sm_statefuns.c 190.3 KB
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/* SCTP kernel implementation
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 * (C) Copyright IBM Corp. 2001, 2004
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 * Copyright (c) 2001-2002 Intel Corp.
 * Copyright (c) 2002      Nokia Corp.
 *
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 * This is part of the SCTP Linux Kernel Implementation.
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 *
 * These are the state functions for the state machine.
 *
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 * This SCTP implementation is free software;
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 * you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
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 * This SCTP implementation is distributed in the hope that it
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 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *                 ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU CC; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <lksctp-developers@lists.sourceforge.net>
 *
 * Or submit a bug report through the following website:
 *    http://www.sf.net/projects/lksctp
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Karl Knutson          <karl@athena.chicago.il.us>
 *    Mathew Kotowsky       <kotowsky@sctp.org>
 *    Sridhar Samudrala     <samudrala@us.ibm.com>
 *    Jon Grimm             <jgrimm@us.ibm.com>
 *    Hui Huang 	    <hui.huang@nokia.com>
 *    Dajiang Zhang 	    <dajiang.zhang@nokia.com>
 *    Daisy Chang	    <daisyc@us.ibm.com>
 *    Ardelle Fan	    <ardelle.fan@intel.com>
 *    Ryan Layer	    <rmlayer@us.ibm.com>
 *    Kevin Gao		    <kevin.gao@intel.com>
 *
 * Any bugs reported given to us we will try to fix... any fixes shared will
 * be incorporated into the next SCTP release.
 */

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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/net.h>
#include <linux/inet.h>
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#include <linux/slab.h>
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#include <net/sock.h>
#include <net/inet_ecn.h>
#include <linux/skbuff.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
#include <net/sctp/structs.h>

static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
				  const struct sctp_association *asoc,
				  struct sctp_chunk *chunk,
				  const void *payload,
				  size_t paylen);
static int sctp_eat_data(const struct sctp_association *asoc,
			 struct sctp_chunk *chunk,
			 sctp_cmd_seq_t *commands);
static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
					     const struct sctp_chunk *chunk);
static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
				       const struct sctp_association *asoc,
				       const struct sctp_chunk *chunk,
				       sctp_cmd_seq_t *commands,
				       struct sctp_chunk *err_chunk);
static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
						 const struct sctp_association *asoc,
						 const sctp_subtype_t type,
						 void *arg,
						 sctp_cmd_seq_t *commands);
static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
					     const struct sctp_association *asoc,
					     const sctp_subtype_t type,
					     void *arg,
					     sctp_cmd_seq_t *commands);
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static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands);
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static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);

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static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
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					   __be16 error, int sk_err,
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					   const struct sctp_association *asoc,
					   struct sctp_transport *transport);

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static sctp_disposition_t sctp_sf_abort_violation(
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				     const struct sctp_endpoint *ep,
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				     const struct sctp_association *asoc,
				     void *arg,
				     sctp_cmd_seq_t *commands,
				     const __u8 *payload,
				     const size_t paylen);

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static sctp_disposition_t sctp_sf_violation_chunklen(
				     const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
				     void *arg,
				     sctp_cmd_seq_t *commands);
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static sctp_disposition_t sctp_sf_violation_paramlen(
				     const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
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				     void *arg, void *ext,
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				     sctp_cmd_seq_t *commands);

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static sctp_disposition_t sctp_sf_violation_ctsn(
				     const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
				     void *arg,
				     sctp_cmd_seq_t *commands);

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static sctp_disposition_t sctp_sf_violation_chunk(
				     const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
				     void *arg,
				     sctp_cmd_seq_t *commands);

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static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep,
				    const struct sctp_association *asoc,
				    const sctp_subtype_t type,
				    struct sctp_chunk *chunk);

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static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands);

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/* Small helper function that checks if the chunk length
 * is of the appropriate length.  The 'required_length' argument
 * is set to be the size of a specific chunk we are testing.
 * Return Values:  1 = Valid length
 * 		   0 = Invalid length
 *
 */
static inline int
sctp_chunk_length_valid(struct sctp_chunk *chunk,
			   __u16 required_length)
{
	__u16 chunk_length = ntohs(chunk->chunk_hdr->length);

	if (unlikely(chunk_length < required_length))
		return 0;

	return 1;
}

/**********************************************************
 * These are the state functions for handling chunk events.
 **********************************************************/

/*
 * Process the final SHUTDOWN COMPLETE.
 *
 * Section: 4 (C) (diagram), 9.2
 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
 * should stop the T2-shutdown timer and remove all knowledge of the
 * association (and thus the association enters the CLOSED state).
 *
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 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
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 * C) Rules for packet carrying SHUTDOWN COMPLETE:
 * ...
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 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
 *   if the Verification Tag field of the packet matches its own tag and
 *   the T bit is not set
 *   OR
 *   it is set to its peer's tag and the T bit is set in the Chunk
 *   Flags.
 *   Otherwise, the receiver MUST silently discard the packet
 *   and take no further action.  An endpoint MUST ignore the
 *   SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
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 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep,
				  const struct sctp_association *asoc,
				  const sctp_subtype_t type,
				  void *arg,
				  sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	struct sctp_ulpevent *ev;

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	if (!sctp_vtag_verify_either(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

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	/* RFC 2960 6.10 Bundling
	 *
	 * An endpoint MUST NOT bundle INIT, INIT ACK or
	 * SHUTDOWN COMPLETE with any other chunks.
	 */
	if (!chunk->singleton)
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		return sctp_sf_violation_chunk(ep, asoc, type, arg, commands);
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	/* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);
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	/* RFC 2960 10.2 SCTP-to-ULP
	 *
	 * H) SHUTDOWN COMPLETE notification
	 *
	 * When SCTP completes the shutdown procedures (section 9.2) this
	 * notification is passed to the upper layer.
	 */
	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
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					     0, 0, 0, NULL, GFP_ATOMIC);
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	if (ev)
		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
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				SCTP_ULPEVENT(ev));
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	/* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
	 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
	 * not the chunk should be discarded. If the endpoint is in
	 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
	 * T2-shutdown timer and remove all knowledge of the
	 * association (and thus the association enters the CLOSED
	 * state).
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));

	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));

	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_CLOSED));

	SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
	SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);

	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());

	return SCTP_DISPOSITION_DELETE_TCB;
}

/*
 * Respond to a normal INIT chunk.
 * We are the side that is being asked for an association.
 *
 * Section: 5.1 Normal Establishment of an Association, B
 * B) "Z" shall respond immediately with an INIT ACK chunk.  The
 *    destination IP address of the INIT ACK MUST be set to the source
 *    IP address of the INIT to which this INIT ACK is responding.  In
 *    the response, besides filling in other parameters, "Z" must set the
 *    Verification Tag field to Tag_A, and also provide its own
 *    Verification Tag (Tag_Z) in the Initiate Tag field.
 *
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 * Verification Tag: Must be 0.
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 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	struct sctp_chunk *repl;
	struct sctp_association *new_asoc;
	struct sctp_chunk *err_chunk;
	struct sctp_packet *packet;
	sctp_unrecognized_param_t *unk_param;
	int len;

	/* 6.10 Bundling
	 * An endpoint MUST NOT bundle INIT, INIT ACK or
	 * SHUTDOWN COMPLETE with any other chunks.
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	 *
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	 * IG Section 2.11.2
	 * Furthermore, we require that the receiver of an INIT chunk MUST
	 * enforce these rules by silently discarding an arriving packet
	 * with an INIT chunk that is bundled with other chunks.
	 */
	if (!chunk->singleton)
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* If the packet is an OOTB packet which is temporarily on the
	 * control endpoint, respond with an ABORT.
	 */
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	if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) {
		SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
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		return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
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	}
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	/* 3.1 A packet containing an INIT chunk MUST have a zero Verification
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	 * Tag.
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	 */
	if (chunk->sctp_hdr->vtag != 0)
		return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);

	/* Make sure that the INIT chunk has a valid length.
	 * Normally, this would cause an ABORT with a Protocol Violation
	 * error, but since we don't have an association, we'll
	 * just discard the packet.
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

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	/* If the INIT is coming toward a closing socket, we'll send back
	 * and ABORT.  Essentially, this catches the race of INIT being
	 * backloged to the socket at the same time as the user isses close().
	 * Since the socket and all its associations are going away, we
	 * can treat this OOTB
	 */
	if (sctp_sstate(ep->base.sk, CLOSING))
		return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);

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	/* Verify the INIT chunk before processing it. */
	err_chunk = NULL;
	if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
			      (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
			      &err_chunk)) {
		/* This chunk contains fatal error. It is to be discarded.
		 * Send an ABORT, with causes if there is any.
		 */
		if (err_chunk) {
			packet = sctp_abort_pkt_new(ep, asoc, arg,
					(__u8 *)(err_chunk->chunk_hdr) +
					sizeof(sctp_chunkhdr_t),
					ntohs(err_chunk->chunk_hdr->length) -
					sizeof(sctp_chunkhdr_t));

			sctp_chunk_free(err_chunk);

			if (packet) {
				sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
						SCTP_PACKET(packet));
				SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
				return SCTP_DISPOSITION_CONSUME;
			} else {
				return SCTP_DISPOSITION_NOMEM;
			}
		} else {
			return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
						    commands);
		}
	}

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	/* Grab the INIT header.  */
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	chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;

	/* Tag the variable length parameters.  */
	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));

	new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
	if (!new_asoc)
		goto nomem;

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	if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
					     sctp_scope(sctp_source(chunk)),
					     GFP_ATOMIC) < 0)
		goto nomem_init;

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	/* The call, sctp_process_init(), can fail on memory allocation.  */
	if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
			       sctp_source(chunk),
			       (sctp_init_chunk_t *)chunk->chunk_hdr,
			       GFP_ATOMIC))
		goto nomem_init;

	/* B) "Z" shall respond immediately with an INIT ACK chunk.  */

	/* If there are errors need to be reported for unknown parameters,
	 * make sure to reserve enough room in the INIT ACK for them.
	 */
	len = 0;
	if (err_chunk)
		len = ntohs(err_chunk->chunk_hdr->length) -
			sizeof(sctp_chunkhdr_t);

	repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
	if (!repl)
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		goto nomem_init;
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	/* If there are errors need to be reported for unknown parameters,
	 * include them in the outgoing INIT ACK as "Unrecognized parameter"
	 * parameter.
	 */
	if (err_chunk) {
		/* Get the "Unrecognized parameter" parameter(s) out of the
		 * ERROR chunk generated by sctp_verify_init(). Since the
		 * error cause code for "unknown parameter" and the
		 * "Unrecognized parameter" type is the same, we can
		 * construct the parameters in INIT ACK by copying the
		 * ERROR causes over.
		 */
		unk_param = (sctp_unrecognized_param_t *)
			    ((__u8 *)(err_chunk->chunk_hdr) +
			    sizeof(sctp_chunkhdr_t));
		/* Replace the cause code with the "Unrecognized parameter"
		 * parameter type.
		 */
		sctp_addto_chunk(repl, len, unk_param);
		sctp_chunk_free(err_chunk);
	}

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	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));

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	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));

	/*
	 * Note:  After sending out INIT ACK with the State Cookie parameter,
	 * "Z" MUST NOT allocate any resources, nor keep any states for the
	 * new association.  Otherwise, "Z" will be vulnerable to resource
	 * attacks.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());

	return SCTP_DISPOSITION_DELETE_TCB;

nomem_init:
	sctp_association_free(new_asoc);
nomem:
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	if (err_chunk)
		sctp_chunk_free(err_chunk);
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	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Respond to a normal INIT ACK chunk.
 * We are the side that is initiating the association.
 *
 * Section: 5.1 Normal Establishment of an Association, C
 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
 *    timer and leave COOKIE-WAIT state. "A" shall then send the State
 *    Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
 *    the T1-cookie timer, and enter the COOKIE-ECHOED state.
 *
 *    Note: The COOKIE ECHO chunk can be bundled with any pending outbound
 *    DATA chunks, but it MUST be the first chunk in the packet and
 *    until the COOKIE ACK is returned the sender MUST NOT send any
 *    other packets to the peer.
 *
 * Verification Tag: 3.3.3
 *   If the value of the Initiate Tag in a received INIT ACK chunk is
 *   found to be 0, the receiver MUST treat it as an error and close the
 *   association by transmitting an ABORT.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep,
				       const struct sctp_association *asoc,
				       const sctp_subtype_t type,
				       void *arg,
				       sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	sctp_init_chunk_t *initchunk;
	struct sctp_chunk *err_chunk;
	struct sctp_packet *packet;

	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* 6.10 Bundling
	 * An endpoint MUST NOT bundle INIT, INIT ACK or
	 * SHUTDOWN COMPLETE with any other chunks.
	 */
	if (!chunk->singleton)
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		return sctp_sf_violation_chunk(ep, asoc, type, arg, commands);
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	/* Make sure that the INIT-ACK chunk has a valid length */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);
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	/* Grab the INIT header.  */
	chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;

	/* Verify the INIT chunk before processing it. */
	err_chunk = NULL;
	if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
			      (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
			      &err_chunk)) {

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		sctp_error_t error = SCTP_ERROR_NO_RESOURCE;

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		/* This chunk contains fatal error. It is to be discarded.
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		 * Send an ABORT, with causes.  If there are no causes,
		 * then there wasn't enough memory.  Just terminate
		 * the association.
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		 */
		if (err_chunk) {
			packet = sctp_abort_pkt_new(ep, asoc, arg,
					(__u8 *)(err_chunk->chunk_hdr) +
					sizeof(sctp_chunkhdr_t),
					ntohs(err_chunk->chunk_hdr->length) -
					sizeof(sctp_chunkhdr_t));

			sctp_chunk_free(err_chunk);

			if (packet) {
				sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
						SCTP_PACKET(packet));
				SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
542
				error = SCTP_ERROR_INV_PARAM;
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Linus Torvalds 已提交
543 544
			}
		}
545 546 547 548 549 550 551 552 553

		/* SCTP-AUTH, Section 6.3:
		 *    It should be noted that if the receiver wants to tear
		 *    down an association in an authenticated way only, the
		 *    handling of malformed packets should not result in
		 *    tearing down the association.
		 *
		 * This means that if we only want to abort associations
		 * in an authenticated way (i.e AUTH+ABORT), then we
L
Lucas De Marchi 已提交
554
		 * can't destroy this association just because the packet
555 556 557 558 559 560
		 * was malformed.
		 */
		if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
			return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

		SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
561 562
		return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED,
						asoc, chunk->transport);
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Linus Torvalds 已提交
563 564 565 566 567 568 569 570 571 572 573 574
	}

	/* Tag the variable length parameters.  Note that we never
	 * convert the parameters in an INIT chunk.
	 */
	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));

	initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;

	sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
			SCTP_PEER_INIT(initchunk));

F
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575 576 577
	/* Reset init error count upon receipt of INIT-ACK.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());

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Linus Torvalds 已提交
578 579 580 581 582 583 584 585 586 587 588
	/* 5.1 C) "A" shall stop the T1-init timer and leave
	 * COOKIE-WAIT state.  "A" shall then ... start the T1-cookie
	 * timer, and enter the COOKIE-ECHOED state.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));

589 590 591 592 593
	/* SCTP-AUTH: genereate the assocition shared keys so that
	 * we can potentially signe the COOKIE-ECHO.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());

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Linus Torvalds 已提交
594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645
	/* 5.1 C) "A" shall then send the State Cookie received in the
	 * INIT ACK chunk in a COOKIE ECHO chunk, ...
	 */
	/* If there is any errors to report, send the ERROR chunk generated
	 * for unknown parameters as well.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
			SCTP_CHUNK(err_chunk));

	return SCTP_DISPOSITION_CONSUME;
}

/*
 * Respond to a normal COOKIE ECHO chunk.
 * We are the side that is being asked for an association.
 *
 * Section: 5.1 Normal Establishment of an Association, D
 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
 *    with a COOKIE ACK chunk after building a TCB and moving to
 *    the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
 *    any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
 *    chunk MUST be the first chunk in the packet.
 *
 *   IMPLEMENTATION NOTE: An implementation may choose to send the
 *   Communication Up notification to the SCTP user upon reception
 *   of a valid COOKIE ECHO chunk.
 *
 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
 * D) Rules for packet carrying a COOKIE ECHO
 *
 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
 *   Initial Tag received in the INIT ACK.
 *
 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep,
				      const struct sctp_association *asoc,
				      const sctp_subtype_t type, void *arg,
				      sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	struct sctp_association *new_asoc;
	sctp_init_chunk_t *peer_init;
	struct sctp_chunk *repl;
646
	struct sctp_ulpevent *ev, *ai_ev = NULL;
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Linus Torvalds 已提交
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	int error = 0;
	struct sctp_chunk *err_chk_p;
649
	struct sock *sk;
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650 651 652 653

	/* If the packet is an OOTB packet which is temporarily on the
	 * control endpoint, respond with an ABORT.
	 */
654 655
	if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) {
		SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
656
		return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
657
	}
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	/* Make sure that the COOKIE_ECHO chunk has a valid length.
	 * In this case, we check that we have enough for at least a
	 * chunk header.  More detailed verification is done
	 * in sctp_unpack_cookie().
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

667 668 669 670 671 672 673 674 675
	/* If the endpoint is not listening or if the number of associations
	 * on the TCP-style socket exceed the max backlog, respond with an
	 * ABORT.
	 */
	sk = ep->base.sk;
	if (!sctp_sstate(sk, LISTENING) ||
	    (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
		return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);

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676 677 678
	/* "Decode" the chunk.  We have no optional parameters so we
	 * are in good shape.
	 */
679
	chunk->subh.cookie_hdr =
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Linus Torvalds 已提交
680
		(struct sctp_signed_cookie *)chunk->skb->data;
681 682 683
	if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
					 sizeof(sctp_chunkhdr_t)))
		goto nomem;
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684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713

	/* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
	 * "Z" will reply with a COOKIE ACK chunk after building a TCB
	 * and moving to the ESTABLISHED state.
	 */
	new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
				      &err_chk_p);

	/* FIXME:
	 * If the re-build failed, what is the proper error path
	 * from here?
	 *
	 * [We should abort the association. --piggy]
	 */
	if (!new_asoc) {
		/* FIXME: Several errors are possible.  A bad cookie should
		 * be silently discarded, but think about logging it too.
		 */
		switch (error) {
		case -SCTP_IERROR_NOMEM:
			goto nomem;

		case -SCTP_IERROR_STALE_COOKIE:
			sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
						   err_chk_p);
			return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

		case -SCTP_IERROR_BAD_SIG:
		default:
			return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
714
		}
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Linus Torvalds 已提交
715 716 717
	}


718 719 720
	/* Delay state machine commands until later.
	 *
	 * Re-build the bind address for the association is done in
L
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721 722 723 724 725 726 727 728
	 * the sctp_unpack_cookie() already.
	 */
	/* This is a brand-new association, so these are not yet side
	 * effects--it is safe to run them here.
	 */
	peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];

	if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
729
			       &chunk->subh.cookie_hdr->c.peer_addr,
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Linus Torvalds 已提交
730 731 732
			       peer_init, GFP_ATOMIC))
		goto nomem_init;

733 734 735 736 737 738 739 740
	/* SCTP-AUTH:  Now that we've populate required fields in
	 * sctp_process_init, set up the assocaition shared keys as
	 * necessary so that we can potentially authenticate the ACK
	 */
	error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
	if (error)
		goto nomem_init;

741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770
	/* SCTP-AUTH:  auth_chunk pointer is only set when the cookie-echo
	 * is supposed to be authenticated and we have to do delayed
	 * authentication.  We've just recreated the association using
	 * the information in the cookie and now it's much easier to
	 * do the authentication.
	 */
	if (chunk->auth_chunk) {
		struct sctp_chunk auth;
		sctp_ierror_t ret;

		/* set-up our fake chunk so that we can process it */
		auth.skb = chunk->auth_chunk;
		auth.asoc = chunk->asoc;
		auth.sctp_hdr = chunk->sctp_hdr;
		auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
					    sizeof(sctp_chunkhdr_t));
		skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
		auth.transport = chunk->transport;

		ret = sctp_sf_authenticate(ep, new_asoc, type, &auth);

		/* We can now safely free the auth_chunk clone */
		kfree_skb(chunk->auth_chunk);

		if (ret != SCTP_IERROR_NO_ERROR) {
			sctp_association_free(new_asoc);
			return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
		}
	}

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Linus Torvalds 已提交
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	repl = sctp_make_cookie_ack(new_asoc, chunk);
	if (!repl)
773
		goto nomem_init;
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774 775 776 777 778 779 780 781 782 783

	/* RFC 2960 5.1 Normal Establishment of an Association
	 *
	 * D) IMPLEMENTATION NOTE: An implementation may choose to
	 * send the Communication Up notification to the SCTP user
	 * upon reception of a valid COOKIE ECHO chunk.
	 */
	ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
					     new_asoc->c.sinit_num_ostreams,
					     new_asoc->c.sinit_max_instreams,
784
					     NULL, GFP_ATOMIC);
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Linus Torvalds 已提交
785 786 787
	if (!ev)
		goto nomem_ev;

788
	/* Sockets API Draft Section 5.3.1.6
789
	 * When a peer sends a Adaptation Layer Indication parameter , SCTP
L
Linus Torvalds 已提交
790
	 * delivers this notification to inform the application that of the
791
	 * peers requested adaptation layer.
L
Linus Torvalds 已提交
792
	 */
793 794
	if (new_asoc->peer.adaptation_ind) {
		ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
L
Linus Torvalds 已提交
795
							    GFP_ATOMIC);
796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823
		if (!ai_ev)
			goto nomem_aiev;
	}

	/* Add all the state machine commands now since we've created
	 * everything.  This way we don't introduce memory corruptions
	 * during side-effect processing and correclty count established
	 * associations.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_ESTABLISHED));
	SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
	SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS);
	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());

	if (new_asoc->autoclose)
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));

	/* This will send the COOKIE ACK */
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));

	/* Queue the ASSOC_CHANGE event */
	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));

	/* Send up the Adaptation Layer Indication event */
	if (ai_ev)
L
Linus Torvalds 已提交
824
		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
825
				SCTP_ULPEVENT(ai_ev));
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Linus Torvalds 已提交
826 827 828

	return SCTP_DISPOSITION_CONSUME;

829 830
nomem_aiev:
	sctp_ulpevent_free(ev);
L
Linus Torvalds 已提交
831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883
nomem_ev:
	sctp_chunk_free(repl);
nomem_init:
	sctp_association_free(new_asoc);
nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Respond to a normal COOKIE ACK chunk.
 * We are the side that is being asked for an association.
 *
 * RFC 2960 5.1 Normal Establishment of an Association
 *
 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
 *    COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
 *    timer. It may also notify its ULP about the successful
 *    establishment of the association with a Communication Up
 *    notification (see Section 10).
 *
 * Verification Tag:
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep,
				      const struct sctp_association *asoc,
				      const sctp_subtype_t type, void *arg,
				      sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	struct sctp_ulpevent *ev;

	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Verify that the chunk length for the COOKIE-ACK is OK.
	 * If we don't do this, any bundled chunks may be junked.
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	/* Reset init error count upon receipt of COOKIE-ACK,
	 * to avoid problems with the managemement of this
	 * counter in stale cookie situations when a transition back
	 * from the COOKIE-ECHOED state to the COOKIE-WAIT
	 * state is performed.
	 */
F
Frank Filz 已提交
884
	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
L
Linus Torvalds 已提交
885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909

	/* RFC 2960 5.1 Normal Establishment of an Association
	 *
	 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
	 * from the COOKIE-ECHOED state to the ESTABLISHED state,
	 * stopping the T1-cookie timer.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_ESTABLISHED));
	SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
	SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS);
	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
	if (asoc->autoclose)
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));

	/* It may also notify its ULP about the successful
	 * establishment of the association with a Communication Up
	 * notification (see Section 10).
	 */
	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
					     0, asoc->c.sinit_num_ostreams,
					     asoc->c.sinit_max_instreams,
910
					     NULL, GFP_ATOMIC);
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Linus Torvalds 已提交
911 912 913 914 915 916 917

	if (!ev)
		goto nomem;

	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));

	/* Sockets API Draft Section 5.3.1.6
918
	 * When a peer sends a Adaptation Layer Indication parameter , SCTP
L
Linus Torvalds 已提交
919
	 * delivers this notification to inform the application that of the
920
	 * peers requested adaptation layer.
L
Linus Torvalds 已提交
921
	 */
922 923
	if (asoc->peer.adaptation_ind) {
		ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
L
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924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949
		if (!ev)
			goto nomem;

		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
				SCTP_ULPEVENT(ev));
	}

	return SCTP_DISPOSITION_CONSUME;
nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/* Generate and sendout a heartbeat packet.  */
static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
					    const struct sctp_association *asoc,
					    const sctp_subtype_t type,
					    void *arg,
					    sctp_cmd_seq_t *commands)
{
	struct sctp_transport *transport = (struct sctp_transport *) arg;
	struct sctp_chunk *reply;
	sctp_sender_hb_info_t hbinfo;
	size_t paylen = 0;

	hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
	hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
950
	hbinfo.daddr = transport->ipaddr;
L
Linus Torvalds 已提交
951
	hbinfo.sent_at = jiffies;
952
	hbinfo.hb_nonce = transport->hb_nonce;
L
Linus Torvalds 已提交
953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978

	/* Send a heartbeat to our peer.  */
	paylen = sizeof(sctp_sender_hb_info_t);
	reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen);
	if (!reply)
		return SCTP_DISPOSITION_NOMEM;

	/* Set rto_pending indicating that an RTT measurement
	 * is started with this heartbeat chunk.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
			SCTP_TRANSPORT(transport));

	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
	return SCTP_DISPOSITION_CONSUME;
}

/* Generate a HEARTBEAT packet on the given transport.  */
sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_transport *transport = (struct sctp_transport *) arg;

979
	if (asoc->overall_error_count >= asoc->max_retrans) {
980 981
		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
				SCTP_ERROR(ETIMEDOUT));
L
Linus Torvalds 已提交
982 983
		/* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
984
				SCTP_PERR(SCTP_ERROR_NO_ERROR));
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Linus Torvalds 已提交
985 986 987 988 989 990 991 992 993 994 995 996
		SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
		SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
		return SCTP_DISPOSITION_DELETE_TCB;
	}

	/* Section 3.3.5.
	 * The Sender-specific Heartbeat Info field should normally include
	 * information about the sender's current time when this HEARTBEAT
	 * chunk is sent and the destination transport address to which this
	 * HEARTBEAT is sent (see Section 8.3).
	 */

997
	if (transport->param_flags & SPP_HB_ENABLE) {
L
Linus Torvalds 已提交
998 999 1000 1001
		if (SCTP_DISPOSITION_NOMEM ==
				sctp_sf_heartbeat(ep, asoc, type, arg,
						  commands))
			return SCTP_DISPOSITION_NOMEM;
1002

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1003 1004 1005
		/* Set transport error counter and association error counter
		 * when sending heartbeat.
		 */
1006
		sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
L
Linus Torvalds 已提交
1007 1008
				SCTP_TRANSPORT(transport));
	}
1009 1010
	sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
			SCTP_TRANSPORT(transport));
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Linus Torvalds 已提交
1011 1012 1013
	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
			SCTP_TRANSPORT(transport));

1014
	return SCTP_DISPOSITION_CONSUME;
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}

/*
 * Process an heartbeat request.
 *
 * Section: 8.3 Path Heartbeat
 * The receiver of the HEARTBEAT should immediately respond with a
 * HEARTBEAT ACK that contains the Heartbeat Information field copied
 * from the received HEARTBEAT chunk.
 *
 * Verification Tag:  8.5 Verification Tag [Normal verification]
 * When receiving an SCTP packet, the endpoint MUST ensure that the
 * value in the Verification Tag field of the received SCTP packet
 * matches its own Tag. If the received Verification Tag value does not
 * match the receiver's own tag value, the receiver shall silently
 * discard the packet and shall not process it any further except for
 * those cases listed in Section 8.5.1 below.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep,
				    const struct sctp_association *asoc,
				    const sctp_subtype_t type,
				    void *arg,
				    sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	struct sctp_chunk *reply;
	size_t paylen = 0;

	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the HEARTBEAT chunk has a valid length. */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	/* 8.3 The receiver of the HEARTBEAT should immediately
	 * respond with a HEARTBEAT ACK that contains the Heartbeat
	 * Information field copied from the received HEARTBEAT chunk.
	 */
	chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
	paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
1065 1066
	if (!pskb_pull(chunk->skb, paylen))
		goto nomem;
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	reply = sctp_make_heartbeat_ack(asoc, chunk,
					chunk->subh.hb_hdr, paylen);
	if (!reply)
		goto nomem;

	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
	return SCTP_DISPOSITION_CONSUME;

nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Process the returning HEARTBEAT ACK.
 *
 * Section: 8.3 Path Heartbeat
 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
 * should clear the error counter of the destination transport
 * address to which the HEARTBEAT was sent, and mark the destination
 * transport address as active if it is not so marked. The endpoint may
 * optionally report to the upper layer when an inactive destination
 * address is marked as active due to the reception of the latest
 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
 * clear the association overall error count as well (as defined
 * in section 8.1).
 *
 * The receiver of the HEARTBEAT ACK should also perform an RTT
 * measurement for that destination transport address using the time
 * value carried in the HEARTBEAT ACK chunk.
 *
 * Verification Tag:  8.5 Verification Tag [Normal verification]
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	union sctp_addr from_addr;
	struct sctp_transport *link;
	sctp_sender_hb_info_t *hbinfo;
	unsigned long max_interval;

	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the HEARTBEAT-ACK chunk has a valid length.  */
1124 1125
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) +
					    sizeof(sctp_sender_hb_info_t)))
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		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
1130 1131 1132 1133 1134 1135
	/* Make sure that the length of the parameter is what we expect */
	if (ntohs(hbinfo->param_hdr.length) !=
				    sizeof(sctp_sender_hb_info_t)) {
		return SCTP_DISPOSITION_DISCARD;
	}

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	from_addr = hbinfo->daddr;
1137
	link = sctp_assoc_lookup_paddr(asoc, &from_addr);
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	/* This should never happen, but lets log it if so.  */
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	if (unlikely(!link)) {
		if (from_addr.sa.sa_family == AF_INET6) {
1142
			if (net_ratelimit())
1143 1144 1145 1146
				pr_warn("%s association %p could not find address %pI6\n",
					__func__,
					asoc,
					&from_addr.v6.sin6_addr);
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		} else {
1148
			if (net_ratelimit())
1149 1150 1151 1152
				pr_warn("%s association %p could not find address %pI4\n",
					__func__,
					asoc,
					&from_addr.v4.sin_addr.s_addr);
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		}
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		return SCTP_DISPOSITION_DISCARD;
	}

1157 1158 1159 1160
	/* Validate the 64-bit random nonce. */
	if (hbinfo->hb_nonce != link->hb_nonce)
		return SCTP_DISPOSITION_DISCARD;

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	max_interval = link->hbinterval + link->rto;
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	/* Check if the timestamp looks valid.  */
	if (time_after(hbinfo->sent_at, jiffies) ||
	    time_after(jiffies, hbinfo->sent_at + max_interval)) {
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		SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp "
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				  "received for transport: %p\n",
1168
				   __func__, link);
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		return SCTP_DISPOSITION_DISCARD;
	}

	/* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
	 * the HEARTBEAT should clear the error counter of the
	 * destination transport address to which the HEARTBEAT was
	 * sent and mark the destination transport address as active if
	 * it is not so marked.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));

	return SCTP_DISPOSITION_CONSUME;
}

/* Helper function to send out an abort for the restart
 * condition.
 */
static int sctp_sf_send_restart_abort(union sctp_addr *ssa,
				      struct sctp_chunk *init,
				      sctp_cmd_seq_t *commands)
{
	int len;
	struct sctp_packet *pkt;
	union sctp_addr_param *addrparm;
	struct sctp_errhdr *errhdr;
	struct sctp_endpoint *ep;
	char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
	struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);

	/* Build the error on the stack.   We are way to malloc crazy
	 * throughout the code today.
	 */
	errhdr = (struct sctp_errhdr *)buffer;
	addrparm = (union sctp_addr_param *)errhdr->variable;

	/* Copy into a parm format. */
	len = af->to_addr_param(ssa, addrparm);
	len += sizeof(sctp_errhdr_t);

	errhdr->cause = SCTP_ERROR_RESTART;
	errhdr->length = htons(len);

	/* Assign to the control socket. */
	ep = sctp_sk((sctp_get_ctl_sock()))->ep;

	/* Association is NULL since this may be a restart attack and we
	 * want to send back the attacker's vtag.
	 */
	pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len);

	if (!pkt)
		goto out;
	sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));

	SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);

	/* Discard the rest of the inbound packet. */
	sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());

out:
	/* Even if there is no memory, treat as a failure so
	 * the packet will get dropped.
	 */
	return 0;
}

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static bool list_has_sctp_addr(const struct list_head *list,
			       union sctp_addr *ipaddr)
{
	struct sctp_transport *addr;

	list_for_each_entry(addr, list, transports) {
		if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
			return true;
	}

	return false;
}
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/* A restart is occurring, check to make sure no new addresses
 * are being added as we may be under a takeover attack.
 */
static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
				       const struct sctp_association *asoc,
				       struct sctp_chunk *init,
				       sctp_cmd_seq_t *commands)
{
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	struct sctp_transport *new_addr;
	int ret = 1;
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	/* Implementor's Guide - Section 5.2.2
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	 * ...
	 * Before responding the endpoint MUST check to see if the
	 * unexpected INIT adds new addresses to the association. If new
	 * addresses are added to the association, the endpoint MUST respond
	 * with an ABORT..
	 */

	/* Search through all current addresses and make sure
	 * we aren't adding any new ones.
	 */
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	list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
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			    transports) {
		if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
					&new_addr->ipaddr)) {
			sctp_sf_send_restart_abort(&new_addr->ipaddr, init,
						   commands);
			ret = 0;
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			break;
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		}
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	}

	/* Return success if all addresses were found. */
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	return ret;
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}

/* Populate the verification/tie tags based on overlapping INIT
 * scenario.
 *
 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
 */
static void sctp_tietags_populate(struct sctp_association *new_asoc,
				  const struct sctp_association *asoc)
{
	switch (asoc->state) {

	/* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */

	case SCTP_STATE_COOKIE_WAIT:
		new_asoc->c.my_vtag     = asoc->c.my_vtag;
		new_asoc->c.my_ttag     = asoc->c.my_vtag;
		new_asoc->c.peer_ttag   = 0;
		break;

	case SCTP_STATE_COOKIE_ECHOED:
		new_asoc->c.my_vtag     = asoc->c.my_vtag;
		new_asoc->c.my_ttag     = asoc->c.my_vtag;
		new_asoc->c.peer_ttag   = asoc->c.peer_vtag;
		break;

	/* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
	 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
	 */
	default:
		new_asoc->c.my_ttag   = asoc->c.my_vtag;
		new_asoc->c.peer_ttag = asoc->c.peer_vtag;
		break;
1315
	}
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1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399

	/* Other parameters for the endpoint SHOULD be copied from the
	 * existing parameters of the association (e.g. number of
	 * outbound streams) into the INIT ACK and cookie.
	 */
	new_asoc->rwnd                  = asoc->rwnd;
	new_asoc->c.sinit_num_ostreams  = asoc->c.sinit_num_ostreams;
	new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
	new_asoc->c.initial_tsn         = asoc->c.initial_tsn;
}

/*
 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
 * handling action.
 *
 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
 *
 * Returns value representing action to be taken.   These action values
 * correspond to Action/Description values in RFC 2960, Table 2.
 */
static char sctp_tietags_compare(struct sctp_association *new_asoc,
				 const struct sctp_association *asoc)
{
	/* In this case, the peer may have restarted.  */
	if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
	    (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
	    (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
	    (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
		return 'A';

	/* Collision case B. */
	if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
	    ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
	     (0 == asoc->c.peer_vtag))) {
		return 'B';
	}

	/* Collision case D. */
	if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
	    (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
		return 'D';

	/* Collision case C. */
	if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
	    (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
	    (0 == new_asoc->c.my_ttag) &&
	    (0 == new_asoc->c.peer_ttag))
		return 'C';

	/* No match to any of the special cases; discard this packet. */
	return 'E';
}

/* Common helper routine for both duplicate and simulataneous INIT
 * chunk handling.
 */
static sctp_disposition_t sctp_sf_do_unexpected_init(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg, sctp_cmd_seq_t *commands)
{
	sctp_disposition_t retval;
	struct sctp_chunk *chunk = arg;
	struct sctp_chunk *repl;
	struct sctp_association *new_asoc;
	struct sctp_chunk *err_chunk;
	struct sctp_packet *packet;
	sctp_unrecognized_param_t *unk_param;
	int len;

	/* 6.10 Bundling
	 * An endpoint MUST NOT bundle INIT, INIT ACK or
	 * SHUTDOWN COMPLETE with any other chunks.
	 *
	 * IG Section 2.11.2
	 * Furthermore, we require that the receiver of an INIT chunk MUST
	 * enforce these rules by silently discarding an arriving packet
	 * with an INIT chunk that is bundled with other chunks.
	 */
	if (!chunk->singleton)
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1400
	 * Tag.
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Linus Torvalds 已提交
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	 */
	if (chunk->sctp_hdr->vtag != 0)
		return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);

	/* Make sure that the INIT chunk has a valid length.
	 * In this case, we generate a protocol violation since we have
	 * an association established.
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);
	/* Grab the INIT header.  */
	chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;

	/* Tag the variable length parameters.  */
	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));

	/* Verify the INIT chunk before processing it. */
	err_chunk = NULL;
	if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
			      (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
			      &err_chunk)) {
		/* This chunk contains fatal error. It is to be discarded.
		 * Send an ABORT, with causes if there is any.
		 */
		if (err_chunk) {
			packet = sctp_abort_pkt_new(ep, asoc, arg,
					(__u8 *)(err_chunk->chunk_hdr) +
					sizeof(sctp_chunkhdr_t),
					ntohs(err_chunk->chunk_hdr->length) -
					sizeof(sctp_chunkhdr_t));

			if (packet) {
				sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
						SCTP_PACKET(packet));
				SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
				retval = SCTP_DISPOSITION_CONSUME;
			} else {
				retval = SCTP_DISPOSITION_NOMEM;
			}
			goto cleanup;
		} else {
			return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
						    commands);
		}
	}

	/*
	 * Other parameters for the endpoint SHOULD be copied from the
	 * existing parameters of the association (e.g. number of
	 * outbound streams) into the INIT ACK and cookie.
	 * FIXME:  We are copying parameters from the endpoint not the
	 * association.
	 */
	new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
	if (!new_asoc)
		goto nomem;

1459 1460 1461 1462
	if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
				sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
		goto nomem;

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	/* In the outbound INIT ACK the endpoint MUST copy its current
	 * Verification Tag and Peers Verification tag into a reserved
	 * place (local tie-tag and per tie-tag) within the state cookie.
	 */
	if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
			       sctp_source(chunk),
			       (sctp_init_chunk_t *)chunk->chunk_hdr,
1470 1471
			       GFP_ATOMIC))
		goto nomem;
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	/* Make sure no new addresses are being added during the
	 * restart.   Do not do this check for COOKIE-WAIT state,
	 * since there are no peer addresses to check against.
	 * Upon return an ABORT will have been sent if needed.
	 */
	if (!sctp_state(asoc, COOKIE_WAIT)) {
		if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
						 commands)) {
			retval = SCTP_DISPOSITION_CONSUME;
1482
			goto nomem_retval;
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1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534
		}
	}

	sctp_tietags_populate(new_asoc, asoc);

	/* B) "Z" shall respond immediately with an INIT ACK chunk.  */

	/* If there are errors need to be reported for unknown parameters,
	 * make sure to reserve enough room in the INIT ACK for them.
	 */
	len = 0;
	if (err_chunk) {
		len = ntohs(err_chunk->chunk_hdr->length) -
			sizeof(sctp_chunkhdr_t);
	}

	repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
	if (!repl)
		goto nomem;

	/* If there are errors need to be reported for unknown parameters,
	 * include them in the outgoing INIT ACK as "Unrecognized parameter"
	 * parameter.
	 */
	if (err_chunk) {
		/* Get the "Unrecognized parameter" parameter(s) out of the
		 * ERROR chunk generated by sctp_verify_init(). Since the
		 * error cause code for "unknown parameter" and the
		 * "Unrecognized parameter" type is the same, we can
		 * construct the parameters in INIT ACK by copying the
		 * ERROR causes over.
		 */
		unk_param = (sctp_unrecognized_param_t *)
			    ((__u8 *)(err_chunk->chunk_hdr) +
			    sizeof(sctp_chunkhdr_t));
		/* Replace the cause code with the "Unrecognized parameter"
		 * parameter type.
		 */
		sctp_addto_chunk(repl, len, unk_param);
	}

	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));

	/*
	 * Note: After sending out INIT ACK with the State Cookie parameter,
	 * "Z" MUST NOT allocate any resources for this new association.
	 * Otherwise, "Z" will be vulnerable to resource attacks.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
	retval = SCTP_DISPOSITION_CONSUME;

1535 1536 1537 1538 1539 1540 1541
	return retval;

nomem:
	retval = SCTP_DISPOSITION_NOMEM;
nomem_retval:
	if (new_asoc)
		sctp_association_free(new_asoc);
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Linus Torvalds 已提交
1542 1543 1544 1545 1546 1547 1548
cleanup:
	if (err_chunk)
		sctp_chunk_free(err_chunk);
	return retval;
}

/*
L
Lucas De Marchi 已提交
1549
 * Handle simultaneous INIT.
L
Linus Torvalds 已提交
1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651
 * This means we started an INIT and then we got an INIT request from
 * our peer.
 *
 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
 * This usually indicates an initialization collision, i.e., each
 * endpoint is attempting, at about the same time, to establish an
 * association with the other endpoint.
 *
 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
 * endpoint MUST respond with an INIT ACK using the same parameters it
 * sent in its original INIT chunk (including its Verification Tag,
 * unchanged). These original parameters are combined with those from the
 * newly received INIT chunk. The endpoint shall also generate a State
 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
 * INIT to calculate the State Cookie.
 *
 * After that, the endpoint MUST NOT change its state, the T1-init
 * timer shall be left running and the corresponding TCB MUST NOT be
 * destroyed. The normal procedures for handling State Cookies when
 * a TCB exists will resolve the duplicate INITs to a single association.
 *
 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
 * its Tie-Tags with the Tag information of itself and its peer (see
 * section 5.2.2 for a description of the Tie-Tags).
 *
 * Verification Tag: Not explicit, but an INIT can not have a valid
 * verification tag, so we skip the check.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep,
				    const struct sctp_association *asoc,
				    const sctp_subtype_t type,
				    void *arg,
				    sctp_cmd_seq_t *commands)
{
	/* Call helper to do the real work for both simulataneous and
	 * duplicate INIT chunk handling.
	 */
	return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
}

/*
 * Handle duplicated INIT messages.  These are usually delayed
 * restransmissions.
 *
 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
 * COOKIE-ECHOED and COOKIE-WAIT
 *
 * Unless otherwise stated, upon reception of an unexpected INIT for
 * this association, the endpoint shall generate an INIT ACK with a
 * State Cookie.  In the outbound INIT ACK the endpoint MUST copy its
 * current Verification Tag and peer's Verification Tag into a reserved
 * place within the state cookie.  We shall refer to these locations as
 * the Peer's-Tie-Tag and the Local-Tie-Tag.  The outbound SCTP packet
 * containing this INIT ACK MUST carry a Verification Tag value equal to
 * the Initiation Tag found in the unexpected INIT.  And the INIT ACK
 * MUST contain a new Initiation Tag (randomly generated see Section
 * 5.3.1).  Other parameters for the endpoint SHOULD be copied from the
 * existing parameters of the association (e.g. number of outbound
 * streams) into the INIT ACK and cookie.
 *
 * After sending out the INIT ACK, the endpoint shall take no further
 * actions, i.e., the existing association, including its current state,
 * and the corresponding TCB MUST NOT be changed.
 *
 * Note: Only when a TCB exists and the association is not in a COOKIE-
 * WAIT state are the Tie-Tags populated.  For a normal association INIT
 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
 * set to 0 (indicating that no previous TCB existed).  The INIT ACK and
 * State Cookie are populated as specified in section 5.2.1.
 *
 * Verification Tag: Not specified, but an INIT has no way of knowing
 * what the verification tag could be, so we ignore it.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	/* Call helper to do the real work for both simulataneous and
	 * duplicate INIT chunk handling.
	 */
	return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
}


1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668
/*
 * Unexpected INIT-ACK handler.
 *
 * Section 5.2.3
 * If an INIT ACK received by an endpoint in any state other than the
 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
 * An unexpected INIT ACK usually indicates the processing of an old or
 * duplicated INIT chunk.
*/
sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep,
					    const struct sctp_association *asoc,
					    const sctp_subtype_t type,
					    void *arg, sctp_cmd_seq_t *commands)
{
	/* Per the above section, we'll discard the chunk if we have an
	 * endpoint.  If this is an OOTB INIT-ACK, treat it as such.
	 */
1669
	if (ep == sctp_sk((sctp_get_ctl_sock()))->ep)
1670 1671 1672 1673
		return sctp_sf_ootb(ep, asoc, type, arg, commands);
	else
		return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
}
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Linus Torvalds 已提交
1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724

/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
 *
 * Section 5.2.4
 *  A)  In this case, the peer may have restarted.
 */
static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					struct sctp_chunk *chunk,
					sctp_cmd_seq_t *commands,
					struct sctp_association *new_asoc)
{
	sctp_init_chunk_t *peer_init;
	struct sctp_ulpevent *ev;
	struct sctp_chunk *repl;
	struct sctp_chunk *err;
	sctp_disposition_t disposition;

	/* new_asoc is a brand-new association, so these are not yet
	 * side effects--it is safe to run them here.
	 */
	peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];

	if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
			       sctp_source(chunk), peer_init,
			       GFP_ATOMIC))
		goto nomem;

	/* Make sure no new addresses are being added during the
	 * restart.  Though this is a pretty complicated attack
	 * since you'd have to get inside the cookie.
	 */
	if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
		return SCTP_DISPOSITION_CONSUME;
	}

	/* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
	 * the peer has restarted (Action A), it MUST NOT setup a new
	 * association but instead resend the SHUTDOWN ACK and send an ERROR
	 * chunk with a "Cookie Received while Shutting Down" error cause to
	 * its peer.
	*/
	if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
		disposition = sctp_sf_do_9_2_reshutack(ep, asoc,
				SCTP_ST_CHUNK(chunk->chunk_hdr->type),
				chunk, commands);
		if (SCTP_DISPOSITION_NOMEM == disposition)
			goto nomem;

		err = sctp_make_op_error(asoc, chunk,
					 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1725
					 NULL, 0, 0);
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Linus Torvalds 已提交
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		if (err)
			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
					SCTP_CHUNK(err));

		return SCTP_DISPOSITION_CONSUME;
	}

	/* For now, fail any unsent/unacked data.  Consider the optional
	 * choice of resending of this data.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());

	repl = sctp_make_cookie_ack(new_asoc, chunk);
	if (!repl)
		goto nomem;

	/* Report association restart to upper layer. */
	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
					     new_asoc->c.sinit_num_ostreams,
					     new_asoc->c.sinit_max_instreams,
1746
					     NULL, GFP_ATOMIC);
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Linus Torvalds 已提交
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	if (!ev)
		goto nomem_ev;

1750 1751 1752
	/* Update the content of current association. */
	sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
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	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
	return SCTP_DISPOSITION_CONSUME;

nomem_ev:
	sctp_chunk_free(repl);
nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
 *
 * Section 5.2.4
 *   B) In this case, both sides may be attempting to start an association
 *      at about the same time but the peer endpoint started its INIT
 *      after responding to the local endpoint's INIT
 */
/* This case represents an initialization collision.  */
static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					struct sctp_chunk *chunk,
					sctp_cmd_seq_t *commands,
					struct sctp_association *new_asoc)
{
	sctp_init_chunk_t *peer_init;
	struct sctp_chunk *repl;

	/* new_asoc is a brand-new association, so these are not yet
	 * side effects--it is safe to run them here.
	 */
	peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
	if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
			       sctp_source(chunk), peer_init,
			       GFP_ATOMIC))
		goto nomem;

	/* Update the content of current association.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_ESTABLISHED));
	SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());

	repl = sctp_make_cookie_ack(new_asoc, chunk);
	if (!repl)
		goto nomem;

	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));

	/* RFC 2960 5.1 Normal Establishment of an Association
	 *
	 * D) IMPLEMENTATION NOTE: An implementation may choose to
	 * send the Communication Up notification to the SCTP user
	 * upon reception of a valid COOKIE ECHO chunk.
1806 1807 1808 1809 1810
	 *
	 * Sadly, this needs to be implemented as a side-effect, because
	 * we are not guaranteed to have set the association id of the real
	 * association and so these notifications need to be delayed until
	 * the association id is allocated.
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Linus Torvalds 已提交
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	 */

1813
	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
L
Linus Torvalds 已提交
1814 1815

	/* Sockets API Draft Section 5.3.1.6
1816
	 * When a peer sends a Adaptation Layer Indication parameter , SCTP
L
Linus Torvalds 已提交
1817
	 * delivers this notification to inform the application that of the
1818
	 * peers requested adaptation layer.
1819 1820 1821
	 *
	 * This also needs to be done as a side effect for the same reason as
	 * above.
L
Linus Torvalds 已提交
1822
	 */
1823 1824
	if (asoc->peer.adaptation_ind)
		sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
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Linus Torvalds 已提交
1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867

	return SCTP_DISPOSITION_CONSUME;

nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
 *
 * Section 5.2.4
 *  C) In this case, the local endpoint's cookie has arrived late.
 *     Before it arrived, the local endpoint sent an INIT and received an
 *     INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
 *     but a new tag of its own.
 */
/* This case represents an initialization collision.  */
static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					struct sctp_chunk *chunk,
					sctp_cmd_seq_t *commands,
					struct sctp_association *new_asoc)
{
	/* The cookie should be silently discarded.
	 * The endpoint SHOULD NOT change states and should leave
	 * any timers running.
	 */
	return SCTP_DISPOSITION_DISCARD;
}

/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
 *
 * Section 5.2.4
 *
 * D) When both local and remote tags match the endpoint should always
 *    enter the ESTABLISHED state, if it has not already done so.
 */
/* This case represents an initialization collision.  */
static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					struct sctp_chunk *chunk,
					sctp_cmd_seq_t *commands,
					struct sctp_association *new_asoc)
{
1868
	struct sctp_ulpevent *ev = NULL, *ai_ev = NULL;
L
Linus Torvalds 已提交
1869 1870 1871 1872
	struct sctp_chunk *repl;

	/* Clarification from Implementor's Guide:
	 * D) When both local and remote tags match the endpoint should
1873 1874 1875
	 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
	 * It should stop any cookie timer that may be running and send
	 * a COOKIE ACK.
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1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894
	 */

	/* Don't accidentally move back into established state. */
	if (asoc->state < SCTP_STATE_ESTABLISHED) {
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
				SCTP_STATE(SCTP_STATE_ESTABLISHED));
		SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
		sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
				SCTP_NULL());

		/* RFC 2960 5.1 Normal Establishment of an Association
		 *
		 * D) IMPLEMENTATION NOTE: An implementation may choose
		 * to send the Communication Up notification to the
		 * SCTP user upon reception of a valid COOKIE
		 * ECHO chunk.
		 */
1895
		ev = sctp_ulpevent_make_assoc_change(asoc, 0,
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Linus Torvalds 已提交
1896
					     SCTP_COMM_UP, 0,
1897 1898
					     asoc->c.sinit_num_ostreams,
					     asoc->c.sinit_max_instreams,
1899
					     NULL, GFP_ATOMIC);
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1900 1901 1902 1903
		if (!ev)
			goto nomem;

		/* Sockets API Draft Section 5.3.1.6
1904
		 * When a peer sends a Adaptation Layer Indication parameter,
L
Linus Torvalds 已提交
1905
		 * SCTP delivers this notification to inform the application
1906
		 * that of the peers requested adaptation layer.
L
Linus Torvalds 已提交
1907
		 */
1908 1909
		if (asoc->peer.adaptation_ind) {
			ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
L
Linus Torvalds 已提交
1910
								 GFP_ATOMIC);
1911
			if (!ai_ev)
L
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				goto nomem;

		}
	}

	repl = sctp_make_cookie_ack(new_asoc, chunk);
	if (!repl)
		goto nomem;

1921 1922
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));

1923 1924 1925 1926 1927 1928 1929
	if (ev)
		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
				SCTP_ULPEVENT(ev));
	if (ai_ev)
		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
					SCTP_ULPEVENT(ai_ev));

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Linus Torvalds 已提交
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	return SCTP_DISPOSITION_CONSUME;

nomem:
1933 1934
	if (ai_ev)
		sctp_ulpevent_free(ai_ev);
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	if (ev)
		sctp_ulpevent_free(ev);
	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Handle a duplicate COOKIE-ECHO.  This usually means a cookie-carrying
 * chunk was retransmitted and then delayed in the network.
 *
 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
 *
 * Verification Tag: None.  Do cookie validation.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	sctp_disposition_t retval;
	struct sctp_chunk *chunk = arg;
	struct sctp_association *new_asoc;
	int error = 0;
	char action;
	struct sctp_chunk *err_chk_p;

	/* Make sure that the chunk has a valid length from the protocol
	 * perspective.  In this case check to make sure we have at least
	 * enough for the chunk header.  Cookie length verification is
	 * done later.
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	/* "Decode" the chunk.  We have no optional parameters so we
	 * are in good shape.
	 */
1981
	chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
1982 1983 1984
	if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
					sizeof(sctp_chunkhdr_t)))
		goto nomem;
L
Linus Torvalds 已提交
1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

	/* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
	 * of a duplicate COOKIE ECHO match the Verification Tags of the
	 * current association, consider the State Cookie valid even if
	 * the lifespan is exceeded.
	 */
	new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
				      &err_chk_p);

	/* FIXME:
	 * If the re-build failed, what is the proper error path
	 * from here?
	 *
	 * [We should abort the association. --piggy]
	 */
	if (!new_asoc) {
		/* FIXME: Several errors are possible.  A bad cookie should
		 * be silently discarded, but think about logging it too.
		 */
		switch (error) {
		case -SCTP_IERROR_NOMEM:
			goto nomem;

		case -SCTP_IERROR_STALE_COOKIE:
			sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
						   err_chk_p);
			return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
		case -SCTP_IERROR_BAD_SIG:
		default:
			return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2015
		}
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Linus Torvalds 已提交
2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046
	}

	/* Compare the tie_tag in cookie with the verification tag of
	 * current association.
	 */
	action = sctp_tietags_compare(new_asoc, asoc);

	switch (action) {
	case 'A': /* Association restart. */
		retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands,
					      new_asoc);
		break;

	case 'B': /* Collision case B. */
		retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands,
					      new_asoc);
		break;

	case 'C': /* Collision case C. */
		retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands,
					      new_asoc);
		break;

	case 'D': /* Collision case D. */
		retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands,
					      new_asoc);
		break;

	default: /* Discard packet for all others. */
		retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands);
		break;
2047
	}
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Linus Torvalds 已提交
2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081

	/* Delete the tempory new association. */
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());

	return retval;

nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Process an ABORT.  (SHUTDOWN-PENDING state)
 *
 * See sctp_sf_do_9_1_abort().
 */
sctp_disposition_t sctp_sf_shutdown_pending_abort(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;

	if (!sctp_vtag_verify_either(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the ABORT chunk has a valid length.
	 * Since this is an ABORT chunk, we have to discard it
	 * because of the following text:
	 * RFC 2960, Section 3.3.7
	 *    If an endpoint receives an ABORT with a format error or for an
	 *    association that doesn't exist, it MUST silently discard it.
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	 * Because the length is "invalid", we can't really discard just
L
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2083 2084 2085 2086 2087 2088
	 * as we do not know its true length.  So, to be safe, discard the
	 * packet.
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

2089 2090 2091 2092 2093 2094 2095 2096 2097 2098
	/* ADD-IP: Special case for ABORT chunks
	 * F4)  One special consideration is that ABORT Chunks arriving
	 * destined to the IP address being deleted MUST be
	 * ignored (see Section 5.3.1 for further details).
	 */
	if (SCTP_ADDR_DEL ==
		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
		return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);

	return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
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}

/*
 * Process an ABORT.  (SHUTDOWN-SENT state)
 *
 * See sctp_sf_do_9_1_abort().
 */
sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;

	if (!sctp_vtag_verify_either(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the ABORT chunk has a valid length.
	 * Since this is an ABORT chunk, we have to discard it
	 * because of the following text:
	 * RFC 2960, Section 3.3.7
	 *    If an endpoint receives an ABORT with a format error or for an
	 *    association that doesn't exist, it MUST silently discard it.
L
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	 * Because the length is "invalid", we can't really discard just
L
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2124 2125 2126 2127 2128 2129
	 * as we do not know its true length.  So, to be safe, discard the
	 * packet.
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

2130 2131 2132 2133 2134 2135 2136 2137 2138
	/* ADD-IP: Special case for ABORT chunks
	 * F4)  One special consideration is that ABORT Chunks arriving
	 * destined to the IP address being deleted MUST be
	 * ignored (see Section 5.3.1 for further details).
	 */
	if (SCTP_ADDR_DEL ==
		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
		return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);

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	/* Stop the T2-shutdown timer. */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));

	/* Stop the T5-shutdown guard timer.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));

2147
	return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
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}

/*
 * Process an ABORT.  (SHUTDOWN-ACK-SENT state)
 *
 * See sctp_sf_do_9_1_abort().
 */
sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	/* The same T2 timer, so we should be able to use
	 * common function with the SHUTDOWN-SENT state.
	 */
	return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands);
}

/*
 * Handle an Error received in COOKIE_ECHOED state.
 *
 * Only handle the error type of stale COOKIE Error, the other errors will
 * be ignored.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	sctp_errhdr_t *err;

	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the ERROR chunk has a valid length.
	 * The parameter walking depends on this as well.
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	/* Process the error here */
	/* FUTURE FIXME:  When PR-SCTP related and other optional
	 * parms are emitted, this will have to change to handle multiple
	 * errors.
	 */
	sctp_walk_errors(err, chunk->chunk_hdr) {
		if (SCTP_ERROR_STALE_COOKIE == err->cause)
2208
			return sctp_sf_do_5_2_6_stale(ep, asoc, type,
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							arg, commands);
	}

	/* It is possible to have malformed error causes, and that
	 * will cause us to end the walk early.  However, since
	 * we are discarding the packet, there should be no adverse
	 * affects.
	 */
	return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
}

/*
 * Handle a Stale COOKIE Error
 *
 * Section: 5.2.6 Handle Stale COOKIE Error
 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
 * one of the following three alternatives.
 * ...
 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
 *    Preservative parameter requesting an extension to the lifetime of
 *    the State Cookie. When calculating the time extension, an
 *    implementation SHOULD use the RTT information measured based on the
 *    previous COOKIE ECHO / ERROR exchange, and should add no more
 *    than 1 second beyond the measured RTT, due to long State Cookie
 *    lifetimes making the endpoint more subject to a replay attack.
 *
 * Verification Tag:  Not explicit, but safe to ignore.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
						 const struct sctp_association *asoc,
						 const sctp_subtype_t type,
						 void *arg,
						 sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	time_t stale;
	sctp_cookie_preserve_param_t bht;
	sctp_errhdr_t *err;
	struct sctp_chunk *reply;
	struct sctp_bind_addr *bp;
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	int attempts = asoc->init_err_counter + 1;
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2259
	if (attempts > asoc->max_init_attempts) {
2260 2261
		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
				SCTP_ERROR(ETIMEDOUT));
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		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2263
				SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
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		return SCTP_DISPOSITION_DELETE_TCB;
	}

	err = (sctp_errhdr_t *)(chunk->skb->data);

	/* When calculating the time extension, an implementation
	 * SHOULD use the RTT information measured based on the
	 * previous COOKIE ECHO / ERROR exchange, and should add no
	 * more than 1 second beyond the measured RTT, due to long
	 * State Cookie lifetimes making the endpoint more subject to
	 * a replay attack.
	 * Measure of Staleness's unit is usec. (1/1000000 sec)
	 * Suggested Cookie Life-span Increment's unit is msec.
	 * (1/1000 sec)
	 * In general, if you use the suggested cookie life, the value
	 * found in the field of measure of staleness should be doubled
	 * to give ample time to retransmit the new cookie and thus
	 * yield a higher probability of success on the reattempt.
	 */
2283
	stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t)));
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	stale = (stale * 2) / 1000;

	bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
	bht.param_hdr.length = htons(sizeof(bht));
	bht.lifespan_increment = htonl(stale);

	/* Build that new INIT chunk.  */
	bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
	reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
	if (!reply)
		goto nomem;

	sctp_addto_chunk(reply, sizeof(bht), &bht);

	/* Clear peer's init_tag cached in assoc as we are sending a new INIT */
	sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());

	/* Stop pending T3-rtx and heartbeat timers */
	sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());

	/* Delete non-primary peer ip addresses since we are transitioning
	 * back to the COOKIE-WAIT state
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());

2310 2311
	/* If we've sent any data bundled with COOKIE-ECHO we will need to
	 * resend
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	 */
2313
	sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
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			SCTP_TRANSPORT(asoc->peer.primary_path));

	/* Cast away the const modifier, as we want to just
	 * rerun it through as a sideffect.
	 */
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	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
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	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));

	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));

	return SCTP_DISPOSITION_CONSUME;

nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Process an ABORT.
 *
 * Section: 9.1
 * After checking the Verification Tag, the receiving endpoint shall
 * remove the association from its record, and shall report the
 * termination to its upper layer.
 *
 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
 * B) Rules for packet carrying ABORT:
 *
 *  - The endpoint shall always fill in the Verification Tag field of the
 *    outbound packet with the destination endpoint's tag value if it
 *    is known.
 *
 *  - If the ABORT is sent in response to an OOTB packet, the endpoint
 *    MUST follow the procedure described in Section 8.4.
 *
 *  - The receiver MUST accept the packet if the Verification Tag
 *    matches either its own tag, OR the tag of its peer. Otherwise, the
 *    receiver MUST silently discard the packet and take no further
 *    action.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;

	if (!sctp_vtag_verify_either(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the ABORT chunk has a valid length.
	 * Since this is an ABORT chunk, we have to discard it
	 * because of the following text:
	 * RFC 2960, Section 3.3.7
	 *    If an endpoint receives an ABORT with a format error or for an
	 *    association that doesn't exist, it MUST silently discard it.
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	 * Because the length is "invalid", we can't really discard just
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	 * as we do not know its true length.  So, to be safe, discard the
	 * packet.
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412
	/* ADD-IP: Special case for ABORT chunks
	 * F4)  One special consideration is that ABORT Chunks arriving
	 * destined to the IP address being deleted MUST be
	 * ignored (see Section 5.3.1 for further details).
	 */
	if (SCTP_ADDR_DEL ==
		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
		return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);

	return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
}

static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	unsigned len;
	__be16 error = SCTP_ERROR_NO_ERROR;

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2413 2414 2415 2416 2417
	/* See if we have an error cause code in the chunk.  */
	len = ntohs(chunk->chunk_hdr->length);
	if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
		error = ((sctp_errhdr_t *)chunk->skb->data)->cause;

2418
	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2419
	/* ASSOC_FAILED will DELETE_TCB. */
2420
	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
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2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439
	SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
	SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);

	return SCTP_DISPOSITION_ABORT;
}

/*
 * Process an ABORT.  (COOKIE-WAIT state)
 *
 * See sctp_sf_do_9_1_abort() above.
 */
sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
				     void *arg,
				     sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	unsigned len;
2440
	__be16 error = SCTP_ERROR_NO_ERROR;
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2441 2442 2443 2444 2445 2446 2447 2448 2449 2450

	if (!sctp_vtag_verify_either(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the ABORT chunk has a valid length.
	 * Since this is an ABORT chunk, we have to discard it
	 * because of the following text:
	 * RFC 2960, Section 3.3.7
	 *    If an endpoint receives an ABORT with a format error or for an
	 *    association that doesn't exist, it MUST silently discard it.
L
Lucas De Marchi 已提交
2451
	 * Because the length is "invalid", we can't really discard just
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	 * as we do not know its true length.  So, to be safe, discard the
	 * packet.
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* See if we have an error cause code in the chunk.  */
	len = ntohs(chunk->chunk_hdr->length);
	if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
		error = ((sctp_errhdr_t *)chunk->skb->data)->cause;

2463 2464
	return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc,
				      chunk->transport);
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}

/*
 * Process an incoming ICMP as an ABORT.  (COOKIE-WAIT state)
 */
sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
2476 2477
	return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR,
				      ENOPROTOOPT, asoc,
F
Frank Filz 已提交
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				      (struct sctp_transport *)arg);
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}

/*
 * Process an ABORT.  (COOKIE-ECHOED state)
 */
sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep,
					       const struct sctp_association *asoc,
					       const sctp_subtype_t type,
					       void *arg,
					       sctp_cmd_seq_t *commands)
{
	/* There is a single T1 timer, so we should be able to use
	 * common function with the COOKIE-WAIT state.
	 */
	return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands);
}

/*
 * Stop T1 timer and abort association with "INIT failed".
 *
 * This is common code called by several sctp_sf_*_abort() functions above.
 */
A
Adrian Bunk 已提交
2501
static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
2502
					   __be16 error, int sk_err,
F
Frank Filz 已提交
2503 2504
					   const struct sctp_association *asoc,
					   struct sctp_transport *transport)
L
Linus Torvalds 已提交
2505
{
F
Frank Filz 已提交
2506
	SCTP_DEBUG_PRINTK("ABORT received (INIT).\n");
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2507 2508 2509 2510 2511
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_CLOSED));
	SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2512
	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
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	/* CMD_INIT_FAILED will DELETE_TCB. */
	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2515
			SCTP_PERR(error));
F
Frank Filz 已提交
2516
	return SCTP_DISPOSITION_ABORT;
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}

/*
 * sctp_sf_do_9_2_shut
 *
 * Section: 9.2
 * Upon the reception of the SHUTDOWN, the peer endpoint shall
 *  - enter the SHUTDOWN-RECEIVED state,
 *
 *  - stop accepting new data from its SCTP user
 *
 *  - verify, by checking the Cumulative TSN Ack field of the chunk,
 *    that all its outstanding DATA chunks have been received by the
 *    SHUTDOWN sender.
 *
 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
 * send a SHUTDOWN in response to a ULP request. And should discard
 * subsequent SHUTDOWN chunks.
 *
 * If there are still outstanding DATA chunks left, the SHUTDOWN
 * receiver shall continue to follow normal data transmission
 * procedures defined in Section 6 until all outstanding DATA chunks
 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
 * new data from its SCTP user.
 *
 * Verification Tag:  8.5 Verification Tag [Normal verification]
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
					   const struct sctp_association *asoc,
					   const sctp_subtype_t type,
					   void *arg,
					   sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	sctp_shutdownhdr_t *sdh;
	sctp_disposition_t disposition;
	struct sctp_ulpevent *ev;
2562
	__u32 ctsn;
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	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the SHUTDOWN chunk has a valid length. */
	if (!sctp_chunk_length_valid(chunk,
				      sizeof(struct sctp_shutdown_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	/* Convert the elaborate header.  */
	sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
	skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
	chunk->subh.shutdown_hdr = sdh;
2577 2578
	ctsn = ntohl(sdh->cum_tsn_ack);

2579 2580 2581 2582 2583 2584
	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
		SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
		SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
		return SCTP_DISPOSITION_DISCARD;
	}

2585 2586 2587 2588 2589 2590
	/* If Cumulative TSN Ack beyond the max tsn currently
	 * send, terminating the association and respond to the
	 * sender with an ABORT.
	 */
	if (!TSN_lt(ctsn, asoc->next_tsn))
		return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
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2592 2593 2594 2595 2596 2597 2598
	/* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
	 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
	 * inform the application that it should cease sending data.
	 */
	ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
	if (!ev) {
		disposition = SCTP_DISPOSITION_NOMEM;
2599
		goto out;
2600 2601 2602
	}
	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));

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	/* Upon the reception of the SHUTDOWN, the peer endpoint shall
	 *  - enter the SHUTDOWN-RECEIVED state,
	 *  - stop accepting new data from its SCTP user
	 *
	 * [This is implicit in the new state.]
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
	disposition = SCTP_DISPOSITION_CONSUME;

	if (sctp_outq_is_empty(&asoc->outqueue)) {
		disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type,
							  arg, commands);
	}

	if (SCTP_DISPOSITION_NOMEM == disposition)
		goto out;

	/*  - verify, by checking the Cumulative TSN Ack field of the
	 *    chunk, that all its outstanding DATA chunks have been
	 *    received by the SHUTDOWN sender.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2626
			SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
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out:
	return disposition;
}

2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647
/*
 * sctp_sf_do_9_2_shut_ctsn
 *
 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
 * it MUST NOT send a SHUTDOWN in response to a ULP request.
 * The Cumulative TSN Ack of the received SHUTDOWN chunk
 * MUST be processed.
 */
sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep,
					   const struct sctp_association *asoc,
					   const sctp_subtype_t type,
					   void *arg,
					   sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	sctp_shutdownhdr_t *sdh;
2648
	__u32 ctsn;
2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659

	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the SHUTDOWN chunk has a valid length. */
	if (!sctp_chunk_length_valid(chunk,
				      sizeof(struct sctp_shutdown_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2660 2661 2662 2663 2664 2665 2666
	ctsn = ntohl(sdh->cum_tsn_ack);

	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
		SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
		SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
		return SCTP_DISPOSITION_DISCARD;
	}
2667 2668 2669 2670 2671

	/* If Cumulative TSN Ack beyond the max tsn currently
	 * send, terminating the association and respond to the
	 * sender with an ABORT.
	 */
2672
	if (!TSN_lt(ctsn, asoc->next_tsn))
2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684
		return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);

	/* verify, by checking the Cumulative TSN Ack field of the
	 * chunk, that all its outstanding DATA chunks have been
	 * received by the SHUTDOWN sender.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
			SCTP_BE32(sdh->cum_tsn_ack));

	return SCTP_DISPOSITION_CONSUME;
}

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/* RFC 2960 9.2
 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
 * transport addresses (either in the IP addresses or in the INIT chunk)
 * that belong to this association, it should discard the INIT chunk and
 * retransmit the SHUTDOWN ACK chunk.
 */
sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep,
				    const struct sctp_association *asoc,
				    const sctp_subtype_t type,
				    void *arg,
				    sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
	struct sctp_chunk *reply;

2701 2702 2703 2704 2705
	/* Make sure that the chunk has a valid length */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

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	/* Since we are not going to really process this INIT, there
	 * is no point in verifying chunk boundries.  Just generate
	 * the SHUTDOWN ACK.
	 */
	reply = sctp_make_shutdown_ack(asoc, chunk);
	if (NULL == reply)
		goto nomem;

	/* Set the transport for the SHUTDOWN ACK chunk and the timeout for
	 * the T2-SHUTDOWN timer.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));

	/* and restart the T2-shutdown timer. */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));

	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));

	return SCTP_DISPOSITION_CONSUME;
nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/*
 * sctp_sf_do_ecn_cwr
 *
 * Section:  Appendix A: Explicit Congestion Notification
 *
 * CWR:
 *
 * RFC 2481 details a specific bit for a sender to send in the header of
 * its next outbound TCP segment to indicate to its peer that it has
 * reduced its congestion window.  This is termed the CWR bit.  For
 * SCTP the same indication is made by including the CWR chunk.
 * This chunk contains one data element, i.e. the TSN number that
 * was sent in the ECNE chunk.  This element represents the lowest
 * TSN number in the datagram that was originally marked with the
 * CE bit.
 *
 * Verification Tag: 8.5 Verification Tag [Normal verification]
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep,
				      const struct sctp_association *asoc,
				      const sctp_subtype_t type,
				      void *arg,
				      sctp_cmd_seq_t *commands)
{
	sctp_cwrhdr_t *cwr;
	struct sctp_chunk *chunk = arg;
2763
	u32 lowest_tsn;
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	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);
2771

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	cwr = (sctp_cwrhdr_t *) chunk->skb->data;
	skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));

2775
	lowest_tsn = ntohl(cwr->lowest_tsn);
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	/* Does this CWR ack the last sent congestion notification? */
2778
	if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
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		/* Stop sending ECNE. */
		sctp_add_cmd_sf(commands,
				SCTP_CMD_ECN_CWR,
2782
				SCTP_U32(lowest_tsn));
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	}
	return SCTP_DISPOSITION_CONSUME;
}

/*
 * sctp_sf_do_ecne
 *
 * Section:  Appendix A: Explicit Congestion Notification
 *
 * ECN-Echo
 *
 * RFC 2481 details a specific bit for a receiver to send back in its
 * TCP acknowledgements to notify the sender of the Congestion
 * Experienced (CE) bit having arrived from the network.  For SCTP this
 * same indication is made by including the ECNE chunk.  This chunk
 * contains one data element, i.e. the lowest TSN associated with the IP
 * datagram marked with the CE bit.....
 *
 * Verification Tag: 8.5 Verification Tag [Normal verification]
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep,
				   const struct sctp_association *asoc,
				   const sctp_subtype_t type,
				   void *arg,
				   sctp_cmd_seq_t *commands)
{
	sctp_ecnehdr_t *ecne;
	struct sctp_chunk *chunk = arg;

	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	ecne = (sctp_ecnehdr_t *) chunk->skb->data;
	skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));

	/* If this is a newer ECNE than the last CWR packet we sent out */
	sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
			SCTP_U32(ntohl(ecne->lowest_tsn)));

	return SCTP_DISPOSITION_CONSUME;
}

/*
 * Section: 6.2  Acknowledgement on Reception of DATA Chunks
 *
 * The SCTP endpoint MUST always acknowledge the reception of each valid
 * DATA chunk.
 *
 * The guidelines on delayed acknowledgement algorithm specified in
 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
 * acknowledgement SHOULD be generated for at least every second packet
 * (not every second DATA chunk) received, and SHOULD be generated within
 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
 * situations it may be beneficial for an SCTP transmitter to be more
 * conservative than the algorithms detailed in this document allow.
 * However, an SCTP transmitter MUST NOT be more aggressive than the
 * following algorithms allow.
 *
 * A SCTP receiver MUST NOT generate more than one SACK for every
 * incoming packet, other than to update the offered window as the
 * receiving application consumes new data.
 *
 * Verification Tag:  8.5 Verification Tag [Normal verification]
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
2873
	sctp_arg_t force = SCTP_NOFORCE();
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	int error;

	if (!sctp_vtag_verify(chunk, asoc)) {
		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
				SCTP_NULL());
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2880
	}
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	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	error = sctp_eat_data(asoc, chunk, commands );
	switch (error) {
	case SCTP_IERROR_NO_ERROR:
		break;
	case SCTP_IERROR_HIGH_TSN:
	case SCTP_IERROR_BAD_STREAM:
2892
		SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
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		goto discard_noforce;
	case SCTP_IERROR_DUP_TSN:
	case SCTP_IERROR_IGNORE_TSN:
2896
		SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
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		goto discard_force;
	case SCTP_IERROR_NO_DATA:
		goto consume;
2900 2901 2902
	case SCTP_IERROR_PROTO_VIOLATION:
		return sctp_sf_abort_violation(ep, asoc, chunk, commands,
			(u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
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	default:
		BUG();
	}

2907 2908 2909
	if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
		force = SCTP_FORCE();

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	if (asoc->autoclose) {
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
	}

	/* If this is the last chunk in a packet, we need to count it
	 * toward sack generation.  Note that we need to SACK every
	 * OTHER packet containing data chunks, EVEN IF WE DISCARD
	 * THEM.  We elect to NOT generate SACK's if the chunk fails
	 * the verification tag test.
	 *
	 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
	 *
	 * The SCTP endpoint MUST always acknowledge the reception of
	 * each valid DATA chunk.
	 *
	 * The guidelines on delayed acknowledgement algorithm
	 * specified in  Section 4.2 of [RFC2581] SHOULD be followed.
	 * Specifically, an acknowledgement SHOULD be generated for at
	 * least every second packet (not every second DATA chunk)
	 * received, and SHOULD be generated within 200 ms of the
	 * arrival of any unacknowledged DATA chunk.  In some
	 * situations it may be beneficial for an SCTP transmitter to
	 * be more conservative than the algorithms detailed in this
	 * document allow. However, an SCTP transmitter MUST NOT be
	 * more aggressive than the following algorithms allow.
	 */
2937
	if (chunk->end_of_packet)
2938
		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
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	return SCTP_DISPOSITION_CONSUME;

discard_force:
	/* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
	 *
	 * When a packet arrives with duplicate DATA chunk(s) and with
	 * no new DATA chunk(s), the endpoint MUST immediately send a
	 * SACK with no delay.  If a packet arrives with duplicate
	 * DATA chunk(s) bundled with new DATA chunks, the endpoint
	 * MAY immediately send a SACK.  Normally receipt of duplicate
	 * DATA chunks will occur when the original SACK chunk was lost
	 * and the peer's RTO has expired.  The duplicate TSN number(s)
	 * SHOULD be reported in the SACK as duplicate.
	 */
	/* In our case, we split the MAY SACK advice up whether or not
	 * the last chunk is a duplicate.'
	 */
	if (chunk->end_of_packet)
		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
	return SCTP_DISPOSITION_DISCARD;

discard_noforce:
2962
	if (chunk->end_of_packet)
2963
		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
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	return SCTP_DISPOSITION_DISCARD;
consume:
	return SCTP_DISPOSITION_CONSUME;
2968

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}

/*
 * sctp_sf_eat_data_fast_4_4
 *
 * Section: 4 (4)
 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
 *    DATA chunks without delay.
 *
 * Verification Tag:  8.5 Verification Tag [Normal verification]
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
				     void *arg,
				     sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	int error;

	if (!sctp_vtag_verify(chunk, asoc)) {
		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
				SCTP_NULL());
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
	}

	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	error = sctp_eat_data(asoc, chunk, commands );
	switch (error) {
	case SCTP_IERROR_NO_ERROR:
	case SCTP_IERROR_HIGH_TSN:
	case SCTP_IERROR_DUP_TSN:
	case SCTP_IERROR_IGNORE_TSN:
	case SCTP_IERROR_BAD_STREAM:
		break;
	case SCTP_IERROR_NO_DATA:
		goto consume;
3016 3017 3018
	case SCTP_IERROR_PROTO_VIOLATION:
		return sctp_sf_abort_violation(ep, asoc, chunk, commands,
			(u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
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	default:
		BUG();
	}

	/* Go a head and force a SACK, since we are shutting down. */

	/* Implementor's Guide.
	 *
	 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
	 * respond to each received packet containing one or more DATA chunk(s)
	 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
	 */
	if (chunk->end_of_packet) {
		/* We must delay the chunk creation since the cumulative
		 * TSN has not been updated yet.
		 */
		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
				SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
	}

consume:
	return SCTP_DISPOSITION_CONSUME;
}

/*
 * Section: 6.2  Processing a Received SACK
 * D) Any time a SACK arrives, the endpoint performs the following:
 *
 *     i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
 *     then drop the SACK.   Since Cumulative TSN Ack is monotonically
 *     increasing, a SACK whose Cumulative TSN Ack is less than the
 *     Cumulative TSN Ack Point indicates an out-of-order SACK.
 *
 *     ii) Set rwnd equal to the newly received a_rwnd minus the number
 *     of bytes still outstanding after processing the Cumulative TSN Ack
 *     and the Gap Ack Blocks.
 *
 *     iii) If the SACK is missing a TSN that was previously
 *     acknowledged via a Gap Ack Block (e.g., the data receiver
 *     reneged on the data), then mark the corresponding DATA chunk
 *     as available for retransmit:  Mark it as missing for fast
 *     retransmit as described in Section 7.2.4 and if no retransmit
 *     timer is running for the destination address to which the DATA
 *     chunk was originally transmitted, then T3-rtx is started for
 *     that destination address.
 *
 * Verification Tag:  8.5 Verification Tag [Normal verification]
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	sctp_sackhdr_t *sackh;
	__u32 ctsn;

	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the SACK chunk has a valid length. */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	/* Pull the SACK chunk from the data buffer */
	sackh = sctp_sm_pull_sack(chunk);
	/* Was this a bogus SACK? */
	if (!sackh)
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
	chunk->subh.sack_hdr = sackh;
	ctsn = ntohl(sackh->cum_tsn_ack);

	/* i) If Cumulative TSN Ack is less than the Cumulative TSN
	 *     Ack Point, then drop the SACK.  Since Cumulative TSN
	 *     Ack is monotonically increasing, a SACK whose
	 *     Cumulative TSN Ack is less than the Cumulative TSN Ack
	 *     Point indicates an out-of-order SACK.
	 */
	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
		SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
		SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
		return SCTP_DISPOSITION_DISCARD;
	}

3115 3116 3117 3118 3119 3120 3121
	/* If Cumulative TSN Ack beyond the max tsn currently
	 * send, terminating the association and respond to the
	 * sender with an ABORT.
	 */
	if (!TSN_lt(ctsn, asoc->next_tsn))
		return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);

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3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133
	/* Return this SACK for further processing.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh));

	/* Note: We do the rest of the work on the PROCESS_SACK
	 * sideeffect.
	 */
	return SCTP_DISPOSITION_CONSUME;
}

/*
 * Generate an ABORT in response to a packet.
 *
3134
 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
L
Linus Torvalds 已提交
3135
 *
3136 3137 3138 3139 3140 3141 3142 3143
 * 8) The receiver should respond to the sender of the OOTB packet with
 *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
 *    MUST fill in the Verification Tag field of the outbound packet
 *    with the value found in the Verification Tag field of the OOTB
 *    packet and set the T-bit in the Chunk Flags to indicate that the
 *    Verification Tag is reflected.  After sending this ABORT, the
 *    receiver of the OOTB packet shall discard the OOTB packet and take
 *    no further action.
L
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3144 3145 3146 3147 3148
 *
 * Verification Tag:
 *
 * The return value is the disposition of the chunk.
*/
3149
static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep,
L
Linus Torvalds 已提交
3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_packet *packet = NULL;
	struct sctp_chunk *chunk = arg;
	struct sctp_chunk *abort;

	packet = sctp_ootb_pkt_new(asoc, chunk);

	if (packet) {
		/* Make an ABORT. The T bit will be set if the asoc
		 * is NULL.
		 */
3165
		abort = sctp_make_abort(asoc, chunk, 0);
L
Linus Torvalds 已提交
3166 3167 3168 3169 3170
		if (!abort) {
			sctp_ootb_pkt_free(packet);
			return SCTP_DISPOSITION_NOMEM;
		}

3171 3172 3173 3174
		/* Reflect vtag if T-Bit is set */
		if (sctp_test_T_bit(abort))
			packet->vtag = ntohl(chunk->sctp_hdr->vtag);

L
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3175 3176 3177 3178 3179 3180 3181 3182 3183 3184
		/* Set the skb to the belonging sock for accounting.  */
		abort->skb->sk = ep->base.sk;

		sctp_packet_append_chunk(packet, abort);

		sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
				SCTP_PACKET(packet));

		SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);

3185
		sctp_sf_pdiscard(ep, asoc, type, arg, commands);
L
Linus Torvalds 已提交
3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215
		return SCTP_DISPOSITION_CONSUME;
	}

	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Received an ERROR chunk from peer.  Generate SCTP_REMOTE_ERROR
 * event as ULP notification for each cause included in the chunk.
 *
 * API 5.3.1.3 - SCTP_REMOTE_ERROR
 *
 * The return value is the disposition of the chunk.
*/
sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;

	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the ERROR chunk has a valid length. */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

3216 3217
	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
			SCTP_CHUNK(chunk));
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Linus Torvalds 已提交
3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254

	return SCTP_DISPOSITION_CONSUME;
}

/*
 * Process an inbound SHUTDOWN ACK.
 *
 * From Section 9.2:
 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
 * peer, and remove all record of the association.
 *
 * The return value is the disposition.
 */
sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	struct sctp_chunk *reply;
	struct sctp_ulpevent *ev;

	if (!sctp_vtag_verify(chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);
	/* 10.2 H) SHUTDOWN COMPLETE notification
	 *
	 * When SCTP completes the shutdown procedures (section 9.2) this
	 * notification is passed to the upper layer.
	 */
	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3255
					     0, 0, 0, NULL, GFP_ATOMIC);
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Linus Torvalds 已提交
3256 3257 3258
	if (!ev)
		goto nomem;

3259 3260 3261 3262 3263 3264 3265 3266
	/* ...send a SHUTDOWN COMPLETE chunk to its peer, */
	reply = sctp_make_shutdown_complete(asoc, chunk);
	if (!reply)
		goto nomem_chunk;

	/* Do all the commands now (after allocation), so that we
	 * have consistent state if memory allocation failes
	 */
L
Linus Torvalds 已提交
3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287
	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));

	/* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
	 * stop the T2-shutdown timer,
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));

	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));

	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_CLOSED));
	SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
	SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));

	/* ...and remove all record of the association. */
	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
	return SCTP_DISPOSITION_DELETE_TCB;

3288 3289
nomem_chunk:
	sctp_ulpevent_free(ev);
L
Linus Torvalds 已提交
3290 3291 3292 3293 3294
nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/*
3295 3296
 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
 *
L
Linus Torvalds 已提交
3297 3298 3299 3300 3301
 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
 *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
 *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
 *    packet must fill in the Verification Tag field of the outbound
 *    packet with the Verification Tag received in the SHUTDOWN ACK and
3302 3303
 *    set the T-bit in the Chunk Flags to indicate that the Verification
 *    Tag is reflected.
L
Linus Torvalds 已提交
3304 3305 3306 3307 3308
 *
 * 8) The receiver should respond to the sender of the OOTB packet with
 *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
 *    MUST fill in the Verification Tag field of the outbound packet
 *    with the value found in the Verification Tag field of the OOTB
3309 3310 3311 3312
 *    packet and set the T-bit in the Chunk Flags to indicate that the
 *    Verification Tag is reflected.  After sending this ABORT, the
 *    receiver of the OOTB packet shall discard the OOTB packet and take
 *    no further action.
L
Linus Torvalds 已提交
3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329
 */
sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep,
				const struct sctp_association *asoc,
				const sctp_subtype_t type,
				void *arg,
				sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	struct sk_buff *skb = chunk->skb;
	sctp_chunkhdr_t *ch;
	__u8 *ch_end;
	int ootb_shut_ack = 0;

	SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);

	ch = (sctp_chunkhdr_t *) chunk->chunk_hdr;
	do {
3330
		/* Report violation if the chunk is less then minimal */
L
Linus Torvalds 已提交
3331
		if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
3332 3333
			return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);
L
Linus Torvalds 已提交
3334

3335 3336 3337
		/* Now that we know we at least have a chunk header,
		 * do things that are type appropriate.
		 */
L
Linus Torvalds 已提交
3338 3339 3340 3341 3342 3343 3344 3345 3346 3347
		if (SCTP_CID_SHUTDOWN_ACK == ch->type)
			ootb_shut_ack = 1;

		/* RFC 2960, Section 3.3.7
		 *   Moreover, under any circumstances, an endpoint that
		 *   receives an ABORT  MUST NOT respond to that ABORT by
		 *   sending an ABORT of its own.
		 */
		if (SCTP_CID_ABORT == ch->type)
			return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3348

3349 3350 3351 3352 3353 3354
		/* Report violation if chunk len overflows */
		ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
		if (ch_end > skb_tail_pointer(skb))
			return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

L
Linus Torvalds 已提交
3355
		ch = (sctp_chunkhdr_t *) ch_end;
3356
	} while (ch_end < skb_tail_pointer(skb));
L
Linus Torvalds 已提交
3357 3358

	if (ootb_shut_ack)
3359
		return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands);
L
Linus Torvalds 已提交
3360
	else
3361
		return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
L
Linus Torvalds 已提交
3362 3363 3364 3365 3366
}

/*
 * Handle an "Out of the blue" SHUTDOWN ACK.
 *
3367 3368
 * Section: 8.4 5, sctpimpguide 2.41.
 *
L
Linus Torvalds 已提交
3369
 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3370 3371 3372 3373 3374 3375
 *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
 *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
 *    packet must fill in the Verification Tag field of the outbound
 *    packet with the Verification Tag received in the SHUTDOWN ACK and
 *    set the T-bit in the Chunk Flags to indicate that the Verification
 *    Tag is reflected.
L
Linus Torvalds 已提交
3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398
 *
 * Inputs
 * (endpoint, asoc, type, arg, commands)
 *
 * Outputs
 * (sctp_disposition_t)
 *
 * The return value is the disposition of the chunk.
 */
static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
					     const struct sctp_association *asoc,
					     const sctp_subtype_t type,
					     void *arg,
					     sctp_cmd_seq_t *commands)
{
	struct sctp_packet *packet = NULL;
	struct sctp_chunk *chunk = arg;
	struct sctp_chunk *shut;

	packet = sctp_ootb_pkt_new(asoc, chunk);

	if (packet) {
		/* Make an SHUTDOWN_COMPLETE.
3399 3400
		 * The T bit will be set if the asoc is NULL.
		 */
L
Linus Torvalds 已提交
3401 3402 3403 3404 3405 3406
		shut = sctp_make_shutdown_complete(asoc, chunk);
		if (!shut) {
			sctp_ootb_pkt_free(packet);
			return SCTP_DISPOSITION_NOMEM;
		}

3407 3408 3409 3410
		/* Reflect vtag if T-Bit is set */
		if (sctp_test_T_bit(shut))
			packet->vtag = ntohl(chunk->sctp_hdr->vtag);

L
Linus Torvalds 已提交
3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426
		/* Set the skb to the belonging sock for accounting.  */
		shut->skb->sk = ep->base.sk;

		sctp_packet_append_chunk(packet, shut);

		sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
				SCTP_PACKET(packet));

		SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);

		/* If the chunk length is invalid, we don't want to process
		 * the reset of the packet.
		 */
		if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
			return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

3427 3428 3429 3430 3431
		/* We need to discard the rest of the packet to prevent
		 * potential bomming attacks from additional bundled chunks.
		 * This is documented in SCTP Threats ID.
		 */
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
L
Linus Torvalds 已提交
3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453
	}

	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
 *
 * Verification Tag:  8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
 *   If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
 *   procedures in section 8.4 SHOULD be followed, in other words it
 *   should be treated as an Out Of The Blue packet.
 *   [This means that we do NOT check the Verification Tag on these
 *   chunks. --piggy ]
 *
 */
sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep,
				      const struct sctp_association *asoc,
				      const sctp_subtype_t type,
				      void *arg,
				      sctp_cmd_seq_t *commands)
{
3454 3455 3456 3457 3458 3459 3460
	struct sctp_chunk *chunk = arg;

	/* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

L
Linus Torvalds 已提交
3461 3462 3463 3464 3465
	/* Although we do have an association in this case, it corresponds
	 * to a restarted association. So the packet is treated as an OOTB
	 * packet and the state function that handles OOTB SHUTDOWN_ACK is
	 * called with a NULL association.
	 */
3466 3467
	SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);

L
Linus Torvalds 已提交
3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478
	return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands);
}

/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.  */
sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type, void *arg,
				     sctp_cmd_seq_t *commands)
{
	struct sctp_chunk	*chunk = arg;
	struct sctp_chunk	*asconf_ack = NULL;
3479
	struct sctp_paramhdr	*err_param = NULL;
L
Linus Torvalds 已提交
3480
	sctp_addiphdr_t		*hdr;
3481
	union sctp_addr_param	*addr_param;
L
Linus Torvalds 已提交
3482
	__u32			serial;
3483
	int			length;
L
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3484 3485 3486 3487 3488 3489 3490

	if (!sctp_vtag_verify(chunk, asoc)) {
		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
				SCTP_NULL());
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
	}

3491 3492 3493 3494 3495 3496 3497 3498 3499
	/* ADD-IP: Section 4.1.1
	 * This chunk MUST be sent in an authenticated way by using
	 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
	 * is received unauthenticated it MUST be silently discarded as
	 * described in [I-D.ietf-tsvwg-sctp-auth].
	 */
	if (!sctp_addip_noauth && !chunk->auth)
		return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);

L
Linus Torvalds 已提交
3500 3501 3502 3503 3504 3505 3506 3507
	/* Make sure that the ASCONF ADDIP chunk has a valid length.  */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	hdr = (sctp_addiphdr_t *)chunk->skb->data;
	serial = ntohl(hdr->serial);

3508 3509 3510
	addr_param = (union sctp_addr_param *)hdr->params;
	length = ntohs(addr_param->p.length);
	if (length < sizeof(sctp_paramhdr_t))
3511
		return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3512 3513 3514 3515
			   (void *)addr_param, commands);

	/* Verify the ASCONF chunk before processing it. */
	if (!sctp_verify_asconf(asoc,
3516 3517 3518
			    (sctp_paramhdr_t *)((void *)addr_param + length),
			    (void *)chunk->chunk_end,
			    &err_param))
3519 3520
		return sctp_sf_violation_paramlen(ep, asoc, type, arg,
						  (void *)err_param, commands);
3521

3522
	/* ADDIP 5.2 E1) Compare the value of the serial number to the value
L
Linus Torvalds 已提交
3523
	 * the endpoint stored in a new association variable
3524
	 * 'Peer-Serial-Number'.
L
Linus Torvalds 已提交
3525 3526
	 */
	if (serial == asoc->peer.addip_serial + 1) {
3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539
		/* If this is the first instance of ASCONF in the packet,
		 * we can clean our old ASCONF-ACKs.
		 */
		if (!chunk->has_asconf)
			sctp_assoc_clean_asconf_ack_cache(asoc);

		/* ADDIP 5.2 E4) When the Sequence Number matches the next one
		 * expected, process the ASCONF as described below and after
		 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
		 * the response packet and cache a copy of it (in the event it
		 * later needs to be retransmitted).
		 *
		 * Essentially, do V1-V5.
L
Linus Torvalds 已提交
3540 3541 3542 3543 3544
		 */
		asconf_ack = sctp_process_asconf((struct sctp_association *)
						 asoc, chunk);
		if (!asconf_ack)
			return SCTP_DISPOSITION_NOMEM;
3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556
	} else if (serial < asoc->peer.addip_serial + 1) {
		/* ADDIP 5.2 E2)
		 * If the value found in the Sequence Number is less than the
		 * ('Peer- Sequence-Number' + 1), simply skip to the next
		 * ASCONF, and include in the outbound response packet
		 * any previously cached ASCONF-ACK response that was
		 * sent and saved that matches the Sequence Number of the
		 * ASCONF.  Note: It is possible that no cached ASCONF-ACK
		 * Chunk exists.  This will occur when an older ASCONF
		 * arrives out of order.  In such a case, the receiver
		 * should skip the ASCONF Chunk and not include ASCONF-ACK
		 * Chunk for that chunk.
L
Linus Torvalds 已提交
3557
		 */
3558 3559
		asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
		if (!asconf_ack)
L
Linus Torvalds 已提交
3560
			return SCTP_DISPOSITION_DISCARD;
3561 3562 3563 3564 3565 3566

		/* Reset the transport so that we select the correct one
		 * this time around.  This is to make sure that we don't
		 * accidentally use a stale transport that's been removed.
		 */
		asconf_ack->transport = NULL;
L
Linus Torvalds 已提交
3567
	} else {
3568
		/* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
L
Linus Torvalds 已提交
3569
		 * it must be either a stale packet or from an attacker.
3570
		 */
L
Linus Torvalds 已提交
3571 3572 3573
		return SCTP_DISPOSITION_DISCARD;
	}

3574 3575 3576 3577 3578 3579 3580
	/* ADDIP 5.2 E6)  The destination address of the SCTP packet
	 * containing the ASCONF-ACK Chunks MUST be the source address of
	 * the SCTP packet that held the ASCONF Chunks.
	 *
	 * To do this properly, we'll set the destination address of the chunk
	 * and at the transmit time, will try look up the transport to use.
	 * Since ASCONFs may be bundled, the correct transport may not be
3581
	 * created until we process the entire packet, thus this workaround.
L
Linus Torvalds 已提交
3582
	 */
3583
	asconf_ack->dest = chunk->source;
L
Linus Torvalds 已提交
3584
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3585

L
Linus Torvalds 已提交
3586 3587 3588 3589 3590 3591 3592 3593 3594 3595
	return SCTP_DISPOSITION_CONSUME;
}

/*
 * ADDIP Section 4.3 General rules for address manipulation
 * When building TLV parameters for the ASCONF Chunk that will add or
 * delete IP addresses the D0 to D13 rules should be applied:
 */
sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
					 const struct sctp_association *asoc,
3596
					 const sctp_subtype_t type, void *arg,
L
Linus Torvalds 已提交
3597 3598 3599 3600 3601
					 sctp_cmd_seq_t *commands)
{
	struct sctp_chunk	*asconf_ack = arg;
	struct sctp_chunk	*last_asconf = asoc->addip_last_asconf;
	struct sctp_chunk	*abort;
3602
	struct sctp_paramhdr	*err_param = NULL;
L
Linus Torvalds 已提交
3603 3604 3605 3606 3607 3608 3609 3610 3611
	sctp_addiphdr_t		*addip_hdr;
	__u32			sent_serial, rcvd_serial;

	if (!sctp_vtag_verify(asconf_ack, asoc)) {
		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
				SCTP_NULL());
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
	}

3612 3613 3614 3615 3616 3617 3618 3619 3620
	/* ADD-IP, Section 4.1.2:
	 * This chunk MUST be sent in an authenticated way by using
	 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
	 * is received unauthenticated it MUST be silently discarded as
	 * described in [I-D.ietf-tsvwg-sctp-auth].
	 */
	if (!sctp_addip_noauth && !asconf_ack->auth)
		return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);

L
Linus Torvalds 已提交
3621 3622 3623 3624 3625 3626 3627 3628
	/* Make sure that the ADDIP chunk has a valid length.  */
	if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
	rcvd_serial = ntohl(addip_hdr->serial);

3629 3630 3631 3632 3633
	/* Verify the ASCONF-ACK chunk before processing it. */
	if (!sctp_verify_asconf(asoc,
	    (sctp_paramhdr_t *)addip_hdr->params,
	    (void *)asconf_ack->chunk_end,
	    &err_param))
3634 3635
		return sctp_sf_violation_paramlen(ep, asoc, type, arg,
			   (void *)err_param, commands);
3636

L
Linus Torvalds 已提交
3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654
	if (last_asconf) {
		addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
		sent_serial = ntohl(addip_hdr->serial);
	} else {
		sent_serial = asoc->addip_serial - 1;
	}

	/* D0) If an endpoint receives an ASCONF-ACK that is greater than or
	 * equal to the next serial number to be used but no ASCONF chunk is
	 * outstanding the endpoint MUST ABORT the association. Note that a
	 * sequence number is greater than if it is no more than 2^^31-1
	 * larger than the current sequence number (using serial arithmetic).
	 */
	if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
	    !(asoc->addip_last_asconf)) {
		abort = sctp_make_abort(asoc, asconf_ack,
					sizeof(sctp_errhdr_t));
		if (abort) {
3655
			sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
L
Linus Torvalds 已提交
3656 3657 3658 3659 3660 3661 3662 3663 3664
			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
					SCTP_CHUNK(abort));
		}
		/* We are going to ABORT, so we might as well stop
		 * processing the rest of the chunks in the packet.
		 */
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3665
		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3666
				SCTP_ERROR(ECONNABORTED));
L
Linus Torvalds 已提交
3667
		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3668
				SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
L
Linus Torvalds 已提交
3669 3670 3671 3672 3673 3674 3675 3676 3677 3678
		SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
		SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
		return SCTP_DISPOSITION_ABORT;
	}

	if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));

		if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3679 3680 3681 3682 3683 3684
					     asconf_ack)) {
			/* Successfully processed ASCONF_ACK.  We can
			 * release the next asconf if we have one.
			 */
			sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF,
					SCTP_NULL());
L
Linus Torvalds 已提交
3685
			return SCTP_DISPOSITION_CONSUME;
3686
		}
L
Linus Torvalds 已提交
3687 3688 3689 3690

		abort = sctp_make_abort(asoc, asconf_ack,
					sizeof(sctp_errhdr_t));
		if (abort) {
3691
			sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
L
Linus Torvalds 已提交
3692 3693 3694 3695 3696 3697 3698
			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
					SCTP_CHUNK(abort));
		}
		/* We are going to ABORT, so we might as well stop
		 * processing the rest of the chunks in the packet.
		 */
		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3699
		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3700
				SCTP_ERROR(ECONNABORTED));
L
Linus Torvalds 已提交
3701
		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3702
				SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
L
Linus Torvalds 已提交
3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732
		SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
		SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
		return SCTP_DISPOSITION_ABORT;
	}

	return SCTP_DISPOSITION_DISCARD;
}

/*
 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
 *
 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
 * its cumulative TSN point to the value carried in the FORWARD TSN
 * chunk, and then MUST further advance its cumulative TSN point locally
 * if possible.
 * After the above processing, the data receiver MUST stop reporting any
 * missing TSNs earlier than or equal to the new cumulative TSN point.
 *
 * Verification Tag:  8.5 Verification Tag [Normal verification]
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep,
				       const struct sctp_association *asoc,
				       const sctp_subtype_t type,
				       void *arg,
				       sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3733
	struct sctp_fwdtsn_skip *skip;
L
Linus Torvalds 已提交
3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754
	__u16 len;
	__u32 tsn;

	if (!sctp_vtag_verify(chunk, asoc)) {
		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
				SCTP_NULL());
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
	}

	/* Make sure that the FORWARD_TSN chunk has valid length.  */
	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
	chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
	len = ntohs(chunk->chunk_hdr->length);
	len -= sizeof(struct sctp_chunkhdr);
	skb_pull(chunk->skb, len);

	tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3755
	SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
L
Linus Torvalds 已提交
3756 3757 3758 3759 3760 3761 3762

	/* The TSN is too high--silently discard the chunk and count on it
	 * getting retransmitted later.
	 */
	if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
		goto discard_noforce;

3763 3764 3765 3766 3767 3768
	/* Silently discard the chunk if stream-id is not valid */
	sctp_walk_fwdtsn(skip, chunk) {
		if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
			goto discard_noforce;
	}

L
Linus Torvalds 已提交
3769 3770
	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
	if (len > sizeof(struct sctp_fwdtsn_hdr))
3771
		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
L
Linus Torvalds 已提交
3772
				SCTP_CHUNK(chunk));
3773

L
Linus Torvalds 已提交
3774 3775 3776 3777 3778
	/* Count this as receiving DATA. */
	if (asoc->autoclose) {
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
	}
3779

L
Linus Torvalds 已提交
3780
	/* FIXME: For now send a SACK, but DATA processing may
3781
	 * send another.
L
Linus Torvalds 已提交
3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());

	return SCTP_DISPOSITION_CONSUME;

discard_noforce:
	return SCTP_DISPOSITION_DISCARD;
}

sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;
	struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3800
	struct sctp_fwdtsn_skip *skip;
L
Linus Torvalds 已提交
3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821
	__u16 len;
	__u32 tsn;

	if (!sctp_vtag_verify(chunk, asoc)) {
		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
				SCTP_NULL());
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
	}

	/* Make sure that the FORWARD_TSN chunk has a valid length.  */
	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
	chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
	len = ntohs(chunk->chunk_hdr->length);
	len -= sizeof(struct sctp_chunkhdr);
	skb_pull(chunk->skb, len);

	tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3822
	SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
L
Linus Torvalds 已提交
3823 3824 3825 3826 3827 3828 3829

	/* The TSN is too high--silently discard the chunk and count on it
	 * getting retransmitted later.
	 */
	if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
		goto gen_shutdown;

3830 3831 3832 3833 3834 3835
	/* Silently discard the chunk if stream-id is not valid */
	sctp_walk_fwdtsn(skip, chunk) {
		if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
			goto gen_shutdown;
	}

L
Linus Torvalds 已提交
3836 3837
	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
	if (len > sizeof(struct sctp_fwdtsn_hdr))
3838
		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
L
Linus Torvalds 已提交
3839
				SCTP_CHUNK(chunk));
3840

L
Linus Torvalds 已提交
3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853
	/* Go a head and force a SACK, since we are shutting down. */
gen_shutdown:
	/* Implementor's Guide.
	 *
	 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
	 * respond to each received packet containing one or more DATA chunk(s)
	 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));

3854
	return SCTP_DISPOSITION_CONSUME;
L
Linus Torvalds 已提交
3855 3856
}

3857
/*
L
Lucas De Marchi 已提交
3858
 * SCTP-AUTH Section 6.3 Receiving authenticated chukns
3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962
 *
 *    The receiver MUST use the HMAC algorithm indicated in the HMAC
 *    Identifier field.  If this algorithm was not specified by the
 *    receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
 *    during association setup, the AUTH chunk and all chunks after it MUST
 *    be discarded and an ERROR chunk SHOULD be sent with the error cause
 *    defined in Section 4.1.
 *
 *    If an endpoint with no shared key receives a Shared Key Identifier
 *    other than 0, it MUST silently discard all authenticated chunks.  If
 *    the endpoint has at least one endpoint pair shared key for the peer,
 *    it MUST use the key specified by the Shared Key Identifier if a
 *    key has been configured for that Shared Key Identifier.  If no
 *    endpoint pair shared key has been configured for that Shared Key
 *    Identifier, all authenticated chunks MUST be silently discarded.
 *
 * Verification Tag:  8.5 Verification Tag [Normal verification]
 *
 * The return value is the disposition of the chunk.
 */
static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep,
				    const struct sctp_association *asoc,
				    const sctp_subtype_t type,
				    struct sctp_chunk *chunk)
{
	struct sctp_authhdr *auth_hdr;
	struct sctp_hmac *hmac;
	unsigned int sig_len;
	__u16 key_id;
	__u8 *save_digest;
	__u8 *digest;

	/* Pull in the auth header, so we can do some more verification */
	auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
	chunk->subh.auth_hdr = auth_hdr;
	skb_pull(chunk->skb, sizeof(struct sctp_authhdr));

	/* Make sure that we suport the HMAC algorithm from the auth
	 * chunk.
	 */
	if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
		return SCTP_IERROR_AUTH_BAD_HMAC;

	/* Make sure that the provided shared key identifier has been
	 * configured
	 */
	key_id = ntohs(auth_hdr->shkey_id);
	if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id))
		return SCTP_IERROR_AUTH_BAD_KEYID;


	/* Make sure that the length of the signature matches what
	 * we expect.
	 */
	sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t);
	hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
	if (sig_len != hmac->hmac_len)
		return SCTP_IERROR_PROTO_VIOLATION;

	/* Now that we've done validation checks, we can compute and
	 * verify the hmac.  The steps involved are:
	 *  1. Save the digest from the chunk.
	 *  2. Zero out the digest in the chunk.
	 *  3. Compute the new digest
	 *  4. Compare saved and new digests.
	 */
	digest = auth_hdr->hmac;
	skb_pull(chunk->skb, sig_len);

	save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
	if (!save_digest)
		goto nomem;

	memset(digest, 0, sig_len);

	sctp_auth_calculate_hmac(asoc, chunk->skb,
				(struct sctp_auth_chunk *)chunk->chunk_hdr,
				GFP_ATOMIC);

	/* Discard the packet if the digests do not match */
	if (memcmp(save_digest, digest, sig_len)) {
		kfree(save_digest);
		return SCTP_IERROR_BAD_SIG;
	}

	kfree(save_digest);
	chunk->auth = 1;

	return SCTP_IERROR_NO_ERROR;
nomem:
	return SCTP_IERROR_NOMEM;
}

sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep,
				    const struct sctp_association *asoc,
				    const sctp_subtype_t type,
				    void *arg,
				    sctp_cmd_seq_t *commands)
{
	struct sctp_authhdr *auth_hdr;
	struct sctp_chunk *chunk = arg;
	struct sctp_chunk *err_chunk;
	sctp_ierror_t error;

3963 3964 3965 3966
	/* Make sure that the peer has AUTH capable */
	if (!asoc->peer.auth_capable)
		return sctp_sf_unk_chunk(ep, asoc, type, arg, commands);

3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987
	if (!sctp_vtag_verify(chunk, asoc)) {
		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
				SCTP_NULL());
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
	}

	/* Make sure that the AUTH chunk has valid length.  */
	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
	error = sctp_sf_authenticate(ep, asoc, type, chunk);
	switch (error) {
		case SCTP_IERROR_AUTH_BAD_HMAC:
			/* Generate the ERROR chunk and discard the rest
			 * of the packet
			 */
			err_chunk = sctp_make_op_error(asoc, chunk,
							SCTP_ERROR_UNSUP_HMAC,
							&auth_hdr->hmac_id,
3988
							sizeof(__u16), 0);
3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007
			if (err_chunk) {
				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
						SCTP_CHUNK(err_chunk));
			}
			/* Fall Through */
		case SCTP_IERROR_AUTH_BAD_KEYID:
		case SCTP_IERROR_BAD_SIG:
			return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
			break;
		case SCTP_IERROR_PROTO_VIOLATION:
			return sctp_sf_violation_chunklen(ep, asoc, type, arg,
							  commands);
			break;
		case SCTP_IERROR_NOMEM:
			return SCTP_DISPOSITION_NOMEM;
		default:
			break;
	}

4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020
	if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
		struct sctp_ulpevent *ev;

		ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
				    SCTP_AUTH_NEWKEY, GFP_ATOMIC);

		if (!ev)
			return -ENOMEM;

		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
				SCTP_ULPEVENT(ev));
	}

4021 4022 4023
	return SCTP_DISPOSITION_CONSUME;
}

L
Linus Torvalds 已提交
4024 4025 4026 4027 4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048 4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076 4077 4078 4079
/*
 * Process an unknown chunk.
 *
 * Section: 3.2. Also, 2.1 in the implementor's guide.
 *
 * Chunk Types are encoded such that the highest-order two bits specify
 * the action that must be taken if the processing endpoint does not
 * recognize the Chunk Type.
 *
 * 00 - Stop processing this SCTP packet and discard it, do not process
 *      any further chunks within it.
 *
 * 01 - Stop processing this SCTP packet and discard it, do not process
 *      any further chunks within it, and report the unrecognized
 *      chunk in an 'Unrecognized Chunk Type'.
 *
 * 10 - Skip this chunk and continue processing.
 *
 * 11 - Skip this chunk and continue processing, but report in an ERROR
 *      Chunk using the 'Unrecognized Chunk Type' cause of error.
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
				     void *arg,
				     sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *unk_chunk = arg;
	struct sctp_chunk *err_chunk;
	sctp_chunkhdr_t *hdr;

	SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk);

	if (!sctp_vtag_verify(unk_chunk, asoc))
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

	/* Make sure that the chunk has a valid length.
	 * Since we don't know the chunk type, we use a general
	 * chunkhdr structure to make a comparison.
	 */
	if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

	switch (type.chunk & SCTP_CID_ACTION_MASK) {
	case SCTP_CID_ACTION_DISCARD:
		/* Discard the packet.  */
		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
		break;
	case SCTP_CID_ACTION_DISCARD_ERR:
		/* Generate an ERROR chunk as response. */
		hdr = unk_chunk->chunk_hdr;
		err_chunk = sctp_make_op_error(asoc, unk_chunk,
					       SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4080 4081
					       WORD_ROUND(ntohs(hdr->length)),
					       0);
L
Linus Torvalds 已提交
4082 4083 4084 4085
		if (err_chunk) {
			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
					SCTP_CHUNK(err_chunk));
		}
4086 4087 4088

		/* Discard the packet.  */
		sctp_sf_pdiscard(ep, asoc, type, arg, commands);
L
Linus Torvalds 已提交
4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099
		return SCTP_DISPOSITION_CONSUME;
		break;
	case SCTP_CID_ACTION_SKIP:
		/* Skip the chunk.  */
		return SCTP_DISPOSITION_DISCARD;
		break;
	case SCTP_CID_ACTION_SKIP_ERR:
		/* Generate an ERROR chunk as response. */
		hdr = unk_chunk->chunk_hdr;
		err_chunk = sctp_make_op_error(asoc, unk_chunk,
					       SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4100 4101
					       WORD_ROUND(ntohs(hdr->length)),
					       0);
L
Linus Torvalds 已提交
4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135
		if (err_chunk) {
			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
					SCTP_CHUNK(err_chunk));
		}
		/* Skip the chunk.  */
		return SCTP_DISPOSITION_CONSUME;
		break;
	default:
		break;
	}

	return SCTP_DISPOSITION_DISCARD;
}

/*
 * Discard the chunk.
 *
 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
 * [Too numerous to mention...]
 * Verification Tag: No verification needed.
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep,
					 const struct sctp_association *asoc,
					 const sctp_subtype_t type,
					 void *arg,
					 sctp_cmd_seq_t *commands)
{
4136 4137 4138 4139 4140 4141 4142 4143 4144 4145
	struct sctp_chunk *chunk = arg;

	/* Make sure that the chunk has a valid length.
	 * Since we don't know the chunk type, we use a general
	 * chunkhdr structure to make a comparison.
	 */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

L
Linus Torvalds 已提交
4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173
	SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk);
	return SCTP_DISPOSITION_DISCARD;
}

/*
 * Discard the whole packet.
 *
 * Section: 8.4 2)
 *
 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
 *    silently discard the OOTB packet and take no further action.
 *
 * Verification Tag: No verification necessary
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep,
				    const struct sctp_association *asoc,
				    const sctp_subtype_t type,
				    void *arg,
				    sctp_cmd_seq_t *commands)
{
4174
	SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS);
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Linus Torvalds 已提交
4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195 4196 4197 4198 4199 4200
	sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());

	return SCTP_DISPOSITION_CONSUME;
}


/*
 * The other end is violating protocol.
 *
 * Section: Not specified
 * Verification Tag: Not specified
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (asoc, reply_msg, msg_up, timers, counters)
 *
 * We simply tag the chunk as a violation.  The state machine will log
 * the violation and continue.
 */
sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
				     void *arg,
				     sctp_cmd_seq_t *commands)
{
4201 4202 4203 4204 4205 4206 4207
	struct sctp_chunk *chunk = arg;

	/* Make sure that the chunk has a valid length. */
	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
						  commands);

L
Linus Torvalds 已提交
4208 4209 4210 4211
	return SCTP_DISPOSITION_VIOLATION;
}

/*
4212
 * Common function to handle a protocol violation.
L
Linus Torvalds 已提交
4213
 */
4214
static sctp_disposition_t sctp_sf_abort_violation(
4215
				     const struct sctp_endpoint *ep,
L
Linus Torvalds 已提交
4216 4217
				     const struct sctp_association *asoc,
				     void *arg,
4218 4219 4220
				     sctp_cmd_seq_t *commands,
				     const __u8 *payload,
				     const size_t paylen)
L
Linus Torvalds 已提交
4221
{
4222
	struct sctp_packet *packet = NULL;
L
Linus Torvalds 已提交
4223 4224 4225
	struct sctp_chunk *chunk =  arg;
	struct sctp_chunk *abort = NULL;

4226 4227 4228 4229 4230 4231 4232 4233
	/* SCTP-AUTH, Section 6.3:
	 *    It should be noted that if the receiver wants to tear
	 *    down an association in an authenticated way only, the
	 *    handling of malformed packets should not result in
	 *    tearing down the association.
	 *
	 * This means that if we only want to abort associations
	 * in an authenticated way (i.e AUTH+ABORT), then we
L
Lucas De Marchi 已提交
4234
	 * can't destroy this association just because the packet
4235 4236 4237 4238 4239
	 * was malformed.
	 */
	if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
		goto discard;

4240 4241 4242 4243 4244
	/* Make the abort chunk. */
	abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
	if (!abort)
		goto nomem;

4245
	if (asoc) {
4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263
		/* Treat INIT-ACK as a special case during COOKIE-WAIT. */
		if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
		    !asoc->peer.i.init_tag) {
			sctp_initack_chunk_t *initack;

			initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
			if (!sctp_chunk_length_valid(chunk,
						     sizeof(sctp_initack_chunk_t)))
				abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
			else {
				unsigned int inittag;

				inittag = ntohl(initack->init_hdr.init_tag);
				sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
						SCTP_U32(inittag));
			}
		}

4264 4265
		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
		SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
L
Linus Torvalds 已提交
4266

4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280
		if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
					SCTP_ERROR(ECONNREFUSED));
			sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
					SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
		} else {
			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
					SCTP_ERROR(ECONNABORTED));
			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
					SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
			SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
		}
L
Linus Torvalds 已提交
4281
	} else {
4282 4283 4284 4285 4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297
		packet = sctp_ootb_pkt_new(asoc, chunk);

		if (!packet)
			goto nomem_pkt;

		if (sctp_test_T_bit(abort))
			packet->vtag = ntohl(chunk->sctp_hdr->vtag);

		abort->skb->sk = ep->base.sk;

		sctp_packet_append_chunk(packet, abort);

		sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
			SCTP_PACKET(packet));

		SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
L
Linus Torvalds 已提交
4298 4299 4300
	}

	SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4301

4302 4303
discard:
	sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
L
Linus Torvalds 已提交
4304 4305
	return SCTP_DISPOSITION_ABORT;

4306 4307
nomem_pkt:
	sctp_chunk_free(abort);
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Linus Torvalds 已提交
4308 4309 4310 4311
nomem:
	return SCTP_DISPOSITION_NOMEM;
}

4312 4313
/*
 * Handle a protocol violation when the chunk length is invalid.
4314
 * "Invalid" length is identified as smaller than the minimal length a
4315
 * given chunk can be.  For example, a SACK chunk has invalid length
4316
 * if its length is set to be smaller than the size of sctp_sack_chunk_t.
4317 4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337
 *
 * We inform the other end by sending an ABORT with a Protocol Violation
 * error code.
 *
 * Section: Not specified
 * Verification Tag:  Nothing to do
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * Outputs
 * (reply_msg, msg_up, counters)
 *
 * Generate an  ABORT chunk and terminate the association.
 */
static sctp_disposition_t sctp_sf_violation_chunklen(
				     const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
				     void *arg,
				     sctp_cmd_seq_t *commands)
{
4338
	static const char err_str[]="The following chunk had invalid length:";
4339

4340
	return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4341 4342 4343
					sizeof(err_str));
}

4344 4345
/*
 * Handle a protocol violation when the parameter length is invalid.
4346
 * "Invalid" length is identified as smaller than the minimal length a
4347 4348 4349 4350 4351 4352
 * given parameter can be.
 */
static sctp_disposition_t sctp_sf_violation_paramlen(
				     const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
4353 4354 4355 4356 4357 4358
				     void *arg, void *ext,
				     sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk =  arg;
	struct sctp_paramhdr *param = ext;
	struct sctp_chunk *abort = NULL;
4359

4360 4361 4362 4363 4364 4365 4366 4367 4368 4369 4370 4371 4372 4373 4374 4375
	if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
		goto discard;

	/* Make the abort chunk. */
	abort = sctp_make_violation_paramlen(asoc, chunk, param);
	if (!abort)
		goto nomem;

	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
	SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);

	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
			SCTP_ERROR(ECONNABORTED));
	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
			SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
	SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4376
	SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4377 4378 4379 4380 4381 4382

discard:
	sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
	return SCTP_DISPOSITION_ABORT;
nomem:
	return SCTP_DISPOSITION_NOMEM;
4383 4384
}

4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397
/* Handle a protocol violation when the peer trying to advance the
 * cumulative tsn ack to a point beyond the max tsn currently sent.
 *
 * We inform the other end by sending an ABORT with a Protocol Violation
 * error code.
 */
static sctp_disposition_t sctp_sf_violation_ctsn(
				     const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
				     void *arg,
				     sctp_cmd_seq_t *commands)
{
4398
	static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:";
4399

4400
	return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4401 4402 4403
					sizeof(err_str));
}

4404
/* Handle protocol violation of an invalid chunk bundling.  For example,
L
Lucas De Marchi 已提交
4405
 * when we have an association and we receive bundled INIT-ACK, or
4406
 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
L
Lucas De Marchi 已提交
4407
 * statement from the specs.  Additionally, there might be an attacker
4408 4409 4410 4411 4412 4413 4414 4415 4416
 * on the path and we may not want to continue this communication.
 */
static sctp_disposition_t sctp_sf_violation_chunk(
				     const struct sctp_endpoint *ep,
				     const struct sctp_association *asoc,
				     const sctp_subtype_t type,
				     void *arg,
				     sctp_cmd_seq_t *commands)
{
4417
	static const char err_str[]="The following chunk violates protocol:";
4418 4419 4420 4421 4422 4423 4424

	if (!asoc)
		return sctp_sf_violation(ep, asoc, type, arg, commands);

	return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
					sizeof(err_str));
}
L
Linus Torvalds 已提交
4425 4426 4427 4428 4429 4430 4431 4432 4433 4434 4435 4436 4437 4438 4439 4440 4441 4442 4443 4444 4445 4446 4447 4448 4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464 4465 4466 4467 4468 4469 4470 4471 4472 4473 4474 4475 4476 4477 4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490 4491
/***************************************************************************
 * These are the state functions for handling primitive (Section 10) events.
 ***************************************************************************/
/*
 * sctp_sf_do_prm_asoc
 *
 * Section: 10.1 ULP-to-SCTP
 * B) Associate
 *
 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
 * outbound stream count)
 * -> association id [,destination transport addr list] [,outbound stream
 * count]
 *
 * This primitive allows the upper layer to initiate an association to a
 * specific peer endpoint.
 *
 * The peer endpoint shall be specified by one of the transport addresses
 * which defines the endpoint (see Section 1.4).  If the local SCTP
 * instance has not been initialized, the ASSOCIATE is considered an
 * error.
 * [This is not relevant for the kernel implementation since we do all
 * initialization at boot time.  It we hadn't initialized we wouldn't
 * get anywhere near this code.]
 *
 * An association id, which is a local handle to the SCTP association,
 * will be returned on successful establishment of the association. If
 * SCTP is not able to open an SCTP association with the peer endpoint,
 * an error is returned.
 * [In the kernel implementation, the struct sctp_association needs to
 * be created BEFORE causing this primitive to run.]
 *
 * Other association parameters may be returned, including the
 * complete destination transport addresses of the peer as well as the
 * outbound stream count of the local endpoint. One of the transport
 * address from the returned destination addresses will be selected by
 * the local endpoint as default primary path for sending SCTP packets
 * to this peer.  The returned "destination transport addr list" can
 * be used by the ULP to change the default primary path or to force
 * sending a packet to a specific transport address.  [All of this
 * stuff happens when the INIT ACK arrives.  This is a NON-BLOCKING
 * function.]
 *
 * Mandatory attributes:
 *
 * o local SCTP instance name - obtained from the INITIALIZE operation.
 *   [This is the argument asoc.]
 * o destination transport addr - specified as one of the transport
 * addresses of the peer endpoint with which the association is to be
 * established.
 *  [This is asoc->peer.active_path.]
 * o outbound stream count - the number of outbound streams the ULP
 * would like to open towards this peer endpoint.
 * [BUG: This is not currently implemented.]
 * Optional attributes:
 *
 * None.
 *
 * The return value is a disposition.
 */
sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep,
				       const struct sctp_association *asoc,
				       const sctp_subtype_t type,
				       void *arg,
				       sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *repl;
4492
	struct sctp_association* my_asoc;
L
Linus Torvalds 已提交
4493 4494 4495 4496 4497 4498 4499 4500 4501 4502 4503 4504 4505 4506 4507 4508 4509 4510 4511 4512 4513 4514 4515

	/* The comment below says that we enter COOKIE-WAIT AFTER
	 * sending the INIT, but that doesn't actually work in our
	 * implementation...
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));

	/* RFC 2960 5.1 Normal Establishment of an Association
	 *
	 * A) "A" first sends an INIT chunk to "Z".  In the INIT, "A"
	 * must provide its Verification Tag (Tag_A) in the Initiate
	 * Tag field.  Tag_A SHOULD be a random number in the range of
	 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
	 */

	repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
	if (!repl)
		goto nomem;

	/* Cast away the const modifier, as we want to just
	 * rerun it through as a sideffect.
	 */
4516 4517
	my_asoc = (struct sctp_association *)asoc;
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
L
Linus Torvalds 已提交
4518

F
Frank Filz 已提交
4519 4520 4521 4522
	/* Choose transport for INIT. */
	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
			SCTP_CHUNK(repl));

L
Linus Torvalds 已提交
4523 4524 4525 4526 4527 4528 4529 4530 4531 4532 4533 4534 4535 4536 4537 4538 4539 4540 4541 4542 4543 4544 4545 4546 4547 4548 4549 4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601
	/* After sending the INIT, "A" starts the T1-init timer and
	 * enters the COOKIE-WAIT state.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
	return SCTP_DISPOSITION_CONSUME;

nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Process the SEND primitive.
 *
 * Section: 10.1 ULP-to-SCTP
 * E) Send
 *
 * Format: SEND(association id, buffer address, byte count [,context]
 *         [,stream id] [,life time] [,destination transport address]
 *         [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
 * -> result
 *
 * This is the main method to send user data via SCTP.
 *
 * Mandatory attributes:
 *
 *  o association id - local handle to the SCTP association
 *
 *  o buffer address - the location where the user message to be
 *    transmitted is stored;
 *
 *  o byte count - The size of the user data in number of bytes;
 *
 * Optional attributes:
 *
 *  o context - an optional 32 bit integer that will be carried in the
 *    sending failure notification to the ULP if the transportation of
 *    this User Message fails.
 *
 *  o stream id - to indicate which stream to send the data on. If not
 *    specified, stream 0 will be used.
 *
 *  o life time - specifies the life time of the user data. The user data
 *    will not be sent by SCTP after the life time expires. This
 *    parameter can be used to avoid efforts to transmit stale
 *    user messages. SCTP notifies the ULP if the data cannot be
 *    initiated to transport (i.e. sent to the destination via SCTP's
 *    send primitive) within the life time variable. However, the
 *    user data will be transmitted if SCTP has attempted to transmit a
 *    chunk before the life time expired.
 *
 *  o destination transport address - specified as one of the destination
 *    transport addresses of the peer endpoint to which this packet
 *    should be sent. Whenever possible, SCTP should use this destination
 *    transport address for sending the packets, instead of the current
 *    primary path.
 *
 *  o unorder flag - this flag, if present, indicates that the user
 *    would like the data delivered in an unordered fashion to the peer
 *    (i.e., the U flag is set to 1 on all DATA chunks carrying this
 *    message).
 *
 *  o no-bundle flag - instructs SCTP not to bundle this user data with
 *    other outbound DATA chunks. SCTP MAY still bundle even when
 *    this flag is present, when faced with network congestion.
 *
 *  o payload protocol-id - A 32 bit unsigned integer that is to be
 *    passed to the peer indicating the type of payload protocol data
 *    being transmitted. This value is passed as opaque data by SCTP.
 *
 * The return value is the disposition.
 */
sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep,
				       const struct sctp_association *asoc,
				       const sctp_subtype_t type,
				       void *arg,
				       sctp_cmd_seq_t *commands)
{
4602
	struct sctp_datamsg *msg = arg;
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4604
	sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
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4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 4648 4649 4650 4651 4652 4653 4654 4655 4656 4657 4658 4659 4660 4661 4662 4663 4664 4665 4666 4667 4668 4669 4670 4671 4672 4673 4674 4675 4676 4677 4678 4679 4680 4681 4682 4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698 4699 4700 4701 4702 4703
	return SCTP_DISPOSITION_CONSUME;
}

/*
 * Process the SHUTDOWN primitive.
 *
 * Section: 10.1:
 * C) Shutdown
 *
 * Format: SHUTDOWN(association id)
 * -> result
 *
 * Gracefully closes an association. Any locally queued user data
 * will be delivered to the peer. The association will be terminated only
 * after the peer acknowledges all the SCTP packets sent.  A success code
 * will be returned on successful termination of the association. If
 * attempting to terminate the association results in a failure, an error
 * code shall be returned.
 *
 * Mandatory attributes:
 *
 *  o association id - local handle to the SCTP association
 *
 * Optional attributes:
 *
 * None.
 *
 * The return value is the disposition.
 */
sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	int disposition;

	/* From 9.2 Shutdown of an Association
	 * Upon receipt of the SHUTDOWN primitive from its upper
	 * layer, the endpoint enters SHUTDOWN-PENDING state and
	 * remains there until all outstanding data has been
	 * acknowledged by its peer. The endpoint accepts no new data
	 * from its upper layer, but retransmits data to the far end
	 * if necessary to fill gaps.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));

	disposition = SCTP_DISPOSITION_CONSUME;
	if (sctp_outq_is_empty(&asoc->outqueue)) {
		disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
							    arg, commands);
	}
	return disposition;
}

/*
 * Process the ABORT primitive.
 *
 * Section: 10.1:
 * C) Abort
 *
 * Format: Abort(association id [, cause code])
 * -> result
 *
 * Ungracefully closes an association. Any locally queued user data
 * will be discarded and an ABORT chunk is sent to the peer.  A success code
 * will be returned on successful abortion of the association. If
 * attempting to abort the association results in a failure, an error
 * code shall be returned.
 *
 * Mandatory attributes:
 *
 *  o association id - local handle to the SCTP association
 *
 * Optional attributes:
 *
 *  o cause code - reason of the abort to be passed to the peer
 *
 * None.
 *
 * The return value is the disposition.
 */
sctp_disposition_t sctp_sf_do_9_1_prm_abort(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	/* From 9.1 Abort of an Association
	 * Upon receipt of the ABORT primitive from its upper
	 * layer, the endpoint enters CLOSED state and
	 * discard all outstanding data has been
	 * acknowledged by its peer. The endpoint accepts no new data
	 * from its upper layer, but retransmits data to the far end
	 * if necessary to fill gaps.
	 */
4704
	struct sctp_chunk *abort = arg;
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	sctp_disposition_t retval;

	retval = SCTP_DISPOSITION_CONSUME;

4709
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
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	/* Even if we can't send the ABORT due to low memory delete the
	 * TCB.  This is a departure from our typical NOMEM handling.
	 */

4715 4716
	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
			SCTP_ERROR(ECONNABORTED));
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	/* Delete the established association. */
	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4719
			SCTP_PERR(SCTP_ERROR_USER_ABORT));
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	SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
	SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);

	return retval;
}

/* We tried an illegal operation on an association which is closed.  */
sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
	return SCTP_DISPOSITION_CONSUME;
}

/* We tried an illegal operation on an association which is shutting
 * down.
 */
sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep,
					  const struct sctp_association *asoc,
					  const sctp_subtype_t type,
					  void *arg,
					  sctp_cmd_seq_t *commands)
{
	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
			SCTP_ERROR(-ESHUTDOWN));
	return SCTP_DISPOSITION_CONSUME;
}

/*
 * sctp_cookie_wait_prm_shutdown
 *
 * Section: 4 Note: 2
 * Verification Tag:
 * Inputs
 * (endpoint, asoc)
 *
 * The RFC does not explicitly address this issue, but is the route through the
 * state table when someone issues a shutdown while in COOKIE_WAIT state.
 *
 * Outputs
 * (timers)
 */
sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));

	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_CLOSED));

	SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);

	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());

	return SCTP_DISPOSITION_DELETE_TCB;
}

/*
 * sctp_cookie_echoed_prm_shutdown
 *
 * Section: 4 Note: 2
 * Verification Tag:
 * Inputs
 * (endpoint, asoc)
 *
 * The RFC does not explcitly address this issue, but is the route through the
 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
 *
 * Outputs
 * (timers)
 */
sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg, sctp_cmd_seq_t *commands)
{
	/* There is a single T1 timer, so we should be able to use
	 * common function with the COOKIE-WAIT state.
	 */
	return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands);
}

/*
 * sctp_sf_cookie_wait_prm_abort
 *
 * Section: 4 Note: 2
 * Verification Tag:
 * Inputs
 * (endpoint, asoc)
 *
 * The RFC does not explicitly address this issue, but is the route through the
 * state table when someone issues an abort while in COOKIE_WAIT state.
 *
 * Outputs
 * (timers)
 */
sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
4833
	struct sctp_chunk *abort = arg;
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4834 4835 4836 4837 4838 4839 4840
	sctp_disposition_t retval;

	/* Stop T1-init timer */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
	retval = SCTP_DISPOSITION_CONSUME;

4841
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
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4842 4843 4844 4845 4846 4847 4848 4849 4850 4851

	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_CLOSED));

	SCTP_INC_STATS(SCTP_MIB_ABORTEDS);

	/* Even if we can't send the ABORT due to low memory delete the
	 * TCB.  This is a departure from our typical NOMEM handling.
	 */

4852 4853
	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
			SCTP_ERROR(ECONNREFUSED));
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4854 4855
	/* Delete the established association. */
	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4856
			SCTP_PERR(SCTP_ERROR_USER_ABORT));
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	return retval;
}

/*
 * sctp_sf_cookie_echoed_prm_abort
 *
 * Section: 4 Note: 3
 * Verification Tag:
 * Inputs
 * (endpoint, asoc)
 *
 * The RFC does not explcitly address this issue, but is the route through the
 * state table when someone issues an abort while in COOKIE_ECHOED state.
 *
 * Outputs
 * (timers)
 */
sctp_disposition_t sctp_sf_cookie_echoed_prm_abort(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	/* There is a single T1 timer, so we should be able to use
	 * common function with the COOKIE-WAIT state.
	 */
	return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands);
}

/*
 * sctp_sf_shutdown_pending_prm_abort
 *
 * Inputs
 * (endpoint, asoc)
 *
 * The RFC does not explicitly address this issue, but is the route through the
 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
 *
 * Outputs
 * (timers)
 */
sctp_disposition_t sctp_sf_shutdown_pending_prm_abort(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	/* Stop the T5-shutdown guard timer.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));

	return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
}

/*
 * sctp_sf_shutdown_sent_prm_abort
 *
 * Inputs
 * (endpoint, asoc)
 *
 * The RFC does not explicitly address this issue, but is the route through the
 * state table when someone issues an abort while in SHUTDOWN-SENT state.
 *
 * Outputs
 * (timers)
 */
sctp_disposition_t sctp_sf_shutdown_sent_prm_abort(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	/* Stop the T2-shutdown timer.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));

	/* Stop the T5-shutdown guard timer.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));

	return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
}

/*
 * sctp_sf_cookie_echoed_prm_abort
 *
 * Inputs
 * (endpoint, asoc)
 *
 * The RFC does not explcitly address this issue, but is the route through the
 * state table when someone issues an abort while in COOKIE_ECHOED state.
 *
 * Outputs
 * (timers)
 */
sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	/* The same T2 timer, so we should be able to use
	 * common function with the SHUTDOWN-SENT state.
	 */
	return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands);
}

/*
 * Process the REQUESTHEARTBEAT primitive
 *
 * 10.1 ULP-to-SCTP
 * J) Request Heartbeat
 *
 * Format: REQUESTHEARTBEAT(association id, destination transport address)
 *
 * -> result
 *
 * Instructs the local endpoint to perform a HeartBeat on the specified
 * destination transport address of the given association. The returned
 * result should indicate whether the transmission of the HEARTBEAT
 * chunk to the destination address is successful.
 *
 * Mandatory attributes:
 *
 * o association id - local handle to the SCTP association
 *
 * o destination transport address - the transport address of the
 *   association on which a heartbeat should be issued.
 */
sctp_disposition_t sctp_sf_do_prm_requestheartbeat(
					const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
4998 4999 5000 5001 5002 5003 5004 5005 5006 5007 5008 5009 5010 5011 5012
	if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
				      (struct sctp_transport *)arg, commands))
		return SCTP_DISPOSITION_NOMEM;

	/*
	 * RFC 2960 (bis), section 8.3
	 *
	 *    D) Request an on-demand HEARTBEAT on a specific destination
	 *    transport address of a given association.
	 *
	 *    The endpoint should increment the respective error  counter of
	 *    the destination transport address each time a HEARTBEAT is sent
	 *    to that address and not acknowledged within one RTO.
	 *
	 */
5013
	sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5014 5015
			SCTP_TRANSPORT(arg));
	return SCTP_DISPOSITION_CONSUME;
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}

/*
 * ADDIP Section 4.1 ASCONF Chunk Procedures
 * When an endpoint has an ASCONF signaled change to be sent to the
 * remote endpoint it should do A1 to A9
 */
sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = arg;

	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
	return SCTP_DISPOSITION_CONSUME;
}

/*
 * Ignore the primitive event
 *
 * The return value is the disposition of the primitive.
 */
sctp_disposition_t sctp_sf_ignore_primitive(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive);
	return SCTP_DISPOSITION_DISCARD;
}

/***************************************************************************
 * These are the state functions for the OTHER events.
 ***************************************************************************/

/*
 * Start the shutdown negotiation.
 *
 * From Section 9.2:
 * Once all its outstanding data has been acknowledged, the endpoint
 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
 * TSN Ack field the last sequential TSN it has received from the peer.
 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
 * with the updated last sequential TSN received from its peer.
 *
 * The return value is the disposition.
 */
sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *reply;

	/* Once all its outstanding data has been acknowledged, the
	 * endpoint shall send a SHUTDOWN chunk to its peer including
	 * in the Cumulative TSN Ack field the last sequential TSN it
	 * has received from the peer.
	 */
	reply = sctp_make_shutdown(asoc, NULL);
	if (!reply)
		goto nomem;

	/* Set the transport for the SHUTDOWN chunk and the timeout for the
	 * T2-shutdown timer.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));

	/* It shall then start the T2-shutdown timer */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));

5098 5099 5100 5101 5102 5103 5104
	/* RFC 4960 Section 9.2
	 * The sender of the SHUTDOWN MAY also start an overall guard timer
	 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));

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	if (asoc->autoclose)
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));

	/* and enter the SHUTDOWN-SENT state.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));

	/* sctp-implguide 2.10 Issues with Heartbeating and failover
	 *
	 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5116
	 * or SHUTDOWN-ACK.
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	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());

	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));

	return SCTP_DISPOSITION_CONSUME;

nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Generate a SHUTDOWN ACK now that everything is SACK'd.
 *
 * From Section 9.2:
 *
 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
 * endpoint must re-send the SHUTDOWN ACK.
 *
 * The return value is the disposition.
 */
sctp_disposition_t sctp_sf_do_9_2_shutdown_ack(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
	struct sctp_chunk *reply;

	/* There are 2 ways of getting here:
	 *    1) called in response to a SHUTDOWN chunk
	 *    2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
	 *
	 * For the case (2), the arg parameter is set to NULL.  We need
	 * to check that we have a chunk before accessing it's fields.
	 */
	if (chunk) {
		if (!sctp_vtag_verify(chunk, asoc))
			return sctp_sf_pdiscard(ep, asoc, type, arg, commands);

		/* Make sure that the SHUTDOWN chunk has a valid length. */
		if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t)))
			return sctp_sf_violation_chunklen(ep, asoc, type, arg,
							  commands);
	}

	/* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
	 * shall send a SHUTDOWN ACK ...
	 */
	reply = sctp_make_shutdown_ack(asoc, chunk);
	if (!reply)
		goto nomem;

	/* Set the transport for the SHUTDOWN ACK chunk and the timeout for
	 * the T2-shutdown timer.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));

	/* and start/restart a T2-shutdown timer of its own, */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));

	if (asoc->autoclose)
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));

	/* Enter the SHUTDOWN-ACK-SENT state.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));

	/* sctp-implguide 2.10 Issues with Heartbeating and failover
	 *
	 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5194
	 * or SHUTDOWN-ACK.
L
Linus Torvalds 已提交
5195 5196 5197 5198 5199 5200 5201 5202 5203 5204 5205 5206 5207 5208 5209 5210 5211 5212 5213 5214 5215 5216 5217 5218 5219 5220 5221 5222 5223 5224 5225 5226 5227 5228 5229 5230 5231 5232 5233 5234 5235 5236 5237 5238 5239 5240 5241 5242 5243
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());

	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));

	return SCTP_DISPOSITION_CONSUME;

nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/*
 * Ignore the event defined as other
 *
 * The return value is the disposition of the event.
 */
sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other);
	return SCTP_DISPOSITION_DISCARD;
}

/************************************************************
 * These are the state functions for handling timeout events.
 ************************************************************/

/*
 * RTX Timeout
 *
 * Section: 6.3.3 Handle T3-rtx Expiration
 *
 * Whenever the retransmission timer T3-rtx expires for a destination
 * address, do the following:
 * [See below]
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	struct sctp_transport *transport = arg;

5244 5245
	SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS);

L
Linus Torvalds 已提交
5246
	if (asoc->overall_error_count >= asoc->max_retrans) {
5247 5248
		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
				SCTP_ERROR(ETIMEDOUT));
L
Linus Torvalds 已提交
5249 5250
		/* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5251
				SCTP_PERR(SCTP_ERROR_NO_ERROR));
L
Linus Torvalds 已提交
5252 5253 5254 5255 5256 5257 5258 5259 5260 5261 5262 5263 5264 5265 5266 5267 5268 5269 5270 5271 5272 5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286
		SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
		SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
		return SCTP_DISPOSITION_DELETE_TCB;
	}

	/* E1) For the destination address for which the timer
	 * expires, adjust its ssthresh with rules defined in Section
	 * 7.2.3 and set the cwnd <- MTU.
	 */

	/* E2) For the destination address for which the timer
	 * expires, set RTO <- RTO * 2 ("back off the timer").  The
	 * maximum value discussed in rule C7 above (RTO.max) may be
	 * used to provide an upper bound to this doubling operation.
	 */

	/* E3) Determine how many of the earliest (i.e., lowest TSN)
	 * outstanding DATA chunks for the address for which the
	 * T3-rtx has expired will fit into a single packet, subject
	 * to the MTU constraint for the path corresponding to the
	 * destination transport address to which the retransmission
	 * is being sent (this may be different from the address for
	 * which the timer expires [see Section 6.4]).  Call this
	 * value K. Bundle and retransmit those K DATA chunks in a
	 * single packet to the destination endpoint.
	 *
	 * Note: Any DATA chunks that were sent to the address for
	 * which the T3-rtx timer expired but did not fit in one MTU
	 * (rule E3 above), should be marked for retransmission and
	 * sent as soon as cwnd allows (normally when a SACK arrives).
	 */

	/* Do some failure management (Section 8.2). */
	sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));

5287 5288 5289
	/* NB: Rules E4 and F1 are implicit in R1.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));

L
Linus Torvalds 已提交
5290 5291 5292 5293 5294 5295 5296 5297 5298 5299 5300 5301 5302 5303 5304 5305 5306 5307 5308 5309 5310 5311 5312 5313
	return SCTP_DISPOSITION_CONSUME;
}

/*
 * Generate delayed SACK on timeout
 *
 * Section: 6.2  Acknowledgement on Reception of DATA Chunks
 *
 * The guidelines on delayed acknowledgement algorithm specified in
 * Section 4.2 of [RFC2581] SHOULD be followed.  Specifically, an
 * acknowledgement SHOULD be generated for at least every second packet
 * (not every second DATA chunk) received, and SHOULD be generated
 * within 200 ms of the arrival of any unacknowledged DATA chunk.  In
 * some situations it may be beneficial for an SCTP transmitter to be
 * more conservative than the algorithms detailed in this document
 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
 * the following algorithms allow.
 */
sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep,
				       const struct sctp_association *asoc,
				       const sctp_subtype_t type,
				       void *arg,
				       sctp_cmd_seq_t *commands)
{
5314
	SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS);
L
Linus Torvalds 已提交
5315 5316 5317 5318 5319
	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
	return SCTP_DISPOSITION_CONSUME;
}

/*
F
Frank Filz 已提交
5320
 * sctp_sf_t1_init_timer_expire
L
Linus Torvalds 已提交
5321 5322 5323 5324 5325 5326 5327 5328 5329 5330 5331 5332 5333
 *
 * Section: 4 Note: 2
 * Verification Tag:
 * Inputs
 * (endpoint, asoc)
 *
 *  RFC 2960 Section 4 Notes
 *  2) If the T1-init timer expires, the endpoint MUST retransmit INIT
 *     and re-start the T1-init timer without changing state.  This MUST
 *     be repeated up to 'Max.Init.Retransmits' times.  After that, the
 *     endpoint MUST abort the initialization process and report the
 *     error to SCTP user.
 *
F
Frank Filz 已提交
5334 5335 5336 5337 5338 5339 5340 5341 5342 5343 5344 5345 5346 5347 5348
 * Outputs
 * (timers, events)
 *
 */
sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep,
					   const struct sctp_association *asoc,
					   const sctp_subtype_t type,
					   void *arg,
					   sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *repl = NULL;
	struct sctp_bind_addr *bp;
	int attempts = asoc->init_err_counter + 1;

	SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n");
5349
	SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS);
F
Frank Filz 已提交
5350

5351
	if (attempts <= asoc->max_init_attempts) {
F
Frank Filz 已提交
5352 5353 5354 5355 5356 5357 5358 5359 5360 5361 5362 5363 5364 5365 5366 5367 5368 5369
		bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
		repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
		if (!repl)
			return SCTP_DISPOSITION_NOMEM;

		/* Choose transport for INIT. */
		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
				SCTP_CHUNK(repl));

		/* Issue a sideeffect to do the needed accounting. */
		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));

		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
	} else {
		SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d"
				  " max_init_attempts: %d\n",
				  attempts, asoc->max_init_attempts);
5370 5371
		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
				SCTP_ERROR(ETIMEDOUT));
F
Frank Filz 已提交
5372
		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5373
				SCTP_PERR(SCTP_ERROR_NO_ERROR));
F
Frank Filz 已提交
5374 5375 5376 5377 5378 5379 5380 5381 5382 5383 5384 5385 5386 5387 5388 5389
		return SCTP_DISPOSITION_DELETE_TCB;
	}

	return SCTP_DISPOSITION_CONSUME;
}

/*
 * sctp_sf_t1_cookie_timer_expire
 *
 * Section: 4 Note: 2
 * Verification Tag:
 * Inputs
 * (endpoint, asoc)
 *
 *  RFC 2960 Section 4 Notes
 *  3) If the T1-cookie timer expires, the endpoint MUST retransmit
L
Linus Torvalds 已提交
5390 5391 5392 5393 5394 5395 5396 5397 5398
 *     COOKIE ECHO and re-start the T1-cookie timer without changing
 *     state.  This MUST be repeated up to 'Max.Init.Retransmits' times.
 *     After that, the endpoint MUST abort the initialization process and
 *     report the error to SCTP user.
 *
 * Outputs
 * (timers, events)
 *
 */
F
Frank Filz 已提交
5399
sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep,
L
Linus Torvalds 已提交
5400 5401 5402 5403 5404
					   const struct sctp_association *asoc,
					   const sctp_subtype_t type,
					   void *arg,
					   sctp_cmd_seq_t *commands)
{
F
Frank Filz 已提交
5405 5406
	struct sctp_chunk *repl = NULL;
	int attempts = asoc->init_err_counter + 1;
L
Linus Torvalds 已提交
5407

F
Frank Filz 已提交
5408
	SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n");
5409
	SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS);
L
Linus Torvalds 已提交
5410

5411
	if (attempts <= asoc->max_init_attempts) {
F
Frank Filz 已提交
5412
		repl = sctp_make_cookie_echo(asoc, NULL);
L
Linus Torvalds 已提交
5413
		if (!repl)
F
Frank Filz 已提交
5414
			return SCTP_DISPOSITION_NOMEM;
L
Linus Torvalds 已提交
5415

5416 5417
		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
				SCTP_CHUNK(repl));
L
Linus Torvalds 已提交
5418
		/* Issue a sideeffect to do the needed accounting. */
F
Frank Filz 已提交
5419 5420 5421
		sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));

L
Linus Torvalds 已提交
5422 5423
		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
	} else {
5424 5425
		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
				SCTP_ERROR(ETIMEDOUT));
L
Linus Torvalds 已提交
5426
		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5427
				SCTP_PERR(SCTP_ERROR_NO_ERROR));
L
Linus Torvalds 已提交
5428 5429 5430 5431 5432 5433 5434 5435 5436 5437 5438 5439 5440 5441 5442 5443 5444 5445 5446 5447 5448 5449 5450 5451 5452 5453 5454 5455
		return SCTP_DISPOSITION_DELETE_TCB;
	}

	return SCTP_DISPOSITION_CONSUME;
}

/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
 * with the updated last sequential TSN received from its peer.
 *
 * An endpoint should limit the number of retransmissions of the
 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
 * If this threshold is exceeded the endpoint should destroy the TCB and
 * MUST report the peer endpoint unreachable to the upper layer (and
 * thus the association enters the CLOSED state).  The reception of any
 * packet from its peer (i.e. as the peer sends all of its queued DATA
 * chunks) should clear the endpoint's retransmission count and restart
 * the T2-Shutdown timer,  giving its peer ample opportunity to transmit
 * all of its queued DATA chunks that have not yet been sent.
 */
sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep,
					   const struct sctp_association *asoc,
					   const sctp_subtype_t type,
					   void *arg,
					   sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *reply = NULL;

	SCTP_DEBUG_PRINTK("Timer T2 expired.\n");
5456 5457
	SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS);

5458 5459
	((struct sctp_association *)asoc)->shutdown_retries++;

L
Linus Torvalds 已提交
5460
	if (asoc->overall_error_count >= asoc->max_retrans) {
5461 5462
		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
				SCTP_ERROR(ETIMEDOUT));
L
Linus Torvalds 已提交
5463 5464
		/* Note:  CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5465
				SCTP_PERR(SCTP_ERROR_NO_ERROR));
L
Linus Torvalds 已提交
5466 5467 5468 5469 5470 5471 5472 5473 5474 5475 5476 5477 5478 5479 5480 5481 5482
		SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
		SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
		return SCTP_DISPOSITION_DELETE_TCB;
	}

	switch (asoc->state) {
	case SCTP_STATE_SHUTDOWN_SENT:
		reply = sctp_make_shutdown(asoc, NULL);
		break;

	case SCTP_STATE_SHUTDOWN_ACK_SENT:
		reply = sctp_make_shutdown_ack(asoc, NULL);
		break;

	default:
		BUG();
		break;
5483
	}
L
Linus Torvalds 已提交
5484 5485 5486 5487

	if (!reply)
		goto nomem;

5488 5489 5490 5491 5492 5493 5494
	/* Do some failure management (Section 8.2).
	 * If we remove the transport an SHUTDOWN was last sent to, don't
	 * do failure management.
	 */
	if (asoc->shutdown_last_sent_to)
		sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
				SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
L
Linus Torvalds 已提交
5495 5496 5497 5498 5499 5500 5501 5502 5503 5504 5505 5506 5507 5508 5509 5510 5511 5512 5513 5514 5515 5516 5517 5518 5519 5520 5521 5522 5523 5524

	/* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
	 * the T2-shutdown timer.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));

	/* Restart the T2-shutdown timer.  */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
	return SCTP_DISPOSITION_CONSUME;

nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/*
 * ADDIP Section 4.1 ASCONF CHunk Procedures
 * If the T4 RTO timer expires the endpoint should do B1 to B5
 */
sctp_disposition_t sctp_sf_t4_timer_expire(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *chunk = asoc->addip_last_asconf;
	struct sctp_transport *transport = chunk->transport;

5525 5526
	SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS);

L
Linus Torvalds 已提交
5527 5528 5529 5530
	/* ADDIP 4.1 B1) Increment the error counters and perform path failure
	 * detection on the appropriate destination address as defined in
	 * RFC2960 [5] section 8.1 and 8.2.
	 */
5531 5532 5533
	if (transport)
		sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
				SCTP_TRANSPORT(transport));
L
Linus Torvalds 已提交
5534 5535 5536 5537 5538 5539 5540 5541 5542 5543 5544 5545

	/* Reconfig T4 timer and transport. */
	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));

	/* ADDIP 4.1 B2) Increment the association error counters and perform
	 * endpoint failure detection on the association as defined in
	 * RFC2960 [5] section 8.1 and 8.2.
	 * association error counter is incremented in SCTP_CMD_STRIKE.
	 */
	if (asoc->overall_error_count >= asoc->max_retrans) {
		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5546 5547
		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
				SCTP_ERROR(ETIMEDOUT));
L
Linus Torvalds 已提交
5548
		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5549
				SCTP_PERR(SCTP_ERROR_NO_ERROR));
L
Linus Torvalds 已提交
5550
		SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5551
		SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
L
Linus Torvalds 已提交
5552 5553 5554 5555 5556 5557 5558 5559 5560 5561 5562
		return SCTP_DISPOSITION_ABORT;
	}

	/* ADDIP 4.1 B3) Back-off the destination address RTO value to which
	 * the ASCONF chunk was sent by doubling the RTO timer value.
	 * This is done in SCTP_CMD_STRIKE.
	 */

	/* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
	 * choose an alternate destination address (please refer to RFC2960
	 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5563
	 * chunk, it MUST be the same (including its serial number) as the last
L
Linus Torvalds 已提交
5564 5565 5566 5567 5568 5569 5570 5571 5572 5573 5574 5575 5576 5577 5578 5579 5580 5581 5582 5583 5584 5585 5586 5587 5588 5589 5590 5591 5592 5593 5594
	 * ASCONF sent.
	 */
	sctp_chunk_hold(asoc->addip_last_asconf);
	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
			SCTP_CHUNK(asoc->addip_last_asconf));

	/* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
	 * destination is selected, then the RTO used will be that of the new
	 * destination address.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));

	return SCTP_DISPOSITION_CONSUME;
}

/* sctpimpguide-05 Section 2.12.2
 * The sender of the SHUTDOWN MAY also start an overall guard timer
 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
 * At the expiration of this timer the sender SHOULD abort the association
 * by sending an ABORT chunk.
 */
sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep,
					   const struct sctp_association *asoc,
					   const sctp_subtype_t type,
					   void *arg,
					   sctp_cmd_seq_t *commands)
{
	struct sctp_chunk *reply = NULL;

	SCTP_DEBUG_PRINTK("Timer T5 expired.\n");
5595
	SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
L
Linus Torvalds 已提交
5596 5597 5598 5599 5600 5601

	reply = sctp_make_abort(asoc, NULL, 0);
	if (!reply)
		goto nomem;

	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5602 5603
	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
			SCTP_ERROR(ETIMEDOUT));
L
Linus Torvalds 已提交
5604
	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5605
			SCTP_PERR(SCTP_ERROR_NO_ERROR));
L
Linus Torvalds 已提交
5606

5607 5608 5609
	SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
	SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);

L
Linus Torvalds 已提交
5610 5611 5612 5613 5614 5615 5616 5617 5618 5619 5620 5621 5622 5623 5624 5625 5626 5627 5628
	return SCTP_DISPOSITION_DELETE_TCB;
nomem:
	return SCTP_DISPOSITION_NOMEM;
}

/* Handle expiration of AUTOCLOSE timer.  When the autoclose timer expires,
 * the association is automatically closed by starting the shutdown process.
 * The work that needs to be done is same as when SHUTDOWN is initiated by
 * the user.  So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
 */
sctp_disposition_t sctp_sf_autoclose_timer_expire(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	const sctp_subtype_t type,
	void *arg,
	sctp_cmd_seq_t *commands)
{
	int disposition;

5629 5630
	SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS);

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Linus Torvalds 已提交
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	/* From 9.2 Shutdown of an Association
	 * Upon receipt of the SHUTDOWN primitive from its upper
	 * layer, the endpoint enters SHUTDOWN-PENDING state and
	 * remains there until all outstanding data has been
	 * acknowledged by its peer. The endpoint accepts no new data
	 * from its upper layer, but retransmits data to the far end
	 * if necessary to fill gaps.
	 */
	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
			SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));

	disposition = SCTP_DISPOSITION_CONSUME;
	if (sctp_outq_is_empty(&asoc->outqueue)) {
		disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
							    arg, commands);
	}
	return disposition;
}

/*****************************************************************************
 * These are sa state functions which could apply to all types of events.
 ****************************************************************************/

/*
 * This table entry is not implemented.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep,
				    const struct sctp_association *asoc,
				    const sctp_subtype_t type,
				    void *arg,
				    sctp_cmd_seq_t *commands)
{
	return SCTP_DISPOSITION_NOT_IMPL;
}

/*
 * This table entry represents a bug.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep,
			       const struct sctp_association *asoc,
			       const sctp_subtype_t type,
			       void *arg,
			       sctp_cmd_seq_t *commands)
{
	return SCTP_DISPOSITION_BUG;
}

/*
 * This table entry represents the firing of a timer in the wrong state.
 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
 * when the association is in the wrong state.   This event should
 * be ignored, so as to prevent any rearming of the timer.
 *
 * Inputs
 * (endpoint, asoc, chunk)
 *
 * The return value is the disposition of the chunk.
 */
sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const sctp_subtype_t type,
					void *arg,
					sctp_cmd_seq_t *commands)
{
	SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk);
	return SCTP_DISPOSITION_CONSUME;
}

/********************************************************************
 * 2nd Level Abstractions
 ********************************************************************/

/* Pull the SACK chunk based on the SACK header. */
static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
{
	struct sctp_sackhdr *sack;
	unsigned int len;
	__u16 num_blocks;
	__u16 num_dup_tsns;

	/* Protect ourselves from reading too far into
	 * the skb from a bogus sender.
	 */
	sack = (struct sctp_sackhdr *) chunk->skb->data;

	num_blocks = ntohs(sack->num_gap_ack_blocks);
	num_dup_tsns = ntohs(sack->num_dup_tsns);
	len = sizeof(struct sctp_sackhdr);
	len += (num_blocks + num_dup_tsns) * sizeof(__u32);
	if (len > chunk->skb->len)
		return NULL;

	skb_pull(chunk->skb, len);

	return sack;
}

/* Create an ABORT packet to be sent as a response, with the specified
 * error causes.
 */
static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
				  const struct sctp_association *asoc,
				  struct sctp_chunk *chunk,
				  const void *payload,
				  size_t paylen)
{
	struct sctp_packet *packet;
	struct sctp_chunk *abort;

	packet = sctp_ootb_pkt_new(asoc, chunk);

	if (packet) {
		/* Make an ABORT.
		 * The T bit will be set if the asoc is NULL.
		 */
		abort = sctp_make_abort(asoc, chunk, paylen);
		if (!abort) {
			sctp_ootb_pkt_free(packet);
			return NULL;
		}
5761 5762 5763 5764 5765

		/* Reflect vtag if T-Bit is set */
		if (sctp_test_T_bit(abort))
			packet->vtag = ntohl(chunk->sctp_hdr->vtag);

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		/* Add specified error causes, i.e., payload, to the
		 * end of the chunk.
		 */
		sctp_addto_chunk(abort, paylen, payload);

		/* Set the skb to the belonging sock for accounting.  */
		abort->skb->sk = ep->base.sk;

		sctp_packet_append_chunk(packet, abort);

	}

	return packet;
}

/* Allocate a packet for responding in the OOTB conditions.  */
static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
					     const struct sctp_chunk *chunk)
{
	struct sctp_packet *packet;
	struct sctp_transport *transport;
	__u16 sport;
	__u16 dport;
	__u32 vtag;

	/* Get the source and destination port from the inbound packet.  */
	sport = ntohs(chunk->sctp_hdr->dest);
	dport = ntohs(chunk->sctp_hdr->source);

	/* The V-tag is going to be the same as the inbound packet if no
	 * association exists, otherwise, use the peer's vtag.
	 */
	if (asoc) {
5799 5800 5801 5802 5803 5804 5805 5806 5807 5808 5809 5810 5811 5812 5813 5814
		/* Special case the INIT-ACK as there is no peer's vtag
		 * yet.
		 */
		switch(chunk->chunk_hdr->type) {
		case SCTP_CID_INIT_ACK:
		{
			sctp_initack_chunk_t *initack;

			initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
			vtag = ntohl(initack->init_hdr.init_tag);
			break;
		}
		default:
			vtag = asoc->peer.i.init_tag;
			break;
		}
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	} else {
		/* Special case the INIT and stale COOKIE_ECHO as there is no
		 * vtag yet.
		 */
		switch(chunk->chunk_hdr->type) {
		case SCTP_CID_INIT:
		{
			sctp_init_chunk_t *init;

			init = (sctp_init_chunk_t *)chunk->chunk_hdr;
			vtag = ntohl(init->init_hdr.init_tag);
			break;
		}
5828
		default:
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			vtag = ntohl(chunk->sctp_hdr->vtag);
			break;
		}
	}

	/* Make a transport for the bucket, Eliza... */
5835
	transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC);
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	if (!transport)
		goto nomem;

	/* Cache a route for the transport with the chunk's destination as
	 * the source address.
	 */
5842
	sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
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			     sctp_sk(sctp_get_ctl_sock()));

	packet = sctp_packet_init(&transport->packet, transport, sport, dport);
	packet = sctp_packet_config(packet, vtag, 0);

	return packet;

nomem:
	return NULL;
}

/* Free the packet allocated earlier for responding in the OOTB condition.  */
void sctp_ootb_pkt_free(struct sctp_packet *packet)
{
	sctp_transport_free(packet->transport);
}

/* Send a stale cookie error when a invalid COOKIE ECHO chunk is found  */
static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
				       const struct sctp_association *asoc,
				       const struct sctp_chunk *chunk,
				       sctp_cmd_seq_t *commands,
				       struct sctp_chunk *err_chunk)
{
	struct sctp_packet *packet;

	if (err_chunk) {
		packet = sctp_ootb_pkt_new(asoc, chunk);
		if (packet) {
			struct sctp_signed_cookie *cookie;

			/* Override the OOTB vtag from the cookie. */
			cookie = chunk->subh.cookie_hdr;
			packet->vtag = cookie->c.peer_vtag;
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			/* Set the skb to the belonging sock for accounting. */
			err_chunk->skb->sk = ep->base.sk;
			sctp_packet_append_chunk(packet, err_chunk);
			sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
					SCTP_PACKET(packet));
			SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
		} else
			sctp_chunk_free (err_chunk);
	}
}


/* Process a data chunk */
static int sctp_eat_data(const struct sctp_association *asoc,
			 struct sctp_chunk *chunk,
			 sctp_cmd_seq_t *commands)
{
	sctp_datahdr_t *data_hdr;
	struct sctp_chunk *err;
	size_t datalen;
	sctp_verb_t deliver;
	int tmp;
	__u32 tsn;
5901
	struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
5902
	struct sock *sk = asoc->base.sk;
5903 5904 5905
	u16 ssn;
	u16 sid;
	u8 ordered = 0;
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	data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
	skb_pull(chunk->skb, sizeof(sctp_datahdr_t));

	tsn = ntohl(data_hdr->tsn);
	SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn);

	/* ASSERT:  Now skb->data is really the user data.  */

	/* Process ECN based congestion.
	 *
	 * Since the chunk structure is reused for all chunks within
	 * a packet, we use ecn_ce_done to track if we've already
	 * done CE processing for this packet.
	 *
	 * We need to do ECN processing even if we plan to discard the
	 * chunk later.
	 */

	if (!chunk->ecn_ce_done) {
		struct sctp_af *af;
		chunk->ecn_ce_done = 1;

		af = sctp_get_af_specific(
5930
			ipver2af(ip_hdr(chunk->skb)->version));
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		if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) {
			/* Do real work as sideffect. */
			sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
					SCTP_U32(tsn));
		}
	}

	tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
	if (tmp < 0) {
		/* The TSN is too high--silently discard the chunk and
		 * count on it getting retransmitted later.
		 */
		return SCTP_IERROR_HIGH_TSN;
	} else if (tmp > 0) {
		/* This is a duplicate.  Record it.  */
		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
		return SCTP_IERROR_DUP_TSN;
	}

	/* This is a new TSN.  */

	/* Discard if there is no room in the receive window.
	 * Actually, allow a little bit of overflow (up to a MTU).
	 */
	datalen = ntohs(chunk->chunk_hdr->length);
	datalen -= sizeof(sctp_data_chunk_t);

	deliver = SCTP_CMD_CHUNK_ULP;

	/* Think about partial delivery. */
	if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {

		/* Even if we don't accept this chunk there is
		 * memory pressure.
		 */
		sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
	}

5970
	/* Spill over rwnd a little bit.  Note: While allowed, this spill over
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	 * seems a bit troublesome in that frag_point varies based on
	 * PMTU.  In cases, such as loopback, this might be a rather
	 * large spill over.
5974 5975 5976
	 */
	if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
	    (datalen > asoc->rwnd + asoc->frag_point))) {
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		/* If this is the next TSN, consider reneging to make
		 * room.   Note: Playing nice with a confused sender.  A
		 * malicious sender can still eat up all our buffer
		 * space and in the future we may want to detect and
		 * do more drastic reneging.
		 */
5984 5985
		if (sctp_tsnmap_has_gap(map) &&
		    (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
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			SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn);
			deliver = SCTP_CMD_RENEGE;
		} else {
			SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, "
					  "rwnd: %d\n", tsn, datalen,
					  asoc->rwnd);
			return SCTP_IERROR_IGNORE_TSN;
		}
	}

5996 5997 5998
	/*
	 * Also try to renege to limit our memory usage in the event that
	 * we are under memory pressure
5999
	 * If we can't renege, don't worry about it, the sk_rmem_schedule
6000 6001 6002 6003 6004 6005 6006 6007 6008 6009 6010
	 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
	 * memory usage too much
	 */
	if (*sk->sk_prot_creator->memory_pressure) {
		if (sctp_tsnmap_has_gap(map) &&
	           (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
			SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn);
			deliver = SCTP_CMD_RENEGE;
		 }
	}

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	/*
	 * Section 3.3.10.9 No User Data (9)
	 *
	 * Cause of error
	 * ---------------
	 * No User Data:  This error cause is returned to the originator of a
	 * DATA chunk if a received DATA chunk has no user data.
	 */
	if (unlikely(0 == datalen)) {
		err = sctp_make_abort_no_data(asoc, chunk, tsn);
		if (err) {
			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
					SCTP_CHUNK(err));
		}
		/* We are going to ABORT, so we might as well stop
		 * processing the rest of the chunks in the packet.
		 */
		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
6029 6030
		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
				SCTP_ERROR(ECONNABORTED));
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		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6032
				SCTP_PERR(SCTP_ERROR_NO_DATA));
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		SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
		SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
		return SCTP_IERROR_NO_DATA;
	}

6038 6039
	chunk->data_accepted = 1;

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	/* Note: Some chunks may get overcounted (if we drop) or overcounted
	 * if we renege and the chunk arrives again.
	 */
	if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
		SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS);
6045
	else {
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		SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS);
6047 6048
		ordered = 1;
	}
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	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
	 *
	 * If an endpoint receive a DATA chunk with an invalid stream
	 * identifier, it shall acknowledge the reception of the DATA chunk
	 * following the normal procedure, immediately send an ERROR chunk
	 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
	 * and discard the DATA chunk.
	 */
6058 6059
	sid = ntohs(data_hdr->stream);
	if (sid >= asoc->c.sinit_max_instreams) {
6060 6061 6062
		/* Mark tsn as received even though we drop it */
		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));

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		err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
					 &data_hdr->stream,
6065 6066
					 sizeof(data_hdr->stream),
					 sizeof(u16));
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		if (err)
			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
					SCTP_CHUNK(err));
		return SCTP_IERROR_BAD_STREAM;
	}

6073 6074 6075 6076 6077 6078 6079 6080 6081 6082 6083 6084
	/* Check to see if the SSN is possible for this TSN.
	 * The biggest gap we can record is 4K wide.  Since SSNs wrap
	 * at an unsigned short, there is no way that an SSN can
	 * wrap and for a valid TSN.  We can simply check if the current
	 * SSN is smaller then the next expected one.  If it is, it wrapped
	 * and is invalid.
	 */
	ssn = ntohs(data_hdr->ssn);
	if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) {
		return SCTP_IERROR_PROTO_VIOLATION;
	}

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	/* Send the data up to the user.  Note:  Schedule  the
	 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
	 * chunk needs the updated rwnd.
	 */
	sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));

	return SCTP_IERROR_NO_ERROR;
}