call_accept.c 11.7 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11
/* incoming call handling
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; 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 of the License, or (at your option) any later version.
 */

12 13
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

14 15 16 17 18 19 20 21
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/errqueue.h>
#include <linux/udp.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/icmp.h>
22
#include <linux/gfp.h>
23 24 25 26 27 28 29 30 31
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include "ar-internal.h"

/*
 * generate a connection-level abort
 */
static int rxrpc_busy(struct rxrpc_local *local, struct sockaddr_rxrpc *srx,
32
		      struct rxrpc_wire_header *whdr)
33 34 35 36 37 38 39 40
{
	struct msghdr msg;
	struct kvec iov[1];
	size_t len;
	int ret;

	_enter("%d,,", local->debug_id);

41 42 43
	whdr->type	= RXRPC_PACKET_TYPE_BUSY;
	whdr->serial	= htonl(1);

44 45 46 47 48 49
	msg.msg_name	= &srx->transport.sin;
	msg.msg_namelen	= sizeof(srx->transport.sin);
	msg.msg_control	= NULL;
	msg.msg_controllen = 0;
	msg.msg_flags	= 0;

50 51
	iov[0].iov_base	= whdr;
	iov[0].iov_len	= sizeof(*whdr);
52 53 54

	len = iov[0].iov_len;

55
	_proto("Tx BUSY %%1");
56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87

	ret = kernel_sendmsg(local->socket, &msg, iov, 1, len);
	if (ret < 0) {
		_leave(" = -EAGAIN [sendmsg failed: %d]", ret);
		return -EAGAIN;
	}

	_leave(" = 0");
	return 0;
}

/*
 * accept an incoming call that needs peer, transport and/or connection setting
 * up
 */
static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
				      struct rxrpc_sock *rx,
				      struct sk_buff *skb,
				      struct sockaddr_rxrpc *srx)
{
	struct rxrpc_connection *conn;
	struct rxrpc_skb_priv *sp, *nsp;
	struct rxrpc_call *call;
	struct sk_buff *notification;
	int ret;

	_enter("");

	sp = rxrpc_skb(skb);

	/* get a notification message to send to the server app */
	notification = alloc_skb(0, GFP_NOFS);
T
Tetsuo Handa 已提交
88 89 90 91 92
	if (!notification) {
		_debug("no memory");
		ret = -ENOMEM;
		goto error_nofree;
	}
93 94 95
	rxrpc_new_skb(notification);
	notification->mark = RXRPC_SKB_MARK_NEW_CALL;

96
	conn = rxrpc_incoming_connection(local, srx, skb);
97 98 99 100 101 102
	if (IS_ERR(conn)) {
		_debug("no conn");
		ret = PTR_ERR(conn);
		goto error;
	}

103
	call = rxrpc_incoming_call(rx, conn, skb);
104 105 106 107 108 109 110 111 112 113 114 115 116 117
	rxrpc_put_connection(conn);
	if (IS_ERR(call)) {
		_debug("no call");
		ret = PTR_ERR(call);
		goto error;
	}

	/* attach the call to the socket */
	read_lock_bh(&local->services_lock);
	if (rx->sk.sk_state == RXRPC_CLOSE)
		goto invalid_service;

	write_lock(&rx->call_lock);
	if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
118
		rxrpc_get_call(call, rxrpc_call_got);
119 120 121

		spin_lock(&call->conn->state_lock);
		if (sp->hdr.securityIndex > 0 &&
122
		    call->conn->state == RXRPC_CONN_SERVICE_UNSECURED) {
123 124
			_debug("await conn sec");
			list_add_tail(&call->accept_link, &rx->secureq);
125 126
			call->conn->state = RXRPC_CONN_SERVICE_CHALLENGING;
			set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events);
127
			rxrpc_queue_conn(call->conn);
128 129 130 131
		} else {
			_debug("conn ready");
			call->state = RXRPC_CALL_SERVER_ACCEPTING;
			list_add_tail(&call->accept_link, &rx->acceptq);
D
David Howells 已提交
132
			rxrpc_get_call_for_skb(call, notification);
133 134 135 136 137 138 139 140 141 142 143
			nsp = rxrpc_skb(notification);
			nsp->call = call;

			ASSERTCMP(atomic_read(&call->usage), >=, 3);

			_debug("notify");
			spin_lock(&call->lock);
			ret = rxrpc_queue_rcv_skb(call, notification, true,
						  false);
			spin_unlock(&call->lock);
			notification = NULL;
J
Julia Lawall 已提交
144
			BUG_ON(ret < 0);
145 146 147 148 149 150 151 152 153 154 155 156 157
		}
		spin_unlock(&call->conn->state_lock);

		_debug("queued");
	}
	write_unlock(&rx->call_lock);

	_debug("process");
	rxrpc_fast_process_packet(call, skb);

	_debug("done");
	read_unlock_bh(&local->services_lock);
	rxrpc_free_skb(notification);
158
	rxrpc_put_call(call, rxrpc_call_put);
159 160 161 162 163 164 165 166
	_leave(" = 0");
	return 0;

invalid_service:
	_debug("invalid");
	read_unlock_bh(&local->services_lock);

	read_lock_bh(&call->state_lock);
167
	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
168
	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
169
		rxrpc_get_call(call, rxrpc_call_got);
170
		rxrpc_queue_call(call);
171 172
	}
	read_unlock_bh(&call->state_lock);
173
	rxrpc_put_call(call, rxrpc_call_put);
174 175 176
	ret = -ECONNREFUSED;
error:
	rxrpc_free_skb(notification);
T
Tetsuo Handa 已提交
177
error_nofree:
178 179 180 181 182 183 184 185
	_leave(" = %d", ret);
	return ret;
}

/*
 * accept incoming calls that need peer, transport and/or connection setting up
 * - the packets we get are all incoming client DATA packets that have seq == 1
 */
186
void rxrpc_accept_incoming_calls(struct rxrpc_local *local)
187 188 189 190
{
	struct rxrpc_skb_priv *sp;
	struct sockaddr_rxrpc srx;
	struct rxrpc_sock *rx;
191
	struct rxrpc_wire_header whdr;
192 193 194 195 196 197 198 199 200 201 202 203 204
	struct sk_buff *skb;
	int ret;

	_enter("%d", local->debug_id);

	skb = skb_dequeue(&local->accept_queue);
	if (!skb) {
		_leave("\n");
		return;
	}

	_net("incoming call skb %p", skb);

205
	rxrpc_see_skb(skb);
206 207
	sp = rxrpc_skb(skb);

208 209 210 211 212 213 214 215 216 217 218 219 220
	/* Set up a response packet header in case we need it */
	whdr.epoch	= htonl(sp->hdr.epoch);
	whdr.cid	= htonl(sp->hdr.cid);
	whdr.callNumber	= htonl(sp->hdr.callNumber);
	whdr.seq	= htonl(sp->hdr.seq);
	whdr.serial	= 0;
	whdr.flags	= 0;
	whdr.type	= 0;
	whdr.userStatus	= 0;
	whdr.securityIndex = sp->hdr.securityIndex;
	whdr._rsvd	= 0;
	whdr.serviceId	= htons(sp->hdr.serviceId);

221 222
	if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
		goto drop;
223 224 225 226

	/* get the socket providing the service */
	read_lock_bh(&local->services_lock);
	list_for_each_entry(rx, &local->services, listen_link) {
227
		if (rx->srx.srx_service == sp->hdr.serviceId &&
228 229 230 231 232 233 234
		    rx->sk.sk_state != RXRPC_CLOSE)
			goto found_service;
	}
	read_unlock_bh(&local->services_lock);
	goto invalid_service;

found_service:
235
	_debug("found service %hd", rx->srx.srx_service);
236 237 238 239 240 241 242 243 244 245 246 247 248 249
	if (sk_acceptq_is_full(&rx->sk))
		goto backlog_full;
	sk_acceptq_added(&rx->sk);
	sock_hold(&rx->sk);
	read_unlock_bh(&local->services_lock);

	ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
	if (ret < 0)
		sk_acceptq_removed(&rx->sk);
	sock_put(&rx->sk);
	switch (ret) {
	case -ECONNRESET: /* old calls are ignored */
	case -ECONNABORTED: /* aborted calls are reaborted or ignored */
	case 0:
250
		return;
251 252 253 254 255 256 257 258 259 260 261 262 263
	case -ECONNREFUSED:
		goto invalid_service;
	case -EBUSY:
		goto busy;
	case -EKEYREJECTED:
		goto security_mismatch;
	default:
		BUG();
	}

backlog_full:
	read_unlock_bh(&local->services_lock);
busy:
264
	rxrpc_busy(local, &srx, &whdr);
265
	rxrpc_free_skb(skb);
266
	return;
267

268 269 270 271
drop:
	rxrpc_free_skb(skb);
	return;

272 273 274
invalid_service:
	skb->priority = RX_INVALID_OPERATION;
	rxrpc_reject_packet(local, skb);
275
	return;
276 277 278 279 280

	/* can't change connection security type mid-flow */
security_mismatch:
	skb->priority = RX_PROTOCOL_ERROR;
	rxrpc_reject_packet(local, skb);
281
	return;
282 283 284 285 286 287
}

/*
 * handle acceptance of a call by userspace
 * - assign the user call ID to the call at the front of the queue
 */
288
struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
289 290
				     unsigned long user_call_ID,
				     rxrpc_notify_rx_t notify_rx)
291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325
{
	struct rxrpc_call *call;
	struct rb_node *parent, **pp;
	int ret;

	_enter(",%lx", user_call_ID);

	ASSERT(!irqs_disabled());

	write_lock(&rx->call_lock);

	ret = -ENODATA;
	if (list_empty(&rx->acceptq))
		goto out;

	/* check the user ID isn't already in use */
	ret = -EBADSLT;
	pp = &rx->calls.rb_node;
	parent = NULL;
	while (*pp) {
		parent = *pp;
		call = rb_entry(parent, struct rxrpc_call, sock_node);

		if (user_call_ID < call->user_call_ID)
			pp = &(*pp)->rb_left;
		else if (user_call_ID > call->user_call_ID)
			pp = &(*pp)->rb_right;
		else
			goto out;
	}

	/* dequeue the first call and check it's still valid */
	call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
	list_del_init(&call->accept_link);
	sk_acceptq_removed(&rx->sk);
D
David Howells 已提交
326
	rxrpc_see_call(call);
327 328 329 330 331 332

	write_lock_bh(&call->state_lock);
	switch (call->state) {
	case RXRPC_CALL_SERVER_ACCEPTING:
		call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
		break;
333 334
	case RXRPC_CALL_COMPLETE:
		ret = call->error;
335 336 337 338 339 340 341 342 343
		goto out_release;
	case RXRPC_CALL_DEAD:
		ret = -ETIME;
		goto out_discard;
	default:
		BUG();
	}

	/* formalise the acceptance */
344
	rxrpc_get_call(call, rxrpc_call_got_userid);
345
	call->notify_rx = notify_rx;
346 347 348 349 350
	call->user_call_ID = user_call_ID;
	rb_link_node(&call->sock_node, parent, pp);
	rb_insert_color(&call->sock_node, &rx->calls);
	if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
		BUG();
351
	if (test_and_set_bit(RXRPC_CALL_EV_ACCEPTED, &call->events))
352
		BUG();
353
	rxrpc_queue_call(call);
354 355 356

	write_unlock_bh(&call->state_lock);
	write_unlock(&rx->call_lock);
357 358 359 360 361 362 363 364 365
	_leave(" = %p{%d}", call, call->debug_id);
	return call;

	/* if the call is already dying or dead, then we leave the socket's ref
	 * on it to be released by rxrpc_dead_call_expired() as induced by
	 * rxrpc_release_call() */
out_release:
	_debug("release %p", call);
	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
366
	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
367 368 369 370 371 372 373 374 375 376 377
		rxrpc_queue_call(call);
out_discard:
	write_unlock_bh(&call->state_lock);
	_debug("discard %p", call);
out:
	write_unlock(&rx->call_lock);
	_leave(" = %d", ret);
	return ERR_PTR(ret);
}

/*
378
 * Handle rejection of a call by userspace
379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399
 * - reject the call at the front of the queue
 */
int rxrpc_reject_call(struct rxrpc_sock *rx)
{
	struct rxrpc_call *call;
	int ret;

	_enter("");

	ASSERT(!irqs_disabled());

	write_lock(&rx->call_lock);

	ret = -ENODATA;
	if (list_empty(&rx->acceptq))
		goto out;

	/* dequeue the first call and check it's still valid */
	call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
	list_del_init(&call->accept_link);
	sk_acceptq_removed(&rx->sk);
D
David Howells 已提交
400
	rxrpc_see_call(call);
401 402 403 404

	write_lock_bh(&call->state_lock);
	switch (call->state) {
	case RXRPC_CALL_SERVER_ACCEPTING:
405 406
		__rxrpc_set_call_completion(call, RXRPC_CALL_SERVER_BUSY,
					    0, ECONNABORTED);
407
		if (test_and_set_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events))
408 409 410
			rxrpc_queue_call(call);
		ret = 0;
		goto out_release;
411 412
	case RXRPC_CALL_COMPLETE:
		ret = call->error;
413 414 415 416 417 418 419
		goto out_release;
	case RXRPC_CALL_DEAD:
		ret = -ETIME;
		goto out_discard;
	default:
		BUG();
	}
420 421 422 423 424 425 426

	/* if the call is already dying or dead, then we leave the socket's ref
	 * on it to be released by rxrpc_dead_call_expired() as induced by
	 * rxrpc_release_call() */
out_release:
	_debug("release %p", call);
	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
427
	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
428
		rxrpc_queue_call(call);
429 430 431 432 433 434 435 436
out_discard:
	write_unlock_bh(&call->state_lock);
	_debug("discard %p", call);
out:
	write_unlock(&rx->call_lock);
	_leave(" = %d", ret);
	return ret;
}
437 438 439 440 441

/**
 * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
 * @sock: The socket on which the impending call is waiting
 * @user_call_ID: The tag to attach to the call
442
 * @notify_rx: Where to send notifications instead of socket queue
443 444
 *
 * Allow a kernel service to accept an incoming call, assuming the incoming
445 446
 * call is still valid.  The caller should immediately trigger their own
 * notification as there must be data waiting.
447 448
 */
struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
449 450
					    unsigned long user_call_ID,
					    rxrpc_notify_rx_t notify_rx)
451 452 453 454
{
	struct rxrpc_call *call;

	_enter(",%lx", user_call_ID);
455
	call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID, notify_rx);
456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477
	_leave(" = %p", call);
	return call;
}
EXPORT_SYMBOL(rxrpc_kernel_accept_call);

/**
 * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
 * @sock: The socket on which the impending call is waiting
 *
 * Allow a kernel service to reject an incoming call with a BUSY message,
 * assuming the incoming call is still valid.
 */
int rxrpc_kernel_reject_call(struct socket *sock)
{
	int ret;

	_enter("");
	ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
	_leave(" = %d", ret);
	return ret;
}
EXPORT_SYMBOL(rxrpc_kernel_reject_call);