dccp.h

#ifndef _DCCP_H
#define _DCCP_H
/*
 *  net/dccp/dccp.h
 *
 *  An implementation of the DCCP protocol
 *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 *	This program is free software; you can redistribute it and/or modify it
 *	under the terms of the GNU General Public License version 2 as
 *	published by the Free Software Foundation.
 */

#include <linux/dccp.h>
#include <net/snmp.h>
#include <net/sock.h>
#include <net/tcp.h>

#define DCCP_DEBUG

#ifdef DCCP_DEBUG
extern int dccp_debug;

#define dccp_pr_debug(format, a...) \
	do { if (dccp_debug) \
		printk(KERN_DEBUG "%s: " format, __FUNCTION__ , ##a); \
	} while (0)
#define dccp_pr_debug_cat(format, a...) do { if (dccp_debug) printk(format, ##a); } while (0)
#else
#define dccp_pr_debug(format, a...)
#define dccp_pr_debug_cat(format, a...)
#endif

extern struct inet_hashinfo dccp_hashinfo;

extern atomic_t dccp_orphan_count;
extern int dccp_tw_count;
extern void dccp_tw_deschedule(struct inet_timewait_sock *tw);

extern void dccp_time_wait(struct sock *sk, int state, int timeo);

/* FIXME: Right size this */
#define DCCP_MAX_OPT_LEN 128

#define DCCP_MAX_PACKET_HDR 32

#define MAX_DCCP_HEADER  (DCCP_MAX_PACKET_HDR + DCCP_MAX_OPT_LEN + MAX_HEADER)

#define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
				     * state, about 60 seconds */

/* draft-ietf-dccp-spec-11.txt initial RTO value */
#define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))

/* Maximal interval between probes for local resources.  */
#define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))

#define DCCP_RTO_MAX ((unsigned)(120 * HZ)) /* FIXME: using TCP value */

extern struct proto dccp_v4_prot;

/* is seq1 < seq2 ? */
static inline const  int before48(const u64 seq1, const u64 seq2)
{
	return (const s64)((seq1 << 16) - (seq2 << 16)) < 0;
}

/* is seq1 > seq2 ? */
static inline const  int after48(const u64 seq1, const u64 seq2)
{
	return (const s64)((seq2 << 16) - (seq1 << 16)) < 0;
}

/* is seq2 <= seq1 <= seq3 ? */
static inline const int between48(const u64 seq1, const u64 seq2, const u64 seq3)
{
	return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
}

static inline u64 max48(const u64 seq1, const u64 seq2)
{
	return after48(seq1, seq2) ? seq1 : seq2;
}

enum {
	DCCP_MIB_NUM = 0,
	DCCP_MIB_ACTIVEOPENS,			/* ActiveOpens */
	DCCP_MIB_ESTABRESETS,			/* EstabResets */
	DCCP_MIB_CURRESTAB,			/* CurrEstab */
	DCCP_MIB_OUTSEGS,			/* OutSegs */ 
	DCCP_MIB_OUTRSTS,
	DCCP_MIB_ABORTONTIMEOUT,
	DCCP_MIB_TIMEOUTS,
	DCCP_MIB_ABORTFAILED,
	DCCP_MIB_PASSIVEOPENS,
	DCCP_MIB_ATTEMPTFAILS,
	DCCP_MIB_OUTDATAGRAMS,
	DCCP_MIB_INERRS,
	DCCP_MIB_OPTMANDATORYERROR,
	DCCP_MIB_INVALIDOPT,
	__DCCP_MIB_MAX
};

#define DCCP_MIB_MAX	__DCCP_MIB_MAX
struct dccp_mib {
	unsigned long	mibs[DCCP_MIB_MAX];
} __SNMP_MIB_ALIGN__;

DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
#define DCCP_INC_STATS(field)		SNMP_INC_STATS(dccp_statistics, field)
#define DCCP_INC_STATS_BH(field)	SNMP_INC_STATS_BH(dccp_statistics, field)
#define DCCP_INC_STATS_USER(field) 	SNMP_INC_STATS_USER(dccp_statistics, field)
#define DCCP_DEC_STATS(field)		SNMP_DEC_STATS(dccp_statistics, field)
#define DCCP_ADD_STATS_BH(field, val)	SNMP_ADD_STATS_BH(dccp_statistics, field, val)
#define DCCP_ADD_STATS_USER(field, val)	SNMP_ADD_STATS_USER(dccp_statistics, field, val)

extern int  dccp_transmit_skb(struct sock *sk, struct sk_buff *skb);
extern int  dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);

extern int dccp_send_response(struct sock *sk);
extern void dccp_send_ack(struct sock *sk);
extern void dccp_send_delayed_ack(struct sock *sk);
extern void dccp_send_sync(struct sock *sk, u64 seq);

extern int dccp_write_xmit(struct sock *sk, struct sk_buff *skb,
			   const int len);

extern void dccp_init_xmit_timers(struct sock *sk);
static inline void dccp_clear_xmit_timers(struct sock *sk)
{
	inet_csk_clear_xmit_timers(sk);
}

extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);

extern const char *dccp_packet_name(const int type);
extern const char *dccp_state_name(const int state);

static inline void dccp_set_state(struct sock *sk, const int state)
{
	const int oldstate = sk->sk_state;

	dccp_pr_debug("%s(%p) %-10.10s -> %s\n",
		      dccp_role(sk), sk,
		      dccp_state_name(oldstate), dccp_state_name(state));
	WARN_ON(state == oldstate);

	switch (state) {
	case DCCP_OPEN:
		if (oldstate != DCCP_OPEN)
			DCCP_INC_STATS(DCCP_MIB_CURRESTAB);
		break;

	case DCCP_CLOSED:
		if (oldstate == DCCP_CLOSING || oldstate == DCCP_OPEN)
			DCCP_INC_STATS(DCCP_MIB_ESTABRESETS);

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash != NULL &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
			inet_put_port(&dccp_hashinfo, sk);
		/* fall through */
	default:
		if (oldstate == DCCP_OPEN)
			DCCP_DEC_STATS(DCCP_MIB_CURRESTAB);
	}

	/* Change state AFTER socket is unhashed to avoid closed
	 * socket sitting in hash tables.
	 */
	sk->sk_state = state;
}

static inline void dccp_done(struct sock *sk)
{
	dccp_set_state(sk, DCCP_CLOSED);
	dccp_clear_xmit_timers(sk);

	sk->sk_shutdown = SHUTDOWN_MASK;

	if (!sock_flag(sk, SOCK_DEAD))
		sk->sk_state_change(sk);
	else
		inet_csk_destroy_sock(sk);
}

static inline void dccp_openreq_init(struct request_sock *req,
				     struct dccp_sock *dp,
				     struct sk_buff *skb)
{
	/*
	 * FIXME: fill in the other req fields from the DCCP options
	 * received
	 */
	inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
	inet_rsk(req)->acked	= 0;
	req->rcv_wnd = 0;
}

extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);

extern struct sock *dccp_create_openreq_child(struct sock *sk,
					      const struct request_sock *req,
					      const struct sk_buff *skb);

extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);

extern void dccp_v4_err(struct sk_buff *skb, u32);

extern int dccp_v4_rcv(struct sk_buff *skb);

extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
					      struct sk_buff *skb,
					      struct request_sock *req,
					      struct dst_entry *dst);
extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
				   struct request_sock *req,
				   struct request_sock **prev);

extern int dccp_child_process(struct sock *parent, struct sock *child,
			      struct sk_buff *skb);
extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
				  struct dccp_hdr *dh, unsigned len);
extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
				const struct dccp_hdr *dh, const unsigned len);

extern void		dccp_close(struct sock *sk, long timeout);
extern struct sk_buff	*dccp_make_response(struct sock *sk,
					    struct dst_entry *dst,
					    struct request_sock *req);

extern int	   dccp_connect(struct sock *sk);
extern int	   dccp_disconnect(struct sock *sk, int flags);
extern int	   dccp_getsockopt(struct sock *sk, int level, int optname,
				   char *optval, int *optlen);
extern int	   dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
extern int	   dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
				size_t size);
extern int	   dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
				struct msghdr *msg, size_t len, int nonblock,
				int flags, int *addr_len);
extern int	   dccp_setsockopt(struct sock *sk, int level, int optname,
				   char *optval, int optlen);
extern void	   dccp_shutdown(struct sock *sk, int how);

extern int	   dccp_v4_checksum(const struct sk_buff *skb,
				    const u32 saddr, const u32 daddr);

extern int	   dccp_v4_send_reset(struct sock *sk, enum dccp_reset_codes code);
extern void	   dccp_send_close(struct sock *sk);

struct dccp_skb_cb {
	__u8 dccpd_type;
	__u8 dccpd_reset_code;
	__u8 dccpd_service;
	__u8 dccpd_ccval;
	__u64 dccpd_seq;
	__u64 dccpd_ack_seq;
	int  dccpd_opt_len;
};

#define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))

static inline int dccp_non_data_packet(const struct sk_buff *skb)
{
	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;

	return type == DCCP_PKT_ACK	 ||
	       type == DCCP_PKT_CLOSE	 ||
	       type == DCCP_PKT_CLOSEREQ ||
	       type == DCCP_PKT_RESET	 ||
	       type == DCCP_PKT_SYNC	 ||
	       type == DCCP_PKT_SYNCACK;
}

static inline int dccp_packet_without_ack(const struct sk_buff *skb)
{
	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;

	return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
}

#define DCCP_MAX_SEQNO ((((u64)1) << 48) - 1)
#define DCCP_PKT_WITHOUT_ACK_SEQ (DCCP_MAX_SEQNO << 2)

static inline void dccp_set_seqno(u64 *seqno, u64 value)
{
	if (value > DCCP_MAX_SEQNO)
		value -= DCCP_MAX_SEQNO + 1;
	*seqno = value;
}

static inline u64 dccp_delta_seqno(u64 seqno1, u64 seqno2)
{
	return ((seqno2 << 16) - (seqno1 << 16)) >> 16;
}

static inline void dccp_inc_seqno(u64 *seqno)
{
	if (++*seqno > DCCP_MAX_SEQNO)
		*seqno = 0;
}

static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
{
	struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh + sizeof(*dh));

#if defined(__LITTLE_ENDIAN_BITFIELD)
	dh->dccph_seq	   = htonl((gss >> 32)) >> 8;
#elif defined(__BIG_ENDIAN_BITFIELD)
	dh->dccph_seq	   = htonl((gss >> 32));
#else
#error  "Adjust your <asm/byteorder.h> defines"
#endif
	dhx->dccph_seq_low = htonl(gss & 0xffffffff);
}

static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack, const u64 gsr)
{
#if defined(__LITTLE_ENDIAN_BITFIELD)
	dhack->dccph_ack_nr_high = htonl((gsr >> 32)) >> 8;
#elif defined(__BIG_ENDIAN_BITFIELD)
	dhack->dccph_ack_nr_high = htonl((gsr >> 32));
#else
#error  "Adjust your <asm/byteorder.h> defines"
#endif
	dhack->dccph_ack_nr_low  = htonl(gsr & 0xffffffff);
}

static inline void dccp_update_gsr(struct sock *sk, u64 seq)
{
	struct dccp_sock *dp = dccp_sk(sk);
	u64 tmp_gsr;

	dccp_set_seqno(&tmp_gsr, dp->dccps_gsr + 1 - (dp->dccps_options.dccpo_sequence_window / 4));
	dp->dccps_gsr = seq;
	dccp_set_seqno(&dp->dccps_swl, max48(tmp_gsr, dp->dccps_isr));
	dccp_set_seqno(&dp->dccps_swh,
		       dp->dccps_gsr + (3 * dp->dccps_options.dccpo_sequence_window) / 4);
}

static inline void dccp_update_gss(struct sock *sk, u64 seq)
{
	struct dccp_sock *dp = dccp_sk(sk);
	u64 tmp_gss;

	dccp_set_seqno(&tmp_gss, dp->dccps_gss - dp->dccps_options.dccpo_sequence_window + 1);
	dp->dccps_awl = max48(tmp_gss, dp->dccps_iss);
	dp->dccps_awh = dp->dccps_gss = seq;
}

extern void dccp_insert_options(struct sock *sk, struct sk_buff *skb);
extern void dccp_insert_option_elapsed_time(struct sock *sk,
					    struct sk_buff *skb,
					    u32 elapsed_time);
extern void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
			       unsigned char option,
			       const void *value, unsigned char len);

extern struct socket *dccp_ctl_socket;

#define DCCP_ACKPKTS_STATE_RECEIVED	0
#define DCCP_ACKPKTS_STATE_ECN_MARKED	(1 << 6)
#define DCCP_ACKPKTS_STATE_NOT_RECEIVED	(3 << 6)

#define DCCP_ACKPKTS_STATE_MASK		0xC0 /* 11000000 */
#define DCCP_ACKPKTS_LEN_MASK		0x3F /* 00111111 */

/** struct dccp_ackpkts - acknowledgeable packets
 *
 * This data structure is the one defined in the DCCP draft
 * Appendix A.
 *
 * @dccpap_buf_head - circular buffer head
 * @dccpap_buf_tail - circular buffer tail
 * @dccpap_buf_ackno - ack # of the most recent packet acknoldgeable in the buffer (i.e. %dccpap_buf_head)
 * @dccpap_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked by the buffer with State 0
 *
 * Additionally, the HC-Receiver must keep some information about the
 * Ack Vectors it has recently sent. For each packet sent carrying an
 * Ack Vector, it remembers four variables:
 *
 * @dccpap_ack_seqno - the Sequence Number used for the packet (HC-Receiver seqno)
 * @dccpap_ack_ptr - the value of buf_head at the time of acknowledgement.
 * @dccpap_ack_ackno - the Acknowledgement Number used for the packet (HC-Sender seqno)
 * @dccpap_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
 *
 * @dccpap_buf_len - circular buffer length
 * @dccpap_buf - circular buffer of acknowledgeable packets
 */
struct dccp_ackpkts {
	unsigned int		dccpap_buf_head;
	unsigned int		dccpap_buf_tail;
	u64			dccpap_buf_ackno;
	u64			dccpap_ack_seqno;
	u64			dccpap_ack_ackno;
	unsigned int		dccpap_ack_ptr;
	unsigned int		dccpap_buf_vector_len;
	unsigned int		dccpap_ack_vector_len;
	unsigned int		dccpap_buf_len;
	unsigned long           dccpap_time;
	u8			dccpap_buf_nonce;
	u8			dccpap_ack_nonce;
	u8			dccpap_buf[0];
};

extern struct dccp_ackpkts *dccp_ackpkts_alloc(unsigned int len, int priority);
extern void dccp_ackpkts_free(struct dccp_ackpkts *ap);
extern int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state);
extern void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap,
					 struct sock *sk, u64 ackno);

#ifdef DCCP_DEBUG
extern void dccp_ackvector_print(const u64 ackno,
				 const unsigned char *vector, int len);
extern void dccp_ackpkts_print(const struct dccp_ackpkts *ap);
#else
static inline void dccp_ackvector_print(const u64 ackno,
					const unsigned char *vector,
					int len) { }
static inline void dccp_ackpkts_print(const struct dccp_ackpkts *ap) { }
#endif

#endif /* _DCCP_H */