2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * Definitions for the TCP module.
8 * Version: @(#)tcp.h 1.0.5 05/23/93
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
22 #define FASTRETRANS_DEBUG 1
24 #include <linux/list.h>
25 #include <linux/tcp.h>
26 #include <linux/slab.h>
27 #include <linux/cache.h>
28 #include <linux/percpu.h>
29 #include <linux/skbuff.h>
30 #include <linux/dmaengine.h>
31 #include <linux/crypto.h>
32 #include <linux/cryptohash.h>
34 #include <net/inet_connection_sock.h>
35 #include <net/inet_timewait_sock.h>
36 #include <net/inet_hashtables.h>
37 #include <net/checksum.h>
38 #include <net/request_sock.h>
42 #include <net/tcp_states.h>
43 #include <net/inet_ecn.h>
46 #include <linux/seq_file.h>
48 extern struct inet_hashinfo tcp_hashinfo;
50 extern struct percpu_counter tcp_orphan_count;
51 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
53 #define MAX_TCP_HEADER (128 + MAX_HEADER)
54 #define MAX_TCP_OPTION_SPACE 40
57 * Never offer a window over 32767 without using window scaling. Some
58 * poor stacks do signed 16bit maths!
60 #define MAX_TCP_WINDOW 32767U
62 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
63 #define TCP_MIN_MSS 88U
65 /* The least MTU to use for probing */
66 #define TCP_BASE_MSS 512
68 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
69 #define TCP_FASTRETRANS_THRESH 3
71 /* Maximal reordering. */
72 #define TCP_MAX_REORDERING 127
74 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
75 #define TCP_MAX_QUICKACKS 16U
78 #define TCP_URG_VALID 0x0100
79 #define TCP_URG_NOTYET 0x0200
80 #define TCP_URG_READ 0x0400
82 #define TCP_RETR1 3 /*
83 * This is how many retries it does before it
84 * tries to figure out if the gateway is
85 * down. Minimal RFC value is 3; it corresponds
86 * to ~3sec-8min depending on RTO.
89 #define TCP_RETR2 15 /*
90 * This should take at least
91 * 90 minutes to time out.
92 * RFC1122 says that the limit is 100 sec.
93 * 15 is ~13-30min depending on RTO.
96 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
97 * connection: ~180sec is RFC minimum */
99 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
100 * connection: ~180sec is RFC minimum */
103 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
104 * socket. 7 is ~50sec-16min.
108 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
109 * state, about 60 seconds */
110 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
111 /* BSD style FIN_WAIT2 deadlock breaker.
112 * It used to be 3min, new value is 60sec,
113 * to combine FIN-WAIT-2 timeout with
117 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
119 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
120 #define TCP_ATO_MIN ((unsigned)(HZ/25))
122 #define TCP_DELACK_MIN 4U
123 #define TCP_ATO_MIN 4U
125 #define TCP_RTO_MAX ((unsigned)(120*HZ))
126 #define TCP_RTO_MIN ((unsigned)(HZ/5))
127 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
129 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
130 * for local resources.
133 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
134 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
135 #define TCP_KEEPALIVE_INTVL (75*HZ)
137 #define MAX_TCP_KEEPIDLE 32767
138 #define MAX_TCP_KEEPINTVL 32767
139 #define MAX_TCP_KEEPCNT 127
140 #define MAX_TCP_SYNCNT 127
142 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
144 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
145 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
146 * after this time. It should be equal
147 * (or greater than) TCP_TIMEWAIT_LEN
148 * to provide reliability equal to one
149 * provided by timewait state.
151 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
152 * timestamps. It must be less than
153 * minimal timewait lifetime.
159 #define TCPOPT_NOP 1 /* Padding */
160 #define TCPOPT_EOL 0 /* End of options */
161 #define TCPOPT_MSS 2 /* Segment size negotiating */
162 #define TCPOPT_WINDOW 3 /* Window scaling */
163 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
164 #define TCPOPT_SACK 5 /* SACK Block */
165 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
166 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
172 #define TCPOLEN_MSS 4
173 #define TCPOLEN_WINDOW 3
174 #define TCPOLEN_SACK_PERM 2
175 #define TCPOLEN_TIMESTAMP 10
176 #define TCPOLEN_MD5SIG 18
178 /* But this is what stacks really send out. */
179 #define TCPOLEN_TSTAMP_ALIGNED 12
180 #define TCPOLEN_WSCALE_ALIGNED 4
181 #define TCPOLEN_SACKPERM_ALIGNED 4
182 #define TCPOLEN_SACK_BASE 2
183 #define TCPOLEN_SACK_BASE_ALIGNED 4
184 #define TCPOLEN_SACK_PERBLOCK 8
185 #define TCPOLEN_MD5SIG_ALIGNED 20
186 #define TCPOLEN_MSS_ALIGNED 4
188 /* Flags in tp->nonagle */
189 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
190 #define TCP_NAGLE_CORK 2 /* Socket is corked */
191 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
193 extern struct inet_timewait_death_row tcp_death_row;
195 /* sysctl variables for tcp */
196 extern int sysctl_tcp_timestamps;
197 extern int sysctl_tcp_window_scaling;
198 extern int sysctl_tcp_sack;
199 extern int sysctl_tcp_fin_timeout;
200 extern int sysctl_tcp_keepalive_time;
201 extern int sysctl_tcp_keepalive_probes;
202 extern int sysctl_tcp_keepalive_intvl;
203 extern int sysctl_tcp_syn_retries;
204 extern int sysctl_tcp_synack_retries;
205 extern int sysctl_tcp_retries1;
206 extern int sysctl_tcp_retries2;
207 extern int sysctl_tcp_orphan_retries;
208 extern int sysctl_tcp_syncookies;
209 extern int sysctl_tcp_retrans_collapse;
210 extern int sysctl_tcp_stdurg;
211 extern int sysctl_tcp_rfc1337;
212 extern int sysctl_tcp_abort_on_overflow;
213 extern int sysctl_tcp_max_orphans;
214 extern int sysctl_tcp_fack;
215 extern int sysctl_tcp_reordering;
216 extern int sysctl_tcp_ecn;
217 extern int sysctl_tcp_dsack;
218 extern int sysctl_tcp_mem[3];
219 extern int sysctl_tcp_wmem[3];
220 extern int sysctl_tcp_rmem[3];
221 extern int sysctl_tcp_app_win;
222 extern int sysctl_tcp_adv_win_scale;
223 extern int sysctl_tcp_tw_reuse;
224 extern int sysctl_tcp_frto;
225 extern int sysctl_tcp_frto_response;
226 extern int sysctl_tcp_low_latency;
227 extern int sysctl_tcp_dma_copybreak;
228 extern int sysctl_tcp_nometrics_save;
229 extern int sysctl_tcp_moderate_rcvbuf;
230 extern int sysctl_tcp_tso_win_divisor;
231 extern int sysctl_tcp_abc;
232 extern int sysctl_tcp_mtu_probing;
233 extern int sysctl_tcp_base_mss;
234 extern int sysctl_tcp_workaround_signed_windows;
235 extern int sysctl_tcp_slow_start_after_idle;
236 extern int sysctl_tcp_max_ssthresh;
238 extern atomic_t tcp_memory_allocated;
239 extern struct percpu_counter tcp_sockets_allocated;
240 extern int tcp_memory_pressure;
243 * The next routines deal with comparing 32 bit unsigned ints
244 * and worry about wraparound (automatic with unsigned arithmetic).
247 static inline int before(__u32 seq1, __u32 seq2)
249 return (__s32)(seq1-seq2) < 0;
251 #define after(seq2, seq1) before(seq1, seq2)
253 /* is s2<=s1<=s3 ? */
254 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
256 return seq3 - seq2 >= seq1 - seq2;
259 static inline int tcp_too_many_orphans(struct sock *sk, int num)
261 return (num > sysctl_tcp_max_orphans) ||
262 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
263 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
266 /* syncookies: remember time of last synqueue overflow */
267 static inline void tcp_synq_overflow(struct sock *sk)
269 tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies;
272 /* syncookies: no recent synqueue overflow on this listening socket? */
273 static inline int tcp_synq_no_recent_overflow(const struct sock *sk)
275 unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp;
276 return time_after(jiffies, last_overflow + TCP_TIMEOUT_INIT);
279 extern struct proto tcp_prot;
281 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
282 #define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field)
283 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
284 #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
286 extern void tcp_v4_err(struct sk_buff *skb, u32);
288 extern void tcp_shutdown (struct sock *sk, int how);
290 extern int tcp_v4_rcv(struct sk_buff *skb);
292 extern int tcp_v4_remember_stamp(struct sock *sk);
294 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
296 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
297 struct msghdr *msg, size_t size);
298 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
300 extern int tcp_ioctl(struct sock *sk,
304 extern int tcp_rcv_state_process(struct sock *sk,
309 extern int tcp_rcv_established(struct sock *sk,
314 extern void tcp_rcv_space_adjust(struct sock *sk);
316 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
318 extern int tcp_twsk_unique(struct sock *sk,
319 struct sock *sktw, void *twp);
321 extern void tcp_twsk_destructor(struct sock *sk);
323 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
324 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
326 static inline void tcp_dec_quickack_mode(struct sock *sk,
327 const unsigned int pkts)
329 struct inet_connection_sock *icsk = inet_csk(sk);
331 if (icsk->icsk_ack.quick) {
332 if (pkts >= icsk->icsk_ack.quick) {
333 icsk->icsk_ack.quick = 0;
334 /* Leaving quickack mode we deflate ATO. */
335 icsk->icsk_ack.ato = TCP_ATO_MIN;
337 icsk->icsk_ack.quick -= pkts;
341 extern void tcp_enter_quickack_mode(struct sock *sk);
343 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
345 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
349 #define TCP_ECN_QUEUE_CWR 2
350 #define TCP_ECN_DEMAND_CWR 4
352 static __inline__ void
353 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
355 if (sysctl_tcp_ecn && th->ece && th->cwr)
356 inet_rsk(req)->ecn_ok = 1;
367 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
369 const struct tcphdr *th);
371 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
372 struct request_sock *req,
373 struct request_sock **prev);
374 extern int tcp_child_process(struct sock *parent,
376 struct sk_buff *skb);
377 extern int tcp_use_frto(struct sock *sk);
378 extern void tcp_enter_frto(struct sock *sk);
379 extern void tcp_enter_loss(struct sock *sk, int how);
380 extern void tcp_clear_retrans(struct tcp_sock *tp);
381 extern void tcp_update_metrics(struct sock *sk);
383 extern void tcp_close(struct sock *sk,
385 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
387 extern int tcp_getsockopt(struct sock *sk, int level,
391 extern int tcp_setsockopt(struct sock *sk, int level,
392 int optname, char __user *optval,
393 unsigned int optlen);
394 extern int compat_tcp_getsockopt(struct sock *sk,
395 int level, int optname,
396 char __user *optval, int __user *optlen);
397 extern int compat_tcp_setsockopt(struct sock *sk,
398 int level, int optname,
399 char __user *optval, unsigned int optlen);
400 extern void tcp_set_keepalive(struct sock *sk, int val);
401 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
403 size_t len, int nonblock,
404 int flags, int *addr_len);
406 extern void tcp_parse_options(struct sk_buff *skb,
407 struct tcp_options_received *opt_rx,
409 struct dst_entry *dst);
411 extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
414 * TCP v4 functions exported for the inet6 API
417 extern void tcp_v4_send_check(struct sock *sk, int len,
418 struct sk_buff *skb);
420 extern int tcp_v4_conn_request(struct sock *sk,
421 struct sk_buff *skb);
423 extern struct sock * tcp_create_openreq_child(struct sock *sk,
424 struct request_sock *req,
425 struct sk_buff *skb);
427 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
429 struct request_sock *req,
430 struct dst_entry *dst);
432 extern int tcp_v4_do_rcv(struct sock *sk,
433 struct sk_buff *skb);
435 extern int tcp_v4_connect(struct sock *sk,
436 struct sockaddr *uaddr,
439 extern int tcp_connect(struct sock *sk);
441 extern struct sk_buff * tcp_make_synack(struct sock *sk,
442 struct dst_entry *dst,
443 struct request_sock *req,
444 struct request_values *rvp);
446 extern int tcp_disconnect(struct sock *sk, int flags);
449 /* From syncookies.c */
450 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
451 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
452 struct ip_options *opt);
453 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
456 extern __u32 cookie_init_timestamp(struct request_sock *req);
457 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
459 /* From net/ipv6/syncookies.c */
460 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
461 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
466 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
468 extern int tcp_may_send_now(struct sock *sk);
469 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
470 extern void tcp_retransmit_timer(struct sock *sk);
471 extern void tcp_xmit_retransmit_queue(struct sock *);
472 extern void tcp_simple_retransmit(struct sock *);
473 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
474 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
476 extern void tcp_send_probe0(struct sock *);
477 extern void tcp_send_partial(struct sock *);
478 extern int tcp_write_wakeup(struct sock *);
479 extern void tcp_send_fin(struct sock *sk);
480 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
481 extern int tcp_send_synack(struct sock *);
482 extern void tcp_push_one(struct sock *, unsigned int mss_now);
483 extern void tcp_send_ack(struct sock *sk);
484 extern void tcp_send_delayed_ack(struct sock *sk);
487 extern void tcp_cwnd_application_limited(struct sock *sk);
490 extern void tcp_init_xmit_timers(struct sock *);
491 static inline void tcp_clear_xmit_timers(struct sock *sk)
493 inet_csk_clear_xmit_timers(sk);
496 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
497 extern unsigned int tcp_current_mss(struct sock *sk);
499 /* Bound MSS / TSO packet size with the half of the window */
500 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
502 if (tp->max_window && pktsize > (tp->max_window >> 1))
503 return max(tp->max_window >> 1, 68U - tp->tcp_header_len);
509 extern void tcp_get_info(struct sock *, struct tcp_info *);
511 /* Read 'sendfile()'-style from a TCP socket */
512 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
513 unsigned int, size_t);
514 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
515 sk_read_actor_t recv_actor);
517 extern void tcp_initialize_rcv_mss(struct sock *sk);
519 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
520 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
521 extern void tcp_mtup_init(struct sock *sk);
523 static inline void tcp_bound_rto(const struct sock *sk)
525 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX)
526 inet_csk(sk)->icsk_rto = TCP_RTO_MAX;
529 static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
531 return (tp->srtt >> 3) + tp->rttvar;
534 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
536 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
537 ntohl(TCP_FLAG_ACK) |
541 static inline void tcp_fast_path_on(struct tcp_sock *tp)
543 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
546 static inline void tcp_fast_path_check(struct sock *sk)
548 struct tcp_sock *tp = tcp_sk(sk);
550 if (skb_queue_empty(&tp->out_of_order_queue) &&
552 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
554 tcp_fast_path_on(tp);
557 /* Compute the actual rto_min value */
558 static inline u32 tcp_rto_min(struct sock *sk)
560 struct dst_entry *dst = __sk_dst_get(sk);
561 u32 rto_min = TCP_RTO_MIN;
563 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))
564 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN);
568 /* Compute the actual receive window we are currently advertising.
569 * Rcv_nxt can be after the window if our peer push more data
570 * than the offered window.
572 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
574 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
581 /* Choose a new window, without checks for shrinking, and without
582 * scaling applied to the result. The caller does these things
583 * if necessary. This is a "raw" window selection.
585 extern u32 __tcp_select_window(struct sock *sk);
587 /* TCP timestamps are only 32-bits, this causes a slight
588 * complication on 64-bit systems since we store a snapshot
589 * of jiffies in the buffer control blocks below. We decided
590 * to use only the low 32-bits of jiffies and hide the ugly
591 * casts with the following macro.
593 #define tcp_time_stamp ((__u32)(jiffies))
595 /* This is what the send packet queuing engine uses to pass
596 * TCP per-packet control information to the transmission
597 * code. We also store the host-order sequence numbers in
598 * here too. This is 36 bytes on 32-bit architectures,
599 * 40 bytes on 64-bit machines, if this grows please adjust
600 * skbuff.h:skbuff->cb[xxx] size appropriately.
604 struct inet_skb_parm h4;
605 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
606 struct inet6_skb_parm h6;
608 } header; /* For incoming frames */
609 __u32 seq; /* Starting sequence number */
610 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
611 __u32 when; /* used to compute rtt's */
612 __u8 flags; /* TCP header flags. */
614 /* NOTE: These must match up to the flags byte in a
617 #define TCPCB_FLAG_FIN 0x01
618 #define TCPCB_FLAG_SYN 0x02
619 #define TCPCB_FLAG_RST 0x04
620 #define TCPCB_FLAG_PSH 0x08
621 #define TCPCB_FLAG_ACK 0x10
622 #define TCPCB_FLAG_URG 0x20
623 #define TCPCB_FLAG_ECE 0x40
624 #define TCPCB_FLAG_CWR 0x80
626 __u8 sacked; /* State flags for SACK/FACK. */
627 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
628 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
629 #define TCPCB_LOST 0x04 /* SKB is lost */
630 #define TCPCB_TAGBITS 0x07 /* All tag bits */
632 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
633 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
635 __u32 ack_seq; /* Sequence number ACK'd */
638 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
640 /* Due to TSO, an SKB can be composed of multiple actual
641 * packets. To keep these tracked properly, we use this.
643 static inline int tcp_skb_pcount(const struct sk_buff *skb)
645 return skb_shinfo(skb)->gso_segs;
648 /* This is valid iff tcp_skb_pcount() > 1. */
649 static inline int tcp_skb_mss(const struct sk_buff *skb)
651 return skb_shinfo(skb)->gso_size;
654 /* Events passed to congestion control interface */
656 CA_EVENT_TX_START, /* first transmit when no packets in flight */
657 CA_EVENT_CWND_RESTART, /* congestion window restart */
658 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
659 CA_EVENT_FRTO, /* fast recovery timeout */
660 CA_EVENT_LOSS, /* loss timeout */
661 CA_EVENT_FAST_ACK, /* in sequence ack */
662 CA_EVENT_SLOW_ACK, /* other ack */
666 * Interface for adding new TCP congestion control handlers
668 #define TCP_CA_NAME_MAX 16
669 #define TCP_CA_MAX 128
670 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
672 #define TCP_CONG_NON_RESTRICTED 0x1
673 #define TCP_CONG_RTT_STAMP 0x2
675 struct tcp_congestion_ops {
676 struct list_head list;
679 /* initialize private data (optional) */
680 void (*init)(struct sock *sk);
681 /* cleanup private data (optional) */
682 void (*release)(struct sock *sk);
684 /* return slow start threshold (required) */
685 u32 (*ssthresh)(struct sock *sk);
686 /* lower bound for congestion window (optional) */
687 u32 (*min_cwnd)(const struct sock *sk);
688 /* do new cwnd calculation (required) */
689 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
690 /* call before changing ca_state (optional) */
691 void (*set_state)(struct sock *sk, u8 new_state);
692 /* call when cwnd event occurs (optional) */
693 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
694 /* new value of cwnd after loss (optional) */
695 u32 (*undo_cwnd)(struct sock *sk);
696 /* hook for packet ack accounting (optional) */
697 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
698 /* get info for inet_diag (optional) */
699 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
701 char name[TCP_CA_NAME_MAX];
702 struct module *owner;
705 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
706 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
708 extern void tcp_init_congestion_control(struct sock *sk);
709 extern void tcp_cleanup_congestion_control(struct sock *sk);
710 extern int tcp_set_default_congestion_control(const char *name);
711 extern void tcp_get_default_congestion_control(char *name);
712 extern void tcp_get_available_congestion_control(char *buf, size_t len);
713 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
714 extern int tcp_set_allowed_congestion_control(char *allowed);
715 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
716 extern void tcp_slow_start(struct tcp_sock *tp);
717 extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w);
719 extern struct tcp_congestion_ops tcp_init_congestion_ops;
720 extern u32 tcp_reno_ssthresh(struct sock *sk);
721 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
722 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
723 extern struct tcp_congestion_ops tcp_reno;
725 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
727 struct inet_connection_sock *icsk = inet_csk(sk);
729 if (icsk->icsk_ca_ops->set_state)
730 icsk->icsk_ca_ops->set_state(sk, ca_state);
731 icsk->icsk_ca_state = ca_state;
734 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
736 const struct inet_connection_sock *icsk = inet_csk(sk);
738 if (icsk->icsk_ca_ops->cwnd_event)
739 icsk->icsk_ca_ops->cwnd_event(sk, event);
742 /* These functions determine how the current flow behaves in respect of SACK
743 * handling. SACK is negotiated with the peer, and therefore it can vary
744 * between different flows.
746 * tcp_is_sack - SACK enabled
747 * tcp_is_reno - No SACK
748 * tcp_is_fack - FACK enabled, implies SACK enabled
750 static inline int tcp_is_sack(const struct tcp_sock *tp)
752 return tp->rx_opt.sack_ok;
755 static inline int tcp_is_reno(const struct tcp_sock *tp)
757 return !tcp_is_sack(tp);
760 static inline int tcp_is_fack(const struct tcp_sock *tp)
762 return tp->rx_opt.sack_ok & 2;
765 static inline void tcp_enable_fack(struct tcp_sock *tp)
767 tp->rx_opt.sack_ok |= 2;
770 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
772 return tp->sacked_out + tp->lost_out;
775 /* This determines how many packets are "in the network" to the best
776 * of our knowledge. In many cases it is conservative, but where
777 * detailed information is available from the receiver (via SACK
778 * blocks etc.) we can make more aggressive calculations.
780 * Use this for decisions involving congestion control, use just
781 * tp->packets_out to determine if the send queue is empty or not.
783 * Read this equation as:
785 * "Packets sent once on transmission queue" MINUS
786 * "Packets left network, but not honestly ACKed yet" PLUS
787 * "Packets fast retransmitted"
789 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
791 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
794 #define TCP_INFINITE_SSTHRESH 0x7fffffff
796 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp)
798 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH;
801 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
802 * The exception is rate halving phase, when cwnd is decreasing towards
805 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
807 const struct tcp_sock *tp = tcp_sk(sk);
808 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
809 return tp->snd_ssthresh;
811 return max(tp->snd_ssthresh,
812 ((tp->snd_cwnd >> 1) +
813 (tp->snd_cwnd >> 2)));
816 /* Use define here intentionally to get WARN_ON location shown at the caller */
817 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
819 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
820 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
822 /* Slow start with delack produces 3 packets of burst, so that
823 * it is safe "de facto". This will be the default - same as
824 * the default reordering threshold - but if reordering increases,
825 * we must be able to allow cwnd to burst at least this much in order
826 * to not pull it back when holes are filled.
828 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
830 return tp->reordering;
833 /* Returns end sequence number of the receiver's advertised window */
834 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
836 return tp->snd_una + tp->snd_wnd;
838 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
840 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
841 const struct sk_buff *skb)
844 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
847 static inline void tcp_check_probe_timer(struct sock *sk)
849 struct tcp_sock *tp = tcp_sk(sk);
850 const struct inet_connection_sock *icsk = inet_csk(sk);
852 if (!tp->packets_out && !icsk->icsk_pending)
853 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
854 icsk->icsk_rto, TCP_RTO_MAX);
857 static inline void tcp_push_pending_frames(struct sock *sk)
859 struct tcp_sock *tp = tcp_sk(sk);
861 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle);
864 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)
869 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq)
875 * Calculate(/check) TCP checksum
877 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
878 __be32 daddr, __wsum base)
880 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
883 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
885 return __skb_checksum_complete(skb);
888 static inline int tcp_checksum_complete(struct sk_buff *skb)
890 return !skb_csum_unnecessary(skb) &&
891 __tcp_checksum_complete(skb);
894 /* Prequeue for VJ style copy to user, combined with checksumming. */
896 static inline void tcp_prequeue_init(struct tcp_sock *tp)
898 tp->ucopy.task = NULL;
900 tp->ucopy.memory = 0;
901 skb_queue_head_init(&tp->ucopy.prequeue);
902 #ifdef CONFIG_NET_DMA
903 tp->ucopy.dma_chan = NULL;
904 tp->ucopy.wakeup = 0;
905 tp->ucopy.pinned_list = NULL;
906 tp->ucopy.dma_cookie = 0;
910 /* Packet is added to VJ-style prequeue for processing in process
911 * context, if a reader task is waiting. Apparently, this exciting
912 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
913 * failed somewhere. Latency? Burstiness? Well, at least now we will
914 * see, why it failed. 8)8) --ANK
916 * NOTE: is this not too big to inline?
918 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
920 struct tcp_sock *tp = tcp_sk(sk);
922 if (sysctl_tcp_low_latency || !tp->ucopy.task)
925 __skb_queue_tail(&tp->ucopy.prequeue, skb);
926 tp->ucopy.memory += skb->truesize;
927 if (tp->ucopy.memory > sk->sk_rcvbuf) {
928 struct sk_buff *skb1;
930 BUG_ON(sock_owned_by_user(sk));
932 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
933 sk_backlog_rcv(sk, skb1);
934 NET_INC_STATS_BH(sock_net(sk),
935 LINUX_MIB_TCPPREQUEUEDROPPED);
938 tp->ucopy.memory = 0;
939 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
940 wake_up_interruptible_poll(sk->sk_sleep,
941 POLLIN | POLLRDNORM | POLLRDBAND);
942 if (!inet_csk_ack_scheduled(sk))
943 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
944 (3 * tcp_rto_min(sk)) / 4,
954 static const char *statename[]={
955 "Unused","Established","Syn Sent","Syn Recv",
956 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
957 "Close Wait","Last ACK","Listen","Closing"
960 extern void tcp_set_state(struct sock *sk, int state);
962 extern void tcp_done(struct sock *sk);
964 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
967 rx_opt->num_sacks = 0;
970 /* Determine a window scaling and initial window to offer. */
971 extern void tcp_select_initial_window(int __space, __u32 mss,
972 __u32 *rcv_wnd, __u32 *window_clamp,
973 int wscale_ok, __u8 *rcv_wscale);
975 static inline int tcp_win_from_space(int space)
977 return sysctl_tcp_adv_win_scale<=0 ?
978 (space>>(-sysctl_tcp_adv_win_scale)) :
979 space - (space>>sysctl_tcp_adv_win_scale);
982 /* Note: caller must be prepared to deal with negative returns */
983 static inline int tcp_space(const struct sock *sk)
985 return tcp_win_from_space(sk->sk_rcvbuf -
986 atomic_read(&sk->sk_rmem_alloc));
989 static inline int tcp_full_space(const struct sock *sk)
991 return tcp_win_from_space(sk->sk_rcvbuf);
994 static inline void tcp_openreq_init(struct request_sock *req,
995 struct tcp_options_received *rx_opt,
998 struct inet_request_sock *ireq = inet_rsk(req);
1000 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
1002 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
1003 req->mss = rx_opt->mss_clamp;
1004 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
1005 ireq->tstamp_ok = rx_opt->tstamp_ok;
1006 ireq->sack_ok = rx_opt->sack_ok;
1007 ireq->snd_wscale = rx_opt->snd_wscale;
1008 ireq->wscale_ok = rx_opt->wscale_ok;
1011 ireq->rmt_port = tcp_hdr(skb)->source;
1012 ireq->loc_port = tcp_hdr(skb)->dest;
1015 extern void tcp_enter_memory_pressure(struct sock *sk);
1017 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1019 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
1022 static inline int keepalive_time_when(const struct tcp_sock *tp)
1024 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
1027 static inline int keepalive_probes(const struct tcp_sock *tp)
1029 return tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
1032 static inline int tcp_fin_time(const struct sock *sk)
1034 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1035 const int rto = inet_csk(sk)->icsk_rto;
1037 if (fin_timeout < (rto << 2) - (rto >> 1))
1038 fin_timeout = (rto << 2) - (rto >> 1);
1043 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt,
1046 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
1048 if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))
1054 static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt,
1057 if (tcp_paws_check(rx_opt, 0))
1060 /* RST segments are not recommended to carry timestamp,
1061 and, if they do, it is recommended to ignore PAWS because
1062 "their cleanup function should take precedence over timestamps."
1063 Certainly, it is mistake. It is necessary to understand the reasons
1064 of this constraint to relax it: if peer reboots, clock may go
1065 out-of-sync and half-open connections will not be reset.
1066 Actually, the problem would be not existing if all
1067 the implementations followed draft about maintaining clock
1068 via reboots. Linux-2.2 DOES NOT!
1070 However, we can relax time bounds for RST segments to MSL.
1072 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1077 #define TCP_CHECK_TIMER(sk) do { } while (0)
1079 static inline void tcp_mib_init(struct net *net)
1082 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
1083 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1084 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1085 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
1089 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1091 tp->lost_skb_hint = NULL;
1092 tp->scoreboard_skb_hint = NULL;
1095 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1097 tcp_clear_retrans_hints_partial(tp);
1098 tp->retransmit_skb_hint = NULL;
1104 /* - key database */
1105 struct tcp_md5sig_key {
1110 struct tcp4_md5sig_key {
1111 struct tcp_md5sig_key base;
1115 struct tcp6_md5sig_key {
1116 struct tcp_md5sig_key base;
1118 u32 scope_id; /* XXX */
1120 struct in6_addr addr;
1124 struct tcp_md5sig_info {
1125 struct tcp4_md5sig_key *keys4;
1126 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1127 struct tcp6_md5sig_key *keys6;
1135 /* - pseudo header */
1136 struct tcp4_pseudohdr {
1144 struct tcp6_pseudohdr {
1145 struct in6_addr saddr;
1146 struct in6_addr daddr;
1148 __be32 protocol; /* including padding */
1151 union tcp_md5sum_block {
1152 struct tcp4_pseudohdr ip4;
1153 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1154 struct tcp6_pseudohdr ip6;
1158 /* - pool: digest algorithm, hash description and scratch buffer */
1159 struct tcp_md5sig_pool {
1160 struct hash_desc md5_desc;
1161 union tcp_md5sum_block md5_blk;
1164 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1167 extern int tcp_v4_md5_hash_skb(char *md5_hash,
1168 struct tcp_md5sig_key *key,
1170 struct request_sock *req,
1171 struct sk_buff *skb);
1173 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1174 struct sock *addr_sk);
1176 extern int tcp_v4_md5_do_add(struct sock *sk,
1181 extern int tcp_v4_md5_do_del(struct sock *sk,
1184 #ifdef CONFIG_TCP_MD5SIG
1185 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1186 &(struct tcp_md5sig_key) { \
1187 .key = (twsk)->tw_md5_key, \
1188 .keylen = (twsk)->tw_md5_keylen, \
1191 #define tcp_twsk_md5_key(twsk) NULL
1194 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(struct sock *);
1195 extern void tcp_free_md5sig_pool(void);
1197 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1198 extern void __tcp_put_md5sig_pool(void);
1199 extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *);
1200 extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *,
1201 unsigned header_len);
1202 extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1203 struct tcp_md5sig_key *key);
1206 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1208 int cpu = get_cpu();
1209 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1215 static inline void tcp_put_md5sig_pool(void)
1217 __tcp_put_md5sig_pool();
1221 /* write queue abstraction */
1222 static inline void tcp_write_queue_purge(struct sock *sk)
1224 struct sk_buff *skb;
1226 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1227 sk_wmem_free_skb(sk, skb);
1231 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1233 return skb_peek(&sk->sk_write_queue);
1236 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1238 return skb_peek_tail(&sk->sk_write_queue);
1241 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1243 return skb_queue_next(&sk->sk_write_queue, skb);
1246 static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_buff *skb)
1248 return skb_queue_prev(&sk->sk_write_queue, skb);
1251 #define tcp_for_write_queue(skb, sk) \
1252 skb_queue_walk(&(sk)->sk_write_queue, skb)
1254 #define tcp_for_write_queue_from(skb, sk) \
1255 skb_queue_walk_from(&(sk)->sk_write_queue, skb)
1257 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1258 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
1260 /* This function calculates a "timeout" which is equivalent to the timeout of a
1261 * TCP connection after "boundary" unsucessful, exponentially backed-off
1262 * retransmissions with an initial RTO of TCP_RTO_MIN.
1264 static inline bool retransmits_timed_out(const struct sock *sk,
1265 unsigned int boundary)
1267 unsigned int timeout, linear_backoff_thresh;
1269 if (!inet_csk(sk)->icsk_retransmits)
1272 linear_backoff_thresh = ilog2(TCP_RTO_MAX/TCP_RTO_MIN);
1274 if (boundary <= linear_backoff_thresh)
1275 timeout = ((2 << boundary) - 1) * TCP_RTO_MIN;
1277 timeout = ((2 << linear_backoff_thresh) - 1) * TCP_RTO_MIN +
1278 (boundary - linear_backoff_thresh) * TCP_RTO_MAX;
1280 return (tcp_time_stamp - tcp_sk(sk)->retrans_stamp) >= timeout;
1283 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1285 return sk->sk_send_head;
1288 static inline bool tcp_skb_is_last(const struct sock *sk,
1289 const struct sk_buff *skb)
1291 return skb_queue_is_last(&sk->sk_write_queue, skb);
1294 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1296 if (tcp_skb_is_last(sk, skb))
1297 sk->sk_send_head = NULL;
1299 sk->sk_send_head = tcp_write_queue_next(sk, skb);
1302 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1304 if (sk->sk_send_head == skb_unlinked)
1305 sk->sk_send_head = NULL;
1308 static inline void tcp_init_send_head(struct sock *sk)
1310 sk->sk_send_head = NULL;
1313 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1315 __skb_queue_tail(&sk->sk_write_queue, skb);
1318 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1320 __tcp_add_write_queue_tail(sk, skb);
1322 /* Queue it, remembering where we must start sending. */
1323 if (sk->sk_send_head == NULL) {
1324 sk->sk_send_head = skb;
1326 if (tcp_sk(sk)->highest_sack == NULL)
1327 tcp_sk(sk)->highest_sack = skb;
1331 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1333 __skb_queue_head(&sk->sk_write_queue, skb);
1336 /* Insert buff after skb on the write queue of sk. */
1337 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1338 struct sk_buff *buff,
1341 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1344 /* Insert new before skb on the write queue of sk. */
1345 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1346 struct sk_buff *skb,
1349 __skb_queue_before(&sk->sk_write_queue, skb, new);
1351 if (sk->sk_send_head == skb)
1352 sk->sk_send_head = new;
1355 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1357 __skb_unlink(skb, &sk->sk_write_queue);
1360 static inline int tcp_write_queue_empty(struct sock *sk)
1362 return skb_queue_empty(&sk->sk_write_queue);
1365 /* Start sequence of the highest skb with SACKed bit, valid only if
1366 * sacked > 0 or when the caller has ensured validity by itself.
1368 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1370 if (!tp->sacked_out)
1373 if (tp->highest_sack == NULL)
1376 return TCP_SKB_CB(tp->highest_sack)->seq;
1379 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1381 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1382 tcp_write_queue_next(sk, skb);
1385 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1387 return tcp_sk(sk)->highest_sack;
1390 static inline void tcp_highest_sack_reset(struct sock *sk)
1392 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1395 /* Called when old skb is about to be deleted (to be combined with new skb) */
1396 static inline void tcp_highest_sack_combine(struct sock *sk,
1397 struct sk_buff *old,
1398 struct sk_buff *new)
1400 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1401 tcp_sk(sk)->highest_sack = new;
1405 enum tcp_seq_states {
1406 TCP_SEQ_STATE_LISTENING,
1407 TCP_SEQ_STATE_OPENREQ,
1408 TCP_SEQ_STATE_ESTABLISHED,
1409 TCP_SEQ_STATE_TIME_WAIT,
1412 struct tcp_seq_afinfo {
1415 struct file_operations seq_fops;
1416 struct seq_operations seq_ops;
1419 struct tcp_iter_state {
1420 struct seq_net_private p;
1422 enum tcp_seq_states state;
1423 struct sock *syn_wait_sk;
1424 int bucket, sbucket, num, uid;
1427 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1428 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1430 extern struct request_sock_ops tcp_request_sock_ops;
1431 extern struct request_sock_ops tcp6_request_sock_ops;
1433 extern void tcp_v4_destroy_sock(struct sock *sk);
1435 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1436 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1437 extern struct sk_buff **tcp_gro_receive(struct sk_buff **head,
1438 struct sk_buff *skb);
1439 extern struct sk_buff **tcp4_gro_receive(struct sk_buff **head,
1440 struct sk_buff *skb);
1441 extern int tcp_gro_complete(struct sk_buff *skb);
1442 extern int tcp4_gro_complete(struct sk_buff *skb);
1444 #ifdef CONFIG_PROC_FS
1445 extern int tcp4_proc_init(void);
1446 extern void tcp4_proc_exit(void);
1449 /* TCP af-specific functions */
1450 struct tcp_sock_af_ops {
1451 #ifdef CONFIG_TCP_MD5SIG
1452 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1453 struct sock *addr_sk);
1454 int (*calc_md5_hash) (char *location,
1455 struct tcp_md5sig_key *md5,
1457 struct request_sock *req,
1458 struct sk_buff *skb);
1459 int (*md5_add) (struct sock *sk,
1460 struct sock *addr_sk,
1463 int (*md5_parse) (struct sock *sk,
1464 char __user *optval,
1469 struct tcp_request_sock_ops {
1470 #ifdef CONFIG_TCP_MD5SIG
1471 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1472 struct request_sock *req);
1473 int (*calc_md5_hash) (char *location,
1474 struct tcp_md5sig_key *md5,
1476 struct request_sock *req,
1477 struct sk_buff *skb);
1481 /* Using SHA1 for now, define some constants.
1483 #define COOKIE_DIGEST_WORDS (SHA_DIGEST_WORDS)
1484 #define COOKIE_MESSAGE_WORDS (SHA_MESSAGE_BYTES / 4)
1485 #define COOKIE_WORKSPACE_WORDS (COOKIE_DIGEST_WORDS + COOKIE_MESSAGE_WORDS)
1487 extern int tcp_cookie_generator(u32 *bakery);
1489 extern void tcp_v4_init(void);
1490 extern void tcp_init(void);