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>
45 #include <linux/seq_file.h>
47 extern struct inet_hashinfo tcp_hashinfo;
49 extern struct percpu_counter tcp_orphan_count;
50 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
52 #define MAX_TCP_HEADER (128 + MAX_HEADER)
53 #define MAX_TCP_OPTION_SPACE 40
56 * Never offer a window over 32767 without using window scaling. Some
57 * poor stacks do signed 16bit maths!
59 #define MAX_TCP_WINDOW 32767U
61 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
62 #define TCP_MIN_MSS 88U
64 /* Minimal RCV_MSS. */
65 #define TCP_MIN_RCVMSS 536U
67 /* The least MTU to use for probing */
68 #define TCP_BASE_MSS 512
70 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
71 #define TCP_FASTRETRANS_THRESH 3
73 /* Maximal reordering. */
74 #define TCP_MAX_REORDERING 127
76 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
77 #define TCP_MAX_QUICKACKS 16U
80 #define TCP_URG_VALID 0x0100
81 #define TCP_URG_NOTYET 0x0200
82 #define TCP_URG_READ 0x0400
84 #define TCP_RETR1 3 /*
85 * This is how many retries it does before it
86 * tries to figure out if the gateway is
87 * down. Minimal RFC value is 3; it corresponds
88 * to ~3sec-8min depending on RTO.
91 #define TCP_RETR2 15 /*
92 * This should take at least
93 * 90 minutes to time out.
94 * RFC1122 says that the limit is 100 sec.
95 * 15 is ~13-30min depending on RTO.
98 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
99 * connection: ~180sec is RFC minimum */
101 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
102 * connection: ~180sec is RFC minimum */
105 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
106 * socket. 7 is ~50sec-16min.
110 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
111 * state, about 60 seconds */
112 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
113 /* BSD style FIN_WAIT2 deadlock breaker.
114 * It used to be 3min, new value is 60sec,
115 * to combine FIN-WAIT-2 timeout with
119 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
121 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
122 #define TCP_ATO_MIN ((unsigned)(HZ/25))
124 #define TCP_DELACK_MIN 4U
125 #define TCP_ATO_MIN 4U
127 #define TCP_RTO_MAX ((unsigned)(120*HZ))
128 #define TCP_RTO_MIN ((unsigned)(HZ/5))
129 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
131 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
132 * for local resources.
135 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
136 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
137 #define TCP_KEEPALIVE_INTVL (75*HZ)
139 #define MAX_TCP_KEEPIDLE 32767
140 #define MAX_TCP_KEEPINTVL 32767
141 #define MAX_TCP_KEEPCNT 127
142 #define MAX_TCP_SYNCNT 127
144 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
146 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
147 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
148 * after this time. It should be equal
149 * (or greater than) TCP_TIMEWAIT_LEN
150 * to provide reliability equal to one
151 * provided by timewait state.
153 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
154 * timestamps. It must be less than
155 * minimal timewait lifetime.
161 #define TCPOPT_NOP 1 /* Padding */
162 #define TCPOPT_EOL 0 /* End of options */
163 #define TCPOPT_MSS 2 /* Segment size negotiating */
164 #define TCPOPT_WINDOW 3 /* Window scaling */
165 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
166 #define TCPOPT_SACK 5 /* SACK Block */
167 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
168 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
174 #define TCPOLEN_MSS 4
175 #define TCPOLEN_WINDOW 3
176 #define TCPOLEN_SACK_PERM 2
177 #define TCPOLEN_TIMESTAMP 10
178 #define TCPOLEN_MD5SIG 18
180 /* But this is what stacks really send out. */
181 #define TCPOLEN_TSTAMP_ALIGNED 12
182 #define TCPOLEN_WSCALE_ALIGNED 4
183 #define TCPOLEN_SACKPERM_ALIGNED 4
184 #define TCPOLEN_SACK_BASE 2
185 #define TCPOLEN_SACK_BASE_ALIGNED 4
186 #define TCPOLEN_SACK_PERBLOCK 8
187 #define TCPOLEN_MD5SIG_ALIGNED 20
188 #define TCPOLEN_MSS_ALIGNED 4
190 /* Flags in tp->nonagle */
191 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
192 #define TCP_NAGLE_CORK 2 /* Socket is corked */
193 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
195 extern struct inet_timewait_death_row tcp_death_row;
197 /* sysctl variables for tcp */
198 extern int sysctl_tcp_timestamps;
199 extern int sysctl_tcp_window_scaling;
200 extern int sysctl_tcp_sack;
201 extern int sysctl_tcp_fin_timeout;
202 extern int sysctl_tcp_keepalive_time;
203 extern int sysctl_tcp_keepalive_probes;
204 extern int sysctl_tcp_keepalive_intvl;
205 extern int sysctl_tcp_syn_retries;
206 extern int sysctl_tcp_synack_retries;
207 extern int sysctl_tcp_retries1;
208 extern int sysctl_tcp_retries2;
209 extern int sysctl_tcp_orphan_retries;
210 extern int sysctl_tcp_syncookies;
211 extern int sysctl_tcp_retrans_collapse;
212 extern int sysctl_tcp_stdurg;
213 extern int sysctl_tcp_rfc1337;
214 extern int sysctl_tcp_abort_on_overflow;
215 extern int sysctl_tcp_max_orphans;
216 extern int sysctl_tcp_fack;
217 extern int sysctl_tcp_reordering;
218 extern int sysctl_tcp_ecn;
219 extern int sysctl_tcp_dsack;
220 extern int sysctl_tcp_mem[3];
221 extern int sysctl_tcp_wmem[3];
222 extern int sysctl_tcp_rmem[3];
223 extern int sysctl_tcp_app_win;
224 extern int sysctl_tcp_adv_win_scale;
225 extern int sysctl_tcp_tw_reuse;
226 extern int sysctl_tcp_frto;
227 extern int sysctl_tcp_frto_response;
228 extern int sysctl_tcp_low_latency;
229 extern int sysctl_tcp_dma_copybreak;
230 extern int sysctl_tcp_nometrics_save;
231 extern int sysctl_tcp_moderate_rcvbuf;
232 extern int sysctl_tcp_tso_win_divisor;
233 extern int sysctl_tcp_abc;
234 extern int sysctl_tcp_mtu_probing;
235 extern int sysctl_tcp_base_mss;
236 extern int sysctl_tcp_workaround_signed_windows;
237 extern int sysctl_tcp_slow_start_after_idle;
238 extern int sysctl_tcp_max_ssthresh;
240 extern atomic_t tcp_memory_allocated;
241 extern struct percpu_counter tcp_sockets_allocated;
242 extern int tcp_memory_pressure;
245 * The next routines deal with comparing 32 bit unsigned ints
246 * and worry about wraparound (automatic with unsigned arithmetic).
249 static inline int before(__u32 seq1, __u32 seq2)
251 return (__s32)(seq1-seq2) < 0;
253 #define after(seq2, seq1) before(seq1, seq2)
255 /* is s2<=s1<=s3 ? */
256 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
258 return seq3 - seq2 >= seq1 - seq2;
261 static inline int tcp_too_many_orphans(struct sock *sk, int num)
263 return (num > sysctl_tcp_max_orphans) ||
264 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
265 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
268 /* syncookies: remember time of last synqueue overflow */
269 static inline void tcp_synq_overflow(struct sock *sk)
271 tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies;
274 /* syncookies: no recent synqueue overflow on this listening socket? */
275 static inline int tcp_synq_no_recent_overflow(const struct sock *sk)
277 unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp;
278 return time_after(jiffies, last_overflow + TCP_TIMEOUT_INIT);
281 extern struct proto tcp_prot;
283 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
284 #define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field)
285 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
286 #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
288 extern void tcp_v4_err(struct sk_buff *skb, u32);
290 extern void tcp_shutdown (struct sock *sk, int how);
292 extern int tcp_v4_rcv(struct sk_buff *skb);
294 extern int tcp_v4_remember_stamp(struct sock *sk);
296 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
298 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
299 struct msghdr *msg, size_t size);
300 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
302 extern int tcp_ioctl(struct sock *sk,
306 extern int tcp_rcv_state_process(struct sock *sk,
311 extern int tcp_rcv_established(struct sock *sk,
316 extern void tcp_rcv_space_adjust(struct sock *sk);
318 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
320 extern int tcp_twsk_unique(struct sock *sk,
321 struct sock *sktw, void *twp);
323 extern void tcp_twsk_destructor(struct sock *sk);
325 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
326 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
328 static inline void tcp_dec_quickack_mode(struct sock *sk,
329 const unsigned int pkts)
331 struct inet_connection_sock *icsk = inet_csk(sk);
333 if (icsk->icsk_ack.quick) {
334 if (pkts >= icsk->icsk_ack.quick) {
335 icsk->icsk_ack.quick = 0;
336 /* Leaving quickack mode we deflate ATO. */
337 icsk->icsk_ack.ato = TCP_ATO_MIN;
339 icsk->icsk_ack.quick -= pkts;
343 extern void tcp_enter_quickack_mode(struct sock *sk);
345 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
347 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
351 #define TCP_ECN_QUEUE_CWR 2
352 #define TCP_ECN_DEMAND_CWR 4
354 static __inline__ void
355 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
357 if (sysctl_tcp_ecn && th->ece && th->cwr)
358 inet_rsk(req)->ecn_ok = 1;
370 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
372 const struct tcphdr *th);
374 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
375 struct request_sock *req,
376 struct request_sock **prev);
377 extern int tcp_child_process(struct sock *parent,
379 struct sk_buff *skb);
380 extern int tcp_use_frto(struct sock *sk);
381 extern void tcp_enter_frto(struct sock *sk);
382 extern void tcp_enter_loss(struct sock *sk, int how);
383 extern void tcp_clear_retrans(struct tcp_sock *tp);
384 extern void tcp_update_metrics(struct sock *sk);
386 extern void tcp_close(struct sock *sk,
388 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
390 extern int tcp_getsockopt(struct sock *sk, int level,
394 extern int tcp_setsockopt(struct sock *sk, int level,
395 int optname, char __user *optval,
397 extern int compat_tcp_getsockopt(struct sock *sk,
398 int level, int optname,
399 char __user *optval, int __user *optlen);
400 extern int compat_tcp_setsockopt(struct sock *sk,
401 int level, int optname,
402 char __user *optval, int optlen);
403 extern void tcp_set_keepalive(struct sock *sk, int val);
404 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
406 size_t len, int nonblock,
407 int flags, int *addr_len);
409 extern void tcp_parse_options(struct sk_buff *skb,
410 struct tcp_options_received *opt_rx,
413 extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
416 * TCP v4 functions exported for the inet6 API
419 extern void tcp_v4_send_check(struct sock *sk, int len,
420 struct sk_buff *skb);
422 extern int tcp_v4_conn_request(struct sock *sk,
423 struct sk_buff *skb);
425 extern struct sock * tcp_create_openreq_child(struct sock *sk,
426 struct request_sock *req,
427 struct sk_buff *skb);
429 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
431 struct request_sock *req,
432 struct dst_entry *dst);
434 extern int tcp_v4_do_rcv(struct sock *sk,
435 struct sk_buff *skb);
437 extern int tcp_v4_connect(struct sock *sk,
438 struct sockaddr *uaddr,
441 extern int tcp_connect(struct sock *sk);
443 extern struct sk_buff * tcp_make_synack(struct sock *sk,
444 struct dst_entry *dst,
445 struct request_sock *req);
447 extern int tcp_disconnect(struct sock *sk, int flags);
450 /* From syncookies.c */
451 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
452 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
453 struct ip_options *opt);
454 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
457 extern __u32 cookie_init_timestamp(struct request_sock *req);
458 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
460 /* From net/ipv6/syncookies.c */
461 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
462 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
467 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
469 extern int tcp_may_send_now(struct sock *sk);
470 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
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_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
525 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
526 ntohl(TCP_FLAG_ACK) |
530 static inline void tcp_fast_path_on(struct tcp_sock *tp)
532 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
535 static inline void tcp_fast_path_check(struct sock *sk)
537 struct tcp_sock *tp = tcp_sk(sk);
539 if (skb_queue_empty(&tp->out_of_order_queue) &&
541 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
543 tcp_fast_path_on(tp);
546 /* Compute the actual receive window we are currently advertising.
547 * Rcv_nxt can be after the window if our peer push more data
548 * than the offered window.
550 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
552 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
559 /* Choose a new window, without checks for shrinking, and without
560 * scaling applied to the result. The caller does these things
561 * if necessary. This is a "raw" window selection.
563 extern u32 __tcp_select_window(struct sock *sk);
565 /* TCP timestamps are only 32-bits, this causes a slight
566 * complication on 64-bit systems since we store a snapshot
567 * of jiffies in the buffer control blocks below. We decided
568 * to use only the low 32-bits of jiffies and hide the ugly
569 * casts with the following macro.
571 #define tcp_time_stamp ((__u32)(jiffies))
573 /* This is what the send packet queuing engine uses to pass
574 * TCP per-packet control information to the transmission
575 * code. We also store the host-order sequence numbers in
576 * here too. This is 36 bytes on 32-bit architectures,
577 * 40 bytes on 64-bit machines, if this grows please adjust
578 * skbuff.h:skbuff->cb[xxx] size appropriately.
582 struct inet_skb_parm h4;
583 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
584 struct inet6_skb_parm h6;
586 } header; /* For incoming frames */
587 __u32 seq; /* Starting sequence number */
588 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
589 __u32 when; /* used to compute rtt's */
590 __u8 flags; /* TCP header flags. */
592 /* NOTE: These must match up to the flags byte in a
595 #define TCPCB_FLAG_FIN 0x01
596 #define TCPCB_FLAG_SYN 0x02
597 #define TCPCB_FLAG_RST 0x04
598 #define TCPCB_FLAG_PSH 0x08
599 #define TCPCB_FLAG_ACK 0x10
600 #define TCPCB_FLAG_URG 0x20
601 #define TCPCB_FLAG_ECE 0x40
602 #define TCPCB_FLAG_CWR 0x80
604 __u8 sacked; /* State flags for SACK/FACK. */
605 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
606 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
607 #define TCPCB_LOST 0x04 /* SKB is lost */
608 #define TCPCB_TAGBITS 0x07 /* All tag bits */
610 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
611 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
613 __u32 ack_seq; /* Sequence number ACK'd */
616 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
618 /* Due to TSO, an SKB can be composed of multiple actual
619 * packets. To keep these tracked properly, we use this.
621 static inline int tcp_skb_pcount(const struct sk_buff *skb)
623 return skb_shinfo(skb)->gso_segs;
626 /* This is valid iff tcp_skb_pcount() > 1. */
627 static inline int tcp_skb_mss(const struct sk_buff *skb)
629 return skb_shinfo(skb)->gso_size;
632 /* Events passed to congestion control interface */
634 CA_EVENT_TX_START, /* first transmit when no packets in flight */
635 CA_EVENT_CWND_RESTART, /* congestion window restart */
636 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
637 CA_EVENT_FRTO, /* fast recovery timeout */
638 CA_EVENT_LOSS, /* loss timeout */
639 CA_EVENT_FAST_ACK, /* in sequence ack */
640 CA_EVENT_SLOW_ACK, /* other ack */
644 * Interface for adding new TCP congestion control handlers
646 #define TCP_CA_NAME_MAX 16
647 #define TCP_CA_MAX 128
648 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
650 #define TCP_CONG_NON_RESTRICTED 0x1
651 #define TCP_CONG_RTT_STAMP 0x2
653 struct tcp_congestion_ops {
654 struct list_head list;
657 /* initialize private data (optional) */
658 void (*init)(struct sock *sk);
659 /* cleanup private data (optional) */
660 void (*release)(struct sock *sk);
662 /* return slow start threshold (required) */
663 u32 (*ssthresh)(struct sock *sk);
664 /* lower bound for congestion window (optional) */
665 u32 (*min_cwnd)(const struct sock *sk);
666 /* do new cwnd calculation (required) */
667 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
668 /* call before changing ca_state (optional) */
669 void (*set_state)(struct sock *sk, u8 new_state);
670 /* call when cwnd event occurs (optional) */
671 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
672 /* new value of cwnd after loss (optional) */
673 u32 (*undo_cwnd)(struct sock *sk);
674 /* hook for packet ack accounting (optional) */
675 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
676 /* get info for inet_diag (optional) */
677 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
679 char name[TCP_CA_NAME_MAX];
680 struct module *owner;
683 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
684 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
686 extern void tcp_init_congestion_control(struct sock *sk);
687 extern void tcp_cleanup_congestion_control(struct sock *sk);
688 extern int tcp_set_default_congestion_control(const char *name);
689 extern void tcp_get_default_congestion_control(char *name);
690 extern void tcp_get_available_congestion_control(char *buf, size_t len);
691 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
692 extern int tcp_set_allowed_congestion_control(char *allowed);
693 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
694 extern void tcp_slow_start(struct tcp_sock *tp);
695 extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w);
697 extern struct tcp_congestion_ops tcp_init_congestion_ops;
698 extern u32 tcp_reno_ssthresh(struct sock *sk);
699 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
700 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
701 extern struct tcp_congestion_ops tcp_reno;
703 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
705 struct inet_connection_sock *icsk = inet_csk(sk);
707 if (icsk->icsk_ca_ops->set_state)
708 icsk->icsk_ca_ops->set_state(sk, ca_state);
709 icsk->icsk_ca_state = ca_state;
712 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
714 const struct inet_connection_sock *icsk = inet_csk(sk);
716 if (icsk->icsk_ca_ops->cwnd_event)
717 icsk->icsk_ca_ops->cwnd_event(sk, event);
720 /* These functions determine how the current flow behaves in respect of SACK
721 * handling. SACK is negotiated with the peer, and therefore it can vary
722 * between different flows.
724 * tcp_is_sack - SACK enabled
725 * tcp_is_reno - No SACK
726 * tcp_is_fack - FACK enabled, implies SACK enabled
728 static inline int tcp_is_sack(const struct tcp_sock *tp)
730 return tp->rx_opt.sack_ok;
733 static inline int tcp_is_reno(const struct tcp_sock *tp)
735 return !tcp_is_sack(tp);
738 static inline int tcp_is_fack(const struct tcp_sock *tp)
740 return tp->rx_opt.sack_ok & 2;
743 static inline void tcp_enable_fack(struct tcp_sock *tp)
745 tp->rx_opt.sack_ok |= 2;
748 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
750 return tp->sacked_out + tp->lost_out;
753 /* This determines how many packets are "in the network" to the best
754 * of our knowledge. In many cases it is conservative, but where
755 * detailed information is available from the receiver (via SACK
756 * blocks etc.) we can make more aggressive calculations.
758 * Use this for decisions involving congestion control, use just
759 * tp->packets_out to determine if the send queue is empty or not.
761 * Read this equation as:
763 * "Packets sent once on transmission queue" MINUS
764 * "Packets left network, but not honestly ACKed yet" PLUS
765 * "Packets fast retransmitted"
767 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
769 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
772 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
773 * The exception is rate halving phase, when cwnd is decreasing towards
776 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
778 const struct tcp_sock *tp = tcp_sk(sk);
779 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
780 return tp->snd_ssthresh;
782 return max(tp->snd_ssthresh,
783 ((tp->snd_cwnd >> 1) +
784 (tp->snd_cwnd >> 2)));
787 /* Use define here intentionally to get WARN_ON location shown at the caller */
788 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
790 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
791 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
793 /* Slow start with delack produces 3 packets of burst, so that
794 * it is safe "de facto". This will be the default - same as
795 * the default reordering threshold - but if reordering increases,
796 * we must be able to allow cwnd to burst at least this much in order
797 * to not pull it back when holes are filled.
799 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
801 return tp->reordering;
804 /* Returns end sequence number of the receiver's advertised window */
805 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
807 return tp->snd_una + tp->snd_wnd;
809 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
811 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
812 const struct sk_buff *skb)
815 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
818 static inline void tcp_check_probe_timer(struct sock *sk)
820 struct tcp_sock *tp = tcp_sk(sk);
821 const struct inet_connection_sock *icsk = inet_csk(sk);
823 if (!tp->packets_out && !icsk->icsk_pending)
824 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
825 icsk->icsk_rto, TCP_RTO_MAX);
828 static inline void tcp_push_pending_frames(struct sock *sk)
830 struct tcp_sock *tp = tcp_sk(sk);
832 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle);
835 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)
840 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq)
846 * Calculate(/check) TCP checksum
848 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
849 __be32 daddr, __wsum base)
851 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
854 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
856 return __skb_checksum_complete(skb);
859 static inline int tcp_checksum_complete(struct sk_buff *skb)
861 return !skb_csum_unnecessary(skb) &&
862 __tcp_checksum_complete(skb);
865 /* Prequeue for VJ style copy to user, combined with checksumming. */
867 static inline void tcp_prequeue_init(struct tcp_sock *tp)
869 tp->ucopy.task = NULL;
871 tp->ucopy.memory = 0;
872 skb_queue_head_init(&tp->ucopy.prequeue);
873 #ifdef CONFIG_NET_DMA
874 tp->ucopy.dma_chan = NULL;
875 tp->ucopy.wakeup = 0;
876 tp->ucopy.pinned_list = NULL;
877 tp->ucopy.dma_cookie = 0;
881 /* Packet is added to VJ-style prequeue for processing in process
882 * context, if a reader task is waiting. Apparently, this exciting
883 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
884 * failed somewhere. Latency? Burstiness? Well, at least now we will
885 * see, why it failed. 8)8) --ANK
887 * NOTE: is this not too big to inline?
889 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
891 struct tcp_sock *tp = tcp_sk(sk);
893 if (sysctl_tcp_low_latency || !tp->ucopy.task)
896 __skb_queue_tail(&tp->ucopy.prequeue, skb);
897 tp->ucopy.memory += skb->truesize;
898 if (tp->ucopy.memory > sk->sk_rcvbuf) {
899 struct sk_buff *skb1;
901 BUG_ON(sock_owned_by_user(sk));
903 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
904 sk_backlog_rcv(sk, skb1);
905 NET_INC_STATS_BH(sock_net(sk),
906 LINUX_MIB_TCPPREQUEUEDROPPED);
909 tp->ucopy.memory = 0;
910 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
911 wake_up_interruptible_poll(sk->sk_sleep,
912 POLLIN | POLLRDNORM | POLLRDBAND);
913 if (!inet_csk_ack_scheduled(sk))
914 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
915 (3 * TCP_RTO_MIN) / 4,
925 static const char *statename[]={
926 "Unused","Established","Syn Sent","Syn Recv",
927 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
928 "Close Wait","Last ACK","Listen","Closing"
931 extern void tcp_set_state(struct sock *sk, int state);
933 extern void tcp_done(struct sock *sk);
935 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
938 rx_opt->num_sacks = 0;
941 /* Determine a window scaling and initial window to offer. */
942 extern void tcp_select_initial_window(int __space, __u32 mss,
943 __u32 *rcv_wnd, __u32 *window_clamp,
944 int wscale_ok, __u8 *rcv_wscale);
946 static inline int tcp_win_from_space(int space)
948 return sysctl_tcp_adv_win_scale<=0 ?
949 (space>>(-sysctl_tcp_adv_win_scale)) :
950 space - (space>>sysctl_tcp_adv_win_scale);
953 /* Note: caller must be prepared to deal with negative returns */
954 static inline int tcp_space(const struct sock *sk)
956 return tcp_win_from_space(sk->sk_rcvbuf -
957 atomic_read(&sk->sk_rmem_alloc));
960 static inline int tcp_full_space(const struct sock *sk)
962 return tcp_win_from_space(sk->sk_rcvbuf);
965 static inline void tcp_openreq_init(struct request_sock *req,
966 struct tcp_options_received *rx_opt,
969 struct inet_request_sock *ireq = inet_rsk(req);
971 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
973 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
974 req->mss = rx_opt->mss_clamp;
975 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
976 ireq->tstamp_ok = rx_opt->tstamp_ok;
977 ireq->sack_ok = rx_opt->sack_ok;
978 ireq->snd_wscale = rx_opt->snd_wscale;
979 ireq->wscale_ok = rx_opt->wscale_ok;
982 ireq->rmt_port = tcp_hdr(skb)->source;
983 ireq->loc_port = tcp_hdr(skb)->dest;
986 extern void tcp_enter_memory_pressure(struct sock *sk);
988 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
990 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
993 static inline int keepalive_time_when(const struct tcp_sock *tp)
995 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
998 static inline int tcp_fin_time(const struct sock *sk)
1000 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1001 const int rto = inet_csk(sk)->icsk_rto;
1003 if (fin_timeout < (rto << 2) - (rto >> 1))
1004 fin_timeout = (rto << 2) - (rto >> 1);
1009 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt,
1012 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
1014 if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))
1020 static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt,
1023 if (tcp_paws_check(rx_opt, 0))
1026 /* RST segments are not recommended to carry timestamp,
1027 and, if they do, it is recommended to ignore PAWS because
1028 "their cleanup function should take precedence over timestamps."
1029 Certainly, it is mistake. It is necessary to understand the reasons
1030 of this constraint to relax it: if peer reboots, clock may go
1031 out-of-sync and half-open connections will not be reset.
1032 Actually, the problem would be not existing if all
1033 the implementations followed draft about maintaining clock
1034 via reboots. Linux-2.2 DOES NOT!
1036 However, we can relax time bounds for RST segments to MSL.
1038 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1043 #define TCP_CHECK_TIMER(sk) do { } while (0)
1045 static inline void tcp_mib_init(struct net *net)
1048 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
1049 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1050 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1051 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
1055 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1057 tp->lost_skb_hint = NULL;
1058 tp->scoreboard_skb_hint = NULL;
1061 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1063 tcp_clear_retrans_hints_partial(tp);
1064 tp->retransmit_skb_hint = NULL;
1070 /* - key database */
1071 struct tcp_md5sig_key {
1076 struct tcp4_md5sig_key {
1077 struct tcp_md5sig_key base;
1081 struct tcp6_md5sig_key {
1082 struct tcp_md5sig_key base;
1084 u32 scope_id; /* XXX */
1086 struct in6_addr addr;
1090 struct tcp_md5sig_info {
1091 struct tcp4_md5sig_key *keys4;
1092 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1093 struct tcp6_md5sig_key *keys6;
1101 /* - pseudo header */
1102 struct tcp4_pseudohdr {
1110 struct tcp6_pseudohdr {
1111 struct in6_addr saddr;
1112 struct in6_addr daddr;
1114 __be32 protocol; /* including padding */
1117 union tcp_md5sum_block {
1118 struct tcp4_pseudohdr ip4;
1119 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1120 struct tcp6_pseudohdr ip6;
1124 /* - pool: digest algorithm, hash description and scratch buffer */
1125 struct tcp_md5sig_pool {
1126 struct hash_desc md5_desc;
1127 union tcp_md5sum_block md5_blk;
1130 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1133 extern int tcp_v4_md5_hash_skb(char *md5_hash,
1134 struct tcp_md5sig_key *key,
1136 struct request_sock *req,
1137 struct sk_buff *skb);
1139 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1140 struct sock *addr_sk);
1142 extern int tcp_v4_md5_do_add(struct sock *sk,
1147 extern int tcp_v4_md5_do_del(struct sock *sk,
1150 #ifdef CONFIG_TCP_MD5SIG
1151 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1152 &(struct tcp_md5sig_key) { \
1153 .key = (twsk)->tw_md5_key, \
1154 .keylen = (twsk)->tw_md5_keylen, \
1157 #define tcp_twsk_md5_key(twsk) NULL
1160 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1161 extern void tcp_free_md5sig_pool(void);
1163 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1164 extern void __tcp_put_md5sig_pool(void);
1165 extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *);
1166 extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *,
1167 unsigned header_len);
1168 extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1169 struct tcp_md5sig_key *key);
1172 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1174 int cpu = get_cpu();
1175 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1181 static inline void tcp_put_md5sig_pool(void)
1183 __tcp_put_md5sig_pool();
1187 /* write queue abstraction */
1188 static inline void tcp_write_queue_purge(struct sock *sk)
1190 struct sk_buff *skb;
1192 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1193 sk_wmem_free_skb(sk, skb);
1197 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1199 return skb_peek(&sk->sk_write_queue);
1202 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1204 return skb_peek_tail(&sk->sk_write_queue);
1207 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1209 return skb_queue_next(&sk->sk_write_queue, skb);
1212 static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_buff *skb)
1214 return skb_queue_prev(&sk->sk_write_queue, skb);
1217 #define tcp_for_write_queue(skb, sk) \
1218 skb_queue_walk(&(sk)->sk_write_queue, skb)
1220 #define tcp_for_write_queue_from(skb, sk) \
1221 skb_queue_walk_from(&(sk)->sk_write_queue, skb)
1223 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1224 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
1226 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1228 return sk->sk_send_head;
1231 static inline bool tcp_skb_is_last(const struct sock *sk,
1232 const struct sk_buff *skb)
1234 return skb_queue_is_last(&sk->sk_write_queue, skb);
1237 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1239 if (tcp_skb_is_last(sk, skb))
1240 sk->sk_send_head = NULL;
1242 sk->sk_send_head = tcp_write_queue_next(sk, skb);
1245 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1247 if (sk->sk_send_head == skb_unlinked)
1248 sk->sk_send_head = NULL;
1251 static inline void tcp_init_send_head(struct sock *sk)
1253 sk->sk_send_head = NULL;
1256 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1258 __skb_queue_tail(&sk->sk_write_queue, skb);
1261 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1263 __tcp_add_write_queue_tail(sk, skb);
1265 /* Queue it, remembering where we must start sending. */
1266 if (sk->sk_send_head == NULL) {
1267 sk->sk_send_head = skb;
1269 if (tcp_sk(sk)->highest_sack == NULL)
1270 tcp_sk(sk)->highest_sack = skb;
1274 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1276 __skb_queue_head(&sk->sk_write_queue, skb);
1279 /* Insert buff after skb on the write queue of sk. */
1280 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1281 struct sk_buff *buff,
1284 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1287 /* Insert new before skb on the write queue of sk. */
1288 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1289 struct sk_buff *skb,
1292 __skb_queue_before(&sk->sk_write_queue, skb, new);
1294 if (sk->sk_send_head == skb)
1295 sk->sk_send_head = new;
1298 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1300 __skb_unlink(skb, &sk->sk_write_queue);
1303 static inline int tcp_write_queue_empty(struct sock *sk)
1305 return skb_queue_empty(&sk->sk_write_queue);
1308 /* Start sequence of the highest skb with SACKed bit, valid only if
1309 * sacked > 0 or when the caller has ensured validity by itself.
1311 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1313 if (!tp->sacked_out)
1316 if (tp->highest_sack == NULL)
1319 return TCP_SKB_CB(tp->highest_sack)->seq;
1322 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1324 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1325 tcp_write_queue_next(sk, skb);
1328 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1330 return tcp_sk(sk)->highest_sack;
1333 static inline void tcp_highest_sack_reset(struct sock *sk)
1335 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1338 /* Called when old skb is about to be deleted (to be combined with new skb) */
1339 static inline void tcp_highest_sack_combine(struct sock *sk,
1340 struct sk_buff *old,
1341 struct sk_buff *new)
1343 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1344 tcp_sk(sk)->highest_sack = new;
1348 enum tcp_seq_states {
1349 TCP_SEQ_STATE_LISTENING,
1350 TCP_SEQ_STATE_OPENREQ,
1351 TCP_SEQ_STATE_ESTABLISHED,
1352 TCP_SEQ_STATE_TIME_WAIT,
1355 struct tcp_seq_afinfo {
1358 struct file_operations seq_fops;
1359 struct seq_operations seq_ops;
1362 struct tcp_iter_state {
1363 struct seq_net_private p;
1365 enum tcp_seq_states state;
1366 struct sock *syn_wait_sk;
1367 int bucket, sbucket, num, uid;
1370 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1371 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1373 extern struct request_sock_ops tcp_request_sock_ops;
1374 extern struct request_sock_ops tcp6_request_sock_ops;
1376 extern void tcp_v4_destroy_sock(struct sock *sk);
1378 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1379 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1380 extern struct sk_buff **tcp_gro_receive(struct sk_buff **head,
1381 struct sk_buff *skb);
1382 extern struct sk_buff **tcp4_gro_receive(struct sk_buff **head,
1383 struct sk_buff *skb);
1384 extern int tcp_gro_complete(struct sk_buff *skb);
1385 extern int tcp4_gro_complete(struct sk_buff *skb);
1387 #ifdef CONFIG_PROC_FS
1388 extern int tcp4_proc_init(void);
1389 extern void tcp4_proc_exit(void);
1392 /* TCP af-specific functions */
1393 struct tcp_sock_af_ops {
1394 #ifdef CONFIG_TCP_MD5SIG
1395 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1396 struct sock *addr_sk);
1397 int (*calc_md5_hash) (char *location,
1398 struct tcp_md5sig_key *md5,
1400 struct request_sock *req,
1401 struct sk_buff *skb);
1402 int (*md5_add) (struct sock *sk,
1403 struct sock *addr_sk,
1406 int (*md5_parse) (struct sock *sk,
1407 char __user *optval,
1412 struct tcp_request_sock_ops {
1413 #ifdef CONFIG_TCP_MD5SIG
1414 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1415 struct request_sock *req);
1419 extern void tcp_v4_init(void);
1420 extern void tcp_init(void);