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Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux...
[deliverable/linux.git] / include / net / tcp.h
1 /*
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.
5 *
6 * Definitions for the TCP module.
7 *
8 * Version: @(#)tcp.h 1.0.5 05/23/93
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 *
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.
17 */
18 #ifndef _TCP_H
19 #define _TCP_H
20
21 #define TCP_DEBUG 1
22 #define FASTRETRANS_DEBUG 1
23
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>
33
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>
39 #include <net/sock.h>
40 #include <net/snmp.h>
41 #include <net/ip.h>
42 #include <net/tcp_states.h>
43 #include <net/inet_ecn.h>
44
45 #include <linux/seq_file.h>
46
47 extern struct inet_hashinfo tcp_hashinfo;
48
49 extern atomic_t tcp_orphan_count;
50 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
51
52 #define MAX_TCP_HEADER (128 + MAX_HEADER)
53
54 /*
55 * Never offer a window over 32767 without using window scaling. Some
56 * poor stacks do signed 16bit maths!
57 */
58 #define MAX_TCP_WINDOW 32767U
59
60 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
61 #define TCP_MIN_MSS 88U
62
63 /* Minimal RCV_MSS. */
64 #define TCP_MIN_RCVMSS 536U
65
66 /* The least MTU to use for probing */
67 #define TCP_BASE_MSS 512
68
69 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
70 #define TCP_FASTRETRANS_THRESH 3
71
72 /* Maximal reordering. */
73 #define TCP_MAX_REORDERING 127
74
75 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
76 #define TCP_MAX_QUICKACKS 16U
77
78 /* urg_data states */
79 #define TCP_URG_VALID 0x0100
80 #define TCP_URG_NOTYET 0x0200
81 #define TCP_URG_READ 0x0400
82
83 #define TCP_RETR1 3 /*
84 * This is how many retries it does before it
85 * tries to figure out if the gateway is
86 * down. Minimal RFC value is 3; it corresponds
87 * to ~3sec-8min depending on RTO.
88 */
89
90 #define TCP_RETR2 15 /*
91 * This should take at least
92 * 90 minutes to time out.
93 * RFC1122 says that the limit is 100 sec.
94 * 15 is ~13-30min depending on RTO.
95 */
96
97 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
98 * connection: ~180sec is RFC minimum */
99
100 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
101 * connection: ~180sec is RFC minimum */
102
103
104 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
105 * socket. 7 is ~50sec-16min.
106 */
107
108
109 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
110 * state, about 60 seconds */
111 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
112 /* BSD style FIN_WAIT2 deadlock breaker.
113 * It used to be 3min, new value is 60sec,
114 * to combine FIN-WAIT-2 timeout with
115 * TIME-WAIT timer.
116 */
117
118 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
119 #if HZ >= 100
120 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
121 #define TCP_ATO_MIN ((unsigned)(HZ/25))
122 #else
123 #define TCP_DELACK_MIN 4U
124 #define TCP_ATO_MIN 4U
125 #endif
126 #define TCP_RTO_MAX ((unsigned)(120*HZ))
127 #define TCP_RTO_MIN ((unsigned)(HZ/5))
128 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
129
130 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
131 * for local resources.
132 */
133
134 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
135 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
136 #define TCP_KEEPALIVE_INTVL (75*HZ)
137
138 #define MAX_TCP_KEEPIDLE 32767
139 #define MAX_TCP_KEEPINTVL 32767
140 #define MAX_TCP_KEEPCNT 127
141 #define MAX_TCP_SYNCNT 127
142 #define MAX_TCP_ACCEPT_DEFERRED 65535
143
144 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
145
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.
152 */
153 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
154 * timestamps. It must be less than
155 * minimal timewait lifetime.
156 */
157 /*
158 * TCP option
159 */
160
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) */
169
170 /*
171 * TCP option lengths
172 */
173
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
179
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
189 /* Flags in tp->nonagle */
190 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
191 #define TCP_NAGLE_CORK 2 /* Socket is corked */
192 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
193
194 extern struct inet_timewait_death_row tcp_death_row;
195
196 /* sysctl variables for tcp */
197 extern int sysctl_tcp_timestamps;
198 extern int sysctl_tcp_window_scaling;
199 extern int sysctl_tcp_sack;
200 extern int sysctl_tcp_fin_timeout;
201 extern int sysctl_tcp_keepalive_time;
202 extern int sysctl_tcp_keepalive_probes;
203 extern int sysctl_tcp_keepalive_intvl;
204 extern int sysctl_tcp_syn_retries;
205 extern int sysctl_tcp_synack_retries;
206 extern int sysctl_tcp_retries1;
207 extern int sysctl_tcp_retries2;
208 extern int sysctl_tcp_orphan_retries;
209 extern int sysctl_tcp_syncookies;
210 extern int sysctl_tcp_retrans_collapse;
211 extern int sysctl_tcp_stdurg;
212 extern int sysctl_tcp_rfc1337;
213 extern int sysctl_tcp_abort_on_overflow;
214 extern int sysctl_tcp_max_orphans;
215 extern int sysctl_tcp_fack;
216 extern int sysctl_tcp_reordering;
217 extern int sysctl_tcp_ecn;
218 extern int sysctl_tcp_dsack;
219 extern int sysctl_tcp_mem[3];
220 extern int sysctl_tcp_wmem[3];
221 extern int sysctl_tcp_rmem[3];
222 extern int sysctl_tcp_app_win;
223 extern int sysctl_tcp_adv_win_scale;
224 extern int sysctl_tcp_tw_reuse;
225 extern int sysctl_tcp_frto;
226 extern int sysctl_tcp_frto_response;
227 extern int sysctl_tcp_low_latency;
228 extern int sysctl_tcp_dma_copybreak;
229 extern int sysctl_tcp_nometrics_save;
230 extern int sysctl_tcp_moderate_rcvbuf;
231 extern int sysctl_tcp_tso_win_divisor;
232 extern int sysctl_tcp_abc;
233 extern int sysctl_tcp_mtu_probing;
234 extern int sysctl_tcp_base_mss;
235 extern int sysctl_tcp_workaround_signed_windows;
236 extern int sysctl_tcp_slow_start_after_idle;
237 extern int sysctl_tcp_max_ssthresh;
238
239 extern atomic_t tcp_memory_allocated;
240 extern atomic_t tcp_sockets_allocated;
241 extern int tcp_memory_pressure;
242
243 /*
244 * The next routines deal with comparing 32 bit unsigned ints
245 * and worry about wraparound (automatic with unsigned arithmetic).
246 */
247
248 static inline int before(__u32 seq1, __u32 seq2)
249 {
250 return (__s32)(seq1-seq2) < 0;
251 }
252 #define after(seq2, seq1) before(seq1, seq2)
253
254 /* is s2<=s1<=s3 ? */
255 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
256 {
257 return seq3 - seq2 >= seq1 - seq2;
258 }
259
260 static inline int tcp_too_many_orphans(struct sock *sk, int num)
261 {
262 return (num > sysctl_tcp_max_orphans) ||
263 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
264 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
265 }
266
267 extern struct proto tcp_prot;
268
269 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
270 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
271 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
272 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
273 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
274 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
275 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
276
277 extern void tcp_v4_err(struct sk_buff *skb, u32);
278
279 extern void tcp_shutdown (struct sock *sk, int how);
280
281 extern int tcp_v4_rcv(struct sk_buff *skb);
282
283 extern int tcp_v4_remember_stamp(struct sock *sk);
284
285 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
286
287 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
288 struct msghdr *msg, size_t size);
289 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
290
291 extern int tcp_ioctl(struct sock *sk,
292 int cmd,
293 unsigned long arg);
294
295 extern int tcp_rcv_state_process(struct sock *sk,
296 struct sk_buff *skb,
297 struct tcphdr *th,
298 unsigned len);
299
300 extern int tcp_rcv_established(struct sock *sk,
301 struct sk_buff *skb,
302 struct tcphdr *th,
303 unsigned len);
304
305 extern void tcp_rcv_space_adjust(struct sock *sk);
306
307 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
308
309 extern int tcp_twsk_unique(struct sock *sk,
310 struct sock *sktw, void *twp);
311
312 extern void tcp_twsk_destructor(struct sock *sk);
313
314 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
315 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
316
317 static inline void tcp_dec_quickack_mode(struct sock *sk,
318 const unsigned int pkts)
319 {
320 struct inet_connection_sock *icsk = inet_csk(sk);
321
322 if (icsk->icsk_ack.quick) {
323 if (pkts >= icsk->icsk_ack.quick) {
324 icsk->icsk_ack.quick = 0;
325 /* Leaving quickack mode we deflate ATO. */
326 icsk->icsk_ack.ato = TCP_ATO_MIN;
327 } else
328 icsk->icsk_ack.quick -= pkts;
329 }
330 }
331
332 extern void tcp_enter_quickack_mode(struct sock *sk);
333
334 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
335 {
336 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
337 }
338
339 #define TCP_ECN_OK 1
340 #define TCP_ECN_QUEUE_CWR 2
341 #define TCP_ECN_DEMAND_CWR 4
342
343 static __inline__ void
344 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
345 {
346 if (sysctl_tcp_ecn && th->ece && th->cwr)
347 inet_rsk(req)->ecn_ok = 1;
348 }
349
350 enum tcp_tw_status
351 {
352 TCP_TW_SUCCESS = 0,
353 TCP_TW_RST = 1,
354 TCP_TW_ACK = 2,
355 TCP_TW_SYN = 3
356 };
357
358
359 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
360 struct sk_buff *skb,
361 const struct tcphdr *th);
362
363 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
364 struct request_sock *req,
365 struct request_sock **prev);
366 extern int tcp_child_process(struct sock *parent,
367 struct sock *child,
368 struct sk_buff *skb);
369 extern int tcp_use_frto(struct sock *sk);
370 extern void tcp_enter_frto(struct sock *sk);
371 extern void tcp_enter_loss(struct sock *sk, int how);
372 extern void tcp_clear_retrans(struct tcp_sock *tp);
373 extern void tcp_update_metrics(struct sock *sk);
374
375 extern void tcp_close(struct sock *sk,
376 long timeout);
377 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
378
379 extern int tcp_getsockopt(struct sock *sk, int level,
380 int optname,
381 char __user *optval,
382 int __user *optlen);
383 extern int tcp_setsockopt(struct sock *sk, int level,
384 int optname, char __user *optval,
385 int optlen);
386 extern int compat_tcp_getsockopt(struct sock *sk,
387 int level, int optname,
388 char __user *optval, int __user *optlen);
389 extern int compat_tcp_setsockopt(struct sock *sk,
390 int level, int optname,
391 char __user *optval, int optlen);
392 extern void tcp_set_keepalive(struct sock *sk, int val);
393 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
394 struct msghdr *msg,
395 size_t len, int nonblock,
396 int flags, int *addr_len);
397
398 extern void tcp_parse_options(struct sk_buff *skb,
399 struct tcp_options_received *opt_rx,
400 int estab);
401
402 /*
403 * TCP v4 functions exported for the inet6 API
404 */
405
406 extern void tcp_v4_send_check(struct sock *sk, int len,
407 struct sk_buff *skb);
408
409 extern int tcp_v4_conn_request(struct sock *sk,
410 struct sk_buff *skb);
411
412 extern struct sock * tcp_create_openreq_child(struct sock *sk,
413 struct request_sock *req,
414 struct sk_buff *skb);
415
416 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
417 struct sk_buff *skb,
418 struct request_sock *req,
419 struct dst_entry *dst);
420
421 extern int tcp_v4_do_rcv(struct sock *sk,
422 struct sk_buff *skb);
423
424 extern int tcp_v4_connect(struct sock *sk,
425 struct sockaddr *uaddr,
426 int addr_len);
427
428 extern int tcp_connect(struct sock *sk);
429
430 extern struct sk_buff * tcp_make_synack(struct sock *sk,
431 struct dst_entry *dst,
432 struct request_sock *req);
433
434 extern int tcp_disconnect(struct sock *sk, int flags);
435
436
437 /* From syncookies.c */
438 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
439 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
440 struct ip_options *opt);
441 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
442 __u16 *mss);
443
444 extern __u32 cookie_init_timestamp(struct request_sock *req);
445 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
446
447 /* From net/ipv6/syncookies.c */
448 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
449 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
450 __u16 *mss);
451
452 /* tcp_output.c */
453
454 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
455 int nonagle);
456 extern int tcp_may_send_now(struct sock *sk);
457 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
458 extern void tcp_xmit_retransmit_queue(struct sock *);
459 extern void tcp_simple_retransmit(struct sock *);
460 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
461 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
462
463 extern void tcp_send_probe0(struct sock *);
464 extern void tcp_send_partial(struct sock *);
465 extern int tcp_write_wakeup(struct sock *);
466 extern void tcp_send_fin(struct sock *sk);
467 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
468 extern int tcp_send_synack(struct sock *);
469 extern void tcp_push_one(struct sock *, unsigned int mss_now);
470 extern void tcp_send_ack(struct sock *sk);
471 extern void tcp_send_delayed_ack(struct sock *sk);
472
473 /* tcp_input.c */
474 extern void tcp_cwnd_application_limited(struct sock *sk);
475
476 /* tcp_timer.c */
477 extern void tcp_init_xmit_timers(struct sock *);
478 static inline void tcp_clear_xmit_timers(struct sock *sk)
479 {
480 inet_csk_clear_xmit_timers(sk);
481 }
482
483 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
484 extern unsigned int tcp_current_mss(struct sock *sk, int large);
485
486 /* tcp.c */
487 extern void tcp_get_info(struct sock *, struct tcp_info *);
488
489 /* Read 'sendfile()'-style from a TCP socket */
490 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
491 unsigned int, size_t);
492 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
493 sk_read_actor_t recv_actor);
494
495 extern void tcp_initialize_rcv_mss(struct sock *sk);
496
497 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
498 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
499 extern void tcp_mtup_init(struct sock *sk);
500
501 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
502 {
503 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
504 ntohl(TCP_FLAG_ACK) |
505 snd_wnd);
506 }
507
508 static inline void tcp_fast_path_on(struct tcp_sock *tp)
509 {
510 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
511 }
512
513 static inline void tcp_fast_path_check(struct sock *sk)
514 {
515 struct tcp_sock *tp = tcp_sk(sk);
516
517 if (skb_queue_empty(&tp->out_of_order_queue) &&
518 tp->rcv_wnd &&
519 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
520 !tp->urg_data)
521 tcp_fast_path_on(tp);
522 }
523
524 /* Compute the actual receive window we are currently advertising.
525 * Rcv_nxt can be after the window if our peer push more data
526 * than the offered window.
527 */
528 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
529 {
530 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
531
532 if (win < 0)
533 win = 0;
534 return (u32) win;
535 }
536
537 /* Choose a new window, without checks for shrinking, and without
538 * scaling applied to the result. The caller does these things
539 * if necessary. This is a "raw" window selection.
540 */
541 extern u32 __tcp_select_window(struct sock *sk);
542
543 /* TCP timestamps are only 32-bits, this causes a slight
544 * complication on 64-bit systems since we store a snapshot
545 * of jiffies in the buffer control blocks below. We decided
546 * to use only the low 32-bits of jiffies and hide the ugly
547 * casts with the following macro.
548 */
549 #define tcp_time_stamp ((__u32)(jiffies))
550
551 /* This is what the send packet queuing engine uses to pass
552 * TCP per-packet control information to the transmission
553 * code. We also store the host-order sequence numbers in
554 * here too. This is 36 bytes on 32-bit architectures,
555 * 40 bytes on 64-bit machines, if this grows please adjust
556 * skbuff.h:skbuff->cb[xxx] size appropriately.
557 */
558 struct tcp_skb_cb {
559 union {
560 struct inet_skb_parm h4;
561 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
562 struct inet6_skb_parm h6;
563 #endif
564 } header; /* For incoming frames */
565 __u32 seq; /* Starting sequence number */
566 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
567 __u32 when; /* used to compute rtt's */
568 __u8 flags; /* TCP header flags. */
569
570 /* NOTE: These must match up to the flags byte in a
571 * real TCP header.
572 */
573 #define TCPCB_FLAG_FIN 0x01
574 #define TCPCB_FLAG_SYN 0x02
575 #define TCPCB_FLAG_RST 0x04
576 #define TCPCB_FLAG_PSH 0x08
577 #define TCPCB_FLAG_ACK 0x10
578 #define TCPCB_FLAG_URG 0x20
579 #define TCPCB_FLAG_ECE 0x40
580 #define TCPCB_FLAG_CWR 0x80
581
582 __u8 sacked; /* State flags for SACK/FACK. */
583 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
584 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
585 #define TCPCB_LOST 0x04 /* SKB is lost */
586 #define TCPCB_TAGBITS 0x07 /* All tag bits */
587
588 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
589 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
590
591 __u16 urg_ptr; /* Valid w/URG flags is set. */
592 __u32 ack_seq; /* Sequence number ACK'd */
593 };
594
595 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
596
597 /* Due to TSO, an SKB can be composed of multiple actual
598 * packets. To keep these tracked properly, we use this.
599 */
600 static inline int tcp_skb_pcount(const struct sk_buff *skb)
601 {
602 return skb_shinfo(skb)->gso_segs;
603 }
604
605 /* This is valid iff tcp_skb_pcount() > 1. */
606 static inline int tcp_skb_mss(const struct sk_buff *skb)
607 {
608 return skb_shinfo(skb)->gso_size;
609 }
610
611 static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
612 {
613 if (*count) {
614 *count -= decr;
615 if ((int)*count < 0)
616 *count = 0;
617 }
618 }
619
620 static inline void tcp_dec_pcount_approx(__u32 *count,
621 const struct sk_buff *skb)
622 {
623 tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
624 }
625
626 /* Events passed to congestion control interface */
627 enum tcp_ca_event {
628 CA_EVENT_TX_START, /* first transmit when no packets in flight */
629 CA_EVENT_CWND_RESTART, /* congestion window restart */
630 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
631 CA_EVENT_FRTO, /* fast recovery timeout */
632 CA_EVENT_LOSS, /* loss timeout */
633 CA_EVENT_FAST_ACK, /* in sequence ack */
634 CA_EVENT_SLOW_ACK, /* other ack */
635 };
636
637 /*
638 * Interface for adding new TCP congestion control handlers
639 */
640 #define TCP_CA_NAME_MAX 16
641 #define TCP_CA_MAX 128
642 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
643
644 #define TCP_CONG_NON_RESTRICTED 0x1
645 #define TCP_CONG_RTT_STAMP 0x2
646
647 struct tcp_congestion_ops {
648 struct list_head list;
649 unsigned long flags;
650
651 /* initialize private data (optional) */
652 void (*init)(struct sock *sk);
653 /* cleanup private data (optional) */
654 void (*release)(struct sock *sk);
655
656 /* return slow start threshold (required) */
657 u32 (*ssthresh)(struct sock *sk);
658 /* lower bound for congestion window (optional) */
659 u32 (*min_cwnd)(const struct sock *sk);
660 /* do new cwnd calculation (required) */
661 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
662 /* call before changing ca_state (optional) */
663 void (*set_state)(struct sock *sk, u8 new_state);
664 /* call when cwnd event occurs (optional) */
665 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
666 /* new value of cwnd after loss (optional) */
667 u32 (*undo_cwnd)(struct sock *sk);
668 /* hook for packet ack accounting (optional) */
669 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
670 /* get info for inet_diag (optional) */
671 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
672
673 char name[TCP_CA_NAME_MAX];
674 struct module *owner;
675 };
676
677 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
678 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
679
680 extern void tcp_init_congestion_control(struct sock *sk);
681 extern void tcp_cleanup_congestion_control(struct sock *sk);
682 extern int tcp_set_default_congestion_control(const char *name);
683 extern void tcp_get_default_congestion_control(char *name);
684 extern void tcp_get_available_congestion_control(char *buf, size_t len);
685 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
686 extern int tcp_set_allowed_congestion_control(char *allowed);
687 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
688 extern void tcp_slow_start(struct tcp_sock *tp);
689
690 extern struct tcp_congestion_ops tcp_init_congestion_ops;
691 extern u32 tcp_reno_ssthresh(struct sock *sk);
692 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
693 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
694 extern struct tcp_congestion_ops tcp_reno;
695
696 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
697 {
698 struct inet_connection_sock *icsk = inet_csk(sk);
699
700 if (icsk->icsk_ca_ops->set_state)
701 icsk->icsk_ca_ops->set_state(sk, ca_state);
702 icsk->icsk_ca_state = ca_state;
703 }
704
705 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
706 {
707 const struct inet_connection_sock *icsk = inet_csk(sk);
708
709 if (icsk->icsk_ca_ops->cwnd_event)
710 icsk->icsk_ca_ops->cwnd_event(sk, event);
711 }
712
713 /* These functions determine how the current flow behaves in respect of SACK
714 * handling. SACK is negotiated with the peer, and therefore it can vary
715 * between different flows.
716 *
717 * tcp_is_sack - SACK enabled
718 * tcp_is_reno - No SACK
719 * tcp_is_fack - FACK enabled, implies SACK enabled
720 */
721 static inline int tcp_is_sack(const struct tcp_sock *tp)
722 {
723 return tp->rx_opt.sack_ok;
724 }
725
726 static inline int tcp_is_reno(const struct tcp_sock *tp)
727 {
728 return !tcp_is_sack(tp);
729 }
730
731 static inline int tcp_is_fack(const struct tcp_sock *tp)
732 {
733 return tp->rx_opt.sack_ok & 2;
734 }
735
736 static inline void tcp_enable_fack(struct tcp_sock *tp)
737 {
738 tp->rx_opt.sack_ok |= 2;
739 }
740
741 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
742 {
743 return tp->sacked_out + tp->lost_out;
744 }
745
746 /* This determines how many packets are "in the network" to the best
747 * of our knowledge. In many cases it is conservative, but where
748 * detailed information is available from the receiver (via SACK
749 * blocks etc.) we can make more aggressive calculations.
750 *
751 * Use this for decisions involving congestion control, use just
752 * tp->packets_out to determine if the send queue is empty or not.
753 *
754 * Read this equation as:
755 *
756 * "Packets sent once on transmission queue" MINUS
757 * "Packets left network, but not honestly ACKed yet" PLUS
758 * "Packets fast retransmitted"
759 */
760 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
761 {
762 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
763 }
764
765 extern int tcp_limit_reno_sacked(struct tcp_sock *tp);
766
767 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
768 * The exception is rate halving phase, when cwnd is decreasing towards
769 * ssthresh.
770 */
771 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
772 {
773 const struct tcp_sock *tp = tcp_sk(sk);
774 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
775 return tp->snd_ssthresh;
776 else
777 return max(tp->snd_ssthresh,
778 ((tp->snd_cwnd >> 1) +
779 (tp->snd_cwnd >> 2)));
780 }
781
782 /* Use define here intentionally to get WARN_ON location shown at the caller */
783 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
784
785 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
786 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
787
788 /* Slow start with delack produces 3 packets of burst, so that
789 * it is safe "de facto". This will be the default - same as
790 * the default reordering threshold - but if reordering increases,
791 * we must be able to allow cwnd to burst at least this much in order
792 * to not pull it back when holes are filled.
793 */
794 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
795 {
796 return tp->reordering;
797 }
798
799 /* Returns end sequence number of the receiver's advertised window */
800 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
801 {
802 return tp->snd_una + tp->snd_wnd;
803 }
804 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
805
806 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
807 const struct sk_buff *skb)
808 {
809 if (skb->len < mss)
810 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
811 }
812
813 static inline void tcp_check_probe_timer(struct sock *sk)
814 {
815 struct tcp_sock *tp = tcp_sk(sk);
816 const struct inet_connection_sock *icsk = inet_csk(sk);
817
818 if (!tp->packets_out && !icsk->icsk_pending)
819 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
820 icsk->icsk_rto, TCP_RTO_MAX);
821 }
822
823 static inline void tcp_push_pending_frames(struct sock *sk)
824 {
825 struct tcp_sock *tp = tcp_sk(sk);
826
827 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
828 }
829
830 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
831 {
832 tp->snd_wl1 = seq;
833 }
834
835 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
836 {
837 tp->snd_wl1 = seq;
838 }
839
840 /*
841 * Calculate(/check) TCP checksum
842 */
843 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
844 __be32 daddr, __wsum base)
845 {
846 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
847 }
848
849 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
850 {
851 return __skb_checksum_complete(skb);
852 }
853
854 static inline int tcp_checksum_complete(struct sk_buff *skb)
855 {
856 return !skb_csum_unnecessary(skb) &&
857 __tcp_checksum_complete(skb);
858 }
859
860 /* Prequeue for VJ style copy to user, combined with checksumming. */
861
862 static inline void tcp_prequeue_init(struct tcp_sock *tp)
863 {
864 tp->ucopy.task = NULL;
865 tp->ucopy.len = 0;
866 tp->ucopy.memory = 0;
867 skb_queue_head_init(&tp->ucopy.prequeue);
868 #ifdef CONFIG_NET_DMA
869 tp->ucopy.dma_chan = NULL;
870 tp->ucopy.wakeup = 0;
871 tp->ucopy.pinned_list = NULL;
872 tp->ucopy.dma_cookie = 0;
873 #endif
874 }
875
876 /* Packet is added to VJ-style prequeue for processing in process
877 * context, if a reader task is waiting. Apparently, this exciting
878 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
879 * failed somewhere. Latency? Burstiness? Well, at least now we will
880 * see, why it failed. 8)8) --ANK
881 *
882 * NOTE: is this not too big to inline?
883 */
884 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
885 {
886 struct tcp_sock *tp = tcp_sk(sk);
887
888 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
889 __skb_queue_tail(&tp->ucopy.prequeue, skb);
890 tp->ucopy.memory += skb->truesize;
891 if (tp->ucopy.memory > sk->sk_rcvbuf) {
892 struct sk_buff *skb1;
893
894 BUG_ON(sock_owned_by_user(sk));
895
896 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
897 sk->sk_backlog_rcv(sk, skb1);
898 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
899 }
900
901 tp->ucopy.memory = 0;
902 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
903 wake_up_interruptible(sk->sk_sleep);
904 if (!inet_csk_ack_scheduled(sk))
905 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
906 (3 * TCP_RTO_MIN) / 4,
907 TCP_RTO_MAX);
908 }
909 return 1;
910 }
911 return 0;
912 }
913
914
915 #undef STATE_TRACE
916
917 #ifdef STATE_TRACE
918 static const char *statename[]={
919 "Unused","Established","Syn Sent","Syn Recv",
920 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
921 "Close Wait","Last ACK","Listen","Closing"
922 };
923 #endif
924 extern void tcp_set_state(struct sock *sk, int state);
925
926 extern void tcp_done(struct sock *sk);
927
928 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
929 {
930 rx_opt->dsack = 0;
931 rx_opt->eff_sacks = 0;
932 rx_opt->num_sacks = 0;
933 }
934
935 /* Determine a window scaling and initial window to offer. */
936 extern void tcp_select_initial_window(int __space, __u32 mss,
937 __u32 *rcv_wnd, __u32 *window_clamp,
938 int wscale_ok, __u8 *rcv_wscale);
939
940 static inline int tcp_win_from_space(int space)
941 {
942 return sysctl_tcp_adv_win_scale<=0 ?
943 (space>>(-sysctl_tcp_adv_win_scale)) :
944 space - (space>>sysctl_tcp_adv_win_scale);
945 }
946
947 /* Note: caller must be prepared to deal with negative returns */
948 static inline int tcp_space(const struct sock *sk)
949 {
950 return tcp_win_from_space(sk->sk_rcvbuf -
951 atomic_read(&sk->sk_rmem_alloc));
952 }
953
954 static inline int tcp_full_space(const struct sock *sk)
955 {
956 return tcp_win_from_space(sk->sk_rcvbuf);
957 }
958
959 static inline void tcp_openreq_init(struct request_sock *req,
960 struct tcp_options_received *rx_opt,
961 struct sk_buff *skb)
962 {
963 struct inet_request_sock *ireq = inet_rsk(req);
964
965 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
966 req->cookie_ts = 0;
967 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
968 req->mss = rx_opt->mss_clamp;
969 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
970 ireq->tstamp_ok = rx_opt->tstamp_ok;
971 ireq->sack_ok = rx_opt->sack_ok;
972 ireq->snd_wscale = rx_opt->snd_wscale;
973 ireq->wscale_ok = rx_opt->wscale_ok;
974 ireq->acked = 0;
975 ireq->ecn_ok = 0;
976 ireq->rmt_port = tcp_hdr(skb)->source;
977 }
978
979 extern void tcp_enter_memory_pressure(void);
980
981 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
982 {
983 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
984 }
985
986 static inline int keepalive_time_when(const struct tcp_sock *tp)
987 {
988 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
989 }
990
991 static inline int tcp_fin_time(const struct sock *sk)
992 {
993 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
994 const int rto = inet_csk(sk)->icsk_rto;
995
996 if (fin_timeout < (rto << 2) - (rto >> 1))
997 fin_timeout = (rto << 2) - (rto >> 1);
998
999 return fin_timeout;
1000 }
1001
1002 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1003 {
1004 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1005 return 0;
1006 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1007 return 0;
1008
1009 /* RST segments are not recommended to carry timestamp,
1010 and, if they do, it is recommended to ignore PAWS because
1011 "their cleanup function should take precedence over timestamps."
1012 Certainly, it is mistake. It is necessary to understand the reasons
1013 of this constraint to relax it: if peer reboots, clock may go
1014 out-of-sync and half-open connections will not be reset.
1015 Actually, the problem would be not existing if all
1016 the implementations followed draft about maintaining clock
1017 via reboots. Linux-2.2 DOES NOT!
1018
1019 However, we can relax time bounds for RST segments to MSL.
1020 */
1021 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1022 return 0;
1023 return 1;
1024 }
1025
1026 #define TCP_CHECK_TIMER(sk) do { } while (0)
1027
1028 static inline void tcp_mib_init(void)
1029 {
1030 /* See RFC 2012 */
1031 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1032 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1033 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1034 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
1035 }
1036
1037 /* from STCP */
1038 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1039 {
1040 tp->lost_skb_hint = NULL;
1041 tp->scoreboard_skb_hint = NULL;
1042 tp->retransmit_skb_hint = NULL;
1043 tp->forward_skb_hint = NULL;
1044 }
1045
1046 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1047 {
1048 tcp_clear_retrans_hints_partial(tp);
1049 }
1050
1051 /* MD5 Signature */
1052 struct crypto_hash;
1053
1054 /* - key database */
1055 struct tcp_md5sig_key {
1056 u8 *key;
1057 u8 keylen;
1058 };
1059
1060 struct tcp4_md5sig_key {
1061 struct tcp_md5sig_key base;
1062 __be32 addr;
1063 };
1064
1065 struct tcp6_md5sig_key {
1066 struct tcp_md5sig_key base;
1067 #if 0
1068 u32 scope_id; /* XXX */
1069 #endif
1070 struct in6_addr addr;
1071 };
1072
1073 /* - sock block */
1074 struct tcp_md5sig_info {
1075 struct tcp4_md5sig_key *keys4;
1076 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1077 struct tcp6_md5sig_key *keys6;
1078 u32 entries6;
1079 u32 alloced6;
1080 #endif
1081 u32 entries4;
1082 u32 alloced4;
1083 };
1084
1085 /* - pseudo header */
1086 struct tcp4_pseudohdr {
1087 __be32 saddr;
1088 __be32 daddr;
1089 __u8 pad;
1090 __u8 protocol;
1091 __be16 len;
1092 };
1093
1094 struct tcp6_pseudohdr {
1095 struct in6_addr saddr;
1096 struct in6_addr daddr;
1097 __be32 len;
1098 __be32 protocol; /* including padding */
1099 };
1100
1101 union tcp_md5sum_block {
1102 struct tcp4_pseudohdr ip4;
1103 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1104 struct tcp6_pseudohdr ip6;
1105 #endif
1106 };
1107
1108 /* - pool: digest algorithm, hash description and scratch buffer */
1109 struct tcp_md5sig_pool {
1110 struct hash_desc md5_desc;
1111 union tcp_md5sum_block md5_blk;
1112 };
1113
1114 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1115
1116 /* - functions */
1117 extern int tcp_v4_calc_md5_hash(char *md5_hash,
1118 struct tcp_md5sig_key *key,
1119 struct sock *sk,
1120 struct dst_entry *dst,
1121 struct request_sock *req,
1122 struct tcphdr *th,
1123 int protocol,
1124 unsigned int tcplen);
1125 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1126 struct sock *addr_sk);
1127
1128 extern int tcp_v4_md5_do_add(struct sock *sk,
1129 __be32 addr,
1130 u8 *newkey,
1131 u8 newkeylen);
1132
1133 extern int tcp_v4_md5_do_del(struct sock *sk,
1134 __be32 addr);
1135
1136 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1137 extern void tcp_free_md5sig_pool(void);
1138
1139 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1140 extern void __tcp_put_md5sig_pool(void);
1141
1142 static inline
1143 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1144 {
1145 int cpu = get_cpu();
1146 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1147 if (!ret)
1148 put_cpu();
1149 return ret;
1150 }
1151
1152 static inline void tcp_put_md5sig_pool(void)
1153 {
1154 __tcp_put_md5sig_pool();
1155 put_cpu();
1156 }
1157
1158 /* write queue abstraction */
1159 static inline void tcp_write_queue_purge(struct sock *sk)
1160 {
1161 struct sk_buff *skb;
1162
1163 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1164 sk_wmem_free_skb(sk, skb);
1165 sk_mem_reclaim(sk);
1166 }
1167
1168 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1169 {
1170 struct sk_buff *skb = sk->sk_write_queue.next;
1171 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1172 return NULL;
1173 return skb;
1174 }
1175
1176 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1177 {
1178 struct sk_buff *skb = sk->sk_write_queue.prev;
1179 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1180 return NULL;
1181 return skb;
1182 }
1183
1184 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1185 {
1186 return skb->next;
1187 }
1188
1189 #define tcp_for_write_queue(skb, sk) \
1190 for (skb = (sk)->sk_write_queue.next; \
1191 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1192 skb = skb->next)
1193
1194 #define tcp_for_write_queue_from(skb, sk) \
1195 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\
1196 skb = skb->next)
1197
1198 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1199 for (tmp = skb->next; \
1200 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1201 skb = tmp, tmp = skb->next)
1202
1203 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1204 {
1205 return sk->sk_send_head;
1206 }
1207
1208 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1209 {
1210 sk->sk_send_head = skb->next;
1211 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
1212 sk->sk_send_head = NULL;
1213 }
1214
1215 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1216 {
1217 if (sk->sk_send_head == skb_unlinked)
1218 sk->sk_send_head = NULL;
1219 }
1220
1221 static inline void tcp_init_send_head(struct sock *sk)
1222 {
1223 sk->sk_send_head = NULL;
1224 }
1225
1226 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1227 {
1228 __skb_queue_tail(&sk->sk_write_queue, skb);
1229 }
1230
1231 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1232 {
1233 __tcp_add_write_queue_tail(sk, skb);
1234
1235 /* Queue it, remembering where we must start sending. */
1236 if (sk->sk_send_head == NULL) {
1237 sk->sk_send_head = skb;
1238
1239 if (tcp_sk(sk)->highest_sack == NULL)
1240 tcp_sk(sk)->highest_sack = skb;
1241 }
1242 }
1243
1244 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1245 {
1246 __skb_queue_head(&sk->sk_write_queue, skb);
1247 }
1248
1249 /* Insert buff after skb on the write queue of sk. */
1250 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1251 struct sk_buff *buff,
1252 struct sock *sk)
1253 {
1254 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1255 }
1256
1257 /* Insert skb between prev and next on the write queue of sk. */
1258 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1259 struct sk_buff *skb,
1260 struct sock *sk)
1261 {
1262 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
1263
1264 if (sk->sk_send_head == skb)
1265 sk->sk_send_head = new;
1266 }
1267
1268 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1269 {
1270 __skb_unlink(skb, &sk->sk_write_queue);
1271 }
1272
1273 static inline int tcp_skb_is_last(const struct sock *sk,
1274 const struct sk_buff *skb)
1275 {
1276 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1277 }
1278
1279 static inline int tcp_write_queue_empty(struct sock *sk)
1280 {
1281 return skb_queue_empty(&sk->sk_write_queue);
1282 }
1283
1284 /* Start sequence of the highest skb with SACKed bit, valid only if
1285 * sacked > 0 or when the caller has ensured validity by itself.
1286 */
1287 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1288 {
1289 if (!tp->sacked_out)
1290 return tp->snd_una;
1291
1292 if (tp->highest_sack == NULL)
1293 return tp->snd_nxt;
1294
1295 return TCP_SKB_CB(tp->highest_sack)->seq;
1296 }
1297
1298 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1299 {
1300 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1301 tcp_write_queue_next(sk, skb);
1302 }
1303
1304 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1305 {
1306 return tcp_sk(sk)->highest_sack;
1307 }
1308
1309 static inline void tcp_highest_sack_reset(struct sock *sk)
1310 {
1311 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1312 }
1313
1314 /* Called when old skb is about to be deleted (to be combined with new skb) */
1315 static inline void tcp_highest_sack_combine(struct sock *sk,
1316 struct sk_buff *old,
1317 struct sk_buff *new)
1318 {
1319 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1320 tcp_sk(sk)->highest_sack = new;
1321 }
1322
1323 /* /proc */
1324 enum tcp_seq_states {
1325 TCP_SEQ_STATE_LISTENING,
1326 TCP_SEQ_STATE_OPENREQ,
1327 TCP_SEQ_STATE_ESTABLISHED,
1328 TCP_SEQ_STATE_TIME_WAIT,
1329 };
1330
1331 struct tcp_seq_afinfo {
1332 char *name;
1333 sa_family_t family;
1334 struct file_operations seq_fops;
1335 struct seq_operations seq_ops;
1336 };
1337
1338 struct tcp_iter_state {
1339 struct seq_net_private p;
1340 sa_family_t family;
1341 enum tcp_seq_states state;
1342 struct sock *syn_wait_sk;
1343 int bucket, sbucket, num, uid;
1344 };
1345
1346 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1347 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1348
1349 extern struct request_sock_ops tcp_request_sock_ops;
1350 extern struct request_sock_ops tcp6_request_sock_ops;
1351
1352 extern int tcp_v4_destroy_sock(struct sock *sk);
1353
1354 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1355 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1356
1357 #ifdef CONFIG_PROC_FS
1358 extern int tcp4_proc_init(void);
1359 extern void tcp4_proc_exit(void);
1360 #endif
1361
1362 /* TCP af-specific functions */
1363 struct tcp_sock_af_ops {
1364 #ifdef CONFIG_TCP_MD5SIG
1365 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1366 struct sock *addr_sk);
1367 int (*calc_md5_hash) (char *location,
1368 struct tcp_md5sig_key *md5,
1369 struct sock *sk,
1370 struct dst_entry *dst,
1371 struct request_sock *req,
1372 struct tcphdr *th,
1373 int protocol,
1374 unsigned int len);
1375 int (*md5_add) (struct sock *sk,
1376 struct sock *addr_sk,
1377 u8 *newkey,
1378 u8 len);
1379 int (*md5_parse) (struct sock *sk,
1380 char __user *optval,
1381 int optlen);
1382 #endif
1383 };
1384
1385 struct tcp_request_sock_ops {
1386 #ifdef CONFIG_TCP_MD5SIG
1387 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1388 struct request_sock *req);
1389 #endif
1390 };
1391
1392 extern void tcp_v4_init(void);
1393 extern void tcp_init(void);
1394
1395 #endif /* _TCP_H */
Linux kernel - Deliverables
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