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[TCP]: Uninline tcp_set_state
[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
33 #include <net/inet_connection_sock.h>
34 #include <net/inet_timewait_sock.h>
35 #include <net/inet_hashtables.h>
36 #include <net/checksum.h>
37 #include <net/request_sock.h>
38 #include <net/sock.h>
39 #include <net/snmp.h>
40 #include <net/ip.h>
41 #include <net/tcp_states.h>
42 #include <net/inet_ecn.h>
43
44 #include <linux/seq_file.h>
45
46 extern struct inet_hashinfo tcp_hashinfo;
47
48 extern atomic_t tcp_orphan_count;
49 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
50
51 #define MAX_TCP_HEADER (128 + MAX_HEADER)
52
53 /*
54 * Never offer a window over 32767 without using window scaling. Some
55 * poor stacks do signed 16bit maths!
56 */
57 #define MAX_TCP_WINDOW 32767U
58
59 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
60 #define TCP_MIN_MSS 88U
61
62 /* Minimal RCV_MSS. */
63 #define TCP_MIN_RCVMSS 536U
64
65 /* The least MTU to use for probing */
66 #define TCP_BASE_MSS 512
67
68 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
69 #define TCP_FASTRETRANS_THRESH 3
70
71 /* Maximal reordering. */
72 #define TCP_MAX_REORDERING 127
73
74 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
75 #define TCP_MAX_QUICKACKS 16U
76
77 /* urg_data states */
78 #define TCP_URG_VALID 0x0100
79 #define TCP_URG_NOTYET 0x0200
80 #define TCP_URG_READ 0x0400
81
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.
87 */
88
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.
94 */
95
96 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
97 * connection: ~180sec is RFC minimum */
98
99 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
100 * connection: ~180sec is RFC minimum */
101
102
103 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
104 * socket. 7 is ~50sec-16min.
105 */
106
107
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
114 * TIME-WAIT timer.
115 */
116
117 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
118 #if HZ >= 100
119 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
120 #define TCP_ATO_MIN ((unsigned)(HZ/25))
121 #else
122 #define TCP_DELACK_MIN 4U
123 #define TCP_ATO_MIN 4U
124 #endif
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 */
128
129 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
130 * for local resources.
131 */
132
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)
136
137 #define MAX_TCP_KEEPIDLE 32767
138 #define MAX_TCP_KEEPINTVL 32767
139 #define MAX_TCP_KEEPCNT 127
140 #define MAX_TCP_SYNCNT 127
141
142 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
143
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.
150 */
151 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
152 * timestamps. It must be less than
153 * minimal timewait lifetime.
154 */
155 /*
156 * TCP option
157 */
158
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) */
167
168 /*
169 * TCP option lengths
170 */
171
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
177
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
187 /* Flags in tp->nonagle */
188 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
189 #define TCP_NAGLE_CORK 2 /* Socket is corked */
190 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
191
192 extern struct inet_timewait_death_row tcp_death_row;
193
194 /* sysctl variables for tcp */
195 extern int sysctl_tcp_timestamps;
196 extern int sysctl_tcp_window_scaling;
197 extern int sysctl_tcp_sack;
198 extern int sysctl_tcp_fin_timeout;
199 extern int sysctl_tcp_keepalive_time;
200 extern int sysctl_tcp_keepalive_probes;
201 extern int sysctl_tcp_keepalive_intvl;
202 extern int sysctl_tcp_syn_retries;
203 extern int sysctl_tcp_synack_retries;
204 extern int sysctl_tcp_retries1;
205 extern int sysctl_tcp_retries2;
206 extern int sysctl_tcp_orphan_retries;
207 extern int sysctl_tcp_syncookies;
208 extern int sysctl_tcp_retrans_collapse;
209 extern int sysctl_tcp_stdurg;
210 extern int sysctl_tcp_rfc1337;
211 extern int sysctl_tcp_abort_on_overflow;
212 extern int sysctl_tcp_max_orphans;
213 extern int sysctl_tcp_fack;
214 extern int sysctl_tcp_reordering;
215 extern int sysctl_tcp_ecn;
216 extern int sysctl_tcp_dsack;
217 extern int sysctl_tcp_mem[3];
218 extern int sysctl_tcp_wmem[3];
219 extern int sysctl_tcp_rmem[3];
220 extern int sysctl_tcp_app_win;
221 extern int sysctl_tcp_adv_win_scale;
222 extern int sysctl_tcp_tw_reuse;
223 extern int sysctl_tcp_frto;
224 extern int sysctl_tcp_frto_response;
225 extern int sysctl_tcp_low_latency;
226 extern int sysctl_tcp_dma_copybreak;
227 extern int sysctl_tcp_nometrics_save;
228 extern int sysctl_tcp_moderate_rcvbuf;
229 extern int sysctl_tcp_tso_win_divisor;
230 extern int sysctl_tcp_abc;
231 extern int sysctl_tcp_mtu_probing;
232 extern int sysctl_tcp_base_mss;
233 extern int sysctl_tcp_workaround_signed_windows;
234 extern int sysctl_tcp_slow_start_after_idle;
235 extern int sysctl_tcp_max_ssthresh;
236
237 extern atomic_t tcp_memory_allocated;
238 extern atomic_t tcp_sockets_allocated;
239 extern int tcp_memory_pressure;
240
241 /*
242 * The next routines deal with comparing 32 bit unsigned ints
243 * and worry about wraparound (automatic with unsigned arithmetic).
244 */
245
246 static inline int before(__u32 seq1, __u32 seq2)
247 {
248 return (__s32)(seq1-seq2) < 0;
249 }
250 #define after(seq2, seq1) before(seq1, seq2)
251
252 /* is s2<=s1<=s3 ? */
253 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
254 {
255 return seq3 - seq2 >= seq1 - seq2;
256 }
257
258 static inline int tcp_too_many_orphans(struct sock *sk, int num)
259 {
260 return (num > sysctl_tcp_max_orphans) ||
261 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
262 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
263 }
264
265 extern struct proto tcp_prot;
266
267 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
268 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
269 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
270 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
271 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
272 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
273 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
274
275 extern void tcp_v4_err(struct sk_buff *skb, u32);
276
277 extern void tcp_shutdown (struct sock *sk, int how);
278
279 extern int tcp_v4_rcv(struct sk_buff *skb);
280
281 extern int tcp_v4_remember_stamp(struct sock *sk);
282
283 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
284
285 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
286 struct msghdr *msg, size_t size);
287 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
288
289 extern int tcp_ioctl(struct sock *sk,
290 int cmd,
291 unsigned long arg);
292
293 extern int tcp_rcv_state_process(struct sock *sk,
294 struct sk_buff *skb,
295 struct tcphdr *th,
296 unsigned len);
297
298 extern int tcp_rcv_established(struct sock *sk,
299 struct sk_buff *skb,
300 struct tcphdr *th,
301 unsigned len);
302
303 extern void tcp_rcv_space_adjust(struct sock *sk);
304
305 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
306
307 extern int tcp_twsk_unique(struct sock *sk,
308 struct sock *sktw, void *twp);
309
310 extern void tcp_twsk_destructor(struct sock *sk);
311
312 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
313 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
314
315 static inline void tcp_dec_quickack_mode(struct sock *sk,
316 const unsigned int pkts)
317 {
318 struct inet_connection_sock *icsk = inet_csk(sk);
319
320 if (icsk->icsk_ack.quick) {
321 if (pkts >= icsk->icsk_ack.quick) {
322 icsk->icsk_ack.quick = 0;
323 /* Leaving quickack mode we deflate ATO. */
324 icsk->icsk_ack.ato = TCP_ATO_MIN;
325 } else
326 icsk->icsk_ack.quick -= pkts;
327 }
328 }
329
330 extern void tcp_enter_quickack_mode(struct sock *sk);
331
332 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
333 {
334 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
335 }
336
337 #define TCP_ECN_OK 1
338 #define TCP_ECN_QUEUE_CWR 2
339 #define TCP_ECN_DEMAND_CWR 4
340
341 static __inline__ void
342 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
343 {
344 if (sysctl_tcp_ecn && th->ece && th->cwr)
345 inet_rsk(req)->ecn_ok = 1;
346 }
347
348 enum tcp_tw_status
349 {
350 TCP_TW_SUCCESS = 0,
351 TCP_TW_RST = 1,
352 TCP_TW_ACK = 2,
353 TCP_TW_SYN = 3
354 };
355
356
357 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
358 struct sk_buff *skb,
359 const struct tcphdr *th);
360
361 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
362 struct request_sock *req,
363 struct request_sock **prev);
364 extern int tcp_child_process(struct sock *parent,
365 struct sock *child,
366 struct sk_buff *skb);
367 extern int tcp_use_frto(struct sock *sk);
368 extern void tcp_enter_frto(struct sock *sk);
369 extern void tcp_enter_loss(struct sock *sk, int how);
370 extern void tcp_clear_retrans(struct tcp_sock *tp);
371 extern void tcp_update_metrics(struct sock *sk);
372
373 extern void tcp_close(struct sock *sk,
374 long timeout);
375 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
376
377 extern int tcp_getsockopt(struct sock *sk, int level,
378 int optname,
379 char __user *optval,
380 int __user *optlen);
381 extern int tcp_setsockopt(struct sock *sk, int level,
382 int optname, char __user *optval,
383 int optlen);
384 extern int compat_tcp_getsockopt(struct sock *sk,
385 int level, int optname,
386 char __user *optval, int __user *optlen);
387 extern int compat_tcp_setsockopt(struct sock *sk,
388 int level, int optname,
389 char __user *optval, int optlen);
390 extern void tcp_set_keepalive(struct sock *sk, int val);
391 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
392 struct msghdr *msg,
393 size_t len, int nonblock,
394 int flags, int *addr_len);
395
396 extern void tcp_parse_options(struct sk_buff *skb,
397 struct tcp_options_received *opt_rx,
398 int estab);
399
400 /*
401 * TCP v4 functions exported for the inet6 API
402 */
403
404 extern void tcp_v4_send_check(struct sock *sk, int len,
405 struct sk_buff *skb);
406
407 extern int tcp_v4_conn_request(struct sock *sk,
408 struct sk_buff *skb);
409
410 extern struct sock * tcp_create_openreq_child(struct sock *sk,
411 struct request_sock *req,
412 struct sk_buff *skb);
413
414 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
415 struct sk_buff *skb,
416 struct request_sock *req,
417 struct dst_entry *dst);
418
419 extern int tcp_v4_do_rcv(struct sock *sk,
420 struct sk_buff *skb);
421
422 extern int tcp_v4_connect(struct sock *sk,
423 struct sockaddr *uaddr,
424 int addr_len);
425
426 extern int tcp_connect(struct sock *sk);
427
428 extern struct sk_buff * tcp_make_synack(struct sock *sk,
429 struct dst_entry *dst,
430 struct request_sock *req);
431
432 extern int tcp_disconnect(struct sock *sk, int flags);
433
434 extern void tcp_unhash(struct sock *sk);
435
436 /* From syncookies.c */
437 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
438 struct ip_options *opt);
439 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
440 __u16 *mss);
441
442 /* tcp_output.c */
443
444 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
445 int nonagle);
446 extern int tcp_may_send_now(struct sock *sk);
447 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
448 extern void tcp_xmit_retransmit_queue(struct sock *);
449 extern void tcp_simple_retransmit(struct sock *);
450 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
451 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
452
453 extern void tcp_send_probe0(struct sock *);
454 extern void tcp_send_partial(struct sock *);
455 extern int tcp_write_wakeup(struct sock *);
456 extern void tcp_send_fin(struct sock *sk);
457 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
458 extern int tcp_send_synack(struct sock *);
459 extern void tcp_push_one(struct sock *, unsigned int mss_now);
460 extern void tcp_send_ack(struct sock *sk);
461 extern void tcp_send_delayed_ack(struct sock *sk);
462
463 /* tcp_input.c */
464 extern void tcp_cwnd_application_limited(struct sock *sk);
465
466 /* tcp_timer.c */
467 extern void tcp_init_xmit_timers(struct sock *);
468 static inline void tcp_clear_xmit_timers(struct sock *sk)
469 {
470 inet_csk_clear_xmit_timers(sk);
471 }
472
473 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
474 extern unsigned int tcp_current_mss(struct sock *sk, int large);
475
476 /* tcp.c */
477 extern void tcp_get_info(struct sock *, struct tcp_info *);
478
479 /* Read 'sendfile()'-style from a TCP socket */
480 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
481 unsigned int, size_t);
482 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
483 sk_read_actor_t recv_actor);
484
485 extern void tcp_initialize_rcv_mss(struct sock *sk);
486
487 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
488 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
489 extern void tcp_mtup_init(struct sock *sk);
490
491 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
492 {
493 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
494 ntohl(TCP_FLAG_ACK) |
495 snd_wnd);
496 }
497
498 static inline void tcp_fast_path_on(struct tcp_sock *tp)
499 {
500 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
501 }
502
503 static inline void tcp_fast_path_check(struct sock *sk)
504 {
505 struct tcp_sock *tp = tcp_sk(sk);
506
507 if (skb_queue_empty(&tp->out_of_order_queue) &&
508 tp->rcv_wnd &&
509 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
510 !tp->urg_data)
511 tcp_fast_path_on(tp);
512 }
513
514 /* Compute the actual receive window we are currently advertising.
515 * Rcv_nxt can be after the window if our peer push more data
516 * than the offered window.
517 */
518 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
519 {
520 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
521
522 if (win < 0)
523 win = 0;
524 return (u32) win;
525 }
526
527 /* Choose a new window, without checks for shrinking, and without
528 * scaling applied to the result. The caller does these things
529 * if necessary. This is a "raw" window selection.
530 */
531 extern u32 __tcp_select_window(struct sock *sk);
532
533 /* TCP timestamps are only 32-bits, this causes a slight
534 * complication on 64-bit systems since we store a snapshot
535 * of jiffies in the buffer control blocks below. We decided
536 * to use only the low 32-bits of jiffies and hide the ugly
537 * casts with the following macro.
538 */
539 #define tcp_time_stamp ((__u32)(jiffies))
540
541 /* This is what the send packet queuing engine uses to pass
542 * TCP per-packet control information to the transmission
543 * code. We also store the host-order sequence numbers in
544 * here too. This is 36 bytes on 32-bit architectures,
545 * 40 bytes on 64-bit machines, if this grows please adjust
546 * skbuff.h:skbuff->cb[xxx] size appropriately.
547 */
548 struct tcp_skb_cb {
549 union {
550 struct inet_skb_parm h4;
551 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
552 struct inet6_skb_parm h6;
553 #endif
554 } header; /* For incoming frames */
555 __u32 seq; /* Starting sequence number */
556 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
557 __u32 when; /* used to compute rtt's */
558 __u8 flags; /* TCP header flags. */
559
560 /* NOTE: These must match up to the flags byte in a
561 * real TCP header.
562 */
563 #define TCPCB_FLAG_FIN 0x01
564 #define TCPCB_FLAG_SYN 0x02
565 #define TCPCB_FLAG_RST 0x04
566 #define TCPCB_FLAG_PSH 0x08
567 #define TCPCB_FLAG_ACK 0x10
568 #define TCPCB_FLAG_URG 0x20
569 #define TCPCB_FLAG_ECE 0x40
570 #define TCPCB_FLAG_CWR 0x80
571
572 __u8 sacked; /* State flags for SACK/FACK. */
573 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
574 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
575 #define TCPCB_LOST 0x04 /* SKB is lost */
576 #define TCPCB_TAGBITS 0x07 /* All tag bits */
577
578 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
579 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
580
581 __u16 urg_ptr; /* Valid w/URG flags is set. */
582 __u32 ack_seq; /* Sequence number ACK'd */
583 };
584
585 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
586
587 /* Due to TSO, an SKB can be composed of multiple actual
588 * packets. To keep these tracked properly, we use this.
589 */
590 static inline int tcp_skb_pcount(const struct sk_buff *skb)
591 {
592 return skb_shinfo(skb)->gso_segs;
593 }
594
595 /* This is valid iff tcp_skb_pcount() > 1. */
596 static inline int tcp_skb_mss(const struct sk_buff *skb)
597 {
598 return skb_shinfo(skb)->gso_size;
599 }
600
601 static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
602 {
603 if (*count) {
604 *count -= decr;
605 if ((int)*count < 0)
606 *count = 0;
607 }
608 }
609
610 static inline void tcp_dec_pcount_approx(__u32 *count,
611 const struct sk_buff *skb)
612 {
613 tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
614 }
615
616 /* Events passed to congestion control interface */
617 enum tcp_ca_event {
618 CA_EVENT_TX_START, /* first transmit when no packets in flight */
619 CA_EVENT_CWND_RESTART, /* congestion window restart */
620 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
621 CA_EVENT_FRTO, /* fast recovery timeout */
622 CA_EVENT_LOSS, /* loss timeout */
623 CA_EVENT_FAST_ACK, /* in sequence ack */
624 CA_EVENT_SLOW_ACK, /* other ack */
625 };
626
627 /*
628 * Interface for adding new TCP congestion control handlers
629 */
630 #define TCP_CA_NAME_MAX 16
631 #define TCP_CA_MAX 128
632 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
633
634 #define TCP_CONG_NON_RESTRICTED 0x1
635 #define TCP_CONG_RTT_STAMP 0x2
636
637 struct tcp_congestion_ops {
638 struct list_head list;
639 unsigned long flags;
640
641 /* initialize private data (optional) */
642 void (*init)(struct sock *sk);
643 /* cleanup private data (optional) */
644 void (*release)(struct sock *sk);
645
646 /* return slow start threshold (required) */
647 u32 (*ssthresh)(struct sock *sk);
648 /* lower bound for congestion window (optional) */
649 u32 (*min_cwnd)(const struct sock *sk);
650 /* do new cwnd calculation (required) */
651 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
652 /* call before changing ca_state (optional) */
653 void (*set_state)(struct sock *sk, u8 new_state);
654 /* call when cwnd event occurs (optional) */
655 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
656 /* new value of cwnd after loss (optional) */
657 u32 (*undo_cwnd)(struct sock *sk);
658 /* hook for packet ack accounting (optional) */
659 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
660 /* get info for inet_diag (optional) */
661 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
662
663 char name[TCP_CA_NAME_MAX];
664 struct module *owner;
665 };
666
667 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
668 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
669
670 extern void tcp_init_congestion_control(struct sock *sk);
671 extern void tcp_cleanup_congestion_control(struct sock *sk);
672 extern int tcp_set_default_congestion_control(const char *name);
673 extern void tcp_get_default_congestion_control(char *name);
674 extern void tcp_get_available_congestion_control(char *buf, size_t len);
675 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
676 extern int tcp_set_allowed_congestion_control(char *allowed);
677 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
678 extern void tcp_slow_start(struct tcp_sock *tp);
679
680 extern struct tcp_congestion_ops tcp_init_congestion_ops;
681 extern u32 tcp_reno_ssthresh(struct sock *sk);
682 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
683 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
684 extern struct tcp_congestion_ops tcp_reno;
685
686 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
687 {
688 struct inet_connection_sock *icsk = inet_csk(sk);
689
690 if (icsk->icsk_ca_ops->set_state)
691 icsk->icsk_ca_ops->set_state(sk, ca_state);
692 icsk->icsk_ca_state = ca_state;
693 }
694
695 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
696 {
697 const struct inet_connection_sock *icsk = inet_csk(sk);
698
699 if (icsk->icsk_ca_ops->cwnd_event)
700 icsk->icsk_ca_ops->cwnd_event(sk, event);
701 }
702
703 /* These functions determine how the current flow behaves in respect of SACK
704 * handling. SACK is negotiated with the peer, and therefore it can vary
705 * between different flows.
706 *
707 * tcp_is_sack - SACK enabled
708 * tcp_is_reno - No SACK
709 * tcp_is_fack - FACK enabled, implies SACK enabled
710 */
711 static inline int tcp_is_sack(const struct tcp_sock *tp)
712 {
713 return tp->rx_opt.sack_ok;
714 }
715
716 static inline int tcp_is_reno(const struct tcp_sock *tp)
717 {
718 return !tcp_is_sack(tp);
719 }
720
721 static inline int tcp_is_fack(const struct tcp_sock *tp)
722 {
723 return tp->rx_opt.sack_ok & 2;
724 }
725
726 static inline void tcp_enable_fack(struct tcp_sock *tp)
727 {
728 tp->rx_opt.sack_ok |= 2;
729 }
730
731 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
732 {
733 return tp->sacked_out + tp->lost_out;
734 }
735
736 /* This determines how many packets are "in the network" to the best
737 * of our knowledge. In many cases it is conservative, but where
738 * detailed information is available from the receiver (via SACK
739 * blocks etc.) we can make more aggressive calculations.
740 *
741 * Use this for decisions involving congestion control, use just
742 * tp->packets_out to determine if the send queue is empty or not.
743 *
744 * Read this equation as:
745 *
746 * "Packets sent once on transmission queue" MINUS
747 * "Packets left network, but not honestly ACKed yet" PLUS
748 * "Packets fast retransmitted"
749 */
750 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
751 {
752 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
753 }
754
755 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
756 * The exception is rate halving phase, when cwnd is decreasing towards
757 * ssthresh.
758 */
759 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
760 {
761 const struct tcp_sock *tp = tcp_sk(sk);
762 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
763 return tp->snd_ssthresh;
764 else
765 return max(tp->snd_ssthresh,
766 ((tp->snd_cwnd >> 1) +
767 (tp->snd_cwnd >> 2)));
768 }
769
770 /* Use define here intentionally to get WARN_ON location shown at the caller */
771 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
772
773 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
774 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
775
776 /* Slow start with delack produces 3 packets of burst, so that
777 * it is safe "de facto".
778 */
779 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
780 {
781 return 3;
782 }
783
784 /* Returns end sequence number of the receiver's advertised window */
785 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
786 {
787 return tp->snd_una + tp->snd_wnd;
788 }
789
790 /* RFC2861 Check whether we are limited by application or congestion window
791 * This is the inverse of cwnd check in tcp_tso_should_defer
792 */
793 static inline int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight)
794 {
795 const struct tcp_sock *tp = tcp_sk(sk);
796 u32 left;
797
798 if (in_flight >= tp->snd_cwnd)
799 return 1;
800
801 if (!sk_can_gso(sk))
802 return 0;
803
804 left = tp->snd_cwnd - in_flight;
805 if (sysctl_tcp_tso_win_divisor)
806 return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd;
807 else
808 return left <= tcp_max_burst(tp);
809 }
810
811 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
812 const struct sk_buff *skb)
813 {
814 if (skb->len < mss)
815 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
816 }
817
818 static inline void tcp_check_probe_timer(struct sock *sk)
819 {
820 struct tcp_sock *tp = tcp_sk(sk);
821 const struct inet_connection_sock *icsk = inet_csk(sk);
822
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);
826 }
827
828 static inline void tcp_push_pending_frames(struct sock *sk)
829 {
830 struct tcp_sock *tp = tcp_sk(sk);
831
832 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
833 }
834
835 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
836 {
837 tp->snd_wl1 = seq;
838 }
839
840 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
841 {
842 tp->snd_wl1 = seq;
843 }
844
845 /*
846 * Calculate(/check) TCP checksum
847 */
848 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
849 __be32 daddr, __wsum base)
850 {
851 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
852 }
853
854 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
855 {
856 return __skb_checksum_complete(skb);
857 }
858
859 static inline int tcp_checksum_complete(struct sk_buff *skb)
860 {
861 return !skb_csum_unnecessary(skb) &&
862 __tcp_checksum_complete(skb);
863 }
864
865 /* Prequeue for VJ style copy to user, combined with checksumming. */
866
867 static inline void tcp_prequeue_init(struct tcp_sock *tp)
868 {
869 tp->ucopy.task = NULL;
870 tp->ucopy.len = 0;
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;
878 #endif
879 }
880
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
886 *
887 * NOTE: is this not too big to inline?
888 */
889 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
890 {
891 struct tcp_sock *tp = tcp_sk(sk);
892
893 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
894 __skb_queue_tail(&tp->ucopy.prequeue, skb);
895 tp->ucopy.memory += skb->truesize;
896 if (tp->ucopy.memory > sk->sk_rcvbuf) {
897 struct sk_buff *skb1;
898
899 BUG_ON(sock_owned_by_user(sk));
900
901 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
902 sk->sk_backlog_rcv(sk, skb1);
903 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
904 }
905
906 tp->ucopy.memory = 0;
907 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
908 wake_up_interruptible(sk->sk_sleep);
909 if (!inet_csk_ack_scheduled(sk))
910 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
911 (3 * TCP_RTO_MIN) / 4,
912 TCP_RTO_MAX);
913 }
914 return 1;
915 }
916 return 0;
917 }
918
919
920 #undef STATE_TRACE
921
922 #ifdef STATE_TRACE
923 static const char *statename[]={
924 "Unused","Established","Syn Sent","Syn Recv",
925 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
926 "Close Wait","Last ACK","Listen","Closing"
927 };
928 #endif
929 extern void tcp_set_state(struct sock *sk, int state);
930
931 extern void tcp_done(struct sock *sk);
932
933 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
934 {
935 rx_opt->dsack = 0;
936 rx_opt->eff_sacks = 0;
937 rx_opt->num_sacks = 0;
938 }
939
940 /* Determine a window scaling and initial window to offer. */
941 extern void tcp_select_initial_window(int __space, __u32 mss,
942 __u32 *rcv_wnd, __u32 *window_clamp,
943 int wscale_ok, __u8 *rcv_wscale);
944
945 static inline int tcp_win_from_space(int space)
946 {
947 return sysctl_tcp_adv_win_scale<=0 ?
948 (space>>(-sysctl_tcp_adv_win_scale)) :
949 space - (space>>sysctl_tcp_adv_win_scale);
950 }
951
952 /* Note: caller must be prepared to deal with negative returns */
953 static inline int tcp_space(const struct sock *sk)
954 {
955 return tcp_win_from_space(sk->sk_rcvbuf -
956 atomic_read(&sk->sk_rmem_alloc));
957 }
958
959 static inline int tcp_full_space(const struct sock *sk)
960 {
961 return tcp_win_from_space(sk->sk_rcvbuf);
962 }
963
964 static inline void tcp_openreq_init(struct request_sock *req,
965 struct tcp_options_received *rx_opt,
966 struct sk_buff *skb)
967 {
968 struct inet_request_sock *ireq = inet_rsk(req);
969
970 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
971 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
972 req->mss = rx_opt->mss_clamp;
973 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
974 ireq->tstamp_ok = rx_opt->tstamp_ok;
975 ireq->sack_ok = rx_opt->sack_ok;
976 ireq->snd_wscale = rx_opt->snd_wscale;
977 ireq->wscale_ok = rx_opt->wscale_ok;
978 ireq->acked = 0;
979 ireq->ecn_ok = 0;
980 ireq->rmt_port = tcp_hdr(skb)->source;
981 }
982
983 extern void tcp_enter_memory_pressure(void);
984
985 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
986 {
987 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
988 }
989
990 static inline int keepalive_time_when(const struct tcp_sock *tp)
991 {
992 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
993 }
994
995 static inline int tcp_fin_time(const struct sock *sk)
996 {
997 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
998 const int rto = inet_csk(sk)->icsk_rto;
999
1000 if (fin_timeout < (rto << 2) - (rto >> 1))
1001 fin_timeout = (rto << 2) - (rto >> 1);
1002
1003 return fin_timeout;
1004 }
1005
1006 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1007 {
1008 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1009 return 0;
1010 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1011 return 0;
1012
1013 /* RST segments are not recommended to carry timestamp,
1014 and, if they do, it is recommended to ignore PAWS because
1015 "their cleanup function should take precedence over timestamps."
1016 Certainly, it is mistake. It is necessary to understand the reasons
1017 of this constraint to relax it: if peer reboots, clock may go
1018 out-of-sync and half-open connections will not be reset.
1019 Actually, the problem would be not existing if all
1020 the implementations followed draft about maintaining clock
1021 via reboots. Linux-2.2 DOES NOT!
1022
1023 However, we can relax time bounds for RST segments to MSL.
1024 */
1025 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1026 return 0;
1027 return 1;
1028 }
1029
1030 #define TCP_CHECK_TIMER(sk) do { } while (0)
1031
1032 static inline void tcp_mib_init(void)
1033 {
1034 /* See RFC 2012 */
1035 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1036 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1037 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1038 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
1039 }
1040
1041 /* from STCP */
1042 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1043 {
1044 tp->lost_skb_hint = NULL;
1045 tp->scoreboard_skb_hint = NULL;
1046 tp->retransmit_skb_hint = NULL;
1047 tp->forward_skb_hint = NULL;
1048 }
1049
1050 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1051 {
1052 tcp_clear_retrans_hints_partial(tp);
1053 }
1054
1055 /* MD5 Signature */
1056 struct crypto_hash;
1057
1058 /* - key database */
1059 struct tcp_md5sig_key {
1060 u8 *key;
1061 u8 keylen;
1062 };
1063
1064 struct tcp4_md5sig_key {
1065 struct tcp_md5sig_key base;
1066 __be32 addr;
1067 };
1068
1069 struct tcp6_md5sig_key {
1070 struct tcp_md5sig_key base;
1071 #if 0
1072 u32 scope_id; /* XXX */
1073 #endif
1074 struct in6_addr addr;
1075 };
1076
1077 /* - sock block */
1078 struct tcp_md5sig_info {
1079 struct tcp4_md5sig_key *keys4;
1080 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1081 struct tcp6_md5sig_key *keys6;
1082 u32 entries6;
1083 u32 alloced6;
1084 #endif
1085 u32 entries4;
1086 u32 alloced4;
1087 };
1088
1089 /* - pseudo header */
1090 struct tcp4_pseudohdr {
1091 __be32 saddr;
1092 __be32 daddr;
1093 __u8 pad;
1094 __u8 protocol;
1095 __be16 len;
1096 };
1097
1098 struct tcp6_pseudohdr {
1099 struct in6_addr saddr;
1100 struct in6_addr daddr;
1101 __be32 len;
1102 __be32 protocol; /* including padding */
1103 };
1104
1105 union tcp_md5sum_block {
1106 struct tcp4_pseudohdr ip4;
1107 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1108 struct tcp6_pseudohdr ip6;
1109 #endif
1110 };
1111
1112 /* - pool: digest algorithm, hash description and scratch buffer */
1113 struct tcp_md5sig_pool {
1114 struct hash_desc md5_desc;
1115 union tcp_md5sum_block md5_blk;
1116 };
1117
1118 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1119
1120 /* - functions */
1121 extern int tcp_v4_calc_md5_hash(char *md5_hash,
1122 struct tcp_md5sig_key *key,
1123 struct sock *sk,
1124 struct dst_entry *dst,
1125 struct request_sock *req,
1126 struct tcphdr *th,
1127 int protocol,
1128 unsigned int tcplen);
1129 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1130 struct sock *addr_sk);
1131
1132 extern int tcp_v4_md5_do_add(struct sock *sk,
1133 __be32 addr,
1134 u8 *newkey,
1135 u8 newkeylen);
1136
1137 extern int tcp_v4_md5_do_del(struct sock *sk,
1138 __be32 addr);
1139
1140 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1141 extern void tcp_free_md5sig_pool(void);
1142
1143 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1144 extern void __tcp_put_md5sig_pool(void);
1145
1146 static inline
1147 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1148 {
1149 int cpu = get_cpu();
1150 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1151 if (!ret)
1152 put_cpu();
1153 return ret;
1154 }
1155
1156 static inline void tcp_put_md5sig_pool(void)
1157 {
1158 __tcp_put_md5sig_pool();
1159 put_cpu();
1160 }
1161
1162 /* write queue abstraction */
1163 static inline void tcp_write_queue_purge(struct sock *sk)
1164 {
1165 struct sk_buff *skb;
1166
1167 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1168 sk_wmem_free_skb(sk, skb);
1169 sk_mem_reclaim(sk);
1170 }
1171
1172 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1173 {
1174 struct sk_buff *skb = sk->sk_write_queue.next;
1175 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1176 return NULL;
1177 return skb;
1178 }
1179
1180 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1181 {
1182 struct sk_buff *skb = sk->sk_write_queue.prev;
1183 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1184 return NULL;
1185 return skb;
1186 }
1187
1188 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1189 {
1190 return skb->next;
1191 }
1192
1193 #define tcp_for_write_queue(skb, sk) \
1194 for (skb = (sk)->sk_write_queue.next; \
1195 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1196 skb = skb->next)
1197
1198 #define tcp_for_write_queue_from(skb, sk) \
1199 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\
1200 skb = skb->next)
1201
1202 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1203 for (tmp = skb->next; \
1204 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1205 skb = tmp, tmp = skb->next)
1206
1207 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1208 {
1209 return sk->sk_send_head;
1210 }
1211
1212 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1213 {
1214 sk->sk_send_head = skb->next;
1215 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
1216 sk->sk_send_head = NULL;
1217 }
1218
1219 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1220 {
1221 if (sk->sk_send_head == skb_unlinked)
1222 sk->sk_send_head = NULL;
1223 }
1224
1225 static inline void tcp_init_send_head(struct sock *sk)
1226 {
1227 sk->sk_send_head = NULL;
1228 }
1229
1230 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1231 {
1232 __skb_queue_tail(&sk->sk_write_queue, skb);
1233 }
1234
1235 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1236 {
1237 __tcp_add_write_queue_tail(sk, skb);
1238
1239 /* Queue it, remembering where we must start sending. */
1240 if (sk->sk_send_head == NULL) {
1241 sk->sk_send_head = skb;
1242
1243 if (tcp_sk(sk)->highest_sack == NULL)
1244 tcp_sk(sk)->highest_sack = skb;
1245 }
1246 }
1247
1248 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1249 {
1250 __skb_queue_head(&sk->sk_write_queue, skb);
1251 }
1252
1253 /* Insert buff after skb on the write queue of sk. */
1254 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1255 struct sk_buff *buff,
1256 struct sock *sk)
1257 {
1258 __skb_append(skb, buff, &sk->sk_write_queue);
1259 }
1260
1261 /* Insert skb between prev and next on the write queue of sk. */
1262 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1263 struct sk_buff *skb,
1264 struct sock *sk)
1265 {
1266 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
1267
1268 if (sk->sk_send_head == skb)
1269 sk->sk_send_head = new;
1270 }
1271
1272 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1273 {
1274 __skb_unlink(skb, &sk->sk_write_queue);
1275 }
1276
1277 static inline int tcp_skb_is_last(const struct sock *sk,
1278 const struct sk_buff *skb)
1279 {
1280 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1281 }
1282
1283 static inline int tcp_write_queue_empty(struct sock *sk)
1284 {
1285 return skb_queue_empty(&sk->sk_write_queue);
1286 }
1287
1288 /* Start sequence of the highest skb with SACKed bit, valid only if
1289 * sacked > 0 or when the caller has ensured validity by itself.
1290 */
1291 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1292 {
1293 if (!tp->sacked_out)
1294 return tp->snd_una;
1295
1296 if (tp->highest_sack == NULL)
1297 return tp->snd_nxt;
1298
1299 return TCP_SKB_CB(tp->highest_sack)->seq;
1300 }
1301
1302 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1303 {
1304 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1305 tcp_write_queue_next(sk, skb);
1306 }
1307
1308 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1309 {
1310 return tcp_sk(sk)->highest_sack;
1311 }
1312
1313 static inline void tcp_highest_sack_reset(struct sock *sk)
1314 {
1315 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1316 }
1317
1318 /* Called when old skb is about to be deleted (to be combined with new skb) */
1319 static inline void tcp_highest_sack_combine(struct sock *sk,
1320 struct sk_buff *old,
1321 struct sk_buff *new)
1322 {
1323 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1324 tcp_sk(sk)->highest_sack = new;
1325 }
1326
1327 /* /proc */
1328 enum tcp_seq_states {
1329 TCP_SEQ_STATE_LISTENING,
1330 TCP_SEQ_STATE_OPENREQ,
1331 TCP_SEQ_STATE_ESTABLISHED,
1332 TCP_SEQ_STATE_TIME_WAIT,
1333 };
1334
1335 struct tcp_seq_afinfo {
1336 struct module *owner;
1337 char *name;
1338 sa_family_t family;
1339 int (*seq_show) (struct seq_file *m, void *v);
1340 struct file_operations *seq_fops;
1341 };
1342
1343 struct tcp_iter_state {
1344 sa_family_t family;
1345 enum tcp_seq_states state;
1346 struct sock *syn_wait_sk;
1347 int bucket, sbucket, num, uid;
1348 struct seq_operations seq_ops;
1349 };
1350
1351 extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo);
1352 extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo);
1353
1354 extern struct request_sock_ops tcp_request_sock_ops;
1355
1356 extern int tcp_v4_destroy_sock(struct sock *sk);
1357
1358 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1359 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1360
1361 #ifdef CONFIG_PROC_FS
1362 extern int tcp4_proc_init(void);
1363 extern void tcp4_proc_exit(void);
1364 #endif
1365
1366 /* TCP af-specific functions */
1367 struct tcp_sock_af_ops {
1368 #ifdef CONFIG_TCP_MD5SIG
1369 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1370 struct sock *addr_sk);
1371 int (*calc_md5_hash) (char *location,
1372 struct tcp_md5sig_key *md5,
1373 struct sock *sk,
1374 struct dst_entry *dst,
1375 struct request_sock *req,
1376 struct tcphdr *th,
1377 int protocol,
1378 unsigned int len);
1379 int (*md5_add) (struct sock *sk,
1380 struct sock *addr_sk,
1381 u8 *newkey,
1382 u8 len);
1383 int (*md5_parse) (struct sock *sk,
1384 char __user *optval,
1385 int optlen);
1386 #endif
1387 };
1388
1389 struct tcp_request_sock_ops {
1390 #ifdef CONFIG_TCP_MD5SIG
1391 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1392 struct request_sock *req);
1393 #endif
1394 };
1395
1396 extern void tcp_v4_init(struct net_proto_family *ops);
1397 extern void tcp_init(void);
1398
1399 #endif /* _TCP_H */
Linux kernel - Deliverables
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