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Merge branch 'release' of git://lm-sensors.org/kernel/mhoffman/hwmon-2.6
[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
43 #include <linux/seq_file.h>
44
45 extern struct inet_hashinfo tcp_hashinfo;
46
47 extern atomic_t tcp_orphan_count;
48 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
49
50 #define MAX_TCP_HEADER (128 + MAX_HEADER)
51
52 /*
53 * Never offer a window over 32767 without using window scaling. Some
54 * poor stacks do signed 16bit maths!
55 */
56 #define MAX_TCP_WINDOW 32767U
57
58 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
59 #define TCP_MIN_MSS 88U
60
61 /* Minimal RCV_MSS. */
62 #define TCP_MIN_RCVMSS 536U
63
64 /* The least MTU to use for probing */
65 #define TCP_BASE_MSS 512
66
67 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
68 #define TCP_FASTRETRANS_THRESH 3
69
70 /* Maximal reordering. */
71 #define TCP_MAX_REORDERING 127
72
73 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
74 #define TCP_MAX_QUICKACKS 16U
75
76 /* urg_data states */
77 #define TCP_URG_VALID 0x0100
78 #define TCP_URG_NOTYET 0x0200
79 #define TCP_URG_READ 0x0400
80
81 #define TCP_RETR1 3 /*
82 * This is how many retries it does before it
83 * tries to figure out if the gateway is
84 * down. Minimal RFC value is 3; it corresponds
85 * to ~3sec-8min depending on RTO.
86 */
87
88 #define TCP_RETR2 15 /*
89 * This should take at least
90 * 90 minutes to time out.
91 * RFC1122 says that the limit is 100 sec.
92 * 15 is ~13-30min depending on RTO.
93 */
94
95 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
96 * connection: ~180sec is RFC minimum */
97
98 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
99 * connection: ~180sec is RFC minimum */
100
101
102 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
103 * socket. 7 is ~50sec-16min.
104 */
105
106
107 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
108 * state, about 60 seconds */
109 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
110 /* BSD style FIN_WAIT2 deadlock breaker.
111 * It used to be 3min, new value is 60sec,
112 * to combine FIN-WAIT-2 timeout with
113 * TIME-WAIT timer.
114 */
115
116 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
117 #if HZ >= 100
118 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
119 #define TCP_ATO_MIN ((unsigned)(HZ/25))
120 #else
121 #define TCP_DELACK_MIN 4U
122 #define TCP_ATO_MIN 4U
123 #endif
124 #define TCP_RTO_MAX ((unsigned)(120*HZ))
125 #define TCP_RTO_MIN ((unsigned)(HZ/5))
126 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
127
128 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
129 * for local resources.
130 */
131
132 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
133 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
134 #define TCP_KEEPALIVE_INTVL (75*HZ)
135
136 #define MAX_TCP_KEEPIDLE 32767
137 #define MAX_TCP_KEEPINTVL 32767
138 #define MAX_TCP_KEEPCNT 127
139 #define MAX_TCP_SYNCNT 127
140
141 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
142
143 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
144 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
145 * after this time. It should be equal
146 * (or greater than) TCP_TIMEWAIT_LEN
147 * to provide reliability equal to one
148 * provided by timewait state.
149 */
150 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
151 * timestamps. It must be less than
152 * minimal timewait lifetime.
153 */
154 /*
155 * TCP option
156 */
157
158 #define TCPOPT_NOP 1 /* Padding */
159 #define TCPOPT_EOL 0 /* End of options */
160 #define TCPOPT_MSS 2 /* Segment size negotiating */
161 #define TCPOPT_WINDOW 3 /* Window scaling */
162 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
163 #define TCPOPT_SACK 5 /* SACK Block */
164 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
165 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
166
167 /*
168 * TCP option lengths
169 */
170
171 #define TCPOLEN_MSS 4
172 #define TCPOLEN_WINDOW 3
173 #define TCPOLEN_SACK_PERM 2
174 #define TCPOLEN_TIMESTAMP 10
175 #define TCPOLEN_MD5SIG 18
176
177 /* But this is what stacks really send out. */
178 #define TCPOLEN_TSTAMP_ALIGNED 12
179 #define TCPOLEN_WSCALE_ALIGNED 4
180 #define TCPOLEN_SACKPERM_ALIGNED 4
181 #define TCPOLEN_SACK_BASE 2
182 #define TCPOLEN_SACK_BASE_ALIGNED 4
183 #define TCPOLEN_SACK_PERBLOCK 8
184 #define TCPOLEN_MD5SIG_ALIGNED 20
185
186 /* Flags in tp->nonagle */
187 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
188 #define TCP_NAGLE_CORK 2 /* Socket is corked */
189 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
190
191 extern struct inet_timewait_death_row tcp_death_row;
192
193 /* sysctl variables for tcp */
194 extern int sysctl_tcp_timestamps;
195 extern int sysctl_tcp_window_scaling;
196 extern int sysctl_tcp_sack;
197 extern int sysctl_tcp_fin_timeout;
198 extern int sysctl_tcp_keepalive_time;
199 extern int sysctl_tcp_keepalive_probes;
200 extern int sysctl_tcp_keepalive_intvl;
201 extern int sysctl_tcp_syn_retries;
202 extern int sysctl_tcp_synack_retries;
203 extern int sysctl_tcp_retries1;
204 extern int sysctl_tcp_retries2;
205 extern int sysctl_tcp_orphan_retries;
206 extern int sysctl_tcp_syncookies;
207 extern int sysctl_tcp_retrans_collapse;
208 extern int sysctl_tcp_stdurg;
209 extern int sysctl_tcp_rfc1337;
210 extern int sysctl_tcp_abort_on_overflow;
211 extern int sysctl_tcp_max_orphans;
212 extern int sysctl_tcp_fack;
213 extern int sysctl_tcp_reordering;
214 extern int sysctl_tcp_ecn;
215 extern int sysctl_tcp_dsack;
216 extern int sysctl_tcp_mem[3];
217 extern int sysctl_tcp_wmem[3];
218 extern int sysctl_tcp_rmem[3];
219 extern int sysctl_tcp_app_win;
220 extern int sysctl_tcp_adv_win_scale;
221 extern int sysctl_tcp_tw_reuse;
222 extern int sysctl_tcp_frto;
223 extern int sysctl_tcp_frto_response;
224 extern int sysctl_tcp_low_latency;
225 extern int sysctl_tcp_dma_copybreak;
226 extern int sysctl_tcp_nometrics_save;
227 extern int sysctl_tcp_moderate_rcvbuf;
228 extern int sysctl_tcp_tso_win_divisor;
229 extern int sysctl_tcp_abc;
230 extern int sysctl_tcp_mtu_probing;
231 extern int sysctl_tcp_base_mss;
232 extern int sysctl_tcp_workaround_signed_windows;
233 extern int sysctl_tcp_slow_start_after_idle;
234 extern int sysctl_tcp_max_ssthresh;
235
236 extern atomic_t tcp_memory_allocated;
237 extern atomic_t tcp_sockets_allocated;
238 extern int tcp_memory_pressure;
239
240 /*
241 * The next routines deal with comparing 32 bit unsigned ints
242 * and worry about wraparound (automatic with unsigned arithmetic).
243 */
244
245 static inline int before(__u32 seq1, __u32 seq2)
246 {
247 return (__s32)(seq1-seq2) < 0;
248 }
249 #define after(seq2, seq1) before(seq1, seq2)
250
251 /* is s2<=s1<=s3 ? */
252 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
253 {
254 return seq3 - seq2 >= seq1 - seq2;
255 }
256
257 static inline int tcp_too_many_orphans(struct sock *sk, int num)
258 {
259 return (num > sysctl_tcp_max_orphans) ||
260 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
261 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
262 }
263
264 extern struct proto tcp_prot;
265
266 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
267 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
268 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
269 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
270 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
271 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
272 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
273
274 extern void tcp_v4_err(struct sk_buff *skb, u32);
275
276 extern void tcp_shutdown (struct sock *sk, int how);
277
278 extern int tcp_v4_rcv(struct sk_buff *skb);
279
280 extern int tcp_v4_remember_stamp(struct sock *sk);
281
282 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
283
284 extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk,
285 struct msghdr *msg, size_t size);
286 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
287
288 extern int tcp_ioctl(struct sock *sk,
289 int cmd,
290 unsigned long arg);
291
292 extern int tcp_rcv_state_process(struct sock *sk,
293 struct sk_buff *skb,
294 struct tcphdr *th,
295 unsigned len);
296
297 extern int tcp_rcv_established(struct sock *sk,
298 struct sk_buff *skb,
299 struct tcphdr *th,
300 unsigned len);
301
302 extern void tcp_rcv_space_adjust(struct sock *sk);
303
304 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
305
306 extern int tcp_twsk_unique(struct sock *sk,
307 struct sock *sktw, void *twp);
308
309 extern void tcp_twsk_destructor(struct sock *sk);
310
311 static inline void tcp_dec_quickack_mode(struct sock *sk,
312 const unsigned int pkts)
313 {
314 struct inet_connection_sock *icsk = inet_csk(sk);
315
316 if (icsk->icsk_ack.quick) {
317 if (pkts >= icsk->icsk_ack.quick) {
318 icsk->icsk_ack.quick = 0;
319 /* Leaving quickack mode we deflate ATO. */
320 icsk->icsk_ack.ato = TCP_ATO_MIN;
321 } else
322 icsk->icsk_ack.quick -= pkts;
323 }
324 }
325
326 extern void tcp_enter_quickack_mode(struct sock *sk);
327
328 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
329 {
330 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
331 }
332
333 enum tcp_tw_status
334 {
335 TCP_TW_SUCCESS = 0,
336 TCP_TW_RST = 1,
337 TCP_TW_ACK = 2,
338 TCP_TW_SYN = 3
339 };
340
341
342 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
343 struct sk_buff *skb,
344 const struct tcphdr *th);
345
346 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
347 struct request_sock *req,
348 struct request_sock **prev);
349 extern int tcp_child_process(struct sock *parent,
350 struct sock *child,
351 struct sk_buff *skb);
352 extern int tcp_use_frto(struct sock *sk);
353 extern void tcp_enter_frto(struct sock *sk);
354 extern void tcp_enter_loss(struct sock *sk, int how);
355 extern void tcp_clear_retrans(struct tcp_sock *tp);
356 extern void tcp_update_metrics(struct sock *sk);
357
358 extern void tcp_close(struct sock *sk,
359 long timeout);
360 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
361
362 extern int tcp_getsockopt(struct sock *sk, int level,
363 int optname,
364 char __user *optval,
365 int __user *optlen);
366 extern int tcp_setsockopt(struct sock *sk, int level,
367 int optname, char __user *optval,
368 int optlen);
369 extern int compat_tcp_getsockopt(struct sock *sk,
370 int level, int optname,
371 char __user *optval, int __user *optlen);
372 extern int compat_tcp_setsockopt(struct sock *sk,
373 int level, int optname,
374 char __user *optval, int optlen);
375 extern void tcp_set_keepalive(struct sock *sk, int val);
376 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
377 struct msghdr *msg,
378 size_t len, int nonblock,
379 int flags, int *addr_len);
380
381 extern void tcp_parse_options(struct sk_buff *skb,
382 struct tcp_options_received *opt_rx,
383 int estab);
384
385 /*
386 * TCP v4 functions exported for the inet6 API
387 */
388
389 extern void tcp_v4_send_check(struct sock *sk, int len,
390 struct sk_buff *skb);
391
392 extern int tcp_v4_conn_request(struct sock *sk,
393 struct sk_buff *skb);
394
395 extern struct sock * tcp_create_openreq_child(struct sock *sk,
396 struct request_sock *req,
397 struct sk_buff *skb);
398
399 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
400 struct sk_buff *skb,
401 struct request_sock *req,
402 struct dst_entry *dst);
403
404 extern int tcp_v4_do_rcv(struct sock *sk,
405 struct sk_buff *skb);
406
407 extern int tcp_v4_connect(struct sock *sk,
408 struct sockaddr *uaddr,
409 int addr_len);
410
411 extern int tcp_connect(struct sock *sk);
412
413 extern struct sk_buff * tcp_make_synack(struct sock *sk,
414 struct dst_entry *dst,
415 struct request_sock *req);
416
417 extern int tcp_disconnect(struct sock *sk, int flags);
418
419 extern void tcp_unhash(struct sock *sk);
420
421 /* From syncookies.c */
422 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
423 struct ip_options *opt);
424 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
425 __u16 *mss);
426
427 /* tcp_output.c */
428
429 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
430 int nonagle);
431 extern int tcp_may_send_now(struct sock *sk);
432 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
433 extern void tcp_xmit_retransmit_queue(struct sock *);
434 extern void tcp_simple_retransmit(struct sock *);
435 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
436 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
437
438 extern void tcp_send_probe0(struct sock *);
439 extern void tcp_send_partial(struct sock *);
440 extern int tcp_write_wakeup(struct sock *);
441 extern void tcp_send_fin(struct sock *sk);
442 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
443 extern int tcp_send_synack(struct sock *);
444 extern void tcp_push_one(struct sock *, unsigned int mss_now);
445 extern void tcp_send_ack(struct sock *sk);
446 extern void tcp_send_delayed_ack(struct sock *sk);
447
448 /* tcp_input.c */
449 extern void tcp_cwnd_application_limited(struct sock *sk);
450
451 /* tcp_timer.c */
452 extern void tcp_init_xmit_timers(struct sock *);
453 static inline void tcp_clear_xmit_timers(struct sock *sk)
454 {
455 inet_csk_clear_xmit_timers(sk);
456 }
457
458 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
459 extern unsigned int tcp_current_mss(struct sock *sk, int large);
460
461 /* tcp.c */
462 extern void tcp_get_info(struct sock *, struct tcp_info *);
463
464 /* Read 'sendfile()'-style from a TCP socket */
465 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
466 unsigned int, size_t);
467 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
468 sk_read_actor_t recv_actor);
469
470 extern void tcp_initialize_rcv_mss(struct sock *sk);
471
472 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
473 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
474 extern void tcp_mtup_init(struct sock *sk);
475
476 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
477 {
478 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
479 ntohl(TCP_FLAG_ACK) |
480 snd_wnd);
481 }
482
483 static inline void tcp_fast_path_on(struct tcp_sock *tp)
484 {
485 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
486 }
487
488 static inline void tcp_fast_path_check(struct sock *sk)
489 {
490 struct tcp_sock *tp = tcp_sk(sk);
491
492 if (skb_queue_empty(&tp->out_of_order_queue) &&
493 tp->rcv_wnd &&
494 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
495 !tp->urg_data)
496 tcp_fast_path_on(tp);
497 }
498
499 /* Compute the actual receive window we are currently advertising.
500 * Rcv_nxt can be after the window if our peer push more data
501 * than the offered window.
502 */
503 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
504 {
505 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
506
507 if (win < 0)
508 win = 0;
509 return (u32) win;
510 }
511
512 /* Choose a new window, without checks for shrinking, and without
513 * scaling applied to the result. The caller does these things
514 * if necessary. This is a "raw" window selection.
515 */
516 extern u32 __tcp_select_window(struct sock *sk);
517
518 /* TCP timestamps are only 32-bits, this causes a slight
519 * complication on 64-bit systems since we store a snapshot
520 * of jiffies in the buffer control blocks below. We decided
521 * to use only the low 32-bits of jiffies and hide the ugly
522 * casts with the following macro.
523 */
524 #define tcp_time_stamp ((__u32)(jiffies))
525
526 /* This is what the send packet queuing engine uses to pass
527 * TCP per-packet control information to the transmission
528 * code. We also store the host-order sequence numbers in
529 * here too. This is 36 bytes on 32-bit architectures,
530 * 40 bytes on 64-bit machines, if this grows please adjust
531 * skbuff.h:skbuff->cb[xxx] size appropriately.
532 */
533 struct tcp_skb_cb {
534 union {
535 struct inet_skb_parm h4;
536 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
537 struct inet6_skb_parm h6;
538 #endif
539 } header; /* For incoming frames */
540 __u32 seq; /* Starting sequence number */
541 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
542 __u32 when; /* used to compute rtt's */
543 __u8 flags; /* TCP header flags. */
544
545 /* NOTE: These must match up to the flags byte in a
546 * real TCP header.
547 */
548 #define TCPCB_FLAG_FIN 0x01
549 #define TCPCB_FLAG_SYN 0x02
550 #define TCPCB_FLAG_RST 0x04
551 #define TCPCB_FLAG_PSH 0x08
552 #define TCPCB_FLAG_ACK 0x10
553 #define TCPCB_FLAG_URG 0x20
554 #define TCPCB_FLAG_ECE 0x40
555 #define TCPCB_FLAG_CWR 0x80
556
557 __u8 sacked; /* State flags for SACK/FACK. */
558 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
559 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
560 #define TCPCB_LOST 0x04 /* SKB is lost */
561 #define TCPCB_TAGBITS 0x07 /* All tag bits */
562
563 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
564 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
565
566 #define TCPCB_URG 0x20 /* Urgent pointer advanced here */
567
568 #define TCPCB_AT_TAIL (TCPCB_URG)
569
570 __u16 urg_ptr; /* Valid w/URG flags is set. */
571 __u32 ack_seq; /* Sequence number ACK'd */
572 };
573
574 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
575
576 #include <net/tcp_ecn.h>
577
578 /* Due to TSO, an SKB can be composed of multiple actual
579 * packets. To keep these tracked properly, we use this.
580 */
581 static inline int tcp_skb_pcount(const struct sk_buff *skb)
582 {
583 return skb_shinfo(skb)->gso_segs;
584 }
585
586 /* This is valid iff tcp_skb_pcount() > 1. */
587 static inline int tcp_skb_mss(const struct sk_buff *skb)
588 {
589 return skb_shinfo(skb)->gso_size;
590 }
591
592 static inline void tcp_dec_pcount_approx(__u32 *count,
593 const struct sk_buff *skb)
594 {
595 if (*count) {
596 *count -= tcp_skb_pcount(skb);
597 if ((int)*count < 0)
598 *count = 0;
599 }
600 }
601
602 static inline void tcp_packets_out_inc(struct sock *sk,
603 const struct sk_buff *skb)
604 {
605 struct tcp_sock *tp = tcp_sk(sk);
606 int orig = tp->packets_out;
607
608 tp->packets_out += tcp_skb_pcount(skb);
609 if (!orig)
610 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
611 inet_csk(sk)->icsk_rto, TCP_RTO_MAX);
612 }
613
614 static inline void tcp_packets_out_dec(struct tcp_sock *tp,
615 const struct sk_buff *skb)
616 {
617 tp->packets_out -= tcp_skb_pcount(skb);
618 }
619
620 /* Events passed to congestion control interface */
621 enum tcp_ca_event {
622 CA_EVENT_TX_START, /* first transmit when no packets in flight */
623 CA_EVENT_CWND_RESTART, /* congestion window restart */
624 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
625 CA_EVENT_FRTO, /* fast recovery timeout */
626 CA_EVENT_LOSS, /* loss timeout */
627 CA_EVENT_FAST_ACK, /* in sequence ack */
628 CA_EVENT_SLOW_ACK, /* other ack */
629 };
630
631 /*
632 * Interface for adding new TCP congestion control handlers
633 */
634 #define TCP_CA_NAME_MAX 16
635 #define TCP_CA_MAX 128
636 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
637
638 #define TCP_CONG_NON_RESTRICTED 0x1
639 #define TCP_CONG_RTT_STAMP 0x2
640
641 struct tcp_congestion_ops {
642 struct list_head list;
643 unsigned long flags;
644
645 /* initialize private data (optional) */
646 void (*init)(struct sock *sk);
647 /* cleanup private data (optional) */
648 void (*release)(struct sock *sk);
649
650 /* return slow start threshold (required) */
651 u32 (*ssthresh)(struct sock *sk);
652 /* lower bound for congestion window (optional) */
653 u32 (*min_cwnd)(const struct sock *sk);
654 /* do new cwnd calculation (required) */
655 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight, int good_ack);
656 /* call before changing ca_state (optional) */
657 void (*set_state)(struct sock *sk, u8 new_state);
658 /* call when cwnd event occurs (optional) */
659 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
660 /* new value of cwnd after loss (optional) */
661 u32 (*undo_cwnd)(struct sock *sk);
662 /* hook for packet ack accounting (optional) */
663 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
664 /* get info for inet_diag (optional) */
665 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
666
667 char name[TCP_CA_NAME_MAX];
668 struct module *owner;
669 };
670
671 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
672 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
673
674 extern void tcp_init_congestion_control(struct sock *sk);
675 extern void tcp_cleanup_congestion_control(struct sock *sk);
676 extern int tcp_set_default_congestion_control(const char *name);
677 extern void tcp_get_default_congestion_control(char *name);
678 extern void tcp_get_available_congestion_control(char *buf, size_t len);
679 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
680 extern int tcp_set_allowed_congestion_control(char *allowed);
681 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
682 extern void tcp_slow_start(struct tcp_sock *tp);
683
684 extern struct tcp_congestion_ops tcp_init_congestion_ops;
685 extern u32 tcp_reno_ssthresh(struct sock *sk);
686 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight, int flag);
687 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
688 extern struct tcp_congestion_ops tcp_reno;
689
690 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
691 {
692 struct inet_connection_sock *icsk = inet_csk(sk);
693
694 if (icsk->icsk_ca_ops->set_state)
695 icsk->icsk_ca_ops->set_state(sk, ca_state);
696 icsk->icsk_ca_state = ca_state;
697 }
698
699 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
700 {
701 const struct inet_connection_sock *icsk = inet_csk(sk);
702
703 if (icsk->icsk_ca_ops->cwnd_event)
704 icsk->icsk_ca_ops->cwnd_event(sk, event);
705 }
706
707 /* This determines how many packets are "in the network" to the best
708 * of our knowledge. In many cases it is conservative, but where
709 * detailed information is available from the receiver (via SACK
710 * blocks etc.) we can make more aggressive calculations.
711 *
712 * Use this for decisions involving congestion control, use just
713 * tp->packets_out to determine if the send queue is empty or not.
714 *
715 * Read this equation as:
716 *
717 * "Packets sent once on transmission queue" MINUS
718 * "Packets left network, but not honestly ACKed yet" PLUS
719 * "Packets fast retransmitted"
720 */
721 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
722 {
723 return (tp->packets_out - tp->left_out + tp->retrans_out);
724 }
725
726 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
727 * The exception is rate halving phase, when cwnd is decreasing towards
728 * ssthresh.
729 */
730 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
731 {
732 const struct tcp_sock *tp = tcp_sk(sk);
733 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
734 return tp->snd_ssthresh;
735 else
736 return max(tp->snd_ssthresh,
737 ((tp->snd_cwnd >> 1) +
738 (tp->snd_cwnd >> 2)));
739 }
740
741 static inline void tcp_sync_left_out(struct tcp_sock *tp)
742 {
743 BUG_ON(tp->rx_opt.sack_ok &&
744 (tp->sacked_out + tp->lost_out > tp->packets_out));
745 tp->left_out = tp->sacked_out + tp->lost_out;
746 }
747
748 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
749 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
750
751 /* Slow start with delack produces 3 packets of burst, so that
752 * it is safe "de facto".
753 */
754 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
755 {
756 return 3;
757 }
758
759 /* RFC2861 Check whether we are limited by application or congestion window
760 * This is the inverse of cwnd check in tcp_tso_should_defer
761 */
762 static inline int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight)
763 {
764 const struct tcp_sock *tp = tcp_sk(sk);
765 u32 left;
766
767 if (in_flight >= tp->snd_cwnd)
768 return 1;
769
770 if (!sk_can_gso(sk))
771 return 0;
772
773 left = tp->snd_cwnd - in_flight;
774 if (sysctl_tcp_tso_win_divisor)
775 return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd;
776 else
777 return left <= tcp_max_burst(tp);
778 }
779
780 static inline void tcp_minshall_update(struct tcp_sock *tp, int mss,
781 const struct sk_buff *skb)
782 {
783 if (skb->len < mss)
784 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
785 }
786
787 static inline void tcp_check_probe_timer(struct sock *sk)
788 {
789 struct tcp_sock *tp = tcp_sk(sk);
790 const struct inet_connection_sock *icsk = inet_csk(sk);
791
792 if (!tp->packets_out && !icsk->icsk_pending)
793 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
794 icsk->icsk_rto, TCP_RTO_MAX);
795 }
796
797 static inline void tcp_push_pending_frames(struct sock *sk)
798 {
799 struct tcp_sock *tp = tcp_sk(sk);
800
801 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
802 }
803
804 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
805 {
806 tp->snd_wl1 = seq;
807 }
808
809 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
810 {
811 tp->snd_wl1 = seq;
812 }
813
814 /*
815 * Calculate(/check) TCP checksum
816 */
817 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
818 __be32 daddr, __wsum base)
819 {
820 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
821 }
822
823 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
824 {
825 return __skb_checksum_complete(skb);
826 }
827
828 static inline int tcp_checksum_complete(struct sk_buff *skb)
829 {
830 return !skb_csum_unnecessary(skb) &&
831 __tcp_checksum_complete(skb);
832 }
833
834 /* Prequeue for VJ style copy to user, combined with checksumming. */
835
836 static inline void tcp_prequeue_init(struct tcp_sock *tp)
837 {
838 tp->ucopy.task = NULL;
839 tp->ucopy.len = 0;
840 tp->ucopy.memory = 0;
841 skb_queue_head_init(&tp->ucopy.prequeue);
842 #ifdef CONFIG_NET_DMA
843 tp->ucopy.dma_chan = NULL;
844 tp->ucopy.wakeup = 0;
845 tp->ucopy.pinned_list = NULL;
846 tp->ucopy.dma_cookie = 0;
847 #endif
848 }
849
850 /* Packet is added to VJ-style prequeue for processing in process
851 * context, if a reader task is waiting. Apparently, this exciting
852 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
853 * failed somewhere. Latency? Burstiness? Well, at least now we will
854 * see, why it failed. 8)8) --ANK
855 *
856 * NOTE: is this not too big to inline?
857 */
858 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
859 {
860 struct tcp_sock *tp = tcp_sk(sk);
861
862 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
863 __skb_queue_tail(&tp->ucopy.prequeue, skb);
864 tp->ucopy.memory += skb->truesize;
865 if (tp->ucopy.memory > sk->sk_rcvbuf) {
866 struct sk_buff *skb1;
867
868 BUG_ON(sock_owned_by_user(sk));
869
870 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
871 sk->sk_backlog_rcv(sk, skb1);
872 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
873 }
874
875 tp->ucopy.memory = 0;
876 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
877 wake_up_interruptible(sk->sk_sleep);
878 if (!inet_csk_ack_scheduled(sk))
879 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
880 (3 * TCP_RTO_MIN) / 4,
881 TCP_RTO_MAX);
882 }
883 return 1;
884 }
885 return 0;
886 }
887
888
889 #undef STATE_TRACE
890
891 #ifdef STATE_TRACE
892 static const char *statename[]={
893 "Unused","Established","Syn Sent","Syn Recv",
894 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
895 "Close Wait","Last ACK","Listen","Closing"
896 };
897 #endif
898
899 static inline void tcp_set_state(struct sock *sk, int state)
900 {
901 int oldstate = sk->sk_state;
902
903 switch (state) {
904 case TCP_ESTABLISHED:
905 if (oldstate != TCP_ESTABLISHED)
906 TCP_INC_STATS(TCP_MIB_CURRESTAB);
907 break;
908
909 case TCP_CLOSE:
910 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
911 TCP_INC_STATS(TCP_MIB_ESTABRESETS);
912
913 sk->sk_prot->unhash(sk);
914 if (inet_csk(sk)->icsk_bind_hash &&
915 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
916 inet_put_port(&tcp_hashinfo, sk);
917 /* fall through */
918 default:
919 if (oldstate==TCP_ESTABLISHED)
920 TCP_DEC_STATS(TCP_MIB_CURRESTAB);
921 }
922
923 /* Change state AFTER socket is unhashed to avoid closed
924 * socket sitting in hash tables.
925 */
926 sk->sk_state = state;
927
928 #ifdef STATE_TRACE
929 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]);
930 #endif
931 }
932
933 extern void tcp_done(struct sock *sk);
934
935 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
936 {
937 rx_opt->dsack = 0;
938 rx_opt->eff_sacks = 0;
939 rx_opt->num_sacks = 0;
940 }
941
942 /* Determine a window scaling and initial window to offer. */
943 extern void tcp_select_initial_window(int __space, __u32 mss,
944 __u32 *rcv_wnd, __u32 *window_clamp,
945 int wscale_ok, __u8 *rcv_wscale);
946
947 static inline int tcp_win_from_space(int space)
948 {
949 return sysctl_tcp_adv_win_scale<=0 ?
950 (space>>(-sysctl_tcp_adv_win_scale)) :
951 space - (space>>sysctl_tcp_adv_win_scale);
952 }
953
954 /* Note: caller must be prepared to deal with negative returns */
955 static inline int tcp_space(const struct sock *sk)
956 {
957 return tcp_win_from_space(sk->sk_rcvbuf -
958 atomic_read(&sk->sk_rmem_alloc));
959 }
960
961 static inline int tcp_full_space(const struct sock *sk)
962 {
963 return tcp_win_from_space(sk->sk_rcvbuf);
964 }
965
966 static inline void tcp_openreq_init(struct request_sock *req,
967 struct tcp_options_received *rx_opt,
968 struct sk_buff *skb)
969 {
970 struct inet_request_sock *ireq = inet_rsk(req);
971
972 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;
980 ireq->acked = 0;
981 ireq->ecn_ok = 0;
982 ireq->rmt_port = tcp_hdr(skb)->source;
983 }
984
985 extern void tcp_enter_memory_pressure(void);
986
987 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
988 {
989 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
990 }
991
992 static inline int keepalive_time_when(const struct tcp_sock *tp)
993 {
994 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
995 }
996
997 static inline int tcp_fin_time(const struct sock *sk)
998 {
999 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1000 const int rto = inet_csk(sk)->icsk_rto;
1001
1002 if (fin_timeout < (rto << 2) - (rto >> 1))
1003 fin_timeout = (rto << 2) - (rto >> 1);
1004
1005 return fin_timeout;
1006 }
1007
1008 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1009 {
1010 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1011 return 0;
1012 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1013 return 0;
1014
1015 /* RST segments are not recommended to carry timestamp,
1016 and, if they do, it is recommended to ignore PAWS because
1017 "their cleanup function should take precedence over timestamps."
1018 Certainly, it is mistake. It is necessary to understand the reasons
1019 of this constraint to relax it: if peer reboots, clock may go
1020 out-of-sync and half-open connections will not be reset.
1021 Actually, the problem would be not existing if all
1022 the implementations followed draft about maintaining clock
1023 via reboots. Linux-2.2 DOES NOT!
1024
1025 However, we can relax time bounds for RST segments to MSL.
1026 */
1027 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1028 return 0;
1029 return 1;
1030 }
1031
1032 #define TCP_CHECK_TIMER(sk) do { } while (0)
1033
1034 static inline void tcp_mib_init(void)
1035 {
1036 /* See RFC 2012 */
1037 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1038 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1039 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1040 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
1041 }
1042
1043 /*from STCP */
1044 static inline void clear_all_retrans_hints(struct tcp_sock *tp){
1045 tp->lost_skb_hint = NULL;
1046 tp->scoreboard_skb_hint = NULL;
1047 tp->retransmit_skb_hint = NULL;
1048 tp->forward_skb_hint = NULL;
1049 tp->fastpath_skb_hint = NULL;
1050 }
1051
1052 /* MD5 Signature */
1053 struct crypto_hash;
1054
1055 /* - key database */
1056 struct tcp_md5sig_key {
1057 u8 *key;
1058 u8 keylen;
1059 };
1060
1061 struct tcp4_md5sig_key {
1062 u8 *key;
1063 u16 keylen;
1064 __be32 addr;
1065 };
1066
1067 struct tcp6_md5sig_key {
1068 u8 *key;
1069 u16 keylen;
1070 #if 0
1071 u32 scope_id; /* XXX */
1072 #endif
1073 struct in6_addr addr;
1074 };
1075
1076 /* - sock block */
1077 struct tcp_md5sig_info {
1078 struct tcp4_md5sig_key *keys4;
1079 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1080 struct tcp6_md5sig_key *keys6;
1081 u32 entries6;
1082 u32 alloced6;
1083 #endif
1084 u32 entries4;
1085 u32 alloced4;
1086 };
1087
1088 /* - pseudo header */
1089 struct tcp4_pseudohdr {
1090 __be32 saddr;
1091 __be32 daddr;
1092 __u8 pad;
1093 __u8 protocol;
1094 __be16 len;
1095 };
1096
1097 struct tcp6_pseudohdr {
1098 struct in6_addr saddr;
1099 struct in6_addr daddr;
1100 __be32 len;
1101 __be32 protocol; /* including padding */
1102 };
1103
1104 union tcp_md5sum_block {
1105 struct tcp4_pseudohdr ip4;
1106 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1107 struct tcp6_pseudohdr ip6;
1108 #endif
1109 };
1110
1111 /* - pool: digest algorithm, hash description and scratch buffer */
1112 struct tcp_md5sig_pool {
1113 struct hash_desc md5_desc;
1114 union tcp_md5sum_block md5_blk;
1115 };
1116
1117 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1118
1119 /* - functions */
1120 extern int tcp_v4_calc_md5_hash(char *md5_hash,
1121 struct tcp_md5sig_key *key,
1122 struct sock *sk,
1123 struct dst_entry *dst,
1124 struct request_sock *req,
1125 struct tcphdr *th,
1126 int protocol, int tcplen);
1127 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1128 struct sock *addr_sk);
1129
1130 extern int tcp_v4_md5_do_add(struct sock *sk,
1131 __be32 addr,
1132 u8 *newkey,
1133 u8 newkeylen);
1134
1135 extern int tcp_v4_md5_do_del(struct sock *sk,
1136 __be32 addr);
1137
1138 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1139 extern void tcp_free_md5sig_pool(void);
1140
1141 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1142 extern void __tcp_put_md5sig_pool(void);
1143
1144 static inline
1145 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1146 {
1147 int cpu = get_cpu();
1148 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1149 if (!ret)
1150 put_cpu();
1151 return ret;
1152 }
1153
1154 static inline void tcp_put_md5sig_pool(void)
1155 {
1156 __tcp_put_md5sig_pool();
1157 put_cpu();
1158 }
1159
1160 /* write queue abstraction */
1161 static inline void tcp_write_queue_purge(struct sock *sk)
1162 {
1163 struct sk_buff *skb;
1164
1165 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1166 sk_stream_free_skb(sk, skb);
1167 sk_stream_mem_reclaim(sk);
1168 }
1169
1170 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1171 {
1172 struct sk_buff *skb = sk->sk_write_queue.next;
1173 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1174 return NULL;
1175 return skb;
1176 }
1177
1178 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1179 {
1180 struct sk_buff *skb = sk->sk_write_queue.prev;
1181 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1182 return NULL;
1183 return skb;
1184 }
1185
1186 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1187 {
1188 return skb->next;
1189 }
1190
1191 #define tcp_for_write_queue(skb, sk) \
1192 for (skb = (sk)->sk_write_queue.next; \
1193 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1194 skb = skb->next)
1195
1196 #define tcp_for_write_queue_from(skb, sk) \
1197 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\
1198 skb = skb->next)
1199
1200 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1201 {
1202 return sk->sk_send_head;
1203 }
1204
1205 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1206 {
1207 struct tcp_sock *tp = tcp_sk(sk);
1208
1209 sk->sk_send_head = skb->next;
1210 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
1211 sk->sk_send_head = NULL;
1212 /* Don't override Nagle indefinately with F-RTO */
1213 if (tp->frto_counter == 2)
1214 tp->frto_counter = 3;
1215 }
1216
1217 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1218 {
1219 if (sk->sk_send_head == skb_unlinked)
1220 sk->sk_send_head = NULL;
1221 }
1222
1223 static inline void tcp_init_send_head(struct sock *sk)
1224 {
1225 sk->sk_send_head = NULL;
1226 }
1227
1228 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1229 {
1230 __skb_queue_tail(&sk->sk_write_queue, skb);
1231 }
1232
1233 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1234 {
1235 __tcp_add_write_queue_tail(sk, skb);
1236
1237 /* Queue it, remembering where we must start sending. */
1238 if (sk->sk_send_head == NULL)
1239 sk->sk_send_head = skb;
1240 }
1241
1242 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1243 {
1244 __skb_queue_head(&sk->sk_write_queue, skb);
1245 }
1246
1247 /* Insert buff after skb on the write queue of sk. */
1248 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1249 struct sk_buff *buff,
1250 struct sock *sk)
1251 {
1252 __skb_append(skb, buff, &sk->sk_write_queue);
1253 }
1254
1255 /* Insert skb between prev and next on the write queue of sk. */
1256 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1257 struct sk_buff *skb,
1258 struct sock *sk)
1259 {
1260 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
1261 }
1262
1263 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1264 {
1265 __skb_unlink(skb, &sk->sk_write_queue);
1266 }
1267
1268 static inline int tcp_skb_is_last(const struct sock *sk,
1269 const struct sk_buff *skb)
1270 {
1271 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1272 }
1273
1274 static inline int tcp_write_queue_empty(struct sock *sk)
1275 {
1276 return skb_queue_empty(&sk->sk_write_queue);
1277 }
1278
1279 /* /proc */
1280 enum tcp_seq_states {
1281 TCP_SEQ_STATE_LISTENING,
1282 TCP_SEQ_STATE_OPENREQ,
1283 TCP_SEQ_STATE_ESTABLISHED,
1284 TCP_SEQ_STATE_TIME_WAIT,
1285 };
1286
1287 struct tcp_seq_afinfo {
1288 struct module *owner;
1289 char *name;
1290 sa_family_t family;
1291 int (*seq_show) (struct seq_file *m, void *v);
1292 struct file_operations *seq_fops;
1293 };
1294
1295 struct tcp_iter_state {
1296 sa_family_t family;
1297 enum tcp_seq_states state;
1298 struct sock *syn_wait_sk;
1299 int bucket, sbucket, num, uid;
1300 struct seq_operations seq_ops;
1301 };
1302
1303 extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo);
1304 extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo);
1305
1306 extern struct request_sock_ops tcp_request_sock_ops;
1307
1308 extern int tcp_v4_destroy_sock(struct sock *sk);
1309
1310 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1311 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1312
1313 #ifdef CONFIG_PROC_FS
1314 extern int tcp4_proc_init(void);
1315 extern void tcp4_proc_exit(void);
1316 #endif
1317
1318 /* TCP af-specific functions */
1319 struct tcp_sock_af_ops {
1320 #ifdef CONFIG_TCP_MD5SIG
1321 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1322 struct sock *addr_sk);
1323 int (*calc_md5_hash) (char *location,
1324 struct tcp_md5sig_key *md5,
1325 struct sock *sk,
1326 struct dst_entry *dst,
1327 struct request_sock *req,
1328 struct tcphdr *th,
1329 int protocol, int len);
1330 int (*md5_add) (struct sock *sk,
1331 struct sock *addr_sk,
1332 u8 *newkey,
1333 u8 len);
1334 int (*md5_parse) (struct sock *sk,
1335 char __user *optval,
1336 int optlen);
1337 #endif
1338 };
1339
1340 struct tcp_request_sock_ops {
1341 #ifdef CONFIG_TCP_MD5SIG
1342 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1343 struct request_sock *req);
1344 #endif
1345 };
1346
1347 extern void tcp_v4_init(struct net_proto_family *ops);
1348 extern void tcp_init(void);
1349
1350 #endif /* _TCP_H */
Linux kernel - Deliverables
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