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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394...
[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
258 extern struct proto tcp_prot;
259
260 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
261 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
262 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
263 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
264 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
265 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
266 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
267
268 extern void tcp_v4_err(struct sk_buff *skb, u32);
269
270 extern void tcp_shutdown (struct sock *sk, int how);
271
272 extern int tcp_v4_rcv(struct sk_buff *skb);
273
274 extern int tcp_v4_remember_stamp(struct sock *sk);
275
276 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
277
278 extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk,
279 struct msghdr *msg, size_t size);
280 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
281
282 extern int tcp_ioctl(struct sock *sk,
283 int cmd,
284 unsigned long arg);
285
286 extern int tcp_rcv_state_process(struct sock *sk,
287 struct sk_buff *skb,
288 struct tcphdr *th,
289 unsigned len);
290
291 extern int tcp_rcv_established(struct sock *sk,
292 struct sk_buff *skb,
293 struct tcphdr *th,
294 unsigned len);
295
296 extern void tcp_rcv_space_adjust(struct sock *sk);
297
298 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
299
300 extern int tcp_twsk_unique(struct sock *sk,
301 struct sock *sktw, void *twp);
302
303 extern void tcp_twsk_destructor(struct sock *sk);
304
305 static inline void tcp_dec_quickack_mode(struct sock *sk,
306 const unsigned int pkts)
307 {
308 struct inet_connection_sock *icsk = inet_csk(sk);
309
310 if (icsk->icsk_ack.quick) {
311 if (pkts >= icsk->icsk_ack.quick) {
312 icsk->icsk_ack.quick = 0;
313 /* Leaving quickack mode we deflate ATO. */
314 icsk->icsk_ack.ato = TCP_ATO_MIN;
315 } else
316 icsk->icsk_ack.quick -= pkts;
317 }
318 }
319
320 extern void tcp_enter_quickack_mode(struct sock *sk);
321
322 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
323 {
324 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
325 }
326
327 enum tcp_tw_status
328 {
329 TCP_TW_SUCCESS = 0,
330 TCP_TW_RST = 1,
331 TCP_TW_ACK = 2,
332 TCP_TW_SYN = 3
333 };
334
335
336 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
337 struct sk_buff *skb,
338 const struct tcphdr *th);
339
340 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
341 struct request_sock *req,
342 struct request_sock **prev);
343 extern int tcp_child_process(struct sock *parent,
344 struct sock *child,
345 struct sk_buff *skb);
346 extern int tcp_use_frto(struct sock *sk);
347 extern void tcp_enter_frto(struct sock *sk);
348 extern void tcp_enter_loss(struct sock *sk, int how);
349 extern void tcp_clear_retrans(struct tcp_sock *tp);
350 extern void tcp_update_metrics(struct sock *sk);
351
352 extern void tcp_close(struct sock *sk,
353 long timeout);
354 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
355
356 extern int tcp_getsockopt(struct sock *sk, int level,
357 int optname,
358 char __user *optval,
359 int __user *optlen);
360 extern int tcp_setsockopt(struct sock *sk, int level,
361 int optname, char __user *optval,
362 int optlen);
363 extern int compat_tcp_getsockopt(struct sock *sk,
364 int level, int optname,
365 char __user *optval, int __user *optlen);
366 extern int compat_tcp_setsockopt(struct sock *sk,
367 int level, int optname,
368 char __user *optval, int optlen);
369 extern void tcp_set_keepalive(struct sock *sk, int val);
370 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
371 struct msghdr *msg,
372 size_t len, int nonblock,
373 int flags, int *addr_len);
374
375 extern void tcp_parse_options(struct sk_buff *skb,
376 struct tcp_options_received *opt_rx,
377 int estab);
378
379 /*
380 * TCP v4 functions exported for the inet6 API
381 */
382
383 extern void tcp_v4_send_check(struct sock *sk, int len,
384 struct sk_buff *skb);
385
386 extern int tcp_v4_conn_request(struct sock *sk,
387 struct sk_buff *skb);
388
389 extern struct sock * tcp_create_openreq_child(struct sock *sk,
390 struct request_sock *req,
391 struct sk_buff *skb);
392
393 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
394 struct sk_buff *skb,
395 struct request_sock *req,
396 struct dst_entry *dst);
397
398 extern int tcp_v4_do_rcv(struct sock *sk,
399 struct sk_buff *skb);
400
401 extern int tcp_v4_connect(struct sock *sk,
402 struct sockaddr *uaddr,
403 int addr_len);
404
405 extern int tcp_connect(struct sock *sk);
406
407 extern struct sk_buff * tcp_make_synack(struct sock *sk,
408 struct dst_entry *dst,
409 struct request_sock *req);
410
411 extern int tcp_disconnect(struct sock *sk, int flags);
412
413 extern void tcp_unhash(struct sock *sk);
414
415 /* From syncookies.c */
416 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
417 struct ip_options *opt);
418 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
419 __u16 *mss);
420
421 /* tcp_output.c */
422
423 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
424 int nonagle);
425 extern int tcp_may_send_now(struct sock *sk);
426 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
427 extern void tcp_xmit_retransmit_queue(struct sock *);
428 extern void tcp_simple_retransmit(struct sock *);
429 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
430 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
431
432 extern void tcp_send_probe0(struct sock *);
433 extern void tcp_send_partial(struct sock *);
434 extern int tcp_write_wakeup(struct sock *);
435 extern void tcp_send_fin(struct sock *sk);
436 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
437 extern int tcp_send_synack(struct sock *);
438 extern void tcp_push_one(struct sock *, unsigned int mss_now);
439 extern void tcp_send_ack(struct sock *sk);
440 extern void tcp_send_delayed_ack(struct sock *sk);
441
442 /* tcp_input.c */
443 extern void tcp_cwnd_application_limited(struct sock *sk);
444
445 /* tcp_timer.c */
446 extern void tcp_init_xmit_timers(struct sock *);
447 static inline void tcp_clear_xmit_timers(struct sock *sk)
448 {
449 inet_csk_clear_xmit_timers(sk);
450 }
451
452 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
453 extern unsigned int tcp_current_mss(struct sock *sk, int large);
454
455 /* tcp.c */
456 extern void tcp_get_info(struct sock *, struct tcp_info *);
457
458 /* Read 'sendfile()'-style from a TCP socket */
459 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
460 unsigned int, size_t);
461 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
462 sk_read_actor_t recv_actor);
463
464 extern void tcp_initialize_rcv_mss(struct sock *sk);
465
466 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
467 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
468 extern void tcp_mtup_init(struct sock *sk);
469
470 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
471 {
472 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
473 ntohl(TCP_FLAG_ACK) |
474 snd_wnd);
475 }
476
477 static inline void tcp_fast_path_on(struct tcp_sock *tp)
478 {
479 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
480 }
481
482 static inline void tcp_fast_path_check(struct sock *sk)
483 {
484 struct tcp_sock *tp = tcp_sk(sk);
485
486 if (skb_queue_empty(&tp->out_of_order_queue) &&
487 tp->rcv_wnd &&
488 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
489 !tp->urg_data)
490 tcp_fast_path_on(tp);
491 }
492
493 /* Compute the actual receive window we are currently advertising.
494 * Rcv_nxt can be after the window if our peer push more data
495 * than the offered window.
496 */
497 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
498 {
499 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
500
501 if (win < 0)
502 win = 0;
503 return (u32) win;
504 }
505
506 /* Choose a new window, without checks for shrinking, and without
507 * scaling applied to the result. The caller does these things
508 * if necessary. This is a "raw" window selection.
509 */
510 extern u32 __tcp_select_window(struct sock *sk);
511
512 /* TCP timestamps are only 32-bits, this causes a slight
513 * complication on 64-bit systems since we store a snapshot
514 * of jiffies in the buffer control blocks below. We decided
515 * to use only the low 32-bits of jiffies and hide the ugly
516 * casts with the following macro.
517 */
518 #define tcp_time_stamp ((__u32)(jiffies))
519
520 /* This is what the send packet queuing engine uses to pass
521 * TCP per-packet control information to the transmission
522 * code. We also store the host-order sequence numbers in
523 * here too. This is 36 bytes on 32-bit architectures,
524 * 40 bytes on 64-bit machines, if this grows please adjust
525 * skbuff.h:skbuff->cb[xxx] size appropriately.
526 */
527 struct tcp_skb_cb {
528 union {
529 struct inet_skb_parm h4;
530 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
531 struct inet6_skb_parm h6;
532 #endif
533 } header; /* For incoming frames */
534 __u32 seq; /* Starting sequence number */
535 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
536 __u32 when; /* used to compute rtt's */
537 __u8 flags; /* TCP header flags. */
538
539 /* NOTE: These must match up to the flags byte in a
540 * real TCP header.
541 */
542 #define TCPCB_FLAG_FIN 0x01
543 #define TCPCB_FLAG_SYN 0x02
544 #define TCPCB_FLAG_RST 0x04
545 #define TCPCB_FLAG_PSH 0x08
546 #define TCPCB_FLAG_ACK 0x10
547 #define TCPCB_FLAG_URG 0x20
548 #define TCPCB_FLAG_ECE 0x40
549 #define TCPCB_FLAG_CWR 0x80
550
551 __u8 sacked; /* State flags for SACK/FACK. */
552 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
553 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
554 #define TCPCB_LOST 0x04 /* SKB is lost */
555 #define TCPCB_TAGBITS 0x07 /* All tag bits */
556
557 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
558 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
559
560 #define TCPCB_URG 0x20 /* Urgent pointer advanced here */
561
562 #define TCPCB_AT_TAIL (TCPCB_URG)
563
564 __u16 urg_ptr; /* Valid w/URG flags is set. */
565 __u32 ack_seq; /* Sequence number ACK'd */
566 };
567
568 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
569
570 #include <net/tcp_ecn.h>
571
572 /* Due to TSO, an SKB can be composed of multiple actual
573 * packets. To keep these tracked properly, we use this.
574 */
575 static inline int tcp_skb_pcount(const struct sk_buff *skb)
576 {
577 return skb_shinfo(skb)->gso_segs;
578 }
579
580 /* This is valid iff tcp_skb_pcount() > 1. */
581 static inline int tcp_skb_mss(const struct sk_buff *skb)
582 {
583 return skb_shinfo(skb)->gso_size;
584 }
585
586 static inline void tcp_dec_pcount_approx(__u32 *count,
587 const struct sk_buff *skb)
588 {
589 if (*count) {
590 *count -= tcp_skb_pcount(skb);
591 if ((int)*count < 0)
592 *count = 0;
593 }
594 }
595
596 static inline void tcp_packets_out_inc(struct sock *sk,
597 const struct sk_buff *skb)
598 {
599 struct tcp_sock *tp = tcp_sk(sk);
600 int orig = tp->packets_out;
601
602 tp->packets_out += tcp_skb_pcount(skb);
603 if (!orig)
604 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
605 inet_csk(sk)->icsk_rto, TCP_RTO_MAX);
606 }
607
608 static inline void tcp_packets_out_dec(struct tcp_sock *tp,
609 const struct sk_buff *skb)
610 {
611 tp->packets_out -= tcp_skb_pcount(skb);
612 }
613
614 /* Events passed to congestion control interface */
615 enum tcp_ca_event {
616 CA_EVENT_TX_START, /* first transmit when no packets in flight */
617 CA_EVENT_CWND_RESTART, /* congestion window restart */
618 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
619 CA_EVENT_FRTO, /* fast recovery timeout */
620 CA_EVENT_LOSS, /* loss timeout */
621 CA_EVENT_FAST_ACK, /* in sequence ack */
622 CA_EVENT_SLOW_ACK, /* other ack */
623 };
624
625 /*
626 * Interface for adding new TCP congestion control handlers
627 */
628 #define TCP_CA_NAME_MAX 16
629 #define TCP_CA_MAX 128
630 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
631
632 #define TCP_CONG_NON_RESTRICTED 0x1
633 #define TCP_CONG_RTT_STAMP 0x2
634
635 struct tcp_congestion_ops {
636 struct list_head list;
637 unsigned long flags;
638
639 /* initialize private data (optional) */
640 void (*init)(struct sock *sk);
641 /* cleanup private data (optional) */
642 void (*release)(struct sock *sk);
643
644 /* return slow start threshold (required) */
645 u32 (*ssthresh)(struct sock *sk);
646 /* lower bound for congestion window (optional) */
647 u32 (*min_cwnd)(const struct sock *sk);
648 /* do new cwnd calculation (required) */
649 void (*cong_avoid)(struct sock *sk, u32 ack,
650 u32 rtt, u32 in_flight, int good_ack);
651 /* call before changing ca_state (optional) */
652 void (*set_state)(struct sock *sk, u8 new_state);
653 /* call when cwnd event occurs (optional) */
654 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
655 /* new value of cwnd after loss (optional) */
656 u32 (*undo_cwnd)(struct sock *sk);
657 /* hook for packet ack accounting (optional) */
658 void (*pkts_acked)(struct sock *sk, u32 num_acked, ktime_t last);
659 /* get info for inet_diag (optional) */
660 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
661
662 char name[TCP_CA_NAME_MAX];
663 struct module *owner;
664 };
665
666 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
667 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
668
669 extern void tcp_init_congestion_control(struct sock *sk);
670 extern void tcp_cleanup_congestion_control(struct sock *sk);
671 extern int tcp_set_default_congestion_control(const char *name);
672 extern void tcp_get_default_congestion_control(char *name);
673 extern void tcp_get_available_congestion_control(char *buf, size_t len);
674 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
675 extern int tcp_set_allowed_congestion_control(char *allowed);
676 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
677 extern void tcp_slow_start(struct tcp_sock *tp);
678
679 extern struct tcp_congestion_ops tcp_init_congestion_ops;
680 extern u32 tcp_reno_ssthresh(struct sock *sk);
681 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack,
682 u32 rtt, u32 in_flight, int flag);
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 /* This determines how many packets are "in the network" to the best
704 * of our knowledge. In many cases it is conservative, but where
705 * detailed information is available from the receiver (via SACK
706 * blocks etc.) we can make more aggressive calculations.
707 *
708 * Use this for decisions involving congestion control, use just
709 * tp->packets_out to determine if the send queue is empty or not.
710 *
711 * Read this equation as:
712 *
713 * "Packets sent once on transmission queue" MINUS
714 * "Packets left network, but not honestly ACKed yet" PLUS
715 * "Packets fast retransmitted"
716 */
717 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
718 {
719 return (tp->packets_out - tp->left_out + tp->retrans_out);
720 }
721
722 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
723 * The exception is rate halving phase, when cwnd is decreasing towards
724 * ssthresh.
725 */
726 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
727 {
728 const struct tcp_sock *tp = tcp_sk(sk);
729 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
730 return tp->snd_ssthresh;
731 else
732 return max(tp->snd_ssthresh,
733 ((tp->snd_cwnd >> 1) +
734 (tp->snd_cwnd >> 2)));
735 }
736
737 static inline void tcp_sync_left_out(struct tcp_sock *tp)
738 {
739 BUG_ON(tp->sacked_out + tp->lost_out > tp->packets_out);
740 tp->left_out = tp->sacked_out + tp->lost_out;
741 }
742
743 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
744 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
745
746 /* Slow start with delack produces 3 packets of burst, so that
747 * it is safe "de facto".
748 */
749 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
750 {
751 return 3;
752 }
753
754 /* RFC2861 Check whether we are limited by application or congestion window
755 * This is the inverse of cwnd check in tcp_tso_should_defer
756 */
757 static inline int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight)
758 {
759 const struct tcp_sock *tp = tcp_sk(sk);
760 u32 left;
761
762 if (in_flight >= tp->snd_cwnd)
763 return 1;
764
765 if (!sk_can_gso(sk))
766 return 0;
767
768 left = tp->snd_cwnd - in_flight;
769 if (sysctl_tcp_tso_win_divisor)
770 return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd;
771 else
772 return left <= tcp_max_burst(tp);
773 }
774
775 static inline void tcp_minshall_update(struct tcp_sock *tp, int mss,
776 const struct sk_buff *skb)
777 {
778 if (skb->len < mss)
779 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
780 }
781
782 static inline void tcp_check_probe_timer(struct sock *sk)
783 {
784 struct tcp_sock *tp = tcp_sk(sk);
785 const struct inet_connection_sock *icsk = inet_csk(sk);
786
787 if (!tp->packets_out && !icsk->icsk_pending)
788 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
789 icsk->icsk_rto, TCP_RTO_MAX);
790 }
791
792 static inline void tcp_push_pending_frames(struct sock *sk)
793 {
794 struct tcp_sock *tp = tcp_sk(sk);
795
796 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
797 }
798
799 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
800 {
801 tp->snd_wl1 = seq;
802 }
803
804 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
805 {
806 tp->snd_wl1 = seq;
807 }
808
809 /*
810 * Calculate(/check) TCP checksum
811 */
812 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
813 __be32 daddr, __wsum base)
814 {
815 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
816 }
817
818 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
819 {
820 return __skb_checksum_complete(skb);
821 }
822
823 static inline int tcp_checksum_complete(struct sk_buff *skb)
824 {
825 return !skb_csum_unnecessary(skb) &&
826 __tcp_checksum_complete(skb);
827 }
828
829 /* Prequeue for VJ style copy to user, combined with checksumming. */
830
831 static inline void tcp_prequeue_init(struct tcp_sock *tp)
832 {
833 tp->ucopy.task = NULL;
834 tp->ucopy.len = 0;
835 tp->ucopy.memory = 0;
836 skb_queue_head_init(&tp->ucopy.prequeue);
837 #ifdef CONFIG_NET_DMA
838 tp->ucopy.dma_chan = NULL;
839 tp->ucopy.wakeup = 0;
840 tp->ucopy.pinned_list = NULL;
841 tp->ucopy.dma_cookie = 0;
842 #endif
843 }
844
845 /* Packet is added to VJ-style prequeue for processing in process
846 * context, if a reader task is waiting. Apparently, this exciting
847 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
848 * failed somewhere. Latency? Burstiness? Well, at least now we will
849 * see, why it failed. 8)8) --ANK
850 *
851 * NOTE: is this not too big to inline?
852 */
853 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
854 {
855 struct tcp_sock *tp = tcp_sk(sk);
856
857 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
858 __skb_queue_tail(&tp->ucopy.prequeue, skb);
859 tp->ucopy.memory += skb->truesize;
860 if (tp->ucopy.memory > sk->sk_rcvbuf) {
861 struct sk_buff *skb1;
862
863 BUG_ON(sock_owned_by_user(sk));
864
865 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
866 sk->sk_backlog_rcv(sk, skb1);
867 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
868 }
869
870 tp->ucopy.memory = 0;
871 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
872 wake_up_interruptible(sk->sk_sleep);
873 if (!inet_csk_ack_scheduled(sk))
874 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
875 (3 * TCP_RTO_MIN) / 4,
876 TCP_RTO_MAX);
877 }
878 return 1;
879 }
880 return 0;
881 }
882
883
884 #undef STATE_TRACE
885
886 #ifdef STATE_TRACE
887 static const char *statename[]={
888 "Unused","Established","Syn Sent","Syn Recv",
889 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
890 "Close Wait","Last ACK","Listen","Closing"
891 };
892 #endif
893
894 static inline void tcp_set_state(struct sock *sk, int state)
895 {
896 int oldstate = sk->sk_state;
897
898 switch (state) {
899 case TCP_ESTABLISHED:
900 if (oldstate != TCP_ESTABLISHED)
901 TCP_INC_STATS(TCP_MIB_CURRESTAB);
902 break;
903
904 case TCP_CLOSE:
905 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
906 TCP_INC_STATS(TCP_MIB_ESTABRESETS);
907
908 sk->sk_prot->unhash(sk);
909 if (inet_csk(sk)->icsk_bind_hash &&
910 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
911 inet_put_port(&tcp_hashinfo, sk);
912 /* fall through */
913 default:
914 if (oldstate==TCP_ESTABLISHED)
915 TCP_DEC_STATS(TCP_MIB_CURRESTAB);
916 }
917
918 /* Change state AFTER socket is unhashed to avoid closed
919 * socket sitting in hash tables.
920 */
921 sk->sk_state = state;
922
923 #ifdef STATE_TRACE
924 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]);
925 #endif
926 }
927
928 extern void tcp_done(struct sock *sk);
929
930 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
931 {
932 rx_opt->dsack = 0;
933 rx_opt->eff_sacks = 0;
934 rx_opt->num_sacks = 0;
935 }
936
937 /* Determine a window scaling and initial window to offer. */
938 extern void tcp_select_initial_window(int __space, __u32 mss,
939 __u32 *rcv_wnd, __u32 *window_clamp,
940 int wscale_ok, __u8 *rcv_wscale);
941
942 static inline int tcp_win_from_space(int space)
943 {
944 return sysctl_tcp_adv_win_scale<=0 ?
945 (space>>(-sysctl_tcp_adv_win_scale)) :
946 space - (space>>sysctl_tcp_adv_win_scale);
947 }
948
949 /* Note: caller must be prepared to deal with negative returns */
950 static inline int tcp_space(const struct sock *sk)
951 {
952 return tcp_win_from_space(sk->sk_rcvbuf -
953 atomic_read(&sk->sk_rmem_alloc));
954 }
955
956 static inline int tcp_full_space(const struct sock *sk)
957 {
958 return tcp_win_from_space(sk->sk_rcvbuf);
959 }
960
961 static inline void tcp_openreq_init(struct request_sock *req,
962 struct tcp_options_received *rx_opt,
963 struct sk_buff *skb)
964 {
965 struct inet_request_sock *ireq = inet_rsk(req);
966
967 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
968 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
969 req->mss = rx_opt->mss_clamp;
970 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
971 ireq->tstamp_ok = rx_opt->tstamp_ok;
972 ireq->sack_ok = rx_opt->sack_ok;
973 ireq->snd_wscale = rx_opt->snd_wscale;
974 ireq->wscale_ok = rx_opt->wscale_ok;
975 ireq->acked = 0;
976 ireq->ecn_ok = 0;
977 ireq->rmt_port = tcp_hdr(skb)->source;
978 }
979
980 extern void tcp_enter_memory_pressure(void);
981
982 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
983 {
984 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
985 }
986
987 static inline int keepalive_time_when(const struct tcp_sock *tp)
988 {
989 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
990 }
991
992 static inline int tcp_fin_time(const struct sock *sk)
993 {
994 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
995 const int rto = inet_csk(sk)->icsk_rto;
996
997 if (fin_timeout < (rto << 2) - (rto >> 1))
998 fin_timeout = (rto << 2) - (rto >> 1);
999
1000 return fin_timeout;
1001 }
1002
1003 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1004 {
1005 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1006 return 0;
1007 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1008 return 0;
1009
1010 /* RST segments are not recommended to carry timestamp,
1011 and, if they do, it is recommended to ignore PAWS because
1012 "their cleanup function should take precedence over timestamps."
1013 Certainly, it is mistake. It is necessary to understand the reasons
1014 of this constraint to relax it: if peer reboots, clock may go
1015 out-of-sync and half-open connections will not be reset.
1016 Actually, the problem would be not existing if all
1017 the implementations followed draft about maintaining clock
1018 via reboots. Linux-2.2 DOES NOT!
1019
1020 However, we can relax time bounds for RST segments to MSL.
1021 */
1022 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1023 return 0;
1024 return 1;
1025 }
1026
1027 #define TCP_CHECK_TIMER(sk) do { } while (0)
1028
1029 static inline void tcp_mib_init(void)
1030 {
1031 /* See RFC 2012 */
1032 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1033 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1034 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1035 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
1036 }
1037
1038 /*from STCP */
1039 static inline void clear_all_retrans_hints(struct tcp_sock *tp){
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 tp->fastpath_skb_hint = NULL;
1045 }
1046
1047 /* MD5 Signature */
1048 struct crypto_hash;
1049
1050 /* - key database */
1051 struct tcp_md5sig_key {
1052 u8 *key;
1053 u8 keylen;
1054 };
1055
1056 struct tcp4_md5sig_key {
1057 u8 *key;
1058 u16 keylen;
1059 __be32 addr;
1060 };
1061
1062 struct tcp6_md5sig_key {
1063 u8 *key;
1064 u16 keylen;
1065 #if 0
1066 u32 scope_id; /* XXX */
1067 #endif
1068 struct in6_addr addr;
1069 };
1070
1071 /* - sock block */
1072 struct tcp_md5sig_info {
1073 struct tcp4_md5sig_key *keys4;
1074 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1075 struct tcp6_md5sig_key *keys6;
1076 u32 entries6;
1077 u32 alloced6;
1078 #endif
1079 u32 entries4;
1080 u32 alloced4;
1081 };
1082
1083 /* - pseudo header */
1084 struct tcp4_pseudohdr {
1085 __be32 saddr;
1086 __be32 daddr;
1087 __u8 pad;
1088 __u8 protocol;
1089 __be16 len;
1090 };
1091
1092 struct tcp6_pseudohdr {
1093 struct in6_addr saddr;
1094 struct in6_addr daddr;
1095 __be32 len;
1096 __be32 protocol; /* including padding */
1097 };
1098
1099 union tcp_md5sum_block {
1100 struct tcp4_pseudohdr ip4;
1101 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1102 struct tcp6_pseudohdr ip6;
1103 #endif
1104 };
1105
1106 /* - pool: digest algorithm, hash description and scratch buffer */
1107 struct tcp_md5sig_pool {
1108 struct hash_desc md5_desc;
1109 union tcp_md5sum_block md5_blk;
1110 };
1111
1112 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1113
1114 /* - functions */
1115 extern int tcp_v4_calc_md5_hash(char *md5_hash,
1116 struct tcp_md5sig_key *key,
1117 struct sock *sk,
1118 struct dst_entry *dst,
1119 struct request_sock *req,
1120 struct tcphdr *th,
1121 int protocol, int tcplen);
1122 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1123 struct sock *addr_sk);
1124
1125 extern int tcp_v4_md5_do_add(struct sock *sk,
1126 __be32 addr,
1127 u8 *newkey,
1128 u8 newkeylen);
1129
1130 extern int tcp_v4_md5_do_del(struct sock *sk,
1131 __be32 addr);
1132
1133 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1134 extern void tcp_free_md5sig_pool(void);
1135
1136 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1137 extern void __tcp_put_md5sig_pool(void);
1138
1139 static inline
1140 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1141 {
1142 int cpu = get_cpu();
1143 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1144 if (!ret)
1145 put_cpu();
1146 return ret;
1147 }
1148
1149 static inline void tcp_put_md5sig_pool(void)
1150 {
1151 __tcp_put_md5sig_pool();
1152 put_cpu();
1153 }
1154
1155 /* write queue abstraction */
1156 static inline void tcp_write_queue_purge(struct sock *sk)
1157 {
1158 struct sk_buff *skb;
1159
1160 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1161 sk_stream_free_skb(sk, skb);
1162 sk_stream_mem_reclaim(sk);
1163 }
1164
1165 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1166 {
1167 struct sk_buff *skb = sk->sk_write_queue.next;
1168 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1169 return NULL;
1170 return skb;
1171 }
1172
1173 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1174 {
1175 struct sk_buff *skb = sk->sk_write_queue.prev;
1176 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1177 return NULL;
1178 return skb;
1179 }
1180
1181 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1182 {
1183 return skb->next;
1184 }
1185
1186 #define tcp_for_write_queue(skb, sk) \
1187 for (skb = (sk)->sk_write_queue.next; \
1188 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1189 skb = skb->next)
1190
1191 #define tcp_for_write_queue_from(skb, sk) \
1192 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\
1193 skb = skb->next)
1194
1195 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1196 {
1197 return sk->sk_send_head;
1198 }
1199
1200 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1201 {
1202 struct tcp_sock *tp = tcp_sk(sk);
1203
1204 sk->sk_send_head = skb->next;
1205 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
1206 sk->sk_send_head = NULL;
1207 /* Don't override Nagle indefinately with F-RTO */
1208 if (tp->frto_counter == 2)
1209 tp->frto_counter = 3;
1210 }
1211
1212 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1213 {
1214 if (sk->sk_send_head == skb_unlinked)
1215 sk->sk_send_head = NULL;
1216 }
1217
1218 static inline void tcp_init_send_head(struct sock *sk)
1219 {
1220 sk->sk_send_head = NULL;
1221 }
1222
1223 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1224 {
1225 __skb_queue_tail(&sk->sk_write_queue, skb);
1226 }
1227
1228 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1229 {
1230 __tcp_add_write_queue_tail(sk, skb);
1231
1232 /* Queue it, remembering where we must start sending. */
1233 if (sk->sk_send_head == NULL)
1234 sk->sk_send_head = skb;
1235 }
1236
1237 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1238 {
1239 __skb_queue_head(&sk->sk_write_queue, skb);
1240 }
1241
1242 /* Insert buff after skb on the write queue of sk. */
1243 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1244 struct sk_buff *buff,
1245 struct sock *sk)
1246 {
1247 __skb_append(skb, buff, &sk->sk_write_queue);
1248 }
1249
1250 /* Insert skb between prev and next on the write queue of sk. */
1251 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1252 struct sk_buff *skb,
1253 struct sock *sk)
1254 {
1255 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
1256 }
1257
1258 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1259 {
1260 __skb_unlink(skb, &sk->sk_write_queue);
1261 }
1262
1263 static inline int tcp_skb_is_last(const struct sock *sk,
1264 const struct sk_buff *skb)
1265 {
1266 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1267 }
1268
1269 static inline int tcp_write_queue_empty(struct sock *sk)
1270 {
1271 return skb_queue_empty(&sk->sk_write_queue);
1272 }
1273
1274 /* /proc */
1275 enum tcp_seq_states {
1276 TCP_SEQ_STATE_LISTENING,
1277 TCP_SEQ_STATE_OPENREQ,
1278 TCP_SEQ_STATE_ESTABLISHED,
1279 TCP_SEQ_STATE_TIME_WAIT,
1280 };
1281
1282 struct tcp_seq_afinfo {
1283 struct module *owner;
1284 char *name;
1285 sa_family_t family;
1286 int (*seq_show) (struct seq_file *m, void *v);
1287 struct file_operations *seq_fops;
1288 };
1289
1290 struct tcp_iter_state {
1291 sa_family_t family;
1292 enum tcp_seq_states state;
1293 struct sock *syn_wait_sk;
1294 int bucket, sbucket, num, uid;
1295 struct seq_operations seq_ops;
1296 };
1297
1298 extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo);
1299 extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo);
1300
1301 extern struct request_sock_ops tcp_request_sock_ops;
1302
1303 extern int tcp_v4_destroy_sock(struct sock *sk);
1304
1305 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1306 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1307
1308 #ifdef CONFIG_PROC_FS
1309 extern int tcp4_proc_init(void);
1310 extern void tcp4_proc_exit(void);
1311 #endif
1312
1313 /* TCP af-specific functions */
1314 struct tcp_sock_af_ops {
1315 #ifdef CONFIG_TCP_MD5SIG
1316 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1317 struct sock *addr_sk);
1318 int (*calc_md5_hash) (char *location,
1319 struct tcp_md5sig_key *md5,
1320 struct sock *sk,
1321 struct dst_entry *dst,
1322 struct request_sock *req,
1323 struct tcphdr *th,
1324 int protocol, int len);
1325 int (*md5_add) (struct sock *sk,
1326 struct sock *addr_sk,
1327 u8 *newkey,
1328 u8 len);
1329 int (*md5_parse) (struct sock *sk,
1330 char __user *optval,
1331 int optlen);
1332 #endif
1333 };
1334
1335 struct tcp_request_sock_ops {
1336 #ifdef CONFIG_TCP_MD5SIG
1337 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1338 struct request_sock *req);
1339 #endif
1340 };
1341
1342 extern void tcp_v4_init(struct net_proto_family *ops);
1343 extern void tcp_init(void);
1344
1345 #endif /* _TCP_H */
Linux kernel - Deliverables
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