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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shaggy...
[deliverable/linux.git] / include / net / tcp.h
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Definitions for the TCP module.
7 *
8 * Version: @(#)tcp.h 1.0.5 05/23/93
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
17 */
18 #ifndef _TCP_H
19 #define _TCP_H
20
21 #define TCP_DEBUG 1
22 #define FASTRETRANS_DEBUG 1
23
24 #include <linux/list.h>
25 #include <linux/tcp.h>
26 #include <linux/slab.h>
27 #include <linux/cache.h>
28 #include <linux/percpu.h>
29 #include <linux/skbuff.h>
30 #include <linux/dmaengine.h>
31 #include <linux/crypto.h>
32 #include <linux/cryptohash.h>
33
34 #include <net/inet_connection_sock.h>
35 #include <net/inet_timewait_sock.h>
36 #include <net/inet_hashtables.h>
37 #include <net/checksum.h>
38 #include <net/request_sock.h>
39 #include <net/sock.h>
40 #include <net/snmp.h>
41 #include <net/ip.h>
42 #include <net/tcp_states.h>
43 #include <net/inet_ecn.h>
44
45 #include <linux/seq_file.h>
46
47 extern struct inet_hashinfo tcp_hashinfo;
48
49 extern atomic_t tcp_orphan_count;
50 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
51
52 #define MAX_TCP_HEADER (128 + MAX_HEADER)
53
54 /*
55 * Never offer a window over 32767 without using window scaling. Some
56 * poor stacks do signed 16bit maths!
57 */
58 #define MAX_TCP_WINDOW 32767U
59
60 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
61 #define TCP_MIN_MSS 88U
62
63 /* Minimal RCV_MSS. */
64 #define TCP_MIN_RCVMSS 536U
65
66 /* The least MTU to use for probing */
67 #define TCP_BASE_MSS 512
68
69 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
70 #define TCP_FASTRETRANS_THRESH 3
71
72 /* Maximal reordering. */
73 #define TCP_MAX_REORDERING 127
74
75 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
76 #define TCP_MAX_QUICKACKS 16U
77
78 /* urg_data states */
79 #define TCP_URG_VALID 0x0100
80 #define TCP_URG_NOTYET 0x0200
81 #define TCP_URG_READ 0x0400
82
83 #define TCP_RETR1 3 /*
84 * This is how many retries it does before it
85 * tries to figure out if the gateway is
86 * down. Minimal RFC value is 3; it corresponds
87 * to ~3sec-8min depending on RTO.
88 */
89
90 #define TCP_RETR2 15 /*
91 * This should take at least
92 * 90 minutes to time out.
93 * RFC1122 says that the limit is 100 sec.
94 * 15 is ~13-30min depending on RTO.
95 */
96
97 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
98 * connection: ~180sec is RFC minimum */
99
100 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
101 * connection: ~180sec is RFC minimum */
102
103
104 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
105 * socket. 7 is ~50sec-16min.
106 */
107
108
109 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
110 * state, about 60 seconds */
111 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
112 /* BSD style FIN_WAIT2 deadlock breaker.
113 * It used to be 3min, new value is 60sec,
114 * to combine FIN-WAIT-2 timeout with
115 * TIME-WAIT timer.
116 */
117
118 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
119 #if HZ >= 100
120 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
121 #define TCP_ATO_MIN ((unsigned)(HZ/25))
122 #else
123 #define TCP_DELACK_MIN 4U
124 #define TCP_ATO_MIN 4U
125 #endif
126 #define TCP_RTO_MAX ((unsigned)(120*HZ))
127 #define TCP_RTO_MIN ((unsigned)(HZ/5))
128 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
129
130 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
131 * for local resources.
132 */
133
134 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
135 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
136 #define TCP_KEEPALIVE_INTVL (75*HZ)
137
138 #define MAX_TCP_KEEPIDLE 32767
139 #define MAX_TCP_KEEPINTVL 32767
140 #define MAX_TCP_KEEPCNT 127
141 #define MAX_TCP_SYNCNT 127
142
143 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
144
145 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
146 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
147 * after this time. It should be equal
148 * (or greater than) TCP_TIMEWAIT_LEN
149 * to provide reliability equal to one
150 * provided by timewait state.
151 */
152 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
153 * timestamps. It must be less than
154 * minimal timewait lifetime.
155 */
156 /*
157 * TCP option
158 */
159
160 #define TCPOPT_NOP 1 /* Padding */
161 #define TCPOPT_EOL 0 /* End of options */
162 #define TCPOPT_MSS 2 /* Segment size negotiating */
163 #define TCPOPT_WINDOW 3 /* Window scaling */
164 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
165 #define TCPOPT_SACK 5 /* SACK Block */
166 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
167 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
168
169 /*
170 * TCP option lengths
171 */
172
173 #define TCPOLEN_MSS 4
174 #define TCPOLEN_WINDOW 3
175 #define TCPOLEN_SACK_PERM 2
176 #define TCPOLEN_TIMESTAMP 10
177 #define TCPOLEN_MD5SIG 18
178
179 /* But this is what stacks really send out. */
180 #define TCPOLEN_TSTAMP_ALIGNED 12
181 #define TCPOLEN_WSCALE_ALIGNED 4
182 #define TCPOLEN_SACKPERM_ALIGNED 4
183 #define TCPOLEN_SACK_BASE 2
184 #define TCPOLEN_SACK_BASE_ALIGNED 4
185 #define TCPOLEN_SACK_PERBLOCK 8
186 #define TCPOLEN_MD5SIG_ALIGNED 20
187
188 /* Flags in tp->nonagle */
189 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
190 #define TCP_NAGLE_CORK 2 /* Socket is corked */
191 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
192
193 extern struct inet_timewait_death_row tcp_death_row;
194
195 /* sysctl variables for tcp */
196 extern int sysctl_tcp_timestamps;
197 extern int sysctl_tcp_window_scaling;
198 extern int sysctl_tcp_sack;
199 extern int sysctl_tcp_fin_timeout;
200 extern int sysctl_tcp_keepalive_time;
201 extern int sysctl_tcp_keepalive_probes;
202 extern int sysctl_tcp_keepalive_intvl;
203 extern int sysctl_tcp_syn_retries;
204 extern int sysctl_tcp_synack_retries;
205 extern int sysctl_tcp_retries1;
206 extern int sysctl_tcp_retries2;
207 extern int sysctl_tcp_orphan_retries;
208 extern int sysctl_tcp_syncookies;
209 extern int sysctl_tcp_retrans_collapse;
210 extern int sysctl_tcp_stdurg;
211 extern int sysctl_tcp_rfc1337;
212 extern int sysctl_tcp_abort_on_overflow;
213 extern int sysctl_tcp_max_orphans;
214 extern int sysctl_tcp_fack;
215 extern int sysctl_tcp_reordering;
216 extern int sysctl_tcp_ecn;
217 extern int sysctl_tcp_dsack;
218 extern int sysctl_tcp_mem[3];
219 extern int sysctl_tcp_wmem[3];
220 extern int sysctl_tcp_rmem[3];
221 extern int sysctl_tcp_app_win;
222 extern int sysctl_tcp_adv_win_scale;
223 extern int sysctl_tcp_tw_reuse;
224 extern int sysctl_tcp_frto;
225 extern int sysctl_tcp_frto_response;
226 extern int sysctl_tcp_low_latency;
227 extern int sysctl_tcp_dma_copybreak;
228 extern int sysctl_tcp_nometrics_save;
229 extern int sysctl_tcp_moderate_rcvbuf;
230 extern int sysctl_tcp_tso_win_divisor;
231 extern int sysctl_tcp_abc;
232 extern int sysctl_tcp_mtu_probing;
233 extern int sysctl_tcp_base_mss;
234 extern int sysctl_tcp_workaround_signed_windows;
235 extern int sysctl_tcp_slow_start_after_idle;
236 extern int sysctl_tcp_max_ssthresh;
237
238 extern atomic_t tcp_memory_allocated;
239 extern atomic_t tcp_sockets_allocated;
240 extern int tcp_memory_pressure;
241
242 /*
243 * The next routines deal with comparing 32 bit unsigned ints
244 * and worry about wraparound (automatic with unsigned arithmetic).
245 */
246
247 static inline int before(__u32 seq1, __u32 seq2)
248 {
249 return (__s32)(seq1-seq2) < 0;
250 }
251 #define after(seq2, seq1) before(seq1, seq2)
252
253 /* is s2<=s1<=s3 ? */
254 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
255 {
256 return seq3 - seq2 >= seq1 - seq2;
257 }
258
259 static inline int tcp_too_many_orphans(struct sock *sk, int num)
260 {
261 return (num > sysctl_tcp_max_orphans) ||
262 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
263 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
264 }
265
266 extern struct proto tcp_prot;
267
268 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
269 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
270 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
271 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
272 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
273 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
274 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
275
276 extern void tcp_v4_err(struct sk_buff *skb, u32);
277
278 extern void tcp_shutdown (struct sock *sk, int how);
279
280 extern int tcp_v4_rcv(struct sk_buff *skb);
281
282 extern int tcp_v4_remember_stamp(struct sock *sk);
283
284 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
285
286 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
287 struct msghdr *msg, size_t size);
288 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
289
290 extern int tcp_ioctl(struct sock *sk,
291 int cmd,
292 unsigned long arg);
293
294 extern int tcp_rcv_state_process(struct sock *sk,
295 struct sk_buff *skb,
296 struct tcphdr *th,
297 unsigned len);
298
299 extern int tcp_rcv_established(struct sock *sk,
300 struct sk_buff *skb,
301 struct tcphdr *th,
302 unsigned len);
303
304 extern void tcp_rcv_space_adjust(struct sock *sk);
305
306 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
307
308 extern int tcp_twsk_unique(struct sock *sk,
309 struct sock *sktw, void *twp);
310
311 extern void tcp_twsk_destructor(struct sock *sk);
312
313 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
314 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
315
316 static inline void tcp_dec_quickack_mode(struct sock *sk,
317 const unsigned int pkts)
318 {
319 struct inet_connection_sock *icsk = inet_csk(sk);
320
321 if (icsk->icsk_ack.quick) {
322 if (pkts >= icsk->icsk_ack.quick) {
323 icsk->icsk_ack.quick = 0;
324 /* Leaving quickack mode we deflate ATO. */
325 icsk->icsk_ack.ato = TCP_ATO_MIN;
326 } else
327 icsk->icsk_ack.quick -= pkts;
328 }
329 }
330
331 extern void tcp_enter_quickack_mode(struct sock *sk);
332
333 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
334 {
335 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
336 }
337
338 #define TCP_ECN_OK 1
339 #define TCP_ECN_QUEUE_CWR 2
340 #define TCP_ECN_DEMAND_CWR 4
341
342 static __inline__ void
343 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
344 {
345 if (sysctl_tcp_ecn && th->ece && th->cwr)
346 inet_rsk(req)->ecn_ok = 1;
347 }
348
349 enum tcp_tw_status
350 {
351 TCP_TW_SUCCESS = 0,
352 TCP_TW_RST = 1,
353 TCP_TW_ACK = 2,
354 TCP_TW_SYN = 3
355 };
356
357
358 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
359 struct sk_buff *skb,
360 const struct tcphdr *th);
361
362 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
363 struct request_sock *req,
364 struct request_sock **prev);
365 extern int tcp_child_process(struct sock *parent,
366 struct sock *child,
367 struct sk_buff *skb);
368 extern int tcp_use_frto(struct sock *sk);
369 extern void tcp_enter_frto(struct sock *sk);
370 extern void tcp_enter_loss(struct sock *sk, int how);
371 extern void tcp_clear_retrans(struct tcp_sock *tp);
372 extern void tcp_update_metrics(struct sock *sk);
373
374 extern void tcp_close(struct sock *sk,
375 long timeout);
376 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
377
378 extern int tcp_getsockopt(struct sock *sk, int level,
379 int optname,
380 char __user *optval,
381 int __user *optlen);
382 extern int tcp_setsockopt(struct sock *sk, int level,
383 int optname, char __user *optval,
384 int optlen);
385 extern int compat_tcp_getsockopt(struct sock *sk,
386 int level, int optname,
387 char __user *optval, int __user *optlen);
388 extern int compat_tcp_setsockopt(struct sock *sk,
389 int level, int optname,
390 char __user *optval, int optlen);
391 extern void tcp_set_keepalive(struct sock *sk, int val);
392 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
393 struct msghdr *msg,
394 size_t len, int nonblock,
395 int flags, int *addr_len);
396
397 extern void tcp_parse_options(struct sk_buff *skb,
398 struct tcp_options_received *opt_rx,
399 int estab);
400
401 /*
402 * TCP v4 functions exported for the inet6 API
403 */
404
405 extern void tcp_v4_send_check(struct sock *sk, int len,
406 struct sk_buff *skb);
407
408 extern int tcp_v4_conn_request(struct sock *sk,
409 struct sk_buff *skb);
410
411 extern struct sock * tcp_create_openreq_child(struct sock *sk,
412 struct request_sock *req,
413 struct sk_buff *skb);
414
415 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
416 struct sk_buff *skb,
417 struct request_sock *req,
418 struct dst_entry *dst);
419
420 extern int tcp_v4_do_rcv(struct sock *sk,
421 struct sk_buff *skb);
422
423 extern int tcp_v4_connect(struct sock *sk,
424 struct sockaddr *uaddr,
425 int addr_len);
426
427 extern int tcp_connect(struct sock *sk);
428
429 extern struct sk_buff * tcp_make_synack(struct sock *sk,
430 struct dst_entry *dst,
431 struct request_sock *req);
432
433 extern int tcp_disconnect(struct sock *sk, int flags);
434
435
436 /* From syncookies.c */
437 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
438 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
439 struct ip_options *opt);
440 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
441 __u16 *mss);
442
443 extern __u32 cookie_init_timestamp(struct request_sock *req);
444 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
445
446 /* From net/ipv6/syncookies.c */
447 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
448 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
449 __u16 *mss);
450
451 /* tcp_output.c */
452
453 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
454 int nonagle);
455 extern int tcp_may_send_now(struct sock *sk);
456 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
457 extern void tcp_xmit_retransmit_queue(struct sock *);
458 extern void tcp_simple_retransmit(struct sock *);
459 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
460 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
461
462 extern void tcp_send_probe0(struct sock *);
463 extern void tcp_send_partial(struct sock *);
464 extern int tcp_write_wakeup(struct sock *);
465 extern void tcp_send_fin(struct sock *sk);
466 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
467 extern int tcp_send_synack(struct sock *);
468 extern void tcp_push_one(struct sock *, unsigned int mss_now);
469 extern void tcp_send_ack(struct sock *sk);
470 extern void tcp_send_delayed_ack(struct sock *sk);
471
472 /* tcp_input.c */
473 extern void tcp_cwnd_application_limited(struct sock *sk);
474
475 /* tcp_timer.c */
476 extern void tcp_init_xmit_timers(struct sock *);
477 static inline void tcp_clear_xmit_timers(struct sock *sk)
478 {
479 inet_csk_clear_xmit_timers(sk);
480 }
481
482 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
483 extern unsigned int tcp_current_mss(struct sock *sk, int large);
484
485 /* tcp.c */
486 extern void tcp_get_info(struct sock *, struct tcp_info *);
487
488 /* Read 'sendfile()'-style from a TCP socket */
489 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
490 unsigned int, size_t);
491 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
492 sk_read_actor_t recv_actor);
493
494 extern void tcp_initialize_rcv_mss(struct sock *sk);
495
496 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
497 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
498 extern void tcp_mtup_init(struct sock *sk);
499
500 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
501 {
502 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
503 ntohl(TCP_FLAG_ACK) |
504 snd_wnd);
505 }
506
507 static inline void tcp_fast_path_on(struct tcp_sock *tp)
508 {
509 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
510 }
511
512 static inline void tcp_fast_path_check(struct sock *sk)
513 {
514 struct tcp_sock *tp = tcp_sk(sk);
515
516 if (skb_queue_empty(&tp->out_of_order_queue) &&
517 tp->rcv_wnd &&
518 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
519 !tp->urg_data)
520 tcp_fast_path_on(tp);
521 }
522
523 /* Compute the actual receive window we are currently advertising.
524 * Rcv_nxt can be after the window if our peer push more data
525 * than the offered window.
526 */
527 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
528 {
529 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
530
531 if (win < 0)
532 win = 0;
533 return (u32) win;
534 }
535
536 /* Choose a new window, without checks for shrinking, and without
537 * scaling applied to the result. The caller does these things
538 * if necessary. This is a "raw" window selection.
539 */
540 extern u32 __tcp_select_window(struct sock *sk);
541
542 /* TCP timestamps are only 32-bits, this causes a slight
543 * complication on 64-bit systems since we store a snapshot
544 * of jiffies in the buffer control blocks below. We decided
545 * to use only the low 32-bits of jiffies and hide the ugly
546 * casts with the following macro.
547 */
548 #define tcp_time_stamp ((__u32)(jiffies))
549
550 /* This is what the send packet queuing engine uses to pass
551 * TCP per-packet control information to the transmission
552 * code. We also store the host-order sequence numbers in
553 * here too. This is 36 bytes on 32-bit architectures,
554 * 40 bytes on 64-bit machines, if this grows please adjust
555 * skbuff.h:skbuff->cb[xxx] size appropriately.
556 */
557 struct tcp_skb_cb {
558 union {
559 struct inet_skb_parm h4;
560 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
561 struct inet6_skb_parm h6;
562 #endif
563 } header; /* For incoming frames */
564 __u32 seq; /* Starting sequence number */
565 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
566 __u32 when; /* used to compute rtt's */
567 __u8 flags; /* TCP header flags. */
568
569 /* NOTE: These must match up to the flags byte in a
570 * real TCP header.
571 */
572 #define TCPCB_FLAG_FIN 0x01
573 #define TCPCB_FLAG_SYN 0x02
574 #define TCPCB_FLAG_RST 0x04
575 #define TCPCB_FLAG_PSH 0x08
576 #define TCPCB_FLAG_ACK 0x10
577 #define TCPCB_FLAG_URG 0x20
578 #define TCPCB_FLAG_ECE 0x40
579 #define TCPCB_FLAG_CWR 0x80
580
581 __u8 sacked; /* State flags for SACK/FACK. */
582 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
583 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
584 #define TCPCB_LOST 0x04 /* SKB is lost */
585 #define TCPCB_TAGBITS 0x07 /* All tag bits */
586
587 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
588 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
589
590 __u16 urg_ptr; /* Valid w/URG flags is set. */
591 __u32 ack_seq; /* Sequence number ACK'd */
592 };
593
594 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
595
596 /* Due to TSO, an SKB can be composed of multiple actual
597 * packets. To keep these tracked properly, we use this.
598 */
599 static inline int tcp_skb_pcount(const struct sk_buff *skb)
600 {
601 return skb_shinfo(skb)->gso_segs;
602 }
603
604 /* This is valid iff tcp_skb_pcount() > 1. */
605 static inline int tcp_skb_mss(const struct sk_buff *skb)
606 {
607 return skb_shinfo(skb)->gso_size;
608 }
609
610 static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
611 {
612 if (*count) {
613 *count -= decr;
614 if ((int)*count < 0)
615 *count = 0;
616 }
617 }
618
619 static inline void tcp_dec_pcount_approx(__u32 *count,
620 const struct sk_buff *skb)
621 {
622 tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
623 }
624
625 /* Events passed to congestion control interface */
626 enum tcp_ca_event {
627 CA_EVENT_TX_START, /* first transmit when no packets in flight */
628 CA_EVENT_CWND_RESTART, /* congestion window restart */
629 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
630 CA_EVENT_FRTO, /* fast recovery timeout */
631 CA_EVENT_LOSS, /* loss timeout */
632 CA_EVENT_FAST_ACK, /* in sequence ack */
633 CA_EVENT_SLOW_ACK, /* other ack */
634 };
635
636 /*
637 * Interface for adding new TCP congestion control handlers
638 */
639 #define TCP_CA_NAME_MAX 16
640 #define TCP_CA_MAX 128
641 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
642
643 #define TCP_CONG_NON_RESTRICTED 0x1
644 #define TCP_CONG_RTT_STAMP 0x2
645
646 struct tcp_congestion_ops {
647 struct list_head list;
648 unsigned long flags;
649
650 /* initialize private data (optional) */
651 void (*init)(struct sock *sk);
652 /* cleanup private data (optional) */
653 void (*release)(struct sock *sk);
654
655 /* return slow start threshold (required) */
656 u32 (*ssthresh)(struct sock *sk);
657 /* lower bound for congestion window (optional) */
658 u32 (*min_cwnd)(const struct sock *sk);
659 /* do new cwnd calculation (required) */
660 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
661 /* call before changing ca_state (optional) */
662 void (*set_state)(struct sock *sk, u8 new_state);
663 /* call when cwnd event occurs (optional) */
664 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
665 /* new value of cwnd after loss (optional) */
666 u32 (*undo_cwnd)(struct sock *sk);
667 /* hook for packet ack accounting (optional) */
668 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
669 /* get info for inet_diag (optional) */
670 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
671
672 char name[TCP_CA_NAME_MAX];
673 struct module *owner;
674 };
675
676 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
677 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
678
679 extern void tcp_init_congestion_control(struct sock *sk);
680 extern void tcp_cleanup_congestion_control(struct sock *sk);
681 extern int tcp_set_default_congestion_control(const char *name);
682 extern void tcp_get_default_congestion_control(char *name);
683 extern void tcp_get_available_congestion_control(char *buf, size_t len);
684 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
685 extern int tcp_set_allowed_congestion_control(char *allowed);
686 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
687 extern void tcp_slow_start(struct tcp_sock *tp);
688
689 extern struct tcp_congestion_ops tcp_init_congestion_ops;
690 extern u32 tcp_reno_ssthresh(struct sock *sk);
691 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
692 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
693 extern struct tcp_congestion_ops tcp_reno;
694
695 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
696 {
697 struct inet_connection_sock *icsk = inet_csk(sk);
698
699 if (icsk->icsk_ca_ops->set_state)
700 icsk->icsk_ca_ops->set_state(sk, ca_state);
701 icsk->icsk_ca_state = ca_state;
702 }
703
704 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
705 {
706 const struct inet_connection_sock *icsk = inet_csk(sk);
707
708 if (icsk->icsk_ca_ops->cwnd_event)
709 icsk->icsk_ca_ops->cwnd_event(sk, event);
710 }
711
712 /* These functions determine how the current flow behaves in respect of SACK
713 * handling. SACK is negotiated with the peer, and therefore it can vary
714 * between different flows.
715 *
716 * tcp_is_sack - SACK enabled
717 * tcp_is_reno - No SACK
718 * tcp_is_fack - FACK enabled, implies SACK enabled
719 */
720 static inline int tcp_is_sack(const struct tcp_sock *tp)
721 {
722 return tp->rx_opt.sack_ok;
723 }
724
725 static inline int tcp_is_reno(const struct tcp_sock *tp)
726 {
727 return !tcp_is_sack(tp);
728 }
729
730 static inline int tcp_is_fack(const struct tcp_sock *tp)
731 {
732 return tp->rx_opt.sack_ok & 2;
733 }
734
735 static inline void tcp_enable_fack(struct tcp_sock *tp)
736 {
737 tp->rx_opt.sack_ok |= 2;
738 }
739
740 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
741 {
742 return tp->sacked_out + tp->lost_out;
743 }
744
745 /* This determines how many packets are "in the network" to the best
746 * of our knowledge. In many cases it is conservative, but where
747 * detailed information is available from the receiver (via SACK
748 * blocks etc.) we can make more aggressive calculations.
749 *
750 * Use this for decisions involving congestion control, use just
751 * tp->packets_out to determine if the send queue is empty or not.
752 *
753 * Read this equation as:
754 *
755 * "Packets sent once on transmission queue" MINUS
756 * "Packets left network, but not honestly ACKed yet" PLUS
757 * "Packets fast retransmitted"
758 */
759 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
760 {
761 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
762 }
763
764 extern int tcp_limit_reno_sacked(struct tcp_sock *tp);
765
766 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
767 * The exception is rate halving phase, when cwnd is decreasing towards
768 * ssthresh.
769 */
770 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
771 {
772 const struct tcp_sock *tp = tcp_sk(sk);
773 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
774 return tp->snd_ssthresh;
775 else
776 return max(tp->snd_ssthresh,
777 ((tp->snd_cwnd >> 1) +
778 (tp->snd_cwnd >> 2)));
779 }
780
781 /* Use define here intentionally to get WARN_ON location shown at the caller */
782 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
783
784 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
785 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
786
787 /* Slow start with delack produces 3 packets of burst, so that
788 * it is safe "de facto". This will be the default - same as
789 * the default reordering threshold - but if reordering increases,
790 * we must be able to allow cwnd to burst at least this much in order
791 * to not pull it back when holes are filled.
792 */
793 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
794 {
795 return tp->reordering;
796 }
797
798 /* Returns end sequence number of the receiver's advertised window */
799 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
800 {
801 return tp->snd_una + tp->snd_wnd;
802 }
803 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
804
805 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
806 const struct sk_buff *skb)
807 {
808 if (skb->len < mss)
809 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
810 }
811
812 static inline void tcp_check_probe_timer(struct sock *sk)
813 {
814 struct tcp_sock *tp = tcp_sk(sk);
815 const struct inet_connection_sock *icsk = inet_csk(sk);
816
817 if (!tp->packets_out && !icsk->icsk_pending)
818 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
819 icsk->icsk_rto, TCP_RTO_MAX);
820 }
821
822 static inline void tcp_push_pending_frames(struct sock *sk)
823 {
824 struct tcp_sock *tp = tcp_sk(sk);
825
826 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
827 }
828
829 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
830 {
831 tp->snd_wl1 = seq;
832 }
833
834 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
835 {
836 tp->snd_wl1 = seq;
837 }
838
839 /*
840 * Calculate(/check) TCP checksum
841 */
842 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
843 __be32 daddr, __wsum base)
844 {
845 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
846 }
847
848 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
849 {
850 return __skb_checksum_complete(skb);
851 }
852
853 static inline int tcp_checksum_complete(struct sk_buff *skb)
854 {
855 return !skb_csum_unnecessary(skb) &&
856 __tcp_checksum_complete(skb);
857 }
858
859 /* Prequeue for VJ style copy to user, combined with checksumming. */
860
861 static inline void tcp_prequeue_init(struct tcp_sock *tp)
862 {
863 tp->ucopy.task = NULL;
864 tp->ucopy.len = 0;
865 tp->ucopy.memory = 0;
866 skb_queue_head_init(&tp->ucopy.prequeue);
867 #ifdef CONFIG_NET_DMA
868 tp->ucopy.dma_chan = NULL;
869 tp->ucopy.wakeup = 0;
870 tp->ucopy.pinned_list = NULL;
871 tp->ucopy.dma_cookie = 0;
872 #endif
873 }
874
875 /* Packet is added to VJ-style prequeue for processing in process
876 * context, if a reader task is waiting. Apparently, this exciting
877 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
878 * failed somewhere. Latency? Burstiness? Well, at least now we will
879 * see, why it failed. 8)8) --ANK
880 *
881 * NOTE: is this not too big to inline?
882 */
883 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
884 {
885 struct tcp_sock *tp = tcp_sk(sk);
886
887 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
888 __skb_queue_tail(&tp->ucopy.prequeue, skb);
889 tp->ucopy.memory += skb->truesize;
890 if (tp->ucopy.memory > sk->sk_rcvbuf) {
891 struct sk_buff *skb1;
892
893 BUG_ON(sock_owned_by_user(sk));
894
895 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
896 sk->sk_backlog_rcv(sk, skb1);
897 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
898 }
899
900 tp->ucopy.memory = 0;
901 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
902 wake_up_interruptible(sk->sk_sleep);
903 if (!inet_csk_ack_scheduled(sk))
904 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
905 (3 * TCP_RTO_MIN) / 4,
906 TCP_RTO_MAX);
907 }
908 return 1;
909 }
910 return 0;
911 }
912
913
914 #undef STATE_TRACE
915
916 #ifdef STATE_TRACE
917 static const char *statename[]={
918 "Unused","Established","Syn Sent","Syn Recv",
919 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
920 "Close Wait","Last ACK","Listen","Closing"
921 };
922 #endif
923 extern void tcp_set_state(struct sock *sk, int state);
924
925 extern void tcp_done(struct sock *sk);
926
927 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
928 {
929 rx_opt->dsack = 0;
930 rx_opt->eff_sacks = 0;
931 rx_opt->num_sacks = 0;
932 }
933
934 /* Determine a window scaling and initial window to offer. */
935 extern void tcp_select_initial_window(int __space, __u32 mss,
936 __u32 *rcv_wnd, __u32 *window_clamp,
937 int wscale_ok, __u8 *rcv_wscale);
938
939 static inline int tcp_win_from_space(int space)
940 {
941 return sysctl_tcp_adv_win_scale<=0 ?
942 (space>>(-sysctl_tcp_adv_win_scale)) :
943 space - (space>>sysctl_tcp_adv_win_scale);
944 }
945
946 /* Note: caller must be prepared to deal with negative returns */
947 static inline int tcp_space(const struct sock *sk)
948 {
949 return tcp_win_from_space(sk->sk_rcvbuf -
950 atomic_read(&sk->sk_rmem_alloc));
951 }
952
953 static inline int tcp_full_space(const struct sock *sk)
954 {
955 return tcp_win_from_space(sk->sk_rcvbuf);
956 }
957
958 static inline void tcp_openreq_init(struct request_sock *req,
959 struct tcp_options_received *rx_opt,
960 struct sk_buff *skb)
961 {
962 struct inet_request_sock *ireq = inet_rsk(req);
963
964 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
965 req->cookie_ts = 0;
966 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
967 req->mss = rx_opt->mss_clamp;
968 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
969 ireq->tstamp_ok = rx_opt->tstamp_ok;
970 ireq->sack_ok = rx_opt->sack_ok;
971 ireq->snd_wscale = rx_opt->snd_wscale;
972 ireq->wscale_ok = rx_opt->wscale_ok;
973 ireq->acked = 0;
974 ireq->ecn_ok = 0;
975 ireq->rmt_port = tcp_hdr(skb)->source;
976 }
977
978 extern void tcp_enter_memory_pressure(void);
979
980 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
981 {
982 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
983 }
984
985 static inline int keepalive_time_when(const struct tcp_sock *tp)
986 {
987 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
988 }
989
990 static inline int tcp_fin_time(const struct sock *sk)
991 {
992 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
993 const int rto = inet_csk(sk)->icsk_rto;
994
995 if (fin_timeout < (rto << 2) - (rto >> 1))
996 fin_timeout = (rto << 2) - (rto >> 1);
997
998 return fin_timeout;
999 }
1000
1001 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1002 {
1003 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1004 return 0;
1005 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1006 return 0;
1007
1008 /* RST segments are not recommended to carry timestamp,
1009 and, if they do, it is recommended to ignore PAWS because
1010 "their cleanup function should take precedence over timestamps."
1011 Certainly, it is mistake. It is necessary to understand the reasons
1012 of this constraint to relax it: if peer reboots, clock may go
1013 out-of-sync and half-open connections will not be reset.
1014 Actually, the problem would be not existing if all
1015 the implementations followed draft about maintaining clock
1016 via reboots. Linux-2.2 DOES NOT!
1017
1018 However, we can relax time bounds for RST segments to MSL.
1019 */
1020 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1021 return 0;
1022 return 1;
1023 }
1024
1025 #define TCP_CHECK_TIMER(sk) do { } while (0)
1026
1027 static inline void tcp_mib_init(void)
1028 {
1029 /* See RFC 2012 */
1030 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1031 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1032 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1033 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
1034 }
1035
1036 /* from STCP */
1037 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1038 {
1039 tp->lost_skb_hint = NULL;
1040 tp->scoreboard_skb_hint = NULL;
1041 tp->retransmit_skb_hint = NULL;
1042 tp->forward_skb_hint = NULL;
1043 }
1044
1045 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1046 {
1047 tcp_clear_retrans_hints_partial(tp);
1048 }
1049
1050 /* MD5 Signature */
1051 struct crypto_hash;
1052
1053 /* - key database */
1054 struct tcp_md5sig_key {
1055 u8 *key;
1056 u8 keylen;
1057 };
1058
1059 struct tcp4_md5sig_key {
1060 struct tcp_md5sig_key base;
1061 __be32 addr;
1062 };
1063
1064 struct tcp6_md5sig_key {
1065 struct tcp_md5sig_key base;
1066 #if 0
1067 u32 scope_id; /* XXX */
1068 #endif
1069 struct in6_addr addr;
1070 };
1071
1072 /* - sock block */
1073 struct tcp_md5sig_info {
1074 struct tcp4_md5sig_key *keys4;
1075 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1076 struct tcp6_md5sig_key *keys6;
1077 u32 entries6;
1078 u32 alloced6;
1079 #endif
1080 u32 entries4;
1081 u32 alloced4;
1082 };
1083
1084 /* - pseudo header */
1085 struct tcp4_pseudohdr {
1086 __be32 saddr;
1087 __be32 daddr;
1088 __u8 pad;
1089 __u8 protocol;
1090 __be16 len;
1091 };
1092
1093 struct tcp6_pseudohdr {
1094 struct in6_addr saddr;
1095 struct in6_addr daddr;
1096 __be32 len;
1097 __be32 protocol; /* including padding */
1098 };
1099
1100 union tcp_md5sum_block {
1101 struct tcp4_pseudohdr ip4;
1102 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1103 struct tcp6_pseudohdr ip6;
1104 #endif
1105 };
1106
1107 /* - pool: digest algorithm, hash description and scratch buffer */
1108 struct tcp_md5sig_pool {
1109 struct hash_desc md5_desc;
1110 union tcp_md5sum_block md5_blk;
1111 };
1112
1113 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1114
1115 /* - functions */
1116 extern int tcp_v4_calc_md5_hash(char *md5_hash,
1117 struct tcp_md5sig_key *key,
1118 struct sock *sk,
1119 struct dst_entry *dst,
1120 struct request_sock *req,
1121 struct tcphdr *th,
1122 int protocol,
1123 unsigned int tcplen);
1124 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1125 struct sock *addr_sk);
1126
1127 extern int tcp_v4_md5_do_add(struct sock *sk,
1128 __be32 addr,
1129 u8 *newkey,
1130 u8 newkeylen);
1131
1132 extern int tcp_v4_md5_do_del(struct sock *sk,
1133 __be32 addr);
1134
1135 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1136 extern void tcp_free_md5sig_pool(void);
1137
1138 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1139 extern void __tcp_put_md5sig_pool(void);
1140
1141 static inline
1142 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1143 {
1144 int cpu = get_cpu();
1145 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1146 if (!ret)
1147 put_cpu();
1148 return ret;
1149 }
1150
1151 static inline void tcp_put_md5sig_pool(void)
1152 {
1153 __tcp_put_md5sig_pool();
1154 put_cpu();
1155 }
1156
1157 /* write queue abstraction */
1158 static inline void tcp_write_queue_purge(struct sock *sk)
1159 {
1160 struct sk_buff *skb;
1161
1162 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1163 sk_wmem_free_skb(sk, skb);
1164 sk_mem_reclaim(sk);
1165 }
1166
1167 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1168 {
1169 struct sk_buff *skb = sk->sk_write_queue.next;
1170 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1171 return NULL;
1172 return skb;
1173 }
1174
1175 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1176 {
1177 struct sk_buff *skb = sk->sk_write_queue.prev;
1178 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1179 return NULL;
1180 return skb;
1181 }
1182
1183 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1184 {
1185 return skb->next;
1186 }
1187
1188 #define tcp_for_write_queue(skb, sk) \
1189 for (skb = (sk)->sk_write_queue.next; \
1190 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1191 skb = skb->next)
1192
1193 #define tcp_for_write_queue_from(skb, sk) \
1194 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\
1195 skb = skb->next)
1196
1197 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1198 for (tmp = skb->next; \
1199 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1200 skb = tmp, tmp = skb->next)
1201
1202 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1203 {
1204 return sk->sk_send_head;
1205 }
1206
1207 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
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 }
1213
1214 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1215 {
1216 if (sk->sk_send_head == skb_unlinked)
1217 sk->sk_send_head = NULL;
1218 }
1219
1220 static inline void tcp_init_send_head(struct sock *sk)
1221 {
1222 sk->sk_send_head = NULL;
1223 }
1224
1225 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1226 {
1227 __skb_queue_tail(&sk->sk_write_queue, skb);
1228 }
1229
1230 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1231 {
1232 __tcp_add_write_queue_tail(sk, skb);
1233
1234 /* Queue it, remembering where we must start sending. */
1235 if (sk->sk_send_head == NULL) {
1236 sk->sk_send_head = skb;
1237
1238 if (tcp_sk(sk)->highest_sack == NULL)
1239 tcp_sk(sk)->highest_sack = skb;
1240 }
1241 }
1242
1243 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1244 {
1245 __skb_queue_head(&sk->sk_write_queue, skb);
1246 }
1247
1248 /* Insert buff after skb on the write queue of sk. */
1249 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1250 struct sk_buff *buff,
1251 struct sock *sk)
1252 {
1253 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1254 }
1255
1256 /* Insert skb between prev and next on the write queue of sk. */
1257 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1258 struct sk_buff *skb,
1259 struct sock *sk)
1260 {
1261 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
1262
1263 if (sk->sk_send_head == skb)
1264 sk->sk_send_head = new;
1265 }
1266
1267 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1268 {
1269 __skb_unlink(skb, &sk->sk_write_queue);
1270 }
1271
1272 static inline int tcp_skb_is_last(const struct sock *sk,
1273 const struct sk_buff *skb)
1274 {
1275 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1276 }
1277
1278 static inline int tcp_write_queue_empty(struct sock *sk)
1279 {
1280 return skb_queue_empty(&sk->sk_write_queue);
1281 }
1282
1283 /* Start sequence of the highest skb with SACKed bit, valid only if
1284 * sacked > 0 or when the caller has ensured validity by itself.
1285 */
1286 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1287 {
1288 if (!tp->sacked_out)
1289 return tp->snd_una;
1290
1291 if (tp->highest_sack == NULL)
1292 return tp->snd_nxt;
1293
1294 return TCP_SKB_CB(tp->highest_sack)->seq;
1295 }
1296
1297 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1298 {
1299 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1300 tcp_write_queue_next(sk, skb);
1301 }
1302
1303 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1304 {
1305 return tcp_sk(sk)->highest_sack;
1306 }
1307
1308 static inline void tcp_highest_sack_reset(struct sock *sk)
1309 {
1310 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1311 }
1312
1313 /* Called when old skb is about to be deleted (to be combined with new skb) */
1314 static inline void tcp_highest_sack_combine(struct sock *sk,
1315 struct sk_buff *old,
1316 struct sk_buff *new)
1317 {
1318 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1319 tcp_sk(sk)->highest_sack = new;
1320 }
1321
1322 /* /proc */
1323 enum tcp_seq_states {
1324 TCP_SEQ_STATE_LISTENING,
1325 TCP_SEQ_STATE_OPENREQ,
1326 TCP_SEQ_STATE_ESTABLISHED,
1327 TCP_SEQ_STATE_TIME_WAIT,
1328 };
1329
1330 struct tcp_seq_afinfo {
1331 char *name;
1332 sa_family_t family;
1333 struct file_operations seq_fops;
1334 struct seq_operations seq_ops;
1335 };
1336
1337 struct tcp_iter_state {
1338 struct seq_net_private p;
1339 sa_family_t family;
1340 enum tcp_seq_states state;
1341 struct sock *syn_wait_sk;
1342 int bucket, sbucket, num, uid;
1343 };
1344
1345 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1346 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1347
1348 extern struct request_sock_ops tcp_request_sock_ops;
1349 extern struct request_sock_ops tcp6_request_sock_ops;
1350
1351 extern int tcp_v4_destroy_sock(struct sock *sk);
1352
1353 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1354 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1355
1356 #ifdef CONFIG_PROC_FS
1357 extern int tcp4_proc_init(void);
1358 extern void tcp4_proc_exit(void);
1359 #endif
1360
1361 /* TCP af-specific functions */
1362 struct tcp_sock_af_ops {
1363 #ifdef CONFIG_TCP_MD5SIG
1364 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1365 struct sock *addr_sk);
1366 int (*calc_md5_hash) (char *location,
1367 struct tcp_md5sig_key *md5,
1368 struct sock *sk,
1369 struct dst_entry *dst,
1370 struct request_sock *req,
1371 struct tcphdr *th,
1372 int protocol,
1373 unsigned int len);
1374 int (*md5_add) (struct sock *sk,
1375 struct sock *addr_sk,
1376 u8 *newkey,
1377 u8 len);
1378 int (*md5_parse) (struct sock *sk,
1379 char __user *optval,
1380 int optlen);
1381 #endif
1382 };
1383
1384 struct tcp_request_sock_ops {
1385 #ifdef CONFIG_TCP_MD5SIG
1386 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1387 struct request_sock *req);
1388 #endif
1389 };
1390
1391 extern void tcp_v4_init(void);
1392 extern void tcp_init(void);
1393
1394 #endif /* _TCP_H */
Linux kernel - Deliverables
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