?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
tcp/dccp: Consolidate common code for RFC 3390 conversion
[linux-2.6/x86.git] / include / net / tcp.h
blob6bc4b8148ca02cece574e44ccad4caddc22d1106
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 #define MAX_TCP_OPTION_SPACE 40
54
55 /*
56 * Never offer a window over 32767 without using window scaling. Some
57 * poor stacks do signed 16bit maths!
58 */
59 #define MAX_TCP_WINDOW 32767U
60
61 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
62 #define TCP_MIN_MSS 88U
63
64 /* Minimal RCV_MSS. */
65 #define TCP_MIN_RCVMSS 536U
66
67 /* The least MTU to use for probing */
68 #define TCP_BASE_MSS 512
69
70 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
71 #define TCP_FASTRETRANS_THRESH 3
72
73 /* Maximal reordering. */
74 #define TCP_MAX_REORDERING 127
75
76 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
77 #define TCP_MAX_QUICKACKS 16U
78
79 /* urg_data states */
80 #define TCP_URG_VALID 0x0100
81 #define TCP_URG_NOTYET 0x0200
82 #define TCP_URG_READ 0x0400
83
84 #define TCP_RETR1 3 /*
85 * This is how many retries it does before it
86 * tries to figure out if the gateway is
87 * down. Minimal RFC value is 3; it corresponds
88 * to ~3sec-8min depending on RTO.
89 */
90
91 #define TCP_RETR2 15 /*
92 * This should take at least
93 * 90 minutes to time out.
94 * RFC1122 says that the limit is 100 sec.
95 * 15 is ~13-30min depending on RTO.
96 */
97
98 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
99 * connection: ~180sec is RFC minimum */
100
101 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
102 * connection: ~180sec is RFC minimum */
103
104
105 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
106 * socket. 7 is ~50sec-16min.
107 */
108
109
110 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
111 * state, about 60 seconds */
112 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
113 /* BSD style FIN_WAIT2 deadlock breaker.
114 * It used to be 3min, new value is 60sec,
115 * to combine FIN-WAIT-2 timeout with
116 * TIME-WAIT timer.
117 */
118
119 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
120 #if HZ >= 100
121 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
122 #define TCP_ATO_MIN ((unsigned)(HZ/25))
123 #else
124 #define TCP_DELACK_MIN 4U
125 #define TCP_ATO_MIN 4U
126 #endif
127 #define TCP_RTO_MAX ((unsigned)(120*HZ))
128 #define TCP_RTO_MIN ((unsigned)(HZ/5))
129 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
130
131 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
132 * for local resources.
133 */
134
135 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
136 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
137 #define TCP_KEEPALIVE_INTVL (75*HZ)
138
139 #define MAX_TCP_KEEPIDLE 32767
140 #define MAX_TCP_KEEPINTVL 32767
141 #define MAX_TCP_KEEPCNT 127
142 #define MAX_TCP_SYNCNT 127
143
144 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
145
146 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
147 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
148 * after this time. It should be equal
149 * (or greater than) TCP_TIMEWAIT_LEN
150 * to provide reliability equal to one
151 * provided by timewait state.
152 */
153 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
154 * timestamps. It must be less than
155 * minimal timewait lifetime.
156 */
157 /*
158 * TCP option
159 */
160
161 #define TCPOPT_NOP 1 /* Padding */
162 #define TCPOPT_EOL 0 /* End of options */
163 #define TCPOPT_MSS 2 /* Segment size negotiating */
164 #define TCPOPT_WINDOW 3 /* Window scaling */
165 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
166 #define TCPOPT_SACK 5 /* SACK Block */
167 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
168 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
169
170 /*
171 * TCP option lengths
172 */
173
174 #define TCPOLEN_MSS 4
175 #define TCPOLEN_WINDOW 3
176 #define TCPOLEN_SACK_PERM 2
177 #define TCPOLEN_TIMESTAMP 10
178 #define TCPOLEN_MD5SIG 18
179
180 /* But this is what stacks really send out. */
181 #define TCPOLEN_TSTAMP_ALIGNED 12
182 #define TCPOLEN_WSCALE_ALIGNED 4
183 #define TCPOLEN_SACKPERM_ALIGNED 4
184 #define TCPOLEN_SACK_BASE 2
185 #define TCPOLEN_SACK_BASE_ALIGNED 4
186 #define TCPOLEN_SACK_PERBLOCK 8
187 #define TCPOLEN_MD5SIG_ALIGNED 20
188 #define TCPOLEN_MSS_ALIGNED 4
189
190 /* Flags in tp->nonagle */
191 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
192 #define TCP_NAGLE_CORK 2 /* Socket is corked */
193 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
194
195 extern struct inet_timewait_death_row tcp_death_row;
196
197 /* sysctl variables for tcp */
198 extern int sysctl_tcp_timestamps;
199 extern int sysctl_tcp_window_scaling;
200 extern int sysctl_tcp_sack;
201 extern int sysctl_tcp_fin_timeout;
202 extern int sysctl_tcp_keepalive_time;
203 extern int sysctl_tcp_keepalive_probes;
204 extern int sysctl_tcp_keepalive_intvl;
205 extern int sysctl_tcp_syn_retries;
206 extern int sysctl_tcp_synack_retries;
207 extern int sysctl_tcp_retries1;
208 extern int sysctl_tcp_retries2;
209 extern int sysctl_tcp_orphan_retries;
210 extern int sysctl_tcp_syncookies;
211 extern int sysctl_tcp_retrans_collapse;
212 extern int sysctl_tcp_stdurg;
213 extern int sysctl_tcp_rfc1337;
214 extern int sysctl_tcp_abort_on_overflow;
215 extern int sysctl_tcp_max_orphans;
216 extern int sysctl_tcp_fack;
217 extern int sysctl_tcp_reordering;
218 extern int sysctl_tcp_ecn;
219 extern int sysctl_tcp_dsack;
220 extern int sysctl_tcp_mem[3];
221 extern int sysctl_tcp_wmem[3];
222 extern int sysctl_tcp_rmem[3];
223 extern int sysctl_tcp_app_win;
224 extern int sysctl_tcp_adv_win_scale;
225 extern int sysctl_tcp_tw_reuse;
226 extern int sysctl_tcp_frto;
227 extern int sysctl_tcp_frto_response;
228 extern int sysctl_tcp_low_latency;
229 extern int sysctl_tcp_dma_copybreak;
230 extern int sysctl_tcp_nometrics_save;
231 extern int sysctl_tcp_moderate_rcvbuf;
232 extern int sysctl_tcp_tso_win_divisor;
233 extern int sysctl_tcp_abc;
234 extern int sysctl_tcp_mtu_probing;
235 extern int sysctl_tcp_base_mss;
236 extern int sysctl_tcp_workaround_signed_windows;
237 extern int sysctl_tcp_slow_start_after_idle;
238 extern int sysctl_tcp_max_ssthresh;
239
240 extern atomic_t tcp_memory_allocated;
241 extern atomic_t tcp_sockets_allocated;
242 extern int tcp_memory_pressure;
243
244 /*
245 * The next routines deal with comparing 32 bit unsigned ints
246 * and worry about wraparound (automatic with unsigned arithmetic).
247 */
248
249 static inline int before(__u32 seq1, __u32 seq2)
250 {
251 return (__s32)(seq1-seq2) < 0;
252 }
253 #define after(seq2, seq1) before(seq1, seq2)
254
255 /* is s2<=s1<=s3 ? */
256 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
257 {
258 return seq3 - seq2 >= seq1 - seq2;
259 }
260
261 static inline int tcp_too_many_orphans(struct sock *sk, int num)
262 {
263 return (num > sysctl_tcp_max_orphans) ||
264 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
265 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
266 }
267
268 extern struct proto tcp_prot;
269
270 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
271 #define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field)
272 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
273 #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
274
275 extern void tcp_v4_err(struct sk_buff *skb, u32);
276
277 extern void tcp_shutdown (struct sock *sk, int how);
278
279 extern int tcp_v4_rcv(struct sk_buff *skb);
280
281 extern int tcp_v4_remember_stamp(struct sock *sk);
282
283 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
284
285 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
286 struct msghdr *msg, size_t size);
287 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
288
289 extern int tcp_ioctl(struct sock *sk,
290 int cmd,
291 unsigned long arg);
292
293 extern int tcp_rcv_state_process(struct sock *sk,
294 struct sk_buff *skb,
295 struct tcphdr *th,
296 unsigned len);
297
298 extern int tcp_rcv_established(struct sock *sk,
299 struct sk_buff *skb,
300 struct tcphdr *th,
301 unsigned len);
302
303 extern void tcp_rcv_space_adjust(struct sock *sk);
304
305 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
306
307 extern int tcp_twsk_unique(struct sock *sk,
308 struct sock *sktw, void *twp);
309
310 extern void tcp_twsk_destructor(struct sock *sk);
311
312 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
313 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
314
315 static inline void tcp_dec_quickack_mode(struct sock *sk,
316 const unsigned int pkts)
317 {
318 struct inet_connection_sock *icsk = inet_csk(sk);
319
320 if (icsk->icsk_ack.quick) {
321 if (pkts >= icsk->icsk_ack.quick) {
322 icsk->icsk_ack.quick = 0;
323 /* Leaving quickack mode we deflate ATO. */
324 icsk->icsk_ack.ato = TCP_ATO_MIN;
325 } else
326 icsk->icsk_ack.quick -= pkts;
327 }
328 }
329
330 extern void tcp_enter_quickack_mode(struct sock *sk);
331
332 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
333 {
334 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
335 }
336
337 #define TCP_ECN_OK 1
338 #define TCP_ECN_QUEUE_CWR 2
339 #define TCP_ECN_DEMAND_CWR 4
340
341 static __inline__ void
342 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
343 {
344 if (sysctl_tcp_ecn && th->ece && th->cwr)
345 inet_rsk(req)->ecn_ok = 1;
346 }
347
348 enum tcp_tw_status
349 {
350 TCP_TW_SUCCESS = 0,
351 TCP_TW_RST = 1,
352 TCP_TW_ACK = 2,
353 TCP_TW_SYN = 3
354 };
355
356
357 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
358 struct sk_buff *skb,
359 const struct tcphdr *th);
360
361 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
362 struct request_sock *req,
363 struct request_sock **prev);
364 extern int tcp_child_process(struct sock *parent,
365 struct sock *child,
366 struct sk_buff *skb);
367 extern int tcp_use_frto(struct sock *sk);
368 extern void tcp_enter_frto(struct sock *sk);
369 extern void tcp_enter_loss(struct sock *sk, int how);
370 extern void tcp_clear_retrans(struct tcp_sock *tp);
371 extern void tcp_update_metrics(struct sock *sk);
372
373 extern void tcp_close(struct sock *sk,
374 long timeout);
375 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
376
377 extern int tcp_getsockopt(struct sock *sk, int level,
378 int optname,
379 char __user *optval,
380 int __user *optlen);
381 extern int tcp_setsockopt(struct sock *sk, int level,
382 int optname, char __user *optval,
383 int optlen);
384 extern int compat_tcp_getsockopt(struct sock *sk,
385 int level, int optname,
386 char __user *optval, int __user *optlen);
387 extern int compat_tcp_setsockopt(struct sock *sk,
388 int level, int optname,
389 char __user *optval, int optlen);
390 extern void tcp_set_keepalive(struct sock *sk, int val);
391 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
392 struct msghdr *msg,
393 size_t len, int nonblock,
394 int flags, int *addr_len);
395
396 extern void tcp_parse_options(struct sk_buff *skb,
397 struct tcp_options_received *opt_rx,
398 int estab);
399
400 extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
401
402 /*
403 * TCP v4 functions exported for the inet6 API
404 */
405
406 extern void tcp_v4_send_check(struct sock *sk, int len,
407 struct sk_buff *skb);
408
409 extern int tcp_v4_conn_request(struct sock *sk,
410 struct sk_buff *skb);
411
412 extern struct sock * tcp_create_openreq_child(struct sock *sk,
413 struct request_sock *req,
414 struct sk_buff *skb);
415
416 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
417 struct sk_buff *skb,
418 struct request_sock *req,
419 struct dst_entry *dst);
420
421 extern int tcp_v4_do_rcv(struct sock *sk,
422 struct sk_buff *skb);
423
424 extern int tcp_v4_connect(struct sock *sk,
425 struct sockaddr *uaddr,
426 int addr_len);
427
428 extern int tcp_connect(struct sock *sk);
429
430 extern struct sk_buff * tcp_make_synack(struct sock *sk,
431 struct dst_entry *dst,
432 struct request_sock *req);
433
434 extern int tcp_disconnect(struct sock *sk, int flags);
435
436
437 /* From syncookies.c */
438 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
439 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
440 struct ip_options *opt);
441 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
442 __u16 *mss);
443
444 extern __u32 cookie_init_timestamp(struct request_sock *req);
445 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
446
447 /* From net/ipv6/syncookies.c */
448 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
449 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
450 __u16 *mss);
451
452 /* tcp_output.c */
453
454 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
455 int nonagle);
456 extern int tcp_may_send_now(struct sock *sk);
457 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
458 extern void tcp_xmit_retransmit_queue(struct sock *);
459 extern void tcp_simple_retransmit(struct sock *);
460 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
461 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
462
463 extern void tcp_send_probe0(struct sock *);
464 extern void tcp_send_partial(struct sock *);
465 extern int tcp_write_wakeup(struct sock *);
466 extern void tcp_send_fin(struct sock *sk);
467 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
468 extern int tcp_send_synack(struct sock *);
469 extern void tcp_push_one(struct sock *, unsigned int mss_now);
470 extern void tcp_send_ack(struct sock *sk);
471 extern void tcp_send_delayed_ack(struct sock *sk);
472
473 /* tcp_input.c */
474 extern void tcp_cwnd_application_limited(struct sock *sk);
475
476 /* tcp_timer.c */
477 extern void tcp_init_xmit_timers(struct sock *);
478 static inline void tcp_clear_xmit_timers(struct sock *sk)
479 {
480 inet_csk_clear_xmit_timers(sk);
481 }
482
483 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
484 extern unsigned int tcp_current_mss(struct sock *sk, int large);
485
486 /* tcp.c */
487 extern void tcp_get_info(struct sock *, struct tcp_info *);
488
489 /* Read 'sendfile()'-style from a TCP socket */
490 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
491 unsigned int, size_t);
492 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
493 sk_read_actor_t recv_actor);
494
495 extern void tcp_initialize_rcv_mss(struct sock *sk);
496
497 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
498 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
499 extern void tcp_mtup_init(struct sock *sk);
500
501 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
502 {
503 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
504 ntohl(TCP_FLAG_ACK) |
505 snd_wnd);
506 }
507
508 static inline void tcp_fast_path_on(struct tcp_sock *tp)
509 {
510 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
511 }
512
513 static inline void tcp_fast_path_check(struct sock *sk)
514 {
515 struct tcp_sock *tp = tcp_sk(sk);
516
517 if (skb_queue_empty(&tp->out_of_order_queue) &&
518 tp->rcv_wnd &&
519 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
520 !tp->urg_data)
521 tcp_fast_path_on(tp);
522 }
523
524 /* Compute the actual receive window we are currently advertising.
525 * Rcv_nxt can be after the window if our peer push more data
526 * than the offered window.
527 */
528 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
529 {
530 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
531
532 if (win < 0)
533 win = 0;
534 return (u32) win;
535 }
536
537 /* Choose a new window, without checks for shrinking, and without
538 * scaling applied to the result. The caller does these things
539 * if necessary. This is a "raw" window selection.
540 */
541 extern u32 __tcp_select_window(struct sock *sk);
542
543 /* TCP timestamps are only 32-bits, this causes a slight
544 * complication on 64-bit systems since we store a snapshot
545 * of jiffies in the buffer control blocks below. We decided
546 * to use only the low 32-bits of jiffies and hide the ugly
547 * casts with the following macro.
548 */
549 #define tcp_time_stamp ((__u32)(jiffies))
550
551 /* This is what the send packet queuing engine uses to pass
552 * TCP per-packet control information to the transmission
553 * code. We also store the host-order sequence numbers in
554 * here too. This is 36 bytes on 32-bit architectures,
555 * 40 bytes on 64-bit machines, if this grows please adjust
556 * skbuff.h:skbuff->cb[xxx] size appropriately.
557 */
558 struct tcp_skb_cb {
559 union {
560 struct inet_skb_parm h4;
561 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
562 struct inet6_skb_parm h6;
563 #endif
564 } header; /* For incoming frames */
565 __u32 seq; /* Starting sequence number */
566 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
567 __u32 when; /* used to compute rtt's */
568 __u8 flags; /* TCP header flags. */
569
570 /* NOTE: These must match up to the flags byte in a
571 * real TCP header.
572 */
573 #define TCPCB_FLAG_FIN 0x01
574 #define TCPCB_FLAG_SYN 0x02
575 #define TCPCB_FLAG_RST 0x04
576 #define TCPCB_FLAG_PSH 0x08
577 #define TCPCB_FLAG_ACK 0x10
578 #define TCPCB_FLAG_URG 0x20
579 #define TCPCB_FLAG_ECE 0x40
580 #define TCPCB_FLAG_CWR 0x80
581
582 __u8 sacked; /* State flags for SACK/FACK. */
583 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
584 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
585 #define TCPCB_LOST 0x04 /* SKB is lost */
586 #define TCPCB_TAGBITS 0x07 /* All tag bits */
587
588 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
589 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
590
591 __u16 urg_ptr; /* Valid w/URG flags is set. */
592 __u32 ack_seq; /* Sequence number ACK'd */
593 };
594
595 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
596
597 /* Due to TSO, an SKB can be composed of multiple actual
598 * packets. To keep these tracked properly, we use this.
599 */
600 static inline int tcp_skb_pcount(const struct sk_buff *skb)
601 {
602 return skb_shinfo(skb)->gso_segs;
603 }
604
605 /* This is valid iff tcp_skb_pcount() > 1. */
606 static inline int tcp_skb_mss(const struct sk_buff *skb)
607 {
608 return skb_shinfo(skb)->gso_size;
609 }
610
611 static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
612 {
613 if (*count) {
614 *count -= decr;
615 if ((int)*count < 0)
616 *count = 0;
617 }
618 }
619
620 static inline void tcp_dec_pcount_approx(__u32 *count,
621 const struct sk_buff *skb)
622 {
623 tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
624 }
625
626 /* Events passed to congestion control interface */
627 enum tcp_ca_event {
628 CA_EVENT_TX_START, /* first transmit when no packets in flight */
629 CA_EVENT_CWND_RESTART, /* congestion window restart */
630 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
631 CA_EVENT_FRTO, /* fast recovery timeout */
632 CA_EVENT_LOSS, /* loss timeout */
633 CA_EVENT_FAST_ACK, /* in sequence ack */
634 CA_EVENT_SLOW_ACK, /* other ack */
635 };
636
637 /*
638 * Interface for adding new TCP congestion control handlers
639 */
640 #define TCP_CA_NAME_MAX 16
641 #define TCP_CA_MAX 128
642 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
643
644 #define TCP_CONG_NON_RESTRICTED 0x1
645 #define TCP_CONG_RTT_STAMP 0x2
646
647 struct tcp_congestion_ops {
648 struct list_head list;
649 unsigned long flags;
650
651 /* initialize private data (optional) */
652 void (*init)(struct sock *sk);
653 /* cleanup private data (optional) */
654 void (*release)(struct sock *sk);
655
656 /* return slow start threshold (required) */
657 u32 (*ssthresh)(struct sock *sk);
658 /* lower bound for congestion window (optional) */
659 u32 (*min_cwnd)(const struct sock *sk);
660 /* do new cwnd calculation (required) */
661 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
662 /* call before changing ca_state (optional) */
663 void (*set_state)(struct sock *sk, u8 new_state);
664 /* call when cwnd event occurs (optional) */
665 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
666 /* new value of cwnd after loss (optional) */
667 u32 (*undo_cwnd)(struct sock *sk);
668 /* hook for packet ack accounting (optional) */
669 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
670 /* get info for inet_diag (optional) */
671 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
672
673 char name[TCP_CA_NAME_MAX];
674 struct module *owner;
675 };
676
677 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
678 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
679
680 extern void tcp_init_congestion_control(struct sock *sk);
681 extern void tcp_cleanup_congestion_control(struct sock *sk);
682 extern int tcp_set_default_congestion_control(const char *name);
683 extern void tcp_get_default_congestion_control(char *name);
684 extern void tcp_get_available_congestion_control(char *buf, size_t len);
685 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
686 extern int tcp_set_allowed_congestion_control(char *allowed);
687 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
688 extern void tcp_slow_start(struct tcp_sock *tp);
689
690 extern struct tcp_congestion_ops tcp_init_congestion_ops;
691 extern u32 tcp_reno_ssthresh(struct sock *sk);
692 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
693 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
694 extern struct tcp_congestion_ops tcp_reno;
695
696 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
697 {
698 struct inet_connection_sock *icsk = inet_csk(sk);
699
700 if (icsk->icsk_ca_ops->set_state)
701 icsk->icsk_ca_ops->set_state(sk, ca_state);
702 icsk->icsk_ca_state = ca_state;
703 }
704
705 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
706 {
707 const struct inet_connection_sock *icsk = inet_csk(sk);
708
709 if (icsk->icsk_ca_ops->cwnd_event)
710 icsk->icsk_ca_ops->cwnd_event(sk, event);
711 }
712
713 /* These functions determine how the current flow behaves in respect of SACK
714 * handling. SACK is negotiated with the peer, and therefore it can vary
715 * between different flows.
716 *
717 * tcp_is_sack - SACK enabled
718 * tcp_is_reno - No SACK
719 * tcp_is_fack - FACK enabled, implies SACK enabled
720 */
721 static inline int tcp_is_sack(const struct tcp_sock *tp)
722 {
723 return tp->rx_opt.sack_ok;
724 }
725
726 static inline int tcp_is_reno(const struct tcp_sock *tp)
727 {
728 return !tcp_is_sack(tp);
729 }
730
731 static inline int tcp_is_fack(const struct tcp_sock *tp)
732 {
733 return tp->rx_opt.sack_ok & 2;
734 }
735
736 static inline void tcp_enable_fack(struct tcp_sock *tp)
737 {
738 tp->rx_opt.sack_ok |= 2;
739 }
740
741 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
742 {
743 return tp->sacked_out + tp->lost_out;
744 }
745
746 /* This determines how many packets are "in the network" to the best
747 * of our knowledge. In many cases it is conservative, but where
748 * detailed information is available from the receiver (via SACK
749 * blocks etc.) we can make more aggressive calculations.
750 *
751 * Use this for decisions involving congestion control, use just
752 * tp->packets_out to determine if the send queue is empty or not.
753 *
754 * Read this equation as:
755 *
756 * "Packets sent once on transmission queue" MINUS
757 * "Packets left network, but not honestly ACKed yet" PLUS
758 * "Packets fast retransmitted"
759 */
760 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
761 {
762 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
763 }
764
765 extern int tcp_limit_reno_sacked(struct tcp_sock *tp);
766
767 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
768 * The exception is rate halving phase, when cwnd is decreasing towards
769 * ssthresh.
770 */
771 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
772 {
773 const struct tcp_sock *tp = tcp_sk(sk);
774 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
775 return tp->snd_ssthresh;
776 else
777 return max(tp->snd_ssthresh,
778 ((tp->snd_cwnd >> 1) +
779 (tp->snd_cwnd >> 2)));
780 }
781
782 /* Use define here intentionally to get WARN_ON location shown at the caller */
783 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
784
785 /*
786 * Convert RFC3390 larger initial windows into an equivalent number of packets.
787 *
788 * John Heffner states:
789 *
790 * The RFC specifies a window of no more than 4380 bytes
791 * unless 2*MSS > 4380. Reading the pseudocode in the RFC
792 * is a bit misleading because they use a clamp at 4380 bytes
793 * rather than a multiplier in the relevant range.
794 */
795 static inline u32 rfc3390_bytes_to_packets(const u32 bytes)
796 {
797 return bytes <= 1095 ? 4 : (bytes > 1460 ? 2 : 3);
798 }
799
800 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
801 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
802
803 /* Slow start with delack produces 3 packets of burst, so that
804 * it is safe "de facto". This will be the default - same as
805 * the default reordering threshold - but if reordering increases,
806 * we must be able to allow cwnd to burst at least this much in order
807 * to not pull it back when holes are filled.
808 */
809 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
810 {
811 return tp->reordering;
812 }
813
814 /* Returns end sequence number of the receiver's advertised window */
815 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
816 {
817 return tp->snd_una + tp->snd_wnd;
818 }
819 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
820
821 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
822 const struct sk_buff *skb)
823 {
824 if (skb->len < mss)
825 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
826 }
827
828 static inline void tcp_check_probe_timer(struct sock *sk)
829 {
830 struct tcp_sock *tp = tcp_sk(sk);
831 const struct inet_connection_sock *icsk = inet_csk(sk);
832
833 if (!tp->packets_out && !icsk->icsk_pending)
834 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
835 icsk->icsk_rto, TCP_RTO_MAX);
836 }
837
838 static inline void tcp_push_pending_frames(struct sock *sk)
839 {
840 struct tcp_sock *tp = tcp_sk(sk);
841
842 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
843 }
844
845 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
846 {
847 tp->snd_wl1 = seq;
848 }
849
850 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
851 {
852 tp->snd_wl1 = seq;
853 }
854
855 /*
856 * Calculate(/check) TCP checksum
857 */
858 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
859 __be32 daddr, __wsum base)
860 {
861 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
862 }
863
864 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
865 {
866 return __skb_checksum_complete(skb);
867 }
868
869 static inline int tcp_checksum_complete(struct sk_buff *skb)
870 {
871 return !skb_csum_unnecessary(skb) &&
872 __tcp_checksum_complete(skb);
873 }
874
875 /* Prequeue for VJ style copy to user, combined with checksumming. */
876
877 static inline void tcp_prequeue_init(struct tcp_sock *tp)
878 {
879 tp->ucopy.task = NULL;
880 tp->ucopy.len = 0;
881 tp->ucopy.memory = 0;
882 skb_queue_head_init(&tp->ucopy.prequeue);
883 #ifdef CONFIG_NET_DMA
884 tp->ucopy.dma_chan = NULL;
885 tp->ucopy.wakeup = 0;
886 tp->ucopy.pinned_list = NULL;
887 tp->ucopy.dma_cookie = 0;
888 #endif
889 }
890
891 /* Packet is added to VJ-style prequeue for processing in process
892 * context, if a reader task is waiting. Apparently, this exciting
893 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
894 * failed somewhere. Latency? Burstiness? Well, at least now we will
895 * see, why it failed. 8)8) --ANK
896 *
897 * NOTE: is this not too big to inline?
898 */
899 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
900 {
901 struct tcp_sock *tp = tcp_sk(sk);
902
903 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
904 __skb_queue_tail(&tp->ucopy.prequeue, skb);
905 tp->ucopy.memory += skb->truesize;
906 if (tp->ucopy.memory > sk->sk_rcvbuf) {
907 struct sk_buff *skb1;
908
909 BUG_ON(sock_owned_by_user(sk));
910
911 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
912 sk->sk_backlog_rcv(sk, skb1);
913 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPREQUEUEDROPPED);
914 }
915
916 tp->ucopy.memory = 0;
917 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
918 wake_up_interruptible(sk->sk_sleep);
919 if (!inet_csk_ack_scheduled(sk))
920 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
921 (3 * TCP_RTO_MIN) / 4,
922 TCP_RTO_MAX);
923 }
924 return 1;
925 }
926 return 0;
927 }
928
929
930 #undef STATE_TRACE
931
932 #ifdef STATE_TRACE
933 static const char *statename[]={
934 "Unused","Established","Syn Sent","Syn Recv",
935 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
936 "Close Wait","Last ACK","Listen","Closing"
937 };
938 #endif
939 extern void tcp_set_state(struct sock *sk, int state);
940
941 extern void tcp_done(struct sock *sk);
942
943 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
944 {
945 rx_opt->dsack = 0;
946 rx_opt->eff_sacks = 0;
947 rx_opt->num_sacks = 0;
948 }
949
950 /* Determine a window scaling and initial window to offer. */
951 extern void tcp_select_initial_window(int __space, __u32 mss,
952 __u32 *rcv_wnd, __u32 *window_clamp,
953 int wscale_ok, __u8 *rcv_wscale);
954
955 static inline int tcp_win_from_space(int space)
956 {
957 return sysctl_tcp_adv_win_scale<=0 ?
958 (space>>(-sysctl_tcp_adv_win_scale)) :
959 space - (space>>sysctl_tcp_adv_win_scale);
960 }
961
962 /* Note: caller must be prepared to deal with negative returns */
963 static inline int tcp_space(const struct sock *sk)
964 {
965 return tcp_win_from_space(sk->sk_rcvbuf -
966 atomic_read(&sk->sk_rmem_alloc));
967 }
968
969 static inline int tcp_full_space(const struct sock *sk)
970 {
971 return tcp_win_from_space(sk->sk_rcvbuf);
972 }
973
974 static inline void tcp_openreq_init(struct request_sock *req,
975 struct tcp_options_received *rx_opt,
976 struct sk_buff *skb)
977 {
978 struct inet_request_sock *ireq = inet_rsk(req);
979
980 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
981 req->cookie_ts = 0;
982 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
983 req->mss = rx_opt->mss_clamp;
984 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
985 ireq->tstamp_ok = rx_opt->tstamp_ok;
986 ireq->sack_ok = rx_opt->sack_ok;
987 ireq->snd_wscale = rx_opt->snd_wscale;
988 ireq->wscale_ok = rx_opt->wscale_ok;
989 ireq->acked = 0;
990 ireq->ecn_ok = 0;
991 ireq->rmt_port = tcp_hdr(skb)->source;
992 }
993
994 extern void tcp_enter_memory_pressure(struct sock *sk);
995
996 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
997 {
998 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
999 }
1000
1001 static inline int keepalive_time_when(const struct tcp_sock *tp)
1002 {
1003 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
1004 }
1005
1006 static inline int tcp_fin_time(const struct sock *sk)
1007 {
1008 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1009 const int rto = inet_csk(sk)->icsk_rto;
1010
1011 if (fin_timeout < (rto << 2) - (rto >> 1))
1012 fin_timeout = (rto << 2) - (rto >> 1);
1013
1014 return fin_timeout;
1015 }
1016
1017 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1018 {
1019 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1020 return 0;
1021 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1022 return 0;
1023
1024 /* RST segments are not recommended to carry timestamp,
1025 and, if they do, it is recommended to ignore PAWS because
1026 "their cleanup function should take precedence over timestamps."
1027 Certainly, it is mistake. It is necessary to understand the reasons
1028 of this constraint to relax it: if peer reboots, clock may go
1029 out-of-sync and half-open connections will not be reset.
1030 Actually, the problem would be not existing if all
1031 the implementations followed draft about maintaining clock
1032 via reboots. Linux-2.2 DOES NOT!
1033
1034 However, we can relax time bounds for RST segments to MSL.
1035 */
1036 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1037 return 0;
1038 return 1;
1039 }
1040
1041 #define TCP_CHECK_TIMER(sk) do { } while (0)
1042
1043 static inline void tcp_mib_init(struct net *net)
1044 {
1045 /* See RFC 2012 */
1046 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
1047 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1048 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1049 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
1050 }
1051
1052 /* from STCP */
1053 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1054 {
1055 tp->lost_skb_hint = NULL;
1056 tp->scoreboard_skb_hint = NULL;
1057 tp->retransmit_skb_hint = NULL;
1058 tp->forward_skb_hint = NULL;
1059 }
1060
1061 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1062 {
1063 tcp_clear_retrans_hints_partial(tp);
1064 }
1065
1066 /* MD5 Signature */
1067 struct crypto_hash;
1068
1069 /* - key database */
1070 struct tcp_md5sig_key {
1071 u8 *key;
1072 u8 keylen;
1073 };
1074
1075 struct tcp4_md5sig_key {
1076 struct tcp_md5sig_key base;
1077 __be32 addr;
1078 };
1079
1080 struct tcp6_md5sig_key {
1081 struct tcp_md5sig_key base;
1082 #if 0
1083 u32 scope_id; /* XXX */
1084 #endif
1085 struct in6_addr addr;
1086 };
1087
1088 /* - sock block */
1089 struct tcp_md5sig_info {
1090 struct tcp4_md5sig_key *keys4;
1091 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1092 struct tcp6_md5sig_key *keys6;
1093 u32 entries6;
1094 u32 alloced6;
1095 #endif
1096 u32 entries4;
1097 u32 alloced4;
1098 };
1099
1100 /* - pseudo header */
1101 struct tcp4_pseudohdr {
1102 __be32 saddr;
1103 __be32 daddr;
1104 __u8 pad;
1105 __u8 protocol;
1106 __be16 len;
1107 };
1108
1109 struct tcp6_pseudohdr {
1110 struct in6_addr saddr;
1111 struct in6_addr daddr;
1112 __be32 len;
1113 __be32 protocol; /* including padding */
1114 };
1115
1116 union tcp_md5sum_block {
1117 struct tcp4_pseudohdr ip4;
1118 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1119 struct tcp6_pseudohdr ip6;
1120 #endif
1121 };
1122
1123 /* - pool: digest algorithm, hash description and scratch buffer */
1124 struct tcp_md5sig_pool {
1125 struct hash_desc md5_desc;
1126 union tcp_md5sum_block md5_blk;
1127 };
1128
1129 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1130
1131 /* - functions */
1132 extern int tcp_v4_md5_hash_skb(char *md5_hash,
1133 struct tcp_md5sig_key *key,
1134 struct sock *sk,
1135 struct request_sock *req,
1136 struct sk_buff *skb);
1137
1138 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1139 struct sock *addr_sk);
1140
1141 extern int tcp_v4_md5_do_add(struct sock *sk,
1142 __be32 addr,
1143 u8 *newkey,
1144 u8 newkeylen);
1145
1146 extern int tcp_v4_md5_do_del(struct sock *sk,
1147 __be32 addr);
1148
1149 #ifdef CONFIG_TCP_MD5SIG
1150 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1151 &(struct tcp_md5sig_key) { \
1152 .key = (twsk)->tw_md5_key, \
1153 .keylen = (twsk)->tw_md5_keylen, \
1154 } : NULL)
1155 #else
1156 #define tcp_twsk_md5_key(twsk) NULL
1157 #endif
1158
1159 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1160 extern void tcp_free_md5sig_pool(void);
1161
1162 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1163 extern void __tcp_put_md5sig_pool(void);
1164 extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *);
1165 extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *,
1166 unsigned header_len);
1167 extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1168 struct tcp_md5sig_key *key);
1169
1170 static inline
1171 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1172 {
1173 int cpu = get_cpu();
1174 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1175 if (!ret)
1176 put_cpu();
1177 return ret;
1178 }
1179
1180 static inline void tcp_put_md5sig_pool(void)
1181 {
1182 __tcp_put_md5sig_pool();
1183 put_cpu();
1184 }
1185
1186 /* write queue abstraction */
1187 static inline void tcp_write_queue_purge(struct sock *sk)
1188 {
1189 struct sk_buff *skb;
1190
1191 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1192 sk_wmem_free_skb(sk, skb);
1193 sk_mem_reclaim(sk);
1194 }
1195
1196 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1197 {
1198 struct sk_buff *skb = sk->sk_write_queue.next;
1199 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1200 return NULL;
1201 return skb;
1202 }
1203
1204 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1205 {
1206 struct sk_buff *skb = sk->sk_write_queue.prev;
1207 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1208 return NULL;
1209 return skb;
1210 }
1211
1212 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1213 {
1214 return skb->next;
1215 }
1216
1217 #define tcp_for_write_queue(skb, sk) \
1218 for (skb = (sk)->sk_write_queue.next; \
1219 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1220 skb = skb->next)
1221
1222 #define tcp_for_write_queue_from(skb, sk) \
1223 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\
1224 skb = skb->next)
1225
1226 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1227 for (tmp = skb->next; \
1228 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1229 skb = tmp, tmp = skb->next)
1230
1231 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1232 {
1233 return sk->sk_send_head;
1234 }
1235
1236 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1237 {
1238 sk->sk_send_head = skb->next;
1239 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
1240 sk->sk_send_head = NULL;
1241 }
1242
1243 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1244 {
1245 if (sk->sk_send_head == skb_unlinked)
1246 sk->sk_send_head = NULL;
1247 }
1248
1249 static inline void tcp_init_send_head(struct sock *sk)
1250 {
1251 sk->sk_send_head = NULL;
1252 }
1253
1254 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1255 {
1256 __skb_queue_tail(&sk->sk_write_queue, skb);
1257 }
1258
1259 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1260 {
1261 __tcp_add_write_queue_tail(sk, skb);
1262
1263 /* Queue it, remembering where we must start sending. */
1264 if (sk->sk_send_head == NULL) {
1265 sk->sk_send_head = skb;
1266
1267 if (tcp_sk(sk)->highest_sack == NULL)
1268 tcp_sk(sk)->highest_sack = skb;
1269 }
1270 }
1271
1272 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1273 {
1274 __skb_queue_head(&sk->sk_write_queue, skb);
1275 }
1276
1277 /* Insert buff after skb on the write queue of sk. */
1278 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1279 struct sk_buff *buff,
1280 struct sock *sk)
1281 {
1282 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1283 }
1284
1285 /* Insert skb between prev and next on the write queue of sk. */
1286 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1287 struct sk_buff *skb,
1288 struct sock *sk)
1289 {
1290 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
1291
1292 if (sk->sk_send_head == skb)
1293 sk->sk_send_head = new;
1294 }
1295
1296 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1297 {
1298 __skb_unlink(skb, &sk->sk_write_queue);
1299 }
1300
1301 static inline int tcp_skb_is_last(const struct sock *sk,
1302 const struct sk_buff *skb)
1303 {
1304 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1305 }
1306
1307 static inline int tcp_write_queue_empty(struct sock *sk)
1308 {
1309 return skb_queue_empty(&sk->sk_write_queue);
1310 }
1311
1312 /* Start sequence of the highest skb with SACKed bit, valid only if
1313 * sacked > 0 or when the caller has ensured validity by itself.
1314 */
1315 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1316 {
1317 if (!tp->sacked_out)
1318 return tp->snd_una;
1319
1320 if (tp->highest_sack == NULL)
1321 return tp->snd_nxt;
1322
1323 return TCP_SKB_CB(tp->highest_sack)->seq;
1324 }
1325
1326 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1327 {
1328 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1329 tcp_write_queue_next(sk, skb);
1330 }
1331
1332 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1333 {
1334 return tcp_sk(sk)->highest_sack;
1335 }
1336
1337 static inline void tcp_highest_sack_reset(struct sock *sk)
1338 {
1339 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1340 }
1341
1342 /* Called when old skb is about to be deleted (to be combined with new skb) */
1343 static inline void tcp_highest_sack_combine(struct sock *sk,
1344 struct sk_buff *old,
1345 struct sk_buff *new)
1346 {
1347 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1348 tcp_sk(sk)->highest_sack = new;
1349 }
1350
1351 /* /proc */
1352 enum tcp_seq_states {
1353 TCP_SEQ_STATE_LISTENING,
1354 TCP_SEQ_STATE_OPENREQ,
1355 TCP_SEQ_STATE_ESTABLISHED,
1356 TCP_SEQ_STATE_TIME_WAIT,
1357 };
1358
1359 struct tcp_seq_afinfo {
1360 char *name;
1361 sa_family_t family;
1362 struct file_operations seq_fops;
1363 struct seq_operations seq_ops;
1364 };
1365
1366 struct tcp_iter_state {
1367 struct seq_net_private p;
1368 sa_family_t family;
1369 enum tcp_seq_states state;
1370 struct sock *syn_wait_sk;
1371 int bucket, sbucket, num, uid;
1372 };
1373
1374 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1375 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1376
1377 extern struct request_sock_ops tcp_request_sock_ops;
1378 extern struct request_sock_ops tcp6_request_sock_ops;
1379
1380 extern void tcp_v4_destroy_sock(struct sock *sk);
1381
1382 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1383 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1384
1385 #ifdef CONFIG_PROC_FS
1386 extern int tcp4_proc_init(void);
1387 extern void tcp4_proc_exit(void);
1388 #endif
1389
1390 /* TCP af-specific functions */
1391 struct tcp_sock_af_ops {
1392 #ifdef CONFIG_TCP_MD5SIG
1393 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1394 struct sock *addr_sk);
1395 int (*calc_md5_hash) (char *location,
1396 struct tcp_md5sig_key *md5,
1397 struct sock *sk,
1398 struct request_sock *req,
1399 struct sk_buff *skb);
1400 int (*md5_add) (struct sock *sk,
1401 struct sock *addr_sk,
1402 u8 *newkey,
1403 u8 len);
1404 int (*md5_parse) (struct sock *sk,
1405 char __user *optval,
1406 int optlen);
1407 #endif
1408 };
1409
1410 struct tcp_request_sock_ops {
1411 #ifdef CONFIG_TCP_MD5SIG
1412 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1413 struct request_sock *req);
1414 #endif
1415 };
1416
1417 extern void tcp_v4_init(void);
1418 extern void tcp_init(void);
1419
1420 #endif /* _TCP_H */
x86 "subsystem" repository