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V4L/DVB (11069): au8522: add mutex protecting use of hybrid state
[linux-2.6/btrfs-unstable.git] / include / net / tcp.h
blobe54c76d754951159c71a2bacdce45ec1a1dab593
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 struct percpu_counter 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 struct percpu_counter 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);
485
486 /* Bound MSS / TSO packet size with the half of the window */
487 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
488 {
489 if (tp->max_window && pktsize > (tp->max_window >> 1))
490 return max(tp->max_window >> 1, 68U - tp->tcp_header_len);
491 else
492 return pktsize;
493 }
494
495 /* tcp.c */
496 extern void tcp_get_info(struct sock *, struct tcp_info *);
497
498 /* Read 'sendfile()'-style from a TCP socket */
499 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
500 unsigned int, size_t);
501 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
502 sk_read_actor_t recv_actor);
503
504 extern void tcp_initialize_rcv_mss(struct sock *sk);
505
506 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
507 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
508 extern void tcp_mtup_init(struct sock *sk);
509
510 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
511 {
512 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
513 ntohl(TCP_FLAG_ACK) |
514 snd_wnd);
515 }
516
517 static inline void tcp_fast_path_on(struct tcp_sock *tp)
518 {
519 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
520 }
521
522 static inline void tcp_fast_path_check(struct sock *sk)
523 {
524 struct tcp_sock *tp = tcp_sk(sk);
525
526 if (skb_queue_empty(&tp->out_of_order_queue) &&
527 tp->rcv_wnd &&
528 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
529 !tp->urg_data)
530 tcp_fast_path_on(tp);
531 }
532
533 /* Compute the actual receive window we are currently advertising.
534 * Rcv_nxt can be after the window if our peer push more data
535 * than the offered window.
536 */
537 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
538 {
539 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
540
541 if (win < 0)
542 win = 0;
543 return (u32) win;
544 }
545
546 /* Choose a new window, without checks for shrinking, and without
547 * scaling applied to the result. The caller does these things
548 * if necessary. This is a "raw" window selection.
549 */
550 extern u32 __tcp_select_window(struct sock *sk);
551
552 /* TCP timestamps are only 32-bits, this causes a slight
553 * complication on 64-bit systems since we store a snapshot
554 * of jiffies in the buffer control blocks below. We decided
555 * to use only the low 32-bits of jiffies and hide the ugly
556 * casts with the following macro.
557 */
558 #define tcp_time_stamp ((__u32)(jiffies))
559
560 /* This is what the send packet queuing engine uses to pass
561 * TCP per-packet control information to the transmission
562 * code. We also store the host-order sequence numbers in
563 * here too. This is 36 bytes on 32-bit architectures,
564 * 40 bytes on 64-bit machines, if this grows please adjust
565 * skbuff.h:skbuff->cb[xxx] size appropriately.
566 */
567 struct tcp_skb_cb {
568 union {
569 struct inet_skb_parm h4;
570 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
571 struct inet6_skb_parm h6;
572 #endif
573 } header; /* For incoming frames */
574 __u32 seq; /* Starting sequence number */
575 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
576 __u32 when; /* used to compute rtt's */
577 __u8 flags; /* TCP header flags. */
578
579 /* NOTE: These must match up to the flags byte in a
580 * real TCP header.
581 */
582 #define TCPCB_FLAG_FIN 0x01
583 #define TCPCB_FLAG_SYN 0x02
584 #define TCPCB_FLAG_RST 0x04
585 #define TCPCB_FLAG_PSH 0x08
586 #define TCPCB_FLAG_ACK 0x10
587 #define TCPCB_FLAG_URG 0x20
588 #define TCPCB_FLAG_ECE 0x40
589 #define TCPCB_FLAG_CWR 0x80
590
591 __u8 sacked; /* State flags for SACK/FACK. */
592 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
593 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
594 #define TCPCB_LOST 0x04 /* SKB is lost */
595 #define TCPCB_TAGBITS 0x07 /* All tag bits */
596
597 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
598 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
599
600 __u32 ack_seq; /* Sequence number ACK'd */
601 };
602
603 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
604
605 /* Due to TSO, an SKB can be composed of multiple actual
606 * packets. To keep these tracked properly, we use this.
607 */
608 static inline int tcp_skb_pcount(const struct sk_buff *skb)
609 {
610 return skb_shinfo(skb)->gso_segs;
611 }
612
613 /* This is valid iff tcp_skb_pcount() > 1. */
614 static inline int tcp_skb_mss(const struct sk_buff *skb)
615 {
616 return skb_shinfo(skb)->gso_size;
617 }
618
619 static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
620 {
621 if (*count) {
622 *count -= decr;
623 if ((int)*count < 0)
624 *count = 0;
625 }
626 }
627
628 static inline void tcp_dec_pcount_approx(__u32 *count,
629 const struct sk_buff *skb)
630 {
631 tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
632 }
633
634 /* Events passed to congestion control interface */
635 enum tcp_ca_event {
636 CA_EVENT_TX_START, /* first transmit when no packets in flight */
637 CA_EVENT_CWND_RESTART, /* congestion window restart */
638 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
639 CA_EVENT_FRTO, /* fast recovery timeout */
640 CA_EVENT_LOSS, /* loss timeout */
641 CA_EVENT_FAST_ACK, /* in sequence ack */
642 CA_EVENT_SLOW_ACK, /* other ack */
643 };
644
645 /*
646 * Interface for adding new TCP congestion control handlers
647 */
648 #define TCP_CA_NAME_MAX 16
649 #define TCP_CA_MAX 128
650 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
651
652 #define TCP_CONG_NON_RESTRICTED 0x1
653 #define TCP_CONG_RTT_STAMP 0x2
654
655 struct tcp_congestion_ops {
656 struct list_head list;
657 unsigned long flags;
658
659 /* initialize private data (optional) */
660 void (*init)(struct sock *sk);
661 /* cleanup private data (optional) */
662 void (*release)(struct sock *sk);
663
664 /* return slow start threshold (required) */
665 u32 (*ssthresh)(struct sock *sk);
666 /* lower bound for congestion window (optional) */
667 u32 (*min_cwnd)(const struct sock *sk);
668 /* do new cwnd calculation (required) */
669 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
670 /* call before changing ca_state (optional) */
671 void (*set_state)(struct sock *sk, u8 new_state);
672 /* call when cwnd event occurs (optional) */
673 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
674 /* new value of cwnd after loss (optional) */
675 u32 (*undo_cwnd)(struct sock *sk);
676 /* hook for packet ack accounting (optional) */
677 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
678 /* get info for inet_diag (optional) */
679 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
680
681 char name[TCP_CA_NAME_MAX];
682 struct module *owner;
683 };
684
685 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
686 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
687
688 extern void tcp_init_congestion_control(struct sock *sk);
689 extern void tcp_cleanup_congestion_control(struct sock *sk);
690 extern int tcp_set_default_congestion_control(const char *name);
691 extern void tcp_get_default_congestion_control(char *name);
692 extern void tcp_get_available_congestion_control(char *buf, size_t len);
693 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
694 extern int tcp_set_allowed_congestion_control(char *allowed);
695 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
696 extern void tcp_slow_start(struct tcp_sock *tp);
697 extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w);
698
699 extern struct tcp_congestion_ops tcp_init_congestion_ops;
700 extern u32 tcp_reno_ssthresh(struct sock *sk);
701 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
702 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
703 extern struct tcp_congestion_ops tcp_reno;
704
705 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
706 {
707 struct inet_connection_sock *icsk = inet_csk(sk);
708
709 if (icsk->icsk_ca_ops->set_state)
710 icsk->icsk_ca_ops->set_state(sk, ca_state);
711 icsk->icsk_ca_state = ca_state;
712 }
713
714 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
715 {
716 const struct inet_connection_sock *icsk = inet_csk(sk);
717
718 if (icsk->icsk_ca_ops->cwnd_event)
719 icsk->icsk_ca_ops->cwnd_event(sk, event);
720 }
721
722 /* These functions determine how the current flow behaves in respect of SACK
723 * handling. SACK is negotiated with the peer, and therefore it can vary
724 * between different flows.
725 *
726 * tcp_is_sack - SACK enabled
727 * tcp_is_reno - No SACK
728 * tcp_is_fack - FACK enabled, implies SACK enabled
729 */
730 static inline int tcp_is_sack(const struct tcp_sock *tp)
731 {
732 return tp->rx_opt.sack_ok;
733 }
734
735 static inline int tcp_is_reno(const struct tcp_sock *tp)
736 {
737 return !tcp_is_sack(tp);
738 }
739
740 static inline int tcp_is_fack(const struct tcp_sock *tp)
741 {
742 return tp->rx_opt.sack_ok & 2;
743 }
744
745 static inline void tcp_enable_fack(struct tcp_sock *tp)
746 {
747 tp->rx_opt.sack_ok |= 2;
748 }
749
750 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
751 {
752 return tp->sacked_out + tp->lost_out;
753 }
754
755 /* This determines how many packets are "in the network" to the best
756 * of our knowledge. In many cases it is conservative, but where
757 * detailed information is available from the receiver (via SACK
758 * blocks etc.) we can make more aggressive calculations.
759 *
760 * Use this for decisions involving congestion control, use just
761 * tp->packets_out to determine if the send queue is empty or not.
762 *
763 * Read this equation as:
764 *
765 * "Packets sent once on transmission queue" MINUS
766 * "Packets left network, but not honestly ACKed yet" PLUS
767 * "Packets fast retransmitted"
768 */
769 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
770 {
771 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
772 }
773
774 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
775 * The exception is rate halving phase, when cwnd is decreasing towards
776 * ssthresh.
777 */
778 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
779 {
780 const struct tcp_sock *tp = tcp_sk(sk);
781 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
782 return tp->snd_ssthresh;
783 else
784 return max(tp->snd_ssthresh,
785 ((tp->snd_cwnd >> 1) +
786 (tp->snd_cwnd >> 2)));
787 }
788
789 /* Use define here intentionally to get WARN_ON location shown at the caller */
790 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
791
792 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
793 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
794
795 /* Slow start with delack produces 3 packets of burst, so that
796 * it is safe "de facto". This will be the default - same as
797 * the default reordering threshold - but if reordering increases,
798 * we must be able to allow cwnd to burst at least this much in order
799 * to not pull it back when holes are filled.
800 */
801 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
802 {
803 return tp->reordering;
804 }
805
806 /* Returns end sequence number of the receiver's advertised window */
807 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
808 {
809 return tp->snd_una + tp->snd_wnd;
810 }
811 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
812
813 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
814 const struct sk_buff *skb)
815 {
816 if (skb->len < mss)
817 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
818 }
819
820 static inline void tcp_check_probe_timer(struct sock *sk)
821 {
822 struct tcp_sock *tp = tcp_sk(sk);
823 const struct inet_connection_sock *icsk = inet_csk(sk);
824
825 if (!tp->packets_out && !icsk->icsk_pending)
826 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
827 icsk->icsk_rto, TCP_RTO_MAX);
828 }
829
830 static inline void tcp_push_pending_frames(struct sock *sk)
831 {
832 struct tcp_sock *tp = tcp_sk(sk);
833
834 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle);
835 }
836
837 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)
838 {
839 tp->snd_wl1 = seq;
840 }
841
842 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq)
843 {
844 tp->snd_wl1 = seq;
845 }
846
847 /*
848 * Calculate(/check) TCP checksum
849 */
850 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
851 __be32 daddr, __wsum base)
852 {
853 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
854 }
855
856 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
857 {
858 return __skb_checksum_complete(skb);
859 }
860
861 static inline int tcp_checksum_complete(struct sk_buff *skb)
862 {
863 return !skb_csum_unnecessary(skb) &&
864 __tcp_checksum_complete(skb);
865 }
866
867 /* Prequeue for VJ style copy to user, combined with checksumming. */
868
869 static inline void tcp_prequeue_init(struct tcp_sock *tp)
870 {
871 tp->ucopy.task = NULL;
872 tp->ucopy.len = 0;
873 tp->ucopy.memory = 0;
874 skb_queue_head_init(&tp->ucopy.prequeue);
875 #ifdef CONFIG_NET_DMA
876 tp->ucopy.dma_chan = NULL;
877 tp->ucopy.wakeup = 0;
878 tp->ucopy.pinned_list = NULL;
879 tp->ucopy.dma_cookie = 0;
880 #endif
881 }
882
883 /* Packet is added to VJ-style prequeue for processing in process
884 * context, if a reader task is waiting. Apparently, this exciting
885 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
886 * failed somewhere. Latency? Burstiness? Well, at least now we will
887 * see, why it failed. 8)8) --ANK
888 *
889 * NOTE: is this not too big to inline?
890 */
891 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
892 {
893 struct tcp_sock *tp = tcp_sk(sk);
894
895 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
896 __skb_queue_tail(&tp->ucopy.prequeue, skb);
897 tp->ucopy.memory += skb->truesize;
898 if (tp->ucopy.memory > sk->sk_rcvbuf) {
899 struct sk_buff *skb1;
900
901 BUG_ON(sock_owned_by_user(sk));
902
903 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
904 sk_backlog_rcv(sk, skb1);
905 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPREQUEUEDROPPED);
906 }
907
908 tp->ucopy.memory = 0;
909 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
910 wake_up_interruptible(sk->sk_sleep);
911 if (!inet_csk_ack_scheduled(sk))
912 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
913 (3 * TCP_RTO_MIN) / 4,
914 TCP_RTO_MAX);
915 }
916 return 1;
917 }
918 return 0;
919 }
920
921
922 #undef STATE_TRACE
923
924 #ifdef STATE_TRACE
925 static const char *statename[]={
926 "Unused","Established","Syn Sent","Syn Recv",
927 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
928 "Close Wait","Last ACK","Listen","Closing"
929 };
930 #endif
931 extern void tcp_set_state(struct sock *sk, int state);
932
933 extern void tcp_done(struct sock *sk);
934
935 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
936 {
937 rx_opt->dsack = 0;
938 rx_opt->num_sacks = 0;
939 }
940
941 /* Determine a window scaling and initial window to offer. */
942 extern void tcp_select_initial_window(int __space, __u32 mss,
943 __u32 *rcv_wnd, __u32 *window_clamp,
944 int wscale_ok, __u8 *rcv_wscale);
945
946 static inline int tcp_win_from_space(int space)
947 {
948 return sysctl_tcp_adv_win_scale<=0 ?
949 (space>>(-sysctl_tcp_adv_win_scale)) :
950 space - (space>>sysctl_tcp_adv_win_scale);
951 }
952
953 /* Note: caller must be prepared to deal with negative returns */
954 static inline int tcp_space(const struct sock *sk)
955 {
956 return tcp_win_from_space(sk->sk_rcvbuf -
957 atomic_read(&sk->sk_rmem_alloc));
958 }
959
960 static inline int tcp_full_space(const struct sock *sk)
961 {
962 return tcp_win_from_space(sk->sk_rcvbuf);
963 }
964
965 static inline void tcp_openreq_init(struct request_sock *req,
966 struct tcp_options_received *rx_opt,
967 struct sk_buff *skb)
968 {
969 struct inet_request_sock *ireq = inet_rsk(req);
970
971 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
972 req->cookie_ts = 0;
973 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
974 req->mss = rx_opt->mss_clamp;
975 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
976 ireq->tstamp_ok = rx_opt->tstamp_ok;
977 ireq->sack_ok = rx_opt->sack_ok;
978 ireq->snd_wscale = rx_opt->snd_wscale;
979 ireq->wscale_ok = rx_opt->wscale_ok;
980 ireq->acked = 0;
981 ireq->ecn_ok = 0;
982 ireq->rmt_port = tcp_hdr(skb)->source;
983 ireq->loc_port = tcp_hdr(skb)->dest;
984 }
985
986 extern void tcp_enter_memory_pressure(struct sock *sk);
987
988 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
989 {
990 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
991 }
992
993 static inline int keepalive_time_when(const struct tcp_sock *tp)
994 {
995 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
996 }
997
998 static inline int tcp_fin_time(const struct sock *sk)
999 {
1000 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1001 const int rto = inet_csk(sk)->icsk_rto;
1002
1003 if (fin_timeout < (rto << 2) - (rto >> 1))
1004 fin_timeout = (rto << 2) - (rto >> 1);
1005
1006 return fin_timeout;
1007 }
1008
1009 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt,
1010 int paws_win)
1011 {
1012 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
1013 return 1;
1014 if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))
1015 return 1;
1016
1017 return 0;
1018 }
1019
1020 static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt,
1021 int rst)
1022 {
1023 if (tcp_paws_check(rx_opt, 0))
1024 return 0;
1025
1026 /* RST segments are not recommended to carry timestamp,
1027 and, if they do, it is recommended to ignore PAWS because
1028 "their cleanup function should take precedence over timestamps."
1029 Certainly, it is mistake. It is necessary to understand the reasons
1030 of this constraint to relax it: if peer reboots, clock may go
1031 out-of-sync and half-open connections will not be reset.
1032 Actually, the problem would be not existing if all
1033 the implementations followed draft about maintaining clock
1034 via reboots. Linux-2.2 DOES NOT!
1035
1036 However, we can relax time bounds for RST segments to MSL.
1037 */
1038 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1039 return 0;
1040 return 1;
1041 }
1042
1043 #define TCP_CHECK_TIMER(sk) do { } while (0)
1044
1045 static inline void tcp_mib_init(struct net *net)
1046 {
1047 /* See RFC 2012 */
1048 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
1049 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1050 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1051 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
1052 }
1053
1054 /* from STCP */
1055 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1056 {
1057 tp->lost_skb_hint = NULL;
1058 tp->scoreboard_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 tp->retransmit_skb_hint = NULL;
1065 }
1066
1067 /* MD5 Signature */
1068 struct crypto_hash;
1069
1070 /* - key database */
1071 struct tcp_md5sig_key {
1072 u8 *key;
1073 u8 keylen;
1074 };
1075
1076 struct tcp4_md5sig_key {
1077 struct tcp_md5sig_key base;
1078 __be32 addr;
1079 };
1080
1081 struct tcp6_md5sig_key {
1082 struct tcp_md5sig_key base;
1083 #if 0
1084 u32 scope_id; /* XXX */
1085 #endif
1086 struct in6_addr addr;
1087 };
1088
1089 /* - sock block */
1090 struct tcp_md5sig_info {
1091 struct tcp4_md5sig_key *keys4;
1092 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1093 struct tcp6_md5sig_key *keys6;
1094 u32 entries6;
1095 u32 alloced6;
1096 #endif
1097 u32 entries4;
1098 u32 alloced4;
1099 };
1100
1101 /* - pseudo header */
1102 struct tcp4_pseudohdr {
1103 __be32 saddr;
1104 __be32 daddr;
1105 __u8 pad;
1106 __u8 protocol;
1107 __be16 len;
1108 };
1109
1110 struct tcp6_pseudohdr {
1111 struct in6_addr saddr;
1112 struct in6_addr daddr;
1113 __be32 len;
1114 __be32 protocol; /* including padding */
1115 };
1116
1117 union tcp_md5sum_block {
1118 struct tcp4_pseudohdr ip4;
1119 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1120 struct tcp6_pseudohdr ip6;
1121 #endif
1122 };
1123
1124 /* - pool: digest algorithm, hash description and scratch buffer */
1125 struct tcp_md5sig_pool {
1126 struct hash_desc md5_desc;
1127 union tcp_md5sum_block md5_blk;
1128 };
1129
1130 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1131
1132 /* - functions */
1133 extern int tcp_v4_md5_hash_skb(char *md5_hash,
1134 struct tcp_md5sig_key *key,
1135 struct sock *sk,
1136 struct request_sock *req,
1137 struct sk_buff *skb);
1138
1139 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1140 struct sock *addr_sk);
1141
1142 extern int tcp_v4_md5_do_add(struct sock *sk,
1143 __be32 addr,
1144 u8 *newkey,
1145 u8 newkeylen);
1146
1147 extern int tcp_v4_md5_do_del(struct sock *sk,
1148 __be32 addr);
1149
1150 #ifdef CONFIG_TCP_MD5SIG
1151 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1152 &(struct tcp_md5sig_key) { \
1153 .key = (twsk)->tw_md5_key, \
1154 .keylen = (twsk)->tw_md5_keylen, \
1155 } : NULL)
1156 #else
1157 #define tcp_twsk_md5_key(twsk) NULL
1158 #endif
1159
1160 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1161 extern void tcp_free_md5sig_pool(void);
1162
1163 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1164 extern void __tcp_put_md5sig_pool(void);
1165 extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *);
1166 extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *,
1167 unsigned header_len);
1168 extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1169 struct tcp_md5sig_key *key);
1170
1171 static inline
1172 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1173 {
1174 int cpu = get_cpu();
1175 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1176 if (!ret)
1177 put_cpu();
1178 return ret;
1179 }
1180
1181 static inline void tcp_put_md5sig_pool(void)
1182 {
1183 __tcp_put_md5sig_pool();
1184 put_cpu();
1185 }
1186
1187 /* write queue abstraction */
1188 static inline void tcp_write_queue_purge(struct sock *sk)
1189 {
1190 struct sk_buff *skb;
1191
1192 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1193 sk_wmem_free_skb(sk, skb);
1194 sk_mem_reclaim(sk);
1195 }
1196
1197 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1198 {
1199 return skb_peek(&sk->sk_write_queue);
1200 }
1201
1202 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1203 {
1204 return skb_peek_tail(&sk->sk_write_queue);
1205 }
1206
1207 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1208 {
1209 return skb_queue_next(&sk->sk_write_queue, skb);
1210 }
1211
1212 static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_buff *skb)
1213 {
1214 return skb_queue_prev(&sk->sk_write_queue, skb);
1215 }
1216
1217 #define tcp_for_write_queue(skb, sk) \
1218 skb_queue_walk(&(sk)->sk_write_queue, skb)
1219
1220 #define tcp_for_write_queue_from(skb, sk) \
1221 skb_queue_walk_from(&(sk)->sk_write_queue, skb)
1222
1223 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1224 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
1225
1226 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1227 {
1228 return sk->sk_send_head;
1229 }
1230
1231 static inline bool tcp_skb_is_last(const struct sock *sk,
1232 const struct sk_buff *skb)
1233 {
1234 return skb_queue_is_last(&sk->sk_write_queue, skb);
1235 }
1236
1237 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1238 {
1239 if (tcp_skb_is_last(sk, skb))
1240 sk->sk_send_head = NULL;
1241 else
1242 sk->sk_send_head = tcp_write_queue_next(sk, skb);
1243 }
1244
1245 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1246 {
1247 if (sk->sk_send_head == skb_unlinked)
1248 sk->sk_send_head = NULL;
1249 }
1250
1251 static inline void tcp_init_send_head(struct sock *sk)
1252 {
1253 sk->sk_send_head = NULL;
1254 }
1255
1256 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1257 {
1258 __skb_queue_tail(&sk->sk_write_queue, skb);
1259 }
1260
1261 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1262 {
1263 __tcp_add_write_queue_tail(sk, skb);
1264
1265 /* Queue it, remembering where we must start sending. */
1266 if (sk->sk_send_head == NULL) {
1267 sk->sk_send_head = skb;
1268
1269 if (tcp_sk(sk)->highest_sack == NULL)
1270 tcp_sk(sk)->highest_sack = skb;
1271 }
1272 }
1273
1274 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1275 {
1276 __skb_queue_head(&sk->sk_write_queue, skb);
1277 }
1278
1279 /* Insert buff after skb on the write queue of sk. */
1280 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1281 struct sk_buff *buff,
1282 struct sock *sk)
1283 {
1284 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1285 }
1286
1287 /* Insert new before skb on the write queue of sk. */
1288 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1289 struct sk_buff *skb,
1290 struct sock *sk)
1291 {
1292 __skb_queue_before(&sk->sk_write_queue, skb, new);
1293
1294 if (sk->sk_send_head == skb)
1295 sk->sk_send_head = new;
1296 }
1297
1298 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1299 {
1300 __skb_unlink(skb, &sk->sk_write_queue);
1301 }
1302
1303 static inline int tcp_write_queue_empty(struct sock *sk)
1304 {
1305 return skb_queue_empty(&sk->sk_write_queue);
1306 }
1307
1308 /* Start sequence of the highest skb with SACKed bit, valid only if
1309 * sacked > 0 or when the caller has ensured validity by itself.
1310 */
1311 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1312 {
1313 if (!tp->sacked_out)
1314 return tp->snd_una;
1315
1316 if (tp->highest_sack == NULL)
1317 return tp->snd_nxt;
1318
1319 return TCP_SKB_CB(tp->highest_sack)->seq;
1320 }
1321
1322 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1323 {
1324 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1325 tcp_write_queue_next(sk, skb);
1326 }
1327
1328 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1329 {
1330 return tcp_sk(sk)->highest_sack;
1331 }
1332
1333 static inline void tcp_highest_sack_reset(struct sock *sk)
1334 {
1335 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1336 }
1337
1338 /* Called when old skb is about to be deleted (to be combined with new skb) */
1339 static inline void tcp_highest_sack_combine(struct sock *sk,
1340 struct sk_buff *old,
1341 struct sk_buff *new)
1342 {
1343 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1344 tcp_sk(sk)->highest_sack = new;
1345 }
1346
1347 /* /proc */
1348 enum tcp_seq_states {
1349 TCP_SEQ_STATE_LISTENING,
1350 TCP_SEQ_STATE_OPENREQ,
1351 TCP_SEQ_STATE_ESTABLISHED,
1352 TCP_SEQ_STATE_TIME_WAIT,
1353 };
1354
1355 struct tcp_seq_afinfo {
1356 char *name;
1357 sa_family_t family;
1358 struct file_operations seq_fops;
1359 struct seq_operations seq_ops;
1360 };
1361
1362 struct tcp_iter_state {
1363 struct seq_net_private p;
1364 sa_family_t family;
1365 enum tcp_seq_states state;
1366 struct sock *syn_wait_sk;
1367 int bucket, sbucket, num, uid;
1368 };
1369
1370 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1371 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1372
1373 extern struct request_sock_ops tcp_request_sock_ops;
1374 extern struct request_sock_ops tcp6_request_sock_ops;
1375
1376 extern void tcp_v4_destroy_sock(struct sock *sk);
1377
1378 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1379 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1380 extern struct sk_buff **tcp_gro_receive(struct sk_buff **head,
1381 struct sk_buff *skb);
1382 extern struct sk_buff **tcp4_gro_receive(struct sk_buff **head,
1383 struct sk_buff *skb);
1384 extern int tcp_gro_complete(struct sk_buff *skb);
1385 extern int tcp4_gro_complete(struct sk_buff *skb);
1386
1387 #ifdef CONFIG_PROC_FS
1388 extern int tcp4_proc_init(void);
1389 extern void tcp4_proc_exit(void);
1390 #endif
1391
1392 /* TCP af-specific functions */
1393 struct tcp_sock_af_ops {
1394 #ifdef CONFIG_TCP_MD5SIG
1395 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1396 struct sock *addr_sk);
1397 int (*calc_md5_hash) (char *location,
1398 struct tcp_md5sig_key *md5,
1399 struct sock *sk,
1400 struct request_sock *req,
1401 struct sk_buff *skb);
1402 int (*md5_add) (struct sock *sk,
1403 struct sock *addr_sk,
1404 u8 *newkey,
1405 u8 len);
1406 int (*md5_parse) (struct sock *sk,
1407 char __user *optval,
1408 int optlen);
1409 #endif
1410 };
1411
1412 struct tcp_request_sock_ops {
1413 #ifdef CONFIG_TCP_MD5SIG
1414 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1415 struct request_sock *req);
1416 #endif
1417 };
1418
1419 extern void tcp_v4_init(void);
1420 extern void tcp_init(void);
1421
1422 #endif /* _TCP_H */
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