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[TCP]: Left out sync->verify (the new meaning of it) & definify
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / net / tcp.h
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Definitions for the TCP module.
7 *
8 * Version: @(#)tcp.h 1.0.5 05/23/93
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
17 */
18 #ifndef _TCP_H
19 #define _TCP_H
20
21 #define TCP_DEBUG 1
22 #define FASTRETRANS_DEBUG 1
23
24 #include <linux/list.h>
25 #include <linux/tcp.h>
26 #include <linux/slab.h>
27 #include <linux/cache.h>
28 #include <linux/percpu.h>
29 #include <linux/skbuff.h>
30 #include <linux/dmaengine.h>
31 #include <linux/crypto.h>
32
33 #include <net/inet_connection_sock.h>
34 #include <net/inet_timewait_sock.h>
35 #include <net/inet_hashtables.h>
36 #include <net/checksum.h>
37 #include <net/request_sock.h>
38 #include <net/sock.h>
39 #include <net/snmp.h>
40 #include <net/ip.h>
41 #include <net/tcp_states.h>
42 #include <net/inet_ecn.h>
43
44 #include <linux/seq_file.h>
45
46 extern struct inet_hashinfo tcp_hashinfo;
47
48 extern atomic_t tcp_orphan_count;
49 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
50
51 #define MAX_TCP_HEADER (128 + MAX_HEADER)
52
53 /*
54 * Never offer a window over 32767 without using window scaling. Some
55 * poor stacks do signed 16bit maths!
56 */
57 #define MAX_TCP_WINDOW 32767U
58
59 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
60 #define TCP_MIN_MSS 88U
61
62 /* Minimal RCV_MSS. */
63 #define TCP_MIN_RCVMSS 536U
64
65 /* The least MTU to use for probing */
66 #define TCP_BASE_MSS 512
67
68 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
69 #define TCP_FASTRETRANS_THRESH 3
70
71 /* Maximal reordering. */
72 #define TCP_MAX_REORDERING 127
73
74 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
75 #define TCP_MAX_QUICKACKS 16U
76
77 /* urg_data states */
78 #define TCP_URG_VALID 0x0100
79 #define TCP_URG_NOTYET 0x0200
80 #define TCP_URG_READ 0x0400
81
82 #define TCP_RETR1 3 /*
83 * This is how many retries it does before it
84 * tries to figure out if the gateway is
85 * down. Minimal RFC value is 3; it corresponds
86 * to ~3sec-8min depending on RTO.
87 */
88
89 #define TCP_RETR2 15 /*
90 * This should take at least
91 * 90 minutes to time out.
92 * RFC1122 says that the limit is 100 sec.
93 * 15 is ~13-30min depending on RTO.
94 */
95
96 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
97 * connection: ~180sec is RFC minimum */
98
99 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
100 * connection: ~180sec is RFC minimum */
101
102
103 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
104 * socket. 7 is ~50sec-16min.
105 */
106
107
108 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
109 * state, about 60 seconds */
110 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
111 /* BSD style FIN_WAIT2 deadlock breaker.
112 * It used to be 3min, new value is 60sec,
113 * to combine FIN-WAIT-2 timeout with
114 * TIME-WAIT timer.
115 */
116
117 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
118 #if HZ >= 100
119 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
120 #define TCP_ATO_MIN ((unsigned)(HZ/25))
121 #else
122 #define TCP_DELACK_MIN 4U
123 #define TCP_ATO_MIN 4U
124 #endif
125 #define TCP_RTO_MAX ((unsigned)(120*HZ))
126 #define TCP_RTO_MIN ((unsigned)(HZ/5))
127 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
128
129 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
130 * for local resources.
131 */
132
133 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
134 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
135 #define TCP_KEEPALIVE_INTVL (75*HZ)
136
137 #define MAX_TCP_KEEPIDLE 32767
138 #define MAX_TCP_KEEPINTVL 32767
139 #define MAX_TCP_KEEPCNT 127
140 #define MAX_TCP_SYNCNT 127
141
142 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
143
144 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
145 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
146 * after this time. It should be equal
147 * (or greater than) TCP_TIMEWAIT_LEN
148 * to provide reliability equal to one
149 * provided by timewait state.
150 */
151 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
152 * timestamps. It must be less than
153 * minimal timewait lifetime.
154 */
155 /*
156 * TCP option
157 */
158
159 #define TCPOPT_NOP 1 /* Padding */
160 #define TCPOPT_EOL 0 /* End of options */
161 #define TCPOPT_MSS 2 /* Segment size negotiating */
162 #define TCPOPT_WINDOW 3 /* Window scaling */
163 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
164 #define TCPOPT_SACK 5 /* SACK Block */
165 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
166 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
167
168 /*
169 * TCP option lengths
170 */
171
172 #define TCPOLEN_MSS 4
173 #define TCPOLEN_WINDOW 3
174 #define TCPOLEN_SACK_PERM 2
175 #define TCPOLEN_TIMESTAMP 10
176 #define TCPOLEN_MD5SIG 18
177
178 /* But this is what stacks really send out. */
179 #define TCPOLEN_TSTAMP_ALIGNED 12
180 #define TCPOLEN_WSCALE_ALIGNED 4
181 #define TCPOLEN_SACKPERM_ALIGNED 4
182 #define TCPOLEN_SACK_BASE 2
183 #define TCPOLEN_SACK_BASE_ALIGNED 4
184 #define TCPOLEN_SACK_PERBLOCK 8
185 #define TCPOLEN_MD5SIG_ALIGNED 20
186
187 /* Flags in tp->nonagle */
188 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
189 #define TCP_NAGLE_CORK 2 /* Socket is corked */
190 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
191
192 extern struct inet_timewait_death_row tcp_death_row;
193
194 /* sysctl variables for tcp */
195 extern int sysctl_tcp_timestamps;
196 extern int sysctl_tcp_window_scaling;
197 extern int sysctl_tcp_sack;
198 extern int sysctl_tcp_fin_timeout;
199 extern int sysctl_tcp_keepalive_time;
200 extern int sysctl_tcp_keepalive_probes;
201 extern int sysctl_tcp_keepalive_intvl;
202 extern int sysctl_tcp_syn_retries;
203 extern int sysctl_tcp_synack_retries;
204 extern int sysctl_tcp_retries1;
205 extern int sysctl_tcp_retries2;
206 extern int sysctl_tcp_orphan_retries;
207 extern int sysctl_tcp_syncookies;
208 extern int sysctl_tcp_retrans_collapse;
209 extern int sysctl_tcp_stdurg;
210 extern int sysctl_tcp_rfc1337;
211 extern int sysctl_tcp_abort_on_overflow;
212 extern int sysctl_tcp_max_orphans;
213 extern int sysctl_tcp_fack;
214 extern int sysctl_tcp_reordering;
215 extern int sysctl_tcp_ecn;
216 extern int sysctl_tcp_dsack;
217 extern int sysctl_tcp_mem[3];
218 extern int sysctl_tcp_wmem[3];
219 extern int sysctl_tcp_rmem[3];
220 extern int sysctl_tcp_app_win;
221 extern int sysctl_tcp_adv_win_scale;
222 extern int sysctl_tcp_tw_reuse;
223 extern int sysctl_tcp_frto;
224 extern int sysctl_tcp_frto_response;
225 extern int sysctl_tcp_low_latency;
226 extern int sysctl_tcp_dma_copybreak;
227 extern int sysctl_tcp_nometrics_save;
228 extern int sysctl_tcp_moderate_rcvbuf;
229 extern int sysctl_tcp_tso_win_divisor;
230 extern int sysctl_tcp_abc;
231 extern int sysctl_tcp_mtu_probing;
232 extern int sysctl_tcp_base_mss;
233 extern int sysctl_tcp_workaround_signed_windows;
234 extern int sysctl_tcp_slow_start_after_idle;
235 extern int sysctl_tcp_max_ssthresh;
236
237 extern atomic_t tcp_memory_allocated;
238 extern atomic_t tcp_sockets_allocated;
239 extern int tcp_memory_pressure;
240
241 /*
242 * The next routines deal with comparing 32 bit unsigned ints
243 * and worry about wraparound (automatic with unsigned arithmetic).
244 */
245
246 static inline int before(__u32 seq1, __u32 seq2)
247 {
248 return (__s32)(seq1-seq2) < 0;
249 }
250 #define after(seq2, seq1) before(seq1, seq2)
251
252 /* is s2<=s1<=s3 ? */
253 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
254 {
255 return seq3 - seq2 >= seq1 - seq2;
256 }
257
258 static inline int tcp_too_many_orphans(struct sock *sk, int num)
259 {
260 return (num > sysctl_tcp_max_orphans) ||
261 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
262 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
263 }
264
265 extern struct proto tcp_prot;
266
267 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
268 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
269 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
270 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
271 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
272 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
273 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(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 static inline void tcp_dec_quickack_mode(struct sock *sk,
313 const unsigned int pkts)
314 {
315 struct inet_connection_sock *icsk = inet_csk(sk);
316
317 if (icsk->icsk_ack.quick) {
318 if (pkts >= icsk->icsk_ack.quick) {
319 icsk->icsk_ack.quick = 0;
320 /* Leaving quickack mode we deflate ATO. */
321 icsk->icsk_ack.ato = TCP_ATO_MIN;
322 } else
323 icsk->icsk_ack.quick -= pkts;
324 }
325 }
326
327 extern void tcp_enter_quickack_mode(struct sock *sk);
328
329 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
330 {
331 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
332 }
333
334 #define TCP_ECN_OK 1
335 #define TCP_ECN_QUEUE_CWR 2
336 #define TCP_ECN_DEMAND_CWR 4
337
338 static __inline__ void
339 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
340 {
341 if (sysctl_tcp_ecn && th->ece && th->cwr)
342 inet_rsk(req)->ecn_ok = 1;
343 }
344
345 enum tcp_tw_status
346 {
347 TCP_TW_SUCCESS = 0,
348 TCP_TW_RST = 1,
349 TCP_TW_ACK = 2,
350 TCP_TW_SYN = 3
351 };
352
353
354 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
355 struct sk_buff *skb,
356 const struct tcphdr *th);
357
358 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
359 struct request_sock *req,
360 struct request_sock **prev);
361 extern int tcp_child_process(struct sock *parent,
362 struct sock *child,
363 struct sk_buff *skb);
364 extern int tcp_use_frto(struct sock *sk);
365 extern void tcp_enter_frto(struct sock *sk);
366 extern void tcp_enter_loss(struct sock *sk, int how);
367 extern void tcp_clear_retrans(struct tcp_sock *tp);
368 extern void tcp_update_metrics(struct sock *sk);
369
370 extern void tcp_close(struct sock *sk,
371 long timeout);
372 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
373
374 extern int tcp_getsockopt(struct sock *sk, int level,
375 int optname,
376 char __user *optval,
377 int __user *optlen);
378 extern int tcp_setsockopt(struct sock *sk, int level,
379 int optname, char __user *optval,
380 int optlen);
381 extern int compat_tcp_getsockopt(struct sock *sk,
382 int level, int optname,
383 char __user *optval, int __user *optlen);
384 extern int compat_tcp_setsockopt(struct sock *sk,
385 int level, int optname,
386 char __user *optval, int optlen);
387 extern void tcp_set_keepalive(struct sock *sk, int val);
388 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
389 struct msghdr *msg,
390 size_t len, int nonblock,
391 int flags, int *addr_len);
392
393 extern void tcp_parse_options(struct sk_buff *skb,
394 struct tcp_options_received *opt_rx,
395 int estab);
396
397 /*
398 * TCP v4 functions exported for the inet6 API
399 */
400
401 extern void tcp_v4_send_check(struct sock *sk, int len,
402 struct sk_buff *skb);
403
404 extern int tcp_v4_conn_request(struct sock *sk,
405 struct sk_buff *skb);
406
407 extern struct sock * tcp_create_openreq_child(struct sock *sk,
408 struct request_sock *req,
409 struct sk_buff *skb);
410
411 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
412 struct sk_buff *skb,
413 struct request_sock *req,
414 struct dst_entry *dst);
415
416 extern int tcp_v4_do_rcv(struct sock *sk,
417 struct sk_buff *skb);
418
419 extern int tcp_v4_connect(struct sock *sk,
420 struct sockaddr *uaddr,
421 int addr_len);
422
423 extern int tcp_connect(struct sock *sk);
424
425 extern struct sk_buff * tcp_make_synack(struct sock *sk,
426 struct dst_entry *dst,
427 struct request_sock *req);
428
429 extern int tcp_disconnect(struct sock *sk, int flags);
430
431 extern void tcp_unhash(struct sock *sk);
432
433 /* From syncookies.c */
434 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
435 struct ip_options *opt);
436 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
437 __u16 *mss);
438
439 /* tcp_output.c */
440
441 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
442 int nonagle);
443 extern int tcp_may_send_now(struct sock *sk);
444 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
445 extern void tcp_xmit_retransmit_queue(struct sock *);
446 extern void tcp_simple_retransmit(struct sock *);
447 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
448 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
449
450 extern void tcp_send_probe0(struct sock *);
451 extern void tcp_send_partial(struct sock *);
452 extern int tcp_write_wakeup(struct sock *);
453 extern void tcp_send_fin(struct sock *sk);
454 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
455 extern int tcp_send_synack(struct sock *);
456 extern void tcp_push_one(struct sock *, unsigned int mss_now);
457 extern void tcp_send_ack(struct sock *sk);
458 extern void tcp_send_delayed_ack(struct sock *sk);
459
460 /* tcp_input.c */
461 extern void tcp_cwnd_application_limited(struct sock *sk);
462
463 /* tcp_timer.c */
464 extern void tcp_init_xmit_timers(struct sock *);
465 static inline void tcp_clear_xmit_timers(struct sock *sk)
466 {
467 inet_csk_clear_xmit_timers(sk);
468 }
469
470 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
471 extern unsigned int tcp_current_mss(struct sock *sk, int large);
472
473 /* tcp.c */
474 extern void tcp_get_info(struct sock *, struct tcp_info *);
475
476 /* Read 'sendfile()'-style from a TCP socket */
477 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
478 unsigned int, size_t);
479 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
480 sk_read_actor_t recv_actor);
481
482 extern void tcp_initialize_rcv_mss(struct sock *sk);
483
484 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
485 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
486 extern void tcp_mtup_init(struct sock *sk);
487
488 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
489 {
490 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
491 ntohl(TCP_FLAG_ACK) |
492 snd_wnd);
493 }
494
495 static inline void tcp_fast_path_on(struct tcp_sock *tp)
496 {
497 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
498 }
499
500 static inline void tcp_fast_path_check(struct sock *sk)
501 {
502 struct tcp_sock *tp = tcp_sk(sk);
503
504 if (skb_queue_empty(&tp->out_of_order_queue) &&
505 tp->rcv_wnd &&
506 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
507 !tp->urg_data)
508 tcp_fast_path_on(tp);
509 }
510
511 /* Compute the actual receive window we are currently advertising.
512 * Rcv_nxt can be after the window if our peer push more data
513 * than the offered window.
514 */
515 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
516 {
517 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
518
519 if (win < 0)
520 win = 0;
521 return (u32) win;
522 }
523
524 /* Choose a new window, without checks for shrinking, and without
525 * scaling applied to the result. The caller does these things
526 * if necessary. This is a "raw" window selection.
527 */
528 extern u32 __tcp_select_window(struct sock *sk);
529
530 /* TCP timestamps are only 32-bits, this causes a slight
531 * complication on 64-bit systems since we store a snapshot
532 * of jiffies in the buffer control blocks below. We decided
533 * to use only the low 32-bits of jiffies and hide the ugly
534 * casts with the following macro.
535 */
536 #define tcp_time_stamp ((__u32)(jiffies))
537
538 /* This is what the send packet queuing engine uses to pass
539 * TCP per-packet control information to the transmission
540 * code. We also store the host-order sequence numbers in
541 * here too. This is 36 bytes on 32-bit architectures,
542 * 40 bytes on 64-bit machines, if this grows please adjust
543 * skbuff.h:skbuff->cb[xxx] size appropriately.
544 */
545 struct tcp_skb_cb {
546 union {
547 struct inet_skb_parm h4;
548 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
549 struct inet6_skb_parm h6;
550 #endif
551 } header; /* For incoming frames */
552 __u32 seq; /* Starting sequence number */
553 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
554 __u32 when; /* used to compute rtt's */
555 __u8 flags; /* TCP header flags. */
556
557 /* NOTE: These must match up to the flags byte in a
558 * real TCP header.
559 */
560 #define TCPCB_FLAG_FIN 0x01
561 #define TCPCB_FLAG_SYN 0x02
562 #define TCPCB_FLAG_RST 0x04
563 #define TCPCB_FLAG_PSH 0x08
564 #define TCPCB_FLAG_ACK 0x10
565 #define TCPCB_FLAG_URG 0x20
566 #define TCPCB_FLAG_ECE 0x40
567 #define TCPCB_FLAG_CWR 0x80
568
569 __u8 sacked; /* State flags for SACK/FACK. */
570 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
571 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
572 #define TCPCB_LOST 0x04 /* SKB is lost */
573 #define TCPCB_TAGBITS 0x07 /* All tag bits */
574
575 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
576 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
577
578 #define TCPCB_URG 0x20 /* Urgent pointer advanced here */
579
580 #define TCPCB_AT_TAIL (TCPCB_URG)
581
582 __u16 urg_ptr; /* Valid w/URG flags is set. */
583 __u32 ack_seq; /* Sequence number ACK'd */
584 };
585
586 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
587
588 /* Due to TSO, an SKB can be composed of multiple actual
589 * packets. To keep these tracked properly, we use this.
590 */
591 static inline int tcp_skb_pcount(const struct sk_buff *skb)
592 {
593 return skb_shinfo(skb)->gso_segs;
594 }
595
596 /* This is valid iff tcp_skb_pcount() > 1. */
597 static inline int tcp_skb_mss(const struct sk_buff *skb)
598 {
599 return skb_shinfo(skb)->gso_size;
600 }
601
602 static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
603 {
604 if (*count) {
605 *count -= decr;
606 if ((int)*count < 0)
607 *count = 0;
608 }
609 }
610
611 static inline void tcp_dec_pcount_approx(__u32 *count,
612 const struct sk_buff *skb)
613 {
614 tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
615 }
616
617 static inline void tcp_packets_out_inc(struct sock *sk,
618 const struct sk_buff *skb)
619 {
620 struct tcp_sock *tp = tcp_sk(sk);
621 int orig = tp->packets_out;
622
623 tp->packets_out += tcp_skb_pcount(skb);
624 if (!orig)
625 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
626 inet_csk(sk)->icsk_rto, TCP_RTO_MAX);
627 }
628
629 static inline void tcp_packets_out_dec(struct tcp_sock *tp,
630 const struct sk_buff *skb)
631 {
632 tp->packets_out -= tcp_skb_pcount(skb);
633 }
634
635 /* Events passed to congestion control interface */
636 enum tcp_ca_event {
637 CA_EVENT_TX_START, /* first transmit when no packets in flight */
638 CA_EVENT_CWND_RESTART, /* congestion window restart */
639 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
640 CA_EVENT_FRTO, /* fast recovery timeout */
641 CA_EVENT_LOSS, /* loss timeout */
642 CA_EVENT_FAST_ACK, /* in sequence ack */
643 CA_EVENT_SLOW_ACK, /* other ack */
644 };
645
646 /*
647 * Interface for adding new TCP congestion control handlers
648 */
649 #define TCP_CA_NAME_MAX 16
650 #define TCP_CA_MAX 128
651 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
652
653 #define TCP_CONG_NON_RESTRICTED 0x1
654 #define TCP_CONG_RTT_STAMP 0x2
655
656 struct tcp_congestion_ops {
657 struct list_head list;
658 unsigned long flags;
659
660 /* initialize private data (optional) */
661 void (*init)(struct sock *sk);
662 /* cleanup private data (optional) */
663 void (*release)(struct sock *sk);
664
665 /* return slow start threshold (required) */
666 u32 (*ssthresh)(struct sock *sk);
667 /* lower bound for congestion window (optional) */
668 u32 (*min_cwnd)(const struct sock *sk);
669 /* do new cwnd calculation (required) */
670 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight, int good_ack);
671 /* call before changing ca_state (optional) */
672 void (*set_state)(struct sock *sk, u8 new_state);
673 /* call when cwnd event occurs (optional) */
674 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
675 /* new value of cwnd after loss (optional) */
676 u32 (*undo_cwnd)(struct sock *sk);
677 /* hook for packet ack accounting (optional) */
678 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
679 /* get info for inet_diag (optional) */
680 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
681
682 char name[TCP_CA_NAME_MAX];
683 struct module *owner;
684 };
685
686 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
687 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
688
689 extern void tcp_init_congestion_control(struct sock *sk);
690 extern void tcp_cleanup_congestion_control(struct sock *sk);
691 extern int tcp_set_default_congestion_control(const char *name);
692 extern void tcp_get_default_congestion_control(char *name);
693 extern void tcp_get_available_congestion_control(char *buf, size_t len);
694 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
695 extern int tcp_set_allowed_congestion_control(char *allowed);
696 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
697 extern void tcp_slow_start(struct tcp_sock *tp);
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, int flag);
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 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
723 {
724 return tp->sacked_out + tp->lost_out;
725 }
726
727 /* This determines how many packets are "in the network" to the best
728 * of our knowledge. In many cases it is conservative, but where
729 * detailed information is available from the receiver (via SACK
730 * blocks etc.) we can make more aggressive calculations.
731 *
732 * Use this for decisions involving congestion control, use just
733 * tp->packets_out to determine if the send queue is empty or not.
734 *
735 * Read this equation as:
736 *
737 * "Packets sent once on transmission queue" MINUS
738 * "Packets left network, but not honestly ACKed yet" PLUS
739 * "Packets fast retransmitted"
740 */
741 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
742 {
743 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
744 }
745
746 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
747 * The exception is rate halving phase, when cwnd is decreasing towards
748 * ssthresh.
749 */
750 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
751 {
752 const struct tcp_sock *tp = tcp_sk(sk);
753 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
754 return tp->snd_ssthresh;
755 else
756 return max(tp->snd_ssthresh,
757 ((tp->snd_cwnd >> 1) +
758 (tp->snd_cwnd >> 2)));
759 }
760
761 /* Use define here intentionally to get BUG_ON location shown at the caller */
762 #define tcp_verify_left_out(tp) \
763 BUG_ON(tp->rx_opt.sack_ok && (tcp_left_out(tp) > tp->packets_out))
764
765 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
766 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
767
768 /* Slow start with delack produces 3 packets of burst, so that
769 * it is safe "de facto".
770 */
771 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
772 {
773 return 3;
774 }
775
776 /* RFC2861 Check whether we are limited by application or congestion window
777 * This is the inverse of cwnd check in tcp_tso_should_defer
778 */
779 static inline int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight)
780 {
781 const struct tcp_sock *tp = tcp_sk(sk);
782 u32 left;
783
784 if (in_flight >= tp->snd_cwnd)
785 return 1;
786
787 if (!sk_can_gso(sk))
788 return 0;
789
790 left = tp->snd_cwnd - in_flight;
791 if (sysctl_tcp_tso_win_divisor)
792 return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd;
793 else
794 return left <= tcp_max_burst(tp);
795 }
796
797 static inline void tcp_minshall_update(struct tcp_sock *tp, int mss,
798 const struct sk_buff *skb)
799 {
800 if (skb->len < mss)
801 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
802 }
803
804 static inline void tcp_check_probe_timer(struct sock *sk)
805 {
806 struct tcp_sock *tp = tcp_sk(sk);
807 const struct inet_connection_sock *icsk = inet_csk(sk);
808
809 if (!tp->packets_out && !icsk->icsk_pending)
810 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
811 icsk->icsk_rto, TCP_RTO_MAX);
812 }
813
814 static inline void tcp_push_pending_frames(struct sock *sk)
815 {
816 struct tcp_sock *tp = tcp_sk(sk);
817
818 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
819 }
820
821 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
822 {
823 tp->snd_wl1 = seq;
824 }
825
826 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
827 {
828 tp->snd_wl1 = seq;
829 }
830
831 /*
832 * Calculate(/check) TCP checksum
833 */
834 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
835 __be32 daddr, __wsum base)
836 {
837 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
838 }
839
840 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
841 {
842 return __skb_checksum_complete(skb);
843 }
844
845 static inline int tcp_checksum_complete(struct sk_buff *skb)
846 {
847 return !skb_csum_unnecessary(skb) &&
848 __tcp_checksum_complete(skb);
849 }
850
851 /* Prequeue for VJ style copy to user, combined with checksumming. */
852
853 static inline void tcp_prequeue_init(struct tcp_sock *tp)
854 {
855 tp->ucopy.task = NULL;
856 tp->ucopy.len = 0;
857 tp->ucopy.memory = 0;
858 skb_queue_head_init(&tp->ucopy.prequeue);
859 #ifdef CONFIG_NET_DMA
860 tp->ucopy.dma_chan = NULL;
861 tp->ucopy.wakeup = 0;
862 tp->ucopy.pinned_list = NULL;
863 tp->ucopy.dma_cookie = 0;
864 #endif
865 }
866
867 /* Packet is added to VJ-style prequeue for processing in process
868 * context, if a reader task is waiting. Apparently, this exciting
869 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
870 * failed somewhere. Latency? Burstiness? Well, at least now we will
871 * see, why it failed. 8)8) --ANK
872 *
873 * NOTE: is this not too big to inline?
874 */
875 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
876 {
877 struct tcp_sock *tp = tcp_sk(sk);
878
879 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
880 __skb_queue_tail(&tp->ucopy.prequeue, skb);
881 tp->ucopy.memory += skb->truesize;
882 if (tp->ucopy.memory > sk->sk_rcvbuf) {
883 struct sk_buff *skb1;
884
885 BUG_ON(sock_owned_by_user(sk));
886
887 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
888 sk->sk_backlog_rcv(sk, skb1);
889 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
890 }
891
892 tp->ucopy.memory = 0;
893 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
894 wake_up_interruptible(sk->sk_sleep);
895 if (!inet_csk_ack_scheduled(sk))
896 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
897 (3 * TCP_RTO_MIN) / 4,
898 TCP_RTO_MAX);
899 }
900 return 1;
901 }
902 return 0;
903 }
904
905
906 #undef STATE_TRACE
907
908 #ifdef STATE_TRACE
909 static const char *statename[]={
910 "Unused","Established","Syn Sent","Syn Recv",
911 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
912 "Close Wait","Last ACK","Listen","Closing"
913 };
914 #endif
915
916 static inline void tcp_set_state(struct sock *sk, int state)
917 {
918 int oldstate = sk->sk_state;
919
920 switch (state) {
921 case TCP_ESTABLISHED:
922 if (oldstate != TCP_ESTABLISHED)
923 TCP_INC_STATS(TCP_MIB_CURRESTAB);
924 break;
925
926 case TCP_CLOSE:
927 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
928 TCP_INC_STATS(TCP_MIB_ESTABRESETS);
929
930 sk->sk_prot->unhash(sk);
931 if (inet_csk(sk)->icsk_bind_hash &&
932 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
933 inet_put_port(&tcp_hashinfo, sk);
934 /* fall through */
935 default:
936 if (oldstate==TCP_ESTABLISHED)
937 TCP_DEC_STATS(TCP_MIB_CURRESTAB);
938 }
939
940 /* Change state AFTER socket is unhashed to avoid closed
941 * socket sitting in hash tables.
942 */
943 sk->sk_state = state;
944
945 #ifdef STATE_TRACE
946 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]);
947 #endif
948 }
949
950 extern void tcp_done(struct sock *sk);
951
952 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
953 {
954 rx_opt->dsack = 0;
955 rx_opt->eff_sacks = 0;
956 rx_opt->num_sacks = 0;
957 }
958
959 /* Determine a window scaling and initial window to offer. */
960 extern void tcp_select_initial_window(int __space, __u32 mss,
961 __u32 *rcv_wnd, __u32 *window_clamp,
962 int wscale_ok, __u8 *rcv_wscale);
963
964 static inline int tcp_win_from_space(int space)
965 {
966 return sysctl_tcp_adv_win_scale<=0 ?
967 (space>>(-sysctl_tcp_adv_win_scale)) :
968 space - (space>>sysctl_tcp_adv_win_scale);
969 }
970
971 /* Note: caller must be prepared to deal with negative returns */
972 static inline int tcp_space(const struct sock *sk)
973 {
974 return tcp_win_from_space(sk->sk_rcvbuf -
975 atomic_read(&sk->sk_rmem_alloc));
976 }
977
978 static inline int tcp_full_space(const struct sock *sk)
979 {
980 return tcp_win_from_space(sk->sk_rcvbuf);
981 }
982
983 static inline void tcp_openreq_init(struct request_sock *req,
984 struct tcp_options_received *rx_opt,
985 struct sk_buff *skb)
986 {
987 struct inet_request_sock *ireq = inet_rsk(req);
988
989 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
990 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
991 req->mss = rx_opt->mss_clamp;
992 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
993 ireq->tstamp_ok = rx_opt->tstamp_ok;
994 ireq->sack_ok = rx_opt->sack_ok;
995 ireq->snd_wscale = rx_opt->snd_wscale;
996 ireq->wscale_ok = rx_opt->wscale_ok;
997 ireq->acked = 0;
998 ireq->ecn_ok = 0;
999 ireq->rmt_port = tcp_hdr(skb)->source;
1000 }
1001
1002 extern void tcp_enter_memory_pressure(void);
1003
1004 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1005 {
1006 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
1007 }
1008
1009 static inline int keepalive_time_when(const struct tcp_sock *tp)
1010 {
1011 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
1012 }
1013
1014 static inline int tcp_fin_time(const struct sock *sk)
1015 {
1016 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1017 const int rto = inet_csk(sk)->icsk_rto;
1018
1019 if (fin_timeout < (rto << 2) - (rto >> 1))
1020 fin_timeout = (rto << 2) - (rto >> 1);
1021
1022 return fin_timeout;
1023 }
1024
1025 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1026 {
1027 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1028 return 0;
1029 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1030 return 0;
1031
1032 /* RST segments are not recommended to carry timestamp,
1033 and, if they do, it is recommended to ignore PAWS because
1034 "their cleanup function should take precedence over timestamps."
1035 Certainly, it is mistake. It is necessary to understand the reasons
1036 of this constraint to relax it: if peer reboots, clock may go
1037 out-of-sync and half-open connections will not be reset.
1038 Actually, the problem would be not existing if all
1039 the implementations followed draft about maintaining clock
1040 via reboots. Linux-2.2 DOES NOT!
1041
1042 However, we can relax time bounds for RST segments to MSL.
1043 */
1044 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1045 return 0;
1046 return 1;
1047 }
1048
1049 #define TCP_CHECK_TIMER(sk) do { } while (0)
1050
1051 static inline void tcp_mib_init(void)
1052 {
1053 /* See RFC 2012 */
1054 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1055 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1056 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1057 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
1058 }
1059
1060 /*from STCP */
1061 static inline void clear_all_retrans_hints(struct tcp_sock *tp){
1062 tp->lost_skb_hint = NULL;
1063 tp->scoreboard_skb_hint = NULL;
1064 tp->retransmit_skb_hint = NULL;
1065 tp->forward_skb_hint = NULL;
1066 tp->fastpath_skb_hint = NULL;
1067 }
1068
1069 /* MD5 Signature */
1070 struct crypto_hash;
1071
1072 /* - key database */
1073 struct tcp_md5sig_key {
1074 u8 *key;
1075 u8 keylen;
1076 };
1077
1078 struct tcp4_md5sig_key {
1079 struct tcp_md5sig_key base;
1080 __be32 addr;
1081 };
1082
1083 struct tcp6_md5sig_key {
1084 struct tcp_md5sig_key base;
1085 #if 0
1086 u32 scope_id; /* XXX */
1087 #endif
1088 struct in6_addr addr;
1089 };
1090
1091 /* - sock block */
1092 struct tcp_md5sig_info {
1093 struct tcp4_md5sig_key *keys4;
1094 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1095 struct tcp6_md5sig_key *keys6;
1096 u32 entries6;
1097 u32 alloced6;
1098 #endif
1099 u32 entries4;
1100 u32 alloced4;
1101 };
1102
1103 /* - pseudo header */
1104 struct tcp4_pseudohdr {
1105 __be32 saddr;
1106 __be32 daddr;
1107 __u8 pad;
1108 __u8 protocol;
1109 __be16 len;
1110 };
1111
1112 struct tcp6_pseudohdr {
1113 struct in6_addr saddr;
1114 struct in6_addr daddr;
1115 __be32 len;
1116 __be32 protocol; /* including padding */
1117 };
1118
1119 union tcp_md5sum_block {
1120 struct tcp4_pseudohdr ip4;
1121 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1122 struct tcp6_pseudohdr ip6;
1123 #endif
1124 };
1125
1126 /* - pool: digest algorithm, hash description and scratch buffer */
1127 struct tcp_md5sig_pool {
1128 struct hash_desc md5_desc;
1129 union tcp_md5sum_block md5_blk;
1130 };
1131
1132 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1133
1134 /* - functions */
1135 extern int tcp_v4_calc_md5_hash(char *md5_hash,
1136 struct tcp_md5sig_key *key,
1137 struct sock *sk,
1138 struct dst_entry *dst,
1139 struct request_sock *req,
1140 struct tcphdr *th,
1141 int protocol, int tcplen);
1142 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1143 struct sock *addr_sk);
1144
1145 extern int tcp_v4_md5_do_add(struct sock *sk,
1146 __be32 addr,
1147 u8 *newkey,
1148 u8 newkeylen);
1149
1150 extern int tcp_v4_md5_do_del(struct sock *sk,
1151 __be32 addr);
1152
1153 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1154 extern void tcp_free_md5sig_pool(void);
1155
1156 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1157 extern void __tcp_put_md5sig_pool(void);
1158
1159 static inline
1160 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1161 {
1162 int cpu = get_cpu();
1163 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1164 if (!ret)
1165 put_cpu();
1166 return ret;
1167 }
1168
1169 static inline void tcp_put_md5sig_pool(void)
1170 {
1171 __tcp_put_md5sig_pool();
1172 put_cpu();
1173 }
1174
1175 /* write queue abstraction */
1176 static inline void tcp_write_queue_purge(struct sock *sk)
1177 {
1178 struct sk_buff *skb;
1179
1180 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1181 sk_stream_free_skb(sk, skb);
1182 sk_stream_mem_reclaim(sk);
1183 }
1184
1185 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1186 {
1187 struct sk_buff *skb = sk->sk_write_queue.next;
1188 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1189 return NULL;
1190 return skb;
1191 }
1192
1193 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1194 {
1195 struct sk_buff *skb = sk->sk_write_queue.prev;
1196 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1197 return NULL;
1198 return skb;
1199 }
1200
1201 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1202 {
1203 return skb->next;
1204 }
1205
1206 #define tcp_for_write_queue(skb, sk) \
1207 for (skb = (sk)->sk_write_queue.next; \
1208 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1209 skb = skb->next)
1210
1211 #define tcp_for_write_queue_from(skb, sk) \
1212 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\
1213 skb = skb->next)
1214
1215 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1216 {
1217 return sk->sk_send_head;
1218 }
1219
1220 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1221 {
1222 struct tcp_sock *tp = tcp_sk(sk);
1223
1224 sk->sk_send_head = skb->next;
1225 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
1226 sk->sk_send_head = NULL;
1227 /* Don't override Nagle indefinately with F-RTO */
1228 if (tp->frto_counter == 2)
1229 tp->frto_counter = 3;
1230 }
1231
1232 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1233 {
1234 if (sk->sk_send_head == skb_unlinked)
1235 sk->sk_send_head = NULL;
1236 }
1237
1238 static inline void tcp_init_send_head(struct sock *sk)
1239 {
1240 sk->sk_send_head = NULL;
1241 }
1242
1243 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1244 {
1245 __skb_queue_tail(&sk->sk_write_queue, skb);
1246 }
1247
1248 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1249 {
1250 __tcp_add_write_queue_tail(sk, skb);
1251
1252 /* Queue it, remembering where we must start sending. */
1253 if (sk->sk_send_head == NULL)
1254 sk->sk_send_head = skb;
1255 }
1256
1257 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1258 {
1259 __skb_queue_head(&sk->sk_write_queue, skb);
1260 }
1261
1262 /* Insert buff after skb on the write queue of sk. */
1263 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1264 struct sk_buff *buff,
1265 struct sock *sk)
1266 {
1267 __skb_append(skb, buff, &sk->sk_write_queue);
1268 }
1269
1270 /* Insert skb between prev and next on the write queue of sk. */
1271 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1272 struct sk_buff *skb,
1273 struct sock *sk)
1274 {
1275 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
1276 }
1277
1278 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1279 {
1280 __skb_unlink(skb, &sk->sk_write_queue);
1281 }
1282
1283 static inline int tcp_skb_is_last(const struct sock *sk,
1284 const struct sk_buff *skb)
1285 {
1286 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1287 }
1288
1289 static inline int tcp_write_queue_empty(struct sock *sk)
1290 {
1291 return skb_queue_empty(&sk->sk_write_queue);
1292 }
1293
1294 /* /proc */
1295 enum tcp_seq_states {
1296 TCP_SEQ_STATE_LISTENING,
1297 TCP_SEQ_STATE_OPENREQ,
1298 TCP_SEQ_STATE_ESTABLISHED,
1299 TCP_SEQ_STATE_TIME_WAIT,
1300 };
1301
1302 struct tcp_seq_afinfo {
1303 struct module *owner;
1304 char *name;
1305 sa_family_t family;
1306 int (*seq_show) (struct seq_file *m, void *v);
1307 struct file_operations *seq_fops;
1308 };
1309
1310 struct tcp_iter_state {
1311 sa_family_t family;
1312 enum tcp_seq_states state;
1313 struct sock *syn_wait_sk;
1314 int bucket, sbucket, num, uid;
1315 struct seq_operations seq_ops;
1316 };
1317
1318 extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo);
1319 extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo);
1320
1321 extern struct request_sock_ops tcp_request_sock_ops;
1322
1323 extern int tcp_v4_destroy_sock(struct sock *sk);
1324
1325 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1326 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1327
1328 #ifdef CONFIG_PROC_FS
1329 extern int tcp4_proc_init(void);
1330 extern void tcp4_proc_exit(void);
1331 #endif
1332
1333 /* TCP af-specific functions */
1334 struct tcp_sock_af_ops {
1335 #ifdef CONFIG_TCP_MD5SIG
1336 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1337 struct sock *addr_sk);
1338 int (*calc_md5_hash) (char *location,
1339 struct tcp_md5sig_key *md5,
1340 struct sock *sk,
1341 struct dst_entry *dst,
1342 struct request_sock *req,
1343 struct tcphdr *th,
1344 int protocol, int len);
1345 int (*md5_add) (struct sock *sk,
1346 struct sock *addr_sk,
1347 u8 *newkey,
1348 u8 len);
1349 int (*md5_parse) (struct sock *sk,
1350 char __user *optval,
1351 int optlen);
1352 #endif
1353 };
1354
1355 struct tcp_request_sock_ops {
1356 #ifdef CONFIG_TCP_MD5SIG
1357 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1358 struct request_sock *req);
1359 #endif
1360 };
1361
1362 extern void tcp_v4_init(struct net_proto_family *ops);
1363 extern void tcp_init(void);
1364
1365 #endif /* _TCP_H */
kernel source for telekom puls (alcatel/mediatek)