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net: change proto destroy method to return void
[mirror_ubuntu-jammy-kernel.git] / include / net / tcp.h
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Definitions for the TCP module.
7 *
8 * Version: @(#)tcp.h 1.0.5 05/23/93
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
17 */
18 #ifndef _TCP_H
19 #define _TCP_H
20
21 #define TCP_DEBUG 1
22 #define FASTRETRANS_DEBUG 1
23
24 #include <linux/list.h>
25 #include <linux/tcp.h>
26 #include <linux/slab.h>
27 #include <linux/cache.h>
28 #include <linux/percpu.h>
29 #include <linux/skbuff.h>
30 #include <linux/dmaengine.h>
31 #include <linux/crypto.h>
32 #include <linux/cryptohash.h>
33
34 #include <net/inet_connection_sock.h>
35 #include <net/inet_timewait_sock.h>
36 #include <net/inet_hashtables.h>
37 #include <net/checksum.h>
38 #include <net/request_sock.h>
39 #include <net/sock.h>
40 #include <net/snmp.h>
41 #include <net/ip.h>
42 #include <net/tcp_states.h>
43 #include <net/inet_ecn.h>
44
45 #include <linux/seq_file.h>
46
47 extern struct inet_hashinfo tcp_hashinfo;
48
49 extern atomic_t tcp_orphan_count;
50 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
51
52 #define MAX_TCP_HEADER (128 + MAX_HEADER)
53
54 /*
55 * Never offer a window over 32767 without using window scaling. Some
56 * poor stacks do signed 16bit maths!
57 */
58 #define MAX_TCP_WINDOW 32767U
59
60 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
61 #define TCP_MIN_MSS 88U
62
63 /* Minimal RCV_MSS. */
64 #define TCP_MIN_RCVMSS 536U
65
66 /* The least MTU to use for probing */
67 #define TCP_BASE_MSS 512
68
69 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
70 #define TCP_FASTRETRANS_THRESH 3
71
72 /* Maximal reordering. */
73 #define TCP_MAX_REORDERING 127
74
75 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
76 #define TCP_MAX_QUICKACKS 16U
77
78 /* urg_data states */
79 #define TCP_URG_VALID 0x0100
80 #define TCP_URG_NOTYET 0x0200
81 #define TCP_URG_READ 0x0400
82
83 #define TCP_RETR1 3 /*
84 * This is how many retries it does before it
85 * tries to figure out if the gateway is
86 * down. Minimal RFC value is 3; it corresponds
87 * to ~3sec-8min depending on RTO.
88 */
89
90 #define TCP_RETR2 15 /*
91 * This should take at least
92 * 90 minutes to time out.
93 * RFC1122 says that the limit is 100 sec.
94 * 15 is ~13-30min depending on RTO.
95 */
96
97 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
98 * connection: ~180sec is RFC minimum */
99
100 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
101 * connection: ~180sec is RFC minimum */
102
103
104 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
105 * socket. 7 is ~50sec-16min.
106 */
107
108
109 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
110 * state, about 60 seconds */
111 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
112 /* BSD style FIN_WAIT2 deadlock breaker.
113 * It used to be 3min, new value is 60sec,
114 * to combine FIN-WAIT-2 timeout with
115 * TIME-WAIT timer.
116 */
117
118 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
119 #if HZ >= 100
120 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
121 #define TCP_ATO_MIN ((unsigned)(HZ/25))
122 #else
123 #define TCP_DELACK_MIN 4U
124 #define TCP_ATO_MIN 4U
125 #endif
126 #define TCP_RTO_MAX ((unsigned)(120*HZ))
127 #define TCP_RTO_MIN ((unsigned)(HZ/5))
128 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
129
130 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
131 * for local resources.
132 */
133
134 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
135 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
136 #define TCP_KEEPALIVE_INTVL (75*HZ)
137
138 #define MAX_TCP_KEEPIDLE 32767
139 #define MAX_TCP_KEEPINTVL 32767
140 #define MAX_TCP_KEEPCNT 127
141 #define MAX_TCP_SYNCNT 127
142
143 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
144
145 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
146 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
147 * after this time. It should be equal
148 * (or greater than) TCP_TIMEWAIT_LEN
149 * to provide reliability equal to one
150 * provided by timewait state.
151 */
152 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
153 * timestamps. It must be less than
154 * minimal timewait lifetime.
155 */
156 /*
157 * TCP option
158 */
159
160 #define TCPOPT_NOP 1 /* Padding */
161 #define TCPOPT_EOL 0 /* End of options */
162 #define TCPOPT_MSS 2 /* Segment size negotiating */
163 #define TCPOPT_WINDOW 3 /* Window scaling */
164 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
165 #define TCPOPT_SACK 5 /* SACK Block */
166 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
167 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
168
169 /*
170 * TCP option lengths
171 */
172
173 #define TCPOLEN_MSS 4
174 #define TCPOLEN_WINDOW 3
175 #define TCPOLEN_SACK_PERM 2
176 #define TCPOLEN_TIMESTAMP 10
177 #define TCPOLEN_MD5SIG 18
178
179 /* But this is what stacks really send out. */
180 #define TCPOLEN_TSTAMP_ALIGNED 12
181 #define TCPOLEN_WSCALE_ALIGNED 4
182 #define TCPOLEN_SACKPERM_ALIGNED 4
183 #define TCPOLEN_SACK_BASE 2
184 #define TCPOLEN_SACK_BASE_ALIGNED 4
185 #define TCPOLEN_SACK_PERBLOCK 8
186 #define TCPOLEN_MD5SIG_ALIGNED 20
187
188 /* Flags in tp->nonagle */
189 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
190 #define TCP_NAGLE_CORK 2 /* Socket is corked */
191 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
192
193 extern struct inet_timewait_death_row tcp_death_row;
194
195 /* sysctl variables for tcp */
196 extern int sysctl_tcp_timestamps;
197 extern int sysctl_tcp_window_scaling;
198 extern int sysctl_tcp_sack;
199 extern int sysctl_tcp_fin_timeout;
200 extern int sysctl_tcp_keepalive_time;
201 extern int sysctl_tcp_keepalive_probes;
202 extern int sysctl_tcp_keepalive_intvl;
203 extern int sysctl_tcp_syn_retries;
204 extern int sysctl_tcp_synack_retries;
205 extern int sysctl_tcp_retries1;
206 extern int sysctl_tcp_retries2;
207 extern int sysctl_tcp_orphan_retries;
208 extern int sysctl_tcp_syncookies;
209 extern int sysctl_tcp_retrans_collapse;
210 extern int sysctl_tcp_stdurg;
211 extern int sysctl_tcp_rfc1337;
212 extern int sysctl_tcp_abort_on_overflow;
213 extern int sysctl_tcp_max_orphans;
214 extern int sysctl_tcp_fack;
215 extern int sysctl_tcp_reordering;
216 extern int sysctl_tcp_ecn;
217 extern int sysctl_tcp_dsack;
218 extern int sysctl_tcp_mem[3];
219 extern int sysctl_tcp_wmem[3];
220 extern int sysctl_tcp_rmem[3];
221 extern int sysctl_tcp_app_win;
222 extern int sysctl_tcp_adv_win_scale;
223 extern int sysctl_tcp_tw_reuse;
224 extern int sysctl_tcp_frto;
225 extern int sysctl_tcp_frto_response;
226 extern int sysctl_tcp_low_latency;
227 extern int sysctl_tcp_dma_copybreak;
228 extern int sysctl_tcp_nometrics_save;
229 extern int sysctl_tcp_moderate_rcvbuf;
230 extern int sysctl_tcp_tso_win_divisor;
231 extern int sysctl_tcp_abc;
232 extern int sysctl_tcp_mtu_probing;
233 extern int sysctl_tcp_base_mss;
234 extern int sysctl_tcp_workaround_signed_windows;
235 extern int sysctl_tcp_slow_start_after_idle;
236 extern int sysctl_tcp_max_ssthresh;
237
238 extern atomic_t tcp_memory_allocated;
239 extern atomic_t tcp_sockets_allocated;
240 extern int tcp_memory_pressure;
241
242 /*
243 * The next routines deal with comparing 32 bit unsigned ints
244 * and worry about wraparound (automatic with unsigned arithmetic).
245 */
246
247 static inline int before(__u32 seq1, __u32 seq2)
248 {
249 return (__s32)(seq1-seq2) < 0;
250 }
251 #define after(seq2, seq1) before(seq1, seq2)
252
253 /* is s2<=s1<=s3 ? */
254 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
255 {
256 return seq3 - seq2 >= seq1 - seq2;
257 }
258
259 static inline int tcp_too_many_orphans(struct sock *sk, int num)
260 {
261 return (num > sysctl_tcp_max_orphans) ||
262 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
263 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
264 }
265
266 extern struct proto tcp_prot;
267
268 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
269 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
270 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
271 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
272 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
273 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
274 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
275
276 extern void tcp_v4_err(struct sk_buff *skb, u32);
277
278 extern void tcp_shutdown (struct sock *sk, int how);
279
280 extern int tcp_v4_rcv(struct sk_buff *skb);
281
282 extern int tcp_v4_remember_stamp(struct sock *sk);
283
284 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
285
286 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
287 struct msghdr *msg, size_t size);
288 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
289
290 extern int tcp_ioctl(struct sock *sk,
291 int cmd,
292 unsigned long arg);
293
294 extern int tcp_rcv_state_process(struct sock *sk,
295 struct sk_buff *skb,
296 struct tcphdr *th,
297 unsigned len);
298
299 extern int tcp_rcv_established(struct sock *sk,
300 struct sk_buff *skb,
301 struct tcphdr *th,
302 unsigned len);
303
304 extern void tcp_rcv_space_adjust(struct sock *sk);
305
306 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
307
308 extern int tcp_twsk_unique(struct sock *sk,
309 struct sock *sktw, void *twp);
310
311 extern void tcp_twsk_destructor(struct sock *sk);
312
313 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
314 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
315
316 static inline void tcp_dec_quickack_mode(struct sock *sk,
317 const unsigned int pkts)
318 {
319 struct inet_connection_sock *icsk = inet_csk(sk);
320
321 if (icsk->icsk_ack.quick) {
322 if (pkts >= icsk->icsk_ack.quick) {
323 icsk->icsk_ack.quick = 0;
324 /* Leaving quickack mode we deflate ATO. */
325 icsk->icsk_ack.ato = TCP_ATO_MIN;
326 } else
327 icsk->icsk_ack.quick -= pkts;
328 }
329 }
330
331 extern void tcp_enter_quickack_mode(struct sock *sk);
332
333 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
334 {
335 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
336 }
337
338 #define TCP_ECN_OK 1
339 #define TCP_ECN_QUEUE_CWR 2
340 #define TCP_ECN_DEMAND_CWR 4
341
342 static __inline__ void
343 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
344 {
345 if (sysctl_tcp_ecn && th->ece && th->cwr)
346 inet_rsk(req)->ecn_ok = 1;
347 }
348
349 enum tcp_tw_status
350 {
351 TCP_TW_SUCCESS = 0,
352 TCP_TW_RST = 1,
353 TCP_TW_ACK = 2,
354 TCP_TW_SYN = 3
355 };
356
357
358 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
359 struct sk_buff *skb,
360 const struct tcphdr *th);
361
362 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
363 struct request_sock *req,
364 struct request_sock **prev);
365 extern int tcp_child_process(struct sock *parent,
366 struct sock *child,
367 struct sk_buff *skb);
368 extern int tcp_use_frto(struct sock *sk);
369 extern void tcp_enter_frto(struct sock *sk);
370 extern void tcp_enter_loss(struct sock *sk, int how);
371 extern void tcp_clear_retrans(struct tcp_sock *tp);
372 extern void tcp_update_metrics(struct sock *sk);
373
374 extern void tcp_close(struct sock *sk,
375 long timeout);
376 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
377
378 extern int tcp_getsockopt(struct sock *sk, int level,
379 int optname,
380 char __user *optval,
381 int __user *optlen);
382 extern int tcp_setsockopt(struct sock *sk, int level,
383 int optname, char __user *optval,
384 int optlen);
385 extern int compat_tcp_getsockopt(struct sock *sk,
386 int level, int optname,
387 char __user *optval, int __user *optlen);
388 extern int compat_tcp_setsockopt(struct sock *sk,
389 int level, int optname,
390 char __user *optval, int optlen);
391 extern void tcp_set_keepalive(struct sock *sk, int val);
392 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
393 struct msghdr *msg,
394 size_t len, int nonblock,
395 int flags, int *addr_len);
396
397 extern void tcp_parse_options(struct sk_buff *skb,
398 struct tcp_options_received *opt_rx,
399 int estab);
400
401 extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
402
403 /*
404 * TCP v4 functions exported for the inet6 API
405 */
406
407 extern void tcp_v4_send_check(struct sock *sk, int len,
408 struct sk_buff *skb);
409
410 extern int tcp_v4_conn_request(struct sock *sk,
411 struct sk_buff *skb);
412
413 extern struct sock * tcp_create_openreq_child(struct sock *sk,
414 struct request_sock *req,
415 struct sk_buff *skb);
416
417 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
418 struct sk_buff *skb,
419 struct request_sock *req,
420 struct dst_entry *dst);
421
422 extern int tcp_v4_do_rcv(struct sock *sk,
423 struct sk_buff *skb);
424
425 extern int tcp_v4_connect(struct sock *sk,
426 struct sockaddr *uaddr,
427 int addr_len);
428
429 extern int tcp_connect(struct sock *sk);
430
431 extern struct sk_buff * tcp_make_synack(struct sock *sk,
432 struct dst_entry *dst,
433 struct request_sock *req);
434
435 extern int tcp_disconnect(struct sock *sk, int flags);
436
437
438 /* From syncookies.c */
439 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
440 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
441 struct ip_options *opt);
442 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
443 __u16 *mss);
444
445 extern __u32 cookie_init_timestamp(struct request_sock *req);
446 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
447
448 /* From net/ipv6/syncookies.c */
449 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
450 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
451 __u16 *mss);
452
453 /* tcp_output.c */
454
455 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
456 int nonagle);
457 extern int tcp_may_send_now(struct sock *sk);
458 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
459 extern void tcp_xmit_retransmit_queue(struct sock *);
460 extern void tcp_simple_retransmit(struct sock *);
461 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
462 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
463
464 extern void tcp_send_probe0(struct sock *);
465 extern void tcp_send_partial(struct sock *);
466 extern int tcp_write_wakeup(struct sock *);
467 extern void tcp_send_fin(struct sock *sk);
468 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
469 extern int tcp_send_synack(struct sock *);
470 extern void tcp_push_one(struct sock *, unsigned int mss_now);
471 extern void tcp_send_ack(struct sock *sk);
472 extern void tcp_send_delayed_ack(struct sock *sk);
473
474 /* tcp_input.c */
475 extern void tcp_cwnd_application_limited(struct sock *sk);
476
477 /* tcp_timer.c */
478 extern void tcp_init_xmit_timers(struct sock *);
479 static inline void tcp_clear_xmit_timers(struct sock *sk)
480 {
481 inet_csk_clear_xmit_timers(sk);
482 }
483
484 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
485 extern unsigned int tcp_current_mss(struct sock *sk, int large);
486
487 /* tcp.c */
488 extern void tcp_get_info(struct sock *, struct tcp_info *);
489
490 /* Read 'sendfile()'-style from a TCP socket */
491 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
492 unsigned int, size_t);
493 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
494 sk_read_actor_t recv_actor);
495
496 extern void tcp_initialize_rcv_mss(struct sock *sk);
497
498 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
499 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
500 extern void tcp_mtup_init(struct sock *sk);
501
502 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
503 {
504 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
505 ntohl(TCP_FLAG_ACK) |
506 snd_wnd);
507 }
508
509 static inline void tcp_fast_path_on(struct tcp_sock *tp)
510 {
511 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
512 }
513
514 static inline void tcp_fast_path_check(struct sock *sk)
515 {
516 struct tcp_sock *tp = tcp_sk(sk);
517
518 if (skb_queue_empty(&tp->out_of_order_queue) &&
519 tp->rcv_wnd &&
520 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
521 !tp->urg_data)
522 tcp_fast_path_on(tp);
523 }
524
525 /* Compute the actual receive window we are currently advertising.
526 * Rcv_nxt can be after the window if our peer push more data
527 * than the offered window.
528 */
529 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
530 {
531 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
532
533 if (win < 0)
534 win = 0;
535 return (u32) win;
536 }
537
538 /* Choose a new window, without checks for shrinking, and without
539 * scaling applied to the result. The caller does these things
540 * if necessary. This is a "raw" window selection.
541 */
542 extern u32 __tcp_select_window(struct sock *sk);
543
544 /* TCP timestamps are only 32-bits, this causes a slight
545 * complication on 64-bit systems since we store a snapshot
546 * of jiffies in the buffer control blocks below. We decided
547 * to use only the low 32-bits of jiffies and hide the ugly
548 * casts with the following macro.
549 */
550 #define tcp_time_stamp ((__u32)(jiffies))
551
552 /* This is what the send packet queuing engine uses to pass
553 * TCP per-packet control information to the transmission
554 * code. We also store the host-order sequence numbers in
555 * here too. This is 36 bytes on 32-bit architectures,
556 * 40 bytes on 64-bit machines, if this grows please adjust
557 * skbuff.h:skbuff->cb[xxx] size appropriately.
558 */
559 struct tcp_skb_cb {
560 union {
561 struct inet_skb_parm h4;
562 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
563 struct inet6_skb_parm h6;
564 #endif
565 } header; /* For incoming frames */
566 __u32 seq; /* Starting sequence number */
567 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
568 __u32 when; /* used to compute rtt's */
569 __u8 flags; /* TCP header flags. */
570
571 /* NOTE: These must match up to the flags byte in a
572 * real TCP header.
573 */
574 #define TCPCB_FLAG_FIN 0x01
575 #define TCPCB_FLAG_SYN 0x02
576 #define TCPCB_FLAG_RST 0x04
577 #define TCPCB_FLAG_PSH 0x08
578 #define TCPCB_FLAG_ACK 0x10
579 #define TCPCB_FLAG_URG 0x20
580 #define TCPCB_FLAG_ECE 0x40
581 #define TCPCB_FLAG_CWR 0x80
582
583 __u8 sacked; /* State flags for SACK/FACK. */
584 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
585 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
586 #define TCPCB_LOST 0x04 /* SKB is lost */
587 #define TCPCB_TAGBITS 0x07 /* All tag bits */
588
589 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
590 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
591
592 __u16 urg_ptr; /* Valid w/URG flags is set. */
593 __u32 ack_seq; /* Sequence number ACK'd */
594 };
595
596 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
597
598 /* Due to TSO, an SKB can be composed of multiple actual
599 * packets. To keep these tracked properly, we use this.
600 */
601 static inline int tcp_skb_pcount(const struct sk_buff *skb)
602 {
603 return skb_shinfo(skb)->gso_segs;
604 }
605
606 /* This is valid iff tcp_skb_pcount() > 1. */
607 static inline int tcp_skb_mss(const struct sk_buff *skb)
608 {
609 return skb_shinfo(skb)->gso_size;
610 }
611
612 static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
613 {
614 if (*count) {
615 *count -= decr;
616 if ((int)*count < 0)
617 *count = 0;
618 }
619 }
620
621 static inline void tcp_dec_pcount_approx(__u32 *count,
622 const struct sk_buff *skb)
623 {
624 tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
625 }
626
627 /* Events passed to congestion control interface */
628 enum tcp_ca_event {
629 CA_EVENT_TX_START, /* first transmit when no packets in flight */
630 CA_EVENT_CWND_RESTART, /* congestion window restart */
631 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
632 CA_EVENT_FRTO, /* fast recovery timeout */
633 CA_EVENT_LOSS, /* loss timeout */
634 CA_EVENT_FAST_ACK, /* in sequence ack */
635 CA_EVENT_SLOW_ACK, /* other ack */
636 };
637
638 /*
639 * Interface for adding new TCP congestion control handlers
640 */
641 #define TCP_CA_NAME_MAX 16
642 #define TCP_CA_MAX 128
643 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
644
645 #define TCP_CONG_NON_RESTRICTED 0x1
646 #define TCP_CONG_RTT_STAMP 0x2
647
648 struct tcp_congestion_ops {
649 struct list_head list;
650 unsigned long flags;
651
652 /* initialize private data (optional) */
653 void (*init)(struct sock *sk);
654 /* cleanup private data (optional) */
655 void (*release)(struct sock *sk);
656
657 /* return slow start threshold (required) */
658 u32 (*ssthresh)(struct sock *sk);
659 /* lower bound for congestion window (optional) */
660 u32 (*min_cwnd)(const struct sock *sk);
661 /* do new cwnd calculation (required) */
662 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
663 /* call before changing ca_state (optional) */
664 void (*set_state)(struct sock *sk, u8 new_state);
665 /* call when cwnd event occurs (optional) */
666 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
667 /* new value of cwnd after loss (optional) */
668 u32 (*undo_cwnd)(struct sock *sk);
669 /* hook for packet ack accounting (optional) */
670 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
671 /* get info for inet_diag (optional) */
672 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
673
674 char name[TCP_CA_NAME_MAX];
675 struct module *owner;
676 };
677
678 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
679 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
680
681 extern void tcp_init_congestion_control(struct sock *sk);
682 extern void tcp_cleanup_congestion_control(struct sock *sk);
683 extern int tcp_set_default_congestion_control(const char *name);
684 extern void tcp_get_default_congestion_control(char *name);
685 extern void tcp_get_available_congestion_control(char *buf, size_t len);
686 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
687 extern int tcp_set_allowed_congestion_control(char *allowed);
688 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
689 extern void tcp_slow_start(struct tcp_sock *tp);
690
691 extern struct tcp_congestion_ops tcp_init_congestion_ops;
692 extern u32 tcp_reno_ssthresh(struct sock *sk);
693 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
694 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
695 extern struct tcp_congestion_ops tcp_reno;
696
697 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
698 {
699 struct inet_connection_sock *icsk = inet_csk(sk);
700
701 if (icsk->icsk_ca_ops->set_state)
702 icsk->icsk_ca_ops->set_state(sk, ca_state);
703 icsk->icsk_ca_state = ca_state;
704 }
705
706 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
707 {
708 const struct inet_connection_sock *icsk = inet_csk(sk);
709
710 if (icsk->icsk_ca_ops->cwnd_event)
711 icsk->icsk_ca_ops->cwnd_event(sk, event);
712 }
713
714 /* These functions determine how the current flow behaves in respect of SACK
715 * handling. SACK is negotiated with the peer, and therefore it can vary
716 * between different flows.
717 *
718 * tcp_is_sack - SACK enabled
719 * tcp_is_reno - No SACK
720 * tcp_is_fack - FACK enabled, implies SACK enabled
721 */
722 static inline int tcp_is_sack(const struct tcp_sock *tp)
723 {
724 return tp->rx_opt.sack_ok;
725 }
726
727 static inline int tcp_is_reno(const struct tcp_sock *tp)
728 {
729 return !tcp_is_sack(tp);
730 }
731
732 static inline int tcp_is_fack(const struct tcp_sock *tp)
733 {
734 return tp->rx_opt.sack_ok & 2;
735 }
736
737 static inline void tcp_enable_fack(struct tcp_sock *tp)
738 {
739 tp->rx_opt.sack_ok |= 2;
740 }
741
742 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
743 {
744 return tp->sacked_out + tp->lost_out;
745 }
746
747 /* This determines how many packets are "in the network" to the best
748 * of our knowledge. In many cases it is conservative, but where
749 * detailed information is available from the receiver (via SACK
750 * blocks etc.) we can make more aggressive calculations.
751 *
752 * Use this for decisions involving congestion control, use just
753 * tp->packets_out to determine if the send queue is empty or not.
754 *
755 * Read this equation as:
756 *
757 * "Packets sent once on transmission queue" MINUS
758 * "Packets left network, but not honestly ACKed yet" PLUS
759 * "Packets fast retransmitted"
760 */
761 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
762 {
763 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
764 }
765
766 extern int tcp_limit_reno_sacked(struct tcp_sock *tp);
767
768 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
769 * The exception is rate halving phase, when cwnd is decreasing towards
770 * ssthresh.
771 */
772 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
773 {
774 const struct tcp_sock *tp = tcp_sk(sk);
775 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
776 return tp->snd_ssthresh;
777 else
778 return max(tp->snd_ssthresh,
779 ((tp->snd_cwnd >> 1) +
780 (tp->snd_cwnd >> 2)));
781 }
782
783 /* Use define here intentionally to get WARN_ON location shown at the caller */
784 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
785
786 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
787 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
788
789 /* Slow start with delack produces 3 packets of burst, so that
790 * it is safe "de facto". This will be the default - same as
791 * the default reordering threshold - but if reordering increases,
792 * we must be able to allow cwnd to burst at least this much in order
793 * to not pull it back when holes are filled.
794 */
795 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
796 {
797 return tp->reordering;
798 }
799
800 /* Returns end sequence number of the receiver's advertised window */
801 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
802 {
803 return tp->snd_una + tp->snd_wnd;
804 }
805 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
806
807 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
808 const struct sk_buff *skb)
809 {
810 if (skb->len < mss)
811 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
812 }
813
814 static inline void tcp_check_probe_timer(struct sock *sk)
815 {
816 struct tcp_sock *tp = tcp_sk(sk);
817 const struct inet_connection_sock *icsk = inet_csk(sk);
818
819 if (!tp->packets_out && !icsk->icsk_pending)
820 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
821 icsk->icsk_rto, TCP_RTO_MAX);
822 }
823
824 static inline void tcp_push_pending_frames(struct sock *sk)
825 {
826 struct tcp_sock *tp = tcp_sk(sk);
827
828 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
829 }
830
831 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
832 {
833 tp->snd_wl1 = seq;
834 }
835
836 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
837 {
838 tp->snd_wl1 = seq;
839 }
840
841 /*
842 * Calculate(/check) TCP checksum
843 */
844 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
845 __be32 daddr, __wsum base)
846 {
847 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
848 }
849
850 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
851 {
852 return __skb_checksum_complete(skb);
853 }
854
855 static inline int tcp_checksum_complete(struct sk_buff *skb)
856 {
857 return !skb_csum_unnecessary(skb) &&
858 __tcp_checksum_complete(skb);
859 }
860
861 /* Prequeue for VJ style copy to user, combined with checksumming. */
862
863 static inline void tcp_prequeue_init(struct tcp_sock *tp)
864 {
865 tp->ucopy.task = NULL;
866 tp->ucopy.len = 0;
867 tp->ucopy.memory = 0;
868 skb_queue_head_init(&tp->ucopy.prequeue);
869 #ifdef CONFIG_NET_DMA
870 tp->ucopy.dma_chan = NULL;
871 tp->ucopy.wakeup = 0;
872 tp->ucopy.pinned_list = NULL;
873 tp->ucopy.dma_cookie = 0;
874 #endif
875 }
876
877 /* Packet is added to VJ-style prequeue for processing in process
878 * context, if a reader task is waiting. Apparently, this exciting
879 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
880 * failed somewhere. Latency? Burstiness? Well, at least now we will
881 * see, why it failed. 8)8) --ANK
882 *
883 * NOTE: is this not too big to inline?
884 */
885 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
886 {
887 struct tcp_sock *tp = tcp_sk(sk);
888
889 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
890 __skb_queue_tail(&tp->ucopy.prequeue, skb);
891 tp->ucopy.memory += skb->truesize;
892 if (tp->ucopy.memory > sk->sk_rcvbuf) {
893 struct sk_buff *skb1;
894
895 BUG_ON(sock_owned_by_user(sk));
896
897 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
898 sk->sk_backlog_rcv(sk, skb1);
899 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
900 }
901
902 tp->ucopy.memory = 0;
903 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
904 wake_up_interruptible(sk->sk_sleep);
905 if (!inet_csk_ack_scheduled(sk))
906 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
907 (3 * TCP_RTO_MIN) / 4,
908 TCP_RTO_MAX);
909 }
910 return 1;
911 }
912 return 0;
913 }
914
915
916 #undef STATE_TRACE
917
918 #ifdef STATE_TRACE
919 static const char *statename[]={
920 "Unused","Established","Syn Sent","Syn Recv",
921 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
922 "Close Wait","Last ACK","Listen","Closing"
923 };
924 #endif
925 extern void tcp_set_state(struct sock *sk, int state);
926
927 extern void tcp_done(struct sock *sk);
928
929 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
930 {
931 rx_opt->dsack = 0;
932 rx_opt->eff_sacks = 0;
933 rx_opt->num_sacks = 0;
934 }
935
936 /* Determine a window scaling and initial window to offer. */
937 extern void tcp_select_initial_window(int __space, __u32 mss,
938 __u32 *rcv_wnd, __u32 *window_clamp,
939 int wscale_ok, __u8 *rcv_wscale);
940
941 static inline int tcp_win_from_space(int space)
942 {
943 return sysctl_tcp_adv_win_scale<=0 ?
944 (space>>(-sysctl_tcp_adv_win_scale)) :
945 space - (space>>sysctl_tcp_adv_win_scale);
946 }
947
948 /* Note: caller must be prepared to deal with negative returns */
949 static inline int tcp_space(const struct sock *sk)
950 {
951 return tcp_win_from_space(sk->sk_rcvbuf -
952 atomic_read(&sk->sk_rmem_alloc));
953 }
954
955 static inline int tcp_full_space(const struct sock *sk)
956 {
957 return tcp_win_from_space(sk->sk_rcvbuf);
958 }
959
960 static inline void tcp_openreq_init(struct request_sock *req,
961 struct tcp_options_received *rx_opt,
962 struct sk_buff *skb)
963 {
964 struct inet_request_sock *ireq = inet_rsk(req);
965
966 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
967 req->cookie_ts = 0;
968 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
969 req->mss = rx_opt->mss_clamp;
970 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
971 ireq->tstamp_ok = rx_opt->tstamp_ok;
972 ireq->sack_ok = rx_opt->sack_ok;
973 ireq->snd_wscale = rx_opt->snd_wscale;
974 ireq->wscale_ok = rx_opt->wscale_ok;
975 ireq->acked = 0;
976 ireq->ecn_ok = 0;
977 ireq->rmt_port = tcp_hdr(skb)->source;
978 }
979
980 extern void tcp_enter_memory_pressure(void);
981
982 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
983 {
984 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
985 }
986
987 static inline int keepalive_time_when(const struct tcp_sock *tp)
988 {
989 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
990 }
991
992 static inline int tcp_fin_time(const struct sock *sk)
993 {
994 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
995 const int rto = inet_csk(sk)->icsk_rto;
996
997 if (fin_timeout < (rto << 2) - (rto >> 1))
998 fin_timeout = (rto << 2) - (rto >> 1);
999
1000 return fin_timeout;
1001 }
1002
1003 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1004 {
1005 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1006 return 0;
1007 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1008 return 0;
1009
1010 /* RST segments are not recommended to carry timestamp,
1011 and, if they do, it is recommended to ignore PAWS because
1012 "their cleanup function should take precedence over timestamps."
1013 Certainly, it is mistake. It is necessary to understand the reasons
1014 of this constraint to relax it: if peer reboots, clock may go
1015 out-of-sync and half-open connections will not be reset.
1016 Actually, the problem would be not existing if all
1017 the implementations followed draft about maintaining clock
1018 via reboots. Linux-2.2 DOES NOT!
1019
1020 However, we can relax time bounds for RST segments to MSL.
1021 */
1022 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1023 return 0;
1024 return 1;
1025 }
1026
1027 #define TCP_CHECK_TIMER(sk) do { } while (0)
1028
1029 static inline void tcp_mib_init(void)
1030 {
1031 /* See RFC 2012 */
1032 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1033 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1034 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1035 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
1036 }
1037
1038 /* from STCP */
1039 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1040 {
1041 tp->lost_skb_hint = NULL;
1042 tp->scoreboard_skb_hint = NULL;
1043 tp->retransmit_skb_hint = NULL;
1044 tp->forward_skb_hint = NULL;
1045 }
1046
1047 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1048 {
1049 tcp_clear_retrans_hints_partial(tp);
1050 }
1051
1052 /* MD5 Signature */
1053 struct crypto_hash;
1054
1055 /* - key database */
1056 struct tcp_md5sig_key {
1057 u8 *key;
1058 u8 keylen;
1059 };
1060
1061 struct tcp4_md5sig_key {
1062 struct tcp_md5sig_key base;
1063 __be32 addr;
1064 };
1065
1066 struct tcp6_md5sig_key {
1067 struct tcp_md5sig_key base;
1068 #if 0
1069 u32 scope_id; /* XXX */
1070 #endif
1071 struct in6_addr addr;
1072 };
1073
1074 /* - sock block */
1075 struct tcp_md5sig_info {
1076 struct tcp4_md5sig_key *keys4;
1077 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1078 struct tcp6_md5sig_key *keys6;
1079 u32 entries6;
1080 u32 alloced6;
1081 #endif
1082 u32 entries4;
1083 u32 alloced4;
1084 };
1085
1086 /* - pseudo header */
1087 struct tcp4_pseudohdr {
1088 __be32 saddr;
1089 __be32 daddr;
1090 __u8 pad;
1091 __u8 protocol;
1092 __be16 len;
1093 };
1094
1095 struct tcp6_pseudohdr {
1096 struct in6_addr saddr;
1097 struct in6_addr daddr;
1098 __be32 len;
1099 __be32 protocol; /* including padding */
1100 };
1101
1102 union tcp_md5sum_block {
1103 struct tcp4_pseudohdr ip4;
1104 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1105 struct tcp6_pseudohdr ip6;
1106 #endif
1107 };
1108
1109 /* - pool: digest algorithm, hash description and scratch buffer */
1110 struct tcp_md5sig_pool {
1111 struct hash_desc md5_desc;
1112 union tcp_md5sum_block md5_blk;
1113 };
1114
1115 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1116
1117 /* - functions */
1118 extern int tcp_calc_md5_hash(char *md5_hash,
1119 struct tcp_md5sig_key *key,
1120 int bplen,
1121 struct tcphdr *th,
1122 unsigned int tcplen,
1123 struct tcp_md5sig_pool *hp);
1124
1125 extern int tcp_v4_calc_md5_hash(char *md5_hash,
1126 struct tcp_md5sig_key *key,
1127 struct sock *sk,
1128 struct dst_entry *dst,
1129 struct request_sock *req,
1130 struct tcphdr *th,
1131 unsigned int tcplen);
1132 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1133 struct sock *addr_sk);
1134
1135 extern int tcp_v4_md5_do_add(struct sock *sk,
1136 __be32 addr,
1137 u8 *newkey,
1138 u8 newkeylen);
1139
1140 extern int tcp_v4_md5_do_del(struct sock *sk,
1141 __be32 addr);
1142
1143 #ifdef CONFIG_TCP_MD5SIG
1144 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1145 &(struct tcp_md5sig_key) { \
1146 .key = (twsk)->tw_md5_key, \
1147 .keylen = (twsk)->tw_md5_keylen, \
1148 } : NULL)
1149 #else
1150 #define tcp_twsk_md5_key(twsk) NULL
1151 #endif
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_wmem_free_skb(sk, skb);
1182 sk_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 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1216 for (tmp = skb->next; \
1217 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1218 skb = tmp, tmp = skb->next)
1219
1220 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1221 {
1222 return sk->sk_send_head;
1223 }
1224
1225 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1226 {
1227 sk->sk_send_head = skb->next;
1228 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
1229 sk->sk_send_head = NULL;
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 if (tcp_sk(sk)->highest_sack == NULL)
1257 tcp_sk(sk)->highest_sack = skb;
1258 }
1259 }
1260
1261 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1262 {
1263 __skb_queue_head(&sk->sk_write_queue, skb);
1264 }
1265
1266 /* Insert buff after skb on the write queue of sk. */
1267 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1268 struct sk_buff *buff,
1269 struct sock *sk)
1270 {
1271 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1272 }
1273
1274 /* Insert skb between prev and next on the write queue of sk. */
1275 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1276 struct sk_buff *skb,
1277 struct sock *sk)
1278 {
1279 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
1280
1281 if (sk->sk_send_head == skb)
1282 sk->sk_send_head = new;
1283 }
1284
1285 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1286 {
1287 __skb_unlink(skb, &sk->sk_write_queue);
1288 }
1289
1290 static inline int tcp_skb_is_last(const struct sock *sk,
1291 const struct sk_buff *skb)
1292 {
1293 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1294 }
1295
1296 static inline int tcp_write_queue_empty(struct sock *sk)
1297 {
1298 return skb_queue_empty(&sk->sk_write_queue);
1299 }
1300
1301 /* Start sequence of the highest skb with SACKed bit, valid only if
1302 * sacked > 0 or when the caller has ensured validity by itself.
1303 */
1304 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1305 {
1306 if (!tp->sacked_out)
1307 return tp->snd_una;
1308
1309 if (tp->highest_sack == NULL)
1310 return tp->snd_nxt;
1311
1312 return TCP_SKB_CB(tp->highest_sack)->seq;
1313 }
1314
1315 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1316 {
1317 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1318 tcp_write_queue_next(sk, skb);
1319 }
1320
1321 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1322 {
1323 return tcp_sk(sk)->highest_sack;
1324 }
1325
1326 static inline void tcp_highest_sack_reset(struct sock *sk)
1327 {
1328 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1329 }
1330
1331 /* Called when old skb is about to be deleted (to be combined with new skb) */
1332 static inline void tcp_highest_sack_combine(struct sock *sk,
1333 struct sk_buff *old,
1334 struct sk_buff *new)
1335 {
1336 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1337 tcp_sk(sk)->highest_sack = new;
1338 }
1339
1340 /* /proc */
1341 enum tcp_seq_states {
1342 TCP_SEQ_STATE_LISTENING,
1343 TCP_SEQ_STATE_OPENREQ,
1344 TCP_SEQ_STATE_ESTABLISHED,
1345 TCP_SEQ_STATE_TIME_WAIT,
1346 };
1347
1348 struct tcp_seq_afinfo {
1349 char *name;
1350 sa_family_t family;
1351 struct file_operations seq_fops;
1352 struct seq_operations seq_ops;
1353 };
1354
1355 struct tcp_iter_state {
1356 struct seq_net_private p;
1357 sa_family_t family;
1358 enum tcp_seq_states state;
1359 struct sock *syn_wait_sk;
1360 int bucket, sbucket, num, uid;
1361 };
1362
1363 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1364 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1365
1366 extern struct request_sock_ops tcp_request_sock_ops;
1367 extern struct request_sock_ops tcp6_request_sock_ops;
1368
1369 extern void tcp_v4_destroy_sock(struct sock *sk);
1370
1371 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1372 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1373
1374 #ifdef CONFIG_PROC_FS
1375 extern int tcp4_proc_init(void);
1376 extern void tcp4_proc_exit(void);
1377 #endif
1378
1379 /* TCP af-specific functions */
1380 struct tcp_sock_af_ops {
1381 #ifdef CONFIG_TCP_MD5SIG
1382 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1383 struct sock *addr_sk);
1384 int (*calc_md5_hash) (char *location,
1385 struct tcp_md5sig_key *md5,
1386 struct sock *sk,
1387 struct dst_entry *dst,
1388 struct request_sock *req,
1389 struct tcphdr *th,
1390 unsigned int len);
1391 int (*md5_add) (struct sock *sk,
1392 struct sock *addr_sk,
1393 u8 *newkey,
1394 u8 len);
1395 int (*md5_parse) (struct sock *sk,
1396 char __user *optval,
1397 int optlen);
1398 #endif
1399 };
1400
1401 struct tcp_request_sock_ops {
1402 #ifdef CONFIG_TCP_MD5SIG
1403 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1404 struct request_sock *req);
1405 #endif
1406 };
1407
1408 extern void tcp_v4_init(void);
1409 extern void tcp_init(void);
1410
1411 #endif /* _TCP_H */
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