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fed up with those stupid warnings
[mmotm.git] / include / net / tcp.h
blob03a49c7033774c9769921e69cd233d55882ad667
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 #include <net/dst.h>
45
46 #include <linux/seq_file.h>
47
48 extern struct inet_hashinfo tcp_hashinfo;
49
50 extern struct percpu_counter tcp_orphan_count;
51 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
52
53 #define MAX_TCP_HEADER (128 + MAX_HEADER)
54 #define MAX_TCP_OPTION_SPACE 40
55
56 /*
57 * Never offer a window over 32767 without using window scaling. Some
58 * poor stacks do signed 16bit maths!
59 */
60 #define MAX_TCP_WINDOW 32767U
61
62 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
63 #define TCP_MIN_MSS 88U
64
65 /* Minimal RCV_MSS. */
66 #define TCP_MIN_RCVMSS 536U
67
68 /* The least MTU to use for probing */
69 #define TCP_BASE_MSS 512
70
71 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
72 #define TCP_FASTRETRANS_THRESH 3
73
74 /* Maximal reordering. */
75 #define TCP_MAX_REORDERING 127
76
77 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
78 #define TCP_MAX_QUICKACKS 16U
79
80 /* urg_data states */
81 #define TCP_URG_VALID 0x0100
82 #define TCP_URG_NOTYET 0x0200
83 #define TCP_URG_READ 0x0400
84
85 #define TCP_RETR1 3 /*
86 * This is how many retries it does before it
87 * tries to figure out if the gateway is
88 * down. Minimal RFC value is 3; it corresponds
89 * to ~3sec-8min depending on RTO.
90 */
91
92 #define TCP_RETR2 15 /*
93 * This should take at least
94 * 90 minutes to time out.
95 * RFC1122 says that the limit is 100 sec.
96 * 15 is ~13-30min depending on RTO.
97 */
98
99 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
100 * connection: ~180sec is RFC minimum */
101
102 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
103 * connection: ~180sec is RFC minimum */
104
105
106 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
107 * socket. 7 is ~50sec-16min.
108 */
109
110
111 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
112 * state, about 60 seconds */
113 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
114 /* BSD style FIN_WAIT2 deadlock breaker.
115 * It used to be 3min, new value is 60sec,
116 * to combine FIN-WAIT-2 timeout with
117 * TIME-WAIT timer.
118 */
119
120 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
121 #if HZ >= 100
122 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
123 #define TCP_ATO_MIN ((unsigned)(HZ/25))
124 #else
125 #define TCP_DELACK_MIN 4U
126 #define TCP_ATO_MIN 4U
127 #endif
128 #define TCP_RTO_MAX ((unsigned)(120*HZ))
129 #define TCP_RTO_MIN ((unsigned)(HZ/5))
130 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
131
132 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
133 * for local resources.
134 */
135
136 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
137 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
138 #define TCP_KEEPALIVE_INTVL (75*HZ)
139
140 #define MAX_TCP_KEEPIDLE 32767
141 #define MAX_TCP_KEEPINTVL 32767
142 #define MAX_TCP_KEEPCNT 127
143 #define MAX_TCP_SYNCNT 127
144
145 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
146
147 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
148 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
149 * after this time. It should be equal
150 * (or greater than) TCP_TIMEWAIT_LEN
151 * to provide reliability equal to one
152 * provided by timewait state.
153 */
154 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
155 * timestamps. It must be less than
156 * minimal timewait lifetime.
157 */
158 /*
159 * TCP option
160 */
161
162 #define TCPOPT_NOP 1 /* Padding */
163 #define TCPOPT_EOL 0 /* End of options */
164 #define TCPOPT_MSS 2 /* Segment size negotiating */
165 #define TCPOPT_WINDOW 3 /* Window scaling */
166 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
167 #define TCPOPT_SACK 5 /* SACK Block */
168 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
169 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
170
171 /*
172 * TCP option lengths
173 */
174
175 #define TCPOLEN_MSS 4
176 #define TCPOLEN_WINDOW 3
177 #define TCPOLEN_SACK_PERM 2
178 #define TCPOLEN_TIMESTAMP 10
179 #define TCPOLEN_MD5SIG 18
180
181 /* But this is what stacks really send out. */
182 #define TCPOLEN_TSTAMP_ALIGNED 12
183 #define TCPOLEN_WSCALE_ALIGNED 4
184 #define TCPOLEN_SACKPERM_ALIGNED 4
185 #define TCPOLEN_SACK_BASE 2
186 #define TCPOLEN_SACK_BASE_ALIGNED 4
187 #define TCPOLEN_SACK_PERBLOCK 8
188 #define TCPOLEN_MD5SIG_ALIGNED 20
189 #define TCPOLEN_MSS_ALIGNED 4
190
191 /* Flags in tp->nonagle */
192 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
193 #define TCP_NAGLE_CORK 2 /* Socket is corked */
194 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
195
196 extern struct inet_timewait_death_row tcp_death_row;
197
198 /* sysctl variables for tcp */
199 extern int sysctl_tcp_timestamps;
200 extern int sysctl_tcp_window_scaling;
201 extern int sysctl_tcp_sack;
202 extern int sysctl_tcp_fin_timeout;
203 extern int sysctl_tcp_keepalive_time;
204 extern int sysctl_tcp_keepalive_probes;
205 extern int sysctl_tcp_keepalive_intvl;
206 extern int sysctl_tcp_syn_retries;
207 extern int sysctl_tcp_synack_retries;
208 extern int sysctl_tcp_retries1;
209 extern int sysctl_tcp_retries2;
210 extern int sysctl_tcp_orphan_retries;
211 extern int sysctl_tcp_syncookies;
212 extern int sysctl_tcp_retrans_collapse;
213 extern int sysctl_tcp_stdurg;
214 extern int sysctl_tcp_rfc1337;
215 extern int sysctl_tcp_abort_on_overflow;
216 extern int sysctl_tcp_max_orphans;
217 extern int sysctl_tcp_fack;
218 extern int sysctl_tcp_reordering;
219 extern int sysctl_tcp_ecn;
220 extern int sysctl_tcp_dsack;
221 extern int sysctl_tcp_mem[3];
222 extern int sysctl_tcp_wmem[3];
223 extern int sysctl_tcp_rmem[3];
224 extern int sysctl_tcp_app_win;
225 extern int sysctl_tcp_adv_win_scale;
226 extern int sysctl_tcp_tw_reuse;
227 extern int sysctl_tcp_frto;
228 extern int sysctl_tcp_frto_response;
229 extern int sysctl_tcp_low_latency;
230 extern int sysctl_tcp_dma_copybreak;
231 extern int sysctl_tcp_nometrics_save;
232 extern int sysctl_tcp_moderate_rcvbuf;
233 extern int sysctl_tcp_tso_win_divisor;
234 extern int sysctl_tcp_abc;
235 extern int sysctl_tcp_mtu_probing;
236 extern int sysctl_tcp_base_mss;
237 extern int sysctl_tcp_workaround_signed_windows;
238 extern int sysctl_tcp_slow_start_after_idle;
239 extern int sysctl_tcp_max_ssthresh;
240
241 extern atomic_t tcp_memory_allocated;
242 extern struct percpu_counter tcp_sockets_allocated;
243 extern int tcp_memory_pressure;
244
245 /*
246 * The next routines deal with comparing 32 bit unsigned ints
247 * and worry about wraparound (automatic with unsigned arithmetic).
248 */
249
250 static inline int before(__u32 seq1, __u32 seq2)
251 {
252 return (__s32)(seq1-seq2) < 0;
253 }
254 #define after(seq2, seq1) before(seq1, seq2)
255
256 /* is s2<=s1<=s3 ? */
257 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
258 {
259 return seq3 - seq2 >= seq1 - seq2;
260 }
261
262 static inline int tcp_too_many_orphans(struct sock *sk, int num)
263 {
264 return (num > sysctl_tcp_max_orphans) ||
265 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
266 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
267 }
268
269 /* syncookies: remember time of last synqueue overflow */
270 static inline void tcp_synq_overflow(struct sock *sk)
271 {
272 tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies;
273 }
274
275 /* syncookies: no recent synqueue overflow on this listening socket? */
276 static inline int tcp_synq_no_recent_overflow(const struct sock *sk)
277 {
278 unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp;
279 return time_after(jiffies, last_overflow + TCP_TIMEOUT_INIT);
280 }
281
282 extern struct proto tcp_prot;
283
284 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
285 #define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field)
286 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
287 #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
288
289 extern void tcp_v4_err(struct sk_buff *skb, u32);
290
291 extern void tcp_shutdown (struct sock *sk, int how);
292
293 extern int tcp_v4_rcv(struct sk_buff *skb);
294
295 extern int tcp_v4_remember_stamp(struct sock *sk);
296
297 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
298
299 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
300 struct msghdr *msg, size_t size);
301 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
302
303 extern int tcp_ioctl(struct sock *sk,
304 int cmd,
305 unsigned long arg);
306
307 extern int tcp_rcv_state_process(struct sock *sk,
308 struct sk_buff *skb,
309 struct tcphdr *th,
310 unsigned len);
311
312 extern int tcp_rcv_established(struct sock *sk,
313 struct sk_buff *skb,
314 struct tcphdr *th,
315 unsigned len);
316
317 extern void tcp_rcv_space_adjust(struct sock *sk);
318
319 extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
320
321 extern int tcp_twsk_unique(struct sock *sk,
322 struct sock *sktw, void *twp);
323
324 extern void tcp_twsk_destructor(struct sock *sk);
325
326 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
327 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
328
329 static inline void tcp_dec_quickack_mode(struct sock *sk,
330 const unsigned int pkts)
331 {
332 struct inet_connection_sock *icsk = inet_csk(sk);
333
334 if (icsk->icsk_ack.quick) {
335 if (pkts >= icsk->icsk_ack.quick) {
336 icsk->icsk_ack.quick = 0;
337 /* Leaving quickack mode we deflate ATO. */
338 icsk->icsk_ack.ato = TCP_ATO_MIN;
339 } else
340 icsk->icsk_ack.quick -= pkts;
341 }
342 }
343
344 extern void tcp_enter_quickack_mode(struct sock *sk);
345
346 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
347 {
348 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
349 }
350
351 #define TCP_ECN_OK 1
352 #define TCP_ECN_QUEUE_CWR 2
353 #define TCP_ECN_DEMAND_CWR 4
354
355 static __inline__ void
356 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
357 {
358 if (sysctl_tcp_ecn && th->ece && th->cwr)
359 inet_rsk(req)->ecn_ok = 1;
360 }
361
362 enum tcp_tw_status
363 {
364 TCP_TW_SUCCESS = 0,
365 TCP_TW_RST = 1,
366 TCP_TW_ACK = 2,
367 TCP_TW_SYN = 3
368 };
369
370
371 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
372 struct sk_buff *skb,
373 const struct tcphdr *th);
374
375 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
376 struct request_sock *req,
377 struct request_sock **prev);
378 extern int tcp_child_process(struct sock *parent,
379 struct sock *child,
380 struct sk_buff *skb);
381 extern int tcp_use_frto(struct sock *sk);
382 extern void tcp_enter_frto(struct sock *sk);
383 extern void tcp_enter_loss(struct sock *sk, int how);
384 extern void tcp_clear_retrans(struct tcp_sock *tp);
385 extern void tcp_update_metrics(struct sock *sk);
386
387 extern void tcp_close(struct sock *sk,
388 long timeout);
389 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
390
391 extern int tcp_getsockopt(struct sock *sk, int level,
392 int optname,
393 char __user *optval,
394 int __user *optlen);
395 extern int tcp_setsockopt(struct sock *sk, int level,
396 int optname, char __user *optval,
397 unsigned int optlen);
398 extern int compat_tcp_getsockopt(struct sock *sk,
399 int level, int optname,
400 char __user *optval, int __user *optlen);
401 extern int compat_tcp_setsockopt(struct sock *sk,
402 int level, int optname,
403 char __user *optval, unsigned int optlen);
404 extern void tcp_set_keepalive(struct sock *sk, int val);
405 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
406 struct msghdr *msg,
407 size_t len, int nonblock,
408 int flags, int *addr_len);
409
410 extern void tcp_parse_options(struct sk_buff *skb,
411 struct tcp_options_received *opt_rx,
412 int estab);
413
414 extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
415
416 /*
417 * TCP v4 functions exported for the inet6 API
418 */
419
420 extern void tcp_v4_send_check(struct sock *sk, int len,
421 struct sk_buff *skb);
422
423 extern int tcp_v4_conn_request(struct sock *sk,
424 struct sk_buff *skb);
425
426 extern struct sock * tcp_create_openreq_child(struct sock *sk,
427 struct request_sock *req,
428 struct sk_buff *skb);
429
430 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
431 struct sk_buff *skb,
432 struct request_sock *req,
433 struct dst_entry *dst);
434
435 extern int tcp_v4_do_rcv(struct sock *sk,
436 struct sk_buff *skb);
437
438 extern int tcp_v4_connect(struct sock *sk,
439 struct sockaddr *uaddr,
440 int addr_len);
441
442 extern int tcp_connect(struct sock *sk);
443
444 extern struct sk_buff * tcp_make_synack(struct sock *sk,
445 struct dst_entry *dst,
446 struct request_sock *req);
447
448 extern int tcp_disconnect(struct sock *sk, int flags);
449
450
451 /* From syncookies.c */
452 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
453 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
454 struct ip_options *opt);
455 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
456 __u16 *mss);
457
458 extern __u32 cookie_init_timestamp(struct request_sock *req);
459 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
460
461 /* From net/ipv6/syncookies.c */
462 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
463 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
464 __u16 *mss);
465
466 /* tcp_output.c */
467
468 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
469 int nonagle);
470 extern int tcp_may_send_now(struct sock *sk);
471 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
472 extern void tcp_retransmit_timer(struct sock *sk);
473 extern void tcp_xmit_retransmit_queue(struct sock *);
474 extern void tcp_simple_retransmit(struct sock *);
475 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
476 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
477
478 extern void tcp_send_probe0(struct sock *);
479 extern void tcp_send_partial(struct sock *);
480 extern int tcp_write_wakeup(struct sock *);
481 extern void tcp_send_fin(struct sock *sk);
482 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
483 extern int tcp_send_synack(struct sock *);
484 extern void tcp_push_one(struct sock *, unsigned int mss_now);
485 extern void tcp_send_ack(struct sock *sk);
486 extern void tcp_send_delayed_ack(struct sock *sk);
487
488 /* tcp_input.c */
489 extern void tcp_cwnd_application_limited(struct sock *sk);
490
491 /* tcp_timer.c */
492 extern void tcp_init_xmit_timers(struct sock *);
493 static inline void tcp_clear_xmit_timers(struct sock *sk)
494 {
495 inet_csk_clear_xmit_timers(sk);
496 }
497
498 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
499 extern unsigned int tcp_current_mss(struct sock *sk);
500
501 /* Bound MSS / TSO packet size with the half of the window */
502 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize)
503 {
504 if (tp->max_window && pktsize > (tp->max_window >> 1))
505 return max(tp->max_window >> 1, 68U - tp->tcp_header_len);
506 else
507 return pktsize;
508 }
509
510 /* tcp.c */
511 extern void tcp_get_info(struct sock *, struct tcp_info *);
512
513 /* Read 'sendfile()'-style from a TCP socket */
514 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
515 unsigned int, size_t);
516 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
517 sk_read_actor_t recv_actor);
518
519 extern void tcp_initialize_rcv_mss(struct sock *sk);
520
521 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
522 extern int tcp_mss_to_mtu(struct sock *sk, int mss);
523 extern void tcp_mtup_init(struct sock *sk);
524
525 static inline void tcp_bound_rto(const struct sock *sk)
526 {
527 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX)
528 inet_csk(sk)->icsk_rto = TCP_RTO_MAX;
529 }
530
531 static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
532 {
533 return (tp->srtt >> 3) + tp->rttvar;
534 }
535
536 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
537 {
538 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
539 ntohl(TCP_FLAG_ACK) |
540 snd_wnd);
541 }
542
543 static inline void tcp_fast_path_on(struct tcp_sock *tp)
544 {
545 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
546 }
547
548 static inline void tcp_fast_path_check(struct sock *sk)
549 {
550 struct tcp_sock *tp = tcp_sk(sk);
551
552 if (skb_queue_empty(&tp->out_of_order_queue) &&
553 tp->rcv_wnd &&
554 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
555 !tp->urg_data)
556 tcp_fast_path_on(tp);
557 }
558
559 /* Compute the actual rto_min value */
560 static inline u32 tcp_rto_min(struct sock *sk)
561 {
562 struct dst_entry *dst = __sk_dst_get(sk);
563 u32 rto_min = TCP_RTO_MIN;
564
565 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))
566 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN);
567 return rto_min;
568 }
569
570 /* Compute the actual receive window we are currently advertising.
571 * Rcv_nxt can be after the window if our peer push more data
572 * than the offered window.
573 */
574 static inline u32 tcp_receive_window(const struct tcp_sock *tp)
575 {
576 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
577
578 if (win < 0)
579 win = 0;
580 return (u32) win;
581 }
582
583 /* Choose a new window, without checks for shrinking, and without
584 * scaling applied to the result. The caller does these things
585 * if necessary. This is a "raw" window selection.
586 */
587 extern u32 __tcp_select_window(struct sock *sk);
588
589 /* TCP timestamps are only 32-bits, this causes a slight
590 * complication on 64-bit systems since we store a snapshot
591 * of jiffies in the buffer control blocks below. We decided
592 * to use only the low 32-bits of jiffies and hide the ugly
593 * casts with the following macro.
594 */
595 #define tcp_time_stamp ((__u32)(jiffies))
596
597 /* This is what the send packet queuing engine uses to pass
598 * TCP per-packet control information to the transmission
599 * code. We also store the host-order sequence numbers in
600 * here too. This is 36 bytes on 32-bit architectures,
601 * 40 bytes on 64-bit machines, if this grows please adjust
602 * skbuff.h:skbuff->cb[xxx] size appropriately.
603 */
604 struct tcp_skb_cb {
605 union {
606 struct inet_skb_parm h4;
607 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
608 struct inet6_skb_parm h6;
609 #endif
610 } header; /* For incoming frames */
611 __u32 seq; /* Starting sequence number */
612 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
613 __u32 when; /* used to compute rtt's */
614 __u8 flags; /* TCP header flags. */
615
616 /* NOTE: These must match up to the flags byte in a
617 * real TCP header.
618 */
619 #define TCPCB_FLAG_FIN 0x01
620 #define TCPCB_FLAG_SYN 0x02
621 #define TCPCB_FLAG_RST 0x04
622 #define TCPCB_FLAG_PSH 0x08
623 #define TCPCB_FLAG_ACK 0x10
624 #define TCPCB_FLAG_URG 0x20
625 #define TCPCB_FLAG_ECE 0x40
626 #define TCPCB_FLAG_CWR 0x80
627
628 __u8 sacked; /* State flags for SACK/FACK. */
629 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
630 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
631 #define TCPCB_LOST 0x04 /* SKB is lost */
632 #define TCPCB_TAGBITS 0x07 /* All tag bits */
633
634 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
635 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
636
637 __u32 ack_seq; /* Sequence number ACK'd */
638 };
639
640 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
641
642 /* Due to TSO, an SKB can be composed of multiple actual
643 * packets. To keep these tracked properly, we use this.
644 */
645 static inline int tcp_skb_pcount(const struct sk_buff *skb)
646 {
647 return skb_shinfo(skb)->gso_segs;
648 }
649
650 /* This is valid iff tcp_skb_pcount() > 1. */
651 static inline int tcp_skb_mss(const struct sk_buff *skb)
652 {
653 return skb_shinfo(skb)->gso_size;
654 }
655
656 /* Events passed to congestion control interface */
657 enum tcp_ca_event {
658 CA_EVENT_TX_START, /* first transmit when no packets in flight */
659 CA_EVENT_CWND_RESTART, /* congestion window restart */
660 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
661 CA_EVENT_FRTO, /* fast recovery timeout */
662 CA_EVENT_LOSS, /* loss timeout */
663 CA_EVENT_FAST_ACK, /* in sequence ack */
664 CA_EVENT_SLOW_ACK, /* other ack */
665 };
666
667 /*
668 * Interface for adding new TCP congestion control handlers
669 */
670 #define TCP_CA_NAME_MAX 16
671 #define TCP_CA_MAX 128
672 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
673
674 #define TCP_CONG_NON_RESTRICTED 0x1
675 #define TCP_CONG_RTT_STAMP 0x2
676
677 struct tcp_congestion_ops {
678 struct list_head list;
679 unsigned long flags;
680
681 /* initialize private data (optional) */
682 void (*init)(struct sock *sk);
683 /* cleanup private data (optional) */
684 void (*release)(struct sock *sk);
685
686 /* return slow start threshold (required) */
687 u32 (*ssthresh)(struct sock *sk);
688 /* lower bound for congestion window (optional) */
689 u32 (*min_cwnd)(const struct sock *sk);
690 /* do new cwnd calculation (required) */
691 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
692 /* call before changing ca_state (optional) */
693 void (*set_state)(struct sock *sk, u8 new_state);
694 /* call when cwnd event occurs (optional) */
695 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
696 /* new value of cwnd after loss (optional) */
697 u32 (*undo_cwnd)(struct sock *sk);
698 /* hook for packet ack accounting (optional) */
699 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
700 /* get info for inet_diag (optional) */
701 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
702
703 char name[TCP_CA_NAME_MAX];
704 struct module *owner;
705 };
706
707 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
708 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
709
710 extern void tcp_init_congestion_control(struct sock *sk);
711 extern void tcp_cleanup_congestion_control(struct sock *sk);
712 extern int tcp_set_default_congestion_control(const char *name);
713 extern void tcp_get_default_congestion_control(char *name);
714 extern void tcp_get_available_congestion_control(char *buf, size_t len);
715 extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
716 extern int tcp_set_allowed_congestion_control(char *allowed);
717 extern int tcp_set_congestion_control(struct sock *sk, const char *name);
718 extern void tcp_slow_start(struct tcp_sock *tp);
719 extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w);
720
721 extern struct tcp_congestion_ops tcp_init_congestion_ops;
722 extern u32 tcp_reno_ssthresh(struct sock *sk);
723 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
724 extern u32 tcp_reno_min_cwnd(const struct sock *sk);
725 extern struct tcp_congestion_ops tcp_reno;
726
727 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
728 {
729 struct inet_connection_sock *icsk = inet_csk(sk);
730
731 if (icsk->icsk_ca_ops->set_state)
732 icsk->icsk_ca_ops->set_state(sk, ca_state);
733 icsk->icsk_ca_state = ca_state;
734 }
735
736 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
737 {
738 const struct inet_connection_sock *icsk = inet_csk(sk);
739
740 if (icsk->icsk_ca_ops->cwnd_event)
741 icsk->icsk_ca_ops->cwnd_event(sk, event);
742 }
743
744 /* These functions determine how the current flow behaves in respect of SACK
745 * handling. SACK is negotiated with the peer, and therefore it can vary
746 * between different flows.
747 *
748 * tcp_is_sack - SACK enabled
749 * tcp_is_reno - No SACK
750 * tcp_is_fack - FACK enabled, implies SACK enabled
751 */
752 static inline int tcp_is_sack(const struct tcp_sock *tp)
753 {
754 return tp->rx_opt.sack_ok;
755 }
756
757 static inline int tcp_is_reno(const struct tcp_sock *tp)
758 {
759 return !tcp_is_sack(tp);
760 }
761
762 static inline int tcp_is_fack(const struct tcp_sock *tp)
763 {
764 return tp->rx_opt.sack_ok & 2;
765 }
766
767 static inline void tcp_enable_fack(struct tcp_sock *tp)
768 {
769 tp->rx_opt.sack_ok |= 2;
770 }
771
772 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
773 {
774 return tp->sacked_out + tp->lost_out;
775 }
776
777 /* This determines how many packets are "in the network" to the best
778 * of our knowledge. In many cases it is conservative, but where
779 * detailed information is available from the receiver (via SACK
780 * blocks etc.) we can make more aggressive calculations.
781 *
782 * Use this for decisions involving congestion control, use just
783 * tp->packets_out to determine if the send queue is empty or not.
784 *
785 * Read this equation as:
786 *
787 * "Packets sent once on transmission queue" MINUS
788 * "Packets left network, but not honestly ACKed yet" PLUS
789 * "Packets fast retransmitted"
790 */
791 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
792 {
793 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
794 }
795
796 #define TCP_INFINITE_SSTHRESH 0x7fffffff
797
798 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp)
799 {
800 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH;
801 }
802
803 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
804 * The exception is rate halving phase, when cwnd is decreasing towards
805 * ssthresh.
806 */
807 static inline __u32 tcp_current_ssthresh(const struct sock *sk)
808 {
809 const struct tcp_sock *tp = tcp_sk(sk);
810 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
811 return tp->snd_ssthresh;
812 else
813 return max(tp->snd_ssthresh,
814 ((tp->snd_cwnd >> 1) +
815 (tp->snd_cwnd >> 2)));
816 }
817
818 /* Use define here intentionally to get WARN_ON location shown at the caller */
819 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
820
821 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
822 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
823
824 /* Slow start with delack produces 3 packets of burst, so that
825 * it is safe "de facto". This will be the default - same as
826 * the default reordering threshold - but if reordering increases,
827 * we must be able to allow cwnd to burst at least this much in order
828 * to not pull it back when holes are filled.
829 */
830 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
831 {
832 return tp->reordering;
833 }
834
835 /* Returns end sequence number of the receiver's advertised window */
836 static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
837 {
838 return tp->snd_una + tp->snd_wnd;
839 }
840 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
841
842 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
843 const struct sk_buff *skb)
844 {
845 if (skb->len < mss)
846 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
847 }
848
849 static inline void tcp_check_probe_timer(struct sock *sk)
850 {
851 struct tcp_sock *tp = tcp_sk(sk);
852 const struct inet_connection_sock *icsk = inet_csk(sk);
853
854 if (!tp->packets_out && !icsk->icsk_pending)
855 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
856 icsk->icsk_rto, TCP_RTO_MAX);
857 }
858
859 static inline void tcp_push_pending_frames(struct sock *sk)
860 {
861 struct tcp_sock *tp = tcp_sk(sk);
862
863 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle);
864 }
865
866 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)
867 {
868 tp->snd_wl1 = seq;
869 }
870
871 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq)
872 {
873 tp->snd_wl1 = seq;
874 }
875
876 /*
877 * Calculate(/check) TCP checksum
878 */
879 static inline __sum16 tcp_v4_check(int len, __be32 saddr,
880 __be32 daddr, __wsum base)
881 {
882 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
883 }
884
885 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
886 {
887 return __skb_checksum_complete(skb);
888 }
889
890 static inline int tcp_checksum_complete(struct sk_buff *skb)
891 {
892 return !skb_csum_unnecessary(skb) &&
893 __tcp_checksum_complete(skb);
894 }
895
896 /* Prequeue for VJ style copy to user, combined with checksumming. */
897
898 static inline void tcp_prequeue_init(struct tcp_sock *tp)
899 {
900 tp->ucopy.task = NULL;
901 tp->ucopy.len = 0;
902 tp->ucopy.memory = 0;
903 skb_queue_head_init(&tp->ucopy.prequeue);
904 #ifdef CONFIG_NET_DMA
905 tp->ucopy.dma_chan = NULL;
906 tp->ucopy.wakeup = 0;
907 tp->ucopy.pinned_list = NULL;
908 tp->ucopy.dma_cookie = 0;
909 #endif
910 }
911
912 /* Packet is added to VJ-style prequeue for processing in process
913 * context, if a reader task is waiting. Apparently, this exciting
914 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
915 * failed somewhere. Latency? Burstiness? Well, at least now we will
916 * see, why it failed. 8)8) --ANK
917 *
918 * NOTE: is this not too big to inline?
919 */
920 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
921 {
922 struct tcp_sock *tp = tcp_sk(sk);
923
924 if (sysctl_tcp_low_latency || !tp->ucopy.task)
925 return 0;
926
927 __skb_queue_tail(&tp->ucopy.prequeue, skb);
928 tp->ucopy.memory += skb->truesize;
929 if (tp->ucopy.memory > sk->sk_rcvbuf) {
930 struct sk_buff *skb1;
931
932 BUG_ON(sock_owned_by_user(sk));
933
934 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
935 sk_backlog_rcv(sk, skb1);
936 NET_INC_STATS_BH(sock_net(sk),
937 LINUX_MIB_TCPPREQUEUEDROPPED);
938 }
939
940 tp->ucopy.memory = 0;
941 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
942 wake_up_interruptible_poll(sk->sk_sleep,
943 POLLIN | POLLRDNORM | POLLRDBAND);
944 if (!inet_csk_ack_scheduled(sk))
945 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
946 (3 * tcp_rto_min(sk)) / 4,
947 TCP_RTO_MAX);
948 }
949 return 1;
950 }
951
952
953 #undef STATE_TRACE
954
955 #ifdef STATE_TRACE
956 static const char *statename[]={
957 "Unused","Established","Syn Sent","Syn Recv",
958 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
959 "Close Wait","Last ACK","Listen","Closing"
960 };
961 #endif
962 extern void tcp_set_state(struct sock *sk, int state);
963
964 extern void tcp_done(struct sock *sk);
965
966 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
967 {
968 rx_opt->dsack = 0;
969 rx_opt->num_sacks = 0;
970 }
971
972 /* Determine a window scaling and initial window to offer. */
973 extern void tcp_select_initial_window(int __space, __u32 mss,
974 __u32 *rcv_wnd, __u32 *window_clamp,
975 int wscale_ok, __u8 *rcv_wscale);
976
977 static inline int tcp_win_from_space(int space)
978 {
979 return sysctl_tcp_adv_win_scale<=0 ?
980 (space>>(-sysctl_tcp_adv_win_scale)) :
981 space - (space>>sysctl_tcp_adv_win_scale);
982 }
983
984 /* Note: caller must be prepared to deal with negative returns */
985 static inline int tcp_space(const struct sock *sk)
986 {
987 return tcp_win_from_space(sk->sk_rcvbuf -
988 atomic_read(&sk->sk_rmem_alloc));
989 }
990
991 static inline int tcp_full_space(const struct sock *sk)
992 {
993 return tcp_win_from_space(sk->sk_rcvbuf);
994 }
995
996 static inline void tcp_openreq_init(struct request_sock *req,
997 struct tcp_options_received *rx_opt,
998 struct sk_buff *skb)
999 {
1000 struct inet_request_sock *ireq = inet_rsk(req);
1001
1002 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
1003 req->cookie_ts = 0;
1004 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
1005 req->mss = rx_opt->mss_clamp;
1006 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
1007 ireq->tstamp_ok = rx_opt->tstamp_ok;
1008 ireq->sack_ok = rx_opt->sack_ok;
1009 ireq->snd_wscale = rx_opt->snd_wscale;
1010 ireq->wscale_ok = rx_opt->wscale_ok;
1011 ireq->acked = 0;
1012 ireq->ecn_ok = 0;
1013 ireq->rmt_port = tcp_hdr(skb)->source;
1014 ireq->loc_port = tcp_hdr(skb)->dest;
1015 }
1016
1017 extern void tcp_enter_memory_pressure(struct sock *sk);
1018
1019 static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1020 {
1021 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
1022 }
1023
1024 static inline int keepalive_time_when(const struct tcp_sock *tp)
1025 {
1026 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
1027 }
1028
1029 static inline int keepalive_probes(const struct tcp_sock *tp)
1030 {
1031 return tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
1032 }
1033
1034 static inline int tcp_fin_time(const struct sock *sk)
1035 {
1036 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
1037 const int rto = inet_csk(sk)->icsk_rto;
1038
1039 if (fin_timeout < (rto << 2) - (rto >> 1))
1040 fin_timeout = (rto << 2) - (rto >> 1);
1041
1042 return fin_timeout;
1043 }
1044
1045 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt,
1046 int paws_win)
1047 {
1048 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
1049 return 1;
1050 if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))
1051 return 1;
1052
1053 return 0;
1054 }
1055
1056 static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt,
1057 int rst)
1058 {
1059 if (tcp_paws_check(rx_opt, 0))
1060 return 0;
1061
1062 /* RST segments are not recommended to carry timestamp,
1063 and, if they do, it is recommended to ignore PAWS because
1064 "their cleanup function should take precedence over timestamps."
1065 Certainly, it is mistake. It is necessary to understand the reasons
1066 of this constraint to relax it: if peer reboots, clock may go
1067 out-of-sync and half-open connections will not be reset.
1068 Actually, the problem would be not existing if all
1069 the implementations followed draft about maintaining clock
1070 via reboots. Linux-2.2 DOES NOT!
1071
1072 However, we can relax time bounds for RST segments to MSL.
1073 */
1074 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1075 return 0;
1076 return 1;
1077 }
1078
1079 #define TCP_CHECK_TIMER(sk) do { } while (0)
1080
1081 static inline void tcp_mib_init(struct net *net)
1082 {
1083 /* See RFC 2012 */
1084 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
1085 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1086 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1087 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
1088 }
1089
1090 /* from STCP */
1091 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
1092 {
1093 tp->lost_skb_hint = NULL;
1094 tp->scoreboard_skb_hint = NULL;
1095 }
1096
1097 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1098 {
1099 tcp_clear_retrans_hints_partial(tp);
1100 tp->retransmit_skb_hint = NULL;
1101 }
1102
1103 /* MD5 Signature */
1104 struct crypto_hash;
1105
1106 /* - key database */
1107 struct tcp_md5sig_key {
1108 u8 *key;
1109 u8 keylen;
1110 };
1111
1112 struct tcp4_md5sig_key {
1113 struct tcp_md5sig_key base;
1114 __be32 addr;
1115 };
1116
1117 struct tcp6_md5sig_key {
1118 struct tcp_md5sig_key base;
1119 #if 0
1120 u32 scope_id; /* XXX */
1121 #endif
1122 struct in6_addr addr;
1123 };
1124
1125 /* - sock block */
1126 struct tcp_md5sig_info {
1127 struct tcp4_md5sig_key *keys4;
1128 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1129 struct tcp6_md5sig_key *keys6;
1130 u32 entries6;
1131 u32 alloced6;
1132 #endif
1133 u32 entries4;
1134 u32 alloced4;
1135 };
1136
1137 /* - pseudo header */
1138 struct tcp4_pseudohdr {
1139 __be32 saddr;
1140 __be32 daddr;
1141 __u8 pad;
1142 __u8 protocol;
1143 __be16 len;
1144 };
1145
1146 struct tcp6_pseudohdr {
1147 struct in6_addr saddr;
1148 struct in6_addr daddr;
1149 __be32 len;
1150 __be32 protocol; /* including padding */
1151 };
1152
1153 union tcp_md5sum_block {
1154 struct tcp4_pseudohdr ip4;
1155 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1156 struct tcp6_pseudohdr ip6;
1157 #endif
1158 };
1159
1160 /* - pool: digest algorithm, hash description and scratch buffer */
1161 struct tcp_md5sig_pool {
1162 struct hash_desc md5_desc;
1163 union tcp_md5sum_block md5_blk;
1164 };
1165
1166 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1167
1168 /* - functions */
1169 extern int tcp_v4_md5_hash_skb(char *md5_hash,
1170 struct tcp_md5sig_key *key,
1171 struct sock *sk,
1172 struct request_sock *req,
1173 struct sk_buff *skb);
1174
1175 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1176 struct sock *addr_sk);
1177
1178 extern int tcp_v4_md5_do_add(struct sock *sk,
1179 __be32 addr,
1180 u8 *newkey,
1181 u8 newkeylen);
1182
1183 extern int tcp_v4_md5_do_del(struct sock *sk,
1184 __be32 addr);
1185
1186 #ifdef CONFIG_TCP_MD5SIG
1187 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1188 &(struct tcp_md5sig_key) { \
1189 .key = (twsk)->tw_md5_key, \
1190 .keylen = (twsk)->tw_md5_keylen, \
1191 } : NULL)
1192 #else
1193 #define tcp_twsk_md5_key(twsk) NULL
1194 #endif
1195
1196 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(struct sock *);
1197 extern void tcp_free_md5sig_pool(void);
1198
1199 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1200 extern void __tcp_put_md5sig_pool(void);
1201 extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *);
1202 extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *,
1203 unsigned header_len);
1204 extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1205 struct tcp_md5sig_key *key);
1206
1207 static inline
1208 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1209 {
1210 int cpu = get_cpu();
1211 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1212 if (!ret)
1213 put_cpu();
1214 return ret;
1215 }
1216
1217 static inline void tcp_put_md5sig_pool(void)
1218 {
1219 __tcp_put_md5sig_pool();
1220 put_cpu();
1221 }
1222
1223 /* write queue abstraction */
1224 static inline void tcp_write_queue_purge(struct sock *sk)
1225 {
1226 struct sk_buff *skb;
1227
1228 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1229 sk_wmem_free_skb(sk, skb);
1230 sk_mem_reclaim(sk);
1231 }
1232
1233 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1234 {
1235 return skb_peek(&sk->sk_write_queue);
1236 }
1237
1238 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1239 {
1240 return skb_peek_tail(&sk->sk_write_queue);
1241 }
1242
1243 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1244 {
1245 return skb_queue_next(&sk->sk_write_queue, skb);
1246 }
1247
1248 static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_buff *skb)
1249 {
1250 return skb_queue_prev(&sk->sk_write_queue, skb);
1251 }
1252
1253 #define tcp_for_write_queue(skb, sk) \
1254 skb_queue_walk(&(sk)->sk_write_queue, skb)
1255
1256 #define tcp_for_write_queue_from(skb, sk) \
1257 skb_queue_walk_from(&(sk)->sk_write_queue, skb)
1258
1259 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1260 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
1261
1262 /* This function calculates a "timeout" which is equivalent to the timeout of a
1263 * TCP connection after "boundary" unsucessful, exponentially backed-off
1264 * retransmissions with an initial RTO of TCP_RTO_MIN.
1265 */
1266 static inline bool retransmits_timed_out(const struct sock *sk,
1267 unsigned int boundary)
1268 {
1269 unsigned int timeout, linear_backoff_thresh;
1270
1271 if (!inet_csk(sk)->icsk_retransmits)
1272 return false;
1273
1274 linear_backoff_thresh = ilog2(TCP_RTO_MAX/TCP_RTO_MIN);
1275
1276 if (boundary <= linear_backoff_thresh)
1277 timeout = ((2 << boundary) - 1) * TCP_RTO_MIN;
1278 else
1279 timeout = ((2 << linear_backoff_thresh) - 1) * TCP_RTO_MIN +
1280 (boundary - linear_backoff_thresh) * TCP_RTO_MAX;
1281
1282 return (tcp_time_stamp - tcp_sk(sk)->retrans_stamp) >= timeout;
1283 }
1284
1285 static inline struct sk_buff *tcp_send_head(struct sock *sk)
1286 {
1287 return sk->sk_send_head;
1288 }
1289
1290 static inline bool tcp_skb_is_last(const struct sock *sk,
1291 const struct sk_buff *skb)
1292 {
1293 return skb_queue_is_last(&sk->sk_write_queue, skb);
1294 }
1295
1296 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1297 {
1298 if (tcp_skb_is_last(sk, skb))
1299 sk->sk_send_head = NULL;
1300 else
1301 sk->sk_send_head = tcp_write_queue_next(sk, skb);
1302 }
1303
1304 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1305 {
1306 if (sk->sk_send_head == skb_unlinked)
1307 sk->sk_send_head = NULL;
1308 }
1309
1310 static inline void tcp_init_send_head(struct sock *sk)
1311 {
1312 sk->sk_send_head = NULL;
1313 }
1314
1315 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1316 {
1317 __skb_queue_tail(&sk->sk_write_queue, skb);
1318 }
1319
1320 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1321 {
1322 __tcp_add_write_queue_tail(sk, skb);
1323
1324 /* Queue it, remembering where we must start sending. */
1325 if (sk->sk_send_head == NULL) {
1326 sk->sk_send_head = skb;
1327
1328 if (tcp_sk(sk)->highest_sack == NULL)
1329 tcp_sk(sk)->highest_sack = skb;
1330 }
1331 }
1332
1333 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1334 {
1335 __skb_queue_head(&sk->sk_write_queue, skb);
1336 }
1337
1338 /* Insert buff after skb on the write queue of sk. */
1339 static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1340 struct sk_buff *buff,
1341 struct sock *sk)
1342 {
1343 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1344 }
1345
1346 /* Insert new before skb on the write queue of sk. */
1347 static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1348 struct sk_buff *skb,
1349 struct sock *sk)
1350 {
1351 __skb_queue_before(&sk->sk_write_queue, skb, new);
1352
1353 if (sk->sk_send_head == skb)
1354 sk->sk_send_head = new;
1355 }
1356
1357 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1358 {
1359 __skb_unlink(skb, &sk->sk_write_queue);
1360 }
1361
1362 static inline int tcp_write_queue_empty(struct sock *sk)
1363 {
1364 return skb_queue_empty(&sk->sk_write_queue);
1365 }
1366
1367 /* Start sequence of the highest skb with SACKed bit, valid only if
1368 * sacked > 0 or when the caller has ensured validity by itself.
1369 */
1370 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1371 {
1372 if (!tp->sacked_out)
1373 return tp->snd_una;
1374
1375 if (tp->highest_sack == NULL)
1376 return tp->snd_nxt;
1377
1378 return TCP_SKB_CB(tp->highest_sack)->seq;
1379 }
1380
1381 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1382 {
1383 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1384 tcp_write_queue_next(sk, skb);
1385 }
1386
1387 static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1388 {
1389 return tcp_sk(sk)->highest_sack;
1390 }
1391
1392 static inline void tcp_highest_sack_reset(struct sock *sk)
1393 {
1394 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1395 }
1396
1397 /* Called when old skb is about to be deleted (to be combined with new skb) */
1398 static inline void tcp_highest_sack_combine(struct sock *sk,
1399 struct sk_buff *old,
1400 struct sk_buff *new)
1401 {
1402 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1403 tcp_sk(sk)->highest_sack = new;
1404 }
1405
1406 /* /proc */
1407 enum tcp_seq_states {
1408 TCP_SEQ_STATE_LISTENING,
1409 TCP_SEQ_STATE_OPENREQ,
1410 TCP_SEQ_STATE_ESTABLISHED,
1411 TCP_SEQ_STATE_TIME_WAIT,
1412 };
1413
1414 struct tcp_seq_afinfo {
1415 char *name;
1416 sa_family_t family;
1417 struct file_operations seq_fops;
1418 struct seq_operations seq_ops;
1419 };
1420
1421 struct tcp_iter_state {
1422 struct seq_net_private p;
1423 sa_family_t family;
1424 enum tcp_seq_states state;
1425 struct sock *syn_wait_sk;
1426 int bucket, sbucket, num, uid;
1427 };
1428
1429 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1430 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1431
1432 extern struct request_sock_ops tcp_request_sock_ops;
1433 extern struct request_sock_ops tcp6_request_sock_ops;
1434
1435 extern void tcp_v4_destroy_sock(struct sock *sk);
1436
1437 extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1438 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1439 extern struct sk_buff **tcp_gro_receive(struct sk_buff **head,
1440 struct sk_buff *skb);
1441 extern struct sk_buff **tcp4_gro_receive(struct sk_buff **head,
1442 struct sk_buff *skb);
1443 extern int tcp_gro_complete(struct sk_buff *skb);
1444 extern int tcp4_gro_complete(struct sk_buff *skb);
1445
1446 #ifdef CONFIG_PROC_FS
1447 extern int tcp4_proc_init(void);
1448 extern void tcp4_proc_exit(void);
1449 #endif
1450
1451 /* TCP af-specific functions */
1452 struct tcp_sock_af_ops {
1453 #ifdef CONFIG_TCP_MD5SIG
1454 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1455 struct sock *addr_sk);
1456 int (*calc_md5_hash) (char *location,
1457 struct tcp_md5sig_key *md5,
1458 struct sock *sk,
1459 struct request_sock *req,
1460 struct sk_buff *skb);
1461 int (*md5_add) (struct sock *sk,
1462 struct sock *addr_sk,
1463 u8 *newkey,
1464 u8 len);
1465 int (*md5_parse) (struct sock *sk,
1466 char __user *optval,
1467 int optlen);
1468 #endif
1469 };
1470
1471 struct tcp_request_sock_ops {
1472 #ifdef CONFIG_TCP_MD5SIG
1473 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1474 struct request_sock *req);
1475 int (*calc_md5_hash) (char *location,
1476 struct tcp_md5sig_key *md5,
1477 struct sock *sk,
1478 struct request_sock *req,
1479 struct sk_buff *skb);
1480 #endif
1481 };
1482
1483 extern void tcp_v4_init(void);
1484 extern void tcp_init(void);
1485
1486 #endif /* _TCP_H */
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