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tcp: remove retransmit_skb_hint clearing from failure
[linux-block.git] / include / net / tcp.h
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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
47extern struct inet_hashinfo tcp_hashinfo;
48
49extern atomic_t tcp_orphan_count;
50extern void tcp_time_wait(struct sock *sk, int state, int timeo);
51
52#define MAX_TCP_HEADER (128 + MAX_HEADER)
53#define MAX_TCP_OPTION_SPACE 40
54
55/*
56 * Never offer a window over 32767 without using window scaling. Some
57 * poor stacks do signed 16bit maths!
58 */
59#define MAX_TCP_WINDOW 32767U
60
61/* Minimal accepted MSS. It is (60+60+8) - (20+20). */
62#define TCP_MIN_MSS 88U
63
64/* Minimal RCV_MSS. */
65#define TCP_MIN_RCVMSS 536U
66
67/* The least MTU to use for probing */
68#define TCP_BASE_MSS 512
69
70/* After receiving this amount of duplicate ACKs fast retransmit starts. */
71#define TCP_FASTRETRANS_THRESH 3
72
73/* Maximal reordering. */
74#define TCP_MAX_REORDERING 127
75
76/* Maximal number of ACKs sent quickly to accelerate slow-start. */
77#define TCP_MAX_QUICKACKS 16U
78
79/* urg_data states */
80#define TCP_URG_VALID 0x0100
81#define TCP_URG_NOTYET 0x0200
82#define TCP_URG_READ 0x0400
83
84#define TCP_RETR1 3 /*
85 * This is how many retries it does before it
86 * tries to figure out if the gateway is
87 * down. Minimal RFC value is 3; it corresponds
88 * to ~3sec-8min depending on RTO.
89 */
90
91#define TCP_RETR2 15 /*
92 * This should take at least
93 * 90 minutes to time out.
94 * RFC1122 says that the limit is 100 sec.
95 * 15 is ~13-30min depending on RTO.
96 */
97
98#define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
99 * connection: ~180sec is RFC minimum */
100
101#define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
102 * connection: ~180sec is RFC minimum */
103
104
105#define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
106 * socket. 7 is ~50sec-16min.
107 */
108
109
110#define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
111 * state, about 60 seconds */
112#define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
113 /* BSD style FIN_WAIT2 deadlock breaker.
114 * It used to be 3min, new value is 60sec,
115 * to combine FIN-WAIT-2 timeout with
116 * TIME-WAIT timer.
117 */
118
119#define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
120#if HZ >= 100
121#define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
122#define TCP_ATO_MIN ((unsigned)(HZ/25))
123#else
124#define TCP_DELACK_MIN 4U
125#define TCP_ATO_MIN 4U
126#endif
127#define TCP_RTO_MAX ((unsigned)(120*HZ))
128#define TCP_RTO_MIN ((unsigned)(HZ/5))
129#define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
130
131#define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
132 * for local resources.
133 */
134
135#define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
136#define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
137#define TCP_KEEPALIVE_INTVL (75*HZ)
138
139#define MAX_TCP_KEEPIDLE 32767
140#define MAX_TCP_KEEPINTVL 32767
141#define MAX_TCP_KEEPCNT 127
142#define MAX_TCP_SYNCNT 127
143
144#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
145
146#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
147#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
148 * after this time. It should be equal
149 * (or greater than) TCP_TIMEWAIT_LEN
150 * to provide reliability equal to one
151 * provided by timewait state.
152 */
153#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
154 * timestamps. It must be less than
155 * minimal timewait lifetime.
156 */
157/*
158 * TCP option
159 */
160
161#define TCPOPT_NOP 1 /* Padding */
162#define TCPOPT_EOL 0 /* End of options */
163#define TCPOPT_MSS 2 /* Segment size negotiating */
164#define TCPOPT_WINDOW 3 /* Window scaling */
165#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
166#define TCPOPT_SACK 5 /* SACK Block */
167#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
168#define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
169
170/*
171 * TCP option lengths
172 */
173
174#define TCPOLEN_MSS 4
175#define TCPOLEN_WINDOW 3
176#define TCPOLEN_SACK_PERM 2
177#define TCPOLEN_TIMESTAMP 10
178#define TCPOLEN_MD5SIG 18
179
180/* But this is what stacks really send out. */
181#define TCPOLEN_TSTAMP_ALIGNED 12
182#define TCPOLEN_WSCALE_ALIGNED 4
183#define TCPOLEN_SACKPERM_ALIGNED 4
184#define TCPOLEN_SACK_BASE 2
185#define TCPOLEN_SACK_BASE_ALIGNED 4
186#define TCPOLEN_SACK_PERBLOCK 8
187#define TCPOLEN_MD5SIG_ALIGNED 20
188#define TCPOLEN_MSS_ALIGNED 4
189
190/* Flags in tp->nonagle */
191#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
192#define TCP_NAGLE_CORK 2 /* Socket is corked */
193#define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */
194
195extern struct inet_timewait_death_row tcp_death_row;
196
197/* sysctl variables for tcp */
198extern int sysctl_tcp_timestamps;
199extern int sysctl_tcp_window_scaling;
200extern int sysctl_tcp_sack;
201extern int sysctl_tcp_fin_timeout;
202extern int sysctl_tcp_keepalive_time;
203extern int sysctl_tcp_keepalive_probes;
204extern int sysctl_tcp_keepalive_intvl;
205extern int sysctl_tcp_syn_retries;
206extern int sysctl_tcp_synack_retries;
207extern int sysctl_tcp_retries1;
208extern int sysctl_tcp_retries2;
209extern int sysctl_tcp_orphan_retries;
210extern int sysctl_tcp_syncookies;
211extern int sysctl_tcp_retrans_collapse;
212extern int sysctl_tcp_stdurg;
213extern int sysctl_tcp_rfc1337;
214extern int sysctl_tcp_abort_on_overflow;
215extern int sysctl_tcp_max_orphans;
216extern int sysctl_tcp_fack;
217extern int sysctl_tcp_reordering;
218extern int sysctl_tcp_ecn;
219extern int sysctl_tcp_dsack;
220extern int sysctl_tcp_mem[3];
221extern int sysctl_tcp_wmem[3];
222extern int sysctl_tcp_rmem[3];
223extern int sysctl_tcp_app_win;
224extern int sysctl_tcp_adv_win_scale;
225extern int sysctl_tcp_tw_reuse;
226extern int sysctl_tcp_frto;
227extern int sysctl_tcp_frto_response;
228extern int sysctl_tcp_low_latency;
229extern int sysctl_tcp_dma_copybreak;
230extern int sysctl_tcp_nometrics_save;
231extern int sysctl_tcp_moderate_rcvbuf;
232extern int sysctl_tcp_tso_win_divisor;
233extern int sysctl_tcp_abc;
234extern int sysctl_tcp_mtu_probing;
235extern int sysctl_tcp_base_mss;
236extern int sysctl_tcp_workaround_signed_windows;
237extern int sysctl_tcp_slow_start_after_idle;
238extern int sysctl_tcp_max_ssthresh;
239
240extern atomic_t tcp_memory_allocated;
241extern atomic_t tcp_sockets_allocated;
242extern int tcp_memory_pressure;
243
244/*
245 * The next routines deal with comparing 32 bit unsigned ints
246 * and worry about wraparound (automatic with unsigned arithmetic).
247 */
248
249static inline int before(__u32 seq1, __u32 seq2)
250{
251 return (__s32)(seq1-seq2) < 0;
252}
253#define after(seq2, seq1) before(seq1, seq2)
254
255/* is s2<=s1<=s3 ? */
256static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
257{
258 return seq3 - seq2 >= seq1 - seq2;
259}
260
261static inline int tcp_too_many_orphans(struct sock *sk, int num)
262{
263 return (num > sysctl_tcp_max_orphans) ||
264 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
265 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
266}
267
268extern struct proto tcp_prot;
269
270#define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
271#define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field)
272#define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
273#define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
274
275extern void tcp_v4_err(struct sk_buff *skb, u32);
276
277extern void tcp_shutdown (struct sock *sk, int how);
278
279extern int tcp_v4_rcv(struct sk_buff *skb);
280
281extern int tcp_v4_remember_stamp(struct sock *sk);
282
283extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
284
285extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock,
286 struct msghdr *msg, size_t size);
287extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
288
289extern int tcp_ioctl(struct sock *sk,
290 int cmd,
291 unsigned long arg);
292
293extern int tcp_rcv_state_process(struct sock *sk,
294 struct sk_buff *skb,
295 struct tcphdr *th,
296 unsigned len);
297
298extern int tcp_rcv_established(struct sock *sk,
299 struct sk_buff *skb,
300 struct tcphdr *th,
301 unsigned len);
302
303extern void tcp_rcv_space_adjust(struct sock *sk);
304
305extern void tcp_cleanup_rbuf(struct sock *sk, int copied);
306
307extern int tcp_twsk_unique(struct sock *sk,
308 struct sock *sktw, void *twp);
309
310extern void tcp_twsk_destructor(struct sock *sk);
311
312extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
313 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
314
315static inline void tcp_dec_quickack_mode(struct sock *sk,
316 const unsigned int pkts)
317{
318 struct inet_connection_sock *icsk = inet_csk(sk);
319
320 if (icsk->icsk_ack.quick) {
321 if (pkts >= icsk->icsk_ack.quick) {
322 icsk->icsk_ack.quick = 0;
323 /* Leaving quickack mode we deflate ATO. */
324 icsk->icsk_ack.ato = TCP_ATO_MIN;
325 } else
326 icsk->icsk_ack.quick -= pkts;
327 }
328}
329
330extern void tcp_enter_quickack_mode(struct sock *sk);
331
332static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
333{
334 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
335}
336
337#define TCP_ECN_OK 1
338#define TCP_ECN_QUEUE_CWR 2
339#define TCP_ECN_DEMAND_CWR 4
340
341static __inline__ void
342TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
343{
344 if (sysctl_tcp_ecn && th->ece && th->cwr)
345 inet_rsk(req)->ecn_ok = 1;
346}
347
348enum tcp_tw_status
349{
350 TCP_TW_SUCCESS = 0,
351 TCP_TW_RST = 1,
352 TCP_TW_ACK = 2,
353 TCP_TW_SYN = 3
354};
355
356
357extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw,
358 struct sk_buff *skb,
359 const struct tcphdr *th);
360
361extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
362 struct request_sock *req,
363 struct request_sock **prev);
364extern int tcp_child_process(struct sock *parent,
365 struct sock *child,
366 struct sk_buff *skb);
367extern int tcp_use_frto(struct sock *sk);
368extern void tcp_enter_frto(struct sock *sk);
369extern void tcp_enter_loss(struct sock *sk, int how);
370extern void tcp_clear_retrans(struct tcp_sock *tp);
371extern void tcp_update_metrics(struct sock *sk);
372
373extern void tcp_close(struct sock *sk,
374 long timeout);
375extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
376
377extern int tcp_getsockopt(struct sock *sk, int level,
378 int optname,
379 char __user *optval,
380 int __user *optlen);
381extern int tcp_setsockopt(struct sock *sk, int level,
382 int optname, char __user *optval,
383 int optlen);
384extern int compat_tcp_getsockopt(struct sock *sk,
385 int level, int optname,
386 char __user *optval, int __user *optlen);
387extern int compat_tcp_setsockopt(struct sock *sk,
388 int level, int optname,
389 char __user *optval, int optlen);
390extern void tcp_set_keepalive(struct sock *sk, int val);
391extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
392 struct msghdr *msg,
393 size_t len, int nonblock,
394 int flags, int *addr_len);
395
396extern void tcp_parse_options(struct sk_buff *skb,
397 struct tcp_options_received *opt_rx,
398 int estab);
399
400extern u8 *tcp_parse_md5sig_option(struct tcphdr *th);
401
402/*
403 * TCP v4 functions exported for the inet6 API
404 */
405
406extern void tcp_v4_send_check(struct sock *sk, int len,
407 struct sk_buff *skb);
408
409extern int tcp_v4_conn_request(struct sock *sk,
410 struct sk_buff *skb);
411
412extern struct sock * tcp_create_openreq_child(struct sock *sk,
413 struct request_sock *req,
414 struct sk_buff *skb);
415
416extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
417 struct sk_buff *skb,
418 struct request_sock *req,
419 struct dst_entry *dst);
420
421extern int tcp_v4_do_rcv(struct sock *sk,
422 struct sk_buff *skb);
423
424extern int tcp_v4_connect(struct sock *sk,
425 struct sockaddr *uaddr,
426 int addr_len);
427
428extern int tcp_connect(struct sock *sk);
429
430extern struct sk_buff * tcp_make_synack(struct sock *sk,
431 struct dst_entry *dst,
432 struct request_sock *req);
433
434extern int tcp_disconnect(struct sock *sk, int flags);
435
436
437/* From syncookies.c */
438extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
439extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
440 struct ip_options *opt);
441extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
442 __u16 *mss);
443
444extern __u32 cookie_init_timestamp(struct request_sock *req);
445extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt);
446
447/* From net/ipv6/syncookies.c */
448extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
449extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
450 __u16 *mss);
451
452/* tcp_output.c */
453
454extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
455 int nonagle);
456extern int tcp_may_send_now(struct sock *sk);
457extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
458extern void tcp_xmit_retransmit_queue(struct sock *);
459extern void tcp_simple_retransmit(struct sock *);
460extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
461extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int);
462
463extern void tcp_send_probe0(struct sock *);
464extern void tcp_send_partial(struct sock *);
465extern int tcp_write_wakeup(struct sock *);
466extern void tcp_send_fin(struct sock *sk);
467extern void tcp_send_active_reset(struct sock *sk, gfp_t priority);
468extern int tcp_send_synack(struct sock *);
469extern void tcp_push_one(struct sock *, unsigned int mss_now);
470extern void tcp_send_ack(struct sock *sk);
471extern void tcp_send_delayed_ack(struct sock *sk);
472
473/* tcp_input.c */
474extern void tcp_cwnd_application_limited(struct sock *sk);
475extern void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp,
476 struct sk_buff *skb);
477
478/* tcp_timer.c */
479extern void tcp_init_xmit_timers(struct sock *);
480static inline void tcp_clear_xmit_timers(struct sock *sk)
481{
482 inet_csk_clear_xmit_timers(sk);
483}
484
485extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
486extern unsigned int tcp_current_mss(struct sock *sk, int large);
487
488/* tcp.c */
489extern void tcp_get_info(struct sock *, struct tcp_info *);
490
491/* Read 'sendfile()'-style from a TCP socket */
492typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
493 unsigned int, size_t);
494extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
495 sk_read_actor_t recv_actor);
496
497extern void tcp_initialize_rcv_mss(struct sock *sk);
498
499extern int tcp_mtu_to_mss(struct sock *sk, int pmtu);
500extern int tcp_mss_to_mtu(struct sock *sk, int mss);
501extern void tcp_mtup_init(struct sock *sk);
502
503static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
504{
505 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
506 ntohl(TCP_FLAG_ACK) |
507 snd_wnd);
508}
509
510static inline void tcp_fast_path_on(struct tcp_sock *tp)
511{
512 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
513}
514
515static inline void tcp_fast_path_check(struct sock *sk)
516{
517 struct tcp_sock *tp = tcp_sk(sk);
518
519 if (skb_queue_empty(&tp->out_of_order_queue) &&
520 tp->rcv_wnd &&
521 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
522 !tp->urg_data)
523 tcp_fast_path_on(tp);
524}
525
526/* Compute the actual receive window we are currently advertising.
527 * Rcv_nxt can be after the window if our peer push more data
528 * than the offered window.
529 */
530static inline u32 tcp_receive_window(const struct tcp_sock *tp)
531{
532 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
533
534 if (win < 0)
535 win = 0;
536 return (u32) win;
537}
538
539/* Choose a new window, without checks for shrinking, and without
540 * scaling applied to the result. The caller does these things
541 * if necessary. This is a "raw" window selection.
542 */
543extern u32 __tcp_select_window(struct sock *sk);
544
545/* TCP timestamps are only 32-bits, this causes a slight
546 * complication on 64-bit systems since we store a snapshot
547 * of jiffies in the buffer control blocks below. We decided
548 * to use only the low 32-bits of jiffies and hide the ugly
549 * casts with the following macro.
550 */
551#define tcp_time_stamp ((__u32)(jiffies))
552
553/* This is what the send packet queuing engine uses to pass
554 * TCP per-packet control information to the transmission
555 * code. We also store the host-order sequence numbers in
556 * here too. This is 36 bytes on 32-bit architectures,
557 * 40 bytes on 64-bit machines, if this grows please adjust
558 * skbuff.h:skbuff->cb[xxx] size appropriately.
559 */
560struct tcp_skb_cb {
561 union {
562 struct inet_skb_parm h4;
563#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
564 struct inet6_skb_parm h6;
565#endif
566 } header; /* For incoming frames */
567 __u32 seq; /* Starting sequence number */
568 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
569 __u32 when; /* used to compute rtt's */
570 __u8 flags; /* TCP header flags. */
571
572 /* NOTE: These must match up to the flags byte in a
573 * real TCP header.
574 */
575#define TCPCB_FLAG_FIN 0x01
576#define TCPCB_FLAG_SYN 0x02
577#define TCPCB_FLAG_RST 0x04
578#define TCPCB_FLAG_PSH 0x08
579#define TCPCB_FLAG_ACK 0x10
580#define TCPCB_FLAG_URG 0x20
581#define TCPCB_FLAG_ECE 0x40
582#define TCPCB_FLAG_CWR 0x80
583
584 __u8 sacked; /* State flags for SACK/FACK. */
585#define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
586#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
587#define TCPCB_LOST 0x04 /* SKB is lost */
588#define TCPCB_TAGBITS 0x07 /* All tag bits */
589
590#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
591#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
592
593 __u16 urg_ptr; /* Valid w/URG flags is set. */
594 __u32 ack_seq; /* Sequence number ACK'd */
595};
596
597#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
598
599/* Due to TSO, an SKB can be composed of multiple actual
600 * packets. To keep these tracked properly, we use this.
601 */
602static inline int tcp_skb_pcount(const struct sk_buff *skb)
603{
604 return skb_shinfo(skb)->gso_segs;
605}
606
607/* This is valid iff tcp_skb_pcount() > 1. */
608static inline int tcp_skb_mss(const struct sk_buff *skb)
609{
610 return skb_shinfo(skb)->gso_size;
611}
612
613static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
614{
615 if (*count) {
616 *count -= decr;
617 if ((int)*count < 0)
618 *count = 0;
619 }
620}
621
622static inline void tcp_dec_pcount_approx(__u32 *count,
623 const struct sk_buff *skb)
624{
625 tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
626}
627
628/* Events passed to congestion control interface */
629enum tcp_ca_event {
630 CA_EVENT_TX_START, /* first transmit when no packets in flight */
631 CA_EVENT_CWND_RESTART, /* congestion window restart */
632 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
633 CA_EVENT_FRTO, /* fast recovery timeout */
634 CA_EVENT_LOSS, /* loss timeout */
635 CA_EVENT_FAST_ACK, /* in sequence ack */
636 CA_EVENT_SLOW_ACK, /* other ack */
637};
638
639/*
640 * Interface for adding new TCP congestion control handlers
641 */
642#define TCP_CA_NAME_MAX 16
643#define TCP_CA_MAX 128
644#define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX)
645
646#define TCP_CONG_NON_RESTRICTED 0x1
647#define TCP_CONG_RTT_STAMP 0x2
648
649struct tcp_congestion_ops {
650 struct list_head list;
651 unsigned long flags;
652
653 /* initialize private data (optional) */
654 void (*init)(struct sock *sk);
655 /* cleanup private data (optional) */
656 void (*release)(struct sock *sk);
657
658 /* return slow start threshold (required) */
659 u32 (*ssthresh)(struct sock *sk);
660 /* lower bound for congestion window (optional) */
661 u32 (*min_cwnd)(const struct sock *sk);
662 /* do new cwnd calculation (required) */
663 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight);
664 /* call before changing ca_state (optional) */
665 void (*set_state)(struct sock *sk, u8 new_state);
666 /* call when cwnd event occurs (optional) */
667 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);
668 /* new value of cwnd after loss (optional) */
669 u32 (*undo_cwnd)(struct sock *sk);
670 /* hook for packet ack accounting (optional) */
671 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
672 /* get info for inet_diag (optional) */
673 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
674
675 char name[TCP_CA_NAME_MAX];
676 struct module *owner;
677};
678
679extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
680extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
681
682extern void tcp_init_congestion_control(struct sock *sk);
683extern void tcp_cleanup_congestion_control(struct sock *sk);
684extern int tcp_set_default_congestion_control(const char *name);
685extern void tcp_get_default_congestion_control(char *name);
686extern void tcp_get_available_congestion_control(char *buf, size_t len);
687extern void tcp_get_allowed_congestion_control(char *buf, size_t len);
688extern int tcp_set_allowed_congestion_control(char *allowed);
689extern int tcp_set_congestion_control(struct sock *sk, const char *name);
690extern void tcp_slow_start(struct tcp_sock *tp);
691
692extern struct tcp_congestion_ops tcp_init_congestion_ops;
693extern u32 tcp_reno_ssthresh(struct sock *sk);
694extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight);
695extern u32 tcp_reno_min_cwnd(const struct sock *sk);
696extern struct tcp_congestion_ops tcp_reno;
697
698static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
699{
700 struct inet_connection_sock *icsk = inet_csk(sk);
701
702 if (icsk->icsk_ca_ops->set_state)
703 icsk->icsk_ca_ops->set_state(sk, ca_state);
704 icsk->icsk_ca_state = ca_state;
705}
706
707static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
708{
709 const struct inet_connection_sock *icsk = inet_csk(sk);
710
711 if (icsk->icsk_ca_ops->cwnd_event)
712 icsk->icsk_ca_ops->cwnd_event(sk, event);
713}
714
715/* These functions determine how the current flow behaves in respect of SACK
716 * handling. SACK is negotiated with the peer, and therefore it can vary
717 * between different flows.
718 *
719 * tcp_is_sack - SACK enabled
720 * tcp_is_reno - No SACK
721 * tcp_is_fack - FACK enabled, implies SACK enabled
722 */
723static inline int tcp_is_sack(const struct tcp_sock *tp)
724{
725 return tp->rx_opt.sack_ok;
726}
727
728static inline int tcp_is_reno(const struct tcp_sock *tp)
729{
730 return !tcp_is_sack(tp);
731}
732
733static inline int tcp_is_fack(const struct tcp_sock *tp)
734{
735 return tp->rx_opt.sack_ok & 2;
736}
737
738static inline void tcp_enable_fack(struct tcp_sock *tp)
739{
740 tp->rx_opt.sack_ok |= 2;
741}
742
743static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
744{
745 return tp->sacked_out + tp->lost_out;
746}
747
748/* This determines how many packets are "in the network" to the best
749 * of our knowledge. In many cases it is conservative, but where
750 * detailed information is available from the receiver (via SACK
751 * blocks etc.) we can make more aggressive calculations.
752 *
753 * Use this for decisions involving congestion control, use just
754 * tp->packets_out to determine if the send queue is empty or not.
755 *
756 * Read this equation as:
757 *
758 * "Packets sent once on transmission queue" MINUS
759 * "Packets left network, but not honestly ACKed yet" PLUS
760 * "Packets fast retransmitted"
761 */
762static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
763{
764 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
765}
766
767extern int tcp_limit_reno_sacked(struct tcp_sock *tp);
768
769/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
770 * The exception is rate halving phase, when cwnd is decreasing towards
771 * ssthresh.
772 */
773static inline __u32 tcp_current_ssthresh(const struct sock *sk)
774{
775 const struct tcp_sock *tp = tcp_sk(sk);
776 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery))
777 return tp->snd_ssthresh;
778 else
779 return max(tp->snd_ssthresh,
780 ((tp->snd_cwnd >> 1) +
781 (tp->snd_cwnd >> 2)));
782}
783
784/* Use define here intentionally to get WARN_ON location shown at the caller */
785#define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
786
787extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
788extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
789
790/* Slow start with delack produces 3 packets of burst, so that
791 * it is safe "de facto". This will be the default - same as
792 * the default reordering threshold - but if reordering increases,
793 * we must be able to allow cwnd to burst at least this much in order
794 * to not pull it back when holes are filled.
795 */
796static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
797{
798 return tp->reordering;
799}
800
801/* Returns end sequence number of the receiver's advertised window */
802static inline u32 tcp_wnd_end(const struct tcp_sock *tp)
803{
804 return tp->snd_una + tp->snd_wnd;
805}
806extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
807
808static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
809 const struct sk_buff *skb)
810{
811 if (skb->len < mss)
812 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
813}
814
815static inline void tcp_check_probe_timer(struct sock *sk)
816{
817 struct tcp_sock *tp = tcp_sk(sk);
818 const struct inet_connection_sock *icsk = inet_csk(sk);
819
820 if (!tp->packets_out && !icsk->icsk_pending)
821 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
822 icsk->icsk_rto, TCP_RTO_MAX);
823}
824
825static inline void tcp_push_pending_frames(struct sock *sk)
826{
827 struct tcp_sock *tp = tcp_sk(sk);
828
829 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle);
830}
831
832static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
833{
834 tp->snd_wl1 = seq;
835}
836
837static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
838{
839 tp->snd_wl1 = seq;
840}
841
842/*
843 * Calculate(/check) TCP checksum
844 */
845static inline __sum16 tcp_v4_check(int len, __be32 saddr,
846 __be32 daddr, __wsum base)
847{
848 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
849}
850
851static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb)
852{
853 return __skb_checksum_complete(skb);
854}
855
856static inline int tcp_checksum_complete(struct sk_buff *skb)
857{
858 return !skb_csum_unnecessary(skb) &&
859 __tcp_checksum_complete(skb);
860}
861
862/* Prequeue for VJ style copy to user, combined with checksumming. */
863
864static inline void tcp_prequeue_init(struct tcp_sock *tp)
865{
866 tp->ucopy.task = NULL;
867 tp->ucopy.len = 0;
868 tp->ucopy.memory = 0;
869 skb_queue_head_init(&tp->ucopy.prequeue);
870#ifdef CONFIG_NET_DMA
871 tp->ucopy.dma_chan = NULL;
872 tp->ucopy.wakeup = 0;
873 tp->ucopy.pinned_list = NULL;
874 tp->ucopy.dma_cookie = 0;
875#endif
876}
877
878/* Packet is added to VJ-style prequeue for processing in process
879 * context, if a reader task is waiting. Apparently, this exciting
880 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
881 * failed somewhere. Latency? Burstiness? Well, at least now we will
882 * see, why it failed. 8)8) --ANK
883 *
884 * NOTE: is this not too big to inline?
885 */
886static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
887{
888 struct tcp_sock *tp = tcp_sk(sk);
889
890 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
891 __skb_queue_tail(&tp->ucopy.prequeue, skb);
892 tp->ucopy.memory += skb->truesize;
893 if (tp->ucopy.memory > sk->sk_rcvbuf) {
894 struct sk_buff *skb1;
895
896 BUG_ON(sock_owned_by_user(sk));
897
898 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
899 sk->sk_backlog_rcv(sk, skb1);
900 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPREQUEUEDROPPED);
901 }
902
903 tp->ucopy.memory = 0;
904 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
905 wake_up_interruptible(sk->sk_sleep);
906 if (!inet_csk_ack_scheduled(sk))
907 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
908 (3 * TCP_RTO_MIN) / 4,
909 TCP_RTO_MAX);
910 }
911 return 1;
912 }
913 return 0;
914}
915
916
917#undef STATE_TRACE
918
919#ifdef STATE_TRACE
920static const char *statename[]={
921 "Unused","Established","Syn Sent","Syn Recv",
922 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
923 "Close Wait","Last ACK","Listen","Closing"
924};
925#endif
926extern void tcp_set_state(struct sock *sk, int state);
927
928extern void tcp_done(struct sock *sk);
929
930static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
931{
932 rx_opt->dsack = 0;
933 rx_opt->eff_sacks = 0;
934 rx_opt->num_sacks = 0;
935}
936
937/* Determine a window scaling and initial window to offer. */
938extern void tcp_select_initial_window(int __space, __u32 mss,
939 __u32 *rcv_wnd, __u32 *window_clamp,
940 int wscale_ok, __u8 *rcv_wscale);
941
942static inline int tcp_win_from_space(int space)
943{
944 return sysctl_tcp_adv_win_scale<=0 ?
945 (space>>(-sysctl_tcp_adv_win_scale)) :
946 space - (space>>sysctl_tcp_adv_win_scale);
947}
948
949/* Note: caller must be prepared to deal with negative returns */
950static inline int tcp_space(const struct sock *sk)
951{
952 return tcp_win_from_space(sk->sk_rcvbuf -
953 atomic_read(&sk->sk_rmem_alloc));
954}
955
956static inline int tcp_full_space(const struct sock *sk)
957{
958 return tcp_win_from_space(sk->sk_rcvbuf);
959}
960
961static inline void tcp_openreq_init(struct request_sock *req,
962 struct tcp_options_received *rx_opt,
963 struct sk_buff *skb)
964{
965 struct inet_request_sock *ireq = inet_rsk(req);
966
967 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
968 req->cookie_ts = 0;
969 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
970 req->mss = rx_opt->mss_clamp;
971 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
972 ireq->tstamp_ok = rx_opt->tstamp_ok;
973 ireq->sack_ok = rx_opt->sack_ok;
974 ireq->snd_wscale = rx_opt->snd_wscale;
975 ireq->wscale_ok = rx_opt->wscale_ok;
976 ireq->acked = 0;
977 ireq->ecn_ok = 0;
978 ireq->rmt_port = tcp_hdr(skb)->source;
979}
980
981extern void tcp_enter_memory_pressure(struct sock *sk);
982
983static inline int keepalive_intvl_when(const struct tcp_sock *tp)
984{
985 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
986}
987
988static inline int keepalive_time_when(const struct tcp_sock *tp)
989{
990 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
991}
992
993static inline int tcp_fin_time(const struct sock *sk)
994{
995 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;
996 const int rto = inet_csk(sk)->icsk_rto;
997
998 if (fin_timeout < (rto << 2) - (rto >> 1))
999 fin_timeout = (rto << 2) - (rto >> 1);
1000
1001 return fin_timeout;
1002}
1003
1004static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1005{
1006 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1007 return 0;
1008 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1009 return 0;
1010
1011 /* RST segments are not recommended to carry timestamp,
1012 and, if they do, it is recommended to ignore PAWS because
1013 "their cleanup function should take precedence over timestamps."
1014 Certainly, it is mistake. It is necessary to understand the reasons
1015 of this constraint to relax it: if peer reboots, clock may go
1016 out-of-sync and half-open connections will not be reset.
1017 Actually, the problem would be not existing if all
1018 the implementations followed draft about maintaining clock
1019 via reboots. Linux-2.2 DOES NOT!
1020
1021 However, we can relax time bounds for RST segments to MSL.
1022 */
1023 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1024 return 0;
1025 return 1;
1026}
1027
1028#define TCP_CHECK_TIMER(sk) do { } while (0)
1029
1030static inline void tcp_mib_init(struct net *net)
1031{
1032 /* See RFC 2012 */
1033 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
1034 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1035 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1036 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
1037}
1038
1039/* from STCP */
1040static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
1041{
1042 tp->lost_skb_hint = NULL;
1043 tp->scoreboard_skb_hint = NULL;
1044 tp->retransmit_skb_hint = NULL;
1045}
1046
1047/* MD5 Signature */
1048struct crypto_hash;
1049
1050/* - key database */
1051struct tcp_md5sig_key {
1052 u8 *key;
1053 u8 keylen;
1054};
1055
1056struct tcp4_md5sig_key {
1057 struct tcp_md5sig_key base;
1058 __be32 addr;
1059};
1060
1061struct tcp6_md5sig_key {
1062 struct tcp_md5sig_key base;
1063#if 0
1064 u32 scope_id; /* XXX */
1065#endif
1066 struct in6_addr addr;
1067};
1068
1069/* - sock block */
1070struct tcp_md5sig_info {
1071 struct tcp4_md5sig_key *keys4;
1072#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1073 struct tcp6_md5sig_key *keys6;
1074 u32 entries6;
1075 u32 alloced6;
1076#endif
1077 u32 entries4;
1078 u32 alloced4;
1079};
1080
1081/* - pseudo header */
1082struct tcp4_pseudohdr {
1083 __be32 saddr;
1084 __be32 daddr;
1085 __u8 pad;
1086 __u8 protocol;
1087 __be16 len;
1088};
1089
1090struct tcp6_pseudohdr {
1091 struct in6_addr saddr;
1092 struct in6_addr daddr;
1093 __be32 len;
1094 __be32 protocol; /* including padding */
1095};
1096
1097union tcp_md5sum_block {
1098 struct tcp4_pseudohdr ip4;
1099#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
1100 struct tcp6_pseudohdr ip6;
1101#endif
1102};
1103
1104/* - pool: digest algorithm, hash description and scratch buffer */
1105struct tcp_md5sig_pool {
1106 struct hash_desc md5_desc;
1107 union tcp_md5sum_block md5_blk;
1108};
1109
1110#define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */
1111
1112/* - functions */
1113extern int tcp_v4_md5_hash_skb(char *md5_hash,
1114 struct tcp_md5sig_key *key,
1115 struct sock *sk,
1116 struct request_sock *req,
1117 struct sk_buff *skb);
1118
1119extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
1120 struct sock *addr_sk);
1121
1122extern int tcp_v4_md5_do_add(struct sock *sk,
1123 __be32 addr,
1124 u8 *newkey,
1125 u8 newkeylen);
1126
1127extern int tcp_v4_md5_do_del(struct sock *sk,
1128 __be32 addr);
1129
1130#ifdef CONFIG_TCP_MD5SIG
1131#define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \
1132 &(struct tcp_md5sig_key) { \
1133 .key = (twsk)->tw_md5_key, \
1134 .keylen = (twsk)->tw_md5_keylen, \
1135 } : NULL)
1136#else
1137#define tcp_twsk_md5_key(twsk) NULL
1138#endif
1139
1140extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
1141extern void tcp_free_md5sig_pool(void);
1142
1143extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);
1144extern void __tcp_put_md5sig_pool(void);
1145extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *);
1146extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *,
1147 unsigned header_len);
1148extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
1149 struct tcp_md5sig_key *key);
1150
1151static inline
1152struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
1153{
1154 int cpu = get_cpu();
1155 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu);
1156 if (!ret)
1157 put_cpu();
1158 return ret;
1159}
1160
1161static inline void tcp_put_md5sig_pool(void)
1162{
1163 __tcp_put_md5sig_pool();
1164 put_cpu();
1165}
1166
1167/* write queue abstraction */
1168static inline void tcp_write_queue_purge(struct sock *sk)
1169{
1170 struct sk_buff *skb;
1171
1172 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
1173 sk_wmem_free_skb(sk, skb);
1174 sk_mem_reclaim(sk);
1175}
1176
1177static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
1178{
1179 struct sk_buff *skb = sk->sk_write_queue.next;
1180 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1181 return NULL;
1182 return skb;
1183}
1184
1185static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk)
1186{
1187 struct sk_buff *skb = sk->sk_write_queue.prev;
1188 if (skb == (struct sk_buff *) &sk->sk_write_queue)
1189 return NULL;
1190 return skb;
1191}
1192
1193static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb)
1194{
1195 return skb->next;
1196}
1197
1198#define tcp_for_write_queue(skb, sk) \
1199 for (skb = (sk)->sk_write_queue.next; \
1200 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1201 skb = skb->next)
1202
1203#define tcp_for_write_queue_from(skb, sk) \
1204 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\
1205 skb = skb->next)
1206
1207#define tcp_for_write_queue_from_safe(skb, tmp, sk) \
1208 for (tmp = skb->next; \
1209 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \
1210 skb = tmp, tmp = skb->next)
1211
1212static inline struct sk_buff *tcp_send_head(struct sock *sk)
1213{
1214 return sk->sk_send_head;
1215}
1216
1217static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb)
1218{
1219 sk->sk_send_head = skb->next;
1220 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue)
1221 sk->sk_send_head = NULL;
1222}
1223
1224static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked)
1225{
1226 if (sk->sk_send_head == skb_unlinked)
1227 sk->sk_send_head = NULL;
1228}
1229
1230static inline void tcp_init_send_head(struct sock *sk)
1231{
1232 sk->sk_send_head = NULL;
1233}
1234
1235static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1236{
1237 __skb_queue_tail(&sk->sk_write_queue, skb);
1238}
1239
1240static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb)
1241{
1242 __tcp_add_write_queue_tail(sk, skb);
1243
1244 /* Queue it, remembering where we must start sending. */
1245 if (sk->sk_send_head == NULL) {
1246 sk->sk_send_head = skb;
1247
1248 if (tcp_sk(sk)->highest_sack == NULL)
1249 tcp_sk(sk)->highest_sack = skb;
1250 }
1251}
1252
1253static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb)
1254{
1255 __skb_queue_head(&sk->sk_write_queue, skb);
1256}
1257
1258/* Insert buff after skb on the write queue of sk. */
1259static inline void tcp_insert_write_queue_after(struct sk_buff *skb,
1260 struct sk_buff *buff,
1261 struct sock *sk)
1262{
1263 __skb_queue_after(&sk->sk_write_queue, skb, buff);
1264}
1265
1266/* Insert skb between prev and next on the write queue of sk. */
1267static inline void tcp_insert_write_queue_before(struct sk_buff *new,
1268 struct sk_buff *skb,
1269 struct sock *sk)
1270{
1271 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue);
1272
1273 if (sk->sk_send_head == skb)
1274 sk->sk_send_head = new;
1275}
1276
1277static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
1278{
1279 __skb_unlink(skb, &sk->sk_write_queue);
1280}
1281
1282static inline int tcp_skb_is_last(const struct sock *sk,
1283 const struct sk_buff *skb)
1284{
1285 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1286}
1287
1288static inline int tcp_write_queue_empty(struct sock *sk)
1289{
1290 return skb_queue_empty(&sk->sk_write_queue);
1291}
1292
1293/* Start sequence of the highest skb with SACKed bit, valid only if
1294 * sacked > 0 or when the caller has ensured validity by itself.
1295 */
1296static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
1297{
1298 if (!tp->sacked_out)
1299 return tp->snd_una;
1300
1301 if (tp->highest_sack == NULL)
1302 return tp->snd_nxt;
1303
1304 return TCP_SKB_CB(tp->highest_sack)->seq;
1305}
1306
1307static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb)
1308{
1309 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL :
1310 tcp_write_queue_next(sk, skb);
1311}
1312
1313static inline struct sk_buff *tcp_highest_sack(struct sock *sk)
1314{
1315 return tcp_sk(sk)->highest_sack;
1316}
1317
1318static inline void tcp_highest_sack_reset(struct sock *sk)
1319{
1320 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk);
1321}
1322
1323/* Called when old skb is about to be deleted (to be combined with new skb) */
1324static inline void tcp_highest_sack_combine(struct sock *sk,
1325 struct sk_buff *old,
1326 struct sk_buff *new)
1327{
1328 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack))
1329 tcp_sk(sk)->highest_sack = new;
1330}
1331
1332/* /proc */
1333enum tcp_seq_states {
1334 TCP_SEQ_STATE_LISTENING,
1335 TCP_SEQ_STATE_OPENREQ,
1336 TCP_SEQ_STATE_ESTABLISHED,
1337 TCP_SEQ_STATE_TIME_WAIT,
1338};
1339
1340struct tcp_seq_afinfo {
1341 char *name;
1342 sa_family_t family;
1343 struct file_operations seq_fops;
1344 struct seq_operations seq_ops;
1345};
1346
1347struct tcp_iter_state {
1348 struct seq_net_private p;
1349 sa_family_t family;
1350 enum tcp_seq_states state;
1351 struct sock *syn_wait_sk;
1352 int bucket, sbucket, num, uid;
1353};
1354
1355extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo);
1356extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo);
1357
1358extern struct request_sock_ops tcp_request_sock_ops;
1359extern struct request_sock_ops tcp6_request_sock_ops;
1360
1361extern void tcp_v4_destroy_sock(struct sock *sk);
1362
1363extern int tcp_v4_gso_send_check(struct sk_buff *skb);
1364extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
1365
1366#ifdef CONFIG_PROC_FS
1367extern int tcp4_proc_init(void);
1368extern void tcp4_proc_exit(void);
1369#endif
1370
1371/* TCP af-specific functions */
1372struct tcp_sock_af_ops {
1373#ifdef CONFIG_TCP_MD5SIG
1374 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1375 struct sock *addr_sk);
1376 int (*calc_md5_hash) (char *location,
1377 struct tcp_md5sig_key *md5,
1378 struct sock *sk,
1379 struct request_sock *req,
1380 struct sk_buff *skb);
1381 int (*md5_add) (struct sock *sk,
1382 struct sock *addr_sk,
1383 u8 *newkey,
1384 u8 len);
1385 int (*md5_parse) (struct sock *sk,
1386 char __user *optval,
1387 int optlen);
1388#endif
1389};
1390
1391struct tcp_request_sock_ops {
1392#ifdef CONFIG_TCP_MD5SIG
1393 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk,
1394 struct request_sock *req);
1395#endif
1396};
1397
1398extern void tcp_v4_init(void);
1399extern void tcp_init(void);
1400
1401#endif /* _TCP_H */
Linux 6.x block layer and io_uring tree(s)