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[TCP]: Fix quick-ack decrementing with TSO.
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / net / tcp.h
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1da177e4
LT		 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 *
02c30a84 10 * Authors: Ross Biro
1da177e4
LT		 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/* Cancel timers, when they are not required. */
25#undef TCP_CLEAR_TIMERS
26
27#include <linux/config.h>
28#include <linux/list.h>
29#include <linux/tcp.h>
30#include <linux/slab.h>
31#include <linux/cache.h>
32#include <linux/percpu.h>
33#include <net/checksum.h>
2e6599cb 34#include <net/request_sock.h>
1da177e4
LT		 35#include <net/sock.h>
36#include <net/snmp.h>
37#include <net/ip.h>
38#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
39#include <linux/ipv6.h>
40#endif
41#include <linux/seq_file.h>
42
43/* This is for all connections with a full identity, no wildcards.
44 * New scheme, half the table is for TIME_WAIT, the other half is
45 * for the rest. I'll experiment with dynamic table growth later.
46 */
47struct tcp_ehash_bucket {
48 rwlock_t lock;
49 struct hlist_head chain;
50} __attribute__((__aligned__(8)));
51
52/* This is for listening sockets, thus all sockets which possess wildcards. */
53#define TCP_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */
54
55/* There are a few simple rules, which allow for local port reuse by
56 * an application. In essence:
57 *
58 * 1) Sockets bound to different interfaces may share a local port.
59 * Failing that, goto test 2.
60 * 2) If all sockets have sk->sk_reuse set, and none of them are in
61 * TCP_LISTEN state, the port may be shared.
62 * Failing that, goto test 3.
63 * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local
64 * address, and none of them are the same, the port may be
65 * shared.
66 * Failing this, the port cannot be shared.
67 *
68 * The interesting point, is test #2. This is what an FTP server does
69 * all day. To optimize this case we use a specific flag bit defined
70 * below. As we add sockets to a bind bucket list, we perform a
71 * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN))
72 * As long as all sockets added to a bind bucket pass this test,
73 * the flag bit will be set.
74 * The resulting situation is that tcp_v[46]_verify_bind() can just check
75 * for this flag bit, if it is set and the socket trying to bind has
76 * sk->sk_reuse set, we don't even have to walk the owners list at all,
77 * we return that it is ok to bind this socket to the requested local port.
78 *
79 * Sounds like a lot of work, but it is worth it. In a more naive
80 * implementation (ie. current FreeBSD etc.) the entire list of ports
81 * must be walked for each data port opened by an ftp server. Needless
82 * to say, this does not scale at all. With a couple thousand FTP
83 * users logged onto your box, isn't it nice to know that new data
84 * ports are created in O(1) time? I thought so. ;-) -DaveM
85 */
86struct tcp_bind_bucket {
87 unsigned short port;
88 signed short fastreuse;
89 struct hlist_node node;
90 struct hlist_head owners;
91};
92
93#define tb_for_each(tb, node, head) hlist_for_each_entry(tb, node, head, node)
94
95struct tcp_bind_hashbucket {
96 spinlock_t lock;
97 struct hlist_head chain;
98};
99
100static inline struct tcp_bind_bucket *__tb_head(struct tcp_bind_hashbucket *head)
101{
102 return hlist_entry(head->chain.first, struct tcp_bind_bucket, node);
103}
104
105static inline struct tcp_bind_bucket *tb_head(struct tcp_bind_hashbucket *head)
106{
107 return hlist_empty(&head->chain) ? NULL : __tb_head(head);
108}
109
110extern struct tcp_hashinfo {
111 /* This is for sockets with full identity only. Sockets here will
112 * always be without wildcards and will have the following invariant:
113 *
114 * TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE
115 *
116 * First half of the table is for sockets not in TIME_WAIT, second half
117 * is for TIME_WAIT sockets only.
118 */
119 struct tcp_ehash_bucket *__tcp_ehash;
120
121 /* Ok, let's try this, I give up, we do need a local binding
122 * TCP hash as well as the others for fast bind/connect.
123 */
124 struct tcp_bind_hashbucket *__tcp_bhash;
125
126 int __tcp_bhash_size;
127 int __tcp_ehash_size;
128
129 /* All sockets in TCP_LISTEN state will be in here. This is the only
130 * table where wildcard'd TCP sockets can exist. Hash function here
131 * is just local port number.
132 */
133 struct hlist_head __tcp_listening_hash[TCP_LHTABLE_SIZE];
134
135 /* All the above members are written once at bootup and
136 * never written again _or_ are predominantly read-access.
137 *
138 * Now align to a new cache line as all the following members
139 * are often dirty.
140 */
141 rwlock_t __tcp_lhash_lock ____cacheline_aligned;
142 atomic_t __tcp_lhash_users;
143 wait_queue_head_t __tcp_lhash_wait;
144 spinlock_t __tcp_portalloc_lock;
145} tcp_hashinfo;
146
147#define tcp_ehash (tcp_hashinfo.__tcp_ehash)
148#define tcp_bhash (tcp_hashinfo.__tcp_bhash)
149#define tcp_ehash_size (tcp_hashinfo.__tcp_ehash_size)
150#define tcp_bhash_size (tcp_hashinfo.__tcp_bhash_size)
151#define tcp_listening_hash (tcp_hashinfo.__tcp_listening_hash)
152#define tcp_lhash_lock (tcp_hashinfo.__tcp_lhash_lock)
153#define tcp_lhash_users (tcp_hashinfo.__tcp_lhash_users)
154#define tcp_lhash_wait (tcp_hashinfo.__tcp_lhash_wait)
155#define tcp_portalloc_lock (tcp_hashinfo.__tcp_portalloc_lock)
156
157extern kmem_cache_t *tcp_bucket_cachep;
158extern struct tcp_bind_bucket *tcp_bucket_create(struct tcp_bind_hashbucket *head,
159 unsigned short snum);
160extern void tcp_bucket_destroy(struct tcp_bind_bucket *tb);
161extern void tcp_bucket_unlock(struct sock *sk);
162extern int tcp_port_rover;
163
164/* These are AF independent. */
165static __inline__ int tcp_bhashfn(__u16 lport)
166{
167 return (lport & (tcp_bhash_size - 1));
168}
169
170extern void tcp_bind_hash(struct sock *sk, struct tcp_bind_bucket *tb,
171 unsigned short snum);
172
173#if (BITS_PER_LONG == 64)
174#define TCP_ADDRCMP_ALIGN_BYTES 8
175#else
176#define TCP_ADDRCMP_ALIGN_BYTES 4
177#endif
178
179/* This is a TIME_WAIT bucket. It works around the memory consumption
180 * problems of sockets in such a state on heavily loaded servers, but
181 * without violating the protocol specification.
182 */
183struct tcp_tw_bucket {
184 /*
185 * Now struct sock also uses sock_common, so please just
186 * don't add nothing before this first member (__tw_common) --acme
187 */
188 struct sock_common __tw_common;
189#define tw_family __tw_common.skc_family
190#define tw_state __tw_common.skc_state
191#define tw_reuse __tw_common.skc_reuse
192#define tw_bound_dev_if __tw_common.skc_bound_dev_if
193#define tw_node __tw_common.skc_node
194#define tw_bind_node __tw_common.skc_bind_node
195#define tw_refcnt __tw_common.skc_refcnt
196 volatile unsigned char tw_substate;
197 unsigned char tw_rcv_wscale;
198 __u16 tw_sport;
199 /* Socket demultiplex comparisons on incoming packets. */
200 /* these five are in inet_sock */
201 __u32 tw_daddr
202 __attribute__((aligned(TCP_ADDRCMP_ALIGN_BYTES)));
203 __u32 tw_rcv_saddr;
204 __u16 tw_dport;
205 __u16 tw_num;
206 /* And these are ours. */
207 int tw_hashent;
208 int tw_timeout;
209 __u32 tw_rcv_nxt;
210 __u32 tw_snd_nxt;
211 __u32 tw_rcv_wnd;
212 __u32 tw_ts_recent;
213 long tw_ts_recent_stamp;
214 unsigned long tw_ttd;
215 struct tcp_bind_bucket *tw_tb;
216 struct hlist_node tw_death_node;
217#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
218 struct in6_addr tw_v6_daddr;
219 struct in6_addr tw_v6_rcv_saddr;
220 int tw_v6_ipv6only;
221#endif
222};
223
224static __inline__ void tw_add_node(struct tcp_tw_bucket *tw,
225 struct hlist_head *list)
226{
227 hlist_add_head(&tw->tw_node, list);
228}
229
230static __inline__ void tw_add_bind_node(struct tcp_tw_bucket *tw,
231 struct hlist_head *list)
232{
233 hlist_add_head(&tw->tw_bind_node, list);
234}
235
236static inline int tw_dead_hashed(struct tcp_tw_bucket *tw)
237{
238 return tw->tw_death_node.pprev != NULL;
239}
240
241static __inline__ void tw_dead_node_init(struct tcp_tw_bucket *tw)
242{
243 tw->tw_death_node.pprev = NULL;
244}
245
246static __inline__ void __tw_del_dead_node(struct tcp_tw_bucket *tw)
247{
248 __hlist_del(&tw->tw_death_node);
249 tw_dead_node_init(tw);
250}
251
252static __inline__ int tw_del_dead_node(struct tcp_tw_bucket *tw)
253{
254 if (tw_dead_hashed(tw)) {
255 __tw_del_dead_node(tw);
256 return 1;
257 }
258 return 0;
259}
260
261#define tw_for_each(tw, node, head) \
262 hlist_for_each_entry(tw, node, head, tw_node)
263
264#define tw_for_each_inmate(tw, node, jail) \
265 hlist_for_each_entry(tw, node, jail, tw_death_node)
266
267#define tw_for_each_inmate_safe(tw, node, safe, jail) \
268 hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
269
270#define tcptw_sk(__sk) ((struct tcp_tw_bucket *)(__sk))
271
272static inline u32 tcp_v4_rcv_saddr(const struct sock *sk)
273{
274 return likely(sk->sk_state != TCP_TIME_WAIT) ?
275 inet_sk(sk)->rcv_saddr : tcptw_sk(sk)->tw_rcv_saddr;
276}
277
278#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
279static inline struct in6_addr *__tcp_v6_rcv_saddr(const struct sock *sk)
280{
281 return likely(sk->sk_state != TCP_TIME_WAIT) ?
282 &inet6_sk(sk)->rcv_saddr : &tcptw_sk(sk)->tw_v6_rcv_saddr;
283}
284
285static inline struct in6_addr *tcp_v6_rcv_saddr(const struct sock *sk)
286{
287 return sk->sk_family == AF_INET6 ? __tcp_v6_rcv_saddr(sk) : NULL;
288}
289
290#define tcptw_sk_ipv6only(__sk) (tcptw_sk(__sk)->tw_v6_ipv6only)
291
292static inline int tcp_v6_ipv6only(const struct sock *sk)
293{
294 return likely(sk->sk_state != TCP_TIME_WAIT) ?
295 ipv6_only_sock(sk) : tcptw_sk_ipv6only(sk);
296}
297#else
298# define __tcp_v6_rcv_saddr(__sk) NULL
299# define tcp_v6_rcv_saddr(__sk) NULL
300# define tcptw_sk_ipv6only(__sk) 0
301# define tcp_v6_ipv6only(__sk) 0
302#endif
303
304extern kmem_cache_t *tcp_timewait_cachep;
305
306static inline void tcp_tw_put(struct tcp_tw_bucket *tw)
307{
308 if (atomic_dec_and_test(&tw->tw_refcnt)) {
309#ifdef INET_REFCNT_DEBUG
310 printk(KERN_DEBUG "tw_bucket %p released\n", tw);
311#endif
312 kmem_cache_free(tcp_timewait_cachep, tw);
313 }
314}
315
316extern atomic_t tcp_orphan_count;
317extern int tcp_tw_count;
318extern void tcp_time_wait(struct sock *sk, int state, int timeo);
319extern void tcp_tw_deschedule(struct tcp_tw_bucket *tw);
320
321
322/* Socket demux engine toys. */
323#ifdef __BIG_ENDIAN
324#define TCP_COMBINED_PORTS(__sport, __dport) \
325 (((__u32)(__sport)<<16) | (__u32)(__dport))
326#else /* __LITTLE_ENDIAN */
327#define TCP_COMBINED_PORTS(__sport, __dport) \
328 (((__u32)(__dport)<<16) | (__u32)(__sport))
329#endif
330
331#if (BITS_PER_LONG == 64)
332#ifdef __BIG_ENDIAN
333#define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) \
334 __u64 __name = (((__u64)(__saddr))<<32)|((__u64)(__daddr));
335#else /* __LITTLE_ENDIAN */
336#define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) \
337 __u64 __name = (((__u64)(__daddr))<<32)|((__u64)(__saddr));
338#endif /* __BIG_ENDIAN */
339#define TCP_IPV4_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
340 (((*((__u64 *)&(inet_sk(__sk)->daddr)))== (__cookie)) && \
341 ((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \
342 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
343#define TCP_IPV4_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
344 (((*((__u64 *)&(tcptw_sk(__sk)->tw_daddr))) == (__cookie)) && \
345 ((*((__u32 *)&(tcptw_sk(__sk)->tw_dport))) == (__ports)) && \
346 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
347#else /* 32-bit arch */
348#define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr)
349#define TCP_IPV4_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
350 ((inet_sk(__sk)->daddr == (__saddr)) && \
351 (inet_sk(__sk)->rcv_saddr == (__daddr)) && \
352 ((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \
353 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
354#define TCP_IPV4_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
355 ((tcptw_sk(__sk)->tw_daddr == (__saddr)) && \
356 (tcptw_sk(__sk)->tw_rcv_saddr == (__daddr)) && \
357 ((*((__u32 *)&(tcptw_sk(__sk)->tw_dport))) == (__ports)) && \
358 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
359#endif /* 64-bit arch */
360
361#define TCP_IPV6_MATCH(__sk, __saddr, __daddr, __ports, __dif) \
362 (((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \
363 ((__sk)->sk_family == AF_INET6) && \
364 ipv6_addr_equal(&inet6_sk(__sk)->daddr, (__saddr)) && \
365 ipv6_addr_equal(&inet6_sk(__sk)->rcv_saddr, (__daddr)) && \
366 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
367
368/* These can have wildcards, don't try too hard. */
369static __inline__ int tcp_lhashfn(unsigned short num)
370{
371 return num & (TCP_LHTABLE_SIZE - 1);
372}
373
374static __inline__ int tcp_sk_listen_hashfn(struct sock *sk)
375{
376 return tcp_lhashfn(inet_sk(sk)->num);
377}
378
379#define MAX_TCP_HEADER (128 + MAX_HEADER)
380
381/*
382 * Never offer a window over 32767 without using window scaling. Some
383 * poor stacks do signed 16bit maths!
384 */
385#define MAX_TCP_WINDOW 32767U
386
387/* Minimal accepted MSS. It is (60+60+8) - (20+20). */
388#define TCP_MIN_MSS 88U
389
390/* Minimal RCV_MSS. */
391#define TCP_MIN_RCVMSS 536U
392
393/* After receiving this amount of duplicate ACKs fast retransmit starts. */
394#define TCP_FASTRETRANS_THRESH 3
395
396/* Maximal reordering. */
397#define TCP_MAX_REORDERING 127
398
399/* Maximal number of ACKs sent quickly to accelerate slow-start. */
400#define TCP_MAX_QUICKACKS 16U
401
402/* urg_data states */
403#define TCP_URG_VALID 0x0100
404#define TCP_URG_NOTYET 0x0200
405#define TCP_URG_READ 0x0400
406
407#define TCP_RETR1 3 /*
408 * This is how many retries it does before it
409 * tries to figure out if the gateway is
410 * down. Minimal RFC value is 3; it corresponds
411 * to ~3sec-8min depending on RTO.
412 */
413
414#define TCP_RETR2 15 /*
415 * This should take at least
416 * 90 minutes to time out.
417 * RFC1122 says that the limit is 100 sec.
418 * 15 is ~13-30min depending on RTO.
419 */
420
421#define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
422 * connection: ~180sec is RFC minumum */
423
424#define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
425 * connection: ~180sec is RFC minumum */
426
427
428#define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
429 * socket. 7 is ~50sec-16min.
430 */
431
432
433#define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
434 * state, about 60 seconds */
435#define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
436 /* BSD style FIN_WAIT2 deadlock breaker.
437 * It used to be 3min, new value is 60sec,
438 * to combine FIN-WAIT-2 timeout with
439 * TIME-WAIT timer.
440 */
441
442#define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
443#if HZ >= 100
444#define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
445#define TCP_ATO_MIN ((unsigned)(HZ/25))
446#else
447#define TCP_DELACK_MIN 4U
448#define TCP_ATO_MIN 4U
449#endif
450#define TCP_RTO_MAX ((unsigned)(120*HZ))
451#define TCP_RTO_MIN ((unsigned)(HZ/5))
452#define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
453
454#define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
455 * for local resources.
456 */
457
458#define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
459#define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
460#define TCP_KEEPALIVE_INTVL (75*HZ)
461
462#define MAX_TCP_KEEPIDLE 32767
463#define MAX_TCP_KEEPINTVL 32767
464#define MAX_TCP_KEEPCNT 127
465#define MAX_TCP_SYNCNT 127
466
467#define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
468#define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */
469
470#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
471#define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
472 * after this time. It should be equal
473 * (or greater than) TCP_TIMEWAIT_LEN
474 * to provide reliability equal to one
475 * provided by timewait state.
476 */
477#define TCP_PAWS_WINDOW 1 /* Replay window for per-host
478 * timestamps. It must be less than
479 * minimal timewait lifetime.
480 */
481
482#define TCP_TW_RECYCLE_SLOTS_LOG 5
483#define TCP_TW_RECYCLE_SLOTS (1<<TCP_TW_RECYCLE_SLOTS_LOG)
484
485/* If time > 4sec, it is "slow" path, no recycling is required,
486 so that we select tick to get range about 4 seconds.
487 */
488
489#if HZ <= 16 || HZ > 4096
490# error Unsupported: HZ <= 16 or HZ > 4096
491#elif HZ <= 32
492# define TCP_TW_RECYCLE_TICK (5+2-TCP_TW_RECYCLE_SLOTS_LOG)
493#elif HZ <= 64
494# define TCP_TW_RECYCLE_TICK (6+2-TCP_TW_RECYCLE_SLOTS_LOG)
495#elif HZ <= 128
496# define TCP_TW_RECYCLE_TICK (7+2-TCP_TW_RECYCLE_SLOTS_LOG)
497#elif HZ <= 256
498# define TCP_TW_RECYCLE_TICK (8+2-TCP_TW_RECYCLE_SLOTS_LOG)
499#elif HZ <= 512
500# define TCP_TW_RECYCLE_TICK (9+2-TCP_TW_RECYCLE_SLOTS_LOG)
501#elif HZ <= 1024
502# define TCP_TW_RECYCLE_TICK (10+2-TCP_TW_RECYCLE_SLOTS_LOG)
503#elif HZ <= 2048
504# define TCP_TW_RECYCLE_TICK (11+2-TCP_TW_RECYCLE_SLOTS_LOG)
505#else
506# define TCP_TW_RECYCLE_TICK (12+2-TCP_TW_RECYCLE_SLOTS_LOG)
507#endif
1da177e4
LT		 508/*
509 * TCP option
510 */
511
512#define TCPOPT_NOP 1 /* Padding */
513#define TCPOPT_EOL 0 /* End of options */
514#define TCPOPT_MSS 2 /* Segment size negotiating */
515#define TCPOPT_WINDOW 3 /* Window scaling */
516#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
517#define TCPOPT_SACK 5 /* SACK Block */
518#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
519
520/*
521 * TCP option lengths
522 */
523
524#define TCPOLEN_MSS 4
525#define TCPOLEN_WINDOW 3
526#define TCPOLEN_SACK_PERM 2
527#define TCPOLEN_TIMESTAMP 10
528
529/* But this is what stacks really send out. */
530#define TCPOLEN_TSTAMP_ALIGNED 12
531#define TCPOLEN_WSCALE_ALIGNED 4
532#define TCPOLEN_SACKPERM_ALIGNED 4
533#define TCPOLEN_SACK_BASE 2
534#define TCPOLEN_SACK_BASE_ALIGNED 4
535#define TCPOLEN_SACK_PERBLOCK 8
536
537#define TCP_TIME_RETRANS 1 /* Retransmit timer */
538#define TCP_TIME_DACK 2 /* Delayed ack timer */
539#define TCP_TIME_PROBE0 3 /* Zero window probe timer */
540#define TCP_TIME_KEEPOPEN 4 /* Keepalive timer */
541
542/* Flags in tp->nonagle */
543#define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
544#define TCP_NAGLE_CORK 2 /* Socket is corked */
545#define TCP_NAGLE_PUSH 4 /* Cork is overriden for already queued data */
546
547/* sysctl variables for tcp */
1da177e4
LT		 548extern int sysctl_tcp_timestamps;
549extern int sysctl_tcp_window_scaling;
550extern int sysctl_tcp_sack;
551extern int sysctl_tcp_fin_timeout;
552extern int sysctl_tcp_tw_recycle;
553extern int sysctl_tcp_keepalive_time;
554extern int sysctl_tcp_keepalive_probes;
555extern int sysctl_tcp_keepalive_intvl;
556extern int sysctl_tcp_syn_retries;
557extern int sysctl_tcp_synack_retries;
558extern int sysctl_tcp_retries1;
559extern int sysctl_tcp_retries2;
560extern int sysctl_tcp_orphan_retries;
561extern int sysctl_tcp_syncookies;
562extern int sysctl_tcp_retrans_collapse;
563extern int sysctl_tcp_stdurg;
564extern int sysctl_tcp_rfc1337;
565extern int sysctl_tcp_abort_on_overflow;
566extern int sysctl_tcp_max_orphans;
567extern int sysctl_tcp_max_tw_buckets;
568extern int sysctl_tcp_fack;
569extern int sysctl_tcp_reordering;
570extern int sysctl_tcp_ecn;
571extern int sysctl_tcp_dsack;
572extern int sysctl_tcp_mem[3];
573extern int sysctl_tcp_wmem[3];
574extern int sysctl_tcp_rmem[3];
575extern int sysctl_tcp_app_win;
576extern int sysctl_tcp_adv_win_scale;
577extern int sysctl_tcp_tw_reuse;
578extern int sysctl_tcp_frto;
579extern int sysctl_tcp_low_latency;
1da177e4 580extern int sysctl_tcp_nometrics_save;
1da177e4
LT		 581extern int sysctl_tcp_moderate_rcvbuf;
582extern int sysctl_tcp_tso_win_divisor;
583
584extern atomic_t tcp_memory_allocated;
585extern atomic_t tcp_sockets_allocated;
586extern int tcp_memory_pressure;
587
1da177e4
LT		 588#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
589#define TCP_INET_FAMILY(fam) ((fam) == AF_INET)
590#else
591#define TCP_INET_FAMILY(fam) 1
592#endif
593
594/*
595 * Pointers to address related TCP functions
596 * (i.e. things that depend on the address family)
597 */
598
599struct tcp_func {
600 int (*queue_xmit) (struct sk_buff *skb,
601 int ipfragok);
602
603 void (*send_check) (struct sock *sk,
604 struct tcphdr *th,
605 int len,
606 struct sk_buff *skb);
607
608 int (*rebuild_header) (struct sock *sk);
609
610 int (*conn_request) (struct sock *sk,
611 struct sk_buff *skb);
612
613 struct sock * (*syn_recv_sock) (struct sock *sk,
614 struct sk_buff *skb,
60236fdd 615 struct request_sock *req,
1da177e4
LT		 616 struct dst_entry *dst);
617
618 int (*remember_stamp) (struct sock *sk);
619
620 __u16 net_header_len;
621
622 int (*setsockopt) (struct sock *sk,
623 int level,
624 int optname,
625 char __user *optval,
626 int optlen);
627
628 int (*getsockopt) (struct sock *sk,
629 int level,
630 int optname,
631 char __user *optval,
632 int __user *optlen);
633
634
635 void (*addr2sockaddr) (struct sock *sk,
636 struct sockaddr *);
637
638 int sockaddr_len;
639};
640
641/*
642 * The next routines deal with comparing 32 bit unsigned ints
643 * and worry about wraparound (automatic with unsigned arithmetic).
644 */
645
646static inline int before(__u32 seq1, __u32 seq2)
647{
648 return (__s32)(seq1-seq2) < 0;
649}
650
651static inline int after(__u32 seq1, __u32 seq2)
652{
653 return (__s32)(seq2-seq1) < 0;
654}
655
656
657/* is s2<=s1<=s3 ? */
658static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
659{
660 return seq3 - seq2 >= seq1 - seq2;
661}
662
663
664extern struct proto tcp_prot;
665
666DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
667#define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
668#define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
669#define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
670#define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
671#define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
672#define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
673
674extern void tcp_put_port(struct sock *sk);
675extern void tcp_inherit_port(struct sock *sk, struct sock *child);
676
677extern void tcp_v4_err(struct sk_buff *skb, u32);
678
679extern void tcp_shutdown (struct sock *sk, int how);
680
681extern int tcp_v4_rcv(struct sk_buff *skb);
682
683extern int tcp_v4_remember_stamp(struct sock *sk);
684
685extern int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw);
686
687extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk,
688 struct msghdr *msg, size_t size);
689extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
690
691extern int tcp_ioctl(struct sock *sk,
692 int cmd,
693 unsigned long arg);
694
695extern int tcp_rcv_state_process(struct sock *sk,
696 struct sk_buff *skb,
697 struct tcphdr *th,
698 unsigned len);
699
700extern int tcp_rcv_established(struct sock *sk,
701 struct sk_buff *skb,
702 struct tcphdr *th,
703 unsigned len);
704
705extern void tcp_rcv_space_adjust(struct sock *sk);
706
707enum tcp_ack_state_t
708{
709 TCP_ACK_SCHED = 1,
710 TCP_ACK_TIMER = 2,
711 TCP_ACK_PUSHED= 4
712};
713
714static inline void tcp_schedule_ack(struct tcp_sock *tp)
715{
716 tp->ack.pending |= TCP_ACK_SCHED;
717}
718
719static inline int tcp_ack_scheduled(struct tcp_sock *tp)
720{
721 return tp->ack.pending&TCP_ACK_SCHED;
722}
723
fc6415bc 724static __inline__ void tcp_dec_quickack_mode(struct tcp_sock *tp, unsigned int pkts)
1da177e4 725{
fc6415bc
DM		 726 if (tp->ack.quick) {
727 if (pkts >= tp->ack.quick) {
728 tp->ack.quick = 0;
729
730 /* Leaving quickack mode we deflate ATO. */
731 tp->ack.ato = TCP_ATO_MIN;
732 } else
733 tp->ack.quick -= pkts;
1da177e4
LT		 734 }
735}
736
737extern void tcp_enter_quickack_mode(struct tcp_sock *tp);
738
739static __inline__ void tcp_delack_init(struct tcp_sock *tp)
740{
741 memset(&tp->ack, 0, sizeof(tp->ack));
742}
743
744static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
745{
746 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
747}
748
749enum tcp_tw_status
750{
751 TCP_TW_SUCCESS = 0,
752 TCP_TW_RST = 1,
753 TCP_TW_ACK = 2,
754 TCP_TW_SYN = 3
755};
756
757
758extern enum tcp_tw_status tcp_timewait_state_process(struct tcp_tw_bucket *tw,
759 struct sk_buff *skb,
760 struct tcphdr *th,
761 unsigned len);
762
763extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
60236fdd
ACM		 764 struct request_sock *req,
765 struct request_sock **prev);
1da177e4
LT		 766extern int tcp_child_process(struct sock *parent,
767 struct sock *child,
768 struct sk_buff *skb);
769extern void tcp_enter_frto(struct sock *sk);
770extern void tcp_enter_loss(struct sock *sk, int how);
771extern void tcp_clear_retrans(struct tcp_sock *tp);
772extern void tcp_update_metrics(struct sock *sk);
773
774extern void tcp_close(struct sock *sk,
775 long timeout);
776extern struct sock * tcp_accept(struct sock *sk, int flags, int *err);
777extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
778
779extern int tcp_getsockopt(struct sock *sk, int level,
780 int optname,
781 char __user *optval,
782 int __user *optlen);
783extern int tcp_setsockopt(struct sock *sk, int level,
784 int optname, char __user *optval,
785 int optlen);
786extern void tcp_set_keepalive(struct sock *sk, int val);
787extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
788 struct msghdr *msg,
789 size_t len, int nonblock,
790 int flags, int *addr_len);
791
792extern int tcp_listen_start(struct sock *sk);
793
794extern void tcp_parse_options(struct sk_buff *skb,
795 struct tcp_options_received *opt_rx,
796 int estab);
797
798/*
799 * TCP v4 functions exported for the inet6 API
800 */
801
802extern int tcp_v4_rebuild_header(struct sock *sk);
803
804extern int tcp_v4_build_header(struct sock *sk,
805 struct sk_buff *skb);
806
807extern void tcp_v4_send_check(struct sock *sk,
808 struct tcphdr *th, int len,
809 struct sk_buff *skb);
810
811extern int tcp_v4_conn_request(struct sock *sk,
812 struct sk_buff *skb);
813
814extern struct sock * tcp_create_openreq_child(struct sock *sk,
60236fdd 815 struct request_sock *req,
1da177e4
LT		 816 struct sk_buff *skb);
817
818extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
819 struct sk_buff *skb,
60236fdd 820 struct request_sock *req,
1da177e4
LT		 821 struct dst_entry *dst);
822
823extern int tcp_v4_do_rcv(struct sock *sk,
824 struct sk_buff *skb);
825
826extern int tcp_v4_connect(struct sock *sk,
827 struct sockaddr *uaddr,
828 int addr_len);
829
830extern int tcp_connect(struct sock *sk);
831
832extern struct sk_buff * tcp_make_synack(struct sock *sk,
833 struct dst_entry *dst,
60236fdd 834 struct request_sock *req);
1da177e4
LT		 835
836extern int tcp_disconnect(struct sock *sk, int flags);
837
838extern void tcp_unhash(struct sock *sk);
839
840extern int tcp_v4_hash_connecting(struct sock *sk);
841
842
843/* From syncookies.c */
844extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
845 struct ip_options *opt);
846extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
847 __u16 *mss);
848
849/* tcp_output.c */
850
851extern int tcp_write_xmit(struct sock *, int nonagle);
852extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
853extern void tcp_xmit_retransmit_queue(struct sock *);
854extern void tcp_simple_retransmit(struct sock *);
855extern int tcp_trim_head(struct sock *, struct sk_buff *, u32);
856
857extern void tcp_send_probe0(struct sock *);
858extern void tcp_send_partial(struct sock *);
859extern int tcp_write_wakeup(struct sock *);
860extern void tcp_send_fin(struct sock *sk);
861extern void tcp_send_active_reset(struct sock *sk, int priority);
862extern int tcp_send_synack(struct sock *);
863extern void tcp_push_one(struct sock *, unsigned mss_now);
864extern void tcp_send_ack(struct sock *sk);
865extern void tcp_send_delayed_ack(struct sock *sk);
866
867/* tcp_timer.c */
868extern void tcp_init_xmit_timers(struct sock *);
869extern void tcp_clear_xmit_timers(struct sock *);
870
871extern void tcp_delete_keepalive_timer(struct sock *);
872extern void tcp_reset_keepalive_timer(struct sock *, unsigned long);
873extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu);
874extern unsigned int tcp_current_mss(struct sock *sk, int large);
875
876#ifdef TCP_DEBUG
877extern const char tcp_timer_bug_msg[];
878#endif
879
880/* tcp_diag.c */
881extern void tcp_get_info(struct sock *, struct tcp_info *);
882
883/* Read 'sendfile()'-style from a TCP socket */
884typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
885 unsigned int, size_t);
886extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
887 sk_read_actor_t recv_actor);
888
889static inline void tcp_clear_xmit_timer(struct sock *sk, int what)
890{
891 struct tcp_sock *tp = tcp_sk(sk);
892
893 switch (what) {
894 case TCP_TIME_RETRANS:
895 case TCP_TIME_PROBE0:
896 tp->pending = 0;
897
898#ifdef TCP_CLEAR_TIMERS
899 sk_stop_timer(sk, &tp->retransmit_timer);
900#endif
901 break;
902 case TCP_TIME_DACK:
903 tp->ack.blocked = 0;
904 tp->ack.pending = 0;
905
906#ifdef TCP_CLEAR_TIMERS
907 sk_stop_timer(sk, &tp->delack_timer);
908#endif
909 break;
910 default:
911#ifdef TCP_DEBUG
912 printk(tcp_timer_bug_msg);
913#endif
914 return;
915 };
916
917}
918
919/*
920 * Reset the retransmission timer
921 */
922static inline void tcp_reset_xmit_timer(struct sock *sk, int what, unsigned long when)
923{
924 struct tcp_sock *tp = tcp_sk(sk);
925
926 if (when > TCP_RTO_MAX) {
927#ifdef TCP_DEBUG
928 printk(KERN_DEBUG "reset_xmit_timer sk=%p %d when=0x%lx, caller=%p\n", sk, what, when, current_text_addr());
929#endif
930 when = TCP_RTO_MAX;
931 }
932
933 switch (what) {
934 case TCP_TIME_RETRANS:
935 case TCP_TIME_PROBE0:
936 tp->pending = what;
937 tp->timeout = jiffies+when;
938 sk_reset_timer(sk, &tp->retransmit_timer, tp->timeout);
939 break;
940
941 case TCP_TIME_DACK:
942 tp->ack.pending |= TCP_ACK_TIMER;
943 tp->ack.timeout = jiffies+when;
944 sk_reset_timer(sk, &tp->delack_timer, tp->ack.timeout);
945 break;
946
947 default:
948#ifdef TCP_DEBUG
949 printk(tcp_timer_bug_msg);
950#endif
951 return;
952 };
953}
954
955/* Initialize RCV_MSS value.
956 * RCV_MSS is an our guess about MSS used by the peer.
957 * We haven't any direct information about the MSS.
958 * It's better to underestimate the RCV_MSS rather than overestimate.
959 * Overestimations make us ACKing less frequently than needed.
960 * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss().
961 */
962
963static inline void tcp_initialize_rcv_mss(struct sock *sk)
964{
965 struct tcp_sock *tp = tcp_sk(sk);
966 unsigned int hint = min(tp->advmss, tp->mss_cache_std);
967
968 hint = min(hint, tp->rcv_wnd/2);
969 hint = min(hint, TCP_MIN_RCVMSS);
970 hint = max(hint, TCP_MIN_MSS);
971
972 tp->ack.rcv_mss = hint;
973}
974
975static __inline__ void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
976{
977 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
978 ntohl(TCP_FLAG_ACK) |
979 snd_wnd);
980}
981
982static __inline__ void tcp_fast_path_on(struct tcp_sock *tp)
983{
984 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale);
985}
986
987static inline void tcp_fast_path_check(struct sock *sk, struct tcp_sock *tp)
988{
989 if (skb_queue_len(&tp->out_of_order_queue) == 0 &&
990 tp->rcv_wnd &&
991 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
992 !tp->urg_data)
993 tcp_fast_path_on(tp);
994}
995
996/* Compute the actual receive window we are currently advertising.
997 * Rcv_nxt can be after the window if our peer push more data
998 * than the offered window.
999 */
1000static __inline__ u32 tcp_receive_window(const struct tcp_sock *tp)
1001{
1002 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
1003
1004 if (win < 0)
1005 win = 0;
1006 return (u32) win;
1007}
1008
1009/* Choose a new window, without checks for shrinking, and without
1010 * scaling applied to the result. The caller does these things
1011 * if necessary. This is a "raw" window selection.
1012 */
1013extern u32 __tcp_select_window(struct sock *sk);
1014
1015/* TCP timestamps are only 32-bits, this causes a slight
1016 * complication on 64-bit systems since we store a snapshot
1017 * of jiffies in the buffer control blocks below. We decidely
1018 * only use of the low 32-bits of jiffies and hide the ugly
1019 * casts with the following macro.
1020 */
1021#define tcp_time_stamp ((__u32)(jiffies))
1022
1023/* This is what the send packet queueing engine uses to pass
1024 * TCP per-packet control information to the transmission
1025 * code. We also store the host-order sequence numbers in
1026 * here too. This is 36 bytes on 32-bit architectures,
1027 * 40 bytes on 64-bit machines, if this grows please adjust
1028 * skbuff.h:skbuff->cb[xxx] size appropriately.
1029 */
1030struct tcp_skb_cb {
1031 union {
1032 struct inet_skb_parm h4;
1033#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
1034 struct inet6_skb_parm h6;
1035#endif
1036 } header; /* For incoming frames */
1037 __u32 seq; /* Starting sequence number */
1038 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
1039 __u32 when; /* used to compute rtt's */
1040 __u8 flags; /* TCP header flags. */
1041
1042 /* NOTE: These must match up to the flags byte in a
1043 * real TCP header.
1044 */
1045#define TCPCB_FLAG_FIN 0x01
1046#define TCPCB_FLAG_SYN 0x02
1047#define TCPCB_FLAG_RST 0x04
1048#define TCPCB_FLAG_PSH 0x08
1049#define TCPCB_FLAG_ACK 0x10
1050#define TCPCB_FLAG_URG 0x20
1051#define TCPCB_FLAG_ECE 0x40
1052#define TCPCB_FLAG_CWR 0x80
1053
1054 __u8 sacked; /* State flags for SACK/FACK. */
1055#define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
1056#define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
1057#define TCPCB_LOST 0x04 /* SKB is lost */
1058#define TCPCB_TAGBITS 0x07 /* All tag bits */
1059
1060#define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
1061#define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
1062
1063#define TCPCB_URG 0x20 /* Urgent pointer advenced here */
1064
1065#define TCPCB_AT_TAIL (TCPCB_URG)
1066
1067 __u16 urg_ptr; /* Valid w/URG flags is set. */
1068 __u32 ack_seq; /* Sequence number ACK'd */
1069};
1070
1071#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
1072
1073#include <net/tcp_ecn.h>
1074
1075/* Due to TSO, an SKB can be composed of multiple actual
1076 * packets. To keep these tracked properly, we use this.
1077 */
1078static inline int tcp_skb_pcount(const struct sk_buff *skb)
1079{
1080 return skb_shinfo(skb)->tso_segs;
1081}
1082
1083/* This is valid iff tcp_skb_pcount() > 1. */
1084static inline int tcp_skb_mss(const struct sk_buff *skb)
1085{
1086 return skb_shinfo(skb)->tso_size;
1087}
1088
1089static inline void tcp_dec_pcount_approx(__u32 *count,
1090 const struct sk_buff *skb)
1091{
1092 if (*count) {
1093 *count -= tcp_skb_pcount(skb);
1094 if ((int)*count < 0)
1095 *count = 0;
1096 }
1097}
1098
1099static inline void tcp_packets_out_inc(struct sock *sk,
1100 struct tcp_sock *tp,
1101 const struct sk_buff *skb)
1102{
1103 int orig = tp->packets_out;
1104
1105 tp->packets_out += tcp_skb_pcount(skb);
1106 if (!orig)
1107 tcp_reset_xmit_timer(sk, TCP_TIME_RETRANS, tp->rto);
1108}
1109
1110static inline void tcp_packets_out_dec(struct tcp_sock *tp,
1111 const struct sk_buff *skb)
1112{
1113 tp->packets_out -= tcp_skb_pcount(skb);
1114}
1115
317a76f9
SH		 1116/* Events passed to congestion control interface */
1117enum tcp_ca_event {
1118 CA_EVENT_TX_START, /* first transmit when no packets in flight */
1119 CA_EVENT_CWND_RESTART, /* congestion window restart */
1120 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
1121 CA_EVENT_FRTO, /* fast recovery timeout */
1122 CA_EVENT_LOSS, /* loss timeout */
1123 CA_EVENT_FAST_ACK, /* in sequence ack */
1124 CA_EVENT_SLOW_ACK, /* other ack */
1125};
1126
1127/*
1128 * Interface for adding new TCP congestion control handlers
1129 */
1130#define TCP_CA_NAME_MAX 16
1131struct tcp_congestion_ops {
1132 struct list_head list;
1133
1134 /* initialize private data (optional) */
1135 void (*init)(struct tcp_sock *tp);
1136 /* cleanup private data (optional) */
1137 void (*release)(struct tcp_sock *tp);
1138
1139 /* return slow start threshold (required) */
1140 u32 (*ssthresh)(struct tcp_sock *tp);
1141 /* lower bound for congestion window (optional) */
1142 u32 (*min_cwnd)(struct tcp_sock *tp);
1143 /* do new cwnd calculation (required) */
1144 void (*cong_avoid)(struct tcp_sock *tp, u32 ack,
1145 u32 rtt, u32 in_flight, int good_ack);
1146 /* round trip time sample per acked packet (optional) */
1147 void (*rtt_sample)(struct tcp_sock *tp, u32 usrtt);
1148 /* call before changing ca_state (optional) */
1149 void (*set_state)(struct tcp_sock *tp, u8 new_state);
1150 /* call when cwnd event occurs (optional) */
1151 void (*cwnd_event)(struct tcp_sock *tp, enum tcp_ca_event ev);
1152 /* new value of cwnd after loss (optional) */
1153 u32 (*undo_cwnd)(struct tcp_sock *tp);
1154 /* hook for packet ack accounting (optional) */
1155 void (*pkts_acked)(struct tcp_sock *tp, u32 num_acked);
1156 /* get info for tcp_diag (optional) */
1157 void (*get_info)(struct tcp_sock *tp, u32 ext, struct sk_buff *skb);
1158
1159 char name[TCP_CA_NAME_MAX];
1160 struct module *owner;
1161};
1162
1163extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
1164extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
1165
1166extern void tcp_init_congestion_control(struct tcp_sock *tp);
1167extern void tcp_cleanup_congestion_control(struct tcp_sock *tp);
1168extern int tcp_set_default_congestion_control(const char *name);
1169extern void tcp_get_default_congestion_control(char *name);
5f8ef48d 1170extern int tcp_set_congestion_control(struct tcp_sock *tp, const char *name);
317a76f9 1171
5f8ef48d 1172extern struct tcp_congestion_ops tcp_init_congestion_ops;
317a76f9
SH		 1173extern u32 tcp_reno_ssthresh(struct tcp_sock *tp);
1174extern void tcp_reno_cong_avoid(struct tcp_sock *tp, u32 ack,
1175 u32 rtt, u32 in_flight, int flag);
1176extern u32 tcp_reno_min_cwnd(struct tcp_sock *tp);
a8acfbac 1177extern struct tcp_congestion_ops tcp_reno;
317a76f9
SH		 1178
1179static inline void tcp_set_ca_state(struct tcp_sock *tp, u8 ca_state)
1180{
1181 if (tp->ca_ops->set_state)
1182 tp->ca_ops->set_state(tp, ca_state);
1183 tp->ca_state = ca_state;
1184}
1185
1186static inline void tcp_ca_event(struct tcp_sock *tp, enum tcp_ca_event event)
1187{
1188 if (tp->ca_ops->cwnd_event)
1189 tp->ca_ops->cwnd_event(tp, event);
1190}
1191
1da177e4
LT		 1192/* This determines how many packets are "in the network" to the best
1193 * of our knowledge. In many cases it is conservative, but where
1194 * detailed information is available from the receiver (via SACK
1195 * blocks etc.) we can make more aggressive calculations.
1196 *
1197 * Use this for decisions involving congestion control, use just
1198 * tp->packets_out to determine if the send queue is empty or not.
1199 *
1200 * Read this equation as:
1201 *
1202 * "Packets sent once on transmission queue" MINUS
1203 * "Packets left network, but not honestly ACKed yet" PLUS
1204 * "Packets fast retransmitted"
1205 */
1206static __inline__ unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
1207{
1208 return (tp->packets_out - tp->left_out + tp->retrans_out);
1209}
1210
1da177e4
LT		 1211/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
1212 * The exception is rate halving phase, when cwnd is decreasing towards
1213 * ssthresh.
1214 */
1215static inline __u32 tcp_current_ssthresh(struct tcp_sock *tp)
1216{
1217 if ((1<<tp->ca_state)&(TCPF_CA_CWR|TCPF_CA_Recovery))
1218 return tp->snd_ssthresh;
1219 else
1220 return max(tp->snd_ssthresh,
1221 ((tp->snd_cwnd >> 1) +
1222 (tp->snd_cwnd >> 2)));
1223}
1224
1225static inline void tcp_sync_left_out(struct tcp_sock *tp)
1226{
1227 if (tp->rx_opt.sack_ok &&
1228 (tp->sacked_out >= tp->packets_out - tp->lost_out))
1229 tp->sacked_out = tp->packets_out - tp->lost_out;
1230 tp->left_out = tp->sacked_out + tp->lost_out;
1231}
1232
1233extern void tcp_cwnd_application_limited(struct sock *sk);
1234
1235/* Congestion window validation. (RFC2861) */
1236
1237static inline void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp)
1238{
1239 __u32 packets_out = tp->packets_out;
1240
1241 if (packets_out >= tp->snd_cwnd) {
1242 /* Network is feed fully. */
1243 tp->snd_cwnd_used = 0;
1244 tp->snd_cwnd_stamp = tcp_time_stamp;
1245 } else {
1246 /* Network starves. */
1247 if (tp->packets_out > tp->snd_cwnd_used)
1248 tp->snd_cwnd_used = tp->packets_out;
1249
1250 if ((s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= tp->rto)
1251 tcp_cwnd_application_limited(sk);
1252 }
1253}
1254
1255/* Set slow start threshould and cwnd not falling to slow start */
1256static inline void __tcp_enter_cwr(struct tcp_sock *tp)
1257{
1258 tp->undo_marker = 0;
317a76f9 1259 tp->snd_ssthresh = tp->ca_ops->ssthresh(tp);
1da177e4
LT		 1260 tp->snd_cwnd = min(tp->snd_cwnd,
1261 tcp_packets_in_flight(tp) + 1U);
1262 tp->snd_cwnd_cnt = 0;
1263 tp->high_seq = tp->snd_nxt;
1264 tp->snd_cwnd_stamp = tcp_time_stamp;
1265 TCP_ECN_queue_cwr(tp);
1266}
1267
1268static inline void tcp_enter_cwr(struct tcp_sock *tp)
1269{
1270 tp->prior_ssthresh = 0;
1271 if (tp->ca_state < TCP_CA_CWR) {
1272 __tcp_enter_cwr(tp);
1273 tcp_set_ca_state(tp, TCP_CA_CWR);
1274 }
1275}
1276
1277extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);
1278
1279/* Slow start with delack produces 3 packets of burst, so that
1280 * it is safe "de facto".
1281 */
1282static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp)
1283{
1284 return 3;
1285}
1286
1287static __inline__ int tcp_minshall_check(const struct tcp_sock *tp)
1288{
1289 return after(tp->snd_sml,tp->snd_una) &&
1290 !after(tp->snd_sml, tp->snd_nxt);
1291}
1292
1293static __inline__ void tcp_minshall_update(struct tcp_sock *tp, int mss,
1294 const struct sk_buff *skb)
1295{
1296 if (skb->len < mss)
1297 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
1298}
1299
1300/* Return 0, if packet can be sent now without violation Nagle's rules:
1301 1. It is full sized.
1302 2. Or it contains FIN.
1303 3. Or TCP_NODELAY was set.
1304 4. Or TCP_CORK is not set, and all sent packets are ACKed.
1305 With Minshall's modification: all sent small packets are ACKed.
1306 */
1307
1308static __inline__ int
1309tcp_nagle_check(const struct tcp_sock *tp, const struct sk_buff *skb,
1310 unsigned mss_now, int nonagle)
1311{
1312 return (skb->len < mss_now &&
1313 !(TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) &&
1314 ((nonagle&TCP_NAGLE_CORK) ||
1315 (!nonagle &&
1316 tp->packets_out &&
1317 tcp_minshall_check(tp))));
1318}
1319
d5ac99a6 1320extern void tcp_set_skb_tso_segs(struct sock *, struct sk_buff *);
1da177e4
LT		 1321
1322/* This checks if the data bearing packet SKB (usually sk->sk_send_head)
1323 * should be put on the wire right now.
1324 */
d5ac99a6 1325static __inline__ int tcp_snd_test(struct sock *sk,
1da177e4
LT		 1326 struct sk_buff *skb,
1327 unsigned cur_mss, int nonagle)
1328{
d5ac99a6 1329 struct tcp_sock *tp = tcp_sk(sk);
1da177e4
LT		 1330 int pkts = tcp_skb_pcount(skb);
1331
1332 if (!pkts) {
d5ac99a6 1333 tcp_set_skb_tso_segs(sk, skb);
1da177e4
LT		 1334 pkts = tcp_skb_pcount(skb);
1335 }
1336
1337 /* RFC 1122 - section 4.2.3.4
1338 *
1339 * We must queue if
1340 *
1341 * a) The right edge of this frame exceeds the window
1342 * b) There are packets in flight and we have a small segment
1343 * [SWS avoidance and Nagle algorithm]
1344 * (part of SWS is done on packetization)
1345 * Minshall version sounds: there are no _small_
1346 * segments in flight. (tcp_nagle_check)
1347 * c) We have too many packets 'in flight'
1348 *
1349 * Don't use the nagle rule for urgent data (or
1350 * for the final FIN -DaveM).
1351 *
1352 * Also, Nagle rule does not apply to frames, which
1353 * sit in the middle of queue (they have no chances
1354 * to get new data) and if room at tail of skb is
1355 * not enough to save something seriously (<32 for now).
1356 */
1357
1358 /* Don't be strict about the congestion window for the
1359 * final FIN frame. -DaveM
1360 */
1361 return (((nonagle&TCP_NAGLE_PUSH) || tp->urg_mode
1362 || !tcp_nagle_check(tp, skb, cur_mss, nonagle)) &&
1363 (((tcp_packets_in_flight(tp) + (pkts-1)) < tp->snd_cwnd) ||
1364 (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)) &&
1365 !after(TCP_SKB_CB(skb)->end_seq, tp->snd_una + tp->snd_wnd));
1366}
1367
1368static __inline__ void tcp_check_probe_timer(struct sock *sk, struct tcp_sock *tp)
1369{
1370 if (!tp->packets_out && !tp->pending)
1371 tcp_reset_xmit_timer(sk, TCP_TIME_PROBE0, tp->rto);
1372}
1373
1374static __inline__ int tcp_skb_is_last(const struct sock *sk,
1375 const struct sk_buff *skb)
1376{
1377 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1378}
1379
1380/* Push out any pending frames which were held back due to
1381 * TCP_CORK or attempt at coalescing tiny packets.
1382 * The socket must be locked by the caller.
1383 */
1384static __inline__ void __tcp_push_pending_frames(struct sock *sk,
1385 struct tcp_sock *tp,
1386 unsigned cur_mss,
1387 int nonagle)
1388{
1389 struct sk_buff *skb = sk->sk_send_head;
1390
1391 if (skb) {
1392 if (!tcp_skb_is_last(sk, skb))
1393 nonagle = TCP_NAGLE_PUSH;
d5ac99a6 1394 if (!tcp_snd_test(sk, skb, cur_mss, nonagle) ||
1da177e4
LT		 1395 tcp_write_xmit(sk, nonagle))
1396 tcp_check_probe_timer(sk, tp);
1397 }
1398 tcp_cwnd_validate(sk, tp);
1399}
1400
1401static __inline__ void tcp_push_pending_frames(struct sock *sk,
1402 struct tcp_sock *tp)
1403{
1404 __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle);
1405}
1406
1407static __inline__ int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp)
1408{
1409 struct sk_buff *skb = sk->sk_send_head;
1410
1411 return (skb &&
d5ac99a6 1412 tcp_snd_test(sk, skb, tcp_current_mss(sk, 1),
1da177e4
LT		 1413 tcp_skb_is_last(sk, skb) ? TCP_NAGLE_PUSH : tp->nonagle));
1414}
1415
1416static __inline__ void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq)
1417{
1418 tp->snd_wl1 = seq;
1419}
1420
1421static __inline__ void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq)
1422{
1423 tp->snd_wl1 = seq;
1424}
1425
1426extern void tcp_destroy_sock(struct sock *sk);
1427
1428
1429/*
1430 * Calculate(/check) TCP checksum
1431 */
1432static __inline__ u16 tcp_v4_check(struct tcphdr *th, int len,
1433 unsigned long saddr, unsigned long daddr,
1434 unsigned long base)
1435{
1436 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
1437}
1438
1439static __inline__ int __tcp_checksum_complete(struct sk_buff *skb)
1440{
1441 return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
1442}
1443
1444static __inline__ int tcp_checksum_complete(struct sk_buff *skb)
1445{
1446 return skb->ip_summed != CHECKSUM_UNNECESSARY &&
1447 __tcp_checksum_complete(skb);
1448}
1449
1450/* Prequeue for VJ style copy to user, combined with checksumming. */
1451
1452static __inline__ void tcp_prequeue_init(struct tcp_sock *tp)
1453{
1454 tp->ucopy.task = NULL;
1455 tp->ucopy.len = 0;
1456 tp->ucopy.memory = 0;
1457 skb_queue_head_init(&tp->ucopy.prequeue);
1458}
1459
1460/* Packet is added to VJ-style prequeue for processing in process
1461 * context, if a reader task is waiting. Apparently, this exciting
1462 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1463 * failed somewhere. Latency? Burstiness? Well, at least now we will
1464 * see, why it failed. 8)8) --ANK
1465 *
1466 * NOTE: is this not too big to inline?
1467 */
1468static __inline__ int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1469{
1470 struct tcp_sock *tp = tcp_sk(sk);
1471
1472 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
1473 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1474 tp->ucopy.memory += skb->truesize;
1475 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1476 struct sk_buff *skb1;
1477
1478 BUG_ON(sock_owned_by_user(sk));
1479
1480 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1481 sk->sk_backlog_rcv(sk, skb1);
1482 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED);
1483 }
1484
1485 tp->ucopy.memory = 0;
1486 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1487 wake_up_interruptible(sk->sk_sleep);
1488 if (!tcp_ack_scheduled(tp))
1489 tcp_reset_xmit_timer(sk, TCP_TIME_DACK, (3*TCP_RTO_MIN)/4);
1490 }
1491 return 1;
1492 }
1493 return 0;
1494}
1495
1496
1497#undef STATE_TRACE
1498
1499#ifdef STATE_TRACE
1500static const char *statename[]={
1501 "Unused","Established","Syn Sent","Syn Recv",
1502 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
1503 "Close Wait","Last ACK","Listen","Closing"
1504};
1505#endif
1506
1507static __inline__ void tcp_set_state(struct sock *sk, int state)
1508{
1509 int oldstate = sk->sk_state;
1510
1511 switch (state) {
1512 case TCP_ESTABLISHED:
1513 if (oldstate != TCP_ESTABLISHED)
1514 TCP_INC_STATS(TCP_MIB_CURRESTAB);
1515 break;
1516
1517 case TCP_CLOSE:
1518 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1519 TCP_INC_STATS(TCP_MIB_ESTABRESETS);
1520
1521 sk->sk_prot->unhash(sk);
1522 if (tcp_sk(sk)->bind_hash &&
1523 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1524 tcp_put_port(sk);
1525 /* fall through */
1526 default:
1527 if (oldstate==TCP_ESTABLISHED)
1528 TCP_DEC_STATS(TCP_MIB_CURRESTAB);
1529 }
1530
1531 /* Change state AFTER socket is unhashed to avoid closed
1532 * socket sitting in hash tables.
1533 */
1534 sk->sk_state = state;
1535
1536#ifdef STATE_TRACE
1537 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]);
1538#endif
1539}
1540
1541static __inline__ void tcp_done(struct sock *sk)
1542{
1543 tcp_set_state(sk, TCP_CLOSE);
1544 tcp_clear_xmit_timers(sk);
1545
1546 sk->sk_shutdown = SHUTDOWN_MASK;
1547
1548 if (!sock_flag(sk, SOCK_DEAD))
1549 sk->sk_state_change(sk);
1550 else
1551 tcp_destroy_sock(sk);
1552}
1553
1554static __inline__ void tcp_sack_reset(struct tcp_options_received *rx_opt)
1555{
1556 rx_opt->dsack = 0;
1557 rx_opt->eff_sacks = 0;
1558 rx_opt->num_sacks = 0;
1559}
1560
1561static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp, __u32 tstamp)
1562{
1563 if (tp->rx_opt.tstamp_ok) {
1564 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) |
1565 (TCPOPT_NOP << 16) |
1566 (TCPOPT_TIMESTAMP << 8) |
1567 TCPOLEN_TIMESTAMP);
1568 *ptr++ = htonl(tstamp);
1569 *ptr++ = htonl(tp->rx_opt.ts_recent);
1570 }
1571 if (tp->rx_opt.eff_sacks) {
1572 struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks;
1573 int this_sack;
1574
1575 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) |
1576 (TCPOPT_NOP << 16) |
1577 (TCPOPT_SACK << 8) |
1578 (TCPOLEN_SACK_BASE +
1579 (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK)));
1580 for(this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) {
1581 *ptr++ = htonl(sp[this_sack].start_seq);
1582 *ptr++ = htonl(sp[this_sack].end_seq);
1583 }
1584 if (tp->rx_opt.dsack) {
1585 tp->rx_opt.dsack = 0;
1586 tp->rx_opt.eff_sacks--;
1587 }
1588 }
1589}
1590
1591/* Construct a tcp options header for a SYN or SYN_ACK packet.
1592 * If this is every changed make sure to change the definition of
1593 * MAX_SYN_SIZE to match the new maximum number of options that you
1594 * can generate.
1595 */
1596static inline void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack,
1597 int offer_wscale, int wscale, __u32 tstamp, __u32 ts_recent)
1598{
1599 /* We always get an MSS option.
1600 * The option bytes which will be seen in normal data
1601 * packets should timestamps be used, must be in the MSS
1602 * advertised. But we subtract them from tp->mss_cache so
1603 * that calculations in tcp_sendmsg are simpler etc.
1604 * So account for this fact here if necessary. If we
1605 * don't do this correctly, as a receiver we won't
1606 * recognize data packets as being full sized when we
1607 * should, and thus we won't abide by the delayed ACK
1608 * rules correctly.
1609 * SACKs don't matter, we never delay an ACK when we
1610 * have any of those going out.
1611 */
1612 *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss);
1613 if (ts) {
1614 if(sack)
1615 *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) |
1616 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1617 else
1618 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1619 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1620 *ptr++ = htonl(tstamp); /* TSVAL */
1621 *ptr++ = htonl(ts_recent); /* TSECR */
1622 } else if(sack)
1623 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1624 (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM);
1625 if (offer_wscale)
1626 *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale));
1627}
1628
1629/* Determine a window scaling and initial window to offer. */
1630extern void tcp_select_initial_window(int __space, __u32 mss,
1631 __u32 *rcv_wnd, __u32 *window_clamp,
1632 int wscale_ok, __u8 *rcv_wscale);
1633
1634static inline int tcp_win_from_space(int space)
1635{
1636 return sysctl_tcp_adv_win_scale<=0 ?
1637 (space>>(-sysctl_tcp_adv_win_scale)) :
1638 space - (space>>sysctl_tcp_adv_win_scale);
1639}
1640
1641/* Note: caller must be prepared to deal with negative returns */
1642static inline int tcp_space(const struct sock *sk)
1643{
1644 return tcp_win_from_space(sk->sk_rcvbuf -
1645 atomic_read(&sk->sk_rmem_alloc));
1646}
1647
1648static inline int tcp_full_space(const struct sock *sk)
1649{
1650 return tcp_win_from_space(sk->sk_rcvbuf);
1651}
1652
60236fdd 1653static inline void tcp_acceptq_queue(struct sock *sk, struct request_sock *req,
1da177e4
LT		 1654 struct sock *child)
1655{
0e87506f 1656 reqsk_queue_add(&tcp_sk(sk)->accept_queue, req, sk, child);
1da177e4
LT		 1657}
1658
1da177e4 1659static inline void
60236fdd 1660tcp_synq_removed(struct sock *sk, struct request_sock *req)
1da177e4 1661{
0e87506f 1662 if (reqsk_queue_removed(&tcp_sk(sk)->accept_queue, req) == 0)
1da177e4 1663 tcp_delete_keepalive_timer(sk);
1da177e4
LT		 1664}
1665
1666static inline void tcp_synq_added(struct sock *sk)
1667{
0e87506f 1668 if (reqsk_queue_added(&tcp_sk(sk)->accept_queue) == 0)
1da177e4 1669 tcp_reset_keepalive_timer(sk, TCP_TIMEOUT_INIT);
1da177e4
LT		 1670}
1671
1672static inline int tcp_synq_len(struct sock *sk)
1673{
0e87506f 1674 return reqsk_queue_len(&tcp_sk(sk)->accept_queue);
1da177e4
LT		 1675}
1676
1677static inline int tcp_synq_young(struct sock *sk)
1678{
0e87506f 1679 return reqsk_queue_len_young(&tcp_sk(sk)->accept_queue);
1da177e4
LT		 1680}
1681
1682static inline int tcp_synq_is_full(struct sock *sk)
1683{
0e87506f 1684 return reqsk_queue_is_full(&tcp_sk(sk)->accept_queue);
1da177e4
LT		 1685}
1686
60236fdd 1687static inline void tcp_synq_unlink(struct tcp_sock *tp, struct request_sock *req,
0e87506f 1688 struct request_sock **prev)
1da177e4 1689{
0e87506f 1690 reqsk_queue_unlink(&tp->accept_queue, req, prev);
1da177e4
LT		 1691}
1692
60236fdd
ACM		 1693static inline void tcp_synq_drop(struct sock *sk, struct request_sock *req,
1694 struct request_sock **prev)
1da177e4
LT		 1695{
1696 tcp_synq_unlink(tcp_sk(sk), req, prev);
1697 tcp_synq_removed(sk, req);
60236fdd 1698 reqsk_free(req);
1da177e4
LT		 1699}
1700
60236fdd 1701static __inline__ void tcp_openreq_init(struct request_sock *req,
1da177e4
LT		 1702 struct tcp_options_received *rx_opt,
1703 struct sk_buff *skb)
1704{
2e6599cb
ACM		 1705 struct inet_request_sock *ireq = inet_rsk(req);
1706
1da177e4 1707 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
2e6599cb 1708 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
1da177e4
LT		 1709 req->mss = rx_opt->mss_clamp;
1710 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
2e6599cb
ACM		 1711 ireq->tstamp_ok = rx_opt->tstamp_ok;
1712 ireq->sack_ok = rx_opt->sack_ok;
1713 ireq->snd_wscale = rx_opt->snd_wscale;
1714 ireq->wscale_ok = rx_opt->wscale_ok;
1715 ireq->acked = 0;
1716 ireq->ecn_ok = 0;
1717 ireq->rmt_port = skb->h.th->source;
1da177e4
LT		 1718}
1719
1720extern void tcp_enter_memory_pressure(void);
1721
1722extern void tcp_listen_wlock(void);
1723
1724/* - We may sleep inside this lock.
1725 * - If sleeping is not required (or called from BH),
1726 * use plain read_(un)lock(&tcp_lhash_lock).
1727 */
1728
1729static inline void tcp_listen_lock(void)
1730{
1731 /* read_lock synchronizes to candidates to writers */
1732 read_lock(&tcp_lhash_lock);
1733 atomic_inc(&tcp_lhash_users);
1734 read_unlock(&tcp_lhash_lock);
1735}
1736
1737static inline void tcp_listen_unlock(void)
1738{
1739 if (atomic_dec_and_test(&tcp_lhash_users))
1740 wake_up(&tcp_lhash_wait);
1741}
1742
1743static inline int keepalive_intvl_when(const struct tcp_sock *tp)
1744{
1745 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
1746}
1747
1748static inline int keepalive_time_when(const struct tcp_sock *tp)
1749{
1750 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
1751}
1752
1753static inline int tcp_fin_time(const struct tcp_sock *tp)
1754{
1755 int fin_timeout = tp->linger2 ? : sysctl_tcp_fin_timeout;
1756
1757 if (fin_timeout < (tp->rto<<2) - (tp->rto>>1))
1758 fin_timeout = (tp->rto<<2) - (tp->rto>>1);
1759
1760 return fin_timeout;
1761}
1762
1763static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
1764{
1765 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
1766 return 0;
1767 if (xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
1768 return 0;
1769
1770 /* RST segments are not recommended to carry timestamp,
1771 and, if they do, it is recommended to ignore PAWS because
1772 "their cleanup function should take precedence over timestamps."
1773 Certainly, it is mistake. It is necessary to understand the reasons
1774 of this constraint to relax it: if peer reboots, clock may go
1775 out-of-sync and half-open connections will not be reset.
1776 Actually, the problem would be not existing if all
1777 the implementations followed draft about maintaining clock
1778 via reboots. Linux-2.2 DOES NOT!
1779
1780 However, we can relax time bounds for RST segments to MSL.
1781 */
1782 if (rst && xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL)
1783 return 0;
1784 return 1;
1785}
1786
1787static inline void tcp_v4_setup_caps(struct sock *sk, struct dst_entry *dst)
1788{
1789 sk->sk_route_caps = dst->dev->features;
1790 if (sk->sk_route_caps & NETIF_F_TSO) {
1791 if (sock_flag(sk, SOCK_NO_LARGESEND) || dst->header_len)
1792 sk->sk_route_caps &= ~NETIF_F_TSO;
1793 }
1794}
1795
1796#define TCP_CHECK_TIMER(sk) do { } while (0)
1797
1798static inline int tcp_use_frto(const struct sock *sk)
1799{
1800 const struct tcp_sock *tp = tcp_sk(sk);
1801
1802 /* F-RTO must be activated in sysctl and there must be some
1803 * unsent new data, and the advertised window should allow
1804 * sending it.
1805 */
1806 return (sysctl_tcp_frto && sk->sk_send_head &&
1807 !after(TCP_SKB_CB(sk->sk_send_head)->end_seq,
1808 tp->snd_una + tp->snd_wnd));
1809}
1810
1811static inline void tcp_mib_init(void)
1812{
1813 /* See RFC 2012 */
1814 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1);
1815 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
1816 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
1817 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
1818}
1819
1820/* /proc */
1821enum tcp_seq_states {
1822 TCP_SEQ_STATE_LISTENING,
1823 TCP_SEQ_STATE_OPENREQ,
1824 TCP_SEQ_STATE_ESTABLISHED,
1825 TCP_SEQ_STATE_TIME_WAIT,
1826};
1827
1828struct tcp_seq_afinfo {
1829 struct module *owner;
1830 char *name;
1831 sa_family_t family;
1832 int (*seq_show) (struct seq_file *m, void *v);
1833 struct file_operations *seq_fops;
1834};
1835
1836struct tcp_iter_state {
1837 sa_family_t family;
1838 enum tcp_seq_states state;
1839 struct sock *syn_wait_sk;
1840 int bucket, sbucket, num, uid;
1841 struct seq_operations seq_ops;
1842};
1843
1844extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo);
1845extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo);
1846
1da177e4 1847#endif /* _TCP_H */
kernel source for telekom puls (alcatel/mediatek)