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.
6 * Definitions for the TCP module.
8 * Version: @(#)tcp.h 1.0.5 05/23/93
10 * Authors: Ross Biro, <bir7@leland.Stanford.Edu>
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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.
22 #define FASTRETRANS_DEBUG 1
24 /* Cancel timers, when they are not required. */
25 #undef TCP_CLEAR_TIMERS
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>
37 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
38 #include <linux/ipv6.h>
40 #include <linux/seq_file.h>
42 /* This is for all connections with a full identity, no wildcards.
43 * New scheme, half the table is for TIME_WAIT, the other half is
44 * for the rest. I'll experiment with dynamic table growth later.
46 struct tcp_ehash_bucket {
48 struct hlist_head chain;
49 } __attribute__((__aligned__(8)));
51 /* This is for listening sockets, thus all sockets which possess wildcards. */
52 #define TCP_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */
54 /* There are a few simple rules, which allow for local port reuse by
55 * an application. In essence:
57 * 1) Sockets bound to different interfaces may share a local port.
58 * Failing that, goto test 2.
59 * 2) If all sockets have sk->sk_reuse set, and none of them are in
60 * TCP_LISTEN state, the port may be shared.
61 * Failing that, goto test 3.
62 * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local
63 * address, and none of them are the same, the port may be
65 * Failing this, the port cannot be shared.
67 * The interesting point, is test #2. This is what an FTP server does
68 * all day. To optimize this case we use a specific flag bit defined
69 * below. As we add sockets to a bind bucket list, we perform a
70 * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN))
71 * As long as all sockets added to a bind bucket pass this test,
72 * the flag bit will be set.
73 * The resulting situation is that tcp_v[46]_verify_bind() can just check
74 * for this flag bit, if it is set and the socket trying to bind has
75 * sk->sk_reuse set, we don't even have to walk the owners list at all,
76 * we return that it is ok to bind this socket to the requested local port.
78 * Sounds like a lot of work, but it is worth it. In a more naive
79 * implementation (ie. current FreeBSD etc.) the entire list of ports
80 * must be walked for each data port opened by an ftp server. Needless
81 * to say, this does not scale at all. With a couple thousand FTP
82 * users logged onto your box, isn't it nice to know that new data
83 * ports are created in O(1) time? I thought so. ;-) -DaveM
85 struct tcp_bind_bucket {
87 signed short fastreuse;
88 struct hlist_node node;
89 struct hlist_head owners;
92 #define tb_for_each(tb, node, head) hlist_for_each_entry(tb, node, head, node)
94 struct tcp_bind_hashbucket {
96 struct hlist_head chain;
99 static inline struct tcp_bind_bucket *__tb_head(struct tcp_bind_hashbucket *head)
101 return hlist_entry(head->chain.first, struct tcp_bind_bucket, node);
104 static inline struct tcp_bind_bucket *tb_head(struct tcp_bind_hashbucket *head)
106 return hlist_empty(&head->chain) ? NULL : __tb_head(head);
109 extern struct tcp_hashinfo {
110 /* This is for sockets with full identity only. Sockets here will
111 * always be without wildcards and will have the following invariant:
113 * TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE
115 * First half of the table is for sockets not in TIME_WAIT, second half
116 * is for TIME_WAIT sockets only.
118 struct tcp_ehash_bucket *__tcp_ehash;
120 /* Ok, let's try this, I give up, we do need a local binding
121 * TCP hash as well as the others for fast bind/connect.
123 struct tcp_bind_hashbucket *__tcp_bhash;
125 int __tcp_bhash_size;
126 int __tcp_ehash_size;
128 /* All sockets in TCP_LISTEN state will be in here. This is the only
129 * table where wildcard'd TCP sockets can exist. Hash function here
130 * is just local port number.
132 struct hlist_head __tcp_listening_hash[TCP_LHTABLE_SIZE];
134 /* All the above members are written once at bootup and
135 * never written again _or_ are predominantly read-access.
137 * Now align to a new cache line as all the following members
140 rwlock_t __tcp_lhash_lock ____cacheline_aligned;
141 atomic_t __tcp_lhash_users;
142 wait_queue_head_t __tcp_lhash_wait;
143 spinlock_t __tcp_portalloc_lock;
146 #define tcp_ehash (tcp_hashinfo.__tcp_ehash)
147 #define tcp_bhash (tcp_hashinfo.__tcp_bhash)
148 #define tcp_ehash_size (tcp_hashinfo.__tcp_ehash_size)
149 #define tcp_bhash_size (tcp_hashinfo.__tcp_bhash_size)
150 #define tcp_listening_hash (tcp_hashinfo.__tcp_listening_hash)
151 #define tcp_lhash_lock (tcp_hashinfo.__tcp_lhash_lock)
152 #define tcp_lhash_users (tcp_hashinfo.__tcp_lhash_users)
153 #define tcp_lhash_wait (tcp_hashinfo.__tcp_lhash_wait)
154 #define tcp_portalloc_lock (tcp_hashinfo.__tcp_portalloc_lock)
156 /* SLAB cache for TCP socks */
157 extern kmem_cache_t *tcp_sk_cachep;
159 extern kmem_cache_t *tcp_bucket_cachep;
160 extern struct tcp_bind_bucket *tcp_bucket_create(struct tcp_bind_hashbucket *head,
161 unsigned short snum);
162 extern void tcp_bucket_destroy(struct tcp_bind_bucket *tb);
163 extern void tcp_bucket_unlock(struct sock *sk);
164 extern int tcp_port_rover;
165 extern struct sock *tcp_v4_lookup_listener(u32 addr, unsigned short hnum, int dif);
167 /* These are AF independent. */
168 static __inline__ int tcp_bhashfn(__u16 lport)
170 return (lport & (tcp_bhash_size - 1));
173 extern void tcp_bind_hash(struct sock *sk, struct tcp_bind_bucket *tb,
174 unsigned short snum);
176 #if (BITS_PER_LONG == 64)
177 #define TCP_ADDRCMP_ALIGN_BYTES 8
179 #define TCP_ADDRCMP_ALIGN_BYTES 4
182 /* This is a TIME_WAIT bucket. It works around the memory consumption
183 * problems of sockets in such a state on heavily loaded servers, but
184 * without violating the protocol specification.
186 struct tcp_tw_bucket {
188 * Now struct sock also uses sock_common, so please just
189 * don't add nothing before this first member (__tw_common) --acme
191 struct sock_common __tw_common;
192 #define tw_family __tw_common.skc_family
193 #define tw_state __tw_common.skc_state
194 #define tw_reuse __tw_common.skc_reuse
195 #define tw_bound_dev_if __tw_common.skc_bound_dev_if
196 #define tw_node __tw_common.skc_node
197 #define tw_bind_node __tw_common.skc_bind_node
198 #define tw_refcnt __tw_common.skc_refcnt
199 #define tw_xid __tw_common.skc_xid
200 #define tw_vx_info __tw_common.skc_vx_info
201 #define tw_nid __tw_common.skc_nid
202 #define tw_nx_info __tw_common.skc_nx_info
203 volatile unsigned char tw_substate;
204 unsigned char tw_rcv_wscale;
206 /* Socket demultiplex comparisons on incoming packets. */
207 /* these five are in inet_opt */
209 __attribute__((aligned(TCP_ADDRCMP_ALIGN_BYTES)));
213 /* And these are ours. */
220 long tw_ts_recent_stamp;
221 unsigned long tw_ttd;
222 struct tcp_bind_bucket *tw_tb;
223 struct hlist_node tw_death_node;
224 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
225 struct in6_addr tw_v6_daddr;
226 struct in6_addr tw_v6_rcv_saddr;
231 static __inline__ void tw_add_node(struct tcp_tw_bucket *tw,
232 struct hlist_head *list)
234 hlist_add_head(&tw->tw_node, list);
237 static __inline__ void tw_add_bind_node(struct tcp_tw_bucket *tw,
238 struct hlist_head *list)
240 hlist_add_head(&tw->tw_bind_node, list);
243 static inline int tw_dead_hashed(struct tcp_tw_bucket *tw)
245 return tw->tw_death_node.pprev != NULL;
248 static __inline__ void tw_dead_node_init(struct tcp_tw_bucket *tw)
250 tw->tw_death_node.pprev = NULL;
253 static __inline__ void __tw_del_dead_node(struct tcp_tw_bucket *tw)
255 __hlist_del(&tw->tw_death_node);
256 tw_dead_node_init(tw);
259 static __inline__ int tw_del_dead_node(struct tcp_tw_bucket *tw)
261 if (tw_dead_hashed(tw)) {
262 __tw_del_dead_node(tw);
268 #define tw_for_each(tw, node, head) \
269 hlist_for_each_entry(tw, node, head, tw_node)
271 #define tw_for_each_inmate(tw, node, jail) \
272 hlist_for_each_entry(tw, node, jail, tw_death_node)
274 #define tw_for_each_inmate_safe(tw, node, safe, jail) \
275 hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
277 #define tcptw_sk(__sk) ((struct tcp_tw_bucket *)(__sk))
279 static inline u32 tcp_v4_rcv_saddr(const struct sock *sk)
281 return likely(sk->sk_state != TCP_TIME_WAIT) ?
282 inet_sk(sk)->rcv_saddr : tcptw_sk(sk)->tw_rcv_saddr;
285 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
286 static inline struct in6_addr *__tcp_v6_rcv_saddr(const struct sock *sk)
288 return likely(sk->sk_state != TCP_TIME_WAIT) ?
289 &inet6_sk(sk)->rcv_saddr : &tcptw_sk(sk)->tw_v6_rcv_saddr;
292 static inline struct in6_addr *tcp_v6_rcv_saddr(const struct sock *sk)
294 return sk->sk_family == AF_INET6 ? __tcp_v6_rcv_saddr(sk) : NULL;
297 #define tcptw_sk_ipv6only(__sk) (tcptw_sk(__sk)->tw_v6_ipv6only)
299 static inline int tcp_v6_ipv6only(const struct sock *sk)
301 return likely(sk->sk_state != TCP_TIME_WAIT) ?
302 ipv6_only_sock(sk) : tcptw_sk_ipv6only(sk);
305 # define __tcp_v6_rcv_saddr(__sk) NULL
306 # define tcp_v6_rcv_saddr(__sk) NULL
307 # define tcptw_sk_ipv6only(__sk) 0
308 # define tcp_v6_ipv6only(__sk) 0
311 extern kmem_cache_t *tcp_timewait_cachep;
313 static inline void tcp_tw_put(struct tcp_tw_bucket *tw)
315 if (atomic_dec_and_test(&tw->tw_refcnt)) {
316 #ifdef INET_REFCNT_DEBUG
317 printk(KERN_DEBUG "tw_bucket %p released\n", tw);
319 kmem_cache_free(tcp_timewait_cachep, tw);
323 extern atomic_t tcp_orphan_count;
324 extern int tcp_tw_count;
325 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
326 extern void tcp_tw_schedule(struct tcp_tw_bucket *tw, int timeo);
327 extern void tcp_tw_deschedule(struct tcp_tw_bucket *tw);
330 /* Socket demux engine toys. */
332 #define TCP_COMBINED_PORTS(__sport, __dport) \
333 (((__u32)(__sport)<<16) | (__u32)(__dport))
334 #else /* __LITTLE_ENDIAN */
335 #define TCP_COMBINED_PORTS(__sport, __dport) \
336 (((__u32)(__dport)<<16) | (__u32)(__sport))
339 #if (BITS_PER_LONG == 64)
341 #define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) \
342 __u64 __name = (((__u64)(__saddr))<<32)|((__u64)(__daddr));
343 #else /* __LITTLE_ENDIAN */
344 #define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) \
345 __u64 __name = (((__u64)(__daddr))<<32)|((__u64)(__saddr));
346 #endif /* __BIG_ENDIAN */
347 #define TCP_IPV4_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
348 (((*((__u64 *)&(inet_sk(__sk)->daddr)))== (__cookie)) && \
349 ((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \
350 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
351 #define TCP_IPV4_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
352 (((*((__u64 *)&(tcptw_sk(__sk)->tw_daddr))) == (__cookie)) && \
353 ((*((__u32 *)&(tcptw_sk(__sk)->tw_dport))) == (__ports)) && \
354 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
355 #else /* 32-bit arch */
356 #define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr)
357 #define TCP_IPV4_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
358 ((inet_sk(__sk)->daddr == (__saddr)) && \
359 (inet_sk(__sk)->rcv_saddr == (__daddr)) && \
360 ((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \
361 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
362 #define TCP_IPV4_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\
363 ((tcptw_sk(__sk)->tw_daddr == (__saddr)) && \
364 (tcptw_sk(__sk)->tw_rcv_saddr == (__daddr)) && \
365 ((*((__u32 *)&(tcptw_sk(__sk)->tw_dport))) == (__ports)) && \
366 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
367 #endif /* 64-bit arch */
369 #define TCP_IPV6_MATCH(__sk, __saddr, __daddr, __ports, __dif) \
370 (((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \
371 ((__sk)->sk_family == AF_INET6) && \
372 !ipv6_addr_cmp(&inet6_sk(__sk)->daddr, (__saddr)) && \
373 !ipv6_addr_cmp(&inet6_sk(__sk)->rcv_saddr, (__daddr)) && \
374 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
376 /* These can have wildcards, don't try too hard. */
377 static __inline__ int tcp_lhashfn(unsigned short num)
379 return num & (TCP_LHTABLE_SIZE - 1);
382 static __inline__ int tcp_sk_listen_hashfn(struct sock *sk)
384 return tcp_lhashfn(inet_sk(sk)->num);
387 #define MAX_TCP_HEADER (128 + MAX_HEADER)
390 * Never offer a window over 32767 without using window scaling. Some
391 * poor stacks do signed 16bit maths!
393 #define MAX_TCP_WINDOW 32767U
395 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
396 #define TCP_MIN_MSS 88U
398 /* Minimal RCV_MSS. */
399 #define TCP_MIN_RCVMSS 536U
401 /* After receiving this amount of duplicate ACKs fast retransmit starts. */
402 #define TCP_FASTRETRANS_THRESH 3
404 /* Maximal reordering. */
405 #define TCP_MAX_REORDERING 127
407 /* Maximal number of ACKs sent quickly to accelerate slow-start. */
408 #define TCP_MAX_QUICKACKS 16U
410 /* urg_data states */
411 #define TCP_URG_VALID 0x0100
412 #define TCP_URG_NOTYET 0x0200
413 #define TCP_URG_READ 0x0400
415 #define TCP_RETR1 3 /*
416 * This is how many retries it does before it
417 * tries to figure out if the gateway is
418 * down. Minimal RFC value is 3; it corresponds
419 * to ~3sec-8min depending on RTO.
422 #define TCP_RETR2 15 /*
423 * This should take at least
424 * 90 minutes to time out.
425 * RFC1122 says that the limit is 100 sec.
426 * 15 is ~13-30min depending on RTO.
429 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a
430 * connection: ~180sec is RFC minumum */
432 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a
433 * connection: ~180sec is RFC minumum */
436 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned
437 * socket. 7 is ~50sec-16min.
441 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
442 * state, about 60 seconds */
443 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN
444 /* BSD style FIN_WAIT2 deadlock breaker.
445 * It used to be 3min, new value is 60sec,
446 * to combine FIN-WAIT-2 timeout with
450 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */
452 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */
453 #define TCP_ATO_MIN ((unsigned)(HZ/25))
455 #define TCP_DELACK_MIN 4U
456 #define TCP_ATO_MIN 4U
458 #define TCP_RTO_MAX ((unsigned)(120*HZ))
459 #define TCP_RTO_MIN ((unsigned)(HZ/5))
460 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */
462 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes
463 * for local resources.
466 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */
467 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */
468 #define TCP_KEEPALIVE_INTVL (75*HZ)
470 #define MAX_TCP_KEEPIDLE 32767
471 #define MAX_TCP_KEEPINTVL 32767
472 #define MAX_TCP_KEEPCNT 127
473 #define MAX_TCP_SYNCNT 127
475 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */
476 #define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */
478 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24)
479 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated
480 * after this time. It should be equal
481 * (or greater than) TCP_TIMEWAIT_LEN
482 * to provide reliability equal to one
483 * provided by timewait state.
485 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host
486 * timestamps. It must be less than
487 * minimal timewait lifetime.
490 #define TCP_TW_RECYCLE_SLOTS_LOG 5
491 #define TCP_TW_RECYCLE_SLOTS (1<<TCP_TW_RECYCLE_SLOTS_LOG)
493 /* If time > 4sec, it is "slow" path, no recycling is required,
494 so that we select tick to get range about 4 seconds.
497 #if HZ <= 16 || HZ > 4096
498 # error Unsupported: HZ <= 16 or HZ > 4096
500 # define TCP_TW_RECYCLE_TICK (5+2-TCP_TW_RECYCLE_SLOTS_LOG)
502 # define TCP_TW_RECYCLE_TICK (6+2-TCP_TW_RECYCLE_SLOTS_LOG)
504 # define TCP_TW_RECYCLE_TICK (7+2-TCP_TW_RECYCLE_SLOTS_LOG)
506 # define TCP_TW_RECYCLE_TICK (8+2-TCP_TW_RECYCLE_SLOTS_LOG)
508 # define TCP_TW_RECYCLE_TICK (9+2-TCP_TW_RECYCLE_SLOTS_LOG)
510 # define TCP_TW_RECYCLE_TICK (10+2-TCP_TW_RECYCLE_SLOTS_LOG)
512 # define TCP_TW_RECYCLE_TICK (11+2-TCP_TW_RECYCLE_SLOTS_LOG)
514 # define TCP_TW_RECYCLE_TICK (12+2-TCP_TW_RECYCLE_SLOTS_LOG)
517 #define BICTCP_1_OVER_BETA 8 /*
519 * multiplicative decrease factor
521 #define BICTCP_MAX_INCREMENT 32 /*
522 * Limit on the amount of
523 * increment allowed during
526 #define BICTCP_FUNC_OF_MIN_INCR 11 /*
527 * log(B/Smin)/log(B/(B-1))+1,
531 #define BICTCP_B 4 /*
533 * go to point (max+min)/N
540 #define TCPOPT_NOP 1 /* Padding */
541 #define TCPOPT_EOL 0 /* End of options */
542 #define TCPOPT_MSS 2 /* Segment size negotiating */
543 #define TCPOPT_WINDOW 3 /* Window scaling */
544 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
545 #define TCPOPT_SACK 5 /* SACK Block */
546 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
552 #define TCPOLEN_MSS 4
553 #define TCPOLEN_WINDOW 3
554 #define TCPOLEN_SACK_PERM 2
555 #define TCPOLEN_TIMESTAMP 10
557 /* But this is what stacks really send out. */
558 #define TCPOLEN_TSTAMP_ALIGNED 12
559 #define TCPOLEN_WSCALE_ALIGNED 4
560 #define TCPOLEN_SACKPERM_ALIGNED 4
561 #define TCPOLEN_SACK_BASE 2
562 #define TCPOLEN_SACK_BASE_ALIGNED 4
563 #define TCPOLEN_SACK_PERBLOCK 8
565 #define TCP_TIME_RETRANS 1 /* Retransmit timer */
566 #define TCP_TIME_DACK 2 /* Delayed ack timer */
567 #define TCP_TIME_PROBE0 3 /* Zero window probe timer */
568 #define TCP_TIME_KEEPOPEN 4 /* Keepalive timer */
570 /* Flags in tp->nonagle */
571 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */
572 #define TCP_NAGLE_CORK 2 /* Socket is corked */
573 #define TCP_NAGLE_PUSH 4 /* Cork is overriden for already queued data */
575 /* sysctl variables for tcp */
576 extern int sysctl_max_syn_backlog;
577 extern int sysctl_tcp_timestamps;
578 extern int sysctl_tcp_window_scaling;
579 extern int sysctl_tcp_sack;
580 extern int sysctl_tcp_fin_timeout;
581 extern int sysctl_tcp_tw_recycle;
582 extern int sysctl_tcp_keepalive_time;
583 extern int sysctl_tcp_keepalive_probes;
584 extern int sysctl_tcp_keepalive_intvl;
585 extern int sysctl_tcp_syn_retries;
586 extern int sysctl_tcp_synack_retries;
587 extern int sysctl_tcp_retries1;
588 extern int sysctl_tcp_retries2;
589 extern int sysctl_tcp_orphan_retries;
590 extern int sysctl_tcp_syncookies;
591 extern int sysctl_tcp_retrans_collapse;
592 extern int sysctl_tcp_stdurg;
593 extern int sysctl_tcp_rfc1337;
594 extern int sysctl_tcp_abort_on_overflow;
595 extern int sysctl_tcp_max_orphans;
596 extern int sysctl_tcp_max_tw_buckets;
597 extern int sysctl_tcp_fack;
598 extern int sysctl_tcp_reordering;
599 extern int sysctl_tcp_ecn;
600 extern int sysctl_tcp_dsack;
601 extern int sysctl_tcp_mem[3];
602 extern int sysctl_tcp_wmem[3];
603 extern int sysctl_tcp_rmem[3];
604 extern int sysctl_tcp_app_win;
605 extern int sysctl_tcp_adv_win_scale;
606 extern int sysctl_tcp_tw_reuse;
607 extern int sysctl_tcp_frto;
608 extern int sysctl_tcp_low_latency;
609 extern int sysctl_tcp_westwood;
610 extern int sysctl_tcp_vegas_cong_avoid;
611 extern int sysctl_tcp_vegas_alpha;
612 extern int sysctl_tcp_vegas_beta;
613 extern int sysctl_tcp_vegas_gamma;
614 extern int sysctl_tcp_nometrics_save;
615 extern int sysctl_tcp_bic;
616 extern int sysctl_tcp_bic_fast_convergence;
617 extern int sysctl_tcp_bic_low_window;
618 extern int sysctl_tcp_default_win_scale;
619 extern int sysctl_tcp_moderate_rcvbuf;
621 extern atomic_t tcp_memory_allocated;
622 extern atomic_t tcp_sockets_allocated;
623 extern int tcp_memory_pressure;
627 struct or_calltable {
629 int (*rtx_syn_ack) (struct sock *sk, struct open_request *req, struct dst_entry*);
630 void (*send_ack) (struct sk_buff *skb, struct open_request *req);
631 void (*destructor) (struct open_request *req);
632 void (*send_reset) (struct sk_buff *skb);
635 struct tcp_v4_open_req {
638 struct ip_options *opt;
641 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
642 struct tcp_v6_open_req {
643 struct in6_addr loc_addr;
644 struct in6_addr rmt_addr;
645 struct sk_buff *pktopts;
650 /* this structure is too big */
651 struct open_request {
652 struct open_request *dl_next; /* Must be first member! */
659 __u16 snd_wscale : 4,
666 /* The following two fields can be easily recomputed I think -AK */
667 __u32 window_clamp; /* window clamp at creation time */
668 __u32 rcv_wnd; /* rcv_wnd offered first time */
670 unsigned long expires;
671 struct or_calltable *class;
674 struct tcp_v4_open_req v4_req;
675 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
676 struct tcp_v6_open_req v6_req;
679 #ifdef CONFIG_ACCEPT_QUEUES
680 unsigned long acceptq_time_stamp;
685 /* SLAB cache for open requests. */
686 extern kmem_cache_t *tcp_openreq_cachep;
688 #define tcp_openreq_alloc() kmem_cache_alloc(tcp_openreq_cachep, SLAB_ATOMIC)
689 #define tcp_openreq_fastfree(req) kmem_cache_free(tcp_openreq_cachep, req)
691 static inline void tcp_openreq_free(struct open_request *req)
693 req->class->destructor(req);
694 tcp_openreq_fastfree(req);
697 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
698 #define TCP_INET_FAMILY(fam) ((fam) == AF_INET)
700 #define TCP_INET_FAMILY(fam) 1
704 * Pointers to address related TCP functions
705 * (i.e. things that depend on the address family)
709 int (*queue_xmit) (struct sk_buff *skb,
712 void (*send_check) (struct sock *sk,
715 struct sk_buff *skb);
717 int (*rebuild_header) (struct sock *sk);
719 int (*conn_request) (struct sock *sk,
720 struct sk_buff *skb);
722 struct sock * (*syn_recv_sock) (struct sock *sk,
724 struct open_request *req,
725 struct dst_entry *dst);
727 int (*remember_stamp) (struct sock *sk);
729 __u16 net_header_len;
731 int (*setsockopt) (struct sock *sk,
737 int (*getsockopt) (struct sock *sk,
744 void (*addr2sockaddr) (struct sock *sk,
751 * The next routines deal with comparing 32 bit unsigned ints
752 * and worry about wraparound (automatic with unsigned arithmetic).
755 static inline int before(__u32 seq1, __u32 seq2)
757 return (__s32)(seq1-seq2) < 0;
760 static inline int after(__u32 seq1, __u32 seq2)
762 return (__s32)(seq2-seq1) < 0;
766 /* is s2<=s1<=s3 ? */
767 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3)
769 return seq3 - seq2 >= seq1 - seq2;
773 extern struct proto tcp_prot;
775 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics);
776 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field)
777 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field)
778 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field)
779 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field)
780 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val)
781 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val)
783 extern void tcp_put_port(struct sock *sk);
784 extern void tcp_inherit_port(struct sock *sk, struct sock *child);
786 extern void tcp_v4_err(struct sk_buff *skb, u32);
788 extern void tcp_shutdown (struct sock *sk, int how);
790 extern int tcp_v4_rcv(struct sk_buff *skb);
792 extern int tcp_v4_remember_stamp(struct sock *sk);
794 extern int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw);
796 extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk,
797 struct msghdr *msg, size_t size);
798 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags);
800 extern int tcp_ioctl(struct sock *sk,
804 extern int tcp_rcv_state_process(struct sock *sk,
809 extern int tcp_rcv_established(struct sock *sk,
814 extern void tcp_rcv_space_adjust(struct sock *sk);
823 static inline void tcp_schedule_ack(struct tcp_opt *tp)
825 tp->ack.pending |= TCP_ACK_SCHED;
828 static inline int tcp_ack_scheduled(struct tcp_opt *tp)
830 return tp->ack.pending&TCP_ACK_SCHED;
833 static __inline__ void tcp_dec_quickack_mode(struct tcp_opt *tp)
835 if (tp->ack.quick && --tp->ack.quick == 0) {
836 /* Leaving quickack mode we deflate ATO. */
837 tp->ack.ato = TCP_ATO_MIN;
841 extern void tcp_enter_quickack_mode(struct tcp_opt *tp);
843 static __inline__ void tcp_delack_init(struct tcp_opt *tp)
845 memset(&tp->ack, 0, sizeof(tp->ack));
848 static inline void tcp_clear_options(struct tcp_opt *tp)
850 tp->tstamp_ok = tp->sack_ok = tp->wscale_ok = tp->snd_wscale = 0;
862 extern enum tcp_tw_status tcp_timewait_state_process(struct tcp_tw_bucket *tw,
867 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb,
868 struct open_request *req,
869 struct open_request **prev);
870 extern int tcp_child_process(struct sock *parent,
872 struct sk_buff *skb);
873 extern void tcp_enter_frto(struct sock *sk);
874 extern void tcp_enter_loss(struct sock *sk, int how);
875 extern void tcp_clear_retrans(struct tcp_opt *tp);
876 extern void tcp_update_metrics(struct sock *sk);
878 extern void tcp_close(struct sock *sk,
880 extern struct sock * tcp_accept(struct sock *sk, int flags, int *err);
881 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait);
883 extern int tcp_getsockopt(struct sock *sk, int level,
887 extern int tcp_setsockopt(struct sock *sk, int level,
888 int optname, char __user *optval,
890 extern void tcp_set_keepalive(struct sock *sk, int val);
891 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
893 size_t len, int nonblock,
894 int flags, int *addr_len);
896 extern int tcp_listen_start(struct sock *sk);
898 extern void tcp_parse_options(struct sk_buff *skb,
903 * TCP v4 functions exported for the inet6 API
906 extern int tcp_v4_rebuild_header(struct sock *sk);
908 extern int tcp_v4_build_header(struct sock *sk,
909 struct sk_buff *skb);
911 extern void tcp_v4_send_check(struct sock *sk,
912 struct tcphdr *th, int len,
913 struct sk_buff *skb);
915 extern int tcp_v4_conn_request(struct sock *sk,
916 struct sk_buff *skb);
918 extern struct sock * tcp_create_openreq_child(struct sock *sk,
919 struct open_request *req,
920 struct sk_buff *skb);
922 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk,
924 struct open_request *req,
925 struct dst_entry *dst);
927 extern int tcp_v4_do_rcv(struct sock *sk,
928 struct sk_buff *skb);
930 extern int tcp_v4_connect(struct sock *sk,
931 struct sockaddr *uaddr,
934 extern int tcp_connect(struct sock *sk);
936 extern struct sk_buff * tcp_make_synack(struct sock *sk,
937 struct dst_entry *dst,
938 struct open_request *req);
940 extern int tcp_disconnect(struct sock *sk, int flags);
942 extern void tcp_unhash(struct sock *sk);
944 extern int tcp_v4_hash_connecting(struct sock *sk);
947 /* From syncookies.c */
948 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
949 struct ip_options *opt);
950 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb,
955 extern int tcp_write_xmit(struct sock *, int nonagle);
956 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *);
957 extern void tcp_xmit_retransmit_queue(struct sock *);
958 extern void tcp_simple_retransmit(struct sock *);
960 extern void tcp_send_probe0(struct sock *);
961 extern void tcp_send_partial(struct sock *);
962 extern int tcp_write_wakeup(struct sock *);
963 extern void tcp_send_fin(struct sock *sk);
964 extern void tcp_send_active_reset(struct sock *sk, int priority);
965 extern int tcp_send_synack(struct sock *);
966 extern int tcp_transmit_skb(struct sock *, struct sk_buff *);
967 extern void tcp_push_one(struct sock *, unsigned mss_now);
968 extern void tcp_send_ack(struct sock *sk);
969 extern void tcp_send_delayed_ack(struct sock *sk);
972 extern void tcp_init_xmit_timers(struct sock *);
973 extern void tcp_clear_xmit_timers(struct sock *);
975 extern void tcp_delete_keepalive_timer (struct sock *);
976 extern void tcp_reset_keepalive_timer (struct sock *, unsigned long);
977 extern int tcp_sync_mss(struct sock *sk, u32 pmtu);
979 extern const char timer_bug_msg[];
982 extern void tcp_get_info(struct sock *, struct tcp_info *);
984 /* Read 'sendfile()'-style from a TCP socket */
985 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
986 unsigned int, size_t);
987 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
988 sk_read_actor_t recv_actor);
990 static inline void tcp_clear_xmit_timer(struct sock *sk, int what)
992 struct tcp_opt *tp = tcp_sk(sk);
995 case TCP_TIME_RETRANS:
996 case TCP_TIME_PROBE0:
999 #ifdef TCP_CLEAR_TIMERS
1000 sk_stop_timer(sk, &tp->retransmit_timer);
1004 tp->ack.blocked = 0;
1005 tp->ack.pending = 0;
1007 #ifdef TCP_CLEAR_TIMERS
1008 sk_stop_timer(sk, &tp->delack_timer);
1012 printk(timer_bug_msg);
1019 * Reset the retransmission timer
1021 static inline void tcp_reset_xmit_timer(struct sock *sk, int what, unsigned long when)
1023 struct tcp_opt *tp = tcp_sk(sk);
1025 if (when > TCP_RTO_MAX) {
1027 printk(KERN_DEBUG "reset_xmit_timer sk=%p %d when=0x%lx, caller=%p\n", sk, what, when, current_text_addr());
1033 case TCP_TIME_RETRANS:
1034 case TCP_TIME_PROBE0:
1036 tp->timeout = jiffies+when;
1037 sk_reset_timer(sk, &tp->retransmit_timer, tp->timeout);
1041 tp->ack.pending |= TCP_ACK_TIMER;
1042 tp->ack.timeout = jiffies+when;
1043 sk_reset_timer(sk, &tp->delack_timer, tp->ack.timeout);
1047 printk(timer_bug_msg);
1051 /* Compute the current effective MSS, taking SACKs and IP options,
1052 * and even PMTU discovery events into account.
1054 * LARGESEND note: !urg_mode is overkill, only frames up to snd_up
1055 * cannot be large. However, taking into account rare use of URG, this
1056 * is not a big flaw.
1059 static __inline__ unsigned int tcp_current_mss(struct sock *sk, int large)
1061 struct tcp_opt *tp = tcp_sk(sk);
1062 struct dst_entry *dst = __sk_dst_get(sk);
1063 int mss_now = large && (sk->sk_route_caps & NETIF_F_TSO) &&
1065 tp->mss_cache : tp->mss_cache_std;
1068 u32 mtu = dst_pmtu(dst);
1069 if (mtu != tp->pmtu_cookie ||
1070 tp->ext2_header_len != dst->header_len)
1071 mss_now = tcp_sync_mss(sk, mtu);
1074 mss_now -= (TCPOLEN_SACK_BASE_ALIGNED +
1075 (tp->eff_sacks * TCPOLEN_SACK_PERBLOCK));
1079 /* Initialize RCV_MSS value.
1080 * RCV_MSS is an our guess about MSS used by the peer.
1081 * We haven't any direct information about the MSS.
1082 * It's better to underestimate the RCV_MSS rather than overestimate.
1083 * Overestimations make us ACKing less frequently than needed.
1084 * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss().
1087 static inline void tcp_initialize_rcv_mss(struct sock *sk)
1089 struct tcp_opt *tp = tcp_sk(sk);
1090 unsigned int hint = min(tp->advmss, tp->mss_cache_std);
1092 hint = min(hint, tp->rcv_wnd/2);
1093 hint = min(hint, TCP_MIN_RCVMSS);
1094 hint = max(hint, TCP_MIN_MSS);
1096 tp->ack.rcv_mss = hint;
1099 static __inline__ void __tcp_fast_path_on(struct tcp_opt *tp, u32 snd_wnd)
1101 tp->pred_flags = htonl((tp->tcp_header_len << 26) |
1102 ntohl(TCP_FLAG_ACK) |
1106 static __inline__ void tcp_fast_path_on(struct tcp_opt *tp)
1108 __tcp_fast_path_on(tp, tp->snd_wnd>>tp->snd_wscale);
1111 static inline void tcp_fast_path_check(struct sock *sk, struct tcp_opt *tp)
1113 if (skb_queue_len(&tp->out_of_order_queue) == 0 &&
1115 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
1117 tcp_fast_path_on(tp);
1120 /* Compute the actual receive window we are currently advertising.
1121 * Rcv_nxt can be after the window if our peer push more data
1122 * than the offered window.
1124 static __inline__ u32 tcp_receive_window(struct tcp_opt *tp)
1126 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt;
1133 /* Choose a new window, without checks for shrinking, and without
1134 * scaling applied to the result. The caller does these things
1135 * if necessary. This is a "raw" window selection.
1137 extern u32 __tcp_select_window(struct sock *sk);
1139 /* TCP timestamps are only 32-bits, this causes a slight
1140 * complication on 64-bit systems since we store a snapshot
1141 * of jiffies in the buffer control blocks below. We decidely
1142 * only use of the low 32-bits of jiffies and hide the ugly
1143 * casts with the following macro.
1145 #define tcp_time_stamp ((__u32)(jiffies))
1147 /* This is what the send packet queueing engine uses to pass
1148 * TCP per-packet control information to the transmission
1149 * code. We also store the host-order sequence numbers in
1150 * here too. This is 36 bytes on 32-bit architectures,
1151 * 40 bytes on 64-bit machines, if this grows please adjust
1152 * skbuff.h:skbuff->cb[xxx] size appropriately.
1156 struct inet_skb_parm h4;
1157 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
1158 struct inet6_skb_parm h6;
1160 } header; /* For incoming frames */
1161 __u32 seq; /* Starting sequence number */
1162 __u32 end_seq; /* SEQ + FIN + SYN + datalen */
1163 __u32 when; /* used to compute rtt's */
1164 __u8 flags; /* TCP header flags. */
1166 /* NOTE: These must match up to the flags byte in a
1169 #define TCPCB_FLAG_FIN 0x01
1170 #define TCPCB_FLAG_SYN 0x02
1171 #define TCPCB_FLAG_RST 0x04
1172 #define TCPCB_FLAG_PSH 0x08
1173 #define TCPCB_FLAG_ACK 0x10
1174 #define TCPCB_FLAG_URG 0x20
1175 #define TCPCB_FLAG_ECE 0x40
1176 #define TCPCB_FLAG_CWR 0x80
1178 __u8 sacked; /* State flags for SACK/FACK. */
1179 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */
1180 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */
1181 #define TCPCB_LOST 0x04 /* SKB is lost */
1182 #define TCPCB_TAGBITS 0x07 /* All tag bits */
1184 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */
1185 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
1187 #define TCPCB_URG 0x20 /* Urgent pointer advenced here */
1189 #define TCPCB_AT_TAIL (TCPCB_URG)
1191 __u16 urg_ptr; /* Valid w/URG flags is set. */
1192 __u32 ack_seq; /* Sequence number ACK'd */
1195 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
1197 #include <net/tcp_ecn.h>
1199 /* This determines how many packets are "in the network" to the best
1200 * of our knowledge. In many cases it is conservative, but where
1201 * detailed information is available from the receiver (via SACK
1202 * blocks etc.) we can make more aggressive calculations.
1204 * Use this for decisions involving congestion control, use just
1205 * tp->packets_out to determine if the send queue is empty or not.
1207 * Read this equation as:
1209 * "Packets sent once on transmission queue" MINUS
1210 * "Packets left network, but not honestly ACKed yet" PLUS
1211 * "Packets fast retransmitted"
1213 static __inline__ unsigned int tcp_packets_in_flight(struct tcp_opt *tp)
1215 return tp->packets_out - tp->left_out + tp->retrans_out;
1218 /* Recalculate snd_ssthresh, we want to set it to:
1221 * one half the current congestion window, but no
1222 * less than two segments
1225 * behave like Reno until low_window is reached,
1226 * then increase congestion window slowly
1228 static inline __u32 tcp_recalc_ssthresh(struct tcp_opt *tp)
1230 if (sysctl_tcp_bic) {
1231 if (sysctl_tcp_bic_fast_convergence &&
1232 tp->snd_cwnd < tp->bictcp.last_max_cwnd)
1233 tp->bictcp.last_max_cwnd
1234 = (tp->snd_cwnd * (2*BICTCP_1_OVER_BETA-1))
1235 / (BICTCP_1_OVER_BETA/2);
1237 tp->bictcp.last_max_cwnd = tp->snd_cwnd;
1239 if (tp->snd_cwnd > sysctl_tcp_bic_low_window)
1240 return max(tp->snd_cwnd - (tp->snd_cwnd/BICTCP_1_OVER_BETA),
1244 return max(tp->snd_cwnd >> 1U, 2U);
1247 /* Stop taking Vegas samples for now. */
1248 #define tcp_vegas_disable(__tp) ((__tp)->vegas.doing_vegas_now = 0)
1250 /* Is this TCP connection using Vegas (regardless of whether it is taking
1251 * Vegas measurements at the current time)?
1253 #define tcp_is_vegas(__tp) ((__tp)->vegas.do_vegas)
1255 static inline void tcp_vegas_enable(struct tcp_opt *tp)
1257 /* There are several situations when we must "re-start" Vegas:
1259 * o when a connection is established
1261 * o after fast recovery
1262 * o when we send a packet and there is no outstanding
1263 * unacknowledged data (restarting an idle connection)
1265 * In these circumstances we cannot do a Vegas calculation at the
1266 * end of the first RTT, because any calculation we do is using
1267 * stale info -- both the saved cwnd and congestion feedback are
1270 * Instead we must wait until the completion of an RTT during
1271 * which we actually receive ACKs.
1274 /* Begin taking Vegas samples next time we send something. */
1275 tp->vegas.doing_vegas_now = 1;
1277 /* Set the beginning of the next send window. */
1278 tp->vegas.beg_snd_nxt = tp->snd_nxt;
1280 tp->vegas.cntRTT = 0;
1281 tp->vegas.minRTT = 0x7fffffff;
1284 /* Should we be taking Vegas samples right now? */
1285 #define tcp_vegas_enabled(__tp) ((__tp)->vegas.doing_vegas_now)
1287 extern void tcp_vegas_init(struct tcp_opt *tp);
1289 static inline void tcp_set_ca_state(struct tcp_opt *tp, u8 ca_state)
1291 if (tcp_is_vegas(tp)) {
1292 if (ca_state == TCP_CA_Open)
1293 tcp_vegas_enable(tp);
1295 tcp_vegas_disable(tp);
1297 tp->ca_state = ca_state;
1300 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
1301 * The exception is rate halving phase, when cwnd is decreasing towards
1304 static inline __u32 tcp_current_ssthresh(struct tcp_opt *tp)
1306 if ((1<<tp->ca_state)&(TCPF_CA_CWR|TCPF_CA_Recovery))
1307 return tp->snd_ssthresh;
1309 return max(tp->snd_ssthresh,
1310 ((tp->snd_cwnd >> 1) +
1311 (tp->snd_cwnd >> 2)));
1314 static inline void tcp_sync_left_out(struct tcp_opt *tp)
1316 if (tp->sack_ok && tp->sacked_out >= tp->packets_out - tp->lost_out)
1317 tp->sacked_out = tp->packets_out - tp->lost_out;
1318 tp->left_out = tp->sacked_out + tp->lost_out;
1321 extern void tcp_cwnd_application_limited(struct sock *sk);
1323 /* Congestion window validation. (RFC2861) */
1325 static inline void tcp_cwnd_validate(struct sock *sk, struct tcp_opt *tp)
1327 if (tp->packets_out >= tp->snd_cwnd) {
1328 /* Network is feed fully. */
1329 tp->snd_cwnd_used = 0;
1330 tp->snd_cwnd_stamp = tcp_time_stamp;
1332 /* Network starves. */
1333 if (tp->packets_out > tp->snd_cwnd_used)
1334 tp->snd_cwnd_used = tp->packets_out;
1336 if ((s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= tp->rto)
1337 tcp_cwnd_application_limited(sk);
1341 /* Set slow start threshould and cwnd not falling to slow start */
1342 static inline void __tcp_enter_cwr(struct tcp_opt *tp)
1344 tp->undo_marker = 0;
1345 tp->snd_ssthresh = tcp_recalc_ssthresh(tp);
1346 tp->snd_cwnd = min(tp->snd_cwnd,
1347 tcp_packets_in_flight(tp) + 1U);
1348 tp->snd_cwnd_cnt = 0;
1349 tp->high_seq = tp->snd_nxt;
1350 tp->snd_cwnd_stamp = tcp_time_stamp;
1351 TCP_ECN_queue_cwr(tp);
1354 static inline void tcp_enter_cwr(struct tcp_opt *tp)
1356 tp->prior_ssthresh = 0;
1357 if (tp->ca_state < TCP_CA_CWR) {
1358 __tcp_enter_cwr(tp);
1359 tcp_set_ca_state(tp, TCP_CA_CWR);
1363 extern __u32 tcp_init_cwnd(struct tcp_opt *tp, struct dst_entry *dst);
1365 /* Slow start with delack produces 3 packets of burst, so that
1366 * it is safe "de facto".
1368 static __inline__ __u32 tcp_max_burst(struct tcp_opt *tp)
1373 static __inline__ int tcp_minshall_check(struct tcp_opt *tp)
1375 return after(tp->snd_sml,tp->snd_una) &&
1376 !after(tp->snd_sml, tp->snd_nxt);
1379 static __inline__ void tcp_minshall_update(struct tcp_opt *tp, int mss, struct sk_buff *skb)
1382 tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
1385 /* Return 0, if packet can be sent now without violation Nagle's rules:
1386 1. It is full sized.
1387 2. Or it contains FIN.
1388 3. Or TCP_NODELAY was set.
1389 4. Or TCP_CORK is not set, and all sent packets are ACKed.
1390 With Minshall's modification: all sent small packets are ACKed.
1393 static __inline__ int
1394 tcp_nagle_check(struct tcp_opt *tp, struct sk_buff *skb, unsigned mss_now, int nonagle)
1396 return (skb->len < mss_now &&
1397 !(TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) &&
1398 ((nonagle&TCP_NAGLE_CORK) ||
1401 tcp_minshall_check(tp))));
1404 /* This checks if the data bearing packet SKB (usually sk->sk_send_head)
1405 * should be put on the wire right now.
1407 static __inline__ int tcp_snd_test(struct tcp_opt *tp, struct sk_buff *skb,
1408 unsigned cur_mss, int nonagle)
1410 /* RFC 1122 - section 4.2.3.4
1414 * a) The right edge of this frame exceeds the window
1415 * b) There are packets in flight and we have a small segment
1416 * [SWS avoidance and Nagle algorithm]
1417 * (part of SWS is done on packetization)
1418 * Minshall version sounds: there are no _small_
1419 * segments in flight. (tcp_nagle_check)
1420 * c) We have too many packets 'in flight'
1422 * Don't use the nagle rule for urgent data (or
1423 * for the final FIN -DaveM).
1425 * Also, Nagle rule does not apply to frames, which
1426 * sit in the middle of queue (they have no chances
1427 * to get new data) and if room at tail of skb is
1428 * not enough to save something seriously (<32 for now).
1431 /* Don't be strict about the congestion window for the
1432 * final FIN frame. -DaveM
1434 return (((nonagle&TCP_NAGLE_PUSH) || tp->urg_mode
1435 || !tcp_nagle_check(tp, skb, cur_mss, nonagle)) &&
1436 ((tcp_packets_in_flight(tp) < tp->snd_cwnd) ||
1437 (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)) &&
1438 !after(TCP_SKB_CB(skb)->end_seq, tp->snd_una + tp->snd_wnd));
1441 static __inline__ void tcp_check_probe_timer(struct sock *sk, struct tcp_opt *tp)
1443 if (!tp->packets_out && !tp->pending)
1444 tcp_reset_xmit_timer(sk, TCP_TIME_PROBE0, tp->rto);
1447 static __inline__ int tcp_skb_is_last(struct sock *sk, struct sk_buff *skb)
1449 return skb->next == (struct sk_buff *)&sk->sk_write_queue;
1452 /* Push out any pending frames which were held back due to
1453 * TCP_CORK or attempt at coalescing tiny packets.
1454 * The socket must be locked by the caller.
1456 static __inline__ void __tcp_push_pending_frames(struct sock *sk,
1461 struct sk_buff *skb = sk->sk_send_head;
1464 if (!tcp_skb_is_last(sk, skb))
1465 nonagle = TCP_NAGLE_PUSH;
1466 if (!tcp_snd_test(tp, skb, cur_mss, nonagle) ||
1467 tcp_write_xmit(sk, nonagle))
1468 tcp_check_probe_timer(sk, tp);
1470 tcp_cwnd_validate(sk, tp);
1473 static __inline__ void tcp_push_pending_frames(struct sock *sk,
1476 __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle);
1479 static __inline__ int tcp_may_send_now(struct sock *sk, struct tcp_opt *tp)
1481 struct sk_buff *skb = sk->sk_send_head;
1484 tcp_snd_test(tp, skb, tcp_current_mss(sk, 1),
1485 tcp_skb_is_last(sk, skb) ? TCP_NAGLE_PUSH : tp->nonagle));
1488 static __inline__ void tcp_init_wl(struct tcp_opt *tp, u32 ack, u32 seq)
1493 static __inline__ void tcp_update_wl(struct tcp_opt *tp, u32 ack, u32 seq)
1498 extern void tcp_destroy_sock(struct sock *sk);
1502 * Calculate(/check) TCP checksum
1504 static __inline__ u16 tcp_v4_check(struct tcphdr *th, int len,
1505 unsigned long saddr, unsigned long daddr,
1508 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base);
1511 static __inline__ int __tcp_checksum_complete(struct sk_buff *skb)
1513 return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
1516 static __inline__ int tcp_checksum_complete(struct sk_buff *skb)
1518 return skb->ip_summed != CHECKSUM_UNNECESSARY &&
1519 __tcp_checksum_complete(skb);
1522 /* Prequeue for VJ style copy to user, combined with checksumming. */
1524 static __inline__ void tcp_prequeue_init(struct tcp_opt *tp)
1526 tp->ucopy.task = NULL;
1528 tp->ucopy.memory = 0;
1529 skb_queue_head_init(&tp->ucopy.prequeue);
1532 /* Packet is added to VJ-style prequeue for processing in process
1533 * context, if a reader task is waiting. Apparently, this exciting
1534 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1535 * failed somewhere. Latency? Burstiness? Well, at least now we will
1536 * see, why it failed. 8)8) --ANK
1538 * NOTE: is this not too big to inline?
1540 static __inline__ int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1542 struct tcp_opt *tp = tcp_sk(sk);
1544 if (!sysctl_tcp_low_latency && tp->ucopy.task) {
1545 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1546 tp->ucopy.memory += skb->truesize;
1547 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1548 struct sk_buff *skb1;
1550 BUG_ON(sock_owned_by_user(sk));
1552 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1553 sk->sk_backlog_rcv(sk, skb1);
1554 NET_INC_STATS_BH(TCPPrequeueDropped);
1557 tp->ucopy.memory = 0;
1558 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1559 wake_up_interruptible(sk->sk_sleep);
1560 if (!tcp_ack_scheduled(tp))
1561 tcp_reset_xmit_timer(sk, TCP_TIME_DACK, (3*TCP_RTO_MIN)/4);
1572 static char *statename[]={
1573 "Unused","Established","Syn Sent","Syn Recv",
1574 "Fin Wait 1","Fin Wait 2","Time Wait", "Close",
1575 "Close Wait","Last ACK","Listen","Closing"
1579 static __inline__ void tcp_set_state(struct sock *sk, int state)
1581 int oldstate = sk->sk_state;
1584 case TCP_ESTABLISHED:
1585 if (oldstate != TCP_ESTABLISHED)
1586 TCP_INC_STATS(TcpCurrEstab);
1590 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1591 TCP_INC_STATS(TcpEstabResets);
1593 sk->sk_prot->unhash(sk);
1594 if (tcp_sk(sk)->bind_hash &&
1595 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1599 if (oldstate==TCP_ESTABLISHED)
1600 TCP_DEC_STATS(TcpCurrEstab);
1603 /* Change state AFTER socket is unhashed to avoid closed
1604 * socket sitting in hash tables.
1606 sk->sk_state = state;
1609 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]);
1613 static __inline__ void tcp_done(struct sock *sk)
1615 tcp_set_state(sk, TCP_CLOSE);
1616 tcp_clear_xmit_timers(sk);
1618 sk->sk_shutdown = SHUTDOWN_MASK;
1620 if (!sock_flag(sk, SOCK_DEAD))
1621 sk->sk_state_change(sk);
1623 tcp_destroy_sock(sk);
1626 static __inline__ void tcp_sack_reset(struct tcp_opt *tp)
1633 static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_opt *tp, __u32 tstamp)
1635 if (tp->tstamp_ok) {
1636 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) |
1637 (TCPOPT_NOP << 16) |
1638 (TCPOPT_TIMESTAMP << 8) |
1640 *ptr++ = htonl(tstamp);
1641 *ptr++ = htonl(tp->ts_recent);
1643 if (tp->eff_sacks) {
1644 struct tcp_sack_block *sp = tp->dsack ? tp->duplicate_sack : tp->selective_acks;
1647 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) |
1648 (TCPOPT_NOP << 16) |
1649 (TCPOPT_SACK << 8) |
1650 (TCPOLEN_SACK_BASE +
1651 (tp->eff_sacks * TCPOLEN_SACK_PERBLOCK)));
1652 for(this_sack = 0; this_sack < tp->eff_sacks; this_sack++) {
1653 *ptr++ = htonl(sp[this_sack].start_seq);
1654 *ptr++ = htonl(sp[this_sack].end_seq);
1663 /* Construct a tcp options header for a SYN or SYN_ACK packet.
1664 * If this is every changed make sure to change the definition of
1665 * MAX_SYN_SIZE to match the new maximum number of options that you
1668 static inline void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack,
1669 int offer_wscale, int wscale, __u32 tstamp, __u32 ts_recent)
1671 /* We always get an MSS option.
1672 * The option bytes which will be seen in normal data
1673 * packets should timestamps be used, must be in the MSS
1674 * advertised. But we subtract them from tp->mss_cache so
1675 * that calculations in tcp_sendmsg are simpler etc.
1676 * So account for this fact here if necessary. If we
1677 * don't do this correctly, as a receiver we won't
1678 * recognize data packets as being full sized when we
1679 * should, and thus we won't abide by the delayed ACK
1681 * SACKs don't matter, we never delay an ACK when we
1682 * have any of those going out.
1684 *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss);
1687 *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) |
1688 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1690 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1691 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1692 *ptr++ = htonl(tstamp); /* TSVAL */
1693 *ptr++ = htonl(ts_recent); /* TSECR */
1695 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1696 (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM);
1698 *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale));
1701 /* Determine a window scaling and initial window to offer.
1702 * Based on the assumption that the given amount of space
1703 * will be offered. Store the results in the tp structure.
1704 * NOTE: for smooth operation initial space offering should
1705 * be a multiple of mss if possible. We assume here that mss >= 1.
1706 * This MUST be enforced by all callers.
1708 static inline void tcp_select_initial_window(int __space, __u32 mss,
1710 __u32 *window_clamp,
1714 unsigned int space = (__space < 0 ? 0 : __space);
1716 /* If no clamp set the clamp to the max possible scaled window */
1717 if (*window_clamp == 0)
1718 (*window_clamp) = (65535 << 14);
1719 space = min(*window_clamp, space);
1721 /* Quantize space offering to a multiple of mss if possible. */
1723 space = (space / mss) * mss;
1725 /* NOTE: offering an initial window larger than 32767
1726 * will break some buggy TCP stacks. We try to be nice.
1727 * If we are not window scaling, then this truncates
1728 * our initial window offering to 32k. There should also
1729 * be a sysctl option to stop being nice.
1731 (*rcv_wnd) = min(space, MAX_TCP_WINDOW);
1734 /* See RFC1323 for an explanation of the limit to 14 */
1735 while (space > 65535 && (*rcv_wscale) < 14) {
1739 if (*rcv_wscale && sysctl_tcp_app_win && space>=mss &&
1740 space - max((space>>sysctl_tcp_app_win), mss>>*rcv_wscale) < 65536/2)
1743 *rcv_wscale = max((__u8)sysctl_tcp_default_win_scale,
1747 /* Set initial window to value enough for senders,
1748 * following RFC1414. Senders, not following this RFC,
1749 * will be satisfied with 2.
1751 if (mss > (1<<*rcv_wscale)) {
1755 else if (mss > 1460)
1757 if (*rcv_wnd > init_cwnd*mss)
1758 *rcv_wnd = init_cwnd*mss;
1760 /* Set the clamp no higher than max representable value */
1761 (*window_clamp) = min(65535U << (*rcv_wscale), *window_clamp);
1764 static inline int tcp_win_from_space(int space)
1766 return sysctl_tcp_adv_win_scale<=0 ?
1767 (space>>(-sysctl_tcp_adv_win_scale)) :
1768 space - (space>>sysctl_tcp_adv_win_scale);
1771 /* Note: caller must be prepared to deal with negative returns */
1772 static inline int tcp_space(struct sock *sk)
1774 return tcp_win_from_space(sk->sk_rcvbuf -
1775 atomic_read(&sk->sk_rmem_alloc));
1778 static inline int tcp_full_space( struct sock *sk)
1780 return tcp_win_from_space(sk->sk_rcvbuf);
1783 struct tcp_listen_opt
1785 u8 max_qlen_log; /* log_2 of maximal queued SYNs */
1787 #ifdef CONFIG_ACCEPT_QUEUES
1788 int qlen_young[NUM_ACCEPT_QUEUES];
1794 struct open_request *syn_table[TCP_SYNQ_HSIZE];
1797 #ifdef CONFIG_ACCEPT_QUEUES
1798 static inline void sk_acceptq_removed(struct sock *sk, int class)
1800 tcp_sk(sk)->acceptq[class].aq_backlog--;
1803 static inline void sk_acceptq_added(struct sock *sk, int class)
1805 tcp_sk(sk)->acceptq[class].aq_backlog++;
1808 static inline int sk_acceptq_is_full(struct sock *sk, int class)
1810 return tcp_sk(sk)->acceptq[class].aq_backlog >
1811 sk->sk_max_ack_backlog;
1814 static inline void tcp_set_acceptq(struct tcp_opt *tp, struct open_request *req)
1816 int class = req->acceptq_class;
1819 if (!tp->acceptq[class].aq_ratio) {
1820 req->acceptq_class = 0;
1824 tp->acceptq[class].aq_qcount++;
1825 req->acceptq_time_stamp = jiffies;
1827 if (tp->acceptq[class].aq_tail) {
1828 req->dl_next = tp->acceptq[class].aq_tail->dl_next;
1829 tp->acceptq[class].aq_tail->dl_next = req;
1830 tp->acceptq[class].aq_tail = req;
1831 } else { /* if first request in the class */
1832 tp->acceptq[class].aq_head = req;
1833 tp->acceptq[class].aq_tail = req;
1835 prev_class = class - 1;
1836 while (prev_class >= 0) {
1837 if (tp->acceptq[prev_class].aq_tail)
1841 if (prev_class < 0) {
1842 req->dl_next = tp->accept_queue;
1843 tp->accept_queue = req;
1846 req->dl_next = tp->acceptq[prev_class].aq_tail->dl_next;
1847 tp->acceptq[prev_class].aq_tail->dl_next = req;
1851 static inline void tcp_acceptq_queue(struct sock *sk, struct open_request *req,
1854 tcp_set_acceptq(tcp_sk(sk),req);
1856 sk_acceptq_added(sk,req->acceptq_class);
1860 static inline void tcp_acceptq_queue(struct sock *sk, struct open_request *req,
1863 struct tcp_opt *tp = tcp_sk(sk);
1866 sk_acceptq_added(sk);
1868 if (!tp->accept_queue_tail) {
1869 tp->accept_queue = req;
1871 tp->accept_queue_tail->dl_next = req;
1873 tp->accept_queue_tail = req;
1874 req->dl_next = NULL;
1880 #ifdef CONFIG_ACCEPT_QUEUES
1882 tcp_synq_removed(struct sock *sk, struct open_request *req)
1884 struct tcp_listen_opt *lopt = tcp_sk(sk)->listen_opt;
1886 if (--lopt->qlen == 0)
1887 tcp_delete_keepalive_timer(sk);
1888 if (req->retrans == 0)
1889 lopt->qlen_young[req->acceptq_class]--;
1892 static inline void tcp_synq_added(struct sock *sk, struct open_request *req)
1894 struct tcp_listen_opt *lopt = tcp_sk(sk)->listen_opt;
1896 if (lopt->qlen++ == 0)
1897 tcp_reset_keepalive_timer(sk, TCP_TIMEOUT_INIT);
1898 lopt->qlen_young[req->acceptq_class]++;
1901 static inline int tcp_synq_len(struct sock *sk)
1903 return tcp_sk(sk)->listen_opt->qlen;
1906 static inline int tcp_synq_young(struct sock *sk, int class)
1908 return tcp_sk(sk)->listen_opt->qlen_young[class];
1914 tcp_synq_removed(struct sock *sk, struct open_request *req)
1916 struct tcp_listen_opt *lopt = tcp_sk(sk)->listen_opt;
1918 if (--lopt->qlen == 0)
1919 tcp_delete_keepalive_timer(sk);
1920 if (req->retrans == 0)
1924 static inline void tcp_synq_added(struct sock *sk)
1926 struct tcp_listen_opt *lopt = tcp_sk(sk)->listen_opt;
1928 if (lopt->qlen++ == 0)
1929 tcp_reset_keepalive_timer(sk, TCP_TIMEOUT_INIT);
1933 static inline int tcp_synq_len(struct sock *sk)
1935 return tcp_sk(sk)->listen_opt->qlen;
1938 static inline int tcp_synq_young(struct sock *sk)
1940 return tcp_sk(sk)->listen_opt->qlen_young;
1944 static inline int tcp_synq_is_full(struct sock *sk)
1946 return tcp_synq_len(sk) >> tcp_sk(sk)->listen_opt->max_qlen_log;
1949 static inline void tcp_synq_unlink(struct tcp_opt *tp, struct open_request *req,
1950 struct open_request **prev)
1952 write_lock(&tp->syn_wait_lock);
1953 *prev = req->dl_next;
1954 write_unlock(&tp->syn_wait_lock);
1957 static inline void tcp_synq_drop(struct sock *sk, struct open_request *req,
1958 struct open_request **prev)
1960 tcp_synq_unlink(tcp_sk(sk), req, prev);
1961 tcp_synq_removed(sk, req);
1962 tcp_openreq_free(req);
1965 static __inline__ void tcp_openreq_init(struct open_request *req,
1967 struct sk_buff *skb)
1969 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */
1970 req->rcv_isn = TCP_SKB_CB(skb)->seq;
1971 req->mss = tp->mss_clamp;
1972 req->ts_recent = tp->saw_tstamp ? tp->rcv_tsval : 0;
1973 req->tstamp_ok = tp->tstamp_ok;
1974 req->sack_ok = tp->sack_ok;
1975 req->snd_wscale = tp->snd_wscale;
1976 req->wscale_ok = tp->wscale_ok;
1979 req->rmt_port = skb->h.th->source;
1982 extern void tcp_enter_memory_pressure(void);
1984 extern void tcp_listen_wlock(void);
1986 /* - We may sleep inside this lock.
1987 * - If sleeping is not required (or called from BH),
1988 * use plain read_(un)lock(&tcp_lhash_lock).
1991 static inline void tcp_listen_lock(void)
1993 /* read_lock synchronizes to candidates to writers */
1994 read_lock(&tcp_lhash_lock);
1995 atomic_inc(&tcp_lhash_users);
1996 read_unlock(&tcp_lhash_lock);
1999 static inline void tcp_listen_unlock(void)
2001 if (atomic_dec_and_test(&tcp_lhash_users))
2002 wake_up(&tcp_lhash_wait);
2005 static inline int keepalive_intvl_when(struct tcp_opt *tp)
2007 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl;
2010 static inline int keepalive_time_when(struct tcp_opt *tp)
2012 return tp->keepalive_time ? : sysctl_tcp_keepalive_time;
2015 static inline int tcp_fin_time(struct tcp_opt *tp)
2017 int fin_timeout = tp->linger2 ? : sysctl_tcp_fin_timeout;
2019 if (fin_timeout < (tp->rto<<2) - (tp->rto>>1))
2020 fin_timeout = (tp->rto<<2) - (tp->rto>>1);
2025 static inline int tcp_paws_check(struct tcp_opt *tp, int rst)
2027 if ((s32)(tp->rcv_tsval - tp->ts_recent) >= 0)
2029 if (xtime.tv_sec >= tp->ts_recent_stamp + TCP_PAWS_24DAYS)
2032 /* RST segments are not recommended to carry timestamp,
2033 and, if they do, it is recommended to ignore PAWS because
2034 "their cleanup function should take precedence over timestamps."
2035 Certainly, it is mistake. It is necessary to understand the reasons
2036 of this constraint to relax it: if peer reboots, clock may go
2037 out-of-sync and half-open connections will not be reset.
2038 Actually, the problem would be not existing if all
2039 the implementations followed draft about maintaining clock
2040 via reboots. Linux-2.2 DOES NOT!
2042 However, we can relax time bounds for RST segments to MSL.
2044 if (rst && xtime.tv_sec >= tp->ts_recent_stamp + TCP_PAWS_MSL)
2049 static inline void tcp_v4_setup_caps(struct sock *sk, struct dst_entry *dst)
2051 sk->sk_route_caps = dst->dev->features;
2052 if (sk->sk_route_caps & NETIF_F_TSO) {
2053 if (sk->sk_no_largesend || dst->header_len)
2054 sk->sk_route_caps &= ~NETIF_F_TSO;
2058 #define TCP_CHECK_TIMER(sk) do { } while (0)
2060 static inline int tcp_use_frto(const struct sock *sk)
2062 const struct tcp_opt *tp = tcp_sk(sk);
2064 /* F-RTO must be activated in sysctl and there must be some
2065 * unsent new data, and the advertised window should allow
2068 return (sysctl_tcp_frto && sk->sk_send_head &&
2069 !after(TCP_SKB_CB(sk->sk_send_head)->end_seq,
2070 tp->snd_una + tp->snd_wnd));
2073 static inline void tcp_mib_init(void)
2076 TCP_ADD_STATS_USER(TcpRtoAlgorithm, 1);
2077 TCP_ADD_STATS_USER(TcpRtoMin, TCP_RTO_MIN*1000/HZ);
2078 TCP_ADD_STATS_USER(TcpRtoMax, TCP_RTO_MAX*1000/HZ);
2079 TCP_ADD_STATS_USER(TcpMaxConn, -1);
2083 enum tcp_seq_states {
2084 TCP_SEQ_STATE_LISTENING,
2085 TCP_SEQ_STATE_OPENREQ,
2086 TCP_SEQ_STATE_ESTABLISHED,
2087 TCP_SEQ_STATE_TIME_WAIT,
2090 struct tcp_seq_afinfo {
2091 struct module *owner;
2094 int (*seq_show) (struct seq_file *m, void *v);
2095 struct file_operations *seq_fops;
2098 struct tcp_iter_state {
2100 enum tcp_seq_states state;
2101 struct sock *syn_wait_sk;
2102 int bucket, sbucket, num, uid;
2103 struct seq_operations seq_ops;
2106 extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo);
2107 extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo);
2109 /* TCP Westwood functions and constants */
2111 #define TCP_WESTWOOD_INIT_RTT (20*HZ) /* maybe too conservative?! */
2112 #define TCP_WESTWOOD_RTT_MIN (HZ/20) /* 50ms */
2114 static inline void tcp_westwood_update_rtt(struct tcp_opt *tp, __u32 rtt_seq)
2116 if (sysctl_tcp_westwood)
2117 tp->westwood.rtt = rtt_seq;
2120 void __tcp_westwood_fast_bw(struct sock *, struct sk_buff *);
2121 void __tcp_westwood_slow_bw(struct sock *, struct sk_buff *);
2123 static inline void tcp_westwood_fast_bw(struct sock *sk, struct sk_buff *skb)
2125 if (sysctl_tcp_westwood)
2126 __tcp_westwood_fast_bw(sk, skb);
2129 static inline void tcp_westwood_slow_bw(struct sock *sk, struct sk_buff *skb)
2131 if (sysctl_tcp_westwood)
2132 __tcp_westwood_slow_bw(sk, skb);
2135 static inline __u32 __tcp_westwood_bw_rttmin(const struct tcp_opt *tp)
2137 return max((tp->westwood.bw_est) * (tp->westwood.rtt_min) /
2138 (__u32) (tp->mss_cache),
2142 static inline __u32 tcp_westwood_bw_rttmin(const struct tcp_opt *tp)
2144 return sysctl_tcp_westwood ? __tcp_westwood_bw_rttmin(tp) : 0;
2147 static inline int tcp_westwood_ssthresh(struct tcp_opt *tp)
2151 if (sysctl_tcp_westwood) {
2152 ssthresh = __tcp_westwood_bw_rttmin(tp);
2154 tp->snd_ssthresh = ssthresh;
2157 return (ssthresh != 0);
2160 static inline int tcp_westwood_cwnd(struct tcp_opt *tp)
2164 if (sysctl_tcp_westwood) {
2165 cwnd = __tcp_westwood_bw_rttmin(tp);
2167 tp->snd_cwnd = cwnd;