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 * Implementation of the Transmission Control Protocol(TCP).
8 * Version: $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $
10 * Authors: Ross Biro, <bir7@leland.Stanford.Edu>
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Mark Evans, <evansmp@uhura.aston.ac.uk>
13 * Corey Minyard <wf-rch!minyard@relay.EU.net>
14 * Florian La Roche, <flla@stud.uni-sb.de>
15 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
16 * Linus Torvalds, <torvalds@cs.helsinki.fi>
17 * Alan Cox, <gw4pts@gw4pts.ampr.org>
18 * Matthew Dillon, <dillon@apollo.west.oic.com>
19 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
20 * Jorge Cwik, <jorge@laser.satlink.net>
23 * Alan Cox : Numerous verify_area() calls
24 * Alan Cox : Set the ACK bit on a reset
25 * Alan Cox : Stopped it crashing if it closed while
26 * sk->inuse=1 and was trying to connect
28 * Alan Cox : All icmp error handling was broken
29 * pointers passed where wrong and the
30 * socket was looked up backwards. Nobody
31 * tested any icmp error code obviously.
32 * Alan Cox : tcp_err() now handled properly. It
33 * wakes people on errors. poll
34 * behaves and the icmp error race
35 * has gone by moving it into sock.c
36 * Alan Cox : tcp_send_reset() fixed to work for
37 * everything not just packets for
39 * Alan Cox : tcp option processing.
40 * Alan Cox : Reset tweaked (still not 100%) [Had
42 * Herp Rosmanith : More reset fixes
43 * Alan Cox : No longer acks invalid rst frames.
44 * Acking any kind of RST is right out.
45 * Alan Cox : Sets an ignore me flag on an rst
46 * receive otherwise odd bits of prattle
48 * Alan Cox : Fixed another acking RST frame bug.
49 * Should stop LAN workplace lockups.
50 * Alan Cox : Some tidyups using the new skb list
52 * Alan Cox : sk->keepopen now seems to work
53 * Alan Cox : Pulls options out correctly on accepts
54 * Alan Cox : Fixed assorted sk->rqueue->next errors
55 * Alan Cox : PSH doesn't end a TCP read. Switched a
57 * Alan Cox : Tidied tcp_data to avoid a potential
59 * Alan Cox : Added some better commenting, as the
60 * tcp is hard to follow
61 * Alan Cox : Removed incorrect check for 20 * psh
62 * Michael O'Reilly : ack < copied bug fix.
63 * Johannes Stille : Misc tcp fixes (not all in yet).
64 * Alan Cox : FIN with no memory -> CRASH
65 * Alan Cox : Added socket option proto entries.
66 * Also added awareness of them to accept.
67 * Alan Cox : Added TCP options (SOL_TCP)
68 * Alan Cox : Switched wakeup calls to callbacks,
69 * so the kernel can layer network
71 * Alan Cox : Use ip_tos/ip_ttl settings.
72 * Alan Cox : Handle FIN (more) properly (we hope).
73 * Alan Cox : RST frames sent on unsynchronised
75 * Alan Cox : Put in missing check for SYN bit.
76 * Alan Cox : Added tcp_select_window() aka NET2E
77 * window non shrink trick.
78 * Alan Cox : Added a couple of small NET2E timer
80 * Charles Hedrick : TCP fixes
81 * Toomas Tamm : TCP window fixes
82 * Alan Cox : Small URG fix to rlogin ^C ack fight
83 * Charles Hedrick : Rewrote most of it to actually work
84 * Linus : Rewrote tcp_read() and URG handling
86 * Gerhard Koerting: Fixed some missing timer handling
87 * Matthew Dillon : Reworked TCP machine states as per RFC
88 * Gerhard Koerting: PC/TCP workarounds
89 * Adam Caldwell : Assorted timer/timing errors
90 * Matthew Dillon : Fixed another RST bug
91 * Alan Cox : Move to kernel side addressing changes.
92 * Alan Cox : Beginning work on TCP fastpathing
94 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
95 * Alan Cox : TCP fast path debugging
96 * Alan Cox : Window clamping
97 * Michael Riepe : Bug in tcp_check()
98 * Matt Dillon : More TCP improvements and RST bug fixes
99 * Matt Dillon : Yet more small nasties remove from the
100 * TCP code (Be very nice to this man if
101 * tcp finally works 100%) 8)
102 * Alan Cox : BSD accept semantics.
103 * Alan Cox : Reset on closedown bug.
104 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
105 * Michael Pall : Handle poll() after URG properly in
107 * Michael Pall : Undo the last fix in tcp_read_urg()
108 * (multi URG PUSH broke rlogin).
109 * Michael Pall : Fix the multi URG PUSH problem in
110 * tcp_readable(), poll() after URG
112 * Michael Pall : recv(...,MSG_OOB) never blocks in the
114 * Alan Cox : Changed the semantics of sk->socket to
115 * fix a race and a signal problem with
116 * accept() and async I/O.
117 * Alan Cox : Relaxed the rules on tcp_sendto().
118 * Yury Shevchuk : Really fixed accept() blocking problem.
119 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
120 * clients/servers which listen in on
122 * Alan Cox : Cleaned the above up and shrank it to
123 * a sensible code size.
124 * Alan Cox : Self connect lockup fix.
125 * Alan Cox : No connect to multicast.
126 * Ross Biro : Close unaccepted children on master
128 * Alan Cox : Reset tracing code.
129 * Alan Cox : Spurious resets on shutdown.
130 * Alan Cox : Giant 15 minute/60 second timer error
131 * Alan Cox : Small whoops in polling before an
133 * Alan Cox : Kept the state trace facility since
134 * it's handy for debugging.
135 * Alan Cox : More reset handler fixes.
136 * Alan Cox : Started rewriting the code based on
137 * the RFC's for other useful protocol
138 * references see: Comer, KA9Q NOS, and
139 * for a reference on the difference
140 * between specifications and how BSD
141 * works see the 4.4lite source.
142 * A.N.Kuznetsov : Don't time wait on completion of tidy
144 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
145 * Linus Torvalds : Fixed BSD port reuse to work first syn
146 * Alan Cox : Reimplemented timers as per the RFC
147 * and using multiple timers for sanity.
148 * Alan Cox : Small bug fixes, and a lot of new
150 * Alan Cox : Fixed dual reader crash by locking
151 * the buffers (much like datagram.c)
152 * Alan Cox : Fixed stuck sockets in probe. A probe
153 * now gets fed up of retrying without
154 * (even a no space) answer.
155 * Alan Cox : Extracted closing code better
156 * Alan Cox : Fixed the closing state machine to
158 * Alan Cox : More 'per spec' fixes.
159 * Jorge Cwik : Even faster checksumming.
160 * Alan Cox : tcp_data() doesn't ack illegal PSH
161 * only frames. At least one pc tcp stack
163 * Alan Cox : Cache last socket.
164 * Alan Cox : Per route irtt.
165 * Matt Day : poll()->select() match BSD precisely on error
166 * Alan Cox : New buffers
167 * Marc Tamsky : Various sk->prot->retransmits and
168 * sk->retransmits misupdating fixed.
169 * Fixed tcp_write_timeout: stuck close,
170 * and TCP syn retries gets used now.
171 * Mark Yarvis : In tcp_read_wakeup(), don't send an
172 * ack if state is TCP_CLOSED.
173 * Alan Cox : Look up device on a retransmit - routes may
174 * change. Doesn't yet cope with MSS shrink right
176 * Marc Tamsky : Closing in closing fixes.
177 * Mike Shaver : RFC1122 verifications.
178 * Alan Cox : rcv_saddr errors.
179 * Alan Cox : Block double connect().
180 * Alan Cox : Small hooks for enSKIP.
181 * Alexey Kuznetsov: Path MTU discovery.
182 * Alan Cox : Support soft errors.
183 * Alan Cox : Fix MTU discovery pathological case
184 * when the remote claims no mtu!
185 * Marc Tamsky : TCP_CLOSE fix.
186 * Colin (G3TNE) : Send a reset on syn ack replies in
187 * window but wrong (fixes NT lpd problems)
188 * Pedro Roque : Better TCP window handling, delayed ack.
189 * Joerg Reuter : No modification of locked buffers in
190 * tcp_do_retransmit()
191 * Eric Schenk : Changed receiver side silly window
192 * avoidance algorithm to BSD style
193 * algorithm. This doubles throughput
194 * against machines running Solaris,
195 * and seems to result in general
197 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
198 * Willy Konynenberg : Transparent proxying support.
199 * Mike McLagan : Routing by source
200 * Keith Owens : Do proper merging with partial SKB's in
201 * tcp_do_sendmsg to avoid burstiness.
202 * Eric Schenk : Fix fast close down bug with
203 * shutdown() followed by close().
204 * Andi Kleen : Make poll agree with SIGIO
205 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
206 * lingertime == 0 (RFC 793 ABORT Call)
207 * Hirokazu Takahashi : Use copy_from_user() instead of
208 * csum_and_copy_from_user() if possible.
210 * This program is free software; you can redistribute it and/or
211 * modify it under the terms of the GNU General Public License
212 * as published by the Free Software Foundation; either version
213 * 2 of the License, or(at your option) any later version.
215 * Description of States:
217 * TCP_SYN_SENT sent a connection request, waiting for ack
219 * TCP_SYN_RECV received a connection request, sent ack,
220 * waiting for final ack in three-way handshake.
222 * TCP_ESTABLISHED connection established
224 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
225 * transmission of remaining buffered data
227 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
230 * TCP_CLOSING both sides have shutdown but we still have
231 * data we have to finish sending
233 * TCP_TIME_WAIT timeout to catch resent junk before entering
234 * closed, can only be entered from FIN_WAIT2
235 * or CLOSING. Required because the other end
236 * may not have gotten our last ACK causing it
237 * to retransmit the data packet (which we ignore)
239 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
240 * us to finish writing our data and to shutdown
241 * (we have to close() to move on to LAST_ACK)
243 * TCP_LAST_ACK out side has shutdown after remote has
244 * shutdown. There may still be data in our
245 * buffer that we have to finish sending
247 * TCP_CLOSE socket is finished
250 #include <linux/config.h>
251 #include <linux/module.h>
252 #include <linux/types.h>
253 #include <linux/fcntl.h>
254 #include <linux/poll.h>
255 #include <linux/init.h>
256 #include <linux/smp_lock.h>
257 #include <linux/fs.h>
258 #include <linux/random.h>
261 #include <linux/ckrm.h>
264 #include <net/icmp.h>
266 #include <net/xfrm.h>
270 #include <asm/uaccess.h>
271 #include <asm/ioctls.h>
273 int sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
275 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics);
277 kmem_cache_t *tcp_openreq_cachep;
278 kmem_cache_t *tcp_bucket_cachep;
279 kmem_cache_t *tcp_timewait_cachep;
281 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
283 int sysctl_tcp_mem[3];
284 int sysctl_tcp_wmem[3] = { 4 * 1024, 16 * 1024, 128 * 1024 };
285 int sysctl_tcp_rmem[3] = { 4 * 1024, 87380, 87380 * 2 };
287 EXPORT_SYMBOL(sysctl_tcp_mem);
288 EXPORT_SYMBOL(sysctl_tcp_rmem);
289 EXPORT_SYMBOL(sysctl_tcp_wmem);
291 atomic_t tcp_memory_allocated; /* Current allocated memory. */
292 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
294 EXPORT_SYMBOL(tcp_memory_allocated);
295 EXPORT_SYMBOL(tcp_sockets_allocated);
298 * Pressure flag: try to collapse.
299 * Technical note: it is used by multiple contexts non atomically.
300 * All the sk_stream_mem_schedule() is of this nature: accounting
301 * is strict, actions are advisory and have some latency.
303 int tcp_memory_pressure;
305 EXPORT_SYMBOL(tcp_memory_pressure);
307 void tcp_enter_memory_pressure(void)
309 if (!tcp_memory_pressure) {
310 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
311 tcp_memory_pressure = 1;
315 EXPORT_SYMBOL(tcp_enter_memory_pressure);
318 * LISTEN is a special case for poll..
320 static __inline__ unsigned int tcp_listen_poll(struct sock *sk,
323 return tcp_sk(sk)->accept_queue ? (POLLIN | POLLRDNORM) : 0;
327 * Wait for a TCP event.
329 * Note that we don't need to lock the socket, as the upper poll layers
330 * take care of normal races (between the test and the event) and we don't
331 * go look at any of the socket buffers directly.
333 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
336 struct sock *sk = sock->sk;
337 struct tcp_opt *tp = tcp_sk(sk);
339 poll_wait(file, sk->sk_sleep, wait);
340 if (sk->sk_state == TCP_LISTEN)
341 return tcp_listen_poll(sk, wait);
343 /* Socket is not locked. We are protected from async events
344 by poll logic and correct handling of state changes
345 made by another threads is impossible in any case.
353 * POLLHUP is certainly not done right. But poll() doesn't
354 * have a notion of HUP in just one direction, and for a
355 * socket the read side is more interesting.
357 * Some poll() documentation says that POLLHUP is incompatible
358 * with the POLLOUT/POLLWR flags, so somebody should check this
359 * all. But careful, it tends to be safer to return too many
360 * bits than too few, and you can easily break real applications
361 * if you don't tell them that something has hung up!
365 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
366 * our fs/select.c). It means that after we received EOF,
367 * poll always returns immediately, making impossible poll() on write()
368 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
369 * if and only if shutdown has been made in both directions.
370 * Actually, it is interesting to look how Solaris and DUX
371 * solve this dilemma. I would prefer, if PULLHUP were maskable,
372 * then we could set it on SND_SHUTDOWN. BTW examples given
373 * in Stevens' books assume exactly this behaviour, it explains
374 * why PULLHUP is incompatible with POLLOUT. --ANK
376 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
377 * blocking on fresh not-connected or disconnected socket. --ANK
379 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
381 if (sk->sk_shutdown & RCV_SHUTDOWN)
382 mask |= POLLIN | POLLRDNORM;
385 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
386 /* Potential race condition. If read of tp below will
387 * escape above sk->sk_state, we can be illegally awaken
388 * in SYN_* states. */
389 if ((tp->rcv_nxt != tp->copied_seq) &&
390 (tp->urg_seq != tp->copied_seq ||
391 tp->rcv_nxt != tp->copied_seq + 1 ||
392 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
393 mask |= POLLIN | POLLRDNORM;
395 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
396 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
397 mask |= POLLOUT | POLLWRNORM;
398 } else { /* send SIGIO later */
399 set_bit(SOCK_ASYNC_NOSPACE,
400 &sk->sk_socket->flags);
401 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
403 /* Race breaker. If space is freed after
404 * wspace test but before the flags are set,
405 * IO signal will be lost.
407 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
408 mask |= POLLOUT | POLLWRNORM;
412 if (tp->urg_data & TCP_URG_VALID)
418 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
420 struct tcp_opt *tp = tcp_sk(sk);
425 if (sk->sk_state == TCP_LISTEN)
429 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
431 else if (sock_flag(sk, SOCK_URGINLINE) ||
433 before(tp->urg_seq, tp->copied_seq) ||
434 !before(tp->urg_seq, tp->rcv_nxt)) {
435 answ = tp->rcv_nxt - tp->copied_seq;
437 /* Subtract 1, if FIN is in queue. */
438 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
440 ((struct sk_buff *)sk->sk_receive_queue.prev)->h.th->fin;
442 answ = tp->urg_seq - tp->copied_seq;
446 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
449 if (sk->sk_state == TCP_LISTEN)
452 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
455 answ = tp->write_seq - tp->snd_una;
461 return put_user(answ, (int __user *)arg);
465 int tcp_listen_start(struct sock *sk)
467 #ifdef CONFIG_ACCEPT_QUEUES
470 struct inet_opt *inet = inet_sk(sk);
471 struct tcp_opt *tp = tcp_sk(sk);
472 struct tcp_listen_opt *lopt;
474 sk->sk_max_ack_backlog = 0;
475 sk->sk_ack_backlog = 0;
476 #ifdef CONFIG_ACCEPT_QUEUES
477 tp->accept_queue = NULL;
479 tp->accept_queue = tp->accept_queue_tail = NULL;
481 tp->syn_wait_lock = RW_LOCK_UNLOCKED;
484 lopt = kmalloc(sizeof(struct tcp_listen_opt), GFP_KERNEL);
488 memset(lopt, 0, sizeof(struct tcp_listen_opt));
489 for (lopt->max_qlen_log = 6; ; lopt->max_qlen_log++)
490 if ((1 << lopt->max_qlen_log) >= sysctl_max_syn_backlog)
492 get_random_bytes(&lopt->hash_rnd, 4);
494 #ifdef CONFIG_ACCEPT_QUEUES
496 for (i=0; i < NUM_ACCEPT_QUEUES; i++) {
497 tp->acceptq[i].aq_tail = NULL;
498 tp->acceptq[i].aq_head = NULL;
499 tp->acceptq[i].aq_wait_time = 0;
500 tp->acceptq[i].aq_qcount = 0;
501 tp->acceptq[i].aq_count = 0;
503 tp->acceptq[i].aq_ratio = 1;
506 tp->acceptq[i].aq_ratio = 0;
511 write_lock_bh(&tp->syn_wait_lock);
512 tp->listen_opt = lopt;
513 write_unlock_bh(&tp->syn_wait_lock);
515 /* There is race window here: we announce ourselves listening,
516 * but this transition is still not validated by get_port().
517 * It is OK, because this socket enters to hash table only
518 * after validation is complete.
520 sk->sk_state = TCP_LISTEN;
521 if (!sk->sk_prot->get_port(sk, inet->num)) {
522 inet->sport = htons(inet->num);
525 sk->sk_prot->hash(sk);
528 ckrm_cb_listen_start(sk);
534 sk->sk_state = TCP_CLOSE;
535 write_lock_bh(&tp->syn_wait_lock);
536 tp->listen_opt = NULL;
537 write_unlock_bh(&tp->syn_wait_lock);
543 * This routine closes sockets which have been at least partially
544 * opened, but not yet accepted.
547 static void tcp_listen_stop (struct sock *sk)
549 struct tcp_opt *tp = tcp_sk(sk);
550 struct tcp_listen_opt *lopt = tp->listen_opt;
551 struct open_request *acc_req = tp->accept_queue;
552 struct open_request *req;
555 tcp_delete_keepalive_timer(sk);
557 /* make all the listen_opt local to us */
558 write_lock_bh(&tp->syn_wait_lock);
559 tp->listen_opt = NULL;
560 write_unlock_bh(&tp->syn_wait_lock);
563 ckrm_cb_listen_stop(sk);
566 #ifdef CONFIG_ACCEPT_QUEUES
567 for (i = 0; i < NUM_ACCEPT_QUEUES; i++)
568 tp->acceptq[i].aq_head = tp->acceptq[i].aq_tail = NULL;
570 tp->accept_queue_tail = NULL;
572 tp->accept_queue = NULL;
575 for (i = 0; i < TCP_SYNQ_HSIZE; i++) {
576 while ((req = lopt->syn_table[i]) != NULL) {
577 lopt->syn_table[i] = req->dl_next;
579 tcp_openreq_free(req);
581 /* Following specs, it would be better either to send FIN
582 * (and enter FIN-WAIT-1, it is normal close)
583 * or to send active reset (abort).
584 * Certainly, it is pretty dangerous while synflood, but it is
585 * bad justification for our negligence 8)
586 * To be honest, we are not able to make either
587 * of the variants now. --ANK
592 BUG_TRAP(!lopt->qlen);
596 while ((req = acc_req) != NULL) {
597 struct sock *child = req->sk;
599 acc_req = req->dl_next;
603 BUG_TRAP(!sock_owned_by_user(child));
606 tcp_disconnect(child, O_NONBLOCK);
610 atomic_inc(&tcp_orphan_count);
612 tcp_destroy_sock(child);
614 bh_unlock_sock(child);
618 #ifdef CONFIG_ACCEPT_QUEUES
619 sk_acceptq_removed(sk, req->acceptq_class);
621 sk_acceptq_removed(sk);
623 tcp_openreq_fastfree(req);
625 BUG_TRAP(!sk->sk_ack_backlog);
628 static inline void tcp_mark_push(struct tcp_opt *tp, struct sk_buff *skb)
630 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
631 tp->pushed_seq = tp->write_seq;
634 static inline int forced_push(struct tcp_opt *tp)
636 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
639 static inline void skb_entail(struct sock *sk, struct tcp_opt *tp,
643 TCP_SKB_CB(skb)->seq = tp->write_seq;
644 TCP_SKB_CB(skb)->end_seq = tp->write_seq;
645 TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
646 TCP_SKB_CB(skb)->sacked = 0;
647 __skb_queue_tail(&sk->sk_write_queue, skb);
648 sk_charge_skb(sk, skb);
649 if (!sk->sk_send_head)
650 sk->sk_send_head = skb;
651 else if (tp->nonagle&TCP_NAGLE_PUSH)
652 tp->nonagle &= ~TCP_NAGLE_PUSH;
655 static inline void tcp_mark_urg(struct tcp_opt *tp, int flags,
658 if (flags & MSG_OOB) {
660 tp->snd_up = tp->write_seq;
661 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
665 static inline void tcp_push(struct sock *sk, struct tcp_opt *tp, int flags,
666 int mss_now, int nonagle)
668 if (sk->sk_send_head) {
669 struct sk_buff *skb = sk->sk_write_queue.prev;
670 if (!(flags & MSG_MORE) || forced_push(tp))
671 tcp_mark_push(tp, skb);
672 tcp_mark_urg(tp, flags, skb);
673 __tcp_push_pending_frames(sk, tp, mss_now,
674 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
678 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
679 size_t psize, int flags)
681 struct tcp_opt *tp = tcp_sk(sk);
685 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
687 /* Wait for a connection to finish. */
688 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
689 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
692 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
694 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
698 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
702 struct sk_buff *skb = sk->sk_write_queue.prev;
703 struct page *page = pages[poffset / PAGE_SIZE];
705 int offset = poffset % PAGE_SIZE;
706 int size = min_t(size_t, psize, PAGE_SIZE - offset);
708 if (!sk->sk_send_head || (copy = mss_now - skb->len) <= 0) {
710 if (!sk_stream_memory_free(sk))
711 goto wait_for_sndbuf;
713 skb = sk_stream_alloc_pskb(sk, 0, tp->mss_cache,
716 goto wait_for_memory;
718 skb_entail(sk, tp, skb);
725 i = skb_shinfo(skb)->nr_frags;
726 if (skb_can_coalesce(skb, i, page, offset)) {
727 skb_shinfo(skb)->frags[i - 1].size += copy;
728 } else if (i < MAX_SKB_FRAGS) {
730 skb_fill_page_desc(skb, i, page, offset, copy);
732 tcp_mark_push(tp, skb);
737 skb->data_len += copy;
738 skb->ip_summed = CHECKSUM_HW;
739 tp->write_seq += copy;
740 TCP_SKB_CB(skb)->end_seq += copy;
741 skb_shinfo(skb)->tso_segs = 0;
744 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
748 if (!(psize -= copy))
751 if (skb->len != mss_now || (flags & MSG_OOB))
754 if (forced_push(tp)) {
755 tcp_mark_push(tp, skb);
756 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
757 } else if (skb == sk->sk_send_head)
758 tcp_push_one(sk, mss_now);
762 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
765 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
767 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
770 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
775 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
782 return sk_stream_error(sk, flags, err);
785 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
786 size_t size, int flags)
789 struct sock *sk = sock->sk;
791 #define TCP_ZC_CSUM_FLAGS (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)
793 if (!(sk->sk_route_caps & NETIF_F_SG) ||
794 !(sk->sk_route_caps & TCP_ZC_CSUM_FLAGS))
795 return sock_no_sendpage(sock, page, offset, size, flags);
797 #undef TCP_ZC_CSUM_FLAGS
801 res = do_tcp_sendpages(sk, &page, offset, size, flags);
807 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
808 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
810 static inline int select_size(struct sock *sk, struct tcp_opt *tp)
812 int tmp = tp->mss_cache_std;
814 if (sk->sk_route_caps & NETIF_F_SG) {
815 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
817 if (tmp >= pgbreak &&
818 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
824 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
828 struct tcp_opt *tp = tcp_sk(sk);
838 flags = msg->msg_flags;
839 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
841 /* Wait for a connection to finish. */
842 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
843 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
846 /* This should be in poll */
847 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
849 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
851 /* Ok commence sending. */
852 iovlen = msg->msg_iovlen;
857 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
860 while (--iovlen >= 0) {
861 int seglen = iov->iov_len;
862 unsigned char __user *from = iov->iov_base;
869 skb = sk->sk_write_queue.prev;
871 if (!sk->sk_send_head ||
872 (copy = mss_now - skb->len) <= 0) {
875 /* Allocate new segment. If the interface is SG,
876 * allocate skb fitting to single page.
878 if (!sk_stream_memory_free(sk))
879 goto wait_for_sndbuf;
881 skb = sk_stream_alloc_pskb(sk, select_size(sk, tp),
882 0, sk->sk_allocation);
884 goto wait_for_memory;
887 * Check whether we can use HW checksum.
889 if (sk->sk_route_caps &
890 (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM |
892 skb->ip_summed = CHECKSUM_HW;
894 skb_entail(sk, tp, skb);
898 /* Try to append data to the end of skb. */
902 /* Where to copy to? */
903 if (skb_tailroom(skb) > 0) {
904 /* We have some space in skb head. Superb! */
905 if (copy > skb_tailroom(skb))
906 copy = skb_tailroom(skb);
907 if ((err = skb_add_data(skb, from, copy)) != 0)
911 int i = skb_shinfo(skb)->nr_frags;
912 struct page *page = TCP_PAGE(sk);
913 int off = TCP_OFF(sk);
915 if (skb_can_coalesce(skb, i, page, off) &&
917 /* We can extend the last page
920 } else if (i == MAX_SKB_FRAGS ||
922 !(sk->sk_route_caps & NETIF_F_SG))) {
923 /* Need to add new fragment and cannot
924 * do this because interface is non-SG,
925 * or because all the page slots are
927 tcp_mark_push(tp, skb);
930 /* If page is cached, align
931 * offset to L1 cache boundary
933 off = (off + L1_CACHE_BYTES - 1) &
934 ~(L1_CACHE_BYTES - 1);
935 if (off == PAGE_SIZE) {
937 TCP_PAGE(sk) = page = NULL;
942 /* Allocate new cache page. */
943 if (!(page = sk_stream_alloc_page(sk)))
944 goto wait_for_memory;
948 if (copy > PAGE_SIZE - off)
949 copy = PAGE_SIZE - off;
951 /* Time to copy data. We are close to
953 err = skb_copy_to_page(sk, from, skb, page,
956 /* If this page was new, give it to the
957 * socket so it does not get leaked.
966 /* Update the skb. */
968 skb_shinfo(skb)->frags[i - 1].size +=
971 skb_fill_page_desc(skb, i, page, off, copy);
974 } else if (off + copy < PAGE_SIZE) {
980 TCP_OFF(sk) = off + copy;
984 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
986 tp->write_seq += copy;
987 TCP_SKB_CB(skb)->end_seq += copy;
988 skb_shinfo(skb)->tso_segs = 0;
992 if ((seglen -= copy) == 0 && iovlen == 0)
995 if (skb->len != mss_now || (flags & MSG_OOB))
998 if (forced_push(tp)) {
999 tcp_mark_push(tp, skb);
1000 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
1001 } else if (skb == sk->sk_send_head)
1002 tcp_push_one(sk, mss_now);
1006 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1009 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1011 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1014 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
1020 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
1021 TCP_CHECK_TIMER(sk);
1027 if (sk->sk_send_head == skb)
1028 sk->sk_send_head = NULL;
1029 __skb_unlink(skb, skb->list);
1030 sk_stream_free_skb(sk, skb);
1037 err = sk_stream_error(sk, flags, err);
1038 TCP_CHECK_TIMER(sk);
1044 * Handle reading urgent data. BSD has very simple semantics for
1045 * this, no blocking and very strange errors 8)
1048 static int tcp_recv_urg(struct sock *sk, long timeo,
1049 struct msghdr *msg, int len, int flags,
1052 struct tcp_opt *tp = tcp_sk(sk);
1054 /* No URG data to read. */
1055 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1056 tp->urg_data == TCP_URG_READ)
1057 return -EINVAL; /* Yes this is right ! */
1059 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1062 if (tp->urg_data & TCP_URG_VALID) {
1064 char c = tp->urg_data;
1066 if (!(flags & MSG_PEEK))
1067 tp->urg_data = TCP_URG_READ;
1069 /* Read urgent data. */
1070 msg->msg_flags |= MSG_OOB;
1073 if (!(flags & MSG_TRUNC))
1074 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1077 msg->msg_flags |= MSG_TRUNC;
1079 return err ? -EFAULT : len;
1082 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1085 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1086 * the available implementations agree in this case:
1087 * this call should never block, independent of the
1088 * blocking state of the socket.
1089 * Mike <pall@rz.uni-karlsruhe.de>
1094 /* Clean up the receive buffer for full frames taken by the user,
1095 * then send an ACK if necessary. COPIED is the number of bytes
1096 * tcp_recvmsg has given to the user so far, it speeds up the
1097 * calculation of whether or not we must ACK for the sake of
1100 void cleanup_rbuf(struct sock *sk, int copied)
1102 struct tcp_opt *tp = tcp_sk(sk);
1103 int time_to_ack = 0;
1106 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1108 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
1111 if (tcp_ack_scheduled(tp)) {
1112 /* Delayed ACKs frequently hit locked sockets during bulk
1114 if (tp->ack.blocked ||
1115 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1116 tp->rcv_nxt - tp->rcv_wup > tp->ack.rcv_mss ||
1118 * If this read emptied read buffer, we send ACK, if
1119 * connection is not bidirectional, user drained
1120 * receive buffer and there was a small segment
1123 (copied > 0 && (tp->ack.pending & TCP_ACK_PUSHED) &&
1124 !tp->ack.pingpong && !atomic_read(&sk->sk_rmem_alloc)))
1128 /* We send an ACK if we can now advertise a non-zero window
1129 * which has been raised "significantly".
1131 * Even if window raised up to infinity, do not send window open ACK
1132 * in states, where we will not receive more. It is useless.
1134 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1135 __u32 rcv_window_now = tcp_receive_window(tp);
1137 /* Optimize, __tcp_select_window() is not cheap. */
1138 if (2*rcv_window_now <= tp->window_clamp) {
1139 __u32 new_window = __tcp_select_window(sk);
1141 /* Send ACK now, if this read freed lots of space
1142 * in our buffer. Certainly, new_window is new window.
1143 * We can advertise it now, if it is not less than current one.
1144 * "Lots" means "at least twice" here.
1146 if (new_window && new_window >= 2 * rcv_window_now)
1154 static void tcp_prequeue_process(struct sock *sk)
1156 struct sk_buff *skb;
1157 struct tcp_opt *tp = tcp_sk(sk);
1159 NET_ADD_STATS_USER(LINUX_MIB_TCPPREQUEUED, skb_queue_len(&tp->ucopy.prequeue));
1161 /* RX process wants to run with disabled BHs, though it is not
1164 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1165 sk->sk_backlog_rcv(sk, skb);
1168 /* Clear memory counter. */
1169 tp->ucopy.memory = 0;
1172 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1174 struct sk_buff *skb;
1177 skb_queue_walk(&sk->sk_receive_queue, skb) {
1178 offset = seq - TCP_SKB_CB(skb)->seq;
1181 if (offset < skb->len || skb->h.th->fin) {
1190 * This routine provides an alternative to tcp_recvmsg() for routines
1191 * that would like to handle copying from skbuffs directly in 'sendfile'
1194 * - It is assumed that the socket was locked by the caller.
1195 * - The routine does not block.
1196 * - At present, there is no support for reading OOB data
1197 * or for 'peeking' the socket using this routine
1198 * (although both would be easy to implement).
1200 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1201 sk_read_actor_t recv_actor)
1203 struct sk_buff *skb;
1204 struct tcp_opt *tp = tcp_sk(sk);
1205 u32 seq = tp->copied_seq;
1209 if (sk->sk_state == TCP_LISTEN)
1211 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1212 if (offset < skb->len) {
1215 len = skb->len - offset;
1216 /* Stop reading if we hit a patch of urgent data */
1218 u32 urg_offset = tp->urg_seq - seq;
1219 if (urg_offset < len)
1224 used = recv_actor(desc, skb, offset, len);
1230 if (offset != skb->len)
1233 if (skb->h.th->fin) {
1234 sk_eat_skb(sk, skb);
1238 sk_eat_skb(sk, skb);
1242 tp->copied_seq = seq;
1244 tcp_rcv_space_adjust(sk);
1246 /* Clean up data we have read: This will do ACK frames. */
1248 cleanup_rbuf(sk, copied);
1253 * This routine copies from a sock struct into the user buffer.
1255 * Technical note: in 2.3 we work on _locked_ socket, so that
1256 * tricks with *seq access order and skb->users are not required.
1257 * Probably, code can be easily improved even more.
1260 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1261 size_t len, int nonblock, int flags, int *addr_len)
1263 struct tcp_opt *tp = tcp_sk(sk);
1269 int target; /* Read at least this many bytes */
1271 struct task_struct *user_recv = NULL;
1275 TCP_CHECK_TIMER(sk);
1278 if (sk->sk_state == TCP_LISTEN)
1281 timeo = sock_rcvtimeo(sk, nonblock);
1283 /* Urgent data needs to be handled specially. */
1284 if (flags & MSG_OOB)
1287 seq = &tp->copied_seq;
1288 if (flags & MSG_PEEK) {
1289 peek_seq = tp->copied_seq;
1293 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1296 struct sk_buff *skb;
1299 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1300 if (tp->urg_data && tp->urg_seq == *seq) {
1303 if (signal_pending(current)) {
1304 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1309 /* Next get a buffer. */
1311 skb = skb_peek(&sk->sk_receive_queue);
1316 /* Now that we have two receive queues this
1319 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1320 printk(KERN_INFO "recvmsg bug: copied %X "
1321 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1324 offset = *seq - TCP_SKB_CB(skb)->seq;
1327 if (offset < skb->len)
1331 BUG_TRAP(flags & MSG_PEEK);
1333 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1335 /* Well, if we have backlog, try to process it now yet. */
1337 if (copied >= target && !sk->sk_backlog.tail)
1342 sk->sk_state == TCP_CLOSE ||
1343 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1345 signal_pending(current) ||
1349 if (sock_flag(sk, SOCK_DONE))
1353 copied = sock_error(sk);
1357 if (sk->sk_shutdown & RCV_SHUTDOWN)
1360 if (sk->sk_state == TCP_CLOSE) {
1361 if (!sock_flag(sk, SOCK_DONE)) {
1362 /* This occurs when user tries to read
1363 * from never connected socket.
1376 if (signal_pending(current)) {
1377 copied = sock_intr_errno(timeo);
1382 cleanup_rbuf(sk, copied);
1384 if (tp->ucopy.task == user_recv) {
1385 /* Install new reader */
1386 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1387 user_recv = current;
1388 tp->ucopy.task = user_recv;
1389 tp->ucopy.iov = msg->msg_iov;
1392 tp->ucopy.len = len;
1394 BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1395 (flags & (MSG_PEEK | MSG_TRUNC)));
1397 /* Ugly... If prequeue is not empty, we have to
1398 * process it before releasing socket, otherwise
1399 * order will be broken at second iteration.
1400 * More elegant solution is required!!!
1402 * Look: we have the following (pseudo)queues:
1404 * 1. packets in flight
1409 * Each queue can be processed only if the next ones
1410 * are empty. At this point we have empty receive_queue.
1411 * But prequeue _can_ be not empty after 2nd iteration,
1412 * when we jumped to start of loop because backlog
1413 * processing added something to receive_queue.
1414 * We cannot release_sock(), because backlog contains
1415 * packets arrived _after_ prequeued ones.
1417 * Shortly, algorithm is clear --- to process all
1418 * the queues in order. We could make it more directly,
1419 * requeueing packets from backlog to prequeue, if
1420 * is not empty. It is more elegant, but eats cycles,
1423 if (skb_queue_len(&tp->ucopy.prequeue))
1426 /* __ Set realtime policy in scheduler __ */
1429 if (copied >= target) {
1430 /* Do not sleep, just process backlog. */
1434 sk_wait_data(sk, &timeo);
1439 /* __ Restore normal policy in scheduler __ */
1441 if ((chunk = len - tp->ucopy.len) != 0) {
1442 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1447 if (tp->rcv_nxt == tp->copied_seq &&
1448 skb_queue_len(&tp->ucopy.prequeue)) {
1450 tcp_prequeue_process(sk);
1452 if ((chunk = len - tp->ucopy.len) != 0) {
1453 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1459 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1460 if (net_ratelimit())
1461 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1462 current->comm, current->pid);
1463 peek_seq = tp->copied_seq;
1468 /* Ok so how much can we use? */
1469 used = skb->len - offset;
1473 /* Do we have urgent data here? */
1475 u32 urg_offset = tp->urg_seq - *seq;
1476 if (urg_offset < used) {
1478 if (!sock_flag(sk, SOCK_URGINLINE)) {
1490 if (!(flags & MSG_TRUNC)) {
1491 err = skb_copy_datagram_iovec(skb, offset,
1492 msg->msg_iov, used);
1494 /* Exception. Bailout! */
1505 tcp_rcv_space_adjust(sk);
1508 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1510 tcp_fast_path_check(sk, tp);
1512 if (used + offset < skb->len)
1517 if (!(flags & MSG_PEEK))
1518 sk_eat_skb(sk, skb);
1522 /* Process the FIN. */
1524 if (!(flags & MSG_PEEK))
1525 sk_eat_skb(sk, skb);
1530 if (skb_queue_len(&tp->ucopy.prequeue)) {
1533 tp->ucopy.len = copied > 0 ? len : 0;
1535 tcp_prequeue_process(sk);
1537 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1538 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1544 tp->ucopy.task = NULL;
1548 /* According to UNIX98, msg_name/msg_namelen are ignored
1549 * on connected socket. I was just happy when found this 8) --ANK
1552 /* Clean up data we have read: This will do ACK frames. */
1553 cleanup_rbuf(sk, copied);
1555 TCP_CHECK_TIMER(sk);
1560 TCP_CHECK_TIMER(sk);
1565 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1570 * State processing on a close. This implements the state shift for
1571 * sending our FIN frame. Note that we only send a FIN for some
1572 * states. A shutdown() may have already sent the FIN, or we may be
1576 static unsigned char new_state[16] = {
1577 /* current state: new state: action: */
1578 /* (Invalid) */ TCP_CLOSE,
1579 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1580 /* TCP_SYN_SENT */ TCP_CLOSE,
1581 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1582 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1583 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1584 /* TCP_TIME_WAIT */ TCP_CLOSE,
1585 /* TCP_CLOSE */ TCP_CLOSE,
1586 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1587 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1588 /* TCP_LISTEN */ TCP_CLOSE,
1589 /* TCP_CLOSING */ TCP_CLOSING,
1592 static int tcp_close_state(struct sock *sk)
1594 int next = (int)new_state[sk->sk_state];
1595 int ns = next & TCP_STATE_MASK;
1597 tcp_set_state(sk, ns);
1599 return next & TCP_ACTION_FIN;
1603 * Shutdown the sending side of a connection. Much like close except
1604 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1607 void tcp_shutdown(struct sock *sk, int how)
1609 /* We need to grab some memory, and put together a FIN,
1610 * and then put it into the queue to be sent.
1611 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1613 if (!(how & SEND_SHUTDOWN))
1616 /* If we've already sent a FIN, or it's a closed state, skip this. */
1617 if ((1 << sk->sk_state) &
1618 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1619 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1620 /* Clear out any half completed packets. FIN if needed. */
1621 if (tcp_close_state(sk))
1627 * At this point, there should be no process reference to this
1628 * socket, and thus no user references at all. Therefore we
1629 * can assume the socket waitqueue is inactive and nobody will
1630 * try to jump onto it.
1632 void tcp_destroy_sock(struct sock *sk)
1634 BUG_TRAP(sk->sk_state == TCP_CLOSE);
1635 BUG_TRAP(sock_flag(sk, SOCK_DEAD));
1637 /* It cannot be in hash table! */
1638 BUG_TRAP(sk_unhashed(sk));
1640 /* If it has not 0 inet_sk(sk)->num, it must be bound */
1641 BUG_TRAP(!inet_sk(sk)->num || tcp_sk(sk)->bind_hash);
1643 sk->sk_prot->destroy(sk);
1645 sk_stream_kill_queues(sk);
1647 xfrm_sk_free_policy(sk);
1649 #ifdef INET_REFCNT_DEBUG
1650 if (atomic_read(&sk->sk_refcnt) != 1) {
1651 printk(KERN_DEBUG "Destruction TCP %p delayed, c=%d\n",
1652 sk, atomic_read(&sk->sk_refcnt));
1656 atomic_dec(&tcp_orphan_count);
1660 void tcp_close(struct sock *sk, long timeout)
1662 struct sk_buff *skb;
1663 int data_was_unread = 0;
1666 sk->sk_shutdown = SHUTDOWN_MASK;
1668 if (sk->sk_state == TCP_LISTEN) {
1669 tcp_set_state(sk, TCP_CLOSE);
1672 tcp_listen_stop(sk);
1674 goto adjudge_to_death;
1677 /* We need to flush the recv. buffs. We do this only on the
1678 * descriptor close, not protocol-sourced closes, because the
1679 * reader process may not have drained the data yet!
1681 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1682 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1684 data_was_unread += len;
1688 sk_stream_mem_reclaim(sk);
1690 /* As outlined in draft-ietf-tcpimpl-prob-03.txt, section
1691 * 3.10, we send a RST here because data was lost. To
1692 * witness the awful effects of the old behavior of always
1693 * doing a FIN, run an older 2.1.x kernel or 2.0.x, start
1694 * a bulk GET in an FTP client, suspend the process, wait
1695 * for the client to advertise a zero window, then kill -9
1696 * the FTP client, wheee... Note: timeout is always zero
1699 if (data_was_unread) {
1700 /* Unread data was tossed, zap the connection. */
1701 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1702 tcp_set_state(sk, TCP_CLOSE);
1703 tcp_send_active_reset(sk, GFP_KERNEL);
1704 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1705 /* Check zero linger _after_ checking for unread data. */
1706 sk->sk_prot->disconnect(sk, 0);
1707 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1708 } else if (tcp_close_state(sk)) {
1709 /* We FIN if the application ate all the data before
1710 * zapping the connection.
1713 /* RED-PEN. Formally speaking, we have broken TCP state
1714 * machine. State transitions:
1716 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1717 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1718 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1720 * are legal only when FIN has been sent (i.e. in window),
1721 * rather than queued out of window. Purists blame.
1723 * F.e. "RFC state" is ESTABLISHED,
1724 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1726 * The visible declinations are that sometimes
1727 * we enter time-wait state, when it is not required really
1728 * (harmless), do not send active resets, when they are
1729 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1730 * they look as CLOSING or LAST_ACK for Linux)
1731 * Probably, I missed some more holelets.
1737 sk_stream_wait_close(sk, timeout);
1740 /* It is the last release_sock in its life. It will remove backlog. */
1744 /* Now socket is owned by kernel and we acquire BH lock
1745 to finish close. No need to check for user refs.
1749 BUG_TRAP(!sock_owned_by_user(sk));
1754 /* This is a (useful) BSD violating of the RFC. There is a
1755 * problem with TCP as specified in that the other end could
1756 * keep a socket open forever with no application left this end.
1757 * We use a 3 minute timeout (about the same as BSD) then kill
1758 * our end. If they send after that then tough - BUT: long enough
1759 * that we won't make the old 4*rto = almost no time - whoops
1762 * Nope, it was not mistake. It is really desired behaviour
1763 * f.e. on http servers, when such sockets are useless, but
1764 * consume significant resources. Let's do it with special
1765 * linger2 option. --ANK
1768 if (sk->sk_state == TCP_FIN_WAIT2) {
1769 struct tcp_opt *tp = tcp_sk(sk);
1770 if (tp->linger2 < 0) {
1771 tcp_set_state(sk, TCP_CLOSE);
1772 tcp_send_active_reset(sk, GFP_ATOMIC);
1773 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1775 int tmo = tcp_fin_time(tp);
1777 if (tmo > TCP_TIMEWAIT_LEN) {
1778 tcp_reset_keepalive_timer(sk, tcp_fin_time(tp));
1780 atomic_inc(&tcp_orphan_count);
1781 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1786 if (sk->sk_state != TCP_CLOSE) {
1787 sk_stream_mem_reclaim(sk);
1788 if (atomic_read(&tcp_orphan_count) > sysctl_tcp_max_orphans ||
1789 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
1790 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) {
1791 if (net_ratelimit())
1792 printk(KERN_INFO "TCP: too many of orphaned "
1794 tcp_set_state(sk, TCP_CLOSE);
1795 tcp_send_active_reset(sk, GFP_ATOMIC);
1796 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1799 atomic_inc(&tcp_orphan_count);
1801 if (sk->sk_state == TCP_CLOSE)
1802 tcp_destroy_sock(sk);
1803 /* Otherwise, socket is reprieved until protocol close. */
1811 /* These states need RST on ABORT according to RFC793 */
1813 static inline int tcp_need_reset(int state)
1815 return (1 << state) &
1816 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1817 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1820 int tcp_disconnect(struct sock *sk, int flags)
1822 struct inet_opt *inet = inet_sk(sk);
1823 struct tcp_opt *tp = tcp_sk(sk);
1825 int old_state = sk->sk_state;
1827 if (old_state != TCP_CLOSE)
1828 tcp_set_state(sk, TCP_CLOSE);
1830 /* ABORT function of RFC793 */
1831 if (old_state == TCP_LISTEN) {
1832 tcp_listen_stop(sk);
1833 } else if (tcp_need_reset(old_state) ||
1834 (tp->snd_nxt != tp->write_seq &&
1835 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1836 /* The last check adjusts for discrepance of Linux wrt. RFC
1839 tcp_send_active_reset(sk, gfp_any());
1840 sk->sk_err = ECONNRESET;
1841 } else if (old_state == TCP_SYN_SENT)
1842 sk->sk_err = ECONNRESET;
1844 tcp_clear_xmit_timers(sk);
1845 __skb_queue_purge(&sk->sk_receive_queue);
1846 sk_stream_writequeue_purge(sk);
1847 __skb_queue_purge(&tp->out_of_order_queue);
1851 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1852 inet_reset_saddr(sk);
1854 sk->sk_shutdown = 0;
1855 sock_reset_flag(sk, SOCK_DONE);
1857 if ((tp->write_seq += tp->max_window + 2) == 0)
1862 tcp_set_pcount(&tp->packets_out, 0);
1863 tp->snd_ssthresh = 0x7fffffff;
1864 tp->snd_cwnd_cnt = 0;
1865 tcp_set_ca_state(tp, TCP_CA_Open);
1866 tcp_clear_retrans(tp);
1867 tcp_delack_init(tp);
1868 sk->sk_send_head = NULL;
1873 BUG_TRAP(!inet->num || tp->bind_hash);
1875 sk->sk_error_report(sk);
1880 * Wait for an incoming connection, avoid race
1881 * conditions. This must be called with the socket locked.
1883 static int wait_for_connect(struct sock *sk, long timeo)
1885 struct tcp_opt *tp = tcp_sk(sk);
1890 * True wake-one mechanism for incoming connections: only
1891 * one process gets woken up, not the 'whole herd'.
1892 * Since we do not 'race & poll' for established sockets
1893 * anymore, the common case will execute the loop only once.
1895 * Subtle issue: "add_wait_queue_exclusive()" will be added
1896 * after any current non-exclusive waiters, and we know that
1897 * it will always _stay_ after any new non-exclusive waiters
1898 * because all non-exclusive waiters are added at the
1899 * beginning of the wait-queue. As such, it's ok to "drop"
1900 * our exclusiveness temporarily when we get woken up without
1901 * having to remove and re-insert us on the wait queue.
1904 prepare_to_wait_exclusive(sk->sk_sleep, &wait,
1905 TASK_INTERRUPTIBLE);
1907 if (!tp->accept_queue)
1908 timeo = schedule_timeout(timeo);
1911 if (tp->accept_queue)
1914 if (sk->sk_state != TCP_LISTEN)
1916 err = sock_intr_errno(timeo);
1917 if (signal_pending(current))
1923 finish_wait(sk->sk_sleep, &wait);
1928 * This will accept the next outstanding connection.
1931 struct sock *tcp_accept(struct sock *sk, int flags, int *err)
1933 struct tcp_opt *tp = tcp_sk(sk);
1934 struct open_request *req;
1937 #ifdef CONFIG_ACCEPT_QUEUES
1944 /* We need to make sure that this socket is listening,
1945 * and that it has something pending.
1948 if (sk->sk_state != TCP_LISTEN)
1951 /* Find already established connection */
1952 if (!tp->accept_queue) {
1953 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
1954 /* If this is a non blocking socket don't sleep */
1959 error = wait_for_connect(sk, timeo);
1964 #ifndef CONFIG_ACCEPT_QUEUES
1965 req = tp->accept_queue;
1966 if ((tp->accept_queue = req->dl_next) == NULL)
1967 tp->accept_queue_tail = NULL;
1969 sk_acceptq_removed(sk);
1971 first = tp->class_index;
1972 /* We should always have request queued here. The accept_queue
1973 * is already checked for NULL above.
1975 while(!tp->acceptq[first].aq_head) {
1976 tp->acceptq[first].aq_cnt = 0;
1977 first = (first+1) & ~NUM_ACCEPT_QUEUES;
1979 req = tp->acceptq[first].aq_head;
1980 tp->acceptq[first].aq_qcount--;
1981 tp->acceptq[first].aq_count++;
1982 tp->acceptq[first].aq_wait_time+=(jiffies - req->acceptq_time_stamp);
1984 for (prev_class= first-1 ; prev_class >=0; prev_class--)
1985 if (tp->acceptq[prev_class].aq_tail)
1988 tp->acceptq[prev_class].aq_tail->dl_next = req->dl_next;
1990 tp->accept_queue = req->dl_next;
1992 if (req == tp->acceptq[first].aq_tail)
1993 tp->acceptq[first].aq_head = tp->acceptq[first].aq_tail = NULL;
1995 tp->acceptq[first].aq_head = req->dl_next;
1997 if((++(tp->acceptq[first].aq_cnt)) >= tp->acceptq[first].aq_ratio){
1998 tp->acceptq[first].aq_cnt = 0;
1999 tp->class_index = ++first & (NUM_ACCEPT_QUEUES-1);
2002 sk_acceptq_removed(sk, req->acceptq_class);
2004 tcp_openreq_fastfree(req);
2005 BUG_TRAP(newsk->sk_state != TCP_SYN_RECV);
2017 * Socket option code for TCP.
2019 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2022 struct tcp_opt *tp = tcp_sk(sk);
2026 if (level != SOL_TCP)
2027 return tp->af_specific->setsockopt(sk, level, optname,
2030 if (optlen < sizeof(int))
2033 if (get_user(val, (int __user *)optval))
2040 /* Values greater than interface MTU won't take effect. However
2041 * at the point when this call is done we typically don't yet
2042 * know which interface is going to be used */
2043 if (val < 8 || val > MAX_TCP_WINDOW) {
2052 /* TCP_NODELAY is weaker than TCP_CORK, so that
2053 * this option on corked socket is remembered, but
2054 * it is not activated until cork is cleared.
2056 * However, when TCP_NODELAY is set we make
2057 * an explicit push, which overrides even TCP_CORK
2058 * for currently queued segments.
2060 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2061 tcp_push_pending_frames(sk, tp);
2063 tp->nonagle &= ~TCP_NAGLE_OFF;
2068 /* When set indicates to always queue non-full frames.
2069 * Later the user clears this option and we transmit
2070 * any pending partial frames in the queue. This is
2071 * meant to be used alongside sendfile() to get properly
2072 * filled frames when the user (for example) must write
2073 * out headers with a write() call first and then use
2074 * sendfile to send out the data parts.
2076 * TCP_CORK can be set together with TCP_NODELAY and it is
2077 * stronger than TCP_NODELAY.
2080 tp->nonagle |= TCP_NAGLE_CORK;
2082 tp->nonagle &= ~TCP_NAGLE_CORK;
2083 if (tp->nonagle&TCP_NAGLE_OFF)
2084 tp->nonagle |= TCP_NAGLE_PUSH;
2085 tcp_push_pending_frames(sk, tp);
2090 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2093 tp->keepalive_time = val * HZ;
2094 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2095 !((1 << sk->sk_state) &
2096 (TCPF_CLOSE | TCPF_LISTEN))) {
2097 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2098 if (tp->keepalive_time > elapsed)
2099 elapsed = tp->keepalive_time - elapsed;
2102 tcp_reset_keepalive_timer(sk, elapsed);
2107 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2110 tp->keepalive_intvl = val * HZ;
2113 if (val < 1 || val > MAX_TCP_KEEPCNT)
2116 tp->keepalive_probes = val;
2119 if (val < 1 || val > MAX_TCP_SYNCNT)
2122 tp->syn_retries = val;
2128 else if (val > sysctl_tcp_fin_timeout / HZ)
2131 tp->linger2 = val * HZ;
2134 case TCP_DEFER_ACCEPT:
2135 tp->defer_accept = 0;
2137 /* Translate value in seconds to number of
2139 while (tp->defer_accept < 32 &&
2140 val > ((TCP_TIMEOUT_INIT / HZ) <<
2147 case TCP_WINDOW_CLAMP:
2149 if (sk->sk_state != TCP_CLOSE) {
2153 tp->window_clamp = 0;
2155 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2156 SOCK_MIN_RCVBUF / 2 : val;
2161 tp->ack.pingpong = 1;
2163 tp->ack.pingpong = 0;
2164 if ((1 << sk->sk_state) &
2165 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2166 tcp_ack_scheduled(tp)) {
2167 tp->ack.pending |= TCP_ACK_PUSHED;
2168 cleanup_rbuf(sk, 1);
2170 tp->ack.pingpong = 1;
2175 #ifdef CONFIG_ACCEPT_QUEUES
2176 case TCP_ACCEPTQ_SHARE:
2178 // If CKRM is set then the shares are set through rcfs.
2179 // Get shares will still succeed.
2184 char share_wt[NUM_ACCEPT_QUEUES];
2187 if (sk->sk_state != TCP_LISTEN)
2190 if (copy_from_user(share_wt,optval, optlen)) {
2195 for (i = 0; i < NUM_ACCEPT_QUEUES; i++) {
2199 else if (share_wt[i] < j) {
2204 tp->acceptq[i].aq_ratio = 0;
2208 /* Class 0 is always valid. If nothing is
2209 * specified set class 0 as 1.
2214 for (i=0; i < NUM_ACCEPT_QUEUES; i++) {
2215 tp->acceptq[i].aq_ratio = share_wt[i]/j;
2216 tp->acceptq[i].aq_cnt = 0;
2230 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2233 struct tcp_opt *tp = tcp_sk(sk);
2236 if (level != SOL_TCP)
2237 return tp->af_specific->getsockopt(sk, level, optname,
2240 if (get_user(len, optlen))
2243 len = min_t(unsigned int, len, sizeof(int));
2250 val = tp->mss_cache_std;
2251 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2255 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2258 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2261 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2264 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2267 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2270 val = tp->syn_retries ? : sysctl_tcp_syn_retries;
2275 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2277 case TCP_DEFER_ACCEPT:
2278 val = !tp->defer_accept ? 0 : ((TCP_TIMEOUT_INIT / HZ) <<
2279 (tp->defer_accept - 1));
2281 case TCP_WINDOW_CLAMP:
2282 val = tp->window_clamp;
2285 struct tcp_info info;
2287 if (get_user(len, optlen))
2290 tcp_get_info(sk, &info);
2292 len = min_t(unsigned int, len, sizeof(info));
2293 if (put_user(len, optlen))
2295 if (copy_to_user(optval, &info, len))
2300 val = !tp->ack.pingpong;
2303 #ifdef CONFIG_ACCEPT_QUEUES
2304 case TCP_ACCEPTQ_SHARE:
2306 struct tcp_acceptq_info tinfo[NUM_ACCEPT_QUEUES];
2309 if (sk->sk_state != TCP_LISTEN)
2312 if (get_user(len, optlen))
2315 memset(tinfo, 0, sizeof(tinfo));
2317 for(i=0; i < NUM_ACCEPT_QUEUES; i++) {
2318 tinfo[i].acceptq_wait_time =
2319 jiffies_to_msecs(tp->acceptq[i].aq_wait_time);
2320 tinfo[i].acceptq_qcount = tp->acceptq[i].aq_qcount;
2321 tinfo[i].acceptq_count = tp->acceptq[i].aq_count;
2322 tinfo[i].acceptq_shares=tp->acceptq[i].aq_ratio;
2325 len = min_t(unsigned int, len, sizeof(tinfo));
2326 if (put_user(len, optlen))
2329 if (copy_to_user(optval, (char *)tinfo, len))
2337 return -ENOPROTOOPT;
2340 if (put_user(len, optlen))
2342 if (copy_to_user(optval, &val, len))
2348 extern void __skb_cb_too_small_for_tcp(int, int);
2349 extern void tcpdiag_init(void);
2351 static __initdata unsigned long thash_entries;
2352 static int __init set_thash_entries(char *str)
2356 thash_entries = simple_strtoul(str, &str, 0);
2359 __setup("thash_entries=", set_thash_entries);
2361 void __init tcp_init(void)
2363 struct sk_buff *skb = NULL;
2367 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2368 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2371 tcp_openreq_cachep = kmem_cache_create("tcp_open_request",
2372 sizeof(struct open_request),
2373 0, SLAB_HWCACHE_ALIGN,
2375 if (!tcp_openreq_cachep)
2376 panic("tcp_init: Cannot alloc open_request cache.");
2378 tcp_bucket_cachep = kmem_cache_create("tcp_bind_bucket",
2379 sizeof(struct tcp_bind_bucket),
2380 0, SLAB_HWCACHE_ALIGN,
2382 if (!tcp_bucket_cachep)
2383 panic("tcp_init: Cannot alloc tcp_bind_bucket cache.");
2385 tcp_timewait_cachep = kmem_cache_create("tcp_tw_bucket",
2386 sizeof(struct tcp_tw_bucket),
2387 0, SLAB_HWCACHE_ALIGN,
2389 if (!tcp_timewait_cachep)
2390 panic("tcp_init: Cannot alloc tcp_tw_bucket cache.");
2392 /* Size and allocate the main established and bind bucket
2395 * The methodology is similar to that of the buffer cache.
2397 if (num_physpages >= (128 * 1024))
2398 goal = num_physpages >> (21 - PAGE_SHIFT);
2400 goal = num_physpages >> (23 - PAGE_SHIFT);
2403 goal = (thash_entries * sizeof(struct tcp_ehash_bucket)) >> PAGE_SHIFT;
2404 for (order = 0; (1UL << order) < goal; order++)
2407 tcp_ehash_size = (1UL << order) * PAGE_SIZE /
2408 sizeof(struct tcp_ehash_bucket);
2409 tcp_ehash_size >>= 1;
2410 while (tcp_ehash_size & (tcp_ehash_size - 1))
2412 tcp_ehash = (struct tcp_ehash_bucket *)
2413 __get_free_pages(GFP_ATOMIC, order);
2414 } while (!tcp_ehash && --order > 0);
2417 panic("Failed to allocate TCP established hash table\n");
2418 for (i = 0; i < (tcp_ehash_size << 1); i++) {
2419 tcp_ehash[i].lock = RW_LOCK_UNLOCKED;
2420 INIT_HLIST_HEAD(&tcp_ehash[i].chain);
2424 tcp_bhash_size = (1UL << order) * PAGE_SIZE /
2425 sizeof(struct tcp_bind_hashbucket);
2426 if ((tcp_bhash_size > (64 * 1024)) && order > 0)
2428 tcp_bhash = (struct tcp_bind_hashbucket *)
2429 __get_free_pages(GFP_ATOMIC, order);
2430 } while (!tcp_bhash && --order >= 0);
2433 panic("Failed to allocate TCP bind hash table\n");
2434 for (i = 0; i < tcp_bhash_size; i++) {
2435 tcp_bhash[i].lock = SPIN_LOCK_UNLOCKED;
2436 INIT_HLIST_HEAD(&tcp_bhash[i].chain);
2439 /* Try to be a bit smarter and adjust defaults depending
2440 * on available memory.
2443 sysctl_local_port_range[0] = 32768;
2444 sysctl_local_port_range[1] = 61000;
2445 sysctl_tcp_max_tw_buckets = 180000;
2446 sysctl_tcp_max_orphans = 4096 << (order - 4);
2447 sysctl_max_syn_backlog = 1024;
2448 } else if (order < 3) {
2449 sysctl_local_port_range[0] = 1024 * (3 - order);
2450 sysctl_tcp_max_tw_buckets >>= (3 - order);
2451 sysctl_tcp_max_orphans >>= (3 - order);
2452 sysctl_max_syn_backlog = 128;
2454 tcp_port_rover = sysctl_local_port_range[0] - 1;
2456 sysctl_tcp_mem[0] = 768 << order;
2457 sysctl_tcp_mem[1] = 1024 << order;
2458 sysctl_tcp_mem[2] = 1536 << order;
2461 sysctl_tcp_wmem[2] = 64 * 1024;
2462 sysctl_tcp_rmem[0] = PAGE_SIZE;
2463 sysctl_tcp_rmem[1] = 43689;
2464 sysctl_tcp_rmem[2] = 2 * 43689;
2467 printk(KERN_INFO "TCP: Hash tables configured "
2468 "(established %d bind %d)\n",
2469 tcp_ehash_size << 1, tcp_bhash_size);
2474 EXPORT_SYMBOL(tcp_accept);
2475 EXPORT_SYMBOL(tcp_close);
2476 EXPORT_SYMBOL(tcp_destroy_sock);
2477 EXPORT_SYMBOL(tcp_disconnect);
2478 EXPORT_SYMBOL(tcp_getsockopt);
2479 EXPORT_SYMBOL(tcp_ioctl);
2480 EXPORT_SYMBOL(tcp_openreq_cachep);
2481 EXPORT_SYMBOL(tcp_poll);
2482 EXPORT_SYMBOL(tcp_read_sock);
2483 EXPORT_SYMBOL(tcp_recvmsg);
2484 EXPORT_SYMBOL(tcp_sendmsg);
2485 EXPORT_SYMBOL(tcp_sendpage);
2486 EXPORT_SYMBOL(tcp_setsockopt);
2487 EXPORT_SYMBOL(tcp_shutdown);
2488 EXPORT_SYMBOL(tcp_statistics);
2489 EXPORT_SYMBOL(tcp_timewait_cachep);
2490 EXPORT_SYMBOL_GPL(cleanup_rbuf);