m68k: use KBUILD_DEFCONFIG
[linux-2.6/verdex.git] / net / ipv4 / tcp.c
blob39b629ac240411d6092622dc543abfe4f0779dc5
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
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
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>
22 * Fixes:
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
27 * (tcp_err()).
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
38 * unknown sockets.
39 * Alan Cox : tcp option processing.
40 * Alan Cox : Reset tweaked (still not 100%) [Had
41 * syn rule wrong]
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
47 * escape still
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
51 * facilities
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
56 * bit to skb ops.
57 * Alan Cox : Tidied tcp_data to avoid a potential
58 * nasty.
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
70 * sockets.
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
74 * state ack error.
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
79 * fixes
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
85 * completely
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
93 * (not yet usable)
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
106 * all cases.
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
111 * works now.
112 * Michael Pall : recv(...,MSG_OOB) never blocks in the
113 * BSD api.
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
121 * fixed ports.
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
127 * socket close.
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
132 * accept.
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
143 * close.
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
149 * comments.
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
157 * resemble the RFC.
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
162 * generates them.
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
175 * but it's a start!
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
196 * improvement.
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
228 * to shutdown
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/kernel.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/fs.h>
257 #include <linux/skbuff.h>
258 #include <linux/splice.h>
259 #include <linux/net.h>
260 #include <linux/socket.h>
261 #include <linux/random.h>
262 #include <linux/bootmem.h>
263 #include <linux/cache.h>
264 #include <linux/err.h>
265 #include <linux/crypto.h>
267 #include <net/icmp.h>
268 #include <net/tcp.h>
269 #include <net/xfrm.h>
270 #include <net/ip.h>
271 #include <net/netdma.h>
272 #include <net/sock.h>
274 #include <asm/uaccess.h>
275 #include <asm/ioctls.h>
277 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
279 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly;
281 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
283 EXPORT_SYMBOL_GPL(tcp_orphan_count);
285 int sysctl_tcp_mem[3] __read_mostly;
286 int sysctl_tcp_wmem[3] __read_mostly;
287 int sysctl_tcp_rmem[3] __read_mostly;
289 EXPORT_SYMBOL(sysctl_tcp_mem);
290 EXPORT_SYMBOL(sysctl_tcp_rmem);
291 EXPORT_SYMBOL(sysctl_tcp_wmem);
293 atomic_t tcp_memory_allocated; /* Current allocated memory. */
294 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
296 EXPORT_SYMBOL(tcp_memory_allocated);
297 EXPORT_SYMBOL(tcp_sockets_allocated);
300 * TCP splice context
302 struct tcp_splice_state {
303 struct pipe_inode_info *pipe;
304 size_t len;
305 unsigned int flags;
309 * Pressure flag: try to collapse.
310 * Technical note: it is used by multiple contexts non atomically.
311 * All the __sk_mem_schedule() is of this nature: accounting
312 * is strict, actions are advisory and have some latency.
314 int tcp_memory_pressure __read_mostly;
316 EXPORT_SYMBOL(tcp_memory_pressure);
318 void tcp_enter_memory_pressure(void)
320 if (!tcp_memory_pressure) {
321 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
322 tcp_memory_pressure = 1;
326 EXPORT_SYMBOL(tcp_enter_memory_pressure);
329 * Wait for a TCP event.
331 * Note that we don't need to lock the socket, as the upper poll layers
332 * take care of normal races (between the test and the event) and we don't
333 * go look at any of the socket buffers directly.
335 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
337 unsigned int mask;
338 struct sock *sk = sock->sk;
339 struct tcp_sock *tp = tcp_sk(sk);
341 poll_wait(file, sk->sk_sleep, wait);
342 if (sk->sk_state == TCP_LISTEN)
343 return inet_csk_listen_poll(sk);
345 /* Socket is not locked. We are protected from async events
346 by poll logic and correct handling of state changes
347 made by another threads is impossible in any case.
350 mask = 0;
351 if (sk->sk_err)
352 mask = POLLERR;
355 * POLLHUP is certainly not done right. But poll() doesn't
356 * have a notion of HUP in just one direction, and for a
357 * socket the read side is more interesting.
359 * Some poll() documentation says that POLLHUP is incompatible
360 * with the POLLOUT/POLLWR flags, so somebody should check this
361 * all. But careful, it tends to be safer to return too many
362 * bits than too few, and you can easily break real applications
363 * if you don't tell them that something has hung up!
365 * Check-me.
367 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
368 * our fs/select.c). It means that after we received EOF,
369 * poll always returns immediately, making impossible poll() on write()
370 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
371 * if and only if shutdown has been made in both directions.
372 * Actually, it is interesting to look how Solaris and DUX
373 * solve this dilemma. I would prefer, if PULLHUP were maskable,
374 * then we could set it on SND_SHUTDOWN. BTW examples given
375 * in Stevens' books assume exactly this behaviour, it explains
376 * why PULLHUP is incompatible with POLLOUT. --ANK
378 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
379 * blocking on fresh not-connected or disconnected socket. --ANK
381 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
382 mask |= POLLHUP;
383 if (sk->sk_shutdown & RCV_SHUTDOWN)
384 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
386 /* Connected? */
387 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
388 /* Potential race condition. If read of tp below will
389 * escape above sk->sk_state, we can be illegally awaken
390 * in SYN_* states. */
391 if ((tp->rcv_nxt != tp->copied_seq) &&
392 (tp->urg_seq != tp->copied_seq ||
393 tp->rcv_nxt != tp->copied_seq + 1 ||
394 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
395 mask |= POLLIN | POLLRDNORM;
397 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
398 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
399 mask |= POLLOUT | POLLWRNORM;
400 } else { /* send SIGIO later */
401 set_bit(SOCK_ASYNC_NOSPACE,
402 &sk->sk_socket->flags);
403 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
405 /* Race breaker. If space is freed after
406 * wspace test but before the flags are set,
407 * IO signal will be lost.
409 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
410 mask |= POLLOUT | POLLWRNORM;
414 if (tp->urg_data & TCP_URG_VALID)
415 mask |= POLLPRI;
417 return mask;
420 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
422 struct tcp_sock *tp = tcp_sk(sk);
423 int answ;
425 switch (cmd) {
426 case SIOCINQ:
427 if (sk->sk_state == TCP_LISTEN)
428 return -EINVAL;
430 lock_sock(sk);
431 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
432 answ = 0;
433 else if (sock_flag(sk, SOCK_URGINLINE) ||
434 !tp->urg_data ||
435 before(tp->urg_seq, tp->copied_seq) ||
436 !before(tp->urg_seq, tp->rcv_nxt)) {
437 answ = tp->rcv_nxt - tp->copied_seq;
439 /* Subtract 1, if FIN is in queue. */
440 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
441 answ -=
442 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin;
443 } else
444 answ = tp->urg_seq - tp->copied_seq;
445 release_sock(sk);
446 break;
447 case SIOCATMARK:
448 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
449 break;
450 case SIOCOUTQ:
451 if (sk->sk_state == TCP_LISTEN)
452 return -EINVAL;
454 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
455 answ = 0;
456 else
457 answ = tp->write_seq - tp->snd_una;
458 break;
459 default:
460 return -ENOIOCTLCMD;
463 return put_user(answ, (int __user *)arg);
466 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
468 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
469 tp->pushed_seq = tp->write_seq;
472 static inline int forced_push(struct tcp_sock *tp)
474 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
477 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
479 struct tcp_sock *tp = tcp_sk(sk);
480 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
482 skb->csum = 0;
483 tcb->seq = tcb->end_seq = tp->write_seq;
484 tcb->flags = TCPCB_FLAG_ACK;
485 tcb->sacked = 0;
486 skb_header_release(skb);
487 tcp_add_write_queue_tail(sk, skb);
488 sk->sk_wmem_queued += skb->truesize;
489 sk_mem_charge(sk, skb->truesize);
490 if (tp->nonagle & TCP_NAGLE_PUSH)
491 tp->nonagle &= ~TCP_NAGLE_PUSH;
494 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
495 struct sk_buff *skb)
497 if (flags & MSG_OOB) {
498 tp->urg_mode = 1;
499 tp->snd_up = tp->write_seq;
503 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
504 int nonagle)
506 struct tcp_sock *tp = tcp_sk(sk);
508 if (tcp_send_head(sk)) {
509 struct sk_buff *skb = tcp_write_queue_tail(sk);
510 if (!(flags & MSG_MORE) || forced_push(tp))
511 tcp_mark_push(tp, skb);
512 tcp_mark_urg(tp, flags, skb);
513 __tcp_push_pending_frames(sk, mss_now,
514 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
518 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
519 unsigned int offset, size_t len)
521 struct tcp_splice_state *tss = rd_desc->arg.data;
523 return skb_splice_bits(skb, offset, tss->pipe, tss->len, tss->flags);
526 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
528 /* Store TCP splice context information in read_descriptor_t. */
529 read_descriptor_t rd_desc = {
530 .arg.data = tss,
533 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
537 * tcp_splice_read - splice data from TCP socket to a pipe
538 * @sock: socket to splice from
539 * @ppos: position (not valid)
540 * @pipe: pipe to splice to
541 * @len: number of bytes to splice
542 * @flags: splice modifier flags
544 * Description:
545 * Will read pages from given socket and fill them into a pipe.
548 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
549 struct pipe_inode_info *pipe, size_t len,
550 unsigned int flags)
552 struct sock *sk = sock->sk;
553 struct tcp_splice_state tss = {
554 .pipe = pipe,
555 .len = len,
556 .flags = flags,
558 long timeo;
559 ssize_t spliced;
560 int ret;
563 * We can't seek on a socket input
565 if (unlikely(*ppos))
566 return -ESPIPE;
568 ret = spliced = 0;
570 lock_sock(sk);
572 timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK);
573 while (tss.len) {
574 ret = __tcp_splice_read(sk, &tss);
575 if (ret < 0)
576 break;
577 else if (!ret) {
578 if (spliced)
579 break;
580 if (flags & SPLICE_F_NONBLOCK) {
581 ret = -EAGAIN;
582 break;
584 if (sock_flag(sk, SOCK_DONE))
585 break;
586 if (sk->sk_err) {
587 ret = sock_error(sk);
588 break;
590 if (sk->sk_shutdown & RCV_SHUTDOWN)
591 break;
592 if (sk->sk_state == TCP_CLOSE) {
594 * This occurs when user tries to read
595 * from never connected socket.
597 if (!sock_flag(sk, SOCK_DONE))
598 ret = -ENOTCONN;
599 break;
601 if (!timeo) {
602 ret = -EAGAIN;
603 break;
605 sk_wait_data(sk, &timeo);
606 if (signal_pending(current)) {
607 ret = sock_intr_errno(timeo);
608 break;
610 continue;
612 tss.len -= ret;
613 spliced += ret;
615 release_sock(sk);
616 lock_sock(sk);
618 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
619 (sk->sk_shutdown & RCV_SHUTDOWN) || !timeo ||
620 signal_pending(current))
621 break;
624 release_sock(sk);
626 if (spliced)
627 return spliced;
629 return ret;
632 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
634 struct sk_buff *skb;
636 /* The TCP header must be at least 32-bit aligned. */
637 size = ALIGN(size, 4);
639 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
640 if (skb) {
641 if (sk_wmem_schedule(sk, skb->truesize)) {
643 * Make sure that we have exactly size bytes
644 * available to the caller, no more, no less.
646 skb_reserve(skb, skb_tailroom(skb) - size);
647 return skb;
649 __kfree_skb(skb);
650 } else {
651 sk->sk_prot->enter_memory_pressure();
652 sk_stream_moderate_sndbuf(sk);
654 return NULL;
657 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
658 size_t psize, int flags)
660 struct tcp_sock *tp = tcp_sk(sk);
661 int mss_now, size_goal;
662 int err;
663 ssize_t copied;
664 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
666 /* Wait for a connection to finish. */
667 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
668 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
669 goto out_err;
671 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
673 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
674 size_goal = tp->xmit_size_goal;
675 copied = 0;
677 err = -EPIPE;
678 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
679 goto do_error;
681 while (psize > 0) {
682 struct sk_buff *skb = tcp_write_queue_tail(sk);
683 struct page *page = pages[poffset / PAGE_SIZE];
684 int copy, i, can_coalesce;
685 int offset = poffset % PAGE_SIZE;
686 int size = min_t(size_t, psize, PAGE_SIZE - offset);
688 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
689 new_segment:
690 if (!sk_stream_memory_free(sk))
691 goto wait_for_sndbuf;
693 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
694 if (!skb)
695 goto wait_for_memory;
697 skb_entail(sk, skb);
698 copy = size_goal;
701 if (copy > size)
702 copy = size;
704 i = skb_shinfo(skb)->nr_frags;
705 can_coalesce = skb_can_coalesce(skb, i, page, offset);
706 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
707 tcp_mark_push(tp, skb);
708 goto new_segment;
710 if (!sk_wmem_schedule(sk, copy))
711 goto wait_for_memory;
713 if (can_coalesce) {
714 skb_shinfo(skb)->frags[i - 1].size += copy;
715 } else {
716 get_page(page);
717 skb_fill_page_desc(skb, i, page, offset, copy);
720 skb->len += copy;
721 skb->data_len += copy;
722 skb->truesize += copy;
723 sk->sk_wmem_queued += copy;
724 sk_mem_charge(sk, copy);
725 skb->ip_summed = CHECKSUM_PARTIAL;
726 tp->write_seq += copy;
727 TCP_SKB_CB(skb)->end_seq += copy;
728 skb_shinfo(skb)->gso_segs = 0;
730 if (!copied)
731 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
733 copied += copy;
734 poffset += copy;
735 if (!(psize -= copy))
736 goto out;
738 if (skb->len < size_goal || (flags & MSG_OOB))
739 continue;
741 if (forced_push(tp)) {
742 tcp_mark_push(tp, skb);
743 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
744 } else if (skb == tcp_send_head(sk))
745 tcp_push_one(sk, mss_now);
746 continue;
748 wait_for_sndbuf:
749 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
750 wait_for_memory:
751 if (copied)
752 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
754 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
755 goto do_error;
757 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
758 size_goal = tp->xmit_size_goal;
761 out:
762 if (copied)
763 tcp_push(sk, flags, mss_now, tp->nonagle);
764 return copied;
766 do_error:
767 if (copied)
768 goto out;
769 out_err:
770 return sk_stream_error(sk, flags, err);
773 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
774 size_t size, int flags)
776 ssize_t res;
777 struct sock *sk = sock->sk;
779 if (!(sk->sk_route_caps & NETIF_F_SG) ||
780 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
781 return sock_no_sendpage(sock, page, offset, size, flags);
783 lock_sock(sk);
784 TCP_CHECK_TIMER(sk);
785 res = do_tcp_sendpages(sk, &page, offset, size, flags);
786 TCP_CHECK_TIMER(sk);
787 release_sock(sk);
788 return res;
791 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
792 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
794 static inline int select_size(struct sock *sk)
796 struct tcp_sock *tp = tcp_sk(sk);
797 int tmp = tp->mss_cache;
799 if (sk->sk_route_caps & NETIF_F_SG) {
800 if (sk_can_gso(sk))
801 tmp = 0;
802 else {
803 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
805 if (tmp >= pgbreak &&
806 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
807 tmp = pgbreak;
811 return tmp;
814 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
815 size_t size)
817 struct sock *sk = sock->sk;
818 struct iovec *iov;
819 struct tcp_sock *tp = tcp_sk(sk);
820 struct sk_buff *skb;
821 int iovlen, flags;
822 int mss_now, size_goal;
823 int err, copied;
824 long timeo;
826 lock_sock(sk);
827 TCP_CHECK_TIMER(sk);
829 flags = msg->msg_flags;
830 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
832 /* Wait for a connection to finish. */
833 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
834 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
835 goto out_err;
837 /* This should be in poll */
838 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
840 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
841 size_goal = tp->xmit_size_goal;
843 /* Ok commence sending. */
844 iovlen = msg->msg_iovlen;
845 iov = msg->msg_iov;
846 copied = 0;
848 err = -EPIPE;
849 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
850 goto do_error;
852 while (--iovlen >= 0) {
853 int seglen = iov->iov_len;
854 unsigned char __user *from = iov->iov_base;
856 iov++;
858 while (seglen > 0) {
859 int copy;
861 skb = tcp_write_queue_tail(sk);
863 if (!tcp_send_head(sk) ||
864 (copy = size_goal - skb->len) <= 0) {
866 new_segment:
867 /* Allocate new segment. If the interface is SG,
868 * allocate skb fitting to single page.
870 if (!sk_stream_memory_free(sk))
871 goto wait_for_sndbuf;
873 skb = sk_stream_alloc_skb(sk, select_size(sk),
874 sk->sk_allocation);
875 if (!skb)
876 goto wait_for_memory;
879 * Check whether we can use HW checksum.
881 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
882 skb->ip_summed = CHECKSUM_PARTIAL;
884 skb_entail(sk, skb);
885 copy = size_goal;
888 /* Try to append data to the end of skb. */
889 if (copy > seglen)
890 copy = seglen;
892 /* Where to copy to? */
893 if (skb_tailroom(skb) > 0) {
894 /* We have some space in skb head. Superb! */
895 if (copy > skb_tailroom(skb))
896 copy = skb_tailroom(skb);
897 if ((err = skb_add_data(skb, from, copy)) != 0)
898 goto do_fault;
899 } else {
900 int merge = 0;
901 int i = skb_shinfo(skb)->nr_frags;
902 struct page *page = TCP_PAGE(sk);
903 int off = TCP_OFF(sk);
905 if (skb_can_coalesce(skb, i, page, off) &&
906 off != PAGE_SIZE) {
907 /* We can extend the last page
908 * fragment. */
909 merge = 1;
910 } else if (i == MAX_SKB_FRAGS ||
911 (!i &&
912 !(sk->sk_route_caps & NETIF_F_SG))) {
913 /* Need to add new fragment and cannot
914 * do this because interface is non-SG,
915 * or because all the page slots are
916 * busy. */
917 tcp_mark_push(tp, skb);
918 goto new_segment;
919 } else if (page) {
920 if (off == PAGE_SIZE) {
921 put_page(page);
922 TCP_PAGE(sk) = page = NULL;
923 off = 0;
925 } else
926 off = 0;
928 if (copy > PAGE_SIZE - off)
929 copy = PAGE_SIZE - off;
931 if (!sk_wmem_schedule(sk, copy))
932 goto wait_for_memory;
934 if (!page) {
935 /* Allocate new cache page. */
936 if (!(page = sk_stream_alloc_page(sk)))
937 goto wait_for_memory;
940 /* Time to copy data. We are close to
941 * the end! */
942 err = skb_copy_to_page(sk, from, skb, page,
943 off, copy);
944 if (err) {
945 /* If this page was new, give it to the
946 * socket so it does not get leaked.
948 if (!TCP_PAGE(sk)) {
949 TCP_PAGE(sk) = page;
950 TCP_OFF(sk) = 0;
952 goto do_error;
955 /* Update the skb. */
956 if (merge) {
957 skb_shinfo(skb)->frags[i - 1].size +=
958 copy;
959 } else {
960 skb_fill_page_desc(skb, i, page, off, copy);
961 if (TCP_PAGE(sk)) {
962 get_page(page);
963 } else if (off + copy < PAGE_SIZE) {
964 get_page(page);
965 TCP_PAGE(sk) = page;
969 TCP_OFF(sk) = off + copy;
972 if (!copied)
973 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
975 tp->write_seq += copy;
976 TCP_SKB_CB(skb)->end_seq += copy;
977 skb_shinfo(skb)->gso_segs = 0;
979 from += copy;
980 copied += copy;
981 if ((seglen -= copy) == 0 && iovlen == 0)
982 goto out;
984 if (skb->len < size_goal || (flags & MSG_OOB))
985 continue;
987 if (forced_push(tp)) {
988 tcp_mark_push(tp, skb);
989 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
990 } else if (skb == tcp_send_head(sk))
991 tcp_push_one(sk, mss_now);
992 continue;
994 wait_for_sndbuf:
995 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
996 wait_for_memory:
997 if (copied)
998 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1000 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1001 goto do_error;
1003 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
1004 size_goal = tp->xmit_size_goal;
1008 out:
1009 if (copied)
1010 tcp_push(sk, flags, mss_now, tp->nonagle);
1011 TCP_CHECK_TIMER(sk);
1012 release_sock(sk);
1013 return copied;
1015 do_fault:
1016 if (!skb->len) {
1017 tcp_unlink_write_queue(skb, sk);
1018 /* It is the one place in all of TCP, except connection
1019 * reset, where we can be unlinking the send_head.
1021 tcp_check_send_head(sk, skb);
1022 sk_wmem_free_skb(sk, skb);
1025 do_error:
1026 if (copied)
1027 goto out;
1028 out_err:
1029 err = sk_stream_error(sk, flags, err);
1030 TCP_CHECK_TIMER(sk);
1031 release_sock(sk);
1032 return err;
1036 * Handle reading urgent data. BSD has very simple semantics for
1037 * this, no blocking and very strange errors 8)
1040 static int tcp_recv_urg(struct sock *sk, long timeo,
1041 struct msghdr *msg, int len, int flags,
1042 int *addr_len)
1044 struct tcp_sock *tp = tcp_sk(sk);
1046 /* No URG data to read. */
1047 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1048 tp->urg_data == TCP_URG_READ)
1049 return -EINVAL; /* Yes this is right ! */
1051 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1052 return -ENOTCONN;
1054 if (tp->urg_data & TCP_URG_VALID) {
1055 int err = 0;
1056 char c = tp->urg_data;
1058 if (!(flags & MSG_PEEK))
1059 tp->urg_data = TCP_URG_READ;
1061 /* Read urgent data. */
1062 msg->msg_flags |= MSG_OOB;
1064 if (len > 0) {
1065 if (!(flags & MSG_TRUNC))
1066 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1067 len = 1;
1068 } else
1069 msg->msg_flags |= MSG_TRUNC;
1071 return err ? -EFAULT : len;
1074 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1075 return 0;
1077 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1078 * the available implementations agree in this case:
1079 * this call should never block, independent of the
1080 * blocking state of the socket.
1081 * Mike <pall@rz.uni-karlsruhe.de>
1083 return -EAGAIN;
1086 /* Clean up the receive buffer for full frames taken by the user,
1087 * then send an ACK if necessary. COPIED is the number of bytes
1088 * tcp_recvmsg has given to the user so far, it speeds up the
1089 * calculation of whether or not we must ACK for the sake of
1090 * a window update.
1092 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1094 struct tcp_sock *tp = tcp_sk(sk);
1095 int time_to_ack = 0;
1097 #if TCP_DEBUG
1098 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1100 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
1101 #endif
1103 if (inet_csk_ack_scheduled(sk)) {
1104 const struct inet_connection_sock *icsk = inet_csk(sk);
1105 /* Delayed ACKs frequently hit locked sockets during bulk
1106 * receive. */
1107 if (icsk->icsk_ack.blocked ||
1108 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1109 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1111 * If this read emptied read buffer, we send ACK, if
1112 * connection is not bidirectional, user drained
1113 * receive buffer and there was a small segment
1114 * in queue.
1116 (copied > 0 &&
1117 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1118 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1119 !icsk->icsk_ack.pingpong)) &&
1120 !atomic_read(&sk->sk_rmem_alloc)))
1121 time_to_ack = 1;
1124 /* We send an ACK if we can now advertise a non-zero window
1125 * which has been raised "significantly".
1127 * Even if window raised up to infinity, do not send window open ACK
1128 * in states, where we will not receive more. It is useless.
1130 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1131 __u32 rcv_window_now = tcp_receive_window(tp);
1133 /* Optimize, __tcp_select_window() is not cheap. */
1134 if (2*rcv_window_now <= tp->window_clamp) {
1135 __u32 new_window = __tcp_select_window(sk);
1137 /* Send ACK now, if this read freed lots of space
1138 * in our buffer. Certainly, new_window is new window.
1139 * We can advertise it now, if it is not less than current one.
1140 * "Lots" means "at least twice" here.
1142 if (new_window && new_window >= 2 * rcv_window_now)
1143 time_to_ack = 1;
1146 if (time_to_ack)
1147 tcp_send_ack(sk);
1150 static void tcp_prequeue_process(struct sock *sk)
1152 struct sk_buff *skb;
1153 struct tcp_sock *tp = tcp_sk(sk);
1155 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
1157 /* RX process wants to run with disabled BHs, though it is not
1158 * necessary */
1159 local_bh_disable();
1160 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1161 sk->sk_backlog_rcv(sk, skb);
1162 local_bh_enable();
1164 /* Clear memory counter. */
1165 tp->ucopy.memory = 0;
1168 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1170 struct sk_buff *skb;
1171 u32 offset;
1173 skb_queue_walk(&sk->sk_receive_queue, skb) {
1174 offset = seq - TCP_SKB_CB(skb)->seq;
1175 if (tcp_hdr(skb)->syn)
1176 offset--;
1177 if (offset < skb->len || tcp_hdr(skb)->fin) {
1178 *off = offset;
1179 return skb;
1182 return NULL;
1186 * This routine provides an alternative to tcp_recvmsg() for routines
1187 * that would like to handle copying from skbuffs directly in 'sendfile'
1188 * fashion.
1189 * Note:
1190 * - It is assumed that the socket was locked by the caller.
1191 * - The routine does not block.
1192 * - At present, there is no support for reading OOB data
1193 * or for 'peeking' the socket using this routine
1194 * (although both would be easy to implement).
1196 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1197 sk_read_actor_t recv_actor)
1199 struct sk_buff *skb;
1200 struct tcp_sock *tp = tcp_sk(sk);
1201 u32 seq = tp->copied_seq;
1202 u32 offset;
1203 int copied = 0;
1205 if (sk->sk_state == TCP_LISTEN)
1206 return -ENOTCONN;
1207 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1208 if (offset < skb->len) {
1209 size_t used, len;
1211 len = skb->len - offset;
1212 /* Stop reading if we hit a patch of urgent data */
1213 if (tp->urg_data) {
1214 u32 urg_offset = tp->urg_seq - seq;
1215 if (urg_offset < len)
1216 len = urg_offset;
1217 if (!len)
1218 break;
1220 used = recv_actor(desc, skb, offset, len);
1221 if (used < 0) {
1222 if (!copied)
1223 copied = used;
1224 break;
1225 } else if (used <= len) {
1226 seq += used;
1227 copied += used;
1228 offset += used;
1230 if (offset != skb->len)
1231 break;
1233 if (tcp_hdr(skb)->fin) {
1234 sk_eat_skb(sk, skb, 0);
1235 ++seq;
1236 break;
1238 sk_eat_skb(sk, skb, 0);
1239 if (!desc->count)
1240 break;
1242 tp->copied_seq = seq;
1244 tcp_rcv_space_adjust(sk);
1246 /* Clean up data we have read: This will do ACK frames. */
1247 if (copied > 0)
1248 tcp_cleanup_rbuf(sk, copied);
1249 return 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_sock *tp = tcp_sk(sk);
1264 int copied = 0;
1265 u32 peek_seq;
1266 u32 *seq;
1267 unsigned long used;
1268 int err;
1269 int target; /* Read at least this many bytes */
1270 long timeo;
1271 struct task_struct *user_recv = NULL;
1272 int copied_early = 0;
1273 struct sk_buff *skb;
1275 lock_sock(sk);
1277 TCP_CHECK_TIMER(sk);
1279 err = -ENOTCONN;
1280 if (sk->sk_state == TCP_LISTEN)
1281 goto out;
1283 timeo = sock_rcvtimeo(sk, nonblock);
1285 /* Urgent data needs to be handled specially. */
1286 if (flags & MSG_OOB)
1287 goto recv_urg;
1289 seq = &tp->copied_seq;
1290 if (flags & MSG_PEEK) {
1291 peek_seq = tp->copied_seq;
1292 seq = &peek_seq;
1295 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1297 #ifdef CONFIG_NET_DMA
1298 tp->ucopy.dma_chan = NULL;
1299 preempt_disable();
1300 skb = skb_peek_tail(&sk->sk_receive_queue);
1302 int available = 0;
1304 if (skb)
1305 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1306 if ((available < target) &&
1307 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1308 !sysctl_tcp_low_latency &&
1309 __get_cpu_var(softnet_data).net_dma) {
1310 preempt_enable_no_resched();
1311 tp->ucopy.pinned_list =
1312 dma_pin_iovec_pages(msg->msg_iov, len);
1313 } else {
1314 preempt_enable_no_resched();
1317 #endif
1319 do {
1320 u32 offset;
1322 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1323 if (tp->urg_data && tp->urg_seq == *seq) {
1324 if (copied)
1325 break;
1326 if (signal_pending(current)) {
1327 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1328 break;
1332 /* Next get a buffer. */
1334 skb = skb_peek(&sk->sk_receive_queue);
1335 do {
1336 if (!skb)
1337 break;
1339 /* Now that we have two receive queues this
1340 * shouldn't happen.
1342 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1343 printk(KERN_INFO "recvmsg bug: copied %X "
1344 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1345 break;
1347 offset = *seq - TCP_SKB_CB(skb)->seq;
1348 if (tcp_hdr(skb)->syn)
1349 offset--;
1350 if (offset < skb->len)
1351 goto found_ok_skb;
1352 if (tcp_hdr(skb)->fin)
1353 goto found_fin_ok;
1354 BUG_TRAP(flags & MSG_PEEK);
1355 skb = skb->next;
1356 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1358 /* Well, if we have backlog, try to process it now yet. */
1360 if (copied >= target && !sk->sk_backlog.tail)
1361 break;
1363 if (copied) {
1364 if (sk->sk_err ||
1365 sk->sk_state == TCP_CLOSE ||
1366 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1367 !timeo ||
1368 signal_pending(current) ||
1369 (flags & MSG_PEEK))
1370 break;
1371 } else {
1372 if (sock_flag(sk, SOCK_DONE))
1373 break;
1375 if (sk->sk_err) {
1376 copied = sock_error(sk);
1377 break;
1380 if (sk->sk_shutdown & RCV_SHUTDOWN)
1381 break;
1383 if (sk->sk_state == TCP_CLOSE) {
1384 if (!sock_flag(sk, SOCK_DONE)) {
1385 /* This occurs when user tries to read
1386 * from never connected socket.
1388 copied = -ENOTCONN;
1389 break;
1391 break;
1394 if (!timeo) {
1395 copied = -EAGAIN;
1396 break;
1399 if (signal_pending(current)) {
1400 copied = sock_intr_errno(timeo);
1401 break;
1405 tcp_cleanup_rbuf(sk, copied);
1407 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1408 /* Install new reader */
1409 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1410 user_recv = current;
1411 tp->ucopy.task = user_recv;
1412 tp->ucopy.iov = msg->msg_iov;
1415 tp->ucopy.len = len;
1417 BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1418 (flags & (MSG_PEEK | MSG_TRUNC)));
1420 /* Ugly... If prequeue is not empty, we have to
1421 * process it before releasing socket, otherwise
1422 * order will be broken at second iteration.
1423 * More elegant solution is required!!!
1425 * Look: we have the following (pseudo)queues:
1427 * 1. packets in flight
1428 * 2. backlog
1429 * 3. prequeue
1430 * 4. receive_queue
1432 * Each queue can be processed only if the next ones
1433 * are empty. At this point we have empty receive_queue.
1434 * But prequeue _can_ be not empty after 2nd iteration,
1435 * when we jumped to start of loop because backlog
1436 * processing added something to receive_queue.
1437 * We cannot release_sock(), because backlog contains
1438 * packets arrived _after_ prequeued ones.
1440 * Shortly, algorithm is clear --- to process all
1441 * the queues in order. We could make it more directly,
1442 * requeueing packets from backlog to prequeue, if
1443 * is not empty. It is more elegant, but eats cycles,
1444 * unfortunately.
1446 if (!skb_queue_empty(&tp->ucopy.prequeue))
1447 goto do_prequeue;
1449 /* __ Set realtime policy in scheduler __ */
1452 if (copied >= target) {
1453 /* Do not sleep, just process backlog. */
1454 release_sock(sk);
1455 lock_sock(sk);
1456 } else
1457 sk_wait_data(sk, &timeo);
1459 #ifdef CONFIG_NET_DMA
1460 tp->ucopy.wakeup = 0;
1461 #endif
1463 if (user_recv) {
1464 int chunk;
1466 /* __ Restore normal policy in scheduler __ */
1468 if ((chunk = len - tp->ucopy.len) != 0) {
1469 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1470 len -= chunk;
1471 copied += chunk;
1474 if (tp->rcv_nxt == tp->copied_seq &&
1475 !skb_queue_empty(&tp->ucopy.prequeue)) {
1476 do_prequeue:
1477 tcp_prequeue_process(sk);
1479 if ((chunk = len - tp->ucopy.len) != 0) {
1480 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1481 len -= chunk;
1482 copied += chunk;
1486 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1487 if (net_ratelimit())
1488 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1489 current->comm, task_pid_nr(current));
1490 peek_seq = tp->copied_seq;
1492 continue;
1494 found_ok_skb:
1495 /* Ok so how much can we use? */
1496 used = skb->len - offset;
1497 if (len < used)
1498 used = len;
1500 /* Do we have urgent data here? */
1501 if (tp->urg_data) {
1502 u32 urg_offset = tp->urg_seq - *seq;
1503 if (urg_offset < used) {
1504 if (!urg_offset) {
1505 if (!sock_flag(sk, SOCK_URGINLINE)) {
1506 ++*seq;
1507 offset++;
1508 used--;
1509 if (!used)
1510 goto skip_copy;
1512 } else
1513 used = urg_offset;
1517 if (!(flags & MSG_TRUNC)) {
1518 #ifdef CONFIG_NET_DMA
1519 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1520 tp->ucopy.dma_chan = get_softnet_dma();
1522 if (tp->ucopy.dma_chan) {
1523 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1524 tp->ucopy.dma_chan, skb, offset,
1525 msg->msg_iov, used,
1526 tp->ucopy.pinned_list);
1528 if (tp->ucopy.dma_cookie < 0) {
1530 printk(KERN_ALERT "dma_cookie < 0\n");
1532 /* Exception. Bailout! */
1533 if (!copied)
1534 copied = -EFAULT;
1535 break;
1537 if ((offset + used) == skb->len)
1538 copied_early = 1;
1540 } else
1541 #endif
1543 err = skb_copy_datagram_iovec(skb, offset,
1544 msg->msg_iov, used);
1545 if (err) {
1546 /* Exception. Bailout! */
1547 if (!copied)
1548 copied = -EFAULT;
1549 break;
1554 *seq += used;
1555 copied += used;
1556 len -= used;
1558 tcp_rcv_space_adjust(sk);
1560 skip_copy:
1561 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1562 tp->urg_data = 0;
1563 tcp_fast_path_check(sk);
1565 if (used + offset < skb->len)
1566 continue;
1568 if (tcp_hdr(skb)->fin)
1569 goto found_fin_ok;
1570 if (!(flags & MSG_PEEK)) {
1571 sk_eat_skb(sk, skb, copied_early);
1572 copied_early = 0;
1574 continue;
1576 found_fin_ok:
1577 /* Process the FIN. */
1578 ++*seq;
1579 if (!(flags & MSG_PEEK)) {
1580 sk_eat_skb(sk, skb, copied_early);
1581 copied_early = 0;
1583 break;
1584 } while (len > 0);
1586 if (user_recv) {
1587 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1588 int chunk;
1590 tp->ucopy.len = copied > 0 ? len : 0;
1592 tcp_prequeue_process(sk);
1594 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1595 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1596 len -= chunk;
1597 copied += chunk;
1601 tp->ucopy.task = NULL;
1602 tp->ucopy.len = 0;
1605 #ifdef CONFIG_NET_DMA
1606 if (tp->ucopy.dma_chan) {
1607 dma_cookie_t done, used;
1609 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1611 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1612 tp->ucopy.dma_cookie, &done,
1613 &used) == DMA_IN_PROGRESS) {
1614 /* do partial cleanup of sk_async_wait_queue */
1615 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1616 (dma_async_is_complete(skb->dma_cookie, done,
1617 used) == DMA_SUCCESS)) {
1618 __skb_dequeue(&sk->sk_async_wait_queue);
1619 kfree_skb(skb);
1623 /* Safe to free early-copied skbs now */
1624 __skb_queue_purge(&sk->sk_async_wait_queue);
1625 dma_chan_put(tp->ucopy.dma_chan);
1626 tp->ucopy.dma_chan = NULL;
1628 if (tp->ucopy.pinned_list) {
1629 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1630 tp->ucopy.pinned_list = NULL;
1632 #endif
1634 /* According to UNIX98, msg_name/msg_namelen are ignored
1635 * on connected socket. I was just happy when found this 8) --ANK
1638 /* Clean up data we have read: This will do ACK frames. */
1639 tcp_cleanup_rbuf(sk, copied);
1641 TCP_CHECK_TIMER(sk);
1642 release_sock(sk);
1643 return copied;
1645 out:
1646 TCP_CHECK_TIMER(sk);
1647 release_sock(sk);
1648 return err;
1650 recv_urg:
1651 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1652 goto out;
1655 void tcp_set_state(struct sock *sk, int state)
1657 int oldstate = sk->sk_state;
1659 switch (state) {
1660 case TCP_ESTABLISHED:
1661 if (oldstate != TCP_ESTABLISHED)
1662 TCP_INC_STATS(TCP_MIB_CURRESTAB);
1663 break;
1665 case TCP_CLOSE:
1666 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1667 TCP_INC_STATS(TCP_MIB_ESTABRESETS);
1669 sk->sk_prot->unhash(sk);
1670 if (inet_csk(sk)->icsk_bind_hash &&
1671 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1672 inet_put_port(sk);
1673 /* fall through */
1674 default:
1675 if (oldstate==TCP_ESTABLISHED)
1676 TCP_DEC_STATS(TCP_MIB_CURRESTAB);
1679 /* Change state AFTER socket is unhashed to avoid closed
1680 * socket sitting in hash tables.
1682 sk->sk_state = state;
1684 #ifdef STATE_TRACE
1685 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]);
1686 #endif
1688 EXPORT_SYMBOL_GPL(tcp_set_state);
1691 * State processing on a close. This implements the state shift for
1692 * sending our FIN frame. Note that we only send a FIN for some
1693 * states. A shutdown() may have already sent the FIN, or we may be
1694 * closed.
1697 static const unsigned char new_state[16] = {
1698 /* current state: new state: action: */
1699 /* (Invalid) */ TCP_CLOSE,
1700 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1701 /* TCP_SYN_SENT */ TCP_CLOSE,
1702 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1703 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1704 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1705 /* TCP_TIME_WAIT */ TCP_CLOSE,
1706 /* TCP_CLOSE */ TCP_CLOSE,
1707 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1708 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1709 /* TCP_LISTEN */ TCP_CLOSE,
1710 /* TCP_CLOSING */ TCP_CLOSING,
1713 static int tcp_close_state(struct sock *sk)
1715 int next = (int)new_state[sk->sk_state];
1716 int ns = next & TCP_STATE_MASK;
1718 tcp_set_state(sk, ns);
1720 return next & TCP_ACTION_FIN;
1724 * Shutdown the sending side of a connection. Much like close except
1725 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1728 void tcp_shutdown(struct sock *sk, int how)
1730 /* We need to grab some memory, and put together a FIN,
1731 * and then put it into the queue to be sent.
1732 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1734 if (!(how & SEND_SHUTDOWN))
1735 return;
1737 /* If we've already sent a FIN, or it's a closed state, skip this. */
1738 if ((1 << sk->sk_state) &
1739 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1740 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1741 /* Clear out any half completed packets. FIN if needed. */
1742 if (tcp_close_state(sk))
1743 tcp_send_fin(sk);
1747 void tcp_close(struct sock *sk, long timeout)
1749 struct sk_buff *skb;
1750 int data_was_unread = 0;
1751 int state;
1753 lock_sock(sk);
1754 sk->sk_shutdown = SHUTDOWN_MASK;
1756 if (sk->sk_state == TCP_LISTEN) {
1757 tcp_set_state(sk, TCP_CLOSE);
1759 /* Special case. */
1760 inet_csk_listen_stop(sk);
1762 goto adjudge_to_death;
1765 /* We need to flush the recv. buffs. We do this only on the
1766 * descriptor close, not protocol-sourced closes, because the
1767 * reader process may not have drained the data yet!
1769 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1770 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1771 tcp_hdr(skb)->fin;
1772 data_was_unread += len;
1773 __kfree_skb(skb);
1776 sk_mem_reclaim(sk);
1778 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1779 * data was lost. To witness the awful effects of the old behavior of
1780 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1781 * GET in an FTP client, suspend the process, wait for the client to
1782 * advertise a zero window, then kill -9 the FTP client, wheee...
1783 * Note: timeout is always zero in such a case.
1785 if (data_was_unread) {
1786 /* Unread data was tossed, zap the connection. */
1787 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1788 tcp_set_state(sk, TCP_CLOSE);
1789 tcp_send_active_reset(sk, GFP_KERNEL);
1790 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1791 /* Check zero linger _after_ checking for unread data. */
1792 sk->sk_prot->disconnect(sk, 0);
1793 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1794 } else if (tcp_close_state(sk)) {
1795 /* We FIN if the application ate all the data before
1796 * zapping the connection.
1799 /* RED-PEN. Formally speaking, we have broken TCP state
1800 * machine. State transitions:
1802 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1803 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1804 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1806 * are legal only when FIN has been sent (i.e. in window),
1807 * rather than queued out of window. Purists blame.
1809 * F.e. "RFC state" is ESTABLISHED,
1810 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1812 * The visible declinations are that sometimes
1813 * we enter time-wait state, when it is not required really
1814 * (harmless), do not send active resets, when they are
1815 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1816 * they look as CLOSING or LAST_ACK for Linux)
1817 * Probably, I missed some more holelets.
1818 * --ANK
1820 tcp_send_fin(sk);
1823 sk_stream_wait_close(sk, timeout);
1825 adjudge_to_death:
1826 state = sk->sk_state;
1827 sock_hold(sk);
1828 sock_orphan(sk);
1829 atomic_inc(sk->sk_prot->orphan_count);
1831 /* It is the last release_sock in its life. It will remove backlog. */
1832 release_sock(sk);
1835 /* Now socket is owned by kernel and we acquire BH lock
1836 to finish close. No need to check for user refs.
1838 local_bh_disable();
1839 bh_lock_sock(sk);
1840 BUG_TRAP(!sock_owned_by_user(sk));
1842 /* Have we already been destroyed by a softirq or backlog? */
1843 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1844 goto out;
1846 /* This is a (useful) BSD violating of the RFC. There is a
1847 * problem with TCP as specified in that the other end could
1848 * keep a socket open forever with no application left this end.
1849 * We use a 3 minute timeout (about the same as BSD) then kill
1850 * our end. If they send after that then tough - BUT: long enough
1851 * that we won't make the old 4*rto = almost no time - whoops
1852 * reset mistake.
1854 * Nope, it was not mistake. It is really desired behaviour
1855 * f.e. on http servers, when such sockets are useless, but
1856 * consume significant resources. Let's do it with special
1857 * linger2 option. --ANK
1860 if (sk->sk_state == TCP_FIN_WAIT2) {
1861 struct tcp_sock *tp = tcp_sk(sk);
1862 if (tp->linger2 < 0) {
1863 tcp_set_state(sk, TCP_CLOSE);
1864 tcp_send_active_reset(sk, GFP_ATOMIC);
1865 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1866 } else {
1867 const int tmo = tcp_fin_time(sk);
1869 if (tmo > TCP_TIMEWAIT_LEN) {
1870 inet_csk_reset_keepalive_timer(sk,
1871 tmo - TCP_TIMEWAIT_LEN);
1872 } else {
1873 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1874 goto out;
1878 if (sk->sk_state != TCP_CLOSE) {
1879 sk_mem_reclaim(sk);
1880 if (tcp_too_many_orphans(sk,
1881 atomic_read(sk->sk_prot->orphan_count))) {
1882 if (net_ratelimit())
1883 printk(KERN_INFO "TCP: too many of orphaned "
1884 "sockets\n");
1885 tcp_set_state(sk, TCP_CLOSE);
1886 tcp_send_active_reset(sk, GFP_ATOMIC);
1887 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1891 if (sk->sk_state == TCP_CLOSE)
1892 inet_csk_destroy_sock(sk);
1893 /* Otherwise, socket is reprieved until protocol close. */
1895 out:
1896 bh_unlock_sock(sk);
1897 local_bh_enable();
1898 sock_put(sk);
1901 /* These states need RST on ABORT according to RFC793 */
1903 static inline int tcp_need_reset(int state)
1905 return (1 << state) &
1906 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1907 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1910 int tcp_disconnect(struct sock *sk, int flags)
1912 struct inet_sock *inet = inet_sk(sk);
1913 struct inet_connection_sock *icsk = inet_csk(sk);
1914 struct tcp_sock *tp = tcp_sk(sk);
1915 int err = 0;
1916 int old_state = sk->sk_state;
1918 if (old_state != TCP_CLOSE)
1919 tcp_set_state(sk, TCP_CLOSE);
1921 /* ABORT function of RFC793 */
1922 if (old_state == TCP_LISTEN) {
1923 inet_csk_listen_stop(sk);
1924 } else if (tcp_need_reset(old_state) ||
1925 (tp->snd_nxt != tp->write_seq &&
1926 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1927 /* The last check adjusts for discrepancy of Linux wrt. RFC
1928 * states
1930 tcp_send_active_reset(sk, gfp_any());
1931 sk->sk_err = ECONNRESET;
1932 } else if (old_state == TCP_SYN_SENT)
1933 sk->sk_err = ECONNRESET;
1935 tcp_clear_xmit_timers(sk);
1936 __skb_queue_purge(&sk->sk_receive_queue);
1937 tcp_write_queue_purge(sk);
1938 __skb_queue_purge(&tp->out_of_order_queue);
1939 #ifdef CONFIG_NET_DMA
1940 __skb_queue_purge(&sk->sk_async_wait_queue);
1941 #endif
1943 inet->dport = 0;
1945 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1946 inet_reset_saddr(sk);
1948 sk->sk_shutdown = 0;
1949 sock_reset_flag(sk, SOCK_DONE);
1950 tp->srtt = 0;
1951 if ((tp->write_seq += tp->max_window + 2) == 0)
1952 tp->write_seq = 1;
1953 icsk->icsk_backoff = 0;
1954 tp->snd_cwnd = 2;
1955 icsk->icsk_probes_out = 0;
1956 tp->packets_out = 0;
1957 tp->snd_ssthresh = 0x7fffffff;
1958 tp->snd_cwnd_cnt = 0;
1959 tp->bytes_acked = 0;
1960 tcp_set_ca_state(sk, TCP_CA_Open);
1961 tcp_clear_retrans(tp);
1962 inet_csk_delack_init(sk);
1963 tcp_init_send_head(sk);
1964 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
1965 __sk_dst_reset(sk);
1967 BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1969 sk->sk_error_report(sk);
1970 return err;
1974 * Socket option code for TCP.
1976 static int do_tcp_setsockopt(struct sock *sk, int level,
1977 int optname, char __user *optval, int optlen)
1979 struct tcp_sock *tp = tcp_sk(sk);
1980 struct inet_connection_sock *icsk = inet_csk(sk);
1981 int val;
1982 int err = 0;
1984 /* This is a string value all the others are int's */
1985 if (optname == TCP_CONGESTION) {
1986 char name[TCP_CA_NAME_MAX];
1988 if (optlen < 1)
1989 return -EINVAL;
1991 val = strncpy_from_user(name, optval,
1992 min(TCP_CA_NAME_MAX-1, optlen));
1993 if (val < 0)
1994 return -EFAULT;
1995 name[val] = 0;
1997 lock_sock(sk);
1998 err = tcp_set_congestion_control(sk, name);
1999 release_sock(sk);
2000 return err;
2003 if (optlen < sizeof(int))
2004 return -EINVAL;
2006 if (get_user(val, (int __user *)optval))
2007 return -EFAULT;
2009 lock_sock(sk);
2011 switch (optname) {
2012 case TCP_MAXSEG:
2013 /* Values greater than interface MTU won't take effect. However
2014 * at the point when this call is done we typically don't yet
2015 * know which interface is going to be used */
2016 if (val < 8 || val > MAX_TCP_WINDOW) {
2017 err = -EINVAL;
2018 break;
2020 tp->rx_opt.user_mss = val;
2021 break;
2023 case TCP_NODELAY:
2024 if (val) {
2025 /* TCP_NODELAY is weaker than TCP_CORK, so that
2026 * this option on corked socket is remembered, but
2027 * it is not activated until cork is cleared.
2029 * However, when TCP_NODELAY is set we make
2030 * an explicit push, which overrides even TCP_CORK
2031 * for currently queued segments.
2033 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2034 tcp_push_pending_frames(sk);
2035 } else {
2036 tp->nonagle &= ~TCP_NAGLE_OFF;
2038 break;
2040 case TCP_CORK:
2041 /* When set indicates to always queue non-full frames.
2042 * Later the user clears this option and we transmit
2043 * any pending partial frames in the queue. This is
2044 * meant to be used alongside sendfile() to get properly
2045 * filled frames when the user (for example) must write
2046 * out headers with a write() call first and then use
2047 * sendfile to send out the data parts.
2049 * TCP_CORK can be set together with TCP_NODELAY and it is
2050 * stronger than TCP_NODELAY.
2052 if (val) {
2053 tp->nonagle |= TCP_NAGLE_CORK;
2054 } else {
2055 tp->nonagle &= ~TCP_NAGLE_CORK;
2056 if (tp->nonagle&TCP_NAGLE_OFF)
2057 tp->nonagle |= TCP_NAGLE_PUSH;
2058 tcp_push_pending_frames(sk);
2060 break;
2062 case TCP_KEEPIDLE:
2063 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2064 err = -EINVAL;
2065 else {
2066 tp->keepalive_time = val * HZ;
2067 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2068 !((1 << sk->sk_state) &
2069 (TCPF_CLOSE | TCPF_LISTEN))) {
2070 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2071 if (tp->keepalive_time > elapsed)
2072 elapsed = tp->keepalive_time - elapsed;
2073 else
2074 elapsed = 0;
2075 inet_csk_reset_keepalive_timer(sk, elapsed);
2078 break;
2079 case TCP_KEEPINTVL:
2080 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2081 err = -EINVAL;
2082 else
2083 tp->keepalive_intvl = val * HZ;
2084 break;
2085 case TCP_KEEPCNT:
2086 if (val < 1 || val > MAX_TCP_KEEPCNT)
2087 err = -EINVAL;
2088 else
2089 tp->keepalive_probes = val;
2090 break;
2091 case TCP_SYNCNT:
2092 if (val < 1 || val > MAX_TCP_SYNCNT)
2093 err = -EINVAL;
2094 else
2095 icsk->icsk_syn_retries = val;
2096 break;
2098 case TCP_LINGER2:
2099 if (val < 0)
2100 tp->linger2 = -1;
2101 else if (val > sysctl_tcp_fin_timeout / HZ)
2102 tp->linger2 = 0;
2103 else
2104 tp->linger2 = val * HZ;
2105 break;
2107 case TCP_DEFER_ACCEPT:
2108 icsk->icsk_accept_queue.rskq_defer_accept = 0;
2109 if (val > 0) {
2110 /* Translate value in seconds to number of
2111 * retransmits */
2112 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
2113 val > ((TCP_TIMEOUT_INIT / HZ) <<
2114 icsk->icsk_accept_queue.rskq_defer_accept))
2115 icsk->icsk_accept_queue.rskq_defer_accept++;
2116 icsk->icsk_accept_queue.rskq_defer_accept++;
2118 break;
2120 case TCP_WINDOW_CLAMP:
2121 if (!val) {
2122 if (sk->sk_state != TCP_CLOSE) {
2123 err = -EINVAL;
2124 break;
2126 tp->window_clamp = 0;
2127 } else
2128 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2129 SOCK_MIN_RCVBUF / 2 : val;
2130 break;
2132 case TCP_QUICKACK:
2133 if (!val) {
2134 icsk->icsk_ack.pingpong = 1;
2135 } else {
2136 icsk->icsk_ack.pingpong = 0;
2137 if ((1 << sk->sk_state) &
2138 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2139 inet_csk_ack_scheduled(sk)) {
2140 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2141 tcp_cleanup_rbuf(sk, 1);
2142 if (!(val & 1))
2143 icsk->icsk_ack.pingpong = 1;
2146 break;
2148 #ifdef CONFIG_TCP_MD5SIG
2149 case TCP_MD5SIG:
2150 /* Read the IP->Key mappings from userspace */
2151 err = tp->af_specific->md5_parse(sk, optval, optlen);
2152 break;
2153 #endif
2155 default:
2156 err = -ENOPROTOOPT;
2157 break;
2160 release_sock(sk);
2161 return err;
2164 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2165 int optlen)
2167 struct inet_connection_sock *icsk = inet_csk(sk);
2169 if (level != SOL_TCP)
2170 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2171 optval, optlen);
2172 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2175 #ifdef CONFIG_COMPAT
2176 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2177 char __user *optval, int optlen)
2179 if (level != SOL_TCP)
2180 return inet_csk_compat_setsockopt(sk, level, optname,
2181 optval, optlen);
2182 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2185 EXPORT_SYMBOL(compat_tcp_setsockopt);
2186 #endif
2188 /* Return information about state of tcp endpoint in API format. */
2189 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2191 struct tcp_sock *tp = tcp_sk(sk);
2192 const struct inet_connection_sock *icsk = inet_csk(sk);
2193 u32 now = tcp_time_stamp;
2195 memset(info, 0, sizeof(*info));
2197 info->tcpi_state = sk->sk_state;
2198 info->tcpi_ca_state = icsk->icsk_ca_state;
2199 info->tcpi_retransmits = icsk->icsk_retransmits;
2200 info->tcpi_probes = icsk->icsk_probes_out;
2201 info->tcpi_backoff = icsk->icsk_backoff;
2203 if (tp->rx_opt.tstamp_ok)
2204 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2205 if (tcp_is_sack(tp))
2206 info->tcpi_options |= TCPI_OPT_SACK;
2207 if (tp->rx_opt.wscale_ok) {
2208 info->tcpi_options |= TCPI_OPT_WSCALE;
2209 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2210 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2213 if (tp->ecn_flags&TCP_ECN_OK)
2214 info->tcpi_options |= TCPI_OPT_ECN;
2216 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2217 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2218 info->tcpi_snd_mss = tp->mss_cache;
2219 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2221 if (sk->sk_state == TCP_LISTEN) {
2222 info->tcpi_unacked = sk->sk_ack_backlog;
2223 info->tcpi_sacked = sk->sk_max_ack_backlog;
2224 } else {
2225 info->tcpi_unacked = tp->packets_out;
2226 info->tcpi_sacked = tp->sacked_out;
2228 info->tcpi_lost = tp->lost_out;
2229 info->tcpi_retrans = tp->retrans_out;
2230 info->tcpi_fackets = tp->fackets_out;
2232 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2233 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2234 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2236 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2237 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2238 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2239 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2240 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2241 info->tcpi_snd_cwnd = tp->snd_cwnd;
2242 info->tcpi_advmss = tp->advmss;
2243 info->tcpi_reordering = tp->reordering;
2245 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2246 info->tcpi_rcv_space = tp->rcvq_space.space;
2248 info->tcpi_total_retrans = tp->total_retrans;
2251 EXPORT_SYMBOL_GPL(tcp_get_info);
2253 static int do_tcp_getsockopt(struct sock *sk, int level,
2254 int optname, char __user *optval, int __user *optlen)
2256 struct inet_connection_sock *icsk = inet_csk(sk);
2257 struct tcp_sock *tp = tcp_sk(sk);
2258 int val, len;
2260 if (get_user(len, optlen))
2261 return -EFAULT;
2263 len = min_t(unsigned int, len, sizeof(int));
2265 if (len < 0)
2266 return -EINVAL;
2268 switch (optname) {
2269 case TCP_MAXSEG:
2270 val = tp->mss_cache;
2271 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2272 val = tp->rx_opt.user_mss;
2273 break;
2274 case TCP_NODELAY:
2275 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2276 break;
2277 case TCP_CORK:
2278 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2279 break;
2280 case TCP_KEEPIDLE:
2281 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2282 break;
2283 case TCP_KEEPINTVL:
2284 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2285 break;
2286 case TCP_KEEPCNT:
2287 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2288 break;
2289 case TCP_SYNCNT:
2290 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2291 break;
2292 case TCP_LINGER2:
2293 val = tp->linger2;
2294 if (val >= 0)
2295 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2296 break;
2297 case TCP_DEFER_ACCEPT:
2298 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2299 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2300 break;
2301 case TCP_WINDOW_CLAMP:
2302 val = tp->window_clamp;
2303 break;
2304 case TCP_INFO: {
2305 struct tcp_info info;
2307 if (get_user(len, optlen))
2308 return -EFAULT;
2310 tcp_get_info(sk, &info);
2312 len = min_t(unsigned int, len, sizeof(info));
2313 if (put_user(len, optlen))
2314 return -EFAULT;
2315 if (copy_to_user(optval, &info, len))
2316 return -EFAULT;
2317 return 0;
2319 case TCP_QUICKACK:
2320 val = !icsk->icsk_ack.pingpong;
2321 break;
2323 case TCP_CONGESTION:
2324 if (get_user(len, optlen))
2325 return -EFAULT;
2326 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2327 if (put_user(len, optlen))
2328 return -EFAULT;
2329 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2330 return -EFAULT;
2331 return 0;
2332 default:
2333 return -ENOPROTOOPT;
2336 if (put_user(len, optlen))
2337 return -EFAULT;
2338 if (copy_to_user(optval, &val, len))
2339 return -EFAULT;
2340 return 0;
2343 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2344 int __user *optlen)
2346 struct inet_connection_sock *icsk = inet_csk(sk);
2348 if (level != SOL_TCP)
2349 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2350 optval, optlen);
2351 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2354 #ifdef CONFIG_COMPAT
2355 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2356 char __user *optval, int __user *optlen)
2358 if (level != SOL_TCP)
2359 return inet_csk_compat_getsockopt(sk, level, optname,
2360 optval, optlen);
2361 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2364 EXPORT_SYMBOL(compat_tcp_getsockopt);
2365 #endif
2367 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2369 struct sk_buff *segs = ERR_PTR(-EINVAL);
2370 struct tcphdr *th;
2371 unsigned thlen;
2372 unsigned int seq;
2373 __be32 delta;
2374 unsigned int oldlen;
2375 unsigned int len;
2377 if (!pskb_may_pull(skb, sizeof(*th)))
2378 goto out;
2380 th = tcp_hdr(skb);
2381 thlen = th->doff * 4;
2382 if (thlen < sizeof(*th))
2383 goto out;
2385 if (!pskb_may_pull(skb, thlen))
2386 goto out;
2388 oldlen = (u16)~skb->len;
2389 __skb_pull(skb, thlen);
2391 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2392 /* Packet is from an untrusted source, reset gso_segs. */
2393 int type = skb_shinfo(skb)->gso_type;
2394 int mss;
2396 if (unlikely(type &
2397 ~(SKB_GSO_TCPV4 |
2398 SKB_GSO_DODGY |
2399 SKB_GSO_TCP_ECN |
2400 SKB_GSO_TCPV6 |
2401 0) ||
2402 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2403 goto out;
2405 mss = skb_shinfo(skb)->gso_size;
2406 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2408 segs = NULL;
2409 goto out;
2412 segs = skb_segment(skb, features);
2413 if (IS_ERR(segs))
2414 goto out;
2416 len = skb_shinfo(skb)->gso_size;
2417 delta = htonl(oldlen + (thlen + len));
2419 skb = segs;
2420 th = tcp_hdr(skb);
2421 seq = ntohl(th->seq);
2423 do {
2424 th->fin = th->psh = 0;
2426 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2427 (__force u32)delta));
2428 if (skb->ip_summed != CHECKSUM_PARTIAL)
2429 th->check =
2430 csum_fold(csum_partial(skb_transport_header(skb),
2431 thlen, skb->csum));
2433 seq += len;
2434 skb = skb->next;
2435 th = tcp_hdr(skb);
2437 th->seq = htonl(seq);
2438 th->cwr = 0;
2439 } while (skb->next);
2441 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2442 skb->data_len);
2443 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2444 (__force u32)delta));
2445 if (skb->ip_summed != CHECKSUM_PARTIAL)
2446 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2447 thlen, skb->csum));
2449 out:
2450 return segs;
2452 EXPORT_SYMBOL(tcp_tso_segment);
2454 #ifdef CONFIG_TCP_MD5SIG
2455 static unsigned long tcp_md5sig_users;
2456 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2457 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2459 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2461 int cpu;
2462 for_each_possible_cpu(cpu) {
2463 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2464 if (p) {
2465 if (p->md5_desc.tfm)
2466 crypto_free_hash(p->md5_desc.tfm);
2467 kfree(p);
2468 p = NULL;
2471 free_percpu(pool);
2474 void tcp_free_md5sig_pool(void)
2476 struct tcp_md5sig_pool **pool = NULL;
2478 spin_lock_bh(&tcp_md5sig_pool_lock);
2479 if (--tcp_md5sig_users == 0) {
2480 pool = tcp_md5sig_pool;
2481 tcp_md5sig_pool = NULL;
2483 spin_unlock_bh(&tcp_md5sig_pool_lock);
2484 if (pool)
2485 __tcp_free_md5sig_pool(pool);
2488 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2490 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
2492 int cpu;
2493 struct tcp_md5sig_pool **pool;
2495 pool = alloc_percpu(struct tcp_md5sig_pool *);
2496 if (!pool)
2497 return NULL;
2499 for_each_possible_cpu(cpu) {
2500 struct tcp_md5sig_pool *p;
2501 struct crypto_hash *hash;
2503 p = kzalloc(sizeof(*p), GFP_KERNEL);
2504 if (!p)
2505 goto out_free;
2506 *per_cpu_ptr(pool, cpu) = p;
2508 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2509 if (!hash || IS_ERR(hash))
2510 goto out_free;
2512 p->md5_desc.tfm = hash;
2514 return pool;
2515 out_free:
2516 __tcp_free_md5sig_pool(pool);
2517 return NULL;
2520 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
2522 struct tcp_md5sig_pool **pool;
2523 int alloc = 0;
2525 retry:
2526 spin_lock_bh(&tcp_md5sig_pool_lock);
2527 pool = tcp_md5sig_pool;
2528 if (tcp_md5sig_users++ == 0) {
2529 alloc = 1;
2530 spin_unlock_bh(&tcp_md5sig_pool_lock);
2531 } else if (!pool) {
2532 tcp_md5sig_users--;
2533 spin_unlock_bh(&tcp_md5sig_pool_lock);
2534 cpu_relax();
2535 goto retry;
2536 } else
2537 spin_unlock_bh(&tcp_md5sig_pool_lock);
2539 if (alloc) {
2540 /* we cannot hold spinlock here because this may sleep. */
2541 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
2542 spin_lock_bh(&tcp_md5sig_pool_lock);
2543 if (!p) {
2544 tcp_md5sig_users--;
2545 spin_unlock_bh(&tcp_md5sig_pool_lock);
2546 return NULL;
2548 pool = tcp_md5sig_pool;
2549 if (pool) {
2550 /* oops, it has already been assigned. */
2551 spin_unlock_bh(&tcp_md5sig_pool_lock);
2552 __tcp_free_md5sig_pool(p);
2553 } else {
2554 tcp_md5sig_pool = pool = p;
2555 spin_unlock_bh(&tcp_md5sig_pool_lock);
2558 return pool;
2561 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2563 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2565 struct tcp_md5sig_pool **p;
2566 spin_lock_bh(&tcp_md5sig_pool_lock);
2567 p = tcp_md5sig_pool;
2568 if (p)
2569 tcp_md5sig_users++;
2570 spin_unlock_bh(&tcp_md5sig_pool_lock);
2571 return (p ? *per_cpu_ptr(p, cpu) : NULL);
2574 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2576 void __tcp_put_md5sig_pool(void)
2578 tcp_free_md5sig_pool();
2581 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2582 #endif
2584 void tcp_done(struct sock *sk)
2586 if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2587 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
2589 tcp_set_state(sk, TCP_CLOSE);
2590 tcp_clear_xmit_timers(sk);
2592 sk->sk_shutdown = SHUTDOWN_MASK;
2594 if (!sock_flag(sk, SOCK_DEAD))
2595 sk->sk_state_change(sk);
2596 else
2597 inet_csk_destroy_sock(sk);
2599 EXPORT_SYMBOL_GPL(tcp_done);
2601 extern struct tcp_congestion_ops tcp_reno;
2603 static __initdata unsigned long thash_entries;
2604 static int __init set_thash_entries(char *str)
2606 if (!str)
2607 return 0;
2608 thash_entries = simple_strtoul(str, &str, 0);
2609 return 1;
2611 __setup("thash_entries=", set_thash_entries);
2613 void __init tcp_init(void)
2615 struct sk_buff *skb = NULL;
2616 unsigned long limit;
2617 int order, i, max_share;
2619 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
2621 tcp_hashinfo.bind_bucket_cachep =
2622 kmem_cache_create("tcp_bind_bucket",
2623 sizeof(struct inet_bind_bucket), 0,
2624 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2626 /* Size and allocate the main established and bind bucket
2627 * hash tables.
2629 * The methodology is similar to that of the buffer cache.
2631 tcp_hashinfo.ehash =
2632 alloc_large_system_hash("TCP established",
2633 sizeof(struct inet_ehash_bucket),
2634 thash_entries,
2635 (num_physpages >= 128 * 1024) ?
2636 13 : 15,
2638 &tcp_hashinfo.ehash_size,
2639 NULL,
2640 thash_entries ? 0 : 512 * 1024);
2641 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2642 for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2643 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2644 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain);
2646 if (inet_ehash_locks_alloc(&tcp_hashinfo))
2647 panic("TCP: failed to alloc ehash_locks");
2648 tcp_hashinfo.bhash =
2649 alloc_large_system_hash("TCP bind",
2650 sizeof(struct inet_bind_hashbucket),
2651 tcp_hashinfo.ehash_size,
2652 (num_physpages >= 128 * 1024) ?
2653 13 : 15,
2655 &tcp_hashinfo.bhash_size,
2656 NULL,
2657 64 * 1024);
2658 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2659 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2660 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2661 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2664 /* Try to be a bit smarter and adjust defaults depending
2665 * on available memory.
2667 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2668 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2669 order++)
2671 if (order >= 4) {
2672 tcp_death_row.sysctl_max_tw_buckets = 180000;
2673 sysctl_tcp_max_orphans = 4096 << (order - 4);
2674 sysctl_max_syn_backlog = 1024;
2675 } else if (order < 3) {
2676 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2677 sysctl_tcp_max_orphans >>= (3 - order);
2678 sysctl_max_syn_backlog = 128;
2681 /* Set the pressure threshold to be a fraction of global memory that
2682 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2683 * memory, with a floor of 128 pages.
2685 limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
2686 limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
2687 limit = max(limit, 128UL);
2688 sysctl_tcp_mem[0] = limit / 4 * 3;
2689 sysctl_tcp_mem[1] = limit;
2690 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
2692 /* Set per-socket limits to no more than 1/128 the pressure threshold */
2693 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2694 max_share = min(4UL*1024*1024, limit);
2696 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
2697 sysctl_tcp_wmem[1] = 16*1024;
2698 sysctl_tcp_wmem[2] = max(64*1024, max_share);
2700 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
2701 sysctl_tcp_rmem[1] = 87380;
2702 sysctl_tcp_rmem[2] = max(87380, max_share);
2704 printk(KERN_INFO "TCP: Hash tables configured "
2705 "(established %d bind %d)\n",
2706 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
2708 tcp_register_congestion_control(&tcp_reno);
2711 EXPORT_SYMBOL(tcp_close);
2712 EXPORT_SYMBOL(tcp_disconnect);
2713 EXPORT_SYMBOL(tcp_getsockopt);
2714 EXPORT_SYMBOL(tcp_ioctl);
2715 EXPORT_SYMBOL(tcp_poll);
2716 EXPORT_SYMBOL(tcp_read_sock);
2717 EXPORT_SYMBOL(tcp_recvmsg);
2718 EXPORT_SYMBOL(tcp_sendmsg);
2719 EXPORT_SYMBOL(tcp_splice_read);
2720 EXPORT_SYMBOL(tcp_sendpage);
2721 EXPORT_SYMBOL(tcp_setsockopt);
2722 EXPORT_SYMBOL(tcp_shutdown);
2723 EXPORT_SYMBOL(tcp_statistics);