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ocfs2: Read support for directories with inline data
[linux-2.6/verdex.git] / net / ipv4 / tcp.c
blob4f322003835dc1886b4202259a91bd641d9139c3
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * Version: $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $
9 *
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>
21 *
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.
209 *
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.
214 *
215 * Description of States:
216 *
217 * TCP_SYN_SENT sent a connection request, waiting for ack
218 *
219 * TCP_SYN_RECV received a connection request, sent ack,
220 * waiting for final ack in three-way handshake.
221 *
222 * TCP_ESTABLISHED connection established
223 *
224 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
225 * transmission of remaining buffered data
226 *
227 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
228 * to shutdown
229 *
230 * TCP_CLOSING both sides have shutdown but we still have
231 * data we have to finish sending
232 *
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)
238 *
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)
242 *
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
246 *
247 * TCP_CLOSE socket is finished
248 */
249
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/random.h>
258 #include <linux/bootmem.h>
259 #include <linux/cache.h>
260 #include <linux/err.h>
261 #include <linux/crypto.h>
262
263 #include <net/icmp.h>
264 #include <net/tcp.h>
265 #include <net/xfrm.h>
266 #include <net/ip.h>
267 #include <net/netdma.h>
268
269 #include <asm/uaccess.h>
270 #include <asm/ioctls.h>
271
272 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
273
274 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly;
275
276 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
277
278 EXPORT_SYMBOL_GPL(tcp_orphan_count);
279
280 int sysctl_tcp_mem[3] __read_mostly;
281 int sysctl_tcp_wmem[3] __read_mostly;
282 int sysctl_tcp_rmem[3] __read_mostly;
283
284 EXPORT_SYMBOL(sysctl_tcp_mem);
285 EXPORT_SYMBOL(sysctl_tcp_rmem);
286 EXPORT_SYMBOL(sysctl_tcp_wmem);
287
288 atomic_t tcp_memory_allocated; /* Current allocated memory. */
289 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
290
291 EXPORT_SYMBOL(tcp_memory_allocated);
292 EXPORT_SYMBOL(tcp_sockets_allocated);
293
294 /*
295 * Pressure flag: try to collapse.
296 * Technical note: it is used by multiple contexts non atomically.
297 * All the sk_stream_mem_schedule() is of this nature: accounting
298 * is strict, actions are advisory and have some latency.
299 */
300 int tcp_memory_pressure __read_mostly;
301
302 EXPORT_SYMBOL(tcp_memory_pressure);
303
304 void tcp_enter_memory_pressure(void)
305 {
306 if (!tcp_memory_pressure) {
307 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
308 tcp_memory_pressure = 1;
309 }
310 }
311
312 EXPORT_SYMBOL(tcp_enter_memory_pressure);
313
314 /*
315 * Wait for a TCP event.
316 *
317 * Note that we don't need to lock the socket, as the upper poll layers
318 * take care of normal races (between the test and the event) and we don't
319 * go look at any of the socket buffers directly.
320 */
321 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
322 {
323 unsigned int mask;
324 struct sock *sk = sock->sk;
325 struct tcp_sock *tp = tcp_sk(sk);
326
327 poll_wait(file, sk->sk_sleep, wait);
328 if (sk->sk_state == TCP_LISTEN)
329 return inet_csk_listen_poll(sk);
330
331 /* Socket is not locked. We are protected from async events
332 by poll logic and correct handling of state changes
333 made by another threads is impossible in any case.
334 */
335
336 mask = 0;
337 if (sk->sk_err)
338 mask = POLLERR;
339
340 /*
341 * POLLHUP is certainly not done right. But poll() doesn't
342 * have a notion of HUP in just one direction, and for a
343 * socket the read side is more interesting.
344 *
345 * Some poll() documentation says that POLLHUP is incompatible
346 * with the POLLOUT/POLLWR flags, so somebody should check this
347 * all. But careful, it tends to be safer to return too many
348 * bits than too few, and you can easily break real applications
349 * if you don't tell them that something has hung up!
350 *
351 * Check-me.
352 *
353 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
354 * our fs/select.c). It means that after we received EOF,
355 * poll always returns immediately, making impossible poll() on write()
356 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
357 * if and only if shutdown has been made in both directions.
358 * Actually, it is interesting to look how Solaris and DUX
359 * solve this dilemma. I would prefer, if PULLHUP were maskable,
360 * then we could set it on SND_SHUTDOWN. BTW examples given
361 * in Stevens' books assume exactly this behaviour, it explains
362 * why PULLHUP is incompatible with POLLOUT. --ANK
363 *
364 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
365 * blocking on fresh not-connected or disconnected socket. --ANK
366 */
367 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
368 mask |= POLLHUP;
369 if (sk->sk_shutdown & RCV_SHUTDOWN)
370 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
371
372 /* Connected? */
373 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
374 /* Potential race condition. If read of tp below will
375 * escape above sk->sk_state, we can be illegally awaken
376 * in SYN_* states. */
377 if ((tp->rcv_nxt != tp->copied_seq) &&
378 (tp->urg_seq != tp->copied_seq ||
379 tp->rcv_nxt != tp->copied_seq + 1 ||
380 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
381 mask |= POLLIN | POLLRDNORM;
382
383 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
384 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
385 mask |= POLLOUT | POLLWRNORM;
386 } else { /* send SIGIO later */
387 set_bit(SOCK_ASYNC_NOSPACE,
388 &sk->sk_socket->flags);
389 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
390
391 /* Race breaker. If space is freed after
392 * wspace test but before the flags are set,
393 * IO signal will be lost.
394 */
395 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
396 mask |= POLLOUT | POLLWRNORM;
397 }
398 }
399
400 if (tp->urg_data & TCP_URG_VALID)
401 mask |= POLLPRI;
402 }
403 return mask;
404 }
405
406 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
407 {
408 struct tcp_sock *tp = tcp_sk(sk);
409 int answ;
410
411 switch (cmd) {
412 case SIOCINQ:
413 if (sk->sk_state == TCP_LISTEN)
414 return -EINVAL;
415
416 lock_sock(sk);
417 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
418 answ = 0;
419 else if (sock_flag(sk, SOCK_URGINLINE) ||
420 !tp->urg_data ||
421 before(tp->urg_seq, tp->copied_seq) ||
422 !before(tp->urg_seq, tp->rcv_nxt)) {
423 answ = tp->rcv_nxt - tp->copied_seq;
424
425 /* Subtract 1, if FIN is in queue. */
426 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
427 answ -=
428 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin;
429 } else
430 answ = tp->urg_seq - tp->copied_seq;
431 release_sock(sk);
432 break;
433 case SIOCATMARK:
434 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
435 break;
436 case SIOCOUTQ:
437 if (sk->sk_state == TCP_LISTEN)
438 return -EINVAL;
439
440 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
441 answ = 0;
442 else
443 answ = tp->write_seq - tp->snd_una;
444 break;
445 default:
446 return -ENOIOCTLCMD;
447 }
448
449 return put_user(answ, (int __user *)arg);
450 }
451
452 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
453 {
454 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
455 tp->pushed_seq = tp->write_seq;
456 }
457
458 static inline int forced_push(struct tcp_sock *tp)
459 {
460 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
461 }
462
463 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
464 {
465 struct tcp_sock *tp = tcp_sk(sk);
466 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
467
468 skb->csum = 0;
469 tcb->seq = tcb->end_seq = tp->write_seq;
470 tcb->flags = TCPCB_FLAG_ACK;
471 tcb->sacked = 0;
472 skb_header_release(skb);
473 tcp_add_write_queue_tail(sk, skb);
474 sk_charge_skb(sk, skb);
475 if (tp->nonagle & TCP_NAGLE_PUSH)
476 tp->nonagle &= ~TCP_NAGLE_PUSH;
477 }
478
479 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
480 struct sk_buff *skb)
481 {
482 if (flags & MSG_OOB) {
483 tp->urg_mode = 1;
484 tp->snd_up = tp->write_seq;
485 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
486 }
487 }
488
489 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
490 int nonagle)
491 {
492 struct tcp_sock *tp = tcp_sk(sk);
493
494 if (tcp_send_head(sk)) {
495 struct sk_buff *skb = tcp_write_queue_tail(sk);
496 if (!(flags & MSG_MORE) || forced_push(tp))
497 tcp_mark_push(tp, skb);
498 tcp_mark_urg(tp, flags, skb);
499 __tcp_push_pending_frames(sk, mss_now,
500 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
501 }
502 }
503
504 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
505 size_t psize, int flags)
506 {
507 struct tcp_sock *tp = tcp_sk(sk);
508 int mss_now, size_goal;
509 int err;
510 ssize_t copied;
511 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
512
513 /* Wait for a connection to finish. */
514 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
515 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
516 goto out_err;
517
518 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
519
520 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
521 size_goal = tp->xmit_size_goal;
522 copied = 0;
523
524 err = -EPIPE;
525 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
526 goto do_error;
527
528 while (psize > 0) {
529 struct sk_buff *skb = tcp_write_queue_tail(sk);
530 struct page *page = pages[poffset / PAGE_SIZE];
531 int copy, i, can_coalesce;
532 int offset = poffset % PAGE_SIZE;
533 int size = min_t(size_t, psize, PAGE_SIZE - offset);
534
535 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
536 new_segment:
537 if (!sk_stream_memory_free(sk))
538 goto wait_for_sndbuf;
539
540 skb = sk_stream_alloc_pskb(sk, 0, 0,
541 sk->sk_allocation);
542 if (!skb)
543 goto wait_for_memory;
544
545 skb_entail(sk, skb);
546 copy = size_goal;
547 }
548
549 if (copy > size)
550 copy = size;
551
552 i = skb_shinfo(skb)->nr_frags;
553 can_coalesce = skb_can_coalesce(skb, i, page, offset);
554 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
555 tcp_mark_push(tp, skb);
556 goto new_segment;
557 }
558 if (!sk_stream_wmem_schedule(sk, copy))
559 goto wait_for_memory;
560
561 if (can_coalesce) {
562 skb_shinfo(skb)->frags[i - 1].size += copy;
563 } else {
564 get_page(page);
565 skb_fill_page_desc(skb, i, page, offset, copy);
566 }
567
568 skb->len += copy;
569 skb->data_len += copy;
570 skb->truesize += copy;
571 sk->sk_wmem_queued += copy;
572 sk->sk_forward_alloc -= copy;
573 skb->ip_summed = CHECKSUM_PARTIAL;
574 tp->write_seq += copy;
575 TCP_SKB_CB(skb)->end_seq += copy;
576 skb_shinfo(skb)->gso_segs = 0;
577
578 if (!copied)
579 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
580
581 copied += copy;
582 poffset += copy;
583 if (!(psize -= copy))
584 goto out;
585
586 if (skb->len < mss_now || (flags & MSG_OOB))
587 continue;
588
589 if (forced_push(tp)) {
590 tcp_mark_push(tp, skb);
591 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
592 } else if (skb == tcp_send_head(sk))
593 tcp_push_one(sk, mss_now);
594 continue;
595
596 wait_for_sndbuf:
597 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
598 wait_for_memory:
599 if (copied)
600 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
601
602 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
603 goto do_error;
604
605 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
606 size_goal = tp->xmit_size_goal;
607 }
608
609 out:
610 if (copied)
611 tcp_push(sk, flags, mss_now, tp->nonagle);
612 return copied;
613
614 do_error:
615 if (copied)
616 goto out;
617 out_err:
618 return sk_stream_error(sk, flags, err);
619 }
620
621 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
622 size_t size, int flags)
623 {
624 ssize_t res;
625 struct sock *sk = sock->sk;
626
627 if (!(sk->sk_route_caps & NETIF_F_SG) ||
628 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
629 return sock_no_sendpage(sock, page, offset, size, flags);
630
631 lock_sock(sk);
632 TCP_CHECK_TIMER(sk);
633 res = do_tcp_sendpages(sk, &page, offset, size, flags);
634 TCP_CHECK_TIMER(sk);
635 release_sock(sk);
636 return res;
637 }
638
639 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
640 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
641
642 static inline int select_size(struct sock *sk)
643 {
644 struct tcp_sock *tp = tcp_sk(sk);
645 int tmp = tp->mss_cache;
646
647 if (sk->sk_route_caps & NETIF_F_SG) {
648 if (sk_can_gso(sk))
649 tmp = 0;
650 else {
651 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
652
653 if (tmp >= pgbreak &&
654 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
655 tmp = pgbreak;
656 }
657 }
658
659 return tmp;
660 }
661
662 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
663 size_t size)
664 {
665 struct sock *sk = sock->sk;
666 struct iovec *iov;
667 struct tcp_sock *tp = tcp_sk(sk);
668 struct sk_buff *skb;
669 int iovlen, flags;
670 int mss_now, size_goal;
671 int err, copied;
672 long timeo;
673
674 lock_sock(sk);
675 TCP_CHECK_TIMER(sk);
676
677 flags = msg->msg_flags;
678 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
679
680 /* Wait for a connection to finish. */
681 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
682 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
683 goto out_err;
684
685 /* This should be in poll */
686 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
687
688 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
689 size_goal = tp->xmit_size_goal;
690
691 /* Ok commence sending. */
692 iovlen = msg->msg_iovlen;
693 iov = msg->msg_iov;
694 copied = 0;
695
696 err = -EPIPE;
697 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
698 goto do_error;
699
700 while (--iovlen >= 0) {
701 int seglen = iov->iov_len;
702 unsigned char __user *from = iov->iov_base;
703
704 iov++;
705
706 while (seglen > 0) {
707 int copy;
708
709 skb = tcp_write_queue_tail(sk);
710
711 if (!tcp_send_head(sk) ||
712 (copy = size_goal - skb->len) <= 0) {
713
714 new_segment:
715 /* Allocate new segment. If the interface is SG,
716 * allocate skb fitting to single page.
717 */
718 if (!sk_stream_memory_free(sk))
719 goto wait_for_sndbuf;
720
721 skb = sk_stream_alloc_pskb(sk, select_size(sk),
722 0, sk->sk_allocation);
723 if (!skb)
724 goto wait_for_memory;
725
726 /*
727 * Check whether we can use HW checksum.
728 */
729 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
730 skb->ip_summed = CHECKSUM_PARTIAL;
731
732 skb_entail(sk, skb);
733 copy = size_goal;
734 }
735
736 /* Try to append data to the end of skb. */
737 if (copy > seglen)
738 copy = seglen;
739
740 /* Where to copy to? */
741 if (skb_tailroom(skb) > 0) {
742 /* We have some space in skb head. Superb! */
743 if (copy > skb_tailroom(skb))
744 copy = skb_tailroom(skb);
745 if ((err = skb_add_data(skb, from, copy)) != 0)
746 goto do_fault;
747 } else {
748 int merge = 0;
749 int i = skb_shinfo(skb)->nr_frags;
750 struct page *page = TCP_PAGE(sk);
751 int off = TCP_OFF(sk);
752
753 if (skb_can_coalesce(skb, i, page, off) &&
754 off != PAGE_SIZE) {
755 /* We can extend the last page
756 * fragment. */
757 merge = 1;
758 } else if (i == MAX_SKB_FRAGS ||
759 (!i &&
760 !(sk->sk_route_caps & NETIF_F_SG))) {
761 /* Need to add new fragment and cannot
762 * do this because interface is non-SG,
763 * or because all the page slots are
764 * busy. */
765 tcp_mark_push(tp, skb);
766 goto new_segment;
767 } else if (page) {
768 if (off == PAGE_SIZE) {
769 put_page(page);
770 TCP_PAGE(sk) = page = NULL;
771 off = 0;
772 }
773 } else
774 off = 0;
775
776 if (copy > PAGE_SIZE - off)
777 copy = PAGE_SIZE - off;
778
779 if (!sk_stream_wmem_schedule(sk, copy))
780 goto wait_for_memory;
781
782 if (!page) {
783 /* Allocate new cache page. */
784 if (!(page = sk_stream_alloc_page(sk)))
785 goto wait_for_memory;
786 }
787
788 /* Time to copy data. We are close to
789 * the end! */
790 err = skb_copy_to_page(sk, from, skb, page,
791 off, copy);
792 if (err) {
793 /* If this page was new, give it to the
794 * socket so it does not get leaked.
795 */
796 if (!TCP_PAGE(sk)) {
797 TCP_PAGE(sk) = page;
798 TCP_OFF(sk) = 0;
799 }
800 goto do_error;
801 }
802
803 /* Update the skb. */
804 if (merge) {
805 skb_shinfo(skb)->frags[i - 1].size +=
806 copy;
807 } else {
808 skb_fill_page_desc(skb, i, page, off, copy);
809 if (TCP_PAGE(sk)) {
810 get_page(page);
811 } else if (off + copy < PAGE_SIZE) {
812 get_page(page);
813 TCP_PAGE(sk) = page;
814 }
815 }
816
817 TCP_OFF(sk) = off + copy;
818 }
819
820 if (!copied)
821 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
822
823 tp->write_seq += copy;
824 TCP_SKB_CB(skb)->end_seq += copy;
825 skb_shinfo(skb)->gso_segs = 0;
826
827 from += copy;
828 copied += copy;
829 if ((seglen -= copy) == 0 && iovlen == 0)
830 goto out;
831
832 if (skb->len < mss_now || (flags & MSG_OOB))
833 continue;
834
835 if (forced_push(tp)) {
836 tcp_mark_push(tp, skb);
837 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
838 } else if (skb == tcp_send_head(sk))
839 tcp_push_one(sk, mss_now);
840 continue;
841
842 wait_for_sndbuf:
843 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
844 wait_for_memory:
845 if (copied)
846 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
847
848 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
849 goto do_error;
850
851 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
852 size_goal = tp->xmit_size_goal;
853 }
854 }
855
856 out:
857 if (copied)
858 tcp_push(sk, flags, mss_now, tp->nonagle);
859 TCP_CHECK_TIMER(sk);
860 release_sock(sk);
861 return copied;
862
863 do_fault:
864 if (!skb->len) {
865 tcp_unlink_write_queue(skb, sk);
866 /* It is the one place in all of TCP, except connection
867 * reset, where we can be unlinking the send_head.
868 */
869 tcp_check_send_head(sk, skb);
870 sk_stream_free_skb(sk, skb);
871 }
872
873 do_error:
874 if (copied)
875 goto out;
876 out_err:
877 err = sk_stream_error(sk, flags, err);
878 TCP_CHECK_TIMER(sk);
879 release_sock(sk);
880 return err;
881 }
882
883 /*
884 * Handle reading urgent data. BSD has very simple semantics for
885 * this, no blocking and very strange errors 8)
886 */
887
888 static int tcp_recv_urg(struct sock *sk, long timeo,
889 struct msghdr *msg, int len, int flags,
890 int *addr_len)
891 {
892 struct tcp_sock *tp = tcp_sk(sk);
893
894 /* No URG data to read. */
895 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
896 tp->urg_data == TCP_URG_READ)
897 return -EINVAL; /* Yes this is right ! */
898
899 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
900 return -ENOTCONN;
901
902 if (tp->urg_data & TCP_URG_VALID) {
903 int err = 0;
904 char c = tp->urg_data;
905
906 if (!(flags & MSG_PEEK))
907 tp->urg_data = TCP_URG_READ;
908
909 /* Read urgent data. */
910 msg->msg_flags |= MSG_OOB;
911
912 if (len > 0) {
913 if (!(flags & MSG_TRUNC))
914 err = memcpy_toiovec(msg->msg_iov, &c, 1);
915 len = 1;
916 } else
917 msg->msg_flags |= MSG_TRUNC;
918
919 return err ? -EFAULT : len;
920 }
921
922 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
923 return 0;
924
925 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
926 * the available implementations agree in this case:
927 * this call should never block, independent of the
928 * blocking state of the socket.
929 * Mike <pall@rz.uni-karlsruhe.de>
930 */
931 return -EAGAIN;
932 }
933
934 /* Clean up the receive buffer for full frames taken by the user,
935 * then send an ACK if necessary. COPIED is the number of bytes
936 * tcp_recvmsg has given to the user so far, it speeds up the
937 * calculation of whether or not we must ACK for the sake of
938 * a window update.
939 */
940 void tcp_cleanup_rbuf(struct sock *sk, int copied)
941 {
942 struct tcp_sock *tp = tcp_sk(sk);
943 int time_to_ack = 0;
944
945 #if TCP_DEBUG
946 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
947
948 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
949 #endif
950
951 if (inet_csk_ack_scheduled(sk)) {
952 const struct inet_connection_sock *icsk = inet_csk(sk);
953 /* Delayed ACKs frequently hit locked sockets during bulk
954 * receive. */
955 if (icsk->icsk_ack.blocked ||
956 /* Once-per-two-segments ACK was not sent by tcp_input.c */
957 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
958 /*
959 * If this read emptied read buffer, we send ACK, if
960 * connection is not bidirectional, user drained
961 * receive buffer and there was a small segment
962 * in queue.
963 */
964 (copied > 0 &&
965 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
966 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
967 !icsk->icsk_ack.pingpong)) &&
968 !atomic_read(&sk->sk_rmem_alloc)))
969 time_to_ack = 1;
970 }
971
972 /* We send an ACK if we can now advertise a non-zero window
973 * which has been raised "significantly".
974 *
975 * Even if window raised up to infinity, do not send window open ACK
976 * in states, where we will not receive more. It is useless.
977 */
978 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
979 __u32 rcv_window_now = tcp_receive_window(tp);
980
981 /* Optimize, __tcp_select_window() is not cheap. */
982 if (2*rcv_window_now <= tp->window_clamp) {
983 __u32 new_window = __tcp_select_window(sk);
984
985 /* Send ACK now, if this read freed lots of space
986 * in our buffer. Certainly, new_window is new window.
987 * We can advertise it now, if it is not less than current one.
988 * "Lots" means "at least twice" here.
989 */
990 if (new_window && new_window >= 2 * rcv_window_now)
991 time_to_ack = 1;
992 }
993 }
994 if (time_to_ack)
995 tcp_send_ack(sk);
996 }
997
998 static void tcp_prequeue_process(struct sock *sk)
999 {
1000 struct sk_buff *skb;
1001 struct tcp_sock *tp = tcp_sk(sk);
1002
1003 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
1004
1005 /* RX process wants to run with disabled BHs, though it is not
1006 * necessary */
1007 local_bh_disable();
1008 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1009 sk->sk_backlog_rcv(sk, skb);
1010 local_bh_enable();
1011
1012 /* Clear memory counter. */
1013 tp->ucopy.memory = 0;
1014 }
1015
1016 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1017 {
1018 struct sk_buff *skb;
1019 u32 offset;
1020
1021 skb_queue_walk(&sk->sk_receive_queue, skb) {
1022 offset = seq - TCP_SKB_CB(skb)->seq;
1023 if (tcp_hdr(skb)->syn)
1024 offset--;
1025 if (offset < skb->len || tcp_hdr(skb)->fin) {
1026 *off = offset;
1027 return skb;
1028 }
1029 }
1030 return NULL;
1031 }
1032
1033 /*
1034 * This routine provides an alternative to tcp_recvmsg() for routines
1035 * that would like to handle copying from skbuffs directly in 'sendfile'
1036 * fashion.
1037 * Note:
1038 * - It is assumed that the socket was locked by the caller.
1039 * - The routine does not block.
1040 * - At present, there is no support for reading OOB data
1041 * or for 'peeking' the socket using this routine
1042 * (although both would be easy to implement).
1043 */
1044 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1045 sk_read_actor_t recv_actor)
1046 {
1047 struct sk_buff *skb;
1048 struct tcp_sock *tp = tcp_sk(sk);
1049 u32 seq = tp->copied_seq;
1050 u32 offset;
1051 int copied = 0;
1052
1053 if (sk->sk_state == TCP_LISTEN)
1054 return -ENOTCONN;
1055 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1056 if (offset < skb->len) {
1057 size_t used, len;
1058
1059 len = skb->len - offset;
1060 /* Stop reading if we hit a patch of urgent data */
1061 if (tp->urg_data) {
1062 u32 urg_offset = tp->urg_seq - seq;
1063 if (urg_offset < len)
1064 len = urg_offset;
1065 if (!len)
1066 break;
1067 }
1068 used = recv_actor(desc, skb, offset, len);
1069 if (used < 0) {
1070 if (!copied)
1071 copied = used;
1072 break;
1073 } else if (used <= len) {
1074 seq += used;
1075 copied += used;
1076 offset += used;
1077 }
1078 if (offset != skb->len)
1079 break;
1080 }
1081 if (tcp_hdr(skb)->fin) {
1082 sk_eat_skb(sk, skb, 0);
1083 ++seq;
1084 break;
1085 }
1086 sk_eat_skb(sk, skb, 0);
1087 if (!desc->count)
1088 break;
1089 }
1090 tp->copied_seq = seq;
1091
1092 tcp_rcv_space_adjust(sk);
1093
1094 /* Clean up data we have read: This will do ACK frames. */
1095 if (copied > 0)
1096 tcp_cleanup_rbuf(sk, copied);
1097 return copied;
1098 }
1099
1100 /*
1101 * This routine copies from a sock struct into the user buffer.
1102 *
1103 * Technical note: in 2.3 we work on _locked_ socket, so that
1104 * tricks with *seq access order and skb->users are not required.
1105 * Probably, code can be easily improved even more.
1106 */
1107
1108 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1109 size_t len, int nonblock, int flags, int *addr_len)
1110 {
1111 struct tcp_sock *tp = tcp_sk(sk);
1112 int copied = 0;
1113 u32 peek_seq;
1114 u32 *seq;
1115 unsigned long used;
1116 int err;
1117 int target; /* Read at least this many bytes */
1118 long timeo;
1119 struct task_struct *user_recv = NULL;
1120 int copied_early = 0;
1121 struct sk_buff *skb;
1122
1123 lock_sock(sk);
1124
1125 TCP_CHECK_TIMER(sk);
1126
1127 err = -ENOTCONN;
1128 if (sk->sk_state == TCP_LISTEN)
1129 goto out;
1130
1131 timeo = sock_rcvtimeo(sk, nonblock);
1132
1133 /* Urgent data needs to be handled specially. */
1134 if (flags & MSG_OOB)
1135 goto recv_urg;
1136
1137 seq = &tp->copied_seq;
1138 if (flags & MSG_PEEK) {
1139 peek_seq = tp->copied_seq;
1140 seq = &peek_seq;
1141 }
1142
1143 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1144
1145 #ifdef CONFIG_NET_DMA
1146 tp->ucopy.dma_chan = NULL;
1147 preempt_disable();
1148 skb = skb_peek_tail(&sk->sk_receive_queue);
1149 {
1150 int available = 0;
1151
1152 if (skb)
1153 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1154 if ((available < target) &&
1155 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1156 !sysctl_tcp_low_latency &&
1157 __get_cpu_var(softnet_data).net_dma) {
1158 preempt_enable_no_resched();
1159 tp->ucopy.pinned_list =
1160 dma_pin_iovec_pages(msg->msg_iov, len);
1161 } else {
1162 preempt_enable_no_resched();
1163 }
1164 }
1165 #endif
1166
1167 do {
1168 u32 offset;
1169
1170 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1171 if (tp->urg_data && tp->urg_seq == *seq) {
1172 if (copied)
1173 break;
1174 if (signal_pending(current)) {
1175 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1176 break;
1177 }
1178 }
1179
1180 /* Next get a buffer. */
1181
1182 skb = skb_peek(&sk->sk_receive_queue);
1183 do {
1184 if (!skb)
1185 break;
1186
1187 /* Now that we have two receive queues this
1188 * shouldn't happen.
1189 */
1190 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1191 printk(KERN_INFO "recvmsg bug: copied %X "
1192 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1193 break;
1194 }
1195 offset = *seq - TCP_SKB_CB(skb)->seq;
1196 if (tcp_hdr(skb)->syn)
1197 offset--;
1198 if (offset < skb->len)
1199 goto found_ok_skb;
1200 if (tcp_hdr(skb)->fin)
1201 goto found_fin_ok;
1202 BUG_TRAP(flags & MSG_PEEK);
1203 skb = skb->next;
1204 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1205
1206 /* Well, if we have backlog, try to process it now yet. */
1207
1208 if (copied >= target && !sk->sk_backlog.tail)
1209 break;
1210
1211 if (copied) {
1212 if (sk->sk_err ||
1213 sk->sk_state == TCP_CLOSE ||
1214 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1215 !timeo ||
1216 signal_pending(current) ||
1217 (flags & MSG_PEEK))
1218 break;
1219 } else {
1220 if (sock_flag(sk, SOCK_DONE))
1221 break;
1222
1223 if (sk->sk_err) {
1224 copied = sock_error(sk);
1225 break;
1226 }
1227
1228 if (sk->sk_shutdown & RCV_SHUTDOWN)
1229 break;
1230
1231 if (sk->sk_state == TCP_CLOSE) {
1232 if (!sock_flag(sk, SOCK_DONE)) {
1233 /* This occurs when user tries to read
1234 * from never connected socket.
1235 */
1236 copied = -ENOTCONN;
1237 break;
1238 }
1239 break;
1240 }
1241
1242 if (!timeo) {
1243 copied = -EAGAIN;
1244 break;
1245 }
1246
1247 if (signal_pending(current)) {
1248 copied = sock_intr_errno(timeo);
1249 break;
1250 }
1251 }
1252
1253 tcp_cleanup_rbuf(sk, copied);
1254
1255 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1256 /* Install new reader */
1257 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1258 user_recv = current;
1259 tp->ucopy.task = user_recv;
1260 tp->ucopy.iov = msg->msg_iov;
1261 }
1262
1263 tp->ucopy.len = len;
1264
1265 BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1266 (flags & (MSG_PEEK | MSG_TRUNC)));
1267
1268 /* Ugly... If prequeue is not empty, we have to
1269 * process it before releasing socket, otherwise
1270 * order will be broken at second iteration.
1271 * More elegant solution is required!!!
1272 *
1273 * Look: we have the following (pseudo)queues:
1274 *
1275 * 1. packets in flight
1276 * 2. backlog
1277 * 3. prequeue
1278 * 4. receive_queue
1279 *
1280 * Each queue can be processed only if the next ones
1281 * are empty. At this point we have empty receive_queue.
1282 * But prequeue _can_ be not empty after 2nd iteration,
1283 * when we jumped to start of loop because backlog
1284 * processing added something to receive_queue.
1285 * We cannot release_sock(), because backlog contains
1286 * packets arrived _after_ prequeued ones.
1287 *
1288 * Shortly, algorithm is clear --- to process all
1289 * the queues in order. We could make it more directly,
1290 * requeueing packets from backlog to prequeue, if
1291 * is not empty. It is more elegant, but eats cycles,
1292 * unfortunately.
1293 */
1294 if (!skb_queue_empty(&tp->ucopy.prequeue))
1295 goto do_prequeue;
1296
1297 /* __ Set realtime policy in scheduler __ */
1298 }
1299
1300 if (copied >= target) {
1301 /* Do not sleep, just process backlog. */
1302 release_sock(sk);
1303 lock_sock(sk);
1304 } else
1305 sk_wait_data(sk, &timeo);
1306
1307 #ifdef CONFIG_NET_DMA
1308 tp->ucopy.wakeup = 0;
1309 #endif
1310
1311 if (user_recv) {
1312 int chunk;
1313
1314 /* __ Restore normal policy in scheduler __ */
1315
1316 if ((chunk = len - tp->ucopy.len) != 0) {
1317 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1318 len -= chunk;
1319 copied += chunk;
1320 }
1321
1322 if (tp->rcv_nxt == tp->copied_seq &&
1323 !skb_queue_empty(&tp->ucopy.prequeue)) {
1324 do_prequeue:
1325 tcp_prequeue_process(sk);
1326
1327 if ((chunk = len - tp->ucopy.len) != 0) {
1328 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1329 len -= chunk;
1330 copied += chunk;
1331 }
1332 }
1333 }
1334 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1335 if (net_ratelimit())
1336 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1337 current->comm, current->pid);
1338 peek_seq = tp->copied_seq;
1339 }
1340 continue;
1341
1342 found_ok_skb:
1343 /* Ok so how much can we use? */
1344 used = skb->len - offset;
1345 if (len < used)
1346 used = len;
1347
1348 /* Do we have urgent data here? */
1349 if (tp->urg_data) {
1350 u32 urg_offset = tp->urg_seq - *seq;
1351 if (urg_offset < used) {
1352 if (!urg_offset) {
1353 if (!sock_flag(sk, SOCK_URGINLINE)) {
1354 ++*seq;
1355 offset++;
1356 used--;
1357 if (!used)
1358 goto skip_copy;
1359 }
1360 } else
1361 used = urg_offset;
1362 }
1363 }
1364
1365 if (!(flags & MSG_TRUNC)) {
1366 #ifdef CONFIG_NET_DMA
1367 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1368 tp->ucopy.dma_chan = get_softnet_dma();
1369
1370 if (tp->ucopy.dma_chan) {
1371 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1372 tp->ucopy.dma_chan, skb, offset,
1373 msg->msg_iov, used,
1374 tp->ucopy.pinned_list);
1375
1376 if (tp->ucopy.dma_cookie < 0) {
1377
1378 printk(KERN_ALERT "dma_cookie < 0\n");
1379
1380 /* Exception. Bailout! */
1381 if (!copied)
1382 copied = -EFAULT;
1383 break;
1384 }
1385 if ((offset + used) == skb->len)
1386 copied_early = 1;
1387
1388 } else
1389 #endif
1390 {
1391 err = skb_copy_datagram_iovec(skb, offset,
1392 msg->msg_iov, used);
1393 if (err) {
1394 /* Exception. Bailout! */
1395 if (!copied)
1396 copied = -EFAULT;
1397 break;
1398 }
1399 }
1400 }
1401
1402 *seq += used;
1403 copied += used;
1404 len -= used;
1405
1406 tcp_rcv_space_adjust(sk);
1407
1408 skip_copy:
1409 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1410 tp->urg_data = 0;
1411 tcp_fast_path_check(sk);
1412 }
1413 if (used + offset < skb->len)
1414 continue;
1415
1416 if (tcp_hdr(skb)->fin)
1417 goto found_fin_ok;
1418 if (!(flags & MSG_PEEK)) {
1419 sk_eat_skb(sk, skb, copied_early);
1420 copied_early = 0;
1421 }
1422 continue;
1423
1424 found_fin_ok:
1425 /* Process the FIN. */
1426 ++*seq;
1427 if (!(flags & MSG_PEEK)) {
1428 sk_eat_skb(sk, skb, copied_early);
1429 copied_early = 0;
1430 }
1431 break;
1432 } while (len > 0);
1433
1434 if (user_recv) {
1435 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1436 int chunk;
1437
1438 tp->ucopy.len = copied > 0 ? len : 0;
1439
1440 tcp_prequeue_process(sk);
1441
1442 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1443 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1444 len -= chunk;
1445 copied += chunk;
1446 }
1447 }
1448
1449 tp->ucopy.task = NULL;
1450 tp->ucopy.len = 0;
1451 }
1452
1453 #ifdef CONFIG_NET_DMA
1454 if (tp->ucopy.dma_chan) {
1455 dma_cookie_t done, used;
1456
1457 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1458
1459 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1460 tp->ucopy.dma_cookie, &done,
1461 &used) == DMA_IN_PROGRESS) {
1462 /* do partial cleanup of sk_async_wait_queue */
1463 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1464 (dma_async_is_complete(skb->dma_cookie, done,
1465 used) == DMA_SUCCESS)) {
1466 __skb_dequeue(&sk->sk_async_wait_queue);
1467 kfree_skb(skb);
1468 }
1469 }
1470
1471 /* Safe to free early-copied skbs now */
1472 __skb_queue_purge(&sk->sk_async_wait_queue);
1473 dma_chan_put(tp->ucopy.dma_chan);
1474 tp->ucopy.dma_chan = NULL;
1475 }
1476 if (tp->ucopy.pinned_list) {
1477 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1478 tp->ucopy.pinned_list = NULL;
1479 }
1480 #endif
1481
1482 /* According to UNIX98, msg_name/msg_namelen are ignored
1483 * on connected socket. I was just happy when found this 8) --ANK
1484 */
1485
1486 /* Clean up data we have read: This will do ACK frames. */
1487 tcp_cleanup_rbuf(sk, copied);
1488
1489 TCP_CHECK_TIMER(sk);
1490 release_sock(sk);
1491 return copied;
1492
1493 out:
1494 TCP_CHECK_TIMER(sk);
1495 release_sock(sk);
1496 return err;
1497
1498 recv_urg:
1499 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1500 goto out;
1501 }
1502
1503 /*
1504 * State processing on a close. This implements the state shift for
1505 * sending our FIN frame. Note that we only send a FIN for some
1506 * states. A shutdown() may have already sent the FIN, or we may be
1507 * closed.
1508 */
1509
1510 static const unsigned char new_state[16] = {
1511 /* current state: new state: action: */
1512 /* (Invalid) */ TCP_CLOSE,
1513 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1514 /* TCP_SYN_SENT */ TCP_CLOSE,
1515 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1516 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1517 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1518 /* TCP_TIME_WAIT */ TCP_CLOSE,
1519 /* TCP_CLOSE */ TCP_CLOSE,
1520 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1521 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1522 /* TCP_LISTEN */ TCP_CLOSE,
1523 /* TCP_CLOSING */ TCP_CLOSING,
1524 };
1525
1526 static int tcp_close_state(struct sock *sk)
1527 {
1528 int next = (int)new_state[sk->sk_state];
1529 int ns = next & TCP_STATE_MASK;
1530
1531 tcp_set_state(sk, ns);
1532
1533 return next & TCP_ACTION_FIN;
1534 }
1535
1536 /*
1537 * Shutdown the sending side of a connection. Much like close except
1538 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1539 */
1540
1541 void tcp_shutdown(struct sock *sk, int how)
1542 {
1543 /* We need to grab some memory, and put together a FIN,
1544 * and then put it into the queue to be sent.
1545 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1546 */
1547 if (!(how & SEND_SHUTDOWN))
1548 return;
1549
1550 /* If we've already sent a FIN, or it's a closed state, skip this. */
1551 if ((1 << sk->sk_state) &
1552 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1553 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1554 /* Clear out any half completed packets. FIN if needed. */
1555 if (tcp_close_state(sk))
1556 tcp_send_fin(sk);
1557 }
1558 }
1559
1560 void tcp_close(struct sock *sk, long timeout)
1561 {
1562 struct sk_buff *skb;
1563 int data_was_unread = 0;
1564 int state;
1565
1566 lock_sock(sk);
1567 sk->sk_shutdown = SHUTDOWN_MASK;
1568
1569 if (sk->sk_state == TCP_LISTEN) {
1570 tcp_set_state(sk, TCP_CLOSE);
1571
1572 /* Special case. */
1573 inet_csk_listen_stop(sk);
1574
1575 goto adjudge_to_death;
1576 }
1577
1578 /* We need to flush the recv. buffs. We do this only on the
1579 * descriptor close, not protocol-sourced closes, because the
1580 * reader process may not have drained the data yet!
1581 */
1582 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1583 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1584 tcp_hdr(skb)->fin;
1585 data_was_unread += len;
1586 __kfree_skb(skb);
1587 }
1588
1589 sk_stream_mem_reclaim(sk);
1590
1591 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1592 * data was lost. To witness the awful effects of the old behavior of
1593 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1594 * GET in an FTP client, suspend the process, wait for the client to
1595 * advertise a zero window, then kill -9 the FTP client, wheee...
1596 * Note: timeout is always zero in such a case.
1597 */
1598 if (data_was_unread) {
1599 /* Unread data was tossed, zap the connection. */
1600 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1601 tcp_set_state(sk, TCP_CLOSE);
1602 tcp_send_active_reset(sk, GFP_KERNEL);
1603 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1604 /* Check zero linger _after_ checking for unread data. */
1605 sk->sk_prot->disconnect(sk, 0);
1606 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1607 } else if (tcp_close_state(sk)) {
1608 /* We FIN if the application ate all the data before
1609 * zapping the connection.
1610 */
1611
1612 /* RED-PEN. Formally speaking, we have broken TCP state
1613 * machine. State transitions:
1614 *
1615 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1616 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1617 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1618 *
1619 * are legal only when FIN has been sent (i.e. in window),
1620 * rather than queued out of window. Purists blame.
1621 *
1622 * F.e. "RFC state" is ESTABLISHED,
1623 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1624 *
1625 * The visible declinations are that sometimes
1626 * we enter time-wait state, when it is not required really
1627 * (harmless), do not send active resets, when they are
1628 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1629 * they look as CLOSING or LAST_ACK for Linux)
1630 * Probably, I missed some more holelets.
1631 * --ANK
1632 */
1633 tcp_send_fin(sk);
1634 }
1635
1636 sk_stream_wait_close(sk, timeout);
1637
1638 adjudge_to_death:
1639 state = sk->sk_state;
1640 sock_hold(sk);
1641 sock_orphan(sk);
1642 atomic_inc(sk->sk_prot->orphan_count);
1643
1644 /* It is the last release_sock in its life. It will remove backlog. */
1645 release_sock(sk);
1646
1647
1648 /* Now socket is owned by kernel and we acquire BH lock
1649 to finish close. No need to check for user refs.
1650 */
1651 local_bh_disable();
1652 bh_lock_sock(sk);
1653 BUG_TRAP(!sock_owned_by_user(sk));
1654
1655 /* Have we already been destroyed by a softirq or backlog? */
1656 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1657 goto out;
1658
1659 /* This is a (useful) BSD violating of the RFC. There is a
1660 * problem with TCP as specified in that the other end could
1661 * keep a socket open forever with no application left this end.
1662 * We use a 3 minute timeout (about the same as BSD) then kill
1663 * our end. If they send after that then tough - BUT: long enough
1664 * that we won't make the old 4*rto = almost no time - whoops
1665 * reset mistake.
1666 *
1667 * Nope, it was not mistake. It is really desired behaviour
1668 * f.e. on http servers, when such sockets are useless, but
1669 * consume significant resources. Let's do it with special
1670 * linger2 option. --ANK
1671 */
1672
1673 if (sk->sk_state == TCP_FIN_WAIT2) {
1674 struct tcp_sock *tp = tcp_sk(sk);
1675 if (tp->linger2 < 0) {
1676 tcp_set_state(sk, TCP_CLOSE);
1677 tcp_send_active_reset(sk, GFP_ATOMIC);
1678 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1679 } else {
1680 const int tmo = tcp_fin_time(sk);
1681
1682 if (tmo > TCP_TIMEWAIT_LEN) {
1683 inet_csk_reset_keepalive_timer(sk,
1684 tmo - TCP_TIMEWAIT_LEN);
1685 } else {
1686 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1687 goto out;
1688 }
1689 }
1690 }
1691 if (sk->sk_state != TCP_CLOSE) {
1692 sk_stream_mem_reclaim(sk);
1693 if (tcp_too_many_orphans(sk,
1694 atomic_read(sk->sk_prot->orphan_count))) {
1695 if (net_ratelimit())
1696 printk(KERN_INFO "TCP: too many of orphaned "
1697 "sockets\n");
1698 tcp_set_state(sk, TCP_CLOSE);
1699 tcp_send_active_reset(sk, GFP_ATOMIC);
1700 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1701 }
1702 }
1703
1704 if (sk->sk_state == TCP_CLOSE)
1705 inet_csk_destroy_sock(sk);
1706 /* Otherwise, socket is reprieved until protocol close. */
1707
1708 out:
1709 bh_unlock_sock(sk);
1710 local_bh_enable();
1711 sock_put(sk);
1712 }
1713
1714 /* These states need RST on ABORT according to RFC793 */
1715
1716 static inline int tcp_need_reset(int state)
1717 {
1718 return (1 << state) &
1719 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1720 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1721 }
1722
1723 int tcp_disconnect(struct sock *sk, int flags)
1724 {
1725 struct inet_sock *inet = inet_sk(sk);
1726 struct inet_connection_sock *icsk = inet_csk(sk);
1727 struct tcp_sock *tp = tcp_sk(sk);
1728 int err = 0;
1729 int old_state = sk->sk_state;
1730
1731 if (old_state != TCP_CLOSE)
1732 tcp_set_state(sk, TCP_CLOSE);
1733
1734 /* ABORT function of RFC793 */
1735 if (old_state == TCP_LISTEN) {
1736 inet_csk_listen_stop(sk);
1737 } else if (tcp_need_reset(old_state) ||
1738 (tp->snd_nxt != tp->write_seq &&
1739 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1740 /* The last check adjusts for discrepancy of Linux wrt. RFC
1741 * states
1742 */
1743 tcp_send_active_reset(sk, gfp_any());
1744 sk->sk_err = ECONNRESET;
1745 } else if (old_state == TCP_SYN_SENT)
1746 sk->sk_err = ECONNRESET;
1747
1748 tcp_clear_xmit_timers(sk);
1749 __skb_queue_purge(&sk->sk_receive_queue);
1750 tcp_write_queue_purge(sk);
1751 __skb_queue_purge(&tp->out_of_order_queue);
1752 #ifdef CONFIG_NET_DMA
1753 __skb_queue_purge(&sk->sk_async_wait_queue);
1754 #endif
1755
1756 inet->dport = 0;
1757
1758 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1759 inet_reset_saddr(sk);
1760
1761 sk->sk_shutdown = 0;
1762 sock_reset_flag(sk, SOCK_DONE);
1763 tp->srtt = 0;
1764 if ((tp->write_seq += tp->max_window + 2) == 0)
1765 tp->write_seq = 1;
1766 icsk->icsk_backoff = 0;
1767 tp->snd_cwnd = 2;
1768 icsk->icsk_probes_out = 0;
1769 tp->packets_out = 0;
1770 tp->snd_ssthresh = 0x7fffffff;
1771 tp->snd_cwnd_cnt = 0;
1772 tp->bytes_acked = 0;
1773 tcp_set_ca_state(sk, TCP_CA_Open);
1774 tcp_clear_retrans(tp);
1775 inet_csk_delack_init(sk);
1776 tcp_init_send_head(sk);
1777 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
1778 __sk_dst_reset(sk);
1779
1780 BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1781
1782 sk->sk_error_report(sk);
1783 return err;
1784 }
1785
1786 /*
1787 * Socket option code for TCP.
1788 */
1789 static int do_tcp_setsockopt(struct sock *sk, int level,
1790 int optname, char __user *optval, int optlen)
1791 {
1792 struct tcp_sock *tp = tcp_sk(sk);
1793 struct inet_connection_sock *icsk = inet_csk(sk);
1794 int val;
1795 int err = 0;
1796
1797 /* This is a string value all the others are int's */
1798 if (optname == TCP_CONGESTION) {
1799 char name[TCP_CA_NAME_MAX];
1800
1801 if (optlen < 1)
1802 return -EINVAL;
1803
1804 val = strncpy_from_user(name, optval,
1805 min(TCP_CA_NAME_MAX-1, optlen));
1806 if (val < 0)
1807 return -EFAULT;
1808 name[val] = 0;
1809
1810 lock_sock(sk);
1811 err = tcp_set_congestion_control(sk, name);
1812 release_sock(sk);
1813 return err;
1814 }
1815
1816 if (optlen < sizeof(int))
1817 return -EINVAL;
1818
1819 if (get_user(val, (int __user *)optval))
1820 return -EFAULT;
1821
1822 lock_sock(sk);
1823
1824 switch (optname) {
1825 case TCP_MAXSEG:
1826 /* Values greater than interface MTU won't take effect. However
1827 * at the point when this call is done we typically don't yet
1828 * know which interface is going to be used */
1829 if (val < 8 || val > MAX_TCP_WINDOW) {
1830 err = -EINVAL;
1831 break;
1832 }
1833 tp->rx_opt.user_mss = val;
1834 break;
1835
1836 case TCP_NODELAY:
1837 if (val) {
1838 /* TCP_NODELAY is weaker than TCP_CORK, so that
1839 * this option on corked socket is remembered, but
1840 * it is not activated until cork is cleared.
1841 *
1842 * However, when TCP_NODELAY is set we make
1843 * an explicit push, which overrides even TCP_CORK
1844 * for currently queued segments.
1845 */
1846 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
1847 tcp_push_pending_frames(sk);
1848 } else {
1849 tp->nonagle &= ~TCP_NAGLE_OFF;
1850 }
1851 break;
1852
1853 case TCP_CORK:
1854 /* When set indicates to always queue non-full frames.
1855 * Later the user clears this option and we transmit
1856 * any pending partial frames in the queue. This is
1857 * meant to be used alongside sendfile() to get properly
1858 * filled frames when the user (for example) must write
1859 * out headers with a write() call first and then use
1860 * sendfile to send out the data parts.
1861 *
1862 * TCP_CORK can be set together with TCP_NODELAY and it is
1863 * stronger than TCP_NODELAY.
1864 */
1865 if (val) {
1866 tp->nonagle |= TCP_NAGLE_CORK;
1867 } else {
1868 tp->nonagle &= ~TCP_NAGLE_CORK;
1869 if (tp->nonagle&TCP_NAGLE_OFF)
1870 tp->nonagle |= TCP_NAGLE_PUSH;
1871 tcp_push_pending_frames(sk);
1872 }
1873 break;
1874
1875 case TCP_KEEPIDLE:
1876 if (val < 1 || val > MAX_TCP_KEEPIDLE)
1877 err = -EINVAL;
1878 else {
1879 tp->keepalive_time = val * HZ;
1880 if (sock_flag(sk, SOCK_KEEPOPEN) &&
1881 !((1 << sk->sk_state) &
1882 (TCPF_CLOSE | TCPF_LISTEN))) {
1883 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
1884 if (tp->keepalive_time > elapsed)
1885 elapsed = tp->keepalive_time - elapsed;
1886 else
1887 elapsed = 0;
1888 inet_csk_reset_keepalive_timer(sk, elapsed);
1889 }
1890 }
1891 break;
1892 case TCP_KEEPINTVL:
1893 if (val < 1 || val > MAX_TCP_KEEPINTVL)
1894 err = -EINVAL;
1895 else
1896 tp->keepalive_intvl = val * HZ;
1897 break;
1898 case TCP_KEEPCNT:
1899 if (val < 1 || val > MAX_TCP_KEEPCNT)
1900 err = -EINVAL;
1901 else
1902 tp->keepalive_probes = val;
1903 break;
1904 case TCP_SYNCNT:
1905 if (val < 1 || val > MAX_TCP_SYNCNT)
1906 err = -EINVAL;
1907 else
1908 icsk->icsk_syn_retries = val;
1909 break;
1910
1911 case TCP_LINGER2:
1912 if (val < 0)
1913 tp->linger2 = -1;
1914 else if (val > sysctl_tcp_fin_timeout / HZ)
1915 tp->linger2 = 0;
1916 else
1917 tp->linger2 = val * HZ;
1918 break;
1919
1920 case TCP_DEFER_ACCEPT:
1921 icsk->icsk_accept_queue.rskq_defer_accept = 0;
1922 if (val > 0) {
1923 /* Translate value in seconds to number of
1924 * retransmits */
1925 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
1926 val > ((TCP_TIMEOUT_INIT / HZ) <<
1927 icsk->icsk_accept_queue.rskq_defer_accept))
1928 icsk->icsk_accept_queue.rskq_defer_accept++;
1929 icsk->icsk_accept_queue.rskq_defer_accept++;
1930 }
1931 break;
1932
1933 case TCP_WINDOW_CLAMP:
1934 if (!val) {
1935 if (sk->sk_state != TCP_CLOSE) {
1936 err = -EINVAL;
1937 break;
1938 }
1939 tp->window_clamp = 0;
1940 } else
1941 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
1942 SOCK_MIN_RCVBUF / 2 : val;
1943 break;
1944
1945 case TCP_QUICKACK:
1946 if (!val) {
1947 icsk->icsk_ack.pingpong = 1;
1948 } else {
1949 icsk->icsk_ack.pingpong = 0;
1950 if ((1 << sk->sk_state) &
1951 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
1952 inet_csk_ack_scheduled(sk)) {
1953 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
1954 tcp_cleanup_rbuf(sk, 1);
1955 if (!(val & 1))
1956 icsk->icsk_ack.pingpong = 1;
1957 }
1958 }
1959 break;
1960
1961 #ifdef CONFIG_TCP_MD5SIG
1962 case TCP_MD5SIG:
1963 /* Read the IP->Key mappings from userspace */
1964 err = tp->af_specific->md5_parse(sk, optval, optlen);
1965 break;
1966 #endif
1967
1968 default:
1969 err = -ENOPROTOOPT;
1970 break;
1971 }
1972
1973 release_sock(sk);
1974 return err;
1975 }
1976
1977 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
1978 int optlen)
1979 {
1980 struct inet_connection_sock *icsk = inet_csk(sk);
1981
1982 if (level != SOL_TCP)
1983 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1984 optval, optlen);
1985 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1986 }
1987
1988 #ifdef CONFIG_COMPAT
1989 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
1990 char __user *optval, int optlen)
1991 {
1992 if (level != SOL_TCP)
1993 return inet_csk_compat_setsockopt(sk, level, optname,
1994 optval, optlen);
1995 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1996 }
1997
1998 EXPORT_SYMBOL(compat_tcp_setsockopt);
1999 #endif
2000
2001 /* Return information about state of tcp endpoint in API format. */
2002 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2003 {
2004 struct tcp_sock *tp = tcp_sk(sk);
2005 const struct inet_connection_sock *icsk = inet_csk(sk);
2006 u32 now = tcp_time_stamp;
2007
2008 memset(info, 0, sizeof(*info));
2009
2010 info->tcpi_state = sk->sk_state;
2011 info->tcpi_ca_state = icsk->icsk_ca_state;
2012 info->tcpi_retransmits = icsk->icsk_retransmits;
2013 info->tcpi_probes = icsk->icsk_probes_out;
2014 info->tcpi_backoff = icsk->icsk_backoff;
2015
2016 if (tp->rx_opt.tstamp_ok)
2017 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2018 if (tcp_is_sack(tp))
2019 info->tcpi_options |= TCPI_OPT_SACK;
2020 if (tp->rx_opt.wscale_ok) {
2021 info->tcpi_options |= TCPI_OPT_WSCALE;
2022 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2023 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2024 }
2025
2026 if (tp->ecn_flags&TCP_ECN_OK)
2027 info->tcpi_options |= TCPI_OPT_ECN;
2028
2029 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2030 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2031 info->tcpi_snd_mss = tp->mss_cache;
2032 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2033
2034 if (sk->sk_state == TCP_LISTEN) {
2035 info->tcpi_unacked = sk->sk_ack_backlog;
2036 info->tcpi_sacked = sk->sk_max_ack_backlog;
2037 } else {
2038 info->tcpi_unacked = tp->packets_out;
2039 info->tcpi_sacked = tp->sacked_out;
2040 }
2041 info->tcpi_lost = tp->lost_out;
2042 info->tcpi_retrans = tp->retrans_out;
2043 info->tcpi_fackets = tp->fackets_out;
2044
2045 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2046 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2047 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2048
2049 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2050 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2051 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2052 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2053 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2054 info->tcpi_snd_cwnd = tp->snd_cwnd;
2055 info->tcpi_advmss = tp->advmss;
2056 info->tcpi_reordering = tp->reordering;
2057
2058 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2059 info->tcpi_rcv_space = tp->rcvq_space.space;
2060
2061 info->tcpi_total_retrans = tp->total_retrans;
2062 }
2063
2064 EXPORT_SYMBOL_GPL(tcp_get_info);
2065
2066 static int do_tcp_getsockopt(struct sock *sk, int level,
2067 int optname, char __user *optval, int __user *optlen)
2068 {
2069 struct inet_connection_sock *icsk = inet_csk(sk);
2070 struct tcp_sock *tp = tcp_sk(sk);
2071 int val, len;
2072
2073 if (get_user(len, optlen))
2074 return -EFAULT;
2075
2076 len = min_t(unsigned int, len, sizeof(int));
2077
2078 if (len < 0)
2079 return -EINVAL;
2080
2081 switch (optname) {
2082 case TCP_MAXSEG:
2083 val = tp->mss_cache;
2084 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2085 val = tp->rx_opt.user_mss;
2086 break;
2087 case TCP_NODELAY:
2088 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2089 break;
2090 case TCP_CORK:
2091 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2092 break;
2093 case TCP_KEEPIDLE:
2094 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2095 break;
2096 case TCP_KEEPINTVL:
2097 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2098 break;
2099 case TCP_KEEPCNT:
2100 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2101 break;
2102 case TCP_SYNCNT:
2103 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2104 break;
2105 case TCP_LINGER2:
2106 val = tp->linger2;
2107 if (val >= 0)
2108 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2109 break;
2110 case TCP_DEFER_ACCEPT:
2111 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2112 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2113 break;
2114 case TCP_WINDOW_CLAMP:
2115 val = tp->window_clamp;
2116 break;
2117 case TCP_INFO: {
2118 struct tcp_info info;
2119
2120 if (get_user(len, optlen))
2121 return -EFAULT;
2122
2123 tcp_get_info(sk, &info);
2124
2125 len = min_t(unsigned int, len, sizeof(info));
2126 if (put_user(len, optlen))
2127 return -EFAULT;
2128 if (copy_to_user(optval, &info, len))
2129 return -EFAULT;
2130 return 0;
2131 }
2132 case TCP_QUICKACK:
2133 val = !icsk->icsk_ack.pingpong;
2134 break;
2135
2136 case TCP_CONGESTION:
2137 if (get_user(len, optlen))
2138 return -EFAULT;
2139 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2140 if (put_user(len, optlen))
2141 return -EFAULT;
2142 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2143 return -EFAULT;
2144 return 0;
2145 default:
2146 return -ENOPROTOOPT;
2147 }
2148
2149 if (put_user(len, optlen))
2150 return -EFAULT;
2151 if (copy_to_user(optval, &val, len))
2152 return -EFAULT;
2153 return 0;
2154 }
2155
2156 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2157 int __user *optlen)
2158 {
2159 struct inet_connection_sock *icsk = inet_csk(sk);
2160
2161 if (level != SOL_TCP)
2162 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2163 optval, optlen);
2164 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2165 }
2166
2167 #ifdef CONFIG_COMPAT
2168 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2169 char __user *optval, int __user *optlen)
2170 {
2171 if (level != SOL_TCP)
2172 return inet_csk_compat_getsockopt(sk, level, optname,
2173 optval, optlen);
2174 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2175 }
2176
2177 EXPORT_SYMBOL(compat_tcp_getsockopt);
2178 #endif
2179
2180 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2181 {
2182 struct sk_buff *segs = ERR_PTR(-EINVAL);
2183 struct tcphdr *th;
2184 unsigned thlen;
2185 unsigned int seq;
2186 __be32 delta;
2187 unsigned int oldlen;
2188 unsigned int len;
2189
2190 if (!pskb_may_pull(skb, sizeof(*th)))
2191 goto out;
2192
2193 th = tcp_hdr(skb);
2194 thlen = th->doff * 4;
2195 if (thlen < sizeof(*th))
2196 goto out;
2197
2198 if (!pskb_may_pull(skb, thlen))
2199 goto out;
2200
2201 oldlen = (u16)~skb->len;
2202 __skb_pull(skb, thlen);
2203
2204 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2205 /* Packet is from an untrusted source, reset gso_segs. */
2206 int type = skb_shinfo(skb)->gso_type;
2207 int mss;
2208
2209 if (unlikely(type &
2210 ~(SKB_GSO_TCPV4 |
2211 SKB_GSO_DODGY |
2212 SKB_GSO_TCP_ECN |
2213 SKB_GSO_TCPV6 |
2214 0) ||
2215 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2216 goto out;
2217
2218 mss = skb_shinfo(skb)->gso_size;
2219 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2220
2221 segs = NULL;
2222 goto out;
2223 }
2224
2225 segs = skb_segment(skb, features);
2226 if (IS_ERR(segs))
2227 goto out;
2228
2229 len = skb_shinfo(skb)->gso_size;
2230 delta = htonl(oldlen + (thlen + len));
2231
2232 skb = segs;
2233 th = tcp_hdr(skb);
2234 seq = ntohl(th->seq);
2235
2236 do {
2237 th->fin = th->psh = 0;
2238
2239 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2240 (__force u32)delta));
2241 if (skb->ip_summed != CHECKSUM_PARTIAL)
2242 th->check =
2243 csum_fold(csum_partial(skb_transport_header(skb),
2244 thlen, skb->csum));
2245
2246 seq += len;
2247 skb = skb->next;
2248 th = tcp_hdr(skb);
2249
2250 th->seq = htonl(seq);
2251 th->cwr = 0;
2252 } while (skb->next);
2253
2254 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2255 skb->data_len);
2256 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2257 (__force u32)delta));
2258 if (skb->ip_summed != CHECKSUM_PARTIAL)
2259 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2260 thlen, skb->csum));
2261
2262 out:
2263 return segs;
2264 }
2265 EXPORT_SYMBOL(tcp_tso_segment);
2266
2267 #ifdef CONFIG_TCP_MD5SIG
2268 static unsigned long tcp_md5sig_users;
2269 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2270 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2271
2272 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2273 {
2274 int cpu;
2275 for_each_possible_cpu(cpu) {
2276 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2277 if (p) {
2278 if (p->md5_desc.tfm)
2279 crypto_free_hash(p->md5_desc.tfm);
2280 kfree(p);
2281 p = NULL;
2282 }
2283 }
2284 free_percpu(pool);
2285 }
2286
2287 void tcp_free_md5sig_pool(void)
2288 {
2289 struct tcp_md5sig_pool **pool = NULL;
2290
2291 spin_lock_bh(&tcp_md5sig_pool_lock);
2292 if (--tcp_md5sig_users == 0) {
2293 pool = tcp_md5sig_pool;
2294 tcp_md5sig_pool = NULL;
2295 }
2296 spin_unlock_bh(&tcp_md5sig_pool_lock);
2297 if (pool)
2298 __tcp_free_md5sig_pool(pool);
2299 }
2300
2301 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2302
2303 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
2304 {
2305 int cpu;
2306 struct tcp_md5sig_pool **pool;
2307
2308 pool = alloc_percpu(struct tcp_md5sig_pool *);
2309 if (!pool)
2310 return NULL;
2311
2312 for_each_possible_cpu(cpu) {
2313 struct tcp_md5sig_pool *p;
2314 struct crypto_hash *hash;
2315
2316 p = kzalloc(sizeof(*p), GFP_KERNEL);
2317 if (!p)
2318 goto out_free;
2319 *per_cpu_ptr(pool, cpu) = p;
2320
2321 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2322 if (!hash || IS_ERR(hash))
2323 goto out_free;
2324
2325 p->md5_desc.tfm = hash;
2326 }
2327 return pool;
2328 out_free:
2329 __tcp_free_md5sig_pool(pool);
2330 return NULL;
2331 }
2332
2333 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
2334 {
2335 struct tcp_md5sig_pool **pool;
2336 int alloc = 0;
2337
2338 retry:
2339 spin_lock_bh(&tcp_md5sig_pool_lock);
2340 pool = tcp_md5sig_pool;
2341 if (tcp_md5sig_users++ == 0) {
2342 alloc = 1;
2343 spin_unlock_bh(&tcp_md5sig_pool_lock);
2344 } else if (!pool) {
2345 tcp_md5sig_users--;
2346 spin_unlock_bh(&tcp_md5sig_pool_lock);
2347 cpu_relax();
2348 goto retry;
2349 } else
2350 spin_unlock_bh(&tcp_md5sig_pool_lock);
2351
2352 if (alloc) {
2353 /* we cannot hold spinlock here because this may sleep. */
2354 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
2355 spin_lock_bh(&tcp_md5sig_pool_lock);
2356 if (!p) {
2357 tcp_md5sig_users--;
2358 spin_unlock_bh(&tcp_md5sig_pool_lock);
2359 return NULL;
2360 }
2361 pool = tcp_md5sig_pool;
2362 if (pool) {
2363 /* oops, it has already been assigned. */
2364 spin_unlock_bh(&tcp_md5sig_pool_lock);
2365 __tcp_free_md5sig_pool(p);
2366 } else {
2367 tcp_md5sig_pool = pool = p;
2368 spin_unlock_bh(&tcp_md5sig_pool_lock);
2369 }
2370 }
2371 return pool;
2372 }
2373
2374 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2375
2376 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2377 {
2378 struct tcp_md5sig_pool **p;
2379 spin_lock_bh(&tcp_md5sig_pool_lock);
2380 p = tcp_md5sig_pool;
2381 if (p)
2382 tcp_md5sig_users++;
2383 spin_unlock_bh(&tcp_md5sig_pool_lock);
2384 return (p ? *per_cpu_ptr(p, cpu) : NULL);
2385 }
2386
2387 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2388
2389 void __tcp_put_md5sig_pool(void)
2390 {
2391 tcp_free_md5sig_pool();
2392 }
2393
2394 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2395 #endif
2396
2397 void tcp_done(struct sock *sk)
2398 {
2399 if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2400 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
2401
2402 tcp_set_state(sk, TCP_CLOSE);
2403 tcp_clear_xmit_timers(sk);
2404
2405 sk->sk_shutdown = SHUTDOWN_MASK;
2406
2407 if (!sock_flag(sk, SOCK_DEAD))
2408 sk->sk_state_change(sk);
2409 else
2410 inet_csk_destroy_sock(sk);
2411 }
2412 EXPORT_SYMBOL_GPL(tcp_done);
2413
2414 extern void __skb_cb_too_small_for_tcp(int, int);
2415 extern struct tcp_congestion_ops tcp_reno;
2416
2417 static __initdata unsigned long thash_entries;
2418 static int __init set_thash_entries(char *str)
2419 {
2420 if (!str)
2421 return 0;
2422 thash_entries = simple_strtoul(str, &str, 0);
2423 return 1;
2424 }
2425 __setup("thash_entries=", set_thash_entries);
2426
2427 void __init tcp_init(void)
2428 {
2429 struct sk_buff *skb = NULL;
2430 unsigned long limit;
2431 int order, i, max_share;
2432
2433 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2434 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2435 sizeof(skb->cb));
2436
2437 tcp_hashinfo.bind_bucket_cachep =
2438 kmem_cache_create("tcp_bind_bucket",
2439 sizeof(struct inet_bind_bucket), 0,
2440 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2441
2442 /* Size and allocate the main established and bind bucket
2443 * hash tables.
2444 *
2445 * The methodology is similar to that of the buffer cache.
2446 */
2447 tcp_hashinfo.ehash =
2448 alloc_large_system_hash("TCP established",
2449 sizeof(struct inet_ehash_bucket),
2450 thash_entries,
2451 (num_physpages >= 128 * 1024) ?
2452 13 : 15,
2453 0,
2454 &tcp_hashinfo.ehash_size,
2455 NULL,
2456 0);
2457 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2458 for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2459 rwlock_init(&tcp_hashinfo.ehash[i].lock);
2460 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2461 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain);
2462 }
2463
2464 tcp_hashinfo.bhash =
2465 alloc_large_system_hash("TCP bind",
2466 sizeof(struct inet_bind_hashbucket),
2467 tcp_hashinfo.ehash_size,
2468 (num_physpages >= 128 * 1024) ?
2469 13 : 15,
2470 0,
2471 &tcp_hashinfo.bhash_size,
2472 NULL,
2473 64 * 1024);
2474 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2475 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2476 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2477 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2478 }
2479
2480 /* Try to be a bit smarter and adjust defaults depending
2481 * on available memory.
2482 */
2483 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2484 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2485 order++)
2486 ;
2487 if (order >= 4) {
2488 tcp_death_row.sysctl_max_tw_buckets = 180000;
2489 sysctl_tcp_max_orphans = 4096 << (order - 4);
2490 sysctl_max_syn_backlog = 1024;
2491 } else if (order < 3) {
2492 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2493 sysctl_tcp_max_orphans >>= (3 - order);
2494 sysctl_max_syn_backlog = 128;
2495 }
2496
2497 /* Set the pressure threshold to be a fraction of global memory that
2498 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2499 * memory, with a floor of 128 pages.
2500 */
2501 limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
2502 limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
2503 limit = max(limit, 128UL);
2504 sysctl_tcp_mem[0] = limit / 4 * 3;
2505 sysctl_tcp_mem[1] = limit;
2506 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
2507
2508 /* Set per-socket limits to no more than 1/128 the pressure threshold */
2509 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2510 max_share = min(4UL*1024*1024, limit);
2511
2512 sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM;
2513 sysctl_tcp_wmem[1] = 16*1024;
2514 sysctl_tcp_wmem[2] = max(64*1024, max_share);
2515
2516 sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM;
2517 sysctl_tcp_rmem[1] = 87380;
2518 sysctl_tcp_rmem[2] = max(87380, max_share);
2519
2520 printk(KERN_INFO "TCP: Hash tables configured "
2521 "(established %d bind %d)\n",
2522 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
2523
2524 tcp_register_congestion_control(&tcp_reno);
2525 }
2526
2527 EXPORT_SYMBOL(tcp_close);
2528 EXPORT_SYMBOL(tcp_disconnect);
2529 EXPORT_SYMBOL(tcp_getsockopt);
2530 EXPORT_SYMBOL(tcp_ioctl);
2531 EXPORT_SYMBOL(tcp_poll);
2532 EXPORT_SYMBOL(tcp_read_sock);
2533 EXPORT_SYMBOL(tcp_recvmsg);
2534 EXPORT_SYMBOL(tcp_sendmsg);
2535 EXPORT_SYMBOL(tcp_sendpage);
2536 EXPORT_SYMBOL(tcp_setsockopt);
2537 EXPORT_SYMBOL(tcp_shutdown);
2538 EXPORT_SYMBOL(tcp_statistics);
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