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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt...
[linux-2.6/mini2440.git] / net / ipv4 / tcp.c
blob91145244ea630777e7e4a2e7f112f3c31bc7f90e
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 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Mark Evans, <evansmp@uhura.aston.ac.uk>
11 * Corey Minyard <wf-rch!minyard@relay.EU.net>
12 * Florian La Roche, <flla@stud.uni-sb.de>
13 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
14 * Linus Torvalds, <torvalds@cs.helsinki.fi>
15 * Alan Cox, <gw4pts@gw4pts.ampr.org>
16 * Matthew Dillon, <dillon@apollo.west.oic.com>
17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
18 * Jorge Cwik, <jorge@laser.satlink.net>
19 *
20 * Fixes:
21 * Alan Cox : Numerous verify_area() calls
22 * Alan Cox : Set the ACK bit on a reset
23 * Alan Cox : Stopped it crashing if it closed while
24 * sk->inuse=1 and was trying to connect
25 * (tcp_err()).
26 * Alan Cox : All icmp error handling was broken
27 * pointers passed where wrong and the
28 * socket was looked up backwards. Nobody
29 * tested any icmp error code obviously.
30 * Alan Cox : tcp_err() now handled properly. It
31 * wakes people on errors. poll
32 * behaves and the icmp error race
33 * has gone by moving it into sock.c
34 * Alan Cox : tcp_send_reset() fixed to work for
35 * everything not just packets for
36 * unknown sockets.
37 * Alan Cox : tcp option processing.
38 * Alan Cox : Reset tweaked (still not 100%) [Had
39 * syn rule wrong]
40 * Herp Rosmanith : More reset fixes
41 * Alan Cox : No longer acks invalid rst frames.
42 * Acking any kind of RST is right out.
43 * Alan Cox : Sets an ignore me flag on an rst
44 * receive otherwise odd bits of prattle
45 * escape still
46 * Alan Cox : Fixed another acking RST frame bug.
47 * Should stop LAN workplace lockups.
48 * Alan Cox : Some tidyups using the new skb list
49 * facilities
50 * Alan Cox : sk->keepopen now seems to work
51 * Alan Cox : Pulls options out correctly on accepts
52 * Alan Cox : Fixed assorted sk->rqueue->next errors
53 * Alan Cox : PSH doesn't end a TCP read. Switched a
54 * bit to skb ops.
55 * Alan Cox : Tidied tcp_data to avoid a potential
56 * nasty.
57 * Alan Cox : Added some better commenting, as the
58 * tcp is hard to follow
59 * Alan Cox : Removed incorrect check for 20 * psh
60 * Michael O'Reilly : ack < copied bug fix.
61 * Johannes Stille : Misc tcp fixes (not all in yet).
62 * Alan Cox : FIN with no memory -> CRASH
63 * Alan Cox : Added socket option proto entries.
64 * Also added awareness of them to accept.
65 * Alan Cox : Added TCP options (SOL_TCP)
66 * Alan Cox : Switched wakeup calls to callbacks,
67 * so the kernel can layer network
68 * sockets.
69 * Alan Cox : Use ip_tos/ip_ttl settings.
70 * Alan Cox : Handle FIN (more) properly (we hope).
71 * Alan Cox : RST frames sent on unsynchronised
72 * state ack error.
73 * Alan Cox : Put in missing check for SYN bit.
74 * Alan Cox : Added tcp_select_window() aka NET2E
75 * window non shrink trick.
76 * Alan Cox : Added a couple of small NET2E timer
77 * fixes
78 * Charles Hedrick : TCP fixes
79 * Toomas Tamm : TCP window fixes
80 * Alan Cox : Small URG fix to rlogin ^C ack fight
81 * Charles Hedrick : Rewrote most of it to actually work
82 * Linus : Rewrote tcp_read() and URG handling
83 * completely
84 * Gerhard Koerting: Fixed some missing timer handling
85 * Matthew Dillon : Reworked TCP machine states as per RFC
86 * Gerhard Koerting: PC/TCP workarounds
87 * Adam Caldwell : Assorted timer/timing errors
88 * Matthew Dillon : Fixed another RST bug
89 * Alan Cox : Move to kernel side addressing changes.
90 * Alan Cox : Beginning work on TCP fastpathing
91 * (not yet usable)
92 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
93 * Alan Cox : TCP fast path debugging
94 * Alan Cox : Window clamping
95 * Michael Riepe : Bug in tcp_check()
96 * Matt Dillon : More TCP improvements and RST bug fixes
97 * Matt Dillon : Yet more small nasties remove from the
98 * TCP code (Be very nice to this man if
99 * tcp finally works 100%) 8)
100 * Alan Cox : BSD accept semantics.
101 * Alan Cox : Reset on closedown bug.
102 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
103 * Michael Pall : Handle poll() after URG properly in
104 * all cases.
105 * Michael Pall : Undo the last fix in tcp_read_urg()
106 * (multi URG PUSH broke rlogin).
107 * Michael Pall : Fix the multi URG PUSH problem in
108 * tcp_readable(), poll() after URG
109 * works now.
110 * Michael Pall : recv(...,MSG_OOB) never blocks in the
111 * BSD api.
112 * Alan Cox : Changed the semantics of sk->socket to
113 * fix a race and a signal problem with
114 * accept() and async I/O.
115 * Alan Cox : Relaxed the rules on tcp_sendto().
116 * Yury Shevchuk : Really fixed accept() blocking problem.
117 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
118 * clients/servers which listen in on
119 * fixed ports.
120 * Alan Cox : Cleaned the above up and shrank it to
121 * a sensible code size.
122 * Alan Cox : Self connect lockup fix.
123 * Alan Cox : No connect to multicast.
124 * Ross Biro : Close unaccepted children on master
125 * socket close.
126 * Alan Cox : Reset tracing code.
127 * Alan Cox : Spurious resets on shutdown.
128 * Alan Cox : Giant 15 minute/60 second timer error
129 * Alan Cox : Small whoops in polling before an
130 * accept.
131 * Alan Cox : Kept the state trace facility since
132 * it's handy for debugging.
133 * Alan Cox : More reset handler fixes.
134 * Alan Cox : Started rewriting the code based on
135 * the RFC's for other useful protocol
136 * references see: Comer, KA9Q NOS, and
137 * for a reference on the difference
138 * between specifications and how BSD
139 * works see the 4.4lite source.
140 * A.N.Kuznetsov : Don't time wait on completion of tidy
141 * close.
142 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
143 * Linus Torvalds : Fixed BSD port reuse to work first syn
144 * Alan Cox : Reimplemented timers as per the RFC
145 * and using multiple timers for sanity.
146 * Alan Cox : Small bug fixes, and a lot of new
147 * comments.
148 * Alan Cox : Fixed dual reader crash by locking
149 * the buffers (much like datagram.c)
150 * Alan Cox : Fixed stuck sockets in probe. A probe
151 * now gets fed up of retrying without
152 * (even a no space) answer.
153 * Alan Cox : Extracted closing code better
154 * Alan Cox : Fixed the closing state machine to
155 * resemble the RFC.
156 * Alan Cox : More 'per spec' fixes.
157 * Jorge Cwik : Even faster checksumming.
158 * Alan Cox : tcp_data() doesn't ack illegal PSH
159 * only frames. At least one pc tcp stack
160 * generates them.
161 * Alan Cox : Cache last socket.
162 * Alan Cox : Per route irtt.
163 * Matt Day : poll()->select() match BSD precisely on error
164 * Alan Cox : New buffers
165 * Marc Tamsky : Various sk->prot->retransmits and
166 * sk->retransmits misupdating fixed.
167 * Fixed tcp_write_timeout: stuck close,
168 * and TCP syn retries gets used now.
169 * Mark Yarvis : In tcp_read_wakeup(), don't send an
170 * ack if state is TCP_CLOSED.
171 * Alan Cox : Look up device on a retransmit - routes may
172 * change. Doesn't yet cope with MSS shrink right
173 * but it's a start!
174 * Marc Tamsky : Closing in closing fixes.
175 * Mike Shaver : RFC1122 verifications.
176 * Alan Cox : rcv_saddr errors.
177 * Alan Cox : Block double connect().
178 * Alan Cox : Small hooks for enSKIP.
179 * Alexey Kuznetsov: Path MTU discovery.
180 * Alan Cox : Support soft errors.
181 * Alan Cox : Fix MTU discovery pathological case
182 * when the remote claims no mtu!
183 * Marc Tamsky : TCP_CLOSE fix.
184 * Colin (G3TNE) : Send a reset on syn ack replies in
185 * window but wrong (fixes NT lpd problems)
186 * Pedro Roque : Better TCP window handling, delayed ack.
187 * Joerg Reuter : No modification of locked buffers in
188 * tcp_do_retransmit()
189 * Eric Schenk : Changed receiver side silly window
190 * avoidance algorithm to BSD style
191 * algorithm. This doubles throughput
192 * against machines running Solaris,
193 * and seems to result in general
194 * improvement.
195 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
196 * Willy Konynenberg : Transparent proxying support.
197 * Mike McLagan : Routing by source
198 * Keith Owens : Do proper merging with partial SKB's in
199 * tcp_do_sendmsg to avoid burstiness.
200 * Eric Schenk : Fix fast close down bug with
201 * shutdown() followed by close().
202 * Andi Kleen : Make poll agree with SIGIO
203 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
204 * lingertime == 0 (RFC 793 ABORT Call)
205 * Hirokazu Takahashi : Use copy_from_user() instead of
206 * csum_and_copy_from_user() if possible.
207 *
208 * This program is free software; you can redistribute it and/or
209 * modify it under the terms of the GNU General Public License
210 * as published by the Free Software Foundation; either version
211 * 2 of the License, or(at your option) any later version.
212 *
213 * Description of States:
214 *
215 * TCP_SYN_SENT sent a connection request, waiting for ack
216 *
217 * TCP_SYN_RECV received a connection request, sent ack,
218 * waiting for final ack in three-way handshake.
219 *
220 * TCP_ESTABLISHED connection established
221 *
222 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
223 * transmission of remaining buffered data
224 *
225 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
226 * to shutdown
227 *
228 * TCP_CLOSING both sides have shutdown but we still have
229 * data we have to finish sending
230 *
231 * TCP_TIME_WAIT timeout to catch resent junk before entering
232 * closed, can only be entered from FIN_WAIT2
233 * or CLOSING. Required because the other end
234 * may not have gotten our last ACK causing it
235 * to retransmit the data packet (which we ignore)
236 *
237 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
238 * us to finish writing our data and to shutdown
239 * (we have to close() to move on to LAST_ACK)
240 *
241 * TCP_LAST_ACK out side has shutdown after remote has
242 * shutdown. There may still be data in our
243 * buffer that we have to finish sending
244 *
245 * TCP_CLOSE socket is finished
246 */
247
248 #include <linux/kernel.h>
249 #include <linux/module.h>
250 #include <linux/types.h>
251 #include <linux/fcntl.h>
252 #include <linux/poll.h>
253 #include <linux/init.h>
254 #include <linux/fs.h>
255 #include <linux/skbuff.h>
256 #include <linux/scatterlist.h>
257 #include <linux/splice.h>
258 #include <linux/net.h>
259 #include <linux/socket.h>
260 #include <linux/random.h>
261 #include <linux/bootmem.h>
262 #include <linux/highmem.h>
263 #include <linux/swap.h>
264 #include <linux/cache.h>
265 #include <linux/err.h>
266 #include <linux/crypto.h>
267
268 #include <net/icmp.h>
269 #include <net/tcp.h>
270 #include <net/xfrm.h>
271 #include <net/ip.h>
272 #include <net/netdma.h>
273 #include <net/sock.h>
274
275 #include <asm/uaccess.h>
276 #include <asm/ioctls.h>
277
278 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
279
280 struct percpu_counter tcp_orphan_count;
281 EXPORT_SYMBOL_GPL(tcp_orphan_count);
282
283 int sysctl_tcp_mem[3] __read_mostly;
284 int sysctl_tcp_wmem[3] __read_mostly;
285 int sysctl_tcp_rmem[3] __read_mostly;
286
287 EXPORT_SYMBOL(sysctl_tcp_mem);
288 EXPORT_SYMBOL(sysctl_tcp_rmem);
289 EXPORT_SYMBOL(sysctl_tcp_wmem);
290
291 atomic_t tcp_memory_allocated; /* Current allocated memory. */
292 EXPORT_SYMBOL(tcp_memory_allocated);
293
294 /*
295 * Current number of TCP sockets.
296 */
297 struct percpu_counter tcp_sockets_allocated;
298 EXPORT_SYMBOL(tcp_sockets_allocated);
299
300 /*
301 * TCP splice context
302 */
303 struct tcp_splice_state {
304 struct pipe_inode_info *pipe;
305 size_t len;
306 unsigned int flags;
307 };
308
309 /*
310 * Pressure flag: try to collapse.
311 * Technical note: it is used by multiple contexts non atomically.
312 * All the __sk_mem_schedule() is of this nature: accounting
313 * is strict, actions are advisory and have some latency.
314 */
315 int tcp_memory_pressure __read_mostly;
316
317 EXPORT_SYMBOL(tcp_memory_pressure);
318
319 void tcp_enter_memory_pressure(struct sock *sk)
320 {
321 if (!tcp_memory_pressure) {
322 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
323 tcp_memory_pressure = 1;
324 }
325 }
326
327 EXPORT_SYMBOL(tcp_enter_memory_pressure);
328
329 /*
330 * Wait for a TCP event.
331 *
332 * Note that we don't need to lock the socket, as the upper poll layers
333 * take care of normal races (between the test and the event) and we don't
334 * go look at any of the socket buffers directly.
335 */
336 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
337 {
338 unsigned int mask;
339 struct sock *sk = sock->sk;
340 struct tcp_sock *tp = tcp_sk(sk);
341
342 sock_poll_wait(file, sk->sk_sleep, wait);
343 if (sk->sk_state == TCP_LISTEN)
344 return inet_csk_listen_poll(sk);
345
346 /* Socket is not locked. We are protected from async events
347 * by poll logic and correct handling of state changes
348 * made by other threads is impossible in any case.
349 */
350
351 mask = 0;
352 if (sk->sk_err)
353 mask = POLLERR;
354
355 /*
356 * POLLHUP is certainly not done right. But poll() doesn't
357 * have a notion of HUP in just one direction, and for a
358 * socket the read side is more interesting.
359 *
360 * Some poll() documentation says that POLLHUP is incompatible
361 * with the POLLOUT/POLLWR flags, so somebody should check this
362 * all. But careful, it tends to be safer to return too many
363 * bits than too few, and you can easily break real applications
364 * if you don't tell them that something has hung up!
365 *
366 * Check-me.
367 *
368 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
369 * our fs/select.c). It means that after we received EOF,
370 * poll always returns immediately, making impossible poll() on write()
371 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
372 * if and only if shutdown has been made in both directions.
373 * Actually, it is interesting to look how Solaris and DUX
374 * solve this dilemma. I would prefer, if POLLHUP were maskable,
375 * then we could set it on SND_SHUTDOWN. BTW examples given
376 * in Stevens' books assume exactly this behaviour, it explains
377 * why POLLHUP is incompatible with POLLOUT. --ANK
378 *
379 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
380 * blocking on fresh not-connected or disconnected socket. --ANK
381 */
382 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
383 mask |= POLLHUP;
384 if (sk->sk_shutdown & RCV_SHUTDOWN)
385 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
386
387 /* Connected? */
388 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
389 int target = sock_rcvlowat(sk, 0, INT_MAX);
390
391 if (tp->urg_seq == tp->copied_seq &&
392 !sock_flag(sk, SOCK_URGINLINE) &&
393 tp->urg_data)
394 target--;
395
396 /* Potential race condition. If read of tp below will
397 * escape above sk->sk_state, we can be illegally awaken
398 * in SYN_* states. */
399 if (tp->rcv_nxt - tp->copied_seq >= target)
400 mask |= POLLIN | POLLRDNORM;
401
402 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
403 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
404 mask |= POLLOUT | POLLWRNORM;
405 } else { /* send SIGIO later */
406 set_bit(SOCK_ASYNC_NOSPACE,
407 &sk->sk_socket->flags);
408 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
409
410 /* Race breaker. If space is freed after
411 * wspace test but before the flags are set,
412 * IO signal will be lost.
413 */
414 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
415 mask |= POLLOUT | POLLWRNORM;
416 }
417 }
418
419 if (tp->urg_data & TCP_URG_VALID)
420 mask |= POLLPRI;
421 }
422 return mask;
423 }
424
425 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
426 {
427 struct tcp_sock *tp = tcp_sk(sk);
428 int answ;
429
430 switch (cmd) {
431 case SIOCINQ:
432 if (sk->sk_state == TCP_LISTEN)
433 return -EINVAL;
434
435 lock_sock(sk);
436 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
437 answ = 0;
438 else if (sock_flag(sk, SOCK_URGINLINE) ||
439 !tp->urg_data ||
440 before(tp->urg_seq, tp->copied_seq) ||
441 !before(tp->urg_seq, tp->rcv_nxt)) {
442 struct sk_buff *skb;
443
444 answ = tp->rcv_nxt - tp->copied_seq;
445
446 /* Subtract 1, if FIN is in queue. */
447 skb = skb_peek_tail(&sk->sk_receive_queue);
448 if (answ && skb)
449 answ -= tcp_hdr(skb)->fin;
450 } else
451 answ = tp->urg_seq - tp->copied_seq;
452 release_sock(sk);
453 break;
454 case SIOCATMARK:
455 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
456 break;
457 case SIOCOUTQ:
458 if (sk->sk_state == TCP_LISTEN)
459 return -EINVAL;
460
461 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
462 answ = 0;
463 else
464 answ = tp->write_seq - tp->snd_una;
465 break;
466 default:
467 return -ENOIOCTLCMD;
468 }
469
470 return put_user(answ, (int __user *)arg);
471 }
472
473 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
474 {
475 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
476 tp->pushed_seq = tp->write_seq;
477 }
478
479 static inline int forced_push(struct tcp_sock *tp)
480 {
481 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
482 }
483
484 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
485 {
486 struct tcp_sock *tp = tcp_sk(sk);
487 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
488
489 skb->csum = 0;
490 tcb->seq = tcb->end_seq = tp->write_seq;
491 tcb->flags = TCPCB_FLAG_ACK;
492 tcb->sacked = 0;
493 skb_header_release(skb);
494 tcp_add_write_queue_tail(sk, skb);
495 sk->sk_wmem_queued += skb->truesize;
496 sk_mem_charge(sk, skb->truesize);
497 if (tp->nonagle & TCP_NAGLE_PUSH)
498 tp->nonagle &= ~TCP_NAGLE_PUSH;
499 }
500
501 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
502 struct sk_buff *skb)
503 {
504 if (flags & MSG_OOB)
505 tp->snd_up = tp->write_seq;
506 }
507
508 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
509 int nonagle)
510 {
511 struct tcp_sock *tp = tcp_sk(sk);
512
513 if (tcp_send_head(sk)) {
514 struct sk_buff *skb = tcp_write_queue_tail(sk);
515 if (!(flags & MSG_MORE) || forced_push(tp))
516 tcp_mark_push(tp, skb);
517 tcp_mark_urg(tp, flags, skb);
518 __tcp_push_pending_frames(sk, mss_now,
519 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
520 }
521 }
522
523 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
524 unsigned int offset, size_t len)
525 {
526 struct tcp_splice_state *tss = rd_desc->arg.data;
527 int ret;
528
529 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
530 tss->flags);
531 if (ret > 0)
532 rd_desc->count -= ret;
533 return ret;
534 }
535
536 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
537 {
538 /* Store TCP splice context information in read_descriptor_t. */
539 read_descriptor_t rd_desc = {
540 .arg.data = tss,
541 .count = tss->len,
542 };
543
544 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
545 }
546
547 /**
548 * tcp_splice_read - splice data from TCP socket to a pipe
549 * @sock: socket to splice from
550 * @ppos: position (not valid)
551 * @pipe: pipe to splice to
552 * @len: number of bytes to splice
553 * @flags: splice modifier flags
554 *
555 * Description:
556 * Will read pages from given socket and fill them into a pipe.
557 *
558 **/
559 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
560 struct pipe_inode_info *pipe, size_t len,
561 unsigned int flags)
562 {
563 struct sock *sk = sock->sk;
564 struct tcp_splice_state tss = {
565 .pipe = pipe,
566 .len = len,
567 .flags = flags,
568 };
569 long timeo;
570 ssize_t spliced;
571 int ret;
572
573 /*
574 * We can't seek on a socket input
575 */
576 if (unlikely(*ppos))
577 return -ESPIPE;
578
579 ret = spliced = 0;
580
581 lock_sock(sk);
582
583 timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK);
584 while (tss.len) {
585 ret = __tcp_splice_read(sk, &tss);
586 if (ret < 0)
587 break;
588 else if (!ret) {
589 if (spliced)
590 break;
591 if (sock_flag(sk, SOCK_DONE))
592 break;
593 if (sk->sk_err) {
594 ret = sock_error(sk);
595 break;
596 }
597 if (sk->sk_shutdown & RCV_SHUTDOWN)
598 break;
599 if (sk->sk_state == TCP_CLOSE) {
600 /*
601 * This occurs when user tries to read
602 * from never connected socket.
603 */
604 if (!sock_flag(sk, SOCK_DONE))
605 ret = -ENOTCONN;
606 break;
607 }
608 if (!timeo) {
609 ret = -EAGAIN;
610 break;
611 }
612 sk_wait_data(sk, &timeo);
613 if (signal_pending(current)) {
614 ret = sock_intr_errno(timeo);
615 break;
616 }
617 continue;
618 }
619 tss.len -= ret;
620 spliced += ret;
621
622 if (!timeo)
623 break;
624 release_sock(sk);
625 lock_sock(sk);
626
627 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
628 (sk->sk_shutdown & RCV_SHUTDOWN) ||
629 signal_pending(current))
630 break;
631 }
632
633 release_sock(sk);
634
635 if (spliced)
636 return spliced;
637
638 return ret;
639 }
640
641 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
642 {
643 struct sk_buff *skb;
644
645 /* The TCP header must be at least 32-bit aligned. */
646 size = ALIGN(size, 4);
647
648 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
649 if (skb) {
650 if (sk_wmem_schedule(sk, skb->truesize)) {
651 /*
652 * Make sure that we have exactly size bytes
653 * available to the caller, no more, no less.
654 */
655 skb_reserve(skb, skb_tailroom(skb) - size);
656 return skb;
657 }
658 __kfree_skb(skb);
659 } else {
660 sk->sk_prot->enter_memory_pressure(sk);
661 sk_stream_moderate_sndbuf(sk);
662 }
663 return NULL;
664 }
665
666 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
667 int large_allowed)
668 {
669 struct tcp_sock *tp = tcp_sk(sk);
670 u32 xmit_size_goal, old_size_goal;
671
672 xmit_size_goal = mss_now;
673
674 if (large_allowed && sk_can_gso(sk)) {
675 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
676 inet_csk(sk)->icsk_af_ops->net_header_len -
677 inet_csk(sk)->icsk_ext_hdr_len -
678 tp->tcp_header_len);
679
680 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
681
682 /* We try hard to avoid divides here */
683 old_size_goal = tp->xmit_size_goal_segs * mss_now;
684
685 if (likely(old_size_goal <= xmit_size_goal &&
686 old_size_goal + mss_now > xmit_size_goal)) {
687 xmit_size_goal = old_size_goal;
688 } else {
689 tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
690 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
691 }
692 }
693
694 return max(xmit_size_goal, mss_now);
695 }
696
697 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
698 {
699 int mss_now;
700
701 mss_now = tcp_current_mss(sk);
702 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
703
704 return mss_now;
705 }
706
707 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
708 size_t psize, int flags)
709 {
710 struct tcp_sock *tp = tcp_sk(sk);
711 int mss_now, size_goal;
712 int err;
713 ssize_t copied;
714 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
715
716 /* Wait for a connection to finish. */
717 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
718 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
719 goto out_err;
720
721 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
722
723 mss_now = tcp_send_mss(sk, &size_goal, flags);
724 copied = 0;
725
726 err = -EPIPE;
727 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
728 goto out_err;
729
730 while (psize > 0) {
731 struct sk_buff *skb = tcp_write_queue_tail(sk);
732 struct page *page = pages[poffset / PAGE_SIZE];
733 int copy, i, can_coalesce;
734 int offset = poffset % PAGE_SIZE;
735 int size = min_t(size_t, psize, PAGE_SIZE - offset);
736
737 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
738 new_segment:
739 if (!sk_stream_memory_free(sk))
740 goto wait_for_sndbuf;
741
742 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
743 if (!skb)
744 goto wait_for_memory;
745
746 skb_entail(sk, skb);
747 copy = size_goal;
748 }
749
750 if (copy > size)
751 copy = size;
752
753 i = skb_shinfo(skb)->nr_frags;
754 can_coalesce = skb_can_coalesce(skb, i, page, offset);
755 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
756 tcp_mark_push(tp, skb);
757 goto new_segment;
758 }
759 if (!sk_wmem_schedule(sk, copy))
760 goto wait_for_memory;
761
762 if (can_coalesce) {
763 skb_shinfo(skb)->frags[i - 1].size += copy;
764 } else {
765 get_page(page);
766 skb_fill_page_desc(skb, i, page, offset, copy);
767 }
768
769 skb->len += copy;
770 skb->data_len += copy;
771 skb->truesize += copy;
772 sk->sk_wmem_queued += copy;
773 sk_mem_charge(sk, copy);
774 skb->ip_summed = CHECKSUM_PARTIAL;
775 tp->write_seq += copy;
776 TCP_SKB_CB(skb)->end_seq += copy;
777 skb_shinfo(skb)->gso_segs = 0;
778
779 if (!copied)
780 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
781
782 copied += copy;
783 poffset += copy;
784 if (!(psize -= copy))
785 goto out;
786
787 if (skb->len < size_goal || (flags & MSG_OOB))
788 continue;
789
790 if (forced_push(tp)) {
791 tcp_mark_push(tp, skb);
792 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
793 } else if (skb == tcp_send_head(sk))
794 tcp_push_one(sk, mss_now);
795 continue;
796
797 wait_for_sndbuf:
798 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
799 wait_for_memory:
800 if (copied)
801 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
802
803 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
804 goto do_error;
805
806 mss_now = tcp_send_mss(sk, &size_goal, flags);
807 }
808
809 out:
810 if (copied)
811 tcp_push(sk, flags, mss_now, tp->nonagle);
812 return copied;
813
814 do_error:
815 if (copied)
816 goto out;
817 out_err:
818 return sk_stream_error(sk, flags, err);
819 }
820
821 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
822 size_t size, int flags)
823 {
824 ssize_t res;
825 struct sock *sk = sock->sk;
826
827 if (!(sk->sk_route_caps & NETIF_F_SG) ||
828 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
829 return sock_no_sendpage(sock, page, offset, size, flags);
830
831 lock_sock(sk);
832 TCP_CHECK_TIMER(sk);
833 res = do_tcp_sendpages(sk, &page, offset, size, flags);
834 TCP_CHECK_TIMER(sk);
835 release_sock(sk);
836 return res;
837 }
838
839 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
840 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
841
842 static inline int select_size(struct sock *sk)
843 {
844 struct tcp_sock *tp = tcp_sk(sk);
845 int tmp = tp->mss_cache;
846
847 if (sk->sk_route_caps & NETIF_F_SG) {
848 if (sk_can_gso(sk))
849 tmp = 0;
850 else {
851 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
852
853 if (tmp >= pgbreak &&
854 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
855 tmp = pgbreak;
856 }
857 }
858
859 return tmp;
860 }
861
862 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
863 size_t size)
864 {
865 struct sock *sk = sock->sk;
866 struct iovec *iov;
867 struct tcp_sock *tp = tcp_sk(sk);
868 struct sk_buff *skb;
869 int iovlen, flags;
870 int mss_now, size_goal;
871 int err, copied;
872 long timeo;
873
874 lock_sock(sk);
875 TCP_CHECK_TIMER(sk);
876
877 flags = msg->msg_flags;
878 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
879
880 /* Wait for a connection to finish. */
881 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
882 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
883 goto out_err;
884
885 /* This should be in poll */
886 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
887
888 mss_now = tcp_send_mss(sk, &size_goal, flags);
889
890 /* Ok commence sending. */
891 iovlen = msg->msg_iovlen;
892 iov = msg->msg_iov;
893 copied = 0;
894
895 err = -EPIPE;
896 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
897 goto out_err;
898
899 while (--iovlen >= 0) {
900 int seglen = iov->iov_len;
901 unsigned char __user *from = iov->iov_base;
902
903 iov++;
904
905 while (seglen > 0) {
906 int copy = 0;
907 int max = size_goal;
908
909 skb = tcp_write_queue_tail(sk);
910 if (tcp_send_head(sk)) {
911 if (skb->ip_summed == CHECKSUM_NONE)
912 max = mss_now;
913 copy = max - skb->len;
914 }
915
916 if (copy <= 0) {
917 new_segment:
918 /* Allocate new segment. If the interface is SG,
919 * allocate skb fitting to single page.
920 */
921 if (!sk_stream_memory_free(sk))
922 goto wait_for_sndbuf;
923
924 skb = sk_stream_alloc_skb(sk, select_size(sk),
925 sk->sk_allocation);
926 if (!skb)
927 goto wait_for_memory;
928
929 /*
930 * Check whether we can use HW checksum.
931 */
932 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
933 skb->ip_summed = CHECKSUM_PARTIAL;
934
935 skb_entail(sk, skb);
936 copy = size_goal;
937 max = size_goal;
938 }
939
940 /* Try to append data to the end of skb. */
941 if (copy > seglen)
942 copy = seglen;
943
944 /* Where to copy to? */
945 if (skb_tailroom(skb) > 0) {
946 /* We have some space in skb head. Superb! */
947 if (copy > skb_tailroom(skb))
948 copy = skb_tailroom(skb);
949 if ((err = skb_add_data(skb, from, copy)) != 0)
950 goto do_fault;
951 } else {
952 int merge = 0;
953 int i = skb_shinfo(skb)->nr_frags;
954 struct page *page = TCP_PAGE(sk);
955 int off = TCP_OFF(sk);
956
957 if (skb_can_coalesce(skb, i, page, off) &&
958 off != PAGE_SIZE) {
959 /* We can extend the last page
960 * fragment. */
961 merge = 1;
962 } else if (i == MAX_SKB_FRAGS ||
963 (!i &&
964 !(sk->sk_route_caps & NETIF_F_SG))) {
965 /* Need to add new fragment and cannot
966 * do this because interface is non-SG,
967 * or because all the page slots are
968 * busy. */
969 tcp_mark_push(tp, skb);
970 goto new_segment;
971 } else if (page) {
972 if (off == PAGE_SIZE) {
973 put_page(page);
974 TCP_PAGE(sk) = page = NULL;
975 off = 0;
976 }
977 } else
978 off = 0;
979
980 if (copy > PAGE_SIZE - off)
981 copy = PAGE_SIZE - off;
982
983 if (!sk_wmem_schedule(sk, copy))
984 goto wait_for_memory;
985
986 if (!page) {
987 /* Allocate new cache page. */
988 if (!(page = sk_stream_alloc_page(sk)))
989 goto wait_for_memory;
990 }
991
992 /* Time to copy data. We are close to
993 * the end! */
994 err = skb_copy_to_page(sk, from, skb, page,
995 off, copy);
996 if (err) {
997 /* If this page was new, give it to the
998 * socket so it does not get leaked.
999 */
1000 if (!TCP_PAGE(sk)) {
1001 TCP_PAGE(sk) = page;
1002 TCP_OFF(sk) = 0;
1003 }
1004 goto do_error;
1005 }
1006
1007 /* Update the skb. */
1008 if (merge) {
1009 skb_shinfo(skb)->frags[i - 1].size +=
1010 copy;
1011 } else {
1012 skb_fill_page_desc(skb, i, page, off, copy);
1013 if (TCP_PAGE(sk)) {
1014 get_page(page);
1015 } else if (off + copy < PAGE_SIZE) {
1016 get_page(page);
1017 TCP_PAGE(sk) = page;
1018 }
1019 }
1020
1021 TCP_OFF(sk) = off + copy;
1022 }
1023
1024 if (!copied)
1025 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
1026
1027 tp->write_seq += copy;
1028 TCP_SKB_CB(skb)->end_seq += copy;
1029 skb_shinfo(skb)->gso_segs = 0;
1030
1031 from += copy;
1032 copied += copy;
1033 if ((seglen -= copy) == 0 && iovlen == 0)
1034 goto out;
1035
1036 if (skb->len < max || (flags & MSG_OOB))
1037 continue;
1038
1039 if (forced_push(tp)) {
1040 tcp_mark_push(tp, skb);
1041 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1042 } else if (skb == tcp_send_head(sk))
1043 tcp_push_one(sk, mss_now);
1044 continue;
1045
1046 wait_for_sndbuf:
1047 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1048 wait_for_memory:
1049 if (copied)
1050 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1051
1052 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1053 goto do_error;
1054
1055 mss_now = tcp_send_mss(sk, &size_goal, flags);
1056 }
1057 }
1058
1059 out:
1060 if (copied)
1061 tcp_push(sk, flags, mss_now, tp->nonagle);
1062 TCP_CHECK_TIMER(sk);
1063 release_sock(sk);
1064 return copied;
1065
1066 do_fault:
1067 if (!skb->len) {
1068 tcp_unlink_write_queue(skb, sk);
1069 /* It is the one place in all of TCP, except connection
1070 * reset, where we can be unlinking the send_head.
1071 */
1072 tcp_check_send_head(sk, skb);
1073 sk_wmem_free_skb(sk, skb);
1074 }
1075
1076 do_error:
1077 if (copied)
1078 goto out;
1079 out_err:
1080 err = sk_stream_error(sk, flags, err);
1081 TCP_CHECK_TIMER(sk);
1082 release_sock(sk);
1083 return err;
1084 }
1085
1086 /*
1087 * Handle reading urgent data. BSD has very simple semantics for
1088 * this, no blocking and very strange errors 8)
1089 */
1090
1091 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1092 {
1093 struct tcp_sock *tp = tcp_sk(sk);
1094
1095 /* No URG data to read. */
1096 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1097 tp->urg_data == TCP_URG_READ)
1098 return -EINVAL; /* Yes this is right ! */
1099
1100 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1101 return -ENOTCONN;
1102
1103 if (tp->urg_data & TCP_URG_VALID) {
1104 int err = 0;
1105 char c = tp->urg_data;
1106
1107 if (!(flags & MSG_PEEK))
1108 tp->urg_data = TCP_URG_READ;
1109
1110 /* Read urgent data. */
1111 msg->msg_flags |= MSG_OOB;
1112
1113 if (len > 0) {
1114 if (!(flags & MSG_TRUNC))
1115 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1116 len = 1;
1117 } else
1118 msg->msg_flags |= MSG_TRUNC;
1119
1120 return err ? -EFAULT : len;
1121 }
1122
1123 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1124 return 0;
1125
1126 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1127 * the available implementations agree in this case:
1128 * this call should never block, independent of the
1129 * blocking state of the socket.
1130 * Mike <pall@rz.uni-karlsruhe.de>
1131 */
1132 return -EAGAIN;
1133 }
1134
1135 /* Clean up the receive buffer for full frames taken by the user,
1136 * then send an ACK if necessary. COPIED is the number of bytes
1137 * tcp_recvmsg has given to the user so far, it speeds up the
1138 * calculation of whether or not we must ACK for the sake of
1139 * a window update.
1140 */
1141 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1142 {
1143 struct tcp_sock *tp = tcp_sk(sk);
1144 int time_to_ack = 0;
1145
1146 #if TCP_DEBUG
1147 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1148
1149 WARN_ON(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
1150 #endif
1151
1152 if (inet_csk_ack_scheduled(sk)) {
1153 const struct inet_connection_sock *icsk = inet_csk(sk);
1154 /* Delayed ACKs frequently hit locked sockets during bulk
1155 * receive. */
1156 if (icsk->icsk_ack.blocked ||
1157 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1158 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1159 /*
1160 * If this read emptied read buffer, we send ACK, if
1161 * connection is not bidirectional, user drained
1162 * receive buffer and there was a small segment
1163 * in queue.
1164 */
1165 (copied > 0 &&
1166 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1167 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1168 !icsk->icsk_ack.pingpong)) &&
1169 !atomic_read(&sk->sk_rmem_alloc)))
1170 time_to_ack = 1;
1171 }
1172
1173 /* We send an ACK if we can now advertise a non-zero window
1174 * which has been raised "significantly".
1175 *
1176 * Even if window raised up to infinity, do not send window open ACK
1177 * in states, where we will not receive more. It is useless.
1178 */
1179 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1180 __u32 rcv_window_now = tcp_receive_window(tp);
1181
1182 /* Optimize, __tcp_select_window() is not cheap. */
1183 if (2*rcv_window_now <= tp->window_clamp) {
1184 __u32 new_window = __tcp_select_window(sk);
1185
1186 /* Send ACK now, if this read freed lots of space
1187 * in our buffer. Certainly, new_window is new window.
1188 * We can advertise it now, if it is not less than current one.
1189 * "Lots" means "at least twice" here.
1190 */
1191 if (new_window && new_window >= 2 * rcv_window_now)
1192 time_to_ack = 1;
1193 }
1194 }
1195 if (time_to_ack)
1196 tcp_send_ack(sk);
1197 }
1198
1199 static void tcp_prequeue_process(struct sock *sk)
1200 {
1201 struct sk_buff *skb;
1202 struct tcp_sock *tp = tcp_sk(sk);
1203
1204 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1205
1206 /* RX process wants to run with disabled BHs, though it is not
1207 * necessary */
1208 local_bh_disable();
1209 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1210 sk_backlog_rcv(sk, skb);
1211 local_bh_enable();
1212
1213 /* Clear memory counter. */
1214 tp->ucopy.memory = 0;
1215 }
1216
1217 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1218 {
1219 struct sk_buff *skb;
1220 u32 offset;
1221
1222 skb_queue_walk(&sk->sk_receive_queue, skb) {
1223 offset = seq - TCP_SKB_CB(skb)->seq;
1224 if (tcp_hdr(skb)->syn)
1225 offset--;
1226 if (offset < skb->len || tcp_hdr(skb)->fin) {
1227 *off = offset;
1228 return skb;
1229 }
1230 }
1231 return NULL;
1232 }
1233
1234 /*
1235 * This routine provides an alternative to tcp_recvmsg() for routines
1236 * that would like to handle copying from skbuffs directly in 'sendfile'
1237 * fashion.
1238 * Note:
1239 * - It is assumed that the socket was locked by the caller.
1240 * - The routine does not block.
1241 * - At present, there is no support for reading OOB data
1242 * or for 'peeking' the socket using this routine
1243 * (although both would be easy to implement).
1244 */
1245 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1246 sk_read_actor_t recv_actor)
1247 {
1248 struct sk_buff *skb;
1249 struct tcp_sock *tp = tcp_sk(sk);
1250 u32 seq = tp->copied_seq;
1251 u32 offset;
1252 int copied = 0;
1253
1254 if (sk->sk_state == TCP_LISTEN)
1255 return -ENOTCONN;
1256 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1257 if (offset < skb->len) {
1258 int used;
1259 size_t len;
1260
1261 len = skb->len - offset;
1262 /* Stop reading if we hit a patch of urgent data */
1263 if (tp->urg_data) {
1264 u32 urg_offset = tp->urg_seq - seq;
1265 if (urg_offset < len)
1266 len = urg_offset;
1267 if (!len)
1268 break;
1269 }
1270 used = recv_actor(desc, skb, offset, len);
1271 if (used < 0) {
1272 if (!copied)
1273 copied = used;
1274 break;
1275 } else if (used <= len) {
1276 seq += used;
1277 copied += used;
1278 offset += used;
1279 }
1280 /*
1281 * If recv_actor drops the lock (e.g. TCP splice
1282 * receive) the skb pointer might be invalid when
1283 * getting here: tcp_collapse might have deleted it
1284 * while aggregating skbs from the socket queue.
1285 */
1286 skb = tcp_recv_skb(sk, seq-1, &offset);
1287 if (!skb || (offset+1 != skb->len))
1288 break;
1289 }
1290 if (tcp_hdr(skb)->fin) {
1291 sk_eat_skb(sk, skb, 0);
1292 ++seq;
1293 break;
1294 }
1295 sk_eat_skb(sk, skb, 0);
1296 if (!desc->count)
1297 break;
1298 }
1299 tp->copied_seq = seq;
1300
1301 tcp_rcv_space_adjust(sk);
1302
1303 /* Clean up data we have read: This will do ACK frames. */
1304 if (copied > 0)
1305 tcp_cleanup_rbuf(sk, copied);
1306 return copied;
1307 }
1308
1309 /*
1310 * This routine copies from a sock struct into the user buffer.
1311 *
1312 * Technical note: in 2.3 we work on _locked_ socket, so that
1313 * tricks with *seq access order and skb->users are not required.
1314 * Probably, code can be easily improved even more.
1315 */
1316
1317 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1318 size_t len, int nonblock, int flags, int *addr_len)
1319 {
1320 struct tcp_sock *tp = tcp_sk(sk);
1321 int copied = 0;
1322 u32 peek_seq;
1323 u32 *seq;
1324 unsigned long used;
1325 int err;
1326 int target; /* Read at least this many bytes */
1327 long timeo;
1328 struct task_struct *user_recv = NULL;
1329 int copied_early = 0;
1330 struct sk_buff *skb;
1331 u32 urg_hole = 0;
1332
1333 lock_sock(sk);
1334
1335 TCP_CHECK_TIMER(sk);
1336
1337 err = -ENOTCONN;
1338 if (sk->sk_state == TCP_LISTEN)
1339 goto out;
1340
1341 timeo = sock_rcvtimeo(sk, nonblock);
1342
1343 /* Urgent data needs to be handled specially. */
1344 if (flags & MSG_OOB)
1345 goto recv_urg;
1346
1347 seq = &tp->copied_seq;
1348 if (flags & MSG_PEEK) {
1349 peek_seq = tp->copied_seq;
1350 seq = &peek_seq;
1351 }
1352
1353 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1354
1355 #ifdef CONFIG_NET_DMA
1356 tp->ucopy.dma_chan = NULL;
1357 preempt_disable();
1358 skb = skb_peek_tail(&sk->sk_receive_queue);
1359 {
1360 int available = 0;
1361
1362 if (skb)
1363 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1364 if ((available < target) &&
1365 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1366 !sysctl_tcp_low_latency &&
1367 dma_find_channel(DMA_MEMCPY)) {
1368 preempt_enable_no_resched();
1369 tp->ucopy.pinned_list =
1370 dma_pin_iovec_pages(msg->msg_iov, len);
1371 } else {
1372 preempt_enable_no_resched();
1373 }
1374 }
1375 #endif
1376
1377 do {
1378 u32 offset;
1379
1380 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1381 if (tp->urg_data && tp->urg_seq == *seq) {
1382 if (copied)
1383 break;
1384 if (signal_pending(current)) {
1385 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1386 break;
1387 }
1388 }
1389
1390 /* Next get a buffer. */
1391
1392 skb_queue_walk(&sk->sk_receive_queue, skb) {
1393 /* Now that we have two receive queues this
1394 * shouldn't happen.
1395 */
1396 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1397 printk(KERN_INFO "recvmsg bug: copied %X "
1398 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1399 break;
1400 }
1401 offset = *seq - TCP_SKB_CB(skb)->seq;
1402 if (tcp_hdr(skb)->syn)
1403 offset--;
1404 if (offset < skb->len)
1405 goto found_ok_skb;
1406 if (tcp_hdr(skb)->fin)
1407 goto found_fin_ok;
1408 WARN_ON(!(flags & MSG_PEEK));
1409 }
1410
1411 /* Well, if we have backlog, try to process it now yet. */
1412
1413 if (copied >= target && !sk->sk_backlog.tail)
1414 break;
1415
1416 if (copied) {
1417 if (sk->sk_err ||
1418 sk->sk_state == TCP_CLOSE ||
1419 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1420 !timeo ||
1421 signal_pending(current))
1422 break;
1423 } else {
1424 if (sock_flag(sk, SOCK_DONE))
1425 break;
1426
1427 if (sk->sk_err) {
1428 copied = sock_error(sk);
1429 break;
1430 }
1431
1432 if (sk->sk_shutdown & RCV_SHUTDOWN)
1433 break;
1434
1435 if (sk->sk_state == TCP_CLOSE) {
1436 if (!sock_flag(sk, SOCK_DONE)) {
1437 /* This occurs when user tries to read
1438 * from never connected socket.
1439 */
1440 copied = -ENOTCONN;
1441 break;
1442 }
1443 break;
1444 }
1445
1446 if (!timeo) {
1447 copied = -EAGAIN;
1448 break;
1449 }
1450
1451 if (signal_pending(current)) {
1452 copied = sock_intr_errno(timeo);
1453 break;
1454 }
1455 }
1456
1457 tcp_cleanup_rbuf(sk, copied);
1458
1459 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1460 /* Install new reader */
1461 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1462 user_recv = current;
1463 tp->ucopy.task = user_recv;
1464 tp->ucopy.iov = msg->msg_iov;
1465 }
1466
1467 tp->ucopy.len = len;
1468
1469 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1470 !(flags & (MSG_PEEK | MSG_TRUNC)));
1471
1472 /* Ugly... If prequeue is not empty, we have to
1473 * process it before releasing socket, otherwise
1474 * order will be broken at second iteration.
1475 * More elegant solution is required!!!
1476 *
1477 * Look: we have the following (pseudo)queues:
1478 *
1479 * 1. packets in flight
1480 * 2. backlog
1481 * 3. prequeue
1482 * 4. receive_queue
1483 *
1484 * Each queue can be processed only if the next ones
1485 * are empty. At this point we have empty receive_queue.
1486 * But prequeue _can_ be not empty after 2nd iteration,
1487 * when we jumped to start of loop because backlog
1488 * processing added something to receive_queue.
1489 * We cannot release_sock(), because backlog contains
1490 * packets arrived _after_ prequeued ones.
1491 *
1492 * Shortly, algorithm is clear --- to process all
1493 * the queues in order. We could make it more directly,
1494 * requeueing packets from backlog to prequeue, if
1495 * is not empty. It is more elegant, but eats cycles,
1496 * unfortunately.
1497 */
1498 if (!skb_queue_empty(&tp->ucopy.prequeue))
1499 goto do_prequeue;
1500
1501 /* __ Set realtime policy in scheduler __ */
1502 }
1503
1504 if (copied >= target) {
1505 /* Do not sleep, just process backlog. */
1506 release_sock(sk);
1507 lock_sock(sk);
1508 } else
1509 sk_wait_data(sk, &timeo);
1510
1511 #ifdef CONFIG_NET_DMA
1512 tp->ucopy.wakeup = 0;
1513 #endif
1514
1515 if (user_recv) {
1516 int chunk;
1517
1518 /* __ Restore normal policy in scheduler __ */
1519
1520 if ((chunk = len - tp->ucopy.len) != 0) {
1521 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1522 len -= chunk;
1523 copied += chunk;
1524 }
1525
1526 if (tp->rcv_nxt == tp->copied_seq &&
1527 !skb_queue_empty(&tp->ucopy.prequeue)) {
1528 do_prequeue:
1529 tcp_prequeue_process(sk);
1530
1531 if ((chunk = len - tp->ucopy.len) != 0) {
1532 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1533 len -= chunk;
1534 copied += chunk;
1535 }
1536 }
1537 }
1538 if ((flags & MSG_PEEK) &&
1539 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1540 if (net_ratelimit())
1541 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1542 current->comm, task_pid_nr(current));
1543 peek_seq = tp->copied_seq;
1544 }
1545 continue;
1546
1547 found_ok_skb:
1548 /* Ok so how much can we use? */
1549 used = skb->len - offset;
1550 if (len < used)
1551 used = len;
1552
1553 /* Do we have urgent data here? */
1554 if (tp->urg_data) {
1555 u32 urg_offset = tp->urg_seq - *seq;
1556 if (urg_offset < used) {
1557 if (!urg_offset) {
1558 if (!sock_flag(sk, SOCK_URGINLINE)) {
1559 ++*seq;
1560 urg_hole++;
1561 offset++;
1562 used--;
1563 if (!used)
1564 goto skip_copy;
1565 }
1566 } else
1567 used = urg_offset;
1568 }
1569 }
1570
1571 if (!(flags & MSG_TRUNC)) {
1572 #ifdef CONFIG_NET_DMA
1573 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1574 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1575
1576 if (tp->ucopy.dma_chan) {
1577 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1578 tp->ucopy.dma_chan, skb, offset,
1579 msg->msg_iov, used,
1580 tp->ucopy.pinned_list);
1581
1582 if (tp->ucopy.dma_cookie < 0) {
1583
1584 printk(KERN_ALERT "dma_cookie < 0\n");
1585
1586 /* Exception. Bailout! */
1587 if (!copied)
1588 copied = -EFAULT;
1589 break;
1590 }
1591 if ((offset + used) == skb->len)
1592 copied_early = 1;
1593
1594 } else
1595 #endif
1596 {
1597 err = skb_copy_datagram_iovec(skb, offset,
1598 msg->msg_iov, used);
1599 if (err) {
1600 /* Exception. Bailout! */
1601 if (!copied)
1602 copied = -EFAULT;
1603 break;
1604 }
1605 }
1606 }
1607
1608 *seq += used;
1609 copied += used;
1610 len -= used;
1611
1612 tcp_rcv_space_adjust(sk);
1613
1614 skip_copy:
1615 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1616 tp->urg_data = 0;
1617 tcp_fast_path_check(sk);
1618 }
1619 if (used + offset < skb->len)
1620 continue;
1621
1622 if (tcp_hdr(skb)->fin)
1623 goto found_fin_ok;
1624 if (!(flags & MSG_PEEK)) {
1625 sk_eat_skb(sk, skb, copied_early);
1626 copied_early = 0;
1627 }
1628 continue;
1629
1630 found_fin_ok:
1631 /* Process the FIN. */
1632 ++*seq;
1633 if (!(flags & MSG_PEEK)) {
1634 sk_eat_skb(sk, skb, copied_early);
1635 copied_early = 0;
1636 }
1637 break;
1638 } while (len > 0);
1639
1640 if (user_recv) {
1641 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1642 int chunk;
1643
1644 tp->ucopy.len = copied > 0 ? len : 0;
1645
1646 tcp_prequeue_process(sk);
1647
1648 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1649 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1650 len -= chunk;
1651 copied += chunk;
1652 }
1653 }
1654
1655 tp->ucopy.task = NULL;
1656 tp->ucopy.len = 0;
1657 }
1658
1659 #ifdef CONFIG_NET_DMA
1660 if (tp->ucopy.dma_chan) {
1661 dma_cookie_t done, used;
1662
1663 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1664
1665 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1666 tp->ucopy.dma_cookie, &done,
1667 &used) == DMA_IN_PROGRESS) {
1668 /* do partial cleanup of sk_async_wait_queue */
1669 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1670 (dma_async_is_complete(skb->dma_cookie, done,
1671 used) == DMA_SUCCESS)) {
1672 __skb_dequeue(&sk->sk_async_wait_queue);
1673 kfree_skb(skb);
1674 }
1675 }
1676
1677 /* Safe to free early-copied skbs now */
1678 __skb_queue_purge(&sk->sk_async_wait_queue);
1679 tp->ucopy.dma_chan = NULL;
1680 }
1681 if (tp->ucopy.pinned_list) {
1682 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1683 tp->ucopy.pinned_list = NULL;
1684 }
1685 #endif
1686
1687 /* According to UNIX98, msg_name/msg_namelen are ignored
1688 * on connected socket. I was just happy when found this 8) --ANK
1689 */
1690
1691 /* Clean up data we have read: This will do ACK frames. */
1692 tcp_cleanup_rbuf(sk, copied);
1693
1694 TCP_CHECK_TIMER(sk);
1695 release_sock(sk);
1696 return copied;
1697
1698 out:
1699 TCP_CHECK_TIMER(sk);
1700 release_sock(sk);
1701 return err;
1702
1703 recv_urg:
1704 err = tcp_recv_urg(sk, msg, len, flags);
1705 goto out;
1706 }
1707
1708 void tcp_set_state(struct sock *sk, int state)
1709 {
1710 int oldstate = sk->sk_state;
1711
1712 switch (state) {
1713 case TCP_ESTABLISHED:
1714 if (oldstate != TCP_ESTABLISHED)
1715 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1716 break;
1717
1718 case TCP_CLOSE:
1719 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1720 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1721
1722 sk->sk_prot->unhash(sk);
1723 if (inet_csk(sk)->icsk_bind_hash &&
1724 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1725 inet_put_port(sk);
1726 /* fall through */
1727 default:
1728 if (oldstate == TCP_ESTABLISHED)
1729 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1730 }
1731
1732 /* Change state AFTER socket is unhashed to avoid closed
1733 * socket sitting in hash tables.
1734 */
1735 sk->sk_state = state;
1736
1737 #ifdef STATE_TRACE
1738 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1739 #endif
1740 }
1741 EXPORT_SYMBOL_GPL(tcp_set_state);
1742
1743 /*
1744 * State processing on a close. This implements the state shift for
1745 * sending our FIN frame. Note that we only send a FIN for some
1746 * states. A shutdown() may have already sent the FIN, or we may be
1747 * closed.
1748 */
1749
1750 static const unsigned char new_state[16] = {
1751 /* current state: new state: action: */
1752 /* (Invalid) */ TCP_CLOSE,
1753 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1754 /* TCP_SYN_SENT */ TCP_CLOSE,
1755 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1756 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1757 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1758 /* TCP_TIME_WAIT */ TCP_CLOSE,
1759 /* TCP_CLOSE */ TCP_CLOSE,
1760 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1761 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1762 /* TCP_LISTEN */ TCP_CLOSE,
1763 /* TCP_CLOSING */ TCP_CLOSING,
1764 };
1765
1766 static int tcp_close_state(struct sock *sk)
1767 {
1768 int next = (int)new_state[sk->sk_state];
1769 int ns = next & TCP_STATE_MASK;
1770
1771 tcp_set_state(sk, ns);
1772
1773 return next & TCP_ACTION_FIN;
1774 }
1775
1776 /*
1777 * Shutdown the sending side of a connection. Much like close except
1778 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1779 */
1780
1781 void tcp_shutdown(struct sock *sk, int how)
1782 {
1783 /* We need to grab some memory, and put together a FIN,
1784 * and then put it into the queue to be sent.
1785 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1786 */
1787 if (!(how & SEND_SHUTDOWN))
1788 return;
1789
1790 /* If we've already sent a FIN, or it's a closed state, skip this. */
1791 if ((1 << sk->sk_state) &
1792 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1793 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1794 /* Clear out any half completed packets. FIN if needed. */
1795 if (tcp_close_state(sk))
1796 tcp_send_fin(sk);
1797 }
1798 }
1799
1800 void tcp_close(struct sock *sk, long timeout)
1801 {
1802 struct sk_buff *skb;
1803 int data_was_unread = 0;
1804 int state;
1805
1806 lock_sock(sk);
1807 sk->sk_shutdown = SHUTDOWN_MASK;
1808
1809 if (sk->sk_state == TCP_LISTEN) {
1810 tcp_set_state(sk, TCP_CLOSE);
1811
1812 /* Special case. */
1813 inet_csk_listen_stop(sk);
1814
1815 goto adjudge_to_death;
1816 }
1817
1818 /* We need to flush the recv. buffs. We do this only on the
1819 * descriptor close, not protocol-sourced closes, because the
1820 * reader process may not have drained the data yet!
1821 */
1822 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1823 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1824 tcp_hdr(skb)->fin;
1825 data_was_unread += len;
1826 __kfree_skb(skb);
1827 }
1828
1829 sk_mem_reclaim(sk);
1830
1831 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1832 * data was lost. To witness the awful effects of the old behavior of
1833 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1834 * GET in an FTP client, suspend the process, wait for the client to
1835 * advertise a zero window, then kill -9 the FTP client, wheee...
1836 * Note: timeout is always zero in such a case.
1837 */
1838 if (data_was_unread) {
1839 /* Unread data was tossed, zap the connection. */
1840 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1841 tcp_set_state(sk, TCP_CLOSE);
1842 tcp_send_active_reset(sk, GFP_KERNEL);
1843 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1844 /* Check zero linger _after_ checking for unread data. */
1845 sk->sk_prot->disconnect(sk, 0);
1846 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1847 } else if (tcp_close_state(sk)) {
1848 /* We FIN if the application ate all the data before
1849 * zapping the connection.
1850 */
1851
1852 /* RED-PEN. Formally speaking, we have broken TCP state
1853 * machine. State transitions:
1854 *
1855 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1856 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1857 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1858 *
1859 * are legal only when FIN has been sent (i.e. in window),
1860 * rather than queued out of window. Purists blame.
1861 *
1862 * F.e. "RFC state" is ESTABLISHED,
1863 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1864 *
1865 * The visible declinations are that sometimes
1866 * we enter time-wait state, when it is not required really
1867 * (harmless), do not send active resets, when they are
1868 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1869 * they look as CLOSING or LAST_ACK for Linux)
1870 * Probably, I missed some more holelets.
1871 * --ANK
1872 */
1873 tcp_send_fin(sk);
1874 }
1875
1876 sk_stream_wait_close(sk, timeout);
1877
1878 adjudge_to_death:
1879 state = sk->sk_state;
1880 sock_hold(sk);
1881 sock_orphan(sk);
1882
1883 /* It is the last release_sock in its life. It will remove backlog. */
1884 release_sock(sk);
1885
1886
1887 /* Now socket is owned by kernel and we acquire BH lock
1888 to finish close. No need to check for user refs.
1889 */
1890 local_bh_disable();
1891 bh_lock_sock(sk);
1892 WARN_ON(sock_owned_by_user(sk));
1893
1894 percpu_counter_inc(sk->sk_prot->orphan_count);
1895
1896 /* Have we already been destroyed by a softirq or backlog? */
1897 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1898 goto out;
1899
1900 /* This is a (useful) BSD violating of the RFC. There is a
1901 * problem with TCP as specified in that the other end could
1902 * keep a socket open forever with no application left this end.
1903 * We use a 3 minute timeout (about the same as BSD) then kill
1904 * our end. If they send after that then tough - BUT: long enough
1905 * that we won't make the old 4*rto = almost no time - whoops
1906 * reset mistake.
1907 *
1908 * Nope, it was not mistake. It is really desired behaviour
1909 * f.e. on http servers, when such sockets are useless, but
1910 * consume significant resources. Let's do it with special
1911 * linger2 option. --ANK
1912 */
1913
1914 if (sk->sk_state == TCP_FIN_WAIT2) {
1915 struct tcp_sock *tp = tcp_sk(sk);
1916 if (tp->linger2 < 0) {
1917 tcp_set_state(sk, TCP_CLOSE);
1918 tcp_send_active_reset(sk, GFP_ATOMIC);
1919 NET_INC_STATS_BH(sock_net(sk),
1920 LINUX_MIB_TCPABORTONLINGER);
1921 } else {
1922 const int tmo = tcp_fin_time(sk);
1923
1924 if (tmo > TCP_TIMEWAIT_LEN) {
1925 inet_csk_reset_keepalive_timer(sk,
1926 tmo - TCP_TIMEWAIT_LEN);
1927 } else {
1928 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1929 goto out;
1930 }
1931 }
1932 }
1933 if (sk->sk_state != TCP_CLOSE) {
1934 int orphan_count = percpu_counter_read_positive(
1935 sk->sk_prot->orphan_count);
1936
1937 sk_mem_reclaim(sk);
1938 if (tcp_too_many_orphans(sk, orphan_count)) {
1939 if (net_ratelimit())
1940 printk(KERN_INFO "TCP: too many of orphaned "
1941 "sockets\n");
1942 tcp_set_state(sk, TCP_CLOSE);
1943 tcp_send_active_reset(sk, GFP_ATOMIC);
1944 NET_INC_STATS_BH(sock_net(sk),
1945 LINUX_MIB_TCPABORTONMEMORY);
1946 }
1947 }
1948
1949 if (sk->sk_state == TCP_CLOSE)
1950 inet_csk_destroy_sock(sk);
1951 /* Otherwise, socket is reprieved until protocol close. */
1952
1953 out:
1954 bh_unlock_sock(sk);
1955 local_bh_enable();
1956 sock_put(sk);
1957 }
1958
1959 /* These states need RST on ABORT according to RFC793 */
1960
1961 static inline int tcp_need_reset(int state)
1962 {
1963 return (1 << state) &
1964 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1965 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1966 }
1967
1968 int tcp_disconnect(struct sock *sk, int flags)
1969 {
1970 struct inet_sock *inet = inet_sk(sk);
1971 struct inet_connection_sock *icsk = inet_csk(sk);
1972 struct tcp_sock *tp = tcp_sk(sk);
1973 int err = 0;
1974 int old_state = sk->sk_state;
1975
1976 if (old_state != TCP_CLOSE)
1977 tcp_set_state(sk, TCP_CLOSE);
1978
1979 /* ABORT function of RFC793 */
1980 if (old_state == TCP_LISTEN) {
1981 inet_csk_listen_stop(sk);
1982 } else if (tcp_need_reset(old_state) ||
1983 (tp->snd_nxt != tp->write_seq &&
1984 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1985 /* The last check adjusts for discrepancy of Linux wrt. RFC
1986 * states
1987 */
1988 tcp_send_active_reset(sk, gfp_any());
1989 sk->sk_err = ECONNRESET;
1990 } else if (old_state == TCP_SYN_SENT)
1991 sk->sk_err = ECONNRESET;
1992
1993 tcp_clear_xmit_timers(sk);
1994 __skb_queue_purge(&sk->sk_receive_queue);
1995 tcp_write_queue_purge(sk);
1996 __skb_queue_purge(&tp->out_of_order_queue);
1997 #ifdef CONFIG_NET_DMA
1998 __skb_queue_purge(&sk->sk_async_wait_queue);
1999 #endif
2000
2001 inet->dport = 0;
2002
2003 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2004 inet_reset_saddr(sk);
2005
2006 sk->sk_shutdown = 0;
2007 sock_reset_flag(sk, SOCK_DONE);
2008 tp->srtt = 0;
2009 if ((tp->write_seq += tp->max_window + 2) == 0)
2010 tp->write_seq = 1;
2011 icsk->icsk_backoff = 0;
2012 tp->snd_cwnd = 2;
2013 icsk->icsk_probes_out = 0;
2014 tp->packets_out = 0;
2015 tp->snd_ssthresh = 0x7fffffff;
2016 tp->snd_cwnd_cnt = 0;
2017 tp->bytes_acked = 0;
2018 tcp_set_ca_state(sk, TCP_CA_Open);
2019 tcp_clear_retrans(tp);
2020 inet_csk_delack_init(sk);
2021 tcp_init_send_head(sk);
2022 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2023 __sk_dst_reset(sk);
2024
2025 WARN_ON(inet->num && !icsk->icsk_bind_hash);
2026
2027 sk->sk_error_report(sk);
2028 return err;
2029 }
2030
2031 /*
2032 * Socket option code for TCP.
2033 */
2034 static int do_tcp_setsockopt(struct sock *sk, int level,
2035 int optname, char __user *optval, int optlen)
2036 {
2037 struct tcp_sock *tp = tcp_sk(sk);
2038 struct inet_connection_sock *icsk = inet_csk(sk);
2039 int val;
2040 int err = 0;
2041
2042 /* This is a string value all the others are int's */
2043 if (optname == TCP_CONGESTION) {
2044 char name[TCP_CA_NAME_MAX];
2045
2046 if (optlen < 1)
2047 return -EINVAL;
2048
2049 val = strncpy_from_user(name, optval,
2050 min(TCP_CA_NAME_MAX-1, optlen));
2051 if (val < 0)
2052 return -EFAULT;
2053 name[val] = 0;
2054
2055 lock_sock(sk);
2056 err = tcp_set_congestion_control(sk, name);
2057 release_sock(sk);
2058 return err;
2059 }
2060
2061 if (optlen < sizeof(int))
2062 return -EINVAL;
2063
2064 if (get_user(val, (int __user *)optval))
2065 return -EFAULT;
2066
2067 lock_sock(sk);
2068
2069 switch (optname) {
2070 case TCP_MAXSEG:
2071 /* Values greater than interface MTU won't take effect. However
2072 * at the point when this call is done we typically don't yet
2073 * know which interface is going to be used */
2074 if (val < 8 || val > MAX_TCP_WINDOW) {
2075 err = -EINVAL;
2076 break;
2077 }
2078 tp->rx_opt.user_mss = val;
2079 break;
2080
2081 case TCP_NODELAY:
2082 if (val) {
2083 /* TCP_NODELAY is weaker than TCP_CORK, so that
2084 * this option on corked socket is remembered, but
2085 * it is not activated until cork is cleared.
2086 *
2087 * However, when TCP_NODELAY is set we make
2088 * an explicit push, which overrides even TCP_CORK
2089 * for currently queued segments.
2090 */
2091 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2092 tcp_push_pending_frames(sk);
2093 } else {
2094 tp->nonagle &= ~TCP_NAGLE_OFF;
2095 }
2096 break;
2097
2098 case TCP_CORK:
2099 /* When set indicates to always queue non-full frames.
2100 * Later the user clears this option and we transmit
2101 * any pending partial frames in the queue. This is
2102 * meant to be used alongside sendfile() to get properly
2103 * filled frames when the user (for example) must write
2104 * out headers with a write() call first and then use
2105 * sendfile to send out the data parts.
2106 *
2107 * TCP_CORK can be set together with TCP_NODELAY and it is
2108 * stronger than TCP_NODELAY.
2109 */
2110 if (val) {
2111 tp->nonagle |= TCP_NAGLE_CORK;
2112 } else {
2113 tp->nonagle &= ~TCP_NAGLE_CORK;
2114 if (tp->nonagle&TCP_NAGLE_OFF)
2115 tp->nonagle |= TCP_NAGLE_PUSH;
2116 tcp_push_pending_frames(sk);
2117 }
2118 break;
2119
2120 case TCP_KEEPIDLE:
2121 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2122 err = -EINVAL;
2123 else {
2124 tp->keepalive_time = val * HZ;
2125 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2126 !((1 << sk->sk_state) &
2127 (TCPF_CLOSE | TCPF_LISTEN))) {
2128 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2129 if (tp->keepalive_time > elapsed)
2130 elapsed = tp->keepalive_time - elapsed;
2131 else
2132 elapsed = 0;
2133 inet_csk_reset_keepalive_timer(sk, elapsed);
2134 }
2135 }
2136 break;
2137 case TCP_KEEPINTVL:
2138 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2139 err = -EINVAL;
2140 else
2141 tp->keepalive_intvl = val * HZ;
2142 break;
2143 case TCP_KEEPCNT:
2144 if (val < 1 || val > MAX_TCP_KEEPCNT)
2145 err = -EINVAL;
2146 else
2147 tp->keepalive_probes = val;
2148 break;
2149 case TCP_SYNCNT:
2150 if (val < 1 || val > MAX_TCP_SYNCNT)
2151 err = -EINVAL;
2152 else
2153 icsk->icsk_syn_retries = val;
2154 break;
2155
2156 case TCP_LINGER2:
2157 if (val < 0)
2158 tp->linger2 = -1;
2159 else if (val > sysctl_tcp_fin_timeout / HZ)
2160 tp->linger2 = 0;
2161 else
2162 tp->linger2 = val * HZ;
2163 break;
2164
2165 case TCP_DEFER_ACCEPT:
2166 icsk->icsk_accept_queue.rskq_defer_accept = 0;
2167 if (val > 0) {
2168 /* Translate value in seconds to number of
2169 * retransmits */
2170 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
2171 val > ((TCP_TIMEOUT_INIT / HZ) <<
2172 icsk->icsk_accept_queue.rskq_defer_accept))
2173 icsk->icsk_accept_queue.rskq_defer_accept++;
2174 icsk->icsk_accept_queue.rskq_defer_accept++;
2175 }
2176 break;
2177
2178 case TCP_WINDOW_CLAMP:
2179 if (!val) {
2180 if (sk->sk_state != TCP_CLOSE) {
2181 err = -EINVAL;
2182 break;
2183 }
2184 tp->window_clamp = 0;
2185 } else
2186 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2187 SOCK_MIN_RCVBUF / 2 : val;
2188 break;
2189
2190 case TCP_QUICKACK:
2191 if (!val) {
2192 icsk->icsk_ack.pingpong = 1;
2193 } else {
2194 icsk->icsk_ack.pingpong = 0;
2195 if ((1 << sk->sk_state) &
2196 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2197 inet_csk_ack_scheduled(sk)) {
2198 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2199 tcp_cleanup_rbuf(sk, 1);
2200 if (!(val & 1))
2201 icsk->icsk_ack.pingpong = 1;
2202 }
2203 }
2204 break;
2205
2206 #ifdef CONFIG_TCP_MD5SIG
2207 case TCP_MD5SIG:
2208 /* Read the IP->Key mappings from userspace */
2209 err = tp->af_specific->md5_parse(sk, optval, optlen);
2210 break;
2211 #endif
2212
2213 default:
2214 err = -ENOPROTOOPT;
2215 break;
2216 }
2217
2218 release_sock(sk);
2219 return err;
2220 }
2221
2222 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2223 int optlen)
2224 {
2225 struct inet_connection_sock *icsk = inet_csk(sk);
2226
2227 if (level != SOL_TCP)
2228 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2229 optval, optlen);
2230 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2231 }
2232
2233 #ifdef CONFIG_COMPAT
2234 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2235 char __user *optval, int optlen)
2236 {
2237 if (level != SOL_TCP)
2238 return inet_csk_compat_setsockopt(sk, level, optname,
2239 optval, optlen);
2240 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2241 }
2242
2243 EXPORT_SYMBOL(compat_tcp_setsockopt);
2244 #endif
2245
2246 /* Return information about state of tcp endpoint in API format. */
2247 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2248 {
2249 struct tcp_sock *tp = tcp_sk(sk);
2250 const struct inet_connection_sock *icsk = inet_csk(sk);
2251 u32 now = tcp_time_stamp;
2252
2253 memset(info, 0, sizeof(*info));
2254
2255 info->tcpi_state = sk->sk_state;
2256 info->tcpi_ca_state = icsk->icsk_ca_state;
2257 info->tcpi_retransmits = icsk->icsk_retransmits;
2258 info->tcpi_probes = icsk->icsk_probes_out;
2259 info->tcpi_backoff = icsk->icsk_backoff;
2260
2261 if (tp->rx_opt.tstamp_ok)
2262 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2263 if (tcp_is_sack(tp))
2264 info->tcpi_options |= TCPI_OPT_SACK;
2265 if (tp->rx_opt.wscale_ok) {
2266 info->tcpi_options |= TCPI_OPT_WSCALE;
2267 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2268 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2269 }
2270
2271 if (tp->ecn_flags&TCP_ECN_OK)
2272 info->tcpi_options |= TCPI_OPT_ECN;
2273
2274 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2275 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2276 info->tcpi_snd_mss = tp->mss_cache;
2277 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2278
2279 if (sk->sk_state == TCP_LISTEN) {
2280 info->tcpi_unacked = sk->sk_ack_backlog;
2281 info->tcpi_sacked = sk->sk_max_ack_backlog;
2282 } else {
2283 info->tcpi_unacked = tp->packets_out;
2284 info->tcpi_sacked = tp->sacked_out;
2285 }
2286 info->tcpi_lost = tp->lost_out;
2287 info->tcpi_retrans = tp->retrans_out;
2288 info->tcpi_fackets = tp->fackets_out;
2289
2290 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2291 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2292 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2293
2294 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2295 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2296 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2297 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2298 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2299 info->tcpi_snd_cwnd = tp->snd_cwnd;
2300 info->tcpi_advmss = tp->advmss;
2301 info->tcpi_reordering = tp->reordering;
2302
2303 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2304 info->tcpi_rcv_space = tp->rcvq_space.space;
2305
2306 info->tcpi_total_retrans = tp->total_retrans;
2307 }
2308
2309 EXPORT_SYMBOL_GPL(tcp_get_info);
2310
2311 static int do_tcp_getsockopt(struct sock *sk, int level,
2312 int optname, char __user *optval, int __user *optlen)
2313 {
2314 struct inet_connection_sock *icsk = inet_csk(sk);
2315 struct tcp_sock *tp = tcp_sk(sk);
2316 int val, len;
2317
2318 if (get_user(len, optlen))
2319 return -EFAULT;
2320
2321 len = min_t(unsigned int, len, sizeof(int));
2322
2323 if (len < 0)
2324 return -EINVAL;
2325
2326 switch (optname) {
2327 case TCP_MAXSEG:
2328 val = tp->mss_cache;
2329 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2330 val = tp->rx_opt.user_mss;
2331 break;
2332 case TCP_NODELAY:
2333 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2334 break;
2335 case TCP_CORK:
2336 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2337 break;
2338 case TCP_KEEPIDLE:
2339 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2340 break;
2341 case TCP_KEEPINTVL:
2342 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2343 break;
2344 case TCP_KEEPCNT:
2345 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2346 break;
2347 case TCP_SYNCNT:
2348 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2349 break;
2350 case TCP_LINGER2:
2351 val = tp->linger2;
2352 if (val >= 0)
2353 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2354 break;
2355 case TCP_DEFER_ACCEPT:
2356 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2357 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2358 break;
2359 case TCP_WINDOW_CLAMP:
2360 val = tp->window_clamp;
2361 break;
2362 case TCP_INFO: {
2363 struct tcp_info info;
2364
2365 if (get_user(len, optlen))
2366 return -EFAULT;
2367
2368 tcp_get_info(sk, &info);
2369
2370 len = min_t(unsigned int, len, sizeof(info));
2371 if (put_user(len, optlen))
2372 return -EFAULT;
2373 if (copy_to_user(optval, &info, len))
2374 return -EFAULT;
2375 return 0;
2376 }
2377 case TCP_QUICKACK:
2378 val = !icsk->icsk_ack.pingpong;
2379 break;
2380
2381 case TCP_CONGESTION:
2382 if (get_user(len, optlen))
2383 return -EFAULT;
2384 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2385 if (put_user(len, optlen))
2386 return -EFAULT;
2387 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2388 return -EFAULT;
2389 return 0;
2390 default:
2391 return -ENOPROTOOPT;
2392 }
2393
2394 if (put_user(len, optlen))
2395 return -EFAULT;
2396 if (copy_to_user(optval, &val, len))
2397 return -EFAULT;
2398 return 0;
2399 }
2400
2401 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2402 int __user *optlen)
2403 {
2404 struct inet_connection_sock *icsk = inet_csk(sk);
2405
2406 if (level != SOL_TCP)
2407 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2408 optval, optlen);
2409 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2410 }
2411
2412 #ifdef CONFIG_COMPAT
2413 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2414 char __user *optval, int __user *optlen)
2415 {
2416 if (level != SOL_TCP)
2417 return inet_csk_compat_getsockopt(sk, level, optname,
2418 optval, optlen);
2419 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2420 }
2421
2422 EXPORT_SYMBOL(compat_tcp_getsockopt);
2423 #endif
2424
2425 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2426 {
2427 struct sk_buff *segs = ERR_PTR(-EINVAL);
2428 struct tcphdr *th;
2429 unsigned thlen;
2430 unsigned int seq;
2431 __be32 delta;
2432 unsigned int oldlen;
2433 unsigned int mss;
2434
2435 if (!pskb_may_pull(skb, sizeof(*th)))
2436 goto out;
2437
2438 th = tcp_hdr(skb);
2439 thlen = th->doff * 4;
2440 if (thlen < sizeof(*th))
2441 goto out;
2442
2443 if (!pskb_may_pull(skb, thlen))
2444 goto out;
2445
2446 oldlen = (u16)~skb->len;
2447 __skb_pull(skb, thlen);
2448
2449 mss = skb_shinfo(skb)->gso_size;
2450 if (unlikely(skb->len <= mss))
2451 goto out;
2452
2453 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2454 /* Packet is from an untrusted source, reset gso_segs. */
2455 int type = skb_shinfo(skb)->gso_type;
2456
2457 if (unlikely(type &
2458 ~(SKB_GSO_TCPV4 |
2459 SKB_GSO_DODGY |
2460 SKB_GSO_TCP_ECN |
2461 SKB_GSO_TCPV6 |
2462 0) ||
2463 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2464 goto out;
2465
2466 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2467
2468 segs = NULL;
2469 goto out;
2470 }
2471
2472 segs = skb_segment(skb, features);
2473 if (IS_ERR(segs))
2474 goto out;
2475
2476 delta = htonl(oldlen + (thlen + mss));
2477
2478 skb = segs;
2479 th = tcp_hdr(skb);
2480 seq = ntohl(th->seq);
2481
2482 do {
2483 th->fin = th->psh = 0;
2484
2485 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2486 (__force u32)delta));
2487 if (skb->ip_summed != CHECKSUM_PARTIAL)
2488 th->check =
2489 csum_fold(csum_partial(skb_transport_header(skb),
2490 thlen, skb->csum));
2491
2492 seq += mss;
2493 skb = skb->next;
2494 th = tcp_hdr(skb);
2495
2496 th->seq = htonl(seq);
2497 th->cwr = 0;
2498 } while (skb->next);
2499
2500 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2501 skb->data_len);
2502 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2503 (__force u32)delta));
2504 if (skb->ip_summed != CHECKSUM_PARTIAL)
2505 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2506 thlen, skb->csum));
2507
2508 out:
2509 return segs;
2510 }
2511 EXPORT_SYMBOL(tcp_tso_segment);
2512
2513 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2514 {
2515 struct sk_buff **pp = NULL;
2516 struct sk_buff *p;
2517 struct tcphdr *th;
2518 struct tcphdr *th2;
2519 unsigned int len;
2520 unsigned int thlen;
2521 unsigned int flags;
2522 unsigned int mss = 1;
2523 unsigned int hlen;
2524 unsigned int off;
2525 int flush = 1;
2526 int i;
2527
2528 off = skb_gro_offset(skb);
2529 hlen = off + sizeof(*th);
2530 th = skb_gro_header_fast(skb, off);
2531 if (skb_gro_header_hard(skb, hlen)) {
2532 th = skb_gro_header_slow(skb, hlen, off);
2533 if (unlikely(!th))
2534 goto out;
2535 }
2536
2537 thlen = th->doff * 4;
2538 if (thlen < sizeof(*th))
2539 goto out;
2540
2541 hlen = off + thlen;
2542 if (skb_gro_header_hard(skb, hlen)) {
2543 th = skb_gro_header_slow(skb, hlen, off);
2544 if (unlikely(!th))
2545 goto out;
2546 }
2547
2548 skb_gro_pull(skb, thlen);
2549
2550 len = skb_gro_len(skb);
2551 flags = tcp_flag_word(th);
2552
2553 for (; (p = *head); head = &p->next) {
2554 if (!NAPI_GRO_CB(p)->same_flow)
2555 continue;
2556
2557 th2 = tcp_hdr(p);
2558
2559 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2560 NAPI_GRO_CB(p)->same_flow = 0;
2561 continue;
2562 }
2563
2564 goto found;
2565 }
2566
2567 goto out_check_final;
2568
2569 found:
2570 flush = NAPI_GRO_CB(p)->flush;
2571 flush |= flags & TCP_FLAG_CWR;
2572 flush |= (flags ^ tcp_flag_word(th2)) &
2573 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH);
2574 flush |= th->ack_seq ^ th2->ack_seq;
2575 for (i = sizeof(*th); i < thlen; i += 4)
2576 flush |= *(u32 *)((u8 *)th + i) ^
2577 *(u32 *)((u8 *)th2 + i);
2578
2579 mss = skb_shinfo(p)->gso_size;
2580
2581 flush |= (len - 1) >= mss;
2582 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2583
2584 if (flush || skb_gro_receive(head, skb)) {
2585 mss = 1;
2586 goto out_check_final;
2587 }
2588
2589 p = *head;
2590 th2 = tcp_hdr(p);
2591 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2592
2593 out_check_final:
2594 flush = len < mss;
2595 flush |= flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST |
2596 TCP_FLAG_SYN | TCP_FLAG_FIN);
2597
2598 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2599 pp = head;
2600
2601 out:
2602 NAPI_GRO_CB(skb)->flush |= flush;
2603
2604 return pp;
2605 }
2606 EXPORT_SYMBOL(tcp_gro_receive);
2607
2608 int tcp_gro_complete(struct sk_buff *skb)
2609 {
2610 struct tcphdr *th = tcp_hdr(skb);
2611
2612 skb->csum_start = skb_transport_header(skb) - skb->head;
2613 skb->csum_offset = offsetof(struct tcphdr, check);
2614 skb->ip_summed = CHECKSUM_PARTIAL;
2615
2616 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2617
2618 if (th->cwr)
2619 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2620
2621 return 0;
2622 }
2623 EXPORT_SYMBOL(tcp_gro_complete);
2624
2625 #ifdef CONFIG_TCP_MD5SIG
2626 static unsigned long tcp_md5sig_users;
2627 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2628 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2629
2630 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2631 {
2632 int cpu;
2633 for_each_possible_cpu(cpu) {
2634 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2635 if (p) {
2636 if (p->md5_desc.tfm)
2637 crypto_free_hash(p->md5_desc.tfm);
2638 kfree(p);
2639 p = NULL;
2640 }
2641 }
2642 free_percpu(pool);
2643 }
2644
2645 void tcp_free_md5sig_pool(void)
2646 {
2647 struct tcp_md5sig_pool **pool = NULL;
2648
2649 spin_lock_bh(&tcp_md5sig_pool_lock);
2650 if (--tcp_md5sig_users == 0) {
2651 pool = tcp_md5sig_pool;
2652 tcp_md5sig_pool = NULL;
2653 }
2654 spin_unlock_bh(&tcp_md5sig_pool_lock);
2655 if (pool)
2656 __tcp_free_md5sig_pool(pool);
2657 }
2658
2659 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2660
2661 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
2662 {
2663 int cpu;
2664 struct tcp_md5sig_pool **pool;
2665
2666 pool = alloc_percpu(struct tcp_md5sig_pool *);
2667 if (!pool)
2668 return NULL;
2669
2670 for_each_possible_cpu(cpu) {
2671 struct tcp_md5sig_pool *p;
2672 struct crypto_hash *hash;
2673
2674 p = kzalloc(sizeof(*p), GFP_KERNEL);
2675 if (!p)
2676 goto out_free;
2677 *per_cpu_ptr(pool, cpu) = p;
2678
2679 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2680 if (!hash || IS_ERR(hash))
2681 goto out_free;
2682
2683 p->md5_desc.tfm = hash;
2684 }
2685 return pool;
2686 out_free:
2687 __tcp_free_md5sig_pool(pool);
2688 return NULL;
2689 }
2690
2691 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
2692 {
2693 struct tcp_md5sig_pool **pool;
2694 int alloc = 0;
2695
2696 retry:
2697 spin_lock_bh(&tcp_md5sig_pool_lock);
2698 pool = tcp_md5sig_pool;
2699 if (tcp_md5sig_users++ == 0) {
2700 alloc = 1;
2701 spin_unlock_bh(&tcp_md5sig_pool_lock);
2702 } else if (!pool) {
2703 tcp_md5sig_users--;
2704 spin_unlock_bh(&tcp_md5sig_pool_lock);
2705 cpu_relax();
2706 goto retry;
2707 } else
2708 spin_unlock_bh(&tcp_md5sig_pool_lock);
2709
2710 if (alloc) {
2711 /* we cannot hold spinlock here because this may sleep. */
2712 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
2713 spin_lock_bh(&tcp_md5sig_pool_lock);
2714 if (!p) {
2715 tcp_md5sig_users--;
2716 spin_unlock_bh(&tcp_md5sig_pool_lock);
2717 return NULL;
2718 }
2719 pool = tcp_md5sig_pool;
2720 if (pool) {
2721 /* oops, it has already been assigned. */
2722 spin_unlock_bh(&tcp_md5sig_pool_lock);
2723 __tcp_free_md5sig_pool(p);
2724 } else {
2725 tcp_md5sig_pool = pool = p;
2726 spin_unlock_bh(&tcp_md5sig_pool_lock);
2727 }
2728 }
2729 return pool;
2730 }
2731
2732 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2733
2734 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2735 {
2736 struct tcp_md5sig_pool **p;
2737 spin_lock_bh(&tcp_md5sig_pool_lock);
2738 p = tcp_md5sig_pool;
2739 if (p)
2740 tcp_md5sig_users++;
2741 spin_unlock_bh(&tcp_md5sig_pool_lock);
2742 return (p ? *per_cpu_ptr(p, cpu) : NULL);
2743 }
2744
2745 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2746
2747 void __tcp_put_md5sig_pool(void)
2748 {
2749 tcp_free_md5sig_pool();
2750 }
2751
2752 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2753
2754 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2755 struct tcphdr *th)
2756 {
2757 struct scatterlist sg;
2758 int err;
2759
2760 __sum16 old_checksum = th->check;
2761 th->check = 0;
2762 /* options aren't included in the hash */
2763 sg_init_one(&sg, th, sizeof(struct tcphdr));
2764 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
2765 th->check = old_checksum;
2766 return err;
2767 }
2768
2769 EXPORT_SYMBOL(tcp_md5_hash_header);
2770
2771 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2772 struct sk_buff *skb, unsigned header_len)
2773 {
2774 struct scatterlist sg;
2775 const struct tcphdr *tp = tcp_hdr(skb);
2776 struct hash_desc *desc = &hp->md5_desc;
2777 unsigned i;
2778 const unsigned head_data_len = skb_headlen(skb) > header_len ?
2779 skb_headlen(skb) - header_len : 0;
2780 const struct skb_shared_info *shi = skb_shinfo(skb);
2781
2782 sg_init_table(&sg, 1);
2783
2784 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2785 if (crypto_hash_update(desc, &sg, head_data_len))
2786 return 1;
2787
2788 for (i = 0; i < shi->nr_frags; ++i) {
2789 const struct skb_frag_struct *f = &shi->frags[i];
2790 sg_set_page(&sg, f->page, f->size, f->page_offset);
2791 if (crypto_hash_update(desc, &sg, f->size))
2792 return 1;
2793 }
2794
2795 return 0;
2796 }
2797
2798 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
2799
2800 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
2801 {
2802 struct scatterlist sg;
2803
2804 sg_init_one(&sg, key->key, key->keylen);
2805 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
2806 }
2807
2808 EXPORT_SYMBOL(tcp_md5_hash_key);
2809
2810 #endif
2811
2812 void tcp_done(struct sock *sk)
2813 {
2814 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2815 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
2816
2817 tcp_set_state(sk, TCP_CLOSE);
2818 tcp_clear_xmit_timers(sk);
2819
2820 sk->sk_shutdown = SHUTDOWN_MASK;
2821
2822 if (!sock_flag(sk, SOCK_DEAD))
2823 sk->sk_state_change(sk);
2824 else
2825 inet_csk_destroy_sock(sk);
2826 }
2827 EXPORT_SYMBOL_GPL(tcp_done);
2828
2829 extern struct tcp_congestion_ops tcp_reno;
2830
2831 static __initdata unsigned long thash_entries;
2832 static int __init set_thash_entries(char *str)
2833 {
2834 if (!str)
2835 return 0;
2836 thash_entries = simple_strtoul(str, &str, 0);
2837 return 1;
2838 }
2839 __setup("thash_entries=", set_thash_entries);
2840
2841 void __init tcp_init(void)
2842 {
2843 struct sk_buff *skb = NULL;
2844 unsigned long nr_pages, limit;
2845 int order, i, max_share;
2846
2847 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
2848
2849 percpu_counter_init(&tcp_sockets_allocated, 0);
2850 percpu_counter_init(&tcp_orphan_count, 0);
2851 tcp_hashinfo.bind_bucket_cachep =
2852 kmem_cache_create("tcp_bind_bucket",
2853 sizeof(struct inet_bind_bucket), 0,
2854 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2855
2856 /* Size and allocate the main established and bind bucket
2857 * hash tables.
2858 *
2859 * The methodology is similar to that of the buffer cache.
2860 */
2861 tcp_hashinfo.ehash =
2862 alloc_large_system_hash("TCP established",
2863 sizeof(struct inet_ehash_bucket),
2864 thash_entries,
2865 (num_physpages >= 128 * 1024) ?
2866 13 : 15,
2867 0,
2868 &tcp_hashinfo.ehash_size,
2869 NULL,
2870 thash_entries ? 0 : 512 * 1024);
2871 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2872 for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2873 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
2874 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
2875 }
2876 if (inet_ehash_locks_alloc(&tcp_hashinfo))
2877 panic("TCP: failed to alloc ehash_locks");
2878 tcp_hashinfo.bhash =
2879 alloc_large_system_hash("TCP bind",
2880 sizeof(struct inet_bind_hashbucket),
2881 tcp_hashinfo.ehash_size,
2882 (num_physpages >= 128 * 1024) ?
2883 13 : 15,
2884 0,
2885 &tcp_hashinfo.bhash_size,
2886 NULL,
2887 64 * 1024);
2888 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2889 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2890 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2891 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2892 }
2893
2894 /* Try to be a bit smarter and adjust defaults depending
2895 * on available memory.
2896 */
2897 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2898 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2899 order++)
2900 ;
2901 if (order >= 4) {
2902 tcp_death_row.sysctl_max_tw_buckets = 180000;
2903 sysctl_tcp_max_orphans = 4096 << (order - 4);
2904 sysctl_max_syn_backlog = 1024;
2905 } else if (order < 3) {
2906 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2907 sysctl_tcp_max_orphans >>= (3 - order);
2908 sysctl_max_syn_backlog = 128;
2909 }
2910
2911 /* Set the pressure threshold to be a fraction of global memory that
2912 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2913 * memory, with a floor of 128 pages.
2914 */
2915 nr_pages = totalram_pages - totalhigh_pages;
2916 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
2917 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
2918 limit = max(limit, 128UL);
2919 sysctl_tcp_mem[0] = limit / 4 * 3;
2920 sysctl_tcp_mem[1] = limit;
2921 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
2922
2923 /* Set per-socket limits to no more than 1/128 the pressure threshold */
2924 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2925 max_share = min(4UL*1024*1024, limit);
2926
2927 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
2928 sysctl_tcp_wmem[1] = 16*1024;
2929 sysctl_tcp_wmem[2] = max(64*1024, max_share);
2930
2931 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
2932 sysctl_tcp_rmem[1] = 87380;
2933 sysctl_tcp_rmem[2] = max(87380, max_share);
2934
2935 printk(KERN_INFO "TCP: Hash tables configured "
2936 "(established %d bind %d)\n",
2937 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
2938
2939 tcp_register_congestion_control(&tcp_reno);
2940 }
2941
2942 EXPORT_SYMBOL(tcp_close);
2943 EXPORT_SYMBOL(tcp_disconnect);
2944 EXPORT_SYMBOL(tcp_getsockopt);
2945 EXPORT_SYMBOL(tcp_ioctl);
2946 EXPORT_SYMBOL(tcp_poll);
2947 EXPORT_SYMBOL(tcp_read_sock);
2948 EXPORT_SYMBOL(tcp_recvmsg);
2949 EXPORT_SYMBOL(tcp_sendmsg);
2950 EXPORT_SYMBOL(tcp_splice_read);
2951 EXPORT_SYMBOL(tcp_sendpage);
2952 EXPORT_SYMBOL(tcp_setsockopt);
2953 EXPORT_SYMBOL(tcp_shutdown);
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