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Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[linux-2.6/mini2440.git] / net / ipv4 / tcp.c
blob7a0f0b27bf1f0affc18e57c96b7c002aa5376fcc
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 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 answ = tp->rcv_nxt - tp->copied_seq;
443
444 /* Subtract 1, if FIN is in queue. */
445 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
446 answ -=
447 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin;
448 } else
449 answ = tp->urg_seq - tp->copied_seq;
450 release_sock(sk);
451 break;
452 case SIOCATMARK:
453 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
454 break;
455 case SIOCOUTQ:
456 if (sk->sk_state == TCP_LISTEN)
457 return -EINVAL;
458
459 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
460 answ = 0;
461 else
462 answ = tp->write_seq - tp->snd_una;
463 break;
464 default:
465 return -ENOIOCTLCMD;
466 }
467
468 return put_user(answ, (int __user *)arg);
469 }
470
471 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
472 {
473 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
474 tp->pushed_seq = tp->write_seq;
475 }
476
477 static inline int forced_push(struct tcp_sock *tp)
478 {
479 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
480 }
481
482 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
483 {
484 struct tcp_sock *tp = tcp_sk(sk);
485 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
486
487 skb->csum = 0;
488 tcb->seq = tcb->end_seq = tp->write_seq;
489 tcb->flags = TCPCB_FLAG_ACK;
490 tcb->sacked = 0;
491 skb_header_release(skb);
492 tcp_add_write_queue_tail(sk, skb);
493 sk->sk_wmem_queued += skb->truesize;
494 sk_mem_charge(sk, skb->truesize);
495 if (tp->nonagle & TCP_NAGLE_PUSH)
496 tp->nonagle &= ~TCP_NAGLE_PUSH;
497 }
498
499 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
500 struct sk_buff *skb)
501 {
502 if (flags & MSG_OOB)
503 tp->snd_up = tp->write_seq;
504 }
505
506 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
507 int nonagle)
508 {
509 struct tcp_sock *tp = tcp_sk(sk);
510
511 if (tcp_send_head(sk)) {
512 struct sk_buff *skb = tcp_write_queue_tail(sk);
513 if (!(flags & MSG_MORE) || forced_push(tp))
514 tcp_mark_push(tp, skb);
515 tcp_mark_urg(tp, flags, skb);
516 __tcp_push_pending_frames(sk, mss_now,
517 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
518 }
519 }
520
521 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
522 unsigned int offset, size_t len)
523 {
524 struct tcp_splice_state *tss = rd_desc->arg.data;
525 int ret;
526
527 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
528 tss->flags);
529 if (ret > 0)
530 rd_desc->count -= ret;
531 return ret;
532 }
533
534 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
535 {
536 /* Store TCP splice context information in read_descriptor_t. */
537 read_descriptor_t rd_desc = {
538 .arg.data = tss,
539 .count = tss->len,
540 };
541
542 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
543 }
544
545 /**
546 * tcp_splice_read - splice data from TCP socket to a pipe
547 * @sock: socket to splice from
548 * @ppos: position (not valid)
549 * @pipe: pipe to splice to
550 * @len: number of bytes to splice
551 * @flags: splice modifier flags
552 *
553 * Description:
554 * Will read pages from given socket and fill them into a pipe.
555 *
556 **/
557 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
558 struct pipe_inode_info *pipe, size_t len,
559 unsigned int flags)
560 {
561 struct sock *sk = sock->sk;
562 struct tcp_splice_state tss = {
563 .pipe = pipe,
564 .len = len,
565 .flags = flags,
566 };
567 long timeo;
568 ssize_t spliced;
569 int ret;
570
571 /*
572 * We can't seek on a socket input
573 */
574 if (unlikely(*ppos))
575 return -ESPIPE;
576
577 ret = spliced = 0;
578
579 lock_sock(sk);
580
581 timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK);
582 while (tss.len) {
583 ret = __tcp_splice_read(sk, &tss);
584 if (ret < 0)
585 break;
586 else if (!ret) {
587 if (spliced)
588 break;
589 if (sock_flag(sk, SOCK_DONE))
590 break;
591 if (sk->sk_err) {
592 ret = sock_error(sk);
593 break;
594 }
595 if (sk->sk_shutdown & RCV_SHUTDOWN)
596 break;
597 if (sk->sk_state == TCP_CLOSE) {
598 /*
599 * This occurs when user tries to read
600 * from never connected socket.
601 */
602 if (!sock_flag(sk, SOCK_DONE))
603 ret = -ENOTCONN;
604 break;
605 }
606 if (!timeo) {
607 ret = -EAGAIN;
608 break;
609 }
610 sk_wait_data(sk, &timeo);
611 if (signal_pending(current)) {
612 ret = sock_intr_errno(timeo);
613 break;
614 }
615 continue;
616 }
617 tss.len -= ret;
618 spliced += ret;
619
620 if (!timeo)
621 break;
622 release_sock(sk);
623 lock_sock(sk);
624
625 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
626 (sk->sk_shutdown & RCV_SHUTDOWN) ||
627 signal_pending(current))
628 break;
629 }
630
631 release_sock(sk);
632
633 if (spliced)
634 return spliced;
635
636 return ret;
637 }
638
639 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
640 {
641 struct sk_buff *skb;
642
643 /* The TCP header must be at least 32-bit aligned. */
644 size = ALIGN(size, 4);
645
646 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
647 if (skb) {
648 if (sk_wmem_schedule(sk, skb->truesize)) {
649 /*
650 * Make sure that we have exactly size bytes
651 * available to the caller, no more, no less.
652 */
653 skb_reserve(skb, skb_tailroom(skb) - size);
654 return skb;
655 }
656 __kfree_skb(skb);
657 } else {
658 sk->sk_prot->enter_memory_pressure(sk);
659 sk_stream_moderate_sndbuf(sk);
660 }
661 return NULL;
662 }
663
664 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
665 int large_allowed)
666 {
667 struct tcp_sock *tp = tcp_sk(sk);
668 u32 xmit_size_goal, old_size_goal;
669
670 xmit_size_goal = mss_now;
671
672 if (large_allowed && sk_can_gso(sk)) {
673 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
674 inet_csk(sk)->icsk_af_ops->net_header_len -
675 inet_csk(sk)->icsk_ext_hdr_len -
676 tp->tcp_header_len);
677
678 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
679
680 /* We try hard to avoid divides here */
681 old_size_goal = tp->xmit_size_goal_segs * mss_now;
682
683 if (likely(old_size_goal <= xmit_size_goal &&
684 old_size_goal + mss_now > xmit_size_goal)) {
685 xmit_size_goal = old_size_goal;
686 } else {
687 tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
688 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
689 }
690 }
691
692 return max(xmit_size_goal, mss_now);
693 }
694
695 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
696 {
697 int mss_now;
698
699 mss_now = tcp_current_mss(sk);
700 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
701
702 return mss_now;
703 }
704
705 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
706 size_t psize, int flags)
707 {
708 struct tcp_sock *tp = tcp_sk(sk);
709 int mss_now, size_goal;
710 int err;
711 ssize_t copied;
712 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
713
714 /* Wait for a connection to finish. */
715 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
716 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
717 goto out_err;
718
719 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
720
721 mss_now = tcp_send_mss(sk, &size_goal, flags);
722 copied = 0;
723
724 err = -EPIPE;
725 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
726 goto out_err;
727
728 while (psize > 0) {
729 struct sk_buff *skb = tcp_write_queue_tail(sk);
730 struct page *page = pages[poffset / PAGE_SIZE];
731 int copy, i, can_coalesce;
732 int offset = poffset % PAGE_SIZE;
733 int size = min_t(size_t, psize, PAGE_SIZE - offset);
734
735 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
736 new_segment:
737 if (!sk_stream_memory_free(sk))
738 goto wait_for_sndbuf;
739
740 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
741 if (!skb)
742 goto wait_for_memory;
743
744 skb_entail(sk, skb);
745 copy = size_goal;
746 }
747
748 if (copy > size)
749 copy = size;
750
751 i = skb_shinfo(skb)->nr_frags;
752 can_coalesce = skb_can_coalesce(skb, i, page, offset);
753 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
754 tcp_mark_push(tp, skb);
755 goto new_segment;
756 }
757 if (!sk_wmem_schedule(sk, copy))
758 goto wait_for_memory;
759
760 if (can_coalesce) {
761 skb_shinfo(skb)->frags[i - 1].size += copy;
762 } else {
763 get_page(page);
764 skb_fill_page_desc(skb, i, page, offset, copy);
765 }
766
767 skb->len += copy;
768 skb->data_len += copy;
769 skb->truesize += copy;
770 sk->sk_wmem_queued += copy;
771 sk_mem_charge(sk, copy);
772 skb->ip_summed = CHECKSUM_PARTIAL;
773 tp->write_seq += copy;
774 TCP_SKB_CB(skb)->end_seq += copy;
775 skb_shinfo(skb)->gso_segs = 0;
776
777 if (!copied)
778 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
779
780 copied += copy;
781 poffset += copy;
782 if (!(psize -= copy))
783 goto out;
784
785 if (skb->len < size_goal || (flags & MSG_OOB))
786 continue;
787
788 if (forced_push(tp)) {
789 tcp_mark_push(tp, skb);
790 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
791 } else if (skb == tcp_send_head(sk))
792 tcp_push_one(sk, mss_now);
793 continue;
794
795 wait_for_sndbuf:
796 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
797 wait_for_memory:
798 if (copied)
799 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
800
801 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
802 goto do_error;
803
804 mss_now = tcp_send_mss(sk, &size_goal, flags);
805 }
806
807 out:
808 if (copied)
809 tcp_push(sk, flags, mss_now, tp->nonagle);
810 return copied;
811
812 do_error:
813 if (copied)
814 goto out;
815 out_err:
816 return sk_stream_error(sk, flags, err);
817 }
818
819 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
820 size_t size, int flags)
821 {
822 ssize_t res;
823 struct sock *sk = sock->sk;
824
825 if (!(sk->sk_route_caps & NETIF_F_SG) ||
826 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
827 return sock_no_sendpage(sock, page, offset, size, flags);
828
829 lock_sock(sk);
830 TCP_CHECK_TIMER(sk);
831 res = do_tcp_sendpages(sk, &page, offset, size, flags);
832 TCP_CHECK_TIMER(sk);
833 release_sock(sk);
834 return res;
835 }
836
837 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
838 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
839
840 static inline int select_size(struct sock *sk)
841 {
842 struct tcp_sock *tp = tcp_sk(sk);
843 int tmp = tp->mss_cache;
844
845 if (sk->sk_route_caps & NETIF_F_SG) {
846 if (sk_can_gso(sk))
847 tmp = 0;
848 else {
849 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
850
851 if (tmp >= pgbreak &&
852 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
853 tmp = pgbreak;
854 }
855 }
856
857 return tmp;
858 }
859
860 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
861 size_t size)
862 {
863 struct sock *sk = sock->sk;
864 struct iovec *iov;
865 struct tcp_sock *tp = tcp_sk(sk);
866 struct sk_buff *skb;
867 int iovlen, flags;
868 int mss_now, size_goal;
869 int err, copied;
870 long timeo;
871
872 lock_sock(sk);
873 TCP_CHECK_TIMER(sk);
874
875 flags = msg->msg_flags;
876 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
877
878 /* Wait for a connection to finish. */
879 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
880 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
881 goto out_err;
882
883 /* This should be in poll */
884 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
885
886 mss_now = tcp_send_mss(sk, &size_goal, flags);
887
888 /* Ok commence sending. */
889 iovlen = msg->msg_iovlen;
890 iov = msg->msg_iov;
891 copied = 0;
892
893 err = -EPIPE;
894 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
895 goto out_err;
896
897 while (--iovlen >= 0) {
898 int seglen = iov->iov_len;
899 unsigned char __user *from = iov->iov_base;
900
901 iov++;
902
903 while (seglen > 0) {
904 int copy;
905
906 skb = tcp_write_queue_tail(sk);
907
908 if (!tcp_send_head(sk) ||
909 (copy = size_goal - skb->len) <= 0) {
910
911 new_segment:
912 /* Allocate new segment. If the interface is SG,
913 * allocate skb fitting to single page.
914 */
915 if (!sk_stream_memory_free(sk))
916 goto wait_for_sndbuf;
917
918 skb = sk_stream_alloc_skb(sk, select_size(sk),
919 sk->sk_allocation);
920 if (!skb)
921 goto wait_for_memory;
922
923 /*
924 * Check whether we can use HW checksum.
925 */
926 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
927 skb->ip_summed = CHECKSUM_PARTIAL;
928
929 skb_entail(sk, skb);
930 copy = size_goal;
931 }
932
933 /* Try to append data to the end of skb. */
934 if (copy > seglen)
935 copy = seglen;
936
937 /* Where to copy to? */
938 if (skb_tailroom(skb) > 0) {
939 /* We have some space in skb head. Superb! */
940 if (copy > skb_tailroom(skb))
941 copy = skb_tailroom(skb);
942 if ((err = skb_add_data(skb, from, copy)) != 0)
943 goto do_fault;
944 } else {
945 int merge = 0;
946 int i = skb_shinfo(skb)->nr_frags;
947 struct page *page = TCP_PAGE(sk);
948 int off = TCP_OFF(sk);
949
950 if (skb_can_coalesce(skb, i, page, off) &&
951 off != PAGE_SIZE) {
952 /* We can extend the last page
953 * fragment. */
954 merge = 1;
955 } else if (i == MAX_SKB_FRAGS ||
956 (!i &&
957 !(sk->sk_route_caps & NETIF_F_SG))) {
958 /* Need to add new fragment and cannot
959 * do this because interface is non-SG,
960 * or because all the page slots are
961 * busy. */
962 tcp_mark_push(tp, skb);
963 goto new_segment;
964 } else if (page) {
965 if (off == PAGE_SIZE) {
966 put_page(page);
967 TCP_PAGE(sk) = page = NULL;
968 off = 0;
969 }
970 } else
971 off = 0;
972
973 if (copy > PAGE_SIZE - off)
974 copy = PAGE_SIZE - off;
975
976 if (!sk_wmem_schedule(sk, copy))
977 goto wait_for_memory;
978
979 if (!page) {
980 /* Allocate new cache page. */
981 if (!(page = sk_stream_alloc_page(sk)))
982 goto wait_for_memory;
983 }
984
985 /* Time to copy data. We are close to
986 * the end! */
987 err = skb_copy_to_page(sk, from, skb, page,
988 off, copy);
989 if (err) {
990 /* If this page was new, give it to the
991 * socket so it does not get leaked.
992 */
993 if (!TCP_PAGE(sk)) {
994 TCP_PAGE(sk) = page;
995 TCP_OFF(sk) = 0;
996 }
997 goto do_error;
998 }
999
1000 /* Update the skb. */
1001 if (merge) {
1002 skb_shinfo(skb)->frags[i - 1].size +=
1003 copy;
1004 } else {
1005 skb_fill_page_desc(skb, i, page, off, copy);
1006 if (TCP_PAGE(sk)) {
1007 get_page(page);
1008 } else if (off + copy < PAGE_SIZE) {
1009 get_page(page);
1010 TCP_PAGE(sk) = page;
1011 }
1012 }
1013
1014 TCP_OFF(sk) = off + copy;
1015 }
1016
1017 if (!copied)
1018 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
1019
1020 tp->write_seq += copy;
1021 TCP_SKB_CB(skb)->end_seq += copy;
1022 skb_shinfo(skb)->gso_segs = 0;
1023
1024 from += copy;
1025 copied += copy;
1026 if ((seglen -= copy) == 0 && iovlen == 0)
1027 goto out;
1028
1029 if (skb->len < size_goal || (flags & MSG_OOB))
1030 continue;
1031
1032 if (forced_push(tp)) {
1033 tcp_mark_push(tp, skb);
1034 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1035 } else if (skb == tcp_send_head(sk))
1036 tcp_push_one(sk, mss_now);
1037 continue;
1038
1039 wait_for_sndbuf:
1040 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1041 wait_for_memory:
1042 if (copied)
1043 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1044
1045 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1046 goto do_error;
1047
1048 mss_now = tcp_send_mss(sk, &size_goal, flags);
1049 }
1050 }
1051
1052 out:
1053 if (copied)
1054 tcp_push(sk, flags, mss_now, tp->nonagle);
1055 TCP_CHECK_TIMER(sk);
1056 release_sock(sk);
1057 return copied;
1058
1059 do_fault:
1060 if (!skb->len) {
1061 tcp_unlink_write_queue(skb, sk);
1062 /* It is the one place in all of TCP, except connection
1063 * reset, where we can be unlinking the send_head.
1064 */
1065 tcp_check_send_head(sk, skb);
1066 sk_wmem_free_skb(sk, skb);
1067 }
1068
1069 do_error:
1070 if (copied)
1071 goto out;
1072 out_err:
1073 err = sk_stream_error(sk, flags, err);
1074 TCP_CHECK_TIMER(sk);
1075 release_sock(sk);
1076 return err;
1077 }
1078
1079 /*
1080 * Handle reading urgent data. BSD has very simple semantics for
1081 * this, no blocking and very strange errors 8)
1082 */
1083
1084 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1085 {
1086 struct tcp_sock *tp = tcp_sk(sk);
1087
1088 /* No URG data to read. */
1089 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1090 tp->urg_data == TCP_URG_READ)
1091 return -EINVAL; /* Yes this is right ! */
1092
1093 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1094 return -ENOTCONN;
1095
1096 if (tp->urg_data & TCP_URG_VALID) {
1097 int err = 0;
1098 char c = tp->urg_data;
1099
1100 if (!(flags & MSG_PEEK))
1101 tp->urg_data = TCP_URG_READ;
1102
1103 /* Read urgent data. */
1104 msg->msg_flags |= MSG_OOB;
1105
1106 if (len > 0) {
1107 if (!(flags & MSG_TRUNC))
1108 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1109 len = 1;
1110 } else
1111 msg->msg_flags |= MSG_TRUNC;
1112
1113 return err ? -EFAULT : len;
1114 }
1115
1116 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1117 return 0;
1118
1119 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1120 * the available implementations agree in this case:
1121 * this call should never block, independent of the
1122 * blocking state of the socket.
1123 * Mike <pall@rz.uni-karlsruhe.de>
1124 */
1125 return -EAGAIN;
1126 }
1127
1128 /* Clean up the receive buffer for full frames taken by the user,
1129 * then send an ACK if necessary. COPIED is the number of bytes
1130 * tcp_recvmsg has given to the user so far, it speeds up the
1131 * calculation of whether or not we must ACK for the sake of
1132 * a window update.
1133 */
1134 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1135 {
1136 struct tcp_sock *tp = tcp_sk(sk);
1137 int time_to_ack = 0;
1138
1139 #if TCP_DEBUG
1140 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1141
1142 WARN_ON(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
1143 #endif
1144
1145 if (inet_csk_ack_scheduled(sk)) {
1146 const struct inet_connection_sock *icsk = inet_csk(sk);
1147 /* Delayed ACKs frequently hit locked sockets during bulk
1148 * receive. */
1149 if (icsk->icsk_ack.blocked ||
1150 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1151 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1152 /*
1153 * If this read emptied read buffer, we send ACK, if
1154 * connection is not bidirectional, user drained
1155 * receive buffer and there was a small segment
1156 * in queue.
1157 */
1158 (copied > 0 &&
1159 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1160 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1161 !icsk->icsk_ack.pingpong)) &&
1162 !atomic_read(&sk->sk_rmem_alloc)))
1163 time_to_ack = 1;
1164 }
1165
1166 /* We send an ACK if we can now advertise a non-zero window
1167 * which has been raised "significantly".
1168 *
1169 * Even if window raised up to infinity, do not send window open ACK
1170 * in states, where we will not receive more. It is useless.
1171 */
1172 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1173 __u32 rcv_window_now = tcp_receive_window(tp);
1174
1175 /* Optimize, __tcp_select_window() is not cheap. */
1176 if (2*rcv_window_now <= tp->window_clamp) {
1177 __u32 new_window = __tcp_select_window(sk);
1178
1179 /* Send ACK now, if this read freed lots of space
1180 * in our buffer. Certainly, new_window is new window.
1181 * We can advertise it now, if it is not less than current one.
1182 * "Lots" means "at least twice" here.
1183 */
1184 if (new_window && new_window >= 2 * rcv_window_now)
1185 time_to_ack = 1;
1186 }
1187 }
1188 if (time_to_ack)
1189 tcp_send_ack(sk);
1190 }
1191
1192 static void tcp_prequeue_process(struct sock *sk)
1193 {
1194 struct sk_buff *skb;
1195 struct tcp_sock *tp = tcp_sk(sk);
1196
1197 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1198
1199 /* RX process wants to run with disabled BHs, though it is not
1200 * necessary */
1201 local_bh_disable();
1202 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1203 sk_backlog_rcv(sk, skb);
1204 local_bh_enable();
1205
1206 /* Clear memory counter. */
1207 tp->ucopy.memory = 0;
1208 }
1209
1210 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1211 {
1212 struct sk_buff *skb;
1213 u32 offset;
1214
1215 skb_queue_walk(&sk->sk_receive_queue, skb) {
1216 offset = seq - TCP_SKB_CB(skb)->seq;
1217 if (tcp_hdr(skb)->syn)
1218 offset--;
1219 if (offset < skb->len || tcp_hdr(skb)->fin) {
1220 *off = offset;
1221 return skb;
1222 }
1223 }
1224 return NULL;
1225 }
1226
1227 /*
1228 * This routine provides an alternative to tcp_recvmsg() for routines
1229 * that would like to handle copying from skbuffs directly in 'sendfile'
1230 * fashion.
1231 * Note:
1232 * - It is assumed that the socket was locked by the caller.
1233 * - The routine does not block.
1234 * - At present, there is no support for reading OOB data
1235 * or for 'peeking' the socket using this routine
1236 * (although both would be easy to implement).
1237 */
1238 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1239 sk_read_actor_t recv_actor)
1240 {
1241 struct sk_buff *skb;
1242 struct tcp_sock *tp = tcp_sk(sk);
1243 u32 seq = tp->copied_seq;
1244 u32 offset;
1245 int copied = 0;
1246
1247 if (sk->sk_state == TCP_LISTEN)
1248 return -ENOTCONN;
1249 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1250 if (offset < skb->len) {
1251 int used;
1252 size_t len;
1253
1254 len = skb->len - offset;
1255 /* Stop reading if we hit a patch of urgent data */
1256 if (tp->urg_data) {
1257 u32 urg_offset = tp->urg_seq - seq;
1258 if (urg_offset < len)
1259 len = urg_offset;
1260 if (!len)
1261 break;
1262 }
1263 used = recv_actor(desc, skb, offset, len);
1264 if (used < 0) {
1265 if (!copied)
1266 copied = used;
1267 break;
1268 } else if (used <= len) {
1269 seq += used;
1270 copied += used;
1271 offset += used;
1272 }
1273 /*
1274 * If recv_actor drops the lock (e.g. TCP splice
1275 * receive) the skb pointer might be invalid when
1276 * getting here: tcp_collapse might have deleted it
1277 * while aggregating skbs from the socket queue.
1278 */
1279 skb = tcp_recv_skb(sk, seq-1, &offset);
1280 if (!skb || (offset+1 != skb->len))
1281 break;
1282 }
1283 if (tcp_hdr(skb)->fin) {
1284 sk_eat_skb(sk, skb, 0);
1285 ++seq;
1286 break;
1287 }
1288 sk_eat_skb(sk, skb, 0);
1289 if (!desc->count)
1290 break;
1291 }
1292 tp->copied_seq = seq;
1293
1294 tcp_rcv_space_adjust(sk);
1295
1296 /* Clean up data we have read: This will do ACK frames. */
1297 if (copied > 0)
1298 tcp_cleanup_rbuf(sk, copied);
1299 return copied;
1300 }
1301
1302 /*
1303 * This routine copies from a sock struct into the user buffer.
1304 *
1305 * Technical note: in 2.3 we work on _locked_ socket, so that
1306 * tricks with *seq access order and skb->users are not required.
1307 * Probably, code can be easily improved even more.
1308 */
1309
1310 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1311 size_t len, int nonblock, int flags, int *addr_len)
1312 {
1313 struct tcp_sock *tp = tcp_sk(sk);
1314 int copied = 0;
1315 u32 peek_seq;
1316 u32 *seq;
1317 unsigned long used;
1318 int err;
1319 int target; /* Read at least this many bytes */
1320 long timeo;
1321 struct task_struct *user_recv = NULL;
1322 int copied_early = 0;
1323 struct sk_buff *skb;
1324 u32 urg_hole = 0;
1325
1326 lock_sock(sk);
1327
1328 TCP_CHECK_TIMER(sk);
1329
1330 err = -ENOTCONN;
1331 if (sk->sk_state == TCP_LISTEN)
1332 goto out;
1333
1334 timeo = sock_rcvtimeo(sk, nonblock);
1335
1336 /* Urgent data needs to be handled specially. */
1337 if (flags & MSG_OOB)
1338 goto recv_urg;
1339
1340 seq = &tp->copied_seq;
1341 if (flags & MSG_PEEK) {
1342 peek_seq = tp->copied_seq;
1343 seq = &peek_seq;
1344 }
1345
1346 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1347
1348 #ifdef CONFIG_NET_DMA
1349 tp->ucopy.dma_chan = NULL;
1350 preempt_disable();
1351 skb = skb_peek_tail(&sk->sk_receive_queue);
1352 {
1353 int available = 0;
1354
1355 if (skb)
1356 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1357 if ((available < target) &&
1358 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1359 !sysctl_tcp_low_latency &&
1360 dma_find_channel(DMA_MEMCPY)) {
1361 preempt_enable_no_resched();
1362 tp->ucopy.pinned_list =
1363 dma_pin_iovec_pages(msg->msg_iov, len);
1364 } else {
1365 preempt_enable_no_resched();
1366 }
1367 }
1368 #endif
1369
1370 do {
1371 u32 offset;
1372
1373 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1374 if (tp->urg_data && tp->urg_seq == *seq) {
1375 if (copied)
1376 break;
1377 if (signal_pending(current)) {
1378 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1379 break;
1380 }
1381 }
1382
1383 /* Next get a buffer. */
1384
1385 skb = skb_peek(&sk->sk_receive_queue);
1386 do {
1387 if (!skb)
1388 break;
1389
1390 /* Now that we have two receive queues this
1391 * shouldn't happen.
1392 */
1393 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1394 printk(KERN_INFO "recvmsg bug: copied %X "
1395 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1396 break;
1397 }
1398 offset = *seq - TCP_SKB_CB(skb)->seq;
1399 if (tcp_hdr(skb)->syn)
1400 offset--;
1401 if (offset < skb->len)
1402 goto found_ok_skb;
1403 if (tcp_hdr(skb)->fin)
1404 goto found_fin_ok;
1405 WARN_ON(!(flags & MSG_PEEK));
1406 skb = skb->next;
1407 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1408
1409 /* Well, if we have backlog, try to process it now yet. */
1410
1411 if (copied >= target && !sk->sk_backlog.tail)
1412 break;
1413
1414 if (copied) {
1415 if (sk->sk_err ||
1416 sk->sk_state == TCP_CLOSE ||
1417 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1418 !timeo ||
1419 signal_pending(current))
1420 break;
1421 } else {
1422 if (sock_flag(sk, SOCK_DONE))
1423 break;
1424
1425 if (sk->sk_err) {
1426 copied = sock_error(sk);
1427 break;
1428 }
1429
1430 if (sk->sk_shutdown & RCV_SHUTDOWN)
1431 break;
1432
1433 if (sk->sk_state == TCP_CLOSE) {
1434 if (!sock_flag(sk, SOCK_DONE)) {
1435 /* This occurs when user tries to read
1436 * from never connected socket.
1437 */
1438 copied = -ENOTCONN;
1439 break;
1440 }
1441 break;
1442 }
1443
1444 if (!timeo) {
1445 copied = -EAGAIN;
1446 break;
1447 }
1448
1449 if (signal_pending(current)) {
1450 copied = sock_intr_errno(timeo);
1451 break;
1452 }
1453 }
1454
1455 tcp_cleanup_rbuf(sk, copied);
1456
1457 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1458 /* Install new reader */
1459 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1460 user_recv = current;
1461 tp->ucopy.task = user_recv;
1462 tp->ucopy.iov = msg->msg_iov;
1463 }
1464
1465 tp->ucopy.len = len;
1466
1467 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1468 !(flags & (MSG_PEEK | MSG_TRUNC)));
1469
1470 /* Ugly... If prequeue is not empty, we have to
1471 * process it before releasing socket, otherwise
1472 * order will be broken at second iteration.
1473 * More elegant solution is required!!!
1474 *
1475 * Look: we have the following (pseudo)queues:
1476 *
1477 * 1. packets in flight
1478 * 2. backlog
1479 * 3. prequeue
1480 * 4. receive_queue
1481 *
1482 * Each queue can be processed only if the next ones
1483 * are empty. At this point we have empty receive_queue.
1484 * But prequeue _can_ be not empty after 2nd iteration,
1485 * when we jumped to start of loop because backlog
1486 * processing added something to receive_queue.
1487 * We cannot release_sock(), because backlog contains
1488 * packets arrived _after_ prequeued ones.
1489 *
1490 * Shortly, algorithm is clear --- to process all
1491 * the queues in order. We could make it more directly,
1492 * requeueing packets from backlog to prequeue, if
1493 * is not empty. It is more elegant, but eats cycles,
1494 * unfortunately.
1495 */
1496 if (!skb_queue_empty(&tp->ucopy.prequeue))
1497 goto do_prequeue;
1498
1499 /* __ Set realtime policy in scheduler __ */
1500 }
1501
1502 if (copied >= target) {
1503 /* Do not sleep, just process backlog. */
1504 release_sock(sk);
1505 lock_sock(sk);
1506 } else
1507 sk_wait_data(sk, &timeo);
1508
1509 #ifdef CONFIG_NET_DMA
1510 tp->ucopy.wakeup = 0;
1511 #endif
1512
1513 if (user_recv) {
1514 int chunk;
1515
1516 /* __ Restore normal policy in scheduler __ */
1517
1518 if ((chunk = len - tp->ucopy.len) != 0) {
1519 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1520 len -= chunk;
1521 copied += chunk;
1522 }
1523
1524 if (tp->rcv_nxt == tp->copied_seq &&
1525 !skb_queue_empty(&tp->ucopy.prequeue)) {
1526 do_prequeue:
1527 tcp_prequeue_process(sk);
1528
1529 if ((chunk = len - tp->ucopy.len) != 0) {
1530 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1531 len -= chunk;
1532 copied += chunk;
1533 }
1534 }
1535 }
1536 if ((flags & MSG_PEEK) &&
1537 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1538 if (net_ratelimit())
1539 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1540 current->comm, task_pid_nr(current));
1541 peek_seq = tp->copied_seq;
1542 }
1543 continue;
1544
1545 found_ok_skb:
1546 /* Ok so how much can we use? */
1547 used = skb->len - offset;
1548 if (len < used)
1549 used = len;
1550
1551 /* Do we have urgent data here? */
1552 if (tp->urg_data) {
1553 u32 urg_offset = tp->urg_seq - *seq;
1554 if (urg_offset < used) {
1555 if (!urg_offset) {
1556 if (!sock_flag(sk, SOCK_URGINLINE)) {
1557 ++*seq;
1558 urg_hole++;
1559 offset++;
1560 used--;
1561 if (!used)
1562 goto skip_copy;
1563 }
1564 } else
1565 used = urg_offset;
1566 }
1567 }
1568
1569 if (!(flags & MSG_TRUNC)) {
1570 #ifdef CONFIG_NET_DMA
1571 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1572 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1573
1574 if (tp->ucopy.dma_chan) {
1575 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1576 tp->ucopy.dma_chan, skb, offset,
1577 msg->msg_iov, used,
1578 tp->ucopy.pinned_list);
1579
1580 if (tp->ucopy.dma_cookie < 0) {
1581
1582 printk(KERN_ALERT "dma_cookie < 0\n");
1583
1584 /* Exception. Bailout! */
1585 if (!copied)
1586 copied = -EFAULT;
1587 break;
1588 }
1589 if ((offset + used) == skb->len)
1590 copied_early = 1;
1591
1592 } else
1593 #endif
1594 {
1595 err = skb_copy_datagram_iovec(skb, offset,
1596 msg->msg_iov, used);
1597 if (err) {
1598 /* Exception. Bailout! */
1599 if (!copied)
1600 copied = -EFAULT;
1601 break;
1602 }
1603 }
1604 }
1605
1606 *seq += used;
1607 copied += used;
1608 len -= used;
1609
1610 tcp_rcv_space_adjust(sk);
1611
1612 skip_copy:
1613 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1614 tp->urg_data = 0;
1615 tcp_fast_path_check(sk);
1616 }
1617 if (used + offset < skb->len)
1618 continue;
1619
1620 if (tcp_hdr(skb)->fin)
1621 goto found_fin_ok;
1622 if (!(flags & MSG_PEEK)) {
1623 sk_eat_skb(sk, skb, copied_early);
1624 copied_early = 0;
1625 }
1626 continue;
1627
1628 found_fin_ok:
1629 /* Process the FIN. */
1630 ++*seq;
1631 if (!(flags & MSG_PEEK)) {
1632 sk_eat_skb(sk, skb, copied_early);
1633 copied_early = 0;
1634 }
1635 break;
1636 } while (len > 0);
1637
1638 if (user_recv) {
1639 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1640 int chunk;
1641
1642 tp->ucopy.len = copied > 0 ? len : 0;
1643
1644 tcp_prequeue_process(sk);
1645
1646 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1647 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1648 len -= chunk;
1649 copied += chunk;
1650 }
1651 }
1652
1653 tp->ucopy.task = NULL;
1654 tp->ucopy.len = 0;
1655 }
1656
1657 #ifdef CONFIG_NET_DMA
1658 if (tp->ucopy.dma_chan) {
1659 dma_cookie_t done, used;
1660
1661 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1662
1663 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1664 tp->ucopy.dma_cookie, &done,
1665 &used) == DMA_IN_PROGRESS) {
1666 /* do partial cleanup of sk_async_wait_queue */
1667 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1668 (dma_async_is_complete(skb->dma_cookie, done,
1669 used) == DMA_SUCCESS)) {
1670 __skb_dequeue(&sk->sk_async_wait_queue);
1671 kfree_skb(skb);
1672 }
1673 }
1674
1675 /* Safe to free early-copied skbs now */
1676 __skb_queue_purge(&sk->sk_async_wait_queue);
1677 tp->ucopy.dma_chan = NULL;
1678 }
1679 if (tp->ucopy.pinned_list) {
1680 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1681 tp->ucopy.pinned_list = NULL;
1682 }
1683 #endif
1684
1685 /* According to UNIX98, msg_name/msg_namelen are ignored
1686 * on connected socket. I was just happy when found this 8) --ANK
1687 */
1688
1689 /* Clean up data we have read: This will do ACK frames. */
1690 tcp_cleanup_rbuf(sk, copied);
1691
1692 TCP_CHECK_TIMER(sk);
1693 release_sock(sk);
1694 return copied;
1695
1696 out:
1697 TCP_CHECK_TIMER(sk);
1698 release_sock(sk);
1699 return err;
1700
1701 recv_urg:
1702 err = tcp_recv_urg(sk, msg, len, flags);
1703 goto out;
1704 }
1705
1706 void tcp_set_state(struct sock *sk, int state)
1707 {
1708 int oldstate = sk->sk_state;
1709
1710 switch (state) {
1711 case TCP_ESTABLISHED:
1712 if (oldstate != TCP_ESTABLISHED)
1713 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1714 break;
1715
1716 case TCP_CLOSE:
1717 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1718 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1719
1720 sk->sk_prot->unhash(sk);
1721 if (inet_csk(sk)->icsk_bind_hash &&
1722 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1723 inet_put_port(sk);
1724 /* fall through */
1725 default:
1726 if (oldstate == TCP_ESTABLISHED)
1727 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1728 }
1729
1730 /* Change state AFTER socket is unhashed to avoid closed
1731 * socket sitting in hash tables.
1732 */
1733 sk->sk_state = state;
1734
1735 #ifdef STATE_TRACE
1736 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1737 #endif
1738 }
1739 EXPORT_SYMBOL_GPL(tcp_set_state);
1740
1741 /*
1742 * State processing on a close. This implements the state shift for
1743 * sending our FIN frame. Note that we only send a FIN for some
1744 * states. A shutdown() may have already sent the FIN, or we may be
1745 * closed.
1746 */
1747
1748 static const unsigned char new_state[16] = {
1749 /* current state: new state: action: */
1750 /* (Invalid) */ TCP_CLOSE,
1751 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1752 /* TCP_SYN_SENT */ TCP_CLOSE,
1753 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1754 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1755 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1756 /* TCP_TIME_WAIT */ TCP_CLOSE,
1757 /* TCP_CLOSE */ TCP_CLOSE,
1758 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1759 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1760 /* TCP_LISTEN */ TCP_CLOSE,
1761 /* TCP_CLOSING */ TCP_CLOSING,
1762 };
1763
1764 static int tcp_close_state(struct sock *sk)
1765 {
1766 int next = (int)new_state[sk->sk_state];
1767 int ns = next & TCP_STATE_MASK;
1768
1769 tcp_set_state(sk, ns);
1770
1771 return next & TCP_ACTION_FIN;
1772 }
1773
1774 /*
1775 * Shutdown the sending side of a connection. Much like close except
1776 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1777 */
1778
1779 void tcp_shutdown(struct sock *sk, int how)
1780 {
1781 /* We need to grab some memory, and put together a FIN,
1782 * and then put it into the queue to be sent.
1783 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1784 */
1785 if (!(how & SEND_SHUTDOWN))
1786 return;
1787
1788 /* If we've already sent a FIN, or it's a closed state, skip this. */
1789 if ((1 << sk->sk_state) &
1790 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1791 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1792 /* Clear out any half completed packets. FIN if needed. */
1793 if (tcp_close_state(sk))
1794 tcp_send_fin(sk);
1795 }
1796 }
1797
1798 void tcp_close(struct sock *sk, long timeout)
1799 {
1800 struct sk_buff *skb;
1801 int data_was_unread = 0;
1802 int state;
1803
1804 lock_sock(sk);
1805 sk->sk_shutdown = SHUTDOWN_MASK;
1806
1807 if (sk->sk_state == TCP_LISTEN) {
1808 tcp_set_state(sk, TCP_CLOSE);
1809
1810 /* Special case. */
1811 inet_csk_listen_stop(sk);
1812
1813 goto adjudge_to_death;
1814 }
1815
1816 /* We need to flush the recv. buffs. We do this only on the
1817 * descriptor close, not protocol-sourced closes, because the
1818 * reader process may not have drained the data yet!
1819 */
1820 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1821 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1822 tcp_hdr(skb)->fin;
1823 data_was_unread += len;
1824 __kfree_skb(skb);
1825 }
1826
1827 sk_mem_reclaim(sk);
1828
1829 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1830 * data was lost. To witness the awful effects of the old behavior of
1831 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1832 * GET in an FTP client, suspend the process, wait for the client to
1833 * advertise a zero window, then kill -9 the FTP client, wheee...
1834 * Note: timeout is always zero in such a case.
1835 */
1836 if (data_was_unread) {
1837 /* Unread data was tossed, zap the connection. */
1838 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1839 tcp_set_state(sk, TCP_CLOSE);
1840 tcp_send_active_reset(sk, GFP_KERNEL);
1841 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1842 /* Check zero linger _after_ checking for unread data. */
1843 sk->sk_prot->disconnect(sk, 0);
1844 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1845 } else if (tcp_close_state(sk)) {
1846 /* We FIN if the application ate all the data before
1847 * zapping the connection.
1848 */
1849
1850 /* RED-PEN. Formally speaking, we have broken TCP state
1851 * machine. State transitions:
1852 *
1853 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1854 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1855 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1856 *
1857 * are legal only when FIN has been sent (i.e. in window),
1858 * rather than queued out of window. Purists blame.
1859 *
1860 * F.e. "RFC state" is ESTABLISHED,
1861 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1862 *
1863 * The visible declinations are that sometimes
1864 * we enter time-wait state, when it is not required really
1865 * (harmless), do not send active resets, when they are
1866 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1867 * they look as CLOSING or LAST_ACK for Linux)
1868 * Probably, I missed some more holelets.
1869 * --ANK
1870 */
1871 tcp_send_fin(sk);
1872 }
1873
1874 sk_stream_wait_close(sk, timeout);
1875
1876 adjudge_to_death:
1877 state = sk->sk_state;
1878 sock_hold(sk);
1879 sock_orphan(sk);
1880
1881 /* It is the last release_sock in its life. It will remove backlog. */
1882 release_sock(sk);
1883
1884
1885 /* Now socket is owned by kernel and we acquire BH lock
1886 to finish close. No need to check for user refs.
1887 */
1888 local_bh_disable();
1889 bh_lock_sock(sk);
1890 WARN_ON(sock_owned_by_user(sk));
1891
1892 percpu_counter_inc(sk->sk_prot->orphan_count);
1893
1894 /* Have we already been destroyed by a softirq or backlog? */
1895 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1896 goto out;
1897
1898 /* This is a (useful) BSD violating of the RFC. There is a
1899 * problem with TCP as specified in that the other end could
1900 * keep a socket open forever with no application left this end.
1901 * We use a 3 minute timeout (about the same as BSD) then kill
1902 * our end. If they send after that then tough - BUT: long enough
1903 * that we won't make the old 4*rto = almost no time - whoops
1904 * reset mistake.
1905 *
1906 * Nope, it was not mistake. It is really desired behaviour
1907 * f.e. on http servers, when such sockets are useless, but
1908 * consume significant resources. Let's do it with special
1909 * linger2 option. --ANK
1910 */
1911
1912 if (sk->sk_state == TCP_FIN_WAIT2) {
1913 struct tcp_sock *tp = tcp_sk(sk);
1914 if (tp->linger2 < 0) {
1915 tcp_set_state(sk, TCP_CLOSE);
1916 tcp_send_active_reset(sk, GFP_ATOMIC);
1917 NET_INC_STATS_BH(sock_net(sk),
1918 LINUX_MIB_TCPABORTONLINGER);
1919 } else {
1920 const int tmo = tcp_fin_time(sk);
1921
1922 if (tmo > TCP_TIMEWAIT_LEN) {
1923 inet_csk_reset_keepalive_timer(sk,
1924 tmo - TCP_TIMEWAIT_LEN);
1925 } else {
1926 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1927 goto out;
1928 }
1929 }
1930 }
1931 if (sk->sk_state != TCP_CLOSE) {
1932 int orphan_count = percpu_counter_read_positive(
1933 sk->sk_prot->orphan_count);
1934
1935 sk_mem_reclaim(sk);
1936 if (tcp_too_many_orphans(sk, orphan_count)) {
1937 if (net_ratelimit())
1938 printk(KERN_INFO "TCP: too many of orphaned "
1939 "sockets\n");
1940 tcp_set_state(sk, TCP_CLOSE);
1941 tcp_send_active_reset(sk, GFP_ATOMIC);
1942 NET_INC_STATS_BH(sock_net(sk),
1943 LINUX_MIB_TCPABORTONMEMORY);
1944 }
1945 }
1946
1947 if (sk->sk_state == TCP_CLOSE)
1948 inet_csk_destroy_sock(sk);
1949 /* Otherwise, socket is reprieved until protocol close. */
1950
1951 out:
1952 bh_unlock_sock(sk);
1953 local_bh_enable();
1954 sock_put(sk);
1955 }
1956
1957 /* These states need RST on ABORT according to RFC793 */
1958
1959 static inline int tcp_need_reset(int state)
1960 {
1961 return (1 << state) &
1962 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1963 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1964 }
1965
1966 int tcp_disconnect(struct sock *sk, int flags)
1967 {
1968 struct inet_sock *inet = inet_sk(sk);
1969 struct inet_connection_sock *icsk = inet_csk(sk);
1970 struct tcp_sock *tp = tcp_sk(sk);
1971 int err = 0;
1972 int old_state = sk->sk_state;
1973
1974 if (old_state != TCP_CLOSE)
1975 tcp_set_state(sk, TCP_CLOSE);
1976
1977 /* ABORT function of RFC793 */
1978 if (old_state == TCP_LISTEN) {
1979 inet_csk_listen_stop(sk);
1980 } else if (tcp_need_reset(old_state) ||
1981 (tp->snd_nxt != tp->write_seq &&
1982 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1983 /* The last check adjusts for discrepancy of Linux wrt. RFC
1984 * states
1985 */
1986 tcp_send_active_reset(sk, gfp_any());
1987 sk->sk_err = ECONNRESET;
1988 } else if (old_state == TCP_SYN_SENT)
1989 sk->sk_err = ECONNRESET;
1990
1991 tcp_clear_xmit_timers(sk);
1992 __skb_queue_purge(&sk->sk_receive_queue);
1993 tcp_write_queue_purge(sk);
1994 __skb_queue_purge(&tp->out_of_order_queue);
1995 #ifdef CONFIG_NET_DMA
1996 __skb_queue_purge(&sk->sk_async_wait_queue);
1997 #endif
1998
1999 inet->dport = 0;
2000
2001 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2002 inet_reset_saddr(sk);
2003
2004 sk->sk_shutdown = 0;
2005 sock_reset_flag(sk, SOCK_DONE);
2006 tp->srtt = 0;
2007 if ((tp->write_seq += tp->max_window + 2) == 0)
2008 tp->write_seq = 1;
2009 icsk->icsk_backoff = 0;
2010 tp->snd_cwnd = 2;
2011 icsk->icsk_probes_out = 0;
2012 tp->packets_out = 0;
2013 tp->snd_ssthresh = 0x7fffffff;
2014 tp->snd_cwnd_cnt = 0;
2015 tp->bytes_acked = 0;
2016 tcp_set_ca_state(sk, TCP_CA_Open);
2017 tcp_clear_retrans(tp);
2018 inet_csk_delack_init(sk);
2019 tcp_init_send_head(sk);
2020 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2021 __sk_dst_reset(sk);
2022
2023 WARN_ON(inet->num && !icsk->icsk_bind_hash);
2024
2025 sk->sk_error_report(sk);
2026 return err;
2027 }
2028
2029 /*
2030 * Socket option code for TCP.
2031 */
2032 static int do_tcp_setsockopt(struct sock *sk, int level,
2033 int optname, char __user *optval, int optlen)
2034 {
2035 struct tcp_sock *tp = tcp_sk(sk);
2036 struct inet_connection_sock *icsk = inet_csk(sk);
2037 int val;
2038 int err = 0;
2039
2040 /* This is a string value all the others are int's */
2041 if (optname == TCP_CONGESTION) {
2042 char name[TCP_CA_NAME_MAX];
2043
2044 if (optlen < 1)
2045 return -EINVAL;
2046
2047 val = strncpy_from_user(name, optval,
2048 min(TCP_CA_NAME_MAX-1, optlen));
2049 if (val < 0)
2050 return -EFAULT;
2051 name[val] = 0;
2052
2053 lock_sock(sk);
2054 err = tcp_set_congestion_control(sk, name);
2055 release_sock(sk);
2056 return err;
2057 }
2058
2059 if (optlen < sizeof(int))
2060 return -EINVAL;
2061
2062 if (get_user(val, (int __user *)optval))
2063 return -EFAULT;
2064
2065 lock_sock(sk);
2066
2067 switch (optname) {
2068 case TCP_MAXSEG:
2069 /* Values greater than interface MTU won't take effect. However
2070 * at the point when this call is done we typically don't yet
2071 * know which interface is going to be used */
2072 if (val < 8 || val > MAX_TCP_WINDOW) {
2073 err = -EINVAL;
2074 break;
2075 }
2076 tp->rx_opt.user_mss = val;
2077 break;
2078
2079 case TCP_NODELAY:
2080 if (val) {
2081 /* TCP_NODELAY is weaker than TCP_CORK, so that
2082 * this option on corked socket is remembered, but
2083 * it is not activated until cork is cleared.
2084 *
2085 * However, when TCP_NODELAY is set we make
2086 * an explicit push, which overrides even TCP_CORK
2087 * for currently queued segments.
2088 */
2089 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2090 tcp_push_pending_frames(sk);
2091 } else {
2092 tp->nonagle &= ~TCP_NAGLE_OFF;
2093 }
2094 break;
2095
2096 case TCP_CORK:
2097 /* When set indicates to always queue non-full frames.
2098 * Later the user clears this option and we transmit
2099 * any pending partial frames in the queue. This is
2100 * meant to be used alongside sendfile() to get properly
2101 * filled frames when the user (for example) must write
2102 * out headers with a write() call first and then use
2103 * sendfile to send out the data parts.
2104 *
2105 * TCP_CORK can be set together with TCP_NODELAY and it is
2106 * stronger than TCP_NODELAY.
2107 */
2108 if (val) {
2109 tp->nonagle |= TCP_NAGLE_CORK;
2110 } else {
2111 tp->nonagle &= ~TCP_NAGLE_CORK;
2112 if (tp->nonagle&TCP_NAGLE_OFF)
2113 tp->nonagle |= TCP_NAGLE_PUSH;
2114 tcp_push_pending_frames(sk);
2115 }
2116 break;
2117
2118 case TCP_KEEPIDLE:
2119 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2120 err = -EINVAL;
2121 else {
2122 tp->keepalive_time = val * HZ;
2123 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2124 !((1 << sk->sk_state) &
2125 (TCPF_CLOSE | TCPF_LISTEN))) {
2126 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2127 if (tp->keepalive_time > elapsed)
2128 elapsed = tp->keepalive_time - elapsed;
2129 else
2130 elapsed = 0;
2131 inet_csk_reset_keepalive_timer(sk, elapsed);
2132 }
2133 }
2134 break;
2135 case TCP_KEEPINTVL:
2136 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2137 err = -EINVAL;
2138 else
2139 tp->keepalive_intvl = val * HZ;
2140 break;
2141 case TCP_KEEPCNT:
2142 if (val < 1 || val > MAX_TCP_KEEPCNT)
2143 err = -EINVAL;
2144 else
2145 tp->keepalive_probes = val;
2146 break;
2147 case TCP_SYNCNT:
2148 if (val < 1 || val > MAX_TCP_SYNCNT)
2149 err = -EINVAL;
2150 else
2151 icsk->icsk_syn_retries = val;
2152 break;
2153
2154 case TCP_LINGER2:
2155 if (val < 0)
2156 tp->linger2 = -1;
2157 else if (val > sysctl_tcp_fin_timeout / HZ)
2158 tp->linger2 = 0;
2159 else
2160 tp->linger2 = val * HZ;
2161 break;
2162
2163 case TCP_DEFER_ACCEPT:
2164 icsk->icsk_accept_queue.rskq_defer_accept = 0;
2165 if (val > 0) {
2166 /* Translate value in seconds to number of
2167 * retransmits */
2168 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
2169 val > ((TCP_TIMEOUT_INIT / HZ) <<
2170 icsk->icsk_accept_queue.rskq_defer_accept))
2171 icsk->icsk_accept_queue.rskq_defer_accept++;
2172 icsk->icsk_accept_queue.rskq_defer_accept++;
2173 }
2174 break;
2175
2176 case TCP_WINDOW_CLAMP:
2177 if (!val) {
2178 if (sk->sk_state != TCP_CLOSE) {
2179 err = -EINVAL;
2180 break;
2181 }
2182 tp->window_clamp = 0;
2183 } else
2184 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2185 SOCK_MIN_RCVBUF / 2 : val;
2186 break;
2187
2188 case TCP_QUICKACK:
2189 if (!val) {
2190 icsk->icsk_ack.pingpong = 1;
2191 } else {
2192 icsk->icsk_ack.pingpong = 0;
2193 if ((1 << sk->sk_state) &
2194 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2195 inet_csk_ack_scheduled(sk)) {
2196 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2197 tcp_cleanup_rbuf(sk, 1);
2198 if (!(val & 1))
2199 icsk->icsk_ack.pingpong = 1;
2200 }
2201 }
2202 break;
2203
2204 #ifdef CONFIG_TCP_MD5SIG
2205 case TCP_MD5SIG:
2206 /* Read the IP->Key mappings from userspace */
2207 err = tp->af_specific->md5_parse(sk, optval, optlen);
2208 break;
2209 #endif
2210
2211 default:
2212 err = -ENOPROTOOPT;
2213 break;
2214 }
2215
2216 release_sock(sk);
2217 return err;
2218 }
2219
2220 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2221 int optlen)
2222 {
2223 struct inet_connection_sock *icsk = inet_csk(sk);
2224
2225 if (level != SOL_TCP)
2226 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2227 optval, optlen);
2228 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2229 }
2230
2231 #ifdef CONFIG_COMPAT
2232 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2233 char __user *optval, int optlen)
2234 {
2235 if (level != SOL_TCP)
2236 return inet_csk_compat_setsockopt(sk, level, optname,
2237 optval, optlen);
2238 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2239 }
2240
2241 EXPORT_SYMBOL(compat_tcp_setsockopt);
2242 #endif
2243
2244 /* Return information about state of tcp endpoint in API format. */
2245 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2246 {
2247 struct tcp_sock *tp = tcp_sk(sk);
2248 const struct inet_connection_sock *icsk = inet_csk(sk);
2249 u32 now = tcp_time_stamp;
2250
2251 memset(info, 0, sizeof(*info));
2252
2253 info->tcpi_state = sk->sk_state;
2254 info->tcpi_ca_state = icsk->icsk_ca_state;
2255 info->tcpi_retransmits = icsk->icsk_retransmits;
2256 info->tcpi_probes = icsk->icsk_probes_out;
2257 info->tcpi_backoff = icsk->icsk_backoff;
2258
2259 if (tp->rx_opt.tstamp_ok)
2260 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2261 if (tcp_is_sack(tp))
2262 info->tcpi_options |= TCPI_OPT_SACK;
2263 if (tp->rx_opt.wscale_ok) {
2264 info->tcpi_options |= TCPI_OPT_WSCALE;
2265 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2266 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2267 }
2268
2269 if (tp->ecn_flags&TCP_ECN_OK)
2270 info->tcpi_options |= TCPI_OPT_ECN;
2271
2272 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2273 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2274 info->tcpi_snd_mss = tp->mss_cache;
2275 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2276
2277 if (sk->sk_state == TCP_LISTEN) {
2278 info->tcpi_unacked = sk->sk_ack_backlog;
2279 info->tcpi_sacked = sk->sk_max_ack_backlog;
2280 } else {
2281 info->tcpi_unacked = tp->packets_out;
2282 info->tcpi_sacked = tp->sacked_out;
2283 }
2284 info->tcpi_lost = tp->lost_out;
2285 info->tcpi_retrans = tp->retrans_out;
2286 info->tcpi_fackets = tp->fackets_out;
2287
2288 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2289 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2290 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2291
2292 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2293 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2294 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2295 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2296 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2297 info->tcpi_snd_cwnd = tp->snd_cwnd;
2298 info->tcpi_advmss = tp->advmss;
2299 info->tcpi_reordering = tp->reordering;
2300
2301 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2302 info->tcpi_rcv_space = tp->rcvq_space.space;
2303
2304 info->tcpi_total_retrans = tp->total_retrans;
2305 }
2306
2307 EXPORT_SYMBOL_GPL(tcp_get_info);
2308
2309 static int do_tcp_getsockopt(struct sock *sk, int level,
2310 int optname, char __user *optval, int __user *optlen)
2311 {
2312 struct inet_connection_sock *icsk = inet_csk(sk);
2313 struct tcp_sock *tp = tcp_sk(sk);
2314 int val, len;
2315
2316 if (get_user(len, optlen))
2317 return -EFAULT;
2318
2319 len = min_t(unsigned int, len, sizeof(int));
2320
2321 if (len < 0)
2322 return -EINVAL;
2323
2324 switch (optname) {
2325 case TCP_MAXSEG:
2326 val = tp->mss_cache;
2327 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2328 val = tp->rx_opt.user_mss;
2329 break;
2330 case TCP_NODELAY:
2331 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2332 break;
2333 case TCP_CORK:
2334 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2335 break;
2336 case TCP_KEEPIDLE:
2337 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2338 break;
2339 case TCP_KEEPINTVL:
2340 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2341 break;
2342 case TCP_KEEPCNT:
2343 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2344 break;
2345 case TCP_SYNCNT:
2346 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2347 break;
2348 case TCP_LINGER2:
2349 val = tp->linger2;
2350 if (val >= 0)
2351 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2352 break;
2353 case TCP_DEFER_ACCEPT:
2354 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2355 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2356 break;
2357 case TCP_WINDOW_CLAMP:
2358 val = tp->window_clamp;
2359 break;
2360 case TCP_INFO: {
2361 struct tcp_info info;
2362
2363 if (get_user(len, optlen))
2364 return -EFAULT;
2365
2366 tcp_get_info(sk, &info);
2367
2368 len = min_t(unsigned int, len, sizeof(info));
2369 if (put_user(len, optlen))
2370 return -EFAULT;
2371 if (copy_to_user(optval, &info, len))
2372 return -EFAULT;
2373 return 0;
2374 }
2375 case TCP_QUICKACK:
2376 val = !icsk->icsk_ack.pingpong;
2377 break;
2378
2379 case TCP_CONGESTION:
2380 if (get_user(len, optlen))
2381 return -EFAULT;
2382 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2383 if (put_user(len, optlen))
2384 return -EFAULT;
2385 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2386 return -EFAULT;
2387 return 0;
2388 default:
2389 return -ENOPROTOOPT;
2390 }
2391
2392 if (put_user(len, optlen))
2393 return -EFAULT;
2394 if (copy_to_user(optval, &val, len))
2395 return -EFAULT;
2396 return 0;
2397 }
2398
2399 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2400 int __user *optlen)
2401 {
2402 struct inet_connection_sock *icsk = inet_csk(sk);
2403
2404 if (level != SOL_TCP)
2405 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2406 optval, optlen);
2407 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2408 }
2409
2410 #ifdef CONFIG_COMPAT
2411 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2412 char __user *optval, int __user *optlen)
2413 {
2414 if (level != SOL_TCP)
2415 return inet_csk_compat_getsockopt(sk, level, optname,
2416 optval, optlen);
2417 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2418 }
2419
2420 EXPORT_SYMBOL(compat_tcp_getsockopt);
2421 #endif
2422
2423 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2424 {
2425 struct sk_buff *segs = ERR_PTR(-EINVAL);
2426 struct tcphdr *th;
2427 unsigned thlen;
2428 unsigned int seq;
2429 __be32 delta;
2430 unsigned int oldlen;
2431 unsigned int mss;
2432
2433 if (!pskb_may_pull(skb, sizeof(*th)))
2434 goto out;
2435
2436 th = tcp_hdr(skb);
2437 thlen = th->doff * 4;
2438 if (thlen < sizeof(*th))
2439 goto out;
2440
2441 if (!pskb_may_pull(skb, thlen))
2442 goto out;
2443
2444 oldlen = (u16)~skb->len;
2445 __skb_pull(skb, thlen);
2446
2447 mss = skb_shinfo(skb)->gso_size;
2448 if (unlikely(skb->len <= mss))
2449 goto out;
2450
2451 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2452 /* Packet is from an untrusted source, reset gso_segs. */
2453 int type = skb_shinfo(skb)->gso_type;
2454
2455 if (unlikely(type &
2456 ~(SKB_GSO_TCPV4 |
2457 SKB_GSO_DODGY |
2458 SKB_GSO_TCP_ECN |
2459 SKB_GSO_TCPV6 |
2460 0) ||
2461 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2462 goto out;
2463
2464 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2465
2466 segs = NULL;
2467 goto out;
2468 }
2469
2470 segs = skb_segment(skb, features);
2471 if (IS_ERR(segs))
2472 goto out;
2473
2474 delta = htonl(oldlen + (thlen + mss));
2475
2476 skb = segs;
2477 th = tcp_hdr(skb);
2478 seq = ntohl(th->seq);
2479
2480 do {
2481 th->fin = th->psh = 0;
2482
2483 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2484 (__force u32)delta));
2485 if (skb->ip_summed != CHECKSUM_PARTIAL)
2486 th->check =
2487 csum_fold(csum_partial(skb_transport_header(skb),
2488 thlen, skb->csum));
2489
2490 seq += mss;
2491 skb = skb->next;
2492 th = tcp_hdr(skb);
2493
2494 th->seq = htonl(seq);
2495 th->cwr = 0;
2496 } while (skb->next);
2497
2498 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2499 skb->data_len);
2500 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2501 (__force u32)delta));
2502 if (skb->ip_summed != CHECKSUM_PARTIAL)
2503 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2504 thlen, skb->csum));
2505
2506 out:
2507 return segs;
2508 }
2509 EXPORT_SYMBOL(tcp_tso_segment);
2510
2511 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2512 {
2513 struct sk_buff **pp = NULL;
2514 struct sk_buff *p;
2515 struct tcphdr *th;
2516 struct tcphdr *th2;
2517 unsigned int len;
2518 unsigned int thlen;
2519 unsigned int flags;
2520 unsigned int mss = 1;
2521 int flush = 1;
2522 int i;
2523
2524 th = skb_gro_header(skb, sizeof(*th));
2525 if (unlikely(!th))
2526 goto out;
2527
2528 thlen = th->doff * 4;
2529 if (thlen < sizeof(*th))
2530 goto out;
2531
2532 th = skb_gro_header(skb, thlen);
2533 if (unlikely(!th))
2534 goto out;
2535
2536 skb_gro_pull(skb, thlen);
2537
2538 len = skb_gro_len(skb);
2539 flags = tcp_flag_word(th);
2540
2541 for (; (p = *head); head = &p->next) {
2542 if (!NAPI_GRO_CB(p)->same_flow)
2543 continue;
2544
2545 th2 = tcp_hdr(p);
2546
2547 if ((th->source ^ th2->source) | (th->dest ^ th2->dest)) {
2548 NAPI_GRO_CB(p)->same_flow = 0;
2549 continue;
2550 }
2551
2552 goto found;
2553 }
2554
2555 goto out_check_final;
2556
2557 found:
2558 flush = NAPI_GRO_CB(p)->flush;
2559 flush |= flags & TCP_FLAG_CWR;
2560 flush |= (flags ^ tcp_flag_word(th2)) &
2561 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH);
2562 flush |= (th->ack_seq ^ th2->ack_seq) | (th->window ^ th2->window);
2563 for (i = sizeof(*th); !flush && i < thlen; i += 4)
2564 flush |= *(u32 *)((u8 *)th + i) ^
2565 *(u32 *)((u8 *)th2 + i);
2566
2567 mss = skb_shinfo(p)->gso_size;
2568
2569 flush |= (len > mss) | !len;
2570 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2571
2572 if (flush || skb_gro_receive(head, skb)) {
2573 mss = 1;
2574 goto out_check_final;
2575 }
2576
2577 p = *head;
2578 th2 = tcp_hdr(p);
2579 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2580
2581 out_check_final:
2582 flush = len < mss;
2583 flush |= flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST |
2584 TCP_FLAG_SYN | TCP_FLAG_FIN);
2585
2586 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2587 pp = head;
2588
2589 out:
2590 NAPI_GRO_CB(skb)->flush |= flush;
2591
2592 return pp;
2593 }
2594 EXPORT_SYMBOL(tcp_gro_receive);
2595
2596 int tcp_gro_complete(struct sk_buff *skb)
2597 {
2598 struct tcphdr *th = tcp_hdr(skb);
2599
2600 skb->csum_start = skb_transport_header(skb) - skb->head;
2601 skb->csum_offset = offsetof(struct tcphdr, check);
2602 skb->ip_summed = CHECKSUM_PARTIAL;
2603
2604 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2605
2606 if (th->cwr)
2607 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2608
2609 return 0;
2610 }
2611 EXPORT_SYMBOL(tcp_gro_complete);
2612
2613 #ifdef CONFIG_TCP_MD5SIG
2614 static unsigned long tcp_md5sig_users;
2615 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2616 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2617
2618 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2619 {
2620 int cpu;
2621 for_each_possible_cpu(cpu) {
2622 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2623 if (p) {
2624 if (p->md5_desc.tfm)
2625 crypto_free_hash(p->md5_desc.tfm);
2626 kfree(p);
2627 p = NULL;
2628 }
2629 }
2630 free_percpu(pool);
2631 }
2632
2633 void tcp_free_md5sig_pool(void)
2634 {
2635 struct tcp_md5sig_pool **pool = NULL;
2636
2637 spin_lock_bh(&tcp_md5sig_pool_lock);
2638 if (--tcp_md5sig_users == 0) {
2639 pool = tcp_md5sig_pool;
2640 tcp_md5sig_pool = NULL;
2641 }
2642 spin_unlock_bh(&tcp_md5sig_pool_lock);
2643 if (pool)
2644 __tcp_free_md5sig_pool(pool);
2645 }
2646
2647 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2648
2649 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
2650 {
2651 int cpu;
2652 struct tcp_md5sig_pool **pool;
2653
2654 pool = alloc_percpu(struct tcp_md5sig_pool *);
2655 if (!pool)
2656 return NULL;
2657
2658 for_each_possible_cpu(cpu) {
2659 struct tcp_md5sig_pool *p;
2660 struct crypto_hash *hash;
2661
2662 p = kzalloc(sizeof(*p), GFP_KERNEL);
2663 if (!p)
2664 goto out_free;
2665 *per_cpu_ptr(pool, cpu) = p;
2666
2667 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2668 if (!hash || IS_ERR(hash))
2669 goto out_free;
2670
2671 p->md5_desc.tfm = hash;
2672 }
2673 return pool;
2674 out_free:
2675 __tcp_free_md5sig_pool(pool);
2676 return NULL;
2677 }
2678
2679 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
2680 {
2681 struct tcp_md5sig_pool **pool;
2682 int alloc = 0;
2683
2684 retry:
2685 spin_lock_bh(&tcp_md5sig_pool_lock);
2686 pool = tcp_md5sig_pool;
2687 if (tcp_md5sig_users++ == 0) {
2688 alloc = 1;
2689 spin_unlock_bh(&tcp_md5sig_pool_lock);
2690 } else if (!pool) {
2691 tcp_md5sig_users--;
2692 spin_unlock_bh(&tcp_md5sig_pool_lock);
2693 cpu_relax();
2694 goto retry;
2695 } else
2696 spin_unlock_bh(&tcp_md5sig_pool_lock);
2697
2698 if (alloc) {
2699 /* we cannot hold spinlock here because this may sleep. */
2700 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
2701 spin_lock_bh(&tcp_md5sig_pool_lock);
2702 if (!p) {
2703 tcp_md5sig_users--;
2704 spin_unlock_bh(&tcp_md5sig_pool_lock);
2705 return NULL;
2706 }
2707 pool = tcp_md5sig_pool;
2708 if (pool) {
2709 /* oops, it has already been assigned. */
2710 spin_unlock_bh(&tcp_md5sig_pool_lock);
2711 __tcp_free_md5sig_pool(p);
2712 } else {
2713 tcp_md5sig_pool = pool = p;
2714 spin_unlock_bh(&tcp_md5sig_pool_lock);
2715 }
2716 }
2717 return pool;
2718 }
2719
2720 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2721
2722 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2723 {
2724 struct tcp_md5sig_pool **p;
2725 spin_lock_bh(&tcp_md5sig_pool_lock);
2726 p = tcp_md5sig_pool;
2727 if (p)
2728 tcp_md5sig_users++;
2729 spin_unlock_bh(&tcp_md5sig_pool_lock);
2730 return (p ? *per_cpu_ptr(p, cpu) : NULL);
2731 }
2732
2733 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2734
2735 void __tcp_put_md5sig_pool(void)
2736 {
2737 tcp_free_md5sig_pool();
2738 }
2739
2740 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2741
2742 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2743 struct tcphdr *th)
2744 {
2745 struct scatterlist sg;
2746 int err;
2747
2748 __sum16 old_checksum = th->check;
2749 th->check = 0;
2750 /* options aren't included in the hash */
2751 sg_init_one(&sg, th, sizeof(struct tcphdr));
2752 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
2753 th->check = old_checksum;
2754 return err;
2755 }
2756
2757 EXPORT_SYMBOL(tcp_md5_hash_header);
2758
2759 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2760 struct sk_buff *skb, unsigned header_len)
2761 {
2762 struct scatterlist sg;
2763 const struct tcphdr *tp = tcp_hdr(skb);
2764 struct hash_desc *desc = &hp->md5_desc;
2765 unsigned i;
2766 const unsigned head_data_len = skb_headlen(skb) > header_len ?
2767 skb_headlen(skb) - header_len : 0;
2768 const struct skb_shared_info *shi = skb_shinfo(skb);
2769
2770 sg_init_table(&sg, 1);
2771
2772 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2773 if (crypto_hash_update(desc, &sg, head_data_len))
2774 return 1;
2775
2776 for (i = 0; i < shi->nr_frags; ++i) {
2777 const struct skb_frag_struct *f = &shi->frags[i];
2778 sg_set_page(&sg, f->page, f->size, f->page_offset);
2779 if (crypto_hash_update(desc, &sg, f->size))
2780 return 1;
2781 }
2782
2783 return 0;
2784 }
2785
2786 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
2787
2788 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
2789 {
2790 struct scatterlist sg;
2791
2792 sg_init_one(&sg, key->key, key->keylen);
2793 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
2794 }
2795
2796 EXPORT_SYMBOL(tcp_md5_hash_key);
2797
2798 #endif
2799
2800 void tcp_done(struct sock *sk)
2801 {
2802 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2803 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
2804
2805 tcp_set_state(sk, TCP_CLOSE);
2806 tcp_clear_xmit_timers(sk);
2807
2808 sk->sk_shutdown = SHUTDOWN_MASK;
2809
2810 if (!sock_flag(sk, SOCK_DEAD))
2811 sk->sk_state_change(sk);
2812 else
2813 inet_csk_destroy_sock(sk);
2814 }
2815 EXPORT_SYMBOL_GPL(tcp_done);
2816
2817 extern struct tcp_congestion_ops tcp_reno;
2818
2819 static __initdata unsigned long thash_entries;
2820 static int __init set_thash_entries(char *str)
2821 {
2822 if (!str)
2823 return 0;
2824 thash_entries = simple_strtoul(str, &str, 0);
2825 return 1;
2826 }
2827 __setup("thash_entries=", set_thash_entries);
2828
2829 void __init tcp_init(void)
2830 {
2831 struct sk_buff *skb = NULL;
2832 unsigned long nr_pages, limit;
2833 int order, i, max_share;
2834
2835 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
2836
2837 percpu_counter_init(&tcp_sockets_allocated, 0);
2838 percpu_counter_init(&tcp_orphan_count, 0);
2839 tcp_hashinfo.bind_bucket_cachep =
2840 kmem_cache_create("tcp_bind_bucket",
2841 sizeof(struct inet_bind_bucket), 0,
2842 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2843
2844 /* Size and allocate the main established and bind bucket
2845 * hash tables.
2846 *
2847 * The methodology is similar to that of the buffer cache.
2848 */
2849 tcp_hashinfo.ehash =
2850 alloc_large_system_hash("TCP established",
2851 sizeof(struct inet_ehash_bucket),
2852 thash_entries,
2853 (num_physpages >= 128 * 1024) ?
2854 13 : 15,
2855 0,
2856 &tcp_hashinfo.ehash_size,
2857 NULL,
2858 thash_entries ? 0 : 512 * 1024);
2859 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2860 for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2861 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
2862 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
2863 }
2864 if (inet_ehash_locks_alloc(&tcp_hashinfo))
2865 panic("TCP: failed to alloc ehash_locks");
2866 tcp_hashinfo.bhash =
2867 alloc_large_system_hash("TCP bind",
2868 sizeof(struct inet_bind_hashbucket),
2869 tcp_hashinfo.ehash_size,
2870 (num_physpages >= 128 * 1024) ?
2871 13 : 15,
2872 0,
2873 &tcp_hashinfo.bhash_size,
2874 NULL,
2875 64 * 1024);
2876 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2877 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2878 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2879 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2880 }
2881
2882 /* Try to be a bit smarter and adjust defaults depending
2883 * on available memory.
2884 */
2885 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2886 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2887 order++)
2888 ;
2889 if (order >= 4) {
2890 tcp_death_row.sysctl_max_tw_buckets = 180000;
2891 sysctl_tcp_max_orphans = 4096 << (order - 4);
2892 sysctl_max_syn_backlog = 1024;
2893 } else if (order < 3) {
2894 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2895 sysctl_tcp_max_orphans >>= (3 - order);
2896 sysctl_max_syn_backlog = 128;
2897 }
2898
2899 /* Set the pressure threshold to be a fraction of global memory that
2900 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2901 * memory, with a floor of 128 pages.
2902 */
2903 nr_pages = totalram_pages - totalhigh_pages;
2904 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
2905 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
2906 limit = max(limit, 128UL);
2907 sysctl_tcp_mem[0] = limit / 4 * 3;
2908 sysctl_tcp_mem[1] = limit;
2909 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
2910
2911 /* Set per-socket limits to no more than 1/128 the pressure threshold */
2912 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2913 max_share = min(4UL*1024*1024, limit);
2914
2915 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
2916 sysctl_tcp_wmem[1] = 16*1024;
2917 sysctl_tcp_wmem[2] = max(64*1024, max_share);
2918
2919 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
2920 sysctl_tcp_rmem[1] = 87380;
2921 sysctl_tcp_rmem[2] = max(87380, max_share);
2922
2923 printk(KERN_INFO "TCP: Hash tables configured "
2924 "(established %d bind %d)\n",
2925 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
2926
2927 tcp_register_congestion_control(&tcp_reno);
2928 }
2929
2930 EXPORT_SYMBOL(tcp_close);
2931 EXPORT_SYMBOL(tcp_disconnect);
2932 EXPORT_SYMBOL(tcp_getsockopt);
2933 EXPORT_SYMBOL(tcp_ioctl);
2934 EXPORT_SYMBOL(tcp_poll);
2935 EXPORT_SYMBOL(tcp_read_sock);
2936 EXPORT_SYMBOL(tcp_recvmsg);
2937 EXPORT_SYMBOL(tcp_sendmsg);
2938 EXPORT_SYMBOL(tcp_splice_read);
2939 EXPORT_SYMBOL(tcp_sendpage);
2940 EXPORT_SYMBOL(tcp_setsockopt);
2941 EXPORT_SYMBOL(tcp_shutdown);
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