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Merge branch 'mini2440-dev-unlikely' into mini2440-dev
[linux-2.6/mini2440.git] / net / ipv4 / tcp.c
blobf1813bc7108811a50ff8284775ad053623903a2e
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 /* Convert seconds to retransmits based on initial and max timeout */
330 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
331 {
332 u8 res = 0;
333
334 if (seconds > 0) {
335 int period = timeout;
336
337 res = 1;
338 while (seconds > period && res < 255) {
339 res++;
340 timeout <<= 1;
341 if (timeout > rto_max)
342 timeout = rto_max;
343 period += timeout;
344 }
345 }
346 return res;
347 }
348
349 /* Convert retransmits to seconds based on initial and max timeout */
350 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
351 {
352 int period = 0;
353
354 if (retrans > 0) {
355 period = timeout;
356 while (--retrans) {
357 timeout <<= 1;
358 if (timeout > rto_max)
359 timeout = rto_max;
360 period += timeout;
361 }
362 }
363 return period;
364 }
365
366 /*
367 * Wait for a TCP event.
368 *
369 * Note that we don't need to lock the socket, as the upper poll layers
370 * take care of normal races (between the test and the event) and we don't
371 * go look at any of the socket buffers directly.
372 */
373 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
374 {
375 unsigned int mask;
376 struct sock *sk = sock->sk;
377 struct tcp_sock *tp = tcp_sk(sk);
378
379 sock_poll_wait(file, sk->sk_sleep, wait);
380 if (sk->sk_state == TCP_LISTEN)
381 return inet_csk_listen_poll(sk);
382
383 /* Socket is not locked. We are protected from async events
384 * by poll logic and correct handling of state changes
385 * made by other threads is impossible in any case.
386 */
387
388 mask = 0;
389 if (sk->sk_err)
390 mask = POLLERR;
391
392 /*
393 * POLLHUP is certainly not done right. But poll() doesn't
394 * have a notion of HUP in just one direction, and for a
395 * socket the read side is more interesting.
396 *
397 * Some poll() documentation says that POLLHUP is incompatible
398 * with the POLLOUT/POLLWR flags, so somebody should check this
399 * all. But careful, it tends to be safer to return too many
400 * bits than too few, and you can easily break real applications
401 * if you don't tell them that something has hung up!
402 *
403 * Check-me.
404 *
405 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
406 * our fs/select.c). It means that after we received EOF,
407 * poll always returns immediately, making impossible poll() on write()
408 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
409 * if and only if shutdown has been made in both directions.
410 * Actually, it is interesting to look how Solaris and DUX
411 * solve this dilemma. I would prefer, if POLLHUP were maskable,
412 * then we could set it on SND_SHUTDOWN. BTW examples given
413 * in Stevens' books assume exactly this behaviour, it explains
414 * why POLLHUP is incompatible with POLLOUT. --ANK
415 *
416 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
417 * blocking on fresh not-connected or disconnected socket. --ANK
418 */
419 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
420 mask |= POLLHUP;
421 if (sk->sk_shutdown & RCV_SHUTDOWN)
422 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
423
424 /* Connected? */
425 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
426 int target = sock_rcvlowat(sk, 0, INT_MAX);
427
428 if (tp->urg_seq == tp->copied_seq &&
429 !sock_flag(sk, SOCK_URGINLINE) &&
430 tp->urg_data)
431 target--;
432
433 /* Potential race condition. If read of tp below will
434 * escape above sk->sk_state, we can be illegally awaken
435 * in SYN_* states. */
436 if (tp->rcv_nxt - tp->copied_seq >= target)
437 mask |= POLLIN | POLLRDNORM;
438
439 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
440 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
441 mask |= POLLOUT | POLLWRNORM;
442 } else { /* send SIGIO later */
443 set_bit(SOCK_ASYNC_NOSPACE,
444 &sk->sk_socket->flags);
445 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
446
447 /* Race breaker. If space is freed after
448 * wspace test but before the flags are set,
449 * IO signal will be lost.
450 */
451 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
452 mask |= POLLOUT | POLLWRNORM;
453 }
454 }
455
456 if (tp->urg_data & TCP_URG_VALID)
457 mask |= POLLPRI;
458 }
459 return mask;
460 }
461
462 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
463 {
464 struct tcp_sock *tp = tcp_sk(sk);
465 int answ;
466
467 switch (cmd) {
468 case SIOCINQ:
469 if (sk->sk_state == TCP_LISTEN)
470 return -EINVAL;
471
472 lock_sock(sk);
473 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
474 answ = 0;
475 else if (sock_flag(sk, SOCK_URGINLINE) ||
476 !tp->urg_data ||
477 before(tp->urg_seq, tp->copied_seq) ||
478 !before(tp->urg_seq, tp->rcv_nxt)) {
479 struct sk_buff *skb;
480
481 answ = tp->rcv_nxt - tp->copied_seq;
482
483 /* Subtract 1, if FIN is in queue. */
484 skb = skb_peek_tail(&sk->sk_receive_queue);
485 if (answ && skb)
486 answ -= tcp_hdr(skb)->fin;
487 } else
488 answ = tp->urg_seq - tp->copied_seq;
489 release_sock(sk);
490 break;
491 case SIOCATMARK:
492 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
493 break;
494 case SIOCOUTQ:
495 if (sk->sk_state == TCP_LISTEN)
496 return -EINVAL;
497
498 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
499 answ = 0;
500 else
501 answ = tp->write_seq - tp->snd_una;
502 break;
503 default:
504 return -ENOIOCTLCMD;
505 }
506
507 return put_user(answ, (int __user *)arg);
508 }
509
510 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
511 {
512 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
513 tp->pushed_seq = tp->write_seq;
514 }
515
516 static inline int forced_push(struct tcp_sock *tp)
517 {
518 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
519 }
520
521 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
522 {
523 struct tcp_sock *tp = tcp_sk(sk);
524 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
525
526 skb->csum = 0;
527 tcb->seq = tcb->end_seq = tp->write_seq;
528 tcb->flags = TCPCB_FLAG_ACK;
529 tcb->sacked = 0;
530 skb_header_release(skb);
531 tcp_add_write_queue_tail(sk, skb);
532 sk->sk_wmem_queued += skb->truesize;
533 sk_mem_charge(sk, skb->truesize);
534 if (tp->nonagle & TCP_NAGLE_PUSH)
535 tp->nonagle &= ~TCP_NAGLE_PUSH;
536 }
537
538 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
539 struct sk_buff *skb)
540 {
541 if (flags & MSG_OOB)
542 tp->snd_up = tp->write_seq;
543 }
544
545 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
546 int nonagle)
547 {
548 struct tcp_sock *tp = tcp_sk(sk);
549
550 if (tcp_send_head(sk)) {
551 struct sk_buff *skb = tcp_write_queue_tail(sk);
552 if (!(flags & MSG_MORE) || forced_push(tp))
553 tcp_mark_push(tp, skb);
554 tcp_mark_urg(tp, flags, skb);
555 __tcp_push_pending_frames(sk, mss_now,
556 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
557 }
558 }
559
560 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
561 unsigned int offset, size_t len)
562 {
563 struct tcp_splice_state *tss = rd_desc->arg.data;
564 int ret;
565
566 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
567 tss->flags);
568 if (ret > 0)
569 rd_desc->count -= ret;
570 return ret;
571 }
572
573 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
574 {
575 /* Store TCP splice context information in read_descriptor_t. */
576 read_descriptor_t rd_desc = {
577 .arg.data = tss,
578 .count = tss->len,
579 };
580
581 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
582 }
583
584 /**
585 * tcp_splice_read - splice data from TCP socket to a pipe
586 * @sock: socket to splice from
587 * @ppos: position (not valid)
588 * @pipe: pipe to splice to
589 * @len: number of bytes to splice
590 * @flags: splice modifier flags
591 *
592 * Description:
593 * Will read pages from given socket and fill them into a pipe.
594 *
595 **/
596 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
597 struct pipe_inode_info *pipe, size_t len,
598 unsigned int flags)
599 {
600 struct sock *sk = sock->sk;
601 struct tcp_splice_state tss = {
602 .pipe = pipe,
603 .len = len,
604 .flags = flags,
605 };
606 long timeo;
607 ssize_t spliced;
608 int ret;
609
610 /*
611 * We can't seek on a socket input
612 */
613 if (unlikely(*ppos))
614 return -ESPIPE;
615
616 ret = spliced = 0;
617
618 lock_sock(sk);
619
620 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
621 while (tss.len) {
622 ret = __tcp_splice_read(sk, &tss);
623 if (ret < 0)
624 break;
625 else if (!ret) {
626 if (spliced)
627 break;
628 if (sock_flag(sk, SOCK_DONE))
629 break;
630 if (sk->sk_err) {
631 ret = sock_error(sk);
632 break;
633 }
634 if (sk->sk_shutdown & RCV_SHUTDOWN)
635 break;
636 if (sk->sk_state == TCP_CLOSE) {
637 /*
638 * This occurs when user tries to read
639 * from never connected socket.
640 */
641 if (!sock_flag(sk, SOCK_DONE))
642 ret = -ENOTCONN;
643 break;
644 }
645 if (!timeo) {
646 ret = -EAGAIN;
647 break;
648 }
649 sk_wait_data(sk, &timeo);
650 if (signal_pending(current)) {
651 ret = sock_intr_errno(timeo);
652 break;
653 }
654 continue;
655 }
656 tss.len -= ret;
657 spliced += ret;
658
659 if (!timeo)
660 break;
661 release_sock(sk);
662 lock_sock(sk);
663
664 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
665 (sk->sk_shutdown & RCV_SHUTDOWN) ||
666 signal_pending(current))
667 break;
668 }
669
670 release_sock(sk);
671
672 if (spliced)
673 return spliced;
674
675 return ret;
676 }
677
678 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
679 {
680 struct sk_buff *skb;
681
682 /* The TCP header must be at least 32-bit aligned. */
683 size = ALIGN(size, 4);
684
685 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
686 if (skb) {
687 if (sk_wmem_schedule(sk, skb->truesize)) {
688 /*
689 * Make sure that we have exactly size bytes
690 * available to the caller, no more, no less.
691 */
692 skb_reserve(skb, skb_tailroom(skb) - size);
693 return skb;
694 }
695 __kfree_skb(skb);
696 } else {
697 sk->sk_prot->enter_memory_pressure(sk);
698 sk_stream_moderate_sndbuf(sk);
699 }
700 return NULL;
701 }
702
703 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
704 int large_allowed)
705 {
706 struct tcp_sock *tp = tcp_sk(sk);
707 u32 xmit_size_goal, old_size_goal;
708
709 xmit_size_goal = mss_now;
710
711 if (large_allowed && sk_can_gso(sk)) {
712 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
713 inet_csk(sk)->icsk_af_ops->net_header_len -
714 inet_csk(sk)->icsk_ext_hdr_len -
715 tp->tcp_header_len);
716
717 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
718
719 /* We try hard to avoid divides here */
720 old_size_goal = tp->xmit_size_goal_segs * mss_now;
721
722 if (likely(old_size_goal <= xmit_size_goal &&
723 old_size_goal + mss_now > xmit_size_goal)) {
724 xmit_size_goal = old_size_goal;
725 } else {
726 tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
727 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
728 }
729 }
730
731 return max(xmit_size_goal, mss_now);
732 }
733
734 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
735 {
736 int mss_now;
737
738 mss_now = tcp_current_mss(sk);
739 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
740
741 return mss_now;
742 }
743
744 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
745 size_t psize, int flags)
746 {
747 struct tcp_sock *tp = tcp_sk(sk);
748 int mss_now, size_goal;
749 int err;
750 ssize_t copied;
751 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
752
753 /* Wait for a connection to finish. */
754 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
755 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
756 goto out_err;
757
758 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
759
760 mss_now = tcp_send_mss(sk, &size_goal, flags);
761 copied = 0;
762
763 err = -EPIPE;
764 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
765 goto out_err;
766
767 while (psize > 0) {
768 struct sk_buff *skb = tcp_write_queue_tail(sk);
769 struct page *page = pages[poffset / PAGE_SIZE];
770 int copy, i, can_coalesce;
771 int offset = poffset % PAGE_SIZE;
772 int size = min_t(size_t, psize, PAGE_SIZE - offset);
773
774 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
775 new_segment:
776 if (!sk_stream_memory_free(sk))
777 goto wait_for_sndbuf;
778
779 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
780 if (!skb)
781 goto wait_for_memory;
782
783 skb_entail(sk, skb);
784 copy = size_goal;
785 }
786
787 if (copy > size)
788 copy = size;
789
790 i = skb_shinfo(skb)->nr_frags;
791 can_coalesce = skb_can_coalesce(skb, i, page, offset);
792 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
793 tcp_mark_push(tp, skb);
794 goto new_segment;
795 }
796 if (!sk_wmem_schedule(sk, copy))
797 goto wait_for_memory;
798
799 if (can_coalesce) {
800 skb_shinfo(skb)->frags[i - 1].size += copy;
801 } else {
802 get_page(page);
803 skb_fill_page_desc(skb, i, page, offset, copy);
804 }
805
806 skb->len += copy;
807 skb->data_len += copy;
808 skb->truesize += copy;
809 sk->sk_wmem_queued += copy;
810 sk_mem_charge(sk, copy);
811 skb->ip_summed = CHECKSUM_PARTIAL;
812 tp->write_seq += copy;
813 TCP_SKB_CB(skb)->end_seq += copy;
814 skb_shinfo(skb)->gso_segs = 0;
815
816 if (!copied)
817 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
818
819 copied += copy;
820 poffset += copy;
821 if (!(psize -= copy))
822 goto out;
823
824 if (skb->len < size_goal || (flags & MSG_OOB))
825 continue;
826
827 if (forced_push(tp)) {
828 tcp_mark_push(tp, skb);
829 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
830 } else if (skb == tcp_send_head(sk))
831 tcp_push_one(sk, mss_now);
832 continue;
833
834 wait_for_sndbuf:
835 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
836 wait_for_memory:
837 if (copied)
838 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
839
840 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
841 goto do_error;
842
843 mss_now = tcp_send_mss(sk, &size_goal, flags);
844 }
845
846 out:
847 if (copied)
848 tcp_push(sk, flags, mss_now, tp->nonagle);
849 return copied;
850
851 do_error:
852 if (copied)
853 goto out;
854 out_err:
855 return sk_stream_error(sk, flags, err);
856 }
857
858 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
859 size_t size, int flags)
860 {
861 ssize_t res;
862 struct sock *sk = sock->sk;
863
864 if (!(sk->sk_route_caps & NETIF_F_SG) ||
865 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
866 return sock_no_sendpage(sock, page, offset, size, flags);
867
868 lock_sock(sk);
869 TCP_CHECK_TIMER(sk);
870 res = do_tcp_sendpages(sk, &page, offset, size, flags);
871 TCP_CHECK_TIMER(sk);
872 release_sock(sk);
873 return res;
874 }
875
876 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
877 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
878
879 static inline int select_size(struct sock *sk)
880 {
881 struct tcp_sock *tp = tcp_sk(sk);
882 int tmp = tp->mss_cache;
883
884 if (sk->sk_route_caps & NETIF_F_SG) {
885 if (sk_can_gso(sk))
886 tmp = 0;
887 else {
888 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
889
890 if (tmp >= pgbreak &&
891 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
892 tmp = pgbreak;
893 }
894 }
895
896 return tmp;
897 }
898
899 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
900 size_t size)
901 {
902 struct sock *sk = sock->sk;
903 struct iovec *iov;
904 struct tcp_sock *tp = tcp_sk(sk);
905 struct sk_buff *skb;
906 int iovlen, flags;
907 int mss_now, size_goal;
908 int err, copied;
909 long timeo;
910
911 lock_sock(sk);
912 TCP_CHECK_TIMER(sk);
913
914 flags = msg->msg_flags;
915 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
916
917 /* Wait for a connection to finish. */
918 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
919 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
920 goto out_err;
921
922 /* This should be in poll */
923 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
924
925 mss_now = tcp_send_mss(sk, &size_goal, flags);
926
927 /* Ok commence sending. */
928 iovlen = msg->msg_iovlen;
929 iov = msg->msg_iov;
930 copied = 0;
931
932 err = -EPIPE;
933 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
934 goto out_err;
935
936 while (--iovlen >= 0) {
937 int seglen = iov->iov_len;
938 unsigned char __user *from = iov->iov_base;
939
940 iov++;
941
942 while (seglen > 0) {
943 int copy = 0;
944 int max = size_goal;
945
946 skb = tcp_write_queue_tail(sk);
947 if (tcp_send_head(sk)) {
948 if (skb->ip_summed == CHECKSUM_NONE)
949 max = mss_now;
950 copy = max - skb->len;
951 }
952
953 if (copy <= 0) {
954 new_segment:
955 /* Allocate new segment. If the interface is SG,
956 * allocate skb fitting to single page.
957 */
958 if (!sk_stream_memory_free(sk))
959 goto wait_for_sndbuf;
960
961 skb = sk_stream_alloc_skb(sk, select_size(sk),
962 sk->sk_allocation);
963 if (!skb)
964 goto wait_for_memory;
965
966 /*
967 * Check whether we can use HW checksum.
968 */
969 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
970 skb->ip_summed = CHECKSUM_PARTIAL;
971
972 skb_entail(sk, skb);
973 copy = size_goal;
974 max = size_goal;
975 }
976
977 /* Try to append data to the end of skb. */
978 if (copy > seglen)
979 copy = seglen;
980
981 /* Where to copy to? */
982 if (skb_tailroom(skb) > 0) {
983 /* We have some space in skb head. Superb! */
984 if (copy > skb_tailroom(skb))
985 copy = skb_tailroom(skb);
986 if ((err = skb_add_data(skb, from, copy)) != 0)
987 goto do_fault;
988 } else {
989 int merge = 0;
990 int i = skb_shinfo(skb)->nr_frags;
991 struct page *page = TCP_PAGE(sk);
992 int off = TCP_OFF(sk);
993
994 if (skb_can_coalesce(skb, i, page, off) &&
995 off != PAGE_SIZE) {
996 /* We can extend the last page
997 * fragment. */
998 merge = 1;
999 } else if (i == MAX_SKB_FRAGS ||
1000 (!i &&
1001 !(sk->sk_route_caps & NETIF_F_SG))) {
1002 /* Need to add new fragment and cannot
1003 * do this because interface is non-SG,
1004 * or because all the page slots are
1005 * busy. */
1006 tcp_mark_push(tp, skb);
1007 goto new_segment;
1008 } else if (page) {
1009 if (off == PAGE_SIZE) {
1010 put_page(page);
1011 TCP_PAGE(sk) = page = NULL;
1012 off = 0;
1013 }
1014 } else
1015 off = 0;
1016
1017 if (copy > PAGE_SIZE - off)
1018 copy = PAGE_SIZE - off;
1019
1020 if (!sk_wmem_schedule(sk, copy))
1021 goto wait_for_memory;
1022
1023 if (!page) {
1024 /* Allocate new cache page. */
1025 if (!(page = sk_stream_alloc_page(sk)))
1026 goto wait_for_memory;
1027 }
1028
1029 /* Time to copy data. We are close to
1030 * the end! */
1031 err = skb_copy_to_page(sk, from, skb, page,
1032 off, copy);
1033 if (err) {
1034 /* If this page was new, give it to the
1035 * socket so it does not get leaked.
1036 */
1037 if (!TCP_PAGE(sk)) {
1038 TCP_PAGE(sk) = page;
1039 TCP_OFF(sk) = 0;
1040 }
1041 goto do_error;
1042 }
1043
1044 /* Update the skb. */
1045 if (merge) {
1046 skb_shinfo(skb)->frags[i - 1].size +=
1047 copy;
1048 } else {
1049 skb_fill_page_desc(skb, i, page, off, copy);
1050 if (TCP_PAGE(sk)) {
1051 get_page(page);
1052 } else if (off + copy < PAGE_SIZE) {
1053 get_page(page);
1054 TCP_PAGE(sk) = page;
1055 }
1056 }
1057
1058 TCP_OFF(sk) = off + copy;
1059 }
1060
1061 if (!copied)
1062 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
1063
1064 tp->write_seq += copy;
1065 TCP_SKB_CB(skb)->end_seq += copy;
1066 skb_shinfo(skb)->gso_segs = 0;
1067
1068 from += copy;
1069 copied += copy;
1070 if ((seglen -= copy) == 0 && iovlen == 0)
1071 goto out;
1072
1073 if (skb->len < max || (flags & MSG_OOB))
1074 continue;
1075
1076 if (forced_push(tp)) {
1077 tcp_mark_push(tp, skb);
1078 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1079 } else if (skb == tcp_send_head(sk))
1080 tcp_push_one(sk, mss_now);
1081 continue;
1082
1083 wait_for_sndbuf:
1084 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1085 wait_for_memory:
1086 if (copied)
1087 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1088
1089 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1090 goto do_error;
1091
1092 mss_now = tcp_send_mss(sk, &size_goal, flags);
1093 }
1094 }
1095
1096 out:
1097 if (copied)
1098 tcp_push(sk, flags, mss_now, tp->nonagle);
1099 TCP_CHECK_TIMER(sk);
1100 release_sock(sk);
1101 return copied;
1102
1103 do_fault:
1104 if (!skb->len) {
1105 tcp_unlink_write_queue(skb, sk);
1106 /* It is the one place in all of TCP, except connection
1107 * reset, where we can be unlinking the send_head.
1108 */
1109 tcp_check_send_head(sk, skb);
1110 sk_wmem_free_skb(sk, skb);
1111 }
1112
1113 do_error:
1114 if (copied)
1115 goto out;
1116 out_err:
1117 err = sk_stream_error(sk, flags, err);
1118 TCP_CHECK_TIMER(sk);
1119 release_sock(sk);
1120 return err;
1121 }
1122
1123 /*
1124 * Handle reading urgent data. BSD has very simple semantics for
1125 * this, no blocking and very strange errors 8)
1126 */
1127
1128 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1129 {
1130 struct tcp_sock *tp = tcp_sk(sk);
1131
1132 /* No URG data to read. */
1133 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1134 tp->urg_data == TCP_URG_READ)
1135 return -EINVAL; /* Yes this is right ! */
1136
1137 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1138 return -ENOTCONN;
1139
1140 if (tp->urg_data & TCP_URG_VALID) {
1141 int err = 0;
1142 char c = tp->urg_data;
1143
1144 if (!(flags & MSG_PEEK))
1145 tp->urg_data = TCP_URG_READ;
1146
1147 /* Read urgent data. */
1148 msg->msg_flags |= MSG_OOB;
1149
1150 if (len > 0) {
1151 if (!(flags & MSG_TRUNC))
1152 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1153 len = 1;
1154 } else
1155 msg->msg_flags |= MSG_TRUNC;
1156
1157 return err ? -EFAULT : len;
1158 }
1159
1160 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1161 return 0;
1162
1163 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1164 * the available implementations agree in this case:
1165 * this call should never block, independent of the
1166 * blocking state of the socket.
1167 * Mike <pall@rz.uni-karlsruhe.de>
1168 */
1169 return -EAGAIN;
1170 }
1171
1172 /* Clean up the receive buffer for full frames taken by the user,
1173 * then send an ACK if necessary. COPIED is the number of bytes
1174 * tcp_recvmsg has given to the user so far, it speeds up the
1175 * calculation of whether or not we must ACK for the sake of
1176 * a window update.
1177 */
1178 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1179 {
1180 struct tcp_sock *tp = tcp_sk(sk);
1181 int time_to_ack = 0;
1182
1183 #if TCP_DEBUG
1184 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1185
1186 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1187 KERN_INFO "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1188 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1189 #endif
1190
1191 if (inet_csk_ack_scheduled(sk)) {
1192 const struct inet_connection_sock *icsk = inet_csk(sk);
1193 /* Delayed ACKs frequently hit locked sockets during bulk
1194 * receive. */
1195 if (icsk->icsk_ack.blocked ||
1196 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1197 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1198 /*
1199 * If this read emptied read buffer, we send ACK, if
1200 * connection is not bidirectional, user drained
1201 * receive buffer and there was a small segment
1202 * in queue.
1203 */
1204 (copied > 0 &&
1205 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1206 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1207 !icsk->icsk_ack.pingpong)) &&
1208 !atomic_read(&sk->sk_rmem_alloc)))
1209 time_to_ack = 1;
1210 }
1211
1212 /* We send an ACK if we can now advertise a non-zero window
1213 * which has been raised "significantly".
1214 *
1215 * Even if window raised up to infinity, do not send window open ACK
1216 * in states, where we will not receive more. It is useless.
1217 */
1218 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1219 __u32 rcv_window_now = tcp_receive_window(tp);
1220
1221 /* Optimize, __tcp_select_window() is not cheap. */
1222 if (2*rcv_window_now <= tp->window_clamp) {
1223 __u32 new_window = __tcp_select_window(sk);
1224
1225 /* Send ACK now, if this read freed lots of space
1226 * in our buffer. Certainly, new_window is new window.
1227 * We can advertise it now, if it is not less than current one.
1228 * "Lots" means "at least twice" here.
1229 */
1230 if (new_window && new_window >= 2 * rcv_window_now)
1231 time_to_ack = 1;
1232 }
1233 }
1234 if (time_to_ack)
1235 tcp_send_ack(sk);
1236 }
1237
1238 static void tcp_prequeue_process(struct sock *sk)
1239 {
1240 struct sk_buff *skb;
1241 struct tcp_sock *tp = tcp_sk(sk);
1242
1243 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1244
1245 /* RX process wants to run with disabled BHs, though it is not
1246 * necessary */
1247 local_bh_disable();
1248 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1249 sk_backlog_rcv(sk, skb);
1250 local_bh_enable();
1251
1252 /* Clear memory counter. */
1253 tp->ucopy.memory = 0;
1254 }
1255
1256 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1257 {
1258 struct sk_buff *skb;
1259 u32 offset;
1260
1261 skb_queue_walk(&sk->sk_receive_queue, skb) {
1262 offset = seq - TCP_SKB_CB(skb)->seq;
1263 if (tcp_hdr(skb)->syn)
1264 offset--;
1265 if (offset < skb->len || tcp_hdr(skb)->fin) {
1266 *off = offset;
1267 return skb;
1268 }
1269 }
1270 return NULL;
1271 }
1272
1273 /*
1274 * This routine provides an alternative to tcp_recvmsg() for routines
1275 * that would like to handle copying from skbuffs directly in 'sendfile'
1276 * fashion.
1277 * Note:
1278 * - It is assumed that the socket was locked by the caller.
1279 * - The routine does not block.
1280 * - At present, there is no support for reading OOB data
1281 * or for 'peeking' the socket using this routine
1282 * (although both would be easy to implement).
1283 */
1284 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1285 sk_read_actor_t recv_actor)
1286 {
1287 struct sk_buff *skb;
1288 struct tcp_sock *tp = tcp_sk(sk);
1289 u32 seq = tp->copied_seq;
1290 u32 offset;
1291 int copied = 0;
1292
1293 if (sk->sk_state == TCP_LISTEN)
1294 return -ENOTCONN;
1295 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1296 if (offset < skb->len) {
1297 int used;
1298 size_t len;
1299
1300 len = skb->len - offset;
1301 /* Stop reading if we hit a patch of urgent data */
1302 if (tp->urg_data) {
1303 u32 urg_offset = tp->urg_seq - seq;
1304 if (urg_offset < len)
1305 len = urg_offset;
1306 if (!len)
1307 break;
1308 }
1309 used = recv_actor(desc, skb, offset, len);
1310 if (used < 0) {
1311 if (!copied)
1312 copied = used;
1313 break;
1314 } else if (used <= len) {
1315 seq += used;
1316 copied += used;
1317 offset += used;
1318 }
1319 /*
1320 * If recv_actor drops the lock (e.g. TCP splice
1321 * receive) the skb pointer might be invalid when
1322 * getting here: tcp_collapse might have deleted it
1323 * while aggregating skbs from the socket queue.
1324 */
1325 skb = tcp_recv_skb(sk, seq-1, &offset);
1326 if (!skb || (offset+1 != skb->len))
1327 break;
1328 }
1329 if (tcp_hdr(skb)->fin) {
1330 sk_eat_skb(sk, skb, 0);
1331 ++seq;
1332 break;
1333 }
1334 sk_eat_skb(sk, skb, 0);
1335 if (!desc->count)
1336 break;
1337 }
1338 tp->copied_seq = seq;
1339
1340 tcp_rcv_space_adjust(sk);
1341
1342 /* Clean up data we have read: This will do ACK frames. */
1343 if (copied > 0)
1344 tcp_cleanup_rbuf(sk, copied);
1345 return copied;
1346 }
1347
1348 /*
1349 * This routine copies from a sock struct into the user buffer.
1350 *
1351 * Technical note: in 2.3 we work on _locked_ socket, so that
1352 * tricks with *seq access order and skb->users are not required.
1353 * Probably, code can be easily improved even more.
1354 */
1355
1356 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1357 size_t len, int nonblock, int flags, int *addr_len)
1358 {
1359 struct tcp_sock *tp = tcp_sk(sk);
1360 int copied = 0;
1361 u32 peek_seq;
1362 u32 *seq;
1363 unsigned long used;
1364 int err;
1365 int target; /* Read at least this many bytes */
1366 long timeo;
1367 struct task_struct *user_recv = NULL;
1368 int copied_early = 0;
1369 struct sk_buff *skb;
1370 u32 urg_hole = 0;
1371
1372 lock_sock(sk);
1373
1374 TCP_CHECK_TIMER(sk);
1375
1376 err = -ENOTCONN;
1377 if (sk->sk_state == TCP_LISTEN)
1378 goto out;
1379
1380 timeo = sock_rcvtimeo(sk, nonblock);
1381
1382 /* Urgent data needs to be handled specially. */
1383 if (flags & MSG_OOB)
1384 goto recv_urg;
1385
1386 seq = &tp->copied_seq;
1387 if (flags & MSG_PEEK) {
1388 peek_seq = tp->copied_seq;
1389 seq = &peek_seq;
1390 }
1391
1392 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1393
1394 #ifdef CONFIG_NET_DMA
1395 tp->ucopy.dma_chan = NULL;
1396 preempt_disable();
1397 skb = skb_peek_tail(&sk->sk_receive_queue);
1398 {
1399 int available = 0;
1400
1401 if (skb)
1402 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1403 if ((available < target) &&
1404 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1405 !sysctl_tcp_low_latency &&
1406 dma_find_channel(DMA_MEMCPY)) {
1407 preempt_enable_no_resched();
1408 tp->ucopy.pinned_list =
1409 dma_pin_iovec_pages(msg->msg_iov, len);
1410 } else {
1411 preempt_enable_no_resched();
1412 }
1413 }
1414 #endif
1415
1416 do {
1417 u32 offset;
1418
1419 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1420 if (tp->urg_data && tp->urg_seq == *seq) {
1421 if (copied)
1422 break;
1423 if (signal_pending(current)) {
1424 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1425 break;
1426 }
1427 }
1428
1429 /* Next get a buffer. */
1430
1431 skb_queue_walk(&sk->sk_receive_queue, skb) {
1432 /* Now that we have two receive queues this
1433 * shouldn't happen.
1434 */
1435 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1436 KERN_INFO "recvmsg bug: copied %X "
1437 "seq %X rcvnxt %X fl %X\n", *seq,
1438 TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1439 flags))
1440 break;
1441
1442 offset = *seq - TCP_SKB_CB(skb)->seq;
1443 if (tcp_hdr(skb)->syn)
1444 offset--;
1445 if (offset < skb->len)
1446 goto found_ok_skb;
1447 if (tcp_hdr(skb)->fin)
1448 goto found_fin_ok;
1449 WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "
1450 "copied %X seq %X rcvnxt %X fl %X\n",
1451 *seq, TCP_SKB_CB(skb)->seq,
1452 tp->rcv_nxt, flags);
1453 }
1454
1455 /* Well, if we have backlog, try to process it now yet. */
1456
1457 if (copied >= target && !sk->sk_backlog.tail)
1458 break;
1459
1460 if (copied) {
1461 if (sk->sk_err ||
1462 sk->sk_state == TCP_CLOSE ||
1463 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1464 !timeo ||
1465 signal_pending(current))
1466 break;
1467 } else {
1468 if (sock_flag(sk, SOCK_DONE))
1469 break;
1470
1471 if (sk->sk_err) {
1472 copied = sock_error(sk);
1473 break;
1474 }
1475
1476 if (sk->sk_shutdown & RCV_SHUTDOWN)
1477 break;
1478
1479 if (sk->sk_state == TCP_CLOSE) {
1480 if (!sock_flag(sk, SOCK_DONE)) {
1481 /* This occurs when user tries to read
1482 * from never connected socket.
1483 */
1484 copied = -ENOTCONN;
1485 break;
1486 }
1487 break;
1488 }
1489
1490 if (!timeo) {
1491 copied = -EAGAIN;
1492 break;
1493 }
1494
1495 if (signal_pending(current)) {
1496 copied = sock_intr_errno(timeo);
1497 break;
1498 }
1499 }
1500
1501 tcp_cleanup_rbuf(sk, copied);
1502
1503 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1504 /* Install new reader */
1505 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1506 user_recv = current;
1507 tp->ucopy.task = user_recv;
1508 tp->ucopy.iov = msg->msg_iov;
1509 }
1510
1511 tp->ucopy.len = len;
1512
1513 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1514 !(flags & (MSG_PEEK | MSG_TRUNC)));
1515
1516 /* Ugly... If prequeue is not empty, we have to
1517 * process it before releasing socket, otherwise
1518 * order will be broken at second iteration.
1519 * More elegant solution is required!!!
1520 *
1521 * Look: we have the following (pseudo)queues:
1522 *
1523 * 1. packets in flight
1524 * 2. backlog
1525 * 3. prequeue
1526 * 4. receive_queue
1527 *
1528 * Each queue can be processed only if the next ones
1529 * are empty. At this point we have empty receive_queue.
1530 * But prequeue _can_ be not empty after 2nd iteration,
1531 * when we jumped to start of loop because backlog
1532 * processing added something to receive_queue.
1533 * We cannot release_sock(), because backlog contains
1534 * packets arrived _after_ prequeued ones.
1535 *
1536 * Shortly, algorithm is clear --- to process all
1537 * the queues in order. We could make it more directly,
1538 * requeueing packets from backlog to prequeue, if
1539 * is not empty. It is more elegant, but eats cycles,
1540 * unfortunately.
1541 */
1542 if (!skb_queue_empty(&tp->ucopy.prequeue))
1543 goto do_prequeue;
1544
1545 /* __ Set realtime policy in scheduler __ */
1546 }
1547
1548 if (copied >= target) {
1549 /* Do not sleep, just process backlog. */
1550 release_sock(sk);
1551 lock_sock(sk);
1552 } else
1553 sk_wait_data(sk, &timeo);
1554
1555 #ifdef CONFIG_NET_DMA
1556 tp->ucopy.wakeup = 0;
1557 #endif
1558
1559 if (user_recv) {
1560 int chunk;
1561
1562 /* __ Restore normal policy in scheduler __ */
1563
1564 if ((chunk = len - tp->ucopy.len) != 0) {
1565 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1566 len -= chunk;
1567 copied += chunk;
1568 }
1569
1570 if (tp->rcv_nxt == tp->copied_seq &&
1571 !skb_queue_empty(&tp->ucopy.prequeue)) {
1572 do_prequeue:
1573 tcp_prequeue_process(sk);
1574
1575 if ((chunk = len - tp->ucopy.len) != 0) {
1576 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1577 len -= chunk;
1578 copied += chunk;
1579 }
1580 }
1581 }
1582 if ((flags & MSG_PEEK) &&
1583 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1584 if (net_ratelimit())
1585 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1586 current->comm, task_pid_nr(current));
1587 peek_seq = tp->copied_seq;
1588 }
1589 continue;
1590
1591 found_ok_skb:
1592 /* Ok so how much can we use? */
1593 used = skb->len - offset;
1594 if (len < used)
1595 used = len;
1596
1597 /* Do we have urgent data here? */
1598 if (tp->urg_data) {
1599 u32 urg_offset = tp->urg_seq - *seq;
1600 if (urg_offset < used) {
1601 if (!urg_offset) {
1602 if (!sock_flag(sk, SOCK_URGINLINE)) {
1603 ++*seq;
1604 urg_hole++;
1605 offset++;
1606 used--;
1607 if (!used)
1608 goto skip_copy;
1609 }
1610 } else
1611 used = urg_offset;
1612 }
1613 }
1614
1615 if (!(flags & MSG_TRUNC)) {
1616 #ifdef CONFIG_NET_DMA
1617 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1618 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1619
1620 if (tp->ucopy.dma_chan) {
1621 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1622 tp->ucopy.dma_chan, skb, offset,
1623 msg->msg_iov, used,
1624 tp->ucopy.pinned_list);
1625
1626 if (tp->ucopy.dma_cookie < 0) {
1627
1628 printk(KERN_ALERT "dma_cookie < 0\n");
1629
1630 /* Exception. Bailout! */
1631 if (!copied)
1632 copied = -EFAULT;
1633 break;
1634 }
1635 if ((offset + used) == skb->len)
1636 copied_early = 1;
1637
1638 } else
1639 #endif
1640 {
1641 err = skb_copy_datagram_iovec(skb, offset,
1642 msg->msg_iov, used);
1643 if (err) {
1644 /* Exception. Bailout! */
1645 if (!copied)
1646 copied = -EFAULT;
1647 break;
1648 }
1649 }
1650 }
1651
1652 *seq += used;
1653 copied += used;
1654 len -= used;
1655
1656 tcp_rcv_space_adjust(sk);
1657
1658 skip_copy:
1659 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1660 tp->urg_data = 0;
1661 tcp_fast_path_check(sk);
1662 }
1663 if (used + offset < skb->len)
1664 continue;
1665
1666 if (tcp_hdr(skb)->fin)
1667 goto found_fin_ok;
1668 if (!(flags & MSG_PEEK)) {
1669 sk_eat_skb(sk, skb, copied_early);
1670 copied_early = 0;
1671 }
1672 continue;
1673
1674 found_fin_ok:
1675 /* Process the FIN. */
1676 ++*seq;
1677 if (!(flags & MSG_PEEK)) {
1678 sk_eat_skb(sk, skb, copied_early);
1679 copied_early = 0;
1680 }
1681 break;
1682 } while (len > 0);
1683
1684 if (user_recv) {
1685 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1686 int chunk;
1687
1688 tp->ucopy.len = copied > 0 ? len : 0;
1689
1690 tcp_prequeue_process(sk);
1691
1692 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1693 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1694 len -= chunk;
1695 copied += chunk;
1696 }
1697 }
1698
1699 tp->ucopy.task = NULL;
1700 tp->ucopy.len = 0;
1701 }
1702
1703 #ifdef CONFIG_NET_DMA
1704 if (tp->ucopy.dma_chan) {
1705 dma_cookie_t done, used;
1706
1707 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1708
1709 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1710 tp->ucopy.dma_cookie, &done,
1711 &used) == DMA_IN_PROGRESS) {
1712 /* do partial cleanup of sk_async_wait_queue */
1713 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1714 (dma_async_is_complete(skb->dma_cookie, done,
1715 used) == DMA_SUCCESS)) {
1716 __skb_dequeue(&sk->sk_async_wait_queue);
1717 kfree_skb(skb);
1718 }
1719 }
1720
1721 /* Safe to free early-copied skbs now */
1722 __skb_queue_purge(&sk->sk_async_wait_queue);
1723 tp->ucopy.dma_chan = NULL;
1724 }
1725 if (tp->ucopy.pinned_list) {
1726 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1727 tp->ucopy.pinned_list = NULL;
1728 }
1729 #endif
1730
1731 /* According to UNIX98, msg_name/msg_namelen are ignored
1732 * on connected socket. I was just happy when found this 8) --ANK
1733 */
1734
1735 /* Clean up data we have read: This will do ACK frames. */
1736 tcp_cleanup_rbuf(sk, copied);
1737
1738 TCP_CHECK_TIMER(sk);
1739 release_sock(sk);
1740 return copied;
1741
1742 out:
1743 TCP_CHECK_TIMER(sk);
1744 release_sock(sk);
1745 return err;
1746
1747 recv_urg:
1748 err = tcp_recv_urg(sk, msg, len, flags);
1749 goto out;
1750 }
1751
1752 void tcp_set_state(struct sock *sk, int state)
1753 {
1754 int oldstate = sk->sk_state;
1755
1756 switch (state) {
1757 case TCP_ESTABLISHED:
1758 if (oldstate != TCP_ESTABLISHED)
1759 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1760 break;
1761
1762 case TCP_CLOSE:
1763 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1764 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1765
1766 sk->sk_prot->unhash(sk);
1767 if (inet_csk(sk)->icsk_bind_hash &&
1768 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1769 inet_put_port(sk);
1770 /* fall through */
1771 default:
1772 if (oldstate == TCP_ESTABLISHED)
1773 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1774 }
1775
1776 /* Change state AFTER socket is unhashed to avoid closed
1777 * socket sitting in hash tables.
1778 */
1779 sk->sk_state = state;
1780
1781 #ifdef STATE_TRACE
1782 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1783 #endif
1784 }
1785 EXPORT_SYMBOL_GPL(tcp_set_state);
1786
1787 /*
1788 * State processing on a close. This implements the state shift for
1789 * sending our FIN frame. Note that we only send a FIN for some
1790 * states. A shutdown() may have already sent the FIN, or we may be
1791 * closed.
1792 */
1793
1794 static const unsigned char new_state[16] = {
1795 /* current state: new state: action: */
1796 /* (Invalid) */ TCP_CLOSE,
1797 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1798 /* TCP_SYN_SENT */ TCP_CLOSE,
1799 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1800 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1801 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1802 /* TCP_TIME_WAIT */ TCP_CLOSE,
1803 /* TCP_CLOSE */ TCP_CLOSE,
1804 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1805 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1806 /* TCP_LISTEN */ TCP_CLOSE,
1807 /* TCP_CLOSING */ TCP_CLOSING,
1808 };
1809
1810 static int tcp_close_state(struct sock *sk)
1811 {
1812 int next = (int)new_state[sk->sk_state];
1813 int ns = next & TCP_STATE_MASK;
1814
1815 tcp_set_state(sk, ns);
1816
1817 return next & TCP_ACTION_FIN;
1818 }
1819
1820 /*
1821 * Shutdown the sending side of a connection. Much like close except
1822 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1823 */
1824
1825 void tcp_shutdown(struct sock *sk, int how)
1826 {
1827 /* We need to grab some memory, and put together a FIN,
1828 * and then put it into the queue to be sent.
1829 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1830 */
1831 if (!(how & SEND_SHUTDOWN))
1832 return;
1833
1834 /* If we've already sent a FIN, or it's a closed state, skip this. */
1835 if ((1 << sk->sk_state) &
1836 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1837 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1838 /* Clear out any half completed packets. FIN if needed. */
1839 if (tcp_close_state(sk))
1840 tcp_send_fin(sk);
1841 }
1842 }
1843
1844 void tcp_close(struct sock *sk, long timeout)
1845 {
1846 struct sk_buff *skb;
1847 int data_was_unread = 0;
1848 int state;
1849
1850 lock_sock(sk);
1851 sk->sk_shutdown = SHUTDOWN_MASK;
1852
1853 if (sk->sk_state == TCP_LISTEN) {
1854 tcp_set_state(sk, TCP_CLOSE);
1855
1856 /* Special case. */
1857 inet_csk_listen_stop(sk);
1858
1859 goto adjudge_to_death;
1860 }
1861
1862 /* We need to flush the recv. buffs. We do this only on the
1863 * descriptor close, not protocol-sourced closes, because the
1864 * reader process may not have drained the data yet!
1865 */
1866 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1867 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1868 tcp_hdr(skb)->fin;
1869 data_was_unread += len;
1870 __kfree_skb(skb);
1871 }
1872
1873 sk_mem_reclaim(sk);
1874
1875 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1876 * data was lost. To witness the awful effects of the old behavior of
1877 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1878 * GET in an FTP client, suspend the process, wait for the client to
1879 * advertise a zero window, then kill -9 the FTP client, wheee...
1880 * Note: timeout is always zero in such a case.
1881 */
1882 if (data_was_unread) {
1883 /* Unread data was tossed, zap the connection. */
1884 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1885 tcp_set_state(sk, TCP_CLOSE);
1886 tcp_send_active_reset(sk, sk->sk_allocation);
1887 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1888 /* Check zero linger _after_ checking for unread data. */
1889 sk->sk_prot->disconnect(sk, 0);
1890 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1891 } else if (tcp_close_state(sk)) {
1892 /* We FIN if the application ate all the data before
1893 * zapping the connection.
1894 */
1895
1896 /* RED-PEN. Formally speaking, we have broken TCP state
1897 * machine. State transitions:
1898 *
1899 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1900 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1901 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1902 *
1903 * are legal only when FIN has been sent (i.e. in window),
1904 * rather than queued out of window. Purists blame.
1905 *
1906 * F.e. "RFC state" is ESTABLISHED,
1907 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1908 *
1909 * The visible declinations are that sometimes
1910 * we enter time-wait state, when it is not required really
1911 * (harmless), do not send active resets, when they are
1912 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1913 * they look as CLOSING or LAST_ACK for Linux)
1914 * Probably, I missed some more holelets.
1915 * --ANK
1916 */
1917 tcp_send_fin(sk);
1918 }
1919
1920 sk_stream_wait_close(sk, timeout);
1921
1922 adjudge_to_death:
1923 state = sk->sk_state;
1924 sock_hold(sk);
1925 sock_orphan(sk);
1926
1927 /* It is the last release_sock in its life. It will remove backlog. */
1928 release_sock(sk);
1929
1930
1931 /* Now socket is owned by kernel and we acquire BH lock
1932 to finish close. No need to check for user refs.
1933 */
1934 local_bh_disable();
1935 bh_lock_sock(sk);
1936 WARN_ON(sock_owned_by_user(sk));
1937
1938 percpu_counter_inc(sk->sk_prot->orphan_count);
1939
1940 /* Have we already been destroyed by a softirq or backlog? */
1941 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1942 goto out;
1943
1944 /* This is a (useful) BSD violating of the RFC. There is a
1945 * problem with TCP as specified in that the other end could
1946 * keep a socket open forever with no application left this end.
1947 * We use a 3 minute timeout (about the same as BSD) then kill
1948 * our end. If they send after that then tough - BUT: long enough
1949 * that we won't make the old 4*rto = almost no time - whoops
1950 * reset mistake.
1951 *
1952 * Nope, it was not mistake. It is really desired behaviour
1953 * f.e. on http servers, when such sockets are useless, but
1954 * consume significant resources. Let's do it with special
1955 * linger2 option. --ANK
1956 */
1957
1958 if (sk->sk_state == TCP_FIN_WAIT2) {
1959 struct tcp_sock *tp = tcp_sk(sk);
1960 if (tp->linger2 < 0) {
1961 tcp_set_state(sk, TCP_CLOSE);
1962 tcp_send_active_reset(sk, GFP_ATOMIC);
1963 NET_INC_STATS_BH(sock_net(sk),
1964 LINUX_MIB_TCPABORTONLINGER);
1965 } else {
1966 const int tmo = tcp_fin_time(sk);
1967
1968 if (tmo > TCP_TIMEWAIT_LEN) {
1969 inet_csk_reset_keepalive_timer(sk,
1970 tmo - TCP_TIMEWAIT_LEN);
1971 } else {
1972 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1973 goto out;
1974 }
1975 }
1976 }
1977 if (sk->sk_state != TCP_CLOSE) {
1978 int orphan_count = percpu_counter_read_positive(
1979 sk->sk_prot->orphan_count);
1980
1981 sk_mem_reclaim(sk);
1982 if (tcp_too_many_orphans(sk, orphan_count)) {
1983 if (net_ratelimit())
1984 printk(KERN_INFO "TCP: too many of orphaned "
1985 "sockets\n");
1986 tcp_set_state(sk, TCP_CLOSE);
1987 tcp_send_active_reset(sk, GFP_ATOMIC);
1988 NET_INC_STATS_BH(sock_net(sk),
1989 LINUX_MIB_TCPABORTONMEMORY);
1990 }
1991 }
1992
1993 if (sk->sk_state == TCP_CLOSE)
1994 inet_csk_destroy_sock(sk);
1995 /* Otherwise, socket is reprieved until protocol close. */
1996
1997 out:
1998 bh_unlock_sock(sk);
1999 local_bh_enable();
2000 sock_put(sk);
2001 }
2002
2003 /* These states need RST on ABORT according to RFC793 */
2004
2005 static inline int tcp_need_reset(int state)
2006 {
2007 return (1 << state) &
2008 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2009 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2010 }
2011
2012 int tcp_disconnect(struct sock *sk, int flags)
2013 {
2014 struct inet_sock *inet = inet_sk(sk);
2015 struct inet_connection_sock *icsk = inet_csk(sk);
2016 struct tcp_sock *tp = tcp_sk(sk);
2017 int err = 0;
2018 int old_state = sk->sk_state;
2019
2020 if (old_state != TCP_CLOSE)
2021 tcp_set_state(sk, TCP_CLOSE);
2022
2023 /* ABORT function of RFC793 */
2024 if (old_state == TCP_LISTEN) {
2025 inet_csk_listen_stop(sk);
2026 } else if (tcp_need_reset(old_state) ||
2027 (tp->snd_nxt != tp->write_seq &&
2028 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2029 /* The last check adjusts for discrepancy of Linux wrt. RFC
2030 * states
2031 */
2032 tcp_send_active_reset(sk, gfp_any());
2033 sk->sk_err = ECONNRESET;
2034 } else if (old_state == TCP_SYN_SENT)
2035 sk->sk_err = ECONNRESET;
2036
2037 tcp_clear_xmit_timers(sk);
2038 __skb_queue_purge(&sk->sk_receive_queue);
2039 tcp_write_queue_purge(sk);
2040 __skb_queue_purge(&tp->out_of_order_queue);
2041 #ifdef CONFIG_NET_DMA
2042 __skb_queue_purge(&sk->sk_async_wait_queue);
2043 #endif
2044
2045 inet->dport = 0;
2046
2047 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2048 inet_reset_saddr(sk);
2049
2050 sk->sk_shutdown = 0;
2051 sock_reset_flag(sk, SOCK_DONE);
2052 tp->srtt = 0;
2053 if ((tp->write_seq += tp->max_window + 2) == 0)
2054 tp->write_seq = 1;
2055 icsk->icsk_backoff = 0;
2056 tp->snd_cwnd = 2;
2057 icsk->icsk_probes_out = 0;
2058 tp->packets_out = 0;
2059 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2060 tp->snd_cwnd_cnt = 0;
2061 tp->bytes_acked = 0;
2062 tcp_set_ca_state(sk, TCP_CA_Open);
2063 tcp_clear_retrans(tp);
2064 inet_csk_delack_init(sk);
2065 tcp_init_send_head(sk);
2066 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2067 __sk_dst_reset(sk);
2068
2069 WARN_ON(inet->num && !icsk->icsk_bind_hash);
2070
2071 sk->sk_error_report(sk);
2072 return err;
2073 }
2074
2075 /*
2076 * Socket option code for TCP.
2077 */
2078 static int do_tcp_setsockopt(struct sock *sk, int level,
2079 int optname, char __user *optval, unsigned int optlen)
2080 {
2081 struct tcp_sock *tp = tcp_sk(sk);
2082 struct inet_connection_sock *icsk = inet_csk(sk);
2083 int val;
2084 int err = 0;
2085
2086 /* This is a string value all the others are int's */
2087 if (optname == TCP_CONGESTION) {
2088 char name[TCP_CA_NAME_MAX];
2089
2090 if (optlen < 1)
2091 return -EINVAL;
2092
2093 val = strncpy_from_user(name, optval,
2094 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2095 if (val < 0)
2096 return -EFAULT;
2097 name[val] = 0;
2098
2099 lock_sock(sk);
2100 err = tcp_set_congestion_control(sk, name);
2101 release_sock(sk);
2102 return err;
2103 }
2104
2105 if (optlen < sizeof(int))
2106 return -EINVAL;
2107
2108 if (get_user(val, (int __user *)optval))
2109 return -EFAULT;
2110
2111 lock_sock(sk);
2112
2113 switch (optname) {
2114 case TCP_MAXSEG:
2115 /* Values greater than interface MTU won't take effect. However
2116 * at the point when this call is done we typically don't yet
2117 * know which interface is going to be used */
2118 if (val < 8 || val > MAX_TCP_WINDOW) {
2119 err = -EINVAL;
2120 break;
2121 }
2122 tp->rx_opt.user_mss = val;
2123 break;
2124
2125 case TCP_NODELAY:
2126 if (val) {
2127 /* TCP_NODELAY is weaker than TCP_CORK, so that
2128 * this option on corked socket is remembered, but
2129 * it is not activated until cork is cleared.
2130 *
2131 * However, when TCP_NODELAY is set we make
2132 * an explicit push, which overrides even TCP_CORK
2133 * for currently queued segments.
2134 */
2135 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2136 tcp_push_pending_frames(sk);
2137 } else {
2138 tp->nonagle &= ~TCP_NAGLE_OFF;
2139 }
2140 break;
2141
2142 case TCP_CORK:
2143 /* When set indicates to always queue non-full frames.
2144 * Later the user clears this option and we transmit
2145 * any pending partial frames in the queue. This is
2146 * meant to be used alongside sendfile() to get properly
2147 * filled frames when the user (for example) must write
2148 * out headers with a write() call first and then use
2149 * sendfile to send out the data parts.
2150 *
2151 * TCP_CORK can be set together with TCP_NODELAY and it is
2152 * stronger than TCP_NODELAY.
2153 */
2154 if (val) {
2155 tp->nonagle |= TCP_NAGLE_CORK;
2156 } else {
2157 tp->nonagle &= ~TCP_NAGLE_CORK;
2158 if (tp->nonagle&TCP_NAGLE_OFF)
2159 tp->nonagle |= TCP_NAGLE_PUSH;
2160 tcp_push_pending_frames(sk);
2161 }
2162 break;
2163
2164 case TCP_KEEPIDLE:
2165 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2166 err = -EINVAL;
2167 else {
2168 tp->keepalive_time = val * HZ;
2169 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2170 !((1 << sk->sk_state) &
2171 (TCPF_CLOSE | TCPF_LISTEN))) {
2172 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2173 if (tp->keepalive_time > elapsed)
2174 elapsed = tp->keepalive_time - elapsed;
2175 else
2176 elapsed = 0;
2177 inet_csk_reset_keepalive_timer(sk, elapsed);
2178 }
2179 }
2180 break;
2181 case TCP_KEEPINTVL:
2182 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2183 err = -EINVAL;
2184 else
2185 tp->keepalive_intvl = val * HZ;
2186 break;
2187 case TCP_KEEPCNT:
2188 if (val < 1 || val > MAX_TCP_KEEPCNT)
2189 err = -EINVAL;
2190 else
2191 tp->keepalive_probes = val;
2192 break;
2193 case TCP_SYNCNT:
2194 if (val < 1 || val > MAX_TCP_SYNCNT)
2195 err = -EINVAL;
2196 else
2197 icsk->icsk_syn_retries = val;
2198 break;
2199
2200 case TCP_LINGER2:
2201 if (val < 0)
2202 tp->linger2 = -1;
2203 else if (val > sysctl_tcp_fin_timeout / HZ)
2204 tp->linger2 = 0;
2205 else
2206 tp->linger2 = val * HZ;
2207 break;
2208
2209 case TCP_DEFER_ACCEPT:
2210 /* Translate value in seconds to number of retransmits */
2211 icsk->icsk_accept_queue.rskq_defer_accept =
2212 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2213 TCP_RTO_MAX / HZ);
2214 break;
2215
2216 case TCP_WINDOW_CLAMP:
2217 if (!val) {
2218 if (sk->sk_state != TCP_CLOSE) {
2219 err = -EINVAL;
2220 break;
2221 }
2222 tp->window_clamp = 0;
2223 } else
2224 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2225 SOCK_MIN_RCVBUF / 2 : val;
2226 break;
2227
2228 case TCP_QUICKACK:
2229 if (!val) {
2230 icsk->icsk_ack.pingpong = 1;
2231 } else {
2232 icsk->icsk_ack.pingpong = 0;
2233 if ((1 << sk->sk_state) &
2234 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2235 inet_csk_ack_scheduled(sk)) {
2236 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2237 tcp_cleanup_rbuf(sk, 1);
2238 if (!(val & 1))
2239 icsk->icsk_ack.pingpong = 1;
2240 }
2241 }
2242 break;
2243
2244 #ifdef CONFIG_TCP_MD5SIG
2245 case TCP_MD5SIG:
2246 /* Read the IP->Key mappings from userspace */
2247 err = tp->af_specific->md5_parse(sk, optval, optlen);
2248 break;
2249 #endif
2250
2251 default:
2252 err = -ENOPROTOOPT;
2253 break;
2254 }
2255
2256 release_sock(sk);
2257 return err;
2258 }
2259
2260 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2261 unsigned int optlen)
2262 {
2263 struct inet_connection_sock *icsk = inet_csk(sk);
2264
2265 if (level != SOL_TCP)
2266 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2267 optval, optlen);
2268 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2269 }
2270
2271 #ifdef CONFIG_COMPAT
2272 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2273 char __user *optval, unsigned int optlen)
2274 {
2275 if (level != SOL_TCP)
2276 return inet_csk_compat_setsockopt(sk, level, optname,
2277 optval, optlen);
2278 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2279 }
2280
2281 EXPORT_SYMBOL(compat_tcp_setsockopt);
2282 #endif
2283
2284 /* Return information about state of tcp endpoint in API format. */
2285 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2286 {
2287 struct tcp_sock *tp = tcp_sk(sk);
2288 const struct inet_connection_sock *icsk = inet_csk(sk);
2289 u32 now = tcp_time_stamp;
2290
2291 memset(info, 0, sizeof(*info));
2292
2293 info->tcpi_state = sk->sk_state;
2294 info->tcpi_ca_state = icsk->icsk_ca_state;
2295 info->tcpi_retransmits = icsk->icsk_retransmits;
2296 info->tcpi_probes = icsk->icsk_probes_out;
2297 info->tcpi_backoff = icsk->icsk_backoff;
2298
2299 if (tp->rx_opt.tstamp_ok)
2300 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2301 if (tcp_is_sack(tp))
2302 info->tcpi_options |= TCPI_OPT_SACK;
2303 if (tp->rx_opt.wscale_ok) {
2304 info->tcpi_options |= TCPI_OPT_WSCALE;
2305 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2306 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2307 }
2308
2309 if (tp->ecn_flags&TCP_ECN_OK)
2310 info->tcpi_options |= TCPI_OPT_ECN;
2311
2312 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2313 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2314 info->tcpi_snd_mss = tp->mss_cache;
2315 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2316
2317 if (sk->sk_state == TCP_LISTEN) {
2318 info->tcpi_unacked = sk->sk_ack_backlog;
2319 info->tcpi_sacked = sk->sk_max_ack_backlog;
2320 } else {
2321 info->tcpi_unacked = tp->packets_out;
2322 info->tcpi_sacked = tp->sacked_out;
2323 }
2324 info->tcpi_lost = tp->lost_out;
2325 info->tcpi_retrans = tp->retrans_out;
2326 info->tcpi_fackets = tp->fackets_out;
2327
2328 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2329 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2330 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2331
2332 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2333 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2334 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2335 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2336 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2337 info->tcpi_snd_cwnd = tp->snd_cwnd;
2338 info->tcpi_advmss = tp->advmss;
2339 info->tcpi_reordering = tp->reordering;
2340
2341 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2342 info->tcpi_rcv_space = tp->rcvq_space.space;
2343
2344 info->tcpi_total_retrans = tp->total_retrans;
2345 }
2346
2347 EXPORT_SYMBOL_GPL(tcp_get_info);
2348
2349 static int do_tcp_getsockopt(struct sock *sk, int level,
2350 int optname, char __user *optval, int __user *optlen)
2351 {
2352 struct inet_connection_sock *icsk = inet_csk(sk);
2353 struct tcp_sock *tp = tcp_sk(sk);
2354 int val, len;
2355
2356 if (get_user(len, optlen))
2357 return -EFAULT;
2358
2359 len = min_t(unsigned int, len, sizeof(int));
2360
2361 if (len < 0)
2362 return -EINVAL;
2363
2364 switch (optname) {
2365 case TCP_MAXSEG:
2366 val = tp->mss_cache;
2367 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2368 val = tp->rx_opt.user_mss;
2369 break;
2370 case TCP_NODELAY:
2371 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2372 break;
2373 case TCP_CORK:
2374 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2375 break;
2376 case TCP_KEEPIDLE:
2377 val = keepalive_time_when(tp) / HZ;
2378 break;
2379 case TCP_KEEPINTVL:
2380 val = keepalive_intvl_when(tp) / HZ;
2381 break;
2382 case TCP_KEEPCNT:
2383 val = keepalive_probes(tp);
2384 break;
2385 case TCP_SYNCNT:
2386 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2387 break;
2388 case TCP_LINGER2:
2389 val = tp->linger2;
2390 if (val >= 0)
2391 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2392 break;
2393 case TCP_DEFER_ACCEPT:
2394 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2395 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2396 break;
2397 case TCP_WINDOW_CLAMP:
2398 val = tp->window_clamp;
2399 break;
2400 case TCP_INFO: {
2401 struct tcp_info info;
2402
2403 if (get_user(len, optlen))
2404 return -EFAULT;
2405
2406 tcp_get_info(sk, &info);
2407
2408 len = min_t(unsigned int, len, sizeof(info));
2409 if (put_user(len, optlen))
2410 return -EFAULT;
2411 if (copy_to_user(optval, &info, len))
2412 return -EFAULT;
2413 return 0;
2414 }
2415 case TCP_QUICKACK:
2416 val = !icsk->icsk_ack.pingpong;
2417 break;
2418
2419 case TCP_CONGESTION:
2420 if (get_user(len, optlen))
2421 return -EFAULT;
2422 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2423 if (put_user(len, optlen))
2424 return -EFAULT;
2425 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2426 return -EFAULT;
2427 return 0;
2428 default:
2429 return -ENOPROTOOPT;
2430 }
2431
2432 if (put_user(len, optlen))
2433 return -EFAULT;
2434 if (copy_to_user(optval, &val, len))
2435 return -EFAULT;
2436 return 0;
2437 }
2438
2439 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2440 int __user *optlen)
2441 {
2442 struct inet_connection_sock *icsk = inet_csk(sk);
2443
2444 if (level != SOL_TCP)
2445 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2446 optval, optlen);
2447 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2448 }
2449
2450 #ifdef CONFIG_COMPAT
2451 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2452 char __user *optval, int __user *optlen)
2453 {
2454 if (level != SOL_TCP)
2455 return inet_csk_compat_getsockopt(sk, level, optname,
2456 optval, optlen);
2457 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2458 }
2459
2460 EXPORT_SYMBOL(compat_tcp_getsockopt);
2461 #endif
2462
2463 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2464 {
2465 struct sk_buff *segs = ERR_PTR(-EINVAL);
2466 struct tcphdr *th;
2467 unsigned thlen;
2468 unsigned int seq;
2469 __be32 delta;
2470 unsigned int oldlen;
2471 unsigned int mss;
2472
2473 if (!pskb_may_pull(skb, sizeof(*th)))
2474 goto out;
2475
2476 th = tcp_hdr(skb);
2477 thlen = th->doff * 4;
2478 if (thlen < sizeof(*th))
2479 goto out;
2480
2481 if (!pskb_may_pull(skb, thlen))
2482 goto out;
2483
2484 oldlen = (u16)~skb->len;
2485 __skb_pull(skb, thlen);
2486
2487 mss = skb_shinfo(skb)->gso_size;
2488 if (unlikely(skb->len <= mss))
2489 goto out;
2490
2491 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2492 /* Packet is from an untrusted source, reset gso_segs. */
2493 int type = skb_shinfo(skb)->gso_type;
2494
2495 if (unlikely(type &
2496 ~(SKB_GSO_TCPV4 |
2497 SKB_GSO_DODGY |
2498 SKB_GSO_TCP_ECN |
2499 SKB_GSO_TCPV6 |
2500 0) ||
2501 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2502 goto out;
2503
2504 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2505
2506 segs = NULL;
2507 goto out;
2508 }
2509
2510 segs = skb_segment(skb, features);
2511 if (IS_ERR(segs))
2512 goto out;
2513
2514 delta = htonl(oldlen + (thlen + mss));
2515
2516 skb = segs;
2517 th = tcp_hdr(skb);
2518 seq = ntohl(th->seq);
2519
2520 do {
2521 th->fin = th->psh = 0;
2522
2523 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2524 (__force u32)delta));
2525 if (skb->ip_summed != CHECKSUM_PARTIAL)
2526 th->check =
2527 csum_fold(csum_partial(skb_transport_header(skb),
2528 thlen, skb->csum));
2529
2530 seq += mss;
2531 skb = skb->next;
2532 th = tcp_hdr(skb);
2533
2534 th->seq = htonl(seq);
2535 th->cwr = 0;
2536 } while (skb->next);
2537
2538 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2539 skb->data_len);
2540 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2541 (__force u32)delta));
2542 if (skb->ip_summed != CHECKSUM_PARTIAL)
2543 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2544 thlen, skb->csum));
2545
2546 out:
2547 return segs;
2548 }
2549 EXPORT_SYMBOL(tcp_tso_segment);
2550
2551 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2552 {
2553 struct sk_buff **pp = NULL;
2554 struct sk_buff *p;
2555 struct tcphdr *th;
2556 struct tcphdr *th2;
2557 unsigned int len;
2558 unsigned int thlen;
2559 unsigned int flags;
2560 unsigned int mss = 1;
2561 unsigned int hlen;
2562 unsigned int off;
2563 int flush = 1;
2564 int i;
2565
2566 off = skb_gro_offset(skb);
2567 hlen = off + sizeof(*th);
2568 th = skb_gro_header_fast(skb, off);
2569 if (skb_gro_header_hard(skb, hlen)) {
2570 th = skb_gro_header_slow(skb, hlen, off);
2571 if (unlikely(!th))
2572 goto out;
2573 }
2574
2575 thlen = th->doff * 4;
2576 if (thlen < sizeof(*th))
2577 goto out;
2578
2579 hlen = off + thlen;
2580 if (skb_gro_header_hard(skb, hlen)) {
2581 th = skb_gro_header_slow(skb, hlen, off);
2582 if (unlikely(!th))
2583 goto out;
2584 }
2585
2586 skb_gro_pull(skb, thlen);
2587
2588 len = skb_gro_len(skb);
2589 flags = tcp_flag_word(th);
2590
2591 for (; (p = *head); head = &p->next) {
2592 if (!NAPI_GRO_CB(p)->same_flow)
2593 continue;
2594
2595 th2 = tcp_hdr(p);
2596
2597 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2598 NAPI_GRO_CB(p)->same_flow = 0;
2599 continue;
2600 }
2601
2602 goto found;
2603 }
2604
2605 goto out_check_final;
2606
2607 found:
2608 flush = NAPI_GRO_CB(p)->flush;
2609 flush |= flags & TCP_FLAG_CWR;
2610 flush |= (flags ^ tcp_flag_word(th2)) &
2611 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH);
2612 flush |= th->ack_seq ^ th2->ack_seq;
2613 for (i = sizeof(*th); i < thlen; i += 4)
2614 flush |= *(u32 *)((u8 *)th + i) ^
2615 *(u32 *)((u8 *)th2 + i);
2616
2617 mss = skb_shinfo(p)->gso_size;
2618
2619 flush |= (len - 1) >= mss;
2620 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2621
2622 if (flush || skb_gro_receive(head, skb)) {
2623 mss = 1;
2624 goto out_check_final;
2625 }
2626
2627 p = *head;
2628 th2 = tcp_hdr(p);
2629 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2630
2631 out_check_final:
2632 flush = len < mss;
2633 flush |= flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST |
2634 TCP_FLAG_SYN | TCP_FLAG_FIN);
2635
2636 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2637 pp = head;
2638
2639 out:
2640 NAPI_GRO_CB(skb)->flush |= flush;
2641
2642 return pp;
2643 }
2644 EXPORT_SYMBOL(tcp_gro_receive);
2645
2646 int tcp_gro_complete(struct sk_buff *skb)
2647 {
2648 struct tcphdr *th = tcp_hdr(skb);
2649
2650 skb->csum_start = skb_transport_header(skb) - skb->head;
2651 skb->csum_offset = offsetof(struct tcphdr, check);
2652 skb->ip_summed = CHECKSUM_PARTIAL;
2653
2654 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2655
2656 if (th->cwr)
2657 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2658
2659 return 0;
2660 }
2661 EXPORT_SYMBOL(tcp_gro_complete);
2662
2663 #ifdef CONFIG_TCP_MD5SIG
2664 static unsigned long tcp_md5sig_users;
2665 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2666 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2667
2668 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2669 {
2670 int cpu;
2671 for_each_possible_cpu(cpu) {
2672 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2673 if (p) {
2674 if (p->md5_desc.tfm)
2675 crypto_free_hash(p->md5_desc.tfm);
2676 kfree(p);
2677 p = NULL;
2678 }
2679 }
2680 free_percpu(pool);
2681 }
2682
2683 void tcp_free_md5sig_pool(void)
2684 {
2685 struct tcp_md5sig_pool **pool = NULL;
2686
2687 spin_lock_bh(&tcp_md5sig_pool_lock);
2688 if (--tcp_md5sig_users == 0) {
2689 pool = tcp_md5sig_pool;
2690 tcp_md5sig_pool = NULL;
2691 }
2692 spin_unlock_bh(&tcp_md5sig_pool_lock);
2693 if (pool)
2694 __tcp_free_md5sig_pool(pool);
2695 }
2696
2697 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2698
2699 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(struct sock *sk)
2700 {
2701 int cpu;
2702 struct tcp_md5sig_pool **pool;
2703
2704 pool = alloc_percpu(struct tcp_md5sig_pool *);
2705 if (!pool)
2706 return NULL;
2707
2708 for_each_possible_cpu(cpu) {
2709 struct tcp_md5sig_pool *p;
2710 struct crypto_hash *hash;
2711
2712 p = kzalloc(sizeof(*p), sk->sk_allocation);
2713 if (!p)
2714 goto out_free;
2715 *per_cpu_ptr(pool, cpu) = p;
2716
2717 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2718 if (!hash || IS_ERR(hash))
2719 goto out_free;
2720
2721 p->md5_desc.tfm = hash;
2722 }
2723 return pool;
2724 out_free:
2725 __tcp_free_md5sig_pool(pool);
2726 return NULL;
2727 }
2728
2729 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(struct sock *sk)
2730 {
2731 struct tcp_md5sig_pool **pool;
2732 int alloc = 0;
2733
2734 retry:
2735 spin_lock_bh(&tcp_md5sig_pool_lock);
2736 pool = tcp_md5sig_pool;
2737 if (tcp_md5sig_users++ == 0) {
2738 alloc = 1;
2739 spin_unlock_bh(&tcp_md5sig_pool_lock);
2740 } else if (!pool) {
2741 tcp_md5sig_users--;
2742 spin_unlock_bh(&tcp_md5sig_pool_lock);
2743 cpu_relax();
2744 goto retry;
2745 } else
2746 spin_unlock_bh(&tcp_md5sig_pool_lock);
2747
2748 if (alloc) {
2749 /* we cannot hold spinlock here because this may sleep. */
2750 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool(sk);
2751 spin_lock_bh(&tcp_md5sig_pool_lock);
2752 if (!p) {
2753 tcp_md5sig_users--;
2754 spin_unlock_bh(&tcp_md5sig_pool_lock);
2755 return NULL;
2756 }
2757 pool = tcp_md5sig_pool;
2758 if (pool) {
2759 /* oops, it has already been assigned. */
2760 spin_unlock_bh(&tcp_md5sig_pool_lock);
2761 __tcp_free_md5sig_pool(p);
2762 } else {
2763 tcp_md5sig_pool = pool = p;
2764 spin_unlock_bh(&tcp_md5sig_pool_lock);
2765 }
2766 }
2767 return pool;
2768 }
2769
2770 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2771
2772 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2773 {
2774 struct tcp_md5sig_pool **p;
2775 spin_lock_bh(&tcp_md5sig_pool_lock);
2776 p = tcp_md5sig_pool;
2777 if (p)
2778 tcp_md5sig_users++;
2779 spin_unlock_bh(&tcp_md5sig_pool_lock);
2780 return (p ? *per_cpu_ptr(p, cpu) : NULL);
2781 }
2782
2783 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2784
2785 void __tcp_put_md5sig_pool(void)
2786 {
2787 tcp_free_md5sig_pool();
2788 }
2789
2790 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2791
2792 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2793 struct tcphdr *th)
2794 {
2795 struct scatterlist sg;
2796 int err;
2797
2798 __sum16 old_checksum = th->check;
2799 th->check = 0;
2800 /* options aren't included in the hash */
2801 sg_init_one(&sg, th, sizeof(struct tcphdr));
2802 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
2803 th->check = old_checksum;
2804 return err;
2805 }
2806
2807 EXPORT_SYMBOL(tcp_md5_hash_header);
2808
2809 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2810 struct sk_buff *skb, unsigned header_len)
2811 {
2812 struct scatterlist sg;
2813 const struct tcphdr *tp = tcp_hdr(skb);
2814 struct hash_desc *desc = &hp->md5_desc;
2815 unsigned i;
2816 const unsigned head_data_len = skb_headlen(skb) > header_len ?
2817 skb_headlen(skb) - header_len : 0;
2818 const struct skb_shared_info *shi = skb_shinfo(skb);
2819
2820 sg_init_table(&sg, 1);
2821
2822 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2823 if (crypto_hash_update(desc, &sg, head_data_len))
2824 return 1;
2825
2826 for (i = 0; i < shi->nr_frags; ++i) {
2827 const struct skb_frag_struct *f = &shi->frags[i];
2828 sg_set_page(&sg, f->page, f->size, f->page_offset);
2829 if (crypto_hash_update(desc, &sg, f->size))
2830 return 1;
2831 }
2832
2833 return 0;
2834 }
2835
2836 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
2837
2838 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
2839 {
2840 struct scatterlist sg;
2841
2842 sg_init_one(&sg, key->key, key->keylen);
2843 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
2844 }
2845
2846 EXPORT_SYMBOL(tcp_md5_hash_key);
2847
2848 #endif
2849
2850 void tcp_done(struct sock *sk)
2851 {
2852 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2853 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
2854
2855 tcp_set_state(sk, TCP_CLOSE);
2856 tcp_clear_xmit_timers(sk);
2857
2858 sk->sk_shutdown = SHUTDOWN_MASK;
2859
2860 if (!sock_flag(sk, SOCK_DEAD))
2861 sk->sk_state_change(sk);
2862 else
2863 inet_csk_destroy_sock(sk);
2864 }
2865 EXPORT_SYMBOL_GPL(tcp_done);
2866
2867 extern struct tcp_congestion_ops tcp_reno;
2868
2869 static __initdata unsigned long thash_entries;
2870 static int __init set_thash_entries(char *str)
2871 {
2872 if (!str)
2873 return 0;
2874 thash_entries = simple_strtoul(str, &str, 0);
2875 return 1;
2876 }
2877 __setup("thash_entries=", set_thash_entries);
2878
2879 void __init tcp_init(void)
2880 {
2881 struct sk_buff *skb = NULL;
2882 unsigned long nr_pages, limit;
2883 int order, i, max_share;
2884
2885 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
2886
2887 percpu_counter_init(&tcp_sockets_allocated, 0);
2888 percpu_counter_init(&tcp_orphan_count, 0);
2889 tcp_hashinfo.bind_bucket_cachep =
2890 kmem_cache_create("tcp_bind_bucket",
2891 sizeof(struct inet_bind_bucket), 0,
2892 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2893
2894 /* Size and allocate the main established and bind bucket
2895 * hash tables.
2896 *
2897 * The methodology is similar to that of the buffer cache.
2898 */
2899 tcp_hashinfo.ehash =
2900 alloc_large_system_hash("TCP established",
2901 sizeof(struct inet_ehash_bucket),
2902 thash_entries,
2903 (totalram_pages >= 128 * 1024) ?
2904 13 : 15,
2905 0,
2906 &tcp_hashinfo.ehash_size,
2907 NULL,
2908 thash_entries ? 0 : 512 * 1024);
2909 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2910 for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2911 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
2912 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
2913 }
2914 if (inet_ehash_locks_alloc(&tcp_hashinfo))
2915 panic("TCP: failed to alloc ehash_locks");
2916 tcp_hashinfo.bhash =
2917 alloc_large_system_hash("TCP bind",
2918 sizeof(struct inet_bind_hashbucket),
2919 tcp_hashinfo.ehash_size,
2920 (totalram_pages >= 128 * 1024) ?
2921 13 : 15,
2922 0,
2923 &tcp_hashinfo.bhash_size,
2924 NULL,
2925 64 * 1024);
2926 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2927 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2928 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2929 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2930 }
2931
2932 /* Try to be a bit smarter and adjust defaults depending
2933 * on available memory.
2934 */
2935 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2936 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2937 order++)
2938 ;
2939 if (order >= 4) {
2940 tcp_death_row.sysctl_max_tw_buckets = 180000;
2941 sysctl_tcp_max_orphans = 4096 << (order - 4);
2942 sysctl_max_syn_backlog = 1024;
2943 } else if (order < 3) {
2944 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2945 sysctl_tcp_max_orphans >>= (3 - order);
2946 sysctl_max_syn_backlog = 128;
2947 }
2948
2949 /* Set the pressure threshold to be a fraction of global memory that
2950 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2951 * memory, with a floor of 128 pages.
2952 */
2953 nr_pages = totalram_pages - totalhigh_pages;
2954 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
2955 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
2956 limit = max(limit, 128UL);
2957 sysctl_tcp_mem[0] = limit / 4 * 3;
2958 sysctl_tcp_mem[1] = limit;
2959 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
2960
2961 /* Set per-socket limits to no more than 1/128 the pressure threshold */
2962 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2963 max_share = min(4UL*1024*1024, limit);
2964
2965 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
2966 sysctl_tcp_wmem[1] = 16*1024;
2967 sysctl_tcp_wmem[2] = max(64*1024, max_share);
2968
2969 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
2970 sysctl_tcp_rmem[1] = 87380;
2971 sysctl_tcp_rmem[2] = max(87380, max_share);
2972
2973 printk(KERN_INFO "TCP: Hash tables configured "
2974 "(established %d bind %d)\n",
2975 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
2976
2977 tcp_register_congestion_control(&tcp_reno);
2978 }
2979
2980 EXPORT_SYMBOL(tcp_close);
2981 EXPORT_SYMBOL(tcp_disconnect);
2982 EXPORT_SYMBOL(tcp_getsockopt);
2983 EXPORT_SYMBOL(tcp_ioctl);
2984 EXPORT_SYMBOL(tcp_poll);
2985 EXPORT_SYMBOL(tcp_read_sock);
2986 EXPORT_SYMBOL(tcp_recvmsg);
2987 EXPORT_SYMBOL(tcp_sendmsg);
2988 EXPORT_SYMBOL(tcp_splice_read);
2989 EXPORT_SYMBOL(tcp_sendpage);
2990 EXPORT_SYMBOL(tcp_setsockopt);
2991 EXPORT_SYMBOL(tcp_shutdown);
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