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[NETFILTER]: don't use nested attributes for conntrack_expect
[linux-2.6/mini2440.git] / net / ipv4 / tcp.c
blobe54a410ca701b223aa1940881e786b96a74b17f9
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * Version: $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Mark Evans, <evansmp@uhura.aston.ac.uk>
13 * Corey Minyard <wf-rch!minyard@relay.EU.net>
14 * Florian La Roche, <flla@stud.uni-sb.de>
15 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
16 * Linus Torvalds, <torvalds@cs.helsinki.fi>
17 * Alan Cox, <gw4pts@gw4pts.ampr.org>
18 * Matthew Dillon, <dillon@apollo.west.oic.com>
19 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
20 * Jorge Cwik, <jorge@laser.satlink.net>
21 *
22 * Fixes:
23 * Alan Cox : Numerous verify_area() calls
24 * Alan Cox : Set the ACK bit on a reset
25 * Alan Cox : Stopped it crashing if it closed while
26 * sk->inuse=1 and was trying to connect
27 * (tcp_err()).
28 * Alan Cox : All icmp error handling was broken
29 * pointers passed where wrong and the
30 * socket was looked up backwards. Nobody
31 * tested any icmp error code obviously.
32 * Alan Cox : tcp_err() now handled properly. It
33 * wakes people on errors. poll
34 * behaves and the icmp error race
35 * has gone by moving it into sock.c
36 * Alan Cox : tcp_send_reset() fixed to work for
37 * everything not just packets for
38 * unknown sockets.
39 * Alan Cox : tcp option processing.
40 * Alan Cox : Reset tweaked (still not 100%) [Had
41 * syn rule wrong]
42 * Herp Rosmanith : More reset fixes
43 * Alan Cox : No longer acks invalid rst frames.
44 * Acking any kind of RST is right out.
45 * Alan Cox : Sets an ignore me flag on an rst
46 * receive otherwise odd bits of prattle
47 * escape still
48 * Alan Cox : Fixed another acking RST frame bug.
49 * Should stop LAN workplace lockups.
50 * Alan Cox : Some tidyups using the new skb list
51 * facilities
52 * Alan Cox : sk->keepopen now seems to work
53 * Alan Cox : Pulls options out correctly on accepts
54 * Alan Cox : Fixed assorted sk->rqueue->next errors
55 * Alan Cox : PSH doesn't end a TCP read. Switched a
56 * bit to skb ops.
57 * Alan Cox : Tidied tcp_data to avoid a potential
58 * nasty.
59 * Alan Cox : Added some better commenting, as the
60 * tcp is hard to follow
61 * Alan Cox : Removed incorrect check for 20 * psh
62 * Michael O'Reilly : ack < copied bug fix.
63 * Johannes Stille : Misc tcp fixes (not all in yet).
64 * Alan Cox : FIN with no memory -> CRASH
65 * Alan Cox : Added socket option proto entries.
66 * Also added awareness of them to accept.
67 * Alan Cox : Added TCP options (SOL_TCP)
68 * Alan Cox : Switched wakeup calls to callbacks,
69 * so the kernel can layer network
70 * sockets.
71 * Alan Cox : Use ip_tos/ip_ttl settings.
72 * Alan Cox : Handle FIN (more) properly (we hope).
73 * Alan Cox : RST frames sent on unsynchronised
74 * state ack error.
75 * Alan Cox : Put in missing check for SYN bit.
76 * Alan Cox : Added tcp_select_window() aka NET2E
77 * window non shrink trick.
78 * Alan Cox : Added a couple of small NET2E timer
79 * fixes
80 * Charles Hedrick : TCP fixes
81 * Toomas Tamm : TCP window fixes
82 * Alan Cox : Small URG fix to rlogin ^C ack fight
83 * Charles Hedrick : Rewrote most of it to actually work
84 * Linus : Rewrote tcp_read() and URG handling
85 * completely
86 * Gerhard Koerting: Fixed some missing timer handling
87 * Matthew Dillon : Reworked TCP machine states as per RFC
88 * Gerhard Koerting: PC/TCP workarounds
89 * Adam Caldwell : Assorted timer/timing errors
90 * Matthew Dillon : Fixed another RST bug
91 * Alan Cox : Move to kernel side addressing changes.
92 * Alan Cox : Beginning work on TCP fastpathing
93 * (not yet usable)
94 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
95 * Alan Cox : TCP fast path debugging
96 * Alan Cox : Window clamping
97 * Michael Riepe : Bug in tcp_check()
98 * Matt Dillon : More TCP improvements and RST bug fixes
99 * Matt Dillon : Yet more small nasties remove from the
100 * TCP code (Be very nice to this man if
101 * tcp finally works 100%) 8)
102 * Alan Cox : BSD accept semantics.
103 * Alan Cox : Reset on closedown bug.
104 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
105 * Michael Pall : Handle poll() after URG properly in
106 * all cases.
107 * Michael Pall : Undo the last fix in tcp_read_urg()
108 * (multi URG PUSH broke rlogin).
109 * Michael Pall : Fix the multi URG PUSH problem in
110 * tcp_readable(), poll() after URG
111 * works now.
112 * Michael Pall : recv(...,MSG_OOB) never blocks in the
113 * BSD api.
114 * Alan Cox : Changed the semantics of sk->socket to
115 * fix a race and a signal problem with
116 * accept() and async I/O.
117 * Alan Cox : Relaxed the rules on tcp_sendto().
118 * Yury Shevchuk : Really fixed accept() blocking problem.
119 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
120 * clients/servers which listen in on
121 * fixed ports.
122 * Alan Cox : Cleaned the above up and shrank it to
123 * a sensible code size.
124 * Alan Cox : Self connect lockup fix.
125 * Alan Cox : No connect to multicast.
126 * Ross Biro : Close unaccepted children on master
127 * socket close.
128 * Alan Cox : Reset tracing code.
129 * Alan Cox : Spurious resets on shutdown.
130 * Alan Cox : Giant 15 minute/60 second timer error
131 * Alan Cox : Small whoops in polling before an
132 * accept.
133 * Alan Cox : Kept the state trace facility since
134 * it's handy for debugging.
135 * Alan Cox : More reset handler fixes.
136 * Alan Cox : Started rewriting the code based on
137 * the RFC's for other useful protocol
138 * references see: Comer, KA9Q NOS, and
139 * for a reference on the difference
140 * between specifications and how BSD
141 * works see the 4.4lite source.
142 * A.N.Kuznetsov : Don't time wait on completion of tidy
143 * close.
144 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
145 * Linus Torvalds : Fixed BSD port reuse to work first syn
146 * Alan Cox : Reimplemented timers as per the RFC
147 * and using multiple timers for sanity.
148 * Alan Cox : Small bug fixes, and a lot of new
149 * comments.
150 * Alan Cox : Fixed dual reader crash by locking
151 * the buffers (much like datagram.c)
152 * Alan Cox : Fixed stuck sockets in probe. A probe
153 * now gets fed up of retrying without
154 * (even a no space) answer.
155 * Alan Cox : Extracted closing code better
156 * Alan Cox : Fixed the closing state machine to
157 * resemble the RFC.
158 * Alan Cox : More 'per spec' fixes.
159 * Jorge Cwik : Even faster checksumming.
160 * Alan Cox : tcp_data() doesn't ack illegal PSH
161 * only frames. At least one pc tcp stack
162 * generates them.
163 * Alan Cox : Cache last socket.
164 * Alan Cox : Per route irtt.
165 * Matt Day : poll()->select() match BSD precisely on error
166 * Alan Cox : New buffers
167 * Marc Tamsky : Various sk->prot->retransmits and
168 * sk->retransmits misupdating fixed.
169 * Fixed tcp_write_timeout: stuck close,
170 * and TCP syn retries gets used now.
171 * Mark Yarvis : In tcp_read_wakeup(), don't send an
172 * ack if state is TCP_CLOSED.
173 * Alan Cox : Look up device on a retransmit - routes may
174 * change. Doesn't yet cope with MSS shrink right
175 * but it's a start!
176 * Marc Tamsky : Closing in closing fixes.
177 * Mike Shaver : RFC1122 verifications.
178 * Alan Cox : rcv_saddr errors.
179 * Alan Cox : Block double connect().
180 * Alan Cox : Small hooks for enSKIP.
181 * Alexey Kuznetsov: Path MTU discovery.
182 * Alan Cox : Support soft errors.
183 * Alan Cox : Fix MTU discovery pathological case
184 * when the remote claims no mtu!
185 * Marc Tamsky : TCP_CLOSE fix.
186 * Colin (G3TNE) : Send a reset on syn ack replies in
187 * window but wrong (fixes NT lpd problems)
188 * Pedro Roque : Better TCP window handling, delayed ack.
189 * Joerg Reuter : No modification of locked buffers in
190 * tcp_do_retransmit()
191 * Eric Schenk : Changed receiver side silly window
192 * avoidance algorithm to BSD style
193 * algorithm. This doubles throughput
194 * against machines running Solaris,
195 * and seems to result in general
196 * improvement.
197 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
198 * Willy Konynenberg : Transparent proxying support.
199 * Mike McLagan : Routing by source
200 * Keith Owens : Do proper merging with partial SKB's in
201 * tcp_do_sendmsg to avoid burstiness.
202 * Eric Schenk : Fix fast close down bug with
203 * shutdown() followed by close().
204 * Andi Kleen : Make poll agree with SIGIO
205 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
206 * lingertime == 0 (RFC 793 ABORT Call)
207 * Hirokazu Takahashi : Use copy_from_user() instead of
208 * csum_and_copy_from_user() if possible.
209 *
210 * This program is free software; you can redistribute it and/or
211 * modify it under the terms of the GNU General Public License
212 * as published by the Free Software Foundation; either version
213 * 2 of the License, or(at your option) any later version.
214 *
215 * Description of States:
216 *
217 * TCP_SYN_SENT sent a connection request, waiting for ack
218 *
219 * TCP_SYN_RECV received a connection request, sent ack,
220 * waiting for final ack in three-way handshake.
221 *
222 * TCP_ESTABLISHED connection established
223 *
224 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
225 * transmission of remaining buffered data
226 *
227 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
228 * to shutdown
229 *
230 * TCP_CLOSING both sides have shutdown but we still have
231 * data we have to finish sending
232 *
233 * TCP_TIME_WAIT timeout to catch resent junk before entering
234 * closed, can only be entered from FIN_WAIT2
235 * or CLOSING. Required because the other end
236 * may not have gotten our last ACK causing it
237 * to retransmit the data packet (which we ignore)
238 *
239 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
240 * us to finish writing our data and to shutdown
241 * (we have to close() to move on to LAST_ACK)
242 *
243 * TCP_LAST_ACK out side has shutdown after remote has
244 * shutdown. There may still be data in our
245 * buffer that we have to finish sending
246 *
247 * TCP_CLOSE socket is finished
248 */
249
250 #include <linux/config.h>
251 #include <linux/module.h>
252 #include <linux/types.h>
253 #include <linux/fcntl.h>
254 #include <linux/poll.h>
255 #include <linux/init.h>
256 #include <linux/smp_lock.h>
257 #include <linux/fs.h>
258 #include <linux/random.h>
259 #include <linux/bootmem.h>
260
261 #include <net/icmp.h>
262 #include <net/tcp.h>
263 #include <net/xfrm.h>
264 #include <net/ip.h>
265
266
267 #include <asm/uaccess.h>
268 #include <asm/ioctls.h>
269
270 int sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
271
272 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics);
273
274 kmem_cache_t *tcp_bucket_cachep;
275
276 EXPORT_SYMBOL_GPL(tcp_bucket_cachep);
277
278 kmem_cache_t *tcp_timewait_cachep;
279
280 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
281
282 int sysctl_tcp_mem[3];
283 int sysctl_tcp_wmem[3] = { 4 * 1024, 16 * 1024, 128 * 1024 };
284 int sysctl_tcp_rmem[3] = { 4 * 1024, 87380, 87380 * 2 };
285
286 EXPORT_SYMBOL(sysctl_tcp_mem);
287 EXPORT_SYMBOL(sysctl_tcp_rmem);
288 EXPORT_SYMBOL(sysctl_tcp_wmem);
289
290 atomic_t tcp_memory_allocated; /* Current allocated memory. */
291 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
292
293 EXPORT_SYMBOL(tcp_memory_allocated);
294 EXPORT_SYMBOL(tcp_sockets_allocated);
295
296 /*
297 * Pressure flag: try to collapse.
298 * Technical note: it is used by multiple contexts non atomically.
299 * All the sk_stream_mem_schedule() is of this nature: accounting
300 * is strict, actions are advisory and have some latency.
301 */
302 int tcp_memory_pressure;
303
304 EXPORT_SYMBOL(tcp_memory_pressure);
305
306 void tcp_enter_memory_pressure(void)
307 {
308 if (!tcp_memory_pressure) {
309 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
310 tcp_memory_pressure = 1;
311 }
312 }
313
314 EXPORT_SYMBOL(tcp_enter_memory_pressure);
315
316 /*
317 * LISTEN is a special case for poll..
318 */
319 static __inline__ unsigned int tcp_listen_poll(struct sock *sk,
320 poll_table *wait)
321 {
322 return !reqsk_queue_empty(&tcp_sk(sk)->accept_queue) ? (POLLIN | POLLRDNORM) : 0;
323 }
324
325 /*
326 * Wait for a TCP event.
327 *
328 * Note that we don't need to lock the socket, as the upper poll layers
329 * take care of normal races (between the test and the event) and we don't
330 * go look at any of the socket buffers directly.
331 */
332 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
333 {
334 unsigned int mask;
335 struct sock *sk = sock->sk;
336 struct tcp_sock *tp = tcp_sk(sk);
337
338 poll_wait(file, sk->sk_sleep, wait);
339 if (sk->sk_state == TCP_LISTEN)
340 return tcp_listen_poll(sk, wait);
341
342 /* Socket is not locked. We are protected from async events
343 by poll logic and correct handling of state changes
344 made by another threads is impossible in any case.
345 */
346
347 mask = 0;
348 if (sk->sk_err)
349 mask = POLLERR;
350
351 /*
352 * POLLHUP is certainly not done right. But poll() doesn't
353 * have a notion of HUP in just one direction, and for a
354 * socket the read side is more interesting.
355 *
356 * Some poll() documentation says that POLLHUP is incompatible
357 * with the POLLOUT/POLLWR flags, so somebody should check this
358 * all. But careful, it tends to be safer to return too many
359 * bits than too few, and you can easily break real applications
360 * if you don't tell them that something has hung up!
361 *
362 * Check-me.
363 *
364 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
365 * our fs/select.c). It means that after we received EOF,
366 * poll always returns immediately, making impossible poll() on write()
367 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
368 * if and only if shutdown has been made in both directions.
369 * Actually, it is interesting to look how Solaris and DUX
370 * solve this dilemma. I would prefer, if PULLHUP were maskable,
371 * then we could set it on SND_SHUTDOWN. BTW examples given
372 * in Stevens' books assume exactly this behaviour, it explains
373 * why PULLHUP is incompatible with POLLOUT. --ANK
374 *
375 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
376 * blocking on fresh not-connected or disconnected socket. --ANK
377 */
378 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
379 mask |= POLLHUP;
380 if (sk->sk_shutdown & RCV_SHUTDOWN)
381 mask |= POLLIN | POLLRDNORM;
382
383 /* Connected? */
384 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
385 /* Potential race condition. If read of tp below will
386 * escape above sk->sk_state, we can be illegally awaken
387 * in SYN_* states. */
388 if ((tp->rcv_nxt != tp->copied_seq) &&
389 (tp->urg_seq != tp->copied_seq ||
390 tp->rcv_nxt != tp->copied_seq + 1 ||
391 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
392 mask |= POLLIN | POLLRDNORM;
393
394 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
395 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
396 mask |= POLLOUT | POLLWRNORM;
397 } else { /* send SIGIO later */
398 set_bit(SOCK_ASYNC_NOSPACE,
399 &sk->sk_socket->flags);
400 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
401
402 /* Race breaker. If space is freed after
403 * wspace test but before the flags are set,
404 * IO signal will be lost.
405 */
406 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
407 mask |= POLLOUT | POLLWRNORM;
408 }
409 }
410
411 if (tp->urg_data & TCP_URG_VALID)
412 mask |= POLLPRI;
413 }
414 return mask;
415 }
416
417 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
418 {
419 struct tcp_sock *tp = tcp_sk(sk);
420 int answ;
421
422 switch (cmd) {
423 case SIOCINQ:
424 if (sk->sk_state == TCP_LISTEN)
425 return -EINVAL;
426
427 lock_sock(sk);
428 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
429 answ = 0;
430 else if (sock_flag(sk, SOCK_URGINLINE) ||
431 !tp->urg_data ||
432 before(tp->urg_seq, tp->copied_seq) ||
433 !before(tp->urg_seq, tp->rcv_nxt)) {
434 answ = tp->rcv_nxt - tp->copied_seq;
435
436 /* Subtract 1, if FIN is in queue. */
437 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
438 answ -=
439 ((struct sk_buff *)sk->sk_receive_queue.prev)->h.th->fin;
440 } else
441 answ = tp->urg_seq - tp->copied_seq;
442 release_sock(sk);
443 break;
444 case SIOCATMARK:
445 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
446 break;
447 case SIOCOUTQ:
448 if (sk->sk_state == TCP_LISTEN)
449 return -EINVAL;
450
451 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
452 answ = 0;
453 else
454 answ = tp->write_seq - tp->snd_una;
455 break;
456 default:
457 return -ENOIOCTLCMD;
458 };
459
460 return put_user(answ, (int __user *)arg);
461 }
462
463
464 int tcp_listen_start(struct sock *sk)
465 {
466 struct inet_sock *inet = inet_sk(sk);
467 struct tcp_sock *tp = tcp_sk(sk);
468 int rc = reqsk_queue_alloc(&tp->accept_queue, TCP_SYNQ_HSIZE);
469
470 if (rc != 0)
471 return rc;
472
473 sk->sk_max_ack_backlog = 0;
474 sk->sk_ack_backlog = 0;
475 tcp_delack_init(tp);
476
477 /* There is race window here: we announce ourselves listening,
478 * but this transition is still not validated by get_port().
479 * It is OK, because this socket enters to hash table only
480 * after validation is complete.
481 */
482 sk->sk_state = TCP_LISTEN;
483 if (!sk->sk_prot->get_port(sk, inet->num)) {
484 inet->sport = htons(inet->num);
485
486 sk_dst_reset(sk);
487 sk->sk_prot->hash(sk);
488
489 return 0;
490 }
491
492 sk->sk_state = TCP_CLOSE;
493 __reqsk_queue_destroy(&tp->accept_queue);
494 return -EADDRINUSE;
495 }
496
497 /*
498 * This routine closes sockets which have been at least partially
499 * opened, but not yet accepted.
500 */
501
502 static void tcp_listen_stop (struct sock *sk)
503 {
504 struct tcp_sock *tp = tcp_sk(sk);
505 struct request_sock *acc_req;
506 struct request_sock *req;
507
508 tcp_delete_keepalive_timer(sk);
509
510 /* make all the listen_opt local to us */
511 acc_req = reqsk_queue_yank_acceptq(&tp->accept_queue);
512
513 /* Following specs, it would be better either to send FIN
514 * (and enter FIN-WAIT-1, it is normal close)
515 * or to send active reset (abort).
516 * Certainly, it is pretty dangerous while synflood, but it is
517 * bad justification for our negligence 8)
518 * To be honest, we are not able to make either
519 * of the variants now. --ANK
520 */
521 reqsk_queue_destroy(&tp->accept_queue);
522
523 while ((req = acc_req) != NULL) {
524 struct sock *child = req->sk;
525
526 acc_req = req->dl_next;
527
528 local_bh_disable();
529 bh_lock_sock(child);
530 BUG_TRAP(!sock_owned_by_user(child));
531 sock_hold(child);
532
533 tcp_disconnect(child, O_NONBLOCK);
534
535 sock_orphan(child);
536
537 atomic_inc(&tcp_orphan_count);
538
539 tcp_destroy_sock(child);
540
541 bh_unlock_sock(child);
542 local_bh_enable();
543 sock_put(child);
544
545 sk_acceptq_removed(sk);
546 __reqsk_free(req);
547 }
548 BUG_TRAP(!sk->sk_ack_backlog);
549 }
550
551 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
552 {
553 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
554 tp->pushed_seq = tp->write_seq;
555 }
556
557 static inline int forced_push(struct tcp_sock *tp)
558 {
559 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
560 }
561
562 static inline void skb_entail(struct sock *sk, struct tcp_sock *tp,
563 struct sk_buff *skb)
564 {
565 skb->csum = 0;
566 TCP_SKB_CB(skb)->seq = tp->write_seq;
567 TCP_SKB_CB(skb)->end_seq = tp->write_seq;
568 TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
569 TCP_SKB_CB(skb)->sacked = 0;
570 skb_header_release(skb);
571 __skb_queue_tail(&sk->sk_write_queue, skb);
572 sk_charge_skb(sk, skb);
573 if (!sk->sk_send_head)
574 sk->sk_send_head = skb;
575 if (tp->nonagle & TCP_NAGLE_PUSH)
576 tp->nonagle &= ~TCP_NAGLE_PUSH;
577 }
578
579 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
580 struct sk_buff *skb)
581 {
582 if (flags & MSG_OOB) {
583 tp->urg_mode = 1;
584 tp->snd_up = tp->write_seq;
585 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
586 }
587 }
588
589 static inline void tcp_push(struct sock *sk, struct tcp_sock *tp, int flags,
590 int mss_now, int nonagle)
591 {
592 if (sk->sk_send_head) {
593 struct sk_buff *skb = sk->sk_write_queue.prev;
594 if (!(flags & MSG_MORE) || forced_push(tp))
595 tcp_mark_push(tp, skb);
596 tcp_mark_urg(tp, flags, skb);
597 __tcp_push_pending_frames(sk, tp, mss_now,
598 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
599 }
600 }
601
602 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
603 size_t psize, int flags)
604 {
605 struct tcp_sock *tp = tcp_sk(sk);
606 int mss_now, size_goal;
607 int err;
608 ssize_t copied;
609 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
610
611 /* Wait for a connection to finish. */
612 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
613 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
614 goto out_err;
615
616 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
617
618 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
619 size_goal = tp->xmit_size_goal;
620 copied = 0;
621
622 err = -EPIPE;
623 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
624 goto do_error;
625
626 while (psize > 0) {
627 struct sk_buff *skb = sk->sk_write_queue.prev;
628 struct page *page = pages[poffset / PAGE_SIZE];
629 int copy, i, can_coalesce;
630 int offset = poffset % PAGE_SIZE;
631 int size = min_t(size_t, psize, PAGE_SIZE - offset);
632
633 if (!sk->sk_send_head || (copy = size_goal - skb->len) <= 0) {
634 new_segment:
635 if (!sk_stream_memory_free(sk))
636 goto wait_for_sndbuf;
637
638 skb = sk_stream_alloc_pskb(sk, 0, 0,
639 sk->sk_allocation);
640 if (!skb)
641 goto wait_for_memory;
642
643 skb_entail(sk, tp, skb);
644 copy = size_goal;
645 }
646
647 if (copy > size)
648 copy = size;
649
650 i = skb_shinfo(skb)->nr_frags;
651 can_coalesce = skb_can_coalesce(skb, i, page, offset);
652 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
653 tcp_mark_push(tp, skb);
654 goto new_segment;
655 }
656 if (sk->sk_forward_alloc < copy &&
657 !sk_stream_mem_schedule(sk, copy, 0))
658 goto wait_for_memory;
659
660 if (can_coalesce) {
661 skb_shinfo(skb)->frags[i - 1].size += copy;
662 } else {
663 get_page(page);
664 skb_fill_page_desc(skb, i, page, offset, copy);
665 }
666
667 skb->len += copy;
668 skb->data_len += copy;
669 skb->truesize += copy;
670 sk->sk_wmem_queued += copy;
671 sk->sk_forward_alloc -= copy;
672 skb->ip_summed = CHECKSUM_HW;
673 tp->write_seq += copy;
674 TCP_SKB_CB(skb)->end_seq += copy;
675 skb_shinfo(skb)->tso_segs = 0;
676
677 if (!copied)
678 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
679
680 copied += copy;
681 poffset += copy;
682 if (!(psize -= copy))
683 goto out;
684
685 if (skb->len < mss_now || (flags & MSG_OOB))
686 continue;
687
688 if (forced_push(tp)) {
689 tcp_mark_push(tp, skb);
690 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
691 } else if (skb == sk->sk_send_head)
692 tcp_push_one(sk, mss_now);
693 continue;
694
695 wait_for_sndbuf:
696 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
697 wait_for_memory:
698 if (copied)
699 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
700
701 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
702 goto do_error;
703
704 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
705 size_goal = tp->xmit_size_goal;
706 }
707
708 out:
709 if (copied)
710 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
711 return copied;
712
713 do_error:
714 if (copied)
715 goto out;
716 out_err:
717 return sk_stream_error(sk, flags, err);
718 }
719
720 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
721 size_t size, int flags)
722 {
723 ssize_t res;
724 struct sock *sk = sock->sk;
725
726 #define TCP_ZC_CSUM_FLAGS (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)
727
728 if (!(sk->sk_route_caps & NETIF_F_SG) ||
729 !(sk->sk_route_caps & TCP_ZC_CSUM_FLAGS))
730 return sock_no_sendpage(sock, page, offset, size, flags);
731
732 #undef TCP_ZC_CSUM_FLAGS
733
734 lock_sock(sk);
735 TCP_CHECK_TIMER(sk);
736 res = do_tcp_sendpages(sk, &page, offset, size, flags);
737 TCP_CHECK_TIMER(sk);
738 release_sock(sk);
739 return res;
740 }
741
742 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
743 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
744
745 static inline int select_size(struct sock *sk, struct tcp_sock *tp)
746 {
747 int tmp = tp->mss_cache;
748
749 if (sk->sk_route_caps & NETIF_F_SG) {
750 if (sk->sk_route_caps & NETIF_F_TSO)
751 tmp = 0;
752 else {
753 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
754
755 if (tmp >= pgbreak &&
756 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
757 tmp = pgbreak;
758 }
759 }
760
761 return tmp;
762 }
763
764 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
765 size_t size)
766 {
767 struct iovec *iov;
768 struct tcp_sock *tp = tcp_sk(sk);
769 struct sk_buff *skb;
770 int iovlen, flags;
771 int mss_now, size_goal;
772 int err, copied;
773 long timeo;
774
775 lock_sock(sk);
776 TCP_CHECK_TIMER(sk);
777
778 flags = msg->msg_flags;
779 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
780
781 /* Wait for a connection to finish. */
782 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
783 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
784 goto out_err;
785
786 /* This should be in poll */
787 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
788
789 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
790 size_goal = tp->xmit_size_goal;
791
792 /* Ok commence sending. */
793 iovlen = msg->msg_iovlen;
794 iov = msg->msg_iov;
795 copied = 0;
796
797 err = -EPIPE;
798 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
799 goto do_error;
800
801 while (--iovlen >= 0) {
802 int seglen = iov->iov_len;
803 unsigned char __user *from = iov->iov_base;
804
805 iov++;
806
807 while (seglen > 0) {
808 int copy;
809
810 skb = sk->sk_write_queue.prev;
811
812 if (!sk->sk_send_head ||
813 (copy = size_goal - skb->len) <= 0) {
814
815 new_segment:
816 /* Allocate new segment. If the interface is SG,
817 * allocate skb fitting to single page.
818 */
819 if (!sk_stream_memory_free(sk))
820 goto wait_for_sndbuf;
821
822 skb = sk_stream_alloc_pskb(sk, select_size(sk, tp),
823 0, sk->sk_allocation);
824 if (!skb)
825 goto wait_for_memory;
826
827 /*
828 * Check whether we can use HW checksum.
829 */
830 if (sk->sk_route_caps &
831 (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM |
832 NETIF_F_HW_CSUM))
833 skb->ip_summed = CHECKSUM_HW;
834
835 skb_entail(sk, tp, skb);
836 copy = size_goal;
837 }
838
839 /* Try to append data to the end of skb. */
840 if (copy > seglen)
841 copy = seglen;
842
843 /* Where to copy to? */
844 if (skb_tailroom(skb) > 0) {
845 /* We have some space in skb head. Superb! */
846 if (copy > skb_tailroom(skb))
847 copy = skb_tailroom(skb);
848 if ((err = skb_add_data(skb, from, copy)) != 0)
849 goto do_fault;
850 } else {
851 int merge = 0;
852 int i = skb_shinfo(skb)->nr_frags;
853 struct page *page = TCP_PAGE(sk);
854 int off = TCP_OFF(sk);
855
856 if (skb_can_coalesce(skb, i, page, off) &&
857 off != PAGE_SIZE) {
858 /* We can extend the last page
859 * fragment. */
860 merge = 1;
861 } else if (i == MAX_SKB_FRAGS ||
862 (!i &&
863 !(sk->sk_route_caps & NETIF_F_SG))) {
864 /* Need to add new fragment and cannot
865 * do this because interface is non-SG,
866 * or because all the page slots are
867 * busy. */
868 tcp_mark_push(tp, skb);
869 goto new_segment;
870 } else if (page) {
871 if (off == PAGE_SIZE) {
872 put_page(page);
873 TCP_PAGE(sk) = page = NULL;
874 }
875 }
876
877 if (!page) {
878 /* Allocate new cache page. */
879 if (!(page = sk_stream_alloc_page(sk)))
880 goto wait_for_memory;
881 off = 0;
882 }
883
884 if (copy > PAGE_SIZE - off)
885 copy = PAGE_SIZE - off;
886
887 /* Time to copy data. We are close to
888 * the end! */
889 err = skb_copy_to_page(sk, from, skb, page,
890 off, copy);
891 if (err) {
892 /* If this page was new, give it to the
893 * socket so it does not get leaked.
894 */
895 if (!TCP_PAGE(sk)) {
896 TCP_PAGE(sk) = page;
897 TCP_OFF(sk) = 0;
898 }
899 goto do_error;
900 }
901
902 /* Update the skb. */
903 if (merge) {
904 skb_shinfo(skb)->frags[i - 1].size +=
905 copy;
906 } else {
907 skb_fill_page_desc(skb, i, page, off, copy);
908 if (TCP_PAGE(sk)) {
909 get_page(page);
910 } else if (off + copy < PAGE_SIZE) {
911 get_page(page);
912 TCP_PAGE(sk) = page;
913 }
914 }
915
916 TCP_OFF(sk) = off + copy;
917 }
918
919 if (!copied)
920 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
921
922 tp->write_seq += copy;
923 TCP_SKB_CB(skb)->end_seq += copy;
924 skb_shinfo(skb)->tso_segs = 0;
925
926 from += copy;
927 copied += copy;
928 if ((seglen -= copy) == 0 && iovlen == 0)
929 goto out;
930
931 if (skb->len < mss_now || (flags & MSG_OOB))
932 continue;
933
934 if (forced_push(tp)) {
935 tcp_mark_push(tp, skb);
936 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
937 } else if (skb == sk->sk_send_head)
938 tcp_push_one(sk, mss_now);
939 continue;
940
941 wait_for_sndbuf:
942 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
943 wait_for_memory:
944 if (copied)
945 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
946
947 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
948 goto do_error;
949
950 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
951 size_goal = tp->xmit_size_goal;
952 }
953 }
954
955 out:
956 if (copied)
957 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
958 TCP_CHECK_TIMER(sk);
959 release_sock(sk);
960 return copied;
961
962 do_fault:
963 if (!skb->len) {
964 if (sk->sk_send_head == skb)
965 sk->sk_send_head = NULL;
966 __skb_unlink(skb, &sk->sk_write_queue);
967 sk_stream_free_skb(sk, skb);
968 }
969
970 do_error:
971 if (copied)
972 goto out;
973 out_err:
974 err = sk_stream_error(sk, flags, err);
975 TCP_CHECK_TIMER(sk);
976 release_sock(sk);
977 return err;
978 }
979
980 /*
981 * Handle reading urgent data. BSD has very simple semantics for
982 * this, no blocking and very strange errors 8)
983 */
984
985 static int tcp_recv_urg(struct sock *sk, long timeo,
986 struct msghdr *msg, int len, int flags,
987 int *addr_len)
988 {
989 struct tcp_sock *tp = tcp_sk(sk);
990
991 /* No URG data to read. */
992 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
993 tp->urg_data == TCP_URG_READ)
994 return -EINVAL; /* Yes this is right ! */
995
996 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
997 return -ENOTCONN;
998
999 if (tp->urg_data & TCP_URG_VALID) {
1000 int err = 0;
1001 char c = tp->urg_data;
1002
1003 if (!(flags & MSG_PEEK))
1004 tp->urg_data = TCP_URG_READ;
1005
1006 /* Read urgent data. */
1007 msg->msg_flags |= MSG_OOB;
1008
1009 if (len > 0) {
1010 if (!(flags & MSG_TRUNC))
1011 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1012 len = 1;
1013 } else
1014 msg->msg_flags |= MSG_TRUNC;
1015
1016 return err ? -EFAULT : len;
1017 }
1018
1019 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1020 return 0;
1021
1022 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1023 * the available implementations agree in this case:
1024 * this call should never block, independent of the
1025 * blocking state of the socket.
1026 * Mike <pall@rz.uni-karlsruhe.de>
1027 */
1028 return -EAGAIN;
1029 }
1030
1031 /* Clean up the receive buffer for full frames taken by the user,
1032 * then send an ACK if necessary. COPIED is the number of bytes
1033 * tcp_recvmsg has given to the user so far, it speeds up the
1034 * calculation of whether or not we must ACK for the sake of
1035 * a window update.
1036 */
1037 static void cleanup_rbuf(struct sock *sk, int copied)
1038 {
1039 struct tcp_sock *tp = tcp_sk(sk);
1040 int time_to_ack = 0;
1041
1042 #if TCP_DEBUG
1043 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1044
1045 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
1046 #endif
1047
1048 if (tcp_ack_scheduled(tp)) {
1049 /* Delayed ACKs frequently hit locked sockets during bulk
1050 * receive. */
1051 if (tp->ack.blocked ||
1052 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1053 tp->rcv_nxt - tp->rcv_wup > tp->ack.rcv_mss ||
1054 /*
1055 * If this read emptied read buffer, we send ACK, if
1056 * connection is not bidirectional, user drained
1057 * receive buffer and there was a small segment
1058 * in queue.
1059 */
1060 (copied > 0 && (tp->ack.pending & TCP_ACK_PUSHED) &&
1061 !tp->ack.pingpong && !atomic_read(&sk->sk_rmem_alloc)))
1062 time_to_ack = 1;
1063 }
1064
1065 /* We send an ACK if we can now advertise a non-zero window
1066 * which has been raised "significantly".
1067 *
1068 * Even if window raised up to infinity, do not send window open ACK
1069 * in states, where we will not receive more. It is useless.
1070 */
1071 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1072 __u32 rcv_window_now = tcp_receive_window(tp);
1073
1074 /* Optimize, __tcp_select_window() is not cheap. */
1075 if (2*rcv_window_now <= tp->window_clamp) {
1076 __u32 new_window = __tcp_select_window(sk);
1077
1078 /* Send ACK now, if this read freed lots of space
1079 * in our buffer. Certainly, new_window is new window.
1080 * We can advertise it now, if it is not less than current one.
1081 * "Lots" means "at least twice" here.
1082 */
1083 if (new_window && new_window >= 2 * rcv_window_now)
1084 time_to_ack = 1;
1085 }
1086 }
1087 if (time_to_ack)
1088 tcp_send_ack(sk);
1089 }
1090
1091 static void tcp_prequeue_process(struct sock *sk)
1092 {
1093 struct sk_buff *skb;
1094 struct tcp_sock *tp = tcp_sk(sk);
1095
1096 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
1097
1098 /* RX process wants to run with disabled BHs, though it is not
1099 * necessary */
1100 local_bh_disable();
1101 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1102 sk->sk_backlog_rcv(sk, skb);
1103 local_bh_enable();
1104
1105 /* Clear memory counter. */
1106 tp->ucopy.memory = 0;
1107 }
1108
1109 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1110 {
1111 struct sk_buff *skb;
1112 u32 offset;
1113
1114 skb_queue_walk(&sk->sk_receive_queue, skb) {
1115 offset = seq - TCP_SKB_CB(skb)->seq;
1116 if (skb->h.th->syn)
1117 offset--;
1118 if (offset < skb->len || skb->h.th->fin) {
1119 *off = offset;
1120 return skb;
1121 }
1122 }
1123 return NULL;
1124 }
1125
1126 /*
1127 * This routine provides an alternative to tcp_recvmsg() for routines
1128 * that would like to handle copying from skbuffs directly in 'sendfile'
1129 * fashion.
1130 * Note:
1131 * - It is assumed that the socket was locked by the caller.
1132 * - The routine does not block.
1133 * - At present, there is no support for reading OOB data
1134 * or for 'peeking' the socket using this routine
1135 * (although both would be easy to implement).
1136 */
1137 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1138 sk_read_actor_t recv_actor)
1139 {
1140 struct sk_buff *skb;
1141 struct tcp_sock *tp = tcp_sk(sk);
1142 u32 seq = tp->copied_seq;
1143 u32 offset;
1144 int copied = 0;
1145
1146 if (sk->sk_state == TCP_LISTEN)
1147 return -ENOTCONN;
1148 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1149 if (offset < skb->len) {
1150 size_t used, len;
1151
1152 len = skb->len - offset;
1153 /* Stop reading if we hit a patch of urgent data */
1154 if (tp->urg_data) {
1155 u32 urg_offset = tp->urg_seq - seq;
1156 if (urg_offset < len)
1157 len = urg_offset;
1158 if (!len)
1159 break;
1160 }
1161 used = recv_actor(desc, skb, offset, len);
1162 if (used <= len) {
1163 seq += used;
1164 copied += used;
1165 offset += used;
1166 }
1167 if (offset != skb->len)
1168 break;
1169 }
1170 if (skb->h.th->fin) {
1171 sk_eat_skb(sk, skb);
1172 ++seq;
1173 break;
1174 }
1175 sk_eat_skb(sk, skb);
1176 if (!desc->count)
1177 break;
1178 }
1179 tp->copied_seq = seq;
1180
1181 tcp_rcv_space_adjust(sk);
1182
1183 /* Clean up data we have read: This will do ACK frames. */
1184 if (copied)
1185 cleanup_rbuf(sk, copied);
1186 return copied;
1187 }
1188
1189 /*
1190 * This routine copies from a sock struct into the user buffer.
1191 *
1192 * Technical note: in 2.3 we work on _locked_ socket, so that
1193 * tricks with *seq access order and skb->users are not required.
1194 * Probably, code can be easily improved even more.
1195 */
1196
1197 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1198 size_t len, int nonblock, int flags, int *addr_len)
1199 {
1200 struct tcp_sock *tp = tcp_sk(sk);
1201 int copied = 0;
1202 u32 peek_seq;
1203 u32 *seq;
1204 unsigned long used;
1205 int err;
1206 int target; /* Read at least this many bytes */
1207 long timeo;
1208 struct task_struct *user_recv = NULL;
1209
1210 lock_sock(sk);
1211
1212 TCP_CHECK_TIMER(sk);
1213
1214 err = -ENOTCONN;
1215 if (sk->sk_state == TCP_LISTEN)
1216 goto out;
1217
1218 timeo = sock_rcvtimeo(sk, nonblock);
1219
1220 /* Urgent data needs to be handled specially. */
1221 if (flags & MSG_OOB)
1222 goto recv_urg;
1223
1224 seq = &tp->copied_seq;
1225 if (flags & MSG_PEEK) {
1226 peek_seq = tp->copied_seq;
1227 seq = &peek_seq;
1228 }
1229
1230 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1231
1232 do {
1233 struct sk_buff *skb;
1234 u32 offset;
1235
1236 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1237 if (tp->urg_data && tp->urg_seq == *seq) {
1238 if (copied)
1239 break;
1240 if (signal_pending(current)) {
1241 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1242 break;
1243 }
1244 }
1245
1246 /* Next get a buffer. */
1247
1248 skb = skb_peek(&sk->sk_receive_queue);
1249 do {
1250 if (!skb)
1251 break;
1252
1253 /* Now that we have two receive queues this
1254 * shouldn't happen.
1255 */
1256 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1257 printk(KERN_INFO "recvmsg bug: copied %X "
1258 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1259 break;
1260 }
1261 offset = *seq - TCP_SKB_CB(skb)->seq;
1262 if (skb->h.th->syn)
1263 offset--;
1264 if (offset < skb->len)
1265 goto found_ok_skb;
1266 if (skb->h.th->fin)
1267 goto found_fin_ok;
1268 BUG_TRAP(flags & MSG_PEEK);
1269 skb = skb->next;
1270 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1271
1272 /* Well, if we have backlog, try to process it now yet. */
1273
1274 if (copied >= target && !sk->sk_backlog.tail)
1275 break;
1276
1277 if (copied) {
1278 if (sk->sk_err ||
1279 sk->sk_state == TCP_CLOSE ||
1280 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1281 !timeo ||
1282 signal_pending(current) ||
1283 (flags & MSG_PEEK))
1284 break;
1285 } else {
1286 if (sock_flag(sk, SOCK_DONE))
1287 break;
1288
1289 if (sk->sk_err) {
1290 copied = sock_error(sk);
1291 break;
1292 }
1293
1294 if (sk->sk_shutdown & RCV_SHUTDOWN)
1295 break;
1296
1297 if (sk->sk_state == TCP_CLOSE) {
1298 if (!sock_flag(sk, SOCK_DONE)) {
1299 /* This occurs when user tries to read
1300 * from never connected socket.
1301 */
1302 copied = -ENOTCONN;
1303 break;
1304 }
1305 break;
1306 }
1307
1308 if (!timeo) {
1309 copied = -EAGAIN;
1310 break;
1311 }
1312
1313 if (signal_pending(current)) {
1314 copied = sock_intr_errno(timeo);
1315 break;
1316 }
1317 }
1318
1319 cleanup_rbuf(sk, copied);
1320
1321 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1322 /* Install new reader */
1323 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1324 user_recv = current;
1325 tp->ucopy.task = user_recv;
1326 tp->ucopy.iov = msg->msg_iov;
1327 }
1328
1329 tp->ucopy.len = len;
1330
1331 BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1332 (flags & (MSG_PEEK | MSG_TRUNC)));
1333
1334 /* Ugly... If prequeue is not empty, we have to
1335 * process it before releasing socket, otherwise
1336 * order will be broken at second iteration.
1337 * More elegant solution is required!!!
1338 *
1339 * Look: we have the following (pseudo)queues:
1340 *
1341 * 1. packets in flight
1342 * 2. backlog
1343 * 3. prequeue
1344 * 4. receive_queue
1345 *
1346 * Each queue can be processed only if the next ones
1347 * are empty. At this point we have empty receive_queue.
1348 * But prequeue _can_ be not empty after 2nd iteration,
1349 * when we jumped to start of loop because backlog
1350 * processing added something to receive_queue.
1351 * We cannot release_sock(), because backlog contains
1352 * packets arrived _after_ prequeued ones.
1353 *
1354 * Shortly, algorithm is clear --- to process all
1355 * the queues in order. We could make it more directly,
1356 * requeueing packets from backlog to prequeue, if
1357 * is not empty. It is more elegant, but eats cycles,
1358 * unfortunately.
1359 */
1360 if (!skb_queue_empty(&tp->ucopy.prequeue))
1361 goto do_prequeue;
1362
1363 /* __ Set realtime policy in scheduler __ */
1364 }
1365
1366 if (copied >= target) {
1367 /* Do not sleep, just process backlog. */
1368 release_sock(sk);
1369 lock_sock(sk);
1370 } else
1371 sk_wait_data(sk, &timeo);
1372
1373 if (user_recv) {
1374 int chunk;
1375
1376 /* __ Restore normal policy in scheduler __ */
1377
1378 if ((chunk = len - tp->ucopy.len) != 0) {
1379 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1380 len -= chunk;
1381 copied += chunk;
1382 }
1383
1384 if (tp->rcv_nxt == tp->copied_seq &&
1385 !skb_queue_empty(&tp->ucopy.prequeue)) {
1386 do_prequeue:
1387 tcp_prequeue_process(sk);
1388
1389 if ((chunk = len - tp->ucopy.len) != 0) {
1390 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1391 len -= chunk;
1392 copied += chunk;
1393 }
1394 }
1395 }
1396 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1397 if (net_ratelimit())
1398 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1399 current->comm, current->pid);
1400 peek_seq = tp->copied_seq;
1401 }
1402 continue;
1403
1404 found_ok_skb:
1405 /* Ok so how much can we use? */
1406 used = skb->len - offset;
1407 if (len < used)
1408 used = len;
1409
1410 /* Do we have urgent data here? */
1411 if (tp->urg_data) {
1412 u32 urg_offset = tp->urg_seq - *seq;
1413 if (urg_offset < used) {
1414 if (!urg_offset) {
1415 if (!sock_flag(sk, SOCK_URGINLINE)) {
1416 ++*seq;
1417 offset++;
1418 used--;
1419 if (!used)
1420 goto skip_copy;
1421 }
1422 } else
1423 used = urg_offset;
1424 }
1425 }
1426
1427 if (!(flags & MSG_TRUNC)) {
1428 err = skb_copy_datagram_iovec(skb, offset,
1429 msg->msg_iov, used);
1430 if (err) {
1431 /* Exception. Bailout! */
1432 if (!copied)
1433 copied = -EFAULT;
1434 break;
1435 }
1436 }
1437
1438 *seq += used;
1439 copied += used;
1440 len -= used;
1441
1442 tcp_rcv_space_adjust(sk);
1443
1444 skip_copy:
1445 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1446 tp->urg_data = 0;
1447 tcp_fast_path_check(sk, tp);
1448 }
1449 if (used + offset < skb->len)
1450 continue;
1451
1452 if (skb->h.th->fin)
1453 goto found_fin_ok;
1454 if (!(flags & MSG_PEEK))
1455 sk_eat_skb(sk, skb);
1456 continue;
1457
1458 found_fin_ok:
1459 /* Process the FIN. */
1460 ++*seq;
1461 if (!(flags & MSG_PEEK))
1462 sk_eat_skb(sk, skb);
1463 break;
1464 } while (len > 0);
1465
1466 if (user_recv) {
1467 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1468 int chunk;
1469
1470 tp->ucopy.len = copied > 0 ? len : 0;
1471
1472 tcp_prequeue_process(sk);
1473
1474 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1475 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1476 len -= chunk;
1477 copied += chunk;
1478 }
1479 }
1480
1481 tp->ucopy.task = NULL;
1482 tp->ucopy.len = 0;
1483 }
1484
1485 /* According to UNIX98, msg_name/msg_namelen are ignored
1486 * on connected socket. I was just happy when found this 8) --ANK
1487 */
1488
1489 /* Clean up data we have read: This will do ACK frames. */
1490 cleanup_rbuf(sk, copied);
1491
1492 TCP_CHECK_TIMER(sk);
1493 release_sock(sk);
1494 return copied;
1495
1496 out:
1497 TCP_CHECK_TIMER(sk);
1498 release_sock(sk);
1499 return err;
1500
1501 recv_urg:
1502 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1503 goto out;
1504 }
1505
1506 /*
1507 * State processing on a close. This implements the state shift for
1508 * sending our FIN frame. Note that we only send a FIN for some
1509 * states. A shutdown() may have already sent the FIN, or we may be
1510 * closed.
1511 */
1512
1513 static unsigned char new_state[16] = {
1514 /* current state: new state: action: */
1515 /* (Invalid) */ TCP_CLOSE,
1516 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1517 /* TCP_SYN_SENT */ TCP_CLOSE,
1518 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1519 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1520 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1521 /* TCP_TIME_WAIT */ TCP_CLOSE,
1522 /* TCP_CLOSE */ TCP_CLOSE,
1523 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1524 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1525 /* TCP_LISTEN */ TCP_CLOSE,
1526 /* TCP_CLOSING */ TCP_CLOSING,
1527 };
1528
1529 static int tcp_close_state(struct sock *sk)
1530 {
1531 int next = (int)new_state[sk->sk_state];
1532 int ns = next & TCP_STATE_MASK;
1533
1534 tcp_set_state(sk, ns);
1535
1536 return next & TCP_ACTION_FIN;
1537 }
1538
1539 /*
1540 * Shutdown the sending side of a connection. Much like close except
1541 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1542 */
1543
1544 void tcp_shutdown(struct sock *sk, int how)
1545 {
1546 /* We need to grab some memory, and put together a FIN,
1547 * and then put it into the queue to be sent.
1548 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1549 */
1550 if (!(how & SEND_SHUTDOWN))
1551 return;
1552
1553 /* If we've already sent a FIN, or it's a closed state, skip this. */
1554 if ((1 << sk->sk_state) &
1555 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1556 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1557 /* Clear out any half completed packets. FIN if needed. */
1558 if (tcp_close_state(sk))
1559 tcp_send_fin(sk);
1560 }
1561 }
1562
1563 /*
1564 * At this point, there should be no process reference to this
1565 * socket, and thus no user references at all. Therefore we
1566 * can assume the socket waitqueue is inactive and nobody will
1567 * try to jump onto it.
1568 */
1569 void tcp_destroy_sock(struct sock *sk)
1570 {
1571 BUG_TRAP(sk->sk_state == TCP_CLOSE);
1572 BUG_TRAP(sock_flag(sk, SOCK_DEAD));
1573
1574 /* It cannot be in hash table! */
1575 BUG_TRAP(sk_unhashed(sk));
1576
1577 /* If it has not 0 inet_sk(sk)->num, it must be bound */
1578 BUG_TRAP(!inet_sk(sk)->num || inet_sk(sk)->bind_hash);
1579
1580 sk->sk_prot->destroy(sk);
1581
1582 sk_stream_kill_queues(sk);
1583
1584 xfrm_sk_free_policy(sk);
1585
1586 sk_refcnt_debug_release(sk);
1587
1588 atomic_dec(&tcp_orphan_count);
1589 sock_put(sk);
1590 }
1591
1592 void tcp_close(struct sock *sk, long timeout)
1593 {
1594 struct sk_buff *skb;
1595 int data_was_unread = 0;
1596
1597 lock_sock(sk);
1598 sk->sk_shutdown = SHUTDOWN_MASK;
1599
1600 if (sk->sk_state == TCP_LISTEN) {
1601 tcp_set_state(sk, TCP_CLOSE);
1602
1603 /* Special case. */
1604 tcp_listen_stop(sk);
1605
1606 goto adjudge_to_death;
1607 }
1608
1609 /* We need to flush the recv. buffs. We do this only on the
1610 * descriptor close, not protocol-sourced closes, because the
1611 * reader process may not have drained the data yet!
1612 */
1613 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1614 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1615 skb->h.th->fin;
1616 data_was_unread += len;
1617 __kfree_skb(skb);
1618 }
1619
1620 sk_stream_mem_reclaim(sk);
1621
1622 /* As outlined in draft-ietf-tcpimpl-prob-03.txt, section
1623 * 3.10, we send a RST here because data was lost. To
1624 * witness the awful effects of the old behavior of always
1625 * doing a FIN, run an older 2.1.x kernel or 2.0.x, start
1626 * a bulk GET in an FTP client, suspend the process, wait
1627 * for the client to advertise a zero window, then kill -9
1628 * the FTP client, wheee... Note: timeout is always zero
1629 * in such a case.
1630 */
1631 if (data_was_unread) {
1632 /* Unread data was tossed, zap the connection. */
1633 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1634 tcp_set_state(sk, TCP_CLOSE);
1635 tcp_send_active_reset(sk, GFP_KERNEL);
1636 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1637 /* Check zero linger _after_ checking for unread data. */
1638 sk->sk_prot->disconnect(sk, 0);
1639 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1640 } else if (tcp_close_state(sk)) {
1641 /* We FIN if the application ate all the data before
1642 * zapping the connection.
1643 */
1644
1645 /* RED-PEN. Formally speaking, we have broken TCP state
1646 * machine. State transitions:
1647 *
1648 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1649 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1650 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1651 *
1652 * are legal only when FIN has been sent (i.e. in window),
1653 * rather than queued out of window. Purists blame.
1654 *
1655 * F.e. "RFC state" is ESTABLISHED,
1656 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1657 *
1658 * The visible declinations are that sometimes
1659 * we enter time-wait state, when it is not required really
1660 * (harmless), do not send active resets, when they are
1661 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1662 * they look as CLOSING or LAST_ACK for Linux)
1663 * Probably, I missed some more holelets.
1664 * --ANK
1665 */
1666 tcp_send_fin(sk);
1667 }
1668
1669 sk_stream_wait_close(sk, timeout);
1670
1671 adjudge_to_death:
1672 /* It is the last release_sock in its life. It will remove backlog. */
1673 release_sock(sk);
1674
1675
1676 /* Now socket is owned by kernel and we acquire BH lock
1677 to finish close. No need to check for user refs.
1678 */
1679 local_bh_disable();
1680 bh_lock_sock(sk);
1681 BUG_TRAP(!sock_owned_by_user(sk));
1682
1683 sock_hold(sk);
1684 sock_orphan(sk);
1685
1686 /* This is a (useful) BSD violating of the RFC. There is a
1687 * problem with TCP as specified in that the other end could
1688 * keep a socket open forever with no application left this end.
1689 * We use a 3 minute timeout (about the same as BSD) then kill
1690 * our end. If they send after that then tough - BUT: long enough
1691 * that we won't make the old 4*rto = almost no time - whoops
1692 * reset mistake.
1693 *
1694 * Nope, it was not mistake. It is really desired behaviour
1695 * f.e. on http servers, when such sockets are useless, but
1696 * consume significant resources. Let's do it with special
1697 * linger2 option. --ANK
1698 */
1699
1700 if (sk->sk_state == TCP_FIN_WAIT2) {
1701 struct tcp_sock *tp = tcp_sk(sk);
1702 if (tp->linger2 < 0) {
1703 tcp_set_state(sk, TCP_CLOSE);
1704 tcp_send_active_reset(sk, GFP_ATOMIC);
1705 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1706 } else {
1707 int tmo = tcp_fin_time(tp);
1708
1709 if (tmo > TCP_TIMEWAIT_LEN) {
1710 tcp_reset_keepalive_timer(sk, tcp_fin_time(tp));
1711 } else {
1712 atomic_inc(&tcp_orphan_count);
1713 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1714 goto out;
1715 }
1716 }
1717 }
1718 if (sk->sk_state != TCP_CLOSE) {
1719 sk_stream_mem_reclaim(sk);
1720 if (atomic_read(&tcp_orphan_count) > sysctl_tcp_max_orphans ||
1721 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
1722 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) {
1723 if (net_ratelimit())
1724 printk(KERN_INFO "TCP: too many of orphaned "
1725 "sockets\n");
1726 tcp_set_state(sk, TCP_CLOSE);
1727 tcp_send_active_reset(sk, GFP_ATOMIC);
1728 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1729 }
1730 }
1731 atomic_inc(&tcp_orphan_count);
1732
1733 if (sk->sk_state == TCP_CLOSE)
1734 tcp_destroy_sock(sk);
1735 /* Otherwise, socket is reprieved until protocol close. */
1736
1737 out:
1738 bh_unlock_sock(sk);
1739 local_bh_enable();
1740 sock_put(sk);
1741 }
1742
1743 /* These states need RST on ABORT according to RFC793 */
1744
1745 static inline int tcp_need_reset(int state)
1746 {
1747 return (1 << state) &
1748 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1749 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1750 }
1751
1752 int tcp_disconnect(struct sock *sk, int flags)
1753 {
1754 struct inet_sock *inet = inet_sk(sk);
1755 struct tcp_sock *tp = tcp_sk(sk);
1756 int err = 0;
1757 int old_state = sk->sk_state;
1758
1759 if (old_state != TCP_CLOSE)
1760 tcp_set_state(sk, TCP_CLOSE);
1761
1762 /* ABORT function of RFC793 */
1763 if (old_state == TCP_LISTEN) {
1764 tcp_listen_stop(sk);
1765 } else if (tcp_need_reset(old_state) ||
1766 (tp->snd_nxt != tp->write_seq &&
1767 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1768 /* The last check adjusts for discrepance of Linux wrt. RFC
1769 * states
1770 */
1771 tcp_send_active_reset(sk, gfp_any());
1772 sk->sk_err = ECONNRESET;
1773 } else if (old_state == TCP_SYN_SENT)
1774 sk->sk_err = ECONNRESET;
1775
1776 tcp_clear_xmit_timers(sk);
1777 __skb_queue_purge(&sk->sk_receive_queue);
1778 sk_stream_writequeue_purge(sk);
1779 __skb_queue_purge(&tp->out_of_order_queue);
1780
1781 inet->dport = 0;
1782
1783 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1784 inet_reset_saddr(sk);
1785
1786 sk->sk_shutdown = 0;
1787 sock_reset_flag(sk, SOCK_DONE);
1788 tp->srtt = 0;
1789 if ((tp->write_seq += tp->max_window + 2) == 0)
1790 tp->write_seq = 1;
1791 tp->backoff = 0;
1792 tp->snd_cwnd = 2;
1793 tp->probes_out = 0;
1794 tp->packets_out = 0;
1795 tp->snd_ssthresh = 0x7fffffff;
1796 tp->snd_cwnd_cnt = 0;
1797 tcp_set_ca_state(tp, TCP_CA_Open);
1798 tcp_clear_retrans(tp);
1799 tcp_delack_init(tp);
1800 sk->sk_send_head = NULL;
1801 tp->rx_opt.saw_tstamp = 0;
1802 tcp_sack_reset(&tp->rx_opt);
1803 __sk_dst_reset(sk);
1804
1805 BUG_TRAP(!inet->num || inet->bind_hash);
1806
1807 sk->sk_error_report(sk);
1808 return err;
1809 }
1810
1811 /*
1812 * Wait for an incoming connection, avoid race
1813 * conditions. This must be called with the socket locked.
1814 */
1815 static int wait_for_connect(struct sock *sk, long timeo)
1816 {
1817 struct tcp_sock *tp = tcp_sk(sk);
1818 DEFINE_WAIT(wait);
1819 int err;
1820
1821 /*
1822 * True wake-one mechanism for incoming connections: only
1823 * one process gets woken up, not the 'whole herd'.
1824 * Since we do not 'race & poll' for established sockets
1825 * anymore, the common case will execute the loop only once.
1826 *
1827 * Subtle issue: "add_wait_queue_exclusive()" will be added
1828 * after any current non-exclusive waiters, and we know that
1829 * it will always _stay_ after any new non-exclusive waiters
1830 * because all non-exclusive waiters are added at the
1831 * beginning of the wait-queue. As such, it's ok to "drop"
1832 * our exclusiveness temporarily when we get woken up without
1833 * having to remove and re-insert us on the wait queue.
1834 */
1835 for (;;) {
1836 prepare_to_wait_exclusive(sk->sk_sleep, &wait,
1837 TASK_INTERRUPTIBLE);
1838 release_sock(sk);
1839 if (reqsk_queue_empty(&tp->accept_queue))
1840 timeo = schedule_timeout(timeo);
1841 lock_sock(sk);
1842 err = 0;
1843 if (!reqsk_queue_empty(&tp->accept_queue))
1844 break;
1845 err = -EINVAL;
1846 if (sk->sk_state != TCP_LISTEN)
1847 break;
1848 err = sock_intr_errno(timeo);
1849 if (signal_pending(current))
1850 break;
1851 err = -EAGAIN;
1852 if (!timeo)
1853 break;
1854 }
1855 finish_wait(sk->sk_sleep, &wait);
1856 return err;
1857 }
1858
1859 /*
1860 * This will accept the next outstanding connection.
1861 */
1862
1863 struct sock *tcp_accept(struct sock *sk, int flags, int *err)
1864 {
1865 struct tcp_sock *tp = tcp_sk(sk);
1866 struct sock *newsk;
1867 int error;
1868
1869 lock_sock(sk);
1870
1871 /* We need to make sure that this socket is listening,
1872 * and that it has something pending.
1873 */
1874 error = -EINVAL;
1875 if (sk->sk_state != TCP_LISTEN)
1876 goto out_err;
1877
1878 /* Find already established connection */
1879 if (reqsk_queue_empty(&tp->accept_queue)) {
1880 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
1881
1882 /* If this is a non blocking socket don't sleep */
1883 error = -EAGAIN;
1884 if (!timeo)
1885 goto out_err;
1886
1887 error = wait_for_connect(sk, timeo);
1888 if (error)
1889 goto out_err;
1890 }
1891
1892 newsk = reqsk_queue_get_child(&tp->accept_queue, sk);
1893 BUG_TRAP(newsk->sk_state != TCP_SYN_RECV);
1894 out:
1895 release_sock(sk);
1896 return newsk;
1897 out_err:
1898 newsk = NULL;
1899 *err = error;
1900 goto out;
1901 }
1902
1903 /*
1904 * Socket option code for TCP.
1905 */
1906 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
1907 int optlen)
1908 {
1909 struct tcp_sock *tp = tcp_sk(sk);
1910 int val;
1911 int err = 0;
1912
1913 if (level != SOL_TCP)
1914 return tp->af_specific->setsockopt(sk, level, optname,
1915 optval, optlen);
1916
1917 /* This is a string value all the others are int's */
1918 if (optname == TCP_CONGESTION) {
1919 char name[TCP_CA_NAME_MAX];
1920
1921 if (optlen < 1)
1922 return -EINVAL;
1923
1924 val = strncpy_from_user(name, optval,
1925 min(TCP_CA_NAME_MAX-1, optlen));
1926 if (val < 0)
1927 return -EFAULT;
1928 name[val] = 0;
1929
1930 lock_sock(sk);
1931 err = tcp_set_congestion_control(tp, name);
1932 release_sock(sk);
1933 return err;
1934 }
1935
1936 if (optlen < sizeof(int))
1937 return -EINVAL;
1938
1939 if (get_user(val, (int __user *)optval))
1940 return -EFAULT;
1941
1942 lock_sock(sk);
1943
1944 switch (optname) {
1945 case TCP_MAXSEG:
1946 /* Values greater than interface MTU won't take effect. However
1947 * at the point when this call is done we typically don't yet
1948 * know which interface is going to be used */
1949 if (val < 8 || val > MAX_TCP_WINDOW) {
1950 err = -EINVAL;
1951 break;
1952 }
1953 tp->rx_opt.user_mss = val;
1954 break;
1955
1956 case TCP_NODELAY:
1957 if (val) {
1958 /* TCP_NODELAY is weaker than TCP_CORK, so that
1959 * this option on corked socket is remembered, but
1960 * it is not activated until cork is cleared.
1961 *
1962 * However, when TCP_NODELAY is set we make
1963 * an explicit push, which overrides even TCP_CORK
1964 * for currently queued segments.
1965 */
1966 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
1967 tcp_push_pending_frames(sk, tp);
1968 } else {
1969 tp->nonagle &= ~TCP_NAGLE_OFF;
1970 }
1971 break;
1972
1973 case TCP_CORK:
1974 /* When set indicates to always queue non-full frames.
1975 * Later the user clears this option and we transmit
1976 * any pending partial frames in the queue. This is
1977 * meant to be used alongside sendfile() to get properly
1978 * filled frames when the user (for example) must write
1979 * out headers with a write() call first and then use
1980 * sendfile to send out the data parts.
1981 *
1982 * TCP_CORK can be set together with TCP_NODELAY and it is
1983 * stronger than TCP_NODELAY.
1984 */
1985 if (val) {
1986 tp->nonagle |= TCP_NAGLE_CORK;
1987 } else {
1988 tp->nonagle &= ~TCP_NAGLE_CORK;
1989 if (tp->nonagle&TCP_NAGLE_OFF)
1990 tp->nonagle |= TCP_NAGLE_PUSH;
1991 tcp_push_pending_frames(sk, tp);
1992 }
1993 break;
1994
1995 case TCP_KEEPIDLE:
1996 if (val < 1 || val > MAX_TCP_KEEPIDLE)
1997 err = -EINVAL;
1998 else {
1999 tp->keepalive_time = val * HZ;
2000 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2001 !((1 << sk->sk_state) &
2002 (TCPF_CLOSE | TCPF_LISTEN))) {
2003 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2004 if (tp->keepalive_time > elapsed)
2005 elapsed = tp->keepalive_time - elapsed;
2006 else
2007 elapsed = 0;
2008 tcp_reset_keepalive_timer(sk, elapsed);
2009 }
2010 }
2011 break;
2012 case TCP_KEEPINTVL:
2013 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2014 err = -EINVAL;
2015 else
2016 tp->keepalive_intvl = val * HZ;
2017 break;
2018 case TCP_KEEPCNT:
2019 if (val < 1 || val > MAX_TCP_KEEPCNT)
2020 err = -EINVAL;
2021 else
2022 tp->keepalive_probes = val;
2023 break;
2024 case TCP_SYNCNT:
2025 if (val < 1 || val > MAX_TCP_SYNCNT)
2026 err = -EINVAL;
2027 else
2028 tp->syn_retries = val;
2029 break;
2030
2031 case TCP_LINGER2:
2032 if (val < 0)
2033 tp->linger2 = -1;
2034 else if (val > sysctl_tcp_fin_timeout / HZ)
2035 tp->linger2 = 0;
2036 else
2037 tp->linger2 = val * HZ;
2038 break;
2039
2040 case TCP_DEFER_ACCEPT:
2041 tp->defer_accept = 0;
2042 if (val > 0) {
2043 /* Translate value in seconds to number of
2044 * retransmits */
2045 while (tp->defer_accept < 32 &&
2046 val > ((TCP_TIMEOUT_INIT / HZ) <<
2047 tp->defer_accept))
2048 tp->defer_accept++;
2049 tp->defer_accept++;
2050 }
2051 break;
2052
2053 case TCP_WINDOW_CLAMP:
2054 if (!val) {
2055 if (sk->sk_state != TCP_CLOSE) {
2056 err = -EINVAL;
2057 break;
2058 }
2059 tp->window_clamp = 0;
2060 } else
2061 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2062 SOCK_MIN_RCVBUF / 2 : val;
2063 break;
2064
2065 case TCP_QUICKACK:
2066 if (!val) {
2067 tp->ack.pingpong = 1;
2068 } else {
2069 tp->ack.pingpong = 0;
2070 if ((1 << sk->sk_state) &
2071 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2072 tcp_ack_scheduled(tp)) {
2073 tp->ack.pending |= TCP_ACK_PUSHED;
2074 cleanup_rbuf(sk, 1);
2075 if (!(val & 1))
2076 tp->ack.pingpong = 1;
2077 }
2078 }
2079 break;
2080
2081 default:
2082 err = -ENOPROTOOPT;
2083 break;
2084 };
2085 release_sock(sk);
2086 return err;
2087 }
2088
2089 /* Return information about state of tcp endpoint in API format. */
2090 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2091 {
2092 struct tcp_sock *tp = tcp_sk(sk);
2093 u32 now = tcp_time_stamp;
2094
2095 memset(info, 0, sizeof(*info));
2096
2097 info->tcpi_state = sk->sk_state;
2098 info->tcpi_ca_state = tp->ca_state;
2099 info->tcpi_retransmits = tp->retransmits;
2100 info->tcpi_probes = tp->probes_out;
2101 info->tcpi_backoff = tp->backoff;
2102
2103 if (tp->rx_opt.tstamp_ok)
2104 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2105 if (tp->rx_opt.sack_ok)
2106 info->tcpi_options |= TCPI_OPT_SACK;
2107 if (tp->rx_opt.wscale_ok) {
2108 info->tcpi_options |= TCPI_OPT_WSCALE;
2109 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2110 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2111 }
2112
2113 if (tp->ecn_flags&TCP_ECN_OK)
2114 info->tcpi_options |= TCPI_OPT_ECN;
2115
2116 info->tcpi_rto = jiffies_to_usecs(tp->rto);
2117 info->tcpi_ato = jiffies_to_usecs(tp->ack.ato);
2118 info->tcpi_snd_mss = tp->mss_cache;
2119 info->tcpi_rcv_mss = tp->ack.rcv_mss;
2120
2121 info->tcpi_unacked = tp->packets_out;
2122 info->tcpi_sacked = tp->sacked_out;
2123 info->tcpi_lost = tp->lost_out;
2124 info->tcpi_retrans = tp->retrans_out;
2125 info->tcpi_fackets = tp->fackets_out;
2126
2127 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2128 info->tcpi_last_data_recv = jiffies_to_msecs(now - tp->ack.lrcvtime);
2129 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2130
2131 info->tcpi_pmtu = tp->pmtu_cookie;
2132 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2133 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2134 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2135 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2136 info->tcpi_snd_cwnd = tp->snd_cwnd;
2137 info->tcpi_advmss = tp->advmss;
2138 info->tcpi_reordering = tp->reordering;
2139
2140 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2141 info->tcpi_rcv_space = tp->rcvq_space.space;
2142
2143 info->tcpi_total_retrans = tp->total_retrans;
2144 }
2145
2146 EXPORT_SYMBOL_GPL(tcp_get_info);
2147
2148 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2149 int __user *optlen)
2150 {
2151 struct tcp_sock *tp = tcp_sk(sk);
2152 int val, len;
2153
2154 if (level != SOL_TCP)
2155 return tp->af_specific->getsockopt(sk, level, optname,
2156 optval, optlen);
2157
2158 if (get_user(len, optlen))
2159 return -EFAULT;
2160
2161 len = min_t(unsigned int, len, sizeof(int));
2162
2163 if (len < 0)
2164 return -EINVAL;
2165
2166 switch (optname) {
2167 case TCP_MAXSEG:
2168 val = tp->mss_cache;
2169 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2170 val = tp->rx_opt.user_mss;
2171 break;
2172 case TCP_NODELAY:
2173 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2174 break;
2175 case TCP_CORK:
2176 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2177 break;
2178 case TCP_KEEPIDLE:
2179 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2180 break;
2181 case TCP_KEEPINTVL:
2182 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2183 break;
2184 case TCP_KEEPCNT:
2185 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2186 break;
2187 case TCP_SYNCNT:
2188 val = tp->syn_retries ? : sysctl_tcp_syn_retries;
2189 break;
2190 case TCP_LINGER2:
2191 val = tp->linger2;
2192 if (val >= 0)
2193 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2194 break;
2195 case TCP_DEFER_ACCEPT:
2196 val = !tp->defer_accept ? 0 : ((TCP_TIMEOUT_INIT / HZ) <<
2197 (tp->defer_accept - 1));
2198 break;
2199 case TCP_WINDOW_CLAMP:
2200 val = tp->window_clamp;
2201 break;
2202 case TCP_INFO: {
2203 struct tcp_info info;
2204
2205 if (get_user(len, optlen))
2206 return -EFAULT;
2207
2208 tcp_get_info(sk, &info);
2209
2210 len = min_t(unsigned int, len, sizeof(info));
2211 if (put_user(len, optlen))
2212 return -EFAULT;
2213 if (copy_to_user(optval, &info, len))
2214 return -EFAULT;
2215 return 0;
2216 }
2217 case TCP_QUICKACK:
2218 val = !tp->ack.pingpong;
2219 break;
2220
2221 case TCP_CONGESTION:
2222 if (get_user(len, optlen))
2223 return -EFAULT;
2224 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2225 if (put_user(len, optlen))
2226 return -EFAULT;
2227 if (copy_to_user(optval, tp->ca_ops->name, len))
2228 return -EFAULT;
2229 return 0;
2230 default:
2231 return -ENOPROTOOPT;
2232 };
2233
2234 if (put_user(len, optlen))
2235 return -EFAULT;
2236 if (copy_to_user(optval, &val, len))
2237 return -EFAULT;
2238 return 0;
2239 }
2240
2241
2242 extern void __skb_cb_too_small_for_tcp(int, int);
2243 extern struct tcp_congestion_ops tcp_reno;
2244
2245 static __initdata unsigned long thash_entries;
2246 static int __init set_thash_entries(char *str)
2247 {
2248 if (!str)
2249 return 0;
2250 thash_entries = simple_strtoul(str, &str, 0);
2251 return 1;
2252 }
2253 __setup("thash_entries=", set_thash_entries);
2254
2255 void __init tcp_init(void)
2256 {
2257 struct sk_buff *skb = NULL;
2258 int order, i;
2259
2260 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2261 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2262 sizeof(skb->cb));
2263
2264 tcp_bucket_cachep = kmem_cache_create("tcp_bind_bucket",
2265 sizeof(struct inet_bind_bucket),
2266 0, SLAB_HWCACHE_ALIGN,
2267 NULL, NULL);
2268 if (!tcp_bucket_cachep)
2269 panic("tcp_init: Cannot alloc tcp_bind_bucket cache.");
2270
2271 tcp_timewait_cachep = kmem_cache_create("tcp_tw_bucket",
2272 sizeof(struct tcp_tw_bucket),
2273 0, SLAB_HWCACHE_ALIGN,
2274 NULL, NULL);
2275 if (!tcp_timewait_cachep)
2276 panic("tcp_init: Cannot alloc tcp_tw_bucket cache.");
2277
2278 /* Size and allocate the main established and bind bucket
2279 * hash tables.
2280 *
2281 * The methodology is similar to that of the buffer cache.
2282 */
2283 tcp_ehash =
2284 alloc_large_system_hash("TCP established",
2285 sizeof(struct inet_ehash_bucket),
2286 thash_entries,
2287 (num_physpages >= 128 * 1024) ?
2288 (25 - PAGE_SHIFT) :
2289 (27 - PAGE_SHIFT),
2290 HASH_HIGHMEM,
2291 &tcp_ehash_size,
2292 NULL,
2293 0);
2294 tcp_ehash_size = (1 << tcp_ehash_size) >> 1;
2295 for (i = 0; i < (tcp_ehash_size << 1); i++) {
2296 rwlock_init(&tcp_ehash[i].lock);
2297 INIT_HLIST_HEAD(&tcp_ehash[i].chain);
2298 }
2299
2300 tcp_bhash =
2301 alloc_large_system_hash("TCP bind",
2302 sizeof(struct inet_bind_hashbucket),
2303 tcp_ehash_size,
2304 (num_physpages >= 128 * 1024) ?
2305 (25 - PAGE_SHIFT) :
2306 (27 - PAGE_SHIFT),
2307 HASH_HIGHMEM,
2308 &tcp_bhash_size,
2309 NULL,
2310 64 * 1024);
2311 tcp_bhash_size = 1 << tcp_bhash_size;
2312 for (i = 0; i < tcp_bhash_size; i++) {
2313 spin_lock_init(&tcp_bhash[i].lock);
2314 INIT_HLIST_HEAD(&tcp_bhash[i].chain);
2315 }
2316
2317 /* Try to be a bit smarter and adjust defaults depending
2318 * on available memory.
2319 */
2320 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2321 (tcp_bhash_size * sizeof(struct inet_bind_hashbucket));
2322 order++)
2323 ;
2324 if (order >= 4) {
2325 sysctl_local_port_range[0] = 32768;
2326 sysctl_local_port_range[1] = 61000;
2327 sysctl_tcp_max_tw_buckets = 180000;
2328 sysctl_tcp_max_orphans = 4096 << (order - 4);
2329 sysctl_max_syn_backlog = 1024;
2330 } else if (order < 3) {
2331 sysctl_local_port_range[0] = 1024 * (3 - order);
2332 sysctl_tcp_max_tw_buckets >>= (3 - order);
2333 sysctl_tcp_max_orphans >>= (3 - order);
2334 sysctl_max_syn_backlog = 128;
2335 }
2336 tcp_port_rover = sysctl_local_port_range[0] - 1;
2337
2338 sysctl_tcp_mem[0] = 768 << order;
2339 sysctl_tcp_mem[1] = 1024 << order;
2340 sysctl_tcp_mem[2] = 1536 << order;
2341
2342 if (order < 3) {
2343 sysctl_tcp_wmem[2] = 64 * 1024;
2344 sysctl_tcp_rmem[0] = PAGE_SIZE;
2345 sysctl_tcp_rmem[1] = 43689;
2346 sysctl_tcp_rmem[2] = 2 * 43689;
2347 }
2348
2349 printk(KERN_INFO "TCP: Hash tables configured "
2350 "(established %d bind %d)\n",
2351 tcp_ehash_size << 1, tcp_bhash_size);
2352
2353 tcp_register_congestion_control(&tcp_reno);
2354 }
2355
2356 EXPORT_SYMBOL(tcp_accept);
2357 EXPORT_SYMBOL(tcp_close);
2358 EXPORT_SYMBOL(tcp_destroy_sock);
2359 EXPORT_SYMBOL(tcp_disconnect);
2360 EXPORT_SYMBOL(tcp_getsockopt);
2361 EXPORT_SYMBOL(tcp_ioctl);
2362 EXPORT_SYMBOL(tcp_poll);
2363 EXPORT_SYMBOL(tcp_read_sock);
2364 EXPORT_SYMBOL(tcp_recvmsg);
2365 EXPORT_SYMBOL(tcp_sendmsg);
2366 EXPORT_SYMBOL(tcp_sendpage);
2367 EXPORT_SYMBOL(tcp_setsockopt);
2368 EXPORT_SYMBOL(tcp_shutdown);
2369 EXPORT_SYMBOL(tcp_statistics);
2370 EXPORT_SYMBOL(tcp_timewait_cachep);
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