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[PATCH] UML: tty locking
[linux-2.6/libata-dev.git] / net / ipv4 / tcp.c
blob66e9a729f6dfa87060c535d087fba0987bb44116
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/module.h>
251 #include <linux/types.h>
252 #include <linux/fcntl.h>
253 #include <linux/poll.h>
254 #include <linux/init.h>
255 #include <linux/smp_lock.h>
256 #include <linux/fs.h>
257 #include <linux/random.h>
258 #include <linux/bootmem.h>
259 #include <linux/cache.h>
260 #include <linux/err.h>
261
262 #include <net/icmp.h>
263 #include <net/tcp.h>
264 #include <net/xfrm.h>
265 #include <net/ip.h>
266 #include <net/netdma.h>
267
268 #include <asm/uaccess.h>
269 #include <asm/ioctls.h>
270
271 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
272
273 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly;
274
275 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
276
277 EXPORT_SYMBOL_GPL(tcp_orphan_count);
278
279 int sysctl_tcp_mem[3] __read_mostly;
280 int sysctl_tcp_wmem[3] __read_mostly;
281 int sysctl_tcp_rmem[3] __read_mostly;
282
283 EXPORT_SYMBOL(sysctl_tcp_mem);
284 EXPORT_SYMBOL(sysctl_tcp_rmem);
285 EXPORT_SYMBOL(sysctl_tcp_wmem);
286
287 atomic_t tcp_memory_allocated; /* Current allocated memory. */
288 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
289
290 EXPORT_SYMBOL(tcp_memory_allocated);
291 EXPORT_SYMBOL(tcp_sockets_allocated);
292
293 /*
294 * Pressure flag: try to collapse.
295 * Technical note: it is used by multiple contexts non atomically.
296 * All the sk_stream_mem_schedule() is of this nature: accounting
297 * is strict, actions are advisory and have some latency.
298 */
299 int tcp_memory_pressure;
300
301 EXPORT_SYMBOL(tcp_memory_pressure);
302
303 void tcp_enter_memory_pressure(void)
304 {
305 if (!tcp_memory_pressure) {
306 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
307 tcp_memory_pressure = 1;
308 }
309 }
310
311 EXPORT_SYMBOL(tcp_enter_memory_pressure);
312
313 /*
314 * Wait for a TCP event.
315 *
316 * Note that we don't need to lock the socket, as the upper poll layers
317 * take care of normal races (between the test and the event) and we don't
318 * go look at any of the socket buffers directly.
319 */
320 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
321 {
322 unsigned int mask;
323 struct sock *sk = sock->sk;
324 struct tcp_sock *tp = tcp_sk(sk);
325
326 poll_wait(file, sk->sk_sleep, wait);
327 if (sk->sk_state == TCP_LISTEN)
328 return inet_csk_listen_poll(sk);
329
330 /* Socket is not locked. We are protected from async events
331 by poll logic and correct handling of state changes
332 made by another threads is impossible in any case.
333 */
334
335 mask = 0;
336 if (sk->sk_err)
337 mask = POLLERR;
338
339 /*
340 * POLLHUP is certainly not done right. But poll() doesn't
341 * have a notion of HUP in just one direction, and for a
342 * socket the read side is more interesting.
343 *
344 * Some poll() documentation says that POLLHUP is incompatible
345 * with the POLLOUT/POLLWR flags, so somebody should check this
346 * all. But careful, it tends to be safer to return too many
347 * bits than too few, and you can easily break real applications
348 * if you don't tell them that something has hung up!
349 *
350 * Check-me.
351 *
352 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
353 * our fs/select.c). It means that after we received EOF,
354 * poll always returns immediately, making impossible poll() on write()
355 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
356 * if and only if shutdown has been made in both directions.
357 * Actually, it is interesting to look how Solaris and DUX
358 * solve this dilemma. I would prefer, if PULLHUP were maskable,
359 * then we could set it on SND_SHUTDOWN. BTW examples given
360 * in Stevens' books assume exactly this behaviour, it explains
361 * why PULLHUP is incompatible with POLLOUT. --ANK
362 *
363 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
364 * blocking on fresh not-connected or disconnected socket. --ANK
365 */
366 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
367 mask |= POLLHUP;
368 if (sk->sk_shutdown & RCV_SHUTDOWN)
369 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
370
371 /* Connected? */
372 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
373 /* Potential race condition. If read of tp below will
374 * escape above sk->sk_state, we can be illegally awaken
375 * in SYN_* states. */
376 if ((tp->rcv_nxt != tp->copied_seq) &&
377 (tp->urg_seq != tp->copied_seq ||
378 tp->rcv_nxt != tp->copied_seq + 1 ||
379 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
380 mask |= POLLIN | POLLRDNORM;
381
382 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
383 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
384 mask |= POLLOUT | POLLWRNORM;
385 } else { /* send SIGIO later */
386 set_bit(SOCK_ASYNC_NOSPACE,
387 &sk->sk_socket->flags);
388 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
389
390 /* Race breaker. If space is freed after
391 * wspace test but before the flags are set,
392 * IO signal will be lost.
393 */
394 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
395 mask |= POLLOUT | POLLWRNORM;
396 }
397 }
398
399 if (tp->urg_data & TCP_URG_VALID)
400 mask |= POLLPRI;
401 }
402 return mask;
403 }
404
405 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
406 {
407 struct tcp_sock *tp = tcp_sk(sk);
408 int answ;
409
410 switch (cmd) {
411 case SIOCINQ:
412 if (sk->sk_state == TCP_LISTEN)
413 return -EINVAL;
414
415 lock_sock(sk);
416 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
417 answ = 0;
418 else if (sock_flag(sk, SOCK_URGINLINE) ||
419 !tp->urg_data ||
420 before(tp->urg_seq, tp->copied_seq) ||
421 !before(tp->urg_seq, tp->rcv_nxt)) {
422 answ = tp->rcv_nxt - tp->copied_seq;
423
424 /* Subtract 1, if FIN is in queue. */
425 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
426 answ -=
427 ((struct sk_buff *)sk->sk_receive_queue.prev)->h.th->fin;
428 } else
429 answ = tp->urg_seq - tp->copied_seq;
430 release_sock(sk);
431 break;
432 case SIOCATMARK:
433 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
434 break;
435 case SIOCOUTQ:
436 if (sk->sk_state == TCP_LISTEN)
437 return -EINVAL;
438
439 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
440 answ = 0;
441 else
442 answ = tp->write_seq - tp->snd_una;
443 break;
444 default:
445 return -ENOIOCTLCMD;
446 };
447
448 return put_user(answ, (int __user *)arg);
449 }
450
451 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
452 {
453 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
454 tp->pushed_seq = tp->write_seq;
455 }
456
457 static inline int forced_push(struct tcp_sock *tp)
458 {
459 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
460 }
461
462 static inline void skb_entail(struct sock *sk, struct tcp_sock *tp,
463 struct sk_buff *skb)
464 {
465 skb->csum = 0;
466 TCP_SKB_CB(skb)->seq = tp->write_seq;
467 TCP_SKB_CB(skb)->end_seq = tp->write_seq;
468 TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
469 TCP_SKB_CB(skb)->sacked = 0;
470 skb_header_release(skb);
471 __skb_queue_tail(&sk->sk_write_queue, skb);
472 sk_charge_skb(sk, skb);
473 if (!sk->sk_send_head)
474 sk->sk_send_head = skb;
475 if (tp->nonagle & TCP_NAGLE_PUSH)
476 tp->nonagle &= ~TCP_NAGLE_PUSH;
477 }
478
479 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
480 struct sk_buff *skb)
481 {
482 if (flags & MSG_OOB) {
483 tp->urg_mode = 1;
484 tp->snd_up = tp->write_seq;
485 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
486 }
487 }
488
489 static inline void tcp_push(struct sock *sk, struct tcp_sock *tp, int flags,
490 int mss_now, int nonagle)
491 {
492 if (sk->sk_send_head) {
493 struct sk_buff *skb = sk->sk_write_queue.prev;
494 if (!(flags & MSG_MORE) || forced_push(tp))
495 tcp_mark_push(tp, skb);
496 tcp_mark_urg(tp, flags, skb);
497 __tcp_push_pending_frames(sk, tp, mss_now,
498 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
499 }
500 }
501
502 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
503 size_t psize, int flags)
504 {
505 struct tcp_sock *tp = tcp_sk(sk);
506 int mss_now, size_goal;
507 int err;
508 ssize_t copied;
509 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
510
511 /* Wait for a connection to finish. */
512 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
513 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
514 goto out_err;
515
516 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
517
518 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
519 size_goal = tp->xmit_size_goal;
520 copied = 0;
521
522 err = -EPIPE;
523 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
524 goto do_error;
525
526 while (psize > 0) {
527 struct sk_buff *skb = sk->sk_write_queue.prev;
528 struct page *page = pages[poffset / PAGE_SIZE];
529 int copy, i, can_coalesce;
530 int offset = poffset % PAGE_SIZE;
531 int size = min_t(size_t, psize, PAGE_SIZE - offset);
532
533 if (!sk->sk_send_head || (copy = size_goal - skb->len) <= 0) {
534 new_segment:
535 if (!sk_stream_memory_free(sk))
536 goto wait_for_sndbuf;
537
538 skb = sk_stream_alloc_pskb(sk, 0, 0,
539 sk->sk_allocation);
540 if (!skb)
541 goto wait_for_memory;
542
543 skb_entail(sk, tp, skb);
544 copy = size_goal;
545 }
546
547 if (copy > size)
548 copy = size;
549
550 i = skb_shinfo(skb)->nr_frags;
551 can_coalesce = skb_can_coalesce(skb, i, page, offset);
552 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
553 tcp_mark_push(tp, skb);
554 goto new_segment;
555 }
556 if (!sk_stream_wmem_schedule(sk, copy))
557 goto wait_for_memory;
558
559 if (can_coalesce) {
560 skb_shinfo(skb)->frags[i - 1].size += copy;
561 } else {
562 get_page(page);
563 skb_fill_page_desc(skb, i, page, offset, copy);
564 }
565
566 skb->len += copy;
567 skb->data_len += copy;
568 skb->truesize += copy;
569 sk->sk_wmem_queued += copy;
570 sk->sk_forward_alloc -= copy;
571 skb->ip_summed = CHECKSUM_PARTIAL;
572 tp->write_seq += copy;
573 TCP_SKB_CB(skb)->end_seq += copy;
574 skb_shinfo(skb)->gso_segs = 0;
575
576 if (!copied)
577 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
578
579 copied += copy;
580 poffset += copy;
581 if (!(psize -= copy))
582 goto out;
583
584 if (skb->len < mss_now || (flags & MSG_OOB))
585 continue;
586
587 if (forced_push(tp)) {
588 tcp_mark_push(tp, skb);
589 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
590 } else if (skb == sk->sk_send_head)
591 tcp_push_one(sk, mss_now);
592 continue;
593
594 wait_for_sndbuf:
595 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
596 wait_for_memory:
597 if (copied)
598 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
599
600 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
601 goto do_error;
602
603 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
604 size_goal = tp->xmit_size_goal;
605 }
606
607 out:
608 if (copied)
609 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
610 return copied;
611
612 do_error:
613 if (copied)
614 goto out;
615 out_err:
616 return sk_stream_error(sk, flags, err);
617 }
618
619 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
620 size_t size, int flags)
621 {
622 ssize_t res;
623 struct sock *sk = sock->sk;
624
625 if (!(sk->sk_route_caps & NETIF_F_SG) ||
626 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
627 return sock_no_sendpage(sock, page, offset, size, flags);
628
629 lock_sock(sk);
630 TCP_CHECK_TIMER(sk);
631 res = do_tcp_sendpages(sk, &page, offset, size, flags);
632 TCP_CHECK_TIMER(sk);
633 release_sock(sk);
634 return res;
635 }
636
637 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
638 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
639
640 static inline int select_size(struct sock *sk, struct tcp_sock *tp)
641 {
642 int tmp = tp->mss_cache;
643
644 if (sk->sk_route_caps & NETIF_F_SG) {
645 if (sk_can_gso(sk))
646 tmp = 0;
647 else {
648 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
649
650 if (tmp >= pgbreak &&
651 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
652 tmp = pgbreak;
653 }
654 }
655
656 return tmp;
657 }
658
659 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
660 size_t size)
661 {
662 struct iovec *iov;
663 struct tcp_sock *tp = tcp_sk(sk);
664 struct sk_buff *skb;
665 int iovlen, flags;
666 int mss_now, size_goal;
667 int err, copied;
668 long timeo;
669
670 lock_sock(sk);
671 TCP_CHECK_TIMER(sk);
672
673 flags = msg->msg_flags;
674 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
675
676 /* Wait for a connection to finish. */
677 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
678 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
679 goto out_err;
680
681 /* This should be in poll */
682 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
683
684 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
685 size_goal = tp->xmit_size_goal;
686
687 /* Ok commence sending. */
688 iovlen = msg->msg_iovlen;
689 iov = msg->msg_iov;
690 copied = 0;
691
692 err = -EPIPE;
693 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
694 goto do_error;
695
696 while (--iovlen >= 0) {
697 int seglen = iov->iov_len;
698 unsigned char __user *from = iov->iov_base;
699
700 iov++;
701
702 while (seglen > 0) {
703 int copy;
704
705 skb = sk->sk_write_queue.prev;
706
707 if (!sk->sk_send_head ||
708 (copy = size_goal - skb->len) <= 0) {
709
710 new_segment:
711 /* Allocate new segment. If the interface is SG,
712 * allocate skb fitting to single page.
713 */
714 if (!sk_stream_memory_free(sk))
715 goto wait_for_sndbuf;
716
717 skb = sk_stream_alloc_pskb(sk, select_size(sk, tp),
718 0, sk->sk_allocation);
719 if (!skb)
720 goto wait_for_memory;
721
722 /*
723 * Check whether we can use HW checksum.
724 */
725 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
726 skb->ip_summed = CHECKSUM_PARTIAL;
727
728 skb_entail(sk, tp, skb);
729 copy = size_goal;
730 }
731
732 /* Try to append data to the end of skb. */
733 if (copy > seglen)
734 copy = seglen;
735
736 /* Where to copy to? */
737 if (skb_tailroom(skb) > 0) {
738 /* We have some space in skb head. Superb! */
739 if (copy > skb_tailroom(skb))
740 copy = skb_tailroom(skb);
741 if ((err = skb_add_data(skb, from, copy)) != 0)
742 goto do_fault;
743 } else {
744 int merge = 0;
745 int i = skb_shinfo(skb)->nr_frags;
746 struct page *page = TCP_PAGE(sk);
747 int off = TCP_OFF(sk);
748
749 if (skb_can_coalesce(skb, i, page, off) &&
750 off != PAGE_SIZE) {
751 /* We can extend the last page
752 * fragment. */
753 merge = 1;
754 } else if (i == MAX_SKB_FRAGS ||
755 (!i &&
756 !(sk->sk_route_caps & NETIF_F_SG))) {
757 /* Need to add new fragment and cannot
758 * do this because interface is non-SG,
759 * or because all the page slots are
760 * busy. */
761 tcp_mark_push(tp, skb);
762 goto new_segment;
763 } else if (page) {
764 if (off == PAGE_SIZE) {
765 put_page(page);
766 TCP_PAGE(sk) = page = NULL;
767 off = 0;
768 }
769 } else
770 off = 0;
771
772 if (copy > PAGE_SIZE - off)
773 copy = PAGE_SIZE - off;
774
775 if (!sk_stream_wmem_schedule(sk, copy))
776 goto wait_for_memory;
777
778 if (!page) {
779 /* Allocate new cache page. */
780 if (!(page = sk_stream_alloc_page(sk)))
781 goto wait_for_memory;
782 }
783
784 /* Time to copy data. We are close to
785 * the end! */
786 err = skb_copy_to_page(sk, from, skb, page,
787 off, copy);
788 if (err) {
789 /* If this page was new, give it to the
790 * socket so it does not get leaked.
791 */
792 if (!TCP_PAGE(sk)) {
793 TCP_PAGE(sk) = page;
794 TCP_OFF(sk) = 0;
795 }
796 goto do_error;
797 }
798
799 /* Update the skb. */
800 if (merge) {
801 skb_shinfo(skb)->frags[i - 1].size +=
802 copy;
803 } else {
804 skb_fill_page_desc(skb, i, page, off, copy);
805 if (TCP_PAGE(sk)) {
806 get_page(page);
807 } else if (off + copy < PAGE_SIZE) {
808 get_page(page);
809 TCP_PAGE(sk) = page;
810 }
811 }
812
813 TCP_OFF(sk) = off + copy;
814 }
815
816 if (!copied)
817 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
818
819 tp->write_seq += copy;
820 TCP_SKB_CB(skb)->end_seq += copy;
821 skb_shinfo(skb)->gso_segs = 0;
822
823 from += copy;
824 copied += copy;
825 if ((seglen -= copy) == 0 && iovlen == 0)
826 goto out;
827
828 if (skb->len < mss_now || (flags & MSG_OOB))
829 continue;
830
831 if (forced_push(tp)) {
832 tcp_mark_push(tp, skb);
833 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
834 } else if (skb == sk->sk_send_head)
835 tcp_push_one(sk, mss_now);
836 continue;
837
838 wait_for_sndbuf:
839 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
840 wait_for_memory:
841 if (copied)
842 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
843
844 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
845 goto do_error;
846
847 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
848 size_goal = tp->xmit_size_goal;
849 }
850 }
851
852 out:
853 if (copied)
854 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
855 TCP_CHECK_TIMER(sk);
856 release_sock(sk);
857 return copied;
858
859 do_fault:
860 if (!skb->len) {
861 if (sk->sk_send_head == skb)
862 sk->sk_send_head = NULL;
863 __skb_unlink(skb, &sk->sk_write_queue);
864 sk_stream_free_skb(sk, skb);
865 }
866
867 do_error:
868 if (copied)
869 goto out;
870 out_err:
871 err = sk_stream_error(sk, flags, err);
872 TCP_CHECK_TIMER(sk);
873 release_sock(sk);
874 return err;
875 }
876
877 /*
878 * Handle reading urgent data. BSD has very simple semantics for
879 * this, no blocking and very strange errors 8)
880 */
881
882 static int tcp_recv_urg(struct sock *sk, long timeo,
883 struct msghdr *msg, int len, int flags,
884 int *addr_len)
885 {
886 struct tcp_sock *tp = tcp_sk(sk);
887
888 /* No URG data to read. */
889 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
890 tp->urg_data == TCP_URG_READ)
891 return -EINVAL; /* Yes this is right ! */
892
893 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
894 return -ENOTCONN;
895
896 if (tp->urg_data & TCP_URG_VALID) {
897 int err = 0;
898 char c = tp->urg_data;
899
900 if (!(flags & MSG_PEEK))
901 tp->urg_data = TCP_URG_READ;
902
903 /* Read urgent data. */
904 msg->msg_flags |= MSG_OOB;
905
906 if (len > 0) {
907 if (!(flags & MSG_TRUNC))
908 err = memcpy_toiovec(msg->msg_iov, &c, 1);
909 len = 1;
910 } else
911 msg->msg_flags |= MSG_TRUNC;
912
913 return err ? -EFAULT : len;
914 }
915
916 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
917 return 0;
918
919 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
920 * the available implementations agree in this case:
921 * this call should never block, independent of the
922 * blocking state of the socket.
923 * Mike <pall@rz.uni-karlsruhe.de>
924 */
925 return -EAGAIN;
926 }
927
928 /* Clean up the receive buffer for full frames taken by the user,
929 * then send an ACK if necessary. COPIED is the number of bytes
930 * tcp_recvmsg has given to the user so far, it speeds up the
931 * calculation of whether or not we must ACK for the sake of
932 * a window update.
933 */
934 void tcp_cleanup_rbuf(struct sock *sk, int copied)
935 {
936 struct tcp_sock *tp = tcp_sk(sk);
937 int time_to_ack = 0;
938
939 #if TCP_DEBUG
940 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
941
942 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
943 #endif
944
945 if (inet_csk_ack_scheduled(sk)) {
946 const struct inet_connection_sock *icsk = inet_csk(sk);
947 /* Delayed ACKs frequently hit locked sockets during bulk
948 * receive. */
949 if (icsk->icsk_ack.blocked ||
950 /* Once-per-two-segments ACK was not sent by tcp_input.c */
951 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
952 /*
953 * If this read emptied read buffer, we send ACK, if
954 * connection is not bidirectional, user drained
955 * receive buffer and there was a small segment
956 * in queue.
957 */
958 (copied > 0 &&
959 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
960 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
961 !icsk->icsk_ack.pingpong)) &&
962 !atomic_read(&sk->sk_rmem_alloc)))
963 time_to_ack = 1;
964 }
965
966 /* We send an ACK if we can now advertise a non-zero window
967 * which has been raised "significantly".
968 *
969 * Even if window raised up to infinity, do not send window open ACK
970 * in states, where we will not receive more. It is useless.
971 */
972 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
973 __u32 rcv_window_now = tcp_receive_window(tp);
974
975 /* Optimize, __tcp_select_window() is not cheap. */
976 if (2*rcv_window_now <= tp->window_clamp) {
977 __u32 new_window = __tcp_select_window(sk);
978
979 /* Send ACK now, if this read freed lots of space
980 * in our buffer. Certainly, new_window is new window.
981 * We can advertise it now, if it is not less than current one.
982 * "Lots" means "at least twice" here.
983 */
984 if (new_window && new_window >= 2 * rcv_window_now)
985 time_to_ack = 1;
986 }
987 }
988 if (time_to_ack)
989 tcp_send_ack(sk);
990 }
991
992 static void tcp_prequeue_process(struct sock *sk)
993 {
994 struct sk_buff *skb;
995 struct tcp_sock *tp = tcp_sk(sk);
996
997 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
998
999 /* RX process wants to run with disabled BHs, though it is not
1000 * necessary */
1001 local_bh_disable();
1002 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1003 sk->sk_backlog_rcv(sk, skb);
1004 local_bh_enable();
1005
1006 /* Clear memory counter. */
1007 tp->ucopy.memory = 0;
1008 }
1009
1010 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1011 {
1012 struct sk_buff *skb;
1013 u32 offset;
1014
1015 skb_queue_walk(&sk->sk_receive_queue, skb) {
1016 offset = seq - TCP_SKB_CB(skb)->seq;
1017 if (skb->h.th->syn)
1018 offset--;
1019 if (offset < skb->len || skb->h.th->fin) {
1020 *off = offset;
1021 return skb;
1022 }
1023 }
1024 return NULL;
1025 }
1026
1027 /*
1028 * This routine provides an alternative to tcp_recvmsg() for routines
1029 * that would like to handle copying from skbuffs directly in 'sendfile'
1030 * fashion.
1031 * Note:
1032 * - It is assumed that the socket was locked by the caller.
1033 * - The routine does not block.
1034 * - At present, there is no support for reading OOB data
1035 * or for 'peeking' the socket using this routine
1036 * (although both would be easy to implement).
1037 */
1038 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1039 sk_read_actor_t recv_actor)
1040 {
1041 struct sk_buff *skb;
1042 struct tcp_sock *tp = tcp_sk(sk);
1043 u32 seq = tp->copied_seq;
1044 u32 offset;
1045 int copied = 0;
1046
1047 if (sk->sk_state == TCP_LISTEN)
1048 return -ENOTCONN;
1049 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1050 if (offset < skb->len) {
1051 size_t used, len;
1052
1053 len = skb->len - offset;
1054 /* Stop reading if we hit a patch of urgent data */
1055 if (tp->urg_data) {
1056 u32 urg_offset = tp->urg_seq - seq;
1057 if (urg_offset < len)
1058 len = urg_offset;
1059 if (!len)
1060 break;
1061 }
1062 used = recv_actor(desc, skb, offset, len);
1063 if (used <= len) {
1064 seq += used;
1065 copied += used;
1066 offset += used;
1067 }
1068 if (offset != skb->len)
1069 break;
1070 }
1071 if (skb->h.th->fin) {
1072 sk_eat_skb(sk, skb, 0);
1073 ++seq;
1074 break;
1075 }
1076 sk_eat_skb(sk, skb, 0);
1077 if (!desc->count)
1078 break;
1079 }
1080 tp->copied_seq = seq;
1081
1082 tcp_rcv_space_adjust(sk);
1083
1084 /* Clean up data we have read: This will do ACK frames. */
1085 if (copied)
1086 tcp_cleanup_rbuf(sk, copied);
1087 return copied;
1088 }
1089
1090 /*
1091 * This routine copies from a sock struct into the user buffer.
1092 *
1093 * Technical note: in 2.3 we work on _locked_ socket, so that
1094 * tricks with *seq access order and skb->users are not required.
1095 * Probably, code can be easily improved even more.
1096 */
1097
1098 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1099 size_t len, int nonblock, int flags, int *addr_len)
1100 {
1101 struct tcp_sock *tp = tcp_sk(sk);
1102 int copied = 0;
1103 u32 peek_seq;
1104 u32 *seq;
1105 unsigned long used;
1106 int err;
1107 int target; /* Read at least this many bytes */
1108 long timeo;
1109 struct task_struct *user_recv = NULL;
1110 int copied_early = 0;
1111
1112 lock_sock(sk);
1113
1114 TCP_CHECK_TIMER(sk);
1115
1116 err = -ENOTCONN;
1117 if (sk->sk_state == TCP_LISTEN)
1118 goto out;
1119
1120 timeo = sock_rcvtimeo(sk, nonblock);
1121
1122 /* Urgent data needs to be handled specially. */
1123 if (flags & MSG_OOB)
1124 goto recv_urg;
1125
1126 seq = &tp->copied_seq;
1127 if (flags & MSG_PEEK) {
1128 peek_seq = tp->copied_seq;
1129 seq = &peek_seq;
1130 }
1131
1132 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1133
1134 #ifdef CONFIG_NET_DMA
1135 tp->ucopy.dma_chan = NULL;
1136 preempt_disable();
1137 if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1138 !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) {
1139 preempt_enable_no_resched();
1140 tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len);
1141 } else
1142 preempt_enable_no_resched();
1143 #endif
1144
1145 do {
1146 struct sk_buff *skb;
1147 u32 offset;
1148
1149 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1150 if (tp->urg_data && tp->urg_seq == *seq) {
1151 if (copied)
1152 break;
1153 if (signal_pending(current)) {
1154 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1155 break;
1156 }
1157 }
1158
1159 /* Next get a buffer. */
1160
1161 skb = skb_peek(&sk->sk_receive_queue);
1162 do {
1163 if (!skb)
1164 break;
1165
1166 /* Now that we have two receive queues this
1167 * shouldn't happen.
1168 */
1169 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1170 printk(KERN_INFO "recvmsg bug: copied %X "
1171 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1172 break;
1173 }
1174 offset = *seq - TCP_SKB_CB(skb)->seq;
1175 if (skb->h.th->syn)
1176 offset--;
1177 if (offset < skb->len)
1178 goto found_ok_skb;
1179 if (skb->h.th->fin)
1180 goto found_fin_ok;
1181 BUG_TRAP(flags & MSG_PEEK);
1182 skb = skb->next;
1183 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1184
1185 /* Well, if we have backlog, try to process it now yet. */
1186
1187 if (copied >= target && !sk->sk_backlog.tail)
1188 break;
1189
1190 if (copied) {
1191 if (sk->sk_err ||
1192 sk->sk_state == TCP_CLOSE ||
1193 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1194 !timeo ||
1195 signal_pending(current) ||
1196 (flags & MSG_PEEK))
1197 break;
1198 } else {
1199 if (sock_flag(sk, SOCK_DONE))
1200 break;
1201
1202 if (sk->sk_err) {
1203 copied = sock_error(sk);
1204 break;
1205 }
1206
1207 if (sk->sk_shutdown & RCV_SHUTDOWN)
1208 break;
1209
1210 if (sk->sk_state == TCP_CLOSE) {
1211 if (!sock_flag(sk, SOCK_DONE)) {
1212 /* This occurs when user tries to read
1213 * from never connected socket.
1214 */
1215 copied = -ENOTCONN;
1216 break;
1217 }
1218 break;
1219 }
1220
1221 if (!timeo) {
1222 copied = -EAGAIN;
1223 break;
1224 }
1225
1226 if (signal_pending(current)) {
1227 copied = sock_intr_errno(timeo);
1228 break;
1229 }
1230 }
1231
1232 tcp_cleanup_rbuf(sk, copied);
1233
1234 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1235 /* Install new reader */
1236 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1237 user_recv = current;
1238 tp->ucopy.task = user_recv;
1239 tp->ucopy.iov = msg->msg_iov;
1240 }
1241
1242 tp->ucopy.len = len;
1243
1244 BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1245 (flags & (MSG_PEEK | MSG_TRUNC)));
1246
1247 /* Ugly... If prequeue is not empty, we have to
1248 * process it before releasing socket, otherwise
1249 * order will be broken at second iteration.
1250 * More elegant solution is required!!!
1251 *
1252 * Look: we have the following (pseudo)queues:
1253 *
1254 * 1. packets in flight
1255 * 2. backlog
1256 * 3. prequeue
1257 * 4. receive_queue
1258 *
1259 * Each queue can be processed only if the next ones
1260 * are empty. At this point we have empty receive_queue.
1261 * But prequeue _can_ be not empty after 2nd iteration,
1262 * when we jumped to start of loop because backlog
1263 * processing added something to receive_queue.
1264 * We cannot release_sock(), because backlog contains
1265 * packets arrived _after_ prequeued ones.
1266 *
1267 * Shortly, algorithm is clear --- to process all
1268 * the queues in order. We could make it more directly,
1269 * requeueing packets from backlog to prequeue, if
1270 * is not empty. It is more elegant, but eats cycles,
1271 * unfortunately.
1272 */
1273 if (!skb_queue_empty(&tp->ucopy.prequeue))
1274 goto do_prequeue;
1275
1276 /* __ Set realtime policy in scheduler __ */
1277 }
1278
1279 if (copied >= target) {
1280 /* Do not sleep, just process backlog. */
1281 release_sock(sk);
1282 lock_sock(sk);
1283 } else
1284 sk_wait_data(sk, &timeo);
1285
1286 #ifdef CONFIG_NET_DMA
1287 tp->ucopy.wakeup = 0;
1288 #endif
1289
1290 if (user_recv) {
1291 int chunk;
1292
1293 /* __ Restore normal policy in scheduler __ */
1294
1295 if ((chunk = len - tp->ucopy.len) != 0) {
1296 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1297 len -= chunk;
1298 copied += chunk;
1299 }
1300
1301 if (tp->rcv_nxt == tp->copied_seq &&
1302 !skb_queue_empty(&tp->ucopy.prequeue)) {
1303 do_prequeue:
1304 tcp_prequeue_process(sk);
1305
1306 if ((chunk = len - tp->ucopy.len) != 0) {
1307 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1308 len -= chunk;
1309 copied += chunk;
1310 }
1311 }
1312 }
1313 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1314 if (net_ratelimit())
1315 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1316 current->comm, current->pid);
1317 peek_seq = tp->copied_seq;
1318 }
1319 continue;
1320
1321 found_ok_skb:
1322 /* Ok so how much can we use? */
1323 used = skb->len - offset;
1324 if (len < used)
1325 used = len;
1326
1327 /* Do we have urgent data here? */
1328 if (tp->urg_data) {
1329 u32 urg_offset = tp->urg_seq - *seq;
1330 if (urg_offset < used) {
1331 if (!urg_offset) {
1332 if (!sock_flag(sk, SOCK_URGINLINE)) {
1333 ++*seq;
1334 offset++;
1335 used--;
1336 if (!used)
1337 goto skip_copy;
1338 }
1339 } else
1340 used = urg_offset;
1341 }
1342 }
1343
1344 if (!(flags & MSG_TRUNC)) {
1345 #ifdef CONFIG_NET_DMA
1346 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1347 tp->ucopy.dma_chan = get_softnet_dma();
1348
1349 if (tp->ucopy.dma_chan) {
1350 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1351 tp->ucopy.dma_chan, skb, offset,
1352 msg->msg_iov, used,
1353 tp->ucopy.pinned_list);
1354
1355 if (tp->ucopy.dma_cookie < 0) {
1356
1357 printk(KERN_ALERT "dma_cookie < 0\n");
1358
1359 /* Exception. Bailout! */
1360 if (!copied)
1361 copied = -EFAULT;
1362 break;
1363 }
1364 if ((offset + used) == skb->len)
1365 copied_early = 1;
1366
1367 } else
1368 #endif
1369 {
1370 err = skb_copy_datagram_iovec(skb, offset,
1371 msg->msg_iov, used);
1372 if (err) {
1373 /* Exception. Bailout! */
1374 if (!copied)
1375 copied = -EFAULT;
1376 break;
1377 }
1378 }
1379 }
1380
1381 *seq += used;
1382 copied += used;
1383 len -= used;
1384
1385 tcp_rcv_space_adjust(sk);
1386
1387 skip_copy:
1388 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1389 tp->urg_data = 0;
1390 tcp_fast_path_check(sk, tp);
1391 }
1392 if (used + offset < skb->len)
1393 continue;
1394
1395 if (skb->h.th->fin)
1396 goto found_fin_ok;
1397 if (!(flags & MSG_PEEK)) {
1398 sk_eat_skb(sk, skb, copied_early);
1399 copied_early = 0;
1400 }
1401 continue;
1402
1403 found_fin_ok:
1404 /* Process the FIN. */
1405 ++*seq;
1406 if (!(flags & MSG_PEEK)) {
1407 sk_eat_skb(sk, skb, copied_early);
1408 copied_early = 0;
1409 }
1410 break;
1411 } while (len > 0);
1412
1413 if (user_recv) {
1414 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1415 int chunk;
1416
1417 tp->ucopy.len = copied > 0 ? len : 0;
1418
1419 tcp_prequeue_process(sk);
1420
1421 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1422 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1423 len -= chunk;
1424 copied += chunk;
1425 }
1426 }
1427
1428 tp->ucopy.task = NULL;
1429 tp->ucopy.len = 0;
1430 }
1431
1432 #ifdef CONFIG_NET_DMA
1433 if (tp->ucopy.dma_chan) {
1434 struct sk_buff *skb;
1435 dma_cookie_t done, used;
1436
1437 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1438
1439 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1440 tp->ucopy.dma_cookie, &done,
1441 &used) == DMA_IN_PROGRESS) {
1442 /* do partial cleanup of sk_async_wait_queue */
1443 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1444 (dma_async_is_complete(skb->dma_cookie, done,
1445 used) == DMA_SUCCESS)) {
1446 __skb_dequeue(&sk->sk_async_wait_queue);
1447 kfree_skb(skb);
1448 }
1449 }
1450
1451 /* Safe to free early-copied skbs now */
1452 __skb_queue_purge(&sk->sk_async_wait_queue);
1453 dma_chan_put(tp->ucopy.dma_chan);
1454 tp->ucopy.dma_chan = NULL;
1455 }
1456 if (tp->ucopy.pinned_list) {
1457 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1458 tp->ucopy.pinned_list = NULL;
1459 }
1460 #endif
1461
1462 /* According to UNIX98, msg_name/msg_namelen are ignored
1463 * on connected socket. I was just happy when found this 8) --ANK
1464 */
1465
1466 /* Clean up data we have read: This will do ACK frames. */
1467 tcp_cleanup_rbuf(sk, copied);
1468
1469 TCP_CHECK_TIMER(sk);
1470 release_sock(sk);
1471 return copied;
1472
1473 out:
1474 TCP_CHECK_TIMER(sk);
1475 release_sock(sk);
1476 return err;
1477
1478 recv_urg:
1479 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1480 goto out;
1481 }
1482
1483 /*
1484 * State processing on a close. This implements the state shift for
1485 * sending our FIN frame. Note that we only send a FIN for some
1486 * states. A shutdown() may have already sent the FIN, or we may be
1487 * closed.
1488 */
1489
1490 static const unsigned char new_state[16] = {
1491 /* current state: new state: action: */
1492 /* (Invalid) */ TCP_CLOSE,
1493 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1494 /* TCP_SYN_SENT */ TCP_CLOSE,
1495 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1496 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1497 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1498 /* TCP_TIME_WAIT */ TCP_CLOSE,
1499 /* TCP_CLOSE */ TCP_CLOSE,
1500 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1501 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1502 /* TCP_LISTEN */ TCP_CLOSE,
1503 /* TCP_CLOSING */ TCP_CLOSING,
1504 };
1505
1506 static int tcp_close_state(struct sock *sk)
1507 {
1508 int next = (int)new_state[sk->sk_state];
1509 int ns = next & TCP_STATE_MASK;
1510
1511 tcp_set_state(sk, ns);
1512
1513 return next & TCP_ACTION_FIN;
1514 }
1515
1516 /*
1517 * Shutdown the sending side of a connection. Much like close except
1518 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1519 */
1520
1521 void tcp_shutdown(struct sock *sk, int how)
1522 {
1523 /* We need to grab some memory, and put together a FIN,
1524 * and then put it into the queue to be sent.
1525 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1526 */
1527 if (!(how & SEND_SHUTDOWN))
1528 return;
1529
1530 /* If we've already sent a FIN, or it's a closed state, skip this. */
1531 if ((1 << sk->sk_state) &
1532 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1533 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1534 /* Clear out any half completed packets. FIN if needed. */
1535 if (tcp_close_state(sk))
1536 tcp_send_fin(sk);
1537 }
1538 }
1539
1540 void tcp_close(struct sock *sk, long timeout)
1541 {
1542 struct sk_buff *skb;
1543 int data_was_unread = 0;
1544 int state;
1545
1546 lock_sock(sk);
1547 sk->sk_shutdown = SHUTDOWN_MASK;
1548
1549 if (sk->sk_state == TCP_LISTEN) {
1550 tcp_set_state(sk, TCP_CLOSE);
1551
1552 /* Special case. */
1553 inet_csk_listen_stop(sk);
1554
1555 goto adjudge_to_death;
1556 }
1557
1558 /* We need to flush the recv. buffs. We do this only on the
1559 * descriptor close, not protocol-sourced closes, because the
1560 * reader process may not have drained the data yet!
1561 */
1562 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1563 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1564 skb->h.th->fin;
1565 data_was_unread += len;
1566 __kfree_skb(skb);
1567 }
1568
1569 sk_stream_mem_reclaim(sk);
1570
1571 /* As outlined in draft-ietf-tcpimpl-prob-03.txt, section
1572 * 3.10, we send a RST here because data was lost. To
1573 * witness the awful effects of the old behavior of always
1574 * doing a FIN, run an older 2.1.x kernel or 2.0.x, start
1575 * a bulk GET in an FTP client, suspend the process, wait
1576 * for the client to advertise a zero window, then kill -9
1577 * the FTP client, wheee... Note: timeout is always zero
1578 * in such a case.
1579 */
1580 if (data_was_unread) {
1581 /* Unread data was tossed, zap the connection. */
1582 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1583 tcp_set_state(sk, TCP_CLOSE);
1584 tcp_send_active_reset(sk, GFP_KERNEL);
1585 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1586 /* Check zero linger _after_ checking for unread data. */
1587 sk->sk_prot->disconnect(sk, 0);
1588 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1589 } else if (tcp_close_state(sk)) {
1590 /* We FIN if the application ate all the data before
1591 * zapping the connection.
1592 */
1593
1594 /* RED-PEN. Formally speaking, we have broken TCP state
1595 * machine. State transitions:
1596 *
1597 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1598 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1599 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1600 *
1601 * are legal only when FIN has been sent (i.e. in window),
1602 * rather than queued out of window. Purists blame.
1603 *
1604 * F.e. "RFC state" is ESTABLISHED,
1605 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1606 *
1607 * The visible declinations are that sometimes
1608 * we enter time-wait state, when it is not required really
1609 * (harmless), do not send active resets, when they are
1610 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1611 * they look as CLOSING or LAST_ACK for Linux)
1612 * Probably, I missed some more holelets.
1613 * --ANK
1614 */
1615 tcp_send_fin(sk);
1616 }
1617
1618 sk_stream_wait_close(sk, timeout);
1619
1620 adjudge_to_death:
1621 state = sk->sk_state;
1622 sock_hold(sk);
1623 sock_orphan(sk);
1624 atomic_inc(sk->sk_prot->orphan_count);
1625
1626 /* It is the last release_sock in its life. It will remove backlog. */
1627 release_sock(sk);
1628
1629
1630 /* Now socket is owned by kernel and we acquire BH lock
1631 to finish close. No need to check for user refs.
1632 */
1633 local_bh_disable();
1634 bh_lock_sock(sk);
1635 BUG_TRAP(!sock_owned_by_user(sk));
1636
1637 /* Have we already been destroyed by a softirq or backlog? */
1638 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1639 goto out;
1640
1641 /* This is a (useful) BSD violating of the RFC. There is a
1642 * problem with TCP as specified in that the other end could
1643 * keep a socket open forever with no application left this end.
1644 * We use a 3 minute timeout (about the same as BSD) then kill
1645 * our end. If they send after that then tough - BUT: long enough
1646 * that we won't make the old 4*rto = almost no time - whoops
1647 * reset mistake.
1648 *
1649 * Nope, it was not mistake. It is really desired behaviour
1650 * f.e. on http servers, when such sockets are useless, but
1651 * consume significant resources. Let's do it with special
1652 * linger2 option. --ANK
1653 */
1654
1655 if (sk->sk_state == TCP_FIN_WAIT2) {
1656 struct tcp_sock *tp = tcp_sk(sk);
1657 if (tp->linger2 < 0) {
1658 tcp_set_state(sk, TCP_CLOSE);
1659 tcp_send_active_reset(sk, GFP_ATOMIC);
1660 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1661 } else {
1662 const int tmo = tcp_fin_time(sk);
1663
1664 if (tmo > TCP_TIMEWAIT_LEN) {
1665 inet_csk_reset_keepalive_timer(sk,
1666 tmo - TCP_TIMEWAIT_LEN);
1667 } else {
1668 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1669 goto out;
1670 }
1671 }
1672 }
1673 if (sk->sk_state != TCP_CLOSE) {
1674 sk_stream_mem_reclaim(sk);
1675 if (atomic_read(sk->sk_prot->orphan_count) > sysctl_tcp_max_orphans ||
1676 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
1677 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) {
1678 if (net_ratelimit())
1679 printk(KERN_INFO "TCP: too many of orphaned "
1680 "sockets\n");
1681 tcp_set_state(sk, TCP_CLOSE);
1682 tcp_send_active_reset(sk, GFP_ATOMIC);
1683 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1684 }
1685 }
1686
1687 if (sk->sk_state == TCP_CLOSE)
1688 inet_csk_destroy_sock(sk);
1689 /* Otherwise, socket is reprieved until protocol close. */
1690
1691 out:
1692 bh_unlock_sock(sk);
1693 local_bh_enable();
1694 sock_put(sk);
1695 }
1696
1697 /* These states need RST on ABORT according to RFC793 */
1698
1699 static inline int tcp_need_reset(int state)
1700 {
1701 return (1 << state) &
1702 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1703 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1704 }
1705
1706 int tcp_disconnect(struct sock *sk, int flags)
1707 {
1708 struct inet_sock *inet = inet_sk(sk);
1709 struct inet_connection_sock *icsk = inet_csk(sk);
1710 struct tcp_sock *tp = tcp_sk(sk);
1711 int err = 0;
1712 int old_state = sk->sk_state;
1713
1714 if (old_state != TCP_CLOSE)
1715 tcp_set_state(sk, TCP_CLOSE);
1716
1717 /* ABORT function of RFC793 */
1718 if (old_state == TCP_LISTEN) {
1719 inet_csk_listen_stop(sk);
1720 } else if (tcp_need_reset(old_state) ||
1721 (tp->snd_nxt != tp->write_seq &&
1722 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1723 /* The last check adjusts for discrepancy of Linux wrt. RFC
1724 * states
1725 */
1726 tcp_send_active_reset(sk, gfp_any());
1727 sk->sk_err = ECONNRESET;
1728 } else if (old_state == TCP_SYN_SENT)
1729 sk->sk_err = ECONNRESET;
1730
1731 tcp_clear_xmit_timers(sk);
1732 __skb_queue_purge(&sk->sk_receive_queue);
1733 sk_stream_writequeue_purge(sk);
1734 __skb_queue_purge(&tp->out_of_order_queue);
1735 #ifdef CONFIG_NET_DMA
1736 __skb_queue_purge(&sk->sk_async_wait_queue);
1737 #endif
1738
1739 inet->dport = 0;
1740
1741 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1742 inet_reset_saddr(sk);
1743
1744 sk->sk_shutdown = 0;
1745 sock_reset_flag(sk, SOCK_DONE);
1746 tp->srtt = 0;
1747 if ((tp->write_seq += tp->max_window + 2) == 0)
1748 tp->write_seq = 1;
1749 icsk->icsk_backoff = 0;
1750 tp->snd_cwnd = 2;
1751 icsk->icsk_probes_out = 0;
1752 tp->packets_out = 0;
1753 tp->snd_ssthresh = 0x7fffffff;
1754 tp->snd_cwnd_cnt = 0;
1755 tp->bytes_acked = 0;
1756 tcp_set_ca_state(sk, TCP_CA_Open);
1757 tcp_clear_retrans(tp);
1758 inet_csk_delack_init(sk);
1759 sk->sk_send_head = NULL;
1760 tp->rx_opt.saw_tstamp = 0;
1761 tcp_sack_reset(&tp->rx_opt);
1762 __sk_dst_reset(sk);
1763
1764 BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1765
1766 sk->sk_error_report(sk);
1767 return err;
1768 }
1769
1770 /*
1771 * Socket option code for TCP.
1772 */
1773 static int do_tcp_setsockopt(struct sock *sk, int level,
1774 int optname, char __user *optval, int optlen)
1775 {
1776 struct tcp_sock *tp = tcp_sk(sk);
1777 struct inet_connection_sock *icsk = inet_csk(sk);
1778 int val;
1779 int err = 0;
1780
1781 /* This is a string value all the others are int's */
1782 if (optname == TCP_CONGESTION) {
1783 char name[TCP_CA_NAME_MAX];
1784
1785 if (optlen < 1)
1786 return -EINVAL;
1787
1788 val = strncpy_from_user(name, optval,
1789 min(TCP_CA_NAME_MAX-1, optlen));
1790 if (val < 0)
1791 return -EFAULT;
1792 name[val] = 0;
1793
1794 lock_sock(sk);
1795 err = tcp_set_congestion_control(sk, name);
1796 release_sock(sk);
1797 return err;
1798 }
1799
1800 if (optlen < sizeof(int))
1801 return -EINVAL;
1802
1803 if (get_user(val, (int __user *)optval))
1804 return -EFAULT;
1805
1806 lock_sock(sk);
1807
1808 switch (optname) {
1809 case TCP_MAXSEG:
1810 /* Values greater than interface MTU won't take effect. However
1811 * at the point when this call is done we typically don't yet
1812 * know which interface is going to be used */
1813 if (val < 8 || val > MAX_TCP_WINDOW) {
1814 err = -EINVAL;
1815 break;
1816 }
1817 tp->rx_opt.user_mss = val;
1818 break;
1819
1820 case TCP_NODELAY:
1821 if (val) {
1822 /* TCP_NODELAY is weaker than TCP_CORK, so that
1823 * this option on corked socket is remembered, but
1824 * it is not activated until cork is cleared.
1825 *
1826 * However, when TCP_NODELAY is set we make
1827 * an explicit push, which overrides even TCP_CORK
1828 * for currently queued segments.
1829 */
1830 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
1831 tcp_push_pending_frames(sk, tp);
1832 } else {
1833 tp->nonagle &= ~TCP_NAGLE_OFF;
1834 }
1835 break;
1836
1837 case TCP_CORK:
1838 /* When set indicates to always queue non-full frames.
1839 * Later the user clears this option and we transmit
1840 * any pending partial frames in the queue. This is
1841 * meant to be used alongside sendfile() to get properly
1842 * filled frames when the user (for example) must write
1843 * out headers with a write() call first and then use
1844 * sendfile to send out the data parts.
1845 *
1846 * TCP_CORK can be set together with TCP_NODELAY and it is
1847 * stronger than TCP_NODELAY.
1848 */
1849 if (val) {
1850 tp->nonagle |= TCP_NAGLE_CORK;
1851 } else {
1852 tp->nonagle &= ~TCP_NAGLE_CORK;
1853 if (tp->nonagle&TCP_NAGLE_OFF)
1854 tp->nonagle |= TCP_NAGLE_PUSH;
1855 tcp_push_pending_frames(sk, tp);
1856 }
1857 break;
1858
1859 case TCP_KEEPIDLE:
1860 if (val < 1 || val > MAX_TCP_KEEPIDLE)
1861 err = -EINVAL;
1862 else {
1863 tp->keepalive_time = val * HZ;
1864 if (sock_flag(sk, SOCK_KEEPOPEN) &&
1865 !((1 << sk->sk_state) &
1866 (TCPF_CLOSE | TCPF_LISTEN))) {
1867 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
1868 if (tp->keepalive_time > elapsed)
1869 elapsed = tp->keepalive_time - elapsed;
1870 else
1871 elapsed = 0;
1872 inet_csk_reset_keepalive_timer(sk, elapsed);
1873 }
1874 }
1875 break;
1876 case TCP_KEEPINTVL:
1877 if (val < 1 || val > MAX_TCP_KEEPINTVL)
1878 err = -EINVAL;
1879 else
1880 tp->keepalive_intvl = val * HZ;
1881 break;
1882 case TCP_KEEPCNT:
1883 if (val < 1 || val > MAX_TCP_KEEPCNT)
1884 err = -EINVAL;
1885 else
1886 tp->keepalive_probes = val;
1887 break;
1888 case TCP_SYNCNT:
1889 if (val < 1 || val > MAX_TCP_SYNCNT)
1890 err = -EINVAL;
1891 else
1892 icsk->icsk_syn_retries = val;
1893 break;
1894
1895 case TCP_LINGER2:
1896 if (val < 0)
1897 tp->linger2 = -1;
1898 else if (val > sysctl_tcp_fin_timeout / HZ)
1899 tp->linger2 = 0;
1900 else
1901 tp->linger2 = val * HZ;
1902 break;
1903
1904 case TCP_DEFER_ACCEPT:
1905 icsk->icsk_accept_queue.rskq_defer_accept = 0;
1906 if (val > 0) {
1907 /* Translate value in seconds to number of
1908 * retransmits */
1909 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
1910 val > ((TCP_TIMEOUT_INIT / HZ) <<
1911 icsk->icsk_accept_queue.rskq_defer_accept))
1912 icsk->icsk_accept_queue.rskq_defer_accept++;
1913 icsk->icsk_accept_queue.rskq_defer_accept++;
1914 }
1915 break;
1916
1917 case TCP_WINDOW_CLAMP:
1918 if (!val) {
1919 if (sk->sk_state != TCP_CLOSE) {
1920 err = -EINVAL;
1921 break;
1922 }
1923 tp->window_clamp = 0;
1924 } else
1925 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
1926 SOCK_MIN_RCVBUF / 2 : val;
1927 break;
1928
1929 case TCP_QUICKACK:
1930 if (!val) {
1931 icsk->icsk_ack.pingpong = 1;
1932 } else {
1933 icsk->icsk_ack.pingpong = 0;
1934 if ((1 << sk->sk_state) &
1935 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
1936 inet_csk_ack_scheduled(sk)) {
1937 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
1938 tcp_cleanup_rbuf(sk, 1);
1939 if (!(val & 1))
1940 icsk->icsk_ack.pingpong = 1;
1941 }
1942 }
1943 break;
1944
1945 default:
1946 err = -ENOPROTOOPT;
1947 break;
1948 };
1949 release_sock(sk);
1950 return err;
1951 }
1952
1953 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
1954 int optlen)
1955 {
1956 struct inet_connection_sock *icsk = inet_csk(sk);
1957
1958 if (level != SOL_TCP)
1959 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1960 optval, optlen);
1961 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1962 }
1963
1964 #ifdef CONFIG_COMPAT
1965 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
1966 char __user *optval, int optlen)
1967 {
1968 if (level != SOL_TCP)
1969 return inet_csk_compat_setsockopt(sk, level, optname,
1970 optval, optlen);
1971 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1972 }
1973
1974 EXPORT_SYMBOL(compat_tcp_setsockopt);
1975 #endif
1976
1977 /* Return information about state of tcp endpoint in API format. */
1978 void tcp_get_info(struct sock *sk, struct tcp_info *info)
1979 {
1980 struct tcp_sock *tp = tcp_sk(sk);
1981 const struct inet_connection_sock *icsk = inet_csk(sk);
1982 u32 now = tcp_time_stamp;
1983
1984 memset(info, 0, sizeof(*info));
1985
1986 info->tcpi_state = sk->sk_state;
1987 info->tcpi_ca_state = icsk->icsk_ca_state;
1988 info->tcpi_retransmits = icsk->icsk_retransmits;
1989 info->tcpi_probes = icsk->icsk_probes_out;
1990 info->tcpi_backoff = icsk->icsk_backoff;
1991
1992 if (tp->rx_opt.tstamp_ok)
1993 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1994 if (tp->rx_opt.sack_ok)
1995 info->tcpi_options |= TCPI_OPT_SACK;
1996 if (tp->rx_opt.wscale_ok) {
1997 info->tcpi_options |= TCPI_OPT_WSCALE;
1998 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
1999 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2000 }
2001
2002 if (tp->ecn_flags&TCP_ECN_OK)
2003 info->tcpi_options |= TCPI_OPT_ECN;
2004
2005 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2006 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2007 info->tcpi_snd_mss = tp->mss_cache;
2008 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2009
2010 info->tcpi_unacked = tp->packets_out;
2011 info->tcpi_sacked = tp->sacked_out;
2012 info->tcpi_lost = tp->lost_out;
2013 info->tcpi_retrans = tp->retrans_out;
2014 info->tcpi_fackets = tp->fackets_out;
2015
2016 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2017 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2018 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2019
2020 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2021 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2022 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2023 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2024 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2025 info->tcpi_snd_cwnd = tp->snd_cwnd;
2026 info->tcpi_advmss = tp->advmss;
2027 info->tcpi_reordering = tp->reordering;
2028
2029 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2030 info->tcpi_rcv_space = tp->rcvq_space.space;
2031
2032 info->tcpi_total_retrans = tp->total_retrans;
2033 }
2034
2035 EXPORT_SYMBOL_GPL(tcp_get_info);
2036
2037 static int do_tcp_getsockopt(struct sock *sk, int level,
2038 int optname, char __user *optval, int __user *optlen)
2039 {
2040 struct inet_connection_sock *icsk = inet_csk(sk);
2041 struct tcp_sock *tp = tcp_sk(sk);
2042 int val, len;
2043
2044 if (get_user(len, optlen))
2045 return -EFAULT;
2046
2047 len = min_t(unsigned int, len, sizeof(int));
2048
2049 if (len < 0)
2050 return -EINVAL;
2051
2052 switch (optname) {
2053 case TCP_MAXSEG:
2054 val = tp->mss_cache;
2055 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2056 val = tp->rx_opt.user_mss;
2057 break;
2058 case TCP_NODELAY:
2059 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2060 break;
2061 case TCP_CORK:
2062 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2063 break;
2064 case TCP_KEEPIDLE:
2065 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2066 break;
2067 case TCP_KEEPINTVL:
2068 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2069 break;
2070 case TCP_KEEPCNT:
2071 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2072 break;
2073 case TCP_SYNCNT:
2074 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2075 break;
2076 case TCP_LINGER2:
2077 val = tp->linger2;
2078 if (val >= 0)
2079 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2080 break;
2081 case TCP_DEFER_ACCEPT:
2082 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2083 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2084 break;
2085 case TCP_WINDOW_CLAMP:
2086 val = tp->window_clamp;
2087 break;
2088 case TCP_INFO: {
2089 struct tcp_info info;
2090
2091 if (get_user(len, optlen))
2092 return -EFAULT;
2093
2094 tcp_get_info(sk, &info);
2095
2096 len = min_t(unsigned int, len, sizeof(info));
2097 if (put_user(len, optlen))
2098 return -EFAULT;
2099 if (copy_to_user(optval, &info, len))
2100 return -EFAULT;
2101 return 0;
2102 }
2103 case TCP_QUICKACK:
2104 val = !icsk->icsk_ack.pingpong;
2105 break;
2106
2107 case TCP_CONGESTION:
2108 if (get_user(len, optlen))
2109 return -EFAULT;
2110 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2111 if (put_user(len, optlen))
2112 return -EFAULT;
2113 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2114 return -EFAULT;
2115 return 0;
2116 default:
2117 return -ENOPROTOOPT;
2118 };
2119
2120 if (put_user(len, optlen))
2121 return -EFAULT;
2122 if (copy_to_user(optval, &val, len))
2123 return -EFAULT;
2124 return 0;
2125 }
2126
2127 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2128 int __user *optlen)
2129 {
2130 struct inet_connection_sock *icsk = inet_csk(sk);
2131
2132 if (level != SOL_TCP)
2133 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2134 optval, optlen);
2135 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2136 }
2137
2138 #ifdef CONFIG_COMPAT
2139 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2140 char __user *optval, int __user *optlen)
2141 {
2142 if (level != SOL_TCP)
2143 return inet_csk_compat_getsockopt(sk, level, optname,
2144 optval, optlen);
2145 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2146 }
2147
2148 EXPORT_SYMBOL(compat_tcp_getsockopt);
2149 #endif
2150
2151 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2152 {
2153 struct sk_buff *segs = ERR_PTR(-EINVAL);
2154 struct tcphdr *th;
2155 unsigned thlen;
2156 unsigned int seq;
2157 unsigned int delta;
2158 unsigned int oldlen;
2159 unsigned int len;
2160
2161 if (!pskb_may_pull(skb, sizeof(*th)))
2162 goto out;
2163
2164 th = skb->h.th;
2165 thlen = th->doff * 4;
2166 if (thlen < sizeof(*th))
2167 goto out;
2168
2169 if (!pskb_may_pull(skb, thlen))
2170 goto out;
2171
2172 oldlen = (u16)~skb->len;
2173 __skb_pull(skb, thlen);
2174
2175 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2176 /* Packet is from an untrusted source, reset gso_segs. */
2177 int type = skb_shinfo(skb)->gso_type;
2178 int mss;
2179
2180 if (unlikely(type &
2181 ~(SKB_GSO_TCPV4 |
2182 SKB_GSO_DODGY |
2183 SKB_GSO_TCP_ECN |
2184 SKB_GSO_TCPV6 |
2185 0) ||
2186 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2187 goto out;
2188
2189 mss = skb_shinfo(skb)->gso_size;
2190 skb_shinfo(skb)->gso_segs = (skb->len + mss - 1) / mss;
2191
2192 segs = NULL;
2193 goto out;
2194 }
2195
2196 segs = skb_segment(skb, features);
2197 if (IS_ERR(segs))
2198 goto out;
2199
2200 len = skb_shinfo(skb)->gso_size;
2201 delta = htonl(oldlen + (thlen + len));
2202
2203 skb = segs;
2204 th = skb->h.th;
2205 seq = ntohl(th->seq);
2206
2207 do {
2208 th->fin = th->psh = 0;
2209
2210 th->check = ~csum_fold(th->check + delta);
2211 if (skb->ip_summed != CHECKSUM_PARTIAL)
2212 th->check = csum_fold(csum_partial(skb->h.raw, thlen,
2213 skb->csum));
2214
2215 seq += len;
2216 skb = skb->next;
2217 th = skb->h.th;
2218
2219 th->seq = htonl(seq);
2220 th->cwr = 0;
2221 } while (skb->next);
2222
2223 delta = htonl(oldlen + (skb->tail - skb->h.raw) + skb->data_len);
2224 th->check = ~csum_fold(th->check + delta);
2225 if (skb->ip_summed != CHECKSUM_PARTIAL)
2226 th->check = csum_fold(csum_partial(skb->h.raw, thlen,
2227 skb->csum));
2228
2229 out:
2230 return segs;
2231 }
2232 EXPORT_SYMBOL(tcp_tso_segment);
2233
2234 extern void __skb_cb_too_small_for_tcp(int, int);
2235 extern struct tcp_congestion_ops tcp_reno;
2236
2237 static __initdata unsigned long thash_entries;
2238 static int __init set_thash_entries(char *str)
2239 {
2240 if (!str)
2241 return 0;
2242 thash_entries = simple_strtoul(str, &str, 0);
2243 return 1;
2244 }
2245 __setup("thash_entries=", set_thash_entries);
2246
2247 void __init tcp_init(void)
2248 {
2249 struct sk_buff *skb = NULL;
2250 unsigned long limit;
2251 int order, i, max_share;
2252
2253 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2254 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2255 sizeof(skb->cb));
2256
2257 tcp_hashinfo.bind_bucket_cachep =
2258 kmem_cache_create("tcp_bind_bucket",
2259 sizeof(struct inet_bind_bucket), 0,
2260 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
2261
2262 /* Size and allocate the main established and bind bucket
2263 * hash tables.
2264 *
2265 * The methodology is similar to that of the buffer cache.
2266 */
2267 tcp_hashinfo.ehash =
2268 alloc_large_system_hash("TCP established",
2269 sizeof(struct inet_ehash_bucket),
2270 thash_entries,
2271 (num_physpages >= 128 * 1024) ?
2272 13 : 15,
2273 HASH_HIGHMEM,
2274 &tcp_hashinfo.ehash_size,
2275 NULL,
2276 0);
2277 tcp_hashinfo.ehash_size = (1 << tcp_hashinfo.ehash_size) >> 1;
2278 for (i = 0; i < (tcp_hashinfo.ehash_size << 1); i++) {
2279 rwlock_init(&tcp_hashinfo.ehash[i].lock);
2280 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2281 }
2282
2283 tcp_hashinfo.bhash =
2284 alloc_large_system_hash("TCP bind",
2285 sizeof(struct inet_bind_hashbucket),
2286 tcp_hashinfo.ehash_size,
2287 (num_physpages >= 128 * 1024) ?
2288 13 : 15,
2289 HASH_HIGHMEM,
2290 &tcp_hashinfo.bhash_size,
2291 NULL,
2292 64 * 1024);
2293 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2294 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2295 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2296 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2297 }
2298
2299 /* Try to be a bit smarter and adjust defaults depending
2300 * on available memory.
2301 */
2302 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2303 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2304 order++)
2305 ;
2306 if (order >= 4) {
2307 sysctl_local_port_range[0] = 32768;
2308 sysctl_local_port_range[1] = 61000;
2309 tcp_death_row.sysctl_max_tw_buckets = 180000;
2310 sysctl_tcp_max_orphans = 4096 << (order - 4);
2311 sysctl_max_syn_backlog = 1024;
2312 } else if (order < 3) {
2313 sysctl_local_port_range[0] = 1024 * (3 - order);
2314 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2315 sysctl_tcp_max_orphans >>= (3 - order);
2316 sysctl_max_syn_backlog = 128;
2317 }
2318
2319 sysctl_tcp_mem[0] = 768 << order;
2320 sysctl_tcp_mem[1] = 1024 << order;
2321 sysctl_tcp_mem[2] = 1536 << order;
2322
2323 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2324 max_share = min(4UL*1024*1024, limit);
2325
2326 sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM;
2327 sysctl_tcp_wmem[1] = 16*1024;
2328 sysctl_tcp_wmem[2] = max(64*1024, max_share);
2329
2330 sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM;
2331 sysctl_tcp_rmem[1] = 87380;
2332 sysctl_tcp_rmem[2] = max(87380, max_share);
2333
2334 printk(KERN_INFO "TCP: Hash tables configured "
2335 "(established %d bind %d)\n",
2336 tcp_hashinfo.ehash_size << 1, tcp_hashinfo.bhash_size);
2337
2338 tcp_register_congestion_control(&tcp_reno);
2339 }
2340
2341 EXPORT_SYMBOL(tcp_close);
2342 EXPORT_SYMBOL(tcp_disconnect);
2343 EXPORT_SYMBOL(tcp_getsockopt);
2344 EXPORT_SYMBOL(tcp_ioctl);
2345 EXPORT_SYMBOL(tcp_poll);
2346 EXPORT_SYMBOL(tcp_read_sock);
2347 EXPORT_SYMBOL(tcp_recvmsg);
2348 EXPORT_SYMBOL(tcp_sendmsg);
2349 EXPORT_SYMBOL(tcp_sendpage);
2350 EXPORT_SYMBOL(tcp_setsockopt);
2351 EXPORT_SYMBOL(tcp_shutdown);
2352 EXPORT_SYMBOL(tcp_statistics);
Linux 2.6 libata-dev (mirror)