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[PATCH] libertas: Purge non-mesh ioctls
[linux-2.6/libata-dev.git] / net / ipv4 / tcp.c
blobbd4c295f5d796347c2ba705710c417a50d6002fe
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/fs.h>
256 #include <linux/random.h>
257 #include <linux/bootmem.h>
258 #include <linux/cache.h>
259 #include <linux/err.h>
260 #include <linux/crypto.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 __read_mostly;
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 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->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 sk_buff *skb)
463 {
464 struct tcp_sock *tp = tcp_sk(sk);
465 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
466
467 skb->csum = 0;
468 tcb->seq = tcb->end_seq = tp->write_seq;
469 tcb->flags = TCPCB_FLAG_ACK;
470 tcb->sacked = 0;
471 skb_header_release(skb);
472 tcp_add_write_queue_tail(sk, skb);
473 sk_charge_skb(sk, skb);
474 if (tp->nonagle & TCP_NAGLE_PUSH)
475 tp->nonagle &= ~TCP_NAGLE_PUSH;
476 }
477
478 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
479 struct sk_buff *skb)
480 {
481 if (flags & MSG_OOB) {
482 tp->urg_mode = 1;
483 tp->snd_up = tp->write_seq;
484 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
485 }
486 }
487
488 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
489 int nonagle)
490 {
491 struct tcp_sock *tp = tcp_sk(sk);
492
493 if (tcp_send_head(sk)) {
494 struct sk_buff *skb = tcp_write_queue_tail(sk);
495 if (!(flags & MSG_MORE) || forced_push(tp))
496 tcp_mark_push(tp, skb);
497 tcp_mark_urg(tp, flags, skb);
498 __tcp_push_pending_frames(sk, mss_now,
499 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
500 }
501 }
502
503 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
504 size_t psize, int flags)
505 {
506 struct tcp_sock *tp = tcp_sk(sk);
507 int mss_now, size_goal;
508 int err;
509 ssize_t copied;
510 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
511
512 /* Wait for a connection to finish. */
513 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
514 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
515 goto out_err;
516
517 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
518
519 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
520 size_goal = tp->xmit_size_goal;
521 copied = 0;
522
523 err = -EPIPE;
524 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
525 goto do_error;
526
527 while (psize > 0) {
528 struct sk_buff *skb = tcp_write_queue_tail(sk);
529 struct page *page = pages[poffset / PAGE_SIZE];
530 int copy, i, can_coalesce;
531 int offset = poffset % PAGE_SIZE;
532 int size = min_t(size_t, psize, PAGE_SIZE - offset);
533
534 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
535 new_segment:
536 if (!sk_stream_memory_free(sk))
537 goto wait_for_sndbuf;
538
539 skb = sk_stream_alloc_pskb(sk, 0, 0,
540 sk->sk_allocation);
541 if (!skb)
542 goto wait_for_memory;
543
544 skb_entail(sk, skb);
545 copy = size_goal;
546 }
547
548 if (copy > size)
549 copy = size;
550
551 i = skb_shinfo(skb)->nr_frags;
552 can_coalesce = skb_can_coalesce(skb, i, page, offset);
553 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
554 tcp_mark_push(tp, skb);
555 goto new_segment;
556 }
557 if (!sk_stream_wmem_schedule(sk, copy))
558 goto wait_for_memory;
559
560 if (can_coalesce) {
561 skb_shinfo(skb)->frags[i - 1].size += copy;
562 } else {
563 get_page(page);
564 skb_fill_page_desc(skb, i, page, offset, copy);
565 }
566
567 skb->len += copy;
568 skb->data_len += copy;
569 skb->truesize += copy;
570 sk->sk_wmem_queued += copy;
571 sk->sk_forward_alloc -= copy;
572 skb->ip_summed = CHECKSUM_PARTIAL;
573 tp->write_seq += copy;
574 TCP_SKB_CB(skb)->end_seq += copy;
575 skb_shinfo(skb)->gso_segs = 0;
576
577 if (!copied)
578 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
579
580 copied += copy;
581 poffset += copy;
582 if (!(psize -= copy))
583 goto out;
584
585 if (skb->len < mss_now || (flags & MSG_OOB))
586 continue;
587
588 if (forced_push(tp)) {
589 tcp_mark_push(tp, skb);
590 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
591 } else if (skb == tcp_send_head(sk))
592 tcp_push_one(sk, mss_now);
593 continue;
594
595 wait_for_sndbuf:
596 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
597 wait_for_memory:
598 if (copied)
599 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
600
601 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
602 goto do_error;
603
604 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
605 size_goal = tp->xmit_size_goal;
606 }
607
608 out:
609 if (copied)
610 tcp_push(sk, flags, mss_now, tp->nonagle);
611 return copied;
612
613 do_error:
614 if (copied)
615 goto out;
616 out_err:
617 return sk_stream_error(sk, flags, err);
618 }
619
620 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
621 size_t size, int flags)
622 {
623 ssize_t res;
624 struct sock *sk = sock->sk;
625
626 if (!(sk->sk_route_caps & NETIF_F_SG) ||
627 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
628 return sock_no_sendpage(sock, page, offset, size, flags);
629
630 lock_sock(sk);
631 TCP_CHECK_TIMER(sk);
632 res = do_tcp_sendpages(sk, &page, offset, size, flags);
633 TCP_CHECK_TIMER(sk);
634 release_sock(sk);
635 return res;
636 }
637
638 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
639 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
640
641 static inline int select_size(struct sock *sk)
642 {
643 struct tcp_sock *tp = tcp_sk(sk);
644 int tmp = tp->mss_cache;
645
646 if (sk->sk_route_caps & NETIF_F_SG) {
647 if (sk_can_gso(sk))
648 tmp = 0;
649 else {
650 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
651
652 if (tmp >= pgbreak &&
653 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
654 tmp = pgbreak;
655 }
656 }
657
658 return tmp;
659 }
660
661 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
662 size_t size)
663 {
664 struct iovec *iov;
665 struct tcp_sock *tp = tcp_sk(sk);
666 struct sk_buff *skb;
667 int iovlen, flags;
668 int mss_now, size_goal;
669 int err, copied;
670 long timeo;
671
672 lock_sock(sk);
673 TCP_CHECK_TIMER(sk);
674
675 flags = msg->msg_flags;
676 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
677
678 /* Wait for a connection to finish. */
679 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
680 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
681 goto out_err;
682
683 /* This should be in poll */
684 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
685
686 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
687 size_goal = tp->xmit_size_goal;
688
689 /* Ok commence sending. */
690 iovlen = msg->msg_iovlen;
691 iov = msg->msg_iov;
692 copied = 0;
693
694 err = -EPIPE;
695 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
696 goto do_error;
697
698 while (--iovlen >= 0) {
699 int seglen = iov->iov_len;
700 unsigned char __user *from = iov->iov_base;
701
702 iov++;
703
704 while (seglen > 0) {
705 int copy;
706
707 skb = tcp_write_queue_tail(sk);
708
709 if (!tcp_send_head(sk) ||
710 (copy = size_goal - skb->len) <= 0) {
711
712 new_segment:
713 /* Allocate new segment. If the interface is SG,
714 * allocate skb fitting to single page.
715 */
716 if (!sk_stream_memory_free(sk))
717 goto wait_for_sndbuf;
718
719 skb = sk_stream_alloc_pskb(sk, select_size(sk),
720 0, sk->sk_allocation);
721 if (!skb)
722 goto wait_for_memory;
723
724 /*
725 * Check whether we can use HW checksum.
726 */
727 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
728 skb->ip_summed = CHECKSUM_PARTIAL;
729
730 skb_entail(sk, skb);
731 copy = size_goal;
732 }
733
734 /* Try to append data to the end of skb. */
735 if (copy > seglen)
736 copy = seglen;
737
738 /* Where to copy to? */
739 if (skb_tailroom(skb) > 0) {
740 /* We have some space in skb head. Superb! */
741 if (copy > skb_tailroom(skb))
742 copy = skb_tailroom(skb);
743 if ((err = skb_add_data(skb, from, copy)) != 0)
744 goto do_fault;
745 } else {
746 int merge = 0;
747 int i = skb_shinfo(skb)->nr_frags;
748 struct page *page = TCP_PAGE(sk);
749 int off = TCP_OFF(sk);
750
751 if (skb_can_coalesce(skb, i, page, off) &&
752 off != PAGE_SIZE) {
753 /* We can extend the last page
754 * fragment. */
755 merge = 1;
756 } else if (i == MAX_SKB_FRAGS ||
757 (!i &&
758 !(sk->sk_route_caps & NETIF_F_SG))) {
759 /* Need to add new fragment and cannot
760 * do this because interface is non-SG,
761 * or because all the page slots are
762 * busy. */
763 tcp_mark_push(tp, skb);
764 goto new_segment;
765 } else if (page) {
766 if (off == PAGE_SIZE) {
767 put_page(page);
768 TCP_PAGE(sk) = page = NULL;
769 off = 0;
770 }
771 } else
772 off = 0;
773
774 if (copy > PAGE_SIZE - off)
775 copy = PAGE_SIZE - off;
776
777 if (!sk_stream_wmem_schedule(sk, copy))
778 goto wait_for_memory;
779
780 if (!page) {
781 /* Allocate new cache page. */
782 if (!(page = sk_stream_alloc_page(sk)))
783 goto wait_for_memory;
784 }
785
786 /* Time to copy data. We are close to
787 * the end! */
788 err = skb_copy_to_page(sk, from, skb, page,
789 off, copy);
790 if (err) {
791 /* If this page was new, give it to the
792 * socket so it does not get leaked.
793 */
794 if (!TCP_PAGE(sk)) {
795 TCP_PAGE(sk) = page;
796 TCP_OFF(sk) = 0;
797 }
798 goto do_error;
799 }
800
801 /* Update the skb. */
802 if (merge) {
803 skb_shinfo(skb)->frags[i - 1].size +=
804 copy;
805 } else {
806 skb_fill_page_desc(skb, i, page, off, copy);
807 if (TCP_PAGE(sk)) {
808 get_page(page);
809 } else if (off + copy < PAGE_SIZE) {
810 get_page(page);
811 TCP_PAGE(sk) = page;
812 }
813 }
814
815 TCP_OFF(sk) = off + copy;
816 }
817
818 if (!copied)
819 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
820
821 tp->write_seq += copy;
822 TCP_SKB_CB(skb)->end_seq += copy;
823 skb_shinfo(skb)->gso_segs = 0;
824
825 from += copy;
826 copied += copy;
827 if ((seglen -= copy) == 0 && iovlen == 0)
828 goto out;
829
830 if (skb->len < mss_now || (flags & MSG_OOB))
831 continue;
832
833 if (forced_push(tp)) {
834 tcp_mark_push(tp, skb);
835 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
836 } else if (skb == tcp_send_head(sk))
837 tcp_push_one(sk, mss_now);
838 continue;
839
840 wait_for_sndbuf:
841 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
842 wait_for_memory:
843 if (copied)
844 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
845
846 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
847 goto do_error;
848
849 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
850 size_goal = tp->xmit_size_goal;
851 }
852 }
853
854 out:
855 if (copied)
856 tcp_push(sk, flags, mss_now, tp->nonagle);
857 TCP_CHECK_TIMER(sk);
858 release_sock(sk);
859 return copied;
860
861 do_fault:
862 if (!skb->len) {
863 tcp_unlink_write_queue(skb, sk);
864 /* It is the one place in all of TCP, except connection
865 * reset, where we can be unlinking the send_head.
866 */
867 tcp_check_send_head(sk, skb);
868 sk_stream_free_skb(sk, skb);
869 }
870
871 do_error:
872 if (copied)
873 goto out;
874 out_err:
875 err = sk_stream_error(sk, flags, err);
876 TCP_CHECK_TIMER(sk);
877 release_sock(sk);
878 return err;
879 }
880
881 /*
882 * Handle reading urgent data. BSD has very simple semantics for
883 * this, no blocking and very strange errors 8)
884 */
885
886 static int tcp_recv_urg(struct sock *sk, long timeo,
887 struct msghdr *msg, int len, int flags,
888 int *addr_len)
889 {
890 struct tcp_sock *tp = tcp_sk(sk);
891
892 /* No URG data to read. */
893 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
894 tp->urg_data == TCP_URG_READ)
895 return -EINVAL; /* Yes this is right ! */
896
897 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
898 return -ENOTCONN;
899
900 if (tp->urg_data & TCP_URG_VALID) {
901 int err = 0;
902 char c = tp->urg_data;
903
904 if (!(flags & MSG_PEEK))
905 tp->urg_data = TCP_URG_READ;
906
907 /* Read urgent data. */
908 msg->msg_flags |= MSG_OOB;
909
910 if (len > 0) {
911 if (!(flags & MSG_TRUNC))
912 err = memcpy_toiovec(msg->msg_iov, &c, 1);
913 len = 1;
914 } else
915 msg->msg_flags |= MSG_TRUNC;
916
917 return err ? -EFAULT : len;
918 }
919
920 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
921 return 0;
922
923 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
924 * the available implementations agree in this case:
925 * this call should never block, independent of the
926 * blocking state of the socket.
927 * Mike <pall@rz.uni-karlsruhe.de>
928 */
929 return -EAGAIN;
930 }
931
932 /* Clean up the receive buffer for full frames taken by the user,
933 * then send an ACK if necessary. COPIED is the number of bytes
934 * tcp_recvmsg has given to the user so far, it speeds up the
935 * calculation of whether or not we must ACK for the sake of
936 * a window update.
937 */
938 void tcp_cleanup_rbuf(struct sock *sk, int copied)
939 {
940 struct tcp_sock *tp = tcp_sk(sk);
941 int time_to_ack = 0;
942
943 #if TCP_DEBUG
944 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
945
946 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
947 #endif
948
949 if (inet_csk_ack_scheduled(sk)) {
950 const struct inet_connection_sock *icsk = inet_csk(sk);
951 /* Delayed ACKs frequently hit locked sockets during bulk
952 * receive. */
953 if (icsk->icsk_ack.blocked ||
954 /* Once-per-two-segments ACK was not sent by tcp_input.c */
955 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
956 /*
957 * If this read emptied read buffer, we send ACK, if
958 * connection is not bidirectional, user drained
959 * receive buffer and there was a small segment
960 * in queue.
961 */
962 (copied > 0 &&
963 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
964 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
965 !icsk->icsk_ack.pingpong)) &&
966 !atomic_read(&sk->sk_rmem_alloc)))
967 time_to_ack = 1;
968 }
969
970 /* We send an ACK if we can now advertise a non-zero window
971 * which has been raised "significantly".
972 *
973 * Even if window raised up to infinity, do not send window open ACK
974 * in states, where we will not receive more. It is useless.
975 */
976 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
977 __u32 rcv_window_now = tcp_receive_window(tp);
978
979 /* Optimize, __tcp_select_window() is not cheap. */
980 if (2*rcv_window_now <= tp->window_clamp) {
981 __u32 new_window = __tcp_select_window(sk);
982
983 /* Send ACK now, if this read freed lots of space
984 * in our buffer. Certainly, new_window is new window.
985 * We can advertise it now, if it is not less than current one.
986 * "Lots" means "at least twice" here.
987 */
988 if (new_window && new_window >= 2 * rcv_window_now)
989 time_to_ack = 1;
990 }
991 }
992 if (time_to_ack)
993 tcp_send_ack(sk);
994 }
995
996 static void tcp_prequeue_process(struct sock *sk)
997 {
998 struct sk_buff *skb;
999 struct tcp_sock *tp = tcp_sk(sk);
1000
1001 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
1002
1003 /* RX process wants to run with disabled BHs, though it is not
1004 * necessary */
1005 local_bh_disable();
1006 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1007 sk->sk_backlog_rcv(sk, skb);
1008 local_bh_enable();
1009
1010 /* Clear memory counter. */
1011 tp->ucopy.memory = 0;
1012 }
1013
1014 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1015 {
1016 struct sk_buff *skb;
1017 u32 offset;
1018
1019 skb_queue_walk(&sk->sk_receive_queue, skb) {
1020 offset = seq - TCP_SKB_CB(skb)->seq;
1021 if (tcp_hdr(skb)->syn)
1022 offset--;
1023 if (offset < skb->len || tcp_hdr(skb)->fin) {
1024 *off = offset;
1025 return skb;
1026 }
1027 }
1028 return NULL;
1029 }
1030
1031 /*
1032 * This routine provides an alternative to tcp_recvmsg() for routines
1033 * that would like to handle copying from skbuffs directly in 'sendfile'
1034 * fashion.
1035 * Note:
1036 * - It is assumed that the socket was locked by the caller.
1037 * - The routine does not block.
1038 * - At present, there is no support for reading OOB data
1039 * or for 'peeking' the socket using this routine
1040 * (although both would be easy to implement).
1041 */
1042 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1043 sk_read_actor_t recv_actor)
1044 {
1045 struct sk_buff *skb;
1046 struct tcp_sock *tp = tcp_sk(sk);
1047 u32 seq = tp->copied_seq;
1048 u32 offset;
1049 int copied = 0;
1050
1051 if (sk->sk_state == TCP_LISTEN)
1052 return -ENOTCONN;
1053 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1054 if (offset < skb->len) {
1055 size_t used, len;
1056
1057 len = skb->len - offset;
1058 /* Stop reading if we hit a patch of urgent data */
1059 if (tp->urg_data) {
1060 u32 urg_offset = tp->urg_seq - seq;
1061 if (urg_offset < len)
1062 len = urg_offset;
1063 if (!len)
1064 break;
1065 }
1066 used = recv_actor(desc, skb, offset, len);
1067 if (used <= len) {
1068 seq += used;
1069 copied += used;
1070 offset += used;
1071 }
1072 if (offset != skb->len)
1073 break;
1074 }
1075 if (tcp_hdr(skb)->fin) {
1076 sk_eat_skb(sk, skb, 0);
1077 ++seq;
1078 break;
1079 }
1080 sk_eat_skb(sk, skb, 0);
1081 if (!desc->count)
1082 break;
1083 }
1084 tp->copied_seq = seq;
1085
1086 tcp_rcv_space_adjust(sk);
1087
1088 /* Clean up data we have read: This will do ACK frames. */
1089 if (copied)
1090 tcp_cleanup_rbuf(sk, copied);
1091 return copied;
1092 }
1093
1094 /*
1095 * This routine copies from a sock struct into the user buffer.
1096 *
1097 * Technical note: in 2.3 we work on _locked_ socket, so that
1098 * tricks with *seq access order and skb->users are not required.
1099 * Probably, code can be easily improved even more.
1100 */
1101
1102 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1103 size_t len, int nonblock, int flags, int *addr_len)
1104 {
1105 struct tcp_sock *tp = tcp_sk(sk);
1106 int copied = 0;
1107 u32 peek_seq;
1108 u32 *seq;
1109 unsigned long used;
1110 int err;
1111 int target; /* Read at least this many bytes */
1112 long timeo;
1113 struct task_struct *user_recv = NULL;
1114 int copied_early = 0;
1115
1116 lock_sock(sk);
1117
1118 TCP_CHECK_TIMER(sk);
1119
1120 err = -ENOTCONN;
1121 if (sk->sk_state == TCP_LISTEN)
1122 goto out;
1123
1124 timeo = sock_rcvtimeo(sk, nonblock);
1125
1126 /* Urgent data needs to be handled specially. */
1127 if (flags & MSG_OOB)
1128 goto recv_urg;
1129
1130 seq = &tp->copied_seq;
1131 if (flags & MSG_PEEK) {
1132 peek_seq = tp->copied_seq;
1133 seq = &peek_seq;
1134 }
1135
1136 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1137
1138 #ifdef CONFIG_NET_DMA
1139 tp->ucopy.dma_chan = NULL;
1140 preempt_disable();
1141 if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1142 !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) {
1143 preempt_enable_no_resched();
1144 tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len);
1145 } else
1146 preempt_enable_no_resched();
1147 #endif
1148
1149 do {
1150 struct sk_buff *skb;
1151 u32 offset;
1152
1153 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1154 if (tp->urg_data && tp->urg_seq == *seq) {
1155 if (copied)
1156 break;
1157 if (signal_pending(current)) {
1158 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1159 break;
1160 }
1161 }
1162
1163 /* Next get a buffer. */
1164
1165 skb = skb_peek(&sk->sk_receive_queue);
1166 do {
1167 if (!skb)
1168 break;
1169
1170 /* Now that we have two receive queues this
1171 * shouldn't happen.
1172 */
1173 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1174 printk(KERN_INFO "recvmsg bug: copied %X "
1175 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1176 break;
1177 }
1178 offset = *seq - TCP_SKB_CB(skb)->seq;
1179 if (tcp_hdr(skb)->syn)
1180 offset--;
1181 if (offset < skb->len)
1182 goto found_ok_skb;
1183 if (tcp_hdr(skb)->fin)
1184 goto found_fin_ok;
1185 BUG_TRAP(flags & MSG_PEEK);
1186 skb = skb->next;
1187 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1188
1189 /* Well, if we have backlog, try to process it now yet. */
1190
1191 if (copied >= target && !sk->sk_backlog.tail)
1192 break;
1193
1194 if (copied) {
1195 if (sk->sk_err ||
1196 sk->sk_state == TCP_CLOSE ||
1197 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1198 !timeo ||
1199 signal_pending(current) ||
1200 (flags & MSG_PEEK))
1201 break;
1202 } else {
1203 if (sock_flag(sk, SOCK_DONE))
1204 break;
1205
1206 if (sk->sk_err) {
1207 copied = sock_error(sk);
1208 break;
1209 }
1210
1211 if (sk->sk_shutdown & RCV_SHUTDOWN)
1212 break;
1213
1214 if (sk->sk_state == TCP_CLOSE) {
1215 if (!sock_flag(sk, SOCK_DONE)) {
1216 /* This occurs when user tries to read
1217 * from never connected socket.
1218 */
1219 copied = -ENOTCONN;
1220 break;
1221 }
1222 break;
1223 }
1224
1225 if (!timeo) {
1226 copied = -EAGAIN;
1227 break;
1228 }
1229
1230 if (signal_pending(current)) {
1231 copied = sock_intr_errno(timeo);
1232 break;
1233 }
1234 }
1235
1236 tcp_cleanup_rbuf(sk, copied);
1237
1238 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1239 /* Install new reader */
1240 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1241 user_recv = current;
1242 tp->ucopy.task = user_recv;
1243 tp->ucopy.iov = msg->msg_iov;
1244 }
1245
1246 tp->ucopy.len = len;
1247
1248 BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1249 (flags & (MSG_PEEK | MSG_TRUNC)));
1250
1251 /* Ugly... If prequeue is not empty, we have to
1252 * process it before releasing socket, otherwise
1253 * order will be broken at second iteration.
1254 * More elegant solution is required!!!
1255 *
1256 * Look: we have the following (pseudo)queues:
1257 *
1258 * 1. packets in flight
1259 * 2. backlog
1260 * 3. prequeue
1261 * 4. receive_queue
1262 *
1263 * Each queue can be processed only if the next ones
1264 * are empty. At this point we have empty receive_queue.
1265 * But prequeue _can_ be not empty after 2nd iteration,
1266 * when we jumped to start of loop because backlog
1267 * processing added something to receive_queue.
1268 * We cannot release_sock(), because backlog contains
1269 * packets arrived _after_ prequeued ones.
1270 *
1271 * Shortly, algorithm is clear --- to process all
1272 * the queues in order. We could make it more directly,
1273 * requeueing packets from backlog to prequeue, if
1274 * is not empty. It is more elegant, but eats cycles,
1275 * unfortunately.
1276 */
1277 if (!skb_queue_empty(&tp->ucopy.prequeue))
1278 goto do_prequeue;
1279
1280 /* __ Set realtime policy in scheduler __ */
1281 }
1282
1283 if (copied >= target) {
1284 /* Do not sleep, just process backlog. */
1285 release_sock(sk);
1286 lock_sock(sk);
1287 } else
1288 sk_wait_data(sk, &timeo);
1289
1290 #ifdef CONFIG_NET_DMA
1291 tp->ucopy.wakeup = 0;
1292 #endif
1293
1294 if (user_recv) {
1295 int chunk;
1296
1297 /* __ Restore normal policy in scheduler __ */
1298
1299 if ((chunk = len - tp->ucopy.len) != 0) {
1300 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1301 len -= chunk;
1302 copied += chunk;
1303 }
1304
1305 if (tp->rcv_nxt == tp->copied_seq &&
1306 !skb_queue_empty(&tp->ucopy.prequeue)) {
1307 do_prequeue:
1308 tcp_prequeue_process(sk);
1309
1310 if ((chunk = len - tp->ucopy.len) != 0) {
1311 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1312 len -= chunk;
1313 copied += chunk;
1314 }
1315 }
1316 }
1317 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1318 if (net_ratelimit())
1319 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1320 current->comm, current->pid);
1321 peek_seq = tp->copied_seq;
1322 }
1323 continue;
1324
1325 found_ok_skb:
1326 /* Ok so how much can we use? */
1327 used = skb->len - offset;
1328 if (len < used)
1329 used = len;
1330
1331 /* Do we have urgent data here? */
1332 if (tp->urg_data) {
1333 u32 urg_offset = tp->urg_seq - *seq;
1334 if (urg_offset < used) {
1335 if (!urg_offset) {
1336 if (!sock_flag(sk, SOCK_URGINLINE)) {
1337 ++*seq;
1338 offset++;
1339 used--;
1340 if (!used)
1341 goto skip_copy;
1342 }
1343 } else
1344 used = urg_offset;
1345 }
1346 }
1347
1348 if (!(flags & MSG_TRUNC)) {
1349 #ifdef CONFIG_NET_DMA
1350 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1351 tp->ucopy.dma_chan = get_softnet_dma();
1352
1353 if (tp->ucopy.dma_chan) {
1354 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1355 tp->ucopy.dma_chan, skb, offset,
1356 msg->msg_iov, used,
1357 tp->ucopy.pinned_list);
1358
1359 if (tp->ucopy.dma_cookie < 0) {
1360
1361 printk(KERN_ALERT "dma_cookie < 0\n");
1362
1363 /* Exception. Bailout! */
1364 if (!copied)
1365 copied = -EFAULT;
1366 break;
1367 }
1368 if ((offset + used) == skb->len)
1369 copied_early = 1;
1370
1371 } else
1372 #endif
1373 {
1374 err = skb_copy_datagram_iovec(skb, offset,
1375 msg->msg_iov, used);
1376 if (err) {
1377 /* Exception. Bailout! */
1378 if (!copied)
1379 copied = -EFAULT;
1380 break;
1381 }
1382 }
1383 }
1384
1385 *seq += used;
1386 copied += used;
1387 len -= used;
1388
1389 tcp_rcv_space_adjust(sk);
1390
1391 skip_copy:
1392 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1393 tp->urg_data = 0;
1394 tcp_fast_path_check(sk);
1395 }
1396 if (used + offset < skb->len)
1397 continue;
1398
1399 if (tcp_hdr(skb)->fin)
1400 goto found_fin_ok;
1401 if (!(flags & MSG_PEEK)) {
1402 sk_eat_skb(sk, skb, copied_early);
1403 copied_early = 0;
1404 }
1405 continue;
1406
1407 found_fin_ok:
1408 /* Process the FIN. */
1409 ++*seq;
1410 if (!(flags & MSG_PEEK)) {
1411 sk_eat_skb(sk, skb, copied_early);
1412 copied_early = 0;
1413 }
1414 break;
1415 } while (len > 0);
1416
1417 if (user_recv) {
1418 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1419 int chunk;
1420
1421 tp->ucopy.len = copied > 0 ? len : 0;
1422
1423 tcp_prequeue_process(sk);
1424
1425 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1426 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1427 len -= chunk;
1428 copied += chunk;
1429 }
1430 }
1431
1432 tp->ucopy.task = NULL;
1433 tp->ucopy.len = 0;
1434 }
1435
1436 #ifdef CONFIG_NET_DMA
1437 if (tp->ucopy.dma_chan) {
1438 struct sk_buff *skb;
1439 dma_cookie_t done, used;
1440
1441 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1442
1443 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1444 tp->ucopy.dma_cookie, &done,
1445 &used) == DMA_IN_PROGRESS) {
1446 /* do partial cleanup of sk_async_wait_queue */
1447 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1448 (dma_async_is_complete(skb->dma_cookie, done,
1449 used) == DMA_SUCCESS)) {
1450 __skb_dequeue(&sk->sk_async_wait_queue);
1451 kfree_skb(skb);
1452 }
1453 }
1454
1455 /* Safe to free early-copied skbs now */
1456 __skb_queue_purge(&sk->sk_async_wait_queue);
1457 dma_chan_put(tp->ucopy.dma_chan);
1458 tp->ucopy.dma_chan = NULL;
1459 }
1460 if (tp->ucopy.pinned_list) {
1461 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1462 tp->ucopy.pinned_list = NULL;
1463 }
1464 #endif
1465
1466 /* According to UNIX98, msg_name/msg_namelen are ignored
1467 * on connected socket. I was just happy when found this 8) --ANK
1468 */
1469
1470 /* Clean up data we have read: This will do ACK frames. */
1471 tcp_cleanup_rbuf(sk, copied);
1472
1473 TCP_CHECK_TIMER(sk);
1474 release_sock(sk);
1475 return copied;
1476
1477 out:
1478 TCP_CHECK_TIMER(sk);
1479 release_sock(sk);
1480 return err;
1481
1482 recv_urg:
1483 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1484 goto out;
1485 }
1486
1487 /*
1488 * State processing on a close. This implements the state shift for
1489 * sending our FIN frame. Note that we only send a FIN for some
1490 * states. A shutdown() may have already sent the FIN, or we may be
1491 * closed.
1492 */
1493
1494 static const unsigned char new_state[16] = {
1495 /* current state: new state: action: */
1496 /* (Invalid) */ TCP_CLOSE,
1497 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1498 /* TCP_SYN_SENT */ TCP_CLOSE,
1499 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1500 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1501 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1502 /* TCP_TIME_WAIT */ TCP_CLOSE,
1503 /* TCP_CLOSE */ TCP_CLOSE,
1504 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1505 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1506 /* TCP_LISTEN */ TCP_CLOSE,
1507 /* TCP_CLOSING */ TCP_CLOSING,
1508 };
1509
1510 static int tcp_close_state(struct sock *sk)
1511 {
1512 int next = (int)new_state[sk->sk_state];
1513 int ns = next & TCP_STATE_MASK;
1514
1515 tcp_set_state(sk, ns);
1516
1517 return next & TCP_ACTION_FIN;
1518 }
1519
1520 /*
1521 * Shutdown the sending side of a connection. Much like close except
1522 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1523 */
1524
1525 void tcp_shutdown(struct sock *sk, int how)
1526 {
1527 /* We need to grab some memory, and put together a FIN,
1528 * and then put it into the queue to be sent.
1529 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1530 */
1531 if (!(how & SEND_SHUTDOWN))
1532 return;
1533
1534 /* If we've already sent a FIN, or it's a closed state, skip this. */
1535 if ((1 << sk->sk_state) &
1536 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1537 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1538 /* Clear out any half completed packets. FIN if needed. */
1539 if (tcp_close_state(sk))
1540 tcp_send_fin(sk);
1541 }
1542 }
1543
1544 void tcp_close(struct sock *sk, long timeout)
1545 {
1546 struct sk_buff *skb;
1547 int data_was_unread = 0;
1548 int state;
1549
1550 lock_sock(sk);
1551 sk->sk_shutdown = SHUTDOWN_MASK;
1552
1553 if (sk->sk_state == TCP_LISTEN) {
1554 tcp_set_state(sk, TCP_CLOSE);
1555
1556 /* Special case. */
1557 inet_csk_listen_stop(sk);
1558
1559 goto adjudge_to_death;
1560 }
1561
1562 /* We need to flush the recv. buffs. We do this only on the
1563 * descriptor close, not protocol-sourced closes, because the
1564 * reader process may not have drained the data yet!
1565 */
1566 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1567 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1568 tcp_hdr(skb)->fin;
1569 data_was_unread += len;
1570 __kfree_skb(skb);
1571 }
1572
1573 sk_stream_mem_reclaim(sk);
1574
1575 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1576 * data was lost. To witness the awful effects of the old behavior of
1577 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1578 * GET in an FTP client, suspend the process, wait for the client to
1579 * advertise a zero window, then kill -9 the FTP client, wheee...
1580 * Note: timeout is always zero in such a case.
1581 */
1582 if (data_was_unread) {
1583 /* Unread data was tossed, zap the connection. */
1584 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1585 tcp_set_state(sk, TCP_CLOSE);
1586 tcp_send_active_reset(sk, GFP_KERNEL);
1587 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1588 /* Check zero linger _after_ checking for unread data. */
1589 sk->sk_prot->disconnect(sk, 0);
1590 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1591 } else if (tcp_close_state(sk)) {
1592 /* We FIN if the application ate all the data before
1593 * zapping the connection.
1594 */
1595
1596 /* RED-PEN. Formally speaking, we have broken TCP state
1597 * machine. State transitions:
1598 *
1599 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1600 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1601 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1602 *
1603 * are legal only when FIN has been sent (i.e. in window),
1604 * rather than queued out of window. Purists blame.
1605 *
1606 * F.e. "RFC state" is ESTABLISHED,
1607 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1608 *
1609 * The visible declinations are that sometimes
1610 * we enter time-wait state, when it is not required really
1611 * (harmless), do not send active resets, when they are
1612 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1613 * they look as CLOSING or LAST_ACK for Linux)
1614 * Probably, I missed some more holelets.
1615 * --ANK
1616 */
1617 tcp_send_fin(sk);
1618 }
1619
1620 sk_stream_wait_close(sk, timeout);
1621
1622 adjudge_to_death:
1623 state = sk->sk_state;
1624 sock_hold(sk);
1625 sock_orphan(sk);
1626 atomic_inc(sk->sk_prot->orphan_count);
1627
1628 /* It is the last release_sock in its life. It will remove backlog. */
1629 release_sock(sk);
1630
1631
1632 /* Now socket is owned by kernel and we acquire BH lock
1633 to finish close. No need to check for user refs.
1634 */
1635 local_bh_disable();
1636 bh_lock_sock(sk);
1637 BUG_TRAP(!sock_owned_by_user(sk));
1638
1639 /* Have we already been destroyed by a softirq or backlog? */
1640 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1641 goto out;
1642
1643 /* This is a (useful) BSD violating of the RFC. There is a
1644 * problem with TCP as specified in that the other end could
1645 * keep a socket open forever with no application left this end.
1646 * We use a 3 minute timeout (about the same as BSD) then kill
1647 * our end. If they send after that then tough - BUT: long enough
1648 * that we won't make the old 4*rto = almost no time - whoops
1649 * reset mistake.
1650 *
1651 * Nope, it was not mistake. It is really desired behaviour
1652 * f.e. on http servers, when such sockets are useless, but
1653 * consume significant resources. Let's do it with special
1654 * linger2 option. --ANK
1655 */
1656
1657 if (sk->sk_state == TCP_FIN_WAIT2) {
1658 struct tcp_sock *tp = tcp_sk(sk);
1659 if (tp->linger2 < 0) {
1660 tcp_set_state(sk, TCP_CLOSE);
1661 tcp_send_active_reset(sk, GFP_ATOMIC);
1662 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1663 } else {
1664 const int tmo = tcp_fin_time(sk);
1665
1666 if (tmo > TCP_TIMEWAIT_LEN) {
1667 inet_csk_reset_keepalive_timer(sk,
1668 tmo - TCP_TIMEWAIT_LEN);
1669 } else {
1670 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1671 goto out;
1672 }
1673 }
1674 }
1675 if (sk->sk_state != TCP_CLOSE) {
1676 sk_stream_mem_reclaim(sk);
1677 if (atomic_read(sk->sk_prot->orphan_count) > sysctl_tcp_max_orphans ||
1678 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
1679 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) {
1680 if (net_ratelimit())
1681 printk(KERN_INFO "TCP: too many of orphaned "
1682 "sockets\n");
1683 tcp_set_state(sk, TCP_CLOSE);
1684 tcp_send_active_reset(sk, GFP_ATOMIC);
1685 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1686 }
1687 }
1688
1689 if (sk->sk_state == TCP_CLOSE)
1690 inet_csk_destroy_sock(sk);
1691 /* Otherwise, socket is reprieved until protocol close. */
1692
1693 out:
1694 bh_unlock_sock(sk);
1695 local_bh_enable();
1696 sock_put(sk);
1697 }
1698
1699 /* These states need RST on ABORT according to RFC793 */
1700
1701 static inline int tcp_need_reset(int state)
1702 {
1703 return (1 << state) &
1704 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1705 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1706 }
1707
1708 int tcp_disconnect(struct sock *sk, int flags)
1709 {
1710 struct inet_sock *inet = inet_sk(sk);
1711 struct inet_connection_sock *icsk = inet_csk(sk);
1712 struct tcp_sock *tp = tcp_sk(sk);
1713 int err = 0;
1714 int old_state = sk->sk_state;
1715
1716 if (old_state != TCP_CLOSE)
1717 tcp_set_state(sk, TCP_CLOSE);
1718
1719 /* ABORT function of RFC793 */
1720 if (old_state == TCP_LISTEN) {
1721 inet_csk_listen_stop(sk);
1722 } else if (tcp_need_reset(old_state) ||
1723 (tp->snd_nxt != tp->write_seq &&
1724 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1725 /* The last check adjusts for discrepancy of Linux wrt. RFC
1726 * states
1727 */
1728 tcp_send_active_reset(sk, gfp_any());
1729 sk->sk_err = ECONNRESET;
1730 } else if (old_state == TCP_SYN_SENT)
1731 sk->sk_err = ECONNRESET;
1732
1733 tcp_clear_xmit_timers(sk);
1734 __skb_queue_purge(&sk->sk_receive_queue);
1735 tcp_write_queue_purge(sk);
1736 __skb_queue_purge(&tp->out_of_order_queue);
1737 #ifdef CONFIG_NET_DMA
1738 __skb_queue_purge(&sk->sk_async_wait_queue);
1739 #endif
1740
1741 inet->dport = 0;
1742
1743 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1744 inet_reset_saddr(sk);
1745
1746 sk->sk_shutdown = 0;
1747 sock_reset_flag(sk, SOCK_DONE);
1748 tp->srtt = 0;
1749 if ((tp->write_seq += tp->max_window + 2) == 0)
1750 tp->write_seq = 1;
1751 icsk->icsk_backoff = 0;
1752 tp->snd_cwnd = 2;
1753 icsk->icsk_probes_out = 0;
1754 tp->packets_out = 0;
1755 tp->snd_ssthresh = 0x7fffffff;
1756 tp->snd_cwnd_cnt = 0;
1757 tp->bytes_acked = 0;
1758 tcp_set_ca_state(sk, TCP_CA_Open);
1759 tcp_clear_retrans(tp);
1760 inet_csk_delack_init(sk);
1761 tcp_init_send_head(sk);
1762 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
1763 __sk_dst_reset(sk);
1764
1765 BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1766
1767 sk->sk_error_report(sk);
1768 return err;
1769 }
1770
1771 /*
1772 * Socket option code for TCP.
1773 */
1774 static int do_tcp_setsockopt(struct sock *sk, int level,
1775 int optname, char __user *optval, int optlen)
1776 {
1777 struct tcp_sock *tp = tcp_sk(sk);
1778 struct inet_connection_sock *icsk = inet_csk(sk);
1779 int val;
1780 int err = 0;
1781
1782 /* This is a string value all the others are int's */
1783 if (optname == TCP_CONGESTION) {
1784 char name[TCP_CA_NAME_MAX];
1785
1786 if (optlen < 1)
1787 return -EINVAL;
1788
1789 val = strncpy_from_user(name, optval,
1790 min(TCP_CA_NAME_MAX-1, optlen));
1791 if (val < 0)
1792 return -EFAULT;
1793 name[val] = 0;
1794
1795 lock_sock(sk);
1796 err = tcp_set_congestion_control(sk, name);
1797 release_sock(sk);
1798 return err;
1799 }
1800
1801 if (optlen < sizeof(int))
1802 return -EINVAL;
1803
1804 if (get_user(val, (int __user *)optval))
1805 return -EFAULT;
1806
1807 lock_sock(sk);
1808
1809 switch (optname) {
1810 case TCP_MAXSEG:
1811 /* Values greater than interface MTU won't take effect. However
1812 * at the point when this call is done we typically don't yet
1813 * know which interface is going to be used */
1814 if (val < 8 || val > MAX_TCP_WINDOW) {
1815 err = -EINVAL;
1816 break;
1817 }
1818 tp->rx_opt.user_mss = val;
1819 break;
1820
1821 case TCP_NODELAY:
1822 if (val) {
1823 /* TCP_NODELAY is weaker than TCP_CORK, so that
1824 * this option on corked socket is remembered, but
1825 * it is not activated until cork is cleared.
1826 *
1827 * However, when TCP_NODELAY is set we make
1828 * an explicit push, which overrides even TCP_CORK
1829 * for currently queued segments.
1830 */
1831 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
1832 tcp_push_pending_frames(sk);
1833 } else {
1834 tp->nonagle &= ~TCP_NAGLE_OFF;
1835 }
1836 break;
1837
1838 case TCP_CORK:
1839 /* When set indicates to always queue non-full frames.
1840 * Later the user clears this option and we transmit
1841 * any pending partial frames in the queue. This is
1842 * meant to be used alongside sendfile() to get properly
1843 * filled frames when the user (for example) must write
1844 * out headers with a write() call first and then use
1845 * sendfile to send out the data parts.
1846 *
1847 * TCP_CORK can be set together with TCP_NODELAY and it is
1848 * stronger than TCP_NODELAY.
1849 */
1850 if (val) {
1851 tp->nonagle |= TCP_NAGLE_CORK;
1852 } else {
1853 tp->nonagle &= ~TCP_NAGLE_CORK;
1854 if (tp->nonagle&TCP_NAGLE_OFF)
1855 tp->nonagle |= TCP_NAGLE_PUSH;
1856 tcp_push_pending_frames(sk);
1857 }
1858 break;
1859
1860 case TCP_KEEPIDLE:
1861 if (val < 1 || val > MAX_TCP_KEEPIDLE)
1862 err = -EINVAL;
1863 else {
1864 tp->keepalive_time = val * HZ;
1865 if (sock_flag(sk, SOCK_KEEPOPEN) &&
1866 !((1 << sk->sk_state) &
1867 (TCPF_CLOSE | TCPF_LISTEN))) {
1868 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
1869 if (tp->keepalive_time > elapsed)
1870 elapsed = tp->keepalive_time - elapsed;
1871 else
1872 elapsed = 0;
1873 inet_csk_reset_keepalive_timer(sk, elapsed);
1874 }
1875 }
1876 break;
1877 case TCP_KEEPINTVL:
1878 if (val < 1 || val > MAX_TCP_KEEPINTVL)
1879 err = -EINVAL;
1880 else
1881 tp->keepalive_intvl = val * HZ;
1882 break;
1883 case TCP_KEEPCNT:
1884 if (val < 1 || val > MAX_TCP_KEEPCNT)
1885 err = -EINVAL;
1886 else
1887 tp->keepalive_probes = val;
1888 break;
1889 case TCP_SYNCNT:
1890 if (val < 1 || val > MAX_TCP_SYNCNT)
1891 err = -EINVAL;
1892 else
1893 icsk->icsk_syn_retries = val;
1894 break;
1895
1896 case TCP_LINGER2:
1897 if (val < 0)
1898 tp->linger2 = -1;
1899 else if (val > sysctl_tcp_fin_timeout / HZ)
1900 tp->linger2 = 0;
1901 else
1902 tp->linger2 = val * HZ;
1903 break;
1904
1905 case TCP_DEFER_ACCEPT:
1906 icsk->icsk_accept_queue.rskq_defer_accept = 0;
1907 if (val > 0) {
1908 /* Translate value in seconds to number of
1909 * retransmits */
1910 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
1911 val > ((TCP_TIMEOUT_INIT / HZ) <<
1912 icsk->icsk_accept_queue.rskq_defer_accept))
1913 icsk->icsk_accept_queue.rskq_defer_accept++;
1914 icsk->icsk_accept_queue.rskq_defer_accept++;
1915 }
1916 break;
1917
1918 case TCP_WINDOW_CLAMP:
1919 if (!val) {
1920 if (sk->sk_state != TCP_CLOSE) {
1921 err = -EINVAL;
1922 break;
1923 }
1924 tp->window_clamp = 0;
1925 } else
1926 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
1927 SOCK_MIN_RCVBUF / 2 : val;
1928 break;
1929
1930 case TCP_QUICKACK:
1931 if (!val) {
1932 icsk->icsk_ack.pingpong = 1;
1933 } else {
1934 icsk->icsk_ack.pingpong = 0;
1935 if ((1 << sk->sk_state) &
1936 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
1937 inet_csk_ack_scheduled(sk)) {
1938 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
1939 tcp_cleanup_rbuf(sk, 1);
1940 if (!(val & 1))
1941 icsk->icsk_ack.pingpong = 1;
1942 }
1943 }
1944 break;
1945
1946 #ifdef CONFIG_TCP_MD5SIG
1947 case TCP_MD5SIG:
1948 /* Read the IP->Key mappings from userspace */
1949 err = tp->af_specific->md5_parse(sk, optval, optlen);
1950 break;
1951 #endif
1952
1953 default:
1954 err = -ENOPROTOOPT;
1955 break;
1956 }
1957
1958 release_sock(sk);
1959 return err;
1960 }
1961
1962 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
1963 int optlen)
1964 {
1965 struct inet_connection_sock *icsk = inet_csk(sk);
1966
1967 if (level != SOL_TCP)
1968 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1969 optval, optlen);
1970 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1971 }
1972
1973 #ifdef CONFIG_COMPAT
1974 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
1975 char __user *optval, int optlen)
1976 {
1977 if (level != SOL_TCP)
1978 return inet_csk_compat_setsockopt(sk, level, optname,
1979 optval, optlen);
1980 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1981 }
1982
1983 EXPORT_SYMBOL(compat_tcp_setsockopt);
1984 #endif
1985
1986 /* Return information about state of tcp endpoint in API format. */
1987 void tcp_get_info(struct sock *sk, struct tcp_info *info)
1988 {
1989 struct tcp_sock *tp = tcp_sk(sk);
1990 const struct inet_connection_sock *icsk = inet_csk(sk);
1991 u32 now = tcp_time_stamp;
1992
1993 memset(info, 0, sizeof(*info));
1994
1995 info->tcpi_state = sk->sk_state;
1996 info->tcpi_ca_state = icsk->icsk_ca_state;
1997 info->tcpi_retransmits = icsk->icsk_retransmits;
1998 info->tcpi_probes = icsk->icsk_probes_out;
1999 info->tcpi_backoff = icsk->icsk_backoff;
2000
2001 if (tp->rx_opt.tstamp_ok)
2002 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2003 if (tp->rx_opt.sack_ok)
2004 info->tcpi_options |= TCPI_OPT_SACK;
2005 if (tp->rx_opt.wscale_ok) {
2006 info->tcpi_options |= TCPI_OPT_WSCALE;
2007 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2008 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2009 }
2010
2011 if (tp->ecn_flags&TCP_ECN_OK)
2012 info->tcpi_options |= TCPI_OPT_ECN;
2013
2014 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2015 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2016 info->tcpi_snd_mss = tp->mss_cache;
2017 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2018
2019 info->tcpi_unacked = tp->packets_out;
2020 info->tcpi_sacked = tp->sacked_out;
2021 info->tcpi_lost = tp->lost_out;
2022 info->tcpi_retrans = tp->retrans_out;
2023 info->tcpi_fackets = tp->fackets_out;
2024
2025 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2026 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2027 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2028
2029 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2030 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2031 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2032 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2033 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2034 info->tcpi_snd_cwnd = tp->snd_cwnd;
2035 info->tcpi_advmss = tp->advmss;
2036 info->tcpi_reordering = tp->reordering;
2037
2038 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2039 info->tcpi_rcv_space = tp->rcvq_space.space;
2040
2041 info->tcpi_total_retrans = tp->total_retrans;
2042 }
2043
2044 EXPORT_SYMBOL_GPL(tcp_get_info);
2045
2046 static int do_tcp_getsockopt(struct sock *sk, int level,
2047 int optname, char __user *optval, int __user *optlen)
2048 {
2049 struct inet_connection_sock *icsk = inet_csk(sk);
2050 struct tcp_sock *tp = tcp_sk(sk);
2051 int val, len;
2052
2053 if (get_user(len, optlen))
2054 return -EFAULT;
2055
2056 len = min_t(unsigned int, len, sizeof(int));
2057
2058 if (len < 0)
2059 return -EINVAL;
2060
2061 switch (optname) {
2062 case TCP_MAXSEG:
2063 val = tp->mss_cache;
2064 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2065 val = tp->rx_opt.user_mss;
2066 break;
2067 case TCP_NODELAY:
2068 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2069 break;
2070 case TCP_CORK:
2071 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2072 break;
2073 case TCP_KEEPIDLE:
2074 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2075 break;
2076 case TCP_KEEPINTVL:
2077 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2078 break;
2079 case TCP_KEEPCNT:
2080 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2081 break;
2082 case TCP_SYNCNT:
2083 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2084 break;
2085 case TCP_LINGER2:
2086 val = tp->linger2;
2087 if (val >= 0)
2088 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2089 break;
2090 case TCP_DEFER_ACCEPT:
2091 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2092 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2093 break;
2094 case TCP_WINDOW_CLAMP:
2095 val = tp->window_clamp;
2096 break;
2097 case TCP_INFO: {
2098 struct tcp_info info;
2099
2100 if (get_user(len, optlen))
2101 return -EFAULT;
2102
2103 tcp_get_info(sk, &info);
2104
2105 len = min_t(unsigned int, len, sizeof(info));
2106 if (put_user(len, optlen))
2107 return -EFAULT;
2108 if (copy_to_user(optval, &info, len))
2109 return -EFAULT;
2110 return 0;
2111 }
2112 case TCP_QUICKACK:
2113 val = !icsk->icsk_ack.pingpong;
2114 break;
2115
2116 case TCP_CONGESTION:
2117 if (get_user(len, optlen))
2118 return -EFAULT;
2119 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2120 if (put_user(len, optlen))
2121 return -EFAULT;
2122 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2123 return -EFAULT;
2124 return 0;
2125 default:
2126 return -ENOPROTOOPT;
2127 }
2128
2129 if (put_user(len, optlen))
2130 return -EFAULT;
2131 if (copy_to_user(optval, &val, len))
2132 return -EFAULT;
2133 return 0;
2134 }
2135
2136 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2137 int __user *optlen)
2138 {
2139 struct inet_connection_sock *icsk = inet_csk(sk);
2140
2141 if (level != SOL_TCP)
2142 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2143 optval, optlen);
2144 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2145 }
2146
2147 #ifdef CONFIG_COMPAT
2148 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2149 char __user *optval, int __user *optlen)
2150 {
2151 if (level != SOL_TCP)
2152 return inet_csk_compat_getsockopt(sk, level, optname,
2153 optval, optlen);
2154 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2155 }
2156
2157 EXPORT_SYMBOL(compat_tcp_getsockopt);
2158 #endif
2159
2160 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2161 {
2162 struct sk_buff *segs = ERR_PTR(-EINVAL);
2163 struct tcphdr *th;
2164 unsigned thlen;
2165 unsigned int seq;
2166 __be32 delta;
2167 unsigned int oldlen;
2168 unsigned int len;
2169
2170 if (!pskb_may_pull(skb, sizeof(*th)))
2171 goto out;
2172
2173 th = tcp_hdr(skb);
2174 thlen = th->doff * 4;
2175 if (thlen < sizeof(*th))
2176 goto out;
2177
2178 if (!pskb_may_pull(skb, thlen))
2179 goto out;
2180
2181 oldlen = (u16)~skb->len;
2182 __skb_pull(skb, thlen);
2183
2184 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2185 /* Packet is from an untrusted source, reset gso_segs. */
2186 int type = skb_shinfo(skb)->gso_type;
2187 int mss;
2188
2189 if (unlikely(type &
2190 ~(SKB_GSO_TCPV4 |
2191 SKB_GSO_DODGY |
2192 SKB_GSO_TCP_ECN |
2193 SKB_GSO_TCPV6 |
2194 0) ||
2195 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2196 goto out;
2197
2198 mss = skb_shinfo(skb)->gso_size;
2199 skb_shinfo(skb)->gso_segs = (skb->len + mss - 1) / mss;
2200
2201 segs = NULL;
2202 goto out;
2203 }
2204
2205 segs = skb_segment(skb, features);
2206 if (IS_ERR(segs))
2207 goto out;
2208
2209 len = skb_shinfo(skb)->gso_size;
2210 delta = htonl(oldlen + (thlen + len));
2211
2212 skb = segs;
2213 th = tcp_hdr(skb);
2214 seq = ntohl(th->seq);
2215
2216 do {
2217 th->fin = th->psh = 0;
2218
2219 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2220 (__force u32)delta));
2221 if (skb->ip_summed != CHECKSUM_PARTIAL)
2222 th->check =
2223 csum_fold(csum_partial(skb_transport_header(skb),
2224 thlen, skb->csum));
2225
2226 seq += len;
2227 skb = skb->next;
2228 th = tcp_hdr(skb);
2229
2230 th->seq = htonl(seq);
2231 th->cwr = 0;
2232 } while (skb->next);
2233
2234 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2235 skb->data_len);
2236 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2237 (__force u32)delta));
2238 if (skb->ip_summed != CHECKSUM_PARTIAL)
2239 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2240 thlen, skb->csum));
2241
2242 out:
2243 return segs;
2244 }
2245 EXPORT_SYMBOL(tcp_tso_segment);
2246
2247 #ifdef CONFIG_TCP_MD5SIG
2248 static unsigned long tcp_md5sig_users;
2249 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2250 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2251
2252 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2253 {
2254 int cpu;
2255 for_each_possible_cpu(cpu) {
2256 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2257 if (p) {
2258 if (p->md5_desc.tfm)
2259 crypto_free_hash(p->md5_desc.tfm);
2260 kfree(p);
2261 p = NULL;
2262 }
2263 }
2264 free_percpu(pool);
2265 }
2266
2267 void tcp_free_md5sig_pool(void)
2268 {
2269 struct tcp_md5sig_pool **pool = NULL;
2270
2271 spin_lock_bh(&tcp_md5sig_pool_lock);
2272 if (--tcp_md5sig_users == 0) {
2273 pool = tcp_md5sig_pool;
2274 tcp_md5sig_pool = NULL;
2275 }
2276 spin_unlock_bh(&tcp_md5sig_pool_lock);
2277 if (pool)
2278 __tcp_free_md5sig_pool(pool);
2279 }
2280
2281 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2282
2283 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
2284 {
2285 int cpu;
2286 struct tcp_md5sig_pool **pool;
2287
2288 pool = alloc_percpu(struct tcp_md5sig_pool *);
2289 if (!pool)
2290 return NULL;
2291
2292 for_each_possible_cpu(cpu) {
2293 struct tcp_md5sig_pool *p;
2294 struct crypto_hash *hash;
2295
2296 p = kzalloc(sizeof(*p), GFP_KERNEL);
2297 if (!p)
2298 goto out_free;
2299 *per_cpu_ptr(pool, cpu) = p;
2300
2301 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2302 if (!hash || IS_ERR(hash))
2303 goto out_free;
2304
2305 p->md5_desc.tfm = hash;
2306 }
2307 return pool;
2308 out_free:
2309 __tcp_free_md5sig_pool(pool);
2310 return NULL;
2311 }
2312
2313 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
2314 {
2315 struct tcp_md5sig_pool **pool;
2316 int alloc = 0;
2317
2318 retry:
2319 spin_lock_bh(&tcp_md5sig_pool_lock);
2320 pool = tcp_md5sig_pool;
2321 if (tcp_md5sig_users++ == 0) {
2322 alloc = 1;
2323 spin_unlock_bh(&tcp_md5sig_pool_lock);
2324 } else if (!pool) {
2325 tcp_md5sig_users--;
2326 spin_unlock_bh(&tcp_md5sig_pool_lock);
2327 cpu_relax();
2328 goto retry;
2329 } else
2330 spin_unlock_bh(&tcp_md5sig_pool_lock);
2331
2332 if (alloc) {
2333 /* we cannot hold spinlock here because this may sleep. */
2334 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
2335 spin_lock_bh(&tcp_md5sig_pool_lock);
2336 if (!p) {
2337 tcp_md5sig_users--;
2338 spin_unlock_bh(&tcp_md5sig_pool_lock);
2339 return NULL;
2340 }
2341 pool = tcp_md5sig_pool;
2342 if (pool) {
2343 /* oops, it has already been assigned. */
2344 spin_unlock_bh(&tcp_md5sig_pool_lock);
2345 __tcp_free_md5sig_pool(p);
2346 } else {
2347 tcp_md5sig_pool = pool = p;
2348 spin_unlock_bh(&tcp_md5sig_pool_lock);
2349 }
2350 }
2351 return pool;
2352 }
2353
2354 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2355
2356 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2357 {
2358 struct tcp_md5sig_pool **p;
2359 spin_lock_bh(&tcp_md5sig_pool_lock);
2360 p = tcp_md5sig_pool;
2361 if (p)
2362 tcp_md5sig_users++;
2363 spin_unlock_bh(&tcp_md5sig_pool_lock);
2364 return (p ? *per_cpu_ptr(p, cpu) : NULL);
2365 }
2366
2367 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2368
2369 void __tcp_put_md5sig_pool(void)
2370 {
2371 tcp_free_md5sig_pool();
2372 }
2373
2374 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2375 #endif
2376
2377 void tcp_done(struct sock *sk)
2378 {
2379 if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2380 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
2381
2382 tcp_set_state(sk, TCP_CLOSE);
2383 tcp_clear_xmit_timers(sk);
2384
2385 sk->sk_shutdown = SHUTDOWN_MASK;
2386
2387 if (!sock_flag(sk, SOCK_DEAD))
2388 sk->sk_state_change(sk);
2389 else
2390 inet_csk_destroy_sock(sk);
2391 }
2392 EXPORT_SYMBOL_GPL(tcp_done);
2393
2394 extern void __skb_cb_too_small_for_tcp(int, int);
2395 extern struct tcp_congestion_ops tcp_reno;
2396
2397 static __initdata unsigned long thash_entries;
2398 static int __init set_thash_entries(char *str)
2399 {
2400 if (!str)
2401 return 0;
2402 thash_entries = simple_strtoul(str, &str, 0);
2403 return 1;
2404 }
2405 __setup("thash_entries=", set_thash_entries);
2406
2407 void __init tcp_init(void)
2408 {
2409 struct sk_buff *skb = NULL;
2410 unsigned long limit;
2411 int order, i, max_share;
2412
2413 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2414 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2415 sizeof(skb->cb));
2416
2417 tcp_hashinfo.bind_bucket_cachep =
2418 kmem_cache_create("tcp_bind_bucket",
2419 sizeof(struct inet_bind_bucket), 0,
2420 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
2421
2422 /* Size and allocate the main established and bind bucket
2423 * hash tables.
2424 *
2425 * The methodology is similar to that of the buffer cache.
2426 */
2427 tcp_hashinfo.ehash =
2428 alloc_large_system_hash("TCP established",
2429 sizeof(struct inet_ehash_bucket),
2430 thash_entries,
2431 (num_physpages >= 128 * 1024) ?
2432 13 : 15,
2433 0,
2434 &tcp_hashinfo.ehash_size,
2435 NULL,
2436 0);
2437 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2438 for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2439 rwlock_init(&tcp_hashinfo.ehash[i].lock);
2440 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2441 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain);
2442 }
2443
2444 tcp_hashinfo.bhash =
2445 alloc_large_system_hash("TCP bind",
2446 sizeof(struct inet_bind_hashbucket),
2447 tcp_hashinfo.ehash_size,
2448 (num_physpages >= 128 * 1024) ?
2449 13 : 15,
2450 0,
2451 &tcp_hashinfo.bhash_size,
2452 NULL,
2453 64 * 1024);
2454 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2455 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2456 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2457 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2458 }
2459
2460 /* Try to be a bit smarter and adjust defaults depending
2461 * on available memory.
2462 */
2463 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2464 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2465 order++)
2466 ;
2467 if (order >= 4) {
2468 sysctl_local_port_range[0] = 32768;
2469 sysctl_local_port_range[1] = 61000;
2470 tcp_death_row.sysctl_max_tw_buckets = 180000;
2471 sysctl_tcp_max_orphans = 4096 << (order - 4);
2472 sysctl_max_syn_backlog = 1024;
2473 } else if (order < 3) {
2474 sysctl_local_port_range[0] = 1024 * (3 - order);
2475 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2476 sysctl_tcp_max_orphans >>= (3 - order);
2477 sysctl_max_syn_backlog = 128;
2478 }
2479
2480 /* Set the pressure threshold to be a fraction of global memory that
2481 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2482 * memory, with a floor of 128 pages.
2483 */
2484 limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
2485 limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
2486 limit = max(limit, 128UL);
2487 sysctl_tcp_mem[0] = limit / 4 * 3;
2488 sysctl_tcp_mem[1] = limit;
2489 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
2490
2491 /* Set per-socket limits to no more than 1/128 the pressure threshold */
2492 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2493 max_share = min(4UL*1024*1024, limit);
2494
2495 sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM;
2496 sysctl_tcp_wmem[1] = 16*1024;
2497 sysctl_tcp_wmem[2] = max(64*1024, max_share);
2498
2499 sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM;
2500 sysctl_tcp_rmem[1] = 87380;
2501 sysctl_tcp_rmem[2] = max(87380, max_share);
2502
2503 printk(KERN_INFO "TCP: Hash tables configured "
2504 "(established %d bind %d)\n",
2505 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
2506
2507 tcp_register_congestion_control(&tcp_reno);
2508 }
2509
2510 EXPORT_SYMBOL(tcp_close);
2511 EXPORT_SYMBOL(tcp_disconnect);
2512 EXPORT_SYMBOL(tcp_getsockopt);
2513 EXPORT_SYMBOL(tcp_ioctl);
2514 EXPORT_SYMBOL(tcp_poll);
2515 EXPORT_SYMBOL(tcp_read_sock);
2516 EXPORT_SYMBOL(tcp_recvmsg);
2517 EXPORT_SYMBOL(tcp_sendmsg);
2518 EXPORT_SYMBOL(tcp_sendpage);
2519 EXPORT_SYMBOL(tcp_setsockopt);
2520 EXPORT_SYMBOL(tcp_shutdown);
2521 EXPORT_SYMBOL(tcp_statistics);
Linux 2.6 libata-dev (mirror)