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Merge with /pub/scm/linux/kernel/git/torvalds/linux-2.6.git
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / ipv4 / tcp.c
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * Version: $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Mark Evans, <evansmp@uhura.aston.ac.uk>
13 * Corey Minyard <wf-rch!minyard@relay.EU.net>
14 * Florian La Roche, <flla@stud.uni-sb.de>
15 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
16 * Linus Torvalds, <torvalds@cs.helsinki.fi>
17 * Alan Cox, <gw4pts@gw4pts.ampr.org>
18 * Matthew Dillon, <dillon@apollo.west.oic.com>
19 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
20 * Jorge Cwik, <jorge@laser.satlink.net>
21 *
22 * Fixes:
23 * Alan Cox : Numerous verify_area() calls
24 * Alan Cox : Set the ACK bit on a reset
25 * Alan Cox : Stopped it crashing if it closed while
26 * sk->inuse=1 and was trying to connect
27 * (tcp_err()).
28 * Alan Cox : All icmp error handling was broken
29 * pointers passed where wrong and the
30 * socket was looked up backwards. Nobody
31 * tested any icmp error code obviously.
32 * Alan Cox : tcp_err() now handled properly. It
33 * wakes people on errors. poll
34 * behaves and the icmp error race
35 * has gone by moving it into sock.c
36 * Alan Cox : tcp_send_reset() fixed to work for
37 * everything not just packets for
38 * unknown sockets.
39 * Alan Cox : tcp option processing.
40 * Alan Cox : Reset tweaked (still not 100%) [Had
41 * syn rule wrong]
42 * Herp Rosmanith : More reset fixes
43 * Alan Cox : No longer acks invalid rst frames.
44 * Acking any kind of RST is right out.
45 * Alan Cox : Sets an ignore me flag on an rst
46 * receive otherwise odd bits of prattle
47 * escape still
48 * Alan Cox : Fixed another acking RST frame bug.
49 * Should stop LAN workplace lockups.
50 * Alan Cox : Some tidyups using the new skb list
51 * facilities
52 * Alan Cox : sk->keepopen now seems to work
53 * Alan Cox : Pulls options out correctly on accepts
54 * Alan Cox : Fixed assorted sk->rqueue->next errors
55 * Alan Cox : PSH doesn't end a TCP read. Switched a
56 * bit to skb ops.
57 * Alan Cox : Tidied tcp_data to avoid a potential
58 * nasty.
59 * Alan Cox : Added some better commenting, as the
60 * tcp is hard to follow
61 * Alan Cox : Removed incorrect check for 20 * psh
62 * Michael O'Reilly : ack < copied bug fix.
63 * Johannes Stille : Misc tcp fixes (not all in yet).
64 * Alan Cox : FIN with no memory -> CRASH
65 * Alan Cox : Added socket option proto entries.
66 * Also added awareness of them to accept.
67 * Alan Cox : Added TCP options (SOL_TCP)
68 * Alan Cox : Switched wakeup calls to callbacks,
69 * so the kernel can layer network
70 * sockets.
71 * Alan Cox : Use ip_tos/ip_ttl settings.
72 * Alan Cox : Handle FIN (more) properly (we hope).
73 * Alan Cox : RST frames sent on unsynchronised
74 * state ack error.
75 * Alan Cox : Put in missing check for SYN bit.
76 * Alan Cox : Added tcp_select_window() aka NET2E
77 * window non shrink trick.
78 * Alan Cox : Added a couple of small NET2E timer
79 * fixes
80 * Charles Hedrick : TCP fixes
81 * Toomas Tamm : TCP window fixes
82 * Alan Cox : Small URG fix to rlogin ^C ack fight
83 * Charles Hedrick : Rewrote most of it to actually work
84 * Linus : Rewrote tcp_read() and URG handling
85 * completely
86 * Gerhard Koerting: Fixed some missing timer handling
87 * Matthew Dillon : Reworked TCP machine states as per RFC
88 * Gerhard Koerting: PC/TCP workarounds
89 * Adam Caldwell : Assorted timer/timing errors
90 * Matthew Dillon : Fixed another RST bug
91 * Alan Cox : Move to kernel side addressing changes.
92 * Alan Cox : Beginning work on TCP fastpathing
93 * (not yet usable)
94 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
95 * Alan Cox : TCP fast path debugging
96 * Alan Cox : Window clamping
97 * Michael Riepe : Bug in tcp_check()
98 * Matt Dillon : More TCP improvements and RST bug fixes
99 * Matt Dillon : Yet more small nasties remove from the
100 * TCP code (Be very nice to this man if
101 * tcp finally works 100%) 8)
102 * Alan Cox : BSD accept semantics.
103 * Alan Cox : Reset on closedown bug.
104 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
105 * Michael Pall : Handle poll() after URG properly in
106 * all cases.
107 * Michael Pall : Undo the last fix in tcp_read_urg()
108 * (multi URG PUSH broke rlogin).
109 * Michael Pall : Fix the multi URG PUSH problem in
110 * tcp_readable(), poll() after URG
111 * works now.
112 * Michael Pall : recv(...,MSG_OOB) never blocks in the
113 * BSD api.
114 * Alan Cox : Changed the semantics of sk->socket to
115 * fix a race and a signal problem with
116 * accept() and async I/O.
117 * Alan Cox : Relaxed the rules on tcp_sendto().
118 * Yury Shevchuk : Really fixed accept() blocking problem.
119 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
120 * clients/servers which listen in on
121 * fixed ports.
122 * Alan Cox : Cleaned the above up and shrank it to
123 * a sensible code size.
124 * Alan Cox : Self connect lockup fix.
125 * Alan Cox : No connect to multicast.
126 * Ross Biro : Close unaccepted children on master
127 * socket close.
128 * Alan Cox : Reset tracing code.
129 * Alan Cox : Spurious resets on shutdown.
130 * Alan Cox : Giant 15 minute/60 second timer error
131 * Alan Cox : Small whoops in polling before an
132 * accept.
133 * Alan Cox : Kept the state trace facility since
134 * it's handy for debugging.
135 * Alan Cox : More reset handler fixes.
136 * Alan Cox : Started rewriting the code based on
137 * the RFC's for other useful protocol
138 * references see: Comer, KA9Q NOS, and
139 * for a reference on the difference
140 * between specifications and how BSD
141 * works see the 4.4lite source.
142 * A.N.Kuznetsov : Don't time wait on completion of tidy
143 * close.
144 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
145 * Linus Torvalds : Fixed BSD port reuse to work first syn
146 * Alan Cox : Reimplemented timers as per the RFC
147 * and using multiple timers for sanity.
148 * Alan Cox : Small bug fixes, and a lot of new
149 * comments.
150 * Alan Cox : Fixed dual reader crash by locking
151 * the buffers (much like datagram.c)
152 * Alan Cox : Fixed stuck sockets in probe. A probe
153 * now gets fed up of retrying without
154 * (even a no space) answer.
155 * Alan Cox : Extracted closing code better
156 * Alan Cox : Fixed the closing state machine to
157 * resemble the RFC.
158 * Alan Cox : More 'per spec' fixes.
159 * Jorge Cwik : Even faster checksumming.
160 * Alan Cox : tcp_data() doesn't ack illegal PSH
161 * only frames. At least one pc tcp stack
162 * generates them.
163 * Alan Cox : Cache last socket.
164 * Alan Cox : Per route irtt.
165 * Matt Day : poll()->select() match BSD precisely on error
166 * Alan Cox : New buffers
167 * Marc Tamsky : Various sk->prot->retransmits and
168 * sk->retransmits misupdating fixed.
169 * Fixed tcp_write_timeout: stuck close,
170 * and TCP syn retries gets used now.
171 * Mark Yarvis : In tcp_read_wakeup(), don't send an
172 * ack if state is TCP_CLOSED.
173 * Alan Cox : Look up device on a retransmit - routes may
174 * change. Doesn't yet cope with MSS shrink right
175 * but it's a start!
176 * Marc Tamsky : Closing in closing fixes.
177 * Mike Shaver : RFC1122 verifications.
178 * Alan Cox : rcv_saddr errors.
179 * Alan Cox : Block double connect().
180 * Alan Cox : Small hooks for enSKIP.
181 * Alexey Kuznetsov: Path MTU discovery.
182 * Alan Cox : Support soft errors.
183 * Alan Cox : Fix MTU discovery pathological case
184 * when the remote claims no mtu!
185 * Marc Tamsky : TCP_CLOSE fix.
186 * Colin (G3TNE) : Send a reset on syn ack replies in
187 * window but wrong (fixes NT lpd problems)
188 * Pedro Roque : Better TCP window handling, delayed ack.
189 * Joerg Reuter : No modification of locked buffers in
190 * tcp_do_retransmit()
191 * Eric Schenk : Changed receiver side silly window
192 * avoidance algorithm to BSD style
193 * algorithm. This doubles throughput
194 * against machines running Solaris,
195 * and seems to result in general
196 * improvement.
197 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
198 * Willy Konynenberg : Transparent proxying support.
199 * Mike McLagan : Routing by source
200 * Keith Owens : Do proper merging with partial SKB's in
201 * tcp_do_sendmsg to avoid burstiness.
202 * Eric Schenk : Fix fast close down bug with
203 * shutdown() followed by close().
204 * Andi Kleen : Make poll agree with SIGIO
205 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
206 * lingertime == 0 (RFC 793 ABORT Call)
207 * Hirokazu Takahashi : Use copy_from_user() instead of
208 * csum_and_copy_from_user() if possible.
209 *
210 * This program is free software; you can redistribute it and/or
211 * modify it under the terms of the GNU General Public License
212 * as published by the Free Software Foundation; either version
213 * 2 of the License, or(at your option) any later version.
214 *
215 * Description of States:
216 *
217 * TCP_SYN_SENT sent a connection request, waiting for ack
218 *
219 * TCP_SYN_RECV received a connection request, sent ack,
220 * waiting for final ack in three-way handshake.
221 *
222 * TCP_ESTABLISHED connection established
223 *
224 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
225 * transmission of remaining buffered data
226 *
227 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
228 * to shutdown
229 *
230 * TCP_CLOSING both sides have shutdown but we still have
231 * data we have to finish sending
232 *
233 * TCP_TIME_WAIT timeout to catch resent junk before entering
234 * closed, can only be entered from FIN_WAIT2
235 * or CLOSING. Required because the other end
236 * may not have gotten our last ACK causing it
237 * to retransmit the data packet (which we ignore)
238 *
239 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
240 * us to finish writing our data and to shutdown
241 * (we have to close() to move on to LAST_ACK)
242 *
243 * TCP_LAST_ACK out side has shutdown after remote has
244 * shutdown. There may still be data in our
245 * buffer that we have to finish sending
246 *
247 * TCP_CLOSE socket is finished
248 */
249
250 #include <linux/config.h>
251 #include <linux/module.h>
252 #include <linux/types.h>
253 #include <linux/fcntl.h>
254 #include <linux/poll.h>
255 #include <linux/init.h>
256 #include <linux/smp_lock.h>
257 #include <linux/fs.h>
258 #include <linux/random.h>
259 #include <linux/bootmem.h>
260
261 #include <net/icmp.h>
262 #include <net/tcp.h>
263 #include <net/xfrm.h>
264 #include <net/ip.h>
265
266
267 #include <asm/uaccess.h>
268 #include <asm/ioctls.h>
269
270 int sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
271
272 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly;
273
274 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
275
276 EXPORT_SYMBOL_GPL(tcp_orphan_count);
277
278 int sysctl_tcp_mem[3];
279 int sysctl_tcp_wmem[3] = { 4 * 1024, 16 * 1024, 128 * 1024 };
280 int sysctl_tcp_rmem[3] = { 4 * 1024, 87380, 87380 * 2 };
281
282 EXPORT_SYMBOL(sysctl_tcp_mem);
283 EXPORT_SYMBOL(sysctl_tcp_rmem);
284 EXPORT_SYMBOL(sysctl_tcp_wmem);
285
286 atomic_t tcp_memory_allocated; /* Current allocated memory. */
287 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
288
289 EXPORT_SYMBOL(tcp_memory_allocated);
290 EXPORT_SYMBOL(tcp_sockets_allocated);
291
292 /*
293 * Pressure flag: try to collapse.
294 * Technical note: it is used by multiple contexts non atomically.
295 * All the sk_stream_mem_schedule() is of this nature: accounting
296 * is strict, actions are advisory and have some latency.
297 */
298 int tcp_memory_pressure;
299
300 EXPORT_SYMBOL(tcp_memory_pressure);
301
302 void tcp_enter_memory_pressure(void)
303 {
304 if (!tcp_memory_pressure) {
305 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
306 tcp_memory_pressure = 1;
307 }
308 }
309
310 EXPORT_SYMBOL(tcp_enter_memory_pressure);
311
312 /*
313 * Wait for a TCP event.
314 *
315 * Note that we don't need to lock the socket, as the upper poll layers
316 * take care of normal races (between the test and the event) and we don't
317 * go look at any of the socket buffers directly.
318 */
319 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
320 {
321 unsigned int mask;
322 struct sock *sk = sock->sk;
323 struct tcp_sock *tp = tcp_sk(sk);
324
325 poll_wait(file, sk->sk_sleep, wait);
326 if (sk->sk_state == TCP_LISTEN)
327 return inet_csk_listen_poll(sk);
328
329 /* Socket is not locked. We are protected from async events
330 by poll logic and correct handling of state changes
331 made by another threads is impossible in any case.
332 */
333
334 mask = 0;
335 if (sk->sk_err)
336 mask = POLLERR;
337
338 /*
339 * POLLHUP is certainly not done right. But poll() doesn't
340 * have a notion of HUP in just one direction, and for a
341 * socket the read side is more interesting.
342 *
343 * Some poll() documentation says that POLLHUP is incompatible
344 * with the POLLOUT/POLLWR flags, so somebody should check this
345 * all. But careful, it tends to be safer to return too many
346 * bits than too few, and you can easily break real applications
347 * if you don't tell them that something has hung up!
348 *
349 * Check-me.
350 *
351 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
352 * our fs/select.c). It means that after we received EOF,
353 * poll always returns immediately, making impossible poll() on write()
354 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
355 * if and only if shutdown has been made in both directions.
356 * Actually, it is interesting to look how Solaris and DUX
357 * solve this dilemma. I would prefer, if PULLHUP were maskable,
358 * then we could set it on SND_SHUTDOWN. BTW examples given
359 * in Stevens' books assume exactly this behaviour, it explains
360 * why PULLHUP is incompatible with POLLOUT. --ANK
361 *
362 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
363 * blocking on fresh not-connected or disconnected socket. --ANK
364 */
365 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
366 mask |= POLLHUP;
367 if (sk->sk_shutdown & RCV_SHUTDOWN)
368 mask |= POLLIN | POLLRDNORM;
369
370 /* Connected? */
371 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
372 /* Potential race condition. If read of tp below will
373 * escape above sk->sk_state, we can be illegally awaken
374 * in SYN_* states. */
375 if ((tp->rcv_nxt != tp->copied_seq) &&
376 (tp->urg_seq != tp->copied_seq ||
377 tp->rcv_nxt != tp->copied_seq + 1 ||
378 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
379 mask |= POLLIN | POLLRDNORM;
380
381 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
382 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
383 mask |= POLLOUT | POLLWRNORM;
384 } else { /* send SIGIO later */
385 set_bit(SOCK_ASYNC_NOSPACE,
386 &sk->sk_socket->flags);
387 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
388
389 /* Race breaker. If space is freed after
390 * wspace test but before the flags are set,
391 * IO signal will be lost.
392 */
393 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
394 mask |= POLLOUT | POLLWRNORM;
395 }
396 }
397
398 if (tp->urg_data & TCP_URG_VALID)
399 mask |= POLLPRI;
400 }
401 return mask;
402 }
403
404 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
405 {
406 struct tcp_sock *tp = tcp_sk(sk);
407 int answ;
408
409 switch (cmd) {
410 case SIOCINQ:
411 if (sk->sk_state == TCP_LISTEN)
412 return -EINVAL;
413
414 lock_sock(sk);
415 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
416 answ = 0;
417 else if (sock_flag(sk, SOCK_URGINLINE) ||
418 !tp->urg_data ||
419 before(tp->urg_seq, tp->copied_seq) ||
420 !before(tp->urg_seq, tp->rcv_nxt)) {
421 answ = tp->rcv_nxt - tp->copied_seq;
422
423 /* Subtract 1, if FIN is in queue. */
424 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
425 answ -=
426 ((struct sk_buff *)sk->sk_receive_queue.prev)->h.th->fin;
427 } else
428 answ = tp->urg_seq - tp->copied_seq;
429 release_sock(sk);
430 break;
431 case SIOCATMARK:
432 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
433 break;
434 case SIOCOUTQ:
435 if (sk->sk_state == TCP_LISTEN)
436 return -EINVAL;
437
438 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
439 answ = 0;
440 else
441 answ = tp->write_seq - tp->snd_una;
442 break;
443 default:
444 return -ENOIOCTLCMD;
445 };
446
447 return put_user(answ, (int __user *)arg);
448 }
449
450 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
451 {
452 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
453 tp->pushed_seq = tp->write_seq;
454 }
455
456 static inline int forced_push(struct tcp_sock *tp)
457 {
458 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
459 }
460
461 static inline void skb_entail(struct sock *sk, struct tcp_sock *tp,
462 struct sk_buff *skb)
463 {
464 skb->csum = 0;
465 TCP_SKB_CB(skb)->seq = tp->write_seq;
466 TCP_SKB_CB(skb)->end_seq = tp->write_seq;
467 TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
468 TCP_SKB_CB(skb)->sacked = 0;
469 skb_header_release(skb);
470 __skb_queue_tail(&sk->sk_write_queue, skb);
471 sk_charge_skb(sk, skb);
472 if (!sk->sk_send_head)
473 sk->sk_send_head = 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, struct tcp_sock *tp, int flags,
489 int mss_now, int nonagle)
490 {
491 if (sk->sk_send_head) {
492 struct sk_buff *skb = sk->sk_write_queue.prev;
493 if (!(flags & MSG_MORE) || forced_push(tp))
494 tcp_mark_push(tp, skb);
495 tcp_mark_urg(tp, flags, skb);
496 __tcp_push_pending_frames(sk, tp, mss_now,
497 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
498 }
499 }
500
501 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
502 size_t psize, int flags)
503 {
504 struct tcp_sock *tp = tcp_sk(sk);
505 int mss_now, size_goal;
506 int err;
507 ssize_t copied;
508 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
509
510 /* Wait for a connection to finish. */
511 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
512 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
513 goto out_err;
514
515 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
516
517 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
518 size_goal = tp->xmit_size_goal;
519 copied = 0;
520
521 err = -EPIPE;
522 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
523 goto do_error;
524
525 while (psize > 0) {
526 struct sk_buff *skb = sk->sk_write_queue.prev;
527 struct page *page = pages[poffset / PAGE_SIZE];
528 int copy, i, can_coalesce;
529 int offset = poffset % PAGE_SIZE;
530 int size = min_t(size_t, psize, PAGE_SIZE - offset);
531
532 if (!sk->sk_send_head || (copy = size_goal - skb->len) <= 0) {
533 new_segment:
534 if (!sk_stream_memory_free(sk))
535 goto wait_for_sndbuf;
536
537 skb = sk_stream_alloc_pskb(sk, 0, 0,
538 sk->sk_allocation);
539 if (!skb)
540 goto wait_for_memory;
541
542 skb_entail(sk, tp, skb);
543 copy = size_goal;
544 }
545
546 if (copy > size)
547 copy = size;
548
549 i = skb_shinfo(skb)->nr_frags;
550 can_coalesce = skb_can_coalesce(skb, i, page, offset);
551 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
552 tcp_mark_push(tp, skb);
553 goto new_segment;
554 }
555 if (!sk_stream_wmem_schedule(sk, copy))
556 goto wait_for_memory;
557
558 if (can_coalesce) {
559 skb_shinfo(skb)->frags[i - 1].size += copy;
560 } else {
561 get_page(page);
562 skb_fill_page_desc(skb, i, page, offset, copy);
563 }
564
565 skb->len += copy;
566 skb->data_len += copy;
567 skb->truesize += copy;
568 sk->sk_wmem_queued += copy;
569 sk->sk_forward_alloc -= copy;
570 skb->ip_summed = CHECKSUM_HW;
571 tp->write_seq += copy;
572 TCP_SKB_CB(skb)->end_seq += copy;
573 skb_shinfo(skb)->tso_segs = 0;
574
575 if (!copied)
576 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
577
578 copied += copy;
579 poffset += copy;
580 if (!(psize -= copy))
581 goto out;
582
583 if (skb->len < mss_now || (flags & MSG_OOB))
584 continue;
585
586 if (forced_push(tp)) {
587 tcp_mark_push(tp, skb);
588 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
589 } else if (skb == sk->sk_send_head)
590 tcp_push_one(sk, mss_now);
591 continue;
592
593 wait_for_sndbuf:
594 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
595 wait_for_memory:
596 if (copied)
597 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
598
599 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
600 goto do_error;
601
602 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
603 size_goal = tp->xmit_size_goal;
604 }
605
606 out:
607 if (copied)
608 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
609 return copied;
610
611 do_error:
612 if (copied)
613 goto out;
614 out_err:
615 return sk_stream_error(sk, flags, err);
616 }
617
618 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
619 size_t size, int flags)
620 {
621 ssize_t res;
622 struct sock *sk = sock->sk;
623
624 #define TCP_ZC_CSUM_FLAGS (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)
625
626 if (!(sk->sk_route_caps & NETIF_F_SG) ||
627 !(sk->sk_route_caps & TCP_ZC_CSUM_FLAGS))
628 return sock_no_sendpage(sock, page, offset, size, flags);
629
630 #undef TCP_ZC_CSUM_FLAGS
631
632 lock_sock(sk);
633 TCP_CHECK_TIMER(sk);
634 res = do_tcp_sendpages(sk, &page, offset, size, flags);
635 TCP_CHECK_TIMER(sk);
636 release_sock(sk);
637 return res;
638 }
639
640 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
641 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
642
643 static inline int select_size(struct sock *sk, struct tcp_sock *tp)
644 {
645 int tmp = tp->mss_cache;
646
647 if (sk->sk_route_caps & NETIF_F_SG) {
648 if (sk->sk_route_caps & NETIF_F_TSO)
649 tmp = 0;
650 else {
651 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
652
653 if (tmp >= pgbreak &&
654 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
655 tmp = pgbreak;
656 }
657 }
658
659 return tmp;
660 }
661
662 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
663 size_t size)
664 {
665 struct iovec *iov;
666 struct tcp_sock *tp = tcp_sk(sk);
667 struct sk_buff *skb;
668 int iovlen, flags;
669 int mss_now, size_goal;
670 int err, copied;
671 long timeo;
672
673 lock_sock(sk);
674 TCP_CHECK_TIMER(sk);
675
676 flags = msg->msg_flags;
677 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
678
679 /* Wait for a connection to finish. */
680 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
681 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
682 goto out_err;
683
684 /* This should be in poll */
685 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
686
687 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
688 size_goal = tp->xmit_size_goal;
689
690 /* Ok commence sending. */
691 iovlen = msg->msg_iovlen;
692 iov = msg->msg_iov;
693 copied = 0;
694
695 err = -EPIPE;
696 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
697 goto do_error;
698
699 while (--iovlen >= 0) {
700 int seglen = iov->iov_len;
701 unsigned char __user *from = iov->iov_base;
702
703 iov++;
704
705 while (seglen > 0) {
706 int copy;
707
708 skb = sk->sk_write_queue.prev;
709
710 if (!sk->sk_send_head ||
711 (copy = size_goal - skb->len) <= 0) {
712
713 new_segment:
714 /* Allocate new segment. If the interface is SG,
715 * allocate skb fitting to single page.
716 */
717 if (!sk_stream_memory_free(sk))
718 goto wait_for_sndbuf;
719
720 skb = sk_stream_alloc_pskb(sk, select_size(sk, tp),
721 0, sk->sk_allocation);
722 if (!skb)
723 goto wait_for_memory;
724
725 /*
726 * Check whether we can use HW checksum.
727 */
728 if (sk->sk_route_caps &
729 (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM |
730 NETIF_F_HW_CSUM))
731 skb->ip_summed = CHECKSUM_HW;
732
733 skb_entail(sk, tp, skb);
734 copy = size_goal;
735 }
736
737 /* Try to append data to the end of skb. */
738 if (copy > seglen)
739 copy = seglen;
740
741 /* Where to copy to? */
742 if (skb_tailroom(skb) > 0) {
743 /* We have some space in skb head. Superb! */
744 if (copy > skb_tailroom(skb))
745 copy = skb_tailroom(skb);
746 if ((err = skb_add_data(skb, from, copy)) != 0)
747 goto do_fault;
748 } else {
749 int merge = 0;
750 int i = skb_shinfo(skb)->nr_frags;
751 struct page *page = TCP_PAGE(sk);
752 int off = TCP_OFF(sk);
753
754 if (skb_can_coalesce(skb, i, page, off) &&
755 off != PAGE_SIZE) {
756 /* We can extend the last page
757 * fragment. */
758 merge = 1;
759 } else if (i == MAX_SKB_FRAGS ||
760 (!i &&
761 !(sk->sk_route_caps & NETIF_F_SG))) {
762 /* Need to add new fragment and cannot
763 * do this because interface is non-SG,
764 * or because all the page slots are
765 * busy. */
766 tcp_mark_push(tp, skb);
767 goto new_segment;
768 } else if (page) {
769 if (off == PAGE_SIZE) {
770 put_page(page);
771 TCP_PAGE(sk) = page = NULL;
772 off = 0;
773 }
774 } else
775 off = 0;
776
777 if (copy > PAGE_SIZE - off)
778 copy = PAGE_SIZE - off;
779
780 if (!sk_stream_wmem_schedule(sk, copy))
781 goto wait_for_memory;
782
783 if (!page) {
784 /* Allocate new cache page. */
785 if (!(page = sk_stream_alloc_page(sk)))
786 goto wait_for_memory;
787 }
788
789 /* Time to copy data. We are close to
790 * the end! */
791 err = skb_copy_to_page(sk, from, skb, page,
792 off, copy);
793 if (err) {
794 /* If this page was new, give it to the
795 * socket so it does not get leaked.
796 */
797 if (!TCP_PAGE(sk)) {
798 TCP_PAGE(sk) = page;
799 TCP_OFF(sk) = 0;
800 }
801 goto do_error;
802 }
803
804 /* Update the skb. */
805 if (merge) {
806 skb_shinfo(skb)->frags[i - 1].size +=
807 copy;
808 } else {
809 skb_fill_page_desc(skb, i, page, off, copy);
810 if (TCP_PAGE(sk)) {
811 get_page(page);
812 } else if (off + copy < PAGE_SIZE) {
813 get_page(page);
814 TCP_PAGE(sk) = page;
815 }
816 }
817
818 TCP_OFF(sk) = off + copy;
819 }
820
821 if (!copied)
822 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
823
824 tp->write_seq += copy;
825 TCP_SKB_CB(skb)->end_seq += copy;
826 skb_shinfo(skb)->tso_segs = 0;
827
828 from += copy;
829 copied += copy;
830 if ((seglen -= copy) == 0 && iovlen == 0)
831 goto out;
832
833 if (skb->len < mss_now || (flags & MSG_OOB))
834 continue;
835
836 if (forced_push(tp)) {
837 tcp_mark_push(tp, skb);
838 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
839 } else if (skb == sk->sk_send_head)
840 tcp_push_one(sk, mss_now);
841 continue;
842
843 wait_for_sndbuf:
844 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
845 wait_for_memory:
846 if (copied)
847 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
848
849 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
850 goto do_error;
851
852 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
853 size_goal = tp->xmit_size_goal;
854 }
855 }
856
857 out:
858 if (copied)
859 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
860 TCP_CHECK_TIMER(sk);
861 release_sock(sk);
862 return copied;
863
864 do_fault:
865 if (!skb->len) {
866 if (sk->sk_send_head == skb)
867 sk->sk_send_head = NULL;
868 __skb_unlink(skb, &sk->sk_write_queue);
869 sk_stream_free_skb(sk, skb);
870 }
871
872 do_error:
873 if (copied)
874 goto out;
875 out_err:
876 err = sk_stream_error(sk, flags, err);
877 TCP_CHECK_TIMER(sk);
878 release_sock(sk);
879 return err;
880 }
881
882 /*
883 * Handle reading urgent data. BSD has very simple semantics for
884 * this, no blocking and very strange errors 8)
885 */
886
887 static int tcp_recv_urg(struct sock *sk, long timeo,
888 struct msghdr *msg, int len, int flags,
889 int *addr_len)
890 {
891 struct tcp_sock *tp = tcp_sk(sk);
892
893 /* No URG data to read. */
894 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
895 tp->urg_data == TCP_URG_READ)
896 return -EINVAL; /* Yes this is right ! */
897
898 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
899 return -ENOTCONN;
900
901 if (tp->urg_data & TCP_URG_VALID) {
902 int err = 0;
903 char c = tp->urg_data;
904
905 if (!(flags & MSG_PEEK))
906 tp->urg_data = TCP_URG_READ;
907
908 /* Read urgent data. */
909 msg->msg_flags |= MSG_OOB;
910
911 if (len > 0) {
912 if (!(flags & MSG_TRUNC))
913 err = memcpy_toiovec(msg->msg_iov, &c, 1);
914 len = 1;
915 } else
916 msg->msg_flags |= MSG_TRUNC;
917
918 return err ? -EFAULT : len;
919 }
920
921 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
922 return 0;
923
924 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
925 * the available implementations agree in this case:
926 * this call should never block, independent of the
927 * blocking state of the socket.
928 * Mike <pall@rz.uni-karlsruhe.de>
929 */
930 return -EAGAIN;
931 }
932
933 /* Clean up the receive buffer for full frames taken by the user,
934 * then send an ACK if necessary. COPIED is the number of bytes
935 * tcp_recvmsg has given to the user so far, it speeds up the
936 * calculation of whether or not we must ACK for the sake of
937 * a window update.
938 */
939 static void cleanup_rbuf(struct sock *sk, int copied)
940 {
941 struct tcp_sock *tp = tcp_sk(sk);
942 int time_to_ack = 0;
943
944 #if TCP_DEBUG
945 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
946
947 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
948 #endif
949
950 if (inet_csk_ack_scheduled(sk)) {
951 const struct inet_connection_sock *icsk = inet_csk(sk);
952 /* Delayed ACKs frequently hit locked sockets during bulk
953 * receive. */
954 if (icsk->icsk_ack.blocked ||
955 /* Once-per-two-segments ACK was not sent by tcp_input.c */
956 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
957 /*
958 * If this read emptied read buffer, we send ACK, if
959 * connection is not bidirectional, user drained
960 * receive buffer and there was a small segment
961 * in queue.
962 */
963 (copied > 0 && (icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
964 !icsk->icsk_ack.pingpong && !atomic_read(&sk->sk_rmem_alloc)))
965 time_to_ack = 1;
966 }
967
968 /* We send an ACK if we can now advertise a non-zero window
969 * which has been raised "significantly".
970 *
971 * Even if window raised up to infinity, do not send window open ACK
972 * in states, where we will not receive more. It is useless.
973 */
974 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
975 __u32 rcv_window_now = tcp_receive_window(tp);
976
977 /* Optimize, __tcp_select_window() is not cheap. */
978 if (2*rcv_window_now <= tp->window_clamp) {
979 __u32 new_window = __tcp_select_window(sk);
980
981 /* Send ACK now, if this read freed lots of space
982 * in our buffer. Certainly, new_window is new window.
983 * We can advertise it now, if it is not less than current one.
984 * "Lots" means "at least twice" here.
985 */
986 if (new_window && new_window >= 2 * rcv_window_now)
987 time_to_ack = 1;
988 }
989 }
990 if (time_to_ack)
991 tcp_send_ack(sk);
992 }
993
994 static void tcp_prequeue_process(struct sock *sk)
995 {
996 struct sk_buff *skb;
997 struct tcp_sock *tp = tcp_sk(sk);
998
999 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
1000
1001 /* RX process wants to run with disabled BHs, though it is not
1002 * necessary */
1003 local_bh_disable();
1004 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1005 sk->sk_backlog_rcv(sk, skb);
1006 local_bh_enable();
1007
1008 /* Clear memory counter. */
1009 tp->ucopy.memory = 0;
1010 }
1011
1012 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1013 {
1014 struct sk_buff *skb;
1015 u32 offset;
1016
1017 skb_queue_walk(&sk->sk_receive_queue, skb) {
1018 offset = seq - TCP_SKB_CB(skb)->seq;
1019 if (skb->h.th->syn)
1020 offset--;
1021 if (offset < skb->len || skb->h.th->fin) {
1022 *off = offset;
1023 return skb;
1024 }
1025 }
1026 return NULL;
1027 }
1028
1029 /*
1030 * This routine provides an alternative to tcp_recvmsg() for routines
1031 * that would like to handle copying from skbuffs directly in 'sendfile'
1032 * fashion.
1033 * Note:
1034 * - It is assumed that the socket was locked by the caller.
1035 * - The routine does not block.
1036 * - At present, there is no support for reading OOB data
1037 * or for 'peeking' the socket using this routine
1038 * (although both would be easy to implement).
1039 */
1040 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1041 sk_read_actor_t recv_actor)
1042 {
1043 struct sk_buff *skb;
1044 struct tcp_sock *tp = tcp_sk(sk);
1045 u32 seq = tp->copied_seq;
1046 u32 offset;
1047 int copied = 0;
1048
1049 if (sk->sk_state == TCP_LISTEN)
1050 return -ENOTCONN;
1051 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1052 if (offset < skb->len) {
1053 size_t used, len;
1054
1055 len = skb->len - offset;
1056 /* Stop reading if we hit a patch of urgent data */
1057 if (tp->urg_data) {
1058 u32 urg_offset = tp->urg_seq - seq;
1059 if (urg_offset < len)
1060 len = urg_offset;
1061 if (!len)
1062 break;
1063 }
1064 used = recv_actor(desc, skb, offset, len);
1065 if (used <= len) {
1066 seq += used;
1067 copied += used;
1068 offset += used;
1069 }
1070 if (offset != skb->len)
1071 break;
1072 }
1073 if (skb->h.th->fin) {
1074 sk_eat_skb(sk, skb);
1075 ++seq;
1076 break;
1077 }
1078 sk_eat_skb(sk, skb);
1079 if (!desc->count)
1080 break;
1081 }
1082 tp->copied_seq = seq;
1083
1084 tcp_rcv_space_adjust(sk);
1085
1086 /* Clean up data we have read: This will do ACK frames. */
1087 if (copied)
1088 cleanup_rbuf(sk, copied);
1089 return copied;
1090 }
1091
1092 /*
1093 * This routine copies from a sock struct into the user buffer.
1094 *
1095 * Technical note: in 2.3 we work on _locked_ socket, so that
1096 * tricks with *seq access order and skb->users are not required.
1097 * Probably, code can be easily improved even more.
1098 */
1099
1100 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1101 size_t len, int nonblock, int flags, int *addr_len)
1102 {
1103 struct tcp_sock *tp = tcp_sk(sk);
1104 int copied = 0;
1105 u32 peek_seq;
1106 u32 *seq;
1107 unsigned long used;
1108 int err;
1109 int target; /* Read at least this many bytes */
1110 long timeo;
1111 struct task_struct *user_recv = NULL;
1112
1113 lock_sock(sk);
1114
1115 TCP_CHECK_TIMER(sk);
1116
1117 err = -ENOTCONN;
1118 if (sk->sk_state == TCP_LISTEN)
1119 goto out;
1120
1121 timeo = sock_rcvtimeo(sk, nonblock);
1122
1123 /* Urgent data needs to be handled specially. */
1124 if (flags & MSG_OOB)
1125 goto recv_urg;
1126
1127 seq = &tp->copied_seq;
1128 if (flags & MSG_PEEK) {
1129 peek_seq = tp->copied_seq;
1130 seq = &peek_seq;
1131 }
1132
1133 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1134
1135 do {
1136 struct sk_buff *skb;
1137 u32 offset;
1138
1139 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1140 if (tp->urg_data && tp->urg_seq == *seq) {
1141 if (copied)
1142 break;
1143 if (signal_pending(current)) {
1144 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1145 break;
1146 }
1147 }
1148
1149 /* Next get a buffer. */
1150
1151 skb = skb_peek(&sk->sk_receive_queue);
1152 do {
1153 if (!skb)
1154 break;
1155
1156 /* Now that we have two receive queues this
1157 * shouldn't happen.
1158 */
1159 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1160 printk(KERN_INFO "recvmsg bug: copied %X "
1161 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1162 break;
1163 }
1164 offset = *seq - TCP_SKB_CB(skb)->seq;
1165 if (skb->h.th->syn)
1166 offset--;
1167 if (offset < skb->len)
1168 goto found_ok_skb;
1169 if (skb->h.th->fin)
1170 goto found_fin_ok;
1171 BUG_TRAP(flags & MSG_PEEK);
1172 skb = skb->next;
1173 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1174
1175 /* Well, if we have backlog, try to process it now yet. */
1176
1177 if (copied >= target && !sk->sk_backlog.tail)
1178 break;
1179
1180 if (copied) {
1181 if (sk->sk_err ||
1182 sk->sk_state == TCP_CLOSE ||
1183 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1184 !timeo ||
1185 signal_pending(current) ||
1186 (flags & MSG_PEEK))
1187 break;
1188 } else {
1189 if (sock_flag(sk, SOCK_DONE))
1190 break;
1191
1192 if (sk->sk_err) {
1193 copied = sock_error(sk);
1194 break;
1195 }
1196
1197 if (sk->sk_shutdown & RCV_SHUTDOWN)
1198 break;
1199
1200 if (sk->sk_state == TCP_CLOSE) {
1201 if (!sock_flag(sk, SOCK_DONE)) {
1202 /* This occurs when user tries to read
1203 * from never connected socket.
1204 */
1205 copied = -ENOTCONN;
1206 break;
1207 }
1208 break;
1209 }
1210
1211 if (!timeo) {
1212 copied = -EAGAIN;
1213 break;
1214 }
1215
1216 if (signal_pending(current)) {
1217 copied = sock_intr_errno(timeo);
1218 break;
1219 }
1220 }
1221
1222 cleanup_rbuf(sk, copied);
1223
1224 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1225 /* Install new reader */
1226 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1227 user_recv = current;
1228 tp->ucopy.task = user_recv;
1229 tp->ucopy.iov = msg->msg_iov;
1230 }
1231
1232 tp->ucopy.len = len;
1233
1234 BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1235 (flags & (MSG_PEEK | MSG_TRUNC)));
1236
1237 /* Ugly... If prequeue is not empty, we have to
1238 * process it before releasing socket, otherwise
1239 * order will be broken at second iteration.
1240 * More elegant solution is required!!!
1241 *
1242 * Look: we have the following (pseudo)queues:
1243 *
1244 * 1. packets in flight
1245 * 2. backlog
1246 * 3. prequeue
1247 * 4. receive_queue
1248 *
1249 * Each queue can be processed only if the next ones
1250 * are empty. At this point we have empty receive_queue.
1251 * But prequeue _can_ be not empty after 2nd iteration,
1252 * when we jumped to start of loop because backlog
1253 * processing added something to receive_queue.
1254 * We cannot release_sock(), because backlog contains
1255 * packets arrived _after_ prequeued ones.
1256 *
1257 * Shortly, algorithm is clear --- to process all
1258 * the queues in order. We could make it more directly,
1259 * requeueing packets from backlog to prequeue, if
1260 * is not empty. It is more elegant, but eats cycles,
1261 * unfortunately.
1262 */
1263 if (!skb_queue_empty(&tp->ucopy.prequeue))
1264 goto do_prequeue;
1265
1266 /* __ Set realtime policy in scheduler __ */
1267 }
1268
1269 if (copied >= target) {
1270 /* Do not sleep, just process backlog. */
1271 release_sock(sk);
1272 lock_sock(sk);
1273 } else
1274 sk_wait_data(sk, &timeo);
1275
1276 if (user_recv) {
1277 int chunk;
1278
1279 /* __ Restore normal policy in scheduler __ */
1280
1281 if ((chunk = len - tp->ucopy.len) != 0) {
1282 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1283 len -= chunk;
1284 copied += chunk;
1285 }
1286
1287 if (tp->rcv_nxt == tp->copied_seq &&
1288 !skb_queue_empty(&tp->ucopy.prequeue)) {
1289 do_prequeue:
1290 tcp_prequeue_process(sk);
1291
1292 if ((chunk = len - tp->ucopy.len) != 0) {
1293 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1294 len -= chunk;
1295 copied += chunk;
1296 }
1297 }
1298 }
1299 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1300 if (net_ratelimit())
1301 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1302 current->comm, current->pid);
1303 peek_seq = tp->copied_seq;
1304 }
1305 continue;
1306
1307 found_ok_skb:
1308 /* Ok so how much can we use? */
1309 used = skb->len - offset;
1310 if (len < used)
1311 used = len;
1312
1313 /* Do we have urgent data here? */
1314 if (tp->urg_data) {
1315 u32 urg_offset = tp->urg_seq - *seq;
1316 if (urg_offset < used) {
1317 if (!urg_offset) {
1318 if (!sock_flag(sk, SOCK_URGINLINE)) {
1319 ++*seq;
1320 offset++;
1321 used--;
1322 if (!used)
1323 goto skip_copy;
1324 }
1325 } else
1326 used = urg_offset;
1327 }
1328 }
1329
1330 if (!(flags & MSG_TRUNC)) {
1331 err = skb_copy_datagram_iovec(skb, offset,
1332 msg->msg_iov, used);
1333 if (err) {
1334 /* Exception. Bailout! */
1335 if (!copied)
1336 copied = -EFAULT;
1337 break;
1338 }
1339 }
1340
1341 *seq += used;
1342 copied += used;
1343 len -= used;
1344
1345 tcp_rcv_space_adjust(sk);
1346
1347 skip_copy:
1348 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1349 tp->urg_data = 0;
1350 tcp_fast_path_check(sk, tp);
1351 }
1352 if (used + offset < skb->len)
1353 continue;
1354
1355 if (skb->h.th->fin)
1356 goto found_fin_ok;
1357 if (!(flags & MSG_PEEK))
1358 sk_eat_skb(sk, skb);
1359 continue;
1360
1361 found_fin_ok:
1362 /* Process the FIN. */
1363 ++*seq;
1364 if (!(flags & MSG_PEEK))
1365 sk_eat_skb(sk, skb);
1366 break;
1367 } while (len > 0);
1368
1369 if (user_recv) {
1370 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1371 int chunk;
1372
1373 tp->ucopy.len = copied > 0 ? len : 0;
1374
1375 tcp_prequeue_process(sk);
1376
1377 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1378 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1379 len -= chunk;
1380 copied += chunk;
1381 }
1382 }
1383
1384 tp->ucopy.task = NULL;
1385 tp->ucopy.len = 0;
1386 }
1387
1388 /* According to UNIX98, msg_name/msg_namelen are ignored
1389 * on connected socket. I was just happy when found this 8) --ANK
1390 */
1391
1392 /* Clean up data we have read: This will do ACK frames. */
1393 cleanup_rbuf(sk, copied);
1394
1395 TCP_CHECK_TIMER(sk);
1396 release_sock(sk);
1397 return copied;
1398
1399 out:
1400 TCP_CHECK_TIMER(sk);
1401 release_sock(sk);
1402 return err;
1403
1404 recv_urg:
1405 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1406 goto out;
1407 }
1408
1409 /*
1410 * State processing on a close. This implements the state shift for
1411 * sending our FIN frame. Note that we only send a FIN for some
1412 * states. A shutdown() may have already sent the FIN, or we may be
1413 * closed.
1414 */
1415
1416 static const unsigned char new_state[16] = {
1417 /* current state: new state: action: */
1418 /* (Invalid) */ TCP_CLOSE,
1419 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1420 /* TCP_SYN_SENT */ TCP_CLOSE,
1421 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1422 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1423 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1424 /* TCP_TIME_WAIT */ TCP_CLOSE,
1425 /* TCP_CLOSE */ TCP_CLOSE,
1426 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1427 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1428 /* TCP_LISTEN */ TCP_CLOSE,
1429 /* TCP_CLOSING */ TCP_CLOSING,
1430 };
1431
1432 static int tcp_close_state(struct sock *sk)
1433 {
1434 int next = (int)new_state[sk->sk_state];
1435 int ns = next & TCP_STATE_MASK;
1436
1437 tcp_set_state(sk, ns);
1438
1439 return next & TCP_ACTION_FIN;
1440 }
1441
1442 /*
1443 * Shutdown the sending side of a connection. Much like close except
1444 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1445 */
1446
1447 void tcp_shutdown(struct sock *sk, int how)
1448 {
1449 /* We need to grab some memory, and put together a FIN,
1450 * and then put it into the queue to be sent.
1451 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1452 */
1453 if (!(how & SEND_SHUTDOWN))
1454 return;
1455
1456 /* If we've already sent a FIN, or it's a closed state, skip this. */
1457 if ((1 << sk->sk_state) &
1458 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1459 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1460 /* Clear out any half completed packets. FIN if needed. */
1461 if (tcp_close_state(sk))
1462 tcp_send_fin(sk);
1463 }
1464 }
1465
1466 void tcp_close(struct sock *sk, long timeout)
1467 {
1468 struct sk_buff *skb;
1469 int data_was_unread = 0;
1470
1471 lock_sock(sk);
1472 sk->sk_shutdown = SHUTDOWN_MASK;
1473
1474 if (sk->sk_state == TCP_LISTEN) {
1475 tcp_set_state(sk, TCP_CLOSE);
1476
1477 /* Special case. */
1478 inet_csk_listen_stop(sk);
1479
1480 goto adjudge_to_death;
1481 }
1482
1483 /* We need to flush the recv. buffs. We do this only on the
1484 * descriptor close, not protocol-sourced closes, because the
1485 * reader process may not have drained the data yet!
1486 */
1487 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1488 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1489 skb->h.th->fin;
1490 data_was_unread += len;
1491 __kfree_skb(skb);
1492 }
1493
1494 sk_stream_mem_reclaim(sk);
1495
1496 /* As outlined in draft-ietf-tcpimpl-prob-03.txt, section
1497 * 3.10, we send a RST here because data was lost. To
1498 * witness the awful effects of the old behavior of always
1499 * doing a FIN, run an older 2.1.x kernel or 2.0.x, start
1500 * a bulk GET in an FTP client, suspend the process, wait
1501 * for the client to advertise a zero window, then kill -9
1502 * the FTP client, wheee... Note: timeout is always zero
1503 * in such a case.
1504 */
1505 if (data_was_unread) {
1506 /* Unread data was tossed, zap the connection. */
1507 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1508 tcp_set_state(sk, TCP_CLOSE);
1509 tcp_send_active_reset(sk, GFP_KERNEL);
1510 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1511 /* Check zero linger _after_ checking for unread data. */
1512 sk->sk_prot->disconnect(sk, 0);
1513 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1514 } else if (tcp_close_state(sk)) {
1515 /* We FIN if the application ate all the data before
1516 * zapping the connection.
1517 */
1518
1519 /* RED-PEN. Formally speaking, we have broken TCP state
1520 * machine. State transitions:
1521 *
1522 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1523 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1524 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1525 *
1526 * are legal only when FIN has been sent (i.e. in window),
1527 * rather than queued out of window. Purists blame.
1528 *
1529 * F.e. "RFC state" is ESTABLISHED,
1530 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1531 *
1532 * The visible declinations are that sometimes
1533 * we enter time-wait state, when it is not required really
1534 * (harmless), do not send active resets, when they are
1535 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1536 * they look as CLOSING or LAST_ACK for Linux)
1537 * Probably, I missed some more holelets.
1538 * --ANK
1539 */
1540 tcp_send_fin(sk);
1541 }
1542
1543 sk_stream_wait_close(sk, timeout);
1544
1545 adjudge_to_death:
1546 /* It is the last release_sock in its life. It will remove backlog. */
1547 release_sock(sk);
1548
1549
1550 /* Now socket is owned by kernel and we acquire BH lock
1551 to finish close. No need to check for user refs.
1552 */
1553 local_bh_disable();
1554 bh_lock_sock(sk);
1555 BUG_TRAP(!sock_owned_by_user(sk));
1556
1557 sock_hold(sk);
1558 sock_orphan(sk);
1559
1560 /* This is a (useful) BSD violating of the RFC. There is a
1561 * problem with TCP as specified in that the other end could
1562 * keep a socket open forever with no application left this end.
1563 * We use a 3 minute timeout (about the same as BSD) then kill
1564 * our end. If they send after that then tough - BUT: long enough
1565 * that we won't make the old 4*rto = almost no time - whoops
1566 * reset mistake.
1567 *
1568 * Nope, it was not mistake. It is really desired behaviour
1569 * f.e. on http servers, when such sockets are useless, but
1570 * consume significant resources. Let's do it with special
1571 * linger2 option. --ANK
1572 */
1573
1574 if (sk->sk_state == TCP_FIN_WAIT2) {
1575 struct tcp_sock *tp = tcp_sk(sk);
1576 if (tp->linger2 < 0) {
1577 tcp_set_state(sk, TCP_CLOSE);
1578 tcp_send_active_reset(sk, GFP_ATOMIC);
1579 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1580 } else {
1581 const int tmo = tcp_fin_time(sk);
1582
1583 if (tmo > TCP_TIMEWAIT_LEN) {
1584 inet_csk_reset_keepalive_timer(sk, tcp_fin_time(sk));
1585 } else {
1586 atomic_inc(sk->sk_prot->orphan_count);
1587 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1588 goto out;
1589 }
1590 }
1591 }
1592 if (sk->sk_state != TCP_CLOSE) {
1593 sk_stream_mem_reclaim(sk);
1594 if (atomic_read(sk->sk_prot->orphan_count) > sysctl_tcp_max_orphans ||
1595 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
1596 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) {
1597 if (net_ratelimit())
1598 printk(KERN_INFO "TCP: too many of orphaned "
1599 "sockets\n");
1600 tcp_set_state(sk, TCP_CLOSE);
1601 tcp_send_active_reset(sk, GFP_ATOMIC);
1602 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1603 }
1604 }
1605 atomic_inc(sk->sk_prot->orphan_count);
1606
1607 if (sk->sk_state == TCP_CLOSE)
1608 inet_csk_destroy_sock(sk);
1609 /* Otherwise, socket is reprieved until protocol close. */
1610
1611 out:
1612 bh_unlock_sock(sk);
1613 local_bh_enable();
1614 sock_put(sk);
1615 }
1616
1617 /* These states need RST on ABORT according to RFC793 */
1618
1619 static inline int tcp_need_reset(int state)
1620 {
1621 return (1 << state) &
1622 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1623 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1624 }
1625
1626 int tcp_disconnect(struct sock *sk, int flags)
1627 {
1628 struct inet_sock *inet = inet_sk(sk);
1629 struct inet_connection_sock *icsk = inet_csk(sk);
1630 struct tcp_sock *tp = tcp_sk(sk);
1631 int err = 0;
1632 int old_state = sk->sk_state;
1633
1634 if (old_state != TCP_CLOSE)
1635 tcp_set_state(sk, TCP_CLOSE);
1636
1637 /* ABORT function of RFC793 */
1638 if (old_state == TCP_LISTEN) {
1639 inet_csk_listen_stop(sk);
1640 } else if (tcp_need_reset(old_state) ||
1641 (tp->snd_nxt != tp->write_seq &&
1642 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1643 /* The last check adjusts for discrepancy of Linux wrt. RFC
1644 * states
1645 */
1646 tcp_send_active_reset(sk, gfp_any());
1647 sk->sk_err = ECONNRESET;
1648 } else if (old_state == TCP_SYN_SENT)
1649 sk->sk_err = ECONNRESET;
1650
1651 tcp_clear_xmit_timers(sk);
1652 __skb_queue_purge(&sk->sk_receive_queue);
1653 sk_stream_writequeue_purge(sk);
1654 __skb_queue_purge(&tp->out_of_order_queue);
1655
1656 inet->dport = 0;
1657
1658 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1659 inet_reset_saddr(sk);
1660
1661 sk->sk_shutdown = 0;
1662 sock_reset_flag(sk, SOCK_DONE);
1663 tp->srtt = 0;
1664 if ((tp->write_seq += tp->max_window + 2) == 0)
1665 tp->write_seq = 1;
1666 icsk->icsk_backoff = 0;
1667 tp->snd_cwnd = 2;
1668 icsk->icsk_probes_out = 0;
1669 tp->packets_out = 0;
1670 tp->snd_ssthresh = 0x7fffffff;
1671 tp->snd_cwnd_cnt = 0;
1672 tp->bytes_acked = 0;
1673 tcp_set_ca_state(sk, TCP_CA_Open);
1674 tcp_clear_retrans(tp);
1675 inet_csk_delack_init(sk);
1676 sk->sk_send_head = NULL;
1677 tp->rx_opt.saw_tstamp = 0;
1678 tcp_sack_reset(&tp->rx_opt);
1679 __sk_dst_reset(sk);
1680
1681 BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1682
1683 sk->sk_error_report(sk);
1684 return err;
1685 }
1686
1687 /*
1688 * Socket option code for TCP.
1689 */
1690 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
1691 int optlen)
1692 {
1693 struct tcp_sock *tp = tcp_sk(sk);
1694 struct inet_connection_sock *icsk = inet_csk(sk);
1695 int val;
1696 int err = 0;
1697
1698 if (level != SOL_TCP)
1699 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1700 optval, optlen);
1701
1702 /* This is a string value all the others are int's */
1703 if (optname == TCP_CONGESTION) {
1704 char name[TCP_CA_NAME_MAX];
1705
1706 if (optlen < 1)
1707 return -EINVAL;
1708
1709 val = strncpy_from_user(name, optval,
1710 min(TCP_CA_NAME_MAX-1, optlen));
1711 if (val < 0)
1712 return -EFAULT;
1713 name[val] = 0;
1714
1715 lock_sock(sk);
1716 err = tcp_set_congestion_control(sk, name);
1717 release_sock(sk);
1718 return err;
1719 }
1720
1721 if (optlen < sizeof(int))
1722 return -EINVAL;
1723
1724 if (get_user(val, (int __user *)optval))
1725 return -EFAULT;
1726
1727 lock_sock(sk);
1728
1729 switch (optname) {
1730 case TCP_MAXSEG:
1731 /* Values greater than interface MTU won't take effect. However
1732 * at the point when this call is done we typically don't yet
1733 * know which interface is going to be used */
1734 if (val < 8 || val > MAX_TCP_WINDOW) {
1735 err = -EINVAL;
1736 break;
1737 }
1738 tp->rx_opt.user_mss = val;
1739 break;
1740
1741 case TCP_NODELAY:
1742 if (val) {
1743 /* TCP_NODELAY is weaker than TCP_CORK, so that
1744 * this option on corked socket is remembered, but
1745 * it is not activated until cork is cleared.
1746 *
1747 * However, when TCP_NODELAY is set we make
1748 * an explicit push, which overrides even TCP_CORK
1749 * for currently queued segments.
1750 */
1751 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
1752 tcp_push_pending_frames(sk, tp);
1753 } else {
1754 tp->nonagle &= ~TCP_NAGLE_OFF;
1755 }
1756 break;
1757
1758 case TCP_CORK:
1759 /* When set indicates to always queue non-full frames.
1760 * Later the user clears this option and we transmit
1761 * any pending partial frames in the queue. This is
1762 * meant to be used alongside sendfile() to get properly
1763 * filled frames when the user (for example) must write
1764 * out headers with a write() call first and then use
1765 * sendfile to send out the data parts.
1766 *
1767 * TCP_CORK can be set together with TCP_NODELAY and it is
1768 * stronger than TCP_NODELAY.
1769 */
1770 if (val) {
1771 tp->nonagle |= TCP_NAGLE_CORK;
1772 } else {
1773 tp->nonagle &= ~TCP_NAGLE_CORK;
1774 if (tp->nonagle&TCP_NAGLE_OFF)
1775 tp->nonagle |= TCP_NAGLE_PUSH;
1776 tcp_push_pending_frames(sk, tp);
1777 }
1778 break;
1779
1780 case TCP_KEEPIDLE:
1781 if (val < 1 || val > MAX_TCP_KEEPIDLE)
1782 err = -EINVAL;
1783 else {
1784 tp->keepalive_time = val * HZ;
1785 if (sock_flag(sk, SOCK_KEEPOPEN) &&
1786 !((1 << sk->sk_state) &
1787 (TCPF_CLOSE | TCPF_LISTEN))) {
1788 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
1789 if (tp->keepalive_time > elapsed)
1790 elapsed = tp->keepalive_time - elapsed;
1791 else
1792 elapsed = 0;
1793 inet_csk_reset_keepalive_timer(sk, elapsed);
1794 }
1795 }
1796 break;
1797 case TCP_KEEPINTVL:
1798 if (val < 1 || val > MAX_TCP_KEEPINTVL)
1799 err = -EINVAL;
1800 else
1801 tp->keepalive_intvl = val * HZ;
1802 break;
1803 case TCP_KEEPCNT:
1804 if (val < 1 || val > MAX_TCP_KEEPCNT)
1805 err = -EINVAL;
1806 else
1807 tp->keepalive_probes = val;
1808 break;
1809 case TCP_SYNCNT:
1810 if (val < 1 || val > MAX_TCP_SYNCNT)
1811 err = -EINVAL;
1812 else
1813 icsk->icsk_syn_retries = val;
1814 break;
1815
1816 case TCP_LINGER2:
1817 if (val < 0)
1818 tp->linger2 = -1;
1819 else if (val > sysctl_tcp_fin_timeout / HZ)
1820 tp->linger2 = 0;
1821 else
1822 tp->linger2 = val * HZ;
1823 break;
1824
1825 case TCP_DEFER_ACCEPT:
1826 icsk->icsk_accept_queue.rskq_defer_accept = 0;
1827 if (val > 0) {
1828 /* Translate value in seconds to number of
1829 * retransmits */
1830 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
1831 val > ((TCP_TIMEOUT_INIT / HZ) <<
1832 icsk->icsk_accept_queue.rskq_defer_accept))
1833 icsk->icsk_accept_queue.rskq_defer_accept++;
1834 icsk->icsk_accept_queue.rskq_defer_accept++;
1835 }
1836 break;
1837
1838 case TCP_WINDOW_CLAMP:
1839 if (!val) {
1840 if (sk->sk_state != TCP_CLOSE) {
1841 err = -EINVAL;
1842 break;
1843 }
1844 tp->window_clamp = 0;
1845 } else
1846 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
1847 SOCK_MIN_RCVBUF / 2 : val;
1848 break;
1849
1850 case TCP_QUICKACK:
1851 if (!val) {
1852 icsk->icsk_ack.pingpong = 1;
1853 } else {
1854 icsk->icsk_ack.pingpong = 0;
1855 if ((1 << sk->sk_state) &
1856 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
1857 inet_csk_ack_scheduled(sk)) {
1858 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
1859 cleanup_rbuf(sk, 1);
1860 if (!(val & 1))
1861 icsk->icsk_ack.pingpong = 1;
1862 }
1863 }
1864 break;
1865
1866 default:
1867 err = -ENOPROTOOPT;
1868 break;
1869 };
1870 release_sock(sk);
1871 return err;
1872 }
1873
1874 /* Return information about state of tcp endpoint in API format. */
1875 void tcp_get_info(struct sock *sk, struct tcp_info *info)
1876 {
1877 struct tcp_sock *tp = tcp_sk(sk);
1878 const struct inet_connection_sock *icsk = inet_csk(sk);
1879 u32 now = tcp_time_stamp;
1880
1881 memset(info, 0, sizeof(*info));
1882
1883 info->tcpi_state = sk->sk_state;
1884 info->tcpi_ca_state = icsk->icsk_ca_state;
1885 info->tcpi_retransmits = icsk->icsk_retransmits;
1886 info->tcpi_probes = icsk->icsk_probes_out;
1887 info->tcpi_backoff = icsk->icsk_backoff;
1888
1889 if (tp->rx_opt.tstamp_ok)
1890 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1891 if (tp->rx_opt.sack_ok)
1892 info->tcpi_options |= TCPI_OPT_SACK;
1893 if (tp->rx_opt.wscale_ok) {
1894 info->tcpi_options |= TCPI_OPT_WSCALE;
1895 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
1896 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
1897 }
1898
1899 if (tp->ecn_flags&TCP_ECN_OK)
1900 info->tcpi_options |= TCPI_OPT_ECN;
1901
1902 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
1903 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
1904 info->tcpi_snd_mss = tp->mss_cache;
1905 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
1906
1907 info->tcpi_unacked = tp->packets_out;
1908 info->tcpi_sacked = tp->sacked_out;
1909 info->tcpi_lost = tp->lost_out;
1910 info->tcpi_retrans = tp->retrans_out;
1911 info->tcpi_fackets = tp->fackets_out;
1912
1913 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
1914 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
1915 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
1916
1917 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
1918 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
1919 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
1920 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
1921 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
1922 info->tcpi_snd_cwnd = tp->snd_cwnd;
1923 info->tcpi_advmss = tp->advmss;
1924 info->tcpi_reordering = tp->reordering;
1925
1926 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
1927 info->tcpi_rcv_space = tp->rcvq_space.space;
1928
1929 info->tcpi_total_retrans = tp->total_retrans;
1930 }
1931
1932 EXPORT_SYMBOL_GPL(tcp_get_info);
1933
1934 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
1935 int __user *optlen)
1936 {
1937 struct inet_connection_sock *icsk = inet_csk(sk);
1938 struct tcp_sock *tp = tcp_sk(sk);
1939 int val, len;
1940
1941 if (level != SOL_TCP)
1942 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
1943 optval, optlen);
1944
1945 if (get_user(len, optlen))
1946 return -EFAULT;
1947
1948 len = min_t(unsigned int, len, sizeof(int));
1949
1950 if (len < 0)
1951 return -EINVAL;
1952
1953 switch (optname) {
1954 case TCP_MAXSEG:
1955 val = tp->mss_cache;
1956 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
1957 val = tp->rx_opt.user_mss;
1958 break;
1959 case TCP_NODELAY:
1960 val = !!(tp->nonagle&TCP_NAGLE_OFF);
1961 break;
1962 case TCP_CORK:
1963 val = !!(tp->nonagle&TCP_NAGLE_CORK);
1964 break;
1965 case TCP_KEEPIDLE:
1966 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
1967 break;
1968 case TCP_KEEPINTVL:
1969 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
1970 break;
1971 case TCP_KEEPCNT:
1972 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
1973 break;
1974 case TCP_SYNCNT:
1975 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
1976 break;
1977 case TCP_LINGER2:
1978 val = tp->linger2;
1979 if (val >= 0)
1980 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
1981 break;
1982 case TCP_DEFER_ACCEPT:
1983 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
1984 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
1985 break;
1986 case TCP_WINDOW_CLAMP:
1987 val = tp->window_clamp;
1988 break;
1989 case TCP_INFO: {
1990 struct tcp_info info;
1991
1992 if (get_user(len, optlen))
1993 return -EFAULT;
1994
1995 tcp_get_info(sk, &info);
1996
1997 len = min_t(unsigned int, len, sizeof(info));
1998 if (put_user(len, optlen))
1999 return -EFAULT;
2000 if (copy_to_user(optval, &info, len))
2001 return -EFAULT;
2002 return 0;
2003 }
2004 case TCP_QUICKACK:
2005 val = !icsk->icsk_ack.pingpong;
2006 break;
2007
2008 case TCP_CONGESTION:
2009 if (get_user(len, optlen))
2010 return -EFAULT;
2011 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2012 if (put_user(len, optlen))
2013 return -EFAULT;
2014 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2015 return -EFAULT;
2016 return 0;
2017 default:
2018 return -ENOPROTOOPT;
2019 };
2020
2021 if (put_user(len, optlen))
2022 return -EFAULT;
2023 if (copy_to_user(optval, &val, len))
2024 return -EFAULT;
2025 return 0;
2026 }
2027
2028
2029 extern void __skb_cb_too_small_for_tcp(int, int);
2030 extern struct tcp_congestion_ops tcp_reno;
2031
2032 static __initdata unsigned long thash_entries;
2033 static int __init set_thash_entries(char *str)
2034 {
2035 if (!str)
2036 return 0;
2037 thash_entries = simple_strtoul(str, &str, 0);
2038 return 1;
2039 }
2040 __setup("thash_entries=", set_thash_entries);
2041
2042 void __init tcp_init(void)
2043 {
2044 struct sk_buff *skb = NULL;
2045 int order, i;
2046
2047 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2048 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2049 sizeof(skb->cb));
2050
2051 tcp_hashinfo.bind_bucket_cachep =
2052 kmem_cache_create("tcp_bind_bucket",
2053 sizeof(struct inet_bind_bucket), 0,
2054 SLAB_HWCACHE_ALIGN, NULL, NULL);
2055 if (!tcp_hashinfo.bind_bucket_cachep)
2056 panic("tcp_init: Cannot alloc tcp_bind_bucket cache.");
2057
2058 /* Size and allocate the main established and bind bucket
2059 * hash tables.
2060 *
2061 * The methodology is similar to that of the buffer cache.
2062 */
2063 tcp_hashinfo.ehash =
2064 alloc_large_system_hash("TCP established",
2065 sizeof(struct inet_ehash_bucket),
2066 thash_entries,
2067 (num_physpages >= 128 * 1024) ?
2068 13 : 15,
2069 HASH_HIGHMEM,
2070 &tcp_hashinfo.ehash_size,
2071 NULL,
2072 0);
2073 tcp_hashinfo.ehash_size = (1 << tcp_hashinfo.ehash_size) >> 1;
2074 for (i = 0; i < (tcp_hashinfo.ehash_size << 1); i++) {
2075 rwlock_init(&tcp_hashinfo.ehash[i].lock);
2076 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2077 }
2078
2079 tcp_hashinfo.bhash =
2080 alloc_large_system_hash("TCP bind",
2081 sizeof(struct inet_bind_hashbucket),
2082 tcp_hashinfo.ehash_size,
2083 (num_physpages >= 128 * 1024) ?
2084 13 : 15,
2085 HASH_HIGHMEM,
2086 &tcp_hashinfo.bhash_size,
2087 NULL,
2088 64 * 1024);
2089 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2090 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2091 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2092 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2093 }
2094
2095 /* Try to be a bit smarter and adjust defaults depending
2096 * on available memory.
2097 */
2098 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2099 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2100 order++)
2101 ;
2102 if (order >= 4) {
2103 sysctl_local_port_range[0] = 32768;
2104 sysctl_local_port_range[1] = 61000;
2105 tcp_death_row.sysctl_max_tw_buckets = 180000;
2106 sysctl_tcp_max_orphans = 4096 << (order - 4);
2107 sysctl_max_syn_backlog = 1024;
2108 } else if (order < 3) {
2109 sysctl_local_port_range[0] = 1024 * (3 - order);
2110 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2111 sysctl_tcp_max_orphans >>= (3 - order);
2112 sysctl_max_syn_backlog = 128;
2113 }
2114
2115 sysctl_tcp_mem[0] = 768 << order;
2116 sysctl_tcp_mem[1] = 1024 << order;
2117 sysctl_tcp_mem[2] = 1536 << order;
2118
2119 if (order < 3) {
2120 sysctl_tcp_wmem[2] = 64 * 1024;
2121 sysctl_tcp_rmem[0] = PAGE_SIZE;
2122 sysctl_tcp_rmem[1] = 43689;
2123 sysctl_tcp_rmem[2] = 2 * 43689;
2124 }
2125
2126 printk(KERN_INFO "TCP: Hash tables configured "
2127 "(established %d bind %d)\n",
2128 tcp_hashinfo.ehash_size << 1, tcp_hashinfo.bhash_size);
2129
2130 tcp_register_congestion_control(&tcp_reno);
2131 }
2132
2133 EXPORT_SYMBOL(tcp_close);
2134 EXPORT_SYMBOL(tcp_disconnect);
2135 EXPORT_SYMBOL(tcp_getsockopt);
2136 EXPORT_SYMBOL(tcp_ioctl);
2137 EXPORT_SYMBOL(tcp_poll);
2138 EXPORT_SYMBOL(tcp_read_sock);
2139 EXPORT_SYMBOL(tcp_recvmsg);
2140 EXPORT_SYMBOL(tcp_sendmsg);
2141 EXPORT_SYMBOL(tcp_sendpage);
2142 EXPORT_SYMBOL(tcp_setsockopt);
2143 EXPORT_SYMBOL(tcp_shutdown);
2144 EXPORT_SYMBOL(tcp_statistics);
kernel source for telekom puls (alcatel/mediatek)