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Merge by hand (conflicts between pending drivers and kfree cleanups)
[mirror_ubuntu-bionic-kernel.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 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 discrepance 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 tcp_set_ca_state(sk, TCP_CA_Open);
1673 tcp_clear_retrans(tp);
1674 inet_csk_delack_init(sk);
1675 sk->sk_send_head = NULL;
1676 tp->rx_opt.saw_tstamp = 0;
1677 tcp_sack_reset(&tp->rx_opt);
1678 __sk_dst_reset(sk);
1679
1680 BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1681
1682 sk->sk_error_report(sk);
1683 return err;
1684 }
1685
1686 /*
1687 * Socket option code for TCP.
1688 */
1689 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
1690 int optlen)
1691 {
1692 struct tcp_sock *tp = tcp_sk(sk);
1693 struct inet_connection_sock *icsk = inet_csk(sk);
1694 int val;
1695 int err = 0;
1696
1697 if (level != SOL_TCP)
1698 return tp->af_specific->setsockopt(sk, level, optname,
1699 optval, optlen);
1700
1701 /* This is a string value all the others are int's */
1702 if (optname == TCP_CONGESTION) {
1703 char name[TCP_CA_NAME_MAX];
1704
1705 if (optlen < 1)
1706 return -EINVAL;
1707
1708 val = strncpy_from_user(name, optval,
1709 min(TCP_CA_NAME_MAX-1, optlen));
1710 if (val < 0)
1711 return -EFAULT;
1712 name[val] = 0;
1713
1714 lock_sock(sk);
1715 err = tcp_set_congestion_control(sk, name);
1716 release_sock(sk);
1717 return err;
1718 }
1719
1720 if (optlen < sizeof(int))
1721 return -EINVAL;
1722
1723 if (get_user(val, (int __user *)optval))
1724 return -EFAULT;
1725
1726 lock_sock(sk);
1727
1728 switch (optname) {
1729 case TCP_MAXSEG:
1730 /* Values greater than interface MTU won't take effect. However
1731 * at the point when this call is done we typically don't yet
1732 * know which interface is going to be used */
1733 if (val < 8 || val > MAX_TCP_WINDOW) {
1734 err = -EINVAL;
1735 break;
1736 }
1737 tp->rx_opt.user_mss = val;
1738 break;
1739
1740 case TCP_NODELAY:
1741 if (val) {
1742 /* TCP_NODELAY is weaker than TCP_CORK, so that
1743 * this option on corked socket is remembered, but
1744 * it is not activated until cork is cleared.
1745 *
1746 * However, when TCP_NODELAY is set we make
1747 * an explicit push, which overrides even TCP_CORK
1748 * for currently queued segments.
1749 */
1750 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
1751 tcp_push_pending_frames(sk, tp);
1752 } else {
1753 tp->nonagle &= ~TCP_NAGLE_OFF;
1754 }
1755 break;
1756
1757 case TCP_CORK:
1758 /* When set indicates to always queue non-full frames.
1759 * Later the user clears this option and we transmit
1760 * any pending partial frames in the queue. This is
1761 * meant to be used alongside sendfile() to get properly
1762 * filled frames when the user (for example) must write
1763 * out headers with a write() call first and then use
1764 * sendfile to send out the data parts.
1765 *
1766 * TCP_CORK can be set together with TCP_NODELAY and it is
1767 * stronger than TCP_NODELAY.
1768 */
1769 if (val) {
1770 tp->nonagle |= TCP_NAGLE_CORK;
1771 } else {
1772 tp->nonagle &= ~TCP_NAGLE_CORK;
1773 if (tp->nonagle&TCP_NAGLE_OFF)
1774 tp->nonagle |= TCP_NAGLE_PUSH;
1775 tcp_push_pending_frames(sk, tp);
1776 }
1777 break;
1778
1779 case TCP_KEEPIDLE:
1780 if (val < 1 || val > MAX_TCP_KEEPIDLE)
1781 err = -EINVAL;
1782 else {
1783 tp->keepalive_time = val * HZ;
1784 if (sock_flag(sk, SOCK_KEEPOPEN) &&
1785 !((1 << sk->sk_state) &
1786 (TCPF_CLOSE | TCPF_LISTEN))) {
1787 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
1788 if (tp->keepalive_time > elapsed)
1789 elapsed = tp->keepalive_time - elapsed;
1790 else
1791 elapsed = 0;
1792 inet_csk_reset_keepalive_timer(sk, elapsed);
1793 }
1794 }
1795 break;
1796 case TCP_KEEPINTVL:
1797 if (val < 1 || val > MAX_TCP_KEEPINTVL)
1798 err = -EINVAL;
1799 else
1800 tp->keepalive_intvl = val * HZ;
1801 break;
1802 case TCP_KEEPCNT:
1803 if (val < 1 || val > MAX_TCP_KEEPCNT)
1804 err = -EINVAL;
1805 else
1806 tp->keepalive_probes = val;
1807 break;
1808 case TCP_SYNCNT:
1809 if (val < 1 || val > MAX_TCP_SYNCNT)
1810 err = -EINVAL;
1811 else
1812 icsk->icsk_syn_retries = val;
1813 break;
1814
1815 case TCP_LINGER2:
1816 if (val < 0)
1817 tp->linger2 = -1;
1818 else if (val > sysctl_tcp_fin_timeout / HZ)
1819 tp->linger2 = 0;
1820 else
1821 tp->linger2 = val * HZ;
1822 break;
1823
1824 case TCP_DEFER_ACCEPT:
1825 icsk->icsk_accept_queue.rskq_defer_accept = 0;
1826 if (val > 0) {
1827 /* Translate value in seconds to number of
1828 * retransmits */
1829 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
1830 val > ((TCP_TIMEOUT_INIT / HZ) <<
1831 icsk->icsk_accept_queue.rskq_defer_accept))
1832 icsk->icsk_accept_queue.rskq_defer_accept++;
1833 icsk->icsk_accept_queue.rskq_defer_accept++;
1834 }
1835 break;
1836
1837 case TCP_WINDOW_CLAMP:
1838 if (!val) {
1839 if (sk->sk_state != TCP_CLOSE) {
1840 err = -EINVAL;
1841 break;
1842 }
1843 tp->window_clamp = 0;
1844 } else
1845 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
1846 SOCK_MIN_RCVBUF / 2 : val;
1847 break;
1848
1849 case TCP_QUICKACK:
1850 if (!val) {
1851 icsk->icsk_ack.pingpong = 1;
1852 } else {
1853 icsk->icsk_ack.pingpong = 0;
1854 if ((1 << sk->sk_state) &
1855 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
1856 inet_csk_ack_scheduled(sk)) {
1857 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
1858 cleanup_rbuf(sk, 1);
1859 if (!(val & 1))
1860 icsk->icsk_ack.pingpong = 1;
1861 }
1862 }
1863 break;
1864
1865 default:
1866 err = -ENOPROTOOPT;
1867 break;
1868 };
1869 release_sock(sk);
1870 return err;
1871 }
1872
1873 /* Return information about state of tcp endpoint in API format. */
1874 void tcp_get_info(struct sock *sk, struct tcp_info *info)
1875 {
1876 struct tcp_sock *tp = tcp_sk(sk);
1877 const struct inet_connection_sock *icsk = inet_csk(sk);
1878 u32 now = tcp_time_stamp;
1879
1880 memset(info, 0, sizeof(*info));
1881
1882 info->tcpi_state = sk->sk_state;
1883 info->tcpi_ca_state = icsk->icsk_ca_state;
1884 info->tcpi_retransmits = icsk->icsk_retransmits;
1885 info->tcpi_probes = icsk->icsk_probes_out;
1886 info->tcpi_backoff = icsk->icsk_backoff;
1887
1888 if (tp->rx_opt.tstamp_ok)
1889 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1890 if (tp->rx_opt.sack_ok)
1891 info->tcpi_options |= TCPI_OPT_SACK;
1892 if (tp->rx_opt.wscale_ok) {
1893 info->tcpi_options |= TCPI_OPT_WSCALE;
1894 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
1895 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
1896 }
1897
1898 if (tp->ecn_flags&TCP_ECN_OK)
1899 info->tcpi_options |= TCPI_OPT_ECN;
1900
1901 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
1902 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
1903 info->tcpi_snd_mss = tp->mss_cache;
1904 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
1905
1906 info->tcpi_unacked = tp->packets_out;
1907 info->tcpi_sacked = tp->sacked_out;
1908 info->tcpi_lost = tp->lost_out;
1909 info->tcpi_retrans = tp->retrans_out;
1910 info->tcpi_fackets = tp->fackets_out;
1911
1912 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
1913 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
1914 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
1915
1916 info->tcpi_pmtu = tp->pmtu_cookie;
1917 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
1918 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
1919 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
1920 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
1921 info->tcpi_snd_cwnd = tp->snd_cwnd;
1922 info->tcpi_advmss = tp->advmss;
1923 info->tcpi_reordering = tp->reordering;
1924
1925 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
1926 info->tcpi_rcv_space = tp->rcvq_space.space;
1927
1928 info->tcpi_total_retrans = tp->total_retrans;
1929 }
1930
1931 EXPORT_SYMBOL_GPL(tcp_get_info);
1932
1933 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
1934 int __user *optlen)
1935 {
1936 struct inet_connection_sock *icsk = inet_csk(sk);
1937 struct tcp_sock *tp = tcp_sk(sk);
1938 int val, len;
1939
1940 if (level != SOL_TCP)
1941 return tp->af_specific->getsockopt(sk, level, optname,
1942 optval, optlen);
1943
1944 if (get_user(len, optlen))
1945 return -EFAULT;
1946
1947 len = min_t(unsigned int, len, sizeof(int));
1948
1949 if (len < 0)
1950 return -EINVAL;
1951
1952 switch (optname) {
1953 case TCP_MAXSEG:
1954 val = tp->mss_cache;
1955 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
1956 val = tp->rx_opt.user_mss;
1957 break;
1958 case TCP_NODELAY:
1959 val = !!(tp->nonagle&TCP_NAGLE_OFF);
1960 break;
1961 case TCP_CORK:
1962 val = !!(tp->nonagle&TCP_NAGLE_CORK);
1963 break;
1964 case TCP_KEEPIDLE:
1965 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
1966 break;
1967 case TCP_KEEPINTVL:
1968 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
1969 break;
1970 case TCP_KEEPCNT:
1971 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
1972 break;
1973 case TCP_SYNCNT:
1974 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
1975 break;
1976 case TCP_LINGER2:
1977 val = tp->linger2;
1978 if (val >= 0)
1979 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
1980 break;
1981 case TCP_DEFER_ACCEPT:
1982 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
1983 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
1984 break;
1985 case TCP_WINDOW_CLAMP:
1986 val = tp->window_clamp;
1987 break;
1988 case TCP_INFO: {
1989 struct tcp_info info;
1990
1991 if (get_user(len, optlen))
1992 return -EFAULT;
1993
1994 tcp_get_info(sk, &info);
1995
1996 len = min_t(unsigned int, len, sizeof(info));
1997 if (put_user(len, optlen))
1998 return -EFAULT;
1999 if (copy_to_user(optval, &info, len))
2000 return -EFAULT;
2001 return 0;
2002 }
2003 case TCP_QUICKACK:
2004 val = !icsk->icsk_ack.pingpong;
2005 break;
2006
2007 case TCP_CONGESTION:
2008 if (get_user(len, optlen))
2009 return -EFAULT;
2010 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2011 if (put_user(len, optlen))
2012 return -EFAULT;
2013 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2014 return -EFAULT;
2015 return 0;
2016 default:
2017 return -ENOPROTOOPT;
2018 };
2019
2020 if (put_user(len, optlen))
2021 return -EFAULT;
2022 if (copy_to_user(optval, &val, len))
2023 return -EFAULT;
2024 return 0;
2025 }
2026
2027
2028 extern void __skb_cb_too_small_for_tcp(int, int);
2029 extern struct tcp_congestion_ops tcp_reno;
2030
2031 static __initdata unsigned long thash_entries;
2032 static int __init set_thash_entries(char *str)
2033 {
2034 if (!str)
2035 return 0;
2036 thash_entries = simple_strtoul(str, &str, 0);
2037 return 1;
2038 }
2039 __setup("thash_entries=", set_thash_entries);
2040
2041 void __init tcp_init(void)
2042 {
2043 struct sk_buff *skb = NULL;
2044 int order, i;
2045
2046 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2047 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2048 sizeof(skb->cb));
2049
2050 tcp_hashinfo.bind_bucket_cachep =
2051 kmem_cache_create("tcp_bind_bucket",
2052 sizeof(struct inet_bind_bucket), 0,
2053 SLAB_HWCACHE_ALIGN, NULL, NULL);
2054 if (!tcp_hashinfo.bind_bucket_cachep)
2055 panic("tcp_init: Cannot alloc tcp_bind_bucket cache.");
2056
2057 /* Size and allocate the main established and bind bucket
2058 * hash tables.
2059 *
2060 * The methodology is similar to that of the buffer cache.
2061 */
2062 tcp_hashinfo.ehash =
2063 alloc_large_system_hash("TCP established",
2064 sizeof(struct inet_ehash_bucket),
2065 thash_entries,
2066 (num_physpages >= 128 * 1024) ?
2067 (25 - PAGE_SHIFT) :
2068 (27 - PAGE_SHIFT),
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 (25 - PAGE_SHIFT) :
2085 (27 - PAGE_SHIFT),
2086 HASH_HIGHMEM,
2087 &tcp_hashinfo.bhash_size,
2088 NULL,
2089 64 * 1024);
2090 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2091 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2092 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2093 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2094 }
2095
2096 /* Try to be a bit smarter and adjust defaults depending
2097 * on available memory.
2098 */
2099 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2100 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2101 order++)
2102 ;
2103 if (order >= 4) {
2104 sysctl_local_port_range[0] = 32768;
2105 sysctl_local_port_range[1] = 61000;
2106 tcp_death_row.sysctl_max_tw_buckets = 180000;
2107 sysctl_tcp_max_orphans = 4096 << (order - 4);
2108 sysctl_max_syn_backlog = 1024;
2109 } else if (order < 3) {
2110 sysctl_local_port_range[0] = 1024 * (3 - order);
2111 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2112 sysctl_tcp_max_orphans >>= (3 - order);
2113 sysctl_max_syn_backlog = 128;
2114 }
2115
2116 sysctl_tcp_mem[0] = 768 << order;
2117 sysctl_tcp_mem[1] = 1024 << order;
2118 sysctl_tcp_mem[2] = 1536 << order;
2119
2120 if (order < 3) {
2121 sysctl_tcp_wmem[2] = 64 * 1024;
2122 sysctl_tcp_rmem[0] = PAGE_SIZE;
2123 sysctl_tcp_rmem[1] = 43689;
2124 sysctl_tcp_rmem[2] = 2 * 43689;
2125 }
2126
2127 printk(KERN_INFO "TCP: Hash tables configured "
2128 "(established %d bind %d)\n",
2129 tcp_hashinfo.ehash_size << 1, tcp_hashinfo.bhash_size);
2130
2131 tcp_register_congestion_control(&tcp_reno);
2132 }
2133
2134 EXPORT_SYMBOL(tcp_close);
2135 EXPORT_SYMBOL(tcp_disconnect);
2136 EXPORT_SYMBOL(tcp_getsockopt);
2137 EXPORT_SYMBOL(tcp_ioctl);
2138 EXPORT_SYMBOL(tcp_poll);
2139 EXPORT_SYMBOL(tcp_read_sock);
2140 EXPORT_SYMBOL(tcp_recvmsg);
2141 EXPORT_SYMBOL(tcp_sendmsg);
2142 EXPORT_SYMBOL(tcp_sendpage);
2143 EXPORT_SYMBOL(tcp_setsockopt);
2144 EXPORT_SYMBOL(tcp_shutdown);
2145 EXPORT_SYMBOL(tcp_statistics);
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