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usb-serial: Add support for the Sealevel SeaLINK+8 2038-ROHS device
[linux/fpc-iii.git] / net / ipv4 / tcp.c
blob22ef5f9fd2ff2e92dc4955dc9a2ac450d8a435fa
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 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Mark Evans, <evansmp@uhura.aston.ac.uk>
11 * Corey Minyard <wf-rch!minyard@relay.EU.net>
12 * Florian La Roche, <flla@stud.uni-sb.de>
13 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
14 * Linus Torvalds, <torvalds@cs.helsinki.fi>
15 * Alan Cox, <gw4pts@gw4pts.ampr.org>
16 * Matthew Dillon, <dillon@apollo.west.oic.com>
17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
18 * Jorge Cwik, <jorge@laser.satlink.net>
19 *
20 * Fixes:
21 * Alan Cox : Numerous verify_area() calls
22 * Alan Cox : Set the ACK bit on a reset
23 * Alan Cox : Stopped it crashing if it closed while
24 * sk->inuse=1 and was trying to connect
25 * (tcp_err()).
26 * Alan Cox : All icmp error handling was broken
27 * pointers passed where wrong and the
28 * socket was looked up backwards. Nobody
29 * tested any icmp error code obviously.
30 * Alan Cox : tcp_err() now handled properly. It
31 * wakes people on errors. poll
32 * behaves and the icmp error race
33 * has gone by moving it into sock.c
34 * Alan Cox : tcp_send_reset() fixed to work for
35 * everything not just packets for
36 * unknown sockets.
37 * Alan Cox : tcp option processing.
38 * Alan Cox : Reset tweaked (still not 100%) [Had
39 * syn rule wrong]
40 * Herp Rosmanith : More reset fixes
41 * Alan Cox : No longer acks invalid rst frames.
42 * Acking any kind of RST is right out.
43 * Alan Cox : Sets an ignore me flag on an rst
44 * receive otherwise odd bits of prattle
45 * escape still
46 * Alan Cox : Fixed another acking RST frame bug.
47 * Should stop LAN workplace lockups.
48 * Alan Cox : Some tidyups using the new skb list
49 * facilities
50 * Alan Cox : sk->keepopen now seems to work
51 * Alan Cox : Pulls options out correctly on accepts
52 * Alan Cox : Fixed assorted sk->rqueue->next errors
53 * Alan Cox : PSH doesn't end a TCP read. Switched a
54 * bit to skb ops.
55 * Alan Cox : Tidied tcp_data to avoid a potential
56 * nasty.
57 * Alan Cox : Added some better commenting, as the
58 * tcp is hard to follow
59 * Alan Cox : Removed incorrect check for 20 * psh
60 * Michael O'Reilly : ack < copied bug fix.
61 * Johannes Stille : Misc tcp fixes (not all in yet).
62 * Alan Cox : FIN with no memory -> CRASH
63 * Alan Cox : Added socket option proto entries.
64 * Also added awareness of them to accept.
65 * Alan Cox : Added TCP options (SOL_TCP)
66 * Alan Cox : Switched wakeup calls to callbacks,
67 * so the kernel can layer network
68 * sockets.
69 * Alan Cox : Use ip_tos/ip_ttl settings.
70 * Alan Cox : Handle FIN (more) properly (we hope).
71 * Alan Cox : RST frames sent on unsynchronised
72 * state ack error.
73 * Alan Cox : Put in missing check for SYN bit.
74 * Alan Cox : Added tcp_select_window() aka NET2E
75 * window non shrink trick.
76 * Alan Cox : Added a couple of small NET2E timer
77 * fixes
78 * Charles Hedrick : TCP fixes
79 * Toomas Tamm : TCP window fixes
80 * Alan Cox : Small URG fix to rlogin ^C ack fight
81 * Charles Hedrick : Rewrote most of it to actually work
82 * Linus : Rewrote tcp_read() and URG handling
83 * completely
84 * Gerhard Koerting: Fixed some missing timer handling
85 * Matthew Dillon : Reworked TCP machine states as per RFC
86 * Gerhard Koerting: PC/TCP workarounds
87 * Adam Caldwell : Assorted timer/timing errors
88 * Matthew Dillon : Fixed another RST bug
89 * Alan Cox : Move to kernel side addressing changes.
90 * Alan Cox : Beginning work on TCP fastpathing
91 * (not yet usable)
92 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
93 * Alan Cox : TCP fast path debugging
94 * Alan Cox : Window clamping
95 * Michael Riepe : Bug in tcp_check()
96 * Matt Dillon : More TCP improvements and RST bug fixes
97 * Matt Dillon : Yet more small nasties remove from the
98 * TCP code (Be very nice to this man if
99 * tcp finally works 100%) 8)
100 * Alan Cox : BSD accept semantics.
101 * Alan Cox : Reset on closedown bug.
102 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
103 * Michael Pall : Handle poll() after URG properly in
104 * all cases.
105 * Michael Pall : Undo the last fix in tcp_read_urg()
106 * (multi URG PUSH broke rlogin).
107 * Michael Pall : Fix the multi URG PUSH problem in
108 * tcp_readable(), poll() after URG
109 * works now.
110 * Michael Pall : recv(...,MSG_OOB) never blocks in the
111 * BSD api.
112 * Alan Cox : Changed the semantics of sk->socket to
113 * fix a race and a signal problem with
114 * accept() and async I/O.
115 * Alan Cox : Relaxed the rules on tcp_sendto().
116 * Yury Shevchuk : Really fixed accept() blocking problem.
117 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
118 * clients/servers which listen in on
119 * fixed ports.
120 * Alan Cox : Cleaned the above up and shrank it to
121 * a sensible code size.
122 * Alan Cox : Self connect lockup fix.
123 * Alan Cox : No connect to multicast.
124 * Ross Biro : Close unaccepted children on master
125 * socket close.
126 * Alan Cox : Reset tracing code.
127 * Alan Cox : Spurious resets on shutdown.
128 * Alan Cox : Giant 15 minute/60 second timer error
129 * Alan Cox : Small whoops in polling before an
130 * accept.
131 * Alan Cox : Kept the state trace facility since
132 * it's handy for debugging.
133 * Alan Cox : More reset handler fixes.
134 * Alan Cox : Started rewriting the code based on
135 * the RFC's for other useful protocol
136 * references see: Comer, KA9Q NOS, and
137 * for a reference on the difference
138 * between specifications and how BSD
139 * works see the 4.4lite source.
140 * A.N.Kuznetsov : Don't time wait on completion of tidy
141 * close.
142 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
143 * Linus Torvalds : Fixed BSD port reuse to work first syn
144 * Alan Cox : Reimplemented timers as per the RFC
145 * and using multiple timers for sanity.
146 * Alan Cox : Small bug fixes, and a lot of new
147 * comments.
148 * Alan Cox : Fixed dual reader crash by locking
149 * the buffers (much like datagram.c)
150 * Alan Cox : Fixed stuck sockets in probe. A probe
151 * now gets fed up of retrying without
152 * (even a no space) answer.
153 * Alan Cox : Extracted closing code better
154 * Alan Cox : Fixed the closing state machine to
155 * resemble the RFC.
156 * Alan Cox : More 'per spec' fixes.
157 * Jorge Cwik : Even faster checksumming.
158 * Alan Cox : tcp_data() doesn't ack illegal PSH
159 * only frames. At least one pc tcp stack
160 * generates them.
161 * Alan Cox : Cache last socket.
162 * Alan Cox : Per route irtt.
163 * Matt Day : poll()->select() match BSD precisely on error
164 * Alan Cox : New buffers
165 * Marc Tamsky : Various sk->prot->retransmits and
166 * sk->retransmits misupdating fixed.
167 * Fixed tcp_write_timeout: stuck close,
168 * and TCP syn retries gets used now.
169 * Mark Yarvis : In tcp_read_wakeup(), don't send an
170 * ack if state is TCP_CLOSED.
171 * Alan Cox : Look up device on a retransmit - routes may
172 * change. Doesn't yet cope with MSS shrink right
173 * but it's a start!
174 * Marc Tamsky : Closing in closing fixes.
175 * Mike Shaver : RFC1122 verifications.
176 * Alan Cox : rcv_saddr errors.
177 * Alan Cox : Block double connect().
178 * Alan Cox : Small hooks for enSKIP.
179 * Alexey Kuznetsov: Path MTU discovery.
180 * Alan Cox : Support soft errors.
181 * Alan Cox : Fix MTU discovery pathological case
182 * when the remote claims no mtu!
183 * Marc Tamsky : TCP_CLOSE fix.
184 * Colin (G3TNE) : Send a reset on syn ack replies in
185 * window but wrong (fixes NT lpd problems)
186 * Pedro Roque : Better TCP window handling, delayed ack.
187 * Joerg Reuter : No modification of locked buffers in
188 * tcp_do_retransmit()
189 * Eric Schenk : Changed receiver side silly window
190 * avoidance algorithm to BSD style
191 * algorithm. This doubles throughput
192 * against machines running Solaris,
193 * and seems to result in general
194 * improvement.
195 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
196 * Willy Konynenberg : Transparent proxying support.
197 * Mike McLagan : Routing by source
198 * Keith Owens : Do proper merging with partial SKB's in
199 * tcp_do_sendmsg to avoid burstiness.
200 * Eric Schenk : Fix fast close down bug with
201 * shutdown() followed by close().
202 * Andi Kleen : Make poll agree with SIGIO
203 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
204 * lingertime == 0 (RFC 793 ABORT Call)
205 * Hirokazu Takahashi : Use copy_from_user() instead of
206 * csum_and_copy_from_user() if possible.
207 *
208 * This program is free software; you can redistribute it and/or
209 * modify it under the terms of the GNU General Public License
210 * as published by the Free Software Foundation; either version
211 * 2 of the License, or(at your option) any later version.
212 *
213 * Description of States:
214 *
215 * TCP_SYN_SENT sent a connection request, waiting for ack
216 *
217 * TCP_SYN_RECV received a connection request, sent ack,
218 * waiting for final ack in three-way handshake.
219 *
220 * TCP_ESTABLISHED connection established
221 *
222 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
223 * transmission of remaining buffered data
224 *
225 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
226 * to shutdown
227 *
228 * TCP_CLOSING both sides have shutdown but we still have
229 * data we have to finish sending
230 *
231 * TCP_TIME_WAIT timeout to catch resent junk before entering
232 * closed, can only be entered from FIN_WAIT2
233 * or CLOSING. Required because the other end
234 * may not have gotten our last ACK causing it
235 * to retransmit the data packet (which we ignore)
236 *
237 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
238 * us to finish writing our data and to shutdown
239 * (we have to close() to move on to LAST_ACK)
240 *
241 * TCP_LAST_ACK out side has shutdown after remote has
242 * shutdown. There may still be data in our
243 * buffer that we have to finish sending
244 *
245 * TCP_CLOSE socket is finished
246 */
247
248 #include <linux/kernel.h>
249 #include <linux/module.h>
250 #include <linux/types.h>
251 #include <linux/fcntl.h>
252 #include <linux/poll.h>
253 #include <linux/init.h>
254 #include <linux/fs.h>
255 #include <linux/skbuff.h>
256 #include <linux/scatterlist.h>
257 #include <linux/splice.h>
258 #include <linux/net.h>
259 #include <linux/socket.h>
260 #include <linux/random.h>
261 #include <linux/bootmem.h>
262 #include <linux/highmem.h>
263 #include <linux/swap.h>
264 #include <linux/cache.h>
265 #include <linux/err.h>
266 #include <linux/crypto.h>
267 #include <linux/time.h>
268 #include <linux/slab.h>
269
270 #include <net/icmp.h>
271 #include <net/tcp.h>
272 #include <net/xfrm.h>
273 #include <net/ip.h>
274 #include <net/netdma.h>
275 #include <net/sock.h>
276
277 #include <asm/uaccess.h>
278 #include <asm/ioctls.h>
279
280 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
281
282 struct percpu_counter tcp_orphan_count;
283 EXPORT_SYMBOL_GPL(tcp_orphan_count);
284
285 int sysctl_tcp_wmem[3] __read_mostly;
286 int sysctl_tcp_rmem[3] __read_mostly;
287
288 EXPORT_SYMBOL(sysctl_tcp_rmem);
289 EXPORT_SYMBOL(sysctl_tcp_wmem);
290
291 atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
292 EXPORT_SYMBOL(tcp_memory_allocated);
293
294 /*
295 * Current number of TCP sockets.
296 */
297 struct percpu_counter tcp_sockets_allocated;
298 EXPORT_SYMBOL(tcp_sockets_allocated);
299
300 /*
301 * TCP splice context
302 */
303 struct tcp_splice_state {
304 struct pipe_inode_info *pipe;
305 size_t len;
306 unsigned int flags;
307 };
308
309 /*
310 * Pressure flag: try to collapse.
311 * Technical note: it is used by multiple contexts non atomically.
312 * All the __sk_mem_schedule() is of this nature: accounting
313 * is strict, actions are advisory and have some latency.
314 */
315 int tcp_memory_pressure __read_mostly;
316 EXPORT_SYMBOL(tcp_memory_pressure);
317
318 void tcp_enter_memory_pressure(struct sock *sk)
319 {
320 if (!tcp_memory_pressure) {
321 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
322 tcp_memory_pressure = 1;
323 }
324 }
325 EXPORT_SYMBOL(tcp_enter_memory_pressure);
326
327 /* Convert seconds to retransmits based on initial and max timeout */
328 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
329 {
330 u8 res = 0;
331
332 if (seconds > 0) {
333 int period = timeout;
334
335 res = 1;
336 while (seconds > period && res < 255) {
337 res++;
338 timeout <<= 1;
339 if (timeout > rto_max)
340 timeout = rto_max;
341 period += timeout;
342 }
343 }
344 return res;
345 }
346
347 /* Convert retransmits to seconds based on initial and max timeout */
348 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
349 {
350 int period = 0;
351
352 if (retrans > 0) {
353 period = timeout;
354 while (--retrans) {
355 timeout <<= 1;
356 if (timeout > rto_max)
357 timeout = rto_max;
358 period += timeout;
359 }
360 }
361 return period;
362 }
363
364 /*
365 * Wait for a TCP event.
366 *
367 * Note that we don't need to lock the socket, as the upper poll layers
368 * take care of normal races (between the test and the event) and we don't
369 * go look at any of the socket buffers directly.
370 */
371 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
372 {
373 unsigned int mask;
374 struct sock *sk = sock->sk;
375 const struct tcp_sock *tp = tcp_sk(sk);
376
377 sock_poll_wait(file, sk_sleep(sk), wait);
378 if (sk->sk_state == TCP_LISTEN)
379 return inet_csk_listen_poll(sk);
380
381 /* Socket is not locked. We are protected from async events
382 * by poll logic and correct handling of state changes
383 * made by other threads is impossible in any case.
384 */
385
386 mask = 0;
387
388 /*
389 * POLLHUP is certainly not done right. But poll() doesn't
390 * have a notion of HUP in just one direction, and for a
391 * socket the read side is more interesting.
392 *
393 * Some poll() documentation says that POLLHUP is incompatible
394 * with the POLLOUT/POLLWR flags, so somebody should check this
395 * all. But careful, it tends to be safer to return too many
396 * bits than too few, and you can easily break real applications
397 * if you don't tell them that something has hung up!
398 *
399 * Check-me.
400 *
401 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
402 * our fs/select.c). It means that after we received EOF,
403 * poll always returns immediately, making impossible poll() on write()
404 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
405 * if and only if shutdown has been made in both directions.
406 * Actually, it is interesting to look how Solaris and DUX
407 * solve this dilemma. I would prefer, if POLLHUP were maskable,
408 * then we could set it on SND_SHUTDOWN. BTW examples given
409 * in Stevens' books assume exactly this behaviour, it explains
410 * why POLLHUP is incompatible with POLLOUT. --ANK
411 *
412 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
413 * blocking on fresh not-connected or disconnected socket. --ANK
414 */
415 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
416 mask |= POLLHUP;
417 if (sk->sk_shutdown & RCV_SHUTDOWN)
418 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
419
420 /* Connected? */
421 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
422 int target = sock_rcvlowat(sk, 0, INT_MAX);
423
424 if (tp->urg_seq == tp->copied_seq &&
425 !sock_flag(sk, SOCK_URGINLINE) &&
426 tp->urg_data)
427 target++;
428
429 /* Potential race condition. If read of tp below will
430 * escape above sk->sk_state, we can be illegally awaken
431 * in SYN_* states. */
432 if (tp->rcv_nxt - tp->copied_seq >= target)
433 mask |= POLLIN | POLLRDNORM;
434
435 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
436 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
437 mask |= POLLOUT | POLLWRNORM;
438 } else { /* send SIGIO later */
439 set_bit(SOCK_ASYNC_NOSPACE,
440 &sk->sk_socket->flags);
441 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
442
443 /* Race breaker. If space is freed after
444 * wspace test but before the flags are set,
445 * IO signal will be lost.
446 */
447 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
448 mask |= POLLOUT | POLLWRNORM;
449 }
450 } else
451 mask |= POLLOUT | POLLWRNORM;
452
453 if (tp->urg_data & TCP_URG_VALID)
454 mask |= POLLPRI;
455 }
456 /* This barrier is coupled with smp_wmb() in tcp_reset() */
457 smp_rmb();
458 if (sk->sk_err)
459 mask |= POLLERR;
460
461 return mask;
462 }
463 EXPORT_SYMBOL(tcp_poll);
464
465 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
466 {
467 struct tcp_sock *tp = tcp_sk(sk);
468 int answ;
469
470 switch (cmd) {
471 case SIOCINQ:
472 if (sk->sk_state == TCP_LISTEN)
473 return -EINVAL;
474
475 lock_sock(sk);
476 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
477 answ = 0;
478 else if (sock_flag(sk, SOCK_URGINLINE) ||
479 !tp->urg_data ||
480 before(tp->urg_seq, tp->copied_seq) ||
481 !before(tp->urg_seq, tp->rcv_nxt)) {
482 struct sk_buff *skb;
483
484 answ = tp->rcv_nxt - tp->copied_seq;
485
486 /* Subtract 1, if FIN is in queue. */
487 skb = skb_peek_tail(&sk->sk_receive_queue);
488 if (answ && skb)
489 answ -= tcp_hdr(skb)->fin;
490 } else
491 answ = tp->urg_seq - tp->copied_seq;
492 release_sock(sk);
493 break;
494 case SIOCATMARK:
495 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
496 break;
497 case SIOCOUTQ:
498 if (sk->sk_state == TCP_LISTEN)
499 return -EINVAL;
500
501 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
502 answ = 0;
503 else
504 answ = tp->write_seq - tp->snd_una;
505 break;
506 case SIOCOUTQNSD:
507 if (sk->sk_state == TCP_LISTEN)
508 return -EINVAL;
509
510 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
511 answ = 0;
512 else
513 answ = tp->write_seq - tp->snd_nxt;
514 break;
515 default:
516 return -ENOIOCTLCMD;
517 }
518
519 return put_user(answ, (int __user *)arg);
520 }
521 EXPORT_SYMBOL(tcp_ioctl);
522
523 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
524 {
525 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
526 tp->pushed_seq = tp->write_seq;
527 }
528
529 static inline int forced_push(const struct tcp_sock *tp)
530 {
531 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
532 }
533
534 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
535 {
536 struct tcp_sock *tp = tcp_sk(sk);
537 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
538
539 skb->csum = 0;
540 tcb->seq = tcb->end_seq = tp->write_seq;
541 tcb->tcp_flags = TCPHDR_ACK;
542 tcb->sacked = 0;
543 skb_header_release(skb);
544 tcp_add_write_queue_tail(sk, skb);
545 sk->sk_wmem_queued += skb->truesize;
546 sk_mem_charge(sk, skb->truesize);
547 if (tp->nonagle & TCP_NAGLE_PUSH)
548 tp->nonagle &= ~TCP_NAGLE_PUSH;
549 }
550
551 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
552 {
553 if (flags & MSG_OOB)
554 tp->snd_up = tp->write_seq;
555 }
556
557 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
558 int nonagle)
559 {
560 if (tcp_send_head(sk)) {
561 struct tcp_sock *tp = tcp_sk(sk);
562
563 if (!(flags & MSG_MORE) || forced_push(tp))
564 tcp_mark_push(tp, tcp_write_queue_tail(sk));
565
566 tcp_mark_urg(tp, flags);
567 __tcp_push_pending_frames(sk, mss_now,
568 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
569 }
570 }
571
572 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
573 unsigned int offset, size_t len)
574 {
575 struct tcp_splice_state *tss = rd_desc->arg.data;
576 int ret;
577
578 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
579 tss->flags);
580 if (ret > 0)
581 rd_desc->count -= ret;
582 return ret;
583 }
584
585 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
586 {
587 /* Store TCP splice context information in read_descriptor_t. */
588 read_descriptor_t rd_desc = {
589 .arg.data = tss,
590 .count = tss->len,
591 };
592
593 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
594 }
595
596 /**
597 * tcp_splice_read - splice data from TCP socket to a pipe
598 * @sock: socket to splice from
599 * @ppos: position (not valid)
600 * @pipe: pipe to splice to
601 * @len: number of bytes to splice
602 * @flags: splice modifier flags
603 *
604 * Description:
605 * Will read pages from given socket and fill them into a pipe.
606 *
607 **/
608 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
609 struct pipe_inode_info *pipe, size_t len,
610 unsigned int flags)
611 {
612 struct sock *sk = sock->sk;
613 struct tcp_splice_state tss = {
614 .pipe = pipe,
615 .len = len,
616 .flags = flags,
617 };
618 long timeo;
619 ssize_t spliced;
620 int ret;
621
622 sock_rps_record_flow(sk);
623 /*
624 * We can't seek on a socket input
625 */
626 if (unlikely(*ppos))
627 return -ESPIPE;
628
629 ret = spliced = 0;
630
631 lock_sock(sk);
632
633 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
634 while (tss.len) {
635 ret = __tcp_splice_read(sk, &tss);
636 if (ret < 0)
637 break;
638 else if (!ret) {
639 if (spliced)
640 break;
641 if (sock_flag(sk, SOCK_DONE))
642 break;
643 if (sk->sk_err) {
644 ret = sock_error(sk);
645 break;
646 }
647 if (sk->sk_shutdown & RCV_SHUTDOWN)
648 break;
649 if (sk->sk_state == TCP_CLOSE) {
650 /*
651 * This occurs when user tries to read
652 * from never connected socket.
653 */
654 if (!sock_flag(sk, SOCK_DONE))
655 ret = -ENOTCONN;
656 break;
657 }
658 if (!timeo) {
659 ret = -EAGAIN;
660 break;
661 }
662 sk_wait_data(sk, &timeo);
663 if (signal_pending(current)) {
664 ret = sock_intr_errno(timeo);
665 break;
666 }
667 continue;
668 }
669 tss.len -= ret;
670 spliced += ret;
671
672 if (!timeo)
673 break;
674 release_sock(sk);
675 lock_sock(sk);
676
677 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
678 (sk->sk_shutdown & RCV_SHUTDOWN) ||
679 signal_pending(current))
680 break;
681 }
682
683 release_sock(sk);
684
685 if (spliced)
686 return spliced;
687
688 return ret;
689 }
690 EXPORT_SYMBOL(tcp_splice_read);
691
692 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
693 {
694 struct sk_buff *skb;
695
696 /* The TCP header must be at least 32-bit aligned. */
697 size = ALIGN(size, 4);
698
699 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
700 if (skb) {
701 if (sk_wmem_schedule(sk, skb->truesize)) {
702 /*
703 * Make sure that we have exactly size bytes
704 * available to the caller, no more, no less.
705 */
706 skb_reserve(skb, skb_tailroom(skb) - size);
707 return skb;
708 }
709 __kfree_skb(skb);
710 } else {
711 sk->sk_prot->enter_memory_pressure(sk);
712 sk_stream_moderate_sndbuf(sk);
713 }
714 return NULL;
715 }
716
717 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
718 int large_allowed)
719 {
720 struct tcp_sock *tp = tcp_sk(sk);
721 u32 xmit_size_goal, old_size_goal;
722
723 xmit_size_goal = mss_now;
724
725 if (large_allowed && sk_can_gso(sk)) {
726 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
727 inet_csk(sk)->icsk_af_ops->net_header_len -
728 inet_csk(sk)->icsk_ext_hdr_len -
729 tp->tcp_header_len);
730
731 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
732
733 /* We try hard to avoid divides here */
734 old_size_goal = tp->xmit_size_goal_segs * mss_now;
735
736 if (likely(old_size_goal <= xmit_size_goal &&
737 old_size_goal + mss_now > xmit_size_goal)) {
738 xmit_size_goal = old_size_goal;
739 } else {
740 tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
741 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
742 }
743 }
744
745 return max(xmit_size_goal, mss_now);
746 }
747
748 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
749 {
750 int mss_now;
751
752 mss_now = tcp_current_mss(sk);
753 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
754
755 return mss_now;
756 }
757
758 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
759 size_t psize, int flags)
760 {
761 struct tcp_sock *tp = tcp_sk(sk);
762 int mss_now, size_goal;
763 int err;
764 ssize_t copied;
765 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
766
767 /* Wait for a connection to finish. */
768 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
769 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
770 goto out_err;
771
772 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
773
774 mss_now = tcp_send_mss(sk, &size_goal, flags);
775 copied = 0;
776
777 err = -EPIPE;
778 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
779 goto out_err;
780
781 while (psize > 0) {
782 struct sk_buff *skb = tcp_write_queue_tail(sk);
783 struct page *page = pages[poffset / PAGE_SIZE];
784 int copy, i, can_coalesce;
785 int offset = poffset % PAGE_SIZE;
786 int size = min_t(size_t, psize, PAGE_SIZE - offset);
787
788 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
789 new_segment:
790 if (!sk_stream_memory_free(sk))
791 goto wait_for_sndbuf;
792
793 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
794 if (!skb)
795 goto wait_for_memory;
796
797 skb_entail(sk, skb);
798 copy = size_goal;
799 }
800
801 if (copy > size)
802 copy = size;
803
804 i = skb_shinfo(skb)->nr_frags;
805 can_coalesce = skb_can_coalesce(skb, i, page, offset);
806 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
807 tcp_mark_push(tp, skb);
808 goto new_segment;
809 }
810 if (!sk_wmem_schedule(sk, copy))
811 goto wait_for_memory;
812
813 if (can_coalesce) {
814 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
815 } else {
816 get_page(page);
817 skb_fill_page_desc(skb, i, page, offset, copy);
818 }
819
820 skb->len += copy;
821 skb->data_len += copy;
822 skb->truesize += copy;
823 sk->sk_wmem_queued += copy;
824 sk_mem_charge(sk, copy);
825 skb->ip_summed = CHECKSUM_PARTIAL;
826 tp->write_seq += copy;
827 TCP_SKB_CB(skb)->end_seq += copy;
828 skb_shinfo(skb)->gso_segs = 0;
829
830 if (!copied)
831 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
832
833 copied += copy;
834 poffset += copy;
835 if (!(psize -= copy))
836 goto out;
837
838 if (skb->len < size_goal || (flags & MSG_OOB))
839 continue;
840
841 if (forced_push(tp)) {
842 tcp_mark_push(tp, skb);
843 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
844 } else if (skb == tcp_send_head(sk))
845 tcp_push_one(sk, mss_now);
846 continue;
847
848 wait_for_sndbuf:
849 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
850 wait_for_memory:
851 if (copied)
852 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
853
854 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
855 goto do_error;
856
857 mss_now = tcp_send_mss(sk, &size_goal, flags);
858 }
859
860 out:
861 if (copied)
862 tcp_push(sk, flags, mss_now, tp->nonagle);
863 return copied;
864
865 do_error:
866 if (copied)
867 goto out;
868 out_err:
869 return sk_stream_error(sk, flags, err);
870 }
871
872 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
873 size_t size, int flags)
874 {
875 ssize_t res;
876
877 if (!(sk->sk_route_caps & NETIF_F_SG) ||
878 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
879 return sock_no_sendpage(sk->sk_socket, page, offset, size,
880 flags);
881
882 lock_sock(sk);
883 res = do_tcp_sendpages(sk, &page, offset, size, flags);
884 release_sock(sk);
885 return res;
886 }
887 EXPORT_SYMBOL(tcp_sendpage);
888
889 static inline int select_size(const struct sock *sk, bool sg)
890 {
891 const struct tcp_sock *tp = tcp_sk(sk);
892 int tmp = tp->mss_cache;
893
894 if (sg) {
895 if (sk_can_gso(sk)) {
896 /* Small frames wont use a full page:
897 * Payload will immediately follow tcp header.
898 */
899 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
900 } else {
901 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
902
903 if (tmp >= pgbreak &&
904 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
905 tmp = pgbreak;
906 }
907 }
908
909 return tmp;
910 }
911
912 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
913 size_t size)
914 {
915 struct iovec *iov;
916 struct tcp_sock *tp = tcp_sk(sk);
917 struct sk_buff *skb;
918 int iovlen, flags, err, copied;
919 int mss_now, size_goal;
920 bool sg;
921 long timeo;
922
923 lock_sock(sk);
924
925 flags = msg->msg_flags;
926 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
927
928 /* Wait for a connection to finish. */
929 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
930 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
931 goto out_err;
932
933 /* This should be in poll */
934 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
935
936 mss_now = tcp_send_mss(sk, &size_goal, flags);
937
938 /* Ok commence sending. */
939 iovlen = msg->msg_iovlen;
940 iov = msg->msg_iov;
941 copied = 0;
942
943 err = -EPIPE;
944 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
945 goto out_err;
946
947 sg = !!(sk->sk_route_caps & NETIF_F_SG);
948
949 while (--iovlen >= 0) {
950 size_t seglen = iov->iov_len;
951 unsigned char __user *from = iov->iov_base;
952
953 iov++;
954
955 while (seglen > 0) {
956 int copy = 0;
957 int max = size_goal;
958
959 skb = tcp_write_queue_tail(sk);
960 if (tcp_send_head(sk)) {
961 if (skb->ip_summed == CHECKSUM_NONE)
962 max = mss_now;
963 copy = max - skb->len;
964 }
965
966 if (copy <= 0) {
967 new_segment:
968 /* Allocate new segment. If the interface is SG,
969 * allocate skb fitting to single page.
970 */
971 if (!sk_stream_memory_free(sk))
972 goto wait_for_sndbuf;
973
974 skb = sk_stream_alloc_skb(sk,
975 select_size(sk, sg),
976 sk->sk_allocation);
977 if (!skb)
978 goto wait_for_memory;
979
980 /*
981 * Check whether we can use HW checksum.
982 */
983 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
984 skb->ip_summed = CHECKSUM_PARTIAL;
985
986 skb_entail(sk, skb);
987 copy = size_goal;
988 max = size_goal;
989 }
990
991 /* Try to append data to the end of skb. */
992 if (copy > seglen)
993 copy = seglen;
994
995 /* Where to copy to? */
996 if (skb_tailroom(skb) > 0) {
997 /* We have some space in skb head. Superb! */
998 if (copy > skb_tailroom(skb))
999 copy = skb_tailroom(skb);
1000 err = skb_add_data_nocache(sk, skb, from, copy);
1001 if (err)
1002 goto do_fault;
1003 } else {
1004 int merge = 0;
1005 int i = skb_shinfo(skb)->nr_frags;
1006 struct page *page = sk->sk_sndmsg_page;
1007 int off;
1008
1009 if (page && page_count(page) == 1)
1010 sk->sk_sndmsg_off = 0;
1011
1012 off = sk->sk_sndmsg_off;
1013
1014 if (skb_can_coalesce(skb, i, page, off) &&
1015 off != PAGE_SIZE) {
1016 /* We can extend the last page
1017 * fragment. */
1018 merge = 1;
1019 } else if (i == MAX_SKB_FRAGS || !sg) {
1020 /* Need to add new fragment and cannot
1021 * do this because interface is non-SG,
1022 * or because all the page slots are
1023 * busy. */
1024 tcp_mark_push(tp, skb);
1025 goto new_segment;
1026 } else if (page) {
1027 if (off == PAGE_SIZE) {
1028 put_page(page);
1029 sk->sk_sndmsg_page = page = NULL;
1030 off = 0;
1031 }
1032 } else
1033 off = 0;
1034
1035 if (copy > PAGE_SIZE - off)
1036 copy = PAGE_SIZE - off;
1037
1038 if (!sk_wmem_schedule(sk, copy))
1039 goto wait_for_memory;
1040
1041 if (!page) {
1042 /* Allocate new cache page. */
1043 if (!(page = sk_stream_alloc_page(sk)))
1044 goto wait_for_memory;
1045 }
1046
1047 /* Time to copy data. We are close to
1048 * the end! */
1049 err = skb_copy_to_page_nocache(sk, from, skb,
1050 page, off, copy);
1051 if (err) {
1052 /* If this page was new, give it to the
1053 * socket so it does not get leaked.
1054 */
1055 if (!sk->sk_sndmsg_page) {
1056 sk->sk_sndmsg_page = page;
1057 sk->sk_sndmsg_off = 0;
1058 }
1059 goto do_error;
1060 }
1061
1062 /* Update the skb. */
1063 if (merge) {
1064 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1065 } else {
1066 skb_fill_page_desc(skb, i, page, off, copy);
1067 if (sk->sk_sndmsg_page) {
1068 get_page(page);
1069 } else if (off + copy < PAGE_SIZE) {
1070 get_page(page);
1071 sk->sk_sndmsg_page = page;
1072 }
1073 }
1074
1075 sk->sk_sndmsg_off = off + copy;
1076 }
1077
1078 if (!copied)
1079 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1080
1081 tp->write_seq += copy;
1082 TCP_SKB_CB(skb)->end_seq += copy;
1083 skb_shinfo(skb)->gso_segs = 0;
1084
1085 from += copy;
1086 copied += copy;
1087 if ((seglen -= copy) == 0 && iovlen == 0)
1088 goto out;
1089
1090 if (skb->len < max || (flags & MSG_OOB))
1091 continue;
1092
1093 if (forced_push(tp)) {
1094 tcp_mark_push(tp, skb);
1095 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1096 } else if (skb == tcp_send_head(sk))
1097 tcp_push_one(sk, mss_now);
1098 continue;
1099
1100 wait_for_sndbuf:
1101 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1102 wait_for_memory:
1103 if (copied)
1104 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1105
1106 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1107 goto do_error;
1108
1109 mss_now = tcp_send_mss(sk, &size_goal, flags);
1110 }
1111 }
1112
1113 out:
1114 if (copied)
1115 tcp_push(sk, flags, mss_now, tp->nonagle);
1116 release_sock(sk);
1117 return copied;
1118
1119 do_fault:
1120 if (!skb->len) {
1121 tcp_unlink_write_queue(skb, sk);
1122 /* It is the one place in all of TCP, except connection
1123 * reset, where we can be unlinking the send_head.
1124 */
1125 tcp_check_send_head(sk, skb);
1126 sk_wmem_free_skb(sk, skb);
1127 }
1128
1129 do_error:
1130 if (copied)
1131 goto out;
1132 out_err:
1133 err = sk_stream_error(sk, flags, err);
1134 release_sock(sk);
1135 return err;
1136 }
1137 EXPORT_SYMBOL(tcp_sendmsg);
1138
1139 /*
1140 * Handle reading urgent data. BSD has very simple semantics for
1141 * this, no blocking and very strange errors 8)
1142 */
1143
1144 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1145 {
1146 struct tcp_sock *tp = tcp_sk(sk);
1147
1148 /* No URG data to read. */
1149 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1150 tp->urg_data == TCP_URG_READ)
1151 return -EINVAL; /* Yes this is right ! */
1152
1153 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1154 return -ENOTCONN;
1155
1156 if (tp->urg_data & TCP_URG_VALID) {
1157 int err = 0;
1158 char c = tp->urg_data;
1159
1160 if (!(flags & MSG_PEEK))
1161 tp->urg_data = TCP_URG_READ;
1162
1163 /* Read urgent data. */
1164 msg->msg_flags |= MSG_OOB;
1165
1166 if (len > 0) {
1167 if (!(flags & MSG_TRUNC))
1168 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1169 len = 1;
1170 } else
1171 msg->msg_flags |= MSG_TRUNC;
1172
1173 return err ? -EFAULT : len;
1174 }
1175
1176 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1177 return 0;
1178
1179 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1180 * the available implementations agree in this case:
1181 * this call should never block, independent of the
1182 * blocking state of the socket.
1183 * Mike <pall@rz.uni-karlsruhe.de>
1184 */
1185 return -EAGAIN;
1186 }
1187
1188 /* Clean up the receive buffer for full frames taken by the user,
1189 * then send an ACK if necessary. COPIED is the number of bytes
1190 * tcp_recvmsg has given to the user so far, it speeds up the
1191 * calculation of whether or not we must ACK for the sake of
1192 * a window update.
1193 */
1194 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1195 {
1196 struct tcp_sock *tp = tcp_sk(sk);
1197 int time_to_ack = 0;
1198
1199 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1200
1201 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1202 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1203 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1204
1205 if (inet_csk_ack_scheduled(sk)) {
1206 const struct inet_connection_sock *icsk = inet_csk(sk);
1207 /* Delayed ACKs frequently hit locked sockets during bulk
1208 * receive. */
1209 if (icsk->icsk_ack.blocked ||
1210 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1211 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1212 /*
1213 * If this read emptied read buffer, we send ACK, if
1214 * connection is not bidirectional, user drained
1215 * receive buffer and there was a small segment
1216 * in queue.
1217 */
1218 (copied > 0 &&
1219 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1220 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1221 !icsk->icsk_ack.pingpong)) &&
1222 !atomic_read(&sk->sk_rmem_alloc)))
1223 time_to_ack = 1;
1224 }
1225
1226 /* We send an ACK if we can now advertise a non-zero window
1227 * which has been raised "significantly".
1228 *
1229 * Even if window raised up to infinity, do not send window open ACK
1230 * in states, where we will not receive more. It is useless.
1231 */
1232 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1233 __u32 rcv_window_now = tcp_receive_window(tp);
1234
1235 /* Optimize, __tcp_select_window() is not cheap. */
1236 if (2*rcv_window_now <= tp->window_clamp) {
1237 __u32 new_window = __tcp_select_window(sk);
1238
1239 /* Send ACK now, if this read freed lots of space
1240 * in our buffer. Certainly, new_window is new window.
1241 * We can advertise it now, if it is not less than current one.
1242 * "Lots" means "at least twice" here.
1243 */
1244 if (new_window && new_window >= 2 * rcv_window_now)
1245 time_to_ack = 1;
1246 }
1247 }
1248 if (time_to_ack)
1249 tcp_send_ack(sk);
1250 }
1251
1252 static void tcp_prequeue_process(struct sock *sk)
1253 {
1254 struct sk_buff *skb;
1255 struct tcp_sock *tp = tcp_sk(sk);
1256
1257 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1258
1259 /* RX process wants to run with disabled BHs, though it is not
1260 * necessary */
1261 local_bh_disable();
1262 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1263 sk_backlog_rcv(sk, skb);
1264 local_bh_enable();
1265
1266 /* Clear memory counter. */
1267 tp->ucopy.memory = 0;
1268 }
1269
1270 #ifdef CONFIG_NET_DMA
1271 static void tcp_service_net_dma(struct sock *sk, bool wait)
1272 {
1273 dma_cookie_t done, used;
1274 dma_cookie_t last_issued;
1275 struct tcp_sock *tp = tcp_sk(sk);
1276
1277 if (!tp->ucopy.dma_chan)
1278 return;
1279
1280 last_issued = tp->ucopy.dma_cookie;
1281 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1282
1283 do {
1284 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1285 last_issued, &done,
1286 &used) == DMA_SUCCESS) {
1287 /* Safe to free early-copied skbs now */
1288 __skb_queue_purge(&sk->sk_async_wait_queue);
1289 break;
1290 } else {
1291 struct sk_buff *skb;
1292 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1293 (dma_async_is_complete(skb->dma_cookie, done,
1294 used) == DMA_SUCCESS)) {
1295 __skb_dequeue(&sk->sk_async_wait_queue);
1296 kfree_skb(skb);
1297 }
1298 }
1299 } while (wait);
1300 }
1301 #endif
1302
1303 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1304 {
1305 struct sk_buff *skb;
1306 u32 offset;
1307
1308 skb_queue_walk(&sk->sk_receive_queue, skb) {
1309 offset = seq - TCP_SKB_CB(skb)->seq;
1310 if (tcp_hdr(skb)->syn)
1311 offset--;
1312 if (offset < skb->len || tcp_hdr(skb)->fin) {
1313 *off = offset;
1314 return skb;
1315 }
1316 }
1317 return NULL;
1318 }
1319
1320 /*
1321 * This routine provides an alternative to tcp_recvmsg() for routines
1322 * that would like to handle copying from skbuffs directly in 'sendfile'
1323 * fashion.
1324 * Note:
1325 * - It is assumed that the socket was locked by the caller.
1326 * - The routine does not block.
1327 * - At present, there is no support for reading OOB data
1328 * or for 'peeking' the socket using this routine
1329 * (although both would be easy to implement).
1330 */
1331 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1332 sk_read_actor_t recv_actor)
1333 {
1334 struct sk_buff *skb;
1335 struct tcp_sock *tp = tcp_sk(sk);
1336 u32 seq = tp->copied_seq;
1337 u32 offset;
1338 int copied = 0;
1339
1340 if (sk->sk_state == TCP_LISTEN)
1341 return -ENOTCONN;
1342 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1343 if (offset < skb->len) {
1344 int used;
1345 size_t len;
1346
1347 len = skb->len - offset;
1348 /* Stop reading if we hit a patch of urgent data */
1349 if (tp->urg_data) {
1350 u32 urg_offset = tp->urg_seq - seq;
1351 if (urg_offset < len)
1352 len = urg_offset;
1353 if (!len)
1354 break;
1355 }
1356 used = recv_actor(desc, skb, offset, len);
1357 if (used < 0) {
1358 if (!copied)
1359 copied = used;
1360 break;
1361 } else if (used <= len) {
1362 seq += used;
1363 copied += used;
1364 offset += used;
1365 }
1366 /*
1367 * If recv_actor drops the lock (e.g. TCP splice
1368 * receive) the skb pointer might be invalid when
1369 * getting here: tcp_collapse might have deleted it
1370 * while aggregating skbs from the socket queue.
1371 */
1372 skb = tcp_recv_skb(sk, seq-1, &offset);
1373 if (!skb || (offset+1 != skb->len))
1374 break;
1375 }
1376 if (tcp_hdr(skb)->fin) {
1377 sk_eat_skb(sk, skb, 0);
1378 ++seq;
1379 break;
1380 }
1381 sk_eat_skb(sk, skb, 0);
1382 if (!desc->count)
1383 break;
1384 tp->copied_seq = seq;
1385 }
1386 tp->copied_seq = seq;
1387
1388 tcp_rcv_space_adjust(sk);
1389
1390 /* Clean up data we have read: This will do ACK frames. */
1391 if (copied > 0)
1392 tcp_cleanup_rbuf(sk, copied);
1393 return copied;
1394 }
1395 EXPORT_SYMBOL(tcp_read_sock);
1396
1397 /*
1398 * This routine copies from a sock struct into the user buffer.
1399 *
1400 * Technical note: in 2.3 we work on _locked_ socket, so that
1401 * tricks with *seq access order and skb->users are not required.
1402 * Probably, code can be easily improved even more.
1403 */
1404
1405 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1406 size_t len, int nonblock, int flags, int *addr_len)
1407 {
1408 struct tcp_sock *tp = tcp_sk(sk);
1409 int copied = 0;
1410 u32 peek_seq;
1411 u32 *seq;
1412 unsigned long used;
1413 int err;
1414 int target; /* Read at least this many bytes */
1415 long timeo;
1416 struct task_struct *user_recv = NULL;
1417 int copied_early = 0;
1418 struct sk_buff *skb;
1419 u32 urg_hole = 0;
1420
1421 lock_sock(sk);
1422
1423 err = -ENOTCONN;
1424 if (sk->sk_state == TCP_LISTEN)
1425 goto out;
1426
1427 timeo = sock_rcvtimeo(sk, nonblock);
1428
1429 /* Urgent data needs to be handled specially. */
1430 if (flags & MSG_OOB)
1431 goto recv_urg;
1432
1433 seq = &tp->copied_seq;
1434 if (flags & MSG_PEEK) {
1435 peek_seq = tp->copied_seq;
1436 seq = &peek_seq;
1437 }
1438
1439 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1440
1441 #ifdef CONFIG_NET_DMA
1442 tp->ucopy.dma_chan = NULL;
1443 preempt_disable();
1444 skb = skb_peek_tail(&sk->sk_receive_queue);
1445 {
1446 int available = 0;
1447
1448 if (skb)
1449 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1450 if ((available < target) &&
1451 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1452 !sysctl_tcp_low_latency &&
1453 dma_find_channel(DMA_MEMCPY)) {
1454 preempt_enable_no_resched();
1455 tp->ucopy.pinned_list =
1456 dma_pin_iovec_pages(msg->msg_iov, len);
1457 } else {
1458 preempt_enable_no_resched();
1459 }
1460 }
1461 #endif
1462
1463 do {
1464 u32 offset;
1465
1466 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1467 if (tp->urg_data && tp->urg_seq == *seq) {
1468 if (copied)
1469 break;
1470 if (signal_pending(current)) {
1471 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1472 break;
1473 }
1474 }
1475
1476 /* Next get a buffer. */
1477
1478 skb_queue_walk(&sk->sk_receive_queue, skb) {
1479 /* Now that we have two receive queues this
1480 * shouldn't happen.
1481 */
1482 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1483 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1484 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1485 flags))
1486 break;
1487
1488 offset = *seq - TCP_SKB_CB(skb)->seq;
1489 if (tcp_hdr(skb)->syn)
1490 offset--;
1491 if (offset < skb->len)
1492 goto found_ok_skb;
1493 if (tcp_hdr(skb)->fin)
1494 goto found_fin_ok;
1495 WARN(!(flags & MSG_PEEK),
1496 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1497 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1498 }
1499
1500 /* Well, if we have backlog, try to process it now yet. */
1501
1502 if (copied >= target && !sk->sk_backlog.tail)
1503 break;
1504
1505 if (copied) {
1506 if (sk->sk_err ||
1507 sk->sk_state == TCP_CLOSE ||
1508 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1509 !timeo ||
1510 signal_pending(current))
1511 break;
1512 } else {
1513 if (sock_flag(sk, SOCK_DONE))
1514 break;
1515
1516 if (sk->sk_err) {
1517 copied = sock_error(sk);
1518 break;
1519 }
1520
1521 if (sk->sk_shutdown & RCV_SHUTDOWN)
1522 break;
1523
1524 if (sk->sk_state == TCP_CLOSE) {
1525 if (!sock_flag(sk, SOCK_DONE)) {
1526 /* This occurs when user tries to read
1527 * from never connected socket.
1528 */
1529 copied = -ENOTCONN;
1530 break;
1531 }
1532 break;
1533 }
1534
1535 if (!timeo) {
1536 copied = -EAGAIN;
1537 break;
1538 }
1539
1540 if (signal_pending(current)) {
1541 copied = sock_intr_errno(timeo);
1542 break;
1543 }
1544 }
1545
1546 tcp_cleanup_rbuf(sk, copied);
1547
1548 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1549 /* Install new reader */
1550 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1551 user_recv = current;
1552 tp->ucopy.task = user_recv;
1553 tp->ucopy.iov = msg->msg_iov;
1554 }
1555
1556 tp->ucopy.len = len;
1557
1558 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1559 !(flags & (MSG_PEEK | MSG_TRUNC)));
1560
1561 /* Ugly... If prequeue is not empty, we have to
1562 * process it before releasing socket, otherwise
1563 * order will be broken at second iteration.
1564 * More elegant solution is required!!!
1565 *
1566 * Look: we have the following (pseudo)queues:
1567 *
1568 * 1. packets in flight
1569 * 2. backlog
1570 * 3. prequeue
1571 * 4. receive_queue
1572 *
1573 * Each queue can be processed only if the next ones
1574 * are empty. At this point we have empty receive_queue.
1575 * But prequeue _can_ be not empty after 2nd iteration,
1576 * when we jumped to start of loop because backlog
1577 * processing added something to receive_queue.
1578 * We cannot release_sock(), because backlog contains
1579 * packets arrived _after_ prequeued ones.
1580 *
1581 * Shortly, algorithm is clear --- to process all
1582 * the queues in order. We could make it more directly,
1583 * requeueing packets from backlog to prequeue, if
1584 * is not empty. It is more elegant, but eats cycles,
1585 * unfortunately.
1586 */
1587 if (!skb_queue_empty(&tp->ucopy.prequeue))
1588 goto do_prequeue;
1589
1590 /* __ Set realtime policy in scheduler __ */
1591 }
1592
1593 #ifdef CONFIG_NET_DMA
1594 if (tp->ucopy.dma_chan)
1595 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1596 #endif
1597 if (copied >= target) {
1598 /* Do not sleep, just process backlog. */
1599 release_sock(sk);
1600 lock_sock(sk);
1601 } else
1602 sk_wait_data(sk, &timeo);
1603
1604 #ifdef CONFIG_NET_DMA
1605 tcp_service_net_dma(sk, false); /* Don't block */
1606 tp->ucopy.wakeup = 0;
1607 #endif
1608
1609 if (user_recv) {
1610 int chunk;
1611
1612 /* __ Restore normal policy in scheduler __ */
1613
1614 if ((chunk = len - tp->ucopy.len) != 0) {
1615 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1616 len -= chunk;
1617 copied += chunk;
1618 }
1619
1620 if (tp->rcv_nxt == tp->copied_seq &&
1621 !skb_queue_empty(&tp->ucopy.prequeue)) {
1622 do_prequeue:
1623 tcp_prequeue_process(sk);
1624
1625 if ((chunk = len - tp->ucopy.len) != 0) {
1626 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1627 len -= chunk;
1628 copied += chunk;
1629 }
1630 }
1631 }
1632 if ((flags & MSG_PEEK) &&
1633 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1634 if (net_ratelimit())
1635 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1636 current->comm, task_pid_nr(current));
1637 peek_seq = tp->copied_seq;
1638 }
1639 continue;
1640
1641 found_ok_skb:
1642 /* Ok so how much can we use? */
1643 used = skb->len - offset;
1644 if (len < used)
1645 used = len;
1646
1647 /* Do we have urgent data here? */
1648 if (tp->urg_data) {
1649 u32 urg_offset = tp->urg_seq - *seq;
1650 if (urg_offset < used) {
1651 if (!urg_offset) {
1652 if (!sock_flag(sk, SOCK_URGINLINE)) {
1653 ++*seq;
1654 urg_hole++;
1655 offset++;
1656 used--;
1657 if (!used)
1658 goto skip_copy;
1659 }
1660 } else
1661 used = urg_offset;
1662 }
1663 }
1664
1665 if (!(flags & MSG_TRUNC)) {
1666 #ifdef CONFIG_NET_DMA
1667 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1668 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1669
1670 if (tp->ucopy.dma_chan) {
1671 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1672 tp->ucopy.dma_chan, skb, offset,
1673 msg->msg_iov, used,
1674 tp->ucopy.pinned_list);
1675
1676 if (tp->ucopy.dma_cookie < 0) {
1677
1678 printk(KERN_ALERT "dma_cookie < 0\n");
1679
1680 /* Exception. Bailout! */
1681 if (!copied)
1682 copied = -EFAULT;
1683 break;
1684 }
1685
1686 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1687
1688 if ((offset + used) == skb->len)
1689 copied_early = 1;
1690
1691 } else
1692 #endif
1693 {
1694 err = skb_copy_datagram_iovec(skb, offset,
1695 msg->msg_iov, used);
1696 if (err) {
1697 /* Exception. Bailout! */
1698 if (!copied)
1699 copied = -EFAULT;
1700 break;
1701 }
1702 }
1703 }
1704
1705 *seq += used;
1706 copied += used;
1707 len -= used;
1708
1709 tcp_rcv_space_adjust(sk);
1710
1711 skip_copy:
1712 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1713 tp->urg_data = 0;
1714 tcp_fast_path_check(sk);
1715 }
1716 if (used + offset < skb->len)
1717 continue;
1718
1719 if (tcp_hdr(skb)->fin)
1720 goto found_fin_ok;
1721 if (!(flags & MSG_PEEK)) {
1722 sk_eat_skb(sk, skb, copied_early);
1723 copied_early = 0;
1724 }
1725 continue;
1726
1727 found_fin_ok:
1728 /* Process the FIN. */
1729 ++*seq;
1730 if (!(flags & MSG_PEEK)) {
1731 sk_eat_skb(sk, skb, copied_early);
1732 copied_early = 0;
1733 }
1734 break;
1735 } while (len > 0);
1736
1737 if (user_recv) {
1738 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1739 int chunk;
1740
1741 tp->ucopy.len = copied > 0 ? len : 0;
1742
1743 tcp_prequeue_process(sk);
1744
1745 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1746 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1747 len -= chunk;
1748 copied += chunk;
1749 }
1750 }
1751
1752 tp->ucopy.task = NULL;
1753 tp->ucopy.len = 0;
1754 }
1755
1756 #ifdef CONFIG_NET_DMA
1757 tcp_service_net_dma(sk, true); /* Wait for queue to drain */
1758 tp->ucopy.dma_chan = NULL;
1759
1760 if (tp->ucopy.pinned_list) {
1761 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1762 tp->ucopy.pinned_list = NULL;
1763 }
1764 #endif
1765
1766 /* According to UNIX98, msg_name/msg_namelen are ignored
1767 * on connected socket. I was just happy when found this 8) --ANK
1768 */
1769
1770 /* Clean up data we have read: This will do ACK frames. */
1771 tcp_cleanup_rbuf(sk, copied);
1772
1773 release_sock(sk);
1774 return copied;
1775
1776 out:
1777 release_sock(sk);
1778 return err;
1779
1780 recv_urg:
1781 err = tcp_recv_urg(sk, msg, len, flags);
1782 goto out;
1783 }
1784 EXPORT_SYMBOL(tcp_recvmsg);
1785
1786 void tcp_set_state(struct sock *sk, int state)
1787 {
1788 int oldstate = sk->sk_state;
1789
1790 switch (state) {
1791 case TCP_ESTABLISHED:
1792 if (oldstate != TCP_ESTABLISHED)
1793 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1794 break;
1795
1796 case TCP_CLOSE:
1797 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1798 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1799
1800 sk->sk_prot->unhash(sk);
1801 if (inet_csk(sk)->icsk_bind_hash &&
1802 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1803 inet_put_port(sk);
1804 /* fall through */
1805 default:
1806 if (oldstate == TCP_ESTABLISHED)
1807 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1808 }
1809
1810 /* Change state AFTER socket is unhashed to avoid closed
1811 * socket sitting in hash tables.
1812 */
1813 sk->sk_state = state;
1814
1815 #ifdef STATE_TRACE
1816 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1817 #endif
1818 }
1819 EXPORT_SYMBOL_GPL(tcp_set_state);
1820
1821 /*
1822 * State processing on a close. This implements the state shift for
1823 * sending our FIN frame. Note that we only send a FIN for some
1824 * states. A shutdown() may have already sent the FIN, or we may be
1825 * closed.
1826 */
1827
1828 static const unsigned char new_state[16] = {
1829 /* current state: new state: action: */
1830 /* (Invalid) */ TCP_CLOSE,
1831 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1832 /* TCP_SYN_SENT */ TCP_CLOSE,
1833 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1834 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1835 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1836 /* TCP_TIME_WAIT */ TCP_CLOSE,
1837 /* TCP_CLOSE */ TCP_CLOSE,
1838 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1839 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1840 /* TCP_LISTEN */ TCP_CLOSE,
1841 /* TCP_CLOSING */ TCP_CLOSING,
1842 };
1843
1844 static int tcp_close_state(struct sock *sk)
1845 {
1846 int next = (int)new_state[sk->sk_state];
1847 int ns = next & TCP_STATE_MASK;
1848
1849 tcp_set_state(sk, ns);
1850
1851 return next & TCP_ACTION_FIN;
1852 }
1853
1854 /*
1855 * Shutdown the sending side of a connection. Much like close except
1856 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1857 */
1858
1859 void tcp_shutdown(struct sock *sk, int how)
1860 {
1861 /* We need to grab some memory, and put together a FIN,
1862 * and then put it into the queue to be sent.
1863 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1864 */
1865 if (!(how & SEND_SHUTDOWN))
1866 return;
1867
1868 /* If we've already sent a FIN, or it's a closed state, skip this. */
1869 if ((1 << sk->sk_state) &
1870 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1871 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1872 /* Clear out any half completed packets. FIN if needed. */
1873 if (tcp_close_state(sk))
1874 tcp_send_fin(sk);
1875 }
1876 }
1877 EXPORT_SYMBOL(tcp_shutdown);
1878
1879 bool tcp_check_oom(struct sock *sk, int shift)
1880 {
1881 bool too_many_orphans, out_of_socket_memory;
1882
1883 too_many_orphans = tcp_too_many_orphans(sk, shift);
1884 out_of_socket_memory = tcp_out_of_memory(sk);
1885
1886 if (too_many_orphans && net_ratelimit())
1887 pr_info("TCP: too many orphaned sockets\n");
1888 if (out_of_socket_memory && net_ratelimit())
1889 pr_info("TCP: out of memory -- consider tuning tcp_mem\n");
1890 return too_many_orphans || out_of_socket_memory;
1891 }
1892
1893 void tcp_close(struct sock *sk, long timeout)
1894 {
1895 struct sk_buff *skb;
1896 int data_was_unread = 0;
1897 int state;
1898
1899 lock_sock(sk);
1900 sk->sk_shutdown = SHUTDOWN_MASK;
1901
1902 if (sk->sk_state == TCP_LISTEN) {
1903 tcp_set_state(sk, TCP_CLOSE);
1904
1905 /* Special case. */
1906 inet_csk_listen_stop(sk);
1907
1908 goto adjudge_to_death;
1909 }
1910
1911 /* We need to flush the recv. buffs. We do this only on the
1912 * descriptor close, not protocol-sourced closes, because the
1913 * reader process may not have drained the data yet!
1914 */
1915 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1916 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1917 tcp_hdr(skb)->fin;
1918 data_was_unread += len;
1919 __kfree_skb(skb);
1920 }
1921
1922 sk_mem_reclaim(sk);
1923
1924 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
1925 if (sk->sk_state == TCP_CLOSE)
1926 goto adjudge_to_death;
1927
1928 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1929 * data was lost. To witness the awful effects of the old behavior of
1930 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1931 * GET in an FTP client, suspend the process, wait for the client to
1932 * advertise a zero window, then kill -9 the FTP client, wheee...
1933 * Note: timeout is always zero in such a case.
1934 */
1935 if (data_was_unread) {
1936 /* Unread data was tossed, zap the connection. */
1937 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1938 tcp_set_state(sk, TCP_CLOSE);
1939 tcp_send_active_reset(sk, sk->sk_allocation);
1940 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1941 /* Check zero linger _after_ checking for unread data. */
1942 sk->sk_prot->disconnect(sk, 0);
1943 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1944 } else if (tcp_close_state(sk)) {
1945 /* We FIN if the application ate all the data before
1946 * zapping the connection.
1947 */
1948
1949 /* RED-PEN. Formally speaking, we have broken TCP state
1950 * machine. State transitions:
1951 *
1952 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1953 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1954 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1955 *
1956 * are legal only when FIN has been sent (i.e. in window),
1957 * rather than queued out of window. Purists blame.
1958 *
1959 * F.e. "RFC state" is ESTABLISHED,
1960 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1961 *
1962 * The visible declinations are that sometimes
1963 * we enter time-wait state, when it is not required really
1964 * (harmless), do not send active resets, when they are
1965 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1966 * they look as CLOSING or LAST_ACK for Linux)
1967 * Probably, I missed some more holelets.
1968 * --ANK
1969 */
1970 tcp_send_fin(sk);
1971 }
1972
1973 sk_stream_wait_close(sk, timeout);
1974
1975 adjudge_to_death:
1976 state = sk->sk_state;
1977 sock_hold(sk);
1978 sock_orphan(sk);
1979
1980 /* It is the last release_sock in its life. It will remove backlog. */
1981 release_sock(sk);
1982
1983
1984 /* Now socket is owned by kernel and we acquire BH lock
1985 to finish close. No need to check for user refs.
1986 */
1987 local_bh_disable();
1988 bh_lock_sock(sk);
1989 WARN_ON(sock_owned_by_user(sk));
1990
1991 percpu_counter_inc(sk->sk_prot->orphan_count);
1992
1993 /* Have we already been destroyed by a softirq or backlog? */
1994 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1995 goto out;
1996
1997 /* This is a (useful) BSD violating of the RFC. There is a
1998 * problem with TCP as specified in that the other end could
1999 * keep a socket open forever with no application left this end.
2000 * We use a 3 minute timeout (about the same as BSD) then kill
2001 * our end. If they send after that then tough - BUT: long enough
2002 * that we won't make the old 4*rto = almost no time - whoops
2003 * reset mistake.
2004 *
2005 * Nope, it was not mistake. It is really desired behaviour
2006 * f.e. on http servers, when such sockets are useless, but
2007 * consume significant resources. Let's do it with special
2008 * linger2 option. --ANK
2009 */
2010
2011 if (sk->sk_state == TCP_FIN_WAIT2) {
2012 struct tcp_sock *tp = tcp_sk(sk);
2013 if (tp->linger2 < 0) {
2014 tcp_set_state(sk, TCP_CLOSE);
2015 tcp_send_active_reset(sk, GFP_ATOMIC);
2016 NET_INC_STATS_BH(sock_net(sk),
2017 LINUX_MIB_TCPABORTONLINGER);
2018 } else {
2019 const int tmo = tcp_fin_time(sk);
2020
2021 if (tmo > TCP_TIMEWAIT_LEN) {
2022 inet_csk_reset_keepalive_timer(sk,
2023 tmo - TCP_TIMEWAIT_LEN);
2024 } else {
2025 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2026 goto out;
2027 }
2028 }
2029 }
2030 if (sk->sk_state != TCP_CLOSE) {
2031 sk_mem_reclaim(sk);
2032 if (tcp_check_oom(sk, 0)) {
2033 tcp_set_state(sk, TCP_CLOSE);
2034 tcp_send_active_reset(sk, GFP_ATOMIC);
2035 NET_INC_STATS_BH(sock_net(sk),
2036 LINUX_MIB_TCPABORTONMEMORY);
2037 }
2038 }
2039
2040 if (sk->sk_state == TCP_CLOSE)
2041 inet_csk_destroy_sock(sk);
2042 /* Otherwise, socket is reprieved until protocol close. */
2043
2044 out:
2045 bh_unlock_sock(sk);
2046 local_bh_enable();
2047 sock_put(sk);
2048 }
2049 EXPORT_SYMBOL(tcp_close);
2050
2051 /* These states need RST on ABORT according to RFC793 */
2052
2053 static inline int tcp_need_reset(int state)
2054 {
2055 return (1 << state) &
2056 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2057 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2058 }
2059
2060 int tcp_disconnect(struct sock *sk, int flags)
2061 {
2062 struct inet_sock *inet = inet_sk(sk);
2063 struct inet_connection_sock *icsk = inet_csk(sk);
2064 struct tcp_sock *tp = tcp_sk(sk);
2065 int err = 0;
2066 int old_state = sk->sk_state;
2067
2068 if (old_state != TCP_CLOSE)
2069 tcp_set_state(sk, TCP_CLOSE);
2070
2071 /* ABORT function of RFC793 */
2072 if (old_state == TCP_LISTEN) {
2073 inet_csk_listen_stop(sk);
2074 } else if (tcp_need_reset(old_state) ||
2075 (tp->snd_nxt != tp->write_seq &&
2076 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2077 /* The last check adjusts for discrepancy of Linux wrt. RFC
2078 * states
2079 */
2080 tcp_send_active_reset(sk, gfp_any());
2081 sk->sk_err = ECONNRESET;
2082 } else if (old_state == TCP_SYN_SENT)
2083 sk->sk_err = ECONNRESET;
2084
2085 tcp_clear_xmit_timers(sk);
2086 __skb_queue_purge(&sk->sk_receive_queue);
2087 tcp_write_queue_purge(sk);
2088 __skb_queue_purge(&tp->out_of_order_queue);
2089 #ifdef CONFIG_NET_DMA
2090 __skb_queue_purge(&sk->sk_async_wait_queue);
2091 #endif
2092
2093 inet->inet_dport = 0;
2094
2095 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2096 inet_reset_saddr(sk);
2097
2098 sk->sk_shutdown = 0;
2099 sock_reset_flag(sk, SOCK_DONE);
2100 tp->srtt = 0;
2101 if ((tp->write_seq += tp->max_window + 2) == 0)
2102 tp->write_seq = 1;
2103 icsk->icsk_backoff = 0;
2104 tp->snd_cwnd = 2;
2105 icsk->icsk_probes_out = 0;
2106 tp->packets_out = 0;
2107 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2108 tp->snd_cwnd_cnt = 0;
2109 tp->bytes_acked = 0;
2110 tp->window_clamp = 0;
2111 tcp_set_ca_state(sk, TCP_CA_Open);
2112 tcp_clear_retrans(tp);
2113 inet_csk_delack_init(sk);
2114 tcp_init_send_head(sk);
2115 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2116 __sk_dst_reset(sk);
2117
2118 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2119
2120 sk->sk_error_report(sk);
2121 return err;
2122 }
2123 EXPORT_SYMBOL(tcp_disconnect);
2124
2125 /*
2126 * Socket option code for TCP.
2127 */
2128 static int do_tcp_setsockopt(struct sock *sk, int level,
2129 int optname, char __user *optval, unsigned int optlen)
2130 {
2131 struct tcp_sock *tp = tcp_sk(sk);
2132 struct inet_connection_sock *icsk = inet_csk(sk);
2133 int val;
2134 int err = 0;
2135
2136 /* These are data/string values, all the others are ints */
2137 switch (optname) {
2138 case TCP_CONGESTION: {
2139 char name[TCP_CA_NAME_MAX];
2140
2141 if (optlen < 1)
2142 return -EINVAL;
2143
2144 val = strncpy_from_user(name, optval,
2145 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2146 if (val < 0)
2147 return -EFAULT;
2148 name[val] = 0;
2149
2150 lock_sock(sk);
2151 err = tcp_set_congestion_control(sk, name);
2152 release_sock(sk);
2153 return err;
2154 }
2155 case TCP_COOKIE_TRANSACTIONS: {
2156 struct tcp_cookie_transactions ctd;
2157 struct tcp_cookie_values *cvp = NULL;
2158
2159 if (sizeof(ctd) > optlen)
2160 return -EINVAL;
2161 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2162 return -EFAULT;
2163
2164 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2165 ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2166 return -EINVAL;
2167
2168 if (ctd.tcpct_cookie_desired == 0) {
2169 /* default to global value */
2170 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2171 ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2172 ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2173 return -EINVAL;
2174 }
2175
2176 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2177 /* Supercedes all other values */
2178 lock_sock(sk);
2179 if (tp->cookie_values != NULL) {
2180 kref_put(&tp->cookie_values->kref,
2181 tcp_cookie_values_release);
2182 tp->cookie_values = NULL;
2183 }
2184 tp->rx_opt.cookie_in_always = 0; /* false */
2185 tp->rx_opt.cookie_out_never = 1; /* true */
2186 release_sock(sk);
2187 return err;
2188 }
2189
2190 /* Allocate ancillary memory before locking.
2191 */
2192 if (ctd.tcpct_used > 0 ||
2193 (tp->cookie_values == NULL &&
2194 (sysctl_tcp_cookie_size > 0 ||
2195 ctd.tcpct_cookie_desired > 0 ||
2196 ctd.tcpct_s_data_desired > 0))) {
2197 cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2198 GFP_KERNEL);
2199 if (cvp == NULL)
2200 return -ENOMEM;
2201
2202 kref_init(&cvp->kref);
2203 }
2204 lock_sock(sk);
2205 tp->rx_opt.cookie_in_always =
2206 (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2207 tp->rx_opt.cookie_out_never = 0; /* false */
2208
2209 if (tp->cookie_values != NULL) {
2210 if (cvp != NULL) {
2211 /* Changed values are recorded by a changed
2212 * pointer, ensuring the cookie will differ,
2213 * without separately hashing each value later.
2214 */
2215 kref_put(&tp->cookie_values->kref,
2216 tcp_cookie_values_release);
2217 } else {
2218 cvp = tp->cookie_values;
2219 }
2220 }
2221
2222 if (cvp != NULL) {
2223 cvp->cookie_desired = ctd.tcpct_cookie_desired;
2224
2225 if (ctd.tcpct_used > 0) {
2226 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2227 ctd.tcpct_used);
2228 cvp->s_data_desired = ctd.tcpct_used;
2229 cvp->s_data_constant = 1; /* true */
2230 } else {
2231 /* No constant payload data. */
2232 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2233 cvp->s_data_constant = 0; /* false */
2234 }
2235
2236 tp->cookie_values = cvp;
2237 }
2238 release_sock(sk);
2239 return err;
2240 }
2241 default:
2242 /* fallthru */
2243 break;
2244 }
2245
2246 if (optlen < sizeof(int))
2247 return -EINVAL;
2248
2249 if (get_user(val, (int __user *)optval))
2250 return -EFAULT;
2251
2252 lock_sock(sk);
2253
2254 switch (optname) {
2255 case TCP_MAXSEG:
2256 /* Values greater than interface MTU won't take effect. However
2257 * at the point when this call is done we typically don't yet
2258 * know which interface is going to be used */
2259 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2260 err = -EINVAL;
2261 break;
2262 }
2263 tp->rx_opt.user_mss = val;
2264 break;
2265
2266 case TCP_NODELAY:
2267 if (val) {
2268 /* TCP_NODELAY is weaker than TCP_CORK, so that
2269 * this option on corked socket is remembered, but
2270 * it is not activated until cork is cleared.
2271 *
2272 * However, when TCP_NODELAY is set we make
2273 * an explicit push, which overrides even TCP_CORK
2274 * for currently queued segments.
2275 */
2276 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2277 tcp_push_pending_frames(sk);
2278 } else {
2279 tp->nonagle &= ~TCP_NAGLE_OFF;
2280 }
2281 break;
2282
2283 case TCP_THIN_LINEAR_TIMEOUTS:
2284 if (val < 0 || val > 1)
2285 err = -EINVAL;
2286 else
2287 tp->thin_lto = val;
2288 break;
2289
2290 case TCP_THIN_DUPACK:
2291 if (val < 0 || val > 1)
2292 err = -EINVAL;
2293 else
2294 tp->thin_dupack = val;
2295 break;
2296
2297 case TCP_CORK:
2298 /* When set indicates to always queue non-full frames.
2299 * Later the user clears this option and we transmit
2300 * any pending partial frames in the queue. This is
2301 * meant to be used alongside sendfile() to get properly
2302 * filled frames when the user (for example) must write
2303 * out headers with a write() call first and then use
2304 * sendfile to send out the data parts.
2305 *
2306 * TCP_CORK can be set together with TCP_NODELAY and it is
2307 * stronger than TCP_NODELAY.
2308 */
2309 if (val) {
2310 tp->nonagle |= TCP_NAGLE_CORK;
2311 } else {
2312 tp->nonagle &= ~TCP_NAGLE_CORK;
2313 if (tp->nonagle&TCP_NAGLE_OFF)
2314 tp->nonagle |= TCP_NAGLE_PUSH;
2315 tcp_push_pending_frames(sk);
2316 }
2317 break;
2318
2319 case TCP_KEEPIDLE:
2320 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2321 err = -EINVAL;
2322 else {
2323 tp->keepalive_time = val * HZ;
2324 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2325 !((1 << sk->sk_state) &
2326 (TCPF_CLOSE | TCPF_LISTEN))) {
2327 u32 elapsed = keepalive_time_elapsed(tp);
2328 if (tp->keepalive_time > elapsed)
2329 elapsed = tp->keepalive_time - elapsed;
2330 else
2331 elapsed = 0;
2332 inet_csk_reset_keepalive_timer(sk, elapsed);
2333 }
2334 }
2335 break;
2336 case TCP_KEEPINTVL:
2337 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2338 err = -EINVAL;
2339 else
2340 tp->keepalive_intvl = val * HZ;
2341 break;
2342 case TCP_KEEPCNT:
2343 if (val < 1 || val > MAX_TCP_KEEPCNT)
2344 err = -EINVAL;
2345 else
2346 tp->keepalive_probes = val;
2347 break;
2348 case TCP_SYNCNT:
2349 if (val < 1 || val > MAX_TCP_SYNCNT)
2350 err = -EINVAL;
2351 else
2352 icsk->icsk_syn_retries = val;
2353 break;
2354
2355 case TCP_LINGER2:
2356 if (val < 0)
2357 tp->linger2 = -1;
2358 else if (val > sysctl_tcp_fin_timeout / HZ)
2359 tp->linger2 = 0;
2360 else
2361 tp->linger2 = val * HZ;
2362 break;
2363
2364 case TCP_DEFER_ACCEPT:
2365 /* Translate value in seconds to number of retransmits */
2366 icsk->icsk_accept_queue.rskq_defer_accept =
2367 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2368 TCP_RTO_MAX / HZ);
2369 break;
2370
2371 case TCP_WINDOW_CLAMP:
2372 if (!val) {
2373 if (sk->sk_state != TCP_CLOSE) {
2374 err = -EINVAL;
2375 break;
2376 }
2377 tp->window_clamp = 0;
2378 } else
2379 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2380 SOCK_MIN_RCVBUF / 2 : val;
2381 break;
2382
2383 case TCP_QUICKACK:
2384 if (!val) {
2385 icsk->icsk_ack.pingpong = 1;
2386 } else {
2387 icsk->icsk_ack.pingpong = 0;
2388 if ((1 << sk->sk_state) &
2389 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2390 inet_csk_ack_scheduled(sk)) {
2391 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2392 tcp_cleanup_rbuf(sk, 1);
2393 if (!(val & 1))
2394 icsk->icsk_ack.pingpong = 1;
2395 }
2396 }
2397 break;
2398
2399 #ifdef CONFIG_TCP_MD5SIG
2400 case TCP_MD5SIG:
2401 /* Read the IP->Key mappings from userspace */
2402 err = tp->af_specific->md5_parse(sk, optval, optlen);
2403 break;
2404 #endif
2405 case TCP_USER_TIMEOUT:
2406 /* Cap the max timeout in ms TCP will retry/retrans
2407 * before giving up and aborting (ETIMEDOUT) a connection.
2408 */
2409 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2410 break;
2411 default:
2412 err = -ENOPROTOOPT;
2413 break;
2414 }
2415
2416 release_sock(sk);
2417 return err;
2418 }
2419
2420 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2421 unsigned int optlen)
2422 {
2423 const struct inet_connection_sock *icsk = inet_csk(sk);
2424
2425 if (level != SOL_TCP)
2426 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2427 optval, optlen);
2428 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2429 }
2430 EXPORT_SYMBOL(tcp_setsockopt);
2431
2432 #ifdef CONFIG_COMPAT
2433 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2434 char __user *optval, unsigned int optlen)
2435 {
2436 if (level != SOL_TCP)
2437 return inet_csk_compat_setsockopt(sk, level, optname,
2438 optval, optlen);
2439 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2440 }
2441 EXPORT_SYMBOL(compat_tcp_setsockopt);
2442 #endif
2443
2444 /* Return information about state of tcp endpoint in API format. */
2445 void tcp_get_info(const struct sock *sk, struct tcp_info *info)
2446 {
2447 const struct tcp_sock *tp = tcp_sk(sk);
2448 const struct inet_connection_sock *icsk = inet_csk(sk);
2449 u32 now = tcp_time_stamp;
2450
2451 memset(info, 0, sizeof(*info));
2452
2453 info->tcpi_state = sk->sk_state;
2454 info->tcpi_ca_state = icsk->icsk_ca_state;
2455 info->tcpi_retransmits = icsk->icsk_retransmits;
2456 info->tcpi_probes = icsk->icsk_probes_out;
2457 info->tcpi_backoff = icsk->icsk_backoff;
2458
2459 if (tp->rx_opt.tstamp_ok)
2460 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2461 if (tcp_is_sack(tp))
2462 info->tcpi_options |= TCPI_OPT_SACK;
2463 if (tp->rx_opt.wscale_ok) {
2464 info->tcpi_options |= TCPI_OPT_WSCALE;
2465 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2466 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2467 }
2468
2469 if (tp->ecn_flags & TCP_ECN_OK)
2470 info->tcpi_options |= TCPI_OPT_ECN;
2471 if (tp->ecn_flags & TCP_ECN_SEEN)
2472 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2473
2474 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2475 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2476 info->tcpi_snd_mss = tp->mss_cache;
2477 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2478
2479 if (sk->sk_state == TCP_LISTEN) {
2480 info->tcpi_unacked = sk->sk_ack_backlog;
2481 info->tcpi_sacked = sk->sk_max_ack_backlog;
2482 } else {
2483 info->tcpi_unacked = tp->packets_out;
2484 info->tcpi_sacked = tp->sacked_out;
2485 }
2486 info->tcpi_lost = tp->lost_out;
2487 info->tcpi_retrans = tp->retrans_out;
2488 info->tcpi_fackets = tp->fackets_out;
2489
2490 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2491 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2492 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2493
2494 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2495 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2496 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2497 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2498 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2499 info->tcpi_snd_cwnd = tp->snd_cwnd;
2500 info->tcpi_advmss = tp->advmss;
2501 info->tcpi_reordering = tp->reordering;
2502
2503 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2504 info->tcpi_rcv_space = tp->rcvq_space.space;
2505
2506 info->tcpi_total_retrans = tp->total_retrans;
2507 }
2508 EXPORT_SYMBOL_GPL(tcp_get_info);
2509
2510 static int do_tcp_getsockopt(struct sock *sk, int level,
2511 int optname, char __user *optval, int __user *optlen)
2512 {
2513 struct inet_connection_sock *icsk = inet_csk(sk);
2514 struct tcp_sock *tp = tcp_sk(sk);
2515 int val, len;
2516
2517 if (get_user(len, optlen))
2518 return -EFAULT;
2519
2520 len = min_t(unsigned int, len, sizeof(int));
2521
2522 if (len < 0)
2523 return -EINVAL;
2524
2525 switch (optname) {
2526 case TCP_MAXSEG:
2527 val = tp->mss_cache;
2528 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2529 val = tp->rx_opt.user_mss;
2530 break;
2531 case TCP_NODELAY:
2532 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2533 break;
2534 case TCP_CORK:
2535 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2536 break;
2537 case TCP_KEEPIDLE:
2538 val = keepalive_time_when(tp) / HZ;
2539 break;
2540 case TCP_KEEPINTVL:
2541 val = keepalive_intvl_when(tp) / HZ;
2542 break;
2543 case TCP_KEEPCNT:
2544 val = keepalive_probes(tp);
2545 break;
2546 case TCP_SYNCNT:
2547 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2548 break;
2549 case TCP_LINGER2:
2550 val = tp->linger2;
2551 if (val >= 0)
2552 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2553 break;
2554 case TCP_DEFER_ACCEPT:
2555 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2556 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2557 break;
2558 case TCP_WINDOW_CLAMP:
2559 val = tp->window_clamp;
2560 break;
2561 case TCP_INFO: {
2562 struct tcp_info info;
2563
2564 if (get_user(len, optlen))
2565 return -EFAULT;
2566
2567 tcp_get_info(sk, &info);
2568
2569 len = min_t(unsigned int, len, sizeof(info));
2570 if (put_user(len, optlen))
2571 return -EFAULT;
2572 if (copy_to_user(optval, &info, len))
2573 return -EFAULT;
2574 return 0;
2575 }
2576 case TCP_QUICKACK:
2577 val = !icsk->icsk_ack.pingpong;
2578 break;
2579
2580 case TCP_CONGESTION:
2581 if (get_user(len, optlen))
2582 return -EFAULT;
2583 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2584 if (put_user(len, optlen))
2585 return -EFAULT;
2586 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2587 return -EFAULT;
2588 return 0;
2589
2590 case TCP_COOKIE_TRANSACTIONS: {
2591 struct tcp_cookie_transactions ctd;
2592 struct tcp_cookie_values *cvp = tp->cookie_values;
2593
2594 if (get_user(len, optlen))
2595 return -EFAULT;
2596 if (len < sizeof(ctd))
2597 return -EINVAL;
2598
2599 memset(&ctd, 0, sizeof(ctd));
2600 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2601 TCP_COOKIE_IN_ALWAYS : 0)
2602 | (tp->rx_opt.cookie_out_never ?
2603 TCP_COOKIE_OUT_NEVER : 0);
2604
2605 if (cvp != NULL) {
2606 ctd.tcpct_flags |= (cvp->s_data_in ?
2607 TCP_S_DATA_IN : 0)
2608 | (cvp->s_data_out ?
2609 TCP_S_DATA_OUT : 0);
2610
2611 ctd.tcpct_cookie_desired = cvp->cookie_desired;
2612 ctd.tcpct_s_data_desired = cvp->s_data_desired;
2613
2614 memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2615 cvp->cookie_pair_size);
2616 ctd.tcpct_used = cvp->cookie_pair_size;
2617 }
2618
2619 if (put_user(sizeof(ctd), optlen))
2620 return -EFAULT;
2621 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2622 return -EFAULT;
2623 return 0;
2624 }
2625 case TCP_THIN_LINEAR_TIMEOUTS:
2626 val = tp->thin_lto;
2627 break;
2628 case TCP_THIN_DUPACK:
2629 val = tp->thin_dupack;
2630 break;
2631
2632 case TCP_USER_TIMEOUT:
2633 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2634 break;
2635 default:
2636 return -ENOPROTOOPT;
2637 }
2638
2639 if (put_user(len, optlen))
2640 return -EFAULT;
2641 if (copy_to_user(optval, &val, len))
2642 return -EFAULT;
2643 return 0;
2644 }
2645
2646 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2647 int __user *optlen)
2648 {
2649 struct inet_connection_sock *icsk = inet_csk(sk);
2650
2651 if (level != SOL_TCP)
2652 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2653 optval, optlen);
2654 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2655 }
2656 EXPORT_SYMBOL(tcp_getsockopt);
2657
2658 #ifdef CONFIG_COMPAT
2659 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2660 char __user *optval, int __user *optlen)
2661 {
2662 if (level != SOL_TCP)
2663 return inet_csk_compat_getsockopt(sk, level, optname,
2664 optval, optlen);
2665 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2666 }
2667 EXPORT_SYMBOL(compat_tcp_getsockopt);
2668 #endif
2669
2670 struct sk_buff *tcp_tso_segment(struct sk_buff *skb,
2671 netdev_features_t features)
2672 {
2673 struct sk_buff *segs = ERR_PTR(-EINVAL);
2674 struct tcphdr *th;
2675 unsigned thlen;
2676 unsigned int seq;
2677 __be32 delta;
2678 unsigned int oldlen;
2679 unsigned int mss;
2680
2681 if (!pskb_may_pull(skb, sizeof(*th)))
2682 goto out;
2683
2684 th = tcp_hdr(skb);
2685 thlen = th->doff * 4;
2686 if (thlen < sizeof(*th))
2687 goto out;
2688
2689 if (!pskb_may_pull(skb, thlen))
2690 goto out;
2691
2692 oldlen = (u16)~skb->len;
2693 __skb_pull(skb, thlen);
2694
2695 mss = skb_shinfo(skb)->gso_size;
2696 if (unlikely(skb->len <= mss))
2697 goto out;
2698
2699 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2700 /* Packet is from an untrusted source, reset gso_segs. */
2701 int type = skb_shinfo(skb)->gso_type;
2702
2703 if (unlikely(type &
2704 ~(SKB_GSO_TCPV4 |
2705 SKB_GSO_DODGY |
2706 SKB_GSO_TCP_ECN |
2707 SKB_GSO_TCPV6 |
2708 0) ||
2709 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2710 goto out;
2711
2712 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2713
2714 segs = NULL;
2715 goto out;
2716 }
2717
2718 segs = skb_segment(skb, features);
2719 if (IS_ERR(segs))
2720 goto out;
2721
2722 delta = htonl(oldlen + (thlen + mss));
2723
2724 skb = segs;
2725 th = tcp_hdr(skb);
2726 seq = ntohl(th->seq);
2727
2728 do {
2729 th->fin = th->psh = 0;
2730
2731 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2732 (__force u32)delta));
2733 if (skb->ip_summed != CHECKSUM_PARTIAL)
2734 th->check =
2735 csum_fold(csum_partial(skb_transport_header(skb),
2736 thlen, skb->csum));
2737
2738 seq += mss;
2739 skb = skb->next;
2740 th = tcp_hdr(skb);
2741
2742 th->seq = htonl(seq);
2743 th->cwr = 0;
2744 } while (skb->next);
2745
2746 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2747 skb->data_len);
2748 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2749 (__force u32)delta));
2750 if (skb->ip_summed != CHECKSUM_PARTIAL)
2751 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2752 thlen, skb->csum));
2753
2754 out:
2755 return segs;
2756 }
2757 EXPORT_SYMBOL(tcp_tso_segment);
2758
2759 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2760 {
2761 struct sk_buff **pp = NULL;
2762 struct sk_buff *p;
2763 struct tcphdr *th;
2764 struct tcphdr *th2;
2765 unsigned int len;
2766 unsigned int thlen;
2767 __be32 flags;
2768 unsigned int mss = 1;
2769 unsigned int hlen;
2770 unsigned int off;
2771 int flush = 1;
2772 int i;
2773
2774 off = skb_gro_offset(skb);
2775 hlen = off + sizeof(*th);
2776 th = skb_gro_header_fast(skb, off);
2777 if (skb_gro_header_hard(skb, hlen)) {
2778 th = skb_gro_header_slow(skb, hlen, off);
2779 if (unlikely(!th))
2780 goto out;
2781 }
2782
2783 thlen = th->doff * 4;
2784 if (thlen < sizeof(*th))
2785 goto out;
2786
2787 hlen = off + thlen;
2788 if (skb_gro_header_hard(skb, hlen)) {
2789 th = skb_gro_header_slow(skb, hlen, off);
2790 if (unlikely(!th))
2791 goto out;
2792 }
2793
2794 skb_gro_pull(skb, thlen);
2795
2796 len = skb_gro_len(skb);
2797 flags = tcp_flag_word(th);
2798
2799 for (; (p = *head); head = &p->next) {
2800 if (!NAPI_GRO_CB(p)->same_flow)
2801 continue;
2802
2803 th2 = tcp_hdr(p);
2804
2805 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2806 NAPI_GRO_CB(p)->same_flow = 0;
2807 continue;
2808 }
2809
2810 goto found;
2811 }
2812
2813 goto out_check_final;
2814
2815 found:
2816 flush = NAPI_GRO_CB(p)->flush;
2817 flush |= (__force int)(flags & TCP_FLAG_CWR);
2818 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
2819 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
2820 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
2821 for (i = sizeof(*th); i < thlen; i += 4)
2822 flush |= *(u32 *)((u8 *)th + i) ^
2823 *(u32 *)((u8 *)th2 + i);
2824
2825 mss = skb_shinfo(p)->gso_size;
2826
2827 flush |= (len - 1) >= mss;
2828 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2829
2830 if (flush || skb_gro_receive(head, skb)) {
2831 mss = 1;
2832 goto out_check_final;
2833 }
2834
2835 p = *head;
2836 th2 = tcp_hdr(p);
2837 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2838
2839 out_check_final:
2840 flush = len < mss;
2841 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
2842 TCP_FLAG_RST | TCP_FLAG_SYN |
2843 TCP_FLAG_FIN));
2844
2845 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2846 pp = head;
2847
2848 out:
2849 NAPI_GRO_CB(skb)->flush |= flush;
2850
2851 return pp;
2852 }
2853 EXPORT_SYMBOL(tcp_gro_receive);
2854
2855 int tcp_gro_complete(struct sk_buff *skb)
2856 {
2857 struct tcphdr *th = tcp_hdr(skb);
2858
2859 skb->csum_start = skb_transport_header(skb) - skb->head;
2860 skb->csum_offset = offsetof(struct tcphdr, check);
2861 skb->ip_summed = CHECKSUM_PARTIAL;
2862
2863 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2864
2865 if (th->cwr)
2866 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2867
2868 return 0;
2869 }
2870 EXPORT_SYMBOL(tcp_gro_complete);
2871
2872 #ifdef CONFIG_TCP_MD5SIG
2873 static unsigned long tcp_md5sig_users;
2874 static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool;
2875 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2876
2877 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool)
2878 {
2879 int cpu;
2880
2881 for_each_possible_cpu(cpu) {
2882 struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu);
2883
2884 if (p->md5_desc.tfm)
2885 crypto_free_hash(p->md5_desc.tfm);
2886 }
2887 free_percpu(pool);
2888 }
2889
2890 void tcp_free_md5sig_pool(void)
2891 {
2892 struct tcp_md5sig_pool __percpu *pool = NULL;
2893
2894 spin_lock_bh(&tcp_md5sig_pool_lock);
2895 if (--tcp_md5sig_users == 0) {
2896 pool = tcp_md5sig_pool;
2897 tcp_md5sig_pool = NULL;
2898 }
2899 spin_unlock_bh(&tcp_md5sig_pool_lock);
2900 if (pool)
2901 __tcp_free_md5sig_pool(pool);
2902 }
2903 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2904
2905 static struct tcp_md5sig_pool __percpu *
2906 __tcp_alloc_md5sig_pool(struct sock *sk)
2907 {
2908 int cpu;
2909 struct tcp_md5sig_pool __percpu *pool;
2910
2911 pool = alloc_percpu(struct tcp_md5sig_pool);
2912 if (!pool)
2913 return NULL;
2914
2915 for_each_possible_cpu(cpu) {
2916 struct crypto_hash *hash;
2917
2918 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2919 if (!hash || IS_ERR(hash))
2920 goto out_free;
2921
2922 per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash;
2923 }
2924 return pool;
2925 out_free:
2926 __tcp_free_md5sig_pool(pool);
2927 return NULL;
2928 }
2929
2930 struct tcp_md5sig_pool __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
2931 {
2932 struct tcp_md5sig_pool __percpu *pool;
2933 int alloc = 0;
2934
2935 retry:
2936 spin_lock_bh(&tcp_md5sig_pool_lock);
2937 pool = tcp_md5sig_pool;
2938 if (tcp_md5sig_users++ == 0) {
2939 alloc = 1;
2940 spin_unlock_bh(&tcp_md5sig_pool_lock);
2941 } else if (!pool) {
2942 tcp_md5sig_users--;
2943 spin_unlock_bh(&tcp_md5sig_pool_lock);
2944 cpu_relax();
2945 goto retry;
2946 } else
2947 spin_unlock_bh(&tcp_md5sig_pool_lock);
2948
2949 if (alloc) {
2950 /* we cannot hold spinlock here because this may sleep. */
2951 struct tcp_md5sig_pool __percpu *p;
2952
2953 p = __tcp_alloc_md5sig_pool(sk);
2954 spin_lock_bh(&tcp_md5sig_pool_lock);
2955 if (!p) {
2956 tcp_md5sig_users--;
2957 spin_unlock_bh(&tcp_md5sig_pool_lock);
2958 return NULL;
2959 }
2960 pool = tcp_md5sig_pool;
2961 if (pool) {
2962 /* oops, it has already been assigned. */
2963 spin_unlock_bh(&tcp_md5sig_pool_lock);
2964 __tcp_free_md5sig_pool(p);
2965 } else {
2966 tcp_md5sig_pool = pool = p;
2967 spin_unlock_bh(&tcp_md5sig_pool_lock);
2968 }
2969 }
2970 return pool;
2971 }
2972 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2973
2974
2975 /**
2976 * tcp_get_md5sig_pool - get md5sig_pool for this user
2977 *
2978 * We use percpu structure, so if we succeed, we exit with preemption
2979 * and BH disabled, to make sure another thread or softirq handling
2980 * wont try to get same context.
2981 */
2982 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2983 {
2984 struct tcp_md5sig_pool __percpu *p;
2985
2986 local_bh_disable();
2987
2988 spin_lock(&tcp_md5sig_pool_lock);
2989 p = tcp_md5sig_pool;
2990 if (p)
2991 tcp_md5sig_users++;
2992 spin_unlock(&tcp_md5sig_pool_lock);
2993
2994 if (p)
2995 return this_cpu_ptr(p);
2996
2997 local_bh_enable();
2998 return NULL;
2999 }
3000 EXPORT_SYMBOL(tcp_get_md5sig_pool);
3001
3002 void tcp_put_md5sig_pool(void)
3003 {
3004 local_bh_enable();
3005 tcp_free_md5sig_pool();
3006 }
3007 EXPORT_SYMBOL(tcp_put_md5sig_pool);
3008
3009 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3010 const struct tcphdr *th)
3011 {
3012 struct scatterlist sg;
3013 struct tcphdr hdr;
3014 int err;
3015
3016 /* We are not allowed to change tcphdr, make a local copy */
3017 memcpy(&hdr, th, sizeof(hdr));
3018 hdr.check = 0;
3019
3020 /* options aren't included in the hash */
3021 sg_init_one(&sg, &hdr, sizeof(hdr));
3022 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
3023 return err;
3024 }
3025 EXPORT_SYMBOL(tcp_md5_hash_header);
3026
3027 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3028 const struct sk_buff *skb, unsigned int header_len)
3029 {
3030 struct scatterlist sg;
3031 const struct tcphdr *tp = tcp_hdr(skb);
3032 struct hash_desc *desc = &hp->md5_desc;
3033 unsigned i;
3034 const unsigned head_data_len = skb_headlen(skb) > header_len ?
3035 skb_headlen(skb) - header_len : 0;
3036 const struct skb_shared_info *shi = skb_shinfo(skb);
3037 struct sk_buff *frag_iter;
3038
3039 sg_init_table(&sg, 1);
3040
3041 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3042 if (crypto_hash_update(desc, &sg, head_data_len))
3043 return 1;
3044
3045 for (i = 0; i < shi->nr_frags; ++i) {
3046 const struct skb_frag_struct *f = &shi->frags[i];
3047 struct page *page = skb_frag_page(f);
3048 sg_set_page(&sg, page, skb_frag_size(f), f->page_offset);
3049 if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3050 return 1;
3051 }
3052
3053 skb_walk_frags(skb, frag_iter)
3054 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3055 return 1;
3056
3057 return 0;
3058 }
3059 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3060
3061 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3062 {
3063 struct scatterlist sg;
3064
3065 sg_init_one(&sg, key->key, key->keylen);
3066 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3067 }
3068 EXPORT_SYMBOL(tcp_md5_hash_key);
3069
3070 #endif
3071
3072 /**
3073 * Each Responder maintains up to two secret values concurrently for
3074 * efficient secret rollover. Each secret value has 4 states:
3075 *
3076 * Generating. (tcp_secret_generating != tcp_secret_primary)
3077 * Generates new Responder-Cookies, but not yet used for primary
3078 * verification. This is a short-term state, typically lasting only
3079 * one round trip time (RTT).
3080 *
3081 * Primary. (tcp_secret_generating == tcp_secret_primary)
3082 * Used both for generation and primary verification.
3083 *
3084 * Retiring. (tcp_secret_retiring != tcp_secret_secondary)
3085 * Used for verification, until the first failure that can be
3086 * verified by the newer Generating secret. At that time, this
3087 * cookie's state is changed to Secondary, and the Generating
3088 * cookie's state is changed to Primary. This is a short-term state,
3089 * typically lasting only one round trip time (RTT).
3090 *
3091 * Secondary. (tcp_secret_retiring == tcp_secret_secondary)
3092 * Used for secondary verification, after primary verification
3093 * failures. This state lasts no more than twice the Maximum Segment
3094 * Lifetime (2MSL). Then, the secret is discarded.
3095 */
3096 struct tcp_cookie_secret {
3097 /* The secret is divided into two parts. The digest part is the
3098 * equivalent of previously hashing a secret and saving the state,
3099 * and serves as an initialization vector (IV). The message part
3100 * serves as the trailing secret.
3101 */
3102 u32 secrets[COOKIE_WORKSPACE_WORDS];
3103 unsigned long expires;
3104 };
3105
3106 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3107 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3108 #define TCP_SECRET_LIFE (HZ * 600)
3109
3110 static struct tcp_cookie_secret tcp_secret_one;
3111 static struct tcp_cookie_secret tcp_secret_two;
3112
3113 /* Essentially a circular list, without dynamic allocation. */
3114 static struct tcp_cookie_secret *tcp_secret_generating;
3115 static struct tcp_cookie_secret *tcp_secret_primary;
3116 static struct tcp_cookie_secret *tcp_secret_retiring;
3117 static struct tcp_cookie_secret *tcp_secret_secondary;
3118
3119 static DEFINE_SPINLOCK(tcp_secret_locker);
3120
3121 /* Select a pseudo-random word in the cookie workspace.
3122 */
3123 static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3124 {
3125 return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3126 }
3127
3128 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3129 * Called in softirq context.
3130 * Returns: 0 for success.
3131 */
3132 int tcp_cookie_generator(u32 *bakery)
3133 {
3134 unsigned long jiffy = jiffies;
3135
3136 if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3137 spin_lock_bh(&tcp_secret_locker);
3138 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3139 /* refreshed by another */
3140 memcpy(bakery,
3141 &tcp_secret_generating->secrets[0],
3142 COOKIE_WORKSPACE_WORDS);
3143 } else {
3144 /* still needs refreshing */
3145 get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3146
3147 /* The first time, paranoia assumes that the
3148 * randomization function isn't as strong. But,
3149 * this secret initialization is delayed until
3150 * the last possible moment (packet arrival).
3151 * Although that time is observable, it is
3152 * unpredictably variable. Mash in the most
3153 * volatile clock bits available, and expire the
3154 * secret extra quickly.
3155 */
3156 if (unlikely(tcp_secret_primary->expires ==
3157 tcp_secret_secondary->expires)) {
3158 struct timespec tv;
3159
3160 getnstimeofday(&tv);
3161 bakery[COOKIE_DIGEST_WORDS+0] ^=
3162 (u32)tv.tv_nsec;
3163
3164 tcp_secret_secondary->expires = jiffy
3165 + TCP_SECRET_1MSL
3166 + (0x0f & tcp_cookie_work(bakery, 0));
3167 } else {
3168 tcp_secret_secondary->expires = jiffy
3169 + TCP_SECRET_LIFE
3170 + (0xff & tcp_cookie_work(bakery, 1));
3171 tcp_secret_primary->expires = jiffy
3172 + TCP_SECRET_2MSL
3173 + (0x1f & tcp_cookie_work(bakery, 2));
3174 }
3175 memcpy(&tcp_secret_secondary->secrets[0],
3176 bakery, COOKIE_WORKSPACE_WORDS);
3177
3178 rcu_assign_pointer(tcp_secret_generating,
3179 tcp_secret_secondary);
3180 rcu_assign_pointer(tcp_secret_retiring,
3181 tcp_secret_primary);
3182 /*
3183 * Neither call_rcu() nor synchronize_rcu() needed.
3184 * Retiring data is not freed. It is replaced after
3185 * further (locked) pointer updates, and a quiet time
3186 * (minimum 1MSL, maximum LIFE - 2MSL).
3187 */
3188 }
3189 spin_unlock_bh(&tcp_secret_locker);
3190 } else {
3191 rcu_read_lock_bh();
3192 memcpy(bakery,
3193 &rcu_dereference(tcp_secret_generating)->secrets[0],
3194 COOKIE_WORKSPACE_WORDS);
3195 rcu_read_unlock_bh();
3196 }
3197 return 0;
3198 }
3199 EXPORT_SYMBOL(tcp_cookie_generator);
3200
3201 void tcp_done(struct sock *sk)
3202 {
3203 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3204 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3205
3206 tcp_set_state(sk, TCP_CLOSE);
3207 tcp_clear_xmit_timers(sk);
3208
3209 sk->sk_shutdown = SHUTDOWN_MASK;
3210
3211 if (!sock_flag(sk, SOCK_DEAD))
3212 sk->sk_state_change(sk);
3213 else
3214 inet_csk_destroy_sock(sk);
3215 }
3216 EXPORT_SYMBOL_GPL(tcp_done);
3217
3218 extern struct tcp_congestion_ops tcp_reno;
3219
3220 static __initdata unsigned long thash_entries;
3221 static int __init set_thash_entries(char *str)
3222 {
3223 if (!str)
3224 return 0;
3225 thash_entries = simple_strtoul(str, &str, 0);
3226 return 1;
3227 }
3228 __setup("thash_entries=", set_thash_entries);
3229
3230 void tcp_init_mem(struct net *net)
3231 {
3232 unsigned long limit = nr_free_buffer_pages() / 8;
3233 limit = max(limit, 128UL);
3234 net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3;
3235 net->ipv4.sysctl_tcp_mem[1] = limit;
3236 net->ipv4.sysctl_tcp_mem[2] = net->ipv4.sysctl_tcp_mem[0] * 2;
3237 }
3238
3239 void __init tcp_init(void)
3240 {
3241 struct sk_buff *skb = NULL;
3242 unsigned long limit;
3243 int max_share, cnt;
3244 unsigned int i;
3245 unsigned long jiffy = jiffies;
3246
3247 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3248
3249 percpu_counter_init(&tcp_sockets_allocated, 0);
3250 percpu_counter_init(&tcp_orphan_count, 0);
3251 tcp_hashinfo.bind_bucket_cachep =
3252 kmem_cache_create("tcp_bind_bucket",
3253 sizeof(struct inet_bind_bucket), 0,
3254 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3255
3256 /* Size and allocate the main established and bind bucket
3257 * hash tables.
3258 *
3259 * The methodology is similar to that of the buffer cache.
3260 */
3261 tcp_hashinfo.ehash =
3262 alloc_large_system_hash("TCP established",
3263 sizeof(struct inet_ehash_bucket),
3264 thash_entries,
3265 (totalram_pages >= 128 * 1024) ?
3266 13 : 15,
3267 0,
3268 NULL,
3269 &tcp_hashinfo.ehash_mask,
3270 thash_entries ? 0 : 512 * 1024);
3271 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3272 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3273 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3274 }
3275 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3276 panic("TCP: failed to alloc ehash_locks");
3277 tcp_hashinfo.bhash =
3278 alloc_large_system_hash("TCP bind",
3279 sizeof(struct inet_bind_hashbucket),
3280 tcp_hashinfo.ehash_mask + 1,
3281 (totalram_pages >= 128 * 1024) ?
3282 13 : 15,
3283 0,
3284 &tcp_hashinfo.bhash_size,
3285 NULL,
3286 64 * 1024);
3287 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3288 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3289 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3290 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3291 }
3292
3293
3294 cnt = tcp_hashinfo.ehash_mask + 1;
3295
3296 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3297 sysctl_tcp_max_orphans = cnt / 2;
3298 sysctl_max_syn_backlog = max(128, cnt / 256);
3299
3300 tcp_init_mem(&init_net);
3301 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3302 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 10);
3303 limit = max(limit, 128UL);
3304 max_share = min(4UL*1024*1024, limit);
3305
3306 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3307 sysctl_tcp_wmem[1] = 16*1024;
3308 sysctl_tcp_wmem[2] = max(64*1024, max_share);
3309
3310 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3311 sysctl_tcp_rmem[1] = 87380;
3312 sysctl_tcp_rmem[2] = max(87380, max_share);
3313
3314 printk(KERN_INFO "TCP: Hash tables configured "
3315 "(established %u bind %u)\n",
3316 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3317
3318 tcp_register_congestion_control(&tcp_reno);
3319
3320 memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3321 memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3322 tcp_secret_one.expires = jiffy; /* past due */
3323 tcp_secret_two.expires = jiffy; /* past due */
3324 tcp_secret_generating = &tcp_secret_one;
3325 tcp_secret_primary = &tcp_secret_one;
3326 tcp_secret_retiring = &tcp_secret_two;
3327 tcp_secret_secondary = &tcp_secret_two;
3328 }
Linux with added FPC-III support