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Merge branch 'vhost-net' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[deliverable/linux.git] / net / ipv4 / tcp.c
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * 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_mem[3] __read_mostly;
286 int sysctl_tcp_wmem[3] __read_mostly;
287 int sysctl_tcp_rmem[3] __read_mostly;
288
289 EXPORT_SYMBOL(sysctl_tcp_mem);
290 EXPORT_SYMBOL(sysctl_tcp_rmem);
291 EXPORT_SYMBOL(sysctl_tcp_wmem);
292
293 atomic_t tcp_memory_allocated; /* Current allocated memory. */
294 EXPORT_SYMBOL(tcp_memory_allocated);
295
296 /*
297 * Current number of TCP sockets.
298 */
299 struct percpu_counter tcp_sockets_allocated;
300 EXPORT_SYMBOL(tcp_sockets_allocated);
301
302 /*
303 * TCP splice context
304 */
305 struct tcp_splice_state {
306 struct pipe_inode_info *pipe;
307 size_t len;
308 unsigned int flags;
309 };
310
311 /*
312 * Pressure flag: try to collapse.
313 * Technical note: it is used by multiple contexts non atomically.
314 * All the __sk_mem_schedule() is of this nature: accounting
315 * is strict, actions are advisory and have some latency.
316 */
317 int tcp_memory_pressure __read_mostly;
318
319 EXPORT_SYMBOL(tcp_memory_pressure);
320
321 void tcp_enter_memory_pressure(struct sock *sk)
322 {
323 if (!tcp_memory_pressure) {
324 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
325 tcp_memory_pressure = 1;
326 }
327 }
328
329 EXPORT_SYMBOL(tcp_enter_memory_pressure);
330
331 /* Convert seconds to retransmits based on initial and max timeout */
332 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
333 {
334 u8 res = 0;
335
336 if (seconds > 0) {
337 int period = timeout;
338
339 res = 1;
340 while (seconds > period && res < 255) {
341 res++;
342 timeout <<= 1;
343 if (timeout > rto_max)
344 timeout = rto_max;
345 period += timeout;
346 }
347 }
348 return res;
349 }
350
351 /* Convert retransmits to seconds based on initial and max timeout */
352 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
353 {
354 int period = 0;
355
356 if (retrans > 0) {
357 period = timeout;
358 while (--retrans) {
359 timeout <<= 1;
360 if (timeout > rto_max)
361 timeout = rto_max;
362 period += timeout;
363 }
364 }
365 return period;
366 }
367
368 /*
369 * Wait for a TCP event.
370 *
371 * Note that we don't need to lock the socket, as the upper poll layers
372 * take care of normal races (between the test and the event) and we don't
373 * go look at any of the socket buffers directly.
374 */
375 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
376 {
377 unsigned int mask;
378 struct sock *sk = sock->sk;
379 struct tcp_sock *tp = tcp_sk(sk);
380
381 sock_poll_wait(file, sk_sleep(sk), wait);
382 if (sk->sk_state == TCP_LISTEN)
383 return inet_csk_listen_poll(sk);
384
385 /* Socket is not locked. We are protected from async events
386 * by poll logic and correct handling of state changes
387 * made by other threads is impossible in any case.
388 */
389
390 mask = 0;
391 if (sk->sk_err)
392 mask = POLLERR;
393
394 /*
395 * POLLHUP is certainly not done right. But poll() doesn't
396 * have a notion of HUP in just one direction, and for a
397 * socket the read side is more interesting.
398 *
399 * Some poll() documentation says that POLLHUP is incompatible
400 * with the POLLOUT/POLLWR flags, so somebody should check this
401 * all. But careful, it tends to be safer to return too many
402 * bits than too few, and you can easily break real applications
403 * if you don't tell them that something has hung up!
404 *
405 * Check-me.
406 *
407 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
408 * our fs/select.c). It means that after we received EOF,
409 * poll always returns immediately, making impossible poll() on write()
410 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
411 * if and only if shutdown has been made in both directions.
412 * Actually, it is interesting to look how Solaris and DUX
413 * solve this dilemma. I would prefer, if POLLHUP were maskable,
414 * then we could set it on SND_SHUTDOWN. BTW examples given
415 * in Stevens' books assume exactly this behaviour, it explains
416 * why POLLHUP is incompatible with POLLOUT. --ANK
417 *
418 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
419 * blocking on fresh not-connected or disconnected socket. --ANK
420 */
421 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
422 mask |= POLLHUP;
423 if (sk->sk_shutdown & RCV_SHUTDOWN)
424 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
425
426 /* Connected? */
427 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
428 int target = sock_rcvlowat(sk, 0, INT_MAX);
429
430 if (tp->urg_seq == tp->copied_seq &&
431 !sock_flag(sk, SOCK_URGINLINE) &&
432 tp->urg_data)
433 target++;
434
435 /* Potential race condition. If read of tp below will
436 * escape above sk->sk_state, we can be illegally awaken
437 * in SYN_* states. */
438 if (tp->rcv_nxt - tp->copied_seq >= target)
439 mask |= POLLIN | POLLRDNORM;
440
441 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
442 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
443 mask |= POLLOUT | POLLWRNORM;
444 } else { /* send SIGIO later */
445 set_bit(SOCK_ASYNC_NOSPACE,
446 &sk->sk_socket->flags);
447 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
448
449 /* Race breaker. If space is freed after
450 * wspace test but before the flags are set,
451 * IO signal will be lost.
452 */
453 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
454 mask |= POLLOUT | POLLWRNORM;
455 }
456 }
457
458 if (tp->urg_data & TCP_URG_VALID)
459 mask |= POLLPRI;
460 }
461 return mask;
462 }
463
464 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
465 {
466 struct tcp_sock *tp = tcp_sk(sk);
467 int answ;
468
469 switch (cmd) {
470 case SIOCINQ:
471 if (sk->sk_state == TCP_LISTEN)
472 return -EINVAL;
473
474 lock_sock(sk);
475 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
476 answ = 0;
477 else if (sock_flag(sk, SOCK_URGINLINE) ||
478 !tp->urg_data ||
479 before(tp->urg_seq, tp->copied_seq) ||
480 !before(tp->urg_seq, tp->rcv_nxt)) {
481 struct sk_buff *skb;
482
483 answ = tp->rcv_nxt - tp->copied_seq;
484
485 /* Subtract 1, if FIN is in queue. */
486 skb = skb_peek_tail(&sk->sk_receive_queue);
487 if (answ && skb)
488 answ -= tcp_hdr(skb)->fin;
489 } else
490 answ = tp->urg_seq - tp->copied_seq;
491 release_sock(sk);
492 break;
493 case SIOCATMARK:
494 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
495 break;
496 case SIOCOUTQ:
497 if (sk->sk_state == TCP_LISTEN)
498 return -EINVAL;
499
500 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
501 answ = 0;
502 else
503 answ = tp->write_seq - tp->snd_una;
504 break;
505 default:
506 return -ENOIOCTLCMD;
507 }
508
509 return put_user(answ, (int __user *)arg);
510 }
511
512 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
513 {
514 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
515 tp->pushed_seq = tp->write_seq;
516 }
517
518 static inline int forced_push(struct tcp_sock *tp)
519 {
520 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
521 }
522
523 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
524 {
525 struct tcp_sock *tp = tcp_sk(sk);
526 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
527
528 skb->csum = 0;
529 tcb->seq = tcb->end_seq = tp->write_seq;
530 tcb->flags = TCPCB_FLAG_ACK;
531 tcb->sacked = 0;
532 skb_header_release(skb);
533 tcp_add_write_queue_tail(sk, skb);
534 sk->sk_wmem_queued += skb->truesize;
535 sk_mem_charge(sk, skb->truesize);
536 if (tp->nonagle & TCP_NAGLE_PUSH)
537 tp->nonagle &= ~TCP_NAGLE_PUSH;
538 }
539
540 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
541 {
542 if (flags & MSG_OOB)
543 tp->snd_up = tp->write_seq;
544 }
545
546 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
547 int nonagle)
548 {
549 if (tcp_send_head(sk)) {
550 struct tcp_sock *tp = tcp_sk(sk);
551
552 if (!(flags & MSG_MORE) || forced_push(tp))
553 tcp_mark_push(tp, tcp_write_queue_tail(sk));
554
555 tcp_mark_urg(tp, flags);
556 __tcp_push_pending_frames(sk, mss_now,
557 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
558 }
559 }
560
561 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
562 unsigned int offset, size_t len)
563 {
564 struct tcp_splice_state *tss = rd_desc->arg.data;
565 int ret;
566
567 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
568 tss->flags);
569 if (ret > 0)
570 rd_desc->count -= ret;
571 return ret;
572 }
573
574 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
575 {
576 /* Store TCP splice context information in read_descriptor_t. */
577 read_descriptor_t rd_desc = {
578 .arg.data = tss,
579 .count = tss->len,
580 };
581
582 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
583 }
584
585 /**
586 * tcp_splice_read - splice data from TCP socket to a pipe
587 * @sock: socket to splice from
588 * @ppos: position (not valid)
589 * @pipe: pipe to splice to
590 * @len: number of bytes to splice
591 * @flags: splice modifier flags
592 *
593 * Description:
594 * Will read pages from given socket and fill them into a pipe.
595 *
596 **/
597 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
598 struct pipe_inode_info *pipe, size_t len,
599 unsigned int flags)
600 {
601 struct sock *sk = sock->sk;
602 struct tcp_splice_state tss = {
603 .pipe = pipe,
604 .len = len,
605 .flags = flags,
606 };
607 long timeo;
608 ssize_t spliced;
609 int ret;
610
611 sock_rps_record_flow(sk);
612 /*
613 * We can't seek on a socket input
614 */
615 if (unlikely(*ppos))
616 return -ESPIPE;
617
618 ret = spliced = 0;
619
620 lock_sock(sk);
621
622 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
623 while (tss.len) {
624 ret = __tcp_splice_read(sk, &tss);
625 if (ret < 0)
626 break;
627 else if (!ret) {
628 if (spliced)
629 break;
630 if (sock_flag(sk, SOCK_DONE))
631 break;
632 if (sk->sk_err) {
633 ret = sock_error(sk);
634 break;
635 }
636 if (sk->sk_shutdown & RCV_SHUTDOWN)
637 break;
638 if (sk->sk_state == TCP_CLOSE) {
639 /*
640 * This occurs when user tries to read
641 * from never connected socket.
642 */
643 if (!sock_flag(sk, SOCK_DONE))
644 ret = -ENOTCONN;
645 break;
646 }
647 if (!timeo) {
648 ret = -EAGAIN;
649 break;
650 }
651 sk_wait_data(sk, &timeo);
652 if (signal_pending(current)) {
653 ret = sock_intr_errno(timeo);
654 break;
655 }
656 continue;
657 }
658 tss.len -= ret;
659 spliced += ret;
660
661 if (!timeo)
662 break;
663 release_sock(sk);
664 lock_sock(sk);
665
666 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
667 (sk->sk_shutdown & RCV_SHUTDOWN) ||
668 signal_pending(current))
669 break;
670 }
671
672 release_sock(sk);
673
674 if (spliced)
675 return spliced;
676
677 return ret;
678 }
679
680 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
681 {
682 struct sk_buff *skb;
683
684 /* The TCP header must be at least 32-bit aligned. */
685 size = ALIGN(size, 4);
686
687 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
688 if (skb) {
689 if (sk_wmem_schedule(sk, skb->truesize)) {
690 /*
691 * Make sure that we have exactly size bytes
692 * available to the caller, no more, no less.
693 */
694 skb_reserve(skb, skb_tailroom(skb) - size);
695 return skb;
696 }
697 __kfree_skb(skb);
698 } else {
699 sk->sk_prot->enter_memory_pressure(sk);
700 sk_stream_moderate_sndbuf(sk);
701 }
702 return NULL;
703 }
704
705 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
706 int large_allowed)
707 {
708 struct tcp_sock *tp = tcp_sk(sk);
709 u32 xmit_size_goal, old_size_goal;
710
711 xmit_size_goal = mss_now;
712
713 if (large_allowed && sk_can_gso(sk)) {
714 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
715 inet_csk(sk)->icsk_af_ops->net_header_len -
716 inet_csk(sk)->icsk_ext_hdr_len -
717 tp->tcp_header_len);
718
719 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
720
721 /* We try hard to avoid divides here */
722 old_size_goal = tp->xmit_size_goal_segs * mss_now;
723
724 if (likely(old_size_goal <= xmit_size_goal &&
725 old_size_goal + mss_now > xmit_size_goal)) {
726 xmit_size_goal = old_size_goal;
727 } else {
728 tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
729 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
730 }
731 }
732
733 return max(xmit_size_goal, mss_now);
734 }
735
736 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
737 {
738 int mss_now;
739
740 mss_now = tcp_current_mss(sk);
741 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
742
743 return mss_now;
744 }
745
746 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
747 size_t psize, int flags)
748 {
749 struct tcp_sock *tp = tcp_sk(sk);
750 int mss_now, size_goal;
751 int err;
752 ssize_t copied;
753 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
754
755 /* Wait for a connection to finish. */
756 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
757 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
758 goto out_err;
759
760 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
761
762 mss_now = tcp_send_mss(sk, &size_goal, flags);
763 copied = 0;
764
765 err = -EPIPE;
766 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
767 goto out_err;
768
769 while (psize > 0) {
770 struct sk_buff *skb = tcp_write_queue_tail(sk);
771 struct page *page = pages[poffset / PAGE_SIZE];
772 int copy, i, can_coalesce;
773 int offset = poffset % PAGE_SIZE;
774 int size = min_t(size_t, psize, PAGE_SIZE - offset);
775
776 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
777 new_segment:
778 if (!sk_stream_memory_free(sk))
779 goto wait_for_sndbuf;
780
781 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
782 if (!skb)
783 goto wait_for_memory;
784
785 skb_entail(sk, skb);
786 copy = size_goal;
787 }
788
789 if (copy > size)
790 copy = size;
791
792 i = skb_shinfo(skb)->nr_frags;
793 can_coalesce = skb_can_coalesce(skb, i, page, offset);
794 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
795 tcp_mark_push(tp, skb);
796 goto new_segment;
797 }
798 if (!sk_wmem_schedule(sk, copy))
799 goto wait_for_memory;
800
801 if (can_coalesce) {
802 skb_shinfo(skb)->frags[i - 1].size += copy;
803 } else {
804 get_page(page);
805 skb_fill_page_desc(skb, i, page, offset, copy);
806 }
807
808 skb->len += copy;
809 skb->data_len += copy;
810 skb->truesize += copy;
811 sk->sk_wmem_queued += copy;
812 sk_mem_charge(sk, copy);
813 skb->ip_summed = CHECKSUM_PARTIAL;
814 tp->write_seq += copy;
815 TCP_SKB_CB(skb)->end_seq += copy;
816 skb_shinfo(skb)->gso_segs = 0;
817
818 if (!copied)
819 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
820
821 copied += copy;
822 poffset += copy;
823 if (!(psize -= copy))
824 goto out;
825
826 if (skb->len < size_goal || (flags & MSG_OOB))
827 continue;
828
829 if (forced_push(tp)) {
830 tcp_mark_push(tp, skb);
831 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
832 } else if (skb == tcp_send_head(sk))
833 tcp_push_one(sk, mss_now);
834 continue;
835
836 wait_for_sndbuf:
837 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
838 wait_for_memory:
839 if (copied)
840 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
841
842 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
843 goto do_error;
844
845 mss_now = tcp_send_mss(sk, &size_goal, flags);
846 }
847
848 out:
849 if (copied)
850 tcp_push(sk, flags, mss_now, tp->nonagle);
851 return copied;
852
853 do_error:
854 if (copied)
855 goto out;
856 out_err:
857 return sk_stream_error(sk, flags, err);
858 }
859
860 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
861 size_t size, int flags)
862 {
863 ssize_t res;
864 struct sock *sk = sock->sk;
865
866 if (!(sk->sk_route_caps & NETIF_F_SG) ||
867 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
868 return sock_no_sendpage(sock, page, offset, size, flags);
869
870 lock_sock(sk);
871 TCP_CHECK_TIMER(sk);
872 res = do_tcp_sendpages(sk, &page, offset, size, flags);
873 TCP_CHECK_TIMER(sk);
874 release_sock(sk);
875 return res;
876 }
877
878 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
879 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
880
881 static inline int select_size(struct sock *sk, int sg)
882 {
883 struct tcp_sock *tp = tcp_sk(sk);
884 int tmp = tp->mss_cache;
885
886 if (sg) {
887 if (sk_can_gso(sk))
888 tmp = 0;
889 else {
890 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
891
892 if (tmp >= pgbreak &&
893 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
894 tmp = pgbreak;
895 }
896 }
897
898 return tmp;
899 }
900
901 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
902 size_t size)
903 {
904 struct sock *sk = sock->sk;
905 struct iovec *iov;
906 struct tcp_sock *tp = tcp_sk(sk);
907 struct sk_buff *skb;
908 int iovlen, flags;
909 int mss_now, size_goal;
910 int sg, err, copied;
911 long timeo;
912
913 lock_sock(sk);
914 TCP_CHECK_TIMER(sk);
915
916 flags = msg->msg_flags;
917 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
918
919 /* Wait for a connection to finish. */
920 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
921 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
922 goto out_err;
923
924 /* This should be in poll */
925 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
926
927 mss_now = tcp_send_mss(sk, &size_goal, flags);
928
929 /* Ok commence sending. */
930 iovlen = msg->msg_iovlen;
931 iov = msg->msg_iov;
932 copied = 0;
933
934 err = -EPIPE;
935 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
936 goto out_err;
937
938 sg = sk->sk_route_caps & NETIF_F_SG;
939
940 while (--iovlen >= 0) {
941 int seglen = iov->iov_len;
942 unsigned char __user *from = iov->iov_base;
943
944 iov++;
945
946 while (seglen > 0) {
947 int copy = 0;
948 int max = size_goal;
949
950 skb = tcp_write_queue_tail(sk);
951 if (tcp_send_head(sk)) {
952 if (skb->ip_summed == CHECKSUM_NONE)
953 max = mss_now;
954 copy = max - skb->len;
955 }
956
957 if (copy <= 0) {
958 new_segment:
959 /* Allocate new segment. If the interface is SG,
960 * allocate skb fitting to single page.
961 */
962 if (!sk_stream_memory_free(sk))
963 goto wait_for_sndbuf;
964
965 skb = sk_stream_alloc_skb(sk,
966 select_size(sk, sg),
967 sk->sk_allocation);
968 if (!skb)
969 goto wait_for_memory;
970
971 /*
972 * Check whether we can use HW checksum.
973 */
974 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
975 skb->ip_summed = CHECKSUM_PARTIAL;
976
977 skb_entail(sk, skb);
978 copy = size_goal;
979 max = size_goal;
980 }
981
982 /* Try to append data to the end of skb. */
983 if (copy > seglen)
984 copy = seglen;
985
986 /* Where to copy to? */
987 if (skb_tailroom(skb) > 0) {
988 /* We have some space in skb head. Superb! */
989 if (copy > skb_tailroom(skb))
990 copy = skb_tailroom(skb);
991 if ((err = skb_add_data(skb, from, copy)) != 0)
992 goto do_fault;
993 } else {
994 int merge = 0;
995 int i = skb_shinfo(skb)->nr_frags;
996 struct page *page = TCP_PAGE(sk);
997 int off = TCP_OFF(sk);
998
999 if (skb_can_coalesce(skb, i, page, off) &&
1000 off != PAGE_SIZE) {
1001 /* We can extend the last page
1002 * fragment. */
1003 merge = 1;
1004 } else if (i == MAX_SKB_FRAGS || !sg) {
1005 /* Need to add new fragment and cannot
1006 * do this because interface is non-SG,
1007 * or because all the page slots are
1008 * busy. */
1009 tcp_mark_push(tp, skb);
1010 goto new_segment;
1011 } else if (page) {
1012 if (off == PAGE_SIZE) {
1013 put_page(page);
1014 TCP_PAGE(sk) = page = NULL;
1015 off = 0;
1016 }
1017 } else
1018 off = 0;
1019
1020 if (copy > PAGE_SIZE - off)
1021 copy = PAGE_SIZE - off;
1022
1023 if (!sk_wmem_schedule(sk, copy))
1024 goto wait_for_memory;
1025
1026 if (!page) {
1027 /* Allocate new cache page. */
1028 if (!(page = sk_stream_alloc_page(sk)))
1029 goto wait_for_memory;
1030 }
1031
1032 /* Time to copy data. We are close to
1033 * the end! */
1034 err = skb_copy_to_page(sk, from, skb, page,
1035 off, copy);
1036 if (err) {
1037 /* If this page was new, give it to the
1038 * socket so it does not get leaked.
1039 */
1040 if (!TCP_PAGE(sk)) {
1041 TCP_PAGE(sk) = page;
1042 TCP_OFF(sk) = 0;
1043 }
1044 goto do_error;
1045 }
1046
1047 /* Update the skb. */
1048 if (merge) {
1049 skb_shinfo(skb)->frags[i - 1].size +=
1050 copy;
1051 } else {
1052 skb_fill_page_desc(skb, i, page, off, copy);
1053 if (TCP_PAGE(sk)) {
1054 get_page(page);
1055 } else if (off + copy < PAGE_SIZE) {
1056 get_page(page);
1057 TCP_PAGE(sk) = page;
1058 }
1059 }
1060
1061 TCP_OFF(sk) = off + copy;
1062 }
1063
1064 if (!copied)
1065 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
1066
1067 tp->write_seq += copy;
1068 TCP_SKB_CB(skb)->end_seq += copy;
1069 skb_shinfo(skb)->gso_segs = 0;
1070
1071 from += copy;
1072 copied += copy;
1073 if ((seglen -= copy) == 0 && iovlen == 0)
1074 goto out;
1075
1076 if (skb->len < max || (flags & MSG_OOB))
1077 continue;
1078
1079 if (forced_push(tp)) {
1080 tcp_mark_push(tp, skb);
1081 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1082 } else if (skb == tcp_send_head(sk))
1083 tcp_push_one(sk, mss_now);
1084 continue;
1085
1086 wait_for_sndbuf:
1087 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1088 wait_for_memory:
1089 if (copied)
1090 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1091
1092 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1093 goto do_error;
1094
1095 mss_now = tcp_send_mss(sk, &size_goal, flags);
1096 }
1097 }
1098
1099 out:
1100 if (copied)
1101 tcp_push(sk, flags, mss_now, tp->nonagle);
1102 TCP_CHECK_TIMER(sk);
1103 release_sock(sk);
1104 return copied;
1105
1106 do_fault:
1107 if (!skb->len) {
1108 tcp_unlink_write_queue(skb, sk);
1109 /* It is the one place in all of TCP, except connection
1110 * reset, where we can be unlinking the send_head.
1111 */
1112 tcp_check_send_head(sk, skb);
1113 sk_wmem_free_skb(sk, skb);
1114 }
1115
1116 do_error:
1117 if (copied)
1118 goto out;
1119 out_err:
1120 err = sk_stream_error(sk, flags, err);
1121 TCP_CHECK_TIMER(sk);
1122 release_sock(sk);
1123 return err;
1124 }
1125
1126 /*
1127 * Handle reading urgent data. BSD has very simple semantics for
1128 * this, no blocking and very strange errors 8)
1129 */
1130
1131 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1132 {
1133 struct tcp_sock *tp = tcp_sk(sk);
1134
1135 /* No URG data to read. */
1136 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1137 tp->urg_data == TCP_URG_READ)
1138 return -EINVAL; /* Yes this is right ! */
1139
1140 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1141 return -ENOTCONN;
1142
1143 if (tp->urg_data & TCP_URG_VALID) {
1144 int err = 0;
1145 char c = tp->urg_data;
1146
1147 if (!(flags & MSG_PEEK))
1148 tp->urg_data = TCP_URG_READ;
1149
1150 /* Read urgent data. */
1151 msg->msg_flags |= MSG_OOB;
1152
1153 if (len > 0) {
1154 if (!(flags & MSG_TRUNC))
1155 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1156 len = 1;
1157 } else
1158 msg->msg_flags |= MSG_TRUNC;
1159
1160 return err ? -EFAULT : len;
1161 }
1162
1163 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1164 return 0;
1165
1166 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1167 * the available implementations agree in this case:
1168 * this call should never block, independent of the
1169 * blocking state of the socket.
1170 * Mike <pall@rz.uni-karlsruhe.de>
1171 */
1172 return -EAGAIN;
1173 }
1174
1175 /* Clean up the receive buffer for full frames taken by the user,
1176 * then send an ACK if necessary. COPIED is the number of bytes
1177 * tcp_recvmsg has given to the user so far, it speeds up the
1178 * calculation of whether or not we must ACK for the sake of
1179 * a window update.
1180 */
1181 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1182 {
1183 struct tcp_sock *tp = tcp_sk(sk);
1184 int time_to_ack = 0;
1185
1186 #if TCP_DEBUG
1187 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1188
1189 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1190 KERN_INFO "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1191 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1192 #endif
1193
1194 if (inet_csk_ack_scheduled(sk)) {
1195 const struct inet_connection_sock *icsk = inet_csk(sk);
1196 /* Delayed ACKs frequently hit locked sockets during bulk
1197 * receive. */
1198 if (icsk->icsk_ack.blocked ||
1199 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1200 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1201 /*
1202 * If this read emptied read buffer, we send ACK, if
1203 * connection is not bidirectional, user drained
1204 * receive buffer and there was a small segment
1205 * in queue.
1206 */
1207 (copied > 0 &&
1208 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1209 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1210 !icsk->icsk_ack.pingpong)) &&
1211 !atomic_read(&sk->sk_rmem_alloc)))
1212 time_to_ack = 1;
1213 }
1214
1215 /* We send an ACK if we can now advertise a non-zero window
1216 * which has been raised "significantly".
1217 *
1218 * Even if window raised up to infinity, do not send window open ACK
1219 * in states, where we will not receive more. It is useless.
1220 */
1221 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1222 __u32 rcv_window_now = tcp_receive_window(tp);
1223
1224 /* Optimize, __tcp_select_window() is not cheap. */
1225 if (2*rcv_window_now <= tp->window_clamp) {
1226 __u32 new_window = __tcp_select_window(sk);
1227
1228 /* Send ACK now, if this read freed lots of space
1229 * in our buffer. Certainly, new_window is new window.
1230 * We can advertise it now, if it is not less than current one.
1231 * "Lots" means "at least twice" here.
1232 */
1233 if (new_window && new_window >= 2 * rcv_window_now)
1234 time_to_ack = 1;
1235 }
1236 }
1237 if (time_to_ack)
1238 tcp_send_ack(sk);
1239 }
1240
1241 static void tcp_prequeue_process(struct sock *sk)
1242 {
1243 struct sk_buff *skb;
1244 struct tcp_sock *tp = tcp_sk(sk);
1245
1246 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1247
1248 /* RX process wants to run with disabled BHs, though it is not
1249 * necessary */
1250 local_bh_disable();
1251 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1252 sk_backlog_rcv(sk, skb);
1253 local_bh_enable();
1254
1255 /* Clear memory counter. */
1256 tp->ucopy.memory = 0;
1257 }
1258
1259 #ifdef CONFIG_NET_DMA
1260 static void tcp_service_net_dma(struct sock *sk, bool wait)
1261 {
1262 dma_cookie_t done, used;
1263 dma_cookie_t last_issued;
1264 struct tcp_sock *tp = tcp_sk(sk);
1265
1266 if (!tp->ucopy.dma_chan)
1267 return;
1268
1269 last_issued = tp->ucopy.dma_cookie;
1270 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1271
1272 do {
1273 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1274 last_issued, &done,
1275 &used) == DMA_SUCCESS) {
1276 /* Safe to free early-copied skbs now */
1277 __skb_queue_purge(&sk->sk_async_wait_queue);
1278 break;
1279 } else {
1280 struct sk_buff *skb;
1281 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1282 (dma_async_is_complete(skb->dma_cookie, done,
1283 used) == DMA_SUCCESS)) {
1284 __skb_dequeue(&sk->sk_async_wait_queue);
1285 kfree_skb(skb);
1286 }
1287 }
1288 } while (wait);
1289 }
1290 #endif
1291
1292 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1293 {
1294 struct sk_buff *skb;
1295 u32 offset;
1296
1297 skb_queue_walk(&sk->sk_receive_queue, skb) {
1298 offset = seq - TCP_SKB_CB(skb)->seq;
1299 if (tcp_hdr(skb)->syn)
1300 offset--;
1301 if (offset < skb->len || tcp_hdr(skb)->fin) {
1302 *off = offset;
1303 return skb;
1304 }
1305 }
1306 return NULL;
1307 }
1308
1309 /*
1310 * This routine provides an alternative to tcp_recvmsg() for routines
1311 * that would like to handle copying from skbuffs directly in 'sendfile'
1312 * fashion.
1313 * Note:
1314 * - It is assumed that the socket was locked by the caller.
1315 * - The routine does not block.
1316 * - At present, there is no support for reading OOB data
1317 * or for 'peeking' the socket using this routine
1318 * (although both would be easy to implement).
1319 */
1320 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1321 sk_read_actor_t recv_actor)
1322 {
1323 struct sk_buff *skb;
1324 struct tcp_sock *tp = tcp_sk(sk);
1325 u32 seq = tp->copied_seq;
1326 u32 offset;
1327 int copied = 0;
1328
1329 if (sk->sk_state == TCP_LISTEN)
1330 return -ENOTCONN;
1331 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1332 if (offset < skb->len) {
1333 int used;
1334 size_t len;
1335
1336 len = skb->len - offset;
1337 /* Stop reading if we hit a patch of urgent data */
1338 if (tp->urg_data) {
1339 u32 urg_offset = tp->urg_seq - seq;
1340 if (urg_offset < len)
1341 len = urg_offset;
1342 if (!len)
1343 break;
1344 }
1345 used = recv_actor(desc, skb, offset, len);
1346 if (used < 0) {
1347 if (!copied)
1348 copied = used;
1349 break;
1350 } else if (used <= len) {
1351 seq += used;
1352 copied += used;
1353 offset += used;
1354 }
1355 /*
1356 * If recv_actor drops the lock (e.g. TCP splice
1357 * receive) the skb pointer might be invalid when
1358 * getting here: tcp_collapse might have deleted it
1359 * while aggregating skbs from the socket queue.
1360 */
1361 skb = tcp_recv_skb(sk, seq-1, &offset);
1362 if (!skb || (offset+1 != skb->len))
1363 break;
1364 }
1365 if (tcp_hdr(skb)->fin) {
1366 sk_eat_skb(sk, skb, 0);
1367 ++seq;
1368 break;
1369 }
1370 sk_eat_skb(sk, skb, 0);
1371 if (!desc->count)
1372 break;
1373 tp->copied_seq = seq;
1374 }
1375 tp->copied_seq = seq;
1376
1377 tcp_rcv_space_adjust(sk);
1378
1379 /* Clean up data we have read: This will do ACK frames. */
1380 if (copied > 0)
1381 tcp_cleanup_rbuf(sk, copied);
1382 return copied;
1383 }
1384
1385 /*
1386 * This routine copies from a sock struct into the user buffer.
1387 *
1388 * Technical note: in 2.3 we work on _locked_ socket, so that
1389 * tricks with *seq access order and skb->users are not required.
1390 * Probably, code can be easily improved even more.
1391 */
1392
1393 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1394 size_t len, int nonblock, int flags, int *addr_len)
1395 {
1396 struct tcp_sock *tp = tcp_sk(sk);
1397 int copied = 0;
1398 u32 peek_seq;
1399 u32 *seq;
1400 unsigned long used;
1401 int err;
1402 int target; /* Read at least this many bytes */
1403 long timeo;
1404 struct task_struct *user_recv = NULL;
1405 int copied_early = 0;
1406 struct sk_buff *skb;
1407 u32 urg_hole = 0;
1408
1409 lock_sock(sk);
1410
1411 TCP_CHECK_TIMER(sk);
1412
1413 err = -ENOTCONN;
1414 if (sk->sk_state == TCP_LISTEN)
1415 goto out;
1416
1417 timeo = sock_rcvtimeo(sk, nonblock);
1418
1419 /* Urgent data needs to be handled specially. */
1420 if (flags & MSG_OOB)
1421 goto recv_urg;
1422
1423 seq = &tp->copied_seq;
1424 if (flags & MSG_PEEK) {
1425 peek_seq = tp->copied_seq;
1426 seq = &peek_seq;
1427 }
1428
1429 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1430
1431 #ifdef CONFIG_NET_DMA
1432 tp->ucopy.dma_chan = NULL;
1433 preempt_disable();
1434 skb = skb_peek_tail(&sk->sk_receive_queue);
1435 {
1436 int available = 0;
1437
1438 if (skb)
1439 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1440 if ((available < target) &&
1441 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1442 !sysctl_tcp_low_latency &&
1443 dma_find_channel(DMA_MEMCPY)) {
1444 preempt_enable_no_resched();
1445 tp->ucopy.pinned_list =
1446 dma_pin_iovec_pages(msg->msg_iov, len);
1447 } else {
1448 preempt_enable_no_resched();
1449 }
1450 }
1451 #endif
1452
1453 do {
1454 u32 offset;
1455
1456 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1457 if (tp->urg_data && tp->urg_seq == *seq) {
1458 if (copied)
1459 break;
1460 if (signal_pending(current)) {
1461 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1462 break;
1463 }
1464 }
1465
1466 /* Next get a buffer. */
1467
1468 skb_queue_walk(&sk->sk_receive_queue, skb) {
1469 /* Now that we have two receive queues this
1470 * shouldn't happen.
1471 */
1472 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1473 KERN_INFO "recvmsg bug: copied %X "
1474 "seq %X rcvnxt %X fl %X\n", *seq,
1475 TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1476 flags))
1477 break;
1478
1479 offset = *seq - TCP_SKB_CB(skb)->seq;
1480 if (tcp_hdr(skb)->syn)
1481 offset--;
1482 if (offset < skb->len)
1483 goto found_ok_skb;
1484 if (tcp_hdr(skb)->fin)
1485 goto found_fin_ok;
1486 WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "
1487 "copied %X seq %X rcvnxt %X fl %X\n",
1488 *seq, TCP_SKB_CB(skb)->seq,
1489 tp->rcv_nxt, flags);
1490 }
1491
1492 /* Well, if we have backlog, try to process it now yet. */
1493
1494 if (copied >= target && !sk->sk_backlog.tail)
1495 break;
1496
1497 if (copied) {
1498 if (sk->sk_err ||
1499 sk->sk_state == TCP_CLOSE ||
1500 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1501 !timeo ||
1502 signal_pending(current))
1503 break;
1504 } else {
1505 if (sock_flag(sk, SOCK_DONE))
1506 break;
1507
1508 if (sk->sk_err) {
1509 copied = sock_error(sk);
1510 break;
1511 }
1512
1513 if (sk->sk_shutdown & RCV_SHUTDOWN)
1514 break;
1515
1516 if (sk->sk_state == TCP_CLOSE) {
1517 if (!sock_flag(sk, SOCK_DONE)) {
1518 /* This occurs when user tries to read
1519 * from never connected socket.
1520 */
1521 copied = -ENOTCONN;
1522 break;
1523 }
1524 break;
1525 }
1526
1527 if (!timeo) {
1528 copied = -EAGAIN;
1529 break;
1530 }
1531
1532 if (signal_pending(current)) {
1533 copied = sock_intr_errno(timeo);
1534 break;
1535 }
1536 }
1537
1538 tcp_cleanup_rbuf(sk, copied);
1539
1540 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1541 /* Install new reader */
1542 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1543 user_recv = current;
1544 tp->ucopy.task = user_recv;
1545 tp->ucopy.iov = msg->msg_iov;
1546 }
1547
1548 tp->ucopy.len = len;
1549
1550 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1551 !(flags & (MSG_PEEK | MSG_TRUNC)));
1552
1553 /* Ugly... If prequeue is not empty, we have to
1554 * process it before releasing socket, otherwise
1555 * order will be broken at second iteration.
1556 * More elegant solution is required!!!
1557 *
1558 * Look: we have the following (pseudo)queues:
1559 *
1560 * 1. packets in flight
1561 * 2. backlog
1562 * 3. prequeue
1563 * 4. receive_queue
1564 *
1565 * Each queue can be processed only if the next ones
1566 * are empty. At this point we have empty receive_queue.
1567 * But prequeue _can_ be not empty after 2nd iteration,
1568 * when we jumped to start of loop because backlog
1569 * processing added something to receive_queue.
1570 * We cannot release_sock(), because backlog contains
1571 * packets arrived _after_ prequeued ones.
1572 *
1573 * Shortly, algorithm is clear --- to process all
1574 * the queues in order. We could make it more directly,
1575 * requeueing packets from backlog to prequeue, if
1576 * is not empty. It is more elegant, but eats cycles,
1577 * unfortunately.
1578 */
1579 if (!skb_queue_empty(&tp->ucopy.prequeue))
1580 goto do_prequeue;
1581
1582 /* __ Set realtime policy in scheduler __ */
1583 }
1584
1585 #ifdef CONFIG_NET_DMA
1586 if (tp->ucopy.dma_chan)
1587 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1588 #endif
1589 if (copied >= target) {
1590 /* Do not sleep, just process backlog. */
1591 release_sock(sk);
1592 lock_sock(sk);
1593 } else
1594 sk_wait_data(sk, &timeo);
1595
1596 #ifdef CONFIG_NET_DMA
1597 tcp_service_net_dma(sk, false); /* Don't block */
1598 tp->ucopy.wakeup = 0;
1599 #endif
1600
1601 if (user_recv) {
1602 int chunk;
1603
1604 /* __ Restore normal policy in scheduler __ */
1605
1606 if ((chunk = len - tp->ucopy.len) != 0) {
1607 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1608 len -= chunk;
1609 copied += chunk;
1610 }
1611
1612 if (tp->rcv_nxt == tp->copied_seq &&
1613 !skb_queue_empty(&tp->ucopy.prequeue)) {
1614 do_prequeue:
1615 tcp_prequeue_process(sk);
1616
1617 if ((chunk = len - tp->ucopy.len) != 0) {
1618 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1619 len -= chunk;
1620 copied += chunk;
1621 }
1622 }
1623 }
1624 if ((flags & MSG_PEEK) &&
1625 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1626 if (net_ratelimit())
1627 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1628 current->comm, task_pid_nr(current));
1629 peek_seq = tp->copied_seq;
1630 }
1631 continue;
1632
1633 found_ok_skb:
1634 /* Ok so how much can we use? */
1635 used = skb->len - offset;
1636 if (len < used)
1637 used = len;
1638
1639 /* Do we have urgent data here? */
1640 if (tp->urg_data) {
1641 u32 urg_offset = tp->urg_seq - *seq;
1642 if (urg_offset < used) {
1643 if (!urg_offset) {
1644 if (!sock_flag(sk, SOCK_URGINLINE)) {
1645 ++*seq;
1646 urg_hole++;
1647 offset++;
1648 used--;
1649 if (!used)
1650 goto skip_copy;
1651 }
1652 } else
1653 used = urg_offset;
1654 }
1655 }
1656
1657 if (!(flags & MSG_TRUNC)) {
1658 #ifdef CONFIG_NET_DMA
1659 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1660 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1661
1662 if (tp->ucopy.dma_chan) {
1663 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1664 tp->ucopy.dma_chan, skb, offset,
1665 msg->msg_iov, used,
1666 tp->ucopy.pinned_list);
1667
1668 if (tp->ucopy.dma_cookie < 0) {
1669
1670 printk(KERN_ALERT "dma_cookie < 0\n");
1671
1672 /* Exception. Bailout! */
1673 if (!copied)
1674 copied = -EFAULT;
1675 break;
1676 }
1677
1678 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1679
1680 if ((offset + used) == skb->len)
1681 copied_early = 1;
1682
1683 } else
1684 #endif
1685 {
1686 err = skb_copy_datagram_iovec(skb, offset,
1687 msg->msg_iov, used);
1688 if (err) {
1689 /* Exception. Bailout! */
1690 if (!copied)
1691 copied = -EFAULT;
1692 break;
1693 }
1694 }
1695 }
1696
1697 *seq += used;
1698 copied += used;
1699 len -= used;
1700
1701 tcp_rcv_space_adjust(sk);
1702
1703 skip_copy:
1704 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1705 tp->urg_data = 0;
1706 tcp_fast_path_check(sk);
1707 }
1708 if (used + offset < skb->len)
1709 continue;
1710
1711 if (tcp_hdr(skb)->fin)
1712 goto found_fin_ok;
1713 if (!(flags & MSG_PEEK)) {
1714 sk_eat_skb(sk, skb, copied_early);
1715 copied_early = 0;
1716 }
1717 continue;
1718
1719 found_fin_ok:
1720 /* Process the FIN. */
1721 ++*seq;
1722 if (!(flags & MSG_PEEK)) {
1723 sk_eat_skb(sk, skb, copied_early);
1724 copied_early = 0;
1725 }
1726 break;
1727 } while (len > 0);
1728
1729 if (user_recv) {
1730 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1731 int chunk;
1732
1733 tp->ucopy.len = copied > 0 ? len : 0;
1734
1735 tcp_prequeue_process(sk);
1736
1737 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1738 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1739 len -= chunk;
1740 copied += chunk;
1741 }
1742 }
1743
1744 tp->ucopy.task = NULL;
1745 tp->ucopy.len = 0;
1746 }
1747
1748 #ifdef CONFIG_NET_DMA
1749 tcp_service_net_dma(sk, true); /* Wait for queue to drain */
1750 tp->ucopy.dma_chan = NULL;
1751
1752 if (tp->ucopy.pinned_list) {
1753 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1754 tp->ucopy.pinned_list = NULL;
1755 }
1756 #endif
1757
1758 /* According to UNIX98, msg_name/msg_namelen are ignored
1759 * on connected socket. I was just happy when found this 8) --ANK
1760 */
1761
1762 /* Clean up data we have read: This will do ACK frames. */
1763 tcp_cleanup_rbuf(sk, copied);
1764
1765 TCP_CHECK_TIMER(sk);
1766 release_sock(sk);
1767 return copied;
1768
1769 out:
1770 TCP_CHECK_TIMER(sk);
1771 release_sock(sk);
1772 return err;
1773
1774 recv_urg:
1775 err = tcp_recv_urg(sk, msg, len, flags);
1776 goto out;
1777 }
1778
1779 void tcp_set_state(struct sock *sk, int state)
1780 {
1781 int oldstate = sk->sk_state;
1782
1783 switch (state) {
1784 case TCP_ESTABLISHED:
1785 if (oldstate != TCP_ESTABLISHED)
1786 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1787 break;
1788
1789 case TCP_CLOSE:
1790 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1791 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1792
1793 sk->sk_prot->unhash(sk);
1794 if (inet_csk(sk)->icsk_bind_hash &&
1795 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1796 inet_put_port(sk);
1797 /* fall through */
1798 default:
1799 if (oldstate == TCP_ESTABLISHED)
1800 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1801 }
1802
1803 /* Change state AFTER socket is unhashed to avoid closed
1804 * socket sitting in hash tables.
1805 */
1806 sk->sk_state = state;
1807
1808 #ifdef STATE_TRACE
1809 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1810 #endif
1811 }
1812 EXPORT_SYMBOL_GPL(tcp_set_state);
1813
1814 /*
1815 * State processing on a close. This implements the state shift for
1816 * sending our FIN frame. Note that we only send a FIN for some
1817 * states. A shutdown() may have already sent the FIN, or we may be
1818 * closed.
1819 */
1820
1821 static const unsigned char new_state[16] = {
1822 /* current state: new state: action: */
1823 /* (Invalid) */ TCP_CLOSE,
1824 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1825 /* TCP_SYN_SENT */ TCP_CLOSE,
1826 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1827 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1828 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1829 /* TCP_TIME_WAIT */ TCP_CLOSE,
1830 /* TCP_CLOSE */ TCP_CLOSE,
1831 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1832 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1833 /* TCP_LISTEN */ TCP_CLOSE,
1834 /* TCP_CLOSING */ TCP_CLOSING,
1835 };
1836
1837 static int tcp_close_state(struct sock *sk)
1838 {
1839 int next = (int)new_state[sk->sk_state];
1840 int ns = next & TCP_STATE_MASK;
1841
1842 tcp_set_state(sk, ns);
1843
1844 return next & TCP_ACTION_FIN;
1845 }
1846
1847 /*
1848 * Shutdown the sending side of a connection. Much like close except
1849 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1850 */
1851
1852 void tcp_shutdown(struct sock *sk, int how)
1853 {
1854 /* We need to grab some memory, and put together a FIN,
1855 * and then put it into the queue to be sent.
1856 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1857 */
1858 if (!(how & SEND_SHUTDOWN))
1859 return;
1860
1861 /* If we've already sent a FIN, or it's a closed state, skip this. */
1862 if ((1 << sk->sk_state) &
1863 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1864 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1865 /* Clear out any half completed packets. FIN if needed. */
1866 if (tcp_close_state(sk))
1867 tcp_send_fin(sk);
1868 }
1869 }
1870
1871 void tcp_close(struct sock *sk, long timeout)
1872 {
1873 struct sk_buff *skb;
1874 int data_was_unread = 0;
1875 int state;
1876
1877 lock_sock(sk);
1878 sk->sk_shutdown = SHUTDOWN_MASK;
1879
1880 if (sk->sk_state == TCP_LISTEN) {
1881 tcp_set_state(sk, TCP_CLOSE);
1882
1883 /* Special case. */
1884 inet_csk_listen_stop(sk);
1885
1886 goto adjudge_to_death;
1887 }
1888
1889 /* We need to flush the recv. buffs. We do this only on the
1890 * descriptor close, not protocol-sourced closes, because the
1891 * reader process may not have drained the data yet!
1892 */
1893 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1894 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1895 tcp_hdr(skb)->fin;
1896 data_was_unread += len;
1897 __kfree_skb(skb);
1898 }
1899
1900 sk_mem_reclaim(sk);
1901
1902 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1903 * data was lost. To witness the awful effects of the old behavior of
1904 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1905 * GET in an FTP client, suspend the process, wait for the client to
1906 * advertise a zero window, then kill -9 the FTP client, wheee...
1907 * Note: timeout is always zero in such a case.
1908 */
1909 if (data_was_unread) {
1910 /* Unread data was tossed, zap the connection. */
1911 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1912 tcp_set_state(sk, TCP_CLOSE);
1913 tcp_send_active_reset(sk, sk->sk_allocation);
1914 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1915 /* Check zero linger _after_ checking for unread data. */
1916 sk->sk_prot->disconnect(sk, 0);
1917 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1918 } else if (tcp_close_state(sk)) {
1919 /* We FIN if the application ate all the data before
1920 * zapping the connection.
1921 */
1922
1923 /* RED-PEN. Formally speaking, we have broken TCP state
1924 * machine. State transitions:
1925 *
1926 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1927 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1928 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1929 *
1930 * are legal only when FIN has been sent (i.e. in window),
1931 * rather than queued out of window. Purists blame.
1932 *
1933 * F.e. "RFC state" is ESTABLISHED,
1934 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1935 *
1936 * The visible declinations are that sometimes
1937 * we enter time-wait state, when it is not required really
1938 * (harmless), do not send active resets, when they are
1939 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1940 * they look as CLOSING or LAST_ACK for Linux)
1941 * Probably, I missed some more holelets.
1942 * --ANK
1943 */
1944 tcp_send_fin(sk);
1945 }
1946
1947 sk_stream_wait_close(sk, timeout);
1948
1949 adjudge_to_death:
1950 state = sk->sk_state;
1951 sock_hold(sk);
1952 sock_orphan(sk);
1953
1954 /* It is the last release_sock in its life. It will remove backlog. */
1955 release_sock(sk);
1956
1957
1958 /* Now socket is owned by kernel and we acquire BH lock
1959 to finish close. No need to check for user refs.
1960 */
1961 local_bh_disable();
1962 bh_lock_sock(sk);
1963 WARN_ON(sock_owned_by_user(sk));
1964
1965 percpu_counter_inc(sk->sk_prot->orphan_count);
1966
1967 /* Have we already been destroyed by a softirq or backlog? */
1968 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1969 goto out;
1970
1971 /* This is a (useful) BSD violating of the RFC. There is a
1972 * problem with TCP as specified in that the other end could
1973 * keep a socket open forever with no application left this end.
1974 * We use a 3 minute timeout (about the same as BSD) then kill
1975 * our end. If they send after that then tough - BUT: long enough
1976 * that we won't make the old 4*rto = almost no time - whoops
1977 * reset mistake.
1978 *
1979 * Nope, it was not mistake. It is really desired behaviour
1980 * f.e. on http servers, when such sockets are useless, but
1981 * consume significant resources. Let's do it with special
1982 * linger2 option. --ANK
1983 */
1984
1985 if (sk->sk_state == TCP_FIN_WAIT2) {
1986 struct tcp_sock *tp = tcp_sk(sk);
1987 if (tp->linger2 < 0) {
1988 tcp_set_state(sk, TCP_CLOSE);
1989 tcp_send_active_reset(sk, GFP_ATOMIC);
1990 NET_INC_STATS_BH(sock_net(sk),
1991 LINUX_MIB_TCPABORTONLINGER);
1992 } else {
1993 const int tmo = tcp_fin_time(sk);
1994
1995 if (tmo > TCP_TIMEWAIT_LEN) {
1996 inet_csk_reset_keepalive_timer(sk,
1997 tmo - TCP_TIMEWAIT_LEN);
1998 } else {
1999 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2000 goto out;
2001 }
2002 }
2003 }
2004 if (sk->sk_state != TCP_CLOSE) {
2005 int orphan_count = percpu_counter_read_positive(
2006 sk->sk_prot->orphan_count);
2007
2008 sk_mem_reclaim(sk);
2009 if (tcp_too_many_orphans(sk, orphan_count)) {
2010 if (net_ratelimit())
2011 printk(KERN_INFO "TCP: too many of orphaned "
2012 "sockets\n");
2013 tcp_set_state(sk, TCP_CLOSE);
2014 tcp_send_active_reset(sk, GFP_ATOMIC);
2015 NET_INC_STATS_BH(sock_net(sk),
2016 LINUX_MIB_TCPABORTONMEMORY);
2017 }
2018 }
2019
2020 if (sk->sk_state == TCP_CLOSE)
2021 inet_csk_destroy_sock(sk);
2022 /* Otherwise, socket is reprieved until protocol close. */
2023
2024 out:
2025 bh_unlock_sock(sk);
2026 local_bh_enable();
2027 sock_put(sk);
2028 }
2029
2030 /* These states need RST on ABORT according to RFC793 */
2031
2032 static inline int tcp_need_reset(int state)
2033 {
2034 return (1 << state) &
2035 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2036 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2037 }
2038
2039 int tcp_disconnect(struct sock *sk, int flags)
2040 {
2041 struct inet_sock *inet = inet_sk(sk);
2042 struct inet_connection_sock *icsk = inet_csk(sk);
2043 struct tcp_sock *tp = tcp_sk(sk);
2044 int err = 0;
2045 int old_state = sk->sk_state;
2046
2047 if (old_state != TCP_CLOSE)
2048 tcp_set_state(sk, TCP_CLOSE);
2049
2050 /* ABORT function of RFC793 */
2051 if (old_state == TCP_LISTEN) {
2052 inet_csk_listen_stop(sk);
2053 } else if (tcp_need_reset(old_state) ||
2054 (tp->snd_nxt != tp->write_seq &&
2055 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2056 /* The last check adjusts for discrepancy of Linux wrt. RFC
2057 * states
2058 */
2059 tcp_send_active_reset(sk, gfp_any());
2060 sk->sk_err = ECONNRESET;
2061 } else if (old_state == TCP_SYN_SENT)
2062 sk->sk_err = ECONNRESET;
2063
2064 tcp_clear_xmit_timers(sk);
2065 __skb_queue_purge(&sk->sk_receive_queue);
2066 tcp_write_queue_purge(sk);
2067 __skb_queue_purge(&tp->out_of_order_queue);
2068 #ifdef CONFIG_NET_DMA
2069 __skb_queue_purge(&sk->sk_async_wait_queue);
2070 #endif
2071
2072 inet->inet_dport = 0;
2073
2074 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2075 inet_reset_saddr(sk);
2076
2077 sk->sk_shutdown = 0;
2078 sock_reset_flag(sk, SOCK_DONE);
2079 tp->srtt = 0;
2080 if ((tp->write_seq += tp->max_window + 2) == 0)
2081 tp->write_seq = 1;
2082 icsk->icsk_backoff = 0;
2083 tp->snd_cwnd = 2;
2084 icsk->icsk_probes_out = 0;
2085 tp->packets_out = 0;
2086 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2087 tp->snd_cwnd_cnt = 0;
2088 tp->bytes_acked = 0;
2089 tp->window_clamp = 0;
2090 tcp_set_ca_state(sk, TCP_CA_Open);
2091 tcp_clear_retrans(tp);
2092 inet_csk_delack_init(sk);
2093 tcp_init_send_head(sk);
2094 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2095 __sk_dst_reset(sk);
2096
2097 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2098
2099 sk->sk_error_report(sk);
2100 return err;
2101 }
2102
2103 /*
2104 * Socket option code for TCP.
2105 */
2106 static int do_tcp_setsockopt(struct sock *sk, int level,
2107 int optname, char __user *optval, unsigned int optlen)
2108 {
2109 struct tcp_sock *tp = tcp_sk(sk);
2110 struct inet_connection_sock *icsk = inet_csk(sk);
2111 int val;
2112 int err = 0;
2113
2114 /* These are data/string values, all the others are ints */
2115 switch (optname) {
2116 case TCP_CONGESTION: {
2117 char name[TCP_CA_NAME_MAX];
2118
2119 if (optlen < 1)
2120 return -EINVAL;
2121
2122 val = strncpy_from_user(name, optval,
2123 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2124 if (val < 0)
2125 return -EFAULT;
2126 name[val] = 0;
2127
2128 lock_sock(sk);
2129 err = tcp_set_congestion_control(sk, name);
2130 release_sock(sk);
2131 return err;
2132 }
2133 case TCP_COOKIE_TRANSACTIONS: {
2134 struct tcp_cookie_transactions ctd;
2135 struct tcp_cookie_values *cvp = NULL;
2136
2137 if (sizeof(ctd) > optlen)
2138 return -EINVAL;
2139 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2140 return -EFAULT;
2141
2142 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2143 ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2144 return -EINVAL;
2145
2146 if (ctd.tcpct_cookie_desired == 0) {
2147 /* default to global value */
2148 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2149 ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2150 ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2151 return -EINVAL;
2152 }
2153
2154 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2155 /* Supercedes all other values */
2156 lock_sock(sk);
2157 if (tp->cookie_values != NULL) {
2158 kref_put(&tp->cookie_values->kref,
2159 tcp_cookie_values_release);
2160 tp->cookie_values = NULL;
2161 }
2162 tp->rx_opt.cookie_in_always = 0; /* false */
2163 tp->rx_opt.cookie_out_never = 1; /* true */
2164 release_sock(sk);
2165 return err;
2166 }
2167
2168 /* Allocate ancillary memory before locking.
2169 */
2170 if (ctd.tcpct_used > 0 ||
2171 (tp->cookie_values == NULL &&
2172 (sysctl_tcp_cookie_size > 0 ||
2173 ctd.tcpct_cookie_desired > 0 ||
2174 ctd.tcpct_s_data_desired > 0))) {
2175 cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2176 GFP_KERNEL);
2177 if (cvp == NULL)
2178 return -ENOMEM;
2179 }
2180 lock_sock(sk);
2181 tp->rx_opt.cookie_in_always =
2182 (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2183 tp->rx_opt.cookie_out_never = 0; /* false */
2184
2185 if (tp->cookie_values != NULL) {
2186 if (cvp != NULL) {
2187 /* Changed values are recorded by a changed
2188 * pointer, ensuring the cookie will differ,
2189 * without separately hashing each value later.
2190 */
2191 kref_put(&tp->cookie_values->kref,
2192 tcp_cookie_values_release);
2193 kref_init(&cvp->kref);
2194 tp->cookie_values = cvp;
2195 } else {
2196 cvp = tp->cookie_values;
2197 }
2198 }
2199 if (cvp != NULL) {
2200 cvp->cookie_desired = ctd.tcpct_cookie_desired;
2201
2202 if (ctd.tcpct_used > 0) {
2203 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2204 ctd.tcpct_used);
2205 cvp->s_data_desired = ctd.tcpct_used;
2206 cvp->s_data_constant = 1; /* true */
2207 } else {
2208 /* No constant payload data. */
2209 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2210 cvp->s_data_constant = 0; /* false */
2211 }
2212 }
2213 release_sock(sk);
2214 return err;
2215 }
2216 default:
2217 /* fallthru */
2218 break;
2219 }
2220
2221 if (optlen < sizeof(int))
2222 return -EINVAL;
2223
2224 if (get_user(val, (int __user *)optval))
2225 return -EFAULT;
2226
2227 lock_sock(sk);
2228
2229 switch (optname) {
2230 case TCP_MAXSEG:
2231 /* Values greater than interface MTU won't take effect. However
2232 * at the point when this call is done we typically don't yet
2233 * know which interface is going to be used */
2234 if (val < 8 || val > MAX_TCP_WINDOW) {
2235 err = -EINVAL;
2236 break;
2237 }
2238 tp->rx_opt.user_mss = val;
2239 break;
2240
2241 case TCP_NODELAY:
2242 if (val) {
2243 /* TCP_NODELAY is weaker than TCP_CORK, so that
2244 * this option on corked socket is remembered, but
2245 * it is not activated until cork is cleared.
2246 *
2247 * However, when TCP_NODELAY is set we make
2248 * an explicit push, which overrides even TCP_CORK
2249 * for currently queued segments.
2250 */
2251 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2252 tcp_push_pending_frames(sk);
2253 } else {
2254 tp->nonagle &= ~TCP_NAGLE_OFF;
2255 }
2256 break;
2257
2258 case TCP_THIN_LINEAR_TIMEOUTS:
2259 if (val < 0 || val > 1)
2260 err = -EINVAL;
2261 else
2262 tp->thin_lto = val;
2263 break;
2264
2265 case TCP_THIN_DUPACK:
2266 if (val < 0 || val > 1)
2267 err = -EINVAL;
2268 else
2269 tp->thin_dupack = val;
2270 break;
2271
2272 case TCP_CORK:
2273 /* When set indicates to always queue non-full frames.
2274 * Later the user clears this option and we transmit
2275 * any pending partial frames in the queue. This is
2276 * meant to be used alongside sendfile() to get properly
2277 * filled frames when the user (for example) must write
2278 * out headers with a write() call first and then use
2279 * sendfile to send out the data parts.
2280 *
2281 * TCP_CORK can be set together with TCP_NODELAY and it is
2282 * stronger than TCP_NODELAY.
2283 */
2284 if (val) {
2285 tp->nonagle |= TCP_NAGLE_CORK;
2286 } else {
2287 tp->nonagle &= ~TCP_NAGLE_CORK;
2288 if (tp->nonagle&TCP_NAGLE_OFF)
2289 tp->nonagle |= TCP_NAGLE_PUSH;
2290 tcp_push_pending_frames(sk);
2291 }
2292 break;
2293
2294 case TCP_KEEPIDLE:
2295 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2296 err = -EINVAL;
2297 else {
2298 tp->keepalive_time = val * HZ;
2299 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2300 !((1 << sk->sk_state) &
2301 (TCPF_CLOSE | TCPF_LISTEN))) {
2302 u32 elapsed = keepalive_time_elapsed(tp);
2303 if (tp->keepalive_time > elapsed)
2304 elapsed = tp->keepalive_time - elapsed;
2305 else
2306 elapsed = 0;
2307 inet_csk_reset_keepalive_timer(sk, elapsed);
2308 }
2309 }
2310 break;
2311 case TCP_KEEPINTVL:
2312 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2313 err = -EINVAL;
2314 else
2315 tp->keepalive_intvl = val * HZ;
2316 break;
2317 case TCP_KEEPCNT:
2318 if (val < 1 || val > MAX_TCP_KEEPCNT)
2319 err = -EINVAL;
2320 else
2321 tp->keepalive_probes = val;
2322 break;
2323 case TCP_SYNCNT:
2324 if (val < 1 || val > MAX_TCP_SYNCNT)
2325 err = -EINVAL;
2326 else
2327 icsk->icsk_syn_retries = val;
2328 break;
2329
2330 case TCP_LINGER2:
2331 if (val < 0)
2332 tp->linger2 = -1;
2333 else if (val > sysctl_tcp_fin_timeout / HZ)
2334 tp->linger2 = 0;
2335 else
2336 tp->linger2 = val * HZ;
2337 break;
2338
2339 case TCP_DEFER_ACCEPT:
2340 /* Translate value in seconds to number of retransmits */
2341 icsk->icsk_accept_queue.rskq_defer_accept =
2342 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2343 TCP_RTO_MAX / HZ);
2344 break;
2345
2346 case TCP_WINDOW_CLAMP:
2347 if (!val) {
2348 if (sk->sk_state != TCP_CLOSE) {
2349 err = -EINVAL;
2350 break;
2351 }
2352 tp->window_clamp = 0;
2353 } else
2354 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2355 SOCK_MIN_RCVBUF / 2 : val;
2356 break;
2357
2358 case TCP_QUICKACK:
2359 if (!val) {
2360 icsk->icsk_ack.pingpong = 1;
2361 } else {
2362 icsk->icsk_ack.pingpong = 0;
2363 if ((1 << sk->sk_state) &
2364 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2365 inet_csk_ack_scheduled(sk)) {
2366 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2367 tcp_cleanup_rbuf(sk, 1);
2368 if (!(val & 1))
2369 icsk->icsk_ack.pingpong = 1;
2370 }
2371 }
2372 break;
2373
2374 #ifdef CONFIG_TCP_MD5SIG
2375 case TCP_MD5SIG:
2376 /* Read the IP->Key mappings from userspace */
2377 err = tp->af_specific->md5_parse(sk, optval, optlen);
2378 break;
2379 #endif
2380
2381 default:
2382 err = -ENOPROTOOPT;
2383 break;
2384 }
2385
2386 release_sock(sk);
2387 return err;
2388 }
2389
2390 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2391 unsigned int optlen)
2392 {
2393 struct inet_connection_sock *icsk = inet_csk(sk);
2394
2395 if (level != SOL_TCP)
2396 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2397 optval, optlen);
2398 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2399 }
2400
2401 #ifdef CONFIG_COMPAT
2402 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2403 char __user *optval, unsigned int optlen)
2404 {
2405 if (level != SOL_TCP)
2406 return inet_csk_compat_setsockopt(sk, level, optname,
2407 optval, optlen);
2408 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2409 }
2410
2411 EXPORT_SYMBOL(compat_tcp_setsockopt);
2412 #endif
2413
2414 /* Return information about state of tcp endpoint in API format. */
2415 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2416 {
2417 struct tcp_sock *tp = tcp_sk(sk);
2418 const struct inet_connection_sock *icsk = inet_csk(sk);
2419 u32 now = tcp_time_stamp;
2420
2421 memset(info, 0, sizeof(*info));
2422
2423 info->tcpi_state = sk->sk_state;
2424 info->tcpi_ca_state = icsk->icsk_ca_state;
2425 info->tcpi_retransmits = icsk->icsk_retransmits;
2426 info->tcpi_probes = icsk->icsk_probes_out;
2427 info->tcpi_backoff = icsk->icsk_backoff;
2428
2429 if (tp->rx_opt.tstamp_ok)
2430 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2431 if (tcp_is_sack(tp))
2432 info->tcpi_options |= TCPI_OPT_SACK;
2433 if (tp->rx_opt.wscale_ok) {
2434 info->tcpi_options |= TCPI_OPT_WSCALE;
2435 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2436 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2437 }
2438
2439 if (tp->ecn_flags&TCP_ECN_OK)
2440 info->tcpi_options |= TCPI_OPT_ECN;
2441
2442 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2443 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2444 info->tcpi_snd_mss = tp->mss_cache;
2445 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2446
2447 if (sk->sk_state == TCP_LISTEN) {
2448 info->tcpi_unacked = sk->sk_ack_backlog;
2449 info->tcpi_sacked = sk->sk_max_ack_backlog;
2450 } else {
2451 info->tcpi_unacked = tp->packets_out;
2452 info->tcpi_sacked = tp->sacked_out;
2453 }
2454 info->tcpi_lost = tp->lost_out;
2455 info->tcpi_retrans = tp->retrans_out;
2456 info->tcpi_fackets = tp->fackets_out;
2457
2458 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2459 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2460 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2461
2462 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2463 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2464 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2465 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2466 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2467 info->tcpi_snd_cwnd = tp->snd_cwnd;
2468 info->tcpi_advmss = tp->advmss;
2469 info->tcpi_reordering = tp->reordering;
2470
2471 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2472 info->tcpi_rcv_space = tp->rcvq_space.space;
2473
2474 info->tcpi_total_retrans = tp->total_retrans;
2475 }
2476
2477 EXPORT_SYMBOL_GPL(tcp_get_info);
2478
2479 static int do_tcp_getsockopt(struct sock *sk, int level,
2480 int optname, char __user *optval, int __user *optlen)
2481 {
2482 struct inet_connection_sock *icsk = inet_csk(sk);
2483 struct tcp_sock *tp = tcp_sk(sk);
2484 int val, len;
2485
2486 if (get_user(len, optlen))
2487 return -EFAULT;
2488
2489 len = min_t(unsigned int, len, sizeof(int));
2490
2491 if (len < 0)
2492 return -EINVAL;
2493
2494 switch (optname) {
2495 case TCP_MAXSEG:
2496 val = tp->mss_cache;
2497 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2498 val = tp->rx_opt.user_mss;
2499 break;
2500 case TCP_NODELAY:
2501 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2502 break;
2503 case TCP_CORK:
2504 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2505 break;
2506 case TCP_KEEPIDLE:
2507 val = keepalive_time_when(tp) / HZ;
2508 break;
2509 case TCP_KEEPINTVL:
2510 val = keepalive_intvl_when(tp) / HZ;
2511 break;
2512 case TCP_KEEPCNT:
2513 val = keepalive_probes(tp);
2514 break;
2515 case TCP_SYNCNT:
2516 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2517 break;
2518 case TCP_LINGER2:
2519 val = tp->linger2;
2520 if (val >= 0)
2521 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2522 break;
2523 case TCP_DEFER_ACCEPT:
2524 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2525 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2526 break;
2527 case TCP_WINDOW_CLAMP:
2528 val = tp->window_clamp;
2529 break;
2530 case TCP_INFO: {
2531 struct tcp_info info;
2532
2533 if (get_user(len, optlen))
2534 return -EFAULT;
2535
2536 tcp_get_info(sk, &info);
2537
2538 len = min_t(unsigned int, len, sizeof(info));
2539 if (put_user(len, optlen))
2540 return -EFAULT;
2541 if (copy_to_user(optval, &info, len))
2542 return -EFAULT;
2543 return 0;
2544 }
2545 case TCP_QUICKACK:
2546 val = !icsk->icsk_ack.pingpong;
2547 break;
2548
2549 case TCP_CONGESTION:
2550 if (get_user(len, optlen))
2551 return -EFAULT;
2552 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2553 if (put_user(len, optlen))
2554 return -EFAULT;
2555 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2556 return -EFAULT;
2557 return 0;
2558
2559 case TCP_COOKIE_TRANSACTIONS: {
2560 struct tcp_cookie_transactions ctd;
2561 struct tcp_cookie_values *cvp = tp->cookie_values;
2562
2563 if (get_user(len, optlen))
2564 return -EFAULT;
2565 if (len < sizeof(ctd))
2566 return -EINVAL;
2567
2568 memset(&ctd, 0, sizeof(ctd));
2569 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2570 TCP_COOKIE_IN_ALWAYS : 0)
2571 | (tp->rx_opt.cookie_out_never ?
2572 TCP_COOKIE_OUT_NEVER : 0);
2573
2574 if (cvp != NULL) {
2575 ctd.tcpct_flags |= (cvp->s_data_in ?
2576 TCP_S_DATA_IN : 0)
2577 | (cvp->s_data_out ?
2578 TCP_S_DATA_OUT : 0);
2579
2580 ctd.tcpct_cookie_desired = cvp->cookie_desired;
2581 ctd.tcpct_s_data_desired = cvp->s_data_desired;
2582
2583 memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2584 cvp->cookie_pair_size);
2585 ctd.tcpct_used = cvp->cookie_pair_size;
2586 }
2587
2588 if (put_user(sizeof(ctd), optlen))
2589 return -EFAULT;
2590 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2591 return -EFAULT;
2592 return 0;
2593 }
2594 default:
2595 return -ENOPROTOOPT;
2596 }
2597
2598 if (put_user(len, optlen))
2599 return -EFAULT;
2600 if (copy_to_user(optval, &val, len))
2601 return -EFAULT;
2602 return 0;
2603 }
2604
2605 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2606 int __user *optlen)
2607 {
2608 struct inet_connection_sock *icsk = inet_csk(sk);
2609
2610 if (level != SOL_TCP)
2611 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2612 optval, optlen);
2613 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2614 }
2615
2616 #ifdef CONFIG_COMPAT
2617 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2618 char __user *optval, int __user *optlen)
2619 {
2620 if (level != SOL_TCP)
2621 return inet_csk_compat_getsockopt(sk, level, optname,
2622 optval, optlen);
2623 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2624 }
2625
2626 EXPORT_SYMBOL(compat_tcp_getsockopt);
2627 #endif
2628
2629 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2630 {
2631 struct sk_buff *segs = ERR_PTR(-EINVAL);
2632 struct tcphdr *th;
2633 unsigned thlen;
2634 unsigned int seq;
2635 __be32 delta;
2636 unsigned int oldlen;
2637 unsigned int mss;
2638
2639 if (!pskb_may_pull(skb, sizeof(*th)))
2640 goto out;
2641
2642 th = tcp_hdr(skb);
2643 thlen = th->doff * 4;
2644 if (thlen < sizeof(*th))
2645 goto out;
2646
2647 if (!pskb_may_pull(skb, thlen))
2648 goto out;
2649
2650 oldlen = (u16)~skb->len;
2651 __skb_pull(skb, thlen);
2652
2653 mss = skb_shinfo(skb)->gso_size;
2654 if (unlikely(skb->len <= mss))
2655 goto out;
2656
2657 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2658 /* Packet is from an untrusted source, reset gso_segs. */
2659 int type = skb_shinfo(skb)->gso_type;
2660
2661 if (unlikely(type &
2662 ~(SKB_GSO_TCPV4 |
2663 SKB_GSO_DODGY |
2664 SKB_GSO_TCP_ECN |
2665 SKB_GSO_TCPV6 |
2666 0) ||
2667 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2668 goto out;
2669
2670 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2671
2672 segs = NULL;
2673 goto out;
2674 }
2675
2676 segs = skb_segment(skb, features);
2677 if (IS_ERR(segs))
2678 goto out;
2679
2680 delta = htonl(oldlen + (thlen + mss));
2681
2682 skb = segs;
2683 th = tcp_hdr(skb);
2684 seq = ntohl(th->seq);
2685
2686 do {
2687 th->fin = th->psh = 0;
2688
2689 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2690 (__force u32)delta));
2691 if (skb->ip_summed != CHECKSUM_PARTIAL)
2692 th->check =
2693 csum_fold(csum_partial(skb_transport_header(skb),
2694 thlen, skb->csum));
2695
2696 seq += mss;
2697 skb = skb->next;
2698 th = tcp_hdr(skb);
2699
2700 th->seq = htonl(seq);
2701 th->cwr = 0;
2702 } while (skb->next);
2703
2704 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2705 skb->data_len);
2706 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2707 (__force u32)delta));
2708 if (skb->ip_summed != CHECKSUM_PARTIAL)
2709 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2710 thlen, skb->csum));
2711
2712 out:
2713 return segs;
2714 }
2715 EXPORT_SYMBOL(tcp_tso_segment);
2716
2717 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2718 {
2719 struct sk_buff **pp = NULL;
2720 struct sk_buff *p;
2721 struct tcphdr *th;
2722 struct tcphdr *th2;
2723 unsigned int len;
2724 unsigned int thlen;
2725 __be32 flags;
2726 unsigned int mss = 1;
2727 unsigned int hlen;
2728 unsigned int off;
2729 int flush = 1;
2730 int i;
2731
2732 off = skb_gro_offset(skb);
2733 hlen = off + sizeof(*th);
2734 th = skb_gro_header_fast(skb, off);
2735 if (skb_gro_header_hard(skb, hlen)) {
2736 th = skb_gro_header_slow(skb, hlen, off);
2737 if (unlikely(!th))
2738 goto out;
2739 }
2740
2741 thlen = th->doff * 4;
2742 if (thlen < sizeof(*th))
2743 goto out;
2744
2745 hlen = off + thlen;
2746 if (skb_gro_header_hard(skb, hlen)) {
2747 th = skb_gro_header_slow(skb, hlen, off);
2748 if (unlikely(!th))
2749 goto out;
2750 }
2751
2752 skb_gro_pull(skb, thlen);
2753
2754 len = skb_gro_len(skb);
2755 flags = tcp_flag_word(th);
2756
2757 for (; (p = *head); head = &p->next) {
2758 if (!NAPI_GRO_CB(p)->same_flow)
2759 continue;
2760
2761 th2 = tcp_hdr(p);
2762
2763 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2764 NAPI_GRO_CB(p)->same_flow = 0;
2765 continue;
2766 }
2767
2768 goto found;
2769 }
2770
2771 goto out_check_final;
2772
2773 found:
2774 flush = NAPI_GRO_CB(p)->flush;
2775 flush |= (__force int)(flags & TCP_FLAG_CWR);
2776 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
2777 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
2778 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
2779 for (i = sizeof(*th); i < thlen; i += 4)
2780 flush |= *(u32 *)((u8 *)th + i) ^
2781 *(u32 *)((u8 *)th2 + i);
2782
2783 mss = skb_shinfo(p)->gso_size;
2784
2785 flush |= (len - 1) >= mss;
2786 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2787
2788 if (flush || skb_gro_receive(head, skb)) {
2789 mss = 1;
2790 goto out_check_final;
2791 }
2792
2793 p = *head;
2794 th2 = tcp_hdr(p);
2795 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2796
2797 out_check_final:
2798 flush = len < mss;
2799 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
2800 TCP_FLAG_RST | TCP_FLAG_SYN |
2801 TCP_FLAG_FIN));
2802
2803 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2804 pp = head;
2805
2806 out:
2807 NAPI_GRO_CB(skb)->flush |= flush;
2808
2809 return pp;
2810 }
2811 EXPORT_SYMBOL(tcp_gro_receive);
2812
2813 int tcp_gro_complete(struct sk_buff *skb)
2814 {
2815 struct tcphdr *th = tcp_hdr(skb);
2816
2817 skb->csum_start = skb_transport_header(skb) - skb->head;
2818 skb->csum_offset = offsetof(struct tcphdr, check);
2819 skb->ip_summed = CHECKSUM_PARTIAL;
2820
2821 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2822
2823 if (th->cwr)
2824 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2825
2826 return 0;
2827 }
2828 EXPORT_SYMBOL(tcp_gro_complete);
2829
2830 #ifdef CONFIG_TCP_MD5SIG
2831 static unsigned long tcp_md5sig_users;
2832 static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool;
2833 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2834
2835 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool)
2836 {
2837 int cpu;
2838 for_each_possible_cpu(cpu) {
2839 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2840 if (p) {
2841 if (p->md5_desc.tfm)
2842 crypto_free_hash(p->md5_desc.tfm);
2843 kfree(p);
2844 }
2845 }
2846 free_percpu(pool);
2847 }
2848
2849 void tcp_free_md5sig_pool(void)
2850 {
2851 struct tcp_md5sig_pool * __percpu *pool = NULL;
2852
2853 spin_lock_bh(&tcp_md5sig_pool_lock);
2854 if (--tcp_md5sig_users == 0) {
2855 pool = tcp_md5sig_pool;
2856 tcp_md5sig_pool = NULL;
2857 }
2858 spin_unlock_bh(&tcp_md5sig_pool_lock);
2859 if (pool)
2860 __tcp_free_md5sig_pool(pool);
2861 }
2862
2863 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2864
2865 static struct tcp_md5sig_pool * __percpu *
2866 __tcp_alloc_md5sig_pool(struct sock *sk)
2867 {
2868 int cpu;
2869 struct tcp_md5sig_pool * __percpu *pool;
2870
2871 pool = alloc_percpu(struct tcp_md5sig_pool *);
2872 if (!pool)
2873 return NULL;
2874
2875 for_each_possible_cpu(cpu) {
2876 struct tcp_md5sig_pool *p;
2877 struct crypto_hash *hash;
2878
2879 p = kzalloc(sizeof(*p), sk->sk_allocation);
2880 if (!p)
2881 goto out_free;
2882 *per_cpu_ptr(pool, cpu) = p;
2883
2884 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2885 if (!hash || IS_ERR(hash))
2886 goto out_free;
2887
2888 p->md5_desc.tfm = hash;
2889 }
2890 return pool;
2891 out_free:
2892 __tcp_free_md5sig_pool(pool);
2893 return NULL;
2894 }
2895
2896 struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
2897 {
2898 struct tcp_md5sig_pool * __percpu *pool;
2899 int alloc = 0;
2900
2901 retry:
2902 spin_lock_bh(&tcp_md5sig_pool_lock);
2903 pool = tcp_md5sig_pool;
2904 if (tcp_md5sig_users++ == 0) {
2905 alloc = 1;
2906 spin_unlock_bh(&tcp_md5sig_pool_lock);
2907 } else if (!pool) {
2908 tcp_md5sig_users--;
2909 spin_unlock_bh(&tcp_md5sig_pool_lock);
2910 cpu_relax();
2911 goto retry;
2912 } else
2913 spin_unlock_bh(&tcp_md5sig_pool_lock);
2914
2915 if (alloc) {
2916 /* we cannot hold spinlock here because this may sleep. */
2917 struct tcp_md5sig_pool * __percpu *p;
2918
2919 p = __tcp_alloc_md5sig_pool(sk);
2920 spin_lock_bh(&tcp_md5sig_pool_lock);
2921 if (!p) {
2922 tcp_md5sig_users--;
2923 spin_unlock_bh(&tcp_md5sig_pool_lock);
2924 return NULL;
2925 }
2926 pool = tcp_md5sig_pool;
2927 if (pool) {
2928 /* oops, it has already been assigned. */
2929 spin_unlock_bh(&tcp_md5sig_pool_lock);
2930 __tcp_free_md5sig_pool(p);
2931 } else {
2932 tcp_md5sig_pool = pool = p;
2933 spin_unlock_bh(&tcp_md5sig_pool_lock);
2934 }
2935 }
2936 return pool;
2937 }
2938
2939 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2940
2941
2942 /**
2943 * tcp_get_md5sig_pool - get md5sig_pool for this user
2944 *
2945 * We use percpu structure, so if we succeed, we exit with preemption
2946 * and BH disabled, to make sure another thread or softirq handling
2947 * wont try to get same context.
2948 */
2949 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2950 {
2951 struct tcp_md5sig_pool * __percpu *p;
2952
2953 local_bh_disable();
2954
2955 spin_lock(&tcp_md5sig_pool_lock);
2956 p = tcp_md5sig_pool;
2957 if (p)
2958 tcp_md5sig_users++;
2959 spin_unlock(&tcp_md5sig_pool_lock);
2960
2961 if (p)
2962 return *per_cpu_ptr(p, smp_processor_id());
2963
2964 local_bh_enable();
2965 return NULL;
2966 }
2967 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2968
2969 void tcp_put_md5sig_pool(void)
2970 {
2971 local_bh_enable();
2972 tcp_free_md5sig_pool();
2973 }
2974 EXPORT_SYMBOL(tcp_put_md5sig_pool);
2975
2976 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2977 struct tcphdr *th)
2978 {
2979 struct scatterlist sg;
2980 int err;
2981
2982 __sum16 old_checksum = th->check;
2983 th->check = 0;
2984 /* options aren't included in the hash */
2985 sg_init_one(&sg, th, sizeof(struct tcphdr));
2986 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
2987 th->check = old_checksum;
2988 return err;
2989 }
2990
2991 EXPORT_SYMBOL(tcp_md5_hash_header);
2992
2993 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2994 struct sk_buff *skb, unsigned header_len)
2995 {
2996 struct scatterlist sg;
2997 const struct tcphdr *tp = tcp_hdr(skb);
2998 struct hash_desc *desc = &hp->md5_desc;
2999 unsigned i;
3000 const unsigned head_data_len = skb_headlen(skb) > header_len ?
3001 skb_headlen(skb) - header_len : 0;
3002 const struct skb_shared_info *shi = skb_shinfo(skb);
3003
3004 sg_init_table(&sg, 1);
3005
3006 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3007 if (crypto_hash_update(desc, &sg, head_data_len))
3008 return 1;
3009
3010 for (i = 0; i < shi->nr_frags; ++i) {
3011 const struct skb_frag_struct *f = &shi->frags[i];
3012 sg_set_page(&sg, f->page, f->size, f->page_offset);
3013 if (crypto_hash_update(desc, &sg, f->size))
3014 return 1;
3015 }
3016
3017 return 0;
3018 }
3019
3020 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3021
3022 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
3023 {
3024 struct scatterlist sg;
3025
3026 sg_init_one(&sg, key->key, key->keylen);
3027 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3028 }
3029
3030 EXPORT_SYMBOL(tcp_md5_hash_key);
3031
3032 #endif
3033
3034 /**
3035 * Each Responder maintains up to two secret values concurrently for
3036 * efficient secret rollover. Each secret value has 4 states:
3037 *
3038 * Generating. (tcp_secret_generating != tcp_secret_primary)
3039 * Generates new Responder-Cookies, but not yet used for primary
3040 * verification. This is a short-term state, typically lasting only
3041 * one round trip time (RTT).
3042 *
3043 * Primary. (tcp_secret_generating == tcp_secret_primary)
3044 * Used both for generation and primary verification.
3045 *
3046 * Retiring. (tcp_secret_retiring != tcp_secret_secondary)
3047 * Used for verification, until the first failure that can be
3048 * verified by the newer Generating secret. At that time, this
3049 * cookie's state is changed to Secondary, and the Generating
3050 * cookie's state is changed to Primary. This is a short-term state,
3051 * typically lasting only one round trip time (RTT).
3052 *
3053 * Secondary. (tcp_secret_retiring == tcp_secret_secondary)
3054 * Used for secondary verification, after primary verification
3055 * failures. This state lasts no more than twice the Maximum Segment
3056 * Lifetime (2MSL). Then, the secret is discarded.
3057 */
3058 struct tcp_cookie_secret {
3059 /* The secret is divided into two parts. The digest part is the
3060 * equivalent of previously hashing a secret and saving the state,
3061 * and serves as an initialization vector (IV). The message part
3062 * serves as the trailing secret.
3063 */
3064 u32 secrets[COOKIE_WORKSPACE_WORDS];
3065 unsigned long expires;
3066 };
3067
3068 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3069 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3070 #define TCP_SECRET_LIFE (HZ * 600)
3071
3072 static struct tcp_cookie_secret tcp_secret_one;
3073 static struct tcp_cookie_secret tcp_secret_two;
3074
3075 /* Essentially a circular list, without dynamic allocation. */
3076 static struct tcp_cookie_secret *tcp_secret_generating;
3077 static struct tcp_cookie_secret *tcp_secret_primary;
3078 static struct tcp_cookie_secret *tcp_secret_retiring;
3079 static struct tcp_cookie_secret *tcp_secret_secondary;
3080
3081 static DEFINE_SPINLOCK(tcp_secret_locker);
3082
3083 /* Select a pseudo-random word in the cookie workspace.
3084 */
3085 static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3086 {
3087 return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3088 }
3089
3090 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3091 * Called in softirq context.
3092 * Returns: 0 for success.
3093 */
3094 int tcp_cookie_generator(u32 *bakery)
3095 {
3096 unsigned long jiffy = jiffies;
3097
3098 if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3099 spin_lock_bh(&tcp_secret_locker);
3100 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3101 /* refreshed by another */
3102 memcpy(bakery,
3103 &tcp_secret_generating->secrets[0],
3104 COOKIE_WORKSPACE_WORDS);
3105 } else {
3106 /* still needs refreshing */
3107 get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3108
3109 /* The first time, paranoia assumes that the
3110 * randomization function isn't as strong. But,
3111 * this secret initialization is delayed until
3112 * the last possible moment (packet arrival).
3113 * Although that time is observable, it is
3114 * unpredictably variable. Mash in the most
3115 * volatile clock bits available, and expire the
3116 * secret extra quickly.
3117 */
3118 if (unlikely(tcp_secret_primary->expires ==
3119 tcp_secret_secondary->expires)) {
3120 struct timespec tv;
3121
3122 getnstimeofday(&tv);
3123 bakery[COOKIE_DIGEST_WORDS+0] ^=
3124 (u32)tv.tv_nsec;
3125
3126 tcp_secret_secondary->expires = jiffy
3127 + TCP_SECRET_1MSL
3128 + (0x0f & tcp_cookie_work(bakery, 0));
3129 } else {
3130 tcp_secret_secondary->expires = jiffy
3131 + TCP_SECRET_LIFE
3132 + (0xff & tcp_cookie_work(bakery, 1));
3133 tcp_secret_primary->expires = jiffy
3134 + TCP_SECRET_2MSL
3135 + (0x1f & tcp_cookie_work(bakery, 2));
3136 }
3137 memcpy(&tcp_secret_secondary->secrets[0],
3138 bakery, COOKIE_WORKSPACE_WORDS);
3139
3140 rcu_assign_pointer(tcp_secret_generating,
3141 tcp_secret_secondary);
3142 rcu_assign_pointer(tcp_secret_retiring,
3143 tcp_secret_primary);
3144 /*
3145 * Neither call_rcu() nor synchronize_rcu() needed.
3146 * Retiring data is not freed. It is replaced after
3147 * further (locked) pointer updates, and a quiet time
3148 * (minimum 1MSL, maximum LIFE - 2MSL).
3149 */
3150 }
3151 spin_unlock_bh(&tcp_secret_locker);
3152 } else {
3153 rcu_read_lock_bh();
3154 memcpy(bakery,
3155 &rcu_dereference(tcp_secret_generating)->secrets[0],
3156 COOKIE_WORKSPACE_WORDS);
3157 rcu_read_unlock_bh();
3158 }
3159 return 0;
3160 }
3161 EXPORT_SYMBOL(tcp_cookie_generator);
3162
3163 void tcp_done(struct sock *sk)
3164 {
3165 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3166 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3167
3168 tcp_set_state(sk, TCP_CLOSE);
3169 tcp_clear_xmit_timers(sk);
3170
3171 sk->sk_shutdown = SHUTDOWN_MASK;
3172
3173 if (!sock_flag(sk, SOCK_DEAD))
3174 sk->sk_state_change(sk);
3175 else
3176 inet_csk_destroy_sock(sk);
3177 }
3178 EXPORT_SYMBOL_GPL(tcp_done);
3179
3180 extern struct tcp_congestion_ops tcp_reno;
3181
3182 static __initdata unsigned long thash_entries;
3183 static int __init set_thash_entries(char *str)
3184 {
3185 if (!str)
3186 return 0;
3187 thash_entries = simple_strtoul(str, &str, 0);
3188 return 1;
3189 }
3190 __setup("thash_entries=", set_thash_entries);
3191
3192 void __init tcp_init(void)
3193 {
3194 struct sk_buff *skb = NULL;
3195 unsigned long nr_pages, limit;
3196 int order, i, max_share;
3197 unsigned long jiffy = jiffies;
3198
3199 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3200
3201 percpu_counter_init(&tcp_sockets_allocated, 0);
3202 percpu_counter_init(&tcp_orphan_count, 0);
3203 tcp_hashinfo.bind_bucket_cachep =
3204 kmem_cache_create("tcp_bind_bucket",
3205 sizeof(struct inet_bind_bucket), 0,
3206 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3207
3208 /* Size and allocate the main established and bind bucket
3209 * hash tables.
3210 *
3211 * The methodology is similar to that of the buffer cache.
3212 */
3213 tcp_hashinfo.ehash =
3214 alloc_large_system_hash("TCP established",
3215 sizeof(struct inet_ehash_bucket),
3216 thash_entries,
3217 (totalram_pages >= 128 * 1024) ?
3218 13 : 15,
3219 0,
3220 NULL,
3221 &tcp_hashinfo.ehash_mask,
3222 thash_entries ? 0 : 512 * 1024);
3223 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3224 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3225 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3226 }
3227 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3228 panic("TCP: failed to alloc ehash_locks");
3229 tcp_hashinfo.bhash =
3230 alloc_large_system_hash("TCP bind",
3231 sizeof(struct inet_bind_hashbucket),
3232 tcp_hashinfo.ehash_mask + 1,
3233 (totalram_pages >= 128 * 1024) ?
3234 13 : 15,
3235 0,
3236 &tcp_hashinfo.bhash_size,
3237 NULL,
3238 64 * 1024);
3239 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
3240 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3241 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3242 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3243 }
3244
3245 /* Try to be a bit smarter and adjust defaults depending
3246 * on available memory.
3247 */
3248 for (order = 0; ((1 << order) << PAGE_SHIFT) <
3249 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
3250 order++)
3251 ;
3252 if (order >= 4) {
3253 tcp_death_row.sysctl_max_tw_buckets = 180000;
3254 sysctl_tcp_max_orphans = 4096 << (order - 4);
3255 sysctl_max_syn_backlog = 1024;
3256 } else if (order < 3) {
3257 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
3258 sysctl_tcp_max_orphans >>= (3 - order);
3259 sysctl_max_syn_backlog = 128;
3260 }
3261
3262 /* Set the pressure threshold to be a fraction of global memory that
3263 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
3264 * memory, with a floor of 128 pages.
3265 */
3266 nr_pages = totalram_pages - totalhigh_pages;
3267 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
3268 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
3269 limit = max(limit, 128UL);
3270 sysctl_tcp_mem[0] = limit / 4 * 3;
3271 sysctl_tcp_mem[1] = limit;
3272 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3273
3274 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3275 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
3276 max_share = min(4UL*1024*1024, limit);
3277
3278 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3279 sysctl_tcp_wmem[1] = 16*1024;
3280 sysctl_tcp_wmem[2] = max(64*1024, max_share);
3281
3282 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3283 sysctl_tcp_rmem[1] = 87380;
3284 sysctl_tcp_rmem[2] = max(87380, max_share);
3285
3286 printk(KERN_INFO "TCP: Hash tables configured "
3287 "(established %u bind %u)\n",
3288 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3289
3290 tcp_register_congestion_control(&tcp_reno);
3291
3292 memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3293 memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3294 tcp_secret_one.expires = jiffy; /* past due */
3295 tcp_secret_two.expires = jiffy; /* past due */
3296 tcp_secret_generating = &tcp_secret_one;
3297 tcp_secret_primary = &tcp_secret_one;
3298 tcp_secret_retiring = &tcp_secret_two;
3299 tcp_secret_secondary = &tcp_secret_two;
3300 }
3301
3302 EXPORT_SYMBOL(tcp_close);
3303 EXPORT_SYMBOL(tcp_disconnect);
3304 EXPORT_SYMBOL(tcp_getsockopt);
3305 EXPORT_SYMBOL(tcp_ioctl);
3306 EXPORT_SYMBOL(tcp_poll);
3307 EXPORT_SYMBOL(tcp_read_sock);
3308 EXPORT_SYMBOL(tcp_recvmsg);
3309 EXPORT_SYMBOL(tcp_sendmsg);
3310 EXPORT_SYMBOL(tcp_splice_read);
3311 EXPORT_SYMBOL(tcp_sendpage);
3312 EXPORT_SYMBOL(tcp_setsockopt);
3313 EXPORT_SYMBOL(tcp_shutdown);
Linux kernel - Deliverables
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