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code style scripts/checkpatch.pl (linux-3.9-rc1) formatting
[linux-2.6.34.14-moxart.git] / net / ipv4 / tcp.c
blob3a8cbf72b06eda70adf2ce77b411d651962a0592
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 long 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_long_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->sk_sleep, 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
392 /*
393 * POLLHUP is certainly not done right. But poll() doesn't
394 * have a notion of HUP in just one direction, and for a
395 * socket the read side is more interesting.
396 *
397 * Some poll() documentation says that POLLHUP is incompatible
398 * with the POLLOUT/POLLWR flags, so somebody should check this
399 * all. But careful, it tends to be safer to return too many
400 * bits than too few, and you can easily break real applications
401 * if you don't tell them that something has hung up!
402 *
403 * Check-me.
404 *
405 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
406 * our fs/select.c). It means that after we received EOF,
407 * poll always returns immediately, making impossible poll() on write()
408 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
409 * if and only if shutdown has been made in both directions.
410 * Actually, it is interesting to look how Solaris and DUX
411 * solve this dilemma. I would prefer, if POLLHUP were maskable,
412 * then we could set it on SND_SHUTDOWN. BTW examples given
413 * in Stevens' books assume exactly this behaviour, it explains
414 * why POLLHUP is incompatible with POLLOUT. --ANK
415 *
416 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
417 * blocking on fresh not-connected or disconnected socket. --ANK
418 */
419 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
420 mask |= POLLHUP;
421 if (sk->sk_shutdown & RCV_SHUTDOWN)
422 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
423
424 /* Connected? */
425 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
426 int target = sock_rcvlowat(sk, 0, INT_MAX);
427
428 if (tp->urg_seq == tp->copied_seq &&
429 !sock_flag(sk, SOCK_URGINLINE) &&
430 tp->urg_data)
431 target++;
432
433 /* Potential race condition. If read of tp below will
434 * escape above sk->sk_state, we can be illegally awaken
435 * in SYN_* states. */
436 if (tp->rcv_nxt - tp->copied_seq >= target)
437 mask |= POLLIN | POLLRDNORM;
438
439 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
440 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
441 mask |= POLLOUT | POLLWRNORM;
442 } else { /* send SIGIO later */
443 set_bit(SOCK_ASYNC_NOSPACE,
444 &sk->sk_socket->flags);
445 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
446
447 /* Race breaker. If space is freed after
448 * wspace test but before the flags are set,
449 * IO signal will be lost.
450 */
451 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
452 mask |= POLLOUT | POLLWRNORM;
453 }
454 } else
455 mask |= POLLOUT | POLLWRNORM;
456
457 if (tp->urg_data & TCP_URG_VALID)
458 mask |= POLLPRI;
459 }
460 /* This barrier is coupled with smp_wmb() in tcp_reset() */
461 smp_rmb();
462 if (sk->sk_err)
463 mask |= POLLERR;
464
465 return mask;
466 }
467
468 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
469 {
470 struct tcp_sock *tp = tcp_sk(sk);
471 int answ;
472
473 switch (cmd) {
474 case SIOCINQ:
475 if (sk->sk_state == TCP_LISTEN)
476 return -EINVAL;
477
478 lock_sock(sk);
479 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
480 answ = 0;
481 else if (sock_flag(sk, SOCK_URGINLINE) ||
482 !tp->urg_data ||
483 before(tp->urg_seq, tp->copied_seq) ||
484 !before(tp->urg_seq, tp->rcv_nxt)) {
485 struct sk_buff *skb;
486
487 answ = tp->rcv_nxt - tp->copied_seq;
488
489 /* Subtract 1, if FIN is in queue. */
490 skb = skb_peek_tail(&sk->sk_receive_queue);
491 if (answ && skb)
492 answ -= tcp_hdr(skb)->fin;
493 } else
494 answ = tp->urg_seq - tp->copied_seq;
495 release_sock(sk);
496 break;
497 case SIOCATMARK:
498 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
499 break;
500 case SIOCOUTQ:
501 if (sk->sk_state == TCP_LISTEN)
502 return -EINVAL;
503
504 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
505 answ = 0;
506 else
507 answ = tp->write_seq - tp->snd_una;
508 break;
509 default:
510 return -ENOIOCTLCMD;
511 }
512
513 return put_user(answ, (int __user *)arg);
514 }
515
516 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
517 {
518 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
519 tp->pushed_seq = tp->write_seq;
520 }
521
522 static inline int forced_push(struct tcp_sock *tp)
523 {
524 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
525 }
526
527 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
528 {
529 struct tcp_sock *tp = tcp_sk(sk);
530 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
531
532 skb->csum = 0;
533 tcb->seq = tcb->end_seq = tp->write_seq;
534 tcb->flags = TCPCB_FLAG_ACK;
535 tcb->sacked = 0;
536 skb_header_release(skb);
537 tcp_add_write_queue_tail(sk, skb);
538 sk->sk_wmem_queued += skb->truesize;
539 sk_mem_charge(sk, skb->truesize);
540 if (tp->nonagle & TCP_NAGLE_PUSH)
541 tp->nonagle &= ~TCP_NAGLE_PUSH;
542 }
543
544 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
545 {
546 if (flags & MSG_OOB)
547 tp->snd_up = tp->write_seq;
548 }
549
550 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
551 int nonagle)
552 {
553 if (tcp_send_head(sk)) {
554 struct tcp_sock *tp = tcp_sk(sk);
555
556 if (!(flags & MSG_MORE) || forced_push(tp))
557 tcp_mark_push(tp, tcp_write_queue_tail(sk));
558
559 tcp_mark_urg(tp, flags);
560 __tcp_push_pending_frames(sk, mss_now,
561 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
562 }
563 }
564
565 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
566 unsigned int offset, size_t len)
567 {
568 struct tcp_splice_state *tss = rd_desc->arg.data;
569 int ret;
570
571 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
572 tss->flags);
573 if (ret > 0)
574 rd_desc->count -= ret;
575 return ret;
576 }
577
578 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
579 {
580 /* Store TCP splice context information in read_descriptor_t. */
581 read_descriptor_t rd_desc = {
582 .arg.data = tss,
583 .count = tss->len,
584 };
585
586 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
587 }
588
589 /**
590 * tcp_splice_read - splice data from TCP socket to a pipe
591 * @sock: socket to splice from
592 * @ppos: position (not valid)
593 * @pipe: pipe to splice to
594 * @len: number of bytes to splice
595 * @flags: splice modifier flags
596 *
597 * Description:
598 * Will read pages from given socket and fill them into a pipe.
599 *
600 **/
601 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
602 struct pipe_inode_info *pipe, size_t len,
603 unsigned int flags)
604 {
605 struct sock *sk = sock->sk;
606 struct tcp_splice_state tss = {
607 .pipe = pipe,
608 .len = len,
609 .flags = flags,
610 };
611 long timeo;
612 ssize_t spliced;
613 int ret;
614
615 /*
616 * We can't seek on a socket input
617 */
618 if (unlikely(*ppos))
619 return -ESPIPE;
620
621 ret = spliced = 0;
622
623 lock_sock(sk);
624
625 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
626 while (tss.len) {
627 ret = __tcp_splice_read(sk, &tss);
628 if (ret < 0)
629 break;
630 else if (!ret) {
631 if (spliced)
632 break;
633 if (sock_flag(sk, SOCK_DONE))
634 break;
635 if (sk->sk_err) {
636 ret = sock_error(sk);
637 break;
638 }
639 if (sk->sk_shutdown & RCV_SHUTDOWN)
640 break;
641 if (sk->sk_state == TCP_CLOSE) {
642 /*
643 * This occurs when user tries to read
644 * from never connected socket.
645 */
646 if (!sock_flag(sk, SOCK_DONE))
647 ret = -ENOTCONN;
648 break;
649 }
650 if (!timeo) {
651 ret = -EAGAIN;
652 break;
653 }
654 sk_wait_data(sk, &timeo);
655 if (signal_pending(current)) {
656 ret = sock_intr_errno(timeo);
657 break;
658 }
659 continue;
660 }
661 tss.len -= ret;
662 spliced += ret;
663
664 if (!timeo)
665 break;
666 release_sock(sk);
667 lock_sock(sk);
668
669 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
670 (sk->sk_shutdown & RCV_SHUTDOWN) ||
671 signal_pending(current))
672 break;
673 }
674
675 release_sock(sk);
676
677 if (spliced)
678 return spliced;
679
680 return ret;
681 }
682
683 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
684 {
685 struct sk_buff *skb;
686
687 /* The TCP header must be at least 32-bit aligned. */
688 size = ALIGN(size, 4);
689
690 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
691 if (skb) {
692 if (sk_wmem_schedule(sk, skb->truesize)) {
693 /*
694 * Make sure that we have exactly size bytes
695 * available to the caller, no more, no less.
696 */
697 skb_reserve(skb, skb_tailroom(skb) - size);
698 return skb;
699 }
700 __kfree_skb(skb);
701 } else {
702 sk->sk_prot->enter_memory_pressure(sk);
703 sk_stream_moderate_sndbuf(sk);
704 }
705 return NULL;
706 }
707
708 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
709 int large_allowed)
710 {
711 struct tcp_sock *tp = tcp_sk(sk);
712 u32 xmit_size_goal, old_size_goal;
713
714 xmit_size_goal = mss_now;
715
716 if (large_allowed && sk_can_gso(sk)) {
717 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
718 inet_csk(sk)->icsk_af_ops->net_header_len -
719 inet_csk(sk)->icsk_ext_hdr_len -
720 tp->tcp_header_len);
721
722 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
723
724 /* We try hard to avoid divides here */
725 old_size_goal = tp->xmit_size_goal_segs * mss_now;
726
727 if (likely(old_size_goal <= xmit_size_goal &&
728 old_size_goal + mss_now > xmit_size_goal)) {
729 xmit_size_goal = old_size_goal;
730 } else {
731 tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
732 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
733 }
734 }
735
736 return max(xmit_size_goal, mss_now);
737 }
738
739 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
740 {
741 int mss_now;
742
743 mss_now = tcp_current_mss(sk);
744 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
745
746 return mss_now;
747 }
748
749 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
750 size_t psize, int flags)
751 {
752 struct tcp_sock *tp = tcp_sk(sk);
753 int mss_now, size_goal;
754 int err;
755 ssize_t copied;
756 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
757
758 /* Wait for a connection to finish. */
759 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
760 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
761 goto out_err;
762
763 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
764
765 mss_now = tcp_send_mss(sk, &size_goal, flags);
766 copied = 0;
767
768 err = -EPIPE;
769 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
770 goto out_err;
771
772 while (psize > 0) {
773 struct sk_buff *skb = tcp_write_queue_tail(sk);
774 struct page *page = pages[poffset / PAGE_SIZE];
775 int copy, i, can_coalesce;
776 int offset = poffset % PAGE_SIZE;
777 int size = min_t(size_t, psize, PAGE_SIZE - offset);
778
779 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
780 new_segment:
781 if (!sk_stream_memory_free(sk))
782 goto wait_for_sndbuf;
783
784 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
785 if (!skb)
786 goto wait_for_memory;
787
788 skb_entail(sk, skb);
789 copy = size_goal;
790 }
791
792 if (copy > size)
793 copy = size;
794
795 i = skb_shinfo(skb)->nr_frags;
796 can_coalesce = skb_can_coalesce(skb, i, page, offset);
797 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
798 tcp_mark_push(tp, skb);
799 goto new_segment;
800 }
801 if (!sk_wmem_schedule(sk, copy))
802 goto wait_for_memory;
803
804 if (can_coalesce) {
805 skb_shinfo(skb)->frags[i - 1].size += copy;
806 } else {
807 get_page(page);
808 skb_fill_page_desc(skb, i, page, offset, copy);
809 }
810
811 skb->len += copy;
812 skb->data_len += copy;
813 skb->truesize += copy;
814 sk->sk_wmem_queued += copy;
815 sk_mem_charge(sk, copy);
816 skb->ip_summed = CHECKSUM_PARTIAL;
817 tp->write_seq += copy;
818 TCP_SKB_CB(skb)->end_seq += copy;
819 skb_shinfo(skb)->gso_segs = 0;
820
821 if (!copied)
822 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
823
824 copied += copy;
825 poffset += copy;
826 if (!(psize -= copy))
827 goto out;
828
829 if (skb->len < size_goal || (flags & MSG_OOB))
830 continue;
831
832 if (forced_push(tp)) {
833 tcp_mark_push(tp, skb);
834 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
835 } else if (skb == tcp_send_head(sk))
836 tcp_push_one(sk, mss_now);
837 continue;
838
839 wait_for_sndbuf:
840 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
841 wait_for_memory:
842 if (copied)
843 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
844
845 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
846 goto do_error;
847
848 mss_now = tcp_send_mss(sk, &size_goal, flags);
849 }
850
851 out:
852 if (copied)
853 tcp_push(sk, flags, mss_now, tp->nonagle);
854 return copied;
855
856 do_error:
857 if (copied)
858 goto out;
859 out_err:
860 return sk_stream_error(sk, flags, err);
861 }
862
863 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
864 size_t size, int flags)
865 {
866 ssize_t res;
867 struct sock *sk = sock->sk;
868
869 if (!(sk->sk_route_caps & NETIF_F_SG) ||
870 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
871 return sock_no_sendpage(sock, page, offset, size, flags);
872
873 lock_sock(sk);
874 TCP_CHECK_TIMER(sk);
875 res = do_tcp_sendpages(sk, &page, offset, size, flags);
876 TCP_CHECK_TIMER(sk);
877 release_sock(sk);
878 return res;
879 }
880
881 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
882 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
883
884 static inline int select_size(struct sock *sk, int sg)
885 {
886 struct tcp_sock *tp = tcp_sk(sk);
887 int tmp = tp->mss_cache;
888
889 if (sg) {
890 if (sk_can_gso(sk))
891 tmp = 0;
892 else {
893 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
894
895 if (tmp >= pgbreak &&
896 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
897 tmp = pgbreak;
898 }
899 }
900
901 return tmp;
902 }
903
904 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
905 size_t size)
906 {
907 struct sock *sk = sock->sk;
908 struct iovec *iov;
909 struct tcp_sock *tp = tcp_sk(sk);
910 struct sk_buff *skb;
911 int iovlen, flags;
912 int mss_now, size_goal;
913 int sg, err, copied;
914 long timeo;
915
916 lock_sock(sk);
917 TCP_CHECK_TIMER(sk);
918
919 flags = msg->msg_flags;
920 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
921
922 /* Wait for a connection to finish. */
923 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
924 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
925 goto out_err;
926
927 /* This should be in poll */
928 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
929
930 mss_now = tcp_send_mss(sk, &size_goal, flags);
931
932 /* Ok commence sending. */
933 iovlen = msg->msg_iovlen;
934 iov = msg->msg_iov;
935 copied = 0;
936
937 err = -EPIPE;
938 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
939 goto out_err;
940
941 sg = sk->sk_route_caps & NETIF_F_SG;
942
943 while (--iovlen >= 0) {
944 size_t seglen = iov->iov_len;
945 unsigned char __user *from = iov->iov_base;
946
947 iov++;
948
949 while (seglen > 0) {
950 int copy = 0;
951 int max = size_goal;
952
953 skb = tcp_write_queue_tail(sk);
954 if (tcp_send_head(sk)) {
955 if (skb->ip_summed == CHECKSUM_NONE)
956 max = mss_now;
957 copy = max - skb->len;
958 }
959
960 if (copy <= 0) {
961 new_segment:
962 /* Allocate new segment. If the interface is SG,
963 * allocate skb fitting to single page.
964 */
965 if (!sk_stream_memory_free(sk))
966 goto wait_for_sndbuf;
967
968 skb = sk_stream_alloc_skb(sk,
969 select_size(sk, sg),
970 sk->sk_allocation);
971 if (!skb)
972 goto wait_for_memory;
973
974 /*
975 * Check whether we can use HW checksum.
976 */
977 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
978 skb->ip_summed = CHECKSUM_PARTIAL;
979
980 skb_entail(sk, skb);
981 copy = size_goal;
982 max = size_goal;
983 }
984
985 /* Try to append data to the end of skb. */
986 if (copy > seglen)
987 copy = seglen;
988
989 /* Where to copy to? */
990 if (skb_tailroom(skb) > 0) {
991 /* We have some space in skb head. Superb! */
992 if (copy > skb_tailroom(skb))
993 copy = skb_tailroom(skb);
994 if ((err = skb_add_data(skb, from, copy)) != 0)
995 goto do_fault;
996 } else {
997 int merge = 0;
998 int i = skb_shinfo(skb)->nr_frags;
999 struct page *page = TCP_PAGE(sk);
1000 int off = TCP_OFF(sk);
1001
1002 if (skb_can_coalesce(skb, i, page, off) &&
1003 off != PAGE_SIZE) {
1004 /* We can extend the last page
1005 * fragment. */
1006 merge = 1;
1007 } else if (i == MAX_SKB_FRAGS || !sg) {
1008 /* Need to add new fragment and cannot
1009 * do this because interface is non-SG,
1010 * or because all the page slots are
1011 * busy. */
1012 tcp_mark_push(tp, skb);
1013 goto new_segment;
1014 } else if (page) {
1015 if (off == PAGE_SIZE) {
1016 put_page(page);
1017 TCP_PAGE(sk) = page = NULL;
1018 off = 0;
1019 }
1020 } else
1021 off = 0;
1022
1023 if (copy > PAGE_SIZE - off)
1024 copy = PAGE_SIZE - off;
1025
1026 if (!sk_wmem_schedule(sk, copy))
1027 goto wait_for_memory;
1028
1029 if (!page) {
1030 /* Allocate new cache page. */
1031 if (!(page = sk_stream_alloc_page(sk)))
1032 goto wait_for_memory;
1033 }
1034
1035 /* Time to copy data. We are close to
1036 * the end! */
1037 err = skb_copy_to_page(sk, from, skb, page,
1038 off, copy);
1039 if (err) {
1040 /* If this page was new, give it to the
1041 * socket so it does not get leaked.
1042 */
1043 if (!TCP_PAGE(sk)) {
1044 TCP_PAGE(sk) = page;
1045 TCP_OFF(sk) = 0;
1046 }
1047 goto do_error;
1048 }
1049
1050 /* Update the skb. */
1051 if (merge) {
1052 skb_shinfo(skb)->frags[i - 1].size +=
1053 copy;
1054 } else {
1055 skb_fill_page_desc(skb, i, page, off, copy);
1056 if (TCP_PAGE(sk)) {
1057 get_page(page);
1058 } else if (off + copy < PAGE_SIZE) {
1059 get_page(page);
1060 TCP_PAGE(sk) = page;
1061 }
1062 }
1063
1064 TCP_OFF(sk) = off + copy;
1065 }
1066
1067 if (!copied)
1068 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
1069
1070 tp->write_seq += copy;
1071 TCP_SKB_CB(skb)->end_seq += copy;
1072 skb_shinfo(skb)->gso_segs = 0;
1073
1074 from += copy;
1075 copied += copy;
1076 if ((seglen -= copy) == 0 && iovlen == 0)
1077 goto out;
1078
1079 if (skb->len < max || (flags & MSG_OOB))
1080 continue;
1081
1082 if (forced_push(tp)) {
1083 tcp_mark_push(tp, skb);
1084 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1085 } else if (skb == tcp_send_head(sk))
1086 tcp_push_one(sk, mss_now);
1087 continue;
1088
1089 wait_for_sndbuf:
1090 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1091 wait_for_memory:
1092 if (copied)
1093 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1094
1095 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1096 goto do_error;
1097
1098 mss_now = tcp_send_mss(sk, &size_goal, flags);
1099 }
1100 }
1101
1102 out:
1103 if (copied)
1104 tcp_push(sk, flags, mss_now, tp->nonagle);
1105 TCP_CHECK_TIMER(sk);
1106 release_sock(sk);
1107 return copied;
1108
1109 do_fault:
1110 if (!skb->len) {
1111 tcp_unlink_write_queue(skb, sk);
1112 /* It is the one place in all of TCP, except connection
1113 * reset, where we can be unlinking the send_head.
1114 */
1115 tcp_check_send_head(sk, skb);
1116 sk_wmem_free_skb(sk, skb);
1117 }
1118
1119 do_error:
1120 if (copied)
1121 goto out;
1122 out_err:
1123 err = sk_stream_error(sk, flags, err);
1124 TCP_CHECK_TIMER(sk);
1125 release_sock(sk);
1126 return err;
1127 }
1128
1129 /*
1130 * Handle reading urgent data. BSD has very simple semantics for
1131 * this, no blocking and very strange errors 8)
1132 */
1133
1134 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1135 {
1136 struct tcp_sock *tp = tcp_sk(sk);
1137
1138 /* No URG data to read. */
1139 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1140 tp->urg_data == TCP_URG_READ)
1141 return -EINVAL; /* Yes this is right ! */
1142
1143 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1144 return -ENOTCONN;
1145
1146 if (tp->urg_data & TCP_URG_VALID) {
1147 int err = 0;
1148 char c = tp->urg_data;
1149
1150 if (!(flags & MSG_PEEK))
1151 tp->urg_data = TCP_URG_READ;
1152
1153 /* Read urgent data. */
1154 msg->msg_flags |= MSG_OOB;
1155
1156 if (len > 0) {
1157 if (!(flags & MSG_TRUNC))
1158 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1159 len = 1;
1160 } else
1161 msg->msg_flags |= MSG_TRUNC;
1162
1163 return err ? -EFAULT : len;
1164 }
1165
1166 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1167 return 0;
1168
1169 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1170 * the available implementations agree in this case:
1171 * this call should never block, independent of the
1172 * blocking state of the socket.
1173 * Mike <pall@rz.uni-karlsruhe.de>
1174 */
1175 return -EAGAIN;
1176 }
1177
1178 /* Clean up the receive buffer for full frames taken by the user,
1179 * then send an ACK if necessary. COPIED is the number of bytes
1180 * tcp_recvmsg has given to the user so far, it speeds up the
1181 * calculation of whether or not we must ACK for the sake of
1182 * a window update.
1183 */
1184 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1185 {
1186 struct tcp_sock *tp = tcp_sk(sk);
1187 int time_to_ack = 0;
1188
1189 #if TCP_DEBUG
1190 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1191
1192 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1193 KERN_INFO "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1194 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1195 #endif
1196
1197 if (inet_csk_ack_scheduled(sk)) {
1198 const struct inet_connection_sock *icsk = inet_csk(sk);
1199 /* Delayed ACKs frequently hit locked sockets during bulk
1200 * receive. */
1201 if (icsk->icsk_ack.blocked ||
1202 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1203 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1204 /*
1205 * If this read emptied read buffer, we send ACK, if
1206 * connection is not bidirectional, user drained
1207 * receive buffer and there was a small segment
1208 * in queue.
1209 */
1210 (copied > 0 &&
1211 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1212 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1213 !icsk->icsk_ack.pingpong)) &&
1214 !atomic_read(&sk->sk_rmem_alloc)))
1215 time_to_ack = 1;
1216 }
1217
1218 /* We send an ACK if we can now advertise a non-zero window
1219 * which has been raised "significantly".
1220 *
1221 * Even if window raised up to infinity, do not send window open ACK
1222 * in states, where we will not receive more. It is useless.
1223 */
1224 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1225 __u32 rcv_window_now = tcp_receive_window(tp);
1226
1227 /* Optimize, __tcp_select_window() is not cheap. */
1228 if (2*rcv_window_now <= tp->window_clamp) {
1229 __u32 new_window = __tcp_select_window(sk);
1230
1231 /* Send ACK now, if this read freed lots of space
1232 * in our buffer. Certainly, new_window is new window.
1233 * We can advertise it now, if it is not less than current one.
1234 * "Lots" means "at least twice" here.
1235 */
1236 if (new_window && new_window >= 2 * rcv_window_now)
1237 time_to_ack = 1;
1238 }
1239 }
1240 if (time_to_ack)
1241 tcp_send_ack(sk);
1242 }
1243
1244 static void tcp_prequeue_process(struct sock *sk)
1245 {
1246 struct sk_buff *skb;
1247 struct tcp_sock *tp = tcp_sk(sk);
1248
1249 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1250
1251 /* RX process wants to run with disabled BHs, though it is not
1252 * necessary */
1253 local_bh_disable();
1254 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1255 sk_backlog_rcv(sk, skb);
1256 local_bh_enable();
1257
1258 /* Clear memory counter. */
1259 tp->ucopy.memory = 0;
1260 }
1261
1262 #ifdef CONFIG_NET_DMA
1263 static void tcp_service_net_dma(struct sock *sk, bool wait)
1264 {
1265 dma_cookie_t done, used;
1266 dma_cookie_t last_issued;
1267 struct tcp_sock *tp = tcp_sk(sk);
1268
1269 if (!tp->ucopy.dma_chan)
1270 return;
1271
1272 last_issued = tp->ucopy.dma_cookie;
1273 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1274
1275 do {
1276 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1277 last_issued, &done,
1278 &used) == DMA_SUCCESS) {
1279 /* Safe to free early-copied skbs now */
1280 __skb_queue_purge(&sk->sk_async_wait_queue);
1281 break;
1282 } else {
1283 struct sk_buff *skb;
1284 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1285 (dma_async_is_complete(skb->dma_cookie, done,
1286 used) == DMA_SUCCESS)) {
1287 __skb_dequeue(&sk->sk_async_wait_queue);
1288 kfree_skb(skb);
1289 }
1290 }
1291 } while (wait);
1292 }
1293 #endif
1294
1295 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1296 {
1297 struct sk_buff *skb;
1298 u32 offset;
1299
1300 skb_queue_walk(&sk->sk_receive_queue, skb) {
1301 offset = seq - TCP_SKB_CB(skb)->seq;
1302 if (tcp_hdr(skb)->syn)
1303 offset--;
1304 if (offset < skb->len || tcp_hdr(skb)->fin) {
1305 *off = offset;
1306 return skb;
1307 }
1308 }
1309 return NULL;
1310 }
1311
1312 /*
1313 * This routine provides an alternative to tcp_recvmsg() for routines
1314 * that would like to handle copying from skbuffs directly in 'sendfile'
1315 * fashion.
1316 * Note:
1317 * - It is assumed that the socket was locked by the caller.
1318 * - The routine does not block.
1319 * - At present, there is no support for reading OOB data
1320 * or for 'peeking' the socket using this routine
1321 * (although both would be easy to implement).
1322 */
1323 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1324 sk_read_actor_t recv_actor)
1325 {
1326 struct sk_buff *skb;
1327 struct tcp_sock *tp = tcp_sk(sk);
1328 u32 seq = tp->copied_seq;
1329 u32 offset;
1330 int copied = 0;
1331
1332 if (sk->sk_state == TCP_LISTEN)
1333 return -ENOTCONN;
1334 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1335 if (offset < skb->len) {
1336 int used;
1337 size_t len;
1338
1339 len = skb->len - offset;
1340 /* Stop reading if we hit a patch of urgent data */
1341 if (tp->urg_data) {
1342 u32 urg_offset = tp->urg_seq - seq;
1343 if (urg_offset < len)
1344 len = urg_offset;
1345 if (!len)
1346 break;
1347 }
1348 used = recv_actor(desc, skb, offset, len);
1349 if (used < 0) {
1350 if (!copied)
1351 copied = used;
1352 break;
1353 } else if (used <= len) {
1354 seq += used;
1355 copied += used;
1356 offset += used;
1357 }
1358 /*
1359 * If recv_actor drops the lock (e.g. TCP splice
1360 * receive) the skb pointer might be invalid when
1361 * getting here: tcp_collapse might have deleted it
1362 * while aggregating skbs from the socket queue.
1363 */
1364 skb = tcp_recv_skb(sk, seq-1, &offset);
1365 if (!skb || (offset+1 != skb->len))
1366 break;
1367 }
1368 if (tcp_hdr(skb)->fin) {
1369 sk_eat_skb(sk, skb, 0);
1370 ++seq;
1371 break;
1372 }
1373 sk_eat_skb(sk, skb, 0);
1374 if (!desc->count)
1375 break;
1376 tp->copied_seq = seq;
1377 }
1378 tp->copied_seq = seq;
1379
1380 tcp_rcv_space_adjust(sk);
1381
1382 /* Clean up data we have read: This will do ACK frames. */
1383 if (copied > 0)
1384 tcp_cleanup_rbuf(sk, copied);
1385 return copied;
1386 }
1387
1388 /*
1389 * This routine copies from a sock struct into the user buffer.
1390 *
1391 * Technical note: in 2.3 we work on _locked_ socket, so that
1392 * tricks with *seq access order and skb->users are not required.
1393 * Probably, code can be easily improved even more.
1394 */
1395
1396 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1397 size_t len, int nonblock, int flags, int *addr_len)
1398 {
1399 struct tcp_sock *tp = tcp_sk(sk);
1400 int copied = 0;
1401 u32 peek_seq;
1402 u32 *seq;
1403 unsigned long used;
1404 int err;
1405 int target; /* Read at least this many bytes */
1406 long timeo;
1407 struct task_struct *user_recv = NULL;
1408 int copied_early = 0;
1409 struct sk_buff *skb;
1410 u32 urg_hole = 0;
1411
1412 lock_sock(sk);
1413
1414 TCP_CHECK_TIMER(sk);
1415
1416 err = -ENOTCONN;
1417 if (sk->sk_state == TCP_LISTEN)
1418 goto out;
1419
1420 timeo = sock_rcvtimeo(sk, nonblock);
1421
1422 /* Urgent data needs to be handled specially. */
1423 if (flags & MSG_OOB)
1424 goto recv_urg;
1425
1426 seq = &tp->copied_seq;
1427 if (flags & MSG_PEEK) {
1428 peek_seq = tp->copied_seq;
1429 seq = &peek_seq;
1430 }
1431
1432 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1433
1434 #ifdef CONFIG_NET_DMA
1435 tp->ucopy.dma_chan = NULL;
1436 preempt_disable();
1437 skb = skb_peek_tail(&sk->sk_receive_queue);
1438 {
1439 int available = 0;
1440
1441 if (skb)
1442 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1443 if ((available < target) &&
1444 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1445 !sysctl_tcp_low_latency &&
1446 dma_find_channel(DMA_MEMCPY)) {
1447 preempt_enable_no_resched();
1448 tp->ucopy.pinned_list =
1449 dma_pin_iovec_pages(msg->msg_iov, len);
1450 } else {
1451 preempt_enable_no_resched();
1452 }
1453 }
1454 #endif
1455
1456 do {
1457 u32 offset;
1458
1459 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1460 if (tp->urg_data && tp->urg_seq == *seq) {
1461 if (copied)
1462 break;
1463 if (signal_pending(current)) {
1464 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1465 break;
1466 }
1467 }
1468
1469 /* Next get a buffer. */
1470
1471 skb_queue_walk(&sk->sk_receive_queue, skb) {
1472 /* Now that we have two receive queues this
1473 * shouldn't happen.
1474 */
1475 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1476 KERN_INFO "recvmsg bug: copied %X "
1477 "seq %X rcvnxt %X fl %X\n", *seq,
1478 TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1479 flags))
1480 break;
1481
1482 offset = *seq - TCP_SKB_CB(skb)->seq;
1483 if (tcp_hdr(skb)->syn)
1484 offset--;
1485 if (offset < skb->len)
1486 goto found_ok_skb;
1487 if (tcp_hdr(skb)->fin)
1488 goto found_fin_ok;
1489 WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "
1490 "copied %X seq %X rcvnxt %X fl %X\n",
1491 *seq, TCP_SKB_CB(skb)->seq,
1492 tp->rcv_nxt, flags);
1493 }
1494
1495 /* Well, if we have backlog, try to process it now yet. */
1496
1497 if (copied >= target && !sk->sk_backlog.tail)
1498 break;
1499
1500 if (copied) {
1501 if (sk->sk_err ||
1502 sk->sk_state == TCP_CLOSE ||
1503 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1504 !timeo ||
1505 signal_pending(current))
1506 break;
1507 } else {
1508 if (sock_flag(sk, SOCK_DONE))
1509 break;
1510
1511 if (sk->sk_err) {
1512 copied = sock_error(sk);
1513 break;
1514 }
1515
1516 if (sk->sk_shutdown & RCV_SHUTDOWN)
1517 break;
1518
1519 if (sk->sk_state == TCP_CLOSE) {
1520 if (!sock_flag(sk, SOCK_DONE)) {
1521 /* This occurs when user tries to read
1522 * from never connected socket.
1523 */
1524 copied = -ENOTCONN;
1525 break;
1526 }
1527 break;
1528 }
1529
1530 if (!timeo) {
1531 copied = -EAGAIN;
1532 break;
1533 }
1534
1535 if (signal_pending(current)) {
1536 copied = sock_intr_errno(timeo);
1537 break;
1538 }
1539 }
1540
1541 tcp_cleanup_rbuf(sk, copied);
1542
1543 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1544 /* Install new reader */
1545 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1546 user_recv = current;
1547 tp->ucopy.task = user_recv;
1548 tp->ucopy.iov = msg->msg_iov;
1549 }
1550
1551 tp->ucopy.len = len;
1552
1553 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1554 !(flags & (MSG_PEEK | MSG_TRUNC)));
1555
1556 /* Ugly... If prequeue is not empty, we have to
1557 * process it before releasing socket, otherwise
1558 * order will be broken at second iteration.
1559 * More elegant solution is required!!!
1560 *
1561 * Look: we have the following (pseudo)queues:
1562 *
1563 * 1. packets in flight
1564 * 2. backlog
1565 * 3. prequeue
1566 * 4. receive_queue
1567 *
1568 * Each queue can be processed only if the next ones
1569 * are empty. At this point we have empty receive_queue.
1570 * But prequeue _can_ be not empty after 2nd iteration,
1571 * when we jumped to start of loop because backlog
1572 * processing added something to receive_queue.
1573 * We cannot release_sock(), because backlog contains
1574 * packets arrived _after_ prequeued ones.
1575 *
1576 * Shortly, algorithm is clear --- to process all
1577 * the queues in order. We could make it more directly,
1578 * requeueing packets from backlog to prequeue, if
1579 * is not empty. It is more elegant, but eats cycles,
1580 * unfortunately.
1581 */
1582 if (!skb_queue_empty(&tp->ucopy.prequeue))
1583 goto do_prequeue;
1584
1585 /* __ Set realtime policy in scheduler __ */
1586 }
1587
1588 #ifdef CONFIG_NET_DMA
1589 if (tp->ucopy.dma_chan)
1590 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1591 #endif
1592 if (copied >= target) {
1593 /* Do not sleep, just process backlog. */
1594 release_sock(sk);
1595 lock_sock(sk);
1596 } else
1597 sk_wait_data(sk, &timeo);
1598
1599 #ifdef CONFIG_NET_DMA
1600 tcp_service_net_dma(sk, false); /* Don't block */
1601 tp->ucopy.wakeup = 0;
1602 #endif
1603
1604 if (user_recv) {
1605 int chunk;
1606
1607 /* __ Restore normal policy in scheduler __ */
1608
1609 if ((chunk = len - tp->ucopy.len) != 0) {
1610 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1611 len -= chunk;
1612 copied += chunk;
1613 }
1614
1615 if (tp->rcv_nxt == tp->copied_seq &&
1616 !skb_queue_empty(&tp->ucopy.prequeue)) {
1617 do_prequeue:
1618 tcp_prequeue_process(sk);
1619
1620 if ((chunk = len - tp->ucopy.len) != 0) {
1621 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1622 len -= chunk;
1623 copied += chunk;
1624 }
1625 }
1626 }
1627 if ((flags & MSG_PEEK) &&
1628 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1629 if (net_ratelimit())
1630 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1631 current->comm, task_pid_nr(current));
1632 peek_seq = tp->copied_seq;
1633 }
1634 continue;
1635
1636 found_ok_skb:
1637 /* Ok so how much can we use? */
1638 used = skb->len - offset;
1639 if (len < used)
1640 used = len;
1641
1642 /* Do we have urgent data here? */
1643 if (tp->urg_data) {
1644 u32 urg_offset = tp->urg_seq - *seq;
1645 if (urg_offset < used) {
1646 if (!urg_offset) {
1647 if (!sock_flag(sk, SOCK_URGINLINE)) {
1648 ++*seq;
1649 urg_hole++;
1650 offset++;
1651 used--;
1652 if (!used)
1653 goto skip_copy;
1654 }
1655 } else
1656 used = urg_offset;
1657 }
1658 }
1659
1660 if (!(flags & MSG_TRUNC)) {
1661 #ifdef CONFIG_NET_DMA
1662 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1663 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1664
1665 if (tp->ucopy.dma_chan) {
1666 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1667 tp->ucopy.dma_chan, skb, offset,
1668 msg->msg_iov, used,
1669 tp->ucopy.pinned_list);
1670
1671 if (tp->ucopy.dma_cookie < 0) {
1672
1673 printk(KERN_ALERT "dma_cookie < 0\n");
1674
1675 /* Exception. Bailout! */
1676 if (!copied)
1677 copied = -EFAULT;
1678 break;
1679 }
1680
1681 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1682
1683 if ((offset + used) == skb->len)
1684 copied_early = 1;
1685
1686 } else
1687 #endif
1688 {
1689 err = skb_copy_datagram_iovec(skb, offset,
1690 msg->msg_iov, used);
1691 if (err) {
1692 /* Exception. Bailout! */
1693 if (!copied)
1694 copied = -EFAULT;
1695 break;
1696 }
1697 }
1698 }
1699
1700 *seq += used;
1701 copied += used;
1702 len -= used;
1703
1704 tcp_rcv_space_adjust(sk);
1705
1706 skip_copy:
1707 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1708 tp->urg_data = 0;
1709 tcp_fast_path_check(sk);
1710 }
1711 if (used + offset < skb->len)
1712 continue;
1713
1714 if (tcp_hdr(skb)->fin)
1715 goto found_fin_ok;
1716 if (!(flags & MSG_PEEK)) {
1717 sk_eat_skb(sk, skb, copied_early);
1718 copied_early = 0;
1719 }
1720 continue;
1721
1722 found_fin_ok:
1723 /* Process the FIN. */
1724 ++*seq;
1725 if (!(flags & MSG_PEEK)) {
1726 sk_eat_skb(sk, skb, copied_early);
1727 copied_early = 0;
1728 }
1729 break;
1730 } while (len > 0);
1731
1732 if (user_recv) {
1733 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1734 int chunk;
1735
1736 tp->ucopy.len = copied > 0 ? len : 0;
1737
1738 tcp_prequeue_process(sk);
1739
1740 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1741 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1742 len -= chunk;
1743 copied += chunk;
1744 }
1745 }
1746
1747 tp->ucopy.task = NULL;
1748 tp->ucopy.len = 0;
1749 }
1750
1751 #ifdef CONFIG_NET_DMA
1752 tcp_service_net_dma(sk, true); /* Wait for queue to drain */
1753 tp->ucopy.dma_chan = NULL;
1754
1755 if (tp->ucopy.pinned_list) {
1756 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1757 tp->ucopy.pinned_list = NULL;
1758 }
1759 #endif
1760
1761 /* According to UNIX98, msg_name/msg_namelen are ignored
1762 * on connected socket. I was just happy when found this 8) --ANK
1763 */
1764
1765 /* Clean up data we have read: This will do ACK frames. */
1766 tcp_cleanup_rbuf(sk, copied);
1767
1768 TCP_CHECK_TIMER(sk);
1769 release_sock(sk);
1770 return copied;
1771
1772 out:
1773 TCP_CHECK_TIMER(sk);
1774 release_sock(sk);
1775 return err;
1776
1777 recv_urg:
1778 err = tcp_recv_urg(sk, msg, len, flags);
1779 goto out;
1780 }
1781
1782 void tcp_set_state(struct sock *sk, int state)
1783 {
1784 int oldstate = sk->sk_state;
1785
1786 switch (state) {
1787 case TCP_ESTABLISHED:
1788 if (oldstate != TCP_ESTABLISHED)
1789 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1790 break;
1791
1792 case TCP_CLOSE:
1793 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1794 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1795
1796 sk->sk_prot->unhash(sk);
1797 if (inet_csk(sk)->icsk_bind_hash &&
1798 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1799 inet_put_port(sk);
1800 /* fall through */
1801 default:
1802 if (oldstate == TCP_ESTABLISHED)
1803 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1804 }
1805
1806 /* Change state AFTER socket is unhashed to avoid closed
1807 * socket sitting in hash tables.
1808 */
1809 sk->sk_state = state;
1810
1811 #ifdef STATE_TRACE
1812 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1813 #endif
1814 }
1815 EXPORT_SYMBOL_GPL(tcp_set_state);
1816
1817 /*
1818 * State processing on a close. This implements the state shift for
1819 * sending our FIN frame. Note that we only send a FIN for some
1820 * states. A shutdown() may have already sent the FIN, or we may be
1821 * closed.
1822 */
1823
1824 static const unsigned char new_state[16] = {
1825 /* current state: new state: action: */
1826 /* (Invalid) */ TCP_CLOSE,
1827 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1828 /* TCP_SYN_SENT */ TCP_CLOSE,
1829 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1830 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1831 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1832 /* TCP_TIME_WAIT */ TCP_CLOSE,
1833 /* TCP_CLOSE */ TCP_CLOSE,
1834 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1835 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1836 /* TCP_LISTEN */ TCP_CLOSE,
1837 /* TCP_CLOSING */ TCP_CLOSING,
1838 };
1839
1840 static int tcp_close_state(struct sock *sk)
1841 {
1842 int next = (int)new_state[sk->sk_state];
1843 int ns = next & TCP_STATE_MASK;
1844
1845 tcp_set_state(sk, ns);
1846
1847 return next & TCP_ACTION_FIN;
1848 }
1849
1850 /*
1851 * Shutdown the sending side of a connection. Much like close except
1852 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1853 */
1854
1855 void tcp_shutdown(struct sock *sk, int how)
1856 {
1857 /* We need to grab some memory, and put together a FIN,
1858 * and then put it into the queue to be sent.
1859 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1860 */
1861 if (!(how & SEND_SHUTDOWN))
1862 return;
1863
1864 /* If we've already sent a FIN, or it's a closed state, skip this. */
1865 if ((1 << sk->sk_state) &
1866 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1867 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1868 /* Clear out any half completed packets. FIN if needed. */
1869 if (tcp_close_state(sk))
1870 tcp_send_fin(sk);
1871 }
1872 }
1873
1874 void tcp_close(struct sock *sk, long timeout)
1875 {
1876 struct sk_buff *skb;
1877 int data_was_unread = 0;
1878 int state;
1879
1880 lock_sock(sk);
1881 sk->sk_shutdown = SHUTDOWN_MASK;
1882
1883 if (sk->sk_state == TCP_LISTEN) {
1884 tcp_set_state(sk, TCP_CLOSE);
1885
1886 /* Special case. */
1887 inet_csk_listen_stop(sk);
1888
1889 goto adjudge_to_death;
1890 }
1891
1892 /* We need to flush the recv. buffs. We do this only on the
1893 * descriptor close, not protocol-sourced closes, because the
1894 * reader process may not have drained the data yet!
1895 */
1896 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1897 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1898 tcp_hdr(skb)->fin;
1899 data_was_unread += len;
1900 __kfree_skb(skb);
1901 }
1902
1903 sk_mem_reclaim(sk);
1904
1905 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1906 * data was lost. To witness the awful effects of the old behavior of
1907 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1908 * GET in an FTP client, suspend the process, wait for the client to
1909 * advertise a zero window, then kill -9 the FTP client, wheee...
1910 * Note: timeout is always zero in such a case.
1911 */
1912 if (data_was_unread) {
1913 /* Unread data was tossed, zap the connection. */
1914 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1915 tcp_set_state(sk, TCP_CLOSE);
1916 tcp_send_active_reset(sk, sk->sk_allocation);
1917 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1918 /* Check zero linger _after_ checking for unread data. */
1919 sk->sk_prot->disconnect(sk, 0);
1920 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1921 } else if (tcp_close_state(sk)) {
1922 /* We FIN if the application ate all the data before
1923 * zapping the connection.
1924 */
1925
1926 /* RED-PEN. Formally speaking, we have broken TCP state
1927 * machine. State transitions:
1928 *
1929 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1930 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1931 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1932 *
1933 * are legal only when FIN has been sent (i.e. in window),
1934 * rather than queued out of window. Purists blame.
1935 *
1936 * F.e. "RFC state" is ESTABLISHED,
1937 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1938 *
1939 * The visible declinations are that sometimes
1940 * we enter time-wait state, when it is not required really
1941 * (harmless), do not send active resets, when they are
1942 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1943 * they look as CLOSING or LAST_ACK for Linux)
1944 * Probably, I missed some more holelets.
1945 * --ANK
1946 */
1947 tcp_send_fin(sk);
1948 }
1949
1950 sk_stream_wait_close(sk, timeout);
1951
1952 adjudge_to_death:
1953 state = sk->sk_state;
1954 sock_hold(sk);
1955 sock_orphan(sk);
1956
1957 /* It is the last release_sock in its life. It will remove backlog. */
1958 release_sock(sk);
1959
1960
1961 /* Now socket is owned by kernel and we acquire BH lock
1962 to finish close. No need to check for user refs.
1963 */
1964 local_bh_disable();
1965 bh_lock_sock(sk);
1966 WARN_ON(sock_owned_by_user(sk));
1967
1968 percpu_counter_inc(sk->sk_prot->orphan_count);
1969
1970 /* Have we already been destroyed by a softirq or backlog? */
1971 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1972 goto out;
1973
1974 /* This is a (useful) BSD violating of the RFC. There is a
1975 * problem with TCP as specified in that the other end could
1976 * keep a socket open forever with no application left this end.
1977 * We use a 3 minute timeout (about the same as BSD) then kill
1978 * our end. If they send after that then tough - BUT: long enough
1979 * that we won't make the old 4*rto = almost no time - whoops
1980 * reset mistake.
1981 *
1982 * Nope, it was not mistake. It is really desired behaviour
1983 * f.e. on http servers, when such sockets are useless, but
1984 * consume significant resources. Let's do it with special
1985 * linger2 option. --ANK
1986 */
1987
1988 if (sk->sk_state == TCP_FIN_WAIT2) {
1989 struct tcp_sock *tp = tcp_sk(sk);
1990 if (tp->linger2 < 0) {
1991 tcp_set_state(sk, TCP_CLOSE);
1992 tcp_send_active_reset(sk, GFP_ATOMIC);
1993 NET_INC_STATS_BH(sock_net(sk),
1994 LINUX_MIB_TCPABORTONLINGER);
1995 } else {
1996 const int tmo = tcp_fin_time(sk);
1997
1998 if (tmo > TCP_TIMEWAIT_LEN) {
1999 inet_csk_reset_keepalive_timer(sk,
2000 tmo - TCP_TIMEWAIT_LEN);
2001 } else {
2002 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2003 goto out;
2004 }
2005 }
2006 }
2007 if (sk->sk_state != TCP_CLOSE) {
2008 sk_mem_reclaim(sk);
2009 if (tcp_too_many_orphans(sk, 0)) {
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 kref_init(&cvp->kref);
2181 }
2182 lock_sock(sk);
2183 tp->rx_opt.cookie_in_always =
2184 (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2185 tp->rx_opt.cookie_out_never = 0; /* false */
2186
2187 if (tp->cookie_values != NULL) {
2188 if (cvp != NULL) {
2189 /* Changed values are recorded by a changed
2190 * pointer, ensuring the cookie will differ,
2191 * without separately hashing each value later.
2192 */
2193 kref_put(&tp->cookie_values->kref,
2194 tcp_cookie_values_release);
2195 } else {
2196 cvp = tp->cookie_values;
2197 }
2198 }
2199
2200 if (cvp != NULL) {
2201 cvp->cookie_desired = ctd.tcpct_cookie_desired;
2202
2203 if (ctd.tcpct_used > 0) {
2204 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2205 ctd.tcpct_used);
2206 cvp->s_data_desired = ctd.tcpct_used;
2207 cvp->s_data_constant = 1; /* true */
2208 } else {
2209 /* No constant payload data. */
2210 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2211 cvp->s_data_constant = 0; /* false */
2212 }
2213
2214 tp->cookie_values = cvp;
2215 }
2216 release_sock(sk);
2217 return err;
2218 }
2219 default:
2220 /* fallthru */
2221 break;
2222 };
2223
2224 if (optlen < sizeof(int))
2225 return -EINVAL;
2226
2227 if (get_user(val, (int __user *)optval))
2228 return -EFAULT;
2229
2230 lock_sock(sk);
2231
2232 switch (optname) {
2233 case TCP_MAXSEG:
2234 /* Values greater than interface MTU won't take effect. However
2235 * at the point when this call is done we typically don't yet
2236 * know which interface is going to be used */
2237 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2238 err = -EINVAL;
2239 break;
2240 }
2241 tp->rx_opt.user_mss = val;
2242 break;
2243
2244 case TCP_NODELAY:
2245 if (val) {
2246 /* TCP_NODELAY is weaker than TCP_CORK, so that
2247 * this option on corked socket is remembered, but
2248 * it is not activated until cork is cleared.
2249 *
2250 * However, when TCP_NODELAY is set we make
2251 * an explicit push, which overrides even TCP_CORK
2252 * for currently queued segments.
2253 */
2254 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2255 tcp_push_pending_frames(sk);
2256 } else {
2257 tp->nonagle &= ~TCP_NAGLE_OFF;
2258 }
2259 break;
2260
2261 case TCP_THIN_LINEAR_TIMEOUTS:
2262 if (val < 0 || val > 1)
2263 err = -EINVAL;
2264 else
2265 tp->thin_lto = val;
2266 break;
2267
2268 case TCP_THIN_DUPACK:
2269 if (val < 0 || val > 1)
2270 err = -EINVAL;
2271 else
2272 tp->thin_dupack = val;
2273 break;
2274
2275 case TCP_CORK:
2276 /* When set indicates to always queue non-full frames.
2277 * Later the user clears this option and we transmit
2278 * any pending partial frames in the queue. This is
2279 * meant to be used alongside sendfile() to get properly
2280 * filled frames when the user (for example) must write
2281 * out headers with a write() call first and then use
2282 * sendfile to send out the data parts.
2283 *
2284 * TCP_CORK can be set together with TCP_NODELAY and it is
2285 * stronger than TCP_NODELAY.
2286 */
2287 if (val) {
2288 tp->nonagle |= TCP_NAGLE_CORK;
2289 } else {
2290 tp->nonagle &= ~TCP_NAGLE_CORK;
2291 if (tp->nonagle&TCP_NAGLE_OFF)
2292 tp->nonagle |= TCP_NAGLE_PUSH;
2293 tcp_push_pending_frames(sk);
2294 }
2295 break;
2296
2297 case TCP_KEEPIDLE:
2298 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2299 err = -EINVAL;
2300 else {
2301 tp->keepalive_time = val * HZ;
2302 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2303 !((1 << sk->sk_state) &
2304 (TCPF_CLOSE | TCPF_LISTEN))) {
2305 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2306 if (tp->keepalive_time > elapsed)
2307 elapsed = tp->keepalive_time - elapsed;
2308 else
2309 elapsed = 0;
2310 inet_csk_reset_keepalive_timer(sk, elapsed);
2311 }
2312 }
2313 break;
2314 case TCP_KEEPINTVL:
2315 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2316 err = -EINVAL;
2317 else
2318 tp->keepalive_intvl = val * HZ;
2319 break;
2320 case TCP_KEEPCNT:
2321 if (val < 1 || val > MAX_TCP_KEEPCNT)
2322 err = -EINVAL;
2323 else
2324 tp->keepalive_probes = val;
2325 break;
2326 case TCP_SYNCNT:
2327 if (val < 1 || val > MAX_TCP_SYNCNT)
2328 err = -EINVAL;
2329 else
2330 icsk->icsk_syn_retries = val;
2331 break;
2332
2333 case TCP_LINGER2:
2334 if (val < 0)
2335 tp->linger2 = -1;
2336 else if (val > sysctl_tcp_fin_timeout / HZ)
2337 tp->linger2 = 0;
2338 else
2339 tp->linger2 = val * HZ;
2340 break;
2341
2342 case TCP_DEFER_ACCEPT:
2343 /* Translate value in seconds to number of retransmits */
2344 icsk->icsk_accept_queue.rskq_defer_accept =
2345 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2346 TCP_RTO_MAX / HZ);
2347 break;
2348
2349 case TCP_WINDOW_CLAMP:
2350 if (!val) {
2351 if (sk->sk_state != TCP_CLOSE) {
2352 err = -EINVAL;
2353 break;
2354 }
2355 tp->window_clamp = 0;
2356 } else
2357 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2358 SOCK_MIN_RCVBUF / 2 : val;
2359 break;
2360
2361 case TCP_QUICKACK:
2362 if (!val) {
2363 icsk->icsk_ack.pingpong = 1;
2364 } else {
2365 icsk->icsk_ack.pingpong = 0;
2366 if ((1 << sk->sk_state) &
2367 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2368 inet_csk_ack_scheduled(sk)) {
2369 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2370 tcp_cleanup_rbuf(sk, 1);
2371 if (!(val & 1))
2372 icsk->icsk_ack.pingpong = 1;
2373 }
2374 }
2375 break;
2376
2377 #ifdef CONFIG_TCP_MD5SIG
2378 case TCP_MD5SIG:
2379 /* Read the IP->Key mappings from userspace */
2380 err = tp->af_specific->md5_parse(sk, optval, optlen);
2381 break;
2382 #endif
2383
2384 default:
2385 err = -ENOPROTOOPT;
2386 break;
2387 }
2388
2389 release_sock(sk);
2390 return err;
2391 }
2392
2393 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2394 unsigned int optlen)
2395 {
2396 struct inet_connection_sock *icsk = inet_csk(sk);
2397
2398 if (level != SOL_TCP)
2399 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2400 optval, optlen);
2401 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2402 }
2403
2404 #ifdef CONFIG_COMPAT
2405 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2406 char __user *optval, unsigned int optlen)
2407 {
2408 if (level != SOL_TCP)
2409 return inet_csk_compat_setsockopt(sk, level, optname,
2410 optval, optlen);
2411 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2412 }
2413
2414 EXPORT_SYMBOL(compat_tcp_setsockopt);
2415 #endif
2416
2417 /* Return information about state of tcp endpoint in API format. */
2418 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2419 {
2420 struct tcp_sock *tp = tcp_sk(sk);
2421 const struct inet_connection_sock *icsk = inet_csk(sk);
2422 u32 now = tcp_time_stamp;
2423
2424 memset(info, 0, sizeof(*info));
2425
2426 info->tcpi_state = sk->sk_state;
2427 info->tcpi_ca_state = icsk->icsk_ca_state;
2428 info->tcpi_retransmits = icsk->icsk_retransmits;
2429 info->tcpi_probes = icsk->icsk_probes_out;
2430 info->tcpi_backoff = icsk->icsk_backoff;
2431
2432 if (tp->rx_opt.tstamp_ok)
2433 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2434 if (tcp_is_sack(tp))
2435 info->tcpi_options |= TCPI_OPT_SACK;
2436 if (tp->rx_opt.wscale_ok) {
2437 info->tcpi_options |= TCPI_OPT_WSCALE;
2438 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2439 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2440 }
2441
2442 if (tp->ecn_flags&TCP_ECN_OK)
2443 info->tcpi_options |= TCPI_OPT_ECN;
2444
2445 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2446 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2447 info->tcpi_snd_mss = tp->mss_cache;
2448 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2449
2450 if (sk->sk_state == TCP_LISTEN) {
2451 info->tcpi_unacked = sk->sk_ack_backlog;
2452 info->tcpi_sacked = sk->sk_max_ack_backlog;
2453 } else {
2454 info->tcpi_unacked = tp->packets_out;
2455 info->tcpi_sacked = tp->sacked_out;
2456 }
2457 info->tcpi_lost = tp->lost_out;
2458 info->tcpi_retrans = tp->retrans_out;
2459 info->tcpi_fackets = tp->fackets_out;
2460
2461 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2462 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2463 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2464
2465 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2466 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2467 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2468 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2469 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2470 info->tcpi_snd_cwnd = tp->snd_cwnd;
2471 info->tcpi_advmss = tp->advmss;
2472 info->tcpi_reordering = tp->reordering;
2473
2474 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2475 info->tcpi_rcv_space = tp->rcvq_space.space;
2476
2477 info->tcpi_total_retrans = tp->total_retrans;
2478 }
2479
2480 EXPORT_SYMBOL_GPL(tcp_get_info);
2481
2482 static int do_tcp_getsockopt(struct sock *sk, int level,
2483 int optname, char __user *optval, int __user *optlen)
2484 {
2485 struct inet_connection_sock *icsk = inet_csk(sk);
2486 struct tcp_sock *tp = tcp_sk(sk);
2487 int val, len;
2488
2489 if (get_user(len, optlen))
2490 return -EFAULT;
2491
2492 len = min_t(unsigned int, len, sizeof(int));
2493
2494 if (len < 0)
2495 return -EINVAL;
2496
2497 switch (optname) {
2498 case TCP_MAXSEG:
2499 val = tp->mss_cache;
2500 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2501 val = tp->rx_opt.user_mss;
2502 break;
2503 case TCP_NODELAY:
2504 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2505 break;
2506 case TCP_CORK:
2507 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2508 break;
2509 case TCP_KEEPIDLE:
2510 val = keepalive_time_when(tp) / HZ;
2511 break;
2512 case TCP_KEEPINTVL:
2513 val = keepalive_intvl_when(tp) / HZ;
2514 break;
2515 case TCP_KEEPCNT:
2516 val = keepalive_probes(tp);
2517 break;
2518 case TCP_SYNCNT:
2519 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2520 break;
2521 case TCP_LINGER2:
2522 val = tp->linger2;
2523 if (val >= 0)
2524 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2525 break;
2526 case TCP_DEFER_ACCEPT:
2527 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2528 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2529 break;
2530 case TCP_WINDOW_CLAMP:
2531 val = tp->window_clamp;
2532 break;
2533 case TCP_INFO: {
2534 struct tcp_info info;
2535
2536 if (get_user(len, optlen))
2537 return -EFAULT;
2538
2539 tcp_get_info(sk, &info);
2540
2541 len = min_t(unsigned int, len, sizeof(info));
2542 if (put_user(len, optlen))
2543 return -EFAULT;
2544 if (copy_to_user(optval, &info, len))
2545 return -EFAULT;
2546 return 0;
2547 }
2548 case TCP_QUICKACK:
2549 val = !icsk->icsk_ack.pingpong;
2550 break;
2551
2552 case TCP_CONGESTION:
2553 if (get_user(len, optlen))
2554 return -EFAULT;
2555 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2556 if (put_user(len, optlen))
2557 return -EFAULT;
2558 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2559 return -EFAULT;
2560 return 0;
2561
2562 case TCP_COOKIE_TRANSACTIONS: {
2563 struct tcp_cookie_transactions ctd;
2564 struct tcp_cookie_values *cvp = tp->cookie_values;
2565
2566 if (get_user(len, optlen))
2567 return -EFAULT;
2568 if (len < sizeof(ctd))
2569 return -EINVAL;
2570
2571 memset(&ctd, 0, sizeof(ctd));
2572 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2573 TCP_COOKIE_IN_ALWAYS : 0)
2574 | (tp->rx_opt.cookie_out_never ?
2575 TCP_COOKIE_OUT_NEVER : 0);
2576
2577 if (cvp != NULL) {
2578 ctd.tcpct_flags |= (cvp->s_data_in ?
2579 TCP_S_DATA_IN : 0)
2580 | (cvp->s_data_out ?
2581 TCP_S_DATA_OUT : 0);
2582
2583 ctd.tcpct_cookie_desired = cvp->cookie_desired;
2584 ctd.tcpct_s_data_desired = cvp->s_data_desired;
2585
2586 memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2587 cvp->cookie_pair_size);
2588 ctd.tcpct_used = cvp->cookie_pair_size;
2589 }
2590
2591 if (put_user(sizeof(ctd), optlen))
2592 return -EFAULT;
2593 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2594 return -EFAULT;
2595 return 0;
2596 }
2597 default:
2598 return -ENOPROTOOPT;
2599 }
2600
2601 if (put_user(len, optlen))
2602 return -EFAULT;
2603 if (copy_to_user(optval, &val, len))
2604 return -EFAULT;
2605 return 0;
2606 }
2607
2608 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2609 int __user *optlen)
2610 {
2611 struct inet_connection_sock *icsk = inet_csk(sk);
2612
2613 if (level != SOL_TCP)
2614 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2615 optval, optlen);
2616 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2617 }
2618
2619 #ifdef CONFIG_COMPAT
2620 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2621 char __user *optval, int __user *optlen)
2622 {
2623 if (level != SOL_TCP)
2624 return inet_csk_compat_getsockopt(sk, level, optname,
2625 optval, optlen);
2626 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2627 }
2628
2629 EXPORT_SYMBOL(compat_tcp_getsockopt);
2630 #endif
2631
2632 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2633 {
2634 struct sk_buff *segs = ERR_PTR(-EINVAL);
2635 struct tcphdr *th;
2636 unsigned thlen;
2637 unsigned int seq;
2638 __be32 delta;
2639 unsigned int oldlen;
2640 unsigned int mss;
2641
2642 if (!pskb_may_pull(skb, sizeof(*th)))
2643 goto out;
2644
2645 th = tcp_hdr(skb);
2646 thlen = th->doff * 4;
2647 if (thlen < sizeof(*th))
2648 goto out;
2649
2650 if (!pskb_may_pull(skb, thlen))
2651 goto out;
2652
2653 oldlen = (u16)~skb->len;
2654 __skb_pull(skb, thlen);
2655
2656 mss = skb_shinfo(skb)->gso_size;
2657 if (unlikely(skb->len <= mss))
2658 goto out;
2659
2660 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2661 /* Packet is from an untrusted source, reset gso_segs. */
2662 int type = skb_shinfo(skb)->gso_type;
2663
2664 if (unlikely(type &
2665 ~(SKB_GSO_TCPV4 |
2666 SKB_GSO_DODGY |
2667 SKB_GSO_TCP_ECN |
2668 SKB_GSO_TCPV6 |
2669 0) ||
2670 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2671 goto out;
2672
2673 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2674
2675 segs = NULL;
2676 goto out;
2677 }
2678
2679 segs = skb_segment(skb, features);
2680 if (IS_ERR(segs))
2681 goto out;
2682
2683 delta = htonl(oldlen + (thlen + mss));
2684
2685 skb = segs;
2686 th = tcp_hdr(skb);
2687 seq = ntohl(th->seq);
2688
2689 do {
2690 th->fin = th->psh = 0;
2691
2692 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2693 (__force u32)delta));
2694 if (skb->ip_summed != CHECKSUM_PARTIAL)
2695 th->check =
2696 csum_fold(csum_partial(skb_transport_header(skb),
2697 thlen, skb->csum));
2698
2699 seq += mss;
2700 skb = skb->next;
2701 th = tcp_hdr(skb);
2702
2703 th->seq = htonl(seq);
2704 th->cwr = 0;
2705 } while (skb->next);
2706
2707 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2708 skb->data_len);
2709 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2710 (__force u32)delta));
2711 if (skb->ip_summed != CHECKSUM_PARTIAL)
2712 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2713 thlen, skb->csum));
2714
2715 out:
2716 return segs;
2717 }
2718 EXPORT_SYMBOL(tcp_tso_segment);
2719
2720 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2721 {
2722 struct sk_buff **pp = NULL;
2723 struct sk_buff *p;
2724 struct tcphdr *th;
2725 struct tcphdr *th2;
2726 unsigned int len;
2727 unsigned int thlen;
2728 unsigned int flags;
2729 unsigned int mss = 1;
2730 unsigned int hlen;
2731 unsigned int off;
2732 int flush = 1;
2733 int i;
2734
2735 off = skb_gro_offset(skb);
2736 hlen = off + sizeof(*th);
2737 th = skb_gro_header_fast(skb, off);
2738 if (skb_gro_header_hard(skb, hlen)) {
2739 th = skb_gro_header_slow(skb, hlen, off);
2740 if (unlikely(!th))
2741 goto out;
2742 }
2743
2744 thlen = th->doff * 4;
2745 if (thlen < sizeof(*th))
2746 goto out;
2747
2748 hlen = off + thlen;
2749 if (skb_gro_header_hard(skb, hlen)) {
2750 th = skb_gro_header_slow(skb, hlen, off);
2751 if (unlikely(!th))
2752 goto out;
2753 }
2754
2755 skb_gro_pull(skb, thlen);
2756
2757 len = skb_gro_len(skb);
2758 flags = tcp_flag_word(th);
2759
2760 for (; (p = *head); head = &p->next) {
2761 if (!NAPI_GRO_CB(p)->same_flow)
2762 continue;
2763
2764 th2 = tcp_hdr(p);
2765
2766 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2767 NAPI_GRO_CB(p)->same_flow = 0;
2768 continue;
2769 }
2770
2771 goto found;
2772 }
2773
2774 goto out_check_final;
2775
2776 found:
2777 flush = NAPI_GRO_CB(p)->flush;
2778 flush |= flags & TCP_FLAG_CWR;
2779 flush |= (flags ^ tcp_flag_word(th2)) &
2780 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH);
2781 flush |= th->ack_seq ^ th2->ack_seq;
2782 for (i = sizeof(*th); i < thlen; i += 4)
2783 flush |= *(u32 *)((u8 *)th + i) ^
2784 *(u32 *)((u8 *)th2 + i);
2785
2786 mss = skb_shinfo(p)->gso_size;
2787
2788 flush |= (len - 1) >= mss;
2789 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2790
2791 if (flush || skb_gro_receive(head, skb)) {
2792 mss = 1;
2793 goto out_check_final;
2794 }
2795
2796 p = *head;
2797 th2 = tcp_hdr(p);
2798 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2799
2800 out_check_final:
2801 flush = len < mss;
2802 flush |= flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST |
2803 TCP_FLAG_SYN | TCP_FLAG_FIN);
2804
2805 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2806 pp = head;
2807
2808 out:
2809 NAPI_GRO_CB(skb)->flush |= flush;
2810
2811 return pp;
2812 }
2813 EXPORT_SYMBOL(tcp_gro_receive);
2814
2815 int tcp_gro_complete(struct sk_buff *skb)
2816 {
2817 struct tcphdr *th = tcp_hdr(skb);
2818
2819 skb->csum_start = skb_transport_header(skb) - skb->head;
2820 skb->csum_offset = offsetof(struct tcphdr, check);
2821 skb->ip_summed = CHECKSUM_PARTIAL;
2822
2823 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2824
2825 if (th->cwr)
2826 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2827
2828 return 0;
2829 }
2830 EXPORT_SYMBOL(tcp_gro_complete);
2831
2832 #ifdef CONFIG_TCP_MD5SIG
2833 static unsigned long tcp_md5sig_users;
2834 static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool;
2835 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2836
2837 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool)
2838 {
2839 int cpu;
2840 for_each_possible_cpu(cpu) {
2841 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2842 if (p) {
2843 if (p->md5_desc.tfm)
2844 crypto_free_hash(p->md5_desc.tfm);
2845 kfree(p);
2846 }
2847 }
2848 free_percpu(pool);
2849 }
2850
2851 void tcp_free_md5sig_pool(void)
2852 {
2853 struct tcp_md5sig_pool * __percpu *pool = NULL;
2854
2855 spin_lock_bh(&tcp_md5sig_pool_lock);
2856 if (--tcp_md5sig_users == 0) {
2857 pool = tcp_md5sig_pool;
2858 tcp_md5sig_pool = NULL;
2859 }
2860 spin_unlock_bh(&tcp_md5sig_pool_lock);
2861 if (pool)
2862 __tcp_free_md5sig_pool(pool);
2863 }
2864
2865 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2866
2867 static struct tcp_md5sig_pool * __percpu *
2868 __tcp_alloc_md5sig_pool(struct sock *sk)
2869 {
2870 int cpu;
2871 struct tcp_md5sig_pool * __percpu *pool;
2872
2873 pool = alloc_percpu(struct tcp_md5sig_pool *);
2874 if (!pool)
2875 return NULL;
2876
2877 for_each_possible_cpu(cpu) {
2878 struct tcp_md5sig_pool *p;
2879 struct crypto_hash *hash;
2880
2881 p = kzalloc(sizeof(*p), sk->sk_allocation);
2882 if (!p)
2883 goto out_free;
2884 *per_cpu_ptr(pool, cpu) = p;
2885
2886 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2887 if (!hash || IS_ERR(hash))
2888 goto out_free;
2889
2890 p->md5_desc.tfm = hash;
2891 }
2892 return pool;
2893 out_free:
2894 __tcp_free_md5sig_pool(pool);
2895 return NULL;
2896 }
2897
2898 struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
2899 {
2900 struct tcp_md5sig_pool * __percpu *pool;
2901 int alloc = 0;
2902
2903 retry:
2904 spin_lock_bh(&tcp_md5sig_pool_lock);
2905 pool = tcp_md5sig_pool;
2906 if (tcp_md5sig_users++ == 0) {
2907 alloc = 1;
2908 spin_unlock_bh(&tcp_md5sig_pool_lock);
2909 } else if (!pool) {
2910 tcp_md5sig_users--;
2911 spin_unlock_bh(&tcp_md5sig_pool_lock);
2912 cpu_relax();
2913 goto retry;
2914 } else
2915 spin_unlock_bh(&tcp_md5sig_pool_lock);
2916
2917 if (alloc) {
2918 /* we cannot hold spinlock here because this may sleep. */
2919 struct tcp_md5sig_pool * __percpu *p;
2920
2921 p = __tcp_alloc_md5sig_pool(sk);
2922 spin_lock_bh(&tcp_md5sig_pool_lock);
2923 if (!p) {
2924 tcp_md5sig_users--;
2925 spin_unlock_bh(&tcp_md5sig_pool_lock);
2926 return NULL;
2927 }
2928 pool = tcp_md5sig_pool;
2929 if (pool) {
2930 /* oops, it has already been assigned. */
2931 spin_unlock_bh(&tcp_md5sig_pool_lock);
2932 __tcp_free_md5sig_pool(p);
2933 } else {
2934 tcp_md5sig_pool = pool = p;
2935 spin_unlock_bh(&tcp_md5sig_pool_lock);
2936 }
2937 }
2938 return pool;
2939 }
2940
2941 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2942
2943
2944 /**
2945 * tcp_get_md5sig_pool - get md5sig_pool for this user
2946 *
2947 * We use percpu structure, so if we succeed, we exit with preemption
2948 * and BH disabled, to make sure another thread or softirq handling
2949 * wont try to get same context.
2950 */
2951 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2952 {
2953 struct tcp_md5sig_pool * __percpu *p;
2954
2955 local_bh_disable();
2956
2957 spin_lock(&tcp_md5sig_pool_lock);
2958 p = tcp_md5sig_pool;
2959 if (p)
2960 tcp_md5sig_users++;
2961 spin_unlock(&tcp_md5sig_pool_lock);
2962
2963 if (p)
2964 return *per_cpu_ptr(p, smp_processor_id());
2965
2966 local_bh_enable();
2967 return NULL;
2968 }
2969 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2970
2971 void tcp_put_md5sig_pool(void)
2972 {
2973 local_bh_enable();
2974 tcp_free_md5sig_pool();
2975 }
2976 EXPORT_SYMBOL(tcp_put_md5sig_pool);
2977
2978 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2979 struct tcphdr *th)
2980 {
2981 struct scatterlist sg;
2982 int err;
2983
2984 __sum16 old_checksum = th->check;
2985 th->check = 0;
2986 /* options aren't included in the hash */
2987 sg_init_one(&sg, th, sizeof(struct tcphdr));
2988 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
2989 th->check = old_checksum;
2990 return err;
2991 }
2992
2993 EXPORT_SYMBOL(tcp_md5_hash_header);
2994
2995 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2996 struct sk_buff *skb, unsigned header_len)
2997 {
2998 struct scatterlist sg;
2999 const struct tcphdr *tp = tcp_hdr(skb);
3000 struct hash_desc *desc = &hp->md5_desc;
3001 unsigned i;
3002 const unsigned head_data_len = skb_headlen(skb) > header_len ?
3003 skb_headlen(skb) - header_len : 0;
3004 const struct skb_shared_info *shi = skb_shinfo(skb);
3005
3006 sg_init_table(&sg, 1);
3007
3008 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3009 if (crypto_hash_update(desc, &sg, head_data_len))
3010 return 1;
3011
3012 for (i = 0; i < shi->nr_frags; ++i) {
3013 const struct skb_frag_struct *f = &shi->frags[i];
3014 sg_set_page(&sg, f->page, f->size, f->page_offset);
3015 if (crypto_hash_update(desc, &sg, f->size))
3016 return 1;
3017 }
3018
3019 return 0;
3020 }
3021
3022 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3023
3024 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
3025 {
3026 struct scatterlist sg;
3027
3028 sg_init_one(&sg, key->key, key->keylen);
3029 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3030 }
3031
3032 EXPORT_SYMBOL(tcp_md5_hash_key);
3033
3034 #endif
3035
3036 /**
3037 * Each Responder maintains up to two secret values concurrently for
3038 * efficient secret rollover. Each secret value has 4 states:
3039 *
3040 * Generating. (tcp_secret_generating != tcp_secret_primary)
3041 * Generates new Responder-Cookies, but not yet used for primary
3042 * verification. This is a short-term state, typically lasting only
3043 * one round trip time (RTT).
3044 *
3045 * Primary. (tcp_secret_generating == tcp_secret_primary)
3046 * Used both for generation and primary verification.
3047 *
3048 * Retiring. (tcp_secret_retiring != tcp_secret_secondary)
3049 * Used for verification, until the first failure that can be
3050 * verified by the newer Generating secret. At that time, this
3051 * cookie's state is changed to Secondary, and the Generating
3052 * cookie's state is changed to Primary. This is a short-term state,
3053 * typically lasting only one round trip time (RTT).
3054 *
3055 * Secondary. (tcp_secret_retiring == tcp_secret_secondary)
3056 * Used for secondary verification, after primary verification
3057 * failures. This state lasts no more than twice the Maximum Segment
3058 * Lifetime (2MSL). Then, the secret is discarded.
3059 */
3060 struct tcp_cookie_secret {
3061 /* The secret is divided into two parts. The digest part is the
3062 * equivalent of previously hashing a secret and saving the state,
3063 * and serves as an initialization vector (IV). The message part
3064 * serves as the trailing secret.
3065 */
3066 u32 secrets[COOKIE_WORKSPACE_WORDS];
3067 unsigned long expires;
3068 };
3069
3070 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3071 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3072 #define TCP_SECRET_LIFE (HZ * 600)
3073
3074 static struct tcp_cookie_secret tcp_secret_one;
3075 static struct tcp_cookie_secret tcp_secret_two;
3076
3077 /* Essentially a circular list, without dynamic allocation. */
3078 static struct tcp_cookie_secret *tcp_secret_generating;
3079 static struct tcp_cookie_secret *tcp_secret_primary;
3080 static struct tcp_cookie_secret *tcp_secret_retiring;
3081 static struct tcp_cookie_secret *tcp_secret_secondary;
3082
3083 static DEFINE_SPINLOCK(tcp_secret_locker);
3084
3085 /* Select a pseudo-random word in the cookie workspace.
3086 */
3087 static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3088 {
3089 return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3090 }
3091
3092 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3093 * Called in softirq context.
3094 * Returns: 0 for success.
3095 */
3096 int tcp_cookie_generator(u32 *bakery)
3097 {
3098 unsigned long jiffy = jiffies;
3099
3100 if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3101 spin_lock_bh(&tcp_secret_locker);
3102 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3103 /* refreshed by another */
3104 memcpy(bakery,
3105 &tcp_secret_generating->secrets[0],
3106 COOKIE_WORKSPACE_WORDS);
3107 } else {
3108 /* still needs refreshing */
3109 get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3110
3111 /* The first time, paranoia assumes that the
3112 * randomization function isn't as strong. But,
3113 * this secret initialization is delayed until
3114 * the last possible moment (packet arrival).
3115 * Although that time is observable, it is
3116 * unpredictably variable. Mash in the most
3117 * volatile clock bits available, and expire the
3118 * secret extra quickly.
3119 */
3120 if (unlikely(tcp_secret_primary->expires ==
3121 tcp_secret_secondary->expires)) {
3122 struct timespec tv;
3123
3124 getnstimeofday(&tv);
3125 bakery[COOKIE_DIGEST_WORDS+0] ^=
3126 (u32)tv.tv_nsec;
3127
3128 tcp_secret_secondary->expires = jiffy
3129 + TCP_SECRET_1MSL
3130 + (0x0f & tcp_cookie_work(bakery, 0));
3131 } else {
3132 tcp_secret_secondary->expires = jiffy
3133 + TCP_SECRET_LIFE
3134 + (0xff & tcp_cookie_work(bakery, 1));
3135 tcp_secret_primary->expires = jiffy
3136 + TCP_SECRET_2MSL
3137 + (0x1f & tcp_cookie_work(bakery, 2));
3138 }
3139 memcpy(&tcp_secret_secondary->secrets[0],
3140 bakery, COOKIE_WORKSPACE_WORDS);
3141
3142 rcu_assign_pointer(tcp_secret_generating,
3143 tcp_secret_secondary);
3144 rcu_assign_pointer(tcp_secret_retiring,
3145 tcp_secret_primary);
3146 /*
3147 * Neither call_rcu() nor synchronize_rcu() needed.
3148 * Retiring data is not freed. It is replaced after
3149 * further (locked) pointer updates, and a quiet time
3150 * (minimum 1MSL, maximum LIFE - 2MSL).
3151 */
3152 }
3153 spin_unlock_bh(&tcp_secret_locker);
3154 } else {
3155 rcu_read_lock_bh();
3156 memcpy(bakery,
3157 &rcu_dereference(tcp_secret_generating)->secrets[0],
3158 COOKIE_WORKSPACE_WORDS);
3159 rcu_read_unlock_bh();
3160 }
3161 return 0;
3162 }
3163 EXPORT_SYMBOL(tcp_cookie_generator);
3164
3165 void tcp_done(struct sock *sk)
3166 {
3167 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3168 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3169
3170 tcp_set_state(sk, TCP_CLOSE);
3171 tcp_clear_xmit_timers(sk);
3172
3173 sk->sk_shutdown = SHUTDOWN_MASK;
3174
3175 if (!sock_flag(sk, SOCK_DEAD))
3176 sk->sk_state_change(sk);
3177 else
3178 inet_csk_destroy_sock(sk);
3179 }
3180 EXPORT_SYMBOL_GPL(tcp_done);
3181
3182 extern struct tcp_congestion_ops tcp_reno;
3183
3184 static __initdata unsigned long thash_entries;
3185 static int __init set_thash_entries(char *str)
3186 {
3187 if (!str)
3188 return 0;
3189 thash_entries = simple_strtoul(str, &str, 0);
3190 return 1;
3191 }
3192 __setup("thash_entries=", set_thash_entries);
3193
3194 void __init tcp_init(void)
3195 {
3196 struct sk_buff *skb = NULL;
3197 unsigned long nr_pages, limit;
3198 int i, max_share, cnt;
3199 unsigned long jiffy = jiffies;
3200
3201 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3202
3203 percpu_counter_init(&tcp_sockets_allocated, 0);
3204 percpu_counter_init(&tcp_orphan_count, 0);
3205 tcp_hashinfo.bind_bucket_cachep =
3206 kmem_cache_create("tcp_bind_bucket",
3207 sizeof(struct inet_bind_bucket), 0,
3208 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3209
3210 /* Size and allocate the main established and bind bucket
3211 * hash tables.
3212 *
3213 * The methodology is similar to that of the buffer cache.
3214 */
3215 tcp_hashinfo.ehash =
3216 alloc_large_system_hash("TCP established",
3217 sizeof(struct inet_ehash_bucket),
3218 thash_entries,
3219 (totalram_pages >= 128 * 1024) ?
3220 13 : 15,
3221 0,
3222 NULL,
3223 &tcp_hashinfo.ehash_mask,
3224 thash_entries ? 0 : 512 * 1024);
3225 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3226 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3227 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3228 }
3229 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3230 panic("TCP: failed to alloc ehash_locks");
3231 tcp_hashinfo.bhash =
3232 alloc_large_system_hash("TCP bind",
3233 sizeof(struct inet_bind_hashbucket),
3234 tcp_hashinfo.ehash_mask + 1,
3235 (totalram_pages >= 128 * 1024) ?
3236 13 : 15,
3237 0,
3238 &tcp_hashinfo.bhash_size,
3239 NULL,
3240 64 * 1024);
3241 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
3242 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3243 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3244 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3245 }
3246
3247
3248 cnt = tcp_hashinfo.ehash_mask + 1;
3249
3250 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3251 sysctl_tcp_max_orphans = cnt / 2;
3252 sysctl_max_syn_backlog = max(128, cnt / 256);
3253
3254 /* Set the pressure threshold to be a fraction of global memory that
3255 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
3256 * memory, with a floor of 128 pages.
3257 */
3258 nr_pages = totalram_pages - totalhigh_pages;
3259 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
3260 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
3261 limit = max(limit, 128UL);
3262 sysctl_tcp_mem[0] = limit / 4 * 3;
3263 sysctl_tcp_mem[1] = limit;
3264 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3265
3266 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3267 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
3268 max_share = min(4UL*1024*1024, limit);
3269
3270 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3271 sysctl_tcp_wmem[1] = 16*1024;
3272 sysctl_tcp_wmem[2] = max(64*1024, max_share);
3273
3274 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3275 sysctl_tcp_rmem[1] = 87380;
3276 sysctl_tcp_rmem[2] = max(87380, max_share);
3277
3278 printk(KERN_INFO "TCP: Hash tables configured "
3279 "(established %u bind %u)\n",
3280 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3281
3282 tcp_register_congestion_control(&tcp_reno);
3283
3284 memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3285 memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3286 tcp_secret_one.expires = jiffy; /* past due */
3287 tcp_secret_two.expires = jiffy; /* past due */
3288 tcp_secret_generating = &tcp_secret_one;
3289 tcp_secret_primary = &tcp_secret_one;
3290 tcp_secret_retiring = &tcp_secret_two;
3291 tcp_secret_secondary = &tcp_secret_two;
3292 }
3293
3294 EXPORT_SYMBOL(tcp_close);
3295 EXPORT_SYMBOL(tcp_disconnect);
3296 EXPORT_SYMBOL(tcp_getsockopt);
3297 EXPORT_SYMBOL(tcp_ioctl);
3298 EXPORT_SYMBOL(tcp_poll);
3299 EXPORT_SYMBOL(tcp_read_sock);
3300 EXPORT_SYMBOL(tcp_recvmsg);
3301 EXPORT_SYMBOL(tcp_sendmsg);
3302 EXPORT_SYMBOL(tcp_splice_read);
3303 EXPORT_SYMBOL(tcp_sendpage);
3304 EXPORT_SYMBOL(tcp_setsockopt);
3305 EXPORT_SYMBOL(tcp_shutdown);
Linux ARM platform port for MOXA ART SoC