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tcp: Repair socket queues
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / ipv4 / tcp.c
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * 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 #define pr_fmt(fmt) "TCP: " fmt
249
250 #include <linux/kernel.h>
251 #include <linux/module.h>
252 #include <linux/types.h>
253 #include <linux/fcntl.h>
254 #include <linux/poll.h>
255 #include <linux/init.h>
256 #include <linux/fs.h>
257 #include <linux/skbuff.h>
258 #include <linux/scatterlist.h>
259 #include <linux/splice.h>
260 #include <linux/net.h>
261 #include <linux/socket.h>
262 #include <linux/random.h>
263 #include <linux/bootmem.h>
264 #include <linux/highmem.h>
265 #include <linux/swap.h>
266 #include <linux/cache.h>
267 #include <linux/err.h>
268 #include <linux/crypto.h>
269 #include <linux/time.h>
270 #include <linux/slab.h>
271
272 #include <net/icmp.h>
273 #include <net/tcp.h>
274 #include <net/xfrm.h>
275 #include <net/ip.h>
276 #include <net/netdma.h>
277 #include <net/sock.h>
278
279 #include <asm/uaccess.h>
280 #include <asm/ioctls.h>
281
282 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
283
284 struct percpu_counter tcp_orphan_count;
285 EXPORT_SYMBOL_GPL(tcp_orphan_count);
286
287 int sysctl_tcp_wmem[3] __read_mostly;
288 int sysctl_tcp_rmem[3] __read_mostly;
289
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 EXPORT_SYMBOL(tcp_memory_pressure);
319
320 void tcp_enter_memory_pressure(struct sock *sk)
321 {
322 if (!tcp_memory_pressure) {
323 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
324 tcp_memory_pressure = 1;
325 }
326 }
327 EXPORT_SYMBOL(tcp_enter_memory_pressure);
328
329 /* Convert seconds to retransmits based on initial and max timeout */
330 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
331 {
332 u8 res = 0;
333
334 if (seconds > 0) {
335 int period = timeout;
336
337 res = 1;
338 while (seconds > period && res < 255) {
339 res++;
340 timeout <<= 1;
341 if (timeout > rto_max)
342 timeout = rto_max;
343 period += timeout;
344 }
345 }
346 return res;
347 }
348
349 /* Convert retransmits to seconds based on initial and max timeout */
350 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
351 {
352 int period = 0;
353
354 if (retrans > 0) {
355 period = timeout;
356 while (--retrans) {
357 timeout <<= 1;
358 if (timeout > rto_max)
359 timeout = rto_max;
360 period += timeout;
361 }
362 }
363 return period;
364 }
365
366 /*
367 * Wait for a TCP event.
368 *
369 * Note that we don't need to lock the socket, as the upper poll layers
370 * take care of normal races (between the test and the event) and we don't
371 * go look at any of the socket buffers directly.
372 */
373 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
374 {
375 unsigned int mask;
376 struct sock *sk = sock->sk;
377 const struct tcp_sock *tp = tcp_sk(sk);
378
379 sock_poll_wait(file, sk_sleep(sk), wait);
380 if (sk->sk_state == TCP_LISTEN)
381 return inet_csk_listen_poll(sk);
382
383 /* Socket is not locked. We are protected from async events
384 * by poll logic and correct handling of state changes
385 * made by other threads is impossible in any case.
386 */
387
388 mask = 0;
389
390 /*
391 * POLLHUP is certainly not done right. But poll() doesn't
392 * have a notion of HUP in just one direction, and for a
393 * socket the read side is more interesting.
394 *
395 * Some poll() documentation says that POLLHUP is incompatible
396 * with the POLLOUT/POLLWR flags, so somebody should check this
397 * all. But careful, it tends to be safer to return too many
398 * bits than too few, and you can easily break real applications
399 * if you don't tell them that something has hung up!
400 *
401 * Check-me.
402 *
403 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
404 * our fs/select.c). It means that after we received EOF,
405 * poll always returns immediately, making impossible poll() on write()
406 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
407 * if and only if shutdown has been made in both directions.
408 * Actually, it is interesting to look how Solaris and DUX
409 * solve this dilemma. I would prefer, if POLLHUP were maskable,
410 * then we could set it on SND_SHUTDOWN. BTW examples given
411 * in Stevens' books assume exactly this behaviour, it explains
412 * why POLLHUP is incompatible with POLLOUT. --ANK
413 *
414 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
415 * blocking on fresh not-connected or disconnected socket. --ANK
416 */
417 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
418 mask |= POLLHUP;
419 if (sk->sk_shutdown & RCV_SHUTDOWN)
420 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
421
422 /* Connected? */
423 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
424 int target = sock_rcvlowat(sk, 0, INT_MAX);
425
426 if (tp->urg_seq == tp->copied_seq &&
427 !sock_flag(sk, SOCK_URGINLINE) &&
428 tp->urg_data)
429 target++;
430
431 /* Potential race condition. If read of tp below will
432 * escape above sk->sk_state, we can be illegally awaken
433 * in SYN_* states. */
434 if (tp->rcv_nxt - tp->copied_seq >= target)
435 mask |= POLLIN | POLLRDNORM;
436
437 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
438 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
439 mask |= POLLOUT | POLLWRNORM;
440 } else { /* send SIGIO later */
441 set_bit(SOCK_ASYNC_NOSPACE,
442 &sk->sk_socket->flags);
443 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
444
445 /* Race breaker. If space is freed after
446 * wspace test but before the flags are set,
447 * IO signal will be lost.
448 */
449 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
450 mask |= POLLOUT | POLLWRNORM;
451 }
452 } else
453 mask |= POLLOUT | POLLWRNORM;
454
455 if (tp->urg_data & TCP_URG_VALID)
456 mask |= POLLPRI;
457 }
458 /* This barrier is coupled with smp_wmb() in tcp_reset() */
459 smp_rmb();
460 if (sk->sk_err)
461 mask |= POLLERR;
462
463 return mask;
464 }
465 EXPORT_SYMBOL(tcp_poll);
466
467 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
468 {
469 struct tcp_sock *tp = tcp_sk(sk);
470 int answ;
471
472 switch (cmd) {
473 case SIOCINQ:
474 if (sk->sk_state == TCP_LISTEN)
475 return -EINVAL;
476
477 lock_sock(sk);
478 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
479 answ = 0;
480 else if (sock_flag(sk, SOCK_URGINLINE) ||
481 !tp->urg_data ||
482 before(tp->urg_seq, tp->copied_seq) ||
483 !before(tp->urg_seq, tp->rcv_nxt)) {
484 struct sk_buff *skb;
485
486 answ = tp->rcv_nxt - tp->copied_seq;
487
488 /* Subtract 1, if FIN is in queue. */
489 skb = skb_peek_tail(&sk->sk_receive_queue);
490 if (answ && skb)
491 answ -= tcp_hdr(skb)->fin;
492 } else
493 answ = tp->urg_seq - tp->copied_seq;
494 release_sock(sk);
495 break;
496 case SIOCATMARK:
497 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
498 break;
499 case SIOCOUTQ:
500 if (sk->sk_state == TCP_LISTEN)
501 return -EINVAL;
502
503 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
504 answ = 0;
505 else
506 answ = tp->write_seq - tp->snd_una;
507 break;
508 case SIOCOUTQNSD:
509 if (sk->sk_state == TCP_LISTEN)
510 return -EINVAL;
511
512 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
513 answ = 0;
514 else
515 answ = tp->write_seq - tp->snd_nxt;
516 break;
517 default:
518 return -ENOIOCTLCMD;
519 }
520
521 return put_user(answ, (int __user *)arg);
522 }
523 EXPORT_SYMBOL(tcp_ioctl);
524
525 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
526 {
527 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
528 tp->pushed_seq = tp->write_seq;
529 }
530
531 static inline int forced_push(const struct tcp_sock *tp)
532 {
533 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
534 }
535
536 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
537 {
538 struct tcp_sock *tp = tcp_sk(sk);
539 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
540
541 skb->csum = 0;
542 tcb->seq = tcb->end_seq = tp->write_seq;
543 tcb->tcp_flags = TCPHDR_ACK;
544 tcb->sacked = 0;
545 skb_header_release(skb);
546 tcp_add_write_queue_tail(sk, skb);
547 sk->sk_wmem_queued += skb->truesize;
548 sk_mem_charge(sk, skb->truesize);
549 if (tp->nonagle & TCP_NAGLE_PUSH)
550 tp->nonagle &= ~TCP_NAGLE_PUSH;
551 }
552
553 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
554 {
555 if (flags & MSG_OOB)
556 tp->snd_up = tp->write_seq;
557 }
558
559 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
560 int nonagle)
561 {
562 if (tcp_send_head(sk)) {
563 struct tcp_sock *tp = tcp_sk(sk);
564
565 if (!(flags & MSG_MORE) || forced_push(tp))
566 tcp_mark_push(tp, tcp_write_queue_tail(sk));
567
568 tcp_mark_urg(tp, flags);
569 __tcp_push_pending_frames(sk, mss_now,
570 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
571 }
572 }
573
574 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
575 unsigned int offset, size_t len)
576 {
577 struct tcp_splice_state *tss = rd_desc->arg.data;
578 int ret;
579
580 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
581 tss->flags);
582 if (ret > 0)
583 rd_desc->count -= ret;
584 return ret;
585 }
586
587 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
588 {
589 /* Store TCP splice context information in read_descriptor_t. */
590 read_descriptor_t rd_desc = {
591 .arg.data = tss,
592 .count = tss->len,
593 };
594
595 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
596 }
597
598 /**
599 * tcp_splice_read - splice data from TCP socket to a pipe
600 * @sock: socket to splice from
601 * @ppos: position (not valid)
602 * @pipe: pipe to splice to
603 * @len: number of bytes to splice
604 * @flags: splice modifier flags
605 *
606 * Description:
607 * Will read pages from given socket and fill them into a pipe.
608 *
609 **/
610 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
611 struct pipe_inode_info *pipe, size_t len,
612 unsigned int flags)
613 {
614 struct sock *sk = sock->sk;
615 struct tcp_splice_state tss = {
616 .pipe = pipe,
617 .len = len,
618 .flags = flags,
619 };
620 long timeo;
621 ssize_t spliced;
622 int ret;
623
624 sock_rps_record_flow(sk);
625 /*
626 * We can't seek on a socket input
627 */
628 if (unlikely(*ppos))
629 return -ESPIPE;
630
631 ret = spliced = 0;
632
633 lock_sock(sk);
634
635 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
636 while (tss.len) {
637 ret = __tcp_splice_read(sk, &tss);
638 if (ret < 0)
639 break;
640 else if (!ret) {
641 if (spliced)
642 break;
643 if (sock_flag(sk, SOCK_DONE))
644 break;
645 if (sk->sk_err) {
646 ret = sock_error(sk);
647 break;
648 }
649 if (sk->sk_shutdown & RCV_SHUTDOWN)
650 break;
651 if (sk->sk_state == TCP_CLOSE) {
652 /*
653 * This occurs when user tries to read
654 * from never connected socket.
655 */
656 if (!sock_flag(sk, SOCK_DONE))
657 ret = -ENOTCONN;
658 break;
659 }
660 if (!timeo) {
661 ret = -EAGAIN;
662 break;
663 }
664 sk_wait_data(sk, &timeo);
665 if (signal_pending(current)) {
666 ret = sock_intr_errno(timeo);
667 break;
668 }
669 continue;
670 }
671 tss.len -= ret;
672 spliced += ret;
673
674 if (!timeo)
675 break;
676 release_sock(sk);
677 lock_sock(sk);
678
679 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
680 (sk->sk_shutdown & RCV_SHUTDOWN) ||
681 signal_pending(current))
682 break;
683 }
684
685 release_sock(sk);
686
687 if (spliced)
688 return spliced;
689
690 return ret;
691 }
692 EXPORT_SYMBOL(tcp_splice_read);
693
694 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
695 {
696 struct sk_buff *skb;
697
698 /* The TCP header must be at least 32-bit aligned. */
699 size = ALIGN(size, 4);
700
701 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
702 if (skb) {
703 if (sk_wmem_schedule(sk, skb->truesize)) {
704 skb_reserve(skb, sk->sk_prot->max_header);
705 /*
706 * Make sure that we have exactly size bytes
707 * available to the caller, no more, no less.
708 */
709 skb->avail_size = size;
710 return skb;
711 }
712 __kfree_skb(skb);
713 } else {
714 sk->sk_prot->enter_memory_pressure(sk);
715 sk_stream_moderate_sndbuf(sk);
716 }
717 return NULL;
718 }
719
720 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
721 int large_allowed)
722 {
723 struct tcp_sock *tp = tcp_sk(sk);
724 u32 xmit_size_goal, old_size_goal;
725
726 xmit_size_goal = mss_now;
727
728 if (large_allowed && sk_can_gso(sk)) {
729 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
730 inet_csk(sk)->icsk_af_ops->net_header_len -
731 inet_csk(sk)->icsk_ext_hdr_len -
732 tp->tcp_header_len);
733
734 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
735
736 /* We try hard to avoid divides here */
737 old_size_goal = tp->xmit_size_goal_segs * mss_now;
738
739 if (likely(old_size_goal <= xmit_size_goal &&
740 old_size_goal + mss_now > xmit_size_goal)) {
741 xmit_size_goal = old_size_goal;
742 } else {
743 tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
744 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
745 }
746 }
747
748 return max(xmit_size_goal, mss_now);
749 }
750
751 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
752 {
753 int mss_now;
754
755 mss_now = tcp_current_mss(sk);
756 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
757
758 return mss_now;
759 }
760
761 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
762 size_t psize, int flags)
763 {
764 struct tcp_sock *tp = tcp_sk(sk);
765 int mss_now, size_goal;
766 int err;
767 ssize_t copied;
768 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
769
770 /* Wait for a connection to finish. */
771 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
772 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
773 goto out_err;
774
775 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
776
777 mss_now = tcp_send_mss(sk, &size_goal, flags);
778 copied = 0;
779
780 err = -EPIPE;
781 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
782 goto out_err;
783
784 while (psize > 0) {
785 struct sk_buff *skb = tcp_write_queue_tail(sk);
786 struct page *page = pages[poffset / PAGE_SIZE];
787 int copy, i, can_coalesce;
788 int offset = poffset % PAGE_SIZE;
789 int size = min_t(size_t, psize, PAGE_SIZE - offset);
790
791 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
792 new_segment:
793 if (!sk_stream_memory_free(sk))
794 goto wait_for_sndbuf;
795
796 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
797 if (!skb)
798 goto wait_for_memory;
799
800 skb_entail(sk, skb);
801 copy = size_goal;
802 }
803
804 if (copy > size)
805 copy = size;
806
807 i = skb_shinfo(skb)->nr_frags;
808 can_coalesce = skb_can_coalesce(skb, i, page, offset);
809 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
810 tcp_mark_push(tp, skb);
811 goto new_segment;
812 }
813 if (!sk_wmem_schedule(sk, copy))
814 goto wait_for_memory;
815
816 if (can_coalesce) {
817 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
818 } else {
819 get_page(page);
820 skb_fill_page_desc(skb, i, page, offset, copy);
821 }
822
823 skb->len += copy;
824 skb->data_len += copy;
825 skb->truesize += copy;
826 sk->sk_wmem_queued += copy;
827 sk_mem_charge(sk, copy);
828 skb->ip_summed = CHECKSUM_PARTIAL;
829 tp->write_seq += copy;
830 TCP_SKB_CB(skb)->end_seq += copy;
831 skb_shinfo(skb)->gso_segs = 0;
832
833 if (!copied)
834 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
835
836 copied += copy;
837 poffset += copy;
838 if (!(psize -= copy))
839 goto out;
840
841 if (skb->len < size_goal || (flags & MSG_OOB))
842 continue;
843
844 if (forced_push(tp)) {
845 tcp_mark_push(tp, skb);
846 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
847 } else if (skb == tcp_send_head(sk))
848 tcp_push_one(sk, mss_now);
849 continue;
850
851 wait_for_sndbuf:
852 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
853 wait_for_memory:
854 if (copied)
855 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
856
857 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
858 goto do_error;
859
860 mss_now = tcp_send_mss(sk, &size_goal, flags);
861 }
862
863 out:
864 if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
865 tcp_push(sk, flags, mss_now, tp->nonagle);
866 return copied;
867
868 do_error:
869 if (copied)
870 goto out;
871 out_err:
872 return sk_stream_error(sk, flags, err);
873 }
874
875 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
876 size_t size, int flags)
877 {
878 ssize_t res;
879
880 if (!(sk->sk_route_caps & NETIF_F_SG) ||
881 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
882 return sock_no_sendpage(sk->sk_socket, page, offset, size,
883 flags);
884
885 lock_sock(sk);
886 res = do_tcp_sendpages(sk, &page, offset, size, flags);
887 release_sock(sk);
888 return res;
889 }
890 EXPORT_SYMBOL(tcp_sendpage);
891
892 static inline int select_size(const struct sock *sk, bool sg)
893 {
894 const struct tcp_sock *tp = tcp_sk(sk);
895 int tmp = tp->mss_cache;
896
897 if (sg) {
898 if (sk_can_gso(sk)) {
899 /* Small frames wont use a full page:
900 * Payload will immediately follow tcp header.
901 */
902 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
903 } else {
904 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
905
906 if (tmp >= pgbreak &&
907 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
908 tmp = pgbreak;
909 }
910 }
911
912 return tmp;
913 }
914
915 static int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size)
916 {
917 struct sk_buff *skb;
918 struct tcp_skb_cb *cb;
919 struct tcphdr *th;
920
921 skb = alloc_skb(size + sizeof(*th), sk->sk_allocation);
922 if (!skb)
923 goto err;
924
925 th = (struct tcphdr *)skb_put(skb, sizeof(*th));
926 skb_reset_transport_header(skb);
927 memset(th, 0, sizeof(*th));
928
929 if (memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size))
930 goto err_free;
931
932 cb = TCP_SKB_CB(skb);
933
934 TCP_SKB_CB(skb)->seq = tcp_sk(sk)->rcv_nxt;
935 TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + size;
936 TCP_SKB_CB(skb)->ack_seq = tcp_sk(sk)->snd_una - 1;
937
938 tcp_queue_rcv(sk, skb, sizeof(*th));
939
940 return size;
941
942 err_free:
943 kfree_skb(skb);
944 err:
945 return -ENOMEM;
946 }
947
948 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
949 size_t size)
950 {
951 struct iovec *iov;
952 struct tcp_sock *tp = tcp_sk(sk);
953 struct sk_buff *skb;
954 int iovlen, flags, err, copied;
955 int mss_now = 0, size_goal;
956 bool sg;
957 long timeo;
958
959 lock_sock(sk);
960
961 flags = msg->msg_flags;
962 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
963
964 /* Wait for a connection to finish. */
965 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
966 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
967 goto out_err;
968
969 if (unlikely(tp->repair)) {
970 if (tp->repair_queue == TCP_RECV_QUEUE) {
971 copied = tcp_send_rcvq(sk, msg, size);
972 goto out;
973 }
974
975 err = -EINVAL;
976 if (tp->repair_queue == TCP_NO_QUEUE)
977 goto out_err;
978
979 /* 'common' sending to sendq */
980 }
981
982 /* This should be in poll */
983 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
984
985 mss_now = tcp_send_mss(sk, &size_goal, flags);
986
987 /* Ok commence sending. */
988 iovlen = msg->msg_iovlen;
989 iov = msg->msg_iov;
990 copied = 0;
991
992 err = -EPIPE;
993 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
994 goto out_err;
995
996 sg = !!(sk->sk_route_caps & NETIF_F_SG);
997
998 while (--iovlen >= 0) {
999 size_t seglen = iov->iov_len;
1000 unsigned char __user *from = iov->iov_base;
1001
1002 iov++;
1003
1004 while (seglen > 0) {
1005 int copy = 0;
1006 int max = size_goal;
1007
1008 skb = tcp_write_queue_tail(sk);
1009 if (tcp_send_head(sk)) {
1010 if (skb->ip_summed == CHECKSUM_NONE)
1011 max = mss_now;
1012 copy = max - skb->len;
1013 }
1014
1015 if (copy <= 0) {
1016 new_segment:
1017 /* Allocate new segment. If the interface is SG,
1018 * allocate skb fitting to single page.
1019 */
1020 if (!sk_stream_memory_free(sk))
1021 goto wait_for_sndbuf;
1022
1023 skb = sk_stream_alloc_skb(sk,
1024 select_size(sk, sg),
1025 sk->sk_allocation);
1026 if (!skb)
1027 goto wait_for_memory;
1028
1029 /*
1030 * Check whether we can use HW checksum.
1031 */
1032 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1033 skb->ip_summed = CHECKSUM_PARTIAL;
1034
1035 skb_entail(sk, skb);
1036 copy = size_goal;
1037 max = size_goal;
1038 }
1039
1040 /* Try to append data to the end of skb. */
1041 if (copy > seglen)
1042 copy = seglen;
1043
1044 /* Where to copy to? */
1045 if (skb_availroom(skb) > 0) {
1046 /* We have some space in skb head. Superb! */
1047 copy = min_t(int, copy, skb_availroom(skb));
1048 err = skb_add_data_nocache(sk, skb, from, copy);
1049 if (err)
1050 goto do_fault;
1051 } else {
1052 int merge = 0;
1053 int i = skb_shinfo(skb)->nr_frags;
1054 struct page *page = sk->sk_sndmsg_page;
1055 int off;
1056
1057 if (page && page_count(page) == 1)
1058 sk->sk_sndmsg_off = 0;
1059
1060 off = sk->sk_sndmsg_off;
1061
1062 if (skb_can_coalesce(skb, i, page, off) &&
1063 off != PAGE_SIZE) {
1064 /* We can extend the last page
1065 * fragment. */
1066 merge = 1;
1067 } else if (i == MAX_SKB_FRAGS || !sg) {
1068 /* Need to add new fragment and cannot
1069 * do this because interface is non-SG,
1070 * or because all the page slots are
1071 * busy. */
1072 tcp_mark_push(tp, skb);
1073 goto new_segment;
1074 } else if (page) {
1075 if (off == PAGE_SIZE) {
1076 put_page(page);
1077 sk->sk_sndmsg_page = page = NULL;
1078 off = 0;
1079 }
1080 } else
1081 off = 0;
1082
1083 if (copy > PAGE_SIZE - off)
1084 copy = PAGE_SIZE - off;
1085
1086 if (!sk_wmem_schedule(sk, copy))
1087 goto wait_for_memory;
1088
1089 if (!page) {
1090 /* Allocate new cache page. */
1091 if (!(page = sk_stream_alloc_page(sk)))
1092 goto wait_for_memory;
1093 }
1094
1095 /* Time to copy data. We are close to
1096 * the end! */
1097 err = skb_copy_to_page_nocache(sk, from, skb,
1098 page, off, copy);
1099 if (err) {
1100 /* If this page was new, give it to the
1101 * socket so it does not get leaked.
1102 */
1103 if (!sk->sk_sndmsg_page) {
1104 sk->sk_sndmsg_page = page;
1105 sk->sk_sndmsg_off = 0;
1106 }
1107 goto do_error;
1108 }
1109
1110 /* Update the skb. */
1111 if (merge) {
1112 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1113 } else {
1114 skb_fill_page_desc(skb, i, page, off, copy);
1115 if (sk->sk_sndmsg_page) {
1116 get_page(page);
1117 } else if (off + copy < PAGE_SIZE) {
1118 get_page(page);
1119 sk->sk_sndmsg_page = page;
1120 }
1121 }
1122
1123 sk->sk_sndmsg_off = off + copy;
1124 }
1125
1126 if (!copied)
1127 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1128
1129 tp->write_seq += copy;
1130 TCP_SKB_CB(skb)->end_seq += copy;
1131 skb_shinfo(skb)->gso_segs = 0;
1132
1133 from += copy;
1134 copied += copy;
1135 if ((seglen -= copy) == 0 && iovlen == 0)
1136 goto out;
1137
1138 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1139 continue;
1140
1141 if (forced_push(tp)) {
1142 tcp_mark_push(tp, skb);
1143 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1144 } else if (skb == tcp_send_head(sk))
1145 tcp_push_one(sk, mss_now);
1146 continue;
1147
1148 wait_for_sndbuf:
1149 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1150 wait_for_memory:
1151 if (copied && likely(!tp->repair))
1152 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1153
1154 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1155 goto do_error;
1156
1157 mss_now = tcp_send_mss(sk, &size_goal, flags);
1158 }
1159 }
1160
1161 out:
1162 if (copied && likely(!tp->repair))
1163 tcp_push(sk, flags, mss_now, tp->nonagle);
1164 release_sock(sk);
1165 return copied;
1166
1167 do_fault:
1168 if (!skb->len) {
1169 tcp_unlink_write_queue(skb, sk);
1170 /* It is the one place in all of TCP, except connection
1171 * reset, where we can be unlinking the send_head.
1172 */
1173 tcp_check_send_head(sk, skb);
1174 sk_wmem_free_skb(sk, skb);
1175 }
1176
1177 do_error:
1178 if (copied)
1179 goto out;
1180 out_err:
1181 err = sk_stream_error(sk, flags, err);
1182 release_sock(sk);
1183 return err;
1184 }
1185 EXPORT_SYMBOL(tcp_sendmsg);
1186
1187 /*
1188 * Handle reading urgent data. BSD has very simple semantics for
1189 * this, no blocking and very strange errors 8)
1190 */
1191
1192 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1193 {
1194 struct tcp_sock *tp = tcp_sk(sk);
1195
1196 /* No URG data to read. */
1197 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1198 tp->urg_data == TCP_URG_READ)
1199 return -EINVAL; /* Yes this is right ! */
1200
1201 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1202 return -ENOTCONN;
1203
1204 if (tp->urg_data & TCP_URG_VALID) {
1205 int err = 0;
1206 char c = tp->urg_data;
1207
1208 if (!(flags & MSG_PEEK))
1209 tp->urg_data = TCP_URG_READ;
1210
1211 /* Read urgent data. */
1212 msg->msg_flags |= MSG_OOB;
1213
1214 if (len > 0) {
1215 if (!(flags & MSG_TRUNC))
1216 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1217 len = 1;
1218 } else
1219 msg->msg_flags |= MSG_TRUNC;
1220
1221 return err ? -EFAULT : len;
1222 }
1223
1224 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1225 return 0;
1226
1227 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1228 * the available implementations agree in this case:
1229 * this call should never block, independent of the
1230 * blocking state of the socket.
1231 * Mike <pall@rz.uni-karlsruhe.de>
1232 */
1233 return -EAGAIN;
1234 }
1235
1236 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1237 {
1238 struct sk_buff *skb;
1239 int copied = 0, err = 0;
1240
1241 /* XXX -- need to support SO_PEEK_OFF */
1242
1243 skb_queue_walk(&sk->sk_write_queue, skb) {
1244 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len);
1245 if (err)
1246 break;
1247
1248 copied += skb->len;
1249 }
1250
1251 return err ?: copied;
1252 }
1253
1254 /* Clean up the receive buffer for full frames taken by the user,
1255 * then send an ACK if necessary. COPIED is the number of bytes
1256 * tcp_recvmsg has given to the user so far, it speeds up the
1257 * calculation of whether or not we must ACK for the sake of
1258 * a window update.
1259 */
1260 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1261 {
1262 struct tcp_sock *tp = tcp_sk(sk);
1263 int time_to_ack = 0;
1264
1265 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1266
1267 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1268 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1269 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1270
1271 if (inet_csk_ack_scheduled(sk)) {
1272 const struct inet_connection_sock *icsk = inet_csk(sk);
1273 /* Delayed ACKs frequently hit locked sockets during bulk
1274 * receive. */
1275 if (icsk->icsk_ack.blocked ||
1276 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1277 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1278 /*
1279 * If this read emptied read buffer, we send ACK, if
1280 * connection is not bidirectional, user drained
1281 * receive buffer and there was a small segment
1282 * in queue.
1283 */
1284 (copied > 0 &&
1285 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1286 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1287 !icsk->icsk_ack.pingpong)) &&
1288 !atomic_read(&sk->sk_rmem_alloc)))
1289 time_to_ack = 1;
1290 }
1291
1292 /* We send an ACK if we can now advertise a non-zero window
1293 * which has been raised "significantly".
1294 *
1295 * Even if window raised up to infinity, do not send window open ACK
1296 * in states, where we will not receive more. It is useless.
1297 */
1298 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1299 __u32 rcv_window_now = tcp_receive_window(tp);
1300
1301 /* Optimize, __tcp_select_window() is not cheap. */
1302 if (2*rcv_window_now <= tp->window_clamp) {
1303 __u32 new_window = __tcp_select_window(sk);
1304
1305 /* Send ACK now, if this read freed lots of space
1306 * in our buffer. Certainly, new_window is new window.
1307 * We can advertise it now, if it is not less than current one.
1308 * "Lots" means "at least twice" here.
1309 */
1310 if (new_window && new_window >= 2 * rcv_window_now)
1311 time_to_ack = 1;
1312 }
1313 }
1314 if (time_to_ack)
1315 tcp_send_ack(sk);
1316 }
1317
1318 static void tcp_prequeue_process(struct sock *sk)
1319 {
1320 struct sk_buff *skb;
1321 struct tcp_sock *tp = tcp_sk(sk);
1322
1323 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1324
1325 /* RX process wants to run with disabled BHs, though it is not
1326 * necessary */
1327 local_bh_disable();
1328 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1329 sk_backlog_rcv(sk, skb);
1330 local_bh_enable();
1331
1332 /* Clear memory counter. */
1333 tp->ucopy.memory = 0;
1334 }
1335
1336 #ifdef CONFIG_NET_DMA
1337 static void tcp_service_net_dma(struct sock *sk, bool wait)
1338 {
1339 dma_cookie_t done, used;
1340 dma_cookie_t last_issued;
1341 struct tcp_sock *tp = tcp_sk(sk);
1342
1343 if (!tp->ucopy.dma_chan)
1344 return;
1345
1346 last_issued = tp->ucopy.dma_cookie;
1347 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1348
1349 do {
1350 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1351 last_issued, &done,
1352 &used) == DMA_SUCCESS) {
1353 /* Safe to free early-copied skbs now */
1354 __skb_queue_purge(&sk->sk_async_wait_queue);
1355 break;
1356 } else {
1357 struct sk_buff *skb;
1358 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1359 (dma_async_is_complete(skb->dma_cookie, done,
1360 used) == DMA_SUCCESS)) {
1361 __skb_dequeue(&sk->sk_async_wait_queue);
1362 kfree_skb(skb);
1363 }
1364 }
1365 } while (wait);
1366 }
1367 #endif
1368
1369 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1370 {
1371 struct sk_buff *skb;
1372 u32 offset;
1373
1374 skb_queue_walk(&sk->sk_receive_queue, skb) {
1375 offset = seq - TCP_SKB_CB(skb)->seq;
1376 if (tcp_hdr(skb)->syn)
1377 offset--;
1378 if (offset < skb->len || tcp_hdr(skb)->fin) {
1379 *off = offset;
1380 return skb;
1381 }
1382 }
1383 return NULL;
1384 }
1385
1386 /*
1387 * This routine provides an alternative to tcp_recvmsg() for routines
1388 * that would like to handle copying from skbuffs directly in 'sendfile'
1389 * fashion.
1390 * Note:
1391 * - It is assumed that the socket was locked by the caller.
1392 * - The routine does not block.
1393 * - At present, there is no support for reading OOB data
1394 * or for 'peeking' the socket using this routine
1395 * (although both would be easy to implement).
1396 */
1397 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1398 sk_read_actor_t recv_actor)
1399 {
1400 struct sk_buff *skb;
1401 struct tcp_sock *tp = tcp_sk(sk);
1402 u32 seq = tp->copied_seq;
1403 u32 offset;
1404 int copied = 0;
1405
1406 if (sk->sk_state == TCP_LISTEN)
1407 return -ENOTCONN;
1408 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1409 if (offset < skb->len) {
1410 int used;
1411 size_t len;
1412
1413 len = skb->len - offset;
1414 /* Stop reading if we hit a patch of urgent data */
1415 if (tp->urg_data) {
1416 u32 urg_offset = tp->urg_seq - seq;
1417 if (urg_offset < len)
1418 len = urg_offset;
1419 if (!len)
1420 break;
1421 }
1422 used = recv_actor(desc, skb, offset, len);
1423 if (used < 0) {
1424 if (!copied)
1425 copied = used;
1426 break;
1427 } else if (used <= len) {
1428 seq += used;
1429 copied += used;
1430 offset += used;
1431 }
1432 /*
1433 * If recv_actor drops the lock (e.g. TCP splice
1434 * receive) the skb pointer might be invalid when
1435 * getting here: tcp_collapse might have deleted it
1436 * while aggregating skbs from the socket queue.
1437 */
1438 skb = tcp_recv_skb(sk, seq-1, &offset);
1439 if (!skb || (offset+1 != skb->len))
1440 break;
1441 }
1442 if (tcp_hdr(skb)->fin) {
1443 sk_eat_skb(sk, skb, 0);
1444 ++seq;
1445 break;
1446 }
1447 sk_eat_skb(sk, skb, 0);
1448 if (!desc->count)
1449 break;
1450 tp->copied_seq = seq;
1451 }
1452 tp->copied_seq = seq;
1453
1454 tcp_rcv_space_adjust(sk);
1455
1456 /* Clean up data we have read: This will do ACK frames. */
1457 if (copied > 0)
1458 tcp_cleanup_rbuf(sk, copied);
1459 return copied;
1460 }
1461 EXPORT_SYMBOL(tcp_read_sock);
1462
1463 /*
1464 * This routine copies from a sock struct into the user buffer.
1465 *
1466 * Technical note: in 2.3 we work on _locked_ socket, so that
1467 * tricks with *seq access order and skb->users are not required.
1468 * Probably, code can be easily improved even more.
1469 */
1470
1471 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1472 size_t len, int nonblock, int flags, int *addr_len)
1473 {
1474 struct tcp_sock *tp = tcp_sk(sk);
1475 int copied = 0;
1476 u32 peek_seq;
1477 u32 *seq;
1478 unsigned long used;
1479 int err;
1480 int target; /* Read at least this many bytes */
1481 long timeo;
1482 struct task_struct *user_recv = NULL;
1483 int copied_early = 0;
1484 struct sk_buff *skb;
1485 u32 urg_hole = 0;
1486
1487 lock_sock(sk);
1488
1489 err = -ENOTCONN;
1490 if (sk->sk_state == TCP_LISTEN)
1491 goto out;
1492
1493 timeo = sock_rcvtimeo(sk, nonblock);
1494
1495 /* Urgent data needs to be handled specially. */
1496 if (flags & MSG_OOB)
1497 goto recv_urg;
1498
1499 if (unlikely(tp->repair)) {
1500 err = -EPERM;
1501 if (!(flags & MSG_PEEK))
1502 goto out;
1503
1504 if (tp->repair_queue == TCP_SEND_QUEUE)
1505 goto recv_sndq;
1506
1507 err = -EINVAL;
1508 if (tp->repair_queue == TCP_NO_QUEUE)
1509 goto out;
1510
1511 /* 'common' recv queue MSG_PEEK-ing */
1512 }
1513
1514 seq = &tp->copied_seq;
1515 if (flags & MSG_PEEK) {
1516 peek_seq = tp->copied_seq;
1517 seq = &peek_seq;
1518 }
1519
1520 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1521
1522 #ifdef CONFIG_NET_DMA
1523 tp->ucopy.dma_chan = NULL;
1524 preempt_disable();
1525 skb = skb_peek_tail(&sk->sk_receive_queue);
1526 {
1527 int available = 0;
1528
1529 if (skb)
1530 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1531 if ((available < target) &&
1532 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1533 !sysctl_tcp_low_latency &&
1534 net_dma_find_channel()) {
1535 preempt_enable_no_resched();
1536 tp->ucopy.pinned_list =
1537 dma_pin_iovec_pages(msg->msg_iov, len);
1538 } else {
1539 preempt_enable_no_resched();
1540 }
1541 }
1542 #endif
1543
1544 do {
1545 u32 offset;
1546
1547 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1548 if (tp->urg_data && tp->urg_seq == *seq) {
1549 if (copied)
1550 break;
1551 if (signal_pending(current)) {
1552 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1553 break;
1554 }
1555 }
1556
1557 /* Next get a buffer. */
1558
1559 skb_queue_walk(&sk->sk_receive_queue, skb) {
1560 /* Now that we have two receive queues this
1561 * shouldn't happen.
1562 */
1563 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1564 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1565 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1566 flags))
1567 break;
1568
1569 offset = *seq - TCP_SKB_CB(skb)->seq;
1570 if (tcp_hdr(skb)->syn)
1571 offset--;
1572 if (offset < skb->len)
1573 goto found_ok_skb;
1574 if (tcp_hdr(skb)->fin)
1575 goto found_fin_ok;
1576 WARN(!(flags & MSG_PEEK),
1577 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1578 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1579 }
1580
1581 /* Well, if we have backlog, try to process it now yet. */
1582
1583 if (copied >= target && !sk->sk_backlog.tail)
1584 break;
1585
1586 if (copied) {
1587 if (sk->sk_err ||
1588 sk->sk_state == TCP_CLOSE ||
1589 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1590 !timeo ||
1591 signal_pending(current))
1592 break;
1593 } else {
1594 if (sock_flag(sk, SOCK_DONE))
1595 break;
1596
1597 if (sk->sk_err) {
1598 copied = sock_error(sk);
1599 break;
1600 }
1601
1602 if (sk->sk_shutdown & RCV_SHUTDOWN)
1603 break;
1604
1605 if (sk->sk_state == TCP_CLOSE) {
1606 if (!sock_flag(sk, SOCK_DONE)) {
1607 /* This occurs when user tries to read
1608 * from never connected socket.
1609 */
1610 copied = -ENOTCONN;
1611 break;
1612 }
1613 break;
1614 }
1615
1616 if (!timeo) {
1617 copied = -EAGAIN;
1618 break;
1619 }
1620
1621 if (signal_pending(current)) {
1622 copied = sock_intr_errno(timeo);
1623 break;
1624 }
1625 }
1626
1627 tcp_cleanup_rbuf(sk, copied);
1628
1629 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1630 /* Install new reader */
1631 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1632 user_recv = current;
1633 tp->ucopy.task = user_recv;
1634 tp->ucopy.iov = msg->msg_iov;
1635 }
1636
1637 tp->ucopy.len = len;
1638
1639 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1640 !(flags & (MSG_PEEK | MSG_TRUNC)));
1641
1642 /* Ugly... If prequeue is not empty, we have to
1643 * process it before releasing socket, otherwise
1644 * order will be broken at second iteration.
1645 * More elegant solution is required!!!
1646 *
1647 * Look: we have the following (pseudo)queues:
1648 *
1649 * 1. packets in flight
1650 * 2. backlog
1651 * 3. prequeue
1652 * 4. receive_queue
1653 *
1654 * Each queue can be processed only if the next ones
1655 * are empty. At this point we have empty receive_queue.
1656 * But prequeue _can_ be not empty after 2nd iteration,
1657 * when we jumped to start of loop because backlog
1658 * processing added something to receive_queue.
1659 * We cannot release_sock(), because backlog contains
1660 * packets arrived _after_ prequeued ones.
1661 *
1662 * Shortly, algorithm is clear --- to process all
1663 * the queues in order. We could make it more directly,
1664 * requeueing packets from backlog to prequeue, if
1665 * is not empty. It is more elegant, but eats cycles,
1666 * unfortunately.
1667 */
1668 if (!skb_queue_empty(&tp->ucopy.prequeue))
1669 goto do_prequeue;
1670
1671 /* __ Set realtime policy in scheduler __ */
1672 }
1673
1674 #ifdef CONFIG_NET_DMA
1675 if (tp->ucopy.dma_chan)
1676 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1677 #endif
1678 if (copied >= target) {
1679 /* Do not sleep, just process backlog. */
1680 release_sock(sk);
1681 lock_sock(sk);
1682 } else
1683 sk_wait_data(sk, &timeo);
1684
1685 #ifdef CONFIG_NET_DMA
1686 tcp_service_net_dma(sk, false); /* Don't block */
1687 tp->ucopy.wakeup = 0;
1688 #endif
1689
1690 if (user_recv) {
1691 int chunk;
1692
1693 /* __ Restore normal policy in scheduler __ */
1694
1695 if ((chunk = len - tp->ucopy.len) != 0) {
1696 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1697 len -= chunk;
1698 copied += chunk;
1699 }
1700
1701 if (tp->rcv_nxt == tp->copied_seq &&
1702 !skb_queue_empty(&tp->ucopy.prequeue)) {
1703 do_prequeue:
1704 tcp_prequeue_process(sk);
1705
1706 if ((chunk = len - tp->ucopy.len) != 0) {
1707 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1708 len -= chunk;
1709 copied += chunk;
1710 }
1711 }
1712 }
1713 if ((flags & MSG_PEEK) &&
1714 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1715 if (net_ratelimit())
1716 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1717 current->comm, task_pid_nr(current));
1718 peek_seq = tp->copied_seq;
1719 }
1720 continue;
1721
1722 found_ok_skb:
1723 /* Ok so how much can we use? */
1724 used = skb->len - offset;
1725 if (len < used)
1726 used = len;
1727
1728 /* Do we have urgent data here? */
1729 if (tp->urg_data) {
1730 u32 urg_offset = tp->urg_seq - *seq;
1731 if (urg_offset < used) {
1732 if (!urg_offset) {
1733 if (!sock_flag(sk, SOCK_URGINLINE)) {
1734 ++*seq;
1735 urg_hole++;
1736 offset++;
1737 used--;
1738 if (!used)
1739 goto skip_copy;
1740 }
1741 } else
1742 used = urg_offset;
1743 }
1744 }
1745
1746 if (!(flags & MSG_TRUNC)) {
1747 #ifdef CONFIG_NET_DMA
1748 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1749 tp->ucopy.dma_chan = net_dma_find_channel();
1750
1751 if (tp->ucopy.dma_chan) {
1752 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1753 tp->ucopy.dma_chan, skb, offset,
1754 msg->msg_iov, used,
1755 tp->ucopy.pinned_list);
1756
1757 if (tp->ucopy.dma_cookie < 0) {
1758
1759 pr_alert("%s: dma_cookie < 0\n",
1760 __func__);
1761
1762 /* Exception. Bailout! */
1763 if (!copied)
1764 copied = -EFAULT;
1765 break;
1766 }
1767
1768 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1769
1770 if ((offset + used) == skb->len)
1771 copied_early = 1;
1772
1773 } else
1774 #endif
1775 {
1776 err = skb_copy_datagram_iovec(skb, offset,
1777 msg->msg_iov, used);
1778 if (err) {
1779 /* Exception. Bailout! */
1780 if (!copied)
1781 copied = -EFAULT;
1782 break;
1783 }
1784 }
1785 }
1786
1787 *seq += used;
1788 copied += used;
1789 len -= used;
1790
1791 tcp_rcv_space_adjust(sk);
1792
1793 skip_copy:
1794 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1795 tp->urg_data = 0;
1796 tcp_fast_path_check(sk);
1797 }
1798 if (used + offset < skb->len)
1799 continue;
1800
1801 if (tcp_hdr(skb)->fin)
1802 goto found_fin_ok;
1803 if (!(flags & MSG_PEEK)) {
1804 sk_eat_skb(sk, skb, copied_early);
1805 copied_early = 0;
1806 }
1807 continue;
1808
1809 found_fin_ok:
1810 /* Process the FIN. */
1811 ++*seq;
1812 if (!(flags & MSG_PEEK)) {
1813 sk_eat_skb(sk, skb, copied_early);
1814 copied_early = 0;
1815 }
1816 break;
1817 } while (len > 0);
1818
1819 if (user_recv) {
1820 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1821 int chunk;
1822
1823 tp->ucopy.len = copied > 0 ? len : 0;
1824
1825 tcp_prequeue_process(sk);
1826
1827 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1828 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1829 len -= chunk;
1830 copied += chunk;
1831 }
1832 }
1833
1834 tp->ucopy.task = NULL;
1835 tp->ucopy.len = 0;
1836 }
1837
1838 #ifdef CONFIG_NET_DMA
1839 tcp_service_net_dma(sk, true); /* Wait for queue to drain */
1840 tp->ucopy.dma_chan = NULL;
1841
1842 if (tp->ucopy.pinned_list) {
1843 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1844 tp->ucopy.pinned_list = NULL;
1845 }
1846 #endif
1847
1848 /* According to UNIX98, msg_name/msg_namelen are ignored
1849 * on connected socket. I was just happy when found this 8) --ANK
1850 */
1851
1852 /* Clean up data we have read: This will do ACK frames. */
1853 tcp_cleanup_rbuf(sk, copied);
1854
1855 release_sock(sk);
1856 return copied;
1857
1858 out:
1859 release_sock(sk);
1860 return err;
1861
1862 recv_urg:
1863 err = tcp_recv_urg(sk, msg, len, flags);
1864 goto out;
1865
1866 recv_sndq:
1867 err = tcp_peek_sndq(sk, msg, len);
1868 goto out;
1869 }
1870 EXPORT_SYMBOL(tcp_recvmsg);
1871
1872 void tcp_set_state(struct sock *sk, int state)
1873 {
1874 int oldstate = sk->sk_state;
1875
1876 switch (state) {
1877 case TCP_ESTABLISHED:
1878 if (oldstate != TCP_ESTABLISHED)
1879 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1880 break;
1881
1882 case TCP_CLOSE:
1883 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1884 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1885
1886 sk->sk_prot->unhash(sk);
1887 if (inet_csk(sk)->icsk_bind_hash &&
1888 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1889 inet_put_port(sk);
1890 /* fall through */
1891 default:
1892 if (oldstate == TCP_ESTABLISHED)
1893 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1894 }
1895
1896 /* Change state AFTER socket is unhashed to avoid closed
1897 * socket sitting in hash tables.
1898 */
1899 sk->sk_state = state;
1900
1901 #ifdef STATE_TRACE
1902 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1903 #endif
1904 }
1905 EXPORT_SYMBOL_GPL(tcp_set_state);
1906
1907 /*
1908 * State processing on a close. This implements the state shift for
1909 * sending our FIN frame. Note that we only send a FIN for some
1910 * states. A shutdown() may have already sent the FIN, or we may be
1911 * closed.
1912 */
1913
1914 static const unsigned char new_state[16] = {
1915 /* current state: new state: action: */
1916 /* (Invalid) */ TCP_CLOSE,
1917 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1918 /* TCP_SYN_SENT */ TCP_CLOSE,
1919 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1920 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1921 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1922 /* TCP_TIME_WAIT */ TCP_CLOSE,
1923 /* TCP_CLOSE */ TCP_CLOSE,
1924 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1925 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1926 /* TCP_LISTEN */ TCP_CLOSE,
1927 /* TCP_CLOSING */ TCP_CLOSING,
1928 };
1929
1930 static int tcp_close_state(struct sock *sk)
1931 {
1932 int next = (int)new_state[sk->sk_state];
1933 int ns = next & TCP_STATE_MASK;
1934
1935 tcp_set_state(sk, ns);
1936
1937 return next & TCP_ACTION_FIN;
1938 }
1939
1940 /*
1941 * Shutdown the sending side of a connection. Much like close except
1942 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1943 */
1944
1945 void tcp_shutdown(struct sock *sk, int how)
1946 {
1947 /* We need to grab some memory, and put together a FIN,
1948 * and then put it into the queue to be sent.
1949 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1950 */
1951 if (!(how & SEND_SHUTDOWN))
1952 return;
1953
1954 /* If we've already sent a FIN, or it's a closed state, skip this. */
1955 if ((1 << sk->sk_state) &
1956 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1957 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1958 /* Clear out any half completed packets. FIN if needed. */
1959 if (tcp_close_state(sk))
1960 tcp_send_fin(sk);
1961 }
1962 }
1963 EXPORT_SYMBOL(tcp_shutdown);
1964
1965 bool tcp_check_oom(struct sock *sk, int shift)
1966 {
1967 bool too_many_orphans, out_of_socket_memory;
1968
1969 too_many_orphans = tcp_too_many_orphans(sk, shift);
1970 out_of_socket_memory = tcp_out_of_memory(sk);
1971
1972 if (too_many_orphans && net_ratelimit())
1973 pr_info("too many orphaned sockets\n");
1974 if (out_of_socket_memory && net_ratelimit())
1975 pr_info("out of memory -- consider tuning tcp_mem\n");
1976 return too_many_orphans || out_of_socket_memory;
1977 }
1978
1979 void tcp_close(struct sock *sk, long timeout)
1980 {
1981 struct sk_buff *skb;
1982 int data_was_unread = 0;
1983 int state;
1984
1985 lock_sock(sk);
1986 sk->sk_shutdown = SHUTDOWN_MASK;
1987
1988 if (sk->sk_state == TCP_LISTEN) {
1989 tcp_set_state(sk, TCP_CLOSE);
1990
1991 /* Special case. */
1992 inet_csk_listen_stop(sk);
1993
1994 goto adjudge_to_death;
1995 }
1996
1997 /* We need to flush the recv. buffs. We do this only on the
1998 * descriptor close, not protocol-sourced closes, because the
1999 * reader process may not have drained the data yet!
2000 */
2001 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2002 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
2003 tcp_hdr(skb)->fin;
2004 data_was_unread += len;
2005 __kfree_skb(skb);
2006 }
2007
2008 sk_mem_reclaim(sk);
2009
2010 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2011 if (sk->sk_state == TCP_CLOSE)
2012 goto adjudge_to_death;
2013
2014 /* As outlined in RFC 2525, section 2.17, we send a RST here because
2015 * data was lost. To witness the awful effects of the old behavior of
2016 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2017 * GET in an FTP client, suspend the process, wait for the client to
2018 * advertise a zero window, then kill -9 the FTP client, wheee...
2019 * Note: timeout is always zero in such a case.
2020 */
2021 if (unlikely(tcp_sk(sk)->repair)) {
2022 sk->sk_prot->disconnect(sk, 0);
2023 } else if (data_was_unread) {
2024 /* Unread data was tossed, zap the connection. */
2025 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2026 tcp_set_state(sk, TCP_CLOSE);
2027 tcp_send_active_reset(sk, sk->sk_allocation);
2028 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2029 /* Check zero linger _after_ checking for unread data. */
2030 sk->sk_prot->disconnect(sk, 0);
2031 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2032 } else if (tcp_close_state(sk)) {
2033 /* We FIN if the application ate all the data before
2034 * zapping the connection.
2035 */
2036
2037 /* RED-PEN. Formally speaking, we have broken TCP state
2038 * machine. State transitions:
2039 *
2040 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2041 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2042 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2043 *
2044 * are legal only when FIN has been sent (i.e. in window),
2045 * rather than queued out of window. Purists blame.
2046 *
2047 * F.e. "RFC state" is ESTABLISHED,
2048 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2049 *
2050 * The visible declinations are that sometimes
2051 * we enter time-wait state, when it is not required really
2052 * (harmless), do not send active resets, when they are
2053 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2054 * they look as CLOSING or LAST_ACK for Linux)
2055 * Probably, I missed some more holelets.
2056 * --ANK
2057 */
2058 tcp_send_fin(sk);
2059 }
2060
2061 sk_stream_wait_close(sk, timeout);
2062
2063 adjudge_to_death:
2064 state = sk->sk_state;
2065 sock_hold(sk);
2066 sock_orphan(sk);
2067
2068 /* It is the last release_sock in its life. It will remove backlog. */
2069 release_sock(sk);
2070
2071
2072 /* Now socket is owned by kernel and we acquire BH lock
2073 to finish close. No need to check for user refs.
2074 */
2075 local_bh_disable();
2076 bh_lock_sock(sk);
2077 WARN_ON(sock_owned_by_user(sk));
2078
2079 percpu_counter_inc(sk->sk_prot->orphan_count);
2080
2081 /* Have we already been destroyed by a softirq or backlog? */
2082 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2083 goto out;
2084
2085 /* This is a (useful) BSD violating of the RFC. There is a
2086 * problem with TCP as specified in that the other end could
2087 * keep a socket open forever with no application left this end.
2088 * We use a 3 minute timeout (about the same as BSD) then kill
2089 * our end. If they send after that then tough - BUT: long enough
2090 * that we won't make the old 4*rto = almost no time - whoops
2091 * reset mistake.
2092 *
2093 * Nope, it was not mistake. It is really desired behaviour
2094 * f.e. on http servers, when such sockets are useless, but
2095 * consume significant resources. Let's do it with special
2096 * linger2 option. --ANK
2097 */
2098
2099 if (sk->sk_state == TCP_FIN_WAIT2) {
2100 struct tcp_sock *tp = tcp_sk(sk);
2101 if (tp->linger2 < 0) {
2102 tcp_set_state(sk, TCP_CLOSE);
2103 tcp_send_active_reset(sk, GFP_ATOMIC);
2104 NET_INC_STATS_BH(sock_net(sk),
2105 LINUX_MIB_TCPABORTONLINGER);
2106 } else {
2107 const int tmo = tcp_fin_time(sk);
2108
2109 if (tmo > TCP_TIMEWAIT_LEN) {
2110 inet_csk_reset_keepalive_timer(sk,
2111 tmo - TCP_TIMEWAIT_LEN);
2112 } else {
2113 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2114 goto out;
2115 }
2116 }
2117 }
2118 if (sk->sk_state != TCP_CLOSE) {
2119 sk_mem_reclaim(sk);
2120 if (tcp_check_oom(sk, 0)) {
2121 tcp_set_state(sk, TCP_CLOSE);
2122 tcp_send_active_reset(sk, GFP_ATOMIC);
2123 NET_INC_STATS_BH(sock_net(sk),
2124 LINUX_MIB_TCPABORTONMEMORY);
2125 }
2126 }
2127
2128 if (sk->sk_state == TCP_CLOSE)
2129 inet_csk_destroy_sock(sk);
2130 /* Otherwise, socket is reprieved until protocol close. */
2131
2132 out:
2133 bh_unlock_sock(sk);
2134 local_bh_enable();
2135 sock_put(sk);
2136 }
2137 EXPORT_SYMBOL(tcp_close);
2138
2139 /* These states need RST on ABORT according to RFC793 */
2140
2141 static inline int tcp_need_reset(int state)
2142 {
2143 return (1 << state) &
2144 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2145 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2146 }
2147
2148 int tcp_disconnect(struct sock *sk, int flags)
2149 {
2150 struct inet_sock *inet = inet_sk(sk);
2151 struct inet_connection_sock *icsk = inet_csk(sk);
2152 struct tcp_sock *tp = tcp_sk(sk);
2153 int err = 0;
2154 int old_state = sk->sk_state;
2155
2156 if (old_state != TCP_CLOSE)
2157 tcp_set_state(sk, TCP_CLOSE);
2158
2159 /* ABORT function of RFC793 */
2160 if (old_state == TCP_LISTEN) {
2161 inet_csk_listen_stop(sk);
2162 } else if (unlikely(tp->repair)) {
2163 sk->sk_err = ECONNABORTED;
2164 } else if (tcp_need_reset(old_state) ||
2165 (tp->snd_nxt != tp->write_seq &&
2166 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2167 /* The last check adjusts for discrepancy of Linux wrt. RFC
2168 * states
2169 */
2170 tcp_send_active_reset(sk, gfp_any());
2171 sk->sk_err = ECONNRESET;
2172 } else if (old_state == TCP_SYN_SENT)
2173 sk->sk_err = ECONNRESET;
2174
2175 tcp_clear_xmit_timers(sk);
2176 __skb_queue_purge(&sk->sk_receive_queue);
2177 tcp_write_queue_purge(sk);
2178 __skb_queue_purge(&tp->out_of_order_queue);
2179 #ifdef CONFIG_NET_DMA
2180 __skb_queue_purge(&sk->sk_async_wait_queue);
2181 #endif
2182
2183 inet->inet_dport = 0;
2184
2185 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2186 inet_reset_saddr(sk);
2187
2188 sk->sk_shutdown = 0;
2189 sock_reset_flag(sk, SOCK_DONE);
2190 tp->srtt = 0;
2191 if ((tp->write_seq += tp->max_window + 2) == 0)
2192 tp->write_seq = 1;
2193 icsk->icsk_backoff = 0;
2194 tp->snd_cwnd = 2;
2195 icsk->icsk_probes_out = 0;
2196 tp->packets_out = 0;
2197 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2198 tp->snd_cwnd_cnt = 0;
2199 tp->bytes_acked = 0;
2200 tp->window_clamp = 0;
2201 tcp_set_ca_state(sk, TCP_CA_Open);
2202 tcp_clear_retrans(tp);
2203 inet_csk_delack_init(sk);
2204 tcp_init_send_head(sk);
2205 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2206 __sk_dst_reset(sk);
2207
2208 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2209
2210 sk->sk_error_report(sk);
2211 return err;
2212 }
2213 EXPORT_SYMBOL(tcp_disconnect);
2214
2215 static inline int tcp_can_repair_sock(struct sock *sk)
2216 {
2217 return capable(CAP_NET_ADMIN) &&
2218 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
2219 }
2220
2221 /*
2222 * Socket option code for TCP.
2223 */
2224 static int do_tcp_setsockopt(struct sock *sk, int level,
2225 int optname, char __user *optval, unsigned int optlen)
2226 {
2227 struct tcp_sock *tp = tcp_sk(sk);
2228 struct inet_connection_sock *icsk = inet_csk(sk);
2229 int val;
2230 int err = 0;
2231
2232 /* These are data/string values, all the others are ints */
2233 switch (optname) {
2234 case TCP_CONGESTION: {
2235 char name[TCP_CA_NAME_MAX];
2236
2237 if (optlen < 1)
2238 return -EINVAL;
2239
2240 val = strncpy_from_user(name, optval,
2241 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2242 if (val < 0)
2243 return -EFAULT;
2244 name[val] = 0;
2245
2246 lock_sock(sk);
2247 err = tcp_set_congestion_control(sk, name);
2248 release_sock(sk);
2249 return err;
2250 }
2251 case TCP_COOKIE_TRANSACTIONS: {
2252 struct tcp_cookie_transactions ctd;
2253 struct tcp_cookie_values *cvp = NULL;
2254
2255 if (sizeof(ctd) > optlen)
2256 return -EINVAL;
2257 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2258 return -EFAULT;
2259
2260 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2261 ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2262 return -EINVAL;
2263
2264 if (ctd.tcpct_cookie_desired == 0) {
2265 /* default to global value */
2266 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2267 ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2268 ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2269 return -EINVAL;
2270 }
2271
2272 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2273 /* Supercedes all other values */
2274 lock_sock(sk);
2275 if (tp->cookie_values != NULL) {
2276 kref_put(&tp->cookie_values->kref,
2277 tcp_cookie_values_release);
2278 tp->cookie_values = NULL;
2279 }
2280 tp->rx_opt.cookie_in_always = 0; /* false */
2281 tp->rx_opt.cookie_out_never = 1; /* true */
2282 release_sock(sk);
2283 return err;
2284 }
2285
2286 /* Allocate ancillary memory before locking.
2287 */
2288 if (ctd.tcpct_used > 0 ||
2289 (tp->cookie_values == NULL &&
2290 (sysctl_tcp_cookie_size > 0 ||
2291 ctd.tcpct_cookie_desired > 0 ||
2292 ctd.tcpct_s_data_desired > 0))) {
2293 cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2294 GFP_KERNEL);
2295 if (cvp == NULL)
2296 return -ENOMEM;
2297
2298 kref_init(&cvp->kref);
2299 }
2300 lock_sock(sk);
2301 tp->rx_opt.cookie_in_always =
2302 (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2303 tp->rx_opt.cookie_out_never = 0; /* false */
2304
2305 if (tp->cookie_values != NULL) {
2306 if (cvp != NULL) {
2307 /* Changed values are recorded by a changed
2308 * pointer, ensuring the cookie will differ,
2309 * without separately hashing each value later.
2310 */
2311 kref_put(&tp->cookie_values->kref,
2312 tcp_cookie_values_release);
2313 } else {
2314 cvp = tp->cookie_values;
2315 }
2316 }
2317
2318 if (cvp != NULL) {
2319 cvp->cookie_desired = ctd.tcpct_cookie_desired;
2320
2321 if (ctd.tcpct_used > 0) {
2322 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2323 ctd.tcpct_used);
2324 cvp->s_data_desired = ctd.tcpct_used;
2325 cvp->s_data_constant = 1; /* true */
2326 } else {
2327 /* No constant payload data. */
2328 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2329 cvp->s_data_constant = 0; /* false */
2330 }
2331
2332 tp->cookie_values = cvp;
2333 }
2334 release_sock(sk);
2335 return err;
2336 }
2337 default:
2338 /* fallthru */
2339 break;
2340 }
2341
2342 if (optlen < sizeof(int))
2343 return -EINVAL;
2344
2345 if (get_user(val, (int __user *)optval))
2346 return -EFAULT;
2347
2348 lock_sock(sk);
2349
2350 switch (optname) {
2351 case TCP_MAXSEG:
2352 /* Values greater than interface MTU won't take effect. However
2353 * at the point when this call is done we typically don't yet
2354 * know which interface is going to be used */
2355 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2356 err = -EINVAL;
2357 break;
2358 }
2359 tp->rx_opt.user_mss = val;
2360 break;
2361
2362 case TCP_NODELAY:
2363 if (val) {
2364 /* TCP_NODELAY is weaker than TCP_CORK, so that
2365 * this option on corked socket is remembered, but
2366 * it is not activated until cork is cleared.
2367 *
2368 * However, when TCP_NODELAY is set we make
2369 * an explicit push, which overrides even TCP_CORK
2370 * for currently queued segments.
2371 */
2372 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2373 tcp_push_pending_frames(sk);
2374 } else {
2375 tp->nonagle &= ~TCP_NAGLE_OFF;
2376 }
2377 break;
2378
2379 case TCP_THIN_LINEAR_TIMEOUTS:
2380 if (val < 0 || val > 1)
2381 err = -EINVAL;
2382 else
2383 tp->thin_lto = val;
2384 break;
2385
2386 case TCP_THIN_DUPACK:
2387 if (val < 0 || val > 1)
2388 err = -EINVAL;
2389 else
2390 tp->thin_dupack = val;
2391 break;
2392
2393 case TCP_REPAIR:
2394 if (!tcp_can_repair_sock(sk))
2395 err = -EPERM;
2396 else if (val == 1) {
2397 tp->repair = 1;
2398 sk->sk_reuse = SK_FORCE_REUSE;
2399 tp->repair_queue = TCP_NO_QUEUE;
2400 } else if (val == 0) {
2401 tp->repair = 0;
2402 sk->sk_reuse = SK_NO_REUSE;
2403 tcp_send_window_probe(sk);
2404 } else
2405 err = -EINVAL;
2406
2407 break;
2408
2409 case TCP_REPAIR_QUEUE:
2410 if (!tp->repair)
2411 err = -EPERM;
2412 else if (val < TCP_QUEUES_NR)
2413 tp->repair_queue = val;
2414 else
2415 err = -EINVAL;
2416 break;
2417
2418 case TCP_QUEUE_SEQ:
2419 if (sk->sk_state != TCP_CLOSE)
2420 err = -EPERM;
2421 else if (tp->repair_queue == TCP_SEND_QUEUE)
2422 tp->write_seq = val;
2423 else if (tp->repair_queue == TCP_RECV_QUEUE)
2424 tp->rcv_nxt = val;
2425 else
2426 err = -EINVAL;
2427 break;
2428
2429 case TCP_CORK:
2430 /* When set indicates to always queue non-full frames.
2431 * Later the user clears this option and we transmit
2432 * any pending partial frames in the queue. This is
2433 * meant to be used alongside sendfile() to get properly
2434 * filled frames when the user (for example) must write
2435 * out headers with a write() call first and then use
2436 * sendfile to send out the data parts.
2437 *
2438 * TCP_CORK can be set together with TCP_NODELAY and it is
2439 * stronger than TCP_NODELAY.
2440 */
2441 if (val) {
2442 tp->nonagle |= TCP_NAGLE_CORK;
2443 } else {
2444 tp->nonagle &= ~TCP_NAGLE_CORK;
2445 if (tp->nonagle&TCP_NAGLE_OFF)
2446 tp->nonagle |= TCP_NAGLE_PUSH;
2447 tcp_push_pending_frames(sk);
2448 }
2449 break;
2450
2451 case TCP_KEEPIDLE:
2452 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2453 err = -EINVAL;
2454 else {
2455 tp->keepalive_time = val * HZ;
2456 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2457 !((1 << sk->sk_state) &
2458 (TCPF_CLOSE | TCPF_LISTEN))) {
2459 u32 elapsed = keepalive_time_elapsed(tp);
2460 if (tp->keepalive_time > elapsed)
2461 elapsed = tp->keepalive_time - elapsed;
2462 else
2463 elapsed = 0;
2464 inet_csk_reset_keepalive_timer(sk, elapsed);
2465 }
2466 }
2467 break;
2468 case TCP_KEEPINTVL:
2469 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2470 err = -EINVAL;
2471 else
2472 tp->keepalive_intvl = val * HZ;
2473 break;
2474 case TCP_KEEPCNT:
2475 if (val < 1 || val > MAX_TCP_KEEPCNT)
2476 err = -EINVAL;
2477 else
2478 tp->keepalive_probes = val;
2479 break;
2480 case TCP_SYNCNT:
2481 if (val < 1 || val > MAX_TCP_SYNCNT)
2482 err = -EINVAL;
2483 else
2484 icsk->icsk_syn_retries = val;
2485 break;
2486
2487 case TCP_LINGER2:
2488 if (val < 0)
2489 tp->linger2 = -1;
2490 else if (val > sysctl_tcp_fin_timeout / HZ)
2491 tp->linger2 = 0;
2492 else
2493 tp->linger2 = val * HZ;
2494 break;
2495
2496 case TCP_DEFER_ACCEPT:
2497 /* Translate value in seconds to number of retransmits */
2498 icsk->icsk_accept_queue.rskq_defer_accept =
2499 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2500 TCP_RTO_MAX / HZ);
2501 break;
2502
2503 case TCP_WINDOW_CLAMP:
2504 if (!val) {
2505 if (sk->sk_state != TCP_CLOSE) {
2506 err = -EINVAL;
2507 break;
2508 }
2509 tp->window_clamp = 0;
2510 } else
2511 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2512 SOCK_MIN_RCVBUF / 2 : val;
2513 break;
2514
2515 case TCP_QUICKACK:
2516 if (!val) {
2517 icsk->icsk_ack.pingpong = 1;
2518 } else {
2519 icsk->icsk_ack.pingpong = 0;
2520 if ((1 << sk->sk_state) &
2521 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2522 inet_csk_ack_scheduled(sk)) {
2523 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2524 tcp_cleanup_rbuf(sk, 1);
2525 if (!(val & 1))
2526 icsk->icsk_ack.pingpong = 1;
2527 }
2528 }
2529 break;
2530
2531 #ifdef CONFIG_TCP_MD5SIG
2532 case TCP_MD5SIG:
2533 /* Read the IP->Key mappings from userspace */
2534 err = tp->af_specific->md5_parse(sk, optval, optlen);
2535 break;
2536 #endif
2537 case TCP_USER_TIMEOUT:
2538 /* Cap the max timeout in ms TCP will retry/retrans
2539 * before giving up and aborting (ETIMEDOUT) a connection.
2540 */
2541 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2542 break;
2543 default:
2544 err = -ENOPROTOOPT;
2545 break;
2546 }
2547
2548 release_sock(sk);
2549 return err;
2550 }
2551
2552 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2553 unsigned int optlen)
2554 {
2555 const struct inet_connection_sock *icsk = inet_csk(sk);
2556
2557 if (level != SOL_TCP)
2558 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2559 optval, optlen);
2560 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2561 }
2562 EXPORT_SYMBOL(tcp_setsockopt);
2563
2564 #ifdef CONFIG_COMPAT
2565 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2566 char __user *optval, unsigned int optlen)
2567 {
2568 if (level != SOL_TCP)
2569 return inet_csk_compat_setsockopt(sk, level, optname,
2570 optval, optlen);
2571 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2572 }
2573 EXPORT_SYMBOL(compat_tcp_setsockopt);
2574 #endif
2575
2576 /* Return information about state of tcp endpoint in API format. */
2577 void tcp_get_info(const struct sock *sk, struct tcp_info *info)
2578 {
2579 const struct tcp_sock *tp = tcp_sk(sk);
2580 const struct inet_connection_sock *icsk = inet_csk(sk);
2581 u32 now = tcp_time_stamp;
2582
2583 memset(info, 0, sizeof(*info));
2584
2585 info->tcpi_state = sk->sk_state;
2586 info->tcpi_ca_state = icsk->icsk_ca_state;
2587 info->tcpi_retransmits = icsk->icsk_retransmits;
2588 info->tcpi_probes = icsk->icsk_probes_out;
2589 info->tcpi_backoff = icsk->icsk_backoff;
2590
2591 if (tp->rx_opt.tstamp_ok)
2592 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2593 if (tcp_is_sack(tp))
2594 info->tcpi_options |= TCPI_OPT_SACK;
2595 if (tp->rx_opt.wscale_ok) {
2596 info->tcpi_options |= TCPI_OPT_WSCALE;
2597 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2598 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2599 }
2600
2601 if (tp->ecn_flags & TCP_ECN_OK)
2602 info->tcpi_options |= TCPI_OPT_ECN;
2603 if (tp->ecn_flags & TCP_ECN_SEEN)
2604 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2605
2606 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2607 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2608 info->tcpi_snd_mss = tp->mss_cache;
2609 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2610
2611 if (sk->sk_state == TCP_LISTEN) {
2612 info->tcpi_unacked = sk->sk_ack_backlog;
2613 info->tcpi_sacked = sk->sk_max_ack_backlog;
2614 } else {
2615 info->tcpi_unacked = tp->packets_out;
2616 info->tcpi_sacked = tp->sacked_out;
2617 }
2618 info->tcpi_lost = tp->lost_out;
2619 info->tcpi_retrans = tp->retrans_out;
2620 info->tcpi_fackets = tp->fackets_out;
2621
2622 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2623 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2624 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2625
2626 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2627 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2628 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2629 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2630 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2631 info->tcpi_snd_cwnd = tp->snd_cwnd;
2632 info->tcpi_advmss = tp->advmss;
2633 info->tcpi_reordering = tp->reordering;
2634
2635 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2636 info->tcpi_rcv_space = tp->rcvq_space.space;
2637
2638 info->tcpi_total_retrans = tp->total_retrans;
2639 }
2640 EXPORT_SYMBOL_GPL(tcp_get_info);
2641
2642 static int do_tcp_getsockopt(struct sock *sk, int level,
2643 int optname, char __user *optval, int __user *optlen)
2644 {
2645 struct inet_connection_sock *icsk = inet_csk(sk);
2646 struct tcp_sock *tp = tcp_sk(sk);
2647 int val, len;
2648
2649 if (get_user(len, optlen))
2650 return -EFAULT;
2651
2652 len = min_t(unsigned int, len, sizeof(int));
2653
2654 if (len < 0)
2655 return -EINVAL;
2656
2657 switch (optname) {
2658 case TCP_MAXSEG:
2659 val = tp->mss_cache;
2660 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2661 val = tp->rx_opt.user_mss;
2662 break;
2663 case TCP_NODELAY:
2664 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2665 break;
2666 case TCP_CORK:
2667 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2668 break;
2669 case TCP_KEEPIDLE:
2670 val = keepalive_time_when(tp) / HZ;
2671 break;
2672 case TCP_KEEPINTVL:
2673 val = keepalive_intvl_when(tp) / HZ;
2674 break;
2675 case TCP_KEEPCNT:
2676 val = keepalive_probes(tp);
2677 break;
2678 case TCP_SYNCNT:
2679 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2680 break;
2681 case TCP_LINGER2:
2682 val = tp->linger2;
2683 if (val >= 0)
2684 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2685 break;
2686 case TCP_DEFER_ACCEPT:
2687 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2688 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2689 break;
2690 case TCP_WINDOW_CLAMP:
2691 val = tp->window_clamp;
2692 break;
2693 case TCP_INFO: {
2694 struct tcp_info info;
2695
2696 if (get_user(len, optlen))
2697 return -EFAULT;
2698
2699 tcp_get_info(sk, &info);
2700
2701 len = min_t(unsigned int, len, sizeof(info));
2702 if (put_user(len, optlen))
2703 return -EFAULT;
2704 if (copy_to_user(optval, &info, len))
2705 return -EFAULT;
2706 return 0;
2707 }
2708 case TCP_QUICKACK:
2709 val = !icsk->icsk_ack.pingpong;
2710 break;
2711
2712 case TCP_CONGESTION:
2713 if (get_user(len, optlen))
2714 return -EFAULT;
2715 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2716 if (put_user(len, optlen))
2717 return -EFAULT;
2718 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2719 return -EFAULT;
2720 return 0;
2721
2722 case TCP_COOKIE_TRANSACTIONS: {
2723 struct tcp_cookie_transactions ctd;
2724 struct tcp_cookie_values *cvp = tp->cookie_values;
2725
2726 if (get_user(len, optlen))
2727 return -EFAULT;
2728 if (len < sizeof(ctd))
2729 return -EINVAL;
2730
2731 memset(&ctd, 0, sizeof(ctd));
2732 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2733 TCP_COOKIE_IN_ALWAYS : 0)
2734 | (tp->rx_opt.cookie_out_never ?
2735 TCP_COOKIE_OUT_NEVER : 0);
2736
2737 if (cvp != NULL) {
2738 ctd.tcpct_flags |= (cvp->s_data_in ?
2739 TCP_S_DATA_IN : 0)
2740 | (cvp->s_data_out ?
2741 TCP_S_DATA_OUT : 0);
2742
2743 ctd.tcpct_cookie_desired = cvp->cookie_desired;
2744 ctd.tcpct_s_data_desired = cvp->s_data_desired;
2745
2746 memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2747 cvp->cookie_pair_size);
2748 ctd.tcpct_used = cvp->cookie_pair_size;
2749 }
2750
2751 if (put_user(sizeof(ctd), optlen))
2752 return -EFAULT;
2753 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2754 return -EFAULT;
2755 return 0;
2756 }
2757 case TCP_THIN_LINEAR_TIMEOUTS:
2758 val = tp->thin_lto;
2759 break;
2760 case TCP_THIN_DUPACK:
2761 val = tp->thin_dupack;
2762 break;
2763
2764 case TCP_REPAIR:
2765 val = tp->repair;
2766 break;
2767
2768 case TCP_REPAIR_QUEUE:
2769 if (tp->repair)
2770 val = tp->repair_queue;
2771 else
2772 return -EINVAL;
2773 break;
2774
2775 case TCP_QUEUE_SEQ:
2776 if (tp->repair_queue == TCP_SEND_QUEUE)
2777 val = tp->write_seq;
2778 else if (tp->repair_queue == TCP_RECV_QUEUE)
2779 val = tp->rcv_nxt;
2780 else
2781 return -EINVAL;
2782 break;
2783
2784 case TCP_USER_TIMEOUT:
2785 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2786 break;
2787 default:
2788 return -ENOPROTOOPT;
2789 }
2790
2791 if (put_user(len, optlen))
2792 return -EFAULT;
2793 if (copy_to_user(optval, &val, len))
2794 return -EFAULT;
2795 return 0;
2796 }
2797
2798 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2799 int __user *optlen)
2800 {
2801 struct inet_connection_sock *icsk = inet_csk(sk);
2802
2803 if (level != SOL_TCP)
2804 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2805 optval, optlen);
2806 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2807 }
2808 EXPORT_SYMBOL(tcp_getsockopt);
2809
2810 #ifdef CONFIG_COMPAT
2811 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2812 char __user *optval, int __user *optlen)
2813 {
2814 if (level != SOL_TCP)
2815 return inet_csk_compat_getsockopt(sk, level, optname,
2816 optval, optlen);
2817 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2818 }
2819 EXPORT_SYMBOL(compat_tcp_getsockopt);
2820 #endif
2821
2822 struct sk_buff *tcp_tso_segment(struct sk_buff *skb,
2823 netdev_features_t features)
2824 {
2825 struct sk_buff *segs = ERR_PTR(-EINVAL);
2826 struct tcphdr *th;
2827 unsigned int thlen;
2828 unsigned int seq;
2829 __be32 delta;
2830 unsigned int oldlen;
2831 unsigned int mss;
2832
2833 if (!pskb_may_pull(skb, sizeof(*th)))
2834 goto out;
2835
2836 th = tcp_hdr(skb);
2837 thlen = th->doff * 4;
2838 if (thlen < sizeof(*th))
2839 goto out;
2840
2841 if (!pskb_may_pull(skb, thlen))
2842 goto out;
2843
2844 oldlen = (u16)~skb->len;
2845 __skb_pull(skb, thlen);
2846
2847 mss = skb_shinfo(skb)->gso_size;
2848 if (unlikely(skb->len <= mss))
2849 goto out;
2850
2851 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2852 /* Packet is from an untrusted source, reset gso_segs. */
2853 int type = skb_shinfo(skb)->gso_type;
2854
2855 if (unlikely(type &
2856 ~(SKB_GSO_TCPV4 |
2857 SKB_GSO_DODGY |
2858 SKB_GSO_TCP_ECN |
2859 SKB_GSO_TCPV6 |
2860 0) ||
2861 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2862 goto out;
2863
2864 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2865
2866 segs = NULL;
2867 goto out;
2868 }
2869
2870 segs = skb_segment(skb, features);
2871 if (IS_ERR(segs))
2872 goto out;
2873
2874 delta = htonl(oldlen + (thlen + mss));
2875
2876 skb = segs;
2877 th = tcp_hdr(skb);
2878 seq = ntohl(th->seq);
2879
2880 do {
2881 th->fin = th->psh = 0;
2882
2883 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2884 (__force u32)delta));
2885 if (skb->ip_summed != CHECKSUM_PARTIAL)
2886 th->check =
2887 csum_fold(csum_partial(skb_transport_header(skb),
2888 thlen, skb->csum));
2889
2890 seq += mss;
2891 skb = skb->next;
2892 th = tcp_hdr(skb);
2893
2894 th->seq = htonl(seq);
2895 th->cwr = 0;
2896 } while (skb->next);
2897
2898 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2899 skb->data_len);
2900 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2901 (__force u32)delta));
2902 if (skb->ip_summed != CHECKSUM_PARTIAL)
2903 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2904 thlen, skb->csum));
2905
2906 out:
2907 return segs;
2908 }
2909 EXPORT_SYMBOL(tcp_tso_segment);
2910
2911 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2912 {
2913 struct sk_buff **pp = NULL;
2914 struct sk_buff *p;
2915 struct tcphdr *th;
2916 struct tcphdr *th2;
2917 unsigned int len;
2918 unsigned int thlen;
2919 __be32 flags;
2920 unsigned int mss = 1;
2921 unsigned int hlen;
2922 unsigned int off;
2923 int flush = 1;
2924 int i;
2925
2926 off = skb_gro_offset(skb);
2927 hlen = off + sizeof(*th);
2928 th = skb_gro_header_fast(skb, off);
2929 if (skb_gro_header_hard(skb, hlen)) {
2930 th = skb_gro_header_slow(skb, hlen, off);
2931 if (unlikely(!th))
2932 goto out;
2933 }
2934
2935 thlen = th->doff * 4;
2936 if (thlen < sizeof(*th))
2937 goto out;
2938
2939 hlen = off + thlen;
2940 if (skb_gro_header_hard(skb, hlen)) {
2941 th = skb_gro_header_slow(skb, hlen, off);
2942 if (unlikely(!th))
2943 goto out;
2944 }
2945
2946 skb_gro_pull(skb, thlen);
2947
2948 len = skb_gro_len(skb);
2949 flags = tcp_flag_word(th);
2950
2951 for (; (p = *head); head = &p->next) {
2952 if (!NAPI_GRO_CB(p)->same_flow)
2953 continue;
2954
2955 th2 = tcp_hdr(p);
2956
2957 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2958 NAPI_GRO_CB(p)->same_flow = 0;
2959 continue;
2960 }
2961
2962 goto found;
2963 }
2964
2965 goto out_check_final;
2966
2967 found:
2968 flush = NAPI_GRO_CB(p)->flush;
2969 flush |= (__force int)(flags & TCP_FLAG_CWR);
2970 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
2971 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
2972 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
2973 for (i = sizeof(*th); i < thlen; i += 4)
2974 flush |= *(u32 *)((u8 *)th + i) ^
2975 *(u32 *)((u8 *)th2 + i);
2976
2977 mss = skb_shinfo(p)->gso_size;
2978
2979 flush |= (len - 1) >= mss;
2980 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2981
2982 if (flush || skb_gro_receive(head, skb)) {
2983 mss = 1;
2984 goto out_check_final;
2985 }
2986
2987 p = *head;
2988 th2 = tcp_hdr(p);
2989 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2990
2991 out_check_final:
2992 flush = len < mss;
2993 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
2994 TCP_FLAG_RST | TCP_FLAG_SYN |
2995 TCP_FLAG_FIN));
2996
2997 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2998 pp = head;
2999
3000 out:
3001 NAPI_GRO_CB(skb)->flush |= flush;
3002
3003 return pp;
3004 }
3005 EXPORT_SYMBOL(tcp_gro_receive);
3006
3007 int tcp_gro_complete(struct sk_buff *skb)
3008 {
3009 struct tcphdr *th = tcp_hdr(skb);
3010
3011 skb->csum_start = skb_transport_header(skb) - skb->head;
3012 skb->csum_offset = offsetof(struct tcphdr, check);
3013 skb->ip_summed = CHECKSUM_PARTIAL;
3014
3015 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
3016
3017 if (th->cwr)
3018 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
3019
3020 return 0;
3021 }
3022 EXPORT_SYMBOL(tcp_gro_complete);
3023
3024 #ifdef CONFIG_TCP_MD5SIG
3025 static unsigned long tcp_md5sig_users;
3026 static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool;
3027 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
3028
3029 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool)
3030 {
3031 int cpu;
3032
3033 for_each_possible_cpu(cpu) {
3034 struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu);
3035
3036 if (p->md5_desc.tfm)
3037 crypto_free_hash(p->md5_desc.tfm);
3038 }
3039 free_percpu(pool);
3040 }
3041
3042 void tcp_free_md5sig_pool(void)
3043 {
3044 struct tcp_md5sig_pool __percpu *pool = NULL;
3045
3046 spin_lock_bh(&tcp_md5sig_pool_lock);
3047 if (--tcp_md5sig_users == 0) {
3048 pool = tcp_md5sig_pool;
3049 tcp_md5sig_pool = NULL;
3050 }
3051 spin_unlock_bh(&tcp_md5sig_pool_lock);
3052 if (pool)
3053 __tcp_free_md5sig_pool(pool);
3054 }
3055 EXPORT_SYMBOL(tcp_free_md5sig_pool);
3056
3057 static struct tcp_md5sig_pool __percpu *
3058 __tcp_alloc_md5sig_pool(struct sock *sk)
3059 {
3060 int cpu;
3061 struct tcp_md5sig_pool __percpu *pool;
3062
3063 pool = alloc_percpu(struct tcp_md5sig_pool);
3064 if (!pool)
3065 return NULL;
3066
3067 for_each_possible_cpu(cpu) {
3068 struct crypto_hash *hash;
3069
3070 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
3071 if (!hash || IS_ERR(hash))
3072 goto out_free;
3073
3074 per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash;
3075 }
3076 return pool;
3077 out_free:
3078 __tcp_free_md5sig_pool(pool);
3079 return NULL;
3080 }
3081
3082 struct tcp_md5sig_pool __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
3083 {
3084 struct tcp_md5sig_pool __percpu *pool;
3085 int alloc = 0;
3086
3087 retry:
3088 spin_lock_bh(&tcp_md5sig_pool_lock);
3089 pool = tcp_md5sig_pool;
3090 if (tcp_md5sig_users++ == 0) {
3091 alloc = 1;
3092 spin_unlock_bh(&tcp_md5sig_pool_lock);
3093 } else if (!pool) {
3094 tcp_md5sig_users--;
3095 spin_unlock_bh(&tcp_md5sig_pool_lock);
3096 cpu_relax();
3097 goto retry;
3098 } else
3099 spin_unlock_bh(&tcp_md5sig_pool_lock);
3100
3101 if (alloc) {
3102 /* we cannot hold spinlock here because this may sleep. */
3103 struct tcp_md5sig_pool __percpu *p;
3104
3105 p = __tcp_alloc_md5sig_pool(sk);
3106 spin_lock_bh(&tcp_md5sig_pool_lock);
3107 if (!p) {
3108 tcp_md5sig_users--;
3109 spin_unlock_bh(&tcp_md5sig_pool_lock);
3110 return NULL;
3111 }
3112 pool = tcp_md5sig_pool;
3113 if (pool) {
3114 /* oops, it has already been assigned. */
3115 spin_unlock_bh(&tcp_md5sig_pool_lock);
3116 __tcp_free_md5sig_pool(p);
3117 } else {
3118 tcp_md5sig_pool = pool = p;
3119 spin_unlock_bh(&tcp_md5sig_pool_lock);
3120 }
3121 }
3122 return pool;
3123 }
3124 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
3125
3126
3127 /**
3128 * tcp_get_md5sig_pool - get md5sig_pool for this user
3129 *
3130 * We use percpu structure, so if we succeed, we exit with preemption
3131 * and BH disabled, to make sure another thread or softirq handling
3132 * wont try to get same context.
3133 */
3134 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
3135 {
3136 struct tcp_md5sig_pool __percpu *p;
3137
3138 local_bh_disable();
3139
3140 spin_lock(&tcp_md5sig_pool_lock);
3141 p = tcp_md5sig_pool;
3142 if (p)
3143 tcp_md5sig_users++;
3144 spin_unlock(&tcp_md5sig_pool_lock);
3145
3146 if (p)
3147 return this_cpu_ptr(p);
3148
3149 local_bh_enable();
3150 return NULL;
3151 }
3152 EXPORT_SYMBOL(tcp_get_md5sig_pool);
3153
3154 void tcp_put_md5sig_pool(void)
3155 {
3156 local_bh_enable();
3157 tcp_free_md5sig_pool();
3158 }
3159 EXPORT_SYMBOL(tcp_put_md5sig_pool);
3160
3161 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3162 const struct tcphdr *th)
3163 {
3164 struct scatterlist sg;
3165 struct tcphdr hdr;
3166 int err;
3167
3168 /* We are not allowed to change tcphdr, make a local copy */
3169 memcpy(&hdr, th, sizeof(hdr));
3170 hdr.check = 0;
3171
3172 /* options aren't included in the hash */
3173 sg_init_one(&sg, &hdr, sizeof(hdr));
3174 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
3175 return err;
3176 }
3177 EXPORT_SYMBOL(tcp_md5_hash_header);
3178
3179 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3180 const struct sk_buff *skb, unsigned int header_len)
3181 {
3182 struct scatterlist sg;
3183 const struct tcphdr *tp = tcp_hdr(skb);
3184 struct hash_desc *desc = &hp->md5_desc;
3185 unsigned int i;
3186 const unsigned int head_data_len = skb_headlen(skb) > header_len ?
3187 skb_headlen(skb) - header_len : 0;
3188 const struct skb_shared_info *shi = skb_shinfo(skb);
3189 struct sk_buff *frag_iter;
3190
3191 sg_init_table(&sg, 1);
3192
3193 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3194 if (crypto_hash_update(desc, &sg, head_data_len))
3195 return 1;
3196
3197 for (i = 0; i < shi->nr_frags; ++i) {
3198 const struct skb_frag_struct *f = &shi->frags[i];
3199 struct page *page = skb_frag_page(f);
3200 sg_set_page(&sg, page, skb_frag_size(f), f->page_offset);
3201 if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3202 return 1;
3203 }
3204
3205 skb_walk_frags(skb, frag_iter)
3206 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3207 return 1;
3208
3209 return 0;
3210 }
3211 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3212
3213 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3214 {
3215 struct scatterlist sg;
3216
3217 sg_init_one(&sg, key->key, key->keylen);
3218 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3219 }
3220 EXPORT_SYMBOL(tcp_md5_hash_key);
3221
3222 #endif
3223
3224 /**
3225 * Each Responder maintains up to two secret values concurrently for
3226 * efficient secret rollover. Each secret value has 4 states:
3227 *
3228 * Generating. (tcp_secret_generating != tcp_secret_primary)
3229 * Generates new Responder-Cookies, but not yet used for primary
3230 * verification. This is a short-term state, typically lasting only
3231 * one round trip time (RTT).
3232 *
3233 * Primary. (tcp_secret_generating == tcp_secret_primary)
3234 * Used both for generation and primary verification.
3235 *
3236 * Retiring. (tcp_secret_retiring != tcp_secret_secondary)
3237 * Used for verification, until the first failure that can be
3238 * verified by the newer Generating secret. At that time, this
3239 * cookie's state is changed to Secondary, and the Generating
3240 * cookie's state is changed to Primary. This is a short-term state,
3241 * typically lasting only one round trip time (RTT).
3242 *
3243 * Secondary. (tcp_secret_retiring == tcp_secret_secondary)
3244 * Used for secondary verification, after primary verification
3245 * failures. This state lasts no more than twice the Maximum Segment
3246 * Lifetime (2MSL). Then, the secret is discarded.
3247 */
3248 struct tcp_cookie_secret {
3249 /* The secret is divided into two parts. The digest part is the
3250 * equivalent of previously hashing a secret and saving the state,
3251 * and serves as an initialization vector (IV). The message part
3252 * serves as the trailing secret.
3253 */
3254 u32 secrets[COOKIE_WORKSPACE_WORDS];
3255 unsigned long expires;
3256 };
3257
3258 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3259 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3260 #define TCP_SECRET_LIFE (HZ * 600)
3261
3262 static struct tcp_cookie_secret tcp_secret_one;
3263 static struct tcp_cookie_secret tcp_secret_two;
3264
3265 /* Essentially a circular list, without dynamic allocation. */
3266 static struct tcp_cookie_secret *tcp_secret_generating;
3267 static struct tcp_cookie_secret *tcp_secret_primary;
3268 static struct tcp_cookie_secret *tcp_secret_retiring;
3269 static struct tcp_cookie_secret *tcp_secret_secondary;
3270
3271 static DEFINE_SPINLOCK(tcp_secret_locker);
3272
3273 /* Select a pseudo-random word in the cookie workspace.
3274 */
3275 static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3276 {
3277 return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3278 }
3279
3280 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3281 * Called in softirq context.
3282 * Returns: 0 for success.
3283 */
3284 int tcp_cookie_generator(u32 *bakery)
3285 {
3286 unsigned long jiffy = jiffies;
3287
3288 if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3289 spin_lock_bh(&tcp_secret_locker);
3290 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3291 /* refreshed by another */
3292 memcpy(bakery,
3293 &tcp_secret_generating->secrets[0],
3294 COOKIE_WORKSPACE_WORDS);
3295 } else {
3296 /* still needs refreshing */
3297 get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3298
3299 /* The first time, paranoia assumes that the
3300 * randomization function isn't as strong. But,
3301 * this secret initialization is delayed until
3302 * the last possible moment (packet arrival).
3303 * Although that time is observable, it is
3304 * unpredictably variable. Mash in the most
3305 * volatile clock bits available, and expire the
3306 * secret extra quickly.
3307 */
3308 if (unlikely(tcp_secret_primary->expires ==
3309 tcp_secret_secondary->expires)) {
3310 struct timespec tv;
3311
3312 getnstimeofday(&tv);
3313 bakery[COOKIE_DIGEST_WORDS+0] ^=
3314 (u32)tv.tv_nsec;
3315
3316 tcp_secret_secondary->expires = jiffy
3317 + TCP_SECRET_1MSL
3318 + (0x0f & tcp_cookie_work(bakery, 0));
3319 } else {
3320 tcp_secret_secondary->expires = jiffy
3321 + TCP_SECRET_LIFE
3322 + (0xff & tcp_cookie_work(bakery, 1));
3323 tcp_secret_primary->expires = jiffy
3324 + TCP_SECRET_2MSL
3325 + (0x1f & tcp_cookie_work(bakery, 2));
3326 }
3327 memcpy(&tcp_secret_secondary->secrets[0],
3328 bakery, COOKIE_WORKSPACE_WORDS);
3329
3330 rcu_assign_pointer(tcp_secret_generating,
3331 tcp_secret_secondary);
3332 rcu_assign_pointer(tcp_secret_retiring,
3333 tcp_secret_primary);
3334 /*
3335 * Neither call_rcu() nor synchronize_rcu() needed.
3336 * Retiring data is not freed. It is replaced after
3337 * further (locked) pointer updates, and a quiet time
3338 * (minimum 1MSL, maximum LIFE - 2MSL).
3339 */
3340 }
3341 spin_unlock_bh(&tcp_secret_locker);
3342 } else {
3343 rcu_read_lock_bh();
3344 memcpy(bakery,
3345 &rcu_dereference(tcp_secret_generating)->secrets[0],
3346 COOKIE_WORKSPACE_WORDS);
3347 rcu_read_unlock_bh();
3348 }
3349 return 0;
3350 }
3351 EXPORT_SYMBOL(tcp_cookie_generator);
3352
3353 void tcp_done(struct sock *sk)
3354 {
3355 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3356 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3357
3358 tcp_set_state(sk, TCP_CLOSE);
3359 tcp_clear_xmit_timers(sk);
3360
3361 sk->sk_shutdown = SHUTDOWN_MASK;
3362
3363 if (!sock_flag(sk, SOCK_DEAD))
3364 sk->sk_state_change(sk);
3365 else
3366 inet_csk_destroy_sock(sk);
3367 }
3368 EXPORT_SYMBOL_GPL(tcp_done);
3369
3370 extern struct tcp_congestion_ops tcp_reno;
3371
3372 static __initdata unsigned long thash_entries;
3373 static int __init set_thash_entries(char *str)
3374 {
3375 if (!str)
3376 return 0;
3377 thash_entries = simple_strtoul(str, &str, 0);
3378 return 1;
3379 }
3380 __setup("thash_entries=", set_thash_entries);
3381
3382 void tcp_init_mem(struct net *net)
3383 {
3384 unsigned long limit = nr_free_buffer_pages() / 8;
3385 limit = max(limit, 128UL);
3386 net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3;
3387 net->ipv4.sysctl_tcp_mem[1] = limit;
3388 net->ipv4.sysctl_tcp_mem[2] = net->ipv4.sysctl_tcp_mem[0] * 2;
3389 }
3390
3391 void __init tcp_init(void)
3392 {
3393 struct sk_buff *skb = NULL;
3394 unsigned long limit;
3395 int max_share, cnt;
3396 unsigned int i;
3397 unsigned long jiffy = jiffies;
3398
3399 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3400
3401 percpu_counter_init(&tcp_sockets_allocated, 0);
3402 percpu_counter_init(&tcp_orphan_count, 0);
3403 tcp_hashinfo.bind_bucket_cachep =
3404 kmem_cache_create("tcp_bind_bucket",
3405 sizeof(struct inet_bind_bucket), 0,
3406 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3407
3408 /* Size and allocate the main established and bind bucket
3409 * hash tables.
3410 *
3411 * The methodology is similar to that of the buffer cache.
3412 */
3413 tcp_hashinfo.ehash =
3414 alloc_large_system_hash("TCP established",
3415 sizeof(struct inet_ehash_bucket),
3416 thash_entries,
3417 (totalram_pages >= 128 * 1024) ?
3418 13 : 15,
3419 0,
3420 NULL,
3421 &tcp_hashinfo.ehash_mask,
3422 thash_entries ? 0 : 512 * 1024);
3423 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3424 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3425 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3426 }
3427 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3428 panic("TCP: failed to alloc ehash_locks");
3429 tcp_hashinfo.bhash =
3430 alloc_large_system_hash("TCP bind",
3431 sizeof(struct inet_bind_hashbucket),
3432 tcp_hashinfo.ehash_mask + 1,
3433 (totalram_pages >= 128 * 1024) ?
3434 13 : 15,
3435 0,
3436 &tcp_hashinfo.bhash_size,
3437 NULL,
3438 64 * 1024);
3439 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3440 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3441 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3442 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3443 }
3444
3445
3446 cnt = tcp_hashinfo.ehash_mask + 1;
3447
3448 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3449 sysctl_tcp_max_orphans = cnt / 2;
3450 sysctl_max_syn_backlog = max(128, cnt / 256);
3451
3452 tcp_init_mem(&init_net);
3453 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3454 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3455 max_share = min(4UL*1024*1024, limit);
3456
3457 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3458 sysctl_tcp_wmem[1] = 16*1024;
3459 sysctl_tcp_wmem[2] = max(64*1024, max_share);
3460
3461 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3462 sysctl_tcp_rmem[1] = 87380;
3463 sysctl_tcp_rmem[2] = max(87380, max_share);
3464
3465 pr_info("Hash tables configured (established %u bind %u)\n",
3466 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3467
3468 tcp_register_congestion_control(&tcp_reno);
3469
3470 memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3471 memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3472 tcp_secret_one.expires = jiffy; /* past due */
3473 tcp_secret_two.expires = jiffy; /* past due */
3474 tcp_secret_generating = &tcp_secret_one;
3475 tcp_secret_primary = &tcp_secret_one;
3476 tcp_secret_retiring = &tcp_secret_two;
3477 tcp_secret_secondary = &tcp_secret_two;
3478 }
kernel source for telekom puls (alcatel/mediatek)