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Merge remote-tracking branch 'asoc/fix/omap' into asoc-linus
[deliverable/linux.git] / net / ipv4 / tcp.c
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Mark Evans, <evansmp@uhura.aston.ac.uk>
11 * Corey Minyard <wf-rch!minyard@relay.EU.net>
12 * Florian La Roche, <flla@stud.uni-sb.de>
13 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
14 * Linus Torvalds, <torvalds@cs.helsinki.fi>
15 * Alan Cox, <gw4pts@gw4pts.ampr.org>
16 * Matthew Dillon, <dillon@apollo.west.oic.com>
17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
18 * Jorge Cwik, <jorge@laser.satlink.net>
19 *
20 * Fixes:
21 * Alan Cox : Numerous verify_area() calls
22 * Alan Cox : Set the ACK bit on a reset
23 * Alan Cox : Stopped it crashing if it closed while
24 * sk->inuse=1 and was trying to connect
25 * (tcp_err()).
26 * Alan Cox : All icmp error handling was broken
27 * pointers passed where wrong and the
28 * socket was looked up backwards. Nobody
29 * tested any icmp error code obviously.
30 * Alan Cox : tcp_err() now handled properly. It
31 * wakes people on errors. poll
32 * behaves and the icmp error race
33 * has gone by moving it into sock.c
34 * Alan Cox : tcp_send_reset() fixed to work for
35 * everything not just packets for
36 * unknown sockets.
37 * Alan Cox : tcp option processing.
38 * Alan Cox : Reset tweaked (still not 100%) [Had
39 * syn rule wrong]
40 * Herp Rosmanith : More reset fixes
41 * Alan Cox : No longer acks invalid rst frames.
42 * Acking any kind of RST is right out.
43 * Alan Cox : Sets an ignore me flag on an rst
44 * receive otherwise odd bits of prattle
45 * escape still
46 * Alan Cox : Fixed another acking RST frame bug.
47 * Should stop LAN workplace lockups.
48 * Alan Cox : Some tidyups using the new skb list
49 * facilities
50 * Alan Cox : sk->keepopen now seems to work
51 * Alan Cox : Pulls options out correctly on accepts
52 * Alan Cox : Fixed assorted sk->rqueue->next errors
53 * Alan Cox : PSH doesn't end a TCP read. Switched a
54 * bit to skb ops.
55 * Alan Cox : Tidied tcp_data to avoid a potential
56 * nasty.
57 * Alan Cox : Added some better commenting, as the
58 * tcp is hard to follow
59 * Alan Cox : Removed incorrect check for 20 * psh
60 * Michael O'Reilly : ack < copied bug fix.
61 * Johannes Stille : Misc tcp fixes (not all in yet).
62 * Alan Cox : FIN with no memory -> CRASH
63 * Alan Cox : Added socket option proto entries.
64 * Also added awareness of them to accept.
65 * Alan Cox : Added TCP options (SOL_TCP)
66 * Alan Cox : Switched wakeup calls to callbacks,
67 * so the kernel can layer network
68 * sockets.
69 * Alan Cox : Use ip_tos/ip_ttl settings.
70 * Alan Cox : Handle FIN (more) properly (we hope).
71 * Alan Cox : RST frames sent on unsynchronised
72 * state ack error.
73 * Alan Cox : Put in missing check for SYN bit.
74 * Alan Cox : Added tcp_select_window() aka NET2E
75 * window non shrink trick.
76 * Alan Cox : Added a couple of small NET2E timer
77 * fixes
78 * Charles Hedrick : TCP fixes
79 * Toomas Tamm : TCP window fixes
80 * Alan Cox : Small URG fix to rlogin ^C ack fight
81 * Charles Hedrick : Rewrote most of it to actually work
82 * Linus : Rewrote tcp_read() and URG handling
83 * completely
84 * Gerhard Koerting: Fixed some missing timer handling
85 * Matthew Dillon : Reworked TCP machine states as per RFC
86 * Gerhard Koerting: PC/TCP workarounds
87 * Adam Caldwell : Assorted timer/timing errors
88 * Matthew Dillon : Fixed another RST bug
89 * Alan Cox : Move to kernel side addressing changes.
90 * Alan Cox : Beginning work on TCP fastpathing
91 * (not yet usable)
92 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
93 * Alan Cox : TCP fast path debugging
94 * Alan Cox : Window clamping
95 * Michael Riepe : Bug in tcp_check()
96 * Matt Dillon : More TCP improvements and RST bug fixes
97 * Matt Dillon : Yet more small nasties remove from the
98 * TCP code (Be very nice to this man if
99 * tcp finally works 100%) 8)
100 * Alan Cox : BSD accept semantics.
101 * Alan Cox : Reset on closedown bug.
102 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
103 * Michael Pall : Handle poll() after URG properly in
104 * all cases.
105 * Michael Pall : Undo the last fix in tcp_read_urg()
106 * (multi URG PUSH broke rlogin).
107 * Michael Pall : Fix the multi URG PUSH problem in
108 * tcp_readable(), poll() after URG
109 * works now.
110 * Michael Pall : recv(...,MSG_OOB) never blocks in the
111 * BSD api.
112 * Alan Cox : Changed the semantics of sk->socket to
113 * fix a race and a signal problem with
114 * accept() and async I/O.
115 * Alan Cox : Relaxed the rules on tcp_sendto().
116 * Yury Shevchuk : Really fixed accept() blocking problem.
117 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
118 * clients/servers which listen in on
119 * fixed ports.
120 * Alan Cox : Cleaned the above up and shrank it to
121 * a sensible code size.
122 * Alan Cox : Self connect lockup fix.
123 * Alan Cox : No connect to multicast.
124 * Ross Biro : Close unaccepted children on master
125 * socket close.
126 * Alan Cox : Reset tracing code.
127 * Alan Cox : Spurious resets on shutdown.
128 * Alan Cox : Giant 15 minute/60 second timer error
129 * Alan Cox : Small whoops in polling before an
130 * accept.
131 * Alan Cox : Kept the state trace facility since
132 * it's handy for debugging.
133 * Alan Cox : More reset handler fixes.
134 * Alan Cox : Started rewriting the code based on
135 * the RFC's for other useful protocol
136 * references see: Comer, KA9Q NOS, and
137 * for a reference on the difference
138 * between specifications and how BSD
139 * works see the 4.4lite source.
140 * A.N.Kuznetsov : Don't time wait on completion of tidy
141 * close.
142 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
143 * Linus Torvalds : Fixed BSD port reuse to work first syn
144 * Alan Cox : Reimplemented timers as per the RFC
145 * and using multiple timers for sanity.
146 * Alan Cox : Small bug fixes, and a lot of new
147 * comments.
148 * Alan Cox : Fixed dual reader crash by locking
149 * the buffers (much like datagram.c)
150 * Alan Cox : Fixed stuck sockets in probe. A probe
151 * now gets fed up of retrying without
152 * (even a no space) answer.
153 * Alan Cox : Extracted closing code better
154 * Alan Cox : Fixed the closing state machine to
155 * resemble the RFC.
156 * Alan Cox : More 'per spec' fixes.
157 * Jorge Cwik : Even faster checksumming.
158 * Alan Cox : tcp_data() doesn't ack illegal PSH
159 * only frames. At least one pc tcp stack
160 * generates them.
161 * Alan Cox : Cache last socket.
162 * Alan Cox : Per route irtt.
163 * Matt Day : poll()->select() match BSD precisely on error
164 * Alan Cox : New buffers
165 * Marc Tamsky : Various sk->prot->retransmits and
166 * sk->retransmits misupdating fixed.
167 * Fixed tcp_write_timeout: stuck close,
168 * and TCP syn retries gets used now.
169 * Mark Yarvis : In tcp_read_wakeup(), don't send an
170 * ack if state is TCP_CLOSED.
171 * Alan Cox : Look up device on a retransmit - routes may
172 * change. Doesn't yet cope with MSS shrink right
173 * but it's a start!
174 * Marc Tamsky : Closing in closing fixes.
175 * Mike Shaver : RFC1122 verifications.
176 * Alan Cox : rcv_saddr errors.
177 * Alan Cox : Block double connect().
178 * Alan Cox : Small hooks for enSKIP.
179 * Alexey Kuznetsov: Path MTU discovery.
180 * Alan Cox : Support soft errors.
181 * Alan Cox : Fix MTU discovery pathological case
182 * when the remote claims no mtu!
183 * Marc Tamsky : TCP_CLOSE fix.
184 * Colin (G3TNE) : Send a reset on syn ack replies in
185 * window but wrong (fixes NT lpd problems)
186 * Pedro Roque : Better TCP window handling, delayed ack.
187 * Joerg Reuter : No modification of locked buffers in
188 * tcp_do_retransmit()
189 * Eric Schenk : Changed receiver side silly window
190 * avoidance algorithm to BSD style
191 * algorithm. This doubles throughput
192 * against machines running Solaris,
193 * and seems to result in general
194 * improvement.
195 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
196 * Willy Konynenberg : Transparent proxying support.
197 * Mike McLagan : Routing by source
198 * Keith Owens : Do proper merging with partial SKB's in
199 * tcp_do_sendmsg to avoid burstiness.
200 * Eric Schenk : Fix fast close down bug with
201 * shutdown() followed by close().
202 * Andi Kleen : Make poll agree with SIGIO
203 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
204 * lingertime == 0 (RFC 793 ABORT Call)
205 * Hirokazu Takahashi : Use copy_from_user() instead of
206 * csum_and_copy_from_user() if possible.
207 *
208 * This program is free software; you can redistribute it and/or
209 * modify it under the terms of the GNU General Public License
210 * as published by the Free Software Foundation; either version
211 * 2 of the License, or(at your option) any later version.
212 *
213 * Description of States:
214 *
215 * TCP_SYN_SENT sent a connection request, waiting for ack
216 *
217 * TCP_SYN_RECV received a connection request, sent ack,
218 * waiting for final ack in three-way handshake.
219 *
220 * TCP_ESTABLISHED connection established
221 *
222 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
223 * transmission of remaining buffered data
224 *
225 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
226 * to shutdown
227 *
228 * TCP_CLOSING both sides have shutdown but we still have
229 * data we have to finish sending
230 *
231 * TCP_TIME_WAIT timeout to catch resent junk before entering
232 * closed, can only be entered from FIN_WAIT2
233 * or CLOSING. Required because the other end
234 * may not have gotten our last ACK causing it
235 * to retransmit the data packet (which we ignore)
236 *
237 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
238 * us to finish writing our data and to shutdown
239 * (we have to close() to move on to LAST_ACK)
240 *
241 * TCP_LAST_ACK out side has shutdown after remote has
242 * shutdown. There may still be data in our
243 * buffer that we have to finish sending
244 *
245 * TCP_CLOSE socket is finished
246 */
247
248 #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/inet_common.h>
274 #include <net/tcp.h>
275 #include <net/xfrm.h>
276 #include <net/ip.h>
277 #include <net/sock.h>
278
279 #include <asm/uaccess.h>
280 #include <asm/ioctls.h>
281 #include <net/busy_poll.h>
282
283 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
284
285 int sysctl_tcp_min_tso_segs __read_mostly = 2;
286
287 int sysctl_tcp_autocorking __read_mostly = 1;
288
289 struct percpu_counter tcp_orphan_count;
290 EXPORT_SYMBOL_GPL(tcp_orphan_count);
291
292 long sysctl_tcp_mem[3] __read_mostly;
293 int sysctl_tcp_wmem[3] __read_mostly;
294 int sysctl_tcp_rmem[3] __read_mostly;
295
296 EXPORT_SYMBOL(sysctl_tcp_mem);
297 EXPORT_SYMBOL(sysctl_tcp_rmem);
298 EXPORT_SYMBOL(sysctl_tcp_wmem);
299
300 atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
301 EXPORT_SYMBOL(tcp_memory_allocated);
302
303 /*
304 * Current number of TCP sockets.
305 */
306 struct percpu_counter tcp_sockets_allocated;
307 EXPORT_SYMBOL(tcp_sockets_allocated);
308
309 /*
310 * TCP splice context
311 */
312 struct tcp_splice_state {
313 struct pipe_inode_info *pipe;
314 size_t len;
315 unsigned int flags;
316 };
317
318 /*
319 * Pressure flag: try to collapse.
320 * Technical note: it is used by multiple contexts non atomically.
321 * All the __sk_mem_schedule() is of this nature: accounting
322 * is strict, actions are advisory and have some latency.
323 */
324 int tcp_memory_pressure __read_mostly;
325 EXPORT_SYMBOL(tcp_memory_pressure);
326
327 void tcp_enter_memory_pressure(struct sock *sk)
328 {
329 if (!tcp_memory_pressure) {
330 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
331 tcp_memory_pressure = 1;
332 }
333 }
334 EXPORT_SYMBOL(tcp_enter_memory_pressure);
335
336 /* Convert seconds to retransmits based on initial and max timeout */
337 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
338 {
339 u8 res = 0;
340
341 if (seconds > 0) {
342 int period = timeout;
343
344 res = 1;
345 while (seconds > period && res < 255) {
346 res++;
347 timeout <<= 1;
348 if (timeout > rto_max)
349 timeout = rto_max;
350 period += timeout;
351 }
352 }
353 return res;
354 }
355
356 /* Convert retransmits to seconds based on initial and max timeout */
357 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
358 {
359 int period = 0;
360
361 if (retrans > 0) {
362 period = timeout;
363 while (--retrans) {
364 timeout <<= 1;
365 if (timeout > rto_max)
366 timeout = rto_max;
367 period += timeout;
368 }
369 }
370 return period;
371 }
372
373 /* Address-family independent initialization for a tcp_sock.
374 *
375 * NOTE: A lot of things set to zero explicitly by call to
376 * sk_alloc() so need not be done here.
377 */
378 void tcp_init_sock(struct sock *sk)
379 {
380 struct inet_connection_sock *icsk = inet_csk(sk);
381 struct tcp_sock *tp = tcp_sk(sk);
382
383 __skb_queue_head_init(&tp->out_of_order_queue);
384 tcp_init_xmit_timers(sk);
385 tcp_prequeue_init(tp);
386 INIT_LIST_HEAD(&tp->tsq_node);
387
388 icsk->icsk_rto = TCP_TIMEOUT_INIT;
389 tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
390
391 /* So many TCP implementations out there (incorrectly) count the
392 * initial SYN frame in their delayed-ACK and congestion control
393 * algorithms that we must have the following bandaid to talk
394 * efficiently to them. -DaveM
395 */
396 tp->snd_cwnd = TCP_INIT_CWND;
397
398 /* See draft-stevens-tcpca-spec-01 for discussion of the
399 * initialization of these values.
400 */
401 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
402 tp->snd_cwnd_clamp = ~0;
403 tp->mss_cache = TCP_MSS_DEFAULT;
404
405 tp->reordering = sysctl_tcp_reordering;
406 tcp_enable_early_retrans(tp);
407 tcp_assign_congestion_control(sk);
408
409 tp->tsoffset = 0;
410
411 sk->sk_state = TCP_CLOSE;
412
413 sk->sk_write_space = sk_stream_write_space;
414 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
415
416 icsk->icsk_sync_mss = tcp_sync_mss;
417
418 sk->sk_sndbuf = sysctl_tcp_wmem[1];
419 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
420
421 local_bh_disable();
422 sock_update_memcg(sk);
423 sk_sockets_allocated_inc(sk);
424 local_bh_enable();
425 }
426 EXPORT_SYMBOL(tcp_init_sock);
427
428 static void tcp_tx_timestamp(struct sock *sk, struct sk_buff *skb)
429 {
430 if (sk->sk_tsflags) {
431 struct skb_shared_info *shinfo = skb_shinfo(skb);
432
433 sock_tx_timestamp(sk, &shinfo->tx_flags);
434 if (shinfo->tx_flags & SKBTX_ANY_TSTAMP)
435 shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
436 }
437 }
438
439 /*
440 * Wait for a TCP event.
441 *
442 * Note that we don't need to lock the socket, as the upper poll layers
443 * take care of normal races (between the test and the event) and we don't
444 * go look at any of the socket buffers directly.
445 */
446 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
447 {
448 unsigned int mask;
449 struct sock *sk = sock->sk;
450 const struct tcp_sock *tp = tcp_sk(sk);
451
452 sock_rps_record_flow(sk);
453
454 sock_poll_wait(file, sk_sleep(sk), wait);
455 if (sk->sk_state == TCP_LISTEN)
456 return inet_csk_listen_poll(sk);
457
458 /* Socket is not locked. We are protected from async events
459 * by poll logic and correct handling of state changes
460 * made by other threads is impossible in any case.
461 */
462
463 mask = 0;
464
465 /*
466 * POLLHUP is certainly not done right. But poll() doesn't
467 * have a notion of HUP in just one direction, and for a
468 * socket the read side is more interesting.
469 *
470 * Some poll() documentation says that POLLHUP is incompatible
471 * with the POLLOUT/POLLWR flags, so somebody should check this
472 * all. But careful, it tends to be safer to return too many
473 * bits than too few, and you can easily break real applications
474 * if you don't tell them that something has hung up!
475 *
476 * Check-me.
477 *
478 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
479 * our fs/select.c). It means that after we received EOF,
480 * poll always returns immediately, making impossible poll() on write()
481 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
482 * if and only if shutdown has been made in both directions.
483 * Actually, it is interesting to look how Solaris and DUX
484 * solve this dilemma. I would prefer, if POLLHUP were maskable,
485 * then we could set it on SND_SHUTDOWN. BTW examples given
486 * in Stevens' books assume exactly this behaviour, it explains
487 * why POLLHUP is incompatible with POLLOUT. --ANK
488 *
489 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
490 * blocking on fresh not-connected or disconnected socket. --ANK
491 */
492 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
493 mask |= POLLHUP;
494 if (sk->sk_shutdown & RCV_SHUTDOWN)
495 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
496
497 /* Connected or passive Fast Open socket? */
498 if (sk->sk_state != TCP_SYN_SENT &&
499 (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk != NULL)) {
500 int target = sock_rcvlowat(sk, 0, INT_MAX);
501
502 if (tp->urg_seq == tp->copied_seq &&
503 !sock_flag(sk, SOCK_URGINLINE) &&
504 tp->urg_data)
505 target++;
506
507 /* Potential race condition. If read of tp below will
508 * escape above sk->sk_state, we can be illegally awaken
509 * in SYN_* states. */
510 if (tp->rcv_nxt - tp->copied_seq >= target)
511 mask |= POLLIN | POLLRDNORM;
512
513 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
514 if (sk_stream_is_writeable(sk)) {
515 mask |= POLLOUT | POLLWRNORM;
516 } else { /* send SIGIO later */
517 set_bit(SOCK_ASYNC_NOSPACE,
518 &sk->sk_socket->flags);
519 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
520
521 /* Race breaker. If space is freed after
522 * wspace test but before the flags are set,
523 * IO signal will be lost.
524 */
525 if (sk_stream_is_writeable(sk))
526 mask |= POLLOUT | POLLWRNORM;
527 }
528 } else
529 mask |= POLLOUT | POLLWRNORM;
530
531 if (tp->urg_data & TCP_URG_VALID)
532 mask |= POLLPRI;
533 }
534 /* This barrier is coupled with smp_wmb() in tcp_reset() */
535 smp_rmb();
536 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
537 mask |= POLLERR;
538
539 return mask;
540 }
541 EXPORT_SYMBOL(tcp_poll);
542
543 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
544 {
545 struct tcp_sock *tp = tcp_sk(sk);
546 int answ;
547 bool slow;
548
549 switch (cmd) {
550 case SIOCINQ:
551 if (sk->sk_state == TCP_LISTEN)
552 return -EINVAL;
553
554 slow = lock_sock_fast(sk);
555 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
556 answ = 0;
557 else if (sock_flag(sk, SOCK_URGINLINE) ||
558 !tp->urg_data ||
559 before(tp->urg_seq, tp->copied_seq) ||
560 !before(tp->urg_seq, tp->rcv_nxt)) {
561
562 answ = tp->rcv_nxt - tp->copied_seq;
563
564 /* Subtract 1, if FIN was received */
565 if (answ && sock_flag(sk, SOCK_DONE))
566 answ--;
567 } else
568 answ = tp->urg_seq - tp->copied_seq;
569 unlock_sock_fast(sk, slow);
570 break;
571 case SIOCATMARK:
572 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
573 break;
574 case SIOCOUTQ:
575 if (sk->sk_state == TCP_LISTEN)
576 return -EINVAL;
577
578 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
579 answ = 0;
580 else
581 answ = tp->write_seq - tp->snd_una;
582 break;
583 case SIOCOUTQNSD:
584 if (sk->sk_state == TCP_LISTEN)
585 return -EINVAL;
586
587 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
588 answ = 0;
589 else
590 answ = tp->write_seq - tp->snd_nxt;
591 break;
592 default:
593 return -ENOIOCTLCMD;
594 }
595
596 return put_user(answ, (int __user *)arg);
597 }
598 EXPORT_SYMBOL(tcp_ioctl);
599
600 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
601 {
602 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
603 tp->pushed_seq = tp->write_seq;
604 }
605
606 static inline bool forced_push(const struct tcp_sock *tp)
607 {
608 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
609 }
610
611 static void skb_entail(struct sock *sk, struct sk_buff *skb)
612 {
613 struct tcp_sock *tp = tcp_sk(sk);
614 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
615
616 skb->csum = 0;
617 tcb->seq = tcb->end_seq = tp->write_seq;
618 tcb->tcp_flags = TCPHDR_ACK;
619 tcb->sacked = 0;
620 __skb_header_release(skb);
621 tcp_add_write_queue_tail(sk, skb);
622 sk->sk_wmem_queued += skb->truesize;
623 sk_mem_charge(sk, skb->truesize);
624 if (tp->nonagle & TCP_NAGLE_PUSH)
625 tp->nonagle &= ~TCP_NAGLE_PUSH;
626 }
627
628 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
629 {
630 if (flags & MSG_OOB)
631 tp->snd_up = tp->write_seq;
632 }
633
634 /* If a not yet filled skb is pushed, do not send it if
635 * we have data packets in Qdisc or NIC queues :
636 * Because TX completion will happen shortly, it gives a chance
637 * to coalesce future sendmsg() payload into this skb, without
638 * need for a timer, and with no latency trade off.
639 * As packets containing data payload have a bigger truesize
640 * than pure acks (dataless) packets, the last checks prevent
641 * autocorking if we only have an ACK in Qdisc/NIC queues,
642 * or if TX completion was delayed after we processed ACK packet.
643 */
644 static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
645 int size_goal)
646 {
647 return skb->len < size_goal &&
648 sysctl_tcp_autocorking &&
649 skb != tcp_write_queue_head(sk) &&
650 atomic_read(&sk->sk_wmem_alloc) > skb->truesize;
651 }
652
653 static void tcp_push(struct sock *sk, int flags, int mss_now,
654 int nonagle, int size_goal)
655 {
656 struct tcp_sock *tp = tcp_sk(sk);
657 struct sk_buff *skb;
658
659 if (!tcp_send_head(sk))
660 return;
661
662 skb = tcp_write_queue_tail(sk);
663 if (!(flags & MSG_MORE) || forced_push(tp))
664 tcp_mark_push(tp, skb);
665
666 tcp_mark_urg(tp, flags);
667
668 if (tcp_should_autocork(sk, skb, size_goal)) {
669
670 /* avoid atomic op if TSQ_THROTTLED bit is already set */
671 if (!test_bit(TSQ_THROTTLED, &tp->tsq_flags)) {
672 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
673 set_bit(TSQ_THROTTLED, &tp->tsq_flags);
674 }
675 /* It is possible TX completion already happened
676 * before we set TSQ_THROTTLED.
677 */
678 if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize)
679 return;
680 }
681
682 if (flags & MSG_MORE)
683 nonagle = TCP_NAGLE_CORK;
684
685 __tcp_push_pending_frames(sk, mss_now, nonagle);
686 }
687
688 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
689 unsigned int offset, size_t len)
690 {
691 struct tcp_splice_state *tss = rd_desc->arg.data;
692 int ret;
693
694 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
695 tss->flags);
696 if (ret > 0)
697 rd_desc->count -= ret;
698 return ret;
699 }
700
701 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
702 {
703 /* Store TCP splice context information in read_descriptor_t. */
704 read_descriptor_t rd_desc = {
705 .arg.data = tss,
706 .count = tss->len,
707 };
708
709 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
710 }
711
712 /**
713 * tcp_splice_read - splice data from TCP socket to a pipe
714 * @sock: socket to splice from
715 * @ppos: position (not valid)
716 * @pipe: pipe to splice to
717 * @len: number of bytes to splice
718 * @flags: splice modifier flags
719 *
720 * Description:
721 * Will read pages from given socket and fill them into a pipe.
722 *
723 **/
724 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
725 struct pipe_inode_info *pipe, size_t len,
726 unsigned int flags)
727 {
728 struct sock *sk = sock->sk;
729 struct tcp_splice_state tss = {
730 .pipe = pipe,
731 .len = len,
732 .flags = flags,
733 };
734 long timeo;
735 ssize_t spliced;
736 int ret;
737
738 sock_rps_record_flow(sk);
739 /*
740 * We can't seek on a socket input
741 */
742 if (unlikely(*ppos))
743 return -ESPIPE;
744
745 ret = spliced = 0;
746
747 lock_sock(sk);
748
749 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
750 while (tss.len) {
751 ret = __tcp_splice_read(sk, &tss);
752 if (ret < 0)
753 break;
754 else if (!ret) {
755 if (spliced)
756 break;
757 if (sock_flag(sk, SOCK_DONE))
758 break;
759 if (sk->sk_err) {
760 ret = sock_error(sk);
761 break;
762 }
763 if (sk->sk_shutdown & RCV_SHUTDOWN)
764 break;
765 if (sk->sk_state == TCP_CLOSE) {
766 /*
767 * This occurs when user tries to read
768 * from never connected socket.
769 */
770 if (!sock_flag(sk, SOCK_DONE))
771 ret = -ENOTCONN;
772 break;
773 }
774 if (!timeo) {
775 ret = -EAGAIN;
776 break;
777 }
778 sk_wait_data(sk, &timeo);
779 if (signal_pending(current)) {
780 ret = sock_intr_errno(timeo);
781 break;
782 }
783 continue;
784 }
785 tss.len -= ret;
786 spliced += ret;
787
788 if (!timeo)
789 break;
790 release_sock(sk);
791 lock_sock(sk);
792
793 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
794 (sk->sk_shutdown & RCV_SHUTDOWN) ||
795 signal_pending(current))
796 break;
797 }
798
799 release_sock(sk);
800
801 if (spliced)
802 return spliced;
803
804 return ret;
805 }
806 EXPORT_SYMBOL(tcp_splice_read);
807
808 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
809 {
810 struct sk_buff *skb;
811
812 /* The TCP header must be at least 32-bit aligned. */
813 size = ALIGN(size, 4);
814
815 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
816 if (skb) {
817 if (sk_wmem_schedule(sk, skb->truesize)) {
818 skb_reserve(skb, sk->sk_prot->max_header);
819 /*
820 * Make sure that we have exactly size bytes
821 * available to the caller, no more, no less.
822 */
823 skb->reserved_tailroom = skb->end - skb->tail - size;
824 return skb;
825 }
826 __kfree_skb(skb);
827 } else {
828 sk->sk_prot->enter_memory_pressure(sk);
829 sk_stream_moderate_sndbuf(sk);
830 }
831 return NULL;
832 }
833
834 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
835 int large_allowed)
836 {
837 struct tcp_sock *tp = tcp_sk(sk);
838 u32 new_size_goal, size_goal, hlen;
839
840 if (!large_allowed || !sk_can_gso(sk))
841 return mss_now;
842
843 /* Maybe we should/could use sk->sk_prot->max_header here ? */
844 hlen = inet_csk(sk)->icsk_af_ops->net_header_len +
845 inet_csk(sk)->icsk_ext_hdr_len +
846 tp->tcp_header_len;
847
848 new_size_goal = sk->sk_gso_max_size - 1 - hlen;
849 new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);
850
851 /* We try hard to avoid divides here */
852 size_goal = tp->gso_segs * mss_now;
853 if (unlikely(new_size_goal < size_goal ||
854 new_size_goal >= size_goal + mss_now)) {
855 tp->gso_segs = min_t(u16, new_size_goal / mss_now,
856 sk->sk_gso_max_segs);
857 size_goal = tp->gso_segs * mss_now;
858 }
859
860 return max(size_goal, mss_now);
861 }
862
863 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
864 {
865 int mss_now;
866
867 mss_now = tcp_current_mss(sk);
868 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
869
870 return mss_now;
871 }
872
873 static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
874 size_t size, int flags)
875 {
876 struct tcp_sock *tp = tcp_sk(sk);
877 int mss_now, size_goal;
878 int err;
879 ssize_t copied;
880 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
881
882 /* Wait for a connection to finish. One exception is TCP Fast Open
883 * (passive side) where data is allowed to be sent before a connection
884 * is fully established.
885 */
886 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
887 !tcp_passive_fastopen(sk)) {
888 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
889 goto out_err;
890 }
891
892 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
893
894 mss_now = tcp_send_mss(sk, &size_goal, flags);
895 copied = 0;
896
897 err = -EPIPE;
898 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
899 goto out_err;
900
901 while (size > 0) {
902 struct sk_buff *skb = tcp_write_queue_tail(sk);
903 int copy, i;
904 bool can_coalesce;
905
906 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
907 new_segment:
908 if (!sk_stream_memory_free(sk))
909 goto wait_for_sndbuf;
910
911 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
912 if (!skb)
913 goto wait_for_memory;
914
915 skb_entail(sk, skb);
916 copy = size_goal;
917 }
918
919 if (copy > size)
920 copy = size;
921
922 i = skb_shinfo(skb)->nr_frags;
923 can_coalesce = skb_can_coalesce(skb, i, page, offset);
924 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
925 tcp_mark_push(tp, skb);
926 goto new_segment;
927 }
928 if (!sk_wmem_schedule(sk, copy))
929 goto wait_for_memory;
930
931 if (can_coalesce) {
932 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
933 } else {
934 get_page(page);
935 skb_fill_page_desc(skb, i, page, offset, copy);
936 }
937 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
938
939 skb->len += copy;
940 skb->data_len += copy;
941 skb->truesize += copy;
942 sk->sk_wmem_queued += copy;
943 sk_mem_charge(sk, copy);
944 skb->ip_summed = CHECKSUM_PARTIAL;
945 tp->write_seq += copy;
946 TCP_SKB_CB(skb)->end_seq += copy;
947 tcp_skb_pcount_set(skb, 0);
948
949 if (!copied)
950 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
951
952 copied += copy;
953 offset += copy;
954 if (!(size -= copy)) {
955 tcp_tx_timestamp(sk, skb);
956 goto out;
957 }
958
959 if (skb->len < size_goal || (flags & MSG_OOB))
960 continue;
961
962 if (forced_push(tp)) {
963 tcp_mark_push(tp, skb);
964 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
965 } else if (skb == tcp_send_head(sk))
966 tcp_push_one(sk, mss_now);
967 continue;
968
969 wait_for_sndbuf:
970 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
971 wait_for_memory:
972 tcp_push(sk, flags & ~MSG_MORE, mss_now,
973 TCP_NAGLE_PUSH, size_goal);
974
975 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
976 goto do_error;
977
978 mss_now = tcp_send_mss(sk, &size_goal, flags);
979 }
980
981 out:
982 if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
983 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
984 return copied;
985
986 do_error:
987 if (copied)
988 goto out;
989 out_err:
990 return sk_stream_error(sk, flags, err);
991 }
992
993 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
994 size_t size, int flags)
995 {
996 ssize_t res;
997
998 if (!(sk->sk_route_caps & NETIF_F_SG) ||
999 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
1000 return sock_no_sendpage(sk->sk_socket, page, offset, size,
1001 flags);
1002
1003 lock_sock(sk);
1004 res = do_tcp_sendpages(sk, page, offset, size, flags);
1005 release_sock(sk);
1006 return res;
1007 }
1008 EXPORT_SYMBOL(tcp_sendpage);
1009
1010 static inline int select_size(const struct sock *sk, bool sg)
1011 {
1012 const struct tcp_sock *tp = tcp_sk(sk);
1013 int tmp = tp->mss_cache;
1014
1015 if (sg) {
1016 if (sk_can_gso(sk)) {
1017 /* Small frames wont use a full page:
1018 * Payload will immediately follow tcp header.
1019 */
1020 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
1021 } else {
1022 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
1023
1024 if (tmp >= pgbreak &&
1025 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
1026 tmp = pgbreak;
1027 }
1028 }
1029
1030 return tmp;
1031 }
1032
1033 void tcp_free_fastopen_req(struct tcp_sock *tp)
1034 {
1035 if (tp->fastopen_req != NULL) {
1036 kfree(tp->fastopen_req);
1037 tp->fastopen_req = NULL;
1038 }
1039 }
1040
1041 static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1042 int *copied, size_t size)
1043 {
1044 struct tcp_sock *tp = tcp_sk(sk);
1045 int err, flags;
1046
1047 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
1048 return -EOPNOTSUPP;
1049 if (tp->fastopen_req != NULL)
1050 return -EALREADY; /* Another Fast Open is in progress */
1051
1052 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1053 sk->sk_allocation);
1054 if (unlikely(tp->fastopen_req == NULL))
1055 return -ENOBUFS;
1056 tp->fastopen_req->data = msg;
1057 tp->fastopen_req->size = size;
1058
1059 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1060 err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1061 msg->msg_namelen, flags);
1062 *copied = tp->fastopen_req->copied;
1063 tcp_free_fastopen_req(tp);
1064 return err;
1065 }
1066
1067 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1068 size_t size)
1069 {
1070 struct tcp_sock *tp = tcp_sk(sk);
1071 struct sk_buff *skb;
1072 int flags, err, copied = 0;
1073 int mss_now = 0, size_goal, copied_syn = 0;
1074 bool sg;
1075 long timeo;
1076
1077 lock_sock(sk);
1078
1079 flags = msg->msg_flags;
1080 if (flags & MSG_FASTOPEN) {
1081 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1082 if (err == -EINPROGRESS && copied_syn > 0)
1083 goto out;
1084 else if (err)
1085 goto out_err;
1086 }
1087
1088 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1089
1090 /* Wait for a connection to finish. One exception is TCP Fast Open
1091 * (passive side) where data is allowed to be sent before a connection
1092 * is fully established.
1093 */
1094 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1095 !tcp_passive_fastopen(sk)) {
1096 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1097 goto do_error;
1098 }
1099
1100 if (unlikely(tp->repair)) {
1101 if (tp->repair_queue == TCP_RECV_QUEUE) {
1102 copied = tcp_send_rcvq(sk, msg, size);
1103 goto out_nopush;
1104 }
1105
1106 err = -EINVAL;
1107 if (tp->repair_queue == TCP_NO_QUEUE)
1108 goto out_err;
1109
1110 /* 'common' sending to sendq */
1111 }
1112
1113 /* This should be in poll */
1114 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1115
1116 mss_now = tcp_send_mss(sk, &size_goal, flags);
1117
1118 /* Ok commence sending. */
1119 copied = 0;
1120
1121 err = -EPIPE;
1122 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1123 goto out_err;
1124
1125 sg = !!(sk->sk_route_caps & NETIF_F_SG);
1126
1127 while (iov_iter_count(&msg->msg_iter)) {
1128 int copy = 0;
1129 int max = size_goal;
1130
1131 skb = tcp_write_queue_tail(sk);
1132 if (tcp_send_head(sk)) {
1133 if (skb->ip_summed == CHECKSUM_NONE)
1134 max = mss_now;
1135 copy = max - skb->len;
1136 }
1137
1138 if (copy <= 0) {
1139 new_segment:
1140 /* Allocate new segment. If the interface is SG,
1141 * allocate skb fitting to single page.
1142 */
1143 if (!sk_stream_memory_free(sk))
1144 goto wait_for_sndbuf;
1145
1146 skb = sk_stream_alloc_skb(sk,
1147 select_size(sk, sg),
1148 sk->sk_allocation);
1149 if (!skb)
1150 goto wait_for_memory;
1151
1152 /*
1153 * Check whether we can use HW checksum.
1154 */
1155 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1156 skb->ip_summed = CHECKSUM_PARTIAL;
1157
1158 skb_entail(sk, skb);
1159 copy = size_goal;
1160 max = size_goal;
1161
1162 /* All packets are restored as if they have
1163 * already been sent. skb_mstamp isn't set to
1164 * avoid wrong rtt estimation.
1165 */
1166 if (tp->repair)
1167 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
1168 }
1169
1170 /* Try to append data to the end of skb. */
1171 if (copy > iov_iter_count(&msg->msg_iter))
1172 copy = iov_iter_count(&msg->msg_iter);
1173
1174 /* Where to copy to? */
1175 if (skb_availroom(skb) > 0) {
1176 /* We have some space in skb head. Superb! */
1177 copy = min_t(int, copy, skb_availroom(skb));
1178 err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);
1179 if (err)
1180 goto do_fault;
1181 } else {
1182 bool merge = true;
1183 int i = skb_shinfo(skb)->nr_frags;
1184 struct page_frag *pfrag = sk_page_frag(sk);
1185
1186 if (!sk_page_frag_refill(sk, pfrag))
1187 goto wait_for_memory;
1188
1189 if (!skb_can_coalesce(skb, i, pfrag->page,
1190 pfrag->offset)) {
1191 if (i == MAX_SKB_FRAGS || !sg) {
1192 tcp_mark_push(tp, skb);
1193 goto new_segment;
1194 }
1195 merge = false;
1196 }
1197
1198 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1199
1200 if (!sk_wmem_schedule(sk, copy))
1201 goto wait_for_memory;
1202
1203 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
1204 pfrag->page,
1205 pfrag->offset,
1206 copy);
1207 if (err)
1208 goto do_error;
1209
1210 /* Update the skb. */
1211 if (merge) {
1212 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1213 } else {
1214 skb_fill_page_desc(skb, i, pfrag->page,
1215 pfrag->offset, copy);
1216 get_page(pfrag->page);
1217 }
1218 pfrag->offset += copy;
1219 }
1220
1221 if (!copied)
1222 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1223
1224 tp->write_seq += copy;
1225 TCP_SKB_CB(skb)->end_seq += copy;
1226 tcp_skb_pcount_set(skb, 0);
1227
1228 copied += copy;
1229 if (!iov_iter_count(&msg->msg_iter)) {
1230 tcp_tx_timestamp(sk, skb);
1231 goto out;
1232 }
1233
1234 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1235 continue;
1236
1237 if (forced_push(tp)) {
1238 tcp_mark_push(tp, skb);
1239 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1240 } else if (skb == tcp_send_head(sk))
1241 tcp_push_one(sk, mss_now);
1242 continue;
1243
1244 wait_for_sndbuf:
1245 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1246 wait_for_memory:
1247 if (copied)
1248 tcp_push(sk, flags & ~MSG_MORE, mss_now,
1249 TCP_NAGLE_PUSH, size_goal);
1250
1251 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1252 goto do_error;
1253
1254 mss_now = tcp_send_mss(sk, &size_goal, flags);
1255 }
1256
1257 out:
1258 if (copied)
1259 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1260 out_nopush:
1261 release_sock(sk);
1262 return copied + copied_syn;
1263
1264 do_fault:
1265 if (!skb->len) {
1266 tcp_unlink_write_queue(skb, sk);
1267 /* It is the one place in all of TCP, except connection
1268 * reset, where we can be unlinking the send_head.
1269 */
1270 tcp_check_send_head(sk, skb);
1271 sk_wmem_free_skb(sk, skb);
1272 }
1273
1274 do_error:
1275 if (copied + copied_syn)
1276 goto out;
1277 out_err:
1278 err = sk_stream_error(sk, flags, err);
1279 release_sock(sk);
1280 return err;
1281 }
1282 EXPORT_SYMBOL(tcp_sendmsg);
1283
1284 /*
1285 * Handle reading urgent data. BSD has very simple semantics for
1286 * this, no blocking and very strange errors 8)
1287 */
1288
1289 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1290 {
1291 struct tcp_sock *tp = tcp_sk(sk);
1292
1293 /* No URG data to read. */
1294 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1295 tp->urg_data == TCP_URG_READ)
1296 return -EINVAL; /* Yes this is right ! */
1297
1298 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1299 return -ENOTCONN;
1300
1301 if (tp->urg_data & TCP_URG_VALID) {
1302 int err = 0;
1303 char c = tp->urg_data;
1304
1305 if (!(flags & MSG_PEEK))
1306 tp->urg_data = TCP_URG_READ;
1307
1308 /* Read urgent data. */
1309 msg->msg_flags |= MSG_OOB;
1310
1311 if (len > 0) {
1312 if (!(flags & MSG_TRUNC))
1313 err = memcpy_to_msg(msg, &c, 1);
1314 len = 1;
1315 } else
1316 msg->msg_flags |= MSG_TRUNC;
1317
1318 return err ? -EFAULT : len;
1319 }
1320
1321 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1322 return 0;
1323
1324 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1325 * the available implementations agree in this case:
1326 * this call should never block, independent of the
1327 * blocking state of the socket.
1328 * Mike <pall@rz.uni-karlsruhe.de>
1329 */
1330 return -EAGAIN;
1331 }
1332
1333 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1334 {
1335 struct sk_buff *skb;
1336 int copied = 0, err = 0;
1337
1338 /* XXX -- need to support SO_PEEK_OFF */
1339
1340 skb_queue_walk(&sk->sk_write_queue, skb) {
1341 err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
1342 if (err)
1343 break;
1344
1345 copied += skb->len;
1346 }
1347
1348 return err ?: copied;
1349 }
1350
1351 /* Clean up the receive buffer for full frames taken by the user,
1352 * then send an ACK if necessary. COPIED is the number of bytes
1353 * tcp_recvmsg has given to the user so far, it speeds up the
1354 * calculation of whether or not we must ACK for the sake of
1355 * a window update.
1356 */
1357 static void tcp_cleanup_rbuf(struct sock *sk, int copied)
1358 {
1359 struct tcp_sock *tp = tcp_sk(sk);
1360 bool time_to_ack = false;
1361
1362 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1363
1364 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1365 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1366 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1367
1368 if (inet_csk_ack_scheduled(sk)) {
1369 const struct inet_connection_sock *icsk = inet_csk(sk);
1370 /* Delayed ACKs frequently hit locked sockets during bulk
1371 * receive. */
1372 if (icsk->icsk_ack.blocked ||
1373 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1374 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1375 /*
1376 * If this read emptied read buffer, we send ACK, if
1377 * connection is not bidirectional, user drained
1378 * receive buffer and there was a small segment
1379 * in queue.
1380 */
1381 (copied > 0 &&
1382 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1383 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1384 !icsk->icsk_ack.pingpong)) &&
1385 !atomic_read(&sk->sk_rmem_alloc)))
1386 time_to_ack = true;
1387 }
1388
1389 /* We send an ACK if we can now advertise a non-zero window
1390 * which has been raised "significantly".
1391 *
1392 * Even if window raised up to infinity, do not send window open ACK
1393 * in states, where we will not receive more. It is useless.
1394 */
1395 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1396 __u32 rcv_window_now = tcp_receive_window(tp);
1397
1398 /* Optimize, __tcp_select_window() is not cheap. */
1399 if (2*rcv_window_now <= tp->window_clamp) {
1400 __u32 new_window = __tcp_select_window(sk);
1401
1402 /* Send ACK now, if this read freed lots of space
1403 * in our buffer. Certainly, new_window is new window.
1404 * We can advertise it now, if it is not less than current one.
1405 * "Lots" means "at least twice" here.
1406 */
1407 if (new_window && new_window >= 2 * rcv_window_now)
1408 time_to_ack = true;
1409 }
1410 }
1411 if (time_to_ack)
1412 tcp_send_ack(sk);
1413 }
1414
1415 static void tcp_prequeue_process(struct sock *sk)
1416 {
1417 struct sk_buff *skb;
1418 struct tcp_sock *tp = tcp_sk(sk);
1419
1420 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1421
1422 /* RX process wants to run with disabled BHs, though it is not
1423 * necessary */
1424 local_bh_disable();
1425 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1426 sk_backlog_rcv(sk, skb);
1427 local_bh_enable();
1428
1429 /* Clear memory counter. */
1430 tp->ucopy.memory = 0;
1431 }
1432
1433 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1434 {
1435 struct sk_buff *skb;
1436 u32 offset;
1437
1438 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1439 offset = seq - TCP_SKB_CB(skb)->seq;
1440 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
1441 offset--;
1442 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
1443 *off = offset;
1444 return skb;
1445 }
1446 /* This looks weird, but this can happen if TCP collapsing
1447 * splitted a fat GRO packet, while we released socket lock
1448 * in skb_splice_bits()
1449 */
1450 sk_eat_skb(sk, skb);
1451 }
1452 return NULL;
1453 }
1454
1455 /*
1456 * This routine provides an alternative to tcp_recvmsg() for routines
1457 * that would like to handle copying from skbuffs directly in 'sendfile'
1458 * fashion.
1459 * Note:
1460 * - It is assumed that the socket was locked by the caller.
1461 * - The routine does not block.
1462 * - At present, there is no support for reading OOB data
1463 * or for 'peeking' the socket using this routine
1464 * (although both would be easy to implement).
1465 */
1466 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1467 sk_read_actor_t recv_actor)
1468 {
1469 struct sk_buff *skb;
1470 struct tcp_sock *tp = tcp_sk(sk);
1471 u32 seq = tp->copied_seq;
1472 u32 offset;
1473 int copied = 0;
1474
1475 if (sk->sk_state == TCP_LISTEN)
1476 return -ENOTCONN;
1477 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1478 if (offset < skb->len) {
1479 int used;
1480 size_t len;
1481
1482 len = skb->len - offset;
1483 /* Stop reading if we hit a patch of urgent data */
1484 if (tp->urg_data) {
1485 u32 urg_offset = tp->urg_seq - seq;
1486 if (urg_offset < len)
1487 len = urg_offset;
1488 if (!len)
1489 break;
1490 }
1491 used = recv_actor(desc, skb, offset, len);
1492 if (used <= 0) {
1493 if (!copied)
1494 copied = used;
1495 break;
1496 } else if (used <= len) {
1497 seq += used;
1498 copied += used;
1499 offset += used;
1500 }
1501 /* If recv_actor drops the lock (e.g. TCP splice
1502 * receive) the skb pointer might be invalid when
1503 * getting here: tcp_collapse might have deleted it
1504 * while aggregating skbs from the socket queue.
1505 */
1506 skb = tcp_recv_skb(sk, seq - 1, &offset);
1507 if (!skb)
1508 break;
1509 /* TCP coalescing might have appended data to the skb.
1510 * Try to splice more frags
1511 */
1512 if (offset + 1 != skb->len)
1513 continue;
1514 }
1515 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1516 sk_eat_skb(sk, skb);
1517 ++seq;
1518 break;
1519 }
1520 sk_eat_skb(sk, skb);
1521 if (!desc->count)
1522 break;
1523 tp->copied_seq = seq;
1524 }
1525 tp->copied_seq = seq;
1526
1527 tcp_rcv_space_adjust(sk);
1528
1529 /* Clean up data we have read: This will do ACK frames. */
1530 if (copied > 0) {
1531 tcp_recv_skb(sk, seq, &offset);
1532 tcp_cleanup_rbuf(sk, copied);
1533 }
1534 return copied;
1535 }
1536 EXPORT_SYMBOL(tcp_read_sock);
1537
1538 /*
1539 * This routine copies from a sock struct into the user buffer.
1540 *
1541 * Technical note: in 2.3 we work on _locked_ socket, so that
1542 * tricks with *seq access order and skb->users are not required.
1543 * Probably, code can be easily improved even more.
1544 */
1545
1546 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1547 size_t len, int nonblock, int flags, int *addr_len)
1548 {
1549 struct tcp_sock *tp = tcp_sk(sk);
1550 int copied = 0;
1551 u32 peek_seq;
1552 u32 *seq;
1553 unsigned long used;
1554 int err;
1555 int target; /* Read at least this many bytes */
1556 long timeo;
1557 struct task_struct *user_recv = NULL;
1558 struct sk_buff *skb;
1559 u32 urg_hole = 0;
1560
1561 if (unlikely(flags & MSG_ERRQUEUE))
1562 return inet_recv_error(sk, msg, len, addr_len);
1563
1564 if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
1565 (sk->sk_state == TCP_ESTABLISHED))
1566 sk_busy_loop(sk, nonblock);
1567
1568 lock_sock(sk);
1569
1570 err = -ENOTCONN;
1571 if (sk->sk_state == TCP_LISTEN)
1572 goto out;
1573
1574 timeo = sock_rcvtimeo(sk, nonblock);
1575
1576 /* Urgent data needs to be handled specially. */
1577 if (flags & MSG_OOB)
1578 goto recv_urg;
1579
1580 if (unlikely(tp->repair)) {
1581 err = -EPERM;
1582 if (!(flags & MSG_PEEK))
1583 goto out;
1584
1585 if (tp->repair_queue == TCP_SEND_QUEUE)
1586 goto recv_sndq;
1587
1588 err = -EINVAL;
1589 if (tp->repair_queue == TCP_NO_QUEUE)
1590 goto out;
1591
1592 /* 'common' recv queue MSG_PEEK-ing */
1593 }
1594
1595 seq = &tp->copied_seq;
1596 if (flags & MSG_PEEK) {
1597 peek_seq = tp->copied_seq;
1598 seq = &peek_seq;
1599 }
1600
1601 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1602
1603 do {
1604 u32 offset;
1605
1606 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1607 if (tp->urg_data && tp->urg_seq == *seq) {
1608 if (copied)
1609 break;
1610 if (signal_pending(current)) {
1611 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1612 break;
1613 }
1614 }
1615
1616 /* Next get a buffer. */
1617
1618 skb_queue_walk(&sk->sk_receive_queue, skb) {
1619 /* Now that we have two receive queues this
1620 * shouldn't happen.
1621 */
1622 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1623 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1624 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1625 flags))
1626 break;
1627
1628 offset = *seq - TCP_SKB_CB(skb)->seq;
1629 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
1630 offset--;
1631 if (offset < skb->len)
1632 goto found_ok_skb;
1633 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1634 goto found_fin_ok;
1635 WARN(!(flags & MSG_PEEK),
1636 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1637 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1638 }
1639
1640 /* Well, if we have backlog, try to process it now yet. */
1641
1642 if (copied >= target && !sk->sk_backlog.tail)
1643 break;
1644
1645 if (copied) {
1646 if (sk->sk_err ||
1647 sk->sk_state == TCP_CLOSE ||
1648 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1649 !timeo ||
1650 signal_pending(current))
1651 break;
1652 } else {
1653 if (sock_flag(sk, SOCK_DONE))
1654 break;
1655
1656 if (sk->sk_err) {
1657 copied = sock_error(sk);
1658 break;
1659 }
1660
1661 if (sk->sk_shutdown & RCV_SHUTDOWN)
1662 break;
1663
1664 if (sk->sk_state == TCP_CLOSE) {
1665 if (!sock_flag(sk, SOCK_DONE)) {
1666 /* This occurs when user tries to read
1667 * from never connected socket.
1668 */
1669 copied = -ENOTCONN;
1670 break;
1671 }
1672 break;
1673 }
1674
1675 if (!timeo) {
1676 copied = -EAGAIN;
1677 break;
1678 }
1679
1680 if (signal_pending(current)) {
1681 copied = sock_intr_errno(timeo);
1682 break;
1683 }
1684 }
1685
1686 tcp_cleanup_rbuf(sk, copied);
1687
1688 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1689 /* Install new reader */
1690 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1691 user_recv = current;
1692 tp->ucopy.task = user_recv;
1693 tp->ucopy.msg = msg;
1694 }
1695
1696 tp->ucopy.len = len;
1697
1698 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1699 !(flags & (MSG_PEEK | MSG_TRUNC)));
1700
1701 /* Ugly... If prequeue is not empty, we have to
1702 * process it before releasing socket, otherwise
1703 * order will be broken at second iteration.
1704 * More elegant solution is required!!!
1705 *
1706 * Look: we have the following (pseudo)queues:
1707 *
1708 * 1. packets in flight
1709 * 2. backlog
1710 * 3. prequeue
1711 * 4. receive_queue
1712 *
1713 * Each queue can be processed only if the next ones
1714 * are empty. At this point we have empty receive_queue.
1715 * But prequeue _can_ be not empty after 2nd iteration,
1716 * when we jumped to start of loop because backlog
1717 * processing added something to receive_queue.
1718 * We cannot release_sock(), because backlog contains
1719 * packets arrived _after_ prequeued ones.
1720 *
1721 * Shortly, algorithm is clear --- to process all
1722 * the queues in order. We could make it more directly,
1723 * requeueing packets from backlog to prequeue, if
1724 * is not empty. It is more elegant, but eats cycles,
1725 * unfortunately.
1726 */
1727 if (!skb_queue_empty(&tp->ucopy.prequeue))
1728 goto do_prequeue;
1729
1730 /* __ Set realtime policy in scheduler __ */
1731 }
1732
1733 if (copied >= target) {
1734 /* Do not sleep, just process backlog. */
1735 release_sock(sk);
1736 lock_sock(sk);
1737 } else
1738 sk_wait_data(sk, &timeo);
1739
1740 if (user_recv) {
1741 int chunk;
1742
1743 /* __ Restore normal policy in scheduler __ */
1744
1745 if ((chunk = len - tp->ucopy.len) != 0) {
1746 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1747 len -= chunk;
1748 copied += chunk;
1749 }
1750
1751 if (tp->rcv_nxt == tp->copied_seq &&
1752 !skb_queue_empty(&tp->ucopy.prequeue)) {
1753 do_prequeue:
1754 tcp_prequeue_process(sk);
1755
1756 if ((chunk = len - tp->ucopy.len) != 0) {
1757 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1758 len -= chunk;
1759 copied += chunk;
1760 }
1761 }
1762 }
1763 if ((flags & MSG_PEEK) &&
1764 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1765 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
1766 current->comm,
1767 task_pid_nr(current));
1768 peek_seq = tp->copied_seq;
1769 }
1770 continue;
1771
1772 found_ok_skb:
1773 /* Ok so how much can we use? */
1774 used = skb->len - offset;
1775 if (len < used)
1776 used = len;
1777
1778 /* Do we have urgent data here? */
1779 if (tp->urg_data) {
1780 u32 urg_offset = tp->urg_seq - *seq;
1781 if (urg_offset < used) {
1782 if (!urg_offset) {
1783 if (!sock_flag(sk, SOCK_URGINLINE)) {
1784 ++*seq;
1785 urg_hole++;
1786 offset++;
1787 used--;
1788 if (!used)
1789 goto skip_copy;
1790 }
1791 } else
1792 used = urg_offset;
1793 }
1794 }
1795
1796 if (!(flags & MSG_TRUNC)) {
1797 err = skb_copy_datagram_msg(skb, offset, msg, used);
1798 if (err) {
1799 /* Exception. Bailout! */
1800 if (!copied)
1801 copied = -EFAULT;
1802 break;
1803 }
1804 }
1805
1806 *seq += used;
1807 copied += used;
1808 len -= used;
1809
1810 tcp_rcv_space_adjust(sk);
1811
1812 skip_copy:
1813 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1814 tp->urg_data = 0;
1815 tcp_fast_path_check(sk);
1816 }
1817 if (used + offset < skb->len)
1818 continue;
1819
1820 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1821 goto found_fin_ok;
1822 if (!(flags & MSG_PEEK))
1823 sk_eat_skb(sk, skb);
1824 continue;
1825
1826 found_fin_ok:
1827 /* Process the FIN. */
1828 ++*seq;
1829 if (!(flags & MSG_PEEK))
1830 sk_eat_skb(sk, skb);
1831 break;
1832 } while (len > 0);
1833
1834 if (user_recv) {
1835 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1836 int chunk;
1837
1838 tp->ucopy.len = copied > 0 ? len : 0;
1839
1840 tcp_prequeue_process(sk);
1841
1842 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1843 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1844 len -= chunk;
1845 copied += chunk;
1846 }
1847 }
1848
1849 tp->ucopy.task = NULL;
1850 tp->ucopy.len = 0;
1851 }
1852
1853 /* According to UNIX98, msg_name/msg_namelen are ignored
1854 * on connected socket. I was just happy when found this 8) --ANK
1855 */
1856
1857 /* Clean up data we have read: This will do ACK frames. */
1858 tcp_cleanup_rbuf(sk, copied);
1859
1860 release_sock(sk);
1861 return copied;
1862
1863 out:
1864 release_sock(sk);
1865 return err;
1866
1867 recv_urg:
1868 err = tcp_recv_urg(sk, msg, len, flags);
1869 goto out;
1870
1871 recv_sndq:
1872 err = tcp_peek_sndq(sk, msg, len);
1873 goto out;
1874 }
1875 EXPORT_SYMBOL(tcp_recvmsg);
1876
1877 void tcp_set_state(struct sock *sk, int state)
1878 {
1879 int oldstate = sk->sk_state;
1880
1881 switch (state) {
1882 case TCP_ESTABLISHED:
1883 if (oldstate != TCP_ESTABLISHED)
1884 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1885 break;
1886
1887 case TCP_CLOSE:
1888 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1889 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1890
1891 sk->sk_prot->unhash(sk);
1892 if (inet_csk(sk)->icsk_bind_hash &&
1893 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1894 inet_put_port(sk);
1895 /* fall through */
1896 default:
1897 if (oldstate == TCP_ESTABLISHED)
1898 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1899 }
1900
1901 /* Change state AFTER socket is unhashed to avoid closed
1902 * socket sitting in hash tables.
1903 */
1904 sk->sk_state = state;
1905
1906 #ifdef STATE_TRACE
1907 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1908 #endif
1909 }
1910 EXPORT_SYMBOL_GPL(tcp_set_state);
1911
1912 /*
1913 * State processing on a close. This implements the state shift for
1914 * sending our FIN frame. Note that we only send a FIN for some
1915 * states. A shutdown() may have already sent the FIN, or we may be
1916 * closed.
1917 */
1918
1919 static const unsigned char new_state[16] = {
1920 /* current state: new state: action: */
1921 /* (Invalid) */ TCP_CLOSE,
1922 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1923 /* TCP_SYN_SENT */ TCP_CLOSE,
1924 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1925 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1926 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1927 /* TCP_TIME_WAIT */ TCP_CLOSE,
1928 /* TCP_CLOSE */ TCP_CLOSE,
1929 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1930 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1931 /* TCP_LISTEN */ TCP_CLOSE,
1932 /* TCP_CLOSING */ TCP_CLOSING,
1933 };
1934
1935 static int tcp_close_state(struct sock *sk)
1936 {
1937 int next = (int)new_state[sk->sk_state];
1938 int ns = next & TCP_STATE_MASK;
1939
1940 tcp_set_state(sk, ns);
1941
1942 return next & TCP_ACTION_FIN;
1943 }
1944
1945 /*
1946 * Shutdown the sending side of a connection. Much like close except
1947 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1948 */
1949
1950 void tcp_shutdown(struct sock *sk, int how)
1951 {
1952 /* We need to grab some memory, and put together a FIN,
1953 * and then put it into the queue to be sent.
1954 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1955 */
1956 if (!(how & SEND_SHUTDOWN))
1957 return;
1958
1959 /* If we've already sent a FIN, or it's a closed state, skip this. */
1960 if ((1 << sk->sk_state) &
1961 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1962 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1963 /* Clear out any half completed packets. FIN if needed. */
1964 if (tcp_close_state(sk))
1965 tcp_send_fin(sk);
1966 }
1967 }
1968 EXPORT_SYMBOL(tcp_shutdown);
1969
1970 bool tcp_check_oom(struct sock *sk, int shift)
1971 {
1972 bool too_many_orphans, out_of_socket_memory;
1973
1974 too_many_orphans = tcp_too_many_orphans(sk, shift);
1975 out_of_socket_memory = tcp_out_of_memory(sk);
1976
1977 if (too_many_orphans)
1978 net_info_ratelimited("too many orphaned sockets\n");
1979 if (out_of_socket_memory)
1980 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
1981 return too_many_orphans || out_of_socket_memory;
1982 }
1983
1984 void tcp_close(struct sock *sk, long timeout)
1985 {
1986 struct sk_buff *skb;
1987 int data_was_unread = 0;
1988 int state;
1989
1990 lock_sock(sk);
1991 sk->sk_shutdown = SHUTDOWN_MASK;
1992
1993 if (sk->sk_state == TCP_LISTEN) {
1994 tcp_set_state(sk, TCP_CLOSE);
1995
1996 /* Special case. */
1997 inet_csk_listen_stop(sk);
1998
1999 goto adjudge_to_death;
2000 }
2001
2002 /* We need to flush the recv. buffs. We do this only on the
2003 * descriptor close, not protocol-sourced closes, because the
2004 * reader process may not have drained the data yet!
2005 */
2006 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2007 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
2008
2009 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2010 len--;
2011 data_was_unread += len;
2012 __kfree_skb(skb);
2013 }
2014
2015 sk_mem_reclaim(sk);
2016
2017 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2018 if (sk->sk_state == TCP_CLOSE)
2019 goto adjudge_to_death;
2020
2021 /* As outlined in RFC 2525, section 2.17, we send a RST here because
2022 * data was lost. To witness the awful effects of the old behavior of
2023 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2024 * GET in an FTP client, suspend the process, wait for the client to
2025 * advertise a zero window, then kill -9 the FTP client, wheee...
2026 * Note: timeout is always zero in such a case.
2027 */
2028 if (unlikely(tcp_sk(sk)->repair)) {
2029 sk->sk_prot->disconnect(sk, 0);
2030 } else if (data_was_unread) {
2031 /* Unread data was tossed, zap the connection. */
2032 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2033 tcp_set_state(sk, TCP_CLOSE);
2034 tcp_send_active_reset(sk, sk->sk_allocation);
2035 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2036 /* Check zero linger _after_ checking for unread data. */
2037 sk->sk_prot->disconnect(sk, 0);
2038 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2039 } else if (tcp_close_state(sk)) {
2040 /* We FIN if the application ate all the data before
2041 * zapping the connection.
2042 */
2043
2044 /* RED-PEN. Formally speaking, we have broken TCP state
2045 * machine. State transitions:
2046 *
2047 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2048 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2049 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2050 *
2051 * are legal only when FIN has been sent (i.e. in window),
2052 * rather than queued out of window. Purists blame.
2053 *
2054 * F.e. "RFC state" is ESTABLISHED,
2055 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2056 *
2057 * The visible declinations are that sometimes
2058 * we enter time-wait state, when it is not required really
2059 * (harmless), do not send active resets, when they are
2060 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2061 * they look as CLOSING or LAST_ACK for Linux)
2062 * Probably, I missed some more holelets.
2063 * --ANK
2064 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2065 * in a single packet! (May consider it later but will
2066 * probably need API support or TCP_CORK SYN-ACK until
2067 * data is written and socket is closed.)
2068 */
2069 tcp_send_fin(sk);
2070 }
2071
2072 sk_stream_wait_close(sk, timeout);
2073
2074 adjudge_to_death:
2075 state = sk->sk_state;
2076 sock_hold(sk);
2077 sock_orphan(sk);
2078
2079 /* It is the last release_sock in its life. It will remove backlog. */
2080 release_sock(sk);
2081
2082
2083 /* Now socket is owned by kernel and we acquire BH lock
2084 to finish close. No need to check for user refs.
2085 */
2086 local_bh_disable();
2087 bh_lock_sock(sk);
2088 WARN_ON(sock_owned_by_user(sk));
2089
2090 percpu_counter_inc(sk->sk_prot->orphan_count);
2091
2092 /* Have we already been destroyed by a softirq or backlog? */
2093 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2094 goto out;
2095
2096 /* This is a (useful) BSD violating of the RFC. There is a
2097 * problem with TCP as specified in that the other end could
2098 * keep a socket open forever with no application left this end.
2099 * We use a 1 minute timeout (about the same as BSD) then kill
2100 * our end. If they send after that then tough - BUT: long enough
2101 * that we won't make the old 4*rto = almost no time - whoops
2102 * reset mistake.
2103 *
2104 * Nope, it was not mistake. It is really desired behaviour
2105 * f.e. on http servers, when such sockets are useless, but
2106 * consume significant resources. Let's do it with special
2107 * linger2 option. --ANK
2108 */
2109
2110 if (sk->sk_state == TCP_FIN_WAIT2) {
2111 struct tcp_sock *tp = tcp_sk(sk);
2112 if (tp->linger2 < 0) {
2113 tcp_set_state(sk, TCP_CLOSE);
2114 tcp_send_active_reset(sk, GFP_ATOMIC);
2115 NET_INC_STATS_BH(sock_net(sk),
2116 LINUX_MIB_TCPABORTONLINGER);
2117 } else {
2118 const int tmo = tcp_fin_time(sk);
2119
2120 if (tmo > TCP_TIMEWAIT_LEN) {
2121 inet_csk_reset_keepalive_timer(sk,
2122 tmo - TCP_TIMEWAIT_LEN);
2123 } else {
2124 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2125 goto out;
2126 }
2127 }
2128 }
2129 if (sk->sk_state != TCP_CLOSE) {
2130 sk_mem_reclaim(sk);
2131 if (tcp_check_oom(sk, 0)) {
2132 tcp_set_state(sk, TCP_CLOSE);
2133 tcp_send_active_reset(sk, GFP_ATOMIC);
2134 NET_INC_STATS_BH(sock_net(sk),
2135 LINUX_MIB_TCPABORTONMEMORY);
2136 }
2137 }
2138
2139 if (sk->sk_state == TCP_CLOSE) {
2140 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2141 /* We could get here with a non-NULL req if the socket is
2142 * aborted (e.g., closed with unread data) before 3WHS
2143 * finishes.
2144 */
2145 if (req != NULL)
2146 reqsk_fastopen_remove(sk, req, false);
2147 inet_csk_destroy_sock(sk);
2148 }
2149 /* Otherwise, socket is reprieved until protocol close. */
2150
2151 out:
2152 bh_unlock_sock(sk);
2153 local_bh_enable();
2154 sock_put(sk);
2155 }
2156 EXPORT_SYMBOL(tcp_close);
2157
2158 /* These states need RST on ABORT according to RFC793 */
2159
2160 static inline bool tcp_need_reset(int state)
2161 {
2162 return (1 << state) &
2163 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2164 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2165 }
2166
2167 int tcp_disconnect(struct sock *sk, int flags)
2168 {
2169 struct inet_sock *inet = inet_sk(sk);
2170 struct inet_connection_sock *icsk = inet_csk(sk);
2171 struct tcp_sock *tp = tcp_sk(sk);
2172 int err = 0;
2173 int old_state = sk->sk_state;
2174
2175 if (old_state != TCP_CLOSE)
2176 tcp_set_state(sk, TCP_CLOSE);
2177
2178 /* ABORT function of RFC793 */
2179 if (old_state == TCP_LISTEN) {
2180 inet_csk_listen_stop(sk);
2181 } else if (unlikely(tp->repair)) {
2182 sk->sk_err = ECONNABORTED;
2183 } else if (tcp_need_reset(old_state) ||
2184 (tp->snd_nxt != tp->write_seq &&
2185 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2186 /* The last check adjusts for discrepancy of Linux wrt. RFC
2187 * states
2188 */
2189 tcp_send_active_reset(sk, gfp_any());
2190 sk->sk_err = ECONNRESET;
2191 } else if (old_state == TCP_SYN_SENT)
2192 sk->sk_err = ECONNRESET;
2193
2194 tcp_clear_xmit_timers(sk);
2195 __skb_queue_purge(&sk->sk_receive_queue);
2196 tcp_write_queue_purge(sk);
2197 __skb_queue_purge(&tp->out_of_order_queue);
2198
2199 inet->inet_dport = 0;
2200
2201 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2202 inet_reset_saddr(sk);
2203
2204 sk->sk_shutdown = 0;
2205 sock_reset_flag(sk, SOCK_DONE);
2206 tp->srtt_us = 0;
2207 if ((tp->write_seq += tp->max_window + 2) == 0)
2208 tp->write_seq = 1;
2209 icsk->icsk_backoff = 0;
2210 tp->snd_cwnd = 2;
2211 icsk->icsk_probes_out = 0;
2212 tp->packets_out = 0;
2213 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2214 tp->snd_cwnd_cnt = 0;
2215 tp->window_clamp = 0;
2216 tcp_set_ca_state(sk, TCP_CA_Open);
2217 tcp_clear_retrans(tp);
2218 inet_csk_delack_init(sk);
2219 tcp_init_send_head(sk);
2220 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2221 __sk_dst_reset(sk);
2222
2223 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2224
2225 sk->sk_error_report(sk);
2226 return err;
2227 }
2228 EXPORT_SYMBOL(tcp_disconnect);
2229
2230 void tcp_sock_destruct(struct sock *sk)
2231 {
2232 inet_sock_destruct(sk);
2233
2234 kfree(inet_csk(sk)->icsk_accept_queue.fastopenq);
2235 }
2236
2237 static inline bool tcp_can_repair_sock(const struct sock *sk)
2238 {
2239 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
2240 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
2241 }
2242
2243 static int tcp_repair_options_est(struct tcp_sock *tp,
2244 struct tcp_repair_opt __user *optbuf, unsigned int len)
2245 {
2246 struct tcp_repair_opt opt;
2247
2248 while (len >= sizeof(opt)) {
2249 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2250 return -EFAULT;
2251
2252 optbuf++;
2253 len -= sizeof(opt);
2254
2255 switch (opt.opt_code) {
2256 case TCPOPT_MSS:
2257 tp->rx_opt.mss_clamp = opt.opt_val;
2258 break;
2259 case TCPOPT_WINDOW:
2260 {
2261 u16 snd_wscale = opt.opt_val & 0xFFFF;
2262 u16 rcv_wscale = opt.opt_val >> 16;
2263
2264 if (snd_wscale > 14 || rcv_wscale > 14)
2265 return -EFBIG;
2266
2267 tp->rx_opt.snd_wscale = snd_wscale;
2268 tp->rx_opt.rcv_wscale = rcv_wscale;
2269 tp->rx_opt.wscale_ok = 1;
2270 }
2271 break;
2272 case TCPOPT_SACK_PERM:
2273 if (opt.opt_val != 0)
2274 return -EINVAL;
2275
2276 tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2277 if (sysctl_tcp_fack)
2278 tcp_enable_fack(tp);
2279 break;
2280 case TCPOPT_TIMESTAMP:
2281 if (opt.opt_val != 0)
2282 return -EINVAL;
2283
2284 tp->rx_opt.tstamp_ok = 1;
2285 break;
2286 }
2287 }
2288
2289 return 0;
2290 }
2291
2292 /*
2293 * Socket option code for TCP.
2294 */
2295 static int do_tcp_setsockopt(struct sock *sk, int level,
2296 int optname, char __user *optval, unsigned int optlen)
2297 {
2298 struct tcp_sock *tp = tcp_sk(sk);
2299 struct inet_connection_sock *icsk = inet_csk(sk);
2300 int val;
2301 int err = 0;
2302
2303 /* These are data/string values, all the others are ints */
2304 switch (optname) {
2305 case TCP_CONGESTION: {
2306 char name[TCP_CA_NAME_MAX];
2307
2308 if (optlen < 1)
2309 return -EINVAL;
2310
2311 val = strncpy_from_user(name, optval,
2312 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2313 if (val < 0)
2314 return -EFAULT;
2315 name[val] = 0;
2316
2317 lock_sock(sk);
2318 err = tcp_set_congestion_control(sk, name);
2319 release_sock(sk);
2320 return err;
2321 }
2322 default:
2323 /* fallthru */
2324 break;
2325 }
2326
2327 if (optlen < sizeof(int))
2328 return -EINVAL;
2329
2330 if (get_user(val, (int __user *)optval))
2331 return -EFAULT;
2332
2333 lock_sock(sk);
2334
2335 switch (optname) {
2336 case TCP_MAXSEG:
2337 /* Values greater than interface MTU won't take effect. However
2338 * at the point when this call is done we typically don't yet
2339 * know which interface is going to be used */
2340 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2341 err = -EINVAL;
2342 break;
2343 }
2344 tp->rx_opt.user_mss = val;
2345 break;
2346
2347 case TCP_NODELAY:
2348 if (val) {
2349 /* TCP_NODELAY is weaker than TCP_CORK, so that
2350 * this option on corked socket is remembered, but
2351 * it is not activated until cork is cleared.
2352 *
2353 * However, when TCP_NODELAY is set we make
2354 * an explicit push, which overrides even TCP_CORK
2355 * for currently queued segments.
2356 */
2357 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2358 tcp_push_pending_frames(sk);
2359 } else {
2360 tp->nonagle &= ~TCP_NAGLE_OFF;
2361 }
2362 break;
2363
2364 case TCP_THIN_LINEAR_TIMEOUTS:
2365 if (val < 0 || val > 1)
2366 err = -EINVAL;
2367 else
2368 tp->thin_lto = val;
2369 break;
2370
2371 case TCP_THIN_DUPACK:
2372 if (val < 0 || val > 1)
2373 err = -EINVAL;
2374 else {
2375 tp->thin_dupack = val;
2376 if (tp->thin_dupack)
2377 tcp_disable_early_retrans(tp);
2378 }
2379 break;
2380
2381 case TCP_REPAIR:
2382 if (!tcp_can_repair_sock(sk))
2383 err = -EPERM;
2384 else if (val == 1) {
2385 tp->repair = 1;
2386 sk->sk_reuse = SK_FORCE_REUSE;
2387 tp->repair_queue = TCP_NO_QUEUE;
2388 } else if (val == 0) {
2389 tp->repair = 0;
2390 sk->sk_reuse = SK_NO_REUSE;
2391 tcp_send_window_probe(sk);
2392 } else
2393 err = -EINVAL;
2394
2395 break;
2396
2397 case TCP_REPAIR_QUEUE:
2398 if (!tp->repair)
2399 err = -EPERM;
2400 else if (val < TCP_QUEUES_NR)
2401 tp->repair_queue = val;
2402 else
2403 err = -EINVAL;
2404 break;
2405
2406 case TCP_QUEUE_SEQ:
2407 if (sk->sk_state != TCP_CLOSE)
2408 err = -EPERM;
2409 else if (tp->repair_queue == TCP_SEND_QUEUE)
2410 tp->write_seq = val;
2411 else if (tp->repair_queue == TCP_RECV_QUEUE)
2412 tp->rcv_nxt = val;
2413 else
2414 err = -EINVAL;
2415 break;
2416
2417 case TCP_REPAIR_OPTIONS:
2418 if (!tp->repair)
2419 err = -EINVAL;
2420 else if (sk->sk_state == TCP_ESTABLISHED)
2421 err = tcp_repair_options_est(tp,
2422 (struct tcp_repair_opt __user *)optval,
2423 optlen);
2424 else
2425 err = -EPERM;
2426 break;
2427
2428 case TCP_CORK:
2429 /* When set indicates to always queue non-full frames.
2430 * Later the user clears this option and we transmit
2431 * any pending partial frames in the queue. This is
2432 * meant to be used alongside sendfile() to get properly
2433 * filled frames when the user (for example) must write
2434 * out headers with a write() call first and then use
2435 * sendfile to send out the data parts.
2436 *
2437 * TCP_CORK can be set together with TCP_NODELAY and it is
2438 * stronger than TCP_NODELAY.
2439 */
2440 if (val) {
2441 tp->nonagle |= TCP_NAGLE_CORK;
2442 } else {
2443 tp->nonagle &= ~TCP_NAGLE_CORK;
2444 if (tp->nonagle&TCP_NAGLE_OFF)
2445 tp->nonagle |= TCP_NAGLE_PUSH;
2446 tcp_push_pending_frames(sk);
2447 }
2448 break;
2449
2450 case TCP_KEEPIDLE:
2451 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2452 err = -EINVAL;
2453 else {
2454 tp->keepalive_time = val * HZ;
2455 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2456 !((1 << sk->sk_state) &
2457 (TCPF_CLOSE | TCPF_LISTEN))) {
2458 u32 elapsed = keepalive_time_elapsed(tp);
2459 if (tp->keepalive_time > elapsed)
2460 elapsed = tp->keepalive_time - elapsed;
2461 else
2462 elapsed = 0;
2463 inet_csk_reset_keepalive_timer(sk, elapsed);
2464 }
2465 }
2466 break;
2467 case TCP_KEEPINTVL:
2468 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2469 err = -EINVAL;
2470 else
2471 tp->keepalive_intvl = val * HZ;
2472 break;
2473 case TCP_KEEPCNT:
2474 if (val < 1 || val > MAX_TCP_KEEPCNT)
2475 err = -EINVAL;
2476 else
2477 tp->keepalive_probes = val;
2478 break;
2479 case TCP_SYNCNT:
2480 if (val < 1 || val > MAX_TCP_SYNCNT)
2481 err = -EINVAL;
2482 else
2483 icsk->icsk_syn_retries = val;
2484 break;
2485
2486 case TCP_LINGER2:
2487 if (val < 0)
2488 tp->linger2 = -1;
2489 else if (val > sysctl_tcp_fin_timeout / HZ)
2490 tp->linger2 = 0;
2491 else
2492 tp->linger2 = val * HZ;
2493 break;
2494
2495 case TCP_DEFER_ACCEPT:
2496 /* Translate value in seconds to number of retransmits */
2497 icsk->icsk_accept_queue.rskq_defer_accept =
2498 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2499 TCP_RTO_MAX / HZ);
2500 break;
2501
2502 case TCP_WINDOW_CLAMP:
2503 if (!val) {
2504 if (sk->sk_state != TCP_CLOSE) {
2505 err = -EINVAL;
2506 break;
2507 }
2508 tp->window_clamp = 0;
2509 } else
2510 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2511 SOCK_MIN_RCVBUF / 2 : val;
2512 break;
2513
2514 case TCP_QUICKACK:
2515 if (!val) {
2516 icsk->icsk_ack.pingpong = 1;
2517 } else {
2518 icsk->icsk_ack.pingpong = 0;
2519 if ((1 << sk->sk_state) &
2520 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2521 inet_csk_ack_scheduled(sk)) {
2522 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2523 tcp_cleanup_rbuf(sk, 1);
2524 if (!(val & 1))
2525 icsk->icsk_ack.pingpong = 1;
2526 }
2527 }
2528 break;
2529
2530 #ifdef CONFIG_TCP_MD5SIG
2531 case TCP_MD5SIG:
2532 /* Read the IP->Key mappings from userspace */
2533 err = tp->af_specific->md5_parse(sk, optval, optlen);
2534 break;
2535 #endif
2536 case TCP_USER_TIMEOUT:
2537 /* Cap the max time in ms TCP will retry or probe the window
2538 * before giving up and aborting (ETIMEDOUT) a connection.
2539 */
2540 if (val < 0)
2541 err = -EINVAL;
2542 else
2543 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2544 break;
2545
2546 case TCP_FASTOPEN:
2547 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2548 TCPF_LISTEN)))
2549 err = fastopen_init_queue(sk, val);
2550 else
2551 err = -EINVAL;
2552 break;
2553 case TCP_TIMESTAMP:
2554 if (!tp->repair)
2555 err = -EPERM;
2556 else
2557 tp->tsoffset = val - tcp_time_stamp;
2558 break;
2559 case TCP_NOTSENT_LOWAT:
2560 tp->notsent_lowat = val;
2561 sk->sk_write_space(sk);
2562 break;
2563 default:
2564 err = -ENOPROTOOPT;
2565 break;
2566 }
2567
2568 release_sock(sk);
2569 return err;
2570 }
2571
2572 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2573 unsigned int optlen)
2574 {
2575 const struct inet_connection_sock *icsk = inet_csk(sk);
2576
2577 if (level != SOL_TCP)
2578 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2579 optval, optlen);
2580 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2581 }
2582 EXPORT_SYMBOL(tcp_setsockopt);
2583
2584 #ifdef CONFIG_COMPAT
2585 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2586 char __user *optval, unsigned int optlen)
2587 {
2588 if (level != SOL_TCP)
2589 return inet_csk_compat_setsockopt(sk, level, optname,
2590 optval, optlen);
2591 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2592 }
2593 EXPORT_SYMBOL(compat_tcp_setsockopt);
2594 #endif
2595
2596 /* Return information about state of tcp endpoint in API format. */
2597 void tcp_get_info(const struct sock *sk, struct tcp_info *info)
2598 {
2599 const struct tcp_sock *tp = tcp_sk(sk);
2600 const struct inet_connection_sock *icsk = inet_csk(sk);
2601 u32 now = tcp_time_stamp;
2602
2603 memset(info, 0, sizeof(*info));
2604
2605 info->tcpi_state = sk->sk_state;
2606 info->tcpi_ca_state = icsk->icsk_ca_state;
2607 info->tcpi_retransmits = icsk->icsk_retransmits;
2608 info->tcpi_probes = icsk->icsk_probes_out;
2609 info->tcpi_backoff = icsk->icsk_backoff;
2610
2611 if (tp->rx_opt.tstamp_ok)
2612 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2613 if (tcp_is_sack(tp))
2614 info->tcpi_options |= TCPI_OPT_SACK;
2615 if (tp->rx_opt.wscale_ok) {
2616 info->tcpi_options |= TCPI_OPT_WSCALE;
2617 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2618 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2619 }
2620
2621 if (tp->ecn_flags & TCP_ECN_OK)
2622 info->tcpi_options |= TCPI_OPT_ECN;
2623 if (tp->ecn_flags & TCP_ECN_SEEN)
2624 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2625 if (tp->syn_data_acked)
2626 info->tcpi_options |= TCPI_OPT_SYN_DATA;
2627
2628 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2629 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2630 info->tcpi_snd_mss = tp->mss_cache;
2631 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2632
2633 if (sk->sk_state == TCP_LISTEN) {
2634 info->tcpi_unacked = sk->sk_ack_backlog;
2635 info->tcpi_sacked = sk->sk_max_ack_backlog;
2636 } else {
2637 info->tcpi_unacked = tp->packets_out;
2638 info->tcpi_sacked = tp->sacked_out;
2639 }
2640 info->tcpi_lost = tp->lost_out;
2641 info->tcpi_retrans = tp->retrans_out;
2642 info->tcpi_fackets = tp->fackets_out;
2643
2644 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2645 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2646 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2647
2648 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2649 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2650 info->tcpi_rtt = tp->srtt_us >> 3;
2651 info->tcpi_rttvar = tp->mdev_us >> 2;
2652 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2653 info->tcpi_snd_cwnd = tp->snd_cwnd;
2654 info->tcpi_advmss = tp->advmss;
2655 info->tcpi_reordering = tp->reordering;
2656
2657 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2658 info->tcpi_rcv_space = tp->rcvq_space.space;
2659
2660 info->tcpi_total_retrans = tp->total_retrans;
2661
2662 info->tcpi_pacing_rate = sk->sk_pacing_rate != ~0U ?
2663 sk->sk_pacing_rate : ~0ULL;
2664 info->tcpi_max_pacing_rate = sk->sk_max_pacing_rate != ~0U ?
2665 sk->sk_max_pacing_rate : ~0ULL;
2666 }
2667 EXPORT_SYMBOL_GPL(tcp_get_info);
2668
2669 static int do_tcp_getsockopt(struct sock *sk, int level,
2670 int optname, char __user *optval, int __user *optlen)
2671 {
2672 struct inet_connection_sock *icsk = inet_csk(sk);
2673 struct tcp_sock *tp = tcp_sk(sk);
2674 int val, len;
2675
2676 if (get_user(len, optlen))
2677 return -EFAULT;
2678
2679 len = min_t(unsigned int, len, sizeof(int));
2680
2681 if (len < 0)
2682 return -EINVAL;
2683
2684 switch (optname) {
2685 case TCP_MAXSEG:
2686 val = tp->mss_cache;
2687 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2688 val = tp->rx_opt.user_mss;
2689 if (tp->repair)
2690 val = tp->rx_opt.mss_clamp;
2691 break;
2692 case TCP_NODELAY:
2693 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2694 break;
2695 case TCP_CORK:
2696 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2697 break;
2698 case TCP_KEEPIDLE:
2699 val = keepalive_time_when(tp) / HZ;
2700 break;
2701 case TCP_KEEPINTVL:
2702 val = keepalive_intvl_when(tp) / HZ;
2703 break;
2704 case TCP_KEEPCNT:
2705 val = keepalive_probes(tp);
2706 break;
2707 case TCP_SYNCNT:
2708 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2709 break;
2710 case TCP_LINGER2:
2711 val = tp->linger2;
2712 if (val >= 0)
2713 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2714 break;
2715 case TCP_DEFER_ACCEPT:
2716 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2717 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2718 break;
2719 case TCP_WINDOW_CLAMP:
2720 val = tp->window_clamp;
2721 break;
2722 case TCP_INFO: {
2723 struct tcp_info info;
2724
2725 if (get_user(len, optlen))
2726 return -EFAULT;
2727
2728 tcp_get_info(sk, &info);
2729
2730 len = min_t(unsigned int, len, sizeof(info));
2731 if (put_user(len, optlen))
2732 return -EFAULT;
2733 if (copy_to_user(optval, &info, len))
2734 return -EFAULT;
2735 return 0;
2736 }
2737 case TCP_QUICKACK:
2738 val = !icsk->icsk_ack.pingpong;
2739 break;
2740
2741 case TCP_CONGESTION:
2742 if (get_user(len, optlen))
2743 return -EFAULT;
2744 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2745 if (put_user(len, optlen))
2746 return -EFAULT;
2747 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2748 return -EFAULT;
2749 return 0;
2750
2751 case TCP_THIN_LINEAR_TIMEOUTS:
2752 val = tp->thin_lto;
2753 break;
2754 case TCP_THIN_DUPACK:
2755 val = tp->thin_dupack;
2756 break;
2757
2758 case TCP_REPAIR:
2759 val = tp->repair;
2760 break;
2761
2762 case TCP_REPAIR_QUEUE:
2763 if (tp->repair)
2764 val = tp->repair_queue;
2765 else
2766 return -EINVAL;
2767 break;
2768
2769 case TCP_QUEUE_SEQ:
2770 if (tp->repair_queue == TCP_SEND_QUEUE)
2771 val = tp->write_seq;
2772 else if (tp->repair_queue == TCP_RECV_QUEUE)
2773 val = tp->rcv_nxt;
2774 else
2775 return -EINVAL;
2776 break;
2777
2778 case TCP_USER_TIMEOUT:
2779 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2780 break;
2781
2782 case TCP_FASTOPEN:
2783 if (icsk->icsk_accept_queue.fastopenq != NULL)
2784 val = icsk->icsk_accept_queue.fastopenq->max_qlen;
2785 else
2786 val = 0;
2787 break;
2788
2789 case TCP_TIMESTAMP:
2790 val = tcp_time_stamp + tp->tsoffset;
2791 break;
2792 case TCP_NOTSENT_LOWAT:
2793 val = tp->notsent_lowat;
2794 break;
2795 default:
2796 return -ENOPROTOOPT;
2797 }
2798
2799 if (put_user(len, optlen))
2800 return -EFAULT;
2801 if (copy_to_user(optval, &val, len))
2802 return -EFAULT;
2803 return 0;
2804 }
2805
2806 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2807 int __user *optlen)
2808 {
2809 struct inet_connection_sock *icsk = inet_csk(sk);
2810
2811 if (level != SOL_TCP)
2812 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2813 optval, optlen);
2814 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2815 }
2816 EXPORT_SYMBOL(tcp_getsockopt);
2817
2818 #ifdef CONFIG_COMPAT
2819 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2820 char __user *optval, int __user *optlen)
2821 {
2822 if (level != SOL_TCP)
2823 return inet_csk_compat_getsockopt(sk, level, optname,
2824 optval, optlen);
2825 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2826 }
2827 EXPORT_SYMBOL(compat_tcp_getsockopt);
2828 #endif
2829
2830 #ifdef CONFIG_TCP_MD5SIG
2831 static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
2832 static DEFINE_MUTEX(tcp_md5sig_mutex);
2833 static bool tcp_md5sig_pool_populated = false;
2834
2835 static void __tcp_alloc_md5sig_pool(void)
2836 {
2837 int cpu;
2838
2839 for_each_possible_cpu(cpu) {
2840 if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) {
2841 struct crypto_hash *hash;
2842
2843 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2844 if (IS_ERR_OR_NULL(hash))
2845 return;
2846 per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm = hash;
2847 }
2848 }
2849 /* before setting tcp_md5sig_pool_populated, we must commit all writes
2850 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
2851 */
2852 smp_wmb();
2853 tcp_md5sig_pool_populated = true;
2854 }
2855
2856 bool tcp_alloc_md5sig_pool(void)
2857 {
2858 if (unlikely(!tcp_md5sig_pool_populated)) {
2859 mutex_lock(&tcp_md5sig_mutex);
2860
2861 if (!tcp_md5sig_pool_populated)
2862 __tcp_alloc_md5sig_pool();
2863
2864 mutex_unlock(&tcp_md5sig_mutex);
2865 }
2866 return tcp_md5sig_pool_populated;
2867 }
2868 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2869
2870
2871 /**
2872 * tcp_get_md5sig_pool - get md5sig_pool for this user
2873 *
2874 * We use percpu structure, so if we succeed, we exit with preemption
2875 * and BH disabled, to make sure another thread or softirq handling
2876 * wont try to get same context.
2877 */
2878 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2879 {
2880 local_bh_disable();
2881
2882 if (tcp_md5sig_pool_populated) {
2883 /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
2884 smp_rmb();
2885 return this_cpu_ptr(&tcp_md5sig_pool);
2886 }
2887 local_bh_enable();
2888 return NULL;
2889 }
2890 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2891
2892 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2893 const struct tcphdr *th)
2894 {
2895 struct scatterlist sg;
2896 struct tcphdr hdr;
2897 int err;
2898
2899 /* We are not allowed to change tcphdr, make a local copy */
2900 memcpy(&hdr, th, sizeof(hdr));
2901 hdr.check = 0;
2902
2903 /* options aren't included in the hash */
2904 sg_init_one(&sg, &hdr, sizeof(hdr));
2905 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
2906 return err;
2907 }
2908 EXPORT_SYMBOL(tcp_md5_hash_header);
2909
2910 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2911 const struct sk_buff *skb, unsigned int header_len)
2912 {
2913 struct scatterlist sg;
2914 const struct tcphdr *tp = tcp_hdr(skb);
2915 struct hash_desc *desc = &hp->md5_desc;
2916 unsigned int i;
2917 const unsigned int head_data_len = skb_headlen(skb) > header_len ?
2918 skb_headlen(skb) - header_len : 0;
2919 const struct skb_shared_info *shi = skb_shinfo(skb);
2920 struct sk_buff *frag_iter;
2921
2922 sg_init_table(&sg, 1);
2923
2924 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2925 if (crypto_hash_update(desc, &sg, head_data_len))
2926 return 1;
2927
2928 for (i = 0; i < shi->nr_frags; ++i) {
2929 const struct skb_frag_struct *f = &shi->frags[i];
2930 unsigned int offset = f->page_offset;
2931 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
2932
2933 sg_set_page(&sg, page, skb_frag_size(f),
2934 offset_in_page(offset));
2935 if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
2936 return 1;
2937 }
2938
2939 skb_walk_frags(skb, frag_iter)
2940 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
2941 return 1;
2942
2943 return 0;
2944 }
2945 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
2946
2947 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
2948 {
2949 struct scatterlist sg;
2950
2951 sg_init_one(&sg, key->key, key->keylen);
2952 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
2953 }
2954 EXPORT_SYMBOL(tcp_md5_hash_key);
2955
2956 #endif
2957
2958 void tcp_done(struct sock *sk)
2959 {
2960 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2961
2962 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2963 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
2964
2965 tcp_set_state(sk, TCP_CLOSE);
2966 tcp_clear_xmit_timers(sk);
2967 if (req != NULL)
2968 reqsk_fastopen_remove(sk, req, false);
2969
2970 sk->sk_shutdown = SHUTDOWN_MASK;
2971
2972 if (!sock_flag(sk, SOCK_DEAD))
2973 sk->sk_state_change(sk);
2974 else
2975 inet_csk_destroy_sock(sk);
2976 }
2977 EXPORT_SYMBOL_GPL(tcp_done);
2978
2979 extern struct tcp_congestion_ops tcp_reno;
2980
2981 static __initdata unsigned long thash_entries;
2982 static int __init set_thash_entries(char *str)
2983 {
2984 ssize_t ret;
2985
2986 if (!str)
2987 return 0;
2988
2989 ret = kstrtoul(str, 0, &thash_entries);
2990 if (ret)
2991 return 0;
2992
2993 return 1;
2994 }
2995 __setup("thash_entries=", set_thash_entries);
2996
2997 static void __init tcp_init_mem(void)
2998 {
2999 unsigned long limit = nr_free_buffer_pages() / 8;
3000 limit = max(limit, 128UL);
3001 sysctl_tcp_mem[0] = limit / 4 * 3;
3002 sysctl_tcp_mem[1] = limit;
3003 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3004 }
3005
3006 void __init tcp_init(void)
3007 {
3008 struct sk_buff *skb = NULL;
3009 unsigned long limit;
3010 int max_rshare, max_wshare, cnt;
3011 unsigned int i;
3012
3013 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3014
3015 percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
3016 percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3017 tcp_hashinfo.bind_bucket_cachep =
3018 kmem_cache_create("tcp_bind_bucket",
3019 sizeof(struct inet_bind_bucket), 0,
3020 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3021
3022 /* Size and allocate the main established and bind bucket
3023 * hash tables.
3024 *
3025 * The methodology is similar to that of the buffer cache.
3026 */
3027 tcp_hashinfo.ehash =
3028 alloc_large_system_hash("TCP established",
3029 sizeof(struct inet_ehash_bucket),
3030 thash_entries,
3031 17, /* one slot per 128 KB of memory */
3032 0,
3033 NULL,
3034 &tcp_hashinfo.ehash_mask,
3035 0,
3036 thash_entries ? 0 : 512 * 1024);
3037 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3038 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3039
3040 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3041 panic("TCP: failed to alloc ehash_locks");
3042 tcp_hashinfo.bhash =
3043 alloc_large_system_hash("TCP bind",
3044 sizeof(struct inet_bind_hashbucket),
3045 tcp_hashinfo.ehash_mask + 1,
3046 17, /* one slot per 128 KB of memory */
3047 0,
3048 &tcp_hashinfo.bhash_size,
3049 NULL,
3050 0,
3051 64 * 1024);
3052 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3053 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3054 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3055 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3056 }
3057
3058
3059 cnt = tcp_hashinfo.ehash_mask + 1;
3060
3061 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3062 sysctl_tcp_max_orphans = cnt / 2;
3063 sysctl_max_syn_backlog = max(128, cnt / 256);
3064
3065 tcp_init_mem();
3066 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3067 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3068 max_wshare = min(4UL*1024*1024, limit);
3069 max_rshare = min(6UL*1024*1024, limit);
3070
3071 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3072 sysctl_tcp_wmem[1] = 16*1024;
3073 sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3074
3075 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3076 sysctl_tcp_rmem[1] = 87380;
3077 sysctl_tcp_rmem[2] = max(87380, max_rshare);
3078
3079 pr_info("Hash tables configured (established %u bind %u)\n",
3080 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3081
3082 tcp_metrics_init();
3083 BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
3084 tcp_tasklet_init();
3085 }
Linux kernel - Deliverables
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