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Merge remote-tracking branches 'spi/fix/dw', 'spi/fix/queue' and 'spi/fix/qup' into...
[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;
839
840 if (!large_allowed || !sk_can_gso(sk))
841 return mss_now;
842
843 /* Note : tcp_tso_autosize() will eventually split this later */
844 new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER;
845 new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);
846
847 /* We try hard to avoid divides here */
848 size_goal = tp->gso_segs * mss_now;
849 if (unlikely(new_size_goal < size_goal ||
850 new_size_goal >= size_goal + mss_now)) {
851 tp->gso_segs = min_t(u16, new_size_goal / mss_now,
852 sk->sk_gso_max_segs);
853 size_goal = tp->gso_segs * mss_now;
854 }
855
856 return max(size_goal, mss_now);
857 }
858
859 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
860 {
861 int mss_now;
862
863 mss_now = tcp_current_mss(sk);
864 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
865
866 return mss_now;
867 }
868
869 static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
870 size_t size, int flags)
871 {
872 struct tcp_sock *tp = tcp_sk(sk);
873 int mss_now, size_goal;
874 int err;
875 ssize_t copied;
876 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
877
878 /* Wait for a connection to finish. One exception is TCP Fast Open
879 * (passive side) where data is allowed to be sent before a connection
880 * is fully established.
881 */
882 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
883 !tcp_passive_fastopen(sk)) {
884 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
885 goto out_err;
886 }
887
888 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
889
890 mss_now = tcp_send_mss(sk, &size_goal, flags);
891 copied = 0;
892
893 err = -EPIPE;
894 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
895 goto out_err;
896
897 while (size > 0) {
898 struct sk_buff *skb = tcp_write_queue_tail(sk);
899 int copy, i;
900 bool can_coalesce;
901
902 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
903 new_segment:
904 if (!sk_stream_memory_free(sk))
905 goto wait_for_sndbuf;
906
907 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
908 if (!skb)
909 goto wait_for_memory;
910
911 skb_entail(sk, skb);
912 copy = size_goal;
913 }
914
915 if (copy > size)
916 copy = size;
917
918 i = skb_shinfo(skb)->nr_frags;
919 can_coalesce = skb_can_coalesce(skb, i, page, offset);
920 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
921 tcp_mark_push(tp, skb);
922 goto new_segment;
923 }
924 if (!sk_wmem_schedule(sk, copy))
925 goto wait_for_memory;
926
927 if (can_coalesce) {
928 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
929 } else {
930 get_page(page);
931 skb_fill_page_desc(skb, i, page, offset, copy);
932 }
933 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
934
935 skb->len += copy;
936 skb->data_len += copy;
937 skb->truesize += copy;
938 sk->sk_wmem_queued += copy;
939 sk_mem_charge(sk, copy);
940 skb->ip_summed = CHECKSUM_PARTIAL;
941 tp->write_seq += copy;
942 TCP_SKB_CB(skb)->end_seq += copy;
943 tcp_skb_pcount_set(skb, 0);
944
945 if (!copied)
946 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
947
948 copied += copy;
949 offset += copy;
950 if (!(size -= copy)) {
951 tcp_tx_timestamp(sk, skb);
952 goto out;
953 }
954
955 if (skb->len < size_goal || (flags & MSG_OOB))
956 continue;
957
958 if (forced_push(tp)) {
959 tcp_mark_push(tp, skb);
960 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
961 } else if (skb == tcp_send_head(sk))
962 tcp_push_one(sk, mss_now);
963 continue;
964
965 wait_for_sndbuf:
966 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
967 wait_for_memory:
968 tcp_push(sk, flags & ~MSG_MORE, mss_now,
969 TCP_NAGLE_PUSH, size_goal);
970
971 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
972 goto do_error;
973
974 mss_now = tcp_send_mss(sk, &size_goal, flags);
975 }
976
977 out:
978 if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
979 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
980 return copied;
981
982 do_error:
983 if (copied)
984 goto out;
985 out_err:
986 return sk_stream_error(sk, flags, err);
987 }
988
989 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
990 size_t size, int flags)
991 {
992 ssize_t res;
993
994 if (!(sk->sk_route_caps & NETIF_F_SG) ||
995 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
996 return sock_no_sendpage(sk->sk_socket, page, offset, size,
997 flags);
998
999 lock_sock(sk);
1000 res = do_tcp_sendpages(sk, page, offset, size, flags);
1001 release_sock(sk);
1002 return res;
1003 }
1004 EXPORT_SYMBOL(tcp_sendpage);
1005
1006 static inline int select_size(const struct sock *sk, bool sg)
1007 {
1008 const struct tcp_sock *tp = tcp_sk(sk);
1009 int tmp = tp->mss_cache;
1010
1011 if (sg) {
1012 if (sk_can_gso(sk)) {
1013 /* Small frames wont use a full page:
1014 * Payload will immediately follow tcp header.
1015 */
1016 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
1017 } else {
1018 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
1019
1020 if (tmp >= pgbreak &&
1021 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
1022 tmp = pgbreak;
1023 }
1024 }
1025
1026 return tmp;
1027 }
1028
1029 void tcp_free_fastopen_req(struct tcp_sock *tp)
1030 {
1031 if (tp->fastopen_req != NULL) {
1032 kfree(tp->fastopen_req);
1033 tp->fastopen_req = NULL;
1034 }
1035 }
1036
1037 static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1038 int *copied, size_t size)
1039 {
1040 struct tcp_sock *tp = tcp_sk(sk);
1041 int err, flags;
1042
1043 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
1044 return -EOPNOTSUPP;
1045 if (tp->fastopen_req != NULL)
1046 return -EALREADY; /* Another Fast Open is in progress */
1047
1048 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1049 sk->sk_allocation);
1050 if (unlikely(tp->fastopen_req == NULL))
1051 return -ENOBUFS;
1052 tp->fastopen_req->data = msg;
1053 tp->fastopen_req->size = size;
1054
1055 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1056 err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1057 msg->msg_namelen, flags);
1058 *copied = tp->fastopen_req->copied;
1059 tcp_free_fastopen_req(tp);
1060 return err;
1061 }
1062
1063 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1064 size_t size)
1065 {
1066 struct tcp_sock *tp = tcp_sk(sk);
1067 struct sk_buff *skb;
1068 int flags, err, copied = 0;
1069 int mss_now = 0, size_goal, copied_syn = 0;
1070 bool sg;
1071 long timeo;
1072
1073 lock_sock(sk);
1074
1075 flags = msg->msg_flags;
1076 if (flags & MSG_FASTOPEN) {
1077 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1078 if (err == -EINPROGRESS && copied_syn > 0)
1079 goto out;
1080 else if (err)
1081 goto out_err;
1082 }
1083
1084 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1085
1086 /* Wait for a connection to finish. One exception is TCP Fast Open
1087 * (passive side) where data is allowed to be sent before a connection
1088 * is fully established.
1089 */
1090 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1091 !tcp_passive_fastopen(sk)) {
1092 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1093 goto do_error;
1094 }
1095
1096 if (unlikely(tp->repair)) {
1097 if (tp->repair_queue == TCP_RECV_QUEUE) {
1098 copied = tcp_send_rcvq(sk, msg, size);
1099 goto out_nopush;
1100 }
1101
1102 err = -EINVAL;
1103 if (tp->repair_queue == TCP_NO_QUEUE)
1104 goto out_err;
1105
1106 /* 'common' sending to sendq */
1107 }
1108
1109 /* This should be in poll */
1110 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1111
1112 mss_now = tcp_send_mss(sk, &size_goal, flags);
1113
1114 /* Ok commence sending. */
1115 copied = 0;
1116
1117 err = -EPIPE;
1118 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1119 goto out_err;
1120
1121 sg = !!(sk->sk_route_caps & NETIF_F_SG);
1122
1123 while (iov_iter_count(&msg->msg_iter)) {
1124 int copy = 0;
1125 int max = size_goal;
1126
1127 skb = tcp_write_queue_tail(sk);
1128 if (tcp_send_head(sk)) {
1129 if (skb->ip_summed == CHECKSUM_NONE)
1130 max = mss_now;
1131 copy = max - skb->len;
1132 }
1133
1134 if (copy <= 0) {
1135 new_segment:
1136 /* Allocate new segment. If the interface is SG,
1137 * allocate skb fitting to single page.
1138 */
1139 if (!sk_stream_memory_free(sk))
1140 goto wait_for_sndbuf;
1141
1142 skb = sk_stream_alloc_skb(sk,
1143 select_size(sk, sg),
1144 sk->sk_allocation);
1145 if (!skb)
1146 goto wait_for_memory;
1147
1148 /*
1149 * Check whether we can use HW checksum.
1150 */
1151 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1152 skb->ip_summed = CHECKSUM_PARTIAL;
1153
1154 skb_entail(sk, skb);
1155 copy = size_goal;
1156 max = size_goal;
1157
1158 /* All packets are restored as if they have
1159 * already been sent. skb_mstamp isn't set to
1160 * avoid wrong rtt estimation.
1161 */
1162 if (tp->repair)
1163 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
1164 }
1165
1166 /* Try to append data to the end of skb. */
1167 if (copy > iov_iter_count(&msg->msg_iter))
1168 copy = iov_iter_count(&msg->msg_iter);
1169
1170 /* Where to copy to? */
1171 if (skb_availroom(skb) > 0) {
1172 /* We have some space in skb head. Superb! */
1173 copy = min_t(int, copy, skb_availroom(skb));
1174 err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);
1175 if (err)
1176 goto do_fault;
1177 } else {
1178 bool merge = true;
1179 int i = skb_shinfo(skb)->nr_frags;
1180 struct page_frag *pfrag = sk_page_frag(sk);
1181
1182 if (!sk_page_frag_refill(sk, pfrag))
1183 goto wait_for_memory;
1184
1185 if (!skb_can_coalesce(skb, i, pfrag->page,
1186 pfrag->offset)) {
1187 if (i == MAX_SKB_FRAGS || !sg) {
1188 tcp_mark_push(tp, skb);
1189 goto new_segment;
1190 }
1191 merge = false;
1192 }
1193
1194 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1195
1196 if (!sk_wmem_schedule(sk, copy))
1197 goto wait_for_memory;
1198
1199 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
1200 pfrag->page,
1201 pfrag->offset,
1202 copy);
1203 if (err)
1204 goto do_error;
1205
1206 /* Update the skb. */
1207 if (merge) {
1208 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1209 } else {
1210 skb_fill_page_desc(skb, i, pfrag->page,
1211 pfrag->offset, copy);
1212 get_page(pfrag->page);
1213 }
1214 pfrag->offset += copy;
1215 }
1216
1217 if (!copied)
1218 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1219
1220 tp->write_seq += copy;
1221 TCP_SKB_CB(skb)->end_seq += copy;
1222 tcp_skb_pcount_set(skb, 0);
1223
1224 copied += copy;
1225 if (!iov_iter_count(&msg->msg_iter)) {
1226 tcp_tx_timestamp(sk, skb);
1227 goto out;
1228 }
1229
1230 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1231 continue;
1232
1233 if (forced_push(tp)) {
1234 tcp_mark_push(tp, skb);
1235 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1236 } else if (skb == tcp_send_head(sk))
1237 tcp_push_one(sk, mss_now);
1238 continue;
1239
1240 wait_for_sndbuf:
1241 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1242 wait_for_memory:
1243 if (copied)
1244 tcp_push(sk, flags & ~MSG_MORE, mss_now,
1245 TCP_NAGLE_PUSH, size_goal);
1246
1247 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1248 goto do_error;
1249
1250 mss_now = tcp_send_mss(sk, &size_goal, flags);
1251 }
1252
1253 out:
1254 if (copied)
1255 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1256 out_nopush:
1257 release_sock(sk);
1258 return copied + copied_syn;
1259
1260 do_fault:
1261 if (!skb->len) {
1262 tcp_unlink_write_queue(skb, sk);
1263 /* It is the one place in all of TCP, except connection
1264 * reset, where we can be unlinking the send_head.
1265 */
1266 tcp_check_send_head(sk, skb);
1267 sk_wmem_free_skb(sk, skb);
1268 }
1269
1270 do_error:
1271 if (copied + copied_syn)
1272 goto out;
1273 out_err:
1274 err = sk_stream_error(sk, flags, err);
1275 release_sock(sk);
1276 return err;
1277 }
1278 EXPORT_SYMBOL(tcp_sendmsg);
1279
1280 /*
1281 * Handle reading urgent data. BSD has very simple semantics for
1282 * this, no blocking and very strange errors 8)
1283 */
1284
1285 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1286 {
1287 struct tcp_sock *tp = tcp_sk(sk);
1288
1289 /* No URG data to read. */
1290 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1291 tp->urg_data == TCP_URG_READ)
1292 return -EINVAL; /* Yes this is right ! */
1293
1294 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1295 return -ENOTCONN;
1296
1297 if (tp->urg_data & TCP_URG_VALID) {
1298 int err = 0;
1299 char c = tp->urg_data;
1300
1301 if (!(flags & MSG_PEEK))
1302 tp->urg_data = TCP_URG_READ;
1303
1304 /* Read urgent data. */
1305 msg->msg_flags |= MSG_OOB;
1306
1307 if (len > 0) {
1308 if (!(flags & MSG_TRUNC))
1309 err = memcpy_to_msg(msg, &c, 1);
1310 len = 1;
1311 } else
1312 msg->msg_flags |= MSG_TRUNC;
1313
1314 return err ? -EFAULT : len;
1315 }
1316
1317 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1318 return 0;
1319
1320 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1321 * the available implementations agree in this case:
1322 * this call should never block, independent of the
1323 * blocking state of the socket.
1324 * Mike <pall@rz.uni-karlsruhe.de>
1325 */
1326 return -EAGAIN;
1327 }
1328
1329 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1330 {
1331 struct sk_buff *skb;
1332 int copied = 0, err = 0;
1333
1334 /* XXX -- need to support SO_PEEK_OFF */
1335
1336 skb_queue_walk(&sk->sk_write_queue, skb) {
1337 err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
1338 if (err)
1339 break;
1340
1341 copied += skb->len;
1342 }
1343
1344 return err ?: copied;
1345 }
1346
1347 /* Clean up the receive buffer for full frames taken by the user,
1348 * then send an ACK if necessary. COPIED is the number of bytes
1349 * tcp_recvmsg has given to the user so far, it speeds up the
1350 * calculation of whether or not we must ACK for the sake of
1351 * a window update.
1352 */
1353 static void tcp_cleanup_rbuf(struct sock *sk, int copied)
1354 {
1355 struct tcp_sock *tp = tcp_sk(sk);
1356 bool time_to_ack = false;
1357
1358 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1359
1360 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1361 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1362 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1363
1364 if (inet_csk_ack_scheduled(sk)) {
1365 const struct inet_connection_sock *icsk = inet_csk(sk);
1366 /* Delayed ACKs frequently hit locked sockets during bulk
1367 * receive. */
1368 if (icsk->icsk_ack.blocked ||
1369 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1370 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1371 /*
1372 * If this read emptied read buffer, we send ACK, if
1373 * connection is not bidirectional, user drained
1374 * receive buffer and there was a small segment
1375 * in queue.
1376 */
1377 (copied > 0 &&
1378 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1379 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1380 !icsk->icsk_ack.pingpong)) &&
1381 !atomic_read(&sk->sk_rmem_alloc)))
1382 time_to_ack = true;
1383 }
1384
1385 /* We send an ACK if we can now advertise a non-zero window
1386 * which has been raised "significantly".
1387 *
1388 * Even if window raised up to infinity, do not send window open ACK
1389 * in states, where we will not receive more. It is useless.
1390 */
1391 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1392 __u32 rcv_window_now = tcp_receive_window(tp);
1393
1394 /* Optimize, __tcp_select_window() is not cheap. */
1395 if (2*rcv_window_now <= tp->window_clamp) {
1396 __u32 new_window = __tcp_select_window(sk);
1397
1398 /* Send ACK now, if this read freed lots of space
1399 * in our buffer. Certainly, new_window is new window.
1400 * We can advertise it now, if it is not less than current one.
1401 * "Lots" means "at least twice" here.
1402 */
1403 if (new_window && new_window >= 2 * rcv_window_now)
1404 time_to_ack = true;
1405 }
1406 }
1407 if (time_to_ack)
1408 tcp_send_ack(sk);
1409 }
1410
1411 static void tcp_prequeue_process(struct sock *sk)
1412 {
1413 struct sk_buff *skb;
1414 struct tcp_sock *tp = tcp_sk(sk);
1415
1416 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1417
1418 /* RX process wants to run with disabled BHs, though it is not
1419 * necessary */
1420 local_bh_disable();
1421 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1422 sk_backlog_rcv(sk, skb);
1423 local_bh_enable();
1424
1425 /* Clear memory counter. */
1426 tp->ucopy.memory = 0;
1427 }
1428
1429 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1430 {
1431 struct sk_buff *skb;
1432 u32 offset;
1433
1434 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1435 offset = seq - TCP_SKB_CB(skb)->seq;
1436 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
1437 offset--;
1438 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
1439 *off = offset;
1440 return skb;
1441 }
1442 /* This looks weird, but this can happen if TCP collapsing
1443 * splitted a fat GRO packet, while we released socket lock
1444 * in skb_splice_bits()
1445 */
1446 sk_eat_skb(sk, skb);
1447 }
1448 return NULL;
1449 }
1450
1451 /*
1452 * This routine provides an alternative to tcp_recvmsg() for routines
1453 * that would like to handle copying from skbuffs directly in 'sendfile'
1454 * fashion.
1455 * Note:
1456 * - It is assumed that the socket was locked by the caller.
1457 * - The routine does not block.
1458 * - At present, there is no support for reading OOB data
1459 * or for 'peeking' the socket using this routine
1460 * (although both would be easy to implement).
1461 */
1462 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1463 sk_read_actor_t recv_actor)
1464 {
1465 struct sk_buff *skb;
1466 struct tcp_sock *tp = tcp_sk(sk);
1467 u32 seq = tp->copied_seq;
1468 u32 offset;
1469 int copied = 0;
1470
1471 if (sk->sk_state == TCP_LISTEN)
1472 return -ENOTCONN;
1473 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1474 if (offset < skb->len) {
1475 int used;
1476 size_t len;
1477
1478 len = skb->len - offset;
1479 /* Stop reading if we hit a patch of urgent data */
1480 if (tp->urg_data) {
1481 u32 urg_offset = tp->urg_seq - seq;
1482 if (urg_offset < len)
1483 len = urg_offset;
1484 if (!len)
1485 break;
1486 }
1487 used = recv_actor(desc, skb, offset, len);
1488 if (used <= 0) {
1489 if (!copied)
1490 copied = used;
1491 break;
1492 } else if (used <= len) {
1493 seq += used;
1494 copied += used;
1495 offset += used;
1496 }
1497 /* If recv_actor drops the lock (e.g. TCP splice
1498 * receive) the skb pointer might be invalid when
1499 * getting here: tcp_collapse might have deleted it
1500 * while aggregating skbs from the socket queue.
1501 */
1502 skb = tcp_recv_skb(sk, seq - 1, &offset);
1503 if (!skb)
1504 break;
1505 /* TCP coalescing might have appended data to the skb.
1506 * Try to splice more frags
1507 */
1508 if (offset + 1 != skb->len)
1509 continue;
1510 }
1511 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1512 sk_eat_skb(sk, skb);
1513 ++seq;
1514 break;
1515 }
1516 sk_eat_skb(sk, skb);
1517 if (!desc->count)
1518 break;
1519 tp->copied_seq = seq;
1520 }
1521 tp->copied_seq = seq;
1522
1523 tcp_rcv_space_adjust(sk);
1524
1525 /* Clean up data we have read: This will do ACK frames. */
1526 if (copied > 0) {
1527 tcp_recv_skb(sk, seq, &offset);
1528 tcp_cleanup_rbuf(sk, copied);
1529 }
1530 return copied;
1531 }
1532 EXPORT_SYMBOL(tcp_read_sock);
1533
1534 /*
1535 * This routine copies from a sock struct into the user buffer.
1536 *
1537 * Technical note: in 2.3 we work on _locked_ socket, so that
1538 * tricks with *seq access order and skb->users are not required.
1539 * Probably, code can be easily improved even more.
1540 */
1541
1542 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1543 size_t len, int nonblock, int flags, int *addr_len)
1544 {
1545 struct tcp_sock *tp = tcp_sk(sk);
1546 int copied = 0;
1547 u32 peek_seq;
1548 u32 *seq;
1549 unsigned long used;
1550 int err;
1551 int target; /* Read at least this many bytes */
1552 long timeo;
1553 struct task_struct *user_recv = NULL;
1554 struct sk_buff *skb;
1555 u32 urg_hole = 0;
1556
1557 if (unlikely(flags & MSG_ERRQUEUE))
1558 return inet_recv_error(sk, msg, len, addr_len);
1559
1560 if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
1561 (sk->sk_state == TCP_ESTABLISHED))
1562 sk_busy_loop(sk, nonblock);
1563
1564 lock_sock(sk);
1565
1566 err = -ENOTCONN;
1567 if (sk->sk_state == TCP_LISTEN)
1568 goto out;
1569
1570 timeo = sock_rcvtimeo(sk, nonblock);
1571
1572 /* Urgent data needs to be handled specially. */
1573 if (flags & MSG_OOB)
1574 goto recv_urg;
1575
1576 if (unlikely(tp->repair)) {
1577 err = -EPERM;
1578 if (!(flags & MSG_PEEK))
1579 goto out;
1580
1581 if (tp->repair_queue == TCP_SEND_QUEUE)
1582 goto recv_sndq;
1583
1584 err = -EINVAL;
1585 if (tp->repair_queue == TCP_NO_QUEUE)
1586 goto out;
1587
1588 /* 'common' recv queue MSG_PEEK-ing */
1589 }
1590
1591 seq = &tp->copied_seq;
1592 if (flags & MSG_PEEK) {
1593 peek_seq = tp->copied_seq;
1594 seq = &peek_seq;
1595 }
1596
1597 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1598
1599 do {
1600 u32 offset;
1601
1602 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1603 if (tp->urg_data && tp->urg_seq == *seq) {
1604 if (copied)
1605 break;
1606 if (signal_pending(current)) {
1607 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1608 break;
1609 }
1610 }
1611
1612 /* Next get a buffer. */
1613
1614 skb_queue_walk(&sk->sk_receive_queue, skb) {
1615 /* Now that we have two receive queues this
1616 * shouldn't happen.
1617 */
1618 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1619 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1620 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1621 flags))
1622 break;
1623
1624 offset = *seq - TCP_SKB_CB(skb)->seq;
1625 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
1626 offset--;
1627 if (offset < skb->len)
1628 goto found_ok_skb;
1629 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1630 goto found_fin_ok;
1631 WARN(!(flags & MSG_PEEK),
1632 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1633 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1634 }
1635
1636 /* Well, if we have backlog, try to process it now yet. */
1637
1638 if (copied >= target && !sk->sk_backlog.tail)
1639 break;
1640
1641 if (copied) {
1642 if (sk->sk_err ||
1643 sk->sk_state == TCP_CLOSE ||
1644 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1645 !timeo ||
1646 signal_pending(current))
1647 break;
1648 } else {
1649 if (sock_flag(sk, SOCK_DONE))
1650 break;
1651
1652 if (sk->sk_err) {
1653 copied = sock_error(sk);
1654 break;
1655 }
1656
1657 if (sk->sk_shutdown & RCV_SHUTDOWN)
1658 break;
1659
1660 if (sk->sk_state == TCP_CLOSE) {
1661 if (!sock_flag(sk, SOCK_DONE)) {
1662 /* This occurs when user tries to read
1663 * from never connected socket.
1664 */
1665 copied = -ENOTCONN;
1666 break;
1667 }
1668 break;
1669 }
1670
1671 if (!timeo) {
1672 copied = -EAGAIN;
1673 break;
1674 }
1675
1676 if (signal_pending(current)) {
1677 copied = sock_intr_errno(timeo);
1678 break;
1679 }
1680 }
1681
1682 tcp_cleanup_rbuf(sk, copied);
1683
1684 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1685 /* Install new reader */
1686 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1687 user_recv = current;
1688 tp->ucopy.task = user_recv;
1689 tp->ucopy.msg = msg;
1690 }
1691
1692 tp->ucopy.len = len;
1693
1694 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1695 !(flags & (MSG_PEEK | MSG_TRUNC)));
1696
1697 /* Ugly... If prequeue is not empty, we have to
1698 * process it before releasing socket, otherwise
1699 * order will be broken at second iteration.
1700 * More elegant solution is required!!!
1701 *
1702 * Look: we have the following (pseudo)queues:
1703 *
1704 * 1. packets in flight
1705 * 2. backlog
1706 * 3. prequeue
1707 * 4. receive_queue
1708 *
1709 * Each queue can be processed only if the next ones
1710 * are empty. At this point we have empty receive_queue.
1711 * But prequeue _can_ be not empty after 2nd iteration,
1712 * when we jumped to start of loop because backlog
1713 * processing added something to receive_queue.
1714 * We cannot release_sock(), because backlog contains
1715 * packets arrived _after_ prequeued ones.
1716 *
1717 * Shortly, algorithm is clear --- to process all
1718 * the queues in order. We could make it more directly,
1719 * requeueing packets from backlog to prequeue, if
1720 * is not empty. It is more elegant, but eats cycles,
1721 * unfortunately.
1722 */
1723 if (!skb_queue_empty(&tp->ucopy.prequeue))
1724 goto do_prequeue;
1725
1726 /* __ Set realtime policy in scheduler __ */
1727 }
1728
1729 if (copied >= target) {
1730 /* Do not sleep, just process backlog. */
1731 release_sock(sk);
1732 lock_sock(sk);
1733 } else
1734 sk_wait_data(sk, &timeo);
1735
1736 if (user_recv) {
1737 int chunk;
1738
1739 /* __ Restore normal policy in scheduler __ */
1740
1741 if ((chunk = len - tp->ucopy.len) != 0) {
1742 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1743 len -= chunk;
1744 copied += chunk;
1745 }
1746
1747 if (tp->rcv_nxt == tp->copied_seq &&
1748 !skb_queue_empty(&tp->ucopy.prequeue)) {
1749 do_prequeue:
1750 tcp_prequeue_process(sk);
1751
1752 if ((chunk = len - tp->ucopy.len) != 0) {
1753 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1754 len -= chunk;
1755 copied += chunk;
1756 }
1757 }
1758 }
1759 if ((flags & MSG_PEEK) &&
1760 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1761 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
1762 current->comm,
1763 task_pid_nr(current));
1764 peek_seq = tp->copied_seq;
1765 }
1766 continue;
1767
1768 found_ok_skb:
1769 /* Ok so how much can we use? */
1770 used = skb->len - offset;
1771 if (len < used)
1772 used = len;
1773
1774 /* Do we have urgent data here? */
1775 if (tp->urg_data) {
1776 u32 urg_offset = tp->urg_seq - *seq;
1777 if (urg_offset < used) {
1778 if (!urg_offset) {
1779 if (!sock_flag(sk, SOCK_URGINLINE)) {
1780 ++*seq;
1781 urg_hole++;
1782 offset++;
1783 used--;
1784 if (!used)
1785 goto skip_copy;
1786 }
1787 } else
1788 used = urg_offset;
1789 }
1790 }
1791
1792 if (!(flags & MSG_TRUNC)) {
1793 err = skb_copy_datagram_msg(skb, offset, msg, used);
1794 if (err) {
1795 /* Exception. Bailout! */
1796 if (!copied)
1797 copied = -EFAULT;
1798 break;
1799 }
1800 }
1801
1802 *seq += used;
1803 copied += used;
1804 len -= used;
1805
1806 tcp_rcv_space_adjust(sk);
1807
1808 skip_copy:
1809 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1810 tp->urg_data = 0;
1811 tcp_fast_path_check(sk);
1812 }
1813 if (used + offset < skb->len)
1814 continue;
1815
1816 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1817 goto found_fin_ok;
1818 if (!(flags & MSG_PEEK))
1819 sk_eat_skb(sk, skb);
1820 continue;
1821
1822 found_fin_ok:
1823 /* Process the FIN. */
1824 ++*seq;
1825 if (!(flags & MSG_PEEK))
1826 sk_eat_skb(sk, skb);
1827 break;
1828 } while (len > 0);
1829
1830 if (user_recv) {
1831 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1832 int chunk;
1833
1834 tp->ucopy.len = copied > 0 ? len : 0;
1835
1836 tcp_prequeue_process(sk);
1837
1838 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1839 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1840 len -= chunk;
1841 copied += chunk;
1842 }
1843 }
1844
1845 tp->ucopy.task = NULL;
1846 tp->ucopy.len = 0;
1847 }
1848
1849 /* According to UNIX98, msg_name/msg_namelen are ignored
1850 * on connected socket. I was just happy when found this 8) --ANK
1851 */
1852
1853 /* Clean up data we have read: This will do ACK frames. */
1854 tcp_cleanup_rbuf(sk, copied);
1855
1856 release_sock(sk);
1857 return copied;
1858
1859 out:
1860 release_sock(sk);
1861 return err;
1862
1863 recv_urg:
1864 err = tcp_recv_urg(sk, msg, len, flags);
1865 goto out;
1866
1867 recv_sndq:
1868 err = tcp_peek_sndq(sk, msg, len);
1869 goto out;
1870 }
1871 EXPORT_SYMBOL(tcp_recvmsg);
1872
1873 void tcp_set_state(struct sock *sk, int state)
1874 {
1875 int oldstate = sk->sk_state;
1876
1877 switch (state) {
1878 case TCP_ESTABLISHED:
1879 if (oldstate != TCP_ESTABLISHED)
1880 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1881 break;
1882
1883 case TCP_CLOSE:
1884 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1885 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1886
1887 sk->sk_prot->unhash(sk);
1888 if (inet_csk(sk)->icsk_bind_hash &&
1889 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1890 inet_put_port(sk);
1891 /* fall through */
1892 default:
1893 if (oldstate == TCP_ESTABLISHED)
1894 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1895 }
1896
1897 /* Change state AFTER socket is unhashed to avoid closed
1898 * socket sitting in hash tables.
1899 */
1900 sk->sk_state = state;
1901
1902 #ifdef STATE_TRACE
1903 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1904 #endif
1905 }
1906 EXPORT_SYMBOL_GPL(tcp_set_state);
1907
1908 /*
1909 * State processing on a close. This implements the state shift for
1910 * sending our FIN frame. Note that we only send a FIN for some
1911 * states. A shutdown() may have already sent the FIN, or we may be
1912 * closed.
1913 */
1914
1915 static const unsigned char new_state[16] = {
1916 /* current state: new state: action: */
1917 /* (Invalid) */ TCP_CLOSE,
1918 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1919 /* TCP_SYN_SENT */ TCP_CLOSE,
1920 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1921 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1922 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1923 /* TCP_TIME_WAIT */ TCP_CLOSE,
1924 /* TCP_CLOSE */ TCP_CLOSE,
1925 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1926 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1927 /* TCP_LISTEN */ TCP_CLOSE,
1928 /* TCP_CLOSING */ TCP_CLOSING,
1929 };
1930
1931 static int tcp_close_state(struct sock *sk)
1932 {
1933 int next = (int)new_state[sk->sk_state];
1934 int ns = next & TCP_STATE_MASK;
1935
1936 tcp_set_state(sk, ns);
1937
1938 return next & TCP_ACTION_FIN;
1939 }
1940
1941 /*
1942 * Shutdown the sending side of a connection. Much like close except
1943 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1944 */
1945
1946 void tcp_shutdown(struct sock *sk, int how)
1947 {
1948 /* We need to grab some memory, and put together a FIN,
1949 * and then put it into the queue to be sent.
1950 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1951 */
1952 if (!(how & SEND_SHUTDOWN))
1953 return;
1954
1955 /* If we've already sent a FIN, or it's a closed state, skip this. */
1956 if ((1 << sk->sk_state) &
1957 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1958 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1959 /* Clear out any half completed packets. FIN if needed. */
1960 if (tcp_close_state(sk))
1961 tcp_send_fin(sk);
1962 }
1963 }
1964 EXPORT_SYMBOL(tcp_shutdown);
1965
1966 bool tcp_check_oom(struct sock *sk, int shift)
1967 {
1968 bool too_many_orphans, out_of_socket_memory;
1969
1970 too_many_orphans = tcp_too_many_orphans(sk, shift);
1971 out_of_socket_memory = tcp_out_of_memory(sk);
1972
1973 if (too_many_orphans)
1974 net_info_ratelimited("too many orphaned sockets\n");
1975 if (out_of_socket_memory)
1976 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
1977 return too_many_orphans || out_of_socket_memory;
1978 }
1979
1980 void tcp_close(struct sock *sk, long timeout)
1981 {
1982 struct sk_buff *skb;
1983 int data_was_unread = 0;
1984 int state;
1985
1986 lock_sock(sk);
1987 sk->sk_shutdown = SHUTDOWN_MASK;
1988
1989 if (sk->sk_state == TCP_LISTEN) {
1990 tcp_set_state(sk, TCP_CLOSE);
1991
1992 /* Special case. */
1993 inet_csk_listen_stop(sk);
1994
1995 goto adjudge_to_death;
1996 }
1997
1998 /* We need to flush the recv. buffs. We do this only on the
1999 * descriptor close, not protocol-sourced closes, because the
2000 * reader process may not have drained the data yet!
2001 */
2002 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2003 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
2004
2005 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2006 len--;
2007 data_was_unread += len;
2008 __kfree_skb(skb);
2009 }
2010
2011 sk_mem_reclaim(sk);
2012
2013 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2014 if (sk->sk_state == TCP_CLOSE)
2015 goto adjudge_to_death;
2016
2017 /* As outlined in RFC 2525, section 2.17, we send a RST here because
2018 * data was lost. To witness the awful effects of the old behavior of
2019 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2020 * GET in an FTP client, suspend the process, wait for the client to
2021 * advertise a zero window, then kill -9 the FTP client, wheee...
2022 * Note: timeout is always zero in such a case.
2023 */
2024 if (unlikely(tcp_sk(sk)->repair)) {
2025 sk->sk_prot->disconnect(sk, 0);
2026 } else if (data_was_unread) {
2027 /* Unread data was tossed, zap the connection. */
2028 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2029 tcp_set_state(sk, TCP_CLOSE);
2030 tcp_send_active_reset(sk, sk->sk_allocation);
2031 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2032 /* Check zero linger _after_ checking for unread data. */
2033 sk->sk_prot->disconnect(sk, 0);
2034 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2035 } else if (tcp_close_state(sk)) {
2036 /* We FIN if the application ate all the data before
2037 * zapping the connection.
2038 */
2039
2040 /* RED-PEN. Formally speaking, we have broken TCP state
2041 * machine. State transitions:
2042 *
2043 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2044 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2045 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2046 *
2047 * are legal only when FIN has been sent (i.e. in window),
2048 * rather than queued out of window. Purists blame.
2049 *
2050 * F.e. "RFC state" is ESTABLISHED,
2051 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2052 *
2053 * The visible declinations are that sometimes
2054 * we enter time-wait state, when it is not required really
2055 * (harmless), do not send active resets, when they are
2056 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2057 * they look as CLOSING or LAST_ACK for Linux)
2058 * Probably, I missed some more holelets.
2059 * --ANK
2060 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2061 * in a single packet! (May consider it later but will
2062 * probably need API support or TCP_CORK SYN-ACK until
2063 * data is written and socket is closed.)
2064 */
2065 tcp_send_fin(sk);
2066 }
2067
2068 sk_stream_wait_close(sk, timeout);
2069
2070 adjudge_to_death:
2071 state = sk->sk_state;
2072 sock_hold(sk);
2073 sock_orphan(sk);
2074
2075 /* It is the last release_sock in its life. It will remove backlog. */
2076 release_sock(sk);
2077
2078
2079 /* Now socket is owned by kernel and we acquire BH lock
2080 to finish close. No need to check for user refs.
2081 */
2082 local_bh_disable();
2083 bh_lock_sock(sk);
2084 WARN_ON(sock_owned_by_user(sk));
2085
2086 percpu_counter_inc(sk->sk_prot->orphan_count);
2087
2088 /* Have we already been destroyed by a softirq or backlog? */
2089 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2090 goto out;
2091
2092 /* This is a (useful) BSD violating of the RFC. There is a
2093 * problem with TCP as specified in that the other end could
2094 * keep a socket open forever with no application left this end.
2095 * We use a 1 minute timeout (about the same as BSD) then kill
2096 * our end. If they send after that then tough - BUT: long enough
2097 * that we won't make the old 4*rto = almost no time - whoops
2098 * reset mistake.
2099 *
2100 * Nope, it was not mistake. It is really desired behaviour
2101 * f.e. on http servers, when such sockets are useless, but
2102 * consume significant resources. Let's do it with special
2103 * linger2 option. --ANK
2104 */
2105
2106 if (sk->sk_state == TCP_FIN_WAIT2) {
2107 struct tcp_sock *tp = tcp_sk(sk);
2108 if (tp->linger2 < 0) {
2109 tcp_set_state(sk, TCP_CLOSE);
2110 tcp_send_active_reset(sk, GFP_ATOMIC);
2111 NET_INC_STATS_BH(sock_net(sk),
2112 LINUX_MIB_TCPABORTONLINGER);
2113 } else {
2114 const int tmo = tcp_fin_time(sk);
2115
2116 if (tmo > TCP_TIMEWAIT_LEN) {
2117 inet_csk_reset_keepalive_timer(sk,
2118 tmo - TCP_TIMEWAIT_LEN);
2119 } else {
2120 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2121 goto out;
2122 }
2123 }
2124 }
2125 if (sk->sk_state != TCP_CLOSE) {
2126 sk_mem_reclaim(sk);
2127 if (tcp_check_oom(sk, 0)) {
2128 tcp_set_state(sk, TCP_CLOSE);
2129 tcp_send_active_reset(sk, GFP_ATOMIC);
2130 NET_INC_STATS_BH(sock_net(sk),
2131 LINUX_MIB_TCPABORTONMEMORY);
2132 }
2133 }
2134
2135 if (sk->sk_state == TCP_CLOSE) {
2136 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2137 /* We could get here with a non-NULL req if the socket is
2138 * aborted (e.g., closed with unread data) before 3WHS
2139 * finishes.
2140 */
2141 if (req != NULL)
2142 reqsk_fastopen_remove(sk, req, false);
2143 inet_csk_destroy_sock(sk);
2144 }
2145 /* Otherwise, socket is reprieved until protocol close. */
2146
2147 out:
2148 bh_unlock_sock(sk);
2149 local_bh_enable();
2150 sock_put(sk);
2151 }
2152 EXPORT_SYMBOL(tcp_close);
2153
2154 /* These states need RST on ABORT according to RFC793 */
2155
2156 static inline bool tcp_need_reset(int state)
2157 {
2158 return (1 << state) &
2159 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2160 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2161 }
2162
2163 int tcp_disconnect(struct sock *sk, int flags)
2164 {
2165 struct inet_sock *inet = inet_sk(sk);
2166 struct inet_connection_sock *icsk = inet_csk(sk);
2167 struct tcp_sock *tp = tcp_sk(sk);
2168 int err = 0;
2169 int old_state = sk->sk_state;
2170
2171 if (old_state != TCP_CLOSE)
2172 tcp_set_state(sk, TCP_CLOSE);
2173
2174 /* ABORT function of RFC793 */
2175 if (old_state == TCP_LISTEN) {
2176 inet_csk_listen_stop(sk);
2177 } else if (unlikely(tp->repair)) {
2178 sk->sk_err = ECONNABORTED;
2179 } else if (tcp_need_reset(old_state) ||
2180 (tp->snd_nxt != tp->write_seq &&
2181 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2182 /* The last check adjusts for discrepancy of Linux wrt. RFC
2183 * states
2184 */
2185 tcp_send_active_reset(sk, gfp_any());
2186 sk->sk_err = ECONNRESET;
2187 } else if (old_state == TCP_SYN_SENT)
2188 sk->sk_err = ECONNRESET;
2189
2190 tcp_clear_xmit_timers(sk);
2191 __skb_queue_purge(&sk->sk_receive_queue);
2192 tcp_write_queue_purge(sk);
2193 __skb_queue_purge(&tp->out_of_order_queue);
2194
2195 inet->inet_dport = 0;
2196
2197 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2198 inet_reset_saddr(sk);
2199
2200 sk->sk_shutdown = 0;
2201 sock_reset_flag(sk, SOCK_DONE);
2202 tp->srtt_us = 0;
2203 if ((tp->write_seq += tp->max_window + 2) == 0)
2204 tp->write_seq = 1;
2205 icsk->icsk_backoff = 0;
2206 tp->snd_cwnd = 2;
2207 icsk->icsk_probes_out = 0;
2208 tp->packets_out = 0;
2209 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2210 tp->snd_cwnd_cnt = 0;
2211 tp->window_clamp = 0;
2212 tcp_set_ca_state(sk, TCP_CA_Open);
2213 tcp_clear_retrans(tp);
2214 inet_csk_delack_init(sk);
2215 tcp_init_send_head(sk);
2216 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2217 __sk_dst_reset(sk);
2218
2219 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2220
2221 sk->sk_error_report(sk);
2222 return err;
2223 }
2224 EXPORT_SYMBOL(tcp_disconnect);
2225
2226 void tcp_sock_destruct(struct sock *sk)
2227 {
2228 inet_sock_destruct(sk);
2229
2230 kfree(inet_csk(sk)->icsk_accept_queue.fastopenq);
2231 }
2232
2233 static inline bool tcp_can_repair_sock(const struct sock *sk)
2234 {
2235 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
2236 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
2237 }
2238
2239 static int tcp_repair_options_est(struct tcp_sock *tp,
2240 struct tcp_repair_opt __user *optbuf, unsigned int len)
2241 {
2242 struct tcp_repair_opt opt;
2243
2244 while (len >= sizeof(opt)) {
2245 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2246 return -EFAULT;
2247
2248 optbuf++;
2249 len -= sizeof(opt);
2250
2251 switch (opt.opt_code) {
2252 case TCPOPT_MSS:
2253 tp->rx_opt.mss_clamp = opt.opt_val;
2254 break;
2255 case TCPOPT_WINDOW:
2256 {
2257 u16 snd_wscale = opt.opt_val & 0xFFFF;
2258 u16 rcv_wscale = opt.opt_val >> 16;
2259
2260 if (snd_wscale > 14 || rcv_wscale > 14)
2261 return -EFBIG;
2262
2263 tp->rx_opt.snd_wscale = snd_wscale;
2264 tp->rx_opt.rcv_wscale = rcv_wscale;
2265 tp->rx_opt.wscale_ok = 1;
2266 }
2267 break;
2268 case TCPOPT_SACK_PERM:
2269 if (opt.opt_val != 0)
2270 return -EINVAL;
2271
2272 tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2273 if (sysctl_tcp_fack)
2274 tcp_enable_fack(tp);
2275 break;
2276 case TCPOPT_TIMESTAMP:
2277 if (opt.opt_val != 0)
2278 return -EINVAL;
2279
2280 tp->rx_opt.tstamp_ok = 1;
2281 break;
2282 }
2283 }
2284
2285 return 0;
2286 }
2287
2288 /*
2289 * Socket option code for TCP.
2290 */
2291 static int do_tcp_setsockopt(struct sock *sk, int level,
2292 int optname, char __user *optval, unsigned int optlen)
2293 {
2294 struct tcp_sock *tp = tcp_sk(sk);
2295 struct inet_connection_sock *icsk = inet_csk(sk);
2296 int val;
2297 int err = 0;
2298
2299 /* These are data/string values, all the others are ints */
2300 switch (optname) {
2301 case TCP_CONGESTION: {
2302 char name[TCP_CA_NAME_MAX];
2303
2304 if (optlen < 1)
2305 return -EINVAL;
2306
2307 val = strncpy_from_user(name, optval,
2308 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2309 if (val < 0)
2310 return -EFAULT;
2311 name[val] = 0;
2312
2313 lock_sock(sk);
2314 err = tcp_set_congestion_control(sk, name);
2315 release_sock(sk);
2316 return err;
2317 }
2318 default:
2319 /* fallthru */
2320 break;
2321 }
2322
2323 if (optlen < sizeof(int))
2324 return -EINVAL;
2325
2326 if (get_user(val, (int __user *)optval))
2327 return -EFAULT;
2328
2329 lock_sock(sk);
2330
2331 switch (optname) {
2332 case TCP_MAXSEG:
2333 /* Values greater than interface MTU won't take effect. However
2334 * at the point when this call is done we typically don't yet
2335 * know which interface is going to be used */
2336 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2337 err = -EINVAL;
2338 break;
2339 }
2340 tp->rx_opt.user_mss = val;
2341 break;
2342
2343 case TCP_NODELAY:
2344 if (val) {
2345 /* TCP_NODELAY is weaker than TCP_CORK, so that
2346 * this option on corked socket is remembered, but
2347 * it is not activated until cork is cleared.
2348 *
2349 * However, when TCP_NODELAY is set we make
2350 * an explicit push, which overrides even TCP_CORK
2351 * for currently queued segments.
2352 */
2353 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2354 tcp_push_pending_frames(sk);
2355 } else {
2356 tp->nonagle &= ~TCP_NAGLE_OFF;
2357 }
2358 break;
2359
2360 case TCP_THIN_LINEAR_TIMEOUTS:
2361 if (val < 0 || val > 1)
2362 err = -EINVAL;
2363 else
2364 tp->thin_lto = val;
2365 break;
2366
2367 case TCP_THIN_DUPACK:
2368 if (val < 0 || val > 1)
2369 err = -EINVAL;
2370 else {
2371 tp->thin_dupack = val;
2372 if (tp->thin_dupack)
2373 tcp_disable_early_retrans(tp);
2374 }
2375 break;
2376
2377 case TCP_REPAIR:
2378 if (!tcp_can_repair_sock(sk))
2379 err = -EPERM;
2380 else if (val == 1) {
2381 tp->repair = 1;
2382 sk->sk_reuse = SK_FORCE_REUSE;
2383 tp->repair_queue = TCP_NO_QUEUE;
2384 } else if (val == 0) {
2385 tp->repair = 0;
2386 sk->sk_reuse = SK_NO_REUSE;
2387 tcp_send_window_probe(sk);
2388 } else
2389 err = -EINVAL;
2390
2391 break;
2392
2393 case TCP_REPAIR_QUEUE:
2394 if (!tp->repair)
2395 err = -EPERM;
2396 else if (val < TCP_QUEUES_NR)
2397 tp->repair_queue = val;
2398 else
2399 err = -EINVAL;
2400 break;
2401
2402 case TCP_QUEUE_SEQ:
2403 if (sk->sk_state != TCP_CLOSE)
2404 err = -EPERM;
2405 else if (tp->repair_queue == TCP_SEND_QUEUE)
2406 tp->write_seq = val;
2407 else if (tp->repair_queue == TCP_RECV_QUEUE)
2408 tp->rcv_nxt = val;
2409 else
2410 err = -EINVAL;
2411 break;
2412
2413 case TCP_REPAIR_OPTIONS:
2414 if (!tp->repair)
2415 err = -EINVAL;
2416 else if (sk->sk_state == TCP_ESTABLISHED)
2417 err = tcp_repair_options_est(tp,
2418 (struct tcp_repair_opt __user *)optval,
2419 optlen);
2420 else
2421 err = -EPERM;
2422 break;
2423
2424 case TCP_CORK:
2425 /* When set indicates to always queue non-full frames.
2426 * Later the user clears this option and we transmit
2427 * any pending partial frames in the queue. This is
2428 * meant to be used alongside sendfile() to get properly
2429 * filled frames when the user (for example) must write
2430 * out headers with a write() call first and then use
2431 * sendfile to send out the data parts.
2432 *
2433 * TCP_CORK can be set together with TCP_NODELAY and it is
2434 * stronger than TCP_NODELAY.
2435 */
2436 if (val) {
2437 tp->nonagle |= TCP_NAGLE_CORK;
2438 } else {
2439 tp->nonagle &= ~TCP_NAGLE_CORK;
2440 if (tp->nonagle&TCP_NAGLE_OFF)
2441 tp->nonagle |= TCP_NAGLE_PUSH;
2442 tcp_push_pending_frames(sk);
2443 }
2444 break;
2445
2446 case TCP_KEEPIDLE:
2447 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2448 err = -EINVAL;
2449 else {
2450 tp->keepalive_time = val * HZ;
2451 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2452 !((1 << sk->sk_state) &
2453 (TCPF_CLOSE | TCPF_LISTEN))) {
2454 u32 elapsed = keepalive_time_elapsed(tp);
2455 if (tp->keepalive_time > elapsed)
2456 elapsed = tp->keepalive_time - elapsed;
2457 else
2458 elapsed = 0;
2459 inet_csk_reset_keepalive_timer(sk, elapsed);
2460 }
2461 }
2462 break;
2463 case TCP_KEEPINTVL:
2464 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2465 err = -EINVAL;
2466 else
2467 tp->keepalive_intvl = val * HZ;
2468 break;
2469 case TCP_KEEPCNT:
2470 if (val < 1 || val > MAX_TCP_KEEPCNT)
2471 err = -EINVAL;
2472 else
2473 tp->keepalive_probes = val;
2474 break;
2475 case TCP_SYNCNT:
2476 if (val < 1 || val > MAX_TCP_SYNCNT)
2477 err = -EINVAL;
2478 else
2479 icsk->icsk_syn_retries = val;
2480 break;
2481
2482 case TCP_LINGER2:
2483 if (val < 0)
2484 tp->linger2 = -1;
2485 else if (val > sysctl_tcp_fin_timeout / HZ)
2486 tp->linger2 = 0;
2487 else
2488 tp->linger2 = val * HZ;
2489 break;
2490
2491 case TCP_DEFER_ACCEPT:
2492 /* Translate value in seconds to number of retransmits */
2493 icsk->icsk_accept_queue.rskq_defer_accept =
2494 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2495 TCP_RTO_MAX / HZ);
2496 break;
2497
2498 case TCP_WINDOW_CLAMP:
2499 if (!val) {
2500 if (sk->sk_state != TCP_CLOSE) {
2501 err = -EINVAL;
2502 break;
2503 }
2504 tp->window_clamp = 0;
2505 } else
2506 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2507 SOCK_MIN_RCVBUF / 2 : val;
2508 break;
2509
2510 case TCP_QUICKACK:
2511 if (!val) {
2512 icsk->icsk_ack.pingpong = 1;
2513 } else {
2514 icsk->icsk_ack.pingpong = 0;
2515 if ((1 << sk->sk_state) &
2516 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2517 inet_csk_ack_scheduled(sk)) {
2518 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2519 tcp_cleanup_rbuf(sk, 1);
2520 if (!(val & 1))
2521 icsk->icsk_ack.pingpong = 1;
2522 }
2523 }
2524 break;
2525
2526 #ifdef CONFIG_TCP_MD5SIG
2527 case TCP_MD5SIG:
2528 /* Read the IP->Key mappings from userspace */
2529 err = tp->af_specific->md5_parse(sk, optval, optlen);
2530 break;
2531 #endif
2532 case TCP_USER_TIMEOUT:
2533 /* Cap the max time in ms TCP will retry or probe the window
2534 * before giving up and aborting (ETIMEDOUT) a connection.
2535 */
2536 if (val < 0)
2537 err = -EINVAL;
2538 else
2539 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2540 break;
2541
2542 case TCP_FASTOPEN:
2543 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2544 TCPF_LISTEN)))
2545 err = fastopen_init_queue(sk, val);
2546 else
2547 err = -EINVAL;
2548 break;
2549 case TCP_TIMESTAMP:
2550 if (!tp->repair)
2551 err = -EPERM;
2552 else
2553 tp->tsoffset = val - tcp_time_stamp;
2554 break;
2555 case TCP_NOTSENT_LOWAT:
2556 tp->notsent_lowat = val;
2557 sk->sk_write_space(sk);
2558 break;
2559 default:
2560 err = -ENOPROTOOPT;
2561 break;
2562 }
2563
2564 release_sock(sk);
2565 return err;
2566 }
2567
2568 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2569 unsigned int optlen)
2570 {
2571 const struct inet_connection_sock *icsk = inet_csk(sk);
2572
2573 if (level != SOL_TCP)
2574 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2575 optval, optlen);
2576 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2577 }
2578 EXPORT_SYMBOL(tcp_setsockopt);
2579
2580 #ifdef CONFIG_COMPAT
2581 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2582 char __user *optval, unsigned int optlen)
2583 {
2584 if (level != SOL_TCP)
2585 return inet_csk_compat_setsockopt(sk, level, optname,
2586 optval, optlen);
2587 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2588 }
2589 EXPORT_SYMBOL(compat_tcp_setsockopt);
2590 #endif
2591
2592 /* Return information about state of tcp endpoint in API format. */
2593 void tcp_get_info(const struct sock *sk, struct tcp_info *info)
2594 {
2595 const struct tcp_sock *tp = tcp_sk(sk);
2596 const struct inet_connection_sock *icsk = inet_csk(sk);
2597 u32 now = tcp_time_stamp;
2598
2599 memset(info, 0, sizeof(*info));
2600
2601 info->tcpi_state = sk->sk_state;
2602 info->tcpi_ca_state = icsk->icsk_ca_state;
2603 info->tcpi_retransmits = icsk->icsk_retransmits;
2604 info->tcpi_probes = icsk->icsk_probes_out;
2605 info->tcpi_backoff = icsk->icsk_backoff;
2606
2607 if (tp->rx_opt.tstamp_ok)
2608 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2609 if (tcp_is_sack(tp))
2610 info->tcpi_options |= TCPI_OPT_SACK;
2611 if (tp->rx_opt.wscale_ok) {
2612 info->tcpi_options |= TCPI_OPT_WSCALE;
2613 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2614 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2615 }
2616
2617 if (tp->ecn_flags & TCP_ECN_OK)
2618 info->tcpi_options |= TCPI_OPT_ECN;
2619 if (tp->ecn_flags & TCP_ECN_SEEN)
2620 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2621 if (tp->syn_data_acked)
2622 info->tcpi_options |= TCPI_OPT_SYN_DATA;
2623
2624 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2625 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2626 info->tcpi_snd_mss = tp->mss_cache;
2627 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2628
2629 if (sk->sk_state == TCP_LISTEN) {
2630 info->tcpi_unacked = sk->sk_ack_backlog;
2631 info->tcpi_sacked = sk->sk_max_ack_backlog;
2632 } else {
2633 info->tcpi_unacked = tp->packets_out;
2634 info->tcpi_sacked = tp->sacked_out;
2635 }
2636 info->tcpi_lost = tp->lost_out;
2637 info->tcpi_retrans = tp->retrans_out;
2638 info->tcpi_fackets = tp->fackets_out;
2639
2640 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2641 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2642 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2643
2644 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2645 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2646 info->tcpi_rtt = tp->srtt_us >> 3;
2647 info->tcpi_rttvar = tp->mdev_us >> 2;
2648 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2649 info->tcpi_snd_cwnd = tp->snd_cwnd;
2650 info->tcpi_advmss = tp->advmss;
2651 info->tcpi_reordering = tp->reordering;
2652
2653 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2654 info->tcpi_rcv_space = tp->rcvq_space.space;
2655
2656 info->tcpi_total_retrans = tp->total_retrans;
2657
2658 info->tcpi_pacing_rate = sk->sk_pacing_rate != ~0U ?
2659 sk->sk_pacing_rate : ~0ULL;
2660 info->tcpi_max_pacing_rate = sk->sk_max_pacing_rate != ~0U ?
2661 sk->sk_max_pacing_rate : ~0ULL;
2662 }
2663 EXPORT_SYMBOL_GPL(tcp_get_info);
2664
2665 static int do_tcp_getsockopt(struct sock *sk, int level,
2666 int optname, char __user *optval, int __user *optlen)
2667 {
2668 struct inet_connection_sock *icsk = inet_csk(sk);
2669 struct tcp_sock *tp = tcp_sk(sk);
2670 int val, len;
2671
2672 if (get_user(len, optlen))
2673 return -EFAULT;
2674
2675 len = min_t(unsigned int, len, sizeof(int));
2676
2677 if (len < 0)
2678 return -EINVAL;
2679
2680 switch (optname) {
2681 case TCP_MAXSEG:
2682 val = tp->mss_cache;
2683 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2684 val = tp->rx_opt.user_mss;
2685 if (tp->repair)
2686 val = tp->rx_opt.mss_clamp;
2687 break;
2688 case TCP_NODELAY:
2689 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2690 break;
2691 case TCP_CORK:
2692 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2693 break;
2694 case TCP_KEEPIDLE:
2695 val = keepalive_time_when(tp) / HZ;
2696 break;
2697 case TCP_KEEPINTVL:
2698 val = keepalive_intvl_when(tp) / HZ;
2699 break;
2700 case TCP_KEEPCNT:
2701 val = keepalive_probes(tp);
2702 break;
2703 case TCP_SYNCNT:
2704 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2705 break;
2706 case TCP_LINGER2:
2707 val = tp->linger2;
2708 if (val >= 0)
2709 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2710 break;
2711 case TCP_DEFER_ACCEPT:
2712 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2713 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2714 break;
2715 case TCP_WINDOW_CLAMP:
2716 val = tp->window_clamp;
2717 break;
2718 case TCP_INFO: {
2719 struct tcp_info info;
2720
2721 if (get_user(len, optlen))
2722 return -EFAULT;
2723
2724 tcp_get_info(sk, &info);
2725
2726 len = min_t(unsigned int, len, sizeof(info));
2727 if (put_user(len, optlen))
2728 return -EFAULT;
2729 if (copy_to_user(optval, &info, len))
2730 return -EFAULT;
2731 return 0;
2732 }
2733 case TCP_QUICKACK:
2734 val = !icsk->icsk_ack.pingpong;
2735 break;
2736
2737 case TCP_CONGESTION:
2738 if (get_user(len, optlen))
2739 return -EFAULT;
2740 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2741 if (put_user(len, optlen))
2742 return -EFAULT;
2743 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2744 return -EFAULT;
2745 return 0;
2746
2747 case TCP_THIN_LINEAR_TIMEOUTS:
2748 val = tp->thin_lto;
2749 break;
2750 case TCP_THIN_DUPACK:
2751 val = tp->thin_dupack;
2752 break;
2753
2754 case TCP_REPAIR:
2755 val = tp->repair;
2756 break;
2757
2758 case TCP_REPAIR_QUEUE:
2759 if (tp->repair)
2760 val = tp->repair_queue;
2761 else
2762 return -EINVAL;
2763 break;
2764
2765 case TCP_QUEUE_SEQ:
2766 if (tp->repair_queue == TCP_SEND_QUEUE)
2767 val = tp->write_seq;
2768 else if (tp->repair_queue == TCP_RECV_QUEUE)
2769 val = tp->rcv_nxt;
2770 else
2771 return -EINVAL;
2772 break;
2773
2774 case TCP_USER_TIMEOUT:
2775 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2776 break;
2777
2778 case TCP_FASTOPEN:
2779 if (icsk->icsk_accept_queue.fastopenq != NULL)
2780 val = icsk->icsk_accept_queue.fastopenq->max_qlen;
2781 else
2782 val = 0;
2783 break;
2784
2785 case TCP_TIMESTAMP:
2786 val = tcp_time_stamp + tp->tsoffset;
2787 break;
2788 case TCP_NOTSENT_LOWAT:
2789 val = tp->notsent_lowat;
2790 break;
2791 default:
2792 return -ENOPROTOOPT;
2793 }
2794
2795 if (put_user(len, optlen))
2796 return -EFAULT;
2797 if (copy_to_user(optval, &val, len))
2798 return -EFAULT;
2799 return 0;
2800 }
2801
2802 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2803 int __user *optlen)
2804 {
2805 struct inet_connection_sock *icsk = inet_csk(sk);
2806
2807 if (level != SOL_TCP)
2808 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2809 optval, optlen);
2810 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2811 }
2812 EXPORT_SYMBOL(tcp_getsockopt);
2813
2814 #ifdef CONFIG_COMPAT
2815 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2816 char __user *optval, int __user *optlen)
2817 {
2818 if (level != SOL_TCP)
2819 return inet_csk_compat_getsockopt(sk, level, optname,
2820 optval, optlen);
2821 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2822 }
2823 EXPORT_SYMBOL(compat_tcp_getsockopt);
2824 #endif
2825
2826 #ifdef CONFIG_TCP_MD5SIG
2827 static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
2828 static DEFINE_MUTEX(tcp_md5sig_mutex);
2829 static bool tcp_md5sig_pool_populated = false;
2830
2831 static void __tcp_alloc_md5sig_pool(void)
2832 {
2833 int cpu;
2834
2835 for_each_possible_cpu(cpu) {
2836 if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) {
2837 struct crypto_hash *hash;
2838
2839 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2840 if (IS_ERR_OR_NULL(hash))
2841 return;
2842 per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm = hash;
2843 }
2844 }
2845 /* before setting tcp_md5sig_pool_populated, we must commit all writes
2846 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
2847 */
2848 smp_wmb();
2849 tcp_md5sig_pool_populated = true;
2850 }
2851
2852 bool tcp_alloc_md5sig_pool(void)
2853 {
2854 if (unlikely(!tcp_md5sig_pool_populated)) {
2855 mutex_lock(&tcp_md5sig_mutex);
2856
2857 if (!tcp_md5sig_pool_populated)
2858 __tcp_alloc_md5sig_pool();
2859
2860 mutex_unlock(&tcp_md5sig_mutex);
2861 }
2862 return tcp_md5sig_pool_populated;
2863 }
2864 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2865
2866
2867 /**
2868 * tcp_get_md5sig_pool - get md5sig_pool for this user
2869 *
2870 * We use percpu structure, so if we succeed, we exit with preemption
2871 * and BH disabled, to make sure another thread or softirq handling
2872 * wont try to get same context.
2873 */
2874 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2875 {
2876 local_bh_disable();
2877
2878 if (tcp_md5sig_pool_populated) {
2879 /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
2880 smp_rmb();
2881 return this_cpu_ptr(&tcp_md5sig_pool);
2882 }
2883 local_bh_enable();
2884 return NULL;
2885 }
2886 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2887
2888 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2889 const struct tcphdr *th)
2890 {
2891 struct scatterlist sg;
2892 struct tcphdr hdr;
2893 int err;
2894
2895 /* We are not allowed to change tcphdr, make a local copy */
2896 memcpy(&hdr, th, sizeof(hdr));
2897 hdr.check = 0;
2898
2899 /* options aren't included in the hash */
2900 sg_init_one(&sg, &hdr, sizeof(hdr));
2901 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
2902 return err;
2903 }
2904 EXPORT_SYMBOL(tcp_md5_hash_header);
2905
2906 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2907 const struct sk_buff *skb, unsigned int header_len)
2908 {
2909 struct scatterlist sg;
2910 const struct tcphdr *tp = tcp_hdr(skb);
2911 struct hash_desc *desc = &hp->md5_desc;
2912 unsigned int i;
2913 const unsigned int head_data_len = skb_headlen(skb) > header_len ?
2914 skb_headlen(skb) - header_len : 0;
2915 const struct skb_shared_info *shi = skb_shinfo(skb);
2916 struct sk_buff *frag_iter;
2917
2918 sg_init_table(&sg, 1);
2919
2920 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2921 if (crypto_hash_update(desc, &sg, head_data_len))
2922 return 1;
2923
2924 for (i = 0; i < shi->nr_frags; ++i) {
2925 const struct skb_frag_struct *f = &shi->frags[i];
2926 unsigned int offset = f->page_offset;
2927 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
2928
2929 sg_set_page(&sg, page, skb_frag_size(f),
2930 offset_in_page(offset));
2931 if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
2932 return 1;
2933 }
2934
2935 skb_walk_frags(skb, frag_iter)
2936 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
2937 return 1;
2938
2939 return 0;
2940 }
2941 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
2942
2943 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
2944 {
2945 struct scatterlist sg;
2946
2947 sg_init_one(&sg, key->key, key->keylen);
2948 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
2949 }
2950 EXPORT_SYMBOL(tcp_md5_hash_key);
2951
2952 #endif
2953
2954 void tcp_done(struct sock *sk)
2955 {
2956 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2957
2958 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2959 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
2960
2961 tcp_set_state(sk, TCP_CLOSE);
2962 tcp_clear_xmit_timers(sk);
2963 if (req != NULL)
2964 reqsk_fastopen_remove(sk, req, false);
2965
2966 sk->sk_shutdown = SHUTDOWN_MASK;
2967
2968 if (!sock_flag(sk, SOCK_DEAD))
2969 sk->sk_state_change(sk);
2970 else
2971 inet_csk_destroy_sock(sk);
2972 }
2973 EXPORT_SYMBOL_GPL(tcp_done);
2974
2975 extern struct tcp_congestion_ops tcp_reno;
2976
2977 static __initdata unsigned long thash_entries;
2978 static int __init set_thash_entries(char *str)
2979 {
2980 ssize_t ret;
2981
2982 if (!str)
2983 return 0;
2984
2985 ret = kstrtoul(str, 0, &thash_entries);
2986 if (ret)
2987 return 0;
2988
2989 return 1;
2990 }
2991 __setup("thash_entries=", set_thash_entries);
2992
2993 static void __init tcp_init_mem(void)
2994 {
2995 unsigned long limit = nr_free_buffer_pages() / 8;
2996 limit = max(limit, 128UL);
2997 sysctl_tcp_mem[0] = limit / 4 * 3;
2998 sysctl_tcp_mem[1] = limit;
2999 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3000 }
3001
3002 void __init tcp_init(void)
3003 {
3004 struct sk_buff *skb = NULL;
3005 unsigned long limit;
3006 int max_rshare, max_wshare, cnt;
3007 unsigned int i;
3008
3009 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3010
3011 percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
3012 percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3013 tcp_hashinfo.bind_bucket_cachep =
3014 kmem_cache_create("tcp_bind_bucket",
3015 sizeof(struct inet_bind_bucket), 0,
3016 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3017
3018 /* Size and allocate the main established and bind bucket
3019 * hash tables.
3020 *
3021 * The methodology is similar to that of the buffer cache.
3022 */
3023 tcp_hashinfo.ehash =
3024 alloc_large_system_hash("TCP established",
3025 sizeof(struct inet_ehash_bucket),
3026 thash_entries,
3027 17, /* one slot per 128 KB of memory */
3028 0,
3029 NULL,
3030 &tcp_hashinfo.ehash_mask,
3031 0,
3032 thash_entries ? 0 : 512 * 1024);
3033 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3034 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3035
3036 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3037 panic("TCP: failed to alloc ehash_locks");
3038 tcp_hashinfo.bhash =
3039 alloc_large_system_hash("TCP bind",
3040 sizeof(struct inet_bind_hashbucket),
3041 tcp_hashinfo.ehash_mask + 1,
3042 17, /* one slot per 128 KB of memory */
3043 0,
3044 &tcp_hashinfo.bhash_size,
3045 NULL,
3046 0,
3047 64 * 1024);
3048 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3049 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3050 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3051 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3052 }
3053
3054
3055 cnt = tcp_hashinfo.ehash_mask + 1;
3056
3057 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3058 sysctl_tcp_max_orphans = cnt / 2;
3059 sysctl_max_syn_backlog = max(128, cnt / 256);
3060
3061 tcp_init_mem();
3062 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3063 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3064 max_wshare = min(4UL*1024*1024, limit);
3065 max_rshare = min(6UL*1024*1024, limit);
3066
3067 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3068 sysctl_tcp_wmem[1] = 16*1024;
3069 sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3070
3071 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3072 sysctl_tcp_rmem[1] = 87380;
3073 sysctl_tcp_rmem[2] = max(87380, max_rshare);
3074
3075 pr_info("Hash tables configured (established %u bind %u)\n",
3076 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3077
3078 tcp_metrics_init();
3079 BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
3080 tcp_tasklet_init();
3081 }
Linux kernel - Deliverables
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