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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 <crypto/hash.h>
251 #include <linux/kernel.h>
252 #include <linux/module.h>
253 #include <linux/types.h>
254 #include <linux/fcntl.h>
255 #include <linux/poll.h>
256 #include <linux/inet_diag.h>
257 #include <linux/init.h>
258 #include <linux/fs.h>
259 #include <linux/skbuff.h>
260 #include <linux/scatterlist.h>
261 #include <linux/splice.h>
262 #include <linux/net.h>
263 #include <linux/socket.h>
264 #include <linux/random.h>
265 #include <linux/bootmem.h>
266 #include <linux/highmem.h>
267 #include <linux/swap.h>
268 #include <linux/cache.h>
269 #include <linux/err.h>
270 #include <linux/time.h>
271 #include <linux/slab.h>
272
273 #include <net/icmp.h>
274 #include <net/inet_common.h>
275 #include <net/tcp.h>
276 #include <net/xfrm.h>
277 #include <net/ip.h>
278 #include <net/sock.h>
279
280 #include <asm/uaccess.h>
281 #include <asm/ioctls.h>
282 #include <asm/unaligned.h>
283 #include <net/busy_poll.h>
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 tp->out_of_order_queue = RB_ROOT;
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 minmax_reset(&tp->rtt_min, tcp_time_stamp, ~0U);
391
392 /* So many TCP implementations out there (incorrectly) count the
393 * initial SYN frame in their delayed-ACK and congestion control
394 * algorithms that we must have the following bandaid to talk
395 * efficiently to them. -DaveM
396 */
397 tp->snd_cwnd = TCP_INIT_CWND;
398
399 /* There's a bubble in the pipe until at least the first ACK. */
400 tp->app_limited = ~0U;
401
402 /* See draft-stevens-tcpca-spec-01 for discussion of the
403 * initialization of these values.
404 */
405 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
406 tp->snd_cwnd_clamp = ~0;
407 tp->mss_cache = TCP_MSS_DEFAULT;
408 u64_stats_init(&tp->syncp);
409
410 tp->reordering = sock_net(sk)->ipv4.sysctl_tcp_reordering;
411 tcp_enable_early_retrans(tp);
412 tcp_assign_congestion_control(sk);
413
414 tp->tsoffset = 0;
415
416 sk->sk_state = TCP_CLOSE;
417
418 sk->sk_write_space = sk_stream_write_space;
419 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
420
421 icsk->icsk_sync_mss = tcp_sync_mss;
422
423 sk->sk_sndbuf = sysctl_tcp_wmem[1];
424 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
425
426 local_bh_disable();
427 sk_sockets_allocated_inc(sk);
428 local_bh_enable();
429 }
430 EXPORT_SYMBOL(tcp_init_sock);
431
432 static void tcp_tx_timestamp(struct sock *sk, u16 tsflags, struct sk_buff *skb)
433 {
434 if (tsflags) {
435 struct skb_shared_info *shinfo = skb_shinfo(skb);
436 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
437
438 sock_tx_timestamp(sk, tsflags, &shinfo->tx_flags);
439 if (tsflags & SOF_TIMESTAMPING_TX_ACK)
440 tcb->txstamp_ack = 1;
441 if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
442 shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
443 }
444 }
445
446 /*
447 * Wait for a TCP event.
448 *
449 * Note that we don't need to lock the socket, as the upper poll layers
450 * take care of normal races (between the test and the event) and we don't
451 * go look at any of the socket buffers directly.
452 */
453 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
454 {
455 unsigned int mask;
456 struct sock *sk = sock->sk;
457 const struct tcp_sock *tp = tcp_sk(sk);
458 int state;
459
460 sock_rps_record_flow(sk);
461
462 sock_poll_wait(file, sk_sleep(sk), wait);
463
464 state = sk_state_load(sk);
465 if (state == TCP_LISTEN)
466 return inet_csk_listen_poll(sk);
467
468 /* Socket is not locked. We are protected from async events
469 * by poll logic and correct handling of state changes
470 * made by other threads is impossible in any case.
471 */
472
473 mask = 0;
474
475 /*
476 * POLLHUP is certainly not done right. But poll() doesn't
477 * have a notion of HUP in just one direction, and for a
478 * socket the read side is more interesting.
479 *
480 * Some poll() documentation says that POLLHUP is incompatible
481 * with the POLLOUT/POLLWR flags, so somebody should check this
482 * all. But careful, it tends to be safer to return too many
483 * bits than too few, and you can easily break real applications
484 * if you don't tell them that something has hung up!
485 *
486 * Check-me.
487 *
488 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
489 * our fs/select.c). It means that after we received EOF,
490 * poll always returns immediately, making impossible poll() on write()
491 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
492 * if and only if shutdown has been made in both directions.
493 * Actually, it is interesting to look how Solaris and DUX
494 * solve this dilemma. I would prefer, if POLLHUP were maskable,
495 * then we could set it on SND_SHUTDOWN. BTW examples given
496 * in Stevens' books assume exactly this behaviour, it explains
497 * why POLLHUP is incompatible with POLLOUT. --ANK
498 *
499 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
500 * blocking on fresh not-connected or disconnected socket. --ANK
501 */
502 if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
503 mask |= POLLHUP;
504 if (sk->sk_shutdown & RCV_SHUTDOWN)
505 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
506
507 /* Connected or passive Fast Open socket? */
508 if (state != TCP_SYN_SENT &&
509 (state != TCP_SYN_RECV || tp->fastopen_rsk)) {
510 int target = sock_rcvlowat(sk, 0, INT_MAX);
511
512 if (tp->urg_seq == tp->copied_seq &&
513 !sock_flag(sk, SOCK_URGINLINE) &&
514 tp->urg_data)
515 target++;
516
517 if (tp->rcv_nxt - tp->copied_seq >= target)
518 mask |= POLLIN | POLLRDNORM;
519
520 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
521 if (sk_stream_is_writeable(sk)) {
522 mask |= POLLOUT | POLLWRNORM;
523 } else { /* send SIGIO later */
524 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
525 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
526
527 /* Race breaker. If space is freed after
528 * wspace test but before the flags are set,
529 * IO signal will be lost. Memory barrier
530 * pairs with the input side.
531 */
532 smp_mb__after_atomic();
533 if (sk_stream_is_writeable(sk))
534 mask |= POLLOUT | POLLWRNORM;
535 }
536 } else
537 mask |= POLLOUT | POLLWRNORM;
538
539 if (tp->urg_data & TCP_URG_VALID)
540 mask |= POLLPRI;
541 }
542 /* This barrier is coupled with smp_wmb() in tcp_reset() */
543 smp_rmb();
544 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
545 mask |= POLLERR;
546
547 return mask;
548 }
549 EXPORT_SYMBOL(tcp_poll);
550
551 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
552 {
553 struct tcp_sock *tp = tcp_sk(sk);
554 int answ;
555 bool slow;
556
557 switch (cmd) {
558 case SIOCINQ:
559 if (sk->sk_state == TCP_LISTEN)
560 return -EINVAL;
561
562 slow = lock_sock_fast(sk);
563 answ = tcp_inq(sk);
564 unlock_sock_fast(sk, slow);
565 break;
566 case SIOCATMARK:
567 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
568 break;
569 case SIOCOUTQ:
570 if (sk->sk_state == TCP_LISTEN)
571 return -EINVAL;
572
573 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
574 answ = 0;
575 else
576 answ = tp->write_seq - tp->snd_una;
577 break;
578 case SIOCOUTQNSD:
579 if (sk->sk_state == TCP_LISTEN)
580 return -EINVAL;
581
582 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
583 answ = 0;
584 else
585 answ = tp->write_seq - tp->snd_nxt;
586 break;
587 default:
588 return -ENOIOCTLCMD;
589 }
590
591 return put_user(answ, (int __user *)arg);
592 }
593 EXPORT_SYMBOL(tcp_ioctl);
594
595 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
596 {
597 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
598 tp->pushed_seq = tp->write_seq;
599 }
600
601 static inline bool forced_push(const struct tcp_sock *tp)
602 {
603 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
604 }
605
606 static void skb_entail(struct sock *sk, struct sk_buff *skb)
607 {
608 struct tcp_sock *tp = tcp_sk(sk);
609 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
610
611 skb->csum = 0;
612 tcb->seq = tcb->end_seq = tp->write_seq;
613 tcb->tcp_flags = TCPHDR_ACK;
614 tcb->sacked = 0;
615 __skb_header_release(skb);
616 tcp_add_write_queue_tail(sk, skb);
617 sk->sk_wmem_queued += skb->truesize;
618 sk_mem_charge(sk, skb->truesize);
619 if (tp->nonagle & TCP_NAGLE_PUSH)
620 tp->nonagle &= ~TCP_NAGLE_PUSH;
621
622 tcp_slow_start_after_idle_check(sk);
623 }
624
625 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
626 {
627 if (flags & MSG_OOB)
628 tp->snd_up = tp->write_seq;
629 }
630
631 /* If a not yet filled skb is pushed, do not send it if
632 * we have data packets in Qdisc or NIC queues :
633 * Because TX completion will happen shortly, it gives a chance
634 * to coalesce future sendmsg() payload into this skb, without
635 * need for a timer, and with no latency trade off.
636 * As packets containing data payload have a bigger truesize
637 * than pure acks (dataless) packets, the last checks prevent
638 * autocorking if we only have an ACK in Qdisc/NIC queues,
639 * or if TX completion was delayed after we processed ACK packet.
640 */
641 static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
642 int size_goal)
643 {
644 return skb->len < size_goal &&
645 sysctl_tcp_autocorking &&
646 skb != tcp_write_queue_head(sk) &&
647 atomic_read(&sk->sk_wmem_alloc) > skb->truesize;
648 }
649
650 static void tcp_push(struct sock *sk, int flags, int mss_now,
651 int nonagle, int size_goal)
652 {
653 struct tcp_sock *tp = tcp_sk(sk);
654 struct sk_buff *skb;
655
656 if (!tcp_send_head(sk))
657 return;
658
659 skb = tcp_write_queue_tail(sk);
660 if (!(flags & MSG_MORE) || forced_push(tp))
661 tcp_mark_push(tp, skb);
662
663 tcp_mark_urg(tp, flags);
664
665 if (tcp_should_autocork(sk, skb, size_goal)) {
666
667 /* avoid atomic op if TSQ_THROTTLED bit is already set */
668 if (!test_bit(TSQ_THROTTLED, &tp->tsq_flags)) {
669 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
670 set_bit(TSQ_THROTTLED, &tp->tsq_flags);
671 }
672 /* It is possible TX completion already happened
673 * before we set TSQ_THROTTLED.
674 */
675 if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize)
676 return;
677 }
678
679 if (flags & MSG_MORE)
680 nonagle = TCP_NAGLE_CORK;
681
682 __tcp_push_pending_frames(sk, mss_now, nonagle);
683 }
684
685 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
686 unsigned int offset, size_t len)
687 {
688 struct tcp_splice_state *tss = rd_desc->arg.data;
689 int ret;
690
691 ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
692 min(rd_desc->count, len), tss->flags);
693 if (ret > 0)
694 rd_desc->count -= ret;
695 return ret;
696 }
697
698 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
699 {
700 /* Store TCP splice context information in read_descriptor_t. */
701 read_descriptor_t rd_desc = {
702 .arg.data = tss,
703 .count = tss->len,
704 };
705
706 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
707 }
708
709 /**
710 * tcp_splice_read - splice data from TCP socket to a pipe
711 * @sock: socket to splice from
712 * @ppos: position (not valid)
713 * @pipe: pipe to splice to
714 * @len: number of bytes to splice
715 * @flags: splice modifier flags
716 *
717 * Description:
718 * Will read pages from given socket and fill them into a pipe.
719 *
720 **/
721 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
722 struct pipe_inode_info *pipe, size_t len,
723 unsigned int flags)
724 {
725 struct sock *sk = sock->sk;
726 struct tcp_splice_state tss = {
727 .pipe = pipe,
728 .len = len,
729 .flags = flags,
730 };
731 long timeo;
732 ssize_t spliced;
733 int ret;
734
735 sock_rps_record_flow(sk);
736 /*
737 * We can't seek on a socket input
738 */
739 if (unlikely(*ppos))
740 return -ESPIPE;
741
742 ret = spliced = 0;
743
744 lock_sock(sk);
745
746 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
747 while (tss.len) {
748 ret = __tcp_splice_read(sk, &tss);
749 if (ret < 0)
750 break;
751 else if (!ret) {
752 if (spliced)
753 break;
754 if (sock_flag(sk, SOCK_DONE))
755 break;
756 if (sk->sk_err) {
757 ret = sock_error(sk);
758 break;
759 }
760 if (sk->sk_shutdown & RCV_SHUTDOWN)
761 break;
762 if (sk->sk_state == TCP_CLOSE) {
763 /*
764 * This occurs when user tries to read
765 * from never connected socket.
766 */
767 if (!sock_flag(sk, SOCK_DONE))
768 ret = -ENOTCONN;
769 break;
770 }
771 if (!timeo) {
772 ret = -EAGAIN;
773 break;
774 }
775 sk_wait_data(sk, &timeo, NULL);
776 if (signal_pending(current)) {
777 ret = sock_intr_errno(timeo);
778 break;
779 }
780 continue;
781 }
782 tss.len -= ret;
783 spliced += ret;
784
785 if (!timeo)
786 break;
787 release_sock(sk);
788 lock_sock(sk);
789
790 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
791 (sk->sk_shutdown & RCV_SHUTDOWN) ||
792 signal_pending(current))
793 break;
794 }
795
796 release_sock(sk);
797
798 if (spliced)
799 return spliced;
800
801 return ret;
802 }
803 EXPORT_SYMBOL(tcp_splice_read);
804
805 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
806 bool force_schedule)
807 {
808 struct sk_buff *skb;
809
810 /* The TCP header must be at least 32-bit aligned. */
811 size = ALIGN(size, 4);
812
813 if (unlikely(tcp_under_memory_pressure(sk)))
814 sk_mem_reclaim_partial(sk);
815
816 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
817 if (likely(skb)) {
818 bool mem_scheduled;
819
820 if (force_schedule) {
821 mem_scheduled = true;
822 sk_forced_mem_schedule(sk, skb->truesize);
823 } else {
824 mem_scheduled = sk_wmem_schedule(sk, skb->truesize);
825 }
826 if (likely(mem_scheduled)) {
827 skb_reserve(skb, sk->sk_prot->max_header);
828 /*
829 * Make sure that we have exactly size bytes
830 * available to the caller, no more, no less.
831 */
832 skb->reserved_tailroom = skb->end - skb->tail - size;
833 return skb;
834 }
835 __kfree_skb(skb);
836 } else {
837 sk->sk_prot->enter_memory_pressure(sk);
838 sk_stream_moderate_sndbuf(sk);
839 }
840 return NULL;
841 }
842
843 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
844 int large_allowed)
845 {
846 struct tcp_sock *tp = tcp_sk(sk);
847 u32 new_size_goal, size_goal;
848
849 if (!large_allowed || !sk_can_gso(sk))
850 return mss_now;
851
852 /* Note : tcp_tso_autosize() will eventually split this later */
853 new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER;
854 new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);
855
856 /* We try hard to avoid divides here */
857 size_goal = tp->gso_segs * mss_now;
858 if (unlikely(new_size_goal < size_goal ||
859 new_size_goal >= size_goal + mss_now)) {
860 tp->gso_segs = min_t(u16, new_size_goal / mss_now,
861 sk->sk_gso_max_segs);
862 size_goal = tp->gso_segs * mss_now;
863 }
864
865 return max(size_goal, mss_now);
866 }
867
868 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
869 {
870 int mss_now;
871
872 mss_now = tcp_current_mss(sk);
873 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
874
875 return mss_now;
876 }
877
878 static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
879 size_t size, int flags)
880 {
881 struct tcp_sock *tp = tcp_sk(sk);
882 int mss_now, size_goal;
883 int err;
884 ssize_t copied;
885 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
886
887 /* Wait for a connection to finish. One exception is TCP Fast Open
888 * (passive side) where data is allowed to be sent before a connection
889 * is fully established.
890 */
891 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
892 !tcp_passive_fastopen(sk)) {
893 err = sk_stream_wait_connect(sk, &timeo);
894 if (err != 0)
895 goto out_err;
896 }
897
898 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
899
900 mss_now = tcp_send_mss(sk, &size_goal, flags);
901 copied = 0;
902
903 err = -EPIPE;
904 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
905 goto out_err;
906
907 while (size > 0) {
908 struct sk_buff *skb = tcp_write_queue_tail(sk);
909 int copy, i;
910 bool can_coalesce;
911
912 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0 ||
913 !tcp_skb_can_collapse_to(skb)) {
914 new_segment:
915 if (!sk_stream_memory_free(sk))
916 goto wait_for_sndbuf;
917
918 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
919 skb_queue_empty(&sk->sk_write_queue));
920 if (!skb)
921 goto wait_for_memory;
922
923 skb_entail(sk, skb);
924 copy = size_goal;
925 }
926
927 if (copy > size)
928 copy = size;
929
930 i = skb_shinfo(skb)->nr_frags;
931 can_coalesce = skb_can_coalesce(skb, i, page, offset);
932 if (!can_coalesce && i >= sysctl_max_skb_frags) {
933 tcp_mark_push(tp, skb);
934 goto new_segment;
935 }
936 if (!sk_wmem_schedule(sk, copy))
937 goto wait_for_memory;
938
939 if (can_coalesce) {
940 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
941 } else {
942 get_page(page);
943 skb_fill_page_desc(skb, i, page, offset, copy);
944 }
945 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
946
947 skb->len += copy;
948 skb->data_len += copy;
949 skb->truesize += copy;
950 sk->sk_wmem_queued += copy;
951 sk_mem_charge(sk, copy);
952 skb->ip_summed = CHECKSUM_PARTIAL;
953 tp->write_seq += copy;
954 TCP_SKB_CB(skb)->end_seq += copy;
955 tcp_skb_pcount_set(skb, 0);
956
957 if (!copied)
958 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
959
960 copied += copy;
961 offset += copy;
962 size -= copy;
963 if (!size) {
964 tcp_tx_timestamp(sk, sk->sk_tsflags, skb);
965 goto out;
966 }
967
968 if (skb->len < size_goal || (flags & MSG_OOB))
969 continue;
970
971 if (forced_push(tp)) {
972 tcp_mark_push(tp, skb);
973 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
974 } else if (skb == tcp_send_head(sk))
975 tcp_push_one(sk, mss_now);
976 continue;
977
978 wait_for_sndbuf:
979 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
980 wait_for_memory:
981 tcp_push(sk, flags & ~MSG_MORE, mss_now,
982 TCP_NAGLE_PUSH, size_goal);
983
984 err = sk_stream_wait_memory(sk, &timeo);
985 if (err != 0)
986 goto do_error;
987
988 mss_now = tcp_send_mss(sk, &size_goal, flags);
989 }
990
991 out:
992 if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
993 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
994 return copied;
995
996 do_error:
997 if (copied)
998 goto out;
999 out_err:
1000 /* make sure we wake any epoll edge trigger waiter */
1001 if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
1002 sk->sk_write_space(sk);
1003 return sk_stream_error(sk, flags, err);
1004 }
1005
1006 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
1007 size_t size, int flags)
1008 {
1009 ssize_t res;
1010
1011 if (!(sk->sk_route_caps & NETIF_F_SG) ||
1012 !sk_check_csum_caps(sk))
1013 return sock_no_sendpage(sk->sk_socket, page, offset, size,
1014 flags);
1015
1016 lock_sock(sk);
1017
1018 tcp_rate_check_app_limited(sk); /* is sending application-limited? */
1019
1020 res = do_tcp_sendpages(sk, page, offset, size, flags);
1021 release_sock(sk);
1022 return res;
1023 }
1024 EXPORT_SYMBOL(tcp_sendpage);
1025
1026 /* Do not bother using a page frag for very small frames.
1027 * But use this heuristic only for the first skb in write queue.
1028 *
1029 * Having no payload in skb->head allows better SACK shifting
1030 * in tcp_shift_skb_data(), reducing sack/rack overhead, because
1031 * write queue has less skbs.
1032 * Each skb can hold up to MAX_SKB_FRAGS * 32Kbytes, or ~0.5 MB.
1033 * This also speeds up tso_fragment(), since it wont fallback
1034 * to tcp_fragment().
1035 */
1036 static int linear_payload_sz(bool first_skb)
1037 {
1038 if (first_skb)
1039 return SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
1040 return 0;
1041 }
1042
1043 static int select_size(const struct sock *sk, bool sg, bool first_skb)
1044 {
1045 const struct tcp_sock *tp = tcp_sk(sk);
1046 int tmp = tp->mss_cache;
1047
1048 if (sg) {
1049 if (sk_can_gso(sk)) {
1050 tmp = linear_payload_sz(first_skb);
1051 } else {
1052 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
1053
1054 if (tmp >= pgbreak &&
1055 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
1056 tmp = pgbreak;
1057 }
1058 }
1059
1060 return tmp;
1061 }
1062
1063 void tcp_free_fastopen_req(struct tcp_sock *tp)
1064 {
1065 if (tp->fastopen_req) {
1066 kfree(tp->fastopen_req);
1067 tp->fastopen_req = NULL;
1068 }
1069 }
1070
1071 static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1072 int *copied, size_t size)
1073 {
1074 struct tcp_sock *tp = tcp_sk(sk);
1075 int err, flags;
1076
1077 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
1078 return -EOPNOTSUPP;
1079 if (tp->fastopen_req)
1080 return -EALREADY; /* Another Fast Open is in progress */
1081
1082 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1083 sk->sk_allocation);
1084 if (unlikely(!tp->fastopen_req))
1085 return -ENOBUFS;
1086 tp->fastopen_req->data = msg;
1087 tp->fastopen_req->size = size;
1088
1089 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1090 err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1091 msg->msg_namelen, flags);
1092 *copied = tp->fastopen_req->copied;
1093 tcp_free_fastopen_req(tp);
1094 return err;
1095 }
1096
1097 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
1098 {
1099 struct tcp_sock *tp = tcp_sk(sk);
1100 struct sk_buff *skb;
1101 struct sockcm_cookie sockc;
1102 int flags, err, copied = 0;
1103 int mss_now = 0, size_goal, copied_syn = 0;
1104 bool process_backlog = false;
1105 bool sg;
1106 long timeo;
1107
1108 lock_sock(sk);
1109
1110 flags = msg->msg_flags;
1111 if (flags & MSG_FASTOPEN) {
1112 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1113 if (err == -EINPROGRESS && copied_syn > 0)
1114 goto out;
1115 else if (err)
1116 goto out_err;
1117 }
1118
1119 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1120
1121 tcp_rate_check_app_limited(sk); /* is sending application-limited? */
1122
1123 /* Wait for a connection to finish. One exception is TCP Fast Open
1124 * (passive side) where data is allowed to be sent before a connection
1125 * is fully established.
1126 */
1127 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1128 !tcp_passive_fastopen(sk)) {
1129 err = sk_stream_wait_connect(sk, &timeo);
1130 if (err != 0)
1131 goto do_error;
1132 }
1133
1134 if (unlikely(tp->repair)) {
1135 if (tp->repair_queue == TCP_RECV_QUEUE) {
1136 copied = tcp_send_rcvq(sk, msg, size);
1137 goto out_nopush;
1138 }
1139
1140 err = -EINVAL;
1141 if (tp->repair_queue == TCP_NO_QUEUE)
1142 goto out_err;
1143
1144 /* 'common' sending to sendq */
1145 }
1146
1147 sockc.tsflags = sk->sk_tsflags;
1148 if (msg->msg_controllen) {
1149 err = sock_cmsg_send(sk, msg, &sockc);
1150 if (unlikely(err)) {
1151 err = -EINVAL;
1152 goto out_err;
1153 }
1154 }
1155
1156 /* This should be in poll */
1157 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
1158
1159 /* Ok commence sending. */
1160 copied = 0;
1161
1162 restart:
1163 mss_now = tcp_send_mss(sk, &size_goal, flags);
1164
1165 err = -EPIPE;
1166 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1167 goto out_err;
1168
1169 sg = !!(sk->sk_route_caps & NETIF_F_SG);
1170
1171 while (msg_data_left(msg)) {
1172 int copy = 0;
1173 int max = size_goal;
1174
1175 skb = tcp_write_queue_tail(sk);
1176 if (tcp_send_head(sk)) {
1177 if (skb->ip_summed == CHECKSUM_NONE)
1178 max = mss_now;
1179 copy = max - skb->len;
1180 }
1181
1182 if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) {
1183 bool first_skb;
1184
1185 new_segment:
1186 /* Allocate new segment. If the interface is SG,
1187 * allocate skb fitting to single page.
1188 */
1189 if (!sk_stream_memory_free(sk))
1190 goto wait_for_sndbuf;
1191
1192 if (process_backlog && sk_flush_backlog(sk)) {
1193 process_backlog = false;
1194 goto restart;
1195 }
1196 first_skb = skb_queue_empty(&sk->sk_write_queue);
1197 skb = sk_stream_alloc_skb(sk,
1198 select_size(sk, sg, first_skb),
1199 sk->sk_allocation,
1200 first_skb);
1201 if (!skb)
1202 goto wait_for_memory;
1203
1204 process_backlog = true;
1205 /*
1206 * Check whether we can use HW checksum.
1207 */
1208 if (sk_check_csum_caps(sk))
1209 skb->ip_summed = CHECKSUM_PARTIAL;
1210
1211 skb_entail(sk, skb);
1212 copy = size_goal;
1213 max = size_goal;
1214
1215 /* All packets are restored as if they have
1216 * already been sent. skb_mstamp isn't set to
1217 * avoid wrong rtt estimation.
1218 */
1219 if (tp->repair)
1220 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
1221 }
1222
1223 /* Try to append data to the end of skb. */
1224 if (copy > msg_data_left(msg))
1225 copy = msg_data_left(msg);
1226
1227 /* Where to copy to? */
1228 if (skb_availroom(skb) > 0) {
1229 /* We have some space in skb head. Superb! */
1230 copy = min_t(int, copy, skb_availroom(skb));
1231 err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);
1232 if (err)
1233 goto do_fault;
1234 } else {
1235 bool merge = true;
1236 int i = skb_shinfo(skb)->nr_frags;
1237 struct page_frag *pfrag = sk_page_frag(sk);
1238
1239 if (!sk_page_frag_refill(sk, pfrag))
1240 goto wait_for_memory;
1241
1242 if (!skb_can_coalesce(skb, i, pfrag->page,
1243 pfrag->offset)) {
1244 if (i == sysctl_max_skb_frags || !sg) {
1245 tcp_mark_push(tp, skb);
1246 goto new_segment;
1247 }
1248 merge = false;
1249 }
1250
1251 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1252
1253 if (!sk_wmem_schedule(sk, copy))
1254 goto wait_for_memory;
1255
1256 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
1257 pfrag->page,
1258 pfrag->offset,
1259 copy);
1260 if (err)
1261 goto do_error;
1262
1263 /* Update the skb. */
1264 if (merge) {
1265 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1266 } else {
1267 skb_fill_page_desc(skb, i, pfrag->page,
1268 pfrag->offset, copy);
1269 get_page(pfrag->page);
1270 }
1271 pfrag->offset += copy;
1272 }
1273
1274 if (!copied)
1275 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1276
1277 tp->write_seq += copy;
1278 TCP_SKB_CB(skb)->end_seq += copy;
1279 tcp_skb_pcount_set(skb, 0);
1280
1281 copied += copy;
1282 if (!msg_data_left(msg)) {
1283 tcp_tx_timestamp(sk, sockc.tsflags, skb);
1284 if (unlikely(flags & MSG_EOR))
1285 TCP_SKB_CB(skb)->eor = 1;
1286 goto out;
1287 }
1288
1289 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1290 continue;
1291
1292 if (forced_push(tp)) {
1293 tcp_mark_push(tp, skb);
1294 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1295 } else if (skb == tcp_send_head(sk))
1296 tcp_push_one(sk, mss_now);
1297 continue;
1298
1299 wait_for_sndbuf:
1300 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1301 wait_for_memory:
1302 if (copied)
1303 tcp_push(sk, flags & ~MSG_MORE, mss_now,
1304 TCP_NAGLE_PUSH, size_goal);
1305
1306 err = sk_stream_wait_memory(sk, &timeo);
1307 if (err != 0)
1308 goto do_error;
1309
1310 mss_now = tcp_send_mss(sk, &size_goal, flags);
1311 }
1312
1313 out:
1314 if (copied)
1315 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1316 out_nopush:
1317 release_sock(sk);
1318 return copied + copied_syn;
1319
1320 do_fault:
1321 if (!skb->len) {
1322 tcp_unlink_write_queue(skb, sk);
1323 /* It is the one place in all of TCP, except connection
1324 * reset, where we can be unlinking the send_head.
1325 */
1326 tcp_check_send_head(sk, skb);
1327 sk_wmem_free_skb(sk, skb);
1328 }
1329
1330 do_error:
1331 if (copied + copied_syn)
1332 goto out;
1333 out_err:
1334 err = sk_stream_error(sk, flags, err);
1335 /* make sure we wake any epoll edge trigger waiter */
1336 if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
1337 sk->sk_write_space(sk);
1338 release_sock(sk);
1339 return err;
1340 }
1341 EXPORT_SYMBOL(tcp_sendmsg);
1342
1343 /*
1344 * Handle reading urgent data. BSD has very simple semantics for
1345 * this, no blocking and very strange errors 8)
1346 */
1347
1348 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1349 {
1350 struct tcp_sock *tp = tcp_sk(sk);
1351
1352 /* No URG data to read. */
1353 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1354 tp->urg_data == TCP_URG_READ)
1355 return -EINVAL; /* Yes this is right ! */
1356
1357 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1358 return -ENOTCONN;
1359
1360 if (tp->urg_data & TCP_URG_VALID) {
1361 int err = 0;
1362 char c = tp->urg_data;
1363
1364 if (!(flags & MSG_PEEK))
1365 tp->urg_data = TCP_URG_READ;
1366
1367 /* Read urgent data. */
1368 msg->msg_flags |= MSG_OOB;
1369
1370 if (len > 0) {
1371 if (!(flags & MSG_TRUNC))
1372 err = memcpy_to_msg(msg, &c, 1);
1373 len = 1;
1374 } else
1375 msg->msg_flags |= MSG_TRUNC;
1376
1377 return err ? -EFAULT : len;
1378 }
1379
1380 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1381 return 0;
1382
1383 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1384 * the available implementations agree in this case:
1385 * this call should never block, independent of the
1386 * blocking state of the socket.
1387 * Mike <pall@rz.uni-karlsruhe.de>
1388 */
1389 return -EAGAIN;
1390 }
1391
1392 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1393 {
1394 struct sk_buff *skb;
1395 int copied = 0, err = 0;
1396
1397 /* XXX -- need to support SO_PEEK_OFF */
1398
1399 skb_queue_walk(&sk->sk_write_queue, skb) {
1400 err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
1401 if (err)
1402 break;
1403
1404 copied += skb->len;
1405 }
1406
1407 return err ?: copied;
1408 }
1409
1410 /* Clean up the receive buffer for full frames taken by the user,
1411 * then send an ACK if necessary. COPIED is the number of bytes
1412 * tcp_recvmsg has given to the user so far, it speeds up the
1413 * calculation of whether or not we must ACK for the sake of
1414 * a window update.
1415 */
1416 static void tcp_cleanup_rbuf(struct sock *sk, int copied)
1417 {
1418 struct tcp_sock *tp = tcp_sk(sk);
1419 bool time_to_ack = false;
1420
1421 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1422
1423 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1424 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1425 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1426
1427 if (inet_csk_ack_scheduled(sk)) {
1428 const struct inet_connection_sock *icsk = inet_csk(sk);
1429 /* Delayed ACKs frequently hit locked sockets during bulk
1430 * receive. */
1431 if (icsk->icsk_ack.blocked ||
1432 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1433 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1434 /*
1435 * If this read emptied read buffer, we send ACK, if
1436 * connection is not bidirectional, user drained
1437 * receive buffer and there was a small segment
1438 * in queue.
1439 */
1440 (copied > 0 &&
1441 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1442 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1443 !icsk->icsk_ack.pingpong)) &&
1444 !atomic_read(&sk->sk_rmem_alloc)))
1445 time_to_ack = true;
1446 }
1447
1448 /* We send an ACK if we can now advertise a non-zero window
1449 * which has been raised "significantly".
1450 *
1451 * Even if window raised up to infinity, do not send window open ACK
1452 * in states, where we will not receive more. It is useless.
1453 */
1454 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1455 __u32 rcv_window_now = tcp_receive_window(tp);
1456
1457 /* Optimize, __tcp_select_window() is not cheap. */
1458 if (2*rcv_window_now <= tp->window_clamp) {
1459 __u32 new_window = __tcp_select_window(sk);
1460
1461 /* Send ACK now, if this read freed lots of space
1462 * in our buffer. Certainly, new_window is new window.
1463 * We can advertise it now, if it is not less than current one.
1464 * "Lots" means "at least twice" here.
1465 */
1466 if (new_window && new_window >= 2 * rcv_window_now)
1467 time_to_ack = true;
1468 }
1469 }
1470 if (time_to_ack)
1471 tcp_send_ack(sk);
1472 }
1473
1474 static void tcp_prequeue_process(struct sock *sk)
1475 {
1476 struct sk_buff *skb;
1477 struct tcp_sock *tp = tcp_sk(sk);
1478
1479 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1480
1481 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1482 sk_backlog_rcv(sk, skb);
1483
1484 /* Clear memory counter. */
1485 tp->ucopy.memory = 0;
1486 }
1487
1488 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1489 {
1490 struct sk_buff *skb;
1491 u32 offset;
1492
1493 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1494 offset = seq - TCP_SKB_CB(skb)->seq;
1495 if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
1496 pr_err_once("%s: found a SYN, please report !\n", __func__);
1497 offset--;
1498 }
1499 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
1500 *off = offset;
1501 return skb;
1502 }
1503 /* This looks weird, but this can happen if TCP collapsing
1504 * splitted a fat GRO packet, while we released socket lock
1505 * in skb_splice_bits()
1506 */
1507 sk_eat_skb(sk, skb);
1508 }
1509 return NULL;
1510 }
1511
1512 /*
1513 * This routine provides an alternative to tcp_recvmsg() for routines
1514 * that would like to handle copying from skbuffs directly in 'sendfile'
1515 * fashion.
1516 * Note:
1517 * - It is assumed that the socket was locked by the caller.
1518 * - The routine does not block.
1519 * - At present, there is no support for reading OOB data
1520 * or for 'peeking' the socket using this routine
1521 * (although both would be easy to implement).
1522 */
1523 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1524 sk_read_actor_t recv_actor)
1525 {
1526 struct sk_buff *skb;
1527 struct tcp_sock *tp = tcp_sk(sk);
1528 u32 seq = tp->copied_seq;
1529 u32 offset;
1530 int copied = 0;
1531
1532 if (sk->sk_state == TCP_LISTEN)
1533 return -ENOTCONN;
1534 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1535 if (offset < skb->len) {
1536 int used;
1537 size_t len;
1538
1539 len = skb->len - offset;
1540 /* Stop reading if we hit a patch of urgent data */
1541 if (tp->urg_data) {
1542 u32 urg_offset = tp->urg_seq - seq;
1543 if (urg_offset < len)
1544 len = urg_offset;
1545 if (!len)
1546 break;
1547 }
1548 used = recv_actor(desc, skb, offset, len);
1549 if (used <= 0) {
1550 if (!copied)
1551 copied = used;
1552 break;
1553 } else if (used <= len) {
1554 seq += used;
1555 copied += used;
1556 offset += used;
1557 }
1558 /* If recv_actor drops the lock (e.g. TCP splice
1559 * receive) the skb pointer might be invalid when
1560 * getting here: tcp_collapse might have deleted it
1561 * while aggregating skbs from the socket queue.
1562 */
1563 skb = tcp_recv_skb(sk, seq - 1, &offset);
1564 if (!skb)
1565 break;
1566 /* TCP coalescing might have appended data to the skb.
1567 * Try to splice more frags
1568 */
1569 if (offset + 1 != skb->len)
1570 continue;
1571 }
1572 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1573 sk_eat_skb(sk, skb);
1574 ++seq;
1575 break;
1576 }
1577 sk_eat_skb(sk, skb);
1578 if (!desc->count)
1579 break;
1580 tp->copied_seq = seq;
1581 }
1582 tp->copied_seq = seq;
1583
1584 tcp_rcv_space_adjust(sk);
1585
1586 /* Clean up data we have read: This will do ACK frames. */
1587 if (copied > 0) {
1588 tcp_recv_skb(sk, seq, &offset);
1589 tcp_cleanup_rbuf(sk, copied);
1590 }
1591 return copied;
1592 }
1593 EXPORT_SYMBOL(tcp_read_sock);
1594
1595 int tcp_peek_len(struct socket *sock)
1596 {
1597 return tcp_inq(sock->sk);
1598 }
1599 EXPORT_SYMBOL(tcp_peek_len);
1600
1601 /*
1602 * This routine copies from a sock struct into the user buffer.
1603 *
1604 * Technical note: in 2.3 we work on _locked_ socket, so that
1605 * tricks with *seq access order and skb->users are not required.
1606 * Probably, code can be easily improved even more.
1607 */
1608
1609 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
1610 int flags, int *addr_len)
1611 {
1612 struct tcp_sock *tp = tcp_sk(sk);
1613 int copied = 0;
1614 u32 peek_seq;
1615 u32 *seq;
1616 unsigned long used;
1617 int err;
1618 int target; /* Read at least this many bytes */
1619 long timeo;
1620 struct task_struct *user_recv = NULL;
1621 struct sk_buff *skb, *last;
1622 u32 urg_hole = 0;
1623
1624 if (unlikely(flags & MSG_ERRQUEUE))
1625 return inet_recv_error(sk, msg, len, addr_len);
1626
1627 if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
1628 (sk->sk_state == TCP_ESTABLISHED))
1629 sk_busy_loop(sk, nonblock);
1630
1631 lock_sock(sk);
1632
1633 err = -ENOTCONN;
1634 if (sk->sk_state == TCP_LISTEN)
1635 goto out;
1636
1637 timeo = sock_rcvtimeo(sk, nonblock);
1638
1639 /* Urgent data needs to be handled specially. */
1640 if (flags & MSG_OOB)
1641 goto recv_urg;
1642
1643 if (unlikely(tp->repair)) {
1644 err = -EPERM;
1645 if (!(flags & MSG_PEEK))
1646 goto out;
1647
1648 if (tp->repair_queue == TCP_SEND_QUEUE)
1649 goto recv_sndq;
1650
1651 err = -EINVAL;
1652 if (tp->repair_queue == TCP_NO_QUEUE)
1653 goto out;
1654
1655 /* 'common' recv queue MSG_PEEK-ing */
1656 }
1657
1658 seq = &tp->copied_seq;
1659 if (flags & MSG_PEEK) {
1660 peek_seq = tp->copied_seq;
1661 seq = &peek_seq;
1662 }
1663
1664 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1665
1666 do {
1667 u32 offset;
1668
1669 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1670 if (tp->urg_data && tp->urg_seq == *seq) {
1671 if (copied)
1672 break;
1673 if (signal_pending(current)) {
1674 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1675 break;
1676 }
1677 }
1678
1679 /* Next get a buffer. */
1680
1681 last = skb_peek_tail(&sk->sk_receive_queue);
1682 skb_queue_walk(&sk->sk_receive_queue, skb) {
1683 last = skb;
1684 /* Now that we have two receive queues this
1685 * shouldn't happen.
1686 */
1687 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1688 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1689 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1690 flags))
1691 break;
1692
1693 offset = *seq - TCP_SKB_CB(skb)->seq;
1694 if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
1695 pr_err_once("%s: found a SYN, please report !\n", __func__);
1696 offset--;
1697 }
1698 if (offset < skb->len)
1699 goto found_ok_skb;
1700 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1701 goto found_fin_ok;
1702 WARN(!(flags & MSG_PEEK),
1703 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1704 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1705 }
1706
1707 /* Well, if we have backlog, try to process it now yet. */
1708
1709 if (copied >= target && !sk->sk_backlog.tail)
1710 break;
1711
1712 if (copied) {
1713 if (sk->sk_err ||
1714 sk->sk_state == TCP_CLOSE ||
1715 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1716 !timeo ||
1717 signal_pending(current))
1718 break;
1719 } else {
1720 if (sock_flag(sk, SOCK_DONE))
1721 break;
1722
1723 if (sk->sk_err) {
1724 copied = sock_error(sk);
1725 break;
1726 }
1727
1728 if (sk->sk_shutdown & RCV_SHUTDOWN)
1729 break;
1730
1731 if (sk->sk_state == TCP_CLOSE) {
1732 if (!sock_flag(sk, SOCK_DONE)) {
1733 /* This occurs when user tries to read
1734 * from never connected socket.
1735 */
1736 copied = -ENOTCONN;
1737 break;
1738 }
1739 break;
1740 }
1741
1742 if (!timeo) {
1743 copied = -EAGAIN;
1744 break;
1745 }
1746
1747 if (signal_pending(current)) {
1748 copied = sock_intr_errno(timeo);
1749 break;
1750 }
1751 }
1752
1753 tcp_cleanup_rbuf(sk, copied);
1754
1755 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1756 /* Install new reader */
1757 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1758 user_recv = current;
1759 tp->ucopy.task = user_recv;
1760 tp->ucopy.msg = msg;
1761 }
1762
1763 tp->ucopy.len = len;
1764
1765 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1766 !(flags & (MSG_PEEK | MSG_TRUNC)));
1767
1768 /* Ugly... If prequeue is not empty, we have to
1769 * process it before releasing socket, otherwise
1770 * order will be broken at second iteration.
1771 * More elegant solution is required!!!
1772 *
1773 * Look: we have the following (pseudo)queues:
1774 *
1775 * 1. packets in flight
1776 * 2. backlog
1777 * 3. prequeue
1778 * 4. receive_queue
1779 *
1780 * Each queue can be processed only if the next ones
1781 * are empty. At this point we have empty receive_queue.
1782 * But prequeue _can_ be not empty after 2nd iteration,
1783 * when we jumped to start of loop because backlog
1784 * processing added something to receive_queue.
1785 * We cannot release_sock(), because backlog contains
1786 * packets arrived _after_ prequeued ones.
1787 *
1788 * Shortly, algorithm is clear --- to process all
1789 * the queues in order. We could make it more directly,
1790 * requeueing packets from backlog to prequeue, if
1791 * is not empty. It is more elegant, but eats cycles,
1792 * unfortunately.
1793 */
1794 if (!skb_queue_empty(&tp->ucopy.prequeue))
1795 goto do_prequeue;
1796
1797 /* __ Set realtime policy in scheduler __ */
1798 }
1799
1800 if (copied >= target) {
1801 /* Do not sleep, just process backlog. */
1802 release_sock(sk);
1803 lock_sock(sk);
1804 } else {
1805 sk_wait_data(sk, &timeo, last);
1806 }
1807
1808 if (user_recv) {
1809 int chunk;
1810
1811 /* __ Restore normal policy in scheduler __ */
1812
1813 chunk = len - tp->ucopy.len;
1814 if (chunk != 0) {
1815 NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1816 len -= chunk;
1817 copied += chunk;
1818 }
1819
1820 if (tp->rcv_nxt == tp->copied_seq &&
1821 !skb_queue_empty(&tp->ucopy.prequeue)) {
1822 do_prequeue:
1823 tcp_prequeue_process(sk);
1824
1825 chunk = len - tp->ucopy.len;
1826 if (chunk != 0) {
1827 NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1828 len -= chunk;
1829 copied += chunk;
1830 }
1831 }
1832 }
1833 if ((flags & MSG_PEEK) &&
1834 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1835 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
1836 current->comm,
1837 task_pid_nr(current));
1838 peek_seq = tp->copied_seq;
1839 }
1840 continue;
1841
1842 found_ok_skb:
1843 /* Ok so how much can we use? */
1844 used = skb->len - offset;
1845 if (len < used)
1846 used = len;
1847
1848 /* Do we have urgent data here? */
1849 if (tp->urg_data) {
1850 u32 urg_offset = tp->urg_seq - *seq;
1851 if (urg_offset < used) {
1852 if (!urg_offset) {
1853 if (!sock_flag(sk, SOCK_URGINLINE)) {
1854 ++*seq;
1855 urg_hole++;
1856 offset++;
1857 used--;
1858 if (!used)
1859 goto skip_copy;
1860 }
1861 } else
1862 used = urg_offset;
1863 }
1864 }
1865
1866 if (!(flags & MSG_TRUNC)) {
1867 err = skb_copy_datagram_msg(skb, offset, msg, used);
1868 if (err) {
1869 /* Exception. Bailout! */
1870 if (!copied)
1871 copied = -EFAULT;
1872 break;
1873 }
1874 }
1875
1876 *seq += used;
1877 copied += used;
1878 len -= used;
1879
1880 tcp_rcv_space_adjust(sk);
1881
1882 skip_copy:
1883 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1884 tp->urg_data = 0;
1885 tcp_fast_path_check(sk);
1886 }
1887 if (used + offset < skb->len)
1888 continue;
1889
1890 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1891 goto found_fin_ok;
1892 if (!(flags & MSG_PEEK))
1893 sk_eat_skb(sk, skb);
1894 continue;
1895
1896 found_fin_ok:
1897 /* Process the FIN. */
1898 ++*seq;
1899 if (!(flags & MSG_PEEK))
1900 sk_eat_skb(sk, skb);
1901 break;
1902 } while (len > 0);
1903
1904 if (user_recv) {
1905 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1906 int chunk;
1907
1908 tp->ucopy.len = copied > 0 ? len : 0;
1909
1910 tcp_prequeue_process(sk);
1911
1912 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1913 NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1914 len -= chunk;
1915 copied += chunk;
1916 }
1917 }
1918
1919 tp->ucopy.task = NULL;
1920 tp->ucopy.len = 0;
1921 }
1922
1923 /* According to UNIX98, msg_name/msg_namelen are ignored
1924 * on connected socket. I was just happy when found this 8) --ANK
1925 */
1926
1927 /* Clean up data we have read: This will do ACK frames. */
1928 tcp_cleanup_rbuf(sk, copied);
1929
1930 release_sock(sk);
1931 return copied;
1932
1933 out:
1934 release_sock(sk);
1935 return err;
1936
1937 recv_urg:
1938 err = tcp_recv_urg(sk, msg, len, flags);
1939 goto out;
1940
1941 recv_sndq:
1942 err = tcp_peek_sndq(sk, msg, len);
1943 goto out;
1944 }
1945 EXPORT_SYMBOL(tcp_recvmsg);
1946
1947 void tcp_set_state(struct sock *sk, int state)
1948 {
1949 int oldstate = sk->sk_state;
1950
1951 switch (state) {
1952 case TCP_ESTABLISHED:
1953 if (oldstate != TCP_ESTABLISHED)
1954 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1955 break;
1956
1957 case TCP_CLOSE:
1958 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1959 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1960
1961 sk->sk_prot->unhash(sk);
1962 if (inet_csk(sk)->icsk_bind_hash &&
1963 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1964 inet_put_port(sk);
1965 /* fall through */
1966 default:
1967 if (oldstate == TCP_ESTABLISHED)
1968 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1969 }
1970
1971 /* Change state AFTER socket is unhashed to avoid closed
1972 * socket sitting in hash tables.
1973 */
1974 sk_state_store(sk, state);
1975
1976 #ifdef STATE_TRACE
1977 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1978 #endif
1979 }
1980 EXPORT_SYMBOL_GPL(tcp_set_state);
1981
1982 /*
1983 * State processing on a close. This implements the state shift for
1984 * sending our FIN frame. Note that we only send a FIN for some
1985 * states. A shutdown() may have already sent the FIN, or we may be
1986 * closed.
1987 */
1988
1989 static const unsigned char new_state[16] = {
1990 /* current state: new state: action: */
1991 [0 /* (Invalid) */] = TCP_CLOSE,
1992 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1993 [TCP_SYN_SENT] = TCP_CLOSE,
1994 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1995 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
1996 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
1997 [TCP_TIME_WAIT] = TCP_CLOSE,
1998 [TCP_CLOSE] = TCP_CLOSE,
1999 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2000 [TCP_LAST_ACK] = TCP_LAST_ACK,
2001 [TCP_LISTEN] = TCP_CLOSE,
2002 [TCP_CLOSING] = TCP_CLOSING,
2003 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2004 };
2005
2006 static int tcp_close_state(struct sock *sk)
2007 {
2008 int next = (int)new_state[sk->sk_state];
2009 int ns = next & TCP_STATE_MASK;
2010
2011 tcp_set_state(sk, ns);
2012
2013 return next & TCP_ACTION_FIN;
2014 }
2015
2016 /*
2017 * Shutdown the sending side of a connection. Much like close except
2018 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
2019 */
2020
2021 void tcp_shutdown(struct sock *sk, int how)
2022 {
2023 /* We need to grab some memory, and put together a FIN,
2024 * and then put it into the queue to be sent.
2025 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
2026 */
2027 if (!(how & SEND_SHUTDOWN))
2028 return;
2029
2030 /* If we've already sent a FIN, or it's a closed state, skip this. */
2031 if ((1 << sk->sk_state) &
2032 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
2033 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
2034 /* Clear out any half completed packets. FIN if needed. */
2035 if (tcp_close_state(sk))
2036 tcp_send_fin(sk);
2037 }
2038 }
2039 EXPORT_SYMBOL(tcp_shutdown);
2040
2041 bool tcp_check_oom(struct sock *sk, int shift)
2042 {
2043 bool too_many_orphans, out_of_socket_memory;
2044
2045 too_many_orphans = tcp_too_many_orphans(sk, shift);
2046 out_of_socket_memory = tcp_out_of_memory(sk);
2047
2048 if (too_many_orphans)
2049 net_info_ratelimited("too many orphaned sockets\n");
2050 if (out_of_socket_memory)
2051 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
2052 return too_many_orphans || out_of_socket_memory;
2053 }
2054
2055 void tcp_close(struct sock *sk, long timeout)
2056 {
2057 struct sk_buff *skb;
2058 int data_was_unread = 0;
2059 int state;
2060
2061 lock_sock(sk);
2062 sk->sk_shutdown = SHUTDOWN_MASK;
2063
2064 if (sk->sk_state == TCP_LISTEN) {
2065 tcp_set_state(sk, TCP_CLOSE);
2066
2067 /* Special case. */
2068 inet_csk_listen_stop(sk);
2069
2070 goto adjudge_to_death;
2071 }
2072
2073 /* We need to flush the recv. buffs. We do this only on the
2074 * descriptor close, not protocol-sourced closes, because the
2075 * reader process may not have drained the data yet!
2076 */
2077 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2078 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
2079
2080 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2081 len--;
2082 data_was_unread += len;
2083 __kfree_skb(skb);
2084 }
2085
2086 sk_mem_reclaim(sk);
2087
2088 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2089 if (sk->sk_state == TCP_CLOSE)
2090 goto adjudge_to_death;
2091
2092 /* As outlined in RFC 2525, section 2.17, we send a RST here because
2093 * data was lost. To witness the awful effects of the old behavior of
2094 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2095 * GET in an FTP client, suspend the process, wait for the client to
2096 * advertise a zero window, then kill -9 the FTP client, wheee...
2097 * Note: timeout is always zero in such a case.
2098 */
2099 if (unlikely(tcp_sk(sk)->repair)) {
2100 sk->sk_prot->disconnect(sk, 0);
2101 } else if (data_was_unread) {
2102 /* Unread data was tossed, zap the connection. */
2103 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2104 tcp_set_state(sk, TCP_CLOSE);
2105 tcp_send_active_reset(sk, sk->sk_allocation);
2106 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2107 /* Check zero linger _after_ checking for unread data. */
2108 sk->sk_prot->disconnect(sk, 0);
2109 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2110 } else if (tcp_close_state(sk)) {
2111 /* We FIN if the application ate all the data before
2112 * zapping the connection.
2113 */
2114
2115 /* RED-PEN. Formally speaking, we have broken TCP state
2116 * machine. State transitions:
2117 *
2118 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2119 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2120 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2121 *
2122 * are legal only when FIN has been sent (i.e. in window),
2123 * rather than queued out of window. Purists blame.
2124 *
2125 * F.e. "RFC state" is ESTABLISHED,
2126 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2127 *
2128 * The visible declinations are that sometimes
2129 * we enter time-wait state, when it is not required really
2130 * (harmless), do not send active resets, when they are
2131 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2132 * they look as CLOSING or LAST_ACK for Linux)
2133 * Probably, I missed some more holelets.
2134 * --ANK
2135 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2136 * in a single packet! (May consider it later but will
2137 * probably need API support or TCP_CORK SYN-ACK until
2138 * data is written and socket is closed.)
2139 */
2140 tcp_send_fin(sk);
2141 }
2142
2143 sk_stream_wait_close(sk, timeout);
2144
2145 adjudge_to_death:
2146 state = sk->sk_state;
2147 sock_hold(sk);
2148 sock_orphan(sk);
2149
2150 /* It is the last release_sock in its life. It will remove backlog. */
2151 release_sock(sk);
2152
2153
2154 /* Now socket is owned by kernel and we acquire BH lock
2155 to finish close. No need to check for user refs.
2156 */
2157 local_bh_disable();
2158 bh_lock_sock(sk);
2159 WARN_ON(sock_owned_by_user(sk));
2160
2161 percpu_counter_inc(sk->sk_prot->orphan_count);
2162
2163 /* Have we already been destroyed by a softirq or backlog? */
2164 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2165 goto out;
2166
2167 /* This is a (useful) BSD violating of the RFC. There is a
2168 * problem with TCP as specified in that the other end could
2169 * keep a socket open forever with no application left this end.
2170 * We use a 1 minute timeout (about the same as BSD) then kill
2171 * our end. If they send after that then tough - BUT: long enough
2172 * that we won't make the old 4*rto = almost no time - whoops
2173 * reset mistake.
2174 *
2175 * Nope, it was not mistake. It is really desired behaviour
2176 * f.e. on http servers, when such sockets are useless, but
2177 * consume significant resources. Let's do it with special
2178 * linger2 option. --ANK
2179 */
2180
2181 if (sk->sk_state == TCP_FIN_WAIT2) {
2182 struct tcp_sock *tp = tcp_sk(sk);
2183 if (tp->linger2 < 0) {
2184 tcp_set_state(sk, TCP_CLOSE);
2185 tcp_send_active_reset(sk, GFP_ATOMIC);
2186 __NET_INC_STATS(sock_net(sk),
2187 LINUX_MIB_TCPABORTONLINGER);
2188 } else {
2189 const int tmo = tcp_fin_time(sk);
2190
2191 if (tmo > TCP_TIMEWAIT_LEN) {
2192 inet_csk_reset_keepalive_timer(sk,
2193 tmo - TCP_TIMEWAIT_LEN);
2194 } else {
2195 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2196 goto out;
2197 }
2198 }
2199 }
2200 if (sk->sk_state != TCP_CLOSE) {
2201 sk_mem_reclaim(sk);
2202 if (tcp_check_oom(sk, 0)) {
2203 tcp_set_state(sk, TCP_CLOSE);
2204 tcp_send_active_reset(sk, GFP_ATOMIC);
2205 __NET_INC_STATS(sock_net(sk),
2206 LINUX_MIB_TCPABORTONMEMORY);
2207 }
2208 }
2209
2210 if (sk->sk_state == TCP_CLOSE) {
2211 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2212 /* We could get here with a non-NULL req if the socket is
2213 * aborted (e.g., closed with unread data) before 3WHS
2214 * finishes.
2215 */
2216 if (req)
2217 reqsk_fastopen_remove(sk, req, false);
2218 inet_csk_destroy_sock(sk);
2219 }
2220 /* Otherwise, socket is reprieved until protocol close. */
2221
2222 out:
2223 bh_unlock_sock(sk);
2224 local_bh_enable();
2225 sock_put(sk);
2226 }
2227 EXPORT_SYMBOL(tcp_close);
2228
2229 /* These states need RST on ABORT according to RFC793 */
2230
2231 static inline bool tcp_need_reset(int state)
2232 {
2233 return (1 << state) &
2234 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2235 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2236 }
2237
2238 int tcp_disconnect(struct sock *sk, int flags)
2239 {
2240 struct inet_sock *inet = inet_sk(sk);
2241 struct inet_connection_sock *icsk = inet_csk(sk);
2242 struct tcp_sock *tp = tcp_sk(sk);
2243 int err = 0;
2244 int old_state = sk->sk_state;
2245
2246 if (old_state != TCP_CLOSE)
2247 tcp_set_state(sk, TCP_CLOSE);
2248
2249 /* ABORT function of RFC793 */
2250 if (old_state == TCP_LISTEN) {
2251 inet_csk_listen_stop(sk);
2252 } else if (unlikely(tp->repair)) {
2253 sk->sk_err = ECONNABORTED;
2254 } else if (tcp_need_reset(old_state) ||
2255 (tp->snd_nxt != tp->write_seq &&
2256 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2257 /* The last check adjusts for discrepancy of Linux wrt. RFC
2258 * states
2259 */
2260 tcp_send_active_reset(sk, gfp_any());
2261 sk->sk_err = ECONNRESET;
2262 } else if (old_state == TCP_SYN_SENT)
2263 sk->sk_err = ECONNRESET;
2264
2265 tcp_clear_xmit_timers(sk);
2266 __skb_queue_purge(&sk->sk_receive_queue);
2267 tcp_write_queue_purge(sk);
2268 skb_rbtree_purge(&tp->out_of_order_queue);
2269
2270 inet->inet_dport = 0;
2271
2272 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2273 inet_reset_saddr(sk);
2274
2275 sk->sk_shutdown = 0;
2276 sock_reset_flag(sk, SOCK_DONE);
2277 tp->srtt_us = 0;
2278 tp->write_seq += tp->max_window + 2;
2279 if (tp->write_seq == 0)
2280 tp->write_seq = 1;
2281 icsk->icsk_backoff = 0;
2282 tp->snd_cwnd = 2;
2283 icsk->icsk_probes_out = 0;
2284 tp->packets_out = 0;
2285 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2286 tp->snd_cwnd_cnt = 0;
2287 tp->window_clamp = 0;
2288 tcp_set_ca_state(sk, TCP_CA_Open);
2289 tcp_clear_retrans(tp);
2290 inet_csk_delack_init(sk);
2291 tcp_init_send_head(sk);
2292 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2293 __sk_dst_reset(sk);
2294
2295 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2296
2297 sk->sk_error_report(sk);
2298 return err;
2299 }
2300 EXPORT_SYMBOL(tcp_disconnect);
2301
2302 static inline bool tcp_can_repair_sock(const struct sock *sk)
2303 {
2304 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
2305 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
2306 }
2307
2308 static int tcp_repair_set_window(struct tcp_sock *tp, char __user *optbuf, int len)
2309 {
2310 struct tcp_repair_window opt;
2311
2312 if (!tp->repair)
2313 return -EPERM;
2314
2315 if (len != sizeof(opt))
2316 return -EINVAL;
2317
2318 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2319 return -EFAULT;
2320
2321 if (opt.max_window < opt.snd_wnd)
2322 return -EINVAL;
2323
2324 if (after(opt.snd_wl1, tp->rcv_nxt + opt.rcv_wnd))
2325 return -EINVAL;
2326
2327 if (after(opt.rcv_wup, tp->rcv_nxt))
2328 return -EINVAL;
2329
2330 tp->snd_wl1 = opt.snd_wl1;
2331 tp->snd_wnd = opt.snd_wnd;
2332 tp->max_window = opt.max_window;
2333
2334 tp->rcv_wnd = opt.rcv_wnd;
2335 tp->rcv_wup = opt.rcv_wup;
2336
2337 return 0;
2338 }
2339
2340 static int tcp_repair_options_est(struct tcp_sock *tp,
2341 struct tcp_repair_opt __user *optbuf, unsigned int len)
2342 {
2343 struct tcp_repair_opt opt;
2344
2345 while (len >= sizeof(opt)) {
2346 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2347 return -EFAULT;
2348
2349 optbuf++;
2350 len -= sizeof(opt);
2351
2352 switch (opt.opt_code) {
2353 case TCPOPT_MSS:
2354 tp->rx_opt.mss_clamp = opt.opt_val;
2355 break;
2356 case TCPOPT_WINDOW:
2357 {
2358 u16 snd_wscale = opt.opt_val & 0xFFFF;
2359 u16 rcv_wscale = opt.opt_val >> 16;
2360
2361 if (snd_wscale > 14 || rcv_wscale > 14)
2362 return -EFBIG;
2363
2364 tp->rx_opt.snd_wscale = snd_wscale;
2365 tp->rx_opt.rcv_wscale = rcv_wscale;
2366 tp->rx_opt.wscale_ok = 1;
2367 }
2368 break;
2369 case TCPOPT_SACK_PERM:
2370 if (opt.opt_val != 0)
2371 return -EINVAL;
2372
2373 tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2374 if (sysctl_tcp_fack)
2375 tcp_enable_fack(tp);
2376 break;
2377 case TCPOPT_TIMESTAMP:
2378 if (opt.opt_val != 0)
2379 return -EINVAL;
2380
2381 tp->rx_opt.tstamp_ok = 1;
2382 break;
2383 }
2384 }
2385
2386 return 0;
2387 }
2388
2389 /*
2390 * Socket option code for TCP.
2391 */
2392 static int do_tcp_setsockopt(struct sock *sk, int level,
2393 int optname, char __user *optval, unsigned int optlen)
2394 {
2395 struct tcp_sock *tp = tcp_sk(sk);
2396 struct inet_connection_sock *icsk = inet_csk(sk);
2397 struct net *net = sock_net(sk);
2398 int val;
2399 int err = 0;
2400
2401 /* These are data/string values, all the others are ints */
2402 switch (optname) {
2403 case TCP_CONGESTION: {
2404 char name[TCP_CA_NAME_MAX];
2405
2406 if (optlen < 1)
2407 return -EINVAL;
2408
2409 val = strncpy_from_user(name, optval,
2410 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2411 if (val < 0)
2412 return -EFAULT;
2413 name[val] = 0;
2414
2415 lock_sock(sk);
2416 err = tcp_set_congestion_control(sk, name);
2417 release_sock(sk);
2418 return err;
2419 }
2420 default:
2421 /* fallthru */
2422 break;
2423 }
2424
2425 if (optlen < sizeof(int))
2426 return -EINVAL;
2427
2428 if (get_user(val, (int __user *)optval))
2429 return -EFAULT;
2430
2431 lock_sock(sk);
2432
2433 switch (optname) {
2434 case TCP_MAXSEG:
2435 /* Values greater than interface MTU won't take effect. However
2436 * at the point when this call is done we typically don't yet
2437 * know which interface is going to be used */
2438 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2439 err = -EINVAL;
2440 break;
2441 }
2442 tp->rx_opt.user_mss = val;
2443 break;
2444
2445 case TCP_NODELAY:
2446 if (val) {
2447 /* TCP_NODELAY is weaker than TCP_CORK, so that
2448 * this option on corked socket is remembered, but
2449 * it is not activated until cork is cleared.
2450 *
2451 * However, when TCP_NODELAY is set we make
2452 * an explicit push, which overrides even TCP_CORK
2453 * for currently queued segments.
2454 */
2455 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2456 tcp_push_pending_frames(sk);
2457 } else {
2458 tp->nonagle &= ~TCP_NAGLE_OFF;
2459 }
2460 break;
2461
2462 case TCP_THIN_LINEAR_TIMEOUTS:
2463 if (val < 0 || val > 1)
2464 err = -EINVAL;
2465 else
2466 tp->thin_lto = val;
2467 break;
2468
2469 case TCP_THIN_DUPACK:
2470 if (val < 0 || val > 1)
2471 err = -EINVAL;
2472 else {
2473 tp->thin_dupack = val;
2474 if (tp->thin_dupack)
2475 tcp_disable_early_retrans(tp);
2476 }
2477 break;
2478
2479 case TCP_REPAIR:
2480 if (!tcp_can_repair_sock(sk))
2481 err = -EPERM;
2482 else if (val == 1) {
2483 tp->repair = 1;
2484 sk->sk_reuse = SK_FORCE_REUSE;
2485 tp->repair_queue = TCP_NO_QUEUE;
2486 } else if (val == 0) {
2487 tp->repair = 0;
2488 sk->sk_reuse = SK_NO_REUSE;
2489 tcp_send_window_probe(sk);
2490 } else
2491 err = -EINVAL;
2492
2493 break;
2494
2495 case TCP_REPAIR_QUEUE:
2496 if (!tp->repair)
2497 err = -EPERM;
2498 else if (val < TCP_QUEUES_NR)
2499 tp->repair_queue = val;
2500 else
2501 err = -EINVAL;
2502 break;
2503
2504 case TCP_QUEUE_SEQ:
2505 if (sk->sk_state != TCP_CLOSE)
2506 err = -EPERM;
2507 else if (tp->repair_queue == TCP_SEND_QUEUE)
2508 tp->write_seq = val;
2509 else if (tp->repair_queue == TCP_RECV_QUEUE)
2510 tp->rcv_nxt = val;
2511 else
2512 err = -EINVAL;
2513 break;
2514
2515 case TCP_REPAIR_OPTIONS:
2516 if (!tp->repair)
2517 err = -EINVAL;
2518 else if (sk->sk_state == TCP_ESTABLISHED)
2519 err = tcp_repair_options_est(tp,
2520 (struct tcp_repair_opt __user *)optval,
2521 optlen);
2522 else
2523 err = -EPERM;
2524 break;
2525
2526 case TCP_CORK:
2527 /* When set indicates to always queue non-full frames.
2528 * Later the user clears this option and we transmit
2529 * any pending partial frames in the queue. This is
2530 * meant to be used alongside sendfile() to get properly
2531 * filled frames when the user (for example) must write
2532 * out headers with a write() call first and then use
2533 * sendfile to send out the data parts.
2534 *
2535 * TCP_CORK can be set together with TCP_NODELAY and it is
2536 * stronger than TCP_NODELAY.
2537 */
2538 if (val) {
2539 tp->nonagle |= TCP_NAGLE_CORK;
2540 } else {
2541 tp->nonagle &= ~TCP_NAGLE_CORK;
2542 if (tp->nonagle&TCP_NAGLE_OFF)
2543 tp->nonagle |= TCP_NAGLE_PUSH;
2544 tcp_push_pending_frames(sk);
2545 }
2546 break;
2547
2548 case TCP_KEEPIDLE:
2549 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2550 err = -EINVAL;
2551 else {
2552 tp->keepalive_time = val * HZ;
2553 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2554 !((1 << sk->sk_state) &
2555 (TCPF_CLOSE | TCPF_LISTEN))) {
2556 u32 elapsed = keepalive_time_elapsed(tp);
2557 if (tp->keepalive_time > elapsed)
2558 elapsed = tp->keepalive_time - elapsed;
2559 else
2560 elapsed = 0;
2561 inet_csk_reset_keepalive_timer(sk, elapsed);
2562 }
2563 }
2564 break;
2565 case TCP_KEEPINTVL:
2566 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2567 err = -EINVAL;
2568 else
2569 tp->keepalive_intvl = val * HZ;
2570 break;
2571 case TCP_KEEPCNT:
2572 if (val < 1 || val > MAX_TCP_KEEPCNT)
2573 err = -EINVAL;
2574 else
2575 tp->keepalive_probes = val;
2576 break;
2577 case TCP_SYNCNT:
2578 if (val < 1 || val > MAX_TCP_SYNCNT)
2579 err = -EINVAL;
2580 else
2581 icsk->icsk_syn_retries = val;
2582 break;
2583
2584 case TCP_SAVE_SYN:
2585 if (val < 0 || val > 1)
2586 err = -EINVAL;
2587 else
2588 tp->save_syn = val;
2589 break;
2590
2591 case TCP_LINGER2:
2592 if (val < 0)
2593 tp->linger2 = -1;
2594 else if (val > net->ipv4.sysctl_tcp_fin_timeout / HZ)
2595 tp->linger2 = 0;
2596 else
2597 tp->linger2 = val * HZ;
2598 break;
2599
2600 case TCP_DEFER_ACCEPT:
2601 /* Translate value in seconds to number of retransmits */
2602 icsk->icsk_accept_queue.rskq_defer_accept =
2603 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2604 TCP_RTO_MAX / HZ);
2605 break;
2606
2607 case TCP_WINDOW_CLAMP:
2608 if (!val) {
2609 if (sk->sk_state != TCP_CLOSE) {
2610 err = -EINVAL;
2611 break;
2612 }
2613 tp->window_clamp = 0;
2614 } else
2615 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2616 SOCK_MIN_RCVBUF / 2 : val;
2617 break;
2618
2619 case TCP_QUICKACK:
2620 if (!val) {
2621 icsk->icsk_ack.pingpong = 1;
2622 } else {
2623 icsk->icsk_ack.pingpong = 0;
2624 if ((1 << sk->sk_state) &
2625 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2626 inet_csk_ack_scheduled(sk)) {
2627 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2628 tcp_cleanup_rbuf(sk, 1);
2629 if (!(val & 1))
2630 icsk->icsk_ack.pingpong = 1;
2631 }
2632 }
2633 break;
2634
2635 #ifdef CONFIG_TCP_MD5SIG
2636 case TCP_MD5SIG:
2637 /* Read the IP->Key mappings from userspace */
2638 err = tp->af_specific->md5_parse(sk, optval, optlen);
2639 break;
2640 #endif
2641 case TCP_USER_TIMEOUT:
2642 /* Cap the max time in ms TCP will retry or probe the window
2643 * before giving up and aborting (ETIMEDOUT) a connection.
2644 */
2645 if (val < 0)
2646 err = -EINVAL;
2647 else
2648 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2649 break;
2650
2651 case TCP_FASTOPEN:
2652 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2653 TCPF_LISTEN))) {
2654 tcp_fastopen_init_key_once(true);
2655
2656 fastopen_queue_tune(sk, val);
2657 } else {
2658 err = -EINVAL;
2659 }
2660 break;
2661 case TCP_TIMESTAMP:
2662 if (!tp->repair)
2663 err = -EPERM;
2664 else
2665 tp->tsoffset = val - tcp_time_stamp;
2666 break;
2667 case TCP_REPAIR_WINDOW:
2668 err = tcp_repair_set_window(tp, optval, optlen);
2669 break;
2670 case TCP_NOTSENT_LOWAT:
2671 tp->notsent_lowat = val;
2672 sk->sk_write_space(sk);
2673 break;
2674 default:
2675 err = -ENOPROTOOPT;
2676 break;
2677 }
2678
2679 release_sock(sk);
2680 return err;
2681 }
2682
2683 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2684 unsigned int optlen)
2685 {
2686 const struct inet_connection_sock *icsk = inet_csk(sk);
2687
2688 if (level != SOL_TCP)
2689 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2690 optval, optlen);
2691 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2692 }
2693 EXPORT_SYMBOL(tcp_setsockopt);
2694
2695 #ifdef CONFIG_COMPAT
2696 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2697 char __user *optval, unsigned int optlen)
2698 {
2699 if (level != SOL_TCP)
2700 return inet_csk_compat_setsockopt(sk, level, optname,
2701 optval, optlen);
2702 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2703 }
2704 EXPORT_SYMBOL(compat_tcp_setsockopt);
2705 #endif
2706
2707 /* Return information about state of tcp endpoint in API format. */
2708 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2709 {
2710 const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
2711 const struct inet_connection_sock *icsk = inet_csk(sk);
2712 u32 now = tcp_time_stamp, intv;
2713 unsigned int start;
2714 int notsent_bytes;
2715 u64 rate64;
2716 u32 rate;
2717
2718 memset(info, 0, sizeof(*info));
2719 if (sk->sk_type != SOCK_STREAM)
2720 return;
2721
2722 info->tcpi_state = sk_state_load(sk);
2723
2724 info->tcpi_ca_state = icsk->icsk_ca_state;
2725 info->tcpi_retransmits = icsk->icsk_retransmits;
2726 info->tcpi_probes = icsk->icsk_probes_out;
2727 info->tcpi_backoff = icsk->icsk_backoff;
2728
2729 if (tp->rx_opt.tstamp_ok)
2730 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2731 if (tcp_is_sack(tp))
2732 info->tcpi_options |= TCPI_OPT_SACK;
2733 if (tp->rx_opt.wscale_ok) {
2734 info->tcpi_options |= TCPI_OPT_WSCALE;
2735 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2736 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2737 }
2738
2739 if (tp->ecn_flags & TCP_ECN_OK)
2740 info->tcpi_options |= TCPI_OPT_ECN;
2741 if (tp->ecn_flags & TCP_ECN_SEEN)
2742 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2743 if (tp->syn_data_acked)
2744 info->tcpi_options |= TCPI_OPT_SYN_DATA;
2745
2746 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2747 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2748 info->tcpi_snd_mss = tp->mss_cache;
2749 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2750
2751 if (info->tcpi_state == TCP_LISTEN) {
2752 info->tcpi_unacked = sk->sk_ack_backlog;
2753 info->tcpi_sacked = sk->sk_max_ack_backlog;
2754 } else {
2755 info->tcpi_unacked = tp->packets_out;
2756 info->tcpi_sacked = tp->sacked_out;
2757 }
2758 info->tcpi_lost = tp->lost_out;
2759 info->tcpi_retrans = tp->retrans_out;
2760 info->tcpi_fackets = tp->fackets_out;
2761
2762 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2763 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2764 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2765
2766 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2767 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2768 info->tcpi_rtt = tp->srtt_us >> 3;
2769 info->tcpi_rttvar = tp->mdev_us >> 2;
2770 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2771 info->tcpi_snd_cwnd = tp->snd_cwnd;
2772 info->tcpi_advmss = tp->advmss;
2773 info->tcpi_reordering = tp->reordering;
2774
2775 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2776 info->tcpi_rcv_space = tp->rcvq_space.space;
2777
2778 info->tcpi_total_retrans = tp->total_retrans;
2779
2780 rate = READ_ONCE(sk->sk_pacing_rate);
2781 rate64 = rate != ~0U ? rate : ~0ULL;
2782 put_unaligned(rate64, &info->tcpi_pacing_rate);
2783
2784 rate = READ_ONCE(sk->sk_max_pacing_rate);
2785 rate64 = rate != ~0U ? rate : ~0ULL;
2786 put_unaligned(rate64, &info->tcpi_max_pacing_rate);
2787
2788 do {
2789 start = u64_stats_fetch_begin_irq(&tp->syncp);
2790 put_unaligned(tp->bytes_acked, &info->tcpi_bytes_acked);
2791 put_unaligned(tp->bytes_received, &info->tcpi_bytes_received);
2792 } while (u64_stats_fetch_retry_irq(&tp->syncp, start));
2793 info->tcpi_segs_out = tp->segs_out;
2794 info->tcpi_segs_in = tp->segs_in;
2795
2796 notsent_bytes = READ_ONCE(tp->write_seq) - READ_ONCE(tp->snd_nxt);
2797 info->tcpi_notsent_bytes = max(0, notsent_bytes);
2798
2799 info->tcpi_min_rtt = tcp_min_rtt(tp);
2800 info->tcpi_data_segs_in = tp->data_segs_in;
2801 info->tcpi_data_segs_out = tp->data_segs_out;
2802
2803 info->tcpi_delivery_rate_app_limited = tp->rate_app_limited ? 1 : 0;
2804 rate = READ_ONCE(tp->rate_delivered);
2805 intv = READ_ONCE(tp->rate_interval_us);
2806 if (rate && intv) {
2807 rate64 = (u64)rate * tp->mss_cache * USEC_PER_SEC;
2808 do_div(rate64, intv);
2809 put_unaligned(rate64, &info->tcpi_delivery_rate);
2810 }
2811 }
2812 EXPORT_SYMBOL_GPL(tcp_get_info);
2813
2814 static int do_tcp_getsockopt(struct sock *sk, int level,
2815 int optname, char __user *optval, int __user *optlen)
2816 {
2817 struct inet_connection_sock *icsk = inet_csk(sk);
2818 struct tcp_sock *tp = tcp_sk(sk);
2819 struct net *net = sock_net(sk);
2820 int val, len;
2821
2822 if (get_user(len, optlen))
2823 return -EFAULT;
2824
2825 len = min_t(unsigned int, len, sizeof(int));
2826
2827 if (len < 0)
2828 return -EINVAL;
2829
2830 switch (optname) {
2831 case TCP_MAXSEG:
2832 val = tp->mss_cache;
2833 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2834 val = tp->rx_opt.user_mss;
2835 if (tp->repair)
2836 val = tp->rx_opt.mss_clamp;
2837 break;
2838 case TCP_NODELAY:
2839 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2840 break;
2841 case TCP_CORK:
2842 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2843 break;
2844 case TCP_KEEPIDLE:
2845 val = keepalive_time_when(tp) / HZ;
2846 break;
2847 case TCP_KEEPINTVL:
2848 val = keepalive_intvl_when(tp) / HZ;
2849 break;
2850 case TCP_KEEPCNT:
2851 val = keepalive_probes(tp);
2852 break;
2853 case TCP_SYNCNT:
2854 val = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries;
2855 break;
2856 case TCP_LINGER2:
2857 val = tp->linger2;
2858 if (val >= 0)
2859 val = (val ? : net->ipv4.sysctl_tcp_fin_timeout) / HZ;
2860 break;
2861 case TCP_DEFER_ACCEPT:
2862 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2863 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2864 break;
2865 case TCP_WINDOW_CLAMP:
2866 val = tp->window_clamp;
2867 break;
2868 case TCP_INFO: {
2869 struct tcp_info info;
2870
2871 if (get_user(len, optlen))
2872 return -EFAULT;
2873
2874 tcp_get_info(sk, &info);
2875
2876 len = min_t(unsigned int, len, sizeof(info));
2877 if (put_user(len, optlen))
2878 return -EFAULT;
2879 if (copy_to_user(optval, &info, len))
2880 return -EFAULT;
2881 return 0;
2882 }
2883 case TCP_CC_INFO: {
2884 const struct tcp_congestion_ops *ca_ops;
2885 union tcp_cc_info info;
2886 size_t sz = 0;
2887 int attr;
2888
2889 if (get_user(len, optlen))
2890 return -EFAULT;
2891
2892 ca_ops = icsk->icsk_ca_ops;
2893 if (ca_ops && ca_ops->get_info)
2894 sz = ca_ops->get_info(sk, ~0U, &attr, &info);
2895
2896 len = min_t(unsigned int, len, sz);
2897 if (put_user(len, optlen))
2898 return -EFAULT;
2899 if (copy_to_user(optval, &info, len))
2900 return -EFAULT;
2901 return 0;
2902 }
2903 case TCP_QUICKACK:
2904 val = !icsk->icsk_ack.pingpong;
2905 break;
2906
2907 case TCP_CONGESTION:
2908 if (get_user(len, optlen))
2909 return -EFAULT;
2910 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2911 if (put_user(len, optlen))
2912 return -EFAULT;
2913 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2914 return -EFAULT;
2915 return 0;
2916
2917 case TCP_THIN_LINEAR_TIMEOUTS:
2918 val = tp->thin_lto;
2919 break;
2920 case TCP_THIN_DUPACK:
2921 val = tp->thin_dupack;
2922 break;
2923
2924 case TCP_REPAIR:
2925 val = tp->repair;
2926 break;
2927
2928 case TCP_REPAIR_QUEUE:
2929 if (tp->repair)
2930 val = tp->repair_queue;
2931 else
2932 return -EINVAL;
2933 break;
2934
2935 case TCP_REPAIR_WINDOW: {
2936 struct tcp_repair_window opt;
2937
2938 if (get_user(len, optlen))
2939 return -EFAULT;
2940
2941 if (len != sizeof(opt))
2942 return -EINVAL;
2943
2944 if (!tp->repair)
2945 return -EPERM;
2946
2947 opt.snd_wl1 = tp->snd_wl1;
2948 opt.snd_wnd = tp->snd_wnd;
2949 opt.max_window = tp->max_window;
2950 opt.rcv_wnd = tp->rcv_wnd;
2951 opt.rcv_wup = tp->rcv_wup;
2952
2953 if (copy_to_user(optval, &opt, len))
2954 return -EFAULT;
2955 return 0;
2956 }
2957 case TCP_QUEUE_SEQ:
2958 if (tp->repair_queue == TCP_SEND_QUEUE)
2959 val = tp->write_seq;
2960 else if (tp->repair_queue == TCP_RECV_QUEUE)
2961 val = tp->rcv_nxt;
2962 else
2963 return -EINVAL;
2964 break;
2965
2966 case TCP_USER_TIMEOUT:
2967 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2968 break;
2969
2970 case TCP_FASTOPEN:
2971 val = icsk->icsk_accept_queue.fastopenq.max_qlen;
2972 break;
2973
2974 case TCP_TIMESTAMP:
2975 val = tcp_time_stamp + tp->tsoffset;
2976 break;
2977 case TCP_NOTSENT_LOWAT:
2978 val = tp->notsent_lowat;
2979 break;
2980 case TCP_SAVE_SYN:
2981 val = tp->save_syn;
2982 break;
2983 case TCP_SAVED_SYN: {
2984 if (get_user(len, optlen))
2985 return -EFAULT;
2986
2987 lock_sock(sk);
2988 if (tp->saved_syn) {
2989 if (len < tp->saved_syn[0]) {
2990 if (put_user(tp->saved_syn[0], optlen)) {
2991 release_sock(sk);
2992 return -EFAULT;
2993 }
2994 release_sock(sk);
2995 return -EINVAL;
2996 }
2997 len = tp->saved_syn[0];
2998 if (put_user(len, optlen)) {
2999 release_sock(sk);
3000 return -EFAULT;
3001 }
3002 if (copy_to_user(optval, tp->saved_syn + 1, len)) {
3003 release_sock(sk);
3004 return -EFAULT;
3005 }
3006 tcp_saved_syn_free(tp);
3007 release_sock(sk);
3008 } else {
3009 release_sock(sk);
3010 len = 0;
3011 if (put_user(len, optlen))
3012 return -EFAULT;
3013 }
3014 return 0;
3015 }
3016 default:
3017 return -ENOPROTOOPT;
3018 }
3019
3020 if (put_user(len, optlen))
3021 return -EFAULT;
3022 if (copy_to_user(optval, &val, len))
3023 return -EFAULT;
3024 return 0;
3025 }
3026
3027 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
3028 int __user *optlen)
3029 {
3030 struct inet_connection_sock *icsk = inet_csk(sk);
3031
3032 if (level != SOL_TCP)
3033 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
3034 optval, optlen);
3035 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
3036 }
3037 EXPORT_SYMBOL(tcp_getsockopt);
3038
3039 #ifdef CONFIG_COMPAT
3040 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
3041 char __user *optval, int __user *optlen)
3042 {
3043 if (level != SOL_TCP)
3044 return inet_csk_compat_getsockopt(sk, level, optname,
3045 optval, optlen);
3046 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
3047 }
3048 EXPORT_SYMBOL(compat_tcp_getsockopt);
3049 #endif
3050
3051 #ifdef CONFIG_TCP_MD5SIG
3052 static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
3053 static DEFINE_MUTEX(tcp_md5sig_mutex);
3054 static bool tcp_md5sig_pool_populated = false;
3055
3056 static void __tcp_alloc_md5sig_pool(void)
3057 {
3058 struct crypto_ahash *hash;
3059 int cpu;
3060
3061 hash = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
3062 if (IS_ERR(hash))
3063 return;
3064
3065 for_each_possible_cpu(cpu) {
3066 void *scratch = per_cpu(tcp_md5sig_pool, cpu).scratch;
3067 struct ahash_request *req;
3068
3069 if (!scratch) {
3070 scratch = kmalloc_node(sizeof(union tcp_md5sum_block) +
3071 sizeof(struct tcphdr),
3072 GFP_KERNEL,
3073 cpu_to_node(cpu));
3074 if (!scratch)
3075 return;
3076 per_cpu(tcp_md5sig_pool, cpu).scratch = scratch;
3077 }
3078 if (per_cpu(tcp_md5sig_pool, cpu).md5_req)
3079 continue;
3080
3081 req = ahash_request_alloc(hash, GFP_KERNEL);
3082 if (!req)
3083 return;
3084
3085 ahash_request_set_callback(req, 0, NULL, NULL);
3086
3087 per_cpu(tcp_md5sig_pool, cpu).md5_req = req;
3088 }
3089 /* before setting tcp_md5sig_pool_populated, we must commit all writes
3090 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
3091 */
3092 smp_wmb();
3093 tcp_md5sig_pool_populated = true;
3094 }
3095
3096 bool tcp_alloc_md5sig_pool(void)
3097 {
3098 if (unlikely(!tcp_md5sig_pool_populated)) {
3099 mutex_lock(&tcp_md5sig_mutex);
3100
3101 if (!tcp_md5sig_pool_populated)
3102 __tcp_alloc_md5sig_pool();
3103
3104 mutex_unlock(&tcp_md5sig_mutex);
3105 }
3106 return tcp_md5sig_pool_populated;
3107 }
3108 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
3109
3110
3111 /**
3112 * tcp_get_md5sig_pool - get md5sig_pool for this user
3113 *
3114 * We use percpu structure, so if we succeed, we exit with preemption
3115 * and BH disabled, to make sure another thread or softirq handling
3116 * wont try to get same context.
3117 */
3118 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
3119 {
3120 local_bh_disable();
3121
3122 if (tcp_md5sig_pool_populated) {
3123 /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
3124 smp_rmb();
3125 return this_cpu_ptr(&tcp_md5sig_pool);
3126 }
3127 local_bh_enable();
3128 return NULL;
3129 }
3130 EXPORT_SYMBOL(tcp_get_md5sig_pool);
3131
3132 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3133 const struct sk_buff *skb, unsigned int header_len)
3134 {
3135 struct scatterlist sg;
3136 const struct tcphdr *tp = tcp_hdr(skb);
3137 struct ahash_request *req = hp->md5_req;
3138 unsigned int i;
3139 const unsigned int head_data_len = skb_headlen(skb) > header_len ?
3140 skb_headlen(skb) - header_len : 0;
3141 const struct skb_shared_info *shi = skb_shinfo(skb);
3142 struct sk_buff *frag_iter;
3143
3144 sg_init_table(&sg, 1);
3145
3146 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3147 ahash_request_set_crypt(req, &sg, NULL, head_data_len);
3148 if (crypto_ahash_update(req))
3149 return 1;
3150
3151 for (i = 0; i < shi->nr_frags; ++i) {
3152 const struct skb_frag_struct *f = &shi->frags[i];
3153 unsigned int offset = f->page_offset;
3154 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
3155
3156 sg_set_page(&sg, page, skb_frag_size(f),
3157 offset_in_page(offset));
3158 ahash_request_set_crypt(req, &sg, NULL, skb_frag_size(f));
3159 if (crypto_ahash_update(req))
3160 return 1;
3161 }
3162
3163 skb_walk_frags(skb, frag_iter)
3164 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3165 return 1;
3166
3167 return 0;
3168 }
3169 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3170
3171 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3172 {
3173 struct scatterlist sg;
3174
3175 sg_init_one(&sg, key->key, key->keylen);
3176 ahash_request_set_crypt(hp->md5_req, &sg, NULL, key->keylen);
3177 return crypto_ahash_update(hp->md5_req);
3178 }
3179 EXPORT_SYMBOL(tcp_md5_hash_key);
3180
3181 #endif
3182
3183 void tcp_done(struct sock *sk)
3184 {
3185 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
3186
3187 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3188 TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3189
3190 tcp_set_state(sk, TCP_CLOSE);
3191 tcp_clear_xmit_timers(sk);
3192 if (req)
3193 reqsk_fastopen_remove(sk, req, false);
3194
3195 sk->sk_shutdown = SHUTDOWN_MASK;
3196
3197 if (!sock_flag(sk, SOCK_DEAD))
3198 sk->sk_state_change(sk);
3199 else
3200 inet_csk_destroy_sock(sk);
3201 }
3202 EXPORT_SYMBOL_GPL(tcp_done);
3203
3204 int tcp_abort(struct sock *sk, int err)
3205 {
3206 if (!sk_fullsock(sk)) {
3207 if (sk->sk_state == TCP_NEW_SYN_RECV) {
3208 struct request_sock *req = inet_reqsk(sk);
3209
3210 local_bh_disable();
3211 inet_csk_reqsk_queue_drop_and_put(req->rsk_listener,
3212 req);
3213 local_bh_enable();
3214 return 0;
3215 }
3216 return -EOPNOTSUPP;
3217 }
3218
3219 /* Don't race with userspace socket closes such as tcp_close. */
3220 lock_sock(sk);
3221
3222 if (sk->sk_state == TCP_LISTEN) {
3223 tcp_set_state(sk, TCP_CLOSE);
3224 inet_csk_listen_stop(sk);
3225 }
3226
3227 /* Don't race with BH socket closes such as inet_csk_listen_stop. */
3228 local_bh_disable();
3229 bh_lock_sock(sk);
3230
3231 if (!sock_flag(sk, SOCK_DEAD)) {
3232 sk->sk_err = err;
3233 /* This barrier is coupled with smp_rmb() in tcp_poll() */
3234 smp_wmb();
3235 sk->sk_error_report(sk);
3236 if (tcp_need_reset(sk->sk_state))
3237 tcp_send_active_reset(sk, GFP_ATOMIC);
3238 tcp_done(sk);
3239 }
3240
3241 bh_unlock_sock(sk);
3242 local_bh_enable();
3243 release_sock(sk);
3244 return 0;
3245 }
3246 EXPORT_SYMBOL_GPL(tcp_abort);
3247
3248 extern struct tcp_congestion_ops tcp_reno;
3249
3250 static __initdata unsigned long thash_entries;
3251 static int __init set_thash_entries(char *str)
3252 {
3253 ssize_t ret;
3254
3255 if (!str)
3256 return 0;
3257
3258 ret = kstrtoul(str, 0, &thash_entries);
3259 if (ret)
3260 return 0;
3261
3262 return 1;
3263 }
3264 __setup("thash_entries=", set_thash_entries);
3265
3266 static void __init tcp_init_mem(void)
3267 {
3268 unsigned long limit = nr_free_buffer_pages() / 16;
3269
3270 limit = max(limit, 128UL);
3271 sysctl_tcp_mem[0] = limit / 4 * 3; /* 4.68 % */
3272 sysctl_tcp_mem[1] = limit; /* 6.25 % */
3273 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; /* 9.37 % */
3274 }
3275
3276 void __init tcp_init(void)
3277 {
3278 int max_rshare, max_wshare, cnt;
3279 unsigned long limit;
3280 unsigned int i;
3281
3282 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) >
3283 FIELD_SIZEOF(struct sk_buff, cb));
3284
3285 percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
3286 percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3287 tcp_hashinfo.bind_bucket_cachep =
3288 kmem_cache_create("tcp_bind_bucket",
3289 sizeof(struct inet_bind_bucket), 0,
3290 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3291
3292 /* Size and allocate the main established and bind bucket
3293 * hash tables.
3294 *
3295 * The methodology is similar to that of the buffer cache.
3296 */
3297 tcp_hashinfo.ehash =
3298 alloc_large_system_hash("TCP established",
3299 sizeof(struct inet_ehash_bucket),
3300 thash_entries,
3301 17, /* one slot per 128 KB of memory */
3302 0,
3303 NULL,
3304 &tcp_hashinfo.ehash_mask,
3305 0,
3306 thash_entries ? 0 : 512 * 1024);
3307 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3308 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3309
3310 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3311 panic("TCP: failed to alloc ehash_locks");
3312 tcp_hashinfo.bhash =
3313 alloc_large_system_hash("TCP bind",
3314 sizeof(struct inet_bind_hashbucket),
3315 tcp_hashinfo.ehash_mask + 1,
3316 17, /* one slot per 128 KB of memory */
3317 0,
3318 &tcp_hashinfo.bhash_size,
3319 NULL,
3320 0,
3321 64 * 1024);
3322 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3323 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3324 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3325 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3326 }
3327
3328
3329 cnt = tcp_hashinfo.ehash_mask + 1;
3330
3331 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3332 sysctl_tcp_max_orphans = cnt / 2;
3333 sysctl_max_syn_backlog = max(128, cnt / 256);
3334
3335 tcp_init_mem();
3336 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3337 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3338 max_wshare = min(4UL*1024*1024, limit);
3339 max_rshare = min(6UL*1024*1024, limit);
3340
3341 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3342 sysctl_tcp_wmem[1] = 16*1024;
3343 sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3344
3345 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3346 sysctl_tcp_rmem[1] = 87380;
3347 sysctl_tcp_rmem[2] = max(87380, max_rshare);
3348
3349 pr_info("Hash tables configured (established %u bind %u)\n",
3350 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3351
3352 tcp_metrics_init();
3353 BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
3354 tcp_tasklet_init();
3355 }