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netlink: make nlmsg_end() and genlmsg_end() void
[deliverable/linux.git] / net / ipv4 / tcp.c
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Mark Evans, <evansmp@uhura.aston.ac.uk>
11 * Corey Minyard <wf-rch!minyard@relay.EU.net>
12 * Florian La Roche, <flla@stud.uni-sb.de>
13 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
14 * Linus Torvalds, <torvalds@cs.helsinki.fi>
15 * Alan Cox, <gw4pts@gw4pts.ampr.org>
16 * Matthew Dillon, <dillon@apollo.west.oic.com>
17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
18 * Jorge Cwik, <jorge@laser.satlink.net>
19 *
20 * Fixes:
21 * Alan Cox : Numerous verify_area() calls
22 * Alan Cox : Set the ACK bit on a reset
23 * Alan Cox : Stopped it crashing if it closed while
24 * sk->inuse=1 and was trying to connect
25 * (tcp_err()).
26 * Alan Cox : All icmp error handling was broken
27 * pointers passed where wrong and the
28 * socket was looked up backwards. Nobody
29 * tested any icmp error code obviously.
30 * Alan Cox : tcp_err() now handled properly. It
31 * wakes people on errors. poll
32 * behaves and the icmp error race
33 * has gone by moving it into sock.c
34 * Alan Cox : tcp_send_reset() fixed to work for
35 * everything not just packets for
36 * unknown sockets.
37 * Alan Cox : tcp option processing.
38 * Alan Cox : Reset tweaked (still not 100%) [Had
39 * syn rule wrong]
40 * Herp Rosmanith : More reset fixes
41 * Alan Cox : No longer acks invalid rst frames.
42 * Acking any kind of RST is right out.
43 * Alan Cox : Sets an ignore me flag on an rst
44 * receive otherwise odd bits of prattle
45 * escape still
46 * Alan Cox : Fixed another acking RST frame bug.
47 * Should stop LAN workplace lockups.
48 * Alan Cox : Some tidyups using the new skb list
49 * facilities
50 * Alan Cox : sk->keepopen now seems to work
51 * Alan Cox : Pulls options out correctly on accepts
52 * Alan Cox : Fixed assorted sk->rqueue->next errors
53 * Alan Cox : PSH doesn't end a TCP read. Switched a
54 * bit to skb ops.
55 * Alan Cox : Tidied tcp_data to avoid a potential
56 * nasty.
57 * Alan Cox : Added some better commenting, as the
58 * tcp is hard to follow
59 * Alan Cox : Removed incorrect check for 20 * psh
60 * Michael O'Reilly : ack < copied bug fix.
61 * Johannes Stille : Misc tcp fixes (not all in yet).
62 * Alan Cox : FIN with no memory -> CRASH
63 * Alan Cox : Added socket option proto entries.
64 * Also added awareness of them to accept.
65 * Alan Cox : Added TCP options (SOL_TCP)
66 * Alan Cox : Switched wakeup calls to callbacks,
67 * so the kernel can layer network
68 * sockets.
69 * Alan Cox : Use ip_tos/ip_ttl settings.
70 * Alan Cox : Handle FIN (more) properly (we hope).
71 * Alan Cox : RST frames sent on unsynchronised
72 * state ack error.
73 * Alan Cox : Put in missing check for SYN bit.
74 * Alan Cox : Added tcp_select_window() aka NET2E
75 * window non shrink trick.
76 * Alan Cox : Added a couple of small NET2E timer
77 * fixes
78 * Charles Hedrick : TCP fixes
79 * Toomas Tamm : TCP window fixes
80 * Alan Cox : Small URG fix to rlogin ^C ack fight
81 * Charles Hedrick : Rewrote most of it to actually work
82 * Linus : Rewrote tcp_read() and URG handling
83 * completely
84 * Gerhard Koerting: Fixed some missing timer handling
85 * Matthew Dillon : Reworked TCP machine states as per RFC
86 * Gerhard Koerting: PC/TCP workarounds
87 * Adam Caldwell : Assorted timer/timing errors
88 * Matthew Dillon : Fixed another RST bug
89 * Alan Cox : Move to kernel side addressing changes.
90 * Alan Cox : Beginning work on TCP fastpathing
91 * (not yet usable)
92 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
93 * Alan Cox : TCP fast path debugging
94 * Alan Cox : Window clamping
95 * Michael Riepe : Bug in tcp_check()
96 * Matt Dillon : More TCP improvements and RST bug fixes
97 * Matt Dillon : Yet more small nasties remove from the
98 * TCP code (Be very nice to this man if
99 * tcp finally works 100%) 8)
100 * Alan Cox : BSD accept semantics.
101 * Alan Cox : Reset on closedown bug.
102 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
103 * Michael Pall : Handle poll() after URG properly in
104 * all cases.
105 * Michael Pall : Undo the last fix in tcp_read_urg()
106 * (multi URG PUSH broke rlogin).
107 * Michael Pall : Fix the multi URG PUSH problem in
108 * tcp_readable(), poll() after URG
109 * works now.
110 * Michael Pall : recv(...,MSG_OOB) never blocks in the
111 * BSD api.
112 * Alan Cox : Changed the semantics of sk->socket to
113 * fix a race and a signal problem with
114 * accept() and async I/O.
115 * Alan Cox : Relaxed the rules on tcp_sendto().
116 * Yury Shevchuk : Really fixed accept() blocking problem.
117 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
118 * clients/servers which listen in on
119 * fixed ports.
120 * Alan Cox : Cleaned the above up and shrank it to
121 * a sensible code size.
122 * Alan Cox : Self connect lockup fix.
123 * Alan Cox : No connect to multicast.
124 * Ross Biro : Close unaccepted children on master
125 * socket close.
126 * Alan Cox : Reset tracing code.
127 * Alan Cox : Spurious resets on shutdown.
128 * Alan Cox : Giant 15 minute/60 second timer error
129 * Alan Cox : Small whoops in polling before an
130 * accept.
131 * Alan Cox : Kept the state trace facility since
132 * it's handy for debugging.
133 * Alan Cox : More reset handler fixes.
134 * Alan Cox : Started rewriting the code based on
135 * the RFC's for other useful protocol
136 * references see: Comer, KA9Q NOS, and
137 * for a reference on the difference
138 * between specifications and how BSD
139 * works see the 4.4lite source.
140 * A.N.Kuznetsov : Don't time wait on completion of tidy
141 * close.
142 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
143 * Linus Torvalds : Fixed BSD port reuse to work first syn
144 * Alan Cox : Reimplemented timers as per the RFC
145 * and using multiple timers for sanity.
146 * Alan Cox : Small bug fixes, and a lot of new
147 * comments.
148 * Alan Cox : Fixed dual reader crash by locking
149 * the buffers (much like datagram.c)
150 * Alan Cox : Fixed stuck sockets in probe. A probe
151 * now gets fed up of retrying without
152 * (even a no space) answer.
153 * Alan Cox : Extracted closing code better
154 * Alan Cox : Fixed the closing state machine to
155 * resemble the RFC.
156 * Alan Cox : More 'per spec' fixes.
157 * Jorge Cwik : Even faster checksumming.
158 * Alan Cox : tcp_data() doesn't ack illegal PSH
159 * only frames. At least one pc tcp stack
160 * generates them.
161 * Alan Cox : Cache last socket.
162 * Alan Cox : Per route irtt.
163 * Matt Day : poll()->select() match BSD precisely on error
164 * Alan Cox : New buffers
165 * Marc Tamsky : Various sk->prot->retransmits and
166 * sk->retransmits misupdating fixed.
167 * Fixed tcp_write_timeout: stuck close,
168 * and TCP syn retries gets used now.
169 * Mark Yarvis : In tcp_read_wakeup(), don't send an
170 * ack if state is TCP_CLOSED.
171 * Alan Cox : Look up device on a retransmit - routes may
172 * change. Doesn't yet cope with MSS shrink right
173 * but it's a start!
174 * Marc Tamsky : Closing in closing fixes.
175 * Mike Shaver : RFC1122 verifications.
176 * Alan Cox : rcv_saddr errors.
177 * Alan Cox : Block double connect().
178 * Alan Cox : Small hooks for enSKIP.
179 * Alexey Kuznetsov: Path MTU discovery.
180 * Alan Cox : Support soft errors.
181 * Alan Cox : Fix MTU discovery pathological case
182 * when the remote claims no mtu!
183 * Marc Tamsky : TCP_CLOSE fix.
184 * Colin (G3TNE) : Send a reset on syn ack replies in
185 * window but wrong (fixes NT lpd problems)
186 * Pedro Roque : Better TCP window handling, delayed ack.
187 * Joerg Reuter : No modification of locked buffers in
188 * tcp_do_retransmit()
189 * Eric Schenk : Changed receiver side silly window
190 * avoidance algorithm to BSD style
191 * algorithm. This doubles throughput
192 * against machines running Solaris,
193 * and seems to result in general
194 * improvement.
195 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
196 * Willy Konynenberg : Transparent proxying support.
197 * Mike McLagan : Routing by source
198 * Keith Owens : Do proper merging with partial SKB's in
199 * tcp_do_sendmsg to avoid burstiness.
200 * Eric Schenk : Fix fast close down bug with
201 * shutdown() followed by close().
202 * Andi Kleen : Make poll agree with SIGIO
203 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
204 * lingertime == 0 (RFC 793 ABORT Call)
205 * Hirokazu Takahashi : Use copy_from_user() instead of
206 * csum_and_copy_from_user() if possible.
207 *
208 * This program is free software; you can redistribute it and/or
209 * modify it under the terms of the GNU General Public License
210 * as published by the Free Software Foundation; either version
211 * 2 of the License, or(at your option) any later version.
212 *
213 * Description of States:
214 *
215 * TCP_SYN_SENT sent a connection request, waiting for ack
216 *
217 * TCP_SYN_RECV received a connection request, sent ack,
218 * waiting for final ack in three-way handshake.
219 *
220 * TCP_ESTABLISHED connection established
221 *
222 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
223 * transmission of remaining buffered data
224 *
225 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
226 * to shutdown
227 *
228 * TCP_CLOSING both sides have shutdown but we still have
229 * data we have to finish sending
230 *
231 * TCP_TIME_WAIT timeout to catch resent junk before entering
232 * closed, can only be entered from FIN_WAIT2
233 * or CLOSING. Required because the other end
234 * may not have gotten our last ACK causing it
235 * to retransmit the data packet (which we ignore)
236 *
237 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
238 * us to finish writing our data and to shutdown
239 * (we have to close() to move on to LAST_ACK)
240 *
241 * TCP_LAST_ACK out side has shutdown after remote has
242 * shutdown. There may still be data in our
243 * buffer that we have to finish sending
244 *
245 * TCP_CLOSE socket is finished
246 */
247
248 #define pr_fmt(fmt) "TCP: " fmt
249
250 #include <linux/kernel.h>
251 #include <linux/module.h>
252 #include <linux/types.h>
253 #include <linux/fcntl.h>
254 #include <linux/poll.h>
255 #include <linux/init.h>
256 #include <linux/fs.h>
257 #include <linux/skbuff.h>
258 #include <linux/scatterlist.h>
259 #include <linux/splice.h>
260 #include <linux/net.h>
261 #include <linux/socket.h>
262 #include <linux/random.h>
263 #include <linux/bootmem.h>
264 #include <linux/highmem.h>
265 #include <linux/swap.h>
266 #include <linux/cache.h>
267 #include <linux/err.h>
268 #include <linux/crypto.h>
269 #include <linux/time.h>
270 #include <linux/slab.h>
271
272 #include <net/icmp.h>
273 #include <net/inet_common.h>
274 #include <net/tcp.h>
275 #include <net/xfrm.h>
276 #include <net/ip.h>
277 #include <net/sock.h>
278
279 #include <asm/uaccess.h>
280 #include <asm/ioctls.h>
281 #include <net/busy_poll.h>
282
283 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
284
285 int sysctl_tcp_min_tso_segs __read_mostly = 2;
286
287 int sysctl_tcp_autocorking __read_mostly = 1;
288
289 struct percpu_counter tcp_orphan_count;
290 EXPORT_SYMBOL_GPL(tcp_orphan_count);
291
292 long sysctl_tcp_mem[3] __read_mostly;
293 int sysctl_tcp_wmem[3] __read_mostly;
294 int sysctl_tcp_rmem[3] __read_mostly;
295
296 EXPORT_SYMBOL(sysctl_tcp_mem);
297 EXPORT_SYMBOL(sysctl_tcp_rmem);
298 EXPORT_SYMBOL(sysctl_tcp_wmem);
299
300 atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
301 EXPORT_SYMBOL(tcp_memory_allocated);
302
303 /*
304 * Current number of TCP sockets.
305 */
306 struct percpu_counter tcp_sockets_allocated;
307 EXPORT_SYMBOL(tcp_sockets_allocated);
308
309 /*
310 * TCP splice context
311 */
312 struct tcp_splice_state {
313 struct pipe_inode_info *pipe;
314 size_t len;
315 unsigned int flags;
316 };
317
318 /*
319 * Pressure flag: try to collapse.
320 * Technical note: it is used by multiple contexts non atomically.
321 * All the __sk_mem_schedule() is of this nature: accounting
322 * is strict, actions are advisory and have some latency.
323 */
324 int tcp_memory_pressure __read_mostly;
325 EXPORT_SYMBOL(tcp_memory_pressure);
326
327 void tcp_enter_memory_pressure(struct sock *sk)
328 {
329 if (!tcp_memory_pressure) {
330 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
331 tcp_memory_pressure = 1;
332 }
333 }
334 EXPORT_SYMBOL(tcp_enter_memory_pressure);
335
336 /* Convert seconds to retransmits based on initial and max timeout */
337 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
338 {
339 u8 res = 0;
340
341 if (seconds > 0) {
342 int period = timeout;
343
344 res = 1;
345 while (seconds > period && res < 255) {
346 res++;
347 timeout <<= 1;
348 if (timeout > rto_max)
349 timeout = rto_max;
350 period += timeout;
351 }
352 }
353 return res;
354 }
355
356 /* Convert retransmits to seconds based on initial and max timeout */
357 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
358 {
359 int period = 0;
360
361 if (retrans > 0) {
362 period = timeout;
363 while (--retrans) {
364 timeout <<= 1;
365 if (timeout > rto_max)
366 timeout = rto_max;
367 period += timeout;
368 }
369 }
370 return period;
371 }
372
373 /* Address-family independent initialization for a tcp_sock.
374 *
375 * NOTE: A lot of things set to zero explicitly by call to
376 * sk_alloc() so need not be done here.
377 */
378 void tcp_init_sock(struct sock *sk)
379 {
380 struct inet_connection_sock *icsk = inet_csk(sk);
381 struct tcp_sock *tp = tcp_sk(sk);
382
383 __skb_queue_head_init(&tp->out_of_order_queue);
384 tcp_init_xmit_timers(sk);
385 tcp_prequeue_init(tp);
386 INIT_LIST_HEAD(&tp->tsq_node);
387
388 icsk->icsk_rto = TCP_TIMEOUT_INIT;
389 tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
390
391 /* So many TCP implementations out there (incorrectly) count the
392 * initial SYN frame in their delayed-ACK and congestion control
393 * algorithms that we must have the following bandaid to talk
394 * efficiently to them. -DaveM
395 */
396 tp->snd_cwnd = TCP_INIT_CWND;
397
398 /* See draft-stevens-tcpca-spec-01 for discussion of the
399 * initialization of these values.
400 */
401 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
402 tp->snd_cwnd_clamp = ~0;
403 tp->mss_cache = TCP_MSS_DEFAULT;
404
405 tp->reordering = sysctl_tcp_reordering;
406 tcp_enable_early_retrans(tp);
407 tcp_assign_congestion_control(sk);
408
409 tp->tsoffset = 0;
410
411 sk->sk_state = TCP_CLOSE;
412
413 sk->sk_write_space = sk_stream_write_space;
414 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
415
416 icsk->icsk_sync_mss = tcp_sync_mss;
417
418 sk->sk_sndbuf = sysctl_tcp_wmem[1];
419 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
420
421 local_bh_disable();
422 sock_update_memcg(sk);
423 sk_sockets_allocated_inc(sk);
424 local_bh_enable();
425 }
426 EXPORT_SYMBOL(tcp_init_sock);
427
428 static void tcp_tx_timestamp(struct sock *sk, struct sk_buff *skb)
429 {
430 if (sk->sk_tsflags) {
431 struct skb_shared_info *shinfo = skb_shinfo(skb);
432
433 sock_tx_timestamp(sk, &shinfo->tx_flags);
434 if (shinfo->tx_flags & SKBTX_ANY_TSTAMP)
435 shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
436 }
437 }
438
439 /*
440 * Wait for a TCP event.
441 *
442 * Note that we don't need to lock the socket, as the upper poll layers
443 * take care of normal races (between the test and the event) and we don't
444 * go look at any of the socket buffers directly.
445 */
446 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
447 {
448 unsigned int mask;
449 struct sock *sk = sock->sk;
450 const struct tcp_sock *tp = tcp_sk(sk);
451
452 sock_rps_record_flow(sk);
453
454 sock_poll_wait(file, sk_sleep(sk), wait);
455 if (sk->sk_state == TCP_LISTEN)
456 return inet_csk_listen_poll(sk);
457
458 /* Socket is not locked. We are protected from async events
459 * by poll logic and correct handling of state changes
460 * made by other threads is impossible in any case.
461 */
462
463 mask = 0;
464
465 /*
466 * POLLHUP is certainly not done right. But poll() doesn't
467 * have a notion of HUP in just one direction, and for a
468 * socket the read side is more interesting.
469 *
470 * Some poll() documentation says that POLLHUP is incompatible
471 * with the POLLOUT/POLLWR flags, so somebody should check this
472 * all. But careful, it tends to be safer to return too many
473 * bits than too few, and you can easily break real applications
474 * if you don't tell them that something has hung up!
475 *
476 * Check-me.
477 *
478 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
479 * our fs/select.c). It means that after we received EOF,
480 * poll always returns immediately, making impossible poll() on write()
481 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
482 * if and only if shutdown has been made in both directions.
483 * Actually, it is interesting to look how Solaris and DUX
484 * solve this dilemma. I would prefer, if POLLHUP were maskable,
485 * then we could set it on SND_SHUTDOWN. BTW examples given
486 * in Stevens' books assume exactly this behaviour, it explains
487 * why POLLHUP is incompatible with POLLOUT. --ANK
488 *
489 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
490 * blocking on fresh not-connected or disconnected socket. --ANK
491 */
492 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
493 mask |= POLLHUP;
494 if (sk->sk_shutdown & RCV_SHUTDOWN)
495 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
496
497 /* Connected or passive Fast Open socket? */
498 if (sk->sk_state != TCP_SYN_SENT &&
499 (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk != NULL)) {
500 int target = sock_rcvlowat(sk, 0, INT_MAX);
501
502 if (tp->urg_seq == tp->copied_seq &&
503 !sock_flag(sk, SOCK_URGINLINE) &&
504 tp->urg_data)
505 target++;
506
507 /* Potential race condition. If read of tp below will
508 * escape above sk->sk_state, we can be illegally awaken
509 * in SYN_* states. */
510 if (tp->rcv_nxt - tp->copied_seq >= target)
511 mask |= POLLIN | POLLRDNORM;
512
513 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
514 if (sk_stream_is_writeable(sk)) {
515 mask |= POLLOUT | POLLWRNORM;
516 } else { /* send SIGIO later */
517 set_bit(SOCK_ASYNC_NOSPACE,
518 &sk->sk_socket->flags);
519 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
520
521 /* Race breaker. If space is freed after
522 * wspace test but before the flags are set,
523 * IO signal will be lost.
524 */
525 if (sk_stream_is_writeable(sk))
526 mask |= POLLOUT | POLLWRNORM;
527 }
528 } else
529 mask |= POLLOUT | POLLWRNORM;
530
531 if (tp->urg_data & TCP_URG_VALID)
532 mask |= POLLPRI;
533 }
534 /* This barrier is coupled with smp_wmb() in tcp_reset() */
535 smp_rmb();
536 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
537 mask |= POLLERR;
538
539 return mask;
540 }
541 EXPORT_SYMBOL(tcp_poll);
542
543 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
544 {
545 struct tcp_sock *tp = tcp_sk(sk);
546 int answ;
547 bool slow;
548
549 switch (cmd) {
550 case SIOCINQ:
551 if (sk->sk_state == TCP_LISTEN)
552 return -EINVAL;
553
554 slow = lock_sock_fast(sk);
555 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
556 answ = 0;
557 else if (sock_flag(sk, SOCK_URGINLINE) ||
558 !tp->urg_data ||
559 before(tp->urg_seq, tp->copied_seq) ||
560 !before(tp->urg_seq, tp->rcv_nxt)) {
561
562 answ = tp->rcv_nxt - tp->copied_seq;
563
564 /* Subtract 1, if FIN was received */
565 if (answ && sock_flag(sk, SOCK_DONE))
566 answ--;
567 } else
568 answ = tp->urg_seq - tp->copied_seq;
569 unlock_sock_fast(sk, slow);
570 break;
571 case SIOCATMARK:
572 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
573 break;
574 case SIOCOUTQ:
575 if (sk->sk_state == TCP_LISTEN)
576 return -EINVAL;
577
578 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
579 answ = 0;
580 else
581 answ = tp->write_seq - tp->snd_una;
582 break;
583 case SIOCOUTQNSD:
584 if (sk->sk_state == TCP_LISTEN)
585 return -EINVAL;
586
587 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
588 answ = 0;
589 else
590 answ = tp->write_seq - tp->snd_nxt;
591 break;
592 default:
593 return -ENOIOCTLCMD;
594 }
595
596 return put_user(answ, (int __user *)arg);
597 }
598 EXPORT_SYMBOL(tcp_ioctl);
599
600 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
601 {
602 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
603 tp->pushed_seq = tp->write_seq;
604 }
605
606 static inline bool forced_push(const struct tcp_sock *tp)
607 {
608 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
609 }
610
611 static void skb_entail(struct sock *sk, struct sk_buff *skb)
612 {
613 struct tcp_sock *tp = tcp_sk(sk);
614 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
615
616 skb->csum = 0;
617 tcb->seq = tcb->end_seq = tp->write_seq;
618 tcb->tcp_flags = TCPHDR_ACK;
619 tcb->sacked = 0;
620 __skb_header_release(skb);
621 tcp_add_write_queue_tail(sk, skb);
622 sk->sk_wmem_queued += skb->truesize;
623 sk_mem_charge(sk, skb->truesize);
624 if (tp->nonagle & TCP_NAGLE_PUSH)
625 tp->nonagle &= ~TCP_NAGLE_PUSH;
626 }
627
628 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
629 {
630 if (flags & MSG_OOB)
631 tp->snd_up = tp->write_seq;
632 }
633
634 /* If a not yet filled skb is pushed, do not send it if
635 * we have data packets in Qdisc or NIC queues :
636 * Because TX completion will happen shortly, it gives a chance
637 * to coalesce future sendmsg() payload into this skb, without
638 * need for a timer, and with no latency trade off.
639 * As packets containing data payload have a bigger truesize
640 * than pure acks (dataless) packets, the last checks prevent
641 * autocorking if we only have an ACK in Qdisc/NIC queues,
642 * or if TX completion was delayed after we processed ACK packet.
643 */
644 static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
645 int size_goal)
646 {
647 return skb->len < size_goal &&
648 sysctl_tcp_autocorking &&
649 skb != tcp_write_queue_head(sk) &&
650 atomic_read(&sk->sk_wmem_alloc) > skb->truesize;
651 }
652
653 static void tcp_push(struct sock *sk, int flags, int mss_now,
654 int nonagle, int size_goal)
655 {
656 struct tcp_sock *tp = tcp_sk(sk);
657 struct sk_buff *skb;
658
659 if (!tcp_send_head(sk))
660 return;
661
662 skb = tcp_write_queue_tail(sk);
663 if (!(flags & MSG_MORE) || forced_push(tp))
664 tcp_mark_push(tp, skb);
665
666 tcp_mark_urg(tp, flags);
667
668 if (tcp_should_autocork(sk, skb, size_goal)) {
669
670 /* avoid atomic op if TSQ_THROTTLED bit is already set */
671 if (!test_bit(TSQ_THROTTLED, &tp->tsq_flags)) {
672 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
673 set_bit(TSQ_THROTTLED, &tp->tsq_flags);
674 }
675 /* It is possible TX completion already happened
676 * before we set TSQ_THROTTLED.
677 */
678 if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize)
679 return;
680 }
681
682 if (flags & MSG_MORE)
683 nonagle = TCP_NAGLE_CORK;
684
685 __tcp_push_pending_frames(sk, mss_now, nonagle);
686 }
687
688 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
689 unsigned int offset, size_t len)
690 {
691 struct tcp_splice_state *tss = rd_desc->arg.data;
692 int ret;
693
694 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
695 tss->flags);
696 if (ret > 0)
697 rd_desc->count -= ret;
698 return ret;
699 }
700
701 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
702 {
703 /* Store TCP splice context information in read_descriptor_t. */
704 read_descriptor_t rd_desc = {
705 .arg.data = tss,
706 .count = tss->len,
707 };
708
709 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
710 }
711
712 /**
713 * tcp_splice_read - splice data from TCP socket to a pipe
714 * @sock: socket to splice from
715 * @ppos: position (not valid)
716 * @pipe: pipe to splice to
717 * @len: number of bytes to splice
718 * @flags: splice modifier flags
719 *
720 * Description:
721 * Will read pages from given socket and fill them into a pipe.
722 *
723 **/
724 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
725 struct pipe_inode_info *pipe, size_t len,
726 unsigned int flags)
727 {
728 struct sock *sk = sock->sk;
729 struct tcp_splice_state tss = {
730 .pipe = pipe,
731 .len = len,
732 .flags = flags,
733 };
734 long timeo;
735 ssize_t spliced;
736 int ret;
737
738 sock_rps_record_flow(sk);
739 /*
740 * We can't seek on a socket input
741 */
742 if (unlikely(*ppos))
743 return -ESPIPE;
744
745 ret = spliced = 0;
746
747 lock_sock(sk);
748
749 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
750 while (tss.len) {
751 ret = __tcp_splice_read(sk, &tss);
752 if (ret < 0)
753 break;
754 else if (!ret) {
755 if (spliced)
756 break;
757 if (sock_flag(sk, SOCK_DONE))
758 break;
759 if (sk->sk_err) {
760 ret = sock_error(sk);
761 break;
762 }
763 if (sk->sk_shutdown & RCV_SHUTDOWN)
764 break;
765 if (sk->sk_state == TCP_CLOSE) {
766 /*
767 * This occurs when user tries to read
768 * from never connected socket.
769 */
770 if (!sock_flag(sk, SOCK_DONE))
771 ret = -ENOTCONN;
772 break;
773 }
774 if (!timeo) {
775 ret = -EAGAIN;
776 break;
777 }
778 sk_wait_data(sk, &timeo);
779 if (signal_pending(current)) {
780 ret = sock_intr_errno(timeo);
781 break;
782 }
783 continue;
784 }
785 tss.len -= ret;
786 spliced += ret;
787
788 if (!timeo)
789 break;
790 release_sock(sk);
791 lock_sock(sk);
792
793 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
794 (sk->sk_shutdown & RCV_SHUTDOWN) ||
795 signal_pending(current))
796 break;
797 }
798
799 release_sock(sk);
800
801 if (spliced)
802 return spliced;
803
804 return ret;
805 }
806 EXPORT_SYMBOL(tcp_splice_read);
807
808 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
809 {
810 struct sk_buff *skb;
811
812 /* The TCP header must be at least 32-bit aligned. */
813 size = ALIGN(size, 4);
814
815 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
816 if (skb) {
817 if (sk_wmem_schedule(sk, skb->truesize)) {
818 skb_reserve(skb, sk->sk_prot->max_header);
819 /*
820 * Make sure that we have exactly size bytes
821 * available to the caller, no more, no less.
822 */
823 skb->reserved_tailroom = skb->end - skb->tail - size;
824 return skb;
825 }
826 __kfree_skb(skb);
827 } else {
828 sk->sk_prot->enter_memory_pressure(sk);
829 sk_stream_moderate_sndbuf(sk);
830 }
831 return NULL;
832 }
833
834 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
835 int large_allowed)
836 {
837 struct tcp_sock *tp = tcp_sk(sk);
838 u32 new_size_goal, size_goal, hlen;
839
840 if (!large_allowed || !sk_can_gso(sk))
841 return mss_now;
842
843 /* Maybe we should/could use sk->sk_prot->max_header here ? */
844 hlen = inet_csk(sk)->icsk_af_ops->net_header_len +
845 inet_csk(sk)->icsk_ext_hdr_len +
846 tp->tcp_header_len;
847
848 new_size_goal = sk->sk_gso_max_size - 1 - hlen;
849 new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);
850
851 /* We try hard to avoid divides here */
852 size_goal = tp->gso_segs * mss_now;
853 if (unlikely(new_size_goal < size_goal ||
854 new_size_goal >= size_goal + mss_now)) {
855 tp->gso_segs = min_t(u16, new_size_goal / mss_now,
856 sk->sk_gso_max_segs);
857 size_goal = tp->gso_segs * mss_now;
858 }
859
860 return max(size_goal, mss_now);
861 }
862
863 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
864 {
865 int mss_now;
866
867 mss_now = tcp_current_mss(sk);
868 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
869
870 return mss_now;
871 }
872
873 static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
874 size_t size, int flags)
875 {
876 struct tcp_sock *tp = tcp_sk(sk);
877 int mss_now, size_goal;
878 int err;
879 ssize_t copied;
880 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
881
882 /* Wait for a connection to finish. One exception is TCP Fast Open
883 * (passive side) where data is allowed to be sent before a connection
884 * is fully established.
885 */
886 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
887 !tcp_passive_fastopen(sk)) {
888 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
889 goto out_err;
890 }
891
892 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
893
894 mss_now = tcp_send_mss(sk, &size_goal, flags);
895 copied = 0;
896
897 err = -EPIPE;
898 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
899 goto out_err;
900
901 while (size > 0) {
902 struct sk_buff *skb = tcp_write_queue_tail(sk);
903 int copy, i;
904 bool can_coalesce;
905
906 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
907 new_segment:
908 if (!sk_stream_memory_free(sk))
909 goto wait_for_sndbuf;
910
911 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
912 if (!skb)
913 goto wait_for_memory;
914
915 skb_entail(sk, skb);
916 copy = size_goal;
917 }
918
919 if (copy > size)
920 copy = size;
921
922 i = skb_shinfo(skb)->nr_frags;
923 can_coalesce = skb_can_coalesce(skb, i, page, offset);
924 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
925 tcp_mark_push(tp, skb);
926 goto new_segment;
927 }
928 if (!sk_wmem_schedule(sk, copy))
929 goto wait_for_memory;
930
931 if (can_coalesce) {
932 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
933 } else {
934 get_page(page);
935 skb_fill_page_desc(skb, i, page, offset, copy);
936 }
937 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
938
939 skb->len += copy;
940 skb->data_len += copy;
941 skb->truesize += copy;
942 sk->sk_wmem_queued += copy;
943 sk_mem_charge(sk, copy);
944 skb->ip_summed = CHECKSUM_PARTIAL;
945 tp->write_seq += copy;
946 TCP_SKB_CB(skb)->end_seq += copy;
947 tcp_skb_pcount_set(skb, 0);
948
949 if (!copied)
950 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
951
952 copied += copy;
953 offset += copy;
954 if (!(size -= copy)) {
955 tcp_tx_timestamp(sk, skb);
956 goto out;
957 }
958
959 if (skb->len < size_goal || (flags & MSG_OOB))
960 continue;
961
962 if (forced_push(tp)) {
963 tcp_mark_push(tp, skb);
964 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
965 } else if (skb == tcp_send_head(sk))
966 tcp_push_one(sk, mss_now);
967 continue;
968
969 wait_for_sndbuf:
970 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
971 wait_for_memory:
972 tcp_push(sk, flags & ~MSG_MORE, mss_now,
973 TCP_NAGLE_PUSH, size_goal);
974
975 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
976 goto do_error;
977
978 mss_now = tcp_send_mss(sk, &size_goal, flags);
979 }
980
981 out:
982 if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
983 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
984 return copied;
985
986 do_error:
987 if (copied)
988 goto out;
989 out_err:
990 return sk_stream_error(sk, flags, err);
991 }
992
993 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
994 size_t size, int flags)
995 {
996 ssize_t res;
997
998 if (!(sk->sk_route_caps & NETIF_F_SG) ||
999 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
1000 return sock_no_sendpage(sk->sk_socket, page, offset, size,
1001 flags);
1002
1003 lock_sock(sk);
1004 res = do_tcp_sendpages(sk, page, offset, size, flags);
1005 release_sock(sk);
1006 return res;
1007 }
1008 EXPORT_SYMBOL(tcp_sendpage);
1009
1010 static inline int select_size(const struct sock *sk, bool sg)
1011 {
1012 const struct tcp_sock *tp = tcp_sk(sk);
1013 int tmp = tp->mss_cache;
1014
1015 if (sg) {
1016 if (sk_can_gso(sk)) {
1017 /* Small frames wont use a full page:
1018 * Payload will immediately follow tcp header.
1019 */
1020 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
1021 } else {
1022 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
1023
1024 if (tmp >= pgbreak &&
1025 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
1026 tmp = pgbreak;
1027 }
1028 }
1029
1030 return tmp;
1031 }
1032
1033 void tcp_free_fastopen_req(struct tcp_sock *tp)
1034 {
1035 if (tp->fastopen_req != NULL) {
1036 kfree(tp->fastopen_req);
1037 tp->fastopen_req = NULL;
1038 }
1039 }
1040
1041 static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1042 int *copied, size_t size)
1043 {
1044 struct tcp_sock *tp = tcp_sk(sk);
1045 int err, flags;
1046
1047 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
1048 return -EOPNOTSUPP;
1049 if (tp->fastopen_req != NULL)
1050 return -EALREADY; /* Another Fast Open is in progress */
1051
1052 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1053 sk->sk_allocation);
1054 if (unlikely(tp->fastopen_req == NULL))
1055 return -ENOBUFS;
1056 tp->fastopen_req->data = msg;
1057 tp->fastopen_req->size = size;
1058
1059 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1060 err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1061 msg->msg_namelen, flags);
1062 *copied = tp->fastopen_req->copied;
1063 tcp_free_fastopen_req(tp);
1064 return err;
1065 }
1066
1067 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1068 size_t size)
1069 {
1070 const struct iovec *iov;
1071 struct tcp_sock *tp = tcp_sk(sk);
1072 struct sk_buff *skb;
1073 int iovlen, flags, err, copied = 0;
1074 int mss_now = 0, size_goal, copied_syn = 0, offset = 0;
1075 bool sg;
1076 long timeo;
1077
1078 lock_sock(sk);
1079
1080 flags = msg->msg_flags;
1081 if (flags & MSG_FASTOPEN) {
1082 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1083 if (err == -EINPROGRESS && copied_syn > 0)
1084 goto out;
1085 else if (err)
1086 goto out_err;
1087 offset = copied_syn;
1088 }
1089
1090 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1091
1092 /* Wait for a connection to finish. One exception is TCP Fast Open
1093 * (passive side) where data is allowed to be sent before a connection
1094 * is fully established.
1095 */
1096 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1097 !tcp_passive_fastopen(sk)) {
1098 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1099 goto do_error;
1100 }
1101
1102 if (unlikely(tp->repair)) {
1103 if (tp->repair_queue == TCP_RECV_QUEUE) {
1104 copied = tcp_send_rcvq(sk, msg, size);
1105 goto out_nopush;
1106 }
1107
1108 err = -EINVAL;
1109 if (tp->repair_queue == TCP_NO_QUEUE)
1110 goto out_err;
1111
1112 /* 'common' sending to sendq */
1113 }
1114
1115 /* This should be in poll */
1116 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1117
1118 mss_now = tcp_send_mss(sk, &size_goal, flags);
1119
1120 /* Ok commence sending. */
1121 iovlen = msg->msg_iter.nr_segs;
1122 iov = msg->msg_iter.iov;
1123 copied = 0;
1124
1125 err = -EPIPE;
1126 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1127 goto out_err;
1128
1129 sg = !!(sk->sk_route_caps & NETIF_F_SG);
1130
1131 while (--iovlen >= 0) {
1132 size_t seglen = iov->iov_len;
1133 unsigned char __user *from = iov->iov_base;
1134
1135 iov++;
1136 if (unlikely(offset > 0)) { /* Skip bytes copied in SYN */
1137 if (offset >= seglen) {
1138 offset -= seglen;
1139 continue;
1140 }
1141 seglen -= offset;
1142 from += offset;
1143 offset = 0;
1144 }
1145
1146 while (seglen > 0) {
1147 int copy = 0;
1148 int max = size_goal;
1149
1150 skb = tcp_write_queue_tail(sk);
1151 if (tcp_send_head(sk)) {
1152 if (skb->ip_summed == CHECKSUM_NONE)
1153 max = mss_now;
1154 copy = max - skb->len;
1155 }
1156
1157 if (copy <= 0) {
1158 new_segment:
1159 /* Allocate new segment. If the interface is SG,
1160 * allocate skb fitting to single page.
1161 */
1162 if (!sk_stream_memory_free(sk))
1163 goto wait_for_sndbuf;
1164
1165 skb = sk_stream_alloc_skb(sk,
1166 select_size(sk, sg),
1167 sk->sk_allocation);
1168 if (!skb)
1169 goto wait_for_memory;
1170
1171 /*
1172 * Check whether we can use HW checksum.
1173 */
1174 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1175 skb->ip_summed = CHECKSUM_PARTIAL;
1176
1177 skb_entail(sk, skb);
1178 copy = size_goal;
1179 max = size_goal;
1180
1181 /* All packets are restored as if they have
1182 * already been sent. skb_mstamp isn't set to
1183 * avoid wrong rtt estimation.
1184 */
1185 if (tp->repair)
1186 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
1187 }
1188
1189 /* Try to append data to the end of skb. */
1190 if (copy > seglen)
1191 copy = seglen;
1192
1193 /* Where to copy to? */
1194 if (skb_availroom(skb) > 0) {
1195 /* We have some space in skb head. Superb! */
1196 copy = min_t(int, copy, skb_availroom(skb));
1197 err = skb_add_data_nocache(sk, skb, from, copy);
1198 if (err)
1199 goto do_fault;
1200 } else {
1201 bool merge = true;
1202 int i = skb_shinfo(skb)->nr_frags;
1203 struct page_frag *pfrag = sk_page_frag(sk);
1204
1205 if (!sk_page_frag_refill(sk, pfrag))
1206 goto wait_for_memory;
1207
1208 if (!skb_can_coalesce(skb, i, pfrag->page,
1209 pfrag->offset)) {
1210 if (i == MAX_SKB_FRAGS || !sg) {
1211 tcp_mark_push(tp, skb);
1212 goto new_segment;
1213 }
1214 merge = false;
1215 }
1216
1217 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1218
1219 if (!sk_wmem_schedule(sk, copy))
1220 goto wait_for_memory;
1221
1222 err = skb_copy_to_page_nocache(sk, from, skb,
1223 pfrag->page,
1224 pfrag->offset,
1225 copy);
1226 if (err)
1227 goto do_error;
1228
1229 /* Update the skb. */
1230 if (merge) {
1231 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1232 } else {
1233 skb_fill_page_desc(skb, i, pfrag->page,
1234 pfrag->offset, copy);
1235 get_page(pfrag->page);
1236 }
1237 pfrag->offset += copy;
1238 }
1239
1240 if (!copied)
1241 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1242
1243 tp->write_seq += copy;
1244 TCP_SKB_CB(skb)->end_seq += copy;
1245 tcp_skb_pcount_set(skb, 0);
1246
1247 from += copy;
1248 copied += copy;
1249 if ((seglen -= copy) == 0 && iovlen == 0) {
1250 tcp_tx_timestamp(sk, skb);
1251 goto out;
1252 }
1253
1254 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1255 continue;
1256
1257 if (forced_push(tp)) {
1258 tcp_mark_push(tp, skb);
1259 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1260 } else if (skb == tcp_send_head(sk))
1261 tcp_push_one(sk, mss_now);
1262 continue;
1263
1264 wait_for_sndbuf:
1265 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1266 wait_for_memory:
1267 if (copied)
1268 tcp_push(sk, flags & ~MSG_MORE, mss_now,
1269 TCP_NAGLE_PUSH, size_goal);
1270
1271 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1272 goto do_error;
1273
1274 mss_now = tcp_send_mss(sk, &size_goal, flags);
1275 }
1276 }
1277
1278 out:
1279 if (copied)
1280 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1281 out_nopush:
1282 release_sock(sk);
1283 return copied + copied_syn;
1284
1285 do_fault:
1286 if (!skb->len) {
1287 tcp_unlink_write_queue(skb, sk);
1288 /* It is the one place in all of TCP, except connection
1289 * reset, where we can be unlinking the send_head.
1290 */
1291 tcp_check_send_head(sk, skb);
1292 sk_wmem_free_skb(sk, skb);
1293 }
1294
1295 do_error:
1296 if (copied + copied_syn)
1297 goto out;
1298 out_err:
1299 err = sk_stream_error(sk, flags, err);
1300 release_sock(sk);
1301 return err;
1302 }
1303 EXPORT_SYMBOL(tcp_sendmsg);
1304
1305 /*
1306 * Handle reading urgent data. BSD has very simple semantics for
1307 * this, no blocking and very strange errors 8)
1308 */
1309
1310 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1311 {
1312 struct tcp_sock *tp = tcp_sk(sk);
1313
1314 /* No URG data to read. */
1315 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1316 tp->urg_data == TCP_URG_READ)
1317 return -EINVAL; /* Yes this is right ! */
1318
1319 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1320 return -ENOTCONN;
1321
1322 if (tp->urg_data & TCP_URG_VALID) {
1323 int err = 0;
1324 char c = tp->urg_data;
1325
1326 if (!(flags & MSG_PEEK))
1327 tp->urg_data = TCP_URG_READ;
1328
1329 /* Read urgent data. */
1330 msg->msg_flags |= MSG_OOB;
1331
1332 if (len > 0) {
1333 if (!(flags & MSG_TRUNC))
1334 err = memcpy_to_msg(msg, &c, 1);
1335 len = 1;
1336 } else
1337 msg->msg_flags |= MSG_TRUNC;
1338
1339 return err ? -EFAULT : len;
1340 }
1341
1342 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1343 return 0;
1344
1345 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1346 * the available implementations agree in this case:
1347 * this call should never block, independent of the
1348 * blocking state of the socket.
1349 * Mike <pall@rz.uni-karlsruhe.de>
1350 */
1351 return -EAGAIN;
1352 }
1353
1354 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1355 {
1356 struct sk_buff *skb;
1357 int copied = 0, err = 0;
1358
1359 /* XXX -- need to support SO_PEEK_OFF */
1360
1361 skb_queue_walk(&sk->sk_write_queue, skb) {
1362 err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
1363 if (err)
1364 break;
1365
1366 copied += skb->len;
1367 }
1368
1369 return err ?: copied;
1370 }
1371
1372 /* Clean up the receive buffer for full frames taken by the user,
1373 * then send an ACK if necessary. COPIED is the number of bytes
1374 * tcp_recvmsg has given to the user so far, it speeds up the
1375 * calculation of whether or not we must ACK for the sake of
1376 * a window update.
1377 */
1378 static void tcp_cleanup_rbuf(struct sock *sk, int copied)
1379 {
1380 struct tcp_sock *tp = tcp_sk(sk);
1381 bool time_to_ack = false;
1382
1383 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1384
1385 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1386 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1387 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1388
1389 if (inet_csk_ack_scheduled(sk)) {
1390 const struct inet_connection_sock *icsk = inet_csk(sk);
1391 /* Delayed ACKs frequently hit locked sockets during bulk
1392 * receive. */
1393 if (icsk->icsk_ack.blocked ||
1394 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1395 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1396 /*
1397 * If this read emptied read buffer, we send ACK, if
1398 * connection is not bidirectional, user drained
1399 * receive buffer and there was a small segment
1400 * in queue.
1401 */
1402 (copied > 0 &&
1403 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1404 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1405 !icsk->icsk_ack.pingpong)) &&
1406 !atomic_read(&sk->sk_rmem_alloc)))
1407 time_to_ack = true;
1408 }
1409
1410 /* We send an ACK if we can now advertise a non-zero window
1411 * which has been raised "significantly".
1412 *
1413 * Even if window raised up to infinity, do not send window open ACK
1414 * in states, where we will not receive more. It is useless.
1415 */
1416 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1417 __u32 rcv_window_now = tcp_receive_window(tp);
1418
1419 /* Optimize, __tcp_select_window() is not cheap. */
1420 if (2*rcv_window_now <= tp->window_clamp) {
1421 __u32 new_window = __tcp_select_window(sk);
1422
1423 /* Send ACK now, if this read freed lots of space
1424 * in our buffer. Certainly, new_window is new window.
1425 * We can advertise it now, if it is not less than current one.
1426 * "Lots" means "at least twice" here.
1427 */
1428 if (new_window && new_window >= 2 * rcv_window_now)
1429 time_to_ack = true;
1430 }
1431 }
1432 if (time_to_ack)
1433 tcp_send_ack(sk);
1434 }
1435
1436 static void tcp_prequeue_process(struct sock *sk)
1437 {
1438 struct sk_buff *skb;
1439 struct tcp_sock *tp = tcp_sk(sk);
1440
1441 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1442
1443 /* RX process wants to run with disabled BHs, though it is not
1444 * necessary */
1445 local_bh_disable();
1446 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1447 sk_backlog_rcv(sk, skb);
1448 local_bh_enable();
1449
1450 /* Clear memory counter. */
1451 tp->ucopy.memory = 0;
1452 }
1453
1454 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1455 {
1456 struct sk_buff *skb;
1457 u32 offset;
1458
1459 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1460 offset = seq - TCP_SKB_CB(skb)->seq;
1461 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
1462 offset--;
1463 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
1464 *off = offset;
1465 return skb;
1466 }
1467 /* This looks weird, but this can happen if TCP collapsing
1468 * splitted a fat GRO packet, while we released socket lock
1469 * in skb_splice_bits()
1470 */
1471 sk_eat_skb(sk, skb);
1472 }
1473 return NULL;
1474 }
1475
1476 /*
1477 * This routine provides an alternative to tcp_recvmsg() for routines
1478 * that would like to handle copying from skbuffs directly in 'sendfile'
1479 * fashion.
1480 * Note:
1481 * - It is assumed that the socket was locked by the caller.
1482 * - The routine does not block.
1483 * - At present, there is no support for reading OOB data
1484 * or for 'peeking' the socket using this routine
1485 * (although both would be easy to implement).
1486 */
1487 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1488 sk_read_actor_t recv_actor)
1489 {
1490 struct sk_buff *skb;
1491 struct tcp_sock *tp = tcp_sk(sk);
1492 u32 seq = tp->copied_seq;
1493 u32 offset;
1494 int copied = 0;
1495
1496 if (sk->sk_state == TCP_LISTEN)
1497 return -ENOTCONN;
1498 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1499 if (offset < skb->len) {
1500 int used;
1501 size_t len;
1502
1503 len = skb->len - offset;
1504 /* Stop reading if we hit a patch of urgent data */
1505 if (tp->urg_data) {
1506 u32 urg_offset = tp->urg_seq - seq;
1507 if (urg_offset < len)
1508 len = urg_offset;
1509 if (!len)
1510 break;
1511 }
1512 used = recv_actor(desc, skb, offset, len);
1513 if (used <= 0) {
1514 if (!copied)
1515 copied = used;
1516 break;
1517 } else if (used <= len) {
1518 seq += used;
1519 copied += used;
1520 offset += used;
1521 }
1522 /* If recv_actor drops the lock (e.g. TCP splice
1523 * receive) the skb pointer might be invalid when
1524 * getting here: tcp_collapse might have deleted it
1525 * while aggregating skbs from the socket queue.
1526 */
1527 skb = tcp_recv_skb(sk, seq - 1, &offset);
1528 if (!skb)
1529 break;
1530 /* TCP coalescing might have appended data to the skb.
1531 * Try to splice more frags
1532 */
1533 if (offset + 1 != skb->len)
1534 continue;
1535 }
1536 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1537 sk_eat_skb(sk, skb);
1538 ++seq;
1539 break;
1540 }
1541 sk_eat_skb(sk, skb);
1542 if (!desc->count)
1543 break;
1544 tp->copied_seq = seq;
1545 }
1546 tp->copied_seq = seq;
1547
1548 tcp_rcv_space_adjust(sk);
1549
1550 /* Clean up data we have read: This will do ACK frames. */
1551 if (copied > 0) {
1552 tcp_recv_skb(sk, seq, &offset);
1553 tcp_cleanup_rbuf(sk, copied);
1554 }
1555 return copied;
1556 }
1557 EXPORT_SYMBOL(tcp_read_sock);
1558
1559 /*
1560 * This routine copies from a sock struct into the user buffer.
1561 *
1562 * Technical note: in 2.3 we work on _locked_ socket, so that
1563 * tricks with *seq access order and skb->users are not required.
1564 * Probably, code can be easily improved even more.
1565 */
1566
1567 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1568 size_t len, int nonblock, int flags, int *addr_len)
1569 {
1570 struct tcp_sock *tp = tcp_sk(sk);
1571 int copied = 0;
1572 u32 peek_seq;
1573 u32 *seq;
1574 unsigned long used;
1575 int err;
1576 int target; /* Read at least this many bytes */
1577 long timeo;
1578 struct task_struct *user_recv = NULL;
1579 struct sk_buff *skb;
1580 u32 urg_hole = 0;
1581
1582 if (unlikely(flags & MSG_ERRQUEUE))
1583 return inet_recv_error(sk, msg, len, addr_len);
1584
1585 if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
1586 (sk->sk_state == TCP_ESTABLISHED))
1587 sk_busy_loop(sk, nonblock);
1588
1589 lock_sock(sk);
1590
1591 err = -ENOTCONN;
1592 if (sk->sk_state == TCP_LISTEN)
1593 goto out;
1594
1595 timeo = sock_rcvtimeo(sk, nonblock);
1596
1597 /* Urgent data needs to be handled specially. */
1598 if (flags & MSG_OOB)
1599 goto recv_urg;
1600
1601 if (unlikely(tp->repair)) {
1602 err = -EPERM;
1603 if (!(flags & MSG_PEEK))
1604 goto out;
1605
1606 if (tp->repair_queue == TCP_SEND_QUEUE)
1607 goto recv_sndq;
1608
1609 err = -EINVAL;
1610 if (tp->repair_queue == TCP_NO_QUEUE)
1611 goto out;
1612
1613 /* 'common' recv queue MSG_PEEK-ing */
1614 }
1615
1616 seq = &tp->copied_seq;
1617 if (flags & MSG_PEEK) {
1618 peek_seq = tp->copied_seq;
1619 seq = &peek_seq;
1620 }
1621
1622 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1623
1624 do {
1625 u32 offset;
1626
1627 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1628 if (tp->urg_data && tp->urg_seq == *seq) {
1629 if (copied)
1630 break;
1631 if (signal_pending(current)) {
1632 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1633 break;
1634 }
1635 }
1636
1637 /* Next get a buffer. */
1638
1639 skb_queue_walk(&sk->sk_receive_queue, skb) {
1640 /* Now that we have two receive queues this
1641 * shouldn't happen.
1642 */
1643 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1644 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1645 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1646 flags))
1647 break;
1648
1649 offset = *seq - TCP_SKB_CB(skb)->seq;
1650 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
1651 offset--;
1652 if (offset < skb->len)
1653 goto found_ok_skb;
1654 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1655 goto found_fin_ok;
1656 WARN(!(flags & MSG_PEEK),
1657 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1658 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1659 }
1660
1661 /* Well, if we have backlog, try to process it now yet. */
1662
1663 if (copied >= target && !sk->sk_backlog.tail)
1664 break;
1665
1666 if (copied) {
1667 if (sk->sk_err ||
1668 sk->sk_state == TCP_CLOSE ||
1669 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1670 !timeo ||
1671 signal_pending(current))
1672 break;
1673 } else {
1674 if (sock_flag(sk, SOCK_DONE))
1675 break;
1676
1677 if (sk->sk_err) {
1678 copied = sock_error(sk);
1679 break;
1680 }
1681
1682 if (sk->sk_shutdown & RCV_SHUTDOWN)
1683 break;
1684
1685 if (sk->sk_state == TCP_CLOSE) {
1686 if (!sock_flag(sk, SOCK_DONE)) {
1687 /* This occurs when user tries to read
1688 * from never connected socket.
1689 */
1690 copied = -ENOTCONN;
1691 break;
1692 }
1693 break;
1694 }
1695
1696 if (!timeo) {
1697 copied = -EAGAIN;
1698 break;
1699 }
1700
1701 if (signal_pending(current)) {
1702 copied = sock_intr_errno(timeo);
1703 break;
1704 }
1705 }
1706
1707 tcp_cleanup_rbuf(sk, copied);
1708
1709 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1710 /* Install new reader */
1711 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1712 user_recv = current;
1713 tp->ucopy.task = user_recv;
1714 tp->ucopy.msg = msg;
1715 }
1716
1717 tp->ucopy.len = len;
1718
1719 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1720 !(flags & (MSG_PEEK | MSG_TRUNC)));
1721
1722 /* Ugly... If prequeue is not empty, we have to
1723 * process it before releasing socket, otherwise
1724 * order will be broken at second iteration.
1725 * More elegant solution is required!!!
1726 *
1727 * Look: we have the following (pseudo)queues:
1728 *
1729 * 1. packets in flight
1730 * 2. backlog
1731 * 3. prequeue
1732 * 4. receive_queue
1733 *
1734 * Each queue can be processed only if the next ones
1735 * are empty. At this point we have empty receive_queue.
1736 * But prequeue _can_ be not empty after 2nd iteration,
1737 * when we jumped to start of loop because backlog
1738 * processing added something to receive_queue.
1739 * We cannot release_sock(), because backlog contains
1740 * packets arrived _after_ prequeued ones.
1741 *
1742 * Shortly, algorithm is clear --- to process all
1743 * the queues in order. We could make it more directly,
1744 * requeueing packets from backlog to prequeue, if
1745 * is not empty. It is more elegant, but eats cycles,
1746 * unfortunately.
1747 */
1748 if (!skb_queue_empty(&tp->ucopy.prequeue))
1749 goto do_prequeue;
1750
1751 /* __ Set realtime policy in scheduler __ */
1752 }
1753
1754 if (copied >= target) {
1755 /* Do not sleep, just process backlog. */
1756 release_sock(sk);
1757 lock_sock(sk);
1758 } else
1759 sk_wait_data(sk, &timeo);
1760
1761 if (user_recv) {
1762 int chunk;
1763
1764 /* __ Restore normal policy in scheduler __ */
1765
1766 if ((chunk = len - tp->ucopy.len) != 0) {
1767 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1768 len -= chunk;
1769 copied += chunk;
1770 }
1771
1772 if (tp->rcv_nxt == tp->copied_seq &&
1773 !skb_queue_empty(&tp->ucopy.prequeue)) {
1774 do_prequeue:
1775 tcp_prequeue_process(sk);
1776
1777 if ((chunk = len - tp->ucopy.len) != 0) {
1778 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1779 len -= chunk;
1780 copied += chunk;
1781 }
1782 }
1783 }
1784 if ((flags & MSG_PEEK) &&
1785 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1786 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
1787 current->comm,
1788 task_pid_nr(current));
1789 peek_seq = tp->copied_seq;
1790 }
1791 continue;
1792
1793 found_ok_skb:
1794 /* Ok so how much can we use? */
1795 used = skb->len - offset;
1796 if (len < used)
1797 used = len;
1798
1799 /* Do we have urgent data here? */
1800 if (tp->urg_data) {
1801 u32 urg_offset = tp->urg_seq - *seq;
1802 if (urg_offset < used) {
1803 if (!urg_offset) {
1804 if (!sock_flag(sk, SOCK_URGINLINE)) {
1805 ++*seq;
1806 urg_hole++;
1807 offset++;
1808 used--;
1809 if (!used)
1810 goto skip_copy;
1811 }
1812 } else
1813 used = urg_offset;
1814 }
1815 }
1816
1817 if (!(flags & MSG_TRUNC)) {
1818 err = skb_copy_datagram_msg(skb, offset, msg, used);
1819 if (err) {
1820 /* Exception. Bailout! */
1821 if (!copied)
1822 copied = -EFAULT;
1823 break;
1824 }
1825 }
1826
1827 *seq += used;
1828 copied += used;
1829 len -= used;
1830
1831 tcp_rcv_space_adjust(sk);
1832
1833 skip_copy:
1834 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1835 tp->urg_data = 0;
1836 tcp_fast_path_check(sk);
1837 }
1838 if (used + offset < skb->len)
1839 continue;
1840
1841 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
1842 goto found_fin_ok;
1843 if (!(flags & MSG_PEEK))
1844 sk_eat_skb(sk, skb);
1845 continue;
1846
1847 found_fin_ok:
1848 /* Process the FIN. */
1849 ++*seq;
1850 if (!(flags & MSG_PEEK))
1851 sk_eat_skb(sk, skb);
1852 break;
1853 } while (len > 0);
1854
1855 if (user_recv) {
1856 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1857 int chunk;
1858
1859 tp->ucopy.len = copied > 0 ? len : 0;
1860
1861 tcp_prequeue_process(sk);
1862
1863 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1864 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1865 len -= chunk;
1866 copied += chunk;
1867 }
1868 }
1869
1870 tp->ucopy.task = NULL;
1871 tp->ucopy.len = 0;
1872 }
1873
1874 /* According to UNIX98, msg_name/msg_namelen are ignored
1875 * on connected socket. I was just happy when found this 8) --ANK
1876 */
1877
1878 /* Clean up data we have read: This will do ACK frames. */
1879 tcp_cleanup_rbuf(sk, copied);
1880
1881 release_sock(sk);
1882 return copied;
1883
1884 out:
1885 release_sock(sk);
1886 return err;
1887
1888 recv_urg:
1889 err = tcp_recv_urg(sk, msg, len, flags);
1890 goto out;
1891
1892 recv_sndq:
1893 err = tcp_peek_sndq(sk, msg, len);
1894 goto out;
1895 }
1896 EXPORT_SYMBOL(tcp_recvmsg);
1897
1898 void tcp_set_state(struct sock *sk, int state)
1899 {
1900 int oldstate = sk->sk_state;
1901
1902 switch (state) {
1903 case TCP_ESTABLISHED:
1904 if (oldstate != TCP_ESTABLISHED)
1905 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1906 break;
1907
1908 case TCP_CLOSE:
1909 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1910 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1911
1912 sk->sk_prot->unhash(sk);
1913 if (inet_csk(sk)->icsk_bind_hash &&
1914 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1915 inet_put_port(sk);
1916 /* fall through */
1917 default:
1918 if (oldstate == TCP_ESTABLISHED)
1919 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1920 }
1921
1922 /* Change state AFTER socket is unhashed to avoid closed
1923 * socket sitting in hash tables.
1924 */
1925 sk->sk_state = state;
1926
1927 #ifdef STATE_TRACE
1928 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1929 #endif
1930 }
1931 EXPORT_SYMBOL_GPL(tcp_set_state);
1932
1933 /*
1934 * State processing on a close. This implements the state shift for
1935 * sending our FIN frame. Note that we only send a FIN for some
1936 * states. A shutdown() may have already sent the FIN, or we may be
1937 * closed.
1938 */
1939
1940 static const unsigned char new_state[16] = {
1941 /* current state: new state: action: */
1942 /* (Invalid) */ TCP_CLOSE,
1943 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1944 /* TCP_SYN_SENT */ TCP_CLOSE,
1945 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1946 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1947 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1948 /* TCP_TIME_WAIT */ TCP_CLOSE,
1949 /* TCP_CLOSE */ TCP_CLOSE,
1950 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1951 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1952 /* TCP_LISTEN */ TCP_CLOSE,
1953 /* TCP_CLOSING */ TCP_CLOSING,
1954 };
1955
1956 static int tcp_close_state(struct sock *sk)
1957 {
1958 int next = (int)new_state[sk->sk_state];
1959 int ns = next & TCP_STATE_MASK;
1960
1961 tcp_set_state(sk, ns);
1962
1963 return next & TCP_ACTION_FIN;
1964 }
1965
1966 /*
1967 * Shutdown the sending side of a connection. Much like close except
1968 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1969 */
1970
1971 void tcp_shutdown(struct sock *sk, int how)
1972 {
1973 /* We need to grab some memory, and put together a FIN,
1974 * and then put it into the queue to be sent.
1975 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1976 */
1977 if (!(how & SEND_SHUTDOWN))
1978 return;
1979
1980 /* If we've already sent a FIN, or it's a closed state, skip this. */
1981 if ((1 << sk->sk_state) &
1982 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1983 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1984 /* Clear out any half completed packets. FIN if needed. */
1985 if (tcp_close_state(sk))
1986 tcp_send_fin(sk);
1987 }
1988 }
1989 EXPORT_SYMBOL(tcp_shutdown);
1990
1991 bool tcp_check_oom(struct sock *sk, int shift)
1992 {
1993 bool too_many_orphans, out_of_socket_memory;
1994
1995 too_many_orphans = tcp_too_many_orphans(sk, shift);
1996 out_of_socket_memory = tcp_out_of_memory(sk);
1997
1998 if (too_many_orphans)
1999 net_info_ratelimited("too many orphaned sockets\n");
2000 if (out_of_socket_memory)
2001 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
2002 return too_many_orphans || out_of_socket_memory;
2003 }
2004
2005 void tcp_close(struct sock *sk, long timeout)
2006 {
2007 struct sk_buff *skb;
2008 int data_was_unread = 0;
2009 int state;
2010
2011 lock_sock(sk);
2012 sk->sk_shutdown = SHUTDOWN_MASK;
2013
2014 if (sk->sk_state == TCP_LISTEN) {
2015 tcp_set_state(sk, TCP_CLOSE);
2016
2017 /* Special case. */
2018 inet_csk_listen_stop(sk);
2019
2020 goto adjudge_to_death;
2021 }
2022
2023 /* We need to flush the recv. buffs. We do this only on the
2024 * descriptor close, not protocol-sourced closes, because the
2025 * reader process may not have drained the data yet!
2026 */
2027 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2028 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
2029
2030 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2031 len--;
2032 data_was_unread += len;
2033 __kfree_skb(skb);
2034 }
2035
2036 sk_mem_reclaim(sk);
2037
2038 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2039 if (sk->sk_state == TCP_CLOSE)
2040 goto adjudge_to_death;
2041
2042 /* As outlined in RFC 2525, section 2.17, we send a RST here because
2043 * data was lost. To witness the awful effects of the old behavior of
2044 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2045 * GET in an FTP client, suspend the process, wait for the client to
2046 * advertise a zero window, then kill -9 the FTP client, wheee...
2047 * Note: timeout is always zero in such a case.
2048 */
2049 if (unlikely(tcp_sk(sk)->repair)) {
2050 sk->sk_prot->disconnect(sk, 0);
2051 } else if (data_was_unread) {
2052 /* Unread data was tossed, zap the connection. */
2053 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2054 tcp_set_state(sk, TCP_CLOSE);
2055 tcp_send_active_reset(sk, sk->sk_allocation);
2056 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2057 /* Check zero linger _after_ checking for unread data. */
2058 sk->sk_prot->disconnect(sk, 0);
2059 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2060 } else if (tcp_close_state(sk)) {
2061 /* We FIN if the application ate all the data before
2062 * zapping the connection.
2063 */
2064
2065 /* RED-PEN. Formally speaking, we have broken TCP state
2066 * machine. State transitions:
2067 *
2068 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2069 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2070 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2071 *
2072 * are legal only when FIN has been sent (i.e. in window),
2073 * rather than queued out of window. Purists blame.
2074 *
2075 * F.e. "RFC state" is ESTABLISHED,
2076 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2077 *
2078 * The visible declinations are that sometimes
2079 * we enter time-wait state, when it is not required really
2080 * (harmless), do not send active resets, when they are
2081 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2082 * they look as CLOSING or LAST_ACK for Linux)
2083 * Probably, I missed some more holelets.
2084 * --ANK
2085 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2086 * in a single packet! (May consider it later but will
2087 * probably need API support or TCP_CORK SYN-ACK until
2088 * data is written and socket is closed.)
2089 */
2090 tcp_send_fin(sk);
2091 }
2092
2093 sk_stream_wait_close(sk, timeout);
2094
2095 adjudge_to_death:
2096 state = sk->sk_state;
2097 sock_hold(sk);
2098 sock_orphan(sk);
2099
2100 /* It is the last release_sock in its life. It will remove backlog. */
2101 release_sock(sk);
2102
2103
2104 /* Now socket is owned by kernel and we acquire BH lock
2105 to finish close. No need to check for user refs.
2106 */
2107 local_bh_disable();
2108 bh_lock_sock(sk);
2109 WARN_ON(sock_owned_by_user(sk));
2110
2111 percpu_counter_inc(sk->sk_prot->orphan_count);
2112
2113 /* Have we already been destroyed by a softirq or backlog? */
2114 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2115 goto out;
2116
2117 /* This is a (useful) BSD violating of the RFC. There is a
2118 * problem with TCP as specified in that the other end could
2119 * keep a socket open forever with no application left this end.
2120 * We use a 1 minute timeout (about the same as BSD) then kill
2121 * our end. If they send after that then tough - BUT: long enough
2122 * that we won't make the old 4*rto = almost no time - whoops
2123 * reset mistake.
2124 *
2125 * Nope, it was not mistake. It is really desired behaviour
2126 * f.e. on http servers, when such sockets are useless, but
2127 * consume significant resources. Let's do it with special
2128 * linger2 option. --ANK
2129 */
2130
2131 if (sk->sk_state == TCP_FIN_WAIT2) {
2132 struct tcp_sock *tp = tcp_sk(sk);
2133 if (tp->linger2 < 0) {
2134 tcp_set_state(sk, TCP_CLOSE);
2135 tcp_send_active_reset(sk, GFP_ATOMIC);
2136 NET_INC_STATS_BH(sock_net(sk),
2137 LINUX_MIB_TCPABORTONLINGER);
2138 } else {
2139 const int tmo = tcp_fin_time(sk);
2140
2141 if (tmo > TCP_TIMEWAIT_LEN) {
2142 inet_csk_reset_keepalive_timer(sk,
2143 tmo - TCP_TIMEWAIT_LEN);
2144 } else {
2145 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2146 goto out;
2147 }
2148 }
2149 }
2150 if (sk->sk_state != TCP_CLOSE) {
2151 sk_mem_reclaim(sk);
2152 if (tcp_check_oom(sk, 0)) {
2153 tcp_set_state(sk, TCP_CLOSE);
2154 tcp_send_active_reset(sk, GFP_ATOMIC);
2155 NET_INC_STATS_BH(sock_net(sk),
2156 LINUX_MIB_TCPABORTONMEMORY);
2157 }
2158 }
2159
2160 if (sk->sk_state == TCP_CLOSE) {
2161 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2162 /* We could get here with a non-NULL req if the socket is
2163 * aborted (e.g., closed with unread data) before 3WHS
2164 * finishes.
2165 */
2166 if (req != NULL)
2167 reqsk_fastopen_remove(sk, req, false);
2168 inet_csk_destroy_sock(sk);
2169 }
2170 /* Otherwise, socket is reprieved until protocol close. */
2171
2172 out:
2173 bh_unlock_sock(sk);
2174 local_bh_enable();
2175 sock_put(sk);
2176 }
2177 EXPORT_SYMBOL(tcp_close);
2178
2179 /* These states need RST on ABORT according to RFC793 */
2180
2181 static inline bool tcp_need_reset(int state)
2182 {
2183 return (1 << state) &
2184 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2185 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2186 }
2187
2188 int tcp_disconnect(struct sock *sk, int flags)
2189 {
2190 struct inet_sock *inet = inet_sk(sk);
2191 struct inet_connection_sock *icsk = inet_csk(sk);
2192 struct tcp_sock *tp = tcp_sk(sk);
2193 int err = 0;
2194 int old_state = sk->sk_state;
2195
2196 if (old_state != TCP_CLOSE)
2197 tcp_set_state(sk, TCP_CLOSE);
2198
2199 /* ABORT function of RFC793 */
2200 if (old_state == TCP_LISTEN) {
2201 inet_csk_listen_stop(sk);
2202 } else if (unlikely(tp->repair)) {
2203 sk->sk_err = ECONNABORTED;
2204 } else if (tcp_need_reset(old_state) ||
2205 (tp->snd_nxt != tp->write_seq &&
2206 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2207 /* The last check adjusts for discrepancy of Linux wrt. RFC
2208 * states
2209 */
2210 tcp_send_active_reset(sk, gfp_any());
2211 sk->sk_err = ECONNRESET;
2212 } else if (old_state == TCP_SYN_SENT)
2213 sk->sk_err = ECONNRESET;
2214
2215 tcp_clear_xmit_timers(sk);
2216 __skb_queue_purge(&sk->sk_receive_queue);
2217 tcp_write_queue_purge(sk);
2218 __skb_queue_purge(&tp->out_of_order_queue);
2219
2220 inet->inet_dport = 0;
2221
2222 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2223 inet_reset_saddr(sk);
2224
2225 sk->sk_shutdown = 0;
2226 sock_reset_flag(sk, SOCK_DONE);
2227 tp->srtt_us = 0;
2228 if ((tp->write_seq += tp->max_window + 2) == 0)
2229 tp->write_seq = 1;
2230 icsk->icsk_backoff = 0;
2231 tp->snd_cwnd = 2;
2232 icsk->icsk_probes_out = 0;
2233 tp->packets_out = 0;
2234 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2235 tp->snd_cwnd_cnt = 0;
2236 tp->window_clamp = 0;
2237 tcp_set_ca_state(sk, TCP_CA_Open);
2238 tcp_clear_retrans(tp);
2239 inet_csk_delack_init(sk);
2240 tcp_init_send_head(sk);
2241 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2242 __sk_dst_reset(sk);
2243
2244 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2245
2246 sk->sk_error_report(sk);
2247 return err;
2248 }
2249 EXPORT_SYMBOL(tcp_disconnect);
2250
2251 void tcp_sock_destruct(struct sock *sk)
2252 {
2253 inet_sock_destruct(sk);
2254
2255 kfree(inet_csk(sk)->icsk_accept_queue.fastopenq);
2256 }
2257
2258 static inline bool tcp_can_repair_sock(const struct sock *sk)
2259 {
2260 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
2261 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
2262 }
2263
2264 static int tcp_repair_options_est(struct tcp_sock *tp,
2265 struct tcp_repair_opt __user *optbuf, unsigned int len)
2266 {
2267 struct tcp_repair_opt opt;
2268
2269 while (len >= sizeof(opt)) {
2270 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2271 return -EFAULT;
2272
2273 optbuf++;
2274 len -= sizeof(opt);
2275
2276 switch (opt.opt_code) {
2277 case TCPOPT_MSS:
2278 tp->rx_opt.mss_clamp = opt.opt_val;
2279 break;
2280 case TCPOPT_WINDOW:
2281 {
2282 u16 snd_wscale = opt.opt_val & 0xFFFF;
2283 u16 rcv_wscale = opt.opt_val >> 16;
2284
2285 if (snd_wscale > 14 || rcv_wscale > 14)
2286 return -EFBIG;
2287
2288 tp->rx_opt.snd_wscale = snd_wscale;
2289 tp->rx_opt.rcv_wscale = rcv_wscale;
2290 tp->rx_opt.wscale_ok = 1;
2291 }
2292 break;
2293 case TCPOPT_SACK_PERM:
2294 if (opt.opt_val != 0)
2295 return -EINVAL;
2296
2297 tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2298 if (sysctl_tcp_fack)
2299 tcp_enable_fack(tp);
2300 break;
2301 case TCPOPT_TIMESTAMP:
2302 if (opt.opt_val != 0)
2303 return -EINVAL;
2304
2305 tp->rx_opt.tstamp_ok = 1;
2306 break;
2307 }
2308 }
2309
2310 return 0;
2311 }
2312
2313 /*
2314 * Socket option code for TCP.
2315 */
2316 static int do_tcp_setsockopt(struct sock *sk, int level,
2317 int optname, char __user *optval, unsigned int optlen)
2318 {
2319 struct tcp_sock *tp = tcp_sk(sk);
2320 struct inet_connection_sock *icsk = inet_csk(sk);
2321 int val;
2322 int err = 0;
2323
2324 /* These are data/string values, all the others are ints */
2325 switch (optname) {
2326 case TCP_CONGESTION: {
2327 char name[TCP_CA_NAME_MAX];
2328
2329 if (optlen < 1)
2330 return -EINVAL;
2331
2332 val = strncpy_from_user(name, optval,
2333 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2334 if (val < 0)
2335 return -EFAULT;
2336 name[val] = 0;
2337
2338 lock_sock(sk);
2339 err = tcp_set_congestion_control(sk, name);
2340 release_sock(sk);
2341 return err;
2342 }
2343 default:
2344 /* fallthru */
2345 break;
2346 }
2347
2348 if (optlen < sizeof(int))
2349 return -EINVAL;
2350
2351 if (get_user(val, (int __user *)optval))
2352 return -EFAULT;
2353
2354 lock_sock(sk);
2355
2356 switch (optname) {
2357 case TCP_MAXSEG:
2358 /* Values greater than interface MTU won't take effect. However
2359 * at the point when this call is done we typically don't yet
2360 * know which interface is going to be used */
2361 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2362 err = -EINVAL;
2363 break;
2364 }
2365 tp->rx_opt.user_mss = val;
2366 break;
2367
2368 case TCP_NODELAY:
2369 if (val) {
2370 /* TCP_NODELAY is weaker than TCP_CORK, so that
2371 * this option on corked socket is remembered, but
2372 * it is not activated until cork is cleared.
2373 *
2374 * However, when TCP_NODELAY is set we make
2375 * an explicit push, which overrides even TCP_CORK
2376 * for currently queued segments.
2377 */
2378 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2379 tcp_push_pending_frames(sk);
2380 } else {
2381 tp->nonagle &= ~TCP_NAGLE_OFF;
2382 }
2383 break;
2384
2385 case TCP_THIN_LINEAR_TIMEOUTS:
2386 if (val < 0 || val > 1)
2387 err = -EINVAL;
2388 else
2389 tp->thin_lto = val;
2390 break;
2391
2392 case TCP_THIN_DUPACK:
2393 if (val < 0 || val > 1)
2394 err = -EINVAL;
2395 else {
2396 tp->thin_dupack = val;
2397 if (tp->thin_dupack)
2398 tcp_disable_early_retrans(tp);
2399 }
2400 break;
2401
2402 case TCP_REPAIR:
2403 if (!tcp_can_repair_sock(sk))
2404 err = -EPERM;
2405 else if (val == 1) {
2406 tp->repair = 1;
2407 sk->sk_reuse = SK_FORCE_REUSE;
2408 tp->repair_queue = TCP_NO_QUEUE;
2409 } else if (val == 0) {
2410 tp->repair = 0;
2411 sk->sk_reuse = SK_NO_REUSE;
2412 tcp_send_window_probe(sk);
2413 } else
2414 err = -EINVAL;
2415
2416 break;
2417
2418 case TCP_REPAIR_QUEUE:
2419 if (!tp->repair)
2420 err = -EPERM;
2421 else if (val < TCP_QUEUES_NR)
2422 tp->repair_queue = val;
2423 else
2424 err = -EINVAL;
2425 break;
2426
2427 case TCP_QUEUE_SEQ:
2428 if (sk->sk_state != TCP_CLOSE)
2429 err = -EPERM;
2430 else if (tp->repair_queue == TCP_SEND_QUEUE)
2431 tp->write_seq = val;
2432 else if (tp->repair_queue == TCP_RECV_QUEUE)
2433 tp->rcv_nxt = val;
2434 else
2435 err = -EINVAL;
2436 break;
2437
2438 case TCP_REPAIR_OPTIONS:
2439 if (!tp->repair)
2440 err = -EINVAL;
2441 else if (sk->sk_state == TCP_ESTABLISHED)
2442 err = tcp_repair_options_est(tp,
2443 (struct tcp_repair_opt __user *)optval,
2444 optlen);
2445 else
2446 err = -EPERM;
2447 break;
2448
2449 case TCP_CORK:
2450 /* When set indicates to always queue non-full frames.
2451 * Later the user clears this option and we transmit
2452 * any pending partial frames in the queue. This is
2453 * meant to be used alongside sendfile() to get properly
2454 * filled frames when the user (for example) must write
2455 * out headers with a write() call first and then use
2456 * sendfile to send out the data parts.
2457 *
2458 * TCP_CORK can be set together with TCP_NODELAY and it is
2459 * stronger than TCP_NODELAY.
2460 */
2461 if (val) {
2462 tp->nonagle |= TCP_NAGLE_CORK;
2463 } else {
2464 tp->nonagle &= ~TCP_NAGLE_CORK;
2465 if (tp->nonagle&TCP_NAGLE_OFF)
2466 tp->nonagle |= TCP_NAGLE_PUSH;
2467 tcp_push_pending_frames(sk);
2468 }
2469 break;
2470
2471 case TCP_KEEPIDLE:
2472 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2473 err = -EINVAL;
2474 else {
2475 tp->keepalive_time = val * HZ;
2476 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2477 !((1 << sk->sk_state) &
2478 (TCPF_CLOSE | TCPF_LISTEN))) {
2479 u32 elapsed = keepalive_time_elapsed(tp);
2480 if (tp->keepalive_time > elapsed)
2481 elapsed = tp->keepalive_time - elapsed;
2482 else
2483 elapsed = 0;
2484 inet_csk_reset_keepalive_timer(sk, elapsed);
2485 }
2486 }
2487 break;
2488 case TCP_KEEPINTVL:
2489 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2490 err = -EINVAL;
2491 else
2492 tp->keepalive_intvl = val * HZ;
2493 break;
2494 case TCP_KEEPCNT:
2495 if (val < 1 || val > MAX_TCP_KEEPCNT)
2496 err = -EINVAL;
2497 else
2498 tp->keepalive_probes = val;
2499 break;
2500 case TCP_SYNCNT:
2501 if (val < 1 || val > MAX_TCP_SYNCNT)
2502 err = -EINVAL;
2503 else
2504 icsk->icsk_syn_retries = val;
2505 break;
2506
2507 case TCP_LINGER2:
2508 if (val < 0)
2509 tp->linger2 = -1;
2510 else if (val > sysctl_tcp_fin_timeout / HZ)
2511 tp->linger2 = 0;
2512 else
2513 tp->linger2 = val * HZ;
2514 break;
2515
2516 case TCP_DEFER_ACCEPT:
2517 /* Translate value in seconds to number of retransmits */
2518 icsk->icsk_accept_queue.rskq_defer_accept =
2519 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2520 TCP_RTO_MAX / HZ);
2521 break;
2522
2523 case TCP_WINDOW_CLAMP:
2524 if (!val) {
2525 if (sk->sk_state != TCP_CLOSE) {
2526 err = -EINVAL;
2527 break;
2528 }
2529 tp->window_clamp = 0;
2530 } else
2531 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2532 SOCK_MIN_RCVBUF / 2 : val;
2533 break;
2534
2535 case TCP_QUICKACK:
2536 if (!val) {
2537 icsk->icsk_ack.pingpong = 1;
2538 } else {
2539 icsk->icsk_ack.pingpong = 0;
2540 if ((1 << sk->sk_state) &
2541 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2542 inet_csk_ack_scheduled(sk)) {
2543 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2544 tcp_cleanup_rbuf(sk, 1);
2545 if (!(val & 1))
2546 icsk->icsk_ack.pingpong = 1;
2547 }
2548 }
2549 break;
2550
2551 #ifdef CONFIG_TCP_MD5SIG
2552 case TCP_MD5SIG:
2553 /* Read the IP->Key mappings from userspace */
2554 err = tp->af_specific->md5_parse(sk, optval, optlen);
2555 break;
2556 #endif
2557 case TCP_USER_TIMEOUT:
2558 /* Cap the max time in ms TCP will retry or probe the window
2559 * before giving up and aborting (ETIMEDOUT) a connection.
2560 */
2561 if (val < 0)
2562 err = -EINVAL;
2563 else
2564 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2565 break;
2566
2567 case TCP_FASTOPEN:
2568 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2569 TCPF_LISTEN)))
2570 err = fastopen_init_queue(sk, val);
2571 else
2572 err = -EINVAL;
2573 break;
2574 case TCP_TIMESTAMP:
2575 if (!tp->repair)
2576 err = -EPERM;
2577 else
2578 tp->tsoffset = val - tcp_time_stamp;
2579 break;
2580 case TCP_NOTSENT_LOWAT:
2581 tp->notsent_lowat = val;
2582 sk->sk_write_space(sk);
2583 break;
2584 default:
2585 err = -ENOPROTOOPT;
2586 break;
2587 }
2588
2589 release_sock(sk);
2590 return err;
2591 }
2592
2593 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2594 unsigned int optlen)
2595 {
2596 const struct inet_connection_sock *icsk = inet_csk(sk);
2597
2598 if (level != SOL_TCP)
2599 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2600 optval, optlen);
2601 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2602 }
2603 EXPORT_SYMBOL(tcp_setsockopt);
2604
2605 #ifdef CONFIG_COMPAT
2606 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2607 char __user *optval, unsigned int optlen)
2608 {
2609 if (level != SOL_TCP)
2610 return inet_csk_compat_setsockopt(sk, level, optname,
2611 optval, optlen);
2612 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2613 }
2614 EXPORT_SYMBOL(compat_tcp_setsockopt);
2615 #endif
2616
2617 /* Return information about state of tcp endpoint in API format. */
2618 void tcp_get_info(const struct sock *sk, struct tcp_info *info)
2619 {
2620 const struct tcp_sock *tp = tcp_sk(sk);
2621 const struct inet_connection_sock *icsk = inet_csk(sk);
2622 u32 now = tcp_time_stamp;
2623
2624 memset(info, 0, sizeof(*info));
2625
2626 info->tcpi_state = sk->sk_state;
2627 info->tcpi_ca_state = icsk->icsk_ca_state;
2628 info->tcpi_retransmits = icsk->icsk_retransmits;
2629 info->tcpi_probes = icsk->icsk_probes_out;
2630 info->tcpi_backoff = icsk->icsk_backoff;
2631
2632 if (tp->rx_opt.tstamp_ok)
2633 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2634 if (tcp_is_sack(tp))
2635 info->tcpi_options |= TCPI_OPT_SACK;
2636 if (tp->rx_opt.wscale_ok) {
2637 info->tcpi_options |= TCPI_OPT_WSCALE;
2638 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2639 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2640 }
2641
2642 if (tp->ecn_flags & TCP_ECN_OK)
2643 info->tcpi_options |= TCPI_OPT_ECN;
2644 if (tp->ecn_flags & TCP_ECN_SEEN)
2645 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2646 if (tp->syn_data_acked)
2647 info->tcpi_options |= TCPI_OPT_SYN_DATA;
2648
2649 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2650 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2651 info->tcpi_snd_mss = tp->mss_cache;
2652 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2653
2654 if (sk->sk_state == TCP_LISTEN) {
2655 info->tcpi_unacked = sk->sk_ack_backlog;
2656 info->tcpi_sacked = sk->sk_max_ack_backlog;
2657 } else {
2658 info->tcpi_unacked = tp->packets_out;
2659 info->tcpi_sacked = tp->sacked_out;
2660 }
2661 info->tcpi_lost = tp->lost_out;
2662 info->tcpi_retrans = tp->retrans_out;
2663 info->tcpi_fackets = tp->fackets_out;
2664
2665 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2666 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2667 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2668
2669 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2670 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2671 info->tcpi_rtt = tp->srtt_us >> 3;
2672 info->tcpi_rttvar = tp->mdev_us >> 2;
2673 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2674 info->tcpi_snd_cwnd = tp->snd_cwnd;
2675 info->tcpi_advmss = tp->advmss;
2676 info->tcpi_reordering = tp->reordering;
2677
2678 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2679 info->tcpi_rcv_space = tp->rcvq_space.space;
2680
2681 info->tcpi_total_retrans = tp->total_retrans;
2682
2683 info->tcpi_pacing_rate = sk->sk_pacing_rate != ~0U ?
2684 sk->sk_pacing_rate : ~0ULL;
2685 info->tcpi_max_pacing_rate = sk->sk_max_pacing_rate != ~0U ?
2686 sk->sk_max_pacing_rate : ~0ULL;
2687 }
2688 EXPORT_SYMBOL_GPL(tcp_get_info);
2689
2690 static int do_tcp_getsockopt(struct sock *sk, int level,
2691 int optname, char __user *optval, int __user *optlen)
2692 {
2693 struct inet_connection_sock *icsk = inet_csk(sk);
2694 struct tcp_sock *tp = tcp_sk(sk);
2695 int val, len;
2696
2697 if (get_user(len, optlen))
2698 return -EFAULT;
2699
2700 len = min_t(unsigned int, len, sizeof(int));
2701
2702 if (len < 0)
2703 return -EINVAL;
2704
2705 switch (optname) {
2706 case TCP_MAXSEG:
2707 val = tp->mss_cache;
2708 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2709 val = tp->rx_opt.user_mss;
2710 if (tp->repair)
2711 val = tp->rx_opt.mss_clamp;
2712 break;
2713 case TCP_NODELAY:
2714 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2715 break;
2716 case TCP_CORK:
2717 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2718 break;
2719 case TCP_KEEPIDLE:
2720 val = keepalive_time_when(tp) / HZ;
2721 break;
2722 case TCP_KEEPINTVL:
2723 val = keepalive_intvl_when(tp) / HZ;
2724 break;
2725 case TCP_KEEPCNT:
2726 val = keepalive_probes(tp);
2727 break;
2728 case TCP_SYNCNT:
2729 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2730 break;
2731 case TCP_LINGER2:
2732 val = tp->linger2;
2733 if (val >= 0)
2734 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2735 break;
2736 case TCP_DEFER_ACCEPT:
2737 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2738 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2739 break;
2740 case TCP_WINDOW_CLAMP:
2741 val = tp->window_clamp;
2742 break;
2743 case TCP_INFO: {
2744 struct tcp_info info;
2745
2746 if (get_user(len, optlen))
2747 return -EFAULT;
2748
2749 tcp_get_info(sk, &info);
2750
2751 len = min_t(unsigned int, len, sizeof(info));
2752 if (put_user(len, optlen))
2753 return -EFAULT;
2754 if (copy_to_user(optval, &info, len))
2755 return -EFAULT;
2756 return 0;
2757 }
2758 case TCP_QUICKACK:
2759 val = !icsk->icsk_ack.pingpong;
2760 break;
2761
2762 case TCP_CONGESTION:
2763 if (get_user(len, optlen))
2764 return -EFAULT;
2765 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2766 if (put_user(len, optlen))
2767 return -EFAULT;
2768 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2769 return -EFAULT;
2770 return 0;
2771
2772 case TCP_THIN_LINEAR_TIMEOUTS:
2773 val = tp->thin_lto;
2774 break;
2775 case TCP_THIN_DUPACK:
2776 val = tp->thin_dupack;
2777 break;
2778
2779 case TCP_REPAIR:
2780 val = tp->repair;
2781 break;
2782
2783 case TCP_REPAIR_QUEUE:
2784 if (tp->repair)
2785 val = tp->repair_queue;
2786 else
2787 return -EINVAL;
2788 break;
2789
2790 case TCP_QUEUE_SEQ:
2791 if (tp->repair_queue == TCP_SEND_QUEUE)
2792 val = tp->write_seq;
2793 else if (tp->repair_queue == TCP_RECV_QUEUE)
2794 val = tp->rcv_nxt;
2795 else
2796 return -EINVAL;
2797 break;
2798
2799 case TCP_USER_TIMEOUT:
2800 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2801 break;
2802
2803 case TCP_FASTOPEN:
2804 if (icsk->icsk_accept_queue.fastopenq != NULL)
2805 val = icsk->icsk_accept_queue.fastopenq->max_qlen;
2806 else
2807 val = 0;
2808 break;
2809
2810 case TCP_TIMESTAMP:
2811 val = tcp_time_stamp + tp->tsoffset;
2812 break;
2813 case TCP_NOTSENT_LOWAT:
2814 val = tp->notsent_lowat;
2815 break;
2816 default:
2817 return -ENOPROTOOPT;
2818 }
2819
2820 if (put_user(len, optlen))
2821 return -EFAULT;
2822 if (copy_to_user(optval, &val, len))
2823 return -EFAULT;
2824 return 0;
2825 }
2826
2827 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2828 int __user *optlen)
2829 {
2830 struct inet_connection_sock *icsk = inet_csk(sk);
2831
2832 if (level != SOL_TCP)
2833 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2834 optval, optlen);
2835 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2836 }
2837 EXPORT_SYMBOL(tcp_getsockopt);
2838
2839 #ifdef CONFIG_COMPAT
2840 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2841 char __user *optval, int __user *optlen)
2842 {
2843 if (level != SOL_TCP)
2844 return inet_csk_compat_getsockopt(sk, level, optname,
2845 optval, optlen);
2846 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2847 }
2848 EXPORT_SYMBOL(compat_tcp_getsockopt);
2849 #endif
2850
2851 #ifdef CONFIG_TCP_MD5SIG
2852 static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
2853 static DEFINE_MUTEX(tcp_md5sig_mutex);
2854 static bool tcp_md5sig_pool_populated = false;
2855
2856 static void __tcp_alloc_md5sig_pool(void)
2857 {
2858 int cpu;
2859
2860 for_each_possible_cpu(cpu) {
2861 if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) {
2862 struct crypto_hash *hash;
2863
2864 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2865 if (IS_ERR_OR_NULL(hash))
2866 return;
2867 per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm = hash;
2868 }
2869 }
2870 /* before setting tcp_md5sig_pool_populated, we must commit all writes
2871 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
2872 */
2873 smp_wmb();
2874 tcp_md5sig_pool_populated = true;
2875 }
2876
2877 bool tcp_alloc_md5sig_pool(void)
2878 {
2879 if (unlikely(!tcp_md5sig_pool_populated)) {
2880 mutex_lock(&tcp_md5sig_mutex);
2881
2882 if (!tcp_md5sig_pool_populated)
2883 __tcp_alloc_md5sig_pool();
2884
2885 mutex_unlock(&tcp_md5sig_mutex);
2886 }
2887 return tcp_md5sig_pool_populated;
2888 }
2889 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2890
2891
2892 /**
2893 * tcp_get_md5sig_pool - get md5sig_pool for this user
2894 *
2895 * We use percpu structure, so if we succeed, we exit with preemption
2896 * and BH disabled, to make sure another thread or softirq handling
2897 * wont try to get same context.
2898 */
2899 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2900 {
2901 local_bh_disable();
2902
2903 if (tcp_md5sig_pool_populated) {
2904 /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
2905 smp_rmb();
2906 return this_cpu_ptr(&tcp_md5sig_pool);
2907 }
2908 local_bh_enable();
2909 return NULL;
2910 }
2911 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2912
2913 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2914 const struct tcphdr *th)
2915 {
2916 struct scatterlist sg;
2917 struct tcphdr hdr;
2918 int err;
2919
2920 /* We are not allowed to change tcphdr, make a local copy */
2921 memcpy(&hdr, th, sizeof(hdr));
2922 hdr.check = 0;
2923
2924 /* options aren't included in the hash */
2925 sg_init_one(&sg, &hdr, sizeof(hdr));
2926 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
2927 return err;
2928 }
2929 EXPORT_SYMBOL(tcp_md5_hash_header);
2930
2931 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2932 const struct sk_buff *skb, unsigned int header_len)
2933 {
2934 struct scatterlist sg;
2935 const struct tcphdr *tp = tcp_hdr(skb);
2936 struct hash_desc *desc = &hp->md5_desc;
2937 unsigned int i;
2938 const unsigned int head_data_len = skb_headlen(skb) > header_len ?
2939 skb_headlen(skb) - header_len : 0;
2940 const struct skb_shared_info *shi = skb_shinfo(skb);
2941 struct sk_buff *frag_iter;
2942
2943 sg_init_table(&sg, 1);
2944
2945 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2946 if (crypto_hash_update(desc, &sg, head_data_len))
2947 return 1;
2948
2949 for (i = 0; i < shi->nr_frags; ++i) {
2950 const struct skb_frag_struct *f = &shi->frags[i];
2951 unsigned int offset = f->page_offset;
2952 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
2953
2954 sg_set_page(&sg, page, skb_frag_size(f),
2955 offset_in_page(offset));
2956 if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
2957 return 1;
2958 }
2959
2960 skb_walk_frags(skb, frag_iter)
2961 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
2962 return 1;
2963
2964 return 0;
2965 }
2966 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
2967
2968 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
2969 {
2970 struct scatterlist sg;
2971
2972 sg_init_one(&sg, key->key, key->keylen);
2973 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
2974 }
2975 EXPORT_SYMBOL(tcp_md5_hash_key);
2976
2977 #endif
2978
2979 void tcp_done(struct sock *sk)
2980 {
2981 struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2982
2983 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2984 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
2985
2986 tcp_set_state(sk, TCP_CLOSE);
2987 tcp_clear_xmit_timers(sk);
2988 if (req != NULL)
2989 reqsk_fastopen_remove(sk, req, false);
2990
2991 sk->sk_shutdown = SHUTDOWN_MASK;
2992
2993 if (!sock_flag(sk, SOCK_DEAD))
2994 sk->sk_state_change(sk);
2995 else
2996 inet_csk_destroy_sock(sk);
2997 }
2998 EXPORT_SYMBOL_GPL(tcp_done);
2999
3000 extern struct tcp_congestion_ops tcp_reno;
3001
3002 static __initdata unsigned long thash_entries;
3003 static int __init set_thash_entries(char *str)
3004 {
3005 ssize_t ret;
3006
3007 if (!str)
3008 return 0;
3009
3010 ret = kstrtoul(str, 0, &thash_entries);
3011 if (ret)
3012 return 0;
3013
3014 return 1;
3015 }
3016 __setup("thash_entries=", set_thash_entries);
3017
3018 static void __init tcp_init_mem(void)
3019 {
3020 unsigned long limit = nr_free_buffer_pages() / 8;
3021 limit = max(limit, 128UL);
3022 sysctl_tcp_mem[0] = limit / 4 * 3;
3023 sysctl_tcp_mem[1] = limit;
3024 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3025 }
3026
3027 void __init tcp_init(void)
3028 {
3029 struct sk_buff *skb = NULL;
3030 unsigned long limit;
3031 int max_rshare, max_wshare, cnt;
3032 unsigned int i;
3033
3034 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3035
3036 percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
3037 percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3038 tcp_hashinfo.bind_bucket_cachep =
3039 kmem_cache_create("tcp_bind_bucket",
3040 sizeof(struct inet_bind_bucket), 0,
3041 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3042
3043 /* Size and allocate the main established and bind bucket
3044 * hash tables.
3045 *
3046 * The methodology is similar to that of the buffer cache.
3047 */
3048 tcp_hashinfo.ehash =
3049 alloc_large_system_hash("TCP established",
3050 sizeof(struct inet_ehash_bucket),
3051 thash_entries,
3052 17, /* one slot per 128 KB of memory */
3053 0,
3054 NULL,
3055 &tcp_hashinfo.ehash_mask,
3056 0,
3057 thash_entries ? 0 : 512 * 1024);
3058 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3059 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3060
3061 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3062 panic("TCP: failed to alloc ehash_locks");
3063 tcp_hashinfo.bhash =
3064 alloc_large_system_hash("TCP bind",
3065 sizeof(struct inet_bind_hashbucket),
3066 tcp_hashinfo.ehash_mask + 1,
3067 17, /* one slot per 128 KB of memory */
3068 0,
3069 &tcp_hashinfo.bhash_size,
3070 NULL,
3071 0,
3072 64 * 1024);
3073 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3074 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3075 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3076 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3077 }
3078
3079
3080 cnt = tcp_hashinfo.ehash_mask + 1;
3081
3082 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3083 sysctl_tcp_max_orphans = cnt / 2;
3084 sysctl_max_syn_backlog = max(128, cnt / 256);
3085
3086 tcp_init_mem();
3087 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3088 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3089 max_wshare = min(4UL*1024*1024, limit);
3090 max_rshare = min(6UL*1024*1024, limit);
3091
3092 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3093 sysctl_tcp_wmem[1] = 16*1024;
3094 sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3095
3096 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3097 sysctl_tcp_rmem[1] = 87380;
3098 sysctl_tcp_rmem[2] = max(87380, max_rshare);
3099
3100 pr_info("Hash tables configured (established %u bind %u)\n",
3101 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3102
3103 tcp_metrics_init();
3104 BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
3105 tcp_tasklet_init();
3106 }
Linux kernel - Deliverables
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