Loading...
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#include <linux/kernel.h>
249#include <linux/module.h>
250#include <linux/types.h>
251#include <linux/fcntl.h>
252#include <linux/poll.h>
253#include <linux/init.h>
254#include <linux/fs.h>
255#include <linux/skbuff.h>
256#include <linux/scatterlist.h>
257#include <linux/splice.h>
258#include <linux/net.h>
259#include <linux/socket.h>
260#include <linux/random.h>
261#include <linux/bootmem.h>
262#include <linux/highmem.h>
263#include <linux/swap.h>
264#include <linux/cache.h>
265#include <linux/err.h>
266#include <linux/crypto.h>
267#include <linux/time.h>
268#include <linux/slab.h>
269
270#include <net/icmp.h>
271#include <net/tcp.h>
272#include <net/xfrm.h>
273#include <net/ip.h>
274#include <net/netdma.h>
275#include <net/sock.h>
276
277#include <asm/uaccess.h>
278#include <asm/ioctls.h>
279
280int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
281
282struct percpu_counter tcp_orphan_count;
283EXPORT_SYMBOL_GPL(tcp_orphan_count);
284
285long sysctl_tcp_mem[3] __read_mostly;
286int sysctl_tcp_wmem[3] __read_mostly;
287int sysctl_tcp_rmem[3] __read_mostly;
288
289EXPORT_SYMBOL(sysctl_tcp_mem);
290EXPORT_SYMBOL(sysctl_tcp_rmem);
291EXPORT_SYMBOL(sysctl_tcp_wmem);
292
293atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
294EXPORT_SYMBOL(tcp_memory_allocated);
295
296/*
297 * Current number of TCP sockets.
298 */
299struct percpu_counter tcp_sockets_allocated;
300EXPORT_SYMBOL(tcp_sockets_allocated);
301
302/*
303 * TCP splice context
304 */
305struct tcp_splice_state {
306 struct pipe_inode_info *pipe;
307 size_t len;
308 unsigned int flags;
309};
310
311/*
312 * Pressure flag: try to collapse.
313 * Technical note: it is used by multiple contexts non atomically.
314 * All the __sk_mem_schedule() is of this nature: accounting
315 * is strict, actions are advisory and have some latency.
316 */
317int tcp_memory_pressure __read_mostly;
318EXPORT_SYMBOL(tcp_memory_pressure);
319
320void tcp_enter_memory_pressure(struct sock *sk)
321{
322 if (!tcp_memory_pressure) {
323 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
324 tcp_memory_pressure = 1;
325 }
326}
327EXPORT_SYMBOL(tcp_enter_memory_pressure);
328
329/* Convert seconds to retransmits based on initial and max timeout */
330static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
331{
332 u8 res = 0;
333
334 if (seconds > 0) {
335 int period = timeout;
336
337 res = 1;
338 while (seconds > period && res < 255) {
339 res++;
340 timeout <<= 1;
341 if (timeout > rto_max)
342 timeout = rto_max;
343 period += timeout;
344 }
345 }
346 return res;
347}
348
349/* Convert retransmits to seconds based on initial and max timeout */
350static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
351{
352 int period = 0;
353
354 if (retrans > 0) {
355 period = timeout;
356 while (--retrans) {
357 timeout <<= 1;
358 if (timeout > rto_max)
359 timeout = rto_max;
360 period += timeout;
361 }
362 }
363 return period;
364}
365
366/*
367 * Wait for a TCP event.
368 *
369 * Note that we don't need to lock the socket, as the upper poll layers
370 * take care of normal races (between the test and the event) and we don't
371 * go look at any of the socket buffers directly.
372 */
373unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
374{
375 unsigned int mask;
376 struct sock *sk = sock->sk;
377 struct tcp_sock *tp = tcp_sk(sk);
378
379 sock_poll_wait(file, sk_sleep(sk), wait);
380 if (sk->sk_state == TCP_LISTEN)
381 return inet_csk_listen_poll(sk);
382
383 /* Socket is not locked. We are protected from async events
384 * by poll logic and correct handling of state changes
385 * made by other threads is impossible in any case.
386 */
387
388 mask = 0;
389
390 /*
391 * POLLHUP is certainly not done right. But poll() doesn't
392 * have a notion of HUP in just one direction, and for a
393 * socket the read side is more interesting.
394 *
395 * Some poll() documentation says that POLLHUP is incompatible
396 * with the POLLOUT/POLLWR flags, so somebody should check this
397 * all. But careful, it tends to be safer to return too many
398 * bits than too few, and you can easily break real applications
399 * if you don't tell them that something has hung up!
400 *
401 * Check-me.
402 *
403 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
404 * our fs/select.c). It means that after we received EOF,
405 * poll always returns immediately, making impossible poll() on write()
406 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
407 * if and only if shutdown has been made in both directions.
408 * Actually, it is interesting to look how Solaris and DUX
409 * solve this dilemma. I would prefer, if POLLHUP were maskable,
410 * then we could set it on SND_SHUTDOWN. BTW examples given
411 * in Stevens' books assume exactly this behaviour, it explains
412 * why POLLHUP is incompatible with POLLOUT. --ANK
413 *
414 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
415 * blocking on fresh not-connected or disconnected socket. --ANK
416 */
417 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
418 mask |= POLLHUP;
419 if (sk->sk_shutdown & RCV_SHUTDOWN)
420 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
421
422 /* Connected? */
423 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
424 int target = sock_rcvlowat(sk, 0, INT_MAX);
425
426 if (tp->urg_seq == tp->copied_seq &&
427 !sock_flag(sk, SOCK_URGINLINE) &&
428 tp->urg_data)
429 target++;
430
431 /* Potential race condition. If read of tp below will
432 * escape above sk->sk_state, we can be illegally awaken
433 * in SYN_* states. */
434 if (tp->rcv_nxt - tp->copied_seq >= target)
435 mask |= POLLIN | POLLRDNORM;
436
437 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
438 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
439 mask |= POLLOUT | POLLWRNORM;
440 } else { /* send SIGIO later */
441 set_bit(SOCK_ASYNC_NOSPACE,
442 &sk->sk_socket->flags);
443 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
444
445 /* Race breaker. If space is freed after
446 * wspace test but before the flags are set,
447 * IO signal will be lost.
448 */
449 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
450 mask |= POLLOUT | POLLWRNORM;
451 }
452 } else
453 mask |= POLLOUT | POLLWRNORM;
454
455 if (tp->urg_data & TCP_URG_VALID)
456 mask |= POLLPRI;
457 }
458 /* This barrier is coupled with smp_wmb() in tcp_reset() */
459 smp_rmb();
460 if (sk->sk_err)
461 mask |= POLLERR;
462
463 return mask;
464}
465EXPORT_SYMBOL(tcp_poll);
466
467int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
468{
469 struct tcp_sock *tp = tcp_sk(sk);
470 int answ;
471
472 switch (cmd) {
473 case SIOCINQ:
474 if (sk->sk_state == TCP_LISTEN)
475 return -EINVAL;
476
477 lock_sock(sk);
478 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
479 answ = 0;
480 else if (sock_flag(sk, SOCK_URGINLINE) ||
481 !tp->urg_data ||
482 before(tp->urg_seq, tp->copied_seq) ||
483 !before(tp->urg_seq, tp->rcv_nxt)) {
484 struct sk_buff *skb;
485
486 answ = tp->rcv_nxt - tp->copied_seq;
487
488 /* Subtract 1, if FIN is in queue. */
489 skb = skb_peek_tail(&sk->sk_receive_queue);
490 if (answ && skb)
491 answ -= tcp_hdr(skb)->fin;
492 } else
493 answ = tp->urg_seq - tp->copied_seq;
494 release_sock(sk);
495 break;
496 case SIOCATMARK:
497 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
498 break;
499 case SIOCOUTQ:
500 if (sk->sk_state == TCP_LISTEN)
501 return -EINVAL;
502
503 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
504 answ = 0;
505 else
506 answ = tp->write_seq - tp->snd_una;
507 break;
508 case SIOCOUTQNSD:
509 if (sk->sk_state == TCP_LISTEN)
510 return -EINVAL;
511
512 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
513 answ = 0;
514 else
515 answ = tp->write_seq - tp->snd_nxt;
516 break;
517 default:
518 return -ENOIOCTLCMD;
519 }
520
521 return put_user(answ, (int __user *)arg);
522}
523EXPORT_SYMBOL(tcp_ioctl);
524
525static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
526{
527 TCP_SKB_CB(skb)->flags |= TCPHDR_PSH;
528 tp->pushed_seq = tp->write_seq;
529}
530
531static inline int forced_push(struct tcp_sock *tp)
532{
533 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
534}
535
536static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
537{
538 struct tcp_sock *tp = tcp_sk(sk);
539 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
540
541 skb->csum = 0;
542 tcb->seq = tcb->end_seq = tp->write_seq;
543 tcb->flags = TCPHDR_ACK;
544 tcb->sacked = 0;
545 skb_header_release(skb);
546 tcp_add_write_queue_tail(sk, skb);
547 sk->sk_wmem_queued += skb->truesize;
548 sk_mem_charge(sk, skb->truesize);
549 if (tp->nonagle & TCP_NAGLE_PUSH)
550 tp->nonagle &= ~TCP_NAGLE_PUSH;
551}
552
553static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
554{
555 if (flags & MSG_OOB)
556 tp->snd_up = tp->write_seq;
557}
558
559static inline void tcp_push(struct sock *sk, int flags, int mss_now,
560 int nonagle)
561{
562 if (tcp_send_head(sk)) {
563 struct tcp_sock *tp = tcp_sk(sk);
564
565 if (!(flags & MSG_MORE) || forced_push(tp))
566 tcp_mark_push(tp, tcp_write_queue_tail(sk));
567
568 tcp_mark_urg(tp, flags);
569 __tcp_push_pending_frames(sk, mss_now,
570 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
571 }
572}
573
574static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
575 unsigned int offset, size_t len)
576{
577 struct tcp_splice_state *tss = rd_desc->arg.data;
578 int ret;
579
580 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
581 tss->flags);
582 if (ret > 0)
583 rd_desc->count -= ret;
584 return ret;
585}
586
587static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
588{
589 /* Store TCP splice context information in read_descriptor_t. */
590 read_descriptor_t rd_desc = {
591 .arg.data = tss,
592 .count = tss->len,
593 };
594
595 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
596}
597
598/**
599 * tcp_splice_read - splice data from TCP socket to a pipe
600 * @sock: socket to splice from
601 * @ppos: position (not valid)
602 * @pipe: pipe to splice to
603 * @len: number of bytes to splice
604 * @flags: splice modifier flags
605 *
606 * Description:
607 * Will read pages from given socket and fill them into a pipe.
608 *
609 **/
610ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
611 struct pipe_inode_info *pipe, size_t len,
612 unsigned int flags)
613{
614 struct sock *sk = sock->sk;
615 struct tcp_splice_state tss = {
616 .pipe = pipe,
617 .len = len,
618 .flags = flags,
619 };
620 long timeo;
621 ssize_t spliced;
622 int ret;
623
624 sock_rps_record_flow(sk);
625 /*
626 * We can't seek on a socket input
627 */
628 if (unlikely(*ppos))
629 return -ESPIPE;
630
631 ret = spliced = 0;
632
633 lock_sock(sk);
634
635 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
636 while (tss.len) {
637 ret = __tcp_splice_read(sk, &tss);
638 if (ret < 0)
639 break;
640 else if (!ret) {
641 if (spliced)
642 break;
643 if (sock_flag(sk, SOCK_DONE))
644 break;
645 if (sk->sk_err) {
646 ret = sock_error(sk);
647 break;
648 }
649 if (sk->sk_shutdown & RCV_SHUTDOWN)
650 break;
651 if (sk->sk_state == TCP_CLOSE) {
652 /*
653 * This occurs when user tries to read
654 * from never connected socket.
655 */
656 if (!sock_flag(sk, SOCK_DONE))
657 ret = -ENOTCONN;
658 break;
659 }
660 if (!timeo) {
661 ret = -EAGAIN;
662 break;
663 }
664 sk_wait_data(sk, &timeo);
665 if (signal_pending(current)) {
666 ret = sock_intr_errno(timeo);
667 break;
668 }
669 continue;
670 }
671 tss.len -= ret;
672 spliced += ret;
673
674 if (!timeo)
675 break;
676 release_sock(sk);
677 lock_sock(sk);
678
679 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
680 (sk->sk_shutdown & RCV_SHUTDOWN) ||
681 signal_pending(current))
682 break;
683 }
684
685 release_sock(sk);
686
687 if (spliced)
688 return spliced;
689
690 return ret;
691}
692EXPORT_SYMBOL(tcp_splice_read);
693
694struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
695{
696 struct sk_buff *skb;
697
698 /* The TCP header must be at least 32-bit aligned. */
699 size = ALIGN(size, 4);
700
701 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
702 if (skb) {
703 if (sk_wmem_schedule(sk, skb->truesize)) {
704 /*
705 * Make sure that we have exactly size bytes
706 * available to the caller, no more, no less.
707 */
708 skb_reserve(skb, skb_tailroom(skb) - size);
709 return skb;
710 }
711 __kfree_skb(skb);
712 } else {
713 sk->sk_prot->enter_memory_pressure(sk);
714 sk_stream_moderate_sndbuf(sk);
715 }
716 return NULL;
717}
718
719static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
720 int large_allowed)
721{
722 struct tcp_sock *tp = tcp_sk(sk);
723 u32 xmit_size_goal, old_size_goal;
724
725 xmit_size_goal = mss_now;
726
727 if (large_allowed && sk_can_gso(sk)) {
728 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
729 inet_csk(sk)->icsk_af_ops->net_header_len -
730 inet_csk(sk)->icsk_ext_hdr_len -
731 tp->tcp_header_len);
732
733 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
734
735 /* We try hard to avoid divides here */
736 old_size_goal = tp->xmit_size_goal_segs * mss_now;
737
738 if (likely(old_size_goal <= xmit_size_goal &&
739 old_size_goal + mss_now > xmit_size_goal)) {
740 xmit_size_goal = old_size_goal;
741 } else {
742 tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
743 xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
744 }
745 }
746
747 return max(xmit_size_goal, mss_now);
748}
749
750static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
751{
752 int mss_now;
753
754 mss_now = tcp_current_mss(sk);
755 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
756
757 return mss_now;
758}
759
760static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
761 size_t psize, int flags)
762{
763 struct tcp_sock *tp = tcp_sk(sk);
764 int mss_now, size_goal;
765 int err;
766 ssize_t copied;
767 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
768
769 /* Wait for a connection to finish. */
770 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
771 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
772 goto out_err;
773
774 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
775
776 mss_now = tcp_send_mss(sk, &size_goal, flags);
777 copied = 0;
778
779 err = -EPIPE;
780 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
781 goto out_err;
782
783 while (psize > 0) {
784 struct sk_buff *skb = tcp_write_queue_tail(sk);
785 struct page *page = pages[poffset / PAGE_SIZE];
786 int copy, i, can_coalesce;
787 int offset = poffset % PAGE_SIZE;
788 int size = min_t(size_t, psize, PAGE_SIZE - offset);
789
790 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
791new_segment:
792 if (!sk_stream_memory_free(sk))
793 goto wait_for_sndbuf;
794
795 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
796 if (!skb)
797 goto wait_for_memory;
798
799 skb_entail(sk, skb);
800 copy = size_goal;
801 }
802
803 if (copy > size)
804 copy = size;
805
806 i = skb_shinfo(skb)->nr_frags;
807 can_coalesce = skb_can_coalesce(skb, i, page, offset);
808 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
809 tcp_mark_push(tp, skb);
810 goto new_segment;
811 }
812 if (!sk_wmem_schedule(sk, copy))
813 goto wait_for_memory;
814
815 if (can_coalesce) {
816 skb_shinfo(skb)->frags[i - 1].size += copy;
817 } else {
818 get_page(page);
819 skb_fill_page_desc(skb, i, page, offset, copy);
820 }
821
822 skb->len += copy;
823 skb->data_len += copy;
824 skb->truesize += copy;
825 sk->sk_wmem_queued += copy;
826 sk_mem_charge(sk, copy);
827 skb->ip_summed = CHECKSUM_PARTIAL;
828 tp->write_seq += copy;
829 TCP_SKB_CB(skb)->end_seq += copy;
830 skb_shinfo(skb)->gso_segs = 0;
831
832 if (!copied)
833 TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH;
834
835 copied += copy;
836 poffset += copy;
837 if (!(psize -= copy))
838 goto out;
839
840 if (skb->len < size_goal || (flags & MSG_OOB))
841 continue;
842
843 if (forced_push(tp)) {
844 tcp_mark_push(tp, skb);
845 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
846 } else if (skb == tcp_send_head(sk))
847 tcp_push_one(sk, mss_now);
848 continue;
849
850wait_for_sndbuf:
851 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
852wait_for_memory:
853 if (copied)
854 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
855
856 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
857 goto do_error;
858
859 mss_now = tcp_send_mss(sk, &size_goal, flags);
860 }
861
862out:
863 if (copied)
864 tcp_push(sk, flags, mss_now, tp->nonagle);
865 return copied;
866
867do_error:
868 if (copied)
869 goto out;
870out_err:
871 return sk_stream_error(sk, flags, err);
872}
873
874int tcp_sendpage(struct sock *sk, struct page *page, int offset,
875 size_t size, int flags)
876{
877 ssize_t res;
878
879 if (!(sk->sk_route_caps & NETIF_F_SG) ||
880 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
881 return sock_no_sendpage(sk->sk_socket, page, offset, size,
882 flags);
883
884 lock_sock(sk);
885 res = do_tcp_sendpages(sk, &page, offset, size, flags);
886 release_sock(sk);
887 return res;
888}
889EXPORT_SYMBOL(tcp_sendpage);
890
891#define TCP_PAGE(sk) (sk->sk_sndmsg_page)
892#define TCP_OFF(sk) (sk->sk_sndmsg_off)
893
894static inline int select_size(struct sock *sk, int sg)
895{
896 struct tcp_sock *tp = tcp_sk(sk);
897 int tmp = tp->mss_cache;
898
899 if (sg) {
900 if (sk_can_gso(sk))
901 tmp = 0;
902 else {
903 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
904
905 if (tmp >= pgbreak &&
906 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
907 tmp = pgbreak;
908 }
909 }
910
911 return tmp;
912}
913
914int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
915 size_t size)
916{
917 struct iovec *iov;
918 struct tcp_sock *tp = tcp_sk(sk);
919 struct sk_buff *skb;
920 int iovlen, flags;
921 int mss_now, size_goal;
922 int sg, err, copied;
923 long timeo;
924
925 lock_sock(sk);
926
927 flags = msg->msg_flags;
928 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
929
930 /* Wait for a connection to finish. */
931 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
932 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
933 goto out_err;
934
935 /* This should be in poll */
936 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
937
938 mss_now = tcp_send_mss(sk, &size_goal, flags);
939
940 /* Ok commence sending. */
941 iovlen = msg->msg_iovlen;
942 iov = msg->msg_iov;
943 copied = 0;
944
945 err = -EPIPE;
946 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
947 goto out_err;
948
949 sg = sk->sk_route_caps & NETIF_F_SG;
950
951 while (--iovlen >= 0) {
952 size_t seglen = iov->iov_len;
953 unsigned char __user *from = iov->iov_base;
954
955 iov++;
956
957 while (seglen > 0) {
958 int copy = 0;
959 int max = size_goal;
960
961 skb = tcp_write_queue_tail(sk);
962 if (tcp_send_head(sk)) {
963 if (skb->ip_summed == CHECKSUM_NONE)
964 max = mss_now;
965 copy = max - skb->len;
966 }
967
968 if (copy <= 0) {
969new_segment:
970 /* Allocate new segment. If the interface is SG,
971 * allocate skb fitting to single page.
972 */
973 if (!sk_stream_memory_free(sk))
974 goto wait_for_sndbuf;
975
976 skb = sk_stream_alloc_skb(sk,
977 select_size(sk, sg),
978 sk->sk_allocation);
979 if (!skb)
980 goto wait_for_memory;
981
982 /*
983 * Check whether we can use HW checksum.
984 */
985 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
986 skb->ip_summed = CHECKSUM_PARTIAL;
987
988 skb_entail(sk, skb);
989 copy = size_goal;
990 max = size_goal;
991 }
992
993 /* Try to append data to the end of skb. */
994 if (copy > seglen)
995 copy = seglen;
996
997 /* Where to copy to? */
998 if (skb_tailroom(skb) > 0) {
999 /* We have some space in skb head. Superb! */
1000 if (copy > skb_tailroom(skb))
1001 copy = skb_tailroom(skb);
1002 err = skb_add_data_nocache(sk, skb, from, copy);
1003 if (err)
1004 goto do_fault;
1005 } else {
1006 int merge = 0;
1007 int i = skb_shinfo(skb)->nr_frags;
1008 struct page *page = TCP_PAGE(sk);
1009 int off = TCP_OFF(sk);
1010
1011 if (skb_can_coalesce(skb, i, page, off) &&
1012 off != PAGE_SIZE) {
1013 /* We can extend the last page
1014 * fragment. */
1015 merge = 1;
1016 } else if (i == MAX_SKB_FRAGS || !sg) {
1017 /* Need to add new fragment and cannot
1018 * do this because interface is non-SG,
1019 * or because all the page slots are
1020 * busy. */
1021 tcp_mark_push(tp, skb);
1022 goto new_segment;
1023 } else if (page) {
1024 if (off == PAGE_SIZE) {
1025 put_page(page);
1026 TCP_PAGE(sk) = page = NULL;
1027 off = 0;
1028 }
1029 } else
1030 off = 0;
1031
1032 if (copy > PAGE_SIZE - off)
1033 copy = PAGE_SIZE - off;
1034
1035 if (!sk_wmem_schedule(sk, copy))
1036 goto wait_for_memory;
1037
1038 if (!page) {
1039 /* Allocate new cache page. */
1040 if (!(page = sk_stream_alloc_page(sk)))
1041 goto wait_for_memory;
1042 }
1043
1044 /* Time to copy data. We are close to
1045 * the end! */
1046 err = skb_copy_to_page_nocache(sk, from, skb,
1047 page, off, copy);
1048 if (err) {
1049 /* If this page was new, give it to the
1050 * socket so it does not get leaked.
1051 */
1052 if (!TCP_PAGE(sk)) {
1053 TCP_PAGE(sk) = page;
1054 TCP_OFF(sk) = 0;
1055 }
1056 goto do_error;
1057 }
1058
1059 /* Update the skb. */
1060 if (merge) {
1061 skb_shinfo(skb)->frags[i - 1].size +=
1062 copy;
1063 } else {
1064 skb_fill_page_desc(skb, i, page, off, copy);
1065 if (TCP_PAGE(sk)) {
1066 get_page(page);
1067 } else if (off + copy < PAGE_SIZE) {
1068 get_page(page);
1069 TCP_PAGE(sk) = page;
1070 }
1071 }
1072
1073 TCP_OFF(sk) = off + copy;
1074 }
1075
1076 if (!copied)
1077 TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH;
1078
1079 tp->write_seq += copy;
1080 TCP_SKB_CB(skb)->end_seq += copy;
1081 skb_shinfo(skb)->gso_segs = 0;
1082
1083 from += copy;
1084 copied += copy;
1085 if ((seglen -= copy) == 0 && iovlen == 0)
1086 goto out;
1087
1088 if (skb->len < max || (flags & MSG_OOB))
1089 continue;
1090
1091 if (forced_push(tp)) {
1092 tcp_mark_push(tp, skb);
1093 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1094 } else if (skb == tcp_send_head(sk))
1095 tcp_push_one(sk, mss_now);
1096 continue;
1097
1098wait_for_sndbuf:
1099 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1100wait_for_memory:
1101 if (copied)
1102 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1103
1104 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1105 goto do_error;
1106
1107 mss_now = tcp_send_mss(sk, &size_goal, flags);
1108 }
1109 }
1110
1111out:
1112 if (copied)
1113 tcp_push(sk, flags, mss_now, tp->nonagle);
1114 release_sock(sk);
1115 return copied;
1116
1117do_fault:
1118 if (!skb->len) {
1119 tcp_unlink_write_queue(skb, sk);
1120 /* It is the one place in all of TCP, except connection
1121 * reset, where we can be unlinking the send_head.
1122 */
1123 tcp_check_send_head(sk, skb);
1124 sk_wmem_free_skb(sk, skb);
1125 }
1126
1127do_error:
1128 if (copied)
1129 goto out;
1130out_err:
1131 err = sk_stream_error(sk, flags, err);
1132 release_sock(sk);
1133 return err;
1134}
1135EXPORT_SYMBOL(tcp_sendmsg);
1136
1137/*
1138 * Handle reading urgent data. BSD has very simple semantics for
1139 * this, no blocking and very strange errors 8)
1140 */
1141
1142static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1143{
1144 struct tcp_sock *tp = tcp_sk(sk);
1145
1146 /* No URG data to read. */
1147 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1148 tp->urg_data == TCP_URG_READ)
1149 return -EINVAL; /* Yes this is right ! */
1150
1151 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1152 return -ENOTCONN;
1153
1154 if (tp->urg_data & TCP_URG_VALID) {
1155 int err = 0;
1156 char c = tp->urg_data;
1157
1158 if (!(flags & MSG_PEEK))
1159 tp->urg_data = TCP_URG_READ;
1160
1161 /* Read urgent data. */
1162 msg->msg_flags |= MSG_OOB;
1163
1164 if (len > 0) {
1165 if (!(flags & MSG_TRUNC))
1166 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1167 len = 1;
1168 } else
1169 msg->msg_flags |= MSG_TRUNC;
1170
1171 return err ? -EFAULT : len;
1172 }
1173
1174 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1175 return 0;
1176
1177 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1178 * the available implementations agree in this case:
1179 * this call should never block, independent of the
1180 * blocking state of the socket.
1181 * Mike <pall@rz.uni-karlsruhe.de>
1182 */
1183 return -EAGAIN;
1184}
1185
1186/* Clean up the receive buffer for full frames taken by the user,
1187 * then send an ACK if necessary. COPIED is the number of bytes
1188 * tcp_recvmsg has given to the user so far, it speeds up the
1189 * calculation of whether or not we must ACK for the sake of
1190 * a window update.
1191 */
1192void tcp_cleanup_rbuf(struct sock *sk, int copied)
1193{
1194 struct tcp_sock *tp = tcp_sk(sk);
1195 int time_to_ack = 0;
1196
1197#if TCP_DEBUG
1198 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1199
1200 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1201 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1202 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1203#endif
1204
1205 if (inet_csk_ack_scheduled(sk)) {
1206 const struct inet_connection_sock *icsk = inet_csk(sk);
1207 /* Delayed ACKs frequently hit locked sockets during bulk
1208 * receive. */
1209 if (icsk->icsk_ack.blocked ||
1210 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1211 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1212 /*
1213 * If this read emptied read buffer, we send ACK, if
1214 * connection is not bidirectional, user drained
1215 * receive buffer and there was a small segment
1216 * in queue.
1217 */
1218 (copied > 0 &&
1219 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1220 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1221 !icsk->icsk_ack.pingpong)) &&
1222 !atomic_read(&sk->sk_rmem_alloc)))
1223 time_to_ack = 1;
1224 }
1225
1226 /* We send an ACK if we can now advertise a non-zero window
1227 * which has been raised "significantly".
1228 *
1229 * Even if window raised up to infinity, do not send window open ACK
1230 * in states, where we will not receive more. It is useless.
1231 */
1232 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1233 __u32 rcv_window_now = tcp_receive_window(tp);
1234
1235 /* Optimize, __tcp_select_window() is not cheap. */
1236 if (2*rcv_window_now <= tp->window_clamp) {
1237 __u32 new_window = __tcp_select_window(sk);
1238
1239 /* Send ACK now, if this read freed lots of space
1240 * in our buffer. Certainly, new_window is new window.
1241 * We can advertise it now, if it is not less than current one.
1242 * "Lots" means "at least twice" here.
1243 */
1244 if (new_window && new_window >= 2 * rcv_window_now)
1245 time_to_ack = 1;
1246 }
1247 }
1248 if (time_to_ack)
1249 tcp_send_ack(sk);
1250}
1251
1252static void tcp_prequeue_process(struct sock *sk)
1253{
1254 struct sk_buff *skb;
1255 struct tcp_sock *tp = tcp_sk(sk);
1256
1257 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1258
1259 /* RX process wants to run with disabled BHs, though it is not
1260 * necessary */
1261 local_bh_disable();
1262 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1263 sk_backlog_rcv(sk, skb);
1264 local_bh_enable();
1265
1266 /* Clear memory counter. */
1267 tp->ucopy.memory = 0;
1268}
1269
1270#ifdef CONFIG_NET_DMA
1271static void tcp_service_net_dma(struct sock *sk, bool wait)
1272{
1273 dma_cookie_t done, used;
1274 dma_cookie_t last_issued;
1275 struct tcp_sock *tp = tcp_sk(sk);
1276
1277 if (!tp->ucopy.dma_chan)
1278 return;
1279
1280 last_issued = tp->ucopy.dma_cookie;
1281 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1282
1283 do {
1284 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1285 last_issued, &done,
1286 &used) == DMA_SUCCESS) {
1287 /* Safe to free early-copied skbs now */
1288 __skb_queue_purge(&sk->sk_async_wait_queue);
1289 break;
1290 } else {
1291 struct sk_buff *skb;
1292 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1293 (dma_async_is_complete(skb->dma_cookie, done,
1294 used) == DMA_SUCCESS)) {
1295 __skb_dequeue(&sk->sk_async_wait_queue);
1296 kfree_skb(skb);
1297 }
1298 }
1299 } while (wait);
1300}
1301#endif
1302
1303static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1304{
1305 struct sk_buff *skb;
1306 u32 offset;
1307
1308 skb_queue_walk(&sk->sk_receive_queue, skb) {
1309 offset = seq - TCP_SKB_CB(skb)->seq;
1310 if (tcp_hdr(skb)->syn)
1311 offset--;
1312 if (offset < skb->len || tcp_hdr(skb)->fin) {
1313 *off = offset;
1314 return skb;
1315 }
1316 }
1317 return NULL;
1318}
1319
1320/*
1321 * This routine provides an alternative to tcp_recvmsg() for routines
1322 * that would like to handle copying from skbuffs directly in 'sendfile'
1323 * fashion.
1324 * Note:
1325 * - It is assumed that the socket was locked by the caller.
1326 * - The routine does not block.
1327 * - At present, there is no support for reading OOB data
1328 * or for 'peeking' the socket using this routine
1329 * (although both would be easy to implement).
1330 */
1331int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1332 sk_read_actor_t recv_actor)
1333{
1334 struct sk_buff *skb;
1335 struct tcp_sock *tp = tcp_sk(sk);
1336 u32 seq = tp->copied_seq;
1337 u32 offset;
1338 int copied = 0;
1339
1340 if (sk->sk_state == TCP_LISTEN)
1341 return -ENOTCONN;
1342 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1343 if (offset < skb->len) {
1344 int used;
1345 size_t len;
1346
1347 len = skb->len - offset;
1348 /* Stop reading if we hit a patch of urgent data */
1349 if (tp->urg_data) {
1350 u32 urg_offset = tp->urg_seq - seq;
1351 if (urg_offset < len)
1352 len = urg_offset;
1353 if (!len)
1354 break;
1355 }
1356 used = recv_actor(desc, skb, offset, len);
1357 if (used < 0) {
1358 if (!copied)
1359 copied = used;
1360 break;
1361 } else if (used <= len) {
1362 seq += used;
1363 copied += used;
1364 offset += used;
1365 }
1366 /*
1367 * If recv_actor drops the lock (e.g. TCP splice
1368 * receive) the skb pointer might be invalid when
1369 * getting here: tcp_collapse might have deleted it
1370 * while aggregating skbs from the socket queue.
1371 */
1372 skb = tcp_recv_skb(sk, seq-1, &offset);
1373 if (!skb || (offset+1 != skb->len))
1374 break;
1375 }
1376 if (tcp_hdr(skb)->fin) {
1377 sk_eat_skb(sk, skb, 0);
1378 ++seq;
1379 break;
1380 }
1381 sk_eat_skb(sk, skb, 0);
1382 if (!desc->count)
1383 break;
1384 tp->copied_seq = seq;
1385 }
1386 tp->copied_seq = seq;
1387
1388 tcp_rcv_space_adjust(sk);
1389
1390 /* Clean up data we have read: This will do ACK frames. */
1391 if (copied > 0)
1392 tcp_cleanup_rbuf(sk, copied);
1393 return copied;
1394}
1395EXPORT_SYMBOL(tcp_read_sock);
1396
1397/*
1398 * This routine copies from a sock struct into the user buffer.
1399 *
1400 * Technical note: in 2.3 we work on _locked_ socket, so that
1401 * tricks with *seq access order and skb->users are not required.
1402 * Probably, code can be easily improved even more.
1403 */
1404
1405int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1406 size_t len, int nonblock, int flags, int *addr_len)
1407{
1408 struct tcp_sock *tp = tcp_sk(sk);
1409 int copied = 0;
1410 u32 peek_seq;
1411 u32 *seq;
1412 unsigned long used;
1413 int err;
1414 int target; /* Read at least this many bytes */
1415 long timeo;
1416 struct task_struct *user_recv = NULL;
1417 int copied_early = 0;
1418 struct sk_buff *skb;
1419 u32 urg_hole = 0;
1420
1421 lock_sock(sk);
1422
1423 err = -ENOTCONN;
1424 if (sk->sk_state == TCP_LISTEN)
1425 goto out;
1426
1427 timeo = sock_rcvtimeo(sk, nonblock);
1428
1429 /* Urgent data needs to be handled specially. */
1430 if (flags & MSG_OOB)
1431 goto recv_urg;
1432
1433 seq = &tp->copied_seq;
1434 if (flags & MSG_PEEK) {
1435 peek_seq = tp->copied_seq;
1436 seq = &peek_seq;
1437 }
1438
1439 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1440
1441#ifdef CONFIG_NET_DMA
1442 tp->ucopy.dma_chan = NULL;
1443 preempt_disable();
1444 skb = skb_peek_tail(&sk->sk_receive_queue);
1445 {
1446 int available = 0;
1447
1448 if (skb)
1449 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1450 if ((available < target) &&
1451 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1452 !sysctl_tcp_low_latency &&
1453 dma_find_channel(DMA_MEMCPY)) {
1454 preempt_enable_no_resched();
1455 tp->ucopy.pinned_list =
1456 dma_pin_iovec_pages(msg->msg_iov, len);
1457 } else {
1458 preempt_enable_no_resched();
1459 }
1460 }
1461#endif
1462
1463 do {
1464 u32 offset;
1465
1466 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1467 if (tp->urg_data && tp->urg_seq == *seq) {
1468 if (copied)
1469 break;
1470 if (signal_pending(current)) {
1471 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1472 break;
1473 }
1474 }
1475
1476 /* Next get a buffer. */
1477
1478 skb_queue_walk(&sk->sk_receive_queue, skb) {
1479 /* Now that we have two receive queues this
1480 * shouldn't happen.
1481 */
1482 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1483 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1484 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1485 flags))
1486 break;
1487
1488 offset = *seq - TCP_SKB_CB(skb)->seq;
1489 if (tcp_hdr(skb)->syn)
1490 offset--;
1491 if (offset < skb->len)
1492 goto found_ok_skb;
1493 if (tcp_hdr(skb)->fin)
1494 goto found_fin_ok;
1495 WARN(!(flags & MSG_PEEK),
1496 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1497 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1498 }
1499
1500 /* Well, if we have backlog, try to process it now yet. */
1501
1502 if (copied >= target && !sk->sk_backlog.tail)
1503 break;
1504
1505 if (copied) {
1506 if (sk->sk_err ||
1507 sk->sk_state == TCP_CLOSE ||
1508 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1509 !timeo ||
1510 signal_pending(current))
1511 break;
1512 } else {
1513 if (sock_flag(sk, SOCK_DONE))
1514 break;
1515
1516 if (sk->sk_err) {
1517 copied = sock_error(sk);
1518 break;
1519 }
1520
1521 if (sk->sk_shutdown & RCV_SHUTDOWN)
1522 break;
1523
1524 if (sk->sk_state == TCP_CLOSE) {
1525 if (!sock_flag(sk, SOCK_DONE)) {
1526 /* This occurs when user tries to read
1527 * from never connected socket.
1528 */
1529 copied = -ENOTCONN;
1530 break;
1531 }
1532 break;
1533 }
1534
1535 if (!timeo) {
1536 copied = -EAGAIN;
1537 break;
1538 }
1539
1540 if (signal_pending(current)) {
1541 copied = sock_intr_errno(timeo);
1542 break;
1543 }
1544 }
1545
1546 tcp_cleanup_rbuf(sk, copied);
1547
1548 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1549 /* Install new reader */
1550 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1551 user_recv = current;
1552 tp->ucopy.task = user_recv;
1553 tp->ucopy.iov = msg->msg_iov;
1554 }
1555
1556 tp->ucopy.len = len;
1557
1558 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1559 !(flags & (MSG_PEEK | MSG_TRUNC)));
1560
1561 /* Ugly... If prequeue is not empty, we have to
1562 * process it before releasing socket, otherwise
1563 * order will be broken at second iteration.
1564 * More elegant solution is required!!!
1565 *
1566 * Look: we have the following (pseudo)queues:
1567 *
1568 * 1. packets in flight
1569 * 2. backlog
1570 * 3. prequeue
1571 * 4. receive_queue
1572 *
1573 * Each queue can be processed only if the next ones
1574 * are empty. At this point we have empty receive_queue.
1575 * But prequeue _can_ be not empty after 2nd iteration,
1576 * when we jumped to start of loop because backlog
1577 * processing added something to receive_queue.
1578 * We cannot release_sock(), because backlog contains
1579 * packets arrived _after_ prequeued ones.
1580 *
1581 * Shortly, algorithm is clear --- to process all
1582 * the queues in order. We could make it more directly,
1583 * requeueing packets from backlog to prequeue, if
1584 * is not empty. It is more elegant, but eats cycles,
1585 * unfortunately.
1586 */
1587 if (!skb_queue_empty(&tp->ucopy.prequeue))
1588 goto do_prequeue;
1589
1590 /* __ Set realtime policy in scheduler __ */
1591 }
1592
1593#ifdef CONFIG_NET_DMA
1594 if (tp->ucopy.dma_chan)
1595 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1596#endif
1597 if (copied >= target) {
1598 /* Do not sleep, just process backlog. */
1599 release_sock(sk);
1600 lock_sock(sk);
1601 } else
1602 sk_wait_data(sk, &timeo);
1603
1604#ifdef CONFIG_NET_DMA
1605 tcp_service_net_dma(sk, false); /* Don't block */
1606 tp->ucopy.wakeup = 0;
1607#endif
1608
1609 if (user_recv) {
1610 int chunk;
1611
1612 /* __ Restore normal policy in scheduler __ */
1613
1614 if ((chunk = len - tp->ucopy.len) != 0) {
1615 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1616 len -= chunk;
1617 copied += chunk;
1618 }
1619
1620 if (tp->rcv_nxt == tp->copied_seq &&
1621 !skb_queue_empty(&tp->ucopy.prequeue)) {
1622do_prequeue:
1623 tcp_prequeue_process(sk);
1624
1625 if ((chunk = len - tp->ucopy.len) != 0) {
1626 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1627 len -= chunk;
1628 copied += chunk;
1629 }
1630 }
1631 }
1632 if ((flags & MSG_PEEK) &&
1633 (peek_seq - copied - urg_hole != tp->copied_seq)) {
1634 if (net_ratelimit())
1635 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1636 current->comm, task_pid_nr(current));
1637 peek_seq = tp->copied_seq;
1638 }
1639 continue;
1640
1641 found_ok_skb:
1642 /* Ok so how much can we use? */
1643 used = skb->len - offset;
1644 if (len < used)
1645 used = len;
1646
1647 /* Do we have urgent data here? */
1648 if (tp->urg_data) {
1649 u32 urg_offset = tp->urg_seq - *seq;
1650 if (urg_offset < used) {
1651 if (!urg_offset) {
1652 if (!sock_flag(sk, SOCK_URGINLINE)) {
1653 ++*seq;
1654 urg_hole++;
1655 offset++;
1656 used--;
1657 if (!used)
1658 goto skip_copy;
1659 }
1660 } else
1661 used = urg_offset;
1662 }
1663 }
1664
1665 if (!(flags & MSG_TRUNC)) {
1666#ifdef CONFIG_NET_DMA
1667 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1668 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1669
1670 if (tp->ucopy.dma_chan) {
1671 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1672 tp->ucopy.dma_chan, skb, offset,
1673 msg->msg_iov, used,
1674 tp->ucopy.pinned_list);
1675
1676 if (tp->ucopy.dma_cookie < 0) {
1677
1678 printk(KERN_ALERT "dma_cookie < 0\n");
1679
1680 /* Exception. Bailout! */
1681 if (!copied)
1682 copied = -EFAULT;
1683 break;
1684 }
1685
1686 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1687
1688 if ((offset + used) == skb->len)
1689 copied_early = 1;
1690
1691 } else
1692#endif
1693 {
1694 err = skb_copy_datagram_iovec(skb, offset,
1695 msg->msg_iov, used);
1696 if (err) {
1697 /* Exception. Bailout! */
1698 if (!copied)
1699 copied = -EFAULT;
1700 break;
1701 }
1702 }
1703 }
1704
1705 *seq += used;
1706 copied += used;
1707 len -= used;
1708
1709 tcp_rcv_space_adjust(sk);
1710
1711skip_copy:
1712 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1713 tp->urg_data = 0;
1714 tcp_fast_path_check(sk);
1715 }
1716 if (used + offset < skb->len)
1717 continue;
1718
1719 if (tcp_hdr(skb)->fin)
1720 goto found_fin_ok;
1721 if (!(flags & MSG_PEEK)) {
1722 sk_eat_skb(sk, skb, copied_early);
1723 copied_early = 0;
1724 }
1725 continue;
1726
1727 found_fin_ok:
1728 /* Process the FIN. */
1729 ++*seq;
1730 if (!(flags & MSG_PEEK)) {
1731 sk_eat_skb(sk, skb, copied_early);
1732 copied_early = 0;
1733 }
1734 break;
1735 } while (len > 0);
1736
1737 if (user_recv) {
1738 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1739 int chunk;
1740
1741 tp->ucopy.len = copied > 0 ? len : 0;
1742
1743 tcp_prequeue_process(sk);
1744
1745 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1746 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1747 len -= chunk;
1748 copied += chunk;
1749 }
1750 }
1751
1752 tp->ucopy.task = NULL;
1753 tp->ucopy.len = 0;
1754 }
1755
1756#ifdef CONFIG_NET_DMA
1757 tcp_service_net_dma(sk, true); /* Wait for queue to drain */
1758 tp->ucopy.dma_chan = NULL;
1759
1760 if (tp->ucopy.pinned_list) {
1761 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1762 tp->ucopy.pinned_list = NULL;
1763 }
1764#endif
1765
1766 /* According to UNIX98, msg_name/msg_namelen are ignored
1767 * on connected socket. I was just happy when found this 8) --ANK
1768 */
1769
1770 /* Clean up data we have read: This will do ACK frames. */
1771 tcp_cleanup_rbuf(sk, copied);
1772
1773 release_sock(sk);
1774 return copied;
1775
1776out:
1777 release_sock(sk);
1778 return err;
1779
1780recv_urg:
1781 err = tcp_recv_urg(sk, msg, len, flags);
1782 goto out;
1783}
1784EXPORT_SYMBOL(tcp_recvmsg);
1785
1786void tcp_set_state(struct sock *sk, int state)
1787{
1788 int oldstate = sk->sk_state;
1789
1790 switch (state) {
1791 case TCP_ESTABLISHED:
1792 if (oldstate != TCP_ESTABLISHED)
1793 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1794 break;
1795
1796 case TCP_CLOSE:
1797 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1798 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1799
1800 sk->sk_prot->unhash(sk);
1801 if (inet_csk(sk)->icsk_bind_hash &&
1802 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1803 inet_put_port(sk);
1804 /* fall through */
1805 default:
1806 if (oldstate == TCP_ESTABLISHED)
1807 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1808 }
1809
1810 /* Change state AFTER socket is unhashed to avoid closed
1811 * socket sitting in hash tables.
1812 */
1813 sk->sk_state = state;
1814
1815#ifdef STATE_TRACE
1816 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1817#endif
1818}
1819EXPORT_SYMBOL_GPL(tcp_set_state);
1820
1821/*
1822 * State processing on a close. This implements the state shift for
1823 * sending our FIN frame. Note that we only send a FIN for some
1824 * states. A shutdown() may have already sent the FIN, or we may be
1825 * closed.
1826 */
1827
1828static const unsigned char new_state[16] = {
1829 /* current state: new state: action: */
1830 /* (Invalid) */ TCP_CLOSE,
1831 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1832 /* TCP_SYN_SENT */ TCP_CLOSE,
1833 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1834 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1835 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1836 /* TCP_TIME_WAIT */ TCP_CLOSE,
1837 /* TCP_CLOSE */ TCP_CLOSE,
1838 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1839 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1840 /* TCP_LISTEN */ TCP_CLOSE,
1841 /* TCP_CLOSING */ TCP_CLOSING,
1842};
1843
1844static int tcp_close_state(struct sock *sk)
1845{
1846 int next = (int)new_state[sk->sk_state];
1847 int ns = next & TCP_STATE_MASK;
1848
1849 tcp_set_state(sk, ns);
1850
1851 return next & TCP_ACTION_FIN;
1852}
1853
1854/*
1855 * Shutdown the sending side of a connection. Much like close except
1856 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1857 */
1858
1859void tcp_shutdown(struct sock *sk, int how)
1860{
1861 /* We need to grab some memory, and put together a FIN,
1862 * and then put it into the queue to be sent.
1863 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1864 */
1865 if (!(how & SEND_SHUTDOWN))
1866 return;
1867
1868 /* If we've already sent a FIN, or it's a closed state, skip this. */
1869 if ((1 << sk->sk_state) &
1870 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1871 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1872 /* Clear out any half completed packets. FIN if needed. */
1873 if (tcp_close_state(sk))
1874 tcp_send_fin(sk);
1875 }
1876}
1877EXPORT_SYMBOL(tcp_shutdown);
1878
1879void tcp_close(struct sock *sk, long timeout)
1880{
1881 struct sk_buff *skb;
1882 int data_was_unread = 0;
1883 int state;
1884
1885 lock_sock(sk);
1886 sk->sk_shutdown = SHUTDOWN_MASK;
1887
1888 if (sk->sk_state == TCP_LISTEN) {
1889 tcp_set_state(sk, TCP_CLOSE);
1890
1891 /* Special case. */
1892 inet_csk_listen_stop(sk);
1893
1894 goto adjudge_to_death;
1895 }
1896
1897 /* We need to flush the recv. buffs. We do this only on the
1898 * descriptor close, not protocol-sourced closes, because the
1899 * reader process may not have drained the data yet!
1900 */
1901 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1902 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1903 tcp_hdr(skb)->fin;
1904 data_was_unread += len;
1905 __kfree_skb(skb);
1906 }
1907
1908 sk_mem_reclaim(sk);
1909
1910 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
1911 if (sk->sk_state == TCP_CLOSE)
1912 goto adjudge_to_death;
1913
1914 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1915 * data was lost. To witness the awful effects of the old behavior of
1916 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1917 * GET in an FTP client, suspend the process, wait for the client to
1918 * advertise a zero window, then kill -9 the FTP client, wheee...
1919 * Note: timeout is always zero in such a case.
1920 */
1921 if (data_was_unread) {
1922 /* Unread data was tossed, zap the connection. */
1923 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1924 tcp_set_state(sk, TCP_CLOSE);
1925 tcp_send_active_reset(sk, sk->sk_allocation);
1926 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1927 /* Check zero linger _after_ checking for unread data. */
1928 sk->sk_prot->disconnect(sk, 0);
1929 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1930 } else if (tcp_close_state(sk)) {
1931 /* We FIN if the application ate all the data before
1932 * zapping the connection.
1933 */
1934
1935 /* RED-PEN. Formally speaking, we have broken TCP state
1936 * machine. State transitions:
1937 *
1938 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1939 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1940 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1941 *
1942 * are legal only when FIN has been sent (i.e. in window),
1943 * rather than queued out of window. Purists blame.
1944 *
1945 * F.e. "RFC state" is ESTABLISHED,
1946 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1947 *
1948 * The visible declinations are that sometimes
1949 * we enter time-wait state, when it is not required really
1950 * (harmless), do not send active resets, when they are
1951 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1952 * they look as CLOSING or LAST_ACK for Linux)
1953 * Probably, I missed some more holelets.
1954 * --ANK
1955 */
1956 tcp_send_fin(sk);
1957 }
1958
1959 sk_stream_wait_close(sk, timeout);
1960
1961adjudge_to_death:
1962 state = sk->sk_state;
1963 sock_hold(sk);
1964 sock_orphan(sk);
1965
1966 /* It is the last release_sock in its life. It will remove backlog. */
1967 release_sock(sk);
1968
1969
1970 /* Now socket is owned by kernel and we acquire BH lock
1971 to finish close. No need to check for user refs.
1972 */
1973 local_bh_disable();
1974 bh_lock_sock(sk);
1975 WARN_ON(sock_owned_by_user(sk));
1976
1977 percpu_counter_inc(sk->sk_prot->orphan_count);
1978
1979 /* Have we already been destroyed by a softirq or backlog? */
1980 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1981 goto out;
1982
1983 /* This is a (useful) BSD violating of the RFC. There is a
1984 * problem with TCP as specified in that the other end could
1985 * keep a socket open forever with no application left this end.
1986 * We use a 3 minute timeout (about the same as BSD) then kill
1987 * our end. If they send after that then tough - BUT: long enough
1988 * that we won't make the old 4*rto = almost no time - whoops
1989 * reset mistake.
1990 *
1991 * Nope, it was not mistake. It is really desired behaviour
1992 * f.e. on http servers, when such sockets are useless, but
1993 * consume significant resources. Let's do it with special
1994 * linger2 option. --ANK
1995 */
1996
1997 if (sk->sk_state == TCP_FIN_WAIT2) {
1998 struct tcp_sock *tp = tcp_sk(sk);
1999 if (tp->linger2 < 0) {
2000 tcp_set_state(sk, TCP_CLOSE);
2001 tcp_send_active_reset(sk, GFP_ATOMIC);
2002 NET_INC_STATS_BH(sock_net(sk),
2003 LINUX_MIB_TCPABORTONLINGER);
2004 } else {
2005 const int tmo = tcp_fin_time(sk);
2006
2007 if (tmo > TCP_TIMEWAIT_LEN) {
2008 inet_csk_reset_keepalive_timer(sk,
2009 tmo - TCP_TIMEWAIT_LEN);
2010 } else {
2011 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2012 goto out;
2013 }
2014 }
2015 }
2016 if (sk->sk_state != TCP_CLOSE) {
2017 sk_mem_reclaim(sk);
2018 if (tcp_too_many_orphans(sk, 0)) {
2019 if (net_ratelimit())
2020 printk(KERN_INFO "TCP: too many of orphaned "
2021 "sockets\n");
2022 tcp_set_state(sk, TCP_CLOSE);
2023 tcp_send_active_reset(sk, GFP_ATOMIC);
2024 NET_INC_STATS_BH(sock_net(sk),
2025 LINUX_MIB_TCPABORTONMEMORY);
2026 }
2027 }
2028
2029 if (sk->sk_state == TCP_CLOSE)
2030 inet_csk_destroy_sock(sk);
2031 /* Otherwise, socket is reprieved until protocol close. */
2032
2033out:
2034 bh_unlock_sock(sk);
2035 local_bh_enable();
2036 sock_put(sk);
2037}
2038EXPORT_SYMBOL(tcp_close);
2039
2040/* These states need RST on ABORT according to RFC793 */
2041
2042static inline int tcp_need_reset(int state)
2043{
2044 return (1 << state) &
2045 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2046 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2047}
2048
2049int tcp_disconnect(struct sock *sk, int flags)
2050{
2051 struct inet_sock *inet = inet_sk(sk);
2052 struct inet_connection_sock *icsk = inet_csk(sk);
2053 struct tcp_sock *tp = tcp_sk(sk);
2054 int err = 0;
2055 int old_state = sk->sk_state;
2056
2057 if (old_state != TCP_CLOSE)
2058 tcp_set_state(sk, TCP_CLOSE);
2059
2060 /* ABORT function of RFC793 */
2061 if (old_state == TCP_LISTEN) {
2062 inet_csk_listen_stop(sk);
2063 } else if (tcp_need_reset(old_state) ||
2064 (tp->snd_nxt != tp->write_seq &&
2065 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2066 /* The last check adjusts for discrepancy of Linux wrt. RFC
2067 * states
2068 */
2069 tcp_send_active_reset(sk, gfp_any());
2070 sk->sk_err = ECONNRESET;
2071 } else if (old_state == TCP_SYN_SENT)
2072 sk->sk_err = ECONNRESET;
2073
2074 tcp_clear_xmit_timers(sk);
2075 __skb_queue_purge(&sk->sk_receive_queue);
2076 tcp_write_queue_purge(sk);
2077 __skb_queue_purge(&tp->out_of_order_queue);
2078#ifdef CONFIG_NET_DMA
2079 __skb_queue_purge(&sk->sk_async_wait_queue);
2080#endif
2081
2082 inet->inet_dport = 0;
2083
2084 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2085 inet_reset_saddr(sk);
2086
2087 sk->sk_shutdown = 0;
2088 sock_reset_flag(sk, SOCK_DONE);
2089 tp->srtt = 0;
2090 if ((tp->write_seq += tp->max_window + 2) == 0)
2091 tp->write_seq = 1;
2092 icsk->icsk_backoff = 0;
2093 tp->snd_cwnd = 2;
2094 icsk->icsk_probes_out = 0;
2095 tp->packets_out = 0;
2096 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2097 tp->snd_cwnd_cnt = 0;
2098 tp->bytes_acked = 0;
2099 tp->window_clamp = 0;
2100 tcp_set_ca_state(sk, TCP_CA_Open);
2101 tcp_clear_retrans(tp);
2102 inet_csk_delack_init(sk);
2103 tcp_init_send_head(sk);
2104 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2105 __sk_dst_reset(sk);
2106
2107 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2108
2109 sk->sk_error_report(sk);
2110 return err;
2111}
2112EXPORT_SYMBOL(tcp_disconnect);
2113
2114/*
2115 * Socket option code for TCP.
2116 */
2117static int do_tcp_setsockopt(struct sock *sk, int level,
2118 int optname, char __user *optval, unsigned int optlen)
2119{
2120 struct tcp_sock *tp = tcp_sk(sk);
2121 struct inet_connection_sock *icsk = inet_csk(sk);
2122 int val;
2123 int err = 0;
2124
2125 /* These are data/string values, all the others are ints */
2126 switch (optname) {
2127 case TCP_CONGESTION: {
2128 char name[TCP_CA_NAME_MAX];
2129
2130 if (optlen < 1)
2131 return -EINVAL;
2132
2133 val = strncpy_from_user(name, optval,
2134 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2135 if (val < 0)
2136 return -EFAULT;
2137 name[val] = 0;
2138
2139 lock_sock(sk);
2140 err = tcp_set_congestion_control(sk, name);
2141 release_sock(sk);
2142 return err;
2143 }
2144 case TCP_COOKIE_TRANSACTIONS: {
2145 struct tcp_cookie_transactions ctd;
2146 struct tcp_cookie_values *cvp = NULL;
2147
2148 if (sizeof(ctd) > optlen)
2149 return -EINVAL;
2150 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2151 return -EFAULT;
2152
2153 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2154 ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2155 return -EINVAL;
2156
2157 if (ctd.tcpct_cookie_desired == 0) {
2158 /* default to global value */
2159 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2160 ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2161 ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2162 return -EINVAL;
2163 }
2164
2165 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2166 /* Supercedes all other values */
2167 lock_sock(sk);
2168 if (tp->cookie_values != NULL) {
2169 kref_put(&tp->cookie_values->kref,
2170 tcp_cookie_values_release);
2171 tp->cookie_values = NULL;
2172 }
2173 tp->rx_opt.cookie_in_always = 0; /* false */
2174 tp->rx_opt.cookie_out_never = 1; /* true */
2175 release_sock(sk);
2176 return err;
2177 }
2178
2179 /* Allocate ancillary memory before locking.
2180 */
2181 if (ctd.tcpct_used > 0 ||
2182 (tp->cookie_values == NULL &&
2183 (sysctl_tcp_cookie_size > 0 ||
2184 ctd.tcpct_cookie_desired > 0 ||
2185 ctd.tcpct_s_data_desired > 0))) {
2186 cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2187 GFP_KERNEL);
2188 if (cvp == NULL)
2189 return -ENOMEM;
2190
2191 kref_init(&cvp->kref);
2192 }
2193 lock_sock(sk);
2194 tp->rx_opt.cookie_in_always =
2195 (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2196 tp->rx_opt.cookie_out_never = 0; /* false */
2197
2198 if (tp->cookie_values != NULL) {
2199 if (cvp != NULL) {
2200 /* Changed values are recorded by a changed
2201 * pointer, ensuring the cookie will differ,
2202 * without separately hashing each value later.
2203 */
2204 kref_put(&tp->cookie_values->kref,
2205 tcp_cookie_values_release);
2206 } else {
2207 cvp = tp->cookie_values;
2208 }
2209 }
2210
2211 if (cvp != NULL) {
2212 cvp->cookie_desired = ctd.tcpct_cookie_desired;
2213
2214 if (ctd.tcpct_used > 0) {
2215 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2216 ctd.tcpct_used);
2217 cvp->s_data_desired = ctd.tcpct_used;
2218 cvp->s_data_constant = 1; /* true */
2219 } else {
2220 /* No constant payload data. */
2221 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2222 cvp->s_data_constant = 0; /* false */
2223 }
2224
2225 tp->cookie_values = cvp;
2226 }
2227 release_sock(sk);
2228 return err;
2229 }
2230 default:
2231 /* fallthru */
2232 break;
2233 }
2234
2235 if (optlen < sizeof(int))
2236 return -EINVAL;
2237
2238 if (get_user(val, (int __user *)optval))
2239 return -EFAULT;
2240
2241 lock_sock(sk);
2242
2243 switch (optname) {
2244 case TCP_MAXSEG:
2245 /* Values greater than interface MTU won't take effect. However
2246 * at the point when this call is done we typically don't yet
2247 * know which interface is going to be used */
2248 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2249 err = -EINVAL;
2250 break;
2251 }
2252 tp->rx_opt.user_mss = val;
2253 break;
2254
2255 case TCP_NODELAY:
2256 if (val) {
2257 /* TCP_NODELAY is weaker than TCP_CORK, so that
2258 * this option on corked socket is remembered, but
2259 * it is not activated until cork is cleared.
2260 *
2261 * However, when TCP_NODELAY is set we make
2262 * an explicit push, which overrides even TCP_CORK
2263 * for currently queued segments.
2264 */
2265 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2266 tcp_push_pending_frames(sk);
2267 } else {
2268 tp->nonagle &= ~TCP_NAGLE_OFF;
2269 }
2270 break;
2271
2272 case TCP_THIN_LINEAR_TIMEOUTS:
2273 if (val < 0 || val > 1)
2274 err = -EINVAL;
2275 else
2276 tp->thin_lto = val;
2277 break;
2278
2279 case TCP_THIN_DUPACK:
2280 if (val < 0 || val > 1)
2281 err = -EINVAL;
2282 else
2283 tp->thin_dupack = val;
2284 break;
2285
2286 case TCP_CORK:
2287 /* When set indicates to always queue non-full frames.
2288 * Later the user clears this option and we transmit
2289 * any pending partial frames in the queue. This is
2290 * meant to be used alongside sendfile() to get properly
2291 * filled frames when the user (for example) must write
2292 * out headers with a write() call first and then use
2293 * sendfile to send out the data parts.
2294 *
2295 * TCP_CORK can be set together with TCP_NODELAY and it is
2296 * stronger than TCP_NODELAY.
2297 */
2298 if (val) {
2299 tp->nonagle |= TCP_NAGLE_CORK;
2300 } else {
2301 tp->nonagle &= ~TCP_NAGLE_CORK;
2302 if (tp->nonagle&TCP_NAGLE_OFF)
2303 tp->nonagle |= TCP_NAGLE_PUSH;
2304 tcp_push_pending_frames(sk);
2305 }
2306 break;
2307
2308 case TCP_KEEPIDLE:
2309 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2310 err = -EINVAL;
2311 else {
2312 tp->keepalive_time = val * HZ;
2313 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2314 !((1 << sk->sk_state) &
2315 (TCPF_CLOSE | TCPF_LISTEN))) {
2316 u32 elapsed = keepalive_time_elapsed(tp);
2317 if (tp->keepalive_time > elapsed)
2318 elapsed = tp->keepalive_time - elapsed;
2319 else
2320 elapsed = 0;
2321 inet_csk_reset_keepalive_timer(sk, elapsed);
2322 }
2323 }
2324 break;
2325 case TCP_KEEPINTVL:
2326 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2327 err = -EINVAL;
2328 else
2329 tp->keepalive_intvl = val * HZ;
2330 break;
2331 case TCP_KEEPCNT:
2332 if (val < 1 || val > MAX_TCP_KEEPCNT)
2333 err = -EINVAL;
2334 else
2335 tp->keepalive_probes = val;
2336 break;
2337 case TCP_SYNCNT:
2338 if (val < 1 || val > MAX_TCP_SYNCNT)
2339 err = -EINVAL;
2340 else
2341 icsk->icsk_syn_retries = val;
2342 break;
2343
2344 case TCP_LINGER2:
2345 if (val < 0)
2346 tp->linger2 = -1;
2347 else if (val > sysctl_tcp_fin_timeout / HZ)
2348 tp->linger2 = 0;
2349 else
2350 tp->linger2 = val * HZ;
2351 break;
2352
2353 case TCP_DEFER_ACCEPT:
2354 /* Translate value in seconds to number of retransmits */
2355 icsk->icsk_accept_queue.rskq_defer_accept =
2356 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2357 TCP_RTO_MAX / HZ);
2358 break;
2359
2360 case TCP_WINDOW_CLAMP:
2361 if (!val) {
2362 if (sk->sk_state != TCP_CLOSE) {
2363 err = -EINVAL;
2364 break;
2365 }
2366 tp->window_clamp = 0;
2367 } else
2368 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2369 SOCK_MIN_RCVBUF / 2 : val;
2370 break;
2371
2372 case TCP_QUICKACK:
2373 if (!val) {
2374 icsk->icsk_ack.pingpong = 1;
2375 } else {
2376 icsk->icsk_ack.pingpong = 0;
2377 if ((1 << sk->sk_state) &
2378 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2379 inet_csk_ack_scheduled(sk)) {
2380 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2381 tcp_cleanup_rbuf(sk, 1);
2382 if (!(val & 1))
2383 icsk->icsk_ack.pingpong = 1;
2384 }
2385 }
2386 break;
2387
2388#ifdef CONFIG_TCP_MD5SIG
2389 case TCP_MD5SIG:
2390 /* Read the IP->Key mappings from userspace */
2391 err = tp->af_specific->md5_parse(sk, optval, optlen);
2392 break;
2393#endif
2394 case TCP_USER_TIMEOUT:
2395 /* Cap the max timeout in ms TCP will retry/retrans
2396 * before giving up and aborting (ETIMEDOUT) a connection.
2397 */
2398 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2399 break;
2400 default:
2401 err = -ENOPROTOOPT;
2402 break;
2403 }
2404
2405 release_sock(sk);
2406 return err;
2407}
2408
2409int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2410 unsigned int optlen)
2411{
2412 struct inet_connection_sock *icsk = inet_csk(sk);
2413
2414 if (level != SOL_TCP)
2415 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2416 optval, optlen);
2417 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2418}
2419EXPORT_SYMBOL(tcp_setsockopt);
2420
2421#ifdef CONFIG_COMPAT
2422int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2423 char __user *optval, unsigned int optlen)
2424{
2425 if (level != SOL_TCP)
2426 return inet_csk_compat_setsockopt(sk, level, optname,
2427 optval, optlen);
2428 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2429}
2430EXPORT_SYMBOL(compat_tcp_setsockopt);
2431#endif
2432
2433/* Return information about state of tcp endpoint in API format. */
2434void tcp_get_info(struct sock *sk, struct tcp_info *info)
2435{
2436 struct tcp_sock *tp = tcp_sk(sk);
2437 const struct inet_connection_sock *icsk = inet_csk(sk);
2438 u32 now = tcp_time_stamp;
2439
2440 memset(info, 0, sizeof(*info));
2441
2442 info->tcpi_state = sk->sk_state;
2443 info->tcpi_ca_state = icsk->icsk_ca_state;
2444 info->tcpi_retransmits = icsk->icsk_retransmits;
2445 info->tcpi_probes = icsk->icsk_probes_out;
2446 info->tcpi_backoff = icsk->icsk_backoff;
2447
2448 if (tp->rx_opt.tstamp_ok)
2449 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2450 if (tcp_is_sack(tp))
2451 info->tcpi_options |= TCPI_OPT_SACK;
2452 if (tp->rx_opt.wscale_ok) {
2453 info->tcpi_options |= TCPI_OPT_WSCALE;
2454 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2455 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2456 }
2457
2458 if (tp->ecn_flags&TCP_ECN_OK)
2459 info->tcpi_options |= TCPI_OPT_ECN;
2460
2461 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2462 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2463 info->tcpi_snd_mss = tp->mss_cache;
2464 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2465
2466 if (sk->sk_state == TCP_LISTEN) {
2467 info->tcpi_unacked = sk->sk_ack_backlog;
2468 info->tcpi_sacked = sk->sk_max_ack_backlog;
2469 } else {
2470 info->tcpi_unacked = tp->packets_out;
2471 info->tcpi_sacked = tp->sacked_out;
2472 }
2473 info->tcpi_lost = tp->lost_out;
2474 info->tcpi_retrans = tp->retrans_out;
2475 info->tcpi_fackets = tp->fackets_out;
2476
2477 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2478 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2479 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2480
2481 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2482 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2483 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2484 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2485 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2486 info->tcpi_snd_cwnd = tp->snd_cwnd;
2487 info->tcpi_advmss = tp->advmss;
2488 info->tcpi_reordering = tp->reordering;
2489
2490 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2491 info->tcpi_rcv_space = tp->rcvq_space.space;
2492
2493 info->tcpi_total_retrans = tp->total_retrans;
2494}
2495EXPORT_SYMBOL_GPL(tcp_get_info);
2496
2497static int do_tcp_getsockopt(struct sock *sk, int level,
2498 int optname, char __user *optval, int __user *optlen)
2499{
2500 struct inet_connection_sock *icsk = inet_csk(sk);
2501 struct tcp_sock *tp = tcp_sk(sk);
2502 int val, len;
2503
2504 if (get_user(len, optlen))
2505 return -EFAULT;
2506
2507 len = min_t(unsigned int, len, sizeof(int));
2508
2509 if (len < 0)
2510 return -EINVAL;
2511
2512 switch (optname) {
2513 case TCP_MAXSEG:
2514 val = tp->mss_cache;
2515 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2516 val = tp->rx_opt.user_mss;
2517 break;
2518 case TCP_NODELAY:
2519 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2520 break;
2521 case TCP_CORK:
2522 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2523 break;
2524 case TCP_KEEPIDLE:
2525 val = keepalive_time_when(tp) / HZ;
2526 break;
2527 case TCP_KEEPINTVL:
2528 val = keepalive_intvl_when(tp) / HZ;
2529 break;
2530 case TCP_KEEPCNT:
2531 val = keepalive_probes(tp);
2532 break;
2533 case TCP_SYNCNT:
2534 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2535 break;
2536 case TCP_LINGER2:
2537 val = tp->linger2;
2538 if (val >= 0)
2539 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2540 break;
2541 case TCP_DEFER_ACCEPT:
2542 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2543 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2544 break;
2545 case TCP_WINDOW_CLAMP:
2546 val = tp->window_clamp;
2547 break;
2548 case TCP_INFO: {
2549 struct tcp_info info;
2550
2551 if (get_user(len, optlen))
2552 return -EFAULT;
2553
2554 tcp_get_info(sk, &info);
2555
2556 len = min_t(unsigned int, len, sizeof(info));
2557 if (put_user(len, optlen))
2558 return -EFAULT;
2559 if (copy_to_user(optval, &info, len))
2560 return -EFAULT;
2561 return 0;
2562 }
2563 case TCP_QUICKACK:
2564 val = !icsk->icsk_ack.pingpong;
2565 break;
2566
2567 case TCP_CONGESTION:
2568 if (get_user(len, optlen))
2569 return -EFAULT;
2570 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2571 if (put_user(len, optlen))
2572 return -EFAULT;
2573 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2574 return -EFAULT;
2575 return 0;
2576
2577 case TCP_COOKIE_TRANSACTIONS: {
2578 struct tcp_cookie_transactions ctd;
2579 struct tcp_cookie_values *cvp = tp->cookie_values;
2580
2581 if (get_user(len, optlen))
2582 return -EFAULT;
2583 if (len < sizeof(ctd))
2584 return -EINVAL;
2585
2586 memset(&ctd, 0, sizeof(ctd));
2587 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2588 TCP_COOKIE_IN_ALWAYS : 0)
2589 | (tp->rx_opt.cookie_out_never ?
2590 TCP_COOKIE_OUT_NEVER : 0);
2591
2592 if (cvp != NULL) {
2593 ctd.tcpct_flags |= (cvp->s_data_in ?
2594 TCP_S_DATA_IN : 0)
2595 | (cvp->s_data_out ?
2596 TCP_S_DATA_OUT : 0);
2597
2598 ctd.tcpct_cookie_desired = cvp->cookie_desired;
2599 ctd.tcpct_s_data_desired = cvp->s_data_desired;
2600
2601 memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2602 cvp->cookie_pair_size);
2603 ctd.tcpct_used = cvp->cookie_pair_size;
2604 }
2605
2606 if (put_user(sizeof(ctd), optlen))
2607 return -EFAULT;
2608 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2609 return -EFAULT;
2610 return 0;
2611 }
2612 case TCP_THIN_LINEAR_TIMEOUTS:
2613 val = tp->thin_lto;
2614 break;
2615 case TCP_THIN_DUPACK:
2616 val = tp->thin_dupack;
2617 break;
2618
2619 case TCP_USER_TIMEOUT:
2620 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2621 break;
2622 default:
2623 return -ENOPROTOOPT;
2624 }
2625
2626 if (put_user(len, optlen))
2627 return -EFAULT;
2628 if (copy_to_user(optval, &val, len))
2629 return -EFAULT;
2630 return 0;
2631}
2632
2633int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2634 int __user *optlen)
2635{
2636 struct inet_connection_sock *icsk = inet_csk(sk);
2637
2638 if (level != SOL_TCP)
2639 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2640 optval, optlen);
2641 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2642}
2643EXPORT_SYMBOL(tcp_getsockopt);
2644
2645#ifdef CONFIG_COMPAT
2646int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2647 char __user *optval, int __user *optlen)
2648{
2649 if (level != SOL_TCP)
2650 return inet_csk_compat_getsockopt(sk, level, optname,
2651 optval, optlen);
2652 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2653}
2654EXPORT_SYMBOL(compat_tcp_getsockopt);
2655#endif
2656
2657struct sk_buff *tcp_tso_segment(struct sk_buff *skb, u32 features)
2658{
2659 struct sk_buff *segs = ERR_PTR(-EINVAL);
2660 struct tcphdr *th;
2661 unsigned thlen;
2662 unsigned int seq;
2663 __be32 delta;
2664 unsigned int oldlen;
2665 unsigned int mss;
2666
2667 if (!pskb_may_pull(skb, sizeof(*th)))
2668 goto out;
2669
2670 th = tcp_hdr(skb);
2671 thlen = th->doff * 4;
2672 if (thlen < sizeof(*th))
2673 goto out;
2674
2675 if (!pskb_may_pull(skb, thlen))
2676 goto out;
2677
2678 oldlen = (u16)~skb->len;
2679 __skb_pull(skb, thlen);
2680
2681 mss = skb_shinfo(skb)->gso_size;
2682 if (unlikely(skb->len <= mss))
2683 goto out;
2684
2685 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2686 /* Packet is from an untrusted source, reset gso_segs. */
2687 int type = skb_shinfo(skb)->gso_type;
2688
2689 if (unlikely(type &
2690 ~(SKB_GSO_TCPV4 |
2691 SKB_GSO_DODGY |
2692 SKB_GSO_TCP_ECN |
2693 SKB_GSO_TCPV6 |
2694 0) ||
2695 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2696 goto out;
2697
2698 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2699
2700 segs = NULL;
2701 goto out;
2702 }
2703
2704 segs = skb_segment(skb, features);
2705 if (IS_ERR(segs))
2706 goto out;
2707
2708 delta = htonl(oldlen + (thlen + mss));
2709
2710 skb = segs;
2711 th = tcp_hdr(skb);
2712 seq = ntohl(th->seq);
2713
2714 do {
2715 th->fin = th->psh = 0;
2716
2717 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2718 (__force u32)delta));
2719 if (skb->ip_summed != CHECKSUM_PARTIAL)
2720 th->check =
2721 csum_fold(csum_partial(skb_transport_header(skb),
2722 thlen, skb->csum));
2723
2724 seq += mss;
2725 skb = skb->next;
2726 th = tcp_hdr(skb);
2727
2728 th->seq = htonl(seq);
2729 th->cwr = 0;
2730 } while (skb->next);
2731
2732 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2733 skb->data_len);
2734 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2735 (__force u32)delta));
2736 if (skb->ip_summed != CHECKSUM_PARTIAL)
2737 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2738 thlen, skb->csum));
2739
2740out:
2741 return segs;
2742}
2743EXPORT_SYMBOL(tcp_tso_segment);
2744
2745struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2746{
2747 struct sk_buff **pp = NULL;
2748 struct sk_buff *p;
2749 struct tcphdr *th;
2750 struct tcphdr *th2;
2751 unsigned int len;
2752 unsigned int thlen;
2753 __be32 flags;
2754 unsigned int mss = 1;
2755 unsigned int hlen;
2756 unsigned int off;
2757 int flush = 1;
2758 int i;
2759
2760 off = skb_gro_offset(skb);
2761 hlen = off + sizeof(*th);
2762 th = skb_gro_header_fast(skb, off);
2763 if (skb_gro_header_hard(skb, hlen)) {
2764 th = skb_gro_header_slow(skb, hlen, off);
2765 if (unlikely(!th))
2766 goto out;
2767 }
2768
2769 thlen = th->doff * 4;
2770 if (thlen < sizeof(*th))
2771 goto out;
2772
2773 hlen = off + thlen;
2774 if (skb_gro_header_hard(skb, hlen)) {
2775 th = skb_gro_header_slow(skb, hlen, off);
2776 if (unlikely(!th))
2777 goto out;
2778 }
2779
2780 skb_gro_pull(skb, thlen);
2781
2782 len = skb_gro_len(skb);
2783 flags = tcp_flag_word(th);
2784
2785 for (; (p = *head); head = &p->next) {
2786 if (!NAPI_GRO_CB(p)->same_flow)
2787 continue;
2788
2789 th2 = tcp_hdr(p);
2790
2791 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2792 NAPI_GRO_CB(p)->same_flow = 0;
2793 continue;
2794 }
2795
2796 goto found;
2797 }
2798
2799 goto out_check_final;
2800
2801found:
2802 flush = NAPI_GRO_CB(p)->flush;
2803 flush |= (__force int)(flags & TCP_FLAG_CWR);
2804 flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
2805 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
2806 flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
2807 for (i = sizeof(*th); i < thlen; i += 4)
2808 flush |= *(u32 *)((u8 *)th + i) ^
2809 *(u32 *)((u8 *)th2 + i);
2810
2811 mss = skb_shinfo(p)->gso_size;
2812
2813 flush |= (len - 1) >= mss;
2814 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2815
2816 if (flush || skb_gro_receive(head, skb)) {
2817 mss = 1;
2818 goto out_check_final;
2819 }
2820
2821 p = *head;
2822 th2 = tcp_hdr(p);
2823 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2824
2825out_check_final:
2826 flush = len < mss;
2827 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
2828 TCP_FLAG_RST | TCP_FLAG_SYN |
2829 TCP_FLAG_FIN));
2830
2831 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2832 pp = head;
2833
2834out:
2835 NAPI_GRO_CB(skb)->flush |= flush;
2836
2837 return pp;
2838}
2839EXPORT_SYMBOL(tcp_gro_receive);
2840
2841int tcp_gro_complete(struct sk_buff *skb)
2842{
2843 struct tcphdr *th = tcp_hdr(skb);
2844
2845 skb->csum_start = skb_transport_header(skb) - skb->head;
2846 skb->csum_offset = offsetof(struct tcphdr, check);
2847 skb->ip_summed = CHECKSUM_PARTIAL;
2848
2849 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2850
2851 if (th->cwr)
2852 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2853
2854 return 0;
2855}
2856EXPORT_SYMBOL(tcp_gro_complete);
2857
2858#ifdef CONFIG_TCP_MD5SIG
2859static unsigned long tcp_md5sig_users;
2860static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool;
2861static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2862
2863static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool)
2864{
2865 int cpu;
2866 for_each_possible_cpu(cpu) {
2867 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2868 if (p) {
2869 if (p->md5_desc.tfm)
2870 crypto_free_hash(p->md5_desc.tfm);
2871 kfree(p);
2872 }
2873 }
2874 free_percpu(pool);
2875}
2876
2877void tcp_free_md5sig_pool(void)
2878{
2879 struct tcp_md5sig_pool * __percpu *pool = NULL;
2880
2881 spin_lock_bh(&tcp_md5sig_pool_lock);
2882 if (--tcp_md5sig_users == 0) {
2883 pool = tcp_md5sig_pool;
2884 tcp_md5sig_pool = NULL;
2885 }
2886 spin_unlock_bh(&tcp_md5sig_pool_lock);
2887 if (pool)
2888 __tcp_free_md5sig_pool(pool);
2889}
2890EXPORT_SYMBOL(tcp_free_md5sig_pool);
2891
2892static struct tcp_md5sig_pool * __percpu *
2893__tcp_alloc_md5sig_pool(struct sock *sk)
2894{
2895 int cpu;
2896 struct tcp_md5sig_pool * __percpu *pool;
2897
2898 pool = alloc_percpu(struct tcp_md5sig_pool *);
2899 if (!pool)
2900 return NULL;
2901
2902 for_each_possible_cpu(cpu) {
2903 struct tcp_md5sig_pool *p;
2904 struct crypto_hash *hash;
2905
2906 p = kzalloc(sizeof(*p), sk->sk_allocation);
2907 if (!p)
2908 goto out_free;
2909 *per_cpu_ptr(pool, cpu) = p;
2910
2911 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2912 if (!hash || IS_ERR(hash))
2913 goto out_free;
2914
2915 p->md5_desc.tfm = hash;
2916 }
2917 return pool;
2918out_free:
2919 __tcp_free_md5sig_pool(pool);
2920 return NULL;
2921}
2922
2923struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
2924{
2925 struct tcp_md5sig_pool * __percpu *pool;
2926 int alloc = 0;
2927
2928retry:
2929 spin_lock_bh(&tcp_md5sig_pool_lock);
2930 pool = tcp_md5sig_pool;
2931 if (tcp_md5sig_users++ == 0) {
2932 alloc = 1;
2933 spin_unlock_bh(&tcp_md5sig_pool_lock);
2934 } else if (!pool) {
2935 tcp_md5sig_users--;
2936 spin_unlock_bh(&tcp_md5sig_pool_lock);
2937 cpu_relax();
2938 goto retry;
2939 } else
2940 spin_unlock_bh(&tcp_md5sig_pool_lock);
2941
2942 if (alloc) {
2943 /* we cannot hold spinlock here because this may sleep. */
2944 struct tcp_md5sig_pool * __percpu *p;
2945
2946 p = __tcp_alloc_md5sig_pool(sk);
2947 spin_lock_bh(&tcp_md5sig_pool_lock);
2948 if (!p) {
2949 tcp_md5sig_users--;
2950 spin_unlock_bh(&tcp_md5sig_pool_lock);
2951 return NULL;
2952 }
2953 pool = tcp_md5sig_pool;
2954 if (pool) {
2955 /* oops, it has already been assigned. */
2956 spin_unlock_bh(&tcp_md5sig_pool_lock);
2957 __tcp_free_md5sig_pool(p);
2958 } else {
2959 tcp_md5sig_pool = pool = p;
2960 spin_unlock_bh(&tcp_md5sig_pool_lock);
2961 }
2962 }
2963 return pool;
2964}
2965EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2966
2967
2968/**
2969 * tcp_get_md5sig_pool - get md5sig_pool for this user
2970 *
2971 * We use percpu structure, so if we succeed, we exit with preemption
2972 * and BH disabled, to make sure another thread or softirq handling
2973 * wont try to get same context.
2974 */
2975struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2976{
2977 struct tcp_md5sig_pool * __percpu *p;
2978
2979 local_bh_disable();
2980
2981 spin_lock(&tcp_md5sig_pool_lock);
2982 p = tcp_md5sig_pool;
2983 if (p)
2984 tcp_md5sig_users++;
2985 spin_unlock(&tcp_md5sig_pool_lock);
2986
2987 if (p)
2988 return *this_cpu_ptr(p);
2989
2990 local_bh_enable();
2991 return NULL;
2992}
2993EXPORT_SYMBOL(tcp_get_md5sig_pool);
2994
2995void tcp_put_md5sig_pool(void)
2996{
2997 local_bh_enable();
2998 tcp_free_md5sig_pool();
2999}
3000EXPORT_SYMBOL(tcp_put_md5sig_pool);
3001
3002int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3003 struct tcphdr *th)
3004{
3005 struct scatterlist sg;
3006 int err;
3007
3008 __sum16 old_checksum = th->check;
3009 th->check = 0;
3010 /* options aren't included in the hash */
3011 sg_init_one(&sg, th, sizeof(struct tcphdr));
3012 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
3013 th->check = old_checksum;
3014 return err;
3015}
3016EXPORT_SYMBOL(tcp_md5_hash_header);
3017
3018int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3019 struct sk_buff *skb, unsigned header_len)
3020{
3021 struct scatterlist sg;
3022 const struct tcphdr *tp = tcp_hdr(skb);
3023 struct hash_desc *desc = &hp->md5_desc;
3024 unsigned i;
3025 const unsigned head_data_len = skb_headlen(skb) > header_len ?
3026 skb_headlen(skb) - header_len : 0;
3027 const struct skb_shared_info *shi = skb_shinfo(skb);
3028 struct sk_buff *frag_iter;
3029
3030 sg_init_table(&sg, 1);
3031
3032 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3033 if (crypto_hash_update(desc, &sg, head_data_len))
3034 return 1;
3035
3036 for (i = 0; i < shi->nr_frags; ++i) {
3037 const struct skb_frag_struct *f = &shi->frags[i];
3038 sg_set_page(&sg, f->page, f->size, f->page_offset);
3039 if (crypto_hash_update(desc, &sg, f->size))
3040 return 1;
3041 }
3042
3043 skb_walk_frags(skb, frag_iter)
3044 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3045 return 1;
3046
3047 return 0;
3048}
3049EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3050
3051int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
3052{
3053 struct scatterlist sg;
3054
3055 sg_init_one(&sg, key->key, key->keylen);
3056 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3057}
3058EXPORT_SYMBOL(tcp_md5_hash_key);
3059
3060#endif
3061
3062/**
3063 * Each Responder maintains up to two secret values concurrently for
3064 * efficient secret rollover. Each secret value has 4 states:
3065 *
3066 * Generating. (tcp_secret_generating != tcp_secret_primary)
3067 * Generates new Responder-Cookies, but not yet used for primary
3068 * verification. This is a short-term state, typically lasting only
3069 * one round trip time (RTT).
3070 *
3071 * Primary. (tcp_secret_generating == tcp_secret_primary)
3072 * Used both for generation and primary verification.
3073 *
3074 * Retiring. (tcp_secret_retiring != tcp_secret_secondary)
3075 * Used for verification, until the first failure that can be
3076 * verified by the newer Generating secret. At that time, this
3077 * cookie's state is changed to Secondary, and the Generating
3078 * cookie's state is changed to Primary. This is a short-term state,
3079 * typically lasting only one round trip time (RTT).
3080 *
3081 * Secondary. (tcp_secret_retiring == tcp_secret_secondary)
3082 * Used for secondary verification, after primary verification
3083 * failures. This state lasts no more than twice the Maximum Segment
3084 * Lifetime (2MSL). Then, the secret is discarded.
3085 */
3086struct tcp_cookie_secret {
3087 /* The secret is divided into two parts. The digest part is the
3088 * equivalent of previously hashing a secret and saving the state,
3089 * and serves as an initialization vector (IV). The message part
3090 * serves as the trailing secret.
3091 */
3092 u32 secrets[COOKIE_WORKSPACE_WORDS];
3093 unsigned long expires;
3094};
3095
3096#define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3097#define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3098#define TCP_SECRET_LIFE (HZ * 600)
3099
3100static struct tcp_cookie_secret tcp_secret_one;
3101static struct tcp_cookie_secret tcp_secret_two;
3102
3103/* Essentially a circular list, without dynamic allocation. */
3104static struct tcp_cookie_secret *tcp_secret_generating;
3105static struct tcp_cookie_secret *tcp_secret_primary;
3106static struct tcp_cookie_secret *tcp_secret_retiring;
3107static struct tcp_cookie_secret *tcp_secret_secondary;
3108
3109static DEFINE_SPINLOCK(tcp_secret_locker);
3110
3111/* Select a pseudo-random word in the cookie workspace.
3112 */
3113static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3114{
3115 return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3116}
3117
3118/* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3119 * Called in softirq context.
3120 * Returns: 0 for success.
3121 */
3122int tcp_cookie_generator(u32 *bakery)
3123{
3124 unsigned long jiffy = jiffies;
3125
3126 if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3127 spin_lock_bh(&tcp_secret_locker);
3128 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3129 /* refreshed by another */
3130 memcpy(bakery,
3131 &tcp_secret_generating->secrets[0],
3132 COOKIE_WORKSPACE_WORDS);
3133 } else {
3134 /* still needs refreshing */
3135 get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3136
3137 /* The first time, paranoia assumes that the
3138 * randomization function isn't as strong. But,
3139 * this secret initialization is delayed until
3140 * the last possible moment (packet arrival).
3141 * Although that time is observable, it is
3142 * unpredictably variable. Mash in the most
3143 * volatile clock bits available, and expire the
3144 * secret extra quickly.
3145 */
3146 if (unlikely(tcp_secret_primary->expires ==
3147 tcp_secret_secondary->expires)) {
3148 struct timespec tv;
3149
3150 getnstimeofday(&tv);
3151 bakery[COOKIE_DIGEST_WORDS+0] ^=
3152 (u32)tv.tv_nsec;
3153
3154 tcp_secret_secondary->expires = jiffy
3155 + TCP_SECRET_1MSL
3156 + (0x0f & tcp_cookie_work(bakery, 0));
3157 } else {
3158 tcp_secret_secondary->expires = jiffy
3159 + TCP_SECRET_LIFE
3160 + (0xff & tcp_cookie_work(bakery, 1));
3161 tcp_secret_primary->expires = jiffy
3162 + TCP_SECRET_2MSL
3163 + (0x1f & tcp_cookie_work(bakery, 2));
3164 }
3165 memcpy(&tcp_secret_secondary->secrets[0],
3166 bakery, COOKIE_WORKSPACE_WORDS);
3167
3168 rcu_assign_pointer(tcp_secret_generating,
3169 tcp_secret_secondary);
3170 rcu_assign_pointer(tcp_secret_retiring,
3171 tcp_secret_primary);
3172 /*
3173 * Neither call_rcu() nor synchronize_rcu() needed.
3174 * Retiring data is not freed. It is replaced after
3175 * further (locked) pointer updates, and a quiet time
3176 * (minimum 1MSL, maximum LIFE - 2MSL).
3177 */
3178 }
3179 spin_unlock_bh(&tcp_secret_locker);
3180 } else {
3181 rcu_read_lock_bh();
3182 memcpy(bakery,
3183 &rcu_dereference(tcp_secret_generating)->secrets[0],
3184 COOKIE_WORKSPACE_WORDS);
3185 rcu_read_unlock_bh();
3186 }
3187 return 0;
3188}
3189EXPORT_SYMBOL(tcp_cookie_generator);
3190
3191void tcp_done(struct sock *sk)
3192{
3193 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3194 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3195
3196 tcp_set_state(sk, TCP_CLOSE);
3197 tcp_clear_xmit_timers(sk);
3198
3199 sk->sk_shutdown = SHUTDOWN_MASK;
3200
3201 if (!sock_flag(sk, SOCK_DEAD))
3202 sk->sk_state_change(sk);
3203 else
3204 inet_csk_destroy_sock(sk);
3205}
3206EXPORT_SYMBOL_GPL(tcp_done);
3207
3208extern struct tcp_congestion_ops tcp_reno;
3209
3210static __initdata unsigned long thash_entries;
3211static int __init set_thash_entries(char *str)
3212{
3213 if (!str)
3214 return 0;
3215 thash_entries = simple_strtoul(str, &str, 0);
3216 return 1;
3217}
3218__setup("thash_entries=", set_thash_entries);
3219
3220void __init tcp_init(void)
3221{
3222 struct sk_buff *skb = NULL;
3223 unsigned long limit;
3224 int i, max_share, cnt;
3225 unsigned long jiffy = jiffies;
3226
3227 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3228
3229 percpu_counter_init(&tcp_sockets_allocated, 0);
3230 percpu_counter_init(&tcp_orphan_count, 0);
3231 tcp_hashinfo.bind_bucket_cachep =
3232 kmem_cache_create("tcp_bind_bucket",
3233 sizeof(struct inet_bind_bucket), 0,
3234 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3235
3236 /* Size and allocate the main established and bind bucket
3237 * hash tables.
3238 *
3239 * The methodology is similar to that of the buffer cache.
3240 */
3241 tcp_hashinfo.ehash =
3242 alloc_large_system_hash("TCP established",
3243 sizeof(struct inet_ehash_bucket),
3244 thash_entries,
3245 (totalram_pages >= 128 * 1024) ?
3246 13 : 15,
3247 0,
3248 NULL,
3249 &tcp_hashinfo.ehash_mask,
3250 thash_entries ? 0 : 512 * 1024);
3251 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3252 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3253 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3254 }
3255 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3256 panic("TCP: failed to alloc ehash_locks");
3257 tcp_hashinfo.bhash =
3258 alloc_large_system_hash("TCP bind",
3259 sizeof(struct inet_bind_hashbucket),
3260 tcp_hashinfo.ehash_mask + 1,
3261 (totalram_pages >= 128 * 1024) ?
3262 13 : 15,
3263 0,
3264 &tcp_hashinfo.bhash_size,
3265 NULL,
3266 64 * 1024);
3267 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
3268 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3269 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3270 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3271 }
3272
3273
3274 cnt = tcp_hashinfo.ehash_mask + 1;
3275
3276 tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3277 sysctl_tcp_max_orphans = cnt / 2;
3278 sysctl_max_syn_backlog = max(128, cnt / 256);
3279
3280 limit = nr_free_buffer_pages() / 8;
3281 limit = max(limit, 128UL);
3282 sysctl_tcp_mem[0] = limit / 4 * 3;
3283 sysctl_tcp_mem[1] = limit;
3284 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3285
3286 /* Set per-socket limits to no more than 1/128 the pressure threshold */
3287 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
3288 max_share = min(4UL*1024*1024, limit);
3289
3290 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3291 sysctl_tcp_wmem[1] = 16*1024;
3292 sysctl_tcp_wmem[2] = max(64*1024, max_share);
3293
3294 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3295 sysctl_tcp_rmem[1] = 87380;
3296 sysctl_tcp_rmem[2] = max(87380, max_share);
3297
3298 printk(KERN_INFO "TCP: Hash tables configured "
3299 "(established %u bind %u)\n",
3300 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3301
3302 tcp_register_congestion_control(&tcp_reno);
3303
3304 memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3305 memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3306 tcp_secret_one.expires = jiffy; /* past due */
3307 tcp_secret_two.expires = jiffy; /* past due */
3308 tcp_secret_generating = &tcp_secret_one;
3309 tcp_secret_primary = &tcp_secret_one;
3310 tcp_secret_retiring = &tcp_secret_two;
3311 tcp_secret_secondary = &tcp_secret_two;
3312}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * Authors: Ross Biro
10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11 * Mark Evans, <evansmp@uhura.aston.ac.uk>
12 * Corey Minyard <wf-rch!minyard@relay.EU.net>
13 * Florian La Roche, <flla@stud.uni-sb.de>
14 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
15 * Linus Torvalds, <torvalds@cs.helsinki.fi>
16 * Alan Cox, <gw4pts@gw4pts.ampr.org>
17 * Matthew Dillon, <dillon@apollo.west.oic.com>
18 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
19 * Jorge Cwik, <jorge@laser.satlink.net>
20 *
21 * Fixes:
22 * Alan Cox : Numerous verify_area() calls
23 * Alan Cox : Set the ACK bit on a reset
24 * Alan Cox : Stopped it crashing if it closed while
25 * sk->inuse=1 and was trying to connect
26 * (tcp_err()).
27 * Alan Cox : All icmp error handling was broken
28 * pointers passed where wrong and the
29 * socket was looked up backwards. Nobody
30 * tested any icmp error code obviously.
31 * Alan Cox : tcp_err() now handled properly. It
32 * wakes people on errors. poll
33 * behaves and the icmp error race
34 * has gone by moving it into sock.c
35 * Alan Cox : tcp_send_reset() fixed to work for
36 * everything not just packets for
37 * unknown sockets.
38 * Alan Cox : tcp option processing.
39 * Alan Cox : Reset tweaked (still not 100%) [Had
40 * syn rule wrong]
41 * Herp Rosmanith : More reset fixes
42 * Alan Cox : No longer acks invalid rst frames.
43 * Acking any kind of RST is right out.
44 * Alan Cox : Sets an ignore me flag on an rst
45 * receive otherwise odd bits of prattle
46 * escape still
47 * Alan Cox : Fixed another acking RST frame bug.
48 * Should stop LAN workplace lockups.
49 * Alan Cox : Some tidyups using the new skb list
50 * facilities
51 * Alan Cox : sk->keepopen now seems to work
52 * Alan Cox : Pulls options out correctly on accepts
53 * Alan Cox : Fixed assorted sk->rqueue->next errors
54 * Alan Cox : PSH doesn't end a TCP read. Switched a
55 * bit to skb ops.
56 * Alan Cox : Tidied tcp_data to avoid a potential
57 * nasty.
58 * Alan Cox : Added some better commenting, as the
59 * tcp is hard to follow
60 * Alan Cox : Removed incorrect check for 20 * psh
61 * Michael O'Reilly : ack < copied bug fix.
62 * Johannes Stille : Misc tcp fixes (not all in yet).
63 * Alan Cox : FIN with no memory -> CRASH
64 * Alan Cox : Added socket option proto entries.
65 * Also added awareness of them to accept.
66 * Alan Cox : Added TCP options (SOL_TCP)
67 * Alan Cox : Switched wakeup calls to callbacks,
68 * so the kernel can layer network
69 * sockets.
70 * Alan Cox : Use ip_tos/ip_ttl settings.
71 * Alan Cox : Handle FIN (more) properly (we hope).
72 * Alan Cox : RST frames sent on unsynchronised
73 * state ack error.
74 * Alan Cox : Put in missing check for SYN bit.
75 * Alan Cox : Added tcp_select_window() aka NET2E
76 * window non shrink trick.
77 * Alan Cox : Added a couple of small NET2E timer
78 * fixes
79 * Charles Hedrick : TCP fixes
80 * Toomas Tamm : TCP window fixes
81 * Alan Cox : Small URG fix to rlogin ^C ack fight
82 * Charles Hedrick : Rewrote most of it to actually work
83 * Linus : Rewrote tcp_read() and URG handling
84 * completely
85 * Gerhard Koerting: Fixed some missing timer handling
86 * Matthew Dillon : Reworked TCP machine states as per RFC
87 * Gerhard Koerting: PC/TCP workarounds
88 * Adam Caldwell : Assorted timer/timing errors
89 * Matthew Dillon : Fixed another RST bug
90 * Alan Cox : Move to kernel side addressing changes.
91 * Alan Cox : Beginning work on TCP fastpathing
92 * (not yet usable)
93 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
94 * Alan Cox : TCP fast path debugging
95 * Alan Cox : Window clamping
96 * Michael Riepe : Bug in tcp_check()
97 * Matt Dillon : More TCP improvements and RST bug fixes
98 * Matt Dillon : Yet more small nasties remove from the
99 * TCP code (Be very nice to this man if
100 * tcp finally works 100%) 8)
101 * Alan Cox : BSD accept semantics.
102 * Alan Cox : Reset on closedown bug.
103 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
104 * Michael Pall : Handle poll() after URG properly in
105 * all cases.
106 * Michael Pall : Undo the last fix in tcp_read_urg()
107 * (multi URG PUSH broke rlogin).
108 * Michael Pall : Fix the multi URG PUSH problem in
109 * tcp_readable(), poll() after URG
110 * works now.
111 * Michael Pall : recv(...,MSG_OOB) never blocks in the
112 * BSD api.
113 * Alan Cox : Changed the semantics of sk->socket to
114 * fix a race and a signal problem with
115 * accept() and async I/O.
116 * Alan Cox : Relaxed the rules on tcp_sendto().
117 * Yury Shevchuk : Really fixed accept() blocking problem.
118 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
119 * clients/servers which listen in on
120 * fixed ports.
121 * Alan Cox : Cleaned the above up and shrank it to
122 * a sensible code size.
123 * Alan Cox : Self connect lockup fix.
124 * Alan Cox : No connect to multicast.
125 * Ross Biro : Close unaccepted children on master
126 * socket close.
127 * Alan Cox : Reset tracing code.
128 * Alan Cox : Spurious resets on shutdown.
129 * Alan Cox : Giant 15 minute/60 second timer error
130 * Alan Cox : Small whoops in polling before an
131 * accept.
132 * Alan Cox : Kept the state trace facility since
133 * it's handy for debugging.
134 * Alan Cox : More reset handler fixes.
135 * Alan Cox : Started rewriting the code based on
136 * the RFC's for other useful protocol
137 * references see: Comer, KA9Q NOS, and
138 * for a reference on the difference
139 * between specifications and how BSD
140 * works see the 4.4lite source.
141 * A.N.Kuznetsov : Don't time wait on completion of tidy
142 * close.
143 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
144 * Linus Torvalds : Fixed BSD port reuse to work first syn
145 * Alan Cox : Reimplemented timers as per the RFC
146 * and using multiple timers for sanity.
147 * Alan Cox : Small bug fixes, and a lot of new
148 * comments.
149 * Alan Cox : Fixed dual reader crash by locking
150 * the buffers (much like datagram.c)
151 * Alan Cox : Fixed stuck sockets in probe. A probe
152 * now gets fed up of retrying without
153 * (even a no space) answer.
154 * Alan Cox : Extracted closing code better
155 * Alan Cox : Fixed the closing state machine to
156 * resemble the RFC.
157 * Alan Cox : More 'per spec' fixes.
158 * Jorge Cwik : Even faster checksumming.
159 * Alan Cox : tcp_data() doesn't ack illegal PSH
160 * only frames. At least one pc tcp stack
161 * generates them.
162 * Alan Cox : Cache last socket.
163 * Alan Cox : Per route irtt.
164 * Matt Day : poll()->select() match BSD precisely on error
165 * Alan Cox : New buffers
166 * Marc Tamsky : Various sk->prot->retransmits and
167 * sk->retransmits misupdating fixed.
168 * Fixed tcp_write_timeout: stuck close,
169 * and TCP syn retries gets used now.
170 * Mark Yarvis : In tcp_read_wakeup(), don't send an
171 * ack if state is TCP_CLOSED.
172 * Alan Cox : Look up device on a retransmit - routes may
173 * change. Doesn't yet cope with MSS shrink right
174 * but it's a start!
175 * Marc Tamsky : Closing in closing fixes.
176 * Mike Shaver : RFC1122 verifications.
177 * Alan Cox : rcv_saddr errors.
178 * Alan Cox : Block double connect().
179 * Alan Cox : Small hooks for enSKIP.
180 * Alexey Kuznetsov: Path MTU discovery.
181 * Alan Cox : Support soft errors.
182 * Alan Cox : Fix MTU discovery pathological case
183 * when the remote claims no mtu!
184 * Marc Tamsky : TCP_CLOSE fix.
185 * Colin (G3TNE) : Send a reset on syn ack replies in
186 * window but wrong (fixes NT lpd problems)
187 * Pedro Roque : Better TCP window handling, delayed ack.
188 * Joerg Reuter : No modification of locked buffers in
189 * tcp_do_retransmit()
190 * Eric Schenk : Changed receiver side silly window
191 * avoidance algorithm to BSD style
192 * algorithm. This doubles throughput
193 * against machines running Solaris,
194 * and seems to result in general
195 * improvement.
196 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
197 * Willy Konynenberg : Transparent proxying support.
198 * Mike McLagan : Routing by source
199 * Keith Owens : Do proper merging with partial SKB's in
200 * tcp_do_sendmsg to avoid burstiness.
201 * Eric Schenk : Fix fast close down bug with
202 * shutdown() followed by close().
203 * Andi Kleen : Make poll agree with SIGIO
204 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
205 * lingertime == 0 (RFC 793 ABORT Call)
206 * Hirokazu Takahashi : Use copy_from_user() instead of
207 * csum_and_copy_from_user() if possible.
208 *
209 * Description of States:
210 *
211 * TCP_SYN_SENT sent a connection request, waiting for ack
212 *
213 * TCP_SYN_RECV received a connection request, sent ack,
214 * waiting for final ack in three-way handshake.
215 *
216 * TCP_ESTABLISHED connection established
217 *
218 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
219 * transmission of remaining buffered data
220 *
221 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
222 * to shutdown
223 *
224 * TCP_CLOSING both sides have shutdown but we still have
225 * data we have to finish sending
226 *
227 * TCP_TIME_WAIT timeout to catch resent junk before entering
228 * closed, can only be entered from FIN_WAIT2
229 * or CLOSING. Required because the other end
230 * may not have gotten our last ACK causing it
231 * to retransmit the data packet (which we ignore)
232 *
233 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
234 * us to finish writing our data and to shutdown
235 * (we have to close() to move on to LAST_ACK)
236 *
237 * TCP_LAST_ACK out side has shutdown after remote has
238 * shutdown. There may still be data in our
239 * buffer that we have to finish sending
240 *
241 * TCP_CLOSE socket is finished
242 */
243
244#define pr_fmt(fmt) "TCP: " fmt
245
246#include <crypto/hash.h>
247#include <linux/kernel.h>
248#include <linux/module.h>
249#include <linux/types.h>
250#include <linux/fcntl.h>
251#include <linux/poll.h>
252#include <linux/inet_diag.h>
253#include <linux/init.h>
254#include <linux/fs.h>
255#include <linux/skbuff.h>
256#include <linux/scatterlist.h>
257#include <linux/splice.h>
258#include <linux/net.h>
259#include <linux/socket.h>
260#include <linux/random.h>
261#include <linux/memblock.h>
262#include <linux/highmem.h>
263#include <linux/swap.h>
264#include <linux/cache.h>
265#include <linux/err.h>
266#include <linux/time.h>
267#include <linux/slab.h>
268#include <linux/errqueue.h>
269#include <linux/static_key.h>
270
271#include <net/icmp.h>
272#include <net/inet_common.h>
273#include <net/tcp.h>
274#include <net/xfrm.h>
275#include <net/ip.h>
276#include <net/sock.h>
277
278#include <linux/uaccess.h>
279#include <asm/ioctls.h>
280#include <net/busy_poll.h>
281
282struct percpu_counter tcp_orphan_count;
283EXPORT_SYMBOL_GPL(tcp_orphan_count);
284
285long sysctl_tcp_mem[3] __read_mostly;
286EXPORT_SYMBOL(sysctl_tcp_mem);
287
288atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
289EXPORT_SYMBOL(tcp_memory_allocated);
290
291#if IS_ENABLED(CONFIG_SMC)
292DEFINE_STATIC_KEY_FALSE(tcp_have_smc);
293EXPORT_SYMBOL(tcp_have_smc);
294#endif
295
296/*
297 * Current number of TCP sockets.
298 */
299struct percpu_counter tcp_sockets_allocated;
300EXPORT_SYMBOL(tcp_sockets_allocated);
301
302/*
303 * TCP splice context
304 */
305struct tcp_splice_state {
306 struct pipe_inode_info *pipe;
307 size_t len;
308 unsigned int flags;
309};
310
311/*
312 * Pressure flag: try to collapse.
313 * Technical note: it is used by multiple contexts non atomically.
314 * All the __sk_mem_schedule() is of this nature: accounting
315 * is strict, actions are advisory and have some latency.
316 */
317unsigned long tcp_memory_pressure __read_mostly;
318EXPORT_SYMBOL_GPL(tcp_memory_pressure);
319
320DEFINE_STATIC_KEY_FALSE(tcp_rx_skb_cache_key);
321EXPORT_SYMBOL(tcp_rx_skb_cache_key);
322
323DEFINE_STATIC_KEY_FALSE(tcp_tx_skb_cache_key);
324
325void tcp_enter_memory_pressure(struct sock *sk)
326{
327 unsigned long val;
328
329 if (READ_ONCE(tcp_memory_pressure))
330 return;
331 val = jiffies;
332
333 if (!val)
334 val--;
335 if (!cmpxchg(&tcp_memory_pressure, 0, val))
336 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
337}
338EXPORT_SYMBOL_GPL(tcp_enter_memory_pressure);
339
340void tcp_leave_memory_pressure(struct sock *sk)
341{
342 unsigned long val;
343
344 if (!READ_ONCE(tcp_memory_pressure))
345 return;
346 val = xchg(&tcp_memory_pressure, 0);
347 if (val)
348 NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURESCHRONO,
349 jiffies_to_msecs(jiffies - val));
350}
351EXPORT_SYMBOL_GPL(tcp_leave_memory_pressure);
352
353/* Convert seconds to retransmits based on initial and max timeout */
354static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
355{
356 u8 res = 0;
357
358 if (seconds > 0) {
359 int period = timeout;
360
361 res = 1;
362 while (seconds > period && res < 255) {
363 res++;
364 timeout <<= 1;
365 if (timeout > rto_max)
366 timeout = rto_max;
367 period += timeout;
368 }
369 }
370 return res;
371}
372
373/* Convert retransmits to seconds based on initial and max timeout */
374static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
375{
376 int period = 0;
377
378 if (retrans > 0) {
379 period = timeout;
380 while (--retrans) {
381 timeout <<= 1;
382 if (timeout > rto_max)
383 timeout = rto_max;
384 period += timeout;
385 }
386 }
387 return period;
388}
389
390static u64 tcp_compute_delivery_rate(const struct tcp_sock *tp)
391{
392 u32 rate = READ_ONCE(tp->rate_delivered);
393 u32 intv = READ_ONCE(tp->rate_interval_us);
394 u64 rate64 = 0;
395
396 if (rate && intv) {
397 rate64 = (u64)rate * tp->mss_cache * USEC_PER_SEC;
398 do_div(rate64, intv);
399 }
400 return rate64;
401}
402
403/* Address-family independent initialization for a tcp_sock.
404 *
405 * NOTE: A lot of things set to zero explicitly by call to
406 * sk_alloc() so need not be done here.
407 */
408void tcp_init_sock(struct sock *sk)
409{
410 struct inet_connection_sock *icsk = inet_csk(sk);
411 struct tcp_sock *tp = tcp_sk(sk);
412
413 tp->out_of_order_queue = RB_ROOT;
414 sk->tcp_rtx_queue = RB_ROOT;
415 tcp_init_xmit_timers(sk);
416 INIT_LIST_HEAD(&tp->tsq_node);
417 INIT_LIST_HEAD(&tp->tsorted_sent_queue);
418
419 icsk->icsk_rto = TCP_TIMEOUT_INIT;
420 tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
421 minmax_reset(&tp->rtt_min, tcp_jiffies32, ~0U);
422
423 /* So many TCP implementations out there (incorrectly) count the
424 * initial SYN frame in their delayed-ACK and congestion control
425 * algorithms that we must have the following bandaid to talk
426 * efficiently to them. -DaveM
427 */
428 tp->snd_cwnd = TCP_INIT_CWND;
429
430 /* There's a bubble in the pipe until at least the first ACK. */
431 tp->app_limited = ~0U;
432
433 /* See draft-stevens-tcpca-spec-01 for discussion of the
434 * initialization of these values.
435 */
436 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
437 tp->snd_cwnd_clamp = ~0;
438 tp->mss_cache = TCP_MSS_DEFAULT;
439
440 tp->reordering = sock_net(sk)->ipv4.sysctl_tcp_reordering;
441 tcp_assign_congestion_control(sk);
442
443 tp->tsoffset = 0;
444 tp->rack.reo_wnd_steps = 1;
445
446 sk->sk_state = TCP_CLOSE;
447
448 sk->sk_write_space = sk_stream_write_space;
449 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
450
451 icsk->icsk_sync_mss = tcp_sync_mss;
452
453 WRITE_ONCE(sk->sk_sndbuf, sock_net(sk)->ipv4.sysctl_tcp_wmem[1]);
454 WRITE_ONCE(sk->sk_rcvbuf, sock_net(sk)->ipv4.sysctl_tcp_rmem[1]);
455
456 sk_sockets_allocated_inc(sk);
457 sk->sk_route_forced_caps = NETIF_F_GSO;
458}
459EXPORT_SYMBOL(tcp_init_sock);
460
461static void tcp_tx_timestamp(struct sock *sk, u16 tsflags)
462{
463 struct sk_buff *skb = tcp_write_queue_tail(sk);
464
465 if (tsflags && skb) {
466 struct skb_shared_info *shinfo = skb_shinfo(skb);
467 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
468
469 sock_tx_timestamp(sk, tsflags, &shinfo->tx_flags);
470 if (tsflags & SOF_TIMESTAMPING_TX_ACK)
471 tcb->txstamp_ack = 1;
472 if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
473 shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
474 }
475}
476
477static inline bool tcp_stream_is_readable(const struct tcp_sock *tp,
478 int target, struct sock *sk)
479{
480 return (READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq) >= target) ||
481 (sk->sk_prot->stream_memory_read ?
482 sk->sk_prot->stream_memory_read(sk) : false);
483}
484
485/*
486 * Wait for a TCP event.
487 *
488 * Note that we don't need to lock the socket, as the upper poll layers
489 * take care of normal races (between the test and the event) and we don't
490 * go look at any of the socket buffers directly.
491 */
492__poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
493{
494 __poll_t mask;
495 struct sock *sk = sock->sk;
496 const struct tcp_sock *tp = tcp_sk(sk);
497 int state;
498
499 sock_poll_wait(file, sock, wait);
500
501 state = inet_sk_state_load(sk);
502 if (state == TCP_LISTEN)
503 return inet_csk_listen_poll(sk);
504
505 /* Socket is not locked. We are protected from async events
506 * by poll logic and correct handling of state changes
507 * made by other threads is impossible in any case.
508 */
509
510 mask = 0;
511
512 /*
513 * EPOLLHUP is certainly not done right. But poll() doesn't
514 * have a notion of HUP in just one direction, and for a
515 * socket the read side is more interesting.
516 *
517 * Some poll() documentation says that EPOLLHUP is incompatible
518 * with the EPOLLOUT/POLLWR flags, so somebody should check this
519 * all. But careful, it tends to be safer to return too many
520 * bits than too few, and you can easily break real applications
521 * if you don't tell them that something has hung up!
522 *
523 * Check-me.
524 *
525 * Check number 1. EPOLLHUP is _UNMASKABLE_ event (see UNIX98 and
526 * our fs/select.c). It means that after we received EOF,
527 * poll always returns immediately, making impossible poll() on write()
528 * in state CLOSE_WAIT. One solution is evident --- to set EPOLLHUP
529 * if and only if shutdown has been made in both directions.
530 * Actually, it is interesting to look how Solaris and DUX
531 * solve this dilemma. I would prefer, if EPOLLHUP were maskable,
532 * then we could set it on SND_SHUTDOWN. BTW examples given
533 * in Stevens' books assume exactly this behaviour, it explains
534 * why EPOLLHUP is incompatible with EPOLLOUT. --ANK
535 *
536 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
537 * blocking on fresh not-connected or disconnected socket. --ANK
538 */
539 if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
540 mask |= EPOLLHUP;
541 if (sk->sk_shutdown & RCV_SHUTDOWN)
542 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
543
544 /* Connected or passive Fast Open socket? */
545 if (state != TCP_SYN_SENT &&
546 (state != TCP_SYN_RECV || rcu_access_pointer(tp->fastopen_rsk))) {
547 int target = sock_rcvlowat(sk, 0, INT_MAX);
548
549 if (READ_ONCE(tp->urg_seq) == READ_ONCE(tp->copied_seq) &&
550 !sock_flag(sk, SOCK_URGINLINE) &&
551 tp->urg_data)
552 target++;
553
554 if (tcp_stream_is_readable(tp, target, sk))
555 mask |= EPOLLIN | EPOLLRDNORM;
556
557 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
558 if (sk_stream_is_writeable(sk)) {
559 mask |= EPOLLOUT | EPOLLWRNORM;
560 } else { /* send SIGIO later */
561 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
562 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
563
564 /* Race breaker. If space is freed after
565 * wspace test but before the flags are set,
566 * IO signal will be lost. Memory barrier
567 * pairs with the input side.
568 */
569 smp_mb__after_atomic();
570 if (sk_stream_is_writeable(sk))
571 mask |= EPOLLOUT | EPOLLWRNORM;
572 }
573 } else
574 mask |= EPOLLOUT | EPOLLWRNORM;
575
576 if (tp->urg_data & TCP_URG_VALID)
577 mask |= EPOLLPRI;
578 } else if (state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) {
579 /* Active TCP fastopen socket with defer_connect
580 * Return EPOLLOUT so application can call write()
581 * in order for kernel to generate SYN+data
582 */
583 mask |= EPOLLOUT | EPOLLWRNORM;
584 }
585 /* This barrier is coupled with smp_wmb() in tcp_reset() */
586 smp_rmb();
587 if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
588 mask |= EPOLLERR;
589
590 return mask;
591}
592EXPORT_SYMBOL(tcp_poll);
593
594int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
595{
596 struct tcp_sock *tp = tcp_sk(sk);
597 int answ;
598 bool slow;
599
600 switch (cmd) {
601 case SIOCINQ:
602 if (sk->sk_state == TCP_LISTEN)
603 return -EINVAL;
604
605 slow = lock_sock_fast(sk);
606 answ = tcp_inq(sk);
607 unlock_sock_fast(sk, slow);
608 break;
609 case SIOCATMARK:
610 answ = tp->urg_data &&
611 READ_ONCE(tp->urg_seq) == READ_ONCE(tp->copied_seq);
612 break;
613 case SIOCOUTQ:
614 if (sk->sk_state == TCP_LISTEN)
615 return -EINVAL;
616
617 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
618 answ = 0;
619 else
620 answ = READ_ONCE(tp->write_seq) - tp->snd_una;
621 break;
622 case SIOCOUTQNSD:
623 if (sk->sk_state == TCP_LISTEN)
624 return -EINVAL;
625
626 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
627 answ = 0;
628 else
629 answ = READ_ONCE(tp->write_seq) -
630 READ_ONCE(tp->snd_nxt);
631 break;
632 default:
633 return -ENOIOCTLCMD;
634 }
635
636 return put_user(answ, (int __user *)arg);
637}
638EXPORT_SYMBOL(tcp_ioctl);
639
640static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
641{
642 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
643 tp->pushed_seq = tp->write_seq;
644}
645
646static inline bool forced_push(const struct tcp_sock *tp)
647{
648 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
649}
650
651static void skb_entail(struct sock *sk, struct sk_buff *skb)
652{
653 struct tcp_sock *tp = tcp_sk(sk);
654 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
655
656 skb->csum = 0;
657 tcb->seq = tcb->end_seq = tp->write_seq;
658 tcb->tcp_flags = TCPHDR_ACK;
659 tcb->sacked = 0;
660 __skb_header_release(skb);
661 tcp_add_write_queue_tail(sk, skb);
662 sk_wmem_queued_add(sk, skb->truesize);
663 sk_mem_charge(sk, skb->truesize);
664 if (tp->nonagle & TCP_NAGLE_PUSH)
665 tp->nonagle &= ~TCP_NAGLE_PUSH;
666
667 tcp_slow_start_after_idle_check(sk);
668}
669
670static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
671{
672 if (flags & MSG_OOB)
673 tp->snd_up = tp->write_seq;
674}
675
676/* If a not yet filled skb is pushed, do not send it if
677 * we have data packets in Qdisc or NIC queues :
678 * Because TX completion will happen shortly, it gives a chance
679 * to coalesce future sendmsg() payload into this skb, without
680 * need for a timer, and with no latency trade off.
681 * As packets containing data payload have a bigger truesize
682 * than pure acks (dataless) packets, the last checks prevent
683 * autocorking if we only have an ACK in Qdisc/NIC queues,
684 * or if TX completion was delayed after we processed ACK packet.
685 */
686static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
687 int size_goal)
688{
689 return skb->len < size_goal &&
690 sock_net(sk)->ipv4.sysctl_tcp_autocorking &&
691 !tcp_rtx_queue_empty(sk) &&
692 refcount_read(&sk->sk_wmem_alloc) > skb->truesize;
693}
694
695static void tcp_push(struct sock *sk, int flags, int mss_now,
696 int nonagle, int size_goal)
697{
698 struct tcp_sock *tp = tcp_sk(sk);
699 struct sk_buff *skb;
700
701 skb = tcp_write_queue_tail(sk);
702 if (!skb)
703 return;
704 if (!(flags & MSG_MORE) || forced_push(tp))
705 tcp_mark_push(tp, skb);
706
707 tcp_mark_urg(tp, flags);
708
709 if (tcp_should_autocork(sk, skb, size_goal)) {
710
711 /* avoid atomic op if TSQ_THROTTLED bit is already set */
712 if (!test_bit(TSQ_THROTTLED, &sk->sk_tsq_flags)) {
713 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
714 set_bit(TSQ_THROTTLED, &sk->sk_tsq_flags);
715 }
716 /* It is possible TX completion already happened
717 * before we set TSQ_THROTTLED.
718 */
719 if (refcount_read(&sk->sk_wmem_alloc) > skb->truesize)
720 return;
721 }
722
723 if (flags & MSG_MORE)
724 nonagle = TCP_NAGLE_CORK;
725
726 __tcp_push_pending_frames(sk, mss_now, nonagle);
727}
728
729static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
730 unsigned int offset, size_t len)
731{
732 struct tcp_splice_state *tss = rd_desc->arg.data;
733 int ret;
734
735 ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
736 min(rd_desc->count, len), tss->flags);
737 if (ret > 0)
738 rd_desc->count -= ret;
739 return ret;
740}
741
742static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
743{
744 /* Store TCP splice context information in read_descriptor_t. */
745 read_descriptor_t rd_desc = {
746 .arg.data = tss,
747 .count = tss->len,
748 };
749
750 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
751}
752
753/**
754 * tcp_splice_read - splice data from TCP socket to a pipe
755 * @sock: socket to splice from
756 * @ppos: position (not valid)
757 * @pipe: pipe to splice to
758 * @len: number of bytes to splice
759 * @flags: splice modifier flags
760 *
761 * Description:
762 * Will read pages from given socket and fill them into a pipe.
763 *
764 **/
765ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
766 struct pipe_inode_info *pipe, size_t len,
767 unsigned int flags)
768{
769 struct sock *sk = sock->sk;
770 struct tcp_splice_state tss = {
771 .pipe = pipe,
772 .len = len,
773 .flags = flags,
774 };
775 long timeo;
776 ssize_t spliced;
777 int ret;
778
779 sock_rps_record_flow(sk);
780 /*
781 * We can't seek on a socket input
782 */
783 if (unlikely(*ppos))
784 return -ESPIPE;
785
786 ret = spliced = 0;
787
788 lock_sock(sk);
789
790 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
791 while (tss.len) {
792 ret = __tcp_splice_read(sk, &tss);
793 if (ret < 0)
794 break;
795 else if (!ret) {
796 if (spliced)
797 break;
798 if (sock_flag(sk, SOCK_DONE))
799 break;
800 if (sk->sk_err) {
801 ret = sock_error(sk);
802 break;
803 }
804 if (sk->sk_shutdown & RCV_SHUTDOWN)
805 break;
806 if (sk->sk_state == TCP_CLOSE) {
807 /*
808 * This occurs when user tries to read
809 * from never connected socket.
810 */
811 ret = -ENOTCONN;
812 break;
813 }
814 if (!timeo) {
815 ret = -EAGAIN;
816 break;
817 }
818 /* if __tcp_splice_read() got nothing while we have
819 * an skb in receive queue, we do not want to loop.
820 * This might happen with URG data.
821 */
822 if (!skb_queue_empty(&sk->sk_receive_queue))
823 break;
824 sk_wait_data(sk, &timeo, NULL);
825 if (signal_pending(current)) {
826 ret = sock_intr_errno(timeo);
827 break;
828 }
829 continue;
830 }
831 tss.len -= ret;
832 spliced += ret;
833
834 if (!timeo)
835 break;
836 release_sock(sk);
837 lock_sock(sk);
838
839 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
840 (sk->sk_shutdown & RCV_SHUTDOWN) ||
841 signal_pending(current))
842 break;
843 }
844
845 release_sock(sk);
846
847 if (spliced)
848 return spliced;
849
850 return ret;
851}
852EXPORT_SYMBOL(tcp_splice_read);
853
854struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
855 bool force_schedule)
856{
857 struct sk_buff *skb;
858
859 if (likely(!size)) {
860 skb = sk->sk_tx_skb_cache;
861 if (skb) {
862 skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
863 sk->sk_tx_skb_cache = NULL;
864 pskb_trim(skb, 0);
865 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
866 skb_shinfo(skb)->tx_flags = 0;
867 memset(TCP_SKB_CB(skb), 0, sizeof(struct tcp_skb_cb));
868 return skb;
869 }
870 }
871 /* The TCP header must be at least 32-bit aligned. */
872 size = ALIGN(size, 4);
873
874 if (unlikely(tcp_under_memory_pressure(sk)))
875 sk_mem_reclaim_partial(sk);
876
877 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
878 if (likely(skb)) {
879 bool mem_scheduled;
880
881 if (force_schedule) {
882 mem_scheduled = true;
883 sk_forced_mem_schedule(sk, skb->truesize);
884 } else {
885 mem_scheduled = sk_wmem_schedule(sk, skb->truesize);
886 }
887 if (likely(mem_scheduled)) {
888 skb_reserve(skb, sk->sk_prot->max_header);
889 /*
890 * Make sure that we have exactly size bytes
891 * available to the caller, no more, no less.
892 */
893 skb->reserved_tailroom = skb->end - skb->tail - size;
894 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
895 return skb;
896 }
897 __kfree_skb(skb);
898 } else {
899 sk->sk_prot->enter_memory_pressure(sk);
900 sk_stream_moderate_sndbuf(sk);
901 }
902 return NULL;
903}
904
905static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
906 int large_allowed)
907{
908 struct tcp_sock *tp = tcp_sk(sk);
909 u32 new_size_goal, size_goal;
910
911 if (!large_allowed)
912 return mss_now;
913
914 /* Note : tcp_tso_autosize() will eventually split this later */
915 new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER;
916 new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);
917
918 /* We try hard to avoid divides here */
919 size_goal = tp->gso_segs * mss_now;
920 if (unlikely(new_size_goal < size_goal ||
921 new_size_goal >= size_goal + mss_now)) {
922 tp->gso_segs = min_t(u16, new_size_goal / mss_now,
923 sk->sk_gso_max_segs);
924 size_goal = tp->gso_segs * mss_now;
925 }
926
927 return max(size_goal, mss_now);
928}
929
930static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
931{
932 int mss_now;
933
934 mss_now = tcp_current_mss(sk);
935 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
936
937 return mss_now;
938}
939
940/* In some cases, both sendpage() and sendmsg() could have added
941 * an skb to the write queue, but failed adding payload on it.
942 * We need to remove it to consume less memory, but more
943 * importantly be able to generate EPOLLOUT for Edge Trigger epoll()
944 * users.
945 */
946static void tcp_remove_empty_skb(struct sock *sk, struct sk_buff *skb)
947{
948 if (skb && !skb->len) {
949 tcp_unlink_write_queue(skb, sk);
950 if (tcp_write_queue_empty(sk))
951 tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
952 sk_wmem_free_skb(sk, skb);
953 }
954}
955
956ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
957 size_t size, int flags)
958{
959 struct tcp_sock *tp = tcp_sk(sk);
960 int mss_now, size_goal;
961 int err;
962 ssize_t copied;
963 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
964
965 if (IS_ENABLED(CONFIG_DEBUG_VM) &&
966 WARN_ONCE(PageSlab(page), "page must not be a Slab one"))
967 return -EINVAL;
968
969 /* Wait for a connection to finish. One exception is TCP Fast Open
970 * (passive side) where data is allowed to be sent before a connection
971 * is fully established.
972 */
973 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
974 !tcp_passive_fastopen(sk)) {
975 err = sk_stream_wait_connect(sk, &timeo);
976 if (err != 0)
977 goto out_err;
978 }
979
980 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
981
982 mss_now = tcp_send_mss(sk, &size_goal, flags);
983 copied = 0;
984
985 err = -EPIPE;
986 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
987 goto out_err;
988
989 while (size > 0) {
990 struct sk_buff *skb = tcp_write_queue_tail(sk);
991 int copy, i;
992 bool can_coalesce;
993
994 if (!skb || (copy = size_goal - skb->len) <= 0 ||
995 !tcp_skb_can_collapse_to(skb)) {
996new_segment:
997 if (!sk_stream_memory_free(sk))
998 goto wait_for_sndbuf;
999
1000 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
1001 tcp_rtx_and_write_queues_empty(sk));
1002 if (!skb)
1003 goto wait_for_memory;
1004
1005#ifdef CONFIG_TLS_DEVICE
1006 skb->decrypted = !!(flags & MSG_SENDPAGE_DECRYPTED);
1007#endif
1008 skb_entail(sk, skb);
1009 copy = size_goal;
1010 }
1011
1012 if (copy > size)
1013 copy = size;
1014
1015 i = skb_shinfo(skb)->nr_frags;
1016 can_coalesce = skb_can_coalesce(skb, i, page, offset);
1017 if (!can_coalesce && i >= sysctl_max_skb_frags) {
1018 tcp_mark_push(tp, skb);
1019 goto new_segment;
1020 }
1021 if (!sk_wmem_schedule(sk, copy))
1022 goto wait_for_memory;
1023
1024 if (can_coalesce) {
1025 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1026 } else {
1027 get_page(page);
1028 skb_fill_page_desc(skb, i, page, offset, copy);
1029 }
1030
1031 if (!(flags & MSG_NO_SHARED_FRAGS))
1032 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1033
1034 skb->len += copy;
1035 skb->data_len += copy;
1036 skb->truesize += copy;
1037 sk_wmem_queued_add(sk, copy);
1038 sk_mem_charge(sk, copy);
1039 skb->ip_summed = CHECKSUM_PARTIAL;
1040 WRITE_ONCE(tp->write_seq, tp->write_seq + copy);
1041 TCP_SKB_CB(skb)->end_seq += copy;
1042 tcp_skb_pcount_set(skb, 0);
1043
1044 if (!copied)
1045 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1046
1047 copied += copy;
1048 offset += copy;
1049 size -= copy;
1050 if (!size)
1051 goto out;
1052
1053 if (skb->len < size_goal || (flags & MSG_OOB))
1054 continue;
1055
1056 if (forced_push(tp)) {
1057 tcp_mark_push(tp, skb);
1058 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1059 } else if (skb == tcp_send_head(sk))
1060 tcp_push_one(sk, mss_now);
1061 continue;
1062
1063wait_for_sndbuf:
1064 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1065wait_for_memory:
1066 tcp_push(sk, flags & ~MSG_MORE, mss_now,
1067 TCP_NAGLE_PUSH, size_goal);
1068
1069 err = sk_stream_wait_memory(sk, &timeo);
1070 if (err != 0)
1071 goto do_error;
1072
1073 mss_now = tcp_send_mss(sk, &size_goal, flags);
1074 }
1075
1076out:
1077 if (copied) {
1078 tcp_tx_timestamp(sk, sk->sk_tsflags);
1079 if (!(flags & MSG_SENDPAGE_NOTLAST))
1080 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1081 }
1082 return copied;
1083
1084do_error:
1085 tcp_remove_empty_skb(sk, tcp_write_queue_tail(sk));
1086 if (copied)
1087 goto out;
1088out_err:
1089 /* make sure we wake any epoll edge trigger waiter */
1090 if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 &&
1091 err == -EAGAIN)) {
1092 sk->sk_write_space(sk);
1093 tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
1094 }
1095 return sk_stream_error(sk, flags, err);
1096}
1097EXPORT_SYMBOL_GPL(do_tcp_sendpages);
1098
1099int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset,
1100 size_t size, int flags)
1101{
1102 if (!(sk->sk_route_caps & NETIF_F_SG))
1103 return sock_no_sendpage_locked(sk, page, offset, size, flags);
1104
1105 tcp_rate_check_app_limited(sk); /* is sending application-limited? */
1106
1107 return do_tcp_sendpages(sk, page, offset, size, flags);
1108}
1109EXPORT_SYMBOL_GPL(tcp_sendpage_locked);
1110
1111int tcp_sendpage(struct sock *sk, struct page *page, int offset,
1112 size_t size, int flags)
1113{
1114 int ret;
1115
1116 lock_sock(sk);
1117 ret = tcp_sendpage_locked(sk, page, offset, size, flags);
1118 release_sock(sk);
1119
1120 return ret;
1121}
1122EXPORT_SYMBOL(tcp_sendpage);
1123
1124void tcp_free_fastopen_req(struct tcp_sock *tp)
1125{
1126 if (tp->fastopen_req) {
1127 kfree(tp->fastopen_req);
1128 tp->fastopen_req = NULL;
1129 }
1130}
1131
1132static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1133 int *copied, size_t size,
1134 struct ubuf_info *uarg)
1135{
1136 struct tcp_sock *tp = tcp_sk(sk);
1137 struct inet_sock *inet = inet_sk(sk);
1138 struct sockaddr *uaddr = msg->msg_name;
1139 int err, flags;
1140
1141 if (!(sock_net(sk)->ipv4.sysctl_tcp_fastopen & TFO_CLIENT_ENABLE) ||
1142 (uaddr && msg->msg_namelen >= sizeof(uaddr->sa_family) &&
1143 uaddr->sa_family == AF_UNSPEC))
1144 return -EOPNOTSUPP;
1145 if (tp->fastopen_req)
1146 return -EALREADY; /* Another Fast Open is in progress */
1147
1148 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1149 sk->sk_allocation);
1150 if (unlikely(!tp->fastopen_req))
1151 return -ENOBUFS;
1152 tp->fastopen_req->data = msg;
1153 tp->fastopen_req->size = size;
1154 tp->fastopen_req->uarg = uarg;
1155
1156 if (inet->defer_connect) {
1157 err = tcp_connect(sk);
1158 /* Same failure procedure as in tcp_v4/6_connect */
1159 if (err) {
1160 tcp_set_state(sk, TCP_CLOSE);
1161 inet->inet_dport = 0;
1162 sk->sk_route_caps = 0;
1163 }
1164 }
1165 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1166 err = __inet_stream_connect(sk->sk_socket, uaddr,
1167 msg->msg_namelen, flags, 1);
1168 /* fastopen_req could already be freed in __inet_stream_connect
1169 * if the connection times out or gets rst
1170 */
1171 if (tp->fastopen_req) {
1172 *copied = tp->fastopen_req->copied;
1173 tcp_free_fastopen_req(tp);
1174 inet->defer_connect = 0;
1175 }
1176 return err;
1177}
1178
1179int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
1180{
1181 struct tcp_sock *tp = tcp_sk(sk);
1182 struct ubuf_info *uarg = NULL;
1183 struct sk_buff *skb;
1184 struct sockcm_cookie sockc;
1185 int flags, err, copied = 0;
1186 int mss_now = 0, size_goal, copied_syn = 0;
1187 int process_backlog = 0;
1188 bool zc = false;
1189 long timeo;
1190
1191 flags = msg->msg_flags;
1192
1193 if (flags & MSG_ZEROCOPY && size && sock_flag(sk, SOCK_ZEROCOPY)) {
1194 skb = tcp_write_queue_tail(sk);
1195 uarg = sock_zerocopy_realloc(sk, size, skb_zcopy(skb));
1196 if (!uarg) {
1197 err = -ENOBUFS;
1198 goto out_err;
1199 }
1200
1201 zc = sk->sk_route_caps & NETIF_F_SG;
1202 if (!zc)
1203 uarg->zerocopy = 0;
1204 }
1205
1206 if (unlikely(flags & MSG_FASTOPEN || inet_sk(sk)->defer_connect) &&
1207 !tp->repair) {
1208 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size, uarg);
1209 if (err == -EINPROGRESS && copied_syn > 0)
1210 goto out;
1211 else if (err)
1212 goto out_err;
1213 }
1214
1215 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1216
1217 tcp_rate_check_app_limited(sk); /* is sending application-limited? */
1218
1219 /* Wait for a connection to finish. One exception is TCP Fast Open
1220 * (passive side) where data is allowed to be sent before a connection
1221 * is fully established.
1222 */
1223 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1224 !tcp_passive_fastopen(sk)) {
1225 err = sk_stream_wait_connect(sk, &timeo);
1226 if (err != 0)
1227 goto do_error;
1228 }
1229
1230 if (unlikely(tp->repair)) {
1231 if (tp->repair_queue == TCP_RECV_QUEUE) {
1232 copied = tcp_send_rcvq(sk, msg, size);
1233 goto out_nopush;
1234 }
1235
1236 err = -EINVAL;
1237 if (tp->repair_queue == TCP_NO_QUEUE)
1238 goto out_err;
1239
1240 /* 'common' sending to sendq */
1241 }
1242
1243 sockcm_init(&sockc, sk);
1244 if (msg->msg_controllen) {
1245 err = sock_cmsg_send(sk, msg, &sockc);
1246 if (unlikely(err)) {
1247 err = -EINVAL;
1248 goto out_err;
1249 }
1250 }
1251
1252 /* This should be in poll */
1253 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
1254
1255 /* Ok commence sending. */
1256 copied = 0;
1257
1258restart:
1259 mss_now = tcp_send_mss(sk, &size_goal, flags);
1260
1261 err = -EPIPE;
1262 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1263 goto do_error;
1264
1265 while (msg_data_left(msg)) {
1266 int copy = 0;
1267
1268 skb = tcp_write_queue_tail(sk);
1269 if (skb)
1270 copy = size_goal - skb->len;
1271
1272 if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) {
1273 bool first_skb;
1274
1275new_segment:
1276 if (!sk_stream_memory_free(sk))
1277 goto wait_for_sndbuf;
1278
1279 if (unlikely(process_backlog >= 16)) {
1280 process_backlog = 0;
1281 if (sk_flush_backlog(sk))
1282 goto restart;
1283 }
1284 first_skb = tcp_rtx_and_write_queues_empty(sk);
1285 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
1286 first_skb);
1287 if (!skb)
1288 goto wait_for_memory;
1289
1290 process_backlog++;
1291 skb->ip_summed = CHECKSUM_PARTIAL;
1292
1293 skb_entail(sk, skb);
1294 copy = size_goal;
1295
1296 /* All packets are restored as if they have
1297 * already been sent. skb_mstamp_ns isn't set to
1298 * avoid wrong rtt estimation.
1299 */
1300 if (tp->repair)
1301 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
1302 }
1303
1304 /* Try to append data to the end of skb. */
1305 if (copy > msg_data_left(msg))
1306 copy = msg_data_left(msg);
1307
1308 /* Where to copy to? */
1309 if (skb_availroom(skb) > 0 && !zc) {
1310 /* We have some space in skb head. Superb! */
1311 copy = min_t(int, copy, skb_availroom(skb));
1312 err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);
1313 if (err)
1314 goto do_fault;
1315 } else if (!zc) {
1316 bool merge = true;
1317 int i = skb_shinfo(skb)->nr_frags;
1318 struct page_frag *pfrag = sk_page_frag(sk);
1319
1320 if (!sk_page_frag_refill(sk, pfrag))
1321 goto wait_for_memory;
1322
1323 if (!skb_can_coalesce(skb, i, pfrag->page,
1324 pfrag->offset)) {
1325 if (i >= sysctl_max_skb_frags) {
1326 tcp_mark_push(tp, skb);
1327 goto new_segment;
1328 }
1329 merge = false;
1330 }
1331
1332 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1333
1334 if (!sk_wmem_schedule(sk, copy))
1335 goto wait_for_memory;
1336
1337 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
1338 pfrag->page,
1339 pfrag->offset,
1340 copy);
1341 if (err)
1342 goto do_error;
1343
1344 /* Update the skb. */
1345 if (merge) {
1346 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1347 } else {
1348 skb_fill_page_desc(skb, i, pfrag->page,
1349 pfrag->offset, copy);
1350 page_ref_inc(pfrag->page);
1351 }
1352 pfrag->offset += copy;
1353 } else {
1354 err = skb_zerocopy_iter_stream(sk, skb, msg, copy, uarg);
1355 if (err == -EMSGSIZE || err == -EEXIST) {
1356 tcp_mark_push(tp, skb);
1357 goto new_segment;
1358 }
1359 if (err < 0)
1360 goto do_error;
1361 copy = err;
1362 }
1363
1364 if (!copied)
1365 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1366
1367 WRITE_ONCE(tp->write_seq, tp->write_seq + copy);
1368 TCP_SKB_CB(skb)->end_seq += copy;
1369 tcp_skb_pcount_set(skb, 0);
1370
1371 copied += copy;
1372 if (!msg_data_left(msg)) {
1373 if (unlikely(flags & MSG_EOR))
1374 TCP_SKB_CB(skb)->eor = 1;
1375 goto out;
1376 }
1377
1378 if (skb->len < size_goal || (flags & MSG_OOB) || unlikely(tp->repair))
1379 continue;
1380
1381 if (forced_push(tp)) {
1382 tcp_mark_push(tp, skb);
1383 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1384 } else if (skb == tcp_send_head(sk))
1385 tcp_push_one(sk, mss_now);
1386 continue;
1387
1388wait_for_sndbuf:
1389 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1390wait_for_memory:
1391 if (copied)
1392 tcp_push(sk, flags & ~MSG_MORE, mss_now,
1393 TCP_NAGLE_PUSH, size_goal);
1394
1395 err = sk_stream_wait_memory(sk, &timeo);
1396 if (err != 0)
1397 goto do_error;
1398
1399 mss_now = tcp_send_mss(sk, &size_goal, flags);
1400 }
1401
1402out:
1403 if (copied) {
1404 tcp_tx_timestamp(sk, sockc.tsflags);
1405 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1406 }
1407out_nopush:
1408 sock_zerocopy_put(uarg);
1409 return copied + copied_syn;
1410
1411do_error:
1412 skb = tcp_write_queue_tail(sk);
1413do_fault:
1414 tcp_remove_empty_skb(sk, skb);
1415
1416 if (copied + copied_syn)
1417 goto out;
1418out_err:
1419 sock_zerocopy_put_abort(uarg, true);
1420 err = sk_stream_error(sk, flags, err);
1421 /* make sure we wake any epoll edge trigger waiter */
1422 if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 &&
1423 err == -EAGAIN)) {
1424 sk->sk_write_space(sk);
1425 tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
1426 }
1427 return err;
1428}
1429EXPORT_SYMBOL_GPL(tcp_sendmsg_locked);
1430
1431int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
1432{
1433 int ret;
1434
1435 lock_sock(sk);
1436 ret = tcp_sendmsg_locked(sk, msg, size);
1437 release_sock(sk);
1438
1439 return ret;
1440}
1441EXPORT_SYMBOL(tcp_sendmsg);
1442
1443/*
1444 * Handle reading urgent data. BSD has very simple semantics for
1445 * this, no blocking and very strange errors 8)
1446 */
1447
1448static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1449{
1450 struct tcp_sock *tp = tcp_sk(sk);
1451
1452 /* No URG data to read. */
1453 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1454 tp->urg_data == TCP_URG_READ)
1455 return -EINVAL; /* Yes this is right ! */
1456
1457 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1458 return -ENOTCONN;
1459
1460 if (tp->urg_data & TCP_URG_VALID) {
1461 int err = 0;
1462 char c = tp->urg_data;
1463
1464 if (!(flags & MSG_PEEK))
1465 tp->urg_data = TCP_URG_READ;
1466
1467 /* Read urgent data. */
1468 msg->msg_flags |= MSG_OOB;
1469
1470 if (len > 0) {
1471 if (!(flags & MSG_TRUNC))
1472 err = memcpy_to_msg(msg, &c, 1);
1473 len = 1;
1474 } else
1475 msg->msg_flags |= MSG_TRUNC;
1476
1477 return err ? -EFAULT : len;
1478 }
1479
1480 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1481 return 0;
1482
1483 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1484 * the available implementations agree in this case:
1485 * this call should never block, independent of the
1486 * blocking state of the socket.
1487 * Mike <pall@rz.uni-karlsruhe.de>
1488 */
1489 return -EAGAIN;
1490}
1491
1492static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1493{
1494 struct sk_buff *skb;
1495 int copied = 0, err = 0;
1496
1497 /* XXX -- need to support SO_PEEK_OFF */
1498
1499 skb_rbtree_walk(skb, &sk->tcp_rtx_queue) {
1500 err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
1501 if (err)
1502 return err;
1503 copied += skb->len;
1504 }
1505
1506 skb_queue_walk(&sk->sk_write_queue, skb) {
1507 err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
1508 if (err)
1509 break;
1510
1511 copied += skb->len;
1512 }
1513
1514 return err ?: copied;
1515}
1516
1517/* Clean up the receive buffer for full frames taken by the user,
1518 * then send an ACK if necessary. COPIED is the number of bytes
1519 * tcp_recvmsg has given to the user so far, it speeds up the
1520 * calculation of whether or not we must ACK for the sake of
1521 * a window update.
1522 */
1523static void tcp_cleanup_rbuf(struct sock *sk, int copied)
1524{
1525 struct tcp_sock *tp = tcp_sk(sk);
1526 bool time_to_ack = false;
1527
1528 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1529
1530 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1531 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1532 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1533
1534 if (inet_csk_ack_scheduled(sk)) {
1535 const struct inet_connection_sock *icsk = inet_csk(sk);
1536 /* Delayed ACKs frequently hit locked sockets during bulk
1537 * receive. */
1538 if (icsk->icsk_ack.blocked ||
1539 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1540 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1541 /*
1542 * If this read emptied read buffer, we send ACK, if
1543 * connection is not bidirectional, user drained
1544 * receive buffer and there was a small segment
1545 * in queue.
1546 */
1547 (copied > 0 &&
1548 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1549 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1550 !inet_csk_in_pingpong_mode(sk))) &&
1551 !atomic_read(&sk->sk_rmem_alloc)))
1552 time_to_ack = true;
1553 }
1554
1555 /* We send an ACK if we can now advertise a non-zero window
1556 * which has been raised "significantly".
1557 *
1558 * Even if window raised up to infinity, do not send window open ACK
1559 * in states, where we will not receive more. It is useless.
1560 */
1561 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1562 __u32 rcv_window_now = tcp_receive_window(tp);
1563
1564 /* Optimize, __tcp_select_window() is not cheap. */
1565 if (2*rcv_window_now <= tp->window_clamp) {
1566 __u32 new_window = __tcp_select_window(sk);
1567
1568 /* Send ACK now, if this read freed lots of space
1569 * in our buffer. Certainly, new_window is new window.
1570 * We can advertise it now, if it is not less than current one.
1571 * "Lots" means "at least twice" here.
1572 */
1573 if (new_window && new_window >= 2 * rcv_window_now)
1574 time_to_ack = true;
1575 }
1576 }
1577 if (time_to_ack)
1578 tcp_send_ack(sk);
1579}
1580
1581static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1582{
1583 struct sk_buff *skb;
1584 u32 offset;
1585
1586 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1587 offset = seq - TCP_SKB_CB(skb)->seq;
1588 if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
1589 pr_err_once("%s: found a SYN, please report !\n", __func__);
1590 offset--;
1591 }
1592 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
1593 *off = offset;
1594 return skb;
1595 }
1596 /* This looks weird, but this can happen if TCP collapsing
1597 * splitted a fat GRO packet, while we released socket lock
1598 * in skb_splice_bits()
1599 */
1600 sk_eat_skb(sk, skb);
1601 }
1602 return NULL;
1603}
1604
1605/*
1606 * This routine provides an alternative to tcp_recvmsg() for routines
1607 * that would like to handle copying from skbuffs directly in 'sendfile'
1608 * fashion.
1609 * Note:
1610 * - It is assumed that the socket was locked by the caller.
1611 * - The routine does not block.
1612 * - At present, there is no support for reading OOB data
1613 * or for 'peeking' the socket using this routine
1614 * (although both would be easy to implement).
1615 */
1616int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1617 sk_read_actor_t recv_actor)
1618{
1619 struct sk_buff *skb;
1620 struct tcp_sock *tp = tcp_sk(sk);
1621 u32 seq = tp->copied_seq;
1622 u32 offset;
1623 int copied = 0;
1624
1625 if (sk->sk_state == TCP_LISTEN)
1626 return -ENOTCONN;
1627 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1628 if (offset < skb->len) {
1629 int used;
1630 size_t len;
1631
1632 len = skb->len - offset;
1633 /* Stop reading if we hit a patch of urgent data */
1634 if (tp->urg_data) {
1635 u32 urg_offset = tp->urg_seq - seq;
1636 if (urg_offset < len)
1637 len = urg_offset;
1638 if (!len)
1639 break;
1640 }
1641 used = recv_actor(desc, skb, offset, len);
1642 if (used <= 0) {
1643 if (!copied)
1644 copied = used;
1645 break;
1646 } else if (used <= len) {
1647 seq += used;
1648 copied += used;
1649 offset += used;
1650 }
1651 /* If recv_actor drops the lock (e.g. TCP splice
1652 * receive) the skb pointer might be invalid when
1653 * getting here: tcp_collapse might have deleted it
1654 * while aggregating skbs from the socket queue.
1655 */
1656 skb = tcp_recv_skb(sk, seq - 1, &offset);
1657 if (!skb)
1658 break;
1659 /* TCP coalescing might have appended data to the skb.
1660 * Try to splice more frags
1661 */
1662 if (offset + 1 != skb->len)
1663 continue;
1664 }
1665 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1666 sk_eat_skb(sk, skb);
1667 ++seq;
1668 break;
1669 }
1670 sk_eat_skb(sk, skb);
1671 if (!desc->count)
1672 break;
1673 WRITE_ONCE(tp->copied_seq, seq);
1674 }
1675 WRITE_ONCE(tp->copied_seq, seq);
1676
1677 tcp_rcv_space_adjust(sk);
1678
1679 /* Clean up data we have read: This will do ACK frames. */
1680 if (copied > 0) {
1681 tcp_recv_skb(sk, seq, &offset);
1682 tcp_cleanup_rbuf(sk, copied);
1683 }
1684 return copied;
1685}
1686EXPORT_SYMBOL(tcp_read_sock);
1687
1688int tcp_peek_len(struct socket *sock)
1689{
1690 return tcp_inq(sock->sk);
1691}
1692EXPORT_SYMBOL(tcp_peek_len);
1693
1694/* Make sure sk_rcvbuf is big enough to satisfy SO_RCVLOWAT hint */
1695int tcp_set_rcvlowat(struct sock *sk, int val)
1696{
1697 int cap;
1698
1699 if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
1700 cap = sk->sk_rcvbuf >> 1;
1701 else
1702 cap = sock_net(sk)->ipv4.sysctl_tcp_rmem[2] >> 1;
1703 val = min(val, cap);
1704 WRITE_ONCE(sk->sk_rcvlowat, val ? : 1);
1705
1706 /* Check if we need to signal EPOLLIN right now */
1707 tcp_data_ready(sk);
1708
1709 if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
1710 return 0;
1711
1712 val <<= 1;
1713 if (val > sk->sk_rcvbuf) {
1714 WRITE_ONCE(sk->sk_rcvbuf, val);
1715 tcp_sk(sk)->window_clamp = tcp_win_from_space(sk, val);
1716 }
1717 return 0;
1718}
1719EXPORT_SYMBOL(tcp_set_rcvlowat);
1720
1721#ifdef CONFIG_MMU
1722static const struct vm_operations_struct tcp_vm_ops = {
1723};
1724
1725int tcp_mmap(struct file *file, struct socket *sock,
1726 struct vm_area_struct *vma)
1727{
1728 if (vma->vm_flags & (VM_WRITE | VM_EXEC))
1729 return -EPERM;
1730 vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
1731
1732 /* Instruct vm_insert_page() to not down_read(mmap_sem) */
1733 vma->vm_flags |= VM_MIXEDMAP;
1734
1735 vma->vm_ops = &tcp_vm_ops;
1736 return 0;
1737}
1738EXPORT_SYMBOL(tcp_mmap);
1739
1740static int tcp_zerocopy_receive(struct sock *sk,
1741 struct tcp_zerocopy_receive *zc)
1742{
1743 unsigned long address = (unsigned long)zc->address;
1744 const skb_frag_t *frags = NULL;
1745 u32 length = 0, seq, offset;
1746 struct vm_area_struct *vma;
1747 struct sk_buff *skb = NULL;
1748 struct tcp_sock *tp;
1749 int inq;
1750 int ret;
1751
1752 if (address & (PAGE_SIZE - 1) || address != zc->address)
1753 return -EINVAL;
1754
1755 if (sk->sk_state == TCP_LISTEN)
1756 return -ENOTCONN;
1757
1758 sock_rps_record_flow(sk);
1759
1760 down_read(¤t->mm->mmap_sem);
1761
1762 ret = -EINVAL;
1763 vma = find_vma(current->mm, address);
1764 if (!vma || vma->vm_start > address || vma->vm_ops != &tcp_vm_ops)
1765 goto out;
1766 zc->length = min_t(unsigned long, zc->length, vma->vm_end - address);
1767
1768 tp = tcp_sk(sk);
1769 seq = tp->copied_seq;
1770 inq = tcp_inq(sk);
1771 zc->length = min_t(u32, zc->length, inq);
1772 zc->length &= ~(PAGE_SIZE - 1);
1773 if (zc->length) {
1774 zap_page_range(vma, address, zc->length);
1775 zc->recv_skip_hint = 0;
1776 } else {
1777 zc->recv_skip_hint = inq;
1778 }
1779 ret = 0;
1780 while (length + PAGE_SIZE <= zc->length) {
1781 if (zc->recv_skip_hint < PAGE_SIZE) {
1782 if (skb) {
1783 skb = skb->next;
1784 offset = seq - TCP_SKB_CB(skb)->seq;
1785 } else {
1786 skb = tcp_recv_skb(sk, seq, &offset);
1787 }
1788
1789 zc->recv_skip_hint = skb->len - offset;
1790 offset -= skb_headlen(skb);
1791 if ((int)offset < 0 || skb_has_frag_list(skb))
1792 break;
1793 frags = skb_shinfo(skb)->frags;
1794 while (offset) {
1795 if (skb_frag_size(frags) > offset)
1796 goto out;
1797 offset -= skb_frag_size(frags);
1798 frags++;
1799 }
1800 }
1801 if (skb_frag_size(frags) != PAGE_SIZE || skb_frag_off(frags)) {
1802 int remaining = zc->recv_skip_hint;
1803
1804 while (remaining && (skb_frag_size(frags) != PAGE_SIZE ||
1805 skb_frag_off(frags))) {
1806 remaining -= skb_frag_size(frags);
1807 frags++;
1808 }
1809 zc->recv_skip_hint -= remaining;
1810 break;
1811 }
1812 ret = vm_insert_page(vma, address + length,
1813 skb_frag_page(frags));
1814 if (ret)
1815 break;
1816 length += PAGE_SIZE;
1817 seq += PAGE_SIZE;
1818 zc->recv_skip_hint -= PAGE_SIZE;
1819 frags++;
1820 }
1821out:
1822 up_read(¤t->mm->mmap_sem);
1823 if (length) {
1824 WRITE_ONCE(tp->copied_seq, seq);
1825 tcp_rcv_space_adjust(sk);
1826
1827 /* Clean up data we have read: This will do ACK frames. */
1828 tcp_recv_skb(sk, seq, &offset);
1829 tcp_cleanup_rbuf(sk, length);
1830 ret = 0;
1831 if (length == zc->length)
1832 zc->recv_skip_hint = 0;
1833 } else {
1834 if (!zc->recv_skip_hint && sock_flag(sk, SOCK_DONE))
1835 ret = -EIO;
1836 }
1837 zc->length = length;
1838 return ret;
1839}
1840#endif
1841
1842static void tcp_update_recv_tstamps(struct sk_buff *skb,
1843 struct scm_timestamping_internal *tss)
1844{
1845 if (skb->tstamp)
1846 tss->ts[0] = ktime_to_timespec64(skb->tstamp);
1847 else
1848 tss->ts[0] = (struct timespec64) {0};
1849
1850 if (skb_hwtstamps(skb)->hwtstamp)
1851 tss->ts[2] = ktime_to_timespec64(skb_hwtstamps(skb)->hwtstamp);
1852 else
1853 tss->ts[2] = (struct timespec64) {0};
1854}
1855
1856/* Similar to __sock_recv_timestamp, but does not require an skb */
1857static void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
1858 struct scm_timestamping_internal *tss)
1859{
1860 int new_tstamp = sock_flag(sk, SOCK_TSTAMP_NEW);
1861 bool has_timestamping = false;
1862
1863 if (tss->ts[0].tv_sec || tss->ts[0].tv_nsec) {
1864 if (sock_flag(sk, SOCK_RCVTSTAMP)) {
1865 if (sock_flag(sk, SOCK_RCVTSTAMPNS)) {
1866 if (new_tstamp) {
1867 struct __kernel_timespec kts = {tss->ts[0].tv_sec, tss->ts[0].tv_nsec};
1868
1869 put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPNS_NEW,
1870 sizeof(kts), &kts);
1871 } else {
1872 struct timespec ts_old = timespec64_to_timespec(tss->ts[0]);
1873
1874 put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPNS_OLD,
1875 sizeof(ts_old), &ts_old);
1876 }
1877 } else {
1878 if (new_tstamp) {
1879 struct __kernel_sock_timeval stv;
1880
1881 stv.tv_sec = tss->ts[0].tv_sec;
1882 stv.tv_usec = tss->ts[0].tv_nsec / 1000;
1883 put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_NEW,
1884 sizeof(stv), &stv);
1885 } else {
1886 struct __kernel_old_timeval tv;
1887
1888 tv.tv_sec = tss->ts[0].tv_sec;
1889 tv.tv_usec = tss->ts[0].tv_nsec / 1000;
1890 put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_OLD,
1891 sizeof(tv), &tv);
1892 }
1893 }
1894 }
1895
1896 if (sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE)
1897 has_timestamping = true;
1898 else
1899 tss->ts[0] = (struct timespec64) {0};
1900 }
1901
1902 if (tss->ts[2].tv_sec || tss->ts[2].tv_nsec) {
1903 if (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)
1904 has_timestamping = true;
1905 else
1906 tss->ts[2] = (struct timespec64) {0};
1907 }
1908
1909 if (has_timestamping) {
1910 tss->ts[1] = (struct timespec64) {0};
1911 if (sock_flag(sk, SOCK_TSTAMP_NEW))
1912 put_cmsg_scm_timestamping64(msg, tss);
1913 else
1914 put_cmsg_scm_timestamping(msg, tss);
1915 }
1916}
1917
1918static int tcp_inq_hint(struct sock *sk)
1919{
1920 const struct tcp_sock *tp = tcp_sk(sk);
1921 u32 copied_seq = READ_ONCE(tp->copied_seq);
1922 u32 rcv_nxt = READ_ONCE(tp->rcv_nxt);
1923 int inq;
1924
1925 inq = rcv_nxt - copied_seq;
1926 if (unlikely(inq < 0 || copied_seq != READ_ONCE(tp->copied_seq))) {
1927 lock_sock(sk);
1928 inq = tp->rcv_nxt - tp->copied_seq;
1929 release_sock(sk);
1930 }
1931 /* After receiving a FIN, tell the user-space to continue reading
1932 * by returning a non-zero inq.
1933 */
1934 if (inq == 0 && sock_flag(sk, SOCK_DONE))
1935 inq = 1;
1936 return inq;
1937}
1938
1939/*
1940 * This routine copies from a sock struct into the user buffer.
1941 *
1942 * Technical note: in 2.3 we work on _locked_ socket, so that
1943 * tricks with *seq access order and skb->users are not required.
1944 * Probably, code can be easily improved even more.
1945 */
1946
1947int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
1948 int flags, int *addr_len)
1949{
1950 struct tcp_sock *tp = tcp_sk(sk);
1951 int copied = 0;
1952 u32 peek_seq;
1953 u32 *seq;
1954 unsigned long used;
1955 int err, inq;
1956 int target; /* Read at least this many bytes */
1957 long timeo;
1958 struct sk_buff *skb, *last;
1959 u32 urg_hole = 0;
1960 struct scm_timestamping_internal tss;
1961 bool has_tss = false;
1962 bool has_cmsg;
1963
1964 if (unlikely(flags & MSG_ERRQUEUE))
1965 return inet_recv_error(sk, msg, len, addr_len);
1966
1967 if (sk_can_busy_loop(sk) && skb_queue_empty_lockless(&sk->sk_receive_queue) &&
1968 (sk->sk_state == TCP_ESTABLISHED))
1969 sk_busy_loop(sk, nonblock);
1970
1971 lock_sock(sk);
1972
1973 err = -ENOTCONN;
1974 if (sk->sk_state == TCP_LISTEN)
1975 goto out;
1976
1977 has_cmsg = tp->recvmsg_inq;
1978 timeo = sock_rcvtimeo(sk, nonblock);
1979
1980 /* Urgent data needs to be handled specially. */
1981 if (flags & MSG_OOB)
1982 goto recv_urg;
1983
1984 if (unlikely(tp->repair)) {
1985 err = -EPERM;
1986 if (!(flags & MSG_PEEK))
1987 goto out;
1988
1989 if (tp->repair_queue == TCP_SEND_QUEUE)
1990 goto recv_sndq;
1991
1992 err = -EINVAL;
1993 if (tp->repair_queue == TCP_NO_QUEUE)
1994 goto out;
1995
1996 /* 'common' recv queue MSG_PEEK-ing */
1997 }
1998
1999 seq = &tp->copied_seq;
2000 if (flags & MSG_PEEK) {
2001 peek_seq = tp->copied_seq;
2002 seq = &peek_seq;
2003 }
2004
2005 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
2006
2007 do {
2008 u32 offset;
2009
2010 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
2011 if (tp->urg_data && tp->urg_seq == *seq) {
2012 if (copied)
2013 break;
2014 if (signal_pending(current)) {
2015 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
2016 break;
2017 }
2018 }
2019
2020 /* Next get a buffer. */
2021
2022 last = skb_peek_tail(&sk->sk_receive_queue);
2023 skb_queue_walk(&sk->sk_receive_queue, skb) {
2024 last = skb;
2025 /* Now that we have two receive queues this
2026 * shouldn't happen.
2027 */
2028 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
2029 "TCP recvmsg seq # bug: copied %X, seq %X, rcvnxt %X, fl %X\n",
2030 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
2031 flags))
2032 break;
2033
2034 offset = *seq - TCP_SKB_CB(skb)->seq;
2035 if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
2036 pr_err_once("%s: found a SYN, please report !\n", __func__);
2037 offset--;
2038 }
2039 if (offset < skb->len)
2040 goto found_ok_skb;
2041 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2042 goto found_fin_ok;
2043 WARN(!(flags & MSG_PEEK),
2044 "TCP recvmsg seq # bug 2: copied %X, seq %X, rcvnxt %X, fl %X\n",
2045 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
2046 }
2047
2048 /* Well, if we have backlog, try to process it now yet. */
2049
2050 if (copied >= target && !sk->sk_backlog.tail)
2051 break;
2052
2053 if (copied) {
2054 if (sk->sk_err ||
2055 sk->sk_state == TCP_CLOSE ||
2056 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2057 !timeo ||
2058 signal_pending(current))
2059 break;
2060 } else {
2061 if (sock_flag(sk, SOCK_DONE))
2062 break;
2063
2064 if (sk->sk_err) {
2065 copied = sock_error(sk);
2066 break;
2067 }
2068
2069 if (sk->sk_shutdown & RCV_SHUTDOWN)
2070 break;
2071
2072 if (sk->sk_state == TCP_CLOSE) {
2073 /* This occurs when user tries to read
2074 * from never connected socket.
2075 */
2076 copied = -ENOTCONN;
2077 break;
2078 }
2079
2080 if (!timeo) {
2081 copied = -EAGAIN;
2082 break;
2083 }
2084
2085 if (signal_pending(current)) {
2086 copied = sock_intr_errno(timeo);
2087 break;
2088 }
2089 }
2090
2091 tcp_cleanup_rbuf(sk, copied);
2092
2093 if (copied >= target) {
2094 /* Do not sleep, just process backlog. */
2095 release_sock(sk);
2096 lock_sock(sk);
2097 } else {
2098 sk_wait_data(sk, &timeo, last);
2099 }
2100
2101 if ((flags & MSG_PEEK) &&
2102 (peek_seq - copied - urg_hole != tp->copied_seq)) {
2103 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
2104 current->comm,
2105 task_pid_nr(current));
2106 peek_seq = tp->copied_seq;
2107 }
2108 continue;
2109
2110found_ok_skb:
2111 /* Ok so how much can we use? */
2112 used = skb->len - offset;
2113 if (len < used)
2114 used = len;
2115
2116 /* Do we have urgent data here? */
2117 if (tp->urg_data) {
2118 u32 urg_offset = tp->urg_seq - *seq;
2119 if (urg_offset < used) {
2120 if (!urg_offset) {
2121 if (!sock_flag(sk, SOCK_URGINLINE)) {
2122 WRITE_ONCE(*seq, *seq + 1);
2123 urg_hole++;
2124 offset++;
2125 used--;
2126 if (!used)
2127 goto skip_copy;
2128 }
2129 } else
2130 used = urg_offset;
2131 }
2132 }
2133
2134 if (!(flags & MSG_TRUNC)) {
2135 err = skb_copy_datagram_msg(skb, offset, msg, used);
2136 if (err) {
2137 /* Exception. Bailout! */
2138 if (!copied)
2139 copied = -EFAULT;
2140 break;
2141 }
2142 }
2143
2144 WRITE_ONCE(*seq, *seq + used);
2145 copied += used;
2146 len -= used;
2147
2148 tcp_rcv_space_adjust(sk);
2149
2150skip_copy:
2151 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
2152 tp->urg_data = 0;
2153 tcp_fast_path_check(sk);
2154 }
2155 if (used + offset < skb->len)
2156 continue;
2157
2158 if (TCP_SKB_CB(skb)->has_rxtstamp) {
2159 tcp_update_recv_tstamps(skb, &tss);
2160 has_tss = true;
2161 has_cmsg = true;
2162 }
2163 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2164 goto found_fin_ok;
2165 if (!(flags & MSG_PEEK))
2166 sk_eat_skb(sk, skb);
2167 continue;
2168
2169found_fin_ok:
2170 /* Process the FIN. */
2171 WRITE_ONCE(*seq, *seq + 1);
2172 if (!(flags & MSG_PEEK))
2173 sk_eat_skb(sk, skb);
2174 break;
2175 } while (len > 0);
2176
2177 /* According to UNIX98, msg_name/msg_namelen are ignored
2178 * on connected socket. I was just happy when found this 8) --ANK
2179 */
2180
2181 /* Clean up data we have read: This will do ACK frames. */
2182 tcp_cleanup_rbuf(sk, copied);
2183
2184 release_sock(sk);
2185
2186 if (has_cmsg) {
2187 if (has_tss)
2188 tcp_recv_timestamp(msg, sk, &tss);
2189 if (tp->recvmsg_inq) {
2190 inq = tcp_inq_hint(sk);
2191 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
2192 }
2193 }
2194
2195 return copied;
2196
2197out:
2198 release_sock(sk);
2199 return err;
2200
2201recv_urg:
2202 err = tcp_recv_urg(sk, msg, len, flags);
2203 goto out;
2204
2205recv_sndq:
2206 err = tcp_peek_sndq(sk, msg, len);
2207 goto out;
2208}
2209EXPORT_SYMBOL(tcp_recvmsg);
2210
2211void tcp_set_state(struct sock *sk, int state)
2212{
2213 int oldstate = sk->sk_state;
2214
2215 /* We defined a new enum for TCP states that are exported in BPF
2216 * so as not force the internal TCP states to be frozen. The
2217 * following checks will detect if an internal state value ever
2218 * differs from the BPF value. If this ever happens, then we will
2219 * need to remap the internal value to the BPF value before calling
2220 * tcp_call_bpf_2arg.
2221 */
2222 BUILD_BUG_ON((int)BPF_TCP_ESTABLISHED != (int)TCP_ESTABLISHED);
2223 BUILD_BUG_ON((int)BPF_TCP_SYN_SENT != (int)TCP_SYN_SENT);
2224 BUILD_BUG_ON((int)BPF_TCP_SYN_RECV != (int)TCP_SYN_RECV);
2225 BUILD_BUG_ON((int)BPF_TCP_FIN_WAIT1 != (int)TCP_FIN_WAIT1);
2226 BUILD_BUG_ON((int)BPF_TCP_FIN_WAIT2 != (int)TCP_FIN_WAIT2);
2227 BUILD_BUG_ON((int)BPF_TCP_TIME_WAIT != (int)TCP_TIME_WAIT);
2228 BUILD_BUG_ON((int)BPF_TCP_CLOSE != (int)TCP_CLOSE);
2229 BUILD_BUG_ON((int)BPF_TCP_CLOSE_WAIT != (int)TCP_CLOSE_WAIT);
2230 BUILD_BUG_ON((int)BPF_TCP_LAST_ACK != (int)TCP_LAST_ACK);
2231 BUILD_BUG_ON((int)BPF_TCP_LISTEN != (int)TCP_LISTEN);
2232 BUILD_BUG_ON((int)BPF_TCP_CLOSING != (int)TCP_CLOSING);
2233 BUILD_BUG_ON((int)BPF_TCP_NEW_SYN_RECV != (int)TCP_NEW_SYN_RECV);
2234 BUILD_BUG_ON((int)BPF_TCP_MAX_STATES != (int)TCP_MAX_STATES);
2235
2236 if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_STATE_CB_FLAG))
2237 tcp_call_bpf_2arg(sk, BPF_SOCK_OPS_STATE_CB, oldstate, state);
2238
2239 switch (state) {
2240 case TCP_ESTABLISHED:
2241 if (oldstate != TCP_ESTABLISHED)
2242 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
2243 break;
2244
2245 case TCP_CLOSE:
2246 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
2247 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
2248
2249 sk->sk_prot->unhash(sk);
2250 if (inet_csk(sk)->icsk_bind_hash &&
2251 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
2252 inet_put_port(sk);
2253 /* fall through */
2254 default:
2255 if (oldstate == TCP_ESTABLISHED)
2256 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
2257 }
2258
2259 /* Change state AFTER socket is unhashed to avoid closed
2260 * socket sitting in hash tables.
2261 */
2262 inet_sk_state_store(sk, state);
2263}
2264EXPORT_SYMBOL_GPL(tcp_set_state);
2265
2266/*
2267 * State processing on a close. This implements the state shift for
2268 * sending our FIN frame. Note that we only send a FIN for some
2269 * states. A shutdown() may have already sent the FIN, or we may be
2270 * closed.
2271 */
2272
2273static const unsigned char new_state[16] = {
2274 /* current state: new state: action: */
2275 [0 /* (Invalid) */] = TCP_CLOSE,
2276 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2277 [TCP_SYN_SENT] = TCP_CLOSE,
2278 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2279 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2280 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2281 [TCP_TIME_WAIT] = TCP_CLOSE,
2282 [TCP_CLOSE] = TCP_CLOSE,
2283 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2284 [TCP_LAST_ACK] = TCP_LAST_ACK,
2285 [TCP_LISTEN] = TCP_CLOSE,
2286 [TCP_CLOSING] = TCP_CLOSING,
2287 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2288};
2289
2290static int tcp_close_state(struct sock *sk)
2291{
2292 int next = (int)new_state[sk->sk_state];
2293 int ns = next & TCP_STATE_MASK;
2294
2295 tcp_set_state(sk, ns);
2296
2297 return next & TCP_ACTION_FIN;
2298}
2299
2300/*
2301 * Shutdown the sending side of a connection. Much like close except
2302 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
2303 */
2304
2305void tcp_shutdown(struct sock *sk, int how)
2306{
2307 /* We need to grab some memory, and put together a FIN,
2308 * and then put it into the queue to be sent.
2309 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
2310 */
2311 if (!(how & SEND_SHUTDOWN))
2312 return;
2313
2314 /* If we've already sent a FIN, or it's a closed state, skip this. */
2315 if ((1 << sk->sk_state) &
2316 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
2317 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
2318 /* Clear out any half completed packets. FIN if needed. */
2319 if (tcp_close_state(sk))
2320 tcp_send_fin(sk);
2321 }
2322}
2323EXPORT_SYMBOL(tcp_shutdown);
2324
2325bool tcp_check_oom(struct sock *sk, int shift)
2326{
2327 bool too_many_orphans, out_of_socket_memory;
2328
2329 too_many_orphans = tcp_too_many_orphans(sk, shift);
2330 out_of_socket_memory = tcp_out_of_memory(sk);
2331
2332 if (too_many_orphans)
2333 net_info_ratelimited("too many orphaned sockets\n");
2334 if (out_of_socket_memory)
2335 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
2336 return too_many_orphans || out_of_socket_memory;
2337}
2338
2339void tcp_close(struct sock *sk, long timeout)
2340{
2341 struct sk_buff *skb;
2342 int data_was_unread = 0;
2343 int state;
2344
2345 lock_sock(sk);
2346 sk->sk_shutdown = SHUTDOWN_MASK;
2347
2348 if (sk->sk_state == TCP_LISTEN) {
2349 tcp_set_state(sk, TCP_CLOSE);
2350
2351 /* Special case. */
2352 inet_csk_listen_stop(sk);
2353
2354 goto adjudge_to_death;
2355 }
2356
2357 /* We need to flush the recv. buffs. We do this only on the
2358 * descriptor close, not protocol-sourced closes, because the
2359 * reader process may not have drained the data yet!
2360 */
2361 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2362 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
2363
2364 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2365 len--;
2366 data_was_unread += len;
2367 __kfree_skb(skb);
2368 }
2369
2370 sk_mem_reclaim(sk);
2371
2372 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2373 if (sk->sk_state == TCP_CLOSE)
2374 goto adjudge_to_death;
2375
2376 /* As outlined in RFC 2525, section 2.17, we send a RST here because
2377 * data was lost. To witness the awful effects of the old behavior of
2378 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2379 * GET in an FTP client, suspend the process, wait for the client to
2380 * advertise a zero window, then kill -9 the FTP client, wheee...
2381 * Note: timeout is always zero in such a case.
2382 */
2383 if (unlikely(tcp_sk(sk)->repair)) {
2384 sk->sk_prot->disconnect(sk, 0);
2385 } else if (data_was_unread) {
2386 /* Unread data was tossed, zap the connection. */
2387 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2388 tcp_set_state(sk, TCP_CLOSE);
2389 tcp_send_active_reset(sk, sk->sk_allocation);
2390 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2391 /* Check zero linger _after_ checking for unread data. */
2392 sk->sk_prot->disconnect(sk, 0);
2393 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2394 } else if (tcp_close_state(sk)) {
2395 /* We FIN if the application ate all the data before
2396 * zapping the connection.
2397 */
2398
2399 /* RED-PEN. Formally speaking, we have broken TCP state
2400 * machine. State transitions:
2401 *
2402 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2403 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2404 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2405 *
2406 * are legal only when FIN has been sent (i.e. in window),
2407 * rather than queued out of window. Purists blame.
2408 *
2409 * F.e. "RFC state" is ESTABLISHED,
2410 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2411 *
2412 * The visible declinations are that sometimes
2413 * we enter time-wait state, when it is not required really
2414 * (harmless), do not send active resets, when they are
2415 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2416 * they look as CLOSING or LAST_ACK for Linux)
2417 * Probably, I missed some more holelets.
2418 * --ANK
2419 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2420 * in a single packet! (May consider it later but will
2421 * probably need API support or TCP_CORK SYN-ACK until
2422 * data is written and socket is closed.)
2423 */
2424 tcp_send_fin(sk);
2425 }
2426
2427 sk_stream_wait_close(sk, timeout);
2428
2429adjudge_to_death:
2430 state = sk->sk_state;
2431 sock_hold(sk);
2432 sock_orphan(sk);
2433
2434 local_bh_disable();
2435 bh_lock_sock(sk);
2436 /* remove backlog if any, without releasing ownership. */
2437 __release_sock(sk);
2438
2439 percpu_counter_inc(sk->sk_prot->orphan_count);
2440
2441 /* Have we already been destroyed by a softirq or backlog? */
2442 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2443 goto out;
2444
2445 /* This is a (useful) BSD violating of the RFC. There is a
2446 * problem with TCP as specified in that the other end could
2447 * keep a socket open forever with no application left this end.
2448 * We use a 1 minute timeout (about the same as BSD) then kill
2449 * our end. If they send after that then tough - BUT: long enough
2450 * that we won't make the old 4*rto = almost no time - whoops
2451 * reset mistake.
2452 *
2453 * Nope, it was not mistake. It is really desired behaviour
2454 * f.e. on http servers, when such sockets are useless, but
2455 * consume significant resources. Let's do it with special
2456 * linger2 option. --ANK
2457 */
2458
2459 if (sk->sk_state == TCP_FIN_WAIT2) {
2460 struct tcp_sock *tp = tcp_sk(sk);
2461 if (tp->linger2 < 0) {
2462 tcp_set_state(sk, TCP_CLOSE);
2463 tcp_send_active_reset(sk, GFP_ATOMIC);
2464 __NET_INC_STATS(sock_net(sk),
2465 LINUX_MIB_TCPABORTONLINGER);
2466 } else {
2467 const int tmo = tcp_fin_time(sk);
2468
2469 if (tmo > TCP_TIMEWAIT_LEN) {
2470 inet_csk_reset_keepalive_timer(sk,
2471 tmo - TCP_TIMEWAIT_LEN);
2472 } else {
2473 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2474 goto out;
2475 }
2476 }
2477 }
2478 if (sk->sk_state != TCP_CLOSE) {
2479 sk_mem_reclaim(sk);
2480 if (tcp_check_oom(sk, 0)) {
2481 tcp_set_state(sk, TCP_CLOSE);
2482 tcp_send_active_reset(sk, GFP_ATOMIC);
2483 __NET_INC_STATS(sock_net(sk),
2484 LINUX_MIB_TCPABORTONMEMORY);
2485 } else if (!check_net(sock_net(sk))) {
2486 /* Not possible to send reset; just close */
2487 tcp_set_state(sk, TCP_CLOSE);
2488 }
2489 }
2490
2491 if (sk->sk_state == TCP_CLOSE) {
2492 struct request_sock *req;
2493
2494 req = rcu_dereference_protected(tcp_sk(sk)->fastopen_rsk,
2495 lockdep_sock_is_held(sk));
2496 /* We could get here with a non-NULL req if the socket is
2497 * aborted (e.g., closed with unread data) before 3WHS
2498 * finishes.
2499 */
2500 if (req)
2501 reqsk_fastopen_remove(sk, req, false);
2502 inet_csk_destroy_sock(sk);
2503 }
2504 /* Otherwise, socket is reprieved until protocol close. */
2505
2506out:
2507 bh_unlock_sock(sk);
2508 local_bh_enable();
2509 release_sock(sk);
2510 sock_put(sk);
2511}
2512EXPORT_SYMBOL(tcp_close);
2513
2514/* These states need RST on ABORT according to RFC793 */
2515
2516static inline bool tcp_need_reset(int state)
2517{
2518 return (1 << state) &
2519 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2520 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2521}
2522
2523static void tcp_rtx_queue_purge(struct sock *sk)
2524{
2525 struct rb_node *p = rb_first(&sk->tcp_rtx_queue);
2526
2527 while (p) {
2528 struct sk_buff *skb = rb_to_skb(p);
2529
2530 p = rb_next(p);
2531 /* Since we are deleting whole queue, no need to
2532 * list_del(&skb->tcp_tsorted_anchor)
2533 */
2534 tcp_rtx_queue_unlink(skb, sk);
2535 sk_wmem_free_skb(sk, skb);
2536 }
2537}
2538
2539void tcp_write_queue_purge(struct sock *sk)
2540{
2541 struct sk_buff *skb;
2542
2543 tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
2544 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
2545 tcp_skb_tsorted_anchor_cleanup(skb);
2546 sk_wmem_free_skb(sk, skb);
2547 }
2548 tcp_rtx_queue_purge(sk);
2549 skb = sk->sk_tx_skb_cache;
2550 if (skb) {
2551 __kfree_skb(skb);
2552 sk->sk_tx_skb_cache = NULL;
2553 }
2554 INIT_LIST_HEAD(&tcp_sk(sk)->tsorted_sent_queue);
2555 sk_mem_reclaim(sk);
2556 tcp_clear_all_retrans_hints(tcp_sk(sk));
2557 tcp_sk(sk)->packets_out = 0;
2558 inet_csk(sk)->icsk_backoff = 0;
2559}
2560
2561int tcp_disconnect(struct sock *sk, int flags)
2562{
2563 struct inet_sock *inet = inet_sk(sk);
2564 struct inet_connection_sock *icsk = inet_csk(sk);
2565 struct tcp_sock *tp = tcp_sk(sk);
2566 int old_state = sk->sk_state;
2567 u32 seq;
2568
2569 if (old_state != TCP_CLOSE)
2570 tcp_set_state(sk, TCP_CLOSE);
2571
2572 /* ABORT function of RFC793 */
2573 if (old_state == TCP_LISTEN) {
2574 inet_csk_listen_stop(sk);
2575 } else if (unlikely(tp->repair)) {
2576 sk->sk_err = ECONNABORTED;
2577 } else if (tcp_need_reset(old_state) ||
2578 (tp->snd_nxt != tp->write_seq &&
2579 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2580 /* The last check adjusts for discrepancy of Linux wrt. RFC
2581 * states
2582 */
2583 tcp_send_active_reset(sk, gfp_any());
2584 sk->sk_err = ECONNRESET;
2585 } else if (old_state == TCP_SYN_SENT)
2586 sk->sk_err = ECONNRESET;
2587
2588 tcp_clear_xmit_timers(sk);
2589 __skb_queue_purge(&sk->sk_receive_queue);
2590 if (sk->sk_rx_skb_cache) {
2591 __kfree_skb(sk->sk_rx_skb_cache);
2592 sk->sk_rx_skb_cache = NULL;
2593 }
2594 WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
2595 tp->urg_data = 0;
2596 tcp_write_queue_purge(sk);
2597 tcp_fastopen_active_disable_ofo_check(sk);
2598 skb_rbtree_purge(&tp->out_of_order_queue);
2599
2600 inet->inet_dport = 0;
2601
2602 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2603 inet_reset_saddr(sk);
2604
2605 sk->sk_shutdown = 0;
2606 sock_reset_flag(sk, SOCK_DONE);
2607 tp->srtt_us = 0;
2608 tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
2609 tp->rcv_rtt_last_tsecr = 0;
2610
2611 seq = tp->write_seq + tp->max_window + 2;
2612 if (!seq)
2613 seq = 1;
2614 WRITE_ONCE(tp->write_seq, seq);
2615
2616 icsk->icsk_backoff = 0;
2617 tp->snd_cwnd = 2;
2618 icsk->icsk_probes_out = 0;
2619 icsk->icsk_rto = TCP_TIMEOUT_INIT;
2620 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2621 tp->snd_cwnd = TCP_INIT_CWND;
2622 tp->snd_cwnd_cnt = 0;
2623 tp->window_clamp = 0;
2624 tp->delivered_ce = 0;
2625 tcp_set_ca_state(sk, TCP_CA_Open);
2626 tp->is_sack_reneg = 0;
2627 tcp_clear_retrans(tp);
2628 inet_csk_delack_init(sk);
2629 /* Initialize rcv_mss to TCP_MIN_MSS to avoid division by 0
2630 * issue in __tcp_select_window()
2631 */
2632 icsk->icsk_ack.rcv_mss = TCP_MIN_MSS;
2633 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2634 __sk_dst_reset(sk);
2635 dst_release(sk->sk_rx_dst);
2636 sk->sk_rx_dst = NULL;
2637 tcp_saved_syn_free(tp);
2638 tp->compressed_ack = 0;
2639 tp->bytes_sent = 0;
2640 tp->bytes_acked = 0;
2641 tp->bytes_received = 0;
2642 tp->bytes_retrans = 0;
2643 tp->duplicate_sack[0].start_seq = 0;
2644 tp->duplicate_sack[0].end_seq = 0;
2645 tp->dsack_dups = 0;
2646 tp->reord_seen = 0;
2647 tp->retrans_out = 0;
2648 tp->sacked_out = 0;
2649 tp->tlp_high_seq = 0;
2650 tp->last_oow_ack_time = 0;
2651 /* There's a bubble in the pipe until at least the first ACK. */
2652 tp->app_limited = ~0U;
2653 tp->rack.mstamp = 0;
2654 tp->rack.advanced = 0;
2655 tp->rack.reo_wnd_steps = 1;
2656 tp->rack.last_delivered = 0;
2657 tp->rack.reo_wnd_persist = 0;
2658 tp->rack.dsack_seen = 0;
2659 tp->syn_data_acked = 0;
2660 tp->rx_opt.saw_tstamp = 0;
2661 tp->rx_opt.dsack = 0;
2662 tp->rx_opt.num_sacks = 0;
2663 tp->rcv_ooopack = 0;
2664
2665
2666 /* Clean up fastopen related fields */
2667 tcp_free_fastopen_req(tp);
2668 inet->defer_connect = 0;
2669
2670 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2671
2672 if (sk->sk_frag.page) {
2673 put_page(sk->sk_frag.page);
2674 sk->sk_frag.page = NULL;
2675 sk->sk_frag.offset = 0;
2676 }
2677
2678 sk->sk_error_report(sk);
2679 return 0;
2680}
2681EXPORT_SYMBOL(tcp_disconnect);
2682
2683static inline bool tcp_can_repair_sock(const struct sock *sk)
2684{
2685 return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
2686 (sk->sk_state != TCP_LISTEN);
2687}
2688
2689static int tcp_repair_set_window(struct tcp_sock *tp, char __user *optbuf, int len)
2690{
2691 struct tcp_repair_window opt;
2692
2693 if (!tp->repair)
2694 return -EPERM;
2695
2696 if (len != sizeof(opt))
2697 return -EINVAL;
2698
2699 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2700 return -EFAULT;
2701
2702 if (opt.max_window < opt.snd_wnd)
2703 return -EINVAL;
2704
2705 if (after(opt.snd_wl1, tp->rcv_nxt + opt.rcv_wnd))
2706 return -EINVAL;
2707
2708 if (after(opt.rcv_wup, tp->rcv_nxt))
2709 return -EINVAL;
2710
2711 tp->snd_wl1 = opt.snd_wl1;
2712 tp->snd_wnd = opt.snd_wnd;
2713 tp->max_window = opt.max_window;
2714
2715 tp->rcv_wnd = opt.rcv_wnd;
2716 tp->rcv_wup = opt.rcv_wup;
2717
2718 return 0;
2719}
2720
2721static int tcp_repair_options_est(struct sock *sk,
2722 struct tcp_repair_opt __user *optbuf, unsigned int len)
2723{
2724 struct tcp_sock *tp = tcp_sk(sk);
2725 struct tcp_repair_opt opt;
2726
2727 while (len >= sizeof(opt)) {
2728 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2729 return -EFAULT;
2730
2731 optbuf++;
2732 len -= sizeof(opt);
2733
2734 switch (opt.opt_code) {
2735 case TCPOPT_MSS:
2736 tp->rx_opt.mss_clamp = opt.opt_val;
2737 tcp_mtup_init(sk);
2738 break;
2739 case TCPOPT_WINDOW:
2740 {
2741 u16 snd_wscale = opt.opt_val & 0xFFFF;
2742 u16 rcv_wscale = opt.opt_val >> 16;
2743
2744 if (snd_wscale > TCP_MAX_WSCALE || rcv_wscale > TCP_MAX_WSCALE)
2745 return -EFBIG;
2746
2747 tp->rx_opt.snd_wscale = snd_wscale;
2748 tp->rx_opt.rcv_wscale = rcv_wscale;
2749 tp->rx_opt.wscale_ok = 1;
2750 }
2751 break;
2752 case TCPOPT_SACK_PERM:
2753 if (opt.opt_val != 0)
2754 return -EINVAL;
2755
2756 tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2757 break;
2758 case TCPOPT_TIMESTAMP:
2759 if (opt.opt_val != 0)
2760 return -EINVAL;
2761
2762 tp->rx_opt.tstamp_ok = 1;
2763 break;
2764 }
2765 }
2766
2767 return 0;
2768}
2769
2770DEFINE_STATIC_KEY_FALSE(tcp_tx_delay_enabled);
2771EXPORT_SYMBOL(tcp_tx_delay_enabled);
2772
2773static void tcp_enable_tx_delay(void)
2774{
2775 if (!static_branch_unlikely(&tcp_tx_delay_enabled)) {
2776 static int __tcp_tx_delay_enabled = 0;
2777
2778 if (cmpxchg(&__tcp_tx_delay_enabled, 0, 1) == 0) {
2779 static_branch_enable(&tcp_tx_delay_enabled);
2780 pr_info("TCP_TX_DELAY enabled\n");
2781 }
2782 }
2783}
2784
2785/*
2786 * Socket option code for TCP.
2787 */
2788static int do_tcp_setsockopt(struct sock *sk, int level,
2789 int optname, char __user *optval, unsigned int optlen)
2790{
2791 struct tcp_sock *tp = tcp_sk(sk);
2792 struct inet_connection_sock *icsk = inet_csk(sk);
2793 struct net *net = sock_net(sk);
2794 int val;
2795 int err = 0;
2796
2797 /* These are data/string values, all the others are ints */
2798 switch (optname) {
2799 case TCP_CONGESTION: {
2800 char name[TCP_CA_NAME_MAX];
2801
2802 if (optlen < 1)
2803 return -EINVAL;
2804
2805 val = strncpy_from_user(name, optval,
2806 min_t(long, TCP_CA_NAME_MAX-1, optlen));
2807 if (val < 0)
2808 return -EFAULT;
2809 name[val] = 0;
2810
2811 lock_sock(sk);
2812 err = tcp_set_congestion_control(sk, name, true, true,
2813 ns_capable(sock_net(sk)->user_ns,
2814 CAP_NET_ADMIN));
2815 release_sock(sk);
2816 return err;
2817 }
2818 case TCP_ULP: {
2819 char name[TCP_ULP_NAME_MAX];
2820
2821 if (optlen < 1)
2822 return -EINVAL;
2823
2824 val = strncpy_from_user(name, optval,
2825 min_t(long, TCP_ULP_NAME_MAX - 1,
2826 optlen));
2827 if (val < 0)
2828 return -EFAULT;
2829 name[val] = 0;
2830
2831 lock_sock(sk);
2832 err = tcp_set_ulp(sk, name);
2833 release_sock(sk);
2834 return err;
2835 }
2836 case TCP_FASTOPEN_KEY: {
2837 __u8 key[TCP_FASTOPEN_KEY_BUF_LENGTH];
2838 __u8 *backup_key = NULL;
2839
2840 /* Allow a backup key as well to facilitate key rotation
2841 * First key is the active one.
2842 */
2843 if (optlen != TCP_FASTOPEN_KEY_LENGTH &&
2844 optlen != TCP_FASTOPEN_KEY_BUF_LENGTH)
2845 return -EINVAL;
2846
2847 if (copy_from_user(key, optval, optlen))
2848 return -EFAULT;
2849
2850 if (optlen == TCP_FASTOPEN_KEY_BUF_LENGTH)
2851 backup_key = key + TCP_FASTOPEN_KEY_LENGTH;
2852
2853 return tcp_fastopen_reset_cipher(net, sk, key, backup_key);
2854 }
2855 default:
2856 /* fallthru */
2857 break;
2858 }
2859
2860 if (optlen < sizeof(int))
2861 return -EINVAL;
2862
2863 if (get_user(val, (int __user *)optval))
2864 return -EFAULT;
2865
2866 lock_sock(sk);
2867
2868 switch (optname) {
2869 case TCP_MAXSEG:
2870 /* Values greater than interface MTU won't take effect. However
2871 * at the point when this call is done we typically don't yet
2872 * know which interface is going to be used
2873 */
2874 if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) {
2875 err = -EINVAL;
2876 break;
2877 }
2878 tp->rx_opt.user_mss = val;
2879 break;
2880
2881 case TCP_NODELAY:
2882 if (val) {
2883 /* TCP_NODELAY is weaker than TCP_CORK, so that
2884 * this option on corked socket is remembered, but
2885 * it is not activated until cork is cleared.
2886 *
2887 * However, when TCP_NODELAY is set we make
2888 * an explicit push, which overrides even TCP_CORK
2889 * for currently queued segments.
2890 */
2891 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2892 tcp_push_pending_frames(sk);
2893 } else {
2894 tp->nonagle &= ~TCP_NAGLE_OFF;
2895 }
2896 break;
2897
2898 case TCP_THIN_LINEAR_TIMEOUTS:
2899 if (val < 0 || val > 1)
2900 err = -EINVAL;
2901 else
2902 tp->thin_lto = val;
2903 break;
2904
2905 case TCP_THIN_DUPACK:
2906 if (val < 0 || val > 1)
2907 err = -EINVAL;
2908 break;
2909
2910 case TCP_REPAIR:
2911 if (!tcp_can_repair_sock(sk))
2912 err = -EPERM;
2913 else if (val == TCP_REPAIR_ON) {
2914 tp->repair = 1;
2915 sk->sk_reuse = SK_FORCE_REUSE;
2916 tp->repair_queue = TCP_NO_QUEUE;
2917 } else if (val == TCP_REPAIR_OFF) {
2918 tp->repair = 0;
2919 sk->sk_reuse = SK_NO_REUSE;
2920 tcp_send_window_probe(sk);
2921 } else if (val == TCP_REPAIR_OFF_NO_WP) {
2922 tp->repair = 0;
2923 sk->sk_reuse = SK_NO_REUSE;
2924 } else
2925 err = -EINVAL;
2926
2927 break;
2928
2929 case TCP_REPAIR_QUEUE:
2930 if (!tp->repair)
2931 err = -EPERM;
2932 else if ((unsigned int)val < TCP_QUEUES_NR)
2933 tp->repair_queue = val;
2934 else
2935 err = -EINVAL;
2936 break;
2937
2938 case TCP_QUEUE_SEQ:
2939 if (sk->sk_state != TCP_CLOSE)
2940 err = -EPERM;
2941 else if (tp->repair_queue == TCP_SEND_QUEUE)
2942 WRITE_ONCE(tp->write_seq, val);
2943 else if (tp->repair_queue == TCP_RECV_QUEUE)
2944 WRITE_ONCE(tp->rcv_nxt, val);
2945 else
2946 err = -EINVAL;
2947 break;
2948
2949 case TCP_REPAIR_OPTIONS:
2950 if (!tp->repair)
2951 err = -EINVAL;
2952 else if (sk->sk_state == TCP_ESTABLISHED)
2953 err = tcp_repair_options_est(sk,
2954 (struct tcp_repair_opt __user *)optval,
2955 optlen);
2956 else
2957 err = -EPERM;
2958 break;
2959
2960 case TCP_CORK:
2961 /* When set indicates to always queue non-full frames.
2962 * Later the user clears this option and we transmit
2963 * any pending partial frames in the queue. This is
2964 * meant to be used alongside sendfile() to get properly
2965 * filled frames when the user (for example) must write
2966 * out headers with a write() call first and then use
2967 * sendfile to send out the data parts.
2968 *
2969 * TCP_CORK can be set together with TCP_NODELAY and it is
2970 * stronger than TCP_NODELAY.
2971 */
2972 if (val) {
2973 tp->nonagle |= TCP_NAGLE_CORK;
2974 } else {
2975 tp->nonagle &= ~TCP_NAGLE_CORK;
2976 if (tp->nonagle&TCP_NAGLE_OFF)
2977 tp->nonagle |= TCP_NAGLE_PUSH;
2978 tcp_push_pending_frames(sk);
2979 }
2980 break;
2981
2982 case TCP_KEEPIDLE:
2983 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2984 err = -EINVAL;
2985 else {
2986 tp->keepalive_time = val * HZ;
2987 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2988 !((1 << sk->sk_state) &
2989 (TCPF_CLOSE | TCPF_LISTEN))) {
2990 u32 elapsed = keepalive_time_elapsed(tp);
2991 if (tp->keepalive_time > elapsed)
2992 elapsed = tp->keepalive_time - elapsed;
2993 else
2994 elapsed = 0;
2995 inet_csk_reset_keepalive_timer(sk, elapsed);
2996 }
2997 }
2998 break;
2999 case TCP_KEEPINTVL:
3000 if (val < 1 || val > MAX_TCP_KEEPINTVL)
3001 err = -EINVAL;
3002 else
3003 tp->keepalive_intvl = val * HZ;
3004 break;
3005 case TCP_KEEPCNT:
3006 if (val < 1 || val > MAX_TCP_KEEPCNT)
3007 err = -EINVAL;
3008 else
3009 tp->keepalive_probes = val;
3010 break;
3011 case TCP_SYNCNT:
3012 if (val < 1 || val > MAX_TCP_SYNCNT)
3013 err = -EINVAL;
3014 else
3015 icsk->icsk_syn_retries = val;
3016 break;
3017
3018 case TCP_SAVE_SYN:
3019 if (val < 0 || val > 1)
3020 err = -EINVAL;
3021 else
3022 tp->save_syn = val;
3023 break;
3024
3025 case TCP_LINGER2:
3026 if (val < 0)
3027 tp->linger2 = -1;
3028 else if (val > net->ipv4.sysctl_tcp_fin_timeout / HZ)
3029 tp->linger2 = 0;
3030 else
3031 tp->linger2 = val * HZ;
3032 break;
3033
3034 case TCP_DEFER_ACCEPT:
3035 /* Translate value in seconds to number of retransmits */
3036 icsk->icsk_accept_queue.rskq_defer_accept =
3037 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
3038 TCP_RTO_MAX / HZ);
3039 break;
3040
3041 case TCP_WINDOW_CLAMP:
3042 if (!val) {
3043 if (sk->sk_state != TCP_CLOSE) {
3044 err = -EINVAL;
3045 break;
3046 }
3047 tp->window_clamp = 0;
3048 } else
3049 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
3050 SOCK_MIN_RCVBUF / 2 : val;
3051 break;
3052
3053 case TCP_QUICKACK:
3054 if (!val) {
3055 inet_csk_enter_pingpong_mode(sk);
3056 } else {
3057 inet_csk_exit_pingpong_mode(sk);
3058 if ((1 << sk->sk_state) &
3059 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
3060 inet_csk_ack_scheduled(sk)) {
3061 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
3062 tcp_cleanup_rbuf(sk, 1);
3063 if (!(val & 1))
3064 inet_csk_enter_pingpong_mode(sk);
3065 }
3066 }
3067 break;
3068
3069#ifdef CONFIG_TCP_MD5SIG
3070 case TCP_MD5SIG:
3071 case TCP_MD5SIG_EXT:
3072 if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))
3073 err = tp->af_specific->md5_parse(sk, optname, optval, optlen);
3074 else
3075 err = -EINVAL;
3076 break;
3077#endif
3078 case TCP_USER_TIMEOUT:
3079 /* Cap the max time in ms TCP will retry or probe the window
3080 * before giving up and aborting (ETIMEDOUT) a connection.
3081 */
3082 if (val < 0)
3083 err = -EINVAL;
3084 else
3085 icsk->icsk_user_timeout = val;
3086 break;
3087
3088 case TCP_FASTOPEN:
3089 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
3090 TCPF_LISTEN))) {
3091 tcp_fastopen_init_key_once(net);
3092
3093 fastopen_queue_tune(sk, val);
3094 } else {
3095 err = -EINVAL;
3096 }
3097 break;
3098 case TCP_FASTOPEN_CONNECT:
3099 if (val > 1 || val < 0) {
3100 err = -EINVAL;
3101 } else if (net->ipv4.sysctl_tcp_fastopen & TFO_CLIENT_ENABLE) {
3102 if (sk->sk_state == TCP_CLOSE)
3103 tp->fastopen_connect = val;
3104 else
3105 err = -EINVAL;
3106 } else {
3107 err = -EOPNOTSUPP;
3108 }
3109 break;
3110 case TCP_FASTOPEN_NO_COOKIE:
3111 if (val > 1 || val < 0)
3112 err = -EINVAL;
3113 else if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
3114 err = -EINVAL;
3115 else
3116 tp->fastopen_no_cookie = val;
3117 break;
3118 case TCP_TIMESTAMP:
3119 if (!tp->repair)
3120 err = -EPERM;
3121 else
3122 tp->tsoffset = val - tcp_time_stamp_raw();
3123 break;
3124 case TCP_REPAIR_WINDOW:
3125 err = tcp_repair_set_window(tp, optval, optlen);
3126 break;
3127 case TCP_NOTSENT_LOWAT:
3128 tp->notsent_lowat = val;
3129 sk->sk_write_space(sk);
3130 break;
3131 case TCP_INQ:
3132 if (val > 1 || val < 0)
3133 err = -EINVAL;
3134 else
3135 tp->recvmsg_inq = val;
3136 break;
3137 case TCP_TX_DELAY:
3138 if (val)
3139 tcp_enable_tx_delay();
3140 tp->tcp_tx_delay = val;
3141 break;
3142 default:
3143 err = -ENOPROTOOPT;
3144 break;
3145 }
3146
3147 release_sock(sk);
3148 return err;
3149}
3150
3151int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
3152 unsigned int optlen)
3153{
3154 const struct inet_connection_sock *icsk = inet_csk(sk);
3155
3156 if (level != SOL_TCP)
3157 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
3158 optval, optlen);
3159 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
3160}
3161EXPORT_SYMBOL(tcp_setsockopt);
3162
3163#ifdef CONFIG_COMPAT
3164int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
3165 char __user *optval, unsigned int optlen)
3166{
3167 if (level != SOL_TCP)
3168 return inet_csk_compat_setsockopt(sk, level, optname,
3169 optval, optlen);
3170 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
3171}
3172EXPORT_SYMBOL(compat_tcp_setsockopt);
3173#endif
3174
3175static void tcp_get_info_chrono_stats(const struct tcp_sock *tp,
3176 struct tcp_info *info)
3177{
3178 u64 stats[__TCP_CHRONO_MAX], total = 0;
3179 enum tcp_chrono i;
3180
3181 for (i = TCP_CHRONO_BUSY; i < __TCP_CHRONO_MAX; ++i) {
3182 stats[i] = tp->chrono_stat[i - 1];
3183 if (i == tp->chrono_type)
3184 stats[i] += tcp_jiffies32 - tp->chrono_start;
3185 stats[i] *= USEC_PER_SEC / HZ;
3186 total += stats[i];
3187 }
3188
3189 info->tcpi_busy_time = total;
3190 info->tcpi_rwnd_limited = stats[TCP_CHRONO_RWND_LIMITED];
3191 info->tcpi_sndbuf_limited = stats[TCP_CHRONO_SNDBUF_LIMITED];
3192}
3193
3194/* Return information about state of tcp endpoint in API format. */
3195void tcp_get_info(struct sock *sk, struct tcp_info *info)
3196{
3197 const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
3198 const struct inet_connection_sock *icsk = inet_csk(sk);
3199 unsigned long rate;
3200 u32 now;
3201 u64 rate64;
3202 bool slow;
3203
3204 memset(info, 0, sizeof(*info));
3205 if (sk->sk_type != SOCK_STREAM)
3206 return;
3207
3208 info->tcpi_state = inet_sk_state_load(sk);
3209
3210 /* Report meaningful fields for all TCP states, including listeners */
3211 rate = READ_ONCE(sk->sk_pacing_rate);
3212 rate64 = (rate != ~0UL) ? rate : ~0ULL;
3213 info->tcpi_pacing_rate = rate64;
3214
3215 rate = READ_ONCE(sk->sk_max_pacing_rate);
3216 rate64 = (rate != ~0UL) ? rate : ~0ULL;
3217 info->tcpi_max_pacing_rate = rate64;
3218
3219 info->tcpi_reordering = tp->reordering;
3220 info->tcpi_snd_cwnd = tp->snd_cwnd;
3221
3222 if (info->tcpi_state == TCP_LISTEN) {
3223 /* listeners aliased fields :
3224 * tcpi_unacked -> Number of children ready for accept()
3225 * tcpi_sacked -> max backlog
3226 */
3227 info->tcpi_unacked = sk->sk_ack_backlog;
3228 info->tcpi_sacked = sk->sk_max_ack_backlog;
3229 return;
3230 }
3231
3232 slow = lock_sock_fast(sk);
3233
3234 info->tcpi_ca_state = icsk->icsk_ca_state;
3235 info->tcpi_retransmits = icsk->icsk_retransmits;
3236 info->tcpi_probes = icsk->icsk_probes_out;
3237 info->tcpi_backoff = icsk->icsk_backoff;
3238
3239 if (tp->rx_opt.tstamp_ok)
3240 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
3241 if (tcp_is_sack(tp))
3242 info->tcpi_options |= TCPI_OPT_SACK;
3243 if (tp->rx_opt.wscale_ok) {
3244 info->tcpi_options |= TCPI_OPT_WSCALE;
3245 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
3246 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
3247 }
3248
3249 if (tp->ecn_flags & TCP_ECN_OK)
3250 info->tcpi_options |= TCPI_OPT_ECN;
3251 if (tp->ecn_flags & TCP_ECN_SEEN)
3252 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
3253 if (tp->syn_data_acked)
3254 info->tcpi_options |= TCPI_OPT_SYN_DATA;
3255
3256 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
3257 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
3258 info->tcpi_snd_mss = tp->mss_cache;
3259 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
3260
3261 info->tcpi_unacked = tp->packets_out;
3262 info->tcpi_sacked = tp->sacked_out;
3263
3264 info->tcpi_lost = tp->lost_out;
3265 info->tcpi_retrans = tp->retrans_out;
3266
3267 now = tcp_jiffies32;
3268 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
3269 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
3270 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
3271
3272 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
3273 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
3274 info->tcpi_rtt = tp->srtt_us >> 3;
3275 info->tcpi_rttvar = tp->mdev_us >> 2;
3276 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
3277 info->tcpi_advmss = tp->advmss;
3278
3279 info->tcpi_rcv_rtt = tp->rcv_rtt_est.rtt_us >> 3;
3280 info->tcpi_rcv_space = tp->rcvq_space.space;
3281
3282 info->tcpi_total_retrans = tp->total_retrans;
3283
3284 info->tcpi_bytes_acked = tp->bytes_acked;
3285 info->tcpi_bytes_received = tp->bytes_received;
3286 info->tcpi_notsent_bytes = max_t(int, 0, tp->write_seq - tp->snd_nxt);
3287 tcp_get_info_chrono_stats(tp, info);
3288
3289 info->tcpi_segs_out = tp->segs_out;
3290 info->tcpi_segs_in = tp->segs_in;
3291
3292 info->tcpi_min_rtt = tcp_min_rtt(tp);
3293 info->tcpi_data_segs_in = tp->data_segs_in;
3294 info->tcpi_data_segs_out = tp->data_segs_out;
3295
3296 info->tcpi_delivery_rate_app_limited = tp->rate_app_limited ? 1 : 0;
3297 rate64 = tcp_compute_delivery_rate(tp);
3298 if (rate64)
3299 info->tcpi_delivery_rate = rate64;
3300 info->tcpi_delivered = tp->delivered;
3301 info->tcpi_delivered_ce = tp->delivered_ce;
3302 info->tcpi_bytes_sent = tp->bytes_sent;
3303 info->tcpi_bytes_retrans = tp->bytes_retrans;
3304 info->tcpi_dsack_dups = tp->dsack_dups;
3305 info->tcpi_reord_seen = tp->reord_seen;
3306 info->tcpi_rcv_ooopack = tp->rcv_ooopack;
3307 info->tcpi_snd_wnd = tp->snd_wnd;
3308 unlock_sock_fast(sk, slow);
3309}
3310EXPORT_SYMBOL_GPL(tcp_get_info);
3311
3312static size_t tcp_opt_stats_get_size(void)
3313{
3314 return
3315 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BUSY */
3316 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_RWND_LIMITED */
3317 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_SNDBUF_LIMITED */
3318 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_DATA_SEGS_OUT */
3319 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_TOTAL_RETRANS */
3320 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_PACING_RATE */
3321 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_DELIVERY_RATE */
3322 nla_total_size(sizeof(u32)) + /* TCP_NLA_SND_CWND */
3323 nla_total_size(sizeof(u32)) + /* TCP_NLA_REORDERING */
3324 nla_total_size(sizeof(u32)) + /* TCP_NLA_MIN_RTT */
3325 nla_total_size(sizeof(u8)) + /* TCP_NLA_RECUR_RETRANS */
3326 nla_total_size(sizeof(u8)) + /* TCP_NLA_DELIVERY_RATE_APP_LMT */
3327 nla_total_size(sizeof(u32)) + /* TCP_NLA_SNDQ_SIZE */
3328 nla_total_size(sizeof(u8)) + /* TCP_NLA_CA_STATE */
3329 nla_total_size(sizeof(u32)) + /* TCP_NLA_SND_SSTHRESH */
3330 nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED */
3331 nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED_CE */
3332 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_SENT */
3333 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_RETRANS */
3334 nla_total_size(sizeof(u32)) + /* TCP_NLA_DSACK_DUPS */
3335 nla_total_size(sizeof(u32)) + /* TCP_NLA_REORD_SEEN */
3336 nla_total_size(sizeof(u32)) + /* TCP_NLA_SRTT */
3337 0;
3338}
3339
3340struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk)
3341{
3342 const struct tcp_sock *tp = tcp_sk(sk);
3343 struct sk_buff *stats;
3344 struct tcp_info info;
3345 unsigned long rate;
3346 u64 rate64;
3347
3348 stats = alloc_skb(tcp_opt_stats_get_size(), GFP_ATOMIC);
3349 if (!stats)
3350 return NULL;
3351
3352 tcp_get_info_chrono_stats(tp, &info);
3353 nla_put_u64_64bit(stats, TCP_NLA_BUSY,
3354 info.tcpi_busy_time, TCP_NLA_PAD);
3355 nla_put_u64_64bit(stats, TCP_NLA_RWND_LIMITED,
3356 info.tcpi_rwnd_limited, TCP_NLA_PAD);
3357 nla_put_u64_64bit(stats, TCP_NLA_SNDBUF_LIMITED,
3358 info.tcpi_sndbuf_limited, TCP_NLA_PAD);
3359 nla_put_u64_64bit(stats, TCP_NLA_DATA_SEGS_OUT,
3360 tp->data_segs_out, TCP_NLA_PAD);
3361 nla_put_u64_64bit(stats, TCP_NLA_TOTAL_RETRANS,
3362 tp->total_retrans, TCP_NLA_PAD);
3363
3364 rate = READ_ONCE(sk->sk_pacing_rate);
3365 rate64 = (rate != ~0UL) ? rate : ~0ULL;
3366 nla_put_u64_64bit(stats, TCP_NLA_PACING_RATE, rate64, TCP_NLA_PAD);
3367
3368 rate64 = tcp_compute_delivery_rate(tp);
3369 nla_put_u64_64bit(stats, TCP_NLA_DELIVERY_RATE, rate64, TCP_NLA_PAD);
3370
3371 nla_put_u32(stats, TCP_NLA_SND_CWND, tp->snd_cwnd);
3372 nla_put_u32(stats, TCP_NLA_REORDERING, tp->reordering);
3373 nla_put_u32(stats, TCP_NLA_MIN_RTT, tcp_min_rtt(tp));
3374
3375 nla_put_u8(stats, TCP_NLA_RECUR_RETRANS, inet_csk(sk)->icsk_retransmits);
3376 nla_put_u8(stats, TCP_NLA_DELIVERY_RATE_APP_LMT, !!tp->rate_app_limited);
3377 nla_put_u32(stats, TCP_NLA_SND_SSTHRESH, tp->snd_ssthresh);
3378 nla_put_u32(stats, TCP_NLA_DELIVERED, tp->delivered);
3379 nla_put_u32(stats, TCP_NLA_DELIVERED_CE, tp->delivered_ce);
3380
3381 nla_put_u32(stats, TCP_NLA_SNDQ_SIZE, tp->write_seq - tp->snd_una);
3382 nla_put_u8(stats, TCP_NLA_CA_STATE, inet_csk(sk)->icsk_ca_state);
3383
3384 nla_put_u64_64bit(stats, TCP_NLA_BYTES_SENT, tp->bytes_sent,
3385 TCP_NLA_PAD);
3386 nla_put_u64_64bit(stats, TCP_NLA_BYTES_RETRANS, tp->bytes_retrans,
3387 TCP_NLA_PAD);
3388 nla_put_u32(stats, TCP_NLA_DSACK_DUPS, tp->dsack_dups);
3389 nla_put_u32(stats, TCP_NLA_REORD_SEEN, tp->reord_seen);
3390 nla_put_u32(stats, TCP_NLA_SRTT, tp->srtt_us >> 3);
3391
3392 return stats;
3393}
3394
3395static int do_tcp_getsockopt(struct sock *sk, int level,
3396 int optname, char __user *optval, int __user *optlen)
3397{
3398 struct inet_connection_sock *icsk = inet_csk(sk);
3399 struct tcp_sock *tp = tcp_sk(sk);
3400 struct net *net = sock_net(sk);
3401 int val, len;
3402
3403 if (get_user(len, optlen))
3404 return -EFAULT;
3405
3406 len = min_t(unsigned int, len, sizeof(int));
3407
3408 if (len < 0)
3409 return -EINVAL;
3410
3411 switch (optname) {
3412 case TCP_MAXSEG:
3413 val = tp->mss_cache;
3414 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
3415 val = tp->rx_opt.user_mss;
3416 if (tp->repair)
3417 val = tp->rx_opt.mss_clamp;
3418 break;
3419 case TCP_NODELAY:
3420 val = !!(tp->nonagle&TCP_NAGLE_OFF);
3421 break;
3422 case TCP_CORK:
3423 val = !!(tp->nonagle&TCP_NAGLE_CORK);
3424 break;
3425 case TCP_KEEPIDLE:
3426 val = keepalive_time_when(tp) / HZ;
3427 break;
3428 case TCP_KEEPINTVL:
3429 val = keepalive_intvl_when(tp) / HZ;
3430 break;
3431 case TCP_KEEPCNT:
3432 val = keepalive_probes(tp);
3433 break;
3434 case TCP_SYNCNT:
3435 val = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries;
3436 break;
3437 case TCP_LINGER2:
3438 val = tp->linger2;
3439 if (val >= 0)
3440 val = (val ? : net->ipv4.sysctl_tcp_fin_timeout) / HZ;
3441 break;
3442 case TCP_DEFER_ACCEPT:
3443 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
3444 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
3445 break;
3446 case TCP_WINDOW_CLAMP:
3447 val = tp->window_clamp;
3448 break;
3449 case TCP_INFO: {
3450 struct tcp_info info;
3451
3452 if (get_user(len, optlen))
3453 return -EFAULT;
3454
3455 tcp_get_info(sk, &info);
3456
3457 len = min_t(unsigned int, len, sizeof(info));
3458 if (put_user(len, optlen))
3459 return -EFAULT;
3460 if (copy_to_user(optval, &info, len))
3461 return -EFAULT;
3462 return 0;
3463 }
3464 case TCP_CC_INFO: {
3465 const struct tcp_congestion_ops *ca_ops;
3466 union tcp_cc_info info;
3467 size_t sz = 0;
3468 int attr;
3469
3470 if (get_user(len, optlen))
3471 return -EFAULT;
3472
3473 ca_ops = icsk->icsk_ca_ops;
3474 if (ca_ops && ca_ops->get_info)
3475 sz = ca_ops->get_info(sk, ~0U, &attr, &info);
3476
3477 len = min_t(unsigned int, len, sz);
3478 if (put_user(len, optlen))
3479 return -EFAULT;
3480 if (copy_to_user(optval, &info, len))
3481 return -EFAULT;
3482 return 0;
3483 }
3484 case TCP_QUICKACK:
3485 val = !inet_csk_in_pingpong_mode(sk);
3486 break;
3487
3488 case TCP_CONGESTION:
3489 if (get_user(len, optlen))
3490 return -EFAULT;
3491 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
3492 if (put_user(len, optlen))
3493 return -EFAULT;
3494 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
3495 return -EFAULT;
3496 return 0;
3497
3498 case TCP_ULP:
3499 if (get_user(len, optlen))
3500 return -EFAULT;
3501 len = min_t(unsigned int, len, TCP_ULP_NAME_MAX);
3502 if (!icsk->icsk_ulp_ops) {
3503 if (put_user(0, optlen))
3504 return -EFAULT;
3505 return 0;
3506 }
3507 if (put_user(len, optlen))
3508 return -EFAULT;
3509 if (copy_to_user(optval, icsk->icsk_ulp_ops->name, len))
3510 return -EFAULT;
3511 return 0;
3512
3513 case TCP_FASTOPEN_KEY: {
3514 __u8 key[TCP_FASTOPEN_KEY_BUF_LENGTH];
3515 struct tcp_fastopen_context *ctx;
3516 unsigned int key_len = 0;
3517
3518 if (get_user(len, optlen))
3519 return -EFAULT;
3520
3521 rcu_read_lock();
3522 ctx = rcu_dereference(icsk->icsk_accept_queue.fastopenq.ctx);
3523 if (ctx) {
3524 key_len = tcp_fastopen_context_len(ctx) *
3525 TCP_FASTOPEN_KEY_LENGTH;
3526 memcpy(&key[0], &ctx->key[0], key_len);
3527 }
3528 rcu_read_unlock();
3529
3530 len = min_t(unsigned int, len, key_len);
3531 if (put_user(len, optlen))
3532 return -EFAULT;
3533 if (copy_to_user(optval, key, len))
3534 return -EFAULT;
3535 return 0;
3536 }
3537 case TCP_THIN_LINEAR_TIMEOUTS:
3538 val = tp->thin_lto;
3539 break;
3540
3541 case TCP_THIN_DUPACK:
3542 val = 0;
3543 break;
3544
3545 case TCP_REPAIR:
3546 val = tp->repair;
3547 break;
3548
3549 case TCP_REPAIR_QUEUE:
3550 if (tp->repair)
3551 val = tp->repair_queue;
3552 else
3553 return -EINVAL;
3554 break;
3555
3556 case TCP_REPAIR_WINDOW: {
3557 struct tcp_repair_window opt;
3558
3559 if (get_user(len, optlen))
3560 return -EFAULT;
3561
3562 if (len != sizeof(opt))
3563 return -EINVAL;
3564
3565 if (!tp->repair)
3566 return -EPERM;
3567
3568 opt.snd_wl1 = tp->snd_wl1;
3569 opt.snd_wnd = tp->snd_wnd;
3570 opt.max_window = tp->max_window;
3571 opt.rcv_wnd = tp->rcv_wnd;
3572 opt.rcv_wup = tp->rcv_wup;
3573
3574 if (copy_to_user(optval, &opt, len))
3575 return -EFAULT;
3576 return 0;
3577 }
3578 case TCP_QUEUE_SEQ:
3579 if (tp->repair_queue == TCP_SEND_QUEUE)
3580 val = tp->write_seq;
3581 else if (tp->repair_queue == TCP_RECV_QUEUE)
3582 val = tp->rcv_nxt;
3583 else
3584 return -EINVAL;
3585 break;
3586
3587 case TCP_USER_TIMEOUT:
3588 val = icsk->icsk_user_timeout;
3589 break;
3590
3591 case TCP_FASTOPEN:
3592 val = icsk->icsk_accept_queue.fastopenq.max_qlen;
3593 break;
3594
3595 case TCP_FASTOPEN_CONNECT:
3596 val = tp->fastopen_connect;
3597 break;
3598
3599 case TCP_FASTOPEN_NO_COOKIE:
3600 val = tp->fastopen_no_cookie;
3601 break;
3602
3603 case TCP_TX_DELAY:
3604 val = tp->tcp_tx_delay;
3605 break;
3606
3607 case TCP_TIMESTAMP:
3608 val = tcp_time_stamp_raw() + tp->tsoffset;
3609 break;
3610 case TCP_NOTSENT_LOWAT:
3611 val = tp->notsent_lowat;
3612 break;
3613 case TCP_INQ:
3614 val = tp->recvmsg_inq;
3615 break;
3616 case TCP_SAVE_SYN:
3617 val = tp->save_syn;
3618 break;
3619 case TCP_SAVED_SYN: {
3620 if (get_user(len, optlen))
3621 return -EFAULT;
3622
3623 lock_sock(sk);
3624 if (tp->saved_syn) {
3625 if (len < tp->saved_syn[0]) {
3626 if (put_user(tp->saved_syn[0], optlen)) {
3627 release_sock(sk);
3628 return -EFAULT;
3629 }
3630 release_sock(sk);
3631 return -EINVAL;
3632 }
3633 len = tp->saved_syn[0];
3634 if (put_user(len, optlen)) {
3635 release_sock(sk);
3636 return -EFAULT;
3637 }
3638 if (copy_to_user(optval, tp->saved_syn + 1, len)) {
3639 release_sock(sk);
3640 return -EFAULT;
3641 }
3642 tcp_saved_syn_free(tp);
3643 release_sock(sk);
3644 } else {
3645 release_sock(sk);
3646 len = 0;
3647 if (put_user(len, optlen))
3648 return -EFAULT;
3649 }
3650 return 0;
3651 }
3652#ifdef CONFIG_MMU
3653 case TCP_ZEROCOPY_RECEIVE: {
3654 struct tcp_zerocopy_receive zc;
3655 int err;
3656
3657 if (get_user(len, optlen))
3658 return -EFAULT;
3659 if (len != sizeof(zc))
3660 return -EINVAL;
3661 if (copy_from_user(&zc, optval, len))
3662 return -EFAULT;
3663 lock_sock(sk);
3664 err = tcp_zerocopy_receive(sk, &zc);
3665 release_sock(sk);
3666 if (!err && copy_to_user(optval, &zc, len))
3667 err = -EFAULT;
3668 return err;
3669 }
3670#endif
3671 default:
3672 return -ENOPROTOOPT;
3673 }
3674
3675 if (put_user(len, optlen))
3676 return -EFAULT;
3677 if (copy_to_user(optval, &val, len))
3678 return -EFAULT;
3679 return 0;
3680}
3681
3682int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
3683 int __user *optlen)
3684{
3685 struct inet_connection_sock *icsk = inet_csk(sk);
3686
3687 if (level != SOL_TCP)
3688 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
3689 optval, optlen);
3690 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
3691}
3692EXPORT_SYMBOL(tcp_getsockopt);
3693
3694#ifdef CONFIG_COMPAT
3695int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
3696 char __user *optval, int __user *optlen)
3697{
3698 if (level != SOL_TCP)
3699 return inet_csk_compat_getsockopt(sk, level, optname,
3700 optval, optlen);
3701 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
3702}
3703EXPORT_SYMBOL(compat_tcp_getsockopt);
3704#endif
3705
3706#ifdef CONFIG_TCP_MD5SIG
3707static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
3708static DEFINE_MUTEX(tcp_md5sig_mutex);
3709static bool tcp_md5sig_pool_populated = false;
3710
3711static void __tcp_alloc_md5sig_pool(void)
3712{
3713 struct crypto_ahash *hash;
3714 int cpu;
3715
3716 hash = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
3717 if (IS_ERR(hash))
3718 return;
3719
3720 for_each_possible_cpu(cpu) {
3721 void *scratch = per_cpu(tcp_md5sig_pool, cpu).scratch;
3722 struct ahash_request *req;
3723
3724 if (!scratch) {
3725 scratch = kmalloc_node(sizeof(union tcp_md5sum_block) +
3726 sizeof(struct tcphdr),
3727 GFP_KERNEL,
3728 cpu_to_node(cpu));
3729 if (!scratch)
3730 return;
3731 per_cpu(tcp_md5sig_pool, cpu).scratch = scratch;
3732 }
3733 if (per_cpu(tcp_md5sig_pool, cpu).md5_req)
3734 continue;
3735
3736 req = ahash_request_alloc(hash, GFP_KERNEL);
3737 if (!req)
3738 return;
3739
3740 ahash_request_set_callback(req, 0, NULL, NULL);
3741
3742 per_cpu(tcp_md5sig_pool, cpu).md5_req = req;
3743 }
3744 /* before setting tcp_md5sig_pool_populated, we must commit all writes
3745 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
3746 */
3747 smp_wmb();
3748 tcp_md5sig_pool_populated = true;
3749}
3750
3751bool tcp_alloc_md5sig_pool(void)
3752{
3753 if (unlikely(!tcp_md5sig_pool_populated)) {
3754 mutex_lock(&tcp_md5sig_mutex);
3755
3756 if (!tcp_md5sig_pool_populated) {
3757 __tcp_alloc_md5sig_pool();
3758 if (tcp_md5sig_pool_populated)
3759 static_branch_inc(&tcp_md5_needed);
3760 }
3761
3762 mutex_unlock(&tcp_md5sig_mutex);
3763 }
3764 return tcp_md5sig_pool_populated;
3765}
3766EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
3767
3768
3769/**
3770 * tcp_get_md5sig_pool - get md5sig_pool for this user
3771 *
3772 * We use percpu structure, so if we succeed, we exit with preemption
3773 * and BH disabled, to make sure another thread or softirq handling
3774 * wont try to get same context.
3775 */
3776struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
3777{
3778 local_bh_disable();
3779
3780 if (tcp_md5sig_pool_populated) {
3781 /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
3782 smp_rmb();
3783 return this_cpu_ptr(&tcp_md5sig_pool);
3784 }
3785 local_bh_enable();
3786 return NULL;
3787}
3788EXPORT_SYMBOL(tcp_get_md5sig_pool);
3789
3790int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3791 const struct sk_buff *skb, unsigned int header_len)
3792{
3793 struct scatterlist sg;
3794 const struct tcphdr *tp = tcp_hdr(skb);
3795 struct ahash_request *req = hp->md5_req;
3796 unsigned int i;
3797 const unsigned int head_data_len = skb_headlen(skb) > header_len ?
3798 skb_headlen(skb) - header_len : 0;
3799 const struct skb_shared_info *shi = skb_shinfo(skb);
3800 struct sk_buff *frag_iter;
3801
3802 sg_init_table(&sg, 1);
3803
3804 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3805 ahash_request_set_crypt(req, &sg, NULL, head_data_len);
3806 if (crypto_ahash_update(req))
3807 return 1;
3808
3809 for (i = 0; i < shi->nr_frags; ++i) {
3810 const skb_frag_t *f = &shi->frags[i];
3811 unsigned int offset = skb_frag_off(f);
3812 struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
3813
3814 sg_set_page(&sg, page, skb_frag_size(f),
3815 offset_in_page(offset));
3816 ahash_request_set_crypt(req, &sg, NULL, skb_frag_size(f));
3817 if (crypto_ahash_update(req))
3818 return 1;
3819 }
3820
3821 skb_walk_frags(skb, frag_iter)
3822 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3823 return 1;
3824
3825 return 0;
3826}
3827EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3828
3829int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3830{
3831 struct scatterlist sg;
3832
3833 sg_init_one(&sg, key->key, key->keylen);
3834 ahash_request_set_crypt(hp->md5_req, &sg, NULL, key->keylen);
3835 return crypto_ahash_update(hp->md5_req);
3836}
3837EXPORT_SYMBOL(tcp_md5_hash_key);
3838
3839#endif
3840
3841void tcp_done(struct sock *sk)
3842{
3843 struct request_sock *req;
3844
3845 /* We might be called with a new socket, after
3846 * inet_csk_prepare_forced_close() has been called
3847 * so we can not use lockdep_sock_is_held(sk)
3848 */
3849 req = rcu_dereference_protected(tcp_sk(sk)->fastopen_rsk, 1);
3850
3851 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3852 TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3853
3854 tcp_set_state(sk, TCP_CLOSE);
3855 tcp_clear_xmit_timers(sk);
3856 if (req)
3857 reqsk_fastopen_remove(sk, req, false);
3858
3859 sk->sk_shutdown = SHUTDOWN_MASK;
3860
3861 if (!sock_flag(sk, SOCK_DEAD))
3862 sk->sk_state_change(sk);
3863 else
3864 inet_csk_destroy_sock(sk);
3865}
3866EXPORT_SYMBOL_GPL(tcp_done);
3867
3868int tcp_abort(struct sock *sk, int err)
3869{
3870 if (!sk_fullsock(sk)) {
3871 if (sk->sk_state == TCP_NEW_SYN_RECV) {
3872 struct request_sock *req = inet_reqsk(sk);
3873
3874 local_bh_disable();
3875 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
3876 local_bh_enable();
3877 return 0;
3878 }
3879 return -EOPNOTSUPP;
3880 }
3881
3882 /* Don't race with userspace socket closes such as tcp_close. */
3883 lock_sock(sk);
3884
3885 if (sk->sk_state == TCP_LISTEN) {
3886 tcp_set_state(sk, TCP_CLOSE);
3887 inet_csk_listen_stop(sk);
3888 }
3889
3890 /* Don't race with BH socket closes such as inet_csk_listen_stop. */
3891 local_bh_disable();
3892 bh_lock_sock(sk);
3893
3894 if (!sock_flag(sk, SOCK_DEAD)) {
3895 sk->sk_err = err;
3896 /* This barrier is coupled with smp_rmb() in tcp_poll() */
3897 smp_wmb();
3898 sk->sk_error_report(sk);
3899 if (tcp_need_reset(sk->sk_state))
3900 tcp_send_active_reset(sk, GFP_ATOMIC);
3901 tcp_done(sk);
3902 }
3903
3904 bh_unlock_sock(sk);
3905 local_bh_enable();
3906 tcp_write_queue_purge(sk);
3907 release_sock(sk);
3908 return 0;
3909}
3910EXPORT_SYMBOL_GPL(tcp_abort);
3911
3912extern struct tcp_congestion_ops tcp_reno;
3913
3914static __initdata unsigned long thash_entries;
3915static int __init set_thash_entries(char *str)
3916{
3917 ssize_t ret;
3918
3919 if (!str)
3920 return 0;
3921
3922 ret = kstrtoul(str, 0, &thash_entries);
3923 if (ret)
3924 return 0;
3925
3926 return 1;
3927}
3928__setup("thash_entries=", set_thash_entries);
3929
3930static void __init tcp_init_mem(void)
3931{
3932 unsigned long limit = nr_free_buffer_pages() / 16;
3933
3934 limit = max(limit, 128UL);
3935 sysctl_tcp_mem[0] = limit / 4 * 3; /* 4.68 % */
3936 sysctl_tcp_mem[1] = limit; /* 6.25 % */
3937 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; /* 9.37 % */
3938}
3939
3940void __init tcp_init(void)
3941{
3942 int max_rshare, max_wshare, cnt;
3943 unsigned long limit;
3944 unsigned int i;
3945
3946 BUILD_BUG_ON(TCP_MIN_SND_MSS <= MAX_TCP_OPTION_SPACE);
3947 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) >
3948 FIELD_SIZEOF(struct sk_buff, cb));
3949
3950 percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
3951 percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3952 inet_hashinfo_init(&tcp_hashinfo);
3953 inet_hashinfo2_init(&tcp_hashinfo, "tcp_listen_portaddr_hash",
3954 thash_entries, 21, /* one slot per 2 MB*/
3955 0, 64 * 1024);
3956 tcp_hashinfo.bind_bucket_cachep =
3957 kmem_cache_create("tcp_bind_bucket",
3958 sizeof(struct inet_bind_bucket), 0,
3959 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3960
3961 /* Size and allocate the main established and bind bucket
3962 * hash tables.
3963 *
3964 * The methodology is similar to that of the buffer cache.
3965 */
3966 tcp_hashinfo.ehash =
3967 alloc_large_system_hash("TCP established",
3968 sizeof(struct inet_ehash_bucket),
3969 thash_entries,
3970 17, /* one slot per 128 KB of memory */
3971 0,
3972 NULL,
3973 &tcp_hashinfo.ehash_mask,
3974 0,
3975 thash_entries ? 0 : 512 * 1024);
3976 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3977 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3978
3979 if (inet_ehash_locks_alloc(&tcp_hashinfo))
3980 panic("TCP: failed to alloc ehash_locks");
3981 tcp_hashinfo.bhash =
3982 alloc_large_system_hash("TCP bind",
3983 sizeof(struct inet_bind_hashbucket),
3984 tcp_hashinfo.ehash_mask + 1,
3985 17, /* one slot per 128 KB of memory */
3986 0,
3987 &tcp_hashinfo.bhash_size,
3988 NULL,
3989 0,
3990 64 * 1024);
3991 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3992 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3993 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3994 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3995 }
3996
3997
3998 cnt = tcp_hashinfo.ehash_mask + 1;
3999 sysctl_tcp_max_orphans = cnt / 2;
4000
4001 tcp_init_mem();
4002 /* Set per-socket limits to no more than 1/128 the pressure threshold */
4003 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
4004 max_wshare = min(4UL*1024*1024, limit);
4005 max_rshare = min(6UL*1024*1024, limit);
4006
4007 init_net.ipv4.sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
4008 init_net.ipv4.sysctl_tcp_wmem[1] = 16*1024;
4009 init_net.ipv4.sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
4010
4011 init_net.ipv4.sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
4012 init_net.ipv4.sysctl_tcp_rmem[1] = 131072;
4013 init_net.ipv4.sysctl_tcp_rmem[2] = max(131072, max_rshare);
4014
4015 pr_info("Hash tables configured (established %u bind %u)\n",
4016 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
4017
4018 tcp_v4_init();
4019 tcp_metrics_init();
4020 BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
4021 tcp_tasklet_init();
4022}