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.
6 * Implementation of the Transmission Control Protocol(TCP).
8 * Version: $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Mark Evans, <evansmp@uhura.aston.ac.uk>
13 * Corey Minyard <wf-rch!minyard@relay.EU.net>
14 * Florian La Roche, <flla@stud.uni-sb.de>
15 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
16 * Linus Torvalds, <torvalds@cs.helsinki.fi>
17 * Alan Cox, <gw4pts@gw4pts.ampr.org>
18 * Matthew Dillon, <dillon@apollo.west.oic.com>
19 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
20 * Jorge Cwik, <jorge@laser.satlink.net>
23 * Alan Cox : Numerous verify_area() calls
24 * Alan Cox : Set the ACK bit on a reset
25 * Alan Cox : Stopped it crashing if it closed while
26 * sk->inuse=1 and was trying to connect
28 * Alan Cox : All icmp error handling was broken
29 * pointers passed where wrong and the
30 * socket was looked up backwards. Nobody
31 * tested any icmp error code obviously.
32 * Alan Cox : tcp_err() now handled properly. It
33 * wakes people on errors. poll
34 * behaves and the icmp error race
35 * has gone by moving it into sock.c
36 * Alan Cox : tcp_send_reset() fixed to work for
37 * everything not just packets for
39 * Alan Cox : tcp option processing.
40 * Alan Cox : Reset tweaked (still not 100%) [Had
42 * Herp Rosmanith : More reset fixes
43 * Alan Cox : No longer acks invalid rst frames.
44 * Acking any kind of RST is right out.
45 * Alan Cox : Sets an ignore me flag on an rst
46 * receive otherwise odd bits of prattle
48 * Alan Cox : Fixed another acking RST frame bug.
49 * Should stop LAN workplace lockups.
50 * Alan Cox : Some tidyups using the new skb list
52 * Alan Cox : sk->keepopen now seems to work
53 * Alan Cox : Pulls options out correctly on accepts
54 * Alan Cox : Fixed assorted sk->rqueue->next errors
55 * Alan Cox : PSH doesn't end a TCP read. Switched a
57 * Alan Cox : Tidied tcp_data to avoid a potential
59 * Alan Cox : Added some better commenting, as the
60 * tcp is hard to follow
61 * Alan Cox : Removed incorrect check for 20 * psh
62 * Michael O'Reilly : ack < copied bug fix.
63 * Johannes Stille : Misc tcp fixes (not all in yet).
64 * Alan Cox : FIN with no memory -> CRASH
65 * Alan Cox : Added socket option proto entries.
66 * Also added awareness of them to accept.
67 * Alan Cox : Added TCP options (SOL_TCP)
68 * Alan Cox : Switched wakeup calls to callbacks,
69 * so the kernel can layer network
71 * Alan Cox : Use ip_tos/ip_ttl settings.
72 * Alan Cox : Handle FIN (more) properly (we hope).
73 * Alan Cox : RST frames sent on unsynchronised
75 * Alan Cox : Put in missing check for SYN bit.
76 * Alan Cox : Added tcp_select_window() aka NET2E
77 * window non shrink trick.
78 * Alan Cox : Added a couple of small NET2E timer
80 * Charles Hedrick : TCP fixes
81 * Toomas Tamm : TCP window fixes
82 * Alan Cox : Small URG fix to rlogin ^C ack fight
83 * Charles Hedrick : Rewrote most of it to actually work
84 * Linus : Rewrote tcp_read() and URG handling
86 * Gerhard Koerting: Fixed some missing timer handling
87 * Matthew Dillon : Reworked TCP machine states as per RFC
88 * Gerhard Koerting: PC/TCP workarounds
89 * Adam Caldwell : Assorted timer/timing errors
90 * Matthew Dillon : Fixed another RST bug
91 * Alan Cox : Move to kernel side addressing changes.
92 * Alan Cox : Beginning work on TCP fastpathing
94 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
95 * Alan Cox : TCP fast path debugging
96 * Alan Cox : Window clamping
97 * Michael Riepe : Bug in tcp_check()
98 * Matt Dillon : More TCP improvements and RST bug fixes
99 * Matt Dillon : Yet more small nasties remove from the
100 * TCP code (Be very nice to this man if
101 * tcp finally works 100%) 8)
102 * Alan Cox : BSD accept semantics.
103 * Alan Cox : Reset on closedown bug.
104 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
105 * Michael Pall : Handle poll() after URG properly in
107 * Michael Pall : Undo the last fix in tcp_read_urg()
108 * (multi URG PUSH broke rlogin).
109 * Michael Pall : Fix the multi URG PUSH problem in
110 * tcp_readable(), poll() after URG
112 * Michael Pall : recv(...,MSG_OOB) never blocks in the
114 * Alan Cox : Changed the semantics of sk->socket to
115 * fix a race and a signal problem with
116 * accept() and async I/O.
117 * Alan Cox : Relaxed the rules on tcp_sendto().
118 * Yury Shevchuk : Really fixed accept() blocking problem.
119 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
120 * clients/servers which listen in on
122 * Alan Cox : Cleaned the above up and shrank it to
123 * a sensible code size.
124 * Alan Cox : Self connect lockup fix.
125 * Alan Cox : No connect to multicast.
126 * Ross Biro : Close unaccepted children on master
128 * Alan Cox : Reset tracing code.
129 * Alan Cox : Spurious resets on shutdown.
130 * Alan Cox : Giant 15 minute/60 second timer error
131 * Alan Cox : Small whoops in polling before an
133 * Alan Cox : Kept the state trace facility since
134 * it's handy for debugging.
135 * Alan Cox : More reset handler fixes.
136 * Alan Cox : Started rewriting the code based on
137 * the RFC's for other useful protocol
138 * references see: Comer, KA9Q NOS, and
139 * for a reference on the difference
140 * between specifications and how BSD
141 * works see the 4.4lite source.
142 * A.N.Kuznetsov : Don't time wait on completion of tidy
144 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
145 * Linus Torvalds : Fixed BSD port reuse to work first syn
146 * Alan Cox : Reimplemented timers as per the RFC
147 * and using multiple timers for sanity.
148 * Alan Cox : Small bug fixes, and a lot of new
150 * Alan Cox : Fixed dual reader crash by locking
151 * the buffers (much like datagram.c)
152 * Alan Cox : Fixed stuck sockets in probe. A probe
153 * now gets fed up of retrying without
154 * (even a no space) answer.
155 * Alan Cox : Extracted closing code better
156 * Alan Cox : Fixed the closing state machine to
158 * Alan Cox : More 'per spec' fixes.
159 * Jorge Cwik : Even faster checksumming.
160 * Alan Cox : tcp_data() doesn't ack illegal PSH
161 * only frames. At least one pc tcp stack
163 * Alan Cox : Cache last socket.
164 * Alan Cox : Per route irtt.
165 * Matt Day : poll()->select() match BSD precisely on error
166 * Alan Cox : New buffers
167 * Marc Tamsky : Various sk->prot->retransmits and
168 * sk->retransmits misupdating fixed.
169 * Fixed tcp_write_timeout: stuck close,
170 * and TCP syn retries gets used now.
171 * Mark Yarvis : In tcp_read_wakeup(), don't send an
172 * ack if state is TCP_CLOSED.
173 * Alan Cox : Look up device on a retransmit - routes may
174 * change. Doesn't yet cope with MSS shrink right
176 * Marc Tamsky : Closing in closing fixes.
177 * Mike Shaver : RFC1122 verifications.
178 * Alan Cox : rcv_saddr errors.
179 * Alan Cox : Block double connect().
180 * Alan Cox : Small hooks for enSKIP.
181 * Alexey Kuznetsov: Path MTU discovery.
182 * Alan Cox : Support soft errors.
183 * Alan Cox : Fix MTU discovery pathological case
184 * when the remote claims no mtu!
185 * Marc Tamsky : TCP_CLOSE fix.
186 * Colin (G3TNE) : Send a reset on syn ack replies in
187 * window but wrong (fixes NT lpd problems)
188 * Pedro Roque : Better TCP window handling, delayed ack.
189 * Joerg Reuter : No modification of locked buffers in
190 * tcp_do_retransmit()
191 * Eric Schenk : Changed receiver side silly window
192 * avoidance algorithm to BSD style
193 * algorithm. This doubles throughput
194 * against machines running Solaris,
195 * and seems to result in general
197 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
198 * Willy Konynenberg : Transparent proxying support.
199 * Mike McLagan : Routing by source
200 * Keith Owens : Do proper merging with partial SKB's in
201 * tcp_do_sendmsg to avoid burstiness.
202 * Eric Schenk : Fix fast close down bug with
203 * shutdown() followed by close().
204 * Andi Kleen : Make poll agree with SIGIO
205 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
206 * lingertime == 0 (RFC 793 ABORT Call)
207 * Hirokazu Takahashi : Use copy_from_user() instead of
208 * csum_and_copy_from_user() if possible.
210 * This program is free software; you can redistribute it and/or
211 * modify it under the terms of the GNU General Public License
212 * as published by the Free Software Foundation; either version
213 * 2 of the License, or(at your option) any later version.
215 * Description of States:
217 * TCP_SYN_SENT sent a connection request, waiting for ack
219 * TCP_SYN_RECV received a connection request, sent ack,
220 * waiting for final ack in three-way handshake.
222 * TCP_ESTABLISHED connection established
224 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
225 * transmission of remaining buffered data
227 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
230 * TCP_CLOSING both sides have shutdown but we still have
231 * data we have to finish sending
233 * TCP_TIME_WAIT timeout to catch resent junk before entering
234 * closed, can only be entered from FIN_WAIT2
235 * or CLOSING. Required because the other end
236 * may not have gotten our last ACK causing it
237 * to retransmit the data packet (which we ignore)
239 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
240 * us to finish writing our data and to shutdown
241 * (we have to close() to move on to LAST_ACK)
243 * TCP_LAST_ACK out side has shutdown after remote has
244 * shutdown. There may still be data in our
245 * buffer that we have to finish sending
247 * TCP_CLOSE socket is finished
250 #include <linux/kernel.h>
251 #include <linux/module.h>
252 #include <linux/types.h>
253 #include <linux/fcntl.h>
254 #include <linux/poll.h>
255 #include <linux/init.h>
256 #include <linux/fs.h>
257 #include <linux/skbuff.h>
258 #include <linux/splice.h>
259 #include <linux/net.h>
260 #include <linux/socket.h>
261 #include <linux/random.h>
262 #include <linux/bootmem.h>
263 #include <linux/cache.h>
264 #include <linux/err.h>
265 #include <linux/crypto.h>
267 #include <net/icmp.h>
269 #include <net/xfrm.h>
271 #include <net/netdma.h>
272 #include <net/sock.h>
274 #include <asm/uaccess.h>
275 #include <asm/ioctls.h>
277 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
279 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly;
281 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
283 EXPORT_SYMBOL_GPL(tcp_orphan_count);
285 int sysctl_tcp_mem[3] __read_mostly;
286 int sysctl_tcp_wmem[3] __read_mostly;
287 int sysctl_tcp_rmem[3] __read_mostly;
289 EXPORT_SYMBOL(sysctl_tcp_mem);
290 EXPORT_SYMBOL(sysctl_tcp_rmem);
291 EXPORT_SYMBOL(sysctl_tcp_wmem);
293 atomic_t tcp_memory_allocated; /* Current allocated memory. */
294 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
296 EXPORT_SYMBOL(tcp_memory_allocated);
297 EXPORT_SYMBOL(tcp_sockets_allocated);
302 struct tcp_splice_state {
303 struct pipe_inode_info *pipe;
309 * Pressure flag: try to collapse.
310 * Technical note: it is used by multiple contexts non atomically.
311 * All the sk_stream_mem_schedule() is of this nature: accounting
312 * is strict, actions are advisory and have some latency.
314 int tcp_memory_pressure __read_mostly;
316 EXPORT_SYMBOL(tcp_memory_pressure);
318 void tcp_enter_memory_pressure(void)
320 if (!tcp_memory_pressure) {
321 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
322 tcp_memory_pressure = 1;
326 EXPORT_SYMBOL(tcp_enter_memory_pressure);
329 * Wait for a TCP event.
331 * Note that we don't need to lock the socket, as the upper poll layers
332 * take care of normal races (between the test and the event) and we don't
333 * go look at any of the socket buffers directly.
335 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
338 struct sock *sk = sock->sk;
339 struct tcp_sock *tp = tcp_sk(sk);
341 poll_wait(file, sk->sk_sleep, wait);
342 if (sk->sk_state == TCP_LISTEN)
343 return inet_csk_listen_poll(sk);
345 /* Socket is not locked. We are protected from async events
346 by poll logic and correct handling of state changes
347 made by another threads is impossible in any case.
355 * POLLHUP is certainly not done right. But poll() doesn't
356 * have a notion of HUP in just one direction, and for a
357 * socket the read side is more interesting.
359 * Some poll() documentation says that POLLHUP is incompatible
360 * with the POLLOUT/POLLWR flags, so somebody should check this
361 * all. But careful, it tends to be safer to return too many
362 * bits than too few, and you can easily break real applications
363 * if you don't tell them that something has hung up!
367 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
368 * our fs/select.c). It means that after we received EOF,
369 * poll always returns immediately, making impossible poll() on write()
370 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
371 * if and only if shutdown has been made in both directions.
372 * Actually, it is interesting to look how Solaris and DUX
373 * solve this dilemma. I would prefer, if PULLHUP were maskable,
374 * then we could set it on SND_SHUTDOWN. BTW examples given
375 * in Stevens' books assume exactly this behaviour, it explains
376 * why PULLHUP is incompatible with POLLOUT. --ANK
378 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
379 * blocking on fresh not-connected or disconnected socket. --ANK
381 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
383 if (sk->sk_shutdown & RCV_SHUTDOWN)
384 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
387 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
388 /* Potential race condition. If read of tp below will
389 * escape above sk->sk_state, we can be illegally awaken
390 * in SYN_* states. */
391 if ((tp->rcv_nxt != tp->copied_seq) &&
392 (tp->urg_seq != tp->copied_seq ||
393 tp->rcv_nxt != tp->copied_seq + 1 ||
394 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
395 mask |= POLLIN | POLLRDNORM;
397 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
398 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
399 mask |= POLLOUT | POLLWRNORM;
400 } else { /* send SIGIO later */
401 set_bit(SOCK_ASYNC_NOSPACE,
402 &sk->sk_socket->flags);
403 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
405 /* Race breaker. If space is freed after
406 * wspace test but before the flags are set,
407 * IO signal will be lost.
409 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
410 mask |= POLLOUT | POLLWRNORM;
414 if (tp->urg_data & TCP_URG_VALID)
420 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
422 struct tcp_sock *tp = tcp_sk(sk);
427 if (sk->sk_state == TCP_LISTEN)
431 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
433 else if (sock_flag(sk, SOCK_URGINLINE) ||
435 before(tp->urg_seq, tp->copied_seq) ||
436 !before(tp->urg_seq, tp->rcv_nxt)) {
437 answ = tp->rcv_nxt - tp->copied_seq;
439 /* Subtract 1, if FIN is in queue. */
440 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
442 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin;
444 answ = tp->urg_seq - tp->copied_seq;
448 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
451 if (sk->sk_state == TCP_LISTEN)
454 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
457 answ = tp->write_seq - tp->snd_una;
463 return put_user(answ, (int __user *)arg);
466 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
468 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
469 tp->pushed_seq = tp->write_seq;
472 static inline int forced_push(struct tcp_sock *tp)
474 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
477 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
479 struct tcp_sock *tp = tcp_sk(sk);
480 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
483 tcb->seq = tcb->end_seq = tp->write_seq;
484 tcb->flags = TCPCB_FLAG_ACK;
486 skb_header_release(skb);
487 tcp_add_write_queue_tail(sk, skb);
488 sk_charge_skb(sk, skb);
489 if (tp->nonagle & TCP_NAGLE_PUSH)
490 tp->nonagle &= ~TCP_NAGLE_PUSH;
493 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
496 if (flags & MSG_OOB) {
498 tp->snd_up = tp->write_seq;
499 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
503 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
506 struct tcp_sock *tp = tcp_sk(sk);
508 if (tcp_send_head(sk)) {
509 struct sk_buff *skb = tcp_write_queue_tail(sk);
510 if (!(flags & MSG_MORE) || forced_push(tp))
511 tcp_mark_push(tp, skb);
512 tcp_mark_urg(tp, flags, skb);
513 __tcp_push_pending_frames(sk, mss_now,
514 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
518 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
519 unsigned int offset, size_t len)
521 struct tcp_splice_state *tss = rd_desc->arg.data;
523 return skb_splice_bits(skb, offset, tss->pipe, tss->len, tss->flags);
526 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
528 /* Store TCP splice context information in read_descriptor_t. */
529 read_descriptor_t rd_desc = {
533 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
537 * tcp_splice_read - splice data from TCP socket to a pipe
538 * @sock: socket to splice from
539 * @ppos: position (not valid)
540 * @pipe: pipe to splice to
541 * @len: number of bytes to splice
542 * @flags: splice modifier flags
545 * Will read pages from given socket and fill them into a pipe.
548 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
549 struct pipe_inode_info *pipe, size_t len,
552 struct sock *sk = sock->sk;
553 struct tcp_splice_state tss = {
563 * We can't seek on a socket input
572 timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK);
574 ret = __tcp_splice_read(sk, &tss);
580 if (flags & SPLICE_F_NONBLOCK) {
584 if (sock_flag(sk, SOCK_DONE))
587 ret = sock_error(sk);
590 if (sk->sk_shutdown & RCV_SHUTDOWN)
592 if (sk->sk_state == TCP_CLOSE) {
594 * This occurs when user tries to read
595 * from never connected socket.
597 if (!sock_flag(sk, SOCK_DONE))
605 sk_wait_data(sk, &timeo);
606 if (signal_pending(current)) {
607 ret = sock_intr_errno(timeo);
618 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
619 (sk->sk_shutdown & RCV_SHUTDOWN) || !timeo ||
620 signal_pending(current))
632 struct sk_buff *sk_stream_alloc_pskb(struct sock *sk,
633 int size, int mem, gfp_t gfp)
637 /* The TCP header must be at least 32-bit aligned. */
638 size = ALIGN(size, 4);
640 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
642 skb->truesize += mem;
643 if (sk_stream_wmem_schedule(sk, skb->truesize)) {
645 * Make sure that we have exactly size bytes
646 * available to the caller, no more, no less.
648 skb_reserve(skb, skb_tailroom(skb) - size);
653 sk->sk_prot->enter_memory_pressure();
654 sk_stream_moderate_sndbuf(sk);
659 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
660 size_t psize, int flags)
662 struct tcp_sock *tp = tcp_sk(sk);
663 int mss_now, size_goal;
666 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
668 /* Wait for a connection to finish. */
669 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
670 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
673 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
675 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
676 size_goal = tp->xmit_size_goal;
680 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
684 struct sk_buff *skb = tcp_write_queue_tail(sk);
685 struct page *page = pages[poffset / PAGE_SIZE];
686 int copy, i, can_coalesce;
687 int offset = poffset % PAGE_SIZE;
688 int size = min_t(size_t, psize, PAGE_SIZE - offset);
690 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
692 if (!sk_stream_memory_free(sk))
693 goto wait_for_sndbuf;
695 skb = sk_stream_alloc_pskb(sk, 0, 0,
698 goto wait_for_memory;
707 i = skb_shinfo(skb)->nr_frags;
708 can_coalesce = skb_can_coalesce(skb, i, page, offset);
709 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
710 tcp_mark_push(tp, skb);
713 if (!sk_stream_wmem_schedule(sk, copy))
714 goto wait_for_memory;
717 skb_shinfo(skb)->frags[i - 1].size += copy;
720 skb_fill_page_desc(skb, i, page, offset, copy);
724 skb->data_len += copy;
725 skb->truesize += copy;
726 sk->sk_wmem_queued += copy;
727 sk->sk_forward_alloc -= copy;
728 skb->ip_summed = CHECKSUM_PARTIAL;
729 tp->write_seq += copy;
730 TCP_SKB_CB(skb)->end_seq += copy;
731 skb_shinfo(skb)->gso_segs = 0;
734 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
738 if (!(psize -= copy))
741 if (skb->len < mss_now || (flags & MSG_OOB))
744 if (forced_push(tp)) {
745 tcp_mark_push(tp, skb);
746 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
747 } else if (skb == tcp_send_head(sk))
748 tcp_push_one(sk, mss_now);
752 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
755 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
757 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
760 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
761 size_goal = tp->xmit_size_goal;
766 tcp_push(sk, flags, mss_now, tp->nonagle);
773 return sk_stream_error(sk, flags, err);
776 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
777 size_t size, int flags)
780 struct sock *sk = sock->sk;
782 if (!(sk->sk_route_caps & NETIF_F_SG) ||
783 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
784 return sock_no_sendpage(sock, page, offset, size, flags);
788 res = do_tcp_sendpages(sk, &page, offset, size, flags);
794 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
795 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
797 static inline int select_size(struct sock *sk)
799 struct tcp_sock *tp = tcp_sk(sk);
800 int tmp = tp->mss_cache;
802 if (sk->sk_route_caps & NETIF_F_SG) {
806 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
808 if (tmp >= pgbreak &&
809 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
817 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
820 struct sock *sk = sock->sk;
822 struct tcp_sock *tp = tcp_sk(sk);
825 int mss_now, size_goal;
832 flags = msg->msg_flags;
833 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
835 /* Wait for a connection to finish. */
836 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
837 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
840 /* This should be in poll */
841 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
843 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
844 size_goal = tp->xmit_size_goal;
846 /* Ok commence sending. */
847 iovlen = msg->msg_iovlen;
852 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
855 while (--iovlen >= 0) {
856 int seglen = iov->iov_len;
857 unsigned char __user *from = iov->iov_base;
864 skb = tcp_write_queue_tail(sk);
866 if (!tcp_send_head(sk) ||
867 (copy = size_goal - skb->len) <= 0) {
870 /* Allocate new segment. If the interface is SG,
871 * allocate skb fitting to single page.
873 if (!sk_stream_memory_free(sk))
874 goto wait_for_sndbuf;
876 skb = sk_stream_alloc_pskb(sk, select_size(sk),
877 0, sk->sk_allocation);
879 goto wait_for_memory;
882 * Check whether we can use HW checksum.
884 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
885 skb->ip_summed = CHECKSUM_PARTIAL;
891 /* Try to append data to the end of skb. */
895 /* Where to copy to? */
896 if (skb_tailroom(skb) > 0) {
897 /* We have some space in skb head. Superb! */
898 if (copy > skb_tailroom(skb))
899 copy = skb_tailroom(skb);
900 if ((err = skb_add_data(skb, from, copy)) != 0)
904 int i = skb_shinfo(skb)->nr_frags;
905 struct page *page = TCP_PAGE(sk);
906 int off = TCP_OFF(sk);
908 if (skb_can_coalesce(skb, i, page, off) &&
910 /* We can extend the last page
913 } else if (i == MAX_SKB_FRAGS ||
915 !(sk->sk_route_caps & NETIF_F_SG))) {
916 /* Need to add new fragment and cannot
917 * do this because interface is non-SG,
918 * or because all the page slots are
920 tcp_mark_push(tp, skb);
923 if (off == PAGE_SIZE) {
925 TCP_PAGE(sk) = page = NULL;
931 if (copy > PAGE_SIZE - off)
932 copy = PAGE_SIZE - off;
934 if (!sk_stream_wmem_schedule(sk, copy))
935 goto wait_for_memory;
938 /* Allocate new cache page. */
939 if (!(page = sk_stream_alloc_page(sk)))
940 goto wait_for_memory;
943 /* Time to copy data. We are close to
945 err = skb_copy_to_page(sk, from, skb, page,
948 /* If this page was new, give it to the
949 * socket so it does not get leaked.
958 /* Update the skb. */
960 skb_shinfo(skb)->frags[i - 1].size +=
963 skb_fill_page_desc(skb, i, page, off, copy);
966 } else if (off + copy < PAGE_SIZE) {
972 TCP_OFF(sk) = off + copy;
976 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
978 tp->write_seq += copy;
979 TCP_SKB_CB(skb)->end_seq += copy;
980 skb_shinfo(skb)->gso_segs = 0;
984 if ((seglen -= copy) == 0 && iovlen == 0)
987 if (skb->len < mss_now || (flags & MSG_OOB))
990 if (forced_push(tp)) {
991 tcp_mark_push(tp, skb);
992 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
993 } else if (skb == tcp_send_head(sk))
994 tcp_push_one(sk, mss_now);
998 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1001 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1003 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1006 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
1007 size_goal = tp->xmit_size_goal;
1013 tcp_push(sk, flags, mss_now, tp->nonagle);
1014 TCP_CHECK_TIMER(sk);
1020 tcp_unlink_write_queue(skb, sk);
1021 /* It is the one place in all of TCP, except connection
1022 * reset, where we can be unlinking the send_head.
1024 tcp_check_send_head(sk, skb);
1025 sk_stream_free_skb(sk, skb);
1032 err = sk_stream_error(sk, flags, err);
1033 TCP_CHECK_TIMER(sk);
1039 * Handle reading urgent data. BSD has very simple semantics for
1040 * this, no blocking and very strange errors 8)
1043 static int tcp_recv_urg(struct sock *sk, long timeo,
1044 struct msghdr *msg, int len, int flags,
1047 struct tcp_sock *tp = tcp_sk(sk);
1049 /* No URG data to read. */
1050 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1051 tp->urg_data == TCP_URG_READ)
1052 return -EINVAL; /* Yes this is right ! */
1054 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1057 if (tp->urg_data & TCP_URG_VALID) {
1059 char c = tp->urg_data;
1061 if (!(flags & MSG_PEEK))
1062 tp->urg_data = TCP_URG_READ;
1064 /* Read urgent data. */
1065 msg->msg_flags |= MSG_OOB;
1068 if (!(flags & MSG_TRUNC))
1069 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1072 msg->msg_flags |= MSG_TRUNC;
1074 return err ? -EFAULT : len;
1077 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1080 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1081 * the available implementations agree in this case:
1082 * this call should never block, independent of the
1083 * blocking state of the socket.
1084 * Mike <pall@rz.uni-karlsruhe.de>
1089 /* Clean up the receive buffer for full frames taken by the user,
1090 * then send an ACK if necessary. COPIED is the number of bytes
1091 * tcp_recvmsg has given to the user so far, it speeds up the
1092 * calculation of whether or not we must ACK for the sake of
1095 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1097 struct tcp_sock *tp = tcp_sk(sk);
1098 int time_to_ack = 0;
1101 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1103 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
1106 if (inet_csk_ack_scheduled(sk)) {
1107 const struct inet_connection_sock *icsk = inet_csk(sk);
1108 /* Delayed ACKs frequently hit locked sockets during bulk
1110 if (icsk->icsk_ack.blocked ||
1111 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1112 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1114 * If this read emptied read buffer, we send ACK, if
1115 * connection is not bidirectional, user drained
1116 * receive buffer and there was a small segment
1120 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1121 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1122 !icsk->icsk_ack.pingpong)) &&
1123 !atomic_read(&sk->sk_rmem_alloc)))
1127 /* We send an ACK if we can now advertise a non-zero window
1128 * which has been raised "significantly".
1130 * Even if window raised up to infinity, do not send window open ACK
1131 * in states, where we will not receive more. It is useless.
1133 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1134 __u32 rcv_window_now = tcp_receive_window(tp);
1136 /* Optimize, __tcp_select_window() is not cheap. */
1137 if (2*rcv_window_now <= tp->window_clamp) {
1138 __u32 new_window = __tcp_select_window(sk);
1140 /* Send ACK now, if this read freed lots of space
1141 * in our buffer. Certainly, new_window is new window.
1142 * We can advertise it now, if it is not less than current one.
1143 * "Lots" means "at least twice" here.
1145 if (new_window && new_window >= 2 * rcv_window_now)
1153 static void tcp_prequeue_process(struct sock *sk)
1155 struct sk_buff *skb;
1156 struct tcp_sock *tp = tcp_sk(sk);
1158 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
1160 /* RX process wants to run with disabled BHs, though it is not
1163 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1164 sk->sk_backlog_rcv(sk, skb);
1167 /* Clear memory counter. */
1168 tp->ucopy.memory = 0;
1171 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1173 struct sk_buff *skb;
1176 skb_queue_walk(&sk->sk_receive_queue, skb) {
1177 offset = seq - TCP_SKB_CB(skb)->seq;
1178 if (tcp_hdr(skb)->syn)
1180 if (offset < skb->len || tcp_hdr(skb)->fin) {
1189 * This routine provides an alternative to tcp_recvmsg() for routines
1190 * that would like to handle copying from skbuffs directly in 'sendfile'
1193 * - It is assumed that the socket was locked by the caller.
1194 * - The routine does not block.
1195 * - At present, there is no support for reading OOB data
1196 * or for 'peeking' the socket using this routine
1197 * (although both would be easy to implement).
1199 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1200 sk_read_actor_t recv_actor)
1202 struct sk_buff *skb;
1203 struct tcp_sock *tp = tcp_sk(sk);
1204 u32 seq = tp->copied_seq;
1208 if (sk->sk_state == TCP_LISTEN)
1210 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1211 if (offset < skb->len) {
1214 len = skb->len - offset;
1215 /* Stop reading if we hit a patch of urgent data */
1217 u32 urg_offset = tp->urg_seq - seq;
1218 if (urg_offset < len)
1223 used = recv_actor(desc, skb, offset, len);
1228 } else if (used <= len) {
1233 if (offset != skb->len)
1236 if (tcp_hdr(skb)->fin) {
1237 sk_eat_skb(sk, skb, 0);
1241 sk_eat_skb(sk, skb, 0);
1245 tp->copied_seq = seq;
1247 tcp_rcv_space_adjust(sk);
1249 /* Clean up data we have read: This will do ACK frames. */
1251 tcp_cleanup_rbuf(sk, copied);
1256 * This routine copies from a sock struct into the user buffer.
1258 * Technical note: in 2.3 we work on _locked_ socket, so that
1259 * tricks with *seq access order and skb->users are not required.
1260 * Probably, code can be easily improved even more.
1263 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1264 size_t len, int nonblock, int flags, int *addr_len)
1266 struct tcp_sock *tp = tcp_sk(sk);
1272 int target; /* Read at least this many bytes */
1274 struct task_struct *user_recv = NULL;
1275 int copied_early = 0;
1276 struct sk_buff *skb;
1280 TCP_CHECK_TIMER(sk);
1283 if (sk->sk_state == TCP_LISTEN)
1286 timeo = sock_rcvtimeo(sk, nonblock);
1288 /* Urgent data needs to be handled specially. */
1289 if (flags & MSG_OOB)
1292 seq = &tp->copied_seq;
1293 if (flags & MSG_PEEK) {
1294 peek_seq = tp->copied_seq;
1298 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1300 #ifdef CONFIG_NET_DMA
1301 tp->ucopy.dma_chan = NULL;
1303 skb = skb_peek_tail(&sk->sk_receive_queue);
1308 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1309 if ((available < target) &&
1310 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1311 !sysctl_tcp_low_latency &&
1312 __get_cpu_var(softnet_data).net_dma) {
1313 preempt_enable_no_resched();
1314 tp->ucopy.pinned_list =
1315 dma_pin_iovec_pages(msg->msg_iov, len);
1317 preempt_enable_no_resched();
1325 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1326 if (tp->urg_data && tp->urg_seq == *seq) {
1329 if (signal_pending(current)) {
1330 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1335 /* Next get a buffer. */
1337 skb = skb_peek(&sk->sk_receive_queue);
1342 /* Now that we have two receive queues this
1345 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1346 printk(KERN_INFO "recvmsg bug: copied %X "
1347 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1350 offset = *seq - TCP_SKB_CB(skb)->seq;
1351 if (tcp_hdr(skb)->syn)
1353 if (offset < skb->len)
1355 if (tcp_hdr(skb)->fin)
1357 BUG_TRAP(flags & MSG_PEEK);
1359 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1361 /* Well, if we have backlog, try to process it now yet. */
1363 if (copied >= target && !sk->sk_backlog.tail)
1368 sk->sk_state == TCP_CLOSE ||
1369 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1371 signal_pending(current) ||
1375 if (sock_flag(sk, SOCK_DONE))
1379 copied = sock_error(sk);
1383 if (sk->sk_shutdown & RCV_SHUTDOWN)
1386 if (sk->sk_state == TCP_CLOSE) {
1387 if (!sock_flag(sk, SOCK_DONE)) {
1388 /* This occurs when user tries to read
1389 * from never connected socket.
1402 if (signal_pending(current)) {
1403 copied = sock_intr_errno(timeo);
1408 tcp_cleanup_rbuf(sk, copied);
1410 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1411 /* Install new reader */
1412 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1413 user_recv = current;
1414 tp->ucopy.task = user_recv;
1415 tp->ucopy.iov = msg->msg_iov;
1418 tp->ucopy.len = len;
1420 BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1421 (flags & (MSG_PEEK | MSG_TRUNC)));
1423 /* Ugly... If prequeue is not empty, we have to
1424 * process it before releasing socket, otherwise
1425 * order will be broken at second iteration.
1426 * More elegant solution is required!!!
1428 * Look: we have the following (pseudo)queues:
1430 * 1. packets in flight
1435 * Each queue can be processed only if the next ones
1436 * are empty. At this point we have empty receive_queue.
1437 * But prequeue _can_ be not empty after 2nd iteration,
1438 * when we jumped to start of loop because backlog
1439 * processing added something to receive_queue.
1440 * We cannot release_sock(), because backlog contains
1441 * packets arrived _after_ prequeued ones.
1443 * Shortly, algorithm is clear --- to process all
1444 * the queues in order. We could make it more directly,
1445 * requeueing packets from backlog to prequeue, if
1446 * is not empty. It is more elegant, but eats cycles,
1449 if (!skb_queue_empty(&tp->ucopy.prequeue))
1452 /* __ Set realtime policy in scheduler __ */
1455 if (copied >= target) {
1456 /* Do not sleep, just process backlog. */
1460 sk_wait_data(sk, &timeo);
1462 #ifdef CONFIG_NET_DMA
1463 tp->ucopy.wakeup = 0;
1469 /* __ Restore normal policy in scheduler __ */
1471 if ((chunk = len - tp->ucopy.len) != 0) {
1472 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1477 if (tp->rcv_nxt == tp->copied_seq &&
1478 !skb_queue_empty(&tp->ucopy.prequeue)) {
1480 tcp_prequeue_process(sk);
1482 if ((chunk = len - tp->ucopy.len) != 0) {
1483 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1489 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1490 if (net_ratelimit())
1491 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1492 current->comm, task_pid_nr(current));
1493 peek_seq = tp->copied_seq;
1498 /* Ok so how much can we use? */
1499 used = skb->len - offset;
1503 /* Do we have urgent data here? */
1505 u32 urg_offset = tp->urg_seq - *seq;
1506 if (urg_offset < used) {
1508 if (!sock_flag(sk, SOCK_URGINLINE)) {
1520 if (!(flags & MSG_TRUNC)) {
1521 #ifdef CONFIG_NET_DMA
1522 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1523 tp->ucopy.dma_chan = get_softnet_dma();
1525 if (tp->ucopy.dma_chan) {
1526 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1527 tp->ucopy.dma_chan, skb, offset,
1529 tp->ucopy.pinned_list);
1531 if (tp->ucopy.dma_cookie < 0) {
1533 printk(KERN_ALERT "dma_cookie < 0\n");
1535 /* Exception. Bailout! */
1540 if ((offset + used) == skb->len)
1546 err = skb_copy_datagram_iovec(skb, offset,
1547 msg->msg_iov, used);
1549 /* Exception. Bailout! */
1561 tcp_rcv_space_adjust(sk);
1564 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1566 tcp_fast_path_check(sk);
1568 if (used + offset < skb->len)
1571 if (tcp_hdr(skb)->fin)
1573 if (!(flags & MSG_PEEK)) {
1574 sk_eat_skb(sk, skb, copied_early);
1580 /* Process the FIN. */
1582 if (!(flags & MSG_PEEK)) {
1583 sk_eat_skb(sk, skb, copied_early);
1590 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1593 tp->ucopy.len = copied > 0 ? len : 0;
1595 tcp_prequeue_process(sk);
1597 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1598 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1604 tp->ucopy.task = NULL;
1608 #ifdef CONFIG_NET_DMA
1609 if (tp->ucopy.dma_chan) {
1610 dma_cookie_t done, used;
1612 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1614 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1615 tp->ucopy.dma_cookie, &done,
1616 &used) == DMA_IN_PROGRESS) {
1617 /* do partial cleanup of sk_async_wait_queue */
1618 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1619 (dma_async_is_complete(skb->dma_cookie, done,
1620 used) == DMA_SUCCESS)) {
1621 __skb_dequeue(&sk->sk_async_wait_queue);
1626 /* Safe to free early-copied skbs now */
1627 __skb_queue_purge(&sk->sk_async_wait_queue);
1628 dma_chan_put(tp->ucopy.dma_chan);
1629 tp->ucopy.dma_chan = NULL;
1631 if (tp->ucopy.pinned_list) {
1632 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1633 tp->ucopy.pinned_list = NULL;
1637 /* According to UNIX98, msg_name/msg_namelen are ignored
1638 * on connected socket. I was just happy when found this 8) --ANK
1641 /* Clean up data we have read: This will do ACK frames. */
1642 tcp_cleanup_rbuf(sk, copied);
1644 TCP_CHECK_TIMER(sk);
1649 TCP_CHECK_TIMER(sk);
1654 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1659 * State processing on a close. This implements the state shift for
1660 * sending our FIN frame. Note that we only send a FIN for some
1661 * states. A shutdown() may have already sent the FIN, or we may be
1665 static const unsigned char new_state[16] = {
1666 /* current state: new state: action: */
1667 /* (Invalid) */ TCP_CLOSE,
1668 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1669 /* TCP_SYN_SENT */ TCP_CLOSE,
1670 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1671 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1672 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1673 /* TCP_TIME_WAIT */ TCP_CLOSE,
1674 /* TCP_CLOSE */ TCP_CLOSE,
1675 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1676 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1677 /* TCP_LISTEN */ TCP_CLOSE,
1678 /* TCP_CLOSING */ TCP_CLOSING,
1681 static int tcp_close_state(struct sock *sk)
1683 int next = (int)new_state[sk->sk_state];
1684 int ns = next & TCP_STATE_MASK;
1686 tcp_set_state(sk, ns);
1688 return next & TCP_ACTION_FIN;
1692 * Shutdown the sending side of a connection. Much like close except
1693 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1696 void tcp_shutdown(struct sock *sk, int how)
1698 /* We need to grab some memory, and put together a FIN,
1699 * and then put it into the queue to be sent.
1700 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1702 if (!(how & SEND_SHUTDOWN))
1705 /* If we've already sent a FIN, or it's a closed state, skip this. */
1706 if ((1 << sk->sk_state) &
1707 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1708 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1709 /* Clear out any half completed packets. FIN if needed. */
1710 if (tcp_close_state(sk))
1715 void tcp_close(struct sock *sk, long timeout)
1717 struct sk_buff *skb;
1718 int data_was_unread = 0;
1722 sk->sk_shutdown = SHUTDOWN_MASK;
1724 if (sk->sk_state == TCP_LISTEN) {
1725 tcp_set_state(sk, TCP_CLOSE);
1728 inet_csk_listen_stop(sk);
1730 goto adjudge_to_death;
1733 /* We need to flush the recv. buffs. We do this only on the
1734 * descriptor close, not protocol-sourced closes, because the
1735 * reader process may not have drained the data yet!
1737 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1738 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1740 data_was_unread += len;
1744 sk_stream_mem_reclaim(sk);
1746 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1747 * data was lost. To witness the awful effects of the old behavior of
1748 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1749 * GET in an FTP client, suspend the process, wait for the client to
1750 * advertise a zero window, then kill -9 the FTP client, wheee...
1751 * Note: timeout is always zero in such a case.
1753 if (data_was_unread) {
1754 /* Unread data was tossed, zap the connection. */
1755 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1756 tcp_set_state(sk, TCP_CLOSE);
1757 tcp_send_active_reset(sk, GFP_KERNEL);
1758 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1759 /* Check zero linger _after_ checking for unread data. */
1760 sk->sk_prot->disconnect(sk, 0);
1761 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1762 } else if (tcp_close_state(sk)) {
1763 /* We FIN if the application ate all the data before
1764 * zapping the connection.
1767 /* RED-PEN. Formally speaking, we have broken TCP state
1768 * machine. State transitions:
1770 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1771 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1772 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1774 * are legal only when FIN has been sent (i.e. in window),
1775 * rather than queued out of window. Purists blame.
1777 * F.e. "RFC state" is ESTABLISHED,
1778 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1780 * The visible declinations are that sometimes
1781 * we enter time-wait state, when it is not required really
1782 * (harmless), do not send active resets, when they are
1783 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1784 * they look as CLOSING or LAST_ACK for Linux)
1785 * Probably, I missed some more holelets.
1791 sk_stream_wait_close(sk, timeout);
1794 state = sk->sk_state;
1797 atomic_inc(sk->sk_prot->orphan_count);
1799 /* It is the last release_sock in its life. It will remove backlog. */
1803 /* Now socket is owned by kernel and we acquire BH lock
1804 to finish close. No need to check for user refs.
1808 BUG_TRAP(!sock_owned_by_user(sk));
1810 /* Have we already been destroyed by a softirq or backlog? */
1811 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1814 /* This is a (useful) BSD violating of the RFC. There is a
1815 * problem with TCP as specified in that the other end could
1816 * keep a socket open forever with no application left this end.
1817 * We use a 3 minute timeout (about the same as BSD) then kill
1818 * our end. If they send after that then tough - BUT: long enough
1819 * that we won't make the old 4*rto = almost no time - whoops
1822 * Nope, it was not mistake. It is really desired behaviour
1823 * f.e. on http servers, when such sockets are useless, but
1824 * consume significant resources. Let's do it with special
1825 * linger2 option. --ANK
1828 if (sk->sk_state == TCP_FIN_WAIT2) {
1829 struct tcp_sock *tp = tcp_sk(sk);
1830 if (tp->linger2 < 0) {
1831 tcp_set_state(sk, TCP_CLOSE);
1832 tcp_send_active_reset(sk, GFP_ATOMIC);
1833 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1835 const int tmo = tcp_fin_time(sk);
1837 if (tmo > TCP_TIMEWAIT_LEN) {
1838 inet_csk_reset_keepalive_timer(sk,
1839 tmo - TCP_TIMEWAIT_LEN);
1841 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1846 if (sk->sk_state != TCP_CLOSE) {
1847 sk_stream_mem_reclaim(sk);
1848 if (tcp_too_many_orphans(sk,
1849 atomic_read(sk->sk_prot->orphan_count))) {
1850 if (net_ratelimit())
1851 printk(KERN_INFO "TCP: too many of orphaned "
1853 tcp_set_state(sk, TCP_CLOSE);
1854 tcp_send_active_reset(sk, GFP_ATOMIC);
1855 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1859 if (sk->sk_state == TCP_CLOSE)
1860 inet_csk_destroy_sock(sk);
1861 /* Otherwise, socket is reprieved until protocol close. */
1869 /* These states need RST on ABORT according to RFC793 */
1871 static inline int tcp_need_reset(int state)
1873 return (1 << state) &
1874 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1875 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1878 int tcp_disconnect(struct sock *sk, int flags)
1880 struct inet_sock *inet = inet_sk(sk);
1881 struct inet_connection_sock *icsk = inet_csk(sk);
1882 struct tcp_sock *tp = tcp_sk(sk);
1884 int old_state = sk->sk_state;
1886 if (old_state != TCP_CLOSE)
1887 tcp_set_state(sk, TCP_CLOSE);
1889 /* ABORT function of RFC793 */
1890 if (old_state == TCP_LISTEN) {
1891 inet_csk_listen_stop(sk);
1892 } else if (tcp_need_reset(old_state) ||
1893 (tp->snd_nxt != tp->write_seq &&
1894 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1895 /* The last check adjusts for discrepancy of Linux wrt. RFC
1898 tcp_send_active_reset(sk, gfp_any());
1899 sk->sk_err = ECONNRESET;
1900 } else if (old_state == TCP_SYN_SENT)
1901 sk->sk_err = ECONNRESET;
1903 tcp_clear_xmit_timers(sk);
1904 __skb_queue_purge(&sk->sk_receive_queue);
1905 tcp_write_queue_purge(sk);
1906 __skb_queue_purge(&tp->out_of_order_queue);
1907 #ifdef CONFIG_NET_DMA
1908 __skb_queue_purge(&sk->sk_async_wait_queue);
1913 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1914 inet_reset_saddr(sk);
1916 sk->sk_shutdown = 0;
1917 sock_reset_flag(sk, SOCK_DONE);
1919 if ((tp->write_seq += tp->max_window + 2) == 0)
1921 icsk->icsk_backoff = 0;
1923 icsk->icsk_probes_out = 0;
1924 tp->packets_out = 0;
1925 tp->snd_ssthresh = 0x7fffffff;
1926 tp->snd_cwnd_cnt = 0;
1927 tp->bytes_acked = 0;
1928 tcp_set_ca_state(sk, TCP_CA_Open);
1929 tcp_clear_retrans(tp);
1930 inet_csk_delack_init(sk);
1931 tcp_init_send_head(sk);
1932 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
1935 BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1937 sk->sk_error_report(sk);
1942 * Socket option code for TCP.
1944 static int do_tcp_setsockopt(struct sock *sk, int level,
1945 int optname, char __user *optval, int optlen)
1947 struct tcp_sock *tp = tcp_sk(sk);
1948 struct inet_connection_sock *icsk = inet_csk(sk);
1952 /* This is a string value all the others are int's */
1953 if (optname == TCP_CONGESTION) {
1954 char name[TCP_CA_NAME_MAX];
1959 val = strncpy_from_user(name, optval,
1960 min(TCP_CA_NAME_MAX-1, optlen));
1966 err = tcp_set_congestion_control(sk, name);
1971 if (optlen < sizeof(int))
1974 if (get_user(val, (int __user *)optval))
1981 /* Values greater than interface MTU won't take effect. However
1982 * at the point when this call is done we typically don't yet
1983 * know which interface is going to be used */
1984 if (val < 8 || val > MAX_TCP_WINDOW) {
1988 tp->rx_opt.user_mss = val;
1993 /* TCP_NODELAY is weaker than TCP_CORK, so that
1994 * this option on corked socket is remembered, but
1995 * it is not activated until cork is cleared.
1997 * However, when TCP_NODELAY is set we make
1998 * an explicit push, which overrides even TCP_CORK
1999 * for currently queued segments.
2001 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2002 tcp_push_pending_frames(sk);
2004 tp->nonagle &= ~TCP_NAGLE_OFF;
2009 /* When set indicates to always queue non-full frames.
2010 * Later the user clears this option and we transmit
2011 * any pending partial frames in the queue. This is
2012 * meant to be used alongside sendfile() to get properly
2013 * filled frames when the user (for example) must write
2014 * out headers with a write() call first and then use
2015 * sendfile to send out the data parts.
2017 * TCP_CORK can be set together with TCP_NODELAY and it is
2018 * stronger than TCP_NODELAY.
2021 tp->nonagle |= TCP_NAGLE_CORK;
2023 tp->nonagle &= ~TCP_NAGLE_CORK;
2024 if (tp->nonagle&TCP_NAGLE_OFF)
2025 tp->nonagle |= TCP_NAGLE_PUSH;
2026 tcp_push_pending_frames(sk);
2031 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2034 tp->keepalive_time = val * HZ;
2035 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2036 !((1 << sk->sk_state) &
2037 (TCPF_CLOSE | TCPF_LISTEN))) {
2038 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2039 if (tp->keepalive_time > elapsed)
2040 elapsed = tp->keepalive_time - elapsed;
2043 inet_csk_reset_keepalive_timer(sk, elapsed);
2048 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2051 tp->keepalive_intvl = val * HZ;
2054 if (val < 1 || val > MAX_TCP_KEEPCNT)
2057 tp->keepalive_probes = val;
2060 if (val < 1 || val > MAX_TCP_SYNCNT)
2063 icsk->icsk_syn_retries = val;
2069 else if (val > sysctl_tcp_fin_timeout / HZ)
2072 tp->linger2 = val * HZ;
2075 case TCP_DEFER_ACCEPT:
2076 icsk->icsk_accept_queue.rskq_defer_accept = 0;
2078 /* Translate value in seconds to number of
2080 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
2081 val > ((TCP_TIMEOUT_INIT / HZ) <<
2082 icsk->icsk_accept_queue.rskq_defer_accept))
2083 icsk->icsk_accept_queue.rskq_defer_accept++;
2084 icsk->icsk_accept_queue.rskq_defer_accept++;
2088 case TCP_WINDOW_CLAMP:
2090 if (sk->sk_state != TCP_CLOSE) {
2094 tp->window_clamp = 0;
2096 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2097 SOCK_MIN_RCVBUF / 2 : val;
2102 icsk->icsk_ack.pingpong = 1;
2104 icsk->icsk_ack.pingpong = 0;
2105 if ((1 << sk->sk_state) &
2106 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2107 inet_csk_ack_scheduled(sk)) {
2108 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2109 tcp_cleanup_rbuf(sk, 1);
2111 icsk->icsk_ack.pingpong = 1;
2116 #ifdef CONFIG_TCP_MD5SIG
2118 /* Read the IP->Key mappings from userspace */
2119 err = tp->af_specific->md5_parse(sk, optval, optlen);
2132 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2135 struct inet_connection_sock *icsk = inet_csk(sk);
2137 if (level != SOL_TCP)
2138 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2140 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2143 #ifdef CONFIG_COMPAT
2144 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2145 char __user *optval, int optlen)
2147 if (level != SOL_TCP)
2148 return inet_csk_compat_setsockopt(sk, level, optname,
2150 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2153 EXPORT_SYMBOL(compat_tcp_setsockopt);
2156 /* Return information about state of tcp endpoint in API format. */
2157 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2159 struct tcp_sock *tp = tcp_sk(sk);
2160 const struct inet_connection_sock *icsk = inet_csk(sk);
2161 u32 now = tcp_time_stamp;
2163 memset(info, 0, sizeof(*info));
2165 info->tcpi_state = sk->sk_state;
2166 info->tcpi_ca_state = icsk->icsk_ca_state;
2167 info->tcpi_retransmits = icsk->icsk_retransmits;
2168 info->tcpi_probes = icsk->icsk_probes_out;
2169 info->tcpi_backoff = icsk->icsk_backoff;
2171 if (tp->rx_opt.tstamp_ok)
2172 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2173 if (tcp_is_sack(tp))
2174 info->tcpi_options |= TCPI_OPT_SACK;
2175 if (tp->rx_opt.wscale_ok) {
2176 info->tcpi_options |= TCPI_OPT_WSCALE;
2177 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2178 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2181 if (tp->ecn_flags&TCP_ECN_OK)
2182 info->tcpi_options |= TCPI_OPT_ECN;
2184 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2185 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2186 info->tcpi_snd_mss = tp->mss_cache;
2187 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2189 if (sk->sk_state == TCP_LISTEN) {
2190 info->tcpi_unacked = sk->sk_ack_backlog;
2191 info->tcpi_sacked = sk->sk_max_ack_backlog;
2193 info->tcpi_unacked = tp->packets_out;
2194 info->tcpi_sacked = tp->sacked_out;
2196 info->tcpi_lost = tp->lost_out;
2197 info->tcpi_retrans = tp->retrans_out;
2198 info->tcpi_fackets = tp->fackets_out;
2200 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2201 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2202 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2204 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2205 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2206 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2207 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2208 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2209 info->tcpi_snd_cwnd = tp->snd_cwnd;
2210 info->tcpi_advmss = tp->advmss;
2211 info->tcpi_reordering = tp->reordering;
2213 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2214 info->tcpi_rcv_space = tp->rcvq_space.space;
2216 info->tcpi_total_retrans = tp->total_retrans;
2219 EXPORT_SYMBOL_GPL(tcp_get_info);
2221 static int do_tcp_getsockopt(struct sock *sk, int level,
2222 int optname, char __user *optval, int __user *optlen)
2224 struct inet_connection_sock *icsk = inet_csk(sk);
2225 struct tcp_sock *tp = tcp_sk(sk);
2228 if (get_user(len, optlen))
2231 len = min_t(unsigned int, len, sizeof(int));
2238 val = tp->mss_cache;
2239 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2240 val = tp->rx_opt.user_mss;
2243 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2246 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2249 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2252 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2255 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2258 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2263 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2265 case TCP_DEFER_ACCEPT:
2266 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2267 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2269 case TCP_WINDOW_CLAMP:
2270 val = tp->window_clamp;
2273 struct tcp_info info;
2275 if (get_user(len, optlen))
2278 tcp_get_info(sk, &info);
2280 len = min_t(unsigned int, len, sizeof(info));
2281 if (put_user(len, optlen))
2283 if (copy_to_user(optval, &info, len))
2288 val = !icsk->icsk_ack.pingpong;
2291 case TCP_CONGESTION:
2292 if (get_user(len, optlen))
2294 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2295 if (put_user(len, optlen))
2297 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2301 return -ENOPROTOOPT;
2304 if (put_user(len, optlen))
2306 if (copy_to_user(optval, &val, len))
2311 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2314 struct inet_connection_sock *icsk = inet_csk(sk);
2316 if (level != SOL_TCP)
2317 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2319 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2322 #ifdef CONFIG_COMPAT
2323 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2324 char __user *optval, int __user *optlen)
2326 if (level != SOL_TCP)
2327 return inet_csk_compat_getsockopt(sk, level, optname,
2329 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2332 EXPORT_SYMBOL(compat_tcp_getsockopt);
2335 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2337 struct sk_buff *segs = ERR_PTR(-EINVAL);
2342 unsigned int oldlen;
2345 if (!pskb_may_pull(skb, sizeof(*th)))
2349 thlen = th->doff * 4;
2350 if (thlen < sizeof(*th))
2353 if (!pskb_may_pull(skb, thlen))
2356 oldlen = (u16)~skb->len;
2357 __skb_pull(skb, thlen);
2359 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2360 /* Packet is from an untrusted source, reset gso_segs. */
2361 int type = skb_shinfo(skb)->gso_type;
2370 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2373 mss = skb_shinfo(skb)->gso_size;
2374 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2380 segs = skb_segment(skb, features);
2384 len = skb_shinfo(skb)->gso_size;
2385 delta = htonl(oldlen + (thlen + len));
2389 seq = ntohl(th->seq);
2392 th->fin = th->psh = 0;
2394 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2395 (__force u32)delta));
2396 if (skb->ip_summed != CHECKSUM_PARTIAL)
2398 csum_fold(csum_partial(skb_transport_header(skb),
2405 th->seq = htonl(seq);
2407 } while (skb->next);
2409 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2411 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2412 (__force u32)delta));
2413 if (skb->ip_summed != CHECKSUM_PARTIAL)
2414 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2420 EXPORT_SYMBOL(tcp_tso_segment);
2422 #ifdef CONFIG_TCP_MD5SIG
2423 static unsigned long tcp_md5sig_users;
2424 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2425 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2427 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2430 for_each_possible_cpu(cpu) {
2431 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2433 if (p->md5_desc.tfm)
2434 crypto_free_hash(p->md5_desc.tfm);
2442 void tcp_free_md5sig_pool(void)
2444 struct tcp_md5sig_pool **pool = NULL;
2446 spin_lock_bh(&tcp_md5sig_pool_lock);
2447 if (--tcp_md5sig_users == 0) {
2448 pool = tcp_md5sig_pool;
2449 tcp_md5sig_pool = NULL;
2451 spin_unlock_bh(&tcp_md5sig_pool_lock);
2453 __tcp_free_md5sig_pool(pool);
2456 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2458 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
2461 struct tcp_md5sig_pool **pool;
2463 pool = alloc_percpu(struct tcp_md5sig_pool *);
2467 for_each_possible_cpu(cpu) {
2468 struct tcp_md5sig_pool *p;
2469 struct crypto_hash *hash;
2471 p = kzalloc(sizeof(*p), GFP_KERNEL);
2474 *per_cpu_ptr(pool, cpu) = p;
2476 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2477 if (!hash || IS_ERR(hash))
2480 p->md5_desc.tfm = hash;
2484 __tcp_free_md5sig_pool(pool);
2488 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
2490 struct tcp_md5sig_pool **pool;
2494 spin_lock_bh(&tcp_md5sig_pool_lock);
2495 pool = tcp_md5sig_pool;
2496 if (tcp_md5sig_users++ == 0) {
2498 spin_unlock_bh(&tcp_md5sig_pool_lock);
2501 spin_unlock_bh(&tcp_md5sig_pool_lock);
2505 spin_unlock_bh(&tcp_md5sig_pool_lock);
2508 /* we cannot hold spinlock here because this may sleep. */
2509 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
2510 spin_lock_bh(&tcp_md5sig_pool_lock);
2513 spin_unlock_bh(&tcp_md5sig_pool_lock);
2516 pool = tcp_md5sig_pool;
2518 /* oops, it has already been assigned. */
2519 spin_unlock_bh(&tcp_md5sig_pool_lock);
2520 __tcp_free_md5sig_pool(p);
2522 tcp_md5sig_pool = pool = p;
2523 spin_unlock_bh(&tcp_md5sig_pool_lock);
2529 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2531 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2533 struct tcp_md5sig_pool **p;
2534 spin_lock_bh(&tcp_md5sig_pool_lock);
2535 p = tcp_md5sig_pool;
2538 spin_unlock_bh(&tcp_md5sig_pool_lock);
2539 return (p ? *per_cpu_ptr(p, cpu) : NULL);
2542 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2544 void __tcp_put_md5sig_pool(void)
2546 tcp_free_md5sig_pool();
2549 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2552 void tcp_done(struct sock *sk)
2554 if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2555 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
2557 tcp_set_state(sk, TCP_CLOSE);
2558 tcp_clear_xmit_timers(sk);
2560 sk->sk_shutdown = SHUTDOWN_MASK;
2562 if (!sock_flag(sk, SOCK_DEAD))
2563 sk->sk_state_change(sk);
2565 inet_csk_destroy_sock(sk);
2567 EXPORT_SYMBOL_GPL(tcp_done);
2569 extern void __skb_cb_too_small_for_tcp(int, int);
2570 extern struct tcp_congestion_ops tcp_reno;
2572 static __initdata unsigned long thash_entries;
2573 static int __init set_thash_entries(char *str)
2577 thash_entries = simple_strtoul(str, &str, 0);
2580 __setup("thash_entries=", set_thash_entries);
2582 void __init tcp_init(void)
2584 struct sk_buff *skb = NULL;
2585 unsigned long limit;
2586 int order, i, max_share;
2588 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2589 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2592 tcp_hashinfo.bind_bucket_cachep =
2593 kmem_cache_create("tcp_bind_bucket",
2594 sizeof(struct inet_bind_bucket), 0,
2595 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2597 /* Size and allocate the main established and bind bucket
2600 * The methodology is similar to that of the buffer cache.
2602 tcp_hashinfo.ehash =
2603 alloc_large_system_hash("TCP established",
2604 sizeof(struct inet_ehash_bucket),
2606 (num_physpages >= 128 * 1024) ?
2609 &tcp_hashinfo.ehash_size,
2611 thash_entries ? 0 : 512 * 1024);
2612 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2613 for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2614 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2615 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain);
2617 if (inet_ehash_locks_alloc(&tcp_hashinfo))
2618 panic("TCP: failed to alloc ehash_locks");
2619 tcp_hashinfo.bhash =
2620 alloc_large_system_hash("TCP bind",
2621 sizeof(struct inet_bind_hashbucket),
2622 tcp_hashinfo.ehash_size,
2623 (num_physpages >= 128 * 1024) ?
2626 &tcp_hashinfo.bhash_size,
2629 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2630 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2631 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2632 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2635 /* Try to be a bit smarter and adjust defaults depending
2636 * on available memory.
2638 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2639 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2643 tcp_death_row.sysctl_max_tw_buckets = 180000;
2644 sysctl_tcp_max_orphans = 4096 << (order - 4);
2645 sysctl_max_syn_backlog = 1024;
2646 } else if (order < 3) {
2647 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2648 sysctl_tcp_max_orphans >>= (3 - order);
2649 sysctl_max_syn_backlog = 128;
2652 /* Set the pressure threshold to be a fraction of global memory that
2653 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2654 * memory, with a floor of 128 pages.
2656 limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
2657 limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
2658 limit = max(limit, 128UL);
2659 sysctl_tcp_mem[0] = limit / 4 * 3;
2660 sysctl_tcp_mem[1] = limit;
2661 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
2663 /* Set per-socket limits to no more than 1/128 the pressure threshold */
2664 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2665 max_share = min(4UL*1024*1024, limit);
2667 sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM;
2668 sysctl_tcp_wmem[1] = 16*1024;
2669 sysctl_tcp_wmem[2] = max(64*1024, max_share);
2671 sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM;
2672 sysctl_tcp_rmem[1] = 87380;
2673 sysctl_tcp_rmem[2] = max(87380, max_share);
2675 printk(KERN_INFO "TCP: Hash tables configured "
2676 "(established %d bind %d)\n",
2677 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
2679 tcp_register_congestion_control(&tcp_reno);
2682 EXPORT_SYMBOL(tcp_close);
2683 EXPORT_SYMBOL(tcp_disconnect);
2684 EXPORT_SYMBOL(tcp_getsockopt);
2685 EXPORT_SYMBOL(tcp_ioctl);
2686 EXPORT_SYMBOL(tcp_poll);
2687 EXPORT_SYMBOL(tcp_read_sock);
2688 EXPORT_SYMBOL(tcp_recvmsg);
2689 EXPORT_SYMBOL(tcp_sendmsg);
2690 EXPORT_SYMBOL(tcp_splice_read);
2691 EXPORT_SYMBOL(tcp_sendpage);
2692 EXPORT_SYMBOL(tcp_setsockopt);
2693 EXPORT_SYMBOL(tcp_shutdown);
2694 EXPORT_SYMBOL(tcp_statistics);