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).
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>
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
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
37 * Alan Cox : tcp option processing.
38 * Alan Cox : Reset tweaked (still not 100%) [Had
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
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
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
55 * Alan Cox : Tidied tcp_data to avoid a potential
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
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
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
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
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
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
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
110 * Michael Pall : recv(...,MSG_OOB) never blocks in the
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
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
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
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
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
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
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
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
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
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.
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.
213 * Description of States:
215 * TCP_SYN_SENT sent a connection request, waiting for ack
217 * TCP_SYN_RECV received a connection request, sent ack,
218 * waiting for final ack in three-way handshake.
220 * TCP_ESTABLISHED connection established
222 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
223 * transmission of remaining buffered data
225 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
228 * TCP_CLOSING both sides have shutdown but we still have
229 * data we have to finish sending
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)
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)
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
245 * TCP_CLOSE socket is finished
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>
268 #include <net/icmp.h>
270 #include <net/xfrm.h>
272 #include <net/netdma.h>
273 #include <net/sock.h>
275 #include <asm/uaccess.h>
276 #include <asm/ioctls.h>
278 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
280 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
282 EXPORT_SYMBOL_GPL(tcp_orphan_count);
284 int sysctl_tcp_mem[3] __read_mostly;
285 int sysctl_tcp_wmem[3] __read_mostly;
286 int sysctl_tcp_rmem[3] __read_mostly;
288 EXPORT_SYMBOL(sysctl_tcp_mem);
289 EXPORT_SYMBOL(sysctl_tcp_rmem);
290 EXPORT_SYMBOL(sysctl_tcp_wmem);
292 atomic_t tcp_memory_allocated; /* Current allocated memory. */
293 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
295 EXPORT_SYMBOL(tcp_memory_allocated);
296 EXPORT_SYMBOL(tcp_sockets_allocated);
301 struct tcp_splice_state {
302 struct pipe_inode_info *pipe;
308 * Pressure flag: try to collapse.
309 * Technical note: it is used by multiple contexts non atomically.
310 * All the __sk_mem_schedule() is of this nature: accounting
311 * is strict, actions are advisory and have some latency.
313 int tcp_memory_pressure __read_mostly;
315 EXPORT_SYMBOL(tcp_memory_pressure);
317 void tcp_enter_memory_pressure(struct sock *sk)
319 if (!tcp_memory_pressure) {
320 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
321 tcp_memory_pressure = 1;
325 EXPORT_SYMBOL(tcp_enter_memory_pressure);
328 * Wait for a TCP event.
330 * Note that we don't need to lock the socket, as the upper poll layers
331 * take care of normal races (between the test and the event) and we don't
332 * go look at any of the socket buffers directly.
334 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
337 struct sock *sk = sock->sk;
338 struct tcp_sock *tp = tcp_sk(sk);
340 poll_wait(file, sk->sk_sleep, wait);
341 if (sk->sk_state == TCP_LISTEN)
342 return inet_csk_listen_poll(sk);
344 /* Socket is not locked. We are protected from async events
345 * by poll logic and correct handling of state changes
346 * made by other threads is impossible in any case.
354 * POLLHUP is certainly not done right. But poll() doesn't
355 * have a notion of HUP in just one direction, and for a
356 * socket the read side is more interesting.
358 * Some poll() documentation says that POLLHUP is incompatible
359 * with the POLLOUT/POLLWR flags, so somebody should check this
360 * all. But careful, it tends to be safer to return too many
361 * bits than too few, and you can easily break real applications
362 * if you don't tell them that something has hung up!
366 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
367 * our fs/select.c). It means that after we received EOF,
368 * poll always returns immediately, making impossible poll() on write()
369 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
370 * if and only if shutdown has been made in both directions.
371 * Actually, it is interesting to look how Solaris and DUX
372 * solve this dilemma. I would prefer, if POLLHUP were maskable,
373 * then we could set it on SND_SHUTDOWN. BTW examples given
374 * in Stevens' books assume exactly this behaviour, it explains
375 * why POLLHUP is incompatible with POLLOUT. --ANK
377 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
378 * blocking on fresh not-connected or disconnected socket. --ANK
380 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
382 if (sk->sk_shutdown & RCV_SHUTDOWN)
383 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
386 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
387 int target = sock_rcvlowat(sk, 0, INT_MAX);
389 if (tp->urg_seq == tp->copied_seq &&
390 !sock_flag(sk, SOCK_URGINLINE) &&
394 /* Potential race condition. If read of tp below will
395 * escape above sk->sk_state, we can be illegally awaken
396 * in SYN_* states. */
397 if (tp->rcv_nxt - tp->copied_seq >= target)
398 mask |= POLLIN | POLLRDNORM;
400 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
401 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
402 mask |= POLLOUT | POLLWRNORM;
403 } else { /* send SIGIO later */
404 set_bit(SOCK_ASYNC_NOSPACE,
405 &sk->sk_socket->flags);
406 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
408 /* Race breaker. If space is freed after
409 * wspace test but before the flags are set,
410 * IO signal will be lost.
412 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
413 mask |= POLLOUT | POLLWRNORM;
417 if (tp->urg_data & TCP_URG_VALID)
423 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
425 struct tcp_sock *tp = tcp_sk(sk);
430 if (sk->sk_state == TCP_LISTEN)
434 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
436 else if (sock_flag(sk, SOCK_URGINLINE) ||
438 before(tp->urg_seq, tp->copied_seq) ||
439 !before(tp->urg_seq, tp->rcv_nxt)) {
440 answ = tp->rcv_nxt - tp->copied_seq;
442 /* Subtract 1, if FIN is in queue. */
443 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
445 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin;
447 answ = tp->urg_seq - tp->copied_seq;
451 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
454 if (sk->sk_state == TCP_LISTEN)
457 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
460 answ = tp->write_seq - tp->snd_una;
466 return put_user(answ, (int __user *)arg);
469 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
471 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
472 tp->pushed_seq = tp->write_seq;
475 static inline int forced_push(struct tcp_sock *tp)
477 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
480 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
482 struct tcp_sock *tp = tcp_sk(sk);
483 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
486 tcb->seq = tcb->end_seq = tp->write_seq;
487 tcb->flags = TCPCB_FLAG_ACK;
489 skb_header_release(skb);
490 tcp_add_write_queue_tail(sk, skb);
491 sk->sk_wmem_queued += skb->truesize;
492 sk_mem_charge(sk, skb->truesize);
493 if (tp->nonagle & TCP_NAGLE_PUSH)
494 tp->nonagle &= ~TCP_NAGLE_PUSH;
497 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
501 tp->snd_up = tp->write_seq;
504 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
507 struct tcp_sock *tp = tcp_sk(sk);
509 if (tcp_send_head(sk)) {
510 struct sk_buff *skb = tcp_write_queue_tail(sk);
511 if (!(flags & MSG_MORE) || forced_push(tp))
512 tcp_mark_push(tp, skb);
513 tcp_mark_urg(tp, flags, skb);
514 __tcp_push_pending_frames(sk, mss_now,
515 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
519 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
520 unsigned int offset, size_t len)
522 struct tcp_splice_state *tss = rd_desc->arg.data;
524 return skb_splice_bits(skb, offset, tss->pipe, tss->len, tss->flags);
527 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
529 /* Store TCP splice context information in read_descriptor_t. */
530 read_descriptor_t rd_desc = {
534 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
538 * tcp_splice_read - splice data from TCP socket to a pipe
539 * @sock: socket to splice from
540 * @ppos: position (not valid)
541 * @pipe: pipe to splice to
542 * @len: number of bytes to splice
543 * @flags: splice modifier flags
546 * Will read pages from given socket and fill them into a pipe.
549 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
550 struct pipe_inode_info *pipe, size_t len,
553 struct sock *sk = sock->sk;
554 struct tcp_splice_state tss = {
564 * We can't seek on a socket input
573 timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK);
575 ret = __tcp_splice_read(sk, &tss);
581 if (flags & SPLICE_F_NONBLOCK) {
585 if (sock_flag(sk, SOCK_DONE))
588 ret = sock_error(sk);
591 if (sk->sk_shutdown & RCV_SHUTDOWN)
593 if (sk->sk_state == TCP_CLOSE) {
595 * This occurs when user tries to read
596 * from never connected socket.
598 if (!sock_flag(sk, SOCK_DONE))
606 sk_wait_data(sk, &timeo);
607 if (signal_pending(current)) {
608 ret = sock_intr_errno(timeo);
619 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
620 (sk->sk_shutdown & RCV_SHUTDOWN) || !timeo ||
621 signal_pending(current))
633 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, 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 if (sk_wmem_schedule(sk, skb->truesize)) {
644 * Make sure that we have exactly size bytes
645 * available to the caller, no more, no less.
647 skb_reserve(skb, skb_tailroom(skb) - size);
652 sk->sk_prot->enter_memory_pressure(sk);
653 sk_stream_moderate_sndbuf(sk);
658 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
659 size_t psize, int flags)
661 struct tcp_sock *tp = tcp_sk(sk);
662 int mss_now, size_goal;
665 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
667 /* Wait for a connection to finish. */
668 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
669 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
672 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
674 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
675 size_goal = tp->xmit_size_goal;
679 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
683 struct sk_buff *skb = tcp_write_queue_tail(sk);
684 struct page *page = pages[poffset / PAGE_SIZE];
685 int copy, i, can_coalesce;
686 int offset = poffset % PAGE_SIZE;
687 int size = min_t(size_t, psize, PAGE_SIZE - offset);
689 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
691 if (!sk_stream_memory_free(sk))
692 goto wait_for_sndbuf;
694 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
696 goto wait_for_memory;
705 i = skb_shinfo(skb)->nr_frags;
706 can_coalesce = skb_can_coalesce(skb, i, page, offset);
707 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
708 tcp_mark_push(tp, skb);
711 if (!sk_wmem_schedule(sk, copy))
712 goto wait_for_memory;
715 skb_shinfo(skb)->frags[i - 1].size += copy;
718 skb_fill_page_desc(skb, i, page, offset, copy);
722 skb->data_len += copy;
723 skb->truesize += copy;
724 sk->sk_wmem_queued += copy;
725 sk_mem_charge(sk, copy);
726 skb->ip_summed = CHECKSUM_PARTIAL;
727 tp->write_seq += copy;
728 TCP_SKB_CB(skb)->end_seq += copy;
729 skb_shinfo(skb)->gso_segs = 0;
732 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
736 if (!(psize -= copy))
739 if (skb->len < size_goal || (flags & MSG_OOB))
742 if (forced_push(tp)) {
743 tcp_mark_push(tp, skb);
744 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
745 } else if (skb == tcp_send_head(sk))
746 tcp_push_one(sk, mss_now);
750 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
753 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
755 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
758 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
759 size_goal = tp->xmit_size_goal;
764 tcp_push(sk, flags, mss_now, tp->nonagle);
771 return sk_stream_error(sk, flags, err);
774 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
775 size_t size, int flags)
778 struct sock *sk = sock->sk;
780 if (!(sk->sk_route_caps & NETIF_F_SG) ||
781 !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
782 return sock_no_sendpage(sock, page, offset, size, flags);
786 res = do_tcp_sendpages(sk, &page, offset, size, flags);
792 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
793 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
795 static inline int select_size(struct sock *sk)
797 struct tcp_sock *tp = tcp_sk(sk);
798 int tmp = tp->mss_cache;
800 if (sk->sk_route_caps & NETIF_F_SG) {
804 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
806 if (tmp >= pgbreak &&
807 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
815 int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
818 struct sock *sk = sock->sk;
820 struct tcp_sock *tp = tcp_sk(sk);
823 int mss_now, size_goal;
830 flags = msg->msg_flags;
831 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
833 /* Wait for a connection to finish. */
834 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
835 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
838 /* This should be in poll */
839 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
841 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
842 size_goal = tp->xmit_size_goal;
844 /* Ok commence sending. */
845 iovlen = msg->msg_iovlen;
850 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
853 while (--iovlen >= 0) {
854 int seglen = iov->iov_len;
855 unsigned char __user *from = iov->iov_base;
862 skb = tcp_write_queue_tail(sk);
864 if (!tcp_send_head(sk) ||
865 (copy = size_goal - skb->len) <= 0) {
868 /* Allocate new segment. If the interface is SG,
869 * allocate skb fitting to single page.
871 if (!sk_stream_memory_free(sk))
872 goto wait_for_sndbuf;
874 skb = sk_stream_alloc_skb(sk, select_size(sk),
877 goto wait_for_memory;
880 * Check whether we can use HW checksum.
882 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
883 skb->ip_summed = CHECKSUM_PARTIAL;
889 /* Try to append data to the end of skb. */
893 /* Where to copy to? */
894 if (skb_tailroom(skb) > 0) {
895 /* We have some space in skb head. Superb! */
896 if (copy > skb_tailroom(skb))
897 copy = skb_tailroom(skb);
898 if ((err = skb_add_data(skb, from, copy)) != 0)
902 int i = skb_shinfo(skb)->nr_frags;
903 struct page *page = TCP_PAGE(sk);
904 int off = TCP_OFF(sk);
906 if (skb_can_coalesce(skb, i, page, off) &&
908 /* We can extend the last page
911 } else if (i == MAX_SKB_FRAGS ||
913 !(sk->sk_route_caps & NETIF_F_SG))) {
914 /* Need to add new fragment and cannot
915 * do this because interface is non-SG,
916 * or because all the page slots are
918 tcp_mark_push(tp, skb);
921 if (off == PAGE_SIZE) {
923 TCP_PAGE(sk) = page = NULL;
929 if (copy > PAGE_SIZE - off)
930 copy = PAGE_SIZE - off;
932 if (!sk_wmem_schedule(sk, copy))
933 goto wait_for_memory;
936 /* Allocate new cache page. */
937 if (!(page = sk_stream_alloc_page(sk)))
938 goto wait_for_memory;
941 /* Time to copy data. We are close to
943 err = skb_copy_to_page(sk, from, skb, page,
946 /* If this page was new, give it to the
947 * socket so it does not get leaked.
956 /* Update the skb. */
958 skb_shinfo(skb)->frags[i - 1].size +=
961 skb_fill_page_desc(skb, i, page, off, copy);
964 } else if (off + copy < PAGE_SIZE) {
970 TCP_OFF(sk) = off + copy;
974 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
976 tp->write_seq += copy;
977 TCP_SKB_CB(skb)->end_seq += copy;
978 skb_shinfo(skb)->gso_segs = 0;
982 if ((seglen -= copy) == 0 && iovlen == 0)
985 if (skb->len < size_goal || (flags & MSG_OOB))
988 if (forced_push(tp)) {
989 tcp_mark_push(tp, skb);
990 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
991 } else if (skb == tcp_send_head(sk))
992 tcp_push_one(sk, mss_now);
996 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
999 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1001 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1004 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
1005 size_goal = tp->xmit_size_goal;
1011 tcp_push(sk, flags, mss_now, tp->nonagle);
1012 TCP_CHECK_TIMER(sk);
1018 tcp_unlink_write_queue(skb, sk);
1019 /* It is the one place in all of TCP, except connection
1020 * reset, where we can be unlinking the send_head.
1022 tcp_check_send_head(sk, skb);
1023 sk_wmem_free_skb(sk, skb);
1030 err = sk_stream_error(sk, flags, err);
1031 TCP_CHECK_TIMER(sk);
1037 * Handle reading urgent data. BSD has very simple semantics for
1038 * this, no blocking and very strange errors 8)
1041 static int tcp_recv_urg(struct sock *sk, long timeo,
1042 struct msghdr *msg, int len, int flags,
1045 struct tcp_sock *tp = tcp_sk(sk);
1047 /* No URG data to read. */
1048 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1049 tp->urg_data == TCP_URG_READ)
1050 return -EINVAL; /* Yes this is right ! */
1052 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1055 if (tp->urg_data & TCP_URG_VALID) {
1057 char c = tp->urg_data;
1059 if (!(flags & MSG_PEEK))
1060 tp->urg_data = TCP_URG_READ;
1062 /* Read urgent data. */
1063 msg->msg_flags |= MSG_OOB;
1066 if (!(flags & MSG_TRUNC))
1067 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1070 msg->msg_flags |= MSG_TRUNC;
1072 return err ? -EFAULT : len;
1075 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1078 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1079 * the available implementations agree in this case:
1080 * this call should never block, independent of the
1081 * blocking state of the socket.
1082 * Mike <pall@rz.uni-karlsruhe.de>
1087 /* Clean up the receive buffer for full frames taken by the user,
1088 * then send an ACK if necessary. COPIED is the number of bytes
1089 * tcp_recvmsg has given to the user so far, it speeds up the
1090 * calculation of whether or not we must ACK for the sake of
1093 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1095 struct tcp_sock *tp = tcp_sk(sk);
1096 int time_to_ack = 0;
1099 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1101 WARN_ON(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
1104 if (inet_csk_ack_scheduled(sk)) {
1105 const struct inet_connection_sock *icsk = inet_csk(sk);
1106 /* Delayed ACKs frequently hit locked sockets during bulk
1108 if (icsk->icsk_ack.blocked ||
1109 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1110 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1112 * If this read emptied read buffer, we send ACK, if
1113 * connection is not bidirectional, user drained
1114 * receive buffer and there was a small segment
1118 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1119 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1120 !icsk->icsk_ack.pingpong)) &&
1121 !atomic_read(&sk->sk_rmem_alloc)))
1125 /* We send an ACK if we can now advertise a non-zero window
1126 * which has been raised "significantly".
1128 * Even if window raised up to infinity, do not send window open ACK
1129 * in states, where we will not receive more. It is useless.
1131 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1132 __u32 rcv_window_now = tcp_receive_window(tp);
1134 /* Optimize, __tcp_select_window() is not cheap. */
1135 if (2*rcv_window_now <= tp->window_clamp) {
1136 __u32 new_window = __tcp_select_window(sk);
1138 /* Send ACK now, if this read freed lots of space
1139 * in our buffer. Certainly, new_window is new window.
1140 * We can advertise it now, if it is not less than current one.
1141 * "Lots" means "at least twice" here.
1143 if (new_window && new_window >= 2 * rcv_window_now)
1151 static void tcp_prequeue_process(struct sock *sk)
1153 struct sk_buff *skb;
1154 struct tcp_sock *tp = tcp_sk(sk);
1156 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1158 /* RX process wants to run with disabled BHs, though it is not
1161 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1162 sk_backlog_rcv(sk, skb);
1165 /* Clear memory counter. */
1166 tp->ucopy.memory = 0;
1169 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1171 struct sk_buff *skb;
1174 skb_queue_walk(&sk->sk_receive_queue, skb) {
1175 offset = seq - TCP_SKB_CB(skb)->seq;
1176 if (tcp_hdr(skb)->syn)
1178 if (offset < skb->len || tcp_hdr(skb)->fin) {
1187 * This routine provides an alternative to tcp_recvmsg() for routines
1188 * that would like to handle copying from skbuffs directly in 'sendfile'
1191 * - It is assumed that the socket was locked by the caller.
1192 * - The routine does not block.
1193 * - At present, there is no support for reading OOB data
1194 * or for 'peeking' the socket using this routine
1195 * (although both would be easy to implement).
1197 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1198 sk_read_actor_t recv_actor)
1200 struct sk_buff *skb;
1201 struct tcp_sock *tp = tcp_sk(sk);
1202 u32 seq = tp->copied_seq;
1206 if (sk->sk_state == TCP_LISTEN)
1208 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1209 if (offset < skb->len) {
1213 len = skb->len - offset;
1214 /* Stop reading if we hit a patch of urgent data */
1216 u32 urg_offset = tp->urg_seq - seq;
1217 if (urg_offset < len)
1222 used = recv_actor(desc, skb, offset, len);
1227 } else if (used <= len) {
1233 * If recv_actor drops the lock (e.g. TCP splice
1234 * receive) the skb pointer might be invalid when
1235 * getting here: tcp_collapse might have deleted it
1236 * while aggregating skbs from the socket queue.
1238 skb = tcp_recv_skb(sk, seq-1, &offset);
1239 if (!skb || (offset+1 != skb->len))
1242 if (tcp_hdr(skb)->fin) {
1243 sk_eat_skb(sk, skb, 0);
1247 sk_eat_skb(sk, skb, 0);
1251 tp->copied_seq = seq;
1253 tcp_rcv_space_adjust(sk);
1255 /* Clean up data we have read: This will do ACK frames. */
1257 tcp_cleanup_rbuf(sk, copied);
1262 * This routine copies from a sock struct into the user buffer.
1264 * Technical note: in 2.3 we work on _locked_ socket, so that
1265 * tricks with *seq access order and skb->users are not required.
1266 * Probably, code can be easily improved even more.
1269 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1270 size_t len, int nonblock, int flags, int *addr_len)
1272 struct tcp_sock *tp = tcp_sk(sk);
1278 int target; /* Read at least this many bytes */
1280 struct task_struct *user_recv = NULL;
1281 int copied_early = 0;
1282 struct sk_buff *skb;
1286 TCP_CHECK_TIMER(sk);
1289 if (sk->sk_state == TCP_LISTEN)
1292 timeo = sock_rcvtimeo(sk, nonblock);
1294 /* Urgent data needs to be handled specially. */
1295 if (flags & MSG_OOB)
1298 seq = &tp->copied_seq;
1299 if (flags & MSG_PEEK) {
1300 peek_seq = tp->copied_seq;
1304 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1306 #ifdef CONFIG_NET_DMA
1307 tp->ucopy.dma_chan = NULL;
1309 skb = skb_peek_tail(&sk->sk_receive_queue);
1314 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1315 if ((available < target) &&
1316 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1317 !sysctl_tcp_low_latency &&
1318 __get_cpu_var(softnet_data).net_dma) {
1319 preempt_enable_no_resched();
1320 tp->ucopy.pinned_list =
1321 dma_pin_iovec_pages(msg->msg_iov, len);
1323 preempt_enable_no_resched();
1331 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1332 if (tp->urg_data && tp->urg_seq == *seq) {
1335 if (signal_pending(current)) {
1336 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1341 /* Next get a buffer. */
1343 skb = skb_peek(&sk->sk_receive_queue);
1348 /* Now that we have two receive queues this
1351 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1352 printk(KERN_INFO "recvmsg bug: copied %X "
1353 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1356 offset = *seq - TCP_SKB_CB(skb)->seq;
1357 if (tcp_hdr(skb)->syn)
1359 if (offset < skb->len)
1361 if (tcp_hdr(skb)->fin)
1363 WARN_ON(!(flags & MSG_PEEK));
1365 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1367 /* Well, if we have backlog, try to process it now yet. */
1369 if (copied >= target && !sk->sk_backlog.tail)
1374 sk->sk_state == TCP_CLOSE ||
1375 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1377 signal_pending(current))
1380 if (sock_flag(sk, SOCK_DONE))
1384 copied = sock_error(sk);
1388 if (sk->sk_shutdown & RCV_SHUTDOWN)
1391 if (sk->sk_state == TCP_CLOSE) {
1392 if (!sock_flag(sk, SOCK_DONE)) {
1393 /* This occurs when user tries to read
1394 * from never connected socket.
1407 if (signal_pending(current)) {
1408 copied = sock_intr_errno(timeo);
1413 tcp_cleanup_rbuf(sk, copied);
1415 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1416 /* Install new reader */
1417 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1418 user_recv = current;
1419 tp->ucopy.task = user_recv;
1420 tp->ucopy.iov = msg->msg_iov;
1423 tp->ucopy.len = len;
1425 WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1426 !(flags & (MSG_PEEK | MSG_TRUNC)));
1428 /* Ugly... If prequeue is not empty, we have to
1429 * process it before releasing socket, otherwise
1430 * order will be broken at second iteration.
1431 * More elegant solution is required!!!
1433 * Look: we have the following (pseudo)queues:
1435 * 1. packets in flight
1440 * Each queue can be processed only if the next ones
1441 * are empty. At this point we have empty receive_queue.
1442 * But prequeue _can_ be not empty after 2nd iteration,
1443 * when we jumped to start of loop because backlog
1444 * processing added something to receive_queue.
1445 * We cannot release_sock(), because backlog contains
1446 * packets arrived _after_ prequeued ones.
1448 * Shortly, algorithm is clear --- to process all
1449 * the queues in order. We could make it more directly,
1450 * requeueing packets from backlog to prequeue, if
1451 * is not empty. It is more elegant, but eats cycles,
1454 if (!skb_queue_empty(&tp->ucopy.prequeue))
1457 /* __ Set realtime policy in scheduler __ */
1460 if (copied >= target) {
1461 /* Do not sleep, just process backlog. */
1465 sk_wait_data(sk, &timeo);
1467 #ifdef CONFIG_NET_DMA
1468 tp->ucopy.wakeup = 0;
1474 /* __ Restore normal policy in scheduler __ */
1476 if ((chunk = len - tp->ucopy.len) != 0) {
1477 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1482 if (tp->rcv_nxt == tp->copied_seq &&
1483 !skb_queue_empty(&tp->ucopy.prequeue)) {
1485 tcp_prequeue_process(sk);
1487 if ((chunk = len - tp->ucopy.len) != 0) {
1488 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1494 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1495 if (net_ratelimit())
1496 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1497 current->comm, task_pid_nr(current));
1498 peek_seq = tp->copied_seq;
1503 /* Ok so how much can we use? */
1504 used = skb->len - offset;
1508 /* Do we have urgent data here? */
1510 u32 urg_offset = tp->urg_seq - *seq;
1511 if (urg_offset < used) {
1513 if (!sock_flag(sk, SOCK_URGINLINE)) {
1525 if (!(flags & MSG_TRUNC)) {
1526 #ifdef CONFIG_NET_DMA
1527 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1528 tp->ucopy.dma_chan = get_softnet_dma();
1530 if (tp->ucopy.dma_chan) {
1531 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1532 tp->ucopy.dma_chan, skb, offset,
1534 tp->ucopy.pinned_list);
1536 if (tp->ucopy.dma_cookie < 0) {
1538 printk(KERN_ALERT "dma_cookie < 0\n");
1540 /* Exception. Bailout! */
1545 if ((offset + used) == skb->len)
1551 err = skb_copy_datagram_iovec(skb, offset,
1552 msg->msg_iov, used);
1554 /* Exception. Bailout! */
1566 tcp_rcv_space_adjust(sk);
1569 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1571 tcp_fast_path_check(sk);
1573 if (used + offset < skb->len)
1576 if (tcp_hdr(skb)->fin)
1578 if (!(flags & MSG_PEEK)) {
1579 sk_eat_skb(sk, skb, copied_early);
1585 /* Process the FIN. */
1587 if (!(flags & MSG_PEEK)) {
1588 sk_eat_skb(sk, skb, copied_early);
1595 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1598 tp->ucopy.len = copied > 0 ? len : 0;
1600 tcp_prequeue_process(sk);
1602 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1603 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1609 tp->ucopy.task = NULL;
1613 #ifdef CONFIG_NET_DMA
1614 if (tp->ucopy.dma_chan) {
1615 dma_cookie_t done, used;
1617 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1619 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1620 tp->ucopy.dma_cookie, &done,
1621 &used) == DMA_IN_PROGRESS) {
1622 /* do partial cleanup of sk_async_wait_queue */
1623 while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1624 (dma_async_is_complete(skb->dma_cookie, done,
1625 used) == DMA_SUCCESS)) {
1626 __skb_dequeue(&sk->sk_async_wait_queue);
1631 /* Safe to free early-copied skbs now */
1632 __skb_queue_purge(&sk->sk_async_wait_queue);
1633 dma_chan_put(tp->ucopy.dma_chan);
1634 tp->ucopy.dma_chan = NULL;
1636 if (tp->ucopy.pinned_list) {
1637 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1638 tp->ucopy.pinned_list = NULL;
1642 /* According to UNIX98, msg_name/msg_namelen are ignored
1643 * on connected socket. I was just happy when found this 8) --ANK
1646 /* Clean up data we have read: This will do ACK frames. */
1647 tcp_cleanup_rbuf(sk, copied);
1649 TCP_CHECK_TIMER(sk);
1654 TCP_CHECK_TIMER(sk);
1659 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1663 void tcp_set_state(struct sock *sk, int state)
1665 int oldstate = sk->sk_state;
1668 case TCP_ESTABLISHED:
1669 if (oldstate != TCP_ESTABLISHED)
1670 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1674 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1675 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1677 sk->sk_prot->unhash(sk);
1678 if (inet_csk(sk)->icsk_bind_hash &&
1679 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1683 if (oldstate==TCP_ESTABLISHED)
1684 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1687 /* Change state AFTER socket is unhashed to avoid closed
1688 * socket sitting in hash tables.
1690 sk->sk_state = state;
1693 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]);
1696 EXPORT_SYMBOL_GPL(tcp_set_state);
1699 * State processing on a close. This implements the state shift for
1700 * sending our FIN frame. Note that we only send a FIN for some
1701 * states. A shutdown() may have already sent the FIN, or we may be
1705 static const unsigned char new_state[16] = {
1706 /* current state: new state: action: */
1707 /* (Invalid) */ TCP_CLOSE,
1708 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1709 /* TCP_SYN_SENT */ TCP_CLOSE,
1710 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1711 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1712 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1713 /* TCP_TIME_WAIT */ TCP_CLOSE,
1714 /* TCP_CLOSE */ TCP_CLOSE,
1715 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1716 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1717 /* TCP_LISTEN */ TCP_CLOSE,
1718 /* TCP_CLOSING */ TCP_CLOSING,
1721 static int tcp_close_state(struct sock *sk)
1723 int next = (int)new_state[sk->sk_state];
1724 int ns = next & TCP_STATE_MASK;
1726 tcp_set_state(sk, ns);
1728 return next & TCP_ACTION_FIN;
1732 * Shutdown the sending side of a connection. Much like close except
1733 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1736 void tcp_shutdown(struct sock *sk, int how)
1738 /* We need to grab some memory, and put together a FIN,
1739 * and then put it into the queue to be sent.
1740 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1742 if (!(how & SEND_SHUTDOWN))
1745 /* If we've already sent a FIN, or it's a closed state, skip this. */
1746 if ((1 << sk->sk_state) &
1747 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1748 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1749 /* Clear out any half completed packets. FIN if needed. */
1750 if (tcp_close_state(sk))
1755 void tcp_close(struct sock *sk, long timeout)
1757 struct sk_buff *skb;
1758 int data_was_unread = 0;
1762 sk->sk_shutdown = SHUTDOWN_MASK;
1764 if (sk->sk_state == TCP_LISTEN) {
1765 tcp_set_state(sk, TCP_CLOSE);
1768 inet_csk_listen_stop(sk);
1770 goto adjudge_to_death;
1773 /* We need to flush the recv. buffs. We do this only on the
1774 * descriptor close, not protocol-sourced closes, because the
1775 * reader process may not have drained the data yet!
1777 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1778 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1780 data_was_unread += len;
1786 /* As outlined in RFC 2525, section 2.17, we send a RST here because
1787 * data was lost. To witness the awful effects of the old behavior of
1788 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1789 * GET in an FTP client, suspend the process, wait for the client to
1790 * advertise a zero window, then kill -9 the FTP client, wheee...
1791 * Note: timeout is always zero in such a case.
1793 if (data_was_unread) {
1794 /* Unread data was tossed, zap the connection. */
1795 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1796 tcp_set_state(sk, TCP_CLOSE);
1797 tcp_send_active_reset(sk, GFP_KERNEL);
1798 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1799 /* Check zero linger _after_ checking for unread data. */
1800 sk->sk_prot->disconnect(sk, 0);
1801 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1802 } else if (tcp_close_state(sk)) {
1803 /* We FIN if the application ate all the data before
1804 * zapping the connection.
1807 /* RED-PEN. Formally speaking, we have broken TCP state
1808 * machine. State transitions:
1810 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1811 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1812 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1814 * are legal only when FIN has been sent (i.e. in window),
1815 * rather than queued out of window. Purists blame.
1817 * F.e. "RFC state" is ESTABLISHED,
1818 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1820 * The visible declinations are that sometimes
1821 * we enter time-wait state, when it is not required really
1822 * (harmless), do not send active resets, when they are
1823 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1824 * they look as CLOSING or LAST_ACK for Linux)
1825 * Probably, I missed some more holelets.
1831 sk_stream_wait_close(sk, timeout);
1834 state = sk->sk_state;
1837 atomic_inc(sk->sk_prot->orphan_count);
1839 /* It is the last release_sock in its life. It will remove backlog. */
1843 /* Now socket is owned by kernel and we acquire BH lock
1844 to finish close. No need to check for user refs.
1848 WARN_ON(sock_owned_by_user(sk));
1850 /* Have we already been destroyed by a softirq or backlog? */
1851 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1854 /* This is a (useful) BSD violating of the RFC. There is a
1855 * problem with TCP as specified in that the other end could
1856 * keep a socket open forever with no application left this end.
1857 * We use a 3 minute timeout (about the same as BSD) then kill
1858 * our end. If they send after that then tough - BUT: long enough
1859 * that we won't make the old 4*rto = almost no time - whoops
1862 * Nope, it was not mistake. It is really desired behaviour
1863 * f.e. on http servers, when such sockets are useless, but
1864 * consume significant resources. Let's do it with special
1865 * linger2 option. --ANK
1868 if (sk->sk_state == TCP_FIN_WAIT2) {
1869 struct tcp_sock *tp = tcp_sk(sk);
1870 if (tp->linger2 < 0) {
1871 tcp_set_state(sk, TCP_CLOSE);
1872 tcp_send_active_reset(sk, GFP_ATOMIC);
1873 NET_INC_STATS_BH(sock_net(sk),
1874 LINUX_MIB_TCPABORTONLINGER);
1876 const int tmo = tcp_fin_time(sk);
1878 if (tmo > TCP_TIMEWAIT_LEN) {
1879 inet_csk_reset_keepalive_timer(sk,
1880 tmo - TCP_TIMEWAIT_LEN);
1882 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1887 if (sk->sk_state != TCP_CLOSE) {
1889 if (tcp_too_many_orphans(sk,
1890 atomic_read(sk->sk_prot->orphan_count))) {
1891 if (net_ratelimit())
1892 printk(KERN_INFO "TCP: too many of orphaned "
1894 tcp_set_state(sk, TCP_CLOSE);
1895 tcp_send_active_reset(sk, GFP_ATOMIC);
1896 NET_INC_STATS_BH(sock_net(sk),
1897 LINUX_MIB_TCPABORTONMEMORY);
1901 if (sk->sk_state == TCP_CLOSE)
1902 inet_csk_destroy_sock(sk);
1903 /* Otherwise, socket is reprieved until protocol close. */
1911 /* These states need RST on ABORT according to RFC793 */
1913 static inline int tcp_need_reset(int state)
1915 return (1 << state) &
1916 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1917 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1920 int tcp_disconnect(struct sock *sk, int flags)
1922 struct inet_sock *inet = inet_sk(sk);
1923 struct inet_connection_sock *icsk = inet_csk(sk);
1924 struct tcp_sock *tp = tcp_sk(sk);
1926 int old_state = sk->sk_state;
1928 if (old_state != TCP_CLOSE)
1929 tcp_set_state(sk, TCP_CLOSE);
1931 /* ABORT function of RFC793 */
1932 if (old_state == TCP_LISTEN) {
1933 inet_csk_listen_stop(sk);
1934 } else if (tcp_need_reset(old_state) ||
1935 (tp->snd_nxt != tp->write_seq &&
1936 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1937 /* The last check adjusts for discrepancy of Linux wrt. RFC
1940 tcp_send_active_reset(sk, gfp_any());
1941 sk->sk_err = ECONNRESET;
1942 } else if (old_state == TCP_SYN_SENT)
1943 sk->sk_err = ECONNRESET;
1945 tcp_clear_xmit_timers(sk);
1946 __skb_queue_purge(&sk->sk_receive_queue);
1947 tcp_write_queue_purge(sk);
1948 __skb_queue_purge(&tp->out_of_order_queue);
1949 #ifdef CONFIG_NET_DMA
1950 __skb_queue_purge(&sk->sk_async_wait_queue);
1955 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1956 inet_reset_saddr(sk);
1958 sk->sk_shutdown = 0;
1959 sock_reset_flag(sk, SOCK_DONE);
1961 if ((tp->write_seq += tp->max_window + 2) == 0)
1963 icsk->icsk_backoff = 0;
1965 icsk->icsk_probes_out = 0;
1966 tp->packets_out = 0;
1967 tp->snd_ssthresh = 0x7fffffff;
1968 tp->snd_cwnd_cnt = 0;
1969 tp->bytes_acked = 0;
1970 tcp_set_ca_state(sk, TCP_CA_Open);
1971 tcp_clear_retrans(tp);
1972 inet_csk_delack_init(sk);
1973 tcp_init_send_head(sk);
1974 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
1977 WARN_ON(inet->num && !icsk->icsk_bind_hash);
1979 sk->sk_error_report(sk);
1984 * Socket option code for TCP.
1986 static int do_tcp_setsockopt(struct sock *sk, int level,
1987 int optname, char __user *optval, int optlen)
1989 struct tcp_sock *tp = tcp_sk(sk);
1990 struct inet_connection_sock *icsk = inet_csk(sk);
1994 /* This is a string value all the others are int's */
1995 if (optname == TCP_CONGESTION) {
1996 char name[TCP_CA_NAME_MAX];
2001 val = strncpy_from_user(name, optval,
2002 min(TCP_CA_NAME_MAX-1, optlen));
2008 err = tcp_set_congestion_control(sk, name);
2013 if (optlen < sizeof(int))
2016 if (get_user(val, (int __user *)optval))
2023 /* Values greater than interface MTU won't take effect. However
2024 * at the point when this call is done we typically don't yet
2025 * know which interface is going to be used */
2026 if (val < 8 || val > MAX_TCP_WINDOW) {
2030 tp->rx_opt.user_mss = val;
2035 /* TCP_NODELAY is weaker than TCP_CORK, so that
2036 * this option on corked socket is remembered, but
2037 * it is not activated until cork is cleared.
2039 * However, when TCP_NODELAY is set we make
2040 * an explicit push, which overrides even TCP_CORK
2041 * for currently queued segments.
2043 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2044 tcp_push_pending_frames(sk);
2046 tp->nonagle &= ~TCP_NAGLE_OFF;
2051 /* When set indicates to always queue non-full frames.
2052 * Later the user clears this option and we transmit
2053 * any pending partial frames in the queue. This is
2054 * meant to be used alongside sendfile() to get properly
2055 * filled frames when the user (for example) must write
2056 * out headers with a write() call first and then use
2057 * sendfile to send out the data parts.
2059 * TCP_CORK can be set together with TCP_NODELAY and it is
2060 * stronger than TCP_NODELAY.
2063 tp->nonagle |= TCP_NAGLE_CORK;
2065 tp->nonagle &= ~TCP_NAGLE_CORK;
2066 if (tp->nonagle&TCP_NAGLE_OFF)
2067 tp->nonagle |= TCP_NAGLE_PUSH;
2068 tcp_push_pending_frames(sk);
2073 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2076 tp->keepalive_time = val * HZ;
2077 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2078 !((1 << sk->sk_state) &
2079 (TCPF_CLOSE | TCPF_LISTEN))) {
2080 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2081 if (tp->keepalive_time > elapsed)
2082 elapsed = tp->keepalive_time - elapsed;
2085 inet_csk_reset_keepalive_timer(sk, elapsed);
2090 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2093 tp->keepalive_intvl = val * HZ;
2096 if (val < 1 || val > MAX_TCP_KEEPCNT)
2099 tp->keepalive_probes = val;
2102 if (val < 1 || val > MAX_TCP_SYNCNT)
2105 icsk->icsk_syn_retries = val;
2111 else if (val > sysctl_tcp_fin_timeout / HZ)
2114 tp->linger2 = val * HZ;
2117 case TCP_DEFER_ACCEPT:
2118 icsk->icsk_accept_queue.rskq_defer_accept = 0;
2120 /* Translate value in seconds to number of
2122 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
2123 val > ((TCP_TIMEOUT_INIT / HZ) <<
2124 icsk->icsk_accept_queue.rskq_defer_accept))
2125 icsk->icsk_accept_queue.rskq_defer_accept++;
2126 icsk->icsk_accept_queue.rskq_defer_accept++;
2130 case TCP_WINDOW_CLAMP:
2132 if (sk->sk_state != TCP_CLOSE) {
2136 tp->window_clamp = 0;
2138 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2139 SOCK_MIN_RCVBUF / 2 : val;
2144 icsk->icsk_ack.pingpong = 1;
2146 icsk->icsk_ack.pingpong = 0;
2147 if ((1 << sk->sk_state) &
2148 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2149 inet_csk_ack_scheduled(sk)) {
2150 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2151 tcp_cleanup_rbuf(sk, 1);
2153 icsk->icsk_ack.pingpong = 1;
2158 #ifdef CONFIG_TCP_MD5SIG
2160 /* Read the IP->Key mappings from userspace */
2161 err = tp->af_specific->md5_parse(sk, optval, optlen);
2174 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2177 struct inet_connection_sock *icsk = inet_csk(sk);
2179 if (level != SOL_TCP)
2180 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2182 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2185 #ifdef CONFIG_COMPAT
2186 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2187 char __user *optval, int optlen)
2189 if (level != SOL_TCP)
2190 return inet_csk_compat_setsockopt(sk, level, optname,
2192 return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2195 EXPORT_SYMBOL(compat_tcp_setsockopt);
2198 /* Return information about state of tcp endpoint in API format. */
2199 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2201 struct tcp_sock *tp = tcp_sk(sk);
2202 const struct inet_connection_sock *icsk = inet_csk(sk);
2203 u32 now = tcp_time_stamp;
2205 memset(info, 0, sizeof(*info));
2207 info->tcpi_state = sk->sk_state;
2208 info->tcpi_ca_state = icsk->icsk_ca_state;
2209 info->tcpi_retransmits = icsk->icsk_retransmits;
2210 info->tcpi_probes = icsk->icsk_probes_out;
2211 info->tcpi_backoff = icsk->icsk_backoff;
2213 if (tp->rx_opt.tstamp_ok)
2214 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2215 if (tcp_is_sack(tp))
2216 info->tcpi_options |= TCPI_OPT_SACK;
2217 if (tp->rx_opt.wscale_ok) {
2218 info->tcpi_options |= TCPI_OPT_WSCALE;
2219 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2220 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2223 if (tp->ecn_flags&TCP_ECN_OK)
2224 info->tcpi_options |= TCPI_OPT_ECN;
2226 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2227 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2228 info->tcpi_snd_mss = tp->mss_cache;
2229 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2231 if (sk->sk_state == TCP_LISTEN) {
2232 info->tcpi_unacked = sk->sk_ack_backlog;
2233 info->tcpi_sacked = sk->sk_max_ack_backlog;
2235 info->tcpi_unacked = tp->packets_out;
2236 info->tcpi_sacked = tp->sacked_out;
2238 info->tcpi_lost = tp->lost_out;
2239 info->tcpi_retrans = tp->retrans_out;
2240 info->tcpi_fackets = tp->fackets_out;
2242 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2243 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2244 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2246 info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2247 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2248 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2249 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2250 info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2251 info->tcpi_snd_cwnd = tp->snd_cwnd;
2252 info->tcpi_advmss = tp->advmss;
2253 info->tcpi_reordering = tp->reordering;
2255 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2256 info->tcpi_rcv_space = tp->rcvq_space.space;
2258 info->tcpi_total_retrans = tp->total_retrans;
2261 EXPORT_SYMBOL_GPL(tcp_get_info);
2263 static int do_tcp_getsockopt(struct sock *sk, int level,
2264 int optname, char __user *optval, int __user *optlen)
2266 struct inet_connection_sock *icsk = inet_csk(sk);
2267 struct tcp_sock *tp = tcp_sk(sk);
2270 if (get_user(len, optlen))
2273 len = min_t(unsigned int, len, sizeof(int));
2280 val = tp->mss_cache;
2281 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2282 val = tp->rx_opt.user_mss;
2285 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2288 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2291 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2294 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2297 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2300 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2305 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2307 case TCP_DEFER_ACCEPT:
2308 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2309 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2311 case TCP_WINDOW_CLAMP:
2312 val = tp->window_clamp;
2315 struct tcp_info info;
2317 if (get_user(len, optlen))
2320 tcp_get_info(sk, &info);
2322 len = min_t(unsigned int, len, sizeof(info));
2323 if (put_user(len, optlen))
2325 if (copy_to_user(optval, &info, len))
2330 val = !icsk->icsk_ack.pingpong;
2333 case TCP_CONGESTION:
2334 if (get_user(len, optlen))
2336 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2337 if (put_user(len, optlen))
2339 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2343 return -ENOPROTOOPT;
2346 if (put_user(len, optlen))
2348 if (copy_to_user(optval, &val, len))
2353 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2356 struct inet_connection_sock *icsk = inet_csk(sk);
2358 if (level != SOL_TCP)
2359 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2361 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2364 #ifdef CONFIG_COMPAT
2365 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2366 char __user *optval, int __user *optlen)
2368 if (level != SOL_TCP)
2369 return inet_csk_compat_getsockopt(sk, level, optname,
2371 return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2374 EXPORT_SYMBOL(compat_tcp_getsockopt);
2377 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2379 struct sk_buff *segs = ERR_PTR(-EINVAL);
2384 unsigned int oldlen;
2387 if (!pskb_may_pull(skb, sizeof(*th)))
2391 thlen = th->doff * 4;
2392 if (thlen < sizeof(*th))
2395 if (!pskb_may_pull(skb, thlen))
2398 oldlen = (u16)~skb->len;
2399 __skb_pull(skb, thlen);
2401 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2402 /* Packet is from an untrusted source, reset gso_segs. */
2403 int type = skb_shinfo(skb)->gso_type;
2412 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2415 mss = skb_shinfo(skb)->gso_size;
2416 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2422 segs = skb_segment(skb, features);
2426 len = skb_shinfo(skb)->gso_size;
2427 delta = htonl(oldlen + (thlen + len));
2431 seq = ntohl(th->seq);
2434 th->fin = th->psh = 0;
2436 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2437 (__force u32)delta));
2438 if (skb->ip_summed != CHECKSUM_PARTIAL)
2440 csum_fold(csum_partial(skb_transport_header(skb),
2447 th->seq = htonl(seq);
2449 } while (skb->next);
2451 delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2453 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2454 (__force u32)delta));
2455 if (skb->ip_summed != CHECKSUM_PARTIAL)
2456 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2462 EXPORT_SYMBOL(tcp_tso_segment);
2464 #ifdef CONFIG_TCP_MD5SIG
2465 static unsigned long tcp_md5sig_users;
2466 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2467 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2469 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2472 for_each_possible_cpu(cpu) {
2473 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2475 if (p->md5_desc.tfm)
2476 crypto_free_hash(p->md5_desc.tfm);
2484 void tcp_free_md5sig_pool(void)
2486 struct tcp_md5sig_pool **pool = NULL;
2488 spin_lock_bh(&tcp_md5sig_pool_lock);
2489 if (--tcp_md5sig_users == 0) {
2490 pool = tcp_md5sig_pool;
2491 tcp_md5sig_pool = NULL;
2493 spin_unlock_bh(&tcp_md5sig_pool_lock);
2495 __tcp_free_md5sig_pool(pool);
2498 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2500 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
2503 struct tcp_md5sig_pool **pool;
2505 pool = alloc_percpu(struct tcp_md5sig_pool *);
2509 for_each_possible_cpu(cpu) {
2510 struct tcp_md5sig_pool *p;
2511 struct crypto_hash *hash;
2513 p = kzalloc(sizeof(*p), GFP_KERNEL);
2516 *per_cpu_ptr(pool, cpu) = p;
2518 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2519 if (!hash || IS_ERR(hash))
2522 p->md5_desc.tfm = hash;
2526 __tcp_free_md5sig_pool(pool);
2530 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
2532 struct tcp_md5sig_pool **pool;
2536 spin_lock_bh(&tcp_md5sig_pool_lock);
2537 pool = tcp_md5sig_pool;
2538 if (tcp_md5sig_users++ == 0) {
2540 spin_unlock_bh(&tcp_md5sig_pool_lock);
2543 spin_unlock_bh(&tcp_md5sig_pool_lock);
2547 spin_unlock_bh(&tcp_md5sig_pool_lock);
2550 /* we cannot hold spinlock here because this may sleep. */
2551 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
2552 spin_lock_bh(&tcp_md5sig_pool_lock);
2555 spin_unlock_bh(&tcp_md5sig_pool_lock);
2558 pool = tcp_md5sig_pool;
2560 /* oops, it has already been assigned. */
2561 spin_unlock_bh(&tcp_md5sig_pool_lock);
2562 __tcp_free_md5sig_pool(p);
2564 tcp_md5sig_pool = pool = p;
2565 spin_unlock_bh(&tcp_md5sig_pool_lock);
2571 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2573 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2575 struct tcp_md5sig_pool **p;
2576 spin_lock_bh(&tcp_md5sig_pool_lock);
2577 p = tcp_md5sig_pool;
2580 spin_unlock_bh(&tcp_md5sig_pool_lock);
2581 return (p ? *per_cpu_ptr(p, cpu) : NULL);
2584 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2586 void __tcp_put_md5sig_pool(void)
2588 tcp_free_md5sig_pool();
2591 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2593 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2596 struct scatterlist sg;
2599 __sum16 old_checksum = th->check;
2601 /* options aren't included in the hash */
2602 sg_init_one(&sg, th, sizeof(struct tcphdr));
2603 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
2604 th->check = old_checksum;
2608 EXPORT_SYMBOL(tcp_md5_hash_header);
2610 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2611 struct sk_buff *skb, unsigned header_len)
2613 struct scatterlist sg;
2614 const struct tcphdr *tp = tcp_hdr(skb);
2615 struct hash_desc *desc = &hp->md5_desc;
2617 const unsigned head_data_len = skb_headlen(skb) > header_len ?
2618 skb_headlen(skb) - header_len : 0;
2619 const struct skb_shared_info *shi = skb_shinfo(skb);
2621 sg_init_table(&sg, 1);
2623 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
2624 if (crypto_hash_update(desc, &sg, head_data_len))
2627 for (i = 0; i < shi->nr_frags; ++i) {
2628 const struct skb_frag_struct *f = &shi->frags[i];
2629 sg_set_page(&sg, f->page, f->size, f->page_offset);
2630 if (crypto_hash_update(desc, &sg, f->size))
2637 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
2639 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
2641 struct scatterlist sg;
2643 sg_init_one(&sg, key->key, key->keylen);
2644 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
2647 EXPORT_SYMBOL(tcp_md5_hash_key);
2651 void tcp_done(struct sock *sk)
2653 if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2654 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
2656 tcp_set_state(sk, TCP_CLOSE);
2657 tcp_clear_xmit_timers(sk);
2659 sk->sk_shutdown = SHUTDOWN_MASK;
2661 if (!sock_flag(sk, SOCK_DEAD))
2662 sk->sk_state_change(sk);
2664 inet_csk_destroy_sock(sk);
2666 EXPORT_SYMBOL_GPL(tcp_done);
2668 extern struct tcp_congestion_ops tcp_reno;
2670 static __initdata unsigned long thash_entries;
2671 static int __init set_thash_entries(char *str)
2675 thash_entries = simple_strtoul(str, &str, 0);
2678 __setup("thash_entries=", set_thash_entries);
2680 void __init tcp_init(void)
2682 struct sk_buff *skb = NULL;
2683 unsigned long nr_pages, limit;
2684 int order, i, max_share;
2686 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
2688 tcp_hashinfo.bind_bucket_cachep =
2689 kmem_cache_create("tcp_bind_bucket",
2690 sizeof(struct inet_bind_bucket), 0,
2691 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2693 /* Size and allocate the main established and bind bucket
2696 * The methodology is similar to that of the buffer cache.
2698 tcp_hashinfo.ehash =
2699 alloc_large_system_hash("TCP established",
2700 sizeof(struct inet_ehash_bucket),
2702 (num_physpages >= 128 * 1024) ?
2705 &tcp_hashinfo.ehash_size,
2707 thash_entries ? 0 : 512 * 1024);
2708 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2709 for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2710 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2711 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain);
2713 if (inet_ehash_locks_alloc(&tcp_hashinfo))
2714 panic("TCP: failed to alloc ehash_locks");
2715 tcp_hashinfo.bhash =
2716 alloc_large_system_hash("TCP bind",
2717 sizeof(struct inet_bind_hashbucket),
2718 tcp_hashinfo.ehash_size,
2719 (num_physpages >= 128 * 1024) ?
2722 &tcp_hashinfo.bhash_size,
2725 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2726 for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2727 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2728 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2731 /* Try to be a bit smarter and adjust defaults depending
2732 * on available memory.
2734 for (order = 0; ((1 << order) << PAGE_SHIFT) <
2735 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2739 tcp_death_row.sysctl_max_tw_buckets = 180000;
2740 sysctl_tcp_max_orphans = 4096 << (order - 4);
2741 sysctl_max_syn_backlog = 1024;
2742 } else if (order < 3) {
2743 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2744 sysctl_tcp_max_orphans >>= (3 - order);
2745 sysctl_max_syn_backlog = 128;
2748 /* Set the pressure threshold to be a fraction of global memory that
2749 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2750 * memory, with a floor of 128 pages.
2752 nr_pages = totalram_pages - totalhigh_pages;
2753 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
2754 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
2755 limit = max(limit, 128UL);
2756 sysctl_tcp_mem[0] = limit / 4 * 3;
2757 sysctl_tcp_mem[1] = limit;
2758 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
2760 /* Set per-socket limits to no more than 1/128 the pressure threshold */
2761 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2762 max_share = min(4UL*1024*1024, limit);
2764 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
2765 sysctl_tcp_wmem[1] = 16*1024;
2766 sysctl_tcp_wmem[2] = max(64*1024, max_share);
2768 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
2769 sysctl_tcp_rmem[1] = 87380;
2770 sysctl_tcp_rmem[2] = max(87380, max_share);
2772 printk(KERN_INFO "TCP: Hash tables configured "
2773 "(established %d bind %d)\n",
2774 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
2776 tcp_register_congestion_control(&tcp_reno);
2779 EXPORT_SYMBOL(tcp_close);
2780 EXPORT_SYMBOL(tcp_disconnect);
2781 EXPORT_SYMBOL(tcp_getsockopt);
2782 EXPORT_SYMBOL(tcp_ioctl);
2783 EXPORT_SYMBOL(tcp_poll);
2784 EXPORT_SYMBOL(tcp_read_sock);
2785 EXPORT_SYMBOL(tcp_recvmsg);
2786 EXPORT_SYMBOL(tcp_sendmsg);
2787 EXPORT_SYMBOL(tcp_splice_read);
2788 EXPORT_SYMBOL(tcp_sendpage);
2789 EXPORT_SYMBOL(tcp_setsockopt);
2790 EXPORT_SYMBOL(tcp_shutdown);