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 $
10 * Authors: Ross Biro, <bir7@leland.Stanford.Edu>
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/config.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/smp_lock.h>
257 #include <linux/fs.h>
258 #include <linux/random.h>
260 #include <net/icmp.h>
262 #include <net/xfrm.h>
266 #include <asm/uaccess.h>
267 #include <asm/ioctls.h>
269 int sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
271 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics);
273 kmem_cache_t *tcp_openreq_cachep;
274 kmem_cache_t *tcp_bucket_cachep;
275 kmem_cache_t *tcp_timewait_cachep;
277 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
279 int sysctl_tcp_default_win_scale;
281 int sysctl_tcp_mem[3];
282 int sysctl_tcp_wmem[3] = { 4 * 1024, 16 * 1024, 128 * 1024 };
283 int sysctl_tcp_rmem[3] = { 4 * 1024, 87380, 87380 * 2 };
285 atomic_t tcp_memory_allocated; /* Current allocated memory. */
286 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
288 /* Pressure flag: try to collapse.
289 * Technical note: it is used by multiple contexts non atomically.
290 * All the tcp_mem_schedule() is of this nature: accounting
291 * is strict, actions are advisory and have some latency. */
292 int tcp_memory_pressure;
294 #define TCP_PAGES(amt) (((amt) + TCP_MEM_QUANTUM - 1) / TCP_MEM_QUANTUM)
296 int tcp_mem_schedule(struct sock *sk, int size, int kind)
298 int amt = TCP_PAGES(size);
300 sk->sk_forward_alloc += amt * TCP_MEM_QUANTUM;
301 atomic_add(amt, &tcp_memory_allocated);
304 if (atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0]) {
305 if (tcp_memory_pressure)
306 tcp_memory_pressure = 0;
310 /* Over hard limit. */
311 if (atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]) {
312 tcp_enter_memory_pressure();
313 goto suppress_allocation;
316 /* Under pressure. */
317 if (atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[1])
318 tcp_enter_memory_pressure();
321 if (atomic_read(&sk->sk_rmem_alloc) < sysctl_tcp_rmem[0])
323 } else if (sk->sk_wmem_queued < sysctl_tcp_wmem[0])
326 if (!tcp_memory_pressure ||
327 sysctl_tcp_mem[2] > atomic_read(&tcp_sockets_allocated) *
328 TCP_PAGES(sk->sk_wmem_queued +
329 atomic_read(&sk->sk_rmem_alloc) +
330 sk->sk_forward_alloc))
336 tcp_moderate_sndbuf(sk);
338 /* Fail only if socket is _under_ its sndbuf.
339 * In this case we cannot block, so that we have to fail.
341 if (sk->sk_wmem_queued + size >= sk->sk_sndbuf)
345 /* Alas. Undo changes. */
346 sk->sk_forward_alloc -= amt * TCP_MEM_QUANTUM;
347 atomic_sub(amt, &tcp_memory_allocated);
351 void __tcp_mem_reclaim(struct sock *sk)
353 if (sk->sk_forward_alloc >= TCP_MEM_QUANTUM) {
354 atomic_sub(sk->sk_forward_alloc / TCP_MEM_QUANTUM,
355 &tcp_memory_allocated);
356 sk->sk_forward_alloc &= TCP_MEM_QUANTUM - 1;
357 if (tcp_memory_pressure &&
358 atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0])
359 tcp_memory_pressure = 0;
363 void tcp_rfree(struct sk_buff *skb)
365 struct sock *sk = skb->sk;
367 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
368 sk->sk_forward_alloc += skb->truesize;
372 * LISTEN is a special case for poll..
374 static __inline__ unsigned int tcp_listen_poll(struct sock *sk,
377 return tcp_sk(sk)->accept_queue ? (POLLIN | POLLRDNORM) : 0;
381 * Wait for a TCP event.
383 * Note that we don't need to lock the socket, as the upper poll layers
384 * take care of normal races (between the test and the event) and we don't
385 * go look at any of the socket buffers directly.
387 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
390 struct sock *sk = sock->sk;
391 struct tcp_opt *tp = tcp_sk(sk);
393 poll_wait(file, sk->sk_sleep, wait);
394 if (sk->sk_state == TCP_LISTEN)
395 return tcp_listen_poll(sk, wait);
397 /* Socket is not locked. We are protected from async events
398 by poll logic and correct handling of state changes
399 made by another threads is impossible in any case.
407 * POLLHUP is certainly not done right. But poll() doesn't
408 * have a notion of HUP in just one direction, and for a
409 * socket the read side is more interesting.
411 * Some poll() documentation says that POLLHUP is incompatible
412 * with the POLLOUT/POLLWR flags, so somebody should check this
413 * all. But careful, it tends to be safer to return too many
414 * bits than too few, and you can easily break real applications
415 * if you don't tell them that something has hung up!
419 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
420 * our fs/select.c). It means that after we received EOF,
421 * poll always returns immediately, making impossible poll() on write()
422 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
423 * if and only if shutdown has been made in both directions.
424 * Actually, it is interesting to look how Solaris and DUX
425 * solve this dilemma. I would prefer, if PULLHUP were maskable,
426 * then we could set it on SND_SHUTDOWN. BTW examples given
427 * in Stevens' books assume exactly this behaviour, it explains
428 * why PULLHUP is incompatible with POLLOUT. --ANK
430 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
431 * blocking on fresh not-connected or disconnected socket. --ANK
433 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
435 if (sk->sk_shutdown & RCV_SHUTDOWN)
436 mask |= POLLIN | POLLRDNORM;
439 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
440 /* Potential race condition. If read of tp below will
441 * escape above sk->sk_state, we can be illegally awaken
442 * in SYN_* states. */
443 if ((tp->rcv_nxt != tp->copied_seq) &&
444 (tp->urg_seq != tp->copied_seq ||
445 tp->rcv_nxt != tp->copied_seq + 1 ||
446 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
447 mask |= POLLIN | POLLRDNORM;
449 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
450 if (tcp_wspace(sk) >= tcp_min_write_space(sk)) {
451 mask |= POLLOUT | POLLWRNORM;
452 } else { /* send SIGIO later */
453 set_bit(SOCK_ASYNC_NOSPACE,
454 &sk->sk_socket->flags);
455 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
457 /* Race breaker. If space is freed after
458 * wspace test but before the flags are set,
459 * IO signal will be lost.
461 if (tcp_wspace(sk) >= tcp_min_write_space(sk))
462 mask |= POLLOUT | POLLWRNORM;
466 if (tp->urg_data & TCP_URG_VALID)
473 * TCP socket write_space callback.
475 void tcp_write_space(struct sock *sk)
477 struct socket *sock = sk->sk_socket;
479 if (tcp_wspace(sk) >= tcp_min_write_space(sk) && sock) {
480 clear_bit(SOCK_NOSPACE, &sock->flags);
482 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
483 wake_up_interruptible(sk->sk_sleep);
485 if (sock->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
486 sock_wake_async(sock, 2, POLL_OUT);
490 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
492 struct tcp_opt *tp = tcp_sk(sk);
497 if (sk->sk_state == TCP_LISTEN)
501 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
503 else if (sock_flag(sk, SOCK_URGINLINE) ||
505 before(tp->urg_seq, tp->copied_seq) ||
506 !before(tp->urg_seq, tp->rcv_nxt)) {
507 answ = tp->rcv_nxt - tp->copied_seq;
509 /* Subtract 1, if FIN is in queue. */
510 if (answ && !skb_queue_empty(&sk->sk_receive_queue))
512 ((struct sk_buff *)sk->sk_receive_queue.prev)->h.th->fin;
514 answ = tp->urg_seq - tp->copied_seq;
518 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
521 if (sk->sk_state == TCP_LISTEN)
524 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
527 answ = tp->write_seq - tp->snd_una;
533 return put_user(answ, (int __user *)arg);
537 int tcp_listen_start(struct sock *sk)
539 struct inet_opt *inet = inet_sk(sk);
540 struct tcp_opt *tp = tcp_sk(sk);
541 struct tcp_listen_opt *lopt;
543 sk->sk_max_ack_backlog = 0;
544 sk->sk_ack_backlog = 0;
545 tp->accept_queue = tp->accept_queue_tail = NULL;
546 tp->syn_wait_lock = RW_LOCK_UNLOCKED;
549 lopt = kmalloc(sizeof(struct tcp_listen_opt), GFP_KERNEL);
553 memset(lopt, 0, sizeof(struct tcp_listen_opt));
554 for (lopt->max_qlen_log = 6; ; lopt->max_qlen_log++)
555 if ((1 << lopt->max_qlen_log) >= sysctl_max_syn_backlog)
557 get_random_bytes(&lopt->hash_rnd, 4);
559 write_lock_bh(&tp->syn_wait_lock);
560 tp->listen_opt = lopt;
561 write_unlock_bh(&tp->syn_wait_lock);
563 /* There is race window here: we announce ourselves listening,
564 * but this transition is still not validated by get_port().
565 * It is OK, because this socket enters to hash table only
566 * after validation is complete.
568 sk->sk_state = TCP_LISTEN;
569 if (!sk->sk_prot->get_port(sk, inet->num)) {
570 inet->sport = htons(inet->num);
573 sk->sk_prot->hash(sk);
578 sk->sk_state = TCP_CLOSE;
579 write_lock_bh(&tp->syn_wait_lock);
580 tp->listen_opt = NULL;
581 write_unlock_bh(&tp->syn_wait_lock);
587 * This routine closes sockets which have been at least partially
588 * opened, but not yet accepted.
591 static void tcp_listen_stop (struct sock *sk)
593 struct tcp_opt *tp = tcp_sk(sk);
594 struct tcp_listen_opt *lopt = tp->listen_opt;
595 struct open_request *acc_req = tp->accept_queue;
596 struct open_request *req;
599 tcp_delete_keepalive_timer(sk);
601 /* make all the listen_opt local to us */
602 write_lock_bh(&tp->syn_wait_lock);
603 tp->listen_opt = NULL;
604 write_unlock_bh(&tp->syn_wait_lock);
605 tp->accept_queue = tp->accept_queue_tail = NULL;
608 for (i = 0; i < TCP_SYNQ_HSIZE; i++) {
609 while ((req = lopt->syn_table[i]) != NULL) {
610 lopt->syn_table[i] = req->dl_next;
612 tcp_openreq_free(req);
614 /* Following specs, it would be better either to send FIN
615 * (and enter FIN-WAIT-1, it is normal close)
616 * or to send active reset (abort).
617 * Certainly, it is pretty dangerous while synflood, but it is
618 * bad justification for our negligence 8)
619 * To be honest, we are not able to make either
620 * of the variants now. --ANK
625 BUG_TRAP(!lopt->qlen);
629 while ((req = acc_req) != NULL) {
630 struct sock *child = req->sk;
632 acc_req = req->dl_next;
636 BUG_TRAP(!sock_owned_by_user(child));
639 tcp_disconnect(child, O_NONBLOCK);
643 atomic_inc(&tcp_orphan_count);
645 tcp_destroy_sock(child);
647 bh_unlock_sock(child);
651 sk_acceptq_removed(sk);
652 tcp_openreq_fastfree(req);
654 BUG_TRAP(!sk->sk_ack_backlog);
658 * Wait for a socket to get into the connected state
660 * Note: Must be called with the socket locked.
662 static int wait_for_tcp_connect(struct sock *sk, int flags, long *timeo_p)
664 struct tcp_opt *tp = tcp_sk(sk);
665 struct task_struct *tsk = current;
668 while ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
670 return sock_error(sk);
671 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV))
675 if (signal_pending(tsk))
676 return sock_intr_errno(*timeo_p);
678 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
682 *timeo_p = schedule_timeout(*timeo_p);
685 finish_wait(sk->sk_sleep, &wait);
691 static inline int tcp_memory_free(struct sock *sk)
693 return sk->sk_wmem_queued < sk->sk_sndbuf;
697 * Wait for more memory for a socket
699 static int wait_for_tcp_memory(struct sock *sk, long *timeo)
701 struct tcp_opt *tp = tcp_sk(sk);
704 long current_timeo = *timeo;
707 if (tcp_memory_free(sk))
708 current_timeo = vm_wait = (net_random() % (HZ / 5)) + 2;
711 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
713 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
715 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
719 if (signal_pending(current))
721 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
722 if (tcp_memory_free(sk) && !vm_wait)
725 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
728 if (!tcp_memory_free(sk) || vm_wait)
729 current_timeo = schedule_timeout(current_timeo);
734 vm_wait -= current_timeo;
735 current_timeo = *timeo;
736 if (current_timeo != MAX_SCHEDULE_TIMEOUT &&
737 (current_timeo -= vm_wait) < 0)
741 *timeo = current_timeo;
744 finish_wait(sk->sk_sleep, &wait);
754 err = sock_intr_errno(*timeo);
758 static inline int can_coalesce(struct sk_buff *skb, int i, struct page *page,
762 skb_frag_t *frag = &skb_shinfo(skb)->frags[i - 1];
763 return page == frag->page &&
764 off == frag->page_offset + frag->size;
769 static inline void fill_page_desc(struct sk_buff *skb, int i,
770 struct page *page, int off, int size)
772 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
774 frag->page_offset = off;
776 skb_shinfo(skb)->nr_frags = i + 1;
779 static inline void tcp_mark_push(struct tcp_opt *tp, struct sk_buff *skb)
781 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
782 tp->pushed_seq = tp->write_seq;
785 static inline int forced_push(struct tcp_opt *tp)
787 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
790 static inline void skb_entail(struct sock *sk, struct tcp_opt *tp,
794 TCP_SKB_CB(skb)->seq = tp->write_seq;
795 TCP_SKB_CB(skb)->end_seq = tp->write_seq;
796 TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
797 TCP_SKB_CB(skb)->sacked = 0;
798 __skb_queue_tail(&sk->sk_write_queue, skb);
799 tcp_charge_skb(sk, skb);
802 else if (tp->nonagle&TCP_NAGLE_PUSH)
803 tp->nonagle &= ~TCP_NAGLE_PUSH;
806 static inline void tcp_mark_urg(struct tcp_opt *tp, int flags,
809 if (flags & MSG_OOB) {
811 tp->snd_up = tp->write_seq;
812 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
816 static inline void tcp_push(struct sock *sk, struct tcp_opt *tp, int flags,
817 int mss_now, int nonagle)
820 struct sk_buff *skb = sk->sk_write_queue.prev;
821 if (!(flags & MSG_MORE) || forced_push(tp))
822 tcp_mark_push(tp, skb);
823 tcp_mark_urg(tp, flags, skb);
824 __tcp_push_pending_frames(sk, tp, mss_now,
825 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
829 static int tcp_error(struct sock *sk, int flags, int err)
832 err = sock_error(sk) ? : -EPIPE;
833 if (err == -EPIPE && !(flags & MSG_NOSIGNAL))
834 send_sig(SIGPIPE, current, 0);
838 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
839 size_t psize, int flags)
841 struct tcp_opt *tp = tcp_sk(sk);
845 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
847 /* Wait for a connection to finish. */
848 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
849 if ((err = wait_for_tcp_connect(sk, 0, &timeo)) != 0)
852 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
854 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
858 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
862 struct sk_buff *skb = sk->sk_write_queue.prev;
863 struct page *page = pages[poffset / PAGE_SIZE];
865 int offset = poffset % PAGE_SIZE;
866 int size = min_t(size_t, psize, PAGE_SIZE - offset);
868 if (!tp->send_head || (copy = mss_now - skb->len) <= 0) {
870 if (!tcp_memory_free(sk))
871 goto wait_for_sndbuf;
873 skb = tcp_alloc_pskb(sk, 0, tp->mss_cache,
876 goto wait_for_memory;
878 skb_entail(sk, tp, skb);
885 i = skb_shinfo(skb)->nr_frags;
886 if (can_coalesce(skb, i, page, offset)) {
887 skb_shinfo(skb)->frags[i - 1].size += copy;
888 } else if (i < MAX_SKB_FRAGS) {
890 fill_page_desc(skb, i, page, offset, copy);
892 tcp_mark_push(tp, skb);
897 skb->data_len += copy;
898 skb->ip_summed = CHECKSUM_HW;
899 tp->write_seq += copy;
900 TCP_SKB_CB(skb)->end_seq += copy;
903 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
907 if (!(psize -= copy))
910 if (skb->len != mss_now || (flags & MSG_OOB))
913 if (forced_push(tp)) {
914 tcp_mark_push(tp, skb);
915 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
916 } else if (skb == tp->send_head)
917 tcp_push_one(sk, mss_now);
921 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
924 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
926 if ((err = wait_for_tcp_memory(sk, &timeo)) != 0)
929 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
934 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
941 return tcp_error(sk, flags, err);
944 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
945 size_t size, int flags)
948 struct sock *sk = sock->sk;
950 #define TCP_ZC_CSUM_FLAGS (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)
952 if (!(sk->sk_route_caps & NETIF_F_SG) ||
953 !(sk->sk_route_caps & TCP_ZC_CSUM_FLAGS))
954 return sock_no_sendpage(sock, page, offset, size, flags);
956 #undef TCP_ZC_CSUM_FLAGS
960 res = do_tcp_sendpages(sk, &page, offset, size, flags);
966 #define TCP_PAGE(sk) (inet_sk(sk)->sndmsg_page)
967 #define TCP_OFF(sk) (inet_sk(sk)->sndmsg_off)
969 static inline int tcp_copy_to_page(struct sock *sk, char __user *from,
970 struct sk_buff *skb, struct page *page,
976 if (skb->ip_summed == CHECKSUM_NONE) {
977 csum = csum_and_copy_from_user(from, page_address(page) + off,
980 skb->csum = csum_block_add(skb->csum, csum, skb->len);
982 if (copy_from_user(page_address(page) + off, from, copy))
987 skb->data_len += copy;
988 skb->truesize += copy;
989 sk->sk_wmem_queued += copy;
990 sk->sk_forward_alloc -= copy;
994 static inline int skb_add_data(struct sk_buff *skb, char __user *from, int copy)
1000 if (skb->ip_summed == CHECKSUM_NONE) {
1001 csum = csum_and_copy_from_user(from, skb_put(skb, copy),
1004 skb->csum = csum_block_add(skb->csum, csum, off);
1008 if (!copy_from_user(skb_put(skb, copy), from, copy))
1012 __skb_trim(skb, off);
1016 static inline int select_size(struct sock *sk, struct tcp_opt *tp)
1018 int tmp = tp->mss_cache_std;
1020 if (sk->sk_route_caps & NETIF_F_SG) {
1021 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
1023 if (tmp >= pgbreak &&
1024 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
1030 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1034 struct tcp_opt *tp = tcp_sk(sk);
1035 struct sk_buff *skb;
1042 TCP_CHECK_TIMER(sk);
1044 flags = msg->msg_flags;
1045 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1047 /* Wait for a connection to finish. */
1048 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
1049 if ((err = wait_for_tcp_connect(sk, flags, &timeo)) != 0)
1052 /* This should be in poll */
1053 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1055 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
1057 /* Ok commence sending. */
1058 iovlen = msg->msg_iovlen;
1063 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1066 while (--iovlen >= 0) {
1067 int seglen = iov->iov_len;
1068 unsigned char __user *from = iov->iov_base;
1072 while (seglen > 0) {
1075 skb = sk->sk_write_queue.prev;
1077 if (!tp->send_head ||
1078 (copy = mss_now - skb->len) <= 0) {
1081 /* Allocate new segment. If the interface is SG,
1082 * allocate skb fitting to single page.
1084 if (!tcp_memory_free(sk))
1085 goto wait_for_sndbuf;
1087 skb = tcp_alloc_pskb(sk, select_size(sk, tp),
1088 0, sk->sk_allocation);
1090 goto wait_for_memory;
1093 * Check whether we can use HW checksum.
1095 if (sk->sk_route_caps &
1096 (NETIF_F_IP_CSUM | NETIF_F_NO_CSUM |
1098 skb->ip_summed = CHECKSUM_HW;
1100 skb_entail(sk, tp, skb);
1104 /* Try to append data to the end of skb. */
1108 /* Where to copy to? */
1109 if (skb_tailroom(skb) > 0) {
1110 /* We have some space in skb head. Superb! */
1111 if (copy > skb_tailroom(skb))
1112 copy = skb_tailroom(skb);
1113 if ((err = skb_add_data(skb, from, copy)) != 0)
1117 int i = skb_shinfo(skb)->nr_frags;
1118 struct page *page = TCP_PAGE(sk);
1119 int off = TCP_OFF(sk);
1121 if (can_coalesce(skb, i, page, off) &&
1123 /* We can extend the last page
1126 } else if (i == MAX_SKB_FRAGS ||
1128 !(sk->sk_route_caps & NETIF_F_SG))) {
1129 /* Need to add new fragment and cannot
1130 * do this because interface is non-SG,
1131 * or because all the page slots are
1133 tcp_mark_push(tp, skb);
1136 /* If page is cached, align
1137 * offset to L1 cache boundary
1139 off = (off + L1_CACHE_BYTES - 1) &
1140 ~(L1_CACHE_BYTES - 1);
1141 if (off == PAGE_SIZE) {
1143 TCP_PAGE(sk) = page = NULL;
1148 /* Allocate new cache page. */
1149 if (!(page = tcp_alloc_page(sk)))
1150 goto wait_for_memory;
1154 if (copy > PAGE_SIZE - off)
1155 copy = PAGE_SIZE - off;
1157 /* Time to copy data. We are close to
1159 err = tcp_copy_to_page(sk, from, skb, page,
1162 /* If this page was new, give it to the
1163 * socket so it does not get leaked.
1165 if (!TCP_PAGE(sk)) {
1166 TCP_PAGE(sk) = page;
1172 /* Update the skb. */
1174 skb_shinfo(skb)->frags[i - 1].size +=
1177 fill_page_desc(skb, i, page, off, copy);
1180 } else if (off + copy < PAGE_SIZE) {
1182 TCP_PAGE(sk) = page;
1186 TCP_OFF(sk) = off + copy;
1190 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
1192 tp->write_seq += copy;
1193 TCP_SKB_CB(skb)->end_seq += copy;
1197 if ((seglen -= copy) == 0 && iovlen == 0)
1200 if (skb->len != mss_now || (flags & MSG_OOB))
1203 if (forced_push(tp)) {
1204 tcp_mark_push(tp, skb);
1205 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
1206 } else if (skb == tp->send_head)
1207 tcp_push_one(sk, mss_now);
1211 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1214 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1216 if ((err = wait_for_tcp_memory(sk, &timeo)) != 0)
1219 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
1225 tcp_push(sk, tp, flags, mss_now, tp->nonagle);
1226 TCP_CHECK_TIMER(sk);
1232 if (tp->send_head == skb)
1233 tp->send_head = NULL;
1234 __skb_unlink(skb, skb->list);
1235 tcp_free_skb(sk, skb);
1242 err = tcp_error(sk, flags, err);
1243 TCP_CHECK_TIMER(sk);
1249 * Handle reading urgent data. BSD has very simple semantics for
1250 * this, no blocking and very strange errors 8)
1253 static int tcp_recv_urg(struct sock *sk, long timeo,
1254 struct msghdr *msg, int len, int flags,
1257 struct tcp_opt *tp = tcp_sk(sk);
1259 /* No URG data to read. */
1260 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1261 tp->urg_data == TCP_URG_READ)
1262 return -EINVAL; /* Yes this is right ! */
1264 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1267 if (tp->urg_data & TCP_URG_VALID) {
1269 char c = tp->urg_data;
1271 if (!(flags & MSG_PEEK))
1272 tp->urg_data = TCP_URG_READ;
1274 /* Read urgent data. */
1275 msg->msg_flags |= MSG_OOB;
1278 if (!(flags & MSG_TRUNC))
1279 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1282 msg->msg_flags |= MSG_TRUNC;
1284 return err ? -EFAULT : len;
1287 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1290 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
1291 * the available implementations agree in this case:
1292 * this call should never block, independent of the
1293 * blocking state of the socket.
1294 * Mike <pall@rz.uni-karlsruhe.de>
1299 /* Clean up the receive buffer for full frames taken by the user,
1300 * then send an ACK if necessary. COPIED is the number of bytes
1301 * tcp_recvmsg has given to the user so far, it speeds up the
1302 * calculation of whether or not we must ACK for the sake of
1305 static void cleanup_rbuf(struct sock *sk, int copied)
1307 struct tcp_opt *tp = tcp_sk(sk);
1308 int time_to_ack = 0;
1311 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1313 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
1316 if (tcp_ack_scheduled(tp)) {
1317 /* Delayed ACKs frequently hit locked sockets during bulk
1319 if (tp->ack.blocked ||
1320 /* Once-per-two-segments ACK was not sent by tcp_input.c */
1321 tp->rcv_nxt - tp->rcv_wup > tp->ack.rcv_mss ||
1323 * If this read emptied read buffer, we send ACK, if
1324 * connection is not bidirectional, user drained
1325 * receive buffer and there was a small segment
1328 (copied > 0 && (tp->ack.pending & TCP_ACK_PUSHED) &&
1329 !tp->ack.pingpong && !atomic_read(&sk->sk_rmem_alloc)))
1333 /* We send an ACK if we can now advertise a non-zero window
1334 * which has been raised "significantly".
1336 * Even if window raised up to infinity, do not send window open ACK
1337 * in states, where we will not receive more. It is useless.
1339 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1340 __u32 rcv_window_now = tcp_receive_window(tp);
1342 /* Optimize, __tcp_select_window() is not cheap. */
1343 if (2*rcv_window_now <= tp->window_clamp) {
1344 __u32 new_window = __tcp_select_window(sk);
1346 /* Send ACK now, if this read freed lots of space
1347 * in our buffer. Certainly, new_window is new window.
1348 * We can advertise it now, if it is not less than current one.
1349 * "Lots" means "at least twice" here.
1351 if (new_window && new_window >= 2 * rcv_window_now)
1359 static void tcp_prequeue_process(struct sock *sk)
1361 struct sk_buff *skb;
1362 struct tcp_opt *tp = tcp_sk(sk);
1364 NET_ADD_STATS_USER(TCPPrequeued, skb_queue_len(&tp->ucopy.prequeue));
1366 /* RX process wants to run with disabled BHs, though it is not
1369 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1370 sk->sk_backlog_rcv(sk, skb);
1373 /* Clear memory counter. */
1374 tp->ucopy.memory = 0;
1377 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1379 struct sk_buff *skb;
1382 skb_queue_walk(&sk->sk_receive_queue, skb) {
1383 offset = seq - TCP_SKB_CB(skb)->seq;
1386 if (offset < skb->len || skb->h.th->fin) {
1395 * This routine provides an alternative to tcp_recvmsg() for routines
1396 * that would like to handle copying from skbuffs directly in 'sendfile'
1399 * - It is assumed that the socket was locked by the caller.
1400 * - The routine does not block.
1401 * - At present, there is no support for reading OOB data
1402 * or for 'peeking' the socket using this routine
1403 * (although both would be easy to implement).
1405 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1406 sk_read_actor_t recv_actor)
1408 struct sk_buff *skb;
1409 struct tcp_opt *tp = tcp_sk(sk);
1410 u32 seq = tp->copied_seq;
1414 if (sk->sk_state == TCP_LISTEN)
1416 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1417 if (offset < skb->len) {
1420 len = skb->len - offset;
1421 /* Stop reading if we hit a patch of urgent data */
1423 u32 urg_offset = tp->urg_seq - seq;
1424 if (urg_offset < len)
1429 used = recv_actor(desc, skb, offset, len);
1435 if (offset != skb->len)
1438 if (skb->h.th->fin) {
1439 sk_eat_skb(sk, skb);
1443 sk_eat_skb(sk, skb);
1447 tp->copied_seq = seq;
1449 tcp_rcv_space_adjust(sk);
1451 /* Clean up data we have read: This will do ACK frames. */
1453 cleanup_rbuf(sk, copied);
1458 * This routine copies from a sock struct into the user buffer.
1460 * Technical note: in 2.3 we work on _locked_ socket, so that
1461 * tricks with *seq access order and skb->users are not required.
1462 * Probably, code can be easily improved even more.
1465 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1466 size_t len, int nonblock, int flags, int *addr_len)
1468 struct tcp_opt *tp = tcp_sk(sk);
1474 int target; /* Read at least this many bytes */
1476 struct task_struct *user_recv = NULL;
1480 TCP_CHECK_TIMER(sk);
1483 if (sk->sk_state == TCP_LISTEN)
1486 timeo = sock_rcvtimeo(sk, nonblock);
1488 /* Urgent data needs to be handled specially. */
1489 if (flags & MSG_OOB)
1492 seq = &tp->copied_seq;
1493 if (flags & MSG_PEEK) {
1494 peek_seq = tp->copied_seq;
1498 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1501 struct sk_buff *skb;
1504 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1505 if (tp->urg_data && tp->urg_seq == *seq) {
1508 if (signal_pending(current)) {
1509 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1514 /* Next get a buffer. */
1516 skb = skb_peek(&sk->sk_receive_queue);
1521 /* Now that we have two receive queues this
1524 if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1525 printk(KERN_INFO "recvmsg bug: copied %X "
1526 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1529 offset = *seq - TCP_SKB_CB(skb)->seq;
1532 if (offset < skb->len)
1536 BUG_TRAP(flags & MSG_PEEK);
1538 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1540 /* Well, if we have backlog, try to process it now yet. */
1542 if (copied >= target && !sk->sk_backlog.tail)
1547 sk->sk_state == TCP_CLOSE ||
1548 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1550 signal_pending(current) ||
1554 if (sock_flag(sk, SOCK_DONE))
1558 copied = sock_error(sk);
1562 if (sk->sk_shutdown & RCV_SHUTDOWN)
1565 if (sk->sk_state == TCP_CLOSE) {
1566 if (!sock_flag(sk, SOCK_DONE)) {
1567 /* This occurs when user tries to read
1568 * from never connected socket.
1581 if (signal_pending(current)) {
1582 copied = sock_intr_errno(timeo);
1587 cleanup_rbuf(sk, copied);
1589 if (tp->ucopy.task == user_recv) {
1590 /* Install new reader */
1591 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1592 user_recv = current;
1593 tp->ucopy.task = user_recv;
1594 tp->ucopy.iov = msg->msg_iov;
1597 tp->ucopy.len = len;
1599 BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1600 (flags & (MSG_PEEK | MSG_TRUNC)));
1602 /* Ugly... If prequeue is not empty, we have to
1603 * process it before releasing socket, otherwise
1604 * order will be broken at second iteration.
1605 * More elegant solution is required!!!
1607 * Look: we have the following (pseudo)queues:
1609 * 1. packets in flight
1614 * Each queue can be processed only if the next ones
1615 * are empty. At this point we have empty receive_queue.
1616 * But prequeue _can_ be not empty after 2nd iteration,
1617 * when we jumped to start of loop because backlog
1618 * processing added something to receive_queue.
1619 * We cannot release_sock(), because backlog contains
1620 * packets arrived _after_ prequeued ones.
1622 * Shortly, algorithm is clear --- to process all
1623 * the queues in order. We could make it more directly,
1624 * requeueing packets from backlog to prequeue, if
1625 * is not empty. It is more elegant, but eats cycles,
1628 if (skb_queue_len(&tp->ucopy.prequeue))
1631 /* __ Set realtime policy in scheduler __ */
1634 if (copied >= target) {
1635 /* Do not sleep, just process backlog. */
1639 sk_wait_data(sk, &timeo);
1644 /* __ Restore normal policy in scheduler __ */
1646 if ((chunk = len - tp->ucopy.len) != 0) {
1647 NET_ADD_STATS_USER(TCPDirectCopyFromBacklog, chunk);
1652 if (tp->rcv_nxt == tp->copied_seq &&
1653 skb_queue_len(&tp->ucopy.prequeue)) {
1655 tcp_prequeue_process(sk);
1657 if ((chunk = len - tp->ucopy.len) != 0) {
1658 NET_ADD_STATS_USER(TCPDirectCopyFromPrequeue, chunk);
1664 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1665 if (net_ratelimit())
1666 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1667 current->comm, current->pid);
1668 peek_seq = tp->copied_seq;
1673 /* Ok so how much can we use? */
1674 used = skb->len - offset;
1678 /* Do we have urgent data here? */
1680 u32 urg_offset = tp->urg_seq - *seq;
1681 if (urg_offset < used) {
1683 if (!sock_flag(sk, SOCK_URGINLINE)) {
1695 if (!(flags & MSG_TRUNC)) {
1696 err = skb_copy_datagram_iovec(skb, offset,
1697 msg->msg_iov, used);
1699 /* Exception. Bailout! */
1710 tcp_rcv_space_adjust(sk);
1713 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1715 tcp_fast_path_check(sk, tp);
1717 if (used + offset < skb->len)
1722 if (!(flags & MSG_PEEK))
1723 sk_eat_skb(sk, skb);
1727 /* Process the FIN. */
1729 if (!(flags & MSG_PEEK))
1730 sk_eat_skb(sk, skb);
1735 if (skb_queue_len(&tp->ucopy.prequeue)) {
1738 tp->ucopy.len = copied > 0 ? len : 0;
1740 tcp_prequeue_process(sk);
1742 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1743 NET_ADD_STATS_USER(TCPDirectCopyFromPrequeue, chunk);
1749 tp->ucopy.task = NULL;
1753 /* According to UNIX98, msg_name/msg_namelen are ignored
1754 * on connected socket. I was just happy when found this 8) --ANK
1757 /* Clean up data we have read: This will do ACK frames. */
1758 cleanup_rbuf(sk, copied);
1760 TCP_CHECK_TIMER(sk);
1765 TCP_CHECK_TIMER(sk);
1770 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1775 * State processing on a close. This implements the state shift for
1776 * sending our FIN frame. Note that we only send a FIN for some
1777 * states. A shutdown() may have already sent the FIN, or we may be
1781 static unsigned char new_state[16] = {
1782 /* current state: new state: action: */
1783 /* (Invalid) */ TCP_CLOSE,
1784 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1785 /* TCP_SYN_SENT */ TCP_CLOSE,
1786 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1787 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1,
1788 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2,
1789 /* TCP_TIME_WAIT */ TCP_CLOSE,
1790 /* TCP_CLOSE */ TCP_CLOSE,
1791 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN,
1792 /* TCP_LAST_ACK */ TCP_LAST_ACK,
1793 /* TCP_LISTEN */ TCP_CLOSE,
1794 /* TCP_CLOSING */ TCP_CLOSING,
1797 static int tcp_close_state(struct sock *sk)
1799 int next = (int)new_state[sk->sk_state];
1800 int ns = next & TCP_STATE_MASK;
1802 tcp_set_state(sk, ns);
1804 return next & TCP_ACTION_FIN;
1808 * Shutdown the sending side of a connection. Much like close except
1809 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1812 void tcp_shutdown(struct sock *sk, int how)
1814 /* We need to grab some memory, and put together a FIN,
1815 * and then put it into the queue to be sent.
1816 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1818 if (!(how & SEND_SHUTDOWN))
1821 /* If we've already sent a FIN, or it's a closed state, skip this. */
1822 if ((1 << sk->sk_state) &
1823 (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1824 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1825 /* Clear out any half completed packets. FIN if needed. */
1826 if (tcp_close_state(sk))
1833 * Return 1 if we still have things to send in our buffers.
1836 static inline int closing(struct sock *sk)
1838 return (1 << sk->sk_state) &
1839 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK);
1842 static __inline__ void tcp_kill_sk_queues(struct sock *sk)
1844 /* First the read buffer. */
1845 __skb_queue_purge(&sk->sk_receive_queue);
1847 /* Next, the error queue. */
1848 __skb_queue_purge(&sk->sk_error_queue);
1850 /* Next, the write queue. */
1851 BUG_TRAP(skb_queue_empty(&sk->sk_write_queue));
1853 /* Account for returned memory. */
1854 tcp_mem_reclaim(sk);
1856 BUG_TRAP(!sk->sk_wmem_queued);
1857 BUG_TRAP(!sk->sk_forward_alloc);
1859 /* It is _impossible_ for the backlog to contain anything
1860 * when we get here. All user references to this socket
1861 * have gone away, only the net layer knows can touch it.
1866 * At this point, there should be no process reference to this
1867 * socket, and thus no user references at all. Therefore we
1868 * can assume the socket waitqueue is inactive and nobody will
1869 * try to jump onto it.
1871 void tcp_destroy_sock(struct sock *sk)
1873 BUG_TRAP(sk->sk_state == TCP_CLOSE);
1874 BUG_TRAP(sock_flag(sk, SOCK_DEAD));
1876 /* It cannot be in hash table! */
1877 BUG_TRAP(sk_unhashed(sk));
1879 /* If it has not 0 inet_sk(sk)->num, it must be bound */
1880 BUG_TRAP(!inet_sk(sk)->num || tcp_sk(sk)->bind_hash);
1883 if (sk->sk_zapped) {
1884 printk(KERN_DEBUG "TCP: double destroy sk=%p\n", sk);
1890 sk->sk_prot->destroy(sk);
1892 tcp_kill_sk_queues(sk);
1894 xfrm_sk_free_policy(sk);
1896 #ifdef INET_REFCNT_DEBUG
1897 if (atomic_read(&sk->sk_refcnt) != 1) {
1898 printk(KERN_DEBUG "Destruction TCP %p delayed, c=%d\n",
1899 sk, atomic_read(&sk->sk_refcnt));
1903 atomic_dec(&tcp_orphan_count);
1907 void tcp_close(struct sock *sk, long timeout)
1909 struct sk_buff *skb;
1910 int data_was_unread = 0;
1913 sk->sk_shutdown = SHUTDOWN_MASK;
1915 if (sk->sk_state == TCP_LISTEN) {
1916 tcp_set_state(sk, TCP_CLOSE);
1919 tcp_listen_stop(sk);
1921 goto adjudge_to_death;
1924 /* We need to flush the recv. buffs. We do this only on the
1925 * descriptor close, not protocol-sourced closes, because the
1926 * reader process may not have drained the data yet!
1928 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1929 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1931 data_was_unread += len;
1935 tcp_mem_reclaim(sk);
1937 /* As outlined in draft-ietf-tcpimpl-prob-03.txt, section
1938 * 3.10, we send a RST here because data was lost. To
1939 * witness the awful effects of the old behavior of always
1940 * doing a FIN, run an older 2.1.x kernel or 2.0.x, start
1941 * a bulk GET in an FTP client, suspend the process, wait
1942 * for the client to advertise a zero window, then kill -9
1943 * the FTP client, wheee... Note: timeout is always zero
1946 if (data_was_unread) {
1947 /* Unread data was tossed, zap the connection. */
1948 NET_INC_STATS_USER(TCPAbortOnClose);
1949 tcp_set_state(sk, TCP_CLOSE);
1950 tcp_send_active_reset(sk, GFP_KERNEL);
1951 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1952 /* Check zero linger _after_ checking for unread data. */
1953 sk->sk_prot->disconnect(sk, 0);
1954 NET_INC_STATS_USER(TCPAbortOnData);
1955 } else if (tcp_close_state(sk)) {
1956 /* We FIN if the application ate all the data before
1957 * zapping the connection.
1960 /* RED-PEN. Formally speaking, we have broken TCP state
1961 * machine. State transitions:
1963 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1964 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1965 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1967 * are legal only when FIN has been sent (i.e. in window),
1968 * rather than queued out of window. Purists blame.
1970 * F.e. "RFC state" is ESTABLISHED,
1971 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1973 * The visible declinations are that sometimes
1974 * we enter time-wait state, when it is not required really
1975 * (harmless), do not send active resets, when they are
1976 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1977 * they look as CLOSING or LAST_ACK for Linux)
1978 * Probably, I missed some more holelets.
1985 struct task_struct *tsk = current;
1989 prepare_to_wait(sk->sk_sleep, &wait,
1990 TASK_INTERRUPTIBLE);
1994 timeout = schedule_timeout(timeout);
1996 } while (!signal_pending(tsk) && timeout);
1998 finish_wait(sk->sk_sleep, &wait);
2002 /* It is the last release_sock in its life. It will remove backlog. */
2006 /* Now socket is owned by kernel and we acquire BH lock
2007 to finish close. No need to check for user refs.
2011 BUG_TRAP(!sock_owned_by_user(sk));
2016 /* This is a (useful) BSD violating of the RFC. There is a
2017 * problem with TCP as specified in that the other end could
2018 * keep a socket open forever with no application left this end.
2019 * We use a 3 minute timeout (about the same as BSD) then kill
2020 * our end. If they send after that then tough - BUT: long enough
2021 * that we won't make the old 4*rto = almost no time - whoops
2024 * Nope, it was not mistake. It is really desired behaviour
2025 * f.e. on http servers, when such sockets are useless, but
2026 * consume significant resources. Let's do it with special
2027 * linger2 option. --ANK
2030 if (sk->sk_state == TCP_FIN_WAIT2) {
2031 struct tcp_opt *tp = tcp_sk(sk);
2032 if (tp->linger2 < 0) {
2033 tcp_set_state(sk, TCP_CLOSE);
2034 tcp_send_active_reset(sk, GFP_ATOMIC);
2035 NET_INC_STATS_BH(TCPAbortOnLinger);
2037 int tmo = tcp_fin_time(tp);
2039 if (tmo > TCP_TIMEWAIT_LEN) {
2040 tcp_reset_keepalive_timer(sk, tcp_fin_time(tp));
2042 atomic_inc(&tcp_orphan_count);
2043 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2048 if (sk->sk_state != TCP_CLOSE) {
2049 tcp_mem_reclaim(sk);
2050 if (atomic_read(&tcp_orphan_count) > sysctl_tcp_max_orphans ||
2051 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
2052 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) {
2053 if (net_ratelimit())
2054 printk(KERN_INFO "TCP: too many of orphaned "
2056 tcp_set_state(sk, TCP_CLOSE);
2057 tcp_send_active_reset(sk, GFP_ATOMIC);
2058 NET_INC_STATS_BH(TCPAbortOnMemory);
2061 atomic_inc(&tcp_orphan_count);
2063 if (sk->sk_state == TCP_CLOSE)
2064 tcp_destroy_sock(sk);
2065 /* Otherwise, socket is reprieved until protocol close. */
2073 /* These states need RST on ABORT according to RFC793 */
2075 static inline int tcp_need_reset(int state)
2077 return (1 << state) &
2078 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2079 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2082 int tcp_disconnect(struct sock *sk, int flags)
2084 struct inet_opt *inet = inet_sk(sk);
2085 struct tcp_opt *tp = tcp_sk(sk);
2087 int old_state = sk->sk_state;
2089 if (old_state != TCP_CLOSE)
2090 tcp_set_state(sk, TCP_CLOSE);
2092 /* ABORT function of RFC793 */
2093 if (old_state == TCP_LISTEN) {
2094 tcp_listen_stop(sk);
2095 } else if (tcp_need_reset(old_state) ||
2096 (tp->snd_nxt != tp->write_seq &&
2097 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2098 /* The last check adjusts for discrepance of Linux wrt. RFC
2101 tcp_send_active_reset(sk, gfp_any());
2102 sk->sk_err = ECONNRESET;
2103 } else if (old_state == TCP_SYN_SENT)
2104 sk->sk_err = ECONNRESET;
2106 tcp_clear_xmit_timers(sk);
2107 __skb_queue_purge(&sk->sk_receive_queue);
2108 tcp_writequeue_purge(sk);
2109 __skb_queue_purge(&tp->out_of_order_queue);
2113 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2114 inet_reset_saddr(sk);
2116 sk->sk_shutdown = 0;
2117 sock_reset_flag(sk, SOCK_DONE);
2119 if ((tp->write_seq += tp->max_window + 2) == 0)
2124 tp->packets_out = 0;
2125 tp->snd_ssthresh = 0x7fffffff;
2126 tp->snd_cwnd_cnt = 0;
2127 tcp_set_ca_state(tp, TCP_CA_Open);
2128 tcp_clear_retrans(tp);
2129 tcp_delack_init(tp);
2130 tp->send_head = NULL;
2135 BUG_TRAP(!inet->num || tp->bind_hash);
2137 sk->sk_error_report(sk);
2142 * Wait for an incoming connection, avoid race
2143 * conditions. This must be called with the socket locked.
2145 static int wait_for_connect(struct sock *sk, long timeo)
2147 struct tcp_opt *tp = tcp_sk(sk);
2152 * True wake-one mechanism for incoming connections: only
2153 * one process gets woken up, not the 'whole herd'.
2154 * Since we do not 'race & poll' for established sockets
2155 * anymore, the common case will execute the loop only once.
2157 * Subtle issue: "add_wait_queue_exclusive()" will be added
2158 * after any current non-exclusive waiters, and we know that
2159 * it will always _stay_ after any new non-exclusive waiters
2160 * because all non-exclusive waiters are added at the
2161 * beginning of the wait-queue. As such, it's ok to "drop"
2162 * our exclusiveness temporarily when we get woken up without
2163 * having to remove and re-insert us on the wait queue.
2166 prepare_to_wait_exclusive(sk->sk_sleep, &wait,
2167 TASK_INTERRUPTIBLE);
2169 if (!tp->accept_queue)
2170 timeo = schedule_timeout(timeo);
2173 if (tp->accept_queue)
2176 if (sk->sk_state != TCP_LISTEN)
2178 err = sock_intr_errno(timeo);
2179 if (signal_pending(current))
2185 finish_wait(sk->sk_sleep, &wait);
2190 * This will accept the next outstanding connection.
2193 struct sock *tcp_accept(struct sock *sk, int flags, int *err)
2195 struct tcp_opt *tp = tcp_sk(sk);
2196 struct open_request *req;
2202 /* We need to make sure that this socket is listening,
2203 * and that it has something pending.
2206 if (sk->sk_state != TCP_LISTEN)
2209 /* Find already established connection */
2210 if (!tp->accept_queue) {
2211 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
2213 /* If this is a non blocking socket don't sleep */
2218 error = wait_for_connect(sk, timeo);
2223 req = tp->accept_queue;
2224 if ((tp->accept_queue = req->dl_next) == NULL)
2225 tp->accept_queue_tail = NULL;
2228 sk_acceptq_removed(sk);
2229 tcp_openreq_fastfree(req);
2230 BUG_TRAP(newsk->sk_state != TCP_SYN_RECV);
2241 * Socket option code for TCP.
2243 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2246 struct tcp_opt *tp = tcp_sk(sk);
2250 if (level != SOL_TCP)
2251 return tp->af_specific->setsockopt(sk, level, optname,
2254 if (optlen < sizeof(int))
2257 if (get_user(val, (int __user *)optval))
2264 /* Values greater than interface MTU won't take effect. However
2265 * at the point when this call is done we typically don't yet
2266 * know which interface is going to be used */
2267 if (val < 8 || val > MAX_TCP_WINDOW) {
2276 /* TCP_NODELAY is weaker than TCP_CORK, so that
2277 * this option on corked socket is remembered, but
2278 * it is not activated until cork is cleared.
2280 * However, when TCP_NODELAY is set we make
2281 * an explicit push, which overrides even TCP_CORK
2282 * for currently queued segments.
2284 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2285 tcp_push_pending_frames(sk, tp);
2287 tp->nonagle &= ~TCP_NAGLE_OFF;
2292 /* When set indicates to always queue non-full frames.
2293 * Later the user clears this option and we transmit
2294 * any pending partial frames in the queue. This is
2295 * meant to be used alongside sendfile() to get properly
2296 * filled frames when the user (for example) must write
2297 * out headers with a write() call first and then use
2298 * sendfile to send out the data parts.
2300 * TCP_CORK can be set together with TCP_NODELAY and it is
2301 * stronger than TCP_NODELAY.
2304 tp->nonagle |= TCP_NAGLE_CORK;
2306 tp->nonagle &= ~TCP_NAGLE_CORK;
2307 if (tp->nonagle&TCP_NAGLE_OFF)
2308 tp->nonagle |= TCP_NAGLE_PUSH;
2309 tcp_push_pending_frames(sk, tp);
2314 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2317 tp->keepalive_time = val * HZ;
2318 if (sock_flag(sk, SOCK_KEEPOPEN) &&
2319 !((1 << sk->sk_state) &
2320 (TCPF_CLOSE | TCPF_LISTEN))) {
2321 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
2322 if (tp->keepalive_time > elapsed)
2323 elapsed = tp->keepalive_time - elapsed;
2326 tcp_reset_keepalive_timer(sk, elapsed);
2331 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2334 tp->keepalive_intvl = val * HZ;
2337 if (val < 1 || val > MAX_TCP_KEEPCNT)
2340 tp->keepalive_probes = val;
2343 if (val < 1 || val > MAX_TCP_SYNCNT)
2346 tp->syn_retries = val;
2352 else if (val > sysctl_tcp_fin_timeout / HZ)
2355 tp->linger2 = val * HZ;
2358 case TCP_DEFER_ACCEPT:
2359 tp->defer_accept = 0;
2361 /* Translate value in seconds to number of
2363 while (tp->defer_accept < 32 &&
2364 val > ((TCP_TIMEOUT_INIT / HZ) <<
2371 case TCP_WINDOW_CLAMP:
2373 if (sk->sk_state != TCP_CLOSE) {
2377 tp->window_clamp = 0;
2379 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2380 SOCK_MIN_RCVBUF / 2 : val;
2385 tp->ack.pingpong = 1;
2387 tp->ack.pingpong = 0;
2388 if ((1 << sk->sk_state) &
2389 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2390 tcp_ack_scheduled(tp)) {
2391 tp->ack.pending |= TCP_ACK_PUSHED;
2392 cleanup_rbuf(sk, 1);
2394 tp->ack.pingpong = 1;
2407 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2410 struct tcp_opt *tp = tcp_sk(sk);
2413 if (level != SOL_TCP)
2414 return tp->af_specific->getsockopt(sk, level, optname,
2417 if (get_user(len, optlen))
2420 len = min_t(unsigned int, len, sizeof(int));
2427 val = tp->mss_cache_std;
2428 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2432 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2435 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2438 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2441 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2444 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2447 val = tp->syn_retries ? : sysctl_tcp_syn_retries;
2452 val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2454 case TCP_DEFER_ACCEPT:
2455 val = !tp->defer_accept ? 0 : ((TCP_TIMEOUT_INIT / HZ) <<
2456 (tp->defer_accept - 1));
2458 case TCP_WINDOW_CLAMP:
2459 val = tp->window_clamp;
2462 struct tcp_info info;
2464 if (get_user(len, optlen))
2467 tcp_get_info(sk, &info);
2469 len = min_t(unsigned int, len, sizeof(info));
2470 if (put_user(len, optlen))
2472 if (copy_to_user(optval, &info, len))
2477 val = !tp->ack.pingpong;
2480 return -ENOPROTOOPT;
2483 if (put_user(len, optlen))
2485 if (copy_to_user(optval, &val, len))
2491 extern void __skb_cb_too_small_for_tcp(int, int);
2492 extern void tcpdiag_init(void);
2494 static __initdata unsigned long thash_entries;
2495 static int __init set_thash_entries(char *str)
2499 thash_entries = simple_strtoul(str, &str, 0);
2502 __setup("thash_entries=", set_thash_entries);
2504 void __init tcp_init(void)
2506 struct sk_buff *skb = NULL;
2510 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2511 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2514 tcp_openreq_cachep = kmem_cache_create("tcp_open_request",
2515 sizeof(struct open_request),
2516 0, SLAB_HWCACHE_ALIGN,
2518 if (!tcp_openreq_cachep)
2519 panic("tcp_init: Cannot alloc open_request cache.");
2521 tcp_bucket_cachep = kmem_cache_create("tcp_bind_bucket",
2522 sizeof(struct tcp_bind_bucket),
2523 0, SLAB_HWCACHE_ALIGN,
2525 if (!tcp_bucket_cachep)
2526 panic("tcp_init: Cannot alloc tcp_bind_bucket cache.");
2528 tcp_timewait_cachep = kmem_cache_create("tcp_tw_bucket",
2529 sizeof(struct tcp_tw_bucket),
2530 0, SLAB_HWCACHE_ALIGN,
2532 if (!tcp_timewait_cachep)
2533 panic("tcp_init: Cannot alloc tcp_tw_bucket cache.");
2535 /* Size and allocate the main established and bind bucket
2538 * The methodology is similar to that of the buffer cache.
2540 if (num_physpages >= (128 * 1024))
2541 goal = num_physpages >> (21 - PAGE_SHIFT);
2543 goal = num_physpages >> (23 - PAGE_SHIFT);
2546 goal = (thash_entries * sizeof(struct tcp_ehash_bucket)) >> PAGE_SHIFT;
2547 for (order = 0; (1UL << order) < goal; order++)
2550 tcp_ehash_size = (1UL << order) * PAGE_SIZE /
2551 sizeof(struct tcp_ehash_bucket);
2552 tcp_ehash_size >>= 1;
2553 while (tcp_ehash_size & (tcp_ehash_size - 1))
2555 tcp_ehash = (struct tcp_ehash_bucket *)
2556 __get_free_pages(GFP_ATOMIC, order);
2557 } while (!tcp_ehash && --order > 0);
2560 panic("Failed to allocate TCP established hash table\n");
2561 for (i = 0; i < (tcp_ehash_size << 1); i++) {
2562 tcp_ehash[i].lock = RW_LOCK_UNLOCKED;
2563 INIT_HLIST_HEAD(&tcp_ehash[i].chain);
2567 tcp_bhash_size = (1UL << order) * PAGE_SIZE /
2568 sizeof(struct tcp_bind_hashbucket);
2569 if ((tcp_bhash_size > (64 * 1024)) && order > 0)
2571 tcp_bhash = (struct tcp_bind_hashbucket *)
2572 __get_free_pages(GFP_ATOMIC, order);
2573 } while (!tcp_bhash && --order >= 0);
2576 panic("Failed to allocate TCP bind hash table\n");
2577 for (i = 0; i < tcp_bhash_size; i++) {
2578 tcp_bhash[i].lock = SPIN_LOCK_UNLOCKED;
2579 INIT_HLIST_HEAD(&tcp_bhash[i].chain);
2582 /* Try to be a bit smarter and adjust defaults depending
2583 * on available memory.
2586 sysctl_local_port_range[0] = 32768;
2587 sysctl_local_port_range[1] = 61000;
2588 sysctl_tcp_max_tw_buckets = 180000;
2589 sysctl_tcp_max_orphans = 4096 << (order - 4);
2590 sysctl_max_syn_backlog = 1024;
2591 } else if (order < 3) {
2592 sysctl_local_port_range[0] = 1024 * (3 - order);
2593 sysctl_tcp_max_tw_buckets >>= (3 - order);
2594 sysctl_tcp_max_orphans >>= (3 - order);
2595 sysctl_max_syn_backlog = 128;
2597 tcp_port_rover = sysctl_local_port_range[0] - 1;
2599 sysctl_tcp_mem[0] = 768 << order;
2600 sysctl_tcp_mem[1] = 1024 << order;
2601 sysctl_tcp_mem[2] = 1536 << order;
2604 sysctl_tcp_wmem[2] = 64 * 1024;
2605 sysctl_tcp_rmem[0] = PAGE_SIZE;
2606 sysctl_tcp_rmem[1] = 43689;
2607 sysctl_tcp_rmem[2] = 2 * 43689;
2610 printk(KERN_INFO "TCP: Hash tables configured "
2611 "(established %d bind %d)\n",
2612 tcp_ehash_size << 1, tcp_bhash_size);
2617 EXPORT_SYMBOL(__tcp_mem_reclaim);
2618 EXPORT_SYMBOL(sysctl_tcp_rmem);
2619 EXPORT_SYMBOL(sysctl_tcp_wmem);
2620 EXPORT_SYMBOL(tcp_accept);
2621 EXPORT_SYMBOL(tcp_close);
2622 EXPORT_SYMBOL(tcp_close_state);
2623 EXPORT_SYMBOL(tcp_destroy_sock);
2624 EXPORT_SYMBOL(tcp_disconnect);
2625 EXPORT_SYMBOL(tcp_getsockopt);
2626 EXPORT_SYMBOL(tcp_ioctl);
2627 EXPORT_SYMBOL(tcp_openreq_cachep);
2628 EXPORT_SYMBOL(tcp_poll);
2629 EXPORT_SYMBOL(tcp_read_sock);
2630 EXPORT_SYMBOL(tcp_recvmsg);
2631 EXPORT_SYMBOL(tcp_sendmsg);
2632 EXPORT_SYMBOL(tcp_sendpage);
2633 EXPORT_SYMBOL(tcp_setsockopt);
2634 EXPORT_SYMBOL(tcp_shutdown);
2635 EXPORT_SYMBOL(tcp_sockets_allocated);
2636 EXPORT_SYMBOL(tcp_statistics);
2637 EXPORT_SYMBOL(tcp_timewait_cachep);
2638 EXPORT_SYMBOL(tcp_write_space);