2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * Implementation of the Transmission Control Protocol(TCP).
8 * Version: $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Mark Evans, <evansmp@uhura.aston.ac.uk>
13 * Corey Minyard <wf-rch!minyard@relay.EU.net>
14 * Florian La Roche, <flla@stud.uni-sb.de>
15 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
16 * Linus Torvalds, <torvalds@cs.helsinki.fi>
17 * Alan Cox, <gw4pts@gw4pts.ampr.org>
18 * Matthew Dillon, <dillon@apollo.west.oic.com>
19 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
20 * Jorge Cwik, <jorge@laser.satlink.net>
23 * Alan Cox : Numerous verify_area() calls
24 * Alan Cox : Set the ACK bit on a reset
25 * Alan Cox : Stopped it crashing if it closed while
26 * sk->inuse=1 and was trying to connect
28 * Alan Cox : All icmp error handling was broken
29 * pointers passed where wrong and the
30 * socket was looked up backwards. Nobody
31 * tested any icmp error code obviously.
32 * Alan Cox : tcp_err() now handled properly. It
33 * wakes people on errors. poll
34 * behaves and the icmp error race
35 * has gone by moving it into sock.c
36 * Alan Cox : tcp_send_reset() fixed to work for
37 * everything not just packets for
39 * Alan Cox : tcp option processing.
40 * Alan Cox : Reset tweaked (still not 100%) [Had
42 * Herp Rosmanith : More reset fixes
43 * Alan Cox : No longer acks invalid rst frames.
44 * Acking any kind of RST is right out.
45 * Alan Cox : Sets an ignore me flag on an rst
46 * receive otherwise odd bits of prattle
48 * Alan Cox : Fixed another acking RST frame bug.
49 * Should stop LAN workplace lockups.
50 * Alan Cox : Some tidyups using the new skb list
52 * Alan Cox : sk->keepopen now seems to work
53 * Alan Cox : Pulls options out correctly on accepts
54 * Alan Cox : Fixed assorted sk->rqueue->next errors
55 * Alan Cox : PSH doesn't end a TCP read. Switched a
57 * Alan Cox : Tidied tcp_data to avoid a potential
59 * Alan Cox : Added some better commenting, as the
60 * tcp is hard to follow
61 * Alan Cox : Removed incorrect check for 20 * psh
62 * Michael O'Reilly : ack < copied bug fix.
63 * Johannes Stille : Misc tcp fixes (not all in yet).
64 * Alan Cox : FIN with no memory -> CRASH
65 * Alan Cox : Added socket option proto entries.
66 * Also added awareness of them to accept.
67 * Alan Cox : Added TCP options (SOL_TCP)
68 * Alan Cox : Switched wakeup calls to callbacks,
69 * so the kernel can layer network
71 * Alan Cox : Use ip_tos/ip_ttl settings.
72 * Alan Cox : Handle FIN (more) properly (we hope).
73 * Alan Cox : RST frames sent on unsynchronised
75 * Alan Cox : Put in missing check for SYN bit.
76 * Alan Cox : Added tcp_select_window() aka NET2E
77 * window non shrink trick.
78 * Alan Cox : Added a couple of small NET2E timer
80 * Charles Hedrick : TCP fixes
81 * Toomas Tamm : TCP window fixes
82 * Alan Cox : Small URG fix to rlogin ^C ack fight
83 * Charles Hedrick : Rewrote most of it to actually work
84 * Linus : Rewrote tcp_read() and URG handling
86 * Gerhard Koerting: Fixed some missing timer handling
87 * Matthew Dillon : Reworked TCP machine states as per RFC
88 * Gerhard Koerting: PC/TCP workarounds
89 * Adam Caldwell : Assorted timer/timing errors
90 * Matthew Dillon : Fixed another RST bug
91 * Alan Cox : Move to kernel side addressing changes.
92 * Alan Cox : Beginning work on TCP fastpathing
94 * Arnt Gulbrandsen: Turbocharged tcp_check() routine.
95 * Alan Cox : TCP fast path debugging
96 * Alan Cox : Window clamping
97 * Michael Riepe : Bug in tcp_check()
98 * Matt Dillon : More TCP improvements and RST bug fixes
99 * Matt Dillon : Yet more small nasties remove from the
100 * TCP code (Be very nice to this man if
101 * tcp finally works 100%) 8)
102 * Alan Cox : BSD accept semantics.
103 * Alan Cox : Reset on closedown bug.
104 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
105 * Michael Pall : Handle poll() after URG properly in
107 * Michael Pall : Undo the last fix in tcp_read_urg()
108 * (multi URG PUSH broke rlogin).
109 * Michael Pall : Fix the multi URG PUSH problem in
110 * tcp_readable(), poll() after URG
112 * Michael Pall : recv(...,MSG_OOB) never blocks in the
114 * Alan Cox : Changed the semantics of sk->socket to
115 * fix a race and a signal problem with
116 * accept() and async I/O.
117 * Alan Cox : Relaxed the rules on tcp_sendto().
118 * Yury Shevchuk : Really fixed accept() blocking problem.
119 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
120 * clients/servers which listen in on
122 * Alan Cox : Cleaned the above up and shrank it to
123 * a sensible code size.
124 * Alan Cox : Self connect lockup fix.
125 * Alan Cox : No connect to multicast.
126 * Ross Biro : Close unaccepted children on master
128 * Alan Cox : Reset tracing code.
129 * Alan Cox : Spurious resets on shutdown.
130 * Alan Cox : Giant 15 minute/60 second timer error
131 * Alan Cox : Small whoops in polling before an
133 * Alan Cox : Kept the state trace facility since
134 * it's handy for debugging.
135 * Alan Cox : More reset handler fixes.
136 * Alan Cox : Started rewriting the code based on
137 * the RFC's for other useful protocol
138 * references see: Comer, KA9Q NOS, and
139 * for a reference on the difference
140 * between specifications and how BSD
141 * works see the 4.4lite source.
142 * A.N.Kuznetsov : Don't time wait on completion of tidy
144 * Linus Torvalds : Fin/Shutdown & copied_seq changes.
145 * Linus Torvalds : Fixed BSD port reuse to work first syn
146 * Alan Cox : Reimplemented timers as per the RFC
147 * and using multiple timers for sanity.
148 * Alan Cox : Small bug fixes, and a lot of new
150 * Alan Cox : Fixed dual reader crash by locking
151 * the buffers (much like datagram.c)
152 * Alan Cox : Fixed stuck sockets in probe. A probe
153 * now gets fed up of retrying without
154 * (even a no space) answer.
155 * Alan Cox : Extracted closing code better
156 * Alan Cox : Fixed the closing state machine to
158 * Alan Cox : More 'per spec' fixes.
159 * Jorge Cwik : Even faster checksumming.
160 * Alan Cox : tcp_data() doesn't ack illegal PSH
161 * only frames. At least one pc tcp stack
163 * Alan Cox : Cache last socket.
164 * Alan Cox : Per route irtt.
165 * Matt Day : poll()->select() match BSD precisely on error
166 * Alan Cox : New buffers
167 * Marc Tamsky : Various sk->prot->retransmits and
168 * sk->retransmits misupdating fixed.
169 * Fixed tcp_write_timeout: stuck close,
170 * and TCP syn retries gets used now.
171 * Mark Yarvis : In tcp_read_wakeup(), don't send an
172 * ack if state is TCP_CLOSED.
173 * Alan Cox : Look up device on a retransmit - routes may
174 * change. Doesn't yet cope with MSS shrink right
176 * Marc Tamsky : Closing in closing fixes.
177 * Mike Shaver : RFC1122 verifications.
178 * Alan Cox : rcv_saddr errors.
179 * Alan Cox : Block double connect().
180 * Alan Cox : Small hooks for enSKIP.
181 * Alexey Kuznetsov: Path MTU discovery.
182 * Alan Cox : Support soft errors.
183 * Alan Cox : Fix MTU discovery pathological case
184 * when the remote claims no mtu!
185 * Marc Tamsky : TCP_CLOSE fix.
186 * Colin (G3TNE) : Send a reset on syn ack replies in
187 * window but wrong (fixes NT lpd problems)
188 * Pedro Roque : Better TCP window handling, delayed ack.
189 * Joerg Reuter : No modification of locked buffers in
190 * tcp_do_retransmit()
191 * Eric Schenk : Changed receiver side silly window
192 * avoidance algorithm to BSD style
193 * algorithm. This doubles throughput
194 * against machines running Solaris,
195 * and seems to result in general
197 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
198 * Willy Konynenberg : Transparent proxying support.
199 * Mike McLagan : Routing by source
200 * Keith Owens : Do proper merging with partial SKB's in
201 * tcp_do_sendmsg to avoid burstiness.
202 * Eric Schenk : Fix fast close down bug with
203 * shutdown() followed by close().
204 * Andi Kleen : Make poll agree with SIGIO
205 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
206 * lingertime == 0 (RFC 793 ABORT Call)
207 * Hirokazu Takahashi : Use copy_from_user() instead of
208 * csum_and_copy_from_user() if possible.
210 * This program is free software; you can redistribute it and/or
211 * modify it under the terms of the GNU General Public License
212 * as published by the Free Software Foundation; either version
213 * 2 of the License, or(at your option) any later version.
215 * Description of States:
217 * TCP_SYN_SENT sent a connection request, waiting for ack
219 * TCP_SYN_RECV received a connection request, sent ack,
220 * waiting for final ack in three-way handshake.
222 * TCP_ESTABLISHED connection established
224 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete
225 * transmission of remaining buffered data
227 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote
230 * TCP_CLOSING both sides have shutdown but we still have
231 * data we have to finish sending
233 * TCP_TIME_WAIT timeout to catch resent junk before entering
234 * closed, can only be entered from FIN_WAIT2
235 * or CLOSING. Required because the other end
236 * may not have gotten our last ACK causing it
237 * to retransmit the data packet (which we ignore)
239 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for
240 * us to finish writing our data and to shutdown
241 * (we have to close() to move on to LAST_ACK)
243 * TCP_LAST_ACK out side has shutdown after remote has
244 * shutdown. There may still be data in our
245 * buffer that we have to finish sending
247 * TCP_CLOSE socket is finished
250 #include <linux/module.h>
251 #include <linux/types.h>
252 #include <linux/fcntl.h>
253 #include <linux/poll.h>
254 #include <linux/init.h>
255 #include <linux/smp_lock.h>
256 #include <linux/fs.h>
257 #include <linux/random.h>
258 #include <linux/bootmem.h>
259 #include <linux/cache.h>
260 #include <linux/err.h>
261 #include <linux/crypto.h>
263 #include <net/icmp.h>
265 #include <net/xfrm.h>
267 #include <net/netdma.h>
269 #include <asm/uaccess.h>
270 #include <asm/ioctls.h>
272 int sysctl_tcp_fin_timeout __read_mostly
= TCP_FIN_TIMEOUT
;
274 DEFINE_SNMP_STAT(struct tcp_mib
, tcp_statistics
) __read_mostly
;
276 atomic_t tcp_orphan_count
= ATOMIC_INIT(0);
278 EXPORT_SYMBOL_GPL(tcp_orphan_count
);
280 int sysctl_tcp_mem
[3] __read_mostly
;
281 int sysctl_tcp_wmem
[3] __read_mostly
;
282 int sysctl_tcp_rmem
[3] __read_mostly
;
284 EXPORT_SYMBOL(sysctl_tcp_mem
);
285 EXPORT_SYMBOL(sysctl_tcp_rmem
);
286 EXPORT_SYMBOL(sysctl_tcp_wmem
);
288 atomic_t tcp_memory_allocated
; /* Current allocated memory. */
289 atomic_t tcp_sockets_allocated
; /* Current number of TCP sockets. */
291 EXPORT_SYMBOL(tcp_memory_allocated
);
292 EXPORT_SYMBOL(tcp_sockets_allocated
);
295 * Pressure flag: try to collapse.
296 * Technical note: it is used by multiple contexts non atomically.
297 * All the sk_stream_mem_schedule() is of this nature: accounting
298 * is strict, actions are advisory and have some latency.
300 int tcp_memory_pressure
;
302 EXPORT_SYMBOL(tcp_memory_pressure
);
304 void tcp_enter_memory_pressure(void)
306 if (!tcp_memory_pressure
) {
307 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES
);
308 tcp_memory_pressure
= 1;
312 EXPORT_SYMBOL(tcp_enter_memory_pressure
);
315 * Wait for a TCP event.
317 * Note that we don't need to lock the socket, as the upper poll layers
318 * take care of normal races (between the test and the event) and we don't
319 * go look at any of the socket buffers directly.
321 unsigned int tcp_poll(struct file
*file
, struct socket
*sock
, poll_table
*wait
)
324 struct sock
*sk
= sock
->sk
;
325 struct tcp_sock
*tp
= tcp_sk(sk
);
327 poll_wait(file
, sk
->sk_sleep
, wait
);
328 if (sk
->sk_state
== TCP_LISTEN
)
329 return inet_csk_listen_poll(sk
);
331 /* Socket is not locked. We are protected from async events
332 by poll logic and correct handling of state changes
333 made by another threads is impossible in any case.
341 * POLLHUP is certainly not done right. But poll() doesn't
342 * have a notion of HUP in just one direction, and for a
343 * socket the read side is more interesting.
345 * Some poll() documentation says that POLLHUP is incompatible
346 * with the POLLOUT/POLLWR flags, so somebody should check this
347 * all. But careful, it tends to be safer to return too many
348 * bits than too few, and you can easily break real applications
349 * if you don't tell them that something has hung up!
353 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
354 * our fs/select.c). It means that after we received EOF,
355 * poll always returns immediately, making impossible poll() on write()
356 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
357 * if and only if shutdown has been made in both directions.
358 * Actually, it is interesting to look how Solaris and DUX
359 * solve this dilemma. I would prefer, if PULLHUP were maskable,
360 * then we could set it on SND_SHUTDOWN. BTW examples given
361 * in Stevens' books assume exactly this behaviour, it explains
362 * why PULLHUP is incompatible with POLLOUT. --ANK
364 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
365 * blocking on fresh not-connected or disconnected socket. --ANK
367 if (sk
->sk_shutdown
== SHUTDOWN_MASK
|| sk
->sk_state
== TCP_CLOSE
)
369 if (sk
->sk_shutdown
& RCV_SHUTDOWN
)
370 mask
|= POLLIN
| POLLRDNORM
| POLLRDHUP
;
373 if ((1 << sk
->sk_state
) & ~(TCPF_SYN_SENT
| TCPF_SYN_RECV
)) {
374 /* Potential race condition. If read of tp below will
375 * escape above sk->sk_state, we can be illegally awaken
376 * in SYN_* states. */
377 if ((tp
->rcv_nxt
!= tp
->copied_seq
) &&
378 (tp
->urg_seq
!= tp
->copied_seq
||
379 tp
->rcv_nxt
!= tp
->copied_seq
+ 1 ||
380 sock_flag(sk
, SOCK_URGINLINE
) || !tp
->urg_data
))
381 mask
|= POLLIN
| POLLRDNORM
;
383 if (!(sk
->sk_shutdown
& SEND_SHUTDOWN
)) {
384 if (sk_stream_wspace(sk
) >= sk_stream_min_wspace(sk
)) {
385 mask
|= POLLOUT
| POLLWRNORM
;
386 } else { /* send SIGIO later */
387 set_bit(SOCK_ASYNC_NOSPACE
,
388 &sk
->sk_socket
->flags
);
389 set_bit(SOCK_NOSPACE
, &sk
->sk_socket
->flags
);
391 /* Race breaker. If space is freed after
392 * wspace test but before the flags are set,
393 * IO signal will be lost.
395 if (sk_stream_wspace(sk
) >= sk_stream_min_wspace(sk
))
396 mask
|= POLLOUT
| POLLWRNORM
;
400 if (tp
->urg_data
& TCP_URG_VALID
)
406 int tcp_ioctl(struct sock
*sk
, int cmd
, unsigned long arg
)
408 struct tcp_sock
*tp
= tcp_sk(sk
);
413 if (sk
->sk_state
== TCP_LISTEN
)
417 if ((1 << sk
->sk_state
) & (TCPF_SYN_SENT
| TCPF_SYN_RECV
))
419 else if (sock_flag(sk
, SOCK_URGINLINE
) ||
421 before(tp
->urg_seq
, tp
->copied_seq
) ||
422 !before(tp
->urg_seq
, tp
->rcv_nxt
)) {
423 answ
= tp
->rcv_nxt
- tp
->copied_seq
;
425 /* Subtract 1, if FIN is in queue. */
426 if (answ
&& !skb_queue_empty(&sk
->sk_receive_queue
))
428 ((struct sk_buff
*)sk
->sk_receive_queue
.prev
)->h
.th
->fin
;
430 answ
= tp
->urg_seq
- tp
->copied_seq
;
434 answ
= tp
->urg_data
&& tp
->urg_seq
== tp
->copied_seq
;
437 if (sk
->sk_state
== TCP_LISTEN
)
440 if ((1 << sk
->sk_state
) & (TCPF_SYN_SENT
| TCPF_SYN_RECV
))
443 answ
= tp
->write_seq
- tp
->snd_una
;
449 return put_user(answ
, (int __user
*)arg
);
452 static inline void tcp_mark_push(struct tcp_sock
*tp
, struct sk_buff
*skb
)
454 TCP_SKB_CB(skb
)->flags
|= TCPCB_FLAG_PSH
;
455 tp
->pushed_seq
= tp
->write_seq
;
458 static inline int forced_push(struct tcp_sock
*tp
)
460 return after(tp
->write_seq
, tp
->pushed_seq
+ (tp
->max_window
>> 1));
463 static inline void skb_entail(struct sock
*sk
, struct tcp_sock
*tp
,
466 struct tcp_skb_cb
*tcb
= TCP_SKB_CB(skb
);
469 tcb
->seq
= tcb
->end_seq
= tp
->write_seq
;
470 tcb
->flags
= TCPCB_FLAG_ACK
;
472 skb_header_release(skb
);
473 __skb_queue_tail(&sk
->sk_write_queue
, skb
);
474 sk_charge_skb(sk
, skb
);
475 if (!sk
->sk_send_head
)
476 sk
->sk_send_head
= skb
;
477 if (tp
->nonagle
& TCP_NAGLE_PUSH
)
478 tp
->nonagle
&= ~TCP_NAGLE_PUSH
;
481 static inline void tcp_mark_urg(struct tcp_sock
*tp
, int flags
,
484 if (flags
& MSG_OOB
) {
486 tp
->snd_up
= tp
->write_seq
;
487 TCP_SKB_CB(skb
)->sacked
|= TCPCB_URG
;
491 static inline void tcp_push(struct sock
*sk
, struct tcp_sock
*tp
, int flags
,
492 int mss_now
, int nonagle
)
494 if (sk
->sk_send_head
) {
495 struct sk_buff
*skb
= sk
->sk_write_queue
.prev
;
496 if (!(flags
& MSG_MORE
) || forced_push(tp
))
497 tcp_mark_push(tp
, skb
);
498 tcp_mark_urg(tp
, flags
, skb
);
499 __tcp_push_pending_frames(sk
, tp
, mss_now
,
500 (flags
& MSG_MORE
) ? TCP_NAGLE_CORK
: nonagle
);
504 static ssize_t
do_tcp_sendpages(struct sock
*sk
, struct page
**pages
, int poffset
,
505 size_t psize
, int flags
)
507 struct tcp_sock
*tp
= tcp_sk(sk
);
508 int mss_now
, size_goal
;
511 long timeo
= sock_sndtimeo(sk
, flags
& MSG_DONTWAIT
);
513 /* Wait for a connection to finish. */
514 if ((1 << sk
->sk_state
) & ~(TCPF_ESTABLISHED
| TCPF_CLOSE_WAIT
))
515 if ((err
= sk_stream_wait_connect(sk
, &timeo
)) != 0)
518 clear_bit(SOCK_ASYNC_NOSPACE
, &sk
->sk_socket
->flags
);
520 mss_now
= tcp_current_mss(sk
, !(flags
&MSG_OOB
));
521 size_goal
= tp
->xmit_size_goal
;
525 if (sk
->sk_err
|| (sk
->sk_shutdown
& SEND_SHUTDOWN
))
529 struct sk_buff
*skb
= sk
->sk_write_queue
.prev
;
530 struct page
*page
= pages
[poffset
/ PAGE_SIZE
];
531 int copy
, i
, can_coalesce
;
532 int offset
= poffset
% PAGE_SIZE
;
533 int size
= min_t(size_t, psize
, PAGE_SIZE
- offset
);
535 if (!sk
->sk_send_head
|| (copy
= size_goal
- skb
->len
) <= 0) {
537 if (!sk_stream_memory_free(sk
))
538 goto wait_for_sndbuf
;
540 skb
= sk_stream_alloc_pskb(sk
, 0, 0,
543 goto wait_for_memory
;
545 skb_entail(sk
, tp
, skb
);
552 i
= skb_shinfo(skb
)->nr_frags
;
553 can_coalesce
= skb_can_coalesce(skb
, i
, page
, offset
);
554 if (!can_coalesce
&& i
>= MAX_SKB_FRAGS
) {
555 tcp_mark_push(tp
, skb
);
558 if (!sk_stream_wmem_schedule(sk
, copy
))
559 goto wait_for_memory
;
562 skb_shinfo(skb
)->frags
[i
- 1].size
+= copy
;
565 skb_fill_page_desc(skb
, i
, page
, offset
, copy
);
569 skb
->data_len
+= copy
;
570 skb
->truesize
+= copy
;
571 sk
->sk_wmem_queued
+= copy
;
572 sk
->sk_forward_alloc
-= copy
;
573 skb
->ip_summed
= CHECKSUM_PARTIAL
;
574 tp
->write_seq
+= copy
;
575 TCP_SKB_CB(skb
)->end_seq
+= copy
;
576 skb_shinfo(skb
)->gso_segs
= 0;
579 TCP_SKB_CB(skb
)->flags
&= ~TCPCB_FLAG_PSH
;
583 if (!(psize
-= copy
))
586 if (skb
->len
< mss_now
|| (flags
& MSG_OOB
))
589 if (forced_push(tp
)) {
590 tcp_mark_push(tp
, skb
);
591 __tcp_push_pending_frames(sk
, tp
, mss_now
, TCP_NAGLE_PUSH
);
592 } else if (skb
== sk
->sk_send_head
)
593 tcp_push_one(sk
, mss_now
);
597 set_bit(SOCK_NOSPACE
, &sk
->sk_socket
->flags
);
600 tcp_push(sk
, tp
, flags
& ~MSG_MORE
, mss_now
, TCP_NAGLE_PUSH
);
602 if ((err
= sk_stream_wait_memory(sk
, &timeo
)) != 0)
605 mss_now
= tcp_current_mss(sk
, !(flags
&MSG_OOB
));
606 size_goal
= tp
->xmit_size_goal
;
611 tcp_push(sk
, tp
, flags
, mss_now
, tp
->nonagle
);
618 return sk_stream_error(sk
, flags
, err
);
621 ssize_t
tcp_sendpage(struct socket
*sock
, struct page
*page
, int offset
,
622 size_t size
, int flags
)
625 struct sock
*sk
= sock
->sk
;
627 if (!(sk
->sk_route_caps
& NETIF_F_SG
) ||
628 !(sk
->sk_route_caps
& NETIF_F_ALL_CSUM
))
629 return sock_no_sendpage(sock
, page
, offset
, size
, flags
);
633 res
= do_tcp_sendpages(sk
, &page
, offset
, size
, flags
);
639 #define TCP_PAGE(sk) (sk->sk_sndmsg_page)
640 #define TCP_OFF(sk) (sk->sk_sndmsg_off)
642 static inline int select_size(struct sock
*sk
, struct tcp_sock
*tp
)
644 int tmp
= tp
->mss_cache
;
646 if (sk
->sk_route_caps
& NETIF_F_SG
) {
650 int pgbreak
= SKB_MAX_HEAD(MAX_TCP_HEADER
);
652 if (tmp
>= pgbreak
&&
653 tmp
<= pgbreak
+ (MAX_SKB_FRAGS
- 1) * PAGE_SIZE
)
661 int tcp_sendmsg(struct kiocb
*iocb
, struct sock
*sk
, struct msghdr
*msg
,
665 struct tcp_sock
*tp
= tcp_sk(sk
);
668 int mss_now
, size_goal
;
675 flags
= msg
->msg_flags
;
676 timeo
= sock_sndtimeo(sk
, flags
& MSG_DONTWAIT
);
678 /* Wait for a connection to finish. */
679 if ((1 << sk
->sk_state
) & ~(TCPF_ESTABLISHED
| TCPF_CLOSE_WAIT
))
680 if ((err
= sk_stream_wait_connect(sk
, &timeo
)) != 0)
683 /* This should be in poll */
684 clear_bit(SOCK_ASYNC_NOSPACE
, &sk
->sk_socket
->flags
);
686 mss_now
= tcp_current_mss(sk
, !(flags
&MSG_OOB
));
687 size_goal
= tp
->xmit_size_goal
;
689 /* Ok commence sending. */
690 iovlen
= msg
->msg_iovlen
;
695 if (sk
->sk_err
|| (sk
->sk_shutdown
& SEND_SHUTDOWN
))
698 while (--iovlen
>= 0) {
699 int seglen
= iov
->iov_len
;
700 unsigned char __user
*from
= iov
->iov_base
;
707 skb
= sk
->sk_write_queue
.prev
;
709 if (!sk
->sk_send_head
||
710 (copy
= size_goal
- skb
->len
) <= 0) {
713 /* Allocate new segment. If the interface is SG,
714 * allocate skb fitting to single page.
716 if (!sk_stream_memory_free(sk
))
717 goto wait_for_sndbuf
;
719 skb
= sk_stream_alloc_pskb(sk
, select_size(sk
, tp
),
720 0, sk
->sk_allocation
);
722 goto wait_for_memory
;
725 * Check whether we can use HW checksum.
727 if (sk
->sk_route_caps
& NETIF_F_ALL_CSUM
)
728 skb
->ip_summed
= CHECKSUM_PARTIAL
;
730 skb_entail(sk
, tp
, skb
);
734 /* Try to append data to the end of skb. */
738 /* Where to copy to? */
739 if (skb_tailroom(skb
) > 0) {
740 /* We have some space in skb head. Superb! */
741 if (copy
> skb_tailroom(skb
))
742 copy
= skb_tailroom(skb
);
743 if ((err
= skb_add_data(skb
, from
, copy
)) != 0)
747 int i
= skb_shinfo(skb
)->nr_frags
;
748 struct page
*page
= TCP_PAGE(sk
);
749 int off
= TCP_OFF(sk
);
751 if (skb_can_coalesce(skb
, i
, page
, off
) &&
753 /* We can extend the last page
756 } else if (i
== MAX_SKB_FRAGS
||
758 !(sk
->sk_route_caps
& NETIF_F_SG
))) {
759 /* Need to add new fragment and cannot
760 * do this because interface is non-SG,
761 * or because all the page slots are
763 tcp_mark_push(tp
, skb
);
766 if (off
== PAGE_SIZE
) {
768 TCP_PAGE(sk
) = page
= NULL
;
774 if (copy
> PAGE_SIZE
- off
)
775 copy
= PAGE_SIZE
- off
;
777 if (!sk_stream_wmem_schedule(sk
, copy
))
778 goto wait_for_memory
;
781 /* Allocate new cache page. */
782 if (!(page
= sk_stream_alloc_page(sk
)))
783 goto wait_for_memory
;
786 /* Time to copy data. We are close to
788 err
= skb_copy_to_page(sk
, from
, skb
, page
,
791 /* If this page was new, give it to the
792 * socket so it does not get leaked.
801 /* Update the skb. */
803 skb_shinfo(skb
)->frags
[i
- 1].size
+=
806 skb_fill_page_desc(skb
, i
, page
, off
, copy
);
809 } else if (off
+ copy
< PAGE_SIZE
) {
815 TCP_OFF(sk
) = off
+ copy
;
819 TCP_SKB_CB(skb
)->flags
&= ~TCPCB_FLAG_PSH
;
821 tp
->write_seq
+= copy
;
822 TCP_SKB_CB(skb
)->end_seq
+= copy
;
823 skb_shinfo(skb
)->gso_segs
= 0;
827 if ((seglen
-= copy
) == 0 && iovlen
== 0)
830 if (skb
->len
< mss_now
|| (flags
& MSG_OOB
))
833 if (forced_push(tp
)) {
834 tcp_mark_push(tp
, skb
);
835 __tcp_push_pending_frames(sk
, tp
, mss_now
, TCP_NAGLE_PUSH
);
836 } else if (skb
== sk
->sk_send_head
)
837 tcp_push_one(sk
, mss_now
);
841 set_bit(SOCK_NOSPACE
, &sk
->sk_socket
->flags
);
844 tcp_push(sk
, tp
, flags
& ~MSG_MORE
, mss_now
, TCP_NAGLE_PUSH
);
846 if ((err
= sk_stream_wait_memory(sk
, &timeo
)) != 0)
849 mss_now
= tcp_current_mss(sk
, !(flags
&MSG_OOB
));
850 size_goal
= tp
->xmit_size_goal
;
856 tcp_push(sk
, tp
, flags
, mss_now
, tp
->nonagle
);
863 if (sk
->sk_send_head
== skb
)
864 sk
->sk_send_head
= NULL
;
865 __skb_unlink(skb
, &sk
->sk_write_queue
);
866 sk_stream_free_skb(sk
, skb
);
873 err
= sk_stream_error(sk
, flags
, err
);
880 * Handle reading urgent data. BSD has very simple semantics for
881 * this, no blocking and very strange errors 8)
884 static int tcp_recv_urg(struct sock
*sk
, long timeo
,
885 struct msghdr
*msg
, int len
, int flags
,
888 struct tcp_sock
*tp
= tcp_sk(sk
);
890 /* No URG data to read. */
891 if (sock_flag(sk
, SOCK_URGINLINE
) || !tp
->urg_data
||
892 tp
->urg_data
== TCP_URG_READ
)
893 return -EINVAL
; /* Yes this is right ! */
895 if (sk
->sk_state
== TCP_CLOSE
&& !sock_flag(sk
, SOCK_DONE
))
898 if (tp
->urg_data
& TCP_URG_VALID
) {
900 char c
= tp
->urg_data
;
902 if (!(flags
& MSG_PEEK
))
903 tp
->urg_data
= TCP_URG_READ
;
905 /* Read urgent data. */
906 msg
->msg_flags
|= MSG_OOB
;
909 if (!(flags
& MSG_TRUNC
))
910 err
= memcpy_toiovec(msg
->msg_iov
, &c
, 1);
913 msg
->msg_flags
|= MSG_TRUNC
;
915 return err
? -EFAULT
: len
;
918 if (sk
->sk_state
== TCP_CLOSE
|| (sk
->sk_shutdown
& RCV_SHUTDOWN
))
921 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
922 * the available implementations agree in this case:
923 * this call should never block, independent of the
924 * blocking state of the socket.
925 * Mike <pall@rz.uni-karlsruhe.de>
930 /* Clean up the receive buffer for full frames taken by the user,
931 * then send an ACK if necessary. COPIED is the number of bytes
932 * tcp_recvmsg has given to the user so far, it speeds up the
933 * calculation of whether or not we must ACK for the sake of
936 void tcp_cleanup_rbuf(struct sock
*sk
, int copied
)
938 struct tcp_sock
*tp
= tcp_sk(sk
);
942 struct sk_buff
*skb
= skb_peek(&sk
->sk_receive_queue
);
944 BUG_TRAP(!skb
|| before(tp
->copied_seq
, TCP_SKB_CB(skb
)->end_seq
));
947 if (inet_csk_ack_scheduled(sk
)) {
948 const struct inet_connection_sock
*icsk
= inet_csk(sk
);
949 /* Delayed ACKs frequently hit locked sockets during bulk
951 if (icsk
->icsk_ack
.blocked
||
952 /* Once-per-two-segments ACK was not sent by tcp_input.c */
953 tp
->rcv_nxt
- tp
->rcv_wup
> icsk
->icsk_ack
.rcv_mss
||
955 * If this read emptied read buffer, we send ACK, if
956 * connection is not bidirectional, user drained
957 * receive buffer and there was a small segment
961 ((icsk
->icsk_ack
.pending
& ICSK_ACK_PUSHED2
) ||
962 ((icsk
->icsk_ack
.pending
& ICSK_ACK_PUSHED
) &&
963 !icsk
->icsk_ack
.pingpong
)) &&
964 !atomic_read(&sk
->sk_rmem_alloc
)))
968 /* We send an ACK if we can now advertise a non-zero window
969 * which has been raised "significantly".
971 * Even if window raised up to infinity, do not send window open ACK
972 * in states, where we will not receive more. It is useless.
974 if (copied
> 0 && !time_to_ack
&& !(sk
->sk_shutdown
& RCV_SHUTDOWN
)) {
975 __u32 rcv_window_now
= tcp_receive_window(tp
);
977 /* Optimize, __tcp_select_window() is not cheap. */
978 if (2*rcv_window_now
<= tp
->window_clamp
) {
979 __u32 new_window
= __tcp_select_window(sk
);
981 /* Send ACK now, if this read freed lots of space
982 * in our buffer. Certainly, new_window is new window.
983 * We can advertise it now, if it is not less than current one.
984 * "Lots" means "at least twice" here.
986 if (new_window
&& new_window
>= 2 * rcv_window_now
)
994 static void tcp_prequeue_process(struct sock
*sk
)
997 struct tcp_sock
*tp
= tcp_sk(sk
);
999 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED
);
1001 /* RX process wants to run with disabled BHs, though it is not
1004 while ((skb
= __skb_dequeue(&tp
->ucopy
.prequeue
)) != NULL
)
1005 sk
->sk_backlog_rcv(sk
, skb
);
1008 /* Clear memory counter. */
1009 tp
->ucopy
.memory
= 0;
1012 static inline struct sk_buff
*tcp_recv_skb(struct sock
*sk
, u32 seq
, u32
*off
)
1014 struct sk_buff
*skb
;
1017 skb_queue_walk(&sk
->sk_receive_queue
, skb
) {
1018 offset
= seq
- TCP_SKB_CB(skb
)->seq
;
1021 if (offset
< skb
->len
|| skb
->h
.th
->fin
) {
1030 * This routine provides an alternative to tcp_recvmsg() for routines
1031 * that would like to handle copying from skbuffs directly in 'sendfile'
1034 * - It is assumed that the socket was locked by the caller.
1035 * - The routine does not block.
1036 * - At present, there is no support for reading OOB data
1037 * or for 'peeking' the socket using this routine
1038 * (although both would be easy to implement).
1040 int tcp_read_sock(struct sock
*sk
, read_descriptor_t
*desc
,
1041 sk_read_actor_t recv_actor
)
1043 struct sk_buff
*skb
;
1044 struct tcp_sock
*tp
= tcp_sk(sk
);
1045 u32 seq
= tp
->copied_seq
;
1049 if (sk
->sk_state
== TCP_LISTEN
)
1051 while ((skb
= tcp_recv_skb(sk
, seq
, &offset
)) != NULL
) {
1052 if (offset
< skb
->len
) {
1055 len
= skb
->len
- offset
;
1056 /* Stop reading if we hit a patch of urgent data */
1058 u32 urg_offset
= tp
->urg_seq
- seq
;
1059 if (urg_offset
< len
)
1064 used
= recv_actor(desc
, skb
, offset
, len
);
1070 if (offset
!= skb
->len
)
1073 if (skb
->h
.th
->fin
) {
1074 sk_eat_skb(sk
, skb
, 0);
1078 sk_eat_skb(sk
, skb
, 0);
1082 tp
->copied_seq
= seq
;
1084 tcp_rcv_space_adjust(sk
);
1086 /* Clean up data we have read: This will do ACK frames. */
1088 tcp_cleanup_rbuf(sk
, copied
);
1093 * This routine copies from a sock struct into the user buffer.
1095 * Technical note: in 2.3 we work on _locked_ socket, so that
1096 * tricks with *seq access order and skb->users are not required.
1097 * Probably, code can be easily improved even more.
1100 int tcp_recvmsg(struct kiocb
*iocb
, struct sock
*sk
, struct msghdr
*msg
,
1101 size_t len
, int nonblock
, int flags
, int *addr_len
)
1103 struct tcp_sock
*tp
= tcp_sk(sk
);
1109 int target
; /* Read at least this many bytes */
1111 struct task_struct
*user_recv
= NULL
;
1112 int copied_early
= 0;
1116 TCP_CHECK_TIMER(sk
);
1119 if (sk
->sk_state
== TCP_LISTEN
)
1122 timeo
= sock_rcvtimeo(sk
, nonblock
);
1124 /* Urgent data needs to be handled specially. */
1125 if (flags
& MSG_OOB
)
1128 seq
= &tp
->copied_seq
;
1129 if (flags
& MSG_PEEK
) {
1130 peek_seq
= tp
->copied_seq
;
1134 target
= sock_rcvlowat(sk
, flags
& MSG_WAITALL
, len
);
1136 #ifdef CONFIG_NET_DMA
1137 tp
->ucopy
.dma_chan
= NULL
;
1139 if ((len
> sysctl_tcp_dma_copybreak
) && !(flags
& MSG_PEEK
) &&
1140 !sysctl_tcp_low_latency
&& __get_cpu_var(softnet_data
).net_dma
) {
1141 preempt_enable_no_resched();
1142 tp
->ucopy
.pinned_list
= dma_pin_iovec_pages(msg
->msg_iov
, len
);
1144 preempt_enable_no_resched();
1148 struct sk_buff
*skb
;
1151 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1152 if (tp
->urg_data
&& tp
->urg_seq
== *seq
) {
1155 if (signal_pending(current
)) {
1156 copied
= timeo
? sock_intr_errno(timeo
) : -EAGAIN
;
1161 /* Next get a buffer. */
1163 skb
= skb_peek(&sk
->sk_receive_queue
);
1168 /* Now that we have two receive queues this
1171 if (before(*seq
, TCP_SKB_CB(skb
)->seq
)) {
1172 printk(KERN_INFO
"recvmsg bug: copied %X "
1173 "seq %X\n", *seq
, TCP_SKB_CB(skb
)->seq
);
1176 offset
= *seq
- TCP_SKB_CB(skb
)->seq
;
1179 if (offset
< skb
->len
)
1183 BUG_TRAP(flags
& MSG_PEEK
);
1185 } while (skb
!= (struct sk_buff
*)&sk
->sk_receive_queue
);
1187 /* Well, if we have backlog, try to process it now yet. */
1189 if (copied
>= target
&& !sk
->sk_backlog
.tail
)
1194 sk
->sk_state
== TCP_CLOSE
||
1195 (sk
->sk_shutdown
& RCV_SHUTDOWN
) ||
1197 signal_pending(current
) ||
1201 if (sock_flag(sk
, SOCK_DONE
))
1205 copied
= sock_error(sk
);
1209 if (sk
->sk_shutdown
& RCV_SHUTDOWN
)
1212 if (sk
->sk_state
== TCP_CLOSE
) {
1213 if (!sock_flag(sk
, SOCK_DONE
)) {
1214 /* This occurs when user tries to read
1215 * from never connected socket.
1228 if (signal_pending(current
)) {
1229 copied
= sock_intr_errno(timeo
);
1234 tcp_cleanup_rbuf(sk
, copied
);
1236 if (!sysctl_tcp_low_latency
&& tp
->ucopy
.task
== user_recv
) {
1237 /* Install new reader */
1238 if (!user_recv
&& !(flags
& (MSG_TRUNC
| MSG_PEEK
))) {
1239 user_recv
= current
;
1240 tp
->ucopy
.task
= user_recv
;
1241 tp
->ucopy
.iov
= msg
->msg_iov
;
1244 tp
->ucopy
.len
= len
;
1246 BUG_TRAP(tp
->copied_seq
== tp
->rcv_nxt
||
1247 (flags
& (MSG_PEEK
| MSG_TRUNC
)));
1249 /* Ugly... If prequeue is not empty, we have to
1250 * process it before releasing socket, otherwise
1251 * order will be broken at second iteration.
1252 * More elegant solution is required!!!
1254 * Look: we have the following (pseudo)queues:
1256 * 1. packets in flight
1261 * Each queue can be processed only if the next ones
1262 * are empty. At this point we have empty receive_queue.
1263 * But prequeue _can_ be not empty after 2nd iteration,
1264 * when we jumped to start of loop because backlog
1265 * processing added something to receive_queue.
1266 * We cannot release_sock(), because backlog contains
1267 * packets arrived _after_ prequeued ones.
1269 * Shortly, algorithm is clear --- to process all
1270 * the queues in order. We could make it more directly,
1271 * requeueing packets from backlog to prequeue, if
1272 * is not empty. It is more elegant, but eats cycles,
1275 if (!skb_queue_empty(&tp
->ucopy
.prequeue
))
1278 /* __ Set realtime policy in scheduler __ */
1281 if (copied
>= target
) {
1282 /* Do not sleep, just process backlog. */
1286 sk_wait_data(sk
, &timeo
);
1288 #ifdef CONFIG_NET_DMA
1289 tp
->ucopy
.wakeup
= 0;
1295 /* __ Restore normal policy in scheduler __ */
1297 if ((chunk
= len
- tp
->ucopy
.len
) != 0) {
1298 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG
, chunk
);
1303 if (tp
->rcv_nxt
== tp
->copied_seq
&&
1304 !skb_queue_empty(&tp
->ucopy
.prequeue
)) {
1306 tcp_prequeue_process(sk
);
1308 if ((chunk
= len
- tp
->ucopy
.len
) != 0) {
1309 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE
, chunk
);
1315 if ((flags
& MSG_PEEK
) && peek_seq
!= tp
->copied_seq
) {
1316 if (net_ratelimit())
1317 printk(KERN_DEBUG
"TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1318 current
->comm
, current
->pid
);
1319 peek_seq
= tp
->copied_seq
;
1324 /* Ok so how much can we use? */
1325 used
= skb
->len
- offset
;
1329 /* Do we have urgent data here? */
1331 u32 urg_offset
= tp
->urg_seq
- *seq
;
1332 if (urg_offset
< used
) {
1334 if (!sock_flag(sk
, SOCK_URGINLINE
)) {
1346 if (!(flags
& MSG_TRUNC
)) {
1347 #ifdef CONFIG_NET_DMA
1348 if (!tp
->ucopy
.dma_chan
&& tp
->ucopy
.pinned_list
)
1349 tp
->ucopy
.dma_chan
= get_softnet_dma();
1351 if (tp
->ucopy
.dma_chan
) {
1352 tp
->ucopy
.dma_cookie
= dma_skb_copy_datagram_iovec(
1353 tp
->ucopy
.dma_chan
, skb
, offset
,
1355 tp
->ucopy
.pinned_list
);
1357 if (tp
->ucopy
.dma_cookie
< 0) {
1359 printk(KERN_ALERT
"dma_cookie < 0\n");
1361 /* Exception. Bailout! */
1366 if ((offset
+ used
) == skb
->len
)
1372 err
= skb_copy_datagram_iovec(skb
, offset
,
1373 msg
->msg_iov
, used
);
1375 /* Exception. Bailout! */
1387 tcp_rcv_space_adjust(sk
);
1390 if (tp
->urg_data
&& after(tp
->copied_seq
, tp
->urg_seq
)) {
1392 tcp_fast_path_check(sk
, tp
);
1394 if (used
+ offset
< skb
->len
)
1399 if (!(flags
& MSG_PEEK
)) {
1400 sk_eat_skb(sk
, skb
, copied_early
);
1406 /* Process the FIN. */
1408 if (!(flags
& MSG_PEEK
)) {
1409 sk_eat_skb(sk
, skb
, copied_early
);
1416 if (!skb_queue_empty(&tp
->ucopy
.prequeue
)) {
1419 tp
->ucopy
.len
= copied
> 0 ? len
: 0;
1421 tcp_prequeue_process(sk
);
1423 if (copied
> 0 && (chunk
= len
- tp
->ucopy
.len
) != 0) {
1424 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE
, chunk
);
1430 tp
->ucopy
.task
= NULL
;
1434 #ifdef CONFIG_NET_DMA
1435 if (tp
->ucopy
.dma_chan
) {
1436 struct sk_buff
*skb
;
1437 dma_cookie_t done
, used
;
1439 dma_async_memcpy_issue_pending(tp
->ucopy
.dma_chan
);
1441 while (dma_async_memcpy_complete(tp
->ucopy
.dma_chan
,
1442 tp
->ucopy
.dma_cookie
, &done
,
1443 &used
) == DMA_IN_PROGRESS
) {
1444 /* do partial cleanup of sk_async_wait_queue */
1445 while ((skb
= skb_peek(&sk
->sk_async_wait_queue
)) &&
1446 (dma_async_is_complete(skb
->dma_cookie
, done
,
1447 used
) == DMA_SUCCESS
)) {
1448 __skb_dequeue(&sk
->sk_async_wait_queue
);
1453 /* Safe to free early-copied skbs now */
1454 __skb_queue_purge(&sk
->sk_async_wait_queue
);
1455 dma_chan_put(tp
->ucopy
.dma_chan
);
1456 tp
->ucopy
.dma_chan
= NULL
;
1458 if (tp
->ucopy
.pinned_list
) {
1459 dma_unpin_iovec_pages(tp
->ucopy
.pinned_list
);
1460 tp
->ucopy
.pinned_list
= NULL
;
1464 /* According to UNIX98, msg_name/msg_namelen are ignored
1465 * on connected socket. I was just happy when found this 8) --ANK
1468 /* Clean up data we have read: This will do ACK frames. */
1469 tcp_cleanup_rbuf(sk
, copied
);
1471 TCP_CHECK_TIMER(sk
);
1476 TCP_CHECK_TIMER(sk
);
1481 err
= tcp_recv_urg(sk
, timeo
, msg
, len
, flags
, addr_len
);
1486 * State processing on a close. This implements the state shift for
1487 * sending our FIN frame. Note that we only send a FIN for some
1488 * states. A shutdown() may have already sent the FIN, or we may be
1492 static const unsigned char new_state
[16] = {
1493 /* current state: new state: action: */
1494 /* (Invalid) */ TCP_CLOSE
,
1495 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1
| TCP_ACTION_FIN
,
1496 /* TCP_SYN_SENT */ TCP_CLOSE
,
1497 /* TCP_SYN_RECV */ TCP_FIN_WAIT1
| TCP_ACTION_FIN
,
1498 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1
,
1499 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2
,
1500 /* TCP_TIME_WAIT */ TCP_CLOSE
,
1501 /* TCP_CLOSE */ TCP_CLOSE
,
1502 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK
| TCP_ACTION_FIN
,
1503 /* TCP_LAST_ACK */ TCP_LAST_ACK
,
1504 /* TCP_LISTEN */ TCP_CLOSE
,
1505 /* TCP_CLOSING */ TCP_CLOSING
,
1508 static int tcp_close_state(struct sock
*sk
)
1510 int next
= (int)new_state
[sk
->sk_state
];
1511 int ns
= next
& TCP_STATE_MASK
;
1513 tcp_set_state(sk
, ns
);
1515 return next
& TCP_ACTION_FIN
;
1519 * Shutdown the sending side of a connection. Much like close except
1520 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1523 void tcp_shutdown(struct sock
*sk
, int how
)
1525 /* We need to grab some memory, and put together a FIN,
1526 * and then put it into the queue to be sent.
1527 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1529 if (!(how
& SEND_SHUTDOWN
))
1532 /* If we've already sent a FIN, or it's a closed state, skip this. */
1533 if ((1 << sk
->sk_state
) &
1534 (TCPF_ESTABLISHED
| TCPF_SYN_SENT
|
1535 TCPF_SYN_RECV
| TCPF_CLOSE_WAIT
)) {
1536 /* Clear out any half completed packets. FIN if needed. */
1537 if (tcp_close_state(sk
))
1542 void tcp_close(struct sock
*sk
, long timeout
)
1544 struct sk_buff
*skb
;
1545 int data_was_unread
= 0;
1549 sk
->sk_shutdown
= SHUTDOWN_MASK
;
1551 if (sk
->sk_state
== TCP_LISTEN
) {
1552 tcp_set_state(sk
, TCP_CLOSE
);
1555 inet_csk_listen_stop(sk
);
1557 goto adjudge_to_death
;
1560 /* We need to flush the recv. buffs. We do this only on the
1561 * descriptor close, not protocol-sourced closes, because the
1562 * reader process may not have drained the data yet!
1564 while ((skb
= __skb_dequeue(&sk
->sk_receive_queue
)) != NULL
) {
1565 u32 len
= TCP_SKB_CB(skb
)->end_seq
- TCP_SKB_CB(skb
)->seq
-
1567 data_was_unread
+= len
;
1571 sk_stream_mem_reclaim(sk
);
1573 /* As outlined in draft-ietf-tcpimpl-prob-03.txt, section
1574 * 3.10, we send a RST here because data was lost. To
1575 * witness the awful effects of the old behavior of always
1576 * doing a FIN, run an older 2.1.x kernel or 2.0.x, start
1577 * a bulk GET in an FTP client, suspend the process, wait
1578 * for the client to advertise a zero window, then kill -9
1579 * the FTP client, wheee... Note: timeout is always zero
1582 if (data_was_unread
) {
1583 /* Unread data was tossed, zap the connection. */
1584 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE
);
1585 tcp_set_state(sk
, TCP_CLOSE
);
1586 tcp_send_active_reset(sk
, GFP_KERNEL
);
1587 } else if (sock_flag(sk
, SOCK_LINGER
) && !sk
->sk_lingertime
) {
1588 /* Check zero linger _after_ checking for unread data. */
1589 sk
->sk_prot
->disconnect(sk
, 0);
1590 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA
);
1591 } else if (tcp_close_state(sk
)) {
1592 /* We FIN if the application ate all the data before
1593 * zapping the connection.
1596 /* RED-PEN. Formally speaking, we have broken TCP state
1597 * machine. State transitions:
1599 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1600 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1601 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1603 * are legal only when FIN has been sent (i.e. in window),
1604 * rather than queued out of window. Purists blame.
1606 * F.e. "RFC state" is ESTABLISHED,
1607 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1609 * The visible declinations are that sometimes
1610 * we enter time-wait state, when it is not required really
1611 * (harmless), do not send active resets, when they are
1612 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1613 * they look as CLOSING or LAST_ACK for Linux)
1614 * Probably, I missed some more holelets.
1620 sk_stream_wait_close(sk
, timeout
);
1623 state
= sk
->sk_state
;
1626 atomic_inc(sk
->sk_prot
->orphan_count
);
1628 /* It is the last release_sock in its life. It will remove backlog. */
1632 /* Now socket is owned by kernel and we acquire BH lock
1633 to finish close. No need to check for user refs.
1637 BUG_TRAP(!sock_owned_by_user(sk
));
1639 /* Have we already been destroyed by a softirq or backlog? */
1640 if (state
!= TCP_CLOSE
&& sk
->sk_state
== TCP_CLOSE
)
1643 /* This is a (useful) BSD violating of the RFC. There is a
1644 * problem with TCP as specified in that the other end could
1645 * keep a socket open forever with no application left this end.
1646 * We use a 3 minute timeout (about the same as BSD) then kill
1647 * our end. If they send after that then tough - BUT: long enough
1648 * that we won't make the old 4*rto = almost no time - whoops
1651 * Nope, it was not mistake. It is really desired behaviour
1652 * f.e. on http servers, when such sockets are useless, but
1653 * consume significant resources. Let's do it with special
1654 * linger2 option. --ANK
1657 if (sk
->sk_state
== TCP_FIN_WAIT2
) {
1658 struct tcp_sock
*tp
= tcp_sk(sk
);
1659 if (tp
->linger2
< 0) {
1660 tcp_set_state(sk
, TCP_CLOSE
);
1661 tcp_send_active_reset(sk
, GFP_ATOMIC
);
1662 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER
);
1664 const int tmo
= tcp_fin_time(sk
);
1666 if (tmo
> TCP_TIMEWAIT_LEN
) {
1667 inet_csk_reset_keepalive_timer(sk
,
1668 tmo
- TCP_TIMEWAIT_LEN
);
1670 tcp_time_wait(sk
, TCP_FIN_WAIT2
, tmo
);
1675 if (sk
->sk_state
!= TCP_CLOSE
) {
1676 sk_stream_mem_reclaim(sk
);
1677 if (atomic_read(sk
->sk_prot
->orphan_count
) > sysctl_tcp_max_orphans
||
1678 (sk
->sk_wmem_queued
> SOCK_MIN_SNDBUF
&&
1679 atomic_read(&tcp_memory_allocated
) > sysctl_tcp_mem
[2])) {
1680 if (net_ratelimit())
1681 printk(KERN_INFO
"TCP: too many of orphaned "
1683 tcp_set_state(sk
, TCP_CLOSE
);
1684 tcp_send_active_reset(sk
, GFP_ATOMIC
);
1685 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY
);
1689 if (sk
->sk_state
== TCP_CLOSE
)
1690 inet_csk_destroy_sock(sk
);
1691 /* Otherwise, socket is reprieved until protocol close. */
1699 /* These states need RST on ABORT according to RFC793 */
1701 static inline int tcp_need_reset(int state
)
1703 return (1 << state
) &
1704 (TCPF_ESTABLISHED
| TCPF_CLOSE_WAIT
| TCPF_FIN_WAIT1
|
1705 TCPF_FIN_WAIT2
| TCPF_SYN_RECV
);
1708 int tcp_disconnect(struct sock
*sk
, int flags
)
1710 struct inet_sock
*inet
= inet_sk(sk
);
1711 struct inet_connection_sock
*icsk
= inet_csk(sk
);
1712 struct tcp_sock
*tp
= tcp_sk(sk
);
1714 int old_state
= sk
->sk_state
;
1716 if (old_state
!= TCP_CLOSE
)
1717 tcp_set_state(sk
, TCP_CLOSE
);
1719 /* ABORT function of RFC793 */
1720 if (old_state
== TCP_LISTEN
) {
1721 inet_csk_listen_stop(sk
);
1722 } else if (tcp_need_reset(old_state
) ||
1723 (tp
->snd_nxt
!= tp
->write_seq
&&
1724 (1 << old_state
) & (TCPF_CLOSING
| TCPF_LAST_ACK
))) {
1725 /* The last check adjusts for discrepancy of Linux wrt. RFC
1728 tcp_send_active_reset(sk
, gfp_any());
1729 sk
->sk_err
= ECONNRESET
;
1730 } else if (old_state
== TCP_SYN_SENT
)
1731 sk
->sk_err
= ECONNRESET
;
1733 tcp_clear_xmit_timers(sk
);
1734 __skb_queue_purge(&sk
->sk_receive_queue
);
1735 sk_stream_writequeue_purge(sk
);
1736 __skb_queue_purge(&tp
->out_of_order_queue
);
1737 #ifdef CONFIG_NET_DMA
1738 __skb_queue_purge(&sk
->sk_async_wait_queue
);
1743 if (!(sk
->sk_userlocks
& SOCK_BINDADDR_LOCK
))
1744 inet_reset_saddr(sk
);
1746 sk
->sk_shutdown
= 0;
1747 sock_reset_flag(sk
, SOCK_DONE
);
1749 if ((tp
->write_seq
+= tp
->max_window
+ 2) == 0)
1751 icsk
->icsk_backoff
= 0;
1753 icsk
->icsk_probes_out
= 0;
1754 tp
->packets_out
= 0;
1755 tp
->snd_ssthresh
= 0x7fffffff;
1756 tp
->snd_cwnd_cnt
= 0;
1757 tp
->bytes_acked
= 0;
1758 tcp_set_ca_state(sk
, TCP_CA_Open
);
1759 tcp_clear_retrans(tp
);
1760 inet_csk_delack_init(sk
);
1761 sk
->sk_send_head
= NULL
;
1762 tp
->rx_opt
.saw_tstamp
= 0;
1763 tcp_sack_reset(&tp
->rx_opt
);
1766 BUG_TRAP(!inet
->num
|| icsk
->icsk_bind_hash
);
1768 sk
->sk_error_report(sk
);
1773 * Socket option code for TCP.
1775 static int do_tcp_setsockopt(struct sock
*sk
, int level
,
1776 int optname
, char __user
*optval
, int optlen
)
1778 struct tcp_sock
*tp
= tcp_sk(sk
);
1779 struct inet_connection_sock
*icsk
= inet_csk(sk
);
1783 /* This is a string value all the others are int's */
1784 if (optname
== TCP_CONGESTION
) {
1785 char name
[TCP_CA_NAME_MAX
];
1790 val
= strncpy_from_user(name
, optval
,
1791 min(TCP_CA_NAME_MAX
-1, optlen
));
1797 err
= tcp_set_congestion_control(sk
, name
);
1802 if (optlen
< sizeof(int))
1805 if (get_user(val
, (int __user
*)optval
))
1812 /* Values greater than interface MTU won't take effect. However
1813 * at the point when this call is done we typically don't yet
1814 * know which interface is going to be used */
1815 if (val
< 8 || val
> MAX_TCP_WINDOW
) {
1819 tp
->rx_opt
.user_mss
= val
;
1824 /* TCP_NODELAY is weaker than TCP_CORK, so that
1825 * this option on corked socket is remembered, but
1826 * it is not activated until cork is cleared.
1828 * However, when TCP_NODELAY is set we make
1829 * an explicit push, which overrides even TCP_CORK
1830 * for currently queued segments.
1832 tp
->nonagle
|= TCP_NAGLE_OFF
|TCP_NAGLE_PUSH
;
1833 tcp_push_pending_frames(sk
, tp
);
1835 tp
->nonagle
&= ~TCP_NAGLE_OFF
;
1840 /* When set indicates to always queue non-full frames.
1841 * Later the user clears this option and we transmit
1842 * any pending partial frames in the queue. This is
1843 * meant to be used alongside sendfile() to get properly
1844 * filled frames when the user (for example) must write
1845 * out headers with a write() call first and then use
1846 * sendfile to send out the data parts.
1848 * TCP_CORK can be set together with TCP_NODELAY and it is
1849 * stronger than TCP_NODELAY.
1852 tp
->nonagle
|= TCP_NAGLE_CORK
;
1854 tp
->nonagle
&= ~TCP_NAGLE_CORK
;
1855 if (tp
->nonagle
&TCP_NAGLE_OFF
)
1856 tp
->nonagle
|= TCP_NAGLE_PUSH
;
1857 tcp_push_pending_frames(sk
, tp
);
1862 if (val
< 1 || val
> MAX_TCP_KEEPIDLE
)
1865 tp
->keepalive_time
= val
* HZ
;
1866 if (sock_flag(sk
, SOCK_KEEPOPEN
) &&
1867 !((1 << sk
->sk_state
) &
1868 (TCPF_CLOSE
| TCPF_LISTEN
))) {
1869 __u32 elapsed
= tcp_time_stamp
- tp
->rcv_tstamp
;
1870 if (tp
->keepalive_time
> elapsed
)
1871 elapsed
= tp
->keepalive_time
- elapsed
;
1874 inet_csk_reset_keepalive_timer(sk
, elapsed
);
1879 if (val
< 1 || val
> MAX_TCP_KEEPINTVL
)
1882 tp
->keepalive_intvl
= val
* HZ
;
1885 if (val
< 1 || val
> MAX_TCP_KEEPCNT
)
1888 tp
->keepalive_probes
= val
;
1891 if (val
< 1 || val
> MAX_TCP_SYNCNT
)
1894 icsk
->icsk_syn_retries
= val
;
1900 else if (val
> sysctl_tcp_fin_timeout
/ HZ
)
1903 tp
->linger2
= val
* HZ
;
1906 case TCP_DEFER_ACCEPT
:
1907 icsk
->icsk_accept_queue
.rskq_defer_accept
= 0;
1909 /* Translate value in seconds to number of
1911 while (icsk
->icsk_accept_queue
.rskq_defer_accept
< 32 &&
1912 val
> ((TCP_TIMEOUT_INIT
/ HZ
) <<
1913 icsk
->icsk_accept_queue
.rskq_defer_accept
))
1914 icsk
->icsk_accept_queue
.rskq_defer_accept
++;
1915 icsk
->icsk_accept_queue
.rskq_defer_accept
++;
1919 case TCP_WINDOW_CLAMP
:
1921 if (sk
->sk_state
!= TCP_CLOSE
) {
1925 tp
->window_clamp
= 0;
1927 tp
->window_clamp
= val
< SOCK_MIN_RCVBUF
/ 2 ?
1928 SOCK_MIN_RCVBUF
/ 2 : val
;
1933 icsk
->icsk_ack
.pingpong
= 1;
1935 icsk
->icsk_ack
.pingpong
= 0;
1936 if ((1 << sk
->sk_state
) &
1937 (TCPF_ESTABLISHED
| TCPF_CLOSE_WAIT
) &&
1938 inet_csk_ack_scheduled(sk
)) {
1939 icsk
->icsk_ack
.pending
|= ICSK_ACK_PUSHED
;
1940 tcp_cleanup_rbuf(sk
, 1);
1942 icsk
->icsk_ack
.pingpong
= 1;
1947 #ifdef CONFIG_TCP_MD5SIG
1949 /* Read the IP->Key mappings from userspace */
1950 err
= tp
->af_specific
->md5_parse(sk
, optval
, optlen
);
1962 int tcp_setsockopt(struct sock
*sk
, int level
, int optname
, char __user
*optval
,
1965 struct inet_connection_sock
*icsk
= inet_csk(sk
);
1967 if (level
!= SOL_TCP
)
1968 return icsk
->icsk_af_ops
->setsockopt(sk
, level
, optname
,
1970 return do_tcp_setsockopt(sk
, level
, optname
, optval
, optlen
);
1973 #ifdef CONFIG_COMPAT
1974 int compat_tcp_setsockopt(struct sock
*sk
, int level
, int optname
,
1975 char __user
*optval
, int optlen
)
1977 if (level
!= SOL_TCP
)
1978 return inet_csk_compat_setsockopt(sk
, level
, optname
,
1980 return do_tcp_setsockopt(sk
, level
, optname
, optval
, optlen
);
1983 EXPORT_SYMBOL(compat_tcp_setsockopt
);
1986 /* Return information about state of tcp endpoint in API format. */
1987 void tcp_get_info(struct sock
*sk
, struct tcp_info
*info
)
1989 struct tcp_sock
*tp
= tcp_sk(sk
);
1990 const struct inet_connection_sock
*icsk
= inet_csk(sk
);
1991 u32 now
= tcp_time_stamp
;
1993 memset(info
, 0, sizeof(*info
));
1995 info
->tcpi_state
= sk
->sk_state
;
1996 info
->tcpi_ca_state
= icsk
->icsk_ca_state
;
1997 info
->tcpi_retransmits
= icsk
->icsk_retransmits
;
1998 info
->tcpi_probes
= icsk
->icsk_probes_out
;
1999 info
->tcpi_backoff
= icsk
->icsk_backoff
;
2001 if (tp
->rx_opt
.tstamp_ok
)
2002 info
->tcpi_options
|= TCPI_OPT_TIMESTAMPS
;
2003 if (tp
->rx_opt
.sack_ok
)
2004 info
->tcpi_options
|= TCPI_OPT_SACK
;
2005 if (tp
->rx_opt
.wscale_ok
) {
2006 info
->tcpi_options
|= TCPI_OPT_WSCALE
;
2007 info
->tcpi_snd_wscale
= tp
->rx_opt
.snd_wscale
;
2008 info
->tcpi_rcv_wscale
= tp
->rx_opt
.rcv_wscale
;
2011 if (tp
->ecn_flags
&TCP_ECN_OK
)
2012 info
->tcpi_options
|= TCPI_OPT_ECN
;
2014 info
->tcpi_rto
= jiffies_to_usecs(icsk
->icsk_rto
);
2015 info
->tcpi_ato
= jiffies_to_usecs(icsk
->icsk_ack
.ato
);
2016 info
->tcpi_snd_mss
= tp
->mss_cache
;
2017 info
->tcpi_rcv_mss
= icsk
->icsk_ack
.rcv_mss
;
2019 info
->tcpi_unacked
= tp
->packets_out
;
2020 info
->tcpi_sacked
= tp
->sacked_out
;
2021 info
->tcpi_lost
= tp
->lost_out
;
2022 info
->tcpi_retrans
= tp
->retrans_out
;
2023 info
->tcpi_fackets
= tp
->fackets_out
;
2025 info
->tcpi_last_data_sent
= jiffies_to_msecs(now
- tp
->lsndtime
);
2026 info
->tcpi_last_data_recv
= jiffies_to_msecs(now
- icsk
->icsk_ack
.lrcvtime
);
2027 info
->tcpi_last_ack_recv
= jiffies_to_msecs(now
- tp
->rcv_tstamp
);
2029 info
->tcpi_pmtu
= icsk
->icsk_pmtu_cookie
;
2030 info
->tcpi_rcv_ssthresh
= tp
->rcv_ssthresh
;
2031 info
->tcpi_rtt
= jiffies_to_usecs(tp
->srtt
)>>3;
2032 info
->tcpi_rttvar
= jiffies_to_usecs(tp
->mdev
)>>2;
2033 info
->tcpi_snd_ssthresh
= tp
->snd_ssthresh
;
2034 info
->tcpi_snd_cwnd
= tp
->snd_cwnd
;
2035 info
->tcpi_advmss
= tp
->advmss
;
2036 info
->tcpi_reordering
= tp
->reordering
;
2038 info
->tcpi_rcv_rtt
= jiffies_to_usecs(tp
->rcv_rtt_est
.rtt
)>>3;
2039 info
->tcpi_rcv_space
= tp
->rcvq_space
.space
;
2041 info
->tcpi_total_retrans
= tp
->total_retrans
;
2044 EXPORT_SYMBOL_GPL(tcp_get_info
);
2046 static int do_tcp_getsockopt(struct sock
*sk
, int level
,
2047 int optname
, char __user
*optval
, int __user
*optlen
)
2049 struct inet_connection_sock
*icsk
= inet_csk(sk
);
2050 struct tcp_sock
*tp
= tcp_sk(sk
);
2053 if (get_user(len
, optlen
))
2056 len
= min_t(unsigned int, len
, sizeof(int));
2063 val
= tp
->mss_cache
;
2064 if (!val
&& ((1 << sk
->sk_state
) & (TCPF_CLOSE
| TCPF_LISTEN
)))
2065 val
= tp
->rx_opt
.user_mss
;
2068 val
= !!(tp
->nonagle
&TCP_NAGLE_OFF
);
2071 val
= !!(tp
->nonagle
&TCP_NAGLE_CORK
);
2074 val
= (tp
->keepalive_time
? : sysctl_tcp_keepalive_time
) / HZ
;
2077 val
= (tp
->keepalive_intvl
? : sysctl_tcp_keepalive_intvl
) / HZ
;
2080 val
= tp
->keepalive_probes
? : sysctl_tcp_keepalive_probes
;
2083 val
= icsk
->icsk_syn_retries
? : sysctl_tcp_syn_retries
;
2088 val
= (val
? : sysctl_tcp_fin_timeout
) / HZ
;
2090 case TCP_DEFER_ACCEPT
:
2091 val
= !icsk
->icsk_accept_queue
.rskq_defer_accept
? 0 :
2092 ((TCP_TIMEOUT_INIT
/ HZ
) << (icsk
->icsk_accept_queue
.rskq_defer_accept
- 1));
2094 case TCP_WINDOW_CLAMP
:
2095 val
= tp
->window_clamp
;
2098 struct tcp_info info
;
2100 if (get_user(len
, optlen
))
2103 tcp_get_info(sk
, &info
);
2105 len
= min_t(unsigned int, len
, sizeof(info
));
2106 if (put_user(len
, optlen
))
2108 if (copy_to_user(optval
, &info
, len
))
2113 val
= !icsk
->icsk_ack
.pingpong
;
2116 case TCP_CONGESTION
:
2117 if (get_user(len
, optlen
))
2119 len
= min_t(unsigned int, len
, TCP_CA_NAME_MAX
);
2120 if (put_user(len
, optlen
))
2122 if (copy_to_user(optval
, icsk
->icsk_ca_ops
->name
, len
))
2126 return -ENOPROTOOPT
;
2129 if (put_user(len
, optlen
))
2131 if (copy_to_user(optval
, &val
, len
))
2136 int tcp_getsockopt(struct sock
*sk
, int level
, int optname
, char __user
*optval
,
2139 struct inet_connection_sock
*icsk
= inet_csk(sk
);
2141 if (level
!= SOL_TCP
)
2142 return icsk
->icsk_af_ops
->getsockopt(sk
, level
, optname
,
2144 return do_tcp_getsockopt(sk
, level
, optname
, optval
, optlen
);
2147 #ifdef CONFIG_COMPAT
2148 int compat_tcp_getsockopt(struct sock
*sk
, int level
, int optname
,
2149 char __user
*optval
, int __user
*optlen
)
2151 if (level
!= SOL_TCP
)
2152 return inet_csk_compat_getsockopt(sk
, level
, optname
,
2154 return do_tcp_getsockopt(sk
, level
, optname
, optval
, optlen
);
2157 EXPORT_SYMBOL(compat_tcp_getsockopt
);
2160 struct sk_buff
*tcp_tso_segment(struct sk_buff
*skb
, int features
)
2162 struct sk_buff
*segs
= ERR_PTR(-EINVAL
);
2167 unsigned int oldlen
;
2170 if (!pskb_may_pull(skb
, sizeof(*th
)))
2174 thlen
= th
->doff
* 4;
2175 if (thlen
< sizeof(*th
))
2178 if (!pskb_may_pull(skb
, thlen
))
2181 oldlen
= (u16
)~skb
->len
;
2182 __skb_pull(skb
, thlen
);
2184 if (skb_gso_ok(skb
, features
| NETIF_F_GSO_ROBUST
)) {
2185 /* Packet is from an untrusted source, reset gso_segs. */
2186 int type
= skb_shinfo(skb
)->gso_type
;
2195 !(type
& (SKB_GSO_TCPV4
| SKB_GSO_TCPV6
))))
2198 mss
= skb_shinfo(skb
)->gso_size
;
2199 skb_shinfo(skb
)->gso_segs
= (skb
->len
+ mss
- 1) / mss
;
2205 segs
= skb_segment(skb
, features
);
2209 len
= skb_shinfo(skb
)->gso_size
;
2210 delta
= htonl(oldlen
+ (thlen
+ len
));
2214 seq
= ntohl(th
->seq
);
2217 th
->fin
= th
->psh
= 0;
2219 th
->check
= ~csum_fold((__force __wsum
)((__force u32
)th
->check
+
2220 (__force u32
)delta
));
2221 if (skb
->ip_summed
!= CHECKSUM_PARTIAL
)
2222 th
->check
= csum_fold(csum_partial(skb
->h
.raw
, thlen
,
2229 th
->seq
= htonl(seq
);
2231 } while (skb
->next
);
2233 delta
= htonl(oldlen
+ (skb
->tail
- skb
->h
.raw
) + skb
->data_len
);
2234 th
->check
= ~csum_fold((__force __wsum
)((__force u32
)th
->check
+
2235 (__force u32
)delta
));
2236 if (skb
->ip_summed
!= CHECKSUM_PARTIAL
)
2237 th
->check
= csum_fold(csum_partial(skb
->h
.raw
, thlen
,
2243 EXPORT_SYMBOL(tcp_tso_segment
);
2245 #ifdef CONFIG_TCP_MD5SIG
2246 static unsigned long tcp_md5sig_users
;
2247 static struct tcp_md5sig_pool
**tcp_md5sig_pool
;
2248 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock
);
2250 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool
**pool
)
2253 for_each_possible_cpu(cpu
) {
2254 struct tcp_md5sig_pool
*p
= *per_cpu_ptr(pool
, cpu
);
2256 if (p
->md5_desc
.tfm
)
2257 crypto_free_hash(p
->md5_desc
.tfm
);
2265 void tcp_free_md5sig_pool(void)
2267 struct tcp_md5sig_pool
**pool
= NULL
;
2269 spin_lock_bh(&tcp_md5sig_pool_lock
);
2270 if (--tcp_md5sig_users
== 0) {
2271 pool
= tcp_md5sig_pool
;
2272 tcp_md5sig_pool
= NULL
;
2274 spin_unlock_bh(&tcp_md5sig_pool_lock
);
2276 __tcp_free_md5sig_pool(pool
);
2279 EXPORT_SYMBOL(tcp_free_md5sig_pool
);
2281 static struct tcp_md5sig_pool
**__tcp_alloc_md5sig_pool(void)
2284 struct tcp_md5sig_pool
**pool
;
2286 pool
= alloc_percpu(struct tcp_md5sig_pool
*);
2290 for_each_possible_cpu(cpu
) {
2291 struct tcp_md5sig_pool
*p
;
2292 struct crypto_hash
*hash
;
2294 p
= kzalloc(sizeof(*p
), GFP_KERNEL
);
2297 *per_cpu_ptr(pool
, cpu
) = p
;
2299 hash
= crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC
);
2300 if (!hash
|| IS_ERR(hash
))
2303 p
->md5_desc
.tfm
= hash
;
2307 __tcp_free_md5sig_pool(pool
);
2311 struct tcp_md5sig_pool
**tcp_alloc_md5sig_pool(void)
2313 struct tcp_md5sig_pool
**pool
;
2317 spin_lock_bh(&tcp_md5sig_pool_lock
);
2318 pool
= tcp_md5sig_pool
;
2319 if (tcp_md5sig_users
++ == 0) {
2321 spin_unlock_bh(&tcp_md5sig_pool_lock
);
2324 spin_unlock_bh(&tcp_md5sig_pool_lock
);
2328 spin_unlock_bh(&tcp_md5sig_pool_lock
);
2331 /* we cannot hold spinlock here because this may sleep. */
2332 struct tcp_md5sig_pool
**p
= __tcp_alloc_md5sig_pool();
2333 spin_lock_bh(&tcp_md5sig_pool_lock
);
2336 spin_unlock_bh(&tcp_md5sig_pool_lock
);
2339 pool
= tcp_md5sig_pool
;
2341 /* oops, it has already been assigned. */
2342 spin_unlock_bh(&tcp_md5sig_pool_lock
);
2343 __tcp_free_md5sig_pool(p
);
2345 tcp_md5sig_pool
= pool
= p
;
2346 spin_unlock_bh(&tcp_md5sig_pool_lock
);
2352 EXPORT_SYMBOL(tcp_alloc_md5sig_pool
);
2354 struct tcp_md5sig_pool
*__tcp_get_md5sig_pool(int cpu
)
2356 struct tcp_md5sig_pool
**p
;
2357 spin_lock_bh(&tcp_md5sig_pool_lock
);
2358 p
= tcp_md5sig_pool
;
2361 spin_unlock_bh(&tcp_md5sig_pool_lock
);
2362 return (p
? *per_cpu_ptr(p
, cpu
) : NULL
);
2365 EXPORT_SYMBOL(__tcp_get_md5sig_pool
);
2367 void __tcp_put_md5sig_pool(void)
2369 tcp_free_md5sig_pool();
2372 EXPORT_SYMBOL(__tcp_put_md5sig_pool
);
2375 extern void __skb_cb_too_small_for_tcp(int, int);
2376 extern struct tcp_congestion_ops tcp_reno
;
2378 static __initdata
unsigned long thash_entries
;
2379 static int __init
set_thash_entries(char *str
)
2383 thash_entries
= simple_strtoul(str
, &str
, 0);
2386 __setup("thash_entries=", set_thash_entries
);
2388 void __init
tcp_init(void)
2390 struct sk_buff
*skb
= NULL
;
2391 unsigned long limit
;
2392 int order
, i
, max_share
;
2394 if (sizeof(struct tcp_skb_cb
) > sizeof(skb
->cb
))
2395 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb
),
2398 tcp_hashinfo
.bind_bucket_cachep
=
2399 kmem_cache_create("tcp_bind_bucket",
2400 sizeof(struct inet_bind_bucket
), 0,
2401 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
, NULL
);
2403 /* Size and allocate the main established and bind bucket
2406 * The methodology is similar to that of the buffer cache.
2408 tcp_hashinfo
.ehash
=
2409 alloc_large_system_hash("TCP established",
2410 sizeof(struct inet_ehash_bucket
),
2412 (num_physpages
>= 128 * 1024) ?
2415 &tcp_hashinfo
.ehash_size
,
2418 tcp_hashinfo
.ehash_size
= (1 << tcp_hashinfo
.ehash_size
) >> 1;
2419 for (i
= 0; i
< (tcp_hashinfo
.ehash_size
<< 1); i
++) {
2420 rwlock_init(&tcp_hashinfo
.ehash
[i
].lock
);
2421 INIT_HLIST_HEAD(&tcp_hashinfo
.ehash
[i
].chain
);
2424 tcp_hashinfo
.bhash
=
2425 alloc_large_system_hash("TCP bind",
2426 sizeof(struct inet_bind_hashbucket
),
2427 tcp_hashinfo
.ehash_size
,
2428 (num_physpages
>= 128 * 1024) ?
2431 &tcp_hashinfo
.bhash_size
,
2434 tcp_hashinfo
.bhash_size
= 1 << tcp_hashinfo
.bhash_size
;
2435 for (i
= 0; i
< tcp_hashinfo
.bhash_size
; i
++) {
2436 spin_lock_init(&tcp_hashinfo
.bhash
[i
].lock
);
2437 INIT_HLIST_HEAD(&tcp_hashinfo
.bhash
[i
].chain
);
2440 /* Try to be a bit smarter and adjust defaults depending
2441 * on available memory.
2443 for (order
= 0; ((1 << order
) << PAGE_SHIFT
) <
2444 (tcp_hashinfo
.bhash_size
* sizeof(struct inet_bind_hashbucket
));
2448 tcp_death_row
.sysctl_max_tw_buckets
= 180000;
2449 sysctl_tcp_max_orphans
= 4096 << (order
- 4);
2450 sysctl_max_syn_backlog
= 1024;
2451 } else if (order
< 3) {
2452 tcp_death_row
.sysctl_max_tw_buckets
>>= (3 - order
);
2453 sysctl_tcp_max_orphans
>>= (3 - order
);
2454 sysctl_max_syn_backlog
= 128;
2457 /* Set the pressure threshold to be a fraction of global memory that
2458 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2459 * memory, with a floor of 128 pages.
2461 limit
= min(nr_all_pages
, 1UL<<(28-PAGE_SHIFT
)) >> (20-PAGE_SHIFT
);
2462 limit
= (limit
* (nr_all_pages
>> (20-PAGE_SHIFT
))) >> (PAGE_SHIFT
-11);
2463 limit
= max(limit
, 128UL);
2464 sysctl_tcp_mem
[0] = limit
/ 4 * 3;
2465 sysctl_tcp_mem
[1] = limit
;
2466 sysctl_tcp_mem
[2] = sysctl_tcp_mem
[0] * 2;
2468 /* Set per-socket limits to no more than 1/128 the pressure threshold */
2469 limit
= ((unsigned long)sysctl_tcp_mem
[1]) << (PAGE_SHIFT
- 7);
2470 max_share
= min(4UL*1024*1024, limit
);
2472 sysctl_tcp_wmem
[0] = SK_STREAM_MEM_QUANTUM
;
2473 sysctl_tcp_wmem
[1] = 16*1024;
2474 sysctl_tcp_wmem
[2] = max(64*1024, max_share
);
2476 sysctl_tcp_rmem
[0] = SK_STREAM_MEM_QUANTUM
;
2477 sysctl_tcp_rmem
[1] = 87380;
2478 sysctl_tcp_rmem
[2] = max(87380, max_share
);
2480 printk(KERN_INFO
"TCP: Hash tables configured "
2481 "(established %d bind %d)\n",
2482 tcp_hashinfo
.ehash_size
<< 1, tcp_hashinfo
.bhash_size
);
2484 tcp_register_congestion_control(&tcp_reno
);
2487 EXPORT_SYMBOL(tcp_close
);
2488 EXPORT_SYMBOL(tcp_disconnect
);
2489 EXPORT_SYMBOL(tcp_getsockopt
);
2490 EXPORT_SYMBOL(tcp_ioctl
);
2491 EXPORT_SYMBOL(tcp_poll
);
2492 EXPORT_SYMBOL(tcp_read_sock
);
2493 EXPORT_SYMBOL(tcp_recvmsg
);
2494 EXPORT_SYMBOL(tcp_sendmsg
);
2495 EXPORT_SYMBOL(tcp_sendpage
);
2496 EXPORT_SYMBOL(tcp_setsockopt
);
2497 EXPORT_SYMBOL(tcp_shutdown
);
2498 EXPORT_SYMBOL(tcp_statistics
);