tcp.c revision 57ef42d59d1c1d79be59fc3c6380ae14234e38c3
1/* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * Implementation of the Transmission Control Protocol(TCP). 7 * 8 * Authors: Ross Biro 9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 10 * Mark Evans, <evansmp@uhura.aston.ac.uk> 11 * Corey Minyard <wf-rch!minyard@relay.EU.net> 12 * Florian La Roche, <flla@stud.uni-sb.de> 13 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu> 14 * Linus Torvalds, <torvalds@cs.helsinki.fi> 15 * Alan Cox, <gw4pts@gw4pts.ampr.org> 16 * Matthew Dillon, <dillon@apollo.west.oic.com> 17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 18 * Jorge Cwik, <jorge@laser.satlink.net> 19 * 20 * Fixes: 21 * Alan Cox : Numerous verify_area() calls 22 * Alan Cox : Set the ACK bit on a reset 23 * Alan Cox : Stopped it crashing if it closed while 24 * sk->inuse=1 and was trying to connect 25 * (tcp_err()). 26 * Alan Cox : All icmp error handling was broken 27 * pointers passed where wrong and the 28 * socket was looked up backwards. Nobody 29 * tested any icmp error code obviously. 30 * Alan Cox : tcp_err() now handled properly. It 31 * wakes people on errors. poll 32 * behaves and the icmp error race 33 * has gone by moving it into sock.c 34 * Alan Cox : tcp_send_reset() fixed to work for 35 * everything not just packets for 36 * unknown sockets. 37 * Alan Cox : tcp option processing. 38 * Alan Cox : Reset tweaked (still not 100%) [Had 39 * syn rule wrong] 40 * Herp Rosmanith : More reset fixes 41 * Alan Cox : No longer acks invalid rst frames. 42 * Acking any kind of RST is right out. 43 * Alan Cox : Sets an ignore me flag on an rst 44 * receive otherwise odd bits of prattle 45 * escape still 46 * Alan Cox : Fixed another acking RST frame bug. 47 * Should stop LAN workplace lockups. 48 * Alan Cox : Some tidyups using the new skb list 49 * facilities 50 * Alan Cox : sk->keepopen now seems to work 51 * Alan Cox : Pulls options out correctly on accepts 52 * Alan Cox : Fixed assorted sk->rqueue->next errors 53 * Alan Cox : PSH doesn't end a TCP read. Switched a 54 * bit to skb ops. 55 * Alan Cox : Tidied tcp_data to avoid a potential 56 * nasty. 57 * Alan Cox : Added some better commenting, as the 58 * tcp is hard to follow 59 * Alan Cox : Removed incorrect check for 20 * psh 60 * Michael O'Reilly : ack < copied bug fix. 61 * Johannes Stille : Misc tcp fixes (not all in yet). 62 * Alan Cox : FIN with no memory -> CRASH 63 * Alan Cox : Added socket option proto entries. 64 * Also added awareness of them to accept. 65 * Alan Cox : Added TCP options (SOL_TCP) 66 * Alan Cox : Switched wakeup calls to callbacks, 67 * so the kernel can layer network 68 * sockets. 69 * Alan Cox : Use ip_tos/ip_ttl settings. 70 * Alan Cox : Handle FIN (more) properly (we hope). 71 * Alan Cox : RST frames sent on unsynchronised 72 * state ack error. 73 * Alan Cox : Put in missing check for SYN bit. 74 * Alan Cox : Added tcp_select_window() aka NET2E 75 * window non shrink trick. 76 * Alan Cox : Added a couple of small NET2E timer 77 * fixes 78 * Charles Hedrick : TCP fixes 79 * Toomas Tamm : TCP window fixes 80 * Alan Cox : Small URG fix to rlogin ^C ack fight 81 * Charles Hedrick : Rewrote most of it to actually work 82 * Linus : Rewrote tcp_read() and URG handling 83 * completely 84 * Gerhard Koerting: Fixed some missing timer handling 85 * Matthew Dillon : Reworked TCP machine states as per RFC 86 * Gerhard Koerting: PC/TCP workarounds 87 * Adam Caldwell : Assorted timer/timing errors 88 * Matthew Dillon : Fixed another RST bug 89 * Alan Cox : Move to kernel side addressing changes. 90 * Alan Cox : Beginning work on TCP fastpathing 91 * (not yet usable) 92 * Arnt Gulbrandsen: Turbocharged tcp_check() routine. 93 * Alan Cox : TCP fast path debugging 94 * Alan Cox : Window clamping 95 * Michael Riepe : Bug in tcp_check() 96 * Matt Dillon : More TCP improvements and RST bug fixes 97 * Matt Dillon : Yet more small nasties remove from the 98 * TCP code (Be very nice to this man if 99 * tcp finally works 100%) 8) 100 * Alan Cox : BSD accept semantics. 101 * Alan Cox : Reset on closedown bug. 102 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto(). 103 * Michael Pall : Handle poll() after URG properly in 104 * all cases. 105 * Michael Pall : Undo the last fix in tcp_read_urg() 106 * (multi URG PUSH broke rlogin). 107 * Michael Pall : Fix the multi URG PUSH problem in 108 * tcp_readable(), poll() after URG 109 * works now. 110 * Michael Pall : recv(...,MSG_OOB) never blocks in the 111 * BSD api. 112 * Alan Cox : Changed the semantics of sk->socket to 113 * fix a race and a signal problem with 114 * accept() and async I/O. 115 * Alan Cox : Relaxed the rules on tcp_sendto(). 116 * Yury Shevchuk : Really fixed accept() blocking problem. 117 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for 118 * clients/servers which listen in on 119 * fixed ports. 120 * Alan Cox : Cleaned the above up and shrank it to 121 * a sensible code size. 122 * Alan Cox : Self connect lockup fix. 123 * Alan Cox : No connect to multicast. 124 * Ross Biro : Close unaccepted children on master 125 * socket close. 126 * Alan Cox : Reset tracing code. 127 * Alan Cox : Spurious resets on shutdown. 128 * Alan Cox : Giant 15 minute/60 second timer error 129 * Alan Cox : Small whoops in polling before an 130 * accept. 131 * Alan Cox : Kept the state trace facility since 132 * it's handy for debugging. 133 * Alan Cox : More reset handler fixes. 134 * Alan Cox : Started rewriting the code based on 135 * the RFC's for other useful protocol 136 * references see: Comer, KA9Q NOS, and 137 * for a reference on the difference 138 * between specifications and how BSD 139 * works see the 4.4lite source. 140 * A.N.Kuznetsov : Don't time wait on completion of tidy 141 * close. 142 * Linus Torvalds : Fin/Shutdown & copied_seq changes. 143 * Linus Torvalds : Fixed BSD port reuse to work first syn 144 * Alan Cox : Reimplemented timers as per the RFC 145 * and using multiple timers for sanity. 146 * Alan Cox : Small bug fixes, and a lot of new 147 * comments. 148 * Alan Cox : Fixed dual reader crash by locking 149 * the buffers (much like datagram.c) 150 * Alan Cox : Fixed stuck sockets in probe. A probe 151 * now gets fed up of retrying without 152 * (even a no space) answer. 153 * Alan Cox : Extracted closing code better 154 * Alan Cox : Fixed the closing state machine to 155 * resemble the RFC. 156 * Alan Cox : More 'per spec' fixes. 157 * Jorge Cwik : Even faster checksumming. 158 * Alan Cox : tcp_data() doesn't ack illegal PSH 159 * only frames. At least one pc tcp stack 160 * generates them. 161 * Alan Cox : Cache last socket. 162 * Alan Cox : Per route irtt. 163 * Matt Day : poll()->select() match BSD precisely on error 164 * Alan Cox : New buffers 165 * Marc Tamsky : Various sk->prot->retransmits and 166 * sk->retransmits misupdating fixed. 167 * Fixed tcp_write_timeout: stuck close, 168 * and TCP syn retries gets used now. 169 * Mark Yarvis : In tcp_read_wakeup(), don't send an 170 * ack if state is TCP_CLOSED. 171 * Alan Cox : Look up device on a retransmit - routes may 172 * change. Doesn't yet cope with MSS shrink right 173 * but it's a start! 174 * Marc Tamsky : Closing in closing fixes. 175 * Mike Shaver : RFC1122 verifications. 176 * Alan Cox : rcv_saddr errors. 177 * Alan Cox : Block double connect(). 178 * Alan Cox : Small hooks for enSKIP. 179 * Alexey Kuznetsov: Path MTU discovery. 180 * Alan Cox : Support soft errors. 181 * Alan Cox : Fix MTU discovery pathological case 182 * when the remote claims no mtu! 183 * Marc Tamsky : TCP_CLOSE fix. 184 * Colin (G3TNE) : Send a reset on syn ack replies in 185 * window but wrong (fixes NT lpd problems) 186 * Pedro Roque : Better TCP window handling, delayed ack. 187 * Joerg Reuter : No modification of locked buffers in 188 * tcp_do_retransmit() 189 * Eric Schenk : Changed receiver side silly window 190 * avoidance algorithm to BSD style 191 * algorithm. This doubles throughput 192 * against machines running Solaris, 193 * and seems to result in general 194 * improvement. 195 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD 196 * Willy Konynenberg : Transparent proxying support. 197 * Mike McLagan : Routing by source 198 * Keith Owens : Do proper merging with partial SKB's in 199 * tcp_do_sendmsg to avoid burstiness. 200 * Eric Schenk : Fix fast close down bug with 201 * shutdown() followed by close(). 202 * Andi Kleen : Make poll agree with SIGIO 203 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and 204 * lingertime == 0 (RFC 793 ABORT Call) 205 * Hirokazu Takahashi : Use copy_from_user() instead of 206 * csum_and_copy_from_user() if possible. 207 * 208 * This program is free software; you can redistribute it and/or 209 * modify it under the terms of the GNU General Public License 210 * as published by the Free Software Foundation; either version 211 * 2 of the License, or(at your option) any later version. 212 * 213 * Description of States: 214 * 215 * TCP_SYN_SENT sent a connection request, waiting for ack 216 * 217 * TCP_SYN_RECV received a connection request, sent ack, 218 * waiting for final ack in three-way handshake. 219 * 220 * TCP_ESTABLISHED connection established 221 * 222 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete 223 * transmission of remaining buffered data 224 * 225 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote 226 * to shutdown 227 * 228 * TCP_CLOSING both sides have shutdown but we still have 229 * data we have to finish sending 230 * 231 * TCP_TIME_WAIT timeout to catch resent junk before entering 232 * closed, can only be entered from FIN_WAIT2 233 * or CLOSING. Required because the other end 234 * may not have gotten our last ACK causing it 235 * to retransmit the data packet (which we ignore) 236 * 237 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for 238 * us to finish writing our data and to shutdown 239 * (we have to close() to move on to LAST_ACK) 240 * 241 * TCP_LAST_ACK out side has shutdown after remote has 242 * shutdown. There may still be data in our 243 * buffer that we have to finish sending 244 * 245 * TCP_CLOSE socket is finished 246 */ 247 248#include <linux/kernel.h> 249#include <linux/module.h> 250#include <linux/types.h> 251#include <linux/fcntl.h> 252#include <linux/poll.h> 253#include <linux/init.h> 254#include <linux/fs.h> 255#include <linux/skbuff.h> 256#include <linux/scatterlist.h> 257#include <linux/splice.h> 258#include <linux/net.h> 259#include <linux/socket.h> 260#include <linux/random.h> 261#include <linux/bootmem.h> 262#include <linux/highmem.h> 263#include <linux/swap.h> 264#include <linux/cache.h> 265#include <linux/err.h> 266#include <linux/crypto.h> 267 268#include <net/icmp.h> 269#include <net/tcp.h> 270#include <net/xfrm.h> 271#include <net/ip.h> 272#include <net/netdma.h> 273#include <net/sock.h> 274 275#include <asm/uaccess.h> 276#include <asm/ioctls.h> 277 278int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 279 280atomic_t tcp_orphan_count = ATOMIC_INIT(0); 281 282EXPORT_SYMBOL_GPL(tcp_orphan_count); 283 284int sysctl_tcp_mem[3] __read_mostly; 285int sysctl_tcp_wmem[3] __read_mostly; 286int sysctl_tcp_rmem[3] __read_mostly; 287 288EXPORT_SYMBOL(sysctl_tcp_mem); 289EXPORT_SYMBOL(sysctl_tcp_rmem); 290EXPORT_SYMBOL(sysctl_tcp_wmem); 291 292atomic_t tcp_memory_allocated; /* Current allocated memory. */ 293atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */ 294 295EXPORT_SYMBOL(tcp_memory_allocated); 296EXPORT_SYMBOL(tcp_sockets_allocated); 297 298/* 299 * TCP splice context 300 */ 301struct tcp_splice_state { 302 struct pipe_inode_info *pipe; 303 size_t len; 304 unsigned int flags; 305}; 306 307/* 308 * Pressure flag: try to collapse. 309 * Technical note: it is used by multiple contexts non atomically. 310 * All the __sk_mem_schedule() is of this nature: accounting 311 * is strict, actions are advisory and have some latency. 312 */ 313int tcp_memory_pressure __read_mostly; 314 315EXPORT_SYMBOL(tcp_memory_pressure); 316 317void tcp_enter_memory_pressure(struct sock *sk) 318{ 319 if (!tcp_memory_pressure) { 320 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES); 321 tcp_memory_pressure = 1; 322 } 323} 324 325EXPORT_SYMBOL(tcp_enter_memory_pressure); 326 327/* 328 * Wait for a TCP event. 329 * 330 * Note that we don't need to lock the socket, as the upper poll layers 331 * take care of normal races (between the test and the event) and we don't 332 * go look at any of the socket buffers directly. 333 */ 334unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 335{ 336 unsigned int mask; 337 struct sock *sk = sock->sk; 338 struct tcp_sock *tp = tcp_sk(sk); 339 340 poll_wait(file, sk->sk_sleep, wait); 341 if (sk->sk_state == TCP_LISTEN) 342 return inet_csk_listen_poll(sk); 343 344 /* Socket is not locked. We are protected from async events 345 * by poll logic and correct handling of state changes 346 * made by other threads is impossible in any case. 347 */ 348 349 mask = 0; 350 if (sk->sk_err) 351 mask = POLLERR; 352 353 /* 354 * POLLHUP is certainly not done right. But poll() doesn't 355 * have a notion of HUP in just one direction, and for a 356 * socket the read side is more interesting. 357 * 358 * Some poll() documentation says that POLLHUP is incompatible 359 * with the POLLOUT/POLLWR flags, so somebody should check this 360 * all. But careful, it tends to be safer to return too many 361 * bits than too few, and you can easily break real applications 362 * if you don't tell them that something has hung up! 363 * 364 * Check-me. 365 * 366 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 367 * our fs/select.c). It means that after we received EOF, 368 * poll always returns immediately, making impossible poll() on write() 369 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 370 * if and only if shutdown has been made in both directions. 371 * Actually, it is interesting to look how Solaris and DUX 372 * solve this dilemma. I would prefer, if POLLHUP were maskable, 373 * then we could set it on SND_SHUTDOWN. BTW examples given 374 * in Stevens' books assume exactly this behaviour, it explains 375 * why POLLHUP is incompatible with POLLOUT. --ANK 376 * 377 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 378 * blocking on fresh not-connected or disconnected socket. --ANK 379 */ 380 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 381 mask |= POLLHUP; 382 if (sk->sk_shutdown & RCV_SHUTDOWN) 383 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 384 385 /* Connected? */ 386 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) { 387 /* Potential race condition. If read of tp below will 388 * escape above sk->sk_state, we can be illegally awaken 389 * in SYN_* states. */ 390 if ((tp->rcv_nxt != tp->copied_seq) && 391 (tp->urg_seq != tp->copied_seq || 392 tp->rcv_nxt != tp->copied_seq + 1 || 393 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data)) 394 mask |= POLLIN | POLLRDNORM; 395 396 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 397 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) { 398 mask |= POLLOUT | POLLWRNORM; 399 } else { /* send SIGIO later */ 400 set_bit(SOCK_ASYNC_NOSPACE, 401 &sk->sk_socket->flags); 402 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 403 404 /* Race breaker. If space is freed after 405 * wspace test but before the flags are set, 406 * IO signal will be lost. 407 */ 408 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) 409 mask |= POLLOUT | POLLWRNORM; 410 } 411 } 412 413 if (tp->urg_data & TCP_URG_VALID) 414 mask |= POLLPRI; 415 } 416 return mask; 417} 418 419int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 420{ 421 struct tcp_sock *tp = tcp_sk(sk); 422 int answ; 423 424 switch (cmd) { 425 case SIOCINQ: 426 if (sk->sk_state == TCP_LISTEN) 427 return -EINVAL; 428 429 lock_sock(sk); 430 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 431 answ = 0; 432 else if (sock_flag(sk, SOCK_URGINLINE) || 433 !tp->urg_data || 434 before(tp->urg_seq, tp->copied_seq) || 435 !before(tp->urg_seq, tp->rcv_nxt)) { 436 answ = tp->rcv_nxt - tp->copied_seq; 437 438 /* Subtract 1, if FIN is in queue. */ 439 if (answ && !skb_queue_empty(&sk->sk_receive_queue)) 440 answ -= 441 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin; 442 } else 443 answ = tp->urg_seq - tp->copied_seq; 444 release_sock(sk); 445 break; 446 case SIOCATMARK: 447 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 448 break; 449 case SIOCOUTQ: 450 if (sk->sk_state == TCP_LISTEN) 451 return -EINVAL; 452 453 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 454 answ = 0; 455 else 456 answ = tp->write_seq - tp->snd_una; 457 break; 458 default: 459 return -ENOIOCTLCMD; 460 } 461 462 return put_user(answ, (int __user *)arg); 463} 464 465static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 466{ 467 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH; 468 tp->pushed_seq = tp->write_seq; 469} 470 471static inline int forced_push(struct tcp_sock *tp) 472{ 473 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 474} 475 476static inline void skb_entail(struct sock *sk, struct sk_buff *skb) 477{ 478 struct tcp_sock *tp = tcp_sk(sk); 479 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 480 481 skb->csum = 0; 482 tcb->seq = tcb->end_seq = tp->write_seq; 483 tcb->flags = TCPCB_FLAG_ACK; 484 tcb->sacked = 0; 485 skb_header_release(skb); 486 tcp_add_write_queue_tail(sk, skb); 487 sk->sk_wmem_queued += skb->truesize; 488 sk_mem_charge(sk, skb->truesize); 489 if (tp->nonagle & TCP_NAGLE_PUSH) 490 tp->nonagle &= ~TCP_NAGLE_PUSH; 491} 492 493static inline void tcp_mark_urg(struct tcp_sock *tp, int flags, 494 struct sk_buff *skb) 495{ 496 if (flags & MSG_OOB) { 497 tp->urg_mode = 1; 498 tp->snd_up = tp->write_seq; 499 } 500} 501 502static inline void tcp_push(struct sock *sk, int flags, int mss_now, 503 int nonagle) 504{ 505 struct tcp_sock *tp = tcp_sk(sk); 506 507 if (tcp_send_head(sk)) { 508 struct sk_buff *skb = tcp_write_queue_tail(sk); 509 if (!(flags & MSG_MORE) || forced_push(tp)) 510 tcp_mark_push(tp, skb); 511 tcp_mark_urg(tp, flags, skb); 512 __tcp_push_pending_frames(sk, mss_now, 513 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle); 514 } 515} 516 517static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, 518 unsigned int offset, size_t len) 519{ 520 struct tcp_splice_state *tss = rd_desc->arg.data; 521 522 return skb_splice_bits(skb, offset, tss->pipe, tss->len, tss->flags); 523} 524 525static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss) 526{ 527 /* Store TCP splice context information in read_descriptor_t. */ 528 read_descriptor_t rd_desc = { 529 .arg.data = tss, 530 }; 531 532 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv); 533} 534 535/** 536 * tcp_splice_read - splice data from TCP socket to a pipe 537 * @sock: socket to splice from 538 * @ppos: position (not valid) 539 * @pipe: pipe to splice to 540 * @len: number of bytes to splice 541 * @flags: splice modifier flags 542 * 543 * Description: 544 * Will read pages from given socket and fill them into a pipe. 545 * 546 **/ 547ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, 548 struct pipe_inode_info *pipe, size_t len, 549 unsigned int flags) 550{ 551 struct sock *sk = sock->sk; 552 struct tcp_splice_state tss = { 553 .pipe = pipe, 554 .len = len, 555 .flags = flags, 556 }; 557 long timeo; 558 ssize_t spliced; 559 int ret; 560 561 /* 562 * We can't seek on a socket input 563 */ 564 if (unlikely(*ppos)) 565 return -ESPIPE; 566 567 ret = spliced = 0; 568 569 lock_sock(sk); 570 571 timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK); 572 while (tss.len) { 573 ret = __tcp_splice_read(sk, &tss); 574 if (ret < 0) 575 break; 576 else if (!ret) { 577 if (spliced) 578 break; 579 if (flags & SPLICE_F_NONBLOCK) { 580 ret = -EAGAIN; 581 break; 582 } 583 if (sock_flag(sk, SOCK_DONE)) 584 break; 585 if (sk->sk_err) { 586 ret = sock_error(sk); 587 break; 588 } 589 if (sk->sk_shutdown & RCV_SHUTDOWN) 590 break; 591 if (sk->sk_state == TCP_CLOSE) { 592 /* 593 * This occurs when user tries to read 594 * from never connected socket. 595 */ 596 if (!sock_flag(sk, SOCK_DONE)) 597 ret = -ENOTCONN; 598 break; 599 } 600 if (!timeo) { 601 ret = -EAGAIN; 602 break; 603 } 604 sk_wait_data(sk, &timeo); 605 if (signal_pending(current)) { 606 ret = sock_intr_errno(timeo); 607 break; 608 } 609 continue; 610 } 611 tss.len -= ret; 612 spliced += ret; 613 614 release_sock(sk); 615 lock_sock(sk); 616 617 if (sk->sk_err || sk->sk_state == TCP_CLOSE || 618 (sk->sk_shutdown & RCV_SHUTDOWN) || !timeo || 619 signal_pending(current)) 620 break; 621 } 622 623 release_sock(sk); 624 625 if (spliced) 626 return spliced; 627 628 return ret; 629} 630 631struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp) 632{ 633 struct sk_buff *skb; 634 635 /* The TCP header must be at least 32-bit aligned. */ 636 size = ALIGN(size, 4); 637 638 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); 639 if (skb) { 640 if (sk_wmem_schedule(sk, skb->truesize)) { 641 /* 642 * Make sure that we have exactly size bytes 643 * available to the caller, no more, no less. 644 */ 645 skb_reserve(skb, skb_tailroom(skb) - size); 646 return skb; 647 } 648 __kfree_skb(skb); 649 } else { 650 sk->sk_prot->enter_memory_pressure(sk); 651 sk_stream_moderate_sndbuf(sk); 652 } 653 return NULL; 654} 655 656static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, 657 size_t psize, int flags) 658{ 659 struct tcp_sock *tp = tcp_sk(sk); 660 int mss_now, size_goal; 661 int err; 662 ssize_t copied; 663 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 664 665 /* Wait for a connection to finish. */ 666 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 667 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 668 goto out_err; 669 670 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 671 672 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 673 size_goal = tp->xmit_size_goal; 674 copied = 0; 675 676 err = -EPIPE; 677 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 678 goto do_error; 679 680 while (psize > 0) { 681 struct sk_buff *skb = tcp_write_queue_tail(sk); 682 struct page *page = pages[poffset / PAGE_SIZE]; 683 int copy, i, can_coalesce; 684 int offset = poffset % PAGE_SIZE; 685 int size = min_t(size_t, psize, PAGE_SIZE - offset); 686 687 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { 688new_segment: 689 if (!sk_stream_memory_free(sk)) 690 goto wait_for_sndbuf; 691 692 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation); 693 if (!skb) 694 goto wait_for_memory; 695 696 skb_entail(sk, skb); 697 copy = size_goal; 698 } 699 700 if (copy > size) 701 copy = size; 702 703 i = skb_shinfo(skb)->nr_frags; 704 can_coalesce = skb_can_coalesce(skb, i, page, offset); 705 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 706 tcp_mark_push(tp, skb); 707 goto new_segment; 708 } 709 if (!sk_wmem_schedule(sk, copy)) 710 goto wait_for_memory; 711 712 if (can_coalesce) { 713 skb_shinfo(skb)->frags[i - 1].size += copy; 714 } else { 715 get_page(page); 716 skb_fill_page_desc(skb, i, page, offset, copy); 717 } 718 719 skb->len += copy; 720 skb->data_len += copy; 721 skb->truesize += copy; 722 sk->sk_wmem_queued += copy; 723 sk_mem_charge(sk, copy); 724 skb->ip_summed = CHECKSUM_PARTIAL; 725 tp->write_seq += copy; 726 TCP_SKB_CB(skb)->end_seq += copy; 727 skb_shinfo(skb)->gso_segs = 0; 728 729 if (!copied) 730 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH; 731 732 copied += copy; 733 poffset += copy; 734 if (!(psize -= copy)) 735 goto out; 736 737 if (skb->len < size_goal || (flags & MSG_OOB)) 738 continue; 739 740 if (forced_push(tp)) { 741 tcp_mark_push(tp, skb); 742 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 743 } else if (skb == tcp_send_head(sk)) 744 tcp_push_one(sk, mss_now); 745 continue; 746 747wait_for_sndbuf: 748 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 749wait_for_memory: 750 if (copied) 751 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 752 753 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 754 goto do_error; 755 756 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 757 size_goal = tp->xmit_size_goal; 758 } 759 760out: 761 if (copied) 762 tcp_push(sk, flags, mss_now, tp->nonagle); 763 return copied; 764 765do_error: 766 if (copied) 767 goto out; 768out_err: 769 return sk_stream_error(sk, flags, err); 770} 771 772ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, 773 size_t size, int flags) 774{ 775 ssize_t res; 776 struct sock *sk = sock->sk; 777 778 if (!(sk->sk_route_caps & NETIF_F_SG) || 779 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 780 return sock_no_sendpage(sock, page, offset, size, flags); 781 782 lock_sock(sk); 783 TCP_CHECK_TIMER(sk); 784 res = do_tcp_sendpages(sk, &page, offset, size, flags); 785 TCP_CHECK_TIMER(sk); 786 release_sock(sk); 787 return res; 788} 789 790#define TCP_PAGE(sk) (sk->sk_sndmsg_page) 791#define TCP_OFF(sk) (sk->sk_sndmsg_off) 792 793static inline int select_size(struct sock *sk) 794{ 795 struct tcp_sock *tp = tcp_sk(sk); 796 int tmp = tp->mss_cache; 797 798 if (sk->sk_route_caps & NETIF_F_SG) { 799 if (sk_can_gso(sk)) 800 tmp = 0; 801 else { 802 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 803 804 if (tmp >= pgbreak && 805 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 806 tmp = pgbreak; 807 } 808 } 809 810 return tmp; 811} 812 813int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, 814 size_t size) 815{ 816 struct sock *sk = sock->sk; 817 struct iovec *iov; 818 struct tcp_sock *tp = tcp_sk(sk); 819 struct sk_buff *skb; 820 int iovlen, flags; 821 int mss_now, size_goal; 822 int err, copied; 823 long timeo; 824 825 lock_sock(sk); 826 TCP_CHECK_TIMER(sk); 827 828 flags = msg->msg_flags; 829 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 830 831 /* Wait for a connection to finish. */ 832 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 833 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 834 goto out_err; 835 836 /* This should be in poll */ 837 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 838 839 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 840 size_goal = tp->xmit_size_goal; 841 842 /* Ok commence sending. */ 843 iovlen = msg->msg_iovlen; 844 iov = msg->msg_iov; 845 copied = 0; 846 847 err = -EPIPE; 848 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 849 goto do_error; 850 851 while (--iovlen >= 0) { 852 int seglen = iov->iov_len; 853 unsigned char __user *from = iov->iov_base; 854 855 iov++; 856 857 while (seglen > 0) { 858 int copy; 859 860 skb = tcp_write_queue_tail(sk); 861 862 if (!tcp_send_head(sk) || 863 (copy = size_goal - skb->len) <= 0) { 864 865new_segment: 866 /* Allocate new segment. If the interface is SG, 867 * allocate skb fitting to single page. 868 */ 869 if (!sk_stream_memory_free(sk)) 870 goto wait_for_sndbuf; 871 872 skb = sk_stream_alloc_skb(sk, select_size(sk), 873 sk->sk_allocation); 874 if (!skb) 875 goto wait_for_memory; 876 877 /* 878 * Check whether we can use HW checksum. 879 */ 880 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 881 skb->ip_summed = CHECKSUM_PARTIAL; 882 883 skb_entail(sk, skb); 884 copy = size_goal; 885 } 886 887 /* Try to append data to the end of skb. */ 888 if (copy > seglen) 889 copy = seglen; 890 891 /* Where to copy to? */ 892 if (skb_tailroom(skb) > 0) { 893 /* We have some space in skb head. Superb! */ 894 if (copy > skb_tailroom(skb)) 895 copy = skb_tailroom(skb); 896 if ((err = skb_add_data(skb, from, copy)) != 0) 897 goto do_fault; 898 } else { 899 int merge = 0; 900 int i = skb_shinfo(skb)->nr_frags; 901 struct page *page = TCP_PAGE(sk); 902 int off = TCP_OFF(sk); 903 904 if (skb_can_coalesce(skb, i, page, off) && 905 off != PAGE_SIZE) { 906 /* We can extend the last page 907 * fragment. */ 908 merge = 1; 909 } else if (i == MAX_SKB_FRAGS || 910 (!i && 911 !(sk->sk_route_caps & NETIF_F_SG))) { 912 /* Need to add new fragment and cannot 913 * do this because interface is non-SG, 914 * or because all the page slots are 915 * busy. */ 916 tcp_mark_push(tp, skb); 917 goto new_segment; 918 } else if (page) { 919 if (off == PAGE_SIZE) { 920 put_page(page); 921 TCP_PAGE(sk) = page = NULL; 922 off = 0; 923 } 924 } else 925 off = 0; 926 927 if (copy > PAGE_SIZE - off) 928 copy = PAGE_SIZE - off; 929 930 if (!sk_wmem_schedule(sk, copy)) 931 goto wait_for_memory; 932 933 if (!page) { 934 /* Allocate new cache page. */ 935 if (!(page = sk_stream_alloc_page(sk))) 936 goto wait_for_memory; 937 } 938 939 /* Time to copy data. We are close to 940 * the end! */ 941 err = skb_copy_to_page(sk, from, skb, page, 942 off, copy); 943 if (err) { 944 /* If this page was new, give it to the 945 * socket so it does not get leaked. 946 */ 947 if (!TCP_PAGE(sk)) { 948 TCP_PAGE(sk) = page; 949 TCP_OFF(sk) = 0; 950 } 951 goto do_error; 952 } 953 954 /* Update the skb. */ 955 if (merge) { 956 skb_shinfo(skb)->frags[i - 1].size += 957 copy; 958 } else { 959 skb_fill_page_desc(skb, i, page, off, copy); 960 if (TCP_PAGE(sk)) { 961 get_page(page); 962 } else if (off + copy < PAGE_SIZE) { 963 get_page(page); 964 TCP_PAGE(sk) = page; 965 } 966 } 967 968 TCP_OFF(sk) = off + copy; 969 } 970 971 if (!copied) 972 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH; 973 974 tp->write_seq += copy; 975 TCP_SKB_CB(skb)->end_seq += copy; 976 skb_shinfo(skb)->gso_segs = 0; 977 978 from += copy; 979 copied += copy; 980 if ((seglen -= copy) == 0 && iovlen == 0) 981 goto out; 982 983 if (skb->len < size_goal || (flags & MSG_OOB)) 984 continue; 985 986 if (forced_push(tp)) { 987 tcp_mark_push(tp, skb); 988 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 989 } else if (skb == tcp_send_head(sk)) 990 tcp_push_one(sk, mss_now); 991 continue; 992 993wait_for_sndbuf: 994 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 995wait_for_memory: 996 if (copied) 997 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 998 999 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 1000 goto do_error; 1001 1002 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 1003 size_goal = tp->xmit_size_goal; 1004 } 1005 } 1006 1007out: 1008 if (copied) 1009 tcp_push(sk, flags, mss_now, tp->nonagle); 1010 TCP_CHECK_TIMER(sk); 1011 release_sock(sk); 1012 return copied; 1013 1014do_fault: 1015 if (!skb->len) { 1016 tcp_unlink_write_queue(skb, sk); 1017 /* It is the one place in all of TCP, except connection 1018 * reset, where we can be unlinking the send_head. 1019 */ 1020 tcp_check_send_head(sk, skb); 1021 sk_wmem_free_skb(sk, skb); 1022 } 1023 1024do_error: 1025 if (copied) 1026 goto out; 1027out_err: 1028 err = sk_stream_error(sk, flags, err); 1029 TCP_CHECK_TIMER(sk); 1030 release_sock(sk); 1031 return err; 1032} 1033 1034/* 1035 * Handle reading urgent data. BSD has very simple semantics for 1036 * this, no blocking and very strange errors 8) 1037 */ 1038 1039static int tcp_recv_urg(struct sock *sk, long timeo, 1040 struct msghdr *msg, int len, int flags, 1041 int *addr_len) 1042{ 1043 struct tcp_sock *tp = tcp_sk(sk); 1044 1045 /* No URG data to read. */ 1046 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || 1047 tp->urg_data == TCP_URG_READ) 1048 return -EINVAL; /* Yes this is right ! */ 1049 1050 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) 1051 return -ENOTCONN; 1052 1053 if (tp->urg_data & TCP_URG_VALID) { 1054 int err = 0; 1055 char c = tp->urg_data; 1056 1057 if (!(flags & MSG_PEEK)) 1058 tp->urg_data = TCP_URG_READ; 1059 1060 /* Read urgent data. */ 1061 msg->msg_flags |= MSG_OOB; 1062 1063 if (len > 0) { 1064 if (!(flags & MSG_TRUNC)) 1065 err = memcpy_toiovec(msg->msg_iov, &c, 1); 1066 len = 1; 1067 } else 1068 msg->msg_flags |= MSG_TRUNC; 1069 1070 return err ? -EFAULT : len; 1071 } 1072 1073 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 1074 return 0; 1075 1076 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and 1077 * the available implementations agree in this case: 1078 * this call should never block, independent of the 1079 * blocking state of the socket. 1080 * Mike <pall@rz.uni-karlsruhe.de> 1081 */ 1082 return -EAGAIN; 1083} 1084 1085/* Clean up the receive buffer for full frames taken by the user, 1086 * then send an ACK if necessary. COPIED is the number of bytes 1087 * tcp_recvmsg has given to the user so far, it speeds up the 1088 * calculation of whether or not we must ACK for the sake of 1089 * a window update. 1090 */ 1091void tcp_cleanup_rbuf(struct sock *sk, int copied) 1092{ 1093 struct tcp_sock *tp = tcp_sk(sk); 1094 int time_to_ack = 0; 1095 1096#if TCP_DEBUG 1097 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); 1098 1099 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq)); 1100#endif 1101 1102 if (inet_csk_ack_scheduled(sk)) { 1103 const struct inet_connection_sock *icsk = inet_csk(sk); 1104 /* Delayed ACKs frequently hit locked sockets during bulk 1105 * receive. */ 1106 if (icsk->icsk_ack.blocked || 1107 /* Once-per-two-segments ACK was not sent by tcp_input.c */ 1108 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || 1109 /* 1110 * If this read emptied read buffer, we send ACK, if 1111 * connection is not bidirectional, user drained 1112 * receive buffer and there was a small segment 1113 * in queue. 1114 */ 1115 (copied > 0 && 1116 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || 1117 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && 1118 !icsk->icsk_ack.pingpong)) && 1119 !atomic_read(&sk->sk_rmem_alloc))) 1120 time_to_ack = 1; 1121 } 1122 1123 /* We send an ACK if we can now advertise a non-zero window 1124 * which has been raised "significantly". 1125 * 1126 * Even if window raised up to infinity, do not send window open ACK 1127 * in states, where we will not receive more. It is useless. 1128 */ 1129 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 1130 __u32 rcv_window_now = tcp_receive_window(tp); 1131 1132 /* Optimize, __tcp_select_window() is not cheap. */ 1133 if (2*rcv_window_now <= tp->window_clamp) { 1134 __u32 new_window = __tcp_select_window(sk); 1135 1136 /* Send ACK now, if this read freed lots of space 1137 * in our buffer. Certainly, new_window is new window. 1138 * We can advertise it now, if it is not less than current one. 1139 * "Lots" means "at least twice" here. 1140 */ 1141 if (new_window && new_window >= 2 * rcv_window_now) 1142 time_to_ack = 1; 1143 } 1144 } 1145 if (time_to_ack) 1146 tcp_send_ack(sk); 1147} 1148 1149static void tcp_prequeue_process(struct sock *sk) 1150{ 1151 struct sk_buff *skb; 1152 struct tcp_sock *tp = tcp_sk(sk); 1153 1154 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED); 1155 1156 /* RX process wants to run with disabled BHs, though it is not 1157 * necessary */ 1158 local_bh_disable(); 1159 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) 1160 sk->sk_backlog_rcv(sk, skb); 1161 local_bh_enable(); 1162 1163 /* Clear memory counter. */ 1164 tp->ucopy.memory = 0; 1165} 1166 1167static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 1168{ 1169 struct sk_buff *skb; 1170 u32 offset; 1171 1172 skb_queue_walk(&sk->sk_receive_queue, skb) { 1173 offset = seq - TCP_SKB_CB(skb)->seq; 1174 if (tcp_hdr(skb)->syn) 1175 offset--; 1176 if (offset < skb->len || tcp_hdr(skb)->fin) { 1177 *off = offset; 1178 return skb; 1179 } 1180 } 1181 return NULL; 1182} 1183 1184/* 1185 * This routine provides an alternative to tcp_recvmsg() for routines 1186 * that would like to handle copying from skbuffs directly in 'sendfile' 1187 * fashion. 1188 * Note: 1189 * - It is assumed that the socket was locked by the caller. 1190 * - The routine does not block. 1191 * - At present, there is no support for reading OOB data 1192 * or for 'peeking' the socket using this routine 1193 * (although both would be easy to implement). 1194 */ 1195int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 1196 sk_read_actor_t recv_actor) 1197{ 1198 struct sk_buff *skb; 1199 struct tcp_sock *tp = tcp_sk(sk); 1200 u32 seq = tp->copied_seq; 1201 u32 offset; 1202 int copied = 0; 1203 1204 if (sk->sk_state == TCP_LISTEN) 1205 return -ENOTCONN; 1206 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { 1207 if (offset < skb->len) { 1208 int used; 1209 size_t len; 1210 1211 len = skb->len - offset; 1212 /* Stop reading if we hit a patch of urgent data */ 1213 if (tp->urg_data) { 1214 u32 urg_offset = tp->urg_seq - seq; 1215 if (urg_offset < len) 1216 len = urg_offset; 1217 if (!len) 1218 break; 1219 } 1220 used = recv_actor(desc, skb, offset, len); 1221 if (used < 0) { 1222 if (!copied) 1223 copied = used; 1224 break; 1225 } else if (used <= len) { 1226 seq += used; 1227 copied += used; 1228 offset += used; 1229 } 1230 /* 1231 * If recv_actor drops the lock (e.g. TCP splice 1232 * receive) the skb pointer might be invalid when 1233 * getting here: tcp_collapse might have deleted it 1234 * while aggregating skbs from the socket queue. 1235 */ 1236 skb = tcp_recv_skb(sk, seq-1, &offset); 1237 if (!skb || (offset+1 != skb->len)) 1238 break; 1239 } 1240 if (tcp_hdr(skb)->fin) { 1241 sk_eat_skb(sk, skb, 0); 1242 ++seq; 1243 break; 1244 } 1245 sk_eat_skb(sk, skb, 0); 1246 if (!desc->count) 1247 break; 1248 } 1249 tp->copied_seq = seq; 1250 1251 tcp_rcv_space_adjust(sk); 1252 1253 /* Clean up data we have read: This will do ACK frames. */ 1254 if (copied > 0) 1255 tcp_cleanup_rbuf(sk, copied); 1256 return copied; 1257} 1258 1259/* 1260 * This routine copies from a sock struct into the user buffer. 1261 * 1262 * Technical note: in 2.3 we work on _locked_ socket, so that 1263 * tricks with *seq access order and skb->users are not required. 1264 * Probably, code can be easily improved even more. 1265 */ 1266 1267int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 1268 size_t len, int nonblock, int flags, int *addr_len) 1269{ 1270 struct tcp_sock *tp = tcp_sk(sk); 1271 int copied = 0; 1272 u32 peek_seq; 1273 u32 *seq; 1274 unsigned long used; 1275 int err; 1276 int target; /* Read at least this many bytes */ 1277 long timeo; 1278 struct task_struct *user_recv = NULL; 1279 int copied_early = 0; 1280 struct sk_buff *skb; 1281 1282 lock_sock(sk); 1283 1284 TCP_CHECK_TIMER(sk); 1285 1286 err = -ENOTCONN; 1287 if (sk->sk_state == TCP_LISTEN) 1288 goto out; 1289 1290 timeo = sock_rcvtimeo(sk, nonblock); 1291 1292 /* Urgent data needs to be handled specially. */ 1293 if (flags & MSG_OOB) 1294 goto recv_urg; 1295 1296 seq = &tp->copied_seq; 1297 if (flags & MSG_PEEK) { 1298 peek_seq = tp->copied_seq; 1299 seq = &peek_seq; 1300 } 1301 1302 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1303 1304#ifdef CONFIG_NET_DMA 1305 tp->ucopy.dma_chan = NULL; 1306 preempt_disable(); 1307 skb = skb_peek_tail(&sk->sk_receive_queue); 1308 { 1309 int available = 0; 1310 1311 if (skb) 1312 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); 1313 if ((available < target) && 1314 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && 1315 !sysctl_tcp_low_latency && 1316 __get_cpu_var(softnet_data).net_dma) { 1317 preempt_enable_no_resched(); 1318 tp->ucopy.pinned_list = 1319 dma_pin_iovec_pages(msg->msg_iov, len); 1320 } else { 1321 preempt_enable_no_resched(); 1322 } 1323 } 1324#endif 1325 1326 do { 1327 u32 offset; 1328 1329 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ 1330 if (tp->urg_data && tp->urg_seq == *seq) { 1331 if (copied) 1332 break; 1333 if (signal_pending(current)) { 1334 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; 1335 break; 1336 } 1337 } 1338 1339 /* Next get a buffer. */ 1340 1341 skb = skb_peek(&sk->sk_receive_queue); 1342 do { 1343 if (!skb) 1344 break; 1345 1346 /* Now that we have two receive queues this 1347 * shouldn't happen. 1348 */ 1349 if (before(*seq, TCP_SKB_CB(skb)->seq)) { 1350 printk(KERN_INFO "recvmsg bug: copied %X " 1351 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq); 1352 break; 1353 } 1354 offset = *seq - TCP_SKB_CB(skb)->seq; 1355 if (tcp_hdr(skb)->syn) 1356 offset--; 1357 if (offset < skb->len) 1358 goto found_ok_skb; 1359 if (tcp_hdr(skb)->fin) 1360 goto found_fin_ok; 1361 BUG_TRAP(flags & MSG_PEEK); 1362 skb = skb->next; 1363 } while (skb != (struct sk_buff *)&sk->sk_receive_queue); 1364 1365 /* Well, if we have backlog, try to process it now yet. */ 1366 1367 if (copied >= target && !sk->sk_backlog.tail) 1368 break; 1369 1370 if (copied) { 1371 if (sk->sk_err || 1372 sk->sk_state == TCP_CLOSE || 1373 (sk->sk_shutdown & RCV_SHUTDOWN) || 1374 !timeo || 1375 signal_pending(current) || 1376 (flags & MSG_PEEK)) 1377 break; 1378 } else { 1379 if (sock_flag(sk, SOCK_DONE)) 1380 break; 1381 1382 if (sk->sk_err) { 1383 copied = sock_error(sk); 1384 break; 1385 } 1386 1387 if (sk->sk_shutdown & RCV_SHUTDOWN) 1388 break; 1389 1390 if (sk->sk_state == TCP_CLOSE) { 1391 if (!sock_flag(sk, SOCK_DONE)) { 1392 /* This occurs when user tries to read 1393 * from never connected socket. 1394 */ 1395 copied = -ENOTCONN; 1396 break; 1397 } 1398 break; 1399 } 1400 1401 if (!timeo) { 1402 copied = -EAGAIN; 1403 break; 1404 } 1405 1406 if (signal_pending(current)) { 1407 copied = sock_intr_errno(timeo); 1408 break; 1409 } 1410 } 1411 1412 tcp_cleanup_rbuf(sk, copied); 1413 1414 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1415 /* Install new reader */ 1416 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1417 user_recv = current; 1418 tp->ucopy.task = user_recv; 1419 tp->ucopy.iov = msg->msg_iov; 1420 } 1421 1422 tp->ucopy.len = len; 1423 1424 BUG_TRAP(tp->copied_seq == tp->rcv_nxt || 1425 (flags & (MSG_PEEK | MSG_TRUNC))); 1426 1427 /* Ugly... If prequeue is not empty, we have to 1428 * process it before releasing socket, otherwise 1429 * order will be broken at second iteration. 1430 * More elegant solution is required!!! 1431 * 1432 * Look: we have the following (pseudo)queues: 1433 * 1434 * 1. packets in flight 1435 * 2. backlog 1436 * 3. prequeue 1437 * 4. receive_queue 1438 * 1439 * Each queue can be processed only if the next ones 1440 * are empty. At this point we have empty receive_queue. 1441 * But prequeue _can_ be not empty after 2nd iteration, 1442 * when we jumped to start of loop because backlog 1443 * processing added something to receive_queue. 1444 * We cannot release_sock(), because backlog contains 1445 * packets arrived _after_ prequeued ones. 1446 * 1447 * Shortly, algorithm is clear --- to process all 1448 * the queues in order. We could make it more directly, 1449 * requeueing packets from backlog to prequeue, if 1450 * is not empty. It is more elegant, but eats cycles, 1451 * unfortunately. 1452 */ 1453 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1454 goto do_prequeue; 1455 1456 /* __ Set realtime policy in scheduler __ */ 1457 } 1458 1459 if (copied >= target) { 1460 /* Do not sleep, just process backlog. */ 1461 release_sock(sk); 1462 lock_sock(sk); 1463 } else 1464 sk_wait_data(sk, &timeo); 1465 1466#ifdef CONFIG_NET_DMA 1467 tp->ucopy.wakeup = 0; 1468#endif 1469 1470 if (user_recv) { 1471 int chunk; 1472 1473 /* __ Restore normal policy in scheduler __ */ 1474 1475 if ((chunk = len - tp->ucopy.len) != 0) { 1476 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1477 len -= chunk; 1478 copied += chunk; 1479 } 1480 1481 if (tp->rcv_nxt == tp->copied_seq && 1482 !skb_queue_empty(&tp->ucopy.prequeue)) { 1483do_prequeue: 1484 tcp_prequeue_process(sk); 1485 1486 if ((chunk = len - tp->ucopy.len) != 0) { 1487 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1488 len -= chunk; 1489 copied += chunk; 1490 } 1491 } 1492 } 1493 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) { 1494 if (net_ratelimit()) 1495 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n", 1496 current->comm, task_pid_nr(current)); 1497 peek_seq = tp->copied_seq; 1498 } 1499 continue; 1500 1501 found_ok_skb: 1502 /* Ok so how much can we use? */ 1503 used = skb->len - offset; 1504 if (len < used) 1505 used = len; 1506 1507 /* Do we have urgent data here? */ 1508 if (tp->urg_data) { 1509 u32 urg_offset = tp->urg_seq - *seq; 1510 if (urg_offset < used) { 1511 if (!urg_offset) { 1512 if (!sock_flag(sk, SOCK_URGINLINE)) { 1513 ++*seq; 1514 offset++; 1515 used--; 1516 if (!used) 1517 goto skip_copy; 1518 } 1519 } else 1520 used = urg_offset; 1521 } 1522 } 1523 1524 if (!(flags & MSG_TRUNC)) { 1525#ifdef CONFIG_NET_DMA 1526 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) 1527 tp->ucopy.dma_chan = get_softnet_dma(); 1528 1529 if (tp->ucopy.dma_chan) { 1530 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec( 1531 tp->ucopy.dma_chan, skb, offset, 1532 msg->msg_iov, used, 1533 tp->ucopy.pinned_list); 1534 1535 if (tp->ucopy.dma_cookie < 0) { 1536 1537 printk(KERN_ALERT "dma_cookie < 0\n"); 1538 1539 /* Exception. Bailout! */ 1540 if (!copied) 1541 copied = -EFAULT; 1542 break; 1543 } 1544 if ((offset + used) == skb->len) 1545 copied_early = 1; 1546 1547 } else 1548#endif 1549 { 1550 err = skb_copy_datagram_iovec(skb, offset, 1551 msg->msg_iov, used); 1552 if (err) { 1553 /* Exception. Bailout! */ 1554 if (!copied) 1555 copied = -EFAULT; 1556 break; 1557 } 1558 } 1559 } 1560 1561 *seq += used; 1562 copied += used; 1563 len -= used; 1564 1565 tcp_rcv_space_adjust(sk); 1566 1567skip_copy: 1568 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1569 tp->urg_data = 0; 1570 tcp_fast_path_check(sk); 1571 } 1572 if (used + offset < skb->len) 1573 continue; 1574 1575 if (tcp_hdr(skb)->fin) 1576 goto found_fin_ok; 1577 if (!(flags & MSG_PEEK)) { 1578 sk_eat_skb(sk, skb, copied_early); 1579 copied_early = 0; 1580 } 1581 continue; 1582 1583 found_fin_ok: 1584 /* Process the FIN. */ 1585 ++*seq; 1586 if (!(flags & MSG_PEEK)) { 1587 sk_eat_skb(sk, skb, copied_early); 1588 copied_early = 0; 1589 } 1590 break; 1591 } while (len > 0); 1592 1593 if (user_recv) { 1594 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1595 int chunk; 1596 1597 tp->ucopy.len = copied > 0 ? len : 0; 1598 1599 tcp_prequeue_process(sk); 1600 1601 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1602 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1603 len -= chunk; 1604 copied += chunk; 1605 } 1606 } 1607 1608 tp->ucopy.task = NULL; 1609 tp->ucopy.len = 0; 1610 } 1611 1612#ifdef CONFIG_NET_DMA 1613 if (tp->ucopy.dma_chan) { 1614 dma_cookie_t done, used; 1615 1616 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1617 1618 while (dma_async_memcpy_complete(tp->ucopy.dma_chan, 1619 tp->ucopy.dma_cookie, &done, 1620 &used) == DMA_IN_PROGRESS) { 1621 /* do partial cleanup of sk_async_wait_queue */ 1622 while ((skb = skb_peek(&sk->sk_async_wait_queue)) && 1623 (dma_async_is_complete(skb->dma_cookie, done, 1624 used) == DMA_SUCCESS)) { 1625 __skb_dequeue(&sk->sk_async_wait_queue); 1626 kfree_skb(skb); 1627 } 1628 } 1629 1630 /* Safe to free early-copied skbs now */ 1631 __skb_queue_purge(&sk->sk_async_wait_queue); 1632 dma_chan_put(tp->ucopy.dma_chan); 1633 tp->ucopy.dma_chan = NULL; 1634 } 1635 if (tp->ucopy.pinned_list) { 1636 dma_unpin_iovec_pages(tp->ucopy.pinned_list); 1637 tp->ucopy.pinned_list = NULL; 1638 } 1639#endif 1640 1641 /* According to UNIX98, msg_name/msg_namelen are ignored 1642 * on connected socket. I was just happy when found this 8) --ANK 1643 */ 1644 1645 /* Clean up data we have read: This will do ACK frames. */ 1646 tcp_cleanup_rbuf(sk, copied); 1647 1648 TCP_CHECK_TIMER(sk); 1649 release_sock(sk); 1650 return copied; 1651 1652out: 1653 TCP_CHECK_TIMER(sk); 1654 release_sock(sk); 1655 return err; 1656 1657recv_urg: 1658 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len); 1659 goto out; 1660} 1661 1662void tcp_set_state(struct sock *sk, int state) 1663{ 1664 int oldstate = sk->sk_state; 1665 1666 switch (state) { 1667 case TCP_ESTABLISHED: 1668 if (oldstate != TCP_ESTABLISHED) 1669 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1670 break; 1671 1672 case TCP_CLOSE: 1673 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 1674 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS); 1675 1676 sk->sk_prot->unhash(sk); 1677 if (inet_csk(sk)->icsk_bind_hash && 1678 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 1679 inet_put_port(sk); 1680 /* fall through */ 1681 default: 1682 if (oldstate==TCP_ESTABLISHED) 1683 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1684 } 1685 1686 /* Change state AFTER socket is unhashed to avoid closed 1687 * socket sitting in hash tables. 1688 */ 1689 sk->sk_state = state; 1690 1691#ifdef STATE_TRACE 1692 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]); 1693#endif 1694} 1695EXPORT_SYMBOL_GPL(tcp_set_state); 1696 1697/* 1698 * State processing on a close. This implements the state shift for 1699 * sending our FIN frame. Note that we only send a FIN for some 1700 * states. A shutdown() may have already sent the FIN, or we may be 1701 * closed. 1702 */ 1703 1704static const unsigned char new_state[16] = { 1705 /* current state: new state: action: */ 1706 /* (Invalid) */ TCP_CLOSE, 1707 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1708 /* TCP_SYN_SENT */ TCP_CLOSE, 1709 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1710 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, 1711 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, 1712 /* TCP_TIME_WAIT */ TCP_CLOSE, 1713 /* TCP_CLOSE */ TCP_CLOSE, 1714 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, 1715 /* TCP_LAST_ACK */ TCP_LAST_ACK, 1716 /* TCP_LISTEN */ TCP_CLOSE, 1717 /* TCP_CLOSING */ TCP_CLOSING, 1718}; 1719 1720static int tcp_close_state(struct sock *sk) 1721{ 1722 int next = (int)new_state[sk->sk_state]; 1723 int ns = next & TCP_STATE_MASK; 1724 1725 tcp_set_state(sk, ns); 1726 1727 return next & TCP_ACTION_FIN; 1728} 1729 1730/* 1731 * Shutdown the sending side of a connection. Much like close except 1732 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD). 1733 */ 1734 1735void tcp_shutdown(struct sock *sk, int how) 1736{ 1737 /* We need to grab some memory, and put together a FIN, 1738 * and then put it into the queue to be sent. 1739 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 1740 */ 1741 if (!(how & SEND_SHUTDOWN)) 1742 return; 1743 1744 /* If we've already sent a FIN, or it's a closed state, skip this. */ 1745 if ((1 << sk->sk_state) & 1746 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 1747 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 1748 /* Clear out any half completed packets. FIN if needed. */ 1749 if (tcp_close_state(sk)) 1750 tcp_send_fin(sk); 1751 } 1752} 1753 1754void tcp_close(struct sock *sk, long timeout) 1755{ 1756 struct sk_buff *skb; 1757 int data_was_unread = 0; 1758 int state; 1759 1760 lock_sock(sk); 1761 sk->sk_shutdown = SHUTDOWN_MASK; 1762 1763 if (sk->sk_state == TCP_LISTEN) { 1764 tcp_set_state(sk, TCP_CLOSE); 1765 1766 /* Special case. */ 1767 inet_csk_listen_stop(sk); 1768 1769 goto adjudge_to_death; 1770 } 1771 1772 /* We need to flush the recv. buffs. We do this only on the 1773 * descriptor close, not protocol-sourced closes, because the 1774 * reader process may not have drained the data yet! 1775 */ 1776 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 1777 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq - 1778 tcp_hdr(skb)->fin; 1779 data_was_unread += len; 1780 __kfree_skb(skb); 1781 } 1782 1783 sk_mem_reclaim(sk); 1784 1785 /* As outlined in RFC 2525, section 2.17, we send a RST here because 1786 * data was lost. To witness the awful effects of the old behavior of 1787 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk 1788 * GET in an FTP client, suspend the process, wait for the client to 1789 * advertise a zero window, then kill -9 the FTP client, wheee... 1790 * Note: timeout is always zero in such a case. 1791 */ 1792 if (data_was_unread) { 1793 /* Unread data was tossed, zap the connection. */ 1794 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE); 1795 tcp_set_state(sk, TCP_CLOSE); 1796 tcp_send_active_reset(sk, GFP_KERNEL); 1797 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 1798 /* Check zero linger _after_ checking for unread data. */ 1799 sk->sk_prot->disconnect(sk, 0); 1800 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA); 1801 } else if (tcp_close_state(sk)) { 1802 /* We FIN if the application ate all the data before 1803 * zapping the connection. 1804 */ 1805 1806 /* RED-PEN. Formally speaking, we have broken TCP state 1807 * machine. State transitions: 1808 * 1809 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 1810 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 1811 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 1812 * 1813 * are legal only when FIN has been sent (i.e. in window), 1814 * rather than queued out of window. Purists blame. 1815 * 1816 * F.e. "RFC state" is ESTABLISHED, 1817 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 1818 * 1819 * The visible declinations are that sometimes 1820 * we enter time-wait state, when it is not required really 1821 * (harmless), do not send active resets, when they are 1822 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 1823 * they look as CLOSING or LAST_ACK for Linux) 1824 * Probably, I missed some more holelets. 1825 * --ANK 1826 */ 1827 tcp_send_fin(sk); 1828 } 1829 1830 sk_stream_wait_close(sk, timeout); 1831 1832adjudge_to_death: 1833 state = sk->sk_state; 1834 sock_hold(sk); 1835 sock_orphan(sk); 1836 atomic_inc(sk->sk_prot->orphan_count); 1837 1838 /* It is the last release_sock in its life. It will remove backlog. */ 1839 release_sock(sk); 1840 1841 1842 /* Now socket is owned by kernel and we acquire BH lock 1843 to finish close. No need to check for user refs. 1844 */ 1845 local_bh_disable(); 1846 bh_lock_sock(sk); 1847 BUG_TRAP(!sock_owned_by_user(sk)); 1848 1849 /* Have we already been destroyed by a softirq or backlog? */ 1850 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) 1851 goto out; 1852 1853 /* This is a (useful) BSD violating of the RFC. There is a 1854 * problem with TCP as specified in that the other end could 1855 * keep a socket open forever with no application left this end. 1856 * We use a 3 minute timeout (about the same as BSD) then kill 1857 * our end. If they send after that then tough - BUT: long enough 1858 * that we won't make the old 4*rto = almost no time - whoops 1859 * reset mistake. 1860 * 1861 * Nope, it was not mistake. It is really desired behaviour 1862 * f.e. on http servers, when such sockets are useless, but 1863 * consume significant resources. Let's do it with special 1864 * linger2 option. --ANK 1865 */ 1866 1867 if (sk->sk_state == TCP_FIN_WAIT2) { 1868 struct tcp_sock *tp = tcp_sk(sk); 1869 if (tp->linger2 < 0) { 1870 tcp_set_state(sk, TCP_CLOSE); 1871 tcp_send_active_reset(sk, GFP_ATOMIC); 1872 NET_INC_STATS_BH(sock_net(sk), 1873 LINUX_MIB_TCPABORTONLINGER); 1874 } else { 1875 const int tmo = tcp_fin_time(sk); 1876 1877 if (tmo > TCP_TIMEWAIT_LEN) { 1878 inet_csk_reset_keepalive_timer(sk, 1879 tmo - TCP_TIMEWAIT_LEN); 1880 } else { 1881 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); 1882 goto out; 1883 } 1884 } 1885 } 1886 if (sk->sk_state != TCP_CLOSE) { 1887 sk_mem_reclaim(sk); 1888 if (tcp_too_many_orphans(sk, 1889 atomic_read(sk->sk_prot->orphan_count))) { 1890 if (net_ratelimit()) 1891 printk(KERN_INFO "TCP: too many of orphaned " 1892 "sockets\n"); 1893 tcp_set_state(sk, TCP_CLOSE); 1894 tcp_send_active_reset(sk, GFP_ATOMIC); 1895 NET_INC_STATS_BH(sock_net(sk), 1896 LINUX_MIB_TCPABORTONMEMORY); 1897 } 1898 } 1899 1900 if (sk->sk_state == TCP_CLOSE) 1901 inet_csk_destroy_sock(sk); 1902 /* Otherwise, socket is reprieved until protocol close. */ 1903 1904out: 1905 bh_unlock_sock(sk); 1906 local_bh_enable(); 1907 sock_put(sk); 1908} 1909 1910/* These states need RST on ABORT according to RFC793 */ 1911 1912static inline int tcp_need_reset(int state) 1913{ 1914 return (1 << state) & 1915 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 1916 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 1917} 1918 1919int tcp_disconnect(struct sock *sk, int flags) 1920{ 1921 struct inet_sock *inet = inet_sk(sk); 1922 struct inet_connection_sock *icsk = inet_csk(sk); 1923 struct tcp_sock *tp = tcp_sk(sk); 1924 int err = 0; 1925 int old_state = sk->sk_state; 1926 1927 if (old_state != TCP_CLOSE) 1928 tcp_set_state(sk, TCP_CLOSE); 1929 1930 /* ABORT function of RFC793 */ 1931 if (old_state == TCP_LISTEN) { 1932 inet_csk_listen_stop(sk); 1933 } else if (tcp_need_reset(old_state) || 1934 (tp->snd_nxt != tp->write_seq && 1935 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 1936 /* The last check adjusts for discrepancy of Linux wrt. RFC 1937 * states 1938 */ 1939 tcp_send_active_reset(sk, gfp_any()); 1940 sk->sk_err = ECONNRESET; 1941 } else if (old_state == TCP_SYN_SENT) 1942 sk->sk_err = ECONNRESET; 1943 1944 tcp_clear_xmit_timers(sk); 1945 __skb_queue_purge(&sk->sk_receive_queue); 1946 tcp_write_queue_purge(sk); 1947 __skb_queue_purge(&tp->out_of_order_queue); 1948#ifdef CONFIG_NET_DMA 1949 __skb_queue_purge(&sk->sk_async_wait_queue); 1950#endif 1951 1952 inet->dport = 0; 1953 1954 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 1955 inet_reset_saddr(sk); 1956 1957 sk->sk_shutdown = 0; 1958 sock_reset_flag(sk, SOCK_DONE); 1959 tp->srtt = 0; 1960 if ((tp->write_seq += tp->max_window + 2) == 0) 1961 tp->write_seq = 1; 1962 icsk->icsk_backoff = 0; 1963 tp->snd_cwnd = 2; 1964 icsk->icsk_probes_out = 0; 1965 tp->packets_out = 0; 1966 tp->snd_ssthresh = 0x7fffffff; 1967 tp->snd_cwnd_cnt = 0; 1968 tp->bytes_acked = 0; 1969 tcp_set_ca_state(sk, TCP_CA_Open); 1970 tcp_clear_retrans(tp); 1971 inet_csk_delack_init(sk); 1972 tcp_init_send_head(sk); 1973 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); 1974 __sk_dst_reset(sk); 1975 1976 BUG_TRAP(!inet->num || icsk->icsk_bind_hash); 1977 1978 sk->sk_error_report(sk); 1979 return err; 1980} 1981 1982/* 1983 * Socket option code for TCP. 1984 */ 1985static int do_tcp_setsockopt(struct sock *sk, int level, 1986 int optname, char __user *optval, int optlen) 1987{ 1988 struct tcp_sock *tp = tcp_sk(sk); 1989 struct inet_connection_sock *icsk = inet_csk(sk); 1990 int val; 1991 int err = 0; 1992 1993 /* This is a string value all the others are int's */ 1994 if (optname == TCP_CONGESTION) { 1995 char name[TCP_CA_NAME_MAX]; 1996 1997 if (optlen < 1) 1998 return -EINVAL; 1999 2000 val = strncpy_from_user(name, optval, 2001 min(TCP_CA_NAME_MAX-1, optlen)); 2002 if (val < 0) 2003 return -EFAULT; 2004 name[val] = 0; 2005 2006 lock_sock(sk); 2007 err = tcp_set_congestion_control(sk, name); 2008 release_sock(sk); 2009 return err; 2010 } 2011 2012 if (optlen < sizeof(int)) 2013 return -EINVAL; 2014 2015 if (get_user(val, (int __user *)optval)) 2016 return -EFAULT; 2017 2018 lock_sock(sk); 2019 2020 switch (optname) { 2021 case TCP_MAXSEG: 2022 /* Values greater than interface MTU won't take effect. However 2023 * at the point when this call is done we typically don't yet 2024 * know which interface is going to be used */ 2025 if (val < 8 || val > MAX_TCP_WINDOW) { 2026 err = -EINVAL; 2027 break; 2028 } 2029 tp->rx_opt.user_mss = val; 2030 break; 2031 2032 case TCP_NODELAY: 2033 if (val) { 2034 /* TCP_NODELAY is weaker than TCP_CORK, so that 2035 * this option on corked socket is remembered, but 2036 * it is not activated until cork is cleared. 2037 * 2038 * However, when TCP_NODELAY is set we make 2039 * an explicit push, which overrides even TCP_CORK 2040 * for currently queued segments. 2041 */ 2042 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 2043 tcp_push_pending_frames(sk); 2044 } else { 2045 tp->nonagle &= ~TCP_NAGLE_OFF; 2046 } 2047 break; 2048 2049 case TCP_CORK: 2050 /* When set indicates to always queue non-full frames. 2051 * Later the user clears this option and we transmit 2052 * any pending partial frames in the queue. This is 2053 * meant to be used alongside sendfile() to get properly 2054 * filled frames when the user (for example) must write 2055 * out headers with a write() call first and then use 2056 * sendfile to send out the data parts. 2057 * 2058 * TCP_CORK can be set together with TCP_NODELAY and it is 2059 * stronger than TCP_NODELAY. 2060 */ 2061 if (val) { 2062 tp->nonagle |= TCP_NAGLE_CORK; 2063 } else { 2064 tp->nonagle &= ~TCP_NAGLE_CORK; 2065 if (tp->nonagle&TCP_NAGLE_OFF) 2066 tp->nonagle |= TCP_NAGLE_PUSH; 2067 tcp_push_pending_frames(sk); 2068 } 2069 break; 2070 2071 case TCP_KEEPIDLE: 2072 if (val < 1 || val > MAX_TCP_KEEPIDLE) 2073 err = -EINVAL; 2074 else { 2075 tp->keepalive_time = val * HZ; 2076 if (sock_flag(sk, SOCK_KEEPOPEN) && 2077 !((1 << sk->sk_state) & 2078 (TCPF_CLOSE | TCPF_LISTEN))) { 2079 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp; 2080 if (tp->keepalive_time > elapsed) 2081 elapsed = tp->keepalive_time - elapsed; 2082 else 2083 elapsed = 0; 2084 inet_csk_reset_keepalive_timer(sk, elapsed); 2085 } 2086 } 2087 break; 2088 case TCP_KEEPINTVL: 2089 if (val < 1 || val > MAX_TCP_KEEPINTVL) 2090 err = -EINVAL; 2091 else 2092 tp->keepalive_intvl = val * HZ; 2093 break; 2094 case TCP_KEEPCNT: 2095 if (val < 1 || val > MAX_TCP_KEEPCNT) 2096 err = -EINVAL; 2097 else 2098 tp->keepalive_probes = val; 2099 break; 2100 case TCP_SYNCNT: 2101 if (val < 1 || val > MAX_TCP_SYNCNT) 2102 err = -EINVAL; 2103 else 2104 icsk->icsk_syn_retries = val; 2105 break; 2106 2107 case TCP_LINGER2: 2108 if (val < 0) 2109 tp->linger2 = -1; 2110 else if (val > sysctl_tcp_fin_timeout / HZ) 2111 tp->linger2 = 0; 2112 else 2113 tp->linger2 = val * HZ; 2114 break; 2115 2116 case TCP_DEFER_ACCEPT: 2117 icsk->icsk_accept_queue.rskq_defer_accept = 0; 2118 if (val > 0) { 2119 /* Translate value in seconds to number of 2120 * retransmits */ 2121 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 && 2122 val > ((TCP_TIMEOUT_INIT / HZ) << 2123 icsk->icsk_accept_queue.rskq_defer_accept)) 2124 icsk->icsk_accept_queue.rskq_defer_accept++; 2125 icsk->icsk_accept_queue.rskq_defer_accept++; 2126 } 2127 break; 2128 2129 case TCP_WINDOW_CLAMP: 2130 if (!val) { 2131 if (sk->sk_state != TCP_CLOSE) { 2132 err = -EINVAL; 2133 break; 2134 } 2135 tp->window_clamp = 0; 2136 } else 2137 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 2138 SOCK_MIN_RCVBUF / 2 : val; 2139 break; 2140 2141 case TCP_QUICKACK: 2142 if (!val) { 2143 icsk->icsk_ack.pingpong = 1; 2144 } else { 2145 icsk->icsk_ack.pingpong = 0; 2146 if ((1 << sk->sk_state) & 2147 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 2148 inet_csk_ack_scheduled(sk)) { 2149 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 2150 tcp_cleanup_rbuf(sk, 1); 2151 if (!(val & 1)) 2152 icsk->icsk_ack.pingpong = 1; 2153 } 2154 } 2155 break; 2156 2157#ifdef CONFIG_TCP_MD5SIG 2158 case TCP_MD5SIG: 2159 /* Read the IP->Key mappings from userspace */ 2160 err = tp->af_specific->md5_parse(sk, optval, optlen); 2161 break; 2162#endif 2163 2164 default: 2165 err = -ENOPROTOOPT; 2166 break; 2167 } 2168 2169 release_sock(sk); 2170 return err; 2171} 2172 2173int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 2174 int optlen) 2175{ 2176 struct inet_connection_sock *icsk = inet_csk(sk); 2177 2178 if (level != SOL_TCP) 2179 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 2180 optval, optlen); 2181 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2182} 2183 2184#ifdef CONFIG_COMPAT 2185int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 2186 char __user *optval, int optlen) 2187{ 2188 if (level != SOL_TCP) 2189 return inet_csk_compat_setsockopt(sk, level, optname, 2190 optval, optlen); 2191 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2192} 2193 2194EXPORT_SYMBOL(compat_tcp_setsockopt); 2195#endif 2196 2197/* Return information about state of tcp endpoint in API format. */ 2198void tcp_get_info(struct sock *sk, struct tcp_info *info) 2199{ 2200 struct tcp_sock *tp = tcp_sk(sk); 2201 const struct inet_connection_sock *icsk = inet_csk(sk); 2202 u32 now = tcp_time_stamp; 2203 2204 memset(info, 0, sizeof(*info)); 2205 2206 info->tcpi_state = sk->sk_state; 2207 info->tcpi_ca_state = icsk->icsk_ca_state; 2208 info->tcpi_retransmits = icsk->icsk_retransmits; 2209 info->tcpi_probes = icsk->icsk_probes_out; 2210 info->tcpi_backoff = icsk->icsk_backoff; 2211 2212 if (tp->rx_opt.tstamp_ok) 2213 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2214 if (tcp_is_sack(tp)) 2215 info->tcpi_options |= TCPI_OPT_SACK; 2216 if (tp->rx_opt.wscale_ok) { 2217 info->tcpi_options |= TCPI_OPT_WSCALE; 2218 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2219 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2220 } 2221 2222 if (tp->ecn_flags&TCP_ECN_OK) 2223 info->tcpi_options |= TCPI_OPT_ECN; 2224 2225 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2226 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2227 info->tcpi_snd_mss = tp->mss_cache; 2228 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2229 2230 if (sk->sk_state == TCP_LISTEN) { 2231 info->tcpi_unacked = sk->sk_ack_backlog; 2232 info->tcpi_sacked = sk->sk_max_ack_backlog; 2233 } else { 2234 info->tcpi_unacked = tp->packets_out; 2235 info->tcpi_sacked = tp->sacked_out; 2236 } 2237 info->tcpi_lost = tp->lost_out; 2238 info->tcpi_retrans = tp->retrans_out; 2239 info->tcpi_fackets = tp->fackets_out; 2240 2241 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2242 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2243 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2244 2245 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2246 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2247 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3; 2248 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2; 2249 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2250 info->tcpi_snd_cwnd = tp->snd_cwnd; 2251 info->tcpi_advmss = tp->advmss; 2252 info->tcpi_reordering = tp->reordering; 2253 2254 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2255 info->tcpi_rcv_space = tp->rcvq_space.space; 2256 2257 info->tcpi_total_retrans = tp->total_retrans; 2258} 2259 2260EXPORT_SYMBOL_GPL(tcp_get_info); 2261 2262static int do_tcp_getsockopt(struct sock *sk, int level, 2263 int optname, char __user *optval, int __user *optlen) 2264{ 2265 struct inet_connection_sock *icsk = inet_csk(sk); 2266 struct tcp_sock *tp = tcp_sk(sk); 2267 int val, len; 2268 2269 if (get_user(len, optlen)) 2270 return -EFAULT; 2271 2272 len = min_t(unsigned int, len, sizeof(int)); 2273 2274 if (len < 0) 2275 return -EINVAL; 2276 2277 switch (optname) { 2278 case TCP_MAXSEG: 2279 val = tp->mss_cache; 2280 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2281 val = tp->rx_opt.user_mss; 2282 break; 2283 case TCP_NODELAY: 2284 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2285 break; 2286 case TCP_CORK: 2287 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2288 break; 2289 case TCP_KEEPIDLE: 2290 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ; 2291 break; 2292 case TCP_KEEPINTVL: 2293 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ; 2294 break; 2295 case TCP_KEEPCNT: 2296 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes; 2297 break; 2298 case TCP_SYNCNT: 2299 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2300 break; 2301 case TCP_LINGER2: 2302 val = tp->linger2; 2303 if (val >= 0) 2304 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2305 break; 2306 case TCP_DEFER_ACCEPT: 2307 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 : 2308 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1)); 2309 break; 2310 case TCP_WINDOW_CLAMP: 2311 val = tp->window_clamp; 2312 break; 2313 case TCP_INFO: { 2314 struct tcp_info info; 2315 2316 if (get_user(len, optlen)) 2317 return -EFAULT; 2318 2319 tcp_get_info(sk, &info); 2320 2321 len = min_t(unsigned int, len, sizeof(info)); 2322 if (put_user(len, optlen)) 2323 return -EFAULT; 2324 if (copy_to_user(optval, &info, len)) 2325 return -EFAULT; 2326 return 0; 2327 } 2328 case TCP_QUICKACK: 2329 val = !icsk->icsk_ack.pingpong; 2330 break; 2331 2332 case TCP_CONGESTION: 2333 if (get_user(len, optlen)) 2334 return -EFAULT; 2335 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2336 if (put_user(len, optlen)) 2337 return -EFAULT; 2338 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2339 return -EFAULT; 2340 return 0; 2341 default: 2342 return -ENOPROTOOPT; 2343 } 2344 2345 if (put_user(len, optlen)) 2346 return -EFAULT; 2347 if (copy_to_user(optval, &val, len)) 2348 return -EFAULT; 2349 return 0; 2350} 2351 2352int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2353 int __user *optlen) 2354{ 2355 struct inet_connection_sock *icsk = inet_csk(sk); 2356 2357 if (level != SOL_TCP) 2358 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2359 optval, optlen); 2360 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2361} 2362 2363#ifdef CONFIG_COMPAT 2364int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2365 char __user *optval, int __user *optlen) 2366{ 2367 if (level != SOL_TCP) 2368 return inet_csk_compat_getsockopt(sk, level, optname, 2369 optval, optlen); 2370 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2371} 2372 2373EXPORT_SYMBOL(compat_tcp_getsockopt); 2374#endif 2375 2376struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features) 2377{ 2378 struct sk_buff *segs = ERR_PTR(-EINVAL); 2379 struct tcphdr *th; 2380 unsigned thlen; 2381 unsigned int seq; 2382 __be32 delta; 2383 unsigned int oldlen; 2384 unsigned int len; 2385 2386 if (!pskb_may_pull(skb, sizeof(*th))) 2387 goto out; 2388 2389 th = tcp_hdr(skb); 2390 thlen = th->doff * 4; 2391 if (thlen < sizeof(*th)) 2392 goto out; 2393 2394 if (!pskb_may_pull(skb, thlen)) 2395 goto out; 2396 2397 oldlen = (u16)~skb->len; 2398 __skb_pull(skb, thlen); 2399 2400 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 2401 /* Packet is from an untrusted source, reset gso_segs. */ 2402 int type = skb_shinfo(skb)->gso_type; 2403 int mss; 2404 2405 if (unlikely(type & 2406 ~(SKB_GSO_TCPV4 | 2407 SKB_GSO_DODGY | 2408 SKB_GSO_TCP_ECN | 2409 SKB_GSO_TCPV6 | 2410 0) || 2411 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) 2412 goto out; 2413 2414 mss = skb_shinfo(skb)->gso_size; 2415 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); 2416 2417 segs = NULL; 2418 goto out; 2419 } 2420 2421 segs = skb_segment(skb, features); 2422 if (IS_ERR(segs)) 2423 goto out; 2424 2425 len = skb_shinfo(skb)->gso_size; 2426 delta = htonl(oldlen + (thlen + len)); 2427 2428 skb = segs; 2429 th = tcp_hdr(skb); 2430 seq = ntohl(th->seq); 2431 2432 do { 2433 th->fin = th->psh = 0; 2434 2435 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2436 (__force u32)delta)); 2437 if (skb->ip_summed != CHECKSUM_PARTIAL) 2438 th->check = 2439 csum_fold(csum_partial(skb_transport_header(skb), 2440 thlen, skb->csum)); 2441 2442 seq += len; 2443 skb = skb->next; 2444 th = tcp_hdr(skb); 2445 2446 th->seq = htonl(seq); 2447 th->cwr = 0; 2448 } while (skb->next); 2449 2450 delta = htonl(oldlen + (skb->tail - skb->transport_header) + 2451 skb->data_len); 2452 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2453 (__force u32)delta)); 2454 if (skb->ip_summed != CHECKSUM_PARTIAL) 2455 th->check = csum_fold(csum_partial(skb_transport_header(skb), 2456 thlen, skb->csum)); 2457 2458out: 2459 return segs; 2460} 2461EXPORT_SYMBOL(tcp_tso_segment); 2462 2463#ifdef CONFIG_TCP_MD5SIG 2464static unsigned long tcp_md5sig_users; 2465static struct tcp_md5sig_pool **tcp_md5sig_pool; 2466static DEFINE_SPINLOCK(tcp_md5sig_pool_lock); 2467 2468int tcp_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key, 2469 int bplen, 2470 struct tcphdr *th, unsigned int tcplen, 2471 struct tcp_md5sig_pool *hp) 2472{ 2473 struct scatterlist sg[4]; 2474 __u16 data_len; 2475 int block = 0; 2476 __sum16 cksum; 2477 struct hash_desc *desc = &hp->md5_desc; 2478 int err; 2479 unsigned int nbytes = 0; 2480 2481 sg_init_table(sg, 4); 2482 2483 /* 1. The TCP pseudo-header */ 2484 sg_set_buf(&sg[block++], &hp->md5_blk, bplen); 2485 nbytes += bplen; 2486 2487 /* 2. The TCP header, excluding options, and assuming a 2488 * checksum of zero 2489 */ 2490 cksum = th->check; 2491 th->check = 0; 2492 sg_set_buf(&sg[block++], th, sizeof(*th)); 2493 nbytes += sizeof(*th); 2494 2495 /* 3. The TCP segment data (if any) */ 2496 data_len = tcplen - (th->doff << 2); 2497 if (data_len > 0) { 2498 u8 *data = (u8 *)th + (th->doff << 2); 2499 sg_set_buf(&sg[block++], data, data_len); 2500 nbytes += data_len; 2501 } 2502 2503 /* 4. an independently-specified key or password, known to both 2504 * TCPs and presumably connection-specific 2505 */ 2506 sg_set_buf(&sg[block++], key->key, key->keylen); 2507 nbytes += key->keylen; 2508 2509 sg_mark_end(&sg[block - 1]); 2510 2511 /* Now store the hash into the packet */ 2512 err = crypto_hash_init(desc); 2513 if (err) { 2514 if (net_ratelimit()) 2515 printk(KERN_WARNING "%s(): hash_init failed\n", __func__); 2516 return -1; 2517 } 2518 err = crypto_hash_update(desc, sg, nbytes); 2519 if (err) { 2520 if (net_ratelimit()) 2521 printk(KERN_WARNING "%s(): hash_update failed\n", __func__); 2522 return -1; 2523 } 2524 err = crypto_hash_final(desc, md5_hash); 2525 if (err) { 2526 if (net_ratelimit()) 2527 printk(KERN_WARNING "%s(): hash_final failed\n", __func__); 2528 return -1; 2529 } 2530 2531 /* Reset header */ 2532 th->check = cksum; 2533 2534 return 0; 2535} 2536EXPORT_SYMBOL(tcp_calc_md5_hash); 2537 2538static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool) 2539{ 2540 int cpu; 2541 for_each_possible_cpu(cpu) { 2542 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu); 2543 if (p) { 2544 if (p->md5_desc.tfm) 2545 crypto_free_hash(p->md5_desc.tfm); 2546 kfree(p); 2547 p = NULL; 2548 } 2549 } 2550 free_percpu(pool); 2551} 2552 2553void tcp_free_md5sig_pool(void) 2554{ 2555 struct tcp_md5sig_pool **pool = NULL; 2556 2557 spin_lock_bh(&tcp_md5sig_pool_lock); 2558 if (--tcp_md5sig_users == 0) { 2559 pool = tcp_md5sig_pool; 2560 tcp_md5sig_pool = NULL; 2561 } 2562 spin_unlock_bh(&tcp_md5sig_pool_lock); 2563 if (pool) 2564 __tcp_free_md5sig_pool(pool); 2565} 2566 2567EXPORT_SYMBOL(tcp_free_md5sig_pool); 2568 2569static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void) 2570{ 2571 int cpu; 2572 struct tcp_md5sig_pool **pool; 2573 2574 pool = alloc_percpu(struct tcp_md5sig_pool *); 2575 if (!pool) 2576 return NULL; 2577 2578 for_each_possible_cpu(cpu) { 2579 struct tcp_md5sig_pool *p; 2580 struct crypto_hash *hash; 2581 2582 p = kzalloc(sizeof(*p), GFP_KERNEL); 2583 if (!p) 2584 goto out_free; 2585 *per_cpu_ptr(pool, cpu) = p; 2586 2587 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 2588 if (!hash || IS_ERR(hash)) 2589 goto out_free; 2590 2591 p->md5_desc.tfm = hash; 2592 } 2593 return pool; 2594out_free: 2595 __tcp_free_md5sig_pool(pool); 2596 return NULL; 2597} 2598 2599struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void) 2600{ 2601 struct tcp_md5sig_pool **pool; 2602 int alloc = 0; 2603 2604retry: 2605 spin_lock_bh(&tcp_md5sig_pool_lock); 2606 pool = tcp_md5sig_pool; 2607 if (tcp_md5sig_users++ == 0) { 2608 alloc = 1; 2609 spin_unlock_bh(&tcp_md5sig_pool_lock); 2610 } else if (!pool) { 2611 tcp_md5sig_users--; 2612 spin_unlock_bh(&tcp_md5sig_pool_lock); 2613 cpu_relax(); 2614 goto retry; 2615 } else 2616 spin_unlock_bh(&tcp_md5sig_pool_lock); 2617 2618 if (alloc) { 2619 /* we cannot hold spinlock here because this may sleep. */ 2620 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool(); 2621 spin_lock_bh(&tcp_md5sig_pool_lock); 2622 if (!p) { 2623 tcp_md5sig_users--; 2624 spin_unlock_bh(&tcp_md5sig_pool_lock); 2625 return NULL; 2626 } 2627 pool = tcp_md5sig_pool; 2628 if (pool) { 2629 /* oops, it has already been assigned. */ 2630 spin_unlock_bh(&tcp_md5sig_pool_lock); 2631 __tcp_free_md5sig_pool(p); 2632 } else { 2633 tcp_md5sig_pool = pool = p; 2634 spin_unlock_bh(&tcp_md5sig_pool_lock); 2635 } 2636 } 2637 return pool; 2638} 2639 2640EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 2641 2642struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu) 2643{ 2644 struct tcp_md5sig_pool **p; 2645 spin_lock_bh(&tcp_md5sig_pool_lock); 2646 p = tcp_md5sig_pool; 2647 if (p) 2648 tcp_md5sig_users++; 2649 spin_unlock_bh(&tcp_md5sig_pool_lock); 2650 return (p ? *per_cpu_ptr(p, cpu) : NULL); 2651} 2652 2653EXPORT_SYMBOL(__tcp_get_md5sig_pool); 2654 2655void __tcp_put_md5sig_pool(void) 2656{ 2657 tcp_free_md5sig_pool(); 2658} 2659 2660EXPORT_SYMBOL(__tcp_put_md5sig_pool); 2661#endif 2662 2663void tcp_done(struct sock *sk) 2664{ 2665 if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 2666 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS); 2667 2668 tcp_set_state(sk, TCP_CLOSE); 2669 tcp_clear_xmit_timers(sk); 2670 2671 sk->sk_shutdown = SHUTDOWN_MASK; 2672 2673 if (!sock_flag(sk, SOCK_DEAD)) 2674 sk->sk_state_change(sk); 2675 else 2676 inet_csk_destroy_sock(sk); 2677} 2678EXPORT_SYMBOL_GPL(tcp_done); 2679 2680extern struct tcp_congestion_ops tcp_reno; 2681 2682static __initdata unsigned long thash_entries; 2683static int __init set_thash_entries(char *str) 2684{ 2685 if (!str) 2686 return 0; 2687 thash_entries = simple_strtoul(str, &str, 0); 2688 return 1; 2689} 2690__setup("thash_entries=", set_thash_entries); 2691 2692void __init tcp_init(void) 2693{ 2694 struct sk_buff *skb = NULL; 2695 unsigned long nr_pages, limit; 2696 int order, i, max_share; 2697 2698 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb)); 2699 2700 tcp_hashinfo.bind_bucket_cachep = 2701 kmem_cache_create("tcp_bind_bucket", 2702 sizeof(struct inet_bind_bucket), 0, 2703 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 2704 2705 /* Size and allocate the main established and bind bucket 2706 * hash tables. 2707 * 2708 * The methodology is similar to that of the buffer cache. 2709 */ 2710 tcp_hashinfo.ehash = 2711 alloc_large_system_hash("TCP established", 2712 sizeof(struct inet_ehash_bucket), 2713 thash_entries, 2714 (num_physpages >= 128 * 1024) ? 2715 13 : 15, 2716 0, 2717 &tcp_hashinfo.ehash_size, 2718 NULL, 2719 thash_entries ? 0 : 512 * 1024); 2720 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size; 2721 for (i = 0; i < tcp_hashinfo.ehash_size; i++) { 2722 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain); 2723 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain); 2724 } 2725 if (inet_ehash_locks_alloc(&tcp_hashinfo)) 2726 panic("TCP: failed to alloc ehash_locks"); 2727 tcp_hashinfo.bhash = 2728 alloc_large_system_hash("TCP bind", 2729 sizeof(struct inet_bind_hashbucket), 2730 tcp_hashinfo.ehash_size, 2731 (num_physpages >= 128 * 1024) ? 2732 13 : 15, 2733 0, 2734 &tcp_hashinfo.bhash_size, 2735 NULL, 2736 64 * 1024); 2737 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size; 2738 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 2739 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 2740 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 2741 } 2742 2743 /* Try to be a bit smarter and adjust defaults depending 2744 * on available memory. 2745 */ 2746 for (order = 0; ((1 << order) << PAGE_SHIFT) < 2747 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket)); 2748 order++) 2749 ; 2750 if (order >= 4) { 2751 tcp_death_row.sysctl_max_tw_buckets = 180000; 2752 sysctl_tcp_max_orphans = 4096 << (order - 4); 2753 sysctl_max_syn_backlog = 1024; 2754 } else if (order < 3) { 2755 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order); 2756 sysctl_tcp_max_orphans >>= (3 - order); 2757 sysctl_max_syn_backlog = 128; 2758 } 2759 2760 /* Set the pressure threshold to be a fraction of global memory that 2761 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of 2762 * memory, with a floor of 128 pages. 2763 */ 2764 nr_pages = totalram_pages - totalhigh_pages; 2765 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); 2766 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); 2767 limit = max(limit, 128UL); 2768 sysctl_tcp_mem[0] = limit / 4 * 3; 2769 sysctl_tcp_mem[1] = limit; 2770 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; 2771 2772 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 2773 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7); 2774 max_share = min(4UL*1024*1024, limit); 2775 2776 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM; 2777 sysctl_tcp_wmem[1] = 16*1024; 2778 sysctl_tcp_wmem[2] = max(64*1024, max_share); 2779 2780 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; 2781 sysctl_tcp_rmem[1] = 87380; 2782 sysctl_tcp_rmem[2] = max(87380, max_share); 2783 2784 printk(KERN_INFO "TCP: Hash tables configured " 2785 "(established %d bind %d)\n", 2786 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size); 2787 2788 tcp_register_congestion_control(&tcp_reno); 2789} 2790 2791EXPORT_SYMBOL(tcp_close); 2792EXPORT_SYMBOL(tcp_disconnect); 2793EXPORT_SYMBOL(tcp_getsockopt); 2794EXPORT_SYMBOL(tcp_ioctl); 2795EXPORT_SYMBOL(tcp_poll); 2796EXPORT_SYMBOL(tcp_read_sock); 2797EXPORT_SYMBOL(tcp_recvmsg); 2798EXPORT_SYMBOL(tcp_sendmsg); 2799EXPORT_SYMBOL(tcp_splice_read); 2800EXPORT_SYMBOL(tcp_sendpage); 2801EXPORT_SYMBOL(tcp_setsockopt); 2802EXPORT_SYMBOL(tcp_shutdown); 2803