tcp.c revision 7945cc6464a4db0caf6dfacdfe05806051c4cb7b
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 280struct percpu_counter tcp_orphan_count; 281EXPORT_SYMBOL_GPL(tcp_orphan_count); 282 283int sysctl_tcp_mem[3] __read_mostly; 284int sysctl_tcp_wmem[3] __read_mostly; 285int sysctl_tcp_rmem[3] __read_mostly; 286 287EXPORT_SYMBOL(sysctl_tcp_mem); 288EXPORT_SYMBOL(sysctl_tcp_rmem); 289EXPORT_SYMBOL(sysctl_tcp_wmem); 290 291atomic_t tcp_memory_allocated; /* Current allocated memory. */ 292EXPORT_SYMBOL(tcp_memory_allocated); 293 294/* 295 * Current number of TCP sockets. 296 */ 297struct percpu_counter tcp_sockets_allocated; 298EXPORT_SYMBOL(tcp_sockets_allocated); 299 300/* 301 * TCP splice context 302 */ 303struct tcp_splice_state { 304 struct pipe_inode_info *pipe; 305 size_t len; 306 unsigned int flags; 307}; 308 309/* 310 * Pressure flag: try to collapse. 311 * Technical note: it is used by multiple contexts non atomically. 312 * All the __sk_mem_schedule() is of this nature: accounting 313 * is strict, actions are advisory and have some latency. 314 */ 315int tcp_memory_pressure __read_mostly; 316 317EXPORT_SYMBOL(tcp_memory_pressure); 318 319void tcp_enter_memory_pressure(struct sock *sk) 320{ 321 if (!tcp_memory_pressure) { 322 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES); 323 tcp_memory_pressure = 1; 324 } 325} 326 327EXPORT_SYMBOL(tcp_enter_memory_pressure); 328 329/* 330 * Wait for a TCP event. 331 * 332 * Note that we don't need to lock the socket, as the upper poll layers 333 * take care of normal races (between the test and the event) and we don't 334 * go look at any of the socket buffers directly. 335 */ 336unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 337{ 338 unsigned int mask; 339 struct sock *sk = sock->sk; 340 struct tcp_sock *tp = tcp_sk(sk); 341 342 poll_wait(file, sk->sk_sleep, wait); 343 if (sk->sk_state == TCP_LISTEN) 344 return inet_csk_listen_poll(sk); 345 346 /* Socket is not locked. We are protected from async events 347 * by poll logic and correct handling of state changes 348 * made by other threads is impossible in any case. 349 */ 350 351 mask = 0; 352 if (sk->sk_err) 353 mask = POLLERR; 354 355 /* 356 * POLLHUP is certainly not done right. But poll() doesn't 357 * have a notion of HUP in just one direction, and for a 358 * socket the read side is more interesting. 359 * 360 * Some poll() documentation says that POLLHUP is incompatible 361 * with the POLLOUT/POLLWR flags, so somebody should check this 362 * all. But careful, it tends to be safer to return too many 363 * bits than too few, and you can easily break real applications 364 * if you don't tell them that something has hung up! 365 * 366 * Check-me. 367 * 368 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 369 * our fs/select.c). It means that after we received EOF, 370 * poll always returns immediately, making impossible poll() on write() 371 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 372 * if and only if shutdown has been made in both directions. 373 * Actually, it is interesting to look how Solaris and DUX 374 * solve this dilemma. I would prefer, if POLLHUP were maskable, 375 * then we could set it on SND_SHUTDOWN. BTW examples given 376 * in Stevens' books assume exactly this behaviour, it explains 377 * why POLLHUP is incompatible with POLLOUT. --ANK 378 * 379 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 380 * blocking on fresh not-connected or disconnected socket. --ANK 381 */ 382 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 383 mask |= POLLHUP; 384 if (sk->sk_shutdown & RCV_SHUTDOWN) 385 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 386 387 /* Connected? */ 388 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) { 389 int target = sock_rcvlowat(sk, 0, INT_MAX); 390 391 if (tp->urg_seq == tp->copied_seq && 392 !sock_flag(sk, SOCK_URGINLINE) && 393 tp->urg_data) 394 target--; 395 396 /* Potential race condition. If read of tp below will 397 * escape above sk->sk_state, we can be illegally awaken 398 * in SYN_* states. */ 399 if (tp->rcv_nxt - tp->copied_seq >= target) 400 mask |= POLLIN | POLLRDNORM; 401 402 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 403 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) { 404 mask |= POLLOUT | POLLWRNORM; 405 } else { /* send SIGIO later */ 406 set_bit(SOCK_ASYNC_NOSPACE, 407 &sk->sk_socket->flags); 408 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 409 410 /* Race breaker. If space is freed after 411 * wspace test but before the flags are set, 412 * IO signal will be lost. 413 */ 414 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) 415 mask |= POLLOUT | POLLWRNORM; 416 } 417 } 418 419 if (tp->urg_data & TCP_URG_VALID) 420 mask |= POLLPRI; 421 } 422 return mask; 423} 424 425int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 426{ 427 struct tcp_sock *tp = tcp_sk(sk); 428 int answ; 429 430 switch (cmd) { 431 case SIOCINQ: 432 if (sk->sk_state == TCP_LISTEN) 433 return -EINVAL; 434 435 lock_sock(sk); 436 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 437 answ = 0; 438 else if (sock_flag(sk, SOCK_URGINLINE) || 439 !tp->urg_data || 440 before(tp->urg_seq, tp->copied_seq) || 441 !before(tp->urg_seq, tp->rcv_nxt)) { 442 answ = tp->rcv_nxt - tp->copied_seq; 443 444 /* Subtract 1, if FIN is in queue. */ 445 if (answ && !skb_queue_empty(&sk->sk_receive_queue)) 446 answ -= 447 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin; 448 } else 449 answ = tp->urg_seq - tp->copied_seq; 450 release_sock(sk); 451 break; 452 case SIOCATMARK: 453 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 454 break; 455 case SIOCOUTQ: 456 if (sk->sk_state == TCP_LISTEN) 457 return -EINVAL; 458 459 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 460 answ = 0; 461 else 462 answ = tp->write_seq - tp->snd_una; 463 break; 464 default: 465 return -ENOIOCTLCMD; 466 } 467 468 return put_user(answ, (int __user *)arg); 469} 470 471static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 472{ 473 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH; 474 tp->pushed_seq = tp->write_seq; 475} 476 477static inline int forced_push(struct tcp_sock *tp) 478{ 479 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 480} 481 482static inline void skb_entail(struct sock *sk, struct sk_buff *skb) 483{ 484 struct tcp_sock *tp = tcp_sk(sk); 485 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 486 487 skb->csum = 0; 488 tcb->seq = tcb->end_seq = tp->write_seq; 489 tcb->flags = TCPCB_FLAG_ACK; 490 tcb->sacked = 0; 491 skb_header_release(skb); 492 tcp_add_write_queue_tail(sk, skb); 493 sk->sk_wmem_queued += skb->truesize; 494 sk_mem_charge(sk, skb->truesize); 495 if (tp->nonagle & TCP_NAGLE_PUSH) 496 tp->nonagle &= ~TCP_NAGLE_PUSH; 497} 498 499static inline void tcp_mark_urg(struct tcp_sock *tp, int flags, 500 struct sk_buff *skb) 501{ 502 if (flags & MSG_OOB) 503 tp->snd_up = tp->write_seq; 504} 505 506static inline void tcp_push(struct sock *sk, int flags, int mss_now, 507 int nonagle) 508{ 509 struct tcp_sock *tp = tcp_sk(sk); 510 511 if (tcp_send_head(sk)) { 512 struct sk_buff *skb = tcp_write_queue_tail(sk); 513 if (!(flags & MSG_MORE) || forced_push(tp)) 514 tcp_mark_push(tp, skb); 515 tcp_mark_urg(tp, flags, skb); 516 __tcp_push_pending_frames(sk, mss_now, 517 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle); 518 } 519} 520 521static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, 522 unsigned int offset, size_t len) 523{ 524 struct tcp_splice_state *tss = rd_desc->arg.data; 525 526 return skb_splice_bits(skb, offset, tss->pipe, tss->len, tss->flags); 527} 528 529static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss) 530{ 531 /* Store TCP splice context information in read_descriptor_t. */ 532 read_descriptor_t rd_desc = { 533 .arg.data = tss, 534 }; 535 536 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv); 537} 538 539/** 540 * tcp_splice_read - splice data from TCP socket to a pipe 541 * @sock: socket to splice from 542 * @ppos: position (not valid) 543 * @pipe: pipe to splice to 544 * @len: number of bytes to splice 545 * @flags: splice modifier flags 546 * 547 * Description: 548 * Will read pages from given socket and fill them into a pipe. 549 * 550 **/ 551ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, 552 struct pipe_inode_info *pipe, size_t len, 553 unsigned int flags) 554{ 555 struct sock *sk = sock->sk; 556 struct tcp_splice_state tss = { 557 .pipe = pipe, 558 .len = len, 559 .flags = flags, 560 }; 561 long timeo; 562 ssize_t spliced; 563 int ret; 564 565 /* 566 * We can't seek on a socket input 567 */ 568 if (unlikely(*ppos)) 569 return -ESPIPE; 570 571 ret = spliced = 0; 572 573 lock_sock(sk); 574 575 timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK); 576 while (tss.len) { 577 ret = __tcp_splice_read(sk, &tss); 578 if (ret < 0) 579 break; 580 else if (!ret) { 581 if (spliced) 582 break; 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 WARN_ON(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_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 WARN_ON(!(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 break; 1377 } else { 1378 if (sock_flag(sk, SOCK_DONE)) 1379 break; 1380 1381 if (sk->sk_err) { 1382 copied = sock_error(sk); 1383 break; 1384 } 1385 1386 if (sk->sk_shutdown & RCV_SHUTDOWN) 1387 break; 1388 1389 if (sk->sk_state == TCP_CLOSE) { 1390 if (!sock_flag(sk, SOCK_DONE)) { 1391 /* This occurs when user tries to read 1392 * from never connected socket. 1393 */ 1394 copied = -ENOTCONN; 1395 break; 1396 } 1397 break; 1398 } 1399 1400 if (!timeo) { 1401 copied = -EAGAIN; 1402 break; 1403 } 1404 1405 if (signal_pending(current)) { 1406 copied = sock_intr_errno(timeo); 1407 break; 1408 } 1409 } 1410 1411 tcp_cleanup_rbuf(sk, copied); 1412 1413 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1414 /* Install new reader */ 1415 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1416 user_recv = current; 1417 tp->ucopy.task = user_recv; 1418 tp->ucopy.iov = msg->msg_iov; 1419 } 1420 1421 tp->ucopy.len = len; 1422 1423 WARN_ON(tp->copied_seq != tp->rcv_nxt && 1424 !(flags & (MSG_PEEK | MSG_TRUNC))); 1425 1426 /* Ugly... If prequeue is not empty, we have to 1427 * process it before releasing socket, otherwise 1428 * order will be broken at second iteration. 1429 * More elegant solution is required!!! 1430 * 1431 * Look: we have the following (pseudo)queues: 1432 * 1433 * 1. packets in flight 1434 * 2. backlog 1435 * 3. prequeue 1436 * 4. receive_queue 1437 * 1438 * Each queue can be processed only if the next ones 1439 * are empty. At this point we have empty receive_queue. 1440 * But prequeue _can_ be not empty after 2nd iteration, 1441 * when we jumped to start of loop because backlog 1442 * processing added something to receive_queue. 1443 * We cannot release_sock(), because backlog contains 1444 * packets arrived _after_ prequeued ones. 1445 * 1446 * Shortly, algorithm is clear --- to process all 1447 * the queues in order. We could make it more directly, 1448 * requeueing packets from backlog to prequeue, if 1449 * is not empty. It is more elegant, but eats cycles, 1450 * unfortunately. 1451 */ 1452 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1453 goto do_prequeue; 1454 1455 /* __ Set realtime policy in scheduler __ */ 1456 } 1457 1458 if (copied >= target) { 1459 /* Do not sleep, just process backlog. */ 1460 release_sock(sk); 1461 lock_sock(sk); 1462 } else 1463 sk_wait_data(sk, &timeo); 1464 1465#ifdef CONFIG_NET_DMA 1466 tp->ucopy.wakeup = 0; 1467#endif 1468 1469 if (user_recv) { 1470 int chunk; 1471 1472 /* __ Restore normal policy in scheduler __ */ 1473 1474 if ((chunk = len - tp->ucopy.len) != 0) { 1475 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1476 len -= chunk; 1477 copied += chunk; 1478 } 1479 1480 if (tp->rcv_nxt == tp->copied_seq && 1481 !skb_queue_empty(&tp->ucopy.prequeue)) { 1482do_prequeue: 1483 tcp_prequeue_process(sk); 1484 1485 if ((chunk = len - tp->ucopy.len) != 0) { 1486 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1487 len -= chunk; 1488 copied += chunk; 1489 } 1490 } 1491 } 1492 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) { 1493 if (net_ratelimit()) 1494 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n", 1495 current->comm, task_pid_nr(current)); 1496 peek_seq = tp->copied_seq; 1497 } 1498 continue; 1499 1500 found_ok_skb: 1501 /* Ok so how much can we use? */ 1502 used = skb->len - offset; 1503 if (len < used) 1504 used = len; 1505 1506 /* Do we have urgent data here? */ 1507 if (tp->urg_data) { 1508 u32 urg_offset = tp->urg_seq - *seq; 1509 if (urg_offset < used) { 1510 if (!urg_offset) { 1511 if (!sock_flag(sk, SOCK_URGINLINE)) { 1512 ++*seq; 1513 offset++; 1514 used--; 1515 if (!used) 1516 goto skip_copy; 1517 } 1518 } else 1519 used = urg_offset; 1520 } 1521 } 1522 1523 if (!(flags & MSG_TRUNC)) { 1524#ifdef CONFIG_NET_DMA 1525 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) 1526 tp->ucopy.dma_chan = get_softnet_dma(); 1527 1528 if (tp->ucopy.dma_chan) { 1529 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec( 1530 tp->ucopy.dma_chan, skb, offset, 1531 msg->msg_iov, used, 1532 tp->ucopy.pinned_list); 1533 1534 if (tp->ucopy.dma_cookie < 0) { 1535 1536 printk(KERN_ALERT "dma_cookie < 0\n"); 1537 1538 /* Exception. Bailout! */ 1539 if (!copied) 1540 copied = -EFAULT; 1541 break; 1542 } 1543 if ((offset + used) == skb->len) 1544 copied_early = 1; 1545 1546 } else 1547#endif 1548 { 1549 err = skb_copy_datagram_iovec(skb, offset, 1550 msg->msg_iov, used); 1551 if (err) { 1552 /* Exception. Bailout! */ 1553 if (!copied) 1554 copied = -EFAULT; 1555 break; 1556 } 1557 } 1558 } 1559 1560 *seq += used; 1561 copied += used; 1562 len -= used; 1563 1564 tcp_rcv_space_adjust(sk); 1565 1566skip_copy: 1567 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1568 tp->urg_data = 0; 1569 tcp_fast_path_check(sk); 1570 } 1571 if (used + offset < skb->len) 1572 continue; 1573 1574 if (tcp_hdr(skb)->fin) 1575 goto found_fin_ok; 1576 if (!(flags & MSG_PEEK)) { 1577 sk_eat_skb(sk, skb, copied_early); 1578 copied_early = 0; 1579 } 1580 continue; 1581 1582 found_fin_ok: 1583 /* Process the FIN. */ 1584 ++*seq; 1585 if (!(flags & MSG_PEEK)) { 1586 sk_eat_skb(sk, skb, copied_early); 1587 copied_early = 0; 1588 } 1589 break; 1590 } while (len > 0); 1591 1592 if (user_recv) { 1593 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1594 int chunk; 1595 1596 tp->ucopy.len = copied > 0 ? len : 0; 1597 1598 tcp_prequeue_process(sk); 1599 1600 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1601 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1602 len -= chunk; 1603 copied += chunk; 1604 } 1605 } 1606 1607 tp->ucopy.task = NULL; 1608 tp->ucopy.len = 0; 1609 } 1610 1611#ifdef CONFIG_NET_DMA 1612 if (tp->ucopy.dma_chan) { 1613 dma_cookie_t done, used; 1614 1615 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1616 1617 while (dma_async_memcpy_complete(tp->ucopy.dma_chan, 1618 tp->ucopy.dma_cookie, &done, 1619 &used) == DMA_IN_PROGRESS) { 1620 /* do partial cleanup of sk_async_wait_queue */ 1621 while ((skb = skb_peek(&sk->sk_async_wait_queue)) && 1622 (dma_async_is_complete(skb->dma_cookie, done, 1623 used) == DMA_SUCCESS)) { 1624 __skb_dequeue(&sk->sk_async_wait_queue); 1625 kfree_skb(skb); 1626 } 1627 } 1628 1629 /* Safe to free early-copied skbs now */ 1630 __skb_queue_purge(&sk->sk_async_wait_queue); 1631 dma_chan_put(tp->ucopy.dma_chan); 1632 tp->ucopy.dma_chan = NULL; 1633 } 1634 if (tp->ucopy.pinned_list) { 1635 dma_unpin_iovec_pages(tp->ucopy.pinned_list); 1636 tp->ucopy.pinned_list = NULL; 1637 } 1638#endif 1639 1640 /* According to UNIX98, msg_name/msg_namelen are ignored 1641 * on connected socket. I was just happy when found this 8) --ANK 1642 */ 1643 1644 /* Clean up data we have read: This will do ACK frames. */ 1645 tcp_cleanup_rbuf(sk, copied); 1646 1647 TCP_CHECK_TIMER(sk); 1648 release_sock(sk); 1649 return copied; 1650 1651out: 1652 TCP_CHECK_TIMER(sk); 1653 release_sock(sk); 1654 return err; 1655 1656recv_urg: 1657 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len); 1658 goto out; 1659} 1660 1661void tcp_set_state(struct sock *sk, int state) 1662{ 1663 int oldstate = sk->sk_state; 1664 1665 switch (state) { 1666 case TCP_ESTABLISHED: 1667 if (oldstate != TCP_ESTABLISHED) 1668 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1669 break; 1670 1671 case TCP_CLOSE: 1672 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 1673 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS); 1674 1675 sk->sk_prot->unhash(sk); 1676 if (inet_csk(sk)->icsk_bind_hash && 1677 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 1678 inet_put_port(sk); 1679 /* fall through */ 1680 default: 1681 if (oldstate == TCP_ESTABLISHED) 1682 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1683 } 1684 1685 /* Change state AFTER socket is unhashed to avoid closed 1686 * socket sitting in hash tables. 1687 */ 1688 sk->sk_state = state; 1689 1690#ifdef STATE_TRACE 1691 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]); 1692#endif 1693} 1694EXPORT_SYMBOL_GPL(tcp_set_state); 1695 1696/* 1697 * State processing on a close. This implements the state shift for 1698 * sending our FIN frame. Note that we only send a FIN for some 1699 * states. A shutdown() may have already sent the FIN, or we may be 1700 * closed. 1701 */ 1702 1703static const unsigned char new_state[16] = { 1704 /* current state: new state: action: */ 1705 /* (Invalid) */ TCP_CLOSE, 1706 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1707 /* TCP_SYN_SENT */ TCP_CLOSE, 1708 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1709 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, 1710 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, 1711 /* TCP_TIME_WAIT */ TCP_CLOSE, 1712 /* TCP_CLOSE */ TCP_CLOSE, 1713 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, 1714 /* TCP_LAST_ACK */ TCP_LAST_ACK, 1715 /* TCP_LISTEN */ TCP_CLOSE, 1716 /* TCP_CLOSING */ TCP_CLOSING, 1717}; 1718 1719static int tcp_close_state(struct sock *sk) 1720{ 1721 int next = (int)new_state[sk->sk_state]; 1722 int ns = next & TCP_STATE_MASK; 1723 1724 tcp_set_state(sk, ns); 1725 1726 return next & TCP_ACTION_FIN; 1727} 1728 1729/* 1730 * Shutdown the sending side of a connection. Much like close except 1731 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD). 1732 */ 1733 1734void tcp_shutdown(struct sock *sk, int how) 1735{ 1736 /* We need to grab some memory, and put together a FIN, 1737 * and then put it into the queue to be sent. 1738 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 1739 */ 1740 if (!(how & SEND_SHUTDOWN)) 1741 return; 1742 1743 /* If we've already sent a FIN, or it's a closed state, skip this. */ 1744 if ((1 << sk->sk_state) & 1745 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 1746 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 1747 /* Clear out any half completed packets. FIN if needed. */ 1748 if (tcp_close_state(sk)) 1749 tcp_send_fin(sk); 1750 } 1751} 1752 1753void tcp_close(struct sock *sk, long timeout) 1754{ 1755 struct sk_buff *skb; 1756 int data_was_unread = 0; 1757 int state; 1758 1759 lock_sock(sk); 1760 sk->sk_shutdown = SHUTDOWN_MASK; 1761 1762 if (sk->sk_state == TCP_LISTEN) { 1763 tcp_set_state(sk, TCP_CLOSE); 1764 1765 /* Special case. */ 1766 inet_csk_listen_stop(sk); 1767 1768 goto adjudge_to_death; 1769 } 1770 1771 /* We need to flush the recv. buffs. We do this only on the 1772 * descriptor close, not protocol-sourced closes, because the 1773 * reader process may not have drained the data yet! 1774 */ 1775 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 1776 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq - 1777 tcp_hdr(skb)->fin; 1778 data_was_unread += len; 1779 __kfree_skb(skb); 1780 } 1781 1782 sk_mem_reclaim(sk); 1783 1784 /* As outlined in RFC 2525, section 2.17, we send a RST here because 1785 * data was lost. To witness the awful effects of the old behavior of 1786 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk 1787 * GET in an FTP client, suspend the process, wait for the client to 1788 * advertise a zero window, then kill -9 the FTP client, wheee... 1789 * Note: timeout is always zero in such a case. 1790 */ 1791 if (data_was_unread) { 1792 /* Unread data was tossed, zap the connection. */ 1793 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE); 1794 tcp_set_state(sk, TCP_CLOSE); 1795 tcp_send_active_reset(sk, GFP_KERNEL); 1796 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 1797 /* Check zero linger _after_ checking for unread data. */ 1798 sk->sk_prot->disconnect(sk, 0); 1799 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA); 1800 } else if (tcp_close_state(sk)) { 1801 /* We FIN if the application ate all the data before 1802 * zapping the connection. 1803 */ 1804 1805 /* RED-PEN. Formally speaking, we have broken TCP state 1806 * machine. State transitions: 1807 * 1808 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 1809 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 1810 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 1811 * 1812 * are legal only when FIN has been sent (i.e. in window), 1813 * rather than queued out of window. Purists blame. 1814 * 1815 * F.e. "RFC state" is ESTABLISHED, 1816 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 1817 * 1818 * The visible declinations are that sometimes 1819 * we enter time-wait state, when it is not required really 1820 * (harmless), do not send active resets, when they are 1821 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 1822 * they look as CLOSING or LAST_ACK for Linux) 1823 * Probably, I missed some more holelets. 1824 * --ANK 1825 */ 1826 tcp_send_fin(sk); 1827 } 1828 1829 sk_stream_wait_close(sk, timeout); 1830 1831adjudge_to_death: 1832 state = sk->sk_state; 1833 sock_hold(sk); 1834 sock_orphan(sk); 1835 1836 /* It is the last release_sock in its life. It will remove backlog. */ 1837 release_sock(sk); 1838 1839 1840 /* Now socket is owned by kernel and we acquire BH lock 1841 to finish close. No need to check for user refs. 1842 */ 1843 local_bh_disable(); 1844 bh_lock_sock(sk); 1845 WARN_ON(sock_owned_by_user(sk)); 1846 1847 percpu_counter_inc(sk->sk_prot->orphan_count); 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 int orphan_count = percpu_counter_read_positive( 1888 sk->sk_prot->orphan_count); 1889 1890 sk_mem_reclaim(sk); 1891 if (tcp_too_many_orphans(sk, orphan_count)) { 1892 if (net_ratelimit()) 1893 printk(KERN_INFO "TCP: too many of orphaned " 1894 "sockets\n"); 1895 tcp_set_state(sk, TCP_CLOSE); 1896 tcp_send_active_reset(sk, GFP_ATOMIC); 1897 NET_INC_STATS_BH(sock_net(sk), 1898 LINUX_MIB_TCPABORTONMEMORY); 1899 } 1900 } 1901 1902 if (sk->sk_state == TCP_CLOSE) 1903 inet_csk_destroy_sock(sk); 1904 /* Otherwise, socket is reprieved until protocol close. */ 1905 1906out: 1907 bh_unlock_sock(sk); 1908 local_bh_enable(); 1909 sock_put(sk); 1910} 1911 1912/* These states need RST on ABORT according to RFC793 */ 1913 1914static inline int tcp_need_reset(int state) 1915{ 1916 return (1 << state) & 1917 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 1918 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 1919} 1920 1921int tcp_disconnect(struct sock *sk, int flags) 1922{ 1923 struct inet_sock *inet = inet_sk(sk); 1924 struct inet_connection_sock *icsk = inet_csk(sk); 1925 struct tcp_sock *tp = tcp_sk(sk); 1926 int err = 0; 1927 int old_state = sk->sk_state; 1928 1929 if (old_state != TCP_CLOSE) 1930 tcp_set_state(sk, TCP_CLOSE); 1931 1932 /* ABORT function of RFC793 */ 1933 if (old_state == TCP_LISTEN) { 1934 inet_csk_listen_stop(sk); 1935 } else if (tcp_need_reset(old_state) || 1936 (tp->snd_nxt != tp->write_seq && 1937 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 1938 /* The last check adjusts for discrepancy of Linux wrt. RFC 1939 * states 1940 */ 1941 tcp_send_active_reset(sk, gfp_any()); 1942 sk->sk_err = ECONNRESET; 1943 } else if (old_state == TCP_SYN_SENT) 1944 sk->sk_err = ECONNRESET; 1945 1946 tcp_clear_xmit_timers(sk); 1947 __skb_queue_purge(&sk->sk_receive_queue); 1948 tcp_write_queue_purge(sk); 1949 __skb_queue_purge(&tp->out_of_order_queue); 1950#ifdef CONFIG_NET_DMA 1951 __skb_queue_purge(&sk->sk_async_wait_queue); 1952#endif 1953 1954 inet->dport = 0; 1955 1956 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 1957 inet_reset_saddr(sk); 1958 1959 sk->sk_shutdown = 0; 1960 sock_reset_flag(sk, SOCK_DONE); 1961 tp->srtt = 0; 1962 if ((tp->write_seq += tp->max_window + 2) == 0) 1963 tp->write_seq = 1; 1964 icsk->icsk_backoff = 0; 1965 tp->snd_cwnd = 2; 1966 icsk->icsk_probes_out = 0; 1967 tp->packets_out = 0; 1968 tp->snd_ssthresh = 0x7fffffff; 1969 tp->snd_cwnd_cnt = 0; 1970 tp->bytes_acked = 0; 1971 tcp_set_ca_state(sk, TCP_CA_Open); 1972 tcp_clear_retrans(tp); 1973 inet_csk_delack_init(sk); 1974 tcp_init_send_head(sk); 1975 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); 1976 __sk_dst_reset(sk); 1977 1978 WARN_ON(inet->num && !icsk->icsk_bind_hash); 1979 1980 sk->sk_error_report(sk); 1981 return err; 1982} 1983 1984/* 1985 * Socket option code for TCP. 1986 */ 1987static int do_tcp_setsockopt(struct sock *sk, int level, 1988 int optname, char __user *optval, int optlen) 1989{ 1990 struct tcp_sock *tp = tcp_sk(sk); 1991 struct inet_connection_sock *icsk = inet_csk(sk); 1992 int val; 1993 int err = 0; 1994 1995 /* This is a string value all the others are int's */ 1996 if (optname == TCP_CONGESTION) { 1997 char name[TCP_CA_NAME_MAX]; 1998 1999 if (optlen < 1) 2000 return -EINVAL; 2001 2002 val = strncpy_from_user(name, optval, 2003 min(TCP_CA_NAME_MAX-1, optlen)); 2004 if (val < 0) 2005 return -EFAULT; 2006 name[val] = 0; 2007 2008 lock_sock(sk); 2009 err = tcp_set_congestion_control(sk, name); 2010 release_sock(sk); 2011 return err; 2012 } 2013 2014 if (optlen < sizeof(int)) 2015 return -EINVAL; 2016 2017 if (get_user(val, (int __user *)optval)) 2018 return -EFAULT; 2019 2020 lock_sock(sk); 2021 2022 switch (optname) { 2023 case TCP_MAXSEG: 2024 /* Values greater than interface MTU won't take effect. However 2025 * at the point when this call is done we typically don't yet 2026 * know which interface is going to be used */ 2027 if (val < 8 || val > MAX_TCP_WINDOW) { 2028 err = -EINVAL; 2029 break; 2030 } 2031 tp->rx_opt.user_mss = val; 2032 break; 2033 2034 case TCP_NODELAY: 2035 if (val) { 2036 /* TCP_NODELAY is weaker than TCP_CORK, so that 2037 * this option on corked socket is remembered, but 2038 * it is not activated until cork is cleared. 2039 * 2040 * However, when TCP_NODELAY is set we make 2041 * an explicit push, which overrides even TCP_CORK 2042 * for currently queued segments. 2043 */ 2044 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 2045 tcp_push_pending_frames(sk); 2046 } else { 2047 tp->nonagle &= ~TCP_NAGLE_OFF; 2048 } 2049 break; 2050 2051 case TCP_CORK: 2052 /* When set indicates to always queue non-full frames. 2053 * Later the user clears this option and we transmit 2054 * any pending partial frames in the queue. This is 2055 * meant to be used alongside sendfile() to get properly 2056 * filled frames when the user (for example) must write 2057 * out headers with a write() call first and then use 2058 * sendfile to send out the data parts. 2059 * 2060 * TCP_CORK can be set together with TCP_NODELAY and it is 2061 * stronger than TCP_NODELAY. 2062 */ 2063 if (val) { 2064 tp->nonagle |= TCP_NAGLE_CORK; 2065 } else { 2066 tp->nonagle &= ~TCP_NAGLE_CORK; 2067 if (tp->nonagle&TCP_NAGLE_OFF) 2068 tp->nonagle |= TCP_NAGLE_PUSH; 2069 tcp_push_pending_frames(sk); 2070 } 2071 break; 2072 2073 case TCP_KEEPIDLE: 2074 if (val < 1 || val > MAX_TCP_KEEPIDLE) 2075 err = -EINVAL; 2076 else { 2077 tp->keepalive_time = val * HZ; 2078 if (sock_flag(sk, SOCK_KEEPOPEN) && 2079 !((1 << sk->sk_state) & 2080 (TCPF_CLOSE | TCPF_LISTEN))) { 2081 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp; 2082 if (tp->keepalive_time > elapsed) 2083 elapsed = tp->keepalive_time - elapsed; 2084 else 2085 elapsed = 0; 2086 inet_csk_reset_keepalive_timer(sk, elapsed); 2087 } 2088 } 2089 break; 2090 case TCP_KEEPINTVL: 2091 if (val < 1 || val > MAX_TCP_KEEPINTVL) 2092 err = -EINVAL; 2093 else 2094 tp->keepalive_intvl = val * HZ; 2095 break; 2096 case TCP_KEEPCNT: 2097 if (val < 1 || val > MAX_TCP_KEEPCNT) 2098 err = -EINVAL; 2099 else 2100 tp->keepalive_probes = val; 2101 break; 2102 case TCP_SYNCNT: 2103 if (val < 1 || val > MAX_TCP_SYNCNT) 2104 err = -EINVAL; 2105 else 2106 icsk->icsk_syn_retries = val; 2107 break; 2108 2109 case TCP_LINGER2: 2110 if (val < 0) 2111 tp->linger2 = -1; 2112 else if (val > sysctl_tcp_fin_timeout / HZ) 2113 tp->linger2 = 0; 2114 else 2115 tp->linger2 = val * HZ; 2116 break; 2117 2118 case TCP_DEFER_ACCEPT: 2119 icsk->icsk_accept_queue.rskq_defer_accept = 0; 2120 if (val > 0) { 2121 /* Translate value in seconds to number of 2122 * retransmits */ 2123 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 && 2124 val > ((TCP_TIMEOUT_INIT / HZ) << 2125 icsk->icsk_accept_queue.rskq_defer_accept)) 2126 icsk->icsk_accept_queue.rskq_defer_accept++; 2127 icsk->icsk_accept_queue.rskq_defer_accept++; 2128 } 2129 break; 2130 2131 case TCP_WINDOW_CLAMP: 2132 if (!val) { 2133 if (sk->sk_state != TCP_CLOSE) { 2134 err = -EINVAL; 2135 break; 2136 } 2137 tp->window_clamp = 0; 2138 } else 2139 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 2140 SOCK_MIN_RCVBUF / 2 : val; 2141 break; 2142 2143 case TCP_QUICKACK: 2144 if (!val) { 2145 icsk->icsk_ack.pingpong = 1; 2146 } else { 2147 icsk->icsk_ack.pingpong = 0; 2148 if ((1 << sk->sk_state) & 2149 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 2150 inet_csk_ack_scheduled(sk)) { 2151 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 2152 tcp_cleanup_rbuf(sk, 1); 2153 if (!(val & 1)) 2154 icsk->icsk_ack.pingpong = 1; 2155 } 2156 } 2157 break; 2158 2159#ifdef CONFIG_TCP_MD5SIG 2160 case TCP_MD5SIG: 2161 /* Read the IP->Key mappings from userspace */ 2162 err = tp->af_specific->md5_parse(sk, optval, optlen); 2163 break; 2164#endif 2165 2166 default: 2167 err = -ENOPROTOOPT; 2168 break; 2169 } 2170 2171 release_sock(sk); 2172 return err; 2173} 2174 2175int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 2176 int optlen) 2177{ 2178 struct inet_connection_sock *icsk = inet_csk(sk); 2179 2180 if (level != SOL_TCP) 2181 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 2182 optval, optlen); 2183 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2184} 2185 2186#ifdef CONFIG_COMPAT 2187int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 2188 char __user *optval, int optlen) 2189{ 2190 if (level != SOL_TCP) 2191 return inet_csk_compat_setsockopt(sk, level, optname, 2192 optval, optlen); 2193 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2194} 2195 2196EXPORT_SYMBOL(compat_tcp_setsockopt); 2197#endif 2198 2199/* Return information about state of tcp endpoint in API format. */ 2200void tcp_get_info(struct sock *sk, struct tcp_info *info) 2201{ 2202 struct tcp_sock *tp = tcp_sk(sk); 2203 const struct inet_connection_sock *icsk = inet_csk(sk); 2204 u32 now = tcp_time_stamp; 2205 2206 memset(info, 0, sizeof(*info)); 2207 2208 info->tcpi_state = sk->sk_state; 2209 info->tcpi_ca_state = icsk->icsk_ca_state; 2210 info->tcpi_retransmits = icsk->icsk_retransmits; 2211 info->tcpi_probes = icsk->icsk_probes_out; 2212 info->tcpi_backoff = icsk->icsk_backoff; 2213 2214 if (tp->rx_opt.tstamp_ok) 2215 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2216 if (tcp_is_sack(tp)) 2217 info->tcpi_options |= TCPI_OPT_SACK; 2218 if (tp->rx_opt.wscale_ok) { 2219 info->tcpi_options |= TCPI_OPT_WSCALE; 2220 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2221 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2222 } 2223 2224 if (tp->ecn_flags&TCP_ECN_OK) 2225 info->tcpi_options |= TCPI_OPT_ECN; 2226 2227 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2228 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2229 info->tcpi_snd_mss = tp->mss_cache; 2230 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2231 2232 if (sk->sk_state == TCP_LISTEN) { 2233 info->tcpi_unacked = sk->sk_ack_backlog; 2234 info->tcpi_sacked = sk->sk_max_ack_backlog; 2235 } else { 2236 info->tcpi_unacked = tp->packets_out; 2237 info->tcpi_sacked = tp->sacked_out; 2238 } 2239 info->tcpi_lost = tp->lost_out; 2240 info->tcpi_retrans = tp->retrans_out; 2241 info->tcpi_fackets = tp->fackets_out; 2242 2243 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2244 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2245 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2246 2247 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2248 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2249 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3; 2250 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2; 2251 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2252 info->tcpi_snd_cwnd = tp->snd_cwnd; 2253 info->tcpi_advmss = tp->advmss; 2254 info->tcpi_reordering = tp->reordering; 2255 2256 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2257 info->tcpi_rcv_space = tp->rcvq_space.space; 2258 2259 info->tcpi_total_retrans = tp->total_retrans; 2260} 2261 2262EXPORT_SYMBOL_GPL(tcp_get_info); 2263 2264static int do_tcp_getsockopt(struct sock *sk, int level, 2265 int optname, char __user *optval, int __user *optlen) 2266{ 2267 struct inet_connection_sock *icsk = inet_csk(sk); 2268 struct tcp_sock *tp = tcp_sk(sk); 2269 int val, len; 2270 2271 if (get_user(len, optlen)) 2272 return -EFAULT; 2273 2274 len = min_t(unsigned int, len, sizeof(int)); 2275 2276 if (len < 0) 2277 return -EINVAL; 2278 2279 switch (optname) { 2280 case TCP_MAXSEG: 2281 val = tp->mss_cache; 2282 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2283 val = tp->rx_opt.user_mss; 2284 break; 2285 case TCP_NODELAY: 2286 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2287 break; 2288 case TCP_CORK: 2289 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2290 break; 2291 case TCP_KEEPIDLE: 2292 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ; 2293 break; 2294 case TCP_KEEPINTVL: 2295 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ; 2296 break; 2297 case TCP_KEEPCNT: 2298 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes; 2299 break; 2300 case TCP_SYNCNT: 2301 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2302 break; 2303 case TCP_LINGER2: 2304 val = tp->linger2; 2305 if (val >= 0) 2306 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2307 break; 2308 case TCP_DEFER_ACCEPT: 2309 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 : 2310 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1)); 2311 break; 2312 case TCP_WINDOW_CLAMP: 2313 val = tp->window_clamp; 2314 break; 2315 case TCP_INFO: { 2316 struct tcp_info info; 2317 2318 if (get_user(len, optlen)) 2319 return -EFAULT; 2320 2321 tcp_get_info(sk, &info); 2322 2323 len = min_t(unsigned int, len, sizeof(info)); 2324 if (put_user(len, optlen)) 2325 return -EFAULT; 2326 if (copy_to_user(optval, &info, len)) 2327 return -EFAULT; 2328 return 0; 2329 } 2330 case TCP_QUICKACK: 2331 val = !icsk->icsk_ack.pingpong; 2332 break; 2333 2334 case TCP_CONGESTION: 2335 if (get_user(len, optlen)) 2336 return -EFAULT; 2337 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2338 if (put_user(len, optlen)) 2339 return -EFAULT; 2340 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2341 return -EFAULT; 2342 return 0; 2343 default: 2344 return -ENOPROTOOPT; 2345 } 2346 2347 if (put_user(len, optlen)) 2348 return -EFAULT; 2349 if (copy_to_user(optval, &val, len)) 2350 return -EFAULT; 2351 return 0; 2352} 2353 2354int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2355 int __user *optlen) 2356{ 2357 struct inet_connection_sock *icsk = inet_csk(sk); 2358 2359 if (level != SOL_TCP) 2360 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2361 optval, optlen); 2362 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2363} 2364 2365#ifdef CONFIG_COMPAT 2366int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2367 char __user *optval, int __user *optlen) 2368{ 2369 if (level != SOL_TCP) 2370 return inet_csk_compat_getsockopt(sk, level, optname, 2371 optval, optlen); 2372 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2373} 2374 2375EXPORT_SYMBOL(compat_tcp_getsockopt); 2376#endif 2377 2378struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features) 2379{ 2380 struct sk_buff *segs = ERR_PTR(-EINVAL); 2381 struct tcphdr *th; 2382 unsigned thlen; 2383 unsigned int seq; 2384 __be32 delta; 2385 unsigned int oldlen; 2386 unsigned int len; 2387 2388 if (!pskb_may_pull(skb, sizeof(*th))) 2389 goto out; 2390 2391 th = tcp_hdr(skb); 2392 thlen = th->doff * 4; 2393 if (thlen < sizeof(*th)) 2394 goto out; 2395 2396 if (!pskb_may_pull(skb, thlen)) 2397 goto out; 2398 2399 oldlen = (u16)~skb->len; 2400 __skb_pull(skb, thlen); 2401 2402 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 2403 /* Packet is from an untrusted source, reset gso_segs. */ 2404 int type = skb_shinfo(skb)->gso_type; 2405 int mss; 2406 2407 if (unlikely(type & 2408 ~(SKB_GSO_TCPV4 | 2409 SKB_GSO_DODGY | 2410 SKB_GSO_TCP_ECN | 2411 SKB_GSO_TCPV6 | 2412 0) || 2413 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) 2414 goto out; 2415 2416 mss = skb_shinfo(skb)->gso_size; 2417 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); 2418 2419 segs = NULL; 2420 goto out; 2421 } 2422 2423 segs = skb_segment(skb, features); 2424 if (IS_ERR(segs)) 2425 goto out; 2426 2427 len = skb_shinfo(skb)->gso_size; 2428 delta = htonl(oldlen + (thlen + len)); 2429 2430 skb = segs; 2431 th = tcp_hdr(skb); 2432 seq = ntohl(th->seq); 2433 2434 do { 2435 th->fin = th->psh = 0; 2436 2437 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2438 (__force u32)delta)); 2439 if (skb->ip_summed != CHECKSUM_PARTIAL) 2440 th->check = 2441 csum_fold(csum_partial(skb_transport_header(skb), 2442 thlen, skb->csum)); 2443 2444 seq += len; 2445 skb = skb->next; 2446 th = tcp_hdr(skb); 2447 2448 th->seq = htonl(seq); 2449 th->cwr = 0; 2450 } while (skb->next); 2451 2452 delta = htonl(oldlen + (skb->tail - skb->transport_header) + 2453 skb->data_len); 2454 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2455 (__force u32)delta)); 2456 if (skb->ip_summed != CHECKSUM_PARTIAL) 2457 th->check = csum_fold(csum_partial(skb_transport_header(skb), 2458 thlen, skb->csum)); 2459 2460out: 2461 return segs; 2462} 2463EXPORT_SYMBOL(tcp_tso_segment); 2464 2465struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) 2466{ 2467 struct sk_buff **pp = NULL; 2468 struct sk_buff *p; 2469 struct tcphdr *th; 2470 struct tcphdr *th2; 2471 unsigned int thlen; 2472 unsigned int flags; 2473 unsigned int total; 2474 unsigned int mss = 1; 2475 int flush = 1; 2476 2477 if (!pskb_may_pull(skb, sizeof(*th))) 2478 goto out; 2479 2480 th = tcp_hdr(skb); 2481 thlen = th->doff * 4; 2482 if (thlen < sizeof(*th)) 2483 goto out; 2484 2485 if (!pskb_may_pull(skb, thlen)) 2486 goto out; 2487 2488 th = tcp_hdr(skb); 2489 __skb_pull(skb, thlen); 2490 2491 flags = tcp_flag_word(th); 2492 2493 for (; (p = *head); head = &p->next) { 2494 if (!NAPI_GRO_CB(p)->same_flow) 2495 continue; 2496 2497 th2 = tcp_hdr(p); 2498 2499 if (th->source != th2->source || th->dest != th2->dest) { 2500 NAPI_GRO_CB(p)->same_flow = 0; 2501 continue; 2502 } 2503 2504 goto found; 2505 } 2506 2507 goto out_check_final; 2508 2509found: 2510 flush = NAPI_GRO_CB(p)->flush; 2511 flush |= flags & TCP_FLAG_CWR; 2512 flush |= (flags ^ tcp_flag_word(th2)) & 2513 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH); 2514 flush |= th->ack_seq != th2->ack_seq || th->window != th2->window; 2515 flush |= memcmp(th + 1, th2 + 1, thlen - sizeof(*th)); 2516 2517 total = p->len; 2518 mss = skb_shinfo(p)->gso_size; 2519 2520 flush |= skb->len > mss || skb->len <= 0; 2521 flush |= ntohl(th2->seq) + total != ntohl(th->seq); 2522 2523 if (flush || skb_gro_receive(head, skb)) { 2524 mss = 1; 2525 goto out_check_final; 2526 } 2527 2528 p = *head; 2529 th2 = tcp_hdr(p); 2530 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); 2531 2532out_check_final: 2533 flush = skb->len < mss; 2534 flush |= flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST | 2535 TCP_FLAG_SYN | TCP_FLAG_FIN); 2536 2537 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) 2538 pp = head; 2539 2540out: 2541 NAPI_GRO_CB(skb)->flush |= flush; 2542 2543 return pp; 2544} 2545 2546int tcp_gro_complete(struct sk_buff *skb) 2547{ 2548 struct tcphdr *th = tcp_hdr(skb); 2549 2550 skb->csum_start = skb_transport_header(skb) - skb->head; 2551 skb->csum_offset = offsetof(struct tcphdr, check); 2552 skb->ip_summed = CHECKSUM_PARTIAL; 2553 2554 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 2555 2556 if (th->cwr) 2557 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 2558 2559 return 0; 2560} 2561 2562#ifdef CONFIG_TCP_MD5SIG 2563static unsigned long tcp_md5sig_users; 2564static struct tcp_md5sig_pool **tcp_md5sig_pool; 2565static DEFINE_SPINLOCK(tcp_md5sig_pool_lock); 2566 2567static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool) 2568{ 2569 int cpu; 2570 for_each_possible_cpu(cpu) { 2571 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu); 2572 if (p) { 2573 if (p->md5_desc.tfm) 2574 crypto_free_hash(p->md5_desc.tfm); 2575 kfree(p); 2576 p = NULL; 2577 } 2578 } 2579 free_percpu(pool); 2580} 2581 2582void tcp_free_md5sig_pool(void) 2583{ 2584 struct tcp_md5sig_pool **pool = NULL; 2585 2586 spin_lock_bh(&tcp_md5sig_pool_lock); 2587 if (--tcp_md5sig_users == 0) { 2588 pool = tcp_md5sig_pool; 2589 tcp_md5sig_pool = NULL; 2590 } 2591 spin_unlock_bh(&tcp_md5sig_pool_lock); 2592 if (pool) 2593 __tcp_free_md5sig_pool(pool); 2594} 2595 2596EXPORT_SYMBOL(tcp_free_md5sig_pool); 2597 2598static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void) 2599{ 2600 int cpu; 2601 struct tcp_md5sig_pool **pool; 2602 2603 pool = alloc_percpu(struct tcp_md5sig_pool *); 2604 if (!pool) 2605 return NULL; 2606 2607 for_each_possible_cpu(cpu) { 2608 struct tcp_md5sig_pool *p; 2609 struct crypto_hash *hash; 2610 2611 p = kzalloc(sizeof(*p), GFP_KERNEL); 2612 if (!p) 2613 goto out_free; 2614 *per_cpu_ptr(pool, cpu) = p; 2615 2616 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 2617 if (!hash || IS_ERR(hash)) 2618 goto out_free; 2619 2620 p->md5_desc.tfm = hash; 2621 } 2622 return pool; 2623out_free: 2624 __tcp_free_md5sig_pool(pool); 2625 return NULL; 2626} 2627 2628struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void) 2629{ 2630 struct tcp_md5sig_pool **pool; 2631 int alloc = 0; 2632 2633retry: 2634 spin_lock_bh(&tcp_md5sig_pool_lock); 2635 pool = tcp_md5sig_pool; 2636 if (tcp_md5sig_users++ == 0) { 2637 alloc = 1; 2638 spin_unlock_bh(&tcp_md5sig_pool_lock); 2639 } else if (!pool) { 2640 tcp_md5sig_users--; 2641 spin_unlock_bh(&tcp_md5sig_pool_lock); 2642 cpu_relax(); 2643 goto retry; 2644 } else 2645 spin_unlock_bh(&tcp_md5sig_pool_lock); 2646 2647 if (alloc) { 2648 /* we cannot hold spinlock here because this may sleep. */ 2649 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool(); 2650 spin_lock_bh(&tcp_md5sig_pool_lock); 2651 if (!p) { 2652 tcp_md5sig_users--; 2653 spin_unlock_bh(&tcp_md5sig_pool_lock); 2654 return NULL; 2655 } 2656 pool = tcp_md5sig_pool; 2657 if (pool) { 2658 /* oops, it has already been assigned. */ 2659 spin_unlock_bh(&tcp_md5sig_pool_lock); 2660 __tcp_free_md5sig_pool(p); 2661 } else { 2662 tcp_md5sig_pool = pool = p; 2663 spin_unlock_bh(&tcp_md5sig_pool_lock); 2664 } 2665 } 2666 return pool; 2667} 2668 2669EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 2670 2671struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu) 2672{ 2673 struct tcp_md5sig_pool **p; 2674 spin_lock_bh(&tcp_md5sig_pool_lock); 2675 p = tcp_md5sig_pool; 2676 if (p) 2677 tcp_md5sig_users++; 2678 spin_unlock_bh(&tcp_md5sig_pool_lock); 2679 return (p ? *per_cpu_ptr(p, cpu) : NULL); 2680} 2681 2682EXPORT_SYMBOL(__tcp_get_md5sig_pool); 2683 2684void __tcp_put_md5sig_pool(void) 2685{ 2686 tcp_free_md5sig_pool(); 2687} 2688 2689EXPORT_SYMBOL(__tcp_put_md5sig_pool); 2690 2691int tcp_md5_hash_header(struct tcp_md5sig_pool *hp, 2692 struct tcphdr *th) 2693{ 2694 struct scatterlist sg; 2695 int err; 2696 2697 __sum16 old_checksum = th->check; 2698 th->check = 0; 2699 /* options aren't included in the hash */ 2700 sg_init_one(&sg, th, sizeof(struct tcphdr)); 2701 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr)); 2702 th->check = old_checksum; 2703 return err; 2704} 2705 2706EXPORT_SYMBOL(tcp_md5_hash_header); 2707 2708int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, 2709 struct sk_buff *skb, unsigned header_len) 2710{ 2711 struct scatterlist sg; 2712 const struct tcphdr *tp = tcp_hdr(skb); 2713 struct hash_desc *desc = &hp->md5_desc; 2714 unsigned i; 2715 const unsigned head_data_len = skb_headlen(skb) > header_len ? 2716 skb_headlen(skb) - header_len : 0; 2717 const struct skb_shared_info *shi = skb_shinfo(skb); 2718 2719 sg_init_table(&sg, 1); 2720 2721 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len); 2722 if (crypto_hash_update(desc, &sg, head_data_len)) 2723 return 1; 2724 2725 for (i = 0; i < shi->nr_frags; ++i) { 2726 const struct skb_frag_struct *f = &shi->frags[i]; 2727 sg_set_page(&sg, f->page, f->size, f->page_offset); 2728 if (crypto_hash_update(desc, &sg, f->size)) 2729 return 1; 2730 } 2731 2732 return 0; 2733} 2734 2735EXPORT_SYMBOL(tcp_md5_hash_skb_data); 2736 2737int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key) 2738{ 2739 struct scatterlist sg; 2740 2741 sg_init_one(&sg, key->key, key->keylen); 2742 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen); 2743} 2744 2745EXPORT_SYMBOL(tcp_md5_hash_key); 2746 2747#endif 2748 2749void tcp_done(struct sock *sk) 2750{ 2751 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 2752 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS); 2753 2754 tcp_set_state(sk, TCP_CLOSE); 2755 tcp_clear_xmit_timers(sk); 2756 2757 sk->sk_shutdown = SHUTDOWN_MASK; 2758 2759 if (!sock_flag(sk, SOCK_DEAD)) 2760 sk->sk_state_change(sk); 2761 else 2762 inet_csk_destroy_sock(sk); 2763} 2764EXPORT_SYMBOL_GPL(tcp_done); 2765 2766extern struct tcp_congestion_ops tcp_reno; 2767 2768static __initdata unsigned long thash_entries; 2769static int __init set_thash_entries(char *str) 2770{ 2771 if (!str) 2772 return 0; 2773 thash_entries = simple_strtoul(str, &str, 0); 2774 return 1; 2775} 2776__setup("thash_entries=", set_thash_entries); 2777 2778void __init tcp_init(void) 2779{ 2780 struct sk_buff *skb = NULL; 2781 unsigned long nr_pages, limit; 2782 int order, i, max_share; 2783 2784 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb)); 2785 2786 percpu_counter_init(&tcp_sockets_allocated, 0); 2787 percpu_counter_init(&tcp_orphan_count, 0); 2788 tcp_hashinfo.bind_bucket_cachep = 2789 kmem_cache_create("tcp_bind_bucket", 2790 sizeof(struct inet_bind_bucket), 0, 2791 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 2792 2793 /* Size and allocate the main established and bind bucket 2794 * hash tables. 2795 * 2796 * The methodology is similar to that of the buffer cache. 2797 */ 2798 tcp_hashinfo.ehash = 2799 alloc_large_system_hash("TCP established", 2800 sizeof(struct inet_ehash_bucket), 2801 thash_entries, 2802 (num_physpages >= 128 * 1024) ? 2803 13 : 15, 2804 0, 2805 &tcp_hashinfo.ehash_size, 2806 NULL, 2807 thash_entries ? 0 : 512 * 1024); 2808 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size; 2809 for (i = 0; i < tcp_hashinfo.ehash_size; i++) { 2810 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i); 2811 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i); 2812 } 2813 if (inet_ehash_locks_alloc(&tcp_hashinfo)) 2814 panic("TCP: failed to alloc ehash_locks"); 2815 tcp_hashinfo.bhash = 2816 alloc_large_system_hash("TCP bind", 2817 sizeof(struct inet_bind_hashbucket), 2818 tcp_hashinfo.ehash_size, 2819 (num_physpages >= 128 * 1024) ? 2820 13 : 15, 2821 0, 2822 &tcp_hashinfo.bhash_size, 2823 NULL, 2824 64 * 1024); 2825 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size; 2826 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 2827 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 2828 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 2829 } 2830 2831 /* Try to be a bit smarter and adjust defaults depending 2832 * on available memory. 2833 */ 2834 for (order = 0; ((1 << order) << PAGE_SHIFT) < 2835 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket)); 2836 order++) 2837 ; 2838 if (order >= 4) { 2839 tcp_death_row.sysctl_max_tw_buckets = 180000; 2840 sysctl_tcp_max_orphans = 4096 << (order - 4); 2841 sysctl_max_syn_backlog = 1024; 2842 } else if (order < 3) { 2843 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order); 2844 sysctl_tcp_max_orphans >>= (3 - order); 2845 sysctl_max_syn_backlog = 128; 2846 } 2847 2848 /* Set the pressure threshold to be a fraction of global memory that 2849 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of 2850 * memory, with a floor of 128 pages. 2851 */ 2852 nr_pages = totalram_pages - totalhigh_pages; 2853 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); 2854 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); 2855 limit = max(limit, 128UL); 2856 sysctl_tcp_mem[0] = limit / 4 * 3; 2857 sysctl_tcp_mem[1] = limit; 2858 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; 2859 2860 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 2861 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7); 2862 max_share = min(4UL*1024*1024, limit); 2863 2864 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM; 2865 sysctl_tcp_wmem[1] = 16*1024; 2866 sysctl_tcp_wmem[2] = max(64*1024, max_share); 2867 2868 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; 2869 sysctl_tcp_rmem[1] = 87380; 2870 sysctl_tcp_rmem[2] = max(87380, max_share); 2871 2872 printk(KERN_INFO "TCP: Hash tables configured " 2873 "(established %d bind %d)\n", 2874 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size); 2875 2876 tcp_register_congestion_control(&tcp_reno); 2877} 2878 2879EXPORT_SYMBOL(tcp_close); 2880EXPORT_SYMBOL(tcp_disconnect); 2881EXPORT_SYMBOL(tcp_getsockopt); 2882EXPORT_SYMBOL(tcp_ioctl); 2883EXPORT_SYMBOL(tcp_poll); 2884EXPORT_SYMBOL(tcp_read_sock); 2885EXPORT_SYMBOL(tcp_recvmsg); 2886EXPORT_SYMBOL(tcp_sendmsg); 2887EXPORT_SYMBOL(tcp_splice_read); 2888EXPORT_SYMBOL(tcp_sendpage); 2889EXPORT_SYMBOL(tcp_setsockopt); 2890EXPORT_SYMBOL(tcp_shutdown); 2891