tcp.c revision 3ff50b7997fe06cd5d276b229967bb52d6b3b6c1
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 * Version: $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $ 9 * 10 * Authors: Ross Biro 11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 12 * Mark Evans, <evansmp@uhura.aston.ac.uk> 13 * Corey Minyard <wf-rch!minyard@relay.EU.net> 14 * Florian La Roche, <flla@stud.uni-sb.de> 15 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu> 16 * Linus Torvalds, <torvalds@cs.helsinki.fi> 17 * Alan Cox, <gw4pts@gw4pts.ampr.org> 18 * Matthew Dillon, <dillon@apollo.west.oic.com> 19 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 20 * Jorge Cwik, <jorge@laser.satlink.net> 21 * 22 * Fixes: 23 * Alan Cox : Numerous verify_area() calls 24 * Alan Cox : Set the ACK bit on a reset 25 * Alan Cox : Stopped it crashing if it closed while 26 * sk->inuse=1 and was trying to connect 27 * (tcp_err()). 28 * Alan Cox : All icmp error handling was broken 29 * pointers passed where wrong and the 30 * socket was looked up backwards. Nobody 31 * tested any icmp error code obviously. 32 * Alan Cox : tcp_err() now handled properly. It 33 * wakes people on errors. poll 34 * behaves and the icmp error race 35 * has gone by moving it into sock.c 36 * Alan Cox : tcp_send_reset() fixed to work for 37 * everything not just packets for 38 * unknown sockets. 39 * Alan Cox : tcp option processing. 40 * Alan Cox : Reset tweaked (still not 100%) [Had 41 * syn rule wrong] 42 * Herp Rosmanith : More reset fixes 43 * Alan Cox : No longer acks invalid rst frames. 44 * Acking any kind of RST is right out. 45 * Alan Cox : Sets an ignore me flag on an rst 46 * receive otherwise odd bits of prattle 47 * escape still 48 * Alan Cox : Fixed another acking RST frame bug. 49 * Should stop LAN workplace lockups. 50 * Alan Cox : Some tidyups using the new skb list 51 * facilities 52 * Alan Cox : sk->keepopen now seems to work 53 * Alan Cox : Pulls options out correctly on accepts 54 * Alan Cox : Fixed assorted sk->rqueue->next errors 55 * Alan Cox : PSH doesn't end a TCP read. Switched a 56 * bit to skb ops. 57 * Alan Cox : Tidied tcp_data to avoid a potential 58 * nasty. 59 * Alan Cox : Added some better commenting, as the 60 * tcp is hard to follow 61 * Alan Cox : Removed incorrect check for 20 * psh 62 * Michael O'Reilly : ack < copied bug fix. 63 * Johannes Stille : Misc tcp fixes (not all in yet). 64 * Alan Cox : FIN with no memory -> CRASH 65 * Alan Cox : Added socket option proto entries. 66 * Also added awareness of them to accept. 67 * Alan Cox : Added TCP options (SOL_TCP) 68 * Alan Cox : Switched wakeup calls to callbacks, 69 * so the kernel can layer network 70 * sockets. 71 * Alan Cox : Use ip_tos/ip_ttl settings. 72 * Alan Cox : Handle FIN (more) properly (we hope). 73 * Alan Cox : RST frames sent on unsynchronised 74 * state ack error. 75 * Alan Cox : Put in missing check for SYN bit. 76 * Alan Cox : Added tcp_select_window() aka NET2E 77 * window non shrink trick. 78 * Alan Cox : Added a couple of small NET2E timer 79 * fixes 80 * Charles Hedrick : TCP fixes 81 * Toomas Tamm : TCP window fixes 82 * Alan Cox : Small URG fix to rlogin ^C ack fight 83 * Charles Hedrick : Rewrote most of it to actually work 84 * Linus : Rewrote tcp_read() and URG handling 85 * completely 86 * Gerhard Koerting: Fixed some missing timer handling 87 * Matthew Dillon : Reworked TCP machine states as per RFC 88 * Gerhard Koerting: PC/TCP workarounds 89 * Adam Caldwell : Assorted timer/timing errors 90 * Matthew Dillon : Fixed another RST bug 91 * Alan Cox : Move to kernel side addressing changes. 92 * Alan Cox : Beginning work on TCP fastpathing 93 * (not yet usable) 94 * Arnt Gulbrandsen: Turbocharged tcp_check() routine. 95 * Alan Cox : TCP fast path debugging 96 * Alan Cox : Window clamping 97 * Michael Riepe : Bug in tcp_check() 98 * Matt Dillon : More TCP improvements and RST bug fixes 99 * Matt Dillon : Yet more small nasties remove from the 100 * TCP code (Be very nice to this man if 101 * tcp finally works 100%) 8) 102 * Alan Cox : BSD accept semantics. 103 * Alan Cox : Reset on closedown bug. 104 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto(). 105 * Michael Pall : Handle poll() after URG properly in 106 * all cases. 107 * Michael Pall : Undo the last fix in tcp_read_urg() 108 * (multi URG PUSH broke rlogin). 109 * Michael Pall : Fix the multi URG PUSH problem in 110 * tcp_readable(), poll() after URG 111 * works now. 112 * Michael Pall : recv(...,MSG_OOB) never blocks in the 113 * BSD api. 114 * Alan Cox : Changed the semantics of sk->socket to 115 * fix a race and a signal problem with 116 * accept() and async I/O. 117 * Alan Cox : Relaxed the rules on tcp_sendto(). 118 * Yury Shevchuk : Really fixed accept() blocking problem. 119 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for 120 * clients/servers which listen in on 121 * fixed ports. 122 * Alan Cox : Cleaned the above up and shrank it to 123 * a sensible code size. 124 * Alan Cox : Self connect lockup fix. 125 * Alan Cox : No connect to multicast. 126 * Ross Biro : Close unaccepted children on master 127 * socket close. 128 * Alan Cox : Reset tracing code. 129 * Alan Cox : Spurious resets on shutdown. 130 * Alan Cox : Giant 15 minute/60 second timer error 131 * Alan Cox : Small whoops in polling before an 132 * accept. 133 * Alan Cox : Kept the state trace facility since 134 * it's handy for debugging. 135 * Alan Cox : More reset handler fixes. 136 * Alan Cox : Started rewriting the code based on 137 * the RFC's for other useful protocol 138 * references see: Comer, KA9Q NOS, and 139 * for a reference on the difference 140 * between specifications and how BSD 141 * works see the 4.4lite source. 142 * A.N.Kuznetsov : Don't time wait on completion of tidy 143 * close. 144 * Linus Torvalds : Fin/Shutdown & copied_seq changes. 145 * Linus Torvalds : Fixed BSD port reuse to work first syn 146 * Alan Cox : Reimplemented timers as per the RFC 147 * and using multiple timers for sanity. 148 * Alan Cox : Small bug fixes, and a lot of new 149 * comments. 150 * Alan Cox : Fixed dual reader crash by locking 151 * the buffers (much like datagram.c) 152 * Alan Cox : Fixed stuck sockets in probe. A probe 153 * now gets fed up of retrying without 154 * (even a no space) answer. 155 * Alan Cox : Extracted closing code better 156 * Alan Cox : Fixed the closing state machine to 157 * resemble the RFC. 158 * Alan Cox : More 'per spec' fixes. 159 * Jorge Cwik : Even faster checksumming. 160 * Alan Cox : tcp_data() doesn't ack illegal PSH 161 * only frames. At least one pc tcp stack 162 * generates them. 163 * Alan Cox : Cache last socket. 164 * Alan Cox : Per route irtt. 165 * Matt Day : poll()->select() match BSD precisely on error 166 * Alan Cox : New buffers 167 * Marc Tamsky : Various sk->prot->retransmits and 168 * sk->retransmits misupdating fixed. 169 * Fixed tcp_write_timeout: stuck close, 170 * and TCP syn retries gets used now. 171 * Mark Yarvis : In tcp_read_wakeup(), don't send an 172 * ack if state is TCP_CLOSED. 173 * Alan Cox : Look up device on a retransmit - routes may 174 * change. Doesn't yet cope with MSS shrink right 175 * but it's a start! 176 * Marc Tamsky : Closing in closing fixes. 177 * Mike Shaver : RFC1122 verifications. 178 * Alan Cox : rcv_saddr errors. 179 * Alan Cox : Block double connect(). 180 * Alan Cox : Small hooks for enSKIP. 181 * Alexey Kuznetsov: Path MTU discovery. 182 * Alan Cox : Support soft errors. 183 * Alan Cox : Fix MTU discovery pathological case 184 * when the remote claims no mtu! 185 * Marc Tamsky : TCP_CLOSE fix. 186 * Colin (G3TNE) : Send a reset on syn ack replies in 187 * window but wrong (fixes NT lpd problems) 188 * Pedro Roque : Better TCP window handling, delayed ack. 189 * Joerg Reuter : No modification of locked buffers in 190 * tcp_do_retransmit() 191 * Eric Schenk : Changed receiver side silly window 192 * avoidance algorithm to BSD style 193 * algorithm. This doubles throughput 194 * against machines running Solaris, 195 * and seems to result in general 196 * improvement. 197 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD 198 * Willy Konynenberg : Transparent proxying support. 199 * Mike McLagan : Routing by source 200 * Keith Owens : Do proper merging with partial SKB's in 201 * tcp_do_sendmsg to avoid burstiness. 202 * Eric Schenk : Fix fast close down bug with 203 * shutdown() followed by close(). 204 * Andi Kleen : Make poll agree with SIGIO 205 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and 206 * lingertime == 0 (RFC 793 ABORT Call) 207 * Hirokazu Takahashi : Use copy_from_user() instead of 208 * csum_and_copy_from_user() if possible. 209 * 210 * This program is free software; you can redistribute it and/or 211 * modify it under the terms of the GNU General Public License 212 * as published by the Free Software Foundation; either version 213 * 2 of the License, or(at your option) any later version. 214 * 215 * Description of States: 216 * 217 * TCP_SYN_SENT sent a connection request, waiting for ack 218 * 219 * TCP_SYN_RECV received a connection request, sent ack, 220 * waiting for final ack in three-way handshake. 221 * 222 * TCP_ESTABLISHED connection established 223 * 224 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete 225 * transmission of remaining buffered data 226 * 227 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote 228 * to shutdown 229 * 230 * TCP_CLOSING both sides have shutdown but we still have 231 * data we have to finish sending 232 * 233 * TCP_TIME_WAIT timeout to catch resent junk before entering 234 * closed, can only be entered from FIN_WAIT2 235 * or CLOSING. Required because the other end 236 * may not have gotten our last ACK causing it 237 * to retransmit the data packet (which we ignore) 238 * 239 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for 240 * us to finish writing our data and to shutdown 241 * (we have to close() to move on to LAST_ACK) 242 * 243 * TCP_LAST_ACK out side has shutdown after remote has 244 * shutdown. There may still be data in our 245 * buffer that we have to finish sending 246 * 247 * TCP_CLOSE socket is finished 248 */ 249 250#include <linux/module.h> 251#include <linux/types.h> 252#include <linux/fcntl.h> 253#include <linux/poll.h> 254#include <linux/init.h> 255#include <linux/smp_lock.h> 256#include <linux/fs.h> 257#include <linux/random.h> 258#include <linux/bootmem.h> 259#include <linux/cache.h> 260#include <linux/err.h> 261#include <linux/crypto.h> 262 263#include <net/icmp.h> 264#include <net/tcp.h> 265#include <net/xfrm.h> 266#include <net/ip.h> 267#include <net/netdma.h> 268 269#include <asm/uaccess.h> 270#include <asm/ioctls.h> 271 272int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 273 274DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly; 275 276atomic_t tcp_orphan_count = ATOMIC_INIT(0); 277 278EXPORT_SYMBOL_GPL(tcp_orphan_count); 279 280int sysctl_tcp_mem[3] __read_mostly; 281int sysctl_tcp_wmem[3] __read_mostly; 282int sysctl_tcp_rmem[3] __read_mostly; 283 284EXPORT_SYMBOL(sysctl_tcp_mem); 285EXPORT_SYMBOL(sysctl_tcp_rmem); 286EXPORT_SYMBOL(sysctl_tcp_wmem); 287 288atomic_t tcp_memory_allocated; /* Current allocated memory. */ 289atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */ 290 291EXPORT_SYMBOL(tcp_memory_allocated); 292EXPORT_SYMBOL(tcp_sockets_allocated); 293 294/* 295 * Pressure flag: try to collapse. 296 * Technical note: it is used by multiple contexts non atomically. 297 * All the sk_stream_mem_schedule() is of this nature: accounting 298 * is strict, actions are advisory and have some latency. 299 */ 300int tcp_memory_pressure __read_mostly; 301 302EXPORT_SYMBOL(tcp_memory_pressure); 303 304void tcp_enter_memory_pressure(void) 305{ 306 if (!tcp_memory_pressure) { 307 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES); 308 tcp_memory_pressure = 1; 309 } 310} 311 312EXPORT_SYMBOL(tcp_enter_memory_pressure); 313 314/* 315 * Wait for a TCP event. 316 * 317 * Note that we don't need to lock the socket, as the upper poll layers 318 * take care of normal races (between the test and the event) and we don't 319 * go look at any of the socket buffers directly. 320 */ 321unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 322{ 323 unsigned int mask; 324 struct sock *sk = sock->sk; 325 struct tcp_sock *tp = tcp_sk(sk); 326 327 poll_wait(file, sk->sk_sleep, wait); 328 if (sk->sk_state == TCP_LISTEN) 329 return inet_csk_listen_poll(sk); 330 331 /* Socket is not locked. We are protected from async events 332 by poll logic and correct handling of state changes 333 made by another threads is impossible in any case. 334 */ 335 336 mask = 0; 337 if (sk->sk_err) 338 mask = POLLERR; 339 340 /* 341 * POLLHUP is certainly not done right. But poll() doesn't 342 * have a notion of HUP in just one direction, and for a 343 * socket the read side is more interesting. 344 * 345 * Some poll() documentation says that POLLHUP is incompatible 346 * with the POLLOUT/POLLWR flags, so somebody should check this 347 * all. But careful, it tends to be safer to return too many 348 * bits than too few, and you can easily break real applications 349 * if you don't tell them that something has hung up! 350 * 351 * Check-me. 352 * 353 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 354 * our fs/select.c). It means that after we received EOF, 355 * poll always returns immediately, making impossible poll() on write() 356 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 357 * if and only if shutdown has been made in both directions. 358 * Actually, it is interesting to look how Solaris and DUX 359 * solve this dilemma. I would prefer, if PULLHUP were maskable, 360 * then we could set it on SND_SHUTDOWN. BTW examples given 361 * in Stevens' books assume exactly this behaviour, it explains 362 * why PULLHUP is incompatible with POLLOUT. --ANK 363 * 364 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 365 * blocking on fresh not-connected or disconnected socket. --ANK 366 */ 367 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 368 mask |= POLLHUP; 369 if (sk->sk_shutdown & RCV_SHUTDOWN) 370 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 371 372 /* Connected? */ 373 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) { 374 /* Potential race condition. If read of tp below will 375 * escape above sk->sk_state, we can be illegally awaken 376 * in SYN_* states. */ 377 if ((tp->rcv_nxt != tp->copied_seq) && 378 (tp->urg_seq != tp->copied_seq || 379 tp->rcv_nxt != tp->copied_seq + 1 || 380 sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data)) 381 mask |= POLLIN | POLLRDNORM; 382 383 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 384 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) { 385 mask |= POLLOUT | POLLWRNORM; 386 } else { /* send SIGIO later */ 387 set_bit(SOCK_ASYNC_NOSPACE, 388 &sk->sk_socket->flags); 389 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 390 391 /* Race breaker. If space is freed after 392 * wspace test but before the flags are set, 393 * IO signal will be lost. 394 */ 395 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) 396 mask |= POLLOUT | POLLWRNORM; 397 } 398 } 399 400 if (tp->urg_data & TCP_URG_VALID) 401 mask |= POLLPRI; 402 } 403 return mask; 404} 405 406int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 407{ 408 struct tcp_sock *tp = tcp_sk(sk); 409 int answ; 410 411 switch (cmd) { 412 case SIOCINQ: 413 if (sk->sk_state == TCP_LISTEN) 414 return -EINVAL; 415 416 lock_sock(sk); 417 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 418 answ = 0; 419 else if (sock_flag(sk, SOCK_URGINLINE) || 420 !tp->urg_data || 421 before(tp->urg_seq, tp->copied_seq) || 422 !before(tp->urg_seq, tp->rcv_nxt)) { 423 answ = tp->rcv_nxt - tp->copied_seq; 424 425 /* Subtract 1, if FIN is in queue. */ 426 if (answ && !skb_queue_empty(&sk->sk_receive_queue)) 427 answ -= 428 tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin; 429 } else 430 answ = tp->urg_seq - tp->copied_seq; 431 release_sock(sk); 432 break; 433 case SIOCATMARK: 434 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 435 break; 436 case SIOCOUTQ: 437 if (sk->sk_state == TCP_LISTEN) 438 return -EINVAL; 439 440 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 441 answ = 0; 442 else 443 answ = tp->write_seq - tp->snd_una; 444 break; 445 default: 446 return -ENOIOCTLCMD; 447 } 448 449 return put_user(answ, (int __user *)arg); 450} 451 452static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 453{ 454 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH; 455 tp->pushed_seq = tp->write_seq; 456} 457 458static inline int forced_push(struct tcp_sock *tp) 459{ 460 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 461} 462 463static inline void skb_entail(struct sock *sk, struct tcp_sock *tp, 464 struct sk_buff *skb) 465{ 466 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 467 468 skb->csum = 0; 469 tcb->seq = tcb->end_seq = tp->write_seq; 470 tcb->flags = TCPCB_FLAG_ACK; 471 tcb->sacked = 0; 472 skb_header_release(skb); 473 tcp_add_write_queue_tail(sk, skb); 474 sk_charge_skb(sk, skb); 475 if (tp->nonagle & TCP_NAGLE_PUSH) 476 tp->nonagle &= ~TCP_NAGLE_PUSH; 477} 478 479static inline void tcp_mark_urg(struct tcp_sock *tp, int flags, 480 struct sk_buff *skb) 481{ 482 if (flags & MSG_OOB) { 483 tp->urg_mode = 1; 484 tp->snd_up = tp->write_seq; 485 TCP_SKB_CB(skb)->sacked |= TCPCB_URG; 486 } 487} 488 489static inline void tcp_push(struct sock *sk, struct tcp_sock *tp, int flags, 490 int mss_now, int nonagle) 491{ 492 if (tcp_send_head(sk)) { 493 struct sk_buff *skb = tcp_write_queue_tail(sk); 494 if (!(flags & MSG_MORE) || forced_push(tp)) 495 tcp_mark_push(tp, skb); 496 tcp_mark_urg(tp, flags, skb); 497 __tcp_push_pending_frames(sk, tp, mss_now, 498 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle); 499 } 500} 501 502static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, 503 size_t psize, int flags) 504{ 505 struct tcp_sock *tp = tcp_sk(sk); 506 int mss_now, size_goal; 507 int err; 508 ssize_t copied; 509 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 510 511 /* Wait for a connection to finish. */ 512 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 513 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 514 goto out_err; 515 516 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 517 518 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 519 size_goal = tp->xmit_size_goal; 520 copied = 0; 521 522 err = -EPIPE; 523 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 524 goto do_error; 525 526 while (psize > 0) { 527 struct sk_buff *skb = tcp_write_queue_tail(sk); 528 struct page *page = pages[poffset / PAGE_SIZE]; 529 int copy, i, can_coalesce; 530 int offset = poffset % PAGE_SIZE; 531 int size = min_t(size_t, psize, PAGE_SIZE - offset); 532 533 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { 534new_segment: 535 if (!sk_stream_memory_free(sk)) 536 goto wait_for_sndbuf; 537 538 skb = sk_stream_alloc_pskb(sk, 0, 0, 539 sk->sk_allocation); 540 if (!skb) 541 goto wait_for_memory; 542 543 skb_entail(sk, tp, skb); 544 copy = size_goal; 545 } 546 547 if (copy > size) 548 copy = size; 549 550 i = skb_shinfo(skb)->nr_frags; 551 can_coalesce = skb_can_coalesce(skb, i, page, offset); 552 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 553 tcp_mark_push(tp, skb); 554 goto new_segment; 555 } 556 if (!sk_stream_wmem_schedule(sk, copy)) 557 goto wait_for_memory; 558 559 if (can_coalesce) { 560 skb_shinfo(skb)->frags[i - 1].size += copy; 561 } else { 562 get_page(page); 563 skb_fill_page_desc(skb, i, page, offset, copy); 564 } 565 566 skb->len += copy; 567 skb->data_len += copy; 568 skb->truesize += copy; 569 sk->sk_wmem_queued += copy; 570 sk->sk_forward_alloc -= copy; 571 skb->ip_summed = CHECKSUM_PARTIAL; 572 tp->write_seq += copy; 573 TCP_SKB_CB(skb)->end_seq += copy; 574 skb_shinfo(skb)->gso_segs = 0; 575 576 if (!copied) 577 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH; 578 579 copied += copy; 580 poffset += copy; 581 if (!(psize -= copy)) 582 goto out; 583 584 if (skb->len < mss_now || (flags & MSG_OOB)) 585 continue; 586 587 if (forced_push(tp)) { 588 tcp_mark_push(tp, skb); 589 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH); 590 } else if (skb == tcp_send_head(sk)) 591 tcp_push_one(sk, mss_now); 592 continue; 593 594wait_for_sndbuf: 595 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 596wait_for_memory: 597 if (copied) 598 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 599 600 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 601 goto do_error; 602 603 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 604 size_goal = tp->xmit_size_goal; 605 } 606 607out: 608 if (copied) 609 tcp_push(sk, tp, flags, mss_now, tp->nonagle); 610 return copied; 611 612do_error: 613 if (copied) 614 goto out; 615out_err: 616 return sk_stream_error(sk, flags, err); 617} 618 619ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, 620 size_t size, int flags) 621{ 622 ssize_t res; 623 struct sock *sk = sock->sk; 624 625 if (!(sk->sk_route_caps & NETIF_F_SG) || 626 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 627 return sock_no_sendpage(sock, page, offset, size, flags); 628 629 lock_sock(sk); 630 TCP_CHECK_TIMER(sk); 631 res = do_tcp_sendpages(sk, &page, offset, size, flags); 632 TCP_CHECK_TIMER(sk); 633 release_sock(sk); 634 return res; 635} 636 637#define TCP_PAGE(sk) (sk->sk_sndmsg_page) 638#define TCP_OFF(sk) (sk->sk_sndmsg_off) 639 640static inline int select_size(struct sock *sk, struct tcp_sock *tp) 641{ 642 int tmp = tp->mss_cache; 643 644 if (sk->sk_route_caps & NETIF_F_SG) { 645 if (sk_can_gso(sk)) 646 tmp = 0; 647 else { 648 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 649 650 if (tmp >= pgbreak && 651 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 652 tmp = pgbreak; 653 } 654 } 655 656 return tmp; 657} 658 659int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 660 size_t size) 661{ 662 struct iovec *iov; 663 struct tcp_sock *tp = tcp_sk(sk); 664 struct sk_buff *skb; 665 int iovlen, flags; 666 int mss_now, size_goal; 667 int err, copied; 668 long timeo; 669 670 lock_sock(sk); 671 TCP_CHECK_TIMER(sk); 672 673 flags = msg->msg_flags; 674 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 675 676 /* Wait for a connection to finish. */ 677 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 678 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 679 goto out_err; 680 681 /* This should be in poll */ 682 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 683 684 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 685 size_goal = tp->xmit_size_goal; 686 687 /* Ok commence sending. */ 688 iovlen = msg->msg_iovlen; 689 iov = msg->msg_iov; 690 copied = 0; 691 692 err = -EPIPE; 693 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 694 goto do_error; 695 696 while (--iovlen >= 0) { 697 int seglen = iov->iov_len; 698 unsigned char __user *from = iov->iov_base; 699 700 iov++; 701 702 while (seglen > 0) { 703 int copy; 704 705 skb = tcp_write_queue_tail(sk); 706 707 if (!tcp_send_head(sk) || 708 (copy = size_goal - skb->len) <= 0) { 709 710new_segment: 711 /* Allocate new segment. If the interface is SG, 712 * allocate skb fitting to single page. 713 */ 714 if (!sk_stream_memory_free(sk)) 715 goto wait_for_sndbuf; 716 717 skb = sk_stream_alloc_pskb(sk, select_size(sk, tp), 718 0, sk->sk_allocation); 719 if (!skb) 720 goto wait_for_memory; 721 722 /* 723 * Check whether we can use HW checksum. 724 */ 725 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 726 skb->ip_summed = CHECKSUM_PARTIAL; 727 728 skb_entail(sk, tp, skb); 729 copy = size_goal; 730 } 731 732 /* Try to append data to the end of skb. */ 733 if (copy > seglen) 734 copy = seglen; 735 736 /* Where to copy to? */ 737 if (skb_tailroom(skb) > 0) { 738 /* We have some space in skb head. Superb! */ 739 if (copy > skb_tailroom(skb)) 740 copy = skb_tailroom(skb); 741 if ((err = skb_add_data(skb, from, copy)) != 0) 742 goto do_fault; 743 } else { 744 int merge = 0; 745 int i = skb_shinfo(skb)->nr_frags; 746 struct page *page = TCP_PAGE(sk); 747 int off = TCP_OFF(sk); 748 749 if (skb_can_coalesce(skb, i, page, off) && 750 off != PAGE_SIZE) { 751 /* We can extend the last page 752 * fragment. */ 753 merge = 1; 754 } else if (i == MAX_SKB_FRAGS || 755 (!i && 756 !(sk->sk_route_caps & NETIF_F_SG))) { 757 /* Need to add new fragment and cannot 758 * do this because interface is non-SG, 759 * or because all the page slots are 760 * busy. */ 761 tcp_mark_push(tp, skb); 762 goto new_segment; 763 } else if (page) { 764 if (off == PAGE_SIZE) { 765 put_page(page); 766 TCP_PAGE(sk) = page = NULL; 767 off = 0; 768 } 769 } else 770 off = 0; 771 772 if (copy > PAGE_SIZE - off) 773 copy = PAGE_SIZE - off; 774 775 if (!sk_stream_wmem_schedule(sk, copy)) 776 goto wait_for_memory; 777 778 if (!page) { 779 /* Allocate new cache page. */ 780 if (!(page = sk_stream_alloc_page(sk))) 781 goto wait_for_memory; 782 } 783 784 /* Time to copy data. We are close to 785 * the end! */ 786 err = skb_copy_to_page(sk, from, skb, page, 787 off, copy); 788 if (err) { 789 /* If this page was new, give it to the 790 * socket so it does not get leaked. 791 */ 792 if (!TCP_PAGE(sk)) { 793 TCP_PAGE(sk) = page; 794 TCP_OFF(sk) = 0; 795 } 796 goto do_error; 797 } 798 799 /* Update the skb. */ 800 if (merge) { 801 skb_shinfo(skb)->frags[i - 1].size += 802 copy; 803 } else { 804 skb_fill_page_desc(skb, i, page, off, copy); 805 if (TCP_PAGE(sk)) { 806 get_page(page); 807 } else if (off + copy < PAGE_SIZE) { 808 get_page(page); 809 TCP_PAGE(sk) = page; 810 } 811 } 812 813 TCP_OFF(sk) = off + copy; 814 } 815 816 if (!copied) 817 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH; 818 819 tp->write_seq += copy; 820 TCP_SKB_CB(skb)->end_seq += copy; 821 skb_shinfo(skb)->gso_segs = 0; 822 823 from += copy; 824 copied += copy; 825 if ((seglen -= copy) == 0 && iovlen == 0) 826 goto out; 827 828 if (skb->len < mss_now || (flags & MSG_OOB)) 829 continue; 830 831 if (forced_push(tp)) { 832 tcp_mark_push(tp, skb); 833 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH); 834 } else if (skb == tcp_send_head(sk)) 835 tcp_push_one(sk, mss_now); 836 continue; 837 838wait_for_sndbuf: 839 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 840wait_for_memory: 841 if (copied) 842 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 843 844 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 845 goto do_error; 846 847 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 848 size_goal = tp->xmit_size_goal; 849 } 850 } 851 852out: 853 if (copied) 854 tcp_push(sk, tp, flags, mss_now, tp->nonagle); 855 TCP_CHECK_TIMER(sk); 856 release_sock(sk); 857 return copied; 858 859do_fault: 860 if (!skb->len) { 861 tcp_unlink_write_queue(skb, sk); 862 /* It is the one place in all of TCP, except connection 863 * reset, where we can be unlinking the send_head. 864 */ 865 tcp_check_send_head(sk, skb); 866 sk_stream_free_skb(sk, skb); 867 } 868 869do_error: 870 if (copied) 871 goto out; 872out_err: 873 err = sk_stream_error(sk, flags, err); 874 TCP_CHECK_TIMER(sk); 875 release_sock(sk); 876 return err; 877} 878 879/* 880 * Handle reading urgent data. BSD has very simple semantics for 881 * this, no blocking and very strange errors 8) 882 */ 883 884static int tcp_recv_urg(struct sock *sk, long timeo, 885 struct msghdr *msg, int len, int flags, 886 int *addr_len) 887{ 888 struct tcp_sock *tp = tcp_sk(sk); 889 890 /* No URG data to read. */ 891 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || 892 tp->urg_data == TCP_URG_READ) 893 return -EINVAL; /* Yes this is right ! */ 894 895 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) 896 return -ENOTCONN; 897 898 if (tp->urg_data & TCP_URG_VALID) { 899 int err = 0; 900 char c = tp->urg_data; 901 902 if (!(flags & MSG_PEEK)) 903 tp->urg_data = TCP_URG_READ; 904 905 /* Read urgent data. */ 906 msg->msg_flags |= MSG_OOB; 907 908 if (len > 0) { 909 if (!(flags & MSG_TRUNC)) 910 err = memcpy_toiovec(msg->msg_iov, &c, 1); 911 len = 1; 912 } else 913 msg->msg_flags |= MSG_TRUNC; 914 915 return err ? -EFAULT : len; 916 } 917 918 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 919 return 0; 920 921 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and 922 * the available implementations agree in this case: 923 * this call should never block, independent of the 924 * blocking state of the socket. 925 * Mike <pall@rz.uni-karlsruhe.de> 926 */ 927 return -EAGAIN; 928} 929 930/* Clean up the receive buffer for full frames taken by the user, 931 * then send an ACK if necessary. COPIED is the number of bytes 932 * tcp_recvmsg has given to the user so far, it speeds up the 933 * calculation of whether or not we must ACK for the sake of 934 * a window update. 935 */ 936void tcp_cleanup_rbuf(struct sock *sk, int copied) 937{ 938 struct tcp_sock *tp = tcp_sk(sk); 939 int time_to_ack = 0; 940 941#if TCP_DEBUG 942 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); 943 944 BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq)); 945#endif 946 947 if (inet_csk_ack_scheduled(sk)) { 948 const struct inet_connection_sock *icsk = inet_csk(sk); 949 /* Delayed ACKs frequently hit locked sockets during bulk 950 * receive. */ 951 if (icsk->icsk_ack.blocked || 952 /* Once-per-two-segments ACK was not sent by tcp_input.c */ 953 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || 954 /* 955 * If this read emptied read buffer, we send ACK, if 956 * connection is not bidirectional, user drained 957 * receive buffer and there was a small segment 958 * in queue. 959 */ 960 (copied > 0 && 961 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || 962 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && 963 !icsk->icsk_ack.pingpong)) && 964 !atomic_read(&sk->sk_rmem_alloc))) 965 time_to_ack = 1; 966 } 967 968 /* We send an ACK if we can now advertise a non-zero window 969 * which has been raised "significantly". 970 * 971 * Even if window raised up to infinity, do not send window open ACK 972 * in states, where we will not receive more. It is useless. 973 */ 974 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 975 __u32 rcv_window_now = tcp_receive_window(tp); 976 977 /* Optimize, __tcp_select_window() is not cheap. */ 978 if (2*rcv_window_now <= tp->window_clamp) { 979 __u32 new_window = __tcp_select_window(sk); 980 981 /* Send ACK now, if this read freed lots of space 982 * in our buffer. Certainly, new_window is new window. 983 * We can advertise it now, if it is not less than current one. 984 * "Lots" means "at least twice" here. 985 */ 986 if (new_window && new_window >= 2 * rcv_window_now) 987 time_to_ack = 1; 988 } 989 } 990 if (time_to_ack) 991 tcp_send_ack(sk); 992} 993 994static void tcp_prequeue_process(struct sock *sk) 995{ 996 struct sk_buff *skb; 997 struct tcp_sock *tp = tcp_sk(sk); 998 999 NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED); 1000 1001 /* RX process wants to run with disabled BHs, though it is not 1002 * necessary */ 1003 local_bh_disable(); 1004 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) 1005 sk->sk_backlog_rcv(sk, skb); 1006 local_bh_enable(); 1007 1008 /* Clear memory counter. */ 1009 tp->ucopy.memory = 0; 1010} 1011 1012static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 1013{ 1014 struct sk_buff *skb; 1015 u32 offset; 1016 1017 skb_queue_walk(&sk->sk_receive_queue, skb) { 1018 offset = seq - TCP_SKB_CB(skb)->seq; 1019 if (tcp_hdr(skb)->syn) 1020 offset--; 1021 if (offset < skb->len || tcp_hdr(skb)->fin) { 1022 *off = offset; 1023 return skb; 1024 } 1025 } 1026 return NULL; 1027} 1028 1029/* 1030 * This routine provides an alternative to tcp_recvmsg() for routines 1031 * that would like to handle copying from skbuffs directly in 'sendfile' 1032 * fashion. 1033 * Note: 1034 * - It is assumed that the socket was locked by the caller. 1035 * - The routine does not block. 1036 * - At present, there is no support for reading OOB data 1037 * or for 'peeking' the socket using this routine 1038 * (although both would be easy to implement). 1039 */ 1040int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 1041 sk_read_actor_t recv_actor) 1042{ 1043 struct sk_buff *skb; 1044 struct tcp_sock *tp = tcp_sk(sk); 1045 u32 seq = tp->copied_seq; 1046 u32 offset; 1047 int copied = 0; 1048 1049 if (sk->sk_state == TCP_LISTEN) 1050 return -ENOTCONN; 1051 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { 1052 if (offset < skb->len) { 1053 size_t used, len; 1054 1055 len = skb->len - offset; 1056 /* Stop reading if we hit a patch of urgent data */ 1057 if (tp->urg_data) { 1058 u32 urg_offset = tp->urg_seq - seq; 1059 if (urg_offset < len) 1060 len = urg_offset; 1061 if (!len) 1062 break; 1063 } 1064 used = recv_actor(desc, skb, offset, len); 1065 if (used <= len) { 1066 seq += used; 1067 copied += used; 1068 offset += used; 1069 } 1070 if (offset != skb->len) 1071 break; 1072 } 1073 if (tcp_hdr(skb)->fin) { 1074 sk_eat_skb(sk, skb, 0); 1075 ++seq; 1076 break; 1077 } 1078 sk_eat_skb(sk, skb, 0); 1079 if (!desc->count) 1080 break; 1081 } 1082 tp->copied_seq = seq; 1083 1084 tcp_rcv_space_adjust(sk); 1085 1086 /* Clean up data we have read: This will do ACK frames. */ 1087 if (copied) 1088 tcp_cleanup_rbuf(sk, copied); 1089 return copied; 1090} 1091 1092/* 1093 * This routine copies from a sock struct into the user buffer. 1094 * 1095 * Technical note: in 2.3 we work on _locked_ socket, so that 1096 * tricks with *seq access order and skb->users are not required. 1097 * Probably, code can be easily improved even more. 1098 */ 1099 1100int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 1101 size_t len, int nonblock, int flags, int *addr_len) 1102{ 1103 struct tcp_sock *tp = tcp_sk(sk); 1104 int copied = 0; 1105 u32 peek_seq; 1106 u32 *seq; 1107 unsigned long used; 1108 int err; 1109 int target; /* Read at least this many bytes */ 1110 long timeo; 1111 struct task_struct *user_recv = NULL; 1112 int copied_early = 0; 1113 1114 lock_sock(sk); 1115 1116 TCP_CHECK_TIMER(sk); 1117 1118 err = -ENOTCONN; 1119 if (sk->sk_state == TCP_LISTEN) 1120 goto out; 1121 1122 timeo = sock_rcvtimeo(sk, nonblock); 1123 1124 /* Urgent data needs to be handled specially. */ 1125 if (flags & MSG_OOB) 1126 goto recv_urg; 1127 1128 seq = &tp->copied_seq; 1129 if (flags & MSG_PEEK) { 1130 peek_seq = tp->copied_seq; 1131 seq = &peek_seq; 1132 } 1133 1134 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1135 1136#ifdef CONFIG_NET_DMA 1137 tp->ucopy.dma_chan = NULL; 1138 preempt_disable(); 1139 if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && 1140 !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) { 1141 preempt_enable_no_resched(); 1142 tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len); 1143 } else 1144 preempt_enable_no_resched(); 1145#endif 1146 1147 do { 1148 struct sk_buff *skb; 1149 u32 offset; 1150 1151 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ 1152 if (tp->urg_data && tp->urg_seq == *seq) { 1153 if (copied) 1154 break; 1155 if (signal_pending(current)) { 1156 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; 1157 break; 1158 } 1159 } 1160 1161 /* Next get a buffer. */ 1162 1163 skb = skb_peek(&sk->sk_receive_queue); 1164 do { 1165 if (!skb) 1166 break; 1167 1168 /* Now that we have two receive queues this 1169 * shouldn't happen. 1170 */ 1171 if (before(*seq, TCP_SKB_CB(skb)->seq)) { 1172 printk(KERN_INFO "recvmsg bug: copied %X " 1173 "seq %X\n", *seq, TCP_SKB_CB(skb)->seq); 1174 break; 1175 } 1176 offset = *seq - TCP_SKB_CB(skb)->seq; 1177 if (tcp_hdr(skb)->syn) 1178 offset--; 1179 if (offset < skb->len) 1180 goto found_ok_skb; 1181 if (tcp_hdr(skb)->fin) 1182 goto found_fin_ok; 1183 BUG_TRAP(flags & MSG_PEEK); 1184 skb = skb->next; 1185 } while (skb != (struct sk_buff *)&sk->sk_receive_queue); 1186 1187 /* Well, if we have backlog, try to process it now yet. */ 1188 1189 if (copied >= target && !sk->sk_backlog.tail) 1190 break; 1191 1192 if (copied) { 1193 if (sk->sk_err || 1194 sk->sk_state == TCP_CLOSE || 1195 (sk->sk_shutdown & RCV_SHUTDOWN) || 1196 !timeo || 1197 signal_pending(current) || 1198 (flags & MSG_PEEK)) 1199 break; 1200 } else { 1201 if (sock_flag(sk, SOCK_DONE)) 1202 break; 1203 1204 if (sk->sk_err) { 1205 copied = sock_error(sk); 1206 break; 1207 } 1208 1209 if (sk->sk_shutdown & RCV_SHUTDOWN) 1210 break; 1211 1212 if (sk->sk_state == TCP_CLOSE) { 1213 if (!sock_flag(sk, SOCK_DONE)) { 1214 /* This occurs when user tries to read 1215 * from never connected socket. 1216 */ 1217 copied = -ENOTCONN; 1218 break; 1219 } 1220 break; 1221 } 1222 1223 if (!timeo) { 1224 copied = -EAGAIN; 1225 break; 1226 } 1227 1228 if (signal_pending(current)) { 1229 copied = sock_intr_errno(timeo); 1230 break; 1231 } 1232 } 1233 1234 tcp_cleanup_rbuf(sk, copied); 1235 1236 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1237 /* Install new reader */ 1238 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1239 user_recv = current; 1240 tp->ucopy.task = user_recv; 1241 tp->ucopy.iov = msg->msg_iov; 1242 } 1243 1244 tp->ucopy.len = len; 1245 1246 BUG_TRAP(tp->copied_seq == tp->rcv_nxt || 1247 (flags & (MSG_PEEK | MSG_TRUNC))); 1248 1249 /* Ugly... If prequeue is not empty, we have to 1250 * process it before releasing socket, otherwise 1251 * order will be broken at second iteration. 1252 * More elegant solution is required!!! 1253 * 1254 * Look: we have the following (pseudo)queues: 1255 * 1256 * 1. packets in flight 1257 * 2. backlog 1258 * 3. prequeue 1259 * 4. receive_queue 1260 * 1261 * Each queue can be processed only if the next ones 1262 * are empty. At this point we have empty receive_queue. 1263 * But prequeue _can_ be not empty after 2nd iteration, 1264 * when we jumped to start of loop because backlog 1265 * processing added something to receive_queue. 1266 * We cannot release_sock(), because backlog contains 1267 * packets arrived _after_ prequeued ones. 1268 * 1269 * Shortly, algorithm is clear --- to process all 1270 * the queues in order. We could make it more directly, 1271 * requeueing packets from backlog to prequeue, if 1272 * is not empty. It is more elegant, but eats cycles, 1273 * unfortunately. 1274 */ 1275 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1276 goto do_prequeue; 1277 1278 /* __ Set realtime policy in scheduler __ */ 1279 } 1280 1281 if (copied >= target) { 1282 /* Do not sleep, just process backlog. */ 1283 release_sock(sk); 1284 lock_sock(sk); 1285 } else 1286 sk_wait_data(sk, &timeo); 1287 1288#ifdef CONFIG_NET_DMA 1289 tp->ucopy.wakeup = 0; 1290#endif 1291 1292 if (user_recv) { 1293 int chunk; 1294 1295 /* __ Restore normal policy in scheduler __ */ 1296 1297 if ((chunk = len - tp->ucopy.len) != 0) { 1298 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1299 len -= chunk; 1300 copied += chunk; 1301 } 1302 1303 if (tp->rcv_nxt == tp->copied_seq && 1304 !skb_queue_empty(&tp->ucopy.prequeue)) { 1305do_prequeue: 1306 tcp_prequeue_process(sk); 1307 1308 if ((chunk = len - tp->ucopy.len) != 0) { 1309 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1310 len -= chunk; 1311 copied += chunk; 1312 } 1313 } 1314 } 1315 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) { 1316 if (net_ratelimit()) 1317 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n", 1318 current->comm, current->pid); 1319 peek_seq = tp->copied_seq; 1320 } 1321 continue; 1322 1323 found_ok_skb: 1324 /* Ok so how much can we use? */ 1325 used = skb->len - offset; 1326 if (len < used) 1327 used = len; 1328 1329 /* Do we have urgent data here? */ 1330 if (tp->urg_data) { 1331 u32 urg_offset = tp->urg_seq - *seq; 1332 if (urg_offset < used) { 1333 if (!urg_offset) { 1334 if (!sock_flag(sk, SOCK_URGINLINE)) { 1335 ++*seq; 1336 offset++; 1337 used--; 1338 if (!used) 1339 goto skip_copy; 1340 } 1341 } else 1342 used = urg_offset; 1343 } 1344 } 1345 1346 if (!(flags & MSG_TRUNC)) { 1347#ifdef CONFIG_NET_DMA 1348 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) 1349 tp->ucopy.dma_chan = get_softnet_dma(); 1350 1351 if (tp->ucopy.dma_chan) { 1352 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec( 1353 tp->ucopy.dma_chan, skb, offset, 1354 msg->msg_iov, used, 1355 tp->ucopy.pinned_list); 1356 1357 if (tp->ucopy.dma_cookie < 0) { 1358 1359 printk(KERN_ALERT "dma_cookie < 0\n"); 1360 1361 /* Exception. Bailout! */ 1362 if (!copied) 1363 copied = -EFAULT; 1364 break; 1365 } 1366 if ((offset + used) == skb->len) 1367 copied_early = 1; 1368 1369 } else 1370#endif 1371 { 1372 err = skb_copy_datagram_iovec(skb, offset, 1373 msg->msg_iov, used); 1374 if (err) { 1375 /* Exception. Bailout! */ 1376 if (!copied) 1377 copied = -EFAULT; 1378 break; 1379 } 1380 } 1381 } 1382 1383 *seq += used; 1384 copied += used; 1385 len -= used; 1386 1387 tcp_rcv_space_adjust(sk); 1388 1389skip_copy: 1390 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1391 tp->urg_data = 0; 1392 tcp_fast_path_check(sk, tp); 1393 } 1394 if (used + offset < skb->len) 1395 continue; 1396 1397 if (tcp_hdr(skb)->fin) 1398 goto found_fin_ok; 1399 if (!(flags & MSG_PEEK)) { 1400 sk_eat_skb(sk, skb, copied_early); 1401 copied_early = 0; 1402 } 1403 continue; 1404 1405 found_fin_ok: 1406 /* Process the FIN. */ 1407 ++*seq; 1408 if (!(flags & MSG_PEEK)) { 1409 sk_eat_skb(sk, skb, copied_early); 1410 copied_early = 0; 1411 } 1412 break; 1413 } while (len > 0); 1414 1415 if (user_recv) { 1416 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1417 int chunk; 1418 1419 tp->ucopy.len = copied > 0 ? len : 0; 1420 1421 tcp_prequeue_process(sk); 1422 1423 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1424 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1425 len -= chunk; 1426 copied += chunk; 1427 } 1428 } 1429 1430 tp->ucopy.task = NULL; 1431 tp->ucopy.len = 0; 1432 } 1433 1434#ifdef CONFIG_NET_DMA 1435 if (tp->ucopy.dma_chan) { 1436 struct sk_buff *skb; 1437 dma_cookie_t done, used; 1438 1439 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1440 1441 while (dma_async_memcpy_complete(tp->ucopy.dma_chan, 1442 tp->ucopy.dma_cookie, &done, 1443 &used) == DMA_IN_PROGRESS) { 1444 /* do partial cleanup of sk_async_wait_queue */ 1445 while ((skb = skb_peek(&sk->sk_async_wait_queue)) && 1446 (dma_async_is_complete(skb->dma_cookie, done, 1447 used) == DMA_SUCCESS)) { 1448 __skb_dequeue(&sk->sk_async_wait_queue); 1449 kfree_skb(skb); 1450 } 1451 } 1452 1453 /* Safe to free early-copied skbs now */ 1454 __skb_queue_purge(&sk->sk_async_wait_queue); 1455 dma_chan_put(tp->ucopy.dma_chan); 1456 tp->ucopy.dma_chan = NULL; 1457 } 1458 if (tp->ucopy.pinned_list) { 1459 dma_unpin_iovec_pages(tp->ucopy.pinned_list); 1460 tp->ucopy.pinned_list = NULL; 1461 } 1462#endif 1463 1464 /* According to UNIX98, msg_name/msg_namelen are ignored 1465 * on connected socket. I was just happy when found this 8) --ANK 1466 */ 1467 1468 /* Clean up data we have read: This will do ACK frames. */ 1469 tcp_cleanup_rbuf(sk, copied); 1470 1471 TCP_CHECK_TIMER(sk); 1472 release_sock(sk); 1473 return copied; 1474 1475out: 1476 TCP_CHECK_TIMER(sk); 1477 release_sock(sk); 1478 return err; 1479 1480recv_urg: 1481 err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len); 1482 goto out; 1483} 1484 1485/* 1486 * State processing on a close. This implements the state shift for 1487 * sending our FIN frame. Note that we only send a FIN for some 1488 * states. A shutdown() may have already sent the FIN, or we may be 1489 * closed. 1490 */ 1491 1492static const unsigned char new_state[16] = { 1493 /* current state: new state: action: */ 1494 /* (Invalid) */ TCP_CLOSE, 1495 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1496 /* TCP_SYN_SENT */ TCP_CLOSE, 1497 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1498 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, 1499 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, 1500 /* TCP_TIME_WAIT */ TCP_CLOSE, 1501 /* TCP_CLOSE */ TCP_CLOSE, 1502 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, 1503 /* TCP_LAST_ACK */ TCP_LAST_ACK, 1504 /* TCP_LISTEN */ TCP_CLOSE, 1505 /* TCP_CLOSING */ TCP_CLOSING, 1506}; 1507 1508static int tcp_close_state(struct sock *sk) 1509{ 1510 int next = (int)new_state[sk->sk_state]; 1511 int ns = next & TCP_STATE_MASK; 1512 1513 tcp_set_state(sk, ns); 1514 1515 return next & TCP_ACTION_FIN; 1516} 1517 1518/* 1519 * Shutdown the sending side of a connection. Much like close except 1520 * that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD). 1521 */ 1522 1523void tcp_shutdown(struct sock *sk, int how) 1524{ 1525 /* We need to grab some memory, and put together a FIN, 1526 * and then put it into the queue to be sent. 1527 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 1528 */ 1529 if (!(how & SEND_SHUTDOWN)) 1530 return; 1531 1532 /* If we've already sent a FIN, or it's a closed state, skip this. */ 1533 if ((1 << sk->sk_state) & 1534 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 1535 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 1536 /* Clear out any half completed packets. FIN if needed. */ 1537 if (tcp_close_state(sk)) 1538 tcp_send_fin(sk); 1539 } 1540} 1541 1542void tcp_close(struct sock *sk, long timeout) 1543{ 1544 struct sk_buff *skb; 1545 int data_was_unread = 0; 1546 int state; 1547 1548 lock_sock(sk); 1549 sk->sk_shutdown = SHUTDOWN_MASK; 1550 1551 if (sk->sk_state == TCP_LISTEN) { 1552 tcp_set_state(sk, TCP_CLOSE); 1553 1554 /* Special case. */ 1555 inet_csk_listen_stop(sk); 1556 1557 goto adjudge_to_death; 1558 } 1559 1560 /* We need to flush the recv. buffs. We do this only on the 1561 * descriptor close, not protocol-sourced closes, because the 1562 * reader process may not have drained the data yet! 1563 */ 1564 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 1565 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq - 1566 tcp_hdr(skb)->fin; 1567 data_was_unread += len; 1568 __kfree_skb(skb); 1569 } 1570 1571 sk_stream_mem_reclaim(sk); 1572 1573 /* As outlined in draft-ietf-tcpimpl-prob-03.txt, section 1574 * 3.10, we send a RST here because data was lost. To 1575 * witness the awful effects of the old behavior of always 1576 * doing a FIN, run an older 2.1.x kernel or 2.0.x, start 1577 * a bulk GET in an FTP client, suspend the process, wait 1578 * for the client to advertise a zero window, then kill -9 1579 * the FTP client, wheee... Note: timeout is always zero 1580 * in such a case. 1581 */ 1582 if (data_was_unread) { 1583 /* Unread data was tossed, zap the connection. */ 1584 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE); 1585 tcp_set_state(sk, TCP_CLOSE); 1586 tcp_send_active_reset(sk, GFP_KERNEL); 1587 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 1588 /* Check zero linger _after_ checking for unread data. */ 1589 sk->sk_prot->disconnect(sk, 0); 1590 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA); 1591 } else if (tcp_close_state(sk)) { 1592 /* We FIN if the application ate all the data before 1593 * zapping the connection. 1594 */ 1595 1596 /* RED-PEN. Formally speaking, we have broken TCP state 1597 * machine. State transitions: 1598 * 1599 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 1600 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 1601 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 1602 * 1603 * are legal only when FIN has been sent (i.e. in window), 1604 * rather than queued out of window. Purists blame. 1605 * 1606 * F.e. "RFC state" is ESTABLISHED, 1607 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 1608 * 1609 * The visible declinations are that sometimes 1610 * we enter time-wait state, when it is not required really 1611 * (harmless), do not send active resets, when they are 1612 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 1613 * they look as CLOSING or LAST_ACK for Linux) 1614 * Probably, I missed some more holelets. 1615 * --ANK 1616 */ 1617 tcp_send_fin(sk); 1618 } 1619 1620 sk_stream_wait_close(sk, timeout); 1621 1622adjudge_to_death: 1623 state = sk->sk_state; 1624 sock_hold(sk); 1625 sock_orphan(sk); 1626 atomic_inc(sk->sk_prot->orphan_count); 1627 1628 /* It is the last release_sock in its life. It will remove backlog. */ 1629 release_sock(sk); 1630 1631 1632 /* Now socket is owned by kernel and we acquire BH lock 1633 to finish close. No need to check for user refs. 1634 */ 1635 local_bh_disable(); 1636 bh_lock_sock(sk); 1637 BUG_TRAP(!sock_owned_by_user(sk)); 1638 1639 /* Have we already been destroyed by a softirq or backlog? */ 1640 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) 1641 goto out; 1642 1643 /* This is a (useful) BSD violating of the RFC. There is a 1644 * problem with TCP as specified in that the other end could 1645 * keep a socket open forever with no application left this end. 1646 * We use a 3 minute timeout (about the same as BSD) then kill 1647 * our end. If they send after that then tough - BUT: long enough 1648 * that we won't make the old 4*rto = almost no time - whoops 1649 * reset mistake. 1650 * 1651 * Nope, it was not mistake. It is really desired behaviour 1652 * f.e. on http servers, when such sockets are useless, but 1653 * consume significant resources. Let's do it with special 1654 * linger2 option. --ANK 1655 */ 1656 1657 if (sk->sk_state == TCP_FIN_WAIT2) { 1658 struct tcp_sock *tp = tcp_sk(sk); 1659 if (tp->linger2 < 0) { 1660 tcp_set_state(sk, TCP_CLOSE); 1661 tcp_send_active_reset(sk, GFP_ATOMIC); 1662 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER); 1663 } else { 1664 const int tmo = tcp_fin_time(sk); 1665 1666 if (tmo > TCP_TIMEWAIT_LEN) { 1667 inet_csk_reset_keepalive_timer(sk, 1668 tmo - TCP_TIMEWAIT_LEN); 1669 } else { 1670 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); 1671 goto out; 1672 } 1673 } 1674 } 1675 if (sk->sk_state != TCP_CLOSE) { 1676 sk_stream_mem_reclaim(sk); 1677 if (atomic_read(sk->sk_prot->orphan_count) > sysctl_tcp_max_orphans || 1678 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 1679 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) { 1680 if (net_ratelimit()) 1681 printk(KERN_INFO "TCP: too many of orphaned " 1682 "sockets\n"); 1683 tcp_set_state(sk, TCP_CLOSE); 1684 tcp_send_active_reset(sk, GFP_ATOMIC); 1685 NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY); 1686 } 1687 } 1688 1689 if (sk->sk_state == TCP_CLOSE) 1690 inet_csk_destroy_sock(sk); 1691 /* Otherwise, socket is reprieved until protocol close. */ 1692 1693out: 1694 bh_unlock_sock(sk); 1695 local_bh_enable(); 1696 sock_put(sk); 1697} 1698 1699/* These states need RST on ABORT according to RFC793 */ 1700 1701static inline int tcp_need_reset(int state) 1702{ 1703 return (1 << state) & 1704 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 1705 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 1706} 1707 1708int tcp_disconnect(struct sock *sk, int flags) 1709{ 1710 struct inet_sock *inet = inet_sk(sk); 1711 struct inet_connection_sock *icsk = inet_csk(sk); 1712 struct tcp_sock *tp = tcp_sk(sk); 1713 int err = 0; 1714 int old_state = sk->sk_state; 1715 1716 if (old_state != TCP_CLOSE) 1717 tcp_set_state(sk, TCP_CLOSE); 1718 1719 /* ABORT function of RFC793 */ 1720 if (old_state == TCP_LISTEN) { 1721 inet_csk_listen_stop(sk); 1722 } else if (tcp_need_reset(old_state) || 1723 (tp->snd_nxt != tp->write_seq && 1724 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 1725 /* The last check adjusts for discrepancy of Linux wrt. RFC 1726 * states 1727 */ 1728 tcp_send_active_reset(sk, gfp_any()); 1729 sk->sk_err = ECONNRESET; 1730 } else if (old_state == TCP_SYN_SENT) 1731 sk->sk_err = ECONNRESET; 1732 1733 tcp_clear_xmit_timers(sk); 1734 __skb_queue_purge(&sk->sk_receive_queue); 1735 tcp_write_queue_purge(sk); 1736 __skb_queue_purge(&tp->out_of_order_queue); 1737#ifdef CONFIG_NET_DMA 1738 __skb_queue_purge(&sk->sk_async_wait_queue); 1739#endif 1740 1741 inet->dport = 0; 1742 1743 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 1744 inet_reset_saddr(sk); 1745 1746 sk->sk_shutdown = 0; 1747 sock_reset_flag(sk, SOCK_DONE); 1748 tp->srtt = 0; 1749 if ((tp->write_seq += tp->max_window + 2) == 0) 1750 tp->write_seq = 1; 1751 icsk->icsk_backoff = 0; 1752 tp->snd_cwnd = 2; 1753 icsk->icsk_probes_out = 0; 1754 tp->packets_out = 0; 1755 tp->snd_ssthresh = 0x7fffffff; 1756 tp->snd_cwnd_cnt = 0; 1757 tp->bytes_acked = 0; 1758 tcp_set_ca_state(sk, TCP_CA_Open); 1759 tcp_clear_retrans(tp); 1760 inet_csk_delack_init(sk); 1761 tcp_init_send_head(sk); 1762 tp->rx_opt.saw_tstamp = 0; 1763 tcp_sack_reset(&tp->rx_opt); 1764 __sk_dst_reset(sk); 1765 1766 BUG_TRAP(!inet->num || icsk->icsk_bind_hash); 1767 1768 sk->sk_error_report(sk); 1769 return err; 1770} 1771 1772/* 1773 * Socket option code for TCP. 1774 */ 1775static int do_tcp_setsockopt(struct sock *sk, int level, 1776 int optname, char __user *optval, int optlen) 1777{ 1778 struct tcp_sock *tp = tcp_sk(sk); 1779 struct inet_connection_sock *icsk = inet_csk(sk); 1780 int val; 1781 int err = 0; 1782 1783 /* This is a string value all the others are int's */ 1784 if (optname == TCP_CONGESTION) { 1785 char name[TCP_CA_NAME_MAX]; 1786 1787 if (optlen < 1) 1788 return -EINVAL; 1789 1790 val = strncpy_from_user(name, optval, 1791 min(TCP_CA_NAME_MAX-1, optlen)); 1792 if (val < 0) 1793 return -EFAULT; 1794 name[val] = 0; 1795 1796 lock_sock(sk); 1797 err = tcp_set_congestion_control(sk, name); 1798 release_sock(sk); 1799 return err; 1800 } 1801 1802 if (optlen < sizeof(int)) 1803 return -EINVAL; 1804 1805 if (get_user(val, (int __user *)optval)) 1806 return -EFAULT; 1807 1808 lock_sock(sk); 1809 1810 switch (optname) { 1811 case TCP_MAXSEG: 1812 /* Values greater than interface MTU won't take effect. However 1813 * at the point when this call is done we typically don't yet 1814 * know which interface is going to be used */ 1815 if (val < 8 || val > MAX_TCP_WINDOW) { 1816 err = -EINVAL; 1817 break; 1818 } 1819 tp->rx_opt.user_mss = val; 1820 break; 1821 1822 case TCP_NODELAY: 1823 if (val) { 1824 /* TCP_NODELAY is weaker than TCP_CORK, so that 1825 * this option on corked socket is remembered, but 1826 * it is not activated until cork is cleared. 1827 * 1828 * However, when TCP_NODELAY is set we make 1829 * an explicit push, which overrides even TCP_CORK 1830 * for currently queued segments. 1831 */ 1832 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 1833 tcp_push_pending_frames(sk, tp); 1834 } else { 1835 tp->nonagle &= ~TCP_NAGLE_OFF; 1836 } 1837 break; 1838 1839 case TCP_CORK: 1840 /* When set indicates to always queue non-full frames. 1841 * Later the user clears this option and we transmit 1842 * any pending partial frames in the queue. This is 1843 * meant to be used alongside sendfile() to get properly 1844 * filled frames when the user (for example) must write 1845 * out headers with a write() call first and then use 1846 * sendfile to send out the data parts. 1847 * 1848 * TCP_CORK can be set together with TCP_NODELAY and it is 1849 * stronger than TCP_NODELAY. 1850 */ 1851 if (val) { 1852 tp->nonagle |= TCP_NAGLE_CORK; 1853 } else { 1854 tp->nonagle &= ~TCP_NAGLE_CORK; 1855 if (tp->nonagle&TCP_NAGLE_OFF) 1856 tp->nonagle |= TCP_NAGLE_PUSH; 1857 tcp_push_pending_frames(sk, tp); 1858 } 1859 break; 1860 1861 case TCP_KEEPIDLE: 1862 if (val < 1 || val > MAX_TCP_KEEPIDLE) 1863 err = -EINVAL; 1864 else { 1865 tp->keepalive_time = val * HZ; 1866 if (sock_flag(sk, SOCK_KEEPOPEN) && 1867 !((1 << sk->sk_state) & 1868 (TCPF_CLOSE | TCPF_LISTEN))) { 1869 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp; 1870 if (tp->keepalive_time > elapsed) 1871 elapsed = tp->keepalive_time - elapsed; 1872 else 1873 elapsed = 0; 1874 inet_csk_reset_keepalive_timer(sk, elapsed); 1875 } 1876 } 1877 break; 1878 case TCP_KEEPINTVL: 1879 if (val < 1 || val > MAX_TCP_KEEPINTVL) 1880 err = -EINVAL; 1881 else 1882 tp->keepalive_intvl = val * HZ; 1883 break; 1884 case TCP_KEEPCNT: 1885 if (val < 1 || val > MAX_TCP_KEEPCNT) 1886 err = -EINVAL; 1887 else 1888 tp->keepalive_probes = val; 1889 break; 1890 case TCP_SYNCNT: 1891 if (val < 1 || val > MAX_TCP_SYNCNT) 1892 err = -EINVAL; 1893 else 1894 icsk->icsk_syn_retries = val; 1895 break; 1896 1897 case TCP_LINGER2: 1898 if (val < 0) 1899 tp->linger2 = -1; 1900 else if (val > sysctl_tcp_fin_timeout / HZ) 1901 tp->linger2 = 0; 1902 else 1903 tp->linger2 = val * HZ; 1904 break; 1905 1906 case TCP_DEFER_ACCEPT: 1907 icsk->icsk_accept_queue.rskq_defer_accept = 0; 1908 if (val > 0) { 1909 /* Translate value in seconds to number of 1910 * retransmits */ 1911 while (icsk->icsk_accept_queue.rskq_defer_accept < 32 && 1912 val > ((TCP_TIMEOUT_INIT / HZ) << 1913 icsk->icsk_accept_queue.rskq_defer_accept)) 1914 icsk->icsk_accept_queue.rskq_defer_accept++; 1915 icsk->icsk_accept_queue.rskq_defer_accept++; 1916 } 1917 break; 1918 1919 case TCP_WINDOW_CLAMP: 1920 if (!val) { 1921 if (sk->sk_state != TCP_CLOSE) { 1922 err = -EINVAL; 1923 break; 1924 } 1925 tp->window_clamp = 0; 1926 } else 1927 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 1928 SOCK_MIN_RCVBUF / 2 : val; 1929 break; 1930 1931 case TCP_QUICKACK: 1932 if (!val) { 1933 icsk->icsk_ack.pingpong = 1; 1934 } else { 1935 icsk->icsk_ack.pingpong = 0; 1936 if ((1 << sk->sk_state) & 1937 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 1938 inet_csk_ack_scheduled(sk)) { 1939 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 1940 tcp_cleanup_rbuf(sk, 1); 1941 if (!(val & 1)) 1942 icsk->icsk_ack.pingpong = 1; 1943 } 1944 } 1945 break; 1946 1947#ifdef CONFIG_TCP_MD5SIG 1948 case TCP_MD5SIG: 1949 /* Read the IP->Key mappings from userspace */ 1950 err = tp->af_specific->md5_parse(sk, optval, optlen); 1951 break; 1952#endif 1953 1954 default: 1955 err = -ENOPROTOOPT; 1956 break; 1957 } 1958 1959 release_sock(sk); 1960 return err; 1961} 1962 1963int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 1964 int optlen) 1965{ 1966 struct inet_connection_sock *icsk = inet_csk(sk); 1967 1968 if (level != SOL_TCP) 1969 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 1970 optval, optlen); 1971 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 1972} 1973 1974#ifdef CONFIG_COMPAT 1975int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 1976 char __user *optval, int optlen) 1977{ 1978 if (level != SOL_TCP) 1979 return inet_csk_compat_setsockopt(sk, level, optname, 1980 optval, optlen); 1981 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 1982} 1983 1984EXPORT_SYMBOL(compat_tcp_setsockopt); 1985#endif 1986 1987/* Return information about state of tcp endpoint in API format. */ 1988void tcp_get_info(struct sock *sk, struct tcp_info *info) 1989{ 1990 struct tcp_sock *tp = tcp_sk(sk); 1991 const struct inet_connection_sock *icsk = inet_csk(sk); 1992 u32 now = tcp_time_stamp; 1993 1994 memset(info, 0, sizeof(*info)); 1995 1996 info->tcpi_state = sk->sk_state; 1997 info->tcpi_ca_state = icsk->icsk_ca_state; 1998 info->tcpi_retransmits = icsk->icsk_retransmits; 1999 info->tcpi_probes = icsk->icsk_probes_out; 2000 info->tcpi_backoff = icsk->icsk_backoff; 2001 2002 if (tp->rx_opt.tstamp_ok) 2003 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2004 if (tp->rx_opt.sack_ok) 2005 info->tcpi_options |= TCPI_OPT_SACK; 2006 if (tp->rx_opt.wscale_ok) { 2007 info->tcpi_options |= TCPI_OPT_WSCALE; 2008 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2009 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2010 } 2011 2012 if (tp->ecn_flags&TCP_ECN_OK) 2013 info->tcpi_options |= TCPI_OPT_ECN; 2014 2015 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2016 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2017 info->tcpi_snd_mss = tp->mss_cache; 2018 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2019 2020 info->tcpi_unacked = tp->packets_out; 2021 info->tcpi_sacked = tp->sacked_out; 2022 info->tcpi_lost = tp->lost_out; 2023 info->tcpi_retrans = tp->retrans_out; 2024 info->tcpi_fackets = tp->fackets_out; 2025 2026 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2027 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2028 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2029 2030 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2031 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2032 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3; 2033 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2; 2034 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2035 info->tcpi_snd_cwnd = tp->snd_cwnd; 2036 info->tcpi_advmss = tp->advmss; 2037 info->tcpi_reordering = tp->reordering; 2038 2039 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2040 info->tcpi_rcv_space = tp->rcvq_space.space; 2041 2042 info->tcpi_total_retrans = tp->total_retrans; 2043} 2044 2045EXPORT_SYMBOL_GPL(tcp_get_info); 2046 2047static int do_tcp_getsockopt(struct sock *sk, int level, 2048 int optname, char __user *optval, int __user *optlen) 2049{ 2050 struct inet_connection_sock *icsk = inet_csk(sk); 2051 struct tcp_sock *tp = tcp_sk(sk); 2052 int val, len; 2053 2054 if (get_user(len, optlen)) 2055 return -EFAULT; 2056 2057 len = min_t(unsigned int, len, sizeof(int)); 2058 2059 if (len < 0) 2060 return -EINVAL; 2061 2062 switch (optname) { 2063 case TCP_MAXSEG: 2064 val = tp->mss_cache; 2065 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2066 val = tp->rx_opt.user_mss; 2067 break; 2068 case TCP_NODELAY: 2069 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2070 break; 2071 case TCP_CORK: 2072 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2073 break; 2074 case TCP_KEEPIDLE: 2075 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ; 2076 break; 2077 case TCP_KEEPINTVL: 2078 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ; 2079 break; 2080 case TCP_KEEPCNT: 2081 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes; 2082 break; 2083 case TCP_SYNCNT: 2084 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2085 break; 2086 case TCP_LINGER2: 2087 val = tp->linger2; 2088 if (val >= 0) 2089 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2090 break; 2091 case TCP_DEFER_ACCEPT: 2092 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 : 2093 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1)); 2094 break; 2095 case TCP_WINDOW_CLAMP: 2096 val = tp->window_clamp; 2097 break; 2098 case TCP_INFO: { 2099 struct tcp_info info; 2100 2101 if (get_user(len, optlen)) 2102 return -EFAULT; 2103 2104 tcp_get_info(sk, &info); 2105 2106 len = min_t(unsigned int, len, sizeof(info)); 2107 if (put_user(len, optlen)) 2108 return -EFAULT; 2109 if (copy_to_user(optval, &info, len)) 2110 return -EFAULT; 2111 return 0; 2112 } 2113 case TCP_QUICKACK: 2114 val = !icsk->icsk_ack.pingpong; 2115 break; 2116 2117 case TCP_CONGESTION: 2118 if (get_user(len, optlen)) 2119 return -EFAULT; 2120 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2121 if (put_user(len, optlen)) 2122 return -EFAULT; 2123 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2124 return -EFAULT; 2125 return 0; 2126 default: 2127 return -ENOPROTOOPT; 2128 } 2129 2130 if (put_user(len, optlen)) 2131 return -EFAULT; 2132 if (copy_to_user(optval, &val, len)) 2133 return -EFAULT; 2134 return 0; 2135} 2136 2137int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2138 int __user *optlen) 2139{ 2140 struct inet_connection_sock *icsk = inet_csk(sk); 2141 2142 if (level != SOL_TCP) 2143 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2144 optval, optlen); 2145 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2146} 2147 2148#ifdef CONFIG_COMPAT 2149int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2150 char __user *optval, int __user *optlen) 2151{ 2152 if (level != SOL_TCP) 2153 return inet_csk_compat_getsockopt(sk, level, optname, 2154 optval, optlen); 2155 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2156} 2157 2158EXPORT_SYMBOL(compat_tcp_getsockopt); 2159#endif 2160 2161struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features) 2162{ 2163 struct sk_buff *segs = ERR_PTR(-EINVAL); 2164 struct tcphdr *th; 2165 unsigned thlen; 2166 unsigned int seq; 2167 __be32 delta; 2168 unsigned int oldlen; 2169 unsigned int len; 2170 2171 if (!pskb_may_pull(skb, sizeof(*th))) 2172 goto out; 2173 2174 th = tcp_hdr(skb); 2175 thlen = th->doff * 4; 2176 if (thlen < sizeof(*th)) 2177 goto out; 2178 2179 if (!pskb_may_pull(skb, thlen)) 2180 goto out; 2181 2182 oldlen = (u16)~skb->len; 2183 __skb_pull(skb, thlen); 2184 2185 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 2186 /* Packet is from an untrusted source, reset gso_segs. */ 2187 int type = skb_shinfo(skb)->gso_type; 2188 int mss; 2189 2190 if (unlikely(type & 2191 ~(SKB_GSO_TCPV4 | 2192 SKB_GSO_DODGY | 2193 SKB_GSO_TCP_ECN | 2194 SKB_GSO_TCPV6 | 2195 0) || 2196 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) 2197 goto out; 2198 2199 mss = skb_shinfo(skb)->gso_size; 2200 skb_shinfo(skb)->gso_segs = (skb->len + mss - 1) / mss; 2201 2202 segs = NULL; 2203 goto out; 2204 } 2205 2206 segs = skb_segment(skb, features); 2207 if (IS_ERR(segs)) 2208 goto out; 2209 2210 len = skb_shinfo(skb)->gso_size; 2211 delta = htonl(oldlen + (thlen + len)); 2212 2213 skb = segs; 2214 th = tcp_hdr(skb); 2215 seq = ntohl(th->seq); 2216 2217 do { 2218 th->fin = th->psh = 0; 2219 2220 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2221 (__force u32)delta)); 2222 if (skb->ip_summed != CHECKSUM_PARTIAL) 2223 th->check = 2224 csum_fold(csum_partial(skb_transport_header(skb), 2225 thlen, skb->csum)); 2226 2227 seq += len; 2228 skb = skb->next; 2229 th = tcp_hdr(skb); 2230 2231 th->seq = htonl(seq); 2232 th->cwr = 0; 2233 } while (skb->next); 2234 2235 delta = htonl(oldlen + (skb->tail - skb->transport_header) + 2236 skb->data_len); 2237 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2238 (__force u32)delta)); 2239 if (skb->ip_summed != CHECKSUM_PARTIAL) 2240 th->check = csum_fold(csum_partial(skb_transport_header(skb), 2241 thlen, skb->csum)); 2242 2243out: 2244 return segs; 2245} 2246EXPORT_SYMBOL(tcp_tso_segment); 2247 2248#ifdef CONFIG_TCP_MD5SIG 2249static unsigned long tcp_md5sig_users; 2250static struct tcp_md5sig_pool **tcp_md5sig_pool; 2251static DEFINE_SPINLOCK(tcp_md5sig_pool_lock); 2252 2253static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool) 2254{ 2255 int cpu; 2256 for_each_possible_cpu(cpu) { 2257 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu); 2258 if (p) { 2259 if (p->md5_desc.tfm) 2260 crypto_free_hash(p->md5_desc.tfm); 2261 kfree(p); 2262 p = NULL; 2263 } 2264 } 2265 free_percpu(pool); 2266} 2267 2268void tcp_free_md5sig_pool(void) 2269{ 2270 struct tcp_md5sig_pool **pool = NULL; 2271 2272 spin_lock_bh(&tcp_md5sig_pool_lock); 2273 if (--tcp_md5sig_users == 0) { 2274 pool = tcp_md5sig_pool; 2275 tcp_md5sig_pool = NULL; 2276 } 2277 spin_unlock_bh(&tcp_md5sig_pool_lock); 2278 if (pool) 2279 __tcp_free_md5sig_pool(pool); 2280} 2281 2282EXPORT_SYMBOL(tcp_free_md5sig_pool); 2283 2284static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void) 2285{ 2286 int cpu; 2287 struct tcp_md5sig_pool **pool; 2288 2289 pool = alloc_percpu(struct tcp_md5sig_pool *); 2290 if (!pool) 2291 return NULL; 2292 2293 for_each_possible_cpu(cpu) { 2294 struct tcp_md5sig_pool *p; 2295 struct crypto_hash *hash; 2296 2297 p = kzalloc(sizeof(*p), GFP_KERNEL); 2298 if (!p) 2299 goto out_free; 2300 *per_cpu_ptr(pool, cpu) = p; 2301 2302 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 2303 if (!hash || IS_ERR(hash)) 2304 goto out_free; 2305 2306 p->md5_desc.tfm = hash; 2307 } 2308 return pool; 2309out_free: 2310 __tcp_free_md5sig_pool(pool); 2311 return NULL; 2312} 2313 2314struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void) 2315{ 2316 struct tcp_md5sig_pool **pool; 2317 int alloc = 0; 2318 2319retry: 2320 spin_lock_bh(&tcp_md5sig_pool_lock); 2321 pool = tcp_md5sig_pool; 2322 if (tcp_md5sig_users++ == 0) { 2323 alloc = 1; 2324 spin_unlock_bh(&tcp_md5sig_pool_lock); 2325 } else if (!pool) { 2326 tcp_md5sig_users--; 2327 spin_unlock_bh(&tcp_md5sig_pool_lock); 2328 cpu_relax(); 2329 goto retry; 2330 } else 2331 spin_unlock_bh(&tcp_md5sig_pool_lock); 2332 2333 if (alloc) { 2334 /* we cannot hold spinlock here because this may sleep. */ 2335 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool(); 2336 spin_lock_bh(&tcp_md5sig_pool_lock); 2337 if (!p) { 2338 tcp_md5sig_users--; 2339 spin_unlock_bh(&tcp_md5sig_pool_lock); 2340 return NULL; 2341 } 2342 pool = tcp_md5sig_pool; 2343 if (pool) { 2344 /* oops, it has already been assigned. */ 2345 spin_unlock_bh(&tcp_md5sig_pool_lock); 2346 __tcp_free_md5sig_pool(p); 2347 } else { 2348 tcp_md5sig_pool = pool = p; 2349 spin_unlock_bh(&tcp_md5sig_pool_lock); 2350 } 2351 } 2352 return pool; 2353} 2354 2355EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 2356 2357struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu) 2358{ 2359 struct tcp_md5sig_pool **p; 2360 spin_lock_bh(&tcp_md5sig_pool_lock); 2361 p = tcp_md5sig_pool; 2362 if (p) 2363 tcp_md5sig_users++; 2364 spin_unlock_bh(&tcp_md5sig_pool_lock); 2365 return (p ? *per_cpu_ptr(p, cpu) : NULL); 2366} 2367 2368EXPORT_SYMBOL(__tcp_get_md5sig_pool); 2369 2370void __tcp_put_md5sig_pool(void) 2371{ 2372 tcp_free_md5sig_pool(); 2373} 2374 2375EXPORT_SYMBOL(__tcp_put_md5sig_pool); 2376#endif 2377 2378extern void __skb_cb_too_small_for_tcp(int, int); 2379extern struct tcp_congestion_ops tcp_reno; 2380 2381static __initdata unsigned long thash_entries; 2382static int __init set_thash_entries(char *str) 2383{ 2384 if (!str) 2385 return 0; 2386 thash_entries = simple_strtoul(str, &str, 0); 2387 return 1; 2388} 2389__setup("thash_entries=", set_thash_entries); 2390 2391void __init tcp_init(void) 2392{ 2393 struct sk_buff *skb = NULL; 2394 unsigned long limit; 2395 int order, i, max_share; 2396 2397 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb)) 2398 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb), 2399 sizeof(skb->cb)); 2400 2401 tcp_hashinfo.bind_bucket_cachep = 2402 kmem_cache_create("tcp_bind_bucket", 2403 sizeof(struct inet_bind_bucket), 0, 2404 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); 2405 2406 /* Size and allocate the main established and bind bucket 2407 * hash tables. 2408 * 2409 * The methodology is similar to that of the buffer cache. 2410 */ 2411 tcp_hashinfo.ehash = 2412 alloc_large_system_hash("TCP established", 2413 sizeof(struct inet_ehash_bucket), 2414 thash_entries, 2415 (num_physpages >= 128 * 1024) ? 2416 13 : 15, 2417 0, 2418 &tcp_hashinfo.ehash_size, 2419 NULL, 2420 0); 2421 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size; 2422 for (i = 0; i < tcp_hashinfo.ehash_size; i++) { 2423 rwlock_init(&tcp_hashinfo.ehash[i].lock); 2424 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain); 2425 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain); 2426 } 2427 2428 tcp_hashinfo.bhash = 2429 alloc_large_system_hash("TCP bind", 2430 sizeof(struct inet_bind_hashbucket), 2431 tcp_hashinfo.ehash_size, 2432 (num_physpages >= 128 * 1024) ? 2433 13 : 15, 2434 0, 2435 &tcp_hashinfo.bhash_size, 2436 NULL, 2437 64 * 1024); 2438 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size; 2439 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 2440 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 2441 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 2442 } 2443 2444 /* Try to be a bit smarter and adjust defaults depending 2445 * on available memory. 2446 */ 2447 for (order = 0; ((1 << order) << PAGE_SHIFT) < 2448 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket)); 2449 order++) 2450 ; 2451 if (order >= 4) { 2452 sysctl_local_port_range[0] = 32768; 2453 sysctl_local_port_range[1] = 61000; 2454 tcp_death_row.sysctl_max_tw_buckets = 180000; 2455 sysctl_tcp_max_orphans = 4096 << (order - 4); 2456 sysctl_max_syn_backlog = 1024; 2457 } else if (order < 3) { 2458 sysctl_local_port_range[0] = 1024 * (3 - order); 2459 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order); 2460 sysctl_tcp_max_orphans >>= (3 - order); 2461 sysctl_max_syn_backlog = 128; 2462 } 2463 2464 /* Set the pressure threshold to be a fraction of global memory that 2465 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of 2466 * memory, with a floor of 128 pages. 2467 */ 2468 limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); 2469 limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); 2470 limit = max(limit, 128UL); 2471 sysctl_tcp_mem[0] = limit / 4 * 3; 2472 sysctl_tcp_mem[1] = limit; 2473 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; 2474 2475 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 2476 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7); 2477 max_share = min(4UL*1024*1024, limit); 2478 2479 sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM; 2480 sysctl_tcp_wmem[1] = 16*1024; 2481 sysctl_tcp_wmem[2] = max(64*1024, max_share); 2482 2483 sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM; 2484 sysctl_tcp_rmem[1] = 87380; 2485 sysctl_tcp_rmem[2] = max(87380, max_share); 2486 2487 printk(KERN_INFO "TCP: Hash tables configured " 2488 "(established %d bind %d)\n", 2489 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size); 2490 2491 tcp_register_congestion_control(&tcp_reno); 2492} 2493 2494EXPORT_SYMBOL(tcp_close); 2495EXPORT_SYMBOL(tcp_disconnect); 2496EXPORT_SYMBOL(tcp_getsockopt); 2497EXPORT_SYMBOL(tcp_ioctl); 2498EXPORT_SYMBOL(tcp_poll); 2499EXPORT_SYMBOL(tcp_read_sock); 2500EXPORT_SYMBOL(tcp_recvmsg); 2501EXPORT_SYMBOL(tcp_sendmsg); 2502EXPORT_SYMBOL(tcp_sendpage); 2503EXPORT_SYMBOL(tcp_setsockopt); 2504EXPORT_SYMBOL(tcp_shutdown); 2505EXPORT_SYMBOL(tcp_statistics); 2506