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> 271 272 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 273 274 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly; 275 276 atomic_t tcp_orphan_count = ATOMIC_INIT(0); 277 278 EXPORT_SYMBOL_GPL(tcp_orphan_count); 279 280 int sysctl_tcp_mem[3] __read_mostly; 281 int sysctl_tcp_wmem[3] __read_mostly; 282 int sysctl_tcp_rmem[3] __read_mostly; 283 284 EXPORT_SYMBOL(sysctl_tcp_mem); 285 EXPORT_SYMBOL(sysctl_tcp_rmem); 286 EXPORT_SYMBOL(sysctl_tcp_wmem); 287 288 atomic_t tcp_memory_allocated; /* Current allocated memory. */ 289 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */ 290 291 EXPORT_SYMBOL(tcp_memory_allocated); 292 EXPORT_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 */ 300 int tcp_memory_pressure; 301 302 EXPORT_SYMBOL(tcp_memory_pressure); 303 304 void 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 } 311 312 EXPORT_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 */ 321 unsigned 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 } 405 406 int 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 ((struct sk_buff *)sk->sk_receive_queue.prev)->h.th->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 } 451 452 static 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 } 457 458 static inline int forced_push(struct tcp_sock *tp) 459 { 460 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 461 } 462 463 static 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 __skb_queue_tail(&sk->sk_write_queue, skb); 474 sk_charge_skb(sk, skb); 475 if (!sk->sk_send_head) 476 sk->sk_send_head = skb; 477 if (tp->nonagle & TCP_NAGLE_PUSH) 478 tp->nonagle &= ~TCP_NAGLE_PUSH; 479 } 480 481 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags, 482 struct sk_buff *skb) 483 { 484 if (flags & MSG_OOB) { 485 tp->urg_mode = 1; 486 tp->snd_up = tp->write_seq; 487 TCP_SKB_CB(skb)->sacked |= TCPCB_URG; 488 } 489 } 490 491 static inline void tcp_push(struct sock *sk, struct tcp_sock *tp, int flags, 492 int mss_now, int nonagle) 493 { 494 if (sk->sk_send_head) { 495 struct sk_buff *skb = sk->sk_write_queue.prev; 496 if (!(flags & MSG_MORE) || forced_push(tp)) 497 tcp_mark_push(tp, skb); 498 tcp_mark_urg(tp, flags, skb); 499 __tcp_push_pending_frames(sk, tp, mss_now, 500 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle); 501 } 502 } 503 504 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, 505 size_t psize, int flags) 506 { 507 struct tcp_sock *tp = tcp_sk(sk); 508 int mss_now, size_goal; 509 int err; 510 ssize_t copied; 511 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 512 513 /* Wait for a connection to finish. */ 514 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 515 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 516 goto out_err; 517 518 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 519 520 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 521 size_goal = tp->xmit_size_goal; 522 copied = 0; 523 524 err = -EPIPE; 525 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 526 goto do_error; 527 528 while (psize > 0) { 529 struct sk_buff *skb = sk->sk_write_queue.prev; 530 struct page *page = pages[poffset / PAGE_SIZE]; 531 int copy, i, can_coalesce; 532 int offset = poffset % PAGE_SIZE; 533 int size = min_t(size_t, psize, PAGE_SIZE - offset); 534 535 if (!sk->sk_send_head || (copy = size_goal - skb->len) <= 0) { 536 new_segment: 537 if (!sk_stream_memory_free(sk)) 538 goto wait_for_sndbuf; 539 540 skb = sk_stream_alloc_pskb(sk, 0, 0, 541 sk->sk_allocation); 542 if (!skb) 543 goto wait_for_memory; 544 545 skb_entail(sk, tp, skb); 546 copy = size_goal; 547 } 548 549 if (copy > size) 550 copy = size; 551 552 i = skb_shinfo(skb)->nr_frags; 553 can_coalesce = skb_can_coalesce(skb, i, page, offset); 554 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 555 tcp_mark_push(tp, skb); 556 goto new_segment; 557 } 558 if (!sk_stream_wmem_schedule(sk, copy)) 559 goto wait_for_memory; 560 561 if (can_coalesce) { 562 skb_shinfo(skb)->frags[i - 1].size += copy; 563 } else { 564 get_page(page); 565 skb_fill_page_desc(skb, i, page, offset, copy); 566 } 567 568 skb->len += copy; 569 skb->data_len += copy; 570 skb->truesize += copy; 571 sk->sk_wmem_queued += copy; 572 sk->sk_forward_alloc -= copy; 573 skb->ip_summed = CHECKSUM_PARTIAL; 574 tp->write_seq += copy; 575 TCP_SKB_CB(skb)->end_seq += copy; 576 skb_shinfo(skb)->gso_segs = 0; 577 578 if (!copied) 579 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH; 580 581 copied += copy; 582 poffset += copy; 583 if (!(psize -= copy)) 584 goto out; 585 586 if (skb->len < mss_now || (flags & MSG_OOB)) 587 continue; 588 589 if (forced_push(tp)) { 590 tcp_mark_push(tp, skb); 591 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH); 592 } else if (skb == sk->sk_send_head) 593 tcp_push_one(sk, mss_now); 594 continue; 595 596 wait_for_sndbuf: 597 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 598 wait_for_memory: 599 if (copied) 600 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 601 602 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 603 goto do_error; 604 605 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 606 size_goal = tp->xmit_size_goal; 607 } 608 609 out: 610 if (copied) 611 tcp_push(sk, tp, flags, mss_now, tp->nonagle); 612 return copied; 613 614 do_error: 615 if (copied) 616 goto out; 617 out_err: 618 return sk_stream_error(sk, flags, err); 619 } 620 621 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, 622 size_t size, int flags) 623 { 624 ssize_t res; 625 struct sock *sk = sock->sk; 626 627 if (!(sk->sk_route_caps & NETIF_F_SG) || 628 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 629 return sock_no_sendpage(sock, page, offset, size, flags); 630 631 lock_sock(sk); 632 TCP_CHECK_TIMER(sk); 633 res = do_tcp_sendpages(sk, &page, offset, size, flags); 634 TCP_CHECK_TIMER(sk); 635 release_sock(sk); 636 return res; 637 } 638 639 #define TCP_PAGE(sk) (sk->sk_sndmsg_page) 640 #define TCP_OFF(sk) (sk->sk_sndmsg_off) 641 642 static inline int select_size(struct sock *sk, struct tcp_sock *tp) 643 { 644 int tmp = tp->mss_cache; 645 646 if (sk->sk_route_caps & NETIF_F_SG) { 647 if (sk_can_gso(sk)) 648 tmp = 0; 649 else { 650 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 651 652 if (tmp >= pgbreak && 653 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 654 tmp = pgbreak; 655 } 656 } 657 658 return tmp; 659 } 660 661 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 662 size_t size) 663 { 664 struct iovec *iov; 665 struct tcp_sock *tp = tcp_sk(sk); 666 struct sk_buff *skb; 667 int iovlen, flags; 668 int mss_now, size_goal; 669 int err, copied; 670 long timeo; 671 672 lock_sock(sk); 673 TCP_CHECK_TIMER(sk); 674 675 flags = msg->msg_flags; 676 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 677 678 /* Wait for a connection to finish. */ 679 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 680 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 681 goto out_err; 682 683 /* This should be in poll */ 684 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 685 686 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 687 size_goal = tp->xmit_size_goal; 688 689 /* Ok commence sending. */ 690 iovlen = msg->msg_iovlen; 691 iov = msg->msg_iov; 692 copied = 0; 693 694 err = -EPIPE; 695 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 696 goto do_error; 697 698 while (--iovlen >= 0) { 699 int seglen = iov->iov_len; 700 unsigned char __user *from = iov->iov_base; 701 702 iov++; 703 704 while (seglen > 0) { 705 int copy; 706 707 skb = sk->sk_write_queue.prev; 708 709 if (!sk->sk_send_head || 710 (copy = size_goal - skb->len) <= 0) { 711 712 new_segment: 713 /* Allocate new segment. If the interface is SG, 714 * allocate skb fitting to single page. 715 */ 716 if (!sk_stream_memory_free(sk)) 717 goto wait_for_sndbuf; 718 719 skb = sk_stream_alloc_pskb(sk, select_size(sk, tp), 720 0, sk->sk_allocation); 721 if (!skb) 722 goto wait_for_memory; 723 724 /* 725 * Check whether we can use HW checksum. 726 */ 727 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 728 skb->ip_summed = CHECKSUM_PARTIAL; 729 730 skb_entail(sk, tp, skb); 731 copy = size_goal; 732 } 733 734 /* Try to append data to the end of skb. */ 735 if (copy > seglen) 736 copy = seglen; 737 738 /* Where to copy to? */ 739 if (skb_tailroom(skb) > 0) { 740 /* We have some space in skb head. Superb! */ 741 if (copy > skb_tailroom(skb)) 742 copy = skb_tailroom(skb); 743 if ((err = skb_add_data(skb, from, copy)) != 0) 744 goto do_fault; 745 } else { 746 int merge = 0; 747 int i = skb_shinfo(skb)->nr_frags; 748 struct page *page = TCP_PAGE(sk); 749 int off = TCP_OFF(sk); 750 751 if (skb_can_coalesce(skb, i, page, off) && 752 off != PAGE_SIZE) { 753 /* We can extend the last page 754 * fragment. */ 755 merge = 1; 756 } else if (i == MAX_SKB_FRAGS || 757 (!i && 758 !(sk->sk_route_caps & NETIF_F_SG))) { 759 /* Need to add new fragment and cannot 760 * do this because interface is non-SG, 761 * or because all the page slots are 762 * busy. */ 763 tcp_mark_push(tp, skb); 764 goto new_segment; 765 } else if (page) { 766 if (off == PAGE_SIZE) { 767 put_page(page); 768 TCP_PAGE(sk) = page = NULL; 769 off = 0; 770 } 771 } else 772 off = 0; 773 774 if (copy > PAGE_SIZE - off) 775 copy = PAGE_SIZE - off; 776 777 if (!sk_stream_wmem_schedule(sk, copy)) 778 goto wait_for_memory; 779 780 if (!page) { 781 /* Allocate new cache page. */ 782 if (!(page = sk_stream_alloc_page(sk))) 783 goto wait_for_memory; 784 } 785 786 /* Time to copy data. We are close to 787 * the end! */ 788 err = skb_copy_to_page(sk, from, skb, page, 789 off, copy); 790 if (err) { 791 /* If this page was new, give it to the 792 * socket so it does not get leaked. 793 */ 794 if (!TCP_PAGE(sk)) { 795 TCP_PAGE(sk) = page; 796 TCP_OFF(sk) = 0; 797 } 798 goto do_error; 799 } 800 801 /* Update the skb. */ 802 if (merge) { 803 skb_shinfo(skb)->frags[i - 1].size += 804 copy; 805 } else { 806 skb_fill_page_desc(skb, i, page, off, copy); 807 if (TCP_PAGE(sk)) { 808 get_page(page); 809 } else if (off + copy < PAGE_SIZE) { 810 get_page(page); 811 TCP_PAGE(sk) = page; 812 } 813 } 814 815 TCP_OFF(sk) = off + copy; 816 } 817 818 if (!copied) 819 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH; 820 821 tp->write_seq += copy; 822 TCP_SKB_CB(skb)->end_seq += copy; 823 skb_shinfo(skb)->gso_segs = 0; 824 825 from += copy; 826 copied += copy; 827 if ((seglen -= copy) == 0 && iovlen == 0) 828 goto out; 829 830 if (skb->len < mss_now || (flags & MSG_OOB)) 831 continue; 832 833 if (forced_push(tp)) { 834 tcp_mark_push(tp, skb); 835 __tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH); 836 } else if (skb == sk->sk_send_head) 837 tcp_push_one(sk, mss_now); 838 continue; 839 840 wait_for_sndbuf: 841 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 842 wait_for_memory: 843 if (copied) 844 tcp_push(sk, tp, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 845 846 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 847 goto do_error; 848 849 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); 850 size_goal = tp->xmit_size_goal; 851 } 852 } 853 854 out: 855 if (copied) 856 tcp_push(sk, tp, flags, mss_now, tp->nonagle); 857 TCP_CHECK_TIMER(sk); 858 release_sock(sk); 859 return copied; 860 861 do_fault: 862 if (!skb->len) { 863 if (sk->sk_send_head == skb) 864 sk->sk_send_head = NULL; 865 __skb_unlink(skb, &sk->sk_write_queue); 866 sk_stream_free_skb(sk, skb); 867 } 868 869 do_error: 870 if (copied) 871 goto out; 872 out_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 */ 883 884 static 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 */ 936 void 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 } 993 994 static 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 1012 static 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 (skb->h.th->syn) 1020 offset--; 1021 if (offset < skb->len || skb->h.th->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 */ 1040 int 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 (skb->h.th->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 1100 int 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 (skb->h.th->syn) 1178 offset--; 1179 if (offset < skb->len) 1180 goto found_ok_skb; 1181 if (skb->h.th->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)) { 1305 do_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 1389 skip_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 (skb->h.th->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 1475 out: 1476 TCP_CHECK_TIMER(sk); 1477 release_sock(sk); 1478 return err; 1479 1480 recv_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 1492 static const unsigned char new_state[16] = { 1493 /* current state: new state: action: */ 1494 /* (Invalid) */ TCP_CLOSE, 1495 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1496 /* TCP_SYN_SENT */ TCP_CLOSE, 1497 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1498 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, 1499 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, 1500 /* TCP_TIME_WAIT */ TCP_CLOSE, 1501 /* TCP_CLOSE */ TCP_CLOSE, 1502 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, 1503 /* TCP_LAST_ACK */ TCP_LAST_ACK, 1504 /* TCP_LISTEN */ TCP_CLOSE, 1505 /* TCP_CLOSING */ TCP_CLOSING, 1506 }; 1507 1508 static 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 1523 void 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 1542 void 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 skb->h.th->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 1622 adjudge_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 1693 out: 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 1701 static 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 1708 int 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 sk_stream_writequeue_purge(sk); 1736 __skb_queue_purge(&tp->out_of_order_queue); 1737 #ifdef CONFIG_NET_DMA 1738 __skb_queue_purge(&sk->sk_async_wait_queue); 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 sk->sk_send_head = NULL; 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 */ 1775 static 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 release_sock(sk); 1959 return err; 1960 } 1961 1962 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 1963 int optlen) 1964 { 1965 struct inet_connection_sock *icsk = inet_csk(sk); 1966 1967 if (level != SOL_TCP) 1968 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 1969 optval, optlen); 1970 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 1971 } 1972 1973 #ifdef CONFIG_COMPAT 1974 int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 1975 char __user *optval, int optlen) 1976 { 1977 if (level != SOL_TCP) 1978 return inet_csk_compat_setsockopt(sk, level, optname, 1979 optval, optlen); 1980 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 1981 } 1982 1983 EXPORT_SYMBOL(compat_tcp_setsockopt); 1984 #endif 1985 1986 /* Return information about state of tcp endpoint in API format. */ 1987 void tcp_get_info(struct sock *sk, struct tcp_info *info) 1988 { 1989 struct tcp_sock *tp = tcp_sk(sk); 1990 const struct inet_connection_sock *icsk = inet_csk(sk); 1991 u32 now = tcp_time_stamp; 1992 1993 memset(info, 0, sizeof(*info)); 1994 1995 info->tcpi_state = sk->sk_state; 1996 info->tcpi_ca_state = icsk->icsk_ca_state; 1997 info->tcpi_retransmits = icsk->icsk_retransmits; 1998 info->tcpi_probes = icsk->icsk_probes_out; 1999 info->tcpi_backoff = icsk->icsk_backoff; 2000 2001 if (tp->rx_opt.tstamp_ok) 2002 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2003 if (tp->rx_opt.sack_ok) 2004 info->tcpi_options |= TCPI_OPT_SACK; 2005 if (tp->rx_opt.wscale_ok) { 2006 info->tcpi_options |= TCPI_OPT_WSCALE; 2007 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2008 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2009 } 2010 2011 if (tp->ecn_flags&TCP_ECN_OK) 2012 info->tcpi_options |= TCPI_OPT_ECN; 2013 2014 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2015 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2016 info->tcpi_snd_mss = tp->mss_cache; 2017 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2018 2019 info->tcpi_unacked = tp->packets_out; 2020 info->tcpi_sacked = tp->sacked_out; 2021 info->tcpi_lost = tp->lost_out; 2022 info->tcpi_retrans = tp->retrans_out; 2023 info->tcpi_fackets = tp->fackets_out; 2024 2025 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2026 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2027 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2028 2029 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2030 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2031 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3; 2032 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2; 2033 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2034 info->tcpi_snd_cwnd = tp->snd_cwnd; 2035 info->tcpi_advmss = tp->advmss; 2036 info->tcpi_reordering = tp->reordering; 2037 2038 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2039 info->tcpi_rcv_space = tp->rcvq_space.space; 2040 2041 info->tcpi_total_retrans = tp->total_retrans; 2042 } 2043 2044 EXPORT_SYMBOL_GPL(tcp_get_info); 2045 2046 static int do_tcp_getsockopt(struct sock *sk, int level, 2047 int optname, char __user *optval, int __user *optlen) 2048 { 2049 struct inet_connection_sock *icsk = inet_csk(sk); 2050 struct tcp_sock *tp = tcp_sk(sk); 2051 int val, len; 2052 2053 if (get_user(len, optlen)) 2054 return -EFAULT; 2055 2056 len = min_t(unsigned int, len, sizeof(int)); 2057 2058 if (len < 0) 2059 return -EINVAL; 2060 2061 switch (optname) { 2062 case TCP_MAXSEG: 2063 val = tp->mss_cache; 2064 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2065 val = tp->rx_opt.user_mss; 2066 break; 2067 case TCP_NODELAY: 2068 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2069 break; 2070 case TCP_CORK: 2071 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2072 break; 2073 case TCP_KEEPIDLE: 2074 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ; 2075 break; 2076 case TCP_KEEPINTVL: 2077 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ; 2078 break; 2079 case TCP_KEEPCNT: 2080 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes; 2081 break; 2082 case TCP_SYNCNT: 2083 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2084 break; 2085 case TCP_LINGER2: 2086 val = tp->linger2; 2087 if (val >= 0) 2088 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2089 break; 2090 case TCP_DEFER_ACCEPT: 2091 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 : 2092 ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1)); 2093 break; 2094 case TCP_WINDOW_CLAMP: 2095 val = tp->window_clamp; 2096 break; 2097 case TCP_INFO: { 2098 struct tcp_info info; 2099 2100 if (get_user(len, optlen)) 2101 return -EFAULT; 2102 2103 tcp_get_info(sk, &info); 2104 2105 len = min_t(unsigned int, len, sizeof(info)); 2106 if (put_user(len, optlen)) 2107 return -EFAULT; 2108 if (copy_to_user(optval, &info, len)) 2109 return -EFAULT; 2110 return 0; 2111 } 2112 case TCP_QUICKACK: 2113 val = !icsk->icsk_ack.pingpong; 2114 break; 2115 2116 case TCP_CONGESTION: 2117 if (get_user(len, optlen)) 2118 return -EFAULT; 2119 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2120 if (put_user(len, optlen)) 2121 return -EFAULT; 2122 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2123 return -EFAULT; 2124 return 0; 2125 default: 2126 return -ENOPROTOOPT; 2127 }; 2128 2129 if (put_user(len, optlen)) 2130 return -EFAULT; 2131 if (copy_to_user(optval, &val, len)) 2132 return -EFAULT; 2133 return 0; 2134 } 2135 2136 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2137 int __user *optlen) 2138 { 2139 struct inet_connection_sock *icsk = inet_csk(sk); 2140 2141 if (level != SOL_TCP) 2142 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2143 optval, optlen); 2144 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2145 } 2146 2147 #ifdef CONFIG_COMPAT 2148 int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2149 char __user *optval, int __user *optlen) 2150 { 2151 if (level != SOL_TCP) 2152 return inet_csk_compat_getsockopt(sk, level, optname, 2153 optval, optlen); 2154 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2155 } 2156 2157 EXPORT_SYMBOL(compat_tcp_getsockopt); 2158 #endif 2159 2160 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features) 2161 { 2162 struct sk_buff *segs = ERR_PTR(-EINVAL); 2163 struct tcphdr *th; 2164 unsigned thlen; 2165 unsigned int seq; 2166 __be32 delta; 2167 unsigned int oldlen; 2168 unsigned int len; 2169 2170 if (!pskb_may_pull(skb, sizeof(*th))) 2171 goto out; 2172 2173 th = skb->h.th; 2174 thlen = th->doff * 4; 2175 if (thlen < sizeof(*th)) 2176 goto out; 2177 2178 if (!pskb_may_pull(skb, thlen)) 2179 goto out; 2180 2181 oldlen = (u16)~skb->len; 2182 __skb_pull(skb, thlen); 2183 2184 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 2185 /* Packet is from an untrusted source, reset gso_segs. */ 2186 int type = skb_shinfo(skb)->gso_type; 2187 int mss; 2188 2189 if (unlikely(type & 2190 ~(SKB_GSO_TCPV4 | 2191 SKB_GSO_DODGY | 2192 SKB_GSO_TCP_ECN | 2193 SKB_GSO_TCPV6 | 2194 0) || 2195 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) 2196 goto out; 2197 2198 mss = skb_shinfo(skb)->gso_size; 2199 skb_shinfo(skb)->gso_segs = (skb->len + mss - 1) / mss; 2200 2201 segs = NULL; 2202 goto out; 2203 } 2204 2205 segs = skb_segment(skb, features); 2206 if (IS_ERR(segs)) 2207 goto out; 2208 2209 len = skb_shinfo(skb)->gso_size; 2210 delta = htonl(oldlen + (thlen + len)); 2211 2212 skb = segs; 2213 th = skb->h.th; 2214 seq = ntohl(th->seq); 2215 2216 do { 2217 th->fin = th->psh = 0; 2218 2219 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2220 (__force u32)delta)); 2221 if (skb->ip_summed != CHECKSUM_PARTIAL) 2222 th->check = csum_fold(csum_partial(skb->h.raw, thlen, 2223 skb->csum)); 2224 2225 seq += len; 2226 skb = skb->next; 2227 th = skb->h.th; 2228 2229 th->seq = htonl(seq); 2230 th->cwr = 0; 2231 } while (skb->next); 2232 2233 delta = htonl(oldlen + (skb->tail - skb->h.raw) + skb->data_len); 2234 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2235 (__force u32)delta)); 2236 if (skb->ip_summed != CHECKSUM_PARTIAL) 2237 th->check = csum_fold(csum_partial(skb->h.raw, thlen, 2238 skb->csum)); 2239 2240 out: 2241 return segs; 2242 } 2243 EXPORT_SYMBOL(tcp_tso_segment); 2244 2245 #ifdef CONFIG_TCP_MD5SIG 2246 static unsigned long tcp_md5sig_users; 2247 static struct tcp_md5sig_pool **tcp_md5sig_pool; 2248 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock); 2249 2250 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool) 2251 { 2252 int cpu; 2253 for_each_possible_cpu(cpu) { 2254 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu); 2255 if (p) { 2256 if (p->md5_desc.tfm) 2257 crypto_free_hash(p->md5_desc.tfm); 2258 kfree(p); 2259 p = NULL; 2260 } 2261 } 2262 free_percpu(pool); 2263 } 2264 2265 void tcp_free_md5sig_pool(void) 2266 { 2267 struct tcp_md5sig_pool **pool = NULL; 2268 2269 spin_lock_bh(&tcp_md5sig_pool_lock); 2270 if (--tcp_md5sig_users == 0) { 2271 pool = tcp_md5sig_pool; 2272 tcp_md5sig_pool = NULL; 2273 } 2274 spin_unlock_bh(&tcp_md5sig_pool_lock); 2275 if (pool) 2276 __tcp_free_md5sig_pool(pool); 2277 } 2278 2279 EXPORT_SYMBOL(tcp_free_md5sig_pool); 2280 2281 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void) 2282 { 2283 int cpu; 2284 struct tcp_md5sig_pool **pool; 2285 2286 pool = alloc_percpu(struct tcp_md5sig_pool *); 2287 if (!pool) 2288 return NULL; 2289 2290 for_each_possible_cpu(cpu) { 2291 struct tcp_md5sig_pool *p; 2292 struct crypto_hash *hash; 2293 2294 p = kzalloc(sizeof(*p), GFP_KERNEL); 2295 if (!p) 2296 goto out_free; 2297 *per_cpu_ptr(pool, cpu) = p; 2298 2299 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 2300 if (!hash || IS_ERR(hash)) 2301 goto out_free; 2302 2303 p->md5_desc.tfm = hash; 2304 } 2305 return pool; 2306 out_free: 2307 __tcp_free_md5sig_pool(pool); 2308 return NULL; 2309 } 2310 2311 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void) 2312 { 2313 struct tcp_md5sig_pool **pool; 2314 int alloc = 0; 2315 2316 retry: 2317 spin_lock_bh(&tcp_md5sig_pool_lock); 2318 pool = tcp_md5sig_pool; 2319 if (tcp_md5sig_users++ == 0) { 2320 alloc = 1; 2321 spin_unlock_bh(&tcp_md5sig_pool_lock); 2322 } else if (!pool) { 2323 tcp_md5sig_users--; 2324 spin_unlock_bh(&tcp_md5sig_pool_lock); 2325 cpu_relax(); 2326 goto retry; 2327 } else 2328 spin_unlock_bh(&tcp_md5sig_pool_lock); 2329 2330 if (alloc) { 2331 /* we cannot hold spinlock here because this may sleep. */ 2332 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool(); 2333 spin_lock_bh(&tcp_md5sig_pool_lock); 2334 if (!p) { 2335 tcp_md5sig_users--; 2336 spin_unlock_bh(&tcp_md5sig_pool_lock); 2337 return NULL; 2338 } 2339 pool = tcp_md5sig_pool; 2340 if (pool) { 2341 /* oops, it has already been assigned. */ 2342 spin_unlock_bh(&tcp_md5sig_pool_lock); 2343 __tcp_free_md5sig_pool(p); 2344 } else { 2345 tcp_md5sig_pool = pool = p; 2346 spin_unlock_bh(&tcp_md5sig_pool_lock); 2347 } 2348 } 2349 return pool; 2350 } 2351 2352 EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 2353 2354 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu) 2355 { 2356 struct tcp_md5sig_pool **p; 2357 spin_lock_bh(&tcp_md5sig_pool_lock); 2358 p = tcp_md5sig_pool; 2359 if (p) 2360 tcp_md5sig_users++; 2361 spin_unlock_bh(&tcp_md5sig_pool_lock); 2362 return (p ? *per_cpu_ptr(p, cpu) : NULL); 2363 } 2364 2365 EXPORT_SYMBOL(__tcp_get_md5sig_pool); 2366 2367 void __tcp_put_md5sig_pool(void) 2368 { 2369 tcp_free_md5sig_pool(); 2370 } 2371 2372 EXPORT_SYMBOL(__tcp_put_md5sig_pool); 2373 #endif 2374 2375 extern void __skb_cb_too_small_for_tcp(int, int); 2376 extern struct tcp_congestion_ops tcp_reno; 2377 2378 static __initdata unsigned long thash_entries; 2379 static int __init set_thash_entries(char *str) 2380 { 2381 if (!str) 2382 return 0; 2383 thash_entries = simple_strtoul(str, &str, 0); 2384 return 1; 2385 } 2386 __setup("thash_entries=", set_thash_entries); 2387 2388 void __init tcp_init(void) 2389 { 2390 struct sk_buff *skb = NULL; 2391 unsigned long limit; 2392 int order, i, max_share; 2393 2394 if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb)) 2395 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb), 2396 sizeof(skb->cb)); 2397 2398 tcp_hashinfo.bind_bucket_cachep = 2399 kmem_cache_create("tcp_bind_bucket", 2400 sizeof(struct inet_bind_bucket), 0, 2401 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); 2402 2403 /* Size and allocate the main established and bind bucket 2404 * hash tables. 2405 * 2406 * The methodology is similar to that of the buffer cache. 2407 */ 2408 tcp_hashinfo.ehash = 2409 alloc_large_system_hash("TCP established", 2410 sizeof(struct inet_ehash_bucket), 2411 thash_entries, 2412 (num_physpages >= 128 * 1024) ? 2413 13 : 15, 2414 0, 2415 &tcp_hashinfo.ehash_size, 2416 NULL, 2417 0); 2418 tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size; 2419 for (i = 0; i < tcp_hashinfo.ehash_size; i++) { 2420 rwlock_init(&tcp_hashinfo.ehash[i].lock); 2421 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain); 2422 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain); 2423 } 2424 2425 tcp_hashinfo.bhash = 2426 alloc_large_system_hash("TCP bind", 2427 sizeof(struct inet_bind_hashbucket), 2428 tcp_hashinfo.ehash_size, 2429 (num_physpages >= 128 * 1024) ? 2430 13 : 15, 2431 0, 2432 &tcp_hashinfo.bhash_size, 2433 NULL, 2434 64 * 1024); 2435 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size; 2436 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 2437 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 2438 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 2439 } 2440 2441 /* Try to be a bit smarter and adjust defaults depending 2442 * on available memory. 2443 */ 2444 for (order = 0; ((1 << order) << PAGE_SHIFT) < 2445 (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket)); 2446 order++) 2447 ; 2448 if (order >= 4) { 2449 sysctl_local_port_range[0] = 32768; 2450 sysctl_local_port_range[1] = 61000; 2451 tcp_death_row.sysctl_max_tw_buckets = 180000; 2452 sysctl_tcp_max_orphans = 4096 << (order - 4); 2453 sysctl_max_syn_backlog = 1024; 2454 } else if (order < 3) { 2455 sysctl_local_port_range[0] = 1024 * (3 - order); 2456 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order); 2457 sysctl_tcp_max_orphans >>= (3 - order); 2458 sysctl_max_syn_backlog = 128; 2459 } 2460 2461 /* Set the pressure threshold to be a fraction of global memory that 2462 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of 2463 * memory, with a floor of 128 pages. 2464 */ 2465 limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); 2466 limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); 2467 limit = max(limit, 128UL); 2468 sysctl_tcp_mem[0] = limit / 4 * 3; 2469 sysctl_tcp_mem[1] = limit; 2470 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; 2471 2472 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 2473 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7); 2474 max_share = min(4UL*1024*1024, limit); 2475 2476 sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM; 2477 sysctl_tcp_wmem[1] = 16*1024; 2478 sysctl_tcp_wmem[2] = max(64*1024, max_share); 2479 2480 sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM; 2481 sysctl_tcp_rmem[1] = 87380; 2482 sysctl_tcp_rmem[2] = max(87380, max_share); 2483 2484 printk(KERN_INFO "TCP: Hash tables configured " 2485 "(established %d bind %d)\n", 2486 tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size); 2487 2488 tcp_register_congestion_control(&tcp_reno); 2489 } 2490 2491 EXPORT_SYMBOL(tcp_close); 2492 EXPORT_SYMBOL(tcp_disconnect); 2493 EXPORT_SYMBOL(tcp_getsockopt); 2494 EXPORT_SYMBOL(tcp_ioctl); 2495 EXPORT_SYMBOL(tcp_poll); 2496 EXPORT_SYMBOL(tcp_read_sock); 2497 EXPORT_SYMBOL(tcp_recvmsg); 2498 EXPORT_SYMBOL(tcp_sendmsg); 2499 EXPORT_SYMBOL(tcp_sendpage); 2500 EXPORT_SYMBOL(tcp_setsockopt); 2501 EXPORT_SYMBOL(tcp_shutdown); 2502 EXPORT_SYMBOL(tcp_statistics); 2503