1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * Implementation of the Transmission Control Protocol(TCP). 7 * 8 * Authors: Ross Biro 9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 10 * Mark Evans, <evansmp@uhura.aston.ac.uk> 11 * Corey Minyard <wf-rch!minyard@relay.EU.net> 12 * Florian La Roche, <flla@stud.uni-sb.de> 13 * Charles Hedrick, <hedrick@klinzhai.rutgers.edu> 14 * Linus Torvalds, <torvalds@cs.helsinki.fi> 15 * Alan Cox, <gw4pts@gw4pts.ampr.org> 16 * Matthew Dillon, <dillon@apollo.west.oic.com> 17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 18 * Jorge Cwik, <jorge@laser.satlink.net> 19 * 20 * Fixes: 21 * Alan Cox : Numerous verify_area() calls 22 * Alan Cox : Set the ACK bit on a reset 23 * Alan Cox : Stopped it crashing if it closed while 24 * sk->inuse=1 and was trying to connect 25 * (tcp_err()). 26 * Alan Cox : All icmp error handling was broken 27 * pointers passed where wrong and the 28 * socket was looked up backwards. Nobody 29 * tested any icmp error code obviously. 30 * Alan Cox : tcp_err() now handled properly. It 31 * wakes people on errors. poll 32 * behaves and the icmp error race 33 * has gone by moving it into sock.c 34 * Alan Cox : tcp_send_reset() fixed to work for 35 * everything not just packets for 36 * unknown sockets. 37 * Alan Cox : tcp option processing. 38 * Alan Cox : Reset tweaked (still not 100%) [Had 39 * syn rule wrong] 40 * Herp Rosmanith : More reset fixes 41 * Alan Cox : No longer acks invalid rst frames. 42 * Acking any kind of RST is right out. 43 * Alan Cox : Sets an ignore me flag on an rst 44 * receive otherwise odd bits of prattle 45 * escape still 46 * Alan Cox : Fixed another acking RST frame bug. 47 * Should stop LAN workplace lockups. 48 * Alan Cox : Some tidyups using the new skb list 49 * facilities 50 * Alan Cox : sk->keepopen now seems to work 51 * Alan Cox : Pulls options out correctly on accepts 52 * Alan Cox : Fixed assorted sk->rqueue->next errors 53 * Alan Cox : PSH doesn't end a TCP read. Switched a 54 * bit to skb ops. 55 * Alan Cox : Tidied tcp_data to avoid a potential 56 * nasty. 57 * Alan Cox : Added some better commenting, as the 58 * tcp is hard to follow 59 * Alan Cox : Removed incorrect check for 20 * psh 60 * Michael O'Reilly : ack < copied bug fix. 61 * Johannes Stille : Misc tcp fixes (not all in yet). 62 * Alan Cox : FIN with no memory -> CRASH 63 * Alan Cox : Added socket option proto entries. 64 * Also added awareness of them to accept. 65 * Alan Cox : Added TCP options (SOL_TCP) 66 * Alan Cox : Switched wakeup calls to callbacks, 67 * so the kernel can layer network 68 * sockets. 69 * Alan Cox : Use ip_tos/ip_ttl settings. 70 * Alan Cox : Handle FIN (more) properly (we hope). 71 * Alan Cox : RST frames sent on unsynchronised 72 * state ack error. 73 * Alan Cox : Put in missing check for SYN bit. 74 * Alan Cox : Added tcp_select_window() aka NET2E 75 * window non shrink trick. 76 * Alan Cox : Added a couple of small NET2E timer 77 * fixes 78 * Charles Hedrick : TCP fixes 79 * Toomas Tamm : TCP window fixes 80 * Alan Cox : Small URG fix to rlogin ^C ack fight 81 * Charles Hedrick : Rewrote most of it to actually work 82 * Linus : Rewrote tcp_read() and URG handling 83 * completely 84 * Gerhard Koerting: Fixed some missing timer handling 85 * Matthew Dillon : Reworked TCP machine states as per RFC 86 * Gerhard Koerting: PC/TCP workarounds 87 * Adam Caldwell : Assorted timer/timing errors 88 * Matthew Dillon : Fixed another RST bug 89 * Alan Cox : Move to kernel side addressing changes. 90 * Alan Cox : Beginning work on TCP fastpathing 91 * (not yet usable) 92 * Arnt Gulbrandsen: Turbocharged tcp_check() routine. 93 * Alan Cox : TCP fast path debugging 94 * Alan Cox : Window clamping 95 * Michael Riepe : Bug in tcp_check() 96 * Matt Dillon : More TCP improvements and RST bug fixes 97 * Matt Dillon : Yet more small nasties remove from the 98 * TCP code (Be very nice to this man if 99 * tcp finally works 100%) 8) 100 * Alan Cox : BSD accept semantics. 101 * Alan Cox : Reset on closedown bug. 102 * Peter De Schrijver : ENOTCONN check missing in tcp_sendto(). 103 * Michael Pall : Handle poll() after URG properly in 104 * all cases. 105 * Michael Pall : Undo the last fix in tcp_read_urg() 106 * (multi URG PUSH broke rlogin). 107 * Michael Pall : Fix the multi URG PUSH problem in 108 * tcp_readable(), poll() after URG 109 * works now. 110 * Michael Pall : recv(...,MSG_OOB) never blocks in the 111 * BSD api. 112 * Alan Cox : Changed the semantics of sk->socket to 113 * fix a race and a signal problem with 114 * accept() and async I/O. 115 * Alan Cox : Relaxed the rules on tcp_sendto(). 116 * Yury Shevchuk : Really fixed accept() blocking problem. 117 * Craig I. Hagan : Allow for BSD compatible TIME_WAIT for 118 * clients/servers which listen in on 119 * fixed ports. 120 * Alan Cox : Cleaned the above up and shrank it to 121 * a sensible code size. 122 * Alan Cox : Self connect lockup fix. 123 * Alan Cox : No connect to multicast. 124 * Ross Biro : Close unaccepted children on master 125 * socket close. 126 * Alan Cox : Reset tracing code. 127 * Alan Cox : Spurious resets on shutdown. 128 * Alan Cox : Giant 15 minute/60 second timer error 129 * Alan Cox : Small whoops in polling before an 130 * accept. 131 * Alan Cox : Kept the state trace facility since 132 * it's handy for debugging. 133 * Alan Cox : More reset handler fixes. 134 * Alan Cox : Started rewriting the code based on 135 * the RFC's for other useful protocol 136 * references see: Comer, KA9Q NOS, and 137 * for a reference on the difference 138 * between specifications and how BSD 139 * works see the 4.4lite source. 140 * A.N.Kuznetsov : Don't time wait on completion of tidy 141 * close. 142 * Linus Torvalds : Fin/Shutdown & copied_seq changes. 143 * Linus Torvalds : Fixed BSD port reuse to work first syn 144 * Alan Cox : Reimplemented timers as per the RFC 145 * and using multiple timers for sanity. 146 * Alan Cox : Small bug fixes, and a lot of new 147 * comments. 148 * Alan Cox : Fixed dual reader crash by locking 149 * the buffers (much like datagram.c) 150 * Alan Cox : Fixed stuck sockets in probe. A probe 151 * now gets fed up of retrying without 152 * (even a no space) answer. 153 * Alan Cox : Extracted closing code better 154 * Alan Cox : Fixed the closing state machine to 155 * resemble the RFC. 156 * Alan Cox : More 'per spec' fixes. 157 * Jorge Cwik : Even faster checksumming. 158 * Alan Cox : tcp_data() doesn't ack illegal PSH 159 * only frames. At least one pc tcp stack 160 * generates them. 161 * Alan Cox : Cache last socket. 162 * Alan Cox : Per route irtt. 163 * Matt Day : poll()->select() match BSD precisely on error 164 * Alan Cox : New buffers 165 * Marc Tamsky : Various sk->prot->retransmits and 166 * sk->retransmits misupdating fixed. 167 * Fixed tcp_write_timeout: stuck close, 168 * and TCP syn retries gets used now. 169 * Mark Yarvis : In tcp_read_wakeup(), don't send an 170 * ack if state is TCP_CLOSED. 171 * Alan Cox : Look up device on a retransmit - routes may 172 * change. Doesn't yet cope with MSS shrink right 173 * but it's a start! 174 * Marc Tamsky : Closing in closing fixes. 175 * Mike Shaver : RFC1122 verifications. 176 * Alan Cox : rcv_saddr errors. 177 * Alan Cox : Block double connect(). 178 * Alan Cox : Small hooks for enSKIP. 179 * Alexey Kuznetsov: Path MTU discovery. 180 * Alan Cox : Support soft errors. 181 * Alan Cox : Fix MTU discovery pathological case 182 * when the remote claims no mtu! 183 * Marc Tamsky : TCP_CLOSE fix. 184 * Colin (G3TNE) : Send a reset on syn ack replies in 185 * window but wrong (fixes NT lpd problems) 186 * Pedro Roque : Better TCP window handling, delayed ack. 187 * Joerg Reuter : No modification of locked buffers in 188 * tcp_do_retransmit() 189 * Eric Schenk : Changed receiver side silly window 190 * avoidance algorithm to BSD style 191 * algorithm. This doubles throughput 192 * against machines running Solaris, 193 * and seems to result in general 194 * improvement. 195 * Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD 196 * Willy Konynenberg : Transparent proxying support. 197 * Mike McLagan : Routing by source 198 * Keith Owens : Do proper merging with partial SKB's in 199 * tcp_do_sendmsg to avoid burstiness. 200 * Eric Schenk : Fix fast close down bug with 201 * shutdown() followed by close(). 202 * Andi Kleen : Make poll agree with SIGIO 203 * Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and 204 * lingertime == 0 (RFC 793 ABORT Call) 205 * Hirokazu Takahashi : Use copy_from_user() instead of 206 * csum_and_copy_from_user() if possible. 207 * 208 * This program is free software; you can redistribute it and/or 209 * modify it under the terms of the GNU General Public License 210 * as published by the Free Software Foundation; either version 211 * 2 of the License, or(at your option) any later version. 212 * 213 * Description of States: 214 * 215 * TCP_SYN_SENT sent a connection request, waiting for ack 216 * 217 * TCP_SYN_RECV received a connection request, sent ack, 218 * waiting for final ack in three-way handshake. 219 * 220 * TCP_ESTABLISHED connection established 221 * 222 * TCP_FIN_WAIT1 our side has shutdown, waiting to complete 223 * transmission of remaining buffered data 224 * 225 * TCP_FIN_WAIT2 all buffered data sent, waiting for remote 226 * to shutdown 227 * 228 * TCP_CLOSING both sides have shutdown but we still have 229 * data we have to finish sending 230 * 231 * TCP_TIME_WAIT timeout to catch resent junk before entering 232 * closed, can only be entered from FIN_WAIT2 233 * or CLOSING. Required because the other end 234 * may not have gotten our last ACK causing it 235 * to retransmit the data packet (which we ignore) 236 * 237 * TCP_CLOSE_WAIT remote side has shutdown and is waiting for 238 * us to finish writing our data and to shutdown 239 * (we have to close() to move on to LAST_ACK) 240 * 241 * TCP_LAST_ACK out side has shutdown after remote has 242 * shutdown. There may still be data in our 243 * buffer that we have to finish sending 244 * 245 * TCP_CLOSE socket is finished 246 */ 247 248 #include <linux/kernel.h> 249 #include <linux/module.h> 250 #include <linux/types.h> 251 #include <linux/fcntl.h> 252 #include <linux/poll.h> 253 #include <linux/init.h> 254 #include <linux/fs.h> 255 #include <linux/skbuff.h> 256 #include <linux/scatterlist.h> 257 #include <linux/splice.h> 258 #include <linux/net.h> 259 #include <linux/socket.h> 260 #include <linux/random.h> 261 #include <linux/bootmem.h> 262 #include <linux/highmem.h> 263 #include <linux/swap.h> 264 #include <linux/cache.h> 265 #include <linux/err.h> 266 #include <linux/crypto.h> 267 #include <linux/time.h> 268 #include <linux/slab.h> 269 270 #include <net/icmp.h> 271 #include <net/tcp.h> 272 #include <net/xfrm.h> 273 #include <net/ip.h> 274 #include <net/netdma.h> 275 #include <net/sock.h> 276 277 #include <asm/uaccess.h> 278 #include <asm/ioctls.h> 279 280 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 281 282 struct percpu_counter tcp_orphan_count; 283 EXPORT_SYMBOL_GPL(tcp_orphan_count); 284 285 long sysctl_tcp_mem[3] __read_mostly; 286 int sysctl_tcp_wmem[3] __read_mostly; 287 int sysctl_tcp_rmem[3] __read_mostly; 288 289 EXPORT_SYMBOL(sysctl_tcp_mem); 290 EXPORT_SYMBOL(sysctl_tcp_rmem); 291 EXPORT_SYMBOL(sysctl_tcp_wmem); 292 293 atomic_long_t tcp_memory_allocated; /* Current allocated memory. */ 294 EXPORT_SYMBOL(tcp_memory_allocated); 295 296 /* 297 * Current number of TCP sockets. 298 */ 299 struct percpu_counter tcp_sockets_allocated; 300 EXPORT_SYMBOL(tcp_sockets_allocated); 301 302 /* 303 * TCP splice context 304 */ 305 struct tcp_splice_state { 306 struct pipe_inode_info *pipe; 307 size_t len; 308 unsigned int flags; 309 }; 310 311 /* 312 * Pressure flag: try to collapse. 313 * Technical note: it is used by multiple contexts non atomically. 314 * All the __sk_mem_schedule() is of this nature: accounting 315 * is strict, actions are advisory and have some latency. 316 */ 317 int tcp_memory_pressure __read_mostly; 318 EXPORT_SYMBOL(tcp_memory_pressure); 319 320 void tcp_enter_memory_pressure(struct sock *sk) 321 { 322 if (!tcp_memory_pressure) { 323 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES); 324 tcp_memory_pressure = 1; 325 } 326 } 327 EXPORT_SYMBOL(tcp_enter_memory_pressure); 328 329 /* Convert seconds to retransmits based on initial and max timeout */ 330 static u8 secs_to_retrans(int seconds, int timeout, int rto_max) 331 { 332 u8 res = 0; 333 334 if (seconds > 0) { 335 int period = timeout; 336 337 res = 1; 338 while (seconds > period && res < 255) { 339 res++; 340 timeout <<= 1; 341 if (timeout > rto_max) 342 timeout = rto_max; 343 period += timeout; 344 } 345 } 346 return res; 347 } 348 349 /* Convert retransmits to seconds based on initial and max timeout */ 350 static int retrans_to_secs(u8 retrans, int timeout, int rto_max) 351 { 352 int period = 0; 353 354 if (retrans > 0) { 355 period = timeout; 356 while (--retrans) { 357 timeout <<= 1; 358 if (timeout > rto_max) 359 timeout = rto_max; 360 period += timeout; 361 } 362 } 363 return period; 364 } 365 366 /* 367 * Wait for a TCP event. 368 * 369 * Note that we don't need to lock the socket, as the upper poll layers 370 * take care of normal races (between the test and the event) and we don't 371 * go look at any of the socket buffers directly. 372 */ 373 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 374 { 375 unsigned int mask; 376 struct sock *sk = sock->sk; 377 struct tcp_sock *tp = tcp_sk(sk); 378 379 sock_poll_wait(file, sk_sleep(sk), wait); 380 if (sk->sk_state == TCP_LISTEN) 381 return inet_csk_listen_poll(sk); 382 383 /* Socket is not locked. We are protected from async events 384 * by poll logic and correct handling of state changes 385 * made by other threads is impossible in any case. 386 */ 387 388 mask = 0; 389 390 /* 391 * POLLHUP is certainly not done right. But poll() doesn't 392 * have a notion of HUP in just one direction, and for a 393 * socket the read side is more interesting. 394 * 395 * Some poll() documentation says that POLLHUP is incompatible 396 * with the POLLOUT/POLLWR flags, so somebody should check this 397 * all. But careful, it tends to be safer to return too many 398 * bits than too few, and you can easily break real applications 399 * if you don't tell them that something has hung up! 400 * 401 * Check-me. 402 * 403 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 404 * our fs/select.c). It means that after we received EOF, 405 * poll always returns immediately, making impossible poll() on write() 406 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 407 * if and only if shutdown has been made in both directions. 408 * Actually, it is interesting to look how Solaris and DUX 409 * solve this dilemma. I would prefer, if POLLHUP were maskable, 410 * then we could set it on SND_SHUTDOWN. BTW examples given 411 * in Stevens' books assume exactly this behaviour, it explains 412 * why POLLHUP is incompatible with POLLOUT. --ANK 413 * 414 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 415 * blocking on fresh not-connected or disconnected socket. --ANK 416 */ 417 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 418 mask |= POLLHUP; 419 if (sk->sk_shutdown & RCV_SHUTDOWN) 420 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 421 422 /* Connected? */ 423 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) { 424 int target = sock_rcvlowat(sk, 0, INT_MAX); 425 426 if (tp->urg_seq == tp->copied_seq && 427 !sock_flag(sk, SOCK_URGINLINE) && 428 tp->urg_data) 429 target++; 430 431 /* Potential race condition. If read of tp below will 432 * escape above sk->sk_state, we can be illegally awaken 433 * in SYN_* states. */ 434 if (tp->rcv_nxt - tp->copied_seq >= target) 435 mask |= POLLIN | POLLRDNORM; 436 437 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 438 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) { 439 mask |= POLLOUT | POLLWRNORM; 440 } else { /* send SIGIO later */ 441 set_bit(SOCK_ASYNC_NOSPACE, 442 &sk->sk_socket->flags); 443 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 444 445 /* Race breaker. If space is freed after 446 * wspace test but before the flags are set, 447 * IO signal will be lost. 448 */ 449 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) 450 mask |= POLLOUT | POLLWRNORM; 451 } 452 } else 453 mask |= POLLOUT | POLLWRNORM; 454 455 if (tp->urg_data & TCP_URG_VALID) 456 mask |= POLLPRI; 457 } 458 /* This barrier is coupled with smp_wmb() in tcp_reset() */ 459 smp_rmb(); 460 if (sk->sk_err) 461 mask |= POLLERR; 462 463 return mask; 464 } 465 EXPORT_SYMBOL(tcp_poll); 466 467 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 468 { 469 struct tcp_sock *tp = tcp_sk(sk); 470 int answ; 471 472 switch (cmd) { 473 case SIOCINQ: 474 if (sk->sk_state == TCP_LISTEN) 475 return -EINVAL; 476 477 lock_sock(sk); 478 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 479 answ = 0; 480 else if (sock_flag(sk, SOCK_URGINLINE) || 481 !tp->urg_data || 482 before(tp->urg_seq, tp->copied_seq) || 483 !before(tp->urg_seq, tp->rcv_nxt)) { 484 struct sk_buff *skb; 485 486 answ = tp->rcv_nxt - tp->copied_seq; 487 488 /* Subtract 1, if FIN is in queue. */ 489 skb = skb_peek_tail(&sk->sk_receive_queue); 490 if (answ && skb) 491 answ -= tcp_hdr(skb)->fin; 492 } else 493 answ = tp->urg_seq - tp->copied_seq; 494 release_sock(sk); 495 break; 496 case SIOCATMARK: 497 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 498 break; 499 case SIOCOUTQ: 500 if (sk->sk_state == TCP_LISTEN) 501 return -EINVAL; 502 503 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 504 answ = 0; 505 else 506 answ = tp->write_seq - tp->snd_una; 507 break; 508 case SIOCOUTQNSD: 509 if (sk->sk_state == TCP_LISTEN) 510 return -EINVAL; 511 512 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 513 answ = 0; 514 else 515 answ = tp->write_seq - tp->snd_nxt; 516 break; 517 default: 518 return -ENOIOCTLCMD; 519 } 520 521 return put_user(answ, (int __user *)arg); 522 } 523 EXPORT_SYMBOL(tcp_ioctl); 524 525 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 526 { 527 TCP_SKB_CB(skb)->flags |= TCPHDR_PSH; 528 tp->pushed_seq = tp->write_seq; 529 } 530 531 static inline int forced_push(struct tcp_sock *tp) 532 { 533 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 534 } 535 536 static inline void skb_entail(struct sock *sk, struct sk_buff *skb) 537 { 538 struct tcp_sock *tp = tcp_sk(sk); 539 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 540 541 skb->csum = 0; 542 tcb->seq = tcb->end_seq = tp->write_seq; 543 tcb->flags = TCPHDR_ACK; 544 tcb->sacked = 0; 545 skb_header_release(skb); 546 tcp_add_write_queue_tail(sk, skb); 547 sk->sk_wmem_queued += skb->truesize; 548 sk_mem_charge(sk, skb->truesize); 549 if (tp->nonagle & TCP_NAGLE_PUSH) 550 tp->nonagle &= ~TCP_NAGLE_PUSH; 551 } 552 553 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags) 554 { 555 if (flags & MSG_OOB) 556 tp->snd_up = tp->write_seq; 557 } 558 559 static inline void tcp_push(struct sock *sk, int flags, int mss_now, 560 int nonagle) 561 { 562 if (tcp_send_head(sk)) { 563 struct tcp_sock *tp = tcp_sk(sk); 564 565 if (!(flags & MSG_MORE) || forced_push(tp)) 566 tcp_mark_push(tp, tcp_write_queue_tail(sk)); 567 568 tcp_mark_urg(tp, flags); 569 __tcp_push_pending_frames(sk, mss_now, 570 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle); 571 } 572 } 573 574 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, 575 unsigned int offset, size_t len) 576 { 577 struct tcp_splice_state *tss = rd_desc->arg.data; 578 int ret; 579 580 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len), 581 tss->flags); 582 if (ret > 0) 583 rd_desc->count -= ret; 584 return ret; 585 } 586 587 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss) 588 { 589 /* Store TCP splice context information in read_descriptor_t. */ 590 read_descriptor_t rd_desc = { 591 .arg.data = tss, 592 .count = tss->len, 593 }; 594 595 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv); 596 } 597 598 /** 599 * tcp_splice_read - splice data from TCP socket to a pipe 600 * @sock: socket to splice from 601 * @ppos: position (not valid) 602 * @pipe: pipe to splice to 603 * @len: number of bytes to splice 604 * @flags: splice modifier flags 605 * 606 * Description: 607 * Will read pages from given socket and fill them into a pipe. 608 * 609 **/ 610 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, 611 struct pipe_inode_info *pipe, size_t len, 612 unsigned int flags) 613 { 614 struct sock *sk = sock->sk; 615 struct tcp_splice_state tss = { 616 .pipe = pipe, 617 .len = len, 618 .flags = flags, 619 }; 620 long timeo; 621 ssize_t spliced; 622 int ret; 623 624 sock_rps_record_flow(sk); 625 /* 626 * We can't seek on a socket input 627 */ 628 if (unlikely(*ppos)) 629 return -ESPIPE; 630 631 ret = spliced = 0; 632 633 lock_sock(sk); 634 635 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK); 636 while (tss.len) { 637 ret = __tcp_splice_read(sk, &tss); 638 if (ret < 0) 639 break; 640 else if (!ret) { 641 if (spliced) 642 break; 643 if (sock_flag(sk, SOCK_DONE)) 644 break; 645 if (sk->sk_err) { 646 ret = sock_error(sk); 647 break; 648 } 649 if (sk->sk_shutdown & RCV_SHUTDOWN) 650 break; 651 if (sk->sk_state == TCP_CLOSE) { 652 /* 653 * This occurs when user tries to read 654 * from never connected socket. 655 */ 656 if (!sock_flag(sk, SOCK_DONE)) 657 ret = -ENOTCONN; 658 break; 659 } 660 if (!timeo) { 661 ret = -EAGAIN; 662 break; 663 } 664 sk_wait_data(sk, &timeo); 665 if (signal_pending(current)) { 666 ret = sock_intr_errno(timeo); 667 break; 668 } 669 continue; 670 } 671 tss.len -= ret; 672 spliced += ret; 673 674 if (!timeo) 675 break; 676 release_sock(sk); 677 lock_sock(sk); 678 679 if (sk->sk_err || sk->sk_state == TCP_CLOSE || 680 (sk->sk_shutdown & RCV_SHUTDOWN) || 681 signal_pending(current)) 682 break; 683 } 684 685 release_sock(sk); 686 687 if (spliced) 688 return spliced; 689 690 return ret; 691 } 692 EXPORT_SYMBOL(tcp_splice_read); 693 694 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp) 695 { 696 struct sk_buff *skb; 697 698 /* The TCP header must be at least 32-bit aligned. */ 699 size = ALIGN(size, 4); 700 701 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); 702 if (skb) { 703 if (sk_wmem_schedule(sk, skb->truesize)) { 704 /* 705 * Make sure that we have exactly size bytes 706 * available to the caller, no more, no less. 707 */ 708 skb_reserve(skb, skb_tailroom(skb) - size); 709 return skb; 710 } 711 __kfree_skb(skb); 712 } else { 713 sk->sk_prot->enter_memory_pressure(sk); 714 sk_stream_moderate_sndbuf(sk); 715 } 716 return NULL; 717 } 718 719 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now, 720 int large_allowed) 721 { 722 struct tcp_sock *tp = tcp_sk(sk); 723 u32 xmit_size_goal, old_size_goal; 724 725 xmit_size_goal = mss_now; 726 727 if (large_allowed && sk_can_gso(sk)) { 728 xmit_size_goal = ((sk->sk_gso_max_size - 1) - 729 inet_csk(sk)->icsk_af_ops->net_header_len - 730 inet_csk(sk)->icsk_ext_hdr_len - 731 tp->tcp_header_len); 732 733 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal); 734 735 /* We try hard to avoid divides here */ 736 old_size_goal = tp->xmit_size_goal_segs * mss_now; 737 738 if (likely(old_size_goal <= xmit_size_goal && 739 old_size_goal + mss_now > xmit_size_goal)) { 740 xmit_size_goal = old_size_goal; 741 } else { 742 tp->xmit_size_goal_segs = xmit_size_goal / mss_now; 743 xmit_size_goal = tp->xmit_size_goal_segs * mss_now; 744 } 745 } 746 747 return max(xmit_size_goal, mss_now); 748 } 749 750 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags) 751 { 752 int mss_now; 753 754 mss_now = tcp_current_mss(sk); 755 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB)); 756 757 return mss_now; 758 } 759 760 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, 761 size_t psize, int flags) 762 { 763 struct tcp_sock *tp = tcp_sk(sk); 764 int mss_now, size_goal; 765 int err; 766 ssize_t copied; 767 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 768 769 /* Wait for a connection to finish. */ 770 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 771 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 772 goto out_err; 773 774 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 775 776 mss_now = tcp_send_mss(sk, &size_goal, flags); 777 copied = 0; 778 779 err = -EPIPE; 780 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 781 goto out_err; 782 783 while (psize > 0) { 784 struct sk_buff *skb = tcp_write_queue_tail(sk); 785 struct page *page = pages[poffset / PAGE_SIZE]; 786 int copy, i, can_coalesce; 787 int offset = poffset % PAGE_SIZE; 788 int size = min_t(size_t, psize, PAGE_SIZE - offset); 789 790 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { 791 new_segment: 792 if (!sk_stream_memory_free(sk)) 793 goto wait_for_sndbuf; 794 795 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation); 796 if (!skb) 797 goto wait_for_memory; 798 799 skb_entail(sk, skb); 800 copy = size_goal; 801 } 802 803 if (copy > size) 804 copy = size; 805 806 i = skb_shinfo(skb)->nr_frags; 807 can_coalesce = skb_can_coalesce(skb, i, page, offset); 808 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 809 tcp_mark_push(tp, skb); 810 goto new_segment; 811 } 812 if (!sk_wmem_schedule(sk, copy)) 813 goto wait_for_memory; 814 815 if (can_coalesce) { 816 skb_shinfo(skb)->frags[i - 1].size += copy; 817 } else { 818 get_page(page); 819 skb_fill_page_desc(skb, i, page, offset, copy); 820 } 821 822 skb->len += copy; 823 skb->data_len += copy; 824 skb->truesize += copy; 825 sk->sk_wmem_queued += copy; 826 sk_mem_charge(sk, copy); 827 skb->ip_summed = CHECKSUM_PARTIAL; 828 tp->write_seq += copy; 829 TCP_SKB_CB(skb)->end_seq += copy; 830 skb_shinfo(skb)->gso_segs = 0; 831 832 if (!copied) 833 TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH; 834 835 copied += copy; 836 poffset += copy; 837 if (!(psize -= copy)) 838 goto out; 839 840 if (skb->len < size_goal || (flags & MSG_OOB)) 841 continue; 842 843 if (forced_push(tp)) { 844 tcp_mark_push(tp, skb); 845 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 846 } else if (skb == tcp_send_head(sk)) 847 tcp_push_one(sk, mss_now); 848 continue; 849 850 wait_for_sndbuf: 851 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 852 wait_for_memory: 853 if (copied) 854 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 855 856 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 857 goto do_error; 858 859 mss_now = tcp_send_mss(sk, &size_goal, flags); 860 } 861 862 out: 863 if (copied) 864 tcp_push(sk, flags, mss_now, tp->nonagle); 865 return copied; 866 867 do_error: 868 if (copied) 869 goto out; 870 out_err: 871 return sk_stream_error(sk, flags, err); 872 } 873 874 int tcp_sendpage(struct sock *sk, struct page *page, int offset, 875 size_t size, int flags) 876 { 877 ssize_t res; 878 879 if (!(sk->sk_route_caps & NETIF_F_SG) || 880 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 881 return sock_no_sendpage(sk->sk_socket, page, offset, size, 882 flags); 883 884 lock_sock(sk); 885 res = do_tcp_sendpages(sk, &page, offset, size, flags); 886 release_sock(sk); 887 return res; 888 } 889 EXPORT_SYMBOL(tcp_sendpage); 890 891 #define TCP_PAGE(sk) (sk->sk_sndmsg_page) 892 #define TCP_OFF(sk) (sk->sk_sndmsg_off) 893 894 static inline int select_size(struct sock *sk, int sg) 895 { 896 struct tcp_sock *tp = tcp_sk(sk); 897 int tmp = tp->mss_cache; 898 899 if (sg) { 900 if (sk_can_gso(sk)) 901 tmp = 0; 902 else { 903 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 904 905 if (tmp >= pgbreak && 906 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 907 tmp = pgbreak; 908 } 909 } 910 911 return tmp; 912 } 913 914 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 915 size_t size) 916 { 917 struct iovec *iov; 918 struct tcp_sock *tp = tcp_sk(sk); 919 struct sk_buff *skb; 920 int iovlen, flags; 921 int mss_now, size_goal; 922 int sg, err, copied; 923 long timeo; 924 925 lock_sock(sk); 926 927 flags = msg->msg_flags; 928 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 929 930 /* Wait for a connection to finish. */ 931 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 932 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 933 goto out_err; 934 935 /* This should be in poll */ 936 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 937 938 mss_now = tcp_send_mss(sk, &size_goal, flags); 939 940 /* Ok commence sending. */ 941 iovlen = msg->msg_iovlen; 942 iov = msg->msg_iov; 943 copied = 0; 944 945 err = -EPIPE; 946 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 947 goto out_err; 948 949 sg = sk->sk_route_caps & NETIF_F_SG; 950 951 while (--iovlen >= 0) { 952 size_t seglen = iov->iov_len; 953 unsigned char __user *from = iov->iov_base; 954 955 iov++; 956 957 while (seglen > 0) { 958 int copy = 0; 959 int max = size_goal; 960 961 skb = tcp_write_queue_tail(sk); 962 if (tcp_send_head(sk)) { 963 if (skb->ip_summed == CHECKSUM_NONE) 964 max = mss_now; 965 copy = max - skb->len; 966 } 967 968 if (copy <= 0) { 969 new_segment: 970 /* Allocate new segment. If the interface is SG, 971 * allocate skb fitting to single page. 972 */ 973 if (!sk_stream_memory_free(sk)) 974 goto wait_for_sndbuf; 975 976 skb = sk_stream_alloc_skb(sk, 977 select_size(sk, sg), 978 sk->sk_allocation); 979 if (!skb) 980 goto wait_for_memory; 981 982 /* 983 * Check whether we can use HW checksum. 984 */ 985 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 986 skb->ip_summed = CHECKSUM_PARTIAL; 987 988 skb_entail(sk, skb); 989 copy = size_goal; 990 max = size_goal; 991 } 992 993 /* Try to append data to the end of skb. */ 994 if (copy > seglen) 995 copy = seglen; 996 997 /* Where to copy to? */ 998 if (skb_tailroom(skb) > 0) { 999 /* We have some space in skb head. Superb! */ 1000 if (copy > skb_tailroom(skb)) 1001 copy = skb_tailroom(skb); 1002 if ((err = skb_add_data(skb, from, copy)) != 0) 1003 goto do_fault; 1004 } else { 1005 int merge = 0; 1006 int i = skb_shinfo(skb)->nr_frags; 1007 struct page *page = TCP_PAGE(sk); 1008 int off = TCP_OFF(sk); 1009 1010 if (skb_can_coalesce(skb, i, page, off) && 1011 off != PAGE_SIZE) { 1012 /* We can extend the last page 1013 * fragment. */ 1014 merge = 1; 1015 } else if (i == MAX_SKB_FRAGS || !sg) { 1016 /* Need to add new fragment and cannot 1017 * do this because interface is non-SG, 1018 * or because all the page slots are 1019 * busy. */ 1020 tcp_mark_push(tp, skb); 1021 goto new_segment; 1022 } else if (page) { 1023 if (off == PAGE_SIZE) { 1024 put_page(page); 1025 TCP_PAGE(sk) = page = NULL; 1026 off = 0; 1027 } 1028 } else 1029 off = 0; 1030 1031 if (copy > PAGE_SIZE - off) 1032 copy = PAGE_SIZE - off; 1033 1034 if (!sk_wmem_schedule(sk, copy)) 1035 goto wait_for_memory; 1036 1037 if (!page) { 1038 /* Allocate new cache page. */ 1039 if (!(page = sk_stream_alloc_page(sk))) 1040 goto wait_for_memory; 1041 } 1042 1043 /* Time to copy data. We are close to 1044 * the end! */ 1045 err = skb_copy_to_page(sk, from, skb, page, 1046 off, copy); 1047 if (err) { 1048 /* If this page was new, give it to the 1049 * socket so it does not get leaked. 1050 */ 1051 if (!TCP_PAGE(sk)) { 1052 TCP_PAGE(sk) = page; 1053 TCP_OFF(sk) = 0; 1054 } 1055 goto do_error; 1056 } 1057 1058 /* Update the skb. */ 1059 if (merge) { 1060 skb_shinfo(skb)->frags[i - 1].size += 1061 copy; 1062 } else { 1063 skb_fill_page_desc(skb, i, page, off, copy); 1064 if (TCP_PAGE(sk)) { 1065 get_page(page); 1066 } else if (off + copy < PAGE_SIZE) { 1067 get_page(page); 1068 TCP_PAGE(sk) = page; 1069 } 1070 } 1071 1072 TCP_OFF(sk) = off + copy; 1073 } 1074 1075 if (!copied) 1076 TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH; 1077 1078 tp->write_seq += copy; 1079 TCP_SKB_CB(skb)->end_seq += copy; 1080 skb_shinfo(skb)->gso_segs = 0; 1081 1082 from += copy; 1083 copied += copy; 1084 if ((seglen -= copy) == 0 && iovlen == 0) 1085 goto out; 1086 1087 if (skb->len < max || (flags & MSG_OOB)) 1088 continue; 1089 1090 if (forced_push(tp)) { 1091 tcp_mark_push(tp, skb); 1092 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 1093 } else if (skb == tcp_send_head(sk)) 1094 tcp_push_one(sk, mss_now); 1095 continue; 1096 1097 wait_for_sndbuf: 1098 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1099 wait_for_memory: 1100 if (copied) 1101 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 1102 1103 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 1104 goto do_error; 1105 1106 mss_now = tcp_send_mss(sk, &size_goal, flags); 1107 } 1108 } 1109 1110 out: 1111 if (copied) 1112 tcp_push(sk, flags, mss_now, tp->nonagle); 1113 release_sock(sk); 1114 return copied; 1115 1116 do_fault: 1117 if (!skb->len) { 1118 tcp_unlink_write_queue(skb, sk); 1119 /* It is the one place in all of TCP, except connection 1120 * reset, where we can be unlinking the send_head. 1121 */ 1122 tcp_check_send_head(sk, skb); 1123 sk_wmem_free_skb(sk, skb); 1124 } 1125 1126 do_error: 1127 if (copied) 1128 goto out; 1129 out_err: 1130 err = sk_stream_error(sk, flags, err); 1131 release_sock(sk); 1132 return err; 1133 } 1134 EXPORT_SYMBOL(tcp_sendmsg); 1135 1136 /* 1137 * Handle reading urgent data. BSD has very simple semantics for 1138 * this, no blocking and very strange errors 8) 1139 */ 1140 1141 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags) 1142 { 1143 struct tcp_sock *tp = tcp_sk(sk); 1144 1145 /* No URG data to read. */ 1146 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || 1147 tp->urg_data == TCP_URG_READ) 1148 return -EINVAL; /* Yes this is right ! */ 1149 1150 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) 1151 return -ENOTCONN; 1152 1153 if (tp->urg_data & TCP_URG_VALID) { 1154 int err = 0; 1155 char c = tp->urg_data; 1156 1157 if (!(flags & MSG_PEEK)) 1158 tp->urg_data = TCP_URG_READ; 1159 1160 /* Read urgent data. */ 1161 msg->msg_flags |= MSG_OOB; 1162 1163 if (len > 0) { 1164 if (!(flags & MSG_TRUNC)) 1165 err = memcpy_toiovec(msg->msg_iov, &c, 1); 1166 len = 1; 1167 } else 1168 msg->msg_flags |= MSG_TRUNC; 1169 1170 return err ? -EFAULT : len; 1171 } 1172 1173 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 1174 return 0; 1175 1176 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and 1177 * the available implementations agree in this case: 1178 * this call should never block, independent of the 1179 * blocking state of the socket. 1180 * Mike <pall@rz.uni-karlsruhe.de> 1181 */ 1182 return -EAGAIN; 1183 } 1184 1185 /* Clean up the receive buffer for full frames taken by the user, 1186 * then send an ACK if necessary. COPIED is the number of bytes 1187 * tcp_recvmsg has given to the user so far, it speeds up the 1188 * calculation of whether or not we must ACK for the sake of 1189 * a window update. 1190 */ 1191 void tcp_cleanup_rbuf(struct sock *sk, int copied) 1192 { 1193 struct tcp_sock *tp = tcp_sk(sk); 1194 int time_to_ack = 0; 1195 1196 #if TCP_DEBUG 1197 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); 1198 1199 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq), 1200 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n", 1201 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt); 1202 #endif 1203 1204 if (inet_csk_ack_scheduled(sk)) { 1205 const struct inet_connection_sock *icsk = inet_csk(sk); 1206 /* Delayed ACKs frequently hit locked sockets during bulk 1207 * receive. */ 1208 if (icsk->icsk_ack.blocked || 1209 /* Once-per-two-segments ACK was not sent by tcp_input.c */ 1210 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || 1211 /* 1212 * If this read emptied read buffer, we send ACK, if 1213 * connection is not bidirectional, user drained 1214 * receive buffer and there was a small segment 1215 * in queue. 1216 */ 1217 (copied > 0 && 1218 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || 1219 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && 1220 !icsk->icsk_ack.pingpong)) && 1221 !atomic_read(&sk->sk_rmem_alloc))) 1222 time_to_ack = 1; 1223 } 1224 1225 /* We send an ACK if we can now advertise a non-zero window 1226 * which has been raised "significantly". 1227 * 1228 * Even if window raised up to infinity, do not send window open ACK 1229 * in states, where we will not receive more. It is useless. 1230 */ 1231 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 1232 __u32 rcv_window_now = tcp_receive_window(tp); 1233 1234 /* Optimize, __tcp_select_window() is not cheap. */ 1235 if (2*rcv_window_now <= tp->window_clamp) { 1236 __u32 new_window = __tcp_select_window(sk); 1237 1238 /* Send ACK now, if this read freed lots of space 1239 * in our buffer. Certainly, new_window is new window. 1240 * We can advertise it now, if it is not less than current one. 1241 * "Lots" means "at least twice" here. 1242 */ 1243 if (new_window && new_window >= 2 * rcv_window_now) 1244 time_to_ack = 1; 1245 } 1246 } 1247 if (time_to_ack) 1248 tcp_send_ack(sk); 1249 } 1250 1251 static void tcp_prequeue_process(struct sock *sk) 1252 { 1253 struct sk_buff *skb; 1254 struct tcp_sock *tp = tcp_sk(sk); 1255 1256 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED); 1257 1258 /* RX process wants to run with disabled BHs, though it is not 1259 * necessary */ 1260 local_bh_disable(); 1261 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) 1262 sk_backlog_rcv(sk, skb); 1263 local_bh_enable(); 1264 1265 /* Clear memory counter. */ 1266 tp->ucopy.memory = 0; 1267 } 1268 1269 #ifdef CONFIG_NET_DMA 1270 static void tcp_service_net_dma(struct sock *sk, bool wait) 1271 { 1272 dma_cookie_t done, used; 1273 dma_cookie_t last_issued; 1274 struct tcp_sock *tp = tcp_sk(sk); 1275 1276 if (!tp->ucopy.dma_chan) 1277 return; 1278 1279 last_issued = tp->ucopy.dma_cookie; 1280 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1281 1282 do { 1283 if (dma_async_memcpy_complete(tp->ucopy.dma_chan, 1284 last_issued, &done, 1285 &used) == DMA_SUCCESS) { 1286 /* Safe to free early-copied skbs now */ 1287 __skb_queue_purge(&sk->sk_async_wait_queue); 1288 break; 1289 } else { 1290 struct sk_buff *skb; 1291 while ((skb = skb_peek(&sk->sk_async_wait_queue)) && 1292 (dma_async_is_complete(skb->dma_cookie, done, 1293 used) == DMA_SUCCESS)) { 1294 __skb_dequeue(&sk->sk_async_wait_queue); 1295 kfree_skb(skb); 1296 } 1297 } 1298 } while (wait); 1299 } 1300 #endif 1301 1302 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 1303 { 1304 struct sk_buff *skb; 1305 u32 offset; 1306 1307 skb_queue_walk(&sk->sk_receive_queue, skb) { 1308 offset = seq - TCP_SKB_CB(skb)->seq; 1309 if (tcp_hdr(skb)->syn) 1310 offset--; 1311 if (offset < skb->len || tcp_hdr(skb)->fin) { 1312 *off = offset; 1313 return skb; 1314 } 1315 } 1316 return NULL; 1317 } 1318 1319 /* 1320 * This routine provides an alternative to tcp_recvmsg() for routines 1321 * that would like to handle copying from skbuffs directly in 'sendfile' 1322 * fashion. 1323 * Note: 1324 * - It is assumed that the socket was locked by the caller. 1325 * - The routine does not block. 1326 * - At present, there is no support for reading OOB data 1327 * or for 'peeking' the socket using this routine 1328 * (although both would be easy to implement). 1329 */ 1330 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 1331 sk_read_actor_t recv_actor) 1332 { 1333 struct sk_buff *skb; 1334 struct tcp_sock *tp = tcp_sk(sk); 1335 u32 seq = tp->copied_seq; 1336 u32 offset; 1337 int copied = 0; 1338 1339 if (sk->sk_state == TCP_LISTEN) 1340 return -ENOTCONN; 1341 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { 1342 if (offset < skb->len) { 1343 int used; 1344 size_t len; 1345 1346 len = skb->len - offset; 1347 /* Stop reading if we hit a patch of urgent data */ 1348 if (tp->urg_data) { 1349 u32 urg_offset = tp->urg_seq - seq; 1350 if (urg_offset < len) 1351 len = urg_offset; 1352 if (!len) 1353 break; 1354 } 1355 used = recv_actor(desc, skb, offset, len); 1356 if (used < 0) { 1357 if (!copied) 1358 copied = used; 1359 break; 1360 } else if (used <= len) { 1361 seq += used; 1362 copied += used; 1363 offset += used; 1364 } 1365 /* 1366 * If recv_actor drops the lock (e.g. TCP splice 1367 * receive) the skb pointer might be invalid when 1368 * getting here: tcp_collapse might have deleted it 1369 * while aggregating skbs from the socket queue. 1370 */ 1371 skb = tcp_recv_skb(sk, seq-1, &offset); 1372 if (!skb || (offset+1 != skb->len)) 1373 break; 1374 } 1375 if (tcp_hdr(skb)->fin) { 1376 sk_eat_skb(sk, skb, 0); 1377 ++seq; 1378 break; 1379 } 1380 sk_eat_skb(sk, skb, 0); 1381 if (!desc->count) 1382 break; 1383 tp->copied_seq = seq; 1384 } 1385 tp->copied_seq = seq; 1386 1387 tcp_rcv_space_adjust(sk); 1388 1389 /* Clean up data we have read: This will do ACK frames. */ 1390 if (copied > 0) 1391 tcp_cleanup_rbuf(sk, copied); 1392 return copied; 1393 } 1394 EXPORT_SYMBOL(tcp_read_sock); 1395 1396 /* 1397 * This routine copies from a sock struct into the user buffer. 1398 * 1399 * Technical note: in 2.3 we work on _locked_ socket, so that 1400 * tricks with *seq access order and skb->users are not required. 1401 * Probably, code can be easily improved even more. 1402 */ 1403 1404 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 1405 size_t len, int nonblock, int flags, int *addr_len) 1406 { 1407 struct tcp_sock *tp = tcp_sk(sk); 1408 int copied = 0; 1409 u32 peek_seq; 1410 u32 *seq; 1411 unsigned long used; 1412 int err; 1413 int target; /* Read at least this many bytes */ 1414 long timeo; 1415 struct task_struct *user_recv = NULL; 1416 int copied_early = 0; 1417 struct sk_buff *skb; 1418 u32 urg_hole = 0; 1419 1420 lock_sock(sk); 1421 1422 err = -ENOTCONN; 1423 if (sk->sk_state == TCP_LISTEN) 1424 goto out; 1425 1426 timeo = sock_rcvtimeo(sk, nonblock); 1427 1428 /* Urgent data needs to be handled specially. */ 1429 if (flags & MSG_OOB) 1430 goto recv_urg; 1431 1432 seq = &tp->copied_seq; 1433 if (flags & MSG_PEEK) { 1434 peek_seq = tp->copied_seq; 1435 seq = &peek_seq; 1436 } 1437 1438 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1439 1440 #ifdef CONFIG_NET_DMA 1441 tp->ucopy.dma_chan = NULL; 1442 preempt_disable(); 1443 skb = skb_peek_tail(&sk->sk_receive_queue); 1444 { 1445 int available = 0; 1446 1447 if (skb) 1448 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); 1449 if ((available < target) && 1450 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && 1451 !sysctl_tcp_low_latency && 1452 dma_find_channel(DMA_MEMCPY)) { 1453 preempt_enable_no_resched(); 1454 tp->ucopy.pinned_list = 1455 dma_pin_iovec_pages(msg->msg_iov, len); 1456 } else { 1457 preempt_enable_no_resched(); 1458 } 1459 } 1460 #endif 1461 1462 do { 1463 u32 offset; 1464 1465 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ 1466 if (tp->urg_data && tp->urg_seq == *seq) { 1467 if (copied) 1468 break; 1469 if (signal_pending(current)) { 1470 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; 1471 break; 1472 } 1473 } 1474 1475 /* Next get a buffer. */ 1476 1477 skb_queue_walk(&sk->sk_receive_queue, skb) { 1478 /* Now that we have two receive queues this 1479 * shouldn't happen. 1480 */ 1481 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq), 1482 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n", 1483 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, 1484 flags)) 1485 break; 1486 1487 offset = *seq - TCP_SKB_CB(skb)->seq; 1488 if (tcp_hdr(skb)->syn) 1489 offset--; 1490 if (offset < skb->len) 1491 goto found_ok_skb; 1492 if (tcp_hdr(skb)->fin) 1493 goto found_fin_ok; 1494 WARN(!(flags & MSG_PEEK), 1495 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n", 1496 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags); 1497 } 1498 1499 /* Well, if we have backlog, try to process it now yet. */ 1500 1501 if (copied >= target && !sk->sk_backlog.tail) 1502 break; 1503 1504 if (copied) { 1505 if (sk->sk_err || 1506 sk->sk_state == TCP_CLOSE || 1507 (sk->sk_shutdown & RCV_SHUTDOWN) || 1508 !timeo || 1509 signal_pending(current)) 1510 break; 1511 } else { 1512 if (sock_flag(sk, SOCK_DONE)) 1513 break; 1514 1515 if (sk->sk_err) { 1516 copied = sock_error(sk); 1517 break; 1518 } 1519 1520 if (sk->sk_shutdown & RCV_SHUTDOWN) 1521 break; 1522 1523 if (sk->sk_state == TCP_CLOSE) { 1524 if (!sock_flag(sk, SOCK_DONE)) { 1525 /* This occurs when user tries to read 1526 * from never connected socket. 1527 */ 1528 copied = -ENOTCONN; 1529 break; 1530 } 1531 break; 1532 } 1533 1534 if (!timeo) { 1535 copied = -EAGAIN; 1536 break; 1537 } 1538 1539 if (signal_pending(current)) { 1540 copied = sock_intr_errno(timeo); 1541 break; 1542 } 1543 } 1544 1545 tcp_cleanup_rbuf(sk, copied); 1546 1547 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1548 /* Install new reader */ 1549 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1550 user_recv = current; 1551 tp->ucopy.task = user_recv; 1552 tp->ucopy.iov = msg->msg_iov; 1553 } 1554 1555 tp->ucopy.len = len; 1556 1557 WARN_ON(tp->copied_seq != tp->rcv_nxt && 1558 !(flags & (MSG_PEEK | MSG_TRUNC))); 1559 1560 /* Ugly... If prequeue is not empty, we have to 1561 * process it before releasing socket, otherwise 1562 * order will be broken at second iteration. 1563 * More elegant solution is required!!! 1564 * 1565 * Look: we have the following (pseudo)queues: 1566 * 1567 * 1. packets in flight 1568 * 2. backlog 1569 * 3. prequeue 1570 * 4. receive_queue 1571 * 1572 * Each queue can be processed only if the next ones 1573 * are empty. At this point we have empty receive_queue. 1574 * But prequeue _can_ be not empty after 2nd iteration, 1575 * when we jumped to start of loop because backlog 1576 * processing added something to receive_queue. 1577 * We cannot release_sock(), because backlog contains 1578 * packets arrived _after_ prequeued ones. 1579 * 1580 * Shortly, algorithm is clear --- to process all 1581 * the queues in order. We could make it more directly, 1582 * requeueing packets from backlog to prequeue, if 1583 * is not empty. It is more elegant, but eats cycles, 1584 * unfortunately. 1585 */ 1586 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1587 goto do_prequeue; 1588 1589 /* __ Set realtime policy in scheduler __ */ 1590 } 1591 1592 #ifdef CONFIG_NET_DMA 1593 if (tp->ucopy.dma_chan) 1594 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1595 #endif 1596 if (copied >= target) { 1597 /* Do not sleep, just process backlog. */ 1598 release_sock(sk); 1599 lock_sock(sk); 1600 } else 1601 sk_wait_data(sk, &timeo); 1602 1603 #ifdef CONFIG_NET_DMA 1604 tcp_service_net_dma(sk, false); /* Don't block */ 1605 tp->ucopy.wakeup = 0; 1606 #endif 1607 1608 if (user_recv) { 1609 int chunk; 1610 1611 /* __ Restore normal policy in scheduler __ */ 1612 1613 if ((chunk = len - tp->ucopy.len) != 0) { 1614 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1615 len -= chunk; 1616 copied += chunk; 1617 } 1618 1619 if (tp->rcv_nxt == tp->copied_seq && 1620 !skb_queue_empty(&tp->ucopy.prequeue)) { 1621 do_prequeue: 1622 tcp_prequeue_process(sk); 1623 1624 if ((chunk = len - tp->ucopy.len) != 0) { 1625 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1626 len -= chunk; 1627 copied += chunk; 1628 } 1629 } 1630 } 1631 if ((flags & MSG_PEEK) && 1632 (peek_seq - copied - urg_hole != tp->copied_seq)) { 1633 if (net_ratelimit()) 1634 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n", 1635 current->comm, task_pid_nr(current)); 1636 peek_seq = tp->copied_seq; 1637 } 1638 continue; 1639 1640 found_ok_skb: 1641 /* Ok so how much can we use? */ 1642 used = skb->len - offset; 1643 if (len < used) 1644 used = len; 1645 1646 /* Do we have urgent data here? */ 1647 if (tp->urg_data) { 1648 u32 urg_offset = tp->urg_seq - *seq; 1649 if (urg_offset < used) { 1650 if (!urg_offset) { 1651 if (!sock_flag(sk, SOCK_URGINLINE)) { 1652 ++*seq; 1653 urg_hole++; 1654 offset++; 1655 used--; 1656 if (!used) 1657 goto skip_copy; 1658 } 1659 } else 1660 used = urg_offset; 1661 } 1662 } 1663 1664 if (!(flags & MSG_TRUNC)) { 1665 #ifdef CONFIG_NET_DMA 1666 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) 1667 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY); 1668 1669 if (tp->ucopy.dma_chan) { 1670 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec( 1671 tp->ucopy.dma_chan, skb, offset, 1672 msg->msg_iov, used, 1673 tp->ucopy.pinned_list); 1674 1675 if (tp->ucopy.dma_cookie < 0) { 1676 1677 printk(KERN_ALERT "dma_cookie < 0\n"); 1678 1679 /* Exception. Bailout! */ 1680 if (!copied) 1681 copied = -EFAULT; 1682 break; 1683 } 1684 1685 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1686 1687 if ((offset + used) == skb->len) 1688 copied_early = 1; 1689 1690 } else 1691 #endif 1692 { 1693 err = skb_copy_datagram_iovec(skb, offset, 1694 msg->msg_iov, used); 1695 if (err) { 1696 /* Exception. Bailout! */ 1697 if (!copied) 1698 copied = -EFAULT; 1699 break; 1700 } 1701 } 1702 } 1703 1704 *seq += used; 1705 copied += used; 1706 len -= used; 1707 1708 tcp_rcv_space_adjust(sk); 1709 1710 skip_copy: 1711 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1712 tp->urg_data = 0; 1713 tcp_fast_path_check(sk); 1714 } 1715 if (used + offset < skb->len) 1716 continue; 1717 1718 if (tcp_hdr(skb)->fin) 1719 goto found_fin_ok; 1720 if (!(flags & MSG_PEEK)) { 1721 sk_eat_skb(sk, skb, copied_early); 1722 copied_early = 0; 1723 } 1724 continue; 1725 1726 found_fin_ok: 1727 /* Process the FIN. */ 1728 ++*seq; 1729 if (!(flags & MSG_PEEK)) { 1730 sk_eat_skb(sk, skb, copied_early); 1731 copied_early = 0; 1732 } 1733 break; 1734 } while (len > 0); 1735 1736 if (user_recv) { 1737 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1738 int chunk; 1739 1740 tp->ucopy.len = copied > 0 ? len : 0; 1741 1742 tcp_prequeue_process(sk); 1743 1744 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1745 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1746 len -= chunk; 1747 copied += chunk; 1748 } 1749 } 1750 1751 tp->ucopy.task = NULL; 1752 tp->ucopy.len = 0; 1753 } 1754 1755 #ifdef CONFIG_NET_DMA 1756 tcp_service_net_dma(sk, true); /* Wait for queue to drain */ 1757 tp->ucopy.dma_chan = NULL; 1758 1759 if (tp->ucopy.pinned_list) { 1760 dma_unpin_iovec_pages(tp->ucopy.pinned_list); 1761 tp->ucopy.pinned_list = NULL; 1762 } 1763 #endif 1764 1765 /* According to UNIX98, msg_name/msg_namelen are ignored 1766 * on connected socket. I was just happy when found this 8) --ANK 1767 */ 1768 1769 /* Clean up data we have read: This will do ACK frames. */ 1770 tcp_cleanup_rbuf(sk, copied); 1771 1772 release_sock(sk); 1773 return copied; 1774 1775 out: 1776 release_sock(sk); 1777 return err; 1778 1779 recv_urg: 1780 err = tcp_recv_urg(sk, msg, len, flags); 1781 goto out; 1782 } 1783 EXPORT_SYMBOL(tcp_recvmsg); 1784 1785 void tcp_set_state(struct sock *sk, int state) 1786 { 1787 int oldstate = sk->sk_state; 1788 1789 switch (state) { 1790 case TCP_ESTABLISHED: 1791 if (oldstate != TCP_ESTABLISHED) 1792 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1793 break; 1794 1795 case TCP_CLOSE: 1796 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 1797 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS); 1798 1799 sk->sk_prot->unhash(sk); 1800 if (inet_csk(sk)->icsk_bind_hash && 1801 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 1802 inet_put_port(sk); 1803 /* fall through */ 1804 default: 1805 if (oldstate == TCP_ESTABLISHED) 1806 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1807 } 1808 1809 /* Change state AFTER socket is unhashed to avoid closed 1810 * socket sitting in hash tables. 1811 */ 1812 sk->sk_state = state; 1813 1814 #ifdef STATE_TRACE 1815 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]); 1816 #endif 1817 } 1818 EXPORT_SYMBOL_GPL(tcp_set_state); 1819 1820 /* 1821 * State processing on a close. This implements the state shift for 1822 * sending our FIN frame. Note that we only send a FIN for some 1823 * states. A shutdown() may have already sent the FIN, or we may be 1824 * closed. 1825 */ 1826 1827 static const unsigned char new_state[16] = { 1828 /* current state: new state: action: */ 1829 /* (Invalid) */ TCP_CLOSE, 1830 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1831 /* TCP_SYN_SENT */ TCP_CLOSE, 1832 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1833 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, 1834 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, 1835 /* TCP_TIME_WAIT */ TCP_CLOSE, 1836 /* TCP_CLOSE */ TCP_CLOSE, 1837 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, 1838 /* TCP_LAST_ACK */ TCP_LAST_ACK, 1839 /* TCP_LISTEN */ TCP_CLOSE, 1840 /* TCP_CLOSING */ TCP_CLOSING, 1841 }; 1842 1843 static int tcp_close_state(struct sock *sk) 1844 { 1845 int next = (int)new_state[sk->sk_state]; 1846 int ns = next & TCP_STATE_MASK; 1847 1848 tcp_set_state(sk, ns); 1849 1850 return next & TCP_ACTION_FIN; 1851 } 1852 1853 /* 1854 * Shutdown the sending side of a connection. Much like close except 1855 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD). 1856 */ 1857 1858 void tcp_shutdown(struct sock *sk, int how) 1859 { 1860 /* We need to grab some memory, and put together a FIN, 1861 * and then put it into the queue to be sent. 1862 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 1863 */ 1864 if (!(how & SEND_SHUTDOWN)) 1865 return; 1866 1867 /* If we've already sent a FIN, or it's a closed state, skip this. */ 1868 if ((1 << sk->sk_state) & 1869 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 1870 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 1871 /* Clear out any half completed packets. FIN if needed. */ 1872 if (tcp_close_state(sk)) 1873 tcp_send_fin(sk); 1874 } 1875 } 1876 EXPORT_SYMBOL(tcp_shutdown); 1877 1878 void tcp_close(struct sock *sk, long timeout) 1879 { 1880 struct sk_buff *skb; 1881 int data_was_unread = 0; 1882 int state; 1883 1884 lock_sock(sk); 1885 sk->sk_shutdown = SHUTDOWN_MASK; 1886 1887 if (sk->sk_state == TCP_LISTEN) { 1888 tcp_set_state(sk, TCP_CLOSE); 1889 1890 /* Special case. */ 1891 inet_csk_listen_stop(sk); 1892 1893 goto adjudge_to_death; 1894 } 1895 1896 /* We need to flush the recv. buffs. We do this only on the 1897 * descriptor close, not protocol-sourced closes, because the 1898 * reader process may not have drained the data yet! 1899 */ 1900 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 1901 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq - 1902 tcp_hdr(skb)->fin; 1903 data_was_unread += len; 1904 __kfree_skb(skb); 1905 } 1906 1907 sk_mem_reclaim(sk); 1908 1909 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */ 1910 if (sk->sk_state == TCP_CLOSE) 1911 goto adjudge_to_death; 1912 1913 /* As outlined in RFC 2525, section 2.17, we send a RST here because 1914 * data was lost. To witness the awful effects of the old behavior of 1915 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk 1916 * GET in an FTP client, suspend the process, wait for the client to 1917 * advertise a zero window, then kill -9 the FTP client, wheee... 1918 * Note: timeout is always zero in such a case. 1919 */ 1920 if (data_was_unread) { 1921 /* Unread data was tossed, zap the connection. */ 1922 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE); 1923 tcp_set_state(sk, TCP_CLOSE); 1924 tcp_send_active_reset(sk, sk->sk_allocation); 1925 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 1926 /* Check zero linger _after_ checking for unread data. */ 1927 sk->sk_prot->disconnect(sk, 0); 1928 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA); 1929 } else if (tcp_close_state(sk)) { 1930 /* We FIN if the application ate all the data before 1931 * zapping the connection. 1932 */ 1933 1934 /* RED-PEN. Formally speaking, we have broken TCP state 1935 * machine. State transitions: 1936 * 1937 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 1938 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 1939 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 1940 * 1941 * are legal only when FIN has been sent (i.e. in window), 1942 * rather than queued out of window. Purists blame. 1943 * 1944 * F.e. "RFC state" is ESTABLISHED, 1945 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 1946 * 1947 * The visible declinations are that sometimes 1948 * we enter time-wait state, when it is not required really 1949 * (harmless), do not send active resets, when they are 1950 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 1951 * they look as CLOSING or LAST_ACK for Linux) 1952 * Probably, I missed some more holelets. 1953 * --ANK 1954 */ 1955 tcp_send_fin(sk); 1956 } 1957 1958 sk_stream_wait_close(sk, timeout); 1959 1960 adjudge_to_death: 1961 state = sk->sk_state; 1962 sock_hold(sk); 1963 sock_orphan(sk); 1964 1965 /* It is the last release_sock in its life. It will remove backlog. */ 1966 release_sock(sk); 1967 1968 1969 /* Now socket is owned by kernel and we acquire BH lock 1970 to finish close. No need to check for user refs. 1971 */ 1972 local_bh_disable(); 1973 bh_lock_sock(sk); 1974 WARN_ON(sock_owned_by_user(sk)); 1975 1976 percpu_counter_inc(sk->sk_prot->orphan_count); 1977 1978 /* Have we already been destroyed by a softirq or backlog? */ 1979 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) 1980 goto out; 1981 1982 /* This is a (useful) BSD violating of the RFC. There is a 1983 * problem with TCP as specified in that the other end could 1984 * keep a socket open forever with no application left this end. 1985 * We use a 3 minute timeout (about the same as BSD) then kill 1986 * our end. If they send after that then tough - BUT: long enough 1987 * that we won't make the old 4*rto = almost no time - whoops 1988 * reset mistake. 1989 * 1990 * Nope, it was not mistake. It is really desired behaviour 1991 * f.e. on http servers, when such sockets are useless, but 1992 * consume significant resources. Let's do it with special 1993 * linger2 option. --ANK 1994 */ 1995 1996 if (sk->sk_state == TCP_FIN_WAIT2) { 1997 struct tcp_sock *tp = tcp_sk(sk); 1998 if (tp->linger2 < 0) { 1999 tcp_set_state(sk, TCP_CLOSE); 2000 tcp_send_active_reset(sk, GFP_ATOMIC); 2001 NET_INC_STATS_BH(sock_net(sk), 2002 LINUX_MIB_TCPABORTONLINGER); 2003 } else { 2004 const int tmo = tcp_fin_time(sk); 2005 2006 if (tmo > TCP_TIMEWAIT_LEN) { 2007 inet_csk_reset_keepalive_timer(sk, 2008 tmo - TCP_TIMEWAIT_LEN); 2009 } else { 2010 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); 2011 goto out; 2012 } 2013 } 2014 } 2015 if (sk->sk_state != TCP_CLOSE) { 2016 sk_mem_reclaim(sk); 2017 if (tcp_too_many_orphans(sk, 0)) { 2018 if (net_ratelimit()) 2019 printk(KERN_INFO "TCP: too many of orphaned " 2020 "sockets\n"); 2021 tcp_set_state(sk, TCP_CLOSE); 2022 tcp_send_active_reset(sk, GFP_ATOMIC); 2023 NET_INC_STATS_BH(sock_net(sk), 2024 LINUX_MIB_TCPABORTONMEMORY); 2025 } 2026 } 2027 2028 if (sk->sk_state == TCP_CLOSE) 2029 inet_csk_destroy_sock(sk); 2030 /* Otherwise, socket is reprieved until protocol close. */ 2031 2032 out: 2033 bh_unlock_sock(sk); 2034 local_bh_enable(); 2035 sock_put(sk); 2036 } 2037 EXPORT_SYMBOL(tcp_close); 2038 2039 /* These states need RST on ABORT according to RFC793 */ 2040 2041 static inline int tcp_need_reset(int state) 2042 { 2043 return (1 << state) & 2044 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 2045 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 2046 } 2047 2048 int tcp_disconnect(struct sock *sk, int flags) 2049 { 2050 struct inet_sock *inet = inet_sk(sk); 2051 struct inet_connection_sock *icsk = inet_csk(sk); 2052 struct tcp_sock *tp = tcp_sk(sk); 2053 int err = 0; 2054 int old_state = sk->sk_state; 2055 2056 if (old_state != TCP_CLOSE) 2057 tcp_set_state(sk, TCP_CLOSE); 2058 2059 /* ABORT function of RFC793 */ 2060 if (old_state == TCP_LISTEN) { 2061 inet_csk_listen_stop(sk); 2062 } else if (tcp_need_reset(old_state) || 2063 (tp->snd_nxt != tp->write_seq && 2064 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 2065 /* The last check adjusts for discrepancy of Linux wrt. RFC 2066 * states 2067 */ 2068 tcp_send_active_reset(sk, gfp_any()); 2069 sk->sk_err = ECONNRESET; 2070 } else if (old_state == TCP_SYN_SENT) 2071 sk->sk_err = ECONNRESET; 2072 2073 tcp_clear_xmit_timers(sk); 2074 __skb_queue_purge(&sk->sk_receive_queue); 2075 tcp_write_queue_purge(sk); 2076 __skb_queue_purge(&tp->out_of_order_queue); 2077 #ifdef CONFIG_NET_DMA 2078 __skb_queue_purge(&sk->sk_async_wait_queue); 2079 #endif 2080 2081 inet->inet_dport = 0; 2082 2083 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 2084 inet_reset_saddr(sk); 2085 2086 sk->sk_shutdown = 0; 2087 sock_reset_flag(sk, SOCK_DONE); 2088 tp->srtt = 0; 2089 if ((tp->write_seq += tp->max_window + 2) == 0) 2090 tp->write_seq = 1; 2091 icsk->icsk_backoff = 0; 2092 tp->snd_cwnd = 2; 2093 icsk->icsk_probes_out = 0; 2094 tp->packets_out = 0; 2095 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 2096 tp->snd_cwnd_cnt = 0; 2097 tp->bytes_acked = 0; 2098 tp->window_clamp = 0; 2099 tcp_set_ca_state(sk, TCP_CA_Open); 2100 tcp_clear_retrans(tp); 2101 inet_csk_delack_init(sk); 2102 tcp_init_send_head(sk); 2103 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); 2104 __sk_dst_reset(sk); 2105 2106 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash); 2107 2108 sk->sk_error_report(sk); 2109 return err; 2110 } 2111 EXPORT_SYMBOL(tcp_disconnect); 2112 2113 /* 2114 * Socket option code for TCP. 2115 */ 2116 static int do_tcp_setsockopt(struct sock *sk, int level, 2117 int optname, char __user *optval, unsigned int optlen) 2118 { 2119 struct tcp_sock *tp = tcp_sk(sk); 2120 struct inet_connection_sock *icsk = inet_csk(sk); 2121 int val; 2122 int err = 0; 2123 2124 /* These are data/string values, all the others are ints */ 2125 switch (optname) { 2126 case TCP_CONGESTION: { 2127 char name[TCP_CA_NAME_MAX]; 2128 2129 if (optlen < 1) 2130 return -EINVAL; 2131 2132 val = strncpy_from_user(name, optval, 2133 min_t(long, TCP_CA_NAME_MAX-1, optlen)); 2134 if (val < 0) 2135 return -EFAULT; 2136 name[val] = 0; 2137 2138 lock_sock(sk); 2139 err = tcp_set_congestion_control(sk, name); 2140 release_sock(sk); 2141 return err; 2142 } 2143 case TCP_COOKIE_TRANSACTIONS: { 2144 struct tcp_cookie_transactions ctd; 2145 struct tcp_cookie_values *cvp = NULL; 2146 2147 if (sizeof(ctd) > optlen) 2148 return -EINVAL; 2149 if (copy_from_user(&ctd, optval, sizeof(ctd))) 2150 return -EFAULT; 2151 2152 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) || 2153 ctd.tcpct_s_data_desired > TCP_MSS_DESIRED) 2154 return -EINVAL; 2155 2156 if (ctd.tcpct_cookie_desired == 0) { 2157 /* default to global value */ 2158 } else if ((0x1 & ctd.tcpct_cookie_desired) || 2159 ctd.tcpct_cookie_desired > TCP_COOKIE_MAX || 2160 ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) { 2161 return -EINVAL; 2162 } 2163 2164 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) { 2165 /* Supercedes all other values */ 2166 lock_sock(sk); 2167 if (tp->cookie_values != NULL) { 2168 kref_put(&tp->cookie_values->kref, 2169 tcp_cookie_values_release); 2170 tp->cookie_values = NULL; 2171 } 2172 tp->rx_opt.cookie_in_always = 0; /* false */ 2173 tp->rx_opt.cookie_out_never = 1; /* true */ 2174 release_sock(sk); 2175 return err; 2176 } 2177 2178 /* Allocate ancillary memory before locking. 2179 */ 2180 if (ctd.tcpct_used > 0 || 2181 (tp->cookie_values == NULL && 2182 (sysctl_tcp_cookie_size > 0 || 2183 ctd.tcpct_cookie_desired > 0 || 2184 ctd.tcpct_s_data_desired > 0))) { 2185 cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used, 2186 GFP_KERNEL); 2187 if (cvp == NULL) 2188 return -ENOMEM; 2189 2190 kref_init(&cvp->kref); 2191 } 2192 lock_sock(sk); 2193 tp->rx_opt.cookie_in_always = 2194 (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags); 2195 tp->rx_opt.cookie_out_never = 0; /* false */ 2196 2197 if (tp->cookie_values != NULL) { 2198 if (cvp != NULL) { 2199 /* Changed values are recorded by a changed 2200 * pointer, ensuring the cookie will differ, 2201 * without separately hashing each value later. 2202 */ 2203 kref_put(&tp->cookie_values->kref, 2204 tcp_cookie_values_release); 2205 } else { 2206 cvp = tp->cookie_values; 2207 } 2208 } 2209 2210 if (cvp != NULL) { 2211 cvp->cookie_desired = ctd.tcpct_cookie_desired; 2212 2213 if (ctd.tcpct_used > 0) { 2214 memcpy(cvp->s_data_payload, ctd.tcpct_value, 2215 ctd.tcpct_used); 2216 cvp->s_data_desired = ctd.tcpct_used; 2217 cvp->s_data_constant = 1; /* true */ 2218 } else { 2219 /* No constant payload data. */ 2220 cvp->s_data_desired = ctd.tcpct_s_data_desired; 2221 cvp->s_data_constant = 0; /* false */ 2222 } 2223 2224 tp->cookie_values = cvp; 2225 } 2226 release_sock(sk); 2227 return err; 2228 } 2229 default: 2230 /* fallthru */ 2231 break; 2232 } 2233 2234 if (optlen < sizeof(int)) 2235 return -EINVAL; 2236 2237 if (get_user(val, (int __user *)optval)) 2238 return -EFAULT; 2239 2240 lock_sock(sk); 2241 2242 switch (optname) { 2243 case TCP_MAXSEG: 2244 /* Values greater than interface MTU won't take effect. However 2245 * at the point when this call is done we typically don't yet 2246 * know which interface is going to be used */ 2247 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) { 2248 err = -EINVAL; 2249 break; 2250 } 2251 tp->rx_opt.user_mss = val; 2252 break; 2253 2254 case TCP_NODELAY: 2255 if (val) { 2256 /* TCP_NODELAY is weaker than TCP_CORK, so that 2257 * this option on corked socket is remembered, but 2258 * it is not activated until cork is cleared. 2259 * 2260 * However, when TCP_NODELAY is set we make 2261 * an explicit push, which overrides even TCP_CORK 2262 * for currently queued segments. 2263 */ 2264 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 2265 tcp_push_pending_frames(sk); 2266 } else { 2267 tp->nonagle &= ~TCP_NAGLE_OFF; 2268 } 2269 break; 2270 2271 case TCP_THIN_LINEAR_TIMEOUTS: 2272 if (val < 0 || val > 1) 2273 err = -EINVAL; 2274 else 2275 tp->thin_lto = val; 2276 break; 2277 2278 case TCP_THIN_DUPACK: 2279 if (val < 0 || val > 1) 2280 err = -EINVAL; 2281 else 2282 tp->thin_dupack = val; 2283 break; 2284 2285 case TCP_CORK: 2286 /* When set indicates to always queue non-full frames. 2287 * Later the user clears this option and we transmit 2288 * any pending partial frames in the queue. This is 2289 * meant to be used alongside sendfile() to get properly 2290 * filled frames when the user (for example) must write 2291 * out headers with a write() call first and then use 2292 * sendfile to send out the data parts. 2293 * 2294 * TCP_CORK can be set together with TCP_NODELAY and it is 2295 * stronger than TCP_NODELAY. 2296 */ 2297 if (val) { 2298 tp->nonagle |= TCP_NAGLE_CORK; 2299 } else { 2300 tp->nonagle &= ~TCP_NAGLE_CORK; 2301 if (tp->nonagle&TCP_NAGLE_OFF) 2302 tp->nonagle |= TCP_NAGLE_PUSH; 2303 tcp_push_pending_frames(sk); 2304 } 2305 break; 2306 2307 case TCP_KEEPIDLE: 2308 if (val < 1 || val > MAX_TCP_KEEPIDLE) 2309 err = -EINVAL; 2310 else { 2311 tp->keepalive_time = val * HZ; 2312 if (sock_flag(sk, SOCK_KEEPOPEN) && 2313 !((1 << sk->sk_state) & 2314 (TCPF_CLOSE | TCPF_LISTEN))) { 2315 u32 elapsed = keepalive_time_elapsed(tp); 2316 if (tp->keepalive_time > elapsed) 2317 elapsed = tp->keepalive_time - elapsed; 2318 else 2319 elapsed = 0; 2320 inet_csk_reset_keepalive_timer(sk, elapsed); 2321 } 2322 } 2323 break; 2324 case TCP_KEEPINTVL: 2325 if (val < 1 || val > MAX_TCP_KEEPINTVL) 2326 err = -EINVAL; 2327 else 2328 tp->keepalive_intvl = val * HZ; 2329 break; 2330 case TCP_KEEPCNT: 2331 if (val < 1 || val > MAX_TCP_KEEPCNT) 2332 err = -EINVAL; 2333 else 2334 tp->keepalive_probes = val; 2335 break; 2336 case TCP_SYNCNT: 2337 if (val < 1 || val > MAX_TCP_SYNCNT) 2338 err = -EINVAL; 2339 else 2340 icsk->icsk_syn_retries = val; 2341 break; 2342 2343 case TCP_LINGER2: 2344 if (val < 0) 2345 tp->linger2 = -1; 2346 else if (val > sysctl_tcp_fin_timeout / HZ) 2347 tp->linger2 = 0; 2348 else 2349 tp->linger2 = val * HZ; 2350 break; 2351 2352 case TCP_DEFER_ACCEPT: 2353 /* Translate value in seconds to number of retransmits */ 2354 icsk->icsk_accept_queue.rskq_defer_accept = 2355 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ, 2356 TCP_RTO_MAX / HZ); 2357 break; 2358 2359 case TCP_WINDOW_CLAMP: 2360 if (!val) { 2361 if (sk->sk_state != TCP_CLOSE) { 2362 err = -EINVAL; 2363 break; 2364 } 2365 tp->window_clamp = 0; 2366 } else 2367 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 2368 SOCK_MIN_RCVBUF / 2 : val; 2369 break; 2370 2371 case TCP_QUICKACK: 2372 if (!val) { 2373 icsk->icsk_ack.pingpong = 1; 2374 } else { 2375 icsk->icsk_ack.pingpong = 0; 2376 if ((1 << sk->sk_state) & 2377 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 2378 inet_csk_ack_scheduled(sk)) { 2379 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 2380 tcp_cleanup_rbuf(sk, 1); 2381 if (!(val & 1)) 2382 icsk->icsk_ack.pingpong = 1; 2383 } 2384 } 2385 break; 2386 2387 #ifdef CONFIG_TCP_MD5SIG 2388 case TCP_MD5SIG: 2389 /* Read the IP->Key mappings from userspace */ 2390 err = tp->af_specific->md5_parse(sk, optval, optlen); 2391 break; 2392 #endif 2393 case TCP_USER_TIMEOUT: 2394 /* Cap the max timeout in ms TCP will retry/retrans 2395 * before giving up and aborting (ETIMEDOUT) a connection. 2396 */ 2397 icsk->icsk_user_timeout = msecs_to_jiffies(val); 2398 break; 2399 default: 2400 err = -ENOPROTOOPT; 2401 break; 2402 } 2403 2404 release_sock(sk); 2405 return err; 2406 } 2407 2408 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 2409 unsigned int optlen) 2410 { 2411 struct inet_connection_sock *icsk = inet_csk(sk); 2412 2413 if (level != SOL_TCP) 2414 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 2415 optval, optlen); 2416 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2417 } 2418 EXPORT_SYMBOL(tcp_setsockopt); 2419 2420 #ifdef CONFIG_COMPAT 2421 int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 2422 char __user *optval, unsigned int optlen) 2423 { 2424 if (level != SOL_TCP) 2425 return inet_csk_compat_setsockopt(sk, level, optname, 2426 optval, optlen); 2427 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2428 } 2429 EXPORT_SYMBOL(compat_tcp_setsockopt); 2430 #endif 2431 2432 /* Return information about state of tcp endpoint in API format. */ 2433 void tcp_get_info(struct sock *sk, struct tcp_info *info) 2434 { 2435 struct tcp_sock *tp = tcp_sk(sk); 2436 const struct inet_connection_sock *icsk = inet_csk(sk); 2437 u32 now = tcp_time_stamp; 2438 2439 memset(info, 0, sizeof(*info)); 2440 2441 info->tcpi_state = sk->sk_state; 2442 info->tcpi_ca_state = icsk->icsk_ca_state; 2443 info->tcpi_retransmits = icsk->icsk_retransmits; 2444 info->tcpi_probes = icsk->icsk_probes_out; 2445 info->tcpi_backoff = icsk->icsk_backoff; 2446 2447 if (tp->rx_opt.tstamp_ok) 2448 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2449 if (tcp_is_sack(tp)) 2450 info->tcpi_options |= TCPI_OPT_SACK; 2451 if (tp->rx_opt.wscale_ok) { 2452 info->tcpi_options |= TCPI_OPT_WSCALE; 2453 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2454 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2455 } 2456 2457 if (tp->ecn_flags&TCP_ECN_OK) 2458 info->tcpi_options |= TCPI_OPT_ECN; 2459 2460 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2461 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2462 info->tcpi_snd_mss = tp->mss_cache; 2463 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2464 2465 if (sk->sk_state == TCP_LISTEN) { 2466 info->tcpi_unacked = sk->sk_ack_backlog; 2467 info->tcpi_sacked = sk->sk_max_ack_backlog; 2468 } else { 2469 info->tcpi_unacked = tp->packets_out; 2470 info->tcpi_sacked = tp->sacked_out; 2471 } 2472 info->tcpi_lost = tp->lost_out; 2473 info->tcpi_retrans = tp->retrans_out; 2474 info->tcpi_fackets = tp->fackets_out; 2475 2476 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2477 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2478 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2479 2480 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2481 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2482 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3; 2483 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2; 2484 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2485 info->tcpi_snd_cwnd = tp->snd_cwnd; 2486 info->tcpi_advmss = tp->advmss; 2487 info->tcpi_reordering = tp->reordering; 2488 2489 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2490 info->tcpi_rcv_space = tp->rcvq_space.space; 2491 2492 info->tcpi_total_retrans = tp->total_retrans; 2493 } 2494 EXPORT_SYMBOL_GPL(tcp_get_info); 2495 2496 static int do_tcp_getsockopt(struct sock *sk, int level, 2497 int optname, char __user *optval, int __user *optlen) 2498 { 2499 struct inet_connection_sock *icsk = inet_csk(sk); 2500 struct tcp_sock *tp = tcp_sk(sk); 2501 int val, len; 2502 2503 if (get_user(len, optlen)) 2504 return -EFAULT; 2505 2506 len = min_t(unsigned int, len, sizeof(int)); 2507 2508 if (len < 0) 2509 return -EINVAL; 2510 2511 switch (optname) { 2512 case TCP_MAXSEG: 2513 val = tp->mss_cache; 2514 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2515 val = tp->rx_opt.user_mss; 2516 break; 2517 case TCP_NODELAY: 2518 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2519 break; 2520 case TCP_CORK: 2521 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2522 break; 2523 case TCP_KEEPIDLE: 2524 val = keepalive_time_when(tp) / HZ; 2525 break; 2526 case TCP_KEEPINTVL: 2527 val = keepalive_intvl_when(tp) / HZ; 2528 break; 2529 case TCP_KEEPCNT: 2530 val = keepalive_probes(tp); 2531 break; 2532 case TCP_SYNCNT: 2533 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2534 break; 2535 case TCP_LINGER2: 2536 val = tp->linger2; 2537 if (val >= 0) 2538 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2539 break; 2540 case TCP_DEFER_ACCEPT: 2541 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept, 2542 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ); 2543 break; 2544 case TCP_WINDOW_CLAMP: 2545 val = tp->window_clamp; 2546 break; 2547 case TCP_INFO: { 2548 struct tcp_info info; 2549 2550 if (get_user(len, optlen)) 2551 return -EFAULT; 2552 2553 tcp_get_info(sk, &info); 2554 2555 len = min_t(unsigned int, len, sizeof(info)); 2556 if (put_user(len, optlen)) 2557 return -EFAULT; 2558 if (copy_to_user(optval, &info, len)) 2559 return -EFAULT; 2560 return 0; 2561 } 2562 case TCP_QUICKACK: 2563 val = !icsk->icsk_ack.pingpong; 2564 break; 2565 2566 case TCP_CONGESTION: 2567 if (get_user(len, optlen)) 2568 return -EFAULT; 2569 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2570 if (put_user(len, optlen)) 2571 return -EFAULT; 2572 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2573 return -EFAULT; 2574 return 0; 2575 2576 case TCP_COOKIE_TRANSACTIONS: { 2577 struct tcp_cookie_transactions ctd; 2578 struct tcp_cookie_values *cvp = tp->cookie_values; 2579 2580 if (get_user(len, optlen)) 2581 return -EFAULT; 2582 if (len < sizeof(ctd)) 2583 return -EINVAL; 2584 2585 memset(&ctd, 0, sizeof(ctd)); 2586 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ? 2587 TCP_COOKIE_IN_ALWAYS : 0) 2588 | (tp->rx_opt.cookie_out_never ? 2589 TCP_COOKIE_OUT_NEVER : 0); 2590 2591 if (cvp != NULL) { 2592 ctd.tcpct_flags |= (cvp->s_data_in ? 2593 TCP_S_DATA_IN : 0) 2594 | (cvp->s_data_out ? 2595 TCP_S_DATA_OUT : 0); 2596 2597 ctd.tcpct_cookie_desired = cvp->cookie_desired; 2598 ctd.tcpct_s_data_desired = cvp->s_data_desired; 2599 2600 memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0], 2601 cvp->cookie_pair_size); 2602 ctd.tcpct_used = cvp->cookie_pair_size; 2603 } 2604 2605 if (put_user(sizeof(ctd), optlen)) 2606 return -EFAULT; 2607 if (copy_to_user(optval, &ctd, sizeof(ctd))) 2608 return -EFAULT; 2609 return 0; 2610 } 2611 case TCP_THIN_LINEAR_TIMEOUTS: 2612 val = tp->thin_lto; 2613 break; 2614 case TCP_THIN_DUPACK: 2615 val = tp->thin_dupack; 2616 break; 2617 2618 case TCP_USER_TIMEOUT: 2619 val = jiffies_to_msecs(icsk->icsk_user_timeout); 2620 break; 2621 default: 2622 return -ENOPROTOOPT; 2623 } 2624 2625 if (put_user(len, optlen)) 2626 return -EFAULT; 2627 if (copy_to_user(optval, &val, len)) 2628 return -EFAULT; 2629 return 0; 2630 } 2631 2632 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2633 int __user *optlen) 2634 { 2635 struct inet_connection_sock *icsk = inet_csk(sk); 2636 2637 if (level != SOL_TCP) 2638 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2639 optval, optlen); 2640 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2641 } 2642 EXPORT_SYMBOL(tcp_getsockopt); 2643 2644 #ifdef CONFIG_COMPAT 2645 int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2646 char __user *optval, int __user *optlen) 2647 { 2648 if (level != SOL_TCP) 2649 return inet_csk_compat_getsockopt(sk, level, optname, 2650 optval, optlen); 2651 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2652 } 2653 EXPORT_SYMBOL(compat_tcp_getsockopt); 2654 #endif 2655 2656 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, u32 features) 2657 { 2658 struct sk_buff *segs = ERR_PTR(-EINVAL); 2659 struct tcphdr *th; 2660 unsigned thlen; 2661 unsigned int seq; 2662 __be32 delta; 2663 unsigned int oldlen; 2664 unsigned int mss; 2665 2666 if (!pskb_may_pull(skb, sizeof(*th))) 2667 goto out; 2668 2669 th = tcp_hdr(skb); 2670 thlen = th->doff * 4; 2671 if (thlen < sizeof(*th)) 2672 goto out; 2673 2674 if (!pskb_may_pull(skb, thlen)) 2675 goto out; 2676 2677 oldlen = (u16)~skb->len; 2678 __skb_pull(skb, thlen); 2679 2680 mss = skb_shinfo(skb)->gso_size; 2681 if (unlikely(skb->len <= mss)) 2682 goto out; 2683 2684 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 2685 /* Packet is from an untrusted source, reset gso_segs. */ 2686 int type = skb_shinfo(skb)->gso_type; 2687 2688 if (unlikely(type & 2689 ~(SKB_GSO_TCPV4 | 2690 SKB_GSO_DODGY | 2691 SKB_GSO_TCP_ECN | 2692 SKB_GSO_TCPV6 | 2693 0) || 2694 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) 2695 goto out; 2696 2697 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); 2698 2699 segs = NULL; 2700 goto out; 2701 } 2702 2703 segs = skb_segment(skb, features); 2704 if (IS_ERR(segs)) 2705 goto out; 2706 2707 delta = htonl(oldlen + (thlen + mss)); 2708 2709 skb = segs; 2710 th = tcp_hdr(skb); 2711 seq = ntohl(th->seq); 2712 2713 do { 2714 th->fin = th->psh = 0; 2715 2716 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2717 (__force u32)delta)); 2718 if (skb->ip_summed != CHECKSUM_PARTIAL) 2719 th->check = 2720 csum_fold(csum_partial(skb_transport_header(skb), 2721 thlen, skb->csum)); 2722 2723 seq += mss; 2724 skb = skb->next; 2725 th = tcp_hdr(skb); 2726 2727 th->seq = htonl(seq); 2728 th->cwr = 0; 2729 } while (skb->next); 2730 2731 delta = htonl(oldlen + (skb->tail - skb->transport_header) + 2732 skb->data_len); 2733 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2734 (__force u32)delta)); 2735 if (skb->ip_summed != CHECKSUM_PARTIAL) 2736 th->check = csum_fold(csum_partial(skb_transport_header(skb), 2737 thlen, skb->csum)); 2738 2739 out: 2740 return segs; 2741 } 2742 EXPORT_SYMBOL(tcp_tso_segment); 2743 2744 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) 2745 { 2746 struct sk_buff **pp = NULL; 2747 struct sk_buff *p; 2748 struct tcphdr *th; 2749 struct tcphdr *th2; 2750 unsigned int len; 2751 unsigned int thlen; 2752 __be32 flags; 2753 unsigned int mss = 1; 2754 unsigned int hlen; 2755 unsigned int off; 2756 int flush = 1; 2757 int i; 2758 2759 off = skb_gro_offset(skb); 2760 hlen = off + sizeof(*th); 2761 th = skb_gro_header_fast(skb, off); 2762 if (skb_gro_header_hard(skb, hlen)) { 2763 th = skb_gro_header_slow(skb, hlen, off); 2764 if (unlikely(!th)) 2765 goto out; 2766 } 2767 2768 thlen = th->doff * 4; 2769 if (thlen < sizeof(*th)) 2770 goto out; 2771 2772 hlen = off + thlen; 2773 if (skb_gro_header_hard(skb, hlen)) { 2774 th = skb_gro_header_slow(skb, hlen, off); 2775 if (unlikely(!th)) 2776 goto out; 2777 } 2778 2779 skb_gro_pull(skb, thlen); 2780 2781 len = skb_gro_len(skb); 2782 flags = tcp_flag_word(th); 2783 2784 for (; (p = *head); head = &p->next) { 2785 if (!NAPI_GRO_CB(p)->same_flow) 2786 continue; 2787 2788 th2 = tcp_hdr(p); 2789 2790 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) { 2791 NAPI_GRO_CB(p)->same_flow = 0; 2792 continue; 2793 } 2794 2795 goto found; 2796 } 2797 2798 goto out_check_final; 2799 2800 found: 2801 flush = NAPI_GRO_CB(p)->flush; 2802 flush |= (__force int)(flags & TCP_FLAG_CWR); 2803 flush |= (__force int)((flags ^ tcp_flag_word(th2)) & 2804 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); 2805 flush |= (__force int)(th->ack_seq ^ th2->ack_seq); 2806 for (i = sizeof(*th); i < thlen; i += 4) 2807 flush |= *(u32 *)((u8 *)th + i) ^ 2808 *(u32 *)((u8 *)th2 + i); 2809 2810 mss = skb_shinfo(p)->gso_size; 2811 2812 flush |= (len - 1) >= mss; 2813 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); 2814 2815 if (flush || skb_gro_receive(head, skb)) { 2816 mss = 1; 2817 goto out_check_final; 2818 } 2819 2820 p = *head; 2821 th2 = tcp_hdr(p); 2822 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); 2823 2824 out_check_final: 2825 flush = len < mss; 2826 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH | 2827 TCP_FLAG_RST | TCP_FLAG_SYN | 2828 TCP_FLAG_FIN)); 2829 2830 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) 2831 pp = head; 2832 2833 out: 2834 NAPI_GRO_CB(skb)->flush |= flush; 2835 2836 return pp; 2837 } 2838 EXPORT_SYMBOL(tcp_gro_receive); 2839 2840 int tcp_gro_complete(struct sk_buff *skb) 2841 { 2842 struct tcphdr *th = tcp_hdr(skb); 2843 2844 skb->csum_start = skb_transport_header(skb) - skb->head; 2845 skb->csum_offset = offsetof(struct tcphdr, check); 2846 skb->ip_summed = CHECKSUM_PARTIAL; 2847 2848 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 2849 2850 if (th->cwr) 2851 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 2852 2853 return 0; 2854 } 2855 EXPORT_SYMBOL(tcp_gro_complete); 2856 2857 #ifdef CONFIG_TCP_MD5SIG 2858 static unsigned long tcp_md5sig_users; 2859 static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool; 2860 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock); 2861 2862 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool) 2863 { 2864 int cpu; 2865 for_each_possible_cpu(cpu) { 2866 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu); 2867 if (p) { 2868 if (p->md5_desc.tfm) 2869 crypto_free_hash(p->md5_desc.tfm); 2870 kfree(p); 2871 } 2872 } 2873 free_percpu(pool); 2874 } 2875 2876 void tcp_free_md5sig_pool(void) 2877 { 2878 struct tcp_md5sig_pool * __percpu *pool = NULL; 2879 2880 spin_lock_bh(&tcp_md5sig_pool_lock); 2881 if (--tcp_md5sig_users == 0) { 2882 pool = tcp_md5sig_pool; 2883 tcp_md5sig_pool = NULL; 2884 } 2885 spin_unlock_bh(&tcp_md5sig_pool_lock); 2886 if (pool) 2887 __tcp_free_md5sig_pool(pool); 2888 } 2889 EXPORT_SYMBOL(tcp_free_md5sig_pool); 2890 2891 static struct tcp_md5sig_pool * __percpu * 2892 __tcp_alloc_md5sig_pool(struct sock *sk) 2893 { 2894 int cpu; 2895 struct tcp_md5sig_pool * __percpu *pool; 2896 2897 pool = alloc_percpu(struct tcp_md5sig_pool *); 2898 if (!pool) 2899 return NULL; 2900 2901 for_each_possible_cpu(cpu) { 2902 struct tcp_md5sig_pool *p; 2903 struct crypto_hash *hash; 2904 2905 p = kzalloc(sizeof(*p), sk->sk_allocation); 2906 if (!p) 2907 goto out_free; 2908 *per_cpu_ptr(pool, cpu) = p; 2909 2910 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 2911 if (!hash || IS_ERR(hash)) 2912 goto out_free; 2913 2914 p->md5_desc.tfm = hash; 2915 } 2916 return pool; 2917 out_free: 2918 __tcp_free_md5sig_pool(pool); 2919 return NULL; 2920 } 2921 2922 struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk) 2923 { 2924 struct tcp_md5sig_pool * __percpu *pool; 2925 int alloc = 0; 2926 2927 retry: 2928 spin_lock_bh(&tcp_md5sig_pool_lock); 2929 pool = tcp_md5sig_pool; 2930 if (tcp_md5sig_users++ == 0) { 2931 alloc = 1; 2932 spin_unlock_bh(&tcp_md5sig_pool_lock); 2933 } else if (!pool) { 2934 tcp_md5sig_users--; 2935 spin_unlock_bh(&tcp_md5sig_pool_lock); 2936 cpu_relax(); 2937 goto retry; 2938 } else 2939 spin_unlock_bh(&tcp_md5sig_pool_lock); 2940 2941 if (alloc) { 2942 /* we cannot hold spinlock here because this may sleep. */ 2943 struct tcp_md5sig_pool * __percpu *p; 2944 2945 p = __tcp_alloc_md5sig_pool(sk); 2946 spin_lock_bh(&tcp_md5sig_pool_lock); 2947 if (!p) { 2948 tcp_md5sig_users--; 2949 spin_unlock_bh(&tcp_md5sig_pool_lock); 2950 return NULL; 2951 } 2952 pool = tcp_md5sig_pool; 2953 if (pool) { 2954 /* oops, it has already been assigned. */ 2955 spin_unlock_bh(&tcp_md5sig_pool_lock); 2956 __tcp_free_md5sig_pool(p); 2957 } else { 2958 tcp_md5sig_pool = pool = p; 2959 spin_unlock_bh(&tcp_md5sig_pool_lock); 2960 } 2961 } 2962 return pool; 2963 } 2964 EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 2965 2966 2967 /** 2968 * tcp_get_md5sig_pool - get md5sig_pool for this user 2969 * 2970 * We use percpu structure, so if we succeed, we exit with preemption 2971 * and BH disabled, to make sure another thread or softirq handling 2972 * wont try to get same context. 2973 */ 2974 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) 2975 { 2976 struct tcp_md5sig_pool * __percpu *p; 2977 2978 local_bh_disable(); 2979 2980 spin_lock(&tcp_md5sig_pool_lock); 2981 p = tcp_md5sig_pool; 2982 if (p) 2983 tcp_md5sig_users++; 2984 spin_unlock(&tcp_md5sig_pool_lock); 2985 2986 if (p) 2987 return *this_cpu_ptr(p); 2988 2989 local_bh_enable(); 2990 return NULL; 2991 } 2992 EXPORT_SYMBOL(tcp_get_md5sig_pool); 2993 2994 void tcp_put_md5sig_pool(void) 2995 { 2996 local_bh_enable(); 2997 tcp_free_md5sig_pool(); 2998 } 2999 EXPORT_SYMBOL(tcp_put_md5sig_pool); 3000 3001 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp, 3002 struct tcphdr *th) 3003 { 3004 struct scatterlist sg; 3005 int err; 3006 3007 __sum16 old_checksum = th->check; 3008 th->check = 0; 3009 /* options aren't included in the hash */ 3010 sg_init_one(&sg, th, sizeof(struct tcphdr)); 3011 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr)); 3012 th->check = old_checksum; 3013 return err; 3014 } 3015 EXPORT_SYMBOL(tcp_md5_hash_header); 3016 3017 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, 3018 struct sk_buff *skb, unsigned header_len) 3019 { 3020 struct scatterlist sg; 3021 const struct tcphdr *tp = tcp_hdr(skb); 3022 struct hash_desc *desc = &hp->md5_desc; 3023 unsigned i; 3024 const unsigned head_data_len = skb_headlen(skb) > header_len ? 3025 skb_headlen(skb) - header_len : 0; 3026 const struct skb_shared_info *shi = skb_shinfo(skb); 3027 struct sk_buff *frag_iter; 3028 3029 sg_init_table(&sg, 1); 3030 3031 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len); 3032 if (crypto_hash_update(desc, &sg, head_data_len)) 3033 return 1; 3034 3035 for (i = 0; i < shi->nr_frags; ++i) { 3036 const struct skb_frag_struct *f = &shi->frags[i]; 3037 sg_set_page(&sg, f->page, f->size, f->page_offset); 3038 if (crypto_hash_update(desc, &sg, f->size)) 3039 return 1; 3040 } 3041 3042 skb_walk_frags(skb, frag_iter) 3043 if (tcp_md5_hash_skb_data(hp, frag_iter, 0)) 3044 return 1; 3045 3046 return 0; 3047 } 3048 EXPORT_SYMBOL(tcp_md5_hash_skb_data); 3049 3050 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key) 3051 { 3052 struct scatterlist sg; 3053 3054 sg_init_one(&sg, key->key, key->keylen); 3055 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen); 3056 } 3057 EXPORT_SYMBOL(tcp_md5_hash_key); 3058 3059 #endif 3060 3061 /** 3062 * Each Responder maintains up to two secret values concurrently for 3063 * efficient secret rollover. Each secret value has 4 states: 3064 * 3065 * Generating. (tcp_secret_generating != tcp_secret_primary) 3066 * Generates new Responder-Cookies, but not yet used for primary 3067 * verification. This is a short-term state, typically lasting only 3068 * one round trip time (RTT). 3069 * 3070 * Primary. (tcp_secret_generating == tcp_secret_primary) 3071 * Used both for generation and primary verification. 3072 * 3073 * Retiring. (tcp_secret_retiring != tcp_secret_secondary) 3074 * Used for verification, until the first failure that can be 3075 * verified by the newer Generating secret. At that time, this 3076 * cookie's state is changed to Secondary, and the Generating 3077 * cookie's state is changed to Primary. This is a short-term state, 3078 * typically lasting only one round trip time (RTT). 3079 * 3080 * Secondary. (tcp_secret_retiring == tcp_secret_secondary) 3081 * Used for secondary verification, after primary verification 3082 * failures. This state lasts no more than twice the Maximum Segment 3083 * Lifetime (2MSL). Then, the secret is discarded. 3084 */ 3085 struct tcp_cookie_secret { 3086 /* The secret is divided into two parts. The digest part is the 3087 * equivalent of previously hashing a secret and saving the state, 3088 * and serves as an initialization vector (IV). The message part 3089 * serves as the trailing secret. 3090 */ 3091 u32 secrets[COOKIE_WORKSPACE_WORDS]; 3092 unsigned long expires; 3093 }; 3094 3095 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL) 3096 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2) 3097 #define TCP_SECRET_LIFE (HZ * 600) 3098 3099 static struct tcp_cookie_secret tcp_secret_one; 3100 static struct tcp_cookie_secret tcp_secret_two; 3101 3102 /* Essentially a circular list, without dynamic allocation. */ 3103 static struct tcp_cookie_secret *tcp_secret_generating; 3104 static struct tcp_cookie_secret *tcp_secret_primary; 3105 static struct tcp_cookie_secret *tcp_secret_retiring; 3106 static struct tcp_cookie_secret *tcp_secret_secondary; 3107 3108 static DEFINE_SPINLOCK(tcp_secret_locker); 3109 3110 /* Select a pseudo-random word in the cookie workspace. 3111 */ 3112 static inline u32 tcp_cookie_work(const u32 *ws, const int n) 3113 { 3114 return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])]; 3115 } 3116 3117 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed. 3118 * Called in softirq context. 3119 * Returns: 0 for success. 3120 */ 3121 int tcp_cookie_generator(u32 *bakery) 3122 { 3123 unsigned long jiffy = jiffies; 3124 3125 if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) { 3126 spin_lock_bh(&tcp_secret_locker); 3127 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) { 3128 /* refreshed by another */ 3129 memcpy(bakery, 3130 &tcp_secret_generating->secrets[0], 3131 COOKIE_WORKSPACE_WORDS); 3132 } else { 3133 /* still needs refreshing */ 3134 get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS); 3135 3136 /* The first time, paranoia assumes that the 3137 * randomization function isn't as strong. But, 3138 * this secret initialization is delayed until 3139 * the last possible moment (packet arrival). 3140 * Although that time is observable, it is 3141 * unpredictably variable. Mash in the most 3142 * volatile clock bits available, and expire the 3143 * secret extra quickly. 3144 */ 3145 if (unlikely(tcp_secret_primary->expires == 3146 tcp_secret_secondary->expires)) { 3147 struct timespec tv; 3148 3149 getnstimeofday(&tv); 3150 bakery[COOKIE_DIGEST_WORDS+0] ^= 3151 (u32)tv.tv_nsec; 3152 3153 tcp_secret_secondary->expires = jiffy 3154 + TCP_SECRET_1MSL 3155 + (0x0f & tcp_cookie_work(bakery, 0)); 3156 } else { 3157 tcp_secret_secondary->expires = jiffy 3158 + TCP_SECRET_LIFE 3159 + (0xff & tcp_cookie_work(bakery, 1)); 3160 tcp_secret_primary->expires = jiffy 3161 + TCP_SECRET_2MSL 3162 + (0x1f & tcp_cookie_work(bakery, 2)); 3163 } 3164 memcpy(&tcp_secret_secondary->secrets[0], 3165 bakery, COOKIE_WORKSPACE_WORDS); 3166 3167 rcu_assign_pointer(tcp_secret_generating, 3168 tcp_secret_secondary); 3169 rcu_assign_pointer(tcp_secret_retiring, 3170 tcp_secret_primary); 3171 /* 3172 * Neither call_rcu() nor synchronize_rcu() needed. 3173 * Retiring data is not freed. It is replaced after 3174 * further (locked) pointer updates, and a quiet time 3175 * (minimum 1MSL, maximum LIFE - 2MSL). 3176 */ 3177 } 3178 spin_unlock_bh(&tcp_secret_locker); 3179 } else { 3180 rcu_read_lock_bh(); 3181 memcpy(bakery, 3182 &rcu_dereference(tcp_secret_generating)->secrets[0], 3183 COOKIE_WORKSPACE_WORDS); 3184 rcu_read_unlock_bh(); 3185 } 3186 return 0; 3187 } 3188 EXPORT_SYMBOL(tcp_cookie_generator); 3189 3190 void tcp_done(struct sock *sk) 3191 { 3192 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 3193 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS); 3194 3195 tcp_set_state(sk, TCP_CLOSE); 3196 tcp_clear_xmit_timers(sk); 3197 3198 sk->sk_shutdown = SHUTDOWN_MASK; 3199 3200 if (!sock_flag(sk, SOCK_DEAD)) 3201 sk->sk_state_change(sk); 3202 else 3203 inet_csk_destroy_sock(sk); 3204 } 3205 EXPORT_SYMBOL_GPL(tcp_done); 3206 3207 extern struct tcp_congestion_ops tcp_reno; 3208 3209 static __initdata unsigned long thash_entries; 3210 static int __init set_thash_entries(char *str) 3211 { 3212 if (!str) 3213 return 0; 3214 thash_entries = simple_strtoul(str, &str, 0); 3215 return 1; 3216 } 3217 __setup("thash_entries=", set_thash_entries); 3218 3219 void __init tcp_init(void) 3220 { 3221 struct sk_buff *skb = NULL; 3222 unsigned long nr_pages, limit; 3223 int i, max_share, cnt; 3224 unsigned long jiffy = jiffies; 3225 3226 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb)); 3227 3228 percpu_counter_init(&tcp_sockets_allocated, 0); 3229 percpu_counter_init(&tcp_orphan_count, 0); 3230 tcp_hashinfo.bind_bucket_cachep = 3231 kmem_cache_create("tcp_bind_bucket", 3232 sizeof(struct inet_bind_bucket), 0, 3233 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3234 3235 /* Size and allocate the main established and bind bucket 3236 * hash tables. 3237 * 3238 * The methodology is similar to that of the buffer cache. 3239 */ 3240 tcp_hashinfo.ehash = 3241 alloc_large_system_hash("TCP established", 3242 sizeof(struct inet_ehash_bucket), 3243 thash_entries, 3244 (totalram_pages >= 128 * 1024) ? 3245 13 : 15, 3246 0, 3247 NULL, 3248 &tcp_hashinfo.ehash_mask, 3249 thash_entries ? 0 : 512 * 1024); 3250 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) { 3251 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i); 3252 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i); 3253 } 3254 if (inet_ehash_locks_alloc(&tcp_hashinfo)) 3255 panic("TCP: failed to alloc ehash_locks"); 3256 tcp_hashinfo.bhash = 3257 alloc_large_system_hash("TCP bind", 3258 sizeof(struct inet_bind_hashbucket), 3259 tcp_hashinfo.ehash_mask + 1, 3260 (totalram_pages >= 128 * 1024) ? 3261 13 : 15, 3262 0, 3263 &tcp_hashinfo.bhash_size, 3264 NULL, 3265 64 * 1024); 3266 tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size; 3267 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 3268 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 3269 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 3270 } 3271 3272 3273 cnt = tcp_hashinfo.ehash_mask + 1; 3274 3275 tcp_death_row.sysctl_max_tw_buckets = cnt / 2; 3276 sysctl_tcp_max_orphans = cnt / 2; 3277 sysctl_max_syn_backlog = max(128, cnt / 256); 3278 3279 /* Set the pressure threshold to be a fraction of global memory that 3280 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of 3281 * memory, with a floor of 128 pages. 3282 */ 3283 nr_pages = totalram_pages - totalhigh_pages; 3284 limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); 3285 limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); 3286 limit = max(limit, 128UL); 3287 sysctl_tcp_mem[0] = limit / 4 * 3; 3288 sysctl_tcp_mem[1] = limit; 3289 sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; 3290 3291 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 3292 limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7); 3293 max_share = min(4UL*1024*1024, limit); 3294 3295 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM; 3296 sysctl_tcp_wmem[1] = 16*1024; 3297 sysctl_tcp_wmem[2] = max(64*1024, max_share); 3298 3299 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; 3300 sysctl_tcp_rmem[1] = 87380; 3301 sysctl_tcp_rmem[2] = max(87380, max_share); 3302 3303 printk(KERN_INFO "TCP: Hash tables configured " 3304 "(established %u bind %u)\n", 3305 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size); 3306 3307 tcp_register_congestion_control(&tcp_reno); 3308 3309 memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets)); 3310 memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets)); 3311 tcp_secret_one.expires = jiffy; /* past due */ 3312 tcp_secret_two.expires = jiffy; /* past due */ 3313 tcp_secret_generating = &tcp_secret_one; 3314 tcp_secret_primary = &tcp_secret_one; 3315 tcp_secret_retiring = &tcp_secret_two; 3316 tcp_secret_secondary = &tcp_secret_two; 3317 } 3318