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 #define pr_fmt(fmt) "TCP: " fmt 249 250 #include <linux/kernel.h> 251 #include <linux/module.h> 252 #include <linux/types.h> 253 #include <linux/fcntl.h> 254 #include <linux/poll.h> 255 #include <linux/init.h> 256 #include <linux/fs.h> 257 #include <linux/skbuff.h> 258 #include <linux/scatterlist.h> 259 #include <linux/splice.h> 260 #include <linux/net.h> 261 #include <linux/socket.h> 262 #include <linux/random.h> 263 #include <linux/bootmem.h> 264 #include <linux/highmem.h> 265 #include <linux/swap.h> 266 #include <linux/cache.h> 267 #include <linux/err.h> 268 #include <linux/crypto.h> 269 #include <linux/time.h> 270 #include <linux/slab.h> 271 272 #include <net/icmp.h> 273 #include <net/tcp.h> 274 #include <net/xfrm.h> 275 #include <net/ip.h> 276 #include <net/netdma.h> 277 #include <net/sock.h> 278 279 #include <asm/uaccess.h> 280 #include <asm/ioctls.h> 281 282 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 283 284 struct percpu_counter tcp_orphan_count; 285 EXPORT_SYMBOL_GPL(tcp_orphan_count); 286 287 int sysctl_tcp_wmem[3] __read_mostly; 288 int sysctl_tcp_rmem[3] __read_mostly; 289 290 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 /* Address-family independent initialization for a tcp_sock. 367 * 368 * NOTE: A lot of things set to zero explicitly by call to 369 * sk_alloc() so need not be done here. 370 */ 371 void tcp_init_sock(struct sock *sk) 372 { 373 struct inet_connection_sock *icsk = inet_csk(sk); 374 struct tcp_sock *tp = tcp_sk(sk); 375 376 skb_queue_head_init(&tp->out_of_order_queue); 377 tcp_init_xmit_timers(sk); 378 tcp_prequeue_init(tp); 379 380 icsk->icsk_rto = TCP_TIMEOUT_INIT; 381 tp->mdev = TCP_TIMEOUT_INIT; 382 383 /* So many TCP implementations out there (incorrectly) count the 384 * initial SYN frame in their delayed-ACK and congestion control 385 * algorithms that we must have the following bandaid to talk 386 * efficiently to them. -DaveM 387 */ 388 tp->snd_cwnd = TCP_INIT_CWND; 389 390 /* See draft-stevens-tcpca-spec-01 for discussion of the 391 * initialization of these values. 392 */ 393 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 394 tp->snd_cwnd_clamp = ~0; 395 tp->mss_cache = TCP_MSS_DEFAULT; 396 397 tp->reordering = sysctl_tcp_reordering; 398 tcp_enable_early_retrans(tp); 399 icsk->icsk_ca_ops = &tcp_init_congestion_ops; 400 401 sk->sk_state = TCP_CLOSE; 402 403 sk->sk_write_space = sk_stream_write_space; 404 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 405 406 icsk->icsk_sync_mss = tcp_sync_mss; 407 408 /* TCP Cookie Transactions */ 409 if (sysctl_tcp_cookie_size > 0) { 410 /* Default, cookies without s_data_payload. */ 411 tp->cookie_values = 412 kzalloc(sizeof(*tp->cookie_values), 413 sk->sk_allocation); 414 if (tp->cookie_values != NULL) 415 kref_init(&tp->cookie_values->kref); 416 } 417 /* Presumed zeroed, in order of appearance: 418 * cookie_in_always, cookie_out_never, 419 * s_data_constant, s_data_in, s_data_out 420 */ 421 sk->sk_sndbuf = sysctl_tcp_wmem[1]; 422 sk->sk_rcvbuf = sysctl_tcp_rmem[1]; 423 424 local_bh_disable(); 425 sock_update_memcg(sk); 426 sk_sockets_allocated_inc(sk); 427 local_bh_enable(); 428 } 429 EXPORT_SYMBOL(tcp_init_sock); 430 431 /* 432 * Wait for a TCP event. 433 * 434 * Note that we don't need to lock the socket, as the upper poll layers 435 * take care of normal races (between the test and the event) and we don't 436 * go look at any of the socket buffers directly. 437 */ 438 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 439 { 440 unsigned int mask; 441 struct sock *sk = sock->sk; 442 const struct tcp_sock *tp = tcp_sk(sk); 443 444 sock_poll_wait(file, sk_sleep(sk), wait); 445 if (sk->sk_state == TCP_LISTEN) 446 return inet_csk_listen_poll(sk); 447 448 /* Socket is not locked. We are protected from async events 449 * by poll logic and correct handling of state changes 450 * made by other threads is impossible in any case. 451 */ 452 453 mask = 0; 454 455 /* 456 * POLLHUP is certainly not done right. But poll() doesn't 457 * have a notion of HUP in just one direction, and for a 458 * socket the read side is more interesting. 459 * 460 * Some poll() documentation says that POLLHUP is incompatible 461 * with the POLLOUT/POLLWR flags, so somebody should check this 462 * all. But careful, it tends to be safer to return too many 463 * bits than too few, and you can easily break real applications 464 * if you don't tell them that something has hung up! 465 * 466 * Check-me. 467 * 468 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 469 * our fs/select.c). It means that after we received EOF, 470 * poll always returns immediately, making impossible poll() on write() 471 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 472 * if and only if shutdown has been made in both directions. 473 * Actually, it is interesting to look how Solaris and DUX 474 * solve this dilemma. I would prefer, if POLLHUP were maskable, 475 * then we could set it on SND_SHUTDOWN. BTW examples given 476 * in Stevens' books assume exactly this behaviour, it explains 477 * why POLLHUP is incompatible with POLLOUT. --ANK 478 * 479 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 480 * blocking on fresh not-connected or disconnected socket. --ANK 481 */ 482 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 483 mask |= POLLHUP; 484 if (sk->sk_shutdown & RCV_SHUTDOWN) 485 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 486 487 /* Connected? */ 488 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) { 489 int target = sock_rcvlowat(sk, 0, INT_MAX); 490 491 if (tp->urg_seq == tp->copied_seq && 492 !sock_flag(sk, SOCK_URGINLINE) && 493 tp->urg_data) 494 target++; 495 496 /* Potential race condition. If read of tp below will 497 * escape above sk->sk_state, we can be illegally awaken 498 * in SYN_* states. */ 499 if (tp->rcv_nxt - tp->copied_seq >= target) 500 mask |= POLLIN | POLLRDNORM; 501 502 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 503 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) { 504 mask |= POLLOUT | POLLWRNORM; 505 } else { /* send SIGIO later */ 506 set_bit(SOCK_ASYNC_NOSPACE, 507 &sk->sk_socket->flags); 508 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 509 510 /* Race breaker. If space is freed after 511 * wspace test but before the flags are set, 512 * IO signal will be lost. 513 */ 514 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) 515 mask |= POLLOUT | POLLWRNORM; 516 } 517 } else 518 mask |= POLLOUT | POLLWRNORM; 519 520 if (tp->urg_data & TCP_URG_VALID) 521 mask |= POLLPRI; 522 } 523 /* This barrier is coupled with smp_wmb() in tcp_reset() */ 524 smp_rmb(); 525 if (sk->sk_err) 526 mask |= POLLERR; 527 528 return mask; 529 } 530 EXPORT_SYMBOL(tcp_poll); 531 532 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 533 { 534 struct tcp_sock *tp = tcp_sk(sk); 535 int answ; 536 537 switch (cmd) { 538 case SIOCINQ: 539 if (sk->sk_state == TCP_LISTEN) 540 return -EINVAL; 541 542 lock_sock(sk); 543 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 544 answ = 0; 545 else if (sock_flag(sk, SOCK_URGINLINE) || 546 !tp->urg_data || 547 before(tp->urg_seq, tp->copied_seq) || 548 !before(tp->urg_seq, tp->rcv_nxt)) { 549 struct sk_buff *skb; 550 551 answ = tp->rcv_nxt - tp->copied_seq; 552 553 /* Subtract 1, if FIN is in queue. */ 554 skb = skb_peek_tail(&sk->sk_receive_queue); 555 if (answ && skb) 556 answ -= tcp_hdr(skb)->fin; 557 } else 558 answ = tp->urg_seq - tp->copied_seq; 559 release_sock(sk); 560 break; 561 case SIOCATMARK: 562 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 563 break; 564 case SIOCOUTQ: 565 if (sk->sk_state == TCP_LISTEN) 566 return -EINVAL; 567 568 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 569 answ = 0; 570 else 571 answ = tp->write_seq - tp->snd_una; 572 break; 573 case SIOCOUTQNSD: 574 if (sk->sk_state == TCP_LISTEN) 575 return -EINVAL; 576 577 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 578 answ = 0; 579 else 580 answ = tp->write_seq - tp->snd_nxt; 581 break; 582 default: 583 return -ENOIOCTLCMD; 584 } 585 586 return put_user(answ, (int __user *)arg); 587 } 588 EXPORT_SYMBOL(tcp_ioctl); 589 590 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 591 { 592 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH; 593 tp->pushed_seq = tp->write_seq; 594 } 595 596 static inline bool forced_push(const struct tcp_sock *tp) 597 { 598 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 599 } 600 601 static inline void skb_entail(struct sock *sk, struct sk_buff *skb) 602 { 603 struct tcp_sock *tp = tcp_sk(sk); 604 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 605 606 skb->csum = 0; 607 tcb->seq = tcb->end_seq = tp->write_seq; 608 tcb->tcp_flags = TCPHDR_ACK; 609 tcb->sacked = 0; 610 skb_header_release(skb); 611 tcp_add_write_queue_tail(sk, skb); 612 sk->sk_wmem_queued += skb->truesize; 613 sk_mem_charge(sk, skb->truesize); 614 if (tp->nonagle & TCP_NAGLE_PUSH) 615 tp->nonagle &= ~TCP_NAGLE_PUSH; 616 } 617 618 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags) 619 { 620 if (flags & MSG_OOB) 621 tp->snd_up = tp->write_seq; 622 } 623 624 static inline void tcp_push(struct sock *sk, int flags, int mss_now, 625 int nonagle) 626 { 627 if (tcp_send_head(sk)) { 628 struct tcp_sock *tp = tcp_sk(sk); 629 630 if (!(flags & MSG_MORE) || forced_push(tp)) 631 tcp_mark_push(tp, tcp_write_queue_tail(sk)); 632 633 tcp_mark_urg(tp, flags); 634 __tcp_push_pending_frames(sk, mss_now, 635 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle); 636 } 637 } 638 639 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, 640 unsigned int offset, size_t len) 641 { 642 struct tcp_splice_state *tss = rd_desc->arg.data; 643 int ret; 644 645 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len), 646 tss->flags); 647 if (ret > 0) 648 rd_desc->count -= ret; 649 return ret; 650 } 651 652 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss) 653 { 654 /* Store TCP splice context information in read_descriptor_t. */ 655 read_descriptor_t rd_desc = { 656 .arg.data = tss, 657 .count = tss->len, 658 }; 659 660 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv); 661 } 662 663 /** 664 * tcp_splice_read - splice data from TCP socket to a pipe 665 * @sock: socket to splice from 666 * @ppos: position (not valid) 667 * @pipe: pipe to splice to 668 * @len: number of bytes to splice 669 * @flags: splice modifier flags 670 * 671 * Description: 672 * Will read pages from given socket and fill them into a pipe. 673 * 674 **/ 675 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, 676 struct pipe_inode_info *pipe, size_t len, 677 unsigned int flags) 678 { 679 struct sock *sk = sock->sk; 680 struct tcp_splice_state tss = { 681 .pipe = pipe, 682 .len = len, 683 .flags = flags, 684 }; 685 long timeo; 686 ssize_t spliced; 687 int ret; 688 689 sock_rps_record_flow(sk); 690 /* 691 * We can't seek on a socket input 692 */ 693 if (unlikely(*ppos)) 694 return -ESPIPE; 695 696 ret = spliced = 0; 697 698 lock_sock(sk); 699 700 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK); 701 while (tss.len) { 702 ret = __tcp_splice_read(sk, &tss); 703 if (ret < 0) 704 break; 705 else if (!ret) { 706 if (spliced) 707 break; 708 if (sock_flag(sk, SOCK_DONE)) 709 break; 710 if (sk->sk_err) { 711 ret = sock_error(sk); 712 break; 713 } 714 if (sk->sk_shutdown & RCV_SHUTDOWN) 715 break; 716 if (sk->sk_state == TCP_CLOSE) { 717 /* 718 * This occurs when user tries to read 719 * from never connected socket. 720 */ 721 if (!sock_flag(sk, SOCK_DONE)) 722 ret = -ENOTCONN; 723 break; 724 } 725 if (!timeo) { 726 ret = -EAGAIN; 727 break; 728 } 729 sk_wait_data(sk, &timeo); 730 if (signal_pending(current)) { 731 ret = sock_intr_errno(timeo); 732 break; 733 } 734 continue; 735 } 736 tss.len -= ret; 737 spliced += ret; 738 739 if (!timeo) 740 break; 741 release_sock(sk); 742 lock_sock(sk); 743 744 if (sk->sk_err || sk->sk_state == TCP_CLOSE || 745 (sk->sk_shutdown & RCV_SHUTDOWN) || 746 signal_pending(current)) 747 break; 748 } 749 750 release_sock(sk); 751 752 if (spliced) 753 return spliced; 754 755 return ret; 756 } 757 EXPORT_SYMBOL(tcp_splice_read); 758 759 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp) 760 { 761 struct sk_buff *skb; 762 763 /* The TCP header must be at least 32-bit aligned. */ 764 size = ALIGN(size, 4); 765 766 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); 767 if (skb) { 768 if (sk_wmem_schedule(sk, skb->truesize)) { 769 skb_reserve(skb, sk->sk_prot->max_header); 770 /* 771 * Make sure that we have exactly size bytes 772 * available to the caller, no more, no less. 773 */ 774 skb->avail_size = size; 775 return skb; 776 } 777 __kfree_skb(skb); 778 } else { 779 sk->sk_prot->enter_memory_pressure(sk); 780 sk_stream_moderate_sndbuf(sk); 781 } 782 return NULL; 783 } 784 785 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now, 786 int large_allowed) 787 { 788 struct tcp_sock *tp = tcp_sk(sk); 789 u32 xmit_size_goal, old_size_goal; 790 791 xmit_size_goal = mss_now; 792 793 if (large_allowed && sk_can_gso(sk)) { 794 xmit_size_goal = ((sk->sk_gso_max_size - 1) - 795 inet_csk(sk)->icsk_af_ops->net_header_len - 796 inet_csk(sk)->icsk_ext_hdr_len - 797 tp->tcp_header_len); 798 799 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal); 800 801 /* We try hard to avoid divides here */ 802 old_size_goal = tp->xmit_size_goal_segs * mss_now; 803 804 if (likely(old_size_goal <= xmit_size_goal && 805 old_size_goal + mss_now > xmit_size_goal)) { 806 xmit_size_goal = old_size_goal; 807 } else { 808 tp->xmit_size_goal_segs = xmit_size_goal / mss_now; 809 xmit_size_goal = tp->xmit_size_goal_segs * mss_now; 810 } 811 } 812 813 return max(xmit_size_goal, mss_now); 814 } 815 816 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags) 817 { 818 int mss_now; 819 820 mss_now = tcp_current_mss(sk); 821 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB)); 822 823 return mss_now; 824 } 825 826 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset, 827 size_t psize, int flags) 828 { 829 struct tcp_sock *tp = tcp_sk(sk); 830 int mss_now, size_goal; 831 int err; 832 ssize_t copied; 833 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 834 835 /* Wait for a connection to finish. */ 836 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 837 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 838 goto out_err; 839 840 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 841 842 mss_now = tcp_send_mss(sk, &size_goal, flags); 843 copied = 0; 844 845 err = -EPIPE; 846 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 847 goto out_err; 848 849 while (psize > 0) { 850 struct sk_buff *skb = tcp_write_queue_tail(sk); 851 struct page *page = pages[poffset / PAGE_SIZE]; 852 int copy, i; 853 int offset = poffset % PAGE_SIZE; 854 int size = min_t(size_t, psize, PAGE_SIZE - offset); 855 bool can_coalesce; 856 857 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { 858 new_segment: 859 if (!sk_stream_memory_free(sk)) 860 goto wait_for_sndbuf; 861 862 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation); 863 if (!skb) 864 goto wait_for_memory; 865 866 skb_entail(sk, skb); 867 copy = size_goal; 868 } 869 870 if (copy > size) 871 copy = size; 872 873 i = skb_shinfo(skb)->nr_frags; 874 can_coalesce = skb_can_coalesce(skb, i, page, offset); 875 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 876 tcp_mark_push(tp, skb); 877 goto new_segment; 878 } 879 if (!sk_wmem_schedule(sk, copy)) 880 goto wait_for_memory; 881 882 if (can_coalesce) { 883 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 884 } else { 885 get_page(page); 886 skb_fill_page_desc(skb, i, page, offset, copy); 887 } 888 889 skb->len += copy; 890 skb->data_len += copy; 891 skb->truesize += copy; 892 sk->sk_wmem_queued += copy; 893 sk_mem_charge(sk, copy); 894 skb->ip_summed = CHECKSUM_PARTIAL; 895 tp->write_seq += copy; 896 TCP_SKB_CB(skb)->end_seq += copy; 897 skb_shinfo(skb)->gso_segs = 0; 898 899 if (!copied) 900 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 901 902 copied += copy; 903 poffset += copy; 904 if (!(psize -= copy)) 905 goto out; 906 907 if (skb->len < size_goal || (flags & MSG_OOB)) 908 continue; 909 910 if (forced_push(tp)) { 911 tcp_mark_push(tp, skb); 912 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 913 } else if (skb == tcp_send_head(sk)) 914 tcp_push_one(sk, mss_now); 915 continue; 916 917 wait_for_sndbuf: 918 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 919 wait_for_memory: 920 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 921 922 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 923 goto do_error; 924 925 mss_now = tcp_send_mss(sk, &size_goal, flags); 926 } 927 928 out: 929 if (copied && !(flags & MSG_SENDPAGE_NOTLAST)) 930 tcp_push(sk, flags, mss_now, tp->nonagle); 931 return copied; 932 933 do_error: 934 if (copied) 935 goto out; 936 out_err: 937 return sk_stream_error(sk, flags, err); 938 } 939 940 int tcp_sendpage(struct sock *sk, struct page *page, int offset, 941 size_t size, int flags) 942 { 943 ssize_t res; 944 945 if (!(sk->sk_route_caps & NETIF_F_SG) || 946 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 947 return sock_no_sendpage(sk->sk_socket, page, offset, size, 948 flags); 949 950 lock_sock(sk); 951 res = do_tcp_sendpages(sk, &page, offset, size, flags); 952 release_sock(sk); 953 return res; 954 } 955 EXPORT_SYMBOL(tcp_sendpage); 956 957 static inline int select_size(const struct sock *sk, bool sg) 958 { 959 const struct tcp_sock *tp = tcp_sk(sk); 960 int tmp = tp->mss_cache; 961 962 if (sg) { 963 if (sk_can_gso(sk)) { 964 /* Small frames wont use a full page: 965 * Payload will immediately follow tcp header. 966 */ 967 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER); 968 } else { 969 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 970 971 if (tmp >= pgbreak && 972 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 973 tmp = pgbreak; 974 } 975 } 976 977 return tmp; 978 } 979 980 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 981 size_t size) 982 { 983 struct iovec *iov; 984 struct tcp_sock *tp = tcp_sk(sk); 985 struct sk_buff *skb; 986 int iovlen, flags, err, copied; 987 int mss_now = 0, size_goal; 988 bool sg; 989 long timeo; 990 991 lock_sock(sk); 992 993 flags = msg->msg_flags; 994 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 995 996 /* Wait for a connection to finish. */ 997 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) 998 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 999 goto out_err; 1000 1001 if (unlikely(tp->repair)) { 1002 if (tp->repair_queue == TCP_RECV_QUEUE) { 1003 copied = tcp_send_rcvq(sk, msg, size); 1004 goto out; 1005 } 1006 1007 err = -EINVAL; 1008 if (tp->repair_queue == TCP_NO_QUEUE) 1009 goto out_err; 1010 1011 /* 'common' sending to sendq */ 1012 } 1013 1014 /* This should be in poll */ 1015 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 1016 1017 mss_now = tcp_send_mss(sk, &size_goal, flags); 1018 1019 /* Ok commence sending. */ 1020 iovlen = msg->msg_iovlen; 1021 iov = msg->msg_iov; 1022 copied = 0; 1023 1024 err = -EPIPE; 1025 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 1026 goto out_err; 1027 1028 sg = !!(sk->sk_route_caps & NETIF_F_SG); 1029 1030 while (--iovlen >= 0) { 1031 size_t seglen = iov->iov_len; 1032 unsigned char __user *from = iov->iov_base; 1033 1034 iov++; 1035 1036 while (seglen > 0) { 1037 int copy = 0; 1038 int max = size_goal; 1039 1040 skb = tcp_write_queue_tail(sk); 1041 if (tcp_send_head(sk)) { 1042 if (skb->ip_summed == CHECKSUM_NONE) 1043 max = mss_now; 1044 copy = max - skb->len; 1045 } 1046 1047 if (copy <= 0) { 1048 new_segment: 1049 /* Allocate new segment. If the interface is SG, 1050 * allocate skb fitting to single page. 1051 */ 1052 if (!sk_stream_memory_free(sk)) 1053 goto wait_for_sndbuf; 1054 1055 skb = sk_stream_alloc_skb(sk, 1056 select_size(sk, sg), 1057 sk->sk_allocation); 1058 if (!skb) 1059 goto wait_for_memory; 1060 1061 /* 1062 * Check whether we can use HW checksum. 1063 */ 1064 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 1065 skb->ip_summed = CHECKSUM_PARTIAL; 1066 1067 skb_entail(sk, skb); 1068 copy = size_goal; 1069 max = size_goal; 1070 } 1071 1072 /* Try to append data to the end of skb. */ 1073 if (copy > seglen) 1074 copy = seglen; 1075 1076 /* Where to copy to? */ 1077 if (skb_availroom(skb) > 0) { 1078 /* We have some space in skb head. Superb! */ 1079 copy = min_t(int, copy, skb_availroom(skb)); 1080 err = skb_add_data_nocache(sk, skb, from, copy); 1081 if (err) 1082 goto do_fault; 1083 } else { 1084 bool merge = false; 1085 int i = skb_shinfo(skb)->nr_frags; 1086 struct page *page = sk->sk_sndmsg_page; 1087 int off; 1088 1089 if (page && page_count(page) == 1) 1090 sk->sk_sndmsg_off = 0; 1091 1092 off = sk->sk_sndmsg_off; 1093 1094 if (skb_can_coalesce(skb, i, page, off) && 1095 off != PAGE_SIZE) { 1096 /* We can extend the last page 1097 * fragment. */ 1098 merge = true; 1099 } else if (i == MAX_SKB_FRAGS || !sg) { 1100 /* Need to add new fragment and cannot 1101 * do this because interface is non-SG, 1102 * or because all the page slots are 1103 * busy. */ 1104 tcp_mark_push(tp, skb); 1105 goto new_segment; 1106 } else if (page) { 1107 if (off == PAGE_SIZE) { 1108 put_page(page); 1109 sk->sk_sndmsg_page = page = NULL; 1110 off = 0; 1111 } 1112 } else 1113 off = 0; 1114 1115 if (copy > PAGE_SIZE - off) 1116 copy = PAGE_SIZE - off; 1117 1118 if (!sk_wmem_schedule(sk, copy)) 1119 goto wait_for_memory; 1120 1121 if (!page) { 1122 /* Allocate new cache page. */ 1123 if (!(page = sk_stream_alloc_page(sk))) 1124 goto wait_for_memory; 1125 } 1126 1127 /* Time to copy data. We are close to 1128 * the end! */ 1129 err = skb_copy_to_page_nocache(sk, from, skb, 1130 page, off, copy); 1131 if (err) { 1132 /* If this page was new, give it to the 1133 * socket so it does not get leaked. 1134 */ 1135 if (!sk->sk_sndmsg_page) { 1136 sk->sk_sndmsg_page = page; 1137 sk->sk_sndmsg_off = 0; 1138 } 1139 goto do_error; 1140 } 1141 1142 /* Update the skb. */ 1143 if (merge) { 1144 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1145 } else { 1146 skb_fill_page_desc(skb, i, page, off, copy); 1147 if (sk->sk_sndmsg_page) { 1148 get_page(page); 1149 } else if (off + copy < PAGE_SIZE) { 1150 get_page(page); 1151 sk->sk_sndmsg_page = page; 1152 } 1153 } 1154 1155 sk->sk_sndmsg_off = off + copy; 1156 } 1157 1158 if (!copied) 1159 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 1160 1161 tp->write_seq += copy; 1162 TCP_SKB_CB(skb)->end_seq += copy; 1163 skb_shinfo(skb)->gso_segs = 0; 1164 1165 from += copy; 1166 copied += copy; 1167 if ((seglen -= copy) == 0 && iovlen == 0) 1168 goto out; 1169 1170 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair)) 1171 continue; 1172 1173 if (forced_push(tp)) { 1174 tcp_mark_push(tp, skb); 1175 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 1176 } else if (skb == tcp_send_head(sk)) 1177 tcp_push_one(sk, mss_now); 1178 continue; 1179 1180 wait_for_sndbuf: 1181 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1182 wait_for_memory: 1183 if (copied && likely(!tp->repair)) 1184 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 1185 1186 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 1187 goto do_error; 1188 1189 mss_now = tcp_send_mss(sk, &size_goal, flags); 1190 } 1191 } 1192 1193 out: 1194 if (copied && likely(!tp->repair)) 1195 tcp_push(sk, flags, mss_now, tp->nonagle); 1196 release_sock(sk); 1197 return copied; 1198 1199 do_fault: 1200 if (!skb->len) { 1201 tcp_unlink_write_queue(skb, sk); 1202 /* It is the one place in all of TCP, except connection 1203 * reset, where we can be unlinking the send_head. 1204 */ 1205 tcp_check_send_head(sk, skb); 1206 sk_wmem_free_skb(sk, skb); 1207 } 1208 1209 do_error: 1210 if (copied) 1211 goto out; 1212 out_err: 1213 err = sk_stream_error(sk, flags, err); 1214 release_sock(sk); 1215 return err; 1216 } 1217 EXPORT_SYMBOL(tcp_sendmsg); 1218 1219 /* 1220 * Handle reading urgent data. BSD has very simple semantics for 1221 * this, no blocking and very strange errors 8) 1222 */ 1223 1224 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags) 1225 { 1226 struct tcp_sock *tp = tcp_sk(sk); 1227 1228 /* No URG data to read. */ 1229 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || 1230 tp->urg_data == TCP_URG_READ) 1231 return -EINVAL; /* Yes this is right ! */ 1232 1233 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) 1234 return -ENOTCONN; 1235 1236 if (tp->urg_data & TCP_URG_VALID) { 1237 int err = 0; 1238 char c = tp->urg_data; 1239 1240 if (!(flags & MSG_PEEK)) 1241 tp->urg_data = TCP_URG_READ; 1242 1243 /* Read urgent data. */ 1244 msg->msg_flags |= MSG_OOB; 1245 1246 if (len > 0) { 1247 if (!(flags & MSG_TRUNC)) 1248 err = memcpy_toiovec(msg->msg_iov, &c, 1); 1249 len = 1; 1250 } else 1251 msg->msg_flags |= MSG_TRUNC; 1252 1253 return err ? -EFAULT : len; 1254 } 1255 1256 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 1257 return 0; 1258 1259 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and 1260 * the available implementations agree in this case: 1261 * this call should never block, independent of the 1262 * blocking state of the socket. 1263 * Mike <pall@rz.uni-karlsruhe.de> 1264 */ 1265 return -EAGAIN; 1266 } 1267 1268 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len) 1269 { 1270 struct sk_buff *skb; 1271 int copied = 0, err = 0; 1272 1273 /* XXX -- need to support SO_PEEK_OFF */ 1274 1275 skb_queue_walk(&sk->sk_write_queue, skb) { 1276 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len); 1277 if (err) 1278 break; 1279 1280 copied += skb->len; 1281 } 1282 1283 return err ?: copied; 1284 } 1285 1286 /* Clean up the receive buffer for full frames taken by the user, 1287 * then send an ACK if necessary. COPIED is the number of bytes 1288 * tcp_recvmsg has given to the user so far, it speeds up the 1289 * calculation of whether or not we must ACK for the sake of 1290 * a window update. 1291 */ 1292 void tcp_cleanup_rbuf(struct sock *sk, int copied) 1293 { 1294 struct tcp_sock *tp = tcp_sk(sk); 1295 bool time_to_ack = false; 1296 1297 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); 1298 1299 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq), 1300 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n", 1301 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt); 1302 1303 if (inet_csk_ack_scheduled(sk)) { 1304 const struct inet_connection_sock *icsk = inet_csk(sk); 1305 /* Delayed ACKs frequently hit locked sockets during bulk 1306 * receive. */ 1307 if (icsk->icsk_ack.blocked || 1308 /* Once-per-two-segments ACK was not sent by tcp_input.c */ 1309 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || 1310 /* 1311 * If this read emptied read buffer, we send ACK, if 1312 * connection is not bidirectional, user drained 1313 * receive buffer and there was a small segment 1314 * in queue. 1315 */ 1316 (copied > 0 && 1317 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || 1318 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && 1319 !icsk->icsk_ack.pingpong)) && 1320 !atomic_read(&sk->sk_rmem_alloc))) 1321 time_to_ack = true; 1322 } 1323 1324 /* We send an ACK if we can now advertise a non-zero window 1325 * which has been raised "significantly". 1326 * 1327 * Even if window raised up to infinity, do not send window open ACK 1328 * in states, where we will not receive more. It is useless. 1329 */ 1330 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 1331 __u32 rcv_window_now = tcp_receive_window(tp); 1332 1333 /* Optimize, __tcp_select_window() is not cheap. */ 1334 if (2*rcv_window_now <= tp->window_clamp) { 1335 __u32 new_window = __tcp_select_window(sk); 1336 1337 /* Send ACK now, if this read freed lots of space 1338 * in our buffer. Certainly, new_window is new window. 1339 * We can advertise it now, if it is not less than current one. 1340 * "Lots" means "at least twice" here. 1341 */ 1342 if (new_window && new_window >= 2 * rcv_window_now) 1343 time_to_ack = true; 1344 } 1345 } 1346 if (time_to_ack) 1347 tcp_send_ack(sk); 1348 } 1349 1350 static void tcp_prequeue_process(struct sock *sk) 1351 { 1352 struct sk_buff *skb; 1353 struct tcp_sock *tp = tcp_sk(sk); 1354 1355 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED); 1356 1357 /* RX process wants to run with disabled BHs, though it is not 1358 * necessary */ 1359 local_bh_disable(); 1360 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) 1361 sk_backlog_rcv(sk, skb); 1362 local_bh_enable(); 1363 1364 /* Clear memory counter. */ 1365 tp->ucopy.memory = 0; 1366 } 1367 1368 #ifdef CONFIG_NET_DMA 1369 static void tcp_service_net_dma(struct sock *sk, bool wait) 1370 { 1371 dma_cookie_t done, used; 1372 dma_cookie_t last_issued; 1373 struct tcp_sock *tp = tcp_sk(sk); 1374 1375 if (!tp->ucopy.dma_chan) 1376 return; 1377 1378 last_issued = tp->ucopy.dma_cookie; 1379 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1380 1381 do { 1382 if (dma_async_memcpy_complete(tp->ucopy.dma_chan, 1383 last_issued, &done, 1384 &used) == DMA_SUCCESS) { 1385 /* Safe to free early-copied skbs now */ 1386 __skb_queue_purge(&sk->sk_async_wait_queue); 1387 break; 1388 } else { 1389 struct sk_buff *skb; 1390 while ((skb = skb_peek(&sk->sk_async_wait_queue)) && 1391 (dma_async_is_complete(skb->dma_cookie, done, 1392 used) == DMA_SUCCESS)) { 1393 __skb_dequeue(&sk->sk_async_wait_queue); 1394 kfree_skb(skb); 1395 } 1396 } 1397 } while (wait); 1398 } 1399 #endif 1400 1401 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 1402 { 1403 struct sk_buff *skb; 1404 u32 offset; 1405 1406 skb_queue_walk(&sk->sk_receive_queue, skb) { 1407 offset = seq - TCP_SKB_CB(skb)->seq; 1408 if (tcp_hdr(skb)->syn) 1409 offset--; 1410 if (offset < skb->len || tcp_hdr(skb)->fin) { 1411 *off = offset; 1412 return skb; 1413 } 1414 } 1415 return NULL; 1416 } 1417 1418 /* 1419 * This routine provides an alternative to tcp_recvmsg() for routines 1420 * that would like to handle copying from skbuffs directly in 'sendfile' 1421 * fashion. 1422 * Note: 1423 * - It is assumed that the socket was locked by the caller. 1424 * - The routine does not block. 1425 * - At present, there is no support for reading OOB data 1426 * or for 'peeking' the socket using this routine 1427 * (although both would be easy to implement). 1428 */ 1429 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 1430 sk_read_actor_t recv_actor) 1431 { 1432 struct sk_buff *skb; 1433 struct tcp_sock *tp = tcp_sk(sk); 1434 u32 seq = tp->copied_seq; 1435 u32 offset; 1436 int copied = 0; 1437 1438 if (sk->sk_state == TCP_LISTEN) 1439 return -ENOTCONN; 1440 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { 1441 if (offset < skb->len) { 1442 int used; 1443 size_t len; 1444 1445 len = skb->len - offset; 1446 /* Stop reading if we hit a patch of urgent data */ 1447 if (tp->urg_data) { 1448 u32 urg_offset = tp->urg_seq - seq; 1449 if (urg_offset < len) 1450 len = urg_offset; 1451 if (!len) 1452 break; 1453 } 1454 used = recv_actor(desc, skb, offset, len); 1455 if (used < 0) { 1456 if (!copied) 1457 copied = used; 1458 break; 1459 } else if (used <= len) { 1460 seq += used; 1461 copied += used; 1462 offset += used; 1463 } 1464 /* 1465 * If recv_actor drops the lock (e.g. TCP splice 1466 * receive) the skb pointer might be invalid when 1467 * getting here: tcp_collapse might have deleted it 1468 * while aggregating skbs from the socket queue. 1469 */ 1470 skb = tcp_recv_skb(sk, seq-1, &offset); 1471 if (!skb || (offset+1 != skb->len)) 1472 break; 1473 } 1474 if (tcp_hdr(skb)->fin) { 1475 sk_eat_skb(sk, skb, false); 1476 ++seq; 1477 break; 1478 } 1479 sk_eat_skb(sk, skb, false); 1480 if (!desc->count) 1481 break; 1482 tp->copied_seq = seq; 1483 } 1484 tp->copied_seq = seq; 1485 1486 tcp_rcv_space_adjust(sk); 1487 1488 /* Clean up data we have read: This will do ACK frames. */ 1489 if (copied > 0) 1490 tcp_cleanup_rbuf(sk, copied); 1491 return copied; 1492 } 1493 EXPORT_SYMBOL(tcp_read_sock); 1494 1495 /* 1496 * This routine copies from a sock struct into the user buffer. 1497 * 1498 * Technical note: in 2.3 we work on _locked_ socket, so that 1499 * tricks with *seq access order and skb->users are not required. 1500 * Probably, code can be easily improved even more. 1501 */ 1502 1503 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 1504 size_t len, int nonblock, int flags, int *addr_len) 1505 { 1506 struct tcp_sock *tp = tcp_sk(sk); 1507 int copied = 0; 1508 u32 peek_seq; 1509 u32 *seq; 1510 unsigned long used; 1511 int err; 1512 int target; /* Read at least this many bytes */ 1513 long timeo; 1514 struct task_struct *user_recv = NULL; 1515 bool copied_early = false; 1516 struct sk_buff *skb; 1517 u32 urg_hole = 0; 1518 1519 lock_sock(sk); 1520 1521 err = -ENOTCONN; 1522 if (sk->sk_state == TCP_LISTEN) 1523 goto out; 1524 1525 timeo = sock_rcvtimeo(sk, nonblock); 1526 1527 /* Urgent data needs to be handled specially. */ 1528 if (flags & MSG_OOB) 1529 goto recv_urg; 1530 1531 if (unlikely(tp->repair)) { 1532 err = -EPERM; 1533 if (!(flags & MSG_PEEK)) 1534 goto out; 1535 1536 if (tp->repair_queue == TCP_SEND_QUEUE) 1537 goto recv_sndq; 1538 1539 err = -EINVAL; 1540 if (tp->repair_queue == TCP_NO_QUEUE) 1541 goto out; 1542 1543 /* 'common' recv queue MSG_PEEK-ing */ 1544 } 1545 1546 seq = &tp->copied_seq; 1547 if (flags & MSG_PEEK) { 1548 peek_seq = tp->copied_seq; 1549 seq = &peek_seq; 1550 } 1551 1552 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1553 1554 #ifdef CONFIG_NET_DMA 1555 tp->ucopy.dma_chan = NULL; 1556 preempt_disable(); 1557 skb = skb_peek_tail(&sk->sk_receive_queue); 1558 { 1559 int available = 0; 1560 1561 if (skb) 1562 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); 1563 if ((available < target) && 1564 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && 1565 !sysctl_tcp_low_latency && 1566 net_dma_find_channel()) { 1567 preempt_enable_no_resched(); 1568 tp->ucopy.pinned_list = 1569 dma_pin_iovec_pages(msg->msg_iov, len); 1570 } else { 1571 preempt_enable_no_resched(); 1572 } 1573 } 1574 #endif 1575 1576 do { 1577 u32 offset; 1578 1579 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ 1580 if (tp->urg_data && tp->urg_seq == *seq) { 1581 if (copied) 1582 break; 1583 if (signal_pending(current)) { 1584 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; 1585 break; 1586 } 1587 } 1588 1589 /* Next get a buffer. */ 1590 1591 skb_queue_walk(&sk->sk_receive_queue, skb) { 1592 /* Now that we have two receive queues this 1593 * shouldn't happen. 1594 */ 1595 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq), 1596 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n", 1597 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, 1598 flags)) 1599 break; 1600 1601 offset = *seq - TCP_SKB_CB(skb)->seq; 1602 if (tcp_hdr(skb)->syn) 1603 offset--; 1604 if (offset < skb->len) 1605 goto found_ok_skb; 1606 if (tcp_hdr(skb)->fin) 1607 goto found_fin_ok; 1608 WARN(!(flags & MSG_PEEK), 1609 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n", 1610 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags); 1611 } 1612 1613 /* Well, if we have backlog, try to process it now yet. */ 1614 1615 if (copied >= target && !sk->sk_backlog.tail) 1616 break; 1617 1618 if (copied) { 1619 if (sk->sk_err || 1620 sk->sk_state == TCP_CLOSE || 1621 (sk->sk_shutdown & RCV_SHUTDOWN) || 1622 !timeo || 1623 signal_pending(current)) 1624 break; 1625 } else { 1626 if (sock_flag(sk, SOCK_DONE)) 1627 break; 1628 1629 if (sk->sk_err) { 1630 copied = sock_error(sk); 1631 break; 1632 } 1633 1634 if (sk->sk_shutdown & RCV_SHUTDOWN) 1635 break; 1636 1637 if (sk->sk_state == TCP_CLOSE) { 1638 if (!sock_flag(sk, SOCK_DONE)) { 1639 /* This occurs when user tries to read 1640 * from never connected socket. 1641 */ 1642 copied = -ENOTCONN; 1643 break; 1644 } 1645 break; 1646 } 1647 1648 if (!timeo) { 1649 copied = -EAGAIN; 1650 break; 1651 } 1652 1653 if (signal_pending(current)) { 1654 copied = sock_intr_errno(timeo); 1655 break; 1656 } 1657 } 1658 1659 tcp_cleanup_rbuf(sk, copied); 1660 1661 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1662 /* Install new reader */ 1663 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1664 user_recv = current; 1665 tp->ucopy.task = user_recv; 1666 tp->ucopy.iov = msg->msg_iov; 1667 } 1668 1669 tp->ucopy.len = len; 1670 1671 WARN_ON(tp->copied_seq != tp->rcv_nxt && 1672 !(flags & (MSG_PEEK | MSG_TRUNC))); 1673 1674 /* Ugly... If prequeue is not empty, we have to 1675 * process it before releasing socket, otherwise 1676 * order will be broken at second iteration. 1677 * More elegant solution is required!!! 1678 * 1679 * Look: we have the following (pseudo)queues: 1680 * 1681 * 1. packets in flight 1682 * 2. backlog 1683 * 3. prequeue 1684 * 4. receive_queue 1685 * 1686 * Each queue can be processed only if the next ones 1687 * are empty. At this point we have empty receive_queue. 1688 * But prequeue _can_ be not empty after 2nd iteration, 1689 * when we jumped to start of loop because backlog 1690 * processing added something to receive_queue. 1691 * We cannot release_sock(), because backlog contains 1692 * packets arrived _after_ prequeued ones. 1693 * 1694 * Shortly, algorithm is clear --- to process all 1695 * the queues in order. We could make it more directly, 1696 * requeueing packets from backlog to prequeue, if 1697 * is not empty. It is more elegant, but eats cycles, 1698 * unfortunately. 1699 */ 1700 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1701 goto do_prequeue; 1702 1703 /* __ Set realtime policy in scheduler __ */ 1704 } 1705 1706 #ifdef CONFIG_NET_DMA 1707 if (tp->ucopy.dma_chan) 1708 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1709 #endif 1710 if (copied >= target) { 1711 /* Do not sleep, just process backlog. */ 1712 release_sock(sk); 1713 lock_sock(sk); 1714 } else 1715 sk_wait_data(sk, &timeo); 1716 1717 #ifdef CONFIG_NET_DMA 1718 tcp_service_net_dma(sk, false); /* Don't block */ 1719 tp->ucopy.wakeup = 0; 1720 #endif 1721 1722 if (user_recv) { 1723 int chunk; 1724 1725 /* __ Restore normal policy in scheduler __ */ 1726 1727 if ((chunk = len - tp->ucopy.len) != 0) { 1728 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1729 len -= chunk; 1730 copied += chunk; 1731 } 1732 1733 if (tp->rcv_nxt == tp->copied_seq && 1734 !skb_queue_empty(&tp->ucopy.prequeue)) { 1735 do_prequeue: 1736 tcp_prequeue_process(sk); 1737 1738 if ((chunk = len - tp->ucopy.len) != 0) { 1739 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1740 len -= chunk; 1741 copied += chunk; 1742 } 1743 } 1744 } 1745 if ((flags & MSG_PEEK) && 1746 (peek_seq - copied - urg_hole != tp->copied_seq)) { 1747 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n", 1748 current->comm, 1749 task_pid_nr(current)); 1750 peek_seq = tp->copied_seq; 1751 } 1752 continue; 1753 1754 found_ok_skb: 1755 /* Ok so how much can we use? */ 1756 used = skb->len - offset; 1757 if (len < used) 1758 used = len; 1759 1760 /* Do we have urgent data here? */ 1761 if (tp->urg_data) { 1762 u32 urg_offset = tp->urg_seq - *seq; 1763 if (urg_offset < used) { 1764 if (!urg_offset) { 1765 if (!sock_flag(sk, SOCK_URGINLINE)) { 1766 ++*seq; 1767 urg_hole++; 1768 offset++; 1769 used--; 1770 if (!used) 1771 goto skip_copy; 1772 } 1773 } else 1774 used = urg_offset; 1775 } 1776 } 1777 1778 if (!(flags & MSG_TRUNC)) { 1779 #ifdef CONFIG_NET_DMA 1780 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) 1781 tp->ucopy.dma_chan = net_dma_find_channel(); 1782 1783 if (tp->ucopy.dma_chan) { 1784 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec( 1785 tp->ucopy.dma_chan, skb, offset, 1786 msg->msg_iov, used, 1787 tp->ucopy.pinned_list); 1788 1789 if (tp->ucopy.dma_cookie < 0) { 1790 1791 pr_alert("%s: dma_cookie < 0\n", 1792 __func__); 1793 1794 /* Exception. Bailout! */ 1795 if (!copied) 1796 copied = -EFAULT; 1797 break; 1798 } 1799 1800 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1801 1802 if ((offset + used) == skb->len) 1803 copied_early = true; 1804 1805 } else 1806 #endif 1807 { 1808 err = skb_copy_datagram_iovec(skb, offset, 1809 msg->msg_iov, used); 1810 if (err) { 1811 /* Exception. Bailout! */ 1812 if (!copied) 1813 copied = -EFAULT; 1814 break; 1815 } 1816 } 1817 } 1818 1819 *seq += used; 1820 copied += used; 1821 len -= used; 1822 1823 tcp_rcv_space_adjust(sk); 1824 1825 skip_copy: 1826 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1827 tp->urg_data = 0; 1828 tcp_fast_path_check(sk); 1829 } 1830 if (used + offset < skb->len) 1831 continue; 1832 1833 if (tcp_hdr(skb)->fin) 1834 goto found_fin_ok; 1835 if (!(flags & MSG_PEEK)) { 1836 sk_eat_skb(sk, skb, copied_early); 1837 copied_early = false; 1838 } 1839 continue; 1840 1841 found_fin_ok: 1842 /* Process the FIN. */ 1843 ++*seq; 1844 if (!(flags & MSG_PEEK)) { 1845 sk_eat_skb(sk, skb, copied_early); 1846 copied_early = false; 1847 } 1848 break; 1849 } while (len > 0); 1850 1851 if (user_recv) { 1852 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1853 int chunk; 1854 1855 tp->ucopy.len = copied > 0 ? len : 0; 1856 1857 tcp_prequeue_process(sk); 1858 1859 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1860 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1861 len -= chunk; 1862 copied += chunk; 1863 } 1864 } 1865 1866 tp->ucopy.task = NULL; 1867 tp->ucopy.len = 0; 1868 } 1869 1870 #ifdef CONFIG_NET_DMA 1871 tcp_service_net_dma(sk, true); /* Wait for queue to drain */ 1872 tp->ucopy.dma_chan = NULL; 1873 1874 if (tp->ucopy.pinned_list) { 1875 dma_unpin_iovec_pages(tp->ucopy.pinned_list); 1876 tp->ucopy.pinned_list = NULL; 1877 } 1878 #endif 1879 1880 /* According to UNIX98, msg_name/msg_namelen are ignored 1881 * on connected socket. I was just happy when found this 8) --ANK 1882 */ 1883 1884 /* Clean up data we have read: This will do ACK frames. */ 1885 tcp_cleanup_rbuf(sk, copied); 1886 1887 release_sock(sk); 1888 return copied; 1889 1890 out: 1891 release_sock(sk); 1892 return err; 1893 1894 recv_urg: 1895 err = tcp_recv_urg(sk, msg, len, flags); 1896 goto out; 1897 1898 recv_sndq: 1899 err = tcp_peek_sndq(sk, msg, len); 1900 goto out; 1901 } 1902 EXPORT_SYMBOL(tcp_recvmsg); 1903 1904 void tcp_set_state(struct sock *sk, int state) 1905 { 1906 int oldstate = sk->sk_state; 1907 1908 switch (state) { 1909 case TCP_ESTABLISHED: 1910 if (oldstate != TCP_ESTABLISHED) 1911 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1912 break; 1913 1914 case TCP_CLOSE: 1915 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 1916 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS); 1917 1918 sk->sk_prot->unhash(sk); 1919 if (inet_csk(sk)->icsk_bind_hash && 1920 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 1921 inet_put_port(sk); 1922 /* fall through */ 1923 default: 1924 if (oldstate == TCP_ESTABLISHED) 1925 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1926 } 1927 1928 /* Change state AFTER socket is unhashed to avoid closed 1929 * socket sitting in hash tables. 1930 */ 1931 sk->sk_state = state; 1932 1933 #ifdef STATE_TRACE 1934 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]); 1935 #endif 1936 } 1937 EXPORT_SYMBOL_GPL(tcp_set_state); 1938 1939 /* 1940 * State processing on a close. This implements the state shift for 1941 * sending our FIN frame. Note that we only send a FIN for some 1942 * states. A shutdown() may have already sent the FIN, or we may be 1943 * closed. 1944 */ 1945 1946 static const unsigned char new_state[16] = { 1947 /* current state: new state: action: */ 1948 /* (Invalid) */ TCP_CLOSE, 1949 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1950 /* TCP_SYN_SENT */ TCP_CLOSE, 1951 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1952 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, 1953 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, 1954 /* TCP_TIME_WAIT */ TCP_CLOSE, 1955 /* TCP_CLOSE */ TCP_CLOSE, 1956 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, 1957 /* TCP_LAST_ACK */ TCP_LAST_ACK, 1958 /* TCP_LISTEN */ TCP_CLOSE, 1959 /* TCP_CLOSING */ TCP_CLOSING, 1960 }; 1961 1962 static int tcp_close_state(struct sock *sk) 1963 { 1964 int next = (int)new_state[sk->sk_state]; 1965 int ns = next & TCP_STATE_MASK; 1966 1967 tcp_set_state(sk, ns); 1968 1969 return next & TCP_ACTION_FIN; 1970 } 1971 1972 /* 1973 * Shutdown the sending side of a connection. Much like close except 1974 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD). 1975 */ 1976 1977 void tcp_shutdown(struct sock *sk, int how) 1978 { 1979 /* We need to grab some memory, and put together a FIN, 1980 * and then put it into the queue to be sent. 1981 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 1982 */ 1983 if (!(how & SEND_SHUTDOWN)) 1984 return; 1985 1986 /* If we've already sent a FIN, or it's a closed state, skip this. */ 1987 if ((1 << sk->sk_state) & 1988 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 1989 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 1990 /* Clear out any half completed packets. FIN if needed. */ 1991 if (tcp_close_state(sk)) 1992 tcp_send_fin(sk); 1993 } 1994 } 1995 EXPORT_SYMBOL(tcp_shutdown); 1996 1997 bool tcp_check_oom(struct sock *sk, int shift) 1998 { 1999 bool too_many_orphans, out_of_socket_memory; 2000 2001 too_many_orphans = tcp_too_many_orphans(sk, shift); 2002 out_of_socket_memory = tcp_out_of_memory(sk); 2003 2004 if (too_many_orphans) 2005 net_info_ratelimited("too many orphaned sockets\n"); 2006 if (out_of_socket_memory) 2007 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n"); 2008 return too_many_orphans || out_of_socket_memory; 2009 } 2010 2011 void tcp_close(struct sock *sk, long timeout) 2012 { 2013 struct sk_buff *skb; 2014 int data_was_unread = 0; 2015 int state; 2016 2017 lock_sock(sk); 2018 sk->sk_shutdown = SHUTDOWN_MASK; 2019 2020 if (sk->sk_state == TCP_LISTEN) { 2021 tcp_set_state(sk, TCP_CLOSE); 2022 2023 /* Special case. */ 2024 inet_csk_listen_stop(sk); 2025 2026 goto adjudge_to_death; 2027 } 2028 2029 /* We need to flush the recv. buffs. We do this only on the 2030 * descriptor close, not protocol-sourced closes, because the 2031 * reader process may not have drained the data yet! 2032 */ 2033 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 2034 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq - 2035 tcp_hdr(skb)->fin; 2036 data_was_unread += len; 2037 __kfree_skb(skb); 2038 } 2039 2040 sk_mem_reclaim(sk); 2041 2042 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */ 2043 if (sk->sk_state == TCP_CLOSE) 2044 goto adjudge_to_death; 2045 2046 /* As outlined in RFC 2525, section 2.17, we send a RST here because 2047 * data was lost. To witness the awful effects of the old behavior of 2048 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk 2049 * GET in an FTP client, suspend the process, wait for the client to 2050 * advertise a zero window, then kill -9 the FTP client, wheee... 2051 * Note: timeout is always zero in such a case. 2052 */ 2053 if (unlikely(tcp_sk(sk)->repair)) { 2054 sk->sk_prot->disconnect(sk, 0); 2055 } else if (data_was_unread) { 2056 /* Unread data was tossed, zap the connection. */ 2057 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE); 2058 tcp_set_state(sk, TCP_CLOSE); 2059 tcp_send_active_reset(sk, sk->sk_allocation); 2060 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 2061 /* Check zero linger _after_ checking for unread data. */ 2062 sk->sk_prot->disconnect(sk, 0); 2063 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA); 2064 } else if (tcp_close_state(sk)) { 2065 /* We FIN if the application ate all the data before 2066 * zapping the connection. 2067 */ 2068 2069 /* RED-PEN. Formally speaking, we have broken TCP state 2070 * machine. State transitions: 2071 * 2072 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 2073 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 2074 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 2075 * 2076 * are legal only when FIN has been sent (i.e. in window), 2077 * rather than queued out of window. Purists blame. 2078 * 2079 * F.e. "RFC state" is ESTABLISHED, 2080 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 2081 * 2082 * The visible declinations are that sometimes 2083 * we enter time-wait state, when it is not required really 2084 * (harmless), do not send active resets, when they are 2085 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 2086 * they look as CLOSING or LAST_ACK for Linux) 2087 * Probably, I missed some more holelets. 2088 * --ANK 2089 */ 2090 tcp_send_fin(sk); 2091 } 2092 2093 sk_stream_wait_close(sk, timeout); 2094 2095 adjudge_to_death: 2096 state = sk->sk_state; 2097 sock_hold(sk); 2098 sock_orphan(sk); 2099 2100 /* It is the last release_sock in its life. It will remove backlog. */ 2101 release_sock(sk); 2102 2103 2104 /* Now socket is owned by kernel and we acquire BH lock 2105 to finish close. No need to check for user refs. 2106 */ 2107 local_bh_disable(); 2108 bh_lock_sock(sk); 2109 WARN_ON(sock_owned_by_user(sk)); 2110 2111 percpu_counter_inc(sk->sk_prot->orphan_count); 2112 2113 /* Have we already been destroyed by a softirq or backlog? */ 2114 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) 2115 goto out; 2116 2117 /* This is a (useful) BSD violating of the RFC. There is a 2118 * problem with TCP as specified in that the other end could 2119 * keep a socket open forever with no application left this end. 2120 * We use a 3 minute timeout (about the same as BSD) then kill 2121 * our end. If they send after that then tough - BUT: long enough 2122 * that we won't make the old 4*rto = almost no time - whoops 2123 * reset mistake. 2124 * 2125 * Nope, it was not mistake. It is really desired behaviour 2126 * f.e. on http servers, when such sockets are useless, but 2127 * consume significant resources. Let's do it with special 2128 * linger2 option. --ANK 2129 */ 2130 2131 if (sk->sk_state == TCP_FIN_WAIT2) { 2132 struct tcp_sock *tp = tcp_sk(sk); 2133 if (tp->linger2 < 0) { 2134 tcp_set_state(sk, TCP_CLOSE); 2135 tcp_send_active_reset(sk, GFP_ATOMIC); 2136 NET_INC_STATS_BH(sock_net(sk), 2137 LINUX_MIB_TCPABORTONLINGER); 2138 } else { 2139 const int tmo = tcp_fin_time(sk); 2140 2141 if (tmo > TCP_TIMEWAIT_LEN) { 2142 inet_csk_reset_keepalive_timer(sk, 2143 tmo - TCP_TIMEWAIT_LEN); 2144 } else { 2145 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); 2146 goto out; 2147 } 2148 } 2149 } 2150 if (sk->sk_state != TCP_CLOSE) { 2151 sk_mem_reclaim(sk); 2152 if (tcp_check_oom(sk, 0)) { 2153 tcp_set_state(sk, TCP_CLOSE); 2154 tcp_send_active_reset(sk, GFP_ATOMIC); 2155 NET_INC_STATS_BH(sock_net(sk), 2156 LINUX_MIB_TCPABORTONMEMORY); 2157 } 2158 } 2159 2160 if (sk->sk_state == TCP_CLOSE) 2161 inet_csk_destroy_sock(sk); 2162 /* Otherwise, socket is reprieved until protocol close. */ 2163 2164 out: 2165 bh_unlock_sock(sk); 2166 local_bh_enable(); 2167 sock_put(sk); 2168 } 2169 EXPORT_SYMBOL(tcp_close); 2170 2171 /* These states need RST on ABORT according to RFC793 */ 2172 2173 static inline bool tcp_need_reset(int state) 2174 { 2175 return (1 << state) & 2176 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 2177 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 2178 } 2179 2180 int tcp_disconnect(struct sock *sk, int flags) 2181 { 2182 struct inet_sock *inet = inet_sk(sk); 2183 struct inet_connection_sock *icsk = inet_csk(sk); 2184 struct tcp_sock *tp = tcp_sk(sk); 2185 int err = 0; 2186 int old_state = sk->sk_state; 2187 2188 if (old_state != TCP_CLOSE) 2189 tcp_set_state(sk, TCP_CLOSE); 2190 2191 /* ABORT function of RFC793 */ 2192 if (old_state == TCP_LISTEN) { 2193 inet_csk_listen_stop(sk); 2194 } else if (unlikely(tp->repair)) { 2195 sk->sk_err = ECONNABORTED; 2196 } else if (tcp_need_reset(old_state) || 2197 (tp->snd_nxt != tp->write_seq && 2198 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 2199 /* The last check adjusts for discrepancy of Linux wrt. RFC 2200 * states 2201 */ 2202 tcp_send_active_reset(sk, gfp_any()); 2203 sk->sk_err = ECONNRESET; 2204 } else if (old_state == TCP_SYN_SENT) 2205 sk->sk_err = ECONNRESET; 2206 2207 tcp_clear_xmit_timers(sk); 2208 __skb_queue_purge(&sk->sk_receive_queue); 2209 tcp_write_queue_purge(sk); 2210 __skb_queue_purge(&tp->out_of_order_queue); 2211 #ifdef CONFIG_NET_DMA 2212 __skb_queue_purge(&sk->sk_async_wait_queue); 2213 #endif 2214 2215 inet->inet_dport = 0; 2216 2217 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 2218 inet_reset_saddr(sk); 2219 2220 sk->sk_shutdown = 0; 2221 sock_reset_flag(sk, SOCK_DONE); 2222 tp->srtt = 0; 2223 if ((tp->write_seq += tp->max_window + 2) == 0) 2224 tp->write_seq = 1; 2225 icsk->icsk_backoff = 0; 2226 tp->snd_cwnd = 2; 2227 icsk->icsk_probes_out = 0; 2228 tp->packets_out = 0; 2229 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 2230 tp->snd_cwnd_cnt = 0; 2231 tp->bytes_acked = 0; 2232 tp->window_clamp = 0; 2233 tcp_set_ca_state(sk, TCP_CA_Open); 2234 tcp_clear_retrans(tp); 2235 inet_csk_delack_init(sk); 2236 tcp_init_send_head(sk); 2237 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); 2238 __sk_dst_reset(sk); 2239 2240 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash); 2241 2242 sk->sk_error_report(sk); 2243 return err; 2244 } 2245 EXPORT_SYMBOL(tcp_disconnect); 2246 2247 static inline bool tcp_can_repair_sock(const struct sock *sk) 2248 { 2249 return capable(CAP_NET_ADMIN) && 2250 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED)); 2251 } 2252 2253 static int tcp_repair_options_est(struct tcp_sock *tp, 2254 struct tcp_repair_opt __user *optbuf, unsigned int len) 2255 { 2256 struct tcp_repair_opt opt; 2257 2258 while (len >= sizeof(opt)) { 2259 if (copy_from_user(&opt, optbuf, sizeof(opt))) 2260 return -EFAULT; 2261 2262 optbuf++; 2263 len -= sizeof(opt); 2264 2265 switch (opt.opt_code) { 2266 case TCPOPT_MSS: 2267 tp->rx_opt.mss_clamp = opt.opt_val; 2268 break; 2269 case TCPOPT_WINDOW: 2270 if (opt.opt_val > 14) 2271 return -EFBIG; 2272 2273 tp->rx_opt.snd_wscale = opt.opt_val; 2274 break; 2275 case TCPOPT_SACK_PERM: 2276 if (opt.opt_val != 0) 2277 return -EINVAL; 2278 2279 tp->rx_opt.sack_ok |= TCP_SACK_SEEN; 2280 if (sysctl_tcp_fack) 2281 tcp_enable_fack(tp); 2282 break; 2283 case TCPOPT_TIMESTAMP: 2284 if (opt.opt_val != 0) 2285 return -EINVAL; 2286 2287 tp->rx_opt.tstamp_ok = 1; 2288 break; 2289 } 2290 } 2291 2292 return 0; 2293 } 2294 2295 /* 2296 * Socket option code for TCP. 2297 */ 2298 static int do_tcp_setsockopt(struct sock *sk, int level, 2299 int optname, char __user *optval, unsigned int optlen) 2300 { 2301 struct tcp_sock *tp = tcp_sk(sk); 2302 struct inet_connection_sock *icsk = inet_csk(sk); 2303 int val; 2304 int err = 0; 2305 2306 /* These are data/string values, all the others are ints */ 2307 switch (optname) { 2308 case TCP_CONGESTION: { 2309 char name[TCP_CA_NAME_MAX]; 2310 2311 if (optlen < 1) 2312 return -EINVAL; 2313 2314 val = strncpy_from_user(name, optval, 2315 min_t(long, TCP_CA_NAME_MAX-1, optlen)); 2316 if (val < 0) 2317 return -EFAULT; 2318 name[val] = 0; 2319 2320 lock_sock(sk); 2321 err = tcp_set_congestion_control(sk, name); 2322 release_sock(sk); 2323 return err; 2324 } 2325 case TCP_COOKIE_TRANSACTIONS: { 2326 struct tcp_cookie_transactions ctd; 2327 struct tcp_cookie_values *cvp = NULL; 2328 2329 if (sizeof(ctd) > optlen) 2330 return -EINVAL; 2331 if (copy_from_user(&ctd, optval, sizeof(ctd))) 2332 return -EFAULT; 2333 2334 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) || 2335 ctd.tcpct_s_data_desired > TCP_MSS_DESIRED) 2336 return -EINVAL; 2337 2338 if (ctd.tcpct_cookie_desired == 0) { 2339 /* default to global value */ 2340 } else if ((0x1 & ctd.tcpct_cookie_desired) || 2341 ctd.tcpct_cookie_desired > TCP_COOKIE_MAX || 2342 ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) { 2343 return -EINVAL; 2344 } 2345 2346 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) { 2347 /* Supercedes all other values */ 2348 lock_sock(sk); 2349 if (tp->cookie_values != NULL) { 2350 kref_put(&tp->cookie_values->kref, 2351 tcp_cookie_values_release); 2352 tp->cookie_values = NULL; 2353 } 2354 tp->rx_opt.cookie_in_always = 0; /* false */ 2355 tp->rx_opt.cookie_out_never = 1; /* true */ 2356 release_sock(sk); 2357 return err; 2358 } 2359 2360 /* Allocate ancillary memory before locking. 2361 */ 2362 if (ctd.tcpct_used > 0 || 2363 (tp->cookie_values == NULL && 2364 (sysctl_tcp_cookie_size > 0 || 2365 ctd.tcpct_cookie_desired > 0 || 2366 ctd.tcpct_s_data_desired > 0))) { 2367 cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used, 2368 GFP_KERNEL); 2369 if (cvp == NULL) 2370 return -ENOMEM; 2371 2372 kref_init(&cvp->kref); 2373 } 2374 lock_sock(sk); 2375 tp->rx_opt.cookie_in_always = 2376 (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags); 2377 tp->rx_opt.cookie_out_never = 0; /* false */ 2378 2379 if (tp->cookie_values != NULL) { 2380 if (cvp != NULL) { 2381 /* Changed values are recorded by a changed 2382 * pointer, ensuring the cookie will differ, 2383 * without separately hashing each value later. 2384 */ 2385 kref_put(&tp->cookie_values->kref, 2386 tcp_cookie_values_release); 2387 } else { 2388 cvp = tp->cookie_values; 2389 } 2390 } 2391 2392 if (cvp != NULL) { 2393 cvp->cookie_desired = ctd.tcpct_cookie_desired; 2394 2395 if (ctd.tcpct_used > 0) { 2396 memcpy(cvp->s_data_payload, ctd.tcpct_value, 2397 ctd.tcpct_used); 2398 cvp->s_data_desired = ctd.tcpct_used; 2399 cvp->s_data_constant = 1; /* true */ 2400 } else { 2401 /* No constant payload data. */ 2402 cvp->s_data_desired = ctd.tcpct_s_data_desired; 2403 cvp->s_data_constant = 0; /* false */ 2404 } 2405 2406 tp->cookie_values = cvp; 2407 } 2408 release_sock(sk); 2409 return err; 2410 } 2411 default: 2412 /* fallthru */ 2413 break; 2414 } 2415 2416 if (optlen < sizeof(int)) 2417 return -EINVAL; 2418 2419 if (get_user(val, (int __user *)optval)) 2420 return -EFAULT; 2421 2422 lock_sock(sk); 2423 2424 switch (optname) { 2425 case TCP_MAXSEG: 2426 /* Values greater than interface MTU won't take effect. However 2427 * at the point when this call is done we typically don't yet 2428 * know which interface is going to be used */ 2429 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) { 2430 err = -EINVAL; 2431 break; 2432 } 2433 tp->rx_opt.user_mss = val; 2434 break; 2435 2436 case TCP_NODELAY: 2437 if (val) { 2438 /* TCP_NODELAY is weaker than TCP_CORK, so that 2439 * this option on corked socket is remembered, but 2440 * it is not activated until cork is cleared. 2441 * 2442 * However, when TCP_NODELAY is set we make 2443 * an explicit push, which overrides even TCP_CORK 2444 * for currently queued segments. 2445 */ 2446 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 2447 tcp_push_pending_frames(sk); 2448 } else { 2449 tp->nonagle &= ~TCP_NAGLE_OFF; 2450 } 2451 break; 2452 2453 case TCP_THIN_LINEAR_TIMEOUTS: 2454 if (val < 0 || val > 1) 2455 err = -EINVAL; 2456 else 2457 tp->thin_lto = val; 2458 break; 2459 2460 case TCP_THIN_DUPACK: 2461 if (val < 0 || val > 1) 2462 err = -EINVAL; 2463 else 2464 tp->thin_dupack = val; 2465 if (tp->thin_dupack) 2466 tcp_disable_early_retrans(tp); 2467 break; 2468 2469 case TCP_REPAIR: 2470 if (!tcp_can_repair_sock(sk)) 2471 err = -EPERM; 2472 else if (val == 1) { 2473 tp->repair = 1; 2474 sk->sk_reuse = SK_FORCE_REUSE; 2475 tp->repair_queue = TCP_NO_QUEUE; 2476 } else if (val == 0) { 2477 tp->repair = 0; 2478 sk->sk_reuse = SK_NO_REUSE; 2479 tcp_send_window_probe(sk); 2480 } else 2481 err = -EINVAL; 2482 2483 break; 2484 2485 case TCP_REPAIR_QUEUE: 2486 if (!tp->repair) 2487 err = -EPERM; 2488 else if (val < TCP_QUEUES_NR) 2489 tp->repair_queue = val; 2490 else 2491 err = -EINVAL; 2492 break; 2493 2494 case TCP_QUEUE_SEQ: 2495 if (sk->sk_state != TCP_CLOSE) 2496 err = -EPERM; 2497 else if (tp->repair_queue == TCP_SEND_QUEUE) 2498 tp->write_seq = val; 2499 else if (tp->repair_queue == TCP_RECV_QUEUE) 2500 tp->rcv_nxt = val; 2501 else 2502 err = -EINVAL; 2503 break; 2504 2505 case TCP_REPAIR_OPTIONS: 2506 if (!tp->repair) 2507 err = -EINVAL; 2508 else if (sk->sk_state == TCP_ESTABLISHED) 2509 err = tcp_repair_options_est(tp, 2510 (struct tcp_repair_opt __user *)optval, 2511 optlen); 2512 else 2513 err = -EPERM; 2514 break; 2515 2516 case TCP_CORK: 2517 /* When set indicates to always queue non-full frames. 2518 * Later the user clears this option and we transmit 2519 * any pending partial frames in the queue. This is 2520 * meant to be used alongside sendfile() to get properly 2521 * filled frames when the user (for example) must write 2522 * out headers with a write() call first and then use 2523 * sendfile to send out the data parts. 2524 * 2525 * TCP_CORK can be set together with TCP_NODELAY and it is 2526 * stronger than TCP_NODELAY. 2527 */ 2528 if (val) { 2529 tp->nonagle |= TCP_NAGLE_CORK; 2530 } else { 2531 tp->nonagle &= ~TCP_NAGLE_CORK; 2532 if (tp->nonagle&TCP_NAGLE_OFF) 2533 tp->nonagle |= TCP_NAGLE_PUSH; 2534 tcp_push_pending_frames(sk); 2535 } 2536 break; 2537 2538 case TCP_KEEPIDLE: 2539 if (val < 1 || val > MAX_TCP_KEEPIDLE) 2540 err = -EINVAL; 2541 else { 2542 tp->keepalive_time = val * HZ; 2543 if (sock_flag(sk, SOCK_KEEPOPEN) && 2544 !((1 << sk->sk_state) & 2545 (TCPF_CLOSE | TCPF_LISTEN))) { 2546 u32 elapsed = keepalive_time_elapsed(tp); 2547 if (tp->keepalive_time > elapsed) 2548 elapsed = tp->keepalive_time - elapsed; 2549 else 2550 elapsed = 0; 2551 inet_csk_reset_keepalive_timer(sk, elapsed); 2552 } 2553 } 2554 break; 2555 case TCP_KEEPINTVL: 2556 if (val < 1 || val > MAX_TCP_KEEPINTVL) 2557 err = -EINVAL; 2558 else 2559 tp->keepalive_intvl = val * HZ; 2560 break; 2561 case TCP_KEEPCNT: 2562 if (val < 1 || val > MAX_TCP_KEEPCNT) 2563 err = -EINVAL; 2564 else 2565 tp->keepalive_probes = val; 2566 break; 2567 case TCP_SYNCNT: 2568 if (val < 1 || val > MAX_TCP_SYNCNT) 2569 err = -EINVAL; 2570 else 2571 icsk->icsk_syn_retries = val; 2572 break; 2573 2574 case TCP_LINGER2: 2575 if (val < 0) 2576 tp->linger2 = -1; 2577 else if (val > sysctl_tcp_fin_timeout / HZ) 2578 tp->linger2 = 0; 2579 else 2580 tp->linger2 = val * HZ; 2581 break; 2582 2583 case TCP_DEFER_ACCEPT: 2584 /* Translate value in seconds to number of retransmits */ 2585 icsk->icsk_accept_queue.rskq_defer_accept = 2586 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ, 2587 TCP_RTO_MAX / HZ); 2588 break; 2589 2590 case TCP_WINDOW_CLAMP: 2591 if (!val) { 2592 if (sk->sk_state != TCP_CLOSE) { 2593 err = -EINVAL; 2594 break; 2595 } 2596 tp->window_clamp = 0; 2597 } else 2598 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 2599 SOCK_MIN_RCVBUF / 2 : val; 2600 break; 2601 2602 case TCP_QUICKACK: 2603 if (!val) { 2604 icsk->icsk_ack.pingpong = 1; 2605 } else { 2606 icsk->icsk_ack.pingpong = 0; 2607 if ((1 << sk->sk_state) & 2608 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 2609 inet_csk_ack_scheduled(sk)) { 2610 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 2611 tcp_cleanup_rbuf(sk, 1); 2612 if (!(val & 1)) 2613 icsk->icsk_ack.pingpong = 1; 2614 } 2615 } 2616 break; 2617 2618 #ifdef CONFIG_TCP_MD5SIG 2619 case TCP_MD5SIG: 2620 /* Read the IP->Key mappings from userspace */ 2621 err = tp->af_specific->md5_parse(sk, optval, optlen); 2622 break; 2623 #endif 2624 case TCP_USER_TIMEOUT: 2625 /* Cap the max timeout in ms TCP will retry/retrans 2626 * before giving up and aborting (ETIMEDOUT) a connection. 2627 */ 2628 icsk->icsk_user_timeout = msecs_to_jiffies(val); 2629 break; 2630 default: 2631 err = -ENOPROTOOPT; 2632 break; 2633 } 2634 2635 release_sock(sk); 2636 return err; 2637 } 2638 2639 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 2640 unsigned int optlen) 2641 { 2642 const struct inet_connection_sock *icsk = inet_csk(sk); 2643 2644 if (level != SOL_TCP) 2645 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 2646 optval, optlen); 2647 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2648 } 2649 EXPORT_SYMBOL(tcp_setsockopt); 2650 2651 #ifdef CONFIG_COMPAT 2652 int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 2653 char __user *optval, unsigned int optlen) 2654 { 2655 if (level != SOL_TCP) 2656 return inet_csk_compat_setsockopt(sk, level, optname, 2657 optval, optlen); 2658 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2659 } 2660 EXPORT_SYMBOL(compat_tcp_setsockopt); 2661 #endif 2662 2663 /* Return information about state of tcp endpoint in API format. */ 2664 void tcp_get_info(const struct sock *sk, struct tcp_info *info) 2665 { 2666 const struct tcp_sock *tp = tcp_sk(sk); 2667 const struct inet_connection_sock *icsk = inet_csk(sk); 2668 u32 now = tcp_time_stamp; 2669 2670 memset(info, 0, sizeof(*info)); 2671 2672 info->tcpi_state = sk->sk_state; 2673 info->tcpi_ca_state = icsk->icsk_ca_state; 2674 info->tcpi_retransmits = icsk->icsk_retransmits; 2675 info->tcpi_probes = icsk->icsk_probes_out; 2676 info->tcpi_backoff = icsk->icsk_backoff; 2677 2678 if (tp->rx_opt.tstamp_ok) 2679 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2680 if (tcp_is_sack(tp)) 2681 info->tcpi_options |= TCPI_OPT_SACK; 2682 if (tp->rx_opt.wscale_ok) { 2683 info->tcpi_options |= TCPI_OPT_WSCALE; 2684 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2685 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2686 } 2687 2688 if (tp->ecn_flags & TCP_ECN_OK) 2689 info->tcpi_options |= TCPI_OPT_ECN; 2690 if (tp->ecn_flags & TCP_ECN_SEEN) 2691 info->tcpi_options |= TCPI_OPT_ECN_SEEN; 2692 2693 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2694 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2695 info->tcpi_snd_mss = tp->mss_cache; 2696 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2697 2698 if (sk->sk_state == TCP_LISTEN) { 2699 info->tcpi_unacked = sk->sk_ack_backlog; 2700 info->tcpi_sacked = sk->sk_max_ack_backlog; 2701 } else { 2702 info->tcpi_unacked = tp->packets_out; 2703 info->tcpi_sacked = tp->sacked_out; 2704 } 2705 info->tcpi_lost = tp->lost_out; 2706 info->tcpi_retrans = tp->retrans_out; 2707 info->tcpi_fackets = tp->fackets_out; 2708 2709 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2710 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2711 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2712 2713 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2714 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2715 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3; 2716 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2; 2717 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2718 info->tcpi_snd_cwnd = tp->snd_cwnd; 2719 info->tcpi_advmss = tp->advmss; 2720 info->tcpi_reordering = tp->reordering; 2721 2722 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2723 info->tcpi_rcv_space = tp->rcvq_space.space; 2724 2725 info->tcpi_total_retrans = tp->total_retrans; 2726 } 2727 EXPORT_SYMBOL_GPL(tcp_get_info); 2728 2729 static int do_tcp_getsockopt(struct sock *sk, int level, 2730 int optname, char __user *optval, int __user *optlen) 2731 { 2732 struct inet_connection_sock *icsk = inet_csk(sk); 2733 struct tcp_sock *tp = tcp_sk(sk); 2734 int val, len; 2735 2736 if (get_user(len, optlen)) 2737 return -EFAULT; 2738 2739 len = min_t(unsigned int, len, sizeof(int)); 2740 2741 if (len < 0) 2742 return -EINVAL; 2743 2744 switch (optname) { 2745 case TCP_MAXSEG: 2746 val = tp->mss_cache; 2747 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2748 val = tp->rx_opt.user_mss; 2749 if (tp->repair) 2750 val = tp->rx_opt.mss_clamp; 2751 break; 2752 case TCP_NODELAY: 2753 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2754 break; 2755 case TCP_CORK: 2756 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2757 break; 2758 case TCP_KEEPIDLE: 2759 val = keepalive_time_when(tp) / HZ; 2760 break; 2761 case TCP_KEEPINTVL: 2762 val = keepalive_intvl_when(tp) / HZ; 2763 break; 2764 case TCP_KEEPCNT: 2765 val = keepalive_probes(tp); 2766 break; 2767 case TCP_SYNCNT: 2768 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2769 break; 2770 case TCP_LINGER2: 2771 val = tp->linger2; 2772 if (val >= 0) 2773 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2774 break; 2775 case TCP_DEFER_ACCEPT: 2776 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept, 2777 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ); 2778 break; 2779 case TCP_WINDOW_CLAMP: 2780 val = tp->window_clamp; 2781 break; 2782 case TCP_INFO: { 2783 struct tcp_info info; 2784 2785 if (get_user(len, optlen)) 2786 return -EFAULT; 2787 2788 tcp_get_info(sk, &info); 2789 2790 len = min_t(unsigned int, len, sizeof(info)); 2791 if (put_user(len, optlen)) 2792 return -EFAULT; 2793 if (copy_to_user(optval, &info, len)) 2794 return -EFAULT; 2795 return 0; 2796 } 2797 case TCP_QUICKACK: 2798 val = !icsk->icsk_ack.pingpong; 2799 break; 2800 2801 case TCP_CONGESTION: 2802 if (get_user(len, optlen)) 2803 return -EFAULT; 2804 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2805 if (put_user(len, optlen)) 2806 return -EFAULT; 2807 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2808 return -EFAULT; 2809 return 0; 2810 2811 case TCP_COOKIE_TRANSACTIONS: { 2812 struct tcp_cookie_transactions ctd; 2813 struct tcp_cookie_values *cvp = tp->cookie_values; 2814 2815 if (get_user(len, optlen)) 2816 return -EFAULT; 2817 if (len < sizeof(ctd)) 2818 return -EINVAL; 2819 2820 memset(&ctd, 0, sizeof(ctd)); 2821 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ? 2822 TCP_COOKIE_IN_ALWAYS : 0) 2823 | (tp->rx_opt.cookie_out_never ? 2824 TCP_COOKIE_OUT_NEVER : 0); 2825 2826 if (cvp != NULL) { 2827 ctd.tcpct_flags |= (cvp->s_data_in ? 2828 TCP_S_DATA_IN : 0) 2829 | (cvp->s_data_out ? 2830 TCP_S_DATA_OUT : 0); 2831 2832 ctd.tcpct_cookie_desired = cvp->cookie_desired; 2833 ctd.tcpct_s_data_desired = cvp->s_data_desired; 2834 2835 memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0], 2836 cvp->cookie_pair_size); 2837 ctd.tcpct_used = cvp->cookie_pair_size; 2838 } 2839 2840 if (put_user(sizeof(ctd), optlen)) 2841 return -EFAULT; 2842 if (copy_to_user(optval, &ctd, sizeof(ctd))) 2843 return -EFAULT; 2844 return 0; 2845 } 2846 case TCP_THIN_LINEAR_TIMEOUTS: 2847 val = tp->thin_lto; 2848 break; 2849 case TCP_THIN_DUPACK: 2850 val = tp->thin_dupack; 2851 break; 2852 2853 case TCP_REPAIR: 2854 val = tp->repair; 2855 break; 2856 2857 case TCP_REPAIR_QUEUE: 2858 if (tp->repair) 2859 val = tp->repair_queue; 2860 else 2861 return -EINVAL; 2862 break; 2863 2864 case TCP_QUEUE_SEQ: 2865 if (tp->repair_queue == TCP_SEND_QUEUE) 2866 val = tp->write_seq; 2867 else if (tp->repair_queue == TCP_RECV_QUEUE) 2868 val = tp->rcv_nxt; 2869 else 2870 return -EINVAL; 2871 break; 2872 2873 case TCP_USER_TIMEOUT: 2874 val = jiffies_to_msecs(icsk->icsk_user_timeout); 2875 break; 2876 default: 2877 return -ENOPROTOOPT; 2878 } 2879 2880 if (put_user(len, optlen)) 2881 return -EFAULT; 2882 if (copy_to_user(optval, &val, len)) 2883 return -EFAULT; 2884 return 0; 2885 } 2886 2887 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2888 int __user *optlen) 2889 { 2890 struct inet_connection_sock *icsk = inet_csk(sk); 2891 2892 if (level != SOL_TCP) 2893 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2894 optval, optlen); 2895 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2896 } 2897 EXPORT_SYMBOL(tcp_getsockopt); 2898 2899 #ifdef CONFIG_COMPAT 2900 int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2901 char __user *optval, int __user *optlen) 2902 { 2903 if (level != SOL_TCP) 2904 return inet_csk_compat_getsockopt(sk, level, optname, 2905 optval, optlen); 2906 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2907 } 2908 EXPORT_SYMBOL(compat_tcp_getsockopt); 2909 #endif 2910 2911 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, 2912 netdev_features_t features) 2913 { 2914 struct sk_buff *segs = ERR_PTR(-EINVAL); 2915 struct tcphdr *th; 2916 unsigned int thlen; 2917 unsigned int seq; 2918 __be32 delta; 2919 unsigned int oldlen; 2920 unsigned int mss; 2921 2922 if (!pskb_may_pull(skb, sizeof(*th))) 2923 goto out; 2924 2925 th = tcp_hdr(skb); 2926 thlen = th->doff * 4; 2927 if (thlen < sizeof(*th)) 2928 goto out; 2929 2930 if (!pskb_may_pull(skb, thlen)) 2931 goto out; 2932 2933 oldlen = (u16)~skb->len; 2934 __skb_pull(skb, thlen); 2935 2936 mss = skb_shinfo(skb)->gso_size; 2937 if (unlikely(skb->len <= mss)) 2938 goto out; 2939 2940 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 2941 /* Packet is from an untrusted source, reset gso_segs. */ 2942 int type = skb_shinfo(skb)->gso_type; 2943 2944 if (unlikely(type & 2945 ~(SKB_GSO_TCPV4 | 2946 SKB_GSO_DODGY | 2947 SKB_GSO_TCP_ECN | 2948 SKB_GSO_TCPV6 | 2949 0) || 2950 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) 2951 goto out; 2952 2953 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); 2954 2955 segs = NULL; 2956 goto out; 2957 } 2958 2959 segs = skb_segment(skb, features); 2960 if (IS_ERR(segs)) 2961 goto out; 2962 2963 delta = htonl(oldlen + (thlen + mss)); 2964 2965 skb = segs; 2966 th = tcp_hdr(skb); 2967 seq = ntohl(th->seq); 2968 2969 do { 2970 th->fin = th->psh = 0; 2971 2972 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2973 (__force u32)delta)); 2974 if (skb->ip_summed != CHECKSUM_PARTIAL) 2975 th->check = 2976 csum_fold(csum_partial(skb_transport_header(skb), 2977 thlen, skb->csum)); 2978 2979 seq += mss; 2980 skb = skb->next; 2981 th = tcp_hdr(skb); 2982 2983 th->seq = htonl(seq); 2984 th->cwr = 0; 2985 } while (skb->next); 2986 2987 delta = htonl(oldlen + (skb->tail - skb->transport_header) + 2988 skb->data_len); 2989 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 2990 (__force u32)delta)); 2991 if (skb->ip_summed != CHECKSUM_PARTIAL) 2992 th->check = csum_fold(csum_partial(skb_transport_header(skb), 2993 thlen, skb->csum)); 2994 2995 out: 2996 return segs; 2997 } 2998 EXPORT_SYMBOL(tcp_tso_segment); 2999 3000 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) 3001 { 3002 struct sk_buff **pp = NULL; 3003 struct sk_buff *p; 3004 struct tcphdr *th; 3005 struct tcphdr *th2; 3006 unsigned int len; 3007 unsigned int thlen; 3008 __be32 flags; 3009 unsigned int mss = 1; 3010 unsigned int hlen; 3011 unsigned int off; 3012 int flush = 1; 3013 int i; 3014 3015 off = skb_gro_offset(skb); 3016 hlen = off + sizeof(*th); 3017 th = skb_gro_header_fast(skb, off); 3018 if (skb_gro_header_hard(skb, hlen)) { 3019 th = skb_gro_header_slow(skb, hlen, off); 3020 if (unlikely(!th)) 3021 goto out; 3022 } 3023 3024 thlen = th->doff * 4; 3025 if (thlen < sizeof(*th)) 3026 goto out; 3027 3028 hlen = off + thlen; 3029 if (skb_gro_header_hard(skb, hlen)) { 3030 th = skb_gro_header_slow(skb, hlen, off); 3031 if (unlikely(!th)) 3032 goto out; 3033 } 3034 3035 skb_gro_pull(skb, thlen); 3036 3037 len = skb_gro_len(skb); 3038 flags = tcp_flag_word(th); 3039 3040 for (; (p = *head); head = &p->next) { 3041 if (!NAPI_GRO_CB(p)->same_flow) 3042 continue; 3043 3044 th2 = tcp_hdr(p); 3045 3046 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) { 3047 NAPI_GRO_CB(p)->same_flow = 0; 3048 continue; 3049 } 3050 3051 goto found; 3052 } 3053 3054 goto out_check_final; 3055 3056 found: 3057 flush = NAPI_GRO_CB(p)->flush; 3058 flush |= (__force int)(flags & TCP_FLAG_CWR); 3059 flush |= (__force int)((flags ^ tcp_flag_word(th2)) & 3060 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); 3061 flush |= (__force int)(th->ack_seq ^ th2->ack_seq); 3062 for (i = sizeof(*th); i < thlen; i += 4) 3063 flush |= *(u32 *)((u8 *)th + i) ^ 3064 *(u32 *)((u8 *)th2 + i); 3065 3066 mss = skb_shinfo(p)->gso_size; 3067 3068 flush |= (len - 1) >= mss; 3069 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); 3070 3071 if (flush || skb_gro_receive(head, skb)) { 3072 mss = 1; 3073 goto out_check_final; 3074 } 3075 3076 p = *head; 3077 th2 = tcp_hdr(p); 3078 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); 3079 3080 out_check_final: 3081 flush = len < mss; 3082 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH | 3083 TCP_FLAG_RST | TCP_FLAG_SYN | 3084 TCP_FLAG_FIN)); 3085 3086 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) 3087 pp = head; 3088 3089 out: 3090 NAPI_GRO_CB(skb)->flush |= flush; 3091 3092 return pp; 3093 } 3094 EXPORT_SYMBOL(tcp_gro_receive); 3095 3096 int tcp_gro_complete(struct sk_buff *skb) 3097 { 3098 struct tcphdr *th = tcp_hdr(skb); 3099 3100 skb->csum_start = skb_transport_header(skb) - skb->head; 3101 skb->csum_offset = offsetof(struct tcphdr, check); 3102 skb->ip_summed = CHECKSUM_PARTIAL; 3103 3104 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 3105 3106 if (th->cwr) 3107 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 3108 3109 return 0; 3110 } 3111 EXPORT_SYMBOL(tcp_gro_complete); 3112 3113 #ifdef CONFIG_TCP_MD5SIG 3114 static unsigned long tcp_md5sig_users; 3115 static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool; 3116 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock); 3117 3118 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool) 3119 { 3120 int cpu; 3121 3122 for_each_possible_cpu(cpu) { 3123 struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu); 3124 3125 if (p->md5_desc.tfm) 3126 crypto_free_hash(p->md5_desc.tfm); 3127 } 3128 free_percpu(pool); 3129 } 3130 3131 void tcp_free_md5sig_pool(void) 3132 { 3133 struct tcp_md5sig_pool __percpu *pool = NULL; 3134 3135 spin_lock_bh(&tcp_md5sig_pool_lock); 3136 if (--tcp_md5sig_users == 0) { 3137 pool = tcp_md5sig_pool; 3138 tcp_md5sig_pool = NULL; 3139 } 3140 spin_unlock_bh(&tcp_md5sig_pool_lock); 3141 if (pool) 3142 __tcp_free_md5sig_pool(pool); 3143 } 3144 EXPORT_SYMBOL(tcp_free_md5sig_pool); 3145 3146 static struct tcp_md5sig_pool __percpu * 3147 __tcp_alloc_md5sig_pool(struct sock *sk) 3148 { 3149 int cpu; 3150 struct tcp_md5sig_pool __percpu *pool; 3151 3152 pool = alloc_percpu(struct tcp_md5sig_pool); 3153 if (!pool) 3154 return NULL; 3155 3156 for_each_possible_cpu(cpu) { 3157 struct crypto_hash *hash; 3158 3159 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 3160 if (!hash || IS_ERR(hash)) 3161 goto out_free; 3162 3163 per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash; 3164 } 3165 return pool; 3166 out_free: 3167 __tcp_free_md5sig_pool(pool); 3168 return NULL; 3169 } 3170 3171 struct tcp_md5sig_pool __percpu *tcp_alloc_md5sig_pool(struct sock *sk) 3172 { 3173 struct tcp_md5sig_pool __percpu *pool; 3174 bool alloc = false; 3175 3176 retry: 3177 spin_lock_bh(&tcp_md5sig_pool_lock); 3178 pool = tcp_md5sig_pool; 3179 if (tcp_md5sig_users++ == 0) { 3180 alloc = true; 3181 spin_unlock_bh(&tcp_md5sig_pool_lock); 3182 } else if (!pool) { 3183 tcp_md5sig_users--; 3184 spin_unlock_bh(&tcp_md5sig_pool_lock); 3185 cpu_relax(); 3186 goto retry; 3187 } else 3188 spin_unlock_bh(&tcp_md5sig_pool_lock); 3189 3190 if (alloc) { 3191 /* we cannot hold spinlock here because this may sleep. */ 3192 struct tcp_md5sig_pool __percpu *p; 3193 3194 p = __tcp_alloc_md5sig_pool(sk); 3195 spin_lock_bh(&tcp_md5sig_pool_lock); 3196 if (!p) { 3197 tcp_md5sig_users--; 3198 spin_unlock_bh(&tcp_md5sig_pool_lock); 3199 return NULL; 3200 } 3201 pool = tcp_md5sig_pool; 3202 if (pool) { 3203 /* oops, it has already been assigned. */ 3204 spin_unlock_bh(&tcp_md5sig_pool_lock); 3205 __tcp_free_md5sig_pool(p); 3206 } else { 3207 tcp_md5sig_pool = pool = p; 3208 spin_unlock_bh(&tcp_md5sig_pool_lock); 3209 } 3210 } 3211 return pool; 3212 } 3213 EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 3214 3215 3216 /** 3217 * tcp_get_md5sig_pool - get md5sig_pool for this user 3218 * 3219 * We use percpu structure, so if we succeed, we exit with preemption 3220 * and BH disabled, to make sure another thread or softirq handling 3221 * wont try to get same context. 3222 */ 3223 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) 3224 { 3225 struct tcp_md5sig_pool __percpu *p; 3226 3227 local_bh_disable(); 3228 3229 spin_lock(&tcp_md5sig_pool_lock); 3230 p = tcp_md5sig_pool; 3231 if (p) 3232 tcp_md5sig_users++; 3233 spin_unlock(&tcp_md5sig_pool_lock); 3234 3235 if (p) 3236 return this_cpu_ptr(p); 3237 3238 local_bh_enable(); 3239 return NULL; 3240 } 3241 EXPORT_SYMBOL(tcp_get_md5sig_pool); 3242 3243 void tcp_put_md5sig_pool(void) 3244 { 3245 local_bh_enable(); 3246 tcp_free_md5sig_pool(); 3247 } 3248 EXPORT_SYMBOL(tcp_put_md5sig_pool); 3249 3250 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp, 3251 const struct tcphdr *th) 3252 { 3253 struct scatterlist sg; 3254 struct tcphdr hdr; 3255 int err; 3256 3257 /* We are not allowed to change tcphdr, make a local copy */ 3258 memcpy(&hdr, th, sizeof(hdr)); 3259 hdr.check = 0; 3260 3261 /* options aren't included in the hash */ 3262 sg_init_one(&sg, &hdr, sizeof(hdr)); 3263 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr)); 3264 return err; 3265 } 3266 EXPORT_SYMBOL(tcp_md5_hash_header); 3267 3268 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, 3269 const struct sk_buff *skb, unsigned int header_len) 3270 { 3271 struct scatterlist sg; 3272 const struct tcphdr *tp = tcp_hdr(skb); 3273 struct hash_desc *desc = &hp->md5_desc; 3274 unsigned int i; 3275 const unsigned int head_data_len = skb_headlen(skb) > header_len ? 3276 skb_headlen(skb) - header_len : 0; 3277 const struct skb_shared_info *shi = skb_shinfo(skb); 3278 struct sk_buff *frag_iter; 3279 3280 sg_init_table(&sg, 1); 3281 3282 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len); 3283 if (crypto_hash_update(desc, &sg, head_data_len)) 3284 return 1; 3285 3286 for (i = 0; i < shi->nr_frags; ++i) { 3287 const struct skb_frag_struct *f = &shi->frags[i]; 3288 struct page *page = skb_frag_page(f); 3289 sg_set_page(&sg, page, skb_frag_size(f), f->page_offset); 3290 if (crypto_hash_update(desc, &sg, skb_frag_size(f))) 3291 return 1; 3292 } 3293 3294 skb_walk_frags(skb, frag_iter) 3295 if (tcp_md5_hash_skb_data(hp, frag_iter, 0)) 3296 return 1; 3297 3298 return 0; 3299 } 3300 EXPORT_SYMBOL(tcp_md5_hash_skb_data); 3301 3302 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key) 3303 { 3304 struct scatterlist sg; 3305 3306 sg_init_one(&sg, key->key, key->keylen); 3307 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen); 3308 } 3309 EXPORT_SYMBOL(tcp_md5_hash_key); 3310 3311 #endif 3312 3313 /** 3314 * Each Responder maintains up to two secret values concurrently for 3315 * efficient secret rollover. Each secret value has 4 states: 3316 * 3317 * Generating. (tcp_secret_generating != tcp_secret_primary) 3318 * Generates new Responder-Cookies, but not yet used for primary 3319 * verification. This is a short-term state, typically lasting only 3320 * one round trip time (RTT). 3321 * 3322 * Primary. (tcp_secret_generating == tcp_secret_primary) 3323 * Used both for generation and primary verification. 3324 * 3325 * Retiring. (tcp_secret_retiring != tcp_secret_secondary) 3326 * Used for verification, until the first failure that can be 3327 * verified by the newer Generating secret. At that time, this 3328 * cookie's state is changed to Secondary, and the Generating 3329 * cookie's state is changed to Primary. This is a short-term state, 3330 * typically lasting only one round trip time (RTT). 3331 * 3332 * Secondary. (tcp_secret_retiring == tcp_secret_secondary) 3333 * Used for secondary verification, after primary verification 3334 * failures. This state lasts no more than twice the Maximum Segment 3335 * Lifetime (2MSL). Then, the secret is discarded. 3336 */ 3337 struct tcp_cookie_secret { 3338 /* The secret is divided into two parts. The digest part is the 3339 * equivalent of previously hashing a secret and saving the state, 3340 * and serves as an initialization vector (IV). The message part 3341 * serves as the trailing secret. 3342 */ 3343 u32 secrets[COOKIE_WORKSPACE_WORDS]; 3344 unsigned long expires; 3345 }; 3346 3347 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL) 3348 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2) 3349 #define TCP_SECRET_LIFE (HZ * 600) 3350 3351 static struct tcp_cookie_secret tcp_secret_one; 3352 static struct tcp_cookie_secret tcp_secret_two; 3353 3354 /* Essentially a circular list, without dynamic allocation. */ 3355 static struct tcp_cookie_secret *tcp_secret_generating; 3356 static struct tcp_cookie_secret *tcp_secret_primary; 3357 static struct tcp_cookie_secret *tcp_secret_retiring; 3358 static struct tcp_cookie_secret *tcp_secret_secondary; 3359 3360 static DEFINE_SPINLOCK(tcp_secret_locker); 3361 3362 /* Select a pseudo-random word in the cookie workspace. 3363 */ 3364 static inline u32 tcp_cookie_work(const u32 *ws, const int n) 3365 { 3366 return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])]; 3367 } 3368 3369 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed. 3370 * Called in softirq context. 3371 * Returns: 0 for success. 3372 */ 3373 int tcp_cookie_generator(u32 *bakery) 3374 { 3375 unsigned long jiffy = jiffies; 3376 3377 if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) { 3378 spin_lock_bh(&tcp_secret_locker); 3379 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) { 3380 /* refreshed by another */ 3381 memcpy(bakery, 3382 &tcp_secret_generating->secrets[0], 3383 COOKIE_WORKSPACE_WORDS); 3384 } else { 3385 /* still needs refreshing */ 3386 get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS); 3387 3388 /* The first time, paranoia assumes that the 3389 * randomization function isn't as strong. But, 3390 * this secret initialization is delayed until 3391 * the last possible moment (packet arrival). 3392 * Although that time is observable, it is 3393 * unpredictably variable. Mash in the most 3394 * volatile clock bits available, and expire the 3395 * secret extra quickly. 3396 */ 3397 if (unlikely(tcp_secret_primary->expires == 3398 tcp_secret_secondary->expires)) { 3399 struct timespec tv; 3400 3401 getnstimeofday(&tv); 3402 bakery[COOKIE_DIGEST_WORDS+0] ^= 3403 (u32)tv.tv_nsec; 3404 3405 tcp_secret_secondary->expires = jiffy 3406 + TCP_SECRET_1MSL 3407 + (0x0f & tcp_cookie_work(bakery, 0)); 3408 } else { 3409 tcp_secret_secondary->expires = jiffy 3410 + TCP_SECRET_LIFE 3411 + (0xff & tcp_cookie_work(bakery, 1)); 3412 tcp_secret_primary->expires = jiffy 3413 + TCP_SECRET_2MSL 3414 + (0x1f & tcp_cookie_work(bakery, 2)); 3415 } 3416 memcpy(&tcp_secret_secondary->secrets[0], 3417 bakery, COOKIE_WORKSPACE_WORDS); 3418 3419 rcu_assign_pointer(tcp_secret_generating, 3420 tcp_secret_secondary); 3421 rcu_assign_pointer(tcp_secret_retiring, 3422 tcp_secret_primary); 3423 /* 3424 * Neither call_rcu() nor synchronize_rcu() needed. 3425 * Retiring data is not freed. It is replaced after 3426 * further (locked) pointer updates, and a quiet time 3427 * (minimum 1MSL, maximum LIFE - 2MSL). 3428 */ 3429 } 3430 spin_unlock_bh(&tcp_secret_locker); 3431 } else { 3432 rcu_read_lock_bh(); 3433 memcpy(bakery, 3434 &rcu_dereference(tcp_secret_generating)->secrets[0], 3435 COOKIE_WORKSPACE_WORDS); 3436 rcu_read_unlock_bh(); 3437 } 3438 return 0; 3439 } 3440 EXPORT_SYMBOL(tcp_cookie_generator); 3441 3442 void tcp_done(struct sock *sk) 3443 { 3444 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 3445 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS); 3446 3447 tcp_set_state(sk, TCP_CLOSE); 3448 tcp_clear_xmit_timers(sk); 3449 3450 sk->sk_shutdown = SHUTDOWN_MASK; 3451 3452 if (!sock_flag(sk, SOCK_DEAD)) 3453 sk->sk_state_change(sk); 3454 else 3455 inet_csk_destroy_sock(sk); 3456 } 3457 EXPORT_SYMBOL_GPL(tcp_done); 3458 3459 extern struct tcp_congestion_ops tcp_reno; 3460 3461 static __initdata unsigned long thash_entries; 3462 static int __init set_thash_entries(char *str) 3463 { 3464 ssize_t ret; 3465 3466 if (!str) 3467 return 0; 3468 3469 ret = kstrtoul(str, 0, &thash_entries); 3470 if (ret) 3471 return 0; 3472 3473 return 1; 3474 } 3475 __setup("thash_entries=", set_thash_entries); 3476 3477 void tcp_init_mem(struct net *net) 3478 { 3479 unsigned long limit = nr_free_buffer_pages() / 8; 3480 limit = max(limit, 128UL); 3481 net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3; 3482 net->ipv4.sysctl_tcp_mem[1] = limit; 3483 net->ipv4.sysctl_tcp_mem[2] = net->ipv4.sysctl_tcp_mem[0] * 2; 3484 } 3485 3486 void __init tcp_init(void) 3487 { 3488 struct sk_buff *skb = NULL; 3489 unsigned long limit; 3490 int max_rshare, max_wshare, cnt; 3491 unsigned int i; 3492 unsigned long jiffy = jiffies; 3493 3494 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb)); 3495 3496 percpu_counter_init(&tcp_sockets_allocated, 0); 3497 percpu_counter_init(&tcp_orphan_count, 0); 3498 tcp_hashinfo.bind_bucket_cachep = 3499 kmem_cache_create("tcp_bind_bucket", 3500 sizeof(struct inet_bind_bucket), 0, 3501 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3502 3503 /* Size and allocate the main established and bind bucket 3504 * hash tables. 3505 * 3506 * The methodology is similar to that of the buffer cache. 3507 */ 3508 tcp_hashinfo.ehash = 3509 alloc_large_system_hash("TCP established", 3510 sizeof(struct inet_ehash_bucket), 3511 thash_entries, 3512 (totalram_pages >= 128 * 1024) ? 3513 13 : 15, 3514 0, 3515 NULL, 3516 &tcp_hashinfo.ehash_mask, 3517 0, 3518 thash_entries ? 0 : 512 * 1024); 3519 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) { 3520 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i); 3521 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i); 3522 } 3523 if (inet_ehash_locks_alloc(&tcp_hashinfo)) 3524 panic("TCP: failed to alloc ehash_locks"); 3525 tcp_hashinfo.bhash = 3526 alloc_large_system_hash("TCP bind", 3527 sizeof(struct inet_bind_hashbucket), 3528 tcp_hashinfo.ehash_mask + 1, 3529 (totalram_pages >= 128 * 1024) ? 3530 13 : 15, 3531 0, 3532 &tcp_hashinfo.bhash_size, 3533 NULL, 3534 0, 3535 64 * 1024); 3536 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size; 3537 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 3538 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 3539 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 3540 } 3541 3542 3543 cnt = tcp_hashinfo.ehash_mask + 1; 3544 3545 tcp_death_row.sysctl_max_tw_buckets = cnt / 2; 3546 sysctl_tcp_max_orphans = cnt / 2; 3547 sysctl_max_syn_backlog = max(128, cnt / 256); 3548 3549 tcp_init_mem(&init_net); 3550 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 3551 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7); 3552 max_wshare = min(4UL*1024*1024, limit); 3553 max_rshare = min(6UL*1024*1024, limit); 3554 3555 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM; 3556 sysctl_tcp_wmem[1] = 16*1024; 3557 sysctl_tcp_wmem[2] = max(64*1024, max_wshare); 3558 3559 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; 3560 sysctl_tcp_rmem[1] = 87380; 3561 sysctl_tcp_rmem[2] = max(87380, max_rshare); 3562 3563 pr_info("Hash tables configured (established %u bind %u)\n", 3564 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size); 3565 3566 tcp_register_congestion_control(&tcp_reno); 3567 3568 memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets)); 3569 memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets)); 3570 tcp_secret_one.expires = jiffy; /* past due */ 3571 tcp_secret_two.expires = jiffy; /* past due */ 3572 tcp_secret_generating = &tcp_secret_one; 3573 tcp_secret_primary = &tcp_secret_one; 3574 tcp_secret_retiring = &tcp_secret_two; 3575 tcp_secret_secondary = &tcp_secret_two; 3576 } 3577