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/inet_common.h> 274 #include <net/tcp.h> 275 #include <net/xfrm.h> 276 #include <net/ip.h> 277 #include <net/netdma.h> 278 #include <net/sock.h> 279 280 #include <asm/uaccess.h> 281 #include <asm/ioctls.h> 282 283 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT; 284 285 struct percpu_counter tcp_orphan_count; 286 EXPORT_SYMBOL_GPL(tcp_orphan_count); 287 288 int sysctl_tcp_wmem[3] __read_mostly; 289 int sysctl_tcp_rmem[3] __read_mostly; 290 291 EXPORT_SYMBOL(sysctl_tcp_rmem); 292 EXPORT_SYMBOL(sysctl_tcp_wmem); 293 294 atomic_long_t tcp_memory_allocated; /* Current allocated memory. */ 295 EXPORT_SYMBOL(tcp_memory_allocated); 296 297 /* 298 * Current number of TCP sockets. 299 */ 300 struct percpu_counter tcp_sockets_allocated; 301 EXPORT_SYMBOL(tcp_sockets_allocated); 302 303 /* 304 * TCP splice context 305 */ 306 struct tcp_splice_state { 307 struct pipe_inode_info *pipe; 308 size_t len; 309 unsigned int flags; 310 }; 311 312 /* 313 * Pressure flag: try to collapse. 314 * Technical note: it is used by multiple contexts non atomically. 315 * All the __sk_mem_schedule() is of this nature: accounting 316 * is strict, actions are advisory and have some latency. 317 */ 318 int tcp_memory_pressure __read_mostly; 319 EXPORT_SYMBOL(tcp_memory_pressure); 320 321 void tcp_enter_memory_pressure(struct sock *sk) 322 { 323 if (!tcp_memory_pressure) { 324 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES); 325 tcp_memory_pressure = 1; 326 } 327 } 328 EXPORT_SYMBOL(tcp_enter_memory_pressure); 329 330 /* Convert seconds to retransmits based on initial and max timeout */ 331 static u8 secs_to_retrans(int seconds, int timeout, int rto_max) 332 { 333 u8 res = 0; 334 335 if (seconds > 0) { 336 int period = timeout; 337 338 res = 1; 339 while (seconds > period && res < 255) { 340 res++; 341 timeout <<= 1; 342 if (timeout > rto_max) 343 timeout = rto_max; 344 period += timeout; 345 } 346 } 347 return res; 348 } 349 350 /* Convert retransmits to seconds based on initial and max timeout */ 351 static int retrans_to_secs(u8 retrans, int timeout, int rto_max) 352 { 353 int period = 0; 354 355 if (retrans > 0) { 356 period = timeout; 357 while (--retrans) { 358 timeout <<= 1; 359 if (timeout > rto_max) 360 timeout = rto_max; 361 period += timeout; 362 } 363 } 364 return period; 365 } 366 367 /* Address-family independent initialization for a tcp_sock. 368 * 369 * NOTE: A lot of things set to zero explicitly by call to 370 * sk_alloc() so need not be done here. 371 */ 372 void tcp_init_sock(struct sock *sk) 373 { 374 struct inet_connection_sock *icsk = inet_csk(sk); 375 struct tcp_sock *tp = tcp_sk(sk); 376 377 skb_queue_head_init(&tp->out_of_order_queue); 378 tcp_init_xmit_timers(sk); 379 tcp_prequeue_init(tp); 380 INIT_LIST_HEAD(&tp->tsq_node); 381 382 icsk->icsk_rto = TCP_TIMEOUT_INIT; 383 tp->mdev = TCP_TIMEOUT_INIT; 384 385 /* So many TCP implementations out there (incorrectly) count the 386 * initial SYN frame in their delayed-ACK and congestion control 387 * algorithms that we must have the following bandaid to talk 388 * efficiently to them. -DaveM 389 */ 390 tp->snd_cwnd = TCP_INIT_CWND; 391 392 /* See draft-stevens-tcpca-spec-01 for discussion of the 393 * initialization of these values. 394 */ 395 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 396 tp->snd_cwnd_clamp = ~0; 397 tp->mss_cache = TCP_MSS_DEFAULT; 398 399 tp->reordering = sysctl_tcp_reordering; 400 tcp_enable_early_retrans(tp); 401 icsk->icsk_ca_ops = &tcp_init_congestion_ops; 402 403 sk->sk_state = TCP_CLOSE; 404 405 sk->sk_write_space = sk_stream_write_space; 406 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 407 408 icsk->icsk_sync_mss = tcp_sync_mss; 409 410 /* TCP Cookie Transactions */ 411 if (sysctl_tcp_cookie_size > 0) { 412 /* Default, cookies without s_data_payload. */ 413 tp->cookie_values = 414 kzalloc(sizeof(*tp->cookie_values), 415 sk->sk_allocation); 416 if (tp->cookie_values != NULL) 417 kref_init(&tp->cookie_values->kref); 418 } 419 /* Presumed zeroed, in order of appearance: 420 * cookie_in_always, cookie_out_never, 421 * s_data_constant, s_data_in, s_data_out 422 */ 423 sk->sk_sndbuf = sysctl_tcp_wmem[1]; 424 sk->sk_rcvbuf = sysctl_tcp_rmem[1]; 425 426 local_bh_disable(); 427 sock_update_memcg(sk); 428 sk_sockets_allocated_inc(sk); 429 local_bh_enable(); 430 } 431 EXPORT_SYMBOL(tcp_init_sock); 432 433 /* 434 * Wait for a TCP event. 435 * 436 * Note that we don't need to lock the socket, as the upper poll layers 437 * take care of normal races (between the test and the event) and we don't 438 * go look at any of the socket buffers directly. 439 */ 440 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) 441 { 442 unsigned int mask; 443 struct sock *sk = sock->sk; 444 const struct tcp_sock *tp = tcp_sk(sk); 445 446 sock_poll_wait(file, sk_sleep(sk), wait); 447 if (sk->sk_state == TCP_LISTEN) 448 return inet_csk_listen_poll(sk); 449 450 /* Socket is not locked. We are protected from async events 451 * by poll logic and correct handling of state changes 452 * made by other threads is impossible in any case. 453 */ 454 455 mask = 0; 456 457 /* 458 * POLLHUP is certainly not done right. But poll() doesn't 459 * have a notion of HUP in just one direction, and for a 460 * socket the read side is more interesting. 461 * 462 * Some poll() documentation says that POLLHUP is incompatible 463 * with the POLLOUT/POLLWR flags, so somebody should check this 464 * all. But careful, it tends to be safer to return too many 465 * bits than too few, and you can easily break real applications 466 * if you don't tell them that something has hung up! 467 * 468 * Check-me. 469 * 470 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and 471 * our fs/select.c). It means that after we received EOF, 472 * poll always returns immediately, making impossible poll() on write() 473 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP 474 * if and only if shutdown has been made in both directions. 475 * Actually, it is interesting to look how Solaris and DUX 476 * solve this dilemma. I would prefer, if POLLHUP were maskable, 477 * then we could set it on SND_SHUTDOWN. BTW examples given 478 * in Stevens' books assume exactly this behaviour, it explains 479 * why POLLHUP is incompatible with POLLOUT. --ANK 480 * 481 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent 482 * blocking on fresh not-connected or disconnected socket. --ANK 483 */ 484 if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) 485 mask |= POLLHUP; 486 if (sk->sk_shutdown & RCV_SHUTDOWN) 487 mask |= POLLIN | POLLRDNORM | POLLRDHUP; 488 489 /* Connected or passive Fast Open socket? */ 490 if (sk->sk_state != TCP_SYN_SENT && 491 (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk != NULL)) { 492 int target = sock_rcvlowat(sk, 0, INT_MAX); 493 494 if (tp->urg_seq == tp->copied_seq && 495 !sock_flag(sk, SOCK_URGINLINE) && 496 tp->urg_data) 497 target++; 498 499 /* Potential race condition. If read of tp below will 500 * escape above sk->sk_state, we can be illegally awaken 501 * in SYN_* states. */ 502 if (tp->rcv_nxt - tp->copied_seq >= target) 503 mask |= POLLIN | POLLRDNORM; 504 505 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { 506 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) { 507 mask |= POLLOUT | POLLWRNORM; 508 } else { /* send SIGIO later */ 509 set_bit(SOCK_ASYNC_NOSPACE, 510 &sk->sk_socket->flags); 511 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 512 513 /* Race breaker. If space is freed after 514 * wspace test but before the flags are set, 515 * IO signal will be lost. 516 */ 517 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) 518 mask |= POLLOUT | POLLWRNORM; 519 } 520 } else 521 mask |= POLLOUT | POLLWRNORM; 522 523 if (tp->urg_data & TCP_URG_VALID) 524 mask |= POLLPRI; 525 } 526 /* This barrier is coupled with smp_wmb() in tcp_reset() */ 527 smp_rmb(); 528 if (sk->sk_err) 529 mask |= POLLERR; 530 531 return mask; 532 } 533 EXPORT_SYMBOL(tcp_poll); 534 535 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 536 { 537 struct tcp_sock *tp = tcp_sk(sk); 538 int answ; 539 540 switch (cmd) { 541 case SIOCINQ: 542 if (sk->sk_state == TCP_LISTEN) 543 return -EINVAL; 544 545 lock_sock(sk); 546 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 547 answ = 0; 548 else if (sock_flag(sk, SOCK_URGINLINE) || 549 !tp->urg_data || 550 before(tp->urg_seq, tp->copied_seq) || 551 !before(tp->urg_seq, tp->rcv_nxt)) { 552 553 answ = tp->rcv_nxt - tp->copied_seq; 554 555 /* Subtract 1, if FIN was received */ 556 if (answ && sock_flag(sk, SOCK_DONE)) 557 answ--; 558 } else 559 answ = tp->urg_seq - tp->copied_seq; 560 release_sock(sk); 561 break; 562 case SIOCATMARK: 563 answ = tp->urg_data && tp->urg_seq == tp->copied_seq; 564 break; 565 case SIOCOUTQ: 566 if (sk->sk_state == TCP_LISTEN) 567 return -EINVAL; 568 569 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 570 answ = 0; 571 else 572 answ = tp->write_seq - tp->snd_una; 573 break; 574 case SIOCOUTQNSD: 575 if (sk->sk_state == TCP_LISTEN) 576 return -EINVAL; 577 578 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 579 answ = 0; 580 else 581 answ = tp->write_seq - tp->snd_nxt; 582 break; 583 default: 584 return -ENOIOCTLCMD; 585 } 586 587 return put_user(answ, (int __user *)arg); 588 } 589 EXPORT_SYMBOL(tcp_ioctl); 590 591 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb) 592 { 593 TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH; 594 tp->pushed_seq = tp->write_seq; 595 } 596 597 static inline bool forced_push(const struct tcp_sock *tp) 598 { 599 return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1)); 600 } 601 602 static inline void skb_entail(struct sock *sk, struct sk_buff *skb) 603 { 604 struct tcp_sock *tp = tcp_sk(sk); 605 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 606 607 skb->csum = 0; 608 tcb->seq = tcb->end_seq = tp->write_seq; 609 tcb->tcp_flags = TCPHDR_ACK; 610 tcb->sacked = 0; 611 skb_header_release(skb); 612 tcp_add_write_queue_tail(sk, skb); 613 sk->sk_wmem_queued += skb->truesize; 614 sk_mem_charge(sk, skb->truesize); 615 if (tp->nonagle & TCP_NAGLE_PUSH) 616 tp->nonagle &= ~TCP_NAGLE_PUSH; 617 } 618 619 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags) 620 { 621 if (flags & MSG_OOB) 622 tp->snd_up = tp->write_seq; 623 } 624 625 static inline void tcp_push(struct sock *sk, int flags, int mss_now, 626 int nonagle) 627 { 628 if (tcp_send_head(sk)) { 629 struct tcp_sock *tp = tcp_sk(sk); 630 631 if (!(flags & MSG_MORE) || forced_push(tp)) 632 tcp_mark_push(tp, tcp_write_queue_tail(sk)); 633 634 tcp_mark_urg(tp, flags); 635 __tcp_push_pending_frames(sk, mss_now, 636 (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle); 637 } 638 } 639 640 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, 641 unsigned int offset, size_t len) 642 { 643 struct tcp_splice_state *tss = rd_desc->arg.data; 644 int ret; 645 646 ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len), 647 tss->flags); 648 if (ret > 0) 649 rd_desc->count -= ret; 650 return ret; 651 } 652 653 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss) 654 { 655 /* Store TCP splice context information in read_descriptor_t. */ 656 read_descriptor_t rd_desc = { 657 .arg.data = tss, 658 .count = tss->len, 659 }; 660 661 return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv); 662 } 663 664 /** 665 * tcp_splice_read - splice data from TCP socket to a pipe 666 * @sock: socket to splice from 667 * @ppos: position (not valid) 668 * @pipe: pipe to splice to 669 * @len: number of bytes to splice 670 * @flags: splice modifier flags 671 * 672 * Description: 673 * Will read pages from given socket and fill them into a pipe. 674 * 675 **/ 676 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, 677 struct pipe_inode_info *pipe, size_t len, 678 unsigned int flags) 679 { 680 struct sock *sk = sock->sk; 681 struct tcp_splice_state tss = { 682 .pipe = pipe, 683 .len = len, 684 .flags = flags, 685 }; 686 long timeo; 687 ssize_t spliced; 688 int ret; 689 690 sock_rps_record_flow(sk); 691 /* 692 * We can't seek on a socket input 693 */ 694 if (unlikely(*ppos)) 695 return -ESPIPE; 696 697 ret = spliced = 0; 698 699 lock_sock(sk); 700 701 timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK); 702 while (tss.len) { 703 ret = __tcp_splice_read(sk, &tss); 704 if (ret < 0) 705 break; 706 else if (!ret) { 707 if (spliced) 708 break; 709 if (sock_flag(sk, SOCK_DONE)) 710 break; 711 if (sk->sk_err) { 712 ret = sock_error(sk); 713 break; 714 } 715 if (sk->sk_shutdown & RCV_SHUTDOWN) 716 break; 717 if (sk->sk_state == TCP_CLOSE) { 718 /* 719 * This occurs when user tries to read 720 * from never connected socket. 721 */ 722 if (!sock_flag(sk, SOCK_DONE)) 723 ret = -ENOTCONN; 724 break; 725 } 726 if (!timeo) { 727 ret = -EAGAIN; 728 break; 729 } 730 sk_wait_data(sk, &timeo); 731 if (signal_pending(current)) { 732 ret = sock_intr_errno(timeo); 733 break; 734 } 735 continue; 736 } 737 tss.len -= ret; 738 spliced += ret; 739 740 if (!timeo) 741 break; 742 release_sock(sk); 743 lock_sock(sk); 744 745 if (sk->sk_err || sk->sk_state == TCP_CLOSE || 746 (sk->sk_shutdown & RCV_SHUTDOWN) || 747 signal_pending(current)) 748 break; 749 } 750 751 release_sock(sk); 752 753 if (spliced) 754 return spliced; 755 756 return ret; 757 } 758 EXPORT_SYMBOL(tcp_splice_read); 759 760 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp) 761 { 762 struct sk_buff *skb; 763 764 /* The TCP header must be at least 32-bit aligned. */ 765 size = ALIGN(size, 4); 766 767 skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); 768 if (skb) { 769 if (sk_wmem_schedule(sk, skb->truesize)) { 770 skb_reserve(skb, sk->sk_prot->max_header); 771 /* 772 * Make sure that we have exactly size bytes 773 * available to the caller, no more, no less. 774 */ 775 skb->avail_size = size; 776 return skb; 777 } 778 __kfree_skb(skb); 779 } else { 780 sk->sk_prot->enter_memory_pressure(sk); 781 sk_stream_moderate_sndbuf(sk); 782 } 783 return NULL; 784 } 785 786 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now, 787 int large_allowed) 788 { 789 struct tcp_sock *tp = tcp_sk(sk); 790 u32 xmit_size_goal, old_size_goal; 791 792 xmit_size_goal = mss_now; 793 794 if (large_allowed && sk_can_gso(sk)) { 795 xmit_size_goal = ((sk->sk_gso_max_size - 1) - 796 inet_csk(sk)->icsk_af_ops->net_header_len - 797 inet_csk(sk)->icsk_ext_hdr_len - 798 tp->tcp_header_len); 799 800 /* TSQ : try to have two TSO segments in flight */ 801 xmit_size_goal = min_t(u32, xmit_size_goal, 802 sysctl_tcp_limit_output_bytes >> 1); 803 804 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal); 805 806 /* We try hard to avoid divides here */ 807 old_size_goal = tp->xmit_size_goal_segs * mss_now; 808 809 if (likely(old_size_goal <= xmit_size_goal && 810 old_size_goal + mss_now > xmit_size_goal)) { 811 xmit_size_goal = old_size_goal; 812 } else { 813 tp->xmit_size_goal_segs = 814 min_t(u16, xmit_size_goal / mss_now, 815 sk->sk_gso_max_segs); 816 xmit_size_goal = tp->xmit_size_goal_segs * mss_now; 817 } 818 } 819 820 return max(xmit_size_goal, mss_now); 821 } 822 823 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags) 824 { 825 int mss_now; 826 827 mss_now = tcp_current_mss(sk); 828 *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB)); 829 830 return mss_now; 831 } 832 833 static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, 834 size_t size, int flags) 835 { 836 struct tcp_sock *tp = tcp_sk(sk); 837 int mss_now, size_goal; 838 int err; 839 ssize_t copied; 840 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 841 842 /* Wait for a connection to finish. One exception is TCP Fast Open 843 * (passive side) where data is allowed to be sent before a connection 844 * is fully established. 845 */ 846 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) && 847 !tcp_passive_fastopen(sk)) { 848 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 849 goto out_err; 850 } 851 852 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 853 854 mss_now = tcp_send_mss(sk, &size_goal, flags); 855 copied = 0; 856 857 err = -EPIPE; 858 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 859 goto out_err; 860 861 while (size > 0) { 862 struct sk_buff *skb = tcp_write_queue_tail(sk); 863 int copy, i; 864 bool can_coalesce; 865 866 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) { 867 new_segment: 868 if (!sk_stream_memory_free(sk)) 869 goto wait_for_sndbuf; 870 871 skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation); 872 if (!skb) 873 goto wait_for_memory; 874 875 skb_entail(sk, skb); 876 copy = size_goal; 877 } 878 879 if (copy > size) 880 copy = size; 881 882 i = skb_shinfo(skb)->nr_frags; 883 can_coalesce = skb_can_coalesce(skb, i, page, offset); 884 if (!can_coalesce && i >= MAX_SKB_FRAGS) { 885 tcp_mark_push(tp, skb); 886 goto new_segment; 887 } 888 if (!sk_wmem_schedule(sk, copy)) 889 goto wait_for_memory; 890 891 if (can_coalesce) { 892 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 893 } else { 894 get_page(page); 895 skb_fill_page_desc(skb, i, page, offset, copy); 896 } 897 898 skb->len += copy; 899 skb->data_len += copy; 900 skb->truesize += copy; 901 sk->sk_wmem_queued += copy; 902 sk_mem_charge(sk, copy); 903 skb->ip_summed = CHECKSUM_PARTIAL; 904 tp->write_seq += copy; 905 TCP_SKB_CB(skb)->end_seq += copy; 906 skb_shinfo(skb)->gso_segs = 0; 907 908 if (!copied) 909 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 910 911 copied += copy; 912 offset += copy; 913 if (!(size -= copy)) 914 goto out; 915 916 if (skb->len < size_goal || (flags & MSG_OOB)) 917 continue; 918 919 if (forced_push(tp)) { 920 tcp_mark_push(tp, skb); 921 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 922 } else if (skb == tcp_send_head(sk)) 923 tcp_push_one(sk, mss_now); 924 continue; 925 926 wait_for_sndbuf: 927 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 928 wait_for_memory: 929 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 930 931 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 932 goto do_error; 933 934 mss_now = tcp_send_mss(sk, &size_goal, flags); 935 } 936 937 out: 938 if (copied && !(flags & MSG_SENDPAGE_NOTLAST)) 939 tcp_push(sk, flags, mss_now, tp->nonagle); 940 return copied; 941 942 do_error: 943 if (copied) 944 goto out; 945 out_err: 946 return sk_stream_error(sk, flags, err); 947 } 948 949 int tcp_sendpage(struct sock *sk, struct page *page, int offset, 950 size_t size, int flags) 951 { 952 ssize_t res; 953 954 if (!(sk->sk_route_caps & NETIF_F_SG) || 955 !(sk->sk_route_caps & NETIF_F_ALL_CSUM)) 956 return sock_no_sendpage(sk->sk_socket, page, offset, size, 957 flags); 958 959 lock_sock(sk); 960 res = do_tcp_sendpages(sk, page, offset, size, flags); 961 release_sock(sk); 962 return res; 963 } 964 EXPORT_SYMBOL(tcp_sendpage); 965 966 static inline int select_size(const struct sock *sk, bool sg) 967 { 968 const struct tcp_sock *tp = tcp_sk(sk); 969 int tmp = tp->mss_cache; 970 971 if (sg) { 972 if (sk_can_gso(sk)) { 973 /* Small frames wont use a full page: 974 * Payload will immediately follow tcp header. 975 */ 976 tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER); 977 } else { 978 int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER); 979 980 if (tmp >= pgbreak && 981 tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE) 982 tmp = pgbreak; 983 } 984 } 985 986 return tmp; 987 } 988 989 void tcp_free_fastopen_req(struct tcp_sock *tp) 990 { 991 if (tp->fastopen_req != NULL) { 992 kfree(tp->fastopen_req); 993 tp->fastopen_req = NULL; 994 } 995 } 996 997 static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *size) 998 { 999 struct tcp_sock *tp = tcp_sk(sk); 1000 int err, flags; 1001 1002 if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE)) 1003 return -EOPNOTSUPP; 1004 if (tp->fastopen_req != NULL) 1005 return -EALREADY; /* Another Fast Open is in progress */ 1006 1007 tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request), 1008 sk->sk_allocation); 1009 if (unlikely(tp->fastopen_req == NULL)) 1010 return -ENOBUFS; 1011 tp->fastopen_req->data = msg; 1012 1013 flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0; 1014 err = __inet_stream_connect(sk->sk_socket, msg->msg_name, 1015 msg->msg_namelen, flags); 1016 *size = tp->fastopen_req->copied; 1017 tcp_free_fastopen_req(tp); 1018 return err; 1019 } 1020 1021 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 1022 size_t size) 1023 { 1024 struct iovec *iov; 1025 struct tcp_sock *tp = tcp_sk(sk); 1026 struct sk_buff *skb; 1027 int iovlen, flags, err, copied = 0; 1028 int mss_now = 0, size_goal, copied_syn = 0, offset = 0; 1029 bool sg; 1030 long timeo; 1031 1032 lock_sock(sk); 1033 1034 flags = msg->msg_flags; 1035 if (flags & MSG_FASTOPEN) { 1036 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn); 1037 if (err == -EINPROGRESS && copied_syn > 0) 1038 goto out; 1039 else if (err) 1040 goto out_err; 1041 offset = copied_syn; 1042 } 1043 1044 timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 1045 1046 /* Wait for a connection to finish. One exception is TCP Fast Open 1047 * (passive side) where data is allowed to be sent before a connection 1048 * is fully established. 1049 */ 1050 if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) && 1051 !tcp_passive_fastopen(sk)) { 1052 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) 1053 goto do_error; 1054 } 1055 1056 if (unlikely(tp->repair)) { 1057 if (tp->repair_queue == TCP_RECV_QUEUE) { 1058 copied = tcp_send_rcvq(sk, msg, size); 1059 goto out; 1060 } 1061 1062 err = -EINVAL; 1063 if (tp->repair_queue == TCP_NO_QUEUE) 1064 goto out_err; 1065 1066 /* 'common' sending to sendq */ 1067 } 1068 1069 /* This should be in poll */ 1070 clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 1071 1072 mss_now = tcp_send_mss(sk, &size_goal, flags); 1073 1074 /* Ok commence sending. */ 1075 iovlen = msg->msg_iovlen; 1076 iov = msg->msg_iov; 1077 copied = 0; 1078 1079 err = -EPIPE; 1080 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) 1081 goto out_err; 1082 1083 sg = !!(sk->sk_route_caps & NETIF_F_SG); 1084 1085 while (--iovlen >= 0) { 1086 size_t seglen = iov->iov_len; 1087 unsigned char __user *from = iov->iov_base; 1088 1089 iov++; 1090 if (unlikely(offset > 0)) { /* Skip bytes copied in SYN */ 1091 if (offset >= seglen) { 1092 offset -= seglen; 1093 continue; 1094 } 1095 seglen -= offset; 1096 from += offset; 1097 offset = 0; 1098 } 1099 1100 while (seglen > 0) { 1101 int copy = 0; 1102 int max = size_goal; 1103 1104 skb = tcp_write_queue_tail(sk); 1105 if (tcp_send_head(sk)) { 1106 if (skb->ip_summed == CHECKSUM_NONE) 1107 max = mss_now; 1108 copy = max - skb->len; 1109 } 1110 1111 if (copy <= 0) { 1112 new_segment: 1113 /* Allocate new segment. If the interface is SG, 1114 * allocate skb fitting to single page. 1115 */ 1116 if (!sk_stream_memory_free(sk)) 1117 goto wait_for_sndbuf; 1118 1119 skb = sk_stream_alloc_skb(sk, 1120 select_size(sk, sg), 1121 sk->sk_allocation); 1122 if (!skb) 1123 goto wait_for_memory; 1124 1125 /* 1126 * Check whether we can use HW checksum. 1127 */ 1128 if (sk->sk_route_caps & NETIF_F_ALL_CSUM) 1129 skb->ip_summed = CHECKSUM_PARTIAL; 1130 1131 skb_entail(sk, skb); 1132 copy = size_goal; 1133 max = size_goal; 1134 } 1135 1136 /* Try to append data to the end of skb. */ 1137 if (copy > seglen) 1138 copy = seglen; 1139 1140 /* Where to copy to? */ 1141 if (skb_availroom(skb) > 0) { 1142 /* We have some space in skb head. Superb! */ 1143 copy = min_t(int, copy, skb_availroom(skb)); 1144 err = skb_add_data_nocache(sk, skb, from, copy); 1145 if (err) 1146 goto do_fault; 1147 } else { 1148 bool merge = true; 1149 int i = skb_shinfo(skb)->nr_frags; 1150 struct page_frag *pfrag = sk_page_frag(sk); 1151 1152 if (!sk_page_frag_refill(sk, pfrag)) 1153 goto wait_for_memory; 1154 1155 if (!skb_can_coalesce(skb, i, pfrag->page, 1156 pfrag->offset)) { 1157 if (i == MAX_SKB_FRAGS || !sg) { 1158 tcp_mark_push(tp, skb); 1159 goto new_segment; 1160 } 1161 merge = false; 1162 } 1163 1164 copy = min_t(int, copy, pfrag->size - pfrag->offset); 1165 1166 if (!sk_wmem_schedule(sk, copy)) 1167 goto wait_for_memory; 1168 1169 err = skb_copy_to_page_nocache(sk, from, skb, 1170 pfrag->page, 1171 pfrag->offset, 1172 copy); 1173 if (err) 1174 goto do_error; 1175 1176 /* Update the skb. */ 1177 if (merge) { 1178 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1179 } else { 1180 skb_fill_page_desc(skb, i, pfrag->page, 1181 pfrag->offset, copy); 1182 get_page(pfrag->page); 1183 } 1184 pfrag->offset += copy; 1185 } 1186 1187 if (!copied) 1188 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 1189 1190 tp->write_seq += copy; 1191 TCP_SKB_CB(skb)->end_seq += copy; 1192 skb_shinfo(skb)->gso_segs = 0; 1193 1194 from += copy; 1195 copied += copy; 1196 if ((seglen -= copy) == 0 && iovlen == 0) 1197 goto out; 1198 1199 if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair)) 1200 continue; 1201 1202 if (forced_push(tp)) { 1203 tcp_mark_push(tp, skb); 1204 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); 1205 } else if (skb == tcp_send_head(sk)) 1206 tcp_push_one(sk, mss_now); 1207 continue; 1208 1209 wait_for_sndbuf: 1210 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1211 wait_for_memory: 1212 if (copied) 1213 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH); 1214 1215 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) 1216 goto do_error; 1217 1218 mss_now = tcp_send_mss(sk, &size_goal, flags); 1219 } 1220 } 1221 1222 out: 1223 if (copied) 1224 tcp_push(sk, flags, mss_now, tp->nonagle); 1225 release_sock(sk); 1226 return copied + copied_syn; 1227 1228 do_fault: 1229 if (!skb->len) { 1230 tcp_unlink_write_queue(skb, sk); 1231 /* It is the one place in all of TCP, except connection 1232 * reset, where we can be unlinking the send_head. 1233 */ 1234 tcp_check_send_head(sk, skb); 1235 sk_wmem_free_skb(sk, skb); 1236 } 1237 1238 do_error: 1239 if (copied + copied_syn) 1240 goto out; 1241 out_err: 1242 err = sk_stream_error(sk, flags, err); 1243 release_sock(sk); 1244 return err; 1245 } 1246 EXPORT_SYMBOL(tcp_sendmsg); 1247 1248 /* 1249 * Handle reading urgent data. BSD has very simple semantics for 1250 * this, no blocking and very strange errors 8) 1251 */ 1252 1253 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags) 1254 { 1255 struct tcp_sock *tp = tcp_sk(sk); 1256 1257 /* No URG data to read. */ 1258 if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data || 1259 tp->urg_data == TCP_URG_READ) 1260 return -EINVAL; /* Yes this is right ! */ 1261 1262 if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE)) 1263 return -ENOTCONN; 1264 1265 if (tp->urg_data & TCP_URG_VALID) { 1266 int err = 0; 1267 char c = tp->urg_data; 1268 1269 if (!(flags & MSG_PEEK)) 1270 tp->urg_data = TCP_URG_READ; 1271 1272 /* Read urgent data. */ 1273 msg->msg_flags |= MSG_OOB; 1274 1275 if (len > 0) { 1276 if (!(flags & MSG_TRUNC)) 1277 err = memcpy_toiovec(msg->msg_iov, &c, 1); 1278 len = 1; 1279 } else 1280 msg->msg_flags |= MSG_TRUNC; 1281 1282 return err ? -EFAULT : len; 1283 } 1284 1285 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 1286 return 0; 1287 1288 /* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and 1289 * the available implementations agree in this case: 1290 * this call should never block, independent of the 1291 * blocking state of the socket. 1292 * Mike <pall@rz.uni-karlsruhe.de> 1293 */ 1294 return -EAGAIN; 1295 } 1296 1297 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len) 1298 { 1299 struct sk_buff *skb; 1300 int copied = 0, err = 0; 1301 1302 /* XXX -- need to support SO_PEEK_OFF */ 1303 1304 skb_queue_walk(&sk->sk_write_queue, skb) { 1305 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len); 1306 if (err) 1307 break; 1308 1309 copied += skb->len; 1310 } 1311 1312 return err ?: copied; 1313 } 1314 1315 /* Clean up the receive buffer for full frames taken by the user, 1316 * then send an ACK if necessary. COPIED is the number of bytes 1317 * tcp_recvmsg has given to the user so far, it speeds up the 1318 * calculation of whether or not we must ACK for the sake of 1319 * a window update. 1320 */ 1321 void tcp_cleanup_rbuf(struct sock *sk, int copied) 1322 { 1323 struct tcp_sock *tp = tcp_sk(sk); 1324 bool time_to_ack = false; 1325 1326 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); 1327 1328 WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq), 1329 "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n", 1330 tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt); 1331 1332 if (inet_csk_ack_scheduled(sk)) { 1333 const struct inet_connection_sock *icsk = inet_csk(sk); 1334 /* Delayed ACKs frequently hit locked sockets during bulk 1335 * receive. */ 1336 if (icsk->icsk_ack.blocked || 1337 /* Once-per-two-segments ACK was not sent by tcp_input.c */ 1338 tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss || 1339 /* 1340 * If this read emptied read buffer, we send ACK, if 1341 * connection is not bidirectional, user drained 1342 * receive buffer and there was a small segment 1343 * in queue. 1344 */ 1345 (copied > 0 && 1346 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) || 1347 ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) && 1348 !icsk->icsk_ack.pingpong)) && 1349 !atomic_read(&sk->sk_rmem_alloc))) 1350 time_to_ack = true; 1351 } 1352 1353 /* We send an ACK if we can now advertise a non-zero window 1354 * which has been raised "significantly". 1355 * 1356 * Even if window raised up to infinity, do not send window open ACK 1357 * in states, where we will not receive more. It is useless. 1358 */ 1359 if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 1360 __u32 rcv_window_now = tcp_receive_window(tp); 1361 1362 /* Optimize, __tcp_select_window() is not cheap. */ 1363 if (2*rcv_window_now <= tp->window_clamp) { 1364 __u32 new_window = __tcp_select_window(sk); 1365 1366 /* Send ACK now, if this read freed lots of space 1367 * in our buffer. Certainly, new_window is new window. 1368 * We can advertise it now, if it is not less than current one. 1369 * "Lots" means "at least twice" here. 1370 */ 1371 if (new_window && new_window >= 2 * rcv_window_now) 1372 time_to_ack = true; 1373 } 1374 } 1375 if (time_to_ack) 1376 tcp_send_ack(sk); 1377 } 1378 1379 static void tcp_prequeue_process(struct sock *sk) 1380 { 1381 struct sk_buff *skb; 1382 struct tcp_sock *tp = tcp_sk(sk); 1383 1384 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED); 1385 1386 /* RX process wants to run with disabled BHs, though it is not 1387 * necessary */ 1388 local_bh_disable(); 1389 while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) 1390 sk_backlog_rcv(sk, skb); 1391 local_bh_enable(); 1392 1393 /* Clear memory counter. */ 1394 tp->ucopy.memory = 0; 1395 } 1396 1397 #ifdef CONFIG_NET_DMA 1398 static void tcp_service_net_dma(struct sock *sk, bool wait) 1399 { 1400 dma_cookie_t done, used; 1401 dma_cookie_t last_issued; 1402 struct tcp_sock *tp = tcp_sk(sk); 1403 1404 if (!tp->ucopy.dma_chan) 1405 return; 1406 1407 last_issued = tp->ucopy.dma_cookie; 1408 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1409 1410 do { 1411 if (dma_async_memcpy_complete(tp->ucopy.dma_chan, 1412 last_issued, &done, 1413 &used) == DMA_SUCCESS) { 1414 /* Safe to free early-copied skbs now */ 1415 __skb_queue_purge(&sk->sk_async_wait_queue); 1416 break; 1417 } else { 1418 struct sk_buff *skb; 1419 while ((skb = skb_peek(&sk->sk_async_wait_queue)) && 1420 (dma_async_is_complete(skb->dma_cookie, done, 1421 used) == DMA_SUCCESS)) { 1422 __skb_dequeue(&sk->sk_async_wait_queue); 1423 kfree_skb(skb); 1424 } 1425 } 1426 } while (wait); 1427 } 1428 #endif 1429 1430 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 1431 { 1432 struct sk_buff *skb; 1433 u32 offset; 1434 1435 skb_queue_walk(&sk->sk_receive_queue, skb) { 1436 offset = seq - TCP_SKB_CB(skb)->seq; 1437 if (tcp_hdr(skb)->syn) 1438 offset--; 1439 if (offset < skb->len || tcp_hdr(skb)->fin) { 1440 *off = offset; 1441 return skb; 1442 } 1443 } 1444 return NULL; 1445 } 1446 1447 /* 1448 * This routine provides an alternative to tcp_recvmsg() for routines 1449 * that would like to handle copying from skbuffs directly in 'sendfile' 1450 * fashion. 1451 * Note: 1452 * - It is assumed that the socket was locked by the caller. 1453 * - The routine does not block. 1454 * - At present, there is no support for reading OOB data 1455 * or for 'peeking' the socket using this routine 1456 * (although both would be easy to implement). 1457 */ 1458 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 1459 sk_read_actor_t recv_actor) 1460 { 1461 struct sk_buff *skb; 1462 struct tcp_sock *tp = tcp_sk(sk); 1463 u32 seq = tp->copied_seq; 1464 u32 offset; 1465 int copied = 0; 1466 1467 if (sk->sk_state == TCP_LISTEN) 1468 return -ENOTCONN; 1469 while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { 1470 if (offset < skb->len) { 1471 int used; 1472 size_t len; 1473 1474 len = skb->len - offset; 1475 /* Stop reading if we hit a patch of urgent data */ 1476 if (tp->urg_data) { 1477 u32 urg_offset = tp->urg_seq - seq; 1478 if (urg_offset < len) 1479 len = urg_offset; 1480 if (!len) 1481 break; 1482 } 1483 used = recv_actor(desc, skb, offset, len); 1484 if (used < 0) { 1485 if (!copied) 1486 copied = used; 1487 break; 1488 } else if (used <= len) { 1489 seq += used; 1490 copied += used; 1491 offset += used; 1492 } 1493 /* 1494 * If recv_actor drops the lock (e.g. TCP splice 1495 * receive) the skb pointer might be invalid when 1496 * getting here: tcp_collapse might have deleted it 1497 * while aggregating skbs from the socket queue. 1498 */ 1499 skb = tcp_recv_skb(sk, seq-1, &offset); 1500 if (!skb || (offset+1 != skb->len)) 1501 break; 1502 } 1503 if (tcp_hdr(skb)->fin) { 1504 sk_eat_skb(sk, skb, false); 1505 ++seq; 1506 break; 1507 } 1508 sk_eat_skb(sk, skb, false); 1509 if (!desc->count) 1510 break; 1511 tp->copied_seq = seq; 1512 } 1513 tp->copied_seq = seq; 1514 1515 tcp_rcv_space_adjust(sk); 1516 1517 /* Clean up data we have read: This will do ACK frames. */ 1518 if (copied > 0) 1519 tcp_cleanup_rbuf(sk, copied); 1520 return copied; 1521 } 1522 EXPORT_SYMBOL(tcp_read_sock); 1523 1524 /* 1525 * This routine copies from a sock struct into the user buffer. 1526 * 1527 * Technical note: in 2.3 we work on _locked_ socket, so that 1528 * tricks with *seq access order and skb->users are not required. 1529 * Probably, code can be easily improved even more. 1530 */ 1531 1532 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 1533 size_t len, int nonblock, int flags, int *addr_len) 1534 { 1535 struct tcp_sock *tp = tcp_sk(sk); 1536 int copied = 0; 1537 u32 peek_seq; 1538 u32 *seq; 1539 unsigned long used; 1540 int err; 1541 int target; /* Read at least this many bytes */ 1542 long timeo; 1543 struct task_struct *user_recv = NULL; 1544 bool copied_early = false; 1545 struct sk_buff *skb; 1546 u32 urg_hole = 0; 1547 1548 lock_sock(sk); 1549 1550 err = -ENOTCONN; 1551 if (sk->sk_state == TCP_LISTEN) 1552 goto out; 1553 1554 timeo = sock_rcvtimeo(sk, nonblock); 1555 1556 /* Urgent data needs to be handled specially. */ 1557 if (flags & MSG_OOB) 1558 goto recv_urg; 1559 1560 if (unlikely(tp->repair)) { 1561 err = -EPERM; 1562 if (!(flags & MSG_PEEK)) 1563 goto out; 1564 1565 if (tp->repair_queue == TCP_SEND_QUEUE) 1566 goto recv_sndq; 1567 1568 err = -EINVAL; 1569 if (tp->repair_queue == TCP_NO_QUEUE) 1570 goto out; 1571 1572 /* 'common' recv queue MSG_PEEK-ing */ 1573 } 1574 1575 seq = &tp->copied_seq; 1576 if (flags & MSG_PEEK) { 1577 peek_seq = tp->copied_seq; 1578 seq = &peek_seq; 1579 } 1580 1581 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1582 1583 #ifdef CONFIG_NET_DMA 1584 tp->ucopy.dma_chan = NULL; 1585 preempt_disable(); 1586 skb = skb_peek_tail(&sk->sk_receive_queue); 1587 { 1588 int available = 0; 1589 1590 if (skb) 1591 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); 1592 if ((available < target) && 1593 (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && 1594 !sysctl_tcp_low_latency && 1595 net_dma_find_channel()) { 1596 preempt_enable_no_resched(); 1597 tp->ucopy.pinned_list = 1598 dma_pin_iovec_pages(msg->msg_iov, len); 1599 } else { 1600 preempt_enable_no_resched(); 1601 } 1602 } 1603 #endif 1604 1605 do { 1606 u32 offset; 1607 1608 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ 1609 if (tp->urg_data && tp->urg_seq == *seq) { 1610 if (copied) 1611 break; 1612 if (signal_pending(current)) { 1613 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN; 1614 break; 1615 } 1616 } 1617 1618 /* Next get a buffer. */ 1619 1620 skb_queue_walk(&sk->sk_receive_queue, skb) { 1621 /* Now that we have two receive queues this 1622 * shouldn't happen. 1623 */ 1624 if (WARN(before(*seq, TCP_SKB_CB(skb)->seq), 1625 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n", 1626 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, 1627 flags)) 1628 break; 1629 1630 offset = *seq - TCP_SKB_CB(skb)->seq; 1631 if (tcp_hdr(skb)->syn) 1632 offset--; 1633 if (offset < skb->len) 1634 goto found_ok_skb; 1635 if (tcp_hdr(skb)->fin) 1636 goto found_fin_ok; 1637 WARN(!(flags & MSG_PEEK), 1638 "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n", 1639 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags); 1640 } 1641 1642 /* Well, if we have backlog, try to process it now yet. */ 1643 1644 if (copied >= target && !sk->sk_backlog.tail) 1645 break; 1646 1647 if (copied) { 1648 if (sk->sk_err || 1649 sk->sk_state == TCP_CLOSE || 1650 (sk->sk_shutdown & RCV_SHUTDOWN) || 1651 !timeo || 1652 signal_pending(current)) 1653 break; 1654 } else { 1655 if (sock_flag(sk, SOCK_DONE)) 1656 break; 1657 1658 if (sk->sk_err) { 1659 copied = sock_error(sk); 1660 break; 1661 } 1662 1663 if (sk->sk_shutdown & RCV_SHUTDOWN) 1664 break; 1665 1666 if (sk->sk_state == TCP_CLOSE) { 1667 if (!sock_flag(sk, SOCK_DONE)) { 1668 /* This occurs when user tries to read 1669 * from never connected socket. 1670 */ 1671 copied = -ENOTCONN; 1672 break; 1673 } 1674 break; 1675 } 1676 1677 if (!timeo) { 1678 copied = -EAGAIN; 1679 break; 1680 } 1681 1682 if (signal_pending(current)) { 1683 copied = sock_intr_errno(timeo); 1684 break; 1685 } 1686 } 1687 1688 tcp_cleanup_rbuf(sk, copied); 1689 1690 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) { 1691 /* Install new reader */ 1692 if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) { 1693 user_recv = current; 1694 tp->ucopy.task = user_recv; 1695 tp->ucopy.iov = msg->msg_iov; 1696 } 1697 1698 tp->ucopy.len = len; 1699 1700 WARN_ON(tp->copied_seq != tp->rcv_nxt && 1701 !(flags & (MSG_PEEK | MSG_TRUNC))); 1702 1703 /* Ugly... If prequeue is not empty, we have to 1704 * process it before releasing socket, otherwise 1705 * order will be broken at second iteration. 1706 * More elegant solution is required!!! 1707 * 1708 * Look: we have the following (pseudo)queues: 1709 * 1710 * 1. packets in flight 1711 * 2. backlog 1712 * 3. prequeue 1713 * 4. receive_queue 1714 * 1715 * Each queue can be processed only if the next ones 1716 * are empty. At this point we have empty receive_queue. 1717 * But prequeue _can_ be not empty after 2nd iteration, 1718 * when we jumped to start of loop because backlog 1719 * processing added something to receive_queue. 1720 * We cannot release_sock(), because backlog contains 1721 * packets arrived _after_ prequeued ones. 1722 * 1723 * Shortly, algorithm is clear --- to process all 1724 * the queues in order. We could make it more directly, 1725 * requeueing packets from backlog to prequeue, if 1726 * is not empty. It is more elegant, but eats cycles, 1727 * unfortunately. 1728 */ 1729 if (!skb_queue_empty(&tp->ucopy.prequeue)) 1730 goto do_prequeue; 1731 1732 /* __ Set realtime policy in scheduler __ */ 1733 } 1734 1735 #ifdef CONFIG_NET_DMA 1736 if (tp->ucopy.dma_chan) { 1737 if (tp->rcv_wnd == 0 && 1738 !skb_queue_empty(&sk->sk_async_wait_queue)) { 1739 tcp_service_net_dma(sk, true); 1740 tcp_cleanup_rbuf(sk, copied); 1741 } else 1742 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1743 } 1744 #endif 1745 if (copied >= target) { 1746 /* Do not sleep, just process backlog. */ 1747 release_sock(sk); 1748 lock_sock(sk); 1749 } else 1750 sk_wait_data(sk, &timeo); 1751 1752 #ifdef CONFIG_NET_DMA 1753 tcp_service_net_dma(sk, false); /* Don't block */ 1754 tp->ucopy.wakeup = 0; 1755 #endif 1756 1757 if (user_recv) { 1758 int chunk; 1759 1760 /* __ Restore normal policy in scheduler __ */ 1761 1762 if ((chunk = len - tp->ucopy.len) != 0) { 1763 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk); 1764 len -= chunk; 1765 copied += chunk; 1766 } 1767 1768 if (tp->rcv_nxt == tp->copied_seq && 1769 !skb_queue_empty(&tp->ucopy.prequeue)) { 1770 do_prequeue: 1771 tcp_prequeue_process(sk); 1772 1773 if ((chunk = len - tp->ucopy.len) != 0) { 1774 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1775 len -= chunk; 1776 copied += chunk; 1777 } 1778 } 1779 } 1780 if ((flags & MSG_PEEK) && 1781 (peek_seq - copied - urg_hole != tp->copied_seq)) { 1782 net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n", 1783 current->comm, 1784 task_pid_nr(current)); 1785 peek_seq = tp->copied_seq; 1786 } 1787 continue; 1788 1789 found_ok_skb: 1790 /* Ok so how much can we use? */ 1791 used = skb->len - offset; 1792 if (len < used) 1793 used = len; 1794 1795 /* Do we have urgent data here? */ 1796 if (tp->urg_data) { 1797 u32 urg_offset = tp->urg_seq - *seq; 1798 if (urg_offset < used) { 1799 if (!urg_offset) { 1800 if (!sock_flag(sk, SOCK_URGINLINE)) { 1801 ++*seq; 1802 urg_hole++; 1803 offset++; 1804 used--; 1805 if (!used) 1806 goto skip_copy; 1807 } 1808 } else 1809 used = urg_offset; 1810 } 1811 } 1812 1813 if (!(flags & MSG_TRUNC)) { 1814 #ifdef CONFIG_NET_DMA 1815 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) 1816 tp->ucopy.dma_chan = net_dma_find_channel(); 1817 1818 if (tp->ucopy.dma_chan) { 1819 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec( 1820 tp->ucopy.dma_chan, skb, offset, 1821 msg->msg_iov, used, 1822 tp->ucopy.pinned_list); 1823 1824 if (tp->ucopy.dma_cookie < 0) { 1825 1826 pr_alert("%s: dma_cookie < 0\n", 1827 __func__); 1828 1829 /* Exception. Bailout! */ 1830 if (!copied) 1831 copied = -EFAULT; 1832 break; 1833 } 1834 1835 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); 1836 1837 if ((offset + used) == skb->len) 1838 copied_early = true; 1839 1840 } else 1841 #endif 1842 { 1843 err = skb_copy_datagram_iovec(skb, offset, 1844 msg->msg_iov, used); 1845 if (err) { 1846 /* Exception. Bailout! */ 1847 if (!copied) 1848 copied = -EFAULT; 1849 break; 1850 } 1851 } 1852 } 1853 1854 *seq += used; 1855 copied += used; 1856 len -= used; 1857 1858 tcp_rcv_space_adjust(sk); 1859 1860 skip_copy: 1861 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) { 1862 tp->urg_data = 0; 1863 tcp_fast_path_check(sk); 1864 } 1865 if (used + offset < skb->len) 1866 continue; 1867 1868 if (tcp_hdr(skb)->fin) 1869 goto found_fin_ok; 1870 if (!(flags & MSG_PEEK)) { 1871 sk_eat_skb(sk, skb, copied_early); 1872 copied_early = false; 1873 } 1874 continue; 1875 1876 found_fin_ok: 1877 /* Process the FIN. */ 1878 ++*seq; 1879 if (!(flags & MSG_PEEK)) { 1880 sk_eat_skb(sk, skb, copied_early); 1881 copied_early = false; 1882 } 1883 break; 1884 } while (len > 0); 1885 1886 if (user_recv) { 1887 if (!skb_queue_empty(&tp->ucopy.prequeue)) { 1888 int chunk; 1889 1890 tp->ucopy.len = copied > 0 ? len : 0; 1891 1892 tcp_prequeue_process(sk); 1893 1894 if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) { 1895 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk); 1896 len -= chunk; 1897 copied += chunk; 1898 } 1899 } 1900 1901 tp->ucopy.task = NULL; 1902 tp->ucopy.len = 0; 1903 } 1904 1905 #ifdef CONFIG_NET_DMA 1906 tcp_service_net_dma(sk, true); /* Wait for queue to drain */ 1907 tp->ucopy.dma_chan = NULL; 1908 1909 if (tp->ucopy.pinned_list) { 1910 dma_unpin_iovec_pages(tp->ucopy.pinned_list); 1911 tp->ucopy.pinned_list = NULL; 1912 } 1913 #endif 1914 1915 /* According to UNIX98, msg_name/msg_namelen are ignored 1916 * on connected socket. I was just happy when found this 8) --ANK 1917 */ 1918 1919 /* Clean up data we have read: This will do ACK frames. */ 1920 tcp_cleanup_rbuf(sk, copied); 1921 1922 release_sock(sk); 1923 return copied; 1924 1925 out: 1926 release_sock(sk); 1927 return err; 1928 1929 recv_urg: 1930 err = tcp_recv_urg(sk, msg, len, flags); 1931 goto out; 1932 1933 recv_sndq: 1934 err = tcp_peek_sndq(sk, msg, len); 1935 goto out; 1936 } 1937 EXPORT_SYMBOL(tcp_recvmsg); 1938 1939 void tcp_set_state(struct sock *sk, int state) 1940 { 1941 int oldstate = sk->sk_state; 1942 1943 switch (state) { 1944 case TCP_ESTABLISHED: 1945 if (oldstate != TCP_ESTABLISHED) 1946 TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1947 break; 1948 1949 case TCP_CLOSE: 1950 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 1951 TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS); 1952 1953 sk->sk_prot->unhash(sk); 1954 if (inet_csk(sk)->icsk_bind_hash && 1955 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 1956 inet_put_port(sk); 1957 /* fall through */ 1958 default: 1959 if (oldstate == TCP_ESTABLISHED) 1960 TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB); 1961 } 1962 1963 /* Change state AFTER socket is unhashed to avoid closed 1964 * socket sitting in hash tables. 1965 */ 1966 sk->sk_state = state; 1967 1968 #ifdef STATE_TRACE 1969 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]); 1970 #endif 1971 } 1972 EXPORT_SYMBOL_GPL(tcp_set_state); 1973 1974 /* 1975 * State processing on a close. This implements the state shift for 1976 * sending our FIN frame. Note that we only send a FIN for some 1977 * states. A shutdown() may have already sent the FIN, or we may be 1978 * closed. 1979 */ 1980 1981 static const unsigned char new_state[16] = { 1982 /* current state: new state: action: */ 1983 /* (Invalid) */ TCP_CLOSE, 1984 /* TCP_ESTABLISHED */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1985 /* TCP_SYN_SENT */ TCP_CLOSE, 1986 /* TCP_SYN_RECV */ TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1987 /* TCP_FIN_WAIT1 */ TCP_FIN_WAIT1, 1988 /* TCP_FIN_WAIT2 */ TCP_FIN_WAIT2, 1989 /* TCP_TIME_WAIT */ TCP_CLOSE, 1990 /* TCP_CLOSE */ TCP_CLOSE, 1991 /* TCP_CLOSE_WAIT */ TCP_LAST_ACK | TCP_ACTION_FIN, 1992 /* TCP_LAST_ACK */ TCP_LAST_ACK, 1993 /* TCP_LISTEN */ TCP_CLOSE, 1994 /* TCP_CLOSING */ TCP_CLOSING, 1995 }; 1996 1997 static int tcp_close_state(struct sock *sk) 1998 { 1999 int next = (int)new_state[sk->sk_state]; 2000 int ns = next & TCP_STATE_MASK; 2001 2002 tcp_set_state(sk, ns); 2003 2004 return next & TCP_ACTION_FIN; 2005 } 2006 2007 /* 2008 * Shutdown the sending side of a connection. Much like close except 2009 * that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD). 2010 */ 2011 2012 void tcp_shutdown(struct sock *sk, int how) 2013 { 2014 /* We need to grab some memory, and put together a FIN, 2015 * and then put it into the queue to be sent. 2016 * Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92. 2017 */ 2018 if (!(how & SEND_SHUTDOWN)) 2019 return; 2020 2021 /* If we've already sent a FIN, or it's a closed state, skip this. */ 2022 if ((1 << sk->sk_state) & 2023 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 2024 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) { 2025 /* Clear out any half completed packets. FIN if needed. */ 2026 if (tcp_close_state(sk)) 2027 tcp_send_fin(sk); 2028 } 2029 } 2030 EXPORT_SYMBOL(tcp_shutdown); 2031 2032 bool tcp_check_oom(struct sock *sk, int shift) 2033 { 2034 bool too_many_orphans, out_of_socket_memory; 2035 2036 too_many_orphans = tcp_too_many_orphans(sk, shift); 2037 out_of_socket_memory = tcp_out_of_memory(sk); 2038 2039 if (too_many_orphans) 2040 net_info_ratelimited("too many orphaned sockets\n"); 2041 if (out_of_socket_memory) 2042 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n"); 2043 return too_many_orphans || out_of_socket_memory; 2044 } 2045 2046 void tcp_close(struct sock *sk, long timeout) 2047 { 2048 struct sk_buff *skb; 2049 int data_was_unread = 0; 2050 int state; 2051 2052 lock_sock(sk); 2053 sk->sk_shutdown = SHUTDOWN_MASK; 2054 2055 if (sk->sk_state == TCP_LISTEN) { 2056 tcp_set_state(sk, TCP_CLOSE); 2057 2058 /* Special case. */ 2059 inet_csk_listen_stop(sk); 2060 2061 goto adjudge_to_death; 2062 } 2063 2064 /* We need to flush the recv. buffs. We do this only on the 2065 * descriptor close, not protocol-sourced closes, because the 2066 * reader process may not have drained the data yet! 2067 */ 2068 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) { 2069 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq - 2070 tcp_hdr(skb)->fin; 2071 data_was_unread += len; 2072 __kfree_skb(skb); 2073 } 2074 2075 sk_mem_reclaim(sk); 2076 2077 /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */ 2078 if (sk->sk_state == TCP_CLOSE) 2079 goto adjudge_to_death; 2080 2081 /* As outlined in RFC 2525, section 2.17, we send a RST here because 2082 * data was lost. To witness the awful effects of the old behavior of 2083 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk 2084 * GET in an FTP client, suspend the process, wait for the client to 2085 * advertise a zero window, then kill -9 the FTP client, wheee... 2086 * Note: timeout is always zero in such a case. 2087 */ 2088 if (unlikely(tcp_sk(sk)->repair)) { 2089 sk->sk_prot->disconnect(sk, 0); 2090 } else if (data_was_unread) { 2091 /* Unread data was tossed, zap the connection. */ 2092 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE); 2093 tcp_set_state(sk, TCP_CLOSE); 2094 tcp_send_active_reset(sk, sk->sk_allocation); 2095 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) { 2096 /* Check zero linger _after_ checking for unread data. */ 2097 sk->sk_prot->disconnect(sk, 0); 2098 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA); 2099 } else if (tcp_close_state(sk)) { 2100 /* We FIN if the application ate all the data before 2101 * zapping the connection. 2102 */ 2103 2104 /* RED-PEN. Formally speaking, we have broken TCP state 2105 * machine. State transitions: 2106 * 2107 * TCP_ESTABLISHED -> TCP_FIN_WAIT1 2108 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible) 2109 * TCP_CLOSE_WAIT -> TCP_LAST_ACK 2110 * 2111 * are legal only when FIN has been sent (i.e. in window), 2112 * rather than queued out of window. Purists blame. 2113 * 2114 * F.e. "RFC state" is ESTABLISHED, 2115 * if Linux state is FIN-WAIT-1, but FIN is still not sent. 2116 * 2117 * The visible declinations are that sometimes 2118 * we enter time-wait state, when it is not required really 2119 * (harmless), do not send active resets, when they are 2120 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when 2121 * they look as CLOSING or LAST_ACK for Linux) 2122 * Probably, I missed some more holelets. 2123 * --ANK 2124 * XXX (TFO) - To start off we don't support SYN+ACK+FIN 2125 * in a single packet! (May consider it later but will 2126 * probably need API support or TCP_CORK SYN-ACK until 2127 * data is written and socket is closed.) 2128 */ 2129 tcp_send_fin(sk); 2130 } 2131 2132 sk_stream_wait_close(sk, timeout); 2133 2134 adjudge_to_death: 2135 state = sk->sk_state; 2136 sock_hold(sk); 2137 sock_orphan(sk); 2138 2139 /* It is the last release_sock in its life. It will remove backlog. */ 2140 release_sock(sk); 2141 2142 2143 /* Now socket is owned by kernel and we acquire BH lock 2144 to finish close. No need to check for user refs. 2145 */ 2146 local_bh_disable(); 2147 bh_lock_sock(sk); 2148 WARN_ON(sock_owned_by_user(sk)); 2149 2150 percpu_counter_inc(sk->sk_prot->orphan_count); 2151 2152 /* Have we already been destroyed by a softirq or backlog? */ 2153 if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE) 2154 goto out; 2155 2156 /* This is a (useful) BSD violating of the RFC. There is a 2157 * problem with TCP as specified in that the other end could 2158 * keep a socket open forever with no application left this end. 2159 * We use a 3 minute timeout (about the same as BSD) then kill 2160 * our end. If they send after that then tough - BUT: long enough 2161 * that we won't make the old 4*rto = almost no time - whoops 2162 * reset mistake. 2163 * 2164 * Nope, it was not mistake. It is really desired behaviour 2165 * f.e. on http servers, when such sockets are useless, but 2166 * consume significant resources. Let's do it with special 2167 * linger2 option. --ANK 2168 */ 2169 2170 if (sk->sk_state == TCP_FIN_WAIT2) { 2171 struct tcp_sock *tp = tcp_sk(sk); 2172 if (tp->linger2 < 0) { 2173 tcp_set_state(sk, TCP_CLOSE); 2174 tcp_send_active_reset(sk, GFP_ATOMIC); 2175 NET_INC_STATS_BH(sock_net(sk), 2176 LINUX_MIB_TCPABORTONLINGER); 2177 } else { 2178 const int tmo = tcp_fin_time(sk); 2179 2180 if (tmo > TCP_TIMEWAIT_LEN) { 2181 inet_csk_reset_keepalive_timer(sk, 2182 tmo - TCP_TIMEWAIT_LEN); 2183 } else { 2184 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); 2185 goto out; 2186 } 2187 } 2188 } 2189 if (sk->sk_state != TCP_CLOSE) { 2190 sk_mem_reclaim(sk); 2191 if (tcp_check_oom(sk, 0)) { 2192 tcp_set_state(sk, TCP_CLOSE); 2193 tcp_send_active_reset(sk, GFP_ATOMIC); 2194 NET_INC_STATS_BH(sock_net(sk), 2195 LINUX_MIB_TCPABORTONMEMORY); 2196 } 2197 } 2198 2199 if (sk->sk_state == TCP_CLOSE) { 2200 struct request_sock *req = tcp_sk(sk)->fastopen_rsk; 2201 /* We could get here with a non-NULL req if the socket is 2202 * aborted (e.g., closed with unread data) before 3WHS 2203 * finishes. 2204 */ 2205 if (req != NULL) 2206 reqsk_fastopen_remove(sk, req, false); 2207 inet_csk_destroy_sock(sk); 2208 } 2209 /* Otherwise, socket is reprieved until protocol close. */ 2210 2211 out: 2212 bh_unlock_sock(sk); 2213 local_bh_enable(); 2214 sock_put(sk); 2215 } 2216 EXPORT_SYMBOL(tcp_close); 2217 2218 /* These states need RST on ABORT according to RFC793 */ 2219 2220 static inline bool tcp_need_reset(int state) 2221 { 2222 return (1 << state) & 2223 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 | 2224 TCPF_FIN_WAIT2 | TCPF_SYN_RECV); 2225 } 2226 2227 int tcp_disconnect(struct sock *sk, int flags) 2228 { 2229 struct inet_sock *inet = inet_sk(sk); 2230 struct inet_connection_sock *icsk = inet_csk(sk); 2231 struct tcp_sock *tp = tcp_sk(sk); 2232 int err = 0; 2233 int old_state = sk->sk_state; 2234 2235 if (old_state != TCP_CLOSE) 2236 tcp_set_state(sk, TCP_CLOSE); 2237 2238 /* ABORT function of RFC793 */ 2239 if (old_state == TCP_LISTEN) { 2240 inet_csk_listen_stop(sk); 2241 } else if (unlikely(tp->repair)) { 2242 sk->sk_err = ECONNABORTED; 2243 } else if (tcp_need_reset(old_state) || 2244 (tp->snd_nxt != tp->write_seq && 2245 (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) { 2246 /* The last check adjusts for discrepancy of Linux wrt. RFC 2247 * states 2248 */ 2249 tcp_send_active_reset(sk, gfp_any()); 2250 sk->sk_err = ECONNRESET; 2251 } else if (old_state == TCP_SYN_SENT) 2252 sk->sk_err = ECONNRESET; 2253 2254 tcp_clear_xmit_timers(sk); 2255 __skb_queue_purge(&sk->sk_receive_queue); 2256 tcp_write_queue_purge(sk); 2257 __skb_queue_purge(&tp->out_of_order_queue); 2258 #ifdef CONFIG_NET_DMA 2259 __skb_queue_purge(&sk->sk_async_wait_queue); 2260 #endif 2261 2262 inet->inet_dport = 0; 2263 2264 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) 2265 inet_reset_saddr(sk); 2266 2267 sk->sk_shutdown = 0; 2268 sock_reset_flag(sk, SOCK_DONE); 2269 tp->srtt = 0; 2270 if ((tp->write_seq += tp->max_window + 2) == 0) 2271 tp->write_seq = 1; 2272 icsk->icsk_backoff = 0; 2273 tp->snd_cwnd = 2; 2274 icsk->icsk_probes_out = 0; 2275 tp->packets_out = 0; 2276 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; 2277 tp->snd_cwnd_cnt = 0; 2278 tp->bytes_acked = 0; 2279 tp->window_clamp = 0; 2280 tcp_set_ca_state(sk, TCP_CA_Open); 2281 tcp_clear_retrans(tp); 2282 inet_csk_delack_init(sk); 2283 tcp_init_send_head(sk); 2284 memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); 2285 __sk_dst_reset(sk); 2286 2287 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash); 2288 2289 sk->sk_error_report(sk); 2290 return err; 2291 } 2292 EXPORT_SYMBOL(tcp_disconnect); 2293 2294 void tcp_sock_destruct(struct sock *sk) 2295 { 2296 inet_sock_destruct(sk); 2297 2298 kfree(inet_csk(sk)->icsk_accept_queue.fastopenq); 2299 } 2300 2301 static inline bool tcp_can_repair_sock(const struct sock *sk) 2302 { 2303 return capable(CAP_NET_ADMIN) && 2304 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED)); 2305 } 2306 2307 static int tcp_repair_options_est(struct tcp_sock *tp, 2308 struct tcp_repair_opt __user *optbuf, unsigned int len) 2309 { 2310 struct tcp_repair_opt opt; 2311 2312 while (len >= sizeof(opt)) { 2313 if (copy_from_user(&opt, optbuf, sizeof(opt))) 2314 return -EFAULT; 2315 2316 optbuf++; 2317 len -= sizeof(opt); 2318 2319 switch (opt.opt_code) { 2320 case TCPOPT_MSS: 2321 tp->rx_opt.mss_clamp = opt.opt_val; 2322 break; 2323 case TCPOPT_WINDOW: 2324 { 2325 u16 snd_wscale = opt.opt_val & 0xFFFF; 2326 u16 rcv_wscale = opt.opt_val >> 16; 2327 2328 if (snd_wscale > 14 || rcv_wscale > 14) 2329 return -EFBIG; 2330 2331 tp->rx_opt.snd_wscale = snd_wscale; 2332 tp->rx_opt.rcv_wscale = rcv_wscale; 2333 tp->rx_opt.wscale_ok = 1; 2334 } 2335 break; 2336 case TCPOPT_SACK_PERM: 2337 if (opt.opt_val != 0) 2338 return -EINVAL; 2339 2340 tp->rx_opt.sack_ok |= TCP_SACK_SEEN; 2341 if (sysctl_tcp_fack) 2342 tcp_enable_fack(tp); 2343 break; 2344 case TCPOPT_TIMESTAMP: 2345 if (opt.opt_val != 0) 2346 return -EINVAL; 2347 2348 tp->rx_opt.tstamp_ok = 1; 2349 break; 2350 } 2351 } 2352 2353 return 0; 2354 } 2355 2356 /* 2357 * Socket option code for TCP. 2358 */ 2359 static int do_tcp_setsockopt(struct sock *sk, int level, 2360 int optname, char __user *optval, unsigned int optlen) 2361 { 2362 struct tcp_sock *tp = tcp_sk(sk); 2363 struct inet_connection_sock *icsk = inet_csk(sk); 2364 int val; 2365 int err = 0; 2366 2367 /* These are data/string values, all the others are ints */ 2368 switch (optname) { 2369 case TCP_CONGESTION: { 2370 char name[TCP_CA_NAME_MAX]; 2371 2372 if (optlen < 1) 2373 return -EINVAL; 2374 2375 val = strncpy_from_user(name, optval, 2376 min_t(long, TCP_CA_NAME_MAX-1, optlen)); 2377 if (val < 0) 2378 return -EFAULT; 2379 name[val] = 0; 2380 2381 lock_sock(sk); 2382 err = tcp_set_congestion_control(sk, name); 2383 release_sock(sk); 2384 return err; 2385 } 2386 case TCP_COOKIE_TRANSACTIONS: { 2387 struct tcp_cookie_transactions ctd; 2388 struct tcp_cookie_values *cvp = NULL; 2389 2390 if (sizeof(ctd) > optlen) 2391 return -EINVAL; 2392 if (copy_from_user(&ctd, optval, sizeof(ctd))) 2393 return -EFAULT; 2394 2395 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) || 2396 ctd.tcpct_s_data_desired > TCP_MSS_DESIRED) 2397 return -EINVAL; 2398 2399 if (ctd.tcpct_cookie_desired == 0) { 2400 /* default to global value */ 2401 } else if ((0x1 & ctd.tcpct_cookie_desired) || 2402 ctd.tcpct_cookie_desired > TCP_COOKIE_MAX || 2403 ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) { 2404 return -EINVAL; 2405 } 2406 2407 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) { 2408 /* Supercedes all other values */ 2409 lock_sock(sk); 2410 if (tp->cookie_values != NULL) { 2411 kref_put(&tp->cookie_values->kref, 2412 tcp_cookie_values_release); 2413 tp->cookie_values = NULL; 2414 } 2415 tp->rx_opt.cookie_in_always = 0; /* false */ 2416 tp->rx_opt.cookie_out_never = 1; /* true */ 2417 release_sock(sk); 2418 return err; 2419 } 2420 2421 /* Allocate ancillary memory before locking. 2422 */ 2423 if (ctd.tcpct_used > 0 || 2424 (tp->cookie_values == NULL && 2425 (sysctl_tcp_cookie_size > 0 || 2426 ctd.tcpct_cookie_desired > 0 || 2427 ctd.tcpct_s_data_desired > 0))) { 2428 cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used, 2429 GFP_KERNEL); 2430 if (cvp == NULL) 2431 return -ENOMEM; 2432 2433 kref_init(&cvp->kref); 2434 } 2435 lock_sock(sk); 2436 tp->rx_opt.cookie_in_always = 2437 (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags); 2438 tp->rx_opt.cookie_out_never = 0; /* false */ 2439 2440 if (tp->cookie_values != NULL) { 2441 if (cvp != NULL) { 2442 /* Changed values are recorded by a changed 2443 * pointer, ensuring the cookie will differ, 2444 * without separately hashing each value later. 2445 */ 2446 kref_put(&tp->cookie_values->kref, 2447 tcp_cookie_values_release); 2448 } else { 2449 cvp = tp->cookie_values; 2450 } 2451 } 2452 2453 if (cvp != NULL) { 2454 cvp->cookie_desired = ctd.tcpct_cookie_desired; 2455 2456 if (ctd.tcpct_used > 0) { 2457 memcpy(cvp->s_data_payload, ctd.tcpct_value, 2458 ctd.tcpct_used); 2459 cvp->s_data_desired = ctd.tcpct_used; 2460 cvp->s_data_constant = 1; /* true */ 2461 } else { 2462 /* No constant payload data. */ 2463 cvp->s_data_desired = ctd.tcpct_s_data_desired; 2464 cvp->s_data_constant = 0; /* false */ 2465 } 2466 2467 tp->cookie_values = cvp; 2468 } 2469 release_sock(sk); 2470 return err; 2471 } 2472 default: 2473 /* fallthru */ 2474 break; 2475 } 2476 2477 if (optlen < sizeof(int)) 2478 return -EINVAL; 2479 2480 if (get_user(val, (int __user *)optval)) 2481 return -EFAULT; 2482 2483 lock_sock(sk); 2484 2485 switch (optname) { 2486 case TCP_MAXSEG: 2487 /* Values greater than interface MTU won't take effect. However 2488 * at the point when this call is done we typically don't yet 2489 * know which interface is going to be used */ 2490 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) { 2491 err = -EINVAL; 2492 break; 2493 } 2494 tp->rx_opt.user_mss = val; 2495 break; 2496 2497 case TCP_NODELAY: 2498 if (val) { 2499 /* TCP_NODELAY is weaker than TCP_CORK, so that 2500 * this option on corked socket is remembered, but 2501 * it is not activated until cork is cleared. 2502 * 2503 * However, when TCP_NODELAY is set we make 2504 * an explicit push, which overrides even TCP_CORK 2505 * for currently queued segments. 2506 */ 2507 tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH; 2508 tcp_push_pending_frames(sk); 2509 } else { 2510 tp->nonagle &= ~TCP_NAGLE_OFF; 2511 } 2512 break; 2513 2514 case TCP_THIN_LINEAR_TIMEOUTS: 2515 if (val < 0 || val > 1) 2516 err = -EINVAL; 2517 else 2518 tp->thin_lto = val; 2519 break; 2520 2521 case TCP_THIN_DUPACK: 2522 if (val < 0 || val > 1) 2523 err = -EINVAL; 2524 else 2525 tp->thin_dupack = val; 2526 if (tp->thin_dupack) 2527 tcp_disable_early_retrans(tp); 2528 break; 2529 2530 case TCP_REPAIR: 2531 if (!tcp_can_repair_sock(sk)) 2532 err = -EPERM; 2533 else if (val == 1) { 2534 tp->repair = 1; 2535 sk->sk_reuse = SK_FORCE_REUSE; 2536 tp->repair_queue = TCP_NO_QUEUE; 2537 } else if (val == 0) { 2538 tp->repair = 0; 2539 sk->sk_reuse = SK_NO_REUSE; 2540 tcp_send_window_probe(sk); 2541 } else 2542 err = -EINVAL; 2543 2544 break; 2545 2546 case TCP_REPAIR_QUEUE: 2547 if (!tp->repair) 2548 err = -EPERM; 2549 else if (val < TCP_QUEUES_NR) 2550 tp->repair_queue = val; 2551 else 2552 err = -EINVAL; 2553 break; 2554 2555 case TCP_QUEUE_SEQ: 2556 if (sk->sk_state != TCP_CLOSE) 2557 err = -EPERM; 2558 else if (tp->repair_queue == TCP_SEND_QUEUE) 2559 tp->write_seq = val; 2560 else if (tp->repair_queue == TCP_RECV_QUEUE) 2561 tp->rcv_nxt = val; 2562 else 2563 err = -EINVAL; 2564 break; 2565 2566 case TCP_REPAIR_OPTIONS: 2567 if (!tp->repair) 2568 err = -EINVAL; 2569 else if (sk->sk_state == TCP_ESTABLISHED) 2570 err = tcp_repair_options_est(tp, 2571 (struct tcp_repair_opt __user *)optval, 2572 optlen); 2573 else 2574 err = -EPERM; 2575 break; 2576 2577 case TCP_CORK: 2578 /* When set indicates to always queue non-full frames. 2579 * Later the user clears this option and we transmit 2580 * any pending partial frames in the queue. This is 2581 * meant to be used alongside sendfile() to get properly 2582 * filled frames when the user (for example) must write 2583 * out headers with a write() call first and then use 2584 * sendfile to send out the data parts. 2585 * 2586 * TCP_CORK can be set together with TCP_NODELAY and it is 2587 * stronger than TCP_NODELAY. 2588 */ 2589 if (val) { 2590 tp->nonagle |= TCP_NAGLE_CORK; 2591 } else { 2592 tp->nonagle &= ~TCP_NAGLE_CORK; 2593 if (tp->nonagle&TCP_NAGLE_OFF) 2594 tp->nonagle |= TCP_NAGLE_PUSH; 2595 tcp_push_pending_frames(sk); 2596 } 2597 break; 2598 2599 case TCP_KEEPIDLE: 2600 if (val < 1 || val > MAX_TCP_KEEPIDLE) 2601 err = -EINVAL; 2602 else { 2603 tp->keepalive_time = val * HZ; 2604 if (sock_flag(sk, SOCK_KEEPOPEN) && 2605 !((1 << sk->sk_state) & 2606 (TCPF_CLOSE | TCPF_LISTEN))) { 2607 u32 elapsed = keepalive_time_elapsed(tp); 2608 if (tp->keepalive_time > elapsed) 2609 elapsed = tp->keepalive_time - elapsed; 2610 else 2611 elapsed = 0; 2612 inet_csk_reset_keepalive_timer(sk, elapsed); 2613 } 2614 } 2615 break; 2616 case TCP_KEEPINTVL: 2617 if (val < 1 || val > MAX_TCP_KEEPINTVL) 2618 err = -EINVAL; 2619 else 2620 tp->keepalive_intvl = val * HZ; 2621 break; 2622 case TCP_KEEPCNT: 2623 if (val < 1 || val > MAX_TCP_KEEPCNT) 2624 err = -EINVAL; 2625 else 2626 tp->keepalive_probes = val; 2627 break; 2628 case TCP_SYNCNT: 2629 if (val < 1 || val > MAX_TCP_SYNCNT) 2630 err = -EINVAL; 2631 else 2632 icsk->icsk_syn_retries = val; 2633 break; 2634 2635 case TCP_LINGER2: 2636 if (val < 0) 2637 tp->linger2 = -1; 2638 else if (val > sysctl_tcp_fin_timeout / HZ) 2639 tp->linger2 = 0; 2640 else 2641 tp->linger2 = val * HZ; 2642 break; 2643 2644 case TCP_DEFER_ACCEPT: 2645 /* Translate value in seconds to number of retransmits */ 2646 icsk->icsk_accept_queue.rskq_defer_accept = 2647 secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ, 2648 TCP_RTO_MAX / HZ); 2649 break; 2650 2651 case TCP_WINDOW_CLAMP: 2652 if (!val) { 2653 if (sk->sk_state != TCP_CLOSE) { 2654 err = -EINVAL; 2655 break; 2656 } 2657 tp->window_clamp = 0; 2658 } else 2659 tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ? 2660 SOCK_MIN_RCVBUF / 2 : val; 2661 break; 2662 2663 case TCP_QUICKACK: 2664 if (!val) { 2665 icsk->icsk_ack.pingpong = 1; 2666 } else { 2667 icsk->icsk_ack.pingpong = 0; 2668 if ((1 << sk->sk_state) & 2669 (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) && 2670 inet_csk_ack_scheduled(sk)) { 2671 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; 2672 tcp_cleanup_rbuf(sk, 1); 2673 if (!(val & 1)) 2674 icsk->icsk_ack.pingpong = 1; 2675 } 2676 } 2677 break; 2678 2679 #ifdef CONFIG_TCP_MD5SIG 2680 case TCP_MD5SIG: 2681 /* Read the IP->Key mappings from userspace */ 2682 err = tp->af_specific->md5_parse(sk, optval, optlen); 2683 break; 2684 #endif 2685 case TCP_USER_TIMEOUT: 2686 /* Cap the max timeout in ms TCP will retry/retrans 2687 * before giving up and aborting (ETIMEDOUT) a connection. 2688 */ 2689 if (val < 0) 2690 err = -EINVAL; 2691 else 2692 icsk->icsk_user_timeout = msecs_to_jiffies(val); 2693 break; 2694 2695 case TCP_FASTOPEN: 2696 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE | 2697 TCPF_LISTEN))) 2698 err = fastopen_init_queue(sk, val); 2699 else 2700 err = -EINVAL; 2701 break; 2702 default: 2703 err = -ENOPROTOOPT; 2704 break; 2705 } 2706 2707 release_sock(sk); 2708 return err; 2709 } 2710 2711 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 2712 unsigned int optlen) 2713 { 2714 const struct inet_connection_sock *icsk = inet_csk(sk); 2715 2716 if (level != SOL_TCP) 2717 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 2718 optval, optlen); 2719 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2720 } 2721 EXPORT_SYMBOL(tcp_setsockopt); 2722 2723 #ifdef CONFIG_COMPAT 2724 int compat_tcp_setsockopt(struct sock *sk, int level, int optname, 2725 char __user *optval, unsigned int optlen) 2726 { 2727 if (level != SOL_TCP) 2728 return inet_csk_compat_setsockopt(sk, level, optname, 2729 optval, optlen); 2730 return do_tcp_setsockopt(sk, level, optname, optval, optlen); 2731 } 2732 EXPORT_SYMBOL(compat_tcp_setsockopt); 2733 #endif 2734 2735 /* Return information about state of tcp endpoint in API format. */ 2736 void tcp_get_info(const struct sock *sk, struct tcp_info *info) 2737 { 2738 const struct tcp_sock *tp = tcp_sk(sk); 2739 const struct inet_connection_sock *icsk = inet_csk(sk); 2740 u32 now = tcp_time_stamp; 2741 2742 memset(info, 0, sizeof(*info)); 2743 2744 info->tcpi_state = sk->sk_state; 2745 info->tcpi_ca_state = icsk->icsk_ca_state; 2746 info->tcpi_retransmits = icsk->icsk_retransmits; 2747 info->tcpi_probes = icsk->icsk_probes_out; 2748 info->tcpi_backoff = icsk->icsk_backoff; 2749 2750 if (tp->rx_opt.tstamp_ok) 2751 info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 2752 if (tcp_is_sack(tp)) 2753 info->tcpi_options |= TCPI_OPT_SACK; 2754 if (tp->rx_opt.wscale_ok) { 2755 info->tcpi_options |= TCPI_OPT_WSCALE; 2756 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale; 2757 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale; 2758 } 2759 2760 if (tp->ecn_flags & TCP_ECN_OK) 2761 info->tcpi_options |= TCPI_OPT_ECN; 2762 if (tp->ecn_flags & TCP_ECN_SEEN) 2763 info->tcpi_options |= TCPI_OPT_ECN_SEEN; 2764 if (tp->syn_data_acked) 2765 info->tcpi_options |= TCPI_OPT_SYN_DATA; 2766 2767 info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto); 2768 info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato); 2769 info->tcpi_snd_mss = tp->mss_cache; 2770 info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss; 2771 2772 if (sk->sk_state == TCP_LISTEN) { 2773 info->tcpi_unacked = sk->sk_ack_backlog; 2774 info->tcpi_sacked = sk->sk_max_ack_backlog; 2775 } else { 2776 info->tcpi_unacked = tp->packets_out; 2777 info->tcpi_sacked = tp->sacked_out; 2778 } 2779 info->tcpi_lost = tp->lost_out; 2780 info->tcpi_retrans = tp->retrans_out; 2781 info->tcpi_fackets = tp->fackets_out; 2782 2783 info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime); 2784 info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime); 2785 info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp); 2786 2787 info->tcpi_pmtu = icsk->icsk_pmtu_cookie; 2788 info->tcpi_rcv_ssthresh = tp->rcv_ssthresh; 2789 info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3; 2790 info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2; 2791 info->tcpi_snd_ssthresh = tp->snd_ssthresh; 2792 info->tcpi_snd_cwnd = tp->snd_cwnd; 2793 info->tcpi_advmss = tp->advmss; 2794 info->tcpi_reordering = tp->reordering; 2795 2796 info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3; 2797 info->tcpi_rcv_space = tp->rcvq_space.space; 2798 2799 info->tcpi_total_retrans = tp->total_retrans; 2800 } 2801 EXPORT_SYMBOL_GPL(tcp_get_info); 2802 2803 static int do_tcp_getsockopt(struct sock *sk, int level, 2804 int optname, char __user *optval, int __user *optlen) 2805 { 2806 struct inet_connection_sock *icsk = inet_csk(sk); 2807 struct tcp_sock *tp = tcp_sk(sk); 2808 int val, len; 2809 2810 if (get_user(len, optlen)) 2811 return -EFAULT; 2812 2813 len = min_t(unsigned int, len, sizeof(int)); 2814 2815 if (len < 0) 2816 return -EINVAL; 2817 2818 switch (optname) { 2819 case TCP_MAXSEG: 2820 val = tp->mss_cache; 2821 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 2822 val = tp->rx_opt.user_mss; 2823 if (tp->repair) 2824 val = tp->rx_opt.mss_clamp; 2825 break; 2826 case TCP_NODELAY: 2827 val = !!(tp->nonagle&TCP_NAGLE_OFF); 2828 break; 2829 case TCP_CORK: 2830 val = !!(tp->nonagle&TCP_NAGLE_CORK); 2831 break; 2832 case TCP_KEEPIDLE: 2833 val = keepalive_time_when(tp) / HZ; 2834 break; 2835 case TCP_KEEPINTVL: 2836 val = keepalive_intvl_when(tp) / HZ; 2837 break; 2838 case TCP_KEEPCNT: 2839 val = keepalive_probes(tp); 2840 break; 2841 case TCP_SYNCNT: 2842 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; 2843 break; 2844 case TCP_LINGER2: 2845 val = tp->linger2; 2846 if (val >= 0) 2847 val = (val ? : sysctl_tcp_fin_timeout) / HZ; 2848 break; 2849 case TCP_DEFER_ACCEPT: 2850 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept, 2851 TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ); 2852 break; 2853 case TCP_WINDOW_CLAMP: 2854 val = tp->window_clamp; 2855 break; 2856 case TCP_INFO: { 2857 struct tcp_info info; 2858 2859 if (get_user(len, optlen)) 2860 return -EFAULT; 2861 2862 tcp_get_info(sk, &info); 2863 2864 len = min_t(unsigned int, len, sizeof(info)); 2865 if (put_user(len, optlen)) 2866 return -EFAULT; 2867 if (copy_to_user(optval, &info, len)) 2868 return -EFAULT; 2869 return 0; 2870 } 2871 case TCP_QUICKACK: 2872 val = !icsk->icsk_ack.pingpong; 2873 break; 2874 2875 case TCP_CONGESTION: 2876 if (get_user(len, optlen)) 2877 return -EFAULT; 2878 len = min_t(unsigned int, len, TCP_CA_NAME_MAX); 2879 if (put_user(len, optlen)) 2880 return -EFAULT; 2881 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) 2882 return -EFAULT; 2883 return 0; 2884 2885 case TCP_COOKIE_TRANSACTIONS: { 2886 struct tcp_cookie_transactions ctd; 2887 struct tcp_cookie_values *cvp = tp->cookie_values; 2888 2889 if (get_user(len, optlen)) 2890 return -EFAULT; 2891 if (len < sizeof(ctd)) 2892 return -EINVAL; 2893 2894 memset(&ctd, 0, sizeof(ctd)); 2895 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ? 2896 TCP_COOKIE_IN_ALWAYS : 0) 2897 | (tp->rx_opt.cookie_out_never ? 2898 TCP_COOKIE_OUT_NEVER : 0); 2899 2900 if (cvp != NULL) { 2901 ctd.tcpct_flags |= (cvp->s_data_in ? 2902 TCP_S_DATA_IN : 0) 2903 | (cvp->s_data_out ? 2904 TCP_S_DATA_OUT : 0); 2905 2906 ctd.tcpct_cookie_desired = cvp->cookie_desired; 2907 ctd.tcpct_s_data_desired = cvp->s_data_desired; 2908 2909 memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0], 2910 cvp->cookie_pair_size); 2911 ctd.tcpct_used = cvp->cookie_pair_size; 2912 } 2913 2914 if (put_user(sizeof(ctd), optlen)) 2915 return -EFAULT; 2916 if (copy_to_user(optval, &ctd, sizeof(ctd))) 2917 return -EFAULT; 2918 return 0; 2919 } 2920 case TCP_THIN_LINEAR_TIMEOUTS: 2921 val = tp->thin_lto; 2922 break; 2923 case TCP_THIN_DUPACK: 2924 val = tp->thin_dupack; 2925 break; 2926 2927 case TCP_REPAIR: 2928 val = tp->repair; 2929 break; 2930 2931 case TCP_REPAIR_QUEUE: 2932 if (tp->repair) 2933 val = tp->repair_queue; 2934 else 2935 return -EINVAL; 2936 break; 2937 2938 case TCP_QUEUE_SEQ: 2939 if (tp->repair_queue == TCP_SEND_QUEUE) 2940 val = tp->write_seq; 2941 else if (tp->repair_queue == TCP_RECV_QUEUE) 2942 val = tp->rcv_nxt; 2943 else 2944 return -EINVAL; 2945 break; 2946 2947 case TCP_USER_TIMEOUT: 2948 val = jiffies_to_msecs(icsk->icsk_user_timeout); 2949 break; 2950 default: 2951 return -ENOPROTOOPT; 2952 } 2953 2954 if (put_user(len, optlen)) 2955 return -EFAULT; 2956 if (copy_to_user(optval, &val, len)) 2957 return -EFAULT; 2958 return 0; 2959 } 2960 2961 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 2962 int __user *optlen) 2963 { 2964 struct inet_connection_sock *icsk = inet_csk(sk); 2965 2966 if (level != SOL_TCP) 2967 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 2968 optval, optlen); 2969 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2970 } 2971 EXPORT_SYMBOL(tcp_getsockopt); 2972 2973 #ifdef CONFIG_COMPAT 2974 int compat_tcp_getsockopt(struct sock *sk, int level, int optname, 2975 char __user *optval, int __user *optlen) 2976 { 2977 if (level != SOL_TCP) 2978 return inet_csk_compat_getsockopt(sk, level, optname, 2979 optval, optlen); 2980 return do_tcp_getsockopt(sk, level, optname, optval, optlen); 2981 } 2982 EXPORT_SYMBOL(compat_tcp_getsockopt); 2983 #endif 2984 2985 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, 2986 netdev_features_t features) 2987 { 2988 struct sk_buff *segs = ERR_PTR(-EINVAL); 2989 struct tcphdr *th; 2990 unsigned int thlen; 2991 unsigned int seq; 2992 __be32 delta; 2993 unsigned int oldlen; 2994 unsigned int mss; 2995 2996 if (!pskb_may_pull(skb, sizeof(*th))) 2997 goto out; 2998 2999 th = tcp_hdr(skb); 3000 thlen = th->doff * 4; 3001 if (thlen < sizeof(*th)) 3002 goto out; 3003 3004 if (!pskb_may_pull(skb, thlen)) 3005 goto out; 3006 3007 oldlen = (u16)~skb->len; 3008 __skb_pull(skb, thlen); 3009 3010 mss = skb_shinfo(skb)->gso_size; 3011 if (unlikely(skb->len <= mss)) 3012 goto out; 3013 3014 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 3015 /* Packet is from an untrusted source, reset gso_segs. */ 3016 int type = skb_shinfo(skb)->gso_type; 3017 3018 if (unlikely(type & 3019 ~(SKB_GSO_TCPV4 | 3020 SKB_GSO_DODGY | 3021 SKB_GSO_TCP_ECN | 3022 SKB_GSO_TCPV6 | 3023 0) || 3024 !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))) 3025 goto out; 3026 3027 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); 3028 3029 segs = NULL; 3030 goto out; 3031 } 3032 3033 segs = skb_segment(skb, features); 3034 if (IS_ERR(segs)) 3035 goto out; 3036 3037 delta = htonl(oldlen + (thlen + mss)); 3038 3039 skb = segs; 3040 th = tcp_hdr(skb); 3041 seq = ntohl(th->seq); 3042 3043 do { 3044 th->fin = th->psh = 0; 3045 3046 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 3047 (__force u32)delta)); 3048 if (skb->ip_summed != CHECKSUM_PARTIAL) 3049 th->check = 3050 csum_fold(csum_partial(skb_transport_header(skb), 3051 thlen, skb->csum)); 3052 3053 seq += mss; 3054 skb = skb->next; 3055 th = tcp_hdr(skb); 3056 3057 th->seq = htonl(seq); 3058 th->cwr = 0; 3059 } while (skb->next); 3060 3061 delta = htonl(oldlen + (skb->tail - skb->transport_header) + 3062 skb->data_len); 3063 th->check = ~csum_fold((__force __wsum)((__force u32)th->check + 3064 (__force u32)delta)); 3065 if (skb->ip_summed != CHECKSUM_PARTIAL) 3066 th->check = csum_fold(csum_partial(skb_transport_header(skb), 3067 thlen, skb->csum)); 3068 3069 out: 3070 return segs; 3071 } 3072 EXPORT_SYMBOL(tcp_tso_segment); 3073 3074 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) 3075 { 3076 struct sk_buff **pp = NULL; 3077 struct sk_buff *p; 3078 struct tcphdr *th; 3079 struct tcphdr *th2; 3080 unsigned int len; 3081 unsigned int thlen; 3082 __be32 flags; 3083 unsigned int mss = 1; 3084 unsigned int hlen; 3085 unsigned int off; 3086 int flush = 1; 3087 int i; 3088 3089 off = skb_gro_offset(skb); 3090 hlen = off + sizeof(*th); 3091 th = skb_gro_header_fast(skb, off); 3092 if (skb_gro_header_hard(skb, hlen)) { 3093 th = skb_gro_header_slow(skb, hlen, off); 3094 if (unlikely(!th)) 3095 goto out; 3096 } 3097 3098 thlen = th->doff * 4; 3099 if (thlen < sizeof(*th)) 3100 goto out; 3101 3102 hlen = off + thlen; 3103 if (skb_gro_header_hard(skb, hlen)) { 3104 th = skb_gro_header_slow(skb, hlen, off); 3105 if (unlikely(!th)) 3106 goto out; 3107 } 3108 3109 skb_gro_pull(skb, thlen); 3110 3111 len = skb_gro_len(skb); 3112 flags = tcp_flag_word(th); 3113 3114 for (; (p = *head); head = &p->next) { 3115 if (!NAPI_GRO_CB(p)->same_flow) 3116 continue; 3117 3118 th2 = tcp_hdr(p); 3119 3120 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) { 3121 NAPI_GRO_CB(p)->same_flow = 0; 3122 continue; 3123 } 3124 3125 goto found; 3126 } 3127 3128 goto out_check_final; 3129 3130 found: 3131 flush = NAPI_GRO_CB(p)->flush; 3132 flush |= (__force int)(flags & TCP_FLAG_CWR); 3133 flush |= (__force int)((flags ^ tcp_flag_word(th2)) & 3134 ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); 3135 flush |= (__force int)(th->ack_seq ^ th2->ack_seq); 3136 for (i = sizeof(*th); i < thlen; i += 4) 3137 flush |= *(u32 *)((u8 *)th + i) ^ 3138 *(u32 *)((u8 *)th2 + i); 3139 3140 mss = skb_shinfo(p)->gso_size; 3141 3142 flush |= (len - 1) >= mss; 3143 flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); 3144 3145 if (flush || skb_gro_receive(head, skb)) { 3146 mss = 1; 3147 goto out_check_final; 3148 } 3149 3150 p = *head; 3151 th2 = tcp_hdr(p); 3152 tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); 3153 3154 out_check_final: 3155 flush = len < mss; 3156 flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH | 3157 TCP_FLAG_RST | TCP_FLAG_SYN | 3158 TCP_FLAG_FIN)); 3159 3160 if (p && (!NAPI_GRO_CB(skb)->same_flow || flush)) 3161 pp = head; 3162 3163 out: 3164 NAPI_GRO_CB(skb)->flush |= flush; 3165 3166 return pp; 3167 } 3168 EXPORT_SYMBOL(tcp_gro_receive); 3169 3170 int tcp_gro_complete(struct sk_buff *skb) 3171 { 3172 struct tcphdr *th = tcp_hdr(skb); 3173 3174 skb->csum_start = skb_transport_header(skb) - skb->head; 3175 skb->csum_offset = offsetof(struct tcphdr, check); 3176 skb->ip_summed = CHECKSUM_PARTIAL; 3177 3178 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count; 3179 3180 if (th->cwr) 3181 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; 3182 3183 return 0; 3184 } 3185 EXPORT_SYMBOL(tcp_gro_complete); 3186 3187 #ifdef CONFIG_TCP_MD5SIG 3188 static unsigned long tcp_md5sig_users; 3189 static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool; 3190 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock); 3191 3192 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool) 3193 { 3194 int cpu; 3195 3196 for_each_possible_cpu(cpu) { 3197 struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu); 3198 3199 if (p->md5_desc.tfm) 3200 crypto_free_hash(p->md5_desc.tfm); 3201 } 3202 free_percpu(pool); 3203 } 3204 3205 void tcp_free_md5sig_pool(void) 3206 { 3207 struct tcp_md5sig_pool __percpu *pool = NULL; 3208 3209 spin_lock_bh(&tcp_md5sig_pool_lock); 3210 if (--tcp_md5sig_users == 0) { 3211 pool = tcp_md5sig_pool; 3212 tcp_md5sig_pool = NULL; 3213 } 3214 spin_unlock_bh(&tcp_md5sig_pool_lock); 3215 if (pool) 3216 __tcp_free_md5sig_pool(pool); 3217 } 3218 EXPORT_SYMBOL(tcp_free_md5sig_pool); 3219 3220 static struct tcp_md5sig_pool __percpu * 3221 __tcp_alloc_md5sig_pool(struct sock *sk) 3222 { 3223 int cpu; 3224 struct tcp_md5sig_pool __percpu *pool; 3225 3226 pool = alloc_percpu(struct tcp_md5sig_pool); 3227 if (!pool) 3228 return NULL; 3229 3230 for_each_possible_cpu(cpu) { 3231 struct crypto_hash *hash; 3232 3233 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 3234 if (!hash || IS_ERR(hash)) 3235 goto out_free; 3236 3237 per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash; 3238 } 3239 return pool; 3240 out_free: 3241 __tcp_free_md5sig_pool(pool); 3242 return NULL; 3243 } 3244 3245 struct tcp_md5sig_pool __percpu *tcp_alloc_md5sig_pool(struct sock *sk) 3246 { 3247 struct tcp_md5sig_pool __percpu *pool; 3248 bool alloc = false; 3249 3250 retry: 3251 spin_lock_bh(&tcp_md5sig_pool_lock); 3252 pool = tcp_md5sig_pool; 3253 if (tcp_md5sig_users++ == 0) { 3254 alloc = true; 3255 spin_unlock_bh(&tcp_md5sig_pool_lock); 3256 } else if (!pool) { 3257 tcp_md5sig_users--; 3258 spin_unlock_bh(&tcp_md5sig_pool_lock); 3259 cpu_relax(); 3260 goto retry; 3261 } else 3262 spin_unlock_bh(&tcp_md5sig_pool_lock); 3263 3264 if (alloc) { 3265 /* we cannot hold spinlock here because this may sleep. */ 3266 struct tcp_md5sig_pool __percpu *p; 3267 3268 p = __tcp_alloc_md5sig_pool(sk); 3269 spin_lock_bh(&tcp_md5sig_pool_lock); 3270 if (!p) { 3271 tcp_md5sig_users--; 3272 spin_unlock_bh(&tcp_md5sig_pool_lock); 3273 return NULL; 3274 } 3275 pool = tcp_md5sig_pool; 3276 if (pool) { 3277 /* oops, it has already been assigned. */ 3278 spin_unlock_bh(&tcp_md5sig_pool_lock); 3279 __tcp_free_md5sig_pool(p); 3280 } else { 3281 tcp_md5sig_pool = pool = p; 3282 spin_unlock_bh(&tcp_md5sig_pool_lock); 3283 } 3284 } 3285 return pool; 3286 } 3287 EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 3288 3289 3290 /** 3291 * tcp_get_md5sig_pool - get md5sig_pool for this user 3292 * 3293 * We use percpu structure, so if we succeed, we exit with preemption 3294 * and BH disabled, to make sure another thread or softirq handling 3295 * wont try to get same context. 3296 */ 3297 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) 3298 { 3299 struct tcp_md5sig_pool __percpu *p; 3300 3301 local_bh_disable(); 3302 3303 spin_lock(&tcp_md5sig_pool_lock); 3304 p = tcp_md5sig_pool; 3305 if (p) 3306 tcp_md5sig_users++; 3307 spin_unlock(&tcp_md5sig_pool_lock); 3308 3309 if (p) 3310 return this_cpu_ptr(p); 3311 3312 local_bh_enable(); 3313 return NULL; 3314 } 3315 EXPORT_SYMBOL(tcp_get_md5sig_pool); 3316 3317 void tcp_put_md5sig_pool(void) 3318 { 3319 local_bh_enable(); 3320 tcp_free_md5sig_pool(); 3321 } 3322 EXPORT_SYMBOL(tcp_put_md5sig_pool); 3323 3324 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp, 3325 const struct tcphdr *th) 3326 { 3327 struct scatterlist sg; 3328 struct tcphdr hdr; 3329 int err; 3330 3331 /* We are not allowed to change tcphdr, make a local copy */ 3332 memcpy(&hdr, th, sizeof(hdr)); 3333 hdr.check = 0; 3334 3335 /* options aren't included in the hash */ 3336 sg_init_one(&sg, &hdr, sizeof(hdr)); 3337 err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr)); 3338 return err; 3339 } 3340 EXPORT_SYMBOL(tcp_md5_hash_header); 3341 3342 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, 3343 const struct sk_buff *skb, unsigned int header_len) 3344 { 3345 struct scatterlist sg; 3346 const struct tcphdr *tp = tcp_hdr(skb); 3347 struct hash_desc *desc = &hp->md5_desc; 3348 unsigned int i; 3349 const unsigned int head_data_len = skb_headlen(skb) > header_len ? 3350 skb_headlen(skb) - header_len : 0; 3351 const struct skb_shared_info *shi = skb_shinfo(skb); 3352 struct sk_buff *frag_iter; 3353 3354 sg_init_table(&sg, 1); 3355 3356 sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len); 3357 if (crypto_hash_update(desc, &sg, head_data_len)) 3358 return 1; 3359 3360 for (i = 0; i < shi->nr_frags; ++i) { 3361 const struct skb_frag_struct *f = &shi->frags[i]; 3362 struct page *page = skb_frag_page(f); 3363 sg_set_page(&sg, page, skb_frag_size(f), f->page_offset); 3364 if (crypto_hash_update(desc, &sg, skb_frag_size(f))) 3365 return 1; 3366 } 3367 3368 skb_walk_frags(skb, frag_iter) 3369 if (tcp_md5_hash_skb_data(hp, frag_iter, 0)) 3370 return 1; 3371 3372 return 0; 3373 } 3374 EXPORT_SYMBOL(tcp_md5_hash_skb_data); 3375 3376 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key) 3377 { 3378 struct scatterlist sg; 3379 3380 sg_init_one(&sg, key->key, key->keylen); 3381 return crypto_hash_update(&hp->md5_desc, &sg, key->keylen); 3382 } 3383 EXPORT_SYMBOL(tcp_md5_hash_key); 3384 3385 #endif 3386 3387 /* Each Responder maintains up to two secret values concurrently for 3388 * efficient secret rollover. Each secret value has 4 states: 3389 * 3390 * Generating. (tcp_secret_generating != tcp_secret_primary) 3391 * Generates new Responder-Cookies, but not yet used for primary 3392 * verification. This is a short-term state, typically lasting only 3393 * one round trip time (RTT). 3394 * 3395 * Primary. (tcp_secret_generating == tcp_secret_primary) 3396 * Used both for generation and primary verification. 3397 * 3398 * Retiring. (tcp_secret_retiring != tcp_secret_secondary) 3399 * Used for verification, until the first failure that can be 3400 * verified by the newer Generating secret. At that time, this 3401 * cookie's state is changed to Secondary, and the Generating 3402 * cookie's state is changed to Primary. This is a short-term state, 3403 * typically lasting only one round trip time (RTT). 3404 * 3405 * Secondary. (tcp_secret_retiring == tcp_secret_secondary) 3406 * Used for secondary verification, after primary verification 3407 * failures. This state lasts no more than twice the Maximum Segment 3408 * Lifetime (2MSL). Then, the secret is discarded. 3409 */ 3410 struct tcp_cookie_secret { 3411 /* The secret is divided into two parts. The digest part is the 3412 * equivalent of previously hashing a secret and saving the state, 3413 * and serves as an initialization vector (IV). The message part 3414 * serves as the trailing secret. 3415 */ 3416 u32 secrets[COOKIE_WORKSPACE_WORDS]; 3417 unsigned long expires; 3418 }; 3419 3420 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL) 3421 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2) 3422 #define TCP_SECRET_LIFE (HZ * 600) 3423 3424 static struct tcp_cookie_secret tcp_secret_one; 3425 static struct tcp_cookie_secret tcp_secret_two; 3426 3427 /* Essentially a circular list, without dynamic allocation. */ 3428 static struct tcp_cookie_secret *tcp_secret_generating; 3429 static struct tcp_cookie_secret *tcp_secret_primary; 3430 static struct tcp_cookie_secret *tcp_secret_retiring; 3431 static struct tcp_cookie_secret *tcp_secret_secondary; 3432 3433 static DEFINE_SPINLOCK(tcp_secret_locker); 3434 3435 /* Select a pseudo-random word in the cookie workspace. 3436 */ 3437 static inline u32 tcp_cookie_work(const u32 *ws, const int n) 3438 { 3439 return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])]; 3440 } 3441 3442 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed. 3443 * Called in softirq context. 3444 * Returns: 0 for success. 3445 */ 3446 int tcp_cookie_generator(u32 *bakery) 3447 { 3448 unsigned long jiffy = jiffies; 3449 3450 if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) { 3451 spin_lock_bh(&tcp_secret_locker); 3452 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) { 3453 /* refreshed by another */ 3454 memcpy(bakery, 3455 &tcp_secret_generating->secrets[0], 3456 COOKIE_WORKSPACE_WORDS); 3457 } else { 3458 /* still needs refreshing */ 3459 get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS); 3460 3461 /* The first time, paranoia assumes that the 3462 * randomization function isn't as strong. But, 3463 * this secret initialization is delayed until 3464 * the last possible moment (packet arrival). 3465 * Although that time is observable, it is 3466 * unpredictably variable. Mash in the most 3467 * volatile clock bits available, and expire the 3468 * secret extra quickly. 3469 */ 3470 if (unlikely(tcp_secret_primary->expires == 3471 tcp_secret_secondary->expires)) { 3472 struct timespec tv; 3473 3474 getnstimeofday(&tv); 3475 bakery[COOKIE_DIGEST_WORDS+0] ^= 3476 (u32)tv.tv_nsec; 3477 3478 tcp_secret_secondary->expires = jiffy 3479 + TCP_SECRET_1MSL 3480 + (0x0f & tcp_cookie_work(bakery, 0)); 3481 } else { 3482 tcp_secret_secondary->expires = jiffy 3483 + TCP_SECRET_LIFE 3484 + (0xff & tcp_cookie_work(bakery, 1)); 3485 tcp_secret_primary->expires = jiffy 3486 + TCP_SECRET_2MSL 3487 + (0x1f & tcp_cookie_work(bakery, 2)); 3488 } 3489 memcpy(&tcp_secret_secondary->secrets[0], 3490 bakery, COOKIE_WORKSPACE_WORDS); 3491 3492 rcu_assign_pointer(tcp_secret_generating, 3493 tcp_secret_secondary); 3494 rcu_assign_pointer(tcp_secret_retiring, 3495 tcp_secret_primary); 3496 /* 3497 * Neither call_rcu() nor synchronize_rcu() needed. 3498 * Retiring data is not freed. It is replaced after 3499 * further (locked) pointer updates, and a quiet time 3500 * (minimum 1MSL, maximum LIFE - 2MSL). 3501 */ 3502 } 3503 spin_unlock_bh(&tcp_secret_locker); 3504 } else { 3505 rcu_read_lock_bh(); 3506 memcpy(bakery, 3507 &rcu_dereference(tcp_secret_generating)->secrets[0], 3508 COOKIE_WORKSPACE_WORDS); 3509 rcu_read_unlock_bh(); 3510 } 3511 return 0; 3512 } 3513 EXPORT_SYMBOL(tcp_cookie_generator); 3514 3515 void tcp_done(struct sock *sk) 3516 { 3517 struct request_sock *req = tcp_sk(sk)->fastopen_rsk; 3518 3519 if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 3520 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS); 3521 3522 tcp_set_state(sk, TCP_CLOSE); 3523 tcp_clear_xmit_timers(sk); 3524 if (req != NULL) 3525 reqsk_fastopen_remove(sk, req, false); 3526 3527 sk->sk_shutdown = SHUTDOWN_MASK; 3528 3529 if (!sock_flag(sk, SOCK_DEAD)) 3530 sk->sk_state_change(sk); 3531 else 3532 inet_csk_destroy_sock(sk); 3533 } 3534 EXPORT_SYMBOL_GPL(tcp_done); 3535 3536 extern struct tcp_congestion_ops tcp_reno; 3537 3538 static __initdata unsigned long thash_entries; 3539 static int __init set_thash_entries(char *str) 3540 { 3541 ssize_t ret; 3542 3543 if (!str) 3544 return 0; 3545 3546 ret = kstrtoul(str, 0, &thash_entries); 3547 if (ret) 3548 return 0; 3549 3550 return 1; 3551 } 3552 __setup("thash_entries=", set_thash_entries); 3553 3554 void tcp_init_mem(struct net *net) 3555 { 3556 unsigned long limit = nr_free_buffer_pages() / 8; 3557 limit = max(limit, 128UL); 3558 net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3; 3559 net->ipv4.sysctl_tcp_mem[1] = limit; 3560 net->ipv4.sysctl_tcp_mem[2] = net->ipv4.sysctl_tcp_mem[0] * 2; 3561 } 3562 3563 void __init tcp_init(void) 3564 { 3565 struct sk_buff *skb = NULL; 3566 unsigned long limit; 3567 int max_rshare, max_wshare, cnt; 3568 unsigned int i; 3569 unsigned long jiffy = jiffies; 3570 3571 BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb)); 3572 3573 percpu_counter_init(&tcp_sockets_allocated, 0); 3574 percpu_counter_init(&tcp_orphan_count, 0); 3575 tcp_hashinfo.bind_bucket_cachep = 3576 kmem_cache_create("tcp_bind_bucket", 3577 sizeof(struct inet_bind_bucket), 0, 3578 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 3579 3580 /* Size and allocate the main established and bind bucket 3581 * hash tables. 3582 * 3583 * The methodology is similar to that of the buffer cache. 3584 */ 3585 tcp_hashinfo.ehash = 3586 alloc_large_system_hash("TCP established", 3587 sizeof(struct inet_ehash_bucket), 3588 thash_entries, 3589 (totalram_pages >= 128 * 1024) ? 3590 13 : 15, 3591 0, 3592 NULL, 3593 &tcp_hashinfo.ehash_mask, 3594 0, 3595 thash_entries ? 0 : 512 * 1024); 3596 for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) { 3597 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i); 3598 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i); 3599 } 3600 if (inet_ehash_locks_alloc(&tcp_hashinfo)) 3601 panic("TCP: failed to alloc ehash_locks"); 3602 tcp_hashinfo.bhash = 3603 alloc_large_system_hash("TCP bind", 3604 sizeof(struct inet_bind_hashbucket), 3605 tcp_hashinfo.ehash_mask + 1, 3606 (totalram_pages >= 128 * 1024) ? 3607 13 : 15, 3608 0, 3609 &tcp_hashinfo.bhash_size, 3610 NULL, 3611 0, 3612 64 * 1024); 3613 tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size; 3614 for (i = 0; i < tcp_hashinfo.bhash_size; i++) { 3615 spin_lock_init(&tcp_hashinfo.bhash[i].lock); 3616 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain); 3617 } 3618 3619 3620 cnt = tcp_hashinfo.ehash_mask + 1; 3621 3622 tcp_death_row.sysctl_max_tw_buckets = cnt / 2; 3623 sysctl_tcp_max_orphans = cnt / 2; 3624 sysctl_max_syn_backlog = max(128, cnt / 256); 3625 3626 tcp_init_mem(&init_net); 3627 /* Set per-socket limits to no more than 1/128 the pressure threshold */ 3628 limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7); 3629 max_wshare = min(4UL*1024*1024, limit); 3630 max_rshare = min(6UL*1024*1024, limit); 3631 3632 sysctl_tcp_wmem[0] = SK_MEM_QUANTUM; 3633 sysctl_tcp_wmem[1] = 16*1024; 3634 sysctl_tcp_wmem[2] = max(64*1024, max_wshare); 3635 3636 sysctl_tcp_rmem[0] = SK_MEM_QUANTUM; 3637 sysctl_tcp_rmem[1] = 87380; 3638 sysctl_tcp_rmem[2] = max(87380, max_rshare); 3639 3640 pr_info("Hash tables configured (established %u bind %u)\n", 3641 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size); 3642 3643 tcp_metrics_init(); 3644 3645 tcp_register_congestion_control(&tcp_reno); 3646 3647 memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets)); 3648 memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets)); 3649 tcp_secret_one.expires = jiffy; /* past due */ 3650 tcp_secret_two.expires = jiffy; /* past due */ 3651 tcp_secret_generating = &tcp_secret_one; 3652 tcp_secret_primary = &tcp_secret_one; 3653 tcp_secret_retiring = &tcp_secret_two; 3654 tcp_secret_secondary = &tcp_secret_two; 3655 tcp_tasklet_init(); 3656 } 3657