1 /* $NetBSD: tcp_input.c,v 1.295 2009/03/18 16:00:22 cegger Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * @(#)COPYRIGHT 1.1 (NRL) 17 January 1995 34 * 35 * NRL grants permission for redistribution and use in source and binary 36 * forms, with or without modification, of the software and documentation 37 * created at NRL provided that the following conditions are met: 38 * 39 * 1. Redistributions of source code must retain the above copyright 40 * notice, this list of conditions and the following disclaimer. 41 * 2. Redistributions in binary form must reproduce the above copyright 42 * notice, this list of conditions and the following disclaimer in the 43 * documentation and/or other materials provided with the distribution. 44 * 3. All advertising materials mentioning features or use of this software 45 * must display the following acknowledgements: 46 * This product includes software developed by the University of 47 * California, Berkeley and its contributors. 48 * This product includes software developed at the Information 49 * Technology Division, US Naval Research Laboratory. 50 * 4. Neither the name of the NRL nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL AND CONTRIBUTORS ``AS 55 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 56 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 57 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NRL OR 58 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 59 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 60 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 61 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 62 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 63 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 64 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 65 * 66 * The views and conclusions contained in the software and documentation 67 * are those of the authors and should not be interpreted as representing 68 * official policies, either expressed or implied, of the US Naval 69 * Research Laboratory (NRL). 70 */ 71 72 /*- 73 * Copyright (c) 1997, 1998, 1999, 2001, 2005, 2006 The NetBSD Foundation, Inc. 74 * All rights reserved. 75 * 76 * This code is derived from software contributed to The NetBSD Foundation 77 * by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation 78 * Facility, NASA Ames Research Center. 79 * This code is derived from software contributed to The NetBSD Foundation 80 * by Charles M. Hannum. 81 * This code is derived from software contributed to The NetBSD Foundation 82 * by Rui Paulo. 83 * 84 * Redistribution and use in source and binary forms, with or without 85 * modification, are permitted provided that the following conditions 86 * are met: 87 * 1. Redistributions of source code must retain the above copyright 88 * notice, this list of conditions and the following disclaimer. 89 * 2. Redistributions in binary form must reproduce the above copyright 90 * notice, this list of conditions and the following disclaimer in the 91 * documentation and/or other materials provided with the distribution. 92 * 93 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 94 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 95 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 96 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 97 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 98 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 99 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 100 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 101 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 103 * POSSIBILITY OF SUCH DAMAGE. 104 */ 105 106 /* 107 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995 108 * The Regents of the University of California. All rights reserved. 109 * 110 * Redistribution and use in source and binary forms, with or without 111 * modification, are permitted provided that the following conditions 112 * are met: 113 * 1. Redistributions of source code must retain the above copyright 114 * notice, this list of conditions and the following disclaimer. 115 * 2. Redistributions in binary form must reproduce the above copyright 116 * notice, this list of conditions and the following disclaimer in the 117 * documentation and/or other materials provided with the distribution. 118 * 3. Neither the name of the University nor the names of its contributors 119 * may be used to endorse or promote products derived from this software 120 * without specific prior written permission. 121 * 122 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 123 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 124 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 125 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 126 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 127 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 128 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 129 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 130 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 131 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 132 * SUCH DAMAGE. 133 * 134 * @(#)tcp_input.c 8.12 (Berkeley) 5/24/95 135 */ 136 137 /* 138 * TODO list for SYN cache stuff: 139 * 140 * Find room for a "state" field, which is needed to keep a 141 * compressed state for TIME_WAIT TCBs. It's been noted already 142 * that this is fairly important for very high-volume web and 143 * mail servers, which use a large number of short-lived 144 * connections. 145 */ 146 147 #include <sys/cdefs.h> 148 __KERNEL_RCSID(0, "$NetBSD: tcp_input.c,v 1.295 2009/03/18 16:00:22 cegger Exp $"); 149 150 #include "opt_inet.h" 151 #include "opt_ipsec.h" 152 #include "opt_inet_csum.h" 153 #include "opt_tcp_debug.h" 154 155 #include <sys/param.h> 156 #include <sys/systm.h> 157 #include <sys/malloc.h> 158 #include <sys/mbuf.h> 159 #include <sys/protosw.h> 160 #include <sys/socket.h> 161 #include <sys/socketvar.h> 162 #include <sys/errno.h> 163 #include <sys/syslog.h> 164 #include <sys/pool.h> 165 #include <sys/domain.h> 166 #include <sys/kernel.h> 167 #ifdef TCP_SIGNATURE 168 #include <sys/md5.h> 169 #endif 170 #include <sys/lwp.h> /* for lwp0 */ 171 172 #include <net/if.h> 173 #include <net/route.h> 174 #include <net/if_types.h> 175 176 #include <netinet/in.h> 177 #include <netinet/in_systm.h> 178 #include <netinet/ip.h> 179 #include <netinet/in_pcb.h> 180 #include <netinet/in_var.h> 181 #include <netinet/ip_var.h> 182 #include <netinet/in_offload.h> 183 184 #ifdef INET6 185 #ifndef INET 186 #include <netinet/in.h> 187 #endif 188 #include <netinet/ip6.h> 189 #include <netinet6/ip6_var.h> 190 #include <netinet6/in6_pcb.h> 191 #include <netinet6/ip6_var.h> 192 #include <netinet6/in6_var.h> 193 #include <netinet/icmp6.h> 194 #include <netinet6/nd6.h> 195 #ifdef TCP_SIGNATURE 196 #include <netinet6/scope6_var.h> 197 #endif 198 #endif 199 200 #ifndef INET6 201 /* always need ip6.h for IP6_EXTHDR_GET */ 202 #include <netinet/ip6.h> 203 #endif 204 205 #include <netinet/tcp.h> 206 #include <netinet/tcp_fsm.h> 207 #include <netinet/tcp_seq.h> 208 #include <netinet/tcp_timer.h> 209 #include <netinet/tcp_var.h> 210 #include <netinet/tcp_private.h> 211 #include <netinet/tcpip.h> 212 #include <netinet/tcp_congctl.h> 213 #include <netinet/tcp_debug.h> 214 215 #include <machine/stdarg.h> 216 217 #ifdef IPSEC 218 #include <netinet6/ipsec.h> 219 #include <netinet6/ipsec_private.h> 220 #include <netkey/key.h> 221 #endif /*IPSEC*/ 222 #ifdef INET6 223 #include "faith.h" 224 #if defined(NFAITH) && NFAITH > 0 225 #include <net/if_faith.h> 226 #endif 227 #endif /* IPSEC */ 228 229 #ifdef FAST_IPSEC 230 #include <netipsec/ipsec.h> 231 #include <netipsec/ipsec_var.h> 232 #include <netipsec/ipsec_private.h> 233 #include <netipsec/key.h> 234 #ifdef INET6 235 #include <netipsec/ipsec6.h> 236 #endif 237 #endif /* FAST_IPSEC*/ 238 239 int tcprexmtthresh = 3; 240 int tcp_log_refused; 241 242 int tcp_do_autorcvbuf = 0; 243 int tcp_autorcvbuf_inc = 16 * 1024; 244 int tcp_autorcvbuf_max = 256 * 1024; 245 246 static int tcp_rst_ppslim_count = 0; 247 static struct timeval tcp_rst_ppslim_last; 248 static int tcp_ackdrop_ppslim_count = 0; 249 static struct timeval tcp_ackdrop_ppslim_last; 250 251 #define TCP_PAWS_IDLE (24U * 24 * 60 * 60 * PR_SLOWHZ) 252 253 /* for modulo comparisons of timestamps */ 254 #define TSTMP_LT(a,b) ((int)((a)-(b)) < 0) 255 #define TSTMP_GEQ(a,b) ((int)((a)-(b)) >= 0) 256 257 /* 258 * Neighbor Discovery, Neighbor Unreachability Detection Upper layer hint. 259 */ 260 #ifdef INET6 261 static inline void 262 nd6_hint(struct tcpcb *tp) 263 { 264 struct rtentry *rt; 265 266 if (tp != NULL && tp->t_in6pcb != NULL && tp->t_family == AF_INET6 && 267 (rt = rtcache_validate(&tp->t_in6pcb->in6p_route)) != NULL) 268 nd6_nud_hint(rt, NULL, 0); 269 } 270 #else 271 static inline void 272 nd6_hint(struct tcpcb *tp) 273 { 274 } 275 #endif 276 277 /* 278 * Compute ACK transmission behavior. Delay the ACK unless 279 * we have already delayed an ACK (must send an ACK every two segments). 280 * We also ACK immediately if we received a PUSH and the ACK-on-PUSH 281 * option is enabled. 282 */ 283 static void 284 tcp_setup_ack(struct tcpcb *tp, const struct tcphdr *th) 285 { 286 287 if (tp->t_flags & TF_DELACK || 288 (tcp_ack_on_push && th->th_flags & TH_PUSH)) 289 tp->t_flags |= TF_ACKNOW; 290 else 291 TCP_SET_DELACK(tp); 292 } 293 294 static void 295 icmp_check(struct tcpcb *tp, const struct tcphdr *th, int acked) 296 { 297 298 /* 299 * If we had a pending ICMP message that refers to data that have 300 * just been acknowledged, disregard the recorded ICMP message. 301 */ 302 if ((tp->t_flags & TF_PMTUD_PEND) && 303 SEQ_GT(th->th_ack, tp->t_pmtud_th_seq)) 304 tp->t_flags &= ~TF_PMTUD_PEND; 305 306 /* 307 * Keep track of the largest chunk of data 308 * acknowledged since last PMTU update 309 */ 310 if (tp->t_pmtud_mss_acked < acked) 311 tp->t_pmtud_mss_acked = acked; 312 } 313 314 /* 315 * Convert TCP protocol fields to host order for easier processing. 316 */ 317 static void 318 tcp_fields_to_host(struct tcphdr *th) 319 { 320 321 NTOHL(th->th_seq); 322 NTOHL(th->th_ack); 323 NTOHS(th->th_win); 324 NTOHS(th->th_urp); 325 } 326 327 /* 328 * ... and reverse the above. 329 */ 330 static void 331 tcp_fields_to_net(struct tcphdr *th) 332 { 333 334 HTONL(th->th_seq); 335 HTONL(th->th_ack); 336 HTONS(th->th_win); 337 HTONS(th->th_urp); 338 } 339 340 #ifdef TCP_CSUM_COUNTERS 341 #include <sys/device.h> 342 343 #if defined(INET) 344 extern struct evcnt tcp_hwcsum_ok; 345 extern struct evcnt tcp_hwcsum_bad; 346 extern struct evcnt tcp_hwcsum_data; 347 extern struct evcnt tcp_swcsum; 348 #endif /* defined(INET) */ 349 #if defined(INET6) 350 extern struct evcnt tcp6_hwcsum_ok; 351 extern struct evcnt tcp6_hwcsum_bad; 352 extern struct evcnt tcp6_hwcsum_data; 353 extern struct evcnt tcp6_swcsum; 354 #endif /* defined(INET6) */ 355 356 #define TCP_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 357 358 #else 359 360 #define TCP_CSUM_COUNTER_INCR(ev) /* nothing */ 361 362 #endif /* TCP_CSUM_COUNTERS */ 363 364 #ifdef TCP_REASS_COUNTERS 365 #include <sys/device.h> 366 367 extern struct evcnt tcp_reass_; 368 extern struct evcnt tcp_reass_empty; 369 extern struct evcnt tcp_reass_iteration[8]; 370 extern struct evcnt tcp_reass_prependfirst; 371 extern struct evcnt tcp_reass_prepend; 372 extern struct evcnt tcp_reass_insert; 373 extern struct evcnt tcp_reass_inserttail; 374 extern struct evcnt tcp_reass_append; 375 extern struct evcnt tcp_reass_appendtail; 376 extern struct evcnt tcp_reass_overlaptail; 377 extern struct evcnt tcp_reass_overlapfront; 378 extern struct evcnt tcp_reass_segdup; 379 extern struct evcnt tcp_reass_fragdup; 380 381 #define TCP_REASS_COUNTER_INCR(ev) (ev)->ev_count++ 382 383 #else 384 385 #define TCP_REASS_COUNTER_INCR(ev) /* nothing */ 386 387 #endif /* TCP_REASS_COUNTERS */ 388 389 static int tcp_reass(struct tcpcb *, const struct tcphdr *, struct mbuf *, 390 int *); 391 static int tcp_dooptions(struct tcpcb *, const u_char *, int, 392 struct tcphdr *, struct mbuf *, int, struct tcp_opt_info *); 393 394 #ifdef INET 395 static void tcp4_log_refused(const struct ip *, const struct tcphdr *); 396 #endif 397 #ifdef INET6 398 static void tcp6_log_refused(const struct ip6_hdr *, const struct tcphdr *); 399 #endif 400 401 #define TRAVERSE(x) while ((x)->m_next) (x) = (x)->m_next 402 403 #if defined(MBUFTRACE) 404 struct mowner tcp_reass_mowner = MOWNER_INIT("tcp", "reass"); 405 #endif /* defined(MBUFTRACE) */ 406 407 static struct pool tcpipqent_pool; 408 409 void 410 tcpipqent_init(void) 411 { 412 413 pool_init(&tcpipqent_pool, sizeof(struct ipqent), 0, 0, 0, "tcpipqepl", 414 NULL, IPL_VM); 415 } 416 417 struct ipqent * 418 tcpipqent_alloc(void) 419 { 420 struct ipqent *ipqe; 421 int s; 422 423 s = splvm(); 424 ipqe = pool_get(&tcpipqent_pool, PR_NOWAIT); 425 splx(s); 426 427 return ipqe; 428 } 429 430 void 431 tcpipqent_free(struct ipqent *ipqe) 432 { 433 int s; 434 435 s = splvm(); 436 pool_put(&tcpipqent_pool, ipqe); 437 splx(s); 438 } 439 440 static int 441 tcp_reass(struct tcpcb *tp, const struct tcphdr *th, struct mbuf *m, int *tlen) 442 { 443 struct ipqent *p, *q, *nq, *tiqe = NULL; 444 struct socket *so = NULL; 445 int pkt_flags; 446 tcp_seq pkt_seq; 447 unsigned pkt_len; 448 u_long rcvpartdupbyte = 0; 449 u_long rcvoobyte; 450 #ifdef TCP_REASS_COUNTERS 451 u_int count = 0; 452 #endif 453 uint64_t *tcps; 454 455 if (tp->t_inpcb) 456 so = tp->t_inpcb->inp_socket; 457 #ifdef INET6 458 else if (tp->t_in6pcb) 459 so = tp->t_in6pcb->in6p_socket; 460 #endif 461 462 TCP_REASS_LOCK_CHECK(tp); 463 464 /* 465 * Call with th==0 after become established to 466 * force pre-ESTABLISHED data up to user socket. 467 */ 468 if (th == 0) 469 goto present; 470 471 m_claimm(m, &tcp_reass_mowner); 472 473 rcvoobyte = *tlen; 474 /* 475 * Copy these to local variables because the tcpiphdr 476 * gets munged while we are collapsing mbufs. 477 */ 478 pkt_seq = th->th_seq; 479 pkt_len = *tlen; 480 pkt_flags = th->th_flags; 481 482 TCP_REASS_COUNTER_INCR(&tcp_reass_); 483 484 if ((p = TAILQ_LAST(&tp->segq, ipqehead)) != NULL) { 485 /* 486 * When we miss a packet, the vast majority of time we get 487 * packets that follow it in order. So optimize for that. 488 */ 489 if (pkt_seq == p->ipqe_seq + p->ipqe_len) { 490 p->ipqe_len += pkt_len; 491 p->ipqe_flags |= pkt_flags; 492 m_cat(p->ipre_mlast, m); 493 TRAVERSE(p->ipre_mlast); 494 m = NULL; 495 tiqe = p; 496 TAILQ_REMOVE(&tp->timeq, p, ipqe_timeq); 497 TCP_REASS_COUNTER_INCR(&tcp_reass_appendtail); 498 goto skip_replacement; 499 } 500 /* 501 * While we're here, if the pkt is completely beyond 502 * anything we have, just insert it at the tail. 503 */ 504 if (SEQ_GT(pkt_seq, p->ipqe_seq + p->ipqe_len)) { 505 TCP_REASS_COUNTER_INCR(&tcp_reass_inserttail); 506 goto insert_it; 507 } 508 } 509 510 q = TAILQ_FIRST(&tp->segq); 511 512 if (q != NULL) { 513 /* 514 * If this segment immediately precedes the first out-of-order 515 * block, simply slap the segment in front of it and (mostly) 516 * skip the complicated logic. 517 */ 518 if (pkt_seq + pkt_len == q->ipqe_seq) { 519 q->ipqe_seq = pkt_seq; 520 q->ipqe_len += pkt_len; 521 q->ipqe_flags |= pkt_flags; 522 m_cat(m, q->ipqe_m); 523 q->ipqe_m = m; 524 q->ipre_mlast = m; /* last mbuf may have changed */ 525 TRAVERSE(q->ipre_mlast); 526 tiqe = q; 527 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 528 TCP_REASS_COUNTER_INCR(&tcp_reass_prependfirst); 529 goto skip_replacement; 530 } 531 } else { 532 TCP_REASS_COUNTER_INCR(&tcp_reass_empty); 533 } 534 535 /* 536 * Find a segment which begins after this one does. 537 */ 538 for (p = NULL; q != NULL; q = nq) { 539 nq = TAILQ_NEXT(q, ipqe_q); 540 #ifdef TCP_REASS_COUNTERS 541 count++; 542 #endif 543 /* 544 * If the received segment is just right after this 545 * fragment, merge the two together and then check 546 * for further overlaps. 547 */ 548 if (q->ipqe_seq + q->ipqe_len == pkt_seq) { 549 #ifdef TCPREASS_DEBUG 550 printf("tcp_reass[%p]: concat %u:%u(%u) to %u:%u(%u)\n", 551 tp, pkt_seq, pkt_seq + pkt_len, pkt_len, 552 q->ipqe_seq, q->ipqe_seq + q->ipqe_len, q->ipqe_len); 553 #endif 554 pkt_len += q->ipqe_len; 555 pkt_flags |= q->ipqe_flags; 556 pkt_seq = q->ipqe_seq; 557 m_cat(q->ipre_mlast, m); 558 TRAVERSE(q->ipre_mlast); 559 m = q->ipqe_m; 560 TCP_REASS_COUNTER_INCR(&tcp_reass_append); 561 goto free_ipqe; 562 } 563 /* 564 * If the received segment is completely past this 565 * fragment, we need to go the next fragment. 566 */ 567 if (SEQ_LT(q->ipqe_seq + q->ipqe_len, pkt_seq)) { 568 p = q; 569 continue; 570 } 571 /* 572 * If the fragment is past the received segment, 573 * it (or any following) can't be concatenated. 574 */ 575 if (SEQ_GT(q->ipqe_seq, pkt_seq + pkt_len)) { 576 TCP_REASS_COUNTER_INCR(&tcp_reass_insert); 577 break; 578 } 579 580 /* 581 * We've received all the data in this segment before. 582 * mark it as a duplicate and return. 583 */ 584 if (SEQ_LEQ(q->ipqe_seq, pkt_seq) && 585 SEQ_GEQ(q->ipqe_seq + q->ipqe_len, pkt_seq + pkt_len)) { 586 tcps = TCP_STAT_GETREF(); 587 tcps[TCP_STAT_RCVDUPPACK]++; 588 tcps[TCP_STAT_RCVDUPBYTE] += pkt_len; 589 TCP_STAT_PUTREF(); 590 tcp_new_dsack(tp, pkt_seq, pkt_len); 591 m_freem(m); 592 if (tiqe != NULL) { 593 tcpipqent_free(tiqe); 594 } 595 TCP_REASS_COUNTER_INCR(&tcp_reass_segdup); 596 return (0); 597 } 598 /* 599 * Received segment completely overlaps this fragment 600 * so we drop the fragment (this keeps the temporal 601 * ordering of segments correct). 602 */ 603 if (SEQ_GEQ(q->ipqe_seq, pkt_seq) && 604 SEQ_LEQ(q->ipqe_seq + q->ipqe_len, pkt_seq + pkt_len)) { 605 rcvpartdupbyte += q->ipqe_len; 606 m_freem(q->ipqe_m); 607 TCP_REASS_COUNTER_INCR(&tcp_reass_fragdup); 608 goto free_ipqe; 609 } 610 /* 611 * RX'ed segment extends past the end of the 612 * fragment. Drop the overlapping bytes. Then 613 * merge the fragment and segment then treat as 614 * a longer received packet. 615 */ 616 if (SEQ_LT(q->ipqe_seq, pkt_seq) && 617 SEQ_GT(q->ipqe_seq + q->ipqe_len, pkt_seq)) { 618 int overlap = q->ipqe_seq + q->ipqe_len - pkt_seq; 619 #ifdef TCPREASS_DEBUG 620 printf("tcp_reass[%p]: trim starting %d bytes of %u:%u(%u)\n", 621 tp, overlap, 622 pkt_seq, pkt_seq + pkt_len, pkt_len); 623 #endif 624 m_adj(m, overlap); 625 rcvpartdupbyte += overlap; 626 m_cat(q->ipre_mlast, m); 627 TRAVERSE(q->ipre_mlast); 628 m = q->ipqe_m; 629 pkt_seq = q->ipqe_seq; 630 pkt_len += q->ipqe_len - overlap; 631 rcvoobyte -= overlap; 632 TCP_REASS_COUNTER_INCR(&tcp_reass_overlaptail); 633 goto free_ipqe; 634 } 635 /* 636 * RX'ed segment extends past the front of the 637 * fragment. Drop the overlapping bytes on the 638 * received packet. The packet will then be 639 * contatentated with this fragment a bit later. 640 */ 641 if (SEQ_GT(q->ipqe_seq, pkt_seq) && 642 SEQ_LT(q->ipqe_seq, pkt_seq + pkt_len)) { 643 int overlap = pkt_seq + pkt_len - q->ipqe_seq; 644 #ifdef TCPREASS_DEBUG 645 printf("tcp_reass[%p]: trim trailing %d bytes of %u:%u(%u)\n", 646 tp, overlap, 647 pkt_seq, pkt_seq + pkt_len, pkt_len); 648 #endif 649 m_adj(m, -overlap); 650 pkt_len -= overlap; 651 rcvpartdupbyte += overlap; 652 TCP_REASS_COUNTER_INCR(&tcp_reass_overlapfront); 653 rcvoobyte -= overlap; 654 } 655 /* 656 * If the received segment immediates precedes this 657 * fragment then tack the fragment onto this segment 658 * and reinsert the data. 659 */ 660 if (q->ipqe_seq == pkt_seq + pkt_len) { 661 #ifdef TCPREASS_DEBUG 662 printf("tcp_reass[%p]: append %u:%u(%u) to %u:%u(%u)\n", 663 tp, q->ipqe_seq, q->ipqe_seq + q->ipqe_len, q->ipqe_len, 664 pkt_seq, pkt_seq + pkt_len, pkt_len); 665 #endif 666 pkt_len += q->ipqe_len; 667 pkt_flags |= q->ipqe_flags; 668 m_cat(m, q->ipqe_m); 669 TAILQ_REMOVE(&tp->segq, q, ipqe_q); 670 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 671 tp->t_segqlen--; 672 KASSERT(tp->t_segqlen >= 0); 673 KASSERT(tp->t_segqlen != 0 || 674 (TAILQ_EMPTY(&tp->segq) && 675 TAILQ_EMPTY(&tp->timeq))); 676 if (tiqe == NULL) { 677 tiqe = q; 678 } else { 679 tcpipqent_free(q); 680 } 681 TCP_REASS_COUNTER_INCR(&tcp_reass_prepend); 682 break; 683 } 684 /* 685 * If the fragment is before the segment, remember it. 686 * When this loop is terminated, p will contain the 687 * pointer to fragment that is right before the received 688 * segment. 689 */ 690 if (SEQ_LEQ(q->ipqe_seq, pkt_seq)) 691 p = q; 692 693 continue; 694 695 /* 696 * This is a common operation. It also will allow 697 * to save doing a malloc/free in most instances. 698 */ 699 free_ipqe: 700 TAILQ_REMOVE(&tp->segq, q, ipqe_q); 701 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 702 tp->t_segqlen--; 703 KASSERT(tp->t_segqlen >= 0); 704 KASSERT(tp->t_segqlen != 0 || 705 (TAILQ_EMPTY(&tp->segq) && TAILQ_EMPTY(&tp->timeq))); 706 if (tiqe == NULL) { 707 tiqe = q; 708 } else { 709 tcpipqent_free(q); 710 } 711 } 712 713 #ifdef TCP_REASS_COUNTERS 714 if (count > 7) 715 TCP_REASS_COUNTER_INCR(&tcp_reass_iteration[0]); 716 else if (count > 0) 717 TCP_REASS_COUNTER_INCR(&tcp_reass_iteration[count]); 718 #endif 719 720 insert_it: 721 722 /* 723 * Allocate a new queue entry since the received segment did not 724 * collapse onto any other out-of-order block; thus we are allocating 725 * a new block. If it had collapsed, tiqe would not be NULL and 726 * we would be reusing it. 727 * XXX If we can't, just drop the packet. XXX 728 */ 729 if (tiqe == NULL) { 730 tiqe = tcpipqent_alloc(); 731 if (tiqe == NULL) { 732 TCP_STATINC(TCP_STAT_RCVMEMDROP); 733 m_freem(m); 734 return (0); 735 } 736 } 737 738 /* 739 * Update the counters. 740 */ 741 tcps = TCP_STAT_GETREF(); 742 tcps[TCP_STAT_RCVOOPACK]++; 743 tcps[TCP_STAT_RCVOOBYTE] += rcvoobyte; 744 if (rcvpartdupbyte) { 745 tcps[TCP_STAT_RCVPARTDUPPACK]++; 746 tcps[TCP_STAT_RCVPARTDUPBYTE] += rcvpartdupbyte; 747 } 748 TCP_STAT_PUTREF(); 749 750 /* 751 * Insert the new fragment queue entry into both queues. 752 */ 753 tiqe->ipqe_m = m; 754 tiqe->ipre_mlast = m; 755 tiqe->ipqe_seq = pkt_seq; 756 tiqe->ipqe_len = pkt_len; 757 tiqe->ipqe_flags = pkt_flags; 758 if (p == NULL) { 759 TAILQ_INSERT_HEAD(&tp->segq, tiqe, ipqe_q); 760 #ifdef TCPREASS_DEBUG 761 if (tiqe->ipqe_seq != tp->rcv_nxt) 762 printf("tcp_reass[%p]: insert %u:%u(%u) at front\n", 763 tp, pkt_seq, pkt_seq + pkt_len, pkt_len); 764 #endif 765 } else { 766 TAILQ_INSERT_AFTER(&tp->segq, p, tiqe, ipqe_q); 767 #ifdef TCPREASS_DEBUG 768 printf("tcp_reass[%p]: insert %u:%u(%u) after %u:%u(%u)\n", 769 tp, pkt_seq, pkt_seq + pkt_len, pkt_len, 770 p->ipqe_seq, p->ipqe_seq + p->ipqe_len, p->ipqe_len); 771 #endif 772 } 773 tp->t_segqlen++; 774 775 skip_replacement: 776 777 TAILQ_INSERT_HEAD(&tp->timeq, tiqe, ipqe_timeq); 778 779 present: 780 /* 781 * Present data to user, advancing rcv_nxt through 782 * completed sequence space. 783 */ 784 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 785 return (0); 786 q = TAILQ_FIRST(&tp->segq); 787 if (q == NULL || q->ipqe_seq != tp->rcv_nxt) 788 return (0); 789 if (tp->t_state == TCPS_SYN_RECEIVED && q->ipqe_len) 790 return (0); 791 792 tp->rcv_nxt += q->ipqe_len; 793 pkt_flags = q->ipqe_flags & TH_FIN; 794 nd6_hint(tp); 795 796 TAILQ_REMOVE(&tp->segq, q, ipqe_q); 797 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 798 tp->t_segqlen--; 799 KASSERT(tp->t_segqlen >= 0); 800 KASSERT(tp->t_segqlen != 0 || 801 (TAILQ_EMPTY(&tp->segq) && TAILQ_EMPTY(&tp->timeq))); 802 if (so->so_state & SS_CANTRCVMORE) 803 m_freem(q->ipqe_m); 804 else 805 sbappendstream(&so->so_rcv, q->ipqe_m); 806 tcpipqent_free(q); 807 sorwakeup(so); 808 return (pkt_flags); 809 } 810 811 #ifdef INET6 812 int 813 tcp6_input(struct mbuf **mp, int *offp, int proto) 814 { 815 struct mbuf *m = *mp; 816 817 /* 818 * draft-itojun-ipv6-tcp-to-anycast 819 * better place to put this in? 820 */ 821 if (m->m_flags & M_ANYCAST6) { 822 struct ip6_hdr *ip6; 823 if (m->m_len < sizeof(struct ip6_hdr)) { 824 if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) { 825 TCP_STATINC(TCP_STAT_RCVSHORT); 826 return IPPROTO_DONE; 827 } 828 } 829 ip6 = mtod(m, struct ip6_hdr *); 830 icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR, 831 (char *)&ip6->ip6_dst - (char *)ip6); 832 return IPPROTO_DONE; 833 } 834 835 tcp_input(m, *offp, proto); 836 return IPPROTO_DONE; 837 } 838 #endif 839 840 #ifdef INET 841 static void 842 tcp4_log_refused(const struct ip *ip, const struct tcphdr *th) 843 { 844 char src[4*sizeof "123"]; 845 char dst[4*sizeof "123"]; 846 847 if (ip) { 848 strlcpy(src, inet_ntoa(ip->ip_src), sizeof(src)); 849 strlcpy(dst, inet_ntoa(ip->ip_dst), sizeof(dst)); 850 } 851 else { 852 strlcpy(src, "(unknown)", sizeof(src)); 853 strlcpy(dst, "(unknown)", sizeof(dst)); 854 } 855 log(LOG_INFO, 856 "Connection attempt to TCP %s:%d from %s:%d\n", 857 dst, ntohs(th->th_dport), 858 src, ntohs(th->th_sport)); 859 } 860 #endif 861 862 #ifdef INET6 863 static void 864 tcp6_log_refused(const struct ip6_hdr *ip6, const struct tcphdr *th) 865 { 866 char src[INET6_ADDRSTRLEN]; 867 char dst[INET6_ADDRSTRLEN]; 868 869 if (ip6) { 870 strlcpy(src, ip6_sprintf(&ip6->ip6_src), sizeof(src)); 871 strlcpy(dst, ip6_sprintf(&ip6->ip6_dst), sizeof(dst)); 872 } 873 else { 874 strlcpy(src, "(unknown v6)", sizeof(src)); 875 strlcpy(dst, "(unknown v6)", sizeof(dst)); 876 } 877 log(LOG_INFO, 878 "Connection attempt to TCP [%s]:%d from [%s]:%d\n", 879 dst, ntohs(th->th_dport), 880 src, ntohs(th->th_sport)); 881 } 882 #endif 883 884 /* 885 * Checksum extended TCP header and data. 886 */ 887 int 888 tcp_input_checksum(int af, struct mbuf *m, const struct tcphdr *th, 889 int toff, int off, int tlen) 890 { 891 892 /* 893 * XXX it's better to record and check if this mbuf is 894 * already checked. 895 */ 896 897 switch (af) { 898 #ifdef INET 899 case AF_INET: 900 switch (m->m_pkthdr.csum_flags & 901 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_TCPv4) | 902 M_CSUM_TCP_UDP_BAD | M_CSUM_DATA)) { 903 case M_CSUM_TCPv4|M_CSUM_TCP_UDP_BAD: 904 TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_bad); 905 goto badcsum; 906 907 case M_CSUM_TCPv4|M_CSUM_DATA: { 908 u_int32_t hw_csum = m->m_pkthdr.csum_data; 909 910 TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_data); 911 if (m->m_pkthdr.csum_flags & M_CSUM_NO_PSEUDOHDR) { 912 const struct ip *ip = 913 mtod(m, const struct ip *); 914 915 hw_csum = in_cksum_phdr(ip->ip_src.s_addr, 916 ip->ip_dst.s_addr, 917 htons(hw_csum + tlen + off + IPPROTO_TCP)); 918 } 919 if ((hw_csum ^ 0xffff) != 0) 920 goto badcsum; 921 break; 922 } 923 924 case M_CSUM_TCPv4: 925 /* Checksum was okay. */ 926 TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_ok); 927 break; 928 929 default: 930 /* 931 * Must compute it ourselves. Maybe skip checksum 932 * on loopback interfaces. 933 */ 934 if (__predict_true(!(m->m_pkthdr.rcvif->if_flags & 935 IFF_LOOPBACK) || 936 tcp_do_loopback_cksum)) { 937 TCP_CSUM_COUNTER_INCR(&tcp_swcsum); 938 if (in4_cksum(m, IPPROTO_TCP, toff, 939 tlen + off) != 0) 940 goto badcsum; 941 } 942 break; 943 } 944 break; 945 #endif /* INET4 */ 946 947 #ifdef INET6 948 case AF_INET6: 949 switch (m->m_pkthdr.csum_flags & 950 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_TCPv6) | 951 M_CSUM_TCP_UDP_BAD | M_CSUM_DATA)) { 952 case M_CSUM_TCPv6|M_CSUM_TCP_UDP_BAD: 953 TCP_CSUM_COUNTER_INCR(&tcp6_hwcsum_bad); 954 goto badcsum; 955 956 #if 0 /* notyet */ 957 case M_CSUM_TCPv6|M_CSUM_DATA: 958 #endif 959 960 case M_CSUM_TCPv6: 961 /* Checksum was okay. */ 962 TCP_CSUM_COUNTER_INCR(&tcp6_hwcsum_ok); 963 break; 964 965 default: 966 /* 967 * Must compute it ourselves. Maybe skip checksum 968 * on loopback interfaces. 969 */ 970 if (__predict_true((m->m_flags & M_LOOP) == 0 || 971 tcp_do_loopback_cksum)) { 972 TCP_CSUM_COUNTER_INCR(&tcp6_swcsum); 973 if (in6_cksum(m, IPPROTO_TCP, toff, 974 tlen + off) != 0) 975 goto badcsum; 976 } 977 } 978 break; 979 #endif /* INET6 */ 980 } 981 982 return 0; 983 984 badcsum: 985 TCP_STATINC(TCP_STAT_RCVBADSUM); 986 return -1; 987 } 988 989 /* 990 * TCP input routine, follows pages 65-76 of RFC 793 very closely. 991 */ 992 void 993 tcp_input(struct mbuf *m, ...) 994 { 995 struct tcphdr *th; 996 struct ip *ip; 997 struct inpcb *inp; 998 #ifdef INET6 999 struct ip6_hdr *ip6; 1000 struct in6pcb *in6p; 1001 #endif 1002 u_int8_t *optp = NULL; 1003 int optlen = 0; 1004 int len, tlen, toff, hdroptlen = 0; 1005 struct tcpcb *tp = 0; 1006 int tiflags; 1007 struct socket *so = NULL; 1008 int todrop, dupseg, acked, ourfinisacked, needoutput = 0; 1009 #ifdef TCP_DEBUG 1010 short ostate = 0; 1011 #endif 1012 u_long tiwin; 1013 struct tcp_opt_info opti; 1014 int off, iphlen; 1015 va_list ap; 1016 int af; /* af on the wire */ 1017 struct mbuf *tcp_saveti = NULL; 1018 uint32_t ts_rtt; 1019 uint8_t iptos; 1020 uint64_t *tcps; 1021 1022 MCLAIM(m, &tcp_rx_mowner); 1023 va_start(ap, m); 1024 toff = va_arg(ap, int); 1025 (void)va_arg(ap, int); /* ignore value, advance ap */ 1026 va_end(ap); 1027 1028 TCP_STATINC(TCP_STAT_RCVTOTAL); 1029 1030 memset(&opti, 0, sizeof(opti)); 1031 opti.ts_present = 0; 1032 opti.maxseg = 0; 1033 1034 /* 1035 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN. 1036 * 1037 * TCP is, by definition, unicast, so we reject all 1038 * multicast outright. 1039 * 1040 * Note, there are additional src/dst address checks in 1041 * the AF-specific code below. 1042 */ 1043 if (m->m_flags & (M_BCAST|M_MCAST)) { 1044 /* XXX stat */ 1045 goto drop; 1046 } 1047 #ifdef INET6 1048 if (m->m_flags & M_ANYCAST6) { 1049 /* XXX stat */ 1050 goto drop; 1051 } 1052 #endif 1053 1054 /* 1055 * Get IP and TCP header. 1056 * Note: IP leaves IP header in first mbuf. 1057 */ 1058 ip = mtod(m, struct ip *); 1059 #ifdef INET6 1060 ip6 = NULL; 1061 #endif 1062 switch (ip->ip_v) { 1063 #ifdef INET 1064 case 4: 1065 af = AF_INET; 1066 iphlen = sizeof(struct ip); 1067 ip = mtod(m, struct ip *); 1068 IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, 1069 sizeof(struct tcphdr)); 1070 if (th == NULL) { 1071 TCP_STATINC(TCP_STAT_RCVSHORT); 1072 return; 1073 } 1074 /* We do the checksum after PCB lookup... */ 1075 len = ntohs(ip->ip_len); 1076 tlen = len - toff; 1077 iptos = ip->ip_tos; 1078 break; 1079 #endif 1080 #ifdef INET6 1081 case 6: 1082 ip = NULL; 1083 iphlen = sizeof(struct ip6_hdr); 1084 af = AF_INET6; 1085 ip6 = mtod(m, struct ip6_hdr *); 1086 IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, 1087 sizeof(struct tcphdr)); 1088 if (th == NULL) { 1089 TCP_STATINC(TCP_STAT_RCVSHORT); 1090 return; 1091 } 1092 1093 /* Be proactive about malicious use of IPv4 mapped address */ 1094 if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) || 1095 IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) { 1096 /* XXX stat */ 1097 goto drop; 1098 } 1099 1100 /* 1101 * Be proactive about unspecified IPv6 address in source. 1102 * As we use all-zero to indicate unbounded/unconnected pcb, 1103 * unspecified IPv6 address can be used to confuse us. 1104 * 1105 * Note that packets with unspecified IPv6 destination is 1106 * already dropped in ip6_input. 1107 */ 1108 if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 1109 /* XXX stat */ 1110 goto drop; 1111 } 1112 1113 /* 1114 * Make sure destination address is not multicast. 1115 * Source address checked in ip6_input(). 1116 */ 1117 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) { 1118 /* XXX stat */ 1119 goto drop; 1120 } 1121 1122 /* We do the checksum after PCB lookup... */ 1123 len = m->m_pkthdr.len; 1124 tlen = len - toff; 1125 iptos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 1126 break; 1127 #endif 1128 default: 1129 m_freem(m); 1130 return; 1131 } 1132 1133 KASSERT(TCP_HDR_ALIGNED_P(th)); 1134 1135 /* 1136 * Check that TCP offset makes sense, 1137 * pull out TCP options and adjust length. XXX 1138 */ 1139 off = th->th_off << 2; 1140 if (off < sizeof (struct tcphdr) || off > tlen) { 1141 TCP_STATINC(TCP_STAT_RCVBADOFF); 1142 goto drop; 1143 } 1144 tlen -= off; 1145 1146 /* 1147 * tcp_input() has been modified to use tlen to mean the TCP data 1148 * length throughout the function. Other functions can use 1149 * m->m_pkthdr.len as the basis for calculating the TCP data length. 1150 * rja 1151 */ 1152 1153 if (off > sizeof (struct tcphdr)) { 1154 IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, off); 1155 if (th == NULL) { 1156 TCP_STATINC(TCP_STAT_RCVSHORT); 1157 return; 1158 } 1159 /* 1160 * NOTE: ip/ip6 will not be affected by m_pulldown() 1161 * (as they're before toff) and we don't need to update those. 1162 */ 1163 KASSERT(TCP_HDR_ALIGNED_P(th)); 1164 optlen = off - sizeof (struct tcphdr); 1165 optp = ((u_int8_t *)th) + sizeof(struct tcphdr); 1166 /* 1167 * Do quick retrieval of timestamp options ("options 1168 * prediction?"). If timestamp is the only option and it's 1169 * formatted as recommended in RFC 1323 appendix A, we 1170 * quickly get the values now and not bother calling 1171 * tcp_dooptions(), etc. 1172 */ 1173 if ((optlen == TCPOLEN_TSTAMP_APPA || 1174 (optlen > TCPOLEN_TSTAMP_APPA && 1175 optp[TCPOLEN_TSTAMP_APPA] == TCPOPT_EOL)) && 1176 *(u_int32_t *)optp == htonl(TCPOPT_TSTAMP_HDR) && 1177 (th->th_flags & TH_SYN) == 0) { 1178 opti.ts_present = 1; 1179 opti.ts_val = ntohl(*(u_int32_t *)(optp + 4)); 1180 opti.ts_ecr = ntohl(*(u_int32_t *)(optp + 8)); 1181 optp = NULL; /* we've parsed the options */ 1182 } 1183 } 1184 tiflags = th->th_flags; 1185 1186 /* 1187 * Locate pcb for segment. 1188 */ 1189 findpcb: 1190 inp = NULL; 1191 #ifdef INET6 1192 in6p = NULL; 1193 #endif 1194 switch (af) { 1195 #ifdef INET 1196 case AF_INET: 1197 inp = in_pcblookup_connect(&tcbtable, ip->ip_src, th->th_sport, 1198 ip->ip_dst, th->th_dport); 1199 if (inp == 0) { 1200 TCP_STATINC(TCP_STAT_PCBHASHMISS); 1201 inp = in_pcblookup_bind(&tcbtable, ip->ip_dst, th->th_dport); 1202 } 1203 #ifdef INET6 1204 if (inp == 0) { 1205 struct in6_addr s, d; 1206 1207 /* mapped addr case */ 1208 memset(&s, 0, sizeof(s)); 1209 s.s6_addr16[5] = htons(0xffff); 1210 bcopy(&ip->ip_src, &s.s6_addr32[3], sizeof(ip->ip_src)); 1211 memset(&d, 0, sizeof(d)); 1212 d.s6_addr16[5] = htons(0xffff); 1213 bcopy(&ip->ip_dst, &d.s6_addr32[3], sizeof(ip->ip_dst)); 1214 in6p = in6_pcblookup_connect(&tcbtable, &s, 1215 th->th_sport, &d, th->th_dport, 0); 1216 if (in6p == 0) { 1217 TCP_STATINC(TCP_STAT_PCBHASHMISS); 1218 in6p = in6_pcblookup_bind(&tcbtable, &d, 1219 th->th_dport, 0); 1220 } 1221 } 1222 #endif 1223 #ifndef INET6 1224 if (inp == 0) 1225 #else 1226 if (inp == 0 && in6p == 0) 1227 #endif 1228 { 1229 TCP_STATINC(TCP_STAT_NOPORT); 1230 if (tcp_log_refused && 1231 (tiflags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN) { 1232 tcp4_log_refused(ip, th); 1233 } 1234 tcp_fields_to_host(th); 1235 goto dropwithreset_ratelim; 1236 } 1237 #if defined(IPSEC) || defined(FAST_IPSEC) 1238 if (inp && (inp->inp_socket->so_options & SO_ACCEPTCONN) == 0 && 1239 ipsec4_in_reject(m, inp)) { 1240 IPSEC_STATINC(IPSEC_STAT_IN_POLVIO); 1241 goto drop; 1242 } 1243 #ifdef INET6 1244 else if (in6p && 1245 (in6p->in6p_socket->so_options & SO_ACCEPTCONN) == 0 && 1246 ipsec6_in_reject_so(m, in6p->in6p_socket)) { 1247 IPSEC_STATINC(IPSEC_STAT_IN_POLVIO); 1248 goto drop; 1249 } 1250 #endif 1251 #endif /*IPSEC*/ 1252 break; 1253 #endif /*INET*/ 1254 #ifdef INET6 1255 case AF_INET6: 1256 { 1257 int faith; 1258 1259 #if defined(NFAITH) && NFAITH > 0 1260 faith = faithprefix(&ip6->ip6_dst); 1261 #else 1262 faith = 0; 1263 #endif 1264 in6p = in6_pcblookup_connect(&tcbtable, &ip6->ip6_src, 1265 th->th_sport, &ip6->ip6_dst, th->th_dport, faith); 1266 if (in6p == NULL) { 1267 TCP_STATINC(TCP_STAT_PCBHASHMISS); 1268 in6p = in6_pcblookup_bind(&tcbtable, &ip6->ip6_dst, 1269 th->th_dport, faith); 1270 } 1271 if (in6p == NULL) { 1272 TCP_STATINC(TCP_STAT_NOPORT); 1273 if (tcp_log_refused && 1274 (tiflags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN) { 1275 tcp6_log_refused(ip6, th); 1276 } 1277 tcp_fields_to_host(th); 1278 goto dropwithreset_ratelim; 1279 } 1280 #if defined(IPSEC) || defined(FAST_IPSEC) 1281 if ((in6p->in6p_socket->so_options & SO_ACCEPTCONN) == 0 && 1282 ipsec6_in_reject(m, in6p)) { 1283 IPSEC6_STATINC(IPSEC_STAT_IN_POLVIO); 1284 goto drop; 1285 } 1286 #endif /*IPSEC*/ 1287 break; 1288 } 1289 #endif 1290 } 1291 1292 /* 1293 * If the state is CLOSED (i.e., TCB does not exist) then 1294 * all data in the incoming segment is discarded. 1295 * If the TCB exists but is in CLOSED state, it is embryonic, 1296 * but should either do a listen or a connect soon. 1297 */ 1298 tp = NULL; 1299 so = NULL; 1300 if (inp) { 1301 tp = intotcpcb(inp); 1302 so = inp->inp_socket; 1303 } 1304 #ifdef INET6 1305 else if (in6p) { 1306 tp = in6totcpcb(in6p); 1307 so = in6p->in6p_socket; 1308 } 1309 #endif 1310 if (tp == 0) { 1311 tcp_fields_to_host(th); 1312 goto dropwithreset_ratelim; 1313 } 1314 if (tp->t_state == TCPS_CLOSED) 1315 goto drop; 1316 1317 KASSERT(so->so_lock == softnet_lock); 1318 KASSERT(solocked(so)); 1319 1320 /* 1321 * Checksum extended TCP header and data. 1322 */ 1323 if (tcp_input_checksum(af, m, th, toff, off, tlen)) 1324 goto badcsum; 1325 1326 tcp_fields_to_host(th); 1327 1328 /* Unscale the window into a 32-bit value. */ 1329 if ((tiflags & TH_SYN) == 0) 1330 tiwin = th->th_win << tp->snd_scale; 1331 else 1332 tiwin = th->th_win; 1333 1334 #ifdef INET6 1335 /* save packet options if user wanted */ 1336 if (in6p && (in6p->in6p_flags & IN6P_CONTROLOPTS)) { 1337 if (in6p->in6p_options) { 1338 m_freem(in6p->in6p_options); 1339 in6p->in6p_options = 0; 1340 } 1341 KASSERT(ip6 != NULL); 1342 ip6_savecontrol(in6p, &in6p->in6p_options, ip6, m); 1343 } 1344 #endif 1345 1346 if (so->so_options & (SO_DEBUG|SO_ACCEPTCONN)) { 1347 union syn_cache_sa src; 1348 union syn_cache_sa dst; 1349 1350 memset(&src, 0, sizeof(src)); 1351 memset(&dst, 0, sizeof(dst)); 1352 switch (af) { 1353 #ifdef INET 1354 case AF_INET: 1355 src.sin.sin_len = sizeof(struct sockaddr_in); 1356 src.sin.sin_family = AF_INET; 1357 src.sin.sin_addr = ip->ip_src; 1358 src.sin.sin_port = th->th_sport; 1359 1360 dst.sin.sin_len = sizeof(struct sockaddr_in); 1361 dst.sin.sin_family = AF_INET; 1362 dst.sin.sin_addr = ip->ip_dst; 1363 dst.sin.sin_port = th->th_dport; 1364 break; 1365 #endif 1366 #ifdef INET6 1367 case AF_INET6: 1368 src.sin6.sin6_len = sizeof(struct sockaddr_in6); 1369 src.sin6.sin6_family = AF_INET6; 1370 src.sin6.sin6_addr = ip6->ip6_src; 1371 src.sin6.sin6_port = th->th_sport; 1372 1373 dst.sin6.sin6_len = sizeof(struct sockaddr_in6); 1374 dst.sin6.sin6_family = AF_INET6; 1375 dst.sin6.sin6_addr = ip6->ip6_dst; 1376 dst.sin6.sin6_port = th->th_dport; 1377 break; 1378 #endif /* INET6 */ 1379 default: 1380 goto badsyn; /*sanity*/ 1381 } 1382 1383 if (so->so_options & SO_DEBUG) { 1384 #ifdef TCP_DEBUG 1385 ostate = tp->t_state; 1386 #endif 1387 1388 tcp_saveti = NULL; 1389 if (iphlen + sizeof(struct tcphdr) > MHLEN) 1390 goto nosave; 1391 1392 if (m->m_len > iphlen && (m->m_flags & M_EXT) == 0) { 1393 tcp_saveti = m_copym(m, 0, iphlen, M_DONTWAIT); 1394 if (!tcp_saveti) 1395 goto nosave; 1396 } else { 1397 MGETHDR(tcp_saveti, M_DONTWAIT, MT_HEADER); 1398 if (!tcp_saveti) 1399 goto nosave; 1400 MCLAIM(m, &tcp_mowner); 1401 tcp_saveti->m_len = iphlen; 1402 m_copydata(m, 0, iphlen, 1403 mtod(tcp_saveti, void *)); 1404 } 1405 1406 if (M_TRAILINGSPACE(tcp_saveti) < sizeof(struct tcphdr)) { 1407 m_freem(tcp_saveti); 1408 tcp_saveti = NULL; 1409 } else { 1410 tcp_saveti->m_len += sizeof(struct tcphdr); 1411 memcpy(mtod(tcp_saveti, char *) + iphlen, th, 1412 sizeof(struct tcphdr)); 1413 } 1414 nosave:; 1415 } 1416 if (so->so_options & SO_ACCEPTCONN) { 1417 if ((tiflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) { 1418 if (tiflags & TH_RST) { 1419 syn_cache_reset(&src.sa, &dst.sa, th); 1420 } else if ((tiflags & (TH_ACK|TH_SYN)) == 1421 (TH_ACK|TH_SYN)) { 1422 /* 1423 * Received a SYN,ACK. This should 1424 * never happen while we are in 1425 * LISTEN. Send an RST. 1426 */ 1427 goto badsyn; 1428 } else if (tiflags & TH_ACK) { 1429 so = syn_cache_get(&src.sa, &dst.sa, 1430 th, toff, tlen, so, m); 1431 if (so == NULL) { 1432 /* 1433 * We don't have a SYN for 1434 * this ACK; send an RST. 1435 */ 1436 goto badsyn; 1437 } else if (so == 1438 (struct socket *)(-1)) { 1439 /* 1440 * We were unable to create 1441 * the connection. If the 1442 * 3-way handshake was 1443 * completed, and RST has 1444 * been sent to the peer. 1445 * Since the mbuf might be 1446 * in use for the reply, 1447 * do not free it. 1448 */ 1449 m = NULL; 1450 } else { 1451 /* 1452 * We have created a 1453 * full-blown connection. 1454 */ 1455 tp = NULL; 1456 inp = NULL; 1457 #ifdef INET6 1458 in6p = NULL; 1459 #endif 1460 switch (so->so_proto->pr_domain->dom_family) { 1461 #ifdef INET 1462 case AF_INET: 1463 inp = sotoinpcb(so); 1464 tp = intotcpcb(inp); 1465 break; 1466 #endif 1467 #ifdef INET6 1468 case AF_INET6: 1469 in6p = sotoin6pcb(so); 1470 tp = in6totcpcb(in6p); 1471 break; 1472 #endif 1473 } 1474 if (tp == NULL) 1475 goto badsyn; /*XXX*/ 1476 tiwin <<= tp->snd_scale; 1477 goto after_listen; 1478 } 1479 } else { 1480 /* 1481 * None of RST, SYN or ACK was set. 1482 * This is an invalid packet for a 1483 * TCB in LISTEN state. Send a RST. 1484 */ 1485 goto badsyn; 1486 } 1487 } else { 1488 /* 1489 * Received a SYN. 1490 * 1491 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN 1492 */ 1493 if (m->m_flags & (M_BCAST|M_MCAST)) 1494 goto drop; 1495 1496 switch (af) { 1497 #ifdef INET6 1498 case AF_INET6: 1499 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) 1500 goto drop; 1501 break; 1502 #endif /* INET6 */ 1503 case AF_INET: 1504 if (IN_MULTICAST(ip->ip_dst.s_addr) || 1505 in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) 1506 goto drop; 1507 break; 1508 } 1509 1510 #ifdef INET6 1511 /* 1512 * If deprecated address is forbidden, we do 1513 * not accept SYN to deprecated interface 1514 * address to prevent any new inbound 1515 * connection from getting established. 1516 * When we do not accept SYN, we send a TCP 1517 * RST, with deprecated source address (instead 1518 * of dropping it). We compromise it as it is 1519 * much better for peer to send a RST, and 1520 * RST will be the final packet for the 1521 * exchange. 1522 * 1523 * If we do not forbid deprecated addresses, we 1524 * accept the SYN packet. RFC2462 does not 1525 * suggest dropping SYN in this case. 1526 * If we decipher RFC2462 5.5.4, it says like 1527 * this: 1528 * 1. use of deprecated addr with existing 1529 * communication is okay - "SHOULD continue 1530 * to be used" 1531 * 2. use of it with new communication: 1532 * (2a) "SHOULD NOT be used if alternate 1533 * address with sufficient scope is 1534 * available" 1535 * (2b) nothing mentioned otherwise. 1536 * Here we fall into (2b) case as we have no 1537 * choice in our source address selection - we 1538 * must obey the peer. 1539 * 1540 * The wording in RFC2462 is confusing, and 1541 * there are multiple description text for 1542 * deprecated address handling - worse, they 1543 * are not exactly the same. I believe 5.5.4 1544 * is the best one, so we follow 5.5.4. 1545 */ 1546 if (af == AF_INET6 && !ip6_use_deprecated) { 1547 struct in6_ifaddr *ia6; 1548 if ((ia6 = in6ifa_ifpwithaddr(m->m_pkthdr.rcvif, 1549 &ip6->ip6_dst)) && 1550 (ia6->ia6_flags & IN6_IFF_DEPRECATED)) { 1551 tp = NULL; 1552 goto dropwithreset; 1553 } 1554 } 1555 #endif 1556 1557 #if defined(IPSEC) || defined(FAST_IPSEC) 1558 switch (af) { 1559 #ifdef INET 1560 case AF_INET: 1561 if (ipsec4_in_reject_so(m, so)) { 1562 IPSEC_STATINC(IPSEC_STAT_IN_POLVIO); 1563 tp = NULL; 1564 goto dropwithreset; 1565 } 1566 break; 1567 #endif 1568 #ifdef INET6 1569 case AF_INET6: 1570 if (ipsec6_in_reject_so(m, so)) { 1571 IPSEC6_STATINC(IPSEC_STAT_IN_POLVIO); 1572 tp = NULL; 1573 goto dropwithreset; 1574 } 1575 break; 1576 #endif /*INET6*/ 1577 } 1578 #endif /*IPSEC*/ 1579 1580 /* 1581 * LISTEN socket received a SYN 1582 * from itself? This can't possibly 1583 * be valid; drop the packet. 1584 */ 1585 if (th->th_sport == th->th_dport) { 1586 int i; 1587 1588 switch (af) { 1589 #ifdef INET 1590 case AF_INET: 1591 i = in_hosteq(ip->ip_src, ip->ip_dst); 1592 break; 1593 #endif 1594 #ifdef INET6 1595 case AF_INET6: 1596 i = IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &ip6->ip6_dst); 1597 break; 1598 #endif 1599 default: 1600 i = 1; 1601 } 1602 if (i) { 1603 TCP_STATINC(TCP_STAT_BADSYN); 1604 goto drop; 1605 } 1606 } 1607 1608 /* 1609 * SYN looks ok; create compressed TCP 1610 * state for it. 1611 */ 1612 if (so->so_qlen <= so->so_qlimit && 1613 syn_cache_add(&src.sa, &dst.sa, th, tlen, 1614 so, m, optp, optlen, &opti)) 1615 m = NULL; 1616 } 1617 goto drop; 1618 } 1619 } 1620 1621 after_listen: 1622 #ifdef DIAGNOSTIC 1623 /* 1624 * Should not happen now that all embryonic connections 1625 * are handled with compressed state. 1626 */ 1627 if (tp->t_state == TCPS_LISTEN) 1628 panic("tcp_input: TCPS_LISTEN"); 1629 #endif 1630 1631 /* 1632 * Segment received on connection. 1633 * Reset idle time and keep-alive timer. 1634 */ 1635 tp->t_rcvtime = tcp_now; 1636 if (TCPS_HAVEESTABLISHED(tp->t_state)) 1637 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle); 1638 1639 /* 1640 * Process options. 1641 */ 1642 #ifdef TCP_SIGNATURE 1643 if (optp || (tp->t_flags & TF_SIGNATURE)) 1644 #else 1645 if (optp) 1646 #endif 1647 if (tcp_dooptions(tp, optp, optlen, th, m, toff, &opti) < 0) 1648 goto drop; 1649 1650 if (TCP_SACK_ENABLED(tp)) { 1651 tcp_del_sackholes(tp, th); 1652 } 1653 1654 if (TCP_ECN_ALLOWED(tp)) { 1655 switch (iptos & IPTOS_ECN_MASK) { 1656 case IPTOS_ECN_CE: 1657 tp->t_flags |= TF_ECN_SND_ECE; 1658 TCP_STATINC(TCP_STAT_ECN_CE); 1659 break; 1660 case IPTOS_ECN_ECT0: 1661 TCP_STATINC(TCP_STAT_ECN_ECT); 1662 break; 1663 case IPTOS_ECN_ECT1: 1664 /* XXX: ignore for now -- rpaulo */ 1665 break; 1666 } 1667 1668 if (tiflags & TH_CWR) 1669 tp->t_flags &= ~TF_ECN_SND_ECE; 1670 1671 /* 1672 * Congestion experienced. 1673 * Ignore if we are already trying to recover. 1674 */ 1675 if ((tiflags & TH_ECE) && SEQ_GEQ(tp->snd_una, tp->snd_recover)) 1676 tp->t_congctl->cong_exp(tp); 1677 } 1678 1679 if (opti.ts_present && opti.ts_ecr) { 1680 /* 1681 * Calculate the RTT from the returned time stamp and the 1682 * connection's time base. If the time stamp is later than 1683 * the current time, or is extremely old, fall back to non-1323 1684 * RTT calculation. Since ts_ecr is unsigned, we can test both 1685 * at the same time. 1686 */ 1687 ts_rtt = TCP_TIMESTAMP(tp) - opti.ts_ecr + 1; 1688 if (ts_rtt > TCP_PAWS_IDLE) 1689 ts_rtt = 0; 1690 } else { 1691 ts_rtt = 0; 1692 } 1693 1694 /* 1695 * Header prediction: check for the two common cases 1696 * of a uni-directional data xfer. If the packet has 1697 * no control flags, is in-sequence, the window didn't 1698 * change and we're not retransmitting, it's a 1699 * candidate. If the length is zero and the ack moved 1700 * forward, we're the sender side of the xfer. Just 1701 * free the data acked & wake any higher level process 1702 * that was blocked waiting for space. If the length 1703 * is non-zero and the ack didn't move, we're the 1704 * receiver side. If we're getting packets in-order 1705 * (the reassembly queue is empty), add the data to 1706 * the socket buffer and note that we need a delayed ack. 1707 */ 1708 if (tp->t_state == TCPS_ESTABLISHED && 1709 (tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ECE|TH_CWR|TH_ACK)) 1710 == TH_ACK && 1711 (!opti.ts_present || TSTMP_GEQ(opti.ts_val, tp->ts_recent)) && 1712 th->th_seq == tp->rcv_nxt && 1713 tiwin && tiwin == tp->snd_wnd && 1714 tp->snd_nxt == tp->snd_max) { 1715 1716 /* 1717 * If last ACK falls within this segment's sequence numbers, 1718 * record the timestamp. 1719 * NOTE that the test is modified according to the latest 1720 * proposal of the tcplw@cray.com list (Braden 1993/04/26). 1721 * 1722 * note that we already know 1723 * TSTMP_GEQ(opti.ts_val, tp->ts_recent) 1724 */ 1725 if (opti.ts_present && 1726 SEQ_LEQ(th->th_seq, tp->last_ack_sent)) { 1727 tp->ts_recent_age = tcp_now; 1728 tp->ts_recent = opti.ts_val; 1729 } 1730 1731 if (tlen == 0) { 1732 /* Ack prediction. */ 1733 if (SEQ_GT(th->th_ack, tp->snd_una) && 1734 SEQ_LEQ(th->th_ack, tp->snd_max) && 1735 tp->snd_cwnd >= tp->snd_wnd && 1736 tp->t_partialacks < 0) { 1737 /* 1738 * this is a pure ack for outstanding data. 1739 */ 1740 if (ts_rtt) 1741 tcp_xmit_timer(tp, ts_rtt); 1742 else if (tp->t_rtttime && 1743 SEQ_GT(th->th_ack, tp->t_rtseq)) 1744 tcp_xmit_timer(tp, 1745 tcp_now - tp->t_rtttime); 1746 acked = th->th_ack - tp->snd_una; 1747 tcps = TCP_STAT_GETREF(); 1748 tcps[TCP_STAT_PREDACK]++; 1749 tcps[TCP_STAT_RCVACKPACK]++; 1750 tcps[TCP_STAT_RCVACKBYTE] += acked; 1751 TCP_STAT_PUTREF(); 1752 nd6_hint(tp); 1753 1754 if (acked > (tp->t_lastoff - tp->t_inoff)) 1755 tp->t_lastm = NULL; 1756 sbdrop(&so->so_snd, acked); 1757 tp->t_lastoff -= acked; 1758 1759 icmp_check(tp, th, acked); 1760 1761 tp->snd_una = th->th_ack; 1762 tp->snd_fack = tp->snd_una; 1763 if (SEQ_LT(tp->snd_high, tp->snd_una)) 1764 tp->snd_high = tp->snd_una; 1765 m_freem(m); 1766 1767 /* 1768 * If all outstanding data are acked, stop 1769 * retransmit timer, otherwise restart timer 1770 * using current (possibly backed-off) value. 1771 * If process is waiting for space, 1772 * wakeup/selnotify/signal. If data 1773 * are ready to send, let tcp_output 1774 * decide between more output or persist. 1775 */ 1776 if (tp->snd_una == tp->snd_max) 1777 TCP_TIMER_DISARM(tp, TCPT_REXMT); 1778 else if (TCP_TIMER_ISARMED(tp, 1779 TCPT_PERSIST) == 0) 1780 TCP_TIMER_ARM(tp, TCPT_REXMT, 1781 tp->t_rxtcur); 1782 1783 sowwakeup(so); 1784 if (so->so_snd.sb_cc) 1785 (void) tcp_output(tp); 1786 if (tcp_saveti) 1787 m_freem(tcp_saveti); 1788 return; 1789 } 1790 } else if (th->th_ack == tp->snd_una && 1791 TAILQ_FIRST(&tp->segq) == NULL && 1792 tlen <= sbspace(&so->so_rcv)) { 1793 int newsize = 0; /* automatic sockbuf scaling */ 1794 1795 /* 1796 * this is a pure, in-sequence data packet 1797 * with nothing on the reassembly queue and 1798 * we have enough buffer space to take it. 1799 */ 1800 tp->rcv_nxt += tlen; 1801 tcps = TCP_STAT_GETREF(); 1802 tcps[TCP_STAT_PREDDAT]++; 1803 tcps[TCP_STAT_RCVPACK]++; 1804 tcps[TCP_STAT_RCVBYTE] += tlen; 1805 TCP_STAT_PUTREF(); 1806 nd6_hint(tp); 1807 1808 /* 1809 * Automatic sizing enables the performance of large buffers 1810 * and most of the efficiency of small ones by only allocating 1811 * space when it is needed. 1812 * 1813 * On the receive side the socket buffer memory is only rarely 1814 * used to any significant extent. This allows us to be much 1815 * more aggressive in scaling the receive socket buffer. For 1816 * the case that the buffer space is actually used to a large 1817 * extent and we run out of kernel memory we can simply drop 1818 * the new segments; TCP on the sender will just retransmit it 1819 * later. Setting the buffer size too big may only consume too 1820 * much kernel memory if the application doesn't read() from 1821 * the socket or packet loss or reordering makes use of the 1822 * reassembly queue. 1823 * 1824 * The criteria to step up the receive buffer one notch are: 1825 * 1. the number of bytes received during the time it takes 1826 * one timestamp to be reflected back to us (the RTT); 1827 * 2. received bytes per RTT is within seven eighth of the 1828 * current socket buffer size; 1829 * 3. receive buffer size has not hit maximal automatic size; 1830 * 1831 * This algorithm does one step per RTT at most and only if 1832 * we receive a bulk stream w/o packet losses or reorderings. 1833 * Shrinking the buffer during idle times is not necessary as 1834 * it doesn't consume any memory when idle. 1835 * 1836 * TODO: Only step up if the application is actually serving 1837 * the buffer to better manage the socket buffer resources. 1838 */ 1839 if (tcp_do_autorcvbuf && 1840 opti.ts_ecr && 1841 (so->so_rcv.sb_flags & SB_AUTOSIZE)) { 1842 if (opti.ts_ecr > tp->rfbuf_ts && 1843 opti.ts_ecr - tp->rfbuf_ts < PR_SLOWHZ) { 1844 if (tp->rfbuf_cnt > 1845 (so->so_rcv.sb_hiwat / 8 * 7) && 1846 so->so_rcv.sb_hiwat < 1847 tcp_autorcvbuf_max) { 1848 newsize = 1849 min(so->so_rcv.sb_hiwat + 1850 tcp_autorcvbuf_inc, 1851 tcp_autorcvbuf_max); 1852 } 1853 /* Start over with next RTT. */ 1854 tp->rfbuf_ts = 0; 1855 tp->rfbuf_cnt = 0; 1856 } else 1857 tp->rfbuf_cnt += tlen; /* add up */ 1858 } 1859 1860 /* 1861 * Drop TCP, IP headers and TCP options then add data 1862 * to socket buffer. 1863 */ 1864 if (so->so_state & SS_CANTRCVMORE) 1865 m_freem(m); 1866 else { 1867 /* 1868 * Set new socket buffer size. 1869 * Give up when limit is reached. 1870 */ 1871 if (newsize) 1872 if (!sbreserve(&so->so_rcv, 1873 newsize, so)) 1874 so->so_rcv.sb_flags &= ~SB_AUTOSIZE; 1875 m_adj(m, toff + off); 1876 sbappendstream(&so->so_rcv, m); 1877 } 1878 sorwakeup(so); 1879 tcp_setup_ack(tp, th); 1880 if (tp->t_flags & TF_ACKNOW) 1881 (void) tcp_output(tp); 1882 if (tcp_saveti) 1883 m_freem(tcp_saveti); 1884 return; 1885 } 1886 } 1887 1888 /* 1889 * Compute mbuf offset to TCP data segment. 1890 */ 1891 hdroptlen = toff + off; 1892 1893 /* 1894 * Calculate amount of space in receive window, 1895 * and then do TCP input processing. 1896 * Receive window is amount of space in rcv queue, 1897 * but not less than advertised window. 1898 */ 1899 { int win; 1900 1901 win = sbspace(&so->so_rcv); 1902 if (win < 0) 1903 win = 0; 1904 tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt)); 1905 } 1906 1907 /* Reset receive buffer auto scaling when not in bulk receive mode. */ 1908 tp->rfbuf_ts = 0; 1909 tp->rfbuf_cnt = 0; 1910 1911 switch (tp->t_state) { 1912 /* 1913 * If the state is SYN_SENT: 1914 * if seg contains an ACK, but not for our SYN, drop the input. 1915 * if seg contains a RST, then drop the connection. 1916 * if seg does not contain SYN, then drop it. 1917 * Otherwise this is an acceptable SYN segment 1918 * initialize tp->rcv_nxt and tp->irs 1919 * if seg contains ack then advance tp->snd_una 1920 * if seg contains a ECE and ECN support is enabled, the stream 1921 * is ECN capable. 1922 * if SYN has been acked change to ESTABLISHED else SYN_RCVD state 1923 * arrange for segment to be acked (eventually) 1924 * continue processing rest of data/controls, beginning with URG 1925 */ 1926 case TCPS_SYN_SENT: 1927 if ((tiflags & TH_ACK) && 1928 (SEQ_LEQ(th->th_ack, tp->iss) || 1929 SEQ_GT(th->th_ack, tp->snd_max))) 1930 goto dropwithreset; 1931 if (tiflags & TH_RST) { 1932 if (tiflags & TH_ACK) 1933 tp = tcp_drop(tp, ECONNREFUSED); 1934 goto drop; 1935 } 1936 if ((tiflags & TH_SYN) == 0) 1937 goto drop; 1938 if (tiflags & TH_ACK) { 1939 tp->snd_una = th->th_ack; 1940 if (SEQ_LT(tp->snd_nxt, tp->snd_una)) 1941 tp->snd_nxt = tp->snd_una; 1942 if (SEQ_LT(tp->snd_high, tp->snd_una)) 1943 tp->snd_high = tp->snd_una; 1944 TCP_TIMER_DISARM(tp, TCPT_REXMT); 1945 1946 if ((tiflags & TH_ECE) && tcp_do_ecn) { 1947 tp->t_flags |= TF_ECN_PERMIT; 1948 TCP_STATINC(TCP_STAT_ECN_SHS); 1949 } 1950 1951 } 1952 tp->irs = th->th_seq; 1953 tcp_rcvseqinit(tp); 1954 tp->t_flags |= TF_ACKNOW; 1955 tcp_mss_from_peer(tp, opti.maxseg); 1956 1957 /* 1958 * Initialize the initial congestion window. If we 1959 * had to retransmit the SYN, we must initialize cwnd 1960 * to 1 segment (i.e. the Loss Window). 1961 */ 1962 if (tp->t_flags & TF_SYN_REXMT) 1963 tp->snd_cwnd = tp->t_peermss; 1964 else { 1965 int ss = tcp_init_win; 1966 #ifdef INET 1967 if (inp != NULL && in_localaddr(inp->inp_faddr)) 1968 ss = tcp_init_win_local; 1969 #endif 1970 #ifdef INET6 1971 if (in6p != NULL && in6_localaddr(&in6p->in6p_faddr)) 1972 ss = tcp_init_win_local; 1973 #endif 1974 tp->snd_cwnd = TCP_INITIAL_WINDOW(ss, tp->t_peermss); 1975 } 1976 1977 tcp_rmx_rtt(tp); 1978 if (tiflags & TH_ACK) { 1979 TCP_STATINC(TCP_STAT_CONNECTS); 1980 soisconnected(so); 1981 tcp_established(tp); 1982 /* Do window scaling on this connection? */ 1983 if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == 1984 (TF_RCVD_SCALE|TF_REQ_SCALE)) { 1985 tp->snd_scale = tp->requested_s_scale; 1986 tp->rcv_scale = tp->request_r_scale; 1987 } 1988 TCP_REASS_LOCK(tp); 1989 (void) tcp_reass(tp, NULL, (struct mbuf *)0, &tlen); 1990 TCP_REASS_UNLOCK(tp); 1991 /* 1992 * if we didn't have to retransmit the SYN, 1993 * use its rtt as our initial srtt & rtt var. 1994 */ 1995 if (tp->t_rtttime) 1996 tcp_xmit_timer(tp, tcp_now - tp->t_rtttime); 1997 } else 1998 tp->t_state = TCPS_SYN_RECEIVED; 1999 2000 /* 2001 * Advance th->th_seq to correspond to first data byte. 2002 * If data, trim to stay within window, 2003 * dropping FIN if necessary. 2004 */ 2005 th->th_seq++; 2006 if (tlen > tp->rcv_wnd) { 2007 todrop = tlen - tp->rcv_wnd; 2008 m_adj(m, -todrop); 2009 tlen = tp->rcv_wnd; 2010 tiflags &= ~TH_FIN; 2011 tcps = TCP_STAT_GETREF(); 2012 tcps[TCP_STAT_RCVPACKAFTERWIN]++; 2013 tcps[TCP_STAT_RCVBYTEAFTERWIN] += todrop; 2014 TCP_STAT_PUTREF(); 2015 } 2016 tp->snd_wl1 = th->th_seq - 1; 2017 tp->rcv_up = th->th_seq; 2018 goto step6; 2019 2020 /* 2021 * If the state is SYN_RECEIVED: 2022 * If seg contains an ACK, but not for our SYN, drop the input 2023 * and generate an RST. See page 36, rfc793 2024 */ 2025 case TCPS_SYN_RECEIVED: 2026 if ((tiflags & TH_ACK) && 2027 (SEQ_LEQ(th->th_ack, tp->iss) || 2028 SEQ_GT(th->th_ack, tp->snd_max))) 2029 goto dropwithreset; 2030 break; 2031 } 2032 2033 /* 2034 * States other than LISTEN or SYN_SENT. 2035 * First check timestamp, if present. 2036 * Then check that at least some bytes of segment are within 2037 * receive window. If segment begins before rcv_nxt, 2038 * drop leading data (and SYN); if nothing left, just ack. 2039 * 2040 * RFC 1323 PAWS: If we have a timestamp reply on this segment 2041 * and it's less than ts_recent, drop it. 2042 */ 2043 if (opti.ts_present && (tiflags & TH_RST) == 0 && tp->ts_recent && 2044 TSTMP_LT(opti.ts_val, tp->ts_recent)) { 2045 2046 /* Check to see if ts_recent is over 24 days old. */ 2047 if (tcp_now - tp->ts_recent_age > TCP_PAWS_IDLE) { 2048 /* 2049 * Invalidate ts_recent. If this segment updates 2050 * ts_recent, the age will be reset later and ts_recent 2051 * will get a valid value. If it does not, setting 2052 * ts_recent to zero will at least satisfy the 2053 * requirement that zero be placed in the timestamp 2054 * echo reply when ts_recent isn't valid. The 2055 * age isn't reset until we get a valid ts_recent 2056 * because we don't want out-of-order segments to be 2057 * dropped when ts_recent is old. 2058 */ 2059 tp->ts_recent = 0; 2060 } else { 2061 tcps = TCP_STAT_GETREF(); 2062 tcps[TCP_STAT_RCVDUPPACK]++; 2063 tcps[TCP_STAT_RCVDUPBYTE] += tlen; 2064 tcps[TCP_STAT_PAWSDROP]++; 2065 TCP_STAT_PUTREF(); 2066 tcp_new_dsack(tp, th->th_seq, tlen); 2067 goto dropafterack; 2068 } 2069 } 2070 2071 todrop = tp->rcv_nxt - th->th_seq; 2072 dupseg = false; 2073 if (todrop > 0) { 2074 if (tiflags & TH_SYN) { 2075 tiflags &= ~TH_SYN; 2076 th->th_seq++; 2077 if (th->th_urp > 1) 2078 th->th_urp--; 2079 else { 2080 tiflags &= ~TH_URG; 2081 th->th_urp = 0; 2082 } 2083 todrop--; 2084 } 2085 if (todrop > tlen || 2086 (todrop == tlen && (tiflags & TH_FIN) == 0)) { 2087 /* 2088 * Any valid FIN or RST must be to the left of the 2089 * window. At this point the FIN or RST must be a 2090 * duplicate or out of sequence; drop it. 2091 */ 2092 if (tiflags & TH_RST) 2093 goto drop; 2094 tiflags &= ~(TH_FIN|TH_RST); 2095 /* 2096 * Send an ACK to resynchronize and drop any data. 2097 * But keep on processing for RST or ACK. 2098 */ 2099 tp->t_flags |= TF_ACKNOW; 2100 todrop = tlen; 2101 dupseg = true; 2102 tcps = TCP_STAT_GETREF(); 2103 tcps[TCP_STAT_RCVDUPPACK]++; 2104 tcps[TCP_STAT_RCVDUPBYTE] += todrop; 2105 TCP_STAT_PUTREF(); 2106 } else if ((tiflags & TH_RST) && 2107 th->th_seq != tp->last_ack_sent) { 2108 /* 2109 * Test for reset before adjusting the sequence 2110 * number for overlapping data. 2111 */ 2112 goto dropafterack_ratelim; 2113 } else { 2114 tcps = TCP_STAT_GETREF(); 2115 tcps[TCP_STAT_RCVPARTDUPPACK]++; 2116 tcps[TCP_STAT_RCVPARTDUPBYTE] += todrop; 2117 TCP_STAT_PUTREF(); 2118 } 2119 tcp_new_dsack(tp, th->th_seq, todrop); 2120 hdroptlen += todrop; /*drop from head afterwards*/ 2121 th->th_seq += todrop; 2122 tlen -= todrop; 2123 if (th->th_urp > todrop) 2124 th->th_urp -= todrop; 2125 else { 2126 tiflags &= ~TH_URG; 2127 th->th_urp = 0; 2128 } 2129 } 2130 2131 /* 2132 * If new data are received on a connection after the 2133 * user processes are gone, then RST the other end. 2134 */ 2135 if ((so->so_state & SS_NOFDREF) && 2136 tp->t_state > TCPS_CLOSE_WAIT && tlen) { 2137 tp = tcp_close(tp); 2138 TCP_STATINC(TCP_STAT_RCVAFTERCLOSE); 2139 goto dropwithreset; 2140 } 2141 2142 /* 2143 * If segment ends after window, drop trailing data 2144 * (and PUSH and FIN); if nothing left, just ACK. 2145 */ 2146 todrop = (th->th_seq + tlen) - (tp->rcv_nxt+tp->rcv_wnd); 2147 if (todrop > 0) { 2148 TCP_STATINC(TCP_STAT_RCVPACKAFTERWIN); 2149 if (todrop >= tlen) { 2150 /* 2151 * The segment actually starts after the window. 2152 * th->th_seq + tlen - tp->rcv_nxt - tp->rcv_wnd >= tlen 2153 * th->th_seq - tp->rcv_nxt - tp->rcv_wnd >= 0 2154 * th->th_seq >= tp->rcv_nxt + tp->rcv_wnd 2155 */ 2156 TCP_STATADD(TCP_STAT_RCVBYTEAFTERWIN, tlen); 2157 /* 2158 * If a new connection request is received 2159 * while in TIME_WAIT, drop the old connection 2160 * and start over if the sequence numbers 2161 * are above the previous ones. 2162 * 2163 * NOTE: We will checksum the packet again, and 2164 * so we need to put the header fields back into 2165 * network order! 2166 * XXX This kind of sucks, but we don't expect 2167 * XXX this to happen very often, so maybe it 2168 * XXX doesn't matter so much. 2169 */ 2170 if (tiflags & TH_SYN && 2171 tp->t_state == TCPS_TIME_WAIT && 2172 SEQ_GT(th->th_seq, tp->rcv_nxt)) { 2173 tp = tcp_close(tp); 2174 tcp_fields_to_net(th); 2175 goto findpcb; 2176 } 2177 /* 2178 * If window is closed can only take segments at 2179 * window edge, and have to drop data and PUSH from 2180 * incoming segments. Continue processing, but 2181 * remember to ack. Otherwise, drop segment 2182 * and (if not RST) ack. 2183 */ 2184 if (tp->rcv_wnd == 0 && th->th_seq == tp->rcv_nxt) { 2185 tp->t_flags |= TF_ACKNOW; 2186 TCP_STATINC(TCP_STAT_RCVWINPROBE); 2187 } else 2188 goto dropafterack; 2189 } else 2190 TCP_STATADD(TCP_STAT_RCVBYTEAFTERWIN, todrop); 2191 m_adj(m, -todrop); 2192 tlen -= todrop; 2193 tiflags &= ~(TH_PUSH|TH_FIN); 2194 } 2195 2196 /* 2197 * If last ACK falls within this segment's sequence numbers, 2198 * record the timestamp. 2199 * NOTE: 2200 * 1) That the test incorporates suggestions from the latest 2201 * proposal of the tcplw@cray.com list (Braden 1993/04/26). 2202 * 2) That updating only on newer timestamps interferes with 2203 * our earlier PAWS tests, so this check should be solely 2204 * predicated on the sequence space of this segment. 2205 * 3) That we modify the segment boundary check to be 2206 * Last.ACK.Sent <= SEG.SEQ + SEG.Len 2207 * instead of RFC1323's 2208 * Last.ACK.Sent < SEG.SEQ + SEG.Len, 2209 * This modified check allows us to overcome RFC1323's 2210 * limitations as described in Stevens TCP/IP Illustrated 2211 * Vol. 2 p.869. In such cases, we can still calculate the 2212 * RTT correctly when RCV.NXT == Last.ACK.Sent. 2213 */ 2214 if (opti.ts_present && 2215 SEQ_LEQ(th->th_seq, tp->last_ack_sent) && 2216 SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + 2217 ((tiflags & (TH_SYN|TH_FIN)) != 0))) { 2218 tp->ts_recent_age = tcp_now; 2219 tp->ts_recent = opti.ts_val; 2220 } 2221 2222 /* 2223 * If the RST bit is set examine the state: 2224 * SYN_RECEIVED STATE: 2225 * If passive open, return to LISTEN state. 2226 * If active open, inform user that connection was refused. 2227 * ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES: 2228 * Inform user that connection was reset, and close tcb. 2229 * CLOSING, LAST_ACK, TIME_WAIT STATES 2230 * Close the tcb. 2231 */ 2232 if (tiflags & TH_RST) { 2233 if (th->th_seq != tp->last_ack_sent) 2234 goto dropafterack_ratelim; 2235 2236 switch (tp->t_state) { 2237 case TCPS_SYN_RECEIVED: 2238 so->so_error = ECONNREFUSED; 2239 goto close; 2240 2241 case TCPS_ESTABLISHED: 2242 case TCPS_FIN_WAIT_1: 2243 case TCPS_FIN_WAIT_2: 2244 case TCPS_CLOSE_WAIT: 2245 so->so_error = ECONNRESET; 2246 close: 2247 tp->t_state = TCPS_CLOSED; 2248 TCP_STATINC(TCP_STAT_DROPS); 2249 tp = tcp_close(tp); 2250 goto drop; 2251 2252 case TCPS_CLOSING: 2253 case TCPS_LAST_ACK: 2254 case TCPS_TIME_WAIT: 2255 tp = tcp_close(tp); 2256 goto drop; 2257 } 2258 } 2259 2260 /* 2261 * Since we've covered the SYN-SENT and SYN-RECEIVED states above 2262 * we must be in a synchronized state. RFC791 states (under RST 2263 * generation) that any unacceptable segment (an out-of-order SYN 2264 * qualifies) received in a synchronized state must elicit only an 2265 * empty acknowledgment segment ... and the connection remains in 2266 * the same state. 2267 */ 2268 if (tiflags & TH_SYN) { 2269 if (tp->rcv_nxt == th->th_seq) { 2270 tcp_respond(tp, m, m, th, (tcp_seq)0, th->th_ack - 1, 2271 TH_ACK); 2272 if (tcp_saveti) 2273 m_freem(tcp_saveti); 2274 return; 2275 } 2276 2277 goto dropafterack_ratelim; 2278 } 2279 2280 /* 2281 * If the ACK bit is off we drop the segment and return. 2282 */ 2283 if ((tiflags & TH_ACK) == 0) { 2284 if (tp->t_flags & TF_ACKNOW) 2285 goto dropafterack; 2286 else 2287 goto drop; 2288 } 2289 2290 /* 2291 * Ack processing. 2292 */ 2293 switch (tp->t_state) { 2294 2295 /* 2296 * In SYN_RECEIVED state if the ack ACKs our SYN then enter 2297 * ESTABLISHED state and continue processing, otherwise 2298 * send an RST. 2299 */ 2300 case TCPS_SYN_RECEIVED: 2301 if (SEQ_GT(tp->snd_una, th->th_ack) || 2302 SEQ_GT(th->th_ack, tp->snd_max)) 2303 goto dropwithreset; 2304 TCP_STATINC(TCP_STAT_CONNECTS); 2305 soisconnected(so); 2306 tcp_established(tp); 2307 /* Do window scaling? */ 2308 if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == 2309 (TF_RCVD_SCALE|TF_REQ_SCALE)) { 2310 tp->snd_scale = tp->requested_s_scale; 2311 tp->rcv_scale = tp->request_r_scale; 2312 } 2313 TCP_REASS_LOCK(tp); 2314 (void) tcp_reass(tp, NULL, (struct mbuf *)0, &tlen); 2315 TCP_REASS_UNLOCK(tp); 2316 tp->snd_wl1 = th->th_seq - 1; 2317 /* fall into ... */ 2318 2319 /* 2320 * In ESTABLISHED state: drop duplicate ACKs; ACK out of range 2321 * ACKs. If the ack is in the range 2322 * tp->snd_una < th->th_ack <= tp->snd_max 2323 * then advance tp->snd_una to th->th_ack and drop 2324 * data from the retransmission queue. If this ACK reflects 2325 * more up to date window information we update our window information. 2326 */ 2327 case TCPS_ESTABLISHED: 2328 case TCPS_FIN_WAIT_1: 2329 case TCPS_FIN_WAIT_2: 2330 case TCPS_CLOSE_WAIT: 2331 case TCPS_CLOSING: 2332 case TCPS_LAST_ACK: 2333 case TCPS_TIME_WAIT: 2334 2335 if (SEQ_LEQ(th->th_ack, tp->snd_una)) { 2336 if (tlen == 0 && !dupseg && tiwin == tp->snd_wnd) { 2337 TCP_STATINC(TCP_STAT_RCVDUPPACK); 2338 /* 2339 * If we have outstanding data (other than 2340 * a window probe), this is a completely 2341 * duplicate ack (ie, window info didn't 2342 * change), the ack is the biggest we've 2343 * seen and we've seen exactly our rexmt 2344 * threshhold of them, assume a packet 2345 * has been dropped and retransmit it. 2346 * Kludge snd_nxt & the congestion 2347 * window so we send only this one 2348 * packet. 2349 */ 2350 if (TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0 || 2351 th->th_ack != tp->snd_una) 2352 tp->t_dupacks = 0; 2353 else if (tp->t_partialacks < 0 && 2354 (++tp->t_dupacks == tcprexmtthresh || 2355 TCP_FACK_FASTRECOV(tp))) { 2356 /* 2357 * Do the fast retransmit, and adjust 2358 * congestion control paramenters. 2359 */ 2360 if (tp->t_congctl->fast_retransmit(tp, th)) { 2361 /* False fast retransmit */ 2362 break; 2363 } else 2364 goto drop; 2365 } else if (tp->t_dupacks > tcprexmtthresh) { 2366 tp->snd_cwnd += tp->t_segsz; 2367 (void) tcp_output(tp); 2368 goto drop; 2369 } 2370 } else { 2371 /* 2372 * If the ack appears to be very old, only 2373 * allow data that is in-sequence. This 2374 * makes it somewhat more difficult to insert 2375 * forged data by guessing sequence numbers. 2376 * Sent an ack to try to update the send 2377 * sequence number on the other side. 2378 */ 2379 if (tlen && th->th_seq != tp->rcv_nxt && 2380 SEQ_LT(th->th_ack, 2381 tp->snd_una - tp->max_sndwnd)) 2382 goto dropafterack; 2383 } 2384 break; 2385 } 2386 /* 2387 * If the congestion window was inflated to account 2388 * for the other side's cached packets, retract it. 2389 */ 2390 /* XXX: make SACK have his own congestion control 2391 * struct -- rpaulo */ 2392 if (TCP_SACK_ENABLED(tp)) 2393 tcp_sack_newack(tp, th); 2394 else 2395 tp->t_congctl->fast_retransmit_newack(tp, th); 2396 if (SEQ_GT(th->th_ack, tp->snd_max)) { 2397 TCP_STATINC(TCP_STAT_RCVACKTOOMUCH); 2398 goto dropafterack; 2399 } 2400 acked = th->th_ack - tp->snd_una; 2401 tcps = TCP_STAT_GETREF(); 2402 tcps[TCP_STAT_RCVACKPACK]++; 2403 tcps[TCP_STAT_RCVACKBYTE] += acked; 2404 TCP_STAT_PUTREF(); 2405 2406 /* 2407 * If we have a timestamp reply, update smoothed 2408 * round trip time. If no timestamp is present but 2409 * transmit timer is running and timed sequence 2410 * number was acked, update smoothed round trip time. 2411 * Since we now have an rtt measurement, cancel the 2412 * timer backoff (cf., Phil Karn's retransmit alg.). 2413 * Recompute the initial retransmit timer. 2414 */ 2415 if (ts_rtt) 2416 tcp_xmit_timer(tp, ts_rtt); 2417 else if (tp->t_rtttime && SEQ_GT(th->th_ack, tp->t_rtseq)) 2418 tcp_xmit_timer(tp, tcp_now - tp->t_rtttime); 2419 2420 /* 2421 * If all outstanding data is acked, stop retransmit 2422 * timer and remember to restart (more output or persist). 2423 * If there is more data to be acked, restart retransmit 2424 * timer, using current (possibly backed-off) value. 2425 */ 2426 if (th->th_ack == tp->snd_max) { 2427 TCP_TIMER_DISARM(tp, TCPT_REXMT); 2428 needoutput = 1; 2429 } else if (TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) 2430 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 2431 2432 /* 2433 * New data has been acked, adjust the congestion window. 2434 */ 2435 tp->t_congctl->newack(tp, th); 2436 2437 nd6_hint(tp); 2438 if (acked > so->so_snd.sb_cc) { 2439 tp->snd_wnd -= so->so_snd.sb_cc; 2440 sbdrop(&so->so_snd, (int)so->so_snd.sb_cc); 2441 ourfinisacked = 1; 2442 } else { 2443 if (acked > (tp->t_lastoff - tp->t_inoff)) 2444 tp->t_lastm = NULL; 2445 sbdrop(&so->so_snd, acked); 2446 tp->t_lastoff -= acked; 2447 tp->snd_wnd -= acked; 2448 ourfinisacked = 0; 2449 } 2450 sowwakeup(so); 2451 2452 icmp_check(tp, th, acked); 2453 2454 tp->snd_una = th->th_ack; 2455 if (SEQ_GT(tp->snd_una, tp->snd_fack)) 2456 tp->snd_fack = tp->snd_una; 2457 if (SEQ_LT(tp->snd_nxt, tp->snd_una)) 2458 tp->snd_nxt = tp->snd_una; 2459 if (SEQ_LT(tp->snd_high, tp->snd_una)) 2460 tp->snd_high = tp->snd_una; 2461 2462 switch (tp->t_state) { 2463 2464 /* 2465 * In FIN_WAIT_1 STATE in addition to the processing 2466 * for the ESTABLISHED state if our FIN is now acknowledged 2467 * then enter FIN_WAIT_2. 2468 */ 2469 case TCPS_FIN_WAIT_1: 2470 if (ourfinisacked) { 2471 /* 2472 * If we can't receive any more 2473 * data, then closing user can proceed. 2474 * Starting the timer is contrary to the 2475 * specification, but if we don't get a FIN 2476 * we'll hang forever. 2477 */ 2478 if (so->so_state & SS_CANTRCVMORE) { 2479 soisdisconnected(so); 2480 if (tp->t_maxidle > 0) 2481 TCP_TIMER_ARM(tp, TCPT_2MSL, 2482 tp->t_maxidle); 2483 } 2484 tp->t_state = TCPS_FIN_WAIT_2; 2485 } 2486 break; 2487 2488 /* 2489 * In CLOSING STATE in addition to the processing for 2490 * the ESTABLISHED state if the ACK acknowledges our FIN 2491 * then enter the TIME-WAIT state, otherwise ignore 2492 * the segment. 2493 */ 2494 case TCPS_CLOSING: 2495 if (ourfinisacked) { 2496 tp->t_state = TCPS_TIME_WAIT; 2497 tcp_canceltimers(tp); 2498 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2499 soisdisconnected(so); 2500 } 2501 break; 2502 2503 /* 2504 * In LAST_ACK, we may still be waiting for data to drain 2505 * and/or to be acked, as well as for the ack of our FIN. 2506 * If our FIN is now acknowledged, delete the TCB, 2507 * enter the closed state and return. 2508 */ 2509 case TCPS_LAST_ACK: 2510 if (ourfinisacked) { 2511 tp = tcp_close(tp); 2512 goto drop; 2513 } 2514 break; 2515 2516 /* 2517 * In TIME_WAIT state the only thing that should arrive 2518 * is a retransmission of the remote FIN. Acknowledge 2519 * it and restart the finack timer. 2520 */ 2521 case TCPS_TIME_WAIT: 2522 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2523 goto dropafterack; 2524 } 2525 } 2526 2527 step6: 2528 /* 2529 * Update window information. 2530 * Don't look at window if no ACK: TAC's send garbage on first SYN. 2531 */ 2532 if ((tiflags & TH_ACK) && (SEQ_LT(tp->snd_wl1, th->th_seq) || 2533 (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) || 2534 (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) { 2535 /* keep track of pure window updates */ 2536 if (tlen == 0 && 2537 tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd) 2538 TCP_STATINC(TCP_STAT_RCVWINUPD); 2539 tp->snd_wnd = tiwin; 2540 tp->snd_wl1 = th->th_seq; 2541 tp->snd_wl2 = th->th_ack; 2542 if (tp->snd_wnd > tp->max_sndwnd) 2543 tp->max_sndwnd = tp->snd_wnd; 2544 needoutput = 1; 2545 } 2546 2547 /* 2548 * Process segments with URG. 2549 */ 2550 if ((tiflags & TH_URG) && th->th_urp && 2551 TCPS_HAVERCVDFIN(tp->t_state) == 0) { 2552 /* 2553 * This is a kludge, but if we receive and accept 2554 * random urgent pointers, we'll crash in 2555 * soreceive. It's hard to imagine someone 2556 * actually wanting to send this much urgent data. 2557 */ 2558 if (th->th_urp + so->so_rcv.sb_cc > sb_max) { 2559 th->th_urp = 0; /* XXX */ 2560 tiflags &= ~TH_URG; /* XXX */ 2561 goto dodata; /* XXX */ 2562 } 2563 /* 2564 * If this segment advances the known urgent pointer, 2565 * then mark the data stream. This should not happen 2566 * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since 2567 * a FIN has been received from the remote side. 2568 * In these states we ignore the URG. 2569 * 2570 * According to RFC961 (Assigned Protocols), 2571 * the urgent pointer points to the last octet 2572 * of urgent data. We continue, however, 2573 * to consider it to indicate the first octet 2574 * of data past the urgent section as the original 2575 * spec states (in one of two places). 2576 */ 2577 if (SEQ_GT(th->th_seq+th->th_urp, tp->rcv_up)) { 2578 tp->rcv_up = th->th_seq + th->th_urp; 2579 so->so_oobmark = so->so_rcv.sb_cc + 2580 (tp->rcv_up - tp->rcv_nxt) - 1; 2581 if (so->so_oobmark == 0) 2582 so->so_state |= SS_RCVATMARK; 2583 sohasoutofband(so); 2584 tp->t_oobflags &= ~(TCPOOB_HAVEDATA | TCPOOB_HADDATA); 2585 } 2586 /* 2587 * Remove out of band data so doesn't get presented to user. 2588 * This can happen independent of advancing the URG pointer, 2589 * but if two URG's are pending at once, some out-of-band 2590 * data may creep in... ick. 2591 */ 2592 if (th->th_urp <= (u_int16_t) tlen 2593 #ifdef SO_OOBINLINE 2594 && (so->so_options & SO_OOBINLINE) == 0 2595 #endif 2596 ) 2597 tcp_pulloutofband(so, th, m, hdroptlen); 2598 } else 2599 /* 2600 * If no out of band data is expected, 2601 * pull receive urgent pointer along 2602 * with the receive window. 2603 */ 2604 if (SEQ_GT(tp->rcv_nxt, tp->rcv_up)) 2605 tp->rcv_up = tp->rcv_nxt; 2606 dodata: /* XXX */ 2607 2608 /* 2609 * Process the segment text, merging it into the TCP sequencing queue, 2610 * and arranging for acknowledgement of receipt if necessary. 2611 * This process logically involves adjusting tp->rcv_wnd as data 2612 * is presented to the user (this happens in tcp_usrreq.c, 2613 * case PRU_RCVD). If a FIN has already been received on this 2614 * connection then we just ignore the text. 2615 */ 2616 if ((tlen || (tiflags & TH_FIN)) && 2617 TCPS_HAVERCVDFIN(tp->t_state) == 0) { 2618 /* 2619 * Insert segment ti into reassembly queue of tcp with 2620 * control block tp. Return TH_FIN if reassembly now includes 2621 * a segment with FIN. The macro form does the common case 2622 * inline (segment is the next to be received on an 2623 * established connection, and the queue is empty), 2624 * avoiding linkage into and removal from the queue and 2625 * repetition of various conversions. 2626 * Set DELACK for segments received in order, but ack 2627 * immediately when segments are out of order 2628 * (so fast retransmit can work). 2629 */ 2630 /* NOTE: this was TCP_REASS() macro, but used only once */ 2631 TCP_REASS_LOCK(tp); 2632 if (th->th_seq == tp->rcv_nxt && 2633 TAILQ_FIRST(&tp->segq) == NULL && 2634 tp->t_state == TCPS_ESTABLISHED) { 2635 tcp_setup_ack(tp, th); 2636 tp->rcv_nxt += tlen; 2637 tiflags = th->th_flags & TH_FIN; 2638 tcps = TCP_STAT_GETREF(); 2639 tcps[TCP_STAT_RCVPACK]++; 2640 tcps[TCP_STAT_RCVBYTE] += tlen; 2641 TCP_STAT_PUTREF(); 2642 nd6_hint(tp); 2643 if (so->so_state & SS_CANTRCVMORE) 2644 m_freem(m); 2645 else { 2646 m_adj(m, hdroptlen); 2647 sbappendstream(&(so)->so_rcv, m); 2648 } 2649 TCP_REASS_UNLOCK(tp); 2650 sorwakeup(so); 2651 } else { 2652 m_adj(m, hdroptlen); 2653 tiflags = tcp_reass(tp, th, m, &tlen); 2654 tp->t_flags |= TF_ACKNOW; 2655 TCP_REASS_UNLOCK(tp); 2656 } 2657 2658 /* 2659 * Note the amount of data that peer has sent into 2660 * our window, in order to estimate the sender's 2661 * buffer size. 2662 */ 2663 len = so->so_rcv.sb_hiwat - (tp->rcv_adv - tp->rcv_nxt); 2664 } else { 2665 m_freem(m); 2666 m = NULL; 2667 tiflags &= ~TH_FIN; 2668 } 2669 2670 /* 2671 * If FIN is received ACK the FIN and let the user know 2672 * that the connection is closing. Ignore a FIN received before 2673 * the connection is fully established. 2674 */ 2675 if ((tiflags & TH_FIN) && TCPS_HAVEESTABLISHED(tp->t_state)) { 2676 if (TCPS_HAVERCVDFIN(tp->t_state) == 0) { 2677 socantrcvmore(so); 2678 tp->t_flags |= TF_ACKNOW; 2679 tp->rcv_nxt++; 2680 } 2681 switch (tp->t_state) { 2682 2683 /* 2684 * In ESTABLISHED STATE enter the CLOSE_WAIT state. 2685 */ 2686 case TCPS_ESTABLISHED: 2687 tp->t_state = TCPS_CLOSE_WAIT; 2688 break; 2689 2690 /* 2691 * If still in FIN_WAIT_1 STATE FIN has not been acked so 2692 * enter the CLOSING state. 2693 */ 2694 case TCPS_FIN_WAIT_1: 2695 tp->t_state = TCPS_CLOSING; 2696 break; 2697 2698 /* 2699 * In FIN_WAIT_2 state enter the TIME_WAIT state, 2700 * starting the time-wait timer, turning off the other 2701 * standard timers. 2702 */ 2703 case TCPS_FIN_WAIT_2: 2704 tp->t_state = TCPS_TIME_WAIT; 2705 tcp_canceltimers(tp); 2706 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2707 soisdisconnected(so); 2708 break; 2709 2710 /* 2711 * In TIME_WAIT state restart the 2 MSL time_wait timer. 2712 */ 2713 case TCPS_TIME_WAIT: 2714 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2715 break; 2716 } 2717 } 2718 #ifdef TCP_DEBUG 2719 if (so->so_options & SO_DEBUG) 2720 tcp_trace(TA_INPUT, ostate, tp, tcp_saveti, 0); 2721 #endif 2722 2723 /* 2724 * Return any desired output. 2725 */ 2726 if (needoutput || (tp->t_flags & TF_ACKNOW)) { 2727 (void) tcp_output(tp); 2728 } 2729 if (tcp_saveti) 2730 m_freem(tcp_saveti); 2731 return; 2732 2733 badsyn: 2734 /* 2735 * Received a bad SYN. Increment counters and dropwithreset. 2736 */ 2737 TCP_STATINC(TCP_STAT_BADSYN); 2738 tp = NULL; 2739 goto dropwithreset; 2740 2741 dropafterack: 2742 /* 2743 * Generate an ACK dropping incoming segment if it occupies 2744 * sequence space, where the ACK reflects our state. 2745 */ 2746 if (tiflags & TH_RST) 2747 goto drop; 2748 goto dropafterack2; 2749 2750 dropafterack_ratelim: 2751 /* 2752 * We may want to rate-limit ACKs against SYN/RST attack. 2753 */ 2754 if (ppsratecheck(&tcp_ackdrop_ppslim_last, &tcp_ackdrop_ppslim_count, 2755 tcp_ackdrop_ppslim) == 0) { 2756 /* XXX stat */ 2757 goto drop; 2758 } 2759 /* ...fall into dropafterack2... */ 2760 2761 dropafterack2: 2762 m_freem(m); 2763 tp->t_flags |= TF_ACKNOW; 2764 (void) tcp_output(tp); 2765 if (tcp_saveti) 2766 m_freem(tcp_saveti); 2767 return; 2768 2769 dropwithreset_ratelim: 2770 /* 2771 * We may want to rate-limit RSTs in certain situations, 2772 * particularly if we are sending an RST in response to 2773 * an attempt to connect to or otherwise communicate with 2774 * a port for which we have no socket. 2775 */ 2776 if (ppsratecheck(&tcp_rst_ppslim_last, &tcp_rst_ppslim_count, 2777 tcp_rst_ppslim) == 0) { 2778 /* XXX stat */ 2779 goto drop; 2780 } 2781 /* ...fall into dropwithreset... */ 2782 2783 dropwithreset: 2784 /* 2785 * Generate a RST, dropping incoming segment. 2786 * Make ACK acceptable to originator of segment. 2787 */ 2788 if (tiflags & TH_RST) 2789 goto drop; 2790 2791 switch (af) { 2792 #ifdef INET6 2793 case AF_INET6: 2794 /* For following calls to tcp_respond */ 2795 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) 2796 goto drop; 2797 break; 2798 #endif /* INET6 */ 2799 case AF_INET: 2800 if (IN_MULTICAST(ip->ip_dst.s_addr) || 2801 in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) 2802 goto drop; 2803 } 2804 2805 if (tiflags & TH_ACK) 2806 (void)tcp_respond(tp, m, m, th, (tcp_seq)0, th->th_ack, TH_RST); 2807 else { 2808 if (tiflags & TH_SYN) 2809 tlen++; 2810 (void)tcp_respond(tp, m, m, th, th->th_seq + tlen, (tcp_seq)0, 2811 TH_RST|TH_ACK); 2812 } 2813 if (tcp_saveti) 2814 m_freem(tcp_saveti); 2815 return; 2816 2817 badcsum: 2818 drop: 2819 /* 2820 * Drop space held by incoming segment and return. 2821 */ 2822 if (tp) { 2823 if (tp->t_inpcb) 2824 so = tp->t_inpcb->inp_socket; 2825 #ifdef INET6 2826 else if (tp->t_in6pcb) 2827 so = tp->t_in6pcb->in6p_socket; 2828 #endif 2829 else 2830 so = NULL; 2831 #ifdef TCP_DEBUG 2832 if (so && (so->so_options & SO_DEBUG) != 0) 2833 tcp_trace(TA_DROP, ostate, tp, tcp_saveti, 0); 2834 #endif 2835 } 2836 if (tcp_saveti) 2837 m_freem(tcp_saveti); 2838 m_freem(m); 2839 return; 2840 } 2841 2842 #ifdef TCP_SIGNATURE 2843 int 2844 tcp_signature_apply(void *fstate, void *data, u_int len) 2845 { 2846 2847 MD5Update(fstate, (u_char *)data, len); 2848 return (0); 2849 } 2850 2851 struct secasvar * 2852 tcp_signature_getsav(struct mbuf *m, struct tcphdr *th) 2853 { 2854 struct secasvar *sav; 2855 #ifdef FAST_IPSEC 2856 union sockaddr_union dst; 2857 #endif 2858 struct ip *ip; 2859 struct ip6_hdr *ip6; 2860 2861 ip = mtod(m, struct ip *); 2862 switch (ip->ip_v) { 2863 case 4: 2864 ip = mtod(m, struct ip *); 2865 ip6 = NULL; 2866 break; 2867 case 6: 2868 ip = NULL; 2869 ip6 = mtod(m, struct ip6_hdr *); 2870 break; 2871 default: 2872 return (NULL); 2873 } 2874 2875 #ifdef FAST_IPSEC 2876 /* Extract the destination from the IP header in the mbuf. */ 2877 memset(&dst, 0, sizeof(union sockaddr_union)); 2878 if (ip !=NULL) { 2879 dst.sa.sa_len = sizeof(struct sockaddr_in); 2880 dst.sa.sa_family = AF_INET; 2881 dst.sin.sin_addr = ip->ip_dst; 2882 } else { 2883 dst.sa.sa_len = sizeof(struct sockaddr_in6); 2884 dst.sa.sa_family = AF_INET6; 2885 dst.sin6.sin6_addr = ip6->ip6_dst; 2886 } 2887 2888 /* 2889 * Look up an SADB entry which matches the address of the peer. 2890 */ 2891 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2892 #else 2893 if (ip) 2894 sav = key_allocsa(AF_INET, (void *)&ip->ip_src, 2895 (void *)&ip->ip_dst, IPPROTO_TCP, 2896 htonl(TCP_SIG_SPI), 0, 0); 2897 else 2898 sav = key_allocsa(AF_INET6, (void *)&ip6->ip6_src, 2899 (void *)&ip6->ip6_dst, IPPROTO_TCP, 2900 htonl(TCP_SIG_SPI), 0, 0); 2901 #endif 2902 2903 return (sav); /* freesav must be performed by caller */ 2904 } 2905 2906 int 2907 tcp_signature(struct mbuf *m, struct tcphdr *th, int thoff, 2908 struct secasvar *sav, char *sig) 2909 { 2910 MD5_CTX ctx; 2911 struct ip *ip; 2912 struct ipovly *ipovly; 2913 struct ip6_hdr *ip6; 2914 struct ippseudo ippseudo; 2915 struct ip6_hdr_pseudo ip6pseudo; 2916 struct tcphdr th0; 2917 int l, tcphdrlen; 2918 2919 if (sav == NULL) 2920 return (-1); 2921 2922 tcphdrlen = th->th_off * 4; 2923 2924 switch (mtod(m, struct ip *)->ip_v) { 2925 case 4: 2926 ip = mtod(m, struct ip *); 2927 ip6 = NULL; 2928 break; 2929 case 6: 2930 ip = NULL; 2931 ip6 = mtod(m, struct ip6_hdr *); 2932 break; 2933 default: 2934 return (-1); 2935 } 2936 2937 MD5Init(&ctx); 2938 2939 if (ip) { 2940 memset(&ippseudo, 0, sizeof(ippseudo)); 2941 ipovly = (struct ipovly *)ip; 2942 ippseudo.ippseudo_src = ipovly->ih_src; 2943 ippseudo.ippseudo_dst = ipovly->ih_dst; 2944 ippseudo.ippseudo_pad = 0; 2945 ippseudo.ippseudo_p = IPPROTO_TCP; 2946 ippseudo.ippseudo_len = htons(m->m_pkthdr.len - thoff); 2947 MD5Update(&ctx, (char *)&ippseudo, sizeof(ippseudo)); 2948 } else { 2949 memset(&ip6pseudo, 0, sizeof(ip6pseudo)); 2950 ip6pseudo.ip6ph_src = ip6->ip6_src; 2951 in6_clearscope(&ip6pseudo.ip6ph_src); 2952 ip6pseudo.ip6ph_dst = ip6->ip6_dst; 2953 in6_clearscope(&ip6pseudo.ip6ph_dst); 2954 ip6pseudo.ip6ph_len = htons(m->m_pkthdr.len - thoff); 2955 ip6pseudo.ip6ph_nxt = IPPROTO_TCP; 2956 MD5Update(&ctx, (char *)&ip6pseudo, sizeof(ip6pseudo)); 2957 } 2958 2959 th0 = *th; 2960 th0.th_sum = 0; 2961 MD5Update(&ctx, (char *)&th0, sizeof(th0)); 2962 2963 l = m->m_pkthdr.len - thoff - tcphdrlen; 2964 if (l > 0) 2965 m_apply(m, thoff + tcphdrlen, 2966 m->m_pkthdr.len - thoff - tcphdrlen, 2967 tcp_signature_apply, &ctx); 2968 2969 MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); 2970 MD5Final(sig, &ctx); 2971 2972 return (0); 2973 } 2974 #endif 2975 2976 static int 2977 tcp_dooptions(struct tcpcb *tp, const u_char *cp, int cnt, 2978 struct tcphdr *th, 2979 struct mbuf *m, int toff, struct tcp_opt_info *oi) 2980 { 2981 u_int16_t mss; 2982 int opt, optlen = 0; 2983 #ifdef TCP_SIGNATURE 2984 void *sigp = NULL; 2985 char sigbuf[TCP_SIGLEN]; 2986 struct secasvar *sav = NULL; 2987 #endif 2988 2989 for (; cp && cnt > 0; cnt -= optlen, cp += optlen) { 2990 opt = cp[0]; 2991 if (opt == TCPOPT_EOL) 2992 break; 2993 if (opt == TCPOPT_NOP) 2994 optlen = 1; 2995 else { 2996 if (cnt < 2) 2997 break; 2998 optlen = cp[1]; 2999 if (optlen < 2 || optlen > cnt) 3000 break; 3001 } 3002 switch (opt) { 3003 3004 default: 3005 continue; 3006 3007 case TCPOPT_MAXSEG: 3008 if (optlen != TCPOLEN_MAXSEG) 3009 continue; 3010 if (!(th->th_flags & TH_SYN)) 3011 continue; 3012 if (TCPS_HAVERCVDSYN(tp->t_state)) 3013 continue; 3014 bcopy(cp + 2, &mss, sizeof(mss)); 3015 oi->maxseg = ntohs(mss); 3016 break; 3017 3018 case TCPOPT_WINDOW: 3019 if (optlen != TCPOLEN_WINDOW) 3020 continue; 3021 if (!(th->th_flags & TH_SYN)) 3022 continue; 3023 if (TCPS_HAVERCVDSYN(tp->t_state)) 3024 continue; 3025 tp->t_flags |= TF_RCVD_SCALE; 3026 tp->requested_s_scale = cp[2]; 3027 if (tp->requested_s_scale > TCP_MAX_WINSHIFT) { 3028 #if 0 /*XXX*/ 3029 char *p; 3030 3031 if (ip) 3032 p = ntohl(ip->ip_src); 3033 #ifdef INET6 3034 else if (ip6) 3035 p = ip6_sprintf(&ip6->ip6_src); 3036 #endif 3037 else 3038 p = "(unknown)"; 3039 log(LOG_ERR, "TCP: invalid wscale %d from %s, " 3040 "assuming %d\n", 3041 tp->requested_s_scale, p, 3042 TCP_MAX_WINSHIFT); 3043 #else 3044 log(LOG_ERR, "TCP: invalid wscale %d, " 3045 "assuming %d\n", 3046 tp->requested_s_scale, 3047 TCP_MAX_WINSHIFT); 3048 #endif 3049 tp->requested_s_scale = TCP_MAX_WINSHIFT; 3050 } 3051 break; 3052 3053 case TCPOPT_TIMESTAMP: 3054 if (optlen != TCPOLEN_TIMESTAMP) 3055 continue; 3056 oi->ts_present = 1; 3057 bcopy(cp + 2, &oi->ts_val, sizeof(oi->ts_val)); 3058 NTOHL(oi->ts_val); 3059 bcopy(cp + 6, &oi->ts_ecr, sizeof(oi->ts_ecr)); 3060 NTOHL(oi->ts_ecr); 3061 3062 if (!(th->th_flags & TH_SYN)) 3063 continue; 3064 if (TCPS_HAVERCVDSYN(tp->t_state)) 3065 continue; 3066 /* 3067 * A timestamp received in a SYN makes 3068 * it ok to send timestamp requests and replies. 3069 */ 3070 tp->t_flags |= TF_RCVD_TSTMP; 3071 tp->ts_recent = oi->ts_val; 3072 tp->ts_recent_age = tcp_now; 3073 break; 3074 3075 case TCPOPT_SACK_PERMITTED: 3076 if (optlen != TCPOLEN_SACK_PERMITTED) 3077 continue; 3078 if (!(th->th_flags & TH_SYN)) 3079 continue; 3080 if (TCPS_HAVERCVDSYN(tp->t_state)) 3081 continue; 3082 if (tcp_do_sack) { 3083 tp->t_flags |= TF_SACK_PERMIT; 3084 tp->t_flags |= TF_WILL_SACK; 3085 } 3086 break; 3087 3088 case TCPOPT_SACK: 3089 tcp_sack_option(tp, th, cp, optlen); 3090 break; 3091 #ifdef TCP_SIGNATURE 3092 case TCPOPT_SIGNATURE: 3093 if (optlen != TCPOLEN_SIGNATURE) 3094 continue; 3095 if (sigp && memcmp(sigp, cp + 2, TCP_SIGLEN)) 3096 return (-1); 3097 3098 sigp = sigbuf; 3099 memcpy(sigbuf, cp + 2, TCP_SIGLEN); 3100 tp->t_flags |= TF_SIGNATURE; 3101 break; 3102 #endif 3103 } 3104 } 3105 3106 #ifdef TCP_SIGNATURE 3107 if (tp->t_flags & TF_SIGNATURE) { 3108 3109 sav = tcp_signature_getsav(m, th); 3110 3111 if (sav == NULL && tp->t_state == TCPS_LISTEN) 3112 return (-1); 3113 } 3114 3115 if ((sigp ? TF_SIGNATURE : 0) ^ (tp->t_flags & TF_SIGNATURE)) { 3116 if (sav == NULL) 3117 return (-1); 3118 #ifdef FAST_IPSEC 3119 KEY_FREESAV(&sav); 3120 #else 3121 key_freesav(sav); 3122 #endif 3123 return (-1); 3124 } 3125 3126 if (sigp) { 3127 char sig[TCP_SIGLEN]; 3128 3129 tcp_fields_to_net(th); 3130 if (tcp_signature(m, th, toff, sav, sig) < 0) { 3131 tcp_fields_to_host(th); 3132 if (sav == NULL) 3133 return (-1); 3134 #ifdef FAST_IPSEC 3135 KEY_FREESAV(&sav); 3136 #else 3137 key_freesav(sav); 3138 #endif 3139 return (-1); 3140 } 3141 tcp_fields_to_host(th); 3142 3143 if (memcmp(sig, sigp, TCP_SIGLEN)) { 3144 TCP_STATINC(TCP_STAT_BADSIG); 3145 if (sav == NULL) 3146 return (-1); 3147 #ifdef FAST_IPSEC 3148 KEY_FREESAV(&sav); 3149 #else 3150 key_freesav(sav); 3151 #endif 3152 return (-1); 3153 } else 3154 TCP_STATINC(TCP_STAT_GOODSIG); 3155 3156 key_sa_recordxfer(sav, m); 3157 #ifdef FAST_IPSEC 3158 KEY_FREESAV(&sav); 3159 #else 3160 key_freesav(sav); 3161 #endif 3162 } 3163 #endif 3164 3165 return (0); 3166 } 3167 3168 /* 3169 * Pull out of band byte out of a segment so 3170 * it doesn't appear in the user's data queue. 3171 * It is still reflected in the segment length for 3172 * sequencing purposes. 3173 */ 3174 void 3175 tcp_pulloutofband(struct socket *so, struct tcphdr *th, 3176 struct mbuf *m, int off) 3177 { 3178 int cnt = off + th->th_urp - 1; 3179 3180 while (cnt >= 0) { 3181 if (m->m_len > cnt) { 3182 char *cp = mtod(m, char *) + cnt; 3183 struct tcpcb *tp = sototcpcb(so); 3184 3185 tp->t_iobc = *cp; 3186 tp->t_oobflags |= TCPOOB_HAVEDATA; 3187 bcopy(cp+1, cp, (unsigned)(m->m_len - cnt - 1)); 3188 m->m_len--; 3189 return; 3190 } 3191 cnt -= m->m_len; 3192 m = m->m_next; 3193 if (m == 0) 3194 break; 3195 } 3196 panic("tcp_pulloutofband"); 3197 } 3198 3199 /* 3200 * Collect new round-trip time estimate 3201 * and update averages and current timeout. 3202 */ 3203 void 3204 tcp_xmit_timer(struct tcpcb *tp, uint32_t rtt) 3205 { 3206 int32_t delta; 3207 3208 TCP_STATINC(TCP_STAT_RTTUPDATED); 3209 if (tp->t_srtt != 0) { 3210 /* 3211 * srtt is stored as fixed point with 3 bits after the 3212 * binary point (i.e., scaled by 8). The following magic 3213 * is equivalent to the smoothing algorithm in rfc793 with 3214 * an alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed 3215 * point). Adjust rtt to origin 0. 3216 */ 3217 delta = (rtt << 2) - (tp->t_srtt >> TCP_RTT_SHIFT); 3218 if ((tp->t_srtt += delta) <= 0) 3219 tp->t_srtt = 1 << 2; 3220 /* 3221 * We accumulate a smoothed rtt variance (actually, a 3222 * smoothed mean difference), then set the retransmit 3223 * timer to smoothed rtt + 4 times the smoothed variance. 3224 * rttvar is stored as fixed point with 2 bits after the 3225 * binary point (scaled by 4). The following is 3226 * equivalent to rfc793 smoothing with an alpha of .75 3227 * (rttvar = rttvar*3/4 + |delta| / 4). This replaces 3228 * rfc793's wired-in beta. 3229 */ 3230 if (delta < 0) 3231 delta = -delta; 3232 delta -= (tp->t_rttvar >> TCP_RTTVAR_SHIFT); 3233 if ((tp->t_rttvar += delta) <= 0) 3234 tp->t_rttvar = 1 << 2; 3235 } else { 3236 /* 3237 * No rtt measurement yet - use the unsmoothed rtt. 3238 * Set the variance to half the rtt (so our first 3239 * retransmit happens at 3*rtt). 3240 */ 3241 tp->t_srtt = rtt << (TCP_RTT_SHIFT + 2); 3242 tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT + 2 - 1); 3243 } 3244 tp->t_rtttime = 0; 3245 tp->t_rxtshift = 0; 3246 3247 /* 3248 * the retransmit should happen at rtt + 4 * rttvar. 3249 * Because of the way we do the smoothing, srtt and rttvar 3250 * will each average +1/2 tick of bias. When we compute 3251 * the retransmit timer, we want 1/2 tick of rounding and 3252 * 1 extra tick because of +-1/2 tick uncertainty in the 3253 * firing of the timer. The bias will give us exactly the 3254 * 1.5 tick we need. But, because the bias is 3255 * statistical, we have to test that we don't drop below 3256 * the minimum feasible timer (which is 2 ticks). 3257 */ 3258 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 3259 max(tp->t_rttmin, rtt + 2), TCPTV_REXMTMAX); 3260 3261 /* 3262 * We received an ack for a packet that wasn't retransmitted; 3263 * it is probably safe to discard any error indications we've 3264 * received recently. This isn't quite right, but close enough 3265 * for now (a route might have failed after we sent a segment, 3266 * and the return path might not be symmetrical). 3267 */ 3268 tp->t_softerror = 0; 3269 } 3270 3271 3272 /* 3273 * TCP compressed state engine. Currently used to hold compressed 3274 * state for SYN_RECEIVED. 3275 */ 3276 3277 u_long syn_cache_count; 3278 u_int32_t syn_hash1, syn_hash2; 3279 3280 #define SYN_HASH(sa, sp, dp) \ 3281 ((((sa)->s_addr^syn_hash1)*(((((u_int32_t)(dp))<<16) + \ 3282 ((u_int32_t)(sp)))^syn_hash2))) 3283 #ifndef INET6 3284 #define SYN_HASHALL(hash, src, dst) \ 3285 do { \ 3286 hash = SYN_HASH(&((const struct sockaddr_in *)(src))->sin_addr, \ 3287 ((const struct sockaddr_in *)(src))->sin_port, \ 3288 ((const struct sockaddr_in *)(dst))->sin_port); \ 3289 } while (/*CONSTCOND*/ 0) 3290 #else 3291 #define SYN_HASH6(sa, sp, dp) \ 3292 ((((sa)->s6_addr32[0] ^ (sa)->s6_addr32[3] ^ syn_hash1) * \ 3293 (((((u_int32_t)(dp))<<16) + ((u_int32_t)(sp)))^syn_hash2)) \ 3294 & 0x7fffffff) 3295 3296 #define SYN_HASHALL(hash, src, dst) \ 3297 do { \ 3298 switch ((src)->sa_family) { \ 3299 case AF_INET: \ 3300 hash = SYN_HASH(&((const struct sockaddr_in *)(src))->sin_addr, \ 3301 ((const struct sockaddr_in *)(src))->sin_port, \ 3302 ((const struct sockaddr_in *)(dst))->sin_port); \ 3303 break; \ 3304 case AF_INET6: \ 3305 hash = SYN_HASH6(&((const struct sockaddr_in6 *)(src))->sin6_addr, \ 3306 ((const struct sockaddr_in6 *)(src))->sin6_port, \ 3307 ((const struct sockaddr_in6 *)(dst))->sin6_port); \ 3308 break; \ 3309 default: \ 3310 hash = 0; \ 3311 } \ 3312 } while (/*CONSTCOND*/0) 3313 #endif /* INET6 */ 3314 3315 static struct pool syn_cache_pool; 3316 3317 /* 3318 * We don't estimate RTT with SYNs, so each packet starts with the default 3319 * RTT and each timer step has a fixed timeout value. 3320 */ 3321 #define SYN_CACHE_TIMER_ARM(sc) \ 3322 do { \ 3323 TCPT_RANGESET((sc)->sc_rxtcur, \ 3324 TCPTV_SRTTDFLT * tcp_backoff[(sc)->sc_rxtshift], TCPTV_MIN, \ 3325 TCPTV_REXMTMAX); \ 3326 callout_reset(&(sc)->sc_timer, \ 3327 (sc)->sc_rxtcur * (hz / PR_SLOWHZ), syn_cache_timer, (sc)); \ 3328 } while (/*CONSTCOND*/0) 3329 3330 #define SYN_CACHE_TIMESTAMP(sc) (tcp_now - (sc)->sc_timebase) 3331 3332 static inline void 3333 syn_cache_rm(struct syn_cache *sc) 3334 { 3335 TAILQ_REMOVE(&tcp_syn_cache[sc->sc_bucketidx].sch_bucket, 3336 sc, sc_bucketq); 3337 sc->sc_tp = NULL; 3338 LIST_REMOVE(sc, sc_tpq); 3339 tcp_syn_cache[sc->sc_bucketidx].sch_length--; 3340 callout_stop(&sc->sc_timer); 3341 syn_cache_count--; 3342 } 3343 3344 static inline void 3345 syn_cache_put(struct syn_cache *sc) 3346 { 3347 if (sc->sc_ipopts) 3348 (void) m_free(sc->sc_ipopts); 3349 rtcache_free(&sc->sc_route); 3350 if (callout_invoking(&sc->sc_timer)) 3351 sc->sc_flags |= SCF_DEAD; 3352 else { 3353 callout_destroy(&sc->sc_timer); 3354 pool_put(&syn_cache_pool, sc); 3355 } 3356 } 3357 3358 void 3359 syn_cache_init(void) 3360 { 3361 int i; 3362 3363 pool_init(&syn_cache_pool, sizeof(struct syn_cache), 0, 0, 0, 3364 "synpl", NULL, IPL_SOFTNET); 3365 3366 /* Initialize the hash buckets. */ 3367 for (i = 0; i < tcp_syn_cache_size; i++) 3368 TAILQ_INIT(&tcp_syn_cache[i].sch_bucket); 3369 } 3370 3371 void 3372 syn_cache_insert(struct syn_cache *sc, struct tcpcb *tp) 3373 { 3374 struct syn_cache_head *scp; 3375 struct syn_cache *sc2; 3376 int s; 3377 3378 /* 3379 * If there are no entries in the hash table, reinitialize 3380 * the hash secrets. 3381 */ 3382 if (syn_cache_count == 0) { 3383 syn_hash1 = arc4random(); 3384 syn_hash2 = arc4random(); 3385 } 3386 3387 SYN_HASHALL(sc->sc_hash, &sc->sc_src.sa, &sc->sc_dst.sa); 3388 sc->sc_bucketidx = sc->sc_hash % tcp_syn_cache_size; 3389 scp = &tcp_syn_cache[sc->sc_bucketidx]; 3390 3391 /* 3392 * Make sure that we don't overflow the per-bucket 3393 * limit or the total cache size limit. 3394 */ 3395 s = splsoftnet(); 3396 if (scp->sch_length >= tcp_syn_bucket_limit) { 3397 TCP_STATINC(TCP_STAT_SC_BUCKETOVERFLOW); 3398 /* 3399 * The bucket is full. Toss the oldest element in the 3400 * bucket. This will be the first entry in the bucket. 3401 */ 3402 sc2 = TAILQ_FIRST(&scp->sch_bucket); 3403 #ifdef DIAGNOSTIC 3404 /* 3405 * This should never happen; we should always find an 3406 * entry in our bucket. 3407 */ 3408 if (sc2 == NULL) 3409 panic("syn_cache_insert: bucketoverflow: impossible"); 3410 #endif 3411 syn_cache_rm(sc2); 3412 syn_cache_put(sc2); /* calls pool_put but see spl above */ 3413 } else if (syn_cache_count >= tcp_syn_cache_limit) { 3414 struct syn_cache_head *scp2, *sce; 3415 3416 TCP_STATINC(TCP_STAT_SC_OVERFLOWED); 3417 /* 3418 * The cache is full. Toss the oldest entry in the 3419 * first non-empty bucket we can find. 3420 * 3421 * XXX We would really like to toss the oldest 3422 * entry in the cache, but we hope that this 3423 * condition doesn't happen very often. 3424 */ 3425 scp2 = scp; 3426 if (TAILQ_EMPTY(&scp2->sch_bucket)) { 3427 sce = &tcp_syn_cache[tcp_syn_cache_size]; 3428 for (++scp2; scp2 != scp; scp2++) { 3429 if (scp2 >= sce) 3430 scp2 = &tcp_syn_cache[0]; 3431 if (! TAILQ_EMPTY(&scp2->sch_bucket)) 3432 break; 3433 } 3434 #ifdef DIAGNOSTIC 3435 /* 3436 * This should never happen; we should always find a 3437 * non-empty bucket. 3438 */ 3439 if (scp2 == scp) 3440 panic("syn_cache_insert: cacheoverflow: " 3441 "impossible"); 3442 #endif 3443 } 3444 sc2 = TAILQ_FIRST(&scp2->sch_bucket); 3445 syn_cache_rm(sc2); 3446 syn_cache_put(sc2); /* calls pool_put but see spl above */ 3447 } 3448 3449 /* 3450 * Initialize the entry's timer. 3451 */ 3452 sc->sc_rxttot = 0; 3453 sc->sc_rxtshift = 0; 3454 SYN_CACHE_TIMER_ARM(sc); 3455 3456 /* Link it from tcpcb entry */ 3457 LIST_INSERT_HEAD(&tp->t_sc, sc, sc_tpq); 3458 3459 /* Put it into the bucket. */ 3460 TAILQ_INSERT_TAIL(&scp->sch_bucket, sc, sc_bucketq); 3461 scp->sch_length++; 3462 syn_cache_count++; 3463 3464 TCP_STATINC(TCP_STAT_SC_ADDED); 3465 splx(s); 3466 } 3467 3468 /* 3469 * Walk the timer queues, looking for SYN,ACKs that need to be retransmitted. 3470 * If we have retransmitted an entry the maximum number of times, expire 3471 * that entry. 3472 */ 3473 void 3474 syn_cache_timer(void *arg) 3475 { 3476 struct syn_cache *sc = arg; 3477 3478 mutex_enter(softnet_lock); 3479 KERNEL_LOCK(1, NULL); 3480 callout_ack(&sc->sc_timer); 3481 3482 if (__predict_false(sc->sc_flags & SCF_DEAD)) { 3483 TCP_STATINC(TCP_STAT_SC_DELAYED_FREE); 3484 callout_destroy(&sc->sc_timer); 3485 pool_put(&syn_cache_pool, sc); 3486 KERNEL_UNLOCK_ONE(NULL); 3487 mutex_exit(softnet_lock); 3488 return; 3489 } 3490 3491 if (__predict_false(sc->sc_rxtshift == TCP_MAXRXTSHIFT)) { 3492 /* Drop it -- too many retransmissions. */ 3493 goto dropit; 3494 } 3495 3496 /* 3497 * Compute the total amount of time this entry has 3498 * been on a queue. If this entry has been on longer 3499 * than the keep alive timer would allow, expire it. 3500 */ 3501 sc->sc_rxttot += sc->sc_rxtcur; 3502 if (sc->sc_rxttot >= tcp_keepinit) 3503 goto dropit; 3504 3505 TCP_STATINC(TCP_STAT_SC_RETRANSMITTED); 3506 (void) syn_cache_respond(sc, NULL); 3507 3508 /* Advance the timer back-off. */ 3509 sc->sc_rxtshift++; 3510 SYN_CACHE_TIMER_ARM(sc); 3511 3512 KERNEL_UNLOCK_ONE(NULL); 3513 mutex_exit(softnet_lock); 3514 return; 3515 3516 dropit: 3517 TCP_STATINC(TCP_STAT_SC_TIMED_OUT); 3518 syn_cache_rm(sc); 3519 syn_cache_put(sc); /* calls pool_put but see spl above */ 3520 KERNEL_UNLOCK_ONE(NULL); 3521 mutex_exit(softnet_lock); 3522 } 3523 3524 /* 3525 * Remove syn cache created by the specified tcb entry, 3526 * because this does not make sense to keep them 3527 * (if there's no tcb entry, syn cache entry will never be used) 3528 */ 3529 void 3530 syn_cache_cleanup(struct tcpcb *tp) 3531 { 3532 struct syn_cache *sc, *nsc; 3533 int s; 3534 3535 s = splsoftnet(); 3536 3537 for (sc = LIST_FIRST(&tp->t_sc); sc != NULL; sc = nsc) { 3538 nsc = LIST_NEXT(sc, sc_tpq); 3539 3540 #ifdef DIAGNOSTIC 3541 if (sc->sc_tp != tp) 3542 panic("invalid sc_tp in syn_cache_cleanup"); 3543 #endif 3544 syn_cache_rm(sc); 3545 syn_cache_put(sc); /* calls pool_put but see spl above */ 3546 } 3547 /* just for safety */ 3548 LIST_INIT(&tp->t_sc); 3549 3550 splx(s); 3551 } 3552 3553 /* 3554 * Find an entry in the syn cache. 3555 */ 3556 struct syn_cache * 3557 syn_cache_lookup(const struct sockaddr *src, const struct sockaddr *dst, 3558 struct syn_cache_head **headp) 3559 { 3560 struct syn_cache *sc; 3561 struct syn_cache_head *scp; 3562 u_int32_t hash; 3563 int s; 3564 3565 SYN_HASHALL(hash, src, dst); 3566 3567 scp = &tcp_syn_cache[hash % tcp_syn_cache_size]; 3568 *headp = scp; 3569 s = splsoftnet(); 3570 for (sc = TAILQ_FIRST(&scp->sch_bucket); sc != NULL; 3571 sc = TAILQ_NEXT(sc, sc_bucketq)) { 3572 if (sc->sc_hash != hash) 3573 continue; 3574 if (!memcmp(&sc->sc_src, src, src->sa_len) && 3575 !memcmp(&sc->sc_dst, dst, dst->sa_len)) { 3576 splx(s); 3577 return (sc); 3578 } 3579 } 3580 splx(s); 3581 return (NULL); 3582 } 3583 3584 /* 3585 * This function gets called when we receive an ACK for a 3586 * socket in the LISTEN state. We look up the connection 3587 * in the syn cache, and if its there, we pull it out of 3588 * the cache and turn it into a full-blown connection in 3589 * the SYN-RECEIVED state. 3590 * 3591 * The return values may not be immediately obvious, and their effects 3592 * can be subtle, so here they are: 3593 * 3594 * NULL SYN was not found in cache; caller should drop the 3595 * packet and send an RST. 3596 * 3597 * -1 We were unable to create the new connection, and are 3598 * aborting it. An ACK,RST is being sent to the peer 3599 * (unless we got screwey sequence numbners; see below), 3600 * because the 3-way handshake has been completed. Caller 3601 * should not free the mbuf, since we may be using it. If 3602 * we are not, we will free it. 3603 * 3604 * Otherwise, the return value is a pointer to the new socket 3605 * associated with the connection. 3606 */ 3607 struct socket * 3608 syn_cache_get(struct sockaddr *src, struct sockaddr *dst, 3609 struct tcphdr *th, unsigned int hlen, unsigned int tlen, 3610 struct socket *so, struct mbuf *m) 3611 { 3612 struct syn_cache *sc; 3613 struct syn_cache_head *scp; 3614 struct inpcb *inp = NULL; 3615 #ifdef INET6 3616 struct in6pcb *in6p = NULL; 3617 #endif 3618 struct tcpcb *tp = 0; 3619 struct mbuf *am; 3620 int s; 3621 struct socket *oso; 3622 3623 s = splsoftnet(); 3624 if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { 3625 splx(s); 3626 return (NULL); 3627 } 3628 3629 /* 3630 * Verify the sequence and ack numbers. Try getting the correct 3631 * response again. 3632 */ 3633 if ((th->th_ack != sc->sc_iss + 1) || 3634 SEQ_LEQ(th->th_seq, sc->sc_irs) || 3635 SEQ_GT(th->th_seq, sc->sc_irs + 1 + sc->sc_win)) { 3636 (void) syn_cache_respond(sc, m); 3637 splx(s); 3638 return ((struct socket *)(-1)); 3639 } 3640 3641 /* Remove this cache entry */ 3642 syn_cache_rm(sc); 3643 splx(s); 3644 3645 /* 3646 * Ok, create the full blown connection, and set things up 3647 * as they would have been set up if we had created the 3648 * connection when the SYN arrived. If we can't create 3649 * the connection, abort it. 3650 */ 3651 /* 3652 * inp still has the OLD in_pcb stuff, set the 3653 * v6-related flags on the new guy, too. This is 3654 * done particularly for the case where an AF_INET6 3655 * socket is bound only to a port, and a v4 connection 3656 * comes in on that port. 3657 * we also copy the flowinfo from the original pcb 3658 * to the new one. 3659 */ 3660 oso = so; 3661 so = sonewconn(so, SS_ISCONNECTED); 3662 if (so == NULL) 3663 goto resetandabort; 3664 3665 switch (so->so_proto->pr_domain->dom_family) { 3666 #ifdef INET 3667 case AF_INET: 3668 inp = sotoinpcb(so); 3669 break; 3670 #endif 3671 #ifdef INET6 3672 case AF_INET6: 3673 in6p = sotoin6pcb(so); 3674 break; 3675 #endif 3676 } 3677 switch (src->sa_family) { 3678 #ifdef INET 3679 case AF_INET: 3680 if (inp) { 3681 inp->inp_laddr = ((struct sockaddr_in *)dst)->sin_addr; 3682 inp->inp_lport = ((struct sockaddr_in *)dst)->sin_port; 3683 inp->inp_options = ip_srcroute(); 3684 in_pcbstate(inp, INP_BOUND); 3685 if (inp->inp_options == NULL) { 3686 inp->inp_options = sc->sc_ipopts; 3687 sc->sc_ipopts = NULL; 3688 } 3689 } 3690 #ifdef INET6 3691 else if (in6p) { 3692 /* IPv4 packet to AF_INET6 socket */ 3693 memset(&in6p->in6p_laddr, 0, sizeof(in6p->in6p_laddr)); 3694 in6p->in6p_laddr.s6_addr16[5] = htons(0xffff); 3695 bcopy(&((struct sockaddr_in *)dst)->sin_addr, 3696 &in6p->in6p_laddr.s6_addr32[3], 3697 sizeof(((struct sockaddr_in *)dst)->sin_addr)); 3698 in6p->in6p_lport = ((struct sockaddr_in *)dst)->sin_port; 3699 in6totcpcb(in6p)->t_family = AF_INET; 3700 if (sotoin6pcb(oso)->in6p_flags & IN6P_IPV6_V6ONLY) 3701 in6p->in6p_flags |= IN6P_IPV6_V6ONLY; 3702 else 3703 in6p->in6p_flags &= ~IN6P_IPV6_V6ONLY; 3704 in6_pcbstate(in6p, IN6P_BOUND); 3705 } 3706 #endif 3707 break; 3708 #endif 3709 #ifdef INET6 3710 case AF_INET6: 3711 if (in6p) { 3712 in6p->in6p_laddr = ((struct sockaddr_in6 *)dst)->sin6_addr; 3713 in6p->in6p_lport = ((struct sockaddr_in6 *)dst)->sin6_port; 3714 in6_pcbstate(in6p, IN6P_BOUND); 3715 } 3716 break; 3717 #endif 3718 } 3719 #ifdef INET6 3720 if (in6p && in6totcpcb(in6p)->t_family == AF_INET6 && sotoinpcb(oso)) { 3721 struct in6pcb *oin6p = sotoin6pcb(oso); 3722 /* inherit socket options from the listening socket */ 3723 in6p->in6p_flags |= (oin6p->in6p_flags & IN6P_CONTROLOPTS); 3724 if (in6p->in6p_flags & IN6P_CONTROLOPTS) { 3725 m_freem(in6p->in6p_options); 3726 in6p->in6p_options = 0; 3727 } 3728 ip6_savecontrol(in6p, &in6p->in6p_options, 3729 mtod(m, struct ip6_hdr *), m); 3730 } 3731 #endif 3732 3733 #if defined(IPSEC) || defined(FAST_IPSEC) 3734 /* 3735 * we make a copy of policy, instead of sharing the policy, 3736 * for better behavior in terms of SA lookup and dead SA removal. 3737 */ 3738 if (inp) { 3739 /* copy old policy into new socket's */ 3740 if (ipsec_copy_pcbpolicy(sotoinpcb(oso)->inp_sp, inp->inp_sp)) 3741 printf("tcp_input: could not copy policy\n"); 3742 } 3743 #ifdef INET6 3744 else if (in6p) { 3745 /* copy old policy into new socket's */ 3746 if (ipsec_copy_pcbpolicy(sotoin6pcb(oso)->in6p_sp, 3747 in6p->in6p_sp)) 3748 printf("tcp_input: could not copy policy\n"); 3749 } 3750 #endif 3751 #endif 3752 3753 /* 3754 * Give the new socket our cached route reference. 3755 */ 3756 if (inp) { 3757 rtcache_copy(&inp->inp_route, &sc->sc_route); 3758 rtcache_free(&sc->sc_route); 3759 } 3760 #ifdef INET6 3761 else { 3762 rtcache_copy(&in6p->in6p_route, &sc->sc_route); 3763 rtcache_free(&sc->sc_route); 3764 } 3765 #endif 3766 3767 am = m_get(M_DONTWAIT, MT_SONAME); /* XXX */ 3768 if (am == NULL) 3769 goto resetandabort; 3770 MCLAIM(am, &tcp_mowner); 3771 am->m_len = src->sa_len; 3772 bcopy(src, mtod(am, void *), src->sa_len); 3773 if (inp) { 3774 if (in_pcbconnect(inp, am, &lwp0)) { 3775 (void) m_free(am); 3776 goto resetandabort; 3777 } 3778 } 3779 #ifdef INET6 3780 else if (in6p) { 3781 if (src->sa_family == AF_INET) { 3782 /* IPv4 packet to AF_INET6 socket */ 3783 struct sockaddr_in6 *sin6; 3784 sin6 = mtod(am, struct sockaddr_in6 *); 3785 am->m_len = sizeof(*sin6); 3786 memset(sin6, 0, sizeof(*sin6)); 3787 sin6->sin6_family = AF_INET6; 3788 sin6->sin6_len = sizeof(*sin6); 3789 sin6->sin6_port = ((struct sockaddr_in *)src)->sin_port; 3790 sin6->sin6_addr.s6_addr16[5] = htons(0xffff); 3791 bcopy(&((struct sockaddr_in *)src)->sin_addr, 3792 &sin6->sin6_addr.s6_addr32[3], 3793 sizeof(sin6->sin6_addr.s6_addr32[3])); 3794 } 3795 if (in6_pcbconnect(in6p, am, NULL)) { 3796 (void) m_free(am); 3797 goto resetandabort; 3798 } 3799 } 3800 #endif 3801 else { 3802 (void) m_free(am); 3803 goto resetandabort; 3804 } 3805 (void) m_free(am); 3806 3807 if (inp) 3808 tp = intotcpcb(inp); 3809 #ifdef INET6 3810 else if (in6p) 3811 tp = in6totcpcb(in6p); 3812 #endif 3813 else 3814 tp = NULL; 3815 tp->t_flags = sototcpcb(oso)->t_flags & TF_NODELAY; 3816 if (sc->sc_request_r_scale != 15) { 3817 tp->requested_s_scale = sc->sc_requested_s_scale; 3818 tp->request_r_scale = sc->sc_request_r_scale; 3819 tp->snd_scale = sc->sc_requested_s_scale; 3820 tp->rcv_scale = sc->sc_request_r_scale; 3821 tp->t_flags |= TF_REQ_SCALE|TF_RCVD_SCALE; 3822 } 3823 if (sc->sc_flags & SCF_TIMESTAMP) 3824 tp->t_flags |= TF_REQ_TSTMP|TF_RCVD_TSTMP; 3825 tp->ts_timebase = sc->sc_timebase; 3826 3827 tp->t_template = tcp_template(tp); 3828 if (tp->t_template == 0) { 3829 tp = tcp_drop(tp, ENOBUFS); /* destroys socket */ 3830 so = NULL; 3831 m_freem(m); 3832 goto abort; 3833 } 3834 3835 tp->iss = sc->sc_iss; 3836 tp->irs = sc->sc_irs; 3837 tcp_sendseqinit(tp); 3838 tcp_rcvseqinit(tp); 3839 tp->t_state = TCPS_SYN_RECEIVED; 3840 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepinit); 3841 TCP_STATINC(TCP_STAT_ACCEPTS); 3842 3843 if ((sc->sc_flags & SCF_SACK_PERMIT) && tcp_do_sack) 3844 tp->t_flags |= TF_WILL_SACK; 3845 3846 if ((sc->sc_flags & SCF_ECN_PERMIT) && tcp_do_ecn) 3847 tp->t_flags |= TF_ECN_PERMIT; 3848 3849 #ifdef TCP_SIGNATURE 3850 if (sc->sc_flags & SCF_SIGNATURE) 3851 tp->t_flags |= TF_SIGNATURE; 3852 #endif 3853 3854 /* Initialize tp->t_ourmss before we deal with the peer's! */ 3855 tp->t_ourmss = sc->sc_ourmaxseg; 3856 tcp_mss_from_peer(tp, sc->sc_peermaxseg); 3857 3858 /* 3859 * Initialize the initial congestion window. If we 3860 * had to retransmit the SYN,ACK, we must initialize cwnd 3861 * to 1 segment (i.e. the Loss Window). 3862 */ 3863 if (sc->sc_rxtshift) 3864 tp->snd_cwnd = tp->t_peermss; 3865 else { 3866 int ss = tcp_init_win; 3867 #ifdef INET 3868 if (inp != NULL && in_localaddr(inp->inp_faddr)) 3869 ss = tcp_init_win_local; 3870 #endif 3871 #ifdef INET6 3872 if (in6p != NULL && in6_localaddr(&in6p->in6p_faddr)) 3873 ss = tcp_init_win_local; 3874 #endif 3875 tp->snd_cwnd = TCP_INITIAL_WINDOW(ss, tp->t_peermss); 3876 } 3877 3878 tcp_rmx_rtt(tp); 3879 tp->snd_wl1 = sc->sc_irs; 3880 tp->rcv_up = sc->sc_irs + 1; 3881 3882 /* 3883 * This is what whould have happened in tcp_output() when 3884 * the SYN,ACK was sent. 3885 */ 3886 tp->snd_up = tp->snd_una; 3887 tp->snd_max = tp->snd_nxt = tp->iss+1; 3888 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 3889 if (sc->sc_win > 0 && SEQ_GT(tp->rcv_nxt + sc->sc_win, tp->rcv_adv)) 3890 tp->rcv_adv = tp->rcv_nxt + sc->sc_win; 3891 tp->last_ack_sent = tp->rcv_nxt; 3892 tp->t_partialacks = -1; 3893 tp->t_dupacks = 0; 3894 3895 TCP_STATINC(TCP_STAT_SC_COMPLETED); 3896 s = splsoftnet(); 3897 syn_cache_put(sc); 3898 splx(s); 3899 return (so); 3900 3901 resetandabort: 3902 (void)tcp_respond(NULL, m, m, th, (tcp_seq)0, th->th_ack, TH_RST); 3903 abort: 3904 if (so != NULL) { 3905 (void) soqremque(so, 1); 3906 (void) soabort(so); 3907 mutex_enter(softnet_lock); 3908 } 3909 s = splsoftnet(); 3910 syn_cache_put(sc); 3911 splx(s); 3912 TCP_STATINC(TCP_STAT_SC_ABORTED); 3913 return ((struct socket *)(-1)); 3914 } 3915 3916 /* 3917 * This function is called when we get a RST for a 3918 * non-existent connection, so that we can see if the 3919 * connection is in the syn cache. If it is, zap it. 3920 */ 3921 3922 void 3923 syn_cache_reset(struct sockaddr *src, struct sockaddr *dst, struct tcphdr *th) 3924 { 3925 struct syn_cache *sc; 3926 struct syn_cache_head *scp; 3927 int s = splsoftnet(); 3928 3929 if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { 3930 splx(s); 3931 return; 3932 } 3933 if (SEQ_LT(th->th_seq, sc->sc_irs) || 3934 SEQ_GT(th->th_seq, sc->sc_irs+1)) { 3935 splx(s); 3936 return; 3937 } 3938 syn_cache_rm(sc); 3939 TCP_STATINC(TCP_STAT_SC_RESET); 3940 syn_cache_put(sc); /* calls pool_put but see spl above */ 3941 splx(s); 3942 } 3943 3944 void 3945 syn_cache_unreach(const struct sockaddr *src, const struct sockaddr *dst, 3946 struct tcphdr *th) 3947 { 3948 struct syn_cache *sc; 3949 struct syn_cache_head *scp; 3950 int s; 3951 3952 s = splsoftnet(); 3953 if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { 3954 splx(s); 3955 return; 3956 } 3957 /* If the sequence number != sc_iss, then it's a bogus ICMP msg */ 3958 if (ntohl (th->th_seq) != sc->sc_iss) { 3959 splx(s); 3960 return; 3961 } 3962 3963 /* 3964 * If we've retransmitted 3 times and this is our second error, 3965 * we remove the entry. Otherwise, we allow it to continue on. 3966 * This prevents us from incorrectly nuking an entry during a 3967 * spurious network outage. 3968 * 3969 * See tcp_notify(). 3970 */ 3971 if ((sc->sc_flags & SCF_UNREACH) == 0 || sc->sc_rxtshift < 3) { 3972 sc->sc_flags |= SCF_UNREACH; 3973 splx(s); 3974 return; 3975 } 3976 3977 syn_cache_rm(sc); 3978 TCP_STATINC(TCP_STAT_SC_UNREACH); 3979 syn_cache_put(sc); /* calls pool_put but see spl above */ 3980 splx(s); 3981 } 3982 3983 /* 3984 * Given a LISTEN socket and an inbound SYN request, add 3985 * this to the syn cache, and send back a segment: 3986 * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK> 3987 * to the source. 3988 * 3989 * IMPORTANT NOTE: We do _NOT_ ACK data that might accompany the SYN. 3990 * Doing so would require that we hold onto the data and deliver it 3991 * to the application. However, if we are the target of a SYN-flood 3992 * DoS attack, an attacker could send data which would eventually 3993 * consume all available buffer space if it were ACKed. By not ACKing 3994 * the data, we avoid this DoS scenario. 3995 */ 3996 3997 int 3998 syn_cache_add(struct sockaddr *src, struct sockaddr *dst, struct tcphdr *th, 3999 unsigned int hlen, struct socket *so, struct mbuf *m, u_char *optp, 4000 int optlen, struct tcp_opt_info *oi) 4001 { 4002 struct tcpcb tb, *tp; 4003 long win; 4004 struct syn_cache *sc; 4005 struct syn_cache_head *scp; 4006 struct mbuf *ipopts; 4007 struct tcp_opt_info opti; 4008 int s; 4009 4010 tp = sototcpcb(so); 4011 4012 memset(&opti, 0, sizeof(opti)); 4013 4014 /* 4015 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN 4016 * 4017 * Note this check is performed in tcp_input() very early on. 4018 */ 4019 4020 /* 4021 * Initialize some local state. 4022 */ 4023 win = sbspace(&so->so_rcv); 4024 if (win > TCP_MAXWIN) 4025 win = TCP_MAXWIN; 4026 4027 switch (src->sa_family) { 4028 #ifdef INET 4029 case AF_INET: 4030 /* 4031 * Remember the IP options, if any. 4032 */ 4033 ipopts = ip_srcroute(); 4034 break; 4035 #endif 4036 default: 4037 ipopts = NULL; 4038 } 4039 4040 #ifdef TCP_SIGNATURE 4041 if (optp || (tp->t_flags & TF_SIGNATURE)) 4042 #else 4043 if (optp) 4044 #endif 4045 { 4046 tb.t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; 4047 #ifdef TCP_SIGNATURE 4048 tb.t_flags |= (tp->t_flags & TF_SIGNATURE); 4049 #endif 4050 tb.t_state = TCPS_LISTEN; 4051 if (tcp_dooptions(&tb, optp, optlen, th, m, m->m_pkthdr.len - 4052 sizeof(struct tcphdr) - optlen - hlen, oi) < 0) 4053 return (0); 4054 } else 4055 tb.t_flags = 0; 4056 4057 /* 4058 * See if we already have an entry for this connection. 4059 * If we do, resend the SYN,ACK. We do not count this 4060 * as a retransmission (XXX though maybe we should). 4061 */ 4062 if ((sc = syn_cache_lookup(src, dst, &scp)) != NULL) { 4063 TCP_STATINC(TCP_STAT_SC_DUPESYN); 4064 if (ipopts) { 4065 /* 4066 * If we were remembering a previous source route, 4067 * forget it and use the new one we've been given. 4068 */ 4069 if (sc->sc_ipopts) 4070 (void) m_free(sc->sc_ipopts); 4071 sc->sc_ipopts = ipopts; 4072 } 4073 sc->sc_timestamp = tb.ts_recent; 4074 if (syn_cache_respond(sc, m) == 0) { 4075 uint64_t *tcps = TCP_STAT_GETREF(); 4076 tcps[TCP_STAT_SNDACKS]++; 4077 tcps[TCP_STAT_SNDTOTAL]++; 4078 TCP_STAT_PUTREF(); 4079 } 4080 return (1); 4081 } 4082 4083 s = splsoftnet(); 4084 sc = pool_get(&syn_cache_pool, PR_NOWAIT); 4085 splx(s); 4086 if (sc == NULL) { 4087 if (ipopts) 4088 (void) m_free(ipopts); 4089 return (0); 4090 } 4091 4092 /* 4093 * Fill in the cache, and put the necessary IP and TCP 4094 * options into the reply. 4095 */ 4096 memset(sc, 0, sizeof(struct syn_cache)); 4097 callout_init(&sc->sc_timer, CALLOUT_MPSAFE); 4098 bcopy(src, &sc->sc_src, src->sa_len); 4099 bcopy(dst, &sc->sc_dst, dst->sa_len); 4100 sc->sc_flags = 0; 4101 sc->sc_ipopts = ipopts; 4102 sc->sc_irs = th->th_seq; 4103 switch (src->sa_family) { 4104 #ifdef INET 4105 case AF_INET: 4106 { 4107 struct sockaddr_in *srcin = (void *) src; 4108 struct sockaddr_in *dstin = (void *) dst; 4109 4110 sc->sc_iss = tcp_new_iss1(&dstin->sin_addr, 4111 &srcin->sin_addr, dstin->sin_port, 4112 srcin->sin_port, sizeof(dstin->sin_addr), 0); 4113 break; 4114 } 4115 #endif /* INET */ 4116 #ifdef INET6 4117 case AF_INET6: 4118 { 4119 struct sockaddr_in6 *srcin6 = (void *) src; 4120 struct sockaddr_in6 *dstin6 = (void *) dst; 4121 4122 sc->sc_iss = tcp_new_iss1(&dstin6->sin6_addr, 4123 &srcin6->sin6_addr, dstin6->sin6_port, 4124 srcin6->sin6_port, sizeof(dstin6->sin6_addr), 0); 4125 break; 4126 } 4127 #endif /* INET6 */ 4128 } 4129 sc->sc_peermaxseg = oi->maxseg; 4130 sc->sc_ourmaxseg = tcp_mss_to_advertise(m->m_flags & M_PKTHDR ? 4131 m->m_pkthdr.rcvif : NULL, 4132 sc->sc_src.sa.sa_family); 4133 sc->sc_win = win; 4134 sc->sc_timebase = tcp_now - 1; /* see tcp_newtcpcb() */ 4135 sc->sc_timestamp = tb.ts_recent; 4136 if ((tb.t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP)) == 4137 (TF_REQ_TSTMP|TF_RCVD_TSTMP)) 4138 sc->sc_flags |= SCF_TIMESTAMP; 4139 if ((tb.t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == 4140 (TF_RCVD_SCALE|TF_REQ_SCALE)) { 4141 sc->sc_requested_s_scale = tb.requested_s_scale; 4142 sc->sc_request_r_scale = 0; 4143 /* 4144 * Pick the smallest possible scaling factor that 4145 * will still allow us to scale up to sb_max. 4146 * 4147 * We do this because there are broken firewalls that 4148 * will corrupt the window scale option, leading to 4149 * the other endpoint believing that our advertised 4150 * window is unscaled. At scale factors larger than 4151 * 5 the unscaled window will drop below 1500 bytes, 4152 * leading to serious problems when traversing these 4153 * broken firewalls. 4154 * 4155 * With the default sbmax of 256K, a scale factor 4156 * of 3 will be chosen by this algorithm. Those who 4157 * choose a larger sbmax should watch out 4158 * for the compatiblity problems mentioned above. 4159 * 4160 * RFC1323: The Window field in a SYN (i.e., a <SYN> 4161 * or <SYN,ACK>) segment itself is never scaled. 4162 */ 4163 while (sc->sc_request_r_scale < TCP_MAX_WINSHIFT && 4164 (TCP_MAXWIN << sc->sc_request_r_scale) < sb_max) 4165 sc->sc_request_r_scale++; 4166 } else { 4167 sc->sc_requested_s_scale = 15; 4168 sc->sc_request_r_scale = 15; 4169 } 4170 if ((tb.t_flags & TF_SACK_PERMIT) && tcp_do_sack) 4171 sc->sc_flags |= SCF_SACK_PERMIT; 4172 4173 /* 4174 * ECN setup packet recieved. 4175 */ 4176 if ((th->th_flags & (TH_ECE|TH_CWR)) && tcp_do_ecn) 4177 sc->sc_flags |= SCF_ECN_PERMIT; 4178 4179 #ifdef TCP_SIGNATURE 4180 if (tb.t_flags & TF_SIGNATURE) 4181 sc->sc_flags |= SCF_SIGNATURE; 4182 #endif 4183 sc->sc_tp = tp; 4184 if (syn_cache_respond(sc, m) == 0) { 4185 uint64_t *tcps = TCP_STAT_GETREF(); 4186 tcps[TCP_STAT_SNDACKS]++; 4187 tcps[TCP_STAT_SNDTOTAL]++; 4188 TCP_STAT_PUTREF(); 4189 syn_cache_insert(sc, tp); 4190 } else { 4191 s = splsoftnet(); 4192 syn_cache_put(sc); 4193 splx(s); 4194 TCP_STATINC(TCP_STAT_SC_DROPPED); 4195 } 4196 return (1); 4197 } 4198 4199 int 4200 syn_cache_respond(struct syn_cache *sc, struct mbuf *m) 4201 { 4202 #ifdef INET6 4203 struct rtentry *rt; 4204 #endif 4205 struct route *ro; 4206 u_int8_t *optp; 4207 int optlen, error; 4208 u_int16_t tlen; 4209 struct ip *ip = NULL; 4210 #ifdef INET6 4211 struct ip6_hdr *ip6 = NULL; 4212 #endif 4213 struct tcpcb *tp = NULL; 4214 struct tcphdr *th; 4215 u_int hlen; 4216 struct socket *so; 4217 4218 ro = &sc->sc_route; 4219 switch (sc->sc_src.sa.sa_family) { 4220 case AF_INET: 4221 hlen = sizeof(struct ip); 4222 break; 4223 #ifdef INET6 4224 case AF_INET6: 4225 hlen = sizeof(struct ip6_hdr); 4226 break; 4227 #endif 4228 default: 4229 if (m) 4230 m_freem(m); 4231 return (EAFNOSUPPORT); 4232 } 4233 4234 /* Compute the size of the TCP options. */ 4235 optlen = 4 + (sc->sc_request_r_scale != 15 ? 4 : 0) + 4236 ((sc->sc_flags & SCF_SACK_PERMIT) ? (TCPOLEN_SACK_PERMITTED + 2) : 0) + 4237 #ifdef TCP_SIGNATURE 4238 ((sc->sc_flags & SCF_SIGNATURE) ? (TCPOLEN_SIGNATURE + 2) : 0) + 4239 #endif 4240 ((sc->sc_flags & SCF_TIMESTAMP) ? TCPOLEN_TSTAMP_APPA : 0); 4241 4242 tlen = hlen + sizeof(struct tcphdr) + optlen; 4243 4244 /* 4245 * Create the IP+TCP header from scratch. 4246 */ 4247 if (m) 4248 m_freem(m); 4249 #ifdef DIAGNOSTIC 4250 if (max_linkhdr + tlen > MCLBYTES) 4251 return (ENOBUFS); 4252 #endif 4253 MGETHDR(m, M_DONTWAIT, MT_DATA); 4254 if (m && tlen > MHLEN) { 4255 MCLGET(m, M_DONTWAIT); 4256 if ((m->m_flags & M_EXT) == 0) { 4257 m_freem(m); 4258 m = NULL; 4259 } 4260 } 4261 if (m == NULL) 4262 return (ENOBUFS); 4263 MCLAIM(m, &tcp_tx_mowner); 4264 4265 /* Fixup the mbuf. */ 4266 m->m_data += max_linkhdr; 4267 m->m_len = m->m_pkthdr.len = tlen; 4268 if (sc->sc_tp) { 4269 tp = sc->sc_tp; 4270 if (tp->t_inpcb) 4271 so = tp->t_inpcb->inp_socket; 4272 #ifdef INET6 4273 else if (tp->t_in6pcb) 4274 so = tp->t_in6pcb->in6p_socket; 4275 #endif 4276 else 4277 so = NULL; 4278 } else 4279 so = NULL; 4280 m->m_pkthdr.rcvif = NULL; 4281 memset(mtod(m, u_char *), 0, tlen); 4282 4283 switch (sc->sc_src.sa.sa_family) { 4284 case AF_INET: 4285 ip = mtod(m, struct ip *); 4286 ip->ip_v = 4; 4287 ip->ip_dst = sc->sc_src.sin.sin_addr; 4288 ip->ip_src = sc->sc_dst.sin.sin_addr; 4289 ip->ip_p = IPPROTO_TCP; 4290 th = (struct tcphdr *)(ip + 1); 4291 th->th_dport = sc->sc_src.sin.sin_port; 4292 th->th_sport = sc->sc_dst.sin.sin_port; 4293 break; 4294 #ifdef INET6 4295 case AF_INET6: 4296 ip6 = mtod(m, struct ip6_hdr *); 4297 ip6->ip6_vfc = IPV6_VERSION; 4298 ip6->ip6_dst = sc->sc_src.sin6.sin6_addr; 4299 ip6->ip6_src = sc->sc_dst.sin6.sin6_addr; 4300 ip6->ip6_nxt = IPPROTO_TCP; 4301 /* ip6_plen will be updated in ip6_output() */ 4302 th = (struct tcphdr *)(ip6 + 1); 4303 th->th_dport = sc->sc_src.sin6.sin6_port; 4304 th->th_sport = sc->sc_dst.sin6.sin6_port; 4305 break; 4306 #endif 4307 default: 4308 th = NULL; 4309 } 4310 4311 th->th_seq = htonl(sc->sc_iss); 4312 th->th_ack = htonl(sc->sc_irs + 1); 4313 th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; 4314 th->th_flags = TH_SYN|TH_ACK; 4315 th->th_win = htons(sc->sc_win); 4316 /* th_sum already 0 */ 4317 /* th_urp already 0 */ 4318 4319 /* Tack on the TCP options. */ 4320 optp = (u_int8_t *)(th + 1); 4321 *optp++ = TCPOPT_MAXSEG; 4322 *optp++ = 4; 4323 *optp++ = (sc->sc_ourmaxseg >> 8) & 0xff; 4324 *optp++ = sc->sc_ourmaxseg & 0xff; 4325 4326 if (sc->sc_request_r_scale != 15) { 4327 *((u_int32_t *)optp) = htonl(TCPOPT_NOP << 24 | 4328 TCPOPT_WINDOW << 16 | TCPOLEN_WINDOW << 8 | 4329 sc->sc_request_r_scale); 4330 optp += 4; 4331 } 4332 4333 if (sc->sc_flags & SCF_TIMESTAMP) { 4334 u_int32_t *lp = (u_int32_t *)(optp); 4335 /* Form timestamp option as shown in appendix A of RFC 1323. */ 4336 *lp++ = htonl(TCPOPT_TSTAMP_HDR); 4337 *lp++ = htonl(SYN_CACHE_TIMESTAMP(sc)); 4338 *lp = htonl(sc->sc_timestamp); 4339 optp += TCPOLEN_TSTAMP_APPA; 4340 } 4341 4342 if (sc->sc_flags & SCF_SACK_PERMIT) { 4343 u_int8_t *p = optp; 4344 4345 /* Let the peer know that we will SACK. */ 4346 p[0] = TCPOPT_SACK_PERMITTED; 4347 p[1] = 2; 4348 p[2] = TCPOPT_NOP; 4349 p[3] = TCPOPT_NOP; 4350 optp += 4; 4351 } 4352 4353 /* 4354 * Send ECN SYN-ACK setup packet. 4355 * Routes can be asymetric, so, even if we receive a packet 4356 * with ECE and CWR set, we must not assume no one will block 4357 * the ECE packet we are about to send. 4358 */ 4359 if ((sc->sc_flags & SCF_ECN_PERMIT) && tp && 4360 SEQ_GEQ(tp->snd_nxt, tp->snd_max)) { 4361 th->th_flags |= TH_ECE; 4362 TCP_STATINC(TCP_STAT_ECN_SHS); 4363 4364 /* 4365 * draft-ietf-tcpm-ecnsyn-00.txt 4366 * 4367 * "[...] a TCP node MAY respond to an ECN-setup 4368 * SYN packet by setting ECT in the responding 4369 * ECN-setup SYN/ACK packet, indicating to routers 4370 * that the SYN/ACK packet is ECN-Capable. 4371 * This allows a congested router along the path 4372 * to mark the packet instead of dropping the 4373 * packet as an indication of congestion." 4374 * 4375 * "[...] There can be a great benefit in setting 4376 * an ECN-capable codepoint in SYN/ACK packets [...] 4377 * Congestion is most likely to occur in 4378 * the server-to-client direction. As a result, 4379 * setting an ECN-capable codepoint in SYN/ACK 4380 * packets can reduce the occurence of three-second 4381 * retransmit timeouts resulting from the drop 4382 * of SYN/ACK packets." 4383 * 4384 * Page 4 and 6, January 2006. 4385 */ 4386 4387 switch (sc->sc_src.sa.sa_family) { 4388 #ifdef INET 4389 case AF_INET: 4390 ip->ip_tos |= IPTOS_ECN_ECT0; 4391 break; 4392 #endif 4393 #ifdef INET6 4394 case AF_INET6: 4395 ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20); 4396 break; 4397 #endif 4398 } 4399 TCP_STATINC(TCP_STAT_ECN_ECT); 4400 } 4401 4402 #ifdef TCP_SIGNATURE 4403 if (sc->sc_flags & SCF_SIGNATURE) { 4404 struct secasvar *sav; 4405 u_int8_t *sigp; 4406 4407 sav = tcp_signature_getsav(m, th); 4408 4409 if (sav == NULL) { 4410 if (m) 4411 m_freem(m); 4412 return (EPERM); 4413 } 4414 4415 *optp++ = TCPOPT_SIGNATURE; 4416 *optp++ = TCPOLEN_SIGNATURE; 4417 sigp = optp; 4418 memset(optp, 0, TCP_SIGLEN); 4419 optp += TCP_SIGLEN; 4420 *optp++ = TCPOPT_NOP; 4421 *optp++ = TCPOPT_EOL; 4422 4423 (void)tcp_signature(m, th, hlen, sav, sigp); 4424 4425 key_sa_recordxfer(sav, m); 4426 #ifdef FAST_IPSEC 4427 KEY_FREESAV(&sav); 4428 #else 4429 key_freesav(sav); 4430 #endif 4431 } 4432 #endif 4433 4434 /* Compute the packet's checksum. */ 4435 switch (sc->sc_src.sa.sa_family) { 4436 case AF_INET: 4437 ip->ip_len = htons(tlen - hlen); 4438 th->th_sum = 0; 4439 th->th_sum = in4_cksum(m, IPPROTO_TCP, hlen, tlen - hlen); 4440 break; 4441 #ifdef INET6 4442 case AF_INET6: 4443 ip6->ip6_plen = htons(tlen - hlen); 4444 th->th_sum = 0; 4445 th->th_sum = in6_cksum(m, IPPROTO_TCP, hlen, tlen - hlen); 4446 break; 4447 #endif 4448 } 4449 4450 /* 4451 * Fill in some straggling IP bits. Note the stack expects 4452 * ip_len to be in host order, for convenience. 4453 */ 4454 switch (sc->sc_src.sa.sa_family) { 4455 #ifdef INET 4456 case AF_INET: 4457 ip->ip_len = htons(tlen); 4458 ip->ip_ttl = ip_defttl; 4459 /* XXX tos? */ 4460 break; 4461 #endif 4462 #ifdef INET6 4463 case AF_INET6: 4464 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 4465 ip6->ip6_vfc |= IPV6_VERSION; 4466 ip6->ip6_plen = htons(tlen - hlen); 4467 /* ip6_hlim will be initialized afterwards */ 4468 /* XXX flowlabel? */ 4469 break; 4470 #endif 4471 } 4472 4473 /* XXX use IPsec policy on listening socket, on SYN ACK */ 4474 tp = sc->sc_tp; 4475 4476 switch (sc->sc_src.sa.sa_family) { 4477 #ifdef INET 4478 case AF_INET: 4479 error = ip_output(m, sc->sc_ipopts, ro, 4480 (ip_mtudisc ? IP_MTUDISC : 0), 4481 (struct ip_moptions *)NULL, so); 4482 break; 4483 #endif 4484 #ifdef INET6 4485 case AF_INET6: 4486 ip6->ip6_hlim = in6_selecthlim(NULL, 4487 (rt = rtcache_validate(ro)) != NULL ? rt->rt_ifp 4488 : NULL); 4489 4490 error = ip6_output(m, NULL /*XXX*/, ro, 0, NULL, so, NULL); 4491 break; 4492 #endif 4493 default: 4494 error = EAFNOSUPPORT; 4495 break; 4496 } 4497 return (error); 4498 } 4499