1 /* $NetBSD: tcp_input.c,v 1.282 2008/03/01 14:16:52 rmind 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 * 3. All advertising materials mentioning features or use of this software 93 * must display the following acknowledgement: 94 * This product includes software developed by the NetBSD 95 * Foundation, Inc. and its contributors. 96 * 4. Neither the name of The NetBSD Foundation nor the names of its 97 * contributors may be used to endorse or promote products derived 98 * from this software without specific prior written permission. 99 * 100 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 101 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 102 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 103 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 104 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 105 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 106 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 107 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 108 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 109 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 110 * POSSIBILITY OF SUCH DAMAGE. 111 */ 112 113 /* 114 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995 115 * The Regents of the University of California. All rights reserved. 116 * 117 * Redistribution and use in source and binary forms, with or without 118 * modification, are permitted provided that the following conditions 119 * are met: 120 * 1. Redistributions of source code must retain the above copyright 121 * notice, this list of conditions and the following disclaimer. 122 * 2. Redistributions in binary form must reproduce the above copyright 123 * notice, this list of conditions and the following disclaimer in the 124 * documentation and/or other materials provided with the distribution. 125 * 3. Neither the name of the University nor the names of its contributors 126 * may be used to endorse or promote products derived from this software 127 * without specific prior written permission. 128 * 129 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 130 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 131 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 132 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 133 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 134 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 135 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 136 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 137 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 138 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 139 * SUCH DAMAGE. 140 * 141 * @(#)tcp_input.c 8.12 (Berkeley) 5/24/95 142 */ 143 144 /* 145 * TODO list for SYN cache stuff: 146 * 147 * Find room for a "state" field, which is needed to keep a 148 * compressed state for TIME_WAIT TCBs. It's been noted already 149 * that this is fairly important for very high-volume web and 150 * mail servers, which use a large number of short-lived 151 * connections. 152 */ 153 154 #include <sys/cdefs.h> 155 __KERNEL_RCSID(0, "$NetBSD: tcp_input.c,v 1.282 2008/03/01 14:16:52 rmind Exp $"); 156 157 #include "opt_inet.h" 158 #include "opt_ipsec.h" 159 #include "opt_inet_csum.h" 160 #include "opt_tcp_debug.h" 161 162 #include <sys/param.h> 163 #include <sys/systm.h> 164 #include <sys/malloc.h> 165 #include <sys/mbuf.h> 166 #include <sys/protosw.h> 167 #include <sys/socket.h> 168 #include <sys/socketvar.h> 169 #include <sys/errno.h> 170 #include <sys/syslog.h> 171 #include <sys/pool.h> 172 #include <sys/domain.h> 173 #include <sys/kernel.h> 174 #ifdef TCP_SIGNATURE 175 #include <sys/md5.h> 176 #endif 177 #include <sys/lwp.h> /* for lwp0 */ 178 179 #include <net/if.h> 180 #include <net/route.h> 181 #include <net/if_types.h> 182 183 #include <netinet/in.h> 184 #include <netinet/in_systm.h> 185 #include <netinet/ip.h> 186 #include <netinet/in_pcb.h> 187 #include <netinet/in_var.h> 188 #include <netinet/ip_var.h> 189 #include <netinet/in_offload.h> 190 191 #ifdef INET6 192 #ifndef INET 193 #include <netinet/in.h> 194 #endif 195 #include <netinet/ip6.h> 196 #include <netinet6/ip6_var.h> 197 #include <netinet6/in6_pcb.h> 198 #include <netinet6/ip6_var.h> 199 #include <netinet6/in6_var.h> 200 #include <netinet/icmp6.h> 201 #include <netinet6/nd6.h> 202 #ifdef TCP_SIGNATURE 203 #include <netinet6/scope6_var.h> 204 #endif 205 #endif 206 207 #ifndef INET6 208 /* always need ip6.h for IP6_EXTHDR_GET */ 209 #include <netinet/ip6.h> 210 #endif 211 212 #include <netinet/tcp.h> 213 #include <netinet/tcp_fsm.h> 214 #include <netinet/tcp_seq.h> 215 #include <netinet/tcp_timer.h> 216 #include <netinet/tcp_var.h> 217 #include <netinet/tcpip.h> 218 #include <netinet/tcp_congctl.h> 219 #include <netinet/tcp_debug.h> 220 221 #include <machine/stdarg.h> 222 223 #ifdef IPSEC 224 #include <netinet6/ipsec.h> 225 #include <netkey/key.h> 226 #endif /*IPSEC*/ 227 #ifdef INET6 228 #include "faith.h" 229 #if defined(NFAITH) && NFAITH > 0 230 #include <net/if_faith.h> 231 #endif 232 #endif /* IPSEC */ 233 234 #ifdef FAST_IPSEC 235 #include <netipsec/ipsec.h> 236 #include <netipsec/ipsec_var.h> /* XXX ipsecstat namespace */ 237 #include <netipsec/key.h> 238 #ifdef INET6 239 #include <netipsec/ipsec6.h> 240 #endif 241 #endif /* FAST_IPSEC*/ 242 243 int tcprexmtthresh = 3; 244 int tcp_log_refused; 245 246 int tcp_do_autorcvbuf = 0; 247 int tcp_autorcvbuf_inc = 16 * 1024; 248 int tcp_autorcvbuf_max = 256 * 1024; 249 250 static int tcp_rst_ppslim_count = 0; 251 static struct timeval tcp_rst_ppslim_last; 252 static int tcp_ackdrop_ppslim_count = 0; 253 static struct timeval tcp_ackdrop_ppslim_last; 254 255 #define TCP_PAWS_IDLE (24U * 24 * 60 * 60 * PR_SLOWHZ) 256 257 /* for modulo comparisons of timestamps */ 258 #define TSTMP_LT(a,b) ((int)((a)-(b)) < 0) 259 #define TSTMP_GEQ(a,b) ((int)((a)-(b)) >= 0) 260 261 /* 262 * Neighbor Discovery, Neighbor Unreachability Detection Upper layer hint. 263 */ 264 #ifdef INET6 265 static inline void 266 nd6_hint(struct tcpcb *tp) 267 { 268 struct rtentry *rt; 269 270 if (tp != NULL && tp->t_in6pcb != NULL && tp->t_family == AF_INET6 && 271 (rt = rtcache_validate(&tp->t_in6pcb->in6p_route)) != NULL) 272 nd6_nud_hint(rt, NULL, 0); 273 } 274 #else 275 static inline void 276 nd6_hint(struct tcpcb *tp) 277 { 278 } 279 #endif 280 281 /* 282 * Compute ACK transmission behavior. Delay the ACK unless 283 * we have already delayed an ACK (must send an ACK every two segments). 284 * We also ACK immediately if we received a PUSH and the ACK-on-PUSH 285 * option is enabled. 286 */ 287 static void 288 tcp_setup_ack(struct tcpcb *tp, const struct tcphdr *th) 289 { 290 291 if (tp->t_flags & TF_DELACK || 292 (tcp_ack_on_push && th->th_flags & TH_PUSH)) 293 tp->t_flags |= TF_ACKNOW; 294 else 295 TCP_SET_DELACK(tp); 296 } 297 298 static void 299 icmp_check(struct tcpcb *tp, const struct tcphdr *th, int acked) 300 { 301 302 /* 303 * If we had a pending ICMP message that refers to data that have 304 * just been acknowledged, disregard the recorded ICMP message. 305 */ 306 if ((tp->t_flags & TF_PMTUD_PEND) && 307 SEQ_GT(th->th_ack, tp->t_pmtud_th_seq)) 308 tp->t_flags &= ~TF_PMTUD_PEND; 309 310 /* 311 * Keep track of the largest chunk of data 312 * acknowledged since last PMTU update 313 */ 314 if (tp->t_pmtud_mss_acked < acked) 315 tp->t_pmtud_mss_acked = acked; 316 } 317 318 /* 319 * Convert TCP protocol fields to host order for easier processing. 320 */ 321 static void 322 tcp_fields_to_host(struct tcphdr *th) 323 { 324 325 NTOHL(th->th_seq); 326 NTOHL(th->th_ack); 327 NTOHS(th->th_win); 328 NTOHS(th->th_urp); 329 } 330 331 /* 332 * ... and reverse the above. 333 */ 334 static void 335 tcp_fields_to_net(struct tcphdr *th) 336 { 337 338 HTONL(th->th_seq); 339 HTONL(th->th_ack); 340 HTONS(th->th_win); 341 HTONS(th->th_urp); 342 } 343 344 #ifdef TCP_CSUM_COUNTERS 345 #include <sys/device.h> 346 347 #if defined(INET) 348 extern struct evcnt tcp_hwcsum_ok; 349 extern struct evcnt tcp_hwcsum_bad; 350 extern struct evcnt tcp_hwcsum_data; 351 extern struct evcnt tcp_swcsum; 352 #endif /* defined(INET) */ 353 #if defined(INET6) 354 extern struct evcnt tcp6_hwcsum_ok; 355 extern struct evcnt tcp6_hwcsum_bad; 356 extern struct evcnt tcp6_hwcsum_data; 357 extern struct evcnt tcp6_swcsum; 358 #endif /* defined(INET6) */ 359 360 #define TCP_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 361 362 #else 363 364 #define TCP_CSUM_COUNTER_INCR(ev) /* nothing */ 365 366 #endif /* TCP_CSUM_COUNTERS */ 367 368 #ifdef TCP_REASS_COUNTERS 369 #include <sys/device.h> 370 371 extern struct evcnt tcp_reass_; 372 extern struct evcnt tcp_reass_empty; 373 extern struct evcnt tcp_reass_iteration[8]; 374 extern struct evcnt tcp_reass_prependfirst; 375 extern struct evcnt tcp_reass_prepend; 376 extern struct evcnt tcp_reass_insert; 377 extern struct evcnt tcp_reass_inserttail; 378 extern struct evcnt tcp_reass_append; 379 extern struct evcnt tcp_reass_appendtail; 380 extern struct evcnt tcp_reass_overlaptail; 381 extern struct evcnt tcp_reass_overlapfront; 382 extern struct evcnt tcp_reass_segdup; 383 extern struct evcnt tcp_reass_fragdup; 384 385 #define TCP_REASS_COUNTER_INCR(ev) (ev)->ev_count++ 386 387 #else 388 389 #define TCP_REASS_COUNTER_INCR(ev) /* nothing */ 390 391 #endif /* TCP_REASS_COUNTERS */ 392 393 static int tcp_reass(struct tcpcb *, const struct tcphdr *, struct mbuf *, 394 int *); 395 static int tcp_dooptions(struct tcpcb *, const u_char *, int, 396 struct tcphdr *, struct mbuf *, int, struct tcp_opt_info *); 397 398 #ifdef INET 399 static void tcp4_log_refused(const struct ip *, const struct tcphdr *); 400 #endif 401 #ifdef INET6 402 static void tcp6_log_refused(const struct ip6_hdr *, const struct tcphdr *); 403 #endif 404 405 #define TRAVERSE(x) while ((x)->m_next) (x) = (x)->m_next 406 407 #if defined(MBUFTRACE) 408 struct mowner tcp_reass_mowner = MOWNER_INIT("tcp", "reass"); 409 #endif /* defined(MBUFTRACE) */ 410 411 static POOL_INIT(tcpipqent_pool, sizeof(struct ipqent), 0, 0, 0, "tcpipqepl", 412 NULL, IPL_VM); 413 414 struct ipqent * 415 tcpipqent_alloc(void) 416 { 417 struct ipqent *ipqe; 418 int s; 419 420 s = splvm(); 421 ipqe = pool_get(&tcpipqent_pool, PR_NOWAIT); 422 splx(s); 423 424 return ipqe; 425 } 426 427 void 428 tcpipqent_free(struct ipqent *ipqe) 429 { 430 int s; 431 432 s = splvm(); 433 pool_put(&tcpipqent_pool, ipqe); 434 splx(s); 435 } 436 437 static int 438 tcp_reass(struct tcpcb *tp, const struct tcphdr *th, struct mbuf *m, int *tlen) 439 { 440 struct ipqent *p, *q, *nq, *tiqe = NULL; 441 struct socket *so = NULL; 442 int pkt_flags; 443 tcp_seq pkt_seq; 444 unsigned pkt_len; 445 u_long rcvpartdupbyte = 0; 446 u_long rcvoobyte; 447 #ifdef TCP_REASS_COUNTERS 448 u_int count = 0; 449 #endif 450 451 if (tp->t_inpcb) 452 so = tp->t_inpcb->inp_socket; 453 #ifdef INET6 454 else if (tp->t_in6pcb) 455 so = tp->t_in6pcb->in6p_socket; 456 #endif 457 458 TCP_REASS_LOCK_CHECK(tp); 459 460 /* 461 * Call with th==0 after become established to 462 * force pre-ESTABLISHED data up to user socket. 463 */ 464 if (th == 0) 465 goto present; 466 467 m_claimm(m, &tcp_reass_mowner); 468 469 rcvoobyte = *tlen; 470 /* 471 * Copy these to local variables because the tcpiphdr 472 * gets munged while we are collapsing mbufs. 473 */ 474 pkt_seq = th->th_seq; 475 pkt_len = *tlen; 476 pkt_flags = th->th_flags; 477 478 TCP_REASS_COUNTER_INCR(&tcp_reass_); 479 480 if ((p = TAILQ_LAST(&tp->segq, ipqehead)) != NULL) { 481 /* 482 * When we miss a packet, the vast majority of time we get 483 * packets that follow it in order. So optimize for that. 484 */ 485 if (pkt_seq == p->ipqe_seq + p->ipqe_len) { 486 p->ipqe_len += pkt_len; 487 p->ipqe_flags |= pkt_flags; 488 m_cat(p->ipre_mlast, m); 489 TRAVERSE(p->ipre_mlast); 490 m = NULL; 491 tiqe = p; 492 TAILQ_REMOVE(&tp->timeq, p, ipqe_timeq); 493 TCP_REASS_COUNTER_INCR(&tcp_reass_appendtail); 494 goto skip_replacement; 495 } 496 /* 497 * While we're here, if the pkt is completely beyond 498 * anything we have, just insert it at the tail. 499 */ 500 if (SEQ_GT(pkt_seq, p->ipqe_seq + p->ipqe_len)) { 501 TCP_REASS_COUNTER_INCR(&tcp_reass_inserttail); 502 goto insert_it; 503 } 504 } 505 506 q = TAILQ_FIRST(&tp->segq); 507 508 if (q != NULL) { 509 /* 510 * If this segment immediately precedes the first out-of-order 511 * block, simply slap the segment in front of it and (mostly) 512 * skip the complicated logic. 513 */ 514 if (pkt_seq + pkt_len == q->ipqe_seq) { 515 q->ipqe_seq = pkt_seq; 516 q->ipqe_len += pkt_len; 517 q->ipqe_flags |= pkt_flags; 518 m_cat(m, q->ipqe_m); 519 q->ipqe_m = m; 520 q->ipre_mlast = m; /* last mbuf may have changed */ 521 TRAVERSE(q->ipre_mlast); 522 tiqe = q; 523 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 524 TCP_REASS_COUNTER_INCR(&tcp_reass_prependfirst); 525 goto skip_replacement; 526 } 527 } else { 528 TCP_REASS_COUNTER_INCR(&tcp_reass_empty); 529 } 530 531 /* 532 * Find a segment which begins after this one does. 533 */ 534 for (p = NULL; q != NULL; q = nq) { 535 nq = TAILQ_NEXT(q, ipqe_q); 536 #ifdef TCP_REASS_COUNTERS 537 count++; 538 #endif 539 /* 540 * If the received segment is just right after this 541 * fragment, merge the two together and then check 542 * for further overlaps. 543 */ 544 if (q->ipqe_seq + q->ipqe_len == pkt_seq) { 545 #ifdef TCPREASS_DEBUG 546 printf("tcp_reass[%p]: concat %u:%u(%u) to %u:%u(%u)\n", 547 tp, pkt_seq, pkt_seq + pkt_len, pkt_len, 548 q->ipqe_seq, q->ipqe_seq + q->ipqe_len, q->ipqe_len); 549 #endif 550 pkt_len += q->ipqe_len; 551 pkt_flags |= q->ipqe_flags; 552 pkt_seq = q->ipqe_seq; 553 m_cat(q->ipre_mlast, m); 554 TRAVERSE(q->ipre_mlast); 555 m = q->ipqe_m; 556 TCP_REASS_COUNTER_INCR(&tcp_reass_append); 557 goto free_ipqe; 558 } 559 /* 560 * If the received segment is completely past this 561 * fragment, we need to go the next fragment. 562 */ 563 if (SEQ_LT(q->ipqe_seq + q->ipqe_len, pkt_seq)) { 564 p = q; 565 continue; 566 } 567 /* 568 * If the fragment is past the received segment, 569 * it (or any following) can't be concatenated. 570 */ 571 if (SEQ_GT(q->ipqe_seq, pkt_seq + pkt_len)) { 572 TCP_REASS_COUNTER_INCR(&tcp_reass_insert); 573 break; 574 } 575 576 /* 577 * We've received all the data in this segment before. 578 * mark it as a duplicate and return. 579 */ 580 if (SEQ_LEQ(q->ipqe_seq, pkt_seq) && 581 SEQ_GEQ(q->ipqe_seq + q->ipqe_len, pkt_seq + pkt_len)) { 582 tcpstat.tcps_rcvduppack++; 583 tcpstat.tcps_rcvdupbyte += pkt_len; 584 tcp_new_dsack(tp, pkt_seq, pkt_len); 585 m_freem(m); 586 if (tiqe != NULL) { 587 tcpipqent_free(tiqe); 588 } 589 TCP_REASS_COUNTER_INCR(&tcp_reass_segdup); 590 return (0); 591 } 592 /* 593 * Received segment completely overlaps this fragment 594 * so we drop the fragment (this keeps the temporal 595 * ordering of segments correct). 596 */ 597 if (SEQ_GEQ(q->ipqe_seq, pkt_seq) && 598 SEQ_LEQ(q->ipqe_seq + q->ipqe_len, pkt_seq + pkt_len)) { 599 rcvpartdupbyte += q->ipqe_len; 600 m_freem(q->ipqe_m); 601 TCP_REASS_COUNTER_INCR(&tcp_reass_fragdup); 602 goto free_ipqe; 603 } 604 /* 605 * RX'ed segment extends past the end of the 606 * fragment. Drop the overlapping bytes. Then 607 * merge the fragment and segment then treat as 608 * a longer received packet. 609 */ 610 if (SEQ_LT(q->ipqe_seq, pkt_seq) && 611 SEQ_GT(q->ipqe_seq + q->ipqe_len, pkt_seq)) { 612 int overlap = q->ipqe_seq + q->ipqe_len - pkt_seq; 613 #ifdef TCPREASS_DEBUG 614 printf("tcp_reass[%p]: trim starting %d bytes of %u:%u(%u)\n", 615 tp, overlap, 616 pkt_seq, pkt_seq + pkt_len, pkt_len); 617 #endif 618 m_adj(m, overlap); 619 rcvpartdupbyte += overlap; 620 m_cat(q->ipre_mlast, m); 621 TRAVERSE(q->ipre_mlast); 622 m = q->ipqe_m; 623 pkt_seq = q->ipqe_seq; 624 pkt_len += q->ipqe_len - overlap; 625 rcvoobyte -= overlap; 626 TCP_REASS_COUNTER_INCR(&tcp_reass_overlaptail); 627 goto free_ipqe; 628 } 629 /* 630 * RX'ed segment extends past the front of the 631 * fragment. Drop the overlapping bytes on the 632 * received packet. The packet will then be 633 * contatentated with this fragment a bit later. 634 */ 635 if (SEQ_GT(q->ipqe_seq, pkt_seq) && 636 SEQ_LT(q->ipqe_seq, pkt_seq + pkt_len)) { 637 int overlap = pkt_seq + pkt_len - q->ipqe_seq; 638 #ifdef TCPREASS_DEBUG 639 printf("tcp_reass[%p]: trim trailing %d bytes of %u:%u(%u)\n", 640 tp, overlap, 641 pkt_seq, pkt_seq + pkt_len, pkt_len); 642 #endif 643 m_adj(m, -overlap); 644 pkt_len -= overlap; 645 rcvpartdupbyte += overlap; 646 TCP_REASS_COUNTER_INCR(&tcp_reass_overlapfront); 647 rcvoobyte -= overlap; 648 } 649 /* 650 * If the received segment immediates precedes this 651 * fragment then tack the fragment onto this segment 652 * and reinsert the data. 653 */ 654 if (q->ipqe_seq == pkt_seq + pkt_len) { 655 #ifdef TCPREASS_DEBUG 656 printf("tcp_reass[%p]: append %u:%u(%u) to %u:%u(%u)\n", 657 tp, q->ipqe_seq, q->ipqe_seq + q->ipqe_len, q->ipqe_len, 658 pkt_seq, pkt_seq + pkt_len, pkt_len); 659 #endif 660 pkt_len += q->ipqe_len; 661 pkt_flags |= q->ipqe_flags; 662 m_cat(m, q->ipqe_m); 663 TAILQ_REMOVE(&tp->segq, q, ipqe_q); 664 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 665 tp->t_segqlen--; 666 KASSERT(tp->t_segqlen >= 0); 667 KASSERT(tp->t_segqlen != 0 || 668 (TAILQ_EMPTY(&tp->segq) && 669 TAILQ_EMPTY(&tp->timeq))); 670 if (tiqe == NULL) { 671 tiqe = q; 672 } else { 673 tcpipqent_free(q); 674 } 675 TCP_REASS_COUNTER_INCR(&tcp_reass_prepend); 676 break; 677 } 678 /* 679 * If the fragment is before the segment, remember it. 680 * When this loop is terminated, p will contain the 681 * pointer to fragment that is right before the received 682 * segment. 683 */ 684 if (SEQ_LEQ(q->ipqe_seq, pkt_seq)) 685 p = q; 686 687 continue; 688 689 /* 690 * This is a common operation. It also will allow 691 * to save doing a malloc/free in most instances. 692 */ 693 free_ipqe: 694 TAILQ_REMOVE(&tp->segq, q, ipqe_q); 695 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 696 tp->t_segqlen--; 697 KASSERT(tp->t_segqlen >= 0); 698 KASSERT(tp->t_segqlen != 0 || 699 (TAILQ_EMPTY(&tp->segq) && TAILQ_EMPTY(&tp->timeq))); 700 if (tiqe == NULL) { 701 tiqe = q; 702 } else { 703 tcpipqent_free(q); 704 } 705 } 706 707 #ifdef TCP_REASS_COUNTERS 708 if (count > 7) 709 TCP_REASS_COUNTER_INCR(&tcp_reass_iteration[0]); 710 else if (count > 0) 711 TCP_REASS_COUNTER_INCR(&tcp_reass_iteration[count]); 712 #endif 713 714 insert_it: 715 716 /* 717 * Allocate a new queue entry since the received segment did not 718 * collapse onto any other out-of-order block; thus we are allocating 719 * a new block. If it had collapsed, tiqe would not be NULL and 720 * we would be reusing it. 721 * XXX If we can't, just drop the packet. XXX 722 */ 723 if (tiqe == NULL) { 724 tiqe = tcpipqent_alloc(); 725 if (tiqe == NULL) { 726 tcpstat.tcps_rcvmemdrop++; 727 m_freem(m); 728 return (0); 729 } 730 } 731 732 /* 733 * Update the counters. 734 */ 735 tcpstat.tcps_rcvoopack++; 736 tcpstat.tcps_rcvoobyte += rcvoobyte; 737 if (rcvpartdupbyte) { 738 tcpstat.tcps_rcvpartduppack++; 739 tcpstat.tcps_rcvpartdupbyte += rcvpartdupbyte; 740 } 741 742 /* 743 * Insert the new fragment queue entry into both queues. 744 */ 745 tiqe->ipqe_m = m; 746 tiqe->ipre_mlast = m; 747 tiqe->ipqe_seq = pkt_seq; 748 tiqe->ipqe_len = pkt_len; 749 tiqe->ipqe_flags = pkt_flags; 750 if (p == NULL) { 751 TAILQ_INSERT_HEAD(&tp->segq, tiqe, ipqe_q); 752 #ifdef TCPREASS_DEBUG 753 if (tiqe->ipqe_seq != tp->rcv_nxt) 754 printf("tcp_reass[%p]: insert %u:%u(%u) at front\n", 755 tp, pkt_seq, pkt_seq + pkt_len, pkt_len); 756 #endif 757 } else { 758 TAILQ_INSERT_AFTER(&tp->segq, p, tiqe, ipqe_q); 759 #ifdef TCPREASS_DEBUG 760 printf("tcp_reass[%p]: insert %u:%u(%u) after %u:%u(%u)\n", 761 tp, pkt_seq, pkt_seq + pkt_len, pkt_len, 762 p->ipqe_seq, p->ipqe_seq + p->ipqe_len, p->ipqe_len); 763 #endif 764 } 765 tp->t_segqlen++; 766 767 skip_replacement: 768 769 TAILQ_INSERT_HEAD(&tp->timeq, tiqe, ipqe_timeq); 770 771 present: 772 /* 773 * Present data to user, advancing rcv_nxt through 774 * completed sequence space. 775 */ 776 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 777 return (0); 778 q = TAILQ_FIRST(&tp->segq); 779 if (q == NULL || q->ipqe_seq != tp->rcv_nxt) 780 return (0); 781 if (tp->t_state == TCPS_SYN_RECEIVED && q->ipqe_len) 782 return (0); 783 784 tp->rcv_nxt += q->ipqe_len; 785 pkt_flags = q->ipqe_flags & TH_FIN; 786 nd6_hint(tp); 787 788 TAILQ_REMOVE(&tp->segq, q, ipqe_q); 789 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 790 tp->t_segqlen--; 791 KASSERT(tp->t_segqlen >= 0); 792 KASSERT(tp->t_segqlen != 0 || 793 (TAILQ_EMPTY(&tp->segq) && TAILQ_EMPTY(&tp->timeq))); 794 if (so->so_state & SS_CANTRCVMORE) 795 m_freem(q->ipqe_m); 796 else 797 sbappendstream(&so->so_rcv, q->ipqe_m); 798 tcpipqent_free(q); 799 sorwakeup(so); 800 return (pkt_flags); 801 } 802 803 #ifdef INET6 804 int 805 tcp6_input(struct mbuf **mp, int *offp, int proto) 806 { 807 struct mbuf *m = *mp; 808 809 /* 810 * draft-itojun-ipv6-tcp-to-anycast 811 * better place to put this in? 812 */ 813 if (m->m_flags & M_ANYCAST6) { 814 struct ip6_hdr *ip6; 815 if (m->m_len < sizeof(struct ip6_hdr)) { 816 if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) { 817 tcpstat.tcps_rcvshort++; 818 return IPPROTO_DONE; 819 } 820 } 821 ip6 = mtod(m, struct ip6_hdr *); 822 icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR, 823 (char *)&ip6->ip6_dst - (char *)ip6); 824 return IPPROTO_DONE; 825 } 826 827 tcp_input(m, *offp, proto); 828 return IPPROTO_DONE; 829 } 830 #endif 831 832 #ifdef INET 833 static void 834 tcp4_log_refused(const struct ip *ip, const struct tcphdr *th) 835 { 836 char src[4*sizeof "123"]; 837 char dst[4*sizeof "123"]; 838 839 if (ip) { 840 strlcpy(src, inet_ntoa(ip->ip_src), sizeof(src)); 841 strlcpy(dst, inet_ntoa(ip->ip_dst), sizeof(dst)); 842 } 843 else { 844 strlcpy(src, "(unknown)", sizeof(src)); 845 strlcpy(dst, "(unknown)", sizeof(dst)); 846 } 847 log(LOG_INFO, 848 "Connection attempt to TCP %s:%d from %s:%d\n", 849 dst, ntohs(th->th_dport), 850 src, ntohs(th->th_sport)); 851 } 852 #endif 853 854 #ifdef INET6 855 static void 856 tcp6_log_refused(const struct ip6_hdr *ip6, const struct tcphdr *th) 857 { 858 char src[INET6_ADDRSTRLEN]; 859 char dst[INET6_ADDRSTRLEN]; 860 861 if (ip6) { 862 strlcpy(src, ip6_sprintf(&ip6->ip6_src), sizeof(src)); 863 strlcpy(dst, ip6_sprintf(&ip6->ip6_dst), sizeof(dst)); 864 } 865 else { 866 strlcpy(src, "(unknown v6)", sizeof(src)); 867 strlcpy(dst, "(unknown v6)", sizeof(dst)); 868 } 869 log(LOG_INFO, 870 "Connection attempt to TCP [%s]:%d from [%s]:%d\n", 871 dst, ntohs(th->th_dport), 872 src, ntohs(th->th_sport)); 873 } 874 #endif 875 876 /* 877 * Checksum extended TCP header and data. 878 */ 879 int 880 tcp_input_checksum(int af, struct mbuf *m, const struct tcphdr *th, 881 int toff, int off, int tlen) 882 { 883 884 /* 885 * XXX it's better to record and check if this mbuf is 886 * already checked. 887 */ 888 889 switch (af) { 890 #ifdef INET 891 case AF_INET: 892 switch (m->m_pkthdr.csum_flags & 893 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_TCPv4) | 894 M_CSUM_TCP_UDP_BAD | M_CSUM_DATA)) { 895 case M_CSUM_TCPv4|M_CSUM_TCP_UDP_BAD: 896 TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_bad); 897 goto badcsum; 898 899 case M_CSUM_TCPv4|M_CSUM_DATA: { 900 u_int32_t hw_csum = m->m_pkthdr.csum_data; 901 902 TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_data); 903 if (m->m_pkthdr.csum_flags & M_CSUM_NO_PSEUDOHDR) { 904 const struct ip *ip = 905 mtod(m, const struct ip *); 906 907 hw_csum = in_cksum_phdr(ip->ip_src.s_addr, 908 ip->ip_dst.s_addr, 909 htons(hw_csum + tlen + off + IPPROTO_TCP)); 910 } 911 if ((hw_csum ^ 0xffff) != 0) 912 goto badcsum; 913 break; 914 } 915 916 case M_CSUM_TCPv4: 917 /* Checksum was okay. */ 918 TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_ok); 919 break; 920 921 default: 922 /* 923 * Must compute it ourselves. Maybe skip checksum 924 * on loopback interfaces. 925 */ 926 if (__predict_true(!(m->m_pkthdr.rcvif->if_flags & 927 IFF_LOOPBACK) || 928 tcp_do_loopback_cksum)) { 929 TCP_CSUM_COUNTER_INCR(&tcp_swcsum); 930 if (in4_cksum(m, IPPROTO_TCP, toff, 931 tlen + off) != 0) 932 goto badcsum; 933 } 934 break; 935 } 936 break; 937 #endif /* INET4 */ 938 939 #ifdef INET6 940 case AF_INET6: 941 switch (m->m_pkthdr.csum_flags & 942 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_TCPv6) | 943 M_CSUM_TCP_UDP_BAD | M_CSUM_DATA)) { 944 case M_CSUM_TCPv6|M_CSUM_TCP_UDP_BAD: 945 TCP_CSUM_COUNTER_INCR(&tcp6_hwcsum_bad); 946 goto badcsum; 947 948 #if 0 /* notyet */ 949 case M_CSUM_TCPv6|M_CSUM_DATA: 950 #endif 951 952 case M_CSUM_TCPv6: 953 /* Checksum was okay. */ 954 TCP_CSUM_COUNTER_INCR(&tcp6_hwcsum_ok); 955 break; 956 957 default: 958 /* 959 * Must compute it ourselves. Maybe skip checksum 960 * on loopback interfaces. 961 */ 962 if (__predict_true((m->m_flags & M_LOOP) == 0 || 963 tcp_do_loopback_cksum)) { 964 TCP_CSUM_COUNTER_INCR(&tcp6_swcsum); 965 if (in6_cksum(m, IPPROTO_TCP, toff, 966 tlen + off) != 0) 967 goto badcsum; 968 } 969 } 970 break; 971 #endif /* INET6 */ 972 } 973 974 return 0; 975 976 badcsum: 977 tcpstat.tcps_rcvbadsum++; 978 return -1; 979 } 980 981 /* 982 * TCP input routine, follows pages 65-76 of RFC 793 very closely. 983 */ 984 void 985 tcp_input(struct mbuf *m, ...) 986 { 987 struct tcphdr *th; 988 struct ip *ip; 989 struct inpcb *inp; 990 #ifdef INET6 991 struct ip6_hdr *ip6; 992 struct in6pcb *in6p; 993 #endif 994 u_int8_t *optp = NULL; 995 int optlen = 0; 996 int len, tlen, toff, hdroptlen = 0; 997 struct tcpcb *tp = 0; 998 int tiflags; 999 struct socket *so = NULL; 1000 int todrop, dupseg, acked, ourfinisacked, needoutput = 0; 1001 #ifdef TCP_DEBUG 1002 short ostate = 0; 1003 #endif 1004 u_long tiwin; 1005 struct tcp_opt_info opti; 1006 int off, iphlen; 1007 va_list ap; 1008 int af; /* af on the wire */ 1009 struct mbuf *tcp_saveti = NULL; 1010 uint32_t ts_rtt; 1011 uint8_t iptos; 1012 1013 MCLAIM(m, &tcp_rx_mowner); 1014 va_start(ap, m); 1015 toff = va_arg(ap, int); 1016 (void)va_arg(ap, int); /* ignore value, advance ap */ 1017 va_end(ap); 1018 1019 tcpstat.tcps_rcvtotal++; 1020 1021 bzero(&opti, sizeof(opti)); 1022 opti.ts_present = 0; 1023 opti.maxseg = 0; 1024 1025 /* 1026 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN. 1027 * 1028 * TCP is, by definition, unicast, so we reject all 1029 * multicast outright. 1030 * 1031 * Note, there are additional src/dst address checks in 1032 * the AF-specific code below. 1033 */ 1034 if (m->m_flags & (M_BCAST|M_MCAST)) { 1035 /* XXX stat */ 1036 goto drop; 1037 } 1038 #ifdef INET6 1039 if (m->m_flags & M_ANYCAST6) { 1040 /* XXX stat */ 1041 goto drop; 1042 } 1043 #endif 1044 1045 /* 1046 * Get IP and TCP header. 1047 * Note: IP leaves IP header in first mbuf. 1048 */ 1049 ip = mtod(m, struct ip *); 1050 #ifdef INET6 1051 ip6 = NULL; 1052 #endif 1053 switch (ip->ip_v) { 1054 #ifdef INET 1055 case 4: 1056 af = AF_INET; 1057 iphlen = sizeof(struct ip); 1058 ip = mtod(m, struct ip *); 1059 IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, 1060 sizeof(struct tcphdr)); 1061 if (th == NULL) { 1062 tcpstat.tcps_rcvshort++; 1063 return; 1064 } 1065 /* We do the checksum after PCB lookup... */ 1066 len = ntohs(ip->ip_len); 1067 tlen = len - toff; 1068 iptos = ip->ip_tos; 1069 break; 1070 #endif 1071 #ifdef INET6 1072 case 6: 1073 ip = NULL; 1074 iphlen = sizeof(struct ip6_hdr); 1075 af = AF_INET6; 1076 ip6 = mtod(m, struct ip6_hdr *); 1077 IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, 1078 sizeof(struct tcphdr)); 1079 if (th == NULL) { 1080 tcpstat.tcps_rcvshort++; 1081 return; 1082 } 1083 1084 /* Be proactive about malicious use of IPv4 mapped address */ 1085 if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) || 1086 IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) { 1087 /* XXX stat */ 1088 goto drop; 1089 } 1090 1091 /* 1092 * Be proactive about unspecified IPv6 address in source. 1093 * As we use all-zero to indicate unbounded/unconnected pcb, 1094 * unspecified IPv6 address can be used to confuse us. 1095 * 1096 * Note that packets with unspecified IPv6 destination is 1097 * already dropped in ip6_input. 1098 */ 1099 if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 1100 /* XXX stat */ 1101 goto drop; 1102 } 1103 1104 /* 1105 * Make sure destination address is not multicast. 1106 * Source address checked in ip6_input(). 1107 */ 1108 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) { 1109 /* XXX stat */ 1110 goto drop; 1111 } 1112 1113 /* We do the checksum after PCB lookup... */ 1114 len = m->m_pkthdr.len; 1115 tlen = len - toff; 1116 iptos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 1117 break; 1118 #endif 1119 default: 1120 m_freem(m); 1121 return; 1122 } 1123 1124 KASSERT(TCP_HDR_ALIGNED_P(th)); 1125 1126 /* 1127 * Check that TCP offset makes sense, 1128 * pull out TCP options and adjust length. XXX 1129 */ 1130 off = th->th_off << 2; 1131 if (off < sizeof (struct tcphdr) || off > tlen) { 1132 tcpstat.tcps_rcvbadoff++; 1133 goto drop; 1134 } 1135 tlen -= off; 1136 1137 /* 1138 * tcp_input() has been modified to use tlen to mean the TCP data 1139 * length throughout the function. Other functions can use 1140 * m->m_pkthdr.len as the basis for calculating the TCP data length. 1141 * rja 1142 */ 1143 1144 if (off > sizeof (struct tcphdr)) { 1145 IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, off); 1146 if (th == NULL) { 1147 tcpstat.tcps_rcvshort++; 1148 return; 1149 } 1150 /* 1151 * NOTE: ip/ip6 will not be affected by m_pulldown() 1152 * (as they're before toff) and we don't need to update those. 1153 */ 1154 KASSERT(TCP_HDR_ALIGNED_P(th)); 1155 optlen = off - sizeof (struct tcphdr); 1156 optp = ((u_int8_t *)th) + sizeof(struct tcphdr); 1157 /* 1158 * Do quick retrieval of timestamp options ("options 1159 * prediction?"). If timestamp is the only option and it's 1160 * formatted as recommended in RFC 1323 appendix A, we 1161 * quickly get the values now and not bother calling 1162 * tcp_dooptions(), etc. 1163 */ 1164 if ((optlen == TCPOLEN_TSTAMP_APPA || 1165 (optlen > TCPOLEN_TSTAMP_APPA && 1166 optp[TCPOLEN_TSTAMP_APPA] == TCPOPT_EOL)) && 1167 *(u_int32_t *)optp == htonl(TCPOPT_TSTAMP_HDR) && 1168 (th->th_flags & TH_SYN) == 0) { 1169 opti.ts_present = 1; 1170 opti.ts_val = ntohl(*(u_int32_t *)(optp + 4)); 1171 opti.ts_ecr = ntohl(*(u_int32_t *)(optp + 8)); 1172 optp = NULL; /* we've parsed the options */ 1173 } 1174 } 1175 tiflags = th->th_flags; 1176 1177 /* 1178 * Locate pcb for segment. 1179 */ 1180 findpcb: 1181 inp = NULL; 1182 #ifdef INET6 1183 in6p = NULL; 1184 #endif 1185 switch (af) { 1186 #ifdef INET 1187 case AF_INET: 1188 inp = in_pcblookup_connect(&tcbtable, ip->ip_src, th->th_sport, 1189 ip->ip_dst, th->th_dport); 1190 if (inp == 0) { 1191 ++tcpstat.tcps_pcbhashmiss; 1192 inp = in_pcblookup_bind(&tcbtable, ip->ip_dst, th->th_dport); 1193 } 1194 #ifdef INET6 1195 if (inp == 0) { 1196 struct in6_addr s, d; 1197 1198 /* mapped addr case */ 1199 bzero(&s, sizeof(s)); 1200 s.s6_addr16[5] = htons(0xffff); 1201 bcopy(&ip->ip_src, &s.s6_addr32[3], sizeof(ip->ip_src)); 1202 bzero(&d, sizeof(d)); 1203 d.s6_addr16[5] = htons(0xffff); 1204 bcopy(&ip->ip_dst, &d.s6_addr32[3], sizeof(ip->ip_dst)); 1205 in6p = in6_pcblookup_connect(&tcbtable, &s, 1206 th->th_sport, &d, th->th_dport, 0); 1207 if (in6p == 0) { 1208 ++tcpstat.tcps_pcbhashmiss; 1209 in6p = in6_pcblookup_bind(&tcbtable, &d, 1210 th->th_dport, 0); 1211 } 1212 } 1213 #endif 1214 #ifndef INET6 1215 if (inp == 0) 1216 #else 1217 if (inp == 0 && in6p == 0) 1218 #endif 1219 { 1220 ++tcpstat.tcps_noport; 1221 if (tcp_log_refused && 1222 (tiflags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN) { 1223 tcp4_log_refused(ip, th); 1224 } 1225 tcp_fields_to_host(th); 1226 goto dropwithreset_ratelim; 1227 } 1228 #if defined(IPSEC) || defined(FAST_IPSEC) 1229 if (inp && (inp->inp_socket->so_options & SO_ACCEPTCONN) == 0 && 1230 ipsec4_in_reject(m, inp)) { 1231 ipsecstat.in_polvio++; 1232 goto drop; 1233 } 1234 #ifdef INET6 1235 else if (in6p && 1236 (in6p->in6p_socket->so_options & SO_ACCEPTCONN) == 0 && 1237 ipsec6_in_reject_so(m, in6p->in6p_socket)) { 1238 ipsecstat.in_polvio++; 1239 goto drop; 1240 } 1241 #endif 1242 #endif /*IPSEC*/ 1243 break; 1244 #endif /*INET*/ 1245 #ifdef INET6 1246 case AF_INET6: 1247 { 1248 int faith; 1249 1250 #if defined(NFAITH) && NFAITH > 0 1251 faith = faithprefix(&ip6->ip6_dst); 1252 #else 1253 faith = 0; 1254 #endif 1255 in6p = in6_pcblookup_connect(&tcbtable, &ip6->ip6_src, 1256 th->th_sport, &ip6->ip6_dst, th->th_dport, faith); 1257 if (in6p == NULL) { 1258 ++tcpstat.tcps_pcbhashmiss; 1259 in6p = in6_pcblookup_bind(&tcbtable, &ip6->ip6_dst, 1260 th->th_dport, faith); 1261 } 1262 if (in6p == NULL) { 1263 ++tcpstat.tcps_noport; 1264 if (tcp_log_refused && 1265 (tiflags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN) { 1266 tcp6_log_refused(ip6, th); 1267 } 1268 tcp_fields_to_host(th); 1269 goto dropwithreset_ratelim; 1270 } 1271 #if defined(IPSEC) || defined(FAST_IPSEC) 1272 if ((in6p->in6p_socket->so_options & SO_ACCEPTCONN) == 0 && 1273 ipsec6_in_reject(m, in6p)) { 1274 ipsec6stat.in_polvio++; 1275 goto drop; 1276 } 1277 #endif /*IPSEC*/ 1278 break; 1279 } 1280 #endif 1281 } 1282 1283 /* 1284 * If the state is CLOSED (i.e., TCB does not exist) then 1285 * all data in the incoming segment is discarded. 1286 * If the TCB exists but is in CLOSED state, it is embryonic, 1287 * but should either do a listen or a connect soon. 1288 */ 1289 tp = NULL; 1290 so = NULL; 1291 if (inp) { 1292 tp = intotcpcb(inp); 1293 so = inp->inp_socket; 1294 } 1295 #ifdef INET6 1296 else if (in6p) { 1297 tp = in6totcpcb(in6p); 1298 so = in6p->in6p_socket; 1299 } 1300 #endif 1301 if (tp == 0) { 1302 tcp_fields_to_host(th); 1303 goto dropwithreset_ratelim; 1304 } 1305 if (tp->t_state == TCPS_CLOSED) 1306 goto drop; 1307 1308 /* 1309 * Checksum extended TCP header and data. 1310 */ 1311 if (tcp_input_checksum(af, m, th, toff, off, tlen)) 1312 goto badcsum; 1313 1314 tcp_fields_to_host(th); 1315 1316 /* Unscale the window into a 32-bit value. */ 1317 if ((tiflags & TH_SYN) == 0) 1318 tiwin = th->th_win << tp->snd_scale; 1319 else 1320 tiwin = th->th_win; 1321 1322 #ifdef INET6 1323 /* save packet options if user wanted */ 1324 if (in6p && (in6p->in6p_flags & IN6P_CONTROLOPTS)) { 1325 if (in6p->in6p_options) { 1326 m_freem(in6p->in6p_options); 1327 in6p->in6p_options = 0; 1328 } 1329 KASSERT(ip6 != NULL); 1330 ip6_savecontrol(in6p, &in6p->in6p_options, ip6, m); 1331 } 1332 #endif 1333 1334 if (so->so_options & (SO_DEBUG|SO_ACCEPTCONN)) { 1335 union syn_cache_sa src; 1336 union syn_cache_sa dst; 1337 1338 bzero(&src, sizeof(src)); 1339 bzero(&dst, sizeof(dst)); 1340 switch (af) { 1341 #ifdef INET 1342 case AF_INET: 1343 src.sin.sin_len = sizeof(struct sockaddr_in); 1344 src.sin.sin_family = AF_INET; 1345 src.sin.sin_addr = ip->ip_src; 1346 src.sin.sin_port = th->th_sport; 1347 1348 dst.sin.sin_len = sizeof(struct sockaddr_in); 1349 dst.sin.sin_family = AF_INET; 1350 dst.sin.sin_addr = ip->ip_dst; 1351 dst.sin.sin_port = th->th_dport; 1352 break; 1353 #endif 1354 #ifdef INET6 1355 case AF_INET6: 1356 src.sin6.sin6_len = sizeof(struct sockaddr_in6); 1357 src.sin6.sin6_family = AF_INET6; 1358 src.sin6.sin6_addr = ip6->ip6_src; 1359 src.sin6.sin6_port = th->th_sport; 1360 1361 dst.sin6.sin6_len = sizeof(struct sockaddr_in6); 1362 dst.sin6.sin6_family = AF_INET6; 1363 dst.sin6.sin6_addr = ip6->ip6_dst; 1364 dst.sin6.sin6_port = th->th_dport; 1365 break; 1366 #endif /* INET6 */ 1367 default: 1368 goto badsyn; /*sanity*/ 1369 } 1370 1371 if (so->so_options & SO_DEBUG) { 1372 #ifdef TCP_DEBUG 1373 ostate = tp->t_state; 1374 #endif 1375 1376 tcp_saveti = NULL; 1377 if (iphlen + sizeof(struct tcphdr) > MHLEN) 1378 goto nosave; 1379 1380 if (m->m_len > iphlen && (m->m_flags & M_EXT) == 0) { 1381 tcp_saveti = m_copym(m, 0, iphlen, M_DONTWAIT); 1382 if (!tcp_saveti) 1383 goto nosave; 1384 } else { 1385 MGETHDR(tcp_saveti, M_DONTWAIT, MT_HEADER); 1386 if (!tcp_saveti) 1387 goto nosave; 1388 MCLAIM(m, &tcp_mowner); 1389 tcp_saveti->m_len = iphlen; 1390 m_copydata(m, 0, iphlen, 1391 mtod(tcp_saveti, void *)); 1392 } 1393 1394 if (M_TRAILINGSPACE(tcp_saveti) < sizeof(struct tcphdr)) { 1395 m_freem(tcp_saveti); 1396 tcp_saveti = NULL; 1397 } else { 1398 tcp_saveti->m_len += sizeof(struct tcphdr); 1399 memcpy(mtod(tcp_saveti, char *) + iphlen, th, 1400 sizeof(struct tcphdr)); 1401 } 1402 nosave:; 1403 } 1404 if (so->so_options & SO_ACCEPTCONN) { 1405 if ((tiflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) { 1406 if (tiflags & TH_RST) { 1407 syn_cache_reset(&src.sa, &dst.sa, th); 1408 } else if ((tiflags & (TH_ACK|TH_SYN)) == 1409 (TH_ACK|TH_SYN)) { 1410 /* 1411 * Received a SYN,ACK. This should 1412 * never happen while we are in 1413 * LISTEN. Send an RST. 1414 */ 1415 goto badsyn; 1416 } else if (tiflags & TH_ACK) { 1417 so = syn_cache_get(&src.sa, &dst.sa, 1418 th, toff, tlen, so, m); 1419 if (so == NULL) { 1420 /* 1421 * We don't have a SYN for 1422 * this ACK; send an RST. 1423 */ 1424 goto badsyn; 1425 } else if (so == 1426 (struct socket *)(-1)) { 1427 /* 1428 * We were unable to create 1429 * the connection. If the 1430 * 3-way handshake was 1431 * completed, and RST has 1432 * been sent to the peer. 1433 * Since the mbuf might be 1434 * in use for the reply, 1435 * do not free it. 1436 */ 1437 m = NULL; 1438 } else { 1439 /* 1440 * We have created a 1441 * full-blown connection. 1442 */ 1443 tp = NULL; 1444 inp = NULL; 1445 #ifdef INET6 1446 in6p = NULL; 1447 #endif 1448 switch (so->so_proto->pr_domain->dom_family) { 1449 #ifdef INET 1450 case AF_INET: 1451 inp = sotoinpcb(so); 1452 tp = intotcpcb(inp); 1453 break; 1454 #endif 1455 #ifdef INET6 1456 case AF_INET6: 1457 in6p = sotoin6pcb(so); 1458 tp = in6totcpcb(in6p); 1459 break; 1460 #endif 1461 } 1462 if (tp == NULL) 1463 goto badsyn; /*XXX*/ 1464 tiwin <<= tp->snd_scale; 1465 goto after_listen; 1466 } 1467 } else { 1468 /* 1469 * None of RST, SYN or ACK was set. 1470 * This is an invalid packet for a 1471 * TCB in LISTEN state. Send a RST. 1472 */ 1473 goto badsyn; 1474 } 1475 } else { 1476 /* 1477 * Received a SYN. 1478 * 1479 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN 1480 */ 1481 if (m->m_flags & (M_BCAST|M_MCAST)) 1482 goto drop; 1483 1484 switch (af) { 1485 #ifdef INET6 1486 case AF_INET6: 1487 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) 1488 goto drop; 1489 break; 1490 #endif /* INET6 */ 1491 case AF_INET: 1492 if (IN_MULTICAST(ip->ip_dst.s_addr) || 1493 in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) 1494 goto drop; 1495 break; 1496 } 1497 1498 #ifdef INET6 1499 /* 1500 * If deprecated address is forbidden, we do 1501 * not accept SYN to deprecated interface 1502 * address to prevent any new inbound 1503 * connection from getting established. 1504 * When we do not accept SYN, we send a TCP 1505 * RST, with deprecated source address (instead 1506 * of dropping it). We compromise it as it is 1507 * much better for peer to send a RST, and 1508 * RST will be the final packet for the 1509 * exchange. 1510 * 1511 * If we do not forbid deprecated addresses, we 1512 * accept the SYN packet. RFC2462 does not 1513 * suggest dropping SYN in this case. 1514 * If we decipher RFC2462 5.5.4, it says like 1515 * this: 1516 * 1. use of deprecated addr with existing 1517 * communication is okay - "SHOULD continue 1518 * to be used" 1519 * 2. use of it with new communication: 1520 * (2a) "SHOULD NOT be used if alternate 1521 * address with sufficient scope is 1522 * available" 1523 * (2b) nothing mentioned otherwise. 1524 * Here we fall into (2b) case as we have no 1525 * choice in our source address selection - we 1526 * must obey the peer. 1527 * 1528 * The wording in RFC2462 is confusing, and 1529 * there are multiple description text for 1530 * deprecated address handling - worse, they 1531 * are not exactly the same. I believe 5.5.4 1532 * is the best one, so we follow 5.5.4. 1533 */ 1534 if (af == AF_INET6 && !ip6_use_deprecated) { 1535 struct in6_ifaddr *ia6; 1536 if ((ia6 = in6ifa_ifpwithaddr(m->m_pkthdr.rcvif, 1537 &ip6->ip6_dst)) && 1538 (ia6->ia6_flags & IN6_IFF_DEPRECATED)) { 1539 tp = NULL; 1540 goto dropwithreset; 1541 } 1542 } 1543 #endif 1544 1545 #if defined(IPSEC) || defined(FAST_IPSEC) 1546 switch (af) { 1547 #ifdef INET 1548 case AF_INET: 1549 if (ipsec4_in_reject_so(m, so)) { 1550 ipsecstat.in_polvio++; 1551 tp = NULL; 1552 goto dropwithreset; 1553 } 1554 break; 1555 #endif 1556 #ifdef INET6 1557 case AF_INET6: 1558 if (ipsec6_in_reject_so(m, so)) { 1559 ipsec6stat.in_polvio++; 1560 tp = NULL; 1561 goto dropwithreset; 1562 } 1563 break; 1564 #endif /*INET6*/ 1565 } 1566 #endif /*IPSEC*/ 1567 1568 /* 1569 * LISTEN socket received a SYN 1570 * from itself? This can't possibly 1571 * be valid; drop the packet. 1572 */ 1573 if (th->th_sport == th->th_dport) { 1574 int i; 1575 1576 switch (af) { 1577 #ifdef INET 1578 case AF_INET: 1579 i = in_hosteq(ip->ip_src, ip->ip_dst); 1580 break; 1581 #endif 1582 #ifdef INET6 1583 case AF_INET6: 1584 i = IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &ip6->ip6_dst); 1585 break; 1586 #endif 1587 default: 1588 i = 1; 1589 } 1590 if (i) { 1591 tcpstat.tcps_badsyn++; 1592 goto drop; 1593 } 1594 } 1595 1596 /* 1597 * SYN looks ok; create compressed TCP 1598 * state for it. 1599 */ 1600 if (so->so_qlen <= so->so_qlimit && 1601 syn_cache_add(&src.sa, &dst.sa, th, tlen, 1602 so, m, optp, optlen, &opti)) 1603 m = NULL; 1604 } 1605 goto drop; 1606 } 1607 } 1608 1609 after_listen: 1610 #ifdef DIAGNOSTIC 1611 /* 1612 * Should not happen now that all embryonic connections 1613 * are handled with compressed state. 1614 */ 1615 if (tp->t_state == TCPS_LISTEN) 1616 panic("tcp_input: TCPS_LISTEN"); 1617 #endif 1618 1619 /* 1620 * Segment received on connection. 1621 * Reset idle time and keep-alive timer. 1622 */ 1623 tp->t_rcvtime = tcp_now; 1624 if (TCPS_HAVEESTABLISHED(tp->t_state)) 1625 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle); 1626 1627 /* 1628 * Process options. 1629 */ 1630 #ifdef TCP_SIGNATURE 1631 if (optp || (tp->t_flags & TF_SIGNATURE)) 1632 #else 1633 if (optp) 1634 #endif 1635 if (tcp_dooptions(tp, optp, optlen, th, m, toff, &opti) < 0) 1636 goto drop; 1637 1638 if (TCP_SACK_ENABLED(tp)) { 1639 tcp_del_sackholes(tp, th); 1640 } 1641 1642 if (TCP_ECN_ALLOWED(tp)) { 1643 switch (iptos & IPTOS_ECN_MASK) { 1644 case IPTOS_ECN_CE: 1645 tp->t_flags |= TF_ECN_SND_ECE; 1646 tcpstat.tcps_ecn_ce++; 1647 break; 1648 case IPTOS_ECN_ECT0: 1649 tcpstat.tcps_ecn_ect++; 1650 break; 1651 case IPTOS_ECN_ECT1: 1652 /* XXX: ignore for now -- rpaulo */ 1653 break; 1654 } 1655 1656 if (tiflags & TH_CWR) 1657 tp->t_flags &= ~TF_ECN_SND_ECE; 1658 1659 /* 1660 * Congestion experienced. 1661 * Ignore if we are already trying to recover. 1662 */ 1663 if ((tiflags & TH_ECE) && SEQ_GEQ(tp->snd_una, tp->snd_recover)) 1664 tp->t_congctl->cong_exp(tp); 1665 } 1666 1667 if (opti.ts_present && opti.ts_ecr) { 1668 /* 1669 * Calculate the RTT from the returned time stamp and the 1670 * connection's time base. If the time stamp is later than 1671 * the current time, or is extremely old, fall back to non-1323 1672 * RTT calculation. Since ts_ecr is unsigned, we can test both 1673 * at the same time. 1674 */ 1675 ts_rtt = TCP_TIMESTAMP(tp) - opti.ts_ecr + 1; 1676 if (ts_rtt > TCP_PAWS_IDLE) 1677 ts_rtt = 0; 1678 } else { 1679 ts_rtt = 0; 1680 } 1681 1682 /* 1683 * Header prediction: check for the two common cases 1684 * of a uni-directional data xfer. If the packet has 1685 * no control flags, is in-sequence, the window didn't 1686 * change and we're not retransmitting, it's a 1687 * candidate. If the length is zero and the ack moved 1688 * forward, we're the sender side of the xfer. Just 1689 * free the data acked & wake any higher level process 1690 * that was blocked waiting for space. If the length 1691 * is non-zero and the ack didn't move, we're the 1692 * receiver side. If we're getting packets in-order 1693 * (the reassembly queue is empty), add the data to 1694 * the socket buffer and note that we need a delayed ack. 1695 */ 1696 if (tp->t_state == TCPS_ESTABLISHED && 1697 (tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ECE|TH_CWR|TH_ACK)) 1698 == TH_ACK && 1699 (!opti.ts_present || TSTMP_GEQ(opti.ts_val, tp->ts_recent)) && 1700 th->th_seq == tp->rcv_nxt && 1701 tiwin && tiwin == tp->snd_wnd && 1702 tp->snd_nxt == tp->snd_max) { 1703 1704 /* 1705 * If last ACK falls within this segment's sequence numbers, 1706 * record the timestamp. 1707 * NOTE that the test is modified according to the latest 1708 * proposal of the tcplw@cray.com list (Braden 1993/04/26). 1709 * 1710 * note that we already know 1711 * TSTMP_GEQ(opti.ts_val, tp->ts_recent) 1712 */ 1713 if (opti.ts_present && 1714 SEQ_LEQ(th->th_seq, tp->last_ack_sent)) { 1715 tp->ts_recent_age = tcp_now; 1716 tp->ts_recent = opti.ts_val; 1717 } 1718 1719 if (tlen == 0) { 1720 /* Ack prediction. */ 1721 if (SEQ_GT(th->th_ack, tp->snd_una) && 1722 SEQ_LEQ(th->th_ack, tp->snd_max) && 1723 tp->snd_cwnd >= tp->snd_wnd && 1724 tp->t_partialacks < 0) { 1725 /* 1726 * this is a pure ack for outstanding data. 1727 */ 1728 ++tcpstat.tcps_predack; 1729 if (ts_rtt) 1730 tcp_xmit_timer(tp, ts_rtt); 1731 else if (tp->t_rtttime && 1732 SEQ_GT(th->th_ack, tp->t_rtseq)) 1733 tcp_xmit_timer(tp, 1734 tcp_now - tp->t_rtttime); 1735 acked = th->th_ack - tp->snd_una; 1736 tcpstat.tcps_rcvackpack++; 1737 tcpstat.tcps_rcvackbyte += acked; 1738 nd6_hint(tp); 1739 1740 if (acked > (tp->t_lastoff - tp->t_inoff)) 1741 tp->t_lastm = NULL; 1742 sbdrop(&so->so_snd, acked); 1743 tp->t_lastoff -= acked; 1744 1745 icmp_check(tp, th, acked); 1746 1747 tp->snd_una = th->th_ack; 1748 tp->snd_fack = tp->snd_una; 1749 if (SEQ_LT(tp->snd_high, tp->snd_una)) 1750 tp->snd_high = tp->snd_una; 1751 m_freem(m); 1752 1753 /* 1754 * If all outstanding data are acked, stop 1755 * retransmit timer, otherwise restart timer 1756 * using current (possibly backed-off) value. 1757 * If process is waiting for space, 1758 * wakeup/selnotify/signal. If data 1759 * are ready to send, let tcp_output 1760 * decide between more output or persist. 1761 */ 1762 if (tp->snd_una == tp->snd_max) 1763 TCP_TIMER_DISARM(tp, TCPT_REXMT); 1764 else if (TCP_TIMER_ISARMED(tp, 1765 TCPT_PERSIST) == 0) 1766 TCP_TIMER_ARM(tp, TCPT_REXMT, 1767 tp->t_rxtcur); 1768 1769 sowwakeup(so); 1770 if (so->so_snd.sb_cc) 1771 (void) tcp_output(tp); 1772 if (tcp_saveti) 1773 m_freem(tcp_saveti); 1774 return; 1775 } 1776 } else if (th->th_ack == tp->snd_una && 1777 TAILQ_FIRST(&tp->segq) == NULL && 1778 tlen <= sbspace(&so->so_rcv)) { 1779 int newsize = 0; /* automatic sockbuf scaling */ 1780 1781 /* 1782 * this is a pure, in-sequence data packet 1783 * with nothing on the reassembly queue and 1784 * we have enough buffer space to take it. 1785 */ 1786 ++tcpstat.tcps_preddat; 1787 tp->rcv_nxt += tlen; 1788 tcpstat.tcps_rcvpack++; 1789 tcpstat.tcps_rcvbyte += tlen; 1790 nd6_hint(tp); 1791 1792 /* 1793 * Automatic sizing enables the performance of large buffers 1794 * and most of the efficiency of small ones by only allocating 1795 * space when it is needed. 1796 * 1797 * On the receive side the socket buffer memory is only rarely 1798 * used to any significant extent. This allows us to be much 1799 * more aggressive in scaling the receive socket buffer. For 1800 * the case that the buffer space is actually used to a large 1801 * extent and we run out of kernel memory we can simply drop 1802 * the new segments; TCP on the sender will just retransmit it 1803 * later. Setting the buffer size too big may only consume too 1804 * much kernel memory if the application doesn't read() from 1805 * the socket or packet loss or reordering makes use of the 1806 * reassembly queue. 1807 * 1808 * The criteria to step up the receive buffer one notch are: 1809 * 1. the number of bytes received during the time it takes 1810 * one timestamp to be reflected back to us (the RTT); 1811 * 2. received bytes per RTT is within seven eighth of the 1812 * current socket buffer size; 1813 * 3. receive buffer size has not hit maximal automatic size; 1814 * 1815 * This algorithm does one step per RTT at most and only if 1816 * we receive a bulk stream w/o packet losses or reorderings. 1817 * Shrinking the buffer during idle times is not necessary as 1818 * it doesn't consume any memory when idle. 1819 * 1820 * TODO: Only step up if the application is actually serving 1821 * the buffer to better manage the socket buffer resources. 1822 */ 1823 if (tcp_do_autorcvbuf && 1824 opti.ts_ecr && 1825 (so->so_rcv.sb_flags & SB_AUTOSIZE)) { 1826 if (opti.ts_ecr > tp->rfbuf_ts && 1827 opti.ts_ecr - tp->rfbuf_ts < PR_SLOWHZ) { 1828 if (tp->rfbuf_cnt > 1829 (so->so_rcv.sb_hiwat / 8 * 7) && 1830 so->so_rcv.sb_hiwat < 1831 tcp_autorcvbuf_max) { 1832 newsize = 1833 min(so->so_rcv.sb_hiwat + 1834 tcp_autorcvbuf_inc, 1835 tcp_autorcvbuf_max); 1836 } 1837 /* Start over with next RTT. */ 1838 tp->rfbuf_ts = 0; 1839 tp->rfbuf_cnt = 0; 1840 } else 1841 tp->rfbuf_cnt += tlen; /* add up */ 1842 } 1843 1844 /* 1845 * Drop TCP, IP headers and TCP options then add data 1846 * to socket buffer. 1847 */ 1848 if (so->so_state & SS_CANTRCVMORE) 1849 m_freem(m); 1850 else { 1851 /* 1852 * Set new socket buffer size. 1853 * Give up when limit is reached. 1854 */ 1855 if (newsize) 1856 if (!sbreserve(&so->so_rcv, 1857 newsize, so)) 1858 so->so_rcv.sb_flags &= ~SB_AUTOSIZE; 1859 m_adj(m, toff + off); 1860 sbappendstream(&so->so_rcv, m); 1861 } 1862 sorwakeup(so); 1863 tcp_setup_ack(tp, th); 1864 if (tp->t_flags & TF_ACKNOW) 1865 (void) tcp_output(tp); 1866 if (tcp_saveti) 1867 m_freem(tcp_saveti); 1868 return; 1869 } 1870 } 1871 1872 /* 1873 * Compute mbuf offset to TCP data segment. 1874 */ 1875 hdroptlen = toff + off; 1876 1877 /* 1878 * Calculate amount of space in receive window, 1879 * and then do TCP input processing. 1880 * Receive window is amount of space in rcv queue, 1881 * but not less than advertised window. 1882 */ 1883 { int win; 1884 1885 win = sbspace(&so->so_rcv); 1886 if (win < 0) 1887 win = 0; 1888 tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt)); 1889 } 1890 1891 /* Reset receive buffer auto scaling when not in bulk receive mode. */ 1892 tp->rfbuf_ts = 0; 1893 tp->rfbuf_cnt = 0; 1894 1895 switch (tp->t_state) { 1896 /* 1897 * If the state is SYN_SENT: 1898 * if seg contains an ACK, but not for our SYN, drop the input. 1899 * if seg contains a RST, then drop the connection. 1900 * if seg does not contain SYN, then drop it. 1901 * Otherwise this is an acceptable SYN segment 1902 * initialize tp->rcv_nxt and tp->irs 1903 * if seg contains ack then advance tp->snd_una 1904 * if seg contains a ECE and ECN support is enabled, the stream 1905 * is ECN capable. 1906 * if SYN has been acked change to ESTABLISHED else SYN_RCVD state 1907 * arrange for segment to be acked (eventually) 1908 * continue processing rest of data/controls, beginning with URG 1909 */ 1910 case TCPS_SYN_SENT: 1911 if ((tiflags & TH_ACK) && 1912 (SEQ_LEQ(th->th_ack, tp->iss) || 1913 SEQ_GT(th->th_ack, tp->snd_max))) 1914 goto dropwithreset; 1915 if (tiflags & TH_RST) { 1916 if (tiflags & TH_ACK) 1917 tp = tcp_drop(tp, ECONNREFUSED); 1918 goto drop; 1919 } 1920 if ((tiflags & TH_SYN) == 0) 1921 goto drop; 1922 if (tiflags & TH_ACK) { 1923 tp->snd_una = th->th_ack; 1924 if (SEQ_LT(tp->snd_nxt, tp->snd_una)) 1925 tp->snd_nxt = tp->snd_una; 1926 if (SEQ_LT(tp->snd_high, tp->snd_una)) 1927 tp->snd_high = tp->snd_una; 1928 TCP_TIMER_DISARM(tp, TCPT_REXMT); 1929 1930 if ((tiflags & TH_ECE) && tcp_do_ecn) { 1931 tp->t_flags |= TF_ECN_PERMIT; 1932 tcpstat.tcps_ecn_shs++; 1933 } 1934 1935 } 1936 tp->irs = th->th_seq; 1937 tcp_rcvseqinit(tp); 1938 tp->t_flags |= TF_ACKNOW; 1939 tcp_mss_from_peer(tp, opti.maxseg); 1940 1941 /* 1942 * Initialize the initial congestion window. If we 1943 * had to retransmit the SYN, we must initialize cwnd 1944 * to 1 segment (i.e. the Loss Window). 1945 */ 1946 if (tp->t_flags & TF_SYN_REXMT) 1947 tp->snd_cwnd = tp->t_peermss; 1948 else { 1949 int ss = tcp_init_win; 1950 #ifdef INET 1951 if (inp != NULL && in_localaddr(inp->inp_faddr)) 1952 ss = tcp_init_win_local; 1953 #endif 1954 #ifdef INET6 1955 if (in6p != NULL && in6_localaddr(&in6p->in6p_faddr)) 1956 ss = tcp_init_win_local; 1957 #endif 1958 tp->snd_cwnd = TCP_INITIAL_WINDOW(ss, tp->t_peermss); 1959 } 1960 1961 tcp_rmx_rtt(tp); 1962 if (tiflags & TH_ACK) { 1963 tcpstat.tcps_connects++; 1964 soisconnected(so); 1965 tcp_established(tp); 1966 /* Do window scaling on this connection? */ 1967 if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == 1968 (TF_RCVD_SCALE|TF_REQ_SCALE)) { 1969 tp->snd_scale = tp->requested_s_scale; 1970 tp->rcv_scale = tp->request_r_scale; 1971 } 1972 TCP_REASS_LOCK(tp); 1973 (void) tcp_reass(tp, NULL, (struct mbuf *)0, &tlen); 1974 TCP_REASS_UNLOCK(tp); 1975 /* 1976 * if we didn't have to retransmit the SYN, 1977 * use its rtt as our initial srtt & rtt var. 1978 */ 1979 if (tp->t_rtttime) 1980 tcp_xmit_timer(tp, tcp_now - tp->t_rtttime); 1981 } else 1982 tp->t_state = TCPS_SYN_RECEIVED; 1983 1984 /* 1985 * Advance th->th_seq to correspond to first data byte. 1986 * If data, trim to stay within window, 1987 * dropping FIN if necessary. 1988 */ 1989 th->th_seq++; 1990 if (tlen > tp->rcv_wnd) { 1991 todrop = tlen - tp->rcv_wnd; 1992 m_adj(m, -todrop); 1993 tlen = tp->rcv_wnd; 1994 tiflags &= ~TH_FIN; 1995 tcpstat.tcps_rcvpackafterwin++; 1996 tcpstat.tcps_rcvbyteafterwin += todrop; 1997 } 1998 tp->snd_wl1 = th->th_seq - 1; 1999 tp->rcv_up = th->th_seq; 2000 goto step6; 2001 2002 /* 2003 * If the state is SYN_RECEIVED: 2004 * If seg contains an ACK, but not for our SYN, drop the input 2005 * and generate an RST. See page 36, rfc793 2006 */ 2007 case TCPS_SYN_RECEIVED: 2008 if ((tiflags & TH_ACK) && 2009 (SEQ_LEQ(th->th_ack, tp->iss) || 2010 SEQ_GT(th->th_ack, tp->snd_max))) 2011 goto dropwithreset; 2012 break; 2013 } 2014 2015 /* 2016 * States other than LISTEN or SYN_SENT. 2017 * First check timestamp, if present. 2018 * Then check that at least some bytes of segment are within 2019 * receive window. If segment begins before rcv_nxt, 2020 * drop leading data (and SYN); if nothing left, just ack. 2021 * 2022 * RFC 1323 PAWS: If we have a timestamp reply on this segment 2023 * and it's less than ts_recent, drop it. 2024 */ 2025 if (opti.ts_present && (tiflags & TH_RST) == 0 && tp->ts_recent && 2026 TSTMP_LT(opti.ts_val, tp->ts_recent)) { 2027 2028 /* Check to see if ts_recent is over 24 days old. */ 2029 if (tcp_now - tp->ts_recent_age > TCP_PAWS_IDLE) { 2030 /* 2031 * Invalidate ts_recent. If this segment updates 2032 * ts_recent, the age will be reset later and ts_recent 2033 * will get a valid value. If it does not, setting 2034 * ts_recent to zero will at least satisfy the 2035 * requirement that zero be placed in the timestamp 2036 * echo reply when ts_recent isn't valid. The 2037 * age isn't reset until we get a valid ts_recent 2038 * because we don't want out-of-order segments to be 2039 * dropped when ts_recent is old. 2040 */ 2041 tp->ts_recent = 0; 2042 } else { 2043 tcpstat.tcps_rcvduppack++; 2044 tcpstat.tcps_rcvdupbyte += tlen; 2045 tcpstat.tcps_pawsdrop++; 2046 tcp_new_dsack(tp, th->th_seq, tlen); 2047 goto dropafterack; 2048 } 2049 } 2050 2051 todrop = tp->rcv_nxt - th->th_seq; 2052 dupseg = false; 2053 if (todrop > 0) { 2054 if (tiflags & TH_SYN) { 2055 tiflags &= ~TH_SYN; 2056 th->th_seq++; 2057 if (th->th_urp > 1) 2058 th->th_urp--; 2059 else { 2060 tiflags &= ~TH_URG; 2061 th->th_urp = 0; 2062 } 2063 todrop--; 2064 } 2065 if (todrop > tlen || 2066 (todrop == tlen && (tiflags & TH_FIN) == 0)) { 2067 /* 2068 * Any valid FIN or RST must be to the left of the 2069 * window. At this point the FIN or RST must be a 2070 * duplicate or out of sequence; drop it. 2071 */ 2072 if (tiflags & TH_RST) 2073 goto drop; 2074 tiflags &= ~(TH_FIN|TH_RST); 2075 /* 2076 * Send an ACK to resynchronize and drop any data. 2077 * But keep on processing for RST or ACK. 2078 */ 2079 tp->t_flags |= TF_ACKNOW; 2080 todrop = tlen; 2081 dupseg = true; 2082 tcpstat.tcps_rcvdupbyte += todrop; 2083 tcpstat.tcps_rcvduppack++; 2084 } else if ((tiflags & TH_RST) && 2085 th->th_seq != tp->last_ack_sent) { 2086 /* 2087 * Test for reset before adjusting the sequence 2088 * number for overlapping data. 2089 */ 2090 goto dropafterack_ratelim; 2091 } else { 2092 tcpstat.tcps_rcvpartduppack++; 2093 tcpstat.tcps_rcvpartdupbyte += todrop; 2094 } 2095 tcp_new_dsack(tp, th->th_seq, todrop); 2096 hdroptlen += todrop; /*drop from head afterwards*/ 2097 th->th_seq += todrop; 2098 tlen -= todrop; 2099 if (th->th_urp > todrop) 2100 th->th_urp -= todrop; 2101 else { 2102 tiflags &= ~TH_URG; 2103 th->th_urp = 0; 2104 } 2105 } 2106 2107 /* 2108 * If new data are received on a connection after the 2109 * user processes are gone, then RST the other end. 2110 */ 2111 if ((so->so_state & SS_NOFDREF) && 2112 tp->t_state > TCPS_CLOSE_WAIT && tlen) { 2113 tp = tcp_close(tp); 2114 tcpstat.tcps_rcvafterclose++; 2115 goto dropwithreset; 2116 } 2117 2118 /* 2119 * If segment ends after window, drop trailing data 2120 * (and PUSH and FIN); if nothing left, just ACK. 2121 */ 2122 todrop = (th->th_seq + tlen) - (tp->rcv_nxt+tp->rcv_wnd); 2123 if (todrop > 0) { 2124 tcpstat.tcps_rcvpackafterwin++; 2125 if (todrop >= tlen) { 2126 /* 2127 * The segment actually starts after the window. 2128 * th->th_seq + tlen - tp->rcv_nxt - tp->rcv_wnd >= tlen 2129 * th->th_seq - tp->rcv_nxt - tp->rcv_wnd >= 0 2130 * th->th_seq >= tp->rcv_nxt + tp->rcv_wnd 2131 */ 2132 tcpstat.tcps_rcvbyteafterwin += tlen; 2133 /* 2134 * If a new connection request is received 2135 * while in TIME_WAIT, drop the old connection 2136 * and start over if the sequence numbers 2137 * are above the previous ones. 2138 * 2139 * NOTE: We will checksum the packet again, and 2140 * so we need to put the header fields back into 2141 * network order! 2142 * XXX This kind of sucks, but we don't expect 2143 * XXX this to happen very often, so maybe it 2144 * XXX doesn't matter so much. 2145 */ 2146 if (tiflags & TH_SYN && 2147 tp->t_state == TCPS_TIME_WAIT && 2148 SEQ_GT(th->th_seq, tp->rcv_nxt)) { 2149 tp = tcp_close(tp); 2150 tcp_fields_to_net(th); 2151 goto findpcb; 2152 } 2153 /* 2154 * If window is closed can only take segments at 2155 * window edge, and have to drop data and PUSH from 2156 * incoming segments. Continue processing, but 2157 * remember to ack. Otherwise, drop segment 2158 * and (if not RST) ack. 2159 */ 2160 if (tp->rcv_wnd == 0 && th->th_seq == tp->rcv_nxt) { 2161 tp->t_flags |= TF_ACKNOW; 2162 tcpstat.tcps_rcvwinprobe++; 2163 } else 2164 goto dropafterack; 2165 } else 2166 tcpstat.tcps_rcvbyteafterwin += todrop; 2167 m_adj(m, -todrop); 2168 tlen -= todrop; 2169 tiflags &= ~(TH_PUSH|TH_FIN); 2170 } 2171 2172 /* 2173 * If last ACK falls within this segment's sequence numbers, 2174 * record the timestamp. 2175 * NOTE: 2176 * 1) That the test incorporates suggestions from the latest 2177 * proposal of the tcplw@cray.com list (Braden 1993/04/26). 2178 * 2) That updating only on newer timestamps interferes with 2179 * our earlier PAWS tests, so this check should be solely 2180 * predicated on the sequence space of this segment. 2181 * 3) That we modify the segment boundary check to be 2182 * Last.ACK.Sent <= SEG.SEQ + SEG.Len 2183 * instead of RFC1323's 2184 * Last.ACK.Sent < SEG.SEQ + SEG.Len, 2185 * This modified check allows us to overcome RFC1323's 2186 * limitations as described in Stevens TCP/IP Illustrated 2187 * Vol. 2 p.869. In such cases, we can still calculate the 2188 * RTT correctly when RCV.NXT == Last.ACK.Sent. 2189 */ 2190 if (opti.ts_present && 2191 SEQ_LEQ(th->th_seq, tp->last_ack_sent) && 2192 SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + 2193 ((tiflags & (TH_SYN|TH_FIN)) != 0))) { 2194 tp->ts_recent_age = tcp_now; 2195 tp->ts_recent = opti.ts_val; 2196 } 2197 2198 /* 2199 * If the RST bit is set examine the state: 2200 * SYN_RECEIVED STATE: 2201 * If passive open, return to LISTEN state. 2202 * If active open, inform user that connection was refused. 2203 * ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES: 2204 * Inform user that connection was reset, and close tcb. 2205 * CLOSING, LAST_ACK, TIME_WAIT STATES 2206 * Close the tcb. 2207 */ 2208 if (tiflags & TH_RST) { 2209 if (th->th_seq != tp->last_ack_sent) 2210 goto dropafterack_ratelim; 2211 2212 switch (tp->t_state) { 2213 case TCPS_SYN_RECEIVED: 2214 so->so_error = ECONNREFUSED; 2215 goto close; 2216 2217 case TCPS_ESTABLISHED: 2218 case TCPS_FIN_WAIT_1: 2219 case TCPS_FIN_WAIT_2: 2220 case TCPS_CLOSE_WAIT: 2221 so->so_error = ECONNRESET; 2222 close: 2223 tp->t_state = TCPS_CLOSED; 2224 tcpstat.tcps_drops++; 2225 tp = tcp_close(tp); 2226 goto drop; 2227 2228 case TCPS_CLOSING: 2229 case TCPS_LAST_ACK: 2230 case TCPS_TIME_WAIT: 2231 tp = tcp_close(tp); 2232 goto drop; 2233 } 2234 } 2235 2236 /* 2237 * Since we've covered the SYN-SENT and SYN-RECEIVED states above 2238 * we must be in a synchronized state. RFC791 states (under RST 2239 * generation) that any unacceptable segment (an out-of-order SYN 2240 * qualifies) received in a synchronized state must elicit only an 2241 * empty acknowledgment segment ... and the connection remains in 2242 * the same state. 2243 */ 2244 if (tiflags & TH_SYN) { 2245 if (tp->rcv_nxt == th->th_seq) { 2246 tcp_respond(tp, m, m, th, (tcp_seq)0, th->th_ack - 1, 2247 TH_ACK); 2248 if (tcp_saveti) 2249 m_freem(tcp_saveti); 2250 return; 2251 } 2252 2253 goto dropafterack_ratelim; 2254 } 2255 2256 /* 2257 * If the ACK bit is off we drop the segment and return. 2258 */ 2259 if ((tiflags & TH_ACK) == 0) { 2260 if (tp->t_flags & TF_ACKNOW) 2261 goto dropafterack; 2262 else 2263 goto drop; 2264 } 2265 2266 /* 2267 * Ack processing. 2268 */ 2269 switch (tp->t_state) { 2270 2271 /* 2272 * In SYN_RECEIVED state if the ack ACKs our SYN then enter 2273 * ESTABLISHED state and continue processing, otherwise 2274 * send an RST. 2275 */ 2276 case TCPS_SYN_RECEIVED: 2277 if (SEQ_GT(tp->snd_una, th->th_ack) || 2278 SEQ_GT(th->th_ack, tp->snd_max)) 2279 goto dropwithreset; 2280 tcpstat.tcps_connects++; 2281 soisconnected(so); 2282 tcp_established(tp); 2283 /* Do window scaling? */ 2284 if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == 2285 (TF_RCVD_SCALE|TF_REQ_SCALE)) { 2286 tp->snd_scale = tp->requested_s_scale; 2287 tp->rcv_scale = tp->request_r_scale; 2288 } 2289 TCP_REASS_LOCK(tp); 2290 (void) tcp_reass(tp, NULL, (struct mbuf *)0, &tlen); 2291 TCP_REASS_UNLOCK(tp); 2292 tp->snd_wl1 = th->th_seq - 1; 2293 /* fall into ... */ 2294 2295 /* 2296 * In ESTABLISHED state: drop duplicate ACKs; ACK out of range 2297 * ACKs. If the ack is in the range 2298 * tp->snd_una < th->th_ack <= tp->snd_max 2299 * then advance tp->snd_una to th->th_ack and drop 2300 * data from the retransmission queue. If this ACK reflects 2301 * more up to date window information we update our window information. 2302 */ 2303 case TCPS_ESTABLISHED: 2304 case TCPS_FIN_WAIT_1: 2305 case TCPS_FIN_WAIT_2: 2306 case TCPS_CLOSE_WAIT: 2307 case TCPS_CLOSING: 2308 case TCPS_LAST_ACK: 2309 case TCPS_TIME_WAIT: 2310 2311 if (SEQ_LEQ(th->th_ack, tp->snd_una)) { 2312 if (tlen == 0 && !dupseg && tiwin == tp->snd_wnd) { 2313 tcpstat.tcps_rcvdupack++; 2314 /* 2315 * If we have outstanding data (other than 2316 * a window probe), this is a completely 2317 * duplicate ack (ie, window info didn't 2318 * change), the ack is the biggest we've 2319 * seen and we've seen exactly our rexmt 2320 * threshhold of them, assume a packet 2321 * has been dropped and retransmit it. 2322 * Kludge snd_nxt & the congestion 2323 * window so we send only this one 2324 * packet. 2325 */ 2326 if (TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0 || 2327 th->th_ack != tp->snd_una) 2328 tp->t_dupacks = 0; 2329 else if (tp->t_partialacks < 0 && 2330 (++tp->t_dupacks == tcprexmtthresh || 2331 TCP_FACK_FASTRECOV(tp))) { 2332 /* 2333 * Do the fast retransmit, and adjust 2334 * congestion control paramenters. 2335 */ 2336 if (tp->t_congctl->fast_retransmit(tp, th)) { 2337 /* False fast retransmit */ 2338 break; 2339 } else 2340 goto drop; 2341 } else if (tp->t_dupacks > tcprexmtthresh) { 2342 tp->snd_cwnd += tp->t_segsz; 2343 (void) tcp_output(tp); 2344 goto drop; 2345 } 2346 } else { 2347 /* 2348 * If the ack appears to be very old, only 2349 * allow data that is in-sequence. This 2350 * makes it somewhat more difficult to insert 2351 * forged data by guessing sequence numbers. 2352 * Sent an ack to try to update the send 2353 * sequence number on the other side. 2354 */ 2355 if (tlen && th->th_seq != tp->rcv_nxt && 2356 SEQ_LT(th->th_ack, 2357 tp->snd_una - tp->max_sndwnd)) 2358 goto dropafterack; 2359 } 2360 break; 2361 } 2362 /* 2363 * If the congestion window was inflated to account 2364 * for the other side's cached packets, retract it. 2365 */ 2366 /* XXX: make SACK have his own congestion control 2367 * struct -- rpaulo */ 2368 if (TCP_SACK_ENABLED(tp)) 2369 tcp_sack_newack(tp, th); 2370 else 2371 tp->t_congctl->fast_retransmit_newack(tp, th); 2372 if (SEQ_GT(th->th_ack, tp->snd_max)) { 2373 tcpstat.tcps_rcvacktoomuch++; 2374 goto dropafterack; 2375 } 2376 acked = th->th_ack - tp->snd_una; 2377 tcpstat.tcps_rcvackpack++; 2378 tcpstat.tcps_rcvackbyte += acked; 2379 2380 /* 2381 * If we have a timestamp reply, update smoothed 2382 * round trip time. If no timestamp is present but 2383 * transmit timer is running and timed sequence 2384 * number was acked, update smoothed round trip time. 2385 * Since we now have an rtt measurement, cancel the 2386 * timer backoff (cf., Phil Karn's retransmit alg.). 2387 * Recompute the initial retransmit timer. 2388 */ 2389 if (ts_rtt) 2390 tcp_xmit_timer(tp, ts_rtt); 2391 else if (tp->t_rtttime && SEQ_GT(th->th_ack, tp->t_rtseq)) 2392 tcp_xmit_timer(tp, tcp_now - tp->t_rtttime); 2393 2394 /* 2395 * If all outstanding data is acked, stop retransmit 2396 * timer and remember to restart (more output or persist). 2397 * If there is more data to be acked, restart retransmit 2398 * timer, using current (possibly backed-off) value. 2399 */ 2400 if (th->th_ack == tp->snd_max) { 2401 TCP_TIMER_DISARM(tp, TCPT_REXMT); 2402 needoutput = 1; 2403 } else if (TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) 2404 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 2405 2406 /* 2407 * New data has been acked, adjust the congestion window. 2408 */ 2409 tp->t_congctl->newack(tp, th); 2410 2411 nd6_hint(tp); 2412 if (acked > so->so_snd.sb_cc) { 2413 tp->snd_wnd -= so->so_snd.sb_cc; 2414 sbdrop(&so->so_snd, (int)so->so_snd.sb_cc); 2415 ourfinisacked = 1; 2416 } else { 2417 if (acked > (tp->t_lastoff - tp->t_inoff)) 2418 tp->t_lastm = NULL; 2419 sbdrop(&so->so_snd, acked); 2420 tp->t_lastoff -= acked; 2421 tp->snd_wnd -= acked; 2422 ourfinisacked = 0; 2423 } 2424 sowwakeup(so); 2425 2426 icmp_check(tp, th, acked); 2427 2428 tp->snd_una = th->th_ack; 2429 if (SEQ_GT(tp->snd_una, tp->snd_fack)) 2430 tp->snd_fack = tp->snd_una; 2431 if (SEQ_LT(tp->snd_nxt, tp->snd_una)) 2432 tp->snd_nxt = tp->snd_una; 2433 if (SEQ_LT(tp->snd_high, tp->snd_una)) 2434 tp->snd_high = tp->snd_una; 2435 2436 switch (tp->t_state) { 2437 2438 /* 2439 * In FIN_WAIT_1 STATE in addition to the processing 2440 * for the ESTABLISHED state if our FIN is now acknowledged 2441 * then enter FIN_WAIT_2. 2442 */ 2443 case TCPS_FIN_WAIT_1: 2444 if (ourfinisacked) { 2445 /* 2446 * If we can't receive any more 2447 * data, then closing user can proceed. 2448 * Starting the timer is contrary to the 2449 * specification, but if we don't get a FIN 2450 * we'll hang forever. 2451 */ 2452 if (so->so_state & SS_CANTRCVMORE) { 2453 soisdisconnected(so); 2454 if (tp->t_maxidle > 0) 2455 TCP_TIMER_ARM(tp, TCPT_2MSL, 2456 tp->t_maxidle); 2457 } 2458 tp->t_state = TCPS_FIN_WAIT_2; 2459 } 2460 break; 2461 2462 /* 2463 * In CLOSING STATE in addition to the processing for 2464 * the ESTABLISHED state if the ACK acknowledges our FIN 2465 * then enter the TIME-WAIT state, otherwise ignore 2466 * the segment. 2467 */ 2468 case TCPS_CLOSING: 2469 if (ourfinisacked) { 2470 tp->t_state = TCPS_TIME_WAIT; 2471 tcp_canceltimers(tp); 2472 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2473 soisdisconnected(so); 2474 } 2475 break; 2476 2477 /* 2478 * In LAST_ACK, we may still be waiting for data to drain 2479 * and/or to be acked, as well as for the ack of our FIN. 2480 * If our FIN is now acknowledged, delete the TCB, 2481 * enter the closed state and return. 2482 */ 2483 case TCPS_LAST_ACK: 2484 if (ourfinisacked) { 2485 tp = tcp_close(tp); 2486 goto drop; 2487 } 2488 break; 2489 2490 /* 2491 * In TIME_WAIT state the only thing that should arrive 2492 * is a retransmission of the remote FIN. Acknowledge 2493 * it and restart the finack timer. 2494 */ 2495 case TCPS_TIME_WAIT: 2496 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2497 goto dropafterack; 2498 } 2499 } 2500 2501 step6: 2502 /* 2503 * Update window information. 2504 * Don't look at window if no ACK: TAC's send garbage on first SYN. 2505 */ 2506 if ((tiflags & TH_ACK) && (SEQ_LT(tp->snd_wl1, th->th_seq) || 2507 (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) || 2508 (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) { 2509 /* keep track of pure window updates */ 2510 if (tlen == 0 && 2511 tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd) 2512 tcpstat.tcps_rcvwinupd++; 2513 tp->snd_wnd = tiwin; 2514 tp->snd_wl1 = th->th_seq; 2515 tp->snd_wl2 = th->th_ack; 2516 if (tp->snd_wnd > tp->max_sndwnd) 2517 tp->max_sndwnd = tp->snd_wnd; 2518 needoutput = 1; 2519 } 2520 2521 /* 2522 * Process segments with URG. 2523 */ 2524 if ((tiflags & TH_URG) && th->th_urp && 2525 TCPS_HAVERCVDFIN(tp->t_state) == 0) { 2526 /* 2527 * This is a kludge, but if we receive and accept 2528 * random urgent pointers, we'll crash in 2529 * soreceive. It's hard to imagine someone 2530 * actually wanting to send this much urgent data. 2531 */ 2532 if (th->th_urp + so->so_rcv.sb_cc > sb_max) { 2533 th->th_urp = 0; /* XXX */ 2534 tiflags &= ~TH_URG; /* XXX */ 2535 goto dodata; /* XXX */ 2536 } 2537 /* 2538 * If this segment advances the known urgent pointer, 2539 * then mark the data stream. This should not happen 2540 * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since 2541 * a FIN has been received from the remote side. 2542 * In these states we ignore the URG. 2543 * 2544 * According to RFC961 (Assigned Protocols), 2545 * the urgent pointer points to the last octet 2546 * of urgent data. We continue, however, 2547 * to consider it to indicate the first octet 2548 * of data past the urgent section as the original 2549 * spec states (in one of two places). 2550 */ 2551 if (SEQ_GT(th->th_seq+th->th_urp, tp->rcv_up)) { 2552 tp->rcv_up = th->th_seq + th->th_urp; 2553 so->so_oobmark = so->so_rcv.sb_cc + 2554 (tp->rcv_up - tp->rcv_nxt) - 1; 2555 if (so->so_oobmark == 0) 2556 so->so_state |= SS_RCVATMARK; 2557 sohasoutofband(so); 2558 tp->t_oobflags &= ~(TCPOOB_HAVEDATA | TCPOOB_HADDATA); 2559 } 2560 /* 2561 * Remove out of band data so doesn't get presented to user. 2562 * This can happen independent of advancing the URG pointer, 2563 * but if two URG's are pending at once, some out-of-band 2564 * data may creep in... ick. 2565 */ 2566 if (th->th_urp <= (u_int16_t) tlen 2567 #ifdef SO_OOBINLINE 2568 && (so->so_options & SO_OOBINLINE) == 0 2569 #endif 2570 ) 2571 tcp_pulloutofband(so, th, m, hdroptlen); 2572 } else 2573 /* 2574 * If no out of band data is expected, 2575 * pull receive urgent pointer along 2576 * with the receive window. 2577 */ 2578 if (SEQ_GT(tp->rcv_nxt, tp->rcv_up)) 2579 tp->rcv_up = tp->rcv_nxt; 2580 dodata: /* XXX */ 2581 2582 /* 2583 * Process the segment text, merging it into the TCP sequencing queue, 2584 * and arranging for acknowledgement of receipt if necessary. 2585 * This process logically involves adjusting tp->rcv_wnd as data 2586 * is presented to the user (this happens in tcp_usrreq.c, 2587 * case PRU_RCVD). If a FIN has already been received on this 2588 * connection then we just ignore the text. 2589 */ 2590 if ((tlen || (tiflags & TH_FIN)) && 2591 TCPS_HAVERCVDFIN(tp->t_state) == 0) { 2592 /* 2593 * Insert segment ti into reassembly queue of tcp with 2594 * control block tp. Return TH_FIN if reassembly now includes 2595 * a segment with FIN. The macro form does the common case 2596 * inline (segment is the next to be received on an 2597 * established connection, and the queue is empty), 2598 * avoiding linkage into and removal from the queue and 2599 * repetition of various conversions. 2600 * Set DELACK for segments received in order, but ack 2601 * immediately when segments are out of order 2602 * (so fast retransmit can work). 2603 */ 2604 /* NOTE: this was TCP_REASS() macro, but used only once */ 2605 TCP_REASS_LOCK(tp); 2606 if (th->th_seq == tp->rcv_nxt && 2607 TAILQ_FIRST(&tp->segq) == NULL && 2608 tp->t_state == TCPS_ESTABLISHED) { 2609 tcp_setup_ack(tp, th); 2610 tp->rcv_nxt += tlen; 2611 tiflags = th->th_flags & TH_FIN; 2612 tcpstat.tcps_rcvpack++; 2613 tcpstat.tcps_rcvbyte += tlen; 2614 nd6_hint(tp); 2615 if (so->so_state & SS_CANTRCVMORE) 2616 m_freem(m); 2617 else { 2618 m_adj(m, hdroptlen); 2619 sbappendstream(&(so)->so_rcv, m); 2620 } 2621 sorwakeup(so); 2622 } else { 2623 m_adj(m, hdroptlen); 2624 tiflags = tcp_reass(tp, th, m, &tlen); 2625 tp->t_flags |= TF_ACKNOW; 2626 } 2627 TCP_REASS_UNLOCK(tp); 2628 2629 /* 2630 * Note the amount of data that peer has sent into 2631 * our window, in order to estimate the sender's 2632 * buffer size. 2633 */ 2634 len = so->so_rcv.sb_hiwat - (tp->rcv_adv - tp->rcv_nxt); 2635 } else { 2636 m_freem(m); 2637 m = NULL; 2638 tiflags &= ~TH_FIN; 2639 } 2640 2641 /* 2642 * If FIN is received ACK the FIN and let the user know 2643 * that the connection is closing. Ignore a FIN received before 2644 * the connection is fully established. 2645 */ 2646 if ((tiflags & TH_FIN) && TCPS_HAVEESTABLISHED(tp->t_state)) { 2647 if (TCPS_HAVERCVDFIN(tp->t_state) == 0) { 2648 socantrcvmore(so); 2649 tp->t_flags |= TF_ACKNOW; 2650 tp->rcv_nxt++; 2651 } 2652 switch (tp->t_state) { 2653 2654 /* 2655 * In ESTABLISHED STATE enter the CLOSE_WAIT state. 2656 */ 2657 case TCPS_ESTABLISHED: 2658 tp->t_state = TCPS_CLOSE_WAIT; 2659 break; 2660 2661 /* 2662 * If still in FIN_WAIT_1 STATE FIN has not been acked so 2663 * enter the CLOSING state. 2664 */ 2665 case TCPS_FIN_WAIT_1: 2666 tp->t_state = TCPS_CLOSING; 2667 break; 2668 2669 /* 2670 * In FIN_WAIT_2 state enter the TIME_WAIT state, 2671 * starting the time-wait timer, turning off the other 2672 * standard timers. 2673 */ 2674 case TCPS_FIN_WAIT_2: 2675 tp->t_state = TCPS_TIME_WAIT; 2676 tcp_canceltimers(tp); 2677 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2678 soisdisconnected(so); 2679 break; 2680 2681 /* 2682 * In TIME_WAIT state restart the 2 MSL time_wait timer. 2683 */ 2684 case TCPS_TIME_WAIT: 2685 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2686 break; 2687 } 2688 } 2689 #ifdef TCP_DEBUG 2690 if (so->so_options & SO_DEBUG) 2691 tcp_trace(TA_INPUT, ostate, tp, tcp_saveti, 0); 2692 #endif 2693 2694 /* 2695 * Return any desired output. 2696 */ 2697 if (needoutput || (tp->t_flags & TF_ACKNOW)) { 2698 (void) tcp_output(tp); 2699 } 2700 if (tcp_saveti) 2701 m_freem(tcp_saveti); 2702 return; 2703 2704 badsyn: 2705 /* 2706 * Received a bad SYN. Increment counters and dropwithreset. 2707 */ 2708 tcpstat.tcps_badsyn++; 2709 tp = NULL; 2710 goto dropwithreset; 2711 2712 dropafterack: 2713 /* 2714 * Generate an ACK dropping incoming segment if it occupies 2715 * sequence space, where the ACK reflects our state. 2716 */ 2717 if (tiflags & TH_RST) 2718 goto drop; 2719 goto dropafterack2; 2720 2721 dropafterack_ratelim: 2722 /* 2723 * We may want to rate-limit ACKs against SYN/RST attack. 2724 */ 2725 if (ppsratecheck(&tcp_ackdrop_ppslim_last, &tcp_ackdrop_ppslim_count, 2726 tcp_ackdrop_ppslim) == 0) { 2727 /* XXX stat */ 2728 goto drop; 2729 } 2730 /* ...fall into dropafterack2... */ 2731 2732 dropafterack2: 2733 m_freem(m); 2734 tp->t_flags |= TF_ACKNOW; 2735 (void) tcp_output(tp); 2736 if (tcp_saveti) 2737 m_freem(tcp_saveti); 2738 return; 2739 2740 dropwithreset_ratelim: 2741 /* 2742 * We may want to rate-limit RSTs in certain situations, 2743 * particularly if we are sending an RST in response to 2744 * an attempt to connect to or otherwise communicate with 2745 * a port for which we have no socket. 2746 */ 2747 if (ppsratecheck(&tcp_rst_ppslim_last, &tcp_rst_ppslim_count, 2748 tcp_rst_ppslim) == 0) { 2749 /* XXX stat */ 2750 goto drop; 2751 } 2752 /* ...fall into dropwithreset... */ 2753 2754 dropwithreset: 2755 /* 2756 * Generate a RST, dropping incoming segment. 2757 * Make ACK acceptable to originator of segment. 2758 */ 2759 if (tiflags & TH_RST) 2760 goto drop; 2761 2762 switch (af) { 2763 #ifdef INET6 2764 case AF_INET6: 2765 /* For following calls to tcp_respond */ 2766 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) 2767 goto drop; 2768 break; 2769 #endif /* INET6 */ 2770 case AF_INET: 2771 if (IN_MULTICAST(ip->ip_dst.s_addr) || 2772 in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) 2773 goto drop; 2774 } 2775 2776 if (tiflags & TH_ACK) 2777 (void)tcp_respond(tp, m, m, th, (tcp_seq)0, th->th_ack, TH_RST); 2778 else { 2779 if (tiflags & TH_SYN) 2780 tlen++; 2781 (void)tcp_respond(tp, m, m, th, th->th_seq + tlen, (tcp_seq)0, 2782 TH_RST|TH_ACK); 2783 } 2784 if (tcp_saveti) 2785 m_freem(tcp_saveti); 2786 return; 2787 2788 badcsum: 2789 drop: 2790 /* 2791 * Drop space held by incoming segment and return. 2792 */ 2793 if (tp) { 2794 if (tp->t_inpcb) 2795 so = tp->t_inpcb->inp_socket; 2796 #ifdef INET6 2797 else if (tp->t_in6pcb) 2798 so = tp->t_in6pcb->in6p_socket; 2799 #endif 2800 else 2801 so = NULL; 2802 #ifdef TCP_DEBUG 2803 if (so && (so->so_options & SO_DEBUG) != 0) 2804 tcp_trace(TA_DROP, ostate, tp, tcp_saveti, 0); 2805 #endif 2806 } 2807 if (tcp_saveti) 2808 m_freem(tcp_saveti); 2809 m_freem(m); 2810 return; 2811 } 2812 2813 #ifdef TCP_SIGNATURE 2814 int 2815 tcp_signature_apply(void *fstate, void *data, u_int len) 2816 { 2817 2818 MD5Update(fstate, (u_char *)data, len); 2819 return (0); 2820 } 2821 2822 struct secasvar * 2823 tcp_signature_getsav(struct mbuf *m, struct tcphdr *th) 2824 { 2825 struct secasvar *sav; 2826 #ifdef FAST_IPSEC 2827 union sockaddr_union dst; 2828 #endif 2829 struct ip *ip; 2830 struct ip6_hdr *ip6; 2831 2832 ip = mtod(m, struct ip *); 2833 switch (ip->ip_v) { 2834 case 4: 2835 ip = mtod(m, struct ip *); 2836 ip6 = NULL; 2837 break; 2838 case 6: 2839 ip = NULL; 2840 ip6 = mtod(m, struct ip6_hdr *); 2841 break; 2842 default: 2843 return (NULL); 2844 } 2845 2846 #ifdef FAST_IPSEC 2847 /* Extract the destination from the IP header in the mbuf. */ 2848 bzero(&dst, sizeof(union sockaddr_union)); 2849 if (ip !=NULL) { 2850 dst.sa.sa_len = sizeof(struct sockaddr_in); 2851 dst.sa.sa_family = AF_INET; 2852 dst.sin.sin_addr = ip->ip_dst; 2853 } else { 2854 dst.sa.sa_len = sizeof(struct sockaddr_in6); 2855 dst.sa.sa_family = AF_INET6; 2856 dst.sin6.sin6_addr = ip6->ip6_dst; 2857 } 2858 2859 /* 2860 * Look up an SADB entry which matches the address of the peer. 2861 */ 2862 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2863 #else 2864 if (ip) 2865 sav = key_allocsa(AF_INET, (void *)&ip->ip_src, 2866 (void *)&ip->ip_dst, IPPROTO_TCP, 2867 htonl(TCP_SIG_SPI), 0, 0); 2868 else 2869 sav = key_allocsa(AF_INET6, (void *)&ip6->ip6_src, 2870 (void *)&ip6->ip6_dst, IPPROTO_TCP, 2871 htonl(TCP_SIG_SPI), 0, 0); 2872 #endif 2873 2874 return (sav); /* freesav must be performed by caller */ 2875 } 2876 2877 int 2878 tcp_signature(struct mbuf *m, struct tcphdr *th, int thoff, 2879 struct secasvar *sav, char *sig) 2880 { 2881 MD5_CTX ctx; 2882 struct ip *ip; 2883 struct ipovly *ipovly; 2884 struct ip6_hdr *ip6; 2885 struct ippseudo ippseudo; 2886 struct ip6_hdr_pseudo ip6pseudo; 2887 struct tcphdr th0; 2888 int l, tcphdrlen; 2889 2890 if (sav == NULL) 2891 return (-1); 2892 2893 tcphdrlen = th->th_off * 4; 2894 2895 switch (mtod(m, struct ip *)->ip_v) { 2896 case 4: 2897 ip = mtod(m, struct ip *); 2898 ip6 = NULL; 2899 break; 2900 case 6: 2901 ip = NULL; 2902 ip6 = mtod(m, struct ip6_hdr *); 2903 break; 2904 default: 2905 return (-1); 2906 } 2907 2908 MD5Init(&ctx); 2909 2910 if (ip) { 2911 memset(&ippseudo, 0, sizeof(ippseudo)); 2912 ipovly = (struct ipovly *)ip; 2913 ippseudo.ippseudo_src = ipovly->ih_src; 2914 ippseudo.ippseudo_dst = ipovly->ih_dst; 2915 ippseudo.ippseudo_pad = 0; 2916 ippseudo.ippseudo_p = IPPROTO_TCP; 2917 ippseudo.ippseudo_len = htons(m->m_pkthdr.len - thoff); 2918 MD5Update(&ctx, (char *)&ippseudo, sizeof(ippseudo)); 2919 } else { 2920 memset(&ip6pseudo, 0, sizeof(ip6pseudo)); 2921 ip6pseudo.ip6ph_src = ip6->ip6_src; 2922 in6_clearscope(&ip6pseudo.ip6ph_src); 2923 ip6pseudo.ip6ph_dst = ip6->ip6_dst; 2924 in6_clearscope(&ip6pseudo.ip6ph_dst); 2925 ip6pseudo.ip6ph_len = htons(m->m_pkthdr.len - thoff); 2926 ip6pseudo.ip6ph_nxt = IPPROTO_TCP; 2927 MD5Update(&ctx, (char *)&ip6pseudo, sizeof(ip6pseudo)); 2928 } 2929 2930 th0 = *th; 2931 th0.th_sum = 0; 2932 MD5Update(&ctx, (char *)&th0, sizeof(th0)); 2933 2934 l = m->m_pkthdr.len - thoff - tcphdrlen; 2935 if (l > 0) 2936 m_apply(m, thoff + tcphdrlen, 2937 m->m_pkthdr.len - thoff - tcphdrlen, 2938 tcp_signature_apply, &ctx); 2939 2940 MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); 2941 MD5Final(sig, &ctx); 2942 2943 return (0); 2944 } 2945 #endif 2946 2947 static int 2948 tcp_dooptions(struct tcpcb *tp, const u_char *cp, int cnt, 2949 struct tcphdr *th, 2950 struct mbuf *m, int toff, struct tcp_opt_info *oi) 2951 { 2952 u_int16_t mss; 2953 int opt, optlen = 0; 2954 #ifdef TCP_SIGNATURE 2955 void *sigp = NULL; 2956 char sigbuf[TCP_SIGLEN]; 2957 struct secasvar *sav = NULL; 2958 #endif 2959 2960 for (; cp && cnt > 0; cnt -= optlen, cp += optlen) { 2961 opt = cp[0]; 2962 if (opt == TCPOPT_EOL) 2963 break; 2964 if (opt == TCPOPT_NOP) 2965 optlen = 1; 2966 else { 2967 if (cnt < 2) 2968 break; 2969 optlen = cp[1]; 2970 if (optlen < 2 || optlen > cnt) 2971 break; 2972 } 2973 switch (opt) { 2974 2975 default: 2976 continue; 2977 2978 case TCPOPT_MAXSEG: 2979 if (optlen != TCPOLEN_MAXSEG) 2980 continue; 2981 if (!(th->th_flags & TH_SYN)) 2982 continue; 2983 if (TCPS_HAVERCVDSYN(tp->t_state)) 2984 continue; 2985 bcopy(cp + 2, &mss, sizeof(mss)); 2986 oi->maxseg = ntohs(mss); 2987 break; 2988 2989 case TCPOPT_WINDOW: 2990 if (optlen != TCPOLEN_WINDOW) 2991 continue; 2992 if (!(th->th_flags & TH_SYN)) 2993 continue; 2994 if (TCPS_HAVERCVDSYN(tp->t_state)) 2995 continue; 2996 tp->t_flags |= TF_RCVD_SCALE; 2997 tp->requested_s_scale = cp[2]; 2998 if (tp->requested_s_scale > TCP_MAX_WINSHIFT) { 2999 #if 0 /*XXX*/ 3000 char *p; 3001 3002 if (ip) 3003 p = ntohl(ip->ip_src); 3004 #ifdef INET6 3005 else if (ip6) 3006 p = ip6_sprintf(&ip6->ip6_src); 3007 #endif 3008 else 3009 p = "(unknown)"; 3010 log(LOG_ERR, "TCP: invalid wscale %d from %s, " 3011 "assuming %d\n", 3012 tp->requested_s_scale, p, 3013 TCP_MAX_WINSHIFT); 3014 #else 3015 log(LOG_ERR, "TCP: invalid wscale %d, " 3016 "assuming %d\n", 3017 tp->requested_s_scale, 3018 TCP_MAX_WINSHIFT); 3019 #endif 3020 tp->requested_s_scale = TCP_MAX_WINSHIFT; 3021 } 3022 break; 3023 3024 case TCPOPT_TIMESTAMP: 3025 if (optlen != TCPOLEN_TIMESTAMP) 3026 continue; 3027 oi->ts_present = 1; 3028 bcopy(cp + 2, &oi->ts_val, sizeof(oi->ts_val)); 3029 NTOHL(oi->ts_val); 3030 bcopy(cp + 6, &oi->ts_ecr, sizeof(oi->ts_ecr)); 3031 NTOHL(oi->ts_ecr); 3032 3033 if (!(th->th_flags & TH_SYN)) 3034 continue; 3035 if (TCPS_HAVERCVDSYN(tp->t_state)) 3036 continue; 3037 /* 3038 * A timestamp received in a SYN makes 3039 * it ok to send timestamp requests and replies. 3040 */ 3041 tp->t_flags |= TF_RCVD_TSTMP; 3042 tp->ts_recent = oi->ts_val; 3043 tp->ts_recent_age = tcp_now; 3044 break; 3045 3046 case TCPOPT_SACK_PERMITTED: 3047 if (optlen != TCPOLEN_SACK_PERMITTED) 3048 continue; 3049 if (!(th->th_flags & TH_SYN)) 3050 continue; 3051 if (TCPS_HAVERCVDSYN(tp->t_state)) 3052 continue; 3053 if (tcp_do_sack) { 3054 tp->t_flags |= TF_SACK_PERMIT; 3055 tp->t_flags |= TF_WILL_SACK; 3056 } 3057 break; 3058 3059 case TCPOPT_SACK: 3060 tcp_sack_option(tp, th, cp, optlen); 3061 break; 3062 #ifdef TCP_SIGNATURE 3063 case TCPOPT_SIGNATURE: 3064 if (optlen != TCPOLEN_SIGNATURE) 3065 continue; 3066 if (sigp && bcmp(sigp, cp + 2, TCP_SIGLEN)) 3067 return (-1); 3068 3069 sigp = sigbuf; 3070 memcpy(sigbuf, cp + 2, TCP_SIGLEN); 3071 tp->t_flags |= TF_SIGNATURE; 3072 break; 3073 #endif 3074 } 3075 } 3076 3077 #ifdef TCP_SIGNATURE 3078 if (tp->t_flags & TF_SIGNATURE) { 3079 3080 sav = tcp_signature_getsav(m, th); 3081 3082 if (sav == NULL && tp->t_state == TCPS_LISTEN) 3083 return (-1); 3084 } 3085 3086 if ((sigp ? TF_SIGNATURE : 0) ^ (tp->t_flags & TF_SIGNATURE)) { 3087 if (sav == NULL) 3088 return (-1); 3089 #ifdef FAST_IPSEC 3090 KEY_FREESAV(&sav); 3091 #else 3092 key_freesav(sav); 3093 #endif 3094 return (-1); 3095 } 3096 3097 if (sigp) { 3098 char sig[TCP_SIGLEN]; 3099 3100 tcp_fields_to_net(th); 3101 if (tcp_signature(m, th, toff, sav, sig) < 0) { 3102 tcp_fields_to_host(th); 3103 if (sav == NULL) 3104 return (-1); 3105 #ifdef FAST_IPSEC 3106 KEY_FREESAV(&sav); 3107 #else 3108 key_freesav(sav); 3109 #endif 3110 return (-1); 3111 } 3112 tcp_fields_to_host(th); 3113 3114 if (bcmp(sig, sigp, TCP_SIGLEN)) { 3115 tcpstat.tcps_badsig++; 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 } else 3125 tcpstat.tcps_goodsig++; 3126 3127 key_sa_recordxfer(sav, m); 3128 #ifdef FAST_IPSEC 3129 KEY_FREESAV(&sav); 3130 #else 3131 key_freesav(sav); 3132 #endif 3133 } 3134 #endif 3135 3136 return (0); 3137 } 3138 3139 /* 3140 * Pull out of band byte out of a segment so 3141 * it doesn't appear in the user's data queue. 3142 * It is still reflected in the segment length for 3143 * sequencing purposes. 3144 */ 3145 void 3146 tcp_pulloutofband(struct socket *so, struct tcphdr *th, 3147 struct mbuf *m, int off) 3148 { 3149 int cnt = off + th->th_urp - 1; 3150 3151 while (cnt >= 0) { 3152 if (m->m_len > cnt) { 3153 char *cp = mtod(m, char *) + cnt; 3154 struct tcpcb *tp = sototcpcb(so); 3155 3156 tp->t_iobc = *cp; 3157 tp->t_oobflags |= TCPOOB_HAVEDATA; 3158 bcopy(cp+1, cp, (unsigned)(m->m_len - cnt - 1)); 3159 m->m_len--; 3160 return; 3161 } 3162 cnt -= m->m_len; 3163 m = m->m_next; 3164 if (m == 0) 3165 break; 3166 } 3167 panic("tcp_pulloutofband"); 3168 } 3169 3170 /* 3171 * Collect new round-trip time estimate 3172 * and update averages and current timeout. 3173 */ 3174 void 3175 tcp_xmit_timer(struct tcpcb *tp, uint32_t rtt) 3176 { 3177 int32_t delta; 3178 3179 tcpstat.tcps_rttupdated++; 3180 if (tp->t_srtt != 0) { 3181 /* 3182 * srtt is stored as fixed point with 3 bits after the 3183 * binary point (i.e., scaled by 8). The following magic 3184 * is equivalent to the smoothing algorithm in rfc793 with 3185 * an alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed 3186 * point). Adjust rtt to origin 0. 3187 */ 3188 delta = (rtt << 2) - (tp->t_srtt >> TCP_RTT_SHIFT); 3189 if ((tp->t_srtt += delta) <= 0) 3190 tp->t_srtt = 1 << 2; 3191 /* 3192 * We accumulate a smoothed rtt variance (actually, a 3193 * smoothed mean difference), then set the retransmit 3194 * timer to smoothed rtt + 4 times the smoothed variance. 3195 * rttvar is stored as fixed point with 2 bits after the 3196 * binary point (scaled by 4). The following is 3197 * equivalent to rfc793 smoothing with an alpha of .75 3198 * (rttvar = rttvar*3/4 + |delta| / 4). This replaces 3199 * rfc793's wired-in beta. 3200 */ 3201 if (delta < 0) 3202 delta = -delta; 3203 delta -= (tp->t_rttvar >> TCP_RTTVAR_SHIFT); 3204 if ((tp->t_rttvar += delta) <= 0) 3205 tp->t_rttvar = 1 << 2; 3206 } else { 3207 /* 3208 * No rtt measurement yet - use the unsmoothed rtt. 3209 * Set the variance to half the rtt (so our first 3210 * retransmit happens at 3*rtt). 3211 */ 3212 tp->t_srtt = rtt << (TCP_RTT_SHIFT + 2); 3213 tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT + 2 - 1); 3214 } 3215 tp->t_rtttime = 0; 3216 tp->t_rxtshift = 0; 3217 3218 /* 3219 * the retransmit should happen at rtt + 4 * rttvar. 3220 * Because of the way we do the smoothing, srtt and rttvar 3221 * will each average +1/2 tick of bias. When we compute 3222 * the retransmit timer, we want 1/2 tick of rounding and 3223 * 1 extra tick because of +-1/2 tick uncertainty in the 3224 * firing of the timer. The bias will give us exactly the 3225 * 1.5 tick we need. But, because the bias is 3226 * statistical, we have to test that we don't drop below 3227 * the minimum feasible timer (which is 2 ticks). 3228 */ 3229 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 3230 max(tp->t_rttmin, rtt + 2), TCPTV_REXMTMAX); 3231 3232 /* 3233 * We received an ack for a packet that wasn't retransmitted; 3234 * it is probably safe to discard any error indications we've 3235 * received recently. This isn't quite right, but close enough 3236 * for now (a route might have failed after we sent a segment, 3237 * and the return path might not be symmetrical). 3238 */ 3239 tp->t_softerror = 0; 3240 } 3241 3242 3243 /* 3244 * TCP compressed state engine. Currently used to hold compressed 3245 * state for SYN_RECEIVED. 3246 */ 3247 3248 u_long syn_cache_count; 3249 u_int32_t syn_hash1, syn_hash2; 3250 3251 #define SYN_HASH(sa, sp, dp) \ 3252 ((((sa)->s_addr^syn_hash1)*(((((u_int32_t)(dp))<<16) + \ 3253 ((u_int32_t)(sp)))^syn_hash2))) 3254 #ifndef INET6 3255 #define SYN_HASHALL(hash, src, dst) \ 3256 do { \ 3257 hash = SYN_HASH(&((const struct sockaddr_in *)(src))->sin_addr, \ 3258 ((const struct sockaddr_in *)(src))->sin_port, \ 3259 ((const struct sockaddr_in *)(dst))->sin_port); \ 3260 } while (/*CONSTCOND*/ 0) 3261 #else 3262 #define SYN_HASH6(sa, sp, dp) \ 3263 ((((sa)->s6_addr32[0] ^ (sa)->s6_addr32[3] ^ syn_hash1) * \ 3264 (((((u_int32_t)(dp))<<16) + ((u_int32_t)(sp)))^syn_hash2)) \ 3265 & 0x7fffffff) 3266 3267 #define SYN_HASHALL(hash, src, dst) \ 3268 do { \ 3269 switch ((src)->sa_family) { \ 3270 case AF_INET: \ 3271 hash = SYN_HASH(&((const struct sockaddr_in *)(src))->sin_addr, \ 3272 ((const struct sockaddr_in *)(src))->sin_port, \ 3273 ((const struct sockaddr_in *)(dst))->sin_port); \ 3274 break; \ 3275 case AF_INET6: \ 3276 hash = SYN_HASH6(&((const struct sockaddr_in6 *)(src))->sin6_addr, \ 3277 ((const struct sockaddr_in6 *)(src))->sin6_port, \ 3278 ((const struct sockaddr_in6 *)(dst))->sin6_port); \ 3279 break; \ 3280 default: \ 3281 hash = 0; \ 3282 } \ 3283 } while (/*CONSTCOND*/0) 3284 #endif /* INET6 */ 3285 3286 POOL_INIT(syn_cache_pool, sizeof(struct syn_cache), 0, 0, 0, "synpl", NULL, 3287 IPL_SOFTNET); 3288 3289 /* 3290 * We don't estimate RTT with SYNs, so each packet starts with the default 3291 * RTT and each timer step has a fixed timeout value. 3292 */ 3293 #define SYN_CACHE_TIMER_ARM(sc) \ 3294 do { \ 3295 TCPT_RANGESET((sc)->sc_rxtcur, \ 3296 TCPTV_SRTTDFLT * tcp_backoff[(sc)->sc_rxtshift], TCPTV_MIN, \ 3297 TCPTV_REXMTMAX); \ 3298 callout_reset(&(sc)->sc_timer, \ 3299 (sc)->sc_rxtcur * (hz / PR_SLOWHZ), syn_cache_timer, (sc)); \ 3300 } while (/*CONSTCOND*/0) 3301 3302 #define SYN_CACHE_TIMESTAMP(sc) (tcp_now - (sc)->sc_timebase) 3303 3304 static inline void 3305 syn_cache_rm(struct syn_cache *sc) 3306 { 3307 TAILQ_REMOVE(&tcp_syn_cache[sc->sc_bucketidx].sch_bucket, 3308 sc, sc_bucketq); 3309 sc->sc_tp = NULL; 3310 LIST_REMOVE(sc, sc_tpq); 3311 tcp_syn_cache[sc->sc_bucketidx].sch_length--; 3312 callout_stop(&sc->sc_timer); 3313 syn_cache_count--; 3314 } 3315 3316 static inline void 3317 syn_cache_put(struct syn_cache *sc) 3318 { 3319 if (sc->sc_ipopts) 3320 (void) m_free(sc->sc_ipopts); 3321 rtcache_free(&sc->sc_route); 3322 if (callout_invoking(&sc->sc_timer)) 3323 sc->sc_flags |= SCF_DEAD; 3324 else { 3325 callout_destroy(&sc->sc_timer); 3326 pool_put(&syn_cache_pool, sc); 3327 } 3328 } 3329 3330 void 3331 syn_cache_init(void) 3332 { 3333 int i; 3334 3335 /* Initialize the hash buckets. */ 3336 for (i = 0; i < tcp_syn_cache_size; i++) 3337 TAILQ_INIT(&tcp_syn_cache[i].sch_bucket); 3338 } 3339 3340 void 3341 syn_cache_insert(struct syn_cache *sc, struct tcpcb *tp) 3342 { 3343 struct syn_cache_head *scp; 3344 struct syn_cache *sc2; 3345 int s; 3346 3347 /* 3348 * If there are no entries in the hash table, reinitialize 3349 * the hash secrets. 3350 */ 3351 if (syn_cache_count == 0) { 3352 syn_hash1 = arc4random(); 3353 syn_hash2 = arc4random(); 3354 } 3355 3356 SYN_HASHALL(sc->sc_hash, &sc->sc_src.sa, &sc->sc_dst.sa); 3357 sc->sc_bucketidx = sc->sc_hash % tcp_syn_cache_size; 3358 scp = &tcp_syn_cache[sc->sc_bucketidx]; 3359 3360 /* 3361 * Make sure that we don't overflow the per-bucket 3362 * limit or the total cache size limit. 3363 */ 3364 s = splsoftnet(); 3365 if (scp->sch_length >= tcp_syn_bucket_limit) { 3366 tcpstat.tcps_sc_bucketoverflow++; 3367 /* 3368 * The bucket is full. Toss the oldest element in the 3369 * bucket. This will be the first entry in the bucket. 3370 */ 3371 sc2 = TAILQ_FIRST(&scp->sch_bucket); 3372 #ifdef DIAGNOSTIC 3373 /* 3374 * This should never happen; we should always find an 3375 * entry in our bucket. 3376 */ 3377 if (sc2 == NULL) 3378 panic("syn_cache_insert: bucketoverflow: impossible"); 3379 #endif 3380 syn_cache_rm(sc2); 3381 syn_cache_put(sc2); /* calls pool_put but see spl above */ 3382 } else if (syn_cache_count >= tcp_syn_cache_limit) { 3383 struct syn_cache_head *scp2, *sce; 3384 3385 tcpstat.tcps_sc_overflowed++; 3386 /* 3387 * The cache is full. Toss the oldest entry in the 3388 * first non-empty bucket we can find. 3389 * 3390 * XXX We would really like to toss the oldest 3391 * entry in the cache, but we hope that this 3392 * condition doesn't happen very often. 3393 */ 3394 scp2 = scp; 3395 if (TAILQ_EMPTY(&scp2->sch_bucket)) { 3396 sce = &tcp_syn_cache[tcp_syn_cache_size]; 3397 for (++scp2; scp2 != scp; scp2++) { 3398 if (scp2 >= sce) 3399 scp2 = &tcp_syn_cache[0]; 3400 if (! TAILQ_EMPTY(&scp2->sch_bucket)) 3401 break; 3402 } 3403 #ifdef DIAGNOSTIC 3404 /* 3405 * This should never happen; we should always find a 3406 * non-empty bucket. 3407 */ 3408 if (scp2 == scp) 3409 panic("syn_cache_insert: cacheoverflow: " 3410 "impossible"); 3411 #endif 3412 } 3413 sc2 = TAILQ_FIRST(&scp2->sch_bucket); 3414 syn_cache_rm(sc2); 3415 syn_cache_put(sc2); /* calls pool_put but see spl above */ 3416 } 3417 3418 /* 3419 * Initialize the entry's timer. 3420 */ 3421 sc->sc_rxttot = 0; 3422 sc->sc_rxtshift = 0; 3423 SYN_CACHE_TIMER_ARM(sc); 3424 3425 /* Link it from tcpcb entry */ 3426 LIST_INSERT_HEAD(&tp->t_sc, sc, sc_tpq); 3427 3428 /* Put it into the bucket. */ 3429 TAILQ_INSERT_TAIL(&scp->sch_bucket, sc, sc_bucketq); 3430 scp->sch_length++; 3431 syn_cache_count++; 3432 3433 tcpstat.tcps_sc_added++; 3434 splx(s); 3435 } 3436 3437 /* 3438 * Walk the timer queues, looking for SYN,ACKs that need to be retransmitted. 3439 * If we have retransmitted an entry the maximum number of times, expire 3440 * that entry. 3441 */ 3442 void 3443 syn_cache_timer(void *arg) 3444 { 3445 struct syn_cache *sc = arg; 3446 int s; 3447 3448 s = splsoftnet(); 3449 callout_ack(&sc->sc_timer); 3450 3451 if (__predict_false(sc->sc_flags & SCF_DEAD)) { 3452 tcpstat.tcps_sc_delayed_free++; 3453 callout_destroy(&sc->sc_timer); 3454 pool_put(&syn_cache_pool, sc); 3455 splx(s); 3456 return; 3457 } 3458 3459 if (__predict_false(sc->sc_rxtshift == TCP_MAXRXTSHIFT)) { 3460 /* Drop it -- too many retransmissions. */ 3461 goto dropit; 3462 } 3463 3464 /* 3465 * Compute the total amount of time this entry has 3466 * been on a queue. If this entry has been on longer 3467 * than the keep alive timer would allow, expire it. 3468 */ 3469 sc->sc_rxttot += sc->sc_rxtcur; 3470 if (sc->sc_rxttot >= tcp_keepinit) 3471 goto dropit; 3472 3473 tcpstat.tcps_sc_retransmitted++; 3474 (void) syn_cache_respond(sc, NULL); 3475 3476 /* Advance the timer back-off. */ 3477 sc->sc_rxtshift++; 3478 SYN_CACHE_TIMER_ARM(sc); 3479 3480 splx(s); 3481 return; 3482 3483 dropit: 3484 tcpstat.tcps_sc_timed_out++; 3485 syn_cache_rm(sc); 3486 syn_cache_put(sc); /* calls pool_put but see spl above */ 3487 splx(s); 3488 } 3489 3490 /* 3491 * Remove syn cache created by the specified tcb entry, 3492 * because this does not make sense to keep them 3493 * (if there's no tcb entry, syn cache entry will never be used) 3494 */ 3495 void 3496 syn_cache_cleanup(struct tcpcb *tp) 3497 { 3498 struct syn_cache *sc, *nsc; 3499 int s; 3500 3501 s = splsoftnet(); 3502 3503 for (sc = LIST_FIRST(&tp->t_sc); sc != NULL; sc = nsc) { 3504 nsc = LIST_NEXT(sc, sc_tpq); 3505 3506 #ifdef DIAGNOSTIC 3507 if (sc->sc_tp != tp) 3508 panic("invalid sc_tp in syn_cache_cleanup"); 3509 #endif 3510 syn_cache_rm(sc); 3511 syn_cache_put(sc); /* calls pool_put but see spl above */ 3512 } 3513 /* just for safety */ 3514 LIST_INIT(&tp->t_sc); 3515 3516 splx(s); 3517 } 3518 3519 /* 3520 * Find an entry in the syn cache. 3521 */ 3522 struct syn_cache * 3523 syn_cache_lookup(const struct sockaddr *src, const struct sockaddr *dst, 3524 struct syn_cache_head **headp) 3525 { 3526 struct syn_cache *sc; 3527 struct syn_cache_head *scp; 3528 u_int32_t hash; 3529 int s; 3530 3531 SYN_HASHALL(hash, src, dst); 3532 3533 scp = &tcp_syn_cache[hash % tcp_syn_cache_size]; 3534 *headp = scp; 3535 s = splsoftnet(); 3536 for (sc = TAILQ_FIRST(&scp->sch_bucket); sc != NULL; 3537 sc = TAILQ_NEXT(sc, sc_bucketq)) { 3538 if (sc->sc_hash != hash) 3539 continue; 3540 if (!bcmp(&sc->sc_src, src, src->sa_len) && 3541 !bcmp(&sc->sc_dst, dst, dst->sa_len)) { 3542 splx(s); 3543 return (sc); 3544 } 3545 } 3546 splx(s); 3547 return (NULL); 3548 } 3549 3550 /* 3551 * This function gets called when we receive an ACK for a 3552 * socket in the LISTEN state. We look up the connection 3553 * in the syn cache, and if its there, we pull it out of 3554 * the cache and turn it into a full-blown connection in 3555 * the SYN-RECEIVED state. 3556 * 3557 * The return values may not be immediately obvious, and their effects 3558 * can be subtle, so here they are: 3559 * 3560 * NULL SYN was not found in cache; caller should drop the 3561 * packet and send an RST. 3562 * 3563 * -1 We were unable to create the new connection, and are 3564 * aborting it. An ACK,RST is being sent to the peer 3565 * (unless we got screwey sequence numbners; see below), 3566 * because the 3-way handshake has been completed. Caller 3567 * should not free the mbuf, since we may be using it. If 3568 * we are not, we will free it. 3569 * 3570 * Otherwise, the return value is a pointer to the new socket 3571 * associated with the connection. 3572 */ 3573 struct socket * 3574 syn_cache_get(struct sockaddr *src, struct sockaddr *dst, 3575 struct tcphdr *th, unsigned int hlen, unsigned int tlen, 3576 struct socket *so, struct mbuf *m) 3577 { 3578 struct syn_cache *sc; 3579 struct syn_cache_head *scp; 3580 struct inpcb *inp = NULL; 3581 #ifdef INET6 3582 struct in6pcb *in6p = NULL; 3583 #endif 3584 struct tcpcb *tp = 0; 3585 struct mbuf *am; 3586 int s; 3587 struct socket *oso; 3588 3589 s = splsoftnet(); 3590 if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { 3591 splx(s); 3592 return (NULL); 3593 } 3594 3595 /* 3596 * Verify the sequence and ack numbers. Try getting the correct 3597 * response again. 3598 */ 3599 if ((th->th_ack != sc->sc_iss + 1) || 3600 SEQ_LEQ(th->th_seq, sc->sc_irs) || 3601 SEQ_GT(th->th_seq, sc->sc_irs + 1 + sc->sc_win)) { 3602 (void) syn_cache_respond(sc, m); 3603 splx(s); 3604 return ((struct socket *)(-1)); 3605 } 3606 3607 /* Remove this cache entry */ 3608 syn_cache_rm(sc); 3609 splx(s); 3610 3611 /* 3612 * Ok, create the full blown connection, and set things up 3613 * as they would have been set up if we had created the 3614 * connection when the SYN arrived. If we can't create 3615 * the connection, abort it. 3616 */ 3617 /* 3618 * inp still has the OLD in_pcb stuff, set the 3619 * v6-related flags on the new guy, too. This is 3620 * done particularly for the case where an AF_INET6 3621 * socket is bound only to a port, and a v4 connection 3622 * comes in on that port. 3623 * we also copy the flowinfo from the original pcb 3624 * to the new one. 3625 */ 3626 oso = so; 3627 so = sonewconn(so, SS_ISCONNECTED); 3628 if (so == NULL) 3629 goto resetandabort; 3630 3631 switch (so->so_proto->pr_domain->dom_family) { 3632 #ifdef INET 3633 case AF_INET: 3634 inp = sotoinpcb(so); 3635 break; 3636 #endif 3637 #ifdef INET6 3638 case AF_INET6: 3639 in6p = sotoin6pcb(so); 3640 break; 3641 #endif 3642 } 3643 switch (src->sa_family) { 3644 #ifdef INET 3645 case AF_INET: 3646 if (inp) { 3647 inp->inp_laddr = ((struct sockaddr_in *)dst)->sin_addr; 3648 inp->inp_lport = ((struct sockaddr_in *)dst)->sin_port; 3649 inp->inp_options = ip_srcroute(); 3650 in_pcbstate(inp, INP_BOUND); 3651 if (inp->inp_options == NULL) { 3652 inp->inp_options = sc->sc_ipopts; 3653 sc->sc_ipopts = NULL; 3654 } 3655 } 3656 #ifdef INET6 3657 else if (in6p) { 3658 /* IPv4 packet to AF_INET6 socket */ 3659 bzero(&in6p->in6p_laddr, sizeof(in6p->in6p_laddr)); 3660 in6p->in6p_laddr.s6_addr16[5] = htons(0xffff); 3661 bcopy(&((struct sockaddr_in *)dst)->sin_addr, 3662 &in6p->in6p_laddr.s6_addr32[3], 3663 sizeof(((struct sockaddr_in *)dst)->sin_addr)); 3664 in6p->in6p_lport = ((struct sockaddr_in *)dst)->sin_port; 3665 in6totcpcb(in6p)->t_family = AF_INET; 3666 if (sotoin6pcb(oso)->in6p_flags & IN6P_IPV6_V6ONLY) 3667 in6p->in6p_flags |= IN6P_IPV6_V6ONLY; 3668 else 3669 in6p->in6p_flags &= ~IN6P_IPV6_V6ONLY; 3670 in6_pcbstate(in6p, IN6P_BOUND); 3671 } 3672 #endif 3673 break; 3674 #endif 3675 #ifdef INET6 3676 case AF_INET6: 3677 if (in6p) { 3678 in6p->in6p_laddr = ((struct sockaddr_in6 *)dst)->sin6_addr; 3679 in6p->in6p_lport = ((struct sockaddr_in6 *)dst)->sin6_port; 3680 in6_pcbstate(in6p, IN6P_BOUND); 3681 } 3682 break; 3683 #endif 3684 } 3685 #ifdef INET6 3686 if (in6p && in6totcpcb(in6p)->t_family == AF_INET6 && sotoinpcb(oso)) { 3687 struct in6pcb *oin6p = sotoin6pcb(oso); 3688 /* inherit socket options from the listening socket */ 3689 in6p->in6p_flags |= (oin6p->in6p_flags & IN6P_CONTROLOPTS); 3690 if (in6p->in6p_flags & IN6P_CONTROLOPTS) { 3691 m_freem(in6p->in6p_options); 3692 in6p->in6p_options = 0; 3693 } 3694 ip6_savecontrol(in6p, &in6p->in6p_options, 3695 mtod(m, struct ip6_hdr *), m); 3696 } 3697 #endif 3698 3699 #if defined(IPSEC) || defined(FAST_IPSEC) 3700 /* 3701 * we make a copy of policy, instead of sharing the policy, 3702 * for better behavior in terms of SA lookup and dead SA removal. 3703 */ 3704 if (inp) { 3705 /* copy old policy into new socket's */ 3706 if (ipsec_copy_pcbpolicy(sotoinpcb(oso)->inp_sp, inp->inp_sp)) 3707 printf("tcp_input: could not copy policy\n"); 3708 } 3709 #ifdef INET6 3710 else if (in6p) { 3711 /* copy old policy into new socket's */ 3712 if (ipsec_copy_pcbpolicy(sotoin6pcb(oso)->in6p_sp, 3713 in6p->in6p_sp)) 3714 printf("tcp_input: could not copy policy\n"); 3715 } 3716 #endif 3717 #endif 3718 3719 /* 3720 * Give the new socket our cached route reference. 3721 */ 3722 if (inp) { 3723 rtcache_copy(&inp->inp_route, &sc->sc_route); 3724 rtcache_free(&sc->sc_route); 3725 } 3726 #ifdef INET6 3727 else { 3728 rtcache_copy(&in6p->in6p_route, &sc->sc_route); 3729 rtcache_free(&sc->sc_route); 3730 } 3731 #endif 3732 3733 am = m_get(M_DONTWAIT, MT_SONAME); /* XXX */ 3734 if (am == NULL) 3735 goto resetandabort; 3736 MCLAIM(am, &tcp_mowner); 3737 am->m_len = src->sa_len; 3738 bcopy(src, mtod(am, void *), src->sa_len); 3739 if (inp) { 3740 if (in_pcbconnect(inp, am, &lwp0)) { 3741 (void) m_free(am); 3742 goto resetandabort; 3743 } 3744 } 3745 #ifdef INET6 3746 else if (in6p) { 3747 if (src->sa_family == AF_INET) { 3748 /* IPv4 packet to AF_INET6 socket */ 3749 struct sockaddr_in6 *sin6; 3750 sin6 = mtod(am, struct sockaddr_in6 *); 3751 am->m_len = sizeof(*sin6); 3752 bzero(sin6, sizeof(*sin6)); 3753 sin6->sin6_family = AF_INET6; 3754 sin6->sin6_len = sizeof(*sin6); 3755 sin6->sin6_port = ((struct sockaddr_in *)src)->sin_port; 3756 sin6->sin6_addr.s6_addr16[5] = htons(0xffff); 3757 bcopy(&((struct sockaddr_in *)src)->sin_addr, 3758 &sin6->sin6_addr.s6_addr32[3], 3759 sizeof(sin6->sin6_addr.s6_addr32[3])); 3760 } 3761 if (in6_pcbconnect(in6p, am, NULL)) { 3762 (void) m_free(am); 3763 goto resetandabort; 3764 } 3765 } 3766 #endif 3767 else { 3768 (void) m_free(am); 3769 goto resetandabort; 3770 } 3771 (void) m_free(am); 3772 3773 if (inp) 3774 tp = intotcpcb(inp); 3775 #ifdef INET6 3776 else if (in6p) 3777 tp = in6totcpcb(in6p); 3778 #endif 3779 else 3780 tp = NULL; 3781 tp->t_flags = sototcpcb(oso)->t_flags & TF_NODELAY; 3782 if (sc->sc_request_r_scale != 15) { 3783 tp->requested_s_scale = sc->sc_requested_s_scale; 3784 tp->request_r_scale = sc->sc_request_r_scale; 3785 tp->snd_scale = sc->sc_requested_s_scale; 3786 tp->rcv_scale = sc->sc_request_r_scale; 3787 tp->t_flags |= TF_REQ_SCALE|TF_RCVD_SCALE; 3788 } 3789 if (sc->sc_flags & SCF_TIMESTAMP) 3790 tp->t_flags |= TF_REQ_TSTMP|TF_RCVD_TSTMP; 3791 tp->ts_timebase = sc->sc_timebase; 3792 3793 tp->t_template = tcp_template(tp); 3794 if (tp->t_template == 0) { 3795 tp = tcp_drop(tp, ENOBUFS); /* destroys socket */ 3796 so = NULL; 3797 m_freem(m); 3798 goto abort; 3799 } 3800 3801 tp->iss = sc->sc_iss; 3802 tp->irs = sc->sc_irs; 3803 tcp_sendseqinit(tp); 3804 tcp_rcvseqinit(tp); 3805 tp->t_state = TCPS_SYN_RECEIVED; 3806 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepinit); 3807 tcpstat.tcps_accepts++; 3808 3809 if ((sc->sc_flags & SCF_SACK_PERMIT) && tcp_do_sack) 3810 tp->t_flags |= TF_WILL_SACK; 3811 3812 if ((sc->sc_flags & SCF_ECN_PERMIT) && tcp_do_ecn) 3813 tp->t_flags |= TF_ECN_PERMIT; 3814 3815 #ifdef TCP_SIGNATURE 3816 if (sc->sc_flags & SCF_SIGNATURE) 3817 tp->t_flags |= TF_SIGNATURE; 3818 #endif 3819 3820 /* Initialize tp->t_ourmss before we deal with the peer's! */ 3821 tp->t_ourmss = sc->sc_ourmaxseg; 3822 tcp_mss_from_peer(tp, sc->sc_peermaxseg); 3823 3824 /* 3825 * Initialize the initial congestion window. If we 3826 * had to retransmit the SYN,ACK, we must initialize cwnd 3827 * to 1 segment (i.e. the Loss Window). 3828 */ 3829 if (sc->sc_rxtshift) 3830 tp->snd_cwnd = tp->t_peermss; 3831 else { 3832 int ss = tcp_init_win; 3833 #ifdef INET 3834 if (inp != NULL && in_localaddr(inp->inp_faddr)) 3835 ss = tcp_init_win_local; 3836 #endif 3837 #ifdef INET6 3838 if (in6p != NULL && in6_localaddr(&in6p->in6p_faddr)) 3839 ss = tcp_init_win_local; 3840 #endif 3841 tp->snd_cwnd = TCP_INITIAL_WINDOW(ss, tp->t_peermss); 3842 } 3843 3844 tcp_rmx_rtt(tp); 3845 tp->snd_wl1 = sc->sc_irs; 3846 tp->rcv_up = sc->sc_irs + 1; 3847 3848 /* 3849 * This is what whould have happened in tcp_output() when 3850 * the SYN,ACK was sent. 3851 */ 3852 tp->snd_up = tp->snd_una; 3853 tp->snd_max = tp->snd_nxt = tp->iss+1; 3854 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 3855 if (sc->sc_win > 0 && SEQ_GT(tp->rcv_nxt + sc->sc_win, tp->rcv_adv)) 3856 tp->rcv_adv = tp->rcv_nxt + sc->sc_win; 3857 tp->last_ack_sent = tp->rcv_nxt; 3858 tp->t_partialacks = -1; 3859 tp->t_dupacks = 0; 3860 3861 tcpstat.tcps_sc_completed++; 3862 s = splsoftnet(); 3863 syn_cache_put(sc); 3864 splx(s); 3865 return (so); 3866 3867 resetandabort: 3868 (void)tcp_respond(NULL, m, m, th, (tcp_seq)0, th->th_ack, TH_RST); 3869 abort: 3870 if (so != NULL) 3871 (void) soabort(so); 3872 s = splsoftnet(); 3873 syn_cache_put(sc); 3874 splx(s); 3875 tcpstat.tcps_sc_aborted++; 3876 return ((struct socket *)(-1)); 3877 } 3878 3879 /* 3880 * This function is called when we get a RST for a 3881 * non-existent connection, so that we can see if the 3882 * connection is in the syn cache. If it is, zap it. 3883 */ 3884 3885 void 3886 syn_cache_reset(struct sockaddr *src, struct sockaddr *dst, struct tcphdr *th) 3887 { 3888 struct syn_cache *sc; 3889 struct syn_cache_head *scp; 3890 int s = splsoftnet(); 3891 3892 if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { 3893 splx(s); 3894 return; 3895 } 3896 if (SEQ_LT(th->th_seq, sc->sc_irs) || 3897 SEQ_GT(th->th_seq, sc->sc_irs+1)) { 3898 splx(s); 3899 return; 3900 } 3901 syn_cache_rm(sc); 3902 tcpstat.tcps_sc_reset++; 3903 syn_cache_put(sc); /* calls pool_put but see spl above */ 3904 splx(s); 3905 } 3906 3907 void 3908 syn_cache_unreach(const struct sockaddr *src, const struct sockaddr *dst, 3909 struct tcphdr *th) 3910 { 3911 struct syn_cache *sc; 3912 struct syn_cache_head *scp; 3913 int s; 3914 3915 s = splsoftnet(); 3916 if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { 3917 splx(s); 3918 return; 3919 } 3920 /* If the sequence number != sc_iss, then it's a bogus ICMP msg */ 3921 if (ntohl (th->th_seq) != sc->sc_iss) { 3922 splx(s); 3923 return; 3924 } 3925 3926 /* 3927 * If we've retransmitted 3 times and this is our second error, 3928 * we remove the entry. Otherwise, we allow it to continue on. 3929 * This prevents us from incorrectly nuking an entry during a 3930 * spurious network outage. 3931 * 3932 * See tcp_notify(). 3933 */ 3934 if ((sc->sc_flags & SCF_UNREACH) == 0 || sc->sc_rxtshift < 3) { 3935 sc->sc_flags |= SCF_UNREACH; 3936 splx(s); 3937 return; 3938 } 3939 3940 syn_cache_rm(sc); 3941 tcpstat.tcps_sc_unreach++; 3942 syn_cache_put(sc); /* calls pool_put but see spl above */ 3943 splx(s); 3944 } 3945 3946 /* 3947 * Given a LISTEN socket and an inbound SYN request, add 3948 * this to the syn cache, and send back a segment: 3949 * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK> 3950 * to the source. 3951 * 3952 * IMPORTANT NOTE: We do _NOT_ ACK data that might accompany the SYN. 3953 * Doing so would require that we hold onto the data and deliver it 3954 * to the application. However, if we are the target of a SYN-flood 3955 * DoS attack, an attacker could send data which would eventually 3956 * consume all available buffer space if it were ACKed. By not ACKing 3957 * the data, we avoid this DoS scenario. 3958 */ 3959 3960 int 3961 syn_cache_add(struct sockaddr *src, struct sockaddr *dst, struct tcphdr *th, 3962 unsigned int hlen, struct socket *so, struct mbuf *m, u_char *optp, 3963 int optlen, struct tcp_opt_info *oi) 3964 { 3965 struct tcpcb tb, *tp; 3966 long win; 3967 struct syn_cache *sc; 3968 struct syn_cache_head *scp; 3969 struct mbuf *ipopts; 3970 struct tcp_opt_info opti; 3971 int s; 3972 3973 tp = sototcpcb(so); 3974 3975 bzero(&opti, sizeof(opti)); 3976 3977 /* 3978 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN 3979 * 3980 * Note this check is performed in tcp_input() very early on. 3981 */ 3982 3983 /* 3984 * Initialize some local state. 3985 */ 3986 win = sbspace(&so->so_rcv); 3987 if (win > TCP_MAXWIN) 3988 win = TCP_MAXWIN; 3989 3990 switch (src->sa_family) { 3991 #ifdef INET 3992 case AF_INET: 3993 /* 3994 * Remember the IP options, if any. 3995 */ 3996 ipopts = ip_srcroute(); 3997 break; 3998 #endif 3999 default: 4000 ipopts = NULL; 4001 } 4002 4003 #ifdef TCP_SIGNATURE 4004 if (optp || (tp->t_flags & TF_SIGNATURE)) 4005 #else 4006 if (optp) 4007 #endif 4008 { 4009 tb.t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; 4010 #ifdef TCP_SIGNATURE 4011 tb.t_flags |= (tp->t_flags & TF_SIGNATURE); 4012 #endif 4013 tb.t_state = TCPS_LISTEN; 4014 if (tcp_dooptions(&tb, optp, optlen, th, m, m->m_pkthdr.len - 4015 sizeof(struct tcphdr) - optlen - hlen, oi) < 0) 4016 return (0); 4017 } else 4018 tb.t_flags = 0; 4019 4020 /* 4021 * See if we already have an entry for this connection. 4022 * If we do, resend the SYN,ACK. We do not count this 4023 * as a retransmission (XXX though maybe we should). 4024 */ 4025 if ((sc = syn_cache_lookup(src, dst, &scp)) != NULL) { 4026 tcpstat.tcps_sc_dupesyn++; 4027 if (ipopts) { 4028 /* 4029 * If we were remembering a previous source route, 4030 * forget it and use the new one we've been given. 4031 */ 4032 if (sc->sc_ipopts) 4033 (void) m_free(sc->sc_ipopts); 4034 sc->sc_ipopts = ipopts; 4035 } 4036 sc->sc_timestamp = tb.ts_recent; 4037 if (syn_cache_respond(sc, m) == 0) { 4038 tcpstat.tcps_sndacks++; 4039 tcpstat.tcps_sndtotal++; 4040 } 4041 return (1); 4042 } 4043 4044 s = splsoftnet(); 4045 sc = pool_get(&syn_cache_pool, PR_NOWAIT); 4046 splx(s); 4047 if (sc == NULL) { 4048 if (ipopts) 4049 (void) m_free(ipopts); 4050 return (0); 4051 } 4052 4053 /* 4054 * Fill in the cache, and put the necessary IP and TCP 4055 * options into the reply. 4056 */ 4057 bzero(sc, sizeof(struct syn_cache)); 4058 callout_init(&sc->sc_timer, 0); 4059 bcopy(src, &sc->sc_src, src->sa_len); 4060 bcopy(dst, &sc->sc_dst, dst->sa_len); 4061 sc->sc_flags = 0; 4062 sc->sc_ipopts = ipopts; 4063 sc->sc_irs = th->th_seq; 4064 switch (src->sa_family) { 4065 #ifdef INET 4066 case AF_INET: 4067 { 4068 struct sockaddr_in *srcin = (void *) src; 4069 struct sockaddr_in *dstin = (void *) dst; 4070 4071 sc->sc_iss = tcp_new_iss1(&dstin->sin_addr, 4072 &srcin->sin_addr, dstin->sin_port, 4073 srcin->sin_port, sizeof(dstin->sin_addr), 0); 4074 break; 4075 } 4076 #endif /* INET */ 4077 #ifdef INET6 4078 case AF_INET6: 4079 { 4080 struct sockaddr_in6 *srcin6 = (void *) src; 4081 struct sockaddr_in6 *dstin6 = (void *) dst; 4082 4083 sc->sc_iss = tcp_new_iss1(&dstin6->sin6_addr, 4084 &srcin6->sin6_addr, dstin6->sin6_port, 4085 srcin6->sin6_port, sizeof(dstin6->sin6_addr), 0); 4086 break; 4087 } 4088 #endif /* INET6 */ 4089 } 4090 sc->sc_peermaxseg = oi->maxseg; 4091 sc->sc_ourmaxseg = tcp_mss_to_advertise(m->m_flags & M_PKTHDR ? 4092 m->m_pkthdr.rcvif : NULL, 4093 sc->sc_src.sa.sa_family); 4094 sc->sc_win = win; 4095 sc->sc_timebase = tcp_now - 1; /* see tcp_newtcpcb() */ 4096 sc->sc_timestamp = tb.ts_recent; 4097 if ((tb.t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP)) == 4098 (TF_REQ_TSTMP|TF_RCVD_TSTMP)) 4099 sc->sc_flags |= SCF_TIMESTAMP; 4100 if ((tb.t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == 4101 (TF_RCVD_SCALE|TF_REQ_SCALE)) { 4102 sc->sc_requested_s_scale = tb.requested_s_scale; 4103 sc->sc_request_r_scale = 0; 4104 /* 4105 * Pick the smallest possible scaling factor that 4106 * will still allow us to scale up to sb_max. 4107 * 4108 * We do this because there are broken firewalls that 4109 * will corrupt the window scale option, leading to 4110 * the other endpoint believing that our advertised 4111 * window is unscaled. At scale factors larger than 4112 * 5 the unscaled window will drop below 1500 bytes, 4113 * leading to serious problems when traversing these 4114 * broken firewalls. 4115 * 4116 * With the default sbmax of 256K, a scale factor 4117 * of 3 will be chosen by this algorithm. Those who 4118 * choose a larger sbmax should watch out 4119 * for the compatiblity problems mentioned above. 4120 * 4121 * RFC1323: The Window field in a SYN (i.e., a <SYN> 4122 * or <SYN,ACK>) segment itself is never scaled. 4123 */ 4124 while (sc->sc_request_r_scale < TCP_MAX_WINSHIFT && 4125 (TCP_MAXWIN << sc->sc_request_r_scale) < sb_max) 4126 sc->sc_request_r_scale++; 4127 } else { 4128 sc->sc_requested_s_scale = 15; 4129 sc->sc_request_r_scale = 15; 4130 } 4131 if ((tb.t_flags & TF_SACK_PERMIT) && tcp_do_sack) 4132 sc->sc_flags |= SCF_SACK_PERMIT; 4133 4134 /* 4135 * ECN setup packet recieved. 4136 */ 4137 if ((th->th_flags & (TH_ECE|TH_CWR)) && tcp_do_ecn) 4138 sc->sc_flags |= SCF_ECN_PERMIT; 4139 4140 #ifdef TCP_SIGNATURE 4141 if (tb.t_flags & TF_SIGNATURE) 4142 sc->sc_flags |= SCF_SIGNATURE; 4143 #endif 4144 sc->sc_tp = tp; 4145 if (syn_cache_respond(sc, m) == 0) { 4146 syn_cache_insert(sc, tp); 4147 tcpstat.tcps_sndacks++; 4148 tcpstat.tcps_sndtotal++; 4149 } else { 4150 s = splsoftnet(); 4151 syn_cache_put(sc); 4152 splx(s); 4153 tcpstat.tcps_sc_dropped++; 4154 } 4155 return (1); 4156 } 4157 4158 int 4159 syn_cache_respond(struct syn_cache *sc, struct mbuf *m) 4160 { 4161 #ifdef INET6 4162 struct rtentry *rt; 4163 #endif 4164 struct route *ro; 4165 u_int8_t *optp; 4166 int optlen, error; 4167 u_int16_t tlen; 4168 struct ip *ip = NULL; 4169 #ifdef INET6 4170 struct ip6_hdr *ip6 = NULL; 4171 #endif 4172 struct tcpcb *tp = NULL; 4173 struct tcphdr *th; 4174 u_int hlen; 4175 struct socket *so; 4176 4177 ro = &sc->sc_route; 4178 switch (sc->sc_src.sa.sa_family) { 4179 case AF_INET: 4180 hlen = sizeof(struct ip); 4181 break; 4182 #ifdef INET6 4183 case AF_INET6: 4184 hlen = sizeof(struct ip6_hdr); 4185 break; 4186 #endif 4187 default: 4188 if (m) 4189 m_freem(m); 4190 return (EAFNOSUPPORT); 4191 } 4192 4193 /* Compute the size of the TCP options. */ 4194 optlen = 4 + (sc->sc_request_r_scale != 15 ? 4 : 0) + 4195 ((sc->sc_flags & SCF_SACK_PERMIT) ? (TCPOLEN_SACK_PERMITTED + 2) : 0) + 4196 #ifdef TCP_SIGNATURE 4197 ((sc->sc_flags & SCF_SIGNATURE) ? (TCPOLEN_SIGNATURE + 2) : 0) + 4198 #endif 4199 ((sc->sc_flags & SCF_TIMESTAMP) ? TCPOLEN_TSTAMP_APPA : 0); 4200 4201 tlen = hlen + sizeof(struct tcphdr) + optlen; 4202 4203 /* 4204 * Create the IP+TCP header from scratch. 4205 */ 4206 if (m) 4207 m_freem(m); 4208 #ifdef DIAGNOSTIC 4209 if (max_linkhdr + tlen > MCLBYTES) 4210 return (ENOBUFS); 4211 #endif 4212 MGETHDR(m, M_DONTWAIT, MT_DATA); 4213 if (m && tlen > MHLEN) { 4214 MCLGET(m, M_DONTWAIT); 4215 if ((m->m_flags & M_EXT) == 0) { 4216 m_freem(m); 4217 m = NULL; 4218 } 4219 } 4220 if (m == NULL) 4221 return (ENOBUFS); 4222 MCLAIM(m, &tcp_tx_mowner); 4223 4224 /* Fixup the mbuf. */ 4225 m->m_data += max_linkhdr; 4226 m->m_len = m->m_pkthdr.len = tlen; 4227 if (sc->sc_tp) { 4228 tp = sc->sc_tp; 4229 if (tp->t_inpcb) 4230 so = tp->t_inpcb->inp_socket; 4231 #ifdef INET6 4232 else if (tp->t_in6pcb) 4233 so = tp->t_in6pcb->in6p_socket; 4234 #endif 4235 else 4236 so = NULL; 4237 } else 4238 so = NULL; 4239 m->m_pkthdr.rcvif = NULL; 4240 memset(mtod(m, u_char *), 0, tlen); 4241 4242 switch (sc->sc_src.sa.sa_family) { 4243 case AF_INET: 4244 ip = mtod(m, struct ip *); 4245 ip->ip_v = 4; 4246 ip->ip_dst = sc->sc_src.sin.sin_addr; 4247 ip->ip_src = sc->sc_dst.sin.sin_addr; 4248 ip->ip_p = IPPROTO_TCP; 4249 th = (struct tcphdr *)(ip + 1); 4250 th->th_dport = sc->sc_src.sin.sin_port; 4251 th->th_sport = sc->sc_dst.sin.sin_port; 4252 break; 4253 #ifdef INET6 4254 case AF_INET6: 4255 ip6 = mtod(m, struct ip6_hdr *); 4256 ip6->ip6_vfc = IPV6_VERSION; 4257 ip6->ip6_dst = sc->sc_src.sin6.sin6_addr; 4258 ip6->ip6_src = sc->sc_dst.sin6.sin6_addr; 4259 ip6->ip6_nxt = IPPROTO_TCP; 4260 /* ip6_plen will be updated in ip6_output() */ 4261 th = (struct tcphdr *)(ip6 + 1); 4262 th->th_dport = sc->sc_src.sin6.sin6_port; 4263 th->th_sport = sc->sc_dst.sin6.sin6_port; 4264 break; 4265 #endif 4266 default: 4267 th = NULL; 4268 } 4269 4270 th->th_seq = htonl(sc->sc_iss); 4271 th->th_ack = htonl(sc->sc_irs + 1); 4272 th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; 4273 th->th_flags = TH_SYN|TH_ACK; 4274 th->th_win = htons(sc->sc_win); 4275 /* th_sum already 0 */ 4276 /* th_urp already 0 */ 4277 4278 /* Tack on the TCP options. */ 4279 optp = (u_int8_t *)(th + 1); 4280 *optp++ = TCPOPT_MAXSEG; 4281 *optp++ = 4; 4282 *optp++ = (sc->sc_ourmaxseg >> 8) & 0xff; 4283 *optp++ = sc->sc_ourmaxseg & 0xff; 4284 4285 if (sc->sc_request_r_scale != 15) { 4286 *((u_int32_t *)optp) = htonl(TCPOPT_NOP << 24 | 4287 TCPOPT_WINDOW << 16 | TCPOLEN_WINDOW << 8 | 4288 sc->sc_request_r_scale); 4289 optp += 4; 4290 } 4291 4292 if (sc->sc_flags & SCF_TIMESTAMP) { 4293 u_int32_t *lp = (u_int32_t *)(optp); 4294 /* Form timestamp option as shown in appendix A of RFC 1323. */ 4295 *lp++ = htonl(TCPOPT_TSTAMP_HDR); 4296 *lp++ = htonl(SYN_CACHE_TIMESTAMP(sc)); 4297 *lp = htonl(sc->sc_timestamp); 4298 optp += TCPOLEN_TSTAMP_APPA; 4299 } 4300 4301 if (sc->sc_flags & SCF_SACK_PERMIT) { 4302 u_int8_t *p = optp; 4303 4304 /* Let the peer know that we will SACK. */ 4305 p[0] = TCPOPT_SACK_PERMITTED; 4306 p[1] = 2; 4307 p[2] = TCPOPT_NOP; 4308 p[3] = TCPOPT_NOP; 4309 optp += 4; 4310 } 4311 4312 /* 4313 * Send ECN SYN-ACK setup packet. 4314 * Routes can be asymetric, so, even if we receive a packet 4315 * with ECE and CWR set, we must not assume no one will block 4316 * the ECE packet we are about to send. 4317 */ 4318 if ((sc->sc_flags & SCF_ECN_PERMIT) && tp && 4319 SEQ_GEQ(tp->snd_nxt, tp->snd_max)) { 4320 th->th_flags |= TH_ECE; 4321 tcpstat.tcps_ecn_shs++; 4322 4323 /* 4324 * draft-ietf-tcpm-ecnsyn-00.txt 4325 * 4326 * "[...] a TCP node MAY respond to an ECN-setup 4327 * SYN packet by setting ECT in the responding 4328 * ECN-setup SYN/ACK packet, indicating to routers 4329 * that the SYN/ACK packet is ECN-Capable. 4330 * This allows a congested router along the path 4331 * to mark the packet instead of dropping the 4332 * packet as an indication of congestion." 4333 * 4334 * "[...] There can be a great benefit in setting 4335 * an ECN-capable codepoint in SYN/ACK packets [...] 4336 * Congestion is most likely to occur in 4337 * the server-to-client direction. As a result, 4338 * setting an ECN-capable codepoint in SYN/ACK 4339 * packets can reduce the occurence of three-second 4340 * retransmit timeouts resulting from the drop 4341 * of SYN/ACK packets." 4342 * 4343 * Page 4 and 6, January 2006. 4344 */ 4345 4346 switch (sc->sc_src.sa.sa_family) { 4347 #ifdef INET 4348 case AF_INET: 4349 ip->ip_tos |= IPTOS_ECN_ECT0; 4350 break; 4351 #endif 4352 #ifdef INET6 4353 case AF_INET6: 4354 ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20); 4355 break; 4356 #endif 4357 } 4358 tcpstat.tcps_ecn_ect++; 4359 } 4360 4361 #ifdef TCP_SIGNATURE 4362 if (sc->sc_flags & SCF_SIGNATURE) { 4363 struct secasvar *sav; 4364 u_int8_t *sigp; 4365 4366 sav = tcp_signature_getsav(m, th); 4367 4368 if (sav == NULL) { 4369 if (m) 4370 m_freem(m); 4371 return (EPERM); 4372 } 4373 4374 *optp++ = TCPOPT_SIGNATURE; 4375 *optp++ = TCPOLEN_SIGNATURE; 4376 sigp = optp; 4377 bzero(optp, TCP_SIGLEN); 4378 optp += TCP_SIGLEN; 4379 *optp++ = TCPOPT_NOP; 4380 *optp++ = TCPOPT_EOL; 4381 4382 (void)tcp_signature(m, th, hlen, sav, sigp); 4383 4384 key_sa_recordxfer(sav, m); 4385 #ifdef FAST_IPSEC 4386 KEY_FREESAV(&sav); 4387 #else 4388 key_freesav(sav); 4389 #endif 4390 } 4391 #endif 4392 4393 /* Compute the packet's checksum. */ 4394 switch (sc->sc_src.sa.sa_family) { 4395 case AF_INET: 4396 ip->ip_len = htons(tlen - hlen); 4397 th->th_sum = 0; 4398 th->th_sum = in4_cksum(m, IPPROTO_TCP, hlen, tlen - hlen); 4399 break; 4400 #ifdef INET6 4401 case AF_INET6: 4402 ip6->ip6_plen = htons(tlen - hlen); 4403 th->th_sum = 0; 4404 th->th_sum = in6_cksum(m, IPPROTO_TCP, hlen, tlen - hlen); 4405 break; 4406 #endif 4407 } 4408 4409 /* 4410 * Fill in some straggling IP bits. Note the stack expects 4411 * ip_len to be in host order, for convenience. 4412 */ 4413 switch (sc->sc_src.sa.sa_family) { 4414 #ifdef INET 4415 case AF_INET: 4416 ip->ip_len = htons(tlen); 4417 ip->ip_ttl = ip_defttl; 4418 /* XXX tos? */ 4419 break; 4420 #endif 4421 #ifdef INET6 4422 case AF_INET6: 4423 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 4424 ip6->ip6_vfc |= IPV6_VERSION; 4425 ip6->ip6_plen = htons(tlen - hlen); 4426 /* ip6_hlim will be initialized afterwards */ 4427 /* XXX flowlabel? */ 4428 break; 4429 #endif 4430 } 4431 4432 /* XXX use IPsec policy on listening socket, on SYN ACK */ 4433 tp = sc->sc_tp; 4434 4435 switch (sc->sc_src.sa.sa_family) { 4436 #ifdef INET 4437 case AF_INET: 4438 error = ip_output(m, sc->sc_ipopts, ro, 4439 (ip_mtudisc ? IP_MTUDISC : 0), 4440 (struct ip_moptions *)NULL, so); 4441 break; 4442 #endif 4443 #ifdef INET6 4444 case AF_INET6: 4445 ip6->ip6_hlim = in6_selecthlim(NULL, 4446 (rt = rtcache_validate(ro)) != NULL ? rt->rt_ifp 4447 : NULL); 4448 4449 error = ip6_output(m, NULL /*XXX*/, ro, 0, NULL, so, NULL); 4450 break; 4451 #endif 4452 default: 4453 error = EAFNOSUPPORT; 4454 break; 4455 } 4456 return (error); 4457 } 4458