tcp_input.c revision 1.250
1 /* $NetBSD: tcp_input.c,v 1.250 2006/10/12 11:46:30 rpaulo 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 1.250 2006/10/12 11:46:30 rpaulo 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 177 178 #include <net/if.h> 179 #include <net/route.h> 180 #include <net/if_types.h> 181 182 #include <netinet/in.h> 183 #include <netinet/in_systm.h> 184 #include <netinet/ip.h> 185 #include <netinet/in_pcb.h> 186 #include <netinet/in_var.h> 187 #include <netinet/ip_var.h> 188 #include <netinet/in_offload.h> 189 190 #ifdef INET6 191 #ifndef INET 192 #include <netinet/in.h> 193 #endif 194 #include <netinet/ip6.h> 195 #include <netinet6/ip6_var.h> 196 #include <netinet6/in6_pcb.h> 197 #include <netinet6/ip6_var.h> 198 #include <netinet6/in6_var.h> 199 #include <netinet/icmp6.h> 200 #include <netinet6/nd6.h> 201 #ifdef TCP_SIGNATURE 202 #include <netinet6/scope6_var.h> 203 #endif 204 #endif 205 206 #ifndef INET6 207 /* always need ip6.h for IP6_EXTHDR_GET */ 208 #include <netinet/ip6.h> 209 #endif 210 211 #include <netinet/tcp.h> 212 #include <netinet/tcp_fsm.h> 213 #include <netinet/tcp_seq.h> 214 #include <netinet/tcp_timer.h> 215 #include <netinet/tcp_var.h> 216 #include <netinet/tcpip.h> 217 #include <netinet/tcp_congctl.h> 218 #include <netinet/tcp_debug.h> 219 220 #include <machine/stdarg.h> 221 222 #ifdef IPSEC 223 #include <netinet6/ipsec.h> 224 #include <netkey/key.h> 225 #endif /*IPSEC*/ 226 #ifdef INET6 227 #include "faith.h" 228 #if defined(NFAITH) && NFAITH > 0 229 #include <net/if_faith.h> 230 #endif 231 #endif /* IPSEC */ 232 233 #ifdef FAST_IPSEC 234 #include <netipsec/ipsec.h> 235 #include <netipsec/ipsec_var.h> /* XXX ipsecstat namespace */ 236 #include <netipsec/key.h> 237 #ifdef INET6 238 #include <netipsec/ipsec6.h> 239 #endif 240 #endif /* FAST_IPSEC*/ 241 242 int tcprexmtthresh = 3; 243 int tcp_log_refused; 244 245 static int tcp_rst_ppslim_count = 0; 246 static struct timeval tcp_rst_ppslim_last; 247 static int tcp_ackdrop_ppslim_count = 0; 248 static struct timeval tcp_ackdrop_ppslim_last; 249 250 #define TCP_PAWS_IDLE (24U * 24 * 60 * 60 * PR_SLOWHZ) 251 252 /* for modulo comparisons of timestamps */ 253 #define TSTMP_LT(a,b) ((int)((a)-(b)) < 0) 254 #define TSTMP_GEQ(a,b) ((int)((a)-(b)) >= 0) 255 256 /* 257 * Neighbor Discovery, Neighbor Unreachability Detection Upper layer hint. 258 */ 259 #ifdef INET6 260 #define ND6_HINT(tp) \ 261 do { \ 262 if (tp && tp->t_in6pcb && tp->t_family == AF_INET6 && \ 263 tp->t_in6pcb->in6p_route.ro_rt) { \ 264 nd6_nud_hint(tp->t_in6pcb->in6p_route.ro_rt, NULL, 0); \ 265 } \ 266 } while (/*CONSTCOND*/ 0) 267 #else 268 #define ND6_HINT(tp) 269 #endif 270 271 /* 272 * Macro to compute ACK transmission behavior. Delay the ACK unless 273 * we have already delayed an ACK (must send an ACK every two segments). 274 * We also ACK immediately if we received a PUSH and the ACK-on-PUSH 275 * option is enabled. 276 */ 277 #define TCP_SETUP_ACK(tp, th) \ 278 do { \ 279 if ((tp)->t_flags & TF_DELACK || \ 280 (tcp_ack_on_push && (th)->th_flags & TH_PUSH)) \ 281 tp->t_flags |= TF_ACKNOW; \ 282 else \ 283 TCP_SET_DELACK(tp); \ 284 } while (/*CONSTCOND*/ 0) 285 286 #define ICMP_CHECK(tp, th, acked) \ 287 do { \ 288 /* \ 289 * If we had a pending ICMP message that \ 290 * refers to data that have just been \ 291 * acknowledged, disregard the recorded ICMP \ 292 * message. \ 293 */ \ 294 if (((tp)->t_flags & TF_PMTUD_PEND) && \ 295 SEQ_GT((th)->th_ack, (tp)->t_pmtud_th_seq)) \ 296 (tp)->t_flags &= ~TF_PMTUD_PEND; \ 297 \ 298 /* \ 299 * Keep track of the largest chunk of data \ 300 * acknowledged since last PMTU update \ 301 */ \ 302 if ((tp)->t_pmtud_mss_acked < (acked)) \ 303 (tp)->t_pmtud_mss_acked = (acked); \ 304 } while (/*CONSTCOND*/ 0) 305 306 /* 307 * Convert TCP protocol fields to host order for easier processing. 308 */ 309 #define TCP_FIELDS_TO_HOST(th) \ 310 do { \ 311 NTOHL((th)->th_seq); \ 312 NTOHL((th)->th_ack); \ 313 NTOHS((th)->th_win); \ 314 NTOHS((th)->th_urp); \ 315 } while (/*CONSTCOND*/ 0) 316 317 /* 318 * ... and reverse the above. 319 */ 320 #define TCP_FIELDS_TO_NET(th) \ 321 do { \ 322 HTONL((th)->th_seq); \ 323 HTONL((th)->th_ack); \ 324 HTONS((th)->th_win); \ 325 HTONS((th)->th_urp); \ 326 } while (/*CONSTCOND*/ 0) 327 328 #ifdef TCP_CSUM_COUNTERS 329 #include <sys/device.h> 330 331 #if defined(INET) 332 extern struct evcnt tcp_hwcsum_ok; 333 extern struct evcnt tcp_hwcsum_bad; 334 extern struct evcnt tcp_hwcsum_data; 335 extern struct evcnt tcp_swcsum; 336 #endif /* defined(INET) */ 337 #if defined(INET6) 338 extern struct evcnt tcp6_hwcsum_ok; 339 extern struct evcnt tcp6_hwcsum_bad; 340 extern struct evcnt tcp6_hwcsum_data; 341 extern struct evcnt tcp6_swcsum; 342 #endif /* defined(INET6) */ 343 344 #define TCP_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 345 346 #else 347 348 #define TCP_CSUM_COUNTER_INCR(ev) /* nothing */ 349 350 #endif /* TCP_CSUM_COUNTERS */ 351 352 #ifdef TCP_REASS_COUNTERS 353 #include <sys/device.h> 354 355 extern struct evcnt tcp_reass_; 356 extern struct evcnt tcp_reass_empty; 357 extern struct evcnt tcp_reass_iteration[8]; 358 extern struct evcnt tcp_reass_prependfirst; 359 extern struct evcnt tcp_reass_prepend; 360 extern struct evcnt tcp_reass_insert; 361 extern struct evcnt tcp_reass_inserttail; 362 extern struct evcnt tcp_reass_append; 363 extern struct evcnt tcp_reass_appendtail; 364 extern struct evcnt tcp_reass_overlaptail; 365 extern struct evcnt tcp_reass_overlapfront; 366 extern struct evcnt tcp_reass_segdup; 367 extern struct evcnt tcp_reass_fragdup; 368 369 #define TCP_REASS_COUNTER_INCR(ev) (ev)->ev_count++ 370 371 #else 372 373 #define TCP_REASS_COUNTER_INCR(ev) /* nothing */ 374 375 #endif /* TCP_REASS_COUNTERS */ 376 377 #ifdef INET 378 static void tcp4_log_refused(const struct ip *, const struct tcphdr *); 379 #endif 380 #ifdef INET6 381 static void tcp6_log_refused(const struct ip6_hdr *, const struct tcphdr *); 382 #endif 383 384 #define TRAVERSE(x) while ((x)->m_next) (x) = (x)->m_next 385 386 POOL_INIT(tcpipqent_pool, sizeof(struct ipqent), 0, 0, 0, "tcpipqepl", NULL); 387 388 struct ipqent * 389 tcpipqent_alloc() 390 { 391 struct ipqent *ipqe; 392 int s; 393 394 s = splvm(); 395 ipqe = pool_get(&tcpipqent_pool, PR_NOWAIT); 396 splx(s); 397 398 return ipqe; 399 } 400 401 void 402 tcpipqent_free(struct ipqent *ipqe) 403 { 404 int s; 405 406 s = splvm(); 407 pool_put(&tcpipqent_pool, ipqe); 408 splx(s); 409 } 410 411 int 412 tcp_reass(struct tcpcb *tp, struct tcphdr *th, struct mbuf *m, int *tlen) 413 { 414 struct ipqent *p, *q, *nq, *tiqe = NULL; 415 struct socket *so = NULL; 416 int pkt_flags; 417 tcp_seq pkt_seq; 418 unsigned pkt_len; 419 u_long rcvpartdupbyte = 0; 420 u_long rcvoobyte; 421 #ifdef TCP_REASS_COUNTERS 422 u_int count = 0; 423 #endif 424 425 if (tp->t_inpcb) 426 so = tp->t_inpcb->inp_socket; 427 #ifdef INET6 428 else if (tp->t_in6pcb) 429 so = tp->t_in6pcb->in6p_socket; 430 #endif 431 432 TCP_REASS_LOCK_CHECK(tp); 433 434 /* 435 * Call with th==0 after become established to 436 * force pre-ESTABLISHED data up to user socket. 437 */ 438 if (th == 0) 439 goto present; 440 441 rcvoobyte = *tlen; 442 /* 443 * Copy these to local variables because the tcpiphdr 444 * gets munged while we are collapsing mbufs. 445 */ 446 pkt_seq = th->th_seq; 447 pkt_len = *tlen; 448 pkt_flags = th->th_flags; 449 450 TCP_REASS_COUNTER_INCR(&tcp_reass_); 451 452 if ((p = TAILQ_LAST(&tp->segq, ipqehead)) != NULL) { 453 /* 454 * When we miss a packet, the vast majority of time we get 455 * packets that follow it in order. So optimize for that. 456 */ 457 if (pkt_seq == p->ipqe_seq + p->ipqe_len) { 458 p->ipqe_len += pkt_len; 459 p->ipqe_flags |= pkt_flags; 460 m_cat(p->ipre_mlast, m); 461 TRAVERSE(p->ipre_mlast); 462 m = NULL; 463 tiqe = p; 464 TAILQ_REMOVE(&tp->timeq, p, ipqe_timeq); 465 TCP_REASS_COUNTER_INCR(&tcp_reass_appendtail); 466 goto skip_replacement; 467 } 468 /* 469 * While we're here, if the pkt is completely beyond 470 * anything we have, just insert it at the tail. 471 */ 472 if (SEQ_GT(pkt_seq, p->ipqe_seq + p->ipqe_len)) { 473 TCP_REASS_COUNTER_INCR(&tcp_reass_inserttail); 474 goto insert_it; 475 } 476 } 477 478 q = TAILQ_FIRST(&tp->segq); 479 480 if (q != NULL) { 481 /* 482 * If this segment immediately precedes the first out-of-order 483 * block, simply slap the segment in front of it and (mostly) 484 * skip the complicated logic. 485 */ 486 if (pkt_seq + pkt_len == q->ipqe_seq) { 487 q->ipqe_seq = pkt_seq; 488 q->ipqe_len += pkt_len; 489 q->ipqe_flags |= pkt_flags; 490 m_cat(m, q->ipqe_m); 491 q->ipqe_m = m; 492 q->ipre_mlast = m; /* last mbuf may have changed */ 493 TRAVERSE(q->ipre_mlast); 494 tiqe = q; 495 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 496 TCP_REASS_COUNTER_INCR(&tcp_reass_prependfirst); 497 goto skip_replacement; 498 } 499 } else { 500 TCP_REASS_COUNTER_INCR(&tcp_reass_empty); 501 } 502 503 /* 504 * Find a segment which begins after this one does. 505 */ 506 for (p = NULL; q != NULL; q = nq) { 507 nq = TAILQ_NEXT(q, ipqe_q); 508 #ifdef TCP_REASS_COUNTERS 509 count++; 510 #endif 511 /* 512 * If the received segment is just right after this 513 * fragment, merge the two together and then check 514 * for further overlaps. 515 */ 516 if (q->ipqe_seq + q->ipqe_len == pkt_seq) { 517 #ifdef TCPREASS_DEBUG 518 printf("tcp_reass[%p]: concat %u:%u(%u) to %u:%u(%u)\n", 519 tp, pkt_seq, pkt_seq + pkt_len, pkt_len, 520 q->ipqe_seq, q->ipqe_seq + q->ipqe_len, q->ipqe_len); 521 #endif 522 pkt_len += q->ipqe_len; 523 pkt_flags |= q->ipqe_flags; 524 pkt_seq = q->ipqe_seq; 525 m_cat(q->ipre_mlast, m); 526 TRAVERSE(q->ipre_mlast); 527 m = q->ipqe_m; 528 TCP_REASS_COUNTER_INCR(&tcp_reass_append); 529 goto free_ipqe; 530 } 531 /* 532 * If the received segment is completely past this 533 * fragment, we need to go the next fragment. 534 */ 535 if (SEQ_LT(q->ipqe_seq + q->ipqe_len, pkt_seq)) { 536 p = q; 537 continue; 538 } 539 /* 540 * If the fragment is past the received segment, 541 * it (or any following) can't be concatenated. 542 */ 543 if (SEQ_GT(q->ipqe_seq, pkt_seq + pkt_len)) { 544 TCP_REASS_COUNTER_INCR(&tcp_reass_insert); 545 break; 546 } 547 548 /* 549 * We've received all the data in this segment before. 550 * mark it as a duplicate and return. 551 */ 552 if (SEQ_LEQ(q->ipqe_seq, pkt_seq) && 553 SEQ_GEQ(q->ipqe_seq + q->ipqe_len, pkt_seq + pkt_len)) { 554 tcpstat.tcps_rcvduppack++; 555 tcpstat.tcps_rcvdupbyte += pkt_len; 556 tcp_new_dsack(tp, pkt_seq, pkt_len); 557 m_freem(m); 558 if (tiqe != NULL) { 559 tcpipqent_free(tiqe); 560 } 561 TCP_REASS_COUNTER_INCR(&tcp_reass_segdup); 562 return (0); 563 } 564 /* 565 * Received segment completely overlaps this fragment 566 * so we drop the fragment (this keeps the temporal 567 * ordering of segments correct). 568 */ 569 if (SEQ_GEQ(q->ipqe_seq, pkt_seq) && 570 SEQ_LEQ(q->ipqe_seq + q->ipqe_len, pkt_seq + pkt_len)) { 571 rcvpartdupbyte += q->ipqe_len; 572 m_freem(q->ipqe_m); 573 TCP_REASS_COUNTER_INCR(&tcp_reass_fragdup); 574 goto free_ipqe; 575 } 576 /* 577 * RX'ed segment extends past the end of the 578 * fragment. Drop the overlapping bytes. Then 579 * merge the fragment and segment then treat as 580 * a longer received packet. 581 */ 582 if (SEQ_LT(q->ipqe_seq, pkt_seq) && 583 SEQ_GT(q->ipqe_seq + q->ipqe_len, pkt_seq)) { 584 int overlap = q->ipqe_seq + q->ipqe_len - pkt_seq; 585 #ifdef TCPREASS_DEBUG 586 printf("tcp_reass[%p]: trim starting %d bytes of %u:%u(%u)\n", 587 tp, overlap, 588 pkt_seq, pkt_seq + pkt_len, pkt_len); 589 #endif 590 m_adj(m, overlap); 591 rcvpartdupbyte += overlap; 592 m_cat(q->ipre_mlast, m); 593 TRAVERSE(q->ipre_mlast); 594 m = q->ipqe_m; 595 pkt_seq = q->ipqe_seq; 596 pkt_len += q->ipqe_len - overlap; 597 rcvoobyte -= overlap; 598 TCP_REASS_COUNTER_INCR(&tcp_reass_overlaptail); 599 goto free_ipqe; 600 } 601 /* 602 * RX'ed segment extends past the front of the 603 * fragment. Drop the overlapping bytes on the 604 * received packet. The packet will then be 605 * contatentated with this fragment a bit later. 606 */ 607 if (SEQ_GT(q->ipqe_seq, pkt_seq) && 608 SEQ_LT(q->ipqe_seq, pkt_seq + pkt_len)) { 609 int overlap = pkt_seq + pkt_len - q->ipqe_seq; 610 #ifdef TCPREASS_DEBUG 611 printf("tcp_reass[%p]: trim trailing %d bytes of %u:%u(%u)\n", 612 tp, overlap, 613 pkt_seq, pkt_seq + pkt_len, pkt_len); 614 #endif 615 m_adj(m, -overlap); 616 pkt_len -= overlap; 617 rcvpartdupbyte += overlap; 618 TCP_REASS_COUNTER_INCR(&tcp_reass_overlapfront); 619 rcvoobyte -= overlap; 620 } 621 /* 622 * If the received segment immediates precedes this 623 * fragment then tack the fragment onto this segment 624 * and reinsert the data. 625 */ 626 if (q->ipqe_seq == pkt_seq + pkt_len) { 627 #ifdef TCPREASS_DEBUG 628 printf("tcp_reass[%p]: append %u:%u(%u) to %u:%u(%u)\n", 629 tp, q->ipqe_seq, q->ipqe_seq + q->ipqe_len, q->ipqe_len, 630 pkt_seq, pkt_seq + pkt_len, pkt_len); 631 #endif 632 pkt_len += q->ipqe_len; 633 pkt_flags |= q->ipqe_flags; 634 m_cat(m, q->ipqe_m); 635 TAILQ_REMOVE(&tp->segq, q, ipqe_q); 636 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 637 tp->t_segqlen--; 638 KASSERT(tp->t_segqlen >= 0); 639 KASSERT(tp->t_segqlen != 0 || 640 (TAILQ_EMPTY(&tp->segq) && 641 TAILQ_EMPTY(&tp->timeq))); 642 if (tiqe == NULL) { 643 tiqe = q; 644 } else { 645 tcpipqent_free(q); 646 } 647 TCP_REASS_COUNTER_INCR(&tcp_reass_prepend); 648 break; 649 } 650 /* 651 * If the fragment is before the segment, remember it. 652 * When this loop is terminated, p will contain the 653 * pointer to fragment that is right before the received 654 * segment. 655 */ 656 if (SEQ_LEQ(q->ipqe_seq, pkt_seq)) 657 p = q; 658 659 continue; 660 661 /* 662 * This is a common operation. It also will allow 663 * to save doing a malloc/free in most instances. 664 */ 665 free_ipqe: 666 TAILQ_REMOVE(&tp->segq, q, ipqe_q); 667 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 668 tp->t_segqlen--; 669 KASSERT(tp->t_segqlen >= 0); 670 KASSERT(tp->t_segqlen != 0 || 671 (TAILQ_EMPTY(&tp->segq) && TAILQ_EMPTY(&tp->timeq))); 672 if (tiqe == NULL) { 673 tiqe = q; 674 } else { 675 tcpipqent_free(q); 676 } 677 } 678 679 #ifdef TCP_REASS_COUNTERS 680 if (count > 7) 681 TCP_REASS_COUNTER_INCR(&tcp_reass_iteration[0]); 682 else if (count > 0) 683 TCP_REASS_COUNTER_INCR(&tcp_reass_iteration[count]); 684 #endif 685 686 insert_it: 687 688 /* 689 * Allocate a new queue entry since the received segment did not 690 * collapse onto any other out-of-order block; thus we are allocating 691 * a new block. If it had collapsed, tiqe would not be NULL and 692 * we would be reusing it. 693 * XXX If we can't, just drop the packet. XXX 694 */ 695 if (tiqe == NULL) { 696 tiqe = tcpipqent_alloc(); 697 if (tiqe == NULL) { 698 tcpstat.tcps_rcvmemdrop++; 699 m_freem(m); 700 return (0); 701 } 702 } 703 704 /* 705 * Update the counters. 706 */ 707 tcpstat.tcps_rcvoopack++; 708 tcpstat.tcps_rcvoobyte += rcvoobyte; 709 if (rcvpartdupbyte) { 710 tcpstat.tcps_rcvpartduppack++; 711 tcpstat.tcps_rcvpartdupbyte += rcvpartdupbyte; 712 } 713 714 /* 715 * Insert the new fragment queue entry into both queues. 716 */ 717 tiqe->ipqe_m = m; 718 tiqe->ipre_mlast = m; 719 tiqe->ipqe_seq = pkt_seq; 720 tiqe->ipqe_len = pkt_len; 721 tiqe->ipqe_flags = pkt_flags; 722 if (p == NULL) { 723 TAILQ_INSERT_HEAD(&tp->segq, tiqe, ipqe_q); 724 #ifdef TCPREASS_DEBUG 725 if (tiqe->ipqe_seq != tp->rcv_nxt) 726 printf("tcp_reass[%p]: insert %u:%u(%u) at front\n", 727 tp, pkt_seq, pkt_seq + pkt_len, pkt_len); 728 #endif 729 } else { 730 TAILQ_INSERT_AFTER(&tp->segq, p, tiqe, ipqe_q); 731 #ifdef TCPREASS_DEBUG 732 printf("tcp_reass[%p]: insert %u:%u(%u) after %u:%u(%u)\n", 733 tp, pkt_seq, pkt_seq + pkt_len, pkt_len, 734 p->ipqe_seq, p->ipqe_seq + p->ipqe_len, p->ipqe_len); 735 #endif 736 } 737 tp->t_segqlen++; 738 739 skip_replacement: 740 741 TAILQ_INSERT_HEAD(&tp->timeq, tiqe, ipqe_timeq); 742 743 present: 744 /* 745 * Present data to user, advancing rcv_nxt through 746 * completed sequence space. 747 */ 748 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 749 return (0); 750 q = TAILQ_FIRST(&tp->segq); 751 if (q == NULL || q->ipqe_seq != tp->rcv_nxt) 752 return (0); 753 if (tp->t_state == TCPS_SYN_RECEIVED && q->ipqe_len) 754 return (0); 755 756 tp->rcv_nxt += q->ipqe_len; 757 pkt_flags = q->ipqe_flags & TH_FIN; 758 ND6_HINT(tp); 759 760 TAILQ_REMOVE(&tp->segq, q, ipqe_q); 761 TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); 762 tp->t_segqlen--; 763 KASSERT(tp->t_segqlen >= 0); 764 KASSERT(tp->t_segqlen != 0 || 765 (TAILQ_EMPTY(&tp->segq) && TAILQ_EMPTY(&tp->timeq))); 766 if (so->so_state & SS_CANTRCVMORE) 767 m_freem(q->ipqe_m); 768 else 769 sbappendstream(&so->so_rcv, q->ipqe_m); 770 tcpipqent_free(q); 771 sorwakeup(so); 772 return (pkt_flags); 773 } 774 775 #ifdef INET6 776 int 777 tcp6_input(struct mbuf **mp, int *offp, int proto) 778 { 779 struct mbuf *m = *mp; 780 781 /* 782 * draft-itojun-ipv6-tcp-to-anycast 783 * better place to put this in? 784 */ 785 if (m->m_flags & M_ANYCAST6) { 786 struct ip6_hdr *ip6; 787 if (m->m_len < sizeof(struct ip6_hdr)) { 788 if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) { 789 tcpstat.tcps_rcvshort++; 790 return IPPROTO_DONE; 791 } 792 } 793 ip6 = mtod(m, struct ip6_hdr *); 794 icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR, 795 (caddr_t)&ip6->ip6_dst - (caddr_t)ip6); 796 return IPPROTO_DONE; 797 } 798 799 tcp_input(m, *offp, proto); 800 return IPPROTO_DONE; 801 } 802 #endif 803 804 #ifdef INET 805 static void 806 tcp4_log_refused(const struct ip *ip, const struct tcphdr *th) 807 { 808 char src[4*sizeof "123"]; 809 char dst[4*sizeof "123"]; 810 811 if (ip) { 812 strlcpy(src, inet_ntoa(ip->ip_src), sizeof(src)); 813 strlcpy(dst, inet_ntoa(ip->ip_dst), sizeof(dst)); 814 } 815 else { 816 strlcpy(src, "(unknown)", sizeof(src)); 817 strlcpy(dst, "(unknown)", sizeof(dst)); 818 } 819 log(LOG_INFO, 820 "Connection attempt to TCP %s:%d from %s:%d\n", 821 dst, ntohs(th->th_dport), 822 src, ntohs(th->th_sport)); 823 } 824 #endif 825 826 #ifdef INET6 827 static void 828 tcp6_log_refused(const struct ip6_hdr *ip6, const struct tcphdr *th) 829 { 830 char src[INET6_ADDRSTRLEN]; 831 char dst[INET6_ADDRSTRLEN]; 832 833 if (ip6) { 834 strlcpy(src, ip6_sprintf(&ip6->ip6_src), sizeof(src)); 835 strlcpy(dst, ip6_sprintf(&ip6->ip6_dst), sizeof(dst)); 836 } 837 else { 838 strlcpy(src, "(unknown v6)", sizeof(src)); 839 strlcpy(dst, "(unknown v6)", sizeof(dst)); 840 } 841 log(LOG_INFO, 842 "Connection attempt to TCP [%s]:%d from [%s]:%d\n", 843 dst, ntohs(th->th_dport), 844 src, ntohs(th->th_sport)); 845 } 846 #endif 847 848 /* 849 * Checksum extended TCP header and data. 850 */ 851 int 852 tcp_input_checksum(int af, struct mbuf *m, const struct tcphdr *th __unused, 853 int toff, int off, int tlen) 854 { 855 856 /* 857 * XXX it's better to record and check if this mbuf is 858 * already checked. 859 */ 860 861 switch (af) { 862 #ifdef INET 863 case AF_INET: 864 switch (m->m_pkthdr.csum_flags & 865 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_TCPv4) | 866 M_CSUM_TCP_UDP_BAD | M_CSUM_DATA)) { 867 case M_CSUM_TCPv4|M_CSUM_TCP_UDP_BAD: 868 TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_bad); 869 goto badcsum; 870 871 case M_CSUM_TCPv4|M_CSUM_DATA: { 872 u_int32_t hw_csum = m->m_pkthdr.csum_data; 873 874 TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_data); 875 if (m->m_pkthdr.csum_flags & M_CSUM_NO_PSEUDOHDR) { 876 const struct ip *ip = 877 mtod(m, const struct ip *); 878 879 hw_csum = in_cksum_phdr(ip->ip_src.s_addr, 880 ip->ip_dst.s_addr, 881 htons(hw_csum + tlen + off + IPPROTO_TCP)); 882 } 883 if ((hw_csum ^ 0xffff) != 0) 884 goto badcsum; 885 break; 886 } 887 888 case M_CSUM_TCPv4: 889 /* Checksum was okay. */ 890 TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_ok); 891 break; 892 893 default: 894 /* 895 * Must compute it ourselves. Maybe skip checksum 896 * on loopback interfaces. 897 */ 898 if (__predict_true(!(m->m_pkthdr.rcvif->if_flags & 899 IFF_LOOPBACK) || 900 tcp_do_loopback_cksum)) { 901 TCP_CSUM_COUNTER_INCR(&tcp_swcsum); 902 if (in4_cksum(m, IPPROTO_TCP, toff, 903 tlen + off) != 0) 904 goto badcsum; 905 } 906 break; 907 } 908 break; 909 #endif /* INET4 */ 910 911 #ifdef INET6 912 case AF_INET6: 913 switch (m->m_pkthdr.csum_flags & 914 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_TCPv6) | 915 M_CSUM_TCP_UDP_BAD | M_CSUM_DATA)) { 916 case M_CSUM_TCPv6|M_CSUM_TCP_UDP_BAD: 917 TCP_CSUM_COUNTER_INCR(&tcp6_hwcsum_bad); 918 goto badcsum; 919 920 #if 0 /* notyet */ 921 case M_CSUM_TCPv6|M_CSUM_DATA: 922 #endif 923 924 case M_CSUM_TCPv6: 925 /* Checksum was okay. */ 926 TCP_CSUM_COUNTER_INCR(&tcp6_hwcsum_ok); 927 break; 928 929 default: 930 /* 931 * Must compute it ourselves. Maybe skip checksum 932 * on loopback interfaces. 933 */ 934 if (__predict_true((m->m_flags & M_LOOP) == 0 || 935 tcp_do_loopback_cksum)) { 936 TCP_CSUM_COUNTER_INCR(&tcp6_swcsum); 937 if (in6_cksum(m, IPPROTO_TCP, toff, 938 tlen + off) != 0) 939 goto badcsum; 940 } 941 } 942 break; 943 #endif /* INET6 */ 944 } 945 946 return 0; 947 948 badcsum: 949 tcpstat.tcps_rcvbadsum++; 950 return -1; 951 } 952 953 /* 954 * TCP input routine, follows pages 65-76 of RFC 793 very closely. 955 */ 956 void 957 tcp_input(struct mbuf *m, ...) 958 { 959 struct tcphdr *th; 960 struct ip *ip; 961 struct inpcb *inp; 962 #ifdef INET6 963 struct ip6_hdr *ip6; 964 struct in6pcb *in6p; 965 #endif 966 u_int8_t *optp = NULL; 967 int optlen = 0; 968 int len, tlen, toff, hdroptlen = 0; 969 struct tcpcb *tp = 0; 970 int tiflags; 971 struct socket *so = NULL; 972 int todrop, dupseg, acked, ourfinisacked, needoutput = 0; 973 #ifdef TCP_DEBUG 974 short ostate = 0; 975 #endif 976 u_long tiwin; 977 struct tcp_opt_info opti; 978 int off, iphlen; 979 va_list ap; 980 int af; /* af on the wire */ 981 struct mbuf *tcp_saveti = NULL; 982 uint32_t ts_rtt; 983 uint8_t iptos; 984 985 MCLAIM(m, &tcp_rx_mowner); 986 va_start(ap, m); 987 toff = va_arg(ap, int); 988 (void)va_arg(ap, int); /* ignore value, advance ap */ 989 va_end(ap); 990 991 tcpstat.tcps_rcvtotal++; 992 993 bzero(&opti, sizeof(opti)); 994 opti.ts_present = 0; 995 opti.maxseg = 0; 996 997 /* 998 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN. 999 * 1000 * TCP is, by definition, unicast, so we reject all 1001 * multicast outright. 1002 * 1003 * Note, there are additional src/dst address checks in 1004 * the AF-specific code below. 1005 */ 1006 if (m->m_flags & (M_BCAST|M_MCAST)) { 1007 /* XXX stat */ 1008 goto drop; 1009 } 1010 #ifdef INET6 1011 if (m->m_flags & M_ANYCAST6) { 1012 /* XXX stat */ 1013 goto drop; 1014 } 1015 #endif 1016 1017 /* 1018 * Get IP and TCP header. 1019 * Note: IP leaves IP header in first mbuf. 1020 */ 1021 ip = mtod(m, struct ip *); 1022 #ifdef INET6 1023 ip6 = NULL; 1024 #endif 1025 switch (ip->ip_v) { 1026 #ifdef INET 1027 case 4: 1028 af = AF_INET; 1029 iphlen = sizeof(struct ip); 1030 ip = mtod(m, struct ip *); 1031 IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, 1032 sizeof(struct tcphdr)); 1033 if (th == NULL) { 1034 tcpstat.tcps_rcvshort++; 1035 return; 1036 } 1037 /* We do the checksum after PCB lookup... */ 1038 len = ntohs(ip->ip_len); 1039 tlen = len - toff; 1040 iptos = ip->ip_tos; 1041 break; 1042 #endif 1043 #ifdef INET6 1044 case 6: 1045 ip = NULL; 1046 iphlen = sizeof(struct ip6_hdr); 1047 af = AF_INET6; 1048 ip6 = mtod(m, struct ip6_hdr *); 1049 IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, 1050 sizeof(struct tcphdr)); 1051 if (th == NULL) { 1052 tcpstat.tcps_rcvshort++; 1053 return; 1054 } 1055 1056 /* Be proactive about malicious use of IPv4 mapped address */ 1057 if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) || 1058 IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) { 1059 /* XXX stat */ 1060 goto drop; 1061 } 1062 1063 /* 1064 * Be proactive about unspecified IPv6 address in source. 1065 * As we use all-zero to indicate unbounded/unconnected pcb, 1066 * unspecified IPv6 address can be used to confuse us. 1067 * 1068 * Note that packets with unspecified IPv6 destination is 1069 * already dropped in ip6_input. 1070 */ 1071 if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 1072 /* XXX stat */ 1073 goto drop; 1074 } 1075 1076 /* 1077 * Make sure destination address is not multicast. 1078 * Source address checked in ip6_input(). 1079 */ 1080 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) { 1081 /* XXX stat */ 1082 goto drop; 1083 } 1084 1085 /* We do the checksum after PCB lookup... */ 1086 len = m->m_pkthdr.len; 1087 tlen = len - toff; 1088 iptos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 1089 break; 1090 #endif 1091 default: 1092 m_freem(m); 1093 return; 1094 } 1095 1096 KASSERT(TCP_HDR_ALIGNED_P(th)); 1097 1098 /* 1099 * Check that TCP offset makes sense, 1100 * pull out TCP options and adjust length. XXX 1101 */ 1102 off = th->th_off << 2; 1103 if (off < sizeof (struct tcphdr) || off > tlen) { 1104 tcpstat.tcps_rcvbadoff++; 1105 goto drop; 1106 } 1107 tlen -= off; 1108 1109 /* 1110 * tcp_input() has been modified to use tlen to mean the TCP data 1111 * length throughout the function. Other functions can use 1112 * m->m_pkthdr.len as the basis for calculating the TCP data length. 1113 * rja 1114 */ 1115 1116 if (off > sizeof (struct tcphdr)) { 1117 IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, off); 1118 if (th == NULL) { 1119 tcpstat.tcps_rcvshort++; 1120 return; 1121 } 1122 /* 1123 * NOTE: ip/ip6 will not be affected by m_pulldown() 1124 * (as they're before toff) and we don't need to update those. 1125 */ 1126 KASSERT(TCP_HDR_ALIGNED_P(th)); 1127 optlen = off - sizeof (struct tcphdr); 1128 optp = ((u_int8_t *)th) + sizeof(struct tcphdr); 1129 /* 1130 * Do quick retrieval of timestamp options ("options 1131 * prediction?"). If timestamp is the only option and it's 1132 * formatted as recommended in RFC 1323 appendix A, we 1133 * quickly get the values now and not bother calling 1134 * tcp_dooptions(), etc. 1135 */ 1136 if ((optlen == TCPOLEN_TSTAMP_APPA || 1137 (optlen > TCPOLEN_TSTAMP_APPA && 1138 optp[TCPOLEN_TSTAMP_APPA] == TCPOPT_EOL)) && 1139 *(u_int32_t *)optp == htonl(TCPOPT_TSTAMP_HDR) && 1140 (th->th_flags & TH_SYN) == 0) { 1141 opti.ts_present = 1; 1142 opti.ts_val = ntohl(*(u_int32_t *)(optp + 4)); 1143 opti.ts_ecr = ntohl(*(u_int32_t *)(optp + 8)); 1144 optp = NULL; /* we've parsed the options */ 1145 } 1146 } 1147 tiflags = th->th_flags; 1148 1149 /* 1150 * Locate pcb for segment. 1151 */ 1152 findpcb: 1153 inp = NULL; 1154 #ifdef INET6 1155 in6p = NULL; 1156 #endif 1157 switch (af) { 1158 #ifdef INET 1159 case AF_INET: 1160 inp = in_pcblookup_connect(&tcbtable, ip->ip_src, th->th_sport, 1161 ip->ip_dst, th->th_dport); 1162 if (inp == 0) { 1163 ++tcpstat.tcps_pcbhashmiss; 1164 inp = in_pcblookup_bind(&tcbtable, ip->ip_dst, th->th_dport); 1165 } 1166 #ifdef INET6 1167 if (inp == 0) { 1168 struct in6_addr s, d; 1169 1170 /* mapped addr case */ 1171 bzero(&s, sizeof(s)); 1172 s.s6_addr16[5] = htons(0xffff); 1173 bcopy(&ip->ip_src, &s.s6_addr32[3], sizeof(ip->ip_src)); 1174 bzero(&d, sizeof(d)); 1175 d.s6_addr16[5] = htons(0xffff); 1176 bcopy(&ip->ip_dst, &d.s6_addr32[3], sizeof(ip->ip_dst)); 1177 in6p = in6_pcblookup_connect(&tcbtable, &s, 1178 th->th_sport, &d, th->th_dport, 0); 1179 if (in6p == 0) { 1180 ++tcpstat.tcps_pcbhashmiss; 1181 in6p = in6_pcblookup_bind(&tcbtable, &d, 1182 th->th_dport, 0); 1183 } 1184 } 1185 #endif 1186 #ifndef INET6 1187 if (inp == 0) 1188 #else 1189 if (inp == 0 && in6p == 0) 1190 #endif 1191 { 1192 ++tcpstat.tcps_noport; 1193 if (tcp_log_refused && 1194 (tiflags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN) { 1195 tcp4_log_refused(ip, th); 1196 } 1197 TCP_FIELDS_TO_HOST(th); 1198 goto dropwithreset_ratelim; 1199 } 1200 #if defined(IPSEC) || defined(FAST_IPSEC) 1201 if (inp && (inp->inp_socket->so_options & SO_ACCEPTCONN) == 0 && 1202 ipsec4_in_reject(m, inp)) { 1203 ipsecstat.in_polvio++; 1204 goto drop; 1205 } 1206 #ifdef INET6 1207 else if (in6p && 1208 (in6p->in6p_socket->so_options & SO_ACCEPTCONN) == 0 && 1209 ipsec4_in_reject_so(m, in6p->in6p_socket)) { 1210 ipsecstat.in_polvio++; 1211 goto drop; 1212 } 1213 #endif 1214 #endif /*IPSEC*/ 1215 break; 1216 #endif /*INET*/ 1217 #ifdef INET6 1218 case AF_INET6: 1219 { 1220 int faith; 1221 1222 #if defined(NFAITH) && NFAITH > 0 1223 faith = faithprefix(&ip6->ip6_dst); 1224 #else 1225 faith = 0; 1226 #endif 1227 in6p = in6_pcblookup_connect(&tcbtable, &ip6->ip6_src, 1228 th->th_sport, &ip6->ip6_dst, th->th_dport, faith); 1229 if (in6p == NULL) { 1230 ++tcpstat.tcps_pcbhashmiss; 1231 in6p = in6_pcblookup_bind(&tcbtable, &ip6->ip6_dst, 1232 th->th_dport, faith); 1233 } 1234 if (in6p == NULL) { 1235 ++tcpstat.tcps_noport; 1236 if (tcp_log_refused && 1237 (tiflags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN) { 1238 tcp6_log_refused(ip6, th); 1239 } 1240 TCP_FIELDS_TO_HOST(th); 1241 goto dropwithreset_ratelim; 1242 } 1243 #if defined(IPSEC) || defined(FAST_IPSEC) 1244 if ((in6p->in6p_socket->so_options & SO_ACCEPTCONN) == 0 && 1245 ipsec6_in_reject(m, in6p)) { 1246 ipsec6stat.in_polvio++; 1247 goto drop; 1248 } 1249 #endif /*IPSEC*/ 1250 break; 1251 } 1252 #endif 1253 } 1254 1255 /* 1256 * If the state is CLOSED (i.e., TCB does not exist) then 1257 * all data in the incoming segment is discarded. 1258 * If the TCB exists but is in CLOSED state, it is embryonic, 1259 * but should either do a listen or a connect soon. 1260 */ 1261 tp = NULL; 1262 so = NULL; 1263 if (inp) { 1264 tp = intotcpcb(inp); 1265 so = inp->inp_socket; 1266 } 1267 #ifdef INET6 1268 else if (in6p) { 1269 tp = in6totcpcb(in6p); 1270 so = in6p->in6p_socket; 1271 } 1272 #endif 1273 if (tp == 0) { 1274 TCP_FIELDS_TO_HOST(th); 1275 goto dropwithreset_ratelim; 1276 } 1277 if (tp->t_state == TCPS_CLOSED) 1278 goto drop; 1279 1280 /* 1281 * Checksum extended TCP header and data. 1282 */ 1283 if (tcp_input_checksum(af, m, th, toff, off, tlen)) 1284 goto badcsum; 1285 1286 TCP_FIELDS_TO_HOST(th); 1287 1288 /* Unscale the window into a 32-bit value. */ 1289 if ((tiflags & TH_SYN) == 0) 1290 tiwin = th->th_win << tp->snd_scale; 1291 else 1292 tiwin = th->th_win; 1293 1294 #ifdef INET6 1295 /* save packet options if user wanted */ 1296 if (in6p && (in6p->in6p_flags & IN6P_CONTROLOPTS)) { 1297 if (in6p->in6p_options) { 1298 m_freem(in6p->in6p_options); 1299 in6p->in6p_options = 0; 1300 } 1301 KASSERT(ip6 != NULL); 1302 ip6_savecontrol(in6p, &in6p->in6p_options, ip6, m); 1303 } 1304 #endif 1305 1306 if (so->so_options & (SO_DEBUG|SO_ACCEPTCONN)) { 1307 union syn_cache_sa src; 1308 union syn_cache_sa dst; 1309 1310 bzero(&src, sizeof(src)); 1311 bzero(&dst, sizeof(dst)); 1312 switch (af) { 1313 #ifdef INET 1314 case AF_INET: 1315 src.sin.sin_len = sizeof(struct sockaddr_in); 1316 src.sin.sin_family = AF_INET; 1317 src.sin.sin_addr = ip->ip_src; 1318 src.sin.sin_port = th->th_sport; 1319 1320 dst.sin.sin_len = sizeof(struct sockaddr_in); 1321 dst.sin.sin_family = AF_INET; 1322 dst.sin.sin_addr = ip->ip_dst; 1323 dst.sin.sin_port = th->th_dport; 1324 break; 1325 #endif 1326 #ifdef INET6 1327 case AF_INET6: 1328 src.sin6.sin6_len = sizeof(struct sockaddr_in6); 1329 src.sin6.sin6_family = AF_INET6; 1330 src.sin6.sin6_addr = ip6->ip6_src; 1331 src.sin6.sin6_port = th->th_sport; 1332 1333 dst.sin6.sin6_len = sizeof(struct sockaddr_in6); 1334 dst.sin6.sin6_family = AF_INET6; 1335 dst.sin6.sin6_addr = ip6->ip6_dst; 1336 dst.sin6.sin6_port = th->th_dport; 1337 break; 1338 #endif /* INET6 */ 1339 default: 1340 goto badsyn; /*sanity*/ 1341 } 1342 1343 if (so->so_options & SO_DEBUG) { 1344 #ifdef TCP_DEBUG 1345 ostate = tp->t_state; 1346 #endif 1347 1348 tcp_saveti = NULL; 1349 if (iphlen + sizeof(struct tcphdr) > MHLEN) 1350 goto nosave; 1351 1352 if (m->m_len > iphlen && (m->m_flags & M_EXT) == 0) { 1353 tcp_saveti = m_copym(m, 0, iphlen, M_DONTWAIT); 1354 if (!tcp_saveti) 1355 goto nosave; 1356 } else { 1357 MGETHDR(tcp_saveti, M_DONTWAIT, MT_HEADER); 1358 if (!tcp_saveti) 1359 goto nosave; 1360 MCLAIM(m, &tcp_mowner); 1361 tcp_saveti->m_len = iphlen; 1362 m_copydata(m, 0, iphlen, 1363 mtod(tcp_saveti, caddr_t)); 1364 } 1365 1366 if (M_TRAILINGSPACE(tcp_saveti) < sizeof(struct tcphdr)) { 1367 m_freem(tcp_saveti); 1368 tcp_saveti = NULL; 1369 } else { 1370 tcp_saveti->m_len += sizeof(struct tcphdr); 1371 bcopy(th, mtod(tcp_saveti, caddr_t) + iphlen, 1372 sizeof(struct tcphdr)); 1373 } 1374 nosave:; 1375 } 1376 if (so->so_options & SO_ACCEPTCONN) { 1377 if ((tiflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) { 1378 if (tiflags & TH_RST) { 1379 syn_cache_reset(&src.sa, &dst.sa, th); 1380 } else if ((tiflags & (TH_ACK|TH_SYN)) == 1381 (TH_ACK|TH_SYN)) { 1382 /* 1383 * Received a SYN,ACK. This should 1384 * never happen while we are in 1385 * LISTEN. Send an RST. 1386 */ 1387 goto badsyn; 1388 } else if (tiflags & TH_ACK) { 1389 so = syn_cache_get(&src.sa, &dst.sa, 1390 th, toff, tlen, so, m); 1391 if (so == NULL) { 1392 /* 1393 * We don't have a SYN for 1394 * this ACK; send an RST. 1395 */ 1396 goto badsyn; 1397 } else if (so == 1398 (struct socket *)(-1)) { 1399 /* 1400 * We were unable to create 1401 * the connection. If the 1402 * 3-way handshake was 1403 * completed, and RST has 1404 * been sent to the peer. 1405 * Since the mbuf might be 1406 * in use for the reply, 1407 * do not free it. 1408 */ 1409 m = NULL; 1410 } else { 1411 /* 1412 * We have created a 1413 * full-blown connection. 1414 */ 1415 tp = NULL; 1416 inp = NULL; 1417 #ifdef INET6 1418 in6p = NULL; 1419 #endif 1420 switch (so->so_proto->pr_domain->dom_family) { 1421 #ifdef INET 1422 case AF_INET: 1423 inp = sotoinpcb(so); 1424 tp = intotcpcb(inp); 1425 break; 1426 #endif 1427 #ifdef INET6 1428 case AF_INET6: 1429 in6p = sotoin6pcb(so); 1430 tp = in6totcpcb(in6p); 1431 break; 1432 #endif 1433 } 1434 if (tp == NULL) 1435 goto badsyn; /*XXX*/ 1436 tiwin <<= tp->snd_scale; 1437 goto after_listen; 1438 } 1439 } else { 1440 /* 1441 * None of RST, SYN or ACK was set. 1442 * This is an invalid packet for a 1443 * TCB in LISTEN state. Send a RST. 1444 */ 1445 goto badsyn; 1446 } 1447 } else { 1448 /* 1449 * Received a SYN. 1450 * 1451 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN 1452 */ 1453 if (m->m_flags & (M_BCAST|M_MCAST)) 1454 goto drop; 1455 1456 switch (af) { 1457 #ifdef INET6 1458 case AF_INET6: 1459 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) 1460 goto drop; 1461 break; 1462 #endif /* INET6 */ 1463 case AF_INET: 1464 if (IN_MULTICAST(ip->ip_dst.s_addr) || 1465 in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) 1466 goto drop; 1467 break; 1468 } 1469 1470 #ifdef INET6 1471 /* 1472 * If deprecated address is forbidden, we do 1473 * not accept SYN to deprecated interface 1474 * address to prevent any new inbound 1475 * connection from getting established. 1476 * When we do not accept SYN, we send a TCP 1477 * RST, with deprecated source address (instead 1478 * of dropping it). We compromise it as it is 1479 * much better for peer to send a RST, and 1480 * RST will be the final packet for the 1481 * exchange. 1482 * 1483 * If we do not forbid deprecated addresses, we 1484 * accept the SYN packet. RFC2462 does not 1485 * suggest dropping SYN in this case. 1486 * If we decipher RFC2462 5.5.4, it says like 1487 * this: 1488 * 1. use of deprecated addr with existing 1489 * communication is okay - "SHOULD continue 1490 * to be used" 1491 * 2. use of it with new communication: 1492 * (2a) "SHOULD NOT be used if alternate 1493 * address with sufficient scope is 1494 * available" 1495 * (2b) nothing mentioned otherwise. 1496 * Here we fall into (2b) case as we have no 1497 * choice in our source address selection - we 1498 * must obey the peer. 1499 * 1500 * The wording in RFC2462 is confusing, and 1501 * there are multiple description text for 1502 * deprecated address handling - worse, they 1503 * are not exactly the same. I believe 5.5.4 1504 * is the best one, so we follow 5.5.4. 1505 */ 1506 if (af == AF_INET6 && !ip6_use_deprecated) { 1507 struct in6_ifaddr *ia6; 1508 if ((ia6 = in6ifa_ifpwithaddr(m->m_pkthdr.rcvif, 1509 &ip6->ip6_dst)) && 1510 (ia6->ia6_flags & IN6_IFF_DEPRECATED)) { 1511 tp = NULL; 1512 goto dropwithreset; 1513 } 1514 } 1515 #endif 1516 1517 #ifdef IPSEC 1518 switch (af) { 1519 #ifdef INET 1520 case AF_INET: 1521 if (ipsec4_in_reject_so(m, so)) { 1522 ipsecstat.in_polvio++; 1523 tp = NULL; 1524 goto dropwithreset; 1525 } 1526 break; 1527 #endif 1528 #ifdef INET6 1529 case AF_INET6: 1530 if (ipsec6_in_reject_so(m, so)) { 1531 ipsec6stat.in_polvio++; 1532 tp = NULL; 1533 goto dropwithreset; 1534 } 1535 break; 1536 #endif 1537 } 1538 #endif 1539 1540 /* 1541 * LISTEN socket received a SYN 1542 * from itself? This can't possibly 1543 * be valid; drop the packet. 1544 */ 1545 if (th->th_sport == th->th_dport) { 1546 int i; 1547 1548 switch (af) { 1549 #ifdef INET 1550 case AF_INET: 1551 i = in_hosteq(ip->ip_src, ip->ip_dst); 1552 break; 1553 #endif 1554 #ifdef INET6 1555 case AF_INET6: 1556 i = IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &ip6->ip6_dst); 1557 break; 1558 #endif 1559 default: 1560 i = 1; 1561 } 1562 if (i) { 1563 tcpstat.tcps_badsyn++; 1564 goto drop; 1565 } 1566 } 1567 1568 /* 1569 * SYN looks ok; create compressed TCP 1570 * state for it. 1571 */ 1572 if (so->so_qlen <= so->so_qlimit && 1573 syn_cache_add(&src.sa, &dst.sa, th, tlen, 1574 so, m, optp, optlen, &opti)) 1575 m = NULL; 1576 } 1577 goto drop; 1578 } 1579 } 1580 1581 after_listen: 1582 #ifdef DIAGNOSTIC 1583 /* 1584 * Should not happen now that all embryonic connections 1585 * are handled with compressed state. 1586 */ 1587 if (tp->t_state == TCPS_LISTEN) 1588 panic("tcp_input: TCPS_LISTEN"); 1589 #endif 1590 1591 /* 1592 * Segment received on connection. 1593 * Reset idle time and keep-alive timer. 1594 */ 1595 tp->t_rcvtime = tcp_now; 1596 if (TCPS_HAVEESTABLISHED(tp->t_state)) 1597 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle); 1598 1599 /* 1600 * Process options. 1601 */ 1602 #ifdef TCP_SIGNATURE 1603 if (optp || (tp->t_flags & TF_SIGNATURE)) 1604 #else 1605 if (optp) 1606 #endif 1607 if (tcp_dooptions(tp, optp, optlen, th, m, toff, &opti) < 0) 1608 goto drop; 1609 1610 if (TCP_SACK_ENABLED(tp)) { 1611 tcp_del_sackholes(tp, th); 1612 } 1613 1614 if (TCP_ECN_ALLOWED(tp)) { 1615 switch (iptos & IPTOS_ECN_MASK) { 1616 case IPTOS_ECN_CE: 1617 tp->t_flags |= TF_ECN_SND_ECE; 1618 tcpstat.tcps_ecn_ce++; 1619 break; 1620 case IPTOS_ECN_ECT0: 1621 tcpstat.tcps_ecn_ect++; 1622 break; 1623 case IPTOS_ECN_ECT1: 1624 /* XXX: ignore for now -- rpaulo */ 1625 break; 1626 } 1627 1628 if (tiflags & TH_CWR) 1629 tp->t_flags &= ~TF_ECN_SND_ECE; 1630 1631 /* 1632 * Congestion experienced. 1633 * Ignore if we are already trying to recover. 1634 */ 1635 if ((tiflags & TH_ECE) && SEQ_GEQ(tp->snd_una, tp->snd_recover)) 1636 tcp_reno_congestion_exp(tp); 1637 } 1638 1639 if (opti.ts_present && opti.ts_ecr) { 1640 /* 1641 * Calculate the RTT from the returned time stamp and the 1642 * connection's time base. If the time stamp is later than 1643 * the current time, or is extremely old, fall back to non-1323 1644 * RTT calculation. Since ts_ecr is unsigned, we can test both 1645 * at the same time. 1646 */ 1647 ts_rtt = TCP_TIMESTAMP(tp) - opti.ts_ecr + 1; 1648 if (ts_rtt > TCP_PAWS_IDLE) 1649 ts_rtt = 0; 1650 } else { 1651 ts_rtt = 0; 1652 } 1653 1654 /* 1655 * Header prediction: check for the two common cases 1656 * of a uni-directional data xfer. If the packet has 1657 * no control flags, is in-sequence, the window didn't 1658 * change and we're not retransmitting, it's a 1659 * candidate. If the length is zero and the ack moved 1660 * forward, we're the sender side of the xfer. Just 1661 * free the data acked & wake any higher level process 1662 * that was blocked waiting for space. If the length 1663 * is non-zero and the ack didn't move, we're the 1664 * receiver side. If we're getting packets in-order 1665 * (the reassembly queue is empty), add the data to 1666 * the socket buffer and note that we need a delayed ack. 1667 */ 1668 if (tp->t_state == TCPS_ESTABLISHED && 1669 (tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ECE|TH_CWR|TH_ACK)) 1670 == TH_ACK && 1671 (!opti.ts_present || TSTMP_GEQ(opti.ts_val, tp->ts_recent)) && 1672 th->th_seq == tp->rcv_nxt && 1673 tiwin && tiwin == tp->snd_wnd && 1674 tp->snd_nxt == tp->snd_max) { 1675 1676 /* 1677 * If last ACK falls within this segment's sequence numbers, 1678 * record the timestamp. 1679 * NOTE: 1680 * 1) That the test incorporates suggestions from the latest 1681 * proposal of the tcplw (at) cray.com list (Braden 1993/04/26). 1682 * 2) That updating only on newer timestamps interferes with 1683 * our earlier PAWS tests, so this check should be solely 1684 * predicated on the sequence space of this segment. 1685 * 3) That we modify the segment boundary check to be 1686 * Last.ACK.Sent <= SEG.SEQ + SEG.Len 1687 * instead of RFC1323's 1688 * Last.ACK.Sent < SEG.SEQ + SEG.Len, 1689 * This modified check allows us to overcome RFC1323's 1690 * limitations as described in Stevens TCP/IP Illustrated 1691 * Vol. 2 p.869. In such cases, we can still calculate the 1692 * RTT correctly when RCV.NXT == Last.ACK.Sent. 1693 */ 1694 if (opti.ts_present && 1695 SEQ_LEQ(th->th_seq, tp->last_ack_sent) && 1696 SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + 1697 ((tiflags & (TH_SYN|TH_FIN)) != 0))) { 1698 tp->ts_recent_age = tcp_now; 1699 tp->ts_recent = opti.ts_val; 1700 } 1701 1702 if (tlen == 0) { 1703 /* Ack prediction. */ 1704 if (SEQ_GT(th->th_ack, tp->snd_una) && 1705 SEQ_LEQ(th->th_ack, tp->snd_max) && 1706 tp->snd_cwnd >= tp->snd_wnd && 1707 tp->t_partialacks < 0) { 1708 /* 1709 * this is a pure ack for outstanding data. 1710 */ 1711 ++tcpstat.tcps_predack; 1712 if (ts_rtt) 1713 tcp_xmit_timer(tp, ts_rtt); 1714 else if (tp->t_rtttime && 1715 SEQ_GT(th->th_ack, tp->t_rtseq)) 1716 tcp_xmit_timer(tp, 1717 tcp_now - tp->t_rtttime); 1718 acked = th->th_ack - tp->snd_una; 1719 tcpstat.tcps_rcvackpack++; 1720 tcpstat.tcps_rcvackbyte += acked; 1721 ND6_HINT(tp); 1722 1723 if (acked > (tp->t_lastoff - tp->t_inoff)) 1724 tp->t_lastm = NULL; 1725 sbdrop(&so->so_snd, acked); 1726 tp->t_lastoff -= acked; 1727 1728 ICMP_CHECK(tp, th, acked); 1729 1730 tp->snd_una = th->th_ack; 1731 tp->snd_fack = tp->snd_una; 1732 if (SEQ_LT(tp->snd_high, tp->snd_una)) 1733 tp->snd_high = tp->snd_una; 1734 m_freem(m); 1735 1736 /* 1737 * If all outstanding data are acked, stop 1738 * retransmit timer, otherwise restart timer 1739 * using current (possibly backed-off) value. 1740 * If process is waiting for space, 1741 * wakeup/selwakeup/signal. If data 1742 * are ready to send, let tcp_output 1743 * decide between more output or persist. 1744 */ 1745 if (tp->snd_una == tp->snd_max) 1746 TCP_TIMER_DISARM(tp, TCPT_REXMT); 1747 else if (TCP_TIMER_ISARMED(tp, 1748 TCPT_PERSIST) == 0) 1749 TCP_TIMER_ARM(tp, TCPT_REXMT, 1750 tp->t_rxtcur); 1751 1752 sowwakeup(so); 1753 if (so->so_snd.sb_cc) 1754 (void) tcp_output(tp); 1755 if (tcp_saveti) 1756 m_freem(tcp_saveti); 1757 return; 1758 } 1759 } else if (th->th_ack == tp->snd_una && 1760 TAILQ_FIRST(&tp->segq) == NULL && 1761 tlen <= sbspace(&so->so_rcv)) { 1762 /* 1763 * this is a pure, in-sequence data packet 1764 * with nothing on the reassembly queue and 1765 * we have enough buffer space to take it. 1766 */ 1767 ++tcpstat.tcps_preddat; 1768 tp->rcv_nxt += tlen; 1769 tcpstat.tcps_rcvpack++; 1770 tcpstat.tcps_rcvbyte += tlen; 1771 ND6_HINT(tp); 1772 /* 1773 * Drop TCP, IP headers and TCP options then add data 1774 * to socket buffer. 1775 */ 1776 if (so->so_state & SS_CANTRCVMORE) 1777 m_freem(m); 1778 else { 1779 m_adj(m, toff + off); 1780 sbappendstream(&so->so_rcv, m); 1781 } 1782 sorwakeup(so); 1783 TCP_SETUP_ACK(tp, th); 1784 if (tp->t_flags & TF_ACKNOW) 1785 (void) tcp_output(tp); 1786 if (tcp_saveti) 1787 m_freem(tcp_saveti); 1788 return; 1789 } 1790 } 1791 1792 /* 1793 * Compute mbuf offset to TCP data segment. 1794 */ 1795 hdroptlen = toff + off; 1796 1797 /* 1798 * Calculate amount of space in receive window, 1799 * and then do TCP input processing. 1800 * Receive window is amount of space in rcv queue, 1801 * but not less than advertised window. 1802 */ 1803 { int win; 1804 1805 win = sbspace(&so->so_rcv); 1806 if (win < 0) 1807 win = 0; 1808 tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt)); 1809 } 1810 1811 switch (tp->t_state) { 1812 /* 1813 * If the state is SYN_SENT: 1814 * if seg contains an ACK, but not for our SYN, drop the input. 1815 * if seg contains a RST, then drop the connection. 1816 * if seg does not contain SYN, then drop it. 1817 * Otherwise this is an acceptable SYN segment 1818 * initialize tp->rcv_nxt and tp->irs 1819 * if seg contains ack then advance tp->snd_una 1820 * if seg contains a ECE and ECN support is enabled, the stream 1821 * is ECN capable. 1822 * if SYN has been acked change to ESTABLISHED else SYN_RCVD state 1823 * arrange for segment to be acked (eventually) 1824 * continue processing rest of data/controls, beginning with URG 1825 */ 1826 case TCPS_SYN_SENT: 1827 if ((tiflags & TH_ACK) && 1828 (SEQ_LEQ(th->th_ack, tp->iss) || 1829 SEQ_GT(th->th_ack, tp->snd_max))) 1830 goto dropwithreset; 1831 if (tiflags & TH_RST) { 1832 if (tiflags & TH_ACK) 1833 tp = tcp_drop(tp, ECONNREFUSED); 1834 goto drop; 1835 } 1836 if ((tiflags & TH_SYN) == 0) 1837 goto drop; 1838 if (tiflags & TH_ACK) { 1839 tp->snd_una = th->th_ack; 1840 if (SEQ_LT(tp->snd_nxt, tp->snd_una)) 1841 tp->snd_nxt = tp->snd_una; 1842 if (SEQ_LT(tp->snd_high, tp->snd_una)) 1843 tp->snd_high = tp->snd_una; 1844 TCP_TIMER_DISARM(tp, TCPT_REXMT); 1845 1846 if ((tiflags & TH_ECE) && tcp_do_ecn) { 1847 tp->t_flags |= TF_ECN_PERMIT; 1848 tcpstat.tcps_ecn_shs++; 1849 } 1850 1851 } 1852 tp->irs = th->th_seq; 1853 tcp_rcvseqinit(tp); 1854 tp->t_flags |= TF_ACKNOW; 1855 tcp_mss_from_peer(tp, opti.maxseg); 1856 1857 /* 1858 * Initialize the initial congestion window. If we 1859 * had to retransmit the SYN, we must initialize cwnd 1860 * to 1 segment (i.e. the Loss Window). 1861 */ 1862 if (tp->t_flags & TF_SYN_REXMT) 1863 tp->snd_cwnd = tp->t_peermss; 1864 else { 1865 int ss = tcp_init_win; 1866 #ifdef INET 1867 if (inp != NULL && in_localaddr(inp->inp_faddr)) 1868 ss = tcp_init_win_local; 1869 #endif 1870 #ifdef INET6 1871 if (in6p != NULL && in6_localaddr(&in6p->in6p_faddr)) 1872 ss = tcp_init_win_local; 1873 #endif 1874 tp->snd_cwnd = TCP_INITIAL_WINDOW(ss, tp->t_peermss); 1875 } 1876 1877 tcp_rmx_rtt(tp); 1878 if (tiflags & TH_ACK) { 1879 tcpstat.tcps_connects++; 1880 soisconnected(so); 1881 tcp_established(tp); 1882 /* Do window scaling on this connection? */ 1883 if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == 1884 (TF_RCVD_SCALE|TF_REQ_SCALE)) { 1885 tp->snd_scale = tp->requested_s_scale; 1886 tp->rcv_scale = tp->request_r_scale; 1887 } 1888 TCP_REASS_LOCK(tp); 1889 (void) tcp_reass(tp, NULL, (struct mbuf *)0, &tlen); 1890 TCP_REASS_UNLOCK(tp); 1891 /* 1892 * if we didn't have to retransmit the SYN, 1893 * use its rtt as our initial srtt & rtt var. 1894 */ 1895 if (tp->t_rtttime) 1896 tcp_xmit_timer(tp, tcp_now - tp->t_rtttime); 1897 } else 1898 tp->t_state = TCPS_SYN_RECEIVED; 1899 1900 /* 1901 * Advance th->th_seq to correspond to first data byte. 1902 * If data, trim to stay within window, 1903 * dropping FIN if necessary. 1904 */ 1905 th->th_seq++; 1906 if (tlen > tp->rcv_wnd) { 1907 todrop = tlen - tp->rcv_wnd; 1908 m_adj(m, -todrop); 1909 tlen = tp->rcv_wnd; 1910 tiflags &= ~TH_FIN; 1911 tcpstat.tcps_rcvpackafterwin++; 1912 tcpstat.tcps_rcvbyteafterwin += todrop; 1913 } 1914 tp->snd_wl1 = th->th_seq - 1; 1915 tp->rcv_up = th->th_seq; 1916 goto step6; 1917 1918 /* 1919 * If the state is SYN_RECEIVED: 1920 * If seg contains an ACK, but not for our SYN, drop the input 1921 * and generate an RST. See page 36, rfc793 1922 */ 1923 case TCPS_SYN_RECEIVED: 1924 if ((tiflags & TH_ACK) && 1925 (SEQ_LEQ(th->th_ack, tp->iss) || 1926 SEQ_GT(th->th_ack, tp->snd_max))) 1927 goto dropwithreset; 1928 break; 1929 } 1930 1931 /* 1932 * States other than LISTEN or SYN_SENT. 1933 * First check timestamp, if present. 1934 * Then check that at least some bytes of segment are within 1935 * receive window. If segment begins before rcv_nxt, 1936 * drop leading data (and SYN); if nothing left, just ack. 1937 * 1938 * RFC 1323 PAWS: If we have a timestamp reply on this segment 1939 * and it's less than ts_recent, drop it. 1940 */ 1941 if (opti.ts_present && (tiflags & TH_RST) == 0 && tp->ts_recent && 1942 TSTMP_LT(opti.ts_val, tp->ts_recent)) { 1943 1944 /* Check to see if ts_recent is over 24 days old. */ 1945 if (tcp_now - tp->ts_recent_age > TCP_PAWS_IDLE) { 1946 /* 1947 * Invalidate ts_recent. If this segment updates 1948 * ts_recent, the age will be reset later and ts_recent 1949 * will get a valid value. If it does not, setting 1950 * ts_recent to zero will at least satisfy the 1951 * requirement that zero be placed in the timestamp 1952 * echo reply when ts_recent isn't valid. The 1953 * age isn't reset until we get a valid ts_recent 1954 * because we don't want out-of-order segments to be 1955 * dropped when ts_recent is old. 1956 */ 1957 tp->ts_recent = 0; 1958 } else { 1959 tcpstat.tcps_rcvduppack++; 1960 tcpstat.tcps_rcvdupbyte += tlen; 1961 tcpstat.tcps_pawsdrop++; 1962 tcp_new_dsack(tp, th->th_seq, tlen); 1963 goto dropafterack; 1964 } 1965 } 1966 1967 todrop = tp->rcv_nxt - th->th_seq; 1968 dupseg = FALSE; 1969 if (todrop > 0) { 1970 if (tiflags & TH_SYN) { 1971 tiflags &= ~TH_SYN; 1972 th->th_seq++; 1973 if (th->th_urp > 1) 1974 th->th_urp--; 1975 else { 1976 tiflags &= ~TH_URG; 1977 th->th_urp = 0; 1978 } 1979 todrop--; 1980 } 1981 if (todrop > tlen || 1982 (todrop == tlen && (tiflags & TH_FIN) == 0)) { 1983 /* 1984 * Any valid FIN or RST must be to the left of the 1985 * window. At this point the FIN or RST must be a 1986 * duplicate or out of sequence; drop it. 1987 */ 1988 if (tiflags & TH_RST) 1989 goto drop; 1990 tiflags &= ~(TH_FIN|TH_RST); 1991 /* 1992 * Send an ACK to resynchronize and drop any data. 1993 * But keep on processing for RST or ACK. 1994 */ 1995 tp->t_flags |= TF_ACKNOW; 1996 todrop = tlen; 1997 dupseg = TRUE; 1998 tcpstat.tcps_rcvdupbyte += todrop; 1999 tcpstat.tcps_rcvduppack++; 2000 } else if ((tiflags & TH_RST) && 2001 th->th_seq != tp->last_ack_sent) { 2002 /* 2003 * Test for reset before adjusting the sequence 2004 * number for overlapping data. 2005 */ 2006 goto dropafterack_ratelim; 2007 } else { 2008 tcpstat.tcps_rcvpartduppack++; 2009 tcpstat.tcps_rcvpartdupbyte += todrop; 2010 } 2011 tcp_new_dsack(tp, th->th_seq, todrop); 2012 hdroptlen += todrop; /*drop from head afterwards*/ 2013 th->th_seq += todrop; 2014 tlen -= todrop; 2015 if (th->th_urp > todrop) 2016 th->th_urp -= todrop; 2017 else { 2018 tiflags &= ~TH_URG; 2019 th->th_urp = 0; 2020 } 2021 } 2022 2023 /* 2024 * If new data are received on a connection after the 2025 * user processes are gone, then RST the other end. 2026 */ 2027 if ((so->so_state & SS_NOFDREF) && 2028 tp->t_state > TCPS_CLOSE_WAIT && tlen) { 2029 tp = tcp_close(tp); 2030 tcpstat.tcps_rcvafterclose++; 2031 goto dropwithreset; 2032 } 2033 2034 /* 2035 * If segment ends after window, drop trailing data 2036 * (and PUSH and FIN); if nothing left, just ACK. 2037 */ 2038 todrop = (th->th_seq + tlen) - (tp->rcv_nxt+tp->rcv_wnd); 2039 if (todrop > 0) { 2040 tcpstat.tcps_rcvpackafterwin++; 2041 if (todrop >= tlen) { 2042 /* 2043 * The segment actually starts after the window. 2044 * th->th_seq + tlen - tp->rcv_nxt - tp->rcv_wnd >= tlen 2045 * th->th_seq - tp->rcv_nxt - tp->rcv_wnd >= 0 2046 * th->th_seq >= tp->rcv_nxt + tp->rcv_wnd 2047 */ 2048 tcpstat.tcps_rcvbyteafterwin += tlen; 2049 /* 2050 * If a new connection request is received 2051 * while in TIME_WAIT, drop the old connection 2052 * and start over if the sequence numbers 2053 * are above the previous ones. 2054 * 2055 * NOTE: We will checksum the packet again, and 2056 * so we need to put the header fields back into 2057 * network order! 2058 * XXX This kind of sucks, but we don't expect 2059 * XXX this to happen very often, so maybe it 2060 * XXX doesn't matter so much. 2061 */ 2062 if (tiflags & TH_SYN && 2063 tp->t_state == TCPS_TIME_WAIT && 2064 SEQ_GT(th->th_seq, tp->rcv_nxt)) { 2065 tp = tcp_close(tp); 2066 TCP_FIELDS_TO_NET(th); 2067 goto findpcb; 2068 } 2069 /* 2070 * If window is closed can only take segments at 2071 * window edge, and have to drop data and PUSH from 2072 * incoming segments. Continue processing, but 2073 * remember to ack. Otherwise, drop segment 2074 * and (if not RST) ack. 2075 */ 2076 if (tp->rcv_wnd == 0 && th->th_seq == tp->rcv_nxt) { 2077 tp->t_flags |= TF_ACKNOW; 2078 tcpstat.tcps_rcvwinprobe++; 2079 } else 2080 goto dropafterack; 2081 } else 2082 tcpstat.tcps_rcvbyteafterwin += todrop; 2083 m_adj(m, -todrop); 2084 tlen -= todrop; 2085 tiflags &= ~(TH_PUSH|TH_FIN); 2086 } 2087 2088 /* 2089 * If last ACK falls within this segment's sequence numbers, 2090 * and the timestamp is newer, record it. 2091 */ 2092 if (opti.ts_present && TSTMP_GEQ(opti.ts_val, tp->ts_recent) && 2093 SEQ_LEQ(th->th_seq, tp->last_ack_sent) && 2094 SEQ_LT(tp->last_ack_sent, th->th_seq + tlen + 2095 ((tiflags & (TH_SYN|TH_FIN)) != 0))) { 2096 tp->ts_recent_age = tcp_now; 2097 tp->ts_recent = opti.ts_val; 2098 } 2099 2100 /* 2101 * If the RST bit is set examine the state: 2102 * SYN_RECEIVED STATE: 2103 * If passive open, return to LISTEN state. 2104 * If active open, inform user that connection was refused. 2105 * ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES: 2106 * Inform user that connection was reset, and close tcb. 2107 * CLOSING, LAST_ACK, TIME_WAIT STATES 2108 * Close the tcb. 2109 */ 2110 if (tiflags & TH_RST) { 2111 if (th->th_seq != tp->last_ack_sent) 2112 goto dropafterack_ratelim; 2113 2114 switch (tp->t_state) { 2115 case TCPS_SYN_RECEIVED: 2116 so->so_error = ECONNREFUSED; 2117 goto close; 2118 2119 case TCPS_ESTABLISHED: 2120 case TCPS_FIN_WAIT_1: 2121 case TCPS_FIN_WAIT_2: 2122 case TCPS_CLOSE_WAIT: 2123 so->so_error = ECONNRESET; 2124 close: 2125 tp->t_state = TCPS_CLOSED; 2126 tcpstat.tcps_drops++; 2127 tp = tcp_close(tp); 2128 goto drop; 2129 2130 case TCPS_CLOSING: 2131 case TCPS_LAST_ACK: 2132 case TCPS_TIME_WAIT: 2133 tp = tcp_close(tp); 2134 goto drop; 2135 } 2136 } 2137 2138 /* 2139 * Since we've covered the SYN-SENT and SYN-RECEIVED states above 2140 * we must be in a synchronized state. RFC791 states (under RST 2141 * generation) that any unacceptable segment (an out-of-order SYN 2142 * qualifies) received in a synchronized state must elicit only an 2143 * empty acknowledgment segment ... and the connection remains in 2144 * the same state. 2145 */ 2146 if (tiflags & TH_SYN) { 2147 if (tp->rcv_nxt == th->th_seq) { 2148 tcp_respond(tp, m, m, th, (tcp_seq)0, th->th_ack - 1, 2149 TH_ACK); 2150 if (tcp_saveti) 2151 m_freem(tcp_saveti); 2152 return; 2153 } 2154 2155 goto dropafterack_ratelim; 2156 } 2157 2158 /* 2159 * If the ACK bit is off we drop the segment and return. 2160 */ 2161 if ((tiflags & TH_ACK) == 0) { 2162 if (tp->t_flags & TF_ACKNOW) 2163 goto dropafterack; 2164 else 2165 goto drop; 2166 } 2167 2168 /* 2169 * Ack processing. 2170 */ 2171 switch (tp->t_state) { 2172 2173 /* 2174 * In SYN_RECEIVED state if the ack ACKs our SYN then enter 2175 * ESTABLISHED state and continue processing, otherwise 2176 * send an RST. 2177 */ 2178 case TCPS_SYN_RECEIVED: 2179 if (SEQ_GT(tp->snd_una, th->th_ack) || 2180 SEQ_GT(th->th_ack, tp->snd_max)) 2181 goto dropwithreset; 2182 tcpstat.tcps_connects++; 2183 soisconnected(so); 2184 tcp_established(tp); 2185 /* Do window scaling? */ 2186 if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == 2187 (TF_RCVD_SCALE|TF_REQ_SCALE)) { 2188 tp->snd_scale = tp->requested_s_scale; 2189 tp->rcv_scale = tp->request_r_scale; 2190 } 2191 TCP_REASS_LOCK(tp); 2192 (void) tcp_reass(tp, NULL, (struct mbuf *)0, &tlen); 2193 TCP_REASS_UNLOCK(tp); 2194 tp->snd_wl1 = th->th_seq - 1; 2195 /* fall into ... */ 2196 2197 /* 2198 * In ESTABLISHED state: drop duplicate ACKs; ACK out of range 2199 * ACKs. If the ack is in the range 2200 * tp->snd_una < th->th_ack <= tp->snd_max 2201 * then advance tp->snd_una to th->th_ack and drop 2202 * data from the retransmission queue. If this ACK reflects 2203 * more up to date window information we update our window information. 2204 */ 2205 case TCPS_ESTABLISHED: 2206 case TCPS_FIN_WAIT_1: 2207 case TCPS_FIN_WAIT_2: 2208 case TCPS_CLOSE_WAIT: 2209 case TCPS_CLOSING: 2210 case TCPS_LAST_ACK: 2211 case TCPS_TIME_WAIT: 2212 2213 if (SEQ_LEQ(th->th_ack, tp->snd_una)) { 2214 if (tlen == 0 && !dupseg && tiwin == tp->snd_wnd) { 2215 tcpstat.tcps_rcvdupack++; 2216 /* 2217 * If we have outstanding data (other than 2218 * a window probe), this is a completely 2219 * duplicate ack (ie, window info didn't 2220 * change), the ack is the biggest we've 2221 * seen and we've seen exactly our rexmt 2222 * threshhold of them, assume a packet 2223 * has been dropped and retransmit it. 2224 * Kludge snd_nxt & the congestion 2225 * window so we send only this one 2226 * packet. 2227 * 2228 * We know we're losing at the current 2229 * window size so do congestion avoidance 2230 * (set ssthresh to half the current window 2231 * and pull our congestion window back to 2232 * the new ssthresh). 2233 * 2234 * Dup acks mean that packets have left the 2235 * network (they're now cached at the receiver) 2236 * so bump cwnd by the amount in the receiver 2237 * to keep a constant cwnd packets in the 2238 * network. 2239 * 2240 * When using TCP ECN, notify the peer that 2241 * we reduced the cwnd. 2242 * 2243 * If we are using TCP/SACK, then enter 2244 * Fast Recovery if the receiver SACKs 2245 * data that is tcprexmtthresh * MSS 2246 * bytes past the last ACKed segment, 2247 * irrespective of the number of DupAcks. 2248 */ 2249 if (TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0 || 2250 th->th_ack != tp->snd_una) 2251 tp->t_dupacks = 0; 2252 else if (tp->t_partialacks < 0 && 2253 (++tp->t_dupacks == tcprexmtthresh || 2254 TCP_FACK_FASTRECOV(tp))) { 2255 /* 2256 * Do the fast retransmit, and adjust 2257 * congestion control paramenters. 2258 */ 2259 if (tp->t_congctl->fast_retransmit(tp, th)) { 2260 /* False fast retransmit */ 2261 break; 2262 } else 2263 goto drop; 2264 } else if (tp->t_dupacks > tcprexmtthresh) { 2265 tp->snd_cwnd += tp->t_segsz; 2266 (void) tcp_output(tp); 2267 goto drop; 2268 } 2269 } else { 2270 /* 2271 * If the ack appears to be very old, only 2272 * allow data that is in-sequence. This 2273 * makes it somewhat more difficult to insert 2274 * forged data by guessing sequence numbers. 2275 * Sent an ack to try to update the send 2276 * sequence number on the other side. 2277 */ 2278 if (tlen && th->th_seq != tp->rcv_nxt && 2279 SEQ_LT(th->th_ack, 2280 tp->snd_una - tp->max_sndwnd)) 2281 goto dropafterack; 2282 } 2283 break; 2284 } 2285 /* 2286 * If the congestion window was inflated to account 2287 * for the other side's cached packets, retract it. 2288 */ 2289 /* XXX: make SACK have his own congestion control 2290 * struct -- rpaulo */ 2291 if (TCP_SACK_ENABLED(tp)) 2292 tcp_sack_newack(tp, th); 2293 else 2294 tp->t_congctl->fast_retransmit_newack(tp, th); 2295 if (SEQ_GT(th->th_ack, tp->snd_max)) { 2296 tcpstat.tcps_rcvacktoomuch++; 2297 goto dropafterack; 2298 } 2299 acked = th->th_ack - tp->snd_una; 2300 tcpstat.tcps_rcvackpack++; 2301 tcpstat.tcps_rcvackbyte += acked; 2302 2303 /* 2304 * If we have a timestamp reply, update smoothed 2305 * round trip time. If no timestamp is present but 2306 * transmit timer is running and timed sequence 2307 * number was acked, update smoothed round trip time. 2308 * Since we now have an rtt measurement, cancel the 2309 * timer backoff (cf., Phil Karn's retransmit alg.). 2310 * Recompute the initial retransmit timer. 2311 */ 2312 if (ts_rtt) 2313 tcp_xmit_timer(tp, ts_rtt); 2314 else if (tp->t_rtttime && SEQ_GT(th->th_ack, tp->t_rtseq)) 2315 tcp_xmit_timer(tp, tcp_now - tp->t_rtttime); 2316 2317 /* 2318 * If all outstanding data is acked, stop retransmit 2319 * timer and remember to restart (more output or persist). 2320 * If there is more data to be acked, restart retransmit 2321 * timer, using current (possibly backed-off) value. 2322 */ 2323 if (th->th_ack == tp->snd_max) { 2324 TCP_TIMER_DISARM(tp, TCPT_REXMT); 2325 needoutput = 1; 2326 } else if (TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) 2327 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 2328 2329 /* 2330 * New data has been acked, adjust the congestion window. 2331 */ 2332 tp->t_congctl->newack(tp, th); 2333 2334 ND6_HINT(tp); 2335 if (acked > so->so_snd.sb_cc) { 2336 tp->snd_wnd -= so->so_snd.sb_cc; 2337 sbdrop(&so->so_snd, (int)so->so_snd.sb_cc); 2338 ourfinisacked = 1; 2339 } else { 2340 if (acked > (tp->t_lastoff - tp->t_inoff)) 2341 tp->t_lastm = NULL; 2342 sbdrop(&so->so_snd, acked); 2343 tp->t_lastoff -= acked; 2344 tp->snd_wnd -= acked; 2345 ourfinisacked = 0; 2346 } 2347 sowwakeup(so); 2348 2349 ICMP_CHECK(tp, th, acked); 2350 2351 tp->snd_una = th->th_ack; 2352 if (SEQ_GT(tp->snd_una, tp->snd_fack)) 2353 tp->snd_fack = tp->snd_una; 2354 if (SEQ_LT(tp->snd_nxt, tp->snd_una)) 2355 tp->snd_nxt = tp->snd_una; 2356 if (SEQ_LT(tp->snd_high, tp->snd_una)) 2357 tp->snd_high = tp->snd_una; 2358 2359 switch (tp->t_state) { 2360 2361 /* 2362 * In FIN_WAIT_1 STATE in addition to the processing 2363 * for the ESTABLISHED state if our FIN is now acknowledged 2364 * then enter FIN_WAIT_2. 2365 */ 2366 case TCPS_FIN_WAIT_1: 2367 if (ourfinisacked) { 2368 /* 2369 * If we can't receive any more 2370 * data, then closing user can proceed. 2371 * Starting the timer is contrary to the 2372 * specification, but if we don't get a FIN 2373 * we'll hang forever. 2374 */ 2375 if (so->so_state & SS_CANTRCVMORE) { 2376 soisdisconnected(so); 2377 if (tcp_maxidle > 0) 2378 TCP_TIMER_ARM(tp, TCPT_2MSL, 2379 tcp_maxidle); 2380 } 2381 tp->t_state = TCPS_FIN_WAIT_2; 2382 } 2383 break; 2384 2385 /* 2386 * In CLOSING STATE in addition to the processing for 2387 * the ESTABLISHED state if the ACK acknowledges our FIN 2388 * then enter the TIME-WAIT state, otherwise ignore 2389 * the segment. 2390 */ 2391 case TCPS_CLOSING: 2392 if (ourfinisacked) { 2393 tp->t_state = TCPS_TIME_WAIT; 2394 tcp_canceltimers(tp); 2395 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2396 soisdisconnected(so); 2397 } 2398 break; 2399 2400 /* 2401 * In LAST_ACK, we may still be waiting for data to drain 2402 * and/or to be acked, as well as for the ack of our FIN. 2403 * If our FIN is now acknowledged, delete the TCB, 2404 * enter the closed state and return. 2405 */ 2406 case TCPS_LAST_ACK: 2407 if (ourfinisacked) { 2408 tp = tcp_close(tp); 2409 goto drop; 2410 } 2411 break; 2412 2413 /* 2414 * In TIME_WAIT state the only thing that should arrive 2415 * is a retransmission of the remote FIN. Acknowledge 2416 * it and restart the finack timer. 2417 */ 2418 case TCPS_TIME_WAIT: 2419 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2420 goto dropafterack; 2421 } 2422 } 2423 2424 step6: 2425 /* 2426 * Update window information. 2427 * Don't look at window if no ACK: TAC's send garbage on first SYN. 2428 */ 2429 if ((tiflags & TH_ACK) && (SEQ_LT(tp->snd_wl1, th->th_seq) || 2430 (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) || 2431 (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) { 2432 /* keep track of pure window updates */ 2433 if (tlen == 0 && 2434 tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd) 2435 tcpstat.tcps_rcvwinupd++; 2436 tp->snd_wnd = tiwin; 2437 tp->snd_wl1 = th->th_seq; 2438 tp->snd_wl2 = th->th_ack; 2439 if (tp->snd_wnd > tp->max_sndwnd) 2440 tp->max_sndwnd = tp->snd_wnd; 2441 needoutput = 1; 2442 } 2443 2444 /* 2445 * Process segments with URG. 2446 */ 2447 if ((tiflags & TH_URG) && th->th_urp && 2448 TCPS_HAVERCVDFIN(tp->t_state) == 0) { 2449 /* 2450 * This is a kludge, but if we receive and accept 2451 * random urgent pointers, we'll crash in 2452 * soreceive. It's hard to imagine someone 2453 * actually wanting to send this much urgent data. 2454 */ 2455 if (th->th_urp + so->so_rcv.sb_cc > sb_max) { 2456 th->th_urp = 0; /* XXX */ 2457 tiflags &= ~TH_URG; /* XXX */ 2458 goto dodata; /* XXX */ 2459 } 2460 /* 2461 * If this segment advances the known urgent pointer, 2462 * then mark the data stream. This should not happen 2463 * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since 2464 * a FIN has been received from the remote side. 2465 * In these states we ignore the URG. 2466 * 2467 * According to RFC961 (Assigned Protocols), 2468 * the urgent pointer points to the last octet 2469 * of urgent data. We continue, however, 2470 * to consider it to indicate the first octet 2471 * of data past the urgent section as the original 2472 * spec states (in one of two places). 2473 */ 2474 if (SEQ_GT(th->th_seq+th->th_urp, tp->rcv_up)) { 2475 tp->rcv_up = th->th_seq + th->th_urp; 2476 so->so_oobmark = so->so_rcv.sb_cc + 2477 (tp->rcv_up - tp->rcv_nxt) - 1; 2478 if (so->so_oobmark == 0) 2479 so->so_state |= SS_RCVATMARK; 2480 sohasoutofband(so); 2481 tp->t_oobflags &= ~(TCPOOB_HAVEDATA | TCPOOB_HADDATA); 2482 } 2483 /* 2484 * Remove out of band data so doesn't get presented to user. 2485 * This can happen independent of advancing the URG pointer, 2486 * but if two URG's are pending at once, some out-of-band 2487 * data may creep in... ick. 2488 */ 2489 if (th->th_urp <= (u_int16_t) tlen 2490 #ifdef SO_OOBINLINE 2491 && (so->so_options & SO_OOBINLINE) == 0 2492 #endif 2493 ) 2494 tcp_pulloutofband(so, th, m, hdroptlen); 2495 } else 2496 /* 2497 * If no out of band data is expected, 2498 * pull receive urgent pointer along 2499 * with the receive window. 2500 */ 2501 if (SEQ_GT(tp->rcv_nxt, tp->rcv_up)) 2502 tp->rcv_up = tp->rcv_nxt; 2503 dodata: /* XXX */ 2504 2505 /* 2506 * Process the segment text, merging it into the TCP sequencing queue, 2507 * and arranging for acknowledgement of receipt if necessary. 2508 * This process logically involves adjusting tp->rcv_wnd as data 2509 * is presented to the user (this happens in tcp_usrreq.c, 2510 * case PRU_RCVD). If a FIN has already been received on this 2511 * connection then we just ignore the text. 2512 */ 2513 if ((tlen || (tiflags & TH_FIN)) && 2514 TCPS_HAVERCVDFIN(tp->t_state) == 0) { 2515 /* 2516 * Insert segment ti into reassembly queue of tcp with 2517 * control block tp. Return TH_FIN if reassembly now includes 2518 * a segment with FIN. The macro form does the common case 2519 * inline (segment is the next to be received on an 2520 * established connection, and the queue is empty), 2521 * avoiding linkage into and removal from the queue and 2522 * repetition of various conversions. 2523 * Set DELACK for segments received in order, but ack 2524 * immediately when segments are out of order 2525 * (so fast retransmit can work). 2526 */ 2527 /* NOTE: this was TCP_REASS() macro, but used only once */ 2528 TCP_REASS_LOCK(tp); 2529 if (th->th_seq == tp->rcv_nxt && 2530 TAILQ_FIRST(&tp->segq) == NULL && 2531 tp->t_state == TCPS_ESTABLISHED) { 2532 TCP_SETUP_ACK(tp, th); 2533 tp->rcv_nxt += tlen; 2534 tiflags = th->th_flags & TH_FIN; 2535 tcpstat.tcps_rcvpack++; 2536 tcpstat.tcps_rcvbyte += tlen; 2537 ND6_HINT(tp); 2538 if (so->so_state & SS_CANTRCVMORE) 2539 m_freem(m); 2540 else { 2541 m_adj(m, hdroptlen); 2542 sbappendstream(&(so)->so_rcv, m); 2543 } 2544 sorwakeup(so); 2545 } else { 2546 m_adj(m, hdroptlen); 2547 tiflags = tcp_reass(tp, th, m, &tlen); 2548 tp->t_flags |= TF_ACKNOW; 2549 } 2550 TCP_REASS_UNLOCK(tp); 2551 2552 /* 2553 * Note the amount of data that peer has sent into 2554 * our window, in order to estimate the sender's 2555 * buffer size. 2556 */ 2557 len = so->so_rcv.sb_hiwat - (tp->rcv_adv - tp->rcv_nxt); 2558 } else { 2559 m_freem(m); 2560 m = NULL; 2561 tiflags &= ~TH_FIN; 2562 } 2563 2564 /* 2565 * If FIN is received ACK the FIN and let the user know 2566 * that the connection is closing. Ignore a FIN received before 2567 * the connection is fully established. 2568 */ 2569 if ((tiflags & TH_FIN) && TCPS_HAVEESTABLISHED(tp->t_state)) { 2570 if (TCPS_HAVERCVDFIN(tp->t_state) == 0) { 2571 socantrcvmore(so); 2572 tp->t_flags |= TF_ACKNOW; 2573 tp->rcv_nxt++; 2574 } 2575 switch (tp->t_state) { 2576 2577 /* 2578 * In ESTABLISHED STATE enter the CLOSE_WAIT state. 2579 */ 2580 case TCPS_ESTABLISHED: 2581 tp->t_state = TCPS_CLOSE_WAIT; 2582 break; 2583 2584 /* 2585 * If still in FIN_WAIT_1 STATE FIN has not been acked so 2586 * enter the CLOSING state. 2587 */ 2588 case TCPS_FIN_WAIT_1: 2589 tp->t_state = TCPS_CLOSING; 2590 break; 2591 2592 /* 2593 * In FIN_WAIT_2 state enter the TIME_WAIT state, 2594 * starting the time-wait timer, turning off the other 2595 * standard timers. 2596 */ 2597 case TCPS_FIN_WAIT_2: 2598 tp->t_state = TCPS_TIME_WAIT; 2599 tcp_canceltimers(tp); 2600 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2601 soisdisconnected(so); 2602 break; 2603 2604 /* 2605 * In TIME_WAIT state restart the 2 MSL time_wait timer. 2606 */ 2607 case TCPS_TIME_WAIT: 2608 TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * TCPTV_MSL); 2609 break; 2610 } 2611 } 2612 #ifdef TCP_DEBUG 2613 if (so->so_options & SO_DEBUG) 2614 tcp_trace(TA_INPUT, ostate, tp, tcp_saveti, 0); 2615 #endif 2616 2617 /* 2618 * Return any desired output. 2619 */ 2620 if (needoutput || (tp->t_flags & TF_ACKNOW)) { 2621 (void) tcp_output(tp); 2622 } 2623 if (tcp_saveti) 2624 m_freem(tcp_saveti); 2625 return; 2626 2627 badsyn: 2628 /* 2629 * Received a bad SYN. Increment counters and dropwithreset. 2630 */ 2631 tcpstat.tcps_badsyn++; 2632 tp = NULL; 2633 goto dropwithreset; 2634 2635 dropafterack: 2636 /* 2637 * Generate an ACK dropping incoming segment if it occupies 2638 * sequence space, where the ACK reflects our state. 2639 */ 2640 if (tiflags & TH_RST) 2641 goto drop; 2642 goto dropafterack2; 2643 2644 dropafterack_ratelim: 2645 /* 2646 * We may want to rate-limit ACKs against SYN/RST attack. 2647 */ 2648 if (ppsratecheck(&tcp_ackdrop_ppslim_last, &tcp_ackdrop_ppslim_count, 2649 tcp_ackdrop_ppslim) == 0) { 2650 /* XXX stat */ 2651 goto drop; 2652 } 2653 /* ...fall into dropafterack2... */ 2654 2655 dropafterack2: 2656 m_freem(m); 2657 tp->t_flags |= TF_ACKNOW; 2658 (void) tcp_output(tp); 2659 if (tcp_saveti) 2660 m_freem(tcp_saveti); 2661 return; 2662 2663 dropwithreset_ratelim: 2664 /* 2665 * We may want to rate-limit RSTs in certain situations, 2666 * particularly if we are sending an RST in response to 2667 * an attempt to connect to or otherwise communicate with 2668 * a port for which we have no socket. 2669 */ 2670 if (ppsratecheck(&tcp_rst_ppslim_last, &tcp_rst_ppslim_count, 2671 tcp_rst_ppslim) == 0) { 2672 /* XXX stat */ 2673 goto drop; 2674 } 2675 /* ...fall into dropwithreset... */ 2676 2677 dropwithreset: 2678 /* 2679 * Generate a RST, dropping incoming segment. 2680 * Make ACK acceptable to originator of segment. 2681 */ 2682 if (tiflags & TH_RST) 2683 goto drop; 2684 2685 switch (af) { 2686 #ifdef INET6 2687 case AF_INET6: 2688 /* For following calls to tcp_respond */ 2689 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) 2690 goto drop; 2691 break; 2692 #endif /* INET6 */ 2693 case AF_INET: 2694 if (IN_MULTICAST(ip->ip_dst.s_addr) || 2695 in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) 2696 goto drop; 2697 } 2698 2699 if (tiflags & TH_ACK) 2700 (void)tcp_respond(tp, m, m, th, (tcp_seq)0, th->th_ack, TH_RST); 2701 else { 2702 if (tiflags & TH_SYN) 2703 tlen++; 2704 (void)tcp_respond(tp, m, m, th, th->th_seq + tlen, (tcp_seq)0, 2705 TH_RST|TH_ACK); 2706 } 2707 if (tcp_saveti) 2708 m_freem(tcp_saveti); 2709 return; 2710 2711 badcsum: 2712 drop: 2713 /* 2714 * Drop space held by incoming segment and return. 2715 */ 2716 if (tp) { 2717 if (tp->t_inpcb) 2718 so = tp->t_inpcb->inp_socket; 2719 #ifdef INET6 2720 else if (tp->t_in6pcb) 2721 so = tp->t_in6pcb->in6p_socket; 2722 #endif 2723 else 2724 so = NULL; 2725 #ifdef TCP_DEBUG 2726 if (so && (so->so_options & SO_DEBUG) != 0) 2727 tcp_trace(TA_DROP, ostate, tp, tcp_saveti, 0); 2728 #endif 2729 } 2730 if (tcp_saveti) 2731 m_freem(tcp_saveti); 2732 m_freem(m); 2733 return; 2734 } 2735 2736 #ifdef TCP_SIGNATURE 2737 int 2738 tcp_signature_apply(void *fstate, caddr_t data, u_int len) 2739 { 2740 2741 MD5Update(fstate, (u_char *)data, len); 2742 return (0); 2743 } 2744 2745 struct secasvar * 2746 tcp_signature_getsav(struct mbuf *m, struct tcphdr *th) 2747 { 2748 struct secasvar *sav; 2749 #ifdef FAST_IPSEC 2750 union sockaddr_union dst; 2751 #endif 2752 struct ip *ip; 2753 struct ip6_hdr *ip6; 2754 2755 ip = mtod(m, struct ip *); 2756 switch (ip->ip_v) { 2757 case 4: 2758 ip = mtod(m, struct ip *); 2759 ip6 = NULL; 2760 break; 2761 case 6: 2762 ip = NULL; 2763 ip6 = mtod(m, struct ip6_hdr *); 2764 break; 2765 default: 2766 return (NULL); 2767 } 2768 2769 #ifdef FAST_IPSEC 2770 /* Extract the destination from the IP header in the mbuf. */ 2771 bzero(&dst, sizeof(union sockaddr_union)); 2772 dst.sa.sa_len = sizeof(struct sockaddr_in); 2773 dst.sa.sa_family = AF_INET; 2774 dst.sin.sin_addr = ip->ip_dst; 2775 2776 /* 2777 * Look up an SADB entry which matches the address of the peer. 2778 */ 2779 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2780 #else 2781 if (ip) 2782 sav = key_allocsa(AF_INET, (caddr_t)&ip->ip_src, 2783 (caddr_t)&ip->ip_dst, IPPROTO_TCP, 2784 htonl(TCP_SIG_SPI), 0, 0); 2785 else 2786 sav = key_allocsa(AF_INET6, (caddr_t)&ip6->ip6_src, 2787 (caddr_t)&ip6->ip6_dst, IPPROTO_TCP, 2788 htonl(TCP_SIG_SPI), 0, 0); 2789 #endif 2790 2791 return (sav); /* freesav must be performed by caller */ 2792 } 2793 2794 int 2795 tcp_signature(struct mbuf *m, struct tcphdr *th, int thoff, 2796 struct secasvar *sav, char *sig) 2797 { 2798 MD5_CTX ctx; 2799 struct ip *ip; 2800 struct ipovly *ipovly; 2801 struct ip6_hdr *ip6; 2802 struct ippseudo ippseudo; 2803 struct ip6_hdr_pseudo ip6pseudo; 2804 struct tcphdr th0; 2805 int l, tcphdrlen; 2806 2807 if (sav == NULL) 2808 return (-1); 2809 2810 tcphdrlen = th->th_off * 4; 2811 2812 switch (mtod(m, struct ip *)->ip_v) { 2813 case 4: 2814 ip = mtod(m, struct ip *); 2815 ip6 = NULL; 2816 break; 2817 case 6: 2818 ip = NULL; 2819 ip6 = mtod(m, struct ip6_hdr *); 2820 break; 2821 default: 2822 return (-1); 2823 } 2824 2825 MD5Init(&ctx); 2826 2827 if (ip) { 2828 memset(&ippseudo, 0, sizeof(ippseudo)); 2829 ipovly = (struct ipovly *)ip; 2830 ippseudo.ippseudo_src = ipovly->ih_src; 2831 ippseudo.ippseudo_dst = ipovly->ih_dst; 2832 ippseudo.ippseudo_pad = 0; 2833 ippseudo.ippseudo_p = IPPROTO_TCP; 2834 ippseudo.ippseudo_len = htons(m->m_pkthdr.len - thoff); 2835 MD5Update(&ctx, (char *)&ippseudo, sizeof(ippseudo)); 2836 } else { 2837 memset(&ip6pseudo, 0, sizeof(ip6pseudo)); 2838 ip6pseudo.ip6ph_src = ip6->ip6_src; 2839 in6_clearscope(&ip6pseudo.ip6ph_src); 2840 ip6pseudo.ip6ph_dst = ip6->ip6_dst; 2841 in6_clearscope(&ip6pseudo.ip6ph_dst); 2842 ip6pseudo.ip6ph_len = htons(m->m_pkthdr.len - thoff); 2843 ip6pseudo.ip6ph_nxt = IPPROTO_TCP; 2844 MD5Update(&ctx, (char *)&ip6pseudo, sizeof(ip6pseudo)); 2845 } 2846 2847 th0 = *th; 2848 th0.th_sum = 0; 2849 MD5Update(&ctx, (char *)&th0, sizeof(th0)); 2850 2851 l = m->m_pkthdr.len - thoff - tcphdrlen; 2852 if (l > 0) 2853 m_apply(m, thoff + tcphdrlen, 2854 m->m_pkthdr.len - thoff - tcphdrlen, 2855 tcp_signature_apply, &ctx); 2856 2857 MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); 2858 MD5Final(sig, &ctx); 2859 2860 return (0); 2861 } 2862 #endif 2863 2864 int 2865 tcp_dooptions(struct tcpcb *tp, u_char *cp, int cnt, struct tcphdr *th, 2866 struct mbuf *m __unused, int toff __unused, struct tcp_opt_info *oi) 2867 { 2868 u_int16_t mss; 2869 int opt, optlen = 0; 2870 #ifdef TCP_SIGNATURE 2871 caddr_t sigp = NULL; 2872 char sigbuf[TCP_SIGLEN]; 2873 struct secasvar *sav = NULL; 2874 #endif 2875 2876 for (; cp && cnt > 0; cnt -= optlen, cp += optlen) { 2877 opt = cp[0]; 2878 if (opt == TCPOPT_EOL) 2879 break; 2880 if (opt == TCPOPT_NOP) 2881 optlen = 1; 2882 else { 2883 if (cnt < 2) 2884 break; 2885 optlen = cp[1]; 2886 if (optlen < 2 || optlen > cnt) 2887 break; 2888 } 2889 switch (opt) { 2890 2891 default: 2892 continue; 2893 2894 case TCPOPT_MAXSEG: 2895 if (optlen != TCPOLEN_MAXSEG) 2896 continue; 2897 if (!(th->th_flags & TH_SYN)) 2898 continue; 2899 if (TCPS_HAVERCVDSYN(tp->t_state)) 2900 continue; 2901 bcopy(cp + 2, &mss, sizeof(mss)); 2902 oi->maxseg = ntohs(mss); 2903 break; 2904 2905 case TCPOPT_WINDOW: 2906 if (optlen != TCPOLEN_WINDOW) 2907 continue; 2908 if (!(th->th_flags & TH_SYN)) 2909 continue; 2910 if (TCPS_HAVERCVDSYN(tp->t_state)) 2911 continue; 2912 tp->t_flags |= TF_RCVD_SCALE; 2913 tp->requested_s_scale = cp[2]; 2914 if (tp->requested_s_scale > TCP_MAX_WINSHIFT) { 2915 #if 0 /*XXX*/ 2916 char *p; 2917 2918 if (ip) 2919 p = ntohl(ip->ip_src); 2920 #ifdef INET6 2921 else if (ip6) 2922 p = ip6_sprintf(&ip6->ip6_src); 2923 #endif 2924 else 2925 p = "(unknown)"; 2926 log(LOG_ERR, "TCP: invalid wscale %d from %s, " 2927 "assuming %d\n", 2928 tp->requested_s_scale, p, 2929 TCP_MAX_WINSHIFT); 2930 #else 2931 log(LOG_ERR, "TCP: invalid wscale %d, " 2932 "assuming %d\n", 2933 tp->requested_s_scale, 2934 TCP_MAX_WINSHIFT); 2935 #endif 2936 tp->requested_s_scale = TCP_MAX_WINSHIFT; 2937 } 2938 break; 2939 2940 case TCPOPT_TIMESTAMP: 2941 if (optlen != TCPOLEN_TIMESTAMP) 2942 continue; 2943 oi->ts_present = 1; 2944 bcopy(cp + 2, &oi->ts_val, sizeof(oi->ts_val)); 2945 NTOHL(oi->ts_val); 2946 bcopy(cp + 6, &oi->ts_ecr, sizeof(oi->ts_ecr)); 2947 NTOHL(oi->ts_ecr); 2948 2949 if (!(th->th_flags & TH_SYN)) 2950 continue; 2951 if (TCPS_HAVERCVDSYN(tp->t_state)) 2952 continue; 2953 /* 2954 * A timestamp received in a SYN makes 2955 * it ok to send timestamp requests and replies. 2956 */ 2957 tp->t_flags |= TF_RCVD_TSTMP; 2958 tp->ts_recent = oi->ts_val; 2959 tp->ts_recent_age = tcp_now; 2960 break; 2961 2962 case TCPOPT_SACK_PERMITTED: 2963 if (optlen != TCPOLEN_SACK_PERMITTED) 2964 continue; 2965 if (!(th->th_flags & TH_SYN)) 2966 continue; 2967 if (TCPS_HAVERCVDSYN(tp->t_state)) 2968 continue; 2969 if (tcp_do_sack) { 2970 tp->t_flags |= TF_SACK_PERMIT; 2971 tp->t_flags |= TF_WILL_SACK; 2972 } 2973 break; 2974 2975 case TCPOPT_SACK: 2976 tcp_sack_option(tp, th, cp, optlen); 2977 break; 2978 #ifdef TCP_SIGNATURE 2979 case TCPOPT_SIGNATURE: 2980 if (optlen != TCPOLEN_SIGNATURE) 2981 continue; 2982 if (sigp && bcmp(sigp, cp + 2, TCP_SIGLEN)) 2983 return (-1); 2984 2985 sigp = sigbuf; 2986 memcpy(sigbuf, cp + 2, TCP_SIGLEN); 2987 memset(cp + 2, 0, TCP_SIGLEN); 2988 tp->t_flags |= TF_SIGNATURE; 2989 break; 2990 #endif 2991 } 2992 } 2993 2994 #ifdef TCP_SIGNATURE 2995 if (tp->t_flags & TF_SIGNATURE) { 2996 2997 sav = tcp_signature_getsav(m, th); 2998 2999 if (sav == NULL && tp->t_state == TCPS_LISTEN) 3000 return (-1); 3001 } 3002 3003 if ((sigp ? TF_SIGNATURE : 0) ^ (tp->t_flags & TF_SIGNATURE)) { 3004 if (sav == NULL) 3005 return (-1); 3006 #ifdef FAST_IPSEC 3007 KEY_FREESAV(&sav); 3008 #else 3009 key_freesav(sav); 3010 #endif 3011 return (-1); 3012 } 3013 3014 if (sigp) { 3015 char sig[TCP_SIGLEN]; 3016 3017 TCP_FIELDS_TO_NET(th); 3018 if (tcp_signature(m, th, toff, sav, sig) < 0) { 3019 TCP_FIELDS_TO_HOST(th); 3020 if (sav == NULL) 3021 return (-1); 3022 #ifdef FAST_IPSEC 3023 KEY_FREESAV(&sav); 3024 #else 3025 key_freesav(sav); 3026 #endif 3027 return (-1); 3028 } 3029 TCP_FIELDS_TO_HOST(th); 3030 3031 if (bcmp(sig, sigp, TCP_SIGLEN)) { 3032 tcpstat.tcps_badsig++; 3033 if (sav == NULL) 3034 return (-1); 3035 #ifdef FAST_IPSEC 3036 KEY_FREESAV(&sav); 3037 #else 3038 key_freesav(sav); 3039 #endif 3040 return (-1); 3041 } else 3042 tcpstat.tcps_goodsig++; 3043 3044 key_sa_recordxfer(sav, m); 3045 #ifdef FAST_IPSEC 3046 KEY_FREESAV(&sav); 3047 #else 3048 key_freesav(sav); 3049 #endif 3050 } 3051 #endif 3052 3053 return (0); 3054 } 3055 3056 /* 3057 * Pull out of band byte out of a segment so 3058 * it doesn't appear in the user's data queue. 3059 * It is still reflected in the segment length for 3060 * sequencing purposes. 3061 */ 3062 void 3063 tcp_pulloutofband(struct socket *so, struct tcphdr *th, 3064 struct mbuf *m, int off) 3065 { 3066 int cnt = off + th->th_urp - 1; 3067 3068 while (cnt >= 0) { 3069 if (m->m_len > cnt) { 3070 char *cp = mtod(m, caddr_t) + cnt; 3071 struct tcpcb *tp = sototcpcb(so); 3072 3073 tp->t_iobc = *cp; 3074 tp->t_oobflags |= TCPOOB_HAVEDATA; 3075 bcopy(cp+1, cp, (unsigned)(m->m_len - cnt - 1)); 3076 m->m_len--; 3077 return; 3078 } 3079 cnt -= m->m_len; 3080 m = m->m_next; 3081 if (m == 0) 3082 break; 3083 } 3084 panic("tcp_pulloutofband"); 3085 } 3086 3087 /* 3088 * Collect new round-trip time estimate 3089 * and update averages and current timeout. 3090 */ 3091 void 3092 tcp_xmit_timer(struct tcpcb *tp, uint32_t rtt) 3093 { 3094 int32_t delta; 3095 3096 tcpstat.tcps_rttupdated++; 3097 if (tp->t_srtt != 0) { 3098 /* 3099 * srtt is stored as fixed point with 3 bits after the 3100 * binary point (i.e., scaled by 8). The following magic 3101 * is equivalent to the smoothing algorithm in rfc793 with 3102 * an alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed 3103 * point). Adjust rtt to origin 0. 3104 */ 3105 delta = (rtt << 2) - (tp->t_srtt >> TCP_RTT_SHIFT); 3106 if ((tp->t_srtt += delta) <= 0) 3107 tp->t_srtt = 1 << 2; 3108 /* 3109 * We accumulate a smoothed rtt variance (actually, a 3110 * smoothed mean difference), then set the retransmit 3111 * timer to smoothed rtt + 4 times the smoothed variance. 3112 * rttvar is stored as fixed point with 2 bits after the 3113 * binary point (scaled by 4). The following is 3114 * equivalent to rfc793 smoothing with an alpha of .75 3115 * (rttvar = rttvar*3/4 + |delta| / 4). This replaces 3116 * rfc793's wired-in beta. 3117 */ 3118 if (delta < 0) 3119 delta = -delta; 3120 delta -= (tp->t_rttvar >> TCP_RTTVAR_SHIFT); 3121 if ((tp->t_rttvar += delta) <= 0) 3122 tp->t_rttvar = 1 << 2; 3123 } else { 3124 /* 3125 * No rtt measurement yet - use the unsmoothed rtt. 3126 * Set the variance to half the rtt (so our first 3127 * retransmit happens at 3*rtt). 3128 */ 3129 tp->t_srtt = rtt << (TCP_RTT_SHIFT + 2); 3130 tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT + 2 - 1); 3131 } 3132 tp->t_rtttime = 0; 3133 tp->t_rxtshift = 0; 3134 3135 /* 3136 * the retransmit should happen at rtt + 4 * rttvar. 3137 * Because of the way we do the smoothing, srtt and rttvar 3138 * will each average +1/2 tick of bias. When we compute 3139 * the retransmit timer, we want 1/2 tick of rounding and 3140 * 1 extra tick because of +-1/2 tick uncertainty in the 3141 * firing of the timer. The bias will give us exactly the 3142 * 1.5 tick we need. But, because the bias is 3143 * statistical, we have to test that we don't drop below 3144 * the minimum feasible timer (which is 2 ticks). 3145 */ 3146 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), 3147 max(tp->t_rttmin, rtt + 2), TCPTV_REXMTMAX); 3148 3149 /* 3150 * We received an ack for a packet that wasn't retransmitted; 3151 * it is probably safe to discard any error indications we've 3152 * received recently. This isn't quite right, but close enough 3153 * for now (a route might have failed after we sent a segment, 3154 * and the return path might not be symmetrical). 3155 */ 3156 tp->t_softerror = 0; 3157 } 3158 3159 3160 /* 3161 * TCP compressed state engine. Currently used to hold compressed 3162 * state for SYN_RECEIVED. 3163 */ 3164 3165 u_long syn_cache_count; 3166 u_int32_t syn_hash1, syn_hash2; 3167 3168 #define SYN_HASH(sa, sp, dp) \ 3169 ((((sa)->s_addr^syn_hash1)*(((((u_int32_t)(dp))<<16) + \ 3170 ((u_int32_t)(sp)))^syn_hash2))) 3171 #ifndef INET6 3172 #define SYN_HASHALL(hash, src, dst) \ 3173 do { \ 3174 hash = SYN_HASH(&((const struct sockaddr_in *)(src))->sin_addr, \ 3175 ((const struct sockaddr_in *)(src))->sin_port, \ 3176 ((const struct sockaddr_in *)(dst))->sin_port); \ 3177 } while (/*CONSTCOND*/ 0) 3178 #else 3179 #define SYN_HASH6(sa, sp, dp) \ 3180 ((((sa)->s6_addr32[0] ^ (sa)->s6_addr32[3] ^ syn_hash1) * \ 3181 (((((u_int32_t)(dp))<<16) + ((u_int32_t)(sp)))^syn_hash2)) \ 3182 & 0x7fffffff) 3183 3184 #define SYN_HASHALL(hash, src, dst) \ 3185 do { \ 3186 switch ((src)->sa_family) { \ 3187 case AF_INET: \ 3188 hash = SYN_HASH(&((const struct sockaddr_in *)(src))->sin_addr, \ 3189 ((const struct sockaddr_in *)(src))->sin_port, \ 3190 ((const struct sockaddr_in *)(dst))->sin_port); \ 3191 break; \ 3192 case AF_INET6: \ 3193 hash = SYN_HASH6(&((const struct sockaddr_in6 *)(src))->sin6_addr, \ 3194 ((const struct sockaddr_in6 *)(src))->sin6_port, \ 3195 ((const struct sockaddr_in6 *)(dst))->sin6_port); \ 3196 break; \ 3197 default: \ 3198 hash = 0; \ 3199 } \ 3200 } while (/*CONSTCOND*/0) 3201 #endif /* INET6 */ 3202 3203 #define SYN_CACHE_RM(sc) \ 3204 do { \ 3205 TAILQ_REMOVE(&tcp_syn_cache[(sc)->sc_bucketidx].sch_bucket, \ 3206 (sc), sc_bucketq); \ 3207 (sc)->sc_tp = NULL; \ 3208 LIST_REMOVE((sc), sc_tpq); \ 3209 tcp_syn_cache[(sc)->sc_bucketidx].sch_length--; \ 3210 callout_stop(&(sc)->sc_timer); \ 3211 syn_cache_count--; \ 3212 } while (/*CONSTCOND*/0) 3213 3214 #define SYN_CACHE_PUT(sc) \ 3215 do { \ 3216 if ((sc)->sc_ipopts) \ 3217 (void) m_free((sc)->sc_ipopts); \ 3218 if ((sc)->sc_route4.ro_rt != NULL) \ 3219 RTFREE((sc)->sc_route4.ro_rt); \ 3220 if (callout_invoking(&(sc)->sc_timer)) \ 3221 (sc)->sc_flags |= SCF_DEAD; \ 3222 else \ 3223 pool_put(&syn_cache_pool, (sc)); \ 3224 } while (/*CONSTCOND*/0) 3225 3226 POOL_INIT(syn_cache_pool, sizeof(struct syn_cache), 0, 0, 0, "synpl", NULL); 3227 3228 /* 3229 * We don't estimate RTT with SYNs, so each packet starts with the default 3230 * RTT and each timer step has a fixed timeout value. 3231 */ 3232 #define SYN_CACHE_TIMER_ARM(sc) \ 3233 do { \ 3234 TCPT_RANGESET((sc)->sc_rxtcur, \ 3235 TCPTV_SRTTDFLT * tcp_backoff[(sc)->sc_rxtshift], TCPTV_MIN, \ 3236 TCPTV_REXMTMAX); \ 3237 callout_reset(&(sc)->sc_timer, \ 3238 (sc)->sc_rxtcur * (hz / PR_SLOWHZ), syn_cache_timer, (sc)); \ 3239 } while (/*CONSTCOND*/0) 3240 3241 #define SYN_CACHE_TIMESTAMP(sc) (tcp_now - (sc)->sc_timebase) 3242 3243 void 3244 syn_cache_init(void) 3245 { 3246 int i; 3247 3248 /* Initialize the hash buckets. */ 3249 for (i = 0; i < tcp_syn_cache_size; i++) 3250 TAILQ_INIT(&tcp_syn_cache[i].sch_bucket); 3251 } 3252 3253 void 3254 syn_cache_insert(struct syn_cache *sc, struct tcpcb *tp) 3255 { 3256 struct syn_cache_head *scp; 3257 struct syn_cache *sc2; 3258 int s; 3259 3260 /* 3261 * If there are no entries in the hash table, reinitialize 3262 * the hash secrets. 3263 */ 3264 if (syn_cache_count == 0) { 3265 syn_hash1 = arc4random(); 3266 syn_hash2 = arc4random(); 3267 } 3268 3269 SYN_HASHALL(sc->sc_hash, &sc->sc_src.sa, &sc->sc_dst.sa); 3270 sc->sc_bucketidx = sc->sc_hash % tcp_syn_cache_size; 3271 scp = &tcp_syn_cache[sc->sc_bucketidx]; 3272 3273 /* 3274 * Make sure that we don't overflow the per-bucket 3275 * limit or the total cache size limit. 3276 */ 3277 s = splsoftnet(); 3278 if (scp->sch_length >= tcp_syn_bucket_limit) { 3279 tcpstat.tcps_sc_bucketoverflow++; 3280 /* 3281 * The bucket is full. Toss the oldest element in the 3282 * bucket. This will be the first entry in the bucket. 3283 */ 3284 sc2 = TAILQ_FIRST(&scp->sch_bucket); 3285 #ifdef DIAGNOSTIC 3286 /* 3287 * This should never happen; we should always find an 3288 * entry in our bucket. 3289 */ 3290 if (sc2 == NULL) 3291 panic("syn_cache_insert: bucketoverflow: impossible"); 3292 #endif 3293 SYN_CACHE_RM(sc2); 3294 SYN_CACHE_PUT(sc2); /* calls pool_put but see spl above */ 3295 } else if (syn_cache_count >= tcp_syn_cache_limit) { 3296 struct syn_cache_head *scp2, *sce; 3297 3298 tcpstat.tcps_sc_overflowed++; 3299 /* 3300 * The cache is full. Toss the oldest entry in the 3301 * first non-empty bucket we can find. 3302 * 3303 * XXX We would really like to toss the oldest 3304 * entry in the cache, but we hope that this 3305 * condition doesn't happen very often. 3306 */ 3307 scp2 = scp; 3308 if (TAILQ_EMPTY(&scp2->sch_bucket)) { 3309 sce = &tcp_syn_cache[tcp_syn_cache_size]; 3310 for (++scp2; scp2 != scp; scp2++) { 3311 if (scp2 >= sce) 3312 scp2 = &tcp_syn_cache[0]; 3313 if (! TAILQ_EMPTY(&scp2->sch_bucket)) 3314 break; 3315 } 3316 #ifdef DIAGNOSTIC 3317 /* 3318 * This should never happen; we should always find a 3319 * non-empty bucket. 3320 */ 3321 if (scp2 == scp) 3322 panic("syn_cache_insert: cacheoverflow: " 3323 "impossible"); 3324 #endif 3325 } 3326 sc2 = TAILQ_FIRST(&scp2->sch_bucket); 3327 SYN_CACHE_RM(sc2); 3328 SYN_CACHE_PUT(sc2); /* calls pool_put but see spl above */ 3329 } 3330 3331 /* 3332 * Initialize the entry's timer. 3333 */ 3334 sc->sc_rxttot = 0; 3335 sc->sc_rxtshift = 0; 3336 SYN_CACHE_TIMER_ARM(sc); 3337 3338 /* Link it from tcpcb entry */ 3339 LIST_INSERT_HEAD(&tp->t_sc, sc, sc_tpq); 3340 3341 /* Put it into the bucket. */ 3342 TAILQ_INSERT_TAIL(&scp->sch_bucket, sc, sc_bucketq); 3343 scp->sch_length++; 3344 syn_cache_count++; 3345 3346 tcpstat.tcps_sc_added++; 3347 splx(s); 3348 } 3349 3350 /* 3351 * Walk the timer queues, looking for SYN,ACKs that need to be retransmitted. 3352 * If we have retransmitted an entry the maximum number of times, expire 3353 * that entry. 3354 */ 3355 void 3356 syn_cache_timer(void *arg) 3357 { 3358 struct syn_cache *sc = arg; 3359 int s; 3360 3361 s = splsoftnet(); 3362 callout_ack(&sc->sc_timer); 3363 3364 if (__predict_false(sc->sc_flags & SCF_DEAD)) { 3365 tcpstat.tcps_sc_delayed_free++; 3366 pool_put(&syn_cache_pool, sc); 3367 splx(s); 3368 return; 3369 } 3370 3371 if (__predict_false(sc->sc_rxtshift == TCP_MAXRXTSHIFT)) { 3372 /* Drop it -- too many retransmissions. */ 3373 goto dropit; 3374 } 3375 3376 /* 3377 * Compute the total amount of time this entry has 3378 * been on a queue. If this entry has been on longer 3379 * than the keep alive timer would allow, expire it. 3380 */ 3381 sc->sc_rxttot += sc->sc_rxtcur; 3382 if (sc->sc_rxttot >= TCPTV_KEEP_INIT) 3383 goto dropit; 3384 3385 tcpstat.tcps_sc_retransmitted++; 3386 (void) syn_cache_respond(sc, NULL); 3387 3388 /* Advance the timer back-off. */ 3389 sc->sc_rxtshift++; 3390 SYN_CACHE_TIMER_ARM(sc); 3391 3392 splx(s); 3393 return; 3394 3395 dropit: 3396 tcpstat.tcps_sc_timed_out++; 3397 SYN_CACHE_RM(sc); 3398 SYN_CACHE_PUT(sc); /* calls pool_put but see spl above */ 3399 splx(s); 3400 } 3401 3402 /* 3403 * Remove syn cache created by the specified tcb entry, 3404 * because this does not make sense to keep them 3405 * (if there's no tcb entry, syn cache entry will never be used) 3406 */ 3407 void 3408 syn_cache_cleanup(struct tcpcb *tp) 3409 { 3410 struct syn_cache *sc, *nsc; 3411 int s; 3412 3413 s = splsoftnet(); 3414 3415 for (sc = LIST_FIRST(&tp->t_sc); sc != NULL; sc = nsc) { 3416 nsc = LIST_NEXT(sc, sc_tpq); 3417 3418 #ifdef DIAGNOSTIC 3419 if (sc->sc_tp != tp) 3420 panic("invalid sc_tp in syn_cache_cleanup"); 3421 #endif 3422 SYN_CACHE_RM(sc); 3423 SYN_CACHE_PUT(sc); /* calls pool_put but see spl above */ 3424 } 3425 /* just for safety */ 3426 LIST_INIT(&tp->t_sc); 3427 3428 splx(s); 3429 } 3430 3431 /* 3432 * Find an entry in the syn cache. 3433 */ 3434 struct syn_cache * 3435 syn_cache_lookup(const struct sockaddr *src, const struct sockaddr *dst, 3436 struct syn_cache_head **headp) 3437 { 3438 struct syn_cache *sc; 3439 struct syn_cache_head *scp; 3440 u_int32_t hash; 3441 int s; 3442 3443 SYN_HASHALL(hash, src, dst); 3444 3445 scp = &tcp_syn_cache[hash % tcp_syn_cache_size]; 3446 *headp = scp; 3447 s = splsoftnet(); 3448 for (sc = TAILQ_FIRST(&scp->sch_bucket); sc != NULL; 3449 sc = TAILQ_NEXT(sc, sc_bucketq)) { 3450 if (sc->sc_hash != hash) 3451 continue; 3452 if (!bcmp(&sc->sc_src, src, src->sa_len) && 3453 !bcmp(&sc->sc_dst, dst, dst->sa_len)) { 3454 splx(s); 3455 return (sc); 3456 } 3457 } 3458 splx(s); 3459 return (NULL); 3460 } 3461 3462 /* 3463 * This function gets called when we receive an ACK for a 3464 * socket in the LISTEN state. We look up the connection 3465 * in the syn cache, and if its there, we pull it out of 3466 * the cache and turn it into a full-blown connection in 3467 * the SYN-RECEIVED state. 3468 * 3469 * The return values may not be immediately obvious, and their effects 3470 * can be subtle, so here they are: 3471 * 3472 * NULL SYN was not found in cache; caller should drop the 3473 * packet and send an RST. 3474 * 3475 * -1 We were unable to create the new connection, and are 3476 * aborting it. An ACK,RST is being sent to the peer 3477 * (unless we got screwey sequence numbners; see below), 3478 * because the 3-way handshake has been completed. Caller 3479 * should not free the mbuf, since we may be using it. If 3480 * we are not, we will free it. 3481 * 3482 * Otherwise, the return value is a pointer to the new socket 3483 * associated with the connection. 3484 */ 3485 struct socket * 3486 syn_cache_get(struct sockaddr *src, struct sockaddr *dst, 3487 struct tcphdr *th, unsigned int hlen __unused, unsigned int tlen __unused, 3488 struct socket *so, struct mbuf *m) 3489 { 3490 struct syn_cache *sc; 3491 struct syn_cache_head *scp; 3492 struct inpcb *inp = NULL; 3493 #ifdef INET6 3494 struct in6pcb *in6p = NULL; 3495 #endif 3496 struct tcpcb *tp = 0; 3497 struct mbuf *am; 3498 int s; 3499 struct socket *oso; 3500 3501 s = splsoftnet(); 3502 if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { 3503 splx(s); 3504 return (NULL); 3505 } 3506 3507 /* 3508 * Verify the sequence and ack numbers. Try getting the correct 3509 * response again. 3510 */ 3511 if ((th->th_ack != sc->sc_iss + 1) || 3512 SEQ_LEQ(th->th_seq, sc->sc_irs) || 3513 SEQ_GT(th->th_seq, sc->sc_irs + 1 + sc->sc_win)) { 3514 (void) syn_cache_respond(sc, m); 3515 splx(s); 3516 return ((struct socket *)(-1)); 3517 } 3518 3519 /* Remove this cache entry */ 3520 SYN_CACHE_RM(sc); 3521 splx(s); 3522 3523 /* 3524 * Ok, create the full blown connection, and set things up 3525 * as they would have been set up if we had created the 3526 * connection when the SYN arrived. If we can't create 3527 * the connection, abort it. 3528 */ 3529 /* 3530 * inp still has the OLD in_pcb stuff, set the 3531 * v6-related flags on the new guy, too. This is 3532 * done particularly for the case where an AF_INET6 3533 * socket is bound only to a port, and a v4 connection 3534 * comes in on that port. 3535 * we also copy the flowinfo from the original pcb 3536 * to the new one. 3537 */ 3538 oso = so; 3539 so = sonewconn(so, SS_ISCONNECTED); 3540 if (so == NULL) 3541 goto resetandabort; 3542 3543 switch (so->so_proto->pr_domain->dom_family) { 3544 #ifdef INET 3545 case AF_INET: 3546 inp = sotoinpcb(so); 3547 break; 3548 #endif 3549 #ifdef INET6 3550 case AF_INET6: 3551 in6p = sotoin6pcb(so); 3552 break; 3553 #endif 3554 } 3555 switch (src->sa_family) { 3556 #ifdef INET 3557 case AF_INET: 3558 if (inp) { 3559 inp->inp_laddr = ((struct sockaddr_in *)dst)->sin_addr; 3560 inp->inp_lport = ((struct sockaddr_in *)dst)->sin_port; 3561 inp->inp_options = ip_srcroute(); 3562 in_pcbstate(inp, INP_BOUND); 3563 if (inp->inp_options == NULL) { 3564 inp->inp_options = sc->sc_ipopts; 3565 sc->sc_ipopts = NULL; 3566 } 3567 } 3568 #ifdef INET6 3569 else if (in6p) { 3570 /* IPv4 packet to AF_INET6 socket */ 3571 bzero(&in6p->in6p_laddr, sizeof(in6p->in6p_laddr)); 3572 in6p->in6p_laddr.s6_addr16[5] = htons(0xffff); 3573 bcopy(&((struct sockaddr_in *)dst)->sin_addr, 3574 &in6p->in6p_laddr.s6_addr32[3], 3575 sizeof(((struct sockaddr_in *)dst)->sin_addr)); 3576 in6p->in6p_lport = ((struct sockaddr_in *)dst)->sin_port; 3577 in6totcpcb(in6p)->t_family = AF_INET; 3578 if (sotoin6pcb(oso)->in6p_flags & IN6P_IPV6_V6ONLY) 3579 in6p->in6p_flags |= IN6P_IPV6_V6ONLY; 3580 else 3581 in6p->in6p_flags &= ~IN6P_IPV6_V6ONLY; 3582 in6_pcbstate(in6p, IN6P_BOUND); 3583 } 3584 #endif 3585 break; 3586 #endif 3587 #ifdef INET6 3588 case AF_INET6: 3589 if (in6p) { 3590 in6p->in6p_laddr = ((struct sockaddr_in6 *)dst)->sin6_addr; 3591 in6p->in6p_lport = ((struct sockaddr_in6 *)dst)->sin6_port; 3592 in6_pcbstate(in6p, IN6P_BOUND); 3593 } 3594 break; 3595 #endif 3596 } 3597 #ifdef INET6 3598 if (in6p && in6totcpcb(in6p)->t_family == AF_INET6 && sotoinpcb(oso)) { 3599 struct in6pcb *oin6p = sotoin6pcb(oso); 3600 /* inherit socket options from the listening socket */ 3601 in6p->in6p_flags |= (oin6p->in6p_flags & IN6P_CONTROLOPTS); 3602 if (in6p->in6p_flags & IN6P_CONTROLOPTS) { 3603 m_freem(in6p->in6p_options); 3604 in6p->in6p_options = 0; 3605 } 3606 ip6_savecontrol(in6p, &in6p->in6p_options, 3607 mtod(m, struct ip6_hdr *), m); 3608 } 3609 #endif 3610 3611 #if defined(IPSEC) || defined(FAST_IPSEC) 3612 /* 3613 * we make a copy of policy, instead of sharing the policy, 3614 * for better behavior in terms of SA lookup and dead SA removal. 3615 */ 3616 if (inp) { 3617 /* copy old policy into new socket's */ 3618 if (ipsec_copy_pcbpolicy(sotoinpcb(oso)->inp_sp, inp->inp_sp)) 3619 printf("tcp_input: could not copy policy\n"); 3620 } 3621 #ifdef INET6 3622 else if (in6p) { 3623 /* copy old policy into new socket's */ 3624 if (ipsec_copy_pcbpolicy(sotoin6pcb(oso)->in6p_sp, 3625 in6p->in6p_sp)) 3626 printf("tcp_input: could not copy policy\n"); 3627 } 3628 #endif 3629 #endif 3630 3631 /* 3632 * Give the new socket our cached route reference. 3633 */ 3634 if (inp) 3635 inp->inp_route = sc->sc_route4; /* struct assignment */ 3636 #ifdef INET6 3637 else 3638 in6p->in6p_route = sc->sc_route6; 3639 #endif 3640 sc->sc_route4.ro_rt = NULL; 3641 3642 am = m_get(M_DONTWAIT, MT_SONAME); /* XXX */ 3643 if (am == NULL) 3644 goto resetandabort; 3645 MCLAIM(am, &tcp_mowner); 3646 am->m_len = src->sa_len; 3647 bcopy(src, mtod(am, caddr_t), src->sa_len); 3648 if (inp) { 3649 if (in_pcbconnect(inp, am, NULL)) { 3650 (void) m_free(am); 3651 goto resetandabort; 3652 } 3653 } 3654 #ifdef INET6 3655 else if (in6p) { 3656 if (src->sa_family == AF_INET) { 3657 /* IPv4 packet to AF_INET6 socket */ 3658 struct sockaddr_in6 *sin6; 3659 sin6 = mtod(am, struct sockaddr_in6 *); 3660 am->m_len = sizeof(*sin6); 3661 bzero(sin6, sizeof(*sin6)); 3662 sin6->sin6_family = AF_INET6; 3663 sin6->sin6_len = sizeof(*sin6); 3664 sin6->sin6_port = ((struct sockaddr_in *)src)->sin_port; 3665 sin6->sin6_addr.s6_addr16[5] = htons(0xffff); 3666 bcopy(&((struct sockaddr_in *)src)->sin_addr, 3667 &sin6->sin6_addr.s6_addr32[3], 3668 sizeof(sin6->sin6_addr.s6_addr32[3])); 3669 } 3670 if (in6_pcbconnect(in6p, am, NULL)) { 3671 (void) m_free(am); 3672 goto resetandabort; 3673 } 3674 } 3675 #endif 3676 else { 3677 (void) m_free(am); 3678 goto resetandabort; 3679 } 3680 (void) m_free(am); 3681 3682 if (inp) 3683 tp = intotcpcb(inp); 3684 #ifdef INET6 3685 else if (in6p) 3686 tp = in6totcpcb(in6p); 3687 #endif 3688 else 3689 tp = NULL; 3690 tp->t_flags = sototcpcb(oso)->t_flags & TF_NODELAY; 3691 if (sc->sc_request_r_scale != 15) { 3692 tp->requested_s_scale = sc->sc_requested_s_scale; 3693 tp->request_r_scale = sc->sc_request_r_scale; 3694 tp->snd_scale = sc->sc_requested_s_scale; 3695 tp->rcv_scale = sc->sc_request_r_scale; 3696 tp->t_flags |= TF_REQ_SCALE|TF_RCVD_SCALE; 3697 } 3698 if (sc->sc_flags & SCF_TIMESTAMP) 3699 tp->t_flags |= TF_REQ_TSTMP|TF_RCVD_TSTMP; 3700 tp->ts_timebase = sc->sc_timebase; 3701 3702 tp->t_template = tcp_template(tp); 3703 if (tp->t_template == 0) { 3704 tp = tcp_drop(tp, ENOBUFS); /* destroys socket */ 3705 so = NULL; 3706 m_freem(m); 3707 goto abort; 3708 } 3709 3710 tp->iss = sc->sc_iss; 3711 tp->irs = sc->sc_irs; 3712 tcp_sendseqinit(tp); 3713 tcp_rcvseqinit(tp); 3714 tp->t_state = TCPS_SYN_RECEIVED; 3715 TCP_TIMER_ARM(tp, TCPT_KEEP, TCPTV_KEEP_INIT); 3716 tcpstat.tcps_accepts++; 3717 3718 if ((sc->sc_flags & SCF_SACK_PERMIT) && tcp_do_sack) 3719 tp->t_flags |= TF_WILL_SACK; 3720 3721 if ((sc->sc_flags & SCF_ECN_PERMIT) && tcp_do_ecn) 3722 tp->t_flags |= TF_ECN_PERMIT; 3723 3724 #ifdef TCP_SIGNATURE 3725 if (sc->sc_flags & SCF_SIGNATURE) 3726 tp->t_flags |= TF_SIGNATURE; 3727 #endif 3728 3729 /* Initialize tp->t_ourmss before we deal with the peer's! */ 3730 tp->t_ourmss = sc->sc_ourmaxseg; 3731 tcp_mss_from_peer(tp, sc->sc_peermaxseg); 3732 3733 /* 3734 * Initialize the initial congestion window. If we 3735 * had to retransmit the SYN,ACK, we must initialize cwnd 3736 * to 1 segment (i.e. the Loss Window). 3737 */ 3738 if (sc->sc_rxtshift) 3739 tp->snd_cwnd = tp->t_peermss; 3740 else { 3741 int ss = tcp_init_win; 3742 #ifdef INET 3743 if (inp != NULL && in_localaddr(inp->inp_faddr)) 3744 ss = tcp_init_win_local; 3745 #endif 3746 #ifdef INET6 3747 if (in6p != NULL && in6_localaddr(&in6p->in6p_faddr)) 3748 ss = tcp_init_win_local; 3749 #endif 3750 tp->snd_cwnd = TCP_INITIAL_WINDOW(ss, tp->t_peermss); 3751 } 3752 3753 tcp_rmx_rtt(tp); 3754 tp->snd_wl1 = sc->sc_irs; 3755 tp->rcv_up = sc->sc_irs + 1; 3756 3757 /* 3758 * This is what whould have happened in tcp_output() when 3759 * the SYN,ACK was sent. 3760 */ 3761 tp->snd_up = tp->snd_una; 3762 tp->snd_max = tp->snd_nxt = tp->iss+1; 3763 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 3764 if (sc->sc_win > 0 && SEQ_GT(tp->rcv_nxt + sc->sc_win, tp->rcv_adv)) 3765 tp->rcv_adv = tp->rcv_nxt + sc->sc_win; 3766 tp->last_ack_sent = tp->rcv_nxt; 3767 tp->t_partialacks = -1; 3768 tp->t_dupacks = 0; 3769 3770 tcpstat.tcps_sc_completed++; 3771 s = splsoftnet(); 3772 SYN_CACHE_PUT(sc); 3773 splx(s); 3774 return (so); 3775 3776 resetandabort: 3777 (void)tcp_respond(NULL, m, m, th, (tcp_seq)0, th->th_ack, TH_RST); 3778 abort: 3779 if (so != NULL) 3780 (void) soabort(so); 3781 s = splsoftnet(); 3782 SYN_CACHE_PUT(sc); 3783 splx(s); 3784 tcpstat.tcps_sc_aborted++; 3785 return ((struct socket *)(-1)); 3786 } 3787 3788 /* 3789 * This function is called when we get a RST for a 3790 * non-existent connection, so that we can see if the 3791 * connection is in the syn cache. If it is, zap it. 3792 */ 3793 3794 void 3795 syn_cache_reset(struct sockaddr *src, struct sockaddr *dst, struct tcphdr *th) 3796 { 3797 struct syn_cache *sc; 3798 struct syn_cache_head *scp; 3799 int s = splsoftnet(); 3800 3801 if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { 3802 splx(s); 3803 return; 3804 } 3805 if (SEQ_LT(th->th_seq, sc->sc_irs) || 3806 SEQ_GT(th->th_seq, sc->sc_irs+1)) { 3807 splx(s); 3808 return; 3809 } 3810 SYN_CACHE_RM(sc); 3811 tcpstat.tcps_sc_reset++; 3812 SYN_CACHE_PUT(sc); /* calls pool_put but see spl above */ 3813 splx(s); 3814 } 3815 3816 void 3817 syn_cache_unreach(const struct sockaddr *src, const struct sockaddr *dst, 3818 struct tcphdr *th) 3819 { 3820 struct syn_cache *sc; 3821 struct syn_cache_head *scp; 3822 int s; 3823 3824 s = splsoftnet(); 3825 if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { 3826 splx(s); 3827 return; 3828 } 3829 /* If the sequence number != sc_iss, then it's a bogus ICMP msg */ 3830 if (ntohl (th->th_seq) != sc->sc_iss) { 3831 splx(s); 3832 return; 3833 } 3834 3835 /* 3836 * If we've retransmitted 3 times and this is our second error, 3837 * we remove the entry. Otherwise, we allow it to continue on. 3838 * This prevents us from incorrectly nuking an entry during a 3839 * spurious network outage. 3840 * 3841 * See tcp_notify(). 3842 */ 3843 if ((sc->sc_flags & SCF_UNREACH) == 0 || sc->sc_rxtshift < 3) { 3844 sc->sc_flags |= SCF_UNREACH; 3845 splx(s); 3846 return; 3847 } 3848 3849 SYN_CACHE_RM(sc); 3850 tcpstat.tcps_sc_unreach++; 3851 SYN_CACHE_PUT(sc); /* calls pool_put but see spl above */ 3852 splx(s); 3853 } 3854 3855 /* 3856 * Given a LISTEN socket and an inbound SYN request, add 3857 * this to the syn cache, and send back a segment: 3858 * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK> 3859 * to the source. 3860 * 3861 * IMPORTANT NOTE: We do _NOT_ ACK data that might accompany the SYN. 3862 * Doing so would require that we hold onto the data and deliver it 3863 * to the application. However, if we are the target of a SYN-flood 3864 * DoS attack, an attacker could send data which would eventually 3865 * consume all available buffer space if it were ACKed. By not ACKing 3866 * the data, we avoid this DoS scenario. 3867 */ 3868 3869 int 3870 syn_cache_add(struct sockaddr *src, struct sockaddr *dst, struct tcphdr *th, 3871 unsigned int hlen, struct socket *so, struct mbuf *m, u_char *optp, 3872 int optlen, struct tcp_opt_info *oi) 3873 { 3874 struct tcpcb tb, *tp; 3875 long win; 3876 struct syn_cache *sc; 3877 struct syn_cache_head *scp; 3878 struct mbuf *ipopts; 3879 struct tcp_opt_info opti; 3880 int s; 3881 3882 tp = sototcpcb(so); 3883 3884 bzero(&opti, sizeof(opti)); 3885 3886 /* 3887 * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN 3888 * 3889 * Note this check is performed in tcp_input() very early on. 3890 */ 3891 3892 /* 3893 * Initialize some local state. 3894 */ 3895 win = sbspace(&so->so_rcv); 3896 if (win > TCP_MAXWIN) 3897 win = TCP_MAXWIN; 3898 3899 switch (src->sa_family) { 3900 #ifdef INET 3901 case AF_INET: 3902 /* 3903 * Remember the IP options, if any. 3904 */ 3905 ipopts = ip_srcroute(); 3906 break; 3907 #endif 3908 default: 3909 ipopts = NULL; 3910 } 3911 3912 #ifdef TCP_SIGNATURE 3913 if (optp || (tp->t_flags & TF_SIGNATURE)) 3914 #else 3915 if (optp) 3916 #endif 3917 { 3918 tb.t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; 3919 #ifdef TCP_SIGNATURE 3920 tb.t_flags |= (tp->t_flags & TF_SIGNATURE); 3921 #endif 3922 tb.t_state = TCPS_LISTEN; 3923 if (tcp_dooptions(&tb, optp, optlen, th, m, m->m_pkthdr.len - 3924 sizeof(struct tcphdr) - optlen - hlen, oi) < 0) 3925 return (0); 3926 } else 3927 tb.t_flags = 0; 3928 3929 /* 3930 * See if we already have an entry for this connection. 3931 * If we do, resend the SYN,ACK. We do not count this 3932 * as a retransmission (XXX though maybe we should). 3933 */ 3934 if ((sc = syn_cache_lookup(src, dst, &scp)) != NULL) { 3935 tcpstat.tcps_sc_dupesyn++; 3936 if (ipopts) { 3937 /* 3938 * If we were remembering a previous source route, 3939 * forget it and use the new one we've been given. 3940 */ 3941 if (sc->sc_ipopts) 3942 (void) m_free(sc->sc_ipopts); 3943 sc->sc_ipopts = ipopts; 3944 } 3945 sc->sc_timestamp = tb.ts_recent; 3946 if (syn_cache_respond(sc, m) == 0) { 3947 tcpstat.tcps_sndacks++; 3948 tcpstat.tcps_sndtotal++; 3949 } 3950 return (1); 3951 } 3952 3953 s = splsoftnet(); 3954 sc = pool_get(&syn_cache_pool, PR_NOWAIT); 3955 splx(s); 3956 if (sc == NULL) { 3957 if (ipopts) 3958 (void) m_free(ipopts); 3959 return (0); 3960 } 3961 3962 /* 3963 * Fill in the cache, and put the necessary IP and TCP 3964 * options into the reply. 3965 */ 3966 bzero(sc, sizeof(struct syn_cache)); 3967 callout_init(&sc->sc_timer); 3968 bcopy(src, &sc->sc_src, src->sa_len); 3969 bcopy(dst, &sc->sc_dst, dst->sa_len); 3970 sc->sc_flags = 0; 3971 sc->sc_ipopts = ipopts; 3972 sc->sc_irs = th->th_seq; 3973 switch (src->sa_family) { 3974 #ifdef INET 3975 case AF_INET: 3976 { 3977 struct sockaddr_in *srcin = (void *) src; 3978 struct sockaddr_in *dstin = (void *) dst; 3979 3980 sc->sc_iss = tcp_new_iss1(&dstin->sin_addr, 3981 &srcin->sin_addr, dstin->sin_port, 3982 srcin->sin_port, sizeof(dstin->sin_addr), 0); 3983 break; 3984 } 3985 #endif /* INET */ 3986 #ifdef INET6 3987 case AF_INET6: 3988 { 3989 struct sockaddr_in6 *srcin6 = (void *) src; 3990 struct sockaddr_in6 *dstin6 = (void *) dst; 3991 3992 sc->sc_iss = tcp_new_iss1(&dstin6->sin6_addr, 3993 &srcin6->sin6_addr, dstin6->sin6_port, 3994 srcin6->sin6_port, sizeof(dstin6->sin6_addr), 0); 3995 break; 3996 } 3997 #endif /* INET6 */ 3998 } 3999 sc->sc_peermaxseg = oi->maxseg; 4000 sc->sc_ourmaxseg = tcp_mss_to_advertise(m->m_flags & M_PKTHDR ? 4001 m->m_pkthdr.rcvif : NULL, 4002 sc->sc_src.sa.sa_family); 4003 sc->sc_win = win; 4004 sc->sc_timebase = tcp_now; /* see tcp_newtcpcb() */ 4005 sc->sc_timestamp = tb.ts_recent; 4006 if ((tb.t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP)) == 4007 (TF_REQ_TSTMP|TF_RCVD_TSTMP)) 4008 sc->sc_flags |= SCF_TIMESTAMP; 4009 if ((tb.t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == 4010 (TF_RCVD_SCALE|TF_REQ_SCALE)) { 4011 sc->sc_requested_s_scale = tb.requested_s_scale; 4012 sc->sc_request_r_scale = 0; 4013 while (sc->sc_request_r_scale < TCP_MAX_WINSHIFT && 4014 TCP_MAXWIN << sc->sc_request_r_scale < 4015 so->so_rcv.sb_hiwat) 4016 sc->sc_request_r_scale++; 4017 } else { 4018 sc->sc_requested_s_scale = 15; 4019 sc->sc_request_r_scale = 15; 4020 } 4021 if ((tb.t_flags & TF_SACK_PERMIT) && tcp_do_sack) 4022 sc->sc_flags |= SCF_SACK_PERMIT; 4023 4024 /* 4025 * ECN setup packet recieved. 4026 */ 4027 if ((th->th_flags & (TH_ECE|TH_CWR)) && tcp_do_ecn) 4028 sc->sc_flags |= SCF_ECN_PERMIT; 4029 4030 #ifdef TCP_SIGNATURE 4031 if (tb.t_flags & TF_SIGNATURE) 4032 sc->sc_flags |= SCF_SIGNATURE; 4033 #endif 4034 sc->sc_tp = tp; 4035 if (syn_cache_respond(sc, m) == 0) { 4036 syn_cache_insert(sc, tp); 4037 tcpstat.tcps_sndacks++; 4038 tcpstat.tcps_sndtotal++; 4039 } else { 4040 s = splsoftnet(); 4041 SYN_CACHE_PUT(sc); 4042 splx(s); 4043 tcpstat.tcps_sc_dropped++; 4044 } 4045 return (1); 4046 } 4047 4048 int 4049 syn_cache_respond(struct syn_cache *sc, struct mbuf *m) 4050 { 4051 struct route *ro; 4052 u_int8_t *optp; 4053 int optlen, error; 4054 u_int16_t tlen; 4055 struct ip *ip = NULL; 4056 #ifdef INET6 4057 struct ip6_hdr *ip6 = NULL; 4058 #endif 4059 struct tcpcb *tp = NULL; 4060 struct tcphdr *th; 4061 u_int hlen; 4062 struct socket *so; 4063 4064 switch (sc->sc_src.sa.sa_family) { 4065 case AF_INET: 4066 hlen = sizeof(struct ip); 4067 ro = &sc->sc_route4; 4068 break; 4069 #ifdef INET6 4070 case AF_INET6: 4071 hlen = sizeof(struct ip6_hdr); 4072 ro = (struct route *)&sc->sc_route6; 4073 break; 4074 #endif 4075 default: 4076 if (m) 4077 m_freem(m); 4078 return (EAFNOSUPPORT); 4079 } 4080 4081 /* Compute the size of the TCP options. */ 4082 optlen = 4 + (sc->sc_request_r_scale != 15 ? 4 : 0) + 4083 ((sc->sc_flags & SCF_SACK_PERMIT) ? (TCPOLEN_SACK_PERMITTED + 2) : 0) + 4084 #ifdef TCP_SIGNATURE 4085 ((sc->sc_flags & SCF_SIGNATURE) ? (TCPOLEN_SIGNATURE + 2) : 0) + 4086 #endif 4087 ((sc->sc_flags & SCF_TIMESTAMP) ? TCPOLEN_TSTAMP_APPA : 0); 4088 4089 tlen = hlen + sizeof(struct tcphdr) + optlen; 4090 4091 /* 4092 * Create the IP+TCP header from scratch. 4093 */ 4094 if (m) 4095 m_freem(m); 4096 #ifdef DIAGNOSTIC 4097 if (max_linkhdr + tlen > MCLBYTES) 4098 return (ENOBUFS); 4099 #endif 4100 MGETHDR(m, M_DONTWAIT, MT_DATA); 4101 if (m && tlen > MHLEN) { 4102 MCLGET(m, M_DONTWAIT); 4103 if ((m->m_flags & M_EXT) == 0) { 4104 m_freem(m); 4105 m = NULL; 4106 } 4107 } 4108 if (m == NULL) 4109 return (ENOBUFS); 4110 MCLAIM(m, &tcp_tx_mowner); 4111 4112 /* Fixup the mbuf. */ 4113 m->m_data += max_linkhdr; 4114 m->m_len = m->m_pkthdr.len = tlen; 4115 if (sc->sc_tp) { 4116 tp = sc->sc_tp; 4117 if (tp->t_inpcb) 4118 so = tp->t_inpcb->inp_socket; 4119 #ifdef INET6 4120 else if (tp->t_in6pcb) 4121 so = tp->t_in6pcb->in6p_socket; 4122 #endif 4123 else 4124 so = NULL; 4125 } else 4126 so = NULL; 4127 m->m_pkthdr.rcvif = NULL; 4128 memset(mtod(m, u_char *), 0, tlen); 4129 4130 switch (sc->sc_src.sa.sa_family) { 4131 case AF_INET: 4132 ip = mtod(m, struct ip *); 4133 ip->ip_v = 4; 4134 ip->ip_dst = sc->sc_src.sin.sin_addr; 4135 ip->ip_src = sc->sc_dst.sin.sin_addr; 4136 ip->ip_p = IPPROTO_TCP; 4137 th = (struct tcphdr *)(ip + 1); 4138 th->th_dport = sc->sc_src.sin.sin_port; 4139 th->th_sport = sc->sc_dst.sin.sin_port; 4140 break; 4141 #ifdef INET6 4142 case AF_INET6: 4143 ip6 = mtod(m, struct ip6_hdr *); 4144 ip6->ip6_vfc = IPV6_VERSION; 4145 ip6->ip6_dst = sc->sc_src.sin6.sin6_addr; 4146 ip6->ip6_src = sc->sc_dst.sin6.sin6_addr; 4147 ip6->ip6_nxt = IPPROTO_TCP; 4148 /* ip6_plen will be updated in ip6_output() */ 4149 th = (struct tcphdr *)(ip6 + 1); 4150 th->th_dport = sc->sc_src.sin6.sin6_port; 4151 th->th_sport = sc->sc_dst.sin6.sin6_port; 4152 break; 4153 #endif 4154 default: 4155 th = NULL; 4156 } 4157 4158 th->th_seq = htonl(sc->sc_iss); 4159 th->th_ack = htonl(sc->sc_irs + 1); 4160 th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; 4161 th->th_flags = TH_SYN|TH_ACK; 4162 th->th_win = htons(sc->sc_win); 4163 /* th_sum already 0 */ 4164 /* th_urp already 0 */ 4165 4166 /* Tack on the TCP options. */ 4167 optp = (u_int8_t *)(th + 1); 4168 *optp++ = TCPOPT_MAXSEG; 4169 *optp++ = 4; 4170 *optp++ = (sc->sc_ourmaxseg >> 8) & 0xff; 4171 *optp++ = sc->sc_ourmaxseg & 0xff; 4172 4173 if (sc->sc_request_r_scale != 15) { 4174 *((u_int32_t *)optp) = htonl(TCPOPT_NOP << 24 | 4175 TCPOPT_WINDOW << 16 | TCPOLEN_WINDOW << 8 | 4176 sc->sc_request_r_scale); 4177 optp += 4; 4178 } 4179 4180 if (sc->sc_flags & SCF_TIMESTAMP) { 4181 u_int32_t *lp = (u_int32_t *)(optp); 4182 /* Form timestamp option as shown in appendix A of RFC 1323. */ 4183 *lp++ = htonl(TCPOPT_TSTAMP_HDR); 4184 *lp++ = htonl(SYN_CACHE_TIMESTAMP(sc)); 4185 *lp = htonl(sc->sc_timestamp); 4186 optp += TCPOLEN_TSTAMP_APPA; 4187 } 4188 4189 if (sc->sc_flags & SCF_SACK_PERMIT) { 4190 u_int8_t *p = optp; 4191 4192 /* Let the peer know that we will SACK. */ 4193 p[0] = TCPOPT_SACK_PERMITTED; 4194 p[1] = 2; 4195 p[2] = TCPOPT_NOP; 4196 p[3] = TCPOPT_NOP; 4197 optp += 4; 4198 } 4199 4200 /* 4201 * Send ECN SYN-ACK setup packet. 4202 * Routes can be asymetric, so, even if we receive a packet 4203 * with ECE and CWR set, we must not assume no one will block 4204 * the ECE packet we are about to send. 4205 */ 4206 if ((sc->sc_flags & SCF_ECN_PERMIT) && tp && 4207 SEQ_GEQ(tp->snd_nxt, tp->snd_max)) { 4208 th->th_flags |= TH_ECE; 4209 tcpstat.tcps_ecn_shs++; 4210 4211 /* 4212 * draft-ietf-tcpm-ecnsyn-00.txt 4213 * 4214 * "[...] a TCP node MAY respond to an ECN-setup 4215 * SYN packet by setting ECT in the responding 4216 * ECN-setup SYN/ACK packet, indicating to routers 4217 * that the SYN/ACK packet is ECN-Capable. 4218 * This allows a congested router along the path 4219 * to mark the packet instead of dropping the 4220 * packet as an indication of congestion." 4221 * 4222 * "[...] There can be a great benefit in setting 4223 * an ECN-capable codepoint in SYN/ACK packets [...] 4224 * Congestion is most likely to occur in 4225 * the server-to-client direction. As a result, 4226 * setting an ECN-capable codepoint in SYN/ACK 4227 * packets can reduce the occurence of three-second 4228 * retransmit timeouts resulting from the drop 4229 * of SYN/ACK packets." 4230 * 4231 * Page 4 and 6, January 2006. 4232 */ 4233 4234 switch (sc->sc_src.sa.sa_family) { 4235 #ifdef INET 4236 case AF_INET: 4237 ip->ip_tos |= IPTOS_ECN_ECT0; 4238 break; 4239 #endif 4240 #ifdef INET6 4241 case AF_INET6: 4242 ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20); 4243 break; 4244 #endif 4245 } 4246 tcpstat.tcps_ecn_ect++; 4247 } 4248 4249 #ifdef TCP_SIGNATURE 4250 if (sc->sc_flags & SCF_SIGNATURE) { 4251 struct secasvar *sav; 4252 u_int8_t *sigp; 4253 4254 sav = tcp_signature_getsav(m, th); 4255 4256 if (sav == NULL) { 4257 if (m) 4258 m_freem(m); 4259 return (EPERM); 4260 } 4261 4262 *optp++ = TCPOPT_SIGNATURE; 4263 *optp++ = TCPOLEN_SIGNATURE; 4264 sigp = optp; 4265 bzero(optp, TCP_SIGLEN); 4266 optp += TCP_SIGLEN; 4267 *optp++ = TCPOPT_NOP; 4268 *optp++ = TCPOPT_EOL; 4269 4270 (void)tcp_signature(m, th, hlen, sav, sigp); 4271 4272 key_sa_recordxfer(sav, m); 4273 #ifdef FAST_IPSEC 4274 KEY_FREESAV(&sav); 4275 #else 4276 key_freesav(sav); 4277 #endif 4278 } 4279 #endif 4280 4281 /* Compute the packet's checksum. */ 4282 switch (sc->sc_src.sa.sa_family) { 4283 case AF_INET: 4284 ip->ip_len = htons(tlen - hlen); 4285 th->th_sum = 0; 4286 th->th_sum = in4_cksum(m, IPPROTO_TCP, hlen, tlen - hlen); 4287 break; 4288 #ifdef INET6 4289 case AF_INET6: 4290 ip6->ip6_plen = htons(tlen - hlen); 4291 th->th_sum = 0; 4292 th->th_sum = in6_cksum(m, IPPROTO_TCP, hlen, tlen - hlen); 4293 break; 4294 #endif 4295 } 4296 4297 /* 4298 * Fill in some straggling IP bits. Note the stack expects 4299 * ip_len to be in host order, for convenience. 4300 */ 4301 switch (sc->sc_src.sa.sa_family) { 4302 #ifdef INET 4303 case AF_INET: 4304 ip->ip_len = htons(tlen); 4305 ip->ip_ttl = ip_defttl; 4306 /* XXX tos? */ 4307 break; 4308 #endif 4309 #ifdef INET6 4310 case AF_INET6: 4311 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 4312 ip6->ip6_vfc |= IPV6_VERSION; 4313 ip6->ip6_plen = htons(tlen - hlen); 4314 /* ip6_hlim will be initialized afterwards */ 4315 /* XXX flowlabel? */ 4316 break; 4317 #endif 4318 } 4319 4320 /* XXX use IPsec policy on listening socket, on SYN ACK */ 4321 tp = sc->sc_tp; 4322 4323 switch (sc->sc_src.sa.sa_family) { 4324 #ifdef INET 4325 case AF_INET: 4326 error = ip_output(m, sc->sc_ipopts, ro, 4327 (ip_mtudisc ? IP_MTUDISC : 0), 4328 (struct ip_moptions *)NULL, so); 4329 break; 4330 #endif 4331 #ifdef INET6 4332 case AF_INET6: 4333 ip6->ip6_hlim = in6_selecthlim(NULL, 4334 ro->ro_rt ? ro->ro_rt->rt_ifp : NULL); 4335 4336 error = ip6_output(m, NULL /*XXX*/, (struct route_in6 *)ro, 0, 4337 (struct ip6_moptions *)0, so, NULL); 4338 break; 4339 #endif 4340 default: 4341 error = EAFNOSUPPORT; 4342 break; 4343 } 4344 return (error); 4345 } 4346
Indexes created Mon Sep 22 10:09:38 GMT 2025