1 /* 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 34 * $FreeBSD$ 35 */ 36 37 #include "opt_compat.h" 38 #include "opt_inet6.h" 39 #include "opt_ipsec.h" 40 #include "opt_tcpdebug.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/callout.h> 45 #include <sys/kernel.h> 46 #include <sys/sysctl.h> 47 #include <sys/malloc.h> 48 #include <sys/mbuf.h> 49 #ifdef INET6 50 #include <sys/domain.h> 51 #endif 52 #include <sys/proc.h> 53 #include <sys/socket.h> 54 #include <sys/socketvar.h> 55 #include <sys/protosw.h> 56 #include <sys/random.h> 57 58 #include <vm/uma.h> 59 60 #include <net/route.h> 61 #include <net/if.h> 62 63 #define _IP_VHL 64 #include <netinet/in.h> 65 #include <netinet/in_systm.h> 66 #include <netinet/ip.h> 67 #ifdef INET6 68 #include <netinet/ip6.h> 69 #endif 70 #include <netinet/in_pcb.h> 71 #ifdef INET6 72 #include <netinet6/in6_pcb.h> 73 #endif 74 #include <netinet/in_var.h> 75 #include <netinet/ip_var.h> 76 #ifdef INET6 77 #include <netinet6/ip6_var.h> 78 #endif 79 #include <netinet/tcp.h> 80 #include <netinet/tcp_fsm.h> 81 #include <netinet/tcp_seq.h> 82 #include <netinet/tcp_timer.h> 83 #include <netinet/tcp_var.h> 84 #ifdef INET6 85 #include <netinet6/tcp6_var.h> 86 #endif 87 #include <netinet/tcpip.h> 88 #ifdef TCPDEBUG 89 #include <netinet/tcp_debug.h> 90 #endif 91 #include <netinet6/ip6protosw.h> 92 93 #ifdef IPSEC 94 #include <netinet6/ipsec.h> 95 #ifdef INET6 96 #include <netinet6/ipsec6.h> 97 #endif 98 #endif /*IPSEC*/ 99 100 #include <machine/in_cksum.h> 101 #include <sys/md5.h> 102 103 int tcp_mssdflt = TCP_MSS; 104 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 105 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size"); 106 107 #ifdef INET6 108 int tcp_v6mssdflt = TCP6_MSS; 109 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 110 CTLFLAG_RW, &tcp_v6mssdflt , 0, 111 "Default TCP Maximum Segment Size for IPv6"); 112 #endif 113 114 #if 0 115 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 116 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 117 &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time"); 118 #endif 119 120 int tcp_do_rfc1323 = 1; 121 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 122 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions"); 123 124 int tcp_do_rfc1644 = 0; 125 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 126 &tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions"); 127 128 static int tcp_tcbhashsize = 0; 129 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 130 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 131 132 static int do_tcpdrain = 1; 133 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 134 "Enable tcp_drain routine for extra help when low on mbufs"); 135 136 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 137 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 138 139 static int icmp_may_rst = 1; 140 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 141 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 142 143 static int tcp_strict_rfc1948 = 0; 144 SYSCTL_INT(_net_inet_tcp, OID_AUTO, strict_rfc1948, CTLFLAG_RW, 145 &tcp_strict_rfc1948, 0, "Determines if RFC1948 is followed exactly"); 146 147 static int tcp_isn_reseed_interval = 0; 148 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 149 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 150 151 static void tcp_cleartaocache(void); 152 static void tcp_notify(struct inpcb *, int); 153 154 /* 155 * Target size of TCP PCB hash tables. Must be a power of two. 156 * 157 * Note that this can be overridden by the kernel environment 158 * variable net.inet.tcp.tcbhashsize 159 */ 160 #ifndef TCBHASHSIZE 161 #define TCBHASHSIZE 512 162 #endif 163 164 /* 165 * This is the actual shape of what we allocate using the zone 166 * allocator. Doing it this way allows us to protect both structures 167 * using the same generation count, and also eliminates the overhead 168 * of allocating tcpcbs separately. By hiding the structure here, 169 * we avoid changing most of the rest of the code (although it needs 170 * to be changed, eventually, for greater efficiency). 171 */ 172 #define ALIGNMENT 32 173 #define ALIGNM1 (ALIGNMENT - 1) 174 struct inp_tp { 175 union { 176 struct inpcb inp; 177 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 178 } inp_tp_u; 179 struct tcpcb tcb; 180 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl; 181 struct callout inp_tp_delack; 182 }; 183 #undef ALIGNMENT 184 #undef ALIGNM1 185 186 /* 187 * Tcp initialization 188 */ 189 void 190 tcp_init() 191 { 192 int hashsize = TCBHASHSIZE; 193 194 tcp_ccgen = 1; 195 tcp_cleartaocache(); 196 197 tcp_delacktime = TCPTV_DELACK; 198 tcp_keepinit = TCPTV_KEEP_INIT; 199 tcp_keepidle = TCPTV_KEEP_IDLE; 200 tcp_keepintvl = TCPTV_KEEPINTVL; 201 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 202 tcp_msl = TCPTV_MSL; 203 204 LIST_INIT(&tcb); 205 tcbinfo.listhead = &tcb; 206 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 207 if (!powerof2(hashsize)) { 208 printf("WARNING: TCB hash size not a power of 2\n"); 209 hashsize = 512; /* safe default */ 210 } 211 tcp_tcbhashsize = hashsize; 212 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask); 213 tcbinfo.porthashbase = hashinit(hashsize, M_PCB, 214 &tcbinfo.porthashmask); 215 tcbinfo.ipi_zone = uma_zcreate("tcpcb", sizeof(struct inp_tp), 216 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 217 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 218 #ifdef INET6 219 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 220 #else /* INET6 */ 221 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 222 #endif /* INET6 */ 223 if (max_protohdr < TCP_MINPROTOHDR) 224 max_protohdr = TCP_MINPROTOHDR; 225 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 226 panic("tcp_init"); 227 #undef TCP_MINPROTOHDR 228 229 syncache_init(); 230 } 231 232 /* 233 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 234 * tcp_template used to store this data in mbufs, but we now recopy it out 235 * of the tcpcb each time to conserve mbufs. 236 */ 237 void 238 tcp_fillheaders(tp, ip_ptr, tcp_ptr) 239 struct tcpcb *tp; 240 void *ip_ptr; 241 void *tcp_ptr; 242 { 243 struct inpcb *inp = tp->t_inpcb; 244 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 245 246 #ifdef INET6 247 if ((inp->inp_vflag & INP_IPV6) != 0) { 248 struct ip6_hdr *ip6; 249 250 ip6 = (struct ip6_hdr *)ip_ptr; 251 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 252 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 253 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 254 (IPV6_VERSION & IPV6_VERSION_MASK); 255 ip6->ip6_nxt = IPPROTO_TCP; 256 ip6->ip6_plen = sizeof(struct tcphdr); 257 ip6->ip6_src = inp->in6p_laddr; 258 ip6->ip6_dst = inp->in6p_faddr; 259 tcp_hdr->th_sum = 0; 260 } else 261 #endif 262 { 263 struct ip *ip = (struct ip *) ip_ptr; 264 265 ip->ip_vhl = IP_VHL_BORING; 266 ip->ip_tos = 0; 267 ip->ip_len = 0; 268 ip->ip_id = 0; 269 ip->ip_off = 0; 270 ip->ip_ttl = 0; 271 ip->ip_sum = 0; 272 ip->ip_p = IPPROTO_TCP; 273 ip->ip_src = inp->inp_laddr; 274 ip->ip_dst = inp->inp_faddr; 275 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 276 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 277 } 278 279 tcp_hdr->th_sport = inp->inp_lport; 280 tcp_hdr->th_dport = inp->inp_fport; 281 tcp_hdr->th_seq = 0; 282 tcp_hdr->th_ack = 0; 283 tcp_hdr->th_x2 = 0; 284 tcp_hdr->th_off = 5; 285 tcp_hdr->th_flags = 0; 286 tcp_hdr->th_win = 0; 287 tcp_hdr->th_urp = 0; 288 } 289 290 /* 291 * Create template to be used to send tcp packets on a connection. 292 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 293 * use for this function is in keepalives, which use tcp_respond. 294 */ 295 struct tcptemp * 296 tcp_maketemplate(tp) 297 struct tcpcb *tp; 298 { 299 struct mbuf *m; 300 struct tcptemp *n; 301 302 m = m_get(M_DONTWAIT, MT_HEADER); 303 if (m == NULL) 304 return (0); 305 m->m_len = sizeof(struct tcptemp); 306 n = mtod(m, struct tcptemp *); 307 308 tcp_fillheaders(tp, (void *)&n->tt_ipgen, (void *)&n->tt_t); 309 return (n); 310 } 311 312 /* 313 * Send a single message to the TCP at address specified by 314 * the given TCP/IP header. If m == 0, then we make a copy 315 * of the tcpiphdr at ti and send directly to the addressed host. 316 * This is used to force keep alive messages out using the TCP 317 * template for a connection. If flags are given then we send 318 * a message back to the TCP which originated the * segment ti, 319 * and discard the mbuf containing it and any other attached mbufs. 320 * 321 * In any case the ack and sequence number of the transmitted 322 * segment are as specified by the parameters. 323 * 324 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 325 */ 326 void 327 tcp_respond(tp, ipgen, th, m, ack, seq, flags) 328 struct tcpcb *tp; 329 void *ipgen; 330 register struct tcphdr *th; 331 register struct mbuf *m; 332 tcp_seq ack, seq; 333 int flags; 334 { 335 register int tlen; 336 int win = 0; 337 struct route *ro = 0; 338 struct route sro; 339 struct ip *ip; 340 struct tcphdr *nth; 341 #ifdef INET6 342 struct route_in6 *ro6 = 0; 343 struct route_in6 sro6; 344 struct ip6_hdr *ip6; 345 int isipv6; 346 #endif /* INET6 */ 347 int ipflags = 0; 348 349 #ifdef INET6 350 isipv6 = IP_VHL_V(((struct ip *)ipgen)->ip_vhl) == 6; 351 ip6 = ipgen; 352 #endif /* INET6 */ 353 ip = ipgen; 354 355 if (tp) { 356 if (!(flags & TH_RST)) { 357 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 358 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 359 win = (long)TCP_MAXWIN << tp->rcv_scale; 360 } 361 #ifdef INET6 362 if (isipv6) 363 ro6 = &tp->t_inpcb->in6p_route; 364 else 365 #endif /* INET6 */ 366 ro = &tp->t_inpcb->inp_route; 367 } else { 368 #ifdef INET6 369 if (isipv6) { 370 ro6 = &sro6; 371 bzero(ro6, sizeof *ro6); 372 } else 373 #endif /* INET6 */ 374 { 375 ro = &sro; 376 bzero(ro, sizeof *ro); 377 } 378 } 379 if (m == 0) { 380 m = m_gethdr(M_DONTWAIT, MT_HEADER); 381 if (m == NULL) 382 return; 383 tlen = 0; 384 m->m_data += max_linkhdr; 385 #ifdef INET6 386 if (isipv6) { 387 bcopy((caddr_t)ip6, mtod(m, caddr_t), 388 sizeof(struct ip6_hdr)); 389 ip6 = mtod(m, struct ip6_hdr *); 390 nth = (struct tcphdr *)(ip6 + 1); 391 } else 392 #endif /* INET6 */ 393 { 394 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 395 ip = mtod(m, struct ip *); 396 nth = (struct tcphdr *)(ip + 1); 397 } 398 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 399 flags = TH_ACK; 400 } else { 401 m_freem(m->m_next); 402 m->m_next = 0; 403 m->m_data = (caddr_t)ipgen; 404 /* m_len is set later */ 405 tlen = 0; 406 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 407 #ifdef INET6 408 if (isipv6) { 409 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 410 nth = (struct tcphdr *)(ip6 + 1); 411 } else 412 #endif /* INET6 */ 413 { 414 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 415 nth = (struct tcphdr *)(ip + 1); 416 } 417 if (th != nth) { 418 /* 419 * this is usually a case when an extension header 420 * exists between the IPv6 header and the 421 * TCP header. 422 */ 423 nth->th_sport = th->th_sport; 424 nth->th_dport = th->th_dport; 425 } 426 xchg(nth->th_dport, nth->th_sport, n_short); 427 #undef xchg 428 } 429 #ifdef INET6 430 if (isipv6) { 431 ip6->ip6_flow = 0; 432 ip6->ip6_vfc = IPV6_VERSION; 433 ip6->ip6_nxt = IPPROTO_TCP; 434 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 435 tlen)); 436 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 437 } else 438 #endif 439 { 440 tlen += sizeof (struct tcpiphdr); 441 ip->ip_len = tlen; 442 ip->ip_ttl = ip_defttl; 443 } 444 m->m_len = tlen; 445 m->m_pkthdr.len = tlen; 446 m->m_pkthdr.rcvif = (struct ifnet *) 0; 447 nth->th_seq = htonl(seq); 448 nth->th_ack = htonl(ack); 449 nth->th_x2 = 0; 450 nth->th_off = sizeof (struct tcphdr) >> 2; 451 nth->th_flags = flags; 452 if (tp) 453 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 454 else 455 nth->th_win = htons((u_short)win); 456 nth->th_urp = 0; 457 #ifdef INET6 458 if (isipv6) { 459 nth->th_sum = 0; 460 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 461 sizeof(struct ip6_hdr), 462 tlen - sizeof(struct ip6_hdr)); 463 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 464 ro6 && ro6->ro_rt ? 465 ro6->ro_rt->rt_ifp : 466 NULL); 467 } else 468 #endif /* INET6 */ 469 { 470 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 471 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 472 m->m_pkthdr.csum_flags = CSUM_TCP; 473 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 474 } 475 #ifdef TCPDEBUG 476 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 477 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 478 #endif 479 #ifdef IPSEC 480 if (ipsec_setsocket(m, tp ? tp->t_inpcb->inp_socket : NULL) != 0) { 481 m_freem(m); 482 return; 483 } 484 #endif 485 #ifdef INET6 486 if (isipv6) { 487 (void)ip6_output(m, NULL, ro6, ipflags, NULL, NULL); 488 if (ro6 == &sro6 && ro6->ro_rt) { 489 RTFREE(ro6->ro_rt); 490 ro6->ro_rt = NULL; 491 } 492 } else 493 #endif /* INET6 */ 494 { 495 (void) ip_output(m, NULL, ro, ipflags, NULL); 496 if (ro == &sro && ro->ro_rt) { 497 RTFREE(ro->ro_rt); 498 ro->ro_rt = NULL; 499 } 500 } 501 } 502 503 /* 504 * Create a new TCP control block, making an 505 * empty reassembly queue and hooking it to the argument 506 * protocol control block. The `inp' parameter must have 507 * come from the zone allocator set up in tcp_init(). 508 */ 509 struct tcpcb * 510 tcp_newtcpcb(inp) 511 struct inpcb *inp; 512 { 513 struct inp_tp *it; 514 register struct tcpcb *tp; 515 #ifdef INET6 516 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 517 #endif /* INET6 */ 518 519 it = (struct inp_tp *)inp; 520 tp = &it->tcb; 521 bzero((char *) tp, sizeof(struct tcpcb)); 522 LIST_INIT(&tp->t_segq); 523 tp->t_maxseg = tp->t_maxopd = 524 #ifdef INET6 525 isipv6 ? tcp_v6mssdflt : 526 #endif /* INET6 */ 527 tcp_mssdflt; 528 529 /* Set up our timeouts. */ 530 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt, 0); 531 callout_init(tp->tt_persist = &it->inp_tp_persist, 0); 532 callout_init(tp->tt_keep = &it->inp_tp_keep, 0); 533 callout_init(tp->tt_2msl = &it->inp_tp_2msl, 0); 534 callout_init(tp->tt_delack = &it->inp_tp_delack, 0); 535 536 if (tcp_do_rfc1323) 537 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 538 if (tcp_do_rfc1644) 539 tp->t_flags |= TF_REQ_CC; 540 tp->t_inpcb = inp; /* XXX */ 541 /* 542 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 543 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 544 * reasonable initial retransmit time. 545 */ 546 tp->t_srtt = TCPTV_SRTTBASE; 547 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 548 tp->t_rttmin = TCPTV_MIN; 549 tp->t_rxtcur = TCPTV_RTOBASE; 550 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 551 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 552 tp->t_rcvtime = ticks; 553 /* 554 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 555 * because the socket may be bound to an IPv6 wildcard address, 556 * which may match an IPv4-mapped IPv6 address. 557 */ 558 inp->inp_ip_ttl = ip_defttl; 559 inp->inp_ppcb = (caddr_t)tp; 560 return (tp); /* XXX */ 561 } 562 563 /* 564 * Drop a TCP connection, reporting 565 * the specified error. If connection is synchronized, 566 * then send a RST to peer. 567 */ 568 struct tcpcb * 569 tcp_drop(tp, errno) 570 register struct tcpcb *tp; 571 int errno; 572 { 573 struct socket *so = tp->t_inpcb->inp_socket; 574 575 if (TCPS_HAVERCVDSYN(tp->t_state)) { 576 tp->t_state = TCPS_CLOSED; 577 (void) tcp_output(tp); 578 tcpstat.tcps_drops++; 579 } else 580 tcpstat.tcps_conndrops++; 581 if (errno == ETIMEDOUT && tp->t_softerror) 582 errno = tp->t_softerror; 583 so->so_error = errno; 584 return (tcp_close(tp)); 585 } 586 587 /* 588 * Close a TCP control block: 589 * discard all space held by the tcp 590 * discard internet protocol block 591 * wake up any sleepers 592 */ 593 struct tcpcb * 594 tcp_close(tp) 595 register struct tcpcb *tp; 596 { 597 register struct tseg_qent *q; 598 struct inpcb *inp = tp->t_inpcb; 599 struct socket *so = inp->inp_socket; 600 #ifdef INET6 601 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 602 #endif /* INET6 */ 603 register struct rtentry *rt; 604 int dosavessthresh; 605 606 /* 607 * Make sure that all of our timers are stopped before we 608 * delete the PCB. 609 */ 610 callout_stop(tp->tt_rexmt); 611 callout_stop(tp->tt_persist); 612 callout_stop(tp->tt_keep); 613 callout_stop(tp->tt_2msl); 614 callout_stop(tp->tt_delack); 615 616 /* 617 * If we got enough samples through the srtt filter, 618 * save the rtt and rttvar in the routing entry. 619 * 'Enough' is arbitrarily defined as the 16 samples. 620 * 16 samples is enough for the srtt filter to converge 621 * to within 5% of the correct value; fewer samples and 622 * we could save a very bogus rtt. 623 * 624 * Don't update the default route's characteristics and don't 625 * update anything that the user "locked". 626 */ 627 if (tp->t_rttupdated >= 16) { 628 register u_long i = 0; 629 #ifdef INET6 630 if (isipv6) { 631 struct sockaddr_in6 *sin6; 632 633 if ((rt = inp->in6p_route.ro_rt) == NULL) 634 goto no_valid_rt; 635 sin6 = (struct sockaddr_in6 *)rt_key(rt); 636 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 637 goto no_valid_rt; 638 } 639 else 640 #endif /* INET6 */ 641 if ((rt = inp->inp_route.ro_rt) == NULL || 642 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr 643 == INADDR_ANY) 644 goto no_valid_rt; 645 646 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 647 i = tp->t_srtt * 648 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 649 if (rt->rt_rmx.rmx_rtt && i) 650 /* 651 * filter this update to half the old & half 652 * the new values, converting scale. 653 * See route.h and tcp_var.h for a 654 * description of the scaling constants. 655 */ 656 rt->rt_rmx.rmx_rtt = 657 (rt->rt_rmx.rmx_rtt + i) / 2; 658 else 659 rt->rt_rmx.rmx_rtt = i; 660 tcpstat.tcps_cachedrtt++; 661 } 662 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 663 i = tp->t_rttvar * 664 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 665 if (rt->rt_rmx.rmx_rttvar && i) 666 rt->rt_rmx.rmx_rttvar = 667 (rt->rt_rmx.rmx_rttvar + i) / 2; 668 else 669 rt->rt_rmx.rmx_rttvar = i; 670 tcpstat.tcps_cachedrttvar++; 671 } 672 /* 673 * The old comment here said: 674 * update the pipelimit (ssthresh) if it has been updated 675 * already or if a pipesize was specified & the threshhold 676 * got below half the pipesize. I.e., wait for bad news 677 * before we start updating, then update on both good 678 * and bad news. 679 * 680 * But we want to save the ssthresh even if no pipesize is 681 * specified explicitly in the route, because such 682 * connections still have an implicit pipesize specified 683 * by the global tcp_sendspace. In the absence of a reliable 684 * way to calculate the pipesize, it will have to do. 685 */ 686 i = tp->snd_ssthresh; 687 if (rt->rt_rmx.rmx_sendpipe != 0) 688 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2); 689 else 690 dosavessthresh = (i < so->so_snd.sb_hiwat / 2); 691 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 692 i != 0 && rt->rt_rmx.rmx_ssthresh != 0) 693 || dosavessthresh) { 694 /* 695 * convert the limit from user data bytes to 696 * packets then to packet data bytes. 697 */ 698 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 699 if (i < 2) 700 i = 2; 701 i *= (u_long)(tp->t_maxseg + 702 #ifdef INET6 703 (isipv6 ? sizeof (struct ip6_hdr) + 704 sizeof (struct tcphdr) : 705 #endif 706 sizeof (struct tcpiphdr) 707 #ifdef INET6 708 ) 709 #endif 710 ); 711 if (rt->rt_rmx.rmx_ssthresh) 712 rt->rt_rmx.rmx_ssthresh = 713 (rt->rt_rmx.rmx_ssthresh + i) / 2; 714 else 715 rt->rt_rmx.rmx_ssthresh = i; 716 tcpstat.tcps_cachedssthresh++; 717 } 718 } 719 no_valid_rt: 720 /* free the reassembly queue, if any */ 721 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 722 LIST_REMOVE(q, tqe_q); 723 m_freem(q->tqe_m); 724 FREE(q, M_TSEGQ); 725 } 726 inp->inp_ppcb = NULL; 727 soisdisconnected(so); 728 #ifdef INET6 729 if (INP_CHECK_SOCKAF(so, AF_INET6)) 730 in6_pcbdetach(inp); 731 else 732 #endif /* INET6 */ 733 in_pcbdetach(inp); 734 tcpstat.tcps_closed++; 735 return ((struct tcpcb *)0); 736 } 737 738 void 739 tcp_drain() 740 { 741 if (do_tcpdrain) 742 { 743 struct inpcb *inpb; 744 struct tcpcb *tcpb; 745 struct tseg_qent *te; 746 747 /* 748 * Walk the tcpbs, if existing, and flush the reassembly queue, 749 * if there is one... 750 * XXX: The "Net/3" implementation doesn't imply that the TCP 751 * reassembly queue should be flushed, but in a situation 752 * where we're really low on mbufs, this is potentially 753 * usefull. 754 */ 755 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) { 756 if ((tcpb = intotcpcb(inpb))) { 757 while ((te = LIST_FIRST(&tcpb->t_segq)) 758 != NULL) { 759 LIST_REMOVE(te, tqe_q); 760 m_freem(te->tqe_m); 761 FREE(te, M_TSEGQ); 762 } 763 } 764 } 765 } 766 } 767 768 /* 769 * Notify a tcp user of an asynchronous error; 770 * store error as soft error, but wake up user 771 * (for now, won't do anything until can select for soft error). 772 * 773 * Do not wake up user since there currently is no mechanism for 774 * reporting soft errors (yet - a kqueue filter may be added). 775 */ 776 static void 777 tcp_notify(inp, error) 778 struct inpcb *inp; 779 int error; 780 { 781 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 782 783 /* 784 * Ignore some errors if we are hooked up. 785 * If connection hasn't completed, has retransmitted several times, 786 * and receives a second error, give up now. This is better 787 * than waiting a long time to establish a connection that 788 * can never complete. 789 */ 790 if (tp->t_state == TCPS_ESTABLISHED && 791 (error == EHOSTUNREACH || error == ENETUNREACH || 792 error == EHOSTDOWN)) { 793 return; 794 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 795 tp->t_softerror) 796 tcp_drop(tp, error); 797 else 798 tp->t_softerror = error; 799 #if 0 800 wakeup((caddr_t) &so->so_timeo); 801 sorwakeup(so); 802 sowwakeup(so); 803 #endif 804 } 805 806 static int 807 tcp_pcblist(SYSCTL_HANDLER_ARGS) 808 { 809 int error, i, n, s; 810 struct inpcb *inp, **inp_list; 811 inp_gen_t gencnt; 812 struct xinpgen xig; 813 814 /* 815 * The process of preparing the TCB list is too time-consuming and 816 * resource-intensive to repeat twice on every request. 817 */ 818 if (req->oldptr == 0) { 819 n = tcbinfo.ipi_count; 820 req->oldidx = 2 * (sizeof xig) 821 + (n + n/8) * sizeof(struct xtcpcb); 822 return 0; 823 } 824 825 if (req->newptr != 0) 826 return EPERM; 827 828 /* 829 * OK, now we're committed to doing something. 830 */ 831 s = splnet(); 832 gencnt = tcbinfo.ipi_gencnt; 833 n = tcbinfo.ipi_count; 834 splx(s); 835 836 xig.xig_len = sizeof xig; 837 xig.xig_count = n; 838 xig.xig_gen = gencnt; 839 xig.xig_sogen = so_gencnt; 840 error = SYSCTL_OUT(req, &xig, sizeof xig); 841 if (error) 842 return error; 843 844 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 845 if (inp_list == 0) 846 return ENOMEM; 847 848 s = splnet(); 849 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n; 850 inp = LIST_NEXT(inp, inp_list)) { 851 if (inp->inp_gencnt <= gencnt) { 852 if (cr_canseesocket(req->td->td_ucred, 853 inp->inp_socket)) 854 continue; 855 inp_list[i++] = inp; 856 } 857 } 858 splx(s); 859 n = i; 860 861 error = 0; 862 for (i = 0; i < n; i++) { 863 inp = inp_list[i]; 864 if (inp->inp_gencnt <= gencnt) { 865 struct xtcpcb xt; 866 caddr_t inp_ppcb; 867 xt.xt_len = sizeof xt; 868 /* XXX should avoid extra copy */ 869 bcopy(inp, &xt.xt_inp, sizeof *inp); 870 inp_ppcb = inp->inp_ppcb; 871 if (inp_ppcb != NULL) 872 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 873 else 874 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 875 if (inp->inp_socket) 876 sotoxsocket(inp->inp_socket, &xt.xt_socket); 877 error = SYSCTL_OUT(req, &xt, sizeof xt); 878 } 879 } 880 if (!error) { 881 /* 882 * Give the user an updated idea of our state. 883 * If the generation differs from what we told 884 * her before, she knows that something happened 885 * while we were processing this request, and it 886 * might be necessary to retry. 887 */ 888 s = splnet(); 889 xig.xig_gen = tcbinfo.ipi_gencnt; 890 xig.xig_sogen = so_gencnt; 891 xig.xig_count = tcbinfo.ipi_count; 892 splx(s); 893 error = SYSCTL_OUT(req, &xig, sizeof xig); 894 } 895 free(inp_list, M_TEMP); 896 return error; 897 } 898 899 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 900 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 901 902 static int 903 tcp_getcred(SYSCTL_HANDLER_ARGS) 904 { 905 struct xucred xuc; 906 struct sockaddr_in addrs[2]; 907 struct inpcb *inp; 908 int error, s; 909 910 error = suser_xxx(0, req->td->td_proc, PRISON_ROOT); 911 if (error) 912 return (error); 913 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 914 if (error) 915 return (error); 916 s = splnet(); 917 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 918 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 919 if (inp == NULL || inp->inp_socket == NULL) { 920 error = ENOENT; 921 goto out; 922 } 923 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 924 if (error) 925 goto out; 926 cru2x(inp->inp_socket->so_cred, &xuc); 927 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 928 out: 929 splx(s); 930 return (error); 931 } 932 933 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 934 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 935 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 936 937 #ifdef INET6 938 static int 939 tcp6_getcred(SYSCTL_HANDLER_ARGS) 940 { 941 struct xucred xuc; 942 struct sockaddr_in6 addrs[2]; 943 struct inpcb *inp; 944 int error, s, mapped = 0; 945 946 error = suser_xxx(0, req->td->td_proc, PRISON_ROOT); 947 if (error) 948 return (error); 949 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 950 if (error) 951 return (error); 952 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 953 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 954 mapped = 1; 955 else 956 return (EINVAL); 957 } 958 s = splnet(); 959 if (mapped == 1) 960 inp = in_pcblookup_hash(&tcbinfo, 961 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 962 addrs[1].sin6_port, 963 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 964 addrs[0].sin6_port, 965 0, NULL); 966 else 967 inp = in6_pcblookup_hash(&tcbinfo, &addrs[1].sin6_addr, 968 addrs[1].sin6_port, 969 &addrs[0].sin6_addr, addrs[0].sin6_port, 970 0, NULL); 971 if (inp == NULL || inp->inp_socket == NULL) { 972 error = ENOENT; 973 goto out; 974 } 975 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 976 if (error) 977 goto out; 978 cru2x(inp->inp_socket->so_cred, &xuc); 979 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 980 out: 981 splx(s); 982 return (error); 983 } 984 985 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 986 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 987 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 988 #endif 989 990 991 void 992 tcp_ctlinput(cmd, sa, vip) 993 int cmd; 994 struct sockaddr *sa; 995 void *vip; 996 { 997 struct ip *ip = vip; 998 struct tcphdr *th; 999 struct in_addr faddr; 1000 struct inpcb *inp; 1001 struct tcpcb *tp; 1002 void (*notify)(struct inpcb *, int) = tcp_notify; 1003 tcp_seq icmp_seq; 1004 int s; 1005 1006 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1007 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1008 return; 1009 1010 if (cmd == PRC_QUENCH) 1011 notify = tcp_quench; 1012 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1013 cmd == PRC_UNREACH_PORT) && ip) 1014 notify = tcp_drop_syn_sent; 1015 else if (cmd == PRC_MSGSIZE) 1016 notify = tcp_mtudisc; 1017 else if (PRC_IS_REDIRECT(cmd)) { 1018 ip = 0; 1019 notify = in_rtchange; 1020 } else if (cmd == PRC_HOSTDEAD) 1021 ip = 0; 1022 else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0) 1023 return; 1024 if (ip) { 1025 s = splnet(); 1026 th = (struct tcphdr *)((caddr_t)ip 1027 + (IP_VHL_HL(ip->ip_vhl) << 2)); 1028 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1029 ip->ip_src, th->th_sport, 0, NULL); 1030 if (inp != NULL && inp->inp_socket != NULL) { 1031 icmp_seq = htonl(th->th_seq); 1032 tp = intotcpcb(inp); 1033 if (SEQ_GEQ(icmp_seq, tp->snd_una) && 1034 SEQ_LT(icmp_seq, tp->snd_max)) 1035 (*notify)(inp, inetctlerrmap[cmd]); 1036 } else { 1037 struct in_conninfo inc; 1038 1039 inc.inc_fport = th->th_dport; 1040 inc.inc_lport = th->th_sport; 1041 inc.inc_faddr = faddr; 1042 inc.inc_laddr = ip->ip_src; 1043 #ifdef INET6 1044 inc.inc_isipv6 = 0; 1045 #endif 1046 syncache_unreach(&inc, th); 1047 } 1048 splx(s); 1049 } else 1050 in_pcbnotifyall(&tcb, faddr, inetctlerrmap[cmd], notify); 1051 } 1052 1053 #ifdef INET6 1054 void 1055 tcp6_ctlinput(cmd, sa, d) 1056 int cmd; 1057 struct sockaddr *sa; 1058 void *d; 1059 { 1060 struct tcphdr th; 1061 void (*notify)(struct inpcb *, int) = tcp_notify; 1062 struct ip6_hdr *ip6; 1063 struct mbuf *m; 1064 struct ip6ctlparam *ip6cp = NULL; 1065 const struct sockaddr_in6 *sa6_src = NULL; 1066 int off; 1067 struct tcp_portonly { 1068 u_int16_t th_sport; 1069 u_int16_t th_dport; 1070 } *thp; 1071 1072 if (sa->sa_family != AF_INET6 || 1073 sa->sa_len != sizeof(struct sockaddr_in6)) 1074 return; 1075 1076 if (cmd == PRC_QUENCH) 1077 notify = tcp_quench; 1078 else if (cmd == PRC_MSGSIZE) 1079 notify = tcp_mtudisc; 1080 else if (!PRC_IS_REDIRECT(cmd) && 1081 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1082 return; 1083 1084 /* if the parameter is from icmp6, decode it. */ 1085 if (d != NULL) { 1086 ip6cp = (struct ip6ctlparam *)d; 1087 m = ip6cp->ip6c_m; 1088 ip6 = ip6cp->ip6c_ip6; 1089 off = ip6cp->ip6c_off; 1090 sa6_src = ip6cp->ip6c_src; 1091 } else { 1092 m = NULL; 1093 ip6 = NULL; 1094 off = 0; /* fool gcc */ 1095 sa6_src = &sa6_any; 1096 } 1097 1098 if (ip6) { 1099 struct in_conninfo inc; 1100 /* 1101 * XXX: We assume that when IPV6 is non NULL, 1102 * M and OFF are valid. 1103 */ 1104 1105 /* check if we can safely examine src and dst ports */ 1106 if (m->m_pkthdr.len < off + sizeof(*thp)) 1107 return; 1108 1109 bzero(&th, sizeof(th)); 1110 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1111 1112 in6_pcbnotify(&tcb, sa, th.th_dport, 1113 (struct sockaddr *)ip6cp->ip6c_src, 1114 th.th_sport, cmd, notify); 1115 1116 inc.inc_fport = th.th_dport; 1117 inc.inc_lport = th.th_sport; 1118 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1119 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1120 inc.inc_isipv6 = 1; 1121 syncache_unreach(&inc, &th); 1122 } else 1123 in6_pcbnotify(&tcb, sa, 0, (const struct sockaddr *)sa6_src, 1124 0, cmd, notify); 1125 } 1126 #endif /* INET6 */ 1127 1128 1129 /* 1130 * Following is where TCP initial sequence number generation occurs. 1131 * 1132 * There are two places where we must use initial sequence numbers: 1133 * 1. In SYN-ACK packets. 1134 * 2. In SYN packets. 1135 * 1136 * The ISNs in SYN-ACK packets have no monotonicity requirement, 1137 * and should be as unpredictable as possible to avoid the possibility 1138 * of spoofing and/or connection hijacking. To satisfy this 1139 * requirement, SYN-ACK ISNs are generated via the arc4random() 1140 * function. If exact RFC 1948 compliance is requested via sysctl, 1141 * these ISNs will be generated just like those in SYN packets. 1142 * 1143 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1144 * depends on this property. In addition, these ISNs should be 1145 * unguessable so as to prevent connection hijacking. To satisfy 1146 * the requirements of this situation, the algorithm outlined in 1147 * RFC 1948 is used to generate sequence numbers. 1148 * 1149 * For more information on the theory of operation, please see 1150 * RFC 1948. 1151 * 1152 * Implementation details: 1153 * 1154 * Time is based off the system timer, and is corrected so that it 1155 * increases by one megabyte per second. This allows for proper 1156 * recycling on high speed LANs while still leaving over an hour 1157 * before rollover. 1158 * 1159 * Two sysctls control the generation of ISNs: 1160 * 1161 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1162 * between seeding of isn_secret. This is normally set to zero, 1163 * as reseeding should not be necessary. 1164 * 1165 * net.inet.tcp.strict_rfc1948 controls whether RFC 1948 is followed 1166 * strictly. When strict compliance is requested, reseeding is 1167 * disabled and SYN-ACKs will be generated in the same manner as 1168 * SYNs. Strict mode is disabled by default. 1169 * 1170 */ 1171 1172 #define ISN_BYTES_PER_SECOND 1048576 1173 1174 u_char isn_secret[32]; 1175 int isn_last_reseed; 1176 MD5_CTX isn_ctx; 1177 1178 tcp_seq 1179 tcp_new_isn(tp) 1180 struct tcpcb *tp; 1181 { 1182 u_int32_t md5_buffer[4]; 1183 tcp_seq new_isn; 1184 1185 /* Use arc4random for SYN-ACKs when not in exact RFC1948 mode. */ 1186 if (((tp->t_state == TCPS_LISTEN) || (tp->t_state == TCPS_TIME_WAIT)) 1187 && tcp_strict_rfc1948 == 0) 1188 return arc4random(); 1189 1190 /* Seed if this is the first use, reseed if requested. */ 1191 if ((isn_last_reseed == 0) || 1192 ((tcp_strict_rfc1948 == 0) && (tcp_isn_reseed_interval > 0) && 1193 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1194 < (u_int)ticks))) { 1195 read_random(&isn_secret, sizeof(isn_secret)); 1196 isn_last_reseed = ticks; 1197 } 1198 1199 /* Compute the md5 hash and return the ISN. */ 1200 MD5Init(&isn_ctx); 1201 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1202 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1203 #ifdef INET6 1204 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1205 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1206 sizeof(struct in6_addr)); 1207 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1208 sizeof(struct in6_addr)); 1209 } else 1210 #endif 1211 { 1212 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1213 sizeof(struct in_addr)); 1214 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1215 sizeof(struct in_addr)); 1216 } 1217 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1218 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1219 new_isn = (tcp_seq) md5_buffer[0]; 1220 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1221 return new_isn; 1222 } 1223 1224 /* 1225 * When a source quench is received, close congestion window 1226 * to one segment. We will gradually open it again as we proceed. 1227 */ 1228 void 1229 tcp_quench(inp, errno) 1230 struct inpcb *inp; 1231 int errno; 1232 { 1233 struct tcpcb *tp = intotcpcb(inp); 1234 1235 if (tp) 1236 tp->snd_cwnd = tp->t_maxseg; 1237 } 1238 1239 /* 1240 * When a specific ICMP unreachable message is received and the 1241 * connection state is SYN-SENT, drop the connection. This behavior 1242 * is controlled by the icmp_may_rst sysctl. 1243 */ 1244 void 1245 tcp_drop_syn_sent(inp, errno) 1246 struct inpcb *inp; 1247 int errno; 1248 { 1249 struct tcpcb *tp = intotcpcb(inp); 1250 1251 if (tp && tp->t_state == TCPS_SYN_SENT) 1252 tcp_drop(tp, errno); 1253 } 1254 1255 /* 1256 * When `need fragmentation' ICMP is received, update our idea of the MSS 1257 * based on the new value in the route. Also nudge TCP to send something, 1258 * since we know the packet we just sent was dropped. 1259 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1260 */ 1261 void 1262 tcp_mtudisc(inp, errno) 1263 struct inpcb *inp; 1264 int errno; 1265 { 1266 struct tcpcb *tp = intotcpcb(inp); 1267 struct rtentry *rt; 1268 struct rmxp_tao *taop; 1269 struct socket *so = inp->inp_socket; 1270 int offered; 1271 int mss; 1272 #ifdef INET6 1273 int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1274 #endif /* INET6 */ 1275 1276 if (tp) { 1277 #ifdef INET6 1278 if (isipv6) 1279 rt = tcp_rtlookup6(&inp->inp_inc); 1280 else 1281 #endif /* INET6 */ 1282 rt = tcp_rtlookup(&inp->inp_inc); 1283 if (!rt || !rt->rt_rmx.rmx_mtu) { 1284 tp->t_maxopd = tp->t_maxseg = 1285 #ifdef INET6 1286 isipv6 ? tcp_v6mssdflt : 1287 #endif /* INET6 */ 1288 tcp_mssdflt; 1289 return; 1290 } 1291 taop = rmx_taop(rt->rt_rmx); 1292 offered = taop->tao_mssopt; 1293 mss = rt->rt_rmx.rmx_mtu - 1294 #ifdef INET6 1295 (isipv6 ? 1296 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1297 #endif /* INET6 */ 1298 sizeof(struct tcpiphdr) 1299 #ifdef INET6 1300 ) 1301 #endif /* INET6 */ 1302 ; 1303 1304 if (offered) 1305 mss = min(mss, offered); 1306 /* 1307 * XXX - The above conditional probably violates the TCP 1308 * spec. The problem is that, since we don't know the 1309 * other end's MSS, we are supposed to use a conservative 1310 * default. But, if we do that, then MTU discovery will 1311 * never actually take place, because the conservative 1312 * default is much less than the MTUs typically seen 1313 * on the Internet today. For the moment, we'll sweep 1314 * this under the carpet. 1315 * 1316 * The conservative default might not actually be a problem 1317 * if the only case this occurs is when sending an initial 1318 * SYN with options and data to a host we've never talked 1319 * to before. Then, they will reply with an MSS value which 1320 * will get recorded and the new parameters should get 1321 * recomputed. For Further Study. 1322 */ 1323 if (tp->t_maxopd <= mss) 1324 return; 1325 tp->t_maxopd = mss; 1326 1327 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1328 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1329 mss -= TCPOLEN_TSTAMP_APPA; 1330 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC && 1331 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC) 1332 mss -= TCPOLEN_CC_APPA; 1333 #if (MCLBYTES & (MCLBYTES - 1)) == 0 1334 if (mss > MCLBYTES) 1335 mss &= ~(MCLBYTES-1); 1336 #else 1337 if (mss > MCLBYTES) 1338 mss = mss / MCLBYTES * MCLBYTES; 1339 #endif 1340 if (so->so_snd.sb_hiwat < mss) 1341 mss = so->so_snd.sb_hiwat; 1342 1343 tp->t_maxseg = mss; 1344 1345 tcpstat.tcps_mturesent++; 1346 tp->t_rtttime = 0; 1347 tp->snd_nxt = tp->snd_una; 1348 tcp_output(tp); 1349 } 1350 } 1351 1352 /* 1353 * Look-up the routing entry to the peer of this inpcb. If no route 1354 * is found and it cannot be allocated the return NULL. This routine 1355 * is called by TCP routines that access the rmx structure and by tcp_mss 1356 * to get the interface MTU. 1357 */ 1358 struct rtentry * 1359 tcp_rtlookup(inc) 1360 struct in_conninfo *inc; 1361 { 1362 struct route *ro; 1363 struct rtentry *rt; 1364 1365 ro = &inc->inc_route; 1366 rt = ro->ro_rt; 1367 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1368 /* No route yet, so try to acquire one */ 1369 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1370 ro->ro_dst.sa_family = AF_INET; 1371 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1372 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1373 inc->inc_faddr; 1374 rtalloc(ro); 1375 rt = ro->ro_rt; 1376 } 1377 } 1378 return rt; 1379 } 1380 1381 #ifdef INET6 1382 struct rtentry * 1383 tcp_rtlookup6(inc) 1384 struct in_conninfo *inc; 1385 { 1386 struct route_in6 *ro6; 1387 struct rtentry *rt; 1388 1389 ro6 = &inc->inc6_route; 1390 rt = ro6->ro_rt; 1391 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1392 /* No route yet, so try to acquire one */ 1393 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1394 ro6->ro_dst.sin6_family = AF_INET6; 1395 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1396 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1397 rtalloc((struct route *)ro6); 1398 rt = ro6->ro_rt; 1399 } 1400 } 1401 return rt; 1402 } 1403 #endif /* INET6 */ 1404 1405 #ifdef IPSEC 1406 /* compute ESP/AH header size for TCP, including outer IP header. */ 1407 size_t 1408 ipsec_hdrsiz_tcp(tp) 1409 struct tcpcb *tp; 1410 { 1411 struct inpcb *inp; 1412 struct mbuf *m; 1413 size_t hdrsiz; 1414 struct ip *ip; 1415 #ifdef INET6 1416 struct ip6_hdr *ip6; 1417 #endif /* INET6 */ 1418 struct tcphdr *th; 1419 1420 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1421 return 0; 1422 MGETHDR(m, M_DONTWAIT, MT_DATA); 1423 if (!m) 1424 return 0; 1425 1426 #ifdef INET6 1427 if ((inp->inp_vflag & INP_IPV6) != 0) { 1428 ip6 = mtod(m, struct ip6_hdr *); 1429 th = (struct tcphdr *)(ip6 + 1); 1430 m->m_pkthdr.len = m->m_len = 1431 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1432 tcp_fillheaders(tp, ip6, th); 1433 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1434 } else 1435 #endif /* INET6 */ 1436 { 1437 ip = mtod(m, struct ip *); 1438 th = (struct tcphdr *)(ip + 1); 1439 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1440 tcp_fillheaders(tp, ip, th); 1441 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1442 } 1443 1444 m_free(m); 1445 return hdrsiz; 1446 } 1447 #endif /*IPSEC*/ 1448 1449 /* 1450 * Return a pointer to the cached information about the remote host. 1451 * The cached information is stored in the protocol specific part of 1452 * the route metrics. 1453 */ 1454 struct rmxp_tao * 1455 tcp_gettaocache(inc) 1456 struct in_conninfo *inc; 1457 { 1458 struct rtentry *rt; 1459 1460 #ifdef INET6 1461 if (inc->inc_isipv6) 1462 rt = tcp_rtlookup6(inc); 1463 else 1464 #endif /* INET6 */ 1465 rt = tcp_rtlookup(inc); 1466 1467 /* Make sure this is a host route and is up. */ 1468 if (rt == NULL || 1469 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)) 1470 return NULL; 1471 1472 return rmx_taop(rt->rt_rmx); 1473 } 1474 1475 /* 1476 * Clear all the TAO cache entries, called from tcp_init. 1477 * 1478 * XXX 1479 * This routine is just an empty one, because we assume that the routing 1480 * routing tables are initialized at the same time when TCP, so there is 1481 * nothing in the cache left over. 1482 */ 1483 static void 1484 tcp_cleartaocache() 1485 { 1486 } 1487