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/vm_zone.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 static 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 static 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 __P((void)); 152 static void tcp_notify __P((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 = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 216 ZONE_INTERRUPT, 0); 217 #ifdef INET6 218 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 219 #else /* INET6 */ 220 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 221 #endif /* INET6 */ 222 if (max_protohdr < TCP_MINPROTOHDR) 223 max_protohdr = TCP_MINPROTOHDR; 224 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 225 panic("tcp_init"); 226 #undef TCP_MINPROTOHDR 227 } 228 229 /* 230 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 231 * tcp_template used to store this data in mbufs, but we now recopy it out 232 * of the tcpcb each time to conserve mbufs. 233 */ 234 void 235 tcp_fillheaders(tp, ip_ptr, tcp_ptr) 236 struct tcpcb *tp; 237 void *ip_ptr; 238 void *tcp_ptr; 239 { 240 struct inpcb *inp = tp->t_inpcb; 241 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 242 243 #ifdef INET6 244 if ((inp->inp_vflag & INP_IPV6) != 0) { 245 struct ip6_hdr *ip6; 246 247 ip6 = (struct ip6_hdr *)ip_ptr; 248 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 249 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 250 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 251 (IPV6_VERSION & IPV6_VERSION_MASK); 252 ip6->ip6_nxt = IPPROTO_TCP; 253 ip6->ip6_plen = sizeof(struct tcphdr); 254 ip6->ip6_src = inp->in6p_laddr; 255 ip6->ip6_dst = inp->in6p_faddr; 256 tcp_hdr->th_sum = 0; 257 } else 258 #endif 259 { 260 struct ip *ip = (struct ip *) ip_ptr; 261 262 ip->ip_vhl = IP_VHL_BORING; 263 ip->ip_tos = 0; 264 ip->ip_len = 0; 265 ip->ip_id = 0; 266 ip->ip_off = 0; 267 ip->ip_ttl = 0; 268 ip->ip_sum = 0; 269 ip->ip_p = IPPROTO_TCP; 270 ip->ip_src = inp->inp_laddr; 271 ip->ip_dst = inp->inp_faddr; 272 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 273 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 274 } 275 276 tcp_hdr->th_sport = inp->inp_lport; 277 tcp_hdr->th_dport = inp->inp_fport; 278 tcp_hdr->th_seq = 0; 279 tcp_hdr->th_ack = 0; 280 tcp_hdr->th_x2 = 0; 281 tcp_hdr->th_off = 5; 282 tcp_hdr->th_flags = 0; 283 tcp_hdr->th_win = 0; 284 tcp_hdr->th_urp = 0; 285 } 286 287 /* 288 * Create template to be used to send tcp packets on a connection. 289 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 290 * use for this function is in keepalives, which use tcp_respond. 291 */ 292 struct tcptemp * 293 tcp_maketemplate(tp) 294 struct tcpcb *tp; 295 { 296 struct mbuf *m; 297 struct tcptemp *n; 298 299 m = m_get(M_DONTWAIT, MT_HEADER); 300 if (m == NULL) 301 return (0); 302 m->m_len = sizeof(struct tcptemp); 303 n = mtod(m, struct tcptemp *); 304 305 tcp_fillheaders(tp, (void *)&n->tt_ipgen, (void *)&n->tt_t); 306 return (n); 307 } 308 309 /* 310 * Send a single message to the TCP at address specified by 311 * the given TCP/IP header. If m == 0, then we make a copy 312 * of the tcpiphdr at ti and send directly to the addressed host. 313 * This is used to force keep alive messages out using the TCP 314 * template for a connection. If flags are given then we send 315 * a message back to the TCP which originated the * segment ti, 316 * and discard the mbuf containing it and any other attached mbufs. 317 * 318 * In any case the ack and sequence number of the transmitted 319 * segment are as specified by the parameters. 320 * 321 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 322 */ 323 void 324 tcp_respond(tp, ipgen, th, m, ack, seq, flags) 325 struct tcpcb *tp; 326 void *ipgen; 327 register struct tcphdr *th; 328 register struct mbuf *m; 329 tcp_seq ack, seq; 330 int flags; 331 { 332 register int tlen; 333 int win = 0; 334 struct route *ro = 0; 335 struct route sro; 336 struct ip *ip; 337 struct tcphdr *nth; 338 #ifdef INET6 339 struct route_in6 *ro6 = 0; 340 struct route_in6 sro6; 341 struct ip6_hdr *ip6; 342 int isipv6; 343 #endif /* INET6 */ 344 int ipflags = 0; 345 346 #ifdef INET6 347 isipv6 = IP_VHL_V(((struct ip *)ipgen)->ip_vhl) == 6; 348 ip6 = ipgen; 349 #endif /* INET6 */ 350 ip = ipgen; 351 352 if (tp) { 353 if (!(flags & TH_RST)) { 354 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 355 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 356 win = (long)TCP_MAXWIN << tp->rcv_scale; 357 } 358 #ifdef INET6 359 if (isipv6) 360 ro6 = &tp->t_inpcb->in6p_route; 361 else 362 #endif /* INET6 */ 363 ro = &tp->t_inpcb->inp_route; 364 } else { 365 #ifdef INET6 366 if (isipv6) { 367 ro6 = &sro6; 368 bzero(ro6, sizeof *ro6); 369 } else 370 #endif /* INET6 */ 371 { 372 ro = &sro; 373 bzero(ro, sizeof *ro); 374 } 375 } 376 if (m == 0) { 377 m = m_gethdr(M_DONTWAIT, MT_HEADER); 378 if (m == NULL) 379 return; 380 tlen = 0; 381 m->m_data += max_linkhdr; 382 #ifdef INET6 383 if (isipv6) { 384 bcopy((caddr_t)ip6, mtod(m, caddr_t), 385 sizeof(struct ip6_hdr)); 386 ip6 = mtod(m, struct ip6_hdr *); 387 nth = (struct tcphdr *)(ip6 + 1); 388 } else 389 #endif /* INET6 */ 390 { 391 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 392 ip = mtod(m, struct ip *); 393 nth = (struct tcphdr *)(ip + 1); 394 } 395 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 396 flags = TH_ACK; 397 } else { 398 m_freem(m->m_next); 399 m->m_next = 0; 400 m->m_data = (caddr_t)ipgen; 401 /* m_len is set later */ 402 tlen = 0; 403 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 404 #ifdef INET6 405 if (isipv6) { 406 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 407 nth = (struct tcphdr *)(ip6 + 1); 408 } else 409 #endif /* INET6 */ 410 { 411 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 412 nth = (struct tcphdr *)(ip + 1); 413 } 414 if (th != nth) { 415 /* 416 * this is usually a case when an extension header 417 * exists between the IPv6 header and the 418 * TCP header. 419 */ 420 nth->th_sport = th->th_sport; 421 nth->th_dport = th->th_dport; 422 } 423 xchg(nth->th_dport, nth->th_sport, n_short); 424 #undef xchg 425 } 426 #ifdef INET6 427 if (isipv6) { 428 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 429 tlen)); 430 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 431 } else 432 #endif 433 { 434 tlen += sizeof (struct tcpiphdr); 435 ip->ip_len = tlen; 436 ip->ip_ttl = ip_defttl; 437 } 438 m->m_len = tlen; 439 m->m_pkthdr.len = tlen; 440 m->m_pkthdr.rcvif = (struct ifnet *) 0; 441 nth->th_seq = htonl(seq); 442 nth->th_ack = htonl(ack); 443 nth->th_x2 = 0; 444 nth->th_off = sizeof (struct tcphdr) >> 2; 445 nth->th_flags = flags; 446 if (tp) 447 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 448 else 449 nth->th_win = htons((u_short)win); 450 nth->th_urp = 0; 451 #ifdef INET6 452 if (isipv6) { 453 nth->th_sum = 0; 454 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 455 sizeof(struct ip6_hdr), 456 tlen - sizeof(struct ip6_hdr)); 457 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 458 ro6 && ro6->ro_rt ? 459 ro6->ro_rt->rt_ifp : 460 NULL); 461 } else 462 #endif /* INET6 */ 463 { 464 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 465 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 466 m->m_pkthdr.csum_flags = CSUM_TCP; 467 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 468 } 469 #ifdef TCPDEBUG 470 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 471 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 472 #endif 473 #ifdef IPSEC 474 if (ipsec_setsocket(m, tp ? tp->t_inpcb->inp_socket : NULL) != 0) { 475 m_freem(m); 476 return; 477 } 478 #endif 479 #ifdef INET6 480 if (isipv6) { 481 (void)ip6_output(m, NULL, ro6, ipflags, NULL, NULL); 482 if (ro6 == &sro6 && ro6->ro_rt) { 483 RTFREE(ro6->ro_rt); 484 ro6->ro_rt = NULL; 485 } 486 } else 487 #endif /* INET6 */ 488 { 489 (void) ip_output(m, NULL, ro, ipflags, NULL); 490 if (ro == &sro && ro->ro_rt) { 491 RTFREE(ro->ro_rt); 492 ro->ro_rt = NULL; 493 } 494 } 495 } 496 497 /* 498 * Create a new TCP control block, making an 499 * empty reassembly queue and hooking it to the argument 500 * protocol control block. The `inp' parameter must have 501 * come from the zone allocator set up in tcp_init(). 502 */ 503 struct tcpcb * 504 tcp_newtcpcb(inp) 505 struct inpcb *inp; 506 { 507 struct inp_tp *it; 508 register struct tcpcb *tp; 509 #ifdef INET6 510 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 511 #endif /* INET6 */ 512 513 it = (struct inp_tp *)inp; 514 tp = &it->tcb; 515 bzero((char *) tp, sizeof(struct tcpcb)); 516 LIST_INIT(&tp->t_segq); 517 tp->t_maxseg = tp->t_maxopd = 518 #ifdef INET6 519 isipv6 ? tcp_v6mssdflt : 520 #endif /* INET6 */ 521 tcp_mssdflt; 522 523 /* Set up our timeouts. */ 524 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt, 0); 525 callout_init(tp->tt_persist = &it->inp_tp_persist, 0); 526 callout_init(tp->tt_keep = &it->inp_tp_keep, 0); 527 callout_init(tp->tt_2msl = &it->inp_tp_2msl, 0); 528 callout_init(tp->tt_delack = &it->inp_tp_delack, 0); 529 530 if (tcp_do_rfc1323) 531 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 532 if (tcp_do_rfc1644) 533 tp->t_flags |= TF_REQ_CC; 534 tp->t_inpcb = inp; /* XXX */ 535 /* 536 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 537 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 538 * reasonable initial retransmit time. 539 */ 540 tp->t_srtt = TCPTV_SRTTBASE; 541 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 542 tp->t_rttmin = TCPTV_MIN; 543 tp->t_rxtcur = TCPTV_RTOBASE; 544 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 545 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 546 tp->t_rcvtime = ticks; 547 /* 548 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 549 * because the socket may be bound to an IPv6 wildcard address, 550 * which may match an IPv4-mapped IPv6 address. 551 */ 552 inp->inp_ip_ttl = ip_defttl; 553 inp->inp_ppcb = (caddr_t)tp; 554 return (tp); /* XXX */ 555 } 556 557 /* 558 * Drop a TCP connection, reporting 559 * the specified error. If connection is synchronized, 560 * then send a RST to peer. 561 */ 562 struct tcpcb * 563 tcp_drop(tp, errno) 564 register struct tcpcb *tp; 565 int errno; 566 { 567 struct socket *so = tp->t_inpcb->inp_socket; 568 569 if (TCPS_HAVERCVDSYN(tp->t_state)) { 570 tp->t_state = TCPS_CLOSED; 571 (void) tcp_output(tp); 572 tcpstat.tcps_drops++; 573 } else 574 tcpstat.tcps_conndrops++; 575 if (errno == ETIMEDOUT && tp->t_softerror) 576 errno = tp->t_softerror; 577 so->so_error = errno; 578 return (tcp_close(tp)); 579 } 580 581 /* 582 * Close a TCP control block: 583 * discard all space held by the tcp 584 * discard internet protocol block 585 * wake up any sleepers 586 */ 587 struct tcpcb * 588 tcp_close(tp) 589 register struct tcpcb *tp; 590 { 591 register struct tseg_qent *q; 592 struct inpcb *inp = tp->t_inpcb; 593 struct socket *so = inp->inp_socket; 594 #ifdef INET6 595 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 596 #endif /* INET6 */ 597 register struct rtentry *rt; 598 int dosavessthresh; 599 600 /* 601 * Make sure that all of our timers are stopped before we 602 * delete the PCB. 603 */ 604 callout_stop(tp->tt_rexmt); 605 callout_stop(tp->tt_persist); 606 callout_stop(tp->tt_keep); 607 callout_stop(tp->tt_2msl); 608 callout_stop(tp->tt_delack); 609 610 /* 611 * If we got enough samples through the srtt filter, 612 * save the rtt and rttvar in the routing entry. 613 * 'Enough' is arbitrarily defined as the 16 samples. 614 * 16 samples is enough for the srtt filter to converge 615 * to within 5% of the correct value; fewer samples and 616 * we could save a very bogus rtt. 617 * 618 * Don't update the default route's characteristics and don't 619 * update anything that the user "locked". 620 */ 621 if (tp->t_rttupdated >= 16) { 622 register u_long i = 0; 623 #ifdef INET6 624 if (isipv6) { 625 struct sockaddr_in6 *sin6; 626 627 if ((rt = inp->in6p_route.ro_rt) == NULL) 628 goto no_valid_rt; 629 sin6 = (struct sockaddr_in6 *)rt_key(rt); 630 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 631 goto no_valid_rt; 632 } 633 else 634 #endif /* INET6 */ 635 if ((rt = inp->inp_route.ro_rt) == NULL || 636 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr 637 == INADDR_ANY) 638 goto no_valid_rt; 639 640 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 641 i = tp->t_srtt * 642 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 643 if (rt->rt_rmx.rmx_rtt && i) 644 /* 645 * filter this update to half the old & half 646 * the new values, converting scale. 647 * See route.h and tcp_var.h for a 648 * description of the scaling constants. 649 */ 650 rt->rt_rmx.rmx_rtt = 651 (rt->rt_rmx.rmx_rtt + i) / 2; 652 else 653 rt->rt_rmx.rmx_rtt = i; 654 tcpstat.tcps_cachedrtt++; 655 } 656 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 657 i = tp->t_rttvar * 658 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 659 if (rt->rt_rmx.rmx_rttvar && i) 660 rt->rt_rmx.rmx_rttvar = 661 (rt->rt_rmx.rmx_rttvar + i) / 2; 662 else 663 rt->rt_rmx.rmx_rttvar = i; 664 tcpstat.tcps_cachedrttvar++; 665 } 666 /* 667 * The old comment here said: 668 * update the pipelimit (ssthresh) if it has been updated 669 * already or if a pipesize was specified & the threshhold 670 * got below half the pipesize. I.e., wait for bad news 671 * before we start updating, then update on both good 672 * and bad news. 673 * 674 * But we want to save the ssthresh even if no pipesize is 675 * specified explicitly in the route, because such 676 * connections still have an implicit pipesize specified 677 * by the global tcp_sendspace. In the absence of a reliable 678 * way to calculate the pipesize, it will have to do. 679 */ 680 i = tp->snd_ssthresh; 681 if (rt->rt_rmx.rmx_sendpipe != 0) 682 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2); 683 else 684 dosavessthresh = (i < so->so_snd.sb_hiwat / 2); 685 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 686 i != 0 && rt->rt_rmx.rmx_ssthresh != 0) 687 || dosavessthresh) { 688 /* 689 * convert the limit from user data bytes to 690 * packets then to packet data bytes. 691 */ 692 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 693 if (i < 2) 694 i = 2; 695 i *= (u_long)(tp->t_maxseg + 696 #ifdef INET6 697 (isipv6 ? sizeof (struct ip6_hdr) + 698 sizeof (struct tcphdr) : 699 #endif 700 sizeof (struct tcpiphdr) 701 #ifdef INET6 702 ) 703 #endif 704 ); 705 if (rt->rt_rmx.rmx_ssthresh) 706 rt->rt_rmx.rmx_ssthresh = 707 (rt->rt_rmx.rmx_ssthresh + i) / 2; 708 else 709 rt->rt_rmx.rmx_ssthresh = i; 710 tcpstat.tcps_cachedssthresh++; 711 } 712 } 713 rt = inp->inp_route.ro_rt; 714 if (rt) { 715 /* 716 * mark route for deletion if no information is 717 * cached. 718 */ 719 if ((tp->t_flags & TF_LQ_OVERFLOW) && 720 ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0)){ 721 if (rt->rt_rmx.rmx_rtt == 0) 722 rt->rt_flags |= RTF_DELCLONE; 723 } 724 } 725 no_valid_rt: 726 /* free the reassembly queue, if any */ 727 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 728 LIST_REMOVE(q, tqe_q); 729 m_freem(q->tqe_m); 730 FREE(q, M_TSEGQ); 731 } 732 inp->inp_ppcb = NULL; 733 soisdisconnected(so); 734 #ifdef INET6 735 if (INP_CHECK_SOCKAF(so, AF_INET6)) 736 in6_pcbdetach(inp); 737 else 738 #endif /* INET6 */ 739 in_pcbdetach(inp); 740 tcpstat.tcps_closed++; 741 return ((struct tcpcb *)0); 742 } 743 744 void 745 tcp_drain() 746 { 747 if (do_tcpdrain) 748 { 749 struct inpcb *inpb; 750 struct tcpcb *tcpb; 751 struct tseg_qent *te; 752 753 /* 754 * Walk the tcpbs, if existing, and flush the reassembly queue, 755 * if there is one... 756 * XXX: The "Net/3" implementation doesn't imply that the TCP 757 * reassembly queue should be flushed, but in a situation 758 * where we're really low on mbufs, this is potentially 759 * usefull. 760 */ 761 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) { 762 if ((tcpb = intotcpcb(inpb))) { 763 while ((te = LIST_FIRST(&tcpb->t_segq)) 764 != NULL) { 765 LIST_REMOVE(te, tqe_q); 766 m_freem(te->tqe_m); 767 FREE(te, M_TSEGQ); 768 } 769 } 770 } 771 } 772 } 773 774 /* 775 * Notify a tcp user of an asynchronous error; 776 * store error as soft error, but wake up user 777 * (for now, won't do anything until can select for soft error). 778 * 779 * Do not wake up user since there currently is no mechanism for 780 * reporting soft errors (yet - a kqueue filter may be added). 781 */ 782 static void 783 tcp_notify(inp, error) 784 struct inpcb *inp; 785 int error; 786 { 787 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 788 789 /* 790 * Ignore some errors if we are hooked up. 791 * If connection hasn't completed, has retransmitted several times, 792 * and receives a second error, give up now. This is better 793 * than waiting a long time to establish a connection that 794 * can never complete. 795 */ 796 if (tp->t_state == TCPS_ESTABLISHED && 797 (error == EHOSTUNREACH || error == ENETUNREACH || 798 error == EHOSTDOWN)) { 799 return; 800 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 801 tp->t_softerror) 802 tcp_drop(tp, error); 803 else 804 tp->t_softerror = error; 805 #if 0 806 wakeup((caddr_t) &so->so_timeo); 807 sorwakeup(so); 808 sowwakeup(so); 809 #endif 810 } 811 812 static int 813 tcp_pcblist(SYSCTL_HANDLER_ARGS) 814 { 815 int error, i, n, s; 816 struct inpcb *inp, **inp_list; 817 inp_gen_t gencnt; 818 struct xinpgen xig; 819 820 /* 821 * The process of preparing the TCB list is too time-consuming and 822 * resource-intensive to repeat twice on every request. 823 */ 824 if (req->oldptr == 0) { 825 n = tcbinfo.ipi_count; 826 req->oldidx = 2 * (sizeof xig) 827 + (n + n/8) * sizeof(struct xtcpcb); 828 return 0; 829 } 830 831 if (req->newptr != 0) 832 return EPERM; 833 834 /* 835 * OK, now we're committed to doing something. 836 */ 837 s = splnet(); 838 gencnt = tcbinfo.ipi_gencnt; 839 n = tcbinfo.ipi_count; 840 splx(s); 841 842 xig.xig_len = sizeof xig; 843 xig.xig_count = n; 844 xig.xig_gen = gencnt; 845 xig.xig_sogen = so_gencnt; 846 error = SYSCTL_OUT(req, &xig, sizeof xig); 847 if (error) 848 return error; 849 850 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 851 if (inp_list == 0) 852 return ENOMEM; 853 854 s = splnet(); 855 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n; 856 inp = LIST_NEXT(inp, inp_list)) { 857 if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->p, inp)) 858 inp_list[i++] = inp; 859 } 860 splx(s); 861 n = i; 862 863 error = 0; 864 for (i = 0; i < n; i++) { 865 inp = inp_list[i]; 866 if (inp->inp_gencnt <= gencnt) { 867 struct xtcpcb xt; 868 caddr_t inp_ppcb; 869 xt.xt_len = sizeof xt; 870 /* XXX should avoid extra copy */ 871 bcopy(inp, &xt.xt_inp, sizeof *inp); 872 inp_ppcb = inp->inp_ppcb; 873 if (inp_ppcb != NULL) 874 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 875 else 876 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 877 if (inp->inp_socket) 878 sotoxsocket(inp->inp_socket, &xt.xt_socket); 879 error = SYSCTL_OUT(req, &xt, sizeof xt); 880 } 881 } 882 if (!error) { 883 /* 884 * Give the user an updated idea of our state. 885 * If the generation differs from what we told 886 * her before, she knows that something happened 887 * while we were processing this request, and it 888 * might be necessary to retry. 889 */ 890 s = splnet(); 891 xig.xig_gen = tcbinfo.ipi_gencnt; 892 xig.xig_sogen = so_gencnt; 893 xig.xig_count = tcbinfo.ipi_count; 894 splx(s); 895 error = SYSCTL_OUT(req, &xig, sizeof xig); 896 } 897 free(inp_list, M_TEMP); 898 return error; 899 } 900 901 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 902 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 903 904 static int 905 tcp_getcred(SYSCTL_HANDLER_ARGS) 906 { 907 struct xucred xuc; 908 struct sockaddr_in addrs[2]; 909 struct inpcb *inp; 910 int error, s; 911 912 error = suser_xxx(0, req->p, PRISON_ROOT); 913 if (error) 914 return (error); 915 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 916 if (error) 917 return (error); 918 s = splnet(); 919 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 920 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 921 if (inp == NULL || inp->inp_socket == NULL) { 922 error = ENOENT; 923 goto out; 924 } 925 error = u_cansee(req->p->p_ucred, inp->inp_socket->so_cred); 926 if (error) 927 goto out; 928 bzero(&xuc, sizeof(xuc)); 929 xuc.cr_uid = inp->inp_socket->so_cred->cr_uid; 930 xuc.cr_ngroups = inp->inp_socket->so_cred->cr_ngroups; 931 bcopy(inp->inp_socket->so_cred->cr_groups, xuc.cr_groups, 932 sizeof(xuc.cr_groups)); 933 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 934 out: 935 splx(s); 936 return (error); 937 } 938 939 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 940 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 941 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 942 943 #ifdef INET6 944 static int 945 tcp6_getcred(SYSCTL_HANDLER_ARGS) 946 { 947 struct xucred xuc; 948 struct sockaddr_in6 addrs[2]; 949 struct inpcb *inp; 950 int error, s, mapped = 0; 951 952 error = suser_xxx(0, req->p, PRISON_ROOT); 953 if (error) 954 return (error); 955 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 956 if (error) 957 return (error); 958 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 959 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 960 mapped = 1; 961 else 962 return (EINVAL); 963 } 964 s = splnet(); 965 if (mapped == 1) 966 inp = in_pcblookup_hash(&tcbinfo, 967 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 968 addrs[1].sin6_port, 969 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 970 addrs[0].sin6_port, 971 0, NULL); 972 else 973 inp = in6_pcblookup_hash(&tcbinfo, &addrs[1].sin6_addr, 974 addrs[1].sin6_port, 975 &addrs[0].sin6_addr, addrs[0].sin6_port, 976 0, NULL); 977 if (inp == NULL || inp->inp_socket == NULL) { 978 error = ENOENT; 979 goto out; 980 } 981 error = u_cansee(req->p->p_ucred, inp->inp_socket->so_cred); 982 if (error) 983 goto out; 984 bzero(&xuc, sizeof(xuc)); 985 xuc.cr_uid = inp->inp_socket->so_cred->cr_uid; 986 xuc.cr_ngroups = inp->inp_socket->so_cred->cr_ngroups; 987 bcopy(inp->inp_socket->so_cred->cr_groups, xuc.cr_groups, 988 sizeof(xuc.cr_groups)); 989 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 990 out: 991 splx(s); 992 return (error); 993 } 994 995 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 996 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 997 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 998 #endif 999 1000 1001 void 1002 tcp_ctlinput(cmd, sa, vip) 1003 int cmd; 1004 struct sockaddr *sa; 1005 void *vip; 1006 { 1007 struct ip *ip = vip; 1008 struct tcphdr *th; 1009 struct in_addr faddr; 1010 struct inpcb *inp; 1011 struct tcpcb *tp; 1012 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1013 tcp_seq icmp_seq; 1014 int s; 1015 1016 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1017 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1018 return; 1019 1020 if (cmd == PRC_QUENCH) 1021 notify = tcp_quench; 1022 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1023 cmd == PRC_UNREACH_PORT) && ip) 1024 notify = tcp_drop_syn_sent; 1025 else if (cmd == PRC_MSGSIZE) 1026 notify = tcp_mtudisc; 1027 else if (PRC_IS_REDIRECT(cmd)) { 1028 ip = 0; 1029 notify = in_rtchange; 1030 } else if (cmd == PRC_HOSTDEAD) 1031 ip = 0; 1032 else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0) 1033 return; 1034 if (ip) { 1035 s = splnet(); 1036 th = (struct tcphdr *)((caddr_t)ip 1037 + (IP_VHL_HL(ip->ip_vhl) << 2)); 1038 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1039 ip->ip_src, th->th_sport, 0, NULL); 1040 if (inp != NULL && inp->inp_socket != NULL) { 1041 icmp_seq = htonl(th->th_seq); 1042 tp = intotcpcb(inp); 1043 if (SEQ_GEQ(icmp_seq, tp->snd_una) && 1044 SEQ_LT(icmp_seq, tp->snd_max)) 1045 (*notify)(inp, inetctlerrmap[cmd]); 1046 } 1047 splx(s); 1048 } else 1049 in_pcbnotifyall(&tcb, faddr, inetctlerrmap[cmd], notify); 1050 } 1051 1052 #ifdef INET6 1053 void 1054 tcp6_ctlinput(cmd, sa, d) 1055 int cmd; 1056 struct sockaddr *sa; 1057 void *d; 1058 { 1059 struct tcphdr th; 1060 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 1061 struct ip6_hdr *ip6; 1062 struct mbuf *m; 1063 struct ip6ctlparam *ip6cp = NULL; 1064 const struct sockaddr_in6 *sa6_src = NULL; 1065 int off; 1066 struct tcp_portonly { 1067 u_int16_t th_sport; 1068 u_int16_t th_dport; 1069 } *thp; 1070 1071 if (sa->sa_family != AF_INET6 || 1072 sa->sa_len != sizeof(struct sockaddr_in6)) 1073 return; 1074 1075 if (cmd == PRC_QUENCH) 1076 notify = tcp_quench; 1077 else if (cmd == PRC_MSGSIZE) 1078 notify = tcp_mtudisc; 1079 else if (!PRC_IS_REDIRECT(cmd) && 1080 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1081 return; 1082 1083 /* if the parameter is from icmp6, decode it. */ 1084 if (d != NULL) { 1085 ip6cp = (struct ip6ctlparam *)d; 1086 m = ip6cp->ip6c_m; 1087 ip6 = ip6cp->ip6c_ip6; 1088 off = ip6cp->ip6c_off; 1089 sa6_src = ip6cp->ip6c_src; 1090 } else { 1091 m = NULL; 1092 ip6 = NULL; 1093 off = 0; /* fool gcc */ 1094 sa6_src = &sa6_any; 1095 } 1096 1097 if (ip6) { 1098 /* 1099 * XXX: We assume that when IPV6 is non NULL, 1100 * M and OFF are valid. 1101 */ 1102 1103 /* check if we can safely examine src and dst ports */ 1104 if (m->m_pkthdr.len < off + sizeof(*thp)) 1105 return; 1106 1107 bzero(&th, sizeof(th)); 1108 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1109 1110 in6_pcbnotify(&tcb, sa, th.th_dport, 1111 (struct sockaddr *)ip6cp->ip6c_src, 1112 th.th_sport, cmd, notify); 1113 } else 1114 in6_pcbnotify(&tcb, sa, 0, (struct sockaddr *)sa6_src, 1115 0, cmd, notify); 1116 } 1117 #endif /* INET6 */ 1118 1119 1120 /* 1121 * Following is where TCP initial sequence number generation occurs. 1122 * 1123 * There are two places where we must use initial sequence numbers: 1124 * 1. In SYN-ACK packets. 1125 * 2. In SYN packets. 1126 * 1127 * The ISNs in SYN-ACK packets have no monotonicity requirement, 1128 * and should be as unpredictable as possible to avoid the possibility 1129 * of spoofing and/or connection hijacking. To satisfy this 1130 * requirement, SYN-ACK ISNs are generated via the arc4random() 1131 * function. If exact RFC 1948 compliance is requested via sysctl, 1132 * these ISNs will be generated just like those in SYN packets. 1133 * 1134 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1135 * depends on this property. In addition, these ISNs should be 1136 * unguessable so as to prevent connection hijacking. To satisfy 1137 * the requirements of this situation, the algorithm outlined in 1138 * RFC 1948 is used to generate sequence numbers. 1139 * 1140 * For more information on the theory of operation, please see 1141 * RFC 1948. 1142 * 1143 * Implementation details: 1144 * 1145 * Time is based off the system timer, and is corrected so that it 1146 * increases by one megabyte per second. This allows for proper 1147 * recycling on high speed LANs while still leaving over an hour 1148 * before rollover. 1149 * 1150 * Two sysctls control the generation of ISNs: 1151 * 1152 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1153 * between seeding of isn_secret. This is normally set to zero, 1154 * as reseeding should not be necessary. 1155 * 1156 * net.inet.tcp.strict_rfc1948 controls whether RFC 1948 is followed 1157 * strictly. When strict compliance is requested, reseeding is 1158 * disabled and SYN-ACKs will be generated in the same manner as 1159 * SYNs. Strict mode is disabled by default. 1160 * 1161 */ 1162 1163 #define ISN_BYTES_PER_SECOND 1048576 1164 1165 u_char isn_secret[32]; 1166 int isn_last_reseed; 1167 MD5_CTX isn_ctx; 1168 1169 tcp_seq 1170 tcp_new_isn(tp) 1171 struct tcpcb *tp; 1172 { 1173 u_int32_t md5_buffer[4]; 1174 tcp_seq new_isn; 1175 1176 /* Use arc4random for SYN-ACKs when not in exact RFC1948 mode. */ 1177 if (((tp->t_state == TCPS_LISTEN) || (tp->t_state == TCPS_TIME_WAIT)) 1178 && tcp_strict_rfc1948 == 0) 1179 return arc4random(); 1180 1181 /* Seed if this is the first use, reseed if requested. */ 1182 if ((isn_last_reseed == 0) || 1183 ((tcp_strict_rfc1948 == 0) && (tcp_isn_reseed_interval > 0) && 1184 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1185 < (u_int)ticks))) { 1186 read_random(&isn_secret, sizeof(isn_secret)); 1187 isn_last_reseed = ticks; 1188 } 1189 1190 /* Compute the md5 hash and return the ISN. */ 1191 MD5Init(&isn_ctx); 1192 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1193 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1194 #ifdef INET6 1195 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1196 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1197 sizeof(struct in6_addr)); 1198 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1199 sizeof(struct in6_addr)); 1200 } else 1201 #endif 1202 { 1203 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1204 sizeof(struct in_addr)); 1205 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1206 sizeof(struct in_addr)); 1207 } 1208 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1209 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1210 new_isn = (tcp_seq) md5_buffer[0]; 1211 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1212 return new_isn; 1213 } 1214 1215 /* 1216 * When a source quench is received, close congestion window 1217 * to one segment. We will gradually open it again as we proceed. 1218 */ 1219 void 1220 tcp_quench(inp, errno) 1221 struct inpcb *inp; 1222 int errno; 1223 { 1224 struct tcpcb *tp = intotcpcb(inp); 1225 1226 if (tp) 1227 tp->snd_cwnd = tp->t_maxseg; 1228 } 1229 1230 /* 1231 * When a specific ICMP unreachable message is received and the 1232 * connection state is SYN-SENT, drop the connection. This behavior 1233 * is controlled by the icmp_may_rst sysctl. 1234 */ 1235 void 1236 tcp_drop_syn_sent(inp, errno) 1237 struct inpcb *inp; 1238 int errno; 1239 { 1240 struct tcpcb *tp = intotcpcb(inp); 1241 1242 if (tp && tp->t_state == TCPS_SYN_SENT) 1243 tcp_drop(tp, errno); 1244 } 1245 1246 /* 1247 * When `need fragmentation' ICMP is received, update our idea of the MSS 1248 * based on the new value in the route. Also nudge TCP to send something, 1249 * since we know the packet we just sent was dropped. 1250 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1251 */ 1252 void 1253 tcp_mtudisc(inp, errno) 1254 struct inpcb *inp; 1255 int errno; 1256 { 1257 struct tcpcb *tp = intotcpcb(inp); 1258 struct rtentry *rt; 1259 struct rmxp_tao *taop; 1260 struct socket *so = inp->inp_socket; 1261 int offered; 1262 int mss; 1263 #ifdef INET6 1264 int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1265 #endif /* INET6 */ 1266 1267 if (tp) { 1268 #ifdef INET6 1269 if (isipv6) 1270 rt = tcp_rtlookup6(inp); 1271 else 1272 #endif /* INET6 */ 1273 rt = tcp_rtlookup(inp); 1274 if (!rt || !rt->rt_rmx.rmx_mtu) { 1275 tp->t_maxopd = tp->t_maxseg = 1276 #ifdef INET6 1277 isipv6 ? tcp_v6mssdflt : 1278 #endif /* INET6 */ 1279 tcp_mssdflt; 1280 return; 1281 } 1282 taop = rmx_taop(rt->rt_rmx); 1283 offered = taop->tao_mssopt; 1284 mss = rt->rt_rmx.rmx_mtu - 1285 #ifdef INET6 1286 (isipv6 ? 1287 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1288 #endif /* INET6 */ 1289 sizeof(struct tcpiphdr) 1290 #ifdef INET6 1291 ) 1292 #endif /* INET6 */ 1293 ; 1294 1295 if (offered) 1296 mss = min(mss, offered); 1297 /* 1298 * XXX - The above conditional probably violates the TCP 1299 * spec. The problem is that, since we don't know the 1300 * other end's MSS, we are supposed to use a conservative 1301 * default. But, if we do that, then MTU discovery will 1302 * never actually take place, because the conservative 1303 * default is much less than the MTUs typically seen 1304 * on the Internet today. For the moment, we'll sweep 1305 * this under the carpet. 1306 * 1307 * The conservative default might not actually be a problem 1308 * if the only case this occurs is when sending an initial 1309 * SYN with options and data to a host we've never talked 1310 * to before. Then, they will reply with an MSS value which 1311 * will get recorded and the new parameters should get 1312 * recomputed. For Further Study. 1313 */ 1314 if (tp->t_maxopd <= mss) 1315 return; 1316 tp->t_maxopd = mss; 1317 1318 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1319 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1320 mss -= TCPOLEN_TSTAMP_APPA; 1321 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC && 1322 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC) 1323 mss -= TCPOLEN_CC_APPA; 1324 #if (MCLBYTES & (MCLBYTES - 1)) == 0 1325 if (mss > MCLBYTES) 1326 mss &= ~(MCLBYTES-1); 1327 #else 1328 if (mss > MCLBYTES) 1329 mss = mss / MCLBYTES * MCLBYTES; 1330 #endif 1331 if (so->so_snd.sb_hiwat < mss) 1332 mss = so->so_snd.sb_hiwat; 1333 1334 tp->t_maxseg = mss; 1335 1336 tcpstat.tcps_mturesent++; 1337 tp->t_rtttime = 0; 1338 tp->snd_nxt = tp->snd_una; 1339 tcp_output(tp); 1340 } 1341 } 1342 1343 /* 1344 * Look-up the routing entry to the peer of this inpcb. If no route 1345 * is found and it cannot be allocated the return NULL. This routine 1346 * is called by TCP routines that access the rmx structure and by tcp_mss 1347 * to get the interface MTU. 1348 */ 1349 struct rtentry * 1350 tcp_rtlookup(inp) 1351 struct inpcb *inp; 1352 { 1353 struct route *ro; 1354 struct rtentry *rt; 1355 1356 ro = &inp->inp_route; 1357 rt = ro->ro_rt; 1358 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1359 /* No route yet, so try to acquire one */ 1360 if (inp->inp_faddr.s_addr != INADDR_ANY) { 1361 ro->ro_dst.sa_family = AF_INET; 1362 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1363 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1364 inp->inp_faddr; 1365 rtalloc(ro); 1366 rt = ro->ro_rt; 1367 } 1368 } 1369 return rt; 1370 } 1371 1372 #ifdef INET6 1373 struct rtentry * 1374 tcp_rtlookup6(inp) 1375 struct inpcb *inp; 1376 { 1377 struct route_in6 *ro6; 1378 struct rtentry *rt; 1379 1380 ro6 = &inp->in6p_route; 1381 rt = ro6->ro_rt; 1382 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1383 /* No route yet, so try to acquire one */ 1384 if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) { 1385 struct sockaddr_in6 *dst6; 1386 1387 dst6 = (struct sockaddr_in6 *)&ro6->ro_dst; 1388 dst6->sin6_family = AF_INET6; 1389 dst6->sin6_len = sizeof(*dst6); 1390 dst6->sin6_addr = inp->in6p_faddr; 1391 rtalloc((struct route *)ro6); 1392 rt = ro6->ro_rt; 1393 } 1394 } 1395 return rt; 1396 } 1397 #endif /* INET6 */ 1398 1399 #ifdef IPSEC 1400 /* compute ESP/AH header size for TCP, including outer IP header. */ 1401 size_t 1402 ipsec_hdrsiz_tcp(tp) 1403 struct tcpcb *tp; 1404 { 1405 struct inpcb *inp; 1406 struct mbuf *m; 1407 size_t hdrsiz; 1408 struct ip *ip; 1409 #ifdef INET6 1410 struct ip6_hdr *ip6; 1411 #endif /* INET6 */ 1412 struct tcphdr *th; 1413 1414 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1415 return 0; 1416 MGETHDR(m, M_DONTWAIT, MT_DATA); 1417 if (!m) 1418 return 0; 1419 1420 #ifdef INET6 1421 if ((inp->inp_vflag & INP_IPV6) != 0) { 1422 ip6 = mtod(m, struct ip6_hdr *); 1423 th = (struct tcphdr *)(ip6 + 1); 1424 m->m_pkthdr.len = m->m_len = 1425 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1426 tcp_fillheaders(tp, ip6, th); 1427 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1428 } else 1429 #endif /* INET6 */ 1430 { 1431 ip = mtod(m, struct ip *); 1432 th = (struct tcphdr *)(ip + 1); 1433 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1434 tcp_fillheaders(tp, ip, th); 1435 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1436 } 1437 1438 m_free(m); 1439 return hdrsiz; 1440 } 1441 #endif /*IPSEC*/ 1442 1443 /* 1444 * Return a pointer to the cached information about the remote host. 1445 * The cached information is stored in the protocol specific part of 1446 * the route metrics. 1447 */ 1448 struct rmxp_tao * 1449 tcp_gettaocache(inp) 1450 struct inpcb *inp; 1451 { 1452 struct rtentry *rt; 1453 1454 #ifdef INET6 1455 if ((inp->inp_vflag & INP_IPV6) != 0) 1456 rt = tcp_rtlookup6(inp); 1457 else 1458 #endif /* INET6 */ 1459 rt = tcp_rtlookup(inp); 1460 1461 /* Make sure this is a host route and is up. */ 1462 if (rt == NULL || 1463 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)) 1464 return NULL; 1465 1466 return rmx_taop(rt->rt_rmx); 1467 } 1468 1469 /* 1470 * Clear all the TAO cache entries, called from tcp_init. 1471 * 1472 * XXX 1473 * This routine is just an empty one, because we assume that the routing 1474 * routing tables are initialized at the same time when TCP, so there is 1475 * nothing in the cache left over. 1476 */ 1477 static void 1478 tcp_cleartaocache() 1479 { 1480 } 1481