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: src/sys/netinet/tcp_subr.c,v 1.73.2.31 2003/01/24 05:11:34 sam Exp $ 35 * $DragonFly: src/sys/netinet/tcp_subr.c,v 1.17 2004/03/14 08:26:31 hsu Exp $ 36 */ 37 38 #include "opt_compat.h" 39 #include "opt_inet6.h" 40 #include "opt_ipsec.h" 41 #include "opt_tcpdebug.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/callout.h> 46 #include <sys/kernel.h> 47 #include <sys/sysctl.h> 48 #include <sys/malloc.h> 49 #include <sys/mbuf.h> 50 #ifdef INET6 51 #include <sys/domain.h> 52 #endif 53 #include <sys/proc.h> 54 #include <sys/socket.h> 55 #include <sys/socketvar.h> 56 #include <sys/protosw.h> 57 #include <sys/random.h> 58 #include <sys/in_cksum.h> 59 60 #include <vm/vm_zone.h> 61 62 #include <net/route.h> 63 #include <net/if.h> 64 #include <net/netisr.h> 65 66 #define _IP_VHL 67 #include <netinet/in.h> 68 #include <netinet/in_systm.h> 69 #include <netinet/ip.h> 70 #ifdef INET6 71 #include <netinet/ip6.h> 72 #endif 73 #include <netinet/in_pcb.h> 74 #ifdef INET6 75 #include <netinet6/in6_pcb.h> 76 #endif 77 #include <netinet/in_var.h> 78 #include <netinet/ip_var.h> 79 #ifdef INET6 80 #include <netinet6/ip6_var.h> 81 #endif 82 #include <netinet/tcp.h> 83 #include <netinet/tcp_fsm.h> 84 #include <netinet/tcp_seq.h> 85 #include <netinet/tcp_timer.h> 86 #include <netinet/tcp_var.h> 87 #ifdef INET6 88 #include <netinet6/tcp6_var.h> 89 #endif 90 #include <netinet/tcpip.h> 91 #ifdef TCPDEBUG 92 #include <netinet/tcp_debug.h> 93 #endif 94 #include <netinet6/ip6protosw.h> 95 96 #ifdef IPSEC 97 #include <netinet6/ipsec.h> 98 #ifdef INET6 99 #include <netinet6/ipsec6.h> 100 #endif 101 #endif /*IPSEC*/ 102 103 #ifdef FAST_IPSEC 104 #include <netipsec/ipsec.h> 105 #ifdef INET6 106 #include <netipsec/ipsec6.h> 107 #endif 108 #define IPSEC 109 #endif /*FAST_IPSEC*/ 110 111 #include <sys/md5.h> 112 113 #include <sys/msgport2.h> 114 115 int tcp_mssdflt = TCP_MSS; 116 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 117 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size"); 118 119 #ifdef INET6 120 int tcp_v6mssdflt = TCP6_MSS; 121 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 122 CTLFLAG_RW, &tcp_v6mssdflt , 0, 123 "Default TCP Maximum Segment Size for IPv6"); 124 #endif 125 126 #if 0 127 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 128 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 129 &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time"); 130 #endif 131 132 int tcp_do_rfc1323 = 1; 133 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 134 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions"); 135 136 int tcp_do_rfc1644 = 0; 137 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 138 &tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions"); 139 140 static int tcp_tcbhashsize = 0; 141 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 142 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 143 144 static int do_tcpdrain = 1; 145 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 146 "Enable tcp_drain routine for extra help when low on mbufs"); 147 148 /* XXX JH */ 149 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 150 &tcbinfo[0].ipi_count, 0, "Number of active PCBs"); 151 152 static int icmp_may_rst = 1; 153 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 154 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 155 156 static int tcp_isn_reseed_interval = 0; 157 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 158 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 159 160 /* 161 * TCP bandwidth limiting sysctls. Note that the default lower bound of 162 * 1024 exists only for debugging. A good production default would be 163 * something like 6100. 164 */ 165 static int tcp_inflight_enable = 0; 166 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW, 167 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 168 169 static int tcp_inflight_debug = 0; 170 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW, 171 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 172 173 static int tcp_inflight_min = 6144; 174 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW, 175 &tcp_inflight_min, 0, "Lower-bound for TCP inflight window"); 176 177 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 178 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW, 179 &tcp_inflight_max, 0, "Upper-bound for TCP inflight window"); 180 181 static int tcp_inflight_stab = 20; 182 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW, 183 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 2 packets)"); 184 185 static void tcp_cleartaocache (void); 186 static void tcp_notify (struct inpcb *, int); 187 188 /* 189 * Target size of TCP PCB hash tables. Must be a power of two. 190 * 191 * Note that this can be overridden by the kernel environment 192 * variable net.inet.tcp.tcbhashsize 193 */ 194 #ifndef TCBHASHSIZE 195 #define TCBHASHSIZE 512 196 #endif 197 198 /* 199 * This is the actual shape of what we allocate using the zone 200 * allocator. Doing it this way allows us to protect both structures 201 * using the same generation count, and also eliminates the overhead 202 * of allocating tcpcbs separately. By hiding the structure here, 203 * we avoid changing most of the rest of the code (although it needs 204 * to be changed, eventually, for greater efficiency). 205 */ 206 #define ALIGNMENT 32 207 #define ALIGNM1 (ALIGNMENT - 1) 208 struct inp_tp { 209 union { 210 struct inpcb inp; 211 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 212 } inp_tp_u; 213 struct tcpcb tcb; 214 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl; 215 struct callout inp_tp_delack; 216 }; 217 #undef ALIGNMENT 218 #undef ALIGNM1 219 220 /* 221 * Tcp initialization 222 */ 223 void 224 tcp_init() 225 { 226 struct inpcbporthead *porthashbase; 227 u_long porthashmask; 228 struct inpcbhead *bindhashbase; 229 u_long bindhashmask; 230 struct vm_zone *ipi_zone; 231 int hashsize = TCBHASHSIZE; 232 int cpu; 233 234 tcp_ccgen = 1; 235 tcp_cleartaocache(); 236 237 tcp_delacktime = TCPTV_DELACK; 238 tcp_keepinit = TCPTV_KEEP_INIT; 239 tcp_keepidle = TCPTV_KEEP_IDLE; 240 tcp_keepintvl = TCPTV_KEEPINTVL; 241 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 242 tcp_msl = TCPTV_MSL; 243 tcp_rexmit_min = TCPTV_MIN; 244 tcp_rexmit_slop = TCPTV_CPU_VAR; 245 246 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 247 if (!powerof2(hashsize)) { 248 printf("WARNING: TCB hash size not a power of 2\n"); 249 hashsize = 512; /* safe default */ 250 } 251 tcp_tcbhashsize = hashsize; 252 porthashbase = hashinit(hashsize, M_PCB, &porthashmask); 253 bindhashbase = hashinit(hashsize, M_PCB, &bindhashmask); 254 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 255 ZONE_INTERRUPT, 0); 256 257 for (cpu = 0; cpu < ncpus2; cpu++) { 258 LIST_INIT(&tcbinfo[cpu].listhead); 259 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB, 260 &tcbinfo[cpu].hashmask); 261 tcbinfo[cpu].porthashbase = porthashbase; 262 tcbinfo[cpu].porthashmask = porthashmask; 263 tcbinfo[cpu].bindhashbase = bindhashbase; 264 tcbinfo[cpu].bindhashmask = bindhashmask; 265 tcbinfo[cpu].ipi_zone = ipi_zone; 266 } 267 268 tcp_reass_maxseg = nmbclusters / 16; 269 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", 270 &tcp_reass_maxseg); 271 272 #ifdef INET6 273 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 274 #else /* INET6 */ 275 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 276 #endif /* INET6 */ 277 if (max_protohdr < TCP_MINPROTOHDR) 278 max_protohdr = TCP_MINPROTOHDR; 279 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 280 panic("tcp_init"); 281 #undef TCP_MINPROTOHDR 282 283 syncache_init(); 284 tcp_thread_init(); 285 } 286 287 /* 288 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 289 * tcp_template used to store this data in mbufs, but we now recopy it out 290 * of the tcpcb each time to conserve mbufs. 291 */ 292 void 293 tcp_fillheaders(tp, ip_ptr, tcp_ptr) 294 struct tcpcb *tp; 295 void *ip_ptr; 296 void *tcp_ptr; 297 { 298 struct inpcb *inp = tp->t_inpcb; 299 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 300 301 #ifdef INET6 302 if ((inp->inp_vflag & INP_IPV6) != 0) { 303 struct ip6_hdr *ip6; 304 305 ip6 = (struct ip6_hdr *)ip_ptr; 306 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 307 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 308 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 309 (IPV6_VERSION & IPV6_VERSION_MASK); 310 ip6->ip6_nxt = IPPROTO_TCP; 311 ip6->ip6_plen = sizeof(struct tcphdr); 312 ip6->ip6_src = inp->in6p_laddr; 313 ip6->ip6_dst = inp->in6p_faddr; 314 tcp_hdr->th_sum = 0; 315 } else 316 #endif 317 { 318 struct ip *ip = (struct ip *) ip_ptr; 319 320 ip->ip_vhl = IP_VHL_BORING; 321 ip->ip_tos = 0; 322 ip->ip_len = 0; 323 ip->ip_id = 0; 324 ip->ip_off = 0; 325 ip->ip_ttl = 0; 326 ip->ip_sum = 0; 327 ip->ip_p = IPPROTO_TCP; 328 ip->ip_src = inp->inp_laddr; 329 ip->ip_dst = inp->inp_faddr; 330 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 331 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 332 } 333 334 tcp_hdr->th_sport = inp->inp_lport; 335 tcp_hdr->th_dport = inp->inp_fport; 336 tcp_hdr->th_seq = 0; 337 tcp_hdr->th_ack = 0; 338 tcp_hdr->th_x2 = 0; 339 tcp_hdr->th_off = 5; 340 tcp_hdr->th_flags = 0; 341 tcp_hdr->th_win = 0; 342 tcp_hdr->th_urp = 0; 343 } 344 345 /* 346 * Create template to be used to send tcp packets on a connection. 347 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 348 * use for this function is in keepalives, which use tcp_respond. 349 */ 350 struct tcptemp * 351 tcp_maketemplate(tp) 352 struct tcpcb *tp; 353 { 354 struct mbuf *m; 355 struct tcptemp *n; 356 357 m = m_get(M_DONTWAIT, MT_HEADER); 358 if (m == NULL) 359 return (0); 360 m->m_len = sizeof(struct tcptemp); 361 n = mtod(m, struct tcptemp *); 362 363 tcp_fillheaders(tp, (void *)&n->tt_ipgen, (void *)&n->tt_t); 364 return (n); 365 } 366 367 /* 368 * Send a single message to the TCP at address specified by 369 * the given TCP/IP header. If m == 0, then we make a copy 370 * of the tcpiphdr at ti and send directly to the addressed host. 371 * This is used to force keep alive messages out using the TCP 372 * template for a connection. If flags are given then we send 373 * a message back to the TCP which originated the * segment ti, 374 * and discard the mbuf containing it and any other attached mbufs. 375 * 376 * In any case the ack and sequence number of the transmitted 377 * segment are as specified by the parameters. 378 * 379 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 380 */ 381 void 382 tcp_respond(tp, ipgen, th, m, ack, seq, flags) 383 struct tcpcb *tp; 384 void *ipgen; 385 struct tcphdr *th; 386 struct mbuf *m; 387 tcp_seq ack, seq; 388 int flags; 389 { 390 int tlen; 391 int win = 0; 392 struct route *ro = 0; 393 struct route sro; 394 struct ip *ip; 395 struct tcphdr *nth; 396 #ifdef INET6 397 struct route_in6 *ro6 = 0; 398 struct route_in6 sro6; 399 struct ip6_hdr *ip6; 400 int isipv6; 401 #endif /* INET6 */ 402 int ipflags = 0; 403 404 #ifdef INET6 405 isipv6 = IP_VHL_V(((struct ip *)ipgen)->ip_vhl) == 6; 406 ip6 = ipgen; 407 #endif /* INET6 */ 408 ip = ipgen; 409 410 if (tp) { 411 if (!(flags & TH_RST)) { 412 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 413 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 414 win = (long)TCP_MAXWIN << tp->rcv_scale; 415 } 416 #ifdef INET6 417 if (isipv6) 418 ro6 = &tp->t_inpcb->in6p_route; 419 else 420 #endif /* INET6 */ 421 ro = &tp->t_inpcb->inp_route; 422 } else { 423 #ifdef INET6 424 if (isipv6) { 425 ro6 = &sro6; 426 bzero(ro6, sizeof *ro6); 427 } else 428 #endif /* INET6 */ 429 { 430 ro = &sro; 431 bzero(ro, sizeof *ro); 432 } 433 } 434 if (m == 0) { 435 m = m_gethdr(M_DONTWAIT, MT_HEADER); 436 if (m == NULL) 437 return; 438 tlen = 0; 439 m->m_data += max_linkhdr; 440 #ifdef INET6 441 if (isipv6) { 442 bcopy((caddr_t)ip6, mtod(m, caddr_t), 443 sizeof(struct ip6_hdr)); 444 ip6 = mtod(m, struct ip6_hdr *); 445 nth = (struct tcphdr *)(ip6 + 1); 446 } else 447 #endif /* INET6 */ 448 { 449 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 450 ip = mtod(m, struct ip *); 451 nth = (struct tcphdr *)(ip + 1); 452 } 453 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 454 flags = TH_ACK; 455 } else { 456 m_freem(m->m_next); 457 m->m_next = 0; 458 m->m_data = (caddr_t)ipgen; 459 /* m_len is set later */ 460 tlen = 0; 461 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 462 #ifdef INET6 463 if (isipv6) { 464 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 465 nth = (struct tcphdr *)(ip6 + 1); 466 } else 467 #endif /* INET6 */ 468 { 469 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 470 nth = (struct tcphdr *)(ip + 1); 471 } 472 if (th != nth) { 473 /* 474 * this is usually a case when an extension header 475 * exists between the IPv6 header and the 476 * TCP header. 477 */ 478 nth->th_sport = th->th_sport; 479 nth->th_dport = th->th_dport; 480 } 481 xchg(nth->th_dport, nth->th_sport, n_short); 482 #undef xchg 483 } 484 #ifdef INET6 485 if (isipv6) { 486 ip6->ip6_flow = 0; 487 ip6->ip6_vfc = IPV6_VERSION; 488 ip6->ip6_nxt = IPPROTO_TCP; 489 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 490 tlen)); 491 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 492 } else 493 #endif 494 { 495 tlen += sizeof (struct tcpiphdr); 496 ip->ip_len = tlen; 497 ip->ip_ttl = ip_defttl; 498 } 499 m->m_len = tlen; 500 m->m_pkthdr.len = tlen; 501 m->m_pkthdr.rcvif = (struct ifnet *) 0; 502 nth->th_seq = htonl(seq); 503 nth->th_ack = htonl(ack); 504 nth->th_x2 = 0; 505 nth->th_off = sizeof (struct tcphdr) >> 2; 506 nth->th_flags = flags; 507 if (tp) 508 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 509 else 510 nth->th_win = htons((u_short)win); 511 nth->th_urp = 0; 512 #ifdef INET6 513 if (isipv6) { 514 nth->th_sum = 0; 515 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 516 sizeof(struct ip6_hdr), 517 tlen - sizeof(struct ip6_hdr)); 518 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 519 ro6 && ro6->ro_rt ? 520 ro6->ro_rt->rt_ifp : 521 NULL); 522 } else 523 #endif /* INET6 */ 524 { 525 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 526 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 527 m->m_pkthdr.csum_flags = CSUM_TCP; 528 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 529 } 530 #ifdef TCPDEBUG 531 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 532 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 533 #endif 534 #ifdef INET6 535 if (isipv6) { 536 (void)ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 537 tp ? tp->t_inpcb : NULL); 538 if (ro6 == &sro6 && ro6->ro_rt) { 539 RTFREE(ro6->ro_rt); 540 ro6->ro_rt = NULL; 541 } 542 } else 543 #endif /* INET6 */ 544 { 545 (void) ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 546 if (ro == &sro && ro->ro_rt) { 547 RTFREE(ro->ro_rt); 548 ro->ro_rt = NULL; 549 } 550 } 551 } 552 553 /* 554 * Create a new TCP control block, making an 555 * empty reassembly queue and hooking it to the argument 556 * protocol control block. The `inp' parameter must have 557 * come from the zone allocator set up in tcp_init(). 558 */ 559 struct tcpcb * 560 tcp_newtcpcb(inp) 561 struct inpcb *inp; 562 { 563 struct inp_tp *it; 564 struct tcpcb *tp; 565 #ifdef INET6 566 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 567 #endif /* INET6 */ 568 569 it = (struct inp_tp *)inp; 570 tp = &it->tcb; 571 bzero((char *) tp, sizeof(struct tcpcb)); 572 LIST_INIT(&tp->t_segq); 573 tp->t_maxseg = tp->t_maxopd = 574 #ifdef INET6 575 isipv6 ? tcp_v6mssdflt : 576 #endif /* INET6 */ 577 tcp_mssdflt; 578 579 /* Set up our timeouts. */ 580 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt); 581 callout_init(tp->tt_persist = &it->inp_tp_persist); 582 callout_init(tp->tt_keep = &it->inp_tp_keep); 583 callout_init(tp->tt_2msl = &it->inp_tp_2msl); 584 callout_init(tp->tt_delack = &it->inp_tp_delack); 585 586 if (tcp_do_rfc1323) 587 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 588 if (tcp_do_rfc1644) 589 tp->t_flags |= TF_REQ_CC; 590 tp->t_inpcb = inp; /* XXX */ 591 /* 592 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 593 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 594 * reasonable initial retransmit time. 595 */ 596 tp->t_srtt = TCPTV_SRTTBASE; 597 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 598 tp->t_rttmin = tcp_rexmit_min; 599 tp->t_rxtcur = TCPTV_RTOBASE; 600 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 601 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 602 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 603 tp->t_rcvtime = ticks; 604 tp->t_bw_rtttime = ticks; 605 /* 606 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 607 * because the socket may be bound to an IPv6 wildcard address, 608 * which may match an IPv4-mapped IPv6 address. 609 */ 610 inp->inp_ip_ttl = ip_defttl; 611 inp->inp_ppcb = (caddr_t)tp; 612 return (tp); /* XXX */ 613 } 614 615 /* 616 * Drop a TCP connection, reporting 617 * the specified error. If connection is synchronized, 618 * then send a RST to peer. 619 */ 620 struct tcpcb * 621 tcp_drop(tp, errno) 622 struct tcpcb *tp; 623 int errno; 624 { 625 struct socket *so = tp->t_inpcb->inp_socket; 626 627 if (TCPS_HAVERCVDSYN(tp->t_state)) { 628 tp->t_state = TCPS_CLOSED; 629 (void) tcp_output(tp); 630 tcpstat.tcps_drops++; 631 } else 632 tcpstat.tcps_conndrops++; 633 if (errno == ETIMEDOUT && tp->t_softerror) 634 errno = tp->t_softerror; 635 so->so_error = errno; 636 return (tcp_close(tp)); 637 } 638 639 /* 640 * Close a TCP control block: 641 * discard all space held by the tcp 642 * discard internet protocol block 643 * wake up any sleepers 644 */ 645 struct tcpcb * 646 tcp_close(tp) 647 struct tcpcb *tp; 648 { 649 struct tseg_qent *q; 650 struct inpcb *inp = tp->t_inpcb; 651 struct socket *so = inp->inp_socket; 652 #ifdef INET6 653 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 654 #endif /* INET6 */ 655 struct rtentry *rt; 656 int dosavessthresh; 657 658 /* 659 * Make sure that all of our timers are stopped before we 660 * delete the PCB. 661 */ 662 callout_stop(tp->tt_rexmt); 663 callout_stop(tp->tt_persist); 664 callout_stop(tp->tt_keep); 665 callout_stop(tp->tt_2msl); 666 callout_stop(tp->tt_delack); 667 668 /* 669 * If we got enough samples through the srtt filter, 670 * save the rtt and rttvar in the routing entry. 671 * 'Enough' is arbitrarily defined as the 16 samples. 672 * 16 samples is enough for the srtt filter to converge 673 * to within 5% of the correct value; fewer samples and 674 * we could save a very bogus rtt. 675 * 676 * Don't update the default route's characteristics and don't 677 * update anything that the user "locked". 678 */ 679 if (tp->t_rttupdated >= 16) { 680 u_long i = 0; 681 #ifdef INET6 682 if (isipv6) { 683 struct sockaddr_in6 *sin6; 684 685 if ((rt = inp->in6p_route.ro_rt) == NULL) 686 goto no_valid_rt; 687 sin6 = (struct sockaddr_in6 *)rt_key(rt); 688 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 689 goto no_valid_rt; 690 } 691 else 692 #endif /* INET6 */ 693 if ((rt = inp->inp_route.ro_rt) == NULL || 694 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr 695 == INADDR_ANY) 696 goto no_valid_rt; 697 698 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 699 i = tp->t_srtt * 700 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 701 if (rt->rt_rmx.rmx_rtt && i) 702 /* 703 * filter this update to half the old & half 704 * the new values, converting scale. 705 * See route.h and tcp_var.h for a 706 * description of the scaling constants. 707 */ 708 rt->rt_rmx.rmx_rtt = 709 (rt->rt_rmx.rmx_rtt + i) / 2; 710 else 711 rt->rt_rmx.rmx_rtt = i; 712 tcpstat.tcps_cachedrtt++; 713 } 714 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 715 i = tp->t_rttvar * 716 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 717 if (rt->rt_rmx.rmx_rttvar && i) 718 rt->rt_rmx.rmx_rttvar = 719 (rt->rt_rmx.rmx_rttvar + i) / 2; 720 else 721 rt->rt_rmx.rmx_rttvar = i; 722 tcpstat.tcps_cachedrttvar++; 723 } 724 /* 725 * The old comment here said: 726 * update the pipelimit (ssthresh) if it has been updated 727 * already or if a pipesize was specified & the threshhold 728 * got below half the pipesize. I.e., wait for bad news 729 * before we start updating, then update on both good 730 * and bad news. 731 * 732 * But we want to save the ssthresh even if no pipesize is 733 * specified explicitly in the route, because such 734 * connections still have an implicit pipesize specified 735 * by the global tcp_sendspace. In the absence of a reliable 736 * way to calculate the pipesize, it will have to do. 737 */ 738 i = tp->snd_ssthresh; 739 if (rt->rt_rmx.rmx_sendpipe != 0) 740 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2); 741 else 742 dosavessthresh = (i < so->so_snd.sb_hiwat / 2); 743 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 744 i != 0 && rt->rt_rmx.rmx_ssthresh != 0) 745 || dosavessthresh) { 746 /* 747 * convert the limit from user data bytes to 748 * packets then to packet data bytes. 749 */ 750 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 751 if (i < 2) 752 i = 2; 753 i *= (u_long)(tp->t_maxseg + 754 #ifdef INET6 755 (isipv6 ? sizeof (struct ip6_hdr) + 756 sizeof (struct tcphdr) : 757 #endif 758 sizeof (struct tcpiphdr) 759 #ifdef INET6 760 ) 761 #endif 762 ); 763 if (rt->rt_rmx.rmx_ssthresh) 764 rt->rt_rmx.rmx_ssthresh = 765 (rt->rt_rmx.rmx_ssthresh + i) / 2; 766 else 767 rt->rt_rmx.rmx_ssthresh = i; 768 tcpstat.tcps_cachedssthresh++; 769 } 770 } 771 no_valid_rt: 772 /* free the reassembly queue, if any */ 773 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 774 LIST_REMOVE(q, tqe_q); 775 m_freem(q->tqe_m); 776 FREE(q, M_TSEGQ); 777 tcp_reass_qsize--; 778 } 779 inp->inp_ppcb = NULL; 780 soisdisconnected(so); 781 #ifdef INET6 782 if (INP_CHECK_SOCKAF(so, AF_INET6)) 783 in6_pcbdetach(inp); 784 else 785 #endif /* INET6 */ 786 in_pcbdetach(inp); 787 tcpstat.tcps_closed++; 788 return ((struct tcpcb *)0); 789 } 790 791 static __inline void 792 tcp_drain_oncpu(struct inpcbhead *head) 793 { 794 struct inpcb *inpb; 795 struct tcpcb *tcpb; 796 struct tseg_qent *te; 797 798 LIST_FOREACH(inpb, head, inp_list) { 799 if ((tcpb = intotcpcb(inpb))) { 800 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) { 801 LIST_REMOVE(te, tqe_q); 802 m_freem(te->tqe_m); 803 FREE(te, M_TSEGQ); 804 tcp_reass_qsize--; 805 } 806 } 807 } 808 } 809 810 #ifdef SMP 811 struct netmsg_tcp_drain { 812 struct lwkt_msg nm_lmsg; 813 netisr_fn_t nm_handler; 814 struct inpcbhead *nm_head; 815 }; 816 817 static int /* really should be void XXX JH */ 818 tcp_drain_handler(struct netmsg *msg0) 819 { 820 struct netmsg_tcp_drain *nm = (struct netmsg_tcp_drain *)msg0; 821 822 tcp_drain_oncpu(nm->nm_head); 823 824 return (0); /* dummy return value */ 825 } 826 #endif 827 828 void 829 tcp_drain() 830 { 831 #ifdef SMP 832 int cpu; 833 #endif 834 835 if (!do_tcpdrain) 836 return; 837 838 /* 839 * Walk the tcpbs, if existing, and flush the reassembly queue, 840 * if there is one... 841 * XXX: The "Net/3" implementation doesn't imply that the TCP 842 * reassembly queue should be flushed, but in a situation 843 * where we're really low on mbufs, this is potentially 844 * usefull. 845 */ 846 #ifdef SMP 847 for (cpu = 0; cpu < ncpus2; cpu++) { 848 struct netmsg_tcp_drain *msg; 849 850 if (cpu == mycpu->gd_cpuid) { 851 tcp_drain_oncpu(&tcbinfo[cpu].listhead); 852 } else { 853 msg = malloc(sizeof(struct netmsg_tcp_drain), 854 M_LWKTMSG, M_NOWAIT); 855 if (!msg) 856 continue; 857 lwkt_initmsg_rp(&msg->nm_lmsg, &netisr_afree_rport, 858 CMD_NETMSG_ONCPU); 859 msg->nm_handler = tcp_drain_handler; 860 msg->nm_head = &tcbinfo[cpu].listhead; 861 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_lmsg); 862 } 863 } 864 #else 865 tcp_drain_oncpu(&tcbinfo[0].listhead); 866 #endif 867 } 868 869 /* 870 * Notify a tcp user of an asynchronous error; 871 * store error as soft error, but wake up user 872 * (for now, won't do anything until can select for soft error). 873 * 874 * Do not wake up user since there currently is no mechanism for 875 * reporting soft errors (yet - a kqueue filter may be added). 876 */ 877 static void 878 tcp_notify(inp, error) 879 struct inpcb *inp; 880 int error; 881 { 882 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 883 884 /* 885 * Ignore some errors if we are hooked up. 886 * If connection hasn't completed, has retransmitted several times, 887 * and receives a second error, give up now. This is better 888 * than waiting a long time to establish a connection that 889 * can never complete. 890 */ 891 if (tp->t_state == TCPS_ESTABLISHED && 892 (error == EHOSTUNREACH || error == ENETUNREACH || 893 error == EHOSTDOWN)) { 894 return; 895 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 896 tp->t_softerror) 897 tcp_drop(tp, error); 898 else 899 tp->t_softerror = error; 900 #if 0 901 wakeup((caddr_t) &so->so_timeo); 902 sorwakeup(so); 903 sowwakeup(so); 904 #endif 905 } 906 907 static int 908 tcp_pcblist(SYSCTL_HANDLER_ARGS) 909 { 910 int error, i, n, s; 911 struct inpcb *inp, **inp_list; 912 inp_gen_t gencnt; 913 struct xinpgen xig; 914 915 /* 916 * The process of preparing the TCB list is too time-consuming and 917 * resource-intensive to repeat twice on every request. 918 */ 919 if (req->oldptr == 0) { 920 n = tcbinfo[mycpu->gd_cpuid].ipi_count; 921 req->oldidx = 2 * (sizeof xig) 922 + (n + n/8) * sizeof(struct xtcpcb); 923 return 0; 924 } 925 926 if (req->newptr != 0) 927 return EPERM; 928 929 /* 930 * OK, now we're committed to doing something. 931 */ 932 s = splnet(); 933 gencnt = tcbinfo[mycpu->gd_cpuid].ipi_gencnt; 934 n = tcbinfo[mycpu->gd_cpuid].ipi_count; 935 splx(s); 936 937 xig.xig_len = sizeof xig; 938 xig.xig_count = n; 939 xig.xig_gen = gencnt; 940 xig.xig_sogen = so_gencnt; 941 error = SYSCTL_OUT(req, &xig, sizeof xig); 942 if (error) 943 return error; 944 945 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 946 if (inp_list == 0) 947 return ENOMEM; 948 949 s = splnet(); 950 for (inp = LIST_FIRST(&tcbinfo[mycpu->gd_cpuid].listhead), i = 0; 951 inp && i < n; inp = LIST_NEXT(inp, inp_list)) { 952 if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->td, inp)) 953 inp_list[i++] = inp; 954 } 955 splx(s); 956 n = i; 957 958 error = 0; 959 for (i = 0; i < n; i++) { 960 inp = inp_list[i]; 961 if (inp->inp_gencnt <= gencnt) { 962 struct xtcpcb xt; 963 caddr_t inp_ppcb; 964 xt.xt_len = sizeof xt; 965 /* XXX should avoid extra copy */ 966 bcopy(inp, &xt.xt_inp, sizeof *inp); 967 inp_ppcb = inp->inp_ppcb; 968 if (inp_ppcb != NULL) 969 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 970 else 971 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 972 if (inp->inp_socket) 973 sotoxsocket(inp->inp_socket, &xt.xt_socket); 974 error = SYSCTL_OUT(req, &xt, sizeof xt); 975 } 976 } 977 if (!error) { 978 /* 979 * Give the user an updated idea of our state. 980 * If the generation differs from what we told 981 * her before, she knows that something happened 982 * while we were processing this request, and it 983 * might be necessary to retry. 984 */ 985 s = splnet(); 986 xig.xig_gen = tcbinfo[mycpu->gd_cpuid].ipi_gencnt; 987 xig.xig_sogen = so_gencnt; 988 xig.xig_count = tcbinfo[mycpu->gd_cpuid].ipi_count; 989 splx(s); 990 error = SYSCTL_OUT(req, &xig, sizeof xig); 991 } 992 free(inp_list, M_TEMP); 993 return error; 994 } 995 996 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 997 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 998 999 static int 1000 tcp_getcred(SYSCTL_HANDLER_ARGS) 1001 { 1002 struct sockaddr_in addrs[2]; 1003 struct inpcb *inp; 1004 int cpu; 1005 int error, s; 1006 1007 error = suser(req->td); 1008 if (error) 1009 return (error); 1010 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1011 if (error) 1012 return (error); 1013 s = splnet(); 1014 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1015 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1016 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1017 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1018 if (inp == NULL || inp->inp_socket == NULL) { 1019 error = ENOENT; 1020 goto out; 1021 } 1022 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1023 out: 1024 splx(s); 1025 return (error); 1026 } 1027 1028 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 1029 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1030 1031 #ifdef INET6 1032 static int 1033 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1034 { 1035 struct sockaddr_in6 addrs[2]; 1036 struct inpcb *inp; 1037 int error, s, mapped = 0; 1038 1039 error = suser(req->td); 1040 if (error) 1041 return (error); 1042 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1043 if (error) 1044 return (error); 1045 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1046 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1047 mapped = 1; 1048 else 1049 return (EINVAL); 1050 } 1051 s = splnet(); 1052 if (mapped == 1) { 1053 inp = in_pcblookup_hash(&tcbinfo[0], 1054 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1055 addrs[1].sin6_port, 1056 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1057 addrs[0].sin6_port, 1058 0, NULL); 1059 } else { 1060 inp = in6_pcblookup_hash(&tcbinfo[0], 1061 &addrs[1].sin6_addr, addrs[1].sin6_port, 1062 &addrs[0].sin6_addr, addrs[0].sin6_port, 1063 0, NULL); 1064 } 1065 if (inp == NULL || inp->inp_socket == NULL) { 1066 error = ENOENT; 1067 goto out; 1068 } 1069 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, 1070 sizeof(struct ucred)); 1071 out: 1072 splx(s); 1073 return (error); 1074 } 1075 1076 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 1077 0, 0, 1078 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1079 #endif 1080 1081 1082 void 1083 tcp_ctlinput(cmd, sa, vip) 1084 int cmd; 1085 struct sockaddr *sa; 1086 void *vip; 1087 { 1088 struct ip *ip = vip; 1089 struct tcphdr *th; 1090 struct in_addr faddr; 1091 struct inpcb *inp; 1092 struct tcpcb *tp; 1093 void (*notify) (struct inpcb *, int) = tcp_notify; 1094 tcp_seq icmp_seq; 1095 int cpu; 1096 int s; 1097 1098 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1099 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1100 return; 1101 1102 if (cmd == PRC_QUENCH) 1103 notify = tcp_quench; 1104 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1105 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1106 notify = tcp_drop_syn_sent; 1107 else if (cmd == PRC_MSGSIZE) 1108 notify = tcp_mtudisc; 1109 else if (PRC_IS_REDIRECT(cmd)) { 1110 ip = 0; 1111 notify = in_rtchange; 1112 } else if (cmd == PRC_HOSTDEAD) 1113 ip = 0; 1114 else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0) 1115 return; 1116 if (ip) { 1117 s = splnet(); 1118 th = (struct tcphdr *)((caddr_t)ip 1119 + (IP_VHL_HL(ip->ip_vhl) << 2)); 1120 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1121 ip->ip_src.s_addr, th->th_sport); 1122 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1123 ip->ip_src, th->th_sport, 0, NULL); 1124 if (inp != NULL && inp->inp_socket != NULL) { 1125 icmp_seq = htonl(th->th_seq); 1126 tp = intotcpcb(inp); 1127 if (SEQ_GEQ(icmp_seq, tp->snd_una) && 1128 SEQ_LT(icmp_seq, tp->snd_max)) 1129 (*notify)(inp, inetctlerrmap[cmd]); 1130 } else { 1131 struct in_conninfo inc; 1132 1133 inc.inc_fport = th->th_dport; 1134 inc.inc_lport = th->th_sport; 1135 inc.inc_faddr = faddr; 1136 inc.inc_laddr = ip->ip_src; 1137 #ifdef INET6 1138 inc.inc_isipv6 = 0; 1139 #endif 1140 syncache_unreach(&inc, th); 1141 } 1142 splx(s); 1143 } else { 1144 for (cpu = 0; cpu < ncpus2; cpu++) 1145 in_pcbnotifyall(&tcbinfo[cpu].listhead, faddr, 1146 inetctlerrmap[cmd], notify); 1147 } 1148 } 1149 1150 #ifdef INET6 1151 void 1152 tcp6_ctlinput(cmd, sa, d) 1153 int cmd; 1154 struct sockaddr *sa; 1155 void *d; 1156 { 1157 struct tcphdr th; 1158 void (*notify) (struct inpcb *, int) = tcp_notify; 1159 struct ip6_hdr *ip6; 1160 struct mbuf *m; 1161 struct ip6ctlparam *ip6cp = NULL; 1162 const struct sockaddr_in6 *sa6_src = NULL; 1163 int off; 1164 struct tcp_portonly { 1165 u_int16_t th_sport; 1166 u_int16_t th_dport; 1167 } *thp; 1168 1169 if (sa->sa_family != AF_INET6 || 1170 sa->sa_len != sizeof(struct sockaddr_in6)) 1171 return; 1172 1173 if (cmd == PRC_QUENCH) 1174 notify = tcp_quench; 1175 else if (cmd == PRC_MSGSIZE) 1176 notify = tcp_mtudisc; 1177 else if (!PRC_IS_REDIRECT(cmd) && 1178 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1179 return; 1180 1181 /* if the parameter is from icmp6, decode it. */ 1182 if (d != NULL) { 1183 ip6cp = (struct ip6ctlparam *)d; 1184 m = ip6cp->ip6c_m; 1185 ip6 = ip6cp->ip6c_ip6; 1186 off = ip6cp->ip6c_off; 1187 sa6_src = ip6cp->ip6c_src; 1188 } else { 1189 m = NULL; 1190 ip6 = NULL; 1191 off = 0; /* fool gcc */ 1192 sa6_src = &sa6_any; 1193 } 1194 1195 if (ip6) { 1196 struct in_conninfo inc; 1197 /* 1198 * XXX: We assume that when IPV6 is non NULL, 1199 * M and OFF are valid. 1200 */ 1201 1202 /* check if we can safely examine src and dst ports */ 1203 if (m->m_pkthdr.len < off + sizeof(*thp)) 1204 return; 1205 1206 bzero(&th, sizeof(th)); 1207 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1208 1209 in6_pcbnotify(&tcbinfo[0].listhead, sa, th.th_dport, 1210 (struct sockaddr *)ip6cp->ip6c_src, 1211 th.th_sport, cmd, notify); 1212 1213 inc.inc_fport = th.th_dport; 1214 inc.inc_lport = th.th_sport; 1215 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1216 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1217 inc.inc_isipv6 = 1; 1218 syncache_unreach(&inc, &th); 1219 } else 1220 in6_pcbnotify(&tcbinfo[0].listhead, sa, 0, 1221 (const struct sockaddr *)sa6_src, 0, cmd, notify); 1222 } 1223 #endif /* INET6 */ 1224 1225 1226 /* 1227 * Following is where TCP initial sequence number generation occurs. 1228 * 1229 * There are two places where we must use initial sequence numbers: 1230 * 1. In SYN-ACK packets. 1231 * 2. In SYN packets. 1232 * 1233 * All ISNs for SYN-ACK packets are generated by the syncache. See 1234 * tcp_syncache.c for details. 1235 * 1236 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1237 * depends on this property. In addition, these ISNs should be 1238 * unguessable so as to prevent connection hijacking. To satisfy 1239 * the requirements of this situation, the algorithm outlined in 1240 * RFC 1948 is used to generate sequence numbers. 1241 * 1242 * Implementation details: 1243 * 1244 * Time is based off the system timer, and is corrected so that it 1245 * increases by one megabyte per second. This allows for proper 1246 * recycling on high speed LANs while still leaving over an hour 1247 * before rollover. 1248 * 1249 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1250 * between seeding of isn_secret. This is normally set to zero, 1251 * as reseeding should not be necessary. 1252 * 1253 */ 1254 1255 #define ISN_BYTES_PER_SECOND 1048576 1256 1257 u_char isn_secret[32]; 1258 int isn_last_reseed; 1259 MD5_CTX isn_ctx; 1260 1261 tcp_seq 1262 tcp_new_isn(tp) 1263 struct tcpcb *tp; 1264 { 1265 u_int32_t md5_buffer[4]; 1266 tcp_seq new_isn; 1267 1268 /* Seed if this is the first use, reseed if requested. */ 1269 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1270 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1271 < (u_int)ticks))) { 1272 read_random_unlimited(&isn_secret, sizeof(isn_secret)); 1273 isn_last_reseed = ticks; 1274 } 1275 1276 /* Compute the md5 hash and return the ISN. */ 1277 MD5Init(&isn_ctx); 1278 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1279 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1280 #ifdef INET6 1281 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1282 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1283 sizeof(struct in6_addr)); 1284 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1285 sizeof(struct in6_addr)); 1286 } else 1287 #endif 1288 { 1289 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1290 sizeof(struct in_addr)); 1291 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1292 sizeof(struct in_addr)); 1293 } 1294 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1295 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1296 new_isn = (tcp_seq) md5_buffer[0]; 1297 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1298 return new_isn; 1299 } 1300 1301 /* 1302 * When a source quench is received, close congestion window 1303 * to one segment. We will gradually open it again as we proceed. 1304 */ 1305 void 1306 tcp_quench(inp, errno) 1307 struct inpcb *inp; 1308 int errno; 1309 { 1310 struct tcpcb *tp = intotcpcb(inp); 1311 1312 if (tp) 1313 tp->snd_cwnd = tp->t_maxseg; 1314 } 1315 1316 /* 1317 * When a specific ICMP unreachable message is received and the 1318 * connection state is SYN-SENT, drop the connection. This behavior 1319 * is controlled by the icmp_may_rst sysctl. 1320 */ 1321 void 1322 tcp_drop_syn_sent(inp, errno) 1323 struct inpcb *inp; 1324 int errno; 1325 { 1326 struct tcpcb *tp = intotcpcb(inp); 1327 1328 if (tp && tp->t_state == TCPS_SYN_SENT) 1329 tcp_drop(tp, errno); 1330 } 1331 1332 /* 1333 * When `need fragmentation' ICMP is received, update our idea of the MSS 1334 * based on the new value in the route. Also nudge TCP to send something, 1335 * since we know the packet we just sent was dropped. 1336 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1337 */ 1338 void 1339 tcp_mtudisc(inp, errno) 1340 struct inpcb *inp; 1341 int errno; 1342 { 1343 struct tcpcb *tp = intotcpcb(inp); 1344 struct rtentry *rt; 1345 struct rmxp_tao *taop; 1346 struct socket *so = inp->inp_socket; 1347 int offered; 1348 int mss; 1349 #ifdef INET6 1350 int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1351 #endif /* INET6 */ 1352 1353 if (tp) { 1354 #ifdef INET6 1355 if (isipv6) 1356 rt = tcp_rtlookup6(&inp->inp_inc); 1357 else 1358 #endif /* INET6 */ 1359 rt = tcp_rtlookup(&inp->inp_inc); 1360 if (!rt || !rt->rt_rmx.rmx_mtu) { 1361 tp->t_maxopd = tp->t_maxseg = 1362 #ifdef INET6 1363 isipv6 ? tcp_v6mssdflt : 1364 #endif /* INET6 */ 1365 tcp_mssdflt; 1366 return; 1367 } 1368 taop = rmx_taop(rt->rt_rmx); 1369 offered = taop->tao_mssopt; 1370 mss = rt->rt_rmx.rmx_mtu - 1371 #ifdef INET6 1372 (isipv6 ? 1373 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1374 #endif /* INET6 */ 1375 sizeof(struct tcpiphdr) 1376 #ifdef INET6 1377 ) 1378 #endif /* INET6 */ 1379 ; 1380 1381 if (offered) 1382 mss = min(mss, offered); 1383 /* 1384 * XXX - The above conditional probably violates the TCP 1385 * spec. The problem is that, since we don't know the 1386 * other end's MSS, we are supposed to use a conservative 1387 * default. But, if we do that, then MTU discovery will 1388 * never actually take place, because the conservative 1389 * default is much less than the MTUs typically seen 1390 * on the Internet today. For the moment, we'll sweep 1391 * this under the carpet. 1392 * 1393 * The conservative default might not actually be a problem 1394 * if the only case this occurs is when sending an initial 1395 * SYN with options and data to a host we've never talked 1396 * to before. Then, they will reply with an MSS value which 1397 * will get recorded and the new parameters should get 1398 * recomputed. For Further Study. 1399 */ 1400 if (tp->t_maxopd <= mss) 1401 return; 1402 tp->t_maxopd = mss; 1403 1404 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1405 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1406 mss -= TCPOLEN_TSTAMP_APPA; 1407 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC && 1408 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC) 1409 mss -= TCPOLEN_CC_APPA; 1410 #if (MCLBYTES & (MCLBYTES - 1)) == 0 1411 if (mss > MCLBYTES) 1412 mss &= ~(MCLBYTES-1); 1413 #else 1414 if (mss > MCLBYTES) 1415 mss = mss / MCLBYTES * MCLBYTES; 1416 #endif 1417 if (so->so_snd.sb_hiwat < mss) 1418 mss = so->so_snd.sb_hiwat; 1419 1420 tp->t_maxseg = mss; 1421 1422 tcpstat.tcps_mturesent++; 1423 tp->t_rtttime = 0; 1424 tp->snd_nxt = tp->snd_una; 1425 tcp_output(tp); 1426 } 1427 } 1428 1429 /* 1430 * Look-up the routing entry to the peer of this inpcb. If no route 1431 * is found and it cannot be allocated the return NULL. This routine 1432 * is called by TCP routines that access the rmx structure and by tcp_mss 1433 * to get the interface MTU. 1434 */ 1435 struct rtentry * 1436 tcp_rtlookup(inc) 1437 struct in_conninfo *inc; 1438 { 1439 struct route *ro; 1440 struct rtentry *rt; 1441 1442 ro = &inc->inc_route; 1443 rt = ro->ro_rt; 1444 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1445 /* No route yet, so try to acquire one */ 1446 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1447 ro->ro_dst.sa_family = AF_INET; 1448 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1449 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1450 inc->inc_faddr; 1451 rtalloc(ro); 1452 rt = ro->ro_rt; 1453 } 1454 } 1455 return rt; 1456 } 1457 1458 #ifdef INET6 1459 struct rtentry * 1460 tcp_rtlookup6(inc) 1461 struct in_conninfo *inc; 1462 { 1463 struct route_in6 *ro6; 1464 struct rtentry *rt; 1465 1466 ro6 = &inc->inc6_route; 1467 rt = ro6->ro_rt; 1468 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 1469 /* No route yet, so try to acquire one */ 1470 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1471 ro6->ro_dst.sin6_family = AF_INET6; 1472 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1473 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1474 rtalloc((struct route *)ro6); 1475 rt = ro6->ro_rt; 1476 } 1477 } 1478 return rt; 1479 } 1480 #endif /* INET6 */ 1481 1482 #ifdef IPSEC 1483 /* compute ESP/AH header size for TCP, including outer IP header. */ 1484 size_t 1485 ipsec_hdrsiz_tcp(tp) 1486 struct tcpcb *tp; 1487 { 1488 struct inpcb *inp; 1489 struct mbuf *m; 1490 size_t hdrsiz; 1491 struct ip *ip; 1492 #ifdef INET6 1493 struct ip6_hdr *ip6; 1494 #endif /* INET6 */ 1495 struct tcphdr *th; 1496 1497 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1498 return 0; 1499 MGETHDR(m, M_DONTWAIT, MT_DATA); 1500 if (!m) 1501 return 0; 1502 1503 #ifdef INET6 1504 if ((inp->inp_vflag & INP_IPV6) != 0) { 1505 ip6 = mtod(m, struct ip6_hdr *); 1506 th = (struct tcphdr *)(ip6 + 1); 1507 m->m_pkthdr.len = m->m_len = 1508 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1509 tcp_fillheaders(tp, ip6, th); 1510 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1511 } else 1512 #endif /* INET6 */ 1513 { 1514 ip = mtod(m, struct ip *); 1515 th = (struct tcphdr *)(ip + 1); 1516 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1517 tcp_fillheaders(tp, ip, th); 1518 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1519 } 1520 1521 m_free(m); 1522 return hdrsiz; 1523 } 1524 #endif /*IPSEC*/ 1525 1526 /* 1527 * Return a pointer to the cached information about the remote host. 1528 * The cached information is stored in the protocol specific part of 1529 * the route metrics. 1530 */ 1531 struct rmxp_tao * 1532 tcp_gettaocache(inc) 1533 struct in_conninfo *inc; 1534 { 1535 struct rtentry *rt; 1536 1537 #ifdef INET6 1538 if (inc->inc_isipv6) 1539 rt = tcp_rtlookup6(inc); 1540 else 1541 #endif /* INET6 */ 1542 rt = tcp_rtlookup(inc); 1543 1544 /* Make sure this is a host route and is up. */ 1545 if (rt == NULL || 1546 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)) 1547 return NULL; 1548 1549 return rmx_taop(rt->rt_rmx); 1550 } 1551 1552 /* 1553 * Clear all the TAO cache entries, called from tcp_init. 1554 * 1555 * XXX 1556 * This routine is just an empty one, because we assume that the routing 1557 * routing tables are initialized at the same time when TCP, so there is 1558 * nothing in the cache left over. 1559 */ 1560 static void 1561 tcp_cleartaocache() 1562 { 1563 } 1564 1565 /* 1566 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1567 * 1568 * This code attempts to calculate the bandwidth-delay product as a 1569 * means of determining the optimal window size to maximize bandwidth, 1570 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1571 * routers. This code also does a fairly good job keeping RTTs in check 1572 * across slow links like modems. We implement an algorithm which is very 1573 * similar (but not meant to be) TCP/Vegas. The code operates on the 1574 * transmitter side of a TCP connection and so only effects the transmit 1575 * side of the connection. 1576 * 1577 * BACKGROUND: TCP makes no provision for the management of buffer space 1578 * at the end points or at the intermediate routers and switches. A TCP 1579 * stream, whether using NewReno or not, will eventually buffer as 1580 * many packets as it is able and the only reason this typically works is 1581 * due to the fairly small default buffers made available for a connection 1582 * (typicaly 16K or 32K). As machines use larger windows and/or window 1583 * scaling it is now fairly easy for even a single TCP connection to blow-out 1584 * all available buffer space not only on the local interface, but on 1585 * intermediate routers and switches as well. NewReno makes a misguided 1586 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1587 * then backing off, then steadily increasing the window again until another 1588 * failure occurs, ad-infinitum. This results in terrible oscillation that 1589 * is only made worse as network loads increase and the idea of intentionally 1590 * blowing out network buffers is, frankly, a terrible way to manage network 1591 * resources. 1592 * 1593 * It is far better to limit the transmit window prior to the failure 1594 * condition being achieved. There are two general ways to do this: First 1595 * you can 'scan' through different transmit window sizes and locate the 1596 * point where the RTT stops increasing, indicating that you have filled the 1597 * pipe, then scan backwards until you note that RTT stops decreasing, then 1598 * repeat ad-infinitum. This method works in principle but has severe 1599 * implementation issues due to RTT variances, timer granularity, and 1600 * instability in the algorithm which can lead to many false positives and 1601 * create oscillations as well as interact badly with other TCP streams 1602 * implementing the same algorithm. 1603 * 1604 * The second method is to limit the window to the bandwidth delay product 1605 * of the link. This is the method we implement. RTT variances and our 1606 * own manipulation of the congestion window, bwnd, can potentially 1607 * destabilize the algorithm. For this reason we have to stabilize the 1608 * elements used to calculate the window. We do this by using the minimum 1609 * observed RTT, the long term average of the observed bandwidth, and 1610 * by adding two segments worth of slop. It isn't perfect but it is able 1611 * to react to changing conditions and gives us a very stable basis on 1612 * which to extend the algorithm. 1613 */ 1614 void 1615 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1616 { 1617 u_long bw; 1618 u_long bwnd; 1619 int save_ticks; 1620 1621 /* 1622 * If inflight_enable is disabled in the middle of a tcp connection, 1623 * make sure snd_bwnd is effectively disabled. 1624 */ 1625 if (tcp_inflight_enable == 0) { 1626 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1627 tp->snd_bandwidth = 0; 1628 return; 1629 } 1630 1631 /* 1632 * Figure out the bandwidth. Due to the tick granularity this 1633 * is a very rough number and it MUST be averaged over a fairly 1634 * long period of time. XXX we need to take into account a link 1635 * that is not using all available bandwidth, but for now our 1636 * slop will ramp us up if this case occurs and the bandwidth later 1637 * increases. 1638 * 1639 * Note: if ticks rollover 'bw' may wind up negative. We must 1640 * effectively reset t_bw_rtttime for this case. 1641 */ 1642 save_ticks = ticks; 1643 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 1644 return; 1645 1646 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 1647 (save_ticks - tp->t_bw_rtttime); 1648 tp->t_bw_rtttime = save_ticks; 1649 tp->t_bw_rtseq = ack_seq; 1650 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 1651 return; 1652 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1653 1654 tp->snd_bandwidth = bw; 1655 1656 /* 1657 * Calculate the semi-static bandwidth delay product, plus two maximal 1658 * segments. The additional slop puts us squarely in the sweet 1659 * spot and also handles the bandwidth run-up case. Without the 1660 * slop we could be locking ourselves into a lower bandwidth. 1661 * 1662 * Situations Handled: 1663 * (1) Prevents over-queueing of packets on LANs, especially on 1664 * high speed LANs, allowing larger TCP buffers to be 1665 * specified, and also does a good job preventing 1666 * over-queueing of packets over choke points like modems 1667 * (at least for the transmit side). 1668 * 1669 * (2) Is able to handle changing network loads (bandwidth 1670 * drops so bwnd drops, bandwidth increases so bwnd 1671 * increases). 1672 * 1673 * (3) Theoretically should stabilize in the face of multiple 1674 * connections implementing the same algorithm (this may need 1675 * a little work). 1676 * 1677 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1678 * be adjusted with a sysctl but typically only needs to be on 1679 * very slow connections. A value no smaller then 5 should 1680 * be used, but only reduce this default if you have no other 1681 * choice. 1682 */ 1683 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1684 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + tcp_inflight_stab * (int)tp->t_maxseg / 10; 1685 #undef USERTT 1686 1687 if (tcp_inflight_debug > 0) { 1688 static int ltime; 1689 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1690 ltime = ticks; 1691 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1692 tp, 1693 bw, 1694 tp->t_rttbest, 1695 tp->t_srtt, 1696 bwnd 1697 ); 1698 } 1699 } 1700 if ((long)bwnd < tcp_inflight_min) 1701 bwnd = tcp_inflight_min; 1702 if (bwnd > tcp_inflight_max) 1703 bwnd = tcp_inflight_max; 1704 if ((long)bwnd < tp->t_maxseg * 2) 1705 bwnd = tp->t_maxseg * 2; 1706 tp->snd_bwnd = bwnd; 1707 } 1708