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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 30 * $FreeBSD$ 31 */ 32 33 #include "opt_compat.h" 34 #include "opt_inet.h" 35 #include "opt_inet6.h" 36 #include "opt_ipsec.h" 37 #include "opt_mac.h" 38 #include "opt_tcpdebug.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/callout.h> 43 #include <sys/kernel.h> 44 #include <sys/sysctl.h> 45 #include <sys/malloc.h> 46 #include <sys/mbuf.h> 47 #ifdef INET6 48 #include <sys/domain.h> 49 #endif 50 #include <sys/priv.h> 51 #include <sys/proc.h> 52 #include <sys/socket.h> 53 #include <sys/socketvar.h> 54 #include <sys/protosw.h> 55 #include <sys/random.h> 56 57 #include <vm/uma.h> 58 59 #include <net/route.h> 60 #include <net/if.h> 61 62 #include <netinet/in.h> 63 #include <netinet/in_systm.h> 64 #include <netinet/ip.h> 65 #ifdef INET6 66 #include <netinet/ip6.h> 67 #endif 68 #include <netinet/in_pcb.h> 69 #ifdef INET6 70 #include <netinet6/in6_pcb.h> 71 #endif 72 #include <netinet/in_var.h> 73 #include <netinet/ip_var.h> 74 #ifdef INET6 75 #include <netinet6/ip6_var.h> 76 #include <netinet6/scope6_var.h> 77 #include <netinet6/nd6.h> 78 #endif 79 #include <netinet/ip_icmp.h> 80 #include <netinet/tcp.h> 81 #include <netinet/tcp_fsm.h> 82 #include <netinet/tcp_seq.h> 83 #include <netinet/tcp_timer.h> 84 #include <netinet/tcp_var.h> 85 #ifdef INET6 86 #include <netinet6/tcp6_var.h> 87 #endif 88 #include <netinet/tcpip.h> 89 #ifdef TCPDEBUG 90 #include <netinet/tcp_debug.h> 91 #endif 92 #include <netinet6/ip6protosw.h> 93 94 #ifdef IPSEC 95 #include <netinet6/ipsec.h> 96 #ifdef INET6 97 #include <netinet6/ipsec6.h> 98 #endif 99 #include <netkey/key.h> 100 #endif /*IPSEC*/ 101 102 #ifdef FAST_IPSEC 103 #include <netipsec/ipsec.h> 104 #include <netipsec/xform.h> 105 #ifdef INET6 106 #include <netipsec/ipsec6.h> 107 #endif 108 #include <netipsec/key.h> 109 #define IPSEC 110 #endif /*FAST_IPSEC*/ 111 112 #include <machine/in_cksum.h> 113 #include <sys/md5.h> 114 115 #include <security/mac/mac_framework.h> 116 117 int tcp_mssdflt = TCP_MSS; 118 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 119 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size"); 120 121 #ifdef INET6 122 int tcp_v6mssdflt = TCP6_MSS; 123 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 124 CTLFLAG_RW, &tcp_v6mssdflt , 0, 125 "Default TCP Maximum Segment Size for IPv6"); 126 #endif 127 128 /* 129 * Minimum MSS we accept and use. This prevents DoS attacks where 130 * we are forced to a ridiculous low MSS like 20 and send hundreds 131 * of packets instead of one. The effect scales with the available 132 * bandwidth and quickly saturates the CPU and network interface 133 * with packet generation and sending. Set to zero to disable MINMSS 134 * checking. This setting prevents us from sending too small packets. 135 */ 136 int tcp_minmss = TCP_MINMSS; 137 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 138 &tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 139 140 int tcp_do_rfc1323 = 1; 141 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 142 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions"); 143 144 static int tcp_tcbhashsize = 0; 145 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 146 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 147 148 static int do_tcpdrain = 1; 149 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, 150 &do_tcpdrain, 0, 151 "Enable tcp_drain routine for extra help when low on mbufs"); 152 153 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 154 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 155 156 static int icmp_may_rst = 1; 157 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, 158 &icmp_may_rst, 0, 159 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 160 161 static int tcp_isn_reseed_interval = 0; 162 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 163 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 164 165 /* 166 * TCP bandwidth limiting sysctls. Note that the default lower bound of 167 * 1024 exists only for debugging. A good production default would be 168 * something like 6100. 169 */ 170 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0, 171 "TCP inflight data limiting"); 172 173 static int tcp_inflight_enable = 1; 174 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, enable, CTLFLAG_RW, 175 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 176 177 static int tcp_inflight_debug = 0; 178 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW, 179 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 180 181 static int tcp_inflight_rttthresh; 182 SYSCTL_PROC(_net_inet_tcp_inflight, OID_AUTO, rttthresh, CTLTYPE_INT|CTLFLAG_RW, 183 &tcp_inflight_rttthresh, 0, sysctl_msec_to_ticks, "I", 184 "RTT threshold below which inflight will deactivate itself"); 185 186 static int tcp_inflight_min = 6144; 187 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, min, CTLFLAG_RW, 188 &tcp_inflight_min, 0, "Lower-bound for TCP inflight window"); 189 190 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 191 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, max, CTLFLAG_RW, 192 &tcp_inflight_max, 0, "Upper-bound for TCP inflight window"); 193 194 static int tcp_inflight_stab = 20; 195 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, stab, CTLFLAG_RW, 196 &tcp_inflight_stab, 0, "Inflight Algorithm Stabilization 20 = 2 packets"); 197 198 uma_zone_t sack_hole_zone; 199 200 static struct inpcb *tcp_notify(struct inpcb *, int); 201 static void tcp_isn_tick(void *); 202 203 /* 204 * Target size of TCP PCB hash tables. Must be a power of two. 205 * 206 * Note that this can be overridden by the kernel environment 207 * variable net.inet.tcp.tcbhashsize 208 */ 209 #ifndef TCBHASHSIZE 210 #define TCBHASHSIZE 512 211 #endif 212 213 /* 214 * XXX 215 * Callouts should be moved into struct tcp directly. They are currently 216 * separate because the tcpcb structure is exported to userland for sysctl 217 * parsing purposes, which do not know about callouts. 218 */ 219 struct tcpcb_mem { 220 struct tcpcb tcb; 221 struct tcp_timer tt; 222 }; 223 224 static uma_zone_t tcpcb_zone; 225 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers"); 226 struct callout isn_callout; 227 static struct mtx isn_mtx; 228 229 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 230 #define ISN_LOCK() mtx_lock(&isn_mtx) 231 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 232 233 /* 234 * TCP initialization. 235 */ 236 static void 237 tcp_zone_change(void *tag) 238 { 239 240 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 241 uma_zone_set_max(tcpcb_zone, maxsockets); 242 tcp_tw_zone_change(); 243 } 244 245 static int 246 tcp_inpcb_init(void *mem, int size, int flags) 247 { 248 struct inpcb *inp = mem; 249 250 INP_LOCK_INIT(inp, "inp", "tcpinp"); 251 return (0); 252 } 253 254 void 255 tcp_init(void) 256 { 257 258 int hashsize = TCBHASHSIZE; 259 tcp_delacktime = TCPTV_DELACK; 260 tcp_keepinit = TCPTV_KEEP_INIT; 261 tcp_keepidle = TCPTV_KEEP_IDLE; 262 tcp_keepintvl = TCPTV_KEEPINTVL; 263 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 264 tcp_msl = TCPTV_MSL; 265 tcp_rexmit_min = TCPTV_MIN; 266 tcp_rexmit_slop = TCPTV_CPU_VAR; 267 tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 268 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 269 270 INP_INFO_LOCK_INIT(&tcbinfo, "tcp"); 271 LIST_INIT(&tcb); 272 tcbinfo.ipi_listhead = &tcb; 273 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 274 if (!powerof2(hashsize)) { 275 printf("WARNING: TCB hash size not a power of 2\n"); 276 hashsize = 512; /* safe default */ 277 } 278 tcp_tcbhashsize = hashsize; 279 tcbinfo.ipi_hashbase = hashinit(hashsize, M_PCB, 280 &tcbinfo.ipi_hashmask); 281 tcbinfo.ipi_porthashbase = hashinit(hashsize, M_PCB, 282 &tcbinfo.ipi_porthashmask); 283 tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb), 284 NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 285 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 286 #ifdef INET6 287 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 288 #else /* INET6 */ 289 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 290 #endif /* INET6 */ 291 if (max_protohdr < TCP_MINPROTOHDR) 292 max_protohdr = TCP_MINPROTOHDR; 293 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 294 panic("tcp_init"); 295 #undef TCP_MINPROTOHDR 296 /* 297 * These have to be type stable for the benefit of the timers. 298 */ 299 tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 300 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 301 uma_zone_set_max(tcpcb_zone, maxsockets); 302 tcp_tw_init(); 303 syncache_init(); 304 tcp_hc_init(); 305 tcp_reass_init(); 306 ISN_LOCK_INIT(); 307 callout_init(&isn_callout, CALLOUT_MPSAFE); 308 tcp_isn_tick(NULL); 309 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 310 SHUTDOWN_PRI_DEFAULT); 311 sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 312 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 313 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 314 EVENTHANDLER_PRI_ANY); 315 } 316 317 void 318 tcp_fini(void *xtp) 319 { 320 321 callout_stop(&isn_callout); 322 } 323 324 /* 325 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 326 * tcp_template used to store this data in mbufs, but we now recopy it out 327 * of the tcpcb each time to conserve mbufs. 328 */ 329 void 330 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 331 { 332 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 333 334 INP_LOCK_ASSERT(inp); 335 336 #ifdef INET6 337 if ((inp->inp_vflag & INP_IPV6) != 0) { 338 struct ip6_hdr *ip6; 339 340 ip6 = (struct ip6_hdr *)ip_ptr; 341 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 342 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 343 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 344 (IPV6_VERSION & IPV6_VERSION_MASK); 345 ip6->ip6_nxt = IPPROTO_TCP; 346 ip6->ip6_plen = sizeof(struct tcphdr); 347 ip6->ip6_src = inp->in6p_laddr; 348 ip6->ip6_dst = inp->in6p_faddr; 349 } else 350 #endif 351 { 352 struct ip *ip; 353 354 ip = (struct ip *)ip_ptr; 355 ip->ip_v = IPVERSION; 356 ip->ip_hl = 5; 357 ip->ip_tos = inp->inp_ip_tos; 358 ip->ip_len = 0; 359 ip->ip_id = 0; 360 ip->ip_off = 0; 361 ip->ip_ttl = inp->inp_ip_ttl; 362 ip->ip_sum = 0; 363 ip->ip_p = IPPROTO_TCP; 364 ip->ip_src = inp->inp_laddr; 365 ip->ip_dst = inp->inp_faddr; 366 } 367 th->th_sport = inp->inp_lport; 368 th->th_dport = inp->inp_fport; 369 th->th_seq = 0; 370 th->th_ack = 0; 371 th->th_x2 = 0; 372 th->th_off = 5; 373 th->th_flags = 0; 374 th->th_win = 0; 375 th->th_urp = 0; 376 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 377 } 378 379 /* 380 * Create template to be used to send tcp packets on a connection. 381 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 382 * use for this function is in keepalives, which use tcp_respond. 383 */ 384 struct tcptemp * 385 tcpip_maketemplate(struct inpcb *inp) 386 { 387 struct mbuf *m; 388 struct tcptemp *n; 389 390 m = m_get(M_DONTWAIT, MT_DATA); 391 if (m == NULL) 392 return (0); 393 m->m_len = sizeof(struct tcptemp); 394 n = mtod(m, struct tcptemp *); 395 396 tcpip_fillheaders(inp, (void *)&n->tt_ipgen, (void *)&n->tt_t); 397 return (n); 398 } 399 400 /* 401 * Send a single message to the TCP at address specified by 402 * the given TCP/IP header. If m == NULL, then we make a copy 403 * of the tcpiphdr at ti and send directly to the addressed host. 404 * This is used to force keep alive messages out using the TCP 405 * template for a connection. If flags are given then we send 406 * a message back to the TCP which originated the * segment ti, 407 * and discard the mbuf containing it and any other attached mbufs. 408 * 409 * In any case the ack and sequence number of the transmitted 410 * segment are as specified by the parameters. 411 * 412 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 413 */ 414 void 415 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 416 tcp_seq ack, tcp_seq seq, int flags) 417 { 418 int tlen; 419 int win = 0; 420 struct ip *ip; 421 struct tcphdr *nth; 422 #ifdef INET6 423 struct ip6_hdr *ip6; 424 int isipv6; 425 #endif /* INET6 */ 426 int ipflags = 0; 427 struct inpcb *inp; 428 429 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 430 431 #ifdef INET6 432 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 433 ip6 = ipgen; 434 #endif /* INET6 */ 435 ip = ipgen; 436 437 if (tp != NULL) { 438 inp = tp->t_inpcb; 439 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 440 INP_LOCK_ASSERT(inp); 441 } else 442 inp = NULL; 443 444 if (tp != NULL) { 445 if (!(flags & TH_RST)) { 446 win = sbspace(&inp->inp_socket->so_rcv); 447 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 448 win = (long)TCP_MAXWIN << tp->rcv_scale; 449 } 450 } 451 if (m == NULL) { 452 m = m_gethdr(M_DONTWAIT, MT_DATA); 453 if (m == NULL) 454 return; 455 tlen = 0; 456 m->m_data += max_linkhdr; 457 #ifdef INET6 458 if (isipv6) { 459 bcopy((caddr_t)ip6, mtod(m, caddr_t), 460 sizeof(struct ip6_hdr)); 461 ip6 = mtod(m, struct ip6_hdr *); 462 nth = (struct tcphdr *)(ip6 + 1); 463 } else 464 #endif /* INET6 */ 465 { 466 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 467 ip = mtod(m, struct ip *); 468 nth = (struct tcphdr *)(ip + 1); 469 } 470 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 471 flags = TH_ACK; 472 } else { 473 m_freem(m->m_next); 474 m->m_next = NULL; 475 m->m_data = (caddr_t)ipgen; 476 /* m_len is set later */ 477 tlen = 0; 478 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 479 #ifdef INET6 480 if (isipv6) { 481 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 482 nth = (struct tcphdr *)(ip6 + 1); 483 } else 484 #endif /* INET6 */ 485 { 486 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 487 nth = (struct tcphdr *)(ip + 1); 488 } 489 if (th != nth) { 490 /* 491 * this is usually a case when an extension header 492 * exists between the IPv6 header and the 493 * TCP header. 494 */ 495 nth->th_sport = th->th_sport; 496 nth->th_dport = th->th_dport; 497 } 498 xchg(nth->th_dport, nth->th_sport, n_short); 499 #undef xchg 500 } 501 #ifdef INET6 502 if (isipv6) { 503 ip6->ip6_flow = 0; 504 ip6->ip6_vfc = IPV6_VERSION; 505 ip6->ip6_nxt = IPPROTO_TCP; 506 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 507 tlen)); 508 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 509 } else 510 #endif 511 { 512 tlen += sizeof (struct tcpiphdr); 513 ip->ip_len = tlen; 514 ip->ip_ttl = ip_defttl; 515 if (path_mtu_discovery) 516 ip->ip_off |= IP_DF; 517 } 518 m->m_len = tlen; 519 m->m_pkthdr.len = tlen; 520 m->m_pkthdr.rcvif = NULL; 521 #ifdef MAC 522 if (inp != NULL) { 523 /* 524 * Packet is associated with a socket, so allow the 525 * label of the response to reflect the socket label. 526 */ 527 INP_LOCK_ASSERT(inp); 528 mac_create_mbuf_from_inpcb(inp, m); 529 } else { 530 /* 531 * Packet is not associated with a socket, so possibly 532 * update the label in place. 533 */ 534 mac_reflect_mbuf_tcp(m); 535 } 536 #endif 537 nth->th_seq = htonl(seq); 538 nth->th_ack = htonl(ack); 539 nth->th_x2 = 0; 540 nth->th_off = sizeof (struct tcphdr) >> 2; 541 nth->th_flags = flags; 542 if (tp != NULL) 543 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 544 else 545 nth->th_win = htons((u_short)win); 546 nth->th_urp = 0; 547 #ifdef INET6 548 if (isipv6) { 549 nth->th_sum = 0; 550 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 551 sizeof(struct ip6_hdr), 552 tlen - sizeof(struct ip6_hdr)); 553 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 554 NULL, NULL); 555 } else 556 #endif /* INET6 */ 557 { 558 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 559 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 560 m->m_pkthdr.csum_flags = CSUM_TCP; 561 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 562 } 563 #ifdef TCPDEBUG 564 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 565 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 566 #endif 567 #ifdef INET6 568 if (isipv6) 569 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 570 else 571 #endif /* INET6 */ 572 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 573 } 574 575 /* 576 * Create a new TCP control block, making an 577 * empty reassembly queue and hooking it to the argument 578 * protocol control block. The `inp' parameter must have 579 * come from the zone allocator set up in tcp_init(). 580 */ 581 struct tcpcb * 582 tcp_newtcpcb(struct inpcb *inp) 583 { 584 struct tcpcb_mem *tm; 585 struct tcpcb *tp; 586 #ifdef INET6 587 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 588 #endif /* INET6 */ 589 590 tm = uma_zalloc(tcpcb_zone, M_NOWAIT | M_ZERO); 591 if (tm == NULL) 592 return (NULL); 593 tp = &tm->tcb; 594 tp->t_timers = &tm->tt; 595 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 596 tp->t_maxseg = tp->t_maxopd = 597 #ifdef INET6 598 isipv6 ? tcp_v6mssdflt : 599 #endif /* INET6 */ 600 tcp_mssdflt; 601 602 /* Set up our timeouts. */ 603 if (NET_CALLOUT_MPSAFE) 604 callout_init_mtx(&tp->t_timers->tt_timer, &inp->inp_mtx, 605 CALLOUT_RETURNUNLOCKED); 606 else 607 callout_init_mtx(&tp->t_timers->tt_timer, &inp->inp_mtx, 608 (CALLOUT_RETURNUNLOCKED|CALLOUT_NETGIANT)); 609 610 if (tcp_do_rfc1323) 611 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 612 if (tcp_do_sack) 613 tp->t_flags |= TF_SACK_PERMIT; 614 TAILQ_INIT(&tp->snd_holes); 615 tp->t_inpcb = inp; /* XXX */ 616 /* 617 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 618 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 619 * reasonable initial retransmit time. 620 */ 621 tp->t_srtt = TCPTV_SRTTBASE; 622 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 623 tp->t_rttmin = tcp_rexmit_min; 624 tp->t_rxtcur = TCPTV_RTOBASE; 625 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 626 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 627 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 628 tp->t_rcvtime = ticks; 629 tp->t_bw_rtttime = ticks; 630 /* 631 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 632 * because the socket may be bound to an IPv6 wildcard address, 633 * which may match an IPv4-mapped IPv6 address. 634 */ 635 inp->inp_ip_ttl = ip_defttl; 636 inp->inp_ppcb = tp; 637 return (tp); /* XXX */ 638 } 639 640 /* 641 * Drop a TCP connection, reporting 642 * the specified error. If connection is synchronized, 643 * then send a RST to peer. 644 */ 645 struct tcpcb * 646 tcp_drop(struct tcpcb *tp, int errno) 647 { 648 struct socket *so = tp->t_inpcb->inp_socket; 649 650 INP_INFO_WLOCK_ASSERT(&tcbinfo); 651 INP_LOCK_ASSERT(tp->t_inpcb); 652 653 if (TCPS_HAVERCVDSYN(tp->t_state)) { 654 tp->t_state = TCPS_CLOSED; 655 (void) tcp_output(tp); 656 tcpstat.tcps_drops++; 657 } else 658 tcpstat.tcps_conndrops++; 659 if (errno == ETIMEDOUT && tp->t_softerror) 660 errno = tp->t_softerror; 661 so->so_error = errno; 662 return (tcp_close(tp)); 663 } 664 665 void 666 tcp_discardcb(struct tcpcb *tp) 667 { 668 struct tseg_qent *q; 669 struct inpcb *inp = tp->t_inpcb; 670 struct socket *so = inp->inp_socket; 671 #ifdef INET6 672 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 673 #endif /* INET6 */ 674 675 INP_LOCK_ASSERT(inp); 676 677 /* 678 * Make sure that all of our timers are stopped before we 679 * delete the PCB. 680 * 681 * XXX: callout_stop() may race and a callout may already 682 * try to obtain the INP_LOCK. Only callout_drain() would 683 * stop this but it would cause a LOR thus we can't use it. 684 * The tcp_timer() function contains a lot of checks to 685 * handle this case rather gracefully. 686 */ 687 tp->t_timers->tt_active = 0; 688 callout_stop(&tp->t_timers->tt_timer); 689 690 /* 691 * If we got enough samples through the srtt filter, 692 * save the rtt and rttvar in the routing entry. 693 * 'Enough' is arbitrarily defined as 4 rtt samples. 694 * 4 samples is enough for the srtt filter to converge 695 * to within enough % of the correct value; fewer samples 696 * and we could save a bogus rtt. The danger is not high 697 * as tcp quickly recovers from everything. 698 * XXX: Works very well but needs some more statistics! 699 */ 700 if (tp->t_rttupdated >= 4) { 701 struct hc_metrics_lite metrics; 702 u_long ssthresh; 703 704 bzero(&metrics, sizeof(metrics)); 705 /* 706 * Update the ssthresh always when the conditions below 707 * are satisfied. This gives us better new start value 708 * for the congestion avoidance for new connections. 709 * ssthresh is only set if packet loss occured on a session. 710 * 711 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 712 * being torn down. Ideally this code would not use 'so'. 713 */ 714 ssthresh = tp->snd_ssthresh; 715 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 716 /* 717 * convert the limit from user data bytes to 718 * packets then to packet data bytes. 719 */ 720 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 721 if (ssthresh < 2) 722 ssthresh = 2; 723 ssthresh *= (u_long)(tp->t_maxseg + 724 #ifdef INET6 725 (isipv6 ? sizeof (struct ip6_hdr) + 726 sizeof (struct tcphdr) : 727 #endif 728 sizeof (struct tcpiphdr) 729 #ifdef INET6 730 ) 731 #endif 732 ); 733 } else 734 ssthresh = 0; 735 metrics.rmx_ssthresh = ssthresh; 736 737 metrics.rmx_rtt = tp->t_srtt; 738 metrics.rmx_rttvar = tp->t_rttvar; 739 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 740 metrics.rmx_bandwidth = tp->snd_bandwidth; 741 metrics.rmx_cwnd = tp->snd_cwnd; 742 metrics.rmx_sendpipe = 0; 743 metrics.rmx_recvpipe = 0; 744 745 tcp_hc_update(&inp->inp_inc, &metrics); 746 } 747 748 /* free the reassembly queue, if any */ 749 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) { 750 LIST_REMOVE(q, tqe_q); 751 m_freem(q->tqe_m); 752 uma_zfree(tcp_reass_zone, q); 753 tp->t_segqlen--; 754 tcp_reass_qsize--; 755 } 756 tcp_free_sackholes(tp); 757 inp->inp_ppcb = NULL; 758 tp->t_inpcb = NULL; 759 uma_zfree(tcpcb_zone, tp); 760 } 761 762 /* 763 * Attempt to close a TCP control block, marking it as dropped, and freeing 764 * the socket if we hold the only reference. 765 */ 766 struct tcpcb * 767 tcp_close(struct tcpcb *tp) 768 { 769 struct inpcb *inp = tp->t_inpcb; 770 struct socket *so; 771 772 INP_INFO_WLOCK_ASSERT(&tcbinfo); 773 INP_LOCK_ASSERT(inp); 774 775 in_pcbdrop(inp); 776 tcpstat.tcps_closed++; 777 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 778 so = inp->inp_socket; 779 soisdisconnected(so); 780 if (inp->inp_vflag & INP_SOCKREF) { 781 KASSERT(so->so_state & SS_PROTOREF, 782 ("tcp_close: !SS_PROTOREF")); 783 inp->inp_vflag &= ~INP_SOCKREF; 784 INP_UNLOCK(inp); 785 ACCEPT_LOCK(); 786 SOCK_LOCK(so); 787 so->so_state &= ~SS_PROTOREF; 788 sofree(so); 789 return (NULL); 790 } 791 return (tp); 792 } 793 794 void 795 tcp_drain(void) 796 { 797 798 if (do_tcpdrain) { 799 struct inpcb *inpb; 800 struct tcpcb *tcpb; 801 struct tseg_qent *te; 802 803 /* 804 * Walk the tcpbs, if existing, and flush the reassembly queue, 805 * if there is one... 806 * XXX: The "Net/3" implementation doesn't imply that the TCP 807 * reassembly queue should be flushed, but in a situation 808 * where we're really low on mbufs, this is potentially 809 * usefull. 810 */ 811 INP_INFO_RLOCK(&tcbinfo); 812 LIST_FOREACH(inpb, tcbinfo.ipi_listhead, inp_list) { 813 if (inpb->inp_vflag & INP_TIMEWAIT) 814 continue; 815 INP_LOCK(inpb); 816 if ((tcpb = intotcpcb(inpb)) != NULL) { 817 while ((te = LIST_FIRST(&tcpb->t_segq)) 818 != NULL) { 819 LIST_REMOVE(te, tqe_q); 820 m_freem(te->tqe_m); 821 uma_zfree(tcp_reass_zone, te); 822 tcpb->t_segqlen--; 823 tcp_reass_qsize--; 824 } 825 tcp_clean_sackreport(tcpb); 826 } 827 INP_UNLOCK(inpb); 828 } 829 INP_INFO_RUNLOCK(&tcbinfo); 830 } 831 } 832 833 /* 834 * Notify a tcp user of an asynchronous error; 835 * store error as soft error, but wake up user 836 * (for now, won't do anything until can select for soft error). 837 * 838 * Do not wake up user since there currently is no mechanism for 839 * reporting soft errors (yet - a kqueue filter may be added). 840 */ 841 static struct inpcb * 842 tcp_notify(struct inpcb *inp, int error) 843 { 844 struct tcpcb *tp; 845 846 INP_INFO_WLOCK_ASSERT(&tcbinfo); 847 INP_LOCK_ASSERT(inp); 848 849 if ((inp->inp_vflag & INP_TIMEWAIT) || 850 (inp->inp_vflag & INP_DROPPED)) 851 return (inp); 852 853 tp = intotcpcb(inp); 854 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 855 856 /* 857 * Ignore some errors if we are hooked up. 858 * If connection hasn't completed, has retransmitted several times, 859 * and receives a second error, give up now. This is better 860 * than waiting a long time to establish a connection that 861 * can never complete. 862 */ 863 if (tp->t_state == TCPS_ESTABLISHED && 864 (error == EHOSTUNREACH || error == ENETUNREACH || 865 error == EHOSTDOWN)) { 866 return (inp); 867 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 868 tp->t_softerror) { 869 tp = tcp_drop(tp, error); 870 if (tp != NULL) 871 return (inp); 872 else 873 return (NULL); 874 } else { 875 tp->t_softerror = error; 876 return (inp); 877 } 878 #if 0 879 wakeup( &so->so_timeo); 880 sorwakeup(so); 881 sowwakeup(so); 882 #endif 883 } 884 885 static int 886 tcp_pcblist(SYSCTL_HANDLER_ARGS) 887 { 888 int error, i, n; 889 struct inpcb *inp, **inp_list; 890 inp_gen_t gencnt; 891 struct xinpgen xig; 892 893 /* 894 * The process of preparing the TCB list is too time-consuming and 895 * resource-intensive to repeat twice on every request. 896 */ 897 if (req->oldptr == NULL) { 898 n = tcbinfo.ipi_count; 899 req->oldidx = 2 * (sizeof xig) 900 + (n + n/8) * sizeof(struct xtcpcb); 901 return (0); 902 } 903 904 if (req->newptr != NULL) 905 return (EPERM); 906 907 /* 908 * OK, now we're committed to doing something. 909 */ 910 INP_INFO_RLOCK(&tcbinfo); 911 gencnt = tcbinfo.ipi_gencnt; 912 n = tcbinfo.ipi_count; 913 INP_INFO_RUNLOCK(&tcbinfo); 914 915 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 916 + n * sizeof(struct xtcpcb)); 917 if (error != 0) 918 return (error); 919 920 xig.xig_len = sizeof xig; 921 xig.xig_count = n; 922 xig.xig_gen = gencnt; 923 xig.xig_sogen = so_gencnt; 924 error = SYSCTL_OUT(req, &xig, sizeof xig); 925 if (error) 926 return (error); 927 928 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 929 if (inp_list == NULL) 930 return (ENOMEM); 931 932 INP_INFO_RLOCK(&tcbinfo); 933 for (inp = LIST_FIRST(tcbinfo.ipi_listhead), i = 0; inp != NULL && i 934 < n; inp = LIST_NEXT(inp, inp_list)) { 935 INP_LOCK(inp); 936 if (inp->inp_gencnt <= gencnt) { 937 /* 938 * XXX: This use of cr_cansee(), introduced with 939 * TCP state changes, is not quite right, but for 940 * now, better than nothing. 941 */ 942 if (inp->inp_vflag & INP_TIMEWAIT) { 943 if (intotw(inp) != NULL) 944 error = cr_cansee(req->td->td_ucred, 945 intotw(inp)->tw_cred); 946 else 947 error = EINVAL; /* Skip this inp. */ 948 } else 949 error = cr_canseesocket(req->td->td_ucred, 950 inp->inp_socket); 951 if (error == 0) 952 inp_list[i++] = inp; 953 } 954 INP_UNLOCK(inp); 955 } 956 INP_INFO_RUNLOCK(&tcbinfo); 957 n = i; 958 959 error = 0; 960 for (i = 0; i < n; i++) { 961 inp = inp_list[i]; 962 INP_LOCK(inp); 963 if (inp->inp_gencnt <= gencnt) { 964 struct xtcpcb xt; 965 void *inp_ppcb; 966 967 bzero(&xt, sizeof(xt)); 968 xt.xt_len = sizeof xt; 969 /* XXX should avoid extra copy */ 970 bcopy(inp, &xt.xt_inp, sizeof *inp); 971 inp_ppcb = inp->inp_ppcb; 972 if (inp_ppcb == NULL) 973 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 974 else if (inp->inp_vflag & INP_TIMEWAIT) { 975 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 976 xt.xt_tp.t_state = TCPS_TIME_WAIT; 977 } else 978 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 979 if (inp->inp_socket != NULL) 980 sotoxsocket(inp->inp_socket, &xt.xt_socket); 981 else { 982 bzero(&xt.xt_socket, sizeof xt.xt_socket); 983 xt.xt_socket.xso_protocol = IPPROTO_TCP; 984 } 985 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 986 INP_UNLOCK(inp); 987 error = SYSCTL_OUT(req, &xt, sizeof xt); 988 } else 989 INP_UNLOCK(inp); 990 991 } 992 if (!error) { 993 /* 994 * Give the user an updated idea of our state. 995 * If the generation differs from what we told 996 * her before, she knows that something happened 997 * while we were processing this request, and it 998 * might be necessary to retry. 999 */ 1000 INP_INFO_RLOCK(&tcbinfo); 1001 xig.xig_gen = tcbinfo.ipi_gencnt; 1002 xig.xig_sogen = so_gencnt; 1003 xig.xig_count = tcbinfo.ipi_count; 1004 INP_INFO_RUNLOCK(&tcbinfo); 1005 error = SYSCTL_OUT(req, &xig, sizeof xig); 1006 } 1007 free(inp_list, M_TEMP); 1008 return (error); 1009 } 1010 1011 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1012 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1013 1014 static int 1015 tcp_getcred(SYSCTL_HANDLER_ARGS) 1016 { 1017 struct xucred xuc; 1018 struct sockaddr_in addrs[2]; 1019 struct inpcb *inp; 1020 int error; 1021 1022 error = priv_check_cred(req->td->td_ucred, PRIV_NETINET_GETCRED, 1023 SUSER_ALLOWJAIL); 1024 if (error) 1025 return (error); 1026 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1027 if (error) 1028 return (error); 1029 INP_INFO_RLOCK(&tcbinfo); 1030 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 1031 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1032 if (inp == NULL) { 1033 error = ENOENT; 1034 goto outunlocked; 1035 } 1036 INP_LOCK(inp); 1037 if (inp->inp_socket == NULL) { 1038 error = ENOENT; 1039 goto out; 1040 } 1041 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1042 if (error) 1043 goto out; 1044 cru2x(inp->inp_socket->so_cred, &xuc); 1045 out: 1046 INP_UNLOCK(inp); 1047 outunlocked: 1048 INP_INFO_RUNLOCK(&tcbinfo); 1049 if (error == 0) 1050 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1051 return (error); 1052 } 1053 1054 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1055 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1056 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1057 1058 #ifdef INET6 1059 static int 1060 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1061 { 1062 struct xucred xuc; 1063 struct sockaddr_in6 addrs[2]; 1064 struct inpcb *inp; 1065 int error, mapped = 0; 1066 1067 error = priv_check_cred(req->td->td_ucred, PRIV_NETINET_GETCRED, 1068 SUSER_ALLOWJAIL); 1069 if (error) 1070 return (error); 1071 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1072 if (error) 1073 return (error); 1074 if ((error = sa6_embedscope(&addrs[0], ip6_use_defzone)) != 0 || 1075 (error = sa6_embedscope(&addrs[1], ip6_use_defzone)) != 0) { 1076 return (error); 1077 } 1078 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1079 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1080 mapped = 1; 1081 else 1082 return (EINVAL); 1083 } 1084 1085 INP_INFO_RLOCK(&tcbinfo); 1086 if (mapped == 1) 1087 inp = in_pcblookup_hash(&tcbinfo, 1088 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1089 addrs[1].sin6_port, 1090 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1091 addrs[0].sin6_port, 1092 0, NULL); 1093 else 1094 inp = in6_pcblookup_hash(&tcbinfo, 1095 &addrs[1].sin6_addr, addrs[1].sin6_port, 1096 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1097 if (inp == NULL) { 1098 error = ENOENT; 1099 goto outunlocked; 1100 } 1101 INP_LOCK(inp); 1102 if (inp->inp_socket == NULL) { 1103 error = ENOENT; 1104 goto out; 1105 } 1106 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1107 if (error) 1108 goto out; 1109 cru2x(inp->inp_socket->so_cred, &xuc); 1110 out: 1111 INP_UNLOCK(inp); 1112 outunlocked: 1113 INP_INFO_RUNLOCK(&tcbinfo); 1114 if (error == 0) 1115 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1116 return (error); 1117 } 1118 1119 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1120 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1121 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1122 #endif 1123 1124 1125 void 1126 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1127 { 1128 struct ip *ip = vip; 1129 struct tcphdr *th; 1130 struct in_addr faddr; 1131 struct inpcb *inp; 1132 struct tcpcb *tp; 1133 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1134 struct icmp *icp; 1135 struct in_conninfo inc; 1136 tcp_seq icmp_tcp_seq; 1137 int mtu; 1138 1139 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1140 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1141 return; 1142 1143 if (cmd == PRC_MSGSIZE) 1144 notify = tcp_mtudisc; 1145 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1146 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1147 notify = tcp_drop_syn_sent; 1148 /* 1149 * Redirects don't need to be handled up here. 1150 */ 1151 else if (PRC_IS_REDIRECT(cmd)) 1152 return; 1153 /* 1154 * Source quench is depreciated. 1155 */ 1156 else if (cmd == PRC_QUENCH) 1157 return; 1158 /* 1159 * Hostdead is ugly because it goes linearly through all PCBs. 1160 * XXX: We never get this from ICMP, otherwise it makes an 1161 * excellent DoS attack on machines with many connections. 1162 */ 1163 else if (cmd == PRC_HOSTDEAD) 1164 ip = NULL; 1165 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1166 return; 1167 if (ip != NULL) { 1168 icp = (struct icmp *)((caddr_t)ip 1169 - offsetof(struct icmp, icmp_ip)); 1170 th = (struct tcphdr *)((caddr_t)ip 1171 + (ip->ip_hl << 2)); 1172 INP_INFO_WLOCK(&tcbinfo); 1173 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1174 ip->ip_src, th->th_sport, 0, NULL); 1175 if (inp != NULL) { 1176 INP_LOCK(inp); 1177 if (!(inp->inp_vflag & INP_TIMEWAIT) && 1178 !(inp->inp_vflag & INP_DROPPED) && 1179 !(inp->inp_socket == NULL)) { 1180 icmp_tcp_seq = htonl(th->th_seq); 1181 tp = intotcpcb(inp); 1182 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1183 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1184 if (cmd == PRC_MSGSIZE) { 1185 /* 1186 * MTU discovery: 1187 * If we got a needfrag set the MTU 1188 * in the route to the suggested new 1189 * value (if given) and then notify. 1190 */ 1191 bzero(&inc, sizeof(inc)); 1192 inc.inc_flags = 0; /* IPv4 */ 1193 inc.inc_faddr = faddr; 1194 1195 mtu = ntohs(icp->icmp_nextmtu); 1196 /* 1197 * If no alternative MTU was 1198 * proposed, try the next smaller 1199 * one. ip->ip_len has already 1200 * been swapped in icmp_input(). 1201 */ 1202 if (!mtu) 1203 mtu = ip_next_mtu(ip->ip_len, 1204 1); 1205 if (mtu < max(296, (tcp_minmss) 1206 + sizeof(struct tcpiphdr))) 1207 mtu = 0; 1208 if (!mtu) 1209 mtu = tcp_mssdflt 1210 + sizeof(struct tcpiphdr); 1211 /* 1212 * Only cache the the MTU if it 1213 * is smaller than the interface 1214 * or route MTU. tcp_mtudisc() 1215 * will do right thing by itself. 1216 */ 1217 if (mtu <= tcp_maxmtu(&inc, NULL)) 1218 tcp_hc_updatemtu(&inc, mtu); 1219 } 1220 1221 inp = (*notify)(inp, inetctlerrmap[cmd]); 1222 } 1223 } 1224 if (inp != NULL) 1225 INP_UNLOCK(inp); 1226 } else { 1227 inc.inc_fport = th->th_dport; 1228 inc.inc_lport = th->th_sport; 1229 inc.inc_faddr = faddr; 1230 inc.inc_laddr = ip->ip_src; 1231 #ifdef INET6 1232 inc.inc_isipv6 = 0; 1233 #endif 1234 syncache_unreach(&inc, th); 1235 } 1236 INP_INFO_WUNLOCK(&tcbinfo); 1237 } else 1238 in_pcbnotifyall(&tcbinfo, faddr, inetctlerrmap[cmd], notify); 1239 } 1240 1241 #ifdef INET6 1242 void 1243 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1244 { 1245 struct tcphdr th; 1246 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1247 struct ip6_hdr *ip6; 1248 struct mbuf *m; 1249 struct ip6ctlparam *ip6cp = NULL; 1250 const struct sockaddr_in6 *sa6_src = NULL; 1251 int off; 1252 struct tcp_portonly { 1253 u_int16_t th_sport; 1254 u_int16_t th_dport; 1255 } *thp; 1256 1257 if (sa->sa_family != AF_INET6 || 1258 sa->sa_len != sizeof(struct sockaddr_in6)) 1259 return; 1260 1261 if (cmd == PRC_MSGSIZE) 1262 notify = tcp_mtudisc; 1263 else if (!PRC_IS_REDIRECT(cmd) && 1264 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1265 return; 1266 /* Source quench is depreciated. */ 1267 else if (cmd == PRC_QUENCH) 1268 return; 1269 1270 /* if the parameter is from icmp6, decode it. */ 1271 if (d != NULL) { 1272 ip6cp = (struct ip6ctlparam *)d; 1273 m = ip6cp->ip6c_m; 1274 ip6 = ip6cp->ip6c_ip6; 1275 off = ip6cp->ip6c_off; 1276 sa6_src = ip6cp->ip6c_src; 1277 } else { 1278 m = NULL; 1279 ip6 = NULL; 1280 off = 0; /* fool gcc */ 1281 sa6_src = &sa6_any; 1282 } 1283 1284 if (ip6 != NULL) { 1285 struct in_conninfo inc; 1286 /* 1287 * XXX: We assume that when IPV6 is non NULL, 1288 * M and OFF are valid. 1289 */ 1290 1291 /* check if we can safely examine src and dst ports */ 1292 if (m->m_pkthdr.len < off + sizeof(*thp)) 1293 return; 1294 1295 bzero(&th, sizeof(th)); 1296 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1297 1298 in6_pcbnotify(&tcbinfo, sa, th.th_dport, 1299 (struct sockaddr *)ip6cp->ip6c_src, 1300 th.th_sport, cmd, NULL, notify); 1301 1302 inc.inc_fport = th.th_dport; 1303 inc.inc_lport = th.th_sport; 1304 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1305 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1306 inc.inc_isipv6 = 1; 1307 INP_INFO_WLOCK(&tcbinfo); 1308 syncache_unreach(&inc, &th); 1309 INP_INFO_WUNLOCK(&tcbinfo); 1310 } else 1311 in6_pcbnotify(&tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1312 0, cmd, NULL, notify); 1313 } 1314 #endif /* INET6 */ 1315 1316 1317 /* 1318 * Following is where TCP initial sequence number generation occurs. 1319 * 1320 * There are two places where we must use initial sequence numbers: 1321 * 1. In SYN-ACK packets. 1322 * 2. In SYN packets. 1323 * 1324 * All ISNs for SYN-ACK packets are generated by the syncache. See 1325 * tcp_syncache.c for details. 1326 * 1327 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1328 * depends on this property. In addition, these ISNs should be 1329 * unguessable so as to prevent connection hijacking. To satisfy 1330 * the requirements of this situation, the algorithm outlined in 1331 * RFC 1948 is used, with only small modifications. 1332 * 1333 * Implementation details: 1334 * 1335 * Time is based off the system timer, and is corrected so that it 1336 * increases by one megabyte per second. This allows for proper 1337 * recycling on high speed LANs while still leaving over an hour 1338 * before rollover. 1339 * 1340 * As reading the *exact* system time is too expensive to be done 1341 * whenever setting up a TCP connection, we increment the time 1342 * offset in two ways. First, a small random positive increment 1343 * is added to isn_offset for each connection that is set up. 1344 * Second, the function tcp_isn_tick fires once per clock tick 1345 * and increments isn_offset as necessary so that sequence numbers 1346 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1347 * random positive increments serve only to ensure that the same 1348 * exact sequence number is never sent out twice (as could otherwise 1349 * happen when a port is recycled in less than the system tick 1350 * interval.) 1351 * 1352 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1353 * between seeding of isn_secret. This is normally set to zero, 1354 * as reseeding should not be necessary. 1355 * 1356 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1357 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1358 * general, this means holding an exclusive (write) lock. 1359 */ 1360 1361 #define ISN_BYTES_PER_SECOND 1048576 1362 #define ISN_STATIC_INCREMENT 4096 1363 #define ISN_RANDOM_INCREMENT (4096 - 1) 1364 1365 static u_char isn_secret[32]; 1366 static int isn_last_reseed; 1367 static u_int32_t isn_offset, isn_offset_old; 1368 static MD5_CTX isn_ctx; 1369 1370 tcp_seq 1371 tcp_new_isn(struct tcpcb *tp) 1372 { 1373 u_int32_t md5_buffer[4]; 1374 tcp_seq new_isn; 1375 1376 INP_LOCK_ASSERT(tp->t_inpcb); 1377 1378 ISN_LOCK(); 1379 /* Seed if this is the first use, reseed if requested. */ 1380 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1381 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1382 < (u_int)ticks))) { 1383 read_random(&isn_secret, sizeof(isn_secret)); 1384 isn_last_reseed = ticks; 1385 } 1386 1387 /* Compute the md5 hash and return the ISN. */ 1388 MD5Init(&isn_ctx); 1389 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1390 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1391 #ifdef INET6 1392 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1393 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1394 sizeof(struct in6_addr)); 1395 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1396 sizeof(struct in6_addr)); 1397 } else 1398 #endif 1399 { 1400 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1401 sizeof(struct in_addr)); 1402 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1403 sizeof(struct in_addr)); 1404 } 1405 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1406 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1407 new_isn = (tcp_seq) md5_buffer[0]; 1408 isn_offset += ISN_STATIC_INCREMENT + 1409 (arc4random() & ISN_RANDOM_INCREMENT); 1410 new_isn += isn_offset; 1411 ISN_UNLOCK(); 1412 return (new_isn); 1413 } 1414 1415 /* 1416 * Increment the offset to the next ISN_BYTES_PER_SECOND / hz boundary 1417 * to keep time flowing at a relatively constant rate. If the random 1418 * increments have already pushed us past the projected offset, do nothing. 1419 */ 1420 static void 1421 tcp_isn_tick(void *xtp) 1422 { 1423 u_int32_t projected_offset; 1424 1425 ISN_LOCK(); 1426 projected_offset = isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1427 1428 if (projected_offset > isn_offset) 1429 isn_offset = projected_offset; 1430 1431 isn_offset_old = isn_offset; 1432 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1433 ISN_UNLOCK(); 1434 } 1435 1436 /* 1437 * When a specific ICMP unreachable message is received and the 1438 * connection state is SYN-SENT, drop the connection. This behavior 1439 * is controlled by the icmp_may_rst sysctl. 1440 */ 1441 struct inpcb * 1442 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1443 { 1444 struct tcpcb *tp; 1445 1446 INP_INFO_WLOCK_ASSERT(&tcbinfo); 1447 INP_LOCK_ASSERT(inp); 1448 1449 if ((inp->inp_vflag & INP_TIMEWAIT) || 1450 (inp->inp_vflag & INP_DROPPED)) 1451 return (inp); 1452 1453 tp = intotcpcb(inp); 1454 if (tp->t_state != TCPS_SYN_SENT) 1455 return (inp); 1456 1457 tp = tcp_drop(tp, errno); 1458 if (tp != NULL) 1459 return (inp); 1460 else 1461 return (NULL); 1462 } 1463 1464 /* 1465 * When `need fragmentation' ICMP is received, update our idea of the MSS 1466 * based on the new value in the route. Also nudge TCP to send something, 1467 * since we know the packet we just sent was dropped. 1468 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1469 */ 1470 struct inpcb * 1471 tcp_mtudisc(struct inpcb *inp, int errno) 1472 { 1473 struct tcpcb *tp; 1474 struct socket *so = inp->inp_socket; 1475 u_int maxmtu; 1476 u_int romtu; 1477 int mss; 1478 #ifdef INET6 1479 int isipv6; 1480 #endif /* INET6 */ 1481 1482 INP_LOCK_ASSERT(inp); 1483 if ((inp->inp_vflag & INP_TIMEWAIT) || 1484 (inp->inp_vflag & INP_DROPPED)) 1485 return (inp); 1486 1487 tp = intotcpcb(inp); 1488 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1489 1490 #ifdef INET6 1491 isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1492 #endif 1493 maxmtu = tcp_hc_getmtu(&inp->inp_inc); /* IPv4 and IPv6 */ 1494 romtu = 1495 #ifdef INET6 1496 isipv6 ? tcp_maxmtu6(&inp->inp_inc, NULL) : 1497 #endif /* INET6 */ 1498 tcp_maxmtu(&inp->inp_inc, NULL); 1499 if (!maxmtu) 1500 maxmtu = romtu; 1501 else 1502 maxmtu = min(maxmtu, romtu); 1503 if (!maxmtu) { 1504 tp->t_maxopd = tp->t_maxseg = 1505 #ifdef INET6 1506 isipv6 ? tcp_v6mssdflt : 1507 #endif /* INET6 */ 1508 tcp_mssdflt; 1509 return (inp); 1510 } 1511 mss = maxmtu - 1512 #ifdef INET6 1513 (isipv6 ? sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1514 #endif /* INET6 */ 1515 sizeof(struct tcpiphdr) 1516 #ifdef INET6 1517 ) 1518 #endif /* INET6 */ 1519 ; 1520 1521 /* 1522 * XXX - The above conditional probably violates the TCP 1523 * spec. The problem is that, since we don't know the 1524 * other end's MSS, we are supposed to use a conservative 1525 * default. But, if we do that, then MTU discovery will 1526 * never actually take place, because the conservative 1527 * default is much less than the MTUs typically seen 1528 * on the Internet today. For the moment, we'll sweep 1529 * this under the carpet. 1530 * 1531 * The conservative default might not actually be a problem 1532 * if the only case this occurs is when sending an initial 1533 * SYN with options and data to a host we've never talked 1534 * to before. Then, they will reply with an MSS value which 1535 * will get recorded and the new parameters should get 1536 * recomputed. For Further Study. 1537 */ 1538 if (tp->t_maxopd <= mss) 1539 return (inp); 1540 tp->t_maxopd = mss; 1541 1542 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1543 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1544 mss -= TCPOLEN_TSTAMP_APPA; 1545 #if (MCLBYTES & (MCLBYTES - 1)) == 0 1546 if (mss > MCLBYTES) 1547 mss &= ~(MCLBYTES-1); 1548 #else 1549 if (mss > MCLBYTES) 1550 mss = mss / MCLBYTES * MCLBYTES; 1551 #endif 1552 if (so->so_snd.sb_hiwat < mss) 1553 mss = so->so_snd.sb_hiwat; 1554 1555 tp->t_maxseg = mss; 1556 1557 tcpstat.tcps_mturesent++; 1558 tp->t_rtttime = 0; 1559 tp->snd_nxt = tp->snd_una; 1560 tcp_free_sackholes(tp); 1561 tp->snd_recover = tp->snd_max; 1562 if (tp->t_flags & TF_SACK_PERMIT) 1563 EXIT_FASTRECOVERY(tp); 1564 tcp_output(tp); 1565 return (inp); 1566 } 1567 1568 /* 1569 * Look-up the routing entry to the peer of this inpcb. If no route 1570 * is found and it cannot be allocated, then return NULL. This routine 1571 * is called by TCP routines that access the rmx structure and by tcp_mss 1572 * to get the interface MTU. 1573 */ 1574 u_long 1575 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1576 { 1577 struct route sro; 1578 struct sockaddr_in *dst; 1579 struct ifnet *ifp; 1580 u_long maxmtu = 0; 1581 1582 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1583 1584 bzero(&sro, sizeof(sro)); 1585 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1586 dst = (struct sockaddr_in *)&sro.ro_dst; 1587 dst->sin_family = AF_INET; 1588 dst->sin_len = sizeof(*dst); 1589 dst->sin_addr = inc->inc_faddr; 1590 rtalloc_ign(&sro, RTF_CLONING); 1591 } 1592 if (sro.ro_rt != NULL) { 1593 ifp = sro.ro_rt->rt_ifp; 1594 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1595 maxmtu = ifp->if_mtu; 1596 else 1597 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1598 1599 /* Report additional interface capabilities. */ 1600 if (flags != NULL) { 1601 if (ifp->if_capenable & IFCAP_TSO4 && 1602 ifp->if_hwassist & CSUM_TSO) 1603 *flags |= CSUM_TSO; 1604 } 1605 RTFREE(sro.ro_rt); 1606 } 1607 return (maxmtu); 1608 } 1609 1610 #ifdef INET6 1611 u_long 1612 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1613 { 1614 struct route_in6 sro6; 1615 struct ifnet *ifp; 1616 u_long maxmtu = 0; 1617 1618 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1619 1620 bzero(&sro6, sizeof(sro6)); 1621 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1622 sro6.ro_dst.sin6_family = AF_INET6; 1623 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1624 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1625 rtalloc_ign((struct route *)&sro6, RTF_CLONING); 1626 } 1627 if (sro6.ro_rt != NULL) { 1628 ifp = sro6.ro_rt->rt_ifp; 1629 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1630 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1631 else 1632 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1633 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1634 1635 /* Report additional interface capabilities. */ 1636 if (flags != NULL) { 1637 if (ifp->if_capenable & IFCAP_TSO6 && 1638 ifp->if_hwassist & CSUM_TSO) 1639 *flags |= CSUM_TSO; 1640 } 1641 RTFREE(sro6.ro_rt); 1642 } 1643 1644 return (maxmtu); 1645 } 1646 #endif /* INET6 */ 1647 1648 #ifdef IPSEC 1649 /* compute ESP/AH header size for TCP, including outer IP header. */ 1650 size_t 1651 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1652 { 1653 struct inpcb *inp; 1654 struct mbuf *m; 1655 size_t hdrsiz; 1656 struct ip *ip; 1657 #ifdef INET6 1658 struct ip6_hdr *ip6; 1659 #endif 1660 struct tcphdr *th; 1661 1662 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1663 return (0); 1664 MGETHDR(m, M_DONTWAIT, MT_DATA); 1665 if (!m) 1666 return (0); 1667 1668 #ifdef INET6 1669 if ((inp->inp_vflag & INP_IPV6) != 0) { 1670 ip6 = mtod(m, struct ip6_hdr *); 1671 th = (struct tcphdr *)(ip6 + 1); 1672 m->m_pkthdr.len = m->m_len = 1673 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1674 tcpip_fillheaders(inp, ip6, th); 1675 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1676 } else 1677 #endif /* INET6 */ 1678 { 1679 ip = mtod(m, struct ip *); 1680 th = (struct tcphdr *)(ip + 1); 1681 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1682 tcpip_fillheaders(inp, ip, th); 1683 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1684 } 1685 1686 m_free(m); 1687 return (hdrsiz); 1688 } 1689 #endif /*IPSEC*/ 1690 1691 /* 1692 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1693 * 1694 * This code attempts to calculate the bandwidth-delay product as a 1695 * means of determining the optimal window size to maximize bandwidth, 1696 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1697 * routers. This code also does a fairly good job keeping RTTs in check 1698 * across slow links like modems. We implement an algorithm which is very 1699 * similar (but not meant to be) TCP/Vegas. The code operates on the 1700 * transmitter side of a TCP connection and so only effects the transmit 1701 * side of the connection. 1702 * 1703 * BACKGROUND: TCP makes no provision for the management of buffer space 1704 * at the end points or at the intermediate routers and switches. A TCP 1705 * stream, whether using NewReno or not, will eventually buffer as 1706 * many packets as it is able and the only reason this typically works is 1707 * due to the fairly small default buffers made available for a connection 1708 * (typicaly 16K or 32K). As machines use larger windows and/or window 1709 * scaling it is now fairly easy for even a single TCP connection to blow-out 1710 * all available buffer space not only on the local interface, but on 1711 * intermediate routers and switches as well. NewReno makes a misguided 1712 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1713 * then backing off, then steadily increasing the window again until another 1714 * failure occurs, ad-infinitum. This results in terrible oscillation that 1715 * is only made worse as network loads increase and the idea of intentionally 1716 * blowing out network buffers is, frankly, a terrible way to manage network 1717 * resources. 1718 * 1719 * It is far better to limit the transmit window prior to the failure 1720 * condition being achieved. There are two general ways to do this: First 1721 * you can 'scan' through different transmit window sizes and locate the 1722 * point where the RTT stops increasing, indicating that you have filled the 1723 * pipe, then scan backwards until you note that RTT stops decreasing, then 1724 * repeat ad-infinitum. This method works in principle but has severe 1725 * implementation issues due to RTT variances, timer granularity, and 1726 * instability in the algorithm which can lead to many false positives and 1727 * create oscillations as well as interact badly with other TCP streams 1728 * implementing the same algorithm. 1729 * 1730 * The second method is to limit the window to the bandwidth delay product 1731 * of the link. This is the method we implement. RTT variances and our 1732 * own manipulation of the congestion window, bwnd, can potentially 1733 * destabilize the algorithm. For this reason we have to stabilize the 1734 * elements used to calculate the window. We do this by using the minimum 1735 * observed RTT, the long term average of the observed bandwidth, and 1736 * by adding two segments worth of slop. It isn't perfect but it is able 1737 * to react to changing conditions and gives us a very stable basis on 1738 * which to extend the algorithm. 1739 */ 1740 void 1741 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1742 { 1743 u_long bw; 1744 u_long bwnd; 1745 int save_ticks; 1746 1747 INP_LOCK_ASSERT(tp->t_inpcb); 1748 1749 /* 1750 * If inflight_enable is disabled in the middle of a tcp connection, 1751 * make sure snd_bwnd is effectively disabled. 1752 */ 1753 if (tcp_inflight_enable == 0 || tp->t_rttlow < tcp_inflight_rttthresh) { 1754 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1755 tp->snd_bandwidth = 0; 1756 return; 1757 } 1758 1759 /* 1760 * Figure out the bandwidth. Due to the tick granularity this 1761 * is a very rough number and it MUST be averaged over a fairly 1762 * long period of time. XXX we need to take into account a link 1763 * that is not using all available bandwidth, but for now our 1764 * slop will ramp us up if this case occurs and the bandwidth later 1765 * increases. 1766 * 1767 * Note: if ticks rollover 'bw' may wind up negative. We must 1768 * effectively reset t_bw_rtttime for this case. 1769 */ 1770 save_ticks = ticks; 1771 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 1772 return; 1773 1774 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 1775 (save_ticks - tp->t_bw_rtttime); 1776 tp->t_bw_rtttime = save_ticks; 1777 tp->t_bw_rtseq = ack_seq; 1778 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 1779 return; 1780 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1781 1782 tp->snd_bandwidth = bw; 1783 1784 /* 1785 * Calculate the semi-static bandwidth delay product, plus two maximal 1786 * segments. The additional slop puts us squarely in the sweet 1787 * spot and also handles the bandwidth run-up case and stabilization. 1788 * Without the slop we could be locking ourselves into a lower 1789 * bandwidth. 1790 * 1791 * Situations Handled: 1792 * (1) Prevents over-queueing of packets on LANs, especially on 1793 * high speed LANs, allowing larger TCP buffers to be 1794 * specified, and also does a good job preventing 1795 * over-queueing of packets over choke points like modems 1796 * (at least for the transmit side). 1797 * 1798 * (2) Is able to handle changing network loads (bandwidth 1799 * drops so bwnd drops, bandwidth increases so bwnd 1800 * increases). 1801 * 1802 * (3) Theoretically should stabilize in the face of multiple 1803 * connections implementing the same algorithm (this may need 1804 * a little work). 1805 * 1806 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1807 * be adjusted with a sysctl but typically only needs to be 1808 * on very slow connections. A value no smaller then 5 1809 * should be used, but only reduce this default if you have 1810 * no other choice. 1811 */ 1812 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1813 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + tcp_inflight_stab * tp->t_maxseg / 10; 1814 #undef USERTT 1815 1816 if (tcp_inflight_debug > 0) { 1817 static int ltime; 1818 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1819 ltime = ticks; 1820 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1821 tp, 1822 bw, 1823 tp->t_rttbest, 1824 tp->t_srtt, 1825 bwnd 1826 ); 1827 } 1828 } 1829 if ((long)bwnd < tcp_inflight_min) 1830 bwnd = tcp_inflight_min; 1831 if (bwnd > tcp_inflight_max) 1832 bwnd = tcp_inflight_max; 1833 if ((long)bwnd < tp->t_maxseg * 2) 1834 bwnd = tp->t_maxseg * 2; 1835 tp->snd_bwnd = bwnd; 1836 } 1837 1838 #ifdef TCP_SIGNATURE 1839 /* 1840 * Callback function invoked by m_apply() to digest TCP segment data 1841 * contained within an mbuf chain. 1842 */ 1843 static int 1844 tcp_signature_apply(void *fstate, void *data, u_int len) 1845 { 1846 1847 MD5Update(fstate, (u_char *)data, len); 1848 return (0); 1849 } 1850 1851 /* 1852 * Compute TCP-MD5 hash of a TCPv4 segment. (RFC2385) 1853 * 1854 * Parameters: 1855 * m pointer to head of mbuf chain 1856 * off0 offset to TCP header within the mbuf chain 1857 * len length of TCP segment data, excluding options 1858 * optlen length of TCP segment options 1859 * buf pointer to storage for computed MD5 digest 1860 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 1861 * 1862 * We do this over ip, tcphdr, segment data, and the key in the SADB. 1863 * When called from tcp_input(), we can be sure that th_sum has been 1864 * zeroed out and verified already. 1865 * 1866 * This function is for IPv4 use only. Calling this function with an 1867 * IPv6 packet in the mbuf chain will yield undefined results. 1868 * 1869 * Return 0 if successful, otherwise return -1. 1870 * 1871 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 1872 * search with the destination IP address, and a 'magic SPI' to be 1873 * determined by the application. This is hardcoded elsewhere to 1179 1874 * right now. Another branch of this code exists which uses the SPD to 1875 * specify per-application flows but it is unstable. 1876 */ 1877 int 1878 tcp_signature_compute(struct mbuf *m, int off0, int len, int optlen, 1879 u_char *buf, u_int direction) 1880 { 1881 union sockaddr_union dst; 1882 struct ippseudo ippseudo; 1883 MD5_CTX ctx; 1884 int doff; 1885 struct ip *ip; 1886 struct ipovly *ipovly; 1887 struct secasvar *sav; 1888 struct tcphdr *th; 1889 u_short savecsum; 1890 1891 KASSERT(m != NULL, ("NULL mbuf chain")); 1892 KASSERT(buf != NULL, ("NULL signature pointer")); 1893 1894 /* Extract the destination from the IP header in the mbuf. */ 1895 ip = mtod(m, struct ip *); 1896 bzero(&dst, sizeof(union sockaddr_union)); 1897 dst.sa.sa_len = sizeof(struct sockaddr_in); 1898 dst.sa.sa_family = AF_INET; 1899 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 1900 ip->ip_src : ip->ip_dst; 1901 1902 /* Look up an SADB entry which matches the address of the peer. */ 1903 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 1904 if (sav == NULL) { 1905 printf("%s: SADB lookup failed for %s\n", __func__, 1906 inet_ntoa(dst.sin.sin_addr)); 1907 return (EINVAL); 1908 } 1909 1910 MD5Init(&ctx); 1911 ipovly = (struct ipovly *)ip; 1912 th = (struct tcphdr *)((u_char *)ip + off0); 1913 doff = off0 + sizeof(struct tcphdr) + optlen; 1914 1915 /* 1916 * Step 1: Update MD5 hash with IP pseudo-header. 1917 * 1918 * XXX The ippseudo header MUST be digested in network byte order, 1919 * or else we'll fail the regression test. Assume all fields we've 1920 * been doing arithmetic on have been in host byte order. 1921 * XXX One cannot depend on ipovly->ih_len here. When called from 1922 * tcp_output(), the underlying ip_len member has not yet been set. 1923 */ 1924 ippseudo.ippseudo_src = ipovly->ih_src; 1925 ippseudo.ippseudo_dst = ipovly->ih_dst; 1926 ippseudo.ippseudo_pad = 0; 1927 ippseudo.ippseudo_p = IPPROTO_TCP; 1928 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + optlen); 1929 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 1930 1931 /* 1932 * Step 2: Update MD5 hash with TCP header, excluding options. 1933 * The TCP checksum must be set to zero. 1934 */ 1935 savecsum = th->th_sum; 1936 th->th_sum = 0; 1937 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 1938 th->th_sum = savecsum; 1939 1940 /* 1941 * Step 3: Update MD5 hash with TCP segment data. 1942 * Use m_apply() to avoid an early m_pullup(). 1943 */ 1944 if (len > 0) 1945 m_apply(m, doff, len, tcp_signature_apply, &ctx); 1946 1947 /* 1948 * Step 4: Update MD5 hash with shared secret. 1949 */ 1950 MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); 1951 MD5Final(buf, &ctx); 1952 1953 key_sa_recordxfer(sav, m); 1954 KEY_FREESAV(&sav); 1955 return (0); 1956 } 1957 #endif /* TCP_SIGNATURE */ 1958 1959 static int 1960 sysctl_drop(SYSCTL_HANDLER_ARGS) 1961 { 1962 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 1963 struct sockaddr_storage addrs[2]; 1964 struct inpcb *inp; 1965 struct tcpcb *tp; 1966 struct tcptw *tw; 1967 struct sockaddr_in *fin, *lin; 1968 #ifdef INET6 1969 struct sockaddr_in6 *fin6, *lin6; 1970 struct in6_addr f6, l6; 1971 #endif 1972 int error; 1973 1974 inp = NULL; 1975 fin = lin = NULL; 1976 #ifdef INET6 1977 fin6 = lin6 = NULL; 1978 #endif 1979 error = 0; 1980 1981 if (req->oldptr != NULL || req->oldlen != 0) 1982 return (EINVAL); 1983 if (req->newptr == NULL) 1984 return (EPERM); 1985 if (req->newlen < sizeof(addrs)) 1986 return (ENOMEM); 1987 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 1988 if (error) 1989 return (error); 1990 1991 switch (addrs[0].ss_family) { 1992 #ifdef INET6 1993 case AF_INET6: 1994 fin6 = (struct sockaddr_in6 *)&addrs[0]; 1995 lin6 = (struct sockaddr_in6 *)&addrs[1]; 1996 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 1997 lin6->sin6_len != sizeof(struct sockaddr_in6)) 1998 return (EINVAL); 1999 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2000 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2001 return (EINVAL); 2002 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2003 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2004 fin = (struct sockaddr_in *)&addrs[0]; 2005 lin = (struct sockaddr_in *)&addrs[1]; 2006 break; 2007 } 2008 error = sa6_embedscope(fin6, ip6_use_defzone); 2009 if (error) 2010 return (error); 2011 error = sa6_embedscope(lin6, ip6_use_defzone); 2012 if (error) 2013 return (error); 2014 break; 2015 #endif 2016 case AF_INET: 2017 fin = (struct sockaddr_in *)&addrs[0]; 2018 lin = (struct sockaddr_in *)&addrs[1]; 2019 if (fin->sin_len != sizeof(struct sockaddr_in) || 2020 lin->sin_len != sizeof(struct sockaddr_in)) 2021 return (EINVAL); 2022 break; 2023 default: 2024 return (EINVAL); 2025 } 2026 INP_INFO_WLOCK(&tcbinfo); 2027 switch (addrs[0].ss_family) { 2028 #ifdef INET6 2029 case AF_INET6: 2030 inp = in6_pcblookup_hash(&tcbinfo, &f6, fin6->sin6_port, 2031 &l6, lin6->sin6_port, 0, NULL); 2032 break; 2033 #endif 2034 case AF_INET: 2035 inp = in_pcblookup_hash(&tcbinfo, fin->sin_addr, fin->sin_port, 2036 lin->sin_addr, lin->sin_port, 0, NULL); 2037 break; 2038 } 2039 if (inp != NULL) { 2040 INP_LOCK(inp); 2041 if (inp->inp_vflag & INP_TIMEWAIT) { 2042 /* 2043 * XXXRW: There currently exists a state where an 2044 * inpcb is present, but its timewait state has been 2045 * discarded. For now, don't allow dropping of this 2046 * type of inpcb. 2047 */ 2048 tw = intotw(inp); 2049 if (tw != NULL) 2050 tcp_twclose(tw, 0); 2051 } else if (!(inp->inp_vflag & INP_DROPPED) && 2052 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2053 tp = intotcpcb(inp); 2054 tcp_drop(tp, ECONNABORTED); 2055 } 2056 INP_UNLOCK(inp); 2057 } else 2058 error = ESRCH; 2059 INP_INFO_WUNLOCK(&tcbinfo); 2060 return (error); 2061 } 2062 2063 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2064 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2065 0, sysctl_drop, "", "Drop TCP connection"); 2066 2067 /* 2068 * Generate a standardized TCP log line for use throughout the 2069 * tcp subsystem. Memory allocation is done with M_NOWAIT to 2070 * allow use in the interrupt context. 2071 * 2072 * NB: The caller MUST free(s, M_TCPLOG) the returned string. 2073 * NB: The function may return NULL if memory allocation failed. 2074 * 2075 * Due to header inclusion and ordering limitations the struct ip 2076 * and ip6_hdr pointers have to be passed as void pointers. 2077 */ 2078 char * 2079 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2080 void *ip6hdr) 2081 { 2082 char *s, *sp; 2083 size_t size; 2084 struct ip *ip; 2085 #ifdef INET6 2086 struct ip6_hdr *ip6; 2087 2088 ip6 = (struct ip6_hdr *)ip6hdr; 2089 #endif /* INET6 */ 2090 ip = (struct ip *)ip4hdr; 2091 2092 /* 2093 * XXX: The size calculation is evil. 2094 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags <RST>" 2095 */ 2096 #ifdef INET6 2097 size = 5 + 2 * (INET6_ADDRSTRLEN + 10) + 12 + 12 * 4 + 1; 2098 #else 2099 size = 5 + 2 * (sizeof("192.168.172.190") + 10) + 12 + 12 *4 + 1; 2100 #endif /* INET6 */ 2101 2102 s = sp = malloc(size, M_TCPLOG, (M_ZERO|M_NOWAIT)); 2103 if (s == NULL) 2104 return (NULL); 2105 2106 strcat(s, "TCP: ["); 2107 sp = s + strlen(s); 2108 2109 if (inc && inc->inc_isipv6 == 0) { 2110 inet_ntoa_r(inc->inc_faddr, sp); 2111 sp = s + strlen(s); 2112 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2113 sp = s + strlen(s); 2114 inet_ntoa_r(inc->inc_laddr, sp); 2115 sp = s + strlen(s); 2116 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2117 #ifdef INET6 2118 } else if (inc) { 2119 ip6_sprintf(sp, &inc->inc6_faddr); 2120 sp = s + strlen(s); 2121 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2122 sp = s + strlen(s); 2123 ip6_sprintf(sp, &inc->inc6_laddr); 2124 sp = s + strlen(s); 2125 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2126 } else if (ip6 && th) { 2127 ip6_sprintf(sp, &ip6->ip6_src); 2128 sp = s + strlen(s); 2129 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2130 sp = s + strlen(s); 2131 ip6_sprintf(sp, &ip6->ip6_dst); 2132 sp = s + strlen(s); 2133 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2134 #endif /* INET6 */ 2135 } else if (ip && th) { 2136 inet_ntoa_r(ip->ip_src, sp); 2137 sp = s + strlen(s); 2138 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2139 sp = s + strlen(s); 2140 inet_ntoa_r(ip->ip_dst, sp); 2141 sp = s + strlen(s); 2142 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2143 } else { 2144 free(s, M_TCPLOG); 2145 return (NULL); 2146 } 2147 sp = s + strlen(s); 2148 if (th) 2149 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS); 2150 if (s[size] != '\0') 2151 panic("%s: string too long", __func__); 2152 return (s); 2153 } 2154