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 #include "opt_tcp_sack.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/callout.h> 44 #include <sys/kernel.h> 45 #include <sys/sysctl.h> 46 #include <sys/mac.h> 47 #include <sys/malloc.h> 48 #include <sys/mbuf.h> 49 #ifdef INET6 50 #include <sys/domain.h> 51 #endif 52 #include <sys/proc.h> 53 #include <sys/socket.h> 54 #include <sys/socketvar.h> 55 #include <sys/protosw.h> 56 #include <sys/random.h> 57 58 #include <vm/uma.h> 59 60 #include <net/route.h> 61 #include <net/if.h> 62 63 #include <netinet/in.h> 64 #include <netinet/in_systm.h> 65 #include <netinet/ip.h> 66 #ifdef INET6 67 #include <netinet/ip6.h> 68 #endif 69 #include <netinet/in_pcb.h> 70 #ifdef INET6 71 #include <netinet6/in6_pcb.h> 72 #endif 73 #include <netinet/in_var.h> 74 #include <netinet/ip_var.h> 75 #ifdef INET6 76 #include <netinet6/ip6_var.h> 77 #include <netinet6/scope6_var.h> 78 #include <netinet6/nd6.h> 79 #endif 80 #include <netinet/ip_icmp.h> 81 #include <netinet/tcp.h> 82 #include <netinet/tcp_fsm.h> 83 #include <netinet/tcp_seq.h> 84 #include <netinet/tcp_timer.h> 85 #include <netinet/tcp_var.h> 86 #ifdef INET6 87 #include <netinet6/tcp6_var.h> 88 #endif 89 #include <netinet/tcpip.h> 90 #ifdef TCPDEBUG 91 #include <netinet/tcp_debug.h> 92 #endif 93 #include <netinet6/ip6protosw.h> 94 95 #ifdef IPSEC 96 #include <netinet6/ipsec.h> 97 #ifdef INET6 98 #include <netinet6/ipsec6.h> 99 #endif 100 #include <netkey/key.h> 101 #endif /*IPSEC*/ 102 103 #ifdef FAST_IPSEC 104 #include <netipsec/ipsec.h> 105 #include <netipsec/xform.h> 106 #ifdef INET6 107 #include <netipsec/ipsec6.h> 108 #endif 109 #include <netipsec/key.h> 110 #define IPSEC 111 #endif /*FAST_IPSEC*/ 112 113 #include <machine/in_cksum.h> 114 #include <sys/md5.h> 115 116 int tcp_mssdflt = TCP_MSS; 117 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 118 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size"); 119 120 #ifdef INET6 121 int tcp_v6mssdflt = TCP6_MSS; 122 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 123 CTLFLAG_RW, &tcp_v6mssdflt , 0, 124 "Default TCP Maximum Segment Size for IPv6"); 125 #endif 126 127 /* 128 * Minimum MSS we accept and use. This prevents DoS attacks where 129 * we are forced to a ridiculous low MSS like 20 and send hundreds 130 * of packets instead of one. The effect scales with the available 131 * bandwidth and quickly saturates the CPU and network interface 132 * with packet generation and sending. Set to zero to disable MINMSS 133 * checking. This setting prevents us from sending too small packets. 134 */ 135 int tcp_minmss = TCP_MINMSS; 136 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 137 &tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 138 /* 139 * Number of TCP segments per second we accept from remote host 140 * before we start to calculate average segment size. If average 141 * segment size drops below the minimum TCP MSS we assume a DoS 142 * attack and reset+drop the connection. Care has to be taken not to 143 * set this value too small to not kill interactive type connections 144 * (telnet, SSH) which send many small packets. 145 */ 146 int tcp_minmssoverload = TCP_MINMSSOVERLOAD; 147 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmssoverload, CTLFLAG_RW, 148 &tcp_minmssoverload , 0, "Number of TCP Segments per Second allowed to" 149 "be under the MINMSS Size"); 150 151 #if 0 152 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 153 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 154 &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time"); 155 #endif 156 157 int tcp_do_rfc1323 = 1; 158 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 159 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions"); 160 161 static int tcp_tcbhashsize = 0; 162 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 163 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 164 165 static int do_tcpdrain = 1; 166 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 167 "Enable tcp_drain routine for extra help when low on mbufs"); 168 169 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 170 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 171 172 static int icmp_may_rst = 1; 173 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 174 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 175 176 static int tcp_isn_reseed_interval = 0; 177 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 178 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 179 180 static int maxtcptw; 181 SYSCTL_INT(_net_inet_tcp, OID_AUTO, maxtcptw, CTLFLAG_RDTUN, 182 &maxtcptw, 0, "Maximum number of compressed TCP TIME_WAIT entries"); 183 184 /* 185 * TCP bandwidth limiting sysctls. Note that the default lower bound of 186 * 1024 exists only for debugging. A good production default would be 187 * something like 6100. 188 */ 189 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0, 190 "TCP inflight data limiting"); 191 192 static int tcp_inflight_enable = 1; 193 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, enable, CTLFLAG_RW, 194 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 195 196 static int tcp_inflight_debug = 0; 197 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW, 198 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 199 200 static int tcp_inflight_rttthresh; 201 SYSCTL_PROC(_net_inet_tcp_inflight, OID_AUTO, rttthresh, CTLTYPE_INT|CTLFLAG_RW, 202 &tcp_inflight_rttthresh, 0, sysctl_msec_to_ticks, "I", 203 "RTT threshold below which inflight will deactivate itself"); 204 205 static int tcp_inflight_min = 6144; 206 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, min, CTLFLAG_RW, 207 &tcp_inflight_min, 0, "Lower-bound for TCP inflight window"); 208 209 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 210 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, max, CTLFLAG_RW, 211 &tcp_inflight_max, 0, "Upper-bound for TCP inflight window"); 212 213 static int tcp_inflight_stab = 20; 214 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, stab, CTLFLAG_RW, 215 &tcp_inflight_stab, 0, "Inflight Algorithm Stabilization 20 = 2 packets"); 216 217 uma_zone_t sack_hole_zone; 218 219 static struct inpcb *tcp_notify(struct inpcb *, int); 220 static void tcp_isn_tick(void *); 221 222 /* 223 * Target size of TCP PCB hash tables. Must be a power of two. 224 * 225 * Note that this can be overridden by the kernel environment 226 * variable net.inet.tcp.tcbhashsize 227 */ 228 #ifndef TCBHASHSIZE 229 #define TCBHASHSIZE 512 230 #endif 231 232 /* 233 * XXX 234 * Callouts should be moved into struct tcp directly. They are currently 235 * separate because the tcpcb structure is exported to userland for sysctl 236 * parsing purposes, which do not know about callouts. 237 */ 238 struct tcpcb_mem { 239 struct tcpcb tcb; 240 struct callout tcpcb_mem_rexmt, tcpcb_mem_persist, tcpcb_mem_keep; 241 struct callout tcpcb_mem_2msl, tcpcb_mem_delack; 242 }; 243 244 static uma_zone_t tcpcb_zone; 245 static uma_zone_t tcptw_zone; 246 struct callout isn_callout; 247 static struct mtx isn_mtx; 248 249 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 250 #define ISN_LOCK() mtx_lock(&isn_mtx) 251 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 252 253 /* 254 * TCP initialization. 255 */ 256 static void 257 tcp_zone_change(void *tag) 258 { 259 260 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 261 uma_zone_set_max(tcpcb_zone, maxsockets); 262 uma_zone_set_max(tcptw_zone, maxsockets / 5); 263 } 264 265 void 266 tcp_init(void) 267 { 268 int hashsize = TCBHASHSIZE; 269 270 tcp_delacktime = TCPTV_DELACK; 271 tcp_keepinit = TCPTV_KEEP_INIT; 272 tcp_keepidle = TCPTV_KEEP_IDLE; 273 tcp_keepintvl = TCPTV_KEEPINTVL; 274 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 275 tcp_msl = TCPTV_MSL; 276 tcp_rexmit_min = TCPTV_MIN; 277 tcp_rexmit_slop = TCPTV_CPU_VAR; 278 tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 279 280 INP_INFO_LOCK_INIT(&tcbinfo, "tcp"); 281 LIST_INIT(&tcb); 282 tcbinfo.listhead = &tcb; 283 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 284 if (!powerof2(hashsize)) { 285 printf("WARNING: TCB hash size not a power of 2\n"); 286 hashsize = 512; /* safe default */ 287 } 288 tcp_tcbhashsize = hashsize; 289 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask); 290 tcbinfo.porthashbase = hashinit(hashsize, M_PCB, 291 &tcbinfo.porthashmask); 292 tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb), 293 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 294 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 295 #ifdef INET6 296 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 297 #else /* INET6 */ 298 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 299 #endif /* INET6 */ 300 if (max_protohdr < TCP_MINPROTOHDR) 301 max_protohdr = TCP_MINPROTOHDR; 302 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 303 panic("tcp_init"); 304 #undef TCP_MINPROTOHDR 305 /* 306 * These have to be type stable for the benefit of the timers. 307 */ 308 tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 309 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 310 uma_zone_set_max(tcpcb_zone, maxsockets); 311 TUNABLE_INT_FETCH("net.inet.tcp.maxtcptw", &maxtcptw); 312 if (maxtcptw == 0) 313 maxtcptw = maxsockets / 5; 314 tcptw_zone = uma_zcreate("tcptw", sizeof(struct tcptw), 315 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 316 uma_zone_set_max(tcptw_zone, maxtcptw); 317 tcp_timer_init(); 318 syncache_init(); 319 tcp_hc_init(); 320 tcp_reass_init(); 321 ISN_LOCK_INIT(); 322 callout_init(&isn_callout, CALLOUT_MPSAFE); 323 tcp_isn_tick(NULL); 324 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 325 SHUTDOWN_PRI_DEFAULT); 326 sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 327 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 328 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 329 EVENTHANDLER_PRI_ANY); 330 } 331 332 void 333 tcp_fini(void *xtp) 334 { 335 336 callout_stop(&isn_callout); 337 } 338 339 /* 340 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 341 * tcp_template used to store this data in mbufs, but we now recopy it out 342 * of the tcpcb each time to conserve mbufs. 343 */ 344 void 345 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 346 { 347 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 348 349 INP_LOCK_ASSERT(inp); 350 351 #ifdef INET6 352 if ((inp->inp_vflag & INP_IPV6) != 0) { 353 struct ip6_hdr *ip6; 354 355 ip6 = (struct ip6_hdr *)ip_ptr; 356 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 357 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 358 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 359 (IPV6_VERSION & IPV6_VERSION_MASK); 360 ip6->ip6_nxt = IPPROTO_TCP; 361 ip6->ip6_plen = sizeof(struct tcphdr); 362 ip6->ip6_src = inp->in6p_laddr; 363 ip6->ip6_dst = inp->in6p_faddr; 364 } else 365 #endif 366 { 367 struct ip *ip; 368 369 ip = (struct ip *)ip_ptr; 370 ip->ip_v = IPVERSION; 371 ip->ip_hl = 5; 372 ip->ip_tos = inp->inp_ip_tos; 373 ip->ip_len = 0; 374 ip->ip_id = 0; 375 ip->ip_off = 0; 376 ip->ip_ttl = inp->inp_ip_ttl; 377 ip->ip_sum = 0; 378 ip->ip_p = IPPROTO_TCP; 379 ip->ip_src = inp->inp_laddr; 380 ip->ip_dst = inp->inp_faddr; 381 } 382 th->th_sport = inp->inp_lport; 383 th->th_dport = inp->inp_fport; 384 th->th_seq = 0; 385 th->th_ack = 0; 386 th->th_x2 = 0; 387 th->th_off = 5; 388 th->th_flags = 0; 389 th->th_win = 0; 390 th->th_urp = 0; 391 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 392 } 393 394 /* 395 * Create template to be used to send tcp packets on a connection. 396 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 397 * use for this function is in keepalives, which use tcp_respond. 398 */ 399 struct tcptemp * 400 tcpip_maketemplate(struct inpcb *inp) 401 { 402 struct mbuf *m; 403 struct tcptemp *n; 404 405 m = m_get(M_DONTWAIT, MT_DATA); 406 if (m == NULL) 407 return (0); 408 m->m_len = sizeof(struct tcptemp); 409 n = mtod(m, struct tcptemp *); 410 411 tcpip_fillheaders(inp, (void *)&n->tt_ipgen, (void *)&n->tt_t); 412 return (n); 413 } 414 415 /* 416 * Send a single message to the TCP at address specified by 417 * the given TCP/IP header. If m == NULL, then we make a copy 418 * of the tcpiphdr at ti and send directly to the addressed host. 419 * This is used to force keep alive messages out using the TCP 420 * template for a connection. If flags are given then we send 421 * a message back to the TCP which originated the * segment ti, 422 * and discard the mbuf containing it and any other attached mbufs. 423 * 424 * In any case the ack and sequence number of the transmitted 425 * segment are as specified by the parameters. 426 * 427 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 428 */ 429 void 430 tcp_respond(struct tcpcb *tp, void *ipgen, register struct tcphdr *th, 431 register struct mbuf *m, tcp_seq ack, tcp_seq seq, int flags) 432 { 433 register int tlen; 434 int win = 0; 435 struct ip *ip; 436 struct tcphdr *nth; 437 #ifdef INET6 438 struct ip6_hdr *ip6; 439 int isipv6; 440 #endif /* INET6 */ 441 int ipflags = 0; 442 struct inpcb *inp; 443 444 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 445 446 #ifdef INET6 447 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 448 ip6 = ipgen; 449 #endif /* INET6 */ 450 ip = ipgen; 451 452 if (tp != NULL) { 453 inp = tp->t_inpcb; 454 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 455 INP_INFO_WLOCK_ASSERT(&tcbinfo); 456 INP_LOCK_ASSERT(inp); 457 } else 458 inp = NULL; 459 460 if (tp != NULL) { 461 if (!(flags & TH_RST)) { 462 win = sbspace(&inp->inp_socket->so_rcv); 463 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 464 win = (long)TCP_MAXWIN << tp->rcv_scale; 465 } 466 } 467 if (m == NULL) { 468 m = m_gethdr(M_DONTWAIT, MT_DATA); 469 if (m == NULL) 470 return; 471 tlen = 0; 472 m->m_data += max_linkhdr; 473 #ifdef INET6 474 if (isipv6) { 475 bcopy((caddr_t)ip6, mtod(m, caddr_t), 476 sizeof(struct ip6_hdr)); 477 ip6 = mtod(m, struct ip6_hdr *); 478 nth = (struct tcphdr *)(ip6 + 1); 479 } else 480 #endif /* INET6 */ 481 { 482 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 483 ip = mtod(m, struct ip *); 484 nth = (struct tcphdr *)(ip + 1); 485 } 486 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 487 flags = TH_ACK; 488 } else { 489 m_freem(m->m_next); 490 m->m_next = NULL; 491 m->m_data = (caddr_t)ipgen; 492 /* m_len is set later */ 493 tlen = 0; 494 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 495 #ifdef INET6 496 if (isipv6) { 497 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 498 nth = (struct tcphdr *)(ip6 + 1); 499 } else 500 #endif /* INET6 */ 501 { 502 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 503 nth = (struct tcphdr *)(ip + 1); 504 } 505 if (th != nth) { 506 /* 507 * this is usually a case when an extension header 508 * exists between the IPv6 header and the 509 * TCP header. 510 */ 511 nth->th_sport = th->th_sport; 512 nth->th_dport = th->th_dport; 513 } 514 xchg(nth->th_dport, nth->th_sport, n_short); 515 #undef xchg 516 } 517 #ifdef INET6 518 if (isipv6) { 519 ip6->ip6_flow = 0; 520 ip6->ip6_vfc = IPV6_VERSION; 521 ip6->ip6_nxt = IPPROTO_TCP; 522 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 523 tlen)); 524 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 525 } else 526 #endif 527 { 528 tlen += sizeof (struct tcpiphdr); 529 ip->ip_len = tlen; 530 ip->ip_ttl = ip_defttl; 531 if (path_mtu_discovery) 532 ip->ip_off |= IP_DF; 533 } 534 m->m_len = tlen; 535 m->m_pkthdr.len = tlen; 536 m->m_pkthdr.rcvif = NULL; 537 #ifdef MAC 538 if (inp != NULL) { 539 /* 540 * Packet is associated with a socket, so allow the 541 * label of the response to reflect the socket label. 542 */ 543 INP_LOCK_ASSERT(inp); 544 mac_create_mbuf_from_inpcb(inp, m); 545 } else { 546 /* 547 * Packet is not associated with a socket, so possibly 548 * update the label in place. 549 */ 550 mac_reflect_mbuf_tcp(m); 551 } 552 #endif 553 nth->th_seq = htonl(seq); 554 nth->th_ack = htonl(ack); 555 nth->th_x2 = 0; 556 nth->th_off = sizeof (struct tcphdr) >> 2; 557 nth->th_flags = flags; 558 if (tp != NULL) 559 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 560 else 561 nth->th_win = htons((u_short)win); 562 nth->th_urp = 0; 563 #ifdef INET6 564 if (isipv6) { 565 nth->th_sum = 0; 566 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 567 sizeof(struct ip6_hdr), 568 tlen - sizeof(struct ip6_hdr)); 569 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 570 NULL, NULL); 571 } else 572 #endif /* INET6 */ 573 { 574 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 575 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 576 m->m_pkthdr.csum_flags = CSUM_TCP; 577 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 578 } 579 #ifdef TCPDEBUG 580 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 581 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 582 #endif 583 #ifdef INET6 584 if (isipv6) 585 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 586 else 587 #endif /* INET6 */ 588 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 589 } 590 591 /* 592 * Create a new TCP control block, making an 593 * empty reassembly queue and hooking it to the argument 594 * protocol control block. The `inp' parameter must have 595 * come from the zone allocator set up in tcp_init(). 596 */ 597 struct tcpcb * 598 tcp_newtcpcb(struct inpcb *inp) 599 { 600 struct tcpcb_mem *tm; 601 struct tcpcb *tp; 602 #ifdef INET6 603 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 604 #endif /* INET6 */ 605 606 tm = uma_zalloc(tcpcb_zone, M_NOWAIT | M_ZERO); 607 if (tm == NULL) 608 return (NULL); 609 tp = &tm->tcb; 610 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 611 tp->t_maxseg = tp->t_maxopd = 612 #ifdef INET6 613 isipv6 ? tcp_v6mssdflt : 614 #endif /* INET6 */ 615 tcp_mssdflt; 616 617 /* Set up our timeouts. */ 618 callout_init(tp->tt_rexmt = &tm->tcpcb_mem_rexmt, NET_CALLOUT_MPSAFE); 619 callout_init(tp->tt_persist = &tm->tcpcb_mem_persist, NET_CALLOUT_MPSAFE); 620 callout_init(tp->tt_keep = &tm->tcpcb_mem_keep, NET_CALLOUT_MPSAFE); 621 callout_init(tp->tt_2msl = &tm->tcpcb_mem_2msl, NET_CALLOUT_MPSAFE); 622 callout_init(tp->tt_delack = &tm->tcpcb_mem_delack, NET_CALLOUT_MPSAFE); 623 624 if (tcp_do_rfc1323) 625 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 626 tp->sack_enable = tcp_do_sack; 627 TAILQ_INIT(&tp->snd_holes); 628 tp->t_inpcb = inp; /* XXX */ 629 /* 630 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 631 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 632 * reasonable initial retransmit time. 633 */ 634 tp->t_srtt = TCPTV_SRTTBASE; 635 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 636 tp->t_rttmin = tcp_rexmit_min; 637 tp->t_rxtcur = TCPTV_RTOBASE; 638 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 639 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 640 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 641 tp->t_rcvtime = ticks; 642 tp->t_bw_rtttime = ticks; 643 /* 644 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 645 * because the socket may be bound to an IPv6 wildcard address, 646 * which may match an IPv4-mapped IPv6 address. 647 */ 648 inp->inp_ip_ttl = ip_defttl; 649 inp->inp_ppcb = tp; 650 return (tp); /* XXX */ 651 } 652 653 /* 654 * Drop a TCP connection, reporting 655 * the specified error. If connection is synchronized, 656 * then send a RST to peer. 657 */ 658 struct tcpcb * 659 tcp_drop(struct tcpcb *tp, int errno) 660 { 661 struct socket *so = tp->t_inpcb->inp_socket; 662 663 INP_INFO_WLOCK_ASSERT(&tcbinfo); 664 INP_LOCK_ASSERT(tp->t_inpcb); 665 666 if (TCPS_HAVERCVDSYN(tp->t_state)) { 667 tp->t_state = TCPS_CLOSED; 668 (void) tcp_output(tp); 669 tcpstat.tcps_drops++; 670 } else 671 tcpstat.tcps_conndrops++; 672 if (errno == ETIMEDOUT && tp->t_softerror) 673 errno = tp->t_softerror; 674 so->so_error = errno; 675 return (tcp_close(tp)); 676 } 677 678 void 679 tcp_discardcb(struct tcpcb *tp) 680 { 681 struct tseg_qent *q; 682 struct inpcb *inp = tp->t_inpcb; 683 struct socket *so = inp->inp_socket; 684 #ifdef INET6 685 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 686 #endif /* INET6 */ 687 688 /* 689 * XXXRW: This is all very well and good, but actually, we might be 690 * discarding the tcpcb after the socket is gone, so we can't do 691 * this: 692 KASSERT(so != NULL, ("tcp_discardcb: so == NULL")); 693 */ 694 INP_LOCK_ASSERT(inp); 695 696 /* 697 * Make sure that all of our timers are stopped before we 698 * delete the PCB. 699 */ 700 callout_stop(tp->tt_rexmt); 701 callout_stop(tp->tt_persist); 702 callout_stop(tp->tt_keep); 703 callout_stop(tp->tt_2msl); 704 callout_stop(tp->tt_delack); 705 706 /* 707 * If we got enough samples through the srtt filter, 708 * save the rtt and rttvar in the routing entry. 709 * 'Enough' is arbitrarily defined as 4 rtt samples. 710 * 4 samples is enough for the srtt filter to converge 711 * to within enough % of the correct value; fewer samples 712 * and we could save a bogus rtt. The danger is not high 713 * as tcp quickly recovers from everything. 714 * XXX: Works very well but needs some more statistics! 715 */ 716 if (tp->t_rttupdated >= 4) { 717 struct hc_metrics_lite metrics; 718 u_long ssthresh; 719 720 bzero(&metrics, sizeof(metrics)); 721 /* 722 * Update the ssthresh always when the conditions below 723 * are satisfied. This gives us better new start value 724 * for the congestion avoidance for new connections. 725 * ssthresh is only set if packet loss occured on a session. 726 */ 727 ssthresh = tp->snd_ssthresh; 728 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 729 /* 730 * convert the limit from user data bytes to 731 * packets then to packet data bytes. 732 */ 733 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 734 if (ssthresh < 2) 735 ssthresh = 2; 736 ssthresh *= (u_long)(tp->t_maxseg + 737 #ifdef INET6 738 (isipv6 ? sizeof (struct ip6_hdr) + 739 sizeof (struct tcphdr) : 740 #endif 741 sizeof (struct tcpiphdr) 742 #ifdef INET6 743 ) 744 #endif 745 ); 746 } else 747 ssthresh = 0; 748 metrics.rmx_ssthresh = ssthresh; 749 750 metrics.rmx_rtt = tp->t_srtt; 751 metrics.rmx_rttvar = tp->t_rttvar; 752 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 753 metrics.rmx_bandwidth = tp->snd_bandwidth; 754 metrics.rmx_cwnd = tp->snd_cwnd; 755 metrics.rmx_sendpipe = 0; 756 metrics.rmx_recvpipe = 0; 757 758 tcp_hc_update(&inp->inp_inc, &metrics); 759 } 760 761 /* free the reassembly queue, if any */ 762 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) { 763 LIST_REMOVE(q, tqe_q); 764 m_freem(q->tqe_m); 765 uma_zfree(tcp_reass_zone, q); 766 tp->t_segqlen--; 767 tcp_reass_qsize--; 768 } 769 tcp_free_sackholes(tp); 770 inp->inp_ppcb = NULL; 771 tp->t_inpcb = NULL; 772 uma_zfree(tcpcb_zone, tp); 773 774 /* 775 * XXXRW: This seems a bit unclean. 776 */ 777 if (so != NULL) 778 soisdisconnected(so); 779 } 780 781 /* 782 * Attempt to close a TCP control block, marking it as dropped, and freeing 783 * the socket if we hold the only reference. 784 */ 785 struct tcpcb * 786 tcp_close(struct tcpcb *tp) 787 { 788 struct inpcb *inp = tp->t_inpcb; 789 struct socket *so; 790 791 INP_INFO_WLOCK_ASSERT(&tcbinfo); 792 INP_LOCK_ASSERT(inp); 793 794 in_pcbdrop(inp); 795 tcpstat.tcps_closed++; 796 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 797 so = inp->inp_socket; 798 soisdisconnected(so); 799 if (inp->inp_vflag & INP_SOCKREF) { 800 KASSERT(so->so_state & SS_PROTOREF, 801 ("tcp_close: !SS_PROTOREF")); 802 inp->inp_vflag &= ~INP_SOCKREF; 803 tcp_discardcb(tp); 804 #ifdef INET6 805 if (inp->inp_vflag & INP_IPV6PROTO) { 806 in6_pcbdetach(inp); 807 in6_pcbfree(inp); 808 } else { 809 #endif 810 in_pcbdetach(inp); 811 in_pcbfree(inp); 812 #ifdef INET6 813 } 814 #endif 815 ACCEPT_LOCK(); 816 SOCK_LOCK(so); 817 so->so_state &= ~SS_PROTOREF; 818 sofree(so); 819 return (NULL); 820 } 821 return (tp); 822 } 823 824 void 825 tcp_drain(void) 826 { 827 828 if (do_tcpdrain) { 829 struct inpcb *inpb; 830 struct tcpcb *tcpb; 831 struct tseg_qent *te; 832 833 /* 834 * Walk the tcpbs, if existing, and flush the reassembly queue, 835 * if there is one... 836 * XXX: The "Net/3" implementation doesn't imply that the TCP 837 * reassembly queue should be flushed, but in a situation 838 * where we're really low on mbufs, this is potentially 839 * usefull. 840 */ 841 INP_INFO_RLOCK(&tcbinfo); 842 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) { 843 if (inpb->inp_vflag & INP_TIMEWAIT) 844 continue; 845 INP_LOCK(inpb); 846 if ((tcpb = intotcpcb(inpb)) != NULL) { 847 while ((te = LIST_FIRST(&tcpb->t_segq)) 848 != NULL) { 849 LIST_REMOVE(te, tqe_q); 850 m_freem(te->tqe_m); 851 uma_zfree(tcp_reass_zone, te); 852 tcpb->t_segqlen--; 853 tcp_reass_qsize--; 854 } 855 tcp_clean_sackreport(tcpb); 856 } 857 INP_UNLOCK(inpb); 858 } 859 INP_INFO_RUNLOCK(&tcbinfo); 860 } 861 } 862 863 /* 864 * Notify a tcp user of an asynchronous error; 865 * store error as soft error, but wake up user 866 * (for now, won't do anything until can select for soft error). 867 * 868 * Do not wake up user since there currently is no mechanism for 869 * reporting soft errors (yet - a kqueue filter may be added). 870 */ 871 static struct inpcb * 872 tcp_notify(struct inpcb *inp, int error) 873 { 874 struct tcpcb *tp; 875 876 INP_INFO_WLOCK_ASSERT(&tcbinfo); 877 INP_LOCK_ASSERT(inp); 878 879 if ((inp->inp_vflag & INP_TIMEWAIT) || 880 (inp->inp_vflag & INP_DROPPED)) 881 return (inp); 882 883 tp = intotcpcb(inp); 884 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 885 886 /* 887 * Ignore some errors if we are hooked up. 888 * If connection hasn't completed, has retransmitted several times, 889 * and receives a second error, give up now. This is better 890 * than waiting a long time to establish a connection that 891 * can never complete. 892 */ 893 if (tp->t_state == TCPS_ESTABLISHED && 894 (error == EHOSTUNREACH || error == ENETUNREACH || 895 error == EHOSTDOWN)) { 896 return (inp); 897 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 898 tp->t_softerror) { 899 tp = tcp_drop(tp, error); 900 if (tp != NULL) 901 return (inp); 902 else 903 return (NULL); 904 } else { 905 tp->t_softerror = error; 906 return (inp); 907 } 908 #if 0 909 wakeup( &so->so_timeo); 910 sorwakeup(so); 911 sowwakeup(so); 912 #endif 913 } 914 915 static int 916 tcp_pcblist(SYSCTL_HANDLER_ARGS) 917 { 918 int error, i, n; 919 struct inpcb *inp, **inp_list; 920 inp_gen_t gencnt; 921 struct xinpgen xig; 922 923 /* 924 * The process of preparing the TCB list is too time-consuming and 925 * resource-intensive to repeat twice on every request. 926 */ 927 if (req->oldptr == NULL) { 928 n = tcbinfo.ipi_count; 929 req->oldidx = 2 * (sizeof xig) 930 + (n + n/8) * sizeof(struct xtcpcb); 931 return (0); 932 } 933 934 if (req->newptr != NULL) 935 return (EPERM); 936 937 /* 938 * OK, now we're committed to doing something. 939 */ 940 INP_INFO_RLOCK(&tcbinfo); 941 gencnt = tcbinfo.ipi_gencnt; 942 n = tcbinfo.ipi_count; 943 INP_INFO_RUNLOCK(&tcbinfo); 944 945 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 946 + n * sizeof(struct xtcpcb)); 947 if (error != 0) 948 return (error); 949 950 xig.xig_len = sizeof xig; 951 xig.xig_count = n; 952 xig.xig_gen = gencnt; 953 xig.xig_sogen = so_gencnt; 954 error = SYSCTL_OUT(req, &xig, sizeof xig); 955 if (error) 956 return (error); 957 958 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 959 if (inp_list == NULL) 960 return (ENOMEM); 961 962 INP_INFO_RLOCK(&tcbinfo); 963 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp != NULL && i < n; 964 inp = LIST_NEXT(inp, inp_list)) { 965 INP_LOCK(inp); 966 if (inp->inp_gencnt <= gencnt) { 967 /* 968 * XXX: This use of cr_cansee(), introduced with 969 * TCP state changes, is not quite right, but for 970 * now, better than nothing. 971 */ 972 if (inp->inp_vflag & INP_TIMEWAIT) { 973 if (intotw(inp) != NULL) 974 error = cr_cansee(req->td->td_ucred, 975 intotw(inp)->tw_cred); 976 else 977 error = EINVAL; /* Skip this inp. */ 978 } else 979 error = cr_canseesocket(req->td->td_ucred, 980 inp->inp_socket); 981 if (error == 0) 982 inp_list[i++] = inp; 983 } 984 INP_UNLOCK(inp); 985 } 986 INP_INFO_RUNLOCK(&tcbinfo); 987 n = i; 988 989 error = 0; 990 for (i = 0; i < n; i++) { 991 inp = inp_list[i]; 992 if (inp->inp_gencnt <= gencnt) { 993 struct xtcpcb xt; 994 void *inp_ppcb; 995 996 bzero(&xt, sizeof(xt)); 997 xt.xt_len = sizeof xt; 998 /* XXX should avoid extra copy */ 999 bcopy(inp, &xt.xt_inp, sizeof *inp); 1000 inp_ppcb = inp->inp_ppcb; 1001 if (inp_ppcb == NULL) 1002 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1003 else if (inp->inp_vflag & INP_TIMEWAIT) { 1004 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1005 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1006 } else 1007 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1008 if (inp->inp_socket != NULL) 1009 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1010 else { 1011 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1012 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1013 } 1014 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1015 error = SYSCTL_OUT(req, &xt, sizeof xt); 1016 } 1017 } 1018 if (!error) { 1019 /* 1020 * Give the user an updated idea of our state. 1021 * If the generation differs from what we told 1022 * her before, she knows that something happened 1023 * while we were processing this request, and it 1024 * might be necessary to retry. 1025 */ 1026 INP_INFO_RLOCK(&tcbinfo); 1027 xig.xig_gen = tcbinfo.ipi_gencnt; 1028 xig.xig_sogen = so_gencnt; 1029 xig.xig_count = tcbinfo.ipi_count; 1030 INP_INFO_RUNLOCK(&tcbinfo); 1031 error = SYSCTL_OUT(req, &xig, sizeof xig); 1032 } 1033 free(inp_list, M_TEMP); 1034 return (error); 1035 } 1036 1037 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1038 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1039 1040 static int 1041 tcp_getcred(SYSCTL_HANDLER_ARGS) 1042 { 1043 struct xucred xuc; 1044 struct sockaddr_in addrs[2]; 1045 struct inpcb *inp; 1046 int error; 1047 1048 error = suser_cred(req->td->td_ucred, SUSER_ALLOWJAIL); 1049 if (error) 1050 return (error); 1051 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1052 if (error) 1053 return (error); 1054 INP_INFO_RLOCK(&tcbinfo); 1055 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 1056 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1057 if (inp == NULL) { 1058 error = ENOENT; 1059 goto outunlocked; 1060 } 1061 INP_LOCK(inp); 1062 if (inp->inp_socket == NULL) { 1063 error = ENOENT; 1064 goto out; 1065 } 1066 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1067 if (error) 1068 goto out; 1069 cru2x(inp->inp_socket->so_cred, &xuc); 1070 out: 1071 INP_UNLOCK(inp); 1072 outunlocked: 1073 INP_INFO_RUNLOCK(&tcbinfo); 1074 if (error == 0) 1075 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1076 return (error); 1077 } 1078 1079 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1080 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1081 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1082 1083 #ifdef INET6 1084 static int 1085 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1086 { 1087 struct xucred xuc; 1088 struct sockaddr_in6 addrs[2]; 1089 struct inpcb *inp; 1090 int error, mapped = 0; 1091 1092 error = suser_cred(req->td->td_ucred, SUSER_ALLOWJAIL); 1093 if (error) 1094 return (error); 1095 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1096 if (error) 1097 return (error); 1098 if ((error = sa6_embedscope(&addrs[0], ip6_use_defzone)) != 0 || 1099 (error = sa6_embedscope(&addrs[1], ip6_use_defzone)) != 0) { 1100 return (error); 1101 } 1102 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1103 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1104 mapped = 1; 1105 else 1106 return (EINVAL); 1107 } 1108 1109 INP_INFO_RLOCK(&tcbinfo); 1110 if (mapped == 1) 1111 inp = in_pcblookup_hash(&tcbinfo, 1112 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1113 addrs[1].sin6_port, 1114 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1115 addrs[0].sin6_port, 1116 0, NULL); 1117 else 1118 inp = in6_pcblookup_hash(&tcbinfo, 1119 &addrs[1].sin6_addr, addrs[1].sin6_port, 1120 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1121 if (inp == NULL) { 1122 error = ENOENT; 1123 goto outunlocked; 1124 } 1125 INP_LOCK(inp); 1126 if (inp->inp_socket == NULL) { 1127 error = ENOENT; 1128 goto out; 1129 } 1130 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1131 if (error) 1132 goto out; 1133 cru2x(inp->inp_socket->so_cred, &xuc); 1134 out: 1135 INP_UNLOCK(inp); 1136 outunlocked: 1137 INP_INFO_RUNLOCK(&tcbinfo); 1138 if (error == 0) 1139 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1140 return (error); 1141 } 1142 1143 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1144 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1145 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1146 #endif 1147 1148 1149 void 1150 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1151 { 1152 struct ip *ip = vip; 1153 struct tcphdr *th; 1154 struct in_addr faddr; 1155 struct inpcb *inp; 1156 struct tcpcb *tp; 1157 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1158 struct icmp *icp; 1159 struct in_conninfo inc; 1160 tcp_seq icmp_tcp_seq; 1161 int mtu; 1162 1163 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1164 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1165 return; 1166 1167 if (cmd == PRC_MSGSIZE) 1168 notify = tcp_mtudisc; 1169 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1170 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1171 notify = tcp_drop_syn_sent; 1172 /* 1173 * Redirects don't need to be handled up here. 1174 */ 1175 else if (PRC_IS_REDIRECT(cmd)) 1176 return; 1177 /* 1178 * Source quench is depreciated. 1179 */ 1180 else if (cmd == PRC_QUENCH) 1181 return; 1182 /* 1183 * Hostdead is ugly because it goes linearly through all PCBs. 1184 * XXX: We never get this from ICMP, otherwise it makes an 1185 * excellent DoS attack on machines with many connections. 1186 */ 1187 else if (cmd == PRC_HOSTDEAD) 1188 ip = NULL; 1189 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1190 return; 1191 if (ip != NULL) { 1192 icp = (struct icmp *)((caddr_t)ip 1193 - offsetof(struct icmp, icmp_ip)); 1194 th = (struct tcphdr *)((caddr_t)ip 1195 + (ip->ip_hl << 2)); 1196 INP_INFO_WLOCK(&tcbinfo); 1197 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1198 ip->ip_src, th->th_sport, 0, NULL); 1199 if (inp != NULL) { 1200 INP_LOCK(inp); 1201 if (!(inp->inp_vflag & INP_TIMEWAIT) && 1202 !(inp->inp_vflag & INP_DROPPED) && 1203 !(inp->inp_socket == NULL)) { 1204 icmp_tcp_seq = htonl(th->th_seq); 1205 tp = intotcpcb(inp); 1206 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1207 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1208 if (cmd == PRC_MSGSIZE) { 1209 /* 1210 * MTU discovery: 1211 * If we got a needfrag set the MTU 1212 * in the route to the suggested new 1213 * value (if given) and then notify. 1214 */ 1215 bzero(&inc, sizeof(inc)); 1216 inc.inc_flags = 0; /* IPv4 */ 1217 inc.inc_faddr = faddr; 1218 1219 mtu = ntohs(icp->icmp_nextmtu); 1220 /* 1221 * If no alternative MTU was 1222 * proposed, try the next smaller 1223 * one. ip->ip_len has already 1224 * been swapped in icmp_input(). 1225 */ 1226 if (!mtu) 1227 mtu = ip_next_mtu(ip->ip_len, 1228 1); 1229 if (mtu < max(296, (tcp_minmss) 1230 + sizeof(struct tcpiphdr))) 1231 mtu = 0; 1232 if (!mtu) 1233 mtu = tcp_mssdflt 1234 + sizeof(struct tcpiphdr); 1235 /* 1236 * Only cache the the MTU if it 1237 * is smaller than the interface 1238 * or route MTU. tcp_mtudisc() 1239 * will do right thing by itself. 1240 */ 1241 if (mtu <= tcp_maxmtu(&inc)) 1242 tcp_hc_updatemtu(&inc, mtu); 1243 } 1244 1245 inp = (*notify)(inp, inetctlerrmap[cmd]); 1246 } 1247 } 1248 if (inp != NULL) 1249 INP_UNLOCK(inp); 1250 } else { 1251 inc.inc_fport = th->th_dport; 1252 inc.inc_lport = th->th_sport; 1253 inc.inc_faddr = faddr; 1254 inc.inc_laddr = ip->ip_src; 1255 #ifdef INET6 1256 inc.inc_isipv6 = 0; 1257 #endif 1258 syncache_unreach(&inc, th); 1259 } 1260 INP_INFO_WUNLOCK(&tcbinfo); 1261 } else 1262 in_pcbnotifyall(&tcbinfo, faddr, inetctlerrmap[cmd], notify); 1263 } 1264 1265 #ifdef INET6 1266 void 1267 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1268 { 1269 struct tcphdr th; 1270 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1271 struct ip6_hdr *ip6; 1272 struct mbuf *m; 1273 struct ip6ctlparam *ip6cp = NULL; 1274 const struct sockaddr_in6 *sa6_src = NULL; 1275 int off; 1276 struct tcp_portonly { 1277 u_int16_t th_sport; 1278 u_int16_t th_dport; 1279 } *thp; 1280 1281 if (sa->sa_family != AF_INET6 || 1282 sa->sa_len != sizeof(struct sockaddr_in6)) 1283 return; 1284 1285 if (cmd == PRC_MSGSIZE) 1286 notify = tcp_mtudisc; 1287 else if (!PRC_IS_REDIRECT(cmd) && 1288 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1289 return; 1290 /* Source quench is depreciated. */ 1291 else if (cmd == PRC_QUENCH) 1292 return; 1293 1294 /* if the parameter is from icmp6, decode it. */ 1295 if (d != NULL) { 1296 ip6cp = (struct ip6ctlparam *)d; 1297 m = ip6cp->ip6c_m; 1298 ip6 = ip6cp->ip6c_ip6; 1299 off = ip6cp->ip6c_off; 1300 sa6_src = ip6cp->ip6c_src; 1301 } else { 1302 m = NULL; 1303 ip6 = NULL; 1304 off = 0; /* fool gcc */ 1305 sa6_src = &sa6_any; 1306 } 1307 1308 if (ip6 != NULL) { 1309 struct in_conninfo inc; 1310 /* 1311 * XXX: We assume that when IPV6 is non NULL, 1312 * M and OFF are valid. 1313 */ 1314 1315 /* check if we can safely examine src and dst ports */ 1316 if (m->m_pkthdr.len < off + sizeof(*thp)) 1317 return; 1318 1319 bzero(&th, sizeof(th)); 1320 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1321 1322 in6_pcbnotify(&tcbinfo, sa, th.th_dport, 1323 (struct sockaddr *)ip6cp->ip6c_src, 1324 th.th_sport, cmd, NULL, notify); 1325 1326 inc.inc_fport = th.th_dport; 1327 inc.inc_lport = th.th_sport; 1328 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1329 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1330 inc.inc_isipv6 = 1; 1331 INP_INFO_WLOCK(&tcbinfo); 1332 syncache_unreach(&inc, &th); 1333 INP_INFO_WUNLOCK(&tcbinfo); 1334 } else 1335 in6_pcbnotify(&tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1336 0, cmd, NULL, notify); 1337 } 1338 #endif /* INET6 */ 1339 1340 1341 /* 1342 * Following is where TCP initial sequence number generation occurs. 1343 * 1344 * There are two places where we must use initial sequence numbers: 1345 * 1. In SYN-ACK packets. 1346 * 2. In SYN packets. 1347 * 1348 * All ISNs for SYN-ACK packets are generated by the syncache. See 1349 * tcp_syncache.c for details. 1350 * 1351 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1352 * depends on this property. In addition, these ISNs should be 1353 * unguessable so as to prevent connection hijacking. To satisfy 1354 * the requirements of this situation, the algorithm outlined in 1355 * RFC 1948 is used, with only small modifications. 1356 * 1357 * Implementation details: 1358 * 1359 * Time is based off the system timer, and is corrected so that it 1360 * increases by one megabyte per second. This allows for proper 1361 * recycling on high speed LANs while still leaving over an hour 1362 * before rollover. 1363 * 1364 * As reading the *exact* system time is too expensive to be done 1365 * whenever setting up a TCP connection, we increment the time 1366 * offset in two ways. First, a small random positive increment 1367 * is added to isn_offset for each connection that is set up. 1368 * Second, the function tcp_isn_tick fires once per clock tick 1369 * and increments isn_offset as necessary so that sequence numbers 1370 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1371 * random positive increments serve only to ensure that the same 1372 * exact sequence number is never sent out twice (as could otherwise 1373 * happen when a port is recycled in less than the system tick 1374 * interval.) 1375 * 1376 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1377 * between seeding of isn_secret. This is normally set to zero, 1378 * as reseeding should not be necessary. 1379 * 1380 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1381 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1382 * general, this means holding an exclusive (write) lock. 1383 */ 1384 1385 #define ISN_BYTES_PER_SECOND 1048576 1386 #define ISN_STATIC_INCREMENT 4096 1387 #define ISN_RANDOM_INCREMENT (4096 - 1) 1388 1389 static u_char isn_secret[32]; 1390 static int isn_last_reseed; 1391 static u_int32_t isn_offset, isn_offset_old; 1392 static MD5_CTX isn_ctx; 1393 1394 tcp_seq 1395 tcp_new_isn(struct tcpcb *tp) 1396 { 1397 u_int32_t md5_buffer[4]; 1398 tcp_seq new_isn; 1399 1400 INP_LOCK_ASSERT(tp->t_inpcb); 1401 1402 ISN_LOCK(); 1403 /* Seed if this is the first use, reseed if requested. */ 1404 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1405 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1406 < (u_int)ticks))) { 1407 read_random(&isn_secret, sizeof(isn_secret)); 1408 isn_last_reseed = ticks; 1409 } 1410 1411 /* Compute the md5 hash and return the ISN. */ 1412 MD5Init(&isn_ctx); 1413 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1414 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1415 #ifdef INET6 1416 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1417 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1418 sizeof(struct in6_addr)); 1419 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1420 sizeof(struct in6_addr)); 1421 } else 1422 #endif 1423 { 1424 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1425 sizeof(struct in_addr)); 1426 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1427 sizeof(struct in_addr)); 1428 } 1429 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1430 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1431 new_isn = (tcp_seq) md5_buffer[0]; 1432 isn_offset += ISN_STATIC_INCREMENT + 1433 (arc4random() & ISN_RANDOM_INCREMENT); 1434 new_isn += isn_offset; 1435 ISN_UNLOCK(); 1436 return (new_isn); 1437 } 1438 1439 /* 1440 * Increment the offset to the next ISN_BYTES_PER_SECOND / hz boundary 1441 * to keep time flowing at a relatively constant rate. If the random 1442 * increments have already pushed us past the projected offset, do nothing. 1443 */ 1444 static void 1445 tcp_isn_tick(void *xtp) 1446 { 1447 u_int32_t projected_offset; 1448 1449 ISN_LOCK(); 1450 projected_offset = isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1451 1452 if (projected_offset > isn_offset) 1453 isn_offset = projected_offset; 1454 1455 isn_offset_old = isn_offset; 1456 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1457 ISN_UNLOCK(); 1458 } 1459 1460 /* 1461 * When a specific ICMP unreachable message is received and the 1462 * connection state is SYN-SENT, drop the connection. This behavior 1463 * is controlled by the icmp_may_rst sysctl. 1464 */ 1465 struct inpcb * 1466 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1467 { 1468 struct tcpcb *tp; 1469 1470 INP_INFO_WLOCK_ASSERT(&tcbinfo); 1471 INP_LOCK_ASSERT(inp); 1472 1473 if ((inp->inp_vflag & INP_TIMEWAIT) || 1474 (inp->inp_vflag & INP_DROPPED)) 1475 return (inp); 1476 1477 tp = intotcpcb(inp); 1478 if (tp->t_state != TCPS_SYN_SENT) 1479 return (inp); 1480 1481 tp = tcp_drop(tp, errno); 1482 if (tp != NULL) 1483 return (inp); 1484 else 1485 return (NULL); 1486 } 1487 1488 /* 1489 * When `need fragmentation' ICMP is received, update our idea of the MSS 1490 * based on the new value in the route. Also nudge TCP to send something, 1491 * since we know the packet we just sent was dropped. 1492 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1493 */ 1494 struct inpcb * 1495 tcp_mtudisc(struct inpcb *inp, int errno) 1496 { 1497 struct tcpcb *tp; 1498 struct socket *so = inp->inp_socket; 1499 u_int maxmtu; 1500 u_int romtu; 1501 int mss; 1502 #ifdef INET6 1503 int isipv6; 1504 #endif /* INET6 */ 1505 1506 INP_LOCK_ASSERT(inp); 1507 if ((inp->inp_vflag & INP_TIMEWAIT) || 1508 (inp->inp_vflag & INP_DROPPED)) 1509 return (inp); 1510 1511 tp = intotcpcb(inp); 1512 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1513 1514 #ifdef INET6 1515 isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1516 #endif 1517 maxmtu = tcp_hc_getmtu(&inp->inp_inc); /* IPv4 and IPv6 */ 1518 romtu = 1519 #ifdef INET6 1520 isipv6 ? tcp_maxmtu6(&inp->inp_inc) : 1521 #endif /* INET6 */ 1522 tcp_maxmtu(&inp->inp_inc); 1523 if (!maxmtu) 1524 maxmtu = romtu; 1525 else 1526 maxmtu = min(maxmtu, romtu); 1527 if (!maxmtu) { 1528 tp->t_maxopd = tp->t_maxseg = 1529 #ifdef INET6 1530 isipv6 ? tcp_v6mssdflt : 1531 #endif /* INET6 */ 1532 tcp_mssdflt; 1533 return (inp); 1534 } 1535 mss = maxmtu - 1536 #ifdef INET6 1537 (isipv6 ? sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1538 #endif /* INET6 */ 1539 sizeof(struct tcpiphdr) 1540 #ifdef INET6 1541 ) 1542 #endif /* INET6 */ 1543 ; 1544 1545 /* 1546 * XXX - The above conditional probably violates the TCP 1547 * spec. The problem is that, since we don't know the 1548 * other end's MSS, we are supposed to use a conservative 1549 * default. But, if we do that, then MTU discovery will 1550 * never actually take place, because the conservative 1551 * default is much less than the MTUs typically seen 1552 * on the Internet today. For the moment, we'll sweep 1553 * this under the carpet. 1554 * 1555 * The conservative default might not actually be a problem 1556 * if the only case this occurs is when sending an initial 1557 * SYN with options and data to a host we've never talked 1558 * to before. Then, they will reply with an MSS value which 1559 * will get recorded and the new parameters should get 1560 * recomputed. For Further Study. 1561 */ 1562 if (tp->t_maxopd <= mss) 1563 return (inp); 1564 tp->t_maxopd = mss; 1565 1566 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1567 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1568 mss -= TCPOLEN_TSTAMP_APPA; 1569 #if (MCLBYTES & (MCLBYTES - 1)) == 0 1570 if (mss > MCLBYTES) 1571 mss &= ~(MCLBYTES-1); 1572 #else 1573 if (mss > MCLBYTES) 1574 mss = mss / MCLBYTES * MCLBYTES; 1575 #endif 1576 if (so->so_snd.sb_hiwat < mss) 1577 mss = so->so_snd.sb_hiwat; 1578 1579 tp->t_maxseg = mss; 1580 1581 tcpstat.tcps_mturesent++; 1582 tp->t_rtttime = 0; 1583 tp->snd_nxt = tp->snd_una; 1584 tcp_output(tp); 1585 return (inp); 1586 } 1587 1588 /* 1589 * Look-up the routing entry to the peer of this inpcb. If no route 1590 * is found and it cannot be allocated, then return NULL. This routine 1591 * is called by TCP routines that access the rmx structure and by tcp_mss 1592 * to get the interface MTU. 1593 */ 1594 u_long 1595 tcp_maxmtu(struct in_conninfo *inc) 1596 { 1597 struct route sro; 1598 struct sockaddr_in *dst; 1599 struct ifnet *ifp; 1600 u_long maxmtu = 0; 1601 1602 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1603 1604 bzero(&sro, sizeof(sro)); 1605 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1606 dst = (struct sockaddr_in *)&sro.ro_dst; 1607 dst->sin_family = AF_INET; 1608 dst->sin_len = sizeof(*dst); 1609 dst->sin_addr = inc->inc_faddr; 1610 rtalloc_ign(&sro, RTF_CLONING); 1611 } 1612 if (sro.ro_rt != NULL) { 1613 ifp = sro.ro_rt->rt_ifp; 1614 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1615 maxmtu = ifp->if_mtu; 1616 else 1617 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1618 RTFREE(sro.ro_rt); 1619 } 1620 return (maxmtu); 1621 } 1622 1623 #ifdef INET6 1624 u_long 1625 tcp_maxmtu6(struct in_conninfo *inc) 1626 { 1627 struct route_in6 sro6; 1628 struct ifnet *ifp; 1629 u_long maxmtu = 0; 1630 1631 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1632 1633 bzero(&sro6, sizeof(sro6)); 1634 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1635 sro6.ro_dst.sin6_family = AF_INET6; 1636 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1637 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1638 rtalloc_ign((struct route *)&sro6, RTF_CLONING); 1639 } 1640 if (sro6.ro_rt != NULL) { 1641 ifp = sro6.ro_rt->rt_ifp; 1642 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1643 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1644 else 1645 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1646 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1647 RTFREE(sro6.ro_rt); 1648 } 1649 1650 return (maxmtu); 1651 } 1652 #endif /* INET6 */ 1653 1654 #ifdef IPSEC 1655 /* compute ESP/AH header size for TCP, including outer IP header. */ 1656 size_t 1657 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1658 { 1659 struct inpcb *inp; 1660 struct mbuf *m; 1661 size_t hdrsiz; 1662 struct ip *ip; 1663 #ifdef INET6 1664 struct ip6_hdr *ip6; 1665 #endif 1666 struct tcphdr *th; 1667 1668 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1669 return (0); 1670 MGETHDR(m, M_DONTWAIT, MT_DATA); 1671 if (!m) 1672 return (0); 1673 1674 #ifdef INET6 1675 if ((inp->inp_vflag & INP_IPV6) != 0) { 1676 ip6 = mtod(m, struct ip6_hdr *); 1677 th = (struct tcphdr *)(ip6 + 1); 1678 m->m_pkthdr.len = m->m_len = 1679 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1680 tcpip_fillheaders(inp, ip6, th); 1681 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1682 } else 1683 #endif /* INET6 */ 1684 { 1685 ip = mtod(m, struct ip *); 1686 th = (struct tcphdr *)(ip + 1); 1687 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1688 tcpip_fillheaders(inp, ip, th); 1689 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1690 } 1691 1692 m_free(m); 1693 return (hdrsiz); 1694 } 1695 #endif /*IPSEC*/ 1696 1697 /* 1698 * Move a TCP connection into TIME_WAIT state. 1699 * tcbinfo is locked. 1700 * inp is locked, and is unlocked before returning. 1701 */ 1702 void 1703 tcp_twstart(struct tcpcb *tp) 1704 { 1705 struct tcptw *tw; 1706 struct inpcb *inp; 1707 int tw_time, acknow; 1708 struct socket *so; 1709 1710 INP_INFO_WLOCK_ASSERT(&tcbinfo); /* tcp_timer_2msl_reset(). */ 1711 INP_LOCK_ASSERT(tp->t_inpcb); 1712 1713 tw = uma_zalloc(tcptw_zone, M_NOWAIT); 1714 if (tw == NULL) { 1715 tw = tcp_timer_2msl_tw(1); 1716 if (tw == NULL) { 1717 tp = tcp_close(tp); 1718 if (tp != NULL) 1719 INP_UNLOCK(tp->t_inpcb); 1720 return; 1721 } 1722 } 1723 inp = tp->t_inpcb; 1724 tw->tw_inpcb = inp; 1725 1726 /* 1727 * Recover last window size sent. 1728 */ 1729 tw->last_win = (tp->rcv_adv - tp->rcv_nxt) >> tp->rcv_scale; 1730 1731 /* 1732 * Set t_recent if timestamps are used on the connection. 1733 */ 1734 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 1735 (TF_REQ_TSTMP|TF_RCVD_TSTMP)) 1736 tw->t_recent = tp->ts_recent; 1737 else 1738 tw->t_recent = 0; 1739 1740 tw->snd_nxt = tp->snd_nxt; 1741 tw->rcv_nxt = tp->rcv_nxt; 1742 tw->iss = tp->iss; 1743 tw->irs = tp->irs; 1744 tw->t_starttime = tp->t_starttime; 1745 tw->tw_time = 0; 1746 1747 /* XXX 1748 * If this code will 1749 * be used for fin-wait-2 state also, then we may need 1750 * a ts_recent from the last segment. 1751 */ 1752 tw_time = 2 * tcp_msl; 1753 acknow = tp->t_flags & TF_ACKNOW; 1754 1755 /* 1756 * First, discard tcpcb state, which includes stopping its timers and 1757 * freeing it. tcp_discardcb() used to also release the inpcb, but 1758 * that work is now done in the caller. 1759 */ 1760 tcp_discardcb(tp); 1761 so = inp->inp_socket; 1762 SOCK_LOCK(so); 1763 tw->tw_cred = crhold(so->so_cred); 1764 tw->tw_so_options = so->so_options; 1765 SOCK_UNLOCK(so); 1766 if (acknow) 1767 tcp_twrespond(tw, TH_ACK); 1768 inp->inp_ppcb = tw; 1769 inp->inp_vflag |= INP_TIMEWAIT; 1770 tcp_timer_2msl_reset(tw, tw_time); 1771 1772 /* 1773 * If the inpcb owns the sole reference to the socket, then we can 1774 * detach and free the socket as it is not needed in time wait. 1775 */ 1776 if (inp->inp_vflag & INP_SOCKREF) { 1777 KASSERT(so->so_state & SS_PROTOREF, 1778 ("tcp_twstart: !SS_PROTOREF")); 1779 inp->inp_vflag &= ~INP_SOCKREF; 1780 #ifdef INET6 1781 if (inp->inp_vflag & INP_IPV6PROTO) 1782 in6_pcbdetach(inp); 1783 else 1784 #endif 1785 in_pcbdetach(inp); 1786 INP_UNLOCK(inp); 1787 ACCEPT_LOCK(); 1788 SOCK_LOCK(so); 1789 so->so_state &= ~SS_PROTOREF; 1790 sofree(so); 1791 } else 1792 INP_UNLOCK(inp); 1793 } 1794 1795 /* 1796 * The appromixate rate of ISN increase of Microsoft TCP stacks; 1797 * the actual rate is slightly higher due to the addition of 1798 * random positive increments. 1799 * 1800 * Most other new OSes use semi-randomized ISN values, so we 1801 * do not need to worry about them. 1802 */ 1803 #define MS_ISN_BYTES_PER_SECOND 250000 1804 1805 /* 1806 * Determine if the ISN we will generate has advanced beyond the last 1807 * sequence number used by the previous connection. If so, indicate 1808 * that it is safe to recycle this tw socket by returning 1. 1809 * 1810 * XXXRW: This function should assert the inpcb lock as it does multiple 1811 * non-atomic reads from the tcptw, but is currently called without it from 1812 * in_pcb.c:in_pcblookup_local(). 1813 */ 1814 int 1815 tcp_twrecycleable(struct tcptw *tw) 1816 { 1817 tcp_seq new_iss = tw->iss; 1818 tcp_seq new_irs = tw->irs; 1819 1820 new_iss += (ticks - tw->t_starttime) * (ISN_BYTES_PER_SECOND / hz); 1821 new_irs += (ticks - tw->t_starttime) * (MS_ISN_BYTES_PER_SECOND / hz); 1822 1823 if (SEQ_GT(new_iss, tw->snd_nxt) && SEQ_GT(new_irs, tw->rcv_nxt)) 1824 return (1); 1825 else 1826 return (0); 1827 } 1828 1829 void 1830 tcp_twclose(struct tcptw *tw, int reuse) 1831 { 1832 struct socket *so; 1833 struct inpcb *inp; 1834 1835 /* 1836 * At this point, we are in one of two situations: 1837 * 1838 * (1) We have no socket, just an inpcb<->twtcp pair. Release it all 1839 * after validating. 1840 * 1841 * (2) We have a socket, which we may or may now own the reference 1842 * for. If we own the reference, release all the state after 1843 * validating. If not, leave it for the socket close to clean up. 1844 */ 1845 inp = tw->tw_inpcb; 1846 KASSERT((inp->inp_vflag & INP_TIMEWAIT), ("tcp_twclose: !timewait")); 1847 KASSERT(intotw(inp) == tw, ("tcp_twclose: inp_ppcb != tw")); 1848 INP_INFO_WLOCK_ASSERT(&tcbinfo); /* tcp_timer_2msl_stop(). */ 1849 INP_LOCK_ASSERT(inp); 1850 1851 tw->tw_inpcb = NULL; 1852 tcp_timer_2msl_stop(tw); 1853 inp->inp_ppcb = NULL; 1854 in_pcbdrop(inp); 1855 1856 so = inp->inp_socket; 1857 if (so != NULL) { 1858 if (inp->inp_vflag & INP_SOCKREF) { 1859 /* 1860 * If a socket is present, and we own the only 1861 * reference, we need to tear down the socket and the 1862 * inpcb. 1863 */ 1864 inp->inp_vflag &= ~INP_SOCKREF; 1865 #ifdef INET6 1866 if (inp->inp_vflag & INP_IPV6PROTO) { 1867 in6_pcbdetach(inp); 1868 in6_pcbfree(inp); 1869 } else { 1870 in_pcbdetach(inp); 1871 in_pcbfree(inp); 1872 } 1873 #endif 1874 ACCEPT_LOCK(); 1875 SOCK_LOCK(so); 1876 KASSERT(so->so_state & SS_PROTOREF, 1877 ("tcp_twclose: INP_SOCKREF && !SS_PROTOREF")); 1878 so->so_state &= ~SS_PROTOREF; 1879 sofree(so); 1880 } else { 1881 /* 1882 * If we don't own the only reference, the socket and 1883 * inpcb need to be left around to be handled by 1884 * tcp_usr_detach() later. 1885 */ 1886 INP_UNLOCK(inp); 1887 } 1888 } else { 1889 #ifdef INET6 1890 if (inp->inp_vflag & INP_IPV6PROTO) 1891 in6_pcbfree(inp); 1892 else 1893 #endif 1894 in_pcbfree(inp); 1895 } 1896 tcpstat.tcps_closed++; 1897 crfree(tw->tw_cred); 1898 tw->tw_cred = NULL; 1899 if (reuse) 1900 return; 1901 uma_zfree(tcptw_zone, tw); 1902 } 1903 1904 int 1905 tcp_twrespond(struct tcptw *tw, int flags) 1906 { 1907 struct inpcb *inp = tw->tw_inpcb; 1908 struct tcphdr *th; 1909 struct mbuf *m; 1910 struct ip *ip = NULL; 1911 u_int8_t *optp; 1912 u_int hdrlen, optlen; 1913 int error; 1914 #ifdef INET6 1915 struct ip6_hdr *ip6 = NULL; 1916 int isipv6 = inp->inp_inc.inc_isipv6; 1917 #endif 1918 1919 INP_LOCK_ASSERT(inp); 1920 1921 m = m_gethdr(M_DONTWAIT, MT_DATA); 1922 if (m == NULL) 1923 return (ENOBUFS); 1924 m->m_data += max_linkhdr; 1925 1926 #ifdef MAC 1927 mac_create_mbuf_from_inpcb(inp, m); 1928 #endif 1929 1930 #ifdef INET6 1931 if (isipv6) { 1932 hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1933 ip6 = mtod(m, struct ip6_hdr *); 1934 th = (struct tcphdr *)(ip6 + 1); 1935 tcpip_fillheaders(inp, ip6, th); 1936 } else 1937 #endif 1938 { 1939 hdrlen = sizeof(struct tcpiphdr); 1940 ip = mtod(m, struct ip *); 1941 th = (struct tcphdr *)(ip + 1); 1942 tcpip_fillheaders(inp, ip, th); 1943 } 1944 optp = (u_int8_t *)(th + 1); 1945 1946 /* 1947 * Send a timestamp and echo-reply if both our side and our peer 1948 * have sent timestamps in our SYN's and this is not a RST. 1949 */ 1950 if (tw->t_recent && flags == TH_ACK) { 1951 u_int32_t *lp = (u_int32_t *)optp; 1952 1953 /* Form timestamp option as shown in appendix A of RFC 1323. */ 1954 *lp++ = htonl(TCPOPT_TSTAMP_HDR); 1955 *lp++ = htonl(ticks); 1956 *lp = htonl(tw->t_recent); 1957 optp += TCPOLEN_TSTAMP_APPA; 1958 } 1959 1960 optlen = optp - (u_int8_t *)(th + 1); 1961 1962 m->m_len = hdrlen + optlen; 1963 m->m_pkthdr.len = m->m_len; 1964 1965 KASSERT(max_linkhdr + m->m_len <= MHLEN, ("tcptw: mbuf too small")); 1966 1967 th->th_seq = htonl(tw->snd_nxt); 1968 th->th_ack = htonl(tw->rcv_nxt); 1969 th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; 1970 th->th_flags = flags; 1971 th->th_win = htons(tw->last_win); 1972 1973 #ifdef INET6 1974 if (isipv6) { 1975 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), 1976 sizeof(struct tcphdr) + optlen); 1977 ip6->ip6_hlim = in6_selecthlim(inp, NULL); 1978 error = ip6_output(m, inp->in6p_outputopts, NULL, 1979 (tw->tw_so_options & SO_DONTROUTE), NULL, NULL, inp); 1980 } else 1981 #endif 1982 { 1983 th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 1984 htons(sizeof(struct tcphdr) + optlen + IPPROTO_TCP)); 1985 m->m_pkthdr.csum_flags = CSUM_TCP; 1986 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 1987 ip->ip_len = m->m_pkthdr.len; 1988 if (path_mtu_discovery) 1989 ip->ip_off |= IP_DF; 1990 error = ip_output(m, inp->inp_options, NULL, 1991 ((tw->tw_so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0), 1992 NULL, inp); 1993 } 1994 if (flags & TH_ACK) 1995 tcpstat.tcps_sndacks++; 1996 else 1997 tcpstat.tcps_sndctrl++; 1998 tcpstat.tcps_sndtotal++; 1999 return (error); 2000 } 2001 2002 /* 2003 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 2004 * 2005 * This code attempts to calculate the bandwidth-delay product as a 2006 * means of determining the optimal window size to maximize bandwidth, 2007 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 2008 * routers. This code also does a fairly good job keeping RTTs in check 2009 * across slow links like modems. We implement an algorithm which is very 2010 * similar (but not meant to be) TCP/Vegas. The code operates on the 2011 * transmitter side of a TCP connection and so only effects the transmit 2012 * side of the connection. 2013 * 2014 * BACKGROUND: TCP makes no provision for the management of buffer space 2015 * at the end points or at the intermediate routers and switches. A TCP 2016 * stream, whether using NewReno or not, will eventually buffer as 2017 * many packets as it is able and the only reason this typically works is 2018 * due to the fairly small default buffers made available for a connection 2019 * (typicaly 16K or 32K). As machines use larger windows and/or window 2020 * scaling it is now fairly easy for even a single TCP connection to blow-out 2021 * all available buffer space not only on the local interface, but on 2022 * intermediate routers and switches as well. NewReno makes a misguided 2023 * attempt to 'solve' this problem by waiting for an actual failure to occur, 2024 * then backing off, then steadily increasing the window again until another 2025 * failure occurs, ad-infinitum. This results in terrible oscillation that 2026 * is only made worse as network loads increase and the idea of intentionally 2027 * blowing out network buffers is, frankly, a terrible way to manage network 2028 * resources. 2029 * 2030 * It is far better to limit the transmit window prior to the failure 2031 * condition being achieved. There are two general ways to do this: First 2032 * you can 'scan' through different transmit window sizes and locate the 2033 * point where the RTT stops increasing, indicating that you have filled the 2034 * pipe, then scan backwards until you note that RTT stops decreasing, then 2035 * repeat ad-infinitum. This method works in principle but has severe 2036 * implementation issues due to RTT variances, timer granularity, and 2037 * instability in the algorithm which can lead to many false positives and 2038 * create oscillations as well as interact badly with other TCP streams 2039 * implementing the same algorithm. 2040 * 2041 * The second method is to limit the window to the bandwidth delay product 2042 * of the link. This is the method we implement. RTT variances and our 2043 * own manipulation of the congestion window, bwnd, can potentially 2044 * destabilize the algorithm. For this reason we have to stabilize the 2045 * elements used to calculate the window. We do this by using the minimum 2046 * observed RTT, the long term average of the observed bandwidth, and 2047 * by adding two segments worth of slop. It isn't perfect but it is able 2048 * to react to changing conditions and gives us a very stable basis on 2049 * which to extend the algorithm. 2050 */ 2051 void 2052 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 2053 { 2054 u_long bw; 2055 u_long bwnd; 2056 int save_ticks; 2057 2058 INP_LOCK_ASSERT(tp->t_inpcb); 2059 2060 /* 2061 * If inflight_enable is disabled in the middle of a tcp connection, 2062 * make sure snd_bwnd is effectively disabled. 2063 */ 2064 if (tcp_inflight_enable == 0 || tp->t_rttlow < tcp_inflight_rttthresh) { 2065 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 2066 tp->snd_bandwidth = 0; 2067 return; 2068 } 2069 2070 /* 2071 * Figure out the bandwidth. Due to the tick granularity this 2072 * is a very rough number and it MUST be averaged over a fairly 2073 * long period of time. XXX we need to take into account a link 2074 * that is not using all available bandwidth, but for now our 2075 * slop will ramp us up if this case occurs and the bandwidth later 2076 * increases. 2077 * 2078 * Note: if ticks rollover 'bw' may wind up negative. We must 2079 * effectively reset t_bw_rtttime for this case. 2080 */ 2081 save_ticks = ticks; 2082 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 2083 return; 2084 2085 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 2086 (save_ticks - tp->t_bw_rtttime); 2087 tp->t_bw_rtttime = save_ticks; 2088 tp->t_bw_rtseq = ack_seq; 2089 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 2090 return; 2091 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 2092 2093 tp->snd_bandwidth = bw; 2094 2095 /* 2096 * Calculate the semi-static bandwidth delay product, plus two maximal 2097 * segments. The additional slop puts us squarely in the sweet 2098 * spot and also handles the bandwidth run-up case and stabilization. 2099 * Without the slop we could be locking ourselves into a lower 2100 * bandwidth. 2101 * 2102 * Situations Handled: 2103 * (1) Prevents over-queueing of packets on LANs, especially on 2104 * high speed LANs, allowing larger TCP buffers to be 2105 * specified, and also does a good job preventing 2106 * over-queueing of packets over choke points like modems 2107 * (at least for the transmit side). 2108 * 2109 * (2) Is able to handle changing network loads (bandwidth 2110 * drops so bwnd drops, bandwidth increases so bwnd 2111 * increases). 2112 * 2113 * (3) Theoretically should stabilize in the face of multiple 2114 * connections implementing the same algorithm (this may need 2115 * a little work). 2116 * 2117 * (4) Stability value (defaults to 20 = 2 maximal packets) can 2118 * be adjusted with a sysctl but typically only needs to be 2119 * on very slow connections. A value no smaller then 5 2120 * should be used, but only reduce this default if you have 2121 * no other choice. 2122 */ 2123 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 2124 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + tcp_inflight_stab * tp->t_maxseg / 10; 2125 #undef USERTT 2126 2127 if (tcp_inflight_debug > 0) { 2128 static int ltime; 2129 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 2130 ltime = ticks; 2131 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 2132 tp, 2133 bw, 2134 tp->t_rttbest, 2135 tp->t_srtt, 2136 bwnd 2137 ); 2138 } 2139 } 2140 if ((long)bwnd < tcp_inflight_min) 2141 bwnd = tcp_inflight_min; 2142 if (bwnd > tcp_inflight_max) 2143 bwnd = tcp_inflight_max; 2144 if ((long)bwnd < tp->t_maxseg * 2) 2145 bwnd = tp->t_maxseg * 2; 2146 tp->snd_bwnd = bwnd; 2147 } 2148 2149 #ifdef TCP_SIGNATURE 2150 /* 2151 * Callback function invoked by m_apply() to digest TCP segment data 2152 * contained within an mbuf chain. 2153 */ 2154 static int 2155 tcp_signature_apply(void *fstate, void *data, u_int len) 2156 { 2157 2158 MD5Update(fstate, (u_char *)data, len); 2159 return (0); 2160 } 2161 2162 /* 2163 * Compute TCP-MD5 hash of a TCPv4 segment. (RFC2385) 2164 * 2165 * Parameters: 2166 * m pointer to head of mbuf chain 2167 * off0 offset to TCP header within the mbuf chain 2168 * len length of TCP segment data, excluding options 2169 * optlen length of TCP segment options 2170 * buf pointer to storage for computed MD5 digest 2171 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 2172 * 2173 * We do this over ip, tcphdr, segment data, and the key in the SADB. 2174 * When called from tcp_input(), we can be sure that th_sum has been 2175 * zeroed out and verified already. 2176 * 2177 * This function is for IPv4 use only. Calling this function with an 2178 * IPv6 packet in the mbuf chain will yield undefined results. 2179 * 2180 * Return 0 if successful, otherwise return -1. 2181 * 2182 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 2183 * search with the destination IP address, and a 'magic SPI' to be 2184 * determined by the application. This is hardcoded elsewhere to 1179 2185 * right now. Another branch of this code exists which uses the SPD to 2186 * specify per-application flows but it is unstable. 2187 */ 2188 int 2189 tcp_signature_compute(struct mbuf *m, int off0, int len, int optlen, 2190 u_char *buf, u_int direction) 2191 { 2192 union sockaddr_union dst; 2193 struct ippseudo ippseudo; 2194 MD5_CTX ctx; 2195 int doff; 2196 struct ip *ip; 2197 struct ipovly *ipovly; 2198 struct secasvar *sav; 2199 struct tcphdr *th; 2200 u_short savecsum; 2201 2202 KASSERT(m != NULL, ("NULL mbuf chain")); 2203 KASSERT(buf != NULL, ("NULL signature pointer")); 2204 2205 /* Extract the destination from the IP header in the mbuf. */ 2206 ip = mtod(m, struct ip *); 2207 bzero(&dst, sizeof(union sockaddr_union)); 2208 dst.sa.sa_len = sizeof(struct sockaddr_in); 2209 dst.sa.sa_family = AF_INET; 2210 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 2211 ip->ip_src : ip->ip_dst; 2212 2213 /* Look up an SADB entry which matches the address of the peer. */ 2214 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2215 if (sav == NULL) { 2216 printf("%s: SADB lookup failed for %s\n", __func__, 2217 inet_ntoa(dst.sin.sin_addr)); 2218 return (EINVAL); 2219 } 2220 2221 MD5Init(&ctx); 2222 ipovly = (struct ipovly *)ip; 2223 th = (struct tcphdr *)((u_char *)ip + off0); 2224 doff = off0 + sizeof(struct tcphdr) + optlen; 2225 2226 /* 2227 * Step 1: Update MD5 hash with IP pseudo-header. 2228 * 2229 * XXX The ippseudo header MUST be digested in network byte order, 2230 * or else we'll fail the regression test. Assume all fields we've 2231 * been doing arithmetic on have been in host byte order. 2232 * XXX One cannot depend on ipovly->ih_len here. When called from 2233 * tcp_output(), the underlying ip_len member has not yet been set. 2234 */ 2235 ippseudo.ippseudo_src = ipovly->ih_src; 2236 ippseudo.ippseudo_dst = ipovly->ih_dst; 2237 ippseudo.ippseudo_pad = 0; 2238 ippseudo.ippseudo_p = IPPROTO_TCP; 2239 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + optlen); 2240 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2241 2242 /* 2243 * Step 2: Update MD5 hash with TCP header, excluding options. 2244 * The TCP checksum must be set to zero. 2245 */ 2246 savecsum = th->th_sum; 2247 th->th_sum = 0; 2248 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2249 th->th_sum = savecsum; 2250 2251 /* 2252 * Step 3: Update MD5 hash with TCP segment data. 2253 * Use m_apply() to avoid an early m_pullup(). 2254 */ 2255 if (len > 0) 2256 m_apply(m, doff, len, tcp_signature_apply, &ctx); 2257 2258 /* 2259 * Step 4: Update MD5 hash with shared secret. 2260 */ 2261 MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); 2262 MD5Final(buf, &ctx); 2263 2264 key_sa_recordxfer(sav, m); 2265 KEY_FREESAV(&sav); 2266 return (0); 2267 } 2268 #endif /* TCP_SIGNATURE */ 2269 2270 static int 2271 sysctl_drop(SYSCTL_HANDLER_ARGS) 2272 { 2273 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 2274 struct sockaddr_storage addrs[2]; 2275 struct inpcb *inp; 2276 struct tcpcb *tp; 2277 struct tcptw *tw; 2278 struct sockaddr_in *fin, *lin; 2279 #ifdef INET6 2280 struct sockaddr_in6 *fin6, *lin6; 2281 struct in6_addr f6, l6; 2282 #endif 2283 int error; 2284 2285 inp = NULL; 2286 fin = lin = NULL; 2287 #ifdef INET6 2288 fin6 = lin6 = NULL; 2289 #endif 2290 error = 0; 2291 2292 if (req->oldptr != NULL || req->oldlen != 0) 2293 return (EINVAL); 2294 if (req->newptr == NULL) 2295 return (EPERM); 2296 if (req->newlen < sizeof(addrs)) 2297 return (ENOMEM); 2298 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2299 if (error) 2300 return (error); 2301 2302 switch (addrs[0].ss_family) { 2303 #ifdef INET6 2304 case AF_INET6: 2305 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2306 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2307 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2308 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2309 return (EINVAL); 2310 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2311 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2312 return (EINVAL); 2313 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2314 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2315 fin = (struct sockaddr_in *)&addrs[0]; 2316 lin = (struct sockaddr_in *)&addrs[1]; 2317 break; 2318 } 2319 error = sa6_embedscope(fin6, ip6_use_defzone); 2320 if (error) 2321 return (error); 2322 error = sa6_embedscope(lin6, ip6_use_defzone); 2323 if (error) 2324 return (error); 2325 break; 2326 #endif 2327 case AF_INET: 2328 fin = (struct sockaddr_in *)&addrs[0]; 2329 lin = (struct sockaddr_in *)&addrs[1]; 2330 if (fin->sin_len != sizeof(struct sockaddr_in) || 2331 lin->sin_len != sizeof(struct sockaddr_in)) 2332 return (EINVAL); 2333 break; 2334 default: 2335 return (EINVAL); 2336 } 2337 INP_INFO_WLOCK(&tcbinfo); 2338 switch (addrs[0].ss_family) { 2339 #ifdef INET6 2340 case AF_INET6: 2341 inp = in6_pcblookup_hash(&tcbinfo, &f6, fin6->sin6_port, 2342 &l6, lin6->sin6_port, 0, NULL); 2343 break; 2344 #endif 2345 case AF_INET: 2346 inp = in_pcblookup_hash(&tcbinfo, fin->sin_addr, fin->sin_port, 2347 lin->sin_addr, lin->sin_port, 0, NULL); 2348 break; 2349 } 2350 if (inp != NULL) { 2351 INP_LOCK(inp); 2352 if (inp->inp_vflag & INP_TIMEWAIT) { 2353 /* 2354 * XXXRW: There currently exists a state where an 2355 * inpcb is present, but its timewait state has been 2356 * discarded. For now, don't allow dropping of this 2357 * type of inpcb. 2358 */ 2359 tw = intotw(inp); 2360 if (tw != NULL) 2361 tcp_twclose(tw, 0); 2362 } else if (!(inp->inp_vflag & INP_DROPPED) && 2363 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2364 tp = intotcpcb(inp); 2365 tcp_drop(tp, ECONNABORTED); 2366 } 2367 INP_UNLOCK(inp); 2368 } else 2369 error = ESRCH; 2370 INP_INFO_WUNLOCK(&tcbinfo); 2371 return (error); 2372 } 2373 2374 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2375 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2376 0, sysctl_drop, "", "Drop TCP connection"); 2377