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 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_compat.h" 36 #include "opt_inet.h" 37 #include "opt_inet6.h" 38 #include "opt_ipsec.h" 39 #include "opt_tcpdebug.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/malloc.h> 47 #include <sys/mbuf.h> 48 #ifdef INET6 49 #include <sys/domain.h> 50 #endif 51 #include <sys/priv.h> 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 #include <sys/vimage.h> 58 59 #include <vm/uma.h> 60 61 #include <net/route.h> 62 #include <net/if.h> 63 64 #include <netinet/in.h> 65 #include <netinet/in_systm.h> 66 #include <netinet/ip.h> 67 #ifdef INET6 68 #include <netinet/ip6.h> 69 #endif 70 #include <netinet/in_pcb.h> 71 #ifdef INET6 72 #include <netinet6/in6_pcb.h> 73 #endif 74 #include <netinet/in_var.h> 75 #include <netinet/ip_var.h> 76 #ifdef INET6 77 #include <netinet6/ip6_var.h> 78 #include <netinet6/scope6_var.h> 79 #include <netinet6/nd6.h> 80 #endif 81 #include <netinet/ip_icmp.h> 82 #include <netinet/tcp.h> 83 #include <netinet/tcp_fsm.h> 84 #include <netinet/tcp_seq.h> 85 #include <netinet/tcp_timer.h> 86 #include <netinet/tcp_var.h> 87 #include <netinet/tcp_syncache.h> 88 #include <netinet/tcp_offload.h> 89 #ifdef INET6 90 #include <netinet6/tcp6_var.h> 91 #endif 92 #include <netinet/tcpip.h> 93 #ifdef TCPDEBUG 94 #include <netinet/tcp_debug.h> 95 #endif 96 #include <netinet/vinet.h> 97 #include <netinet6/ip6protosw.h> 98 #include <netinet6/vinet6.h> 99 100 #ifdef IPSEC 101 #include <netipsec/ipsec.h> 102 #include <netipsec/xform.h> 103 #ifdef INET6 104 #include <netipsec/ipsec6.h> 105 #endif 106 #include <netipsec/key.h> 107 #include <sys/syslog.h> 108 #endif /*IPSEC*/ 109 110 #include <machine/in_cksum.h> 111 #include <sys/md5.h> 112 113 #include <security/mac/mac_framework.h> 114 115 #ifdef VIMAGE_GLOBALS 116 int tcp_mssdflt; 117 #ifdef INET6 118 int tcp_v6mssdflt; 119 #endif 120 int tcp_minmss; 121 int tcp_do_rfc1323; 122 static int icmp_may_rst; 123 static int tcp_isn_reseed_interval; 124 static int tcp_inflight_enable; 125 static int tcp_inflight_rttthresh; 126 static int tcp_inflight_min; 127 static int tcp_inflight_max; 128 static int tcp_inflight_stab; 129 #endif 130 131 static int 132 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS) 133 { 134 INIT_VNET_INET(curvnet); 135 int error, new; 136 137 new = V_tcp_mssdflt; 138 error = sysctl_handle_int(oidp, &new, 0, req); 139 if (error == 0 && req->newptr) { 140 if (new < TCP_MINMSS) 141 error = EINVAL; 142 else 143 V_tcp_mssdflt = new; 144 } 145 return (error); 146 } 147 148 SYSCTL_V_PROC(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, 149 CTLTYPE_INT|CTLFLAG_RW, tcp_mssdflt, 0, 150 &sysctl_net_inet_tcp_mss_check, "I", 151 "Default TCP Maximum Segment Size"); 152 153 #ifdef INET6 154 static int 155 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS) 156 { 157 INIT_VNET_INET(curvnet); 158 int error, new; 159 160 new = V_tcp_v6mssdflt; 161 error = sysctl_handle_int(oidp, &new, 0, req); 162 if (error == 0 && req->newptr) { 163 if (new < TCP_MINMSS) 164 error = EINVAL; 165 else 166 V_tcp_v6mssdflt = new; 167 } 168 return (error); 169 } 170 171 SYSCTL_V_PROC(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 172 CTLTYPE_INT|CTLFLAG_RW, tcp_v6mssdflt, 0, 173 &sysctl_net_inet_tcp_mss_v6_check, "I", 174 "Default TCP Maximum Segment Size for IPv6"); 175 #endif 176 177 /* 178 * Minimum MSS we accept and use. This prevents DoS attacks where 179 * we are forced to a ridiculous low MSS like 20 and send hundreds 180 * of packets instead of one. The effect scales with the available 181 * bandwidth and quickly saturates the CPU and network interface 182 * with packet generation and sending. Set to zero to disable MINMSS 183 * checking. This setting prevents us from sending too small packets. 184 */ 185 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, minmss, 186 CTLFLAG_RW, tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 187 188 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, 189 CTLFLAG_RW, tcp_do_rfc1323, 0, 190 "Enable rfc1323 (high performance TCP) extensions"); 191 192 static int tcp_log_debug = 0; 193 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW, 194 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments"); 195 196 static int tcp_tcbhashsize = 0; 197 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 198 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 199 200 static int do_tcpdrain = 1; 201 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 202 "Enable tcp_drain routine for extra help when low on mbufs"); 203 204 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, pcbcount, 205 CTLFLAG_RD, tcbinfo.ipi_count, 0, "Number of active PCBs"); 206 207 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, icmp_may_rst, 208 CTLFLAG_RW, icmp_may_rst, 0, 209 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 210 211 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, isn_reseed_interval, 212 CTLFLAG_RW, tcp_isn_reseed_interval, 0, 213 "Seconds between reseeding of ISN secret"); 214 215 /* 216 * TCP bandwidth limiting sysctls. Note that the default lower bound of 217 * 1024 exists only for debugging. A good production default would be 218 * something like 6100. 219 */ 220 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0, 221 "TCP inflight data limiting"); 222 223 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, enable, 224 CTLFLAG_RW, tcp_inflight_enable, 0, 225 "Enable automatic TCP inflight data limiting"); 226 227 static int tcp_inflight_debug = 0; 228 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW, 229 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 230 231 SYSCTL_V_PROC(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, rttthresh, 232 CTLTYPE_INT|CTLFLAG_RW, tcp_inflight_rttthresh, 0, sysctl_msec_to_ticks, 233 "I", "RTT threshold below which inflight will deactivate itself"); 234 235 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, min, 236 CTLFLAG_RW, tcp_inflight_min, 0, "Lower-bound for TCP inflight window"); 237 238 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, max, 239 CTLFLAG_RW, tcp_inflight_max, 0, "Upper-bound for TCP inflight window"); 240 241 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, stab, 242 CTLFLAG_RW, tcp_inflight_stab, 0, 243 "Inflight Algorithm Stabilization 20 = 2 packets"); 244 245 #ifdef VIMAGE_GLOBALS 246 uma_zone_t sack_hole_zone; 247 #endif 248 249 static struct inpcb *tcp_notify(struct inpcb *, int); 250 static void tcp_isn_tick(void *); 251 252 /* 253 * Target size of TCP PCB hash tables. Must be a power of two. 254 * 255 * Note that this can be overridden by the kernel environment 256 * variable net.inet.tcp.tcbhashsize 257 */ 258 #ifndef TCBHASHSIZE 259 #define TCBHASHSIZE 512 260 #endif 261 262 /* 263 * XXX 264 * Callouts should be moved into struct tcp directly. They are currently 265 * separate because the tcpcb structure is exported to userland for sysctl 266 * parsing purposes, which do not know about callouts. 267 */ 268 struct tcpcb_mem { 269 struct tcpcb tcb; 270 struct tcp_timer tt; 271 }; 272 273 #ifdef VIMAGE_GLOBALS 274 static uma_zone_t tcpcb_zone; 275 #endif 276 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers"); 277 struct callout isn_callout; 278 static struct mtx isn_mtx; 279 280 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 281 #define ISN_LOCK() mtx_lock(&isn_mtx) 282 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 283 284 /* 285 * TCP initialization. 286 */ 287 static void 288 tcp_zone_change(void *tag) 289 { 290 INIT_VNET_INET(curvnet); 291 292 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 293 uma_zone_set_max(V_tcpcb_zone, maxsockets); 294 tcp_tw_zone_change(); 295 } 296 297 static int 298 tcp_inpcb_init(void *mem, int size, int flags) 299 { 300 struct inpcb *inp = mem; 301 302 INP_LOCK_INIT(inp, "inp", "tcpinp"); 303 return (0); 304 } 305 306 void 307 tcp_init(void) 308 { 309 INIT_VNET_INET(curvnet); 310 int hashsize; 311 312 V_blackhole = 0; 313 V_tcp_delack_enabled = 1; 314 V_drop_synfin = 0; 315 V_tcp_do_rfc3042 = 1; 316 V_tcp_do_rfc3390 = 1; 317 V_tcp_do_ecn = 0; 318 V_tcp_ecn_maxretries = 1; 319 V_tcp_insecure_rst = 0; 320 V_tcp_do_autorcvbuf = 1; 321 V_tcp_autorcvbuf_inc = 16*1024; 322 V_tcp_autorcvbuf_max = 256*1024; 323 V_tcp_do_rfc3465 = 1; 324 V_tcp_abc_l_var = 2; 325 326 V_tcp_mssdflt = TCP_MSS; 327 #ifdef INET6 328 V_tcp_v6mssdflt = TCP6_MSS; 329 #endif 330 V_tcp_minmss = TCP_MINMSS; 331 V_tcp_do_rfc1323 = 1; 332 V_icmp_may_rst = 1; 333 V_tcp_isn_reseed_interval = 0; 334 V_tcp_inflight_enable = 1; 335 V_tcp_inflight_min = 6144; 336 V_tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 337 V_tcp_inflight_stab = 20; 338 339 V_path_mtu_discovery = 1; 340 V_ss_fltsz = 1; 341 V_ss_fltsz_local = 4; 342 V_tcp_do_newreno = 1; 343 V_tcp_do_tso = 1; 344 V_tcp_do_autosndbuf = 1; 345 V_tcp_autosndbuf_inc = 8*1024; 346 V_tcp_autosndbuf_max = 256*1024; 347 348 V_nolocaltimewait = 0; 349 350 V_tcp_do_sack = 1; 351 V_tcp_sack_maxholes = 128; 352 V_tcp_sack_globalmaxholes = 65536; 353 V_tcp_sack_globalholes = 0; 354 355 V_tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 356 357 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack); 358 359 INP_INFO_LOCK_INIT(&V_tcbinfo, "tcp"); 360 LIST_INIT(&V_tcb); 361 #ifdef VIMAGE 362 V_tcbinfo.ipi_vnet = curvnet; 363 #endif 364 V_tcbinfo.ipi_listhead = &V_tcb; 365 hashsize = TCBHASHSIZE; 366 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 367 if (!powerof2(hashsize)) { 368 printf("WARNING: TCB hash size not a power of 2\n"); 369 hashsize = 512; /* safe default */ 370 } 371 V_tcbinfo.ipi_hashbase = hashinit(hashsize, M_PCB, 372 &V_tcbinfo.ipi_hashmask); 373 V_tcbinfo.ipi_porthashbase = hashinit(hashsize, M_PCB, 374 &V_tcbinfo.ipi_porthashmask); 375 V_tcbinfo.ipi_zone = uma_zcreate("tcp_inpcb", sizeof(struct inpcb), 376 NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 377 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 378 /* 379 * These have to be type stable for the benefit of the timers. 380 */ 381 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 382 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 383 uma_zone_set_max(V_tcpcb_zone, maxsockets); 384 tcp_tw_init(); 385 syncache_init(); 386 tcp_hc_init(); 387 tcp_reass_init(); 388 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 389 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 390 391 /* Skip initialization of globals for non-default instances. */ 392 if (!IS_DEFAULT_VNET(curvnet)) 393 return; 394 395 /* XXX virtualize those bellow? */ 396 tcp_delacktime = TCPTV_DELACK; 397 tcp_keepinit = TCPTV_KEEP_INIT; 398 tcp_keepidle = TCPTV_KEEP_IDLE; 399 tcp_keepintvl = TCPTV_KEEPINTVL; 400 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 401 tcp_msl = TCPTV_MSL; 402 tcp_rexmit_min = TCPTV_MIN; 403 if (tcp_rexmit_min < 1) 404 tcp_rexmit_min = 1; 405 tcp_rexmit_slop = TCPTV_CPU_VAR; 406 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 407 tcp_tcbhashsize = hashsize; 408 409 #ifdef INET6 410 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 411 #else /* INET6 */ 412 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 413 #endif /* INET6 */ 414 if (max_protohdr < TCP_MINPROTOHDR) 415 max_protohdr = TCP_MINPROTOHDR; 416 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 417 panic("tcp_init"); 418 #undef TCP_MINPROTOHDR 419 420 ISN_LOCK_INIT(); 421 callout_init(&isn_callout, CALLOUT_MPSAFE); 422 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 423 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 424 SHUTDOWN_PRI_DEFAULT); 425 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 426 EVENTHANDLER_PRI_ANY); 427 } 428 429 void 430 tcp_fini(void *xtp) 431 { 432 433 callout_stop(&isn_callout); 434 } 435 436 /* 437 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 438 * tcp_template used to store this data in mbufs, but we now recopy it out 439 * of the tcpcb each time to conserve mbufs. 440 */ 441 void 442 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 443 { 444 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 445 446 INP_WLOCK_ASSERT(inp); 447 448 #ifdef INET6 449 if ((inp->inp_vflag & INP_IPV6) != 0) { 450 struct ip6_hdr *ip6; 451 452 ip6 = (struct ip6_hdr *)ip_ptr; 453 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 454 (inp->inp_flow & IPV6_FLOWINFO_MASK); 455 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 456 (IPV6_VERSION & IPV6_VERSION_MASK); 457 ip6->ip6_nxt = IPPROTO_TCP; 458 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 459 ip6->ip6_src = inp->in6p_laddr; 460 ip6->ip6_dst = inp->in6p_faddr; 461 } else 462 #endif 463 { 464 struct ip *ip; 465 466 ip = (struct ip *)ip_ptr; 467 ip->ip_v = IPVERSION; 468 ip->ip_hl = 5; 469 ip->ip_tos = inp->inp_ip_tos; 470 ip->ip_len = 0; 471 ip->ip_id = 0; 472 ip->ip_off = 0; 473 ip->ip_ttl = inp->inp_ip_ttl; 474 ip->ip_sum = 0; 475 ip->ip_p = IPPROTO_TCP; 476 ip->ip_src = inp->inp_laddr; 477 ip->ip_dst = inp->inp_faddr; 478 } 479 th->th_sport = inp->inp_lport; 480 th->th_dport = inp->inp_fport; 481 th->th_seq = 0; 482 th->th_ack = 0; 483 th->th_x2 = 0; 484 th->th_off = 5; 485 th->th_flags = 0; 486 th->th_win = 0; 487 th->th_urp = 0; 488 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 489 } 490 491 /* 492 * Create template to be used to send tcp packets on a connection. 493 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 494 * use for this function is in keepalives, which use tcp_respond. 495 */ 496 struct tcptemp * 497 tcpip_maketemplate(struct inpcb *inp) 498 { 499 struct tcptemp *t; 500 501 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT); 502 if (t == NULL) 503 return (NULL); 504 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t); 505 return (t); 506 } 507 508 /* 509 * Send a single message to the TCP at address specified by 510 * the given TCP/IP header. If m == NULL, then we make a copy 511 * of the tcpiphdr at ti and send directly to the addressed host. 512 * This is used to force keep alive messages out using the TCP 513 * template for a connection. If flags are given then we send 514 * a message back to the TCP which originated the * segment ti, 515 * and discard the mbuf containing it and any other attached mbufs. 516 * 517 * In any case the ack and sequence number of the transmitted 518 * segment are as specified by the parameters. 519 * 520 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 521 */ 522 void 523 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 524 tcp_seq ack, tcp_seq seq, int flags) 525 { 526 INIT_VNET_INET(curvnet); 527 int tlen; 528 int win = 0; 529 struct ip *ip; 530 struct tcphdr *nth; 531 #ifdef INET6 532 struct ip6_hdr *ip6; 533 int isipv6; 534 #endif /* INET6 */ 535 int ipflags = 0; 536 struct inpcb *inp; 537 538 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 539 540 #ifdef INET6 541 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 542 ip6 = ipgen; 543 #endif /* INET6 */ 544 ip = ipgen; 545 546 if (tp != NULL) { 547 inp = tp->t_inpcb; 548 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 549 INP_WLOCK_ASSERT(inp); 550 } else 551 inp = NULL; 552 553 if (tp != NULL) { 554 if (!(flags & TH_RST)) { 555 win = sbspace(&inp->inp_socket->so_rcv); 556 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 557 win = (long)TCP_MAXWIN << tp->rcv_scale; 558 } 559 } 560 if (m == NULL) { 561 m = m_gethdr(M_DONTWAIT, MT_DATA); 562 if (m == NULL) 563 return; 564 tlen = 0; 565 m->m_data += max_linkhdr; 566 #ifdef INET6 567 if (isipv6) { 568 bcopy((caddr_t)ip6, mtod(m, caddr_t), 569 sizeof(struct ip6_hdr)); 570 ip6 = mtod(m, struct ip6_hdr *); 571 nth = (struct tcphdr *)(ip6 + 1); 572 } else 573 #endif /* INET6 */ 574 { 575 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 576 ip = mtod(m, struct ip *); 577 nth = (struct tcphdr *)(ip + 1); 578 } 579 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 580 flags = TH_ACK; 581 } else { 582 /* 583 * reuse the mbuf. 584 * XXX MRT We inherrit the FIB, which is lucky. 585 */ 586 m_freem(m->m_next); 587 m->m_next = NULL; 588 m->m_data = (caddr_t)ipgen; 589 /* m_len is set later */ 590 tlen = 0; 591 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 592 #ifdef INET6 593 if (isipv6) { 594 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 595 nth = (struct tcphdr *)(ip6 + 1); 596 } else 597 #endif /* INET6 */ 598 { 599 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t); 600 nth = (struct tcphdr *)(ip + 1); 601 } 602 if (th != nth) { 603 /* 604 * this is usually a case when an extension header 605 * exists between the IPv6 header and the 606 * TCP header. 607 */ 608 nth->th_sport = th->th_sport; 609 nth->th_dport = th->th_dport; 610 } 611 xchg(nth->th_dport, nth->th_sport, uint16_t); 612 #undef xchg 613 } 614 #ifdef INET6 615 if (isipv6) { 616 ip6->ip6_flow = 0; 617 ip6->ip6_vfc = IPV6_VERSION; 618 ip6->ip6_nxt = IPPROTO_TCP; 619 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 620 tlen)); 621 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 622 } else 623 #endif 624 { 625 tlen += sizeof (struct tcpiphdr); 626 ip->ip_len = tlen; 627 ip->ip_ttl = V_ip_defttl; 628 if (V_path_mtu_discovery) 629 ip->ip_off |= IP_DF; 630 } 631 m->m_len = tlen; 632 m->m_pkthdr.len = tlen; 633 m->m_pkthdr.rcvif = NULL; 634 #ifdef MAC 635 if (inp != NULL) { 636 /* 637 * Packet is associated with a socket, so allow the 638 * label of the response to reflect the socket label. 639 */ 640 INP_WLOCK_ASSERT(inp); 641 mac_inpcb_create_mbuf(inp, m); 642 } else { 643 /* 644 * Packet is not associated with a socket, so possibly 645 * update the label in place. 646 */ 647 mac_netinet_tcp_reply(m); 648 } 649 #endif 650 nth->th_seq = htonl(seq); 651 nth->th_ack = htonl(ack); 652 nth->th_x2 = 0; 653 nth->th_off = sizeof (struct tcphdr) >> 2; 654 nth->th_flags = flags; 655 if (tp != NULL) 656 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 657 else 658 nth->th_win = htons((u_short)win); 659 nth->th_urp = 0; 660 #ifdef INET6 661 if (isipv6) { 662 nth->th_sum = 0; 663 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 664 sizeof(struct ip6_hdr), 665 tlen - sizeof(struct ip6_hdr)); 666 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 667 NULL, NULL); 668 } else 669 #endif /* INET6 */ 670 { 671 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 672 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 673 m->m_pkthdr.csum_flags = CSUM_TCP; 674 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 675 } 676 #ifdef TCPDEBUG 677 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 678 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 679 #endif 680 #ifdef INET6 681 if (isipv6) 682 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 683 else 684 #endif /* INET6 */ 685 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 686 } 687 688 /* 689 * Create a new TCP control block, making an 690 * empty reassembly queue and hooking it to the argument 691 * protocol control block. The `inp' parameter must have 692 * come from the zone allocator set up in tcp_init(). 693 */ 694 struct tcpcb * 695 tcp_newtcpcb(struct inpcb *inp) 696 { 697 INIT_VNET_INET(inp->inp_vnet); 698 struct tcpcb_mem *tm; 699 struct tcpcb *tp; 700 #ifdef INET6 701 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 702 #endif /* INET6 */ 703 704 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO); 705 if (tm == NULL) 706 return (NULL); 707 tp = &tm->tcb; 708 #ifdef VIMAGE 709 tp->t_vnet = inp->inp_vnet; 710 #endif 711 tp->t_timers = &tm->tt; 712 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 713 tp->t_maxseg = tp->t_maxopd = 714 #ifdef INET6 715 isipv6 ? V_tcp_v6mssdflt : 716 #endif /* INET6 */ 717 V_tcp_mssdflt; 718 719 /* Set up our timeouts. */ 720 callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE); 721 callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE); 722 callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE); 723 callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE); 724 callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE); 725 726 if (V_tcp_do_rfc1323) 727 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 728 if (V_tcp_do_sack) 729 tp->t_flags |= TF_SACK_PERMIT; 730 TAILQ_INIT(&tp->snd_holes); 731 tp->t_inpcb = inp; /* XXX */ 732 /* 733 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 734 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 735 * reasonable initial retransmit time. 736 */ 737 tp->t_srtt = TCPTV_SRTTBASE; 738 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 739 tp->t_rttmin = tcp_rexmit_min; 740 tp->t_rxtcur = TCPTV_RTOBASE; 741 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 742 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 743 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 744 tp->t_rcvtime = ticks; 745 tp->t_bw_rtttime = ticks; 746 /* 747 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 748 * because the socket may be bound to an IPv6 wildcard address, 749 * which may match an IPv4-mapped IPv6 address. 750 */ 751 inp->inp_ip_ttl = V_ip_defttl; 752 inp->inp_ppcb = tp; 753 return (tp); /* XXX */ 754 } 755 756 /* 757 * Drop a TCP connection, reporting 758 * the specified error. If connection is synchronized, 759 * then send a RST to peer. 760 */ 761 struct tcpcb * 762 tcp_drop(struct tcpcb *tp, int errno) 763 { 764 INIT_VNET_INET(tp->t_inpcb->inp_vnet); 765 struct socket *so = tp->t_inpcb->inp_socket; 766 767 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 768 INP_WLOCK_ASSERT(tp->t_inpcb); 769 770 if (TCPS_HAVERCVDSYN(tp->t_state)) { 771 tp->t_state = TCPS_CLOSED; 772 (void) tcp_output_reset(tp); 773 TCPSTAT_INC(tcps_drops); 774 } else 775 TCPSTAT_INC(tcps_conndrops); 776 if (errno == ETIMEDOUT && tp->t_softerror) 777 errno = tp->t_softerror; 778 so->so_error = errno; 779 return (tcp_close(tp)); 780 } 781 782 void 783 tcp_discardcb(struct tcpcb *tp) 784 { 785 INIT_VNET_INET(tp->t_vnet); 786 struct tseg_qent *q; 787 struct inpcb *inp = tp->t_inpcb; 788 struct socket *so = inp->inp_socket; 789 #ifdef INET6 790 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 791 #endif /* INET6 */ 792 793 INP_WLOCK_ASSERT(inp); 794 795 /* 796 * Make sure that all of our timers are stopped before we 797 * delete the PCB. 798 */ 799 callout_stop(&tp->t_timers->tt_rexmt); 800 callout_stop(&tp->t_timers->tt_persist); 801 callout_stop(&tp->t_timers->tt_keep); 802 callout_stop(&tp->t_timers->tt_2msl); 803 callout_stop(&tp->t_timers->tt_delack); 804 805 /* 806 * If we got enough samples through the srtt filter, 807 * save the rtt and rttvar in the routing entry. 808 * 'Enough' is arbitrarily defined as 4 rtt samples. 809 * 4 samples is enough for the srtt filter to converge 810 * to within enough % of the correct value; fewer samples 811 * and we could save a bogus rtt. The danger is not high 812 * as tcp quickly recovers from everything. 813 * XXX: Works very well but needs some more statistics! 814 */ 815 if (tp->t_rttupdated >= 4) { 816 struct hc_metrics_lite metrics; 817 u_long ssthresh; 818 819 bzero(&metrics, sizeof(metrics)); 820 /* 821 * Update the ssthresh always when the conditions below 822 * are satisfied. This gives us better new start value 823 * for the congestion avoidance for new connections. 824 * ssthresh is only set if packet loss occured on a session. 825 * 826 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 827 * being torn down. Ideally this code would not use 'so'. 828 */ 829 ssthresh = tp->snd_ssthresh; 830 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 831 /* 832 * convert the limit from user data bytes to 833 * packets then to packet data bytes. 834 */ 835 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 836 if (ssthresh < 2) 837 ssthresh = 2; 838 ssthresh *= (u_long)(tp->t_maxseg + 839 #ifdef INET6 840 (isipv6 ? sizeof (struct ip6_hdr) + 841 sizeof (struct tcphdr) : 842 #endif 843 sizeof (struct tcpiphdr) 844 #ifdef INET6 845 ) 846 #endif 847 ); 848 } else 849 ssthresh = 0; 850 metrics.rmx_ssthresh = ssthresh; 851 852 metrics.rmx_rtt = tp->t_srtt; 853 metrics.rmx_rttvar = tp->t_rttvar; 854 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 855 metrics.rmx_bandwidth = tp->snd_bandwidth; 856 metrics.rmx_cwnd = tp->snd_cwnd; 857 metrics.rmx_sendpipe = 0; 858 metrics.rmx_recvpipe = 0; 859 860 tcp_hc_update(&inp->inp_inc, &metrics); 861 } 862 863 /* free the reassembly queue, if any */ 864 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) { 865 LIST_REMOVE(q, tqe_q); 866 m_freem(q->tqe_m); 867 uma_zfree(V_tcp_reass_zone, q); 868 tp->t_segqlen--; 869 V_tcp_reass_qsize--; 870 } 871 /* Disconnect offload device, if any. */ 872 tcp_offload_detach(tp); 873 874 tcp_free_sackholes(tp); 875 inp->inp_ppcb = NULL; 876 tp->t_inpcb = NULL; 877 uma_zfree(V_tcpcb_zone, tp); 878 } 879 880 /* 881 * Attempt to close a TCP control block, marking it as dropped, and freeing 882 * the socket if we hold the only reference. 883 */ 884 struct tcpcb * 885 tcp_close(struct tcpcb *tp) 886 { 887 INIT_VNET_INET(tp->t_inpcb->inp_vnet); 888 struct inpcb *inp = tp->t_inpcb; 889 struct socket *so; 890 891 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 892 INP_WLOCK_ASSERT(inp); 893 894 /* Notify any offload devices of listener close */ 895 if (tp->t_state == TCPS_LISTEN) 896 tcp_offload_listen_close(tp); 897 in_pcbdrop(inp); 898 TCPSTAT_INC(tcps_closed); 899 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 900 so = inp->inp_socket; 901 soisdisconnected(so); 902 if (inp->inp_flags & INP_SOCKREF) { 903 KASSERT(so->so_state & SS_PROTOREF, 904 ("tcp_close: !SS_PROTOREF")); 905 inp->inp_flags &= ~INP_SOCKREF; 906 INP_WUNLOCK(inp); 907 ACCEPT_LOCK(); 908 SOCK_LOCK(so); 909 so->so_state &= ~SS_PROTOREF; 910 sofree(so); 911 return (NULL); 912 } 913 return (tp); 914 } 915 916 void 917 tcp_drain(void) 918 { 919 VNET_ITERATOR_DECL(vnet_iter); 920 921 if (!do_tcpdrain) 922 return; 923 924 VNET_LIST_RLOCK(); 925 VNET_FOREACH(vnet_iter) { 926 CURVNET_SET(vnet_iter); 927 INIT_VNET_INET(vnet_iter); 928 struct inpcb *inpb; 929 struct tcpcb *tcpb; 930 struct tseg_qent *te; 931 932 /* 933 * Walk the tcpbs, if existing, and flush the reassembly queue, 934 * if there is one... 935 * XXX: The "Net/3" implementation doesn't imply that the TCP 936 * reassembly queue should be flushed, but in a situation 937 * where we're really low on mbufs, this is potentially 938 * usefull. 939 */ 940 INP_INFO_RLOCK(&V_tcbinfo); 941 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) { 942 if (inpb->inp_flags & INP_TIMEWAIT) 943 continue; 944 INP_WLOCK(inpb); 945 if ((tcpb = intotcpcb(inpb)) != NULL) { 946 while ((te = LIST_FIRST(&tcpb->t_segq)) 947 != NULL) { 948 LIST_REMOVE(te, tqe_q); 949 m_freem(te->tqe_m); 950 uma_zfree(V_tcp_reass_zone, te); 951 tcpb->t_segqlen--; 952 V_tcp_reass_qsize--; 953 } 954 tcp_clean_sackreport(tcpb); 955 } 956 INP_WUNLOCK(inpb); 957 } 958 INP_INFO_RUNLOCK(&V_tcbinfo); 959 CURVNET_RESTORE(); 960 } 961 VNET_LIST_RUNLOCK(); 962 } 963 964 /* 965 * Notify a tcp user of an asynchronous error; 966 * store error as soft error, but wake up user 967 * (for now, won't do anything until can select for soft error). 968 * 969 * Do not wake up user since there currently is no mechanism for 970 * reporting soft errors (yet - a kqueue filter may be added). 971 */ 972 static struct inpcb * 973 tcp_notify(struct inpcb *inp, int error) 974 { 975 struct tcpcb *tp; 976 #ifdef INVARIANTS 977 INIT_VNET_INET(inp->inp_vnet); /* V_tcbinfo WLOCK ASSERT */ 978 #endif 979 980 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 981 INP_WLOCK_ASSERT(inp); 982 983 if ((inp->inp_flags & INP_TIMEWAIT) || 984 (inp->inp_flags & INP_DROPPED)) 985 return (inp); 986 987 tp = intotcpcb(inp); 988 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 989 990 /* 991 * Ignore some errors if we are hooked up. 992 * If connection hasn't completed, has retransmitted several times, 993 * and receives a second error, give up now. This is better 994 * than waiting a long time to establish a connection that 995 * can never complete. 996 */ 997 if (tp->t_state == TCPS_ESTABLISHED && 998 (error == EHOSTUNREACH || error == ENETUNREACH || 999 error == EHOSTDOWN)) { 1000 return (inp); 1001 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1002 tp->t_softerror) { 1003 tp = tcp_drop(tp, error); 1004 if (tp != NULL) 1005 return (inp); 1006 else 1007 return (NULL); 1008 } else { 1009 tp->t_softerror = error; 1010 return (inp); 1011 } 1012 #if 0 1013 wakeup( &so->so_timeo); 1014 sorwakeup(so); 1015 sowwakeup(so); 1016 #endif 1017 } 1018 1019 static int 1020 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1021 { 1022 INIT_VNET_INET(curvnet); 1023 int error, i, m, n, pcb_count; 1024 struct inpcb *inp, **inp_list; 1025 inp_gen_t gencnt; 1026 struct xinpgen xig; 1027 1028 /* 1029 * The process of preparing the TCB list is too time-consuming and 1030 * resource-intensive to repeat twice on every request. 1031 */ 1032 if (req->oldptr == NULL) { 1033 m = syncache_pcbcount(); 1034 n = V_tcbinfo.ipi_count; 1035 req->oldidx = 2 * (sizeof xig) 1036 + ((m + n) + n/8) * sizeof(struct xtcpcb); 1037 return (0); 1038 } 1039 1040 if (req->newptr != NULL) 1041 return (EPERM); 1042 1043 /* 1044 * OK, now we're committed to doing something. 1045 */ 1046 INP_INFO_RLOCK(&V_tcbinfo); 1047 gencnt = V_tcbinfo.ipi_gencnt; 1048 n = V_tcbinfo.ipi_count; 1049 INP_INFO_RUNLOCK(&V_tcbinfo); 1050 1051 m = syncache_pcbcount(); 1052 1053 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 1054 + (n + m) * sizeof(struct xtcpcb)); 1055 if (error != 0) 1056 return (error); 1057 1058 xig.xig_len = sizeof xig; 1059 xig.xig_count = n + m; 1060 xig.xig_gen = gencnt; 1061 xig.xig_sogen = so_gencnt; 1062 error = SYSCTL_OUT(req, &xig, sizeof xig); 1063 if (error) 1064 return (error); 1065 1066 error = syncache_pcblist(req, m, &pcb_count); 1067 if (error) 1068 return (error); 1069 1070 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 1071 if (inp_list == NULL) 1072 return (ENOMEM); 1073 1074 INP_INFO_RLOCK(&V_tcbinfo); 1075 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0; 1076 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) { 1077 INP_RLOCK(inp); 1078 if (inp->inp_gencnt <= gencnt) { 1079 /* 1080 * XXX: This use of cr_cansee(), introduced with 1081 * TCP state changes, is not quite right, but for 1082 * now, better than nothing. 1083 */ 1084 if (inp->inp_flags & INP_TIMEWAIT) { 1085 if (intotw(inp) != NULL) 1086 error = cr_cansee(req->td->td_ucred, 1087 intotw(inp)->tw_cred); 1088 else 1089 error = EINVAL; /* Skip this inp. */ 1090 } else 1091 error = cr_canseeinpcb(req->td->td_ucred, inp); 1092 if (error == 0) 1093 inp_list[i++] = inp; 1094 } 1095 INP_RUNLOCK(inp); 1096 } 1097 INP_INFO_RUNLOCK(&V_tcbinfo); 1098 n = i; 1099 1100 error = 0; 1101 for (i = 0; i < n; i++) { 1102 inp = inp_list[i]; 1103 INP_RLOCK(inp); 1104 if (inp->inp_gencnt <= gencnt) { 1105 struct xtcpcb xt; 1106 void *inp_ppcb; 1107 1108 bzero(&xt, sizeof(xt)); 1109 xt.xt_len = sizeof xt; 1110 /* XXX should avoid extra copy */ 1111 bcopy(inp, &xt.xt_inp, sizeof *inp); 1112 inp_ppcb = inp->inp_ppcb; 1113 if (inp_ppcb == NULL) 1114 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1115 else if (inp->inp_flags & INP_TIMEWAIT) { 1116 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1117 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1118 } else 1119 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1120 if (inp->inp_socket != NULL) 1121 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1122 else { 1123 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1124 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1125 } 1126 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1127 INP_RUNLOCK(inp); 1128 error = SYSCTL_OUT(req, &xt, sizeof xt); 1129 } else 1130 INP_RUNLOCK(inp); 1131 1132 } 1133 if (!error) { 1134 /* 1135 * Give the user an updated idea of our state. 1136 * If the generation differs from what we told 1137 * her before, she knows that something happened 1138 * while we were processing this request, and it 1139 * might be necessary to retry. 1140 */ 1141 INP_INFO_RLOCK(&V_tcbinfo); 1142 xig.xig_gen = V_tcbinfo.ipi_gencnt; 1143 xig.xig_sogen = so_gencnt; 1144 xig.xig_count = V_tcbinfo.ipi_count + pcb_count; 1145 INP_INFO_RUNLOCK(&V_tcbinfo); 1146 error = SYSCTL_OUT(req, &xig, sizeof xig); 1147 } 1148 free(inp_list, M_TEMP); 1149 return (error); 1150 } 1151 1152 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1153 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1154 1155 static int 1156 tcp_getcred(SYSCTL_HANDLER_ARGS) 1157 { 1158 INIT_VNET_INET(curvnet); 1159 struct xucred xuc; 1160 struct sockaddr_in addrs[2]; 1161 struct inpcb *inp; 1162 int error; 1163 1164 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1165 if (error) 1166 return (error); 1167 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1168 if (error) 1169 return (error); 1170 INP_INFO_RLOCK(&V_tcbinfo); 1171 inp = in_pcblookup_hash(&V_tcbinfo, addrs[1].sin_addr, 1172 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1173 if (inp != NULL) { 1174 INP_RLOCK(inp); 1175 INP_INFO_RUNLOCK(&V_tcbinfo); 1176 if (inp->inp_socket == NULL) 1177 error = ENOENT; 1178 if (error == 0) 1179 error = cr_canseeinpcb(req->td->td_ucred, inp); 1180 if (error == 0) 1181 cru2x(inp->inp_cred, &xuc); 1182 INP_RUNLOCK(inp); 1183 } else { 1184 INP_INFO_RUNLOCK(&V_tcbinfo); 1185 error = ENOENT; 1186 } 1187 if (error == 0) 1188 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1189 return (error); 1190 } 1191 1192 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1193 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1194 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1195 1196 #ifdef INET6 1197 static int 1198 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1199 { 1200 INIT_VNET_INET(curvnet); 1201 INIT_VNET_INET6(curvnet); 1202 struct xucred xuc; 1203 struct sockaddr_in6 addrs[2]; 1204 struct inpcb *inp; 1205 int error, mapped = 0; 1206 1207 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1208 if (error) 1209 return (error); 1210 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1211 if (error) 1212 return (error); 1213 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 || 1214 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) { 1215 return (error); 1216 } 1217 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1218 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1219 mapped = 1; 1220 else 1221 return (EINVAL); 1222 } 1223 1224 INP_INFO_RLOCK(&V_tcbinfo); 1225 if (mapped == 1) 1226 inp = in_pcblookup_hash(&V_tcbinfo, 1227 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1228 addrs[1].sin6_port, 1229 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1230 addrs[0].sin6_port, 1231 0, NULL); 1232 else 1233 inp = in6_pcblookup_hash(&V_tcbinfo, 1234 &addrs[1].sin6_addr, addrs[1].sin6_port, 1235 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1236 if (inp != NULL) { 1237 INP_RLOCK(inp); 1238 INP_INFO_RUNLOCK(&V_tcbinfo); 1239 if (inp->inp_socket == NULL) 1240 error = ENOENT; 1241 if (error == 0) 1242 error = cr_canseeinpcb(req->td->td_ucred, inp); 1243 if (error == 0) 1244 cru2x(inp->inp_cred, &xuc); 1245 INP_RUNLOCK(inp); 1246 } else { 1247 INP_INFO_RUNLOCK(&V_tcbinfo); 1248 error = ENOENT; 1249 } 1250 if (error == 0) 1251 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1252 return (error); 1253 } 1254 1255 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1256 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1257 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1258 #endif 1259 1260 1261 void 1262 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1263 { 1264 INIT_VNET_INET(curvnet); 1265 struct ip *ip = vip; 1266 struct tcphdr *th; 1267 struct in_addr faddr; 1268 struct inpcb *inp; 1269 struct tcpcb *tp; 1270 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1271 struct icmp *icp; 1272 struct in_conninfo inc; 1273 tcp_seq icmp_tcp_seq; 1274 int mtu; 1275 1276 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1277 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1278 return; 1279 1280 if (cmd == PRC_MSGSIZE) 1281 notify = tcp_mtudisc; 1282 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1283 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1284 notify = tcp_drop_syn_sent; 1285 /* 1286 * Redirects don't need to be handled up here. 1287 */ 1288 else if (PRC_IS_REDIRECT(cmd)) 1289 return; 1290 /* 1291 * Source quench is depreciated. 1292 */ 1293 else if (cmd == PRC_QUENCH) 1294 return; 1295 /* 1296 * Hostdead is ugly because it goes linearly through all PCBs. 1297 * XXX: We never get this from ICMP, otherwise it makes an 1298 * excellent DoS attack on machines with many connections. 1299 */ 1300 else if (cmd == PRC_HOSTDEAD) 1301 ip = NULL; 1302 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1303 return; 1304 if (ip != NULL) { 1305 icp = (struct icmp *)((caddr_t)ip 1306 - offsetof(struct icmp, icmp_ip)); 1307 th = (struct tcphdr *)((caddr_t)ip 1308 + (ip->ip_hl << 2)); 1309 INP_INFO_WLOCK(&V_tcbinfo); 1310 inp = in_pcblookup_hash(&V_tcbinfo, faddr, th->th_dport, 1311 ip->ip_src, th->th_sport, 0, NULL); 1312 if (inp != NULL) { 1313 INP_WLOCK(inp); 1314 if (!(inp->inp_flags & INP_TIMEWAIT) && 1315 !(inp->inp_flags & INP_DROPPED) && 1316 !(inp->inp_socket == NULL)) { 1317 icmp_tcp_seq = htonl(th->th_seq); 1318 tp = intotcpcb(inp); 1319 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1320 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1321 if (cmd == PRC_MSGSIZE) { 1322 /* 1323 * MTU discovery: 1324 * If we got a needfrag set the MTU 1325 * in the route to the suggested new 1326 * value (if given) and then notify. 1327 */ 1328 bzero(&inc, sizeof(inc)); 1329 inc.inc_faddr = faddr; 1330 inc.inc_fibnum = 1331 inp->inp_inc.inc_fibnum; 1332 1333 mtu = ntohs(icp->icmp_nextmtu); 1334 /* 1335 * If no alternative MTU was 1336 * proposed, try the next smaller 1337 * one. ip->ip_len has already 1338 * been swapped in icmp_input(). 1339 */ 1340 if (!mtu) 1341 mtu = ip_next_mtu(ip->ip_len, 1342 1); 1343 if (mtu < max(296, V_tcp_minmss 1344 + sizeof(struct tcpiphdr))) 1345 mtu = 0; 1346 if (!mtu) 1347 mtu = V_tcp_mssdflt 1348 + sizeof(struct tcpiphdr); 1349 /* 1350 * Only cache the the MTU if it 1351 * is smaller than the interface 1352 * or route MTU. tcp_mtudisc() 1353 * will do right thing by itself. 1354 */ 1355 if (mtu <= tcp_maxmtu(&inc, NULL)) 1356 tcp_hc_updatemtu(&inc, mtu); 1357 } 1358 1359 inp = (*notify)(inp, inetctlerrmap[cmd]); 1360 } 1361 } 1362 if (inp != NULL) 1363 INP_WUNLOCK(inp); 1364 } else { 1365 bzero(&inc, sizeof(inc)); 1366 inc.inc_fport = th->th_dport; 1367 inc.inc_lport = th->th_sport; 1368 inc.inc_faddr = faddr; 1369 inc.inc_laddr = ip->ip_src; 1370 syncache_unreach(&inc, th); 1371 } 1372 INP_INFO_WUNLOCK(&V_tcbinfo); 1373 } else 1374 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify); 1375 } 1376 1377 #ifdef INET6 1378 void 1379 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1380 { 1381 INIT_VNET_INET(curvnet); 1382 struct tcphdr th; 1383 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1384 struct ip6_hdr *ip6; 1385 struct mbuf *m; 1386 struct ip6ctlparam *ip6cp = NULL; 1387 const struct sockaddr_in6 *sa6_src = NULL; 1388 int off; 1389 struct tcp_portonly { 1390 u_int16_t th_sport; 1391 u_int16_t th_dport; 1392 } *thp; 1393 1394 if (sa->sa_family != AF_INET6 || 1395 sa->sa_len != sizeof(struct sockaddr_in6)) 1396 return; 1397 1398 if (cmd == PRC_MSGSIZE) 1399 notify = tcp_mtudisc; 1400 else if (!PRC_IS_REDIRECT(cmd) && 1401 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1402 return; 1403 /* Source quench is depreciated. */ 1404 else if (cmd == PRC_QUENCH) 1405 return; 1406 1407 /* if the parameter is from icmp6, decode it. */ 1408 if (d != NULL) { 1409 ip6cp = (struct ip6ctlparam *)d; 1410 m = ip6cp->ip6c_m; 1411 ip6 = ip6cp->ip6c_ip6; 1412 off = ip6cp->ip6c_off; 1413 sa6_src = ip6cp->ip6c_src; 1414 } else { 1415 m = NULL; 1416 ip6 = NULL; 1417 off = 0; /* fool gcc */ 1418 sa6_src = &sa6_any; 1419 } 1420 1421 if (ip6 != NULL) { 1422 struct in_conninfo inc; 1423 /* 1424 * XXX: We assume that when IPV6 is non NULL, 1425 * M and OFF are valid. 1426 */ 1427 1428 /* check if we can safely examine src and dst ports */ 1429 if (m->m_pkthdr.len < off + sizeof(*thp)) 1430 return; 1431 1432 bzero(&th, sizeof(th)); 1433 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1434 1435 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport, 1436 (struct sockaddr *)ip6cp->ip6c_src, 1437 th.th_sport, cmd, NULL, notify); 1438 1439 bzero(&inc, sizeof(inc)); 1440 inc.inc_fport = th.th_dport; 1441 inc.inc_lport = th.th_sport; 1442 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1443 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1444 inc.inc_flags |= INC_ISIPV6; 1445 INP_INFO_WLOCK(&V_tcbinfo); 1446 syncache_unreach(&inc, &th); 1447 INP_INFO_WUNLOCK(&V_tcbinfo); 1448 } else 1449 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1450 0, cmd, NULL, notify); 1451 } 1452 #endif /* INET6 */ 1453 1454 1455 /* 1456 * Following is where TCP initial sequence number generation occurs. 1457 * 1458 * There are two places where we must use initial sequence numbers: 1459 * 1. In SYN-ACK packets. 1460 * 2. In SYN packets. 1461 * 1462 * All ISNs for SYN-ACK packets are generated by the syncache. See 1463 * tcp_syncache.c for details. 1464 * 1465 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1466 * depends on this property. In addition, these ISNs should be 1467 * unguessable so as to prevent connection hijacking. To satisfy 1468 * the requirements of this situation, the algorithm outlined in 1469 * RFC 1948 is used, with only small modifications. 1470 * 1471 * Implementation details: 1472 * 1473 * Time is based off the system timer, and is corrected so that it 1474 * increases by one megabyte per second. This allows for proper 1475 * recycling on high speed LANs while still leaving over an hour 1476 * before rollover. 1477 * 1478 * As reading the *exact* system time is too expensive to be done 1479 * whenever setting up a TCP connection, we increment the time 1480 * offset in two ways. First, a small random positive increment 1481 * is added to isn_offset for each connection that is set up. 1482 * Second, the function tcp_isn_tick fires once per clock tick 1483 * and increments isn_offset as necessary so that sequence numbers 1484 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1485 * random positive increments serve only to ensure that the same 1486 * exact sequence number is never sent out twice (as could otherwise 1487 * happen when a port is recycled in less than the system tick 1488 * interval.) 1489 * 1490 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1491 * between seeding of isn_secret. This is normally set to zero, 1492 * as reseeding should not be necessary. 1493 * 1494 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1495 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1496 * general, this means holding an exclusive (write) lock. 1497 */ 1498 1499 #define ISN_BYTES_PER_SECOND 1048576 1500 #define ISN_STATIC_INCREMENT 4096 1501 #define ISN_RANDOM_INCREMENT (4096 - 1) 1502 1503 #ifdef VIMAGE_GLOBALS 1504 static u_char isn_secret[32]; 1505 static int isn_last_reseed; 1506 static u_int32_t isn_offset, isn_offset_old; 1507 #endif 1508 1509 tcp_seq 1510 tcp_new_isn(struct tcpcb *tp) 1511 { 1512 INIT_VNET_INET(tp->t_vnet); 1513 MD5_CTX isn_ctx; 1514 u_int32_t md5_buffer[4]; 1515 tcp_seq new_isn; 1516 1517 INP_WLOCK_ASSERT(tp->t_inpcb); 1518 1519 ISN_LOCK(); 1520 /* Seed if this is the first use, reseed if requested. */ 1521 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) && 1522 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz) 1523 < (u_int)ticks))) { 1524 read_random(&V_isn_secret, sizeof(V_isn_secret)); 1525 V_isn_last_reseed = ticks; 1526 } 1527 1528 /* Compute the md5 hash and return the ISN. */ 1529 MD5Init(&isn_ctx); 1530 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1531 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1532 #ifdef INET6 1533 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1534 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1535 sizeof(struct in6_addr)); 1536 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1537 sizeof(struct in6_addr)); 1538 } else 1539 #endif 1540 { 1541 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1542 sizeof(struct in_addr)); 1543 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1544 sizeof(struct in_addr)); 1545 } 1546 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret)); 1547 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1548 new_isn = (tcp_seq) md5_buffer[0]; 1549 V_isn_offset += ISN_STATIC_INCREMENT + 1550 (arc4random() & ISN_RANDOM_INCREMENT); 1551 new_isn += V_isn_offset; 1552 ISN_UNLOCK(); 1553 return (new_isn); 1554 } 1555 1556 /* 1557 * Increment the offset to the next ISN_BYTES_PER_SECOND / 100 boundary 1558 * to keep time flowing at a relatively constant rate. If the random 1559 * increments have already pushed us past the projected offset, do nothing. 1560 */ 1561 static void 1562 tcp_isn_tick(void *xtp) 1563 { 1564 VNET_ITERATOR_DECL(vnet_iter); 1565 u_int32_t projected_offset; 1566 1567 VNET_LIST_RLOCK(); 1568 ISN_LOCK(); 1569 VNET_FOREACH(vnet_iter) { 1570 CURVNET_SET(vnet_iter); /* XXX appease INVARIANTS */ 1571 INIT_VNET_INET(curvnet); 1572 projected_offset = 1573 V_isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1574 1575 if (SEQ_GT(projected_offset, V_isn_offset)) 1576 V_isn_offset = projected_offset; 1577 1578 V_isn_offset_old = V_isn_offset; 1579 CURVNET_RESTORE(); 1580 } 1581 ISN_UNLOCK(); 1582 VNET_LIST_RUNLOCK(); 1583 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1584 } 1585 1586 /* 1587 * When a specific ICMP unreachable message is received and the 1588 * connection state is SYN-SENT, drop the connection. This behavior 1589 * is controlled by the icmp_may_rst sysctl. 1590 */ 1591 struct inpcb * 1592 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1593 { 1594 #ifdef INVARIANTS 1595 INIT_VNET_INET(inp->inp_vnet); 1596 #endif 1597 struct tcpcb *tp; 1598 1599 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 1600 INP_WLOCK_ASSERT(inp); 1601 1602 if ((inp->inp_flags & INP_TIMEWAIT) || 1603 (inp->inp_flags & INP_DROPPED)) 1604 return (inp); 1605 1606 tp = intotcpcb(inp); 1607 if (tp->t_state != TCPS_SYN_SENT) 1608 return (inp); 1609 1610 tp = tcp_drop(tp, errno); 1611 if (tp != NULL) 1612 return (inp); 1613 else 1614 return (NULL); 1615 } 1616 1617 /* 1618 * When `need fragmentation' ICMP is received, update our idea of the MSS 1619 * based on the new value in the route. Also nudge TCP to send something, 1620 * since we know the packet we just sent was dropped. 1621 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1622 */ 1623 struct inpcb * 1624 tcp_mtudisc(struct inpcb *inp, int errno) 1625 { 1626 INIT_VNET_INET(inp->inp_vnet); 1627 struct tcpcb *tp; 1628 struct socket *so; 1629 1630 INP_WLOCK_ASSERT(inp); 1631 if ((inp->inp_flags & INP_TIMEWAIT) || 1632 (inp->inp_flags & INP_DROPPED)) 1633 return (inp); 1634 1635 tp = intotcpcb(inp); 1636 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1637 1638 tcp_mss_update(tp, -1, NULL, NULL); 1639 1640 so = inp->inp_socket; 1641 SOCKBUF_LOCK(&so->so_snd); 1642 /* If the mss is larger than the socket buffer, decrease the mss. */ 1643 if (so->so_snd.sb_hiwat < tp->t_maxseg) 1644 tp->t_maxseg = so->so_snd.sb_hiwat; 1645 SOCKBUF_UNLOCK(&so->so_snd); 1646 1647 TCPSTAT_INC(tcps_mturesent); 1648 tp->t_rtttime = 0; 1649 tp->snd_nxt = tp->snd_una; 1650 tcp_free_sackholes(tp); 1651 tp->snd_recover = tp->snd_max; 1652 if (tp->t_flags & TF_SACK_PERMIT) 1653 EXIT_FASTRECOVERY(tp); 1654 tcp_output_send(tp); 1655 return (inp); 1656 } 1657 1658 /* 1659 * Look-up the routing entry to the peer of this inpcb. If no route 1660 * is found and it cannot be allocated, then return 0. This routine 1661 * is called by TCP routines that access the rmx structure and by 1662 * tcp_mss_update to get the peer/interface MTU. 1663 */ 1664 u_long 1665 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1666 { 1667 struct route sro; 1668 struct sockaddr_in *dst; 1669 struct ifnet *ifp; 1670 u_long maxmtu = 0; 1671 1672 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1673 1674 bzero(&sro, sizeof(sro)); 1675 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1676 dst = (struct sockaddr_in *)&sro.ro_dst; 1677 dst->sin_family = AF_INET; 1678 dst->sin_len = sizeof(*dst); 1679 dst->sin_addr = inc->inc_faddr; 1680 in_rtalloc_ign(&sro, 0, inc->inc_fibnum); 1681 } 1682 if (sro.ro_rt != NULL) { 1683 ifp = sro.ro_rt->rt_ifp; 1684 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1685 maxmtu = ifp->if_mtu; 1686 else 1687 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1688 1689 /* Report additional interface capabilities. */ 1690 if (flags != NULL) { 1691 if (ifp->if_capenable & IFCAP_TSO4 && 1692 ifp->if_hwassist & CSUM_TSO) 1693 *flags |= CSUM_TSO; 1694 } 1695 RTFREE(sro.ro_rt); 1696 } 1697 return (maxmtu); 1698 } 1699 1700 #ifdef INET6 1701 u_long 1702 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1703 { 1704 struct route_in6 sro6; 1705 struct ifnet *ifp; 1706 u_long maxmtu = 0; 1707 1708 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1709 1710 bzero(&sro6, sizeof(sro6)); 1711 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1712 sro6.ro_dst.sin6_family = AF_INET6; 1713 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1714 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1715 rtalloc_ign((struct route *)&sro6, 0); 1716 } 1717 if (sro6.ro_rt != NULL) { 1718 ifp = sro6.ro_rt->rt_ifp; 1719 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1720 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1721 else 1722 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1723 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1724 1725 /* Report additional interface capabilities. */ 1726 if (flags != NULL) { 1727 if (ifp->if_capenable & IFCAP_TSO6 && 1728 ifp->if_hwassist & CSUM_TSO) 1729 *flags |= CSUM_TSO; 1730 } 1731 RTFREE(sro6.ro_rt); 1732 } 1733 1734 return (maxmtu); 1735 } 1736 #endif /* INET6 */ 1737 1738 #ifdef IPSEC 1739 /* compute ESP/AH header size for TCP, including outer IP header. */ 1740 size_t 1741 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1742 { 1743 struct inpcb *inp; 1744 struct mbuf *m; 1745 size_t hdrsiz; 1746 struct ip *ip; 1747 #ifdef INET6 1748 struct ip6_hdr *ip6; 1749 #endif 1750 struct tcphdr *th; 1751 1752 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1753 return (0); 1754 MGETHDR(m, M_DONTWAIT, MT_DATA); 1755 if (!m) 1756 return (0); 1757 1758 #ifdef INET6 1759 if ((inp->inp_vflag & INP_IPV6) != 0) { 1760 ip6 = mtod(m, struct ip6_hdr *); 1761 th = (struct tcphdr *)(ip6 + 1); 1762 m->m_pkthdr.len = m->m_len = 1763 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1764 tcpip_fillheaders(inp, ip6, th); 1765 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1766 } else 1767 #endif /* INET6 */ 1768 { 1769 ip = mtod(m, struct ip *); 1770 th = (struct tcphdr *)(ip + 1); 1771 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1772 tcpip_fillheaders(inp, ip, th); 1773 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1774 } 1775 1776 m_free(m); 1777 return (hdrsiz); 1778 } 1779 #endif /* IPSEC */ 1780 1781 /* 1782 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1783 * 1784 * This code attempts to calculate the bandwidth-delay product as a 1785 * means of determining the optimal window size to maximize bandwidth, 1786 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1787 * routers. This code also does a fairly good job keeping RTTs in check 1788 * across slow links like modems. We implement an algorithm which is very 1789 * similar (but not meant to be) TCP/Vegas. The code operates on the 1790 * transmitter side of a TCP connection and so only effects the transmit 1791 * side of the connection. 1792 * 1793 * BACKGROUND: TCP makes no provision for the management of buffer space 1794 * at the end points or at the intermediate routers and switches. A TCP 1795 * stream, whether using NewReno or not, will eventually buffer as 1796 * many packets as it is able and the only reason this typically works is 1797 * due to the fairly small default buffers made available for a connection 1798 * (typicaly 16K or 32K). As machines use larger windows and/or window 1799 * scaling it is now fairly easy for even a single TCP connection to blow-out 1800 * all available buffer space not only on the local interface, but on 1801 * intermediate routers and switches as well. NewReno makes a misguided 1802 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1803 * then backing off, then steadily increasing the window again until another 1804 * failure occurs, ad-infinitum. This results in terrible oscillation that 1805 * is only made worse as network loads increase and the idea of intentionally 1806 * blowing out network buffers is, frankly, a terrible way to manage network 1807 * resources. 1808 * 1809 * It is far better to limit the transmit window prior to the failure 1810 * condition being achieved. There are two general ways to do this: First 1811 * you can 'scan' through different transmit window sizes and locate the 1812 * point where the RTT stops increasing, indicating that you have filled the 1813 * pipe, then scan backwards until you note that RTT stops decreasing, then 1814 * repeat ad-infinitum. This method works in principle but has severe 1815 * implementation issues due to RTT variances, timer granularity, and 1816 * instability in the algorithm which can lead to many false positives and 1817 * create oscillations as well as interact badly with other TCP streams 1818 * implementing the same algorithm. 1819 * 1820 * The second method is to limit the window to the bandwidth delay product 1821 * of the link. This is the method we implement. RTT variances and our 1822 * own manipulation of the congestion window, bwnd, can potentially 1823 * destabilize the algorithm. For this reason we have to stabilize the 1824 * elements used to calculate the window. We do this by using the minimum 1825 * observed RTT, the long term average of the observed bandwidth, and 1826 * by adding two segments worth of slop. It isn't perfect but it is able 1827 * to react to changing conditions and gives us a very stable basis on 1828 * which to extend the algorithm. 1829 */ 1830 void 1831 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1832 { 1833 INIT_VNET_INET(tp->t_vnet); 1834 u_long bw; 1835 u_long bwnd; 1836 int save_ticks; 1837 1838 INP_WLOCK_ASSERT(tp->t_inpcb); 1839 1840 /* 1841 * If inflight_enable is disabled in the middle of a tcp connection, 1842 * make sure snd_bwnd is effectively disabled. 1843 */ 1844 if (V_tcp_inflight_enable == 0 || 1845 tp->t_rttlow < V_tcp_inflight_rttthresh) { 1846 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1847 tp->snd_bandwidth = 0; 1848 return; 1849 } 1850 1851 /* 1852 * Figure out the bandwidth. Due to the tick granularity this 1853 * is a very rough number and it MUST be averaged over a fairly 1854 * long period of time. XXX we need to take into account a link 1855 * that is not using all available bandwidth, but for now our 1856 * slop will ramp us up if this case occurs and the bandwidth later 1857 * increases. 1858 * 1859 * Note: if ticks rollover 'bw' may wind up negative. We must 1860 * effectively reset t_bw_rtttime for this case. 1861 */ 1862 save_ticks = ticks; 1863 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 1864 return; 1865 1866 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 1867 (save_ticks - tp->t_bw_rtttime); 1868 tp->t_bw_rtttime = save_ticks; 1869 tp->t_bw_rtseq = ack_seq; 1870 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 1871 return; 1872 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1873 1874 tp->snd_bandwidth = bw; 1875 1876 /* 1877 * Calculate the semi-static bandwidth delay product, plus two maximal 1878 * segments. The additional slop puts us squarely in the sweet 1879 * spot and also handles the bandwidth run-up case and stabilization. 1880 * Without the slop we could be locking ourselves into a lower 1881 * bandwidth. 1882 * 1883 * Situations Handled: 1884 * (1) Prevents over-queueing of packets on LANs, especially on 1885 * high speed LANs, allowing larger TCP buffers to be 1886 * specified, and also does a good job preventing 1887 * over-queueing of packets over choke points like modems 1888 * (at least for the transmit side). 1889 * 1890 * (2) Is able to handle changing network loads (bandwidth 1891 * drops so bwnd drops, bandwidth increases so bwnd 1892 * increases). 1893 * 1894 * (3) Theoretically should stabilize in the face of multiple 1895 * connections implementing the same algorithm (this may need 1896 * a little work). 1897 * 1898 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1899 * be adjusted with a sysctl but typically only needs to be 1900 * on very slow connections. A value no smaller then 5 1901 * should be used, but only reduce this default if you have 1902 * no other choice. 1903 */ 1904 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1905 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + V_tcp_inflight_stab * tp->t_maxseg / 10; 1906 #undef USERTT 1907 1908 if (tcp_inflight_debug > 0) { 1909 static int ltime; 1910 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1911 ltime = ticks; 1912 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1913 tp, 1914 bw, 1915 tp->t_rttbest, 1916 tp->t_srtt, 1917 bwnd 1918 ); 1919 } 1920 } 1921 if ((long)bwnd < V_tcp_inflight_min) 1922 bwnd = V_tcp_inflight_min; 1923 if (bwnd > V_tcp_inflight_max) 1924 bwnd = V_tcp_inflight_max; 1925 if ((long)bwnd < tp->t_maxseg * 2) 1926 bwnd = tp->t_maxseg * 2; 1927 tp->snd_bwnd = bwnd; 1928 } 1929 1930 #ifdef TCP_SIGNATURE 1931 /* 1932 * Callback function invoked by m_apply() to digest TCP segment data 1933 * contained within an mbuf chain. 1934 */ 1935 static int 1936 tcp_signature_apply(void *fstate, void *data, u_int len) 1937 { 1938 1939 MD5Update(fstate, (u_char *)data, len); 1940 return (0); 1941 } 1942 1943 /* 1944 * Compute TCP-MD5 hash of a TCP segment. (RFC2385) 1945 * 1946 * Parameters: 1947 * m pointer to head of mbuf chain 1948 * _unused 1949 * len length of TCP segment data, excluding options 1950 * optlen length of TCP segment options 1951 * buf pointer to storage for computed MD5 digest 1952 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 1953 * 1954 * We do this over ip, tcphdr, segment data, and the key in the SADB. 1955 * When called from tcp_input(), we can be sure that th_sum has been 1956 * zeroed out and verified already. 1957 * 1958 * Return 0 if successful, otherwise return -1. 1959 * 1960 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 1961 * search with the destination IP address, and a 'magic SPI' to be 1962 * determined by the application. This is hardcoded elsewhere to 1179 1963 * right now. Another branch of this code exists which uses the SPD to 1964 * specify per-application flows but it is unstable. 1965 */ 1966 int 1967 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen, 1968 u_char *buf, u_int direction) 1969 { 1970 INIT_VNET_IPSEC(curvnet); 1971 union sockaddr_union dst; 1972 struct ippseudo ippseudo; 1973 MD5_CTX ctx; 1974 int doff; 1975 struct ip *ip; 1976 struct ipovly *ipovly; 1977 struct secasvar *sav; 1978 struct tcphdr *th; 1979 #ifdef INET6 1980 struct ip6_hdr *ip6; 1981 struct in6_addr in6; 1982 char ip6buf[INET6_ADDRSTRLEN]; 1983 uint32_t plen; 1984 uint16_t nhdr; 1985 #endif 1986 u_short savecsum; 1987 1988 KASSERT(m != NULL, ("NULL mbuf chain")); 1989 KASSERT(buf != NULL, ("NULL signature pointer")); 1990 1991 /* Extract the destination from the IP header in the mbuf. */ 1992 bzero(&dst, sizeof(union sockaddr_union)); 1993 ip = mtod(m, struct ip *); 1994 #ifdef INET6 1995 ip6 = NULL; /* Make the compiler happy. */ 1996 #endif 1997 switch (ip->ip_v) { 1998 case IPVERSION: 1999 dst.sa.sa_len = sizeof(struct sockaddr_in); 2000 dst.sa.sa_family = AF_INET; 2001 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 2002 ip->ip_src : ip->ip_dst; 2003 break; 2004 #ifdef INET6 2005 case (IPV6_VERSION >> 4): 2006 ip6 = mtod(m, struct ip6_hdr *); 2007 dst.sa.sa_len = sizeof(struct sockaddr_in6); 2008 dst.sa.sa_family = AF_INET6; 2009 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ? 2010 ip6->ip6_src : ip6->ip6_dst; 2011 break; 2012 #endif 2013 default: 2014 return (EINVAL); 2015 /* NOTREACHED */ 2016 break; 2017 } 2018 2019 /* Look up an SADB entry which matches the address of the peer. */ 2020 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2021 if (sav == NULL) { 2022 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__, 2023 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) : 2024 #ifdef INET6 2025 (ip->ip_v == (IPV6_VERSION >> 4)) ? 2026 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) : 2027 #endif 2028 "(unsupported)")); 2029 return (EINVAL); 2030 } 2031 2032 MD5Init(&ctx); 2033 /* 2034 * Step 1: Update MD5 hash with IP(v6) pseudo-header. 2035 * 2036 * XXX The ippseudo header MUST be digested in network byte order, 2037 * or else we'll fail the regression test. Assume all fields we've 2038 * been doing arithmetic on have been in host byte order. 2039 * XXX One cannot depend on ipovly->ih_len here. When called from 2040 * tcp_output(), the underlying ip_len member has not yet been set. 2041 */ 2042 switch (ip->ip_v) { 2043 case IPVERSION: 2044 ipovly = (struct ipovly *)ip; 2045 ippseudo.ippseudo_src = ipovly->ih_src; 2046 ippseudo.ippseudo_dst = ipovly->ih_dst; 2047 ippseudo.ippseudo_pad = 0; 2048 ippseudo.ippseudo_p = IPPROTO_TCP; 2049 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + 2050 optlen); 2051 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2052 2053 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip)); 2054 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen; 2055 break; 2056 #ifdef INET6 2057 /* 2058 * RFC 2385, 2.0 Proposal 2059 * For IPv6, the pseudo-header is as described in RFC 2460, namely the 2060 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero- 2061 * extended next header value (to form 32 bits), and 32-bit segment 2062 * length. 2063 * Note: Upper-Layer Packet Length comes before Next Header. 2064 */ 2065 case (IPV6_VERSION >> 4): 2066 in6 = ip6->ip6_src; 2067 in6_clearscope(&in6); 2068 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2069 in6 = ip6->ip6_dst; 2070 in6_clearscope(&in6); 2071 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2072 plen = htonl(len + sizeof(struct tcphdr) + optlen); 2073 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t)); 2074 nhdr = 0; 2075 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2076 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2077 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2078 nhdr = IPPROTO_TCP; 2079 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2080 2081 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr)); 2082 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen; 2083 break; 2084 #endif 2085 default: 2086 return (EINVAL); 2087 /* NOTREACHED */ 2088 break; 2089 } 2090 2091 2092 /* 2093 * Step 2: Update MD5 hash with TCP header, excluding options. 2094 * The TCP checksum must be set to zero. 2095 */ 2096 savecsum = th->th_sum; 2097 th->th_sum = 0; 2098 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2099 th->th_sum = savecsum; 2100 2101 /* 2102 * Step 3: Update MD5 hash with TCP segment data. 2103 * Use m_apply() to avoid an early m_pullup(). 2104 */ 2105 if (len > 0) 2106 m_apply(m, doff, len, tcp_signature_apply, &ctx); 2107 2108 /* 2109 * Step 4: Update MD5 hash with shared secret. 2110 */ 2111 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 2112 MD5Final(buf, &ctx); 2113 2114 key_sa_recordxfer(sav, m); 2115 KEY_FREESAV(&sav); 2116 return (0); 2117 } 2118 #endif /* TCP_SIGNATURE */ 2119 2120 static int 2121 sysctl_drop(SYSCTL_HANDLER_ARGS) 2122 { 2123 INIT_VNET_INET(curvnet); 2124 #ifdef INET6 2125 INIT_VNET_INET6(curvnet); 2126 #endif 2127 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 2128 struct sockaddr_storage addrs[2]; 2129 struct inpcb *inp; 2130 struct tcpcb *tp; 2131 struct tcptw *tw; 2132 struct sockaddr_in *fin, *lin; 2133 #ifdef INET6 2134 struct sockaddr_in6 *fin6, *lin6; 2135 #endif 2136 int error; 2137 2138 inp = NULL; 2139 fin = lin = NULL; 2140 #ifdef INET6 2141 fin6 = lin6 = NULL; 2142 #endif 2143 error = 0; 2144 2145 if (req->oldptr != NULL || req->oldlen != 0) 2146 return (EINVAL); 2147 if (req->newptr == NULL) 2148 return (EPERM); 2149 if (req->newlen < sizeof(addrs)) 2150 return (ENOMEM); 2151 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2152 if (error) 2153 return (error); 2154 2155 switch (addrs[0].ss_family) { 2156 #ifdef INET6 2157 case AF_INET6: 2158 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2159 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2160 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2161 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2162 return (EINVAL); 2163 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2164 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2165 return (EINVAL); 2166 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2167 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2168 fin = (struct sockaddr_in *)&addrs[0]; 2169 lin = (struct sockaddr_in *)&addrs[1]; 2170 break; 2171 } 2172 error = sa6_embedscope(fin6, V_ip6_use_defzone); 2173 if (error) 2174 return (error); 2175 error = sa6_embedscope(lin6, V_ip6_use_defzone); 2176 if (error) 2177 return (error); 2178 break; 2179 #endif 2180 case AF_INET: 2181 fin = (struct sockaddr_in *)&addrs[0]; 2182 lin = (struct sockaddr_in *)&addrs[1]; 2183 if (fin->sin_len != sizeof(struct sockaddr_in) || 2184 lin->sin_len != sizeof(struct sockaddr_in)) 2185 return (EINVAL); 2186 break; 2187 default: 2188 return (EINVAL); 2189 } 2190 INP_INFO_WLOCK(&V_tcbinfo); 2191 switch (addrs[0].ss_family) { 2192 #ifdef INET6 2193 case AF_INET6: 2194 inp = in6_pcblookup_hash(&V_tcbinfo, &fin6->sin6_addr, 2195 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port, 0, 2196 NULL); 2197 break; 2198 #endif 2199 case AF_INET: 2200 inp = in_pcblookup_hash(&V_tcbinfo, fin->sin_addr, 2201 fin->sin_port, lin->sin_addr, lin->sin_port, 0, NULL); 2202 break; 2203 } 2204 if (inp != NULL) { 2205 INP_WLOCK(inp); 2206 if (inp->inp_flags & INP_TIMEWAIT) { 2207 /* 2208 * XXXRW: There currently exists a state where an 2209 * inpcb is present, but its timewait state has been 2210 * discarded. For now, don't allow dropping of this 2211 * type of inpcb. 2212 */ 2213 tw = intotw(inp); 2214 if (tw != NULL) 2215 tcp_twclose(tw, 0); 2216 else 2217 INP_WUNLOCK(inp); 2218 } else if (!(inp->inp_flags & INP_DROPPED) && 2219 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2220 tp = intotcpcb(inp); 2221 tp = tcp_drop(tp, ECONNABORTED); 2222 if (tp != NULL) 2223 INP_WUNLOCK(inp); 2224 } else 2225 INP_WUNLOCK(inp); 2226 } else 2227 error = ESRCH; 2228 INP_INFO_WUNLOCK(&V_tcbinfo); 2229 return (error); 2230 } 2231 2232 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2233 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2234 0, sysctl_drop, "", "Drop TCP connection"); 2235 2236 /* 2237 * Generate a standardized TCP log line for use throughout the 2238 * tcp subsystem. Memory allocation is done with M_NOWAIT to 2239 * allow use in the interrupt context. 2240 * 2241 * NB: The caller MUST free(s, M_TCPLOG) the returned string. 2242 * NB: The function may return NULL if memory allocation failed. 2243 * 2244 * Due to header inclusion and ordering limitations the struct ip 2245 * and ip6_hdr pointers have to be passed as void pointers. 2246 */ 2247 char * 2248 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2249 const void *ip6hdr) 2250 { 2251 char *s, *sp; 2252 size_t size; 2253 struct ip *ip; 2254 #ifdef INET6 2255 const struct ip6_hdr *ip6; 2256 2257 ip6 = (const struct ip6_hdr *)ip6hdr; 2258 #endif /* INET6 */ 2259 ip = (struct ip *)ip4hdr; 2260 2261 /* 2262 * The log line looks like this: 2263 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>" 2264 */ 2265 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") + 2266 sizeof(PRINT_TH_FLAGS) + 1 + 2267 #ifdef INET6 2268 2 * INET6_ADDRSTRLEN; 2269 #else 2270 2 * INET_ADDRSTRLEN; 2271 #endif /* INET6 */ 2272 2273 /* Is logging enabled? */ 2274 if (tcp_log_debug == 0 && tcp_log_in_vain == 0) 2275 return (NULL); 2276 2277 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT); 2278 if (s == NULL) 2279 return (NULL); 2280 2281 strcat(s, "TCP: ["); 2282 sp = s + strlen(s); 2283 2284 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) { 2285 inet_ntoa_r(inc->inc_faddr, sp); 2286 sp = s + strlen(s); 2287 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2288 sp = s + strlen(s); 2289 inet_ntoa_r(inc->inc_laddr, sp); 2290 sp = s + strlen(s); 2291 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2292 #ifdef INET6 2293 } else if (inc) { 2294 ip6_sprintf(sp, &inc->inc6_faddr); 2295 sp = s + strlen(s); 2296 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2297 sp = s + strlen(s); 2298 ip6_sprintf(sp, &inc->inc6_laddr); 2299 sp = s + strlen(s); 2300 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2301 } else if (ip6 && th) { 2302 ip6_sprintf(sp, &ip6->ip6_src); 2303 sp = s + strlen(s); 2304 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2305 sp = s + strlen(s); 2306 ip6_sprintf(sp, &ip6->ip6_dst); 2307 sp = s + strlen(s); 2308 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2309 #endif /* INET6 */ 2310 } else if (ip && th) { 2311 inet_ntoa_r(ip->ip_src, sp); 2312 sp = s + strlen(s); 2313 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2314 sp = s + strlen(s); 2315 inet_ntoa_r(ip->ip_dst, sp); 2316 sp = s + strlen(s); 2317 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2318 } else { 2319 free(s, M_TCPLOG); 2320 return (NULL); 2321 } 2322 sp = s + strlen(s); 2323 if (th) 2324 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS); 2325 if (*(s + size - 1) != '\0') 2326 panic("%s: string too long", __func__); 2327 return (s); 2328 } 2329