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_mac.h" 40 #include "opt_tcpdebug.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/callout.h> 45 #include <sys/kernel.h> 46 #include <sys/sysctl.h> 47 #include <sys/malloc.h> 48 #include <sys/mbuf.h> 49 #ifdef INET6 50 #include <sys/domain.h> 51 #endif 52 #include <sys/priv.h> 53 #include <sys/proc.h> 54 #include <sys/socket.h> 55 #include <sys/socketvar.h> 56 #include <sys/protosw.h> 57 #include <sys/random.h> 58 #include <sys/vimage.h> 59 60 #include <vm/uma.h> 61 62 #include <net/route.h> 63 #include <net/if.h> 64 65 #include <netinet/in.h> 66 #include <netinet/in_systm.h> 67 #include <netinet/ip.h> 68 #ifdef INET6 69 #include <netinet/ip6.h> 70 #endif 71 #include <netinet/in_pcb.h> 72 #ifdef INET6 73 #include <netinet6/in6_pcb.h> 74 #endif 75 #include <netinet/in_var.h> 76 #include <netinet/ip_var.h> 77 #ifdef INET6 78 #include <netinet6/ip6_var.h> 79 #include <netinet6/scope6_var.h> 80 #include <netinet6/nd6.h> 81 #endif 82 #include <netinet/ip_icmp.h> 83 #include <netinet/tcp.h> 84 #include <netinet/tcp_fsm.h> 85 #include <netinet/tcp_seq.h> 86 #include <netinet/tcp_timer.h> 87 #include <netinet/tcp_var.h> 88 #include <netinet/tcp_syncache.h> 89 #include <netinet/tcp_offload.h> 90 #ifdef INET6 91 #include <netinet6/tcp6_var.h> 92 #endif 93 #include <netinet/tcpip.h> 94 #ifdef TCPDEBUG 95 #include <netinet/tcp_debug.h> 96 #endif 97 #include <netinet/vinet.h> 98 #include <netinet6/ip6protosw.h> 99 #include <netinet6/vinet6.h> 100 101 #ifdef IPSEC 102 #include <netipsec/ipsec.h> 103 #include <netipsec/xform.h> 104 #ifdef INET6 105 #include <netipsec/ipsec6.h> 106 #endif 107 #include <netipsec/key.h> 108 #include <sys/syslog.h> 109 #endif /*IPSEC*/ 110 111 #include <machine/in_cksum.h> 112 #include <sys/md5.h> 113 114 #include <security/mac/mac_framework.h> 115 116 #ifdef VIMAGE_GLOBALS 117 int tcp_mssdflt; 118 #ifdef INET6 119 int tcp_v6mssdflt; 120 #endif 121 int tcp_minmss; 122 int tcp_do_rfc1323; 123 static int icmp_may_rst; 124 static int tcp_isn_reseed_interval; 125 static int tcp_inflight_enable; 126 static int tcp_inflight_rttthresh; 127 static int tcp_inflight_min; 128 static int tcp_inflight_max; 129 static int tcp_inflight_stab; 130 #endif 131 132 static int 133 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS) 134 { 135 INIT_VNET_INET(curvnet); 136 int error, new; 137 138 new = V_tcp_mssdflt; 139 error = sysctl_handle_int(oidp, &new, 0, req); 140 if (error == 0 && req->newptr) { 141 if (new < TCP_MINMSS) 142 error = EINVAL; 143 else 144 V_tcp_mssdflt = new; 145 } 146 return (error); 147 } 148 149 SYSCTL_V_PROC(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, 150 CTLTYPE_INT|CTLFLAG_RW, tcp_mssdflt, 0, 151 &sysctl_net_inet_tcp_mss_check, "I", 152 "Default TCP Maximum Segment Size"); 153 154 #ifdef INET6 155 static int 156 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS) 157 { 158 INIT_VNET_INET(curvnet); 159 int error, new; 160 161 new = V_tcp_v6mssdflt; 162 error = sysctl_handle_int(oidp, &new, 0, req); 163 if (error == 0 && req->newptr) { 164 if (new < TCP_MINMSS) 165 error = EINVAL; 166 else 167 V_tcp_v6mssdflt = new; 168 } 169 return (error); 170 } 171 172 SYSCTL_V_PROC(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 173 CTLTYPE_INT|CTLFLAG_RW, tcp_v6mssdflt, 0, 174 &sysctl_net_inet_tcp_mss_v6_check, "I", 175 "Default TCP Maximum Segment Size for IPv6"); 176 #endif 177 178 /* 179 * Minimum MSS we accept and use. This prevents DoS attacks where 180 * we are forced to a ridiculous low MSS like 20 and send hundreds 181 * of packets instead of one. The effect scales with the available 182 * bandwidth and quickly saturates the CPU and network interface 183 * with packet generation and sending. Set to zero to disable MINMSS 184 * checking. This setting prevents us from sending too small packets. 185 */ 186 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, minmss, 187 CTLFLAG_RW, tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 188 189 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, 190 CTLFLAG_RW, tcp_do_rfc1323, 0, 191 "Enable rfc1323 (high performance TCP) extensions"); 192 193 static int tcp_log_debug = 0; 194 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW, 195 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments"); 196 197 static int tcp_tcbhashsize = 0; 198 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 199 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 200 201 static int do_tcpdrain = 1; 202 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 203 "Enable tcp_drain routine for extra help when low on mbufs"); 204 205 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, pcbcount, 206 CTLFLAG_RD, tcbinfo.ipi_count, 0, "Number of active PCBs"); 207 208 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, icmp_may_rst, 209 CTLFLAG_RW, icmp_may_rst, 0, 210 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 211 212 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, isn_reseed_interval, 213 CTLFLAG_RW, tcp_isn_reseed_interval, 0, 214 "Seconds between reseeding of ISN secret"); 215 216 /* 217 * TCP bandwidth limiting sysctls. Note that the default lower bound of 218 * 1024 exists only for debugging. A good production default would be 219 * something like 6100. 220 */ 221 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0, 222 "TCP inflight data limiting"); 223 224 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, enable, 225 CTLFLAG_RW, tcp_inflight_enable, 0, 226 "Enable automatic TCP inflight data limiting"); 227 228 static int tcp_inflight_debug = 0; 229 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW, 230 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 231 232 SYSCTL_V_PROC(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, rttthresh, 233 CTLTYPE_INT|CTLFLAG_RW, tcp_inflight_rttthresh, 0, sysctl_msec_to_ticks, 234 "I", "RTT threshold below which inflight will deactivate itself"); 235 236 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, min, 237 CTLFLAG_RW, tcp_inflight_min, 0, "Lower-bound for TCP inflight window"); 238 239 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, max, 240 CTLFLAG_RW, tcp_inflight_max, 0, "Upper-bound for TCP inflight window"); 241 242 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, stab, 243 CTLFLAG_RW, tcp_inflight_stab, 0, 244 "Inflight Algorithm Stabilization 20 = 2 packets"); 245 246 #ifdef VIMAGE_GLOBALS 247 uma_zone_t sack_hole_zone; 248 #endif 249 250 static struct inpcb *tcp_notify(struct inpcb *, int); 251 static void tcp_isn_tick(void *); 252 253 /* 254 * Target size of TCP PCB hash tables. Must be a power of two. 255 * 256 * Note that this can be overridden by the kernel environment 257 * variable net.inet.tcp.tcbhashsize 258 */ 259 #ifndef TCBHASHSIZE 260 #define TCBHASHSIZE 512 261 #endif 262 263 /* 264 * XXX 265 * Callouts should be moved into struct tcp directly. They are currently 266 * separate because the tcpcb structure is exported to userland for sysctl 267 * parsing purposes, which do not know about callouts. 268 */ 269 struct tcpcb_mem { 270 struct tcpcb tcb; 271 struct tcp_timer tt; 272 }; 273 274 #ifdef VIMAGE_GLOBALS 275 static uma_zone_t tcpcb_zone; 276 #endif 277 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers"); 278 struct callout isn_callout; 279 static struct mtx isn_mtx; 280 281 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 282 #define ISN_LOCK() mtx_lock(&isn_mtx) 283 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 284 285 /* 286 * TCP initialization. 287 */ 288 static void 289 tcp_zone_change(void *tag) 290 { 291 INIT_VNET_INET(curvnet); 292 293 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 294 uma_zone_set_max(V_tcpcb_zone, maxsockets); 295 tcp_tw_zone_change(); 296 } 297 298 static int 299 tcp_inpcb_init(void *mem, int size, int flags) 300 { 301 struct inpcb *inp = mem; 302 303 INP_LOCK_INIT(inp, "inp", "tcpinp"); 304 return (0); 305 } 306 307 void 308 tcp_init(void) 309 { 310 INIT_VNET_INET(curvnet); 311 int hashsize; 312 313 V_blackhole = 0; 314 V_tcp_delack_enabled = 1; 315 V_drop_synfin = 0; 316 V_tcp_do_rfc3042 = 1; 317 V_tcp_do_rfc3390 = 1; 318 V_tcp_do_ecn = 0; 319 V_tcp_ecn_maxretries = 1; 320 V_tcp_insecure_rst = 0; 321 V_tcp_do_autorcvbuf = 1; 322 V_tcp_autorcvbuf_inc = 16*1024; 323 V_tcp_autorcvbuf_max = 256*1024; 324 V_tcp_do_rfc3465 = 1; 325 V_tcp_abc_l_var = 2; 326 327 V_tcp_mssdflt = TCP_MSS; 328 #ifdef INET6 329 V_tcp_v6mssdflt = TCP6_MSS; 330 #endif 331 V_tcp_minmss = TCP_MINMSS; 332 V_tcp_do_rfc1323 = 1; 333 V_icmp_may_rst = 1; 334 V_tcp_isn_reseed_interval = 0; 335 V_tcp_inflight_enable = 1; 336 V_tcp_inflight_min = 6144; 337 V_tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 338 V_tcp_inflight_stab = 20; 339 340 V_path_mtu_discovery = 1; 341 V_ss_fltsz = 1; 342 V_ss_fltsz_local = 4; 343 V_tcp_do_newreno = 1; 344 V_tcp_do_tso = 1; 345 V_tcp_do_autosndbuf = 1; 346 V_tcp_autosndbuf_inc = 8*1024; 347 V_tcp_autosndbuf_max = 256*1024; 348 349 V_nolocaltimewait = 0; 350 351 V_tcp_do_sack = 1; 352 V_tcp_sack_maxholes = 128; 353 V_tcp_sack_globalmaxholes = 65536; 354 V_tcp_sack_globalholes = 0; 355 356 V_tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 357 358 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack); 359 360 INP_INFO_LOCK_INIT(&V_tcbinfo, "tcp"); 361 LIST_INIT(&V_tcb); 362 V_tcbinfo.ipi_listhead = &V_tcb; 363 hashsize = TCBHASHSIZE; 364 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 365 if (!powerof2(hashsize)) { 366 printf("WARNING: TCB hash size not a power of 2\n"); 367 hashsize = 512; /* safe default */ 368 } 369 V_tcbinfo.ipi_hashbase = hashinit(hashsize, M_PCB, 370 &V_tcbinfo.ipi_hashmask); 371 V_tcbinfo.ipi_porthashbase = hashinit(hashsize, M_PCB, 372 &V_tcbinfo.ipi_porthashmask); 373 V_tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb), 374 NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 375 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 376 /* 377 * These have to be type stable for the benefit of the timers. 378 */ 379 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 380 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 381 uma_zone_set_max(V_tcpcb_zone, maxsockets); 382 tcp_tw_init(); 383 syncache_init(); 384 tcp_hc_init(); 385 tcp_reass_init(); 386 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 387 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 388 389 /* Skip initialization of globals for non-default instances. */ 390 if (!IS_DEFAULT_VNET(curvnet)) 391 return; 392 393 /* XXX virtualize those bellow? */ 394 tcp_delacktime = TCPTV_DELACK; 395 tcp_keepinit = TCPTV_KEEP_INIT; 396 tcp_keepidle = TCPTV_KEEP_IDLE; 397 tcp_keepintvl = TCPTV_KEEPINTVL; 398 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 399 tcp_msl = TCPTV_MSL; 400 tcp_rexmit_min = TCPTV_MIN; 401 if (tcp_rexmit_min < 1) 402 tcp_rexmit_min = 1; 403 tcp_rexmit_slop = TCPTV_CPU_VAR; 404 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 405 tcp_tcbhashsize = hashsize; 406 407 #ifdef INET6 408 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 409 #else /* INET6 */ 410 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 411 #endif /* INET6 */ 412 if (max_protohdr < TCP_MINPROTOHDR) 413 max_protohdr = TCP_MINPROTOHDR; 414 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 415 panic("tcp_init"); 416 #undef TCP_MINPROTOHDR 417 418 ISN_LOCK_INIT(); 419 callout_init(&isn_callout, CALLOUT_MPSAFE); 420 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 421 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 422 SHUTDOWN_PRI_DEFAULT); 423 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 424 EVENTHANDLER_PRI_ANY); 425 } 426 427 void 428 tcp_fini(void *xtp) 429 { 430 431 callout_stop(&isn_callout); 432 } 433 434 /* 435 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 436 * tcp_template used to store this data in mbufs, but we now recopy it out 437 * of the tcpcb each time to conserve mbufs. 438 */ 439 void 440 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 441 { 442 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 443 444 INP_WLOCK_ASSERT(inp); 445 446 #ifdef INET6 447 if ((inp->inp_vflag & INP_IPV6) != 0) { 448 struct ip6_hdr *ip6; 449 450 ip6 = (struct ip6_hdr *)ip_ptr; 451 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 452 (inp->inp_flow & IPV6_FLOWINFO_MASK); 453 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 454 (IPV6_VERSION & IPV6_VERSION_MASK); 455 ip6->ip6_nxt = IPPROTO_TCP; 456 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 457 ip6->ip6_src = inp->in6p_laddr; 458 ip6->ip6_dst = inp->in6p_faddr; 459 } else 460 #endif 461 { 462 struct ip *ip; 463 464 ip = (struct ip *)ip_ptr; 465 ip->ip_v = IPVERSION; 466 ip->ip_hl = 5; 467 ip->ip_tos = inp->inp_ip_tos; 468 ip->ip_len = 0; 469 ip->ip_id = 0; 470 ip->ip_off = 0; 471 ip->ip_ttl = inp->inp_ip_ttl; 472 ip->ip_sum = 0; 473 ip->ip_p = IPPROTO_TCP; 474 ip->ip_src = inp->inp_laddr; 475 ip->ip_dst = inp->inp_faddr; 476 } 477 th->th_sport = inp->inp_lport; 478 th->th_dport = inp->inp_fport; 479 th->th_seq = 0; 480 th->th_ack = 0; 481 th->th_x2 = 0; 482 th->th_off = 5; 483 th->th_flags = 0; 484 th->th_win = 0; 485 th->th_urp = 0; 486 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 487 } 488 489 /* 490 * Create template to be used to send tcp packets on a connection. 491 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 492 * use for this function is in keepalives, which use tcp_respond. 493 */ 494 struct tcptemp * 495 tcpip_maketemplate(struct inpcb *inp) 496 { 497 struct tcptemp *t; 498 499 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT); 500 if (t == NULL) 501 return (NULL); 502 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t); 503 return (t); 504 } 505 506 /* 507 * Send a single message to the TCP at address specified by 508 * the given TCP/IP header. If m == NULL, then we make a copy 509 * of the tcpiphdr at ti and send directly to the addressed host. 510 * This is used to force keep alive messages out using the TCP 511 * template for a connection. If flags are given then we send 512 * a message back to the TCP which originated the * segment ti, 513 * and discard the mbuf containing it and any other attached mbufs. 514 * 515 * In any case the ack and sequence number of the transmitted 516 * segment are as specified by the parameters. 517 * 518 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 519 */ 520 void 521 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 522 tcp_seq ack, tcp_seq seq, int flags) 523 { 524 INIT_VNET_INET(curvnet); 525 int tlen; 526 int win = 0; 527 struct ip *ip; 528 struct tcphdr *nth; 529 #ifdef INET6 530 struct ip6_hdr *ip6; 531 int isipv6; 532 #endif /* INET6 */ 533 int ipflags = 0; 534 struct inpcb *inp; 535 536 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 537 538 #ifdef INET6 539 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 540 ip6 = ipgen; 541 #endif /* INET6 */ 542 ip = ipgen; 543 544 if (tp != NULL) { 545 inp = tp->t_inpcb; 546 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 547 INP_WLOCK_ASSERT(inp); 548 } else 549 inp = NULL; 550 551 if (tp != NULL) { 552 if (!(flags & TH_RST)) { 553 win = sbspace(&inp->inp_socket->so_rcv); 554 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 555 win = (long)TCP_MAXWIN << tp->rcv_scale; 556 } 557 } 558 if (m == NULL) { 559 m = m_gethdr(M_DONTWAIT, MT_DATA); 560 if (m == NULL) 561 return; 562 tlen = 0; 563 m->m_data += max_linkhdr; 564 #ifdef INET6 565 if (isipv6) { 566 bcopy((caddr_t)ip6, mtod(m, caddr_t), 567 sizeof(struct ip6_hdr)); 568 ip6 = mtod(m, struct ip6_hdr *); 569 nth = (struct tcphdr *)(ip6 + 1); 570 } else 571 #endif /* INET6 */ 572 { 573 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 574 ip = mtod(m, struct ip *); 575 nth = (struct tcphdr *)(ip + 1); 576 } 577 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 578 flags = TH_ACK; 579 } else { 580 /* 581 * reuse the mbuf. 582 * XXX MRT We inherrit the FIB, which is lucky. 583 */ 584 m_freem(m->m_next); 585 m->m_next = NULL; 586 m->m_data = (caddr_t)ipgen; 587 /* m_len is set later */ 588 tlen = 0; 589 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 590 #ifdef INET6 591 if (isipv6) { 592 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 593 nth = (struct tcphdr *)(ip6 + 1); 594 } else 595 #endif /* INET6 */ 596 { 597 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t); 598 nth = (struct tcphdr *)(ip + 1); 599 } 600 if (th != nth) { 601 /* 602 * this is usually a case when an extension header 603 * exists between the IPv6 header and the 604 * TCP header. 605 */ 606 nth->th_sport = th->th_sport; 607 nth->th_dport = th->th_dport; 608 } 609 xchg(nth->th_dport, nth->th_sport, uint16_t); 610 #undef xchg 611 } 612 #ifdef INET6 613 if (isipv6) { 614 ip6->ip6_flow = 0; 615 ip6->ip6_vfc = IPV6_VERSION; 616 ip6->ip6_nxt = IPPROTO_TCP; 617 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 618 tlen)); 619 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 620 } else 621 #endif 622 { 623 tlen += sizeof (struct tcpiphdr); 624 ip->ip_len = tlen; 625 ip->ip_ttl = V_ip_defttl; 626 if (V_path_mtu_discovery) 627 ip->ip_off |= IP_DF; 628 } 629 m->m_len = tlen; 630 m->m_pkthdr.len = tlen; 631 m->m_pkthdr.rcvif = NULL; 632 #ifdef MAC 633 if (inp != NULL) { 634 /* 635 * Packet is associated with a socket, so allow the 636 * label of the response to reflect the socket label. 637 */ 638 INP_WLOCK_ASSERT(inp); 639 mac_inpcb_create_mbuf(inp, m); 640 } else { 641 /* 642 * Packet is not associated with a socket, so possibly 643 * update the label in place. 644 */ 645 mac_netinet_tcp_reply(m); 646 } 647 #endif 648 nth->th_seq = htonl(seq); 649 nth->th_ack = htonl(ack); 650 nth->th_x2 = 0; 651 nth->th_off = sizeof (struct tcphdr) >> 2; 652 nth->th_flags = flags; 653 if (tp != NULL) 654 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 655 else 656 nth->th_win = htons((u_short)win); 657 nth->th_urp = 0; 658 #ifdef INET6 659 if (isipv6) { 660 nth->th_sum = 0; 661 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 662 sizeof(struct ip6_hdr), 663 tlen - sizeof(struct ip6_hdr)); 664 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 665 NULL, NULL); 666 } else 667 #endif /* INET6 */ 668 { 669 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 670 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 671 m->m_pkthdr.csum_flags = CSUM_TCP; 672 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 673 } 674 #ifdef TCPDEBUG 675 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 676 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 677 #endif 678 #ifdef INET6 679 if (isipv6) 680 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 681 else 682 #endif /* INET6 */ 683 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 684 } 685 686 /* 687 * Create a new TCP control block, making an 688 * empty reassembly queue and hooking it to the argument 689 * protocol control block. The `inp' parameter must have 690 * come from the zone allocator set up in tcp_init(). 691 */ 692 struct tcpcb * 693 tcp_newtcpcb(struct inpcb *inp) 694 { 695 INIT_VNET_INET(inp->inp_vnet); 696 struct tcpcb_mem *tm; 697 struct tcpcb *tp; 698 #ifdef INET6 699 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 700 #endif /* INET6 */ 701 702 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO); 703 if (tm == NULL) 704 return (NULL); 705 tp = &tm->tcb; 706 tp->t_timers = &tm->tt; 707 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 708 tp->t_maxseg = tp->t_maxopd = 709 #ifdef INET6 710 isipv6 ? V_tcp_v6mssdflt : 711 #endif /* INET6 */ 712 V_tcp_mssdflt; 713 714 /* Set up our timeouts. */ 715 callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE); 716 callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE); 717 callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE); 718 callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE); 719 callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE); 720 721 if (V_tcp_do_rfc1323) 722 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 723 if (V_tcp_do_sack) 724 tp->t_flags |= TF_SACK_PERMIT; 725 TAILQ_INIT(&tp->snd_holes); 726 tp->t_inpcb = inp; /* XXX */ 727 /* 728 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 729 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 730 * reasonable initial retransmit time. 731 */ 732 tp->t_srtt = TCPTV_SRTTBASE; 733 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 734 tp->t_rttmin = tcp_rexmit_min; 735 tp->t_rxtcur = TCPTV_RTOBASE; 736 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 737 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 738 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 739 tp->t_rcvtime = ticks; 740 tp->t_bw_rtttime = ticks; 741 /* 742 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 743 * because the socket may be bound to an IPv6 wildcard address, 744 * which may match an IPv4-mapped IPv6 address. 745 */ 746 inp->inp_ip_ttl = V_ip_defttl; 747 inp->inp_ppcb = tp; 748 return (tp); /* XXX */ 749 } 750 751 /* 752 * Drop a TCP connection, reporting 753 * the specified error. If connection is synchronized, 754 * then send a RST to peer. 755 */ 756 struct tcpcb * 757 tcp_drop(struct tcpcb *tp, int errno) 758 { 759 INIT_VNET_INET(tp->t_inpcb->inp_vnet); 760 struct socket *so = tp->t_inpcb->inp_socket; 761 762 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 763 INP_WLOCK_ASSERT(tp->t_inpcb); 764 765 if (TCPS_HAVERCVDSYN(tp->t_state)) { 766 tp->t_state = TCPS_CLOSED; 767 (void) tcp_output_reset(tp); 768 TCPSTAT_INC(tcps_drops); 769 } else 770 TCPSTAT_INC(tcps_conndrops); 771 if (errno == ETIMEDOUT && tp->t_softerror) 772 errno = tp->t_softerror; 773 so->so_error = errno; 774 return (tcp_close(tp)); 775 } 776 777 void 778 tcp_discardcb(struct tcpcb *tp) 779 { 780 INIT_VNET_INET(tp->t_vnet); 781 struct tseg_qent *q; 782 struct inpcb *inp = tp->t_inpcb; 783 struct socket *so = inp->inp_socket; 784 #ifdef INET6 785 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 786 #endif /* INET6 */ 787 788 INP_WLOCK_ASSERT(inp); 789 790 /* 791 * Make sure that all of our timers are stopped before we 792 * delete the PCB. 793 */ 794 callout_stop(&tp->t_timers->tt_rexmt); 795 callout_stop(&tp->t_timers->tt_persist); 796 callout_stop(&tp->t_timers->tt_keep); 797 callout_stop(&tp->t_timers->tt_2msl); 798 callout_stop(&tp->t_timers->tt_delack); 799 800 /* 801 * If we got enough samples through the srtt filter, 802 * save the rtt and rttvar in the routing entry. 803 * 'Enough' is arbitrarily defined as 4 rtt samples. 804 * 4 samples is enough for the srtt filter to converge 805 * to within enough % of the correct value; fewer samples 806 * and we could save a bogus rtt. The danger is not high 807 * as tcp quickly recovers from everything. 808 * XXX: Works very well but needs some more statistics! 809 */ 810 if (tp->t_rttupdated >= 4) { 811 struct hc_metrics_lite metrics; 812 u_long ssthresh; 813 814 bzero(&metrics, sizeof(metrics)); 815 /* 816 * Update the ssthresh always when the conditions below 817 * are satisfied. This gives us better new start value 818 * for the congestion avoidance for new connections. 819 * ssthresh is only set if packet loss occured on a session. 820 * 821 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 822 * being torn down. Ideally this code would not use 'so'. 823 */ 824 ssthresh = tp->snd_ssthresh; 825 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 826 /* 827 * convert the limit from user data bytes to 828 * packets then to packet data bytes. 829 */ 830 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 831 if (ssthresh < 2) 832 ssthresh = 2; 833 ssthresh *= (u_long)(tp->t_maxseg + 834 #ifdef INET6 835 (isipv6 ? sizeof (struct ip6_hdr) + 836 sizeof (struct tcphdr) : 837 #endif 838 sizeof (struct tcpiphdr) 839 #ifdef INET6 840 ) 841 #endif 842 ); 843 } else 844 ssthresh = 0; 845 metrics.rmx_ssthresh = ssthresh; 846 847 metrics.rmx_rtt = tp->t_srtt; 848 metrics.rmx_rttvar = tp->t_rttvar; 849 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 850 metrics.rmx_bandwidth = tp->snd_bandwidth; 851 metrics.rmx_cwnd = tp->snd_cwnd; 852 metrics.rmx_sendpipe = 0; 853 metrics.rmx_recvpipe = 0; 854 855 tcp_hc_update(&inp->inp_inc, &metrics); 856 } 857 858 /* free the reassembly queue, if any */ 859 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) { 860 LIST_REMOVE(q, tqe_q); 861 m_freem(q->tqe_m); 862 uma_zfree(V_tcp_reass_zone, q); 863 tp->t_segqlen--; 864 V_tcp_reass_qsize--; 865 } 866 /* Disconnect offload device, if any. */ 867 tcp_offload_detach(tp); 868 869 tcp_free_sackholes(tp); 870 inp->inp_ppcb = NULL; 871 tp->t_inpcb = NULL; 872 uma_zfree(V_tcpcb_zone, tp); 873 } 874 875 /* 876 * Attempt to close a TCP control block, marking it as dropped, and freeing 877 * the socket if we hold the only reference. 878 */ 879 struct tcpcb * 880 tcp_close(struct tcpcb *tp) 881 { 882 INIT_VNET_INET(tp->t_inpcb->inp_vnet); 883 struct inpcb *inp = tp->t_inpcb; 884 struct socket *so; 885 886 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 887 INP_WLOCK_ASSERT(inp); 888 889 /* Notify any offload devices of listener close */ 890 if (tp->t_state == TCPS_LISTEN) 891 tcp_offload_listen_close(tp); 892 in_pcbdrop(inp); 893 TCPSTAT_INC(tcps_closed); 894 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 895 so = inp->inp_socket; 896 soisdisconnected(so); 897 if (inp->inp_flags & INP_SOCKREF) { 898 KASSERT(so->so_state & SS_PROTOREF, 899 ("tcp_close: !SS_PROTOREF")); 900 inp->inp_flags &= ~INP_SOCKREF; 901 INP_WUNLOCK(inp); 902 ACCEPT_LOCK(); 903 SOCK_LOCK(so); 904 so->so_state &= ~SS_PROTOREF; 905 sofree(so); 906 return (NULL); 907 } 908 return (tp); 909 } 910 911 void 912 tcp_drain(void) 913 { 914 VNET_ITERATOR_DECL(vnet_iter); 915 916 if (!do_tcpdrain) 917 return; 918 919 VNET_LIST_RLOCK(); 920 VNET_FOREACH(vnet_iter) { 921 CURVNET_SET(vnet_iter); 922 INIT_VNET_INET(vnet_iter); 923 struct inpcb *inpb; 924 struct tcpcb *tcpb; 925 struct tseg_qent *te; 926 927 /* 928 * Walk the tcpbs, if existing, and flush the reassembly queue, 929 * if there is one... 930 * XXX: The "Net/3" implementation doesn't imply that the TCP 931 * reassembly queue should be flushed, but in a situation 932 * where we're really low on mbufs, this is potentially 933 * usefull. 934 */ 935 INP_INFO_RLOCK(&V_tcbinfo); 936 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) { 937 if (inpb->inp_flags & INP_TIMEWAIT) 938 continue; 939 INP_WLOCK(inpb); 940 if ((tcpb = intotcpcb(inpb)) != NULL) { 941 while ((te = LIST_FIRST(&tcpb->t_segq)) 942 != NULL) { 943 LIST_REMOVE(te, tqe_q); 944 m_freem(te->tqe_m); 945 uma_zfree(V_tcp_reass_zone, te); 946 tcpb->t_segqlen--; 947 V_tcp_reass_qsize--; 948 } 949 tcp_clean_sackreport(tcpb); 950 } 951 INP_WUNLOCK(inpb); 952 } 953 INP_INFO_RUNLOCK(&V_tcbinfo); 954 CURVNET_RESTORE(); 955 } 956 VNET_LIST_RUNLOCK(); 957 } 958 959 /* 960 * Notify a tcp user of an asynchronous error; 961 * store error as soft error, but wake up user 962 * (for now, won't do anything until can select for soft error). 963 * 964 * Do not wake up user since there currently is no mechanism for 965 * reporting soft errors (yet - a kqueue filter may be added). 966 */ 967 static struct inpcb * 968 tcp_notify(struct inpcb *inp, int error) 969 { 970 struct tcpcb *tp; 971 #ifdef INVARIANTS 972 INIT_VNET_INET(inp->inp_vnet); /* V_tcbinfo WLOCK ASSERT */ 973 #endif 974 975 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 976 INP_WLOCK_ASSERT(inp); 977 978 if ((inp->inp_flags & INP_TIMEWAIT) || 979 (inp->inp_flags & INP_DROPPED)) 980 return (inp); 981 982 tp = intotcpcb(inp); 983 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 984 985 /* 986 * Ignore some errors if we are hooked up. 987 * If connection hasn't completed, has retransmitted several times, 988 * and receives a second error, give up now. This is better 989 * than waiting a long time to establish a connection that 990 * can never complete. 991 */ 992 if (tp->t_state == TCPS_ESTABLISHED && 993 (error == EHOSTUNREACH || error == ENETUNREACH || 994 error == EHOSTDOWN)) { 995 return (inp); 996 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 997 tp->t_softerror) { 998 tp = tcp_drop(tp, error); 999 if (tp != NULL) 1000 return (inp); 1001 else 1002 return (NULL); 1003 } else { 1004 tp->t_softerror = error; 1005 return (inp); 1006 } 1007 #if 0 1008 wakeup( &so->so_timeo); 1009 sorwakeup(so); 1010 sowwakeup(so); 1011 #endif 1012 } 1013 1014 static int 1015 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1016 { 1017 INIT_VNET_INET(curvnet); 1018 int error, i, m, n, pcb_count; 1019 struct inpcb *inp, **inp_list; 1020 inp_gen_t gencnt; 1021 struct xinpgen xig; 1022 1023 /* 1024 * The process of preparing the TCB list is too time-consuming and 1025 * resource-intensive to repeat twice on every request. 1026 */ 1027 if (req->oldptr == NULL) { 1028 m = syncache_pcbcount(); 1029 n = V_tcbinfo.ipi_count; 1030 req->oldidx = 2 * (sizeof xig) 1031 + ((m + n) + n/8) * sizeof(struct xtcpcb); 1032 return (0); 1033 } 1034 1035 if (req->newptr != NULL) 1036 return (EPERM); 1037 1038 /* 1039 * OK, now we're committed to doing something. 1040 */ 1041 INP_INFO_RLOCK(&V_tcbinfo); 1042 gencnt = V_tcbinfo.ipi_gencnt; 1043 n = V_tcbinfo.ipi_count; 1044 INP_INFO_RUNLOCK(&V_tcbinfo); 1045 1046 m = syncache_pcbcount(); 1047 1048 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 1049 + (n + m) * sizeof(struct xtcpcb)); 1050 if (error != 0) 1051 return (error); 1052 1053 xig.xig_len = sizeof xig; 1054 xig.xig_count = n + m; 1055 xig.xig_gen = gencnt; 1056 xig.xig_sogen = so_gencnt; 1057 error = SYSCTL_OUT(req, &xig, sizeof xig); 1058 if (error) 1059 return (error); 1060 1061 error = syncache_pcblist(req, m, &pcb_count); 1062 if (error) 1063 return (error); 1064 1065 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 1066 if (inp_list == NULL) 1067 return (ENOMEM); 1068 1069 INP_INFO_RLOCK(&V_tcbinfo); 1070 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0; 1071 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) { 1072 INP_RLOCK(inp); 1073 if (inp->inp_gencnt <= gencnt) { 1074 /* 1075 * XXX: This use of cr_cansee(), introduced with 1076 * TCP state changes, is not quite right, but for 1077 * now, better than nothing. 1078 */ 1079 if (inp->inp_flags & INP_TIMEWAIT) { 1080 if (intotw(inp) != NULL) 1081 error = cr_cansee(req->td->td_ucred, 1082 intotw(inp)->tw_cred); 1083 else 1084 error = EINVAL; /* Skip this inp. */ 1085 } else 1086 error = cr_canseeinpcb(req->td->td_ucred, inp); 1087 if (error == 0) 1088 inp_list[i++] = inp; 1089 } 1090 INP_RUNLOCK(inp); 1091 } 1092 INP_INFO_RUNLOCK(&V_tcbinfo); 1093 n = i; 1094 1095 error = 0; 1096 for (i = 0; i < n; i++) { 1097 inp = inp_list[i]; 1098 INP_RLOCK(inp); 1099 if (inp->inp_gencnt <= gencnt) { 1100 struct xtcpcb xt; 1101 void *inp_ppcb; 1102 1103 bzero(&xt, sizeof(xt)); 1104 xt.xt_len = sizeof xt; 1105 /* XXX should avoid extra copy */ 1106 bcopy(inp, &xt.xt_inp, sizeof *inp); 1107 inp_ppcb = inp->inp_ppcb; 1108 if (inp_ppcb == NULL) 1109 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1110 else if (inp->inp_flags & INP_TIMEWAIT) { 1111 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1112 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1113 } else 1114 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1115 if (inp->inp_socket != NULL) 1116 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1117 else { 1118 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1119 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1120 } 1121 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1122 INP_RUNLOCK(inp); 1123 error = SYSCTL_OUT(req, &xt, sizeof xt); 1124 } else 1125 INP_RUNLOCK(inp); 1126 1127 } 1128 if (!error) { 1129 /* 1130 * Give the user an updated idea of our state. 1131 * If the generation differs from what we told 1132 * her before, she knows that something happened 1133 * while we were processing this request, and it 1134 * might be necessary to retry. 1135 */ 1136 INP_INFO_RLOCK(&V_tcbinfo); 1137 xig.xig_gen = V_tcbinfo.ipi_gencnt; 1138 xig.xig_sogen = so_gencnt; 1139 xig.xig_count = V_tcbinfo.ipi_count + pcb_count; 1140 INP_INFO_RUNLOCK(&V_tcbinfo); 1141 error = SYSCTL_OUT(req, &xig, sizeof xig); 1142 } 1143 free(inp_list, M_TEMP); 1144 return (error); 1145 } 1146 1147 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1148 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1149 1150 static int 1151 tcp_getcred(SYSCTL_HANDLER_ARGS) 1152 { 1153 INIT_VNET_INET(curvnet); 1154 struct xucred xuc; 1155 struct sockaddr_in addrs[2]; 1156 struct inpcb *inp; 1157 int error; 1158 1159 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1160 if (error) 1161 return (error); 1162 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1163 if (error) 1164 return (error); 1165 INP_INFO_RLOCK(&V_tcbinfo); 1166 inp = in_pcblookup_hash(&V_tcbinfo, addrs[1].sin_addr, 1167 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1168 if (inp != NULL) { 1169 INP_RLOCK(inp); 1170 INP_INFO_RUNLOCK(&V_tcbinfo); 1171 if (inp->inp_socket == NULL) 1172 error = ENOENT; 1173 if (error == 0) 1174 error = cr_canseeinpcb(req->td->td_ucred, inp); 1175 if (error == 0) 1176 cru2x(inp->inp_cred, &xuc); 1177 INP_RUNLOCK(inp); 1178 } else { 1179 INP_INFO_RUNLOCK(&V_tcbinfo); 1180 error = ENOENT; 1181 } 1182 if (error == 0) 1183 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1184 return (error); 1185 } 1186 1187 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1188 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1189 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1190 1191 #ifdef INET6 1192 static int 1193 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1194 { 1195 INIT_VNET_INET(curvnet); 1196 INIT_VNET_INET6(curvnet); 1197 struct xucred xuc; 1198 struct sockaddr_in6 addrs[2]; 1199 struct inpcb *inp; 1200 int error, mapped = 0; 1201 1202 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1203 if (error) 1204 return (error); 1205 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1206 if (error) 1207 return (error); 1208 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 || 1209 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) { 1210 return (error); 1211 } 1212 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1213 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1214 mapped = 1; 1215 else 1216 return (EINVAL); 1217 } 1218 1219 INP_INFO_RLOCK(&V_tcbinfo); 1220 if (mapped == 1) 1221 inp = in_pcblookup_hash(&V_tcbinfo, 1222 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1223 addrs[1].sin6_port, 1224 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1225 addrs[0].sin6_port, 1226 0, NULL); 1227 else 1228 inp = in6_pcblookup_hash(&V_tcbinfo, 1229 &addrs[1].sin6_addr, addrs[1].sin6_port, 1230 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1231 if (inp != NULL) { 1232 INP_RLOCK(inp); 1233 INP_INFO_RUNLOCK(&V_tcbinfo); 1234 if (inp->inp_socket == NULL) 1235 error = ENOENT; 1236 if (error == 0) 1237 error = cr_canseeinpcb(req->td->td_ucred, inp); 1238 if (error == 0) 1239 cru2x(inp->inp_cred, &xuc); 1240 INP_RUNLOCK(inp); 1241 } else { 1242 INP_INFO_RUNLOCK(&V_tcbinfo); 1243 error = ENOENT; 1244 } 1245 if (error == 0) 1246 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1247 return (error); 1248 } 1249 1250 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1251 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1252 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1253 #endif 1254 1255 1256 void 1257 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1258 { 1259 INIT_VNET_INET(curvnet); 1260 struct ip *ip = vip; 1261 struct tcphdr *th; 1262 struct in_addr faddr; 1263 struct inpcb *inp; 1264 struct tcpcb *tp; 1265 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1266 struct icmp *icp; 1267 struct in_conninfo inc; 1268 tcp_seq icmp_tcp_seq; 1269 int mtu; 1270 1271 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1272 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1273 return; 1274 1275 if (cmd == PRC_MSGSIZE) 1276 notify = tcp_mtudisc; 1277 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1278 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1279 notify = tcp_drop_syn_sent; 1280 /* 1281 * Redirects don't need to be handled up here. 1282 */ 1283 else if (PRC_IS_REDIRECT(cmd)) 1284 return; 1285 /* 1286 * Source quench is depreciated. 1287 */ 1288 else if (cmd == PRC_QUENCH) 1289 return; 1290 /* 1291 * Hostdead is ugly because it goes linearly through all PCBs. 1292 * XXX: We never get this from ICMP, otherwise it makes an 1293 * excellent DoS attack on machines with many connections. 1294 */ 1295 else if (cmd == PRC_HOSTDEAD) 1296 ip = NULL; 1297 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1298 return; 1299 if (ip != NULL) { 1300 icp = (struct icmp *)((caddr_t)ip 1301 - offsetof(struct icmp, icmp_ip)); 1302 th = (struct tcphdr *)((caddr_t)ip 1303 + (ip->ip_hl << 2)); 1304 INP_INFO_WLOCK(&V_tcbinfo); 1305 inp = in_pcblookup_hash(&V_tcbinfo, faddr, th->th_dport, 1306 ip->ip_src, th->th_sport, 0, NULL); 1307 if (inp != NULL) { 1308 INP_WLOCK(inp); 1309 if (!(inp->inp_flags & INP_TIMEWAIT) && 1310 !(inp->inp_flags & INP_DROPPED) && 1311 !(inp->inp_socket == NULL)) { 1312 icmp_tcp_seq = htonl(th->th_seq); 1313 tp = intotcpcb(inp); 1314 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1315 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1316 if (cmd == PRC_MSGSIZE) { 1317 /* 1318 * MTU discovery: 1319 * If we got a needfrag set the MTU 1320 * in the route to the suggested new 1321 * value (if given) and then notify. 1322 */ 1323 bzero(&inc, sizeof(inc)); 1324 inc.inc_faddr = faddr; 1325 inc.inc_fibnum = 1326 inp->inp_inc.inc_fibnum; 1327 1328 mtu = ntohs(icp->icmp_nextmtu); 1329 /* 1330 * If no alternative MTU was 1331 * proposed, try the next smaller 1332 * one. ip->ip_len has already 1333 * been swapped in icmp_input(). 1334 */ 1335 if (!mtu) 1336 mtu = ip_next_mtu(ip->ip_len, 1337 1); 1338 if (mtu < max(296, V_tcp_minmss 1339 + sizeof(struct tcpiphdr))) 1340 mtu = 0; 1341 if (!mtu) 1342 mtu = V_tcp_mssdflt 1343 + sizeof(struct tcpiphdr); 1344 /* 1345 * Only cache the the MTU if it 1346 * is smaller than the interface 1347 * or route MTU. tcp_mtudisc() 1348 * will do right thing by itself. 1349 */ 1350 if (mtu <= tcp_maxmtu(&inc, NULL)) 1351 tcp_hc_updatemtu(&inc, mtu); 1352 } 1353 1354 inp = (*notify)(inp, inetctlerrmap[cmd]); 1355 } 1356 } 1357 if (inp != NULL) 1358 INP_WUNLOCK(inp); 1359 } else { 1360 bzero(&inc, sizeof(inc)); 1361 inc.inc_fport = th->th_dport; 1362 inc.inc_lport = th->th_sport; 1363 inc.inc_faddr = faddr; 1364 inc.inc_laddr = ip->ip_src; 1365 syncache_unreach(&inc, th); 1366 } 1367 INP_INFO_WUNLOCK(&V_tcbinfo); 1368 } else 1369 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify); 1370 } 1371 1372 #ifdef INET6 1373 void 1374 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1375 { 1376 INIT_VNET_INET(curvnet); 1377 struct tcphdr th; 1378 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1379 struct ip6_hdr *ip6; 1380 struct mbuf *m; 1381 struct ip6ctlparam *ip6cp = NULL; 1382 const struct sockaddr_in6 *sa6_src = NULL; 1383 int off; 1384 struct tcp_portonly { 1385 u_int16_t th_sport; 1386 u_int16_t th_dport; 1387 } *thp; 1388 1389 if (sa->sa_family != AF_INET6 || 1390 sa->sa_len != sizeof(struct sockaddr_in6)) 1391 return; 1392 1393 if (cmd == PRC_MSGSIZE) 1394 notify = tcp_mtudisc; 1395 else if (!PRC_IS_REDIRECT(cmd) && 1396 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1397 return; 1398 /* Source quench is depreciated. */ 1399 else if (cmd == PRC_QUENCH) 1400 return; 1401 1402 /* if the parameter is from icmp6, decode it. */ 1403 if (d != NULL) { 1404 ip6cp = (struct ip6ctlparam *)d; 1405 m = ip6cp->ip6c_m; 1406 ip6 = ip6cp->ip6c_ip6; 1407 off = ip6cp->ip6c_off; 1408 sa6_src = ip6cp->ip6c_src; 1409 } else { 1410 m = NULL; 1411 ip6 = NULL; 1412 off = 0; /* fool gcc */ 1413 sa6_src = &sa6_any; 1414 } 1415 1416 if (ip6 != NULL) { 1417 struct in_conninfo inc; 1418 /* 1419 * XXX: We assume that when IPV6 is non NULL, 1420 * M and OFF are valid. 1421 */ 1422 1423 /* check if we can safely examine src and dst ports */ 1424 if (m->m_pkthdr.len < off + sizeof(*thp)) 1425 return; 1426 1427 bzero(&th, sizeof(th)); 1428 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1429 1430 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport, 1431 (struct sockaddr *)ip6cp->ip6c_src, 1432 th.th_sport, cmd, NULL, notify); 1433 1434 bzero(&inc, sizeof(inc)); 1435 inc.inc_fport = th.th_dport; 1436 inc.inc_lport = th.th_sport; 1437 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1438 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1439 inc.inc_flags |= INC_ISIPV6; 1440 INP_INFO_WLOCK(&V_tcbinfo); 1441 syncache_unreach(&inc, &th); 1442 INP_INFO_WUNLOCK(&V_tcbinfo); 1443 } else 1444 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1445 0, cmd, NULL, notify); 1446 } 1447 #endif /* INET6 */ 1448 1449 1450 /* 1451 * Following is where TCP initial sequence number generation occurs. 1452 * 1453 * There are two places where we must use initial sequence numbers: 1454 * 1. In SYN-ACK packets. 1455 * 2. In SYN packets. 1456 * 1457 * All ISNs for SYN-ACK packets are generated by the syncache. See 1458 * tcp_syncache.c for details. 1459 * 1460 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1461 * depends on this property. In addition, these ISNs should be 1462 * unguessable so as to prevent connection hijacking. To satisfy 1463 * the requirements of this situation, the algorithm outlined in 1464 * RFC 1948 is used, with only small modifications. 1465 * 1466 * Implementation details: 1467 * 1468 * Time is based off the system timer, and is corrected so that it 1469 * increases by one megabyte per second. This allows for proper 1470 * recycling on high speed LANs while still leaving over an hour 1471 * before rollover. 1472 * 1473 * As reading the *exact* system time is too expensive to be done 1474 * whenever setting up a TCP connection, we increment the time 1475 * offset in two ways. First, a small random positive increment 1476 * is added to isn_offset for each connection that is set up. 1477 * Second, the function tcp_isn_tick fires once per clock tick 1478 * and increments isn_offset as necessary so that sequence numbers 1479 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1480 * random positive increments serve only to ensure that the same 1481 * exact sequence number is never sent out twice (as could otherwise 1482 * happen when a port is recycled in less than the system tick 1483 * interval.) 1484 * 1485 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1486 * between seeding of isn_secret. This is normally set to zero, 1487 * as reseeding should not be necessary. 1488 * 1489 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1490 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1491 * general, this means holding an exclusive (write) lock. 1492 */ 1493 1494 #define ISN_BYTES_PER_SECOND 1048576 1495 #define ISN_STATIC_INCREMENT 4096 1496 #define ISN_RANDOM_INCREMENT (4096 - 1) 1497 1498 #ifdef VIMAGE_GLOBALS 1499 static u_char isn_secret[32]; 1500 static int isn_last_reseed; 1501 static u_int32_t isn_offset, isn_offset_old; 1502 #endif 1503 1504 tcp_seq 1505 tcp_new_isn(struct tcpcb *tp) 1506 { 1507 INIT_VNET_INET(tp->t_vnet); 1508 MD5_CTX isn_ctx; 1509 u_int32_t md5_buffer[4]; 1510 tcp_seq new_isn; 1511 1512 INP_WLOCK_ASSERT(tp->t_inpcb); 1513 1514 ISN_LOCK(); 1515 /* Seed if this is the first use, reseed if requested. */ 1516 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) && 1517 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz) 1518 < (u_int)ticks))) { 1519 read_random(&V_isn_secret, sizeof(V_isn_secret)); 1520 V_isn_last_reseed = ticks; 1521 } 1522 1523 /* Compute the md5 hash and return the ISN. */ 1524 MD5Init(&isn_ctx); 1525 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1526 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1527 #ifdef INET6 1528 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1529 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1530 sizeof(struct in6_addr)); 1531 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1532 sizeof(struct in6_addr)); 1533 } else 1534 #endif 1535 { 1536 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1537 sizeof(struct in_addr)); 1538 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1539 sizeof(struct in_addr)); 1540 } 1541 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret)); 1542 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1543 new_isn = (tcp_seq) md5_buffer[0]; 1544 V_isn_offset += ISN_STATIC_INCREMENT + 1545 (arc4random() & ISN_RANDOM_INCREMENT); 1546 new_isn += V_isn_offset; 1547 ISN_UNLOCK(); 1548 return (new_isn); 1549 } 1550 1551 /* 1552 * Increment the offset to the next ISN_BYTES_PER_SECOND / 100 boundary 1553 * to keep time flowing at a relatively constant rate. If the random 1554 * increments have already pushed us past the projected offset, do nothing. 1555 */ 1556 static void 1557 tcp_isn_tick(void *xtp) 1558 { 1559 VNET_ITERATOR_DECL(vnet_iter); 1560 u_int32_t projected_offset; 1561 1562 VNET_LIST_RLOCK(); 1563 ISN_LOCK(); 1564 VNET_FOREACH(vnet_iter) { 1565 CURVNET_SET(vnet_iter); /* XXX appease INVARIANTS */ 1566 INIT_VNET_INET(curvnet); 1567 projected_offset = 1568 V_isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1569 1570 if (SEQ_GT(projected_offset, V_isn_offset)) 1571 V_isn_offset = projected_offset; 1572 1573 V_isn_offset_old = V_isn_offset; 1574 CURVNET_RESTORE(); 1575 } 1576 ISN_UNLOCK(); 1577 VNET_LIST_RUNLOCK(); 1578 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1579 } 1580 1581 /* 1582 * When a specific ICMP unreachable message is received and the 1583 * connection state is SYN-SENT, drop the connection. This behavior 1584 * is controlled by the icmp_may_rst sysctl. 1585 */ 1586 struct inpcb * 1587 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1588 { 1589 #ifdef INVARIANTS 1590 INIT_VNET_INET(inp->inp_vnet); 1591 #endif 1592 struct tcpcb *tp; 1593 1594 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 1595 INP_WLOCK_ASSERT(inp); 1596 1597 if ((inp->inp_flags & INP_TIMEWAIT) || 1598 (inp->inp_flags & INP_DROPPED)) 1599 return (inp); 1600 1601 tp = intotcpcb(inp); 1602 if (tp->t_state != TCPS_SYN_SENT) 1603 return (inp); 1604 1605 tp = tcp_drop(tp, errno); 1606 if (tp != NULL) 1607 return (inp); 1608 else 1609 return (NULL); 1610 } 1611 1612 /* 1613 * When `need fragmentation' ICMP is received, update our idea of the MSS 1614 * based on the new value in the route. Also nudge TCP to send something, 1615 * since we know the packet we just sent was dropped. 1616 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1617 */ 1618 struct inpcb * 1619 tcp_mtudisc(struct inpcb *inp, int errno) 1620 { 1621 INIT_VNET_INET(inp->inp_vnet); 1622 struct tcpcb *tp; 1623 struct socket *so; 1624 1625 INP_WLOCK_ASSERT(inp); 1626 if ((inp->inp_flags & INP_TIMEWAIT) || 1627 (inp->inp_flags & INP_DROPPED)) 1628 return (inp); 1629 1630 tp = intotcpcb(inp); 1631 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1632 1633 tcp_mss_update(tp, -1, NULL, NULL); 1634 1635 so = inp->inp_socket; 1636 SOCKBUF_LOCK(&so->so_snd); 1637 /* If the mss is larger than the socket buffer, decrease the mss. */ 1638 if (so->so_snd.sb_hiwat < tp->t_maxseg) 1639 tp->t_maxseg = so->so_snd.sb_hiwat; 1640 SOCKBUF_UNLOCK(&so->so_snd); 1641 1642 TCPSTAT_INC(tcps_mturesent); 1643 tp->t_rtttime = 0; 1644 tp->snd_nxt = tp->snd_una; 1645 tcp_free_sackholes(tp); 1646 tp->snd_recover = tp->snd_max; 1647 if (tp->t_flags & TF_SACK_PERMIT) 1648 EXIT_FASTRECOVERY(tp); 1649 tcp_output_send(tp); 1650 return (inp); 1651 } 1652 1653 /* 1654 * Look-up the routing entry to the peer of this inpcb. If no route 1655 * is found and it cannot be allocated, then return 0. This routine 1656 * is called by TCP routines that access the rmx structure and by 1657 * tcp_mss_update to get the peer/interface MTU. 1658 */ 1659 u_long 1660 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1661 { 1662 struct route sro; 1663 struct sockaddr_in *dst; 1664 struct ifnet *ifp; 1665 u_long maxmtu = 0; 1666 1667 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1668 1669 bzero(&sro, sizeof(sro)); 1670 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1671 dst = (struct sockaddr_in *)&sro.ro_dst; 1672 dst->sin_family = AF_INET; 1673 dst->sin_len = sizeof(*dst); 1674 dst->sin_addr = inc->inc_faddr; 1675 in_rtalloc_ign(&sro, 0, inc->inc_fibnum); 1676 } 1677 if (sro.ro_rt != NULL) { 1678 ifp = sro.ro_rt->rt_ifp; 1679 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1680 maxmtu = ifp->if_mtu; 1681 else 1682 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1683 1684 /* Report additional interface capabilities. */ 1685 if (flags != NULL) { 1686 if (ifp->if_capenable & IFCAP_TSO4 && 1687 ifp->if_hwassist & CSUM_TSO) 1688 *flags |= CSUM_TSO; 1689 } 1690 RTFREE(sro.ro_rt); 1691 } 1692 return (maxmtu); 1693 } 1694 1695 #ifdef INET6 1696 u_long 1697 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1698 { 1699 struct route_in6 sro6; 1700 struct ifnet *ifp; 1701 u_long maxmtu = 0; 1702 1703 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1704 1705 bzero(&sro6, sizeof(sro6)); 1706 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1707 sro6.ro_dst.sin6_family = AF_INET6; 1708 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1709 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1710 rtalloc_ign((struct route *)&sro6, 0); 1711 } 1712 if (sro6.ro_rt != NULL) { 1713 ifp = sro6.ro_rt->rt_ifp; 1714 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1715 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1716 else 1717 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1718 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1719 1720 /* Report additional interface capabilities. */ 1721 if (flags != NULL) { 1722 if (ifp->if_capenable & IFCAP_TSO6 && 1723 ifp->if_hwassist & CSUM_TSO) 1724 *flags |= CSUM_TSO; 1725 } 1726 RTFREE(sro6.ro_rt); 1727 } 1728 1729 return (maxmtu); 1730 } 1731 #endif /* INET6 */ 1732 1733 #ifdef IPSEC 1734 /* compute ESP/AH header size for TCP, including outer IP header. */ 1735 size_t 1736 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1737 { 1738 struct inpcb *inp; 1739 struct mbuf *m; 1740 size_t hdrsiz; 1741 struct ip *ip; 1742 #ifdef INET6 1743 struct ip6_hdr *ip6; 1744 #endif 1745 struct tcphdr *th; 1746 1747 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1748 return (0); 1749 MGETHDR(m, M_DONTWAIT, MT_DATA); 1750 if (!m) 1751 return (0); 1752 1753 #ifdef INET6 1754 if ((inp->inp_vflag & INP_IPV6) != 0) { 1755 ip6 = mtod(m, struct ip6_hdr *); 1756 th = (struct tcphdr *)(ip6 + 1); 1757 m->m_pkthdr.len = m->m_len = 1758 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1759 tcpip_fillheaders(inp, ip6, th); 1760 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1761 } else 1762 #endif /* INET6 */ 1763 { 1764 ip = mtod(m, struct ip *); 1765 th = (struct tcphdr *)(ip + 1); 1766 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1767 tcpip_fillheaders(inp, ip, th); 1768 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1769 } 1770 1771 m_free(m); 1772 return (hdrsiz); 1773 } 1774 #endif /* IPSEC */ 1775 1776 /* 1777 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1778 * 1779 * This code attempts to calculate the bandwidth-delay product as a 1780 * means of determining the optimal window size to maximize bandwidth, 1781 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1782 * routers. This code also does a fairly good job keeping RTTs in check 1783 * across slow links like modems. We implement an algorithm which is very 1784 * similar (but not meant to be) TCP/Vegas. The code operates on the 1785 * transmitter side of a TCP connection and so only effects the transmit 1786 * side of the connection. 1787 * 1788 * BACKGROUND: TCP makes no provision for the management of buffer space 1789 * at the end points or at the intermediate routers and switches. A TCP 1790 * stream, whether using NewReno or not, will eventually buffer as 1791 * many packets as it is able and the only reason this typically works is 1792 * due to the fairly small default buffers made available for a connection 1793 * (typicaly 16K or 32K). As machines use larger windows and/or window 1794 * scaling it is now fairly easy for even a single TCP connection to blow-out 1795 * all available buffer space not only on the local interface, but on 1796 * intermediate routers and switches as well. NewReno makes a misguided 1797 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1798 * then backing off, then steadily increasing the window again until another 1799 * failure occurs, ad-infinitum. This results in terrible oscillation that 1800 * is only made worse as network loads increase and the idea of intentionally 1801 * blowing out network buffers is, frankly, a terrible way to manage network 1802 * resources. 1803 * 1804 * It is far better to limit the transmit window prior to the failure 1805 * condition being achieved. There are two general ways to do this: First 1806 * you can 'scan' through different transmit window sizes and locate the 1807 * point where the RTT stops increasing, indicating that you have filled the 1808 * pipe, then scan backwards until you note that RTT stops decreasing, then 1809 * repeat ad-infinitum. This method works in principle but has severe 1810 * implementation issues due to RTT variances, timer granularity, and 1811 * instability in the algorithm which can lead to many false positives and 1812 * create oscillations as well as interact badly with other TCP streams 1813 * implementing the same algorithm. 1814 * 1815 * The second method is to limit the window to the bandwidth delay product 1816 * of the link. This is the method we implement. RTT variances and our 1817 * own manipulation of the congestion window, bwnd, can potentially 1818 * destabilize the algorithm. For this reason we have to stabilize the 1819 * elements used to calculate the window. We do this by using the minimum 1820 * observed RTT, the long term average of the observed bandwidth, and 1821 * by adding two segments worth of slop. It isn't perfect but it is able 1822 * to react to changing conditions and gives us a very stable basis on 1823 * which to extend the algorithm. 1824 */ 1825 void 1826 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1827 { 1828 INIT_VNET_INET(tp->t_vnet); 1829 u_long bw; 1830 u_long bwnd; 1831 int save_ticks; 1832 1833 INP_WLOCK_ASSERT(tp->t_inpcb); 1834 1835 /* 1836 * If inflight_enable is disabled in the middle of a tcp connection, 1837 * make sure snd_bwnd is effectively disabled. 1838 */ 1839 if (V_tcp_inflight_enable == 0 || 1840 tp->t_rttlow < V_tcp_inflight_rttthresh) { 1841 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1842 tp->snd_bandwidth = 0; 1843 return; 1844 } 1845 1846 /* 1847 * Figure out the bandwidth. Due to the tick granularity this 1848 * is a very rough number and it MUST be averaged over a fairly 1849 * long period of time. XXX we need to take into account a link 1850 * that is not using all available bandwidth, but for now our 1851 * slop will ramp us up if this case occurs and the bandwidth later 1852 * increases. 1853 * 1854 * Note: if ticks rollover 'bw' may wind up negative. We must 1855 * effectively reset t_bw_rtttime for this case. 1856 */ 1857 save_ticks = ticks; 1858 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 1859 return; 1860 1861 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 1862 (save_ticks - tp->t_bw_rtttime); 1863 tp->t_bw_rtttime = save_ticks; 1864 tp->t_bw_rtseq = ack_seq; 1865 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 1866 return; 1867 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1868 1869 tp->snd_bandwidth = bw; 1870 1871 /* 1872 * Calculate the semi-static bandwidth delay product, plus two maximal 1873 * segments. The additional slop puts us squarely in the sweet 1874 * spot and also handles the bandwidth run-up case and stabilization. 1875 * Without the slop we could be locking ourselves into a lower 1876 * bandwidth. 1877 * 1878 * Situations Handled: 1879 * (1) Prevents over-queueing of packets on LANs, especially on 1880 * high speed LANs, allowing larger TCP buffers to be 1881 * specified, and also does a good job preventing 1882 * over-queueing of packets over choke points like modems 1883 * (at least for the transmit side). 1884 * 1885 * (2) Is able to handle changing network loads (bandwidth 1886 * drops so bwnd drops, bandwidth increases so bwnd 1887 * increases). 1888 * 1889 * (3) Theoretically should stabilize in the face of multiple 1890 * connections implementing the same algorithm (this may need 1891 * a little work). 1892 * 1893 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1894 * be adjusted with a sysctl but typically only needs to be 1895 * on very slow connections. A value no smaller then 5 1896 * should be used, but only reduce this default if you have 1897 * no other choice. 1898 */ 1899 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1900 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + V_tcp_inflight_stab * tp->t_maxseg / 10; 1901 #undef USERTT 1902 1903 if (tcp_inflight_debug > 0) { 1904 static int ltime; 1905 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1906 ltime = ticks; 1907 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1908 tp, 1909 bw, 1910 tp->t_rttbest, 1911 tp->t_srtt, 1912 bwnd 1913 ); 1914 } 1915 } 1916 if ((long)bwnd < V_tcp_inflight_min) 1917 bwnd = V_tcp_inflight_min; 1918 if (bwnd > V_tcp_inflight_max) 1919 bwnd = V_tcp_inflight_max; 1920 if ((long)bwnd < tp->t_maxseg * 2) 1921 bwnd = tp->t_maxseg * 2; 1922 tp->snd_bwnd = bwnd; 1923 } 1924 1925 #ifdef TCP_SIGNATURE 1926 /* 1927 * Callback function invoked by m_apply() to digest TCP segment data 1928 * contained within an mbuf chain. 1929 */ 1930 static int 1931 tcp_signature_apply(void *fstate, void *data, u_int len) 1932 { 1933 1934 MD5Update(fstate, (u_char *)data, len); 1935 return (0); 1936 } 1937 1938 /* 1939 * Compute TCP-MD5 hash of a TCP segment. (RFC2385) 1940 * 1941 * Parameters: 1942 * m pointer to head of mbuf chain 1943 * _unused 1944 * len length of TCP segment data, excluding options 1945 * optlen length of TCP segment options 1946 * buf pointer to storage for computed MD5 digest 1947 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 1948 * 1949 * We do this over ip, tcphdr, segment data, and the key in the SADB. 1950 * When called from tcp_input(), we can be sure that th_sum has been 1951 * zeroed out and verified already. 1952 * 1953 * Return 0 if successful, otherwise return -1. 1954 * 1955 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 1956 * search with the destination IP address, and a 'magic SPI' to be 1957 * determined by the application. This is hardcoded elsewhere to 1179 1958 * right now. Another branch of this code exists which uses the SPD to 1959 * specify per-application flows but it is unstable. 1960 */ 1961 int 1962 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen, 1963 u_char *buf, u_int direction) 1964 { 1965 INIT_VNET_IPSEC(curvnet); 1966 union sockaddr_union dst; 1967 struct ippseudo ippseudo; 1968 MD5_CTX ctx; 1969 int doff; 1970 struct ip *ip; 1971 struct ipovly *ipovly; 1972 struct secasvar *sav; 1973 struct tcphdr *th; 1974 #ifdef INET6 1975 struct ip6_hdr *ip6; 1976 struct in6_addr in6; 1977 char ip6buf[INET6_ADDRSTRLEN]; 1978 uint32_t plen; 1979 uint16_t nhdr; 1980 #endif 1981 u_short savecsum; 1982 1983 KASSERT(m != NULL, ("NULL mbuf chain")); 1984 KASSERT(buf != NULL, ("NULL signature pointer")); 1985 1986 /* Extract the destination from the IP header in the mbuf. */ 1987 bzero(&dst, sizeof(union sockaddr_union)); 1988 ip = mtod(m, struct ip *); 1989 #ifdef INET6 1990 ip6 = NULL; /* Make the compiler happy. */ 1991 #endif 1992 switch (ip->ip_v) { 1993 case IPVERSION: 1994 dst.sa.sa_len = sizeof(struct sockaddr_in); 1995 dst.sa.sa_family = AF_INET; 1996 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 1997 ip->ip_src : ip->ip_dst; 1998 break; 1999 #ifdef INET6 2000 case (IPV6_VERSION >> 4): 2001 ip6 = mtod(m, struct ip6_hdr *); 2002 dst.sa.sa_len = sizeof(struct sockaddr_in6); 2003 dst.sa.sa_family = AF_INET6; 2004 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ? 2005 ip6->ip6_src : ip6->ip6_dst; 2006 break; 2007 #endif 2008 default: 2009 return (EINVAL); 2010 /* NOTREACHED */ 2011 break; 2012 } 2013 2014 /* Look up an SADB entry which matches the address of the peer. */ 2015 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2016 if (sav == NULL) { 2017 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__, 2018 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) : 2019 #ifdef INET6 2020 (ip->ip_v == (IPV6_VERSION >> 4)) ? 2021 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) : 2022 #endif 2023 "(unsupported)")); 2024 return (EINVAL); 2025 } 2026 2027 MD5Init(&ctx); 2028 /* 2029 * Step 1: Update MD5 hash with IP(v6) pseudo-header. 2030 * 2031 * XXX The ippseudo header MUST be digested in network byte order, 2032 * or else we'll fail the regression test. Assume all fields we've 2033 * been doing arithmetic on have been in host byte order. 2034 * XXX One cannot depend on ipovly->ih_len here. When called from 2035 * tcp_output(), the underlying ip_len member has not yet been set. 2036 */ 2037 switch (ip->ip_v) { 2038 case IPVERSION: 2039 ipovly = (struct ipovly *)ip; 2040 ippseudo.ippseudo_src = ipovly->ih_src; 2041 ippseudo.ippseudo_dst = ipovly->ih_dst; 2042 ippseudo.ippseudo_pad = 0; 2043 ippseudo.ippseudo_p = IPPROTO_TCP; 2044 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + 2045 optlen); 2046 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2047 2048 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip)); 2049 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen; 2050 break; 2051 #ifdef INET6 2052 /* 2053 * RFC 2385, 2.0 Proposal 2054 * For IPv6, the pseudo-header is as described in RFC 2460, namely the 2055 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero- 2056 * extended next header value (to form 32 bits), and 32-bit segment 2057 * length. 2058 * Note: Upper-Layer Packet Length comes before Next Header. 2059 */ 2060 case (IPV6_VERSION >> 4): 2061 in6 = ip6->ip6_src; 2062 in6_clearscope(&in6); 2063 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2064 in6 = ip6->ip6_dst; 2065 in6_clearscope(&in6); 2066 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2067 plen = htonl(len + sizeof(struct tcphdr) + optlen); 2068 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t)); 2069 nhdr = 0; 2070 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2071 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2072 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2073 nhdr = IPPROTO_TCP; 2074 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2075 2076 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr)); 2077 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen; 2078 break; 2079 #endif 2080 default: 2081 return (EINVAL); 2082 /* NOTREACHED */ 2083 break; 2084 } 2085 2086 2087 /* 2088 * Step 2: Update MD5 hash with TCP header, excluding options. 2089 * The TCP checksum must be set to zero. 2090 */ 2091 savecsum = th->th_sum; 2092 th->th_sum = 0; 2093 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2094 th->th_sum = savecsum; 2095 2096 /* 2097 * Step 3: Update MD5 hash with TCP segment data. 2098 * Use m_apply() to avoid an early m_pullup(). 2099 */ 2100 if (len > 0) 2101 m_apply(m, doff, len, tcp_signature_apply, &ctx); 2102 2103 /* 2104 * Step 4: Update MD5 hash with shared secret. 2105 */ 2106 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 2107 MD5Final(buf, &ctx); 2108 2109 key_sa_recordxfer(sav, m); 2110 KEY_FREESAV(&sav); 2111 return (0); 2112 } 2113 #endif /* TCP_SIGNATURE */ 2114 2115 static int 2116 sysctl_drop(SYSCTL_HANDLER_ARGS) 2117 { 2118 INIT_VNET_INET(curvnet); 2119 #ifdef INET6 2120 INIT_VNET_INET6(curvnet); 2121 #endif 2122 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 2123 struct sockaddr_storage addrs[2]; 2124 struct inpcb *inp; 2125 struct tcpcb *tp; 2126 struct tcptw *tw; 2127 struct sockaddr_in *fin, *lin; 2128 #ifdef INET6 2129 struct sockaddr_in6 *fin6, *lin6; 2130 #endif 2131 int error; 2132 2133 inp = NULL; 2134 fin = lin = NULL; 2135 #ifdef INET6 2136 fin6 = lin6 = NULL; 2137 #endif 2138 error = 0; 2139 2140 if (req->oldptr != NULL || req->oldlen != 0) 2141 return (EINVAL); 2142 if (req->newptr == NULL) 2143 return (EPERM); 2144 if (req->newlen < sizeof(addrs)) 2145 return (ENOMEM); 2146 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2147 if (error) 2148 return (error); 2149 2150 switch (addrs[0].ss_family) { 2151 #ifdef INET6 2152 case AF_INET6: 2153 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2154 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2155 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2156 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2157 return (EINVAL); 2158 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2159 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2160 return (EINVAL); 2161 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2162 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2163 fin = (struct sockaddr_in *)&addrs[0]; 2164 lin = (struct sockaddr_in *)&addrs[1]; 2165 break; 2166 } 2167 error = sa6_embedscope(fin6, V_ip6_use_defzone); 2168 if (error) 2169 return (error); 2170 error = sa6_embedscope(lin6, V_ip6_use_defzone); 2171 if (error) 2172 return (error); 2173 break; 2174 #endif 2175 case AF_INET: 2176 fin = (struct sockaddr_in *)&addrs[0]; 2177 lin = (struct sockaddr_in *)&addrs[1]; 2178 if (fin->sin_len != sizeof(struct sockaddr_in) || 2179 lin->sin_len != sizeof(struct sockaddr_in)) 2180 return (EINVAL); 2181 break; 2182 default: 2183 return (EINVAL); 2184 } 2185 INP_INFO_WLOCK(&V_tcbinfo); 2186 switch (addrs[0].ss_family) { 2187 #ifdef INET6 2188 case AF_INET6: 2189 inp = in6_pcblookup_hash(&V_tcbinfo, &fin6->sin6_addr, 2190 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port, 0, 2191 NULL); 2192 break; 2193 #endif 2194 case AF_INET: 2195 inp = in_pcblookup_hash(&V_tcbinfo, fin->sin_addr, 2196 fin->sin_port, lin->sin_addr, lin->sin_port, 0, NULL); 2197 break; 2198 } 2199 if (inp != NULL) { 2200 INP_WLOCK(inp); 2201 if (inp->inp_flags & INP_TIMEWAIT) { 2202 /* 2203 * XXXRW: There currently exists a state where an 2204 * inpcb is present, but its timewait state has been 2205 * discarded. For now, don't allow dropping of this 2206 * type of inpcb. 2207 */ 2208 tw = intotw(inp); 2209 if (tw != NULL) 2210 tcp_twclose(tw, 0); 2211 else 2212 INP_WUNLOCK(inp); 2213 } else if (!(inp->inp_flags & INP_DROPPED) && 2214 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2215 tp = intotcpcb(inp); 2216 tp = tcp_drop(tp, ECONNABORTED); 2217 if (tp != NULL) 2218 INP_WUNLOCK(inp); 2219 } else 2220 INP_WUNLOCK(inp); 2221 } else 2222 error = ESRCH; 2223 INP_INFO_WUNLOCK(&V_tcbinfo); 2224 return (error); 2225 } 2226 2227 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2228 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2229 0, sysctl_drop, "", "Drop TCP connection"); 2230 2231 /* 2232 * Generate a standardized TCP log line for use throughout the 2233 * tcp subsystem. Memory allocation is done with M_NOWAIT to 2234 * allow use in the interrupt context. 2235 * 2236 * NB: The caller MUST free(s, M_TCPLOG) the returned string. 2237 * NB: The function may return NULL if memory allocation failed. 2238 * 2239 * Due to header inclusion and ordering limitations the struct ip 2240 * and ip6_hdr pointers have to be passed as void pointers. 2241 */ 2242 char * 2243 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2244 const void *ip6hdr) 2245 { 2246 char *s, *sp; 2247 size_t size; 2248 struct ip *ip; 2249 #ifdef INET6 2250 const struct ip6_hdr *ip6; 2251 2252 ip6 = (const struct ip6_hdr *)ip6hdr; 2253 #endif /* INET6 */ 2254 ip = (struct ip *)ip4hdr; 2255 2256 /* 2257 * The log line looks like this: 2258 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>" 2259 */ 2260 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") + 2261 sizeof(PRINT_TH_FLAGS) + 1 + 2262 #ifdef INET6 2263 2 * INET6_ADDRSTRLEN; 2264 #else 2265 2 * INET_ADDRSTRLEN; 2266 #endif /* INET6 */ 2267 2268 /* Is logging enabled? */ 2269 if (tcp_log_debug == 0 && tcp_log_in_vain == 0) 2270 return (NULL); 2271 2272 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT); 2273 if (s == NULL) 2274 return (NULL); 2275 2276 strcat(s, "TCP: ["); 2277 sp = s + strlen(s); 2278 2279 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) { 2280 inet_ntoa_r(inc->inc_faddr, sp); 2281 sp = s + strlen(s); 2282 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2283 sp = s + strlen(s); 2284 inet_ntoa_r(inc->inc_laddr, sp); 2285 sp = s + strlen(s); 2286 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2287 #ifdef INET6 2288 } else if (inc) { 2289 ip6_sprintf(sp, &inc->inc6_faddr); 2290 sp = s + strlen(s); 2291 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2292 sp = s + strlen(s); 2293 ip6_sprintf(sp, &inc->inc6_laddr); 2294 sp = s + strlen(s); 2295 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2296 } else if (ip6 && th) { 2297 ip6_sprintf(sp, &ip6->ip6_src); 2298 sp = s + strlen(s); 2299 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2300 sp = s + strlen(s); 2301 ip6_sprintf(sp, &ip6->ip6_dst); 2302 sp = s + strlen(s); 2303 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2304 #endif /* INET6 */ 2305 } else if (ip && th) { 2306 inet_ntoa_r(ip->ip_src, sp); 2307 sp = s + strlen(s); 2308 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2309 sp = s + strlen(s); 2310 inet_ntoa_r(ip->ip_dst, sp); 2311 sp = s + strlen(s); 2312 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2313 } else { 2314 free(s, M_TCPLOG); 2315 return (NULL); 2316 } 2317 sp = s + strlen(s); 2318 if (th) 2319 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS); 2320 if (*(s + size - 1) != '\0') 2321 panic("%s: string too long", __func__); 2322 return (s); 2323 } 2324