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