1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_compat.h" 36 #include "opt_inet.h" 37 #include "opt_inet6.h" 38 #include "opt_ipsec.h" 39 #include "opt_tcpdebug.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/callout.h> 44 #include <sys/hhook.h> 45 #include <sys/kernel.h> 46 #include <sys/khelp.h> 47 #include <sys/sysctl.h> 48 #include <sys/jail.h> 49 #include <sys/malloc.h> 50 #include <sys/mbuf.h> 51 #ifdef INET6 52 #include <sys/domain.h> 53 #endif 54 #include <sys/priv.h> 55 #include <sys/proc.h> 56 #include <sys/socket.h> 57 #include <sys/socketvar.h> 58 #include <sys/protosw.h> 59 #include <sys/random.h> 60 61 #include <vm/uma.h> 62 63 #include <net/route.h> 64 #include <net/if.h> 65 #include <net/vnet.h> 66 67 #include <netinet/cc.h> 68 #include <netinet/in.h> 69 #include <netinet/in_pcb.h> 70 #include <netinet/in_systm.h> 71 #include <netinet/in_var.h> 72 #include <netinet/ip.h> 73 #include <netinet/ip_icmp.h> 74 #include <netinet/ip_var.h> 75 #ifdef INET6 76 #include <netinet/ip6.h> 77 #include <netinet6/in6_pcb.h> 78 #include <netinet6/ip6_var.h> 79 #include <netinet6/scope6_var.h> 80 #include <netinet6/nd6.h> 81 #endif 82 83 #include <netinet/tcp_fsm.h> 84 #include <netinet/tcp_seq.h> 85 #include <netinet/tcp_timer.h> 86 #include <netinet/tcp_var.h> 87 #include <netinet/tcp_syncache.h> 88 #ifdef INET6 89 #include <netinet6/tcp6_var.h> 90 #endif 91 #include <netinet/tcpip.h> 92 #ifdef TCPDEBUG 93 #include <netinet/tcp_debug.h> 94 #endif 95 #ifdef INET6 96 #include <netinet6/ip6protosw.h> 97 #endif 98 #ifdef TCP_OFFLOAD 99 #include <netinet/tcp_offload.h> 100 #endif 101 102 #ifdef IPSEC 103 #include <netipsec/ipsec.h> 104 #include <netipsec/xform.h> 105 #ifdef INET6 106 #include <netipsec/ipsec6.h> 107 #endif 108 #include <netipsec/key.h> 109 #include <sys/syslog.h> 110 #endif /*IPSEC*/ 111 112 #include <machine/in_cksum.h> 113 #include <sys/md5.h> 114 115 #include <security/mac/mac_framework.h> 116 117 VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS; 118 #ifdef INET6 119 VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS; 120 #endif 121 122 static int 123 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS) 124 { 125 int error, new; 126 127 new = V_tcp_mssdflt; 128 error = sysctl_handle_int(oidp, &new, 0, req); 129 if (error == 0 && req->newptr) { 130 if (new < TCP_MINMSS) 131 error = EINVAL; 132 else 133 V_tcp_mssdflt = new; 134 } 135 return (error); 136 } 137 138 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, 139 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_mssdflt), 0, 140 &sysctl_net_inet_tcp_mss_check, "I", 141 "Default TCP Maximum Segment Size"); 142 143 #ifdef INET6 144 static int 145 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS) 146 { 147 int error, new; 148 149 new = V_tcp_v6mssdflt; 150 error = sysctl_handle_int(oidp, &new, 0, req); 151 if (error == 0 && req->newptr) { 152 if (new < TCP_MINMSS) 153 error = EINVAL; 154 else 155 V_tcp_v6mssdflt = new; 156 } 157 return (error); 158 } 159 160 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 161 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_v6mssdflt), 0, 162 &sysctl_net_inet_tcp_mss_v6_check, "I", 163 "Default TCP Maximum Segment Size for IPv6"); 164 #endif /* INET6 */ 165 166 /* 167 * Minimum MSS we accept and use. This prevents DoS attacks where 168 * we are forced to a ridiculous low MSS like 20 and send hundreds 169 * of packets instead of one. The effect scales with the available 170 * bandwidth and quickly saturates the CPU and network interface 171 * with packet generation and sending. Set to zero to disable MINMSS 172 * checking. This setting prevents us from sending too small packets. 173 */ 174 VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS; 175 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 176 &VNET_NAME(tcp_minmss), 0, 177 "Minmum TCP Maximum Segment Size"); 178 179 VNET_DEFINE(int, tcp_do_rfc1323) = 1; 180 SYSCTL_VNET_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 181 &VNET_NAME(tcp_do_rfc1323), 0, 182 "Enable rfc1323 (high performance TCP) extensions"); 183 184 static int tcp_log_debug = 0; 185 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW, 186 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments"); 187 188 static int tcp_tcbhashsize = 0; 189 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 190 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 191 192 static int do_tcpdrain = 1; 193 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 194 "Enable tcp_drain routine for extra help when low on mbufs"); 195 196 SYSCTL_VNET_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 197 &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs"); 198 199 static VNET_DEFINE(int, icmp_may_rst) = 1; 200 #define V_icmp_may_rst VNET(icmp_may_rst) 201 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, 202 &VNET_NAME(icmp_may_rst), 0, 203 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 204 205 static VNET_DEFINE(int, tcp_isn_reseed_interval) = 0; 206 #define V_tcp_isn_reseed_interval VNET(tcp_isn_reseed_interval) 207 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 208 &VNET_NAME(tcp_isn_reseed_interval), 0, 209 "Seconds between reseeding of ISN secret"); 210 211 static int tcp_soreceive_stream = 0; 212 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN, 213 &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets"); 214 215 #ifdef TCP_SIGNATURE 216 static int tcp_sig_checksigs = 1; 217 SYSCTL_INT(_net_inet_tcp, OID_AUTO, signature_verify_input, CTLFLAG_RW, 218 &tcp_sig_checksigs, 0, "Verify RFC2385 digests on inbound traffic"); 219 #endif 220 221 VNET_DEFINE(uma_zone_t, sack_hole_zone); 222 #define V_sack_hole_zone VNET(sack_hole_zone) 223 224 VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]); 225 226 static struct inpcb *tcp_notify(struct inpcb *, int); 227 static struct inpcb *tcp_mtudisc_notify(struct inpcb *, int); 228 static char * tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, 229 void *ip4hdr, const void *ip6hdr); 230 231 /* 232 * Target size of TCP PCB hash tables. Must be a power of two. 233 * 234 * Note that this can be overridden by the kernel environment 235 * variable net.inet.tcp.tcbhashsize 236 */ 237 #ifndef TCBHASHSIZE 238 #define TCBHASHSIZE 0 239 #endif 240 241 /* 242 * XXX 243 * Callouts should be moved into struct tcp directly. They are currently 244 * separate because the tcpcb structure is exported to userland for sysctl 245 * parsing purposes, which do not know about callouts. 246 */ 247 struct tcpcb_mem { 248 struct tcpcb tcb; 249 struct tcp_timer tt; 250 struct cc_var ccv; 251 struct osd osd; 252 }; 253 254 static VNET_DEFINE(uma_zone_t, tcpcb_zone); 255 #define V_tcpcb_zone VNET(tcpcb_zone) 256 257 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers"); 258 static struct mtx_padalign isn_mtx; 259 260 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 261 #define ISN_LOCK() mtx_lock(&isn_mtx) 262 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 263 264 /* 265 * TCP initialization. 266 */ 267 static void 268 tcp_zone_change(void *tag) 269 { 270 271 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 272 uma_zone_set_max(V_tcpcb_zone, maxsockets); 273 tcp_tw_zone_change(); 274 } 275 276 static int 277 tcp_inpcb_init(void *mem, int size, int flags) 278 { 279 struct inpcb *inp = mem; 280 281 INP_LOCK_INIT(inp, "inp", "tcpinp"); 282 return (0); 283 } 284 285 /* 286 * Take a value and get the next power of 2 that doesn't overflow. 287 * Used to size the tcp_inpcb hash buckets. 288 */ 289 static int 290 maketcp_hashsize(int size) 291 { 292 int hashsize; 293 294 /* 295 * auto tune. 296 * get the next power of 2 higher than maxsockets. 297 */ 298 hashsize = 1 << fls(size); 299 /* catch overflow, and just go one power of 2 smaller */ 300 if (hashsize < size) { 301 hashsize = 1 << (fls(size) - 1); 302 } 303 return (hashsize); 304 } 305 306 void 307 tcp_init(void) 308 { 309 const char *tcbhash_tuneable; 310 int hashsize; 311 312 tcbhash_tuneable = "net.inet.tcp.tcbhashsize"; 313 314 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN, 315 &V_tcp_hhh[HHOOK_TCP_EST_IN], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0) 316 printf("%s: WARNING: unable to register helper hook\n", __func__); 317 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT, 318 &V_tcp_hhh[HHOOK_TCP_EST_OUT], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0) 319 printf("%s: WARNING: unable to register helper hook\n", __func__); 320 321 hashsize = TCBHASHSIZE; 322 TUNABLE_INT_FETCH(tcbhash_tuneable, &hashsize); 323 if (hashsize == 0) { 324 /* 325 * Auto tune the hash size based on maxsockets. 326 * A perfect hash would have a 1:1 mapping 327 * (hashsize = maxsockets) however it's been 328 * suggested that O(2) average is better. 329 */ 330 hashsize = maketcp_hashsize(maxsockets / 4); 331 /* 332 * Our historical default is 512, 333 * do not autotune lower than this. 334 */ 335 if (hashsize < 512) 336 hashsize = 512; 337 if (bootverbose) 338 printf("%s: %s auto tuned to %d\n", __func__, 339 tcbhash_tuneable, hashsize); 340 } 341 /* 342 * We require a hashsize to be a power of two. 343 * Previously if it was not a power of two we would just reset it 344 * back to 512, which could be a nasty surprise if you did not notice 345 * the error message. 346 * Instead what we do is clip it to the closest power of two lower 347 * than the specified hash value. 348 */ 349 if (!powerof2(hashsize)) { 350 int oldhashsize = hashsize; 351 352 hashsize = maketcp_hashsize(hashsize); 353 /* prevent absurdly low value */ 354 if (hashsize < 16) 355 hashsize = 16; 356 printf("%s: WARNING: TCB hash size not a power of 2, " 357 "clipped from %d to %d.\n", __func__, oldhashsize, 358 hashsize); 359 } 360 in_pcbinfo_init(&V_tcbinfo, "tcp", &V_tcb, hashsize, hashsize, 361 "tcp_inpcb", tcp_inpcb_init, NULL, UMA_ZONE_NOFREE, 362 IPI_HASHFIELDS_4TUPLE); 363 364 /* 365 * These have to be type stable for the benefit of the timers. 366 */ 367 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 368 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 369 uma_zone_set_max(V_tcpcb_zone, maxsockets); 370 uma_zone_set_warning(V_tcpcb_zone, "kern.ipc.maxsockets limit reached"); 371 372 tcp_tw_init(); 373 syncache_init(); 374 tcp_hc_init(); 375 tcp_reass_init(); 376 377 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack); 378 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 379 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 380 381 /* Skip initialization of globals for non-default instances. */ 382 if (!IS_DEFAULT_VNET(curvnet)) 383 return; 384 385 /* XXX virtualize those bellow? */ 386 tcp_delacktime = TCPTV_DELACK; 387 tcp_keepinit = TCPTV_KEEP_INIT; 388 tcp_keepidle = TCPTV_KEEP_IDLE; 389 tcp_keepintvl = TCPTV_KEEPINTVL; 390 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 391 tcp_msl = TCPTV_MSL; 392 tcp_rexmit_min = TCPTV_MIN; 393 if (tcp_rexmit_min < 1) 394 tcp_rexmit_min = 1; 395 tcp_rexmit_slop = TCPTV_CPU_VAR; 396 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 397 tcp_tcbhashsize = hashsize; 398 399 TUNABLE_INT_FETCH("net.inet.tcp.soreceive_stream", &tcp_soreceive_stream); 400 if (tcp_soreceive_stream) { 401 #ifdef INET 402 tcp_usrreqs.pru_soreceive = soreceive_stream; 403 #endif 404 #ifdef INET6 405 tcp6_usrreqs.pru_soreceive = soreceive_stream; 406 #endif /* INET6 */ 407 } 408 409 #ifdef INET6 410 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 411 #else /* INET6 */ 412 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 413 #endif /* INET6 */ 414 if (max_protohdr < TCP_MINPROTOHDR) 415 max_protohdr = TCP_MINPROTOHDR; 416 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 417 panic("tcp_init"); 418 #undef TCP_MINPROTOHDR 419 420 ISN_LOCK_INIT(); 421 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 #ifdef VIMAGE 428 void 429 tcp_destroy(void) 430 { 431 432 tcp_reass_destroy(); 433 tcp_hc_destroy(); 434 syncache_destroy(); 435 tcp_tw_destroy(); 436 in_pcbinfo_destroy(&V_tcbinfo); 437 uma_zdestroy(V_sack_hole_zone); 438 uma_zdestroy(V_tcpcb_zone); 439 } 440 #endif 441 442 void 443 tcp_fini(void *xtp) 444 { 445 446 } 447 448 /* 449 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 450 * tcp_template used to store this data in mbufs, but we now recopy it out 451 * of the tcpcb each time to conserve mbufs. 452 */ 453 void 454 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 455 { 456 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 457 458 INP_WLOCK_ASSERT(inp); 459 460 #ifdef INET6 461 if ((inp->inp_vflag & INP_IPV6) != 0) { 462 struct ip6_hdr *ip6; 463 464 ip6 = (struct ip6_hdr *)ip_ptr; 465 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 466 (inp->inp_flow & IPV6_FLOWINFO_MASK); 467 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 468 (IPV6_VERSION & IPV6_VERSION_MASK); 469 ip6->ip6_nxt = IPPROTO_TCP; 470 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 471 ip6->ip6_src = inp->in6p_laddr; 472 ip6->ip6_dst = inp->in6p_faddr; 473 } 474 #endif /* INET6 */ 475 #if defined(INET6) && defined(INET) 476 else 477 #endif 478 #ifdef INET 479 { 480 struct ip *ip; 481 482 ip = (struct ip *)ip_ptr; 483 ip->ip_v = IPVERSION; 484 ip->ip_hl = 5; 485 ip->ip_tos = inp->inp_ip_tos; 486 ip->ip_len = 0; 487 ip->ip_id = 0; 488 ip->ip_off = 0; 489 ip->ip_ttl = inp->inp_ip_ttl; 490 ip->ip_sum = 0; 491 ip->ip_p = IPPROTO_TCP; 492 ip->ip_src = inp->inp_laddr; 493 ip->ip_dst = inp->inp_faddr; 494 } 495 #endif /* INET */ 496 th->th_sport = inp->inp_lport; 497 th->th_dport = inp->inp_fport; 498 th->th_seq = 0; 499 th->th_ack = 0; 500 th->th_x2 = 0; 501 th->th_off = 5; 502 th->th_flags = 0; 503 th->th_win = 0; 504 th->th_urp = 0; 505 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 506 } 507 508 /* 509 * Create template to be used to send tcp packets on a connection. 510 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 511 * use for this function is in keepalives, which use tcp_respond. 512 */ 513 struct tcptemp * 514 tcpip_maketemplate(struct inpcb *inp) 515 { 516 struct tcptemp *t; 517 518 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT); 519 if (t == NULL) 520 return (NULL); 521 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t); 522 return (t); 523 } 524 525 /* 526 * Send a single message to the TCP at address specified by 527 * the given TCP/IP header. If m == NULL, then we make a copy 528 * of the tcpiphdr at ti and send directly to the addressed host. 529 * This is used to force keep alive messages out using the TCP 530 * template for a connection. If flags are given then we send 531 * a message back to the TCP which originated the * segment ti, 532 * and discard the mbuf containing it and any other attached mbufs. 533 * 534 * In any case the ack and sequence number of the transmitted 535 * segment are as specified by the parameters. 536 * 537 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 538 */ 539 void 540 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 541 tcp_seq ack, tcp_seq seq, int flags) 542 { 543 int tlen; 544 int win = 0; 545 struct ip *ip; 546 struct tcphdr *nth; 547 #ifdef INET6 548 struct ip6_hdr *ip6; 549 int isipv6; 550 #endif /* INET6 */ 551 int ipflags = 0; 552 struct inpcb *inp; 553 554 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 555 556 #ifdef INET6 557 isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4); 558 ip6 = ipgen; 559 #endif /* INET6 */ 560 ip = ipgen; 561 562 if (tp != NULL) { 563 inp = tp->t_inpcb; 564 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 565 INP_WLOCK_ASSERT(inp); 566 } else 567 inp = NULL; 568 569 if (tp != NULL) { 570 if (!(flags & TH_RST)) { 571 win = sbspace(&inp->inp_socket->so_rcv); 572 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 573 win = (long)TCP_MAXWIN << tp->rcv_scale; 574 } 575 } 576 if (m == NULL) { 577 m = m_gethdr(M_NOWAIT, MT_DATA); 578 if (m == NULL) 579 return; 580 tlen = 0; 581 m->m_data += max_linkhdr; 582 #ifdef INET6 583 if (isipv6) { 584 bcopy((caddr_t)ip6, mtod(m, caddr_t), 585 sizeof(struct ip6_hdr)); 586 ip6 = mtod(m, struct ip6_hdr *); 587 nth = (struct tcphdr *)(ip6 + 1); 588 } else 589 #endif /* INET6 */ 590 { 591 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 592 ip = mtod(m, struct ip *); 593 nth = (struct tcphdr *)(ip + 1); 594 } 595 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 596 flags = TH_ACK; 597 } else { 598 /* 599 * reuse the mbuf. 600 * XXX MRT We inherrit the FIB, which is lucky. 601 */ 602 m_freem(m->m_next); 603 m->m_next = NULL; 604 m->m_data = (caddr_t)ipgen; 605 /* m_len is set later */ 606 tlen = 0; 607 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 608 #ifdef INET6 609 if (isipv6) { 610 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 611 nth = (struct tcphdr *)(ip6 + 1); 612 } else 613 #endif /* INET6 */ 614 { 615 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t); 616 nth = (struct tcphdr *)(ip + 1); 617 } 618 if (th != nth) { 619 /* 620 * this is usually a case when an extension header 621 * exists between the IPv6 header and the 622 * TCP header. 623 */ 624 nth->th_sport = th->th_sport; 625 nth->th_dport = th->th_dport; 626 } 627 xchg(nth->th_dport, nth->th_sport, uint16_t); 628 #undef xchg 629 } 630 #ifdef INET6 631 if (isipv6) { 632 ip6->ip6_flow = 0; 633 ip6->ip6_vfc = IPV6_VERSION; 634 ip6->ip6_nxt = IPPROTO_TCP; 635 ip6->ip6_plen = 0; /* Set in ip6_output(). */ 636 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 637 } 638 #endif 639 #if defined(INET) && defined(INET6) 640 else 641 #endif 642 #ifdef INET 643 { 644 tlen += sizeof (struct tcpiphdr); 645 ip->ip_len = htons(tlen); 646 ip->ip_ttl = V_ip_defttl; 647 if (V_path_mtu_discovery) 648 ip->ip_off |= htons(IP_DF); 649 } 650 #endif 651 m->m_len = tlen; 652 m->m_pkthdr.len = tlen; 653 m->m_pkthdr.rcvif = NULL; 654 #ifdef MAC 655 if (inp != NULL) { 656 /* 657 * Packet is associated with a socket, so allow the 658 * label of the response to reflect the socket label. 659 */ 660 INP_WLOCK_ASSERT(inp); 661 mac_inpcb_create_mbuf(inp, m); 662 } else { 663 /* 664 * Packet is not associated with a socket, so possibly 665 * update the label in place. 666 */ 667 mac_netinet_tcp_reply(m); 668 } 669 #endif 670 nth->th_seq = htonl(seq); 671 nth->th_ack = htonl(ack); 672 nth->th_x2 = 0; 673 nth->th_off = sizeof (struct tcphdr) >> 2; 674 nth->th_flags = flags; 675 if (tp != NULL) 676 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 677 else 678 nth->th_win = htons((u_short)win); 679 nth->th_urp = 0; 680 681 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 682 #ifdef INET6 683 if (isipv6) { 684 m->m_pkthdr.csum_flags = CSUM_TCP_IPV6; 685 nth->th_sum = in6_cksum_pseudo(ip6, 686 tlen - sizeof(struct ip6_hdr), IPPROTO_TCP, 0); 687 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 688 NULL, NULL); 689 } 690 #endif /* INET6 */ 691 #if defined(INET6) && defined(INET) 692 else 693 #endif 694 #ifdef INET 695 { 696 m->m_pkthdr.csum_flags = CSUM_TCP; 697 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 698 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 699 } 700 #endif /* INET */ 701 #ifdef TCPDEBUG 702 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 703 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 704 #endif 705 #ifdef INET6 706 if (isipv6) 707 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 708 #endif /* INET6 */ 709 #if defined(INET) && defined(INET6) 710 else 711 #endif 712 #ifdef INET 713 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 714 #endif 715 } 716 717 /* 718 * Create a new TCP control block, making an 719 * empty reassembly queue and hooking it to the argument 720 * protocol control block. The `inp' parameter must have 721 * come from the zone allocator set up in tcp_init(). 722 */ 723 struct tcpcb * 724 tcp_newtcpcb(struct inpcb *inp) 725 { 726 struct tcpcb_mem *tm; 727 struct tcpcb *tp; 728 #ifdef INET6 729 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 730 #endif /* INET6 */ 731 732 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO); 733 if (tm == NULL) 734 return (NULL); 735 tp = &tm->tcb; 736 737 /* Initialise cc_var struct for this tcpcb. */ 738 tp->ccv = &tm->ccv; 739 tp->ccv->type = IPPROTO_TCP; 740 tp->ccv->ccvc.tcp = tp; 741 742 /* 743 * Use the current system default CC algorithm. 744 */ 745 CC_LIST_RLOCK(); 746 KASSERT(!STAILQ_EMPTY(&cc_list), ("cc_list is empty!")); 747 CC_ALGO(tp) = CC_DEFAULT(); 748 CC_LIST_RUNLOCK(); 749 750 if (CC_ALGO(tp)->cb_init != NULL) 751 if (CC_ALGO(tp)->cb_init(tp->ccv) > 0) { 752 uma_zfree(V_tcpcb_zone, tm); 753 return (NULL); 754 } 755 756 tp->osd = &tm->osd; 757 if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) { 758 uma_zfree(V_tcpcb_zone, tm); 759 return (NULL); 760 } 761 762 #ifdef VIMAGE 763 tp->t_vnet = inp->inp_vnet; 764 #endif 765 tp->t_timers = &tm->tt; 766 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 767 tp->t_maxseg = tp->t_maxopd = 768 #ifdef INET6 769 isipv6 ? V_tcp_v6mssdflt : 770 #endif /* INET6 */ 771 V_tcp_mssdflt; 772 773 /* Set up our timeouts. */ 774 callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE); 775 callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE); 776 callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE); 777 callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE); 778 callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE); 779 780 if (V_tcp_do_rfc1323) 781 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 782 if (V_tcp_do_sack) 783 tp->t_flags |= TF_SACK_PERMIT; 784 TAILQ_INIT(&tp->snd_holes); 785 tp->t_inpcb = inp; /* XXX */ 786 /* 787 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 788 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 789 * reasonable initial retransmit time. 790 */ 791 tp->t_srtt = TCPTV_SRTTBASE; 792 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 793 tp->t_rttmin = tcp_rexmit_min; 794 tp->t_rxtcur = TCPTV_RTOBASE; 795 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 796 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 797 tp->t_rcvtime = ticks; 798 /* 799 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 800 * because the socket may be bound to an IPv6 wildcard address, 801 * which may match an IPv4-mapped IPv6 address. 802 */ 803 inp->inp_ip_ttl = V_ip_defttl; 804 inp->inp_ppcb = tp; 805 return (tp); /* XXX */ 806 } 807 808 /* 809 * Switch the congestion control algorithm back to NewReno for any active 810 * control blocks using an algorithm which is about to go away. 811 * This ensures the CC framework can allow the unload to proceed without leaving 812 * any dangling pointers which would trigger a panic. 813 * Returning non-zero would inform the CC framework that something went wrong 814 * and it would be unsafe to allow the unload to proceed. However, there is no 815 * way for this to occur with this implementation so we always return zero. 816 */ 817 int 818 tcp_ccalgounload(struct cc_algo *unload_algo) 819 { 820 struct cc_algo *tmpalgo; 821 struct inpcb *inp; 822 struct tcpcb *tp; 823 VNET_ITERATOR_DECL(vnet_iter); 824 825 /* 826 * Check all active control blocks across all network stacks and change 827 * any that are using "unload_algo" back to NewReno. If "unload_algo" 828 * requires cleanup code to be run, call it. 829 */ 830 VNET_LIST_RLOCK(); 831 VNET_FOREACH(vnet_iter) { 832 CURVNET_SET(vnet_iter); 833 INP_INFO_RLOCK(&V_tcbinfo); 834 /* 835 * New connections already part way through being initialised 836 * with the CC algo we're removing will not race with this code 837 * because the INP_INFO_WLOCK is held during initialisation. We 838 * therefore don't enter the loop below until the connection 839 * list has stabilised. 840 */ 841 LIST_FOREACH(inp, &V_tcb, inp_list) { 842 INP_WLOCK(inp); 843 /* Important to skip tcptw structs. */ 844 if (!(inp->inp_flags & INP_TIMEWAIT) && 845 (tp = intotcpcb(inp)) != NULL) { 846 /* 847 * By holding INP_WLOCK here, we are assured 848 * that the connection is not currently 849 * executing inside the CC module's functions 850 * i.e. it is safe to make the switch back to 851 * NewReno. 852 */ 853 if (CC_ALGO(tp) == unload_algo) { 854 tmpalgo = CC_ALGO(tp); 855 /* NewReno does not require any init. */ 856 CC_ALGO(tp) = &newreno_cc_algo; 857 if (tmpalgo->cb_destroy != NULL) 858 tmpalgo->cb_destroy(tp->ccv); 859 } 860 } 861 INP_WUNLOCK(inp); 862 } 863 INP_INFO_RUNLOCK(&V_tcbinfo); 864 CURVNET_RESTORE(); 865 } 866 VNET_LIST_RUNLOCK(); 867 868 return (0); 869 } 870 871 /* 872 * Drop a TCP connection, reporting 873 * the specified error. If connection is synchronized, 874 * then send a RST to peer. 875 */ 876 struct tcpcb * 877 tcp_drop(struct tcpcb *tp, int errno) 878 { 879 struct socket *so = tp->t_inpcb->inp_socket; 880 881 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 882 INP_WLOCK_ASSERT(tp->t_inpcb); 883 884 if (TCPS_HAVERCVDSYN(tp->t_state)) { 885 tp->t_state = TCPS_CLOSED; 886 (void) tcp_output(tp); 887 TCPSTAT_INC(tcps_drops); 888 } else 889 TCPSTAT_INC(tcps_conndrops); 890 if (errno == ETIMEDOUT && tp->t_softerror) 891 errno = tp->t_softerror; 892 so->so_error = errno; 893 return (tcp_close(tp)); 894 } 895 896 void 897 tcp_discardcb(struct tcpcb *tp) 898 { 899 struct inpcb *inp = tp->t_inpcb; 900 struct socket *so = inp->inp_socket; 901 #ifdef INET6 902 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 903 #endif /* INET6 */ 904 905 INP_WLOCK_ASSERT(inp); 906 907 /* 908 * Make sure that all of our timers are stopped before we delete the 909 * PCB. 910 * 911 * XXXRW: Really, we would like to use callout_drain() here in order 912 * to avoid races experienced in tcp_timer.c where a timer is already 913 * executing at this point. However, we can't, both because we're 914 * running in a context where we can't sleep, and also because we 915 * hold locks required by the timers. What we instead need to do is 916 * test to see if callout_drain() is required, and if so, defer some 917 * portion of the remainder of tcp_discardcb() to an asynchronous 918 * context that can callout_drain() and then continue. Some care 919 * will be required to ensure that no further processing takes place 920 * on the tcpcb, even though it hasn't been freed (a flag?). 921 */ 922 callout_stop(&tp->t_timers->tt_rexmt); 923 callout_stop(&tp->t_timers->tt_persist); 924 callout_stop(&tp->t_timers->tt_keep); 925 callout_stop(&tp->t_timers->tt_2msl); 926 callout_stop(&tp->t_timers->tt_delack); 927 928 /* 929 * If we got enough samples through the srtt filter, 930 * save the rtt and rttvar in the routing entry. 931 * 'Enough' is arbitrarily defined as 4 rtt samples. 932 * 4 samples is enough for the srtt filter to converge 933 * to within enough % of the correct value; fewer samples 934 * and we could save a bogus rtt. The danger is not high 935 * as tcp quickly recovers from everything. 936 * XXX: Works very well but needs some more statistics! 937 */ 938 if (tp->t_rttupdated >= 4) { 939 struct hc_metrics_lite metrics; 940 u_long ssthresh; 941 942 bzero(&metrics, sizeof(metrics)); 943 /* 944 * Update the ssthresh always when the conditions below 945 * are satisfied. This gives us better new start value 946 * for the congestion avoidance for new connections. 947 * ssthresh is only set if packet loss occured on a session. 948 * 949 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 950 * being torn down. Ideally this code would not use 'so'. 951 */ 952 ssthresh = tp->snd_ssthresh; 953 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 954 /* 955 * convert the limit from user data bytes to 956 * packets then to packet data bytes. 957 */ 958 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 959 if (ssthresh < 2) 960 ssthresh = 2; 961 ssthresh *= (u_long)(tp->t_maxseg + 962 #ifdef INET6 963 (isipv6 ? sizeof (struct ip6_hdr) + 964 sizeof (struct tcphdr) : 965 #endif 966 sizeof (struct tcpiphdr) 967 #ifdef INET6 968 ) 969 #endif 970 ); 971 } else 972 ssthresh = 0; 973 metrics.rmx_ssthresh = ssthresh; 974 975 metrics.rmx_rtt = tp->t_srtt; 976 metrics.rmx_rttvar = tp->t_rttvar; 977 metrics.rmx_cwnd = tp->snd_cwnd; 978 metrics.rmx_sendpipe = 0; 979 metrics.rmx_recvpipe = 0; 980 981 tcp_hc_update(&inp->inp_inc, &metrics); 982 } 983 984 /* free the reassembly queue, if any */ 985 tcp_reass_flush(tp); 986 987 #ifdef TCP_OFFLOAD 988 /* Disconnect offload device, if any. */ 989 if (tp->t_flags & TF_TOE) 990 tcp_offload_detach(tp); 991 #endif 992 993 tcp_free_sackholes(tp); 994 995 /* Allow the CC algorithm to clean up after itself. */ 996 if (CC_ALGO(tp)->cb_destroy != NULL) 997 CC_ALGO(tp)->cb_destroy(tp->ccv); 998 999 khelp_destroy_osd(tp->osd); 1000 1001 CC_ALGO(tp) = NULL; 1002 inp->inp_ppcb = NULL; 1003 tp->t_inpcb = NULL; 1004 uma_zfree(V_tcpcb_zone, tp); 1005 } 1006 1007 /* 1008 * Attempt to close a TCP control block, marking it as dropped, and freeing 1009 * the socket if we hold the only reference. 1010 */ 1011 struct tcpcb * 1012 tcp_close(struct tcpcb *tp) 1013 { 1014 struct inpcb *inp = tp->t_inpcb; 1015 struct socket *so; 1016 1017 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 1018 INP_WLOCK_ASSERT(inp); 1019 1020 #ifdef TCP_OFFLOAD 1021 if (tp->t_state == TCPS_LISTEN) 1022 tcp_offload_listen_stop(tp); 1023 #endif 1024 in_pcbdrop(inp); 1025 TCPSTAT_INC(tcps_closed); 1026 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 1027 so = inp->inp_socket; 1028 soisdisconnected(so); 1029 if (inp->inp_flags & INP_SOCKREF) { 1030 KASSERT(so->so_state & SS_PROTOREF, 1031 ("tcp_close: !SS_PROTOREF")); 1032 inp->inp_flags &= ~INP_SOCKREF; 1033 INP_WUNLOCK(inp); 1034 ACCEPT_LOCK(); 1035 SOCK_LOCK(so); 1036 so->so_state &= ~SS_PROTOREF; 1037 sofree(so); 1038 return (NULL); 1039 } 1040 return (tp); 1041 } 1042 1043 void 1044 tcp_drain(void) 1045 { 1046 VNET_ITERATOR_DECL(vnet_iter); 1047 1048 if (!do_tcpdrain) 1049 return; 1050 1051 VNET_LIST_RLOCK_NOSLEEP(); 1052 VNET_FOREACH(vnet_iter) { 1053 CURVNET_SET(vnet_iter); 1054 struct inpcb *inpb; 1055 struct tcpcb *tcpb; 1056 1057 /* 1058 * Walk the tcpbs, if existing, and flush the reassembly queue, 1059 * if there is one... 1060 * XXX: The "Net/3" implementation doesn't imply that the TCP 1061 * reassembly queue should be flushed, but in a situation 1062 * where we're really low on mbufs, this is potentially 1063 * usefull. 1064 */ 1065 INP_INFO_RLOCK(&V_tcbinfo); 1066 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) { 1067 if (inpb->inp_flags & INP_TIMEWAIT) 1068 continue; 1069 INP_WLOCK(inpb); 1070 if ((tcpb = intotcpcb(inpb)) != NULL) { 1071 tcp_reass_flush(tcpb); 1072 tcp_clean_sackreport(tcpb); 1073 } 1074 INP_WUNLOCK(inpb); 1075 } 1076 INP_INFO_RUNLOCK(&V_tcbinfo); 1077 CURVNET_RESTORE(); 1078 } 1079 VNET_LIST_RUNLOCK_NOSLEEP(); 1080 } 1081 1082 /* 1083 * Notify a tcp user of an asynchronous error; 1084 * store error as soft error, but wake up user 1085 * (for now, won't do anything until can select for soft error). 1086 * 1087 * Do not wake up user since there currently is no mechanism for 1088 * reporting soft errors (yet - a kqueue filter may be added). 1089 */ 1090 static struct inpcb * 1091 tcp_notify(struct inpcb *inp, int error) 1092 { 1093 struct tcpcb *tp; 1094 1095 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 1096 INP_WLOCK_ASSERT(inp); 1097 1098 if ((inp->inp_flags & INP_TIMEWAIT) || 1099 (inp->inp_flags & INP_DROPPED)) 1100 return (inp); 1101 1102 tp = intotcpcb(inp); 1103 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 1104 1105 /* 1106 * Ignore some errors if we are hooked up. 1107 * If connection hasn't completed, has retransmitted several times, 1108 * and receives a second error, give up now. This is better 1109 * than waiting a long time to establish a connection that 1110 * can never complete. 1111 */ 1112 if (tp->t_state == TCPS_ESTABLISHED && 1113 (error == EHOSTUNREACH || error == ENETUNREACH || 1114 error == EHOSTDOWN)) { 1115 return (inp); 1116 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1117 tp->t_softerror) { 1118 tp = tcp_drop(tp, error); 1119 if (tp != NULL) 1120 return (inp); 1121 else 1122 return (NULL); 1123 } else { 1124 tp->t_softerror = error; 1125 return (inp); 1126 } 1127 #if 0 1128 wakeup( &so->so_timeo); 1129 sorwakeup(so); 1130 sowwakeup(so); 1131 #endif 1132 } 1133 1134 static int 1135 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1136 { 1137 int error, i, m, n, pcb_count; 1138 struct inpcb *inp, **inp_list; 1139 inp_gen_t gencnt; 1140 struct xinpgen xig; 1141 1142 /* 1143 * The process of preparing the TCB list is too time-consuming and 1144 * resource-intensive to repeat twice on every request. 1145 */ 1146 if (req->oldptr == NULL) { 1147 n = V_tcbinfo.ipi_count + syncache_pcbcount(); 1148 n += imax(n / 8, 10); 1149 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb); 1150 return (0); 1151 } 1152 1153 if (req->newptr != NULL) 1154 return (EPERM); 1155 1156 /* 1157 * OK, now we're committed to doing something. 1158 */ 1159 INP_INFO_RLOCK(&V_tcbinfo); 1160 gencnt = V_tcbinfo.ipi_gencnt; 1161 n = V_tcbinfo.ipi_count; 1162 INP_INFO_RUNLOCK(&V_tcbinfo); 1163 1164 m = syncache_pcbcount(); 1165 1166 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 1167 + (n + m) * sizeof(struct xtcpcb)); 1168 if (error != 0) 1169 return (error); 1170 1171 xig.xig_len = sizeof xig; 1172 xig.xig_count = n + m; 1173 xig.xig_gen = gencnt; 1174 xig.xig_sogen = so_gencnt; 1175 error = SYSCTL_OUT(req, &xig, sizeof xig); 1176 if (error) 1177 return (error); 1178 1179 error = syncache_pcblist(req, m, &pcb_count); 1180 if (error) 1181 return (error); 1182 1183 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 1184 if (inp_list == NULL) 1185 return (ENOMEM); 1186 1187 INP_INFO_RLOCK(&V_tcbinfo); 1188 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0; 1189 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) { 1190 INP_WLOCK(inp); 1191 if (inp->inp_gencnt <= gencnt) { 1192 /* 1193 * XXX: This use of cr_cansee(), introduced with 1194 * TCP state changes, is not quite right, but for 1195 * now, better than nothing. 1196 */ 1197 if (inp->inp_flags & INP_TIMEWAIT) { 1198 if (intotw(inp) != NULL) 1199 error = cr_cansee(req->td->td_ucred, 1200 intotw(inp)->tw_cred); 1201 else 1202 error = EINVAL; /* Skip this inp. */ 1203 } else 1204 error = cr_canseeinpcb(req->td->td_ucred, inp); 1205 if (error == 0) { 1206 in_pcbref(inp); 1207 inp_list[i++] = inp; 1208 } 1209 } 1210 INP_WUNLOCK(inp); 1211 } 1212 INP_INFO_RUNLOCK(&V_tcbinfo); 1213 n = i; 1214 1215 error = 0; 1216 for (i = 0; i < n; i++) { 1217 inp = inp_list[i]; 1218 INP_RLOCK(inp); 1219 if (inp->inp_gencnt <= gencnt) { 1220 struct xtcpcb xt; 1221 void *inp_ppcb; 1222 1223 bzero(&xt, sizeof(xt)); 1224 xt.xt_len = sizeof xt; 1225 /* XXX should avoid extra copy */ 1226 bcopy(inp, &xt.xt_inp, sizeof *inp); 1227 inp_ppcb = inp->inp_ppcb; 1228 if (inp_ppcb == NULL) 1229 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1230 else if (inp->inp_flags & INP_TIMEWAIT) { 1231 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1232 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1233 } else { 1234 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1235 if (xt.xt_tp.t_timers) 1236 tcp_timer_to_xtimer(&xt.xt_tp, xt.xt_tp.t_timers, &xt.xt_timer); 1237 } 1238 if (inp->inp_socket != NULL) 1239 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1240 else { 1241 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1242 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1243 } 1244 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1245 INP_RUNLOCK(inp); 1246 error = SYSCTL_OUT(req, &xt, sizeof xt); 1247 } else 1248 INP_RUNLOCK(inp); 1249 } 1250 INP_INFO_WLOCK(&V_tcbinfo); 1251 for (i = 0; i < n; i++) { 1252 inp = inp_list[i]; 1253 INP_RLOCK(inp); 1254 if (!in_pcbrele_rlocked(inp)) 1255 INP_RUNLOCK(inp); 1256 } 1257 INP_INFO_WUNLOCK(&V_tcbinfo); 1258 1259 if (!error) { 1260 /* 1261 * Give the user an updated idea of our state. 1262 * If the generation differs from what we told 1263 * her before, she knows that something happened 1264 * while we were processing this request, and it 1265 * might be necessary to retry. 1266 */ 1267 INP_INFO_RLOCK(&V_tcbinfo); 1268 xig.xig_gen = V_tcbinfo.ipi_gencnt; 1269 xig.xig_sogen = so_gencnt; 1270 xig.xig_count = V_tcbinfo.ipi_count + pcb_count; 1271 INP_INFO_RUNLOCK(&V_tcbinfo); 1272 error = SYSCTL_OUT(req, &xig, sizeof xig); 1273 } 1274 free(inp_list, M_TEMP); 1275 return (error); 1276 } 1277 1278 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, 1279 CTLTYPE_OPAQUE | CTLFLAG_RD, NULL, 0, 1280 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1281 1282 #ifdef INET 1283 static int 1284 tcp_getcred(SYSCTL_HANDLER_ARGS) 1285 { 1286 struct xucred xuc; 1287 struct sockaddr_in addrs[2]; 1288 struct inpcb *inp; 1289 int error; 1290 1291 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1292 if (error) 1293 return (error); 1294 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1295 if (error) 1296 return (error); 1297 inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 1298 addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL); 1299 if (inp != NULL) { 1300 if (inp->inp_socket == NULL) 1301 error = ENOENT; 1302 if (error == 0) 1303 error = cr_canseeinpcb(req->td->td_ucred, inp); 1304 if (error == 0) 1305 cru2x(inp->inp_cred, &xuc); 1306 INP_RUNLOCK(inp); 1307 } else 1308 error = ENOENT; 1309 if (error == 0) 1310 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1311 return (error); 1312 } 1313 1314 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1315 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1316 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1317 #endif /* INET */ 1318 1319 #ifdef INET6 1320 static int 1321 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1322 { 1323 struct xucred xuc; 1324 struct sockaddr_in6 addrs[2]; 1325 struct inpcb *inp; 1326 int error; 1327 #ifdef INET 1328 int mapped = 0; 1329 #endif 1330 1331 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1332 if (error) 1333 return (error); 1334 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1335 if (error) 1336 return (error); 1337 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 || 1338 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) { 1339 return (error); 1340 } 1341 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1342 #ifdef INET 1343 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1344 mapped = 1; 1345 else 1346 #endif 1347 return (EINVAL); 1348 } 1349 1350 #ifdef INET 1351 if (mapped == 1) 1352 inp = in_pcblookup(&V_tcbinfo, 1353 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1354 addrs[1].sin6_port, 1355 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1356 addrs[0].sin6_port, INPLOOKUP_RLOCKPCB, NULL); 1357 else 1358 #endif 1359 inp = in6_pcblookup(&V_tcbinfo, 1360 &addrs[1].sin6_addr, addrs[1].sin6_port, 1361 &addrs[0].sin6_addr, addrs[0].sin6_port, 1362 INPLOOKUP_RLOCKPCB, NULL); 1363 if (inp != NULL) { 1364 if (inp->inp_socket == NULL) 1365 error = ENOENT; 1366 if (error == 0) 1367 error = cr_canseeinpcb(req->td->td_ucred, inp); 1368 if (error == 0) 1369 cru2x(inp->inp_cred, &xuc); 1370 INP_RUNLOCK(inp); 1371 } else 1372 error = ENOENT; 1373 if (error == 0) 1374 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1375 return (error); 1376 } 1377 1378 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1379 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1380 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1381 #endif /* INET6 */ 1382 1383 1384 #ifdef INET 1385 void 1386 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1387 { 1388 struct ip *ip = vip; 1389 struct tcphdr *th; 1390 struct in_addr faddr; 1391 struct inpcb *inp; 1392 struct tcpcb *tp; 1393 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1394 struct icmp *icp; 1395 struct in_conninfo inc; 1396 tcp_seq icmp_tcp_seq; 1397 int mtu; 1398 1399 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1400 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1401 return; 1402 1403 if (cmd == PRC_MSGSIZE) 1404 notify = tcp_mtudisc_notify; 1405 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1406 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1407 notify = tcp_drop_syn_sent; 1408 /* 1409 * Redirects don't need to be handled up here. 1410 */ 1411 else if (PRC_IS_REDIRECT(cmd)) 1412 return; 1413 /* 1414 * Source quench is depreciated. 1415 */ 1416 else if (cmd == PRC_QUENCH) 1417 return; 1418 /* 1419 * Hostdead is ugly because it goes linearly through all PCBs. 1420 * XXX: We never get this from ICMP, otherwise it makes an 1421 * excellent DoS attack on machines with many connections. 1422 */ 1423 else if (cmd == PRC_HOSTDEAD) 1424 ip = NULL; 1425 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1426 return; 1427 if (ip != NULL) { 1428 icp = (struct icmp *)((caddr_t)ip 1429 - offsetof(struct icmp, icmp_ip)); 1430 th = (struct tcphdr *)((caddr_t)ip 1431 + (ip->ip_hl << 2)); 1432 INP_INFO_WLOCK(&V_tcbinfo); 1433 inp = in_pcblookup(&V_tcbinfo, faddr, th->th_dport, 1434 ip->ip_src, th->th_sport, INPLOOKUP_WLOCKPCB, NULL); 1435 if (inp != NULL) { 1436 if (!(inp->inp_flags & INP_TIMEWAIT) && 1437 !(inp->inp_flags & INP_DROPPED) && 1438 !(inp->inp_socket == NULL)) { 1439 icmp_tcp_seq = htonl(th->th_seq); 1440 tp = intotcpcb(inp); 1441 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1442 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1443 if (cmd == PRC_MSGSIZE) { 1444 /* 1445 * MTU discovery: 1446 * If we got a needfrag set the MTU 1447 * in the route to the suggested new 1448 * value (if given) and then notify. 1449 */ 1450 bzero(&inc, sizeof(inc)); 1451 inc.inc_faddr = faddr; 1452 inc.inc_fibnum = 1453 inp->inp_inc.inc_fibnum; 1454 1455 mtu = ntohs(icp->icmp_nextmtu); 1456 /* 1457 * If no alternative MTU was 1458 * proposed, try the next smaller 1459 * one. 1460 */ 1461 if (!mtu) 1462 mtu = ip_next_mtu( 1463 ntohs(ip->ip_len), 1); 1464 if (mtu < V_tcp_minmss 1465 + sizeof(struct tcpiphdr)) 1466 mtu = V_tcp_minmss 1467 + sizeof(struct tcpiphdr); 1468 /* 1469 * Only cache the MTU if it 1470 * is smaller than the interface 1471 * or route MTU. tcp_mtudisc() 1472 * will do right thing by itself. 1473 */ 1474 if (mtu <= tcp_maxmtu(&inc, NULL)) 1475 tcp_hc_updatemtu(&inc, mtu); 1476 tcp_mtudisc(inp, mtu); 1477 } else 1478 inp = (*notify)(inp, 1479 inetctlerrmap[cmd]); 1480 } 1481 } 1482 if (inp != NULL) 1483 INP_WUNLOCK(inp); 1484 } else { 1485 bzero(&inc, sizeof(inc)); 1486 inc.inc_fport = th->th_dport; 1487 inc.inc_lport = th->th_sport; 1488 inc.inc_faddr = faddr; 1489 inc.inc_laddr = ip->ip_src; 1490 syncache_unreach(&inc, th); 1491 } 1492 INP_INFO_WUNLOCK(&V_tcbinfo); 1493 } else 1494 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify); 1495 } 1496 #endif /* INET */ 1497 1498 #ifdef INET6 1499 void 1500 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1501 { 1502 struct tcphdr th; 1503 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1504 struct ip6_hdr *ip6; 1505 struct mbuf *m; 1506 struct ip6ctlparam *ip6cp = NULL; 1507 const struct sockaddr_in6 *sa6_src = NULL; 1508 int off; 1509 struct tcp_portonly { 1510 u_int16_t th_sport; 1511 u_int16_t th_dport; 1512 } *thp; 1513 1514 if (sa->sa_family != AF_INET6 || 1515 sa->sa_len != sizeof(struct sockaddr_in6)) 1516 return; 1517 1518 if (cmd == PRC_MSGSIZE) 1519 notify = tcp_mtudisc_notify; 1520 else if (!PRC_IS_REDIRECT(cmd) && 1521 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1522 return; 1523 /* Source quench is depreciated. */ 1524 else if (cmd == PRC_QUENCH) 1525 return; 1526 1527 /* if the parameter is from icmp6, decode it. */ 1528 if (d != NULL) { 1529 ip6cp = (struct ip6ctlparam *)d; 1530 m = ip6cp->ip6c_m; 1531 ip6 = ip6cp->ip6c_ip6; 1532 off = ip6cp->ip6c_off; 1533 sa6_src = ip6cp->ip6c_src; 1534 } else { 1535 m = NULL; 1536 ip6 = NULL; 1537 off = 0; /* fool gcc */ 1538 sa6_src = &sa6_any; 1539 } 1540 1541 if (ip6 != NULL) { 1542 struct in_conninfo inc; 1543 /* 1544 * XXX: We assume that when IPV6 is non NULL, 1545 * M and OFF are valid. 1546 */ 1547 1548 /* check if we can safely examine src and dst ports */ 1549 if (m->m_pkthdr.len < off + sizeof(*thp)) 1550 return; 1551 1552 bzero(&th, sizeof(th)); 1553 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1554 1555 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport, 1556 (struct sockaddr *)ip6cp->ip6c_src, 1557 th.th_sport, cmd, NULL, notify); 1558 1559 bzero(&inc, sizeof(inc)); 1560 inc.inc_fport = th.th_dport; 1561 inc.inc_lport = th.th_sport; 1562 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1563 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1564 inc.inc_flags |= INC_ISIPV6; 1565 INP_INFO_WLOCK(&V_tcbinfo); 1566 syncache_unreach(&inc, &th); 1567 INP_INFO_WUNLOCK(&V_tcbinfo); 1568 } else 1569 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1570 0, cmd, NULL, notify); 1571 } 1572 #endif /* INET6 */ 1573 1574 1575 /* 1576 * Following is where TCP initial sequence number generation occurs. 1577 * 1578 * There are two places where we must use initial sequence numbers: 1579 * 1. In SYN-ACK packets. 1580 * 2. In SYN packets. 1581 * 1582 * All ISNs for SYN-ACK packets are generated by the syncache. See 1583 * tcp_syncache.c for details. 1584 * 1585 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1586 * depends on this property. In addition, these ISNs should be 1587 * unguessable so as to prevent connection hijacking. To satisfy 1588 * the requirements of this situation, the algorithm outlined in 1589 * RFC 1948 is used, with only small modifications. 1590 * 1591 * Implementation details: 1592 * 1593 * Time is based off the system timer, and is corrected so that it 1594 * increases by one megabyte per second. This allows for proper 1595 * recycling on high speed LANs while still leaving over an hour 1596 * before rollover. 1597 * 1598 * As reading the *exact* system time is too expensive to be done 1599 * whenever setting up a TCP connection, we increment the time 1600 * offset in two ways. First, a small random positive increment 1601 * is added to isn_offset for each connection that is set up. 1602 * Second, the function tcp_isn_tick fires once per clock tick 1603 * and increments isn_offset as necessary so that sequence numbers 1604 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1605 * random positive increments serve only to ensure that the same 1606 * exact sequence number is never sent out twice (as could otherwise 1607 * happen when a port is recycled in less than the system tick 1608 * interval.) 1609 * 1610 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1611 * between seeding of isn_secret. This is normally set to zero, 1612 * as reseeding should not be necessary. 1613 * 1614 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1615 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1616 * general, this means holding an exclusive (write) lock. 1617 */ 1618 1619 #define ISN_BYTES_PER_SECOND 1048576 1620 #define ISN_STATIC_INCREMENT 4096 1621 #define ISN_RANDOM_INCREMENT (4096 - 1) 1622 1623 static VNET_DEFINE(u_char, isn_secret[32]); 1624 static VNET_DEFINE(int, isn_last); 1625 static VNET_DEFINE(int, isn_last_reseed); 1626 static VNET_DEFINE(u_int32_t, isn_offset); 1627 static VNET_DEFINE(u_int32_t, isn_offset_old); 1628 1629 #define V_isn_secret VNET(isn_secret) 1630 #define V_isn_last VNET(isn_last) 1631 #define V_isn_last_reseed VNET(isn_last_reseed) 1632 #define V_isn_offset VNET(isn_offset) 1633 #define V_isn_offset_old VNET(isn_offset_old) 1634 1635 tcp_seq 1636 tcp_new_isn(struct tcpcb *tp) 1637 { 1638 MD5_CTX isn_ctx; 1639 u_int32_t md5_buffer[4]; 1640 tcp_seq new_isn; 1641 u_int32_t projected_offset; 1642 1643 INP_WLOCK_ASSERT(tp->t_inpcb); 1644 1645 ISN_LOCK(); 1646 /* Seed if this is the first use, reseed if requested. */ 1647 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) && 1648 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz) 1649 < (u_int)ticks))) { 1650 read_random(&V_isn_secret, sizeof(V_isn_secret)); 1651 V_isn_last_reseed = ticks; 1652 } 1653 1654 /* Compute the md5 hash and return the ISN. */ 1655 MD5Init(&isn_ctx); 1656 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1657 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1658 #ifdef INET6 1659 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1660 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1661 sizeof(struct in6_addr)); 1662 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1663 sizeof(struct in6_addr)); 1664 } else 1665 #endif 1666 { 1667 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1668 sizeof(struct in_addr)); 1669 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1670 sizeof(struct in_addr)); 1671 } 1672 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret)); 1673 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1674 new_isn = (tcp_seq) md5_buffer[0]; 1675 V_isn_offset += ISN_STATIC_INCREMENT + 1676 (arc4random() & ISN_RANDOM_INCREMENT); 1677 if (ticks != V_isn_last) { 1678 projected_offset = V_isn_offset_old + 1679 ISN_BYTES_PER_SECOND / hz * (ticks - V_isn_last); 1680 if (SEQ_GT(projected_offset, V_isn_offset)) 1681 V_isn_offset = projected_offset; 1682 V_isn_offset_old = V_isn_offset; 1683 V_isn_last = ticks; 1684 } 1685 new_isn += V_isn_offset; 1686 ISN_UNLOCK(); 1687 return (new_isn); 1688 } 1689 1690 /* 1691 * When a specific ICMP unreachable message is received and the 1692 * connection state is SYN-SENT, drop the connection. This behavior 1693 * is controlled by the icmp_may_rst sysctl. 1694 */ 1695 struct inpcb * 1696 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1697 { 1698 struct tcpcb *tp; 1699 1700 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 1701 INP_WLOCK_ASSERT(inp); 1702 1703 if ((inp->inp_flags & INP_TIMEWAIT) || 1704 (inp->inp_flags & INP_DROPPED)) 1705 return (inp); 1706 1707 tp = intotcpcb(inp); 1708 if (tp->t_state != TCPS_SYN_SENT) 1709 return (inp); 1710 1711 tp = tcp_drop(tp, errno); 1712 if (tp != NULL) 1713 return (inp); 1714 else 1715 return (NULL); 1716 } 1717 1718 /* 1719 * When `need fragmentation' ICMP is received, update our idea of the MSS 1720 * based on the new value. Also nudge TCP to send something, since we 1721 * know the packet we just sent was dropped. 1722 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1723 */ 1724 static struct inpcb * 1725 tcp_mtudisc_notify(struct inpcb *inp, int error) 1726 { 1727 1728 return (tcp_mtudisc(inp, -1)); 1729 } 1730 1731 struct inpcb * 1732 tcp_mtudisc(struct inpcb *inp, int mtuoffer) 1733 { 1734 struct tcpcb *tp; 1735 struct socket *so; 1736 1737 INP_WLOCK_ASSERT(inp); 1738 if ((inp->inp_flags & INP_TIMEWAIT) || 1739 (inp->inp_flags & INP_DROPPED)) 1740 return (inp); 1741 1742 tp = intotcpcb(inp); 1743 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1744 1745 tcp_mss_update(tp, -1, mtuoffer, NULL, NULL); 1746 1747 so = inp->inp_socket; 1748 SOCKBUF_LOCK(&so->so_snd); 1749 /* If the mss is larger than the socket buffer, decrease the mss. */ 1750 if (so->so_snd.sb_hiwat < tp->t_maxseg) 1751 tp->t_maxseg = so->so_snd.sb_hiwat; 1752 SOCKBUF_UNLOCK(&so->so_snd); 1753 1754 TCPSTAT_INC(tcps_mturesent); 1755 tp->t_rtttime = 0; 1756 tp->snd_nxt = tp->snd_una; 1757 tcp_free_sackholes(tp); 1758 tp->snd_recover = tp->snd_max; 1759 if (tp->t_flags & TF_SACK_PERMIT) 1760 EXIT_FASTRECOVERY(tp->t_flags); 1761 tcp_output(tp); 1762 return (inp); 1763 } 1764 1765 #ifdef INET 1766 /* 1767 * Look-up the routing entry to the peer of this inpcb. If no route 1768 * is found and it cannot be allocated, then return 0. This routine 1769 * is called by TCP routines that access the rmx structure and by 1770 * tcp_mss_update to get the peer/interface MTU. 1771 */ 1772 u_long 1773 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1774 { 1775 struct route sro; 1776 struct sockaddr_in *dst; 1777 struct ifnet *ifp; 1778 u_long maxmtu = 0; 1779 1780 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1781 1782 bzero(&sro, sizeof(sro)); 1783 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1784 dst = (struct sockaddr_in *)&sro.ro_dst; 1785 dst->sin_family = AF_INET; 1786 dst->sin_len = sizeof(*dst); 1787 dst->sin_addr = inc->inc_faddr; 1788 in_rtalloc_ign(&sro, 0, inc->inc_fibnum); 1789 } 1790 if (sro.ro_rt != NULL) { 1791 ifp = sro.ro_rt->rt_ifp; 1792 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1793 maxmtu = ifp->if_mtu; 1794 else 1795 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1796 1797 /* Report additional interface capabilities. */ 1798 if (flags != NULL) { 1799 if (ifp->if_capenable & IFCAP_TSO4 && 1800 ifp->if_hwassist & CSUM_TSO) 1801 *flags |= CSUM_TSO; 1802 } 1803 RTFREE(sro.ro_rt); 1804 } 1805 return (maxmtu); 1806 } 1807 #endif /* INET */ 1808 1809 #ifdef INET6 1810 u_long 1811 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1812 { 1813 struct route_in6 sro6; 1814 struct ifnet *ifp; 1815 u_long maxmtu = 0; 1816 1817 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1818 1819 bzero(&sro6, sizeof(sro6)); 1820 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1821 sro6.ro_dst.sin6_family = AF_INET6; 1822 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1823 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1824 in6_rtalloc_ign(&sro6, 0, inc->inc_fibnum); 1825 } 1826 if (sro6.ro_rt != NULL) { 1827 ifp = sro6.ro_rt->rt_ifp; 1828 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1829 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1830 else 1831 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1832 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1833 1834 /* Report additional interface capabilities. */ 1835 if (flags != NULL) { 1836 if (ifp->if_capenable & IFCAP_TSO6 && 1837 ifp->if_hwassist & CSUM_TSO) 1838 *flags |= CSUM_TSO; 1839 } 1840 RTFREE(sro6.ro_rt); 1841 } 1842 1843 return (maxmtu); 1844 } 1845 #endif /* INET6 */ 1846 1847 #ifdef IPSEC 1848 /* compute ESP/AH header size for TCP, including outer IP header. */ 1849 size_t 1850 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1851 { 1852 struct inpcb *inp; 1853 struct mbuf *m; 1854 size_t hdrsiz; 1855 struct ip *ip; 1856 #ifdef INET6 1857 struct ip6_hdr *ip6; 1858 #endif 1859 struct tcphdr *th; 1860 1861 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1862 return (0); 1863 m = m_gethdr(M_NOWAIT, MT_DATA); 1864 if (!m) 1865 return (0); 1866 1867 #ifdef INET6 1868 if ((inp->inp_vflag & INP_IPV6) != 0) { 1869 ip6 = mtod(m, struct ip6_hdr *); 1870 th = (struct tcphdr *)(ip6 + 1); 1871 m->m_pkthdr.len = m->m_len = 1872 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1873 tcpip_fillheaders(inp, ip6, th); 1874 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1875 } else 1876 #endif /* INET6 */ 1877 { 1878 ip = mtod(m, struct ip *); 1879 th = (struct tcphdr *)(ip + 1); 1880 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1881 tcpip_fillheaders(inp, ip, th); 1882 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1883 } 1884 1885 m_free(m); 1886 return (hdrsiz); 1887 } 1888 #endif /* IPSEC */ 1889 1890 #ifdef TCP_SIGNATURE 1891 /* 1892 * Callback function invoked by m_apply() to digest TCP segment data 1893 * contained within an mbuf chain. 1894 */ 1895 static int 1896 tcp_signature_apply(void *fstate, void *data, u_int len) 1897 { 1898 1899 MD5Update(fstate, (u_char *)data, len); 1900 return (0); 1901 } 1902 1903 /* 1904 * Compute TCP-MD5 hash of a TCP segment. (RFC2385) 1905 * 1906 * Parameters: 1907 * m pointer to head of mbuf chain 1908 * _unused 1909 * len length of TCP segment data, excluding options 1910 * optlen length of TCP segment options 1911 * buf pointer to storage for computed MD5 digest 1912 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 1913 * 1914 * We do this over ip, tcphdr, segment data, and the key in the SADB. 1915 * When called from tcp_input(), we can be sure that th_sum has been 1916 * zeroed out and verified already. 1917 * 1918 * Return 0 if successful, otherwise return -1. 1919 * 1920 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 1921 * search with the destination IP address, and a 'magic SPI' to be 1922 * determined by the application. This is hardcoded elsewhere to 1179 1923 * right now. Another branch of this code exists which uses the SPD to 1924 * specify per-application flows but it is unstable. 1925 */ 1926 int 1927 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen, 1928 u_char *buf, u_int direction) 1929 { 1930 union sockaddr_union dst; 1931 #ifdef INET 1932 struct ippseudo ippseudo; 1933 #endif 1934 MD5_CTX ctx; 1935 int doff; 1936 struct ip *ip; 1937 #ifdef INET 1938 struct ipovly *ipovly; 1939 #endif 1940 struct secasvar *sav; 1941 struct tcphdr *th; 1942 #ifdef INET6 1943 struct ip6_hdr *ip6; 1944 struct in6_addr in6; 1945 char ip6buf[INET6_ADDRSTRLEN]; 1946 uint32_t plen; 1947 uint16_t nhdr; 1948 #endif 1949 u_short savecsum; 1950 1951 KASSERT(m != NULL, ("NULL mbuf chain")); 1952 KASSERT(buf != NULL, ("NULL signature pointer")); 1953 1954 /* Extract the destination from the IP header in the mbuf. */ 1955 bzero(&dst, sizeof(union sockaddr_union)); 1956 ip = mtod(m, struct ip *); 1957 #ifdef INET6 1958 ip6 = NULL; /* Make the compiler happy. */ 1959 #endif 1960 switch (ip->ip_v) { 1961 #ifdef INET 1962 case IPVERSION: 1963 dst.sa.sa_len = sizeof(struct sockaddr_in); 1964 dst.sa.sa_family = AF_INET; 1965 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 1966 ip->ip_src : ip->ip_dst; 1967 break; 1968 #endif 1969 #ifdef INET6 1970 case (IPV6_VERSION >> 4): 1971 ip6 = mtod(m, struct ip6_hdr *); 1972 dst.sa.sa_len = sizeof(struct sockaddr_in6); 1973 dst.sa.sa_family = AF_INET6; 1974 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ? 1975 ip6->ip6_src : ip6->ip6_dst; 1976 break; 1977 #endif 1978 default: 1979 return (EINVAL); 1980 /* NOTREACHED */ 1981 break; 1982 } 1983 1984 /* Look up an SADB entry which matches the address of the peer. */ 1985 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 1986 if (sav == NULL) { 1987 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__, 1988 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) : 1989 #ifdef INET6 1990 (ip->ip_v == (IPV6_VERSION >> 4)) ? 1991 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) : 1992 #endif 1993 "(unsupported)")); 1994 return (EINVAL); 1995 } 1996 1997 MD5Init(&ctx); 1998 /* 1999 * Step 1: Update MD5 hash with IP(v6) pseudo-header. 2000 * 2001 * XXX The ippseudo header MUST be digested in network byte order, 2002 * or else we'll fail the regression test. Assume all fields we've 2003 * been doing arithmetic on have been in host byte order. 2004 * XXX One cannot depend on ipovly->ih_len here. When called from 2005 * tcp_output(), the underlying ip_len member has not yet been set. 2006 */ 2007 switch (ip->ip_v) { 2008 #ifdef INET 2009 case IPVERSION: 2010 ipovly = (struct ipovly *)ip; 2011 ippseudo.ippseudo_src = ipovly->ih_src; 2012 ippseudo.ippseudo_dst = ipovly->ih_dst; 2013 ippseudo.ippseudo_pad = 0; 2014 ippseudo.ippseudo_p = IPPROTO_TCP; 2015 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + 2016 optlen); 2017 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2018 2019 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip)); 2020 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen; 2021 break; 2022 #endif 2023 #ifdef INET6 2024 /* 2025 * RFC 2385, 2.0 Proposal 2026 * For IPv6, the pseudo-header is as described in RFC 2460, namely the 2027 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero- 2028 * extended next header value (to form 32 bits), and 32-bit segment 2029 * length. 2030 * Note: Upper-Layer Packet Length comes before Next Header. 2031 */ 2032 case (IPV6_VERSION >> 4): 2033 in6 = ip6->ip6_src; 2034 in6_clearscope(&in6); 2035 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2036 in6 = ip6->ip6_dst; 2037 in6_clearscope(&in6); 2038 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2039 plen = htonl(len + sizeof(struct tcphdr) + optlen); 2040 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t)); 2041 nhdr = 0; 2042 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2043 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2044 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2045 nhdr = IPPROTO_TCP; 2046 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2047 2048 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr)); 2049 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen; 2050 break; 2051 #endif 2052 default: 2053 return (EINVAL); 2054 /* NOTREACHED */ 2055 break; 2056 } 2057 2058 2059 /* 2060 * Step 2: Update MD5 hash with TCP header, excluding options. 2061 * The TCP checksum must be set to zero. 2062 */ 2063 savecsum = th->th_sum; 2064 th->th_sum = 0; 2065 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2066 th->th_sum = savecsum; 2067 2068 /* 2069 * Step 3: Update MD5 hash with TCP segment data. 2070 * Use m_apply() to avoid an early m_pullup(). 2071 */ 2072 if (len > 0) 2073 m_apply(m, doff, len, tcp_signature_apply, &ctx); 2074 2075 /* 2076 * Step 4: Update MD5 hash with shared secret. 2077 */ 2078 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 2079 MD5Final(buf, &ctx); 2080 2081 key_sa_recordxfer(sav, m); 2082 KEY_FREESAV(&sav); 2083 return (0); 2084 } 2085 2086 /* 2087 * Verify the TCP-MD5 hash of a TCP segment. (RFC2385) 2088 * 2089 * Parameters: 2090 * m pointer to head of mbuf chain 2091 * len length of TCP segment data, excluding options 2092 * optlen length of TCP segment options 2093 * buf pointer to storage for computed MD5 digest 2094 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 2095 * 2096 * Return 1 if successful, otherwise return 0. 2097 */ 2098 int 2099 tcp_signature_verify(struct mbuf *m, int off0, int tlen, int optlen, 2100 struct tcpopt *to, struct tcphdr *th, u_int tcpbflag) 2101 { 2102 char tmpdigest[TCP_SIGLEN]; 2103 2104 if (tcp_sig_checksigs == 0) 2105 return (1); 2106 if ((tcpbflag & TF_SIGNATURE) == 0) { 2107 if ((to->to_flags & TOF_SIGNATURE) != 0) { 2108 2109 /* 2110 * If this socket is not expecting signature but 2111 * the segment contains signature just fail. 2112 */ 2113 TCPSTAT_INC(tcps_sig_err_sigopt); 2114 TCPSTAT_INC(tcps_sig_rcvbadsig); 2115 return (0); 2116 } 2117 2118 /* Signature is not expected, and not present in segment. */ 2119 return (1); 2120 } 2121 2122 /* 2123 * If this socket is expecting signature but the segment does not 2124 * contain any just fail. 2125 */ 2126 if ((to->to_flags & TOF_SIGNATURE) == 0) { 2127 TCPSTAT_INC(tcps_sig_err_nosigopt); 2128 TCPSTAT_INC(tcps_sig_rcvbadsig); 2129 return (0); 2130 } 2131 if (tcp_signature_compute(m, off0, tlen, optlen, &tmpdigest[0], 2132 IPSEC_DIR_INBOUND) == -1) { 2133 TCPSTAT_INC(tcps_sig_err_buildsig); 2134 TCPSTAT_INC(tcps_sig_rcvbadsig); 2135 return (0); 2136 } 2137 2138 if (bcmp(to->to_signature, &tmpdigest[0], TCP_SIGLEN) != 0) { 2139 TCPSTAT_INC(tcps_sig_rcvbadsig); 2140 return (0); 2141 } 2142 TCPSTAT_INC(tcps_sig_rcvgoodsig); 2143 return (1); 2144 } 2145 #endif /* TCP_SIGNATURE */ 2146 2147 static int 2148 sysctl_drop(SYSCTL_HANDLER_ARGS) 2149 { 2150 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 2151 struct sockaddr_storage addrs[2]; 2152 struct inpcb *inp; 2153 struct tcpcb *tp; 2154 struct tcptw *tw; 2155 struct sockaddr_in *fin, *lin; 2156 #ifdef INET6 2157 struct sockaddr_in6 *fin6, *lin6; 2158 #endif 2159 int error; 2160 2161 inp = NULL; 2162 fin = lin = NULL; 2163 #ifdef INET6 2164 fin6 = lin6 = NULL; 2165 #endif 2166 error = 0; 2167 2168 if (req->oldptr != NULL || req->oldlen != 0) 2169 return (EINVAL); 2170 if (req->newptr == NULL) 2171 return (EPERM); 2172 if (req->newlen < sizeof(addrs)) 2173 return (ENOMEM); 2174 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2175 if (error) 2176 return (error); 2177 2178 switch (addrs[0].ss_family) { 2179 #ifdef INET6 2180 case AF_INET6: 2181 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2182 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2183 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2184 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2185 return (EINVAL); 2186 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2187 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2188 return (EINVAL); 2189 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2190 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2191 fin = (struct sockaddr_in *)&addrs[0]; 2192 lin = (struct sockaddr_in *)&addrs[1]; 2193 break; 2194 } 2195 error = sa6_embedscope(fin6, V_ip6_use_defzone); 2196 if (error) 2197 return (error); 2198 error = sa6_embedscope(lin6, V_ip6_use_defzone); 2199 if (error) 2200 return (error); 2201 break; 2202 #endif 2203 #ifdef INET 2204 case AF_INET: 2205 fin = (struct sockaddr_in *)&addrs[0]; 2206 lin = (struct sockaddr_in *)&addrs[1]; 2207 if (fin->sin_len != sizeof(struct sockaddr_in) || 2208 lin->sin_len != sizeof(struct sockaddr_in)) 2209 return (EINVAL); 2210 break; 2211 #endif 2212 default: 2213 return (EINVAL); 2214 } 2215 INP_INFO_WLOCK(&V_tcbinfo); 2216 switch (addrs[0].ss_family) { 2217 #ifdef INET6 2218 case AF_INET6: 2219 inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr, 2220 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port, 2221 INPLOOKUP_WLOCKPCB, NULL); 2222 break; 2223 #endif 2224 #ifdef INET 2225 case AF_INET: 2226 inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port, 2227 lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL); 2228 break; 2229 #endif 2230 } 2231 if (inp != NULL) { 2232 if (inp->inp_flags & INP_TIMEWAIT) { 2233 /* 2234 * XXXRW: There currently exists a state where an 2235 * inpcb is present, but its timewait state has been 2236 * discarded. For now, don't allow dropping of this 2237 * type of inpcb. 2238 */ 2239 tw = intotw(inp); 2240 if (tw != NULL) 2241 tcp_twclose(tw, 0); 2242 else 2243 INP_WUNLOCK(inp); 2244 } else if (!(inp->inp_flags & INP_DROPPED) && 2245 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2246 tp = intotcpcb(inp); 2247 tp = tcp_drop(tp, ECONNABORTED); 2248 if (tp != NULL) 2249 INP_WUNLOCK(inp); 2250 } else 2251 INP_WUNLOCK(inp); 2252 } else 2253 error = ESRCH; 2254 INP_INFO_WUNLOCK(&V_tcbinfo); 2255 return (error); 2256 } 2257 2258 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2259 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2260 0, sysctl_drop, "", "Drop TCP connection"); 2261 2262 /* 2263 * Generate a standardized TCP log line for use throughout the 2264 * tcp subsystem. Memory allocation is done with M_NOWAIT to 2265 * allow use in the interrupt context. 2266 * 2267 * NB: The caller MUST free(s, M_TCPLOG) the returned string. 2268 * NB: The function may return NULL if memory allocation failed. 2269 * 2270 * Due to header inclusion and ordering limitations the struct ip 2271 * and ip6_hdr pointers have to be passed as void pointers. 2272 */ 2273 char * 2274 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2275 const void *ip6hdr) 2276 { 2277 2278 /* Is logging enabled? */ 2279 if (tcp_log_in_vain == 0) 2280 return (NULL); 2281 2282 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr)); 2283 } 2284 2285 char * 2286 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2287 const void *ip6hdr) 2288 { 2289 2290 /* Is logging enabled? */ 2291 if (tcp_log_debug == 0) 2292 return (NULL); 2293 2294 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr)); 2295 } 2296 2297 static char * 2298 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2299 const void *ip6hdr) 2300 { 2301 char *s, *sp; 2302 size_t size; 2303 struct ip *ip; 2304 #ifdef INET6 2305 const struct ip6_hdr *ip6; 2306 2307 ip6 = (const struct ip6_hdr *)ip6hdr; 2308 #endif /* INET6 */ 2309 ip = (struct ip *)ip4hdr; 2310 2311 /* 2312 * The log line looks like this: 2313 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>" 2314 */ 2315 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") + 2316 sizeof(PRINT_TH_FLAGS) + 1 + 2317 #ifdef INET6 2318 2 * INET6_ADDRSTRLEN; 2319 #else 2320 2 * INET_ADDRSTRLEN; 2321 #endif /* INET6 */ 2322 2323 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT); 2324 if (s == NULL) 2325 return (NULL); 2326 2327 strcat(s, "TCP: ["); 2328 sp = s + strlen(s); 2329 2330 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) { 2331 inet_ntoa_r(inc->inc_faddr, sp); 2332 sp = s + strlen(s); 2333 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2334 sp = s + strlen(s); 2335 inet_ntoa_r(inc->inc_laddr, sp); 2336 sp = s + strlen(s); 2337 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2338 #ifdef INET6 2339 } else if (inc) { 2340 ip6_sprintf(sp, &inc->inc6_faddr); 2341 sp = s + strlen(s); 2342 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2343 sp = s + strlen(s); 2344 ip6_sprintf(sp, &inc->inc6_laddr); 2345 sp = s + strlen(s); 2346 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2347 } else if (ip6 && th) { 2348 ip6_sprintf(sp, &ip6->ip6_src); 2349 sp = s + strlen(s); 2350 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2351 sp = s + strlen(s); 2352 ip6_sprintf(sp, &ip6->ip6_dst); 2353 sp = s + strlen(s); 2354 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2355 #endif /* INET6 */ 2356 #ifdef INET 2357 } else if (ip && th) { 2358 inet_ntoa_r(ip->ip_src, sp); 2359 sp = s + strlen(s); 2360 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2361 sp = s + strlen(s); 2362 inet_ntoa_r(ip->ip_dst, sp); 2363 sp = s + strlen(s); 2364 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2365 #endif /* INET */ 2366 } else { 2367 free(s, M_TCPLOG); 2368 return (NULL); 2369 } 2370 sp = s + strlen(s); 2371 if (th) 2372 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS); 2373 if (*(s + size - 1) != '\0') 2374 panic("%s: string too long", __func__); 2375 return (s); 2376 } 2377