Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet/tcp_subr.c
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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: releng/8.2/sys/netinet/tcp_subr.c 214860 2010-11-06 09:42:41Z lstewart $"); 34 35 #include "opt_compat.h" 36 #include "opt_inet.h" 37 #include "opt_inet6.h" 38 #include "opt_ipsec.h" 39 #include "opt_tcpdebug.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/callout.h> 44 #include <sys/kernel.h> 45 #include <sys/sysctl.h> 46 #include <sys/jail.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 59 #include <vm/uma.h> 60 61 #include <net/route.h> 62 #include <net/if.h> 63 #include <net/vnet.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 <netinet6/ip6protosw.h> 98 99 #ifdef IPSEC 100 #include <netipsec/ipsec.h> 101 #include <netipsec/xform.h> 102 #ifdef INET6 103 #include <netipsec/ipsec6.h> 104 #endif 105 #include <netipsec/key.h> 106 #include <sys/syslog.h> 107 #endif /*IPSEC*/ 108 109 #include <machine/in_cksum.h> 110 #include <sys/md5.h> 111 112 #include <security/mac/mac_framework.h> 113 114 VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS; 115 #ifdef INET6 116 VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS; 117 #endif 118 119 static int 120 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS) 121 { 122 int error, new; 123 124 new = V_tcp_mssdflt; 125 error = sysctl_handle_int(oidp, &new, 0, req); 126 if (error == 0 && req->newptr) { 127 if (new < TCP_MINMSS) 128 error = EINVAL; 129 else 130 V_tcp_mssdflt = new; 131 } 132 return (error); 133 } 134 135 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, 136 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_mssdflt), 0, 137 &sysctl_net_inet_tcp_mss_check, "I", 138 "Default TCP Maximum Segment Size"); 139 140 #ifdef INET6 141 static int 142 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS) 143 { 144 int error, new; 145 146 new = V_tcp_v6mssdflt; 147 error = sysctl_handle_int(oidp, &new, 0, req); 148 if (error == 0 && req->newptr) { 149 if (new < TCP_MINMSS) 150 error = EINVAL; 151 else 152 V_tcp_v6mssdflt = new; 153 } 154 return (error); 155 } 156 157 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 158 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_v6mssdflt), 0, 159 &sysctl_net_inet_tcp_mss_v6_check, "I", 160 "Default TCP Maximum Segment Size for IPv6"); 161 #endif 162 163 static int 164 vnet_sysctl_msec_to_ticks(SYSCTL_HANDLER_ARGS) 165 { 166 167 VNET_SYSCTL_ARG(req, arg1); 168 return (sysctl_msec_to_ticks(oidp, arg1, arg2, req)); 169 } 170 171 /* 172 * Minimum MSS we accept and use. This prevents DoS attacks where 173 * we are forced to a ridiculous low MSS like 20 and send hundreds 174 * of packets instead of one. The effect scales with the available 175 * bandwidth and quickly saturates the CPU and network interface 176 * with packet generation and sending. Set to zero to disable MINMSS 177 * checking. This setting prevents us from sending too small packets. 178 */ 179 VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS; 180 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 181 &VNET_NAME(tcp_minmss), 0, 182 "Minmum TCP Maximum Segment Size"); 183 184 VNET_DEFINE(int, tcp_do_rfc1323) = 1; 185 SYSCTL_VNET_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 186 &VNET_NAME(tcp_do_rfc1323), 0, 187 "Enable rfc1323 (high performance TCP) extensions"); 188 189 static int tcp_log_debug = 0; 190 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW, 191 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments"); 192 193 static int tcp_tcbhashsize = 0; 194 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 195 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 196 197 static int do_tcpdrain = 1; 198 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 199 "Enable tcp_drain routine for extra help when low on mbufs"); 200 201 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 202 &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs"); 203 204 static VNET_DEFINE(int, icmp_may_rst) = 1; 205 #define V_icmp_may_rst VNET(icmp_may_rst) 206 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, 207 &VNET_NAME(icmp_may_rst), 0, 208 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 209 210 static VNET_DEFINE(int, tcp_isn_reseed_interval) = 0; 211 #define V_tcp_isn_reseed_interval VNET(tcp_isn_reseed_interval) 212 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 213 &VNET_NAME(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 static VNET_DEFINE(int, tcp_inflight_enable) = 0; 225 #define V_tcp_inflight_enable VNET(tcp_inflight_enable) 226 SYSCTL_VNET_INT(_net_inet_tcp_inflight, OID_AUTO, enable, CTLFLAG_RW, 227 &VNET_NAME(tcp_inflight_enable), 0, 228 "Enable automatic TCP inflight data limiting"); 229 230 static int tcp_inflight_debug = 0; 231 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW, 232 &tcp_inflight_debug, 0, 233 "Debug TCP inflight calculations"); 234 235 static VNET_DEFINE(int, tcp_inflight_rttthresh); 236 #define V_tcp_inflight_rttthresh VNET(tcp_inflight_rttthresh) 237 SYSCTL_VNET_PROC(_net_inet_tcp_inflight, OID_AUTO, rttthresh, 238 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_inflight_rttthresh), 0, 239 vnet_sysctl_msec_to_ticks, "I", 240 "RTT threshold below which inflight will deactivate itself"); 241 242 static VNET_DEFINE(int, tcp_inflight_min) = 6144; 243 #define V_tcp_inflight_min VNET(tcp_inflight_min) 244 SYSCTL_VNET_INT(_net_inet_tcp_inflight, OID_AUTO, min, CTLFLAG_RW, 245 &VNET_NAME(tcp_inflight_min), 0, 246 "Lower-bound for TCP inflight window"); 247 248 static VNET_DEFINE(int, tcp_inflight_max) = TCP_MAXWIN << TCP_MAX_WINSHIFT; 249 #define V_tcp_inflight_max VNET(tcp_inflight_max) 250 SYSCTL_VNET_INT(_net_inet_tcp_inflight, OID_AUTO, max, CTLFLAG_RW, 251 &VNET_NAME(tcp_inflight_max), 0, 252 "Upper-bound for TCP inflight window"); 253 254 static VNET_DEFINE(int, tcp_inflight_stab) = 20; 255 #define V_tcp_inflight_stab VNET(tcp_inflight_stab) 256 SYSCTL_VNET_INT(_net_inet_tcp_inflight, OID_AUTO, stab, CTLFLAG_RW, 257 &VNET_NAME(tcp_inflight_stab), 0, 258 "Inflight Algorithm Stabilization 20 = 2 packets"); 259 260 VNET_DEFINE(uma_zone_t, sack_hole_zone); 261 #define V_sack_hole_zone VNET(sack_hole_zone) 262 263 static struct inpcb *tcp_notify(struct inpcb *, int); 264 static void tcp_isn_tick(void *); 265 static char * tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, 266 void *ip4hdr, const void *ip6hdr); 267 268 /* 269 * Target size of TCP PCB hash tables. Must be a power of two. 270 * 271 * Note that this can be overridden by the kernel environment 272 * variable net.inet.tcp.tcbhashsize 273 */ 274 #ifndef TCBHASHSIZE 275 #define TCBHASHSIZE 512 276 #endif 277 278 /* 279 * XXX 280 * Callouts should be moved into struct tcp directly. They are currently 281 * separate because the tcpcb structure is exported to userland for sysctl 282 * parsing purposes, which do not know about callouts. 283 */ 284 struct tcpcb_mem { 285 struct tcpcb tcb; 286 struct tcp_timer tt; 287 }; 288 289 static VNET_DEFINE(uma_zone_t, tcpcb_zone); 290 #define V_tcpcb_zone VNET(tcpcb_zone) 291 292 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers"); 293 struct callout isn_callout; 294 static struct mtx isn_mtx; 295 296 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 297 #define ISN_LOCK() mtx_lock(&isn_mtx) 298 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 299 300 /* 301 * TCP initialization. 302 */ 303 static void 304 tcp_zone_change(void *tag) 305 { 306 307 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 308 uma_zone_set_max(V_tcpcb_zone, maxsockets); 309 tcp_tw_zone_change(); 310 } 311 312 static int 313 tcp_inpcb_init(void *mem, int size, int flags) 314 { 315 struct inpcb *inp = mem; 316 317 INP_LOCK_INIT(inp, "inp", "tcpinp"); 318 return (0); 319 } 320 321 void 322 tcp_init(void) 323 { 324 int hashsize; 325 326 INP_INFO_LOCK_INIT(&V_tcbinfo, "tcp"); 327 LIST_INIT(&V_tcb); 328 #ifdef VIMAGE 329 V_tcbinfo.ipi_vnet = curvnet; 330 #endif 331 V_tcbinfo.ipi_listhead = &V_tcb; 332 hashsize = TCBHASHSIZE; 333 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 334 if (!powerof2(hashsize)) { 335 printf("WARNING: TCB hash size not a power of 2\n"); 336 hashsize = 512; /* safe default */ 337 } 338 V_tcbinfo.ipi_hashbase = hashinit(hashsize, M_PCB, 339 &V_tcbinfo.ipi_hashmask); 340 V_tcbinfo.ipi_porthashbase = hashinit(hashsize, M_PCB, 341 &V_tcbinfo.ipi_porthashmask); 342 V_tcbinfo.ipi_zone = uma_zcreate("tcp_inpcb", sizeof(struct inpcb), 343 NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 344 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 345 V_tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 346 347 /* 348 * These have to be type stable for the benefit of the timers. 349 */ 350 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 351 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 352 uma_zone_set_max(V_tcpcb_zone, maxsockets); 353 354 tcp_tw_init(); 355 syncache_init(); 356 tcp_hc_init(); 357 tcp_reass_init(); 358 359 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack); 360 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 361 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 362 363 /* Skip initialization of globals for non-default instances. */ 364 if (!IS_DEFAULT_VNET(curvnet)) 365 return; 366 367 /* XXX virtualize those bellow? */ 368 tcp_delacktime = TCPTV_DELACK; 369 tcp_keepinit = TCPTV_KEEP_INIT; 370 tcp_keepidle = TCPTV_KEEP_IDLE; 371 tcp_keepintvl = TCPTV_KEEPINTVL; 372 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 373 tcp_msl = TCPTV_MSL; 374 tcp_rexmit_min = TCPTV_MIN; 375 if (tcp_rexmit_min < 1) 376 tcp_rexmit_min = 1; 377 tcp_rexmit_slop = TCPTV_CPU_VAR; 378 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 379 tcp_tcbhashsize = hashsize; 380 381 #ifdef INET6 382 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 383 #else /* INET6 */ 384 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 385 #endif /* INET6 */ 386 if (max_protohdr < TCP_MINPROTOHDR) 387 max_protohdr = TCP_MINPROTOHDR; 388 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 389 panic("tcp_init"); 390 #undef TCP_MINPROTOHDR 391 392 ISN_LOCK_INIT(); 393 callout_init(&isn_callout, CALLOUT_MPSAFE); 394 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 395 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 396 SHUTDOWN_PRI_DEFAULT); 397 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 398 EVENTHANDLER_PRI_ANY); 399 } 400 401 #ifdef VIMAGE 402 void 403 tcp_destroy(void) 404 { 405 406 tcp_reass_destroy(); 407 tcp_hc_destroy(); 408 syncache_destroy(); 409 tcp_tw_destroy(); 410 411 /* XXX check that hashes are empty! */ 412 hashdestroy(V_tcbinfo.ipi_hashbase, M_PCB, 413 V_tcbinfo.ipi_hashmask); 414 hashdestroy(V_tcbinfo.ipi_porthashbase, M_PCB, 415 V_tcbinfo.ipi_porthashmask); 416 417 uma_zdestroy(V_sack_hole_zone); 418 uma_zdestroy(V_tcpcb_zone); 419 uma_zdestroy(V_tcbinfo.ipi_zone); 420 421 INP_INFO_LOCK_DESTROY(&V_tcbinfo); 422 } 423 #endif 424 425 void 426 tcp_fini(void *xtp) 427 { 428 429 callout_stop(&isn_callout); 430 } 431 432 /* 433 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 434 * tcp_template used to store this data in mbufs, but we now recopy it out 435 * of the tcpcb each time to conserve mbufs. 436 */ 437 void 438 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 439 { 440 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 441 442 INP_WLOCK_ASSERT(inp); 443 444 #ifdef INET6 445 if ((inp->inp_vflag & INP_IPV6) != 0) { 446 struct ip6_hdr *ip6; 447 448 ip6 = (struct ip6_hdr *)ip_ptr; 449 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 450 (inp->inp_flow & IPV6_FLOWINFO_MASK); 451 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 452 (IPV6_VERSION & IPV6_VERSION_MASK); 453 ip6->ip6_nxt = IPPROTO_TCP; 454 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 455 ip6->ip6_src = inp->in6p_laddr; 456 ip6->ip6_dst = inp->in6p_faddr; 457 } else 458 #endif 459 { 460 struct ip *ip; 461 462 ip = (struct ip *)ip_ptr; 463 ip->ip_v = IPVERSION; 464 ip->ip_hl = 5; 465 ip->ip_tos = inp->inp_ip_tos; 466 ip->ip_len = 0; 467 ip->ip_id = 0; 468 ip->ip_off = 0; 469 ip->ip_ttl = inp->inp_ip_ttl; 470 ip->ip_sum = 0; 471 ip->ip_p = IPPROTO_TCP; 472 ip->ip_src = inp->inp_laddr; 473 ip->ip_dst = inp->inp_faddr; 474 } 475 th->th_sport = inp->inp_lport; 476 th->th_dport = inp->inp_fport; 477 th->th_seq = 0; 478 th->th_ack = 0; 479 th->th_x2 = 0; 480 th->th_off = 5; 481 th->th_flags = 0; 482 th->th_win = 0; 483 th->th_urp = 0; 484 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 485 } 486 487 /* 488 * Create template to be used to send tcp packets on a connection. 489 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 490 * use for this function is in keepalives, which use tcp_respond. 491 */ 492 struct tcptemp * 493 tcpip_maketemplate(struct inpcb *inp) 494 { 495 struct tcptemp *t; 496 497 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT); 498 if (t == NULL) 499 return (NULL); 500 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t); 501 return (t); 502 } 503 504 /* 505 * Send a single message to the TCP at address specified by 506 * the given TCP/IP header. If m == NULL, then we make a copy 507 * of the tcpiphdr at ti and send directly to the addressed host. 508 * This is used to force keep alive messages out using the TCP 509 * template for a connection. If flags are given then we send 510 * a message back to the TCP which originated the * segment ti, 511 * and discard the mbuf containing it and any other attached mbufs. 512 * 513 * In any case the ack and sequence number of the transmitted 514 * segment are as specified by the parameters. 515 * 516 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 517 */ 518 void 519 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 520 tcp_seq ack, tcp_seq seq, int flags) 521 { 522 int tlen; 523 int win = 0; 524 struct ip *ip; 525 struct tcphdr *nth; 526 #ifdef INET6 527 struct ip6_hdr *ip6; 528 int isipv6; 529 #endif /* INET6 */ 530 int ipflags = 0; 531 struct inpcb *inp; 532 533 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 534 535 #ifdef INET6 536 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 537 ip6 = ipgen; 538 #endif /* INET6 */ 539 ip = ipgen; 540 541 if (tp != NULL) { 542 inp = tp->t_inpcb; 543 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 544 INP_WLOCK_ASSERT(inp); 545 } else 546 inp = NULL; 547 548 if (tp != NULL) { 549 if (!(flags & TH_RST)) { 550 win = sbspace(&inp->inp_socket->so_rcv); 551 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 552 win = (long)TCP_MAXWIN << tp->rcv_scale; 553 } 554 } 555 if (m == NULL) { 556 m = m_gethdr(M_DONTWAIT, MT_DATA); 557 if (m == NULL) 558 return; 559 tlen = 0; 560 m->m_data += max_linkhdr; 561 #ifdef INET6 562 if (isipv6) { 563 bcopy((caddr_t)ip6, mtod(m, caddr_t), 564 sizeof(struct ip6_hdr)); 565 ip6 = mtod(m, struct ip6_hdr *); 566 nth = (struct tcphdr *)(ip6 + 1); 567 } else 568 #endif /* INET6 */ 569 { 570 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 571 ip = mtod(m, struct ip *); 572 nth = (struct tcphdr *)(ip + 1); 573 } 574 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 575 flags = TH_ACK; 576 } else { 577 /* 578 * reuse the mbuf. 579 * XXX MRT We inherrit the FIB, which is lucky. 580 */ 581 m_freem(m->m_next); 582 m->m_next = NULL; 583 m->m_data = (caddr_t)ipgen; 584 /* m_len is set later */ 585 tlen = 0; 586 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 587 #ifdef INET6 588 if (isipv6) { 589 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 590 nth = (struct tcphdr *)(ip6 + 1); 591 } else 592 #endif /* INET6 */ 593 { 594 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t); 595 nth = (struct tcphdr *)(ip + 1); 596 } 597 if (th != nth) { 598 /* 599 * this is usually a case when an extension header 600 * exists between the IPv6 header and the 601 * TCP header. 602 */ 603 nth->th_sport = th->th_sport; 604 nth->th_dport = th->th_dport; 605 } 606 xchg(nth->th_dport, nth->th_sport, uint16_t); 607 #undef xchg 608 } 609 #ifdef INET6 610 if (isipv6) { 611 ip6->ip6_flow = 0; 612 ip6->ip6_vfc = IPV6_VERSION; 613 ip6->ip6_nxt = IPPROTO_TCP; 614 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 615 tlen)); 616 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 617 } else 618 #endif 619 { 620 tlen += sizeof (struct tcpiphdr); 621 ip->ip_len = tlen; 622 ip->ip_ttl = V_ip_defttl; 623 if (V_path_mtu_discovery) 624 ip->ip_off |= IP_DF; 625 } 626 m->m_len = tlen; 627 m->m_pkthdr.len = tlen; 628 m->m_pkthdr.rcvif = NULL; 629 #ifdef MAC 630 if (inp != NULL) { 631 /* 632 * Packet is associated with a socket, so allow the 633 * label of the response to reflect the socket label. 634 */ 635 INP_WLOCK_ASSERT(inp); 636 mac_inpcb_create_mbuf(inp, m); 637 } else { 638 /* 639 * Packet is not associated with a socket, so possibly 640 * update the label in place. 641 */ 642 mac_netinet_tcp_reply(m); 643 } 644 #endif 645 nth->th_seq = htonl(seq); 646 nth->th_ack = htonl(ack); 647 nth->th_x2 = 0; 648 nth->th_off = sizeof (struct tcphdr) >> 2; 649 nth->th_flags = flags; 650 if (tp != NULL) 651 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 652 else 653 nth->th_win = htons((u_short)win); 654 nth->th_urp = 0; 655 #ifdef INET6 656 if (isipv6) { 657 nth->th_sum = 0; 658 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 659 sizeof(struct ip6_hdr), 660 tlen - sizeof(struct ip6_hdr)); 661 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 662 NULL, NULL); 663 } else 664 #endif /* INET6 */ 665 { 666 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 667 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 668 m->m_pkthdr.csum_flags = CSUM_TCP; 669 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 670 } 671 #ifdef TCPDEBUG 672 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 673 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 674 #endif 675 #ifdef INET6 676 if (isipv6) 677 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 678 else 679 #endif /* INET6 */ 680 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 681 } 682 683 /* 684 * Create a new TCP control block, making an 685 * empty reassembly queue and hooking it to the argument 686 * protocol control block. The `inp' parameter must have 687 * come from the zone allocator set up in tcp_init(). 688 */ 689 struct tcpcb * 690 tcp_newtcpcb(struct inpcb *inp) 691 { 692 struct tcpcb_mem *tm; 693 struct tcpcb *tp; 694 #ifdef INET6 695 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 696 #endif /* INET6 */ 697 698 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO); 699 if (tm == NULL) 700 return (NULL); 701 tp = &tm->tcb; 702 #ifdef VIMAGE 703 tp->t_vnet = inp->inp_vnet; 704 #endif 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 struct socket *so = tp->t_inpcb->inp_socket; 759 760 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 761 INP_WLOCK_ASSERT(tp->t_inpcb); 762 763 if (TCPS_HAVERCVDSYN(tp->t_state)) { 764 tp->t_state = TCPS_CLOSED; 765 (void) tcp_output_reset(tp); 766 TCPSTAT_INC(tcps_drops); 767 } else 768 TCPSTAT_INC(tcps_conndrops); 769 if (errno == ETIMEDOUT && tp->t_softerror) 770 errno = tp->t_softerror; 771 so->so_error = errno; 772 return (tcp_close(tp)); 773 } 774 775 void 776 tcp_discardcb(struct tcpcb *tp) 777 { 778 struct inpcb *inp = tp->t_inpcb; 779 struct socket *so = inp->inp_socket; 780 #ifdef INET6 781 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 782 #endif /* INET6 */ 783 784 INP_WLOCK_ASSERT(inp); 785 786 /* 787 * Make sure that all of our timers are stopped before we 788 * delete the PCB. 789 */ 790 callout_stop(&tp->t_timers->tt_rexmt); 791 callout_stop(&tp->t_timers->tt_persist); 792 callout_stop(&tp->t_timers->tt_keep); 793 callout_stop(&tp->t_timers->tt_2msl); 794 callout_stop(&tp->t_timers->tt_delack); 795 796 /* 797 * If we got enough samples through the srtt filter, 798 * save the rtt and rttvar in the routing entry. 799 * 'Enough' is arbitrarily defined as 4 rtt samples. 800 * 4 samples is enough for the srtt filter to converge 801 * to within enough % of the correct value; fewer samples 802 * and we could save a bogus rtt. The danger is not high 803 * as tcp quickly recovers from everything. 804 * XXX: Works very well but needs some more statistics! 805 */ 806 if (tp->t_rttupdated >= 4) { 807 struct hc_metrics_lite metrics; 808 u_long ssthresh; 809 810 bzero(&metrics, sizeof(metrics)); 811 /* 812 * Update the ssthresh always when the conditions below 813 * are satisfied. This gives us better new start value 814 * for the congestion avoidance for new connections. 815 * ssthresh is only set if packet loss occured on a session. 816 * 817 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 818 * being torn down. Ideally this code would not use 'so'. 819 */ 820 ssthresh = tp->snd_ssthresh; 821 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 822 /* 823 * convert the limit from user data bytes to 824 * packets then to packet data bytes. 825 */ 826 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 827 if (ssthresh < 2) 828 ssthresh = 2; 829 ssthresh *= (u_long)(tp->t_maxseg + 830 #ifdef INET6 831 (isipv6 ? sizeof (struct ip6_hdr) + 832 sizeof (struct tcphdr) : 833 #endif 834 sizeof (struct tcpiphdr) 835 #ifdef INET6 836 ) 837 #endif 838 ); 839 } else 840 ssthresh = 0; 841 metrics.rmx_ssthresh = ssthresh; 842 843 metrics.rmx_rtt = tp->t_srtt; 844 metrics.rmx_rttvar = tp->t_rttvar; 845 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 846 metrics.rmx_bandwidth = tp->snd_bandwidth; 847 metrics.rmx_cwnd = tp->snd_cwnd; 848 metrics.rmx_sendpipe = 0; 849 metrics.rmx_recvpipe = 0; 850 851 tcp_hc_update(&inp->inp_inc, &metrics); 852 } 853 854 /* free the reassembly queue, if any */ 855 tcp_reass_flush(tp); 856 /* Disconnect offload device, if any. */ 857 tcp_offload_detach(tp); 858 859 tcp_free_sackholes(tp); 860 inp->inp_ppcb = NULL; 861 tp->t_inpcb = NULL; 862 uma_zfree(V_tcpcb_zone, tp); 863 } 864 865 /* 866 * Attempt to close a TCP control block, marking it as dropped, and freeing 867 * the socket if we hold the only reference. 868 */ 869 struct tcpcb * 870 tcp_close(struct tcpcb *tp) 871 { 872 struct inpcb *inp = tp->t_inpcb; 873 struct socket *so; 874 875 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 876 INP_WLOCK_ASSERT(inp); 877 878 /* Notify any offload devices of listener close */ 879 if (tp->t_state == TCPS_LISTEN) 880 tcp_offload_listen_close(tp); 881 in_pcbdrop(inp); 882 TCPSTAT_INC(tcps_closed); 883 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 884 so = inp->inp_socket; 885 soisdisconnected(so); 886 if (inp->inp_flags & INP_SOCKREF) { 887 KASSERT(so->so_state & SS_PROTOREF, 888 ("tcp_close: !SS_PROTOREF")); 889 inp->inp_flags &= ~INP_SOCKREF; 890 INP_WUNLOCK(inp); 891 ACCEPT_LOCK(); 892 SOCK_LOCK(so); 893 so->so_state &= ~SS_PROTOREF; 894 sofree(so); 895 return (NULL); 896 } 897 return (tp); 898 } 899 900 void 901 tcp_drain(void) 902 { 903 VNET_ITERATOR_DECL(vnet_iter); 904 905 if (!do_tcpdrain) 906 return; 907 908 VNET_LIST_RLOCK_NOSLEEP(); 909 VNET_FOREACH(vnet_iter) { 910 CURVNET_SET(vnet_iter); 911 struct inpcb *inpb; 912 struct tcpcb *tcpb; 913 914 /* 915 * Walk the tcpbs, if existing, and flush the reassembly queue, 916 * if there is one... 917 * XXX: The "Net/3" implementation doesn't imply that the TCP 918 * reassembly queue should be flushed, but in a situation 919 * where we're really low on mbufs, this is potentially 920 * usefull. 921 */ 922 INP_INFO_RLOCK(&V_tcbinfo); 923 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) { 924 if (inpb->inp_flags & INP_TIMEWAIT) 925 continue; 926 INP_WLOCK(inpb); 927 if ((tcpb = intotcpcb(inpb)) != NULL) { 928 tcp_reass_flush(tcpb); 929 tcp_clean_sackreport(tcpb); 930 } 931 INP_WUNLOCK(inpb); 932 } 933 INP_INFO_RUNLOCK(&V_tcbinfo); 934 CURVNET_RESTORE(); 935 } 936 VNET_LIST_RUNLOCK_NOSLEEP(); 937 } 938 939 /* 940 * Notify a tcp user of an asynchronous error; 941 * store error as soft error, but wake up user 942 * (for now, won't do anything until can select for soft error). 943 * 944 * Do not wake up user since there currently is no mechanism for 945 * reporting soft errors (yet - a kqueue filter may be added). 946 */ 947 static struct inpcb * 948 tcp_notify(struct inpcb *inp, int error) 949 { 950 struct tcpcb *tp; 951 952 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 953 INP_WLOCK_ASSERT(inp); 954 955 if ((inp->inp_flags & INP_TIMEWAIT) || 956 (inp->inp_flags & INP_DROPPED)) 957 return (inp); 958 959 tp = intotcpcb(inp); 960 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 961 962 /* 963 * Ignore some errors if we are hooked up. 964 * If connection hasn't completed, has retransmitted several times, 965 * and receives a second error, give up now. This is better 966 * than waiting a long time to establish a connection that 967 * can never complete. 968 */ 969 if (tp->t_state == TCPS_ESTABLISHED && 970 (error == EHOSTUNREACH || error == ENETUNREACH || 971 error == EHOSTDOWN)) { 972 return (inp); 973 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 974 tp->t_softerror) { 975 tp = tcp_drop(tp, error); 976 if (tp != NULL) 977 return (inp); 978 else 979 return (NULL); 980 } else { 981 tp->t_softerror = error; 982 return (inp); 983 } 984 #if 0 985 wakeup( &so->so_timeo); 986 sorwakeup(so); 987 sowwakeup(so); 988 #endif 989 } 990 991 static int 992 tcp_pcblist(SYSCTL_HANDLER_ARGS) 993 { 994 int error, i, m, n, pcb_count; 995 struct inpcb *inp, **inp_list; 996 inp_gen_t gencnt; 997 struct xinpgen xig; 998 999 /* 1000 * The process of preparing the TCB list is too time-consuming and 1001 * resource-intensive to repeat twice on every request. 1002 */ 1003 if (req->oldptr == NULL) { 1004 n = V_tcbinfo.ipi_count + syncache_pcbcount(); 1005 n += imax(n / 8, 10); 1006 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb); 1007 return (0); 1008 } 1009 1010 if (req->newptr != NULL) 1011 return (EPERM); 1012 1013 /* 1014 * OK, now we're committed to doing something. 1015 */ 1016 INP_INFO_RLOCK(&V_tcbinfo); 1017 gencnt = V_tcbinfo.ipi_gencnt; 1018 n = V_tcbinfo.ipi_count; 1019 INP_INFO_RUNLOCK(&V_tcbinfo); 1020 1021 m = syncache_pcbcount(); 1022 1023 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 1024 + (n + m) * sizeof(struct xtcpcb)); 1025 if (error != 0) 1026 return (error); 1027 1028 xig.xig_len = sizeof xig; 1029 xig.xig_count = n + m; 1030 xig.xig_gen = gencnt; 1031 xig.xig_sogen = so_gencnt; 1032 error = SYSCTL_OUT(req, &xig, sizeof xig); 1033 if (error) 1034 return (error); 1035 1036 error = syncache_pcblist(req, m, &pcb_count); 1037 if (error) 1038 return (error); 1039 1040 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 1041 if (inp_list == NULL) 1042 return (ENOMEM); 1043 1044 INP_INFO_RLOCK(&V_tcbinfo); 1045 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0; 1046 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) { 1047 INP_WLOCK(inp); 1048 if (inp->inp_gencnt <= gencnt) { 1049 /* 1050 * XXX: This use of cr_cansee(), introduced with 1051 * TCP state changes, is not quite right, but for 1052 * now, better than nothing. 1053 */ 1054 if (inp->inp_flags & INP_TIMEWAIT) { 1055 if (intotw(inp) != NULL) 1056 error = cr_cansee(req->td->td_ucred, 1057 intotw(inp)->tw_cred); 1058 else 1059 error = EINVAL; /* Skip this inp. */ 1060 } else 1061 error = cr_canseeinpcb(req->td->td_ucred, inp); 1062 if (error == 0) { 1063 in_pcbref(inp); 1064 inp_list[i++] = inp; 1065 } 1066 } 1067 INP_WUNLOCK(inp); 1068 } 1069 INP_INFO_RUNLOCK(&V_tcbinfo); 1070 n = i; 1071 1072 error = 0; 1073 for (i = 0; i < n; i++) { 1074 inp = inp_list[i]; 1075 INP_RLOCK(inp); 1076 if (inp->inp_gencnt <= gencnt) { 1077 struct xtcpcb xt; 1078 void *inp_ppcb; 1079 1080 bzero(&xt, sizeof(xt)); 1081 xt.xt_len = sizeof xt; 1082 /* XXX should avoid extra copy */ 1083 bcopy(inp, &xt.xt_inp, sizeof *inp); 1084 inp_ppcb = inp->inp_ppcb; 1085 if (inp_ppcb == NULL) 1086 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1087 else if (inp->inp_flags & INP_TIMEWAIT) { 1088 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1089 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1090 } else 1091 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1092 if (inp->inp_socket != NULL) 1093 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1094 else { 1095 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1096 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1097 } 1098 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1099 INP_RUNLOCK(inp); 1100 error = SYSCTL_OUT(req, &xt, sizeof xt); 1101 } else 1102 INP_RUNLOCK(inp); 1103 } 1104 INP_INFO_WLOCK(&V_tcbinfo); 1105 for (i = 0; i < n; i++) { 1106 inp = inp_list[i]; 1107 INP_WLOCK(inp); 1108 if (!in_pcbrele(inp)) 1109 INP_WUNLOCK(inp); 1110 } 1111 INP_INFO_WUNLOCK(&V_tcbinfo); 1112 1113 if (!error) { 1114 /* 1115 * Give the user an updated idea of our state. 1116 * If the generation differs from what we told 1117 * her before, she knows that something happened 1118 * while we were processing this request, and it 1119 * might be necessary to retry. 1120 */ 1121 INP_INFO_RLOCK(&V_tcbinfo); 1122 xig.xig_gen = V_tcbinfo.ipi_gencnt; 1123 xig.xig_sogen = so_gencnt; 1124 xig.xig_count = V_tcbinfo.ipi_count + pcb_count; 1125 INP_INFO_RUNLOCK(&V_tcbinfo); 1126 error = SYSCTL_OUT(req, &xig, sizeof xig); 1127 } 1128 free(inp_list, M_TEMP); 1129 return (error); 1130 } 1131 1132 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1133 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1134 1135 static int 1136 tcp_getcred(SYSCTL_HANDLER_ARGS) 1137 { 1138 struct xucred xuc; 1139 struct sockaddr_in addrs[2]; 1140 struct inpcb *inp; 1141 int error; 1142 1143 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1144 if (error) 1145 return (error); 1146 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1147 if (error) 1148 return (error); 1149 INP_INFO_RLOCK(&V_tcbinfo); 1150 inp = in_pcblookup_hash(&V_tcbinfo, addrs[1].sin_addr, 1151 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1152 if (inp != NULL) { 1153 INP_RLOCK(inp); 1154 INP_INFO_RUNLOCK(&V_tcbinfo); 1155 if (inp->inp_socket == NULL) 1156 error = ENOENT; 1157 if (error == 0) 1158 error = cr_canseeinpcb(req->td->td_ucred, inp); 1159 if (error == 0) 1160 cru2x(inp->inp_cred, &xuc); 1161 INP_RUNLOCK(inp); 1162 } else { 1163 INP_INFO_RUNLOCK(&V_tcbinfo); 1164 error = ENOENT; 1165 } 1166 if (error == 0) 1167 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1168 return (error); 1169 } 1170 1171 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1172 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1173 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1174 1175 #ifdef INET6 1176 static int 1177 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1178 { 1179 struct xucred xuc; 1180 struct sockaddr_in6 addrs[2]; 1181 struct inpcb *inp; 1182 int error, mapped = 0; 1183 1184 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1185 if (error) 1186 return (error); 1187 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1188 if (error) 1189 return (error); 1190 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 || 1191 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) { 1192 return (error); 1193 } 1194 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1195 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1196 mapped = 1; 1197 else 1198 return (EINVAL); 1199 } 1200 1201 INP_INFO_RLOCK(&V_tcbinfo); 1202 if (mapped == 1) 1203 inp = in_pcblookup_hash(&V_tcbinfo, 1204 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1205 addrs[1].sin6_port, 1206 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1207 addrs[0].sin6_port, 1208 0, NULL); 1209 else 1210 inp = in6_pcblookup_hash(&V_tcbinfo, 1211 &addrs[1].sin6_addr, addrs[1].sin6_port, 1212 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1213 if (inp != NULL) { 1214 INP_RLOCK(inp); 1215 INP_INFO_RUNLOCK(&V_tcbinfo); 1216 if (inp->inp_socket == NULL) 1217 error = ENOENT; 1218 if (error == 0) 1219 error = cr_canseeinpcb(req->td->td_ucred, inp); 1220 if (error == 0) 1221 cru2x(inp->inp_cred, &xuc); 1222 INP_RUNLOCK(inp); 1223 } else { 1224 INP_INFO_RUNLOCK(&V_tcbinfo); 1225 error = ENOENT; 1226 } 1227 if (error == 0) 1228 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1229 return (error); 1230 } 1231 1232 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1233 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1234 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1235 #endif 1236 1237 1238 void 1239 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1240 { 1241 struct ip *ip = vip; 1242 struct tcphdr *th; 1243 struct in_addr faddr; 1244 struct inpcb *inp; 1245 struct tcpcb *tp; 1246 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1247 struct icmp *icp; 1248 struct in_conninfo inc; 1249 tcp_seq icmp_tcp_seq; 1250 int mtu; 1251 1252 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1253 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1254 return; 1255 1256 if (cmd == PRC_MSGSIZE) 1257 notify = tcp_mtudisc; 1258 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1259 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1260 notify = tcp_drop_syn_sent; 1261 /* 1262 * Redirects don't need to be handled up here. 1263 */ 1264 else if (PRC_IS_REDIRECT(cmd)) 1265 return; 1266 /* 1267 * Source quench is depreciated. 1268 */ 1269 else if (cmd == PRC_QUENCH) 1270 return; 1271 /* 1272 * Hostdead is ugly because it goes linearly through all PCBs. 1273 * XXX: We never get this from ICMP, otherwise it makes an 1274 * excellent DoS attack on machines with many connections. 1275 */ 1276 else if (cmd == PRC_HOSTDEAD) 1277 ip = NULL; 1278 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1279 return; 1280 if (ip != NULL) { 1281 icp = (struct icmp *)((caddr_t)ip 1282 - offsetof(struct icmp, icmp_ip)); 1283 th = (struct tcphdr *)((caddr_t)ip 1284 + (ip->ip_hl << 2)); 1285 INP_INFO_WLOCK(&V_tcbinfo); 1286 inp = in_pcblookup_hash(&V_tcbinfo, faddr, th->th_dport, 1287 ip->ip_src, th->th_sport, 0, NULL); 1288 if (inp != NULL) { 1289 INP_WLOCK(inp); 1290 if (!(inp->inp_flags & INP_TIMEWAIT) && 1291 !(inp->inp_flags & INP_DROPPED) && 1292 !(inp->inp_socket == NULL)) { 1293 icmp_tcp_seq = htonl(th->th_seq); 1294 tp = intotcpcb(inp); 1295 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1296 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1297 if (cmd == PRC_MSGSIZE) { 1298 /* 1299 * MTU discovery: 1300 * If we got a needfrag set the MTU 1301 * in the route to the suggested new 1302 * value (if given) and then notify. 1303 */ 1304 bzero(&inc, sizeof(inc)); 1305 inc.inc_faddr = faddr; 1306 inc.inc_fibnum = 1307 inp->inp_inc.inc_fibnum; 1308 1309 mtu = ntohs(icp->icmp_nextmtu); 1310 /* 1311 * If no alternative MTU was 1312 * proposed, try the next smaller 1313 * one. ip->ip_len has already 1314 * been swapped in icmp_input(). 1315 */ 1316 if (!mtu) 1317 mtu = ip_next_mtu(ip->ip_len, 1318 1); 1319 if (mtu < V_tcp_minmss 1320 + sizeof(struct tcpiphdr)) 1321 mtu = V_tcp_minmss 1322 + sizeof(struct tcpiphdr); 1323 /* 1324 * Only cache the the MTU if it 1325 * is smaller than the interface 1326 * or route MTU. tcp_mtudisc() 1327 * will do right thing by itself. 1328 */ 1329 if (mtu <= tcp_maxmtu(&inc, NULL)) 1330 tcp_hc_updatemtu(&inc, mtu); 1331 } 1332 1333 inp = (*notify)(inp, inetctlerrmap[cmd]); 1334 } 1335 } 1336 if (inp != NULL) 1337 INP_WUNLOCK(inp); 1338 } else { 1339 bzero(&inc, sizeof(inc)); 1340 inc.inc_fport = th->th_dport; 1341 inc.inc_lport = th->th_sport; 1342 inc.inc_faddr = faddr; 1343 inc.inc_laddr = ip->ip_src; 1344 syncache_unreach(&inc, th); 1345 } 1346 INP_INFO_WUNLOCK(&V_tcbinfo); 1347 } else 1348 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify); 1349 } 1350 1351 #ifdef INET6 1352 void 1353 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1354 { 1355 struct tcphdr th; 1356 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1357 struct ip6_hdr *ip6; 1358 struct mbuf *m; 1359 struct ip6ctlparam *ip6cp = NULL; 1360 const struct sockaddr_in6 *sa6_src = NULL; 1361 int off; 1362 struct tcp_portonly { 1363 u_int16_t th_sport; 1364 u_int16_t th_dport; 1365 } *thp; 1366 1367 if (sa->sa_family != AF_INET6 || 1368 sa->sa_len != sizeof(struct sockaddr_in6)) 1369 return; 1370 1371 if (cmd == PRC_MSGSIZE) 1372 notify = tcp_mtudisc; 1373 else if (!PRC_IS_REDIRECT(cmd) && 1374 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1375 return; 1376 /* Source quench is depreciated. */ 1377 else if (cmd == PRC_QUENCH) 1378 return; 1379 1380 /* if the parameter is from icmp6, decode it. */ 1381 if (d != NULL) { 1382 ip6cp = (struct ip6ctlparam *)d; 1383 m = ip6cp->ip6c_m; 1384 ip6 = ip6cp->ip6c_ip6; 1385 off = ip6cp->ip6c_off; 1386 sa6_src = ip6cp->ip6c_src; 1387 } else { 1388 m = NULL; 1389 ip6 = NULL; 1390 off = 0; /* fool gcc */ 1391 sa6_src = &sa6_any; 1392 } 1393 1394 if (ip6 != NULL) { 1395 struct in_conninfo inc; 1396 /* 1397 * XXX: We assume that when IPV6 is non NULL, 1398 * M and OFF are valid. 1399 */ 1400 1401 /* check if we can safely examine src and dst ports */ 1402 if (m->m_pkthdr.len < off + sizeof(*thp)) 1403 return; 1404 1405 bzero(&th, sizeof(th)); 1406 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1407 1408 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport, 1409 (struct sockaddr *)ip6cp->ip6c_src, 1410 th.th_sport, cmd, NULL, notify); 1411 1412 bzero(&inc, sizeof(inc)); 1413 inc.inc_fport = th.th_dport; 1414 inc.inc_lport = th.th_sport; 1415 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1416 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1417 inc.inc_flags |= INC_ISIPV6; 1418 INP_INFO_WLOCK(&V_tcbinfo); 1419 syncache_unreach(&inc, &th); 1420 INP_INFO_WUNLOCK(&V_tcbinfo); 1421 } else 1422 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1423 0, cmd, NULL, notify); 1424 } 1425 #endif /* INET6 */ 1426 1427 1428 /* 1429 * Following is where TCP initial sequence number generation occurs. 1430 * 1431 * There are two places where we must use initial sequence numbers: 1432 * 1. In SYN-ACK packets. 1433 * 2. In SYN packets. 1434 * 1435 * All ISNs for SYN-ACK packets are generated by the syncache. See 1436 * tcp_syncache.c for details. 1437 * 1438 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1439 * depends on this property. In addition, these ISNs should be 1440 * unguessable so as to prevent connection hijacking. To satisfy 1441 * the requirements of this situation, the algorithm outlined in 1442 * RFC 1948 is used, with only small modifications. 1443 * 1444 * Implementation details: 1445 * 1446 * Time is based off the system timer, and is corrected so that it 1447 * increases by one megabyte per second. This allows for proper 1448 * recycling on high speed LANs while still leaving over an hour 1449 * before rollover. 1450 * 1451 * As reading the *exact* system time is too expensive to be done 1452 * whenever setting up a TCP connection, we increment the time 1453 * offset in two ways. First, a small random positive increment 1454 * is added to isn_offset for each connection that is set up. 1455 * Second, the function tcp_isn_tick fires once per clock tick 1456 * and increments isn_offset as necessary so that sequence numbers 1457 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1458 * random positive increments serve only to ensure that the same 1459 * exact sequence number is never sent out twice (as could otherwise 1460 * happen when a port is recycled in less than the system tick 1461 * interval.) 1462 * 1463 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1464 * between seeding of isn_secret. This is normally set to zero, 1465 * as reseeding should not be necessary. 1466 * 1467 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1468 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1469 * general, this means holding an exclusive (write) lock. 1470 */ 1471 1472 #define ISN_BYTES_PER_SECOND 1048576 1473 #define ISN_STATIC_INCREMENT 4096 1474 #define ISN_RANDOM_INCREMENT (4096 - 1) 1475 1476 static VNET_DEFINE(u_char, isn_secret[32]); 1477 static VNET_DEFINE(int, isn_last_reseed); 1478 static VNET_DEFINE(u_int32_t, isn_offset); 1479 static VNET_DEFINE(u_int32_t, isn_offset_old); 1480 1481 #define V_isn_secret VNET(isn_secret) 1482 #define V_isn_last_reseed VNET(isn_last_reseed) 1483 #define V_isn_offset VNET(isn_offset) 1484 #define V_isn_offset_old VNET(isn_offset_old) 1485 1486 tcp_seq 1487 tcp_new_isn(struct tcpcb *tp) 1488 { 1489 MD5_CTX isn_ctx; 1490 u_int32_t md5_buffer[4]; 1491 tcp_seq new_isn; 1492 1493 INP_WLOCK_ASSERT(tp->t_inpcb); 1494 1495 ISN_LOCK(); 1496 /* Seed if this is the first use, reseed if requested. */ 1497 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) && 1498 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz) 1499 < (u_int)ticks))) { 1500 read_random(&V_isn_secret, sizeof(V_isn_secret)); 1501 V_isn_last_reseed = ticks; 1502 } 1503 1504 /* Compute the md5 hash and return the ISN. */ 1505 MD5Init(&isn_ctx); 1506 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1507 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1508 #ifdef INET6 1509 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1510 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1511 sizeof(struct in6_addr)); 1512 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1513 sizeof(struct in6_addr)); 1514 } else 1515 #endif 1516 { 1517 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1518 sizeof(struct in_addr)); 1519 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1520 sizeof(struct in_addr)); 1521 } 1522 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret)); 1523 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1524 new_isn = (tcp_seq) md5_buffer[0]; 1525 V_isn_offset += ISN_STATIC_INCREMENT + 1526 (arc4random() & ISN_RANDOM_INCREMENT); 1527 new_isn += V_isn_offset; 1528 ISN_UNLOCK(); 1529 return (new_isn); 1530 } 1531 1532 /* 1533 * Increment the offset to the next ISN_BYTES_PER_SECOND / 100 boundary 1534 * to keep time flowing at a relatively constant rate. If the random 1535 * increments have already pushed us past the projected offset, do nothing. 1536 */ 1537 static void 1538 tcp_isn_tick(void *xtp) 1539 { 1540 VNET_ITERATOR_DECL(vnet_iter); 1541 u_int32_t projected_offset; 1542 1543 VNET_LIST_RLOCK_NOSLEEP(); 1544 ISN_LOCK(); 1545 VNET_FOREACH(vnet_iter) { 1546 CURVNET_SET(vnet_iter); /* XXX appease INVARIANTS */ 1547 projected_offset = 1548 V_isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1549 1550 if (SEQ_GT(projected_offset, V_isn_offset)) 1551 V_isn_offset = projected_offset; 1552 1553 V_isn_offset_old = V_isn_offset; 1554 CURVNET_RESTORE(); 1555 } 1556 ISN_UNLOCK(); 1557 VNET_LIST_RUNLOCK_NOSLEEP(); 1558 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1559 } 1560 1561 /* 1562 * When a specific ICMP unreachable message is received and the 1563 * connection state is SYN-SENT, drop the connection. This behavior 1564 * is controlled by the icmp_may_rst sysctl. 1565 */ 1566 struct inpcb * 1567 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1568 { 1569 struct tcpcb *tp; 1570 1571 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 1572 INP_WLOCK_ASSERT(inp); 1573 1574 if ((inp->inp_flags & INP_TIMEWAIT) || 1575 (inp->inp_flags & INP_DROPPED)) 1576 return (inp); 1577 1578 tp = intotcpcb(inp); 1579 if (tp->t_state != TCPS_SYN_SENT) 1580 return (inp); 1581 1582 tp = tcp_drop(tp, errno); 1583 if (tp != NULL) 1584 return (inp); 1585 else 1586 return (NULL); 1587 } 1588 1589 /* 1590 * When `need fragmentation' ICMP is received, update our idea of the MSS 1591 * based on the new value in the route. Also nudge TCP to send something, 1592 * since we know the packet we just sent was dropped. 1593 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1594 */ 1595 struct inpcb * 1596 tcp_mtudisc(struct inpcb *inp, int errno) 1597 { 1598 struct tcpcb *tp; 1599 struct socket *so; 1600 1601 INP_WLOCK_ASSERT(inp); 1602 if ((inp->inp_flags & INP_TIMEWAIT) || 1603 (inp->inp_flags & INP_DROPPED)) 1604 return (inp); 1605 1606 tp = intotcpcb(inp); 1607 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1608 1609 tcp_mss_update(tp, -1, NULL, NULL); 1610 1611 so = inp->inp_socket; 1612 SOCKBUF_LOCK(&so->so_snd); 1613 /* If the mss is larger than the socket buffer, decrease the mss. */ 1614 if (so->so_snd.sb_hiwat < tp->t_maxseg) 1615 tp->t_maxseg = so->so_snd.sb_hiwat; 1616 SOCKBUF_UNLOCK(&so->so_snd); 1617 1618 TCPSTAT_INC(tcps_mturesent); 1619 tp->t_rtttime = 0; 1620 tp->snd_nxt = tp->snd_una; 1621 tcp_free_sackholes(tp); 1622 tp->snd_recover = tp->snd_max; 1623 if (tp->t_flags & TF_SACK_PERMIT) 1624 EXIT_FASTRECOVERY(tp); 1625 tcp_output_send(tp); 1626 return (inp); 1627 } 1628 1629 /* 1630 * Look-up the routing entry to the peer of this inpcb. If no route 1631 * is found and it cannot be allocated, then return 0. This routine 1632 * is called by TCP routines that access the rmx structure and by 1633 * tcp_mss_update to get the peer/interface MTU. 1634 */ 1635 u_long 1636 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1637 { 1638 struct route sro; 1639 struct sockaddr_in *dst; 1640 struct ifnet *ifp; 1641 u_long maxmtu = 0; 1642 1643 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1644 1645 bzero(&sro, sizeof(sro)); 1646 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1647 dst = (struct sockaddr_in *)&sro.ro_dst; 1648 dst->sin_family = AF_INET; 1649 dst->sin_len = sizeof(*dst); 1650 dst->sin_addr = inc->inc_faddr; 1651 in_rtalloc_ign(&sro, 0, inc->inc_fibnum); 1652 } 1653 if (sro.ro_rt != NULL) { 1654 ifp = sro.ro_rt->rt_ifp; 1655 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1656 maxmtu = ifp->if_mtu; 1657 else 1658 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1659 1660 /* Report additional interface capabilities. */ 1661 if (flags != NULL) { 1662 if (ifp->if_capenable & IFCAP_TSO4 && 1663 ifp->if_hwassist & CSUM_TSO) 1664 *flags |= CSUM_TSO; 1665 } 1666 RTFREE(sro.ro_rt); 1667 } 1668 return (maxmtu); 1669 } 1670 1671 #ifdef INET6 1672 u_long 1673 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1674 { 1675 struct route_in6 sro6; 1676 struct ifnet *ifp; 1677 u_long maxmtu = 0; 1678 1679 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1680 1681 bzero(&sro6, sizeof(sro6)); 1682 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1683 sro6.ro_dst.sin6_family = AF_INET6; 1684 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1685 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1686 rtalloc_ign((struct route *)&sro6, 0); 1687 } 1688 if (sro6.ro_rt != NULL) { 1689 ifp = sro6.ro_rt->rt_ifp; 1690 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1691 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1692 else 1693 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1694 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1695 1696 /* Report additional interface capabilities. */ 1697 if (flags != NULL) { 1698 if (ifp->if_capenable & IFCAP_TSO6 && 1699 ifp->if_hwassist & CSUM_TSO) 1700 *flags |= CSUM_TSO; 1701 } 1702 RTFREE(sro6.ro_rt); 1703 } 1704 1705 return (maxmtu); 1706 } 1707 #endif /* INET6 */ 1708 1709 #ifdef IPSEC 1710 /* compute ESP/AH header size for TCP, including outer IP header. */ 1711 size_t 1712 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1713 { 1714 struct inpcb *inp; 1715 struct mbuf *m; 1716 size_t hdrsiz; 1717 struct ip *ip; 1718 #ifdef INET6 1719 struct ip6_hdr *ip6; 1720 #endif 1721 struct tcphdr *th; 1722 1723 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1724 return (0); 1725 MGETHDR(m, M_DONTWAIT, MT_DATA); 1726 if (!m) 1727 return (0); 1728 1729 #ifdef INET6 1730 if ((inp->inp_vflag & INP_IPV6) != 0) { 1731 ip6 = mtod(m, struct ip6_hdr *); 1732 th = (struct tcphdr *)(ip6 + 1); 1733 m->m_pkthdr.len = m->m_len = 1734 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1735 tcpip_fillheaders(inp, ip6, th); 1736 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1737 } else 1738 #endif /* INET6 */ 1739 { 1740 ip = mtod(m, struct ip *); 1741 th = (struct tcphdr *)(ip + 1); 1742 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1743 tcpip_fillheaders(inp, ip, th); 1744 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1745 } 1746 1747 m_free(m); 1748 return (hdrsiz); 1749 } 1750 #endif /* IPSEC */ 1751 1752 /* 1753 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1754 * 1755 * This code attempts to calculate the bandwidth-delay product as a 1756 * means of determining the optimal window size to maximize bandwidth, 1757 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1758 * routers. This code also does a fairly good job keeping RTTs in check 1759 * across slow links like modems. We implement an algorithm which is very 1760 * similar (but not meant to be) TCP/Vegas. The code operates on the 1761 * transmitter side of a TCP connection and so only effects the transmit 1762 * side of the connection. 1763 * 1764 * BACKGROUND: TCP makes no provision for the management of buffer space 1765 * at the end points or at the intermediate routers and switches. A TCP 1766 * stream, whether using NewReno or not, will eventually buffer as 1767 * many packets as it is able and the only reason this typically works is 1768 * due to the fairly small default buffers made available for a connection 1769 * (typicaly 16K or 32K). As machines use larger windows and/or window 1770 * scaling it is now fairly easy for even a single TCP connection to blow-out 1771 * all available buffer space not only on the local interface, but on 1772 * intermediate routers and switches as well. NewReno makes a misguided 1773 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1774 * then backing off, then steadily increasing the window again until another 1775 * failure occurs, ad-infinitum. This results in terrible oscillation that 1776 * is only made worse as network loads increase and the idea of intentionally 1777 * blowing out network buffers is, frankly, a terrible way to manage network 1778 * resources. 1779 * 1780 * It is far better to limit the transmit window prior to the failure 1781 * condition being achieved. There are two general ways to do this: First 1782 * you can 'scan' through different transmit window sizes and locate the 1783 * point where the RTT stops increasing, indicating that you have filled the 1784 * pipe, then scan backwards until you note that RTT stops decreasing, then 1785 * repeat ad-infinitum. This method works in principle but has severe 1786 * implementation issues due to RTT variances, timer granularity, and 1787 * instability in the algorithm which can lead to many false positives and 1788 * create oscillations as well as interact badly with other TCP streams 1789 * implementing the same algorithm. 1790 * 1791 * The second method is to limit the window to the bandwidth delay product 1792 * of the link. This is the method we implement. RTT variances and our 1793 * own manipulation of the congestion window, bwnd, can potentially 1794 * destabilize the algorithm. For this reason we have to stabilize the 1795 * elements used to calculate the window. We do this by using the minimum 1796 * observed RTT, the long term average of the observed bandwidth, and 1797 * by adding two segments worth of slop. It isn't perfect but it is able 1798 * to react to changing conditions and gives us a very stable basis on 1799 * which to extend the algorithm. 1800 */ 1801 void 1802 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1803 { 1804 u_long bw; 1805 u_long bwnd; 1806 int save_ticks; 1807 1808 INP_WLOCK_ASSERT(tp->t_inpcb); 1809 1810 /* 1811 * If inflight_enable is disabled in the middle of a tcp connection, 1812 * make sure snd_bwnd is effectively disabled. 1813 */ 1814 if (V_tcp_inflight_enable == 0 || 1815 tp->t_rttlow < V_tcp_inflight_rttthresh) { 1816 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1817 tp->snd_bandwidth = 0; 1818 return; 1819 } 1820 1821 /* 1822 * Figure out the bandwidth. Due to the tick granularity this 1823 * is a very rough number and it MUST be averaged over a fairly 1824 * long period of time. XXX we need to take into account a link 1825 * that is not using all available bandwidth, but for now our 1826 * slop will ramp us up if this case occurs and the bandwidth later 1827 * increases. 1828 * 1829 * Note: if ticks rollover 'bw' may wind up negative. We must 1830 * effectively reset t_bw_rtttime for this case. 1831 */ 1832 save_ticks = ticks; 1833 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 1834 return; 1835 1836 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 1837 (save_ticks - tp->t_bw_rtttime); 1838 tp->t_bw_rtttime = save_ticks; 1839 tp->t_bw_rtseq = ack_seq; 1840 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 1841 return; 1842 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1843 1844 tp->snd_bandwidth = bw; 1845 1846 /* 1847 * Calculate the semi-static bandwidth delay product, plus two maximal 1848 * segments. The additional slop puts us squarely in the sweet 1849 * spot and also handles the bandwidth run-up case and stabilization. 1850 * Without the slop we could be locking ourselves into a lower 1851 * bandwidth. 1852 * 1853 * Situations Handled: 1854 * (1) Prevents over-queueing of packets on LANs, especially on 1855 * high speed LANs, allowing larger TCP buffers to be 1856 * specified, and also does a good job preventing 1857 * over-queueing of packets over choke points like modems 1858 * (at least for the transmit side). 1859 * 1860 * (2) Is able to handle changing network loads (bandwidth 1861 * drops so bwnd drops, bandwidth increases so bwnd 1862 * increases). 1863 * 1864 * (3) Theoretically should stabilize in the face of multiple 1865 * connections implementing the same algorithm (this may need 1866 * a little work). 1867 * 1868 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1869 * be adjusted with a sysctl but typically only needs to be 1870 * on very slow connections. A value no smaller then 5 1871 * should be used, but only reduce this default if you have 1872 * no other choice. 1873 */ 1874 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1875 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + V_tcp_inflight_stab * tp->t_maxseg / 10; 1876 #undef USERTT 1877 1878 if (tcp_inflight_debug > 0) { 1879 static int ltime; 1880 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1881 ltime = ticks; 1882 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1883 tp, 1884 bw, 1885 tp->t_rttbest, 1886 tp->t_srtt, 1887 bwnd 1888 ); 1889 } 1890 } 1891 if ((long)bwnd < V_tcp_inflight_min) 1892 bwnd = V_tcp_inflight_min; 1893 if (bwnd > V_tcp_inflight_max) 1894 bwnd = V_tcp_inflight_max; 1895 if ((long)bwnd < tp->t_maxseg * 2) 1896 bwnd = tp->t_maxseg * 2; 1897 tp->snd_bwnd = bwnd; 1898 } 1899 1900 #ifdef TCP_SIGNATURE 1901 /* 1902 * Callback function invoked by m_apply() to digest TCP segment data 1903 * contained within an mbuf chain. 1904 */ 1905 static int 1906 tcp_signature_apply(void *fstate, void *data, u_int len) 1907 { 1908 1909 MD5Update(fstate, (u_char *)data, len); 1910 return (0); 1911 } 1912 1913 /* 1914 * Compute TCP-MD5 hash of a TCP segment. (RFC2385) 1915 * 1916 * Parameters: 1917 * m pointer to head of mbuf chain 1918 * _unused 1919 * len length of TCP segment data, excluding options 1920 * optlen length of TCP segment options 1921 * buf pointer to storage for computed MD5 digest 1922 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 1923 * 1924 * We do this over ip, tcphdr, segment data, and the key in the SADB. 1925 * When called from tcp_input(), we can be sure that th_sum has been 1926 * zeroed out and verified already. 1927 * 1928 * Return 0 if successful, otherwise return -1. 1929 * 1930 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 1931 * search with the destination IP address, and a 'magic SPI' to be 1932 * determined by the application. This is hardcoded elsewhere to 1179 1933 * right now. Another branch of this code exists which uses the SPD to 1934 * specify per-application flows but it is unstable. 1935 */ 1936 int 1937 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen, 1938 u_char *buf, u_int direction) 1939 { 1940 union sockaddr_union dst; 1941 struct ippseudo ippseudo; 1942 MD5_CTX ctx; 1943 int doff; 1944 struct ip *ip; 1945 struct ipovly *ipovly; 1946 struct secasvar *sav; 1947 struct tcphdr *th; 1948 #ifdef INET6 1949 struct ip6_hdr *ip6; 1950 struct in6_addr in6; 1951 char ip6buf[INET6_ADDRSTRLEN]; 1952 uint32_t plen; 1953 uint16_t nhdr; 1954 #endif 1955 u_short savecsum; 1956 1957 KASSERT(m != NULL, ("NULL mbuf chain")); 1958 KASSERT(buf != NULL, ("NULL signature pointer")); 1959 1960 /* Extract the destination from the IP header in the mbuf. */ 1961 bzero(&dst, sizeof(union sockaddr_union)); 1962 ip = mtod(m, struct ip *); 1963 #ifdef INET6 1964 ip6 = NULL; /* Make the compiler happy. */ 1965 #endif 1966 switch (ip->ip_v) { 1967 case IPVERSION: 1968 dst.sa.sa_len = sizeof(struct sockaddr_in); 1969 dst.sa.sa_family = AF_INET; 1970 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 1971 ip->ip_src : ip->ip_dst; 1972 break; 1973 #ifdef INET6 1974 case (IPV6_VERSION >> 4): 1975 ip6 = mtod(m, struct ip6_hdr *); 1976 dst.sa.sa_len = sizeof(struct sockaddr_in6); 1977 dst.sa.sa_family = AF_INET6; 1978 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ? 1979 ip6->ip6_src : ip6->ip6_dst; 1980 break; 1981 #endif 1982 default: 1983 return (EINVAL); 1984 /* NOTREACHED */ 1985 break; 1986 } 1987 1988 /* Look up an SADB entry which matches the address of the peer. */ 1989 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 1990 if (sav == NULL) { 1991 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__, 1992 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) : 1993 #ifdef INET6 1994 (ip->ip_v == (IPV6_VERSION >> 4)) ? 1995 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) : 1996 #endif 1997 "(unsupported)")); 1998 return (EINVAL); 1999 } 2000 2001 MD5Init(&ctx); 2002 /* 2003 * Step 1: Update MD5 hash with IP(v6) pseudo-header. 2004 * 2005 * XXX The ippseudo header MUST be digested in network byte order, 2006 * or else we'll fail the regression test. Assume all fields we've 2007 * been doing arithmetic on have been in host byte order. 2008 * XXX One cannot depend on ipovly->ih_len here. When called from 2009 * tcp_output(), the underlying ip_len member has not yet been set. 2010 */ 2011 switch (ip->ip_v) { 2012 case IPVERSION: 2013 ipovly = (struct ipovly *)ip; 2014 ippseudo.ippseudo_src = ipovly->ih_src; 2015 ippseudo.ippseudo_dst = ipovly->ih_dst; 2016 ippseudo.ippseudo_pad = 0; 2017 ippseudo.ippseudo_p = IPPROTO_TCP; 2018 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + 2019 optlen); 2020 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2021 2022 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip)); 2023 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen; 2024 break; 2025 #ifdef INET6 2026 /* 2027 * RFC 2385, 2.0 Proposal 2028 * For IPv6, the pseudo-header is as described in RFC 2460, namely the 2029 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero- 2030 * extended next header value (to form 32 bits), and 32-bit segment 2031 * length. 2032 * Note: Upper-Layer Packet Length comes before Next Header. 2033 */ 2034 case (IPV6_VERSION >> 4): 2035 in6 = ip6->ip6_src; 2036 in6_clearscope(&in6); 2037 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2038 in6 = ip6->ip6_dst; 2039 in6_clearscope(&in6); 2040 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2041 plen = htonl(len + sizeof(struct tcphdr) + optlen); 2042 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t)); 2043 nhdr = 0; 2044 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2045 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2046 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2047 nhdr = IPPROTO_TCP; 2048 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2049 2050 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr)); 2051 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen; 2052 break; 2053 #endif 2054 default: 2055 return (EINVAL); 2056 /* NOTREACHED */ 2057 break; 2058 } 2059 2060 2061 /* 2062 * Step 2: Update MD5 hash with TCP header, excluding options. 2063 * The TCP checksum must be set to zero. 2064 */ 2065 savecsum = th->th_sum; 2066 th->th_sum = 0; 2067 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2068 th->th_sum = savecsum; 2069 2070 /* 2071 * Step 3: Update MD5 hash with TCP segment data. 2072 * Use m_apply() to avoid an early m_pullup(). 2073 */ 2074 if (len > 0) 2075 m_apply(m, doff, len, tcp_signature_apply, &ctx); 2076 2077 /* 2078 * Step 4: Update MD5 hash with shared secret. 2079 */ 2080 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 2081 MD5Final(buf, &ctx); 2082 2083 key_sa_recordxfer(sav, m); 2084 KEY_FREESAV(&sav); 2085 return (0); 2086 } 2087 #endif /* TCP_SIGNATURE */ 2088 2089 static int 2090 sysctl_drop(SYSCTL_HANDLER_ARGS) 2091 { 2092 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 2093 struct sockaddr_storage addrs[2]; 2094 struct inpcb *inp; 2095 struct tcpcb *tp; 2096 struct tcptw *tw; 2097 struct sockaddr_in *fin, *lin; 2098 #ifdef INET6 2099 struct sockaddr_in6 *fin6, *lin6; 2100 #endif 2101 int error; 2102 2103 inp = NULL; 2104 fin = lin = NULL; 2105 #ifdef INET6 2106 fin6 = lin6 = NULL; 2107 #endif 2108 error = 0; 2109 2110 if (req->oldptr != NULL || req->oldlen != 0) 2111 return (EINVAL); 2112 if (req->newptr == NULL) 2113 return (EPERM); 2114 if (req->newlen < sizeof(addrs)) 2115 return (ENOMEM); 2116 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2117 if (error) 2118 return (error); 2119 2120 switch (addrs[0].ss_family) { 2121 #ifdef INET6 2122 case AF_INET6: 2123 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2124 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2125 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2126 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2127 return (EINVAL); 2128 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2129 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2130 return (EINVAL); 2131 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2132 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2133 fin = (struct sockaddr_in *)&addrs[0]; 2134 lin = (struct sockaddr_in *)&addrs[1]; 2135 break; 2136 } 2137 error = sa6_embedscope(fin6, V_ip6_use_defzone); 2138 if (error) 2139 return (error); 2140 error = sa6_embedscope(lin6, V_ip6_use_defzone); 2141 if (error) 2142 return (error); 2143 break; 2144 #endif 2145 case AF_INET: 2146 fin = (struct sockaddr_in *)&addrs[0]; 2147 lin = (struct sockaddr_in *)&addrs[1]; 2148 if (fin->sin_len != sizeof(struct sockaddr_in) || 2149 lin->sin_len != sizeof(struct sockaddr_in)) 2150 return (EINVAL); 2151 break; 2152 default: 2153 return (EINVAL); 2154 } 2155 INP_INFO_WLOCK(&V_tcbinfo); 2156 switch (addrs[0].ss_family) { 2157 #ifdef INET6 2158 case AF_INET6: 2159 inp = in6_pcblookup_hash(&V_tcbinfo, &fin6->sin6_addr, 2160 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port, 0, 2161 NULL); 2162 break; 2163 #endif 2164 case AF_INET: 2165 inp = in_pcblookup_hash(&V_tcbinfo, fin->sin_addr, 2166 fin->sin_port, lin->sin_addr, lin->sin_port, 0, NULL); 2167 break; 2168 } 2169 if (inp != NULL) { 2170 INP_WLOCK(inp); 2171 if (inp->inp_flags & INP_TIMEWAIT) { 2172 /* 2173 * XXXRW: There currently exists a state where an 2174 * inpcb is present, but its timewait state has been 2175 * discarded. For now, don't allow dropping of this 2176 * type of inpcb. 2177 */ 2178 tw = intotw(inp); 2179 if (tw != NULL) 2180 tcp_twclose(tw, 0); 2181 else 2182 INP_WUNLOCK(inp); 2183 } else if (!(inp->inp_flags & INP_DROPPED) && 2184 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2185 tp = intotcpcb(inp); 2186 tp = tcp_drop(tp, ECONNABORTED); 2187 if (tp != NULL) 2188 INP_WUNLOCK(inp); 2189 } else 2190 INP_WUNLOCK(inp); 2191 } else 2192 error = ESRCH; 2193 INP_INFO_WUNLOCK(&V_tcbinfo); 2194 return (error); 2195 } 2196 2197 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2198 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2199 0, sysctl_drop, "", "Drop TCP connection"); 2200 2201 /* 2202 * Generate a standardized TCP log line for use throughout the 2203 * tcp subsystem. Memory allocation is done with M_NOWAIT to 2204 * allow use in the interrupt context. 2205 * 2206 * NB: The caller MUST free(s, M_TCPLOG) the returned string. 2207 * NB: The function may return NULL if memory allocation failed. 2208 * 2209 * Due to header inclusion and ordering limitations the struct ip 2210 * and ip6_hdr pointers have to be passed as void pointers. 2211 */ 2212 char * 2213 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2214 const void *ip6hdr) 2215 { 2216 2217 /* Is logging enabled? */ 2218 if (tcp_log_in_vain == 0) 2219 return (NULL); 2220 2221 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr)); 2222 } 2223 2224 char * 2225 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2226 const void *ip6hdr) 2227 { 2228 2229 /* Is logging enabled? */ 2230 if (tcp_log_debug == 0) 2231 return (NULL); 2232 2233 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr)); 2234 } 2235 2236 static char * 2237 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2238 const void *ip6hdr) 2239 { 2240 char *s, *sp; 2241 size_t size; 2242 struct ip *ip; 2243 #ifdef INET6 2244 const struct ip6_hdr *ip6; 2245 2246 ip6 = (const struct ip6_hdr *)ip6hdr; 2247 #endif /* INET6 */ 2248 ip = (struct ip *)ip4hdr; 2249 2250 /* 2251 * The log line looks like this: 2252 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>" 2253 */ 2254 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") + 2255 sizeof(PRINT_TH_FLAGS) + 1 + 2256 #ifdef INET6 2257 2 * INET6_ADDRSTRLEN; 2258 #else 2259 2 * INET_ADDRSTRLEN; 2260 #endif /* INET6 */ 2261 2262 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT); 2263 if (s == NULL) 2264 return (NULL); 2265 2266 strcat(s, "TCP: ["); 2267 sp = s + strlen(s); 2268 2269 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) { 2270 inet_ntoa_r(inc->inc_faddr, sp); 2271 sp = s + strlen(s); 2272 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2273 sp = s + strlen(s); 2274 inet_ntoa_r(inc->inc_laddr, sp); 2275 sp = s + strlen(s); 2276 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2277 #ifdef INET6 2278 } else if (inc) { 2279 ip6_sprintf(sp, &inc->inc6_faddr); 2280 sp = s + strlen(s); 2281 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2282 sp = s + strlen(s); 2283 ip6_sprintf(sp, &inc->inc6_laddr); 2284 sp = s + strlen(s); 2285 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2286 } else if (ip6 && th) { 2287 ip6_sprintf(sp, &ip6->ip6_src); 2288 sp = s + strlen(s); 2289 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2290 sp = s + strlen(s); 2291 ip6_sprintf(sp, &ip6->ip6_dst); 2292 sp = s + strlen(s); 2293 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2294 #endif /* INET6 */ 2295 } else if (ip && th) { 2296 inet_ntoa_r(ip->ip_src, sp); 2297 sp = s + strlen(s); 2298 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2299 sp = s + strlen(s); 2300 inet_ntoa_r(ip->ip_dst, sp); 2301 sp = s + strlen(s); 2302 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2303 } else { 2304 free(s, M_TCPLOG); 2305 return (NULL); 2306 } 2307 sp = s + strlen(s); 2308 if (th) 2309 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS); 2310 if (*(s + size - 1) != '\0') 2311 panic("%s: string too long", __func__); 2312 return (s); 2313 }
Cache object: d10544cbde141e8374e3594eadeb92bc
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