1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_compat.h" 36 #include "opt_inet.h" 37 #include "opt_inet6.h" 38 #include "opt_ipsec.h" 39 #include "opt_tcpdebug.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/callout.h> 44 #include <sys/kernel.h> 45 #include <sys/sysctl.h> 46 #include <sys/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) = 1; 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 #ifdef TCP_SORECEIVE_STREAM 261 static int tcp_soreceive_stream = 0; 262 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN, 263 &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets"); 264 #endif 265 266 VNET_DEFINE(uma_zone_t, sack_hole_zone); 267 #define V_sack_hole_zone VNET(sack_hole_zone) 268 269 static struct inpcb *tcp_notify(struct inpcb *, int); 270 static void tcp_isn_tick(void *); 271 272 /* 273 * Target size of TCP PCB hash tables. Must be a power of two. 274 * 275 * Note that this can be overridden by the kernel environment 276 * variable net.inet.tcp.tcbhashsize 277 */ 278 #ifndef TCBHASHSIZE 279 #define TCBHASHSIZE 512 280 #endif 281 282 /* 283 * XXX 284 * Callouts should be moved into struct tcp directly. They are currently 285 * separate because the tcpcb structure is exported to userland for sysctl 286 * parsing purposes, which do not know about callouts. 287 */ 288 struct tcpcb_mem { 289 struct tcpcb tcb; 290 struct tcp_timer tt; 291 }; 292 293 static VNET_DEFINE(uma_zone_t, tcpcb_zone); 294 #define V_tcpcb_zone VNET(tcpcb_zone) 295 296 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers"); 297 struct callout isn_callout; 298 static struct mtx isn_mtx; 299 300 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 301 #define ISN_LOCK() mtx_lock(&isn_mtx) 302 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 303 304 /* 305 * TCP initialization. 306 */ 307 static void 308 tcp_zone_change(void *tag) 309 { 310 311 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 312 uma_zone_set_max(V_tcpcb_zone, maxsockets); 313 tcp_tw_zone_change(); 314 } 315 316 static int 317 tcp_inpcb_init(void *mem, int size, int flags) 318 { 319 struct inpcb *inp = mem; 320 321 INP_LOCK_INIT(inp, "inp", "tcpinp"); 322 return (0); 323 } 324 325 void 326 tcp_init(void) 327 { 328 int hashsize; 329 330 hashsize = TCBHASHSIZE; 331 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 332 if (!powerof2(hashsize)) { 333 printf("WARNING: TCB hash size not a power of 2\n"); 334 hashsize = 512; /* safe default */ 335 } 336 in_pcbinfo_init(&V_tcbinfo, "tcp", &V_tcb, hashsize, hashsize, 337 "tcp_inpcb", tcp_inpcb_init, NULL, UMA_ZONE_NOFREE); 338 339 V_tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 340 341 /* 342 * These have to be type stable for the benefit of the timers. 343 */ 344 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 345 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 346 uma_zone_set_max(V_tcpcb_zone, maxsockets); 347 348 tcp_tw_init(); 349 syncache_init(); 350 tcp_hc_init(); 351 tcp_reass_init(); 352 353 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack); 354 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 355 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 356 357 /* Skip initialization of globals for non-default instances. */ 358 if (!IS_DEFAULT_VNET(curvnet)) 359 return; 360 361 /* XXX virtualize those bellow? */ 362 tcp_delacktime = TCPTV_DELACK; 363 tcp_keepinit = TCPTV_KEEP_INIT; 364 tcp_keepidle = TCPTV_KEEP_IDLE; 365 tcp_keepintvl = TCPTV_KEEPINTVL; 366 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 367 tcp_msl = TCPTV_MSL; 368 tcp_rexmit_min = TCPTV_MIN; 369 if (tcp_rexmit_min < 1) 370 tcp_rexmit_min = 1; 371 tcp_rexmit_slop = TCPTV_CPU_VAR; 372 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 373 tcp_tcbhashsize = hashsize; 374 375 #ifdef TCP_SORECEIVE_STREAM 376 TUNABLE_INT_FETCH("net.inet.tcp.soreceive_stream", &tcp_soreceive_stream); 377 if (tcp_soreceive_stream) { 378 tcp_usrreqs.pru_soreceive = soreceive_stream; 379 tcp6_usrreqs.pru_soreceive = soreceive_stream; 380 } 381 #endif 382 383 #ifdef INET6 384 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 385 #else /* INET6 */ 386 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 387 #endif /* INET6 */ 388 if (max_protohdr < TCP_MINPROTOHDR) 389 max_protohdr = TCP_MINPROTOHDR; 390 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 391 panic("tcp_init"); 392 #undef TCP_MINPROTOHDR 393 394 ISN_LOCK_INIT(); 395 callout_init(&isn_callout, CALLOUT_MPSAFE); 396 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 397 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 398 SHUTDOWN_PRI_DEFAULT); 399 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 400 EVENTHANDLER_PRI_ANY); 401 } 402 403 #ifdef VIMAGE 404 void 405 tcp_destroy(void) 406 { 407 408 tcp_reass_destroy(); 409 tcp_hc_destroy(); 410 syncache_destroy(); 411 tcp_tw_destroy(); 412 in_pcbinfo_destroy(&V_tcbinfo); 413 uma_zdestroy(V_sack_hole_zone); 414 uma_zdestroy(V_tcpcb_zone); 415 } 416 #endif 417 418 void 419 tcp_fini(void *xtp) 420 { 421 422 callout_stop(&isn_callout); 423 } 424 425 /* 426 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 427 * tcp_template used to store this data in mbufs, but we now recopy it out 428 * of the tcpcb each time to conserve mbufs. 429 */ 430 void 431 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 432 { 433 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 434 435 INP_WLOCK_ASSERT(inp); 436 437 #ifdef INET6 438 if ((inp->inp_vflag & INP_IPV6) != 0) { 439 struct ip6_hdr *ip6; 440 441 ip6 = (struct ip6_hdr *)ip_ptr; 442 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 443 (inp->inp_flow & IPV6_FLOWINFO_MASK); 444 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 445 (IPV6_VERSION & IPV6_VERSION_MASK); 446 ip6->ip6_nxt = IPPROTO_TCP; 447 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 448 ip6->ip6_src = inp->in6p_laddr; 449 ip6->ip6_dst = inp->in6p_faddr; 450 } else 451 #endif 452 { 453 struct ip *ip; 454 455 ip = (struct ip *)ip_ptr; 456 ip->ip_v = IPVERSION; 457 ip->ip_hl = 5; 458 ip->ip_tos = inp->inp_ip_tos; 459 ip->ip_len = 0; 460 ip->ip_id = 0; 461 ip->ip_off = 0; 462 ip->ip_ttl = inp->inp_ip_ttl; 463 ip->ip_sum = 0; 464 ip->ip_p = IPPROTO_TCP; 465 ip->ip_src = inp->inp_laddr; 466 ip->ip_dst = inp->inp_faddr; 467 } 468 th->th_sport = inp->inp_lport; 469 th->th_dport = inp->inp_fport; 470 th->th_seq = 0; 471 th->th_ack = 0; 472 th->th_x2 = 0; 473 th->th_off = 5; 474 th->th_flags = 0; 475 th->th_win = 0; 476 th->th_urp = 0; 477 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 478 } 479 480 /* 481 * Create template to be used to send tcp packets on a connection. 482 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 483 * use for this function is in keepalives, which use tcp_respond. 484 */ 485 struct tcptemp * 486 tcpip_maketemplate(struct inpcb *inp) 487 { 488 struct tcptemp *t; 489 490 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT); 491 if (t == NULL) 492 return (NULL); 493 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t); 494 return (t); 495 } 496 497 /* 498 * Send a single message to the TCP at address specified by 499 * the given TCP/IP header. If m == NULL, then we make a copy 500 * of the tcpiphdr at ti and send directly to the addressed host. 501 * This is used to force keep alive messages out using the TCP 502 * template for a connection. If flags are given then we send 503 * a message back to the TCP which originated the * segment ti, 504 * and discard the mbuf containing it and any other attached mbufs. 505 * 506 * In any case the ack and sequence number of the transmitted 507 * segment are as specified by the parameters. 508 * 509 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 510 */ 511 void 512 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 513 tcp_seq ack, tcp_seq seq, int flags) 514 { 515 int tlen; 516 int win = 0; 517 struct ip *ip; 518 struct tcphdr *nth; 519 #ifdef INET6 520 struct ip6_hdr *ip6; 521 int isipv6; 522 #endif /* INET6 */ 523 int ipflags = 0; 524 struct inpcb *inp; 525 526 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 527 528 #ifdef INET6 529 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 530 ip6 = ipgen; 531 #endif /* INET6 */ 532 ip = ipgen; 533 534 if (tp != NULL) { 535 inp = tp->t_inpcb; 536 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 537 INP_WLOCK_ASSERT(inp); 538 } else 539 inp = NULL; 540 541 if (tp != NULL) { 542 if (!(flags & TH_RST)) { 543 win = sbspace(&inp->inp_socket->so_rcv); 544 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 545 win = (long)TCP_MAXWIN << tp->rcv_scale; 546 } 547 } 548 if (m == NULL) { 549 m = m_gethdr(M_DONTWAIT, MT_DATA); 550 if (m == NULL) 551 return; 552 tlen = 0; 553 m->m_data += max_linkhdr; 554 #ifdef INET6 555 if (isipv6) { 556 bcopy((caddr_t)ip6, mtod(m, caddr_t), 557 sizeof(struct ip6_hdr)); 558 ip6 = mtod(m, struct ip6_hdr *); 559 nth = (struct tcphdr *)(ip6 + 1); 560 } else 561 #endif /* INET6 */ 562 { 563 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 564 ip = mtod(m, struct ip *); 565 nth = (struct tcphdr *)(ip + 1); 566 } 567 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 568 flags = TH_ACK; 569 } else { 570 /* 571 * reuse the mbuf. 572 * XXX MRT We inherrit the FIB, which is lucky. 573 */ 574 m_freem(m->m_next); 575 m->m_next = NULL; 576 m->m_data = (caddr_t)ipgen; 577 /* m_len is set later */ 578 tlen = 0; 579 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 580 #ifdef INET6 581 if (isipv6) { 582 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 583 nth = (struct tcphdr *)(ip6 + 1); 584 } else 585 #endif /* INET6 */ 586 { 587 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t); 588 nth = (struct tcphdr *)(ip + 1); 589 } 590 if (th != nth) { 591 /* 592 * this is usually a case when an extension header 593 * exists between the IPv6 header and the 594 * TCP header. 595 */ 596 nth->th_sport = th->th_sport; 597 nth->th_dport = th->th_dport; 598 } 599 xchg(nth->th_dport, nth->th_sport, uint16_t); 600 #undef xchg 601 } 602 #ifdef INET6 603 if (isipv6) { 604 ip6->ip6_flow = 0; 605 ip6->ip6_vfc = IPV6_VERSION; 606 ip6->ip6_nxt = IPPROTO_TCP; 607 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 608 tlen)); 609 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 610 } else 611 #endif 612 { 613 tlen += sizeof (struct tcpiphdr); 614 ip->ip_len = tlen; 615 ip->ip_ttl = V_ip_defttl; 616 if (V_path_mtu_discovery) 617 ip->ip_off |= IP_DF; 618 } 619 m->m_len = tlen; 620 m->m_pkthdr.len = tlen; 621 m->m_pkthdr.rcvif = NULL; 622 #ifdef MAC 623 if (inp != NULL) { 624 /* 625 * Packet is associated with a socket, so allow the 626 * label of the response to reflect the socket label. 627 */ 628 INP_WLOCK_ASSERT(inp); 629 mac_inpcb_create_mbuf(inp, m); 630 } else { 631 /* 632 * Packet is not associated with a socket, so possibly 633 * update the label in place. 634 */ 635 mac_netinet_tcp_reply(m); 636 } 637 #endif 638 nth->th_seq = htonl(seq); 639 nth->th_ack = htonl(ack); 640 nth->th_x2 = 0; 641 nth->th_off = sizeof (struct tcphdr) >> 2; 642 nth->th_flags = flags; 643 if (tp != NULL) 644 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 645 else 646 nth->th_win = htons((u_short)win); 647 nth->th_urp = 0; 648 #ifdef INET6 649 if (isipv6) { 650 nth->th_sum = 0; 651 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 652 sizeof(struct ip6_hdr), 653 tlen - sizeof(struct ip6_hdr)); 654 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 655 NULL, NULL); 656 } else 657 #endif /* INET6 */ 658 { 659 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 660 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 661 m->m_pkthdr.csum_flags = CSUM_TCP; 662 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 663 } 664 #ifdef TCPDEBUG 665 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 666 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 667 #endif 668 #ifdef INET6 669 if (isipv6) 670 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 671 else 672 #endif /* INET6 */ 673 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 674 } 675 676 /* 677 * Create a new TCP control block, making an 678 * empty reassembly queue and hooking it to the argument 679 * protocol control block. The `inp' parameter must have 680 * come from the zone allocator set up in tcp_init(). 681 */ 682 struct tcpcb * 683 tcp_newtcpcb(struct inpcb *inp) 684 { 685 struct tcpcb_mem *tm; 686 struct tcpcb *tp; 687 #ifdef INET6 688 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 689 #endif /* INET6 */ 690 691 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO); 692 if (tm == NULL) 693 return (NULL); 694 tp = &tm->tcb; 695 #ifdef VIMAGE 696 tp->t_vnet = inp->inp_vnet; 697 #endif 698 tp->t_timers = &tm->tt; 699 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 700 tp->t_maxseg = tp->t_maxopd = 701 #ifdef INET6 702 isipv6 ? V_tcp_v6mssdflt : 703 #endif /* INET6 */ 704 V_tcp_mssdflt; 705 706 /* Set up our timeouts. */ 707 callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE); 708 callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE); 709 callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE); 710 callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE); 711 callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE); 712 713 if (V_tcp_do_rfc1323) 714 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 715 if (V_tcp_do_sack) 716 tp->t_flags |= TF_SACK_PERMIT; 717 TAILQ_INIT(&tp->snd_holes); 718 tp->t_inpcb = inp; /* XXX */ 719 /* 720 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 721 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 722 * reasonable initial retransmit time. 723 */ 724 tp->t_srtt = TCPTV_SRTTBASE; 725 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 726 tp->t_rttmin = tcp_rexmit_min; 727 tp->t_rxtcur = TCPTV_RTOBASE; 728 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 729 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 730 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 731 tp->t_rcvtime = ticks; 732 tp->t_bw_rtttime = ticks; 733 /* 734 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 735 * because the socket may be bound to an IPv6 wildcard address, 736 * which may match an IPv4-mapped IPv6 address. 737 */ 738 inp->inp_ip_ttl = V_ip_defttl; 739 inp->inp_ppcb = tp; 740 return (tp); /* XXX */ 741 } 742 743 /* 744 * Drop a TCP connection, reporting 745 * the specified error. If connection is synchronized, 746 * then send a RST to peer. 747 */ 748 struct tcpcb * 749 tcp_drop(struct tcpcb *tp, int errno) 750 { 751 struct socket *so = tp->t_inpcb->inp_socket; 752 753 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 754 INP_WLOCK_ASSERT(tp->t_inpcb); 755 756 if (TCPS_HAVERCVDSYN(tp->t_state)) { 757 tp->t_state = TCPS_CLOSED; 758 (void) tcp_output_reset(tp); 759 TCPSTAT_INC(tcps_drops); 760 } else 761 TCPSTAT_INC(tcps_conndrops); 762 if (errno == ETIMEDOUT && tp->t_softerror) 763 errno = tp->t_softerror; 764 so->so_error = errno; 765 return (tcp_close(tp)); 766 } 767 768 void 769 tcp_discardcb(struct tcpcb *tp) 770 { 771 struct tseg_qent *q; 772 struct inpcb *inp = tp->t_inpcb; 773 struct socket *so = inp->inp_socket; 774 #ifdef INET6 775 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 776 #endif /* INET6 */ 777 778 INP_WLOCK_ASSERT(inp); 779 780 /* 781 * Make sure that all of our timers are stopped before we delete the 782 * PCB. 783 * 784 * XXXRW: Really, we would like to use callout_drain() here in order 785 * to avoid races experienced in tcp_timer.c where a timer is already 786 * executing at this point. However, we can't, both because we're 787 * running in a context where we can't sleep, and also because we 788 * hold locks required by the timers. What we instead need to do is 789 * test to see if callout_drain() is required, and if so, defer some 790 * portion of the remainder of tcp_discardcb() to an asynchronous 791 * context that can callout_drain() and then continue. Some care 792 * will be required to ensure that no further processing takes place 793 * on the tcpcb, even though it hasn't been freed (a flag?). 794 */ 795 callout_stop(&tp->t_timers->tt_rexmt); 796 callout_stop(&tp->t_timers->tt_persist); 797 callout_stop(&tp->t_timers->tt_keep); 798 callout_stop(&tp->t_timers->tt_2msl); 799 callout_stop(&tp->t_timers->tt_delack); 800 801 /* 802 * If we got enough samples through the srtt filter, 803 * save the rtt and rttvar in the routing entry. 804 * 'Enough' is arbitrarily defined as 4 rtt samples. 805 * 4 samples is enough for the srtt filter to converge 806 * to within enough % of the correct value; fewer samples 807 * and we could save a bogus rtt. The danger is not high 808 * as tcp quickly recovers from everything. 809 * XXX: Works very well but needs some more statistics! 810 */ 811 if (tp->t_rttupdated >= 4) { 812 struct hc_metrics_lite metrics; 813 u_long ssthresh; 814 815 bzero(&metrics, sizeof(metrics)); 816 /* 817 * Update the ssthresh always when the conditions below 818 * are satisfied. This gives us better new start value 819 * for the congestion avoidance for new connections. 820 * ssthresh is only set if packet loss occured on a session. 821 * 822 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 823 * being torn down. Ideally this code would not use 'so'. 824 */ 825 ssthresh = tp->snd_ssthresh; 826 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 827 /* 828 * convert the limit from user data bytes to 829 * packets then to packet data bytes. 830 */ 831 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 832 if (ssthresh < 2) 833 ssthresh = 2; 834 ssthresh *= (u_long)(tp->t_maxseg + 835 #ifdef INET6 836 (isipv6 ? sizeof (struct ip6_hdr) + 837 sizeof (struct tcphdr) : 838 #endif 839 sizeof (struct tcpiphdr) 840 #ifdef INET6 841 ) 842 #endif 843 ); 844 } else 845 ssthresh = 0; 846 metrics.rmx_ssthresh = ssthresh; 847 848 metrics.rmx_rtt = tp->t_srtt; 849 metrics.rmx_rttvar = tp->t_rttvar; 850 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 851 metrics.rmx_bandwidth = tp->snd_bandwidth; 852 metrics.rmx_cwnd = tp->snd_cwnd; 853 metrics.rmx_sendpipe = 0; 854 metrics.rmx_recvpipe = 0; 855 856 tcp_hc_update(&inp->inp_inc, &metrics); 857 } 858 859 /* free the reassembly queue, if any */ 860 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) { 861 LIST_REMOVE(q, tqe_q); 862 m_freem(q->tqe_m); 863 uma_zfree(V_tcp_reass_zone, q); 864 tp->t_segqlen--; 865 V_tcp_reass_qsize--; 866 } 867 /* Disconnect offload device, if any. */ 868 tcp_offload_detach(tp); 869 870 tcp_free_sackholes(tp); 871 inp->inp_ppcb = NULL; 872 tp->t_inpcb = NULL; 873 uma_zfree(V_tcpcb_zone, tp); 874 } 875 876 /* 877 * Attempt to close a TCP control block, marking it as dropped, and freeing 878 * the socket if we hold the only reference. 879 */ 880 struct tcpcb * 881 tcp_close(struct tcpcb *tp) 882 { 883 struct inpcb *inp = tp->t_inpcb; 884 struct socket *so; 885 886 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 887 INP_WLOCK_ASSERT(inp); 888 889 /* Notify any offload devices of listener close */ 890 if (tp->t_state == TCPS_LISTEN) 891 tcp_offload_listen_close(tp); 892 in_pcbdrop(inp); 893 TCPSTAT_INC(tcps_closed); 894 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 895 so = inp->inp_socket; 896 soisdisconnected(so); 897 if (inp->inp_flags & INP_SOCKREF) { 898 KASSERT(so->so_state & SS_PROTOREF, 899 ("tcp_close: !SS_PROTOREF")); 900 inp->inp_flags &= ~INP_SOCKREF; 901 INP_WUNLOCK(inp); 902 ACCEPT_LOCK(); 903 SOCK_LOCK(so); 904 so->so_state &= ~SS_PROTOREF; 905 sofree(so); 906 return (NULL); 907 } 908 return (tp); 909 } 910 911 void 912 tcp_drain(void) 913 { 914 VNET_ITERATOR_DECL(vnet_iter); 915 916 if (!do_tcpdrain) 917 return; 918 919 VNET_LIST_RLOCK_NOSLEEP(); 920 VNET_FOREACH(vnet_iter) { 921 CURVNET_SET(vnet_iter); 922 struct inpcb *inpb; 923 struct tcpcb *tcpb; 924 struct tseg_qent *te; 925 926 /* 927 * Walk the tcpbs, if existing, and flush the reassembly queue, 928 * if there is one... 929 * XXX: The "Net/3" implementation doesn't imply that the TCP 930 * reassembly queue should be flushed, but in a situation 931 * where we're really low on mbufs, this is potentially 932 * usefull. 933 */ 934 INP_INFO_RLOCK(&V_tcbinfo); 935 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) { 936 if (inpb->inp_flags & INP_TIMEWAIT) 937 continue; 938 INP_WLOCK(inpb); 939 if ((tcpb = intotcpcb(inpb)) != NULL) { 940 while ((te = LIST_FIRST(&tcpb->t_segq)) 941 != NULL) { 942 LIST_REMOVE(te, tqe_q); 943 m_freem(te->tqe_m); 944 uma_zfree(V_tcp_reass_zone, te); 945 tcpb->t_segqlen--; 946 V_tcp_reass_qsize--; 947 } 948 tcp_clean_sackreport(tcpb); 949 } 950 INP_WUNLOCK(inpb); 951 } 952 INP_INFO_RUNLOCK(&V_tcbinfo); 953 CURVNET_RESTORE(); 954 } 955 VNET_LIST_RUNLOCK_NOSLEEP(); 956 } 957 958 /* 959 * Notify a tcp user of an asynchronous error; 960 * store error as soft error, but wake up user 961 * (for now, won't do anything until can select for soft error). 962 * 963 * Do not wake up user since there currently is no mechanism for 964 * reporting soft errors (yet - a kqueue filter may be added). 965 */ 966 static struct inpcb * 967 tcp_notify(struct inpcb *inp, int error) 968 { 969 struct tcpcb *tp; 970 971 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 972 INP_WLOCK_ASSERT(inp); 973 974 if ((inp->inp_flags & INP_TIMEWAIT) || 975 (inp->inp_flags & INP_DROPPED)) 976 return (inp); 977 978 tp = intotcpcb(inp); 979 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 980 981 /* 982 * Ignore some errors if we are hooked up. 983 * If connection hasn't completed, has retransmitted several times, 984 * and receives a second error, give up now. This is better 985 * than waiting a long time to establish a connection that 986 * can never complete. 987 */ 988 if (tp->t_state == TCPS_ESTABLISHED && 989 (error == EHOSTUNREACH || error == ENETUNREACH || 990 error == EHOSTDOWN)) { 991 return (inp); 992 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 993 tp->t_softerror) { 994 tp = tcp_drop(tp, error); 995 if (tp != NULL) 996 return (inp); 997 else 998 return (NULL); 999 } else { 1000 tp->t_softerror = error; 1001 return (inp); 1002 } 1003 #if 0 1004 wakeup( &so->so_timeo); 1005 sorwakeup(so); 1006 sowwakeup(so); 1007 #endif 1008 } 1009 1010 static int 1011 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1012 { 1013 int error, i, m, n, pcb_count; 1014 struct inpcb *inp, **inp_list; 1015 inp_gen_t gencnt; 1016 struct xinpgen xig; 1017 1018 /* 1019 * The process of preparing the TCB list is too time-consuming and 1020 * resource-intensive to repeat twice on every request. 1021 */ 1022 if (req->oldptr == NULL) { 1023 m = syncache_pcbcount(); 1024 n = V_tcbinfo.ipi_count; 1025 req->oldidx = 2 * (sizeof xig) 1026 + ((m + n) + n/8) * sizeof(struct xtcpcb); 1027 return (0); 1028 } 1029 1030 if (req->newptr != NULL) 1031 return (EPERM); 1032 1033 /* 1034 * OK, now we're committed to doing something. 1035 */ 1036 INP_INFO_RLOCK(&V_tcbinfo); 1037 gencnt = V_tcbinfo.ipi_gencnt; 1038 n = V_tcbinfo.ipi_count; 1039 INP_INFO_RUNLOCK(&V_tcbinfo); 1040 1041 m = syncache_pcbcount(); 1042 1043 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 1044 + (n + m) * sizeof(struct xtcpcb)); 1045 if (error != 0) 1046 return (error); 1047 1048 xig.xig_len = sizeof xig; 1049 xig.xig_count = n + m; 1050 xig.xig_gen = gencnt; 1051 xig.xig_sogen = so_gencnt; 1052 error = SYSCTL_OUT(req, &xig, sizeof xig); 1053 if (error) 1054 return (error); 1055 1056 error = syncache_pcblist(req, m, &pcb_count); 1057 if (error) 1058 return (error); 1059 1060 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 1061 if (inp_list == NULL) 1062 return (ENOMEM); 1063 1064 INP_INFO_RLOCK(&V_tcbinfo); 1065 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0; 1066 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) { 1067 INP_WLOCK(inp); 1068 if (inp->inp_gencnt <= gencnt) { 1069 /* 1070 * XXX: This use of cr_cansee(), introduced with 1071 * TCP state changes, is not quite right, but for 1072 * now, better than nothing. 1073 */ 1074 if (inp->inp_flags & INP_TIMEWAIT) { 1075 if (intotw(inp) != NULL) 1076 error = cr_cansee(req->td->td_ucred, 1077 intotw(inp)->tw_cred); 1078 else 1079 error = EINVAL; /* Skip this inp. */ 1080 } else 1081 error = cr_canseeinpcb(req->td->td_ucred, inp); 1082 if (error == 0) { 1083 in_pcbref(inp); 1084 inp_list[i++] = inp; 1085 } 1086 } 1087 INP_WUNLOCK(inp); 1088 } 1089 INP_INFO_RUNLOCK(&V_tcbinfo); 1090 n = i; 1091 1092 error = 0; 1093 for (i = 0; i < n; i++) { 1094 inp = inp_list[i]; 1095 INP_RLOCK(inp); 1096 if (inp->inp_gencnt <= gencnt) { 1097 struct xtcpcb xt; 1098 void *inp_ppcb; 1099 1100 bzero(&xt, sizeof(xt)); 1101 xt.xt_len = sizeof xt; 1102 /* XXX should avoid extra copy */ 1103 bcopy(inp, &xt.xt_inp, sizeof *inp); 1104 inp_ppcb = inp->inp_ppcb; 1105 if (inp_ppcb == NULL) 1106 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1107 else if (inp->inp_flags & INP_TIMEWAIT) { 1108 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1109 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1110 } else { 1111 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1112 if (xt.xt_tp.t_timers) 1113 tcp_timer_to_xtimer(&xt.xt_tp, xt.xt_tp.t_timers, &xt.xt_timer); 1114 } 1115 if (inp->inp_socket != NULL) 1116 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1117 else { 1118 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1119 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1120 } 1121 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1122 INP_RUNLOCK(inp); 1123 error = SYSCTL_OUT(req, &xt, sizeof xt); 1124 } else 1125 INP_RUNLOCK(inp); 1126 } 1127 INP_INFO_WLOCK(&V_tcbinfo); 1128 for (i = 0; i < n; i++) { 1129 inp = inp_list[i]; 1130 INP_WLOCK(inp); 1131 if (!in_pcbrele(inp)) 1132 INP_WUNLOCK(inp); 1133 } 1134 INP_INFO_WUNLOCK(&V_tcbinfo); 1135 1136 if (!error) { 1137 /* 1138 * Give the user an updated idea of our state. 1139 * If the generation differs from what we told 1140 * her before, she knows that something happened 1141 * while we were processing this request, and it 1142 * might be necessary to retry. 1143 */ 1144 INP_INFO_RLOCK(&V_tcbinfo); 1145 xig.xig_gen = V_tcbinfo.ipi_gencnt; 1146 xig.xig_sogen = so_gencnt; 1147 xig.xig_count = V_tcbinfo.ipi_count + pcb_count; 1148 INP_INFO_RUNLOCK(&V_tcbinfo); 1149 error = SYSCTL_OUT(req, &xig, sizeof xig); 1150 } 1151 free(inp_list, M_TEMP); 1152 return (error); 1153 } 1154 1155 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1156 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1157 1158 static int 1159 tcp_getcred(SYSCTL_HANDLER_ARGS) 1160 { 1161 struct xucred xuc; 1162 struct sockaddr_in addrs[2]; 1163 struct inpcb *inp; 1164 int error; 1165 1166 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1167 if (error) 1168 return (error); 1169 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1170 if (error) 1171 return (error); 1172 INP_INFO_RLOCK(&V_tcbinfo); 1173 inp = in_pcblookup_hash(&V_tcbinfo, addrs[1].sin_addr, 1174 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1175 if (inp != NULL) { 1176 INP_RLOCK(inp); 1177 INP_INFO_RUNLOCK(&V_tcbinfo); 1178 if (inp->inp_socket == NULL) 1179 error = ENOENT; 1180 if (error == 0) 1181 error = cr_canseeinpcb(req->td->td_ucred, inp); 1182 if (error == 0) 1183 cru2x(inp->inp_cred, &xuc); 1184 INP_RUNLOCK(inp); 1185 } else { 1186 INP_INFO_RUNLOCK(&V_tcbinfo); 1187 error = ENOENT; 1188 } 1189 if (error == 0) 1190 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1191 return (error); 1192 } 1193 1194 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1195 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1196 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1197 1198 #ifdef INET6 1199 static int 1200 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1201 { 1202 struct xucred xuc; 1203 struct sockaddr_in6 addrs[2]; 1204 struct inpcb *inp; 1205 int error, mapped = 0; 1206 1207 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1208 if (error) 1209 return (error); 1210 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1211 if (error) 1212 return (error); 1213 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 || 1214 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) { 1215 return (error); 1216 } 1217 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1218 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1219 mapped = 1; 1220 else 1221 return (EINVAL); 1222 } 1223 1224 INP_INFO_RLOCK(&V_tcbinfo); 1225 if (mapped == 1) 1226 inp = in_pcblookup_hash(&V_tcbinfo, 1227 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1228 addrs[1].sin6_port, 1229 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1230 addrs[0].sin6_port, 1231 0, NULL); 1232 else 1233 inp = in6_pcblookup_hash(&V_tcbinfo, 1234 &addrs[1].sin6_addr, addrs[1].sin6_port, 1235 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1236 if (inp != NULL) { 1237 INP_RLOCK(inp); 1238 INP_INFO_RUNLOCK(&V_tcbinfo); 1239 if (inp->inp_socket == NULL) 1240 error = ENOENT; 1241 if (error == 0) 1242 error = cr_canseeinpcb(req->td->td_ucred, inp); 1243 if (error == 0) 1244 cru2x(inp->inp_cred, &xuc); 1245 INP_RUNLOCK(inp); 1246 } else { 1247 INP_INFO_RUNLOCK(&V_tcbinfo); 1248 error = ENOENT; 1249 } 1250 if (error == 0) 1251 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1252 return (error); 1253 } 1254 1255 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1256 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1257 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1258 #endif 1259 1260 1261 void 1262 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1263 { 1264 struct ip *ip = vip; 1265 struct tcphdr *th; 1266 struct in_addr faddr; 1267 struct inpcb *inp; 1268 struct tcpcb *tp; 1269 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1270 struct icmp *icp; 1271 struct in_conninfo inc; 1272 tcp_seq icmp_tcp_seq; 1273 int mtu; 1274 1275 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1276 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1277 return; 1278 1279 if (cmd == PRC_MSGSIZE) 1280 notify = tcp_mtudisc; 1281 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1282 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1283 notify = tcp_drop_syn_sent; 1284 /* 1285 * Redirects don't need to be handled up here. 1286 */ 1287 else if (PRC_IS_REDIRECT(cmd)) 1288 return; 1289 /* 1290 * Source quench is depreciated. 1291 */ 1292 else if (cmd == PRC_QUENCH) 1293 return; 1294 /* 1295 * Hostdead is ugly because it goes linearly through all PCBs. 1296 * XXX: We never get this from ICMP, otherwise it makes an 1297 * excellent DoS attack on machines with many connections. 1298 */ 1299 else if (cmd == PRC_HOSTDEAD) 1300 ip = NULL; 1301 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1302 return; 1303 if (ip != NULL) { 1304 icp = (struct icmp *)((caddr_t)ip 1305 - offsetof(struct icmp, icmp_ip)); 1306 th = (struct tcphdr *)((caddr_t)ip 1307 + (ip->ip_hl << 2)); 1308 INP_INFO_WLOCK(&V_tcbinfo); 1309 inp = in_pcblookup_hash(&V_tcbinfo, faddr, th->th_dport, 1310 ip->ip_src, th->th_sport, 0, NULL); 1311 if (inp != NULL) { 1312 INP_WLOCK(inp); 1313 if (!(inp->inp_flags & INP_TIMEWAIT) && 1314 !(inp->inp_flags & INP_DROPPED) && 1315 !(inp->inp_socket == NULL)) { 1316 icmp_tcp_seq = htonl(th->th_seq); 1317 tp = intotcpcb(inp); 1318 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1319 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1320 if (cmd == PRC_MSGSIZE) { 1321 /* 1322 * MTU discovery: 1323 * If we got a needfrag set the MTU 1324 * in the route to the suggested new 1325 * value (if given) and then notify. 1326 */ 1327 bzero(&inc, sizeof(inc)); 1328 inc.inc_faddr = faddr; 1329 inc.inc_fibnum = 1330 inp->inp_inc.inc_fibnum; 1331 1332 mtu = ntohs(icp->icmp_nextmtu); 1333 /* 1334 * If no alternative MTU was 1335 * proposed, try the next smaller 1336 * one. ip->ip_len has already 1337 * been swapped in icmp_input(). 1338 */ 1339 if (!mtu) 1340 mtu = ip_next_mtu(ip->ip_len, 1341 1); 1342 if (mtu < max(296, V_tcp_minmss 1343 + sizeof(struct tcpiphdr))) 1344 mtu = 0; 1345 if (!mtu) 1346 mtu = V_tcp_mssdflt 1347 + sizeof(struct tcpiphdr); 1348 /* 1349 * Only cache the the MTU if it 1350 * is smaller than the interface 1351 * or route MTU. tcp_mtudisc() 1352 * will do right thing by itself. 1353 */ 1354 if (mtu <= tcp_maxmtu(&inc, NULL)) 1355 tcp_hc_updatemtu(&inc, mtu); 1356 } 1357 1358 inp = (*notify)(inp, inetctlerrmap[cmd]); 1359 } 1360 } 1361 if (inp != NULL) 1362 INP_WUNLOCK(inp); 1363 } else { 1364 bzero(&inc, sizeof(inc)); 1365 inc.inc_fport = th->th_dport; 1366 inc.inc_lport = th->th_sport; 1367 inc.inc_faddr = faddr; 1368 inc.inc_laddr = ip->ip_src; 1369 syncache_unreach(&inc, th); 1370 } 1371 INP_INFO_WUNLOCK(&V_tcbinfo); 1372 } else 1373 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify); 1374 } 1375 1376 #ifdef INET6 1377 void 1378 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1379 { 1380 struct tcphdr th; 1381 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1382 struct ip6_hdr *ip6; 1383 struct mbuf *m; 1384 struct ip6ctlparam *ip6cp = NULL; 1385 const struct sockaddr_in6 *sa6_src = NULL; 1386 int off; 1387 struct tcp_portonly { 1388 u_int16_t th_sport; 1389 u_int16_t th_dport; 1390 } *thp; 1391 1392 if (sa->sa_family != AF_INET6 || 1393 sa->sa_len != sizeof(struct sockaddr_in6)) 1394 return; 1395 1396 if (cmd == PRC_MSGSIZE) 1397 notify = tcp_mtudisc; 1398 else if (!PRC_IS_REDIRECT(cmd) && 1399 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1400 return; 1401 /* Source quench is depreciated. */ 1402 else if (cmd == PRC_QUENCH) 1403 return; 1404 1405 /* if the parameter is from icmp6, decode it. */ 1406 if (d != NULL) { 1407 ip6cp = (struct ip6ctlparam *)d; 1408 m = ip6cp->ip6c_m; 1409 ip6 = ip6cp->ip6c_ip6; 1410 off = ip6cp->ip6c_off; 1411 sa6_src = ip6cp->ip6c_src; 1412 } else { 1413 m = NULL; 1414 ip6 = NULL; 1415 off = 0; /* fool gcc */ 1416 sa6_src = &sa6_any; 1417 } 1418 1419 if (ip6 != NULL) { 1420 struct in_conninfo inc; 1421 /* 1422 * XXX: We assume that when IPV6 is non NULL, 1423 * M and OFF are valid. 1424 */ 1425 1426 /* check if we can safely examine src and dst ports */ 1427 if (m->m_pkthdr.len < off + sizeof(*thp)) 1428 return; 1429 1430 bzero(&th, sizeof(th)); 1431 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1432 1433 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport, 1434 (struct sockaddr *)ip6cp->ip6c_src, 1435 th.th_sport, cmd, NULL, notify); 1436 1437 bzero(&inc, sizeof(inc)); 1438 inc.inc_fport = th.th_dport; 1439 inc.inc_lport = th.th_sport; 1440 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1441 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1442 inc.inc_flags |= INC_ISIPV6; 1443 INP_INFO_WLOCK(&V_tcbinfo); 1444 syncache_unreach(&inc, &th); 1445 INP_INFO_WUNLOCK(&V_tcbinfo); 1446 } else 1447 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1448 0, cmd, NULL, notify); 1449 } 1450 #endif /* INET6 */ 1451 1452 1453 /* 1454 * Following is where TCP initial sequence number generation occurs. 1455 * 1456 * There are two places where we must use initial sequence numbers: 1457 * 1. In SYN-ACK packets. 1458 * 2. In SYN packets. 1459 * 1460 * All ISNs for SYN-ACK packets are generated by the syncache. See 1461 * tcp_syncache.c for details. 1462 * 1463 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1464 * depends on this property. In addition, these ISNs should be 1465 * unguessable so as to prevent connection hijacking. To satisfy 1466 * the requirements of this situation, the algorithm outlined in 1467 * RFC 1948 is used, with only small modifications. 1468 * 1469 * Implementation details: 1470 * 1471 * Time is based off the system timer, and is corrected so that it 1472 * increases by one megabyte per second. This allows for proper 1473 * recycling on high speed LANs while still leaving over an hour 1474 * before rollover. 1475 * 1476 * As reading the *exact* system time is too expensive to be done 1477 * whenever setting up a TCP connection, we increment the time 1478 * offset in two ways. First, a small random positive increment 1479 * is added to isn_offset for each connection that is set up. 1480 * Second, the function tcp_isn_tick fires once per clock tick 1481 * and increments isn_offset as necessary so that sequence numbers 1482 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1483 * random positive increments serve only to ensure that the same 1484 * exact sequence number is never sent out twice (as could otherwise 1485 * happen when a port is recycled in less than the system tick 1486 * interval.) 1487 * 1488 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1489 * between seeding of isn_secret. This is normally set to zero, 1490 * as reseeding should not be necessary. 1491 * 1492 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1493 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1494 * general, this means holding an exclusive (write) lock. 1495 */ 1496 1497 #define ISN_BYTES_PER_SECOND 1048576 1498 #define ISN_STATIC_INCREMENT 4096 1499 #define ISN_RANDOM_INCREMENT (4096 - 1) 1500 1501 static VNET_DEFINE(u_char, isn_secret[32]); 1502 static VNET_DEFINE(int, isn_last_reseed); 1503 static VNET_DEFINE(u_int32_t, isn_offset); 1504 static VNET_DEFINE(u_int32_t, isn_offset_old); 1505 1506 #define V_isn_secret VNET(isn_secret) 1507 #define V_isn_last_reseed VNET(isn_last_reseed) 1508 #define V_isn_offset VNET(isn_offset) 1509 #define V_isn_offset_old VNET(isn_offset_old) 1510 1511 tcp_seq 1512 tcp_new_isn(struct tcpcb *tp) 1513 { 1514 MD5_CTX isn_ctx; 1515 u_int32_t md5_buffer[4]; 1516 tcp_seq new_isn; 1517 1518 INP_WLOCK_ASSERT(tp->t_inpcb); 1519 1520 ISN_LOCK(); 1521 /* Seed if this is the first use, reseed if requested. */ 1522 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) && 1523 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz) 1524 < (u_int)ticks))) { 1525 read_random(&V_isn_secret, sizeof(V_isn_secret)); 1526 V_isn_last_reseed = ticks; 1527 } 1528 1529 /* Compute the md5 hash and return the ISN. */ 1530 MD5Init(&isn_ctx); 1531 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1532 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1533 #ifdef INET6 1534 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1535 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1536 sizeof(struct in6_addr)); 1537 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1538 sizeof(struct in6_addr)); 1539 } else 1540 #endif 1541 { 1542 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1543 sizeof(struct in_addr)); 1544 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1545 sizeof(struct in_addr)); 1546 } 1547 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret)); 1548 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1549 new_isn = (tcp_seq) md5_buffer[0]; 1550 V_isn_offset += ISN_STATIC_INCREMENT + 1551 (arc4random() & ISN_RANDOM_INCREMENT); 1552 new_isn += V_isn_offset; 1553 ISN_UNLOCK(); 1554 return (new_isn); 1555 } 1556 1557 /* 1558 * Increment the offset to the next ISN_BYTES_PER_SECOND / 100 boundary 1559 * to keep time flowing at a relatively constant rate. If the random 1560 * increments have already pushed us past the projected offset, do nothing. 1561 */ 1562 static void 1563 tcp_isn_tick(void *xtp) 1564 { 1565 VNET_ITERATOR_DECL(vnet_iter); 1566 u_int32_t projected_offset; 1567 1568 VNET_LIST_RLOCK_NOSLEEP(); 1569 ISN_LOCK(); 1570 VNET_FOREACH(vnet_iter) { 1571 CURVNET_SET(vnet_iter); /* XXX appease INVARIANTS */ 1572 projected_offset = 1573 V_isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1574 1575 if (SEQ_GT(projected_offset, V_isn_offset)) 1576 V_isn_offset = projected_offset; 1577 1578 V_isn_offset_old = V_isn_offset; 1579 CURVNET_RESTORE(); 1580 } 1581 ISN_UNLOCK(); 1582 VNET_LIST_RUNLOCK_NOSLEEP(); 1583 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1584 } 1585 1586 /* 1587 * When a specific ICMP unreachable message is received and the 1588 * connection state is SYN-SENT, drop the connection. This behavior 1589 * is controlled by the icmp_may_rst sysctl. 1590 */ 1591 struct inpcb * 1592 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1593 { 1594 struct tcpcb *tp; 1595 1596 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 1597 INP_WLOCK_ASSERT(inp); 1598 1599 if ((inp->inp_flags & INP_TIMEWAIT) || 1600 (inp->inp_flags & INP_DROPPED)) 1601 return (inp); 1602 1603 tp = intotcpcb(inp); 1604 if (tp->t_state != TCPS_SYN_SENT) 1605 return (inp); 1606 1607 tp = tcp_drop(tp, errno); 1608 if (tp != NULL) 1609 return (inp); 1610 else 1611 return (NULL); 1612 } 1613 1614 /* 1615 * When `need fragmentation' ICMP is received, update our idea of the MSS 1616 * based on the new value in the route. Also nudge TCP to send something, 1617 * since we know the packet we just sent was dropped. 1618 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1619 */ 1620 struct inpcb * 1621 tcp_mtudisc(struct inpcb *inp, int errno) 1622 { 1623 struct tcpcb *tp; 1624 struct socket *so; 1625 1626 INP_WLOCK_ASSERT(inp); 1627 if ((inp->inp_flags & INP_TIMEWAIT) || 1628 (inp->inp_flags & INP_DROPPED)) 1629 return (inp); 1630 1631 tp = intotcpcb(inp); 1632 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1633 1634 tcp_mss_update(tp, -1, NULL, NULL); 1635 1636 so = inp->inp_socket; 1637 SOCKBUF_LOCK(&so->so_snd); 1638 /* If the mss is larger than the socket buffer, decrease the mss. */ 1639 if (so->so_snd.sb_hiwat < tp->t_maxseg) 1640 tp->t_maxseg = so->so_snd.sb_hiwat; 1641 SOCKBUF_UNLOCK(&so->so_snd); 1642 1643 TCPSTAT_INC(tcps_mturesent); 1644 tp->t_rtttime = 0; 1645 tp->snd_nxt = tp->snd_una; 1646 tcp_free_sackholes(tp); 1647 tp->snd_recover = tp->snd_max; 1648 if (tp->t_flags & TF_SACK_PERMIT) 1649 EXIT_FASTRECOVERY(tp); 1650 tcp_output_send(tp); 1651 return (inp); 1652 } 1653 1654 /* 1655 * Look-up the routing entry to the peer of this inpcb. If no route 1656 * is found and it cannot be allocated, then return 0. This routine 1657 * is called by TCP routines that access the rmx structure and by 1658 * tcp_mss_update to get the peer/interface MTU. 1659 */ 1660 u_long 1661 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1662 { 1663 struct route sro; 1664 struct sockaddr_in *dst; 1665 struct ifnet *ifp; 1666 u_long maxmtu = 0; 1667 1668 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1669 1670 bzero(&sro, sizeof(sro)); 1671 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1672 dst = (struct sockaddr_in *)&sro.ro_dst; 1673 dst->sin_family = AF_INET; 1674 dst->sin_len = sizeof(*dst); 1675 dst->sin_addr = inc->inc_faddr; 1676 in_rtalloc_ign(&sro, 0, inc->inc_fibnum); 1677 } 1678 if (sro.ro_rt != NULL) { 1679 ifp = sro.ro_rt->rt_ifp; 1680 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1681 maxmtu = ifp->if_mtu; 1682 else 1683 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1684 1685 /* Report additional interface capabilities. */ 1686 if (flags != NULL) { 1687 if (ifp->if_capenable & IFCAP_TSO4 && 1688 ifp->if_hwassist & CSUM_TSO) 1689 *flags |= CSUM_TSO; 1690 } 1691 RTFREE(sro.ro_rt); 1692 } 1693 return (maxmtu); 1694 } 1695 1696 #ifdef INET6 1697 u_long 1698 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1699 { 1700 struct route_in6 sro6; 1701 struct ifnet *ifp; 1702 u_long maxmtu = 0; 1703 1704 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1705 1706 bzero(&sro6, sizeof(sro6)); 1707 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1708 sro6.ro_dst.sin6_family = AF_INET6; 1709 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1710 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1711 rtalloc_ign((struct route *)&sro6, 0); 1712 } 1713 if (sro6.ro_rt != NULL) { 1714 ifp = sro6.ro_rt->rt_ifp; 1715 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1716 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1717 else 1718 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1719 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1720 1721 /* Report additional interface capabilities. */ 1722 if (flags != NULL) { 1723 if (ifp->if_capenable & IFCAP_TSO6 && 1724 ifp->if_hwassist & CSUM_TSO) 1725 *flags |= CSUM_TSO; 1726 } 1727 RTFREE(sro6.ro_rt); 1728 } 1729 1730 return (maxmtu); 1731 } 1732 #endif /* INET6 */ 1733 1734 #ifdef IPSEC 1735 /* compute ESP/AH header size for TCP, including outer IP header. */ 1736 size_t 1737 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1738 { 1739 struct inpcb *inp; 1740 struct mbuf *m; 1741 size_t hdrsiz; 1742 struct ip *ip; 1743 #ifdef INET6 1744 struct ip6_hdr *ip6; 1745 #endif 1746 struct tcphdr *th; 1747 1748 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1749 return (0); 1750 MGETHDR(m, M_DONTWAIT, MT_DATA); 1751 if (!m) 1752 return (0); 1753 1754 #ifdef INET6 1755 if ((inp->inp_vflag & INP_IPV6) != 0) { 1756 ip6 = mtod(m, struct ip6_hdr *); 1757 th = (struct tcphdr *)(ip6 + 1); 1758 m->m_pkthdr.len = m->m_len = 1759 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1760 tcpip_fillheaders(inp, ip6, th); 1761 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1762 } else 1763 #endif /* INET6 */ 1764 { 1765 ip = mtod(m, struct ip *); 1766 th = (struct tcphdr *)(ip + 1); 1767 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1768 tcpip_fillheaders(inp, ip, th); 1769 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1770 } 1771 1772 m_free(m); 1773 return (hdrsiz); 1774 } 1775 #endif /* IPSEC */ 1776 1777 /* 1778 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1779 * 1780 * This code attempts to calculate the bandwidth-delay product as a 1781 * means of determining the optimal window size to maximize bandwidth, 1782 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1783 * routers. This code also does a fairly good job keeping RTTs in check 1784 * across slow links like modems. We implement an algorithm which is very 1785 * similar (but not meant to be) TCP/Vegas. The code operates on the 1786 * transmitter side of a TCP connection and so only effects the transmit 1787 * side of the connection. 1788 * 1789 * BACKGROUND: TCP makes no provision for the management of buffer space 1790 * at the end points or at the intermediate routers and switches. A TCP 1791 * stream, whether using NewReno or not, will eventually buffer as 1792 * many packets as it is able and the only reason this typically works is 1793 * due to the fairly small default buffers made available for a connection 1794 * (typicaly 16K or 32K). As machines use larger windows and/or window 1795 * scaling it is now fairly easy for even a single TCP connection to blow-out 1796 * all available buffer space not only on the local interface, but on 1797 * intermediate routers and switches as well. NewReno makes a misguided 1798 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1799 * then backing off, then steadily increasing the window again until another 1800 * failure occurs, ad-infinitum. This results in terrible oscillation that 1801 * is only made worse as network loads increase and the idea of intentionally 1802 * blowing out network buffers is, frankly, a terrible way to manage network 1803 * resources. 1804 * 1805 * It is far better to limit the transmit window prior to the failure 1806 * condition being achieved. There are two general ways to do this: First 1807 * you can 'scan' through different transmit window sizes and locate the 1808 * point where the RTT stops increasing, indicating that you have filled the 1809 * pipe, then scan backwards until you note that RTT stops decreasing, then 1810 * repeat ad-infinitum. This method works in principle but has severe 1811 * implementation issues due to RTT variances, timer granularity, and 1812 * instability in the algorithm which can lead to many false positives and 1813 * create oscillations as well as interact badly with other TCP streams 1814 * implementing the same algorithm. 1815 * 1816 * The second method is to limit the window to the bandwidth delay product 1817 * of the link. This is the method we implement. RTT variances and our 1818 * own manipulation of the congestion window, bwnd, can potentially 1819 * destabilize the algorithm. For this reason we have to stabilize the 1820 * elements used to calculate the window. We do this by using the minimum 1821 * observed RTT, the long term average of the observed bandwidth, and 1822 * by adding two segments worth of slop. It isn't perfect but it is able 1823 * to react to changing conditions and gives us a very stable basis on 1824 * which to extend the algorithm. 1825 */ 1826 void 1827 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1828 { 1829 u_long bw; 1830 u_long bwnd; 1831 int save_ticks; 1832 1833 INP_WLOCK_ASSERT(tp->t_inpcb); 1834 1835 /* 1836 * If inflight_enable is disabled in the middle of a tcp connection, 1837 * make sure snd_bwnd is effectively disabled. 1838 */ 1839 if (V_tcp_inflight_enable == 0 || 1840 tp->t_rttlow < V_tcp_inflight_rttthresh) { 1841 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1842 tp->snd_bandwidth = 0; 1843 return; 1844 } 1845 1846 /* 1847 * Figure out the bandwidth. Due to the tick granularity this 1848 * is a very rough number and it MUST be averaged over a fairly 1849 * long period of time. XXX we need to take into account a link 1850 * that is not using all available bandwidth, but for now our 1851 * slop will ramp us up if this case occurs and the bandwidth later 1852 * increases. 1853 * 1854 * Note: if ticks rollover 'bw' may wind up negative. We must 1855 * effectively reset t_bw_rtttime for this case. 1856 */ 1857 save_ticks = ticks; 1858 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 1859 return; 1860 1861 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 1862 (save_ticks - tp->t_bw_rtttime); 1863 tp->t_bw_rtttime = save_ticks; 1864 tp->t_bw_rtseq = ack_seq; 1865 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 1866 return; 1867 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1868 1869 tp->snd_bandwidth = bw; 1870 1871 /* 1872 * Calculate the semi-static bandwidth delay product, plus two maximal 1873 * segments. The additional slop puts us squarely in the sweet 1874 * spot and also handles the bandwidth run-up case and stabilization. 1875 * Without the slop we could be locking ourselves into a lower 1876 * bandwidth. 1877 * 1878 * Situations Handled: 1879 * (1) Prevents over-queueing of packets on LANs, especially on 1880 * high speed LANs, allowing larger TCP buffers to be 1881 * specified, and also does a good job preventing 1882 * over-queueing of packets over choke points like modems 1883 * (at least for the transmit side). 1884 * 1885 * (2) Is able to handle changing network loads (bandwidth 1886 * drops so bwnd drops, bandwidth increases so bwnd 1887 * increases). 1888 * 1889 * (3) Theoretically should stabilize in the face of multiple 1890 * connections implementing the same algorithm (this may need 1891 * a little work). 1892 * 1893 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1894 * be adjusted with a sysctl but typically only needs to be 1895 * on very slow connections. A value no smaller then 5 1896 * should be used, but only reduce this default if you have 1897 * no other choice. 1898 */ 1899 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1900 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + V_tcp_inflight_stab * tp->t_maxseg / 10; 1901 #undef USERTT 1902 1903 if (tcp_inflight_debug > 0) { 1904 static int ltime; 1905 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1906 ltime = ticks; 1907 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1908 tp, 1909 bw, 1910 tp->t_rttbest, 1911 tp->t_srtt, 1912 bwnd 1913 ); 1914 } 1915 } 1916 if ((long)bwnd < V_tcp_inflight_min) 1917 bwnd = V_tcp_inflight_min; 1918 if (bwnd > V_tcp_inflight_max) 1919 bwnd = V_tcp_inflight_max; 1920 if ((long)bwnd < tp->t_maxseg * 2) 1921 bwnd = tp->t_maxseg * 2; 1922 tp->snd_bwnd = bwnd; 1923 } 1924 1925 #ifdef TCP_SIGNATURE 1926 /* 1927 * Callback function invoked by m_apply() to digest TCP segment data 1928 * contained within an mbuf chain. 1929 */ 1930 static int 1931 tcp_signature_apply(void *fstate, void *data, u_int len) 1932 { 1933 1934 MD5Update(fstate, (u_char *)data, len); 1935 return (0); 1936 } 1937 1938 /* 1939 * Compute TCP-MD5 hash of a TCP segment. (RFC2385) 1940 * 1941 * Parameters: 1942 * m pointer to head of mbuf chain 1943 * _unused 1944 * len length of TCP segment data, excluding options 1945 * optlen length of TCP segment options 1946 * buf pointer to storage for computed MD5 digest 1947 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 1948 * 1949 * We do this over ip, tcphdr, segment data, and the key in the SADB. 1950 * When called from tcp_input(), we can be sure that th_sum has been 1951 * zeroed out and verified already. 1952 * 1953 * Return 0 if successful, otherwise return -1. 1954 * 1955 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 1956 * search with the destination IP address, and a 'magic SPI' to be 1957 * determined by the application. This is hardcoded elsewhere to 1179 1958 * right now. Another branch of this code exists which uses the SPD to 1959 * specify per-application flows but it is unstable. 1960 */ 1961 int 1962 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen, 1963 u_char *buf, u_int direction) 1964 { 1965 union sockaddr_union dst; 1966 struct ippseudo ippseudo; 1967 MD5_CTX ctx; 1968 int doff; 1969 struct ip *ip; 1970 struct ipovly *ipovly; 1971 struct secasvar *sav; 1972 struct tcphdr *th; 1973 #ifdef INET6 1974 struct ip6_hdr *ip6; 1975 struct in6_addr in6; 1976 char ip6buf[INET6_ADDRSTRLEN]; 1977 uint32_t plen; 1978 uint16_t nhdr; 1979 #endif 1980 u_short savecsum; 1981 1982 KASSERT(m != NULL, ("NULL mbuf chain")); 1983 KASSERT(buf != NULL, ("NULL signature pointer")); 1984 1985 /* Extract the destination from the IP header in the mbuf. */ 1986 bzero(&dst, sizeof(union sockaddr_union)); 1987 ip = mtod(m, struct ip *); 1988 #ifdef INET6 1989 ip6 = NULL; /* Make the compiler happy. */ 1990 #endif 1991 switch (ip->ip_v) { 1992 case IPVERSION: 1993 dst.sa.sa_len = sizeof(struct sockaddr_in); 1994 dst.sa.sa_family = AF_INET; 1995 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 1996 ip->ip_src : ip->ip_dst; 1997 break; 1998 #ifdef INET6 1999 case (IPV6_VERSION >> 4): 2000 ip6 = mtod(m, struct ip6_hdr *); 2001 dst.sa.sa_len = sizeof(struct sockaddr_in6); 2002 dst.sa.sa_family = AF_INET6; 2003 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ? 2004 ip6->ip6_src : ip6->ip6_dst; 2005 break; 2006 #endif 2007 default: 2008 return (EINVAL); 2009 /* NOTREACHED */ 2010 break; 2011 } 2012 2013 /* Look up an SADB entry which matches the address of the peer. */ 2014 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2015 if (sav == NULL) { 2016 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__, 2017 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) : 2018 #ifdef INET6 2019 (ip->ip_v == (IPV6_VERSION >> 4)) ? 2020 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) : 2021 #endif 2022 "(unsupported)")); 2023 return (EINVAL); 2024 } 2025 2026 MD5Init(&ctx); 2027 /* 2028 * Step 1: Update MD5 hash with IP(v6) pseudo-header. 2029 * 2030 * XXX The ippseudo header MUST be digested in network byte order, 2031 * or else we'll fail the regression test. Assume all fields we've 2032 * been doing arithmetic on have been in host byte order. 2033 * XXX One cannot depend on ipovly->ih_len here. When called from 2034 * tcp_output(), the underlying ip_len member has not yet been set. 2035 */ 2036 switch (ip->ip_v) { 2037 case IPVERSION: 2038 ipovly = (struct ipovly *)ip; 2039 ippseudo.ippseudo_src = ipovly->ih_src; 2040 ippseudo.ippseudo_dst = ipovly->ih_dst; 2041 ippseudo.ippseudo_pad = 0; 2042 ippseudo.ippseudo_p = IPPROTO_TCP; 2043 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + 2044 optlen); 2045 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2046 2047 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip)); 2048 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen; 2049 break; 2050 #ifdef INET6 2051 /* 2052 * RFC 2385, 2.0 Proposal 2053 * For IPv6, the pseudo-header is as described in RFC 2460, namely the 2054 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero- 2055 * extended next header value (to form 32 bits), and 32-bit segment 2056 * length. 2057 * Note: Upper-Layer Packet Length comes before Next Header. 2058 */ 2059 case (IPV6_VERSION >> 4): 2060 in6 = ip6->ip6_src; 2061 in6_clearscope(&in6); 2062 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2063 in6 = ip6->ip6_dst; 2064 in6_clearscope(&in6); 2065 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2066 plen = htonl(len + sizeof(struct tcphdr) + optlen); 2067 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t)); 2068 nhdr = 0; 2069 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2070 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2071 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2072 nhdr = IPPROTO_TCP; 2073 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2074 2075 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr)); 2076 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen; 2077 break; 2078 #endif 2079 default: 2080 return (EINVAL); 2081 /* NOTREACHED */ 2082 break; 2083 } 2084 2085 2086 /* 2087 * Step 2: Update MD5 hash with TCP header, excluding options. 2088 * The TCP checksum must be set to zero. 2089 */ 2090 savecsum = th->th_sum; 2091 th->th_sum = 0; 2092 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2093 th->th_sum = savecsum; 2094 2095 /* 2096 * Step 3: Update MD5 hash with TCP segment data. 2097 * Use m_apply() to avoid an early m_pullup(). 2098 */ 2099 if (len > 0) 2100 m_apply(m, doff, len, tcp_signature_apply, &ctx); 2101 2102 /* 2103 * Step 4: Update MD5 hash with shared secret. 2104 */ 2105 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 2106 MD5Final(buf, &ctx); 2107 2108 key_sa_recordxfer(sav, m); 2109 KEY_FREESAV(&sav); 2110 return (0); 2111 } 2112 #endif /* TCP_SIGNATURE */ 2113 2114 static int 2115 sysctl_drop(SYSCTL_HANDLER_ARGS) 2116 { 2117 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 2118 struct sockaddr_storage addrs[2]; 2119 struct inpcb *inp; 2120 struct tcpcb *tp; 2121 struct tcptw *tw; 2122 struct sockaddr_in *fin, *lin; 2123 #ifdef INET6 2124 struct sockaddr_in6 *fin6, *lin6; 2125 #endif 2126 int error; 2127 2128 inp = NULL; 2129 fin = lin = NULL; 2130 #ifdef INET6 2131 fin6 = lin6 = NULL; 2132 #endif 2133 error = 0; 2134 2135 if (req->oldptr != NULL || req->oldlen != 0) 2136 return (EINVAL); 2137 if (req->newptr == NULL) 2138 return (EPERM); 2139 if (req->newlen < sizeof(addrs)) 2140 return (ENOMEM); 2141 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2142 if (error) 2143 return (error); 2144 2145 switch (addrs[0].ss_family) { 2146 #ifdef INET6 2147 case AF_INET6: 2148 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2149 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2150 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2151 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2152 return (EINVAL); 2153 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2154 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2155 return (EINVAL); 2156 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2157 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2158 fin = (struct sockaddr_in *)&addrs[0]; 2159 lin = (struct sockaddr_in *)&addrs[1]; 2160 break; 2161 } 2162 error = sa6_embedscope(fin6, V_ip6_use_defzone); 2163 if (error) 2164 return (error); 2165 error = sa6_embedscope(lin6, V_ip6_use_defzone); 2166 if (error) 2167 return (error); 2168 break; 2169 #endif 2170 case AF_INET: 2171 fin = (struct sockaddr_in *)&addrs[0]; 2172 lin = (struct sockaddr_in *)&addrs[1]; 2173 if (fin->sin_len != sizeof(struct sockaddr_in) || 2174 lin->sin_len != sizeof(struct sockaddr_in)) 2175 return (EINVAL); 2176 break; 2177 default: 2178 return (EINVAL); 2179 } 2180 INP_INFO_WLOCK(&V_tcbinfo); 2181 switch (addrs[0].ss_family) { 2182 #ifdef INET6 2183 case AF_INET6: 2184 inp = in6_pcblookup_hash(&V_tcbinfo, &fin6->sin6_addr, 2185 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port, 0, 2186 NULL); 2187 break; 2188 #endif 2189 case AF_INET: 2190 inp = in_pcblookup_hash(&V_tcbinfo, fin->sin_addr, 2191 fin->sin_port, lin->sin_addr, lin->sin_port, 0, NULL); 2192 break; 2193 } 2194 if (inp != NULL) { 2195 INP_WLOCK(inp); 2196 if (inp->inp_flags & INP_TIMEWAIT) { 2197 /* 2198 * XXXRW: There currently exists a state where an 2199 * inpcb is present, but its timewait state has been 2200 * discarded. For now, don't allow dropping of this 2201 * type of inpcb. 2202 */ 2203 tw = intotw(inp); 2204 if (tw != NULL) 2205 tcp_twclose(tw, 0); 2206 else 2207 INP_WUNLOCK(inp); 2208 } else if (!(inp->inp_flags & INP_DROPPED) && 2209 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2210 tp = intotcpcb(inp); 2211 tp = tcp_drop(tp, ECONNABORTED); 2212 if (tp != NULL) 2213 INP_WUNLOCK(inp); 2214 } else 2215 INP_WUNLOCK(inp); 2216 } else 2217 error = ESRCH; 2218 INP_INFO_WUNLOCK(&V_tcbinfo); 2219 return (error); 2220 } 2221 2222 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2223 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2224 0, sysctl_drop, "", "Drop TCP connection"); 2225 2226 /* 2227 * Generate a standardized TCP log line for use throughout the 2228 * tcp subsystem. Memory allocation is done with M_NOWAIT to 2229 * allow use in the interrupt context. 2230 * 2231 * NB: The caller MUST free(s, M_TCPLOG) the returned string. 2232 * NB: The function may return NULL if memory allocation failed. 2233 * 2234 * Due to header inclusion and ordering limitations the struct ip 2235 * and ip6_hdr pointers have to be passed as void pointers. 2236 */ 2237 char * 2238 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2239 const void *ip6hdr) 2240 { 2241 char *s, *sp; 2242 size_t size; 2243 struct ip *ip; 2244 #ifdef INET6 2245 const struct ip6_hdr *ip6; 2246 2247 ip6 = (const struct ip6_hdr *)ip6hdr; 2248 #endif /* INET6 */ 2249 ip = (struct ip *)ip4hdr; 2250 2251 /* 2252 * The log line looks like this: 2253 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>" 2254 */ 2255 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") + 2256 sizeof(PRINT_TH_FLAGS) + 1 + 2257 #ifdef INET6 2258 2 * INET6_ADDRSTRLEN; 2259 #else 2260 2 * INET_ADDRSTRLEN; 2261 #endif /* INET6 */ 2262 2263 /* Is logging enabled? */ 2264 if (tcp_log_debug == 0 && tcp_log_in_vain == 0) 2265 return (NULL); 2266 2267 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT); 2268 if (s == NULL) 2269 return (NULL); 2270 2271 strcat(s, "TCP: ["); 2272 sp = s + strlen(s); 2273 2274 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) { 2275 inet_ntoa_r(inc->inc_faddr, sp); 2276 sp = s + strlen(s); 2277 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2278 sp = s + strlen(s); 2279 inet_ntoa_r(inc->inc_laddr, sp); 2280 sp = s + strlen(s); 2281 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2282 #ifdef INET6 2283 } else if (inc) { 2284 ip6_sprintf(sp, &inc->inc6_faddr); 2285 sp = s + strlen(s); 2286 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2287 sp = s + strlen(s); 2288 ip6_sprintf(sp, &inc->inc6_laddr); 2289 sp = s + strlen(s); 2290 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2291 } else if (ip6 && th) { 2292 ip6_sprintf(sp, &ip6->ip6_src); 2293 sp = s + strlen(s); 2294 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2295 sp = s + strlen(s); 2296 ip6_sprintf(sp, &ip6->ip6_dst); 2297 sp = s + strlen(s); 2298 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2299 #endif /* INET6 */ 2300 } else if (ip && th) { 2301 inet_ntoa_r(ip->ip_src, sp); 2302 sp = s + strlen(s); 2303 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2304 sp = s + strlen(s); 2305 inet_ntoa_r(ip->ip_dst, sp); 2306 sp = s + strlen(s); 2307 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2308 } else { 2309 free(s, M_TCPLOG); 2310 return (NULL); 2311 } 2312 sp = s + strlen(s); 2313 if (th) 2314 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS); 2315 if (*(s + size - 1) != '\0') 2316 panic("%s: string too long", __func__); 2317 return (s); 2318 } 2319