1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_compat.h" 36 #include "opt_inet.h" 37 #include "opt_inet6.h" 38 #include "opt_ipsec.h" 39 #include "opt_tcpdebug.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/callout.h> 44 #include <sys/hhook.h> 45 #include <sys/kernel.h> 46 #include <sys/khelp.h> 47 #include <sys/sysctl.h> 48 #include <sys/jail.h> 49 #include <sys/malloc.h> 50 #include <sys/mbuf.h> 51 #ifdef INET6 52 #include <sys/domain.h> 53 #endif 54 #include <sys/priv.h> 55 #include <sys/proc.h> 56 #include <sys/socket.h> 57 #include <sys/socketvar.h> 58 #include <sys/protosw.h> 59 #include <sys/random.h> 60 61 #include <vm/uma.h> 62 63 #include <net/route.h> 64 #include <net/if.h> 65 #include <net/vnet.h> 66 67 #include <netinet/cc.h> 68 #include <netinet/in.h> 69 #include <netinet/in_pcb.h> 70 #include <netinet/in_systm.h> 71 #include <netinet/in_var.h> 72 #include <netinet/ip.h> 73 #include <netinet/ip_icmp.h> 74 #include <netinet/ip_var.h> 75 #ifdef INET6 76 #include <netinet/ip6.h> 77 #include <netinet6/in6_pcb.h> 78 #include <netinet6/ip6_var.h> 79 #include <netinet6/scope6_var.h> 80 #include <netinet6/nd6.h> 81 #endif 82 83 #include <netinet/tcp_fsm.h> 84 #include <netinet/tcp_seq.h> 85 #include <netinet/tcp_timer.h> 86 #include <netinet/tcp_var.h> 87 #include <netinet/tcp_syncache.h> 88 #include <netinet/tcp_offload.h> 89 #ifdef INET6 90 #include <netinet6/tcp6_var.h> 91 #endif 92 #include <netinet/tcpip.h> 93 #ifdef TCPDEBUG 94 #include <netinet/tcp_debug.h> 95 #endif 96 #ifdef INET6 97 #include <netinet6/ip6protosw.h> 98 #endif 99 100 #ifdef IPSEC 101 #include <netipsec/ipsec.h> 102 #include <netipsec/xform.h> 103 #ifdef INET6 104 #include <netipsec/ipsec6.h> 105 #endif 106 #include <netipsec/key.h> 107 #include <sys/syslog.h> 108 #endif /*IPSEC*/ 109 110 #include <machine/in_cksum.h> 111 #include <sys/md5.h> 112 113 #include <security/mac/mac_framework.h> 114 115 VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS; 116 #ifdef INET6 117 VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS; 118 #endif 119 120 static int 121 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS) 122 { 123 int error, new; 124 125 new = V_tcp_mssdflt; 126 error = sysctl_handle_int(oidp, &new, 0, req); 127 if (error == 0 && req->newptr) { 128 if (new < TCP_MINMSS) 129 error = EINVAL; 130 else 131 V_tcp_mssdflt = new; 132 } 133 return (error); 134 } 135 136 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, 137 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_mssdflt), 0, 138 &sysctl_net_inet_tcp_mss_check, "I", 139 "Default TCP Maximum Segment Size"); 140 141 #ifdef INET6 142 static int 143 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS) 144 { 145 int error, new; 146 147 new = V_tcp_v6mssdflt; 148 error = sysctl_handle_int(oidp, &new, 0, req); 149 if (error == 0 && req->newptr) { 150 if (new < TCP_MINMSS) 151 error = EINVAL; 152 else 153 V_tcp_v6mssdflt = new; 154 } 155 return (error); 156 } 157 158 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 159 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_v6mssdflt), 0, 160 &sysctl_net_inet_tcp_mss_v6_check, "I", 161 "Default TCP Maximum Segment Size for IPv6"); 162 #endif /* INET6 */ 163 164 /* 165 * Minimum MSS we accept and use. This prevents DoS attacks where 166 * we are forced to a ridiculous low MSS like 20 and send hundreds 167 * of packets instead of one. The effect scales with the available 168 * bandwidth and quickly saturates the CPU and network interface 169 * with packet generation and sending. Set to zero to disable MINMSS 170 * checking. This setting prevents us from sending too small packets. 171 */ 172 VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS; 173 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 174 &VNET_NAME(tcp_minmss), 0, 175 "Minmum TCP Maximum Segment Size"); 176 177 VNET_DEFINE(int, tcp_do_rfc1323) = 1; 178 SYSCTL_VNET_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 179 &VNET_NAME(tcp_do_rfc1323), 0, 180 "Enable rfc1323 (high performance TCP) extensions"); 181 182 static int tcp_log_debug = 0; 183 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW, 184 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments"); 185 186 static int tcp_tcbhashsize = 0; 187 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 188 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 189 190 static int do_tcpdrain = 1; 191 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 192 "Enable tcp_drain routine for extra help when low on mbufs"); 193 194 SYSCTL_VNET_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 195 &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs"); 196 197 static VNET_DEFINE(int, icmp_may_rst) = 1; 198 #define V_icmp_may_rst VNET(icmp_may_rst) 199 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, 200 &VNET_NAME(icmp_may_rst), 0, 201 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 202 203 static VNET_DEFINE(int, tcp_isn_reseed_interval) = 0; 204 #define V_tcp_isn_reseed_interval VNET(tcp_isn_reseed_interval) 205 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 206 &VNET_NAME(tcp_isn_reseed_interval), 0, 207 "Seconds between reseeding of ISN secret"); 208 209 static int tcp_soreceive_stream = 0; 210 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN, 211 &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets"); 212 213 #ifdef TCP_SIGNATURE 214 static int tcp_sig_checksigs = 1; 215 SYSCTL_INT(_net_inet_tcp, OID_AUTO, signature_verify_input, CTLFLAG_RW, 216 &tcp_sig_checksigs, 0, "Verify RFC2385 digests on inbound traffic"); 217 #endif 218 219 VNET_DEFINE(uma_zone_t, sack_hole_zone); 220 #define V_sack_hole_zone VNET(sack_hole_zone) 221 222 VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]); 223 224 static struct inpcb *tcp_notify(struct inpcb *, int); 225 static char * tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, 226 void *ip4hdr, const void *ip6hdr); 227 228 /* 229 * Target size of TCP PCB hash tables. Must be a power of two. 230 * 231 * Note that this can be overridden by the kernel environment 232 * variable net.inet.tcp.tcbhashsize 233 */ 234 #ifndef TCBHASHSIZE 235 #define TCBHASHSIZE 512 236 #endif 237 238 /* 239 * XXX 240 * Callouts should be moved into struct tcp directly. They are currently 241 * separate because the tcpcb structure is exported to userland for sysctl 242 * parsing purposes, which do not know about callouts. 243 */ 244 struct tcpcb_mem { 245 struct tcpcb tcb; 246 struct tcp_timer tt; 247 struct cc_var ccv; 248 struct osd osd; 249 }; 250 251 static VNET_DEFINE(uma_zone_t, tcpcb_zone); 252 #define V_tcpcb_zone VNET(tcpcb_zone) 253 254 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers"); 255 static struct mtx isn_mtx; 256 257 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 258 #define ISN_LOCK() mtx_lock(&isn_mtx) 259 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 260 261 /* 262 * TCP initialization. 263 */ 264 static void 265 tcp_zone_change(void *tag) 266 { 267 268 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 269 uma_zone_set_max(V_tcpcb_zone, maxsockets); 270 tcp_tw_zone_change(); 271 } 272 273 static int 274 tcp_inpcb_init(void *mem, int size, int flags) 275 { 276 struct inpcb *inp = mem; 277 278 INP_LOCK_INIT(inp, "inp", "tcpinp"); 279 return (0); 280 } 281 282 void 283 tcp_init(void) 284 { 285 int hashsize; 286 287 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN, 288 &V_tcp_hhh[HHOOK_TCP_EST_IN], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0) 289 printf("%s: WARNING: unable to register helper hook\n", __func__); 290 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT, 291 &V_tcp_hhh[HHOOK_TCP_EST_OUT], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0) 292 printf("%s: WARNING: unable to register helper hook\n", __func__); 293 294 hashsize = TCBHASHSIZE; 295 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 296 if (!powerof2(hashsize)) { 297 printf("WARNING: TCB hash size not a power of 2\n"); 298 hashsize = 512; /* safe default */ 299 } 300 in_pcbinfo_init(&V_tcbinfo, "tcp", &V_tcb, hashsize, hashsize, 301 "tcp_inpcb", tcp_inpcb_init, NULL, UMA_ZONE_NOFREE, 302 IPI_HASHFIELDS_4TUPLE); 303 304 /* 305 * These have to be type stable for the benefit of the timers. 306 */ 307 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 308 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 309 uma_zone_set_max(V_tcpcb_zone, maxsockets); 310 311 tcp_tw_init(); 312 syncache_init(); 313 tcp_hc_init(); 314 tcp_reass_init(); 315 316 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack); 317 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 318 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 319 320 /* Skip initialization of globals for non-default instances. */ 321 if (!IS_DEFAULT_VNET(curvnet)) 322 return; 323 324 /* XXX virtualize those bellow? */ 325 tcp_delacktime = TCPTV_DELACK; 326 tcp_keepinit = TCPTV_KEEP_INIT; 327 tcp_keepidle = TCPTV_KEEP_IDLE; 328 tcp_keepintvl = TCPTV_KEEPINTVL; 329 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 330 tcp_msl = TCPTV_MSL; 331 tcp_rexmit_min = TCPTV_MIN; 332 if (tcp_rexmit_min < 1) 333 tcp_rexmit_min = 1; 334 tcp_rexmit_slop = TCPTV_CPU_VAR; 335 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 336 tcp_tcbhashsize = hashsize; 337 338 TUNABLE_INT_FETCH("net.inet.tcp.soreceive_stream", &tcp_soreceive_stream); 339 if (tcp_soreceive_stream) { 340 #ifdef INET 341 tcp_usrreqs.pru_soreceive = soreceive_stream; 342 #endif 343 #ifdef INET6 344 tcp6_usrreqs.pru_soreceive = soreceive_stream; 345 #endif /* INET6 */ 346 } 347 348 #ifdef INET6 349 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 350 #else /* INET6 */ 351 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 352 #endif /* INET6 */ 353 if (max_protohdr < TCP_MINPROTOHDR) 354 max_protohdr = TCP_MINPROTOHDR; 355 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 356 panic("tcp_init"); 357 #undef TCP_MINPROTOHDR 358 359 ISN_LOCK_INIT(); 360 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 361 SHUTDOWN_PRI_DEFAULT); 362 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 363 EVENTHANDLER_PRI_ANY); 364 } 365 366 #ifdef VIMAGE 367 void 368 tcp_destroy(void) 369 { 370 371 tcp_reass_destroy(); 372 tcp_hc_destroy(); 373 syncache_destroy(); 374 tcp_tw_destroy(); 375 in_pcbinfo_destroy(&V_tcbinfo); 376 uma_zdestroy(V_sack_hole_zone); 377 uma_zdestroy(V_tcpcb_zone); 378 } 379 #endif 380 381 void 382 tcp_fini(void *xtp) 383 { 384 385 } 386 387 /* 388 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 389 * tcp_template used to store this data in mbufs, but we now recopy it out 390 * of the tcpcb each time to conserve mbufs. 391 */ 392 void 393 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 394 { 395 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 396 397 INP_WLOCK_ASSERT(inp); 398 399 #ifdef INET6 400 if ((inp->inp_vflag & INP_IPV6) != 0) { 401 struct ip6_hdr *ip6; 402 403 ip6 = (struct ip6_hdr *)ip_ptr; 404 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 405 (inp->inp_flow & IPV6_FLOWINFO_MASK); 406 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 407 (IPV6_VERSION & IPV6_VERSION_MASK); 408 ip6->ip6_nxt = IPPROTO_TCP; 409 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 410 ip6->ip6_src = inp->in6p_laddr; 411 ip6->ip6_dst = inp->in6p_faddr; 412 } 413 #endif /* INET6 */ 414 #if defined(INET6) && defined(INET) 415 else 416 #endif 417 #ifdef INET 418 { 419 struct ip *ip; 420 421 ip = (struct ip *)ip_ptr; 422 ip->ip_v = IPVERSION; 423 ip->ip_hl = 5; 424 ip->ip_tos = inp->inp_ip_tos; 425 ip->ip_len = 0; 426 ip->ip_id = 0; 427 ip->ip_off = 0; 428 ip->ip_ttl = inp->inp_ip_ttl; 429 ip->ip_sum = 0; 430 ip->ip_p = IPPROTO_TCP; 431 ip->ip_src = inp->inp_laddr; 432 ip->ip_dst = inp->inp_faddr; 433 } 434 #endif /* INET */ 435 th->th_sport = inp->inp_lport; 436 th->th_dport = inp->inp_fport; 437 th->th_seq = 0; 438 th->th_ack = 0; 439 th->th_x2 = 0; 440 th->th_off = 5; 441 th->th_flags = 0; 442 th->th_win = 0; 443 th->th_urp = 0; 444 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 445 } 446 447 /* 448 * Create template to be used to send tcp packets on a connection. 449 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 450 * use for this function is in keepalives, which use tcp_respond. 451 */ 452 struct tcptemp * 453 tcpip_maketemplate(struct inpcb *inp) 454 { 455 struct tcptemp *t; 456 457 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT); 458 if (t == NULL) 459 return (NULL); 460 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t); 461 return (t); 462 } 463 464 /* 465 * Send a single message to the TCP at address specified by 466 * the given TCP/IP header. If m == NULL, then we make a copy 467 * of the tcpiphdr at ti and send directly to the addressed host. 468 * This is used to force keep alive messages out using the TCP 469 * template for a connection. If flags are given then we send 470 * a message back to the TCP which originated the * segment ti, 471 * and discard the mbuf containing it and any other attached mbufs. 472 * 473 * In any case the ack and sequence number of the transmitted 474 * segment are as specified by the parameters. 475 * 476 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 477 */ 478 void 479 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 480 tcp_seq ack, tcp_seq seq, int flags) 481 { 482 int tlen; 483 int win = 0; 484 struct ip *ip; 485 struct tcphdr *nth; 486 #ifdef INET6 487 struct ip6_hdr *ip6; 488 int isipv6; 489 #endif /* INET6 */ 490 int ipflags = 0; 491 struct inpcb *inp; 492 493 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 494 495 #ifdef INET6 496 isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4); 497 ip6 = ipgen; 498 #endif /* INET6 */ 499 ip = ipgen; 500 501 if (tp != NULL) { 502 inp = tp->t_inpcb; 503 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 504 INP_WLOCK_ASSERT(inp); 505 } else 506 inp = NULL; 507 508 if (tp != NULL) { 509 if (!(flags & TH_RST)) { 510 win = sbspace(&inp->inp_socket->so_rcv); 511 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 512 win = (long)TCP_MAXWIN << tp->rcv_scale; 513 } 514 } 515 if (m == NULL) { 516 m = m_gethdr(M_DONTWAIT, MT_DATA); 517 if (m == NULL) 518 return; 519 tlen = 0; 520 m->m_data += max_linkhdr; 521 #ifdef INET6 522 if (isipv6) { 523 bcopy((caddr_t)ip6, mtod(m, caddr_t), 524 sizeof(struct ip6_hdr)); 525 ip6 = mtod(m, struct ip6_hdr *); 526 nth = (struct tcphdr *)(ip6 + 1); 527 } else 528 #endif /* INET6 */ 529 { 530 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 531 ip = mtod(m, struct ip *); 532 nth = (struct tcphdr *)(ip + 1); 533 } 534 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 535 flags = TH_ACK; 536 } else { 537 /* 538 * reuse the mbuf. 539 * XXX MRT We inherrit the FIB, which is lucky. 540 */ 541 m_freem(m->m_next); 542 m->m_next = NULL; 543 m->m_data = (caddr_t)ipgen; 544 m_addr_changed(m); 545 /* m_len is set later */ 546 tlen = 0; 547 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 548 #ifdef INET6 549 if (isipv6) { 550 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 551 nth = (struct tcphdr *)(ip6 + 1); 552 } else 553 #endif /* INET6 */ 554 { 555 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t); 556 nth = (struct tcphdr *)(ip + 1); 557 } 558 if (th != nth) { 559 /* 560 * this is usually a case when an extension header 561 * exists between the IPv6 header and the 562 * TCP header. 563 */ 564 nth->th_sport = th->th_sport; 565 nth->th_dport = th->th_dport; 566 } 567 xchg(nth->th_dport, nth->th_sport, uint16_t); 568 #undef xchg 569 } 570 #ifdef INET6 571 if (isipv6) { 572 ip6->ip6_flow = 0; 573 ip6->ip6_vfc = IPV6_VERSION; 574 ip6->ip6_nxt = IPPROTO_TCP; 575 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 576 tlen)); 577 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 578 } 579 #endif 580 #if defined(INET) && defined(INET6) 581 else 582 #endif 583 #ifdef INET 584 { 585 tlen += sizeof (struct tcpiphdr); 586 ip->ip_len = tlen; 587 ip->ip_ttl = V_ip_defttl; 588 if (V_path_mtu_discovery) 589 ip->ip_off |= IP_DF; 590 } 591 #endif 592 m->m_len = tlen; 593 m->m_pkthdr.len = tlen; 594 m->m_pkthdr.rcvif = NULL; 595 #ifdef MAC 596 if (inp != NULL) { 597 /* 598 * Packet is associated with a socket, so allow the 599 * label of the response to reflect the socket label. 600 */ 601 INP_WLOCK_ASSERT(inp); 602 mac_inpcb_create_mbuf(inp, m); 603 } else { 604 /* 605 * Packet is not associated with a socket, so possibly 606 * update the label in place. 607 */ 608 mac_netinet_tcp_reply(m); 609 } 610 #endif 611 nth->th_seq = htonl(seq); 612 nth->th_ack = htonl(ack); 613 nth->th_x2 = 0; 614 nth->th_off = sizeof (struct tcphdr) >> 2; 615 nth->th_flags = flags; 616 if (tp != NULL) 617 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 618 else 619 nth->th_win = htons((u_short)win); 620 nth->th_urp = 0; 621 #ifdef INET6 622 if (isipv6) { 623 nth->th_sum = 0; 624 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 625 sizeof(struct ip6_hdr), 626 tlen - sizeof(struct ip6_hdr)); 627 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 628 NULL, NULL); 629 } 630 #endif /* INET6 */ 631 #if defined(INET6) && defined(INET) 632 else 633 #endif 634 #ifdef INET 635 { 636 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 637 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 638 m->m_pkthdr.csum_flags = CSUM_TCP; 639 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 640 } 641 #endif /* INET */ 642 #ifdef TCPDEBUG 643 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 644 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 645 #endif 646 #ifdef INET6 647 if (isipv6) 648 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 649 #endif /* INET6 */ 650 #if defined(INET) && defined(INET6) 651 else 652 #endif 653 #ifdef INET 654 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 655 #endif 656 } 657 658 /* 659 * Create a new TCP control block, making an 660 * empty reassembly queue and hooking it to the argument 661 * protocol control block. The `inp' parameter must have 662 * come from the zone allocator set up in tcp_init(). 663 */ 664 struct tcpcb * 665 tcp_newtcpcb(struct inpcb *inp) 666 { 667 struct tcpcb_mem *tm; 668 struct tcpcb *tp; 669 #ifdef INET6 670 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 671 #endif /* INET6 */ 672 673 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO); 674 if (tm == NULL) 675 return (NULL); 676 tp = &tm->tcb; 677 678 /* Initialise cc_var struct for this tcpcb. */ 679 tp->ccv = &tm->ccv; 680 tp->ccv->type = IPPROTO_TCP; 681 tp->ccv->ccvc.tcp = tp; 682 683 /* 684 * Use the current system default CC algorithm. 685 */ 686 CC_LIST_RLOCK(); 687 KASSERT(!STAILQ_EMPTY(&cc_list), ("cc_list is empty!")); 688 CC_ALGO(tp) = CC_DEFAULT(); 689 CC_LIST_RUNLOCK(); 690 691 if (CC_ALGO(tp)->cb_init != NULL) 692 if (CC_ALGO(tp)->cb_init(tp->ccv) > 0) { 693 uma_zfree(V_tcpcb_zone, tm); 694 return (NULL); 695 } 696 697 tp->osd = &tm->osd; 698 if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) { 699 uma_zfree(V_tcpcb_zone, tm); 700 return (NULL); 701 } 702 703 #ifdef VIMAGE 704 tp->t_vnet = inp->inp_vnet; 705 #endif 706 tp->t_timers = &tm->tt; 707 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 708 tp->t_maxseg = tp->t_maxopd = 709 #ifdef INET6 710 isipv6 ? V_tcp_v6mssdflt : 711 #endif /* INET6 */ 712 V_tcp_mssdflt; 713 714 /* Set up our timeouts. */ 715 callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE); 716 callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE); 717 callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE); 718 callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE); 719 callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE); 720 721 if (V_tcp_do_rfc1323) 722 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 723 if (V_tcp_do_sack) 724 tp->t_flags |= TF_SACK_PERMIT; 725 TAILQ_INIT(&tp->snd_holes); 726 tp->t_inpcb = inp; /* XXX */ 727 /* 728 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 729 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 730 * reasonable initial retransmit time. 731 */ 732 tp->t_srtt = TCPTV_SRTTBASE; 733 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 734 tp->t_rttmin = tcp_rexmit_min; 735 tp->t_rxtcur = TCPTV_RTOBASE; 736 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 737 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 738 tp->t_rcvtime = ticks; 739 /* 740 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 741 * because the socket may be bound to an IPv6 wildcard address, 742 * which may match an IPv4-mapped IPv6 address. 743 */ 744 inp->inp_ip_ttl = V_ip_defttl; 745 inp->inp_ppcb = tp; 746 return (tp); /* XXX */ 747 } 748 749 /* 750 * Switch the congestion control algorithm back to NewReno for any active 751 * control blocks using an algorithm which is about to go away. 752 * This ensures the CC framework can allow the unload to proceed without leaving 753 * any dangling pointers which would trigger a panic. 754 * Returning non-zero would inform the CC framework that something went wrong 755 * and it would be unsafe to allow the unload to proceed. However, there is no 756 * way for this to occur with this implementation so we always return zero. 757 */ 758 int 759 tcp_ccalgounload(struct cc_algo *unload_algo) 760 { 761 struct cc_algo *tmpalgo; 762 struct inpcb *inp; 763 struct tcpcb *tp; 764 VNET_ITERATOR_DECL(vnet_iter); 765 766 /* 767 * Check all active control blocks across all network stacks and change 768 * any that are using "unload_algo" back to NewReno. If "unload_algo" 769 * requires cleanup code to be run, call it. 770 */ 771 VNET_LIST_RLOCK(); 772 VNET_FOREACH(vnet_iter) { 773 CURVNET_SET(vnet_iter); 774 INP_INFO_RLOCK(&V_tcbinfo); 775 /* 776 * New connections already part way through being initialised 777 * with the CC algo we're removing will not race with this code 778 * because the INP_INFO_WLOCK is held during initialisation. We 779 * therefore don't enter the loop below until the connection 780 * list has stabilised. 781 */ 782 LIST_FOREACH(inp, &V_tcb, inp_list) { 783 INP_WLOCK(inp); 784 /* Important to skip tcptw structs. */ 785 if (!(inp->inp_flags & INP_TIMEWAIT) && 786 (tp = intotcpcb(inp)) != NULL) { 787 /* 788 * By holding INP_WLOCK here, we are assured 789 * that the connection is not currently 790 * executing inside the CC module's functions 791 * i.e. it is safe to make the switch back to 792 * NewReno. 793 */ 794 if (CC_ALGO(tp) == unload_algo) { 795 tmpalgo = CC_ALGO(tp); 796 /* NewReno does not require any init. */ 797 CC_ALGO(tp) = &newreno_cc_algo; 798 if (tmpalgo->cb_destroy != NULL) 799 tmpalgo->cb_destroy(tp->ccv); 800 } 801 } 802 INP_WUNLOCK(inp); 803 } 804 INP_INFO_RUNLOCK(&V_tcbinfo); 805 CURVNET_RESTORE(); 806 } 807 VNET_LIST_RUNLOCK(); 808 809 return (0); 810 } 811 812 /* 813 * Drop a TCP connection, reporting 814 * the specified error. If connection is synchronized, 815 * then send a RST to peer. 816 */ 817 struct tcpcb * 818 tcp_drop(struct tcpcb *tp, int errno) 819 { 820 struct socket *so = tp->t_inpcb->inp_socket; 821 822 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 823 INP_WLOCK_ASSERT(tp->t_inpcb); 824 825 if (TCPS_HAVERCVDSYN(tp->t_state)) { 826 tp->t_state = TCPS_CLOSED; 827 (void) tcp_output_reset(tp); 828 TCPSTAT_INC(tcps_drops); 829 } else 830 TCPSTAT_INC(tcps_conndrops); 831 if (errno == ETIMEDOUT && tp->t_softerror) 832 errno = tp->t_softerror; 833 so->so_error = errno; 834 return (tcp_close(tp)); 835 } 836 837 void 838 tcp_discardcb(struct tcpcb *tp) 839 { 840 struct inpcb *inp = tp->t_inpcb; 841 struct socket *so = inp->inp_socket; 842 #ifdef INET6 843 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 844 #endif /* INET6 */ 845 846 INP_WLOCK_ASSERT(inp); 847 848 /* 849 * Make sure that all of our timers are stopped before we delete the 850 * PCB. 851 * 852 * XXXRW: Really, we would like to use callout_drain() here in order 853 * to avoid races experienced in tcp_timer.c where a timer is already 854 * executing at this point. However, we can't, both because we're 855 * running in a context where we can't sleep, and also because we 856 * hold locks required by the timers. What we instead need to do is 857 * test to see if callout_drain() is required, and if so, defer some 858 * portion of the remainder of tcp_discardcb() to an asynchronous 859 * context that can callout_drain() and then continue. Some care 860 * will be required to ensure that no further processing takes place 861 * on the tcpcb, even though it hasn't been freed (a flag?). 862 */ 863 callout_stop(&tp->t_timers->tt_rexmt); 864 callout_stop(&tp->t_timers->tt_persist); 865 callout_stop(&tp->t_timers->tt_keep); 866 callout_stop(&tp->t_timers->tt_2msl); 867 callout_stop(&tp->t_timers->tt_delack); 868 869 /* 870 * If we got enough samples through the srtt filter, 871 * save the rtt and rttvar in the routing entry. 872 * 'Enough' is arbitrarily defined as 4 rtt samples. 873 * 4 samples is enough for the srtt filter to converge 874 * to within enough % of the correct value; fewer samples 875 * and we could save a bogus rtt. The danger is not high 876 * as tcp quickly recovers from everything. 877 * XXX: Works very well but needs some more statistics! 878 */ 879 if (tp->t_rttupdated >= 4) { 880 struct hc_metrics_lite metrics; 881 u_long ssthresh; 882 883 bzero(&metrics, sizeof(metrics)); 884 /* 885 * Update the ssthresh always when the conditions below 886 * are satisfied. This gives us better new start value 887 * for the congestion avoidance for new connections. 888 * ssthresh is only set if packet loss occured on a session. 889 * 890 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 891 * being torn down. Ideally this code would not use 'so'. 892 */ 893 ssthresh = tp->snd_ssthresh; 894 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 895 /* 896 * convert the limit from user data bytes to 897 * packets then to packet data bytes. 898 */ 899 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 900 if (ssthresh < 2) 901 ssthresh = 2; 902 ssthresh *= (u_long)(tp->t_maxseg + 903 #ifdef INET6 904 (isipv6 ? sizeof (struct ip6_hdr) + 905 sizeof (struct tcphdr) : 906 #endif 907 sizeof (struct tcpiphdr) 908 #ifdef INET6 909 ) 910 #endif 911 ); 912 } else 913 ssthresh = 0; 914 metrics.rmx_ssthresh = ssthresh; 915 916 metrics.rmx_rtt = tp->t_srtt; 917 metrics.rmx_rttvar = tp->t_rttvar; 918 metrics.rmx_cwnd = tp->snd_cwnd; 919 metrics.rmx_sendpipe = 0; 920 metrics.rmx_recvpipe = 0; 921 922 tcp_hc_update(&inp->inp_inc, &metrics); 923 } 924 925 /* free the reassembly queue, if any */ 926 tcp_reass_flush(tp); 927 /* Disconnect offload device, if any. */ 928 tcp_offload_detach(tp); 929 930 tcp_free_sackholes(tp); 931 932 /* Allow the CC algorithm to clean up after itself. */ 933 if (CC_ALGO(tp)->cb_destroy != NULL) 934 CC_ALGO(tp)->cb_destroy(tp->ccv); 935 936 khelp_destroy_osd(tp->osd); 937 938 CC_ALGO(tp) = NULL; 939 inp->inp_ppcb = NULL; 940 tp->t_inpcb = NULL; 941 uma_zfree(V_tcpcb_zone, tp); 942 } 943 944 /* 945 * Attempt to close a TCP control block, marking it as dropped, and freeing 946 * the socket if we hold the only reference. 947 */ 948 struct tcpcb * 949 tcp_close(struct tcpcb *tp) 950 { 951 struct inpcb *inp = tp->t_inpcb; 952 struct socket *so; 953 954 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 955 INP_WLOCK_ASSERT(inp); 956 957 /* Notify any offload devices of listener close */ 958 if (tp->t_state == TCPS_LISTEN) 959 tcp_offload_listen_close(tp); 960 in_pcbdrop(inp); 961 TCPSTAT_INC(tcps_closed); 962 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 963 so = inp->inp_socket; 964 soisdisconnected(so); 965 if (inp->inp_flags & INP_SOCKREF) { 966 KASSERT(so->so_state & SS_PROTOREF, 967 ("tcp_close: !SS_PROTOREF")); 968 inp->inp_flags &= ~INP_SOCKREF; 969 INP_WUNLOCK(inp); 970 ACCEPT_LOCK(); 971 SOCK_LOCK(so); 972 so->so_state &= ~SS_PROTOREF; 973 sofree(so); 974 return (NULL); 975 } 976 return (tp); 977 } 978 979 void 980 tcp_drain(void) 981 { 982 VNET_ITERATOR_DECL(vnet_iter); 983 984 if (!do_tcpdrain) 985 return; 986 987 VNET_LIST_RLOCK_NOSLEEP(); 988 VNET_FOREACH(vnet_iter) { 989 CURVNET_SET(vnet_iter); 990 struct inpcb *inpb; 991 struct tcpcb *tcpb; 992 993 /* 994 * Walk the tcpbs, if existing, and flush the reassembly queue, 995 * if there is one... 996 * XXX: The "Net/3" implementation doesn't imply that the TCP 997 * reassembly queue should be flushed, but in a situation 998 * where we're really low on mbufs, this is potentially 999 * usefull. 1000 */ 1001 INP_INFO_RLOCK(&V_tcbinfo); 1002 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) { 1003 if (inpb->inp_flags & INP_TIMEWAIT) 1004 continue; 1005 INP_WLOCK(inpb); 1006 if ((tcpb = intotcpcb(inpb)) != NULL) { 1007 tcp_reass_flush(tcpb); 1008 tcp_clean_sackreport(tcpb); 1009 } 1010 INP_WUNLOCK(inpb); 1011 } 1012 INP_INFO_RUNLOCK(&V_tcbinfo); 1013 CURVNET_RESTORE(); 1014 } 1015 VNET_LIST_RUNLOCK_NOSLEEP(); 1016 } 1017 1018 /* 1019 * Notify a tcp user of an asynchronous error; 1020 * store error as soft error, but wake up user 1021 * (for now, won't do anything until can select for soft error). 1022 * 1023 * Do not wake up user since there currently is no mechanism for 1024 * reporting soft errors (yet - a kqueue filter may be added). 1025 */ 1026 static struct inpcb * 1027 tcp_notify(struct inpcb *inp, int error) 1028 { 1029 struct tcpcb *tp; 1030 1031 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 1032 INP_WLOCK_ASSERT(inp); 1033 1034 if ((inp->inp_flags & INP_TIMEWAIT) || 1035 (inp->inp_flags & INP_DROPPED)) 1036 return (inp); 1037 1038 tp = intotcpcb(inp); 1039 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 1040 1041 /* 1042 * Ignore some errors if we are hooked up. 1043 * If connection hasn't completed, has retransmitted several times, 1044 * and receives a second error, give up now. This is better 1045 * than waiting a long time to establish a connection that 1046 * can never complete. 1047 */ 1048 if (tp->t_state == TCPS_ESTABLISHED && 1049 (error == EHOSTUNREACH || error == ENETUNREACH || 1050 error == EHOSTDOWN)) { 1051 return (inp); 1052 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1053 tp->t_softerror) { 1054 tp = tcp_drop(tp, error); 1055 if (tp != NULL) 1056 return (inp); 1057 else 1058 return (NULL); 1059 } else { 1060 tp->t_softerror = error; 1061 return (inp); 1062 } 1063 #if 0 1064 wakeup( &so->so_timeo); 1065 sorwakeup(so); 1066 sowwakeup(so); 1067 #endif 1068 } 1069 1070 static int 1071 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1072 { 1073 int error, i, m, n, pcb_count; 1074 struct inpcb *inp, **inp_list; 1075 inp_gen_t gencnt; 1076 struct xinpgen xig; 1077 1078 /* 1079 * The process of preparing the TCB list is too time-consuming and 1080 * resource-intensive to repeat twice on every request. 1081 */ 1082 if (req->oldptr == NULL) { 1083 n = V_tcbinfo.ipi_count + syncache_pcbcount(); 1084 n += imax(n / 8, 10); 1085 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb); 1086 return (0); 1087 } 1088 1089 if (req->newptr != NULL) 1090 return (EPERM); 1091 1092 /* 1093 * OK, now we're committed to doing something. 1094 */ 1095 INP_INFO_RLOCK(&V_tcbinfo); 1096 gencnt = V_tcbinfo.ipi_gencnt; 1097 n = V_tcbinfo.ipi_count; 1098 INP_INFO_RUNLOCK(&V_tcbinfo); 1099 1100 m = syncache_pcbcount(); 1101 1102 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 1103 + (n + m) * sizeof(struct xtcpcb)); 1104 if (error != 0) 1105 return (error); 1106 1107 xig.xig_len = sizeof xig; 1108 xig.xig_count = n + m; 1109 xig.xig_gen = gencnt; 1110 xig.xig_sogen = so_gencnt; 1111 error = SYSCTL_OUT(req, &xig, sizeof xig); 1112 if (error) 1113 return (error); 1114 1115 error = syncache_pcblist(req, m, &pcb_count); 1116 if (error) 1117 return (error); 1118 1119 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 1120 if (inp_list == NULL) 1121 return (ENOMEM); 1122 1123 INP_INFO_RLOCK(&V_tcbinfo); 1124 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0; 1125 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) { 1126 INP_WLOCK(inp); 1127 if (inp->inp_gencnt <= gencnt) { 1128 /* 1129 * XXX: This use of cr_cansee(), introduced with 1130 * TCP state changes, is not quite right, but for 1131 * now, better than nothing. 1132 */ 1133 if (inp->inp_flags & INP_TIMEWAIT) { 1134 if (intotw(inp) != NULL) 1135 error = cr_cansee(req->td->td_ucred, 1136 intotw(inp)->tw_cred); 1137 else 1138 error = EINVAL; /* Skip this inp. */ 1139 } else 1140 error = cr_canseeinpcb(req->td->td_ucred, inp); 1141 if (error == 0) { 1142 in_pcbref(inp); 1143 inp_list[i++] = inp; 1144 } 1145 } 1146 INP_WUNLOCK(inp); 1147 } 1148 INP_INFO_RUNLOCK(&V_tcbinfo); 1149 n = i; 1150 1151 error = 0; 1152 for (i = 0; i < n; i++) { 1153 inp = inp_list[i]; 1154 INP_RLOCK(inp); 1155 if (inp->inp_gencnt <= gencnt) { 1156 struct xtcpcb xt; 1157 void *inp_ppcb; 1158 1159 bzero(&xt, sizeof(xt)); 1160 xt.xt_len = sizeof xt; 1161 /* XXX should avoid extra copy */ 1162 bcopy(inp, &xt.xt_inp, sizeof *inp); 1163 inp_ppcb = inp->inp_ppcb; 1164 if (inp_ppcb == NULL) 1165 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1166 else if (inp->inp_flags & INP_TIMEWAIT) { 1167 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1168 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1169 } else { 1170 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1171 if (xt.xt_tp.t_timers) 1172 tcp_timer_to_xtimer(&xt.xt_tp, xt.xt_tp.t_timers, &xt.xt_timer); 1173 } 1174 if (inp->inp_socket != NULL) 1175 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1176 else { 1177 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1178 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1179 } 1180 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1181 INP_RUNLOCK(inp); 1182 error = SYSCTL_OUT(req, &xt, sizeof xt); 1183 } else 1184 INP_RUNLOCK(inp); 1185 } 1186 INP_INFO_WLOCK(&V_tcbinfo); 1187 for (i = 0; i < n; i++) { 1188 inp = inp_list[i]; 1189 INP_RLOCK(inp); 1190 if (!in_pcbrele_rlocked(inp)) 1191 INP_RUNLOCK(inp); 1192 } 1193 INP_INFO_WUNLOCK(&V_tcbinfo); 1194 1195 if (!error) { 1196 /* 1197 * Give the user an updated idea of our state. 1198 * If the generation differs from what we told 1199 * her before, she knows that something happened 1200 * while we were processing this request, and it 1201 * might be necessary to retry. 1202 */ 1203 INP_INFO_RLOCK(&V_tcbinfo); 1204 xig.xig_gen = V_tcbinfo.ipi_gencnt; 1205 xig.xig_sogen = so_gencnt; 1206 xig.xig_count = V_tcbinfo.ipi_count + pcb_count; 1207 INP_INFO_RUNLOCK(&V_tcbinfo); 1208 error = SYSCTL_OUT(req, &xig, sizeof xig); 1209 } 1210 free(inp_list, M_TEMP); 1211 return (error); 1212 } 1213 1214 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, 1215 CTLTYPE_OPAQUE | CTLFLAG_RD, NULL, 0, 1216 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1217 1218 #ifdef INET 1219 static int 1220 tcp_getcred(SYSCTL_HANDLER_ARGS) 1221 { 1222 struct xucred xuc; 1223 struct sockaddr_in addrs[2]; 1224 struct inpcb *inp; 1225 int error; 1226 1227 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1228 if (error) 1229 return (error); 1230 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1231 if (error) 1232 return (error); 1233 inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 1234 addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL); 1235 if (inp != NULL) { 1236 if (inp->inp_socket == NULL) 1237 error = ENOENT; 1238 if (error == 0) 1239 error = cr_canseeinpcb(req->td->td_ucred, inp); 1240 if (error == 0) 1241 cru2x(inp->inp_cred, &xuc); 1242 INP_RUNLOCK(inp); 1243 } else 1244 error = ENOENT; 1245 if (error == 0) 1246 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1247 return (error); 1248 } 1249 1250 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1251 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1252 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1253 #endif /* INET */ 1254 1255 #ifdef INET6 1256 static int 1257 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1258 { 1259 struct xucred xuc; 1260 struct sockaddr_in6 addrs[2]; 1261 struct inpcb *inp; 1262 int error; 1263 #ifdef INET 1264 int mapped = 0; 1265 #endif 1266 1267 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1268 if (error) 1269 return (error); 1270 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1271 if (error) 1272 return (error); 1273 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 || 1274 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) { 1275 return (error); 1276 } 1277 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1278 #ifdef INET 1279 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1280 mapped = 1; 1281 else 1282 #endif 1283 return (EINVAL); 1284 } 1285 1286 #ifdef INET 1287 if (mapped == 1) 1288 inp = in_pcblookup(&V_tcbinfo, 1289 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1290 addrs[1].sin6_port, 1291 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1292 addrs[0].sin6_port, INPLOOKUP_RLOCKPCB, NULL); 1293 else 1294 #endif 1295 inp = in6_pcblookup(&V_tcbinfo, 1296 &addrs[1].sin6_addr, addrs[1].sin6_port, 1297 &addrs[0].sin6_addr, addrs[0].sin6_port, 1298 INPLOOKUP_RLOCKPCB, NULL); 1299 if (inp != NULL) { 1300 if (inp->inp_socket == NULL) 1301 error = ENOENT; 1302 if (error == 0) 1303 error = cr_canseeinpcb(req->td->td_ucred, inp); 1304 if (error == 0) 1305 cru2x(inp->inp_cred, &xuc); 1306 INP_RUNLOCK(inp); 1307 } else 1308 error = ENOENT; 1309 if (error == 0) 1310 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1311 return (error); 1312 } 1313 1314 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1315 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1316 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1317 #endif /* INET6 */ 1318 1319 1320 #ifdef INET 1321 void 1322 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1323 { 1324 struct ip *ip = vip; 1325 struct tcphdr *th; 1326 struct in_addr faddr; 1327 struct inpcb *inp; 1328 struct tcpcb *tp; 1329 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1330 struct icmp *icp; 1331 struct in_conninfo inc; 1332 tcp_seq icmp_tcp_seq; 1333 int mtu; 1334 1335 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1336 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1337 return; 1338 1339 if (cmd == PRC_MSGSIZE) 1340 notify = tcp_mtudisc; 1341 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1342 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1343 notify = tcp_drop_syn_sent; 1344 /* 1345 * Redirects don't need to be handled up here. 1346 */ 1347 else if (PRC_IS_REDIRECT(cmd)) 1348 return; 1349 /* 1350 * Source quench is depreciated. 1351 */ 1352 else if (cmd == PRC_QUENCH) 1353 return; 1354 /* 1355 * Hostdead is ugly because it goes linearly through all PCBs. 1356 * XXX: We never get this from ICMP, otherwise it makes an 1357 * excellent DoS attack on machines with many connections. 1358 */ 1359 else if (cmd == PRC_HOSTDEAD) 1360 ip = NULL; 1361 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1362 return; 1363 if (ip != NULL) { 1364 icp = (struct icmp *)((caddr_t)ip 1365 - offsetof(struct icmp, icmp_ip)); 1366 th = (struct tcphdr *)((caddr_t)ip 1367 + (ip->ip_hl << 2)); 1368 INP_INFO_WLOCK(&V_tcbinfo); 1369 inp = in_pcblookup(&V_tcbinfo, faddr, th->th_dport, 1370 ip->ip_src, th->th_sport, INPLOOKUP_WLOCKPCB, NULL); 1371 if (inp != NULL) { 1372 if (!(inp->inp_flags & INP_TIMEWAIT) && 1373 !(inp->inp_flags & INP_DROPPED) && 1374 !(inp->inp_socket == NULL)) { 1375 icmp_tcp_seq = htonl(th->th_seq); 1376 tp = intotcpcb(inp); 1377 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1378 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1379 if (cmd == PRC_MSGSIZE) { 1380 /* 1381 * MTU discovery: 1382 * If we got a needfrag set the MTU 1383 * in the route to the suggested new 1384 * value (if given) and then notify. 1385 */ 1386 bzero(&inc, sizeof(inc)); 1387 inc.inc_faddr = faddr; 1388 inc.inc_fibnum = 1389 inp->inp_inc.inc_fibnum; 1390 1391 mtu = ntohs(icp->icmp_nextmtu); 1392 /* 1393 * If no alternative MTU was 1394 * proposed, try the next smaller 1395 * one. ip->ip_len has already 1396 * been swapped in icmp_input(). 1397 */ 1398 if (!mtu) 1399 mtu = ip_next_mtu(ip->ip_len, 1400 1); 1401 if (mtu < V_tcp_minmss 1402 + sizeof(struct tcpiphdr)) 1403 mtu = V_tcp_minmss 1404 + sizeof(struct tcpiphdr); 1405 /* 1406 * Only cache the MTU if it 1407 * is smaller than the interface 1408 * or route MTU. tcp_mtudisc() 1409 * will do right thing by itself. 1410 */ 1411 if (mtu <= tcp_maxmtu(&inc, NULL)) 1412 tcp_hc_updatemtu(&inc, mtu); 1413 } 1414 1415 inp = (*notify)(inp, inetctlerrmap[cmd]); 1416 } 1417 } 1418 if (inp != NULL) 1419 INP_WUNLOCK(inp); 1420 } else { 1421 bzero(&inc, sizeof(inc)); 1422 inc.inc_fport = th->th_dport; 1423 inc.inc_lport = th->th_sport; 1424 inc.inc_faddr = faddr; 1425 inc.inc_laddr = ip->ip_src; 1426 syncache_unreach(&inc, th); 1427 } 1428 INP_INFO_WUNLOCK(&V_tcbinfo); 1429 } else 1430 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify); 1431 } 1432 #endif /* INET */ 1433 1434 #ifdef INET6 1435 void 1436 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1437 { 1438 struct tcphdr th; 1439 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1440 struct ip6_hdr *ip6; 1441 struct mbuf *m; 1442 struct ip6ctlparam *ip6cp = NULL; 1443 const struct sockaddr_in6 *sa6_src = NULL; 1444 int off; 1445 struct tcp_portonly { 1446 u_int16_t th_sport; 1447 u_int16_t th_dport; 1448 } *thp; 1449 1450 if (sa->sa_family != AF_INET6 || 1451 sa->sa_len != sizeof(struct sockaddr_in6)) 1452 return; 1453 1454 if (cmd == PRC_MSGSIZE) 1455 notify = tcp_mtudisc; 1456 else if (!PRC_IS_REDIRECT(cmd) && 1457 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1458 return; 1459 /* Source quench is depreciated. */ 1460 else if (cmd == PRC_QUENCH) 1461 return; 1462 1463 /* if the parameter is from icmp6, decode it. */ 1464 if (d != NULL) { 1465 ip6cp = (struct ip6ctlparam *)d; 1466 m = ip6cp->ip6c_m; 1467 ip6 = ip6cp->ip6c_ip6; 1468 off = ip6cp->ip6c_off; 1469 sa6_src = ip6cp->ip6c_src; 1470 } else { 1471 m = NULL; 1472 ip6 = NULL; 1473 off = 0; /* fool gcc */ 1474 sa6_src = &sa6_any; 1475 } 1476 1477 if (ip6 != NULL) { 1478 struct in_conninfo inc; 1479 /* 1480 * XXX: We assume that when IPV6 is non NULL, 1481 * M and OFF are valid. 1482 */ 1483 1484 /* check if we can safely examine src and dst ports */ 1485 if (m->m_pkthdr.len < off + sizeof(*thp)) 1486 return; 1487 1488 bzero(&th, sizeof(th)); 1489 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1490 1491 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport, 1492 (struct sockaddr *)ip6cp->ip6c_src, 1493 th.th_sport, cmd, NULL, notify); 1494 1495 bzero(&inc, sizeof(inc)); 1496 inc.inc_fport = th.th_dport; 1497 inc.inc_lport = th.th_sport; 1498 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1499 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1500 inc.inc_flags |= INC_ISIPV6; 1501 INP_INFO_WLOCK(&V_tcbinfo); 1502 syncache_unreach(&inc, &th); 1503 INP_INFO_WUNLOCK(&V_tcbinfo); 1504 } else 1505 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1506 0, cmd, NULL, notify); 1507 } 1508 #endif /* INET6 */ 1509 1510 1511 /* 1512 * Following is where TCP initial sequence number generation occurs. 1513 * 1514 * There are two places where we must use initial sequence numbers: 1515 * 1. In SYN-ACK packets. 1516 * 2. In SYN packets. 1517 * 1518 * All ISNs for SYN-ACK packets are generated by the syncache. See 1519 * tcp_syncache.c for details. 1520 * 1521 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1522 * depends on this property. In addition, these ISNs should be 1523 * unguessable so as to prevent connection hijacking. To satisfy 1524 * the requirements of this situation, the algorithm outlined in 1525 * RFC 1948 is used, with only small modifications. 1526 * 1527 * Implementation details: 1528 * 1529 * Time is based off the system timer, and is corrected so that it 1530 * increases by one megabyte per second. This allows for proper 1531 * recycling on high speed LANs while still leaving over an hour 1532 * before rollover. 1533 * 1534 * As reading the *exact* system time is too expensive to be done 1535 * whenever setting up a TCP connection, we increment the time 1536 * offset in two ways. First, a small random positive increment 1537 * is added to isn_offset for each connection that is set up. 1538 * Second, the function tcp_isn_tick fires once per clock tick 1539 * and increments isn_offset as necessary so that sequence numbers 1540 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1541 * random positive increments serve only to ensure that the same 1542 * exact sequence number is never sent out twice (as could otherwise 1543 * happen when a port is recycled in less than the system tick 1544 * interval.) 1545 * 1546 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1547 * between seeding of isn_secret. This is normally set to zero, 1548 * as reseeding should not be necessary. 1549 * 1550 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1551 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1552 * general, this means holding an exclusive (write) lock. 1553 */ 1554 1555 #define ISN_BYTES_PER_SECOND 1048576 1556 #define ISN_STATIC_INCREMENT 4096 1557 #define ISN_RANDOM_INCREMENT (4096 - 1) 1558 1559 static VNET_DEFINE(u_char, isn_secret[32]); 1560 static VNET_DEFINE(int, isn_last); 1561 static VNET_DEFINE(int, isn_last_reseed); 1562 static VNET_DEFINE(u_int32_t, isn_offset); 1563 static VNET_DEFINE(u_int32_t, isn_offset_old); 1564 1565 #define V_isn_secret VNET(isn_secret) 1566 #define V_isn_last VNET(isn_last) 1567 #define V_isn_last_reseed VNET(isn_last_reseed) 1568 #define V_isn_offset VNET(isn_offset) 1569 #define V_isn_offset_old VNET(isn_offset_old) 1570 1571 tcp_seq 1572 tcp_new_isn(struct tcpcb *tp) 1573 { 1574 MD5_CTX isn_ctx; 1575 u_int32_t md5_buffer[4]; 1576 tcp_seq new_isn; 1577 u_int32_t projected_offset; 1578 1579 INP_WLOCK_ASSERT(tp->t_inpcb); 1580 1581 ISN_LOCK(); 1582 /* Seed if this is the first use, reseed if requested. */ 1583 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) && 1584 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz) 1585 < (u_int)ticks))) { 1586 read_random(&V_isn_secret, sizeof(V_isn_secret)); 1587 V_isn_last_reseed = ticks; 1588 } 1589 1590 /* Compute the md5 hash and return the ISN. */ 1591 MD5Init(&isn_ctx); 1592 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1593 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1594 #ifdef INET6 1595 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1596 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1597 sizeof(struct in6_addr)); 1598 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1599 sizeof(struct in6_addr)); 1600 } else 1601 #endif 1602 { 1603 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1604 sizeof(struct in_addr)); 1605 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1606 sizeof(struct in_addr)); 1607 } 1608 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret)); 1609 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1610 new_isn = (tcp_seq) md5_buffer[0]; 1611 V_isn_offset += ISN_STATIC_INCREMENT + 1612 (arc4random() & ISN_RANDOM_INCREMENT); 1613 if (ticks != V_isn_last) { 1614 projected_offset = V_isn_offset_old + 1615 ISN_BYTES_PER_SECOND / hz * (ticks - V_isn_last); 1616 if (SEQ_GT(projected_offset, V_isn_offset)) 1617 V_isn_offset = projected_offset; 1618 V_isn_offset_old = V_isn_offset; 1619 V_isn_last = ticks; 1620 } 1621 new_isn += V_isn_offset; 1622 ISN_UNLOCK(); 1623 return (new_isn); 1624 } 1625 1626 /* 1627 * When a specific ICMP unreachable message is received and the 1628 * connection state is SYN-SENT, drop the connection. This behavior 1629 * is controlled by the icmp_may_rst sysctl. 1630 */ 1631 struct inpcb * 1632 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1633 { 1634 struct tcpcb *tp; 1635 1636 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 1637 INP_WLOCK_ASSERT(inp); 1638 1639 if ((inp->inp_flags & INP_TIMEWAIT) || 1640 (inp->inp_flags & INP_DROPPED)) 1641 return (inp); 1642 1643 tp = intotcpcb(inp); 1644 if (tp->t_state != TCPS_SYN_SENT) 1645 return (inp); 1646 1647 tp = tcp_drop(tp, errno); 1648 if (tp != NULL) 1649 return (inp); 1650 else 1651 return (NULL); 1652 } 1653 1654 /* 1655 * When `need fragmentation' ICMP is received, update our idea of the MSS 1656 * based on the new value in the route. Also nudge TCP to send something, 1657 * since we know the packet we just sent was dropped. 1658 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1659 */ 1660 struct inpcb * 1661 tcp_mtudisc(struct inpcb *inp, int errno) 1662 { 1663 struct tcpcb *tp; 1664 struct socket *so; 1665 1666 INP_WLOCK_ASSERT(inp); 1667 if ((inp->inp_flags & INP_TIMEWAIT) || 1668 (inp->inp_flags & INP_DROPPED)) 1669 return (inp); 1670 1671 tp = intotcpcb(inp); 1672 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1673 1674 tcp_mss_update(tp, -1, NULL, NULL); 1675 1676 so = inp->inp_socket; 1677 SOCKBUF_LOCK(&so->so_snd); 1678 /* If the mss is larger than the socket buffer, decrease the mss. */ 1679 if (so->so_snd.sb_hiwat < tp->t_maxseg) 1680 tp->t_maxseg = so->so_snd.sb_hiwat; 1681 SOCKBUF_UNLOCK(&so->so_snd); 1682 1683 TCPSTAT_INC(tcps_mturesent); 1684 tp->t_rtttime = 0; 1685 tp->snd_nxt = tp->snd_una; 1686 tcp_free_sackholes(tp); 1687 tp->snd_recover = tp->snd_max; 1688 if (tp->t_flags & TF_SACK_PERMIT) 1689 EXIT_FASTRECOVERY(tp->t_flags); 1690 tcp_output_send(tp); 1691 return (inp); 1692 } 1693 1694 #ifdef INET 1695 /* 1696 * Look-up the routing entry to the peer of this inpcb. If no route 1697 * is found and it cannot be allocated, then return 0. This routine 1698 * is called by TCP routines that access the rmx structure and by 1699 * tcp_mss_update to get the peer/interface MTU. 1700 */ 1701 u_long 1702 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1703 { 1704 struct route sro; 1705 struct sockaddr_in *dst; 1706 struct ifnet *ifp; 1707 u_long maxmtu = 0; 1708 1709 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1710 1711 bzero(&sro, sizeof(sro)); 1712 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1713 dst = (struct sockaddr_in *)&sro.ro_dst; 1714 dst->sin_family = AF_INET; 1715 dst->sin_len = sizeof(*dst); 1716 dst->sin_addr = inc->inc_faddr; 1717 in_rtalloc_ign(&sro, 0, inc->inc_fibnum); 1718 } 1719 if (sro.ro_rt != NULL) { 1720 ifp = sro.ro_rt->rt_ifp; 1721 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1722 maxmtu = ifp->if_mtu; 1723 else 1724 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1725 1726 /* Report additional interface capabilities. */ 1727 if (flags != NULL) { 1728 if (ifp->if_capenable & IFCAP_TSO4 && 1729 ifp->if_hwassist & CSUM_TSO) 1730 *flags |= CSUM_TSO; 1731 } 1732 RTFREE(sro.ro_rt); 1733 } 1734 return (maxmtu); 1735 } 1736 #endif /* INET */ 1737 1738 #ifdef INET6 1739 u_long 1740 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1741 { 1742 struct route_in6 sro6; 1743 struct ifnet *ifp; 1744 u_long maxmtu = 0; 1745 1746 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1747 1748 bzero(&sro6, sizeof(sro6)); 1749 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1750 sro6.ro_dst.sin6_family = AF_INET6; 1751 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1752 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1753 rtalloc_ign((struct route *)&sro6, 0); 1754 } 1755 if (sro6.ro_rt != NULL) { 1756 ifp = sro6.ro_rt->rt_ifp; 1757 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1758 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1759 else 1760 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1761 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1762 1763 /* Report additional interface capabilities. */ 1764 if (flags != NULL) { 1765 if (ifp->if_capenable & IFCAP_TSO6 && 1766 ifp->if_hwassist & CSUM_TSO) 1767 *flags |= CSUM_TSO; 1768 } 1769 RTFREE(sro6.ro_rt); 1770 } 1771 1772 return (maxmtu); 1773 } 1774 #endif /* INET6 */ 1775 1776 #ifdef IPSEC 1777 /* compute ESP/AH header size for TCP, including outer IP header. */ 1778 size_t 1779 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1780 { 1781 struct inpcb *inp; 1782 struct mbuf *m; 1783 size_t hdrsiz; 1784 struct ip *ip; 1785 #ifdef INET6 1786 struct ip6_hdr *ip6; 1787 #endif 1788 struct tcphdr *th; 1789 1790 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1791 return (0); 1792 MGETHDR(m, M_DONTWAIT, MT_DATA); 1793 if (!m) 1794 return (0); 1795 1796 #ifdef INET6 1797 if ((inp->inp_vflag & INP_IPV6) != 0) { 1798 ip6 = mtod(m, struct ip6_hdr *); 1799 th = (struct tcphdr *)(ip6 + 1); 1800 m->m_pkthdr.len = m->m_len = 1801 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1802 tcpip_fillheaders(inp, ip6, th); 1803 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1804 } else 1805 #endif /* INET6 */ 1806 { 1807 ip = mtod(m, struct ip *); 1808 th = (struct tcphdr *)(ip + 1); 1809 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1810 tcpip_fillheaders(inp, ip, th); 1811 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1812 } 1813 1814 m_free(m); 1815 return (hdrsiz); 1816 } 1817 #endif /* IPSEC */ 1818 1819 #ifdef TCP_SIGNATURE 1820 /* 1821 * Callback function invoked by m_apply() to digest TCP segment data 1822 * contained within an mbuf chain. 1823 */ 1824 static int 1825 tcp_signature_apply(void *fstate, void *data, u_int len) 1826 { 1827 1828 MD5Update(fstate, (u_char *)data, len); 1829 return (0); 1830 } 1831 1832 /* 1833 * Compute TCP-MD5 hash of a TCP segment. (RFC2385) 1834 * 1835 * Parameters: 1836 * m pointer to head of mbuf chain 1837 * _unused 1838 * len length of TCP segment data, excluding options 1839 * optlen length of TCP segment options 1840 * buf pointer to storage for computed MD5 digest 1841 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 1842 * 1843 * We do this over ip, tcphdr, segment data, and the key in the SADB. 1844 * When called from tcp_input(), we can be sure that th_sum has been 1845 * zeroed out and verified already. 1846 * 1847 * Return 0 if successful, otherwise return -1. 1848 * 1849 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 1850 * search with the destination IP address, and a 'magic SPI' to be 1851 * determined by the application. This is hardcoded elsewhere to 1179 1852 * right now. Another branch of this code exists which uses the SPD to 1853 * specify per-application flows but it is unstable. 1854 */ 1855 int 1856 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen, 1857 u_char *buf, u_int direction) 1858 { 1859 union sockaddr_union dst; 1860 #ifdef INET 1861 struct ippseudo ippseudo; 1862 #endif 1863 MD5_CTX ctx; 1864 int doff; 1865 struct ip *ip; 1866 #ifdef INET 1867 struct ipovly *ipovly; 1868 #endif 1869 struct secasvar *sav; 1870 struct tcphdr *th; 1871 #ifdef INET6 1872 struct ip6_hdr *ip6; 1873 struct in6_addr in6; 1874 char ip6buf[INET6_ADDRSTRLEN]; 1875 uint32_t plen; 1876 uint16_t nhdr; 1877 #endif 1878 u_short savecsum; 1879 1880 KASSERT(m != NULL, ("NULL mbuf chain")); 1881 KASSERT(buf != NULL, ("NULL signature pointer")); 1882 1883 /* Extract the destination from the IP header in the mbuf. */ 1884 bzero(&dst, sizeof(union sockaddr_union)); 1885 ip = mtod(m, struct ip *); 1886 #ifdef INET6 1887 ip6 = NULL; /* Make the compiler happy. */ 1888 #endif 1889 switch (ip->ip_v) { 1890 #ifdef INET 1891 case IPVERSION: 1892 dst.sa.sa_len = sizeof(struct sockaddr_in); 1893 dst.sa.sa_family = AF_INET; 1894 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 1895 ip->ip_src : ip->ip_dst; 1896 break; 1897 #endif 1898 #ifdef INET6 1899 case (IPV6_VERSION >> 4): 1900 ip6 = mtod(m, struct ip6_hdr *); 1901 dst.sa.sa_len = sizeof(struct sockaddr_in6); 1902 dst.sa.sa_family = AF_INET6; 1903 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ? 1904 ip6->ip6_src : ip6->ip6_dst; 1905 break; 1906 #endif 1907 default: 1908 return (EINVAL); 1909 /* NOTREACHED */ 1910 break; 1911 } 1912 1913 /* Look up an SADB entry which matches the address of the peer. */ 1914 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 1915 if (sav == NULL) { 1916 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__, 1917 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) : 1918 #ifdef INET6 1919 (ip->ip_v == (IPV6_VERSION >> 4)) ? 1920 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) : 1921 #endif 1922 "(unsupported)")); 1923 return (EINVAL); 1924 } 1925 1926 MD5Init(&ctx); 1927 /* 1928 * Step 1: Update MD5 hash with IP(v6) pseudo-header. 1929 * 1930 * XXX The ippseudo header MUST be digested in network byte order, 1931 * or else we'll fail the regression test. Assume all fields we've 1932 * been doing arithmetic on have been in host byte order. 1933 * XXX One cannot depend on ipovly->ih_len here. When called from 1934 * tcp_output(), the underlying ip_len member has not yet been set. 1935 */ 1936 switch (ip->ip_v) { 1937 #ifdef INET 1938 case IPVERSION: 1939 ipovly = (struct ipovly *)ip; 1940 ippseudo.ippseudo_src = ipovly->ih_src; 1941 ippseudo.ippseudo_dst = ipovly->ih_dst; 1942 ippseudo.ippseudo_pad = 0; 1943 ippseudo.ippseudo_p = IPPROTO_TCP; 1944 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + 1945 optlen); 1946 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 1947 1948 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip)); 1949 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen; 1950 break; 1951 #endif 1952 #ifdef INET6 1953 /* 1954 * RFC 2385, 2.0 Proposal 1955 * For IPv6, the pseudo-header is as described in RFC 2460, namely the 1956 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero- 1957 * extended next header value (to form 32 bits), and 32-bit segment 1958 * length. 1959 * Note: Upper-Layer Packet Length comes before Next Header. 1960 */ 1961 case (IPV6_VERSION >> 4): 1962 in6 = ip6->ip6_src; 1963 in6_clearscope(&in6); 1964 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 1965 in6 = ip6->ip6_dst; 1966 in6_clearscope(&in6); 1967 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 1968 plen = htonl(len + sizeof(struct tcphdr) + optlen); 1969 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t)); 1970 nhdr = 0; 1971 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 1972 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 1973 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 1974 nhdr = IPPROTO_TCP; 1975 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 1976 1977 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr)); 1978 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen; 1979 break; 1980 #endif 1981 default: 1982 return (EINVAL); 1983 /* NOTREACHED */ 1984 break; 1985 } 1986 1987 1988 /* 1989 * Step 2: Update MD5 hash with TCP header, excluding options. 1990 * The TCP checksum must be set to zero. 1991 */ 1992 savecsum = th->th_sum; 1993 th->th_sum = 0; 1994 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 1995 th->th_sum = savecsum; 1996 1997 /* 1998 * Step 3: Update MD5 hash with TCP segment data. 1999 * Use m_apply() to avoid an early m_pullup(). 2000 */ 2001 if (len > 0) 2002 m_apply(m, doff, len, tcp_signature_apply, &ctx); 2003 2004 /* 2005 * Step 4: Update MD5 hash with shared secret. 2006 */ 2007 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 2008 MD5Final(buf, &ctx); 2009 2010 key_sa_recordxfer(sav, m); 2011 KEY_FREESAV(&sav); 2012 return (0); 2013 } 2014 2015 /* 2016 * Verify the TCP-MD5 hash of a TCP segment. (RFC2385) 2017 * 2018 * Parameters: 2019 * m pointer to head of mbuf chain 2020 * len length of TCP segment data, excluding options 2021 * optlen length of TCP segment options 2022 * buf pointer to storage for computed MD5 digest 2023 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 2024 * 2025 * Return 1 if successful, otherwise return 0. 2026 */ 2027 int 2028 tcp_signature_verify(struct mbuf *m, int off0, int tlen, int optlen, 2029 struct tcpopt *to, struct tcphdr *th, u_int tcpbflag) 2030 { 2031 char tmpdigest[TCP_SIGLEN]; 2032 2033 if (tcp_sig_checksigs == 0) 2034 return (1); 2035 if ((tcpbflag & TF_SIGNATURE) == 0) { 2036 if ((to->to_flags & TOF_SIGNATURE) != 0) { 2037 2038 /* 2039 * If this socket is not expecting signature but 2040 * the segment contains signature just fail. 2041 */ 2042 TCPSTAT_INC(tcps_sig_err_sigopt); 2043 TCPSTAT_INC(tcps_sig_rcvbadsig); 2044 return (0); 2045 } 2046 2047 /* Signature is not expected, and not present in segment. */ 2048 return (1); 2049 } 2050 2051 /* 2052 * If this socket is expecting signature but the segment does not 2053 * contain any just fail. 2054 */ 2055 if ((to->to_flags & TOF_SIGNATURE) == 0) { 2056 TCPSTAT_INC(tcps_sig_err_nosigopt); 2057 TCPSTAT_INC(tcps_sig_rcvbadsig); 2058 return (0); 2059 } 2060 if (tcp_signature_compute(m, off0, tlen, optlen, &tmpdigest[0], 2061 IPSEC_DIR_INBOUND) == -1) { 2062 TCPSTAT_INC(tcps_sig_err_buildsig); 2063 TCPSTAT_INC(tcps_sig_rcvbadsig); 2064 return (0); 2065 } 2066 2067 if (bcmp(to->to_signature, &tmpdigest[0], TCP_SIGLEN) != 0) { 2068 TCPSTAT_INC(tcps_sig_rcvbadsig); 2069 return (0); 2070 } 2071 TCPSTAT_INC(tcps_sig_rcvgoodsig); 2072 return (1); 2073 } 2074 #endif /* TCP_SIGNATURE */ 2075 2076 static int 2077 sysctl_drop(SYSCTL_HANDLER_ARGS) 2078 { 2079 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 2080 struct sockaddr_storage addrs[2]; 2081 struct inpcb *inp; 2082 struct tcpcb *tp; 2083 struct tcptw *tw; 2084 struct sockaddr_in *fin, *lin; 2085 #ifdef INET6 2086 struct sockaddr_in6 *fin6, *lin6; 2087 #endif 2088 int error; 2089 2090 inp = NULL; 2091 fin = lin = NULL; 2092 #ifdef INET6 2093 fin6 = lin6 = NULL; 2094 #endif 2095 error = 0; 2096 2097 if (req->oldptr != NULL || req->oldlen != 0) 2098 return (EINVAL); 2099 if (req->newptr == NULL) 2100 return (EPERM); 2101 if (req->newlen < sizeof(addrs)) 2102 return (ENOMEM); 2103 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2104 if (error) 2105 return (error); 2106 2107 switch (addrs[0].ss_family) { 2108 #ifdef INET6 2109 case AF_INET6: 2110 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2111 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2112 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2113 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2114 return (EINVAL); 2115 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2116 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2117 return (EINVAL); 2118 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2119 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2120 fin = (struct sockaddr_in *)&addrs[0]; 2121 lin = (struct sockaddr_in *)&addrs[1]; 2122 break; 2123 } 2124 error = sa6_embedscope(fin6, V_ip6_use_defzone); 2125 if (error) 2126 return (error); 2127 error = sa6_embedscope(lin6, V_ip6_use_defzone); 2128 if (error) 2129 return (error); 2130 break; 2131 #endif 2132 #ifdef INET 2133 case AF_INET: 2134 fin = (struct sockaddr_in *)&addrs[0]; 2135 lin = (struct sockaddr_in *)&addrs[1]; 2136 if (fin->sin_len != sizeof(struct sockaddr_in) || 2137 lin->sin_len != sizeof(struct sockaddr_in)) 2138 return (EINVAL); 2139 break; 2140 #endif 2141 default: 2142 return (EINVAL); 2143 } 2144 INP_INFO_WLOCK(&V_tcbinfo); 2145 switch (addrs[0].ss_family) { 2146 #ifdef INET6 2147 case AF_INET6: 2148 inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr, 2149 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port, 2150 INPLOOKUP_WLOCKPCB, NULL); 2151 break; 2152 #endif 2153 #ifdef INET 2154 case AF_INET: 2155 inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port, 2156 lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL); 2157 break; 2158 #endif 2159 } 2160 if (inp != NULL) { 2161 if (inp->inp_flags & INP_TIMEWAIT) { 2162 /* 2163 * XXXRW: There currently exists a state where an 2164 * inpcb is present, but its timewait state has been 2165 * discarded. For now, don't allow dropping of this 2166 * type of inpcb. 2167 */ 2168 tw = intotw(inp); 2169 if (tw != NULL) 2170 tcp_twclose(tw, 0); 2171 else 2172 INP_WUNLOCK(inp); 2173 } else if (!(inp->inp_flags & INP_DROPPED) && 2174 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2175 tp = intotcpcb(inp); 2176 tp = tcp_drop(tp, ECONNABORTED); 2177 if (tp != NULL) 2178 INP_WUNLOCK(inp); 2179 } else 2180 INP_WUNLOCK(inp); 2181 } else 2182 error = ESRCH; 2183 INP_INFO_WUNLOCK(&V_tcbinfo); 2184 return (error); 2185 } 2186 2187 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2188 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2189 0, sysctl_drop, "", "Drop TCP connection"); 2190 2191 /* 2192 * Generate a standardized TCP log line for use throughout the 2193 * tcp subsystem. Memory allocation is done with M_NOWAIT to 2194 * allow use in the interrupt context. 2195 * 2196 * NB: The caller MUST free(s, M_TCPLOG) the returned string. 2197 * NB: The function may return NULL if memory allocation failed. 2198 * 2199 * Due to header inclusion and ordering limitations the struct ip 2200 * and ip6_hdr pointers have to be passed as void pointers. 2201 */ 2202 char * 2203 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2204 const void *ip6hdr) 2205 { 2206 2207 /* Is logging enabled? */ 2208 if (tcp_log_in_vain == 0) 2209 return (NULL); 2210 2211 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr)); 2212 } 2213 2214 char * 2215 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2216 const void *ip6hdr) 2217 { 2218 2219 /* Is logging enabled? */ 2220 if (tcp_log_debug == 0) 2221 return (NULL); 2222 2223 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr)); 2224 } 2225 2226 static char * 2227 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2228 const void *ip6hdr) 2229 { 2230 char *s, *sp; 2231 size_t size; 2232 struct ip *ip; 2233 #ifdef INET6 2234 const struct ip6_hdr *ip6; 2235 2236 ip6 = (const struct ip6_hdr *)ip6hdr; 2237 #endif /* INET6 */ 2238 ip = (struct ip *)ip4hdr; 2239 2240 /* 2241 * The log line looks like this: 2242 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>" 2243 */ 2244 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") + 2245 sizeof(PRINT_TH_FLAGS) + 1 + 2246 #ifdef INET6 2247 2 * INET6_ADDRSTRLEN; 2248 #else 2249 2 * INET_ADDRSTRLEN; 2250 #endif /* INET6 */ 2251 2252 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT); 2253 if (s == NULL) 2254 return (NULL); 2255 2256 strcat(s, "TCP: ["); 2257 sp = s + strlen(s); 2258 2259 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) { 2260 inet_ntoa_r(inc->inc_faddr, sp); 2261 sp = s + strlen(s); 2262 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2263 sp = s + strlen(s); 2264 inet_ntoa_r(inc->inc_laddr, sp); 2265 sp = s + strlen(s); 2266 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2267 #ifdef INET6 2268 } else if (inc) { 2269 ip6_sprintf(sp, &inc->inc6_faddr); 2270 sp = s + strlen(s); 2271 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2272 sp = s + strlen(s); 2273 ip6_sprintf(sp, &inc->inc6_laddr); 2274 sp = s + strlen(s); 2275 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2276 } else if (ip6 && th) { 2277 ip6_sprintf(sp, &ip6->ip6_src); 2278 sp = s + strlen(s); 2279 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2280 sp = s + strlen(s); 2281 ip6_sprintf(sp, &ip6->ip6_dst); 2282 sp = s + strlen(s); 2283 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2284 #endif /* INET6 */ 2285 #ifdef INET 2286 } else if (ip && th) { 2287 inet_ntoa_r(ip->ip_src, sp); 2288 sp = s + strlen(s); 2289 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2290 sp = s + strlen(s); 2291 inet_ntoa_r(ip->ip_dst, sp); 2292 sp = s + strlen(s); 2293 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2294 #endif /* INET */ 2295 } else { 2296 free(s, M_TCPLOG); 2297 return (NULL); 2298 } 2299 sp = s + strlen(s); 2300 if (th) 2301 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS); 2302 if (*(s + size - 1) != '\0') 2303 panic("%s: string too long", __func__); 2304 return (s); 2305 } 2306