Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet/tcp_subr.c
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1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD: releng/7.4/sys/netinet/tcp_subr.c 214878 2010-11-06 13:46:58Z lstewart $"); 34 35 #include "opt_compat.h" 36 #include "opt_inet.h" 37 #include "opt_inet6.h" 38 #include "opt_ipsec.h" 39 #include "opt_mac.h" 40 #include "opt_tcpdebug.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/callout.h> 45 #include <sys/kernel.h> 46 #include <sys/sysctl.h> 47 #include <sys/malloc.h> 48 #include <sys/mbuf.h> 49 #ifdef INET6 50 #include <sys/domain.h> 51 #endif 52 #include <sys/priv.h> 53 #include <sys/proc.h> 54 #include <sys/socket.h> 55 #include <sys/socketvar.h> 56 #include <sys/protosw.h> 57 #include <sys/random.h> 58 59 #include <vm/uma.h> 60 61 #include <net/route.h> 62 #include <net/if.h> 63 64 #include <netinet/in.h> 65 #include <netinet/in_systm.h> 66 #include <netinet/ip.h> 67 #ifdef INET6 68 #include <netinet/ip6.h> 69 #endif 70 #include <netinet/in_pcb.h> 71 #ifdef INET6 72 #include <netinet6/in6_pcb.h> 73 #endif 74 #include <netinet/in_var.h> 75 #include <netinet/ip_var.h> 76 #ifdef INET6 77 #include <netinet6/ip6_var.h> 78 #include <netinet6/scope6_var.h> 79 #include <netinet6/nd6.h> 80 #endif 81 #include <netinet/ip_icmp.h> 82 #include <netinet/tcp.h> 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 #include <netinet6/ip6protosw.h> 97 98 #ifdef IPSEC 99 #include <netipsec/ipsec.h> 100 #include <netipsec/xform.h> 101 #ifdef INET6 102 #include <netipsec/ipsec6.h> 103 #endif 104 #include <netipsec/key.h> 105 #include <sys/syslog.h> 106 #endif /*IPSEC*/ 107 108 #include <machine/in_cksum.h> 109 #include <sys/md5.h> 110 111 #include <security/mac/mac_framework.h> 112 113 int tcp_mssdflt = TCP_MSS; 114 #ifdef INET6 115 int tcp_v6mssdflt = TCP6_MSS; 116 #endif 117 118 static int 119 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS) 120 { 121 int error, new; 122 123 new = tcp_mssdflt; 124 error = sysctl_handle_int(oidp, &new, 0, req); 125 if (error == 0 && req->newptr) { 126 if (new < TCP_MINMSS) 127 error = EINVAL; 128 else 129 tcp_mssdflt = new; 130 } 131 return (error); 132 } 133 134 SYSCTL_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLTYPE_INT|CTLFLAG_RW, 135 &tcp_mssdflt, 0, &sysctl_net_inet_tcp_mss_check, "I", 136 "Default TCP Maximum Segment Size"); 137 138 #ifdef INET6 139 static int 140 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS) 141 { 142 int error, new; 143 144 new = tcp_v6mssdflt; 145 error = sysctl_handle_int(oidp, &new, 0, req); 146 if (error == 0 && req->newptr) { 147 if (new < TCP_MINMSS) 148 error = EINVAL; 149 else 150 tcp_v6mssdflt = new; 151 } 152 return (error); 153 } 154 155 SYSCTL_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLTYPE_INT|CTLFLAG_RW, 156 &tcp_v6mssdflt, 0, &sysctl_net_inet_tcp_mss_v6_check, "I", 157 "Default TCP Maximum Segment Size for IPv6"); 158 #endif 159 160 /* 161 * Minimum MSS we accept and use. This prevents DoS attacks where 162 * we are forced to a ridiculous low MSS like 20 and send hundreds 163 * of packets instead of one. The effect scales with the available 164 * bandwidth and quickly saturates the CPU and network interface 165 * with packet generation and sending. Set to zero to disable MINMSS 166 * checking. This setting prevents us from sending too small packets. 167 */ 168 int tcp_minmss = TCP_MINMSS; 169 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 170 &tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 171 172 int tcp_do_rfc1323 = 1; 173 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 174 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions"); 175 176 static int tcp_log_debug = 0; 177 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW, 178 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments"); 179 180 static int tcp_tcbhashsize = 0; 181 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 182 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 183 184 static int do_tcpdrain = 1; 185 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, 186 &do_tcpdrain, 0, 187 "Enable tcp_drain routine for extra help when low on mbufs"); 188 189 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 190 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 191 192 static int icmp_may_rst = 1; 193 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, 194 &icmp_may_rst, 0, 195 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 196 197 static int tcp_isn_reseed_interval = 0; 198 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 199 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 200 201 /* 202 * TCP bandwidth limiting sysctls. Note that the default lower bound of 203 * 1024 exists only for debugging. A good production default would be 204 * something like 6100. 205 */ 206 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0, 207 "TCP inflight data limiting"); 208 209 static int tcp_inflight_enable = 0; 210 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, enable, CTLFLAG_RW, 211 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 212 213 static int tcp_inflight_debug = 0; 214 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW, 215 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 216 217 static int tcp_inflight_rttthresh; 218 SYSCTL_PROC(_net_inet_tcp_inflight, OID_AUTO, rttthresh, CTLTYPE_INT|CTLFLAG_RW, 219 &tcp_inflight_rttthresh, 0, sysctl_msec_to_ticks, "I", 220 "RTT threshold below which inflight will deactivate itself"); 221 222 static int tcp_inflight_min = 6144; 223 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, min, CTLFLAG_RW, 224 &tcp_inflight_min, 0, "Lower-bound for TCP inflight window"); 225 226 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 227 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, max, CTLFLAG_RW, 228 &tcp_inflight_max, 0, "Upper-bound for TCP inflight window"); 229 230 static int tcp_inflight_stab = 20; 231 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, stab, CTLFLAG_RW, 232 &tcp_inflight_stab, 0, "Inflight Algorithm Stabilization 20 = 2 packets"); 233 234 uma_zone_t sack_hole_zone; 235 236 static struct inpcb *tcp_notify(struct inpcb *, int); 237 static void tcp_isn_tick(void *); 238 static char * tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, 239 void *ip4hdr, const void *ip6hdr); 240 241 /* 242 * Target size of TCP PCB hash tables. Must be a power of two. 243 * 244 * Note that this can be overridden by the kernel environment 245 * variable net.inet.tcp.tcbhashsize 246 */ 247 #ifndef TCBHASHSIZE 248 #define TCBHASHSIZE 512 249 #endif 250 251 /* 252 * XXX 253 * Callouts should be moved into struct tcp directly. They are currently 254 * separate because the tcpcb structure is exported to userland for sysctl 255 * parsing purposes, which do not know about callouts. 256 */ 257 struct tcpcb_mem { 258 struct tcpcb tcb; 259 struct tcp_timer tt; 260 }; 261 262 static uma_zone_t tcpcb_zone; 263 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers"); 264 struct callout isn_callout; 265 static struct mtx isn_mtx; 266 267 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 268 #define ISN_LOCK() mtx_lock(&isn_mtx) 269 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 270 271 /* 272 * TCP initialization. 273 */ 274 static void 275 tcp_zone_change(void *tag) 276 { 277 278 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 279 uma_zone_set_max(tcpcb_zone, maxsockets); 280 tcp_tw_zone_change(); 281 } 282 283 static int 284 tcp_inpcb_init(void *mem, int size, int flags) 285 { 286 struct inpcb *inp = mem; 287 288 INP_LOCK_INIT(inp, "inp", "tcpinp"); 289 return (0); 290 } 291 292 void 293 tcp_init(void) 294 { 295 296 int hashsize = TCBHASHSIZE; 297 tcp_delacktime = TCPTV_DELACK; 298 tcp_keepinit = TCPTV_KEEP_INIT; 299 tcp_keepidle = TCPTV_KEEP_IDLE; 300 tcp_keepintvl = TCPTV_KEEPINTVL; 301 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 302 tcp_msl = TCPTV_MSL; 303 tcp_rexmit_min = TCPTV_MIN; 304 if (tcp_rexmit_min < 1) 305 tcp_rexmit_min = 1; 306 tcp_rexmit_slop = TCPTV_CPU_VAR; 307 tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 308 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 309 310 INP_INFO_LOCK_INIT(&tcbinfo, "tcp"); 311 LIST_INIT(&tcb); 312 tcbinfo.ipi_listhead = &tcb; 313 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 314 if (!powerof2(hashsize)) { 315 printf("WARNING: TCB hash size not a power of 2\n"); 316 hashsize = 512; /* safe default */ 317 } 318 tcp_tcbhashsize = hashsize; 319 tcbinfo.ipi_hashbase = hashinit(hashsize, M_PCB, 320 &tcbinfo.ipi_hashmask); 321 tcbinfo.ipi_porthashbase = hashinit(hashsize, M_PCB, 322 &tcbinfo.ipi_porthashmask); 323 tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb), 324 NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 325 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 326 #ifdef INET6 327 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 328 #else /* INET6 */ 329 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 330 #endif /* INET6 */ 331 if (max_protohdr < TCP_MINPROTOHDR) 332 max_protohdr = TCP_MINPROTOHDR; 333 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 334 panic("tcp_init"); 335 #undef TCP_MINPROTOHDR 336 /* 337 * These have to be type stable for the benefit of the timers. 338 */ 339 tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 340 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 341 uma_zone_set_max(tcpcb_zone, maxsockets); 342 tcp_tw_init(); 343 syncache_init(); 344 tcp_hc_init(); 345 tcp_reass_init(); 346 ISN_LOCK_INIT(); 347 callout_init(&isn_callout, CALLOUT_MPSAFE); 348 tcp_isn_tick(NULL); 349 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 350 SHUTDOWN_PRI_DEFAULT); 351 sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 352 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 353 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 354 EVENTHANDLER_PRI_ANY); 355 } 356 357 void 358 tcp_fini(void *xtp) 359 { 360 361 callout_stop(&isn_callout); 362 } 363 364 /* 365 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 366 * tcp_template used to store this data in mbufs, but we now recopy it out 367 * of the tcpcb each time to conserve mbufs. 368 */ 369 void 370 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 371 { 372 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 373 374 INP_WLOCK_ASSERT(inp); 375 376 #ifdef INET6 377 if ((inp->inp_vflag & INP_IPV6) != 0) { 378 struct ip6_hdr *ip6; 379 380 ip6 = (struct ip6_hdr *)ip_ptr; 381 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 382 (inp->inp_flow & IPV6_FLOWINFO_MASK); 383 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 384 (IPV6_VERSION & IPV6_VERSION_MASK); 385 ip6->ip6_nxt = IPPROTO_TCP; 386 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 387 ip6->ip6_src = inp->in6p_laddr; 388 ip6->ip6_dst = inp->in6p_faddr; 389 } else 390 #endif 391 { 392 struct ip *ip; 393 394 ip = (struct ip *)ip_ptr; 395 ip->ip_v = IPVERSION; 396 ip->ip_hl = 5; 397 ip->ip_tos = inp->inp_ip_tos; 398 ip->ip_len = 0; 399 ip->ip_id = 0; 400 ip->ip_off = 0; 401 ip->ip_ttl = inp->inp_ip_ttl; 402 ip->ip_sum = 0; 403 ip->ip_p = IPPROTO_TCP; 404 ip->ip_src = inp->inp_laddr; 405 ip->ip_dst = inp->inp_faddr; 406 } 407 th->th_sport = inp->inp_lport; 408 th->th_dport = inp->inp_fport; 409 th->th_seq = 0; 410 th->th_ack = 0; 411 th->th_x2 = 0; 412 th->th_off = 5; 413 th->th_flags = 0; 414 th->th_win = 0; 415 th->th_urp = 0; 416 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 417 } 418 419 /* 420 * Create template to be used to send tcp packets on a connection. 421 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 422 * use for this function is in keepalives, which use tcp_respond. 423 */ 424 struct tcptemp * 425 tcpip_maketemplate(struct inpcb *inp) 426 { 427 struct tcptemp *t; 428 429 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT); 430 if (t == NULL) 431 return (NULL); 432 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t); 433 return (t); 434 } 435 436 /* 437 * Send a single message to the TCP at address specified by 438 * the given TCP/IP header. If m == NULL, then we make a copy 439 * of the tcpiphdr at ti and send directly to the addressed host. 440 * This is used to force keep alive messages out using the TCP 441 * template for a connection. If flags are given then we send 442 * a message back to the TCP which originated the * segment ti, 443 * and discard the mbuf containing it and any other attached mbufs. 444 * 445 * In any case the ack and sequence number of the transmitted 446 * segment are as specified by the parameters. 447 * 448 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 449 */ 450 void 451 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 452 tcp_seq ack, tcp_seq seq, int flags) 453 { 454 int tlen; 455 int win = 0; 456 struct ip *ip; 457 struct tcphdr *nth; 458 #ifdef INET6 459 struct ip6_hdr *ip6; 460 int isipv6; 461 #endif /* INET6 */ 462 int ipflags = 0; 463 struct inpcb *inp; 464 465 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 466 467 #ifdef INET6 468 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 469 ip6 = ipgen; 470 #endif /* INET6 */ 471 ip = ipgen; 472 473 if (tp != NULL) { 474 inp = tp->t_inpcb; 475 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 476 INP_WLOCK_ASSERT(inp); 477 } else 478 inp = NULL; 479 480 if (tp != NULL) { 481 if (!(flags & TH_RST)) { 482 win = sbspace(&inp->inp_socket->so_rcv); 483 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 484 win = (long)TCP_MAXWIN << tp->rcv_scale; 485 } 486 } 487 if (m == NULL) { 488 m = m_gethdr(M_DONTWAIT, MT_DATA); 489 if (m == NULL) 490 return; 491 tlen = 0; 492 m->m_data += max_linkhdr; 493 #ifdef INET6 494 if (isipv6) { 495 bcopy((caddr_t)ip6, mtod(m, caddr_t), 496 sizeof(struct ip6_hdr)); 497 ip6 = mtod(m, struct ip6_hdr *); 498 nth = (struct tcphdr *)(ip6 + 1); 499 } else 500 #endif /* INET6 */ 501 { 502 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 503 ip = mtod(m, struct ip *); 504 nth = (struct tcphdr *)(ip + 1); 505 } 506 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 507 flags = TH_ACK; 508 } else { 509 /* 510 * reuse the mbuf. 511 * XXX MRT We inherrit the FIB, which is lucky. 512 */ 513 m_freem(m->m_next); 514 m->m_next = NULL; 515 m->m_data = (caddr_t)ipgen; 516 /* m_len is set later */ 517 tlen = 0; 518 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 519 #ifdef INET6 520 if (isipv6) { 521 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 522 nth = (struct tcphdr *)(ip6 + 1); 523 } else 524 #endif /* INET6 */ 525 { 526 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t); 527 nth = (struct tcphdr *)(ip + 1); 528 } 529 if (th != nth) { 530 /* 531 * this is usually a case when an extension header 532 * exists between the IPv6 header and the 533 * TCP header. 534 */ 535 nth->th_sport = th->th_sport; 536 nth->th_dport = th->th_dport; 537 } 538 xchg(nth->th_dport, nth->th_sport, uint16_t); 539 #undef xchg 540 } 541 #ifdef INET6 542 if (isipv6) { 543 ip6->ip6_flow = 0; 544 ip6->ip6_vfc = IPV6_VERSION; 545 ip6->ip6_nxt = IPPROTO_TCP; 546 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 547 tlen)); 548 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 549 } else 550 #endif 551 { 552 tlen += sizeof (struct tcpiphdr); 553 ip->ip_len = tlen; 554 ip->ip_ttl = ip_defttl; 555 if (path_mtu_discovery) 556 ip->ip_off |= IP_DF; 557 } 558 m->m_len = tlen; 559 m->m_pkthdr.len = tlen; 560 m->m_pkthdr.rcvif = NULL; 561 #ifdef MAC 562 if (inp != NULL) { 563 /* 564 * Packet is associated with a socket, so allow the 565 * label of the response to reflect the socket label. 566 */ 567 INP_WLOCK_ASSERT(inp); 568 mac_create_mbuf_from_inpcb(inp, m); 569 } else { 570 /* 571 * Packet is not associated with a socket, so possibly 572 * update the label in place. 573 */ 574 mac_reflect_mbuf_tcp(m); 575 } 576 #endif 577 nth->th_seq = htonl(seq); 578 nth->th_ack = htonl(ack); 579 nth->th_x2 = 0; 580 nth->th_off = sizeof (struct tcphdr) >> 2; 581 nth->th_flags = flags; 582 if (tp != NULL) 583 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 584 else 585 nth->th_win = htons((u_short)win); 586 nth->th_urp = 0; 587 #ifdef INET6 588 if (isipv6) { 589 nth->th_sum = 0; 590 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 591 sizeof(struct ip6_hdr), 592 tlen - sizeof(struct ip6_hdr)); 593 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 594 NULL, NULL); 595 } else 596 #endif /* INET6 */ 597 { 598 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 599 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 600 m->m_pkthdr.csum_flags = CSUM_TCP; 601 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 602 } 603 #ifdef TCPDEBUG 604 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 605 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 606 #endif 607 #ifdef INET6 608 if (isipv6) 609 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 610 else 611 #endif /* INET6 */ 612 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 613 } 614 615 /* 616 * Create a new TCP control block, making an 617 * empty reassembly queue and hooking it to the argument 618 * protocol control block. The `inp' parameter must have 619 * come from the zone allocator set up in tcp_init(). 620 */ 621 struct tcpcb * 622 tcp_newtcpcb(struct inpcb *inp) 623 { 624 struct tcpcb_mem *tm; 625 struct tcpcb *tp; 626 #ifdef INET6 627 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 628 #endif /* INET6 */ 629 630 tm = uma_zalloc(tcpcb_zone, M_NOWAIT | M_ZERO); 631 if (tm == NULL) 632 return (NULL); 633 tp = &tm->tcb; 634 tp->t_timers = &tm->tt; 635 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 636 tp->t_maxseg = tp->t_maxopd = 637 #ifdef INET6 638 isipv6 ? tcp_v6mssdflt : 639 #endif /* INET6 */ 640 tcp_mssdflt; 641 642 /* Set up our timeouts. */ 643 callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE); 644 callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE); 645 callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE); 646 callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE); 647 callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE); 648 649 if (tcp_do_rfc1323) 650 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 651 if (tcp_do_sack) 652 tp->t_flags |= TF_SACK_PERMIT; 653 TAILQ_INIT(&tp->snd_holes); 654 tp->t_inpcb = inp; /* XXX */ 655 /* 656 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 657 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 658 * reasonable initial retransmit time. 659 */ 660 tp->t_srtt = TCPTV_SRTTBASE; 661 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 662 tp->t_rttmin = tcp_rexmit_min; 663 tp->t_rxtcur = TCPTV_RTOBASE; 664 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 665 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 666 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 667 tp->t_rcvtime = ticks; 668 tp->t_bw_rtttime = ticks; 669 /* 670 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 671 * because the socket may be bound to an IPv6 wildcard address, 672 * which may match an IPv4-mapped IPv6 address. 673 */ 674 inp->inp_ip_ttl = ip_defttl; 675 inp->inp_ppcb = tp; 676 return (tp); /* XXX */ 677 } 678 679 /* 680 * Drop a TCP connection, reporting 681 * the specified error. If connection is synchronized, 682 * then send a RST to peer. 683 */ 684 struct tcpcb * 685 tcp_drop(struct tcpcb *tp, int errno) 686 { 687 struct socket *so = tp->t_inpcb->inp_socket; 688 689 INP_INFO_WLOCK_ASSERT(&tcbinfo); 690 INP_WLOCK_ASSERT(tp->t_inpcb); 691 692 if (TCPS_HAVERCVDSYN(tp->t_state)) { 693 tp->t_state = TCPS_CLOSED; 694 (void) tcp_output_reset(tp); 695 tcpstat.tcps_drops++; 696 } else 697 tcpstat.tcps_conndrops++; 698 if (errno == ETIMEDOUT && tp->t_softerror) 699 errno = tp->t_softerror; 700 so->so_error = errno; 701 return (tcp_close(tp)); 702 } 703 704 void 705 tcp_discardcb(struct tcpcb *tp) 706 { 707 struct inpcb *inp = tp->t_inpcb; 708 struct socket *so = inp->inp_socket; 709 #ifdef INET6 710 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 711 #endif /* INET6 */ 712 713 INP_WLOCK_ASSERT(inp); 714 715 /* 716 * Make sure that all of our timers are stopped before we 717 * delete the PCB. 718 */ 719 callout_stop(&tp->t_timers->tt_rexmt); 720 callout_stop(&tp->t_timers->tt_persist); 721 callout_stop(&tp->t_timers->tt_keep); 722 callout_stop(&tp->t_timers->tt_2msl); 723 callout_stop(&tp->t_timers->tt_delack); 724 725 /* 726 * If we got enough samples through the srtt filter, 727 * save the rtt and rttvar in the routing entry. 728 * 'Enough' is arbitrarily defined as 4 rtt samples. 729 * 4 samples is enough for the srtt filter to converge 730 * to within enough % of the correct value; fewer samples 731 * and we could save a bogus rtt. The danger is not high 732 * as tcp quickly recovers from everything. 733 * XXX: Works very well but needs some more statistics! 734 */ 735 if (tp->t_rttupdated >= 4) { 736 struct hc_metrics_lite metrics; 737 u_long ssthresh; 738 739 bzero(&metrics, sizeof(metrics)); 740 /* 741 * Update the ssthresh always when the conditions below 742 * are satisfied. This gives us better new start value 743 * for the congestion avoidance for new connections. 744 * ssthresh is only set if packet loss occured on a session. 745 * 746 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 747 * being torn down. Ideally this code would not use 'so'. 748 */ 749 ssthresh = tp->snd_ssthresh; 750 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 751 /* 752 * convert the limit from user data bytes to 753 * packets then to packet data bytes. 754 */ 755 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 756 if (ssthresh < 2) 757 ssthresh = 2; 758 ssthresh *= (u_long)(tp->t_maxseg + 759 #ifdef INET6 760 (isipv6 ? sizeof (struct ip6_hdr) + 761 sizeof (struct tcphdr) : 762 #endif 763 sizeof (struct tcpiphdr) 764 #ifdef INET6 765 ) 766 #endif 767 ); 768 } else 769 ssthresh = 0; 770 metrics.rmx_ssthresh = ssthresh; 771 772 metrics.rmx_rtt = tp->t_srtt; 773 metrics.rmx_rttvar = tp->t_rttvar; 774 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 775 metrics.rmx_bandwidth = tp->snd_bandwidth; 776 metrics.rmx_cwnd = tp->snd_cwnd; 777 metrics.rmx_sendpipe = 0; 778 metrics.rmx_recvpipe = 0; 779 780 tcp_hc_update(&inp->inp_inc, &metrics); 781 } 782 783 /* free the reassembly queue, if any */ 784 tcp_reass_flush(tp); 785 /* Disconnect offload device, if any. */ 786 tcp_offload_detach(tp); 787 788 tcp_free_sackholes(tp); 789 inp->inp_ppcb = NULL; 790 tp->t_inpcb = NULL; 791 uma_zfree(tcpcb_zone, tp); 792 } 793 794 /* 795 * Attempt to close a TCP control block, marking it as dropped, and freeing 796 * the socket if we hold the only reference. 797 */ 798 struct tcpcb * 799 tcp_close(struct tcpcb *tp) 800 { 801 struct inpcb *inp = tp->t_inpcb; 802 struct socket *so; 803 804 INP_INFO_WLOCK_ASSERT(&tcbinfo); 805 INP_WLOCK_ASSERT(inp); 806 807 /* Notify any offload devices of listener close */ 808 if (tp->t_state == TCPS_LISTEN) 809 tcp_offload_listen_close(tp); 810 in_pcbdrop(inp); 811 tcpstat.tcps_closed++; 812 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 813 so = inp->inp_socket; 814 soisdisconnected(so); 815 if (inp->inp_flags & INP_SOCKREF) { 816 KASSERT(so->so_state & SS_PROTOREF, 817 ("tcp_close: !SS_PROTOREF")); 818 inp->inp_flags &= ~INP_SOCKREF; 819 INP_WUNLOCK(inp); 820 ACCEPT_LOCK(); 821 SOCK_LOCK(so); 822 so->so_state &= ~SS_PROTOREF; 823 sofree(so); 824 return (NULL); 825 } 826 return (tp); 827 } 828 829 void 830 tcp_drain(void) 831 { 832 833 if (do_tcpdrain) { 834 struct inpcb *inpb; 835 struct tcpcb *tcpb; 836 837 /* 838 * Walk the tcpbs, if existing, and flush the reassembly queue, 839 * if there is one... 840 * XXX: The "Net/3" implementation doesn't imply that the TCP 841 * reassembly queue should be flushed, but in a situation 842 * where we're really low on mbufs, this is potentially 843 * usefull. 844 */ 845 INP_INFO_RLOCK(&tcbinfo); 846 LIST_FOREACH(inpb, tcbinfo.ipi_listhead, inp_list) { 847 if (inpb->inp_flags & INP_TIMEWAIT) 848 continue; 849 INP_WLOCK(inpb); 850 if ((tcpb = intotcpcb(inpb)) != NULL) { 851 tcp_reass_flush(tcpb); 852 tcp_clean_sackreport(tcpb); 853 } 854 INP_WUNLOCK(inpb); 855 } 856 INP_INFO_RUNLOCK(&tcbinfo); 857 } 858 } 859 860 /* 861 * Notify a tcp user of an asynchronous error; 862 * store error as soft error, but wake up user 863 * (for now, won't do anything until can select for soft error). 864 * 865 * Do not wake up user since there currently is no mechanism for 866 * reporting soft errors (yet - a kqueue filter may be added). 867 */ 868 static struct inpcb * 869 tcp_notify(struct inpcb *inp, int error) 870 { 871 struct tcpcb *tp; 872 873 INP_INFO_WLOCK_ASSERT(&tcbinfo); 874 INP_WLOCK_ASSERT(inp); 875 876 if ((inp->inp_flags & INP_TIMEWAIT) || 877 (inp->inp_flags & INP_DROPPED)) 878 return (inp); 879 880 tp = intotcpcb(inp); 881 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 882 883 /* 884 * Ignore some errors if we are hooked up. 885 * If connection hasn't completed, has retransmitted several times, 886 * and receives a second error, give up now. This is better 887 * than waiting a long time to establish a connection that 888 * can never complete. 889 */ 890 if (tp->t_state == TCPS_ESTABLISHED && 891 (error == EHOSTUNREACH || error == ENETUNREACH || 892 error == EHOSTDOWN)) { 893 return (inp); 894 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 895 tp->t_softerror) { 896 tp = tcp_drop(tp, error); 897 if (tp != NULL) 898 return (inp); 899 else 900 return (NULL); 901 } else { 902 tp->t_softerror = error; 903 return (inp); 904 } 905 #if 0 906 wakeup( &so->so_timeo); 907 sorwakeup(so); 908 sowwakeup(so); 909 #endif 910 } 911 912 static int 913 tcp_pcblist(SYSCTL_HANDLER_ARGS) 914 { 915 int error, i, m, n, pcb_count; 916 struct inpcb *inp, **inp_list; 917 inp_gen_t gencnt; 918 struct xinpgen xig; 919 920 /* 921 * The process of preparing the TCB list is too time-consuming and 922 * resource-intensive to repeat twice on every request. 923 */ 924 if (req->oldptr == NULL) { 925 n = tcbinfo.ipi_count + syncache_pcbcount(); 926 n += imax(n / 8, 10); 927 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb); 928 return (0); 929 } 930 931 if (req->newptr != NULL) 932 return (EPERM); 933 934 /* 935 * OK, now we're committed to doing something. 936 */ 937 INP_INFO_RLOCK(&tcbinfo); 938 gencnt = tcbinfo.ipi_gencnt; 939 n = tcbinfo.ipi_count; 940 INP_INFO_RUNLOCK(&tcbinfo); 941 942 m = syncache_pcbcount(); 943 944 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 945 + (n + m) * sizeof(struct xtcpcb)); 946 if (error != 0) 947 return (error); 948 949 xig.xig_len = sizeof xig; 950 xig.xig_count = n + m; 951 xig.xig_gen = gencnt; 952 xig.xig_sogen = so_gencnt; 953 error = SYSCTL_OUT(req, &xig, sizeof xig); 954 if (error) 955 return (error); 956 957 error = syncache_pcblist(req, m, &pcb_count); 958 if (error) 959 return (error); 960 961 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 962 if (inp_list == NULL) 963 return (ENOMEM); 964 965 INP_INFO_RLOCK(&tcbinfo); 966 for (inp = LIST_FIRST(tcbinfo.ipi_listhead), i = 0; inp != NULL && i 967 < n; inp = LIST_NEXT(inp, inp_list)) { 968 INP_RLOCK(inp); 969 if (inp->inp_gencnt <= gencnt) { 970 /* 971 * XXX: This use of cr_cansee(), introduced with 972 * TCP state changes, is not quite right, but for 973 * now, better than nothing. 974 */ 975 if (inp->inp_flags & INP_TIMEWAIT) { 976 if (intotw(inp) != NULL) 977 error = cr_cansee(req->td->td_ucred, 978 intotw(inp)->tw_cred); 979 else 980 error = EINVAL; /* Skip this inp. */ 981 } else 982 error = cr_canseeinpcb(req->td->td_ucred, inp); 983 if (error == 0) 984 inp_list[i++] = inp; 985 } 986 INP_RUNLOCK(inp); 987 } 988 INP_INFO_RUNLOCK(&tcbinfo); 989 n = i; 990 991 error = 0; 992 for (i = 0; i < n; i++) { 993 inp = inp_list[i]; 994 INP_RLOCK(inp); 995 if (inp->inp_gencnt <= gencnt) { 996 struct xtcpcb xt; 997 void *inp_ppcb; 998 999 bzero(&xt, sizeof(xt)); 1000 xt.xt_len = sizeof xt; 1001 /* XXX should avoid extra copy */ 1002 bcopy(inp, &xt.xt_inp, sizeof *inp); 1003 inp_ppcb = inp->inp_ppcb; 1004 if (inp_ppcb == NULL) 1005 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1006 else if (inp->inp_flags & INP_TIMEWAIT) { 1007 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1008 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1009 } else 1010 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1011 if (inp->inp_socket != NULL) 1012 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1013 else { 1014 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1015 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1016 } 1017 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1018 INP_RUNLOCK(inp); 1019 error = SYSCTL_OUT(req, &xt, sizeof xt); 1020 } else 1021 INP_RUNLOCK(inp); 1022 1023 } 1024 if (!error) { 1025 /* 1026 * Give the user an updated idea of our state. 1027 * If the generation differs from what we told 1028 * her before, she knows that something happened 1029 * while we were processing this request, and it 1030 * might be necessary to retry. 1031 */ 1032 INP_INFO_RLOCK(&tcbinfo); 1033 xig.xig_gen = tcbinfo.ipi_gencnt; 1034 xig.xig_sogen = so_gencnt; 1035 xig.xig_count = tcbinfo.ipi_count + pcb_count; 1036 INP_INFO_RUNLOCK(&tcbinfo); 1037 error = SYSCTL_OUT(req, &xig, sizeof xig); 1038 } 1039 free(inp_list, M_TEMP); 1040 return (error); 1041 } 1042 1043 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1044 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1045 1046 static int 1047 tcp_getcred(SYSCTL_HANDLER_ARGS) 1048 { 1049 struct xucred xuc; 1050 struct sockaddr_in addrs[2]; 1051 struct inpcb *inp; 1052 int error; 1053 1054 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1055 if (error) 1056 return (error); 1057 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1058 if (error) 1059 return (error); 1060 INP_INFO_RLOCK(&tcbinfo); 1061 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 1062 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1063 if (inp != NULL) { 1064 INP_RLOCK(inp); 1065 INP_INFO_RUNLOCK(&tcbinfo); 1066 if (inp->inp_socket == NULL) 1067 error = ENOENT; 1068 if (error == 0) 1069 error = cr_canseeinpcb(req->td->td_ucred, inp); 1070 if (error == 0) 1071 cru2x(inp->inp_cred, &xuc); 1072 INP_RUNLOCK(inp); 1073 } else { 1074 INP_INFO_RUNLOCK(&tcbinfo); 1075 error = ENOENT; 1076 } 1077 if (error == 0) 1078 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1079 return (error); 1080 } 1081 1082 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1083 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1084 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1085 1086 #ifdef INET6 1087 static int 1088 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1089 { 1090 struct xucred xuc; 1091 struct sockaddr_in6 addrs[2]; 1092 struct inpcb *inp; 1093 int error, mapped = 0; 1094 1095 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1096 if (error) 1097 return (error); 1098 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1099 if (error) 1100 return (error); 1101 if ((error = sa6_embedscope(&addrs[0], ip6_use_defzone)) != 0 || 1102 (error = sa6_embedscope(&addrs[1], ip6_use_defzone)) != 0) { 1103 return (error); 1104 } 1105 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1106 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1107 mapped = 1; 1108 else 1109 return (EINVAL); 1110 } 1111 1112 INP_INFO_RLOCK(&tcbinfo); 1113 if (mapped == 1) 1114 inp = in_pcblookup_hash(&tcbinfo, 1115 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1116 addrs[1].sin6_port, 1117 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1118 addrs[0].sin6_port, 1119 0, NULL); 1120 else 1121 inp = in6_pcblookup_hash(&tcbinfo, 1122 &addrs[1].sin6_addr, addrs[1].sin6_port, 1123 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1124 if (inp != NULL) { 1125 INP_RLOCK(inp); 1126 INP_INFO_RUNLOCK(&tcbinfo); 1127 if (inp->inp_socket == NULL) 1128 error = ENOENT; 1129 if (error == 0) 1130 error = cr_canseeinpcb(req->td->td_ucred, inp); 1131 if (error == 0) 1132 cru2x(inp->inp_cred, &xuc); 1133 INP_RUNLOCK(inp); 1134 } else { 1135 INP_INFO_RUNLOCK(&tcbinfo); 1136 error = ENOENT; 1137 } 1138 if (error == 0) 1139 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1140 return (error); 1141 } 1142 1143 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1144 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1145 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1146 #endif 1147 1148 1149 void 1150 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1151 { 1152 struct ip *ip = vip; 1153 struct tcphdr *th; 1154 struct in_addr faddr; 1155 struct inpcb *inp; 1156 struct tcpcb *tp; 1157 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1158 struct icmp *icp; 1159 struct in_conninfo inc; 1160 tcp_seq icmp_tcp_seq; 1161 int mtu; 1162 1163 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1164 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1165 return; 1166 1167 if (cmd == PRC_MSGSIZE) 1168 notify = tcp_mtudisc; 1169 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1170 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1171 notify = tcp_drop_syn_sent; 1172 /* 1173 * Redirects don't need to be handled up here. 1174 */ 1175 else if (PRC_IS_REDIRECT(cmd)) 1176 return; 1177 /* 1178 * Source quench is depreciated. 1179 */ 1180 else if (cmd == PRC_QUENCH) 1181 return; 1182 /* 1183 * Hostdead is ugly because it goes linearly through all PCBs. 1184 * XXX: We never get this from ICMP, otherwise it makes an 1185 * excellent DoS attack on machines with many connections. 1186 */ 1187 else if (cmd == PRC_HOSTDEAD) 1188 ip = NULL; 1189 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1190 return; 1191 if (ip != NULL) { 1192 icp = (struct icmp *)((caddr_t)ip 1193 - offsetof(struct icmp, icmp_ip)); 1194 th = (struct tcphdr *)((caddr_t)ip 1195 + (ip->ip_hl << 2)); 1196 INP_INFO_WLOCK(&tcbinfo); 1197 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1198 ip->ip_src, th->th_sport, 0, NULL); 1199 if (inp != NULL) { 1200 INP_WLOCK(inp); 1201 if (!(inp->inp_flags & INP_TIMEWAIT) && 1202 !(inp->inp_flags & INP_DROPPED) && 1203 !(inp->inp_socket == NULL)) { 1204 icmp_tcp_seq = htonl(th->th_seq); 1205 tp = intotcpcb(inp); 1206 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1207 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1208 if (cmd == PRC_MSGSIZE) { 1209 /* 1210 * MTU discovery: 1211 * If we got a needfrag set the MTU 1212 * in the route to the suggested new 1213 * value (if given) and then notify. 1214 */ 1215 bzero(&inc, sizeof(inc)); 1216 inc.inc_faddr = faddr; 1217 inc.inc_fibnum = 1218 inp->inp_inc.inc_fibnum; 1219 1220 mtu = ntohs(icp->icmp_nextmtu); 1221 /* 1222 * If no alternative MTU was 1223 * proposed, try the next smaller 1224 * one. ip->ip_len has already 1225 * been swapped in icmp_input(). 1226 */ 1227 if (!mtu) 1228 mtu = ip_next_mtu(ip->ip_len, 1229 1); 1230 if (mtu < tcp_minmss 1231 + sizeof(struct tcpiphdr)) 1232 mtu = tcp_minmss 1233 + sizeof(struct tcpiphdr); 1234 /* 1235 * Only cache the the MTU if it 1236 * is smaller than the interface 1237 * or route MTU. tcp_mtudisc() 1238 * will do right thing by itself. 1239 */ 1240 if (mtu <= tcp_maxmtu(&inc, NULL)) 1241 tcp_hc_updatemtu(&inc, mtu); 1242 } 1243 1244 inp = (*notify)(inp, inetctlerrmap[cmd]); 1245 } 1246 } 1247 if (inp != NULL) 1248 INP_WUNLOCK(inp); 1249 } else { 1250 bzero(&inc, sizeof(inc)); 1251 inc.inc_fport = th->th_dport; 1252 inc.inc_lport = th->th_sport; 1253 inc.inc_faddr = faddr; 1254 inc.inc_laddr = ip->ip_src; 1255 syncache_unreach(&inc, th); 1256 } 1257 INP_INFO_WUNLOCK(&tcbinfo); 1258 } else 1259 in_pcbnotifyall(&tcbinfo, faddr, inetctlerrmap[cmd], notify); 1260 } 1261 1262 #ifdef INET6 1263 void 1264 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1265 { 1266 struct tcphdr th; 1267 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1268 struct ip6_hdr *ip6; 1269 struct mbuf *m; 1270 struct ip6ctlparam *ip6cp = NULL; 1271 const struct sockaddr_in6 *sa6_src = NULL; 1272 int off; 1273 struct tcp_portonly { 1274 u_int16_t th_sport; 1275 u_int16_t th_dport; 1276 } *thp; 1277 1278 if (sa->sa_family != AF_INET6 || 1279 sa->sa_len != sizeof(struct sockaddr_in6)) 1280 return; 1281 1282 if (cmd == PRC_MSGSIZE) 1283 notify = tcp_mtudisc; 1284 else if (!PRC_IS_REDIRECT(cmd) && 1285 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1286 return; 1287 /* Source quench is depreciated. */ 1288 else if (cmd == PRC_QUENCH) 1289 return; 1290 1291 /* if the parameter is from icmp6, decode it. */ 1292 if (d != NULL) { 1293 ip6cp = (struct ip6ctlparam *)d; 1294 m = ip6cp->ip6c_m; 1295 ip6 = ip6cp->ip6c_ip6; 1296 off = ip6cp->ip6c_off; 1297 sa6_src = ip6cp->ip6c_src; 1298 } else { 1299 m = NULL; 1300 ip6 = NULL; 1301 off = 0; /* fool gcc */ 1302 sa6_src = &sa6_any; 1303 } 1304 1305 if (ip6 != NULL) { 1306 struct in_conninfo inc; 1307 /* 1308 * XXX: We assume that when IPV6 is non NULL, 1309 * M and OFF are valid. 1310 */ 1311 1312 /* check if we can safely examine src and dst ports */ 1313 if (m->m_pkthdr.len < off + sizeof(*thp)) 1314 return; 1315 1316 bzero(&th, sizeof(th)); 1317 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1318 1319 in6_pcbnotify(&tcbinfo, sa, th.th_dport, 1320 (struct sockaddr *)ip6cp->ip6c_src, 1321 th.th_sport, cmd, NULL, notify); 1322 1323 bzero(&inc, sizeof(inc)); 1324 inc.inc_fport = th.th_dport; 1325 inc.inc_lport = th.th_sport; 1326 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1327 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1328 inc.inc_flags |= INC_ISIPV6; 1329 INP_INFO_WLOCK(&tcbinfo); 1330 syncache_unreach(&inc, &th); 1331 INP_INFO_WUNLOCK(&tcbinfo); 1332 } else 1333 in6_pcbnotify(&tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1334 0, cmd, NULL, notify); 1335 } 1336 #endif /* INET6 */ 1337 1338 1339 /* 1340 * Following is where TCP initial sequence number generation occurs. 1341 * 1342 * There are two places where we must use initial sequence numbers: 1343 * 1. In SYN-ACK packets. 1344 * 2. In SYN packets. 1345 * 1346 * All ISNs for SYN-ACK packets are generated by the syncache. See 1347 * tcp_syncache.c for details. 1348 * 1349 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1350 * depends on this property. In addition, these ISNs should be 1351 * unguessable so as to prevent connection hijacking. To satisfy 1352 * the requirements of this situation, the algorithm outlined in 1353 * RFC 1948 is used, with only small modifications. 1354 * 1355 * Implementation details: 1356 * 1357 * Time is based off the system timer, and is corrected so that it 1358 * increases by one megabyte per second. This allows for proper 1359 * recycling on high speed LANs while still leaving over an hour 1360 * before rollover. 1361 * 1362 * As reading the *exact* system time is too expensive to be done 1363 * whenever setting up a TCP connection, we increment the time 1364 * offset in two ways. First, a small random positive increment 1365 * is added to isn_offset for each connection that is set up. 1366 * Second, the function tcp_isn_tick fires once per clock tick 1367 * and increments isn_offset as necessary so that sequence numbers 1368 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1369 * random positive increments serve only to ensure that the same 1370 * exact sequence number is never sent out twice (as could otherwise 1371 * happen when a port is recycled in less than the system tick 1372 * interval.) 1373 * 1374 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1375 * between seeding of isn_secret. This is normally set to zero, 1376 * as reseeding should not be necessary. 1377 * 1378 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1379 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1380 * general, this means holding an exclusive (write) lock. 1381 */ 1382 1383 #define ISN_BYTES_PER_SECOND 1048576 1384 #define ISN_STATIC_INCREMENT 4096 1385 #define ISN_RANDOM_INCREMENT (4096 - 1) 1386 1387 static u_char isn_secret[32]; 1388 static int isn_last_reseed; 1389 static u_int32_t isn_offset, isn_offset_old; 1390 static MD5_CTX isn_ctx; 1391 1392 tcp_seq 1393 tcp_new_isn(struct tcpcb *tp) 1394 { 1395 u_int32_t md5_buffer[4]; 1396 tcp_seq new_isn; 1397 1398 INP_WLOCK_ASSERT(tp->t_inpcb); 1399 1400 ISN_LOCK(); 1401 /* Seed if this is the first use, reseed if requested. */ 1402 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1403 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1404 < (u_int)ticks))) { 1405 read_random(&isn_secret, sizeof(isn_secret)); 1406 isn_last_reseed = ticks; 1407 } 1408 1409 /* Compute the md5 hash and return the ISN. */ 1410 MD5Init(&isn_ctx); 1411 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1412 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1413 #ifdef INET6 1414 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1415 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1416 sizeof(struct in6_addr)); 1417 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1418 sizeof(struct in6_addr)); 1419 } else 1420 #endif 1421 { 1422 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1423 sizeof(struct in_addr)); 1424 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1425 sizeof(struct in_addr)); 1426 } 1427 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1428 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1429 new_isn = (tcp_seq) md5_buffer[0]; 1430 isn_offset += ISN_STATIC_INCREMENT + 1431 (arc4random() & ISN_RANDOM_INCREMENT); 1432 new_isn += isn_offset; 1433 ISN_UNLOCK(); 1434 return (new_isn); 1435 } 1436 1437 /* 1438 * Increment the offset to the next ISN_BYTES_PER_SECOND / 100 boundary 1439 * to keep time flowing at a relatively constant rate. If the random 1440 * increments have already pushed us past the projected offset, do nothing. 1441 */ 1442 static void 1443 tcp_isn_tick(void *xtp) 1444 { 1445 u_int32_t projected_offset; 1446 1447 ISN_LOCK(); 1448 projected_offset = isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1449 1450 if (SEQ_GT(projected_offset, isn_offset)) 1451 isn_offset = projected_offset; 1452 1453 isn_offset_old = isn_offset; 1454 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1455 ISN_UNLOCK(); 1456 } 1457 1458 /* 1459 * When a specific ICMP unreachable message is received and the 1460 * connection state is SYN-SENT, drop the connection. This behavior 1461 * is controlled by the icmp_may_rst sysctl. 1462 */ 1463 struct inpcb * 1464 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1465 { 1466 struct tcpcb *tp; 1467 1468 INP_INFO_WLOCK_ASSERT(&tcbinfo); 1469 INP_WLOCK_ASSERT(inp); 1470 1471 if ((inp->inp_flags & INP_TIMEWAIT) || 1472 (inp->inp_flags & INP_DROPPED)) 1473 return (inp); 1474 1475 tp = intotcpcb(inp); 1476 if (tp->t_state != TCPS_SYN_SENT) 1477 return (inp); 1478 1479 tp = tcp_drop(tp, errno); 1480 if (tp != NULL) 1481 return (inp); 1482 else 1483 return (NULL); 1484 } 1485 1486 /* 1487 * When `need fragmentation' ICMP is received, update our idea of the MSS 1488 * based on the new value in the route. Also nudge TCP to send something, 1489 * since we know the packet we just sent was dropped. 1490 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1491 */ 1492 struct inpcb * 1493 tcp_mtudisc(struct inpcb *inp, int errno) 1494 { 1495 struct tcpcb *tp; 1496 struct socket *so; 1497 1498 INP_WLOCK_ASSERT(inp); 1499 if ((inp->inp_flags & INP_TIMEWAIT) || 1500 (inp->inp_flags & INP_DROPPED)) 1501 return (inp); 1502 1503 tp = intotcpcb(inp); 1504 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1505 1506 tcp_mss_update(tp, -1, NULL, NULL); 1507 1508 so = inp->inp_socket; 1509 SOCKBUF_LOCK(&so->so_snd); 1510 /* If the mss is larger than the socket buffer, decrease the mss. */ 1511 if (so->so_snd.sb_hiwat < tp->t_maxseg) 1512 tp->t_maxseg = so->so_snd.sb_hiwat; 1513 SOCKBUF_UNLOCK(&so->so_snd); 1514 1515 tcpstat.tcps_mturesent++; 1516 tp->t_rtttime = 0; 1517 tp->snd_nxt = tp->snd_una; 1518 tcp_free_sackholes(tp); 1519 tp->snd_recover = tp->snd_max; 1520 if (tp->t_flags & TF_SACK_PERMIT) 1521 EXIT_FASTRECOVERY(tp); 1522 tcp_output_send(tp); 1523 return (inp); 1524 } 1525 1526 /* 1527 * Look-up the routing entry to the peer of this inpcb. If no route 1528 * is found and it cannot be allocated, then return 0. This routine 1529 * is called by TCP routines that access the rmx structure and by 1530 * tcp_mss_update to get the peer/interface MTU. 1531 */ 1532 u_long 1533 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1534 { 1535 struct route sro; 1536 struct sockaddr_in *dst; 1537 struct ifnet *ifp; 1538 u_long maxmtu = 0; 1539 1540 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1541 1542 bzero(&sro, sizeof(sro)); 1543 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1544 dst = (struct sockaddr_in *)&sro.ro_dst; 1545 dst->sin_family = AF_INET; 1546 dst->sin_len = sizeof(*dst); 1547 dst->sin_addr = inc->inc_faddr; 1548 in_rtalloc_ign(&sro, RTF_CLONING, inc->inc_fibnum); 1549 } 1550 if (sro.ro_rt != NULL) { 1551 ifp = sro.ro_rt->rt_ifp; 1552 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1553 maxmtu = ifp->if_mtu; 1554 else 1555 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1556 1557 /* Report additional interface capabilities. */ 1558 if (flags != NULL) { 1559 if (ifp->if_capenable & IFCAP_TSO4 && 1560 ifp->if_hwassist & CSUM_TSO) 1561 *flags |= CSUM_TSO; 1562 } 1563 RTFREE(sro.ro_rt); 1564 } 1565 return (maxmtu); 1566 } 1567 1568 #ifdef INET6 1569 u_long 1570 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1571 { 1572 struct route_in6 sro6; 1573 struct ifnet *ifp; 1574 u_long maxmtu = 0; 1575 1576 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1577 1578 bzero(&sro6, sizeof(sro6)); 1579 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1580 sro6.ro_dst.sin6_family = AF_INET6; 1581 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1582 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1583 rtalloc_ign((struct route *)&sro6, RTF_CLONING); 1584 } 1585 if (sro6.ro_rt != NULL) { 1586 ifp = sro6.ro_rt->rt_ifp; 1587 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1588 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1589 else 1590 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1591 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1592 1593 /* Report additional interface capabilities. */ 1594 if (flags != NULL) { 1595 if (ifp->if_capenable & IFCAP_TSO6 && 1596 ifp->if_hwassist & CSUM_TSO) 1597 *flags |= CSUM_TSO; 1598 } 1599 RTFREE(sro6.ro_rt); 1600 } 1601 1602 return (maxmtu); 1603 } 1604 #endif /* INET6 */ 1605 1606 #ifdef IPSEC 1607 /* compute ESP/AH header size for TCP, including outer IP header. */ 1608 size_t 1609 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1610 { 1611 struct inpcb *inp; 1612 struct mbuf *m; 1613 size_t hdrsiz; 1614 struct ip *ip; 1615 #ifdef INET6 1616 struct ip6_hdr *ip6; 1617 #endif 1618 struct tcphdr *th; 1619 1620 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1621 return (0); 1622 MGETHDR(m, M_DONTWAIT, MT_DATA); 1623 if (!m) 1624 return (0); 1625 1626 #ifdef INET6 1627 if ((inp->inp_vflag & INP_IPV6) != 0) { 1628 ip6 = mtod(m, struct ip6_hdr *); 1629 th = (struct tcphdr *)(ip6 + 1); 1630 m->m_pkthdr.len = m->m_len = 1631 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1632 tcpip_fillheaders(inp, ip6, th); 1633 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1634 } else 1635 #endif /* INET6 */ 1636 { 1637 ip = mtod(m, struct ip *); 1638 th = (struct tcphdr *)(ip + 1); 1639 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1640 tcpip_fillheaders(inp, ip, th); 1641 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1642 } 1643 1644 m_free(m); 1645 return (hdrsiz); 1646 } 1647 #endif /* IPSEC */ 1648 1649 /* 1650 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1651 * 1652 * This code attempts to calculate the bandwidth-delay product as a 1653 * means of determining the optimal window size to maximize bandwidth, 1654 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1655 * routers. This code also does a fairly good job keeping RTTs in check 1656 * across slow links like modems. We implement an algorithm which is very 1657 * similar (but not meant to be) TCP/Vegas. The code operates on the 1658 * transmitter side of a TCP connection and so only effects the transmit 1659 * side of the connection. 1660 * 1661 * BACKGROUND: TCP makes no provision for the management of buffer space 1662 * at the end points or at the intermediate routers and switches. A TCP 1663 * stream, whether using NewReno or not, will eventually buffer as 1664 * many packets as it is able and the only reason this typically works is 1665 * due to the fairly small default buffers made available for a connection 1666 * (typicaly 16K or 32K). As machines use larger windows and/or window 1667 * scaling it is now fairly easy for even a single TCP connection to blow-out 1668 * all available buffer space not only on the local interface, but on 1669 * intermediate routers and switches as well. NewReno makes a misguided 1670 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1671 * then backing off, then steadily increasing the window again until another 1672 * failure occurs, ad-infinitum. This results in terrible oscillation that 1673 * is only made worse as network loads increase and the idea of intentionally 1674 * blowing out network buffers is, frankly, a terrible way to manage network 1675 * resources. 1676 * 1677 * It is far better to limit the transmit window prior to the failure 1678 * condition being achieved. There are two general ways to do this: First 1679 * you can 'scan' through different transmit window sizes and locate the 1680 * point where the RTT stops increasing, indicating that you have filled the 1681 * pipe, then scan backwards until you note that RTT stops decreasing, then 1682 * repeat ad-infinitum. This method works in principle but has severe 1683 * implementation issues due to RTT variances, timer granularity, and 1684 * instability in the algorithm which can lead to many false positives and 1685 * create oscillations as well as interact badly with other TCP streams 1686 * implementing the same algorithm. 1687 * 1688 * The second method is to limit the window to the bandwidth delay product 1689 * of the link. This is the method we implement. RTT variances and our 1690 * own manipulation of the congestion window, bwnd, can potentially 1691 * destabilize the algorithm. For this reason we have to stabilize the 1692 * elements used to calculate the window. We do this by using the minimum 1693 * observed RTT, the long term average of the observed bandwidth, and 1694 * by adding two segments worth of slop. It isn't perfect but it is able 1695 * to react to changing conditions and gives us a very stable basis on 1696 * which to extend the algorithm. 1697 */ 1698 void 1699 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1700 { 1701 u_long bw; 1702 u_long bwnd; 1703 int save_ticks; 1704 1705 INP_WLOCK_ASSERT(tp->t_inpcb); 1706 1707 /* 1708 * If inflight_enable is disabled in the middle of a tcp connection, 1709 * make sure snd_bwnd is effectively disabled. 1710 */ 1711 if (tcp_inflight_enable == 0 || tp->t_rttlow < tcp_inflight_rttthresh) { 1712 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1713 tp->snd_bandwidth = 0; 1714 return; 1715 } 1716 1717 /* 1718 * Figure out the bandwidth. Due to the tick granularity this 1719 * is a very rough number and it MUST be averaged over a fairly 1720 * long period of time. XXX we need to take into account a link 1721 * that is not using all available bandwidth, but for now our 1722 * slop will ramp us up if this case occurs and the bandwidth later 1723 * increases. 1724 * 1725 * Note: if ticks rollover 'bw' may wind up negative. We must 1726 * effectively reset t_bw_rtttime for this case. 1727 */ 1728 save_ticks = ticks; 1729 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 1730 return; 1731 1732 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 1733 (save_ticks - tp->t_bw_rtttime); 1734 tp->t_bw_rtttime = save_ticks; 1735 tp->t_bw_rtseq = ack_seq; 1736 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 1737 return; 1738 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1739 1740 tp->snd_bandwidth = bw; 1741 1742 /* 1743 * Calculate the semi-static bandwidth delay product, plus two maximal 1744 * segments. The additional slop puts us squarely in the sweet 1745 * spot and also handles the bandwidth run-up case and stabilization. 1746 * Without the slop we could be locking ourselves into a lower 1747 * bandwidth. 1748 * 1749 * Situations Handled: 1750 * (1) Prevents over-queueing of packets on LANs, especially on 1751 * high speed LANs, allowing larger TCP buffers to be 1752 * specified, and also does a good job preventing 1753 * over-queueing of packets over choke points like modems 1754 * (at least for the transmit side). 1755 * 1756 * (2) Is able to handle changing network loads (bandwidth 1757 * drops so bwnd drops, bandwidth increases so bwnd 1758 * increases). 1759 * 1760 * (3) Theoretically should stabilize in the face of multiple 1761 * connections implementing the same algorithm (this may need 1762 * a little work). 1763 * 1764 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1765 * be adjusted with a sysctl but typically only needs to be 1766 * on very slow connections. A value no smaller then 5 1767 * should be used, but only reduce this default if you have 1768 * no other choice. 1769 */ 1770 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1771 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + tcp_inflight_stab * tp->t_maxseg / 10; 1772 #undef USERTT 1773 1774 if (tcp_inflight_debug > 0) { 1775 static int ltime; 1776 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1777 ltime = ticks; 1778 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1779 tp, 1780 bw, 1781 tp->t_rttbest, 1782 tp->t_srtt, 1783 bwnd 1784 ); 1785 } 1786 } 1787 if ((long)bwnd < tcp_inflight_min) 1788 bwnd = tcp_inflight_min; 1789 if (bwnd > tcp_inflight_max) 1790 bwnd = tcp_inflight_max; 1791 if ((long)bwnd < tp->t_maxseg * 2) 1792 bwnd = tp->t_maxseg * 2; 1793 tp->snd_bwnd = bwnd; 1794 } 1795 1796 #ifdef TCP_SIGNATURE 1797 /* 1798 * Callback function invoked by m_apply() to digest TCP segment data 1799 * contained within an mbuf chain. 1800 */ 1801 static int 1802 tcp_signature_apply(void *fstate, void *data, u_int len) 1803 { 1804 1805 MD5Update(fstate, (u_char *)data, len); 1806 return (0); 1807 } 1808 1809 /* 1810 * Compute TCP-MD5 hash of a TCP segment. (RFC2385) 1811 * 1812 * Parameters: 1813 * m pointer to head of mbuf chain 1814 * _unused 1815 * len length of TCP segment data, excluding options 1816 * optlen length of TCP segment options 1817 * buf pointer to storage for computed MD5 digest 1818 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 1819 * 1820 * We do this over ip, tcphdr, segment data, and the key in the SADB. 1821 * When called from tcp_input(), we can be sure that th_sum has been 1822 * zeroed out and verified already. 1823 * 1824 * Return 0 if successful, otherwise return -1. 1825 * 1826 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 1827 * search with the destination IP address, and a 'magic SPI' to be 1828 * determined by the application. This is hardcoded elsewhere to 1179 1829 * right now. Another branch of this code exists which uses the SPD to 1830 * specify per-application flows but it is unstable. 1831 */ 1832 int 1833 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen, 1834 u_char *buf, u_int direction) 1835 { 1836 union sockaddr_union dst; 1837 struct ippseudo ippseudo; 1838 MD5_CTX ctx; 1839 int doff; 1840 struct ip *ip; 1841 struct ipovly *ipovly; 1842 struct secasvar *sav; 1843 struct tcphdr *th; 1844 #ifdef INET6 1845 struct ip6_hdr *ip6; 1846 struct in6_addr in6; 1847 char ip6buf[INET6_ADDRSTRLEN]; 1848 uint32_t plen; 1849 uint16_t nhdr; 1850 #endif 1851 u_short savecsum; 1852 1853 KASSERT(m != NULL, ("NULL mbuf chain")); 1854 KASSERT(buf != NULL, ("NULL signature pointer")); 1855 1856 /* Extract the destination from the IP header in the mbuf. */ 1857 bzero(&dst, sizeof(union sockaddr_union)); 1858 ip = mtod(m, struct ip *); 1859 #ifdef INET6 1860 ip6 = NULL; /* Make the compiler happy. */ 1861 #endif 1862 switch (ip->ip_v) { 1863 case IPVERSION: 1864 dst.sa.sa_len = sizeof(struct sockaddr_in); 1865 dst.sa.sa_family = AF_INET; 1866 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 1867 ip->ip_src : ip->ip_dst; 1868 break; 1869 #ifdef INET6 1870 case (IPV6_VERSION >> 4): 1871 ip6 = mtod(m, struct ip6_hdr *); 1872 dst.sa.sa_len = sizeof(struct sockaddr_in6); 1873 dst.sa.sa_family = AF_INET6; 1874 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ? 1875 ip6->ip6_src : ip6->ip6_dst; 1876 break; 1877 #endif 1878 default: 1879 return (EINVAL); 1880 /* NOTREACHED */ 1881 break; 1882 } 1883 1884 /* Look up an SADB entry which matches the address of the peer. */ 1885 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 1886 if (sav == NULL) { 1887 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__, 1888 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) : 1889 #ifdef INET6 1890 (ip->ip_v == (IPV6_VERSION >> 4)) ? 1891 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) : 1892 #endif 1893 "(unsupported)")); 1894 return (EINVAL); 1895 } 1896 1897 MD5Init(&ctx); 1898 /* 1899 * Step 1: Update MD5 hash with IP(v6) pseudo-header. 1900 * 1901 * XXX The ippseudo header MUST be digested in network byte order, 1902 * or else we'll fail the regression test. Assume all fields we've 1903 * been doing arithmetic on have been in host byte order. 1904 * XXX One cannot depend on ipovly->ih_len here. When called from 1905 * tcp_output(), the underlying ip_len member has not yet been set. 1906 */ 1907 switch (ip->ip_v) { 1908 case IPVERSION: 1909 ipovly = (struct ipovly *)ip; 1910 ippseudo.ippseudo_src = ipovly->ih_src; 1911 ippseudo.ippseudo_dst = ipovly->ih_dst; 1912 ippseudo.ippseudo_pad = 0; 1913 ippseudo.ippseudo_p = IPPROTO_TCP; 1914 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + 1915 optlen); 1916 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 1917 1918 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip)); 1919 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen; 1920 break; 1921 #ifdef INET6 1922 /* 1923 * RFC 2385, 2.0 Proposal 1924 * For IPv6, the pseudo-header is as described in RFC 2460, namely the 1925 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero- 1926 * extended next header value (to form 32 bits), and 32-bit segment 1927 * length. 1928 * Note: Upper-Layer Packet Length comes before Next Header. 1929 */ 1930 case (IPV6_VERSION >> 4): 1931 in6 = ip6->ip6_src; 1932 in6_clearscope(&in6); 1933 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 1934 in6 = ip6->ip6_dst; 1935 in6_clearscope(&in6); 1936 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 1937 plen = htonl(len + sizeof(struct tcphdr) + optlen); 1938 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t)); 1939 nhdr = 0; 1940 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 1941 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 1942 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 1943 nhdr = IPPROTO_TCP; 1944 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 1945 1946 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr)); 1947 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen; 1948 break; 1949 #endif 1950 default: 1951 return (EINVAL); 1952 /* NOTREACHED */ 1953 break; 1954 } 1955 1956 1957 /* 1958 * Step 2: Update MD5 hash with TCP header, excluding options. 1959 * The TCP checksum must be set to zero. 1960 */ 1961 savecsum = th->th_sum; 1962 th->th_sum = 0; 1963 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 1964 th->th_sum = savecsum; 1965 1966 /* 1967 * Step 3: Update MD5 hash with TCP segment data. 1968 * Use m_apply() to avoid an early m_pullup(). 1969 */ 1970 if (len > 0) 1971 m_apply(m, doff, len, tcp_signature_apply, &ctx); 1972 1973 /* 1974 * Step 4: Update MD5 hash with shared secret. 1975 */ 1976 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 1977 MD5Final(buf, &ctx); 1978 1979 key_sa_recordxfer(sav, m); 1980 KEY_FREESAV(&sav); 1981 return (0); 1982 } 1983 #endif /* TCP_SIGNATURE */ 1984 1985 static int 1986 sysctl_drop(SYSCTL_HANDLER_ARGS) 1987 { 1988 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 1989 struct sockaddr_storage addrs[2]; 1990 struct inpcb *inp; 1991 struct tcpcb *tp; 1992 struct tcptw *tw; 1993 struct sockaddr_in *fin, *lin; 1994 #ifdef INET6 1995 struct sockaddr_in6 *fin6, *lin6; 1996 struct in6_addr f6, l6; 1997 #endif 1998 int error; 1999 2000 inp = NULL; 2001 fin = lin = NULL; 2002 #ifdef INET6 2003 fin6 = lin6 = NULL; 2004 #endif 2005 error = 0; 2006 2007 if (req->oldptr != NULL || req->oldlen != 0) 2008 return (EINVAL); 2009 if (req->newptr == NULL) 2010 return (EPERM); 2011 if (req->newlen < sizeof(addrs)) 2012 return (ENOMEM); 2013 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2014 if (error) 2015 return (error); 2016 2017 switch (addrs[0].ss_family) { 2018 #ifdef INET6 2019 case AF_INET6: 2020 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2021 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2022 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2023 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2024 return (EINVAL); 2025 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2026 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2027 return (EINVAL); 2028 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2029 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2030 fin = (struct sockaddr_in *)&addrs[0]; 2031 lin = (struct sockaddr_in *)&addrs[1]; 2032 break; 2033 } 2034 error = sa6_embedscope(fin6, ip6_use_defzone); 2035 if (error) 2036 return (error); 2037 error = sa6_embedscope(lin6, ip6_use_defzone); 2038 if (error) 2039 return (error); 2040 break; 2041 #endif 2042 case AF_INET: 2043 fin = (struct sockaddr_in *)&addrs[0]; 2044 lin = (struct sockaddr_in *)&addrs[1]; 2045 if (fin->sin_len != sizeof(struct sockaddr_in) || 2046 lin->sin_len != sizeof(struct sockaddr_in)) 2047 return (EINVAL); 2048 break; 2049 default: 2050 return (EINVAL); 2051 } 2052 INP_INFO_WLOCK(&tcbinfo); 2053 switch (addrs[0].ss_family) { 2054 #ifdef INET6 2055 case AF_INET6: 2056 inp = in6_pcblookup_hash(&tcbinfo, &f6, fin6->sin6_port, 2057 &l6, lin6->sin6_port, 0, NULL); 2058 break; 2059 #endif 2060 case AF_INET: 2061 inp = in_pcblookup_hash(&tcbinfo, fin->sin_addr, fin->sin_port, 2062 lin->sin_addr, lin->sin_port, 0, NULL); 2063 break; 2064 } 2065 if (inp != NULL) { 2066 INP_WLOCK(inp); 2067 if (inp->inp_flags & INP_TIMEWAIT) { 2068 /* 2069 * XXXRW: There currently exists a state where an 2070 * inpcb is present, but its timewait state has been 2071 * discarded. For now, don't allow dropping of this 2072 * type of inpcb. 2073 */ 2074 tw = intotw(inp); 2075 if (tw != NULL) 2076 tcp_twclose(tw, 0); 2077 else 2078 INP_WUNLOCK(inp); 2079 } else if (!(inp->inp_flags & INP_DROPPED) && 2080 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2081 tp = intotcpcb(inp); 2082 tp = tcp_drop(tp, ECONNABORTED); 2083 if (tp != NULL) 2084 INP_WUNLOCK(inp); 2085 } else 2086 INP_WUNLOCK(inp); 2087 } else 2088 error = ESRCH; 2089 INP_INFO_WUNLOCK(&tcbinfo); 2090 return (error); 2091 } 2092 2093 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2094 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2095 0, sysctl_drop, "", "Drop TCP connection"); 2096 2097 /* 2098 * Generate a standardized TCP log line for use throughout the 2099 * tcp subsystem. Memory allocation is done with M_NOWAIT to 2100 * allow use in the interrupt context. 2101 * 2102 * NB: The caller MUST free(s, M_TCPLOG) the returned string. 2103 * NB: The function may return NULL if memory allocation failed. 2104 * 2105 * Due to header inclusion and ordering limitations the struct ip 2106 * and ip6_hdr pointers have to be passed as void pointers. 2107 */ 2108 char * 2109 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2110 const void *ip6hdr) 2111 { 2112 2113 /* Is logging enabled? */ 2114 if (tcp_log_in_vain == 0) 2115 return (NULL); 2116 2117 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr)); 2118 } 2119 2120 char * 2121 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2122 const void *ip6hdr) 2123 { 2124 2125 /* Is logging enabled? */ 2126 if (tcp_log_debug == 0) 2127 return (NULL); 2128 2129 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr)); 2130 } 2131 2132 static char * 2133 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2134 const void *ip6hdr) 2135 { 2136 char *s, *sp; 2137 size_t size; 2138 struct ip *ip; 2139 #ifdef INET6 2140 const struct ip6_hdr *ip6; 2141 2142 ip6 = (const struct ip6_hdr *)ip6hdr; 2143 #endif /* INET6 */ 2144 ip = (struct ip *)ip4hdr; 2145 2146 /* 2147 * The log line looks like this: 2148 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>" 2149 */ 2150 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") + 2151 sizeof(PRINT_TH_FLAGS) + 1 + 2152 #ifdef INET6 2153 2 * INET6_ADDRSTRLEN; 2154 #else 2155 2 * INET_ADDRSTRLEN; 2156 #endif /* INET6 */ 2157 2158 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT); 2159 if (s == NULL) 2160 return (NULL); 2161 2162 strcat(s, "TCP: ["); 2163 sp = s + strlen(s); 2164 2165 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) { 2166 inet_ntoa_r(inc->inc_faddr, sp); 2167 sp = s + strlen(s); 2168 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2169 sp = s + strlen(s); 2170 inet_ntoa_r(inc->inc_laddr, sp); 2171 sp = s + strlen(s); 2172 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2173 #ifdef INET6 2174 } else if (inc) { 2175 ip6_sprintf(sp, &inc->inc6_faddr); 2176 sp = s + strlen(s); 2177 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2178 sp = s + strlen(s); 2179 ip6_sprintf(sp, &inc->inc6_laddr); 2180 sp = s + strlen(s); 2181 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2182 } else if (ip6 && th) { 2183 ip6_sprintf(sp, &ip6->ip6_src); 2184 sp = s + strlen(s); 2185 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2186 sp = s + strlen(s); 2187 ip6_sprintf(sp, &ip6->ip6_dst); 2188 sp = s + strlen(s); 2189 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2190 #endif /* INET6 */ 2191 } else if (ip && th) { 2192 inet_ntoa_r(ip->ip_src, sp); 2193 sp = s + strlen(s); 2194 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2195 sp = s + strlen(s); 2196 inet_ntoa_r(ip->ip_dst, sp); 2197 sp = s + strlen(s); 2198 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2199 } else { 2200 free(s, M_TCPLOG); 2201 return (NULL); 2202 } 2203 sp = s + strlen(s); 2204 if (th) 2205 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS); 2206 if (*(s + size - 1) != '\0') 2207 panic("%s: string too long", __func__); 2208 return (s); 2209 }
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