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 * $FreeBSD$ 31 */ 32 33 #include "opt_compat.h" 34 #include "opt_inet.h" 35 #include "opt_inet6.h" 36 #include "opt_ipsec.h" 37 #include "opt_mac.h" 38 #include "opt_tcpdebug.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/callout.h> 43 #include <sys/kernel.h> 44 #include <sys/sysctl.h> 45 #include <sys/malloc.h> 46 #include <sys/mbuf.h> 47 #ifdef INET6 48 #include <sys/domain.h> 49 #endif 50 #include <sys/priv.h> 51 #include <sys/proc.h> 52 #include <sys/socket.h> 53 #include <sys/socketvar.h> 54 #include <sys/protosw.h> 55 #include <sys/random.h> 56 57 #include <vm/uma.h> 58 59 #include <net/route.h> 60 #include <net/if.h> 61 62 #include <netinet/in.h> 63 #include <netinet/in_systm.h> 64 #include <netinet/ip.h> 65 #ifdef INET6 66 #include <netinet/ip6.h> 67 #endif 68 #include <netinet/in_pcb.h> 69 #ifdef INET6 70 #include <netinet6/in6_pcb.h> 71 #endif 72 #include <netinet/in_var.h> 73 #include <netinet/ip_var.h> 74 #ifdef INET6 75 #include <netinet6/ip6_var.h> 76 #include <netinet6/scope6_var.h> 77 #include <netinet6/nd6.h> 78 #endif 79 #include <netinet/ip_icmp.h> 80 #include <netinet/tcp.h> 81 #include <netinet/tcp_fsm.h> 82 #include <netinet/tcp_seq.h> 83 #include <netinet/tcp_timer.h> 84 #include <netinet/tcp_var.h> 85 #ifdef INET6 86 #include <netinet6/tcp6_var.h> 87 #endif 88 #include <netinet/tcpip.h> 89 #ifdef TCPDEBUG 90 #include <netinet/tcp_debug.h> 91 #endif 92 #include <netinet6/ip6protosw.h> 93 94 #ifdef IPSEC 95 #include <netipsec/ipsec.h> 96 #include <netipsec/xform.h> 97 #ifdef INET6 98 #include <netipsec/ipsec6.h> 99 #endif 100 #include <netipsec/key.h> 101 #endif /*IPSEC*/ 102 103 #include <machine/in_cksum.h> 104 #include <sys/md5.h> 105 106 #include <security/mac/mac_framework.h> 107 108 int tcp_mssdflt = TCP_MSS; 109 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 110 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size"); 111 112 #ifdef INET6 113 int tcp_v6mssdflt = TCP6_MSS; 114 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 115 CTLFLAG_RW, &tcp_v6mssdflt , 0, 116 "Default TCP Maximum Segment Size for IPv6"); 117 #endif 118 119 /* 120 * Minimum MSS we accept and use. This prevents DoS attacks where 121 * we are forced to a ridiculous low MSS like 20 and send hundreds 122 * of packets instead of one. The effect scales with the available 123 * bandwidth and quickly saturates the CPU and network interface 124 * with packet generation and sending. Set to zero to disable MINMSS 125 * checking. This setting prevents us from sending too small packets. 126 */ 127 int tcp_minmss = TCP_MINMSS; 128 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 129 &tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 130 131 int tcp_do_rfc1323 = 1; 132 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 133 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions"); 134 135 static int tcp_tcbhashsize = 0; 136 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 137 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 138 139 static int do_tcpdrain = 1; 140 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, 141 &do_tcpdrain, 0, 142 "Enable tcp_drain routine for extra help when low on mbufs"); 143 144 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 145 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 146 147 static int icmp_may_rst = 1; 148 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, 149 &icmp_may_rst, 0, 150 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 151 152 static int tcp_isn_reseed_interval = 0; 153 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 154 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 155 156 /* 157 * TCP bandwidth limiting sysctls. Note that the default lower bound of 158 * 1024 exists only for debugging. A good production default would be 159 * something like 6100. 160 */ 161 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0, 162 "TCP inflight data limiting"); 163 164 static int tcp_inflight_enable = 1; 165 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, enable, CTLFLAG_RW, 166 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 167 168 static int tcp_inflight_debug = 0; 169 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW, 170 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 171 172 static int tcp_inflight_rttthresh; 173 SYSCTL_PROC(_net_inet_tcp_inflight, OID_AUTO, rttthresh, CTLTYPE_INT|CTLFLAG_RW, 174 &tcp_inflight_rttthresh, 0, sysctl_msec_to_ticks, "I", 175 "RTT threshold below which inflight will deactivate itself"); 176 177 static int tcp_inflight_min = 6144; 178 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, min, CTLFLAG_RW, 179 &tcp_inflight_min, 0, "Lower-bound for TCP inflight window"); 180 181 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 182 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, max, CTLFLAG_RW, 183 &tcp_inflight_max, 0, "Upper-bound for TCP inflight window"); 184 185 static int tcp_inflight_stab = 20; 186 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, stab, CTLFLAG_RW, 187 &tcp_inflight_stab, 0, "Inflight Algorithm Stabilization 20 = 2 packets"); 188 189 uma_zone_t sack_hole_zone; 190 191 static struct inpcb *tcp_notify(struct inpcb *, int); 192 static void tcp_isn_tick(void *); 193 194 /* 195 * Target size of TCP PCB hash tables. Must be a power of two. 196 * 197 * Note that this can be overridden by the kernel environment 198 * variable net.inet.tcp.tcbhashsize 199 */ 200 #ifndef TCBHASHSIZE 201 #define TCBHASHSIZE 512 202 #endif 203 204 /* 205 * XXX 206 * Callouts should be moved into struct tcp directly. They are currently 207 * separate because the tcpcb structure is exported to userland for sysctl 208 * parsing purposes, which do not know about callouts. 209 */ 210 struct tcpcb_mem { 211 struct tcpcb tcb; 212 struct tcp_timer tt; 213 }; 214 215 static uma_zone_t tcpcb_zone; 216 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers"); 217 struct callout isn_callout; 218 static struct mtx isn_mtx; 219 220 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 221 #define ISN_LOCK() mtx_lock(&isn_mtx) 222 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 223 224 /* 225 * TCP initialization. 226 */ 227 static void 228 tcp_zone_change(void *tag) 229 { 230 231 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 232 uma_zone_set_max(tcpcb_zone, maxsockets); 233 tcp_tw_zone_change(); 234 } 235 236 static int 237 tcp_inpcb_init(void *mem, int size, int flags) 238 { 239 struct inpcb *inp = mem; 240 241 INP_LOCK_INIT(inp, "inp", "tcpinp"); 242 return (0); 243 } 244 245 void 246 tcp_init(void) 247 { 248 249 int hashsize = TCBHASHSIZE; 250 tcp_delacktime = TCPTV_DELACK; 251 tcp_keepinit = TCPTV_KEEP_INIT; 252 tcp_keepidle = TCPTV_KEEP_IDLE; 253 tcp_keepintvl = TCPTV_KEEPINTVL; 254 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 255 tcp_msl = TCPTV_MSL; 256 tcp_rexmit_min = TCPTV_MIN; 257 tcp_rexmit_slop = TCPTV_CPU_VAR; 258 tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 259 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 260 261 INP_INFO_LOCK_INIT(&tcbinfo, "tcp"); 262 LIST_INIT(&tcb); 263 tcbinfo.ipi_listhead = &tcb; 264 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 265 if (!powerof2(hashsize)) { 266 printf("WARNING: TCB hash size not a power of 2\n"); 267 hashsize = 512; /* safe default */ 268 } 269 tcp_tcbhashsize = hashsize; 270 tcbinfo.ipi_hashbase = hashinit(hashsize, M_PCB, 271 &tcbinfo.ipi_hashmask); 272 tcbinfo.ipi_porthashbase = hashinit(hashsize, M_PCB, 273 &tcbinfo.ipi_porthashmask); 274 tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb), 275 NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 276 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 277 #ifdef INET6 278 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 279 #else /* INET6 */ 280 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 281 #endif /* INET6 */ 282 if (max_protohdr < TCP_MINPROTOHDR) 283 max_protohdr = TCP_MINPROTOHDR; 284 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 285 panic("tcp_init"); 286 #undef TCP_MINPROTOHDR 287 /* 288 * These have to be type stable for the benefit of the timers. 289 */ 290 tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 291 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 292 uma_zone_set_max(tcpcb_zone, maxsockets); 293 tcp_tw_init(); 294 syncache_init(); 295 tcp_hc_init(); 296 tcp_reass_init(); 297 ISN_LOCK_INIT(); 298 callout_init(&isn_callout, CALLOUT_MPSAFE); 299 tcp_isn_tick(NULL); 300 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 301 SHUTDOWN_PRI_DEFAULT); 302 sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 303 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 304 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 305 EVENTHANDLER_PRI_ANY); 306 } 307 308 void 309 tcp_fini(void *xtp) 310 { 311 312 callout_stop(&isn_callout); 313 } 314 315 /* 316 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 317 * tcp_template used to store this data in mbufs, but we now recopy it out 318 * of the tcpcb each time to conserve mbufs. 319 */ 320 void 321 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 322 { 323 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 324 325 INP_LOCK_ASSERT(inp); 326 327 #ifdef INET6 328 if ((inp->inp_vflag & INP_IPV6) != 0) { 329 struct ip6_hdr *ip6; 330 331 ip6 = (struct ip6_hdr *)ip_ptr; 332 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 333 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 334 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 335 (IPV6_VERSION & IPV6_VERSION_MASK); 336 ip6->ip6_nxt = IPPROTO_TCP; 337 ip6->ip6_plen = sizeof(struct tcphdr); 338 ip6->ip6_src = inp->in6p_laddr; 339 ip6->ip6_dst = inp->in6p_faddr; 340 } else 341 #endif 342 { 343 struct ip *ip; 344 345 ip = (struct ip *)ip_ptr; 346 ip->ip_v = IPVERSION; 347 ip->ip_hl = 5; 348 ip->ip_tos = inp->inp_ip_tos; 349 ip->ip_len = 0; 350 ip->ip_id = 0; 351 ip->ip_off = 0; 352 ip->ip_ttl = inp->inp_ip_ttl; 353 ip->ip_sum = 0; 354 ip->ip_p = IPPROTO_TCP; 355 ip->ip_src = inp->inp_laddr; 356 ip->ip_dst = inp->inp_faddr; 357 } 358 th->th_sport = inp->inp_lport; 359 th->th_dport = inp->inp_fport; 360 th->th_seq = 0; 361 th->th_ack = 0; 362 th->th_x2 = 0; 363 th->th_off = 5; 364 th->th_flags = 0; 365 th->th_win = 0; 366 th->th_urp = 0; 367 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 368 } 369 370 /* 371 * Create template to be used to send tcp packets on a connection. 372 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 373 * use for this function is in keepalives, which use tcp_respond. 374 */ 375 struct tcptemp * 376 tcpip_maketemplate(struct inpcb *inp) 377 { 378 struct mbuf *m; 379 struct tcptemp *n; 380 381 m = m_get(M_DONTWAIT, MT_DATA); 382 if (m == NULL) 383 return (0); 384 m->m_len = sizeof(struct tcptemp); 385 n = mtod(m, struct tcptemp *); 386 387 tcpip_fillheaders(inp, (void *)&n->tt_ipgen, (void *)&n->tt_t); 388 return (n); 389 } 390 391 /* 392 * Send a single message to the TCP at address specified by 393 * the given TCP/IP header. If m == NULL, then we make a copy 394 * of the tcpiphdr at ti and send directly to the addressed host. 395 * This is used to force keep alive messages out using the TCP 396 * template for a connection. If flags are given then we send 397 * a message back to the TCP which originated the * segment ti, 398 * and discard the mbuf containing it and any other attached mbufs. 399 * 400 * In any case the ack and sequence number of the transmitted 401 * segment are as specified by the parameters. 402 * 403 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 404 */ 405 void 406 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 407 tcp_seq ack, tcp_seq seq, int flags) 408 { 409 int tlen; 410 int win = 0; 411 struct ip *ip; 412 struct tcphdr *nth; 413 #ifdef INET6 414 struct ip6_hdr *ip6; 415 int isipv6; 416 #endif /* INET6 */ 417 int ipflags = 0; 418 struct inpcb *inp; 419 420 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 421 422 #ifdef INET6 423 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 424 ip6 = ipgen; 425 #endif /* INET6 */ 426 ip = ipgen; 427 428 if (tp != NULL) { 429 inp = tp->t_inpcb; 430 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 431 INP_LOCK_ASSERT(inp); 432 } else 433 inp = NULL; 434 435 if (tp != NULL) { 436 if (!(flags & TH_RST)) { 437 win = sbspace(&inp->inp_socket->so_rcv); 438 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 439 win = (long)TCP_MAXWIN << tp->rcv_scale; 440 } 441 } 442 if (m == NULL) { 443 m = m_gethdr(M_DONTWAIT, MT_DATA); 444 if (m == NULL) 445 return; 446 tlen = 0; 447 m->m_data += max_linkhdr; 448 #ifdef INET6 449 if (isipv6) { 450 bcopy((caddr_t)ip6, mtod(m, caddr_t), 451 sizeof(struct ip6_hdr)); 452 ip6 = mtod(m, struct ip6_hdr *); 453 nth = (struct tcphdr *)(ip6 + 1); 454 } else 455 #endif /* INET6 */ 456 { 457 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 458 ip = mtod(m, struct ip *); 459 nth = (struct tcphdr *)(ip + 1); 460 } 461 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 462 flags = TH_ACK; 463 } else { 464 m_freem(m->m_next); 465 m->m_next = NULL; 466 m->m_data = (caddr_t)ipgen; 467 /* m_len is set later */ 468 tlen = 0; 469 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 470 #ifdef INET6 471 if (isipv6) { 472 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 473 nth = (struct tcphdr *)(ip6 + 1); 474 } else 475 #endif /* INET6 */ 476 { 477 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 478 nth = (struct tcphdr *)(ip + 1); 479 } 480 if (th != nth) { 481 /* 482 * this is usually a case when an extension header 483 * exists between the IPv6 header and the 484 * TCP header. 485 */ 486 nth->th_sport = th->th_sport; 487 nth->th_dport = th->th_dport; 488 } 489 xchg(nth->th_dport, nth->th_sport, n_short); 490 #undef xchg 491 } 492 #ifdef INET6 493 if (isipv6) { 494 ip6->ip6_flow = 0; 495 ip6->ip6_vfc = IPV6_VERSION; 496 ip6->ip6_nxt = IPPROTO_TCP; 497 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 498 tlen)); 499 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 500 } else 501 #endif 502 { 503 tlen += sizeof (struct tcpiphdr); 504 ip->ip_len = tlen; 505 ip->ip_ttl = ip_defttl; 506 if (path_mtu_discovery) 507 ip->ip_off |= IP_DF; 508 } 509 m->m_len = tlen; 510 m->m_pkthdr.len = tlen; 511 m->m_pkthdr.rcvif = NULL; 512 #ifdef MAC 513 if (inp != NULL) { 514 /* 515 * Packet is associated with a socket, so allow the 516 * label of the response to reflect the socket label. 517 */ 518 INP_LOCK_ASSERT(inp); 519 mac_create_mbuf_from_inpcb(inp, m); 520 } else { 521 /* 522 * Packet is not associated with a socket, so possibly 523 * update the label in place. 524 */ 525 mac_reflect_mbuf_tcp(m); 526 } 527 #endif 528 nth->th_seq = htonl(seq); 529 nth->th_ack = htonl(ack); 530 nth->th_x2 = 0; 531 nth->th_off = sizeof (struct tcphdr) >> 2; 532 nth->th_flags = flags; 533 if (tp != NULL) 534 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 535 else 536 nth->th_win = htons((u_short)win); 537 nth->th_urp = 0; 538 #ifdef INET6 539 if (isipv6) { 540 nth->th_sum = 0; 541 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 542 sizeof(struct ip6_hdr), 543 tlen - sizeof(struct ip6_hdr)); 544 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 545 NULL, NULL); 546 } else 547 #endif /* INET6 */ 548 { 549 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 550 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 551 m->m_pkthdr.csum_flags = CSUM_TCP; 552 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 553 } 554 #ifdef TCPDEBUG 555 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 556 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 557 #endif 558 #ifdef INET6 559 if (isipv6) 560 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 561 else 562 #endif /* INET6 */ 563 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 564 } 565 566 /* 567 * Create a new TCP control block, making an 568 * empty reassembly queue and hooking it to the argument 569 * protocol control block. The `inp' parameter must have 570 * come from the zone allocator set up in tcp_init(). 571 */ 572 struct tcpcb * 573 tcp_newtcpcb(struct inpcb *inp) 574 { 575 struct tcpcb_mem *tm; 576 struct tcpcb *tp; 577 #ifdef INET6 578 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 579 #endif /* INET6 */ 580 581 tm = uma_zalloc(tcpcb_zone, M_NOWAIT | M_ZERO); 582 if (tm == NULL) 583 return (NULL); 584 tp = &tm->tcb; 585 tp->t_timers = &tm->tt; 586 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 587 tp->t_maxseg = tp->t_maxopd = 588 #ifdef INET6 589 isipv6 ? tcp_v6mssdflt : 590 #endif /* INET6 */ 591 tcp_mssdflt; 592 593 /* Set up our timeouts. */ 594 if (NET_CALLOUT_MPSAFE) 595 callout_init_mtx(&tp->t_timers->tt_timer, &inp->inp_mtx, 596 CALLOUT_RETURNUNLOCKED); 597 else 598 callout_init_mtx(&tp->t_timers->tt_timer, &inp->inp_mtx, 599 (CALLOUT_RETURNUNLOCKED|CALLOUT_NETGIANT)); 600 601 if (tcp_do_rfc1323) 602 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 603 if (tcp_do_sack) 604 tp->t_flags |= TF_SACK_PERMIT; 605 TAILQ_INIT(&tp->snd_holes); 606 tp->t_inpcb = inp; /* XXX */ 607 /* 608 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 609 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 610 * reasonable initial retransmit time. 611 */ 612 tp->t_srtt = TCPTV_SRTTBASE; 613 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 614 tp->t_rttmin = tcp_rexmit_min; 615 tp->t_rxtcur = TCPTV_RTOBASE; 616 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 617 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 618 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 619 tp->t_rcvtime = ticks; 620 tp->t_bw_rtttime = ticks; 621 /* 622 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 623 * because the socket may be bound to an IPv6 wildcard address, 624 * which may match an IPv4-mapped IPv6 address. 625 */ 626 inp->inp_ip_ttl = ip_defttl; 627 inp->inp_ppcb = tp; 628 return (tp); /* XXX */ 629 } 630 631 /* 632 * Drop a TCP connection, reporting 633 * the specified error. If connection is synchronized, 634 * then send a RST to peer. 635 */ 636 struct tcpcb * 637 tcp_drop(struct tcpcb *tp, int errno) 638 { 639 struct socket *so = tp->t_inpcb->inp_socket; 640 641 INP_INFO_WLOCK_ASSERT(&tcbinfo); 642 INP_LOCK_ASSERT(tp->t_inpcb); 643 644 if (TCPS_HAVERCVDSYN(tp->t_state)) { 645 tp->t_state = TCPS_CLOSED; 646 (void) tcp_output(tp); 647 tcpstat.tcps_drops++; 648 } else 649 tcpstat.tcps_conndrops++; 650 if (errno == ETIMEDOUT && tp->t_softerror) 651 errno = tp->t_softerror; 652 so->so_error = errno; 653 return (tcp_close(tp)); 654 } 655 656 void 657 tcp_discardcb(struct tcpcb *tp) 658 { 659 struct tseg_qent *q; 660 struct inpcb *inp = tp->t_inpcb; 661 struct socket *so = inp->inp_socket; 662 #ifdef INET6 663 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 664 #endif /* INET6 */ 665 666 INP_LOCK_ASSERT(inp); 667 668 /* 669 * Make sure that all of our timers are stopped before we 670 * delete the PCB. 671 * 672 * XXX: callout_stop() may race and a callout may already 673 * try to obtain the INP_LOCK. Only callout_drain() would 674 * stop this but it would cause a LOR thus we can't use it. 675 * The tcp_timer() function contains a lot of checks to 676 * handle this case rather gracefully. 677 */ 678 tp->t_timers->tt_active = 0; 679 callout_stop(&tp->t_timers->tt_timer); 680 681 /* 682 * If we got enough samples through the srtt filter, 683 * save the rtt and rttvar in the routing entry. 684 * 'Enough' is arbitrarily defined as 4 rtt samples. 685 * 4 samples is enough for the srtt filter to converge 686 * to within enough % of the correct value; fewer samples 687 * and we could save a bogus rtt. The danger is not high 688 * as tcp quickly recovers from everything. 689 * XXX: Works very well but needs some more statistics! 690 */ 691 if (tp->t_rttupdated >= 4) { 692 struct hc_metrics_lite metrics; 693 u_long ssthresh; 694 695 bzero(&metrics, sizeof(metrics)); 696 /* 697 * Update the ssthresh always when the conditions below 698 * are satisfied. This gives us better new start value 699 * for the congestion avoidance for new connections. 700 * ssthresh is only set if packet loss occured on a session. 701 * 702 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 703 * being torn down. Ideally this code would not use 'so'. 704 */ 705 ssthresh = tp->snd_ssthresh; 706 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 707 /* 708 * convert the limit from user data bytes to 709 * packets then to packet data bytes. 710 */ 711 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 712 if (ssthresh < 2) 713 ssthresh = 2; 714 ssthresh *= (u_long)(tp->t_maxseg + 715 #ifdef INET6 716 (isipv6 ? sizeof (struct ip6_hdr) + 717 sizeof (struct tcphdr) : 718 #endif 719 sizeof (struct tcpiphdr) 720 #ifdef INET6 721 ) 722 #endif 723 ); 724 } else 725 ssthresh = 0; 726 metrics.rmx_ssthresh = ssthresh; 727 728 metrics.rmx_rtt = tp->t_srtt; 729 metrics.rmx_rttvar = tp->t_rttvar; 730 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 731 metrics.rmx_bandwidth = tp->snd_bandwidth; 732 metrics.rmx_cwnd = tp->snd_cwnd; 733 metrics.rmx_sendpipe = 0; 734 metrics.rmx_recvpipe = 0; 735 736 tcp_hc_update(&inp->inp_inc, &metrics); 737 } 738 739 /* free the reassembly queue, if any */ 740 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) { 741 LIST_REMOVE(q, tqe_q); 742 m_freem(q->tqe_m); 743 uma_zfree(tcp_reass_zone, q); 744 tp->t_segqlen--; 745 tcp_reass_qsize--; 746 } 747 tcp_free_sackholes(tp); 748 inp->inp_ppcb = NULL; 749 tp->t_inpcb = NULL; 750 uma_zfree(tcpcb_zone, tp); 751 } 752 753 /* 754 * Attempt to close a TCP control block, marking it as dropped, and freeing 755 * the socket if we hold the only reference. 756 */ 757 struct tcpcb * 758 tcp_close(struct tcpcb *tp) 759 { 760 struct inpcb *inp = tp->t_inpcb; 761 struct socket *so; 762 763 INP_INFO_WLOCK_ASSERT(&tcbinfo); 764 INP_LOCK_ASSERT(inp); 765 766 in_pcbdrop(inp); 767 tcpstat.tcps_closed++; 768 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 769 so = inp->inp_socket; 770 soisdisconnected(so); 771 if (inp->inp_vflag & INP_SOCKREF) { 772 KASSERT(so->so_state & SS_PROTOREF, 773 ("tcp_close: !SS_PROTOREF")); 774 inp->inp_vflag &= ~INP_SOCKREF; 775 INP_UNLOCK(inp); 776 ACCEPT_LOCK(); 777 SOCK_LOCK(so); 778 so->so_state &= ~SS_PROTOREF; 779 sofree(so); 780 return (NULL); 781 } 782 return (tp); 783 } 784 785 void 786 tcp_drain(void) 787 { 788 789 if (do_tcpdrain) { 790 struct inpcb *inpb; 791 struct tcpcb *tcpb; 792 struct tseg_qent *te; 793 794 /* 795 * Walk the tcpbs, if existing, and flush the reassembly queue, 796 * if there is one... 797 * XXX: The "Net/3" implementation doesn't imply that the TCP 798 * reassembly queue should be flushed, but in a situation 799 * where we're really low on mbufs, this is potentially 800 * usefull. 801 */ 802 INP_INFO_RLOCK(&tcbinfo); 803 LIST_FOREACH(inpb, tcbinfo.ipi_listhead, inp_list) { 804 if (inpb->inp_vflag & INP_TIMEWAIT) 805 continue; 806 INP_LOCK(inpb); 807 if ((tcpb = intotcpcb(inpb)) != NULL) { 808 while ((te = LIST_FIRST(&tcpb->t_segq)) 809 != NULL) { 810 LIST_REMOVE(te, tqe_q); 811 m_freem(te->tqe_m); 812 uma_zfree(tcp_reass_zone, te); 813 tcpb->t_segqlen--; 814 tcp_reass_qsize--; 815 } 816 tcp_clean_sackreport(tcpb); 817 } 818 INP_UNLOCK(inpb); 819 } 820 INP_INFO_RUNLOCK(&tcbinfo); 821 } 822 } 823 824 /* 825 * Notify a tcp user of an asynchronous error; 826 * store error as soft error, but wake up user 827 * (for now, won't do anything until can select for soft error). 828 * 829 * Do not wake up user since there currently is no mechanism for 830 * reporting soft errors (yet - a kqueue filter may be added). 831 */ 832 static struct inpcb * 833 tcp_notify(struct inpcb *inp, int error) 834 { 835 struct tcpcb *tp; 836 837 INP_INFO_WLOCK_ASSERT(&tcbinfo); 838 INP_LOCK_ASSERT(inp); 839 840 if ((inp->inp_vflag & INP_TIMEWAIT) || 841 (inp->inp_vflag & INP_DROPPED)) 842 return (inp); 843 844 tp = intotcpcb(inp); 845 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 846 847 /* 848 * Ignore some errors if we are hooked up. 849 * If connection hasn't completed, has retransmitted several times, 850 * and receives a second error, give up now. This is better 851 * than waiting a long time to establish a connection that 852 * can never complete. 853 */ 854 if (tp->t_state == TCPS_ESTABLISHED && 855 (error == EHOSTUNREACH || error == ENETUNREACH || 856 error == EHOSTDOWN)) { 857 return (inp); 858 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 859 tp->t_softerror) { 860 tp = tcp_drop(tp, error); 861 if (tp != NULL) 862 return (inp); 863 else 864 return (NULL); 865 } else { 866 tp->t_softerror = error; 867 return (inp); 868 } 869 #if 0 870 wakeup( &so->so_timeo); 871 sorwakeup(so); 872 sowwakeup(so); 873 #endif 874 } 875 876 static int 877 tcp_pcblist(SYSCTL_HANDLER_ARGS) 878 { 879 int error, i, n; 880 struct inpcb *inp, **inp_list; 881 inp_gen_t gencnt; 882 struct xinpgen xig; 883 884 /* 885 * The process of preparing the TCB list is too time-consuming and 886 * resource-intensive to repeat twice on every request. 887 */ 888 if (req->oldptr == NULL) { 889 n = tcbinfo.ipi_count; 890 req->oldidx = 2 * (sizeof xig) 891 + (n + n/8) * sizeof(struct xtcpcb); 892 return (0); 893 } 894 895 if (req->newptr != NULL) 896 return (EPERM); 897 898 /* 899 * OK, now we're committed to doing something. 900 */ 901 INP_INFO_RLOCK(&tcbinfo); 902 gencnt = tcbinfo.ipi_gencnt; 903 n = tcbinfo.ipi_count; 904 INP_INFO_RUNLOCK(&tcbinfo); 905 906 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 907 + n * sizeof(struct xtcpcb)); 908 if (error != 0) 909 return (error); 910 911 xig.xig_len = sizeof xig; 912 xig.xig_count = n; 913 xig.xig_gen = gencnt; 914 xig.xig_sogen = so_gencnt; 915 error = SYSCTL_OUT(req, &xig, sizeof xig); 916 if (error) 917 return (error); 918 919 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 920 if (inp_list == NULL) 921 return (ENOMEM); 922 923 INP_INFO_RLOCK(&tcbinfo); 924 for (inp = LIST_FIRST(tcbinfo.ipi_listhead), i = 0; inp != NULL && i 925 < n; inp = LIST_NEXT(inp, inp_list)) { 926 INP_LOCK(inp); 927 if (inp->inp_gencnt <= gencnt) { 928 /* 929 * XXX: This use of cr_cansee(), introduced with 930 * TCP state changes, is not quite right, but for 931 * now, better than nothing. 932 */ 933 if (inp->inp_vflag & INP_TIMEWAIT) { 934 if (intotw(inp) != NULL) 935 error = cr_cansee(req->td->td_ucred, 936 intotw(inp)->tw_cred); 937 else 938 error = EINVAL; /* Skip this inp. */ 939 } else 940 error = cr_canseesocket(req->td->td_ucred, 941 inp->inp_socket); 942 if (error == 0) 943 inp_list[i++] = inp; 944 } 945 INP_UNLOCK(inp); 946 } 947 INP_INFO_RUNLOCK(&tcbinfo); 948 n = i; 949 950 error = 0; 951 for (i = 0; i < n; i++) { 952 inp = inp_list[i]; 953 INP_LOCK(inp); 954 if (inp->inp_gencnt <= gencnt) { 955 struct xtcpcb xt; 956 void *inp_ppcb; 957 958 bzero(&xt, sizeof(xt)); 959 xt.xt_len = sizeof xt; 960 /* XXX should avoid extra copy */ 961 bcopy(inp, &xt.xt_inp, sizeof *inp); 962 inp_ppcb = inp->inp_ppcb; 963 if (inp_ppcb == NULL) 964 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 965 else if (inp->inp_vflag & INP_TIMEWAIT) { 966 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 967 xt.xt_tp.t_state = TCPS_TIME_WAIT; 968 } else 969 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 970 if (inp->inp_socket != NULL) 971 sotoxsocket(inp->inp_socket, &xt.xt_socket); 972 else { 973 bzero(&xt.xt_socket, sizeof xt.xt_socket); 974 xt.xt_socket.xso_protocol = IPPROTO_TCP; 975 } 976 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 977 INP_UNLOCK(inp); 978 error = SYSCTL_OUT(req, &xt, sizeof xt); 979 } else 980 INP_UNLOCK(inp); 981 982 } 983 if (!error) { 984 /* 985 * Give the user an updated idea of our state. 986 * If the generation differs from what we told 987 * her before, she knows that something happened 988 * while we were processing this request, and it 989 * might be necessary to retry. 990 */ 991 INP_INFO_RLOCK(&tcbinfo); 992 xig.xig_gen = tcbinfo.ipi_gencnt; 993 xig.xig_sogen = so_gencnt; 994 xig.xig_count = tcbinfo.ipi_count; 995 INP_INFO_RUNLOCK(&tcbinfo); 996 error = SYSCTL_OUT(req, &xig, sizeof xig); 997 } 998 free(inp_list, M_TEMP); 999 return (error); 1000 } 1001 1002 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1003 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1004 1005 static int 1006 tcp_getcred(SYSCTL_HANDLER_ARGS) 1007 { 1008 struct xucred xuc; 1009 struct sockaddr_in addrs[2]; 1010 struct inpcb *inp; 1011 int error; 1012 1013 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1014 if (error) 1015 return (error); 1016 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1017 if (error) 1018 return (error); 1019 INP_INFO_RLOCK(&tcbinfo); 1020 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 1021 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1022 if (inp == NULL) { 1023 error = ENOENT; 1024 goto outunlocked; 1025 } 1026 INP_LOCK(inp); 1027 if (inp->inp_socket == NULL) { 1028 error = ENOENT; 1029 goto out; 1030 } 1031 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1032 if (error) 1033 goto out; 1034 cru2x(inp->inp_socket->so_cred, &xuc); 1035 out: 1036 INP_UNLOCK(inp); 1037 outunlocked: 1038 INP_INFO_RUNLOCK(&tcbinfo); 1039 if (error == 0) 1040 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1041 return (error); 1042 } 1043 1044 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1045 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1046 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1047 1048 #ifdef INET6 1049 static int 1050 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1051 { 1052 struct xucred xuc; 1053 struct sockaddr_in6 addrs[2]; 1054 struct inpcb *inp; 1055 int error, mapped = 0; 1056 1057 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1058 if (error) 1059 return (error); 1060 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1061 if (error) 1062 return (error); 1063 if ((error = sa6_embedscope(&addrs[0], ip6_use_defzone)) != 0 || 1064 (error = sa6_embedscope(&addrs[1], ip6_use_defzone)) != 0) { 1065 return (error); 1066 } 1067 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1068 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1069 mapped = 1; 1070 else 1071 return (EINVAL); 1072 } 1073 1074 INP_INFO_RLOCK(&tcbinfo); 1075 if (mapped == 1) 1076 inp = in_pcblookup_hash(&tcbinfo, 1077 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1078 addrs[1].sin6_port, 1079 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1080 addrs[0].sin6_port, 1081 0, NULL); 1082 else 1083 inp = in6_pcblookup_hash(&tcbinfo, 1084 &addrs[1].sin6_addr, addrs[1].sin6_port, 1085 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1086 if (inp == NULL) { 1087 error = ENOENT; 1088 goto outunlocked; 1089 } 1090 INP_LOCK(inp); 1091 if (inp->inp_socket == NULL) { 1092 error = ENOENT; 1093 goto out; 1094 } 1095 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1096 if (error) 1097 goto out; 1098 cru2x(inp->inp_socket->so_cred, &xuc); 1099 out: 1100 INP_UNLOCK(inp); 1101 outunlocked: 1102 INP_INFO_RUNLOCK(&tcbinfo); 1103 if (error == 0) 1104 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1105 return (error); 1106 } 1107 1108 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1109 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1110 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1111 #endif 1112 1113 1114 void 1115 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1116 { 1117 struct ip *ip = vip; 1118 struct tcphdr *th; 1119 struct in_addr faddr; 1120 struct inpcb *inp; 1121 struct tcpcb *tp; 1122 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1123 struct icmp *icp; 1124 struct in_conninfo inc; 1125 tcp_seq icmp_tcp_seq; 1126 int mtu; 1127 1128 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1129 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1130 return; 1131 1132 if (cmd == PRC_MSGSIZE) 1133 notify = tcp_mtudisc; 1134 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1135 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1136 notify = tcp_drop_syn_sent; 1137 /* 1138 * Redirects don't need to be handled up here. 1139 */ 1140 else if (PRC_IS_REDIRECT(cmd)) 1141 return; 1142 /* 1143 * Source quench is depreciated. 1144 */ 1145 else if (cmd == PRC_QUENCH) 1146 return; 1147 /* 1148 * Hostdead is ugly because it goes linearly through all PCBs. 1149 * XXX: We never get this from ICMP, otherwise it makes an 1150 * excellent DoS attack on machines with many connections. 1151 */ 1152 else if (cmd == PRC_HOSTDEAD) 1153 ip = NULL; 1154 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1155 return; 1156 if (ip != NULL) { 1157 icp = (struct icmp *)((caddr_t)ip 1158 - offsetof(struct icmp, icmp_ip)); 1159 th = (struct tcphdr *)((caddr_t)ip 1160 + (ip->ip_hl << 2)); 1161 INP_INFO_WLOCK(&tcbinfo); 1162 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1163 ip->ip_src, th->th_sport, 0, NULL); 1164 if (inp != NULL) { 1165 INP_LOCK(inp); 1166 if (!(inp->inp_vflag & INP_TIMEWAIT) && 1167 !(inp->inp_vflag & INP_DROPPED) && 1168 !(inp->inp_socket == NULL)) { 1169 icmp_tcp_seq = htonl(th->th_seq); 1170 tp = intotcpcb(inp); 1171 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1172 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1173 if (cmd == PRC_MSGSIZE) { 1174 /* 1175 * MTU discovery: 1176 * If we got a needfrag set the MTU 1177 * in the route to the suggested new 1178 * value (if given) and then notify. 1179 */ 1180 bzero(&inc, sizeof(inc)); 1181 inc.inc_flags = 0; /* IPv4 */ 1182 inc.inc_faddr = faddr; 1183 1184 mtu = ntohs(icp->icmp_nextmtu); 1185 /* 1186 * If no alternative MTU was 1187 * proposed, try the next smaller 1188 * one. ip->ip_len has already 1189 * been swapped in icmp_input(). 1190 */ 1191 if (!mtu) 1192 mtu = ip_next_mtu(ip->ip_len, 1193 1); 1194 if (mtu < max(296, (tcp_minmss) 1195 + sizeof(struct tcpiphdr))) 1196 mtu = 0; 1197 if (!mtu) 1198 mtu = tcp_mssdflt 1199 + sizeof(struct tcpiphdr); 1200 /* 1201 * Only cache the the MTU if it 1202 * is smaller than the interface 1203 * or route MTU. tcp_mtudisc() 1204 * will do right thing by itself. 1205 */ 1206 if (mtu <= tcp_maxmtu(&inc, NULL)) 1207 tcp_hc_updatemtu(&inc, mtu); 1208 } 1209 1210 inp = (*notify)(inp, inetctlerrmap[cmd]); 1211 } 1212 } 1213 if (inp != NULL) 1214 INP_UNLOCK(inp); 1215 } else { 1216 inc.inc_fport = th->th_dport; 1217 inc.inc_lport = th->th_sport; 1218 inc.inc_faddr = faddr; 1219 inc.inc_laddr = ip->ip_src; 1220 #ifdef INET6 1221 inc.inc_isipv6 = 0; 1222 #endif 1223 syncache_unreach(&inc, th); 1224 } 1225 INP_INFO_WUNLOCK(&tcbinfo); 1226 } else 1227 in_pcbnotifyall(&tcbinfo, faddr, inetctlerrmap[cmd], notify); 1228 } 1229 1230 #ifdef INET6 1231 void 1232 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1233 { 1234 struct tcphdr th; 1235 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1236 struct ip6_hdr *ip6; 1237 struct mbuf *m; 1238 struct ip6ctlparam *ip6cp = NULL; 1239 const struct sockaddr_in6 *sa6_src = NULL; 1240 int off; 1241 struct tcp_portonly { 1242 u_int16_t th_sport; 1243 u_int16_t th_dport; 1244 } *thp; 1245 1246 if (sa->sa_family != AF_INET6 || 1247 sa->sa_len != sizeof(struct sockaddr_in6)) 1248 return; 1249 1250 if (cmd == PRC_MSGSIZE) 1251 notify = tcp_mtudisc; 1252 else if (!PRC_IS_REDIRECT(cmd) && 1253 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1254 return; 1255 /* Source quench is depreciated. */ 1256 else if (cmd == PRC_QUENCH) 1257 return; 1258 1259 /* if the parameter is from icmp6, decode it. */ 1260 if (d != NULL) { 1261 ip6cp = (struct ip6ctlparam *)d; 1262 m = ip6cp->ip6c_m; 1263 ip6 = ip6cp->ip6c_ip6; 1264 off = ip6cp->ip6c_off; 1265 sa6_src = ip6cp->ip6c_src; 1266 } else { 1267 m = NULL; 1268 ip6 = NULL; 1269 off = 0; /* fool gcc */ 1270 sa6_src = &sa6_any; 1271 } 1272 1273 if (ip6 != NULL) { 1274 struct in_conninfo inc; 1275 /* 1276 * XXX: We assume that when IPV6 is non NULL, 1277 * M and OFF are valid. 1278 */ 1279 1280 /* check if we can safely examine src and dst ports */ 1281 if (m->m_pkthdr.len < off + sizeof(*thp)) 1282 return; 1283 1284 bzero(&th, sizeof(th)); 1285 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1286 1287 in6_pcbnotify(&tcbinfo, sa, th.th_dport, 1288 (struct sockaddr *)ip6cp->ip6c_src, 1289 th.th_sport, cmd, NULL, notify); 1290 1291 inc.inc_fport = th.th_dport; 1292 inc.inc_lport = th.th_sport; 1293 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1294 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1295 inc.inc_isipv6 = 1; 1296 INP_INFO_WLOCK(&tcbinfo); 1297 syncache_unreach(&inc, &th); 1298 INP_INFO_WUNLOCK(&tcbinfo); 1299 } else 1300 in6_pcbnotify(&tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1301 0, cmd, NULL, notify); 1302 } 1303 #endif /* INET6 */ 1304 1305 1306 /* 1307 * Following is where TCP initial sequence number generation occurs. 1308 * 1309 * There are two places where we must use initial sequence numbers: 1310 * 1. In SYN-ACK packets. 1311 * 2. In SYN packets. 1312 * 1313 * All ISNs for SYN-ACK packets are generated by the syncache. See 1314 * tcp_syncache.c for details. 1315 * 1316 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1317 * depends on this property. In addition, these ISNs should be 1318 * unguessable so as to prevent connection hijacking. To satisfy 1319 * the requirements of this situation, the algorithm outlined in 1320 * RFC 1948 is used, with only small modifications. 1321 * 1322 * Implementation details: 1323 * 1324 * Time is based off the system timer, and is corrected so that it 1325 * increases by one megabyte per second. This allows for proper 1326 * recycling on high speed LANs while still leaving over an hour 1327 * before rollover. 1328 * 1329 * As reading the *exact* system time is too expensive to be done 1330 * whenever setting up a TCP connection, we increment the time 1331 * offset in two ways. First, a small random positive increment 1332 * is added to isn_offset for each connection that is set up. 1333 * Second, the function tcp_isn_tick fires once per clock tick 1334 * and increments isn_offset as necessary so that sequence numbers 1335 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1336 * random positive increments serve only to ensure that the same 1337 * exact sequence number is never sent out twice (as could otherwise 1338 * happen when a port is recycled in less than the system tick 1339 * interval.) 1340 * 1341 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1342 * between seeding of isn_secret. This is normally set to zero, 1343 * as reseeding should not be necessary. 1344 * 1345 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1346 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1347 * general, this means holding an exclusive (write) lock. 1348 */ 1349 1350 #define ISN_BYTES_PER_SECOND 1048576 1351 #define ISN_STATIC_INCREMENT 4096 1352 #define ISN_RANDOM_INCREMENT (4096 - 1) 1353 1354 static u_char isn_secret[32]; 1355 static int isn_last_reseed; 1356 static u_int32_t isn_offset, isn_offset_old; 1357 static MD5_CTX isn_ctx; 1358 1359 tcp_seq 1360 tcp_new_isn(struct tcpcb *tp) 1361 { 1362 u_int32_t md5_buffer[4]; 1363 tcp_seq new_isn; 1364 1365 INP_LOCK_ASSERT(tp->t_inpcb); 1366 1367 ISN_LOCK(); 1368 /* Seed if this is the first use, reseed if requested. */ 1369 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1370 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1371 < (u_int)ticks))) { 1372 read_random(&isn_secret, sizeof(isn_secret)); 1373 isn_last_reseed = ticks; 1374 } 1375 1376 /* Compute the md5 hash and return the ISN. */ 1377 MD5Init(&isn_ctx); 1378 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1379 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1380 #ifdef INET6 1381 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1382 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1383 sizeof(struct in6_addr)); 1384 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1385 sizeof(struct in6_addr)); 1386 } else 1387 #endif 1388 { 1389 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1390 sizeof(struct in_addr)); 1391 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1392 sizeof(struct in_addr)); 1393 } 1394 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1395 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1396 new_isn = (tcp_seq) md5_buffer[0]; 1397 isn_offset += ISN_STATIC_INCREMENT + 1398 (arc4random() & ISN_RANDOM_INCREMENT); 1399 new_isn += isn_offset; 1400 ISN_UNLOCK(); 1401 return (new_isn); 1402 } 1403 1404 /* 1405 * Increment the offset to the next ISN_BYTES_PER_SECOND / hz boundary 1406 * to keep time flowing at a relatively constant rate. If the random 1407 * increments have already pushed us past the projected offset, do nothing. 1408 */ 1409 static void 1410 tcp_isn_tick(void *xtp) 1411 { 1412 u_int32_t projected_offset; 1413 1414 ISN_LOCK(); 1415 projected_offset = isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1416 1417 if (projected_offset > isn_offset) 1418 isn_offset = projected_offset; 1419 1420 isn_offset_old = isn_offset; 1421 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1422 ISN_UNLOCK(); 1423 } 1424 1425 /* 1426 * When a specific ICMP unreachable message is received and the 1427 * connection state is SYN-SENT, drop the connection. This behavior 1428 * is controlled by the icmp_may_rst sysctl. 1429 */ 1430 struct inpcb * 1431 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1432 { 1433 struct tcpcb *tp; 1434 1435 INP_INFO_WLOCK_ASSERT(&tcbinfo); 1436 INP_LOCK_ASSERT(inp); 1437 1438 if ((inp->inp_vflag & INP_TIMEWAIT) || 1439 (inp->inp_vflag & INP_DROPPED)) 1440 return (inp); 1441 1442 tp = intotcpcb(inp); 1443 if (tp->t_state != TCPS_SYN_SENT) 1444 return (inp); 1445 1446 tp = tcp_drop(tp, errno); 1447 if (tp != NULL) 1448 return (inp); 1449 else 1450 return (NULL); 1451 } 1452 1453 /* 1454 * When `need fragmentation' ICMP is received, update our idea of the MSS 1455 * based on the new value in the route. Also nudge TCP to send something, 1456 * since we know the packet we just sent was dropped. 1457 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1458 */ 1459 struct inpcb * 1460 tcp_mtudisc(struct inpcb *inp, int errno) 1461 { 1462 struct tcpcb *tp; 1463 struct socket *so = inp->inp_socket; 1464 u_int maxmtu; 1465 u_int romtu; 1466 int mss; 1467 #ifdef INET6 1468 int isipv6; 1469 #endif /* INET6 */ 1470 1471 INP_LOCK_ASSERT(inp); 1472 if ((inp->inp_vflag & INP_TIMEWAIT) || 1473 (inp->inp_vflag & INP_DROPPED)) 1474 return (inp); 1475 1476 tp = intotcpcb(inp); 1477 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1478 1479 #ifdef INET6 1480 isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1481 #endif 1482 maxmtu = tcp_hc_getmtu(&inp->inp_inc); /* IPv4 and IPv6 */ 1483 romtu = 1484 #ifdef INET6 1485 isipv6 ? tcp_maxmtu6(&inp->inp_inc, NULL) : 1486 #endif /* INET6 */ 1487 tcp_maxmtu(&inp->inp_inc, NULL); 1488 if (!maxmtu) 1489 maxmtu = romtu; 1490 else 1491 maxmtu = min(maxmtu, romtu); 1492 if (!maxmtu) { 1493 tp->t_maxopd = tp->t_maxseg = 1494 #ifdef INET6 1495 isipv6 ? tcp_v6mssdflt : 1496 #endif /* INET6 */ 1497 tcp_mssdflt; 1498 return (inp); 1499 } 1500 mss = maxmtu - 1501 #ifdef INET6 1502 (isipv6 ? sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1503 #endif /* INET6 */ 1504 sizeof(struct tcpiphdr) 1505 #ifdef INET6 1506 ) 1507 #endif /* INET6 */ 1508 ; 1509 1510 /* 1511 * XXX - The above conditional probably violates the TCP 1512 * spec. The problem is that, since we don't know the 1513 * other end's MSS, we are supposed to use a conservative 1514 * default. But, if we do that, then MTU discovery will 1515 * never actually take place, because the conservative 1516 * default is much less than the MTUs typically seen 1517 * on the Internet today. For the moment, we'll sweep 1518 * this under the carpet. 1519 * 1520 * The conservative default might not actually be a problem 1521 * if the only case this occurs is when sending an initial 1522 * SYN with options and data to a host we've never talked 1523 * to before. Then, they will reply with an MSS value which 1524 * will get recorded and the new parameters should get 1525 * recomputed. For Further Study. 1526 */ 1527 if (tp->t_maxopd <= mss) 1528 return (inp); 1529 tp->t_maxopd = mss; 1530 1531 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1532 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1533 mss -= TCPOLEN_TSTAMP_APPA; 1534 #if (MCLBYTES & (MCLBYTES - 1)) == 0 1535 if (mss > MCLBYTES) 1536 mss &= ~(MCLBYTES-1); 1537 #else 1538 if (mss > MCLBYTES) 1539 mss = mss / MCLBYTES * MCLBYTES; 1540 #endif 1541 if (so->so_snd.sb_hiwat < mss) 1542 mss = so->so_snd.sb_hiwat; 1543 1544 tp->t_maxseg = mss; 1545 1546 tcpstat.tcps_mturesent++; 1547 tp->t_rtttime = 0; 1548 tp->snd_nxt = tp->snd_una; 1549 tcp_free_sackholes(tp); 1550 tp->snd_recover = tp->snd_max; 1551 if (tp->t_flags & TF_SACK_PERMIT) 1552 EXIT_FASTRECOVERY(tp); 1553 tcp_output(tp); 1554 return (inp); 1555 } 1556 1557 /* 1558 * Look-up the routing entry to the peer of this inpcb. If no route 1559 * is found and it cannot be allocated, then return NULL. This routine 1560 * is called by TCP routines that access the rmx structure and by tcp_mss 1561 * to get the interface MTU. 1562 */ 1563 u_long 1564 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1565 { 1566 struct route sro; 1567 struct sockaddr_in *dst; 1568 struct ifnet *ifp; 1569 u_long maxmtu = 0; 1570 1571 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1572 1573 bzero(&sro, sizeof(sro)); 1574 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1575 dst = (struct sockaddr_in *)&sro.ro_dst; 1576 dst->sin_family = AF_INET; 1577 dst->sin_len = sizeof(*dst); 1578 dst->sin_addr = inc->inc_faddr; 1579 rtalloc_ign(&sro, RTF_CLONING); 1580 } 1581 if (sro.ro_rt != NULL) { 1582 ifp = sro.ro_rt->rt_ifp; 1583 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1584 maxmtu = ifp->if_mtu; 1585 else 1586 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1587 1588 /* Report additional interface capabilities. */ 1589 if (flags != NULL) { 1590 if (ifp->if_capenable & IFCAP_TSO4 && 1591 ifp->if_hwassist & CSUM_TSO) 1592 *flags |= CSUM_TSO; 1593 } 1594 RTFREE(sro.ro_rt); 1595 } 1596 return (maxmtu); 1597 } 1598 1599 #ifdef INET6 1600 u_long 1601 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1602 { 1603 struct route_in6 sro6; 1604 struct ifnet *ifp; 1605 u_long maxmtu = 0; 1606 1607 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1608 1609 bzero(&sro6, sizeof(sro6)); 1610 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1611 sro6.ro_dst.sin6_family = AF_INET6; 1612 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1613 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1614 rtalloc_ign((struct route *)&sro6, RTF_CLONING); 1615 } 1616 if (sro6.ro_rt != NULL) { 1617 ifp = sro6.ro_rt->rt_ifp; 1618 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1619 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1620 else 1621 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1622 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1623 1624 /* Report additional interface capabilities. */ 1625 if (flags != NULL) { 1626 if (ifp->if_capenable & IFCAP_TSO6 && 1627 ifp->if_hwassist & CSUM_TSO) 1628 *flags |= CSUM_TSO; 1629 } 1630 RTFREE(sro6.ro_rt); 1631 } 1632 1633 return (maxmtu); 1634 } 1635 #endif /* INET6 */ 1636 1637 #ifdef IPSEC 1638 /* compute ESP/AH header size for TCP, including outer IP header. */ 1639 size_t 1640 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1641 { 1642 struct inpcb *inp; 1643 struct mbuf *m; 1644 size_t hdrsiz; 1645 struct ip *ip; 1646 #ifdef INET6 1647 struct ip6_hdr *ip6; 1648 #endif 1649 struct tcphdr *th; 1650 1651 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1652 return (0); 1653 MGETHDR(m, M_DONTWAIT, MT_DATA); 1654 if (!m) 1655 return (0); 1656 1657 #ifdef INET6 1658 if ((inp->inp_vflag & INP_IPV6) != 0) { 1659 ip6 = mtod(m, struct ip6_hdr *); 1660 th = (struct tcphdr *)(ip6 + 1); 1661 m->m_pkthdr.len = m->m_len = 1662 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1663 tcpip_fillheaders(inp, ip6, th); 1664 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1665 } else 1666 #endif /* INET6 */ 1667 { 1668 ip = mtod(m, struct ip *); 1669 th = (struct tcphdr *)(ip + 1); 1670 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1671 tcpip_fillheaders(inp, ip, th); 1672 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1673 } 1674 1675 m_free(m); 1676 return (hdrsiz); 1677 } 1678 #endif /* IPSEC */ 1679 1680 /* 1681 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1682 * 1683 * This code attempts to calculate the bandwidth-delay product as a 1684 * means of determining the optimal window size to maximize bandwidth, 1685 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1686 * routers. This code also does a fairly good job keeping RTTs in check 1687 * across slow links like modems. We implement an algorithm which is very 1688 * similar (but not meant to be) TCP/Vegas. The code operates on the 1689 * transmitter side of a TCP connection and so only effects the transmit 1690 * side of the connection. 1691 * 1692 * BACKGROUND: TCP makes no provision for the management of buffer space 1693 * at the end points or at the intermediate routers and switches. A TCP 1694 * stream, whether using NewReno or not, will eventually buffer as 1695 * many packets as it is able and the only reason this typically works is 1696 * due to the fairly small default buffers made available for a connection 1697 * (typicaly 16K or 32K). As machines use larger windows and/or window 1698 * scaling it is now fairly easy for even a single TCP connection to blow-out 1699 * all available buffer space not only on the local interface, but on 1700 * intermediate routers and switches as well. NewReno makes a misguided 1701 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1702 * then backing off, then steadily increasing the window again until another 1703 * failure occurs, ad-infinitum. This results in terrible oscillation that 1704 * is only made worse as network loads increase and the idea of intentionally 1705 * blowing out network buffers is, frankly, a terrible way to manage network 1706 * resources. 1707 * 1708 * It is far better to limit the transmit window prior to the failure 1709 * condition being achieved. There are two general ways to do this: First 1710 * you can 'scan' through different transmit window sizes and locate the 1711 * point where the RTT stops increasing, indicating that you have filled the 1712 * pipe, then scan backwards until you note that RTT stops decreasing, then 1713 * repeat ad-infinitum. This method works in principle but has severe 1714 * implementation issues due to RTT variances, timer granularity, and 1715 * instability in the algorithm which can lead to many false positives and 1716 * create oscillations as well as interact badly with other TCP streams 1717 * implementing the same algorithm. 1718 * 1719 * The second method is to limit the window to the bandwidth delay product 1720 * of the link. This is the method we implement. RTT variances and our 1721 * own manipulation of the congestion window, bwnd, can potentially 1722 * destabilize the algorithm. For this reason we have to stabilize the 1723 * elements used to calculate the window. We do this by using the minimum 1724 * observed RTT, the long term average of the observed bandwidth, and 1725 * by adding two segments worth of slop. It isn't perfect but it is able 1726 * to react to changing conditions and gives us a very stable basis on 1727 * which to extend the algorithm. 1728 */ 1729 void 1730 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1731 { 1732 u_long bw; 1733 u_long bwnd; 1734 int save_ticks; 1735 1736 INP_LOCK_ASSERT(tp->t_inpcb); 1737 1738 /* 1739 * If inflight_enable is disabled in the middle of a tcp connection, 1740 * make sure snd_bwnd is effectively disabled. 1741 */ 1742 if (tcp_inflight_enable == 0 || tp->t_rttlow < tcp_inflight_rttthresh) { 1743 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1744 tp->snd_bandwidth = 0; 1745 return; 1746 } 1747 1748 /* 1749 * Figure out the bandwidth. Due to the tick granularity this 1750 * is a very rough number and it MUST be averaged over a fairly 1751 * long period of time. XXX we need to take into account a link 1752 * that is not using all available bandwidth, but for now our 1753 * slop will ramp us up if this case occurs and the bandwidth later 1754 * increases. 1755 * 1756 * Note: if ticks rollover 'bw' may wind up negative. We must 1757 * effectively reset t_bw_rtttime for this case. 1758 */ 1759 save_ticks = ticks; 1760 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 1761 return; 1762 1763 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 1764 (save_ticks - tp->t_bw_rtttime); 1765 tp->t_bw_rtttime = save_ticks; 1766 tp->t_bw_rtseq = ack_seq; 1767 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 1768 return; 1769 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1770 1771 tp->snd_bandwidth = bw; 1772 1773 /* 1774 * Calculate the semi-static bandwidth delay product, plus two maximal 1775 * segments. The additional slop puts us squarely in the sweet 1776 * spot and also handles the bandwidth run-up case and stabilization. 1777 * Without the slop we could be locking ourselves into a lower 1778 * bandwidth. 1779 * 1780 * Situations Handled: 1781 * (1) Prevents over-queueing of packets on LANs, especially on 1782 * high speed LANs, allowing larger TCP buffers to be 1783 * specified, and also does a good job preventing 1784 * over-queueing of packets over choke points like modems 1785 * (at least for the transmit side). 1786 * 1787 * (2) Is able to handle changing network loads (bandwidth 1788 * drops so bwnd drops, bandwidth increases so bwnd 1789 * increases). 1790 * 1791 * (3) Theoretically should stabilize in the face of multiple 1792 * connections implementing the same algorithm (this may need 1793 * a little work). 1794 * 1795 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1796 * be adjusted with a sysctl but typically only needs to be 1797 * on very slow connections. A value no smaller then 5 1798 * should be used, but only reduce this default if you have 1799 * no other choice. 1800 */ 1801 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1802 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + tcp_inflight_stab * tp->t_maxseg / 10; 1803 #undef USERTT 1804 1805 if (tcp_inflight_debug > 0) { 1806 static int ltime; 1807 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1808 ltime = ticks; 1809 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1810 tp, 1811 bw, 1812 tp->t_rttbest, 1813 tp->t_srtt, 1814 bwnd 1815 ); 1816 } 1817 } 1818 if ((long)bwnd < tcp_inflight_min) 1819 bwnd = tcp_inflight_min; 1820 if (bwnd > tcp_inflight_max) 1821 bwnd = tcp_inflight_max; 1822 if ((long)bwnd < tp->t_maxseg * 2) 1823 bwnd = tp->t_maxseg * 2; 1824 tp->snd_bwnd = bwnd; 1825 } 1826 1827 #ifdef TCP_SIGNATURE 1828 /* 1829 * Callback function invoked by m_apply() to digest TCP segment data 1830 * contained within an mbuf chain. 1831 */ 1832 static int 1833 tcp_signature_apply(void *fstate, void *data, u_int len) 1834 { 1835 1836 MD5Update(fstate, (u_char *)data, len); 1837 return (0); 1838 } 1839 1840 /* 1841 * Compute TCP-MD5 hash of a TCPv4 segment. (RFC2385) 1842 * 1843 * Parameters: 1844 * m pointer to head of mbuf chain 1845 * off0 offset to TCP header within the mbuf chain 1846 * len length of TCP segment data, excluding options 1847 * optlen length of TCP segment options 1848 * buf pointer to storage for computed MD5 digest 1849 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 1850 * 1851 * We do this over ip, tcphdr, segment data, and the key in the SADB. 1852 * When called from tcp_input(), we can be sure that th_sum has been 1853 * zeroed out and verified already. 1854 * 1855 * This function is for IPv4 use only. Calling this function with an 1856 * IPv6 packet in the mbuf chain will yield undefined results. 1857 * 1858 * Return 0 if successful, otherwise return -1. 1859 * 1860 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 1861 * search with the destination IP address, and a 'magic SPI' to be 1862 * determined by the application. This is hardcoded elsewhere to 1179 1863 * right now. Another branch of this code exists which uses the SPD to 1864 * specify per-application flows but it is unstable. 1865 */ 1866 int 1867 tcp_signature_compute(struct mbuf *m, int off0, int len, int optlen, 1868 u_char *buf, u_int direction) 1869 { 1870 union sockaddr_union dst; 1871 struct ippseudo ippseudo; 1872 MD5_CTX ctx; 1873 int doff; 1874 struct ip *ip; 1875 struct ipovly *ipovly; 1876 struct secasvar *sav; 1877 struct tcphdr *th; 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 ip = mtod(m, struct ip *); 1885 bzero(&dst, sizeof(union sockaddr_union)); 1886 dst.sa.sa_len = sizeof(struct sockaddr_in); 1887 dst.sa.sa_family = AF_INET; 1888 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 1889 ip->ip_src : ip->ip_dst; 1890 1891 /* Look up an SADB entry which matches the address of the peer. */ 1892 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 1893 if (sav == NULL) { 1894 printf("%s: SADB lookup failed for %s\n", __func__, 1895 inet_ntoa(dst.sin.sin_addr)); 1896 return (EINVAL); 1897 } 1898 1899 MD5Init(&ctx); 1900 ipovly = (struct ipovly *)ip; 1901 th = (struct tcphdr *)((u_char *)ip + off0); 1902 doff = off0 + sizeof(struct tcphdr) + optlen; 1903 1904 /* 1905 * Step 1: Update MD5 hash with IP pseudo-header. 1906 * 1907 * XXX The ippseudo header MUST be digested in network byte order, 1908 * or else we'll fail the regression test. Assume all fields we've 1909 * been doing arithmetic on have been in host byte order. 1910 * XXX One cannot depend on ipovly->ih_len here. When called from 1911 * tcp_output(), the underlying ip_len member has not yet been set. 1912 */ 1913 ippseudo.ippseudo_src = ipovly->ih_src; 1914 ippseudo.ippseudo_dst = ipovly->ih_dst; 1915 ippseudo.ippseudo_pad = 0; 1916 ippseudo.ippseudo_p = IPPROTO_TCP; 1917 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + optlen); 1918 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 1919 1920 /* 1921 * Step 2: Update MD5 hash with TCP header, excluding options. 1922 * The TCP checksum must be set to zero. 1923 */ 1924 savecsum = th->th_sum; 1925 th->th_sum = 0; 1926 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 1927 th->th_sum = savecsum; 1928 1929 /* 1930 * Step 3: Update MD5 hash with TCP segment data. 1931 * Use m_apply() to avoid an early m_pullup(). 1932 */ 1933 if (len > 0) 1934 m_apply(m, doff, len, tcp_signature_apply, &ctx); 1935 1936 /* 1937 * Step 4: Update MD5 hash with shared secret. 1938 */ 1939 MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); 1940 MD5Final(buf, &ctx); 1941 1942 key_sa_recordxfer(sav, m); 1943 KEY_FREESAV(&sav); 1944 return (0); 1945 } 1946 #endif /* TCP_SIGNATURE */ 1947 1948 static int 1949 sysctl_drop(SYSCTL_HANDLER_ARGS) 1950 { 1951 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 1952 struct sockaddr_storage addrs[2]; 1953 struct inpcb *inp; 1954 struct tcpcb *tp; 1955 struct tcptw *tw; 1956 struct sockaddr_in *fin, *lin; 1957 #ifdef INET6 1958 struct sockaddr_in6 *fin6, *lin6; 1959 struct in6_addr f6, l6; 1960 #endif 1961 int error; 1962 1963 inp = NULL; 1964 fin = lin = NULL; 1965 #ifdef INET6 1966 fin6 = lin6 = NULL; 1967 #endif 1968 error = 0; 1969 1970 if (req->oldptr != NULL || req->oldlen != 0) 1971 return (EINVAL); 1972 if (req->newptr == NULL) 1973 return (EPERM); 1974 if (req->newlen < sizeof(addrs)) 1975 return (ENOMEM); 1976 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 1977 if (error) 1978 return (error); 1979 1980 switch (addrs[0].ss_family) { 1981 #ifdef INET6 1982 case AF_INET6: 1983 fin6 = (struct sockaddr_in6 *)&addrs[0]; 1984 lin6 = (struct sockaddr_in6 *)&addrs[1]; 1985 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 1986 lin6->sin6_len != sizeof(struct sockaddr_in6)) 1987 return (EINVAL); 1988 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 1989 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 1990 return (EINVAL); 1991 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 1992 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 1993 fin = (struct sockaddr_in *)&addrs[0]; 1994 lin = (struct sockaddr_in *)&addrs[1]; 1995 break; 1996 } 1997 error = sa6_embedscope(fin6, ip6_use_defzone); 1998 if (error) 1999 return (error); 2000 error = sa6_embedscope(lin6, ip6_use_defzone); 2001 if (error) 2002 return (error); 2003 break; 2004 #endif 2005 case AF_INET: 2006 fin = (struct sockaddr_in *)&addrs[0]; 2007 lin = (struct sockaddr_in *)&addrs[1]; 2008 if (fin->sin_len != sizeof(struct sockaddr_in) || 2009 lin->sin_len != sizeof(struct sockaddr_in)) 2010 return (EINVAL); 2011 break; 2012 default: 2013 return (EINVAL); 2014 } 2015 INP_INFO_WLOCK(&tcbinfo); 2016 switch (addrs[0].ss_family) { 2017 #ifdef INET6 2018 case AF_INET6: 2019 inp = in6_pcblookup_hash(&tcbinfo, &f6, fin6->sin6_port, 2020 &l6, lin6->sin6_port, 0, NULL); 2021 break; 2022 #endif 2023 case AF_INET: 2024 inp = in_pcblookup_hash(&tcbinfo, fin->sin_addr, fin->sin_port, 2025 lin->sin_addr, lin->sin_port, 0, NULL); 2026 break; 2027 } 2028 if (inp != NULL) { 2029 INP_LOCK(inp); 2030 if (inp->inp_vflag & INP_TIMEWAIT) { 2031 /* 2032 * XXXRW: There currently exists a state where an 2033 * inpcb is present, but its timewait state has been 2034 * discarded. For now, don't allow dropping of this 2035 * type of inpcb. 2036 */ 2037 tw = intotw(inp); 2038 if (tw != NULL) 2039 tcp_twclose(tw, 0); 2040 } else if (!(inp->inp_vflag & INP_DROPPED) && 2041 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2042 tp = intotcpcb(inp); 2043 tcp_drop(tp, ECONNABORTED); 2044 } 2045 INP_UNLOCK(inp); 2046 } else 2047 error = ESRCH; 2048 INP_INFO_WUNLOCK(&tcbinfo); 2049 return (error); 2050 } 2051 2052 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2053 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2054 0, sysctl_drop, "", "Drop TCP connection"); 2055 2056 /* 2057 * Generate a standardized TCP log line for use throughout the 2058 * tcp subsystem. Memory allocation is done with M_NOWAIT to 2059 * allow use in the interrupt context. 2060 * 2061 * NB: The caller MUST free(s, M_TCPLOG) the returned string. 2062 * NB: The function may return NULL if memory allocation failed. 2063 * 2064 * Due to header inclusion and ordering limitations the struct ip 2065 * and ip6_hdr pointers have to be passed as void pointers. 2066 */ 2067 char * 2068 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2069 const void *ip6hdr) 2070 { 2071 char *s, *sp; 2072 size_t size; 2073 struct ip *ip; 2074 #ifdef INET6 2075 const struct ip6_hdr *ip6; 2076 2077 ip6 = (const struct ip6_hdr *)ip6hdr; 2078 #endif /* INET6 */ 2079 ip = (struct ip *)ip4hdr; 2080 2081 /* 2082 * The log line looks like this: 2083 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>" 2084 */ 2085 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") + 2086 sizeof(PRINT_TH_FLAGS) + 1 + 2087 #ifdef INET6 2088 2 * INET6_ADDRSTRLEN; 2089 #else 2090 2 * INET_ADDRSTRLEN; 2091 #endif /* INET6 */ 2092 2093 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT); 2094 if (s == NULL) 2095 return (NULL); 2096 2097 strcat(s, "TCP: ["); 2098 sp = s + strlen(s); 2099 2100 if (inc && inc->inc_isipv6 == 0) { 2101 inet_ntoa_r(inc->inc_faddr, sp); 2102 sp = s + strlen(s); 2103 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2104 sp = s + strlen(s); 2105 inet_ntoa_r(inc->inc_laddr, sp); 2106 sp = s + strlen(s); 2107 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2108 #ifdef INET6 2109 } else if (inc) { 2110 ip6_sprintf(sp, &inc->inc6_faddr); 2111 sp = s + strlen(s); 2112 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2113 sp = s + strlen(s); 2114 ip6_sprintf(sp, &inc->inc6_laddr); 2115 sp = s + strlen(s); 2116 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2117 } else if (ip6 && th) { 2118 ip6_sprintf(sp, &ip6->ip6_src); 2119 sp = s + strlen(s); 2120 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2121 sp = s + strlen(s); 2122 ip6_sprintf(sp, &ip6->ip6_dst); 2123 sp = s + strlen(s); 2124 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2125 #endif /* INET6 */ 2126 } else if (ip && th) { 2127 inet_ntoa_r(ip->ip_src, sp); 2128 sp = s + strlen(s); 2129 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2130 sp = s + strlen(s); 2131 inet_ntoa_r(ip->ip_dst, sp); 2132 sp = s + strlen(s); 2133 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2134 } else { 2135 free(s, M_TCPLOG); 2136 return (NULL); 2137 } 2138 sp = s + strlen(s); 2139 if (th) 2140 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS); 2141 if (*(s + size - 1) != '\0') 2142 panic("%s: string too long", __func__); 2143 return (s); 2144 } 2145