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 #include "opt_tcp_sack.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/callout.h> 44 #include <sys/kernel.h> 45 #include <sys/sysctl.h> 46 #include <sys/malloc.h> 47 #include <sys/mbuf.h> 48 #ifdef INET6 49 #include <sys/domain.h> 50 #endif 51 #include <sys/priv.h> 52 #include <sys/proc.h> 53 #include <sys/socket.h> 54 #include <sys/socketvar.h> 55 #include <sys/protosw.h> 56 #include <sys/random.h> 57 58 #include <vm/uma.h> 59 60 #include <net/route.h> 61 #include <net/if.h> 62 63 #include <netinet/in.h> 64 #include <netinet/in_systm.h> 65 #include <netinet/ip.h> 66 #ifdef INET6 67 #include <netinet/ip6.h> 68 #endif 69 #include <netinet/in_pcb.h> 70 #ifdef INET6 71 #include <netinet6/in6_pcb.h> 72 #endif 73 #include <netinet/in_var.h> 74 #include <netinet/ip_var.h> 75 #ifdef INET6 76 #include <netinet6/ip6_var.h> 77 #include <netinet6/scope6_var.h> 78 #include <netinet6/nd6.h> 79 #endif 80 #include <netinet/ip_icmp.h> 81 #include <netinet/tcp.h> 82 #include <netinet/tcp_fsm.h> 83 #include <netinet/tcp_seq.h> 84 #include <netinet/tcp_timer.h> 85 #include <netinet/tcp_var.h> 86 #ifdef INET6 87 #include <netinet6/tcp6_var.h> 88 #endif 89 #include <netinet/tcpip.h> 90 #ifdef TCPDEBUG 91 #include <netinet/tcp_debug.h> 92 #endif 93 #include <netinet6/ip6protosw.h> 94 95 #ifdef IPSEC 96 #include <netinet6/ipsec.h> 97 #ifdef INET6 98 #include <netinet6/ipsec6.h> 99 #endif 100 #include <netkey/key.h> 101 #endif /*IPSEC*/ 102 103 #ifdef FAST_IPSEC 104 #include <netipsec/ipsec.h> 105 #include <netipsec/xform.h> 106 #ifdef INET6 107 #include <netipsec/ipsec6.h> 108 #endif 109 #include <netipsec/key.h> 110 #define IPSEC 111 #endif /*FAST_IPSEC*/ 112 113 #include <machine/in_cksum.h> 114 #include <sys/md5.h> 115 116 #include <security/mac/mac_framework.h> 117 118 int tcp_mssdflt = TCP_MSS; 119 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 120 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size"); 121 122 #ifdef INET6 123 int tcp_v6mssdflt = TCP6_MSS; 124 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 125 CTLFLAG_RW, &tcp_v6mssdflt , 0, 126 "Default TCP Maximum Segment Size for IPv6"); 127 #endif 128 129 /* 130 * Minimum MSS we accept and use. This prevents DoS attacks where 131 * we are forced to a ridiculous low MSS like 20 and send hundreds 132 * of packets instead of one. The effect scales with the available 133 * bandwidth and quickly saturates the CPU and network interface 134 * with packet generation and sending. Set to zero to disable MINMSS 135 * checking. This setting prevents us from sending too small packets. 136 */ 137 int tcp_minmss = TCP_MINMSS; 138 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 139 &tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 140 /* 141 * Number of TCP segments per second we accept from remote host 142 * before we start to calculate average segment size. If average 143 * segment size drops below the minimum TCP MSS we assume a DoS 144 * attack and reset+drop the connection. Care has to be taken not to 145 * set this value too small to not kill interactive type connections 146 * (telnet, SSH) which send many small packets. 147 */ 148 int tcp_minmssoverload = TCP_MINMSSOVERLOAD; 149 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmssoverload, CTLFLAG_RW, 150 &tcp_minmssoverload , 0, "Number of TCP Segments per Second allowed to" 151 "be under the MINMSS Size"); 152 153 #if 0 154 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 155 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 156 &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time"); 157 #endif 158 159 int tcp_do_rfc1323 = 1; 160 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 161 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions"); 162 163 static int tcp_tcbhashsize = 0; 164 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 165 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 166 167 static int do_tcpdrain = 1; 168 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 169 "Enable tcp_drain routine for extra help when low on mbufs"); 170 171 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 172 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 173 174 static int icmp_may_rst = 1; 175 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 176 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 177 178 static int tcp_isn_reseed_interval = 0; 179 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 180 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 181 182 static uma_zone_t tcptw_zone; 183 static int maxtcptw; 184 185 static int 186 tcptw_auto_size(void) 187 { 188 int halfrange; 189 190 /* 191 * Max out at half the ephemeral port range so that TIME_WAIT 192 * sockets don't tie up too many ephemeral ports. 193 */ 194 if (ipport_lastauto > ipport_firstauto) 195 halfrange = (ipport_lastauto - ipport_firstauto) / 2; 196 else 197 halfrange = (ipport_firstauto - ipport_lastauto) / 2; 198 /* Protect against goofy port ranges smaller than 32. */ 199 return (imin(imax(halfrange, 32), maxsockets / 5)); 200 } 201 202 static int 203 sysctl_maxtcptw(SYSCTL_HANDLER_ARGS) 204 { 205 int error, new; 206 207 if (maxtcptw == 0) 208 new = tcptw_auto_size(); 209 else 210 new = maxtcptw; 211 error = sysctl_handle_int(oidp, &new, sizeof(int), req); 212 if (error == 0 && req->newptr) 213 if (new >= 32) { 214 maxtcptw = new; 215 uma_zone_set_max(tcptw_zone, maxtcptw); 216 } 217 return (error); 218 } 219 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, maxtcptw, CTLTYPE_INT|CTLFLAG_RW, 220 &maxtcptw, 0, sysctl_maxtcptw, "IU", 221 "Maximum number of compressed TCP TIME_WAIT entries"); 222 223 static int nolocaltimewait = 0; 224 SYSCTL_INT(_net_inet_tcp, OID_AUTO, nolocaltimewait, CTLFLAG_RW, 225 &nolocaltimewait, 0, "Do not create compressed TCP TIME_WAIT entries" 226 "for local connections"); 227 228 /* 229 * TCP bandwidth limiting sysctls. Note that the default lower bound of 230 * 1024 exists only for debugging. A good production default would be 231 * something like 6100. 232 */ 233 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0, 234 "TCP inflight data limiting"); 235 236 static int tcp_inflight_enable = 1; 237 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, enable, CTLFLAG_RW, 238 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 239 240 static int tcp_inflight_debug = 0; 241 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW, 242 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 243 244 static int tcp_inflight_rttthresh; 245 SYSCTL_PROC(_net_inet_tcp_inflight, OID_AUTO, rttthresh, CTLTYPE_INT|CTLFLAG_RW, 246 &tcp_inflight_rttthresh, 0, sysctl_msec_to_ticks, "I", 247 "RTT threshold below which inflight will deactivate itself"); 248 249 static int tcp_inflight_min = 6144; 250 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, min, CTLFLAG_RW, 251 &tcp_inflight_min, 0, "Lower-bound for TCP inflight window"); 252 253 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 254 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, max, CTLFLAG_RW, 255 &tcp_inflight_max, 0, "Upper-bound for TCP inflight window"); 256 257 static int tcp_inflight_stab = 20; 258 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, stab, CTLFLAG_RW, 259 &tcp_inflight_stab, 0, "Inflight Algorithm Stabilization 20 = 2 packets"); 260 261 uma_zone_t sack_hole_zone; 262 263 static struct inpcb *tcp_notify(struct inpcb *, int); 264 static void tcp_isn_tick(void *); 265 266 /* 267 * Target size of TCP PCB hash tables. Must be a power of two. 268 * 269 * Note that this can be overridden by the kernel environment 270 * variable net.inet.tcp.tcbhashsize 271 */ 272 #ifndef TCBHASHSIZE 273 #define TCBHASHSIZE 512 274 #endif 275 276 /* 277 * XXX 278 * Callouts should be moved into struct tcp directly. They are currently 279 * separate because the tcpcb structure is exported to userland for sysctl 280 * parsing purposes, which do not know about callouts. 281 */ 282 struct tcpcb_mem { 283 struct tcpcb tcb; 284 struct callout tcpcb_mem_rexmt, tcpcb_mem_persist, tcpcb_mem_keep; 285 struct callout tcpcb_mem_2msl, tcpcb_mem_delack; 286 }; 287 288 static uma_zone_t tcpcb_zone; 289 struct callout isn_callout; 290 static struct mtx isn_mtx; 291 292 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 293 #define ISN_LOCK() mtx_lock(&isn_mtx) 294 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 295 296 /* 297 * TCP initialization. 298 */ 299 static void 300 tcp_zone_change(void *tag) 301 { 302 303 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 304 uma_zone_set_max(tcpcb_zone, maxsockets); 305 if (maxtcptw == 0) 306 uma_zone_set_max(tcptw_zone, tcptw_auto_size()); 307 } 308 309 static int 310 tcp_inpcb_init(void *mem, int size, int flags) 311 { 312 struct inpcb *inp = mem; 313 314 INP_LOCK_INIT(inp, "inp", "tcpinp"); 315 return (0); 316 } 317 318 void 319 tcp_init(void) 320 { 321 int hashsize = TCBHASHSIZE; 322 323 tcp_delacktime = TCPTV_DELACK; 324 tcp_keepinit = TCPTV_KEEP_INIT; 325 tcp_keepidle = TCPTV_KEEP_IDLE; 326 tcp_keepintvl = TCPTV_KEEPINTVL; 327 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 328 tcp_msl = TCPTV_MSL; 329 tcp_rexmit_min = TCPTV_MIN; 330 tcp_rexmit_slop = TCPTV_CPU_VAR; 331 tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 332 333 INP_INFO_LOCK_INIT(&tcbinfo, "tcp"); 334 LIST_INIT(&tcb); 335 tcbinfo.listhead = &tcb; 336 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 337 if (!powerof2(hashsize)) { 338 printf("WARNING: TCB hash size not a power of 2\n"); 339 hashsize = 512; /* safe default */ 340 } 341 tcp_tcbhashsize = hashsize; 342 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask); 343 tcbinfo.porthashbase = hashinit(hashsize, M_PCB, 344 &tcbinfo.porthashmask); 345 tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb), 346 NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 347 uma_zone_set_max(tcbinfo.ipi_zone, maxsockets); 348 #ifdef INET6 349 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 350 #else /* INET6 */ 351 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 352 #endif /* INET6 */ 353 if (max_protohdr < TCP_MINPROTOHDR) 354 max_protohdr = TCP_MINPROTOHDR; 355 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 356 panic("tcp_init"); 357 #undef TCP_MINPROTOHDR 358 /* 359 * These have to be type stable for the benefit of the timers. 360 */ 361 tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 362 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 363 uma_zone_set_max(tcpcb_zone, maxsockets); 364 tcptw_zone = uma_zcreate("tcptw", sizeof(struct tcptw), 365 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 366 TUNABLE_INT_FETCH("net.inet.tcp.maxtcptw", &maxtcptw); 367 if (maxtcptw == 0) 368 uma_zone_set_max(tcptw_zone, tcptw_auto_size()); 369 else 370 uma_zone_set_max(tcptw_zone, maxtcptw); 371 tcp_timer_init(); 372 syncache_init(); 373 tcp_hc_init(); 374 tcp_reass_init(); 375 ISN_LOCK_INIT(); 376 callout_init(&isn_callout, CALLOUT_MPSAFE); 377 tcp_isn_tick(NULL); 378 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 379 SHUTDOWN_PRI_DEFAULT); 380 sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 381 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 382 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 383 EVENTHANDLER_PRI_ANY); 384 } 385 386 void 387 tcp_fini(void *xtp) 388 { 389 390 callout_stop(&isn_callout); 391 } 392 393 /* 394 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 395 * tcp_template used to store this data in mbufs, but we now recopy it out 396 * of the tcpcb each time to conserve mbufs. 397 */ 398 void 399 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 400 { 401 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 402 403 INP_LOCK_ASSERT(inp); 404 405 #ifdef INET6 406 if ((inp->inp_vflag & INP_IPV6) != 0) { 407 struct ip6_hdr *ip6; 408 409 ip6 = (struct ip6_hdr *)ip_ptr; 410 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 411 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 412 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 413 (IPV6_VERSION & IPV6_VERSION_MASK); 414 ip6->ip6_nxt = IPPROTO_TCP; 415 ip6->ip6_plen = sizeof(struct tcphdr); 416 ip6->ip6_src = inp->in6p_laddr; 417 ip6->ip6_dst = inp->in6p_faddr; 418 } else 419 #endif 420 { 421 struct ip *ip; 422 423 ip = (struct ip *)ip_ptr; 424 ip->ip_v = IPVERSION; 425 ip->ip_hl = 5; 426 ip->ip_tos = inp->inp_ip_tos; 427 ip->ip_len = 0; 428 ip->ip_id = 0; 429 ip->ip_off = 0; 430 ip->ip_ttl = inp->inp_ip_ttl; 431 ip->ip_sum = 0; 432 ip->ip_p = IPPROTO_TCP; 433 ip->ip_src = inp->inp_laddr; 434 ip->ip_dst = inp->inp_faddr; 435 } 436 th->th_sport = inp->inp_lport; 437 th->th_dport = inp->inp_fport; 438 th->th_seq = 0; 439 th->th_ack = 0; 440 th->th_x2 = 0; 441 th->th_off = 5; 442 th->th_flags = 0; 443 th->th_win = 0; 444 th->th_urp = 0; 445 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 446 } 447 448 /* 449 * Create template to be used to send tcp packets on a connection. 450 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 451 * use for this function is in keepalives, which use tcp_respond. 452 */ 453 struct tcptemp * 454 tcpip_maketemplate(struct inpcb *inp) 455 { 456 struct mbuf *m; 457 struct tcptemp *n; 458 459 m = m_get(M_DONTWAIT, MT_DATA); 460 if (m == NULL) 461 return (0); 462 m->m_len = sizeof(struct tcptemp); 463 n = mtod(m, struct tcptemp *); 464 465 tcpip_fillheaders(inp, (void *)&n->tt_ipgen, (void *)&n->tt_t); 466 return (n); 467 } 468 469 /* 470 * Send a single message to the TCP at address specified by 471 * the given TCP/IP header. If m == NULL, then we make a copy 472 * of the tcpiphdr at ti and send directly to the addressed host. 473 * This is used to force keep alive messages out using the TCP 474 * template for a connection. If flags are given then we send 475 * a message back to the TCP which originated the * segment ti, 476 * and discard the mbuf containing it and any other attached mbufs. 477 * 478 * In any case the ack and sequence number of the transmitted 479 * segment are as specified by the parameters. 480 * 481 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 482 */ 483 void 484 tcp_respond(struct tcpcb *tp, void *ipgen, register struct tcphdr *th, 485 register struct mbuf *m, tcp_seq ack, tcp_seq seq, int flags) 486 { 487 register int tlen; 488 int win = 0; 489 struct ip *ip; 490 struct tcphdr *nth; 491 #ifdef INET6 492 struct ip6_hdr *ip6; 493 int isipv6; 494 #endif /* INET6 */ 495 int ipflags = 0; 496 struct inpcb *inp; 497 498 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 499 500 #ifdef INET6 501 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 502 ip6 = ipgen; 503 #endif /* INET6 */ 504 ip = ipgen; 505 506 if (tp != NULL) { 507 inp = tp->t_inpcb; 508 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 509 INP_INFO_WLOCK_ASSERT(&tcbinfo); 510 INP_LOCK_ASSERT(inp); 511 } else 512 inp = NULL; 513 514 if (tp != NULL) { 515 if (!(flags & TH_RST)) { 516 win = sbspace(&inp->inp_socket->so_rcv); 517 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 518 win = (long)TCP_MAXWIN << tp->rcv_scale; 519 } 520 } 521 if (m == NULL) { 522 m = m_gethdr(M_DONTWAIT, MT_DATA); 523 if (m == NULL) 524 return; 525 tlen = 0; 526 m->m_data += max_linkhdr; 527 #ifdef INET6 528 if (isipv6) { 529 bcopy((caddr_t)ip6, mtod(m, caddr_t), 530 sizeof(struct ip6_hdr)); 531 ip6 = mtod(m, struct ip6_hdr *); 532 nth = (struct tcphdr *)(ip6 + 1); 533 } else 534 #endif /* INET6 */ 535 { 536 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 537 ip = mtod(m, struct ip *); 538 nth = (struct tcphdr *)(ip + 1); 539 } 540 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 541 flags = TH_ACK; 542 } else { 543 m_freem(m->m_next); 544 m->m_next = NULL; 545 m->m_data = (caddr_t)ipgen; 546 /* m_len is set later */ 547 tlen = 0; 548 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 549 #ifdef INET6 550 if (isipv6) { 551 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 552 nth = (struct tcphdr *)(ip6 + 1); 553 } else 554 #endif /* INET6 */ 555 { 556 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 557 nth = (struct tcphdr *)(ip + 1); 558 } 559 if (th != nth) { 560 /* 561 * this is usually a case when an extension header 562 * exists between the IPv6 header and the 563 * TCP header. 564 */ 565 nth->th_sport = th->th_sport; 566 nth->th_dport = th->th_dport; 567 } 568 xchg(nth->th_dport, nth->th_sport, n_short); 569 #undef xchg 570 } 571 #ifdef INET6 572 if (isipv6) { 573 ip6->ip6_flow = 0; 574 ip6->ip6_vfc = IPV6_VERSION; 575 ip6->ip6_nxt = IPPROTO_TCP; 576 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 577 tlen)); 578 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 579 } else 580 #endif 581 { 582 tlen += sizeof (struct tcpiphdr); 583 ip->ip_len = tlen; 584 ip->ip_ttl = ip_defttl; 585 if (path_mtu_discovery) 586 ip->ip_off |= IP_DF; 587 } 588 m->m_len = tlen; 589 m->m_pkthdr.len = tlen; 590 m->m_pkthdr.rcvif = NULL; 591 #ifdef MAC 592 if (inp != NULL) { 593 /* 594 * Packet is associated with a socket, so allow the 595 * label of the response to reflect the socket label. 596 */ 597 INP_LOCK_ASSERT(inp); 598 mac_create_mbuf_from_inpcb(inp, m); 599 } else { 600 /* 601 * Packet is not associated with a socket, so possibly 602 * update the label in place. 603 */ 604 mac_reflect_mbuf_tcp(m); 605 } 606 #endif 607 nth->th_seq = htonl(seq); 608 nth->th_ack = htonl(ack); 609 nth->th_x2 = 0; 610 nth->th_off = sizeof (struct tcphdr) >> 2; 611 nth->th_flags = flags; 612 if (tp != NULL) 613 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 614 else 615 nth->th_win = htons((u_short)win); 616 nth->th_urp = 0; 617 #ifdef INET6 618 if (isipv6) { 619 nth->th_sum = 0; 620 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 621 sizeof(struct ip6_hdr), 622 tlen - sizeof(struct ip6_hdr)); 623 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 624 NULL, NULL); 625 } else 626 #endif /* INET6 */ 627 { 628 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 629 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 630 m->m_pkthdr.csum_flags = CSUM_TCP; 631 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 632 } 633 #ifdef TCPDEBUG 634 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 635 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 636 #endif 637 #ifdef INET6 638 if (isipv6) 639 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 640 else 641 #endif /* INET6 */ 642 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 643 } 644 645 /* 646 * Create a new TCP control block, making an 647 * empty reassembly queue and hooking it to the argument 648 * protocol control block. The `inp' parameter must have 649 * come from the zone allocator set up in tcp_init(). 650 */ 651 struct tcpcb * 652 tcp_newtcpcb(struct inpcb *inp) 653 { 654 struct tcpcb_mem *tm; 655 struct tcpcb *tp; 656 #ifdef INET6 657 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 658 #endif /* INET6 */ 659 660 tm = uma_zalloc(tcpcb_zone, M_NOWAIT | M_ZERO); 661 if (tm == NULL) 662 return (NULL); 663 tp = &tm->tcb; 664 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 665 tp->t_maxseg = tp->t_maxopd = 666 #ifdef INET6 667 isipv6 ? tcp_v6mssdflt : 668 #endif /* INET6 */ 669 tcp_mssdflt; 670 671 /* Set up our timeouts. */ 672 callout_init(tp->tt_rexmt = &tm->tcpcb_mem_rexmt, NET_CALLOUT_MPSAFE); 673 callout_init(tp->tt_persist = &tm->tcpcb_mem_persist, NET_CALLOUT_MPSAFE); 674 callout_init(tp->tt_keep = &tm->tcpcb_mem_keep, NET_CALLOUT_MPSAFE); 675 callout_init(tp->tt_2msl = &tm->tcpcb_mem_2msl, NET_CALLOUT_MPSAFE); 676 callout_init(tp->tt_delack = &tm->tcpcb_mem_delack, NET_CALLOUT_MPSAFE); 677 678 if (tcp_do_rfc1323) 679 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 680 tp->sack_enable = tcp_do_sack; 681 TAILQ_INIT(&tp->snd_holes); 682 tp->t_inpcb = inp; /* XXX */ 683 /* 684 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 685 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 686 * reasonable initial retransmit time. 687 */ 688 tp->t_srtt = TCPTV_SRTTBASE; 689 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 690 tp->t_rttmin = tcp_rexmit_min; 691 tp->t_rxtcur = TCPTV_RTOBASE; 692 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 693 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 694 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 695 tp->t_rcvtime = ticks; 696 tp->t_bw_rtttime = ticks; 697 /* 698 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 699 * because the socket may be bound to an IPv6 wildcard address, 700 * which may match an IPv4-mapped IPv6 address. 701 */ 702 inp->inp_ip_ttl = ip_defttl; 703 inp->inp_ppcb = tp; 704 return (tp); /* XXX */ 705 } 706 707 /* 708 * Drop a TCP connection, reporting 709 * the specified error. If connection is synchronized, 710 * then send a RST to peer. 711 */ 712 struct tcpcb * 713 tcp_drop(struct tcpcb *tp, int errno) 714 { 715 struct socket *so = tp->t_inpcb->inp_socket; 716 717 INP_INFO_WLOCK_ASSERT(&tcbinfo); 718 INP_LOCK_ASSERT(tp->t_inpcb); 719 720 if (TCPS_HAVERCVDSYN(tp->t_state)) { 721 tp->t_state = TCPS_CLOSED; 722 (void) tcp_output(tp); 723 tcpstat.tcps_drops++; 724 } else 725 tcpstat.tcps_conndrops++; 726 if (errno == ETIMEDOUT && tp->t_softerror) 727 errno = tp->t_softerror; 728 so->so_error = errno; 729 return (tcp_close(tp)); 730 } 731 732 void 733 tcp_discardcb(struct tcpcb *tp) 734 { 735 struct tseg_qent *q; 736 struct inpcb *inp = tp->t_inpcb; 737 struct socket *so = inp->inp_socket; 738 #ifdef INET6 739 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 740 #endif /* INET6 */ 741 742 INP_LOCK_ASSERT(inp); 743 744 /* 745 * Make sure that all of our timers are stopped before we 746 * delete the PCB. 747 */ 748 callout_stop(tp->tt_rexmt); 749 callout_stop(tp->tt_persist); 750 callout_stop(tp->tt_keep); 751 callout_stop(tp->tt_2msl); 752 callout_stop(tp->tt_delack); 753 754 /* 755 * If we got enough samples through the srtt filter, 756 * save the rtt and rttvar in the routing entry. 757 * 'Enough' is arbitrarily defined as 4 rtt samples. 758 * 4 samples is enough for the srtt filter to converge 759 * to within enough % of the correct value; fewer samples 760 * and we could save a bogus rtt. The danger is not high 761 * as tcp quickly recovers from everything. 762 * XXX: Works very well but needs some more statistics! 763 */ 764 if (tp->t_rttupdated >= 4) { 765 struct hc_metrics_lite metrics; 766 u_long ssthresh; 767 768 bzero(&metrics, sizeof(metrics)); 769 /* 770 * Update the ssthresh always when the conditions below 771 * are satisfied. This gives us better new start value 772 * for the congestion avoidance for new connections. 773 * ssthresh is only set if packet loss occured on a session. 774 * 775 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 776 * being torn down. Ideally this code would not use 'so'. 777 */ 778 ssthresh = tp->snd_ssthresh; 779 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 780 /* 781 * convert the limit from user data bytes to 782 * packets then to packet data bytes. 783 */ 784 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 785 if (ssthresh < 2) 786 ssthresh = 2; 787 ssthresh *= (u_long)(tp->t_maxseg + 788 #ifdef INET6 789 (isipv6 ? sizeof (struct ip6_hdr) + 790 sizeof (struct tcphdr) : 791 #endif 792 sizeof (struct tcpiphdr) 793 #ifdef INET6 794 ) 795 #endif 796 ); 797 } else 798 ssthresh = 0; 799 metrics.rmx_ssthresh = ssthresh; 800 801 metrics.rmx_rtt = tp->t_srtt; 802 metrics.rmx_rttvar = tp->t_rttvar; 803 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 804 metrics.rmx_bandwidth = tp->snd_bandwidth; 805 metrics.rmx_cwnd = tp->snd_cwnd; 806 metrics.rmx_sendpipe = 0; 807 metrics.rmx_recvpipe = 0; 808 809 tcp_hc_update(&inp->inp_inc, &metrics); 810 } 811 812 /* free the reassembly queue, if any */ 813 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) { 814 LIST_REMOVE(q, tqe_q); 815 m_freem(q->tqe_m); 816 uma_zfree(tcp_reass_zone, q); 817 tp->t_segqlen--; 818 tcp_reass_qsize--; 819 } 820 tcp_free_sackholes(tp); 821 inp->inp_ppcb = NULL; 822 tp->t_inpcb = NULL; 823 uma_zfree(tcpcb_zone, tp); 824 } 825 826 /* 827 * Attempt to close a TCP control block, marking it as dropped, and freeing 828 * the socket if we hold the only reference. 829 */ 830 struct tcpcb * 831 tcp_close(struct tcpcb *tp) 832 { 833 struct inpcb *inp = tp->t_inpcb; 834 struct socket *so; 835 836 INP_INFO_WLOCK_ASSERT(&tcbinfo); 837 INP_LOCK_ASSERT(inp); 838 839 in_pcbdrop(inp); 840 tcpstat.tcps_closed++; 841 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 842 so = inp->inp_socket; 843 soisdisconnected(so); 844 if (inp->inp_vflag & INP_SOCKREF) { 845 KASSERT(so->so_state & SS_PROTOREF, 846 ("tcp_close: !SS_PROTOREF")); 847 inp->inp_vflag &= ~INP_SOCKREF; 848 INP_UNLOCK(inp); 849 ACCEPT_LOCK(); 850 SOCK_LOCK(so); 851 so->so_state &= ~SS_PROTOREF; 852 sofree(so); 853 return (NULL); 854 } 855 return (tp); 856 } 857 858 void 859 tcp_drain(void) 860 { 861 862 if (do_tcpdrain) { 863 struct inpcb *inpb; 864 struct tcpcb *tcpb; 865 struct tseg_qent *te; 866 867 /* 868 * Walk the tcpbs, if existing, and flush the reassembly queue, 869 * if there is one... 870 * XXX: The "Net/3" implementation doesn't imply that the TCP 871 * reassembly queue should be flushed, but in a situation 872 * where we're really low on mbufs, this is potentially 873 * usefull. 874 */ 875 INP_INFO_RLOCK(&tcbinfo); 876 LIST_FOREACH(inpb, tcbinfo.listhead, inp_list) { 877 if (inpb->inp_vflag & INP_TIMEWAIT) 878 continue; 879 INP_LOCK(inpb); 880 if ((tcpb = intotcpcb(inpb)) != NULL) { 881 while ((te = LIST_FIRST(&tcpb->t_segq)) 882 != NULL) { 883 LIST_REMOVE(te, tqe_q); 884 m_freem(te->tqe_m); 885 uma_zfree(tcp_reass_zone, te); 886 tcpb->t_segqlen--; 887 tcp_reass_qsize--; 888 } 889 tcp_clean_sackreport(tcpb); 890 } 891 INP_UNLOCK(inpb); 892 } 893 INP_INFO_RUNLOCK(&tcbinfo); 894 } 895 } 896 897 /* 898 * Notify a tcp user of an asynchronous error; 899 * store error as soft error, but wake up user 900 * (for now, won't do anything until can select for soft error). 901 * 902 * Do not wake up user since there currently is no mechanism for 903 * reporting soft errors (yet - a kqueue filter may be added). 904 */ 905 static struct inpcb * 906 tcp_notify(struct inpcb *inp, int error) 907 { 908 struct tcpcb *tp; 909 910 INP_INFO_WLOCK_ASSERT(&tcbinfo); 911 INP_LOCK_ASSERT(inp); 912 913 if ((inp->inp_vflag & INP_TIMEWAIT) || 914 (inp->inp_vflag & INP_DROPPED)) 915 return (inp); 916 917 tp = intotcpcb(inp); 918 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 919 920 /* 921 * Ignore some errors if we are hooked up. 922 * If connection hasn't completed, has retransmitted several times, 923 * and receives a second error, give up now. This is better 924 * than waiting a long time to establish a connection that 925 * can never complete. 926 */ 927 if (tp->t_state == TCPS_ESTABLISHED && 928 (error == EHOSTUNREACH || error == ENETUNREACH || 929 error == EHOSTDOWN)) { 930 return (inp); 931 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 932 tp->t_softerror) { 933 tp = tcp_drop(tp, error); 934 if (tp != NULL) 935 return (inp); 936 else 937 return (NULL); 938 } else { 939 tp->t_softerror = error; 940 return (inp); 941 } 942 #if 0 943 wakeup( &so->so_timeo); 944 sorwakeup(so); 945 sowwakeup(so); 946 #endif 947 } 948 949 static int 950 tcp_pcblist(SYSCTL_HANDLER_ARGS) 951 { 952 int error, i, n; 953 struct inpcb *inp, **inp_list; 954 inp_gen_t gencnt; 955 struct xinpgen xig; 956 957 /* 958 * The process of preparing the TCB list is too time-consuming and 959 * resource-intensive to repeat twice on every request. 960 */ 961 if (req->oldptr == NULL) { 962 n = tcbinfo.ipi_count; 963 req->oldidx = 2 * (sizeof xig) 964 + (n + n/8) * sizeof(struct xtcpcb); 965 return (0); 966 } 967 968 if (req->newptr != NULL) 969 return (EPERM); 970 971 /* 972 * OK, now we're committed to doing something. 973 */ 974 INP_INFO_RLOCK(&tcbinfo); 975 gencnt = tcbinfo.ipi_gencnt; 976 n = tcbinfo.ipi_count; 977 INP_INFO_RUNLOCK(&tcbinfo); 978 979 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 980 + n * sizeof(struct xtcpcb)); 981 if (error != 0) 982 return (error); 983 984 xig.xig_len = sizeof xig; 985 xig.xig_count = n; 986 xig.xig_gen = gencnt; 987 xig.xig_sogen = so_gencnt; 988 error = SYSCTL_OUT(req, &xig, sizeof xig); 989 if (error) 990 return (error); 991 992 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 993 if (inp_list == NULL) 994 return (ENOMEM); 995 996 INP_INFO_RLOCK(&tcbinfo); 997 for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp != NULL && i < n; 998 inp = LIST_NEXT(inp, inp_list)) { 999 INP_LOCK(inp); 1000 if (inp->inp_gencnt <= gencnt) { 1001 /* 1002 * XXX: This use of cr_cansee(), introduced with 1003 * TCP state changes, is not quite right, but for 1004 * now, better than nothing. 1005 */ 1006 if (inp->inp_vflag & INP_TIMEWAIT) { 1007 if (intotw(inp) != NULL) 1008 error = cr_cansee(req->td->td_ucred, 1009 intotw(inp)->tw_cred); 1010 else 1011 error = EINVAL; /* Skip this inp. */ 1012 } else 1013 error = cr_canseesocket(req->td->td_ucred, 1014 inp->inp_socket); 1015 if (error == 0) 1016 inp_list[i++] = inp; 1017 } 1018 INP_UNLOCK(inp); 1019 } 1020 INP_INFO_RUNLOCK(&tcbinfo); 1021 n = i; 1022 1023 error = 0; 1024 for (i = 0; i < n; i++) { 1025 inp = inp_list[i]; 1026 INP_LOCK(inp); 1027 if (inp->inp_gencnt <= gencnt) { 1028 struct xtcpcb xt; 1029 void *inp_ppcb; 1030 1031 bzero(&xt, sizeof(xt)); 1032 xt.xt_len = sizeof xt; 1033 /* XXX should avoid extra copy */ 1034 bcopy(inp, &xt.xt_inp, sizeof *inp); 1035 inp_ppcb = inp->inp_ppcb; 1036 if (inp_ppcb == NULL) 1037 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1038 else if (inp->inp_vflag & INP_TIMEWAIT) { 1039 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1040 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1041 } else 1042 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1043 if (inp->inp_socket != NULL) 1044 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1045 else { 1046 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1047 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1048 } 1049 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1050 INP_UNLOCK(inp); 1051 error = SYSCTL_OUT(req, &xt, sizeof xt); 1052 } else 1053 INP_UNLOCK(inp); 1054 1055 } 1056 if (!error) { 1057 /* 1058 * Give the user an updated idea of our state. 1059 * If the generation differs from what we told 1060 * her before, she knows that something happened 1061 * while we were processing this request, and it 1062 * might be necessary to retry. 1063 */ 1064 INP_INFO_RLOCK(&tcbinfo); 1065 xig.xig_gen = tcbinfo.ipi_gencnt; 1066 xig.xig_sogen = so_gencnt; 1067 xig.xig_count = tcbinfo.ipi_count; 1068 INP_INFO_RUNLOCK(&tcbinfo); 1069 error = SYSCTL_OUT(req, &xig, sizeof xig); 1070 } 1071 free(inp_list, M_TEMP); 1072 return (error); 1073 } 1074 1075 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1076 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1077 1078 static int 1079 tcp_getcred(SYSCTL_HANDLER_ARGS) 1080 { 1081 struct xucred xuc; 1082 struct sockaddr_in addrs[2]; 1083 struct inpcb *inp; 1084 int error; 1085 1086 error = priv_check_cred(req->td->td_ucred, PRIV_NETINET_GETCRED, 1087 SUSER_ALLOWJAIL); 1088 if (error) 1089 return (error); 1090 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1091 if (error) 1092 return (error); 1093 INP_INFO_RLOCK(&tcbinfo); 1094 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 1095 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1096 if (inp == NULL) { 1097 error = ENOENT; 1098 goto outunlocked; 1099 } 1100 INP_LOCK(inp); 1101 if (inp->inp_socket == NULL) { 1102 error = ENOENT; 1103 goto out; 1104 } 1105 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1106 if (error) 1107 goto out; 1108 cru2x(inp->inp_socket->so_cred, &xuc); 1109 out: 1110 INP_UNLOCK(inp); 1111 outunlocked: 1112 INP_INFO_RUNLOCK(&tcbinfo); 1113 if (error == 0) 1114 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1115 return (error); 1116 } 1117 1118 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1119 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1120 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1121 1122 #ifdef INET6 1123 static int 1124 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1125 { 1126 struct xucred xuc; 1127 struct sockaddr_in6 addrs[2]; 1128 struct inpcb *inp; 1129 int error, mapped = 0; 1130 1131 error = priv_check_cred(req->td->td_ucred, PRIV_NETINET_GETCRED, 1132 SUSER_ALLOWJAIL); 1133 if (error) 1134 return (error); 1135 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1136 if (error) 1137 return (error); 1138 if ((error = sa6_embedscope(&addrs[0], ip6_use_defzone)) != 0 || 1139 (error = sa6_embedscope(&addrs[1], ip6_use_defzone)) != 0) { 1140 return (error); 1141 } 1142 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1143 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1144 mapped = 1; 1145 else 1146 return (EINVAL); 1147 } 1148 1149 INP_INFO_RLOCK(&tcbinfo); 1150 if (mapped == 1) 1151 inp = in_pcblookup_hash(&tcbinfo, 1152 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1153 addrs[1].sin6_port, 1154 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1155 addrs[0].sin6_port, 1156 0, NULL); 1157 else 1158 inp = in6_pcblookup_hash(&tcbinfo, 1159 &addrs[1].sin6_addr, addrs[1].sin6_port, 1160 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1161 if (inp == NULL) { 1162 error = ENOENT; 1163 goto outunlocked; 1164 } 1165 INP_LOCK(inp); 1166 if (inp->inp_socket == NULL) { 1167 error = ENOENT; 1168 goto out; 1169 } 1170 error = cr_canseesocket(req->td->td_ucred, inp->inp_socket); 1171 if (error) 1172 goto out; 1173 cru2x(inp->inp_socket->so_cred, &xuc); 1174 out: 1175 INP_UNLOCK(inp); 1176 outunlocked: 1177 INP_INFO_RUNLOCK(&tcbinfo); 1178 if (error == 0) 1179 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1180 return (error); 1181 } 1182 1183 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1184 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1185 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1186 #endif 1187 1188 1189 void 1190 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1191 { 1192 struct ip *ip = vip; 1193 struct tcphdr *th; 1194 struct in_addr faddr; 1195 struct inpcb *inp; 1196 struct tcpcb *tp; 1197 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1198 struct icmp *icp; 1199 struct in_conninfo inc; 1200 tcp_seq icmp_tcp_seq; 1201 int mtu; 1202 1203 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1204 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1205 return; 1206 1207 if (cmd == PRC_MSGSIZE) 1208 notify = tcp_mtudisc; 1209 else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1210 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1211 notify = tcp_drop_syn_sent; 1212 /* 1213 * Redirects don't need to be handled up here. 1214 */ 1215 else if (PRC_IS_REDIRECT(cmd)) 1216 return; 1217 /* 1218 * Source quench is depreciated. 1219 */ 1220 else if (cmd == PRC_QUENCH) 1221 return; 1222 /* 1223 * Hostdead is ugly because it goes linearly through all PCBs. 1224 * XXX: We never get this from ICMP, otherwise it makes an 1225 * excellent DoS attack on machines with many connections. 1226 */ 1227 else if (cmd == PRC_HOSTDEAD) 1228 ip = NULL; 1229 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1230 return; 1231 if (ip != NULL) { 1232 icp = (struct icmp *)((caddr_t)ip 1233 - offsetof(struct icmp, icmp_ip)); 1234 th = (struct tcphdr *)((caddr_t)ip 1235 + (ip->ip_hl << 2)); 1236 INP_INFO_WLOCK(&tcbinfo); 1237 inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, 1238 ip->ip_src, th->th_sport, 0, NULL); 1239 if (inp != NULL) { 1240 INP_LOCK(inp); 1241 if (!(inp->inp_vflag & INP_TIMEWAIT) && 1242 !(inp->inp_vflag & INP_DROPPED) && 1243 !(inp->inp_socket == NULL)) { 1244 icmp_tcp_seq = htonl(th->th_seq); 1245 tp = intotcpcb(inp); 1246 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1247 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1248 if (cmd == PRC_MSGSIZE) { 1249 /* 1250 * MTU discovery: 1251 * If we got a needfrag set the MTU 1252 * in the route to the suggested new 1253 * value (if given) and then notify. 1254 */ 1255 bzero(&inc, sizeof(inc)); 1256 inc.inc_flags = 0; /* IPv4 */ 1257 inc.inc_faddr = faddr; 1258 1259 mtu = ntohs(icp->icmp_nextmtu); 1260 /* 1261 * If no alternative MTU was 1262 * proposed, try the next smaller 1263 * one. ip->ip_len has already 1264 * been swapped in icmp_input(). 1265 */ 1266 if (!mtu) 1267 mtu = ip_next_mtu(ip->ip_len, 1268 1); 1269 if (mtu < max(296, (tcp_minmss) 1270 + sizeof(struct tcpiphdr))) 1271 mtu = 0; 1272 if (!mtu) 1273 mtu = tcp_mssdflt 1274 + sizeof(struct tcpiphdr); 1275 /* 1276 * Only cache the the MTU if it 1277 * is smaller than the interface 1278 * or route MTU. tcp_mtudisc() 1279 * will do right thing by itself. 1280 */ 1281 if (mtu <= tcp_maxmtu(&inc, NULL)) 1282 tcp_hc_updatemtu(&inc, mtu); 1283 } 1284 1285 inp = (*notify)(inp, inetctlerrmap[cmd]); 1286 } 1287 } 1288 if (inp != NULL) 1289 INP_UNLOCK(inp); 1290 } else { 1291 inc.inc_fport = th->th_dport; 1292 inc.inc_lport = th->th_sport; 1293 inc.inc_faddr = faddr; 1294 inc.inc_laddr = ip->ip_src; 1295 #ifdef INET6 1296 inc.inc_isipv6 = 0; 1297 #endif 1298 syncache_unreach(&inc, th); 1299 } 1300 INP_INFO_WUNLOCK(&tcbinfo); 1301 } else 1302 in_pcbnotifyall(&tcbinfo, faddr, inetctlerrmap[cmd], notify); 1303 } 1304 1305 #ifdef INET6 1306 void 1307 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1308 { 1309 struct tcphdr th; 1310 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1311 struct ip6_hdr *ip6; 1312 struct mbuf *m; 1313 struct ip6ctlparam *ip6cp = NULL; 1314 const struct sockaddr_in6 *sa6_src = NULL; 1315 int off; 1316 struct tcp_portonly { 1317 u_int16_t th_sport; 1318 u_int16_t th_dport; 1319 } *thp; 1320 1321 if (sa->sa_family != AF_INET6 || 1322 sa->sa_len != sizeof(struct sockaddr_in6)) 1323 return; 1324 1325 if (cmd == PRC_MSGSIZE) 1326 notify = tcp_mtudisc; 1327 else if (!PRC_IS_REDIRECT(cmd) && 1328 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1329 return; 1330 /* Source quench is depreciated. */ 1331 else if (cmd == PRC_QUENCH) 1332 return; 1333 1334 /* if the parameter is from icmp6, decode it. */ 1335 if (d != NULL) { 1336 ip6cp = (struct ip6ctlparam *)d; 1337 m = ip6cp->ip6c_m; 1338 ip6 = ip6cp->ip6c_ip6; 1339 off = ip6cp->ip6c_off; 1340 sa6_src = ip6cp->ip6c_src; 1341 } else { 1342 m = NULL; 1343 ip6 = NULL; 1344 off = 0; /* fool gcc */ 1345 sa6_src = &sa6_any; 1346 } 1347 1348 if (ip6 != NULL) { 1349 struct in_conninfo inc; 1350 /* 1351 * XXX: We assume that when IPV6 is non NULL, 1352 * M and OFF are valid. 1353 */ 1354 1355 /* check if we can safely examine src and dst ports */ 1356 if (m->m_pkthdr.len < off + sizeof(*thp)) 1357 return; 1358 1359 bzero(&th, sizeof(th)); 1360 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1361 1362 in6_pcbnotify(&tcbinfo, sa, th.th_dport, 1363 (struct sockaddr *)ip6cp->ip6c_src, 1364 th.th_sport, cmd, NULL, notify); 1365 1366 inc.inc_fport = th.th_dport; 1367 inc.inc_lport = th.th_sport; 1368 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1369 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1370 inc.inc_isipv6 = 1; 1371 INP_INFO_WLOCK(&tcbinfo); 1372 syncache_unreach(&inc, &th); 1373 INP_INFO_WUNLOCK(&tcbinfo); 1374 } else 1375 in6_pcbnotify(&tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1376 0, cmd, NULL, notify); 1377 } 1378 #endif /* INET6 */ 1379 1380 1381 /* 1382 * Following is where TCP initial sequence number generation occurs. 1383 * 1384 * There are two places where we must use initial sequence numbers: 1385 * 1. In SYN-ACK packets. 1386 * 2. In SYN packets. 1387 * 1388 * All ISNs for SYN-ACK packets are generated by the syncache. See 1389 * tcp_syncache.c for details. 1390 * 1391 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1392 * depends on this property. In addition, these ISNs should be 1393 * unguessable so as to prevent connection hijacking. To satisfy 1394 * the requirements of this situation, the algorithm outlined in 1395 * RFC 1948 is used, with only small modifications. 1396 * 1397 * Implementation details: 1398 * 1399 * Time is based off the system timer, and is corrected so that it 1400 * increases by one megabyte per second. This allows for proper 1401 * recycling on high speed LANs while still leaving over an hour 1402 * before rollover. 1403 * 1404 * As reading the *exact* system time is too expensive to be done 1405 * whenever setting up a TCP connection, we increment the time 1406 * offset in two ways. First, a small random positive increment 1407 * is added to isn_offset for each connection that is set up. 1408 * Second, the function tcp_isn_tick fires once per clock tick 1409 * and increments isn_offset as necessary so that sequence numbers 1410 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1411 * random positive increments serve only to ensure that the same 1412 * exact sequence number is never sent out twice (as could otherwise 1413 * happen when a port is recycled in less than the system tick 1414 * interval.) 1415 * 1416 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1417 * between seeding of isn_secret. This is normally set to zero, 1418 * as reseeding should not be necessary. 1419 * 1420 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1421 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1422 * general, this means holding an exclusive (write) lock. 1423 */ 1424 1425 #define ISN_BYTES_PER_SECOND 1048576 1426 #define ISN_STATIC_INCREMENT 4096 1427 #define ISN_RANDOM_INCREMENT (4096 - 1) 1428 1429 static u_char isn_secret[32]; 1430 static int isn_last_reseed; 1431 static u_int32_t isn_offset, isn_offset_old; 1432 static MD5_CTX isn_ctx; 1433 1434 tcp_seq 1435 tcp_new_isn(struct tcpcb *tp) 1436 { 1437 u_int32_t md5_buffer[4]; 1438 tcp_seq new_isn; 1439 1440 INP_LOCK_ASSERT(tp->t_inpcb); 1441 1442 ISN_LOCK(); 1443 /* Seed if this is the first use, reseed if requested. */ 1444 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1445 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1446 < (u_int)ticks))) { 1447 read_random(&isn_secret, sizeof(isn_secret)); 1448 isn_last_reseed = ticks; 1449 } 1450 1451 /* Compute the md5 hash and return the ISN. */ 1452 MD5Init(&isn_ctx); 1453 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1454 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1455 #ifdef INET6 1456 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1457 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1458 sizeof(struct in6_addr)); 1459 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1460 sizeof(struct in6_addr)); 1461 } else 1462 #endif 1463 { 1464 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1465 sizeof(struct in_addr)); 1466 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1467 sizeof(struct in_addr)); 1468 } 1469 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1470 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1471 new_isn = (tcp_seq) md5_buffer[0]; 1472 isn_offset += ISN_STATIC_INCREMENT + 1473 (arc4random() & ISN_RANDOM_INCREMENT); 1474 new_isn += isn_offset; 1475 ISN_UNLOCK(); 1476 return (new_isn); 1477 } 1478 1479 /* 1480 * Increment the offset to the next ISN_BYTES_PER_SECOND / hz boundary 1481 * to keep time flowing at a relatively constant rate. If the random 1482 * increments have already pushed us past the projected offset, do nothing. 1483 */ 1484 static void 1485 tcp_isn_tick(void *xtp) 1486 { 1487 u_int32_t projected_offset; 1488 1489 ISN_LOCK(); 1490 projected_offset = isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1491 1492 if (projected_offset > isn_offset) 1493 isn_offset = projected_offset; 1494 1495 isn_offset_old = isn_offset; 1496 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1497 ISN_UNLOCK(); 1498 } 1499 1500 /* 1501 * When a specific ICMP unreachable message is received and the 1502 * connection state is SYN-SENT, drop the connection. This behavior 1503 * is controlled by the icmp_may_rst sysctl. 1504 */ 1505 struct inpcb * 1506 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1507 { 1508 struct tcpcb *tp; 1509 1510 INP_INFO_WLOCK_ASSERT(&tcbinfo); 1511 INP_LOCK_ASSERT(inp); 1512 1513 if ((inp->inp_vflag & INP_TIMEWAIT) || 1514 (inp->inp_vflag & INP_DROPPED)) 1515 return (inp); 1516 1517 tp = intotcpcb(inp); 1518 if (tp->t_state != TCPS_SYN_SENT) 1519 return (inp); 1520 1521 tp = tcp_drop(tp, errno); 1522 if (tp != NULL) 1523 return (inp); 1524 else 1525 return (NULL); 1526 } 1527 1528 /* 1529 * When `need fragmentation' ICMP is received, update our idea of the MSS 1530 * based on the new value in the route. Also nudge TCP to send something, 1531 * since we know the packet we just sent was dropped. 1532 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1533 */ 1534 struct inpcb * 1535 tcp_mtudisc(struct inpcb *inp, int errno) 1536 { 1537 struct tcpcb *tp; 1538 struct socket *so = inp->inp_socket; 1539 u_int maxmtu; 1540 u_int romtu; 1541 int mss; 1542 #ifdef INET6 1543 int isipv6; 1544 #endif /* INET6 */ 1545 1546 INP_LOCK_ASSERT(inp); 1547 if ((inp->inp_vflag & INP_TIMEWAIT) || 1548 (inp->inp_vflag & INP_DROPPED)) 1549 return (inp); 1550 1551 tp = intotcpcb(inp); 1552 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1553 1554 #ifdef INET6 1555 isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; 1556 #endif 1557 maxmtu = tcp_hc_getmtu(&inp->inp_inc); /* IPv4 and IPv6 */ 1558 romtu = 1559 #ifdef INET6 1560 isipv6 ? tcp_maxmtu6(&inp->inp_inc, NULL) : 1561 #endif /* INET6 */ 1562 tcp_maxmtu(&inp->inp_inc, NULL); 1563 if (!maxmtu) 1564 maxmtu = romtu; 1565 else 1566 maxmtu = min(maxmtu, romtu); 1567 if (!maxmtu) { 1568 tp->t_maxopd = tp->t_maxseg = 1569 #ifdef INET6 1570 isipv6 ? tcp_v6mssdflt : 1571 #endif /* INET6 */ 1572 tcp_mssdflt; 1573 return (inp); 1574 } 1575 mss = maxmtu - 1576 #ifdef INET6 1577 (isipv6 ? sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1578 #endif /* INET6 */ 1579 sizeof(struct tcpiphdr) 1580 #ifdef INET6 1581 ) 1582 #endif /* INET6 */ 1583 ; 1584 1585 /* 1586 * XXX - The above conditional probably violates the TCP 1587 * spec. The problem is that, since we don't know the 1588 * other end's MSS, we are supposed to use a conservative 1589 * default. But, if we do that, then MTU discovery will 1590 * never actually take place, because the conservative 1591 * default is much less than the MTUs typically seen 1592 * on the Internet today. For the moment, we'll sweep 1593 * this under the carpet. 1594 * 1595 * The conservative default might not actually be a problem 1596 * if the only case this occurs is when sending an initial 1597 * SYN with options and data to a host we've never talked 1598 * to before. Then, they will reply with an MSS value which 1599 * will get recorded and the new parameters should get 1600 * recomputed. For Further Study. 1601 */ 1602 if (tp->t_maxopd <= mss) 1603 return (inp); 1604 tp->t_maxopd = mss; 1605 1606 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 1607 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 1608 mss -= TCPOLEN_TSTAMP_APPA; 1609 #if (MCLBYTES & (MCLBYTES - 1)) == 0 1610 if (mss > MCLBYTES) 1611 mss &= ~(MCLBYTES-1); 1612 #else 1613 if (mss > MCLBYTES) 1614 mss = mss / MCLBYTES * MCLBYTES; 1615 #endif 1616 if (so->so_snd.sb_hiwat < mss) 1617 mss = so->so_snd.sb_hiwat; 1618 1619 tp->t_maxseg = mss; 1620 1621 tcpstat.tcps_mturesent++; 1622 tp->t_rtttime = 0; 1623 tp->snd_nxt = tp->snd_una; 1624 tcp_free_sackholes(tp); 1625 tp->snd_recover = tp->snd_max; 1626 if (tp->sack_enable) 1627 EXIT_FASTRECOVERY(tp); 1628 tcp_output(tp); 1629 return (inp); 1630 } 1631 1632 /* 1633 * Look-up the routing entry to the peer of this inpcb. If no route 1634 * is found and it cannot be allocated, then return NULL. This routine 1635 * is called by TCP routines that access the rmx structure and by tcp_mss 1636 * to get the interface MTU. 1637 */ 1638 u_long 1639 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1640 { 1641 struct route sro; 1642 struct sockaddr_in *dst; 1643 struct ifnet *ifp; 1644 u_long maxmtu = 0; 1645 1646 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1647 1648 bzero(&sro, sizeof(sro)); 1649 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1650 dst = (struct sockaddr_in *)&sro.ro_dst; 1651 dst->sin_family = AF_INET; 1652 dst->sin_len = sizeof(*dst); 1653 dst->sin_addr = inc->inc_faddr; 1654 rtalloc_ign(&sro, RTF_CLONING); 1655 } 1656 if (sro.ro_rt != NULL) { 1657 ifp = sro.ro_rt->rt_ifp; 1658 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1659 maxmtu = ifp->if_mtu; 1660 else 1661 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1662 1663 /* Report additional interface capabilities. */ 1664 if (flags != NULL) { 1665 if (ifp->if_capenable & IFCAP_TSO4 && 1666 ifp->if_hwassist & CSUM_TSO) 1667 *flags |= CSUM_TSO; 1668 } 1669 RTFREE(sro.ro_rt); 1670 } 1671 return (maxmtu); 1672 } 1673 1674 #ifdef INET6 1675 u_long 1676 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1677 { 1678 struct route_in6 sro6; 1679 struct ifnet *ifp; 1680 u_long maxmtu = 0; 1681 1682 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1683 1684 bzero(&sro6, sizeof(sro6)); 1685 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1686 sro6.ro_dst.sin6_family = AF_INET6; 1687 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1688 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1689 rtalloc_ign((struct route *)&sro6, RTF_CLONING); 1690 } 1691 if (sro6.ro_rt != NULL) { 1692 ifp = sro6.ro_rt->rt_ifp; 1693 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1694 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1695 else 1696 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1697 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1698 1699 /* Report additional interface capabilities. */ 1700 if (flags != NULL) { 1701 if (ifp->if_capenable & IFCAP_TSO6 && 1702 ifp->if_hwassist & CSUM_TSO) 1703 *flags |= CSUM_TSO; 1704 } 1705 RTFREE(sro6.ro_rt); 1706 } 1707 1708 return (maxmtu); 1709 } 1710 #endif /* INET6 */ 1711 1712 #ifdef IPSEC 1713 /* compute ESP/AH header size for TCP, including outer IP header. */ 1714 size_t 1715 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1716 { 1717 struct inpcb *inp; 1718 struct mbuf *m; 1719 size_t hdrsiz; 1720 struct ip *ip; 1721 #ifdef INET6 1722 struct ip6_hdr *ip6; 1723 #endif 1724 struct tcphdr *th; 1725 1726 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1727 return (0); 1728 MGETHDR(m, M_DONTWAIT, MT_DATA); 1729 if (!m) 1730 return (0); 1731 1732 #ifdef INET6 1733 if ((inp->inp_vflag & INP_IPV6) != 0) { 1734 ip6 = mtod(m, struct ip6_hdr *); 1735 th = (struct tcphdr *)(ip6 + 1); 1736 m->m_pkthdr.len = m->m_len = 1737 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1738 tcpip_fillheaders(inp, ip6, th); 1739 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1740 } else 1741 #endif /* INET6 */ 1742 { 1743 ip = mtod(m, struct ip *); 1744 th = (struct tcphdr *)(ip + 1); 1745 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1746 tcpip_fillheaders(inp, ip, th); 1747 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1748 } 1749 1750 m_free(m); 1751 return (hdrsiz); 1752 } 1753 #endif /*IPSEC*/ 1754 1755 /* 1756 * Move a TCP connection into TIME_WAIT state. 1757 * tcbinfo is locked. 1758 * inp is locked, and is unlocked before returning. 1759 */ 1760 void 1761 tcp_twstart(struct tcpcb *tp) 1762 { 1763 struct tcptw *tw; 1764 struct inpcb *inp = tp->t_inpcb; 1765 int acknow; 1766 struct socket *so; 1767 1768 INP_INFO_WLOCK_ASSERT(&tcbinfo); /* tcp_timer_2msl_reset(). */ 1769 INP_LOCK_ASSERT(inp); 1770 1771 if (nolocaltimewait && in_localip(inp->inp_faddr)) { 1772 tp = tcp_close(tp); 1773 if (tp != NULL) 1774 INP_UNLOCK(inp); 1775 return; 1776 } 1777 1778 tw = uma_zalloc(tcptw_zone, M_NOWAIT); 1779 if (tw == NULL) { 1780 tw = tcp_timer_2msl_tw(1); 1781 if (tw == NULL) { 1782 tp = tcp_close(tp); 1783 if (tp != NULL) 1784 INP_UNLOCK(inp); 1785 return; 1786 } 1787 } 1788 tw->tw_inpcb = inp; 1789 1790 /* 1791 * Recover last window size sent. 1792 */ 1793 tw->last_win = (tp->rcv_adv - tp->rcv_nxt) >> tp->rcv_scale; 1794 1795 /* 1796 * Set t_recent if timestamps are used on the connection. 1797 */ 1798 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) == 1799 (TF_REQ_TSTMP|TF_RCVD_TSTMP)) 1800 tw->t_recent = tp->ts_recent; 1801 else 1802 tw->t_recent = 0; 1803 1804 tw->snd_nxt = tp->snd_nxt; 1805 tw->rcv_nxt = tp->rcv_nxt; 1806 tw->iss = tp->iss; 1807 tw->irs = tp->irs; 1808 tw->t_starttime = tp->t_starttime; 1809 tw->tw_time = 0; 1810 1811 /* XXX 1812 * If this code will 1813 * be used for fin-wait-2 state also, then we may need 1814 * a ts_recent from the last segment. 1815 */ 1816 acknow = tp->t_flags & TF_ACKNOW; 1817 1818 /* 1819 * First, discard tcpcb state, which includes stopping its timers and 1820 * freeing it. tcp_discardcb() used to also release the inpcb, but 1821 * that work is now done in the caller. 1822 * 1823 * Note: soisdisconnected() call used to be made in tcp_discardcb(), 1824 * and might not be needed here any longer. 1825 */ 1826 tcp_discardcb(tp); 1827 so = inp->inp_socket; 1828 soisdisconnected(so); 1829 SOCK_LOCK(so); 1830 tw->tw_cred = crhold(so->so_cred); 1831 tw->tw_so_options = so->so_options; 1832 SOCK_UNLOCK(so); 1833 if (acknow) 1834 tcp_twrespond(tw, TH_ACK); 1835 inp->inp_ppcb = tw; 1836 inp->inp_vflag |= INP_TIMEWAIT; 1837 tcp_timer_2msl_reset(tw, 0); 1838 1839 /* 1840 * If the inpcb owns the sole reference to the socket, then we can 1841 * detach and free the socket as it is not needed in time wait. 1842 */ 1843 if (inp->inp_vflag & INP_SOCKREF) { 1844 KASSERT(so->so_state & SS_PROTOREF, 1845 ("tcp_twstart: !SS_PROTOREF")); 1846 inp->inp_vflag &= ~INP_SOCKREF; 1847 INP_UNLOCK(inp); 1848 ACCEPT_LOCK(); 1849 SOCK_LOCK(so); 1850 so->so_state &= ~SS_PROTOREF; 1851 sofree(so); 1852 } else 1853 INP_UNLOCK(inp); 1854 } 1855 1856 #if 0 1857 /* 1858 * The appromixate rate of ISN increase of Microsoft TCP stacks; 1859 * the actual rate is slightly higher due to the addition of 1860 * random positive increments. 1861 * 1862 * Most other new OSes use semi-randomized ISN values, so we 1863 * do not need to worry about them. 1864 */ 1865 #define MS_ISN_BYTES_PER_SECOND 250000 1866 1867 /* 1868 * Determine if the ISN we will generate has advanced beyond the last 1869 * sequence number used by the previous connection. If so, indicate 1870 * that it is safe to recycle this tw socket by returning 1. 1871 */ 1872 int 1873 tcp_twrecycleable(struct tcptw *tw) 1874 { 1875 tcp_seq new_iss = tw->iss; 1876 tcp_seq new_irs = tw->irs; 1877 1878 INP_INFO_WLOCK_ASSERT(&tcbinfo); 1879 new_iss += (ticks - tw->t_starttime) * (ISN_BYTES_PER_SECOND / hz); 1880 new_irs += (ticks - tw->t_starttime) * (MS_ISN_BYTES_PER_SECOND / hz); 1881 1882 if (SEQ_GT(new_iss, tw->snd_nxt) && SEQ_GT(new_irs, tw->rcv_nxt)) 1883 return (1); 1884 else 1885 return (0); 1886 } 1887 #endif 1888 1889 void 1890 tcp_twclose(struct tcptw *tw, int reuse) 1891 { 1892 struct socket *so; 1893 struct inpcb *inp; 1894 1895 /* 1896 * At this point, we are in one of two situations: 1897 * 1898 * (1) We have no socket, just an inpcb<->twtcp pair. We can free 1899 * all state. 1900 * 1901 * (2) We have a socket -- if we own a reference, release it and 1902 * notify the socket layer. 1903 */ 1904 inp = tw->tw_inpcb; 1905 KASSERT((inp->inp_vflag & INP_TIMEWAIT), ("tcp_twclose: !timewait")); 1906 KASSERT(intotw(inp) == tw, ("tcp_twclose: inp_ppcb != tw")); 1907 INP_INFO_WLOCK_ASSERT(&tcbinfo); /* tcp_timer_2msl_stop(). */ 1908 INP_LOCK_ASSERT(inp); 1909 1910 tw->tw_inpcb = NULL; 1911 tcp_timer_2msl_stop(tw); 1912 inp->inp_ppcb = NULL; 1913 in_pcbdrop(inp); 1914 1915 so = inp->inp_socket; 1916 if (so != NULL) { 1917 /* 1918 * If there's a socket, handle two cases: first, we own a 1919 * strong reference, which we will now release, or we don't 1920 * in which case another reference exists (XXXRW: think 1921 * about this more), and we don't need to take action. 1922 */ 1923 if (inp->inp_vflag & INP_SOCKREF) { 1924 inp->inp_vflag &= ~INP_SOCKREF; 1925 INP_UNLOCK(inp); 1926 ACCEPT_LOCK(); 1927 SOCK_LOCK(so); 1928 KASSERT(so->so_state & SS_PROTOREF, 1929 ("tcp_twclose: INP_SOCKREF && !SS_PROTOREF")); 1930 so->so_state &= ~SS_PROTOREF; 1931 sofree(so); 1932 } else { 1933 /* 1934 * If we don't own the only reference, the socket and 1935 * inpcb need to be left around to be handled by 1936 * tcp_usr_detach() later. 1937 */ 1938 INP_UNLOCK(inp); 1939 } 1940 } else { 1941 #ifdef INET6 1942 if (inp->inp_vflag & INP_IPV6PROTO) 1943 in6_pcbfree(inp); 1944 else 1945 #endif 1946 in_pcbfree(inp); 1947 } 1948 tcpstat.tcps_closed++; 1949 crfree(tw->tw_cred); 1950 tw->tw_cred = NULL; 1951 if (reuse) 1952 return; 1953 uma_zfree(tcptw_zone, tw); 1954 } 1955 1956 int 1957 tcp_twrespond(struct tcptw *tw, int flags) 1958 { 1959 struct inpcb *inp = tw->tw_inpcb; 1960 struct tcphdr *th; 1961 struct mbuf *m; 1962 struct ip *ip = NULL; 1963 u_int8_t *optp; 1964 u_int hdrlen, optlen; 1965 int error; 1966 #ifdef INET6 1967 struct ip6_hdr *ip6 = NULL; 1968 int isipv6 = inp->inp_inc.inc_isipv6; 1969 #endif 1970 1971 INP_LOCK_ASSERT(inp); 1972 1973 m = m_gethdr(M_DONTWAIT, MT_DATA); 1974 if (m == NULL) 1975 return (ENOBUFS); 1976 m->m_data += max_linkhdr; 1977 1978 #ifdef MAC 1979 mac_create_mbuf_from_inpcb(inp, m); 1980 #endif 1981 1982 #ifdef INET6 1983 if (isipv6) { 1984 hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1985 ip6 = mtod(m, struct ip6_hdr *); 1986 th = (struct tcphdr *)(ip6 + 1); 1987 tcpip_fillheaders(inp, ip6, th); 1988 } else 1989 #endif 1990 { 1991 hdrlen = sizeof(struct tcpiphdr); 1992 ip = mtod(m, struct ip *); 1993 th = (struct tcphdr *)(ip + 1); 1994 tcpip_fillheaders(inp, ip, th); 1995 } 1996 optp = (u_int8_t *)(th + 1); 1997 1998 /* 1999 * Send a timestamp and echo-reply if both our side and our peer 2000 * have sent timestamps in our SYN's and this is not a RST. 2001 */ 2002 if (tw->t_recent && flags == TH_ACK) { 2003 u_int32_t *lp = (u_int32_t *)optp; 2004 2005 /* Form timestamp option as shown in appendix A of RFC 1323. */ 2006 *lp++ = htonl(TCPOPT_TSTAMP_HDR); 2007 *lp++ = htonl(ticks); 2008 *lp = htonl(tw->t_recent); 2009 optp += TCPOLEN_TSTAMP_APPA; 2010 } 2011 2012 optlen = optp - (u_int8_t *)(th + 1); 2013 2014 m->m_len = hdrlen + optlen; 2015 m->m_pkthdr.len = m->m_len; 2016 2017 KASSERT(max_linkhdr + m->m_len <= MHLEN, ("tcptw: mbuf too small")); 2018 2019 th->th_seq = htonl(tw->snd_nxt); 2020 th->th_ack = htonl(tw->rcv_nxt); 2021 th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; 2022 th->th_flags = flags; 2023 th->th_win = htons(tw->last_win); 2024 2025 #ifdef INET6 2026 if (isipv6) { 2027 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), 2028 sizeof(struct tcphdr) + optlen); 2029 ip6->ip6_hlim = in6_selecthlim(inp, NULL); 2030 error = ip6_output(m, inp->in6p_outputopts, NULL, 2031 (tw->tw_so_options & SO_DONTROUTE), NULL, NULL, inp); 2032 } else 2033 #endif 2034 { 2035 th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 2036 htons(sizeof(struct tcphdr) + optlen + IPPROTO_TCP)); 2037 m->m_pkthdr.csum_flags = CSUM_TCP; 2038 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 2039 ip->ip_len = m->m_pkthdr.len; 2040 if (path_mtu_discovery) 2041 ip->ip_off |= IP_DF; 2042 error = ip_output(m, inp->inp_options, NULL, 2043 ((tw->tw_so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0), 2044 NULL, inp); 2045 } 2046 if (flags & TH_ACK) 2047 tcpstat.tcps_sndacks++; 2048 else 2049 tcpstat.tcps_sndctrl++; 2050 tcpstat.tcps_sndtotal++; 2051 return (error); 2052 } 2053 2054 /* 2055 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 2056 * 2057 * This code attempts to calculate the bandwidth-delay product as a 2058 * means of determining the optimal window size to maximize bandwidth, 2059 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 2060 * routers. This code also does a fairly good job keeping RTTs in check 2061 * across slow links like modems. We implement an algorithm which is very 2062 * similar (but not meant to be) TCP/Vegas. The code operates on the 2063 * transmitter side of a TCP connection and so only effects the transmit 2064 * side of the connection. 2065 * 2066 * BACKGROUND: TCP makes no provision for the management of buffer space 2067 * at the end points or at the intermediate routers and switches. A TCP 2068 * stream, whether using NewReno or not, will eventually buffer as 2069 * many packets as it is able and the only reason this typically works is 2070 * due to the fairly small default buffers made available for a connection 2071 * (typicaly 16K or 32K). As machines use larger windows and/or window 2072 * scaling it is now fairly easy for even a single TCP connection to blow-out 2073 * all available buffer space not only on the local interface, but on 2074 * intermediate routers and switches as well. NewReno makes a misguided 2075 * attempt to 'solve' this problem by waiting for an actual failure to occur, 2076 * then backing off, then steadily increasing the window again until another 2077 * failure occurs, ad-infinitum. This results in terrible oscillation that 2078 * is only made worse as network loads increase and the idea of intentionally 2079 * blowing out network buffers is, frankly, a terrible way to manage network 2080 * resources. 2081 * 2082 * It is far better to limit the transmit window prior to the failure 2083 * condition being achieved. There are two general ways to do this: First 2084 * you can 'scan' through different transmit window sizes and locate the 2085 * point where the RTT stops increasing, indicating that you have filled the 2086 * pipe, then scan backwards until you note that RTT stops decreasing, then 2087 * repeat ad-infinitum. This method works in principle but has severe 2088 * implementation issues due to RTT variances, timer granularity, and 2089 * instability in the algorithm which can lead to many false positives and 2090 * create oscillations as well as interact badly with other TCP streams 2091 * implementing the same algorithm. 2092 * 2093 * The second method is to limit the window to the bandwidth delay product 2094 * of the link. This is the method we implement. RTT variances and our 2095 * own manipulation of the congestion window, bwnd, can potentially 2096 * destabilize the algorithm. For this reason we have to stabilize the 2097 * elements used to calculate the window. We do this by using the minimum 2098 * observed RTT, the long term average of the observed bandwidth, and 2099 * by adding two segments worth of slop. It isn't perfect but it is able 2100 * to react to changing conditions and gives us a very stable basis on 2101 * which to extend the algorithm. 2102 */ 2103 void 2104 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 2105 { 2106 u_long bw; 2107 u_long bwnd; 2108 int save_ticks; 2109 2110 INP_LOCK_ASSERT(tp->t_inpcb); 2111 2112 /* 2113 * If inflight_enable is disabled in the middle of a tcp connection, 2114 * make sure snd_bwnd is effectively disabled. 2115 */ 2116 if (tcp_inflight_enable == 0 || tp->t_rttlow < tcp_inflight_rttthresh) { 2117 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 2118 tp->snd_bandwidth = 0; 2119 return; 2120 } 2121 2122 /* 2123 * Figure out the bandwidth. Due to the tick granularity this 2124 * is a very rough number and it MUST be averaged over a fairly 2125 * long period of time. XXX we need to take into account a link 2126 * that is not using all available bandwidth, but for now our 2127 * slop will ramp us up if this case occurs and the bandwidth later 2128 * increases. 2129 * 2130 * Note: if ticks rollover 'bw' may wind up negative. We must 2131 * effectively reset t_bw_rtttime for this case. 2132 */ 2133 save_ticks = ticks; 2134 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 2135 return; 2136 2137 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 2138 (save_ticks - tp->t_bw_rtttime); 2139 tp->t_bw_rtttime = save_ticks; 2140 tp->t_bw_rtseq = ack_seq; 2141 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 2142 return; 2143 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 2144 2145 tp->snd_bandwidth = bw; 2146 2147 /* 2148 * Calculate the semi-static bandwidth delay product, plus two maximal 2149 * segments. The additional slop puts us squarely in the sweet 2150 * spot and also handles the bandwidth run-up case and stabilization. 2151 * Without the slop we could be locking ourselves into a lower 2152 * bandwidth. 2153 * 2154 * Situations Handled: 2155 * (1) Prevents over-queueing of packets on LANs, especially on 2156 * high speed LANs, allowing larger TCP buffers to be 2157 * specified, and also does a good job preventing 2158 * over-queueing of packets over choke points like modems 2159 * (at least for the transmit side). 2160 * 2161 * (2) Is able to handle changing network loads (bandwidth 2162 * drops so bwnd drops, bandwidth increases so bwnd 2163 * increases). 2164 * 2165 * (3) Theoretically should stabilize in the face of multiple 2166 * connections implementing the same algorithm (this may need 2167 * a little work). 2168 * 2169 * (4) Stability value (defaults to 20 = 2 maximal packets) can 2170 * be adjusted with a sysctl but typically only needs to be 2171 * on very slow connections. A value no smaller then 5 2172 * should be used, but only reduce this default if you have 2173 * no other choice. 2174 */ 2175 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 2176 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + tcp_inflight_stab * tp->t_maxseg / 10; 2177 #undef USERTT 2178 2179 if (tcp_inflight_debug > 0) { 2180 static int ltime; 2181 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 2182 ltime = ticks; 2183 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 2184 tp, 2185 bw, 2186 tp->t_rttbest, 2187 tp->t_srtt, 2188 bwnd 2189 ); 2190 } 2191 } 2192 if ((long)bwnd < tcp_inflight_min) 2193 bwnd = tcp_inflight_min; 2194 if (bwnd > tcp_inflight_max) 2195 bwnd = tcp_inflight_max; 2196 if ((long)bwnd < tp->t_maxseg * 2) 2197 bwnd = tp->t_maxseg * 2; 2198 tp->snd_bwnd = bwnd; 2199 } 2200 2201 #ifdef TCP_SIGNATURE 2202 /* 2203 * Callback function invoked by m_apply() to digest TCP segment data 2204 * contained within an mbuf chain. 2205 */ 2206 static int 2207 tcp_signature_apply(void *fstate, void *data, u_int len) 2208 { 2209 2210 MD5Update(fstate, (u_char *)data, len); 2211 return (0); 2212 } 2213 2214 /* 2215 * Compute TCP-MD5 hash of a TCPv4 segment. (RFC2385) 2216 * 2217 * Parameters: 2218 * m pointer to head of mbuf chain 2219 * off0 offset to TCP header within the mbuf chain 2220 * len length of TCP segment data, excluding options 2221 * optlen length of TCP segment options 2222 * buf pointer to storage for computed MD5 digest 2223 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 2224 * 2225 * We do this over ip, tcphdr, segment data, and the key in the SADB. 2226 * When called from tcp_input(), we can be sure that th_sum has been 2227 * zeroed out and verified already. 2228 * 2229 * This function is for IPv4 use only. Calling this function with an 2230 * IPv6 packet in the mbuf chain will yield undefined results. 2231 * 2232 * Return 0 if successful, otherwise return -1. 2233 * 2234 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 2235 * search with the destination IP address, and a 'magic SPI' to be 2236 * determined by the application. This is hardcoded elsewhere to 1179 2237 * right now. Another branch of this code exists which uses the SPD to 2238 * specify per-application flows but it is unstable. 2239 */ 2240 int 2241 tcp_signature_compute(struct mbuf *m, int off0, int len, int optlen, 2242 u_char *buf, u_int direction) 2243 { 2244 union sockaddr_union dst; 2245 struct ippseudo ippseudo; 2246 MD5_CTX ctx; 2247 int doff; 2248 struct ip *ip; 2249 struct ipovly *ipovly; 2250 struct secasvar *sav; 2251 struct tcphdr *th; 2252 u_short savecsum; 2253 2254 KASSERT(m != NULL, ("NULL mbuf chain")); 2255 KASSERT(buf != NULL, ("NULL signature pointer")); 2256 2257 /* Extract the destination from the IP header in the mbuf. */ 2258 ip = mtod(m, struct ip *); 2259 bzero(&dst, sizeof(union sockaddr_union)); 2260 dst.sa.sa_len = sizeof(struct sockaddr_in); 2261 dst.sa.sa_family = AF_INET; 2262 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 2263 ip->ip_src : ip->ip_dst; 2264 2265 /* Look up an SADB entry which matches the address of the peer. */ 2266 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2267 if (sav == NULL) { 2268 printf("%s: SADB lookup failed for %s\n", __func__, 2269 inet_ntoa(dst.sin.sin_addr)); 2270 return (EINVAL); 2271 } 2272 2273 MD5Init(&ctx); 2274 ipovly = (struct ipovly *)ip; 2275 th = (struct tcphdr *)((u_char *)ip + off0); 2276 doff = off0 + sizeof(struct tcphdr) + optlen; 2277 2278 /* 2279 * Step 1: Update MD5 hash with IP pseudo-header. 2280 * 2281 * XXX The ippseudo header MUST be digested in network byte order, 2282 * or else we'll fail the regression test. Assume all fields we've 2283 * been doing arithmetic on have been in host byte order. 2284 * XXX One cannot depend on ipovly->ih_len here. When called from 2285 * tcp_output(), the underlying ip_len member has not yet been set. 2286 */ 2287 ippseudo.ippseudo_src = ipovly->ih_src; 2288 ippseudo.ippseudo_dst = ipovly->ih_dst; 2289 ippseudo.ippseudo_pad = 0; 2290 ippseudo.ippseudo_p = IPPROTO_TCP; 2291 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + optlen); 2292 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2293 2294 /* 2295 * Step 2: Update MD5 hash with TCP header, excluding options. 2296 * The TCP checksum must be set to zero. 2297 */ 2298 savecsum = th->th_sum; 2299 th->th_sum = 0; 2300 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2301 th->th_sum = savecsum; 2302 2303 /* 2304 * Step 3: Update MD5 hash with TCP segment data. 2305 * Use m_apply() to avoid an early m_pullup(). 2306 */ 2307 if (len > 0) 2308 m_apply(m, doff, len, tcp_signature_apply, &ctx); 2309 2310 /* 2311 * Step 4: Update MD5 hash with shared secret. 2312 */ 2313 MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); 2314 MD5Final(buf, &ctx); 2315 2316 key_sa_recordxfer(sav, m); 2317 KEY_FREESAV(&sav); 2318 return (0); 2319 } 2320 #endif /* TCP_SIGNATURE */ 2321 2322 static int 2323 sysctl_drop(SYSCTL_HANDLER_ARGS) 2324 { 2325 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 2326 struct sockaddr_storage addrs[2]; 2327 struct inpcb *inp; 2328 struct tcpcb *tp; 2329 struct tcptw *tw; 2330 struct sockaddr_in *fin, *lin; 2331 #ifdef INET6 2332 struct sockaddr_in6 *fin6, *lin6; 2333 struct in6_addr f6, l6; 2334 #endif 2335 int error; 2336 2337 inp = NULL; 2338 fin = lin = NULL; 2339 #ifdef INET6 2340 fin6 = lin6 = NULL; 2341 #endif 2342 error = 0; 2343 2344 if (req->oldptr != NULL || req->oldlen != 0) 2345 return (EINVAL); 2346 if (req->newptr == NULL) 2347 return (EPERM); 2348 if (req->newlen < sizeof(addrs)) 2349 return (ENOMEM); 2350 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2351 if (error) 2352 return (error); 2353 2354 switch (addrs[0].ss_family) { 2355 #ifdef INET6 2356 case AF_INET6: 2357 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2358 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2359 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2360 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2361 return (EINVAL); 2362 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2363 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2364 return (EINVAL); 2365 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2366 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2367 fin = (struct sockaddr_in *)&addrs[0]; 2368 lin = (struct sockaddr_in *)&addrs[1]; 2369 break; 2370 } 2371 error = sa6_embedscope(fin6, ip6_use_defzone); 2372 if (error) 2373 return (error); 2374 error = sa6_embedscope(lin6, ip6_use_defzone); 2375 if (error) 2376 return (error); 2377 break; 2378 #endif 2379 case AF_INET: 2380 fin = (struct sockaddr_in *)&addrs[0]; 2381 lin = (struct sockaddr_in *)&addrs[1]; 2382 if (fin->sin_len != sizeof(struct sockaddr_in) || 2383 lin->sin_len != sizeof(struct sockaddr_in)) 2384 return (EINVAL); 2385 break; 2386 default: 2387 return (EINVAL); 2388 } 2389 INP_INFO_WLOCK(&tcbinfo); 2390 switch (addrs[0].ss_family) { 2391 #ifdef INET6 2392 case AF_INET6: 2393 inp = in6_pcblookup_hash(&tcbinfo, &f6, fin6->sin6_port, 2394 &l6, lin6->sin6_port, 0, NULL); 2395 break; 2396 #endif 2397 case AF_INET: 2398 inp = in_pcblookup_hash(&tcbinfo, fin->sin_addr, fin->sin_port, 2399 lin->sin_addr, lin->sin_port, 0, NULL); 2400 break; 2401 } 2402 if (inp != NULL) { 2403 INP_LOCK(inp); 2404 if (inp->inp_vflag & INP_TIMEWAIT) { 2405 /* 2406 * XXXRW: There currently exists a state where an 2407 * inpcb is present, but its timewait state has been 2408 * discarded. For now, don't allow dropping of this 2409 * type of inpcb. 2410 */ 2411 tw = intotw(inp); 2412 if (tw != NULL) 2413 tcp_twclose(tw, 0); 2414 } else if (!(inp->inp_vflag & INP_DROPPED) && 2415 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2416 tp = intotcpcb(inp); 2417 tcp_drop(tp, ECONNABORTED); 2418 } 2419 INP_UNLOCK(inp); 2420 } else 2421 error = ESRCH; 2422 INP_INFO_WUNLOCK(&tcbinfo); 2423 return (error); 2424 } 2425 2426 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2427 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2428 0, sysctl_drop, "", "Drop TCP connection"); 2429