1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_compat.h" 36 #include "opt_inet.h" 37 #include "opt_inet6.h" 38 #include "opt_ipsec.h" 39 #include "opt_mac.h" 40 #include "opt_tcpdebug.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/callout.h> 45 #include <sys/kernel.h> 46 #include <sys/sysctl.h> 47 #include <sys/malloc.h> 48 #include <sys/mbuf.h> 49 #ifdef INET6 50 #include <sys/domain.h> 51 #endif 52 #include <sys/priv.h> 53 #include <sys/proc.h> 54 #include <sys/socket.h> 55 #include <sys/socketvar.h> 56 #include <sys/protosw.h> 57 #include <sys/random.h> 58 #include <sys/vimage.h> 59 60 #include <vm/uma.h> 61 62 #include <net/route.h> 63 #include <net/if.h> 64 65 #include <netinet/in.h> 66 #include <netinet/in_systm.h> 67 #include <netinet/ip.h> 68 #ifdef INET6 69 #include <netinet/ip6.h> 70 #endif 71 #include <netinet/in_pcb.h> 72 #ifdef INET6 73 #include <netinet6/in6_pcb.h> 74 #endif 75 #include <netinet/in_var.h> 76 #include <netinet/ip_var.h> 77 #ifdef INET6 78 #include <netinet6/ip6_var.h> 79 #include <netinet6/scope6_var.h> 80 #include <netinet6/nd6.h> 81 #endif 82 #include <netinet/ip_icmp.h> 83 #include <netinet/tcp.h> 84 #include <netinet/tcp_fsm.h> 85 #include <netinet/tcp_seq.h> 86 #include <netinet/tcp_timer.h> 87 #include <netinet/tcp_var.h> 88 #include <netinet/tcp_syncache.h> 89 #include <netinet/tcp_offload.h> 90 #ifdef INET6 91 #include <netinet6/tcp6_var.h> 92 #endif 93 #include <netinet/tcpip.h> 94 #ifdef TCPDEBUG 95 #include <netinet/tcp_debug.h> 96 #endif 97 #include <netinet/vinet.h> 98 #include <netinet6/ip6protosw.h> 99 #include <netinet6/vinet6.h> 100 101 #ifdef IPSEC 102 #include <netipsec/ipsec.h> 103 #include <netipsec/xform.h> 104 #ifdef INET6 105 #include <netipsec/ipsec6.h> 106 #endif 107 #include <netipsec/key.h> 108 #include <sys/syslog.h> 109 #endif /*IPSEC*/ 110 111 #include <machine/in_cksum.h> 112 #include <sys/md5.h> 113 114 #include <security/mac/mac_framework.h> 115 116 #ifdef VIMAGE_GLOBALS 117 int tcp_mssdflt; 118 #ifdef INET6 119 int tcp_v6mssdflt; 120 #endif 121 int tcp_minmss; 122 int tcp_do_rfc1323; 123 static int icmp_may_rst; 124 static int tcp_isn_reseed_interval; 125 static int tcp_inflight_enable; 126 static int tcp_inflight_rttthresh; 127 static int tcp_inflight_min; 128 static int tcp_inflight_max; 129 static int tcp_inflight_stab; 130 #endif 131 132 static int 133 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS) 134 { 135 INIT_VNET_INET(curvnet); 136 int error, new; 137 138 new = V_tcp_mssdflt; 139 error = sysctl_handle_int(oidp, &new, 0, req); 140 if (error == 0 && req->newptr) { 141 if (new < TCP_MINMSS) 142 error = EINVAL; 143 else 144 V_tcp_mssdflt = new; 145 } 146 return (error); 147 } 148 149 SYSCTL_V_PROC(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, 150 CTLTYPE_INT|CTLFLAG_RW, tcp_mssdflt, 0, 151 &sysctl_net_inet_tcp_mss_check, "I", 152 "Default TCP Maximum Segment Size"); 153 154 #ifdef INET6 155 static int 156 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS) 157 { 158 INIT_VNET_INET(curvnet); 159 int error, new; 160 161 new = V_tcp_v6mssdflt; 162 error = sysctl_handle_int(oidp, &new, 0, req); 163 if (error == 0 && req->newptr) { 164 if (new < TCP_MINMSS) 165 error = EINVAL; 166 else 167 V_tcp_v6mssdflt = new; 168 } 169 return (error); 170 } 171 172 SYSCTL_V_PROC(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 173 CTLTYPE_INT|CTLFLAG_RW, tcp_v6mssdflt, 0, 174 &sysctl_net_inet_tcp_mss_v6_check, "I", 175 "Default TCP Maximum Segment Size for IPv6"); 176 #endif 177 178 /* 179 * Minimum MSS we accept and use. This prevents DoS attacks where 180 * we are forced to a ridiculous low MSS like 20 and send hundreds 181 * of packets instead of one. The effect scales with the available 182 * bandwidth and quickly saturates the CPU and network interface 183 * with packet generation and sending. Set to zero to disable MINMSS 184 * checking. This setting prevents us from sending too small packets. 185 */ 186 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, minmss, 187 CTLFLAG_RW, tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 188 189 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, 190 CTLFLAG_RW, tcp_do_rfc1323, 0, 191 "Enable rfc1323 (high performance TCP) extensions"); 192 193 static int tcp_log_debug = 0; 194 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW, 195 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments"); 196 197 static int tcp_tcbhashsize = 0; 198 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN, 199 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 200 201 static int do_tcpdrain = 1; 202 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 203 "Enable tcp_drain routine for extra help when low on mbufs"); 204 205 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, pcbcount, 206 CTLFLAG_RD, tcbinfo.ipi_count, 0, "Number of active PCBs"); 207 208 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, icmp_may_rst, 209 CTLFLAG_RW, icmp_may_rst, 0, 210 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 211 212 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, isn_reseed_interval, 213 CTLFLAG_RW, tcp_isn_reseed_interval, 0, 214 "Seconds between reseeding of ISN secret"); 215 216 /* 217 * TCP bandwidth limiting sysctls. Note that the default lower bound of 218 * 1024 exists only for debugging. A good production default would be 219 * something like 6100. 220 */ 221 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0, 222 "TCP inflight data limiting"); 223 224 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, enable, 225 CTLFLAG_RW, tcp_inflight_enable, 0, 226 "Enable automatic TCP inflight data limiting"); 227 228 static int tcp_inflight_debug = 0; 229 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW, 230 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 231 232 SYSCTL_V_PROC(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, rttthresh, 233 CTLTYPE_INT|CTLFLAG_RW, tcp_inflight_rttthresh, 0, sysctl_msec_to_ticks, 234 "I", "RTT threshold below which inflight will deactivate itself"); 235 236 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, min, 237 CTLFLAG_RW, tcp_inflight_min, 0, "Lower-bound for TCP inflight window"); 238 239 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, max, 240 CTLFLAG_RW, tcp_inflight_max, 0, "Upper-bound for TCP inflight window"); 241 242 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, stab, 243 CTLFLAG_RW, tcp_inflight_stab, 0, 244 "Inflight Algorithm Stabilization 20 = 2 packets"); 245 246 uma_zone_t sack_hole_zone; 247 248 static struct inpcb *tcp_notify(struct inpcb *, int); 249 static void tcp_isn_tick(void *); 250 251 /* 252 * Target size of TCP PCB hash tables. Must be a power of two. 253 * 254 * Note that this can be overridden by the kernel environment 255 * variable net.inet.tcp.tcbhashsize 256 */ 257 #ifndef TCBHASHSIZE 258 #define TCBHASHSIZE 512 259 #endif 260 261 /* 262 * XXX 263 * Callouts should be moved into struct tcp directly. They are currently 264 * separate because the tcpcb structure is exported to userland for sysctl 265 * parsing purposes, which do not know about callouts. 266 */ 267 struct tcpcb_mem { 268 struct tcpcb tcb; 269 struct tcp_timer tt; 270 }; 271 272 static uma_zone_t tcpcb_zone; 273 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers"); 274 struct callout isn_callout; 275 static struct mtx isn_mtx; 276 277 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF) 278 #define ISN_LOCK() mtx_lock(&isn_mtx) 279 #define ISN_UNLOCK() mtx_unlock(&isn_mtx) 280 281 /* 282 * TCP initialization. 283 */ 284 static void 285 tcp_zone_change(void *tag) 286 { 287 288 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 289 uma_zone_set_max(tcpcb_zone, maxsockets); 290 tcp_tw_zone_change(); 291 } 292 293 static int 294 tcp_inpcb_init(void *mem, int size, int flags) 295 { 296 struct inpcb *inp = mem; 297 298 INP_LOCK_INIT(inp, "inp", "tcpinp"); 299 return (0); 300 } 301 302 void 303 tcp_init(void) 304 { 305 INIT_VNET_INET(curvnet); 306 int hashsize; 307 308 V_blackhole = 0; 309 V_tcp_delack_enabled = 1; 310 V_drop_synfin = 0; 311 V_tcp_do_rfc3042 = 1; 312 V_tcp_do_rfc3390 = 1; 313 V_tcp_do_ecn = 0; 314 V_tcp_ecn_maxretries = 1; 315 V_tcp_insecure_rst = 0; 316 V_tcp_do_autorcvbuf = 1; 317 V_tcp_autorcvbuf_inc = 16*1024; 318 V_tcp_autorcvbuf_max = 256*1024; 319 320 V_tcp_mssdflt = TCP_MSS; 321 #ifdef INET6 322 V_tcp_v6mssdflt = TCP6_MSS; 323 #endif 324 V_tcp_minmss = TCP_MINMSS; 325 V_tcp_do_rfc1323 = 1; 326 V_icmp_may_rst = 1; 327 V_tcp_isn_reseed_interval = 0; 328 V_tcp_inflight_enable = 1; 329 V_tcp_inflight_min = 6144; 330 V_tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 331 V_tcp_inflight_stab = 20; 332 333 V_path_mtu_discovery = 1; 334 V_ss_fltsz = 1; 335 V_ss_fltsz_local = 4; 336 V_tcp_do_newreno = 1; 337 V_tcp_do_tso = 1; 338 V_tcp_do_autosndbuf = 1; 339 V_tcp_autosndbuf_inc = 8*1024; 340 V_tcp_autosndbuf_max = 256*1024; 341 342 V_nolocaltimewait = 0; 343 344 V_tcp_do_sack = 1; 345 V_tcp_sack_maxholes = 128; 346 V_tcp_sack_globalmaxholes = 65536; 347 V_tcp_sack_globalholes = 0; 348 349 tcp_delacktime = TCPTV_DELACK; 350 tcp_keepinit = TCPTV_KEEP_INIT; 351 tcp_keepidle = TCPTV_KEEP_IDLE; 352 tcp_keepintvl = TCPTV_KEEPINTVL; 353 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 354 tcp_msl = TCPTV_MSL; 355 tcp_rexmit_min = TCPTV_MIN; 356 if (tcp_rexmit_min < 1) 357 tcp_rexmit_min = 1; 358 tcp_rexmit_slop = TCPTV_CPU_VAR; 359 V_tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH; 360 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT; 361 362 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack); 363 364 INP_INFO_LOCK_INIT(&V_tcbinfo, "tcp"); 365 LIST_INIT(&V_tcb); 366 V_tcbinfo.ipi_listhead = &V_tcb; 367 hashsize = TCBHASHSIZE; 368 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 369 if (!powerof2(hashsize)) { 370 printf("WARNING: TCB hash size not a power of 2\n"); 371 hashsize = 512; /* safe default */ 372 } 373 tcp_tcbhashsize = hashsize; 374 V_tcbinfo.ipi_hashbase = hashinit(hashsize, M_PCB, 375 &V_tcbinfo.ipi_hashmask); 376 V_tcbinfo.ipi_porthashbase = hashinit(hashsize, M_PCB, 377 &V_tcbinfo.ipi_porthashmask); 378 V_tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb), 379 NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 380 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets); 381 #ifdef INET6 382 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 383 #else /* INET6 */ 384 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 385 #endif /* INET6 */ 386 if (max_protohdr < TCP_MINPROTOHDR) 387 max_protohdr = TCP_MINPROTOHDR; 388 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 389 panic("tcp_init"); 390 #undef TCP_MINPROTOHDR 391 /* 392 * These have to be type stable for the benefit of the timers. 393 */ 394 tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem), 395 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 396 uma_zone_set_max(tcpcb_zone, maxsockets); 397 tcp_tw_init(); 398 syncache_init(); 399 tcp_hc_init(); 400 tcp_reass_init(); 401 ISN_LOCK_INIT(); 402 callout_init(&isn_callout, CALLOUT_MPSAFE); 403 tcp_isn_tick(NULL); 404 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL, 405 SHUTDOWN_PRI_DEFAULT); 406 sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole), 407 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 408 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL, 409 EVENTHANDLER_PRI_ANY); 410 } 411 412 void 413 tcp_fini(void *xtp) 414 { 415 416 callout_stop(&isn_callout); 417 } 418 419 /* 420 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 421 * tcp_template used to store this data in mbufs, but we now recopy it out 422 * of the tcpcb each time to conserve mbufs. 423 */ 424 void 425 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr) 426 { 427 struct tcphdr *th = (struct tcphdr *)tcp_ptr; 428 429 INP_WLOCK_ASSERT(inp); 430 431 #ifdef INET6 432 if ((inp->inp_vflag & INP_IPV6) != 0) { 433 struct ip6_hdr *ip6; 434 435 ip6 = (struct ip6_hdr *)ip_ptr; 436 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 437 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 438 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 439 (IPV6_VERSION & IPV6_VERSION_MASK); 440 ip6->ip6_nxt = IPPROTO_TCP; 441 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 442 ip6->ip6_src = inp->in6p_laddr; 443 ip6->ip6_dst = inp->in6p_faddr; 444 } else 445 #endif 446 { 447 struct ip *ip; 448 449 ip = (struct ip *)ip_ptr; 450 ip->ip_v = IPVERSION; 451 ip->ip_hl = 5; 452 ip->ip_tos = inp->inp_ip_tos; 453 ip->ip_len = 0; 454 ip->ip_id = 0; 455 ip->ip_off = 0; 456 ip->ip_ttl = inp->inp_ip_ttl; 457 ip->ip_sum = 0; 458 ip->ip_p = IPPROTO_TCP; 459 ip->ip_src = inp->inp_laddr; 460 ip->ip_dst = inp->inp_faddr; 461 } 462 th->th_sport = inp->inp_lport; 463 th->th_dport = inp->inp_fport; 464 th->th_seq = 0; 465 th->th_ack = 0; 466 th->th_x2 = 0; 467 th->th_off = 5; 468 th->th_flags = 0; 469 th->th_win = 0; 470 th->th_urp = 0; 471 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */ 472 } 473 474 /* 475 * Create template to be used to send tcp packets on a connection. 476 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 477 * use for this function is in keepalives, which use tcp_respond. 478 */ 479 struct tcptemp * 480 tcpip_maketemplate(struct inpcb *inp) 481 { 482 struct tcptemp *t; 483 484 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT); 485 if (t == NULL) 486 return (NULL); 487 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t); 488 return (t); 489 } 490 491 /* 492 * Send a single message to the TCP at address specified by 493 * the given TCP/IP header. If m == NULL, then we make a copy 494 * of the tcpiphdr at ti and send directly to the addressed host. 495 * This is used to force keep alive messages out using the TCP 496 * template for a connection. If flags are given then we send 497 * a message back to the TCP which originated the * segment ti, 498 * and discard the mbuf containing it and any other attached mbufs. 499 * 500 * In any case the ack and sequence number of the transmitted 501 * segment are as specified by the parameters. 502 * 503 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 504 */ 505 void 506 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 507 tcp_seq ack, tcp_seq seq, int flags) 508 { 509 INIT_VNET_INET(curvnet); 510 int tlen; 511 int win = 0; 512 struct ip *ip; 513 struct tcphdr *nth; 514 #ifdef INET6 515 struct ip6_hdr *ip6; 516 int isipv6; 517 #endif /* INET6 */ 518 int ipflags = 0; 519 struct inpcb *inp; 520 521 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL")); 522 523 #ifdef INET6 524 isipv6 = ((struct ip *)ipgen)->ip_v == 6; 525 ip6 = ipgen; 526 #endif /* INET6 */ 527 ip = ipgen; 528 529 if (tp != NULL) { 530 inp = tp->t_inpcb; 531 KASSERT(inp != NULL, ("tcp control block w/o inpcb")); 532 INP_WLOCK_ASSERT(inp); 533 } else 534 inp = NULL; 535 536 if (tp != NULL) { 537 if (!(flags & TH_RST)) { 538 win = sbspace(&inp->inp_socket->so_rcv); 539 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 540 win = (long)TCP_MAXWIN << tp->rcv_scale; 541 } 542 } 543 if (m == NULL) { 544 m = m_gethdr(M_DONTWAIT, MT_DATA); 545 if (m == NULL) 546 return; 547 tlen = 0; 548 m->m_data += max_linkhdr; 549 #ifdef INET6 550 if (isipv6) { 551 bcopy((caddr_t)ip6, mtod(m, caddr_t), 552 sizeof(struct ip6_hdr)); 553 ip6 = mtod(m, struct ip6_hdr *); 554 nth = (struct tcphdr *)(ip6 + 1); 555 } else 556 #endif /* INET6 */ 557 { 558 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 559 ip = mtod(m, struct ip *); 560 nth = (struct tcphdr *)(ip + 1); 561 } 562 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr)); 563 flags = TH_ACK; 564 } else { 565 /* 566 * reuse the mbuf. 567 * XXX MRT We inherrit the FIB, which is lucky. 568 */ 569 m_freem(m->m_next); 570 m->m_next = NULL; 571 m->m_data = (caddr_t)ipgen; 572 /* m_len is set later */ 573 tlen = 0; 574 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 575 #ifdef INET6 576 if (isipv6) { 577 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 578 nth = (struct tcphdr *)(ip6 + 1); 579 } else 580 #endif /* INET6 */ 581 { 582 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 583 nth = (struct tcphdr *)(ip + 1); 584 } 585 if (th != nth) { 586 /* 587 * this is usually a case when an extension header 588 * exists between the IPv6 header and the 589 * TCP header. 590 */ 591 nth->th_sport = th->th_sport; 592 nth->th_dport = th->th_dport; 593 } 594 xchg(nth->th_dport, nth->th_sport, n_short); 595 #undef xchg 596 } 597 #ifdef INET6 598 if (isipv6) { 599 ip6->ip6_flow = 0; 600 ip6->ip6_vfc = IPV6_VERSION; 601 ip6->ip6_nxt = IPPROTO_TCP; 602 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) + 603 tlen)); 604 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr); 605 } else 606 #endif 607 { 608 tlen += sizeof (struct tcpiphdr); 609 ip->ip_len = tlen; 610 ip->ip_ttl = V_ip_defttl; 611 if (V_path_mtu_discovery) 612 ip->ip_off |= IP_DF; 613 } 614 m->m_len = tlen; 615 m->m_pkthdr.len = tlen; 616 m->m_pkthdr.rcvif = NULL; 617 #ifdef MAC 618 if (inp != NULL) { 619 /* 620 * Packet is associated with a socket, so allow the 621 * label of the response to reflect the socket label. 622 */ 623 INP_WLOCK_ASSERT(inp); 624 mac_inpcb_create_mbuf(inp, m); 625 } else { 626 /* 627 * Packet is not associated with a socket, so possibly 628 * update the label in place. 629 */ 630 mac_netinet_tcp_reply(m); 631 } 632 #endif 633 nth->th_seq = htonl(seq); 634 nth->th_ack = htonl(ack); 635 nth->th_x2 = 0; 636 nth->th_off = sizeof (struct tcphdr) >> 2; 637 nth->th_flags = flags; 638 if (tp != NULL) 639 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 640 else 641 nth->th_win = htons((u_short)win); 642 nth->th_urp = 0; 643 #ifdef INET6 644 if (isipv6) { 645 nth->th_sum = 0; 646 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 647 sizeof(struct ip6_hdr), 648 tlen - sizeof(struct ip6_hdr)); 649 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb : 650 NULL, NULL); 651 } else 652 #endif /* INET6 */ 653 { 654 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 655 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 656 m->m_pkthdr.csum_flags = CSUM_TCP; 657 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 658 } 659 #ifdef TCPDEBUG 660 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG)) 661 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 662 #endif 663 #ifdef INET6 664 if (isipv6) 665 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp); 666 else 667 #endif /* INET6 */ 668 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp); 669 } 670 671 /* 672 * Create a new TCP control block, making an 673 * empty reassembly queue and hooking it to the argument 674 * protocol control block. The `inp' parameter must have 675 * come from the zone allocator set up in tcp_init(). 676 */ 677 struct tcpcb * 678 tcp_newtcpcb(struct inpcb *inp) 679 { 680 INIT_VNET_INET(inp->inp_vnet); 681 struct tcpcb_mem *tm; 682 struct tcpcb *tp; 683 #ifdef INET6 684 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 685 #endif /* INET6 */ 686 687 tm = uma_zalloc(tcpcb_zone, M_NOWAIT | M_ZERO); 688 if (tm == NULL) 689 return (NULL); 690 tp = &tm->tcb; 691 tp->t_timers = &tm->tt; 692 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ 693 tp->t_maxseg = tp->t_maxopd = 694 #ifdef INET6 695 isipv6 ? V_tcp_v6mssdflt : 696 #endif /* INET6 */ 697 V_tcp_mssdflt; 698 699 /* Set up our timeouts. */ 700 callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE); 701 callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE); 702 callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE); 703 callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE); 704 callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE); 705 706 if (V_tcp_do_rfc1323) 707 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 708 if (V_tcp_do_sack) 709 tp->t_flags |= TF_SACK_PERMIT; 710 TAILQ_INIT(&tp->snd_holes); 711 tp->t_inpcb = inp; /* XXX */ 712 /* 713 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 714 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 715 * reasonable initial retransmit time. 716 */ 717 tp->t_srtt = TCPTV_SRTTBASE; 718 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 719 tp->t_rttmin = tcp_rexmit_min; 720 tp->t_rxtcur = TCPTV_RTOBASE; 721 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 722 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 723 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 724 tp->t_rcvtime = ticks; 725 tp->t_bw_rtttime = ticks; 726 /* 727 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 728 * because the socket may be bound to an IPv6 wildcard address, 729 * which may match an IPv4-mapped IPv6 address. 730 */ 731 inp->inp_ip_ttl = V_ip_defttl; 732 inp->inp_ppcb = tp; 733 return (tp); /* XXX */ 734 } 735 736 /* 737 * Drop a TCP connection, reporting 738 * the specified error. If connection is synchronized, 739 * then send a RST to peer. 740 */ 741 struct tcpcb * 742 tcp_drop(struct tcpcb *tp, int errno) 743 { 744 INIT_VNET_INET(tp->t_inpcb->inp_vnet); 745 struct socket *so = tp->t_inpcb->inp_socket; 746 747 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 748 INP_WLOCK_ASSERT(tp->t_inpcb); 749 750 if (TCPS_HAVERCVDSYN(tp->t_state)) { 751 tp->t_state = TCPS_CLOSED; 752 (void) tcp_output_reset(tp); 753 V_tcpstat.tcps_drops++; 754 } else 755 V_tcpstat.tcps_conndrops++; 756 if (errno == ETIMEDOUT && tp->t_softerror) 757 errno = tp->t_softerror; 758 so->so_error = errno; 759 return (tcp_close(tp)); 760 } 761 762 void 763 tcp_discardcb(struct tcpcb *tp) 764 { 765 INIT_VNET_INET(tp->t_vnet); 766 struct tseg_qent *q; 767 struct inpcb *inp = tp->t_inpcb; 768 struct socket *so = inp->inp_socket; 769 #ifdef INET6 770 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; 771 #endif /* INET6 */ 772 773 INP_WLOCK_ASSERT(inp); 774 775 /* 776 * Make sure that all of our timers are stopped before we 777 * delete the PCB. 778 */ 779 callout_stop(&tp->t_timers->tt_rexmt); 780 callout_stop(&tp->t_timers->tt_persist); 781 callout_stop(&tp->t_timers->tt_keep); 782 callout_stop(&tp->t_timers->tt_2msl); 783 callout_stop(&tp->t_timers->tt_delack); 784 785 /* 786 * If we got enough samples through the srtt filter, 787 * save the rtt and rttvar in the routing entry. 788 * 'Enough' is arbitrarily defined as 4 rtt samples. 789 * 4 samples is enough for the srtt filter to converge 790 * to within enough % of the correct value; fewer samples 791 * and we could save a bogus rtt. The danger is not high 792 * as tcp quickly recovers from everything. 793 * XXX: Works very well but needs some more statistics! 794 */ 795 if (tp->t_rttupdated >= 4) { 796 struct hc_metrics_lite metrics; 797 u_long ssthresh; 798 799 bzero(&metrics, sizeof(metrics)); 800 /* 801 * Update the ssthresh always when the conditions below 802 * are satisfied. This gives us better new start value 803 * for the congestion avoidance for new connections. 804 * ssthresh is only set if packet loss occured on a session. 805 * 806 * XXXRW: 'so' may be NULL here, and/or socket buffer may be 807 * being torn down. Ideally this code would not use 'so'. 808 */ 809 ssthresh = tp->snd_ssthresh; 810 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) { 811 /* 812 * convert the limit from user data bytes to 813 * packets then to packet data bytes. 814 */ 815 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg; 816 if (ssthresh < 2) 817 ssthresh = 2; 818 ssthresh *= (u_long)(tp->t_maxseg + 819 #ifdef INET6 820 (isipv6 ? sizeof (struct ip6_hdr) + 821 sizeof (struct tcphdr) : 822 #endif 823 sizeof (struct tcpiphdr) 824 #ifdef INET6 825 ) 826 #endif 827 ); 828 } else 829 ssthresh = 0; 830 metrics.rmx_ssthresh = ssthresh; 831 832 metrics.rmx_rtt = tp->t_srtt; 833 metrics.rmx_rttvar = tp->t_rttvar; 834 /* XXX: This wraps if the pipe is more than 4 Gbit per second */ 835 metrics.rmx_bandwidth = tp->snd_bandwidth; 836 metrics.rmx_cwnd = tp->snd_cwnd; 837 metrics.rmx_sendpipe = 0; 838 metrics.rmx_recvpipe = 0; 839 840 tcp_hc_update(&inp->inp_inc, &metrics); 841 } 842 843 /* free the reassembly queue, if any */ 844 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) { 845 LIST_REMOVE(q, tqe_q); 846 m_freem(q->tqe_m); 847 uma_zfree(tcp_reass_zone, q); 848 tp->t_segqlen--; 849 V_tcp_reass_qsize--; 850 } 851 /* Disconnect offload device, if any. */ 852 tcp_offload_detach(tp); 853 854 tcp_free_sackholes(tp); 855 inp->inp_ppcb = NULL; 856 tp->t_inpcb = NULL; 857 uma_zfree(tcpcb_zone, tp); 858 } 859 860 /* 861 * Attempt to close a TCP control block, marking it as dropped, and freeing 862 * the socket if we hold the only reference. 863 */ 864 struct tcpcb * 865 tcp_close(struct tcpcb *tp) 866 { 867 INIT_VNET_INET(tp->t_inpcb->inp_vnet); 868 struct inpcb *inp = tp->t_inpcb; 869 struct socket *so; 870 871 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 872 INP_WLOCK_ASSERT(inp); 873 874 /* Notify any offload devices of listener close */ 875 if (tp->t_state == TCPS_LISTEN) 876 tcp_offload_listen_close(tp); 877 in_pcbdrop(inp); 878 V_tcpstat.tcps_closed++; 879 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL")); 880 so = inp->inp_socket; 881 soisdisconnected(so); 882 if (inp->inp_vflag & INP_SOCKREF) { 883 KASSERT(so->so_state & SS_PROTOREF, 884 ("tcp_close: !SS_PROTOREF")); 885 inp->inp_vflag &= ~INP_SOCKREF; 886 INP_WUNLOCK(inp); 887 ACCEPT_LOCK(); 888 SOCK_LOCK(so); 889 so->so_state &= ~SS_PROTOREF; 890 sofree(so); 891 return (NULL); 892 } 893 return (tp); 894 } 895 896 void 897 tcp_drain(void) 898 { 899 VNET_ITERATOR_DECL(vnet_iter); 900 901 if (!do_tcpdrain) 902 return; 903 904 VNET_LIST_RLOCK(); 905 VNET_FOREACH(vnet_iter) { 906 CURVNET_SET(vnet_iter); 907 INIT_VNET_INET(vnet_iter); 908 struct inpcb *inpb; 909 struct tcpcb *tcpb; 910 struct tseg_qent *te; 911 912 /* 913 * Walk the tcpbs, if existing, and flush the reassembly queue, 914 * if there is one... 915 * XXX: The "Net/3" implementation doesn't imply that the TCP 916 * reassembly queue should be flushed, but in a situation 917 * where we're really low on mbufs, this is potentially 918 * usefull. 919 */ 920 INP_INFO_RLOCK(&V_tcbinfo); 921 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) { 922 if (inpb->inp_vflag & INP_TIMEWAIT) 923 continue; 924 INP_WLOCK(inpb); 925 if ((tcpb = intotcpcb(inpb)) != NULL) { 926 while ((te = LIST_FIRST(&tcpb->t_segq)) 927 != NULL) { 928 LIST_REMOVE(te, tqe_q); 929 m_freem(te->tqe_m); 930 uma_zfree(tcp_reass_zone, te); 931 tcpb->t_segqlen--; 932 V_tcp_reass_qsize--; 933 } 934 tcp_clean_sackreport(tcpb); 935 } 936 INP_WUNLOCK(inpb); 937 } 938 INP_INFO_RUNLOCK(&V_tcbinfo); 939 CURVNET_RESTORE(); 940 } 941 VNET_LIST_RUNLOCK(); 942 } 943 944 /* 945 * Notify a tcp user of an asynchronous error; 946 * store error as soft error, but wake up user 947 * (for now, won't do anything until can select for soft error). 948 * 949 * Do not wake up user since there currently is no mechanism for 950 * reporting soft errors (yet - a kqueue filter may be added). 951 */ 952 static struct inpcb * 953 tcp_notify(struct inpcb *inp, int error) 954 { 955 struct tcpcb *tp; 956 #ifdef INVARIANTS 957 INIT_VNET_INET(inp->inp_vnet); /* V_tcbinfo WLOCK ASSERT */ 958 #endif 959 960 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 961 INP_WLOCK_ASSERT(inp); 962 963 if ((inp->inp_vflag & INP_TIMEWAIT) || 964 (inp->inp_vflag & INP_DROPPED)) 965 return (inp); 966 967 tp = intotcpcb(inp); 968 KASSERT(tp != NULL, ("tcp_notify: tp == NULL")); 969 970 /* 971 * Ignore some errors if we are hooked up. 972 * If connection hasn't completed, has retransmitted several times, 973 * and receives a second error, give up now. This is better 974 * than waiting a long time to establish a connection that 975 * can never complete. 976 */ 977 if (tp->t_state == TCPS_ESTABLISHED && 978 (error == EHOSTUNREACH || error == ENETUNREACH || 979 error == EHOSTDOWN)) { 980 return (inp); 981 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 982 tp->t_softerror) { 983 tp = tcp_drop(tp, error); 984 if (tp != NULL) 985 return (inp); 986 else 987 return (NULL); 988 } else { 989 tp->t_softerror = error; 990 return (inp); 991 } 992 #if 0 993 wakeup( &so->so_timeo); 994 sorwakeup(so); 995 sowwakeup(so); 996 #endif 997 } 998 999 static int 1000 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1001 { 1002 INIT_VNET_INET(curvnet); 1003 int error, i, m, n, pcb_count; 1004 struct inpcb *inp, **inp_list; 1005 inp_gen_t gencnt; 1006 struct xinpgen xig; 1007 1008 /* 1009 * The process of preparing the TCB list is too time-consuming and 1010 * resource-intensive to repeat twice on every request. 1011 */ 1012 if (req->oldptr == NULL) { 1013 m = syncache_pcbcount(); 1014 n = V_tcbinfo.ipi_count; 1015 req->oldidx = 2 * (sizeof xig) 1016 + ((m + n) + n/8) * sizeof(struct xtcpcb); 1017 return (0); 1018 } 1019 1020 if (req->newptr != NULL) 1021 return (EPERM); 1022 1023 /* 1024 * OK, now we're committed to doing something. 1025 */ 1026 INP_INFO_RLOCK(&V_tcbinfo); 1027 gencnt = V_tcbinfo.ipi_gencnt; 1028 n = V_tcbinfo.ipi_count; 1029 INP_INFO_RUNLOCK(&V_tcbinfo); 1030 1031 m = syncache_pcbcount(); 1032 1033 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig) 1034 + (n + m) * sizeof(struct xtcpcb)); 1035 if (error != 0) 1036 return (error); 1037 1038 xig.xig_len = sizeof xig; 1039 xig.xig_count = n + m; 1040 xig.xig_gen = gencnt; 1041 xig.xig_sogen = so_gencnt; 1042 error = SYSCTL_OUT(req, &xig, sizeof xig); 1043 if (error) 1044 return (error); 1045 1046 error = syncache_pcblist(req, m, &pcb_count); 1047 if (error) 1048 return (error); 1049 1050 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 1051 if (inp_list == NULL) 1052 return (ENOMEM); 1053 1054 INP_INFO_RLOCK(&V_tcbinfo); 1055 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0; 1056 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) { 1057 INP_RLOCK(inp); 1058 if (inp->inp_gencnt <= gencnt) { 1059 /* 1060 * XXX: This use of cr_cansee(), introduced with 1061 * TCP state changes, is not quite right, but for 1062 * now, better than nothing. 1063 */ 1064 if (inp->inp_vflag & INP_TIMEWAIT) { 1065 if (intotw(inp) != NULL) 1066 error = cr_cansee(req->td->td_ucred, 1067 intotw(inp)->tw_cred); 1068 else 1069 error = EINVAL; /* Skip this inp. */ 1070 } else 1071 error = cr_canseeinpcb(req->td->td_ucred, inp); 1072 if (error == 0) 1073 inp_list[i++] = inp; 1074 } 1075 INP_RUNLOCK(inp); 1076 } 1077 INP_INFO_RUNLOCK(&V_tcbinfo); 1078 n = i; 1079 1080 error = 0; 1081 for (i = 0; i < n; i++) { 1082 inp = inp_list[i]; 1083 INP_RLOCK(inp); 1084 if (inp->inp_gencnt <= gencnt) { 1085 struct xtcpcb xt; 1086 void *inp_ppcb; 1087 1088 bzero(&xt, sizeof(xt)); 1089 xt.xt_len = sizeof xt; 1090 /* XXX should avoid extra copy */ 1091 bcopy(inp, &xt.xt_inp, sizeof *inp); 1092 inp_ppcb = inp->inp_ppcb; 1093 if (inp_ppcb == NULL) 1094 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1095 else if (inp->inp_vflag & INP_TIMEWAIT) { 1096 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 1097 xt.xt_tp.t_state = TCPS_TIME_WAIT; 1098 } else 1099 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1100 if (inp->inp_socket != NULL) 1101 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1102 else { 1103 bzero(&xt.xt_socket, sizeof xt.xt_socket); 1104 xt.xt_socket.xso_protocol = IPPROTO_TCP; 1105 } 1106 xt.xt_inp.inp_gencnt = inp->inp_gencnt; 1107 INP_RUNLOCK(inp); 1108 error = SYSCTL_OUT(req, &xt, sizeof xt); 1109 } else 1110 INP_RUNLOCK(inp); 1111 1112 } 1113 if (!error) { 1114 /* 1115 * Give the user an updated idea of our state. 1116 * If the generation differs from what we told 1117 * her before, she knows that something happened 1118 * while we were processing this request, and it 1119 * might be necessary to retry. 1120 */ 1121 INP_INFO_RLOCK(&V_tcbinfo); 1122 xig.xig_gen = V_tcbinfo.ipi_gencnt; 1123 xig.xig_sogen = so_gencnt; 1124 xig.xig_count = V_tcbinfo.ipi_count + pcb_count; 1125 INP_INFO_RUNLOCK(&V_tcbinfo); 1126 error = SYSCTL_OUT(req, &xig, sizeof xig); 1127 } 1128 free(inp_list, M_TEMP); 1129 return (error); 1130 } 1131 1132 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1133 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1134 1135 static int 1136 tcp_getcred(SYSCTL_HANDLER_ARGS) 1137 { 1138 INIT_VNET_INET(curvnet); 1139 struct xucred xuc; 1140 struct sockaddr_in addrs[2]; 1141 struct inpcb *inp; 1142 int error; 1143 1144 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1145 if (error) 1146 return (error); 1147 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1148 if (error) 1149 return (error); 1150 INP_INFO_RLOCK(&V_tcbinfo); 1151 inp = in_pcblookup_hash(&V_tcbinfo, addrs[1].sin_addr, 1152 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1153 if (inp != NULL) { 1154 INP_RLOCK(inp); 1155 INP_INFO_RUNLOCK(&V_tcbinfo); 1156 if (inp->inp_socket == NULL) 1157 error = ENOENT; 1158 if (error == 0) 1159 error = cr_canseeinpcb(req->td->td_ucred, inp); 1160 if (error == 0) 1161 cru2x(inp->inp_cred, &xuc); 1162 INP_RUNLOCK(inp); 1163 } else { 1164 INP_INFO_RUNLOCK(&V_tcbinfo); 1165 error = ENOENT; 1166 } 1167 if (error == 0) 1168 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1169 return (error); 1170 } 1171 1172 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, 1173 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1174 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection"); 1175 1176 #ifdef INET6 1177 static int 1178 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1179 { 1180 INIT_VNET_INET(curvnet); 1181 INIT_VNET_INET6(curvnet); 1182 struct xucred xuc; 1183 struct sockaddr_in6 addrs[2]; 1184 struct inpcb *inp; 1185 int error, mapped = 0; 1186 1187 error = priv_check(req->td, PRIV_NETINET_GETCRED); 1188 if (error) 1189 return (error); 1190 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 1191 if (error) 1192 return (error); 1193 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 || 1194 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) { 1195 return (error); 1196 } 1197 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1198 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1199 mapped = 1; 1200 else 1201 return (EINVAL); 1202 } 1203 1204 INP_INFO_RLOCK(&V_tcbinfo); 1205 if (mapped == 1) 1206 inp = in_pcblookup_hash(&V_tcbinfo, 1207 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1208 addrs[1].sin6_port, 1209 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1210 addrs[0].sin6_port, 1211 0, NULL); 1212 else 1213 inp = in6_pcblookup_hash(&V_tcbinfo, 1214 &addrs[1].sin6_addr, addrs[1].sin6_port, 1215 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL); 1216 if (inp != NULL) { 1217 INP_RLOCK(inp); 1218 INP_INFO_RUNLOCK(&V_tcbinfo); 1219 if (inp->inp_socket == NULL) 1220 error = ENOENT; 1221 if (error == 0) 1222 error = cr_canseeinpcb(req->td->td_ucred, inp); 1223 if (error == 0) 1224 cru2x(inp->inp_cred, &xuc); 1225 INP_RUNLOCK(inp); 1226 } else { 1227 INP_INFO_RUNLOCK(&V_tcbinfo); 1228 error = ENOENT; 1229 } 1230 if (error == 0) 1231 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred)); 1232 return (error); 1233 } 1234 1235 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, 1236 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0, 1237 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection"); 1238 #endif 1239 1240 1241 void 1242 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1243 { 1244 INIT_VNET_INET(curvnet); 1245 struct ip *ip = vip; 1246 struct tcphdr *th; 1247 struct in_addr faddr; 1248 struct inpcb *inp; 1249 struct tcpcb *tp; 1250 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1251 struct icmp *icp; 1252 struct in_conninfo inc; 1253 tcp_seq icmp_tcp_seq; 1254 int mtu; 1255 1256 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1257 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1258 return; 1259 1260 if (cmd == PRC_MSGSIZE) 1261 notify = tcp_mtudisc; 1262 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || 1263 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip) 1264 notify = tcp_drop_syn_sent; 1265 /* 1266 * Redirects don't need to be handled up here. 1267 */ 1268 else if (PRC_IS_REDIRECT(cmd)) 1269 return; 1270 /* 1271 * Source quench is depreciated. 1272 */ 1273 else if (cmd == PRC_QUENCH) 1274 return; 1275 /* 1276 * Hostdead is ugly because it goes linearly through all PCBs. 1277 * XXX: We never get this from ICMP, otherwise it makes an 1278 * excellent DoS attack on machines with many connections. 1279 */ 1280 else if (cmd == PRC_HOSTDEAD) 1281 ip = NULL; 1282 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) 1283 return; 1284 if (ip != NULL) { 1285 icp = (struct icmp *)((caddr_t)ip 1286 - offsetof(struct icmp, icmp_ip)); 1287 th = (struct tcphdr *)((caddr_t)ip 1288 + (ip->ip_hl << 2)); 1289 INP_INFO_WLOCK(&V_tcbinfo); 1290 inp = in_pcblookup_hash(&V_tcbinfo, faddr, th->th_dport, 1291 ip->ip_src, th->th_sport, 0, NULL); 1292 if (inp != NULL) { 1293 INP_WLOCK(inp); 1294 if (!(inp->inp_vflag & INP_TIMEWAIT) && 1295 !(inp->inp_vflag & INP_DROPPED) && 1296 !(inp->inp_socket == NULL)) { 1297 icmp_tcp_seq = htonl(th->th_seq); 1298 tp = intotcpcb(inp); 1299 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) && 1300 SEQ_LT(icmp_tcp_seq, tp->snd_max)) { 1301 if (cmd == PRC_MSGSIZE) { 1302 /* 1303 * MTU discovery: 1304 * If we got a needfrag set the MTU 1305 * in the route to the suggested new 1306 * value (if given) and then notify. 1307 */ 1308 bzero(&inc, sizeof(inc)); 1309 inc.inc_flags = 0; /* IPv4 */ 1310 inc.inc_faddr = faddr; 1311 inc.inc_fibnum = 1312 inp->inp_inc.inc_fibnum; 1313 1314 mtu = ntohs(icp->icmp_nextmtu); 1315 /* 1316 * If no alternative MTU was 1317 * proposed, try the next smaller 1318 * one. ip->ip_len has already 1319 * been swapped in icmp_input(). 1320 */ 1321 if (!mtu) 1322 mtu = ip_next_mtu(ip->ip_len, 1323 1); 1324 if (mtu < max(296, V_tcp_minmss 1325 + sizeof(struct tcpiphdr))) 1326 mtu = 0; 1327 if (!mtu) 1328 mtu = V_tcp_mssdflt 1329 + sizeof(struct tcpiphdr); 1330 /* 1331 * Only cache the the MTU if it 1332 * is smaller than the interface 1333 * or route MTU. tcp_mtudisc() 1334 * will do right thing by itself. 1335 */ 1336 if (mtu <= tcp_maxmtu(&inc, NULL)) 1337 tcp_hc_updatemtu(&inc, mtu); 1338 } 1339 1340 inp = (*notify)(inp, inetctlerrmap[cmd]); 1341 } 1342 } 1343 if (inp != NULL) 1344 INP_WUNLOCK(inp); 1345 } else { 1346 inc.inc_fport = th->th_dport; 1347 inc.inc_lport = th->th_sport; 1348 inc.inc_faddr = faddr; 1349 inc.inc_laddr = ip->ip_src; 1350 #ifdef INET6 1351 inc.inc_isipv6 = 0; 1352 #endif 1353 syncache_unreach(&inc, th); 1354 } 1355 INP_INFO_WUNLOCK(&V_tcbinfo); 1356 } else 1357 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify); 1358 } 1359 1360 #ifdef INET6 1361 void 1362 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1363 { 1364 INIT_VNET_INET(curvnet); 1365 struct tcphdr th; 1366 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify; 1367 struct ip6_hdr *ip6; 1368 struct mbuf *m; 1369 struct ip6ctlparam *ip6cp = NULL; 1370 const struct sockaddr_in6 *sa6_src = NULL; 1371 int off; 1372 struct tcp_portonly { 1373 u_int16_t th_sport; 1374 u_int16_t th_dport; 1375 } *thp; 1376 1377 if (sa->sa_family != AF_INET6 || 1378 sa->sa_len != sizeof(struct sockaddr_in6)) 1379 return; 1380 1381 if (cmd == PRC_MSGSIZE) 1382 notify = tcp_mtudisc; 1383 else if (!PRC_IS_REDIRECT(cmd) && 1384 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) 1385 return; 1386 /* Source quench is depreciated. */ 1387 else if (cmd == PRC_QUENCH) 1388 return; 1389 1390 /* if the parameter is from icmp6, decode it. */ 1391 if (d != NULL) { 1392 ip6cp = (struct ip6ctlparam *)d; 1393 m = ip6cp->ip6c_m; 1394 ip6 = ip6cp->ip6c_ip6; 1395 off = ip6cp->ip6c_off; 1396 sa6_src = ip6cp->ip6c_src; 1397 } else { 1398 m = NULL; 1399 ip6 = NULL; 1400 off = 0; /* fool gcc */ 1401 sa6_src = &sa6_any; 1402 } 1403 1404 if (ip6 != NULL) { 1405 struct in_conninfo inc; 1406 /* 1407 * XXX: We assume that when IPV6 is non NULL, 1408 * M and OFF are valid. 1409 */ 1410 1411 /* check if we can safely examine src and dst ports */ 1412 if (m->m_pkthdr.len < off + sizeof(*thp)) 1413 return; 1414 1415 bzero(&th, sizeof(th)); 1416 m_copydata(m, off, sizeof(*thp), (caddr_t)&th); 1417 1418 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport, 1419 (struct sockaddr *)ip6cp->ip6c_src, 1420 th.th_sport, cmd, NULL, notify); 1421 1422 inc.inc_fport = th.th_dport; 1423 inc.inc_lport = th.th_sport; 1424 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1425 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1426 inc.inc_isipv6 = 1; 1427 INP_INFO_WLOCK(&V_tcbinfo); 1428 syncache_unreach(&inc, &th); 1429 INP_INFO_WUNLOCK(&V_tcbinfo); 1430 } else 1431 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src, 1432 0, cmd, NULL, notify); 1433 } 1434 #endif /* INET6 */ 1435 1436 1437 /* 1438 * Following is where TCP initial sequence number generation occurs. 1439 * 1440 * There are two places where we must use initial sequence numbers: 1441 * 1. In SYN-ACK packets. 1442 * 2. In SYN packets. 1443 * 1444 * All ISNs for SYN-ACK packets are generated by the syncache. See 1445 * tcp_syncache.c for details. 1446 * 1447 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1448 * depends on this property. In addition, these ISNs should be 1449 * unguessable so as to prevent connection hijacking. To satisfy 1450 * the requirements of this situation, the algorithm outlined in 1451 * RFC 1948 is used, with only small modifications. 1452 * 1453 * Implementation details: 1454 * 1455 * Time is based off the system timer, and is corrected so that it 1456 * increases by one megabyte per second. This allows for proper 1457 * recycling on high speed LANs while still leaving over an hour 1458 * before rollover. 1459 * 1460 * As reading the *exact* system time is too expensive to be done 1461 * whenever setting up a TCP connection, we increment the time 1462 * offset in two ways. First, a small random positive increment 1463 * is added to isn_offset for each connection that is set up. 1464 * Second, the function tcp_isn_tick fires once per clock tick 1465 * and increments isn_offset as necessary so that sequence numbers 1466 * are incremented at approximately ISN_BYTES_PER_SECOND. The 1467 * random positive increments serve only to ensure that the same 1468 * exact sequence number is never sent out twice (as could otherwise 1469 * happen when a port is recycled in less than the system tick 1470 * interval.) 1471 * 1472 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1473 * between seeding of isn_secret. This is normally set to zero, 1474 * as reseeding should not be necessary. 1475 * 1476 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset, 1477 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In 1478 * general, this means holding an exclusive (write) lock. 1479 */ 1480 1481 #define ISN_BYTES_PER_SECOND 1048576 1482 #define ISN_STATIC_INCREMENT 4096 1483 #define ISN_RANDOM_INCREMENT (4096 - 1) 1484 1485 #ifdef VIMAGE_GLOBALS 1486 static u_char isn_secret[32]; 1487 static int isn_last_reseed; 1488 static u_int32_t isn_offset, isn_offset_old; 1489 #endif 1490 1491 tcp_seq 1492 tcp_new_isn(struct tcpcb *tp) 1493 { 1494 INIT_VNET_INET(tp->t_vnet); 1495 MD5_CTX isn_ctx; 1496 u_int32_t md5_buffer[4]; 1497 tcp_seq new_isn; 1498 1499 INP_WLOCK_ASSERT(tp->t_inpcb); 1500 1501 ISN_LOCK(); 1502 /* Seed if this is the first use, reseed if requested. */ 1503 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) && 1504 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz) 1505 < (u_int)ticks))) { 1506 read_random(&V_isn_secret, sizeof(V_isn_secret)); 1507 V_isn_last_reseed = ticks; 1508 } 1509 1510 /* Compute the md5 hash and return the ISN. */ 1511 MD5Init(&isn_ctx); 1512 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short)); 1513 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short)); 1514 #ifdef INET6 1515 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) { 1516 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1517 sizeof(struct in6_addr)); 1518 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1519 sizeof(struct in6_addr)); 1520 } else 1521 #endif 1522 { 1523 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1524 sizeof(struct in_addr)); 1525 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1526 sizeof(struct in_addr)); 1527 } 1528 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret)); 1529 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1530 new_isn = (tcp_seq) md5_buffer[0]; 1531 V_isn_offset += ISN_STATIC_INCREMENT + 1532 (arc4random() & ISN_RANDOM_INCREMENT); 1533 new_isn += V_isn_offset; 1534 ISN_UNLOCK(); 1535 return (new_isn); 1536 } 1537 1538 /* 1539 * Increment the offset to the next ISN_BYTES_PER_SECOND / 100 boundary 1540 * to keep time flowing at a relatively constant rate. If the random 1541 * increments have already pushed us past the projected offset, do nothing. 1542 */ 1543 static void 1544 tcp_isn_tick(void *xtp) 1545 { 1546 VNET_ITERATOR_DECL(vnet_iter); 1547 u_int32_t projected_offset; 1548 1549 ISN_LOCK(); 1550 VNET_LIST_RLOCK(); 1551 VNET_FOREACH(vnet_iter) { 1552 CURVNET_SET(vnet_iter); /* XXX appease INVARIANTS */ 1553 INIT_VNET_INET(curvnet); 1554 projected_offset = 1555 V_isn_offset_old + ISN_BYTES_PER_SECOND / 100; 1556 1557 if (SEQ_GT(projected_offset, V_isn_offset)) 1558 V_isn_offset = projected_offset; 1559 1560 V_isn_offset_old = V_isn_offset; 1561 CURVNET_RESTORE(); 1562 } 1563 VNET_LIST_RUNLOCK(); 1564 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL); 1565 ISN_UNLOCK(); 1566 } 1567 1568 /* 1569 * When a specific ICMP unreachable message is received and the 1570 * connection state is SYN-SENT, drop the connection. This behavior 1571 * is controlled by the icmp_may_rst sysctl. 1572 */ 1573 struct inpcb * 1574 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1575 { 1576 #ifdef INVARIANTS 1577 INIT_VNET_INET(inp->inp_vnet); 1578 #endif 1579 struct tcpcb *tp; 1580 1581 INP_INFO_WLOCK_ASSERT(&V_tcbinfo); 1582 INP_WLOCK_ASSERT(inp); 1583 1584 if ((inp->inp_vflag & INP_TIMEWAIT) || 1585 (inp->inp_vflag & INP_DROPPED)) 1586 return (inp); 1587 1588 tp = intotcpcb(inp); 1589 if (tp->t_state != TCPS_SYN_SENT) 1590 return (inp); 1591 1592 tp = tcp_drop(tp, errno); 1593 if (tp != NULL) 1594 return (inp); 1595 else 1596 return (NULL); 1597 } 1598 1599 /* 1600 * When `need fragmentation' ICMP is received, update our idea of the MSS 1601 * based on the new value in the route. Also nudge TCP to send something, 1602 * since we know the packet we just sent was dropped. 1603 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1604 */ 1605 struct inpcb * 1606 tcp_mtudisc(struct inpcb *inp, int errno) 1607 { 1608 INIT_VNET_INET(inp->inp_vnet); 1609 struct tcpcb *tp; 1610 struct socket *so; 1611 1612 INP_WLOCK_ASSERT(inp); 1613 if ((inp->inp_vflag & INP_TIMEWAIT) || 1614 (inp->inp_vflag & INP_DROPPED)) 1615 return (inp); 1616 1617 tp = intotcpcb(inp); 1618 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL")); 1619 1620 tcp_mss_update(tp, -1, NULL, NULL); 1621 1622 so = inp->inp_socket; 1623 SOCKBUF_LOCK(&so->so_snd); 1624 /* If the mss is larger than the socket buffer, decrease the mss. */ 1625 if (so->so_snd.sb_hiwat < tp->t_maxseg) 1626 tp->t_maxseg = so->so_snd.sb_hiwat; 1627 SOCKBUF_UNLOCK(&so->so_snd); 1628 1629 V_tcpstat.tcps_mturesent++; 1630 tp->t_rtttime = 0; 1631 tp->snd_nxt = tp->snd_una; 1632 tcp_free_sackholes(tp); 1633 tp->snd_recover = tp->snd_max; 1634 if (tp->t_flags & TF_SACK_PERMIT) 1635 EXIT_FASTRECOVERY(tp); 1636 tcp_output_send(tp); 1637 return (inp); 1638 } 1639 1640 /* 1641 * Look-up the routing entry to the peer of this inpcb. If no route 1642 * is found and it cannot be allocated, then return 0. This routine 1643 * is called by TCP routines that access the rmx structure and by 1644 * tcp_mss_update to get the peer/interface MTU. 1645 */ 1646 u_long 1647 tcp_maxmtu(struct in_conninfo *inc, int *flags) 1648 { 1649 struct route sro; 1650 struct sockaddr_in *dst; 1651 struct ifnet *ifp; 1652 u_long maxmtu = 0; 1653 1654 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer")); 1655 1656 bzero(&sro, sizeof(sro)); 1657 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1658 dst = (struct sockaddr_in *)&sro.ro_dst; 1659 dst->sin_family = AF_INET; 1660 dst->sin_len = sizeof(*dst); 1661 dst->sin_addr = inc->inc_faddr; 1662 in_rtalloc_ign(&sro, RTF_CLONING, inc->inc_fibnum); 1663 } 1664 if (sro.ro_rt != NULL) { 1665 ifp = sro.ro_rt->rt_ifp; 1666 if (sro.ro_rt->rt_rmx.rmx_mtu == 0) 1667 maxmtu = ifp->if_mtu; 1668 else 1669 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 1670 1671 /* Report additional interface capabilities. */ 1672 if (flags != NULL) { 1673 if (ifp->if_capenable & IFCAP_TSO4 && 1674 ifp->if_hwassist & CSUM_TSO) 1675 *flags |= CSUM_TSO; 1676 } 1677 RTFREE(sro.ro_rt); 1678 } 1679 return (maxmtu); 1680 } 1681 1682 #ifdef INET6 1683 u_long 1684 tcp_maxmtu6(struct in_conninfo *inc, int *flags) 1685 { 1686 struct route_in6 sro6; 1687 struct ifnet *ifp; 1688 u_long maxmtu = 0; 1689 1690 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer")); 1691 1692 bzero(&sro6, sizeof(sro6)); 1693 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1694 sro6.ro_dst.sin6_family = AF_INET6; 1695 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1696 sro6.ro_dst.sin6_addr = inc->inc6_faddr; 1697 rtalloc_ign((struct route *)&sro6, RTF_CLONING); 1698 } 1699 if (sro6.ro_rt != NULL) { 1700 ifp = sro6.ro_rt->rt_ifp; 1701 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0) 1702 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp); 1703 else 1704 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu, 1705 IN6_LINKMTU(sro6.ro_rt->rt_ifp)); 1706 1707 /* Report additional interface capabilities. */ 1708 if (flags != NULL) { 1709 if (ifp->if_capenable & IFCAP_TSO6 && 1710 ifp->if_hwassist & CSUM_TSO) 1711 *flags |= CSUM_TSO; 1712 } 1713 RTFREE(sro6.ro_rt); 1714 } 1715 1716 return (maxmtu); 1717 } 1718 #endif /* INET6 */ 1719 1720 #ifdef IPSEC 1721 /* compute ESP/AH header size for TCP, including outer IP header. */ 1722 size_t 1723 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1724 { 1725 struct inpcb *inp; 1726 struct mbuf *m; 1727 size_t hdrsiz; 1728 struct ip *ip; 1729 #ifdef INET6 1730 struct ip6_hdr *ip6; 1731 #endif 1732 struct tcphdr *th; 1733 1734 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1735 return (0); 1736 MGETHDR(m, M_DONTWAIT, MT_DATA); 1737 if (!m) 1738 return (0); 1739 1740 #ifdef INET6 1741 if ((inp->inp_vflag & INP_IPV6) != 0) { 1742 ip6 = mtod(m, struct ip6_hdr *); 1743 th = (struct tcphdr *)(ip6 + 1); 1744 m->m_pkthdr.len = m->m_len = 1745 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1746 tcpip_fillheaders(inp, ip6, th); 1747 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1748 } else 1749 #endif /* INET6 */ 1750 { 1751 ip = mtod(m, struct ip *); 1752 th = (struct tcphdr *)(ip + 1); 1753 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1754 tcpip_fillheaders(inp, ip, th); 1755 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1756 } 1757 1758 m_free(m); 1759 return (hdrsiz); 1760 } 1761 #endif /* IPSEC */ 1762 1763 /* 1764 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1765 * 1766 * This code attempts to calculate the bandwidth-delay product as a 1767 * means of determining the optimal window size to maximize bandwidth, 1768 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1769 * routers. This code also does a fairly good job keeping RTTs in check 1770 * across slow links like modems. We implement an algorithm which is very 1771 * similar (but not meant to be) TCP/Vegas. The code operates on the 1772 * transmitter side of a TCP connection and so only effects the transmit 1773 * side of the connection. 1774 * 1775 * BACKGROUND: TCP makes no provision for the management of buffer space 1776 * at the end points or at the intermediate routers and switches. A TCP 1777 * stream, whether using NewReno or not, will eventually buffer as 1778 * many packets as it is able and the only reason this typically works is 1779 * due to the fairly small default buffers made available for a connection 1780 * (typicaly 16K or 32K). As machines use larger windows and/or window 1781 * scaling it is now fairly easy for even a single TCP connection to blow-out 1782 * all available buffer space not only on the local interface, but on 1783 * intermediate routers and switches as well. NewReno makes a misguided 1784 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1785 * then backing off, then steadily increasing the window again until another 1786 * failure occurs, ad-infinitum. This results in terrible oscillation that 1787 * is only made worse as network loads increase and the idea of intentionally 1788 * blowing out network buffers is, frankly, a terrible way to manage network 1789 * resources. 1790 * 1791 * It is far better to limit the transmit window prior to the failure 1792 * condition being achieved. There are two general ways to do this: First 1793 * you can 'scan' through different transmit window sizes and locate the 1794 * point where the RTT stops increasing, indicating that you have filled the 1795 * pipe, then scan backwards until you note that RTT stops decreasing, then 1796 * repeat ad-infinitum. This method works in principle but has severe 1797 * implementation issues due to RTT variances, timer granularity, and 1798 * instability in the algorithm which can lead to many false positives and 1799 * create oscillations as well as interact badly with other TCP streams 1800 * implementing the same algorithm. 1801 * 1802 * The second method is to limit the window to the bandwidth delay product 1803 * of the link. This is the method we implement. RTT variances and our 1804 * own manipulation of the congestion window, bwnd, can potentially 1805 * destabilize the algorithm. For this reason we have to stabilize the 1806 * elements used to calculate the window. We do this by using the minimum 1807 * observed RTT, the long term average of the observed bandwidth, and 1808 * by adding two segments worth of slop. It isn't perfect but it is able 1809 * to react to changing conditions and gives us a very stable basis on 1810 * which to extend the algorithm. 1811 */ 1812 void 1813 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1814 { 1815 INIT_VNET_INET(tp->t_vnet); 1816 u_long bw; 1817 u_long bwnd; 1818 int save_ticks; 1819 1820 INP_WLOCK_ASSERT(tp->t_inpcb); 1821 1822 /* 1823 * If inflight_enable is disabled in the middle of a tcp connection, 1824 * make sure snd_bwnd is effectively disabled. 1825 */ 1826 if (V_tcp_inflight_enable == 0 || 1827 tp->t_rttlow < V_tcp_inflight_rttthresh) { 1828 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1829 tp->snd_bandwidth = 0; 1830 return; 1831 } 1832 1833 /* 1834 * Figure out the bandwidth. Due to the tick granularity this 1835 * is a very rough number and it MUST be averaged over a fairly 1836 * long period of time. XXX we need to take into account a link 1837 * that is not using all available bandwidth, but for now our 1838 * slop will ramp us up if this case occurs and the bandwidth later 1839 * increases. 1840 * 1841 * Note: if ticks rollover 'bw' may wind up negative. We must 1842 * effectively reset t_bw_rtttime for this case. 1843 */ 1844 save_ticks = ticks; 1845 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1) 1846 return; 1847 1848 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 1849 (save_ticks - tp->t_bw_rtttime); 1850 tp->t_bw_rtttime = save_ticks; 1851 tp->t_bw_rtseq = ack_seq; 1852 if (tp->t_bw_rtttime == 0 || (int)bw < 0) 1853 return; 1854 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1855 1856 tp->snd_bandwidth = bw; 1857 1858 /* 1859 * Calculate the semi-static bandwidth delay product, plus two maximal 1860 * segments. The additional slop puts us squarely in the sweet 1861 * spot and also handles the bandwidth run-up case and stabilization. 1862 * Without the slop we could be locking ourselves into a lower 1863 * bandwidth. 1864 * 1865 * Situations Handled: 1866 * (1) Prevents over-queueing of packets on LANs, especially on 1867 * high speed LANs, allowing larger TCP buffers to be 1868 * specified, and also does a good job preventing 1869 * over-queueing of packets over choke points like modems 1870 * (at least for the transmit side). 1871 * 1872 * (2) Is able to handle changing network loads (bandwidth 1873 * drops so bwnd drops, bandwidth increases so bwnd 1874 * increases). 1875 * 1876 * (3) Theoretically should stabilize in the face of multiple 1877 * connections implementing the same algorithm (this may need 1878 * a little work). 1879 * 1880 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1881 * be adjusted with a sysctl but typically only needs to be 1882 * on very slow connections. A value no smaller then 5 1883 * should be used, but only reduce this default if you have 1884 * no other choice. 1885 */ 1886 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1887 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + V_tcp_inflight_stab * tp->t_maxseg / 10; 1888 #undef USERTT 1889 1890 if (tcp_inflight_debug > 0) { 1891 static int ltime; 1892 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1893 ltime = ticks; 1894 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1895 tp, 1896 bw, 1897 tp->t_rttbest, 1898 tp->t_srtt, 1899 bwnd 1900 ); 1901 } 1902 } 1903 if ((long)bwnd < V_tcp_inflight_min) 1904 bwnd = V_tcp_inflight_min; 1905 if (bwnd > V_tcp_inflight_max) 1906 bwnd = V_tcp_inflight_max; 1907 if ((long)bwnd < tp->t_maxseg * 2) 1908 bwnd = tp->t_maxseg * 2; 1909 tp->snd_bwnd = bwnd; 1910 } 1911 1912 #ifdef TCP_SIGNATURE 1913 /* 1914 * Callback function invoked by m_apply() to digest TCP segment data 1915 * contained within an mbuf chain. 1916 */ 1917 static int 1918 tcp_signature_apply(void *fstate, void *data, u_int len) 1919 { 1920 1921 MD5Update(fstate, (u_char *)data, len); 1922 return (0); 1923 } 1924 1925 /* 1926 * Compute TCP-MD5 hash of a TCP segment. (RFC2385) 1927 * 1928 * Parameters: 1929 * m pointer to head of mbuf chain 1930 * _unused 1931 * len length of TCP segment data, excluding options 1932 * optlen length of TCP segment options 1933 * buf pointer to storage for computed MD5 digest 1934 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND) 1935 * 1936 * We do this over ip, tcphdr, segment data, and the key in the SADB. 1937 * When called from tcp_input(), we can be sure that th_sum has been 1938 * zeroed out and verified already. 1939 * 1940 * Return 0 if successful, otherwise return -1. 1941 * 1942 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 1943 * search with the destination IP address, and a 'magic SPI' to be 1944 * determined by the application. This is hardcoded elsewhere to 1179 1945 * right now. Another branch of this code exists which uses the SPD to 1946 * specify per-application flows but it is unstable. 1947 */ 1948 int 1949 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen, 1950 u_char *buf, u_int direction) 1951 { 1952 INIT_VNET_IPSEC(curvnet); 1953 union sockaddr_union dst; 1954 struct ippseudo ippseudo; 1955 MD5_CTX ctx; 1956 int doff; 1957 struct ip *ip; 1958 struct ipovly *ipovly; 1959 struct secasvar *sav; 1960 struct tcphdr *th; 1961 #ifdef INET6 1962 struct ip6_hdr *ip6; 1963 struct in6_addr in6; 1964 char ip6buf[INET6_ADDRSTRLEN]; 1965 uint32_t plen; 1966 uint16_t nhdr; 1967 #endif 1968 u_short savecsum; 1969 1970 KASSERT(m != NULL, ("NULL mbuf chain")); 1971 KASSERT(buf != NULL, ("NULL signature pointer")); 1972 1973 /* Extract the destination from the IP header in the mbuf. */ 1974 bzero(&dst, sizeof(union sockaddr_union)); 1975 ip = mtod(m, struct ip *); 1976 #ifdef INET6 1977 ip6 = NULL; /* Make the compiler happy. */ 1978 #endif 1979 switch (ip->ip_v) { 1980 case IPVERSION: 1981 dst.sa.sa_len = sizeof(struct sockaddr_in); 1982 dst.sa.sa_family = AF_INET; 1983 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ? 1984 ip->ip_src : ip->ip_dst; 1985 break; 1986 #ifdef INET6 1987 case (IPV6_VERSION >> 4): 1988 ip6 = mtod(m, struct ip6_hdr *); 1989 dst.sa.sa_len = sizeof(struct sockaddr_in6); 1990 dst.sa.sa_family = AF_INET6; 1991 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ? 1992 ip6->ip6_src : ip6->ip6_dst; 1993 break; 1994 #endif 1995 default: 1996 return (EINVAL); 1997 /* NOTREACHED */ 1998 break; 1999 } 2000 2001 /* Look up an SADB entry which matches the address of the peer. */ 2002 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2003 if (sav == NULL) { 2004 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__, 2005 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) : 2006 #ifdef INET6 2007 (ip->ip_v == (IPV6_VERSION >> 4)) ? 2008 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) : 2009 #endif 2010 "(unsupported)")); 2011 return (EINVAL); 2012 } 2013 2014 MD5Init(&ctx); 2015 /* 2016 * Step 1: Update MD5 hash with IP(v6) pseudo-header. 2017 * 2018 * XXX The ippseudo header MUST be digested in network byte order, 2019 * or else we'll fail the regression test. Assume all fields we've 2020 * been doing arithmetic on have been in host byte order. 2021 * XXX One cannot depend on ipovly->ih_len here. When called from 2022 * tcp_output(), the underlying ip_len member has not yet been set. 2023 */ 2024 switch (ip->ip_v) { 2025 case IPVERSION: 2026 ipovly = (struct ipovly *)ip; 2027 ippseudo.ippseudo_src = ipovly->ih_src; 2028 ippseudo.ippseudo_dst = ipovly->ih_dst; 2029 ippseudo.ippseudo_pad = 0; 2030 ippseudo.ippseudo_p = IPPROTO_TCP; 2031 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + 2032 optlen); 2033 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2034 2035 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip)); 2036 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen; 2037 break; 2038 #ifdef INET6 2039 /* 2040 * RFC 2385, 2.0 Proposal 2041 * For IPv6, the pseudo-header is as described in RFC 2460, namely the 2042 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero- 2043 * extended next header value (to form 32 bits), and 32-bit segment 2044 * length. 2045 * Note: Upper-Layer Packet Length comes before Next Header. 2046 */ 2047 case (IPV6_VERSION >> 4): 2048 in6 = ip6->ip6_src; 2049 in6_clearscope(&in6); 2050 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2051 in6 = ip6->ip6_dst; 2052 in6_clearscope(&in6); 2053 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2054 plen = htonl(len + sizeof(struct tcphdr) + optlen); 2055 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t)); 2056 nhdr = 0; 2057 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2058 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2059 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2060 nhdr = IPPROTO_TCP; 2061 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2062 2063 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr)); 2064 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen; 2065 break; 2066 #endif 2067 default: 2068 return (EINVAL); 2069 /* NOTREACHED */ 2070 break; 2071 } 2072 2073 2074 /* 2075 * Step 2: Update MD5 hash with TCP header, excluding options. 2076 * The TCP checksum must be set to zero. 2077 */ 2078 savecsum = th->th_sum; 2079 th->th_sum = 0; 2080 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2081 th->th_sum = savecsum; 2082 2083 /* 2084 * Step 3: Update MD5 hash with TCP segment data. 2085 * Use m_apply() to avoid an early m_pullup(). 2086 */ 2087 if (len > 0) 2088 m_apply(m, doff, len, tcp_signature_apply, &ctx); 2089 2090 /* 2091 * Step 4: Update MD5 hash with shared secret. 2092 */ 2093 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 2094 MD5Final(buf, &ctx); 2095 2096 key_sa_recordxfer(sav, m); 2097 KEY_FREESAV(&sav); 2098 return (0); 2099 } 2100 #endif /* TCP_SIGNATURE */ 2101 2102 static int 2103 sysctl_drop(SYSCTL_HANDLER_ARGS) 2104 { 2105 INIT_VNET_INET(curvnet); 2106 #ifdef INET6 2107 INIT_VNET_INET6(curvnet); 2108 #endif 2109 /* addrs[0] is a foreign socket, addrs[1] is a local one. */ 2110 struct sockaddr_storage addrs[2]; 2111 struct inpcb *inp; 2112 struct tcpcb *tp; 2113 struct tcptw *tw; 2114 struct sockaddr_in *fin, *lin; 2115 #ifdef INET6 2116 struct sockaddr_in6 *fin6, *lin6; 2117 struct in6_addr f6, l6; 2118 #endif 2119 int error; 2120 2121 inp = NULL; 2122 fin = lin = NULL; 2123 #ifdef INET6 2124 fin6 = lin6 = NULL; 2125 #endif 2126 error = 0; 2127 2128 if (req->oldptr != NULL || req->oldlen != 0) 2129 return (EINVAL); 2130 if (req->newptr == NULL) 2131 return (EPERM); 2132 if (req->newlen < sizeof(addrs)) 2133 return (ENOMEM); 2134 error = SYSCTL_IN(req, &addrs, sizeof(addrs)); 2135 if (error) 2136 return (error); 2137 2138 switch (addrs[0].ss_family) { 2139 #ifdef INET6 2140 case AF_INET6: 2141 fin6 = (struct sockaddr_in6 *)&addrs[0]; 2142 lin6 = (struct sockaddr_in6 *)&addrs[1]; 2143 if (fin6->sin6_len != sizeof(struct sockaddr_in6) || 2144 lin6->sin6_len != sizeof(struct sockaddr_in6)) 2145 return (EINVAL); 2146 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) { 2147 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr)) 2148 return (EINVAL); 2149 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]); 2150 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]); 2151 fin = (struct sockaddr_in *)&addrs[0]; 2152 lin = (struct sockaddr_in *)&addrs[1]; 2153 break; 2154 } 2155 error = sa6_embedscope(fin6, V_ip6_use_defzone); 2156 if (error) 2157 return (error); 2158 error = sa6_embedscope(lin6, V_ip6_use_defzone); 2159 if (error) 2160 return (error); 2161 break; 2162 #endif 2163 case AF_INET: 2164 fin = (struct sockaddr_in *)&addrs[0]; 2165 lin = (struct sockaddr_in *)&addrs[1]; 2166 if (fin->sin_len != sizeof(struct sockaddr_in) || 2167 lin->sin_len != sizeof(struct sockaddr_in)) 2168 return (EINVAL); 2169 break; 2170 default: 2171 return (EINVAL); 2172 } 2173 INP_INFO_WLOCK(&V_tcbinfo); 2174 switch (addrs[0].ss_family) { 2175 #ifdef INET6 2176 case AF_INET6: 2177 inp = in6_pcblookup_hash(&V_tcbinfo, &f6, fin6->sin6_port, 2178 &l6, lin6->sin6_port, 0, NULL); 2179 break; 2180 #endif 2181 case AF_INET: 2182 inp = in_pcblookup_hash(&V_tcbinfo, fin->sin_addr, 2183 fin->sin_port, lin->sin_addr, lin->sin_port, 0, NULL); 2184 break; 2185 } 2186 if (inp != NULL) { 2187 INP_WLOCK(inp); 2188 if (inp->inp_vflag & INP_TIMEWAIT) { 2189 /* 2190 * XXXRW: There currently exists a state where an 2191 * inpcb is present, but its timewait state has been 2192 * discarded. For now, don't allow dropping of this 2193 * type of inpcb. 2194 */ 2195 tw = intotw(inp); 2196 if (tw != NULL) 2197 tcp_twclose(tw, 0); 2198 else 2199 INP_WUNLOCK(inp); 2200 } else if (!(inp->inp_vflag & INP_DROPPED) && 2201 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) { 2202 tp = intotcpcb(inp); 2203 tp = tcp_drop(tp, ECONNABORTED); 2204 if (tp != NULL) 2205 INP_WUNLOCK(inp); 2206 } else 2207 INP_WUNLOCK(inp); 2208 } else 2209 error = ESRCH; 2210 INP_INFO_WUNLOCK(&V_tcbinfo); 2211 return (error); 2212 } 2213 2214 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop, 2215 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL, 2216 0, sysctl_drop, "", "Drop TCP connection"); 2217 2218 /* 2219 * Generate a standardized TCP log line for use throughout the 2220 * tcp subsystem. Memory allocation is done with M_NOWAIT to 2221 * allow use in the interrupt context. 2222 * 2223 * NB: The caller MUST free(s, M_TCPLOG) the returned string. 2224 * NB: The function may return NULL if memory allocation failed. 2225 * 2226 * Due to header inclusion and ordering limitations the struct ip 2227 * and ip6_hdr pointers have to be passed as void pointers. 2228 */ 2229 char * 2230 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr, 2231 const void *ip6hdr) 2232 { 2233 char *s, *sp; 2234 size_t size; 2235 struct ip *ip; 2236 #ifdef INET6 2237 const struct ip6_hdr *ip6; 2238 2239 ip6 = (const struct ip6_hdr *)ip6hdr; 2240 #endif /* INET6 */ 2241 ip = (struct ip *)ip4hdr; 2242 2243 /* 2244 * The log line looks like this: 2245 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>" 2246 */ 2247 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") + 2248 sizeof(PRINT_TH_FLAGS) + 1 + 2249 #ifdef INET6 2250 2 * INET6_ADDRSTRLEN; 2251 #else 2252 2 * INET_ADDRSTRLEN; 2253 #endif /* INET6 */ 2254 2255 /* Is logging enabled? */ 2256 if (tcp_log_debug == 0 && tcp_log_in_vain == 0) 2257 return (NULL); 2258 2259 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT); 2260 if (s == NULL) 2261 return (NULL); 2262 2263 strcat(s, "TCP: ["); 2264 sp = s + strlen(s); 2265 2266 if (inc && inc->inc_isipv6 == 0) { 2267 inet_ntoa_r(inc->inc_faddr, sp); 2268 sp = s + strlen(s); 2269 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2270 sp = s + strlen(s); 2271 inet_ntoa_r(inc->inc_laddr, sp); 2272 sp = s + strlen(s); 2273 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2274 #ifdef INET6 2275 } else if (inc) { 2276 ip6_sprintf(sp, &inc->inc6_faddr); 2277 sp = s + strlen(s); 2278 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport)); 2279 sp = s + strlen(s); 2280 ip6_sprintf(sp, &inc->inc6_laddr); 2281 sp = s + strlen(s); 2282 sprintf(sp, "]:%i", ntohs(inc->inc_lport)); 2283 } else if (ip6 && th) { 2284 ip6_sprintf(sp, &ip6->ip6_src); 2285 sp = s + strlen(s); 2286 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2287 sp = s + strlen(s); 2288 ip6_sprintf(sp, &ip6->ip6_dst); 2289 sp = s + strlen(s); 2290 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2291 #endif /* INET6 */ 2292 } else if (ip && th) { 2293 inet_ntoa_r(ip->ip_src, sp); 2294 sp = s + strlen(s); 2295 sprintf(sp, "]:%i to [", ntohs(th->th_sport)); 2296 sp = s + strlen(s); 2297 inet_ntoa_r(ip->ip_dst, sp); 2298 sp = s + strlen(s); 2299 sprintf(sp, "]:%i", ntohs(th->th_dport)); 2300 } else { 2301 free(s, M_TCPLOG); 2302 return (NULL); 2303 } 2304 sp = s + strlen(s); 2305 if (th) 2306 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS); 2307 if (*(s + size - 1) != '\0') 2308 panic("%s: string too long", __func__); 2309 return (s); 2310 } 2311