1 /* 2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved. 3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved. 4 * 5 * This code is derived from software contributed to The DragonFly Project 6 * by Jeffrey M. Hsu. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of The DragonFly Project nor the names of its 17 * contributors may be used to endorse or promote products derived 18 * from this software without specific, prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 36 * The Regents of the University of California. All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. All advertising materials mentioning features or use of this software 47 * must display the following acknowledgement: 48 * This product includes software developed by the University of 49 * California, Berkeley and its contributors. 50 * 4. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 67 * $FreeBSD: src/sys/netinet/tcp_subr.c,v 1.73.2.31 2003/01/24 05:11:34 sam Exp $ 68 */ 69 70 #include "opt_compat.h" 71 #include "opt_inet.h" 72 #include "opt_inet6.h" 73 #include "opt_ipsec.h" 74 #include "opt_tcpdebug.h" 75 76 #include <sys/param.h> 77 #include <sys/systm.h> 78 #include <sys/callout.h> 79 #include <sys/kernel.h> 80 #include <sys/sysctl.h> 81 #include <sys/malloc.h> 82 #include <sys/mpipe.h> 83 #include <sys/mbuf.h> 84 #ifdef INET6 85 #include <sys/domain.h> 86 #endif 87 #include <sys/proc.h> 88 #include <sys/priv.h> 89 #include <sys/socket.h> 90 #include <sys/socketops.h> 91 #include <sys/socketvar.h> 92 #include <sys/protosw.h> 93 #include <sys/random.h> 94 #include <sys/in_cksum.h> 95 #include <sys/ktr.h> 96 97 #include <net/route.h> 98 #include <net/if.h> 99 #include <net/netisr.h> 100 101 #define _IP_VHL 102 #include <netinet/in.h> 103 #include <netinet/in_systm.h> 104 #include <netinet/ip.h> 105 #include <netinet/ip6.h> 106 #include <netinet/in_pcb.h> 107 #include <netinet6/in6_pcb.h> 108 #include <netinet/in_var.h> 109 #include <netinet/ip_var.h> 110 #include <netinet6/ip6_var.h> 111 #include <netinet/ip_icmp.h> 112 #ifdef INET6 113 #include <netinet/icmp6.h> 114 #endif 115 #include <netinet/tcp.h> 116 #include <netinet/tcp_fsm.h> 117 #include <netinet/tcp_seq.h> 118 #include <netinet/tcp_timer.h> 119 #include <netinet/tcp_timer2.h> 120 #include <netinet/tcp_var.h> 121 #include <netinet6/tcp6_var.h> 122 #include <netinet/tcpip.h> 123 #ifdef TCPDEBUG 124 #include <netinet/tcp_debug.h> 125 #endif 126 #include <netinet6/ip6protosw.h> 127 128 #ifdef IPSEC 129 #include <netinet6/ipsec.h> 130 #include <netproto/key/key.h> 131 #ifdef INET6 132 #include <netinet6/ipsec6.h> 133 #endif 134 #endif 135 136 #ifdef FAST_IPSEC 137 #include <netproto/ipsec/ipsec.h> 138 #ifdef INET6 139 #include <netproto/ipsec/ipsec6.h> 140 #endif 141 #define IPSEC 142 #endif 143 144 #include <sys/md5.h> 145 #include <machine/smp.h> 146 147 #include <sys/msgport2.h> 148 #include <sys/mplock2.h> 149 #include <net/netmsg2.h> 150 151 #if !defined(KTR_TCP) 152 #define KTR_TCP KTR_ALL 153 #endif 154 /* 155 KTR_INFO_MASTER(tcp); 156 KTR_INFO(KTR_TCP, tcp, rxmsg, 0, "tcp getmsg", 0); 157 KTR_INFO(KTR_TCP, tcp, wait, 1, "tcp waitmsg", 0); 158 KTR_INFO(KTR_TCP, tcp, delayed, 2, "tcp execute delayed ops", 0); 159 #define logtcp(name) KTR_LOG(tcp_ ## name) 160 */ 161 162 #define TCP_IW_MAXSEGS_DFLT 4 163 #define TCP_IW_CAPSEGS_DFLT 3 164 165 struct inpcbinfo tcbinfo[MAXCPU]; 166 struct tcpcbackqhead tcpcbackq[MAXCPU]; 167 168 static struct lwkt_token tcp_port_token = 169 LWKT_TOKEN_INITIALIZER(tcp_port_token); 170 171 int tcp_mssdflt = TCP_MSS; 172 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 173 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size"); 174 175 #ifdef INET6 176 int tcp_v6mssdflt = TCP6_MSS; 177 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW, 178 &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6"); 179 #endif 180 181 /* 182 * Minimum MSS we accept and use. This prevents DoS attacks where 183 * we are forced to a ridiculous low MSS like 20 and send hundreds 184 * of packets instead of one. The effect scales with the available 185 * bandwidth and quickly saturates the CPU and network interface 186 * with packet generation and sending. Set to zero to disable MINMSS 187 * checking. This setting prevents us from sending too small packets. 188 */ 189 int tcp_minmss = TCP_MINMSS; 190 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 191 &tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 192 193 #if 0 194 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 195 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 196 &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time"); 197 #endif 198 199 int tcp_do_rfc1323 = 1; 200 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 201 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions"); 202 203 static int tcp_tcbhashsize = 0; 204 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 205 &tcp_tcbhashsize, 0, "Size of TCP control block hashtable"); 206 207 static int do_tcpdrain = 1; 208 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 209 "Enable tcp_drain routine for extra help when low on mbufs"); 210 211 static int icmp_may_rst = 1; 212 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 213 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 214 215 static int tcp_isn_reseed_interval = 0; 216 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 217 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 218 219 /* 220 * TCP bandwidth limiting sysctls. The inflight limiter is now turned on 221 * by default, but with generous values which should allow maximal 222 * bandwidth. In particular, the slop defaults to 50 (5 packets). 223 * 224 * The reason for doing this is that the limiter is the only mechanism we 225 * have which seems to do a really good job preventing receiver RX rings 226 * on network interfaces from getting blown out. Even though GigE/10GigE 227 * is supposed to flow control it looks like either it doesn't actually 228 * do it or Open Source drivers do not properly enable it. 229 * 230 * People using the limiter to reduce bottlenecks on slower WAN connections 231 * should set the slop to 20 (2 packets). 232 */ 233 static int tcp_inflight_enable = 1; 234 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW, 235 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 236 237 static int tcp_inflight_debug = 0; 238 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW, 239 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 240 241 static int tcp_inflight_min = 6144; 242 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW, 243 &tcp_inflight_min, 0, "Lower bound for TCP inflight window"); 244 245 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 246 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW, 247 &tcp_inflight_max, 0, "Upper bound for TCP inflight window"); 248 249 static int tcp_inflight_stab = 50; 250 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW, 251 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 3 packets)"); 252 253 static int tcp_do_rfc3390 = 1; 254 SYSCTL_INT(_net_inet_tcp, OID_AUTO, rfc3390, CTLFLAG_RW, 255 &tcp_do_rfc3390, 0, 256 "Enable RFC 3390 (Increasing TCP's Initial Congestion Window)"); 257 258 static u_long tcp_iw_maxsegs = TCP_IW_MAXSEGS_DFLT; 259 SYSCTL_ULONG(_net_inet_tcp, OID_AUTO, iwmaxsegs, CTLFLAG_RW, 260 &tcp_iw_maxsegs, 0, "TCP IW segments max"); 261 262 static u_long tcp_iw_capsegs = TCP_IW_CAPSEGS_DFLT; 263 SYSCTL_ULONG(_net_inet_tcp, OID_AUTO, iwcapsegs, CTLFLAG_RW, 264 &tcp_iw_capsegs, 0, "TCP IW segments"); 265 266 int tcp_low_rtobase = 1; 267 SYSCTL_INT(_net_inet_tcp, OID_AUTO, low_rtobase, CTLFLAG_RW, 268 &tcp_low_rtobase, 0, "Lowering the Initial RTO (RFC 6298)"); 269 270 static int tcp_do_ncr = 1; 271 SYSCTL_INT(_net_inet_tcp, OID_AUTO, ncr, CTLFLAG_RW, 272 &tcp_do_ncr, 0, "Non-Congestion Robustness (RFC 4653)"); 273 274 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives"); 275 static struct malloc_pipe tcptemp_mpipe; 276 277 static void tcp_willblock(void); 278 static void tcp_notify (struct inpcb *, int); 279 280 struct tcp_stats tcpstats_percpu[MAXCPU] __cachealign; 281 282 static int 283 sysctl_tcpstats(SYSCTL_HANDLER_ARGS) 284 { 285 int cpu, error = 0; 286 287 for (cpu = 0; cpu < ncpus; ++cpu) { 288 if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu], 289 sizeof(struct tcp_stats)))) 290 break; 291 if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu], 292 sizeof(struct tcp_stats)))) 293 break; 294 } 295 296 return (error); 297 } 298 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 299 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics"); 300 301 /* 302 * Target size of TCP PCB hash tables. Must be a power of two. 303 * 304 * Note that this can be overridden by the kernel environment 305 * variable net.inet.tcp.tcbhashsize 306 */ 307 #ifndef TCBHASHSIZE 308 #define TCBHASHSIZE 512 309 #endif 310 311 /* 312 * This is the actual shape of what we allocate using the zone 313 * allocator. Doing it this way allows us to protect both structures 314 * using the same generation count, and also eliminates the overhead 315 * of allocating tcpcbs separately. By hiding the structure here, 316 * we avoid changing most of the rest of the code (although it needs 317 * to be changed, eventually, for greater efficiency). 318 */ 319 #define ALIGNMENT 32 320 #define ALIGNM1 (ALIGNMENT - 1) 321 struct inp_tp { 322 union { 323 struct inpcb inp; 324 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 325 } inp_tp_u; 326 struct tcpcb tcb; 327 struct tcp_callout inp_tp_rexmt; 328 struct tcp_callout inp_tp_persist; 329 struct tcp_callout inp_tp_keep; 330 struct tcp_callout inp_tp_2msl; 331 struct tcp_callout inp_tp_delack; 332 struct netmsg_tcp_timer inp_tp_timermsg; 333 struct netmsg_base inp_tp_sndmore; 334 }; 335 #undef ALIGNMENT 336 #undef ALIGNM1 337 338 /* 339 * Tcp initialization 340 */ 341 void 342 tcp_init(void) 343 { 344 struct inpcbporthead *porthashbase; 345 struct inpcbinfo *ticb; 346 u_long porthashmask; 347 int hashsize = TCBHASHSIZE; 348 int cpu; 349 350 /* 351 * note: tcptemp is used for keepalives, and it is ok for an 352 * allocation to fail so do not specify MPF_INT. 353 */ 354 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp), 355 25, -1, 0, NULL, NULL, NULL); 356 357 tcp_delacktime = TCPTV_DELACK; 358 tcp_keepinit = TCPTV_KEEP_INIT; 359 tcp_keepidle = TCPTV_KEEP_IDLE; 360 tcp_keepintvl = TCPTV_KEEPINTVL; 361 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 362 tcp_msl = TCPTV_MSL; 363 tcp_rexmit_min = TCPTV_MIN; 364 tcp_rexmit_slop = TCPTV_CPU_VAR; 365 366 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 367 if (!powerof2(hashsize)) { 368 kprintf("WARNING: TCB hash size not a power of 2\n"); 369 hashsize = 512; /* safe default */ 370 } 371 tcp_tcbhashsize = hashsize; 372 porthashbase = hashinit(hashsize, M_PCB, &porthashmask); 373 374 for (cpu = 0; cpu < ncpus2; cpu++) { 375 ticb = &tcbinfo[cpu]; 376 in_pcbinfo_init(ticb); 377 ticb->cpu = cpu; 378 ticb->hashbase = hashinit(hashsize, M_PCB, 379 &ticb->hashmask); 380 ticb->porthashbase = porthashbase; 381 ticb->porthashmask = porthashmask; 382 ticb->porttoken = &tcp_port_token; 383 #if 0 384 ticb->porthashbase = hashinit(hashsize, M_PCB, 385 &ticb->porthashmask); 386 #endif 387 ticb->wildcardhashbase = hashinit(hashsize, M_PCB, 388 &ticb->wildcardhashmask); 389 ticb->ipi_size = sizeof(struct inp_tp); 390 TAILQ_INIT(&tcpcbackq[cpu]); 391 } 392 393 tcp_reass_maxseg = nmbclusters / 16; 394 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg); 395 396 #ifdef INET6 397 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 398 #else 399 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 400 #endif 401 if (max_protohdr < TCP_MINPROTOHDR) 402 max_protohdr = TCP_MINPROTOHDR; 403 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 404 panic("tcp_init"); 405 #undef TCP_MINPROTOHDR 406 407 /* 408 * Initialize TCP statistics counters for each CPU. 409 */ 410 for (cpu = 0; cpu < ncpus; ++cpu) { 411 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats)); 412 } 413 414 syncache_init(); 415 netisr_register_rollup(tcp_willblock, NETISR_ROLLUP_PRIO_TCP); 416 } 417 418 static void 419 tcp_willblock(void) 420 { 421 struct tcpcb *tp; 422 int cpu = mycpu->gd_cpuid; 423 424 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) { 425 KKASSERT(tp->t_flags & TF_ONOUTPUTQ); 426 tp->t_flags &= ~TF_ONOUTPUTQ; 427 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq); 428 tcp_output(tp); 429 } 430 } 431 432 /* 433 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 434 * tcp_template used to store this data in mbufs, but we now recopy it out 435 * of the tcpcb each time to conserve mbufs. 436 */ 437 void 438 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr, boolean_t tso) 439 { 440 struct inpcb *inp = tp->t_inpcb; 441 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 442 443 #ifdef INET6 444 if (inp->inp_vflag & INP_IPV6) { 445 struct ip6_hdr *ip6; 446 447 ip6 = (struct ip6_hdr *)ip_ptr; 448 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 449 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 450 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 451 (IPV6_VERSION & IPV6_VERSION_MASK); 452 ip6->ip6_nxt = IPPROTO_TCP; 453 ip6->ip6_plen = sizeof(struct tcphdr); 454 ip6->ip6_src = inp->in6p_laddr; 455 ip6->ip6_dst = inp->in6p_faddr; 456 tcp_hdr->th_sum = 0; 457 } else 458 #endif 459 { 460 struct ip *ip = (struct ip *) ip_ptr; 461 u_int plen; 462 463 ip->ip_vhl = IP_VHL_BORING; 464 ip->ip_tos = 0; 465 ip->ip_len = 0; 466 ip->ip_id = 0; 467 ip->ip_off = 0; 468 ip->ip_ttl = 0; 469 ip->ip_sum = 0; 470 ip->ip_p = IPPROTO_TCP; 471 ip->ip_src = inp->inp_laddr; 472 ip->ip_dst = inp->inp_faddr; 473 474 if (tso) 475 plen = htons(IPPROTO_TCP); 476 else 477 plen = htons(sizeof(struct tcphdr) + IPPROTO_TCP); 478 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, 479 ip->ip_dst.s_addr, plen); 480 } 481 482 tcp_hdr->th_sport = inp->inp_lport; 483 tcp_hdr->th_dport = inp->inp_fport; 484 tcp_hdr->th_seq = 0; 485 tcp_hdr->th_ack = 0; 486 tcp_hdr->th_x2 = 0; 487 tcp_hdr->th_off = 5; 488 tcp_hdr->th_flags = 0; 489 tcp_hdr->th_win = 0; 490 tcp_hdr->th_urp = 0; 491 } 492 493 /* 494 * Create template to be used to send tcp packets on a connection. 495 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 496 * use for this function is in keepalives, which use tcp_respond. 497 */ 498 struct tcptemp * 499 tcp_maketemplate(struct tcpcb *tp) 500 { 501 struct tcptemp *tmp; 502 503 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL) 504 return (NULL); 505 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t, FALSE); 506 return (tmp); 507 } 508 509 void 510 tcp_freetemplate(struct tcptemp *tmp) 511 { 512 mpipe_free(&tcptemp_mpipe, tmp); 513 } 514 515 /* 516 * Send a single message to the TCP at address specified by 517 * the given TCP/IP header. If m == NULL, then we make a copy 518 * of the tcpiphdr at ti and send directly to the addressed host. 519 * This is used to force keep alive messages out using the TCP 520 * template for a connection. If flags are given then we send 521 * a message back to the TCP which originated the * segment ti, 522 * and discard the mbuf containing it and any other attached mbufs. 523 * 524 * In any case the ack and sequence number of the transmitted 525 * segment are as specified by the parameters. 526 * 527 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 528 */ 529 void 530 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 531 tcp_seq ack, tcp_seq seq, int flags) 532 { 533 int tlen; 534 int win = 0; 535 struct route *ro = NULL; 536 struct route sro; 537 struct ip *ip = ipgen; 538 struct tcphdr *nth; 539 int ipflags = 0; 540 struct route_in6 *ro6 = NULL; 541 struct route_in6 sro6; 542 struct ip6_hdr *ip6 = ipgen; 543 boolean_t use_tmpro = TRUE; 544 #ifdef INET6 545 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6); 546 #else 547 const boolean_t isipv6 = FALSE; 548 #endif 549 550 if (tp != NULL) { 551 if (!(flags & TH_RST)) { 552 win = ssb_space(&tp->t_inpcb->inp_socket->so_rcv); 553 if (win < 0) 554 win = 0; 555 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 556 win = (long)TCP_MAXWIN << tp->rcv_scale; 557 } 558 /* 559 * Don't use the route cache of a listen socket, 560 * it is not MPSAFE; use temporary route cache. 561 */ 562 if (tp->t_state != TCPS_LISTEN) { 563 if (isipv6) 564 ro6 = &tp->t_inpcb->in6p_route; 565 else 566 ro = &tp->t_inpcb->inp_route; 567 use_tmpro = FALSE; 568 } 569 } 570 if (use_tmpro) { 571 if (isipv6) { 572 ro6 = &sro6; 573 bzero(ro6, sizeof *ro6); 574 } else { 575 ro = &sro; 576 bzero(ro, sizeof *ro); 577 } 578 } 579 if (m == NULL) { 580 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 581 if (m == NULL) 582 return; 583 tlen = 0; 584 m->m_data += max_linkhdr; 585 if (isipv6) { 586 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr)); 587 ip6 = mtod(m, struct ip6_hdr *); 588 nth = (struct tcphdr *)(ip6 + 1); 589 } else { 590 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); 591 ip = mtod(m, struct ip *); 592 nth = (struct tcphdr *)(ip + 1); 593 } 594 bcopy(th, nth, sizeof(struct tcphdr)); 595 flags = TH_ACK; 596 } else { 597 m_freem(m->m_next); 598 m->m_next = NULL; 599 m->m_data = (caddr_t)ipgen; 600 /* m_len is set later */ 601 tlen = 0; 602 #define xchg(a, b, type) { type t; t = a; a = b; b = t; } 603 if (isipv6) { 604 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 605 nth = (struct tcphdr *)(ip6 + 1); 606 } else { 607 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 608 nth = (struct tcphdr *)(ip + 1); 609 } 610 if (th != nth) { 611 /* 612 * this is usually a case when an extension header 613 * exists between the IPv6 header and the 614 * TCP header. 615 */ 616 nth->th_sport = th->th_sport; 617 nth->th_dport = th->th_dport; 618 } 619 xchg(nth->th_dport, nth->th_sport, n_short); 620 #undef xchg 621 } 622 if (isipv6) { 623 ip6->ip6_flow = 0; 624 ip6->ip6_vfc = IPV6_VERSION; 625 ip6->ip6_nxt = IPPROTO_TCP; 626 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen)); 627 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 628 } else { 629 tlen += sizeof(struct tcpiphdr); 630 ip->ip_len = tlen; 631 ip->ip_ttl = ip_defttl; 632 } 633 m->m_len = tlen; 634 m->m_pkthdr.len = tlen; 635 m->m_pkthdr.rcvif = NULL; 636 nth->th_seq = htonl(seq); 637 nth->th_ack = htonl(ack); 638 nth->th_x2 = 0; 639 nth->th_off = sizeof(struct tcphdr) >> 2; 640 nth->th_flags = flags; 641 if (tp != NULL) 642 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 643 else 644 nth->th_win = htons((u_short)win); 645 nth->th_urp = 0; 646 if (isipv6) { 647 nth->th_sum = 0; 648 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 649 sizeof(struct ip6_hdr), 650 tlen - sizeof(struct ip6_hdr)); 651 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 652 (ro6 && ro6->ro_rt) ? 653 ro6->ro_rt->rt_ifp : NULL); 654 } else { 655 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 656 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 657 m->m_pkthdr.csum_flags = CSUM_TCP; 658 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 659 m->m_pkthdr.csum_thlen = sizeof(struct tcphdr); 660 } 661 #ifdef TCPDEBUG 662 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 663 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 664 #endif 665 if (isipv6) { 666 ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 667 tp ? tp->t_inpcb : NULL); 668 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) { 669 RTFREE(ro6->ro_rt); 670 ro6->ro_rt = NULL; 671 } 672 } else { 673 ipflags |= IP_DEBUGROUTE; 674 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 675 if ((ro == &sro) && (ro->ro_rt != NULL)) { 676 RTFREE(ro->ro_rt); 677 ro->ro_rt = NULL; 678 } 679 } 680 } 681 682 /* 683 * Create a new TCP control block, making an 684 * empty reassembly queue and hooking it to the argument 685 * protocol control block. The `inp' parameter must have 686 * come from the zone allocator set up in tcp_init(). 687 */ 688 struct tcpcb * 689 tcp_newtcpcb(struct inpcb *inp) 690 { 691 struct inp_tp *it; 692 struct tcpcb *tp; 693 #ifdef INET6 694 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 695 #else 696 const boolean_t isipv6 = FALSE; 697 #endif 698 699 it = (struct inp_tp *)inp; 700 tp = &it->tcb; 701 bzero(tp, sizeof(struct tcpcb)); 702 TAILQ_INIT(&tp->t_segq); 703 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt; 704 tp->t_rxtthresh = tcprexmtthresh; 705 706 /* Set up our timeouts. */ 707 tp->tt_rexmt = &it->inp_tp_rexmt; 708 tp->tt_persist = &it->inp_tp_persist; 709 tp->tt_keep = &it->inp_tp_keep; 710 tp->tt_2msl = &it->inp_tp_2msl; 711 tp->tt_delack = &it->inp_tp_delack; 712 tcp_inittimers(tp); 713 714 /* 715 * Zero out timer message. We don't create it here, 716 * since the current CPU may not be the owner of this 717 * inpcb. 718 */ 719 tp->tt_msg = &it->inp_tp_timermsg; 720 bzero(tp->tt_msg, sizeof(*tp->tt_msg)); 721 722 tp->t_keepinit = tcp_keepinit; 723 tp->t_keepidle = tcp_keepidle; 724 tp->t_keepintvl = tcp_keepintvl; 725 tp->t_keepcnt = tcp_keepcnt; 726 tp->t_maxidle = tp->t_keepintvl * tp->t_keepcnt; 727 728 if (tcp_do_ncr) 729 tp->t_flags |= TF_NCR; 730 if (tcp_do_rfc1323) 731 tp->t_flags |= (TF_REQ_SCALE | TF_REQ_TSTMP); 732 733 tp->t_inpcb = inp; /* XXX */ 734 tp->t_state = TCPS_CLOSED; 735 /* 736 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 737 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 738 * reasonable initial retransmit time. 739 */ 740 tp->t_srtt = TCPTV_SRTTBASE; 741 tp->t_rttvar = 742 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 743 tp->t_rttmin = tcp_rexmit_min; 744 tp->t_rxtcur = TCPTV_RTOBASE; 745 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 746 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 747 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 748 tp->snd_last = ticks; 749 tp->t_rcvtime = ticks; 750 /* 751 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 752 * because the socket may be bound to an IPv6 wildcard address, 753 * which may match an IPv4-mapped IPv6 address. 754 */ 755 inp->inp_ip_ttl = ip_defttl; 756 inp->inp_ppcb = tp; 757 tcp_sack_tcpcb_init(tp); 758 759 tp->tt_sndmore = &it->inp_tp_sndmore; 760 tcp_output_init(tp); 761 762 return (tp); /* XXX */ 763 } 764 765 /* 766 * Drop a TCP connection, reporting the specified error. 767 * If connection is synchronized, then send a RST to peer. 768 */ 769 struct tcpcb * 770 tcp_drop(struct tcpcb *tp, int error) 771 { 772 struct socket *so = tp->t_inpcb->inp_socket; 773 774 if (TCPS_HAVERCVDSYN(tp->t_state)) { 775 tp->t_state = TCPS_CLOSED; 776 tcp_output(tp); 777 tcpstat.tcps_drops++; 778 } else 779 tcpstat.tcps_conndrops++; 780 if (error == ETIMEDOUT && tp->t_softerror) 781 error = tp->t_softerror; 782 so->so_error = error; 783 return (tcp_close(tp)); 784 } 785 786 struct netmsg_listen_detach { 787 struct netmsg_base base; 788 struct tcpcb *nm_tp; 789 }; 790 791 static void 792 tcp_listen_detach_handler(netmsg_t msg) 793 { 794 struct netmsg_listen_detach *nmsg = (struct netmsg_listen_detach *)msg; 795 struct tcpcb *tp = nmsg->nm_tp; 796 int cpu = mycpuid, nextcpu; 797 798 if (tp->t_flags & TF_LISTEN) 799 syncache_destroy(tp); 800 801 in_pcbremwildcardhash_oncpu(tp->t_inpcb, &tcbinfo[cpu]); 802 803 nextcpu = cpu + 1; 804 if (nextcpu < ncpus2) 805 lwkt_forwardmsg(netisr_portfn(nextcpu), &nmsg->base.lmsg); 806 else 807 lwkt_replymsg(&nmsg->base.lmsg, 0); 808 } 809 810 /* 811 * Close a TCP control block: 812 * discard all space held by the tcp 813 * discard internet protocol block 814 * wake up any sleepers 815 */ 816 struct tcpcb * 817 tcp_close(struct tcpcb *tp) 818 { 819 struct tseg_qent *q; 820 struct inpcb *inp = tp->t_inpcb; 821 struct socket *so = inp->inp_socket; 822 struct rtentry *rt; 823 boolean_t dosavessthresh; 824 #ifdef INET6 825 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 826 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0); 827 #else 828 const boolean_t isipv6 = FALSE; 829 #endif 830 831 /* 832 * INP_WILDCARD_MP indicates that listen(2) has been called on 833 * this socket. This implies: 834 * - A wildcard inp's hash is replicated for each protocol thread. 835 * - Syncache for this inp grows independently in each protocol 836 * thread. 837 * - There is more than one cpu 838 * 839 * We have to chain a message to the rest of the protocol threads 840 * to cleanup the wildcard hash and the syncache. The cleanup 841 * in the current protocol thread is defered till the end of this 842 * function. 843 * 844 * NOTE: 845 * After cleanup the inp's hash and syncache entries, this inp will 846 * no longer be available to the rest of the protocol threads, so we 847 * are safe to whack the inp in the following code. 848 */ 849 if (inp->inp_flags & INP_WILDCARD_MP) { 850 struct netmsg_listen_detach nmsg; 851 852 KKASSERT(so->so_port == netisr_portfn(0)); 853 KKASSERT(&curthread->td_msgport == netisr_portfn(0)); 854 KKASSERT(inp->inp_pcbinfo == &tcbinfo[0]); 855 856 netmsg_init(&nmsg.base, NULL, &curthread->td_msgport, 857 MSGF_PRIORITY, tcp_listen_detach_handler); 858 nmsg.nm_tp = tp; 859 lwkt_domsg(netisr_portfn(1), &nmsg.base.lmsg, 0); 860 861 inp->inp_flags &= ~INP_WILDCARD_MP; 862 } 863 864 KKASSERT(tp->t_state != TCPS_TERMINATING); 865 tp->t_state = TCPS_TERMINATING; 866 867 /* 868 * Make sure that all of our timers are stopped before we 869 * delete the PCB. For listen TCP socket (tp->tt_msg == NULL), 870 * timers are never used. If timer message is never created 871 * (tp->tt_msg->tt_tcb == NULL), timers are never used too. 872 */ 873 if (tp->tt_msg != NULL && tp->tt_msg->tt_tcb != NULL) { 874 tcp_callout_stop(tp, tp->tt_rexmt); 875 tcp_callout_stop(tp, tp->tt_persist); 876 tcp_callout_stop(tp, tp->tt_keep); 877 tcp_callout_stop(tp, tp->tt_2msl); 878 tcp_callout_stop(tp, tp->tt_delack); 879 } 880 881 if (tp->t_flags & TF_ONOUTPUTQ) { 882 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid); 883 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq); 884 tp->t_flags &= ~TF_ONOUTPUTQ; 885 } 886 887 /* 888 * If we got enough samples through the srtt filter, 889 * save the rtt and rttvar in the routing entry. 890 * 'Enough' is arbitrarily defined as the 16 samples. 891 * 16 samples is enough for the srtt filter to converge 892 * to within 5% of the correct value; fewer samples and 893 * we could save a very bogus rtt. 894 * 895 * Don't update the default route's characteristics and don't 896 * update anything that the user "locked". 897 */ 898 if (tp->t_rttupdated >= 16) { 899 u_long i = 0; 900 901 if (isipv6) { 902 struct sockaddr_in6 *sin6; 903 904 if ((rt = inp->in6p_route.ro_rt) == NULL) 905 goto no_valid_rt; 906 sin6 = (struct sockaddr_in6 *)rt_key(rt); 907 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 908 goto no_valid_rt; 909 } else 910 if ((rt = inp->inp_route.ro_rt) == NULL || 911 ((struct sockaddr_in *)rt_key(rt))-> 912 sin_addr.s_addr == INADDR_ANY) 913 goto no_valid_rt; 914 915 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) { 916 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 917 if (rt->rt_rmx.rmx_rtt && i) 918 /* 919 * filter this update to half the old & half 920 * the new values, converting scale. 921 * See route.h and tcp_var.h for a 922 * description of the scaling constants. 923 */ 924 rt->rt_rmx.rmx_rtt = 925 (rt->rt_rmx.rmx_rtt + i) / 2; 926 else 927 rt->rt_rmx.rmx_rtt = i; 928 tcpstat.tcps_cachedrtt++; 929 } 930 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) { 931 i = tp->t_rttvar * 932 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 933 if (rt->rt_rmx.rmx_rttvar && i) 934 rt->rt_rmx.rmx_rttvar = 935 (rt->rt_rmx.rmx_rttvar + i) / 2; 936 else 937 rt->rt_rmx.rmx_rttvar = i; 938 tcpstat.tcps_cachedrttvar++; 939 } 940 /* 941 * The old comment here said: 942 * update the pipelimit (ssthresh) if it has been updated 943 * already or if a pipesize was specified & the threshhold 944 * got below half the pipesize. I.e., wait for bad news 945 * before we start updating, then update on both good 946 * and bad news. 947 * 948 * But we want to save the ssthresh even if no pipesize is 949 * specified explicitly in the route, because such 950 * connections still have an implicit pipesize specified 951 * by the global tcp_sendspace. In the absence of a reliable 952 * way to calculate the pipesize, it will have to do. 953 */ 954 i = tp->snd_ssthresh; 955 if (rt->rt_rmx.rmx_sendpipe != 0) 956 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2); 957 else 958 dosavessthresh = (i < so->so_snd.ssb_hiwat/2); 959 if (dosavessthresh || 960 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) && 961 (rt->rt_rmx.rmx_ssthresh != 0))) { 962 /* 963 * convert the limit from user data bytes to 964 * packets then to packet data bytes. 965 */ 966 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 967 if (i < 2) 968 i = 2; 969 i *= tp->t_maxseg + 970 (isipv6 ? 971 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 972 sizeof(struct tcpiphdr)); 973 if (rt->rt_rmx.rmx_ssthresh) 974 rt->rt_rmx.rmx_ssthresh = 975 (rt->rt_rmx.rmx_ssthresh + i) / 2; 976 else 977 rt->rt_rmx.rmx_ssthresh = i; 978 tcpstat.tcps_cachedssthresh++; 979 } 980 } 981 982 no_valid_rt: 983 /* free the reassembly queue, if any */ 984 while((q = TAILQ_FIRST(&tp->t_segq)) != NULL) { 985 TAILQ_REMOVE(&tp->t_segq, q, tqe_q); 986 m_freem(q->tqe_m); 987 kfree(q, M_TSEGQ); 988 atomic_add_int(&tcp_reass_qsize, -1); 989 } 990 /* throw away SACK blocks in scoreboard*/ 991 if (TCP_DO_SACK(tp)) 992 tcp_sack_destroy(&tp->scb); 993 994 inp->inp_ppcb = NULL; 995 soisdisconnected(so); 996 /* note: pcb detached later on */ 997 998 tcp_destroy_timermsg(tp); 999 tcp_output_cancel(tp); 1000 1001 if (tp->t_flags & TF_LISTEN) 1002 syncache_destroy(tp); 1003 1004 so_async_rcvd_drop(so); 1005 /* Drop the reference for the asynchronized pru_rcvd */ 1006 sofree(so); 1007 1008 /* 1009 * NOTE: 1010 * pcbdetach removes any wildcard hash entry on the current CPU. 1011 */ 1012 #ifdef INET6 1013 if (isafinet6) 1014 in6_pcbdetach(inp); 1015 else 1016 #endif 1017 in_pcbdetach(inp); 1018 1019 tcpstat.tcps_closed++; 1020 return (NULL); 1021 } 1022 1023 static __inline void 1024 tcp_drain_oncpu(struct inpcbhead *head) 1025 { 1026 struct inpcb *marker; 1027 struct inpcb *inpb; 1028 struct tcpcb *tcpb; 1029 struct tseg_qent *te; 1030 1031 /* 1032 * Allows us to block while running the list 1033 */ 1034 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1035 marker->inp_flags |= INP_PLACEMARKER; 1036 LIST_INSERT_HEAD(head, marker, inp_list); 1037 1038 while ((inpb = LIST_NEXT(marker, inp_list)) != NULL) { 1039 if ((inpb->inp_flags & INP_PLACEMARKER) == 0 && 1040 (tcpb = intotcpcb(inpb)) != NULL && 1041 (te = TAILQ_FIRST(&tcpb->t_segq)) != NULL) { 1042 TAILQ_REMOVE(&tcpb->t_segq, te, tqe_q); 1043 if (te->tqe_th->th_flags & TH_FIN) 1044 tcpb->t_flags &= ~TF_QUEDFIN; 1045 m_freem(te->tqe_m); 1046 kfree(te, M_TSEGQ); 1047 atomic_add_int(&tcp_reass_qsize, -1); 1048 /* retry */ 1049 } else { 1050 LIST_REMOVE(marker, inp_list); 1051 LIST_INSERT_AFTER(inpb, marker, inp_list); 1052 } 1053 } 1054 LIST_REMOVE(marker, inp_list); 1055 kfree(marker, M_TEMP); 1056 } 1057 1058 struct netmsg_tcp_drain { 1059 struct netmsg_base base; 1060 struct inpcbhead *nm_head; 1061 }; 1062 1063 static void 1064 tcp_drain_handler(netmsg_t msg) 1065 { 1066 struct netmsg_tcp_drain *nm = (void *)msg; 1067 1068 tcp_drain_oncpu(nm->nm_head); 1069 lwkt_replymsg(&nm->base.lmsg, 0); 1070 } 1071 1072 void 1073 tcp_drain(void) 1074 { 1075 int cpu; 1076 1077 if (!do_tcpdrain) 1078 return; 1079 1080 /* 1081 * Walk the tcpbs, if existing, and flush the reassembly queue, 1082 * if there is one... 1083 * XXX: The "Net/3" implementation doesn't imply that the TCP 1084 * reassembly queue should be flushed, but in a situation 1085 * where we're really low on mbufs, this is potentially 1086 * useful. 1087 */ 1088 for (cpu = 0; cpu < ncpus2; cpu++) { 1089 struct netmsg_tcp_drain *nm; 1090 1091 if (cpu == mycpu->gd_cpuid) { 1092 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead); 1093 } else { 1094 nm = kmalloc(sizeof(struct netmsg_tcp_drain), 1095 M_LWKTMSG, M_NOWAIT); 1096 if (nm == NULL) 1097 continue; 1098 netmsg_init(&nm->base, NULL, &netisr_afree_rport, 1099 0, tcp_drain_handler); 1100 nm->nm_head = &tcbinfo[cpu].pcblisthead; 1101 lwkt_sendmsg(netisr_portfn(cpu), &nm->base.lmsg); 1102 } 1103 } 1104 } 1105 1106 /* 1107 * Notify a tcp user of an asynchronous error; 1108 * store error as soft error, but wake up user 1109 * (for now, won't do anything until can select for soft error). 1110 * 1111 * Do not wake up user since there currently is no mechanism for 1112 * reporting soft errors (yet - a kqueue filter may be added). 1113 */ 1114 static void 1115 tcp_notify(struct inpcb *inp, int error) 1116 { 1117 struct tcpcb *tp = intotcpcb(inp); 1118 1119 /* 1120 * Ignore some errors if we are hooked up. 1121 * If connection hasn't completed, has retransmitted several times, 1122 * and receives a second error, give up now. This is better 1123 * than waiting a long time to establish a connection that 1124 * can never complete. 1125 */ 1126 if (tp->t_state == TCPS_ESTABLISHED && 1127 (error == EHOSTUNREACH || error == ENETUNREACH || 1128 error == EHOSTDOWN)) { 1129 return; 1130 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1131 tp->t_softerror) 1132 tcp_drop(tp, error); 1133 else 1134 tp->t_softerror = error; 1135 #if 0 1136 wakeup(&so->so_timeo); 1137 sorwakeup(so); 1138 sowwakeup(so); 1139 #endif 1140 } 1141 1142 static int 1143 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1144 { 1145 int error, i, n; 1146 struct inpcb *marker; 1147 struct inpcb *inp; 1148 globaldata_t gd; 1149 int origcpu, ccpu; 1150 1151 error = 0; 1152 n = 0; 1153 1154 /* 1155 * The process of preparing the TCB list is too time-consuming and 1156 * resource-intensive to repeat twice on every request. 1157 */ 1158 if (req->oldptr == NULL) { 1159 for (ccpu = 0; ccpu < ncpus; ++ccpu) { 1160 gd = globaldata_find(ccpu); 1161 n += tcbinfo[gd->gd_cpuid].ipi_count; 1162 } 1163 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb); 1164 return (0); 1165 } 1166 1167 if (req->newptr != NULL) 1168 return (EPERM); 1169 1170 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1171 marker->inp_flags |= INP_PLACEMARKER; 1172 1173 /* 1174 * OK, now we're committed to doing something. Run the inpcb list 1175 * for each cpu in the system and construct the output. Use a 1176 * list placemarker to deal with list changes occuring during 1177 * copyout blockages (but otherwise depend on being on the correct 1178 * cpu to avoid races). 1179 */ 1180 origcpu = mycpu->gd_cpuid; 1181 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) { 1182 globaldata_t rgd; 1183 caddr_t inp_ppcb; 1184 struct xtcpcb xt; 1185 int cpu_id; 1186 1187 cpu_id = (origcpu + ccpu) % ncpus; 1188 if ((smp_active_mask & CPUMASK(cpu_id)) == 0) 1189 continue; 1190 rgd = globaldata_find(cpu_id); 1191 lwkt_setcpu_self(rgd); 1192 1193 n = tcbinfo[cpu_id].ipi_count; 1194 1195 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list); 1196 i = 0; 1197 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) { 1198 /* 1199 * process a snapshot of pcbs, ignoring placemarkers 1200 * and using our own to allow SYSCTL_OUT to block. 1201 */ 1202 LIST_REMOVE(marker, inp_list); 1203 LIST_INSERT_AFTER(inp, marker, inp_list); 1204 1205 if (inp->inp_flags & INP_PLACEMARKER) 1206 continue; 1207 if (prison_xinpcb(req->td, inp)) 1208 continue; 1209 1210 xt.xt_len = sizeof xt; 1211 bcopy(inp, &xt.xt_inp, sizeof *inp); 1212 inp_ppcb = inp->inp_ppcb; 1213 if (inp_ppcb != NULL) 1214 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1215 else 1216 bzero(&xt.xt_tp, sizeof xt.xt_tp); 1217 if (inp->inp_socket) 1218 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1219 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0) 1220 break; 1221 ++i; 1222 } 1223 LIST_REMOVE(marker, inp_list); 1224 if (error == 0 && i < n) { 1225 bzero(&xt, sizeof xt); 1226 xt.xt_len = sizeof xt; 1227 while (i < n) { 1228 error = SYSCTL_OUT(req, &xt, sizeof xt); 1229 if (error) 1230 break; 1231 ++i; 1232 } 1233 } 1234 } 1235 1236 /* 1237 * Make sure we are on the same cpu we were on originally, since 1238 * higher level callers expect this. Also don't pollute caches with 1239 * migrated userland data by (eventually) returning to userland 1240 * on a different cpu. 1241 */ 1242 lwkt_setcpu_self(globaldata_find(origcpu)); 1243 kfree(marker, M_TEMP); 1244 return (error); 1245 } 1246 1247 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1248 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1249 1250 static int 1251 tcp_getcred(SYSCTL_HANDLER_ARGS) 1252 { 1253 struct sockaddr_in addrs[2]; 1254 struct inpcb *inp; 1255 int cpu; 1256 int error; 1257 1258 error = priv_check(req->td, PRIV_ROOT); 1259 if (error != 0) 1260 return (error); 1261 error = SYSCTL_IN(req, addrs, sizeof addrs); 1262 if (error != 0) 1263 return (error); 1264 crit_enter(); 1265 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1266 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1267 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1268 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1269 if (inp == NULL || inp->inp_socket == NULL) { 1270 error = ENOENT; 1271 goto out; 1272 } 1273 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1274 out: 1275 crit_exit(); 1276 return (error); 1277 } 1278 1279 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1280 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1281 1282 #ifdef INET6 1283 static int 1284 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1285 { 1286 struct sockaddr_in6 addrs[2]; 1287 struct inpcb *inp; 1288 int error; 1289 boolean_t mapped = FALSE; 1290 1291 error = priv_check(req->td, PRIV_ROOT); 1292 if (error != 0) 1293 return (error); 1294 error = SYSCTL_IN(req, addrs, sizeof addrs); 1295 if (error != 0) 1296 return (error); 1297 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1298 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1299 mapped = TRUE; 1300 else 1301 return (EINVAL); 1302 } 1303 crit_enter(); 1304 if (mapped) { 1305 inp = in_pcblookup_hash(&tcbinfo[0], 1306 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1307 addrs[1].sin6_port, 1308 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1309 addrs[0].sin6_port, 1310 0, NULL); 1311 } else { 1312 inp = in6_pcblookup_hash(&tcbinfo[0], 1313 &addrs[1].sin6_addr, addrs[1].sin6_port, 1314 &addrs[0].sin6_addr, addrs[0].sin6_port, 1315 0, NULL); 1316 } 1317 if (inp == NULL || inp->inp_socket == NULL) { 1318 error = ENOENT; 1319 goto out; 1320 } 1321 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1322 out: 1323 crit_exit(); 1324 return (error); 1325 } 1326 1327 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1328 0, 0, 1329 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1330 #endif 1331 1332 struct netmsg_tcp_notify { 1333 struct netmsg_base base; 1334 void (*nm_notify)(struct inpcb *, int); 1335 struct in_addr nm_faddr; 1336 int nm_arg; 1337 }; 1338 1339 static void 1340 tcp_notifyall_oncpu(netmsg_t msg) 1341 { 1342 struct netmsg_tcp_notify *nm = (struct netmsg_tcp_notify *)msg; 1343 int nextcpu; 1344 1345 in_pcbnotifyall(&tcbinfo[mycpuid].pcblisthead, nm->nm_faddr, 1346 nm->nm_arg, nm->nm_notify); 1347 1348 nextcpu = mycpuid + 1; 1349 if (nextcpu < ncpus2) 1350 lwkt_forwardmsg(netisr_portfn(nextcpu), &nm->base.lmsg); 1351 else 1352 lwkt_replymsg(&nm->base.lmsg, 0); 1353 } 1354 1355 void 1356 tcp_ctlinput(netmsg_t msg) 1357 { 1358 int cmd = msg->ctlinput.nm_cmd; 1359 struct sockaddr *sa = msg->ctlinput.nm_arg; 1360 struct ip *ip = msg->ctlinput.nm_extra; 1361 struct tcphdr *th; 1362 struct in_addr faddr; 1363 struct inpcb *inp; 1364 struct tcpcb *tp; 1365 void (*notify)(struct inpcb *, int) = tcp_notify; 1366 tcp_seq icmpseq; 1367 int arg, cpu; 1368 1369 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) { 1370 goto done; 1371 } 1372 1373 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1374 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1375 goto done; 1376 1377 arg = inetctlerrmap[cmd]; 1378 if (cmd == PRC_QUENCH) { 1379 notify = tcp_quench; 1380 } else if (icmp_may_rst && 1381 (cmd == PRC_UNREACH_ADMIN_PROHIB || 1382 cmd == PRC_UNREACH_PORT || 1383 cmd == PRC_TIMXCEED_INTRANS) && 1384 ip != NULL) { 1385 notify = tcp_drop_syn_sent; 1386 } else if (cmd == PRC_MSGSIZE) { 1387 struct icmp *icmp = (struct icmp *) 1388 ((caddr_t)ip - offsetof(struct icmp, icmp_ip)); 1389 1390 arg = ntohs(icmp->icmp_nextmtu); 1391 notify = tcp_mtudisc; 1392 } else if (PRC_IS_REDIRECT(cmd)) { 1393 ip = NULL; 1394 notify = in_rtchange; 1395 } else if (cmd == PRC_HOSTDEAD) { 1396 ip = NULL; 1397 } 1398 1399 if (ip != NULL) { 1400 crit_enter(); 1401 th = (struct tcphdr *)((caddr_t)ip + 1402 (IP_VHL_HL(ip->ip_vhl) << 2)); 1403 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1404 ip->ip_src.s_addr, th->th_sport); 1405 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1406 ip->ip_src, th->th_sport, 0, NULL); 1407 if ((inp != NULL) && (inp->inp_socket != NULL)) { 1408 icmpseq = htonl(th->th_seq); 1409 tp = intotcpcb(inp); 1410 if (SEQ_GEQ(icmpseq, tp->snd_una) && 1411 SEQ_LT(icmpseq, tp->snd_max)) 1412 (*notify)(inp, arg); 1413 } else { 1414 struct in_conninfo inc; 1415 1416 inc.inc_fport = th->th_dport; 1417 inc.inc_lport = th->th_sport; 1418 inc.inc_faddr = faddr; 1419 inc.inc_laddr = ip->ip_src; 1420 #ifdef INET6 1421 inc.inc_isipv6 = 0; 1422 #endif 1423 syncache_unreach(&inc, th); 1424 } 1425 crit_exit(); 1426 } else { 1427 struct netmsg_tcp_notify *nm; 1428 1429 KKASSERT(&curthread->td_msgport == netisr_portfn(0)); 1430 nm = kmalloc(sizeof(*nm), M_LWKTMSG, M_INTWAIT); 1431 netmsg_init(&nm->base, NULL, &netisr_afree_rport, 1432 0, tcp_notifyall_oncpu); 1433 nm->nm_faddr = faddr; 1434 nm->nm_arg = arg; 1435 nm->nm_notify = notify; 1436 1437 lwkt_sendmsg(netisr_portfn(0), &nm->base.lmsg); 1438 } 1439 done: 1440 lwkt_replymsg(&msg->lmsg, 0); 1441 } 1442 1443 #ifdef INET6 1444 1445 void 1446 tcp6_ctlinput(netmsg_t msg) 1447 { 1448 int cmd = msg->ctlinput.nm_cmd; 1449 struct sockaddr *sa = msg->ctlinput.nm_arg; 1450 void *d = msg->ctlinput.nm_extra; 1451 struct tcphdr th; 1452 void (*notify) (struct inpcb *, int) = tcp_notify; 1453 struct ip6_hdr *ip6; 1454 struct mbuf *m; 1455 struct ip6ctlparam *ip6cp = NULL; 1456 const struct sockaddr_in6 *sa6_src = NULL; 1457 int off; 1458 struct tcp_portonly { 1459 u_int16_t th_sport; 1460 u_int16_t th_dport; 1461 } *thp; 1462 int arg; 1463 1464 if (sa->sa_family != AF_INET6 || 1465 sa->sa_len != sizeof(struct sockaddr_in6)) { 1466 goto out; 1467 } 1468 1469 arg = 0; 1470 if (cmd == PRC_QUENCH) 1471 notify = tcp_quench; 1472 else if (cmd == PRC_MSGSIZE) { 1473 struct ip6ctlparam *ip6cp = d; 1474 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6; 1475 1476 arg = ntohl(icmp6->icmp6_mtu); 1477 notify = tcp_mtudisc; 1478 } else if (!PRC_IS_REDIRECT(cmd) && 1479 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) { 1480 goto out; 1481 } 1482 1483 /* if the parameter is from icmp6, decode it. */ 1484 if (d != NULL) { 1485 ip6cp = (struct ip6ctlparam *)d; 1486 m = ip6cp->ip6c_m; 1487 ip6 = ip6cp->ip6c_ip6; 1488 off = ip6cp->ip6c_off; 1489 sa6_src = ip6cp->ip6c_src; 1490 } else { 1491 m = NULL; 1492 ip6 = NULL; 1493 off = 0; /* fool gcc */ 1494 sa6_src = &sa6_any; 1495 } 1496 1497 if (ip6 != NULL) { 1498 struct in_conninfo inc; 1499 /* 1500 * XXX: We assume that when IPV6 is non NULL, 1501 * M and OFF are valid. 1502 */ 1503 1504 /* check if we can safely examine src and dst ports */ 1505 if (m->m_pkthdr.len < off + sizeof *thp) 1506 goto out; 1507 1508 bzero(&th, sizeof th); 1509 m_copydata(m, off, sizeof *thp, (caddr_t)&th); 1510 1511 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport, 1512 (struct sockaddr *)ip6cp->ip6c_src, 1513 th.th_sport, cmd, arg, notify); 1514 1515 inc.inc_fport = th.th_dport; 1516 inc.inc_lport = th.th_sport; 1517 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1518 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1519 inc.inc_isipv6 = 1; 1520 syncache_unreach(&inc, &th); 1521 } else { 1522 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0, 1523 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify); 1524 } 1525 out: 1526 lwkt_replymsg(&msg->ctlinput.base.lmsg, 0); 1527 } 1528 1529 #endif 1530 1531 /* 1532 * Following is where TCP initial sequence number generation occurs. 1533 * 1534 * There are two places where we must use initial sequence numbers: 1535 * 1. In SYN-ACK packets. 1536 * 2. In SYN packets. 1537 * 1538 * All ISNs for SYN-ACK packets are generated by the syncache. See 1539 * tcp_syncache.c for details. 1540 * 1541 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1542 * depends on this property. In addition, these ISNs should be 1543 * unguessable so as to prevent connection hijacking. To satisfy 1544 * the requirements of this situation, the algorithm outlined in 1545 * RFC 1948 is used to generate sequence numbers. 1546 * 1547 * Implementation details: 1548 * 1549 * Time is based off the system timer, and is corrected so that it 1550 * increases by one megabyte per second. This allows for proper 1551 * recycling on high speed LANs while still leaving over an hour 1552 * before rollover. 1553 * 1554 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1555 * between seeding of isn_secret. This is normally set to zero, 1556 * as reseeding should not be necessary. 1557 * 1558 */ 1559 1560 #define ISN_BYTES_PER_SECOND 1048576 1561 1562 u_char isn_secret[32]; 1563 int isn_last_reseed; 1564 MD5_CTX isn_ctx; 1565 1566 tcp_seq 1567 tcp_new_isn(struct tcpcb *tp) 1568 { 1569 u_int32_t md5_buffer[4]; 1570 tcp_seq new_isn; 1571 1572 /* Seed if this is the first use, reseed if requested. */ 1573 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1574 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1575 < (u_int)ticks))) { 1576 read_random_unlimited(&isn_secret, sizeof isn_secret); 1577 isn_last_reseed = ticks; 1578 } 1579 1580 /* Compute the md5 hash and return the ISN. */ 1581 MD5Init(&isn_ctx); 1582 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 1583 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 1584 #ifdef INET6 1585 if (tp->t_inpcb->inp_vflag & INP_IPV6) { 1586 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1587 sizeof(struct in6_addr)); 1588 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1589 sizeof(struct in6_addr)); 1590 } else 1591 #endif 1592 { 1593 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1594 sizeof(struct in_addr)); 1595 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1596 sizeof(struct in_addr)); 1597 } 1598 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1599 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1600 new_isn = (tcp_seq) md5_buffer[0]; 1601 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1602 return (new_isn); 1603 } 1604 1605 /* 1606 * When a source quench is received, close congestion window 1607 * to one segment. We will gradually open it again as we proceed. 1608 */ 1609 void 1610 tcp_quench(struct inpcb *inp, int error) 1611 { 1612 struct tcpcb *tp = intotcpcb(inp); 1613 1614 if (tp != NULL) { 1615 tp->snd_cwnd = tp->t_maxseg; 1616 tp->snd_wacked = 0; 1617 } 1618 } 1619 1620 /* 1621 * When a specific ICMP unreachable message is received and the 1622 * connection state is SYN-SENT, drop the connection. This behavior 1623 * is controlled by the icmp_may_rst sysctl. 1624 */ 1625 void 1626 tcp_drop_syn_sent(struct inpcb *inp, int error) 1627 { 1628 struct tcpcb *tp = intotcpcb(inp); 1629 1630 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT)) 1631 tcp_drop(tp, error); 1632 } 1633 1634 /* 1635 * When a `need fragmentation' ICMP is received, update our idea of the MSS 1636 * based on the new value in the route. Also nudge TCP to send something, 1637 * since we know the packet we just sent was dropped. 1638 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1639 */ 1640 void 1641 tcp_mtudisc(struct inpcb *inp, int mtu) 1642 { 1643 struct tcpcb *tp = intotcpcb(inp); 1644 struct rtentry *rt; 1645 struct socket *so = inp->inp_socket; 1646 int maxopd, mss; 1647 #ifdef INET6 1648 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0); 1649 #else 1650 const boolean_t isipv6 = FALSE; 1651 #endif 1652 1653 if (tp == NULL) 1654 return; 1655 1656 /* 1657 * If no MTU is provided in the ICMP message, use the 1658 * next lower likely value, as specified in RFC 1191. 1659 */ 1660 if (mtu == 0) { 1661 int oldmtu; 1662 1663 oldmtu = tp->t_maxopd + 1664 (isipv6 ? 1665 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1666 sizeof(struct tcpiphdr)); 1667 mtu = ip_next_mtu(oldmtu, 0); 1668 } 1669 1670 if (isipv6) 1671 rt = tcp_rtlookup6(&inp->inp_inc); 1672 else 1673 rt = tcp_rtlookup(&inp->inp_inc); 1674 if (rt != NULL) { 1675 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu) 1676 mtu = rt->rt_rmx.rmx_mtu; 1677 1678 maxopd = mtu - 1679 (isipv6 ? 1680 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1681 sizeof(struct tcpiphdr)); 1682 1683 /* 1684 * XXX - The following conditional probably violates the TCP 1685 * spec. The problem is that, since we don't know the 1686 * other end's MSS, we are supposed to use a conservative 1687 * default. But, if we do that, then MTU discovery will 1688 * never actually take place, because the conservative 1689 * default is much less than the MTUs typically seen 1690 * on the Internet today. For the moment, we'll sweep 1691 * this under the carpet. 1692 * 1693 * The conservative default might not actually be a problem 1694 * if the only case this occurs is when sending an initial 1695 * SYN with options and data to a host we've never talked 1696 * to before. Then, they will reply with an MSS value which 1697 * will get recorded and the new parameters should get 1698 * recomputed. For Further Study. 1699 */ 1700 if (rt->rt_rmx.rmx_mssopt && rt->rt_rmx.rmx_mssopt < maxopd) 1701 maxopd = rt->rt_rmx.rmx_mssopt; 1702 } else 1703 maxopd = mtu - 1704 (isipv6 ? 1705 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1706 sizeof(struct tcpiphdr)); 1707 1708 if (tp->t_maxopd <= maxopd) 1709 return; 1710 tp->t_maxopd = maxopd; 1711 1712 mss = maxopd; 1713 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) == 1714 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1715 mss -= TCPOLEN_TSTAMP_APPA; 1716 1717 /* round down to multiple of MCLBYTES */ 1718 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */ 1719 if (mss > MCLBYTES) 1720 mss &= ~(MCLBYTES - 1); 1721 #else 1722 if (mss > MCLBYTES) 1723 mss = (mss / MCLBYTES) * MCLBYTES; 1724 #endif 1725 1726 if (so->so_snd.ssb_hiwat < mss) 1727 mss = so->so_snd.ssb_hiwat; 1728 1729 tp->t_maxseg = mss; 1730 tp->t_rtttime = 0; 1731 tp->snd_nxt = tp->snd_una; 1732 tcp_output(tp); 1733 tcpstat.tcps_mturesent++; 1734 } 1735 1736 /* 1737 * Look-up the routing entry to the peer of this inpcb. If no route 1738 * is found and it cannot be allocated the return NULL. This routine 1739 * is called by TCP routines that access the rmx structure and by tcp_mss 1740 * to get the interface MTU. 1741 */ 1742 struct rtentry * 1743 tcp_rtlookup(struct in_conninfo *inc) 1744 { 1745 struct route *ro = &inc->inc_route; 1746 1747 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) { 1748 /* No route yet, so try to acquire one */ 1749 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1750 /* 1751 * unused portions of the structure MUST be zero'd 1752 * out because rtalloc() treats it as opaque data 1753 */ 1754 bzero(&ro->ro_dst, sizeof(struct sockaddr_in)); 1755 ro->ro_dst.sa_family = AF_INET; 1756 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1757 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1758 inc->inc_faddr; 1759 rtalloc(ro); 1760 } 1761 } 1762 return (ro->ro_rt); 1763 } 1764 1765 #ifdef INET6 1766 struct rtentry * 1767 tcp_rtlookup6(struct in_conninfo *inc) 1768 { 1769 struct route_in6 *ro6 = &inc->inc6_route; 1770 1771 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) { 1772 /* No route yet, so try to acquire one */ 1773 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1774 /* 1775 * unused portions of the structure MUST be zero'd 1776 * out because rtalloc() treats it as opaque data 1777 */ 1778 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6)); 1779 ro6->ro_dst.sin6_family = AF_INET6; 1780 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1781 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1782 rtalloc((struct route *)ro6); 1783 } 1784 } 1785 return (ro6->ro_rt); 1786 } 1787 #endif 1788 1789 #ifdef IPSEC 1790 /* compute ESP/AH header size for TCP, including outer IP header. */ 1791 size_t 1792 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1793 { 1794 struct inpcb *inp; 1795 struct mbuf *m; 1796 size_t hdrsiz; 1797 struct ip *ip; 1798 struct tcphdr *th; 1799 1800 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1801 return (0); 1802 MGETHDR(m, MB_DONTWAIT, MT_DATA); 1803 if (!m) 1804 return (0); 1805 1806 #ifdef INET6 1807 if (inp->inp_vflag & INP_IPV6) { 1808 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 1809 1810 th = (struct tcphdr *)(ip6 + 1); 1811 m->m_pkthdr.len = m->m_len = 1812 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1813 tcp_fillheaders(tp, ip6, th, FALSE); 1814 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1815 } else 1816 #endif 1817 { 1818 ip = mtod(m, struct ip *); 1819 th = (struct tcphdr *)(ip + 1); 1820 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1821 tcp_fillheaders(tp, ip, th, FALSE); 1822 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1823 } 1824 1825 m_free(m); 1826 return (hdrsiz); 1827 } 1828 #endif 1829 1830 /* 1831 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1832 * 1833 * This code attempts to calculate the bandwidth-delay product as a 1834 * means of determining the optimal window size to maximize bandwidth, 1835 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1836 * routers. This code also does a fairly good job keeping RTTs in check 1837 * across slow links like modems. We implement an algorithm which is very 1838 * similar (but not meant to be) TCP/Vegas. The code operates on the 1839 * transmitter side of a TCP connection and so only effects the transmit 1840 * side of the connection. 1841 * 1842 * BACKGROUND: TCP makes no provision for the management of buffer space 1843 * at the end points or at the intermediate routers and switches. A TCP 1844 * stream, whether using NewReno or not, will eventually buffer as 1845 * many packets as it is able and the only reason this typically works is 1846 * due to the fairly small default buffers made available for a connection 1847 * (typicaly 16K or 32K). As machines use larger windows and/or window 1848 * scaling it is now fairly easy for even a single TCP connection to blow-out 1849 * all available buffer space not only on the local interface, but on 1850 * intermediate routers and switches as well. NewReno makes a misguided 1851 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1852 * then backing off, then steadily increasing the window again until another 1853 * failure occurs, ad-infinitum. This results in terrible oscillation that 1854 * is only made worse as network loads increase and the idea of intentionally 1855 * blowing out network buffers is, frankly, a terrible way to manage network 1856 * resources. 1857 * 1858 * It is far better to limit the transmit window prior to the failure 1859 * condition being achieved. There are two general ways to do this: First 1860 * you can 'scan' through different transmit window sizes and locate the 1861 * point where the RTT stops increasing, indicating that you have filled the 1862 * pipe, then scan backwards until you note that RTT stops decreasing, then 1863 * repeat ad-infinitum. This method works in principle but has severe 1864 * implementation issues due to RTT variances, timer granularity, and 1865 * instability in the algorithm which can lead to many false positives and 1866 * create oscillations as well as interact badly with other TCP streams 1867 * implementing the same algorithm. 1868 * 1869 * The second method is to limit the window to the bandwidth delay product 1870 * of the link. This is the method we implement. RTT variances and our 1871 * own manipulation of the congestion window, bwnd, can potentially 1872 * destabilize the algorithm. For this reason we have to stabilize the 1873 * elements used to calculate the window. We do this by using the minimum 1874 * observed RTT, the long term average of the observed bandwidth, and 1875 * by adding two segments worth of slop. It isn't perfect but it is able 1876 * to react to changing conditions and gives us a very stable basis on 1877 * which to extend the algorithm. 1878 */ 1879 void 1880 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1881 { 1882 u_long bw; 1883 u_long bwnd; 1884 int save_ticks; 1885 int delta_ticks; 1886 1887 /* 1888 * If inflight_enable is disabled in the middle of a tcp connection, 1889 * make sure snd_bwnd is effectively disabled. 1890 */ 1891 if (!tcp_inflight_enable) { 1892 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1893 tp->snd_bandwidth = 0; 1894 return; 1895 } 1896 1897 /* 1898 * Validate the delta time. If a connection is new or has been idle 1899 * a long time we have to reset the bandwidth calculator. 1900 */ 1901 save_ticks = ticks; 1902 delta_ticks = save_ticks - tp->t_bw_rtttime; 1903 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) { 1904 tp->t_bw_rtttime = ticks; 1905 tp->t_bw_rtseq = ack_seq; 1906 if (tp->snd_bandwidth == 0) 1907 tp->snd_bandwidth = tcp_inflight_min; 1908 return; 1909 } 1910 if (delta_ticks == 0) 1911 return; 1912 1913 /* 1914 * Sanity check, plus ignore pure window update acks. 1915 */ 1916 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0) 1917 return; 1918 1919 /* 1920 * Figure out the bandwidth. Due to the tick granularity this 1921 * is a very rough number and it MUST be averaged over a fairly 1922 * long period of time. XXX we need to take into account a link 1923 * that is not using all available bandwidth, but for now our 1924 * slop will ramp us up if this case occurs and the bandwidth later 1925 * increases. 1926 */ 1927 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks; 1928 tp->t_bw_rtttime = save_ticks; 1929 tp->t_bw_rtseq = ack_seq; 1930 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1931 1932 tp->snd_bandwidth = bw; 1933 1934 /* 1935 * Calculate the semi-static bandwidth delay product, plus two maximal 1936 * segments. The additional slop puts us squarely in the sweet 1937 * spot and also handles the bandwidth run-up case. Without the 1938 * slop we could be locking ourselves into a lower bandwidth. 1939 * 1940 * Situations Handled: 1941 * (1) Prevents over-queueing of packets on LANs, especially on 1942 * high speed LANs, allowing larger TCP buffers to be 1943 * specified, and also does a good job preventing 1944 * over-queueing of packets over choke points like modems 1945 * (at least for the transmit side). 1946 * 1947 * (2) Is able to handle changing network loads (bandwidth 1948 * drops so bwnd drops, bandwidth increases so bwnd 1949 * increases). 1950 * 1951 * (3) Theoretically should stabilize in the face of multiple 1952 * connections implementing the same algorithm (this may need 1953 * a little work). 1954 * 1955 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1956 * be adjusted with a sysctl but typically only needs to be on 1957 * very slow connections. A value no smaller then 5 should 1958 * be used, but only reduce this default if you have no other 1959 * choice. 1960 */ 1961 1962 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1963 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + 1964 tcp_inflight_stab * (int)tp->t_maxseg / 10; 1965 #undef USERTT 1966 1967 if (tcp_inflight_debug > 0) { 1968 static int ltime; 1969 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1970 ltime = ticks; 1971 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1972 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd); 1973 } 1974 } 1975 if ((long)bwnd < tcp_inflight_min) 1976 bwnd = tcp_inflight_min; 1977 if (bwnd > tcp_inflight_max) 1978 bwnd = tcp_inflight_max; 1979 if ((long)bwnd < tp->t_maxseg * 2) 1980 bwnd = tp->t_maxseg * 2; 1981 tp->snd_bwnd = bwnd; 1982 } 1983 1984 static void 1985 tcp_rmx_iwsegs(struct tcpcb *tp, u_long *maxsegs, u_long *capsegs) 1986 { 1987 struct rtentry *rt; 1988 struct inpcb *inp = tp->t_inpcb; 1989 #ifdef INET6 1990 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) ? TRUE : FALSE); 1991 #else 1992 const boolean_t isipv6 = FALSE; 1993 #endif 1994 1995 /* XXX */ 1996 if (tcp_iw_maxsegs < TCP_IW_MAXSEGS_DFLT) 1997 tcp_iw_maxsegs = TCP_IW_MAXSEGS_DFLT; 1998 if (tcp_iw_capsegs < TCP_IW_CAPSEGS_DFLT) 1999 tcp_iw_capsegs = TCP_IW_CAPSEGS_DFLT; 2000 2001 if (isipv6) 2002 rt = tcp_rtlookup6(&inp->inp_inc); 2003 else 2004 rt = tcp_rtlookup(&inp->inp_inc); 2005 if (rt == NULL || 2006 rt->rt_rmx.rmx_iwmaxsegs < TCP_IW_MAXSEGS_DFLT || 2007 rt->rt_rmx.rmx_iwcapsegs < TCP_IW_CAPSEGS_DFLT) { 2008 *maxsegs = tcp_iw_maxsegs; 2009 *capsegs = tcp_iw_capsegs; 2010 return; 2011 } 2012 *maxsegs = rt->rt_rmx.rmx_iwmaxsegs; 2013 *capsegs = rt->rt_rmx.rmx_iwcapsegs; 2014 } 2015 2016 u_long 2017 tcp_initial_window(struct tcpcb *tp) 2018 { 2019 if (tcp_do_rfc3390) { 2020 /* 2021 * RFC3390: 2022 * "If the SYN or SYN/ACK is lost, the initial window 2023 * used by a sender after a correctly transmitted SYN 2024 * MUST be one segment consisting of MSS bytes." 2025 * 2026 * However, we do something a little bit more aggressive 2027 * then RFC3390 here: 2028 * - Only if time spent in the SYN or SYN|ACK retransmition 2029 * >= 3 seconds, the IW is reduced. We do this mainly 2030 * because when RFC3390 is published, the initial RTO is 2031 * still 3 seconds (the threshold we test here), while 2032 * after RFC6298, the initial RTO is 1 second. This 2033 * behaviour probably still falls within the spirit of 2034 * RFC3390. 2035 * - When IW is reduced, 2*MSS is used instead of 1*MSS. 2036 * Mainly to avoid sender and receiver deadlock until 2037 * delayed ACK timer expires. And even RFC2581 does not 2038 * try to reduce IW upon SYN or SYN|ACK retransmition 2039 * timeout. 2040 * 2041 * See also: 2042 * http://tools.ietf.org/html/draft-ietf-tcpm-initcwnd-03 2043 */ 2044 if (tp->t_rxtsyn >= TCPTV_RTOBASE3) { 2045 return (2 * tp->t_maxseg); 2046 } else { 2047 u_long maxsegs, capsegs; 2048 2049 tcp_rmx_iwsegs(tp, &maxsegs, &capsegs); 2050 return min(maxsegs * tp->t_maxseg, 2051 max(2 * tp->t_maxseg, capsegs * 1460)); 2052 } 2053 } else { 2054 /* 2055 * Even RFC2581 (back to 1999) allows 2*SMSS IW. 2056 * 2057 * Mainly to avoid sender and receiver deadlock 2058 * until delayed ACK timer expires. 2059 */ 2060 return (2 * tp->t_maxseg); 2061 } 2062 } 2063 2064 #ifdef TCP_SIGNATURE 2065 /* 2066 * Compute TCP-MD5 hash of a TCP segment. (RFC2385) 2067 * 2068 * We do this over ip, tcphdr, segment data, and the key in the SADB. 2069 * When called from tcp_input(), we can be sure that th_sum has been 2070 * zeroed out and verified already. 2071 * 2072 * Return 0 if successful, otherwise return -1. 2073 * 2074 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 2075 * search with the destination IP address, and a 'magic SPI' to be 2076 * determined by the application. This is hardcoded elsewhere to 1179 2077 * right now. Another branch of this code exists which uses the SPD to 2078 * specify per-application flows but it is unstable. 2079 */ 2080 int 2081 tcpsignature_compute( 2082 struct mbuf *m, /* mbuf chain */ 2083 int len, /* length of TCP data */ 2084 int optlen, /* length of TCP options */ 2085 u_char *buf, /* storage for MD5 digest */ 2086 u_int direction) /* direction of flow */ 2087 { 2088 struct ippseudo ippseudo; 2089 MD5_CTX ctx; 2090 int doff; 2091 struct ip *ip; 2092 struct ipovly *ipovly; 2093 struct secasvar *sav; 2094 struct tcphdr *th; 2095 #ifdef INET6 2096 struct ip6_hdr *ip6; 2097 struct in6_addr in6; 2098 uint32_t plen; 2099 uint16_t nhdr; 2100 #endif /* INET6 */ 2101 u_short savecsum; 2102 2103 KASSERT(m != NULL, ("passed NULL mbuf. Game over.")); 2104 KASSERT(buf != NULL, ("passed NULL storage pointer for MD5 signature")); 2105 /* 2106 * Extract the destination from the IP header in the mbuf. 2107 */ 2108 ip = mtod(m, struct ip *); 2109 #ifdef INET6 2110 ip6 = NULL; /* Make the compiler happy. */ 2111 #endif /* INET6 */ 2112 /* 2113 * Look up an SADB entry which matches the address found in 2114 * the segment. 2115 */ 2116 switch (IP_VHL_V(ip->ip_vhl)) { 2117 case IPVERSION: 2118 sav = key_allocsa(AF_INET, (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst, 2119 IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2120 break; 2121 #ifdef INET6 2122 case (IPV6_VERSION >> 4): 2123 ip6 = mtod(m, struct ip6_hdr *); 2124 sav = key_allocsa(AF_INET6, (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst, 2125 IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2126 break; 2127 #endif /* INET6 */ 2128 default: 2129 return (EINVAL); 2130 /* NOTREACHED */ 2131 break; 2132 } 2133 if (sav == NULL) { 2134 kprintf("%s: SADB lookup failed\n", __func__); 2135 return (EINVAL); 2136 } 2137 MD5Init(&ctx); 2138 2139 /* 2140 * Step 1: Update MD5 hash with IP pseudo-header. 2141 * 2142 * XXX The ippseudo header MUST be digested in network byte order, 2143 * or else we'll fail the regression test. Assume all fields we've 2144 * been doing arithmetic on have been in host byte order. 2145 * XXX One cannot depend on ipovly->ih_len here. When called from 2146 * tcp_output(), the underlying ip_len member has not yet been set. 2147 */ 2148 switch (IP_VHL_V(ip->ip_vhl)) { 2149 case IPVERSION: 2150 ipovly = (struct ipovly *)ip; 2151 ippseudo.ippseudo_src = ipovly->ih_src; 2152 ippseudo.ippseudo_dst = ipovly->ih_dst; 2153 ippseudo.ippseudo_pad = 0; 2154 ippseudo.ippseudo_p = IPPROTO_TCP; 2155 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + optlen); 2156 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2157 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip)); 2158 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen; 2159 break; 2160 #ifdef INET6 2161 /* 2162 * RFC 2385, 2.0 Proposal 2163 * For IPv6, the pseudo-header is as described in RFC 2460, namely the 2164 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero- 2165 * extended next header value (to form 32 bits), and 32-bit segment 2166 * length. 2167 * Note: Upper-Layer Packet Length comes before Next Header. 2168 */ 2169 case (IPV6_VERSION >> 4): 2170 in6 = ip6->ip6_src; 2171 in6_clearscope(&in6); 2172 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2173 in6 = ip6->ip6_dst; 2174 in6_clearscope(&in6); 2175 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2176 plen = htonl(len + sizeof(struct tcphdr) + optlen); 2177 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t)); 2178 nhdr = 0; 2179 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2180 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2181 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2182 nhdr = IPPROTO_TCP; 2183 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2184 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr)); 2185 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen; 2186 break; 2187 #endif /* INET6 */ 2188 default: 2189 return (EINVAL); 2190 /* NOTREACHED */ 2191 break; 2192 } 2193 /* 2194 * Step 2: Update MD5 hash with TCP header, excluding options. 2195 * The TCP checksum must be set to zero. 2196 */ 2197 savecsum = th->th_sum; 2198 th->th_sum = 0; 2199 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2200 th->th_sum = savecsum; 2201 /* 2202 * Step 3: Update MD5 hash with TCP segment data. 2203 * Use m_apply() to avoid an early m_pullup(). 2204 */ 2205 if (len > 0) 2206 m_apply(m, doff, len, tcpsignature_apply, &ctx); 2207 /* 2208 * Step 4: Update MD5 hash with shared secret. 2209 */ 2210 MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); 2211 MD5Final(buf, &ctx); 2212 key_sa_recordxfer(sav, m); 2213 key_freesav(sav); 2214 return (0); 2215 } 2216 2217 int 2218 tcpsignature_apply(void *fstate, void *data, unsigned int len) 2219 { 2220 2221 MD5Update((MD5_CTX *)fstate, (unsigned char *)data, len); 2222 return (0); 2223 } 2224 #endif /* TCP_SIGNATURE */ 2225 2226 boolean_t 2227 tcp_tso_pullup(struct mbuf **mp, int hoff, struct ip **ip0, int *iphlen0, 2228 struct tcphdr **th0, int *thoff0) 2229 { 2230 struct mbuf *m = *mp; 2231 struct ip *ip; 2232 int len, iphlen; 2233 struct tcphdr *th; 2234 int thoff; 2235 2236 len = hoff + sizeof(struct ip); 2237 2238 /* The fixed IP header must reside completely in the first mbuf. */ 2239 if (m->m_len < len) { 2240 m = m_pullup(m, len); 2241 if (m == NULL) 2242 goto fail; 2243 } 2244 2245 ip = mtodoff(m, struct ip *, hoff); 2246 iphlen = IP_VHL_HL(ip->ip_vhl) << 2; 2247 2248 /* The full IP header must reside completely in the one mbuf. */ 2249 if (m->m_len < hoff + iphlen) { 2250 m = m_pullup(m, hoff + iphlen); 2251 if (m == NULL) 2252 goto fail; 2253 ip = mtodoff(m, struct ip *, hoff); 2254 } 2255 2256 KASSERT(ip->ip_p == IPPROTO_TCP, ("not tcp %d", ip->ip_p)); 2257 2258 if (m->m_len < hoff + iphlen + sizeof(struct tcphdr)) { 2259 m = m_pullup(m, hoff + iphlen + sizeof(struct tcphdr)); 2260 if (m == NULL) 2261 goto fail; 2262 ip = mtodoff(m, struct ip *, hoff); 2263 } 2264 2265 th = (struct tcphdr *)((caddr_t)ip + iphlen); 2266 thoff = th->th_off << 2; 2267 2268 if (m->m_len < hoff + iphlen + thoff) { 2269 m = m_pullup(m, hoff + iphlen + thoff); 2270 if (m == NULL) 2271 goto fail; 2272 ip = mtodoff(m, struct ip *, hoff); 2273 th = (struct tcphdr *)((caddr_t)ip + iphlen); 2274 } 2275 2276 *mp = m; 2277 *ip0 = ip; 2278 *iphlen0 = iphlen; 2279 *th0 = th; 2280 *thoff0 = thoff; 2281 return TRUE; 2282 2283 fail: 2284 if (m != NULL) 2285 m_freem(m); 2286 *mp = NULL; 2287 return FALSE; 2288 } 2289