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) 2003, 2004 Jeffrey M. Hsu. All rights reserved. 36 * 37 * License terms: all terms for the DragonFly license above plus the following: 38 * 39 * 4. All advertising materials mentioning features or use of this software 40 * must display the following acknowledgement: 41 * 42 * This product includes software developed by Jeffrey M. Hsu 43 * for the DragonFly Project. 44 * 45 * This requirement may be waived with permission from Jeffrey Hsu. 46 * This requirement will sunset and may be removed on July 8 2005, 47 * after which the standard DragonFly license (as shown above) will 48 * apply. 49 */ 50 51 /* 52 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 53 * The Regents of the University of California. All rights reserved. 54 * 55 * Redistribution and use in source and binary forms, with or without 56 * modification, are permitted provided that the following conditions 57 * are met: 58 * 1. Redistributions of source code must retain the above copyright 59 * notice, this list of conditions and the following disclaimer. 60 * 2. Redistributions in binary form must reproduce the above copyright 61 * notice, this list of conditions and the following disclaimer in the 62 * documentation and/or other materials provided with the distribution. 63 * 3. All advertising materials mentioning features or use of this software 64 * must display the following acknowledgement: 65 * This product includes software developed by the University of 66 * California, Berkeley and its contributors. 67 * 4. Neither the name of the University nor the names of its contributors 68 * may be used to endorse or promote products derived from this software 69 * without specific prior written permission. 70 * 71 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 72 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 73 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 74 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 75 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 76 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 77 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 78 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 79 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 80 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 81 * SUCH DAMAGE. 82 * 83 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 84 * $FreeBSD: src/sys/netinet/tcp_subr.c,v 1.73.2.31 2003/01/24 05:11:34 sam Exp $ 85 * $DragonFly: src/sys/netinet/tcp_subr.c,v 1.51 2006/01/14 11:33:50 swildner Exp $ 86 */ 87 88 #include "opt_compat.h" 89 #include "opt_inet6.h" 90 #include "opt_ipsec.h" 91 #include "opt_tcpdebug.h" 92 93 #include <sys/param.h> 94 #include <sys/systm.h> 95 #include <sys/callout.h> 96 #include <sys/kernel.h> 97 #include <sys/sysctl.h> 98 #include <sys/malloc.h> 99 #include <sys/mpipe.h> 100 #include <sys/mbuf.h> 101 #ifdef INET6 102 #include <sys/domain.h> 103 #endif 104 #include <sys/proc.h> 105 #include <sys/socket.h> 106 #include <sys/socketvar.h> 107 #include <sys/protosw.h> 108 #include <sys/random.h> 109 #include <sys/in_cksum.h> 110 #include <sys/ktr.h> 111 112 #include <vm/vm_zone.h> 113 114 #include <net/route.h> 115 #include <net/if.h> 116 #include <net/netisr.h> 117 118 #define _IP_VHL 119 #include <netinet/in.h> 120 #include <netinet/in_systm.h> 121 #include <netinet/ip.h> 122 #include <netinet/ip6.h> 123 #include <netinet/in_pcb.h> 124 #include <netinet6/in6_pcb.h> 125 #include <netinet/in_var.h> 126 #include <netinet/ip_var.h> 127 #include <netinet6/ip6_var.h> 128 #include <netinet/ip_icmp.h> 129 #ifdef INET6 130 #include <netinet/icmp6.h> 131 #endif 132 #include <netinet/tcp.h> 133 #include <netinet/tcp_fsm.h> 134 #include <netinet/tcp_seq.h> 135 #include <netinet/tcp_timer.h> 136 #include <netinet/tcp_var.h> 137 #include <netinet6/tcp6_var.h> 138 #include <netinet/tcpip.h> 139 #ifdef TCPDEBUG 140 #include <netinet/tcp_debug.h> 141 #endif 142 #include <netinet6/ip6protosw.h> 143 144 #ifdef IPSEC 145 #include <netinet6/ipsec.h> 146 #ifdef INET6 147 #include <netinet6/ipsec6.h> 148 #endif 149 #endif 150 151 #ifdef FAST_IPSEC 152 #include <netproto/ipsec/ipsec.h> 153 #ifdef INET6 154 #include <netproto/ipsec/ipsec6.h> 155 #endif 156 #define IPSEC 157 #endif 158 159 #include <sys/md5.h> 160 #include <sys/msgport2.h> 161 #include <machine/smp.h> 162 163 #if !defined(KTR_TCP) 164 #define KTR_TCP KTR_ALL 165 #endif 166 KTR_INFO_MASTER(tcp); 167 KTR_INFO(KTR_TCP, tcp, rxmsg, 0, "tcp getmsg", 0); 168 KTR_INFO(KTR_TCP, tcp, wait, 1, "tcp waitmsg", 0); 169 KTR_INFO(KTR_TCP, tcp, delayed, 2, "tcp execute delayed ops", 0); 170 #define logtcp(name) KTR_LOG(tcp_ ## name) 171 172 struct inpcbinfo tcbinfo[MAXCPU]; 173 struct tcpcbackqhead tcpcbackq[MAXCPU]; 174 175 int tcp_mssdflt = TCP_MSS; 176 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 177 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size"); 178 179 #ifdef INET6 180 int tcp_v6mssdflt = TCP6_MSS; 181 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW, 182 &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6"); 183 #endif 184 185 #if 0 186 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 187 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 188 &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time"); 189 #endif 190 191 int tcp_do_rfc1323 = 1; 192 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 193 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions"); 194 195 int tcp_do_rfc1644 = 0; 196 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 197 &tcp_do_rfc1644, 0, "Enable rfc1644 (TTCP) extensions"); 198 199 static int tcp_tcbhashsize = 0; 200 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 201 &tcp_tcbhashsize, 0, "Size of TCP control block hashtable"); 202 203 static int do_tcpdrain = 1; 204 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 205 "Enable tcp_drain routine for extra help when low on mbufs"); 206 207 /* XXX JH */ 208 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 209 &tcbinfo[0].ipi_count, 0, "Number of active PCBs"); 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. Note that the default lower bound of 221 * 1024 exists only for debugging. A good production default would be 222 * something like 6100. 223 */ 224 static int tcp_inflight_enable = 0; 225 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW, 226 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 227 228 static int tcp_inflight_debug = 0; 229 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW, 230 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 231 232 static int tcp_inflight_min = 6144; 233 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW, 234 &tcp_inflight_min, 0, "Lower bound for TCP inflight window"); 235 236 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 237 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW, 238 &tcp_inflight_max, 0, "Upper bound for TCP inflight window"); 239 240 static int tcp_inflight_stab = 20; 241 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW, 242 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 2 packets)"); 243 244 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives"); 245 static struct malloc_pipe tcptemp_mpipe; 246 247 static void tcp_willblock(void); 248 static void tcp_cleartaocache (void); 249 static void tcp_notify (struct inpcb *, int); 250 251 struct tcp_stats tcpstats_percpu[MAXCPU]; 252 #ifdef SMP 253 static int 254 sysctl_tcpstats(SYSCTL_HANDLER_ARGS) 255 { 256 int cpu, error = 0; 257 258 for (cpu = 0; cpu < ncpus; ++cpu) { 259 if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu], 260 sizeof(struct tcp_stats)))) 261 break; 262 if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu], 263 sizeof(struct tcp_stats)))) 264 break; 265 } 266 267 return (error); 268 } 269 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 270 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics"); 271 #else 272 SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW, 273 &tcpstat, tcp_stats, "TCP statistics"); 274 #endif 275 276 /* 277 * Target size of TCP PCB hash tables. Must be a power of two. 278 * 279 * Note that this can be overridden by the kernel environment 280 * variable net.inet.tcp.tcbhashsize 281 */ 282 #ifndef TCBHASHSIZE 283 #define TCBHASHSIZE 512 284 #endif 285 286 /* 287 * This is the actual shape of what we allocate using the zone 288 * allocator. Doing it this way allows us to protect both structures 289 * using the same generation count, and also eliminates the overhead 290 * of allocating tcpcbs separately. By hiding the structure here, 291 * we avoid changing most of the rest of the code (although it needs 292 * to be changed, eventually, for greater efficiency). 293 */ 294 #define ALIGNMENT 32 295 #define ALIGNM1 (ALIGNMENT - 1) 296 struct inp_tp { 297 union { 298 struct inpcb inp; 299 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 300 } inp_tp_u; 301 struct tcpcb tcb; 302 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl; 303 struct callout inp_tp_delack; 304 }; 305 #undef ALIGNMENT 306 #undef ALIGNM1 307 308 /* 309 * Tcp initialization 310 */ 311 void 312 tcp_init(void) 313 { 314 struct inpcbporthead *porthashbase; 315 u_long porthashmask; 316 struct vm_zone *ipi_zone; 317 int hashsize = TCBHASHSIZE; 318 int cpu; 319 320 /* 321 * note: tcptemp is used for keepalives, and it is ok for an 322 * allocation to fail so do not specify MPF_INT. 323 */ 324 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp), 325 25, -1, 0, NULL); 326 327 tcp_ccgen = 1; 328 tcp_cleartaocache(); 329 330 tcp_delacktime = TCPTV_DELACK; 331 tcp_keepinit = TCPTV_KEEP_INIT; 332 tcp_keepidle = TCPTV_KEEP_IDLE; 333 tcp_keepintvl = TCPTV_KEEPINTVL; 334 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 335 tcp_msl = TCPTV_MSL; 336 tcp_rexmit_min = TCPTV_MIN; 337 tcp_rexmit_slop = TCPTV_CPU_VAR; 338 339 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 340 if (!powerof2(hashsize)) { 341 printf("WARNING: TCB hash size not a power of 2\n"); 342 hashsize = 512; /* safe default */ 343 } 344 tcp_tcbhashsize = hashsize; 345 porthashbase = hashinit(hashsize, M_PCB, &porthashmask); 346 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 347 ZONE_INTERRUPT, 0); 348 349 for (cpu = 0; cpu < ncpus2; cpu++) { 350 in_pcbinfo_init(&tcbinfo[cpu]); 351 tcbinfo[cpu].cpu = cpu; 352 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB, 353 &tcbinfo[cpu].hashmask); 354 tcbinfo[cpu].porthashbase = porthashbase; 355 tcbinfo[cpu].porthashmask = porthashmask; 356 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB, 357 &tcbinfo[cpu].wildcardhashmask); 358 tcbinfo[cpu].ipi_zone = ipi_zone; 359 TAILQ_INIT(&tcpcbackq[cpu]); 360 } 361 362 tcp_reass_maxseg = nmbclusters / 16; 363 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg); 364 365 #ifdef INET6 366 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 367 #else 368 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 369 #endif 370 if (max_protohdr < TCP_MINPROTOHDR) 371 max_protohdr = TCP_MINPROTOHDR; 372 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 373 panic("tcp_init"); 374 #undef TCP_MINPROTOHDR 375 376 /* 377 * Initialize TCP statistics counters for each CPU. 378 */ 379 #ifdef SMP 380 for (cpu = 0; cpu < ncpus; ++cpu) { 381 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats)); 382 } 383 #else 384 bzero(&tcpstat, sizeof(struct tcp_stats)); 385 #endif 386 387 syncache_init(); 388 tcp_sack_init(); 389 tcp_thread_init(); 390 } 391 392 void 393 tcpmsg_service_loop(void *dummy) 394 { 395 struct netmsg *msg; 396 397 while ((msg = lwkt_waitport(&curthread->td_msgport, NULL))) { 398 do { 399 logtcp(rxmsg); 400 msg->nm_lmsg.ms_cmd.cm_func(&msg->nm_lmsg); 401 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL); 402 logtcp(delayed); 403 tcp_willblock(); 404 logtcp(wait); 405 } 406 } 407 408 static void 409 tcp_willblock(void) 410 { 411 struct tcpcb *tp; 412 int cpu = mycpu->gd_cpuid; 413 414 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) { 415 KKASSERT(tp->t_flags & TF_ONOUTPUTQ); 416 tp->t_flags &= ~TF_ONOUTPUTQ; 417 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq); 418 tcp_output(tp); 419 } 420 } 421 422 423 /* 424 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 425 * tcp_template used to store this data in mbufs, but we now recopy it out 426 * of the tcpcb each time to conserve mbufs. 427 */ 428 void 429 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr) 430 { 431 struct inpcb *inp = tp->t_inpcb; 432 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 433 434 #ifdef INET6 435 if (inp->inp_vflag & INP_IPV6) { 436 struct ip6_hdr *ip6; 437 438 ip6 = (struct ip6_hdr *)ip_ptr; 439 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 440 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 441 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 442 (IPV6_VERSION & IPV6_VERSION_MASK); 443 ip6->ip6_nxt = IPPROTO_TCP; 444 ip6->ip6_plen = sizeof(struct tcphdr); 445 ip6->ip6_src = inp->in6p_laddr; 446 ip6->ip6_dst = inp->in6p_faddr; 447 tcp_hdr->th_sum = 0; 448 } else 449 #endif 450 { 451 struct ip *ip = (struct ip *) ip_ptr; 452 453 ip->ip_vhl = IP_VHL_BORING; 454 ip->ip_tos = 0; 455 ip->ip_len = 0; 456 ip->ip_id = 0; 457 ip->ip_off = 0; 458 ip->ip_ttl = 0; 459 ip->ip_sum = 0; 460 ip->ip_p = IPPROTO_TCP; 461 ip->ip_src = inp->inp_laddr; 462 ip->ip_dst = inp->inp_faddr; 463 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, 464 ip->ip_dst.s_addr, 465 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 466 } 467 468 tcp_hdr->th_sport = inp->inp_lport; 469 tcp_hdr->th_dport = inp->inp_fport; 470 tcp_hdr->th_seq = 0; 471 tcp_hdr->th_ack = 0; 472 tcp_hdr->th_x2 = 0; 473 tcp_hdr->th_off = 5; 474 tcp_hdr->th_flags = 0; 475 tcp_hdr->th_win = 0; 476 tcp_hdr->th_urp = 0; 477 } 478 479 /* 480 * Create template to be used to send tcp packets on a connection. 481 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 482 * use for this function is in keepalives, which use tcp_respond. 483 */ 484 struct tcptemp * 485 tcp_maketemplate(struct tcpcb *tp) 486 { 487 struct tcptemp *tmp; 488 489 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL) 490 return (NULL); 491 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t); 492 return (tmp); 493 } 494 495 void 496 tcp_freetemplate(struct tcptemp *tmp) 497 { 498 mpipe_free(&tcptemp_mpipe, tmp); 499 } 500 501 /* 502 * Send a single message to the TCP at address specified by 503 * the given TCP/IP header. If m == NULL, then we make a copy 504 * of the tcpiphdr at ti and send directly to the addressed host. 505 * This is used to force keep alive messages out using the TCP 506 * template for a connection. If flags are given then we send 507 * a message back to the TCP which originated the * segment ti, 508 * and discard the mbuf containing it and any other attached mbufs. 509 * 510 * In any case the ack and sequence number of the transmitted 511 * segment are as specified by the parameters. 512 * 513 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 514 */ 515 void 516 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 517 tcp_seq ack, tcp_seq seq, int flags) 518 { 519 int tlen; 520 int win = 0; 521 struct route *ro = NULL; 522 struct route sro; 523 struct ip *ip = ipgen; 524 struct tcphdr *nth; 525 int ipflags = 0; 526 struct route_in6 *ro6 = NULL; 527 struct route_in6 sro6; 528 struct ip6_hdr *ip6 = ipgen; 529 #ifdef INET6 530 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6); 531 #else 532 const boolean_t isipv6 = FALSE; 533 #endif 534 535 if (tp != NULL) { 536 if (!(flags & TH_RST)) { 537 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 538 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 539 win = (long)TCP_MAXWIN << tp->rcv_scale; 540 } 541 if (isipv6) 542 ro6 = &tp->t_inpcb->in6p_route; 543 else 544 ro = &tp->t_inpcb->inp_route; 545 } else { 546 if (isipv6) { 547 ro6 = &sro6; 548 bzero(ro6, sizeof *ro6); 549 } else { 550 ro = &sro; 551 bzero(ro, sizeof *ro); 552 } 553 } 554 if (m == NULL) { 555 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 556 if (m == NULL) 557 return; 558 tlen = 0; 559 m->m_data += max_linkhdr; 560 if (isipv6) { 561 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr)); 562 ip6 = mtod(m, struct ip6_hdr *); 563 nth = (struct tcphdr *)(ip6 + 1); 564 } else { 565 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); 566 ip = mtod(m, struct ip *); 567 nth = (struct tcphdr *)(ip + 1); 568 } 569 bcopy(th, nth, sizeof(struct tcphdr)); 570 flags = TH_ACK; 571 } else { 572 m_freem(m->m_next); 573 m->m_next = NULL; 574 m->m_data = (caddr_t)ipgen; 575 /* m_len is set later */ 576 tlen = 0; 577 #define xchg(a, b, type) { type t; t = a; a = b; b = t; } 578 if (isipv6) { 579 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 580 nth = (struct tcphdr *)(ip6 + 1); 581 } else { 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 if (isipv6) { 598 ip6->ip6_flow = 0; 599 ip6->ip6_vfc = IPV6_VERSION; 600 ip6->ip6_nxt = IPPROTO_TCP; 601 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen)); 602 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 603 } else { 604 tlen += sizeof(struct tcpiphdr); 605 ip->ip_len = tlen; 606 ip->ip_ttl = ip_defttl; 607 } 608 m->m_len = tlen; 609 m->m_pkthdr.len = tlen; 610 m->m_pkthdr.rcvif = (struct ifnet *) NULL; 611 nth->th_seq = htonl(seq); 612 nth->th_ack = htonl(ack); 613 nth->th_x2 = 0; 614 nth->th_off = sizeof(struct tcphdr) >> 2; 615 nth->th_flags = flags; 616 if (tp != NULL) 617 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 618 else 619 nth->th_win = htons((u_short)win); 620 nth->th_urp = 0; 621 if (isipv6) { 622 nth->th_sum = 0; 623 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 624 sizeof(struct ip6_hdr), 625 tlen - sizeof(struct ip6_hdr)); 626 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 627 (ro6 && ro6->ro_rt) ? 628 ro6->ro_rt->rt_ifp : NULL); 629 } else { 630 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 631 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 632 m->m_pkthdr.csum_flags = CSUM_TCP; 633 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 634 } 635 #ifdef TCPDEBUG 636 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 637 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 638 #endif 639 if (isipv6) { 640 ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 641 tp ? tp->t_inpcb : NULL); 642 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) { 643 RTFREE(ro6->ro_rt); 644 ro6->ro_rt = NULL; 645 } 646 } else { 647 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 648 if ((ro == &sro) && (ro->ro_rt != NULL)) { 649 RTFREE(ro->ro_rt); 650 ro->ro_rt = NULL; 651 } 652 } 653 } 654 655 /* 656 * Create a new TCP control block, making an 657 * empty reassembly queue and hooking it to the argument 658 * protocol control block. The `inp' parameter must have 659 * come from the zone allocator set up in tcp_init(). 660 */ 661 struct tcpcb * 662 tcp_newtcpcb(struct inpcb *inp) 663 { 664 struct inp_tp *it; 665 struct tcpcb *tp; 666 #ifdef INET6 667 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 668 #else 669 const boolean_t isipv6 = FALSE; 670 #endif 671 672 it = (struct inp_tp *)inp; 673 tp = &it->tcb; 674 bzero(tp, sizeof(struct tcpcb)); 675 LIST_INIT(&tp->t_segq); 676 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt; 677 678 /* Set up our timeouts. */ 679 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt); 680 callout_init(tp->tt_persist = &it->inp_tp_persist); 681 callout_init(tp->tt_keep = &it->inp_tp_keep); 682 callout_init(tp->tt_2msl = &it->inp_tp_2msl); 683 callout_init(tp->tt_delack = &it->inp_tp_delack); 684 685 if (tcp_do_rfc1323) 686 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP); 687 if (tcp_do_rfc1644) 688 tp->t_flags |= TF_REQ_CC; 689 tp->t_inpcb = inp; /* XXX */ 690 tp->t_state = TCPS_CLOSED; 691 /* 692 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 693 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 694 * reasonable initial retransmit time. 695 */ 696 tp->t_srtt = TCPTV_SRTTBASE; 697 tp->t_rttvar = 698 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 699 tp->t_rttmin = tcp_rexmit_min; 700 tp->t_rxtcur = TCPTV_RTOBASE; 701 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 702 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 703 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 704 tp->t_rcvtime = ticks; 705 /* 706 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 707 * because the socket may be bound to an IPv6 wildcard address, 708 * which may match an IPv4-mapped IPv6 address. 709 */ 710 inp->inp_ip_ttl = ip_defttl; 711 inp->inp_ppcb = tp; 712 tcp_sack_tcpcb_init(tp); 713 return (tp); /* XXX */ 714 } 715 716 /* 717 * Drop a TCP connection, reporting the specified error. 718 * If connection is synchronized, then send a RST to peer. 719 */ 720 struct tcpcb * 721 tcp_drop(struct tcpcb *tp, int errno) 722 { 723 struct socket *so = tp->t_inpcb->inp_socket; 724 725 if (TCPS_HAVERCVDSYN(tp->t_state)) { 726 tp->t_state = TCPS_CLOSED; 727 tcp_output(tp); 728 tcpstat.tcps_drops++; 729 } else 730 tcpstat.tcps_conndrops++; 731 if (errno == ETIMEDOUT && tp->t_softerror) 732 errno = tp->t_softerror; 733 so->so_error = errno; 734 return (tcp_close(tp)); 735 } 736 737 #ifdef SMP 738 739 struct netmsg_remwildcard { 740 struct lwkt_msg nm_lmsg; 741 struct inpcb *nm_inp; 742 struct inpcbinfo *nm_pcbinfo; 743 #if defined(INET6) 744 int nm_isinet6; 745 #else 746 int nm_unused01; 747 #endif 748 }; 749 750 /* 751 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the 752 * inp can be detached. We do this by cycling through the cpus, ending up 753 * on the cpu controlling the inp last and then doing the disconnect. 754 */ 755 static int 756 in_pcbremwildcardhash_handler(struct lwkt_msg *msg0) 757 { 758 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0; 759 int cpu; 760 761 cpu = msg->nm_pcbinfo->cpu; 762 763 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) { 764 /* note: detach removes any wildcard hash entry */ 765 #ifdef INET6 766 if (msg->nm_isinet6) 767 in6_pcbdetach(msg->nm_inp); 768 else 769 #endif 770 in_pcbdetach(msg->nm_inp); 771 lwkt_replymsg(&msg->nm_lmsg, 0); 772 } else { 773 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo); 774 cpu = (cpu + 1) % ncpus2; 775 msg->nm_pcbinfo = &tcbinfo[cpu]; 776 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_lmsg); 777 } 778 return (EASYNC); 779 } 780 781 #endif 782 783 /* 784 * Close a TCP control block: 785 * discard all space held by the tcp 786 * discard internet protocol block 787 * wake up any sleepers 788 */ 789 struct tcpcb * 790 tcp_close(struct tcpcb *tp) 791 { 792 struct tseg_qent *q; 793 struct inpcb *inp = tp->t_inpcb; 794 struct socket *so = inp->inp_socket; 795 struct rtentry *rt; 796 boolean_t dosavessthresh; 797 #ifdef SMP 798 int cpu; 799 #endif 800 #ifdef INET6 801 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 802 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0); 803 #else 804 const boolean_t isipv6 = FALSE; 805 #endif 806 807 /* 808 * The tp is not instantly destroyed in the wildcard case. Setting 809 * the state to TCPS_TERMINATING will prevent the TCP stack from 810 * messing with it, though it should be noted that this change may 811 * not take effect on other cpus until we have chained the wildcard 812 * hash removal. 813 * 814 * XXX we currently depend on the BGL to synchronize the tp->t_state 815 * update and prevent other tcp protocol threads from accepting new 816 * connections on the listen socket we might be trying to close down. 817 */ 818 KKASSERT(tp->t_state != TCPS_TERMINATING); 819 tp->t_state = TCPS_TERMINATING; 820 821 /* 822 * Make sure that all of our timers are stopped before we 823 * delete the PCB. 824 */ 825 callout_stop(tp->tt_rexmt); 826 callout_stop(tp->tt_persist); 827 callout_stop(tp->tt_keep); 828 callout_stop(tp->tt_2msl); 829 callout_stop(tp->tt_delack); 830 831 if (tp->t_flags & TF_ONOUTPUTQ) { 832 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid); 833 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq); 834 tp->t_flags &= ~TF_ONOUTPUTQ; 835 } 836 837 /* 838 * If we got enough samples through the srtt filter, 839 * save the rtt and rttvar in the routing entry. 840 * 'Enough' is arbitrarily defined as the 16 samples. 841 * 16 samples is enough for the srtt filter to converge 842 * to within 5% of the correct value; fewer samples and 843 * we could save a very bogus rtt. 844 * 845 * Don't update the default route's characteristics and don't 846 * update anything that the user "locked". 847 */ 848 if (tp->t_rttupdated >= 16) { 849 u_long i = 0; 850 851 if (isipv6) { 852 struct sockaddr_in6 *sin6; 853 854 if ((rt = inp->in6p_route.ro_rt) == NULL) 855 goto no_valid_rt; 856 sin6 = (struct sockaddr_in6 *)rt_key(rt); 857 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 858 goto no_valid_rt; 859 } else 860 if ((rt = inp->inp_route.ro_rt) == NULL || 861 ((struct sockaddr_in *)rt_key(rt))-> 862 sin_addr.s_addr == INADDR_ANY) 863 goto no_valid_rt; 864 865 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) { 866 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 867 if (rt->rt_rmx.rmx_rtt && i) 868 /* 869 * filter this update to half the old & half 870 * the new values, converting scale. 871 * See route.h and tcp_var.h for a 872 * description of the scaling constants. 873 */ 874 rt->rt_rmx.rmx_rtt = 875 (rt->rt_rmx.rmx_rtt + i) / 2; 876 else 877 rt->rt_rmx.rmx_rtt = i; 878 tcpstat.tcps_cachedrtt++; 879 } 880 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) { 881 i = tp->t_rttvar * 882 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 883 if (rt->rt_rmx.rmx_rttvar && i) 884 rt->rt_rmx.rmx_rttvar = 885 (rt->rt_rmx.rmx_rttvar + i) / 2; 886 else 887 rt->rt_rmx.rmx_rttvar = i; 888 tcpstat.tcps_cachedrttvar++; 889 } 890 /* 891 * The old comment here said: 892 * update the pipelimit (ssthresh) if it has been updated 893 * already or if a pipesize was specified & the threshhold 894 * got below half the pipesize. I.e., wait for bad news 895 * before we start updating, then update on both good 896 * and bad news. 897 * 898 * But we want to save the ssthresh even if no pipesize is 899 * specified explicitly in the route, because such 900 * connections still have an implicit pipesize specified 901 * by the global tcp_sendspace. In the absence of a reliable 902 * way to calculate the pipesize, it will have to do. 903 */ 904 i = tp->snd_ssthresh; 905 if (rt->rt_rmx.rmx_sendpipe != 0) 906 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2); 907 else 908 dosavessthresh = (i < so->so_snd.sb_hiwat/2); 909 if (dosavessthresh || 910 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) && 911 (rt->rt_rmx.rmx_ssthresh != 0))) { 912 /* 913 * convert the limit from user data bytes to 914 * packets then to packet data bytes. 915 */ 916 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 917 if (i < 2) 918 i = 2; 919 i *= tp->t_maxseg + 920 (isipv6 ? 921 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 922 sizeof(struct tcpiphdr)); 923 if (rt->rt_rmx.rmx_ssthresh) 924 rt->rt_rmx.rmx_ssthresh = 925 (rt->rt_rmx.rmx_ssthresh + i) / 2; 926 else 927 rt->rt_rmx.rmx_ssthresh = i; 928 tcpstat.tcps_cachedssthresh++; 929 } 930 } 931 932 no_valid_rt: 933 /* free the reassembly queue, if any */ 934 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 935 LIST_REMOVE(q, tqe_q); 936 m_freem(q->tqe_m); 937 FREE(q, M_TSEGQ); 938 tcp_reass_qsize--; 939 } 940 /* throw away SACK blocks in scoreboard*/ 941 if (TCP_DO_SACK(tp)) 942 tcp_sack_cleanup(&tp->scb); 943 944 inp->inp_ppcb = NULL; 945 soisdisconnected(so); 946 /* 947 * Discard the inp. In the SMP case a wildcard inp's hash (created 948 * by a listen socket or an INADDR_ANY udp socket) is replicated 949 * for each protocol thread and must be removed in the context of 950 * that thread. This is accomplished by chaining the message 951 * through the cpus. 952 * 953 * If the inp is not wildcarded we simply detach, which will remove 954 * the any hashes still present for this inp. 955 */ 956 #ifdef SMP 957 if (inp->inp_flags & INP_WILDCARD_MP) { 958 struct netmsg_remwildcard *msg; 959 960 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2; 961 msg = malloc(sizeof(struct netmsg_remwildcard), 962 M_LWKTMSG, M_INTWAIT); 963 lwkt_initmsg(&msg->nm_lmsg, &netisr_afree_rport, 0, 964 lwkt_cmd_func(in_pcbremwildcardhash_handler), 965 lwkt_cmd_op_none); 966 #ifdef INET6 967 msg->nm_isinet6 = isafinet6; 968 #endif 969 msg->nm_inp = inp; 970 msg->nm_pcbinfo = &tcbinfo[cpu]; 971 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_lmsg); 972 } else 973 #endif 974 { 975 /* note: detach removes any wildcard hash entry */ 976 #ifdef INET6 977 if (isafinet6) 978 in6_pcbdetach(inp); 979 else 980 #endif 981 in_pcbdetach(inp); 982 } 983 tcpstat.tcps_closed++; 984 return (NULL); 985 } 986 987 static __inline void 988 tcp_drain_oncpu(struct inpcbhead *head) 989 { 990 struct inpcb *inpb; 991 struct tcpcb *tcpb; 992 struct tseg_qent *te; 993 994 LIST_FOREACH(inpb, head, inp_list) { 995 if (inpb->inp_flags & INP_PLACEMARKER) 996 continue; 997 if ((tcpb = intotcpcb(inpb))) { 998 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) { 999 LIST_REMOVE(te, tqe_q); 1000 m_freem(te->tqe_m); 1001 FREE(te, M_TSEGQ); 1002 tcp_reass_qsize--; 1003 } 1004 } 1005 } 1006 } 1007 1008 #ifdef SMP 1009 struct netmsg_tcp_drain { 1010 struct lwkt_msg nm_lmsg; 1011 struct inpcbhead *nm_head; 1012 }; 1013 1014 static int 1015 tcp_drain_handler(lwkt_msg_t lmsg) 1016 { 1017 struct netmsg_tcp_drain *nm = (void *)lmsg; 1018 1019 tcp_drain_oncpu(nm->nm_head); 1020 lwkt_replymsg(lmsg, 0); 1021 return(EASYNC); 1022 } 1023 #endif 1024 1025 void 1026 tcp_drain(void) 1027 { 1028 #ifdef SMP 1029 int cpu; 1030 #endif 1031 1032 if (!do_tcpdrain) 1033 return; 1034 1035 /* 1036 * Walk the tcpbs, if existing, and flush the reassembly queue, 1037 * if there is one... 1038 * XXX: The "Net/3" implementation doesn't imply that the TCP 1039 * reassembly queue should be flushed, but in a situation 1040 * where we're really low on mbufs, this is potentially 1041 * useful. 1042 */ 1043 #ifdef SMP 1044 for (cpu = 0; cpu < ncpus2; cpu++) { 1045 struct netmsg_tcp_drain *msg; 1046 1047 if (cpu == mycpu->gd_cpuid) { 1048 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead); 1049 } else { 1050 msg = malloc(sizeof(struct netmsg_tcp_drain), 1051 M_LWKTMSG, M_NOWAIT); 1052 if (msg == NULL) 1053 continue; 1054 lwkt_initmsg(&msg->nm_lmsg, &netisr_afree_rport, 0, 1055 lwkt_cmd_func(tcp_drain_handler), 1056 lwkt_cmd_op_none); 1057 msg->nm_head = &tcbinfo[cpu].pcblisthead; 1058 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_lmsg); 1059 } 1060 } 1061 #else 1062 tcp_drain_oncpu(&tcbinfo[0].pcblisthead); 1063 #endif 1064 } 1065 1066 /* 1067 * Notify a tcp user of an asynchronous error; 1068 * store error as soft error, but wake up user 1069 * (for now, won't do anything until can select for soft error). 1070 * 1071 * Do not wake up user since there currently is no mechanism for 1072 * reporting soft errors (yet - a kqueue filter may be added). 1073 */ 1074 static void 1075 tcp_notify(struct inpcb *inp, int error) 1076 { 1077 struct tcpcb *tp = intotcpcb(inp); 1078 1079 /* 1080 * Ignore some errors if we are hooked up. 1081 * If connection hasn't completed, has retransmitted several times, 1082 * and receives a second error, give up now. This is better 1083 * than waiting a long time to establish a connection that 1084 * can never complete. 1085 */ 1086 if (tp->t_state == TCPS_ESTABLISHED && 1087 (error == EHOSTUNREACH || error == ENETUNREACH || 1088 error == EHOSTDOWN)) { 1089 return; 1090 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1091 tp->t_softerror) 1092 tcp_drop(tp, error); 1093 else 1094 tp->t_softerror = error; 1095 #if 0 1096 wakeup(&so->so_timeo); 1097 sorwakeup(so); 1098 sowwakeup(so); 1099 #endif 1100 } 1101 1102 static int 1103 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1104 { 1105 int error, i, n; 1106 struct inpcb *marker; 1107 struct inpcb *inp; 1108 inp_gen_t gencnt; 1109 globaldata_t gd; 1110 int origcpu, ccpu; 1111 1112 error = 0; 1113 n = 0; 1114 1115 /* 1116 * The process of preparing the TCB list is too time-consuming and 1117 * resource-intensive to repeat twice on every request. 1118 */ 1119 if (req->oldptr == NULL) { 1120 for (ccpu = 0; ccpu < ncpus; ++ccpu) { 1121 gd = globaldata_find(ccpu); 1122 n += tcbinfo[gd->gd_cpuid].ipi_count; 1123 } 1124 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb); 1125 return (0); 1126 } 1127 1128 if (req->newptr != NULL) 1129 return (EPERM); 1130 1131 marker = malloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1132 marker->inp_flags |= INP_PLACEMARKER; 1133 1134 /* 1135 * OK, now we're committed to doing something. Run the inpcb list 1136 * for each cpu in the system and construct the output. Use a 1137 * list placemarker to deal with list changes occuring during 1138 * copyout blockages (but otherwise depend on being on the correct 1139 * cpu to avoid races). 1140 */ 1141 origcpu = mycpu->gd_cpuid; 1142 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) { 1143 globaldata_t rgd; 1144 caddr_t inp_ppcb; 1145 struct xtcpcb xt; 1146 int cpu_id; 1147 1148 cpu_id = (origcpu + ccpu) % ncpus; 1149 if ((smp_active_mask & (1 << cpu_id)) == 0) 1150 continue; 1151 rgd = globaldata_find(cpu_id); 1152 lwkt_setcpu_self(rgd); 1153 1154 gencnt = tcbinfo[cpu_id].ipi_gencnt; 1155 n = tcbinfo[cpu_id].ipi_count; 1156 1157 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list); 1158 i = 0; 1159 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) { 1160 /* 1161 * process a snapshot of pcbs, ignoring placemarkers 1162 * and using our own to allow SYSCTL_OUT to block. 1163 */ 1164 LIST_REMOVE(marker, inp_list); 1165 LIST_INSERT_AFTER(inp, marker, inp_list); 1166 1167 if (inp->inp_flags & INP_PLACEMARKER) 1168 continue; 1169 if (inp->inp_gencnt > gencnt) 1170 continue; 1171 if (prison_xinpcb(req->td, inp)) 1172 continue; 1173 1174 xt.xt_len = sizeof xt; 1175 bcopy(inp, &xt.xt_inp, sizeof *inp); 1176 inp_ppcb = inp->inp_ppcb; 1177 if (inp_ppcb != NULL) 1178 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1179 else 1180 bzero(&xt.xt_tp, sizeof xt.xt_tp); 1181 if (inp->inp_socket) 1182 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1183 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0) 1184 break; 1185 ++i; 1186 } 1187 LIST_REMOVE(marker, inp_list); 1188 if (error == 0 && i < n) { 1189 bzero(&xt, sizeof xt); 1190 xt.xt_len = sizeof xt; 1191 while (i < n) { 1192 error = SYSCTL_OUT(req, &xt, sizeof xt); 1193 if (error) 1194 break; 1195 ++i; 1196 } 1197 } 1198 } 1199 1200 /* 1201 * Make sure we are on the same cpu we were on originally, since 1202 * higher level callers expect this. Also don't pollute caches with 1203 * migrated userland data by (eventually) returning to userland 1204 * on a different cpu. 1205 */ 1206 lwkt_setcpu_self(globaldata_find(origcpu)); 1207 free(marker, M_TEMP); 1208 return (error); 1209 } 1210 1211 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1212 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1213 1214 static int 1215 tcp_getcred(SYSCTL_HANDLER_ARGS) 1216 { 1217 struct sockaddr_in addrs[2]; 1218 struct inpcb *inp; 1219 int cpu; 1220 int error; 1221 1222 error = suser(req->td); 1223 if (error != 0) 1224 return (error); 1225 error = SYSCTL_IN(req, addrs, sizeof addrs); 1226 if (error != 0) 1227 return (error); 1228 crit_enter(); 1229 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1230 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1231 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1232 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1233 if (inp == NULL || inp->inp_socket == NULL) { 1234 error = ENOENT; 1235 goto out; 1236 } 1237 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1238 out: 1239 crit_exit(); 1240 return (error); 1241 } 1242 1243 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1244 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1245 1246 #ifdef INET6 1247 static int 1248 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1249 { 1250 struct sockaddr_in6 addrs[2]; 1251 struct inpcb *inp; 1252 int error; 1253 boolean_t mapped = FALSE; 1254 1255 error = suser(req->td); 1256 if (error != 0) 1257 return (error); 1258 error = SYSCTL_IN(req, addrs, sizeof addrs); 1259 if (error != 0) 1260 return (error); 1261 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1262 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1263 mapped = TRUE; 1264 else 1265 return (EINVAL); 1266 } 1267 crit_enter(); 1268 if (mapped) { 1269 inp = in_pcblookup_hash(&tcbinfo[0], 1270 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1271 addrs[1].sin6_port, 1272 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1273 addrs[0].sin6_port, 1274 0, NULL); 1275 } else { 1276 inp = in6_pcblookup_hash(&tcbinfo[0], 1277 &addrs[1].sin6_addr, addrs[1].sin6_port, 1278 &addrs[0].sin6_addr, addrs[0].sin6_port, 1279 0, NULL); 1280 } 1281 if (inp == NULL || inp->inp_socket == NULL) { 1282 error = ENOENT; 1283 goto out; 1284 } 1285 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1286 out: 1287 crit_exit(); 1288 return (error); 1289 } 1290 1291 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1292 0, 0, 1293 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1294 #endif 1295 1296 void 1297 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1298 { 1299 struct ip *ip = vip; 1300 struct tcphdr *th; 1301 struct in_addr faddr; 1302 struct inpcb *inp; 1303 struct tcpcb *tp; 1304 void (*notify)(struct inpcb *, int) = tcp_notify; 1305 tcp_seq icmpseq; 1306 int arg, cpu; 1307 1308 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) { 1309 return; 1310 } 1311 1312 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1313 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1314 return; 1315 1316 arg = inetctlerrmap[cmd]; 1317 if (cmd == PRC_QUENCH) { 1318 notify = tcp_quench; 1319 } else if (icmp_may_rst && 1320 (cmd == PRC_UNREACH_ADMIN_PROHIB || 1321 cmd == PRC_UNREACH_PORT || 1322 cmd == PRC_TIMXCEED_INTRANS) && 1323 ip != NULL) { 1324 notify = tcp_drop_syn_sent; 1325 } else if (cmd == PRC_MSGSIZE) { 1326 struct icmp *icmp = (struct icmp *) 1327 ((caddr_t)ip - offsetof(struct icmp, icmp_ip)); 1328 1329 arg = ntohs(icmp->icmp_nextmtu); 1330 notify = tcp_mtudisc; 1331 } else if (PRC_IS_REDIRECT(cmd)) { 1332 ip = NULL; 1333 notify = in_rtchange; 1334 } else if (cmd == PRC_HOSTDEAD) { 1335 ip = NULL; 1336 } 1337 1338 if (ip != NULL) { 1339 crit_enter(); 1340 th = (struct tcphdr *)((caddr_t)ip + 1341 (IP_VHL_HL(ip->ip_vhl) << 2)); 1342 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1343 ip->ip_src.s_addr, th->th_sport); 1344 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1345 ip->ip_src, th->th_sport, 0, NULL); 1346 if ((inp != NULL) && (inp->inp_socket != NULL)) { 1347 icmpseq = htonl(th->th_seq); 1348 tp = intotcpcb(inp); 1349 if (SEQ_GEQ(icmpseq, tp->snd_una) && 1350 SEQ_LT(icmpseq, tp->snd_max)) 1351 (*notify)(inp, arg); 1352 } else { 1353 struct in_conninfo inc; 1354 1355 inc.inc_fport = th->th_dport; 1356 inc.inc_lport = th->th_sport; 1357 inc.inc_faddr = faddr; 1358 inc.inc_laddr = ip->ip_src; 1359 #ifdef INET6 1360 inc.inc_isipv6 = 0; 1361 #endif 1362 syncache_unreach(&inc, th); 1363 } 1364 crit_exit(); 1365 } else { 1366 for (cpu = 0; cpu < ncpus2; cpu++) { 1367 in_pcbnotifyall(&tcbinfo[cpu].pcblisthead, faddr, arg, 1368 notify); 1369 } 1370 } 1371 } 1372 1373 #ifdef INET6 1374 void 1375 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1376 { 1377 struct tcphdr th; 1378 void (*notify) (struct inpcb *, int) = tcp_notify; 1379 struct ip6_hdr *ip6; 1380 struct mbuf *m; 1381 struct ip6ctlparam *ip6cp = NULL; 1382 const struct sockaddr_in6 *sa6_src = NULL; 1383 int off; 1384 struct tcp_portonly { 1385 u_int16_t th_sport; 1386 u_int16_t th_dport; 1387 } *thp; 1388 int arg; 1389 1390 if (sa->sa_family != AF_INET6 || 1391 sa->sa_len != sizeof(struct sockaddr_in6)) 1392 return; 1393 1394 arg = 0; 1395 if (cmd == PRC_QUENCH) 1396 notify = tcp_quench; 1397 else if (cmd == PRC_MSGSIZE) { 1398 struct ip6ctlparam *ip6cp = d; 1399 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6; 1400 1401 arg = ntohl(icmp6->icmp6_mtu); 1402 notify = tcp_mtudisc; 1403 } else if (!PRC_IS_REDIRECT(cmd) && 1404 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) { 1405 return; 1406 } 1407 1408 /* if the parameter is from icmp6, decode it. */ 1409 if (d != NULL) { 1410 ip6cp = (struct ip6ctlparam *)d; 1411 m = ip6cp->ip6c_m; 1412 ip6 = ip6cp->ip6c_ip6; 1413 off = ip6cp->ip6c_off; 1414 sa6_src = ip6cp->ip6c_src; 1415 } else { 1416 m = NULL; 1417 ip6 = NULL; 1418 off = 0; /* fool gcc */ 1419 sa6_src = &sa6_any; 1420 } 1421 1422 if (ip6 != NULL) { 1423 struct in_conninfo inc; 1424 /* 1425 * XXX: We assume that when IPV6 is non NULL, 1426 * M and OFF are valid. 1427 */ 1428 1429 /* check if we can safely examine src and dst ports */ 1430 if (m->m_pkthdr.len < off + sizeof *thp) 1431 return; 1432 1433 bzero(&th, sizeof th); 1434 m_copydata(m, off, sizeof *thp, (caddr_t)&th); 1435 1436 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport, 1437 (struct sockaddr *)ip6cp->ip6c_src, 1438 th.th_sport, cmd, arg, notify); 1439 1440 inc.inc_fport = th.th_dport; 1441 inc.inc_lport = th.th_sport; 1442 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1443 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1444 inc.inc_isipv6 = 1; 1445 syncache_unreach(&inc, &th); 1446 } else 1447 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0, 1448 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify); 1449 } 1450 #endif 1451 1452 /* 1453 * Following is where TCP initial sequence number generation occurs. 1454 * 1455 * There are two places where we must use initial sequence numbers: 1456 * 1. In SYN-ACK packets. 1457 * 2. In SYN packets. 1458 * 1459 * All ISNs for SYN-ACK packets are generated by the syncache. See 1460 * tcp_syncache.c for details. 1461 * 1462 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1463 * depends on this property. In addition, these ISNs should be 1464 * unguessable so as to prevent connection hijacking. To satisfy 1465 * the requirements of this situation, the algorithm outlined in 1466 * RFC 1948 is used to generate sequence numbers. 1467 * 1468 * Implementation details: 1469 * 1470 * Time is based off the system timer, and is corrected so that it 1471 * increases by one megabyte per second. This allows for proper 1472 * recycling on high speed LANs while still leaving over an hour 1473 * before rollover. 1474 * 1475 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1476 * between seeding of isn_secret. This is normally set to zero, 1477 * as reseeding should not be necessary. 1478 * 1479 */ 1480 1481 #define ISN_BYTES_PER_SECOND 1048576 1482 1483 u_char isn_secret[32]; 1484 int isn_last_reseed; 1485 MD5_CTX isn_ctx; 1486 1487 tcp_seq 1488 tcp_new_isn(struct tcpcb *tp) 1489 { 1490 u_int32_t md5_buffer[4]; 1491 tcp_seq new_isn; 1492 1493 /* Seed if this is the first use, reseed if requested. */ 1494 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1495 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1496 < (u_int)ticks))) { 1497 read_random_unlimited(&isn_secret, sizeof isn_secret); 1498 isn_last_reseed = ticks; 1499 } 1500 1501 /* Compute the md5 hash and return the ISN. */ 1502 MD5Init(&isn_ctx); 1503 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 1504 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 1505 #ifdef INET6 1506 if (tp->t_inpcb->inp_vflag & INP_IPV6) { 1507 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1508 sizeof(struct in6_addr)); 1509 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1510 sizeof(struct in6_addr)); 1511 } else 1512 #endif 1513 { 1514 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1515 sizeof(struct in_addr)); 1516 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1517 sizeof(struct in_addr)); 1518 } 1519 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1520 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1521 new_isn = (tcp_seq) md5_buffer[0]; 1522 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1523 return (new_isn); 1524 } 1525 1526 /* 1527 * When a source quench is received, close congestion window 1528 * to one segment. We will gradually open it again as we proceed. 1529 */ 1530 void 1531 tcp_quench(struct inpcb *inp, int errno) 1532 { 1533 struct tcpcb *tp = intotcpcb(inp); 1534 1535 if (tp != NULL) { 1536 tp->snd_cwnd = tp->t_maxseg; 1537 tp->snd_wacked = 0; 1538 } 1539 } 1540 1541 /* 1542 * When a specific ICMP unreachable message is received and the 1543 * connection state is SYN-SENT, drop the connection. This behavior 1544 * is controlled by the icmp_may_rst sysctl. 1545 */ 1546 void 1547 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1548 { 1549 struct tcpcb *tp = intotcpcb(inp); 1550 1551 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT)) 1552 tcp_drop(tp, errno); 1553 } 1554 1555 /* 1556 * When a `need fragmentation' ICMP is received, update our idea of the MSS 1557 * based on the new value in the route. Also nudge TCP to send something, 1558 * since we know the packet we just sent was dropped. 1559 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1560 */ 1561 void 1562 tcp_mtudisc(struct inpcb *inp, int mtu) 1563 { 1564 struct tcpcb *tp = intotcpcb(inp); 1565 struct rtentry *rt; 1566 struct socket *so = inp->inp_socket; 1567 int maxopd, mss; 1568 #ifdef INET6 1569 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0); 1570 #else 1571 const boolean_t isipv6 = FALSE; 1572 #endif 1573 1574 if (tp == NULL) 1575 return; 1576 1577 /* 1578 * If no MTU is provided in the ICMP message, use the 1579 * next lower likely value, as specified in RFC 1191. 1580 */ 1581 if (mtu == 0) { 1582 int oldmtu; 1583 1584 oldmtu = tp->t_maxopd + 1585 (isipv6 ? 1586 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1587 sizeof(struct tcpiphdr)); 1588 mtu = ip_next_mtu(oldmtu, 0); 1589 } 1590 1591 if (isipv6) 1592 rt = tcp_rtlookup6(&inp->inp_inc); 1593 else 1594 rt = tcp_rtlookup(&inp->inp_inc); 1595 if (rt != NULL) { 1596 struct rmxp_tao *taop = rmx_taop(rt->rt_rmx); 1597 1598 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu) 1599 mtu = rt->rt_rmx.rmx_mtu; 1600 1601 maxopd = mtu - 1602 (isipv6 ? 1603 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1604 sizeof(struct tcpiphdr)); 1605 1606 /* 1607 * XXX - The following conditional probably violates the TCP 1608 * spec. The problem is that, since we don't know the 1609 * other end's MSS, we are supposed to use a conservative 1610 * default. But, if we do that, then MTU discovery will 1611 * never actually take place, because the conservative 1612 * default is much less than the MTUs typically seen 1613 * on the Internet today. For the moment, we'll sweep 1614 * this under the carpet. 1615 * 1616 * The conservative default might not actually be a problem 1617 * if the only case this occurs is when sending an initial 1618 * SYN with options and data to a host we've never talked 1619 * to before. Then, they will reply with an MSS value which 1620 * will get recorded and the new parameters should get 1621 * recomputed. For Further Study. 1622 */ 1623 if (taop->tao_mssopt != 0 && taop->tao_mssopt < maxopd) 1624 maxopd = taop->tao_mssopt; 1625 } else 1626 maxopd = mtu - 1627 (isipv6 ? 1628 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1629 sizeof(struct tcpiphdr)); 1630 1631 if (tp->t_maxopd <= maxopd) 1632 return; 1633 tp->t_maxopd = maxopd; 1634 1635 mss = maxopd; 1636 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) == 1637 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1638 mss -= TCPOLEN_TSTAMP_APPA; 1639 1640 if ((tp->t_flags & (TF_REQ_CC | TF_RCVD_CC | TF_NOOPT)) == 1641 (TF_REQ_CC | TF_RCVD_CC)) 1642 mss -= TCPOLEN_CC_APPA; 1643 1644 /* round down to multiple of MCLBYTES */ 1645 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */ 1646 if (mss > MCLBYTES) 1647 mss &= ~(MCLBYTES - 1); 1648 #else 1649 if (mss > MCLBYTES) 1650 mss = (mss / MCLBYTES) * MCLBYTES; 1651 #endif 1652 1653 if (so->so_snd.sb_hiwat < mss) 1654 mss = so->so_snd.sb_hiwat; 1655 1656 tp->t_maxseg = mss; 1657 tp->t_rtttime = 0; 1658 tp->snd_nxt = tp->snd_una; 1659 tcp_output(tp); 1660 tcpstat.tcps_mturesent++; 1661 } 1662 1663 /* 1664 * Look-up the routing entry to the peer of this inpcb. If no route 1665 * is found and it cannot be allocated the return NULL. This routine 1666 * is called by TCP routines that access the rmx structure and by tcp_mss 1667 * to get the interface MTU. 1668 */ 1669 struct rtentry * 1670 tcp_rtlookup(struct in_conninfo *inc) 1671 { 1672 struct route *ro = &inc->inc_route; 1673 1674 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) { 1675 /* No route yet, so try to acquire one */ 1676 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1677 /* 1678 * unused portions of the structure MUST be zero'd 1679 * out because rtalloc() treats it as opaque data 1680 */ 1681 bzero(&ro->ro_dst, sizeof(struct sockaddr_in)); 1682 ro->ro_dst.sa_family = AF_INET; 1683 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1684 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1685 inc->inc_faddr; 1686 rtalloc(ro); 1687 } 1688 } 1689 return (ro->ro_rt); 1690 } 1691 1692 #ifdef INET6 1693 struct rtentry * 1694 tcp_rtlookup6(struct in_conninfo *inc) 1695 { 1696 struct route_in6 *ro6 = &inc->inc6_route; 1697 1698 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) { 1699 /* No route yet, so try to acquire one */ 1700 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1701 /* 1702 * unused portions of the structure MUST be zero'd 1703 * out because rtalloc() treats it as opaque data 1704 */ 1705 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6)); 1706 ro6->ro_dst.sin6_family = AF_INET6; 1707 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1708 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1709 rtalloc((struct route *)ro6); 1710 } 1711 } 1712 return (ro6->ro_rt); 1713 } 1714 #endif 1715 1716 #ifdef IPSEC 1717 /* compute ESP/AH header size for TCP, including outer IP header. */ 1718 size_t 1719 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1720 { 1721 struct inpcb *inp; 1722 struct mbuf *m; 1723 size_t hdrsiz; 1724 struct ip *ip; 1725 struct tcphdr *th; 1726 1727 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1728 return (0); 1729 MGETHDR(m, MB_DONTWAIT, MT_DATA); 1730 if (!m) 1731 return (0); 1732 1733 #ifdef INET6 1734 if (inp->inp_vflag & INP_IPV6) { 1735 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 1736 1737 th = (struct tcphdr *)(ip6 + 1); 1738 m->m_pkthdr.len = m->m_len = 1739 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1740 tcp_fillheaders(tp, ip6, th); 1741 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1742 } else 1743 #endif 1744 { 1745 ip = mtod(m, struct ip *); 1746 th = (struct tcphdr *)(ip + 1); 1747 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1748 tcp_fillheaders(tp, ip, th); 1749 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1750 } 1751 1752 m_free(m); 1753 return (hdrsiz); 1754 } 1755 #endif 1756 1757 /* 1758 * Return a pointer to the cached information about the remote host. 1759 * The cached information is stored in the protocol specific part of 1760 * the route metrics. 1761 */ 1762 struct rmxp_tao * 1763 tcp_gettaocache(struct in_conninfo *inc) 1764 { 1765 struct rtentry *rt; 1766 1767 #ifdef INET6 1768 if (inc->inc_isipv6) 1769 rt = tcp_rtlookup6(inc); 1770 else 1771 #endif 1772 rt = tcp_rtlookup(inc); 1773 1774 /* Make sure this is a host route and is up. */ 1775 if (rt == NULL || 1776 (rt->rt_flags & (RTF_UP | RTF_HOST)) != (RTF_UP | RTF_HOST)) 1777 return (NULL); 1778 1779 return (rmx_taop(rt->rt_rmx)); 1780 } 1781 1782 /* 1783 * Clear all the TAO cache entries, called from tcp_init. 1784 * 1785 * XXX 1786 * This routine is just an empty one, because we assume that the routing 1787 * routing tables are initialized at the same time when TCP, so there is 1788 * nothing in the cache left over. 1789 */ 1790 static void 1791 tcp_cleartaocache(void) 1792 { 1793 } 1794 1795 /* 1796 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1797 * 1798 * This code attempts to calculate the bandwidth-delay product as a 1799 * means of determining the optimal window size to maximize bandwidth, 1800 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1801 * routers. This code also does a fairly good job keeping RTTs in check 1802 * across slow links like modems. We implement an algorithm which is very 1803 * similar (but not meant to be) TCP/Vegas. The code operates on the 1804 * transmitter side of a TCP connection and so only effects the transmit 1805 * side of the connection. 1806 * 1807 * BACKGROUND: TCP makes no provision for the management of buffer space 1808 * at the end points or at the intermediate routers and switches. A TCP 1809 * stream, whether using NewReno or not, will eventually buffer as 1810 * many packets as it is able and the only reason this typically works is 1811 * due to the fairly small default buffers made available for a connection 1812 * (typicaly 16K or 32K). As machines use larger windows and/or window 1813 * scaling it is now fairly easy for even a single TCP connection to blow-out 1814 * all available buffer space not only on the local interface, but on 1815 * intermediate routers and switches as well. NewReno makes a misguided 1816 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1817 * then backing off, then steadily increasing the window again until another 1818 * failure occurs, ad-infinitum. This results in terrible oscillation that 1819 * is only made worse as network loads increase and the idea of intentionally 1820 * blowing out network buffers is, frankly, a terrible way to manage network 1821 * resources. 1822 * 1823 * It is far better to limit the transmit window prior to the failure 1824 * condition being achieved. There are two general ways to do this: First 1825 * you can 'scan' through different transmit window sizes and locate the 1826 * point where the RTT stops increasing, indicating that you have filled the 1827 * pipe, then scan backwards until you note that RTT stops decreasing, then 1828 * repeat ad-infinitum. This method works in principle but has severe 1829 * implementation issues due to RTT variances, timer granularity, and 1830 * instability in the algorithm which can lead to many false positives and 1831 * create oscillations as well as interact badly with other TCP streams 1832 * implementing the same algorithm. 1833 * 1834 * The second method is to limit the window to the bandwidth delay product 1835 * of the link. This is the method we implement. RTT variances and our 1836 * own manipulation of the congestion window, bwnd, can potentially 1837 * destabilize the algorithm. For this reason we have to stabilize the 1838 * elements used to calculate the window. We do this by using the minimum 1839 * observed RTT, the long term average of the observed bandwidth, and 1840 * by adding two segments worth of slop. It isn't perfect but it is able 1841 * to react to changing conditions and gives us a very stable basis on 1842 * which to extend the algorithm. 1843 */ 1844 void 1845 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1846 { 1847 u_long bw; 1848 u_long bwnd; 1849 int save_ticks; 1850 int delta_ticks; 1851 1852 /* 1853 * If inflight_enable is disabled in the middle of a tcp connection, 1854 * make sure snd_bwnd is effectively disabled. 1855 */ 1856 if (!tcp_inflight_enable) { 1857 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1858 tp->snd_bandwidth = 0; 1859 return; 1860 } 1861 1862 /* 1863 * Validate the delta time. If a connection is new or has been idle 1864 * a long time we have to reset the bandwidth calculator. 1865 */ 1866 save_ticks = ticks; 1867 delta_ticks = save_ticks - tp->t_bw_rtttime; 1868 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) { 1869 tp->t_bw_rtttime = ticks; 1870 tp->t_bw_rtseq = ack_seq; 1871 if (tp->snd_bandwidth == 0) 1872 tp->snd_bandwidth = tcp_inflight_min; 1873 return; 1874 } 1875 if (delta_ticks == 0) 1876 return; 1877 1878 /* 1879 * Sanity check, plus ignore pure window update acks. 1880 */ 1881 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0) 1882 return; 1883 1884 /* 1885 * Figure out the bandwidth. Due to the tick granularity this 1886 * is a very rough number and it MUST be averaged over a fairly 1887 * long period of time. XXX we need to take into account a link 1888 * that is not using all available bandwidth, but for now our 1889 * slop will ramp us up if this case occurs and the bandwidth later 1890 * increases. 1891 */ 1892 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks; 1893 tp->t_bw_rtttime = save_ticks; 1894 tp->t_bw_rtseq = ack_seq; 1895 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1896 1897 tp->snd_bandwidth = bw; 1898 1899 /* 1900 * Calculate the semi-static bandwidth delay product, plus two maximal 1901 * segments. The additional slop puts us squarely in the sweet 1902 * spot and also handles the bandwidth run-up case. Without the 1903 * slop we could be locking ourselves into a lower bandwidth. 1904 * 1905 * Situations Handled: 1906 * (1) Prevents over-queueing of packets on LANs, especially on 1907 * high speed LANs, allowing larger TCP buffers to be 1908 * specified, and also does a good job preventing 1909 * over-queueing of packets over choke points like modems 1910 * (at least for the transmit side). 1911 * 1912 * (2) Is able to handle changing network loads (bandwidth 1913 * drops so bwnd drops, bandwidth increases so bwnd 1914 * increases). 1915 * 1916 * (3) Theoretically should stabilize in the face of multiple 1917 * connections implementing the same algorithm (this may need 1918 * a little work). 1919 * 1920 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1921 * be adjusted with a sysctl but typically only needs to be on 1922 * very slow connections. A value no smaller then 5 should 1923 * be used, but only reduce this default if you have no other 1924 * choice. 1925 */ 1926 1927 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1928 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + 1929 tcp_inflight_stab * (int)tp->t_maxseg / 10; 1930 #undef USERTT 1931 1932 if (tcp_inflight_debug > 0) { 1933 static int ltime; 1934 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1935 ltime = ticks; 1936 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1937 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd); 1938 } 1939 } 1940 if ((long)bwnd < tcp_inflight_min) 1941 bwnd = tcp_inflight_min; 1942 if (bwnd > tcp_inflight_max) 1943 bwnd = tcp_inflight_max; 1944 if ((long)bwnd < tp->t_maxseg * 2) 1945 bwnd = tp->t_maxseg * 2; 1946 tp->snd_bwnd = bwnd; 1947 } 1948