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 1.45 2005/03/06 05:09:25 hsu 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> 110 111 #include <vm/vm_zone.h> 112 113 #include <net/route.h> 114 #include <net/if.h> 115 #include <net/netisr.h> 116 117 #define _IP_VHL 118 #include <netinet/in.h> 119 #include <netinet/in_systm.h> 120 #include <netinet/ip.h> 121 #include <netinet/ip6.h> 122 #include <netinet/in_pcb.h> 123 #include <netinet6/in6_pcb.h> 124 #include <netinet/in_var.h> 125 #include <netinet/ip_var.h> 126 #include <netinet6/ip6_var.h> 127 #include <netinet/ip_icmp.h> 128 #ifdef INET6 129 #include <netinet/icmp6.h> 130 #endif 131 #include <netinet/tcp.h> 132 #include <netinet/tcp_fsm.h> 133 #include <netinet/tcp_seq.h> 134 #include <netinet/tcp_timer.h> 135 #include <netinet/tcp_var.h> 136 #include <netinet6/tcp6_var.h> 137 #include <netinet/tcpip.h> 138 #ifdef TCPDEBUG 139 #include <netinet/tcp_debug.h> 140 #endif 141 #include <netinet6/ip6protosw.h> 142 143 #ifdef IPSEC 144 #include <netinet6/ipsec.h> 145 #ifdef INET6 146 #include <netinet6/ipsec6.h> 147 #endif 148 #endif 149 150 #ifdef FAST_IPSEC 151 #include <netproto/ipsec/ipsec.h> 152 #ifdef INET6 153 #include <netproto/ipsec/ipsec6.h> 154 #endif 155 #define IPSEC 156 #endif 157 158 #include <sys/md5.h> 159 160 #include <sys/msgport2.h> 161 162 #include <machine/smp.h> 163 164 struct inpcbinfo tcbinfo[MAXCPU]; 165 struct tcpcbackqhead tcpcbackq[MAXCPU]; 166 167 int tcp_mssdflt = TCP_MSS; 168 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 169 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size"); 170 171 #ifdef INET6 172 int tcp_v6mssdflt = TCP6_MSS; 173 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW, 174 &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6"); 175 #endif 176 177 #if 0 178 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 179 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 180 &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time"); 181 #endif 182 183 int tcp_do_rfc1323 = 1; 184 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 185 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions"); 186 187 int tcp_do_rfc1644 = 0; 188 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 189 &tcp_do_rfc1644, 0, "Enable rfc1644 (TTCP) extensions"); 190 191 static int tcp_tcbhashsize = 0; 192 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 193 &tcp_tcbhashsize, 0, "Size of TCP control block hashtable"); 194 195 static int do_tcpdrain = 1; 196 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 197 "Enable tcp_drain routine for extra help when low on mbufs"); 198 199 /* XXX JH */ 200 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 201 &tcbinfo[0].ipi_count, 0, "Number of active PCBs"); 202 203 static int icmp_may_rst = 1; 204 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 205 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 206 207 static int tcp_isn_reseed_interval = 0; 208 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 209 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 210 211 /* 212 * TCP bandwidth limiting sysctls. Note that the default lower bound of 213 * 1024 exists only for debugging. A good production default would be 214 * something like 6100. 215 */ 216 static int tcp_inflight_enable = 0; 217 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW, 218 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 219 220 static int tcp_inflight_debug = 0; 221 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW, 222 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 223 224 static int tcp_inflight_min = 6144; 225 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW, 226 &tcp_inflight_min, 0, "Lower bound for TCP inflight window"); 227 228 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 229 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW, 230 &tcp_inflight_max, 0, "Upper bound for TCP inflight window"); 231 232 static int tcp_inflight_stab = 20; 233 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW, 234 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 2 packets)"); 235 236 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives"); 237 static struct malloc_pipe tcptemp_mpipe; 238 239 static void tcp_willblock(void); 240 static void tcp_cleartaocache (void); 241 static void tcp_notify (struct inpcb *, int); 242 243 struct tcp_stats tcpstats_ary[MAXCPU]; 244 #ifdef SMP 245 static int 246 sysctl_tcpstats(SYSCTL_HANDLER_ARGS) 247 { 248 int cpu, error = 0; 249 250 for (cpu = 0; cpu < ncpus; ++cpu) { 251 if ((error = SYSCTL_OUT(req, &tcpstats_ary[cpu], 252 sizeof(struct tcp_stats)))) 253 break; 254 if ((error = SYSCTL_IN(req, &tcpstats_ary[cpu], 255 sizeof(struct tcp_stats)))) 256 break; 257 } 258 259 return (error); 260 } 261 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 262 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics"); 263 #else 264 SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW, 265 &tcpstat, tcp_stats, "TCP statistics"); 266 #endif 267 268 /* 269 * Target size of TCP PCB hash tables. Must be a power of two. 270 * 271 * Note that this can be overridden by the kernel environment 272 * variable net.inet.tcp.tcbhashsize 273 */ 274 #ifndef TCBHASHSIZE 275 #define TCBHASHSIZE 512 276 #endif 277 278 /* 279 * This is the actual shape of what we allocate using the zone 280 * allocator. Doing it this way allows us to protect both structures 281 * using the same generation count, and also eliminates the overhead 282 * of allocating tcpcbs separately. By hiding the structure here, 283 * we avoid changing most of the rest of the code (although it needs 284 * to be changed, eventually, for greater efficiency). 285 */ 286 #define ALIGNMENT 32 287 #define ALIGNM1 (ALIGNMENT - 1) 288 struct inp_tp { 289 union { 290 struct inpcb inp; 291 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 292 } inp_tp_u; 293 struct tcpcb tcb; 294 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl; 295 struct callout inp_tp_delack; 296 }; 297 #undef ALIGNMENT 298 #undef ALIGNM1 299 300 /* 301 * Tcp initialization 302 */ 303 void 304 tcp_init() 305 { 306 struct inpcbporthead *porthashbase; 307 u_long porthashmask; 308 struct vm_zone *ipi_zone; 309 int hashsize = TCBHASHSIZE; 310 int cpu; 311 312 /* 313 * note: tcptemp is used for keepalives, and it is ok for an 314 * allocation to fail so do not specify MPF_INT. 315 */ 316 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp), 317 25, -1, 0, NULL); 318 319 tcp_ccgen = 1; 320 tcp_cleartaocache(); 321 322 tcp_delacktime = TCPTV_DELACK; 323 tcp_keepinit = TCPTV_KEEP_INIT; 324 tcp_keepidle = TCPTV_KEEP_IDLE; 325 tcp_keepintvl = TCPTV_KEEPINTVL; 326 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 327 tcp_msl = TCPTV_MSL; 328 tcp_rexmit_min = TCPTV_MIN; 329 tcp_rexmit_slop = TCPTV_CPU_VAR; 330 331 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 332 if (!powerof2(hashsize)) { 333 printf("WARNING: TCB hash size not a power of 2\n"); 334 hashsize = 512; /* safe default */ 335 } 336 tcp_tcbhashsize = hashsize; 337 porthashbase = hashinit(hashsize, M_PCB, &porthashmask); 338 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 339 ZONE_INTERRUPT, 0); 340 341 for (cpu = 0; cpu < ncpus2; cpu++) { 342 in_pcbinfo_init(&tcbinfo[cpu]); 343 tcbinfo[cpu].cpu = cpu; 344 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB, 345 &tcbinfo[cpu].hashmask); 346 tcbinfo[cpu].porthashbase = porthashbase; 347 tcbinfo[cpu].porthashmask = porthashmask; 348 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB, 349 &tcbinfo[cpu].wildcardhashmask); 350 tcbinfo[cpu].ipi_zone = ipi_zone; 351 TAILQ_INIT(&tcpcbackq[cpu]); 352 } 353 354 tcp_reass_maxseg = nmbclusters / 16; 355 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg); 356 357 #ifdef INET6 358 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 359 #else 360 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 361 #endif 362 if (max_protohdr < TCP_MINPROTOHDR) 363 max_protohdr = TCP_MINPROTOHDR; 364 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 365 panic("tcp_init"); 366 #undef TCP_MINPROTOHDR 367 368 /* 369 * Initialize TCP statistics. 370 * 371 * It is layed out as an array which is has one element for UP, 372 * and SMP_MAXCPU elements for SMP. This allows us to retain 373 * the access mechanism from userland for both UP and SMP. 374 */ 375 #ifdef SMP 376 for (cpu = 0; cpu < ncpus; ++cpu) { 377 bzero(&tcpstats_ary[cpu], sizeof(struct tcp_stats)); 378 } 379 #else 380 bzero(&tcpstat, sizeof(struct tcp_stats)); 381 #endif 382 383 syncache_init(); 384 tcp_sack_init(); 385 tcp_thread_init(); 386 } 387 388 void 389 tcpmsg_service_loop(void *dummy) 390 { 391 struct netmsg *msg; 392 393 while ((msg = lwkt_waitport(&curthread->td_msgport, NULL))) { 394 do { 395 msg->nm_lmsg.ms_cmd.cm_func(&msg->nm_lmsg); 396 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL); 397 tcp_willblock(); 398 } 399 } 400 401 static void 402 tcp_willblock(void) 403 { 404 struct tcpcb *tp; 405 int cpu = mycpu->gd_cpuid; 406 407 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) { 408 KKASSERT(tp->t_flags & TF_ONOUTPUTQ); 409 tp->t_flags &= ~TF_ONOUTPUTQ; 410 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq); 411 tcp_output(tp); 412 } 413 } 414 415 416 /* 417 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 418 * tcp_template used to store this data in mbufs, but we now recopy it out 419 * of the tcpcb each time to conserve mbufs. 420 */ 421 void 422 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr) 423 { 424 struct inpcb *inp = tp->t_inpcb; 425 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 426 427 #ifdef INET6 428 if (inp->inp_vflag & INP_IPV6) { 429 struct ip6_hdr *ip6; 430 431 ip6 = (struct ip6_hdr *)ip_ptr; 432 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 433 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 434 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 435 (IPV6_VERSION & IPV6_VERSION_MASK); 436 ip6->ip6_nxt = IPPROTO_TCP; 437 ip6->ip6_plen = sizeof(struct tcphdr); 438 ip6->ip6_src = inp->in6p_laddr; 439 ip6->ip6_dst = inp->in6p_faddr; 440 tcp_hdr->th_sum = 0; 441 } else 442 #endif 443 { 444 struct ip *ip = (struct ip *) ip_ptr; 445 446 ip->ip_vhl = IP_VHL_BORING; 447 ip->ip_tos = 0; 448 ip->ip_len = 0; 449 ip->ip_id = 0; 450 ip->ip_off = 0; 451 ip->ip_ttl = 0; 452 ip->ip_sum = 0; 453 ip->ip_p = IPPROTO_TCP; 454 ip->ip_src = inp->inp_laddr; 455 ip->ip_dst = inp->inp_faddr; 456 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, 457 ip->ip_dst.s_addr, 458 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 459 } 460 461 tcp_hdr->th_sport = inp->inp_lport; 462 tcp_hdr->th_dport = inp->inp_fport; 463 tcp_hdr->th_seq = 0; 464 tcp_hdr->th_ack = 0; 465 tcp_hdr->th_x2 = 0; 466 tcp_hdr->th_off = 5; 467 tcp_hdr->th_flags = 0; 468 tcp_hdr->th_win = 0; 469 tcp_hdr->th_urp = 0; 470 } 471 472 /* 473 * Create template to be used to send tcp packets on a connection. 474 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 475 * use for this function is in keepalives, which use tcp_respond. 476 */ 477 struct tcptemp * 478 tcp_maketemplate(struct tcpcb *tp) 479 { 480 struct tcptemp *tmp; 481 482 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL) 483 return (NULL); 484 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t); 485 return (tmp); 486 } 487 488 void 489 tcp_freetemplate(struct tcptemp *tmp) 490 { 491 mpipe_free(&tcptemp_mpipe, tmp); 492 } 493 494 /* 495 * Send a single message to the TCP at address specified by 496 * the given TCP/IP header. If m == NULL, then we make a copy 497 * of the tcpiphdr at ti and send directly to the addressed host. 498 * This is used to force keep alive messages out using the TCP 499 * template for a connection. If flags are given then we send 500 * a message back to the TCP which originated the * segment ti, 501 * and discard the mbuf containing it and any other attached mbufs. 502 * 503 * In any case the ack and sequence number of the transmitted 504 * segment are as specified by the parameters. 505 * 506 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 507 */ 508 void 509 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 510 tcp_seq ack, tcp_seq seq, int flags) 511 { 512 int tlen; 513 int win = 0; 514 struct route *ro = NULL; 515 struct route sro; 516 struct ip *ip = ipgen; 517 struct tcphdr *nth; 518 int ipflags = 0; 519 struct route_in6 *ro6 = NULL; 520 struct route_in6 sro6; 521 struct ip6_hdr *ip6 = ipgen; 522 #ifdef INET6 523 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6); 524 #else 525 const boolean_t isipv6 = FALSE; 526 #endif 527 528 if (tp != NULL) { 529 if (!(flags & TH_RST)) { 530 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 531 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 532 win = (long)TCP_MAXWIN << tp->rcv_scale; 533 } 534 if (isipv6) 535 ro6 = &tp->t_inpcb->in6p_route; 536 else 537 ro = &tp->t_inpcb->inp_route; 538 } else { 539 if (isipv6) { 540 ro6 = &sro6; 541 bzero(ro6, sizeof *ro6); 542 } else { 543 ro = &sro; 544 bzero(ro, sizeof *ro); 545 } 546 } 547 if (m == NULL) { 548 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 549 if (m == NULL) 550 return; 551 tlen = 0; 552 m->m_data += max_linkhdr; 553 if (isipv6) { 554 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr)); 555 ip6 = mtod(m, struct ip6_hdr *); 556 nth = (struct tcphdr *)(ip6 + 1); 557 } else { 558 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); 559 ip = mtod(m, struct ip *); 560 nth = (struct tcphdr *)(ip + 1); 561 } 562 bcopy(th, nth, sizeof(struct tcphdr)); 563 flags = TH_ACK; 564 } else { 565 m_freem(m->m_next); 566 m->m_next = NULL; 567 m->m_data = (caddr_t)ipgen; 568 /* m_len is set later */ 569 tlen = 0; 570 #define xchg(a, b, type) { type t; t = a; a = b; b = t; } 571 if (isipv6) { 572 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 573 nth = (struct tcphdr *)(ip6 + 1); 574 } else { 575 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 576 nth = (struct tcphdr *)(ip + 1); 577 } 578 if (th != nth) { 579 /* 580 * this is usually a case when an extension header 581 * exists between the IPv6 header and the 582 * TCP header. 583 */ 584 nth->th_sport = th->th_sport; 585 nth->th_dport = th->th_dport; 586 } 587 xchg(nth->th_dport, nth->th_sport, n_short); 588 #undef xchg 589 } 590 if (isipv6) { 591 ip6->ip6_flow = 0; 592 ip6->ip6_vfc = IPV6_VERSION; 593 ip6->ip6_nxt = IPPROTO_TCP; 594 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen)); 595 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 596 } else { 597 tlen += sizeof(struct tcpiphdr); 598 ip->ip_len = tlen; 599 ip->ip_ttl = ip_defttl; 600 } 601 m->m_len = tlen; 602 m->m_pkthdr.len = tlen; 603 m->m_pkthdr.rcvif = (struct ifnet *) NULL; 604 nth->th_seq = htonl(seq); 605 nth->th_ack = htonl(ack); 606 nth->th_x2 = 0; 607 nth->th_off = sizeof(struct tcphdr) >> 2; 608 nth->th_flags = flags; 609 if (tp != NULL) 610 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 611 else 612 nth->th_win = htons((u_short)win); 613 nth->th_urp = 0; 614 if (isipv6) { 615 nth->th_sum = 0; 616 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 617 sizeof(struct ip6_hdr), 618 tlen - sizeof(struct ip6_hdr)); 619 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 620 (ro6 && ro6->ro_rt) ? 621 ro6->ro_rt->rt_ifp : NULL); 622 } else { 623 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 624 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 625 m->m_pkthdr.csum_flags = CSUM_TCP; 626 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 627 } 628 #ifdef TCPDEBUG 629 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 630 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 631 #endif 632 if (isipv6) { 633 ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 634 tp ? tp->t_inpcb : NULL); 635 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) { 636 RTFREE(ro6->ro_rt); 637 ro6->ro_rt = NULL; 638 } 639 } else { 640 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 641 if ((ro == &sro) && (ro->ro_rt != NULL)) { 642 RTFREE(ro->ro_rt); 643 ro->ro_rt = NULL; 644 } 645 } 646 } 647 648 /* 649 * Create a new TCP control block, making an 650 * empty reassembly queue and hooking it to the argument 651 * protocol control block. The `inp' parameter must have 652 * come from the zone allocator set up in tcp_init(). 653 */ 654 struct tcpcb * 655 tcp_newtcpcb(struct inpcb *inp) 656 { 657 struct inp_tp *it; 658 struct tcpcb *tp; 659 #ifdef INET6 660 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 661 #else 662 const boolean_t isipv6 = FALSE; 663 #endif 664 665 it = (struct inp_tp *)inp; 666 tp = &it->tcb; 667 bzero(tp, sizeof(struct tcpcb)); 668 LIST_INIT(&tp->t_segq); 669 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt; 670 671 /* Set up our timeouts. */ 672 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt); 673 callout_init(tp->tt_persist = &it->inp_tp_persist); 674 callout_init(tp->tt_keep = &it->inp_tp_keep); 675 callout_init(tp->tt_2msl = &it->inp_tp_2msl); 676 callout_init(tp->tt_delack = &it->inp_tp_delack); 677 678 if (tcp_do_rfc1323) 679 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP); 680 if (tcp_do_rfc1644) 681 tp->t_flags |= TF_REQ_CC; 682 tp->t_inpcb = inp; /* XXX */ 683 tp->t_state = TCPS_CLOSED; 684 /* 685 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 686 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 687 * reasonable initial retransmit time. 688 */ 689 tp->t_srtt = TCPTV_SRTTBASE; 690 tp->t_rttvar = 691 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 692 tp->t_rttmin = tcp_rexmit_min; 693 tp->t_rxtcur = TCPTV_RTOBASE; 694 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 695 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 696 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 697 tp->t_rcvtime = ticks; 698 /* 699 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 700 * because the socket may be bound to an IPv6 wildcard address, 701 * which may match an IPv4-mapped IPv6 address. 702 */ 703 inp->inp_ip_ttl = ip_defttl; 704 inp->inp_ppcb = tp; 705 tcp_sack_tcpcb_init(tp); 706 return (tp); /* XXX */ 707 } 708 709 /* 710 * Drop a TCP connection, reporting the specified error. 711 * If connection is synchronized, then send a RST to peer. 712 */ 713 struct tcpcb * 714 tcp_drop(struct tcpcb *tp, int errno) 715 { 716 struct socket *so = tp->t_inpcb->inp_socket; 717 718 if (TCPS_HAVERCVDSYN(tp->t_state)) { 719 tp->t_state = TCPS_CLOSED; 720 tcp_output(tp); 721 tcpstat.tcps_drops++; 722 } else 723 tcpstat.tcps_conndrops++; 724 if (errno == ETIMEDOUT && tp->t_softerror) 725 errno = tp->t_softerror; 726 so->so_error = errno; 727 return (tcp_close(tp)); 728 } 729 730 #ifdef SMP 731 732 struct netmsg_remwildcard { 733 struct lwkt_msg nm_lmsg; 734 struct inpcb *nm_inp; 735 struct inpcbinfo *nm_pcbinfo; 736 #if defined(INET6) 737 int nm_isinet6; 738 #else 739 int nm_unused01; 740 #endif 741 }; 742 743 /* 744 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the 745 * inp can be detached. We do this by cycling through the cpus, ending up 746 * on the cpu controlling the inp last and then doing the disconnect. 747 */ 748 static int 749 in_pcbremwildcardhash_handler(struct lwkt_msg *msg0) 750 { 751 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0; 752 int cpu; 753 754 cpu = msg->nm_pcbinfo->cpu; 755 756 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) { 757 /* note: detach removes any wildcard hash entry */ 758 #ifdef INET6 759 if (msg->nm_isinet6) 760 in6_pcbdetach(msg->nm_inp); 761 else 762 #endif 763 in_pcbdetach(msg->nm_inp); 764 lwkt_replymsg(&msg->nm_lmsg, 0); 765 } else { 766 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo); 767 cpu = (cpu + 1) % ncpus2; 768 msg->nm_pcbinfo = &tcbinfo[cpu]; 769 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_lmsg); 770 } 771 return (EASYNC); 772 } 773 774 #endif 775 776 /* 777 * Close a TCP control block: 778 * discard all space held by the tcp 779 * discard internet protocol block 780 * wake up any sleepers 781 */ 782 struct tcpcb * 783 tcp_close(struct tcpcb *tp) 784 { 785 struct tseg_qent *q; 786 struct inpcb *inp = tp->t_inpcb; 787 struct socket *so = inp->inp_socket; 788 struct rtentry *rt; 789 boolean_t dosavessthresh; 790 #ifdef SMP 791 int cpu; 792 #endif 793 #ifdef INET6 794 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 795 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0); 796 #else 797 const boolean_t isipv6 = FALSE; 798 #endif 799 800 /* 801 * The tp is not instantly destroyed in the wildcard case. Setting 802 * the state to TCPS_TERMINATING will prevent the TCP stack from 803 * messing with it, though it should be noted that this change may 804 * not take effect on other cpus until we have chained the wildcard 805 * hash removal. 806 * 807 * XXX we currently depend on the BGL to synchronize the tp->t_state 808 * update and prevent other tcp protocol threads from accepting new 809 * connections on the listen socket we might be trying to close down. 810 */ 811 KKASSERT(tp->t_state != TCPS_TERMINATING); 812 tp->t_state = TCPS_TERMINATING; 813 814 /* 815 * Make sure that all of our timers are stopped before we 816 * delete the PCB. 817 */ 818 callout_stop(tp->tt_rexmt); 819 callout_stop(tp->tt_persist); 820 callout_stop(tp->tt_keep); 821 callout_stop(tp->tt_2msl); 822 callout_stop(tp->tt_delack); 823 824 if (tp->t_flags & TF_ONOUTPUTQ) { 825 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid); 826 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq); 827 tp->t_flags &= ~TF_ONOUTPUTQ; 828 } 829 830 /* 831 * If we got enough samples through the srtt filter, 832 * save the rtt and rttvar in the routing entry. 833 * 'Enough' is arbitrarily defined as the 16 samples. 834 * 16 samples is enough for the srtt filter to converge 835 * to within 5% of the correct value; fewer samples and 836 * we could save a very bogus rtt. 837 * 838 * Don't update the default route's characteristics and don't 839 * update anything that the user "locked". 840 */ 841 if (tp->t_rttupdated >= 16) { 842 u_long i = 0; 843 844 if (isipv6) { 845 struct sockaddr_in6 *sin6; 846 847 if ((rt = inp->in6p_route.ro_rt) == NULL) 848 goto no_valid_rt; 849 sin6 = (struct sockaddr_in6 *)rt_key(rt); 850 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 851 goto no_valid_rt; 852 } else 853 if ((rt = inp->inp_route.ro_rt) == NULL || 854 ((struct sockaddr_in *)rt_key(rt))-> 855 sin_addr.s_addr == INADDR_ANY) 856 goto no_valid_rt; 857 858 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) { 859 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 860 if (rt->rt_rmx.rmx_rtt && i) 861 /* 862 * filter this update to half the old & half 863 * the new values, converting scale. 864 * See route.h and tcp_var.h for a 865 * description of the scaling constants. 866 */ 867 rt->rt_rmx.rmx_rtt = 868 (rt->rt_rmx.rmx_rtt + i) / 2; 869 else 870 rt->rt_rmx.rmx_rtt = i; 871 tcpstat.tcps_cachedrtt++; 872 } 873 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) { 874 i = tp->t_rttvar * 875 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 876 if (rt->rt_rmx.rmx_rttvar && i) 877 rt->rt_rmx.rmx_rttvar = 878 (rt->rt_rmx.rmx_rttvar + i) / 2; 879 else 880 rt->rt_rmx.rmx_rttvar = i; 881 tcpstat.tcps_cachedrttvar++; 882 } 883 /* 884 * The old comment here said: 885 * update the pipelimit (ssthresh) if it has been updated 886 * already or if a pipesize was specified & the threshhold 887 * got below half the pipesize. I.e., wait for bad news 888 * before we start updating, then update on both good 889 * and bad news. 890 * 891 * But we want to save the ssthresh even if no pipesize is 892 * specified explicitly in the route, because such 893 * connections still have an implicit pipesize specified 894 * by the global tcp_sendspace. In the absence of a reliable 895 * way to calculate the pipesize, it will have to do. 896 */ 897 i = tp->snd_ssthresh; 898 if (rt->rt_rmx.rmx_sendpipe != 0) 899 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2); 900 else 901 dosavessthresh = (i < so->so_snd.sb_hiwat/2); 902 if (dosavessthresh || 903 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) && 904 (rt->rt_rmx.rmx_ssthresh != 0))) { 905 /* 906 * convert the limit from user data bytes to 907 * packets then to packet data bytes. 908 */ 909 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 910 if (i < 2) 911 i = 2; 912 i *= tp->t_maxseg + 913 (isipv6 ? 914 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 915 sizeof(struct tcpiphdr)); 916 if (rt->rt_rmx.rmx_ssthresh) 917 rt->rt_rmx.rmx_ssthresh = 918 (rt->rt_rmx.rmx_ssthresh + i) / 2; 919 else 920 rt->rt_rmx.rmx_ssthresh = i; 921 tcpstat.tcps_cachedssthresh++; 922 } 923 } 924 925 no_valid_rt: 926 /* free the reassembly queue, if any */ 927 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 928 LIST_REMOVE(q, tqe_q); 929 m_freem(q->tqe_m); 930 FREE(q, M_TSEGQ); 931 tcp_reass_qsize--; 932 } 933 /* throw away SACK blocks in scoreboard*/ 934 if (TCP_DO_SACK(tp)) 935 tcp_sack_cleanup(&tp->scb); 936 937 inp->inp_ppcb = NULL; 938 soisdisconnected(so); 939 /* 940 * Discard the inp. In the SMP case a wildcard inp's hash (created 941 * by a listen socket or an INADDR_ANY udp socket) is replicated 942 * for each protocol thread and must be removed in the context of 943 * that thread. This is accomplished by chaining the message 944 * through the cpus. 945 * 946 * If the inp is not wildcarded we simply detach, which will remove 947 * the any hashes still present for this inp. 948 */ 949 #ifdef SMP 950 if (inp->inp_flags & INP_WILDCARD_MP) { 951 struct netmsg_remwildcard *msg; 952 953 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2; 954 msg = malloc(sizeof(struct netmsg_remwildcard), 955 M_LWKTMSG, M_INTWAIT); 956 lwkt_initmsg(&msg->nm_lmsg, &netisr_afree_rport, 0, 957 lwkt_cmd_func(in_pcbremwildcardhash_handler), 958 lwkt_cmd_op_none); 959 #ifdef INET6 960 msg->nm_isinet6 = isafinet6; 961 #endif 962 msg->nm_inp = inp; 963 msg->nm_pcbinfo = &tcbinfo[cpu]; 964 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_lmsg); 965 } else 966 #endif 967 { 968 /* note: detach removes any wildcard hash entry */ 969 #ifdef INET6 970 if (isafinet6) 971 in6_pcbdetach(inp); 972 else 973 #endif 974 in_pcbdetach(inp); 975 } 976 tcpstat.tcps_closed++; 977 return (NULL); 978 } 979 980 static __inline void 981 tcp_drain_oncpu(struct inpcbhead *head) 982 { 983 struct inpcb *inpb; 984 struct tcpcb *tcpb; 985 struct tseg_qent *te; 986 987 LIST_FOREACH(inpb, head, inp_list) { 988 if (inpb->inp_flags & INP_PLACEMARKER) 989 continue; 990 if ((tcpb = intotcpcb(inpb))) { 991 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) { 992 LIST_REMOVE(te, tqe_q); 993 m_freem(te->tqe_m); 994 FREE(te, M_TSEGQ); 995 tcp_reass_qsize--; 996 } 997 } 998 } 999 } 1000 1001 #ifdef SMP 1002 struct netmsg_tcp_drain { 1003 struct lwkt_msg nm_lmsg; 1004 struct inpcbhead *nm_head; 1005 }; 1006 1007 static int 1008 tcp_drain_handler(lwkt_msg_t lmsg) 1009 { 1010 struct netmsg_tcp_drain *nm = (void *)lmsg; 1011 1012 tcp_drain_oncpu(nm->nm_head); 1013 lwkt_replymsg(lmsg, 0); 1014 return(EASYNC); 1015 } 1016 #endif 1017 1018 void 1019 tcp_drain() 1020 { 1021 #ifdef SMP 1022 int cpu; 1023 #endif 1024 1025 if (!do_tcpdrain) 1026 return; 1027 1028 /* 1029 * Walk the tcpbs, if existing, and flush the reassembly queue, 1030 * if there is one... 1031 * XXX: The "Net/3" implementation doesn't imply that the TCP 1032 * reassembly queue should be flushed, but in a situation 1033 * where we're really low on mbufs, this is potentially 1034 * useful. 1035 */ 1036 #ifdef SMP 1037 for (cpu = 0; cpu < ncpus2; cpu++) { 1038 struct netmsg_tcp_drain *msg; 1039 1040 if (cpu == mycpu->gd_cpuid) { 1041 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead); 1042 } else { 1043 msg = malloc(sizeof(struct netmsg_tcp_drain), 1044 M_LWKTMSG, M_NOWAIT); 1045 if (msg == NULL) 1046 continue; 1047 lwkt_initmsg(&msg->nm_lmsg, &netisr_afree_rport, 0, 1048 lwkt_cmd_func(tcp_drain_handler), 1049 lwkt_cmd_op_none); 1050 msg->nm_head = &tcbinfo[cpu].pcblisthead; 1051 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_lmsg); 1052 } 1053 } 1054 #else 1055 tcp_drain_oncpu(&tcbinfo[0].pcblisthead); 1056 #endif 1057 } 1058 1059 /* 1060 * Notify a tcp user of an asynchronous error; 1061 * store error as soft error, but wake up user 1062 * (for now, won't do anything until can select for soft error). 1063 * 1064 * Do not wake up user since there currently is no mechanism for 1065 * reporting soft errors (yet - a kqueue filter may be added). 1066 */ 1067 static void 1068 tcp_notify(struct inpcb *inp, int error) 1069 { 1070 struct tcpcb *tp = intotcpcb(inp); 1071 1072 /* 1073 * Ignore some errors if we are hooked up. 1074 * If connection hasn't completed, has retransmitted several times, 1075 * and receives a second error, give up now. This is better 1076 * than waiting a long time to establish a connection that 1077 * can never complete. 1078 */ 1079 if (tp->t_state == TCPS_ESTABLISHED && 1080 (error == EHOSTUNREACH || error == ENETUNREACH || 1081 error == EHOSTDOWN)) { 1082 return; 1083 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1084 tp->t_softerror) 1085 tcp_drop(tp, error); 1086 else 1087 tp->t_softerror = error; 1088 #if 0 1089 wakeup(&so->so_timeo); 1090 sorwakeup(so); 1091 sowwakeup(so); 1092 #endif 1093 } 1094 1095 static int 1096 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1097 { 1098 int error, i, n; 1099 struct inpcb *marker; 1100 struct inpcb *inp; 1101 inp_gen_t gencnt; 1102 globaldata_t gd; 1103 int origcpu, ccpu; 1104 1105 error = 0; 1106 n = 0; 1107 1108 /* 1109 * The process of preparing the TCB list is too time-consuming and 1110 * resource-intensive to repeat twice on every request. 1111 */ 1112 if (req->oldptr == NULL) { 1113 for (ccpu = 0; ccpu < ncpus; ++ccpu) { 1114 gd = globaldata_find(ccpu); 1115 n += tcbinfo[gd->gd_cpuid].ipi_count; 1116 } 1117 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb); 1118 return (0); 1119 } 1120 1121 if (req->newptr != NULL) 1122 return (EPERM); 1123 1124 marker = malloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1125 marker->inp_flags |= INP_PLACEMARKER; 1126 1127 /* 1128 * OK, now we're committed to doing something. Run the inpcb list 1129 * for each cpu in the system and construct the output. Use a 1130 * list placemarker to deal with list changes occuring during 1131 * copyout blockages (but otherwise depend on being on the correct 1132 * cpu to avoid races). 1133 */ 1134 origcpu = mycpu->gd_cpuid; 1135 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) { 1136 globaldata_t rgd; 1137 caddr_t inp_ppcb; 1138 struct xtcpcb xt; 1139 int cpu_id; 1140 1141 cpu_id = (origcpu + ccpu) % ncpus; 1142 if ((smp_active_mask & (1 << cpu_id)) == 0) 1143 continue; 1144 rgd = globaldata_find(cpu_id); 1145 lwkt_setcpu_self(rgd); 1146 1147 /* indicate change of CPU */ 1148 cpu_mb1(); 1149 1150 gencnt = tcbinfo[cpu_id].ipi_gencnt; 1151 n = tcbinfo[cpu_id].ipi_count; 1152 1153 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list); 1154 i = 0; 1155 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) { 1156 /* 1157 * process a snapshot of pcbs, ignoring placemarkers 1158 * and using our own to allow SYSCTL_OUT to block. 1159 */ 1160 LIST_REMOVE(marker, inp_list); 1161 LIST_INSERT_AFTER(inp, marker, inp_list); 1162 1163 if (inp->inp_flags & INP_PLACEMARKER) 1164 continue; 1165 if (inp->inp_gencnt > gencnt) 1166 continue; 1167 if (prison_xinpcb(req->td, inp)) 1168 continue; 1169 1170 xt.xt_len = sizeof xt; 1171 bcopy(inp, &xt.xt_inp, sizeof *inp); 1172 inp_ppcb = inp->inp_ppcb; 1173 if (inp_ppcb != NULL) 1174 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1175 else 1176 bzero(&xt.xt_tp, sizeof xt.xt_tp); 1177 if (inp->inp_socket) 1178 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1179 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0) 1180 break; 1181 ++i; 1182 } 1183 LIST_REMOVE(marker, inp_list); 1184 if (error == 0 && i < n) { 1185 bzero(&xt, sizeof xt); 1186 xt.xt_len = sizeof xt; 1187 while (i < n) { 1188 error = SYSCTL_OUT(req, &xt, sizeof xt); 1189 if (error) 1190 break; 1191 ++i; 1192 } 1193 } 1194 } 1195 1196 /* 1197 * Make sure we are on the same cpu we were on originally, since 1198 * higher level callers expect this. Also don't pollute caches with 1199 * migrated userland data by (eventually) returning to userland 1200 * on a different cpu. 1201 */ 1202 lwkt_setcpu_self(globaldata_find(origcpu)); 1203 free(marker, M_TEMP); 1204 return (error); 1205 } 1206 1207 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1208 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1209 1210 static int 1211 tcp_getcred(SYSCTL_HANDLER_ARGS) 1212 { 1213 struct sockaddr_in addrs[2]; 1214 struct inpcb *inp; 1215 int cpu; 1216 int error, s; 1217 1218 error = suser(req->td); 1219 if (error != 0) 1220 return (error); 1221 error = SYSCTL_IN(req, addrs, sizeof addrs); 1222 if (error != 0) 1223 return (error); 1224 s = splnet(); 1225 1226 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1227 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1228 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1229 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1230 if (inp == NULL || inp->inp_socket == NULL) { 1231 error = ENOENT; 1232 goto out; 1233 } 1234 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1235 out: 1236 splx(s); 1237 return (error); 1238 } 1239 1240 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1241 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1242 1243 #ifdef INET6 1244 static int 1245 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1246 { 1247 struct sockaddr_in6 addrs[2]; 1248 struct inpcb *inp; 1249 int error, s; 1250 boolean_t mapped = FALSE; 1251 1252 error = suser(req->td); 1253 if (error != 0) 1254 return (error); 1255 error = SYSCTL_IN(req, addrs, sizeof addrs); 1256 if (error != 0) 1257 return (error); 1258 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1259 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1260 mapped = TRUE; 1261 else 1262 return (EINVAL); 1263 } 1264 s = splnet(); 1265 if (mapped) { 1266 inp = in_pcblookup_hash(&tcbinfo[0], 1267 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1268 addrs[1].sin6_port, 1269 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1270 addrs[0].sin6_port, 1271 0, NULL); 1272 } else { 1273 inp = in6_pcblookup_hash(&tcbinfo[0], 1274 &addrs[1].sin6_addr, addrs[1].sin6_port, 1275 &addrs[0].sin6_addr, addrs[0].sin6_port, 1276 0, NULL); 1277 } 1278 if (inp == NULL || inp->inp_socket == NULL) { 1279 error = ENOENT; 1280 goto out; 1281 } 1282 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1283 out: 1284 splx(s); 1285 return (error); 1286 } 1287 1288 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1289 0, 0, 1290 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1291 #endif 1292 1293 void 1294 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1295 { 1296 struct ip *ip = vip; 1297 struct tcphdr *th; 1298 struct in_addr faddr; 1299 struct inpcb *inp; 1300 struct tcpcb *tp; 1301 void (*notify)(struct inpcb *, int) = tcp_notify; 1302 tcp_seq icmpseq; 1303 int arg, cpu, s; 1304 1305 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) { 1306 return; 1307 } 1308 1309 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1310 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1311 return; 1312 1313 arg = inetctlerrmap[cmd]; 1314 if (cmd == PRC_QUENCH) { 1315 notify = tcp_quench; 1316 } else if (icmp_may_rst && 1317 (cmd == PRC_UNREACH_ADMIN_PROHIB || 1318 cmd == PRC_UNREACH_PORT || 1319 cmd == PRC_TIMXCEED_INTRANS) && 1320 ip != NULL) { 1321 notify = tcp_drop_syn_sent; 1322 } else if (cmd == PRC_MSGSIZE) { 1323 struct icmp *icmp = (struct icmp *) 1324 ((caddr_t)ip - offsetof(struct icmp, icmp_ip)); 1325 1326 arg = ntohs(icmp->icmp_nextmtu); 1327 notify = tcp_mtudisc; 1328 } else if (PRC_IS_REDIRECT(cmd)) { 1329 ip = NULL; 1330 notify = in_rtchange; 1331 } else if (cmd == PRC_HOSTDEAD) { 1332 ip = NULL; 1333 } 1334 1335 if (ip != NULL) { 1336 s = splnet(); 1337 th = (struct tcphdr *)((caddr_t)ip + 1338 (IP_VHL_HL(ip->ip_vhl) << 2)); 1339 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1340 ip->ip_src.s_addr, th->th_sport); 1341 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1342 ip->ip_src, th->th_sport, 0, NULL); 1343 if ((inp != NULL) && (inp->inp_socket != NULL)) { 1344 icmpseq = htonl(th->th_seq); 1345 tp = intotcpcb(inp); 1346 if (SEQ_GEQ(icmpseq, tp->snd_una) && 1347 SEQ_LT(icmpseq, tp->snd_max)) 1348 (*notify)(inp, arg); 1349 } else { 1350 struct in_conninfo inc; 1351 1352 inc.inc_fport = th->th_dport; 1353 inc.inc_lport = th->th_sport; 1354 inc.inc_faddr = faddr; 1355 inc.inc_laddr = ip->ip_src; 1356 #ifdef INET6 1357 inc.inc_isipv6 = 0; 1358 #endif 1359 syncache_unreach(&inc, th); 1360 } 1361 splx(s); 1362 } else { 1363 for (cpu = 0; cpu < ncpus2; cpu++) { 1364 in_pcbnotifyall(&tcbinfo[cpu].pcblisthead, faddr, arg, 1365 notify); 1366 } 1367 } 1368 } 1369 1370 #ifdef INET6 1371 void 1372 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1373 { 1374 struct tcphdr th; 1375 void (*notify) (struct inpcb *, int) = tcp_notify; 1376 struct ip6_hdr *ip6; 1377 struct mbuf *m; 1378 struct ip6ctlparam *ip6cp = NULL; 1379 const struct sockaddr_in6 *sa6_src = NULL; 1380 int off; 1381 struct tcp_portonly { 1382 u_int16_t th_sport; 1383 u_int16_t th_dport; 1384 } *thp; 1385 int arg; 1386 1387 if (sa->sa_family != AF_INET6 || 1388 sa->sa_len != sizeof(struct sockaddr_in6)) 1389 return; 1390 1391 arg = 0; 1392 if (cmd == PRC_QUENCH) 1393 notify = tcp_quench; 1394 else if (cmd == PRC_MSGSIZE) { 1395 struct ip6ctlparam *ip6cp = d; 1396 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6; 1397 1398 arg = ntohl(icmp6->icmp6_mtu); 1399 notify = tcp_mtudisc; 1400 } else if (!PRC_IS_REDIRECT(cmd) && 1401 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) { 1402 return; 1403 } 1404 1405 /* if the parameter is from icmp6, decode it. */ 1406 if (d != NULL) { 1407 ip6cp = (struct ip6ctlparam *)d; 1408 m = ip6cp->ip6c_m; 1409 ip6 = ip6cp->ip6c_ip6; 1410 off = ip6cp->ip6c_off; 1411 sa6_src = ip6cp->ip6c_src; 1412 } else { 1413 m = NULL; 1414 ip6 = NULL; 1415 off = 0; /* fool gcc */ 1416 sa6_src = &sa6_any; 1417 } 1418 1419 if (ip6 != NULL) { 1420 struct in_conninfo inc; 1421 /* 1422 * XXX: We assume that when IPV6 is non NULL, 1423 * M and OFF are valid. 1424 */ 1425 1426 /* check if we can safely examine src and dst ports */ 1427 if (m->m_pkthdr.len < off + sizeof *thp) 1428 return; 1429 1430 bzero(&th, sizeof th); 1431 m_copydata(m, off, sizeof *thp, (caddr_t)&th); 1432 1433 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport, 1434 (struct sockaddr *)ip6cp->ip6c_src, 1435 th.th_sport, cmd, arg, notify); 1436 1437 inc.inc_fport = th.th_dport; 1438 inc.inc_lport = th.th_sport; 1439 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1440 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1441 inc.inc_isipv6 = 1; 1442 syncache_unreach(&inc, &th); 1443 } else 1444 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0, 1445 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify); 1446 } 1447 #endif 1448 1449 /* 1450 * Following is where TCP initial sequence number generation occurs. 1451 * 1452 * There are two places where we must use initial sequence numbers: 1453 * 1. In SYN-ACK packets. 1454 * 2. In SYN packets. 1455 * 1456 * All ISNs for SYN-ACK packets are generated by the syncache. See 1457 * tcp_syncache.c for details. 1458 * 1459 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1460 * depends on this property. In addition, these ISNs should be 1461 * unguessable so as to prevent connection hijacking. To satisfy 1462 * the requirements of this situation, the algorithm outlined in 1463 * RFC 1948 is used to generate sequence numbers. 1464 * 1465 * Implementation details: 1466 * 1467 * Time is based off the system timer, and is corrected so that it 1468 * increases by one megabyte per second. This allows for proper 1469 * recycling on high speed LANs while still leaving over an hour 1470 * before rollover. 1471 * 1472 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1473 * between seeding of isn_secret. This is normally set to zero, 1474 * as reseeding should not be necessary. 1475 * 1476 */ 1477 1478 #define ISN_BYTES_PER_SECOND 1048576 1479 1480 u_char isn_secret[32]; 1481 int isn_last_reseed; 1482 MD5_CTX isn_ctx; 1483 1484 tcp_seq 1485 tcp_new_isn(struct tcpcb *tp) 1486 { 1487 u_int32_t md5_buffer[4]; 1488 tcp_seq new_isn; 1489 1490 /* Seed if this is the first use, reseed if requested. */ 1491 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1492 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1493 < (u_int)ticks))) { 1494 read_random_unlimited(&isn_secret, sizeof isn_secret); 1495 isn_last_reseed = ticks; 1496 } 1497 1498 /* Compute the md5 hash and return the ISN. */ 1499 MD5Init(&isn_ctx); 1500 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 1501 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 1502 #ifdef INET6 1503 if (tp->t_inpcb->inp_vflag & INP_IPV6) { 1504 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1505 sizeof(struct in6_addr)); 1506 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1507 sizeof(struct in6_addr)); 1508 } else 1509 #endif 1510 { 1511 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1512 sizeof(struct in_addr)); 1513 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1514 sizeof(struct in_addr)); 1515 } 1516 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1517 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1518 new_isn = (tcp_seq) md5_buffer[0]; 1519 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1520 return (new_isn); 1521 } 1522 1523 /* 1524 * When a source quench is received, close congestion window 1525 * to one segment. We will gradually open it again as we proceed. 1526 */ 1527 void 1528 tcp_quench(struct inpcb *inp, int errno) 1529 { 1530 struct tcpcb *tp = intotcpcb(inp); 1531 1532 if (tp != NULL) 1533 tp->snd_cwnd = tp->t_maxseg; 1534 } 1535 1536 /* 1537 * When a specific ICMP unreachable message is received and the 1538 * connection state is SYN-SENT, drop the connection. This behavior 1539 * is controlled by the icmp_may_rst sysctl. 1540 */ 1541 void 1542 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1543 { 1544 struct tcpcb *tp = intotcpcb(inp); 1545 1546 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT)) 1547 tcp_drop(tp, errno); 1548 } 1549 1550 /* 1551 * When a `need fragmentation' ICMP is received, update our idea of the MSS 1552 * based on the new value in the route. Also nudge TCP to send something, 1553 * since we know the packet we just sent was dropped. 1554 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1555 */ 1556 void 1557 tcp_mtudisc(struct inpcb *inp, int mtu) 1558 { 1559 struct tcpcb *tp = intotcpcb(inp); 1560 struct rtentry *rt; 1561 struct socket *so = inp->inp_socket; 1562 int maxopd, mss; 1563 #ifdef INET6 1564 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0); 1565 #else 1566 const boolean_t isipv6 = FALSE; 1567 #endif 1568 1569 if (tp == NULL) 1570 return; 1571 1572 /* 1573 * If no MTU is provided in the ICMP message, use the 1574 * next lower likely value, as specified in RFC 1191. 1575 */ 1576 if (mtu == 0) { 1577 int oldmtu; 1578 1579 oldmtu = tp->t_maxopd + 1580 (isipv6 ? 1581 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1582 sizeof(struct tcpiphdr)); 1583 mtu = ip_next_mtu(oldmtu, 0); 1584 } 1585 1586 if (isipv6) 1587 rt = tcp_rtlookup6(&inp->inp_inc); 1588 else 1589 rt = tcp_rtlookup(&inp->inp_inc); 1590 if (rt != NULL) { 1591 struct rmxp_tao *taop = rmx_taop(rt->rt_rmx); 1592 1593 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu) 1594 mtu = rt->rt_rmx.rmx_mtu; 1595 1596 maxopd = mtu - 1597 (isipv6 ? 1598 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1599 sizeof(struct tcpiphdr)); 1600 1601 /* 1602 * XXX - The following conditional probably violates the TCP 1603 * spec. The problem is that, since we don't know the 1604 * other end's MSS, we are supposed to use a conservative 1605 * default. But, if we do that, then MTU discovery will 1606 * never actually take place, because the conservative 1607 * default is much less than the MTUs typically seen 1608 * on the Internet today. For the moment, we'll sweep 1609 * this under the carpet. 1610 * 1611 * The conservative default might not actually be a problem 1612 * if the only case this occurs is when sending an initial 1613 * SYN with options and data to a host we've never talked 1614 * to before. Then, they will reply with an MSS value which 1615 * will get recorded and the new parameters should get 1616 * recomputed. For Further Study. 1617 */ 1618 if (taop->tao_mssopt != 0 && taop->tao_mssopt < maxopd) 1619 maxopd = taop->tao_mssopt; 1620 } else 1621 maxopd = mtu - 1622 (isipv6 ? 1623 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1624 sizeof(struct tcpiphdr)); 1625 1626 if (tp->t_maxopd <= maxopd) 1627 return; 1628 tp->t_maxopd = maxopd; 1629 1630 mss = maxopd; 1631 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) == 1632 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1633 mss -= TCPOLEN_TSTAMP_APPA; 1634 1635 if ((tp->t_flags & (TF_REQ_CC | TF_RCVD_CC | TF_NOOPT)) == 1636 (TF_REQ_CC | TF_RCVD_CC)) 1637 mss -= TCPOLEN_CC_APPA; 1638 1639 /* round down to multiple of MCLBYTES */ 1640 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */ 1641 if (mss > MCLBYTES) 1642 mss &= ~(MCLBYTES - 1); 1643 #else 1644 if (mss > MCLBYTES) 1645 mss = (mss / MCLBYTES) * MCLBYTES; 1646 #endif 1647 1648 if (so->so_snd.sb_hiwat < mss) 1649 mss = so->so_snd.sb_hiwat; 1650 1651 tp->t_maxseg = mss; 1652 tp->t_rtttime = 0; 1653 tp->snd_nxt = tp->snd_una; 1654 tcp_output(tp); 1655 tcpstat.tcps_mturesent++; 1656 } 1657 1658 /* 1659 * Look-up the routing entry to the peer of this inpcb. If no route 1660 * is found and it cannot be allocated the return NULL. This routine 1661 * is called by TCP routines that access the rmx structure and by tcp_mss 1662 * to get the interface MTU. 1663 */ 1664 struct rtentry * 1665 tcp_rtlookup(struct in_conninfo *inc) 1666 { 1667 struct route *ro = &inc->inc_route; 1668 1669 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) { 1670 /* No route yet, so try to acquire one */ 1671 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1672 /* 1673 * unused portions of the structure MUST be zero'd 1674 * out because rtalloc() treats it as opaque data 1675 */ 1676 bzero(&ro->ro_dst, sizeof(struct sockaddr_in)); 1677 ro->ro_dst.sa_family = AF_INET; 1678 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1679 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1680 inc->inc_faddr; 1681 rtalloc(ro); 1682 } 1683 } 1684 return (ro->ro_rt); 1685 } 1686 1687 #ifdef INET6 1688 struct rtentry * 1689 tcp_rtlookup6(struct in_conninfo *inc) 1690 { 1691 struct route_in6 *ro6 = &inc->inc6_route; 1692 1693 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) { 1694 /* No route yet, so try to acquire one */ 1695 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1696 /* 1697 * unused portions of the structure MUST be zero'd 1698 * out because rtalloc() treats it as opaque data 1699 */ 1700 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6)); 1701 ro6->ro_dst.sin6_family = AF_INET6; 1702 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1703 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1704 rtalloc((struct route *)ro6); 1705 } 1706 } 1707 return (ro6->ro_rt); 1708 } 1709 #endif 1710 1711 #ifdef IPSEC 1712 /* compute ESP/AH header size for TCP, including outer IP header. */ 1713 size_t 1714 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1715 { 1716 struct inpcb *inp; 1717 struct mbuf *m; 1718 size_t hdrsiz; 1719 struct ip *ip; 1720 struct tcphdr *th; 1721 1722 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1723 return (0); 1724 MGETHDR(m, MB_DONTWAIT, MT_DATA); 1725 if (!m) 1726 return (0); 1727 1728 #ifdef INET6 1729 if (inp->inp_vflag & INP_IPV6) { 1730 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 1731 1732 th = (struct tcphdr *)(ip6 + 1); 1733 m->m_pkthdr.len = m->m_len = 1734 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1735 tcp_fillheaders(tp, ip6, th); 1736 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1737 } else 1738 #endif 1739 { 1740 ip = mtod(m, struct ip *); 1741 th = (struct tcphdr *)(ip + 1); 1742 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1743 tcp_fillheaders(tp, ip, th); 1744 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1745 } 1746 1747 m_free(m); 1748 return (hdrsiz); 1749 } 1750 #endif 1751 1752 /* 1753 * Return a pointer to the cached information about the remote host. 1754 * The cached information is stored in the protocol specific part of 1755 * the route metrics. 1756 */ 1757 struct rmxp_tao * 1758 tcp_gettaocache(struct in_conninfo *inc) 1759 { 1760 struct rtentry *rt; 1761 1762 #ifdef INET6 1763 if (inc->inc_isipv6) 1764 rt = tcp_rtlookup6(inc); 1765 else 1766 #endif 1767 rt = tcp_rtlookup(inc); 1768 1769 /* Make sure this is a host route and is up. */ 1770 if (rt == NULL || 1771 (rt->rt_flags & (RTF_UP | RTF_HOST)) != (RTF_UP | RTF_HOST)) 1772 return (NULL); 1773 1774 return (rmx_taop(rt->rt_rmx)); 1775 } 1776 1777 /* 1778 * Clear all the TAO cache entries, called from tcp_init. 1779 * 1780 * XXX 1781 * This routine is just an empty one, because we assume that the routing 1782 * routing tables are initialized at the same time when TCP, so there is 1783 * nothing in the cache left over. 1784 */ 1785 static void 1786 tcp_cleartaocache() 1787 { 1788 } 1789 1790 /* 1791 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1792 * 1793 * This code attempts to calculate the bandwidth-delay product as a 1794 * means of determining the optimal window size to maximize bandwidth, 1795 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1796 * routers. This code also does a fairly good job keeping RTTs in check 1797 * across slow links like modems. We implement an algorithm which is very 1798 * similar (but not meant to be) TCP/Vegas. The code operates on the 1799 * transmitter side of a TCP connection and so only effects the transmit 1800 * side of the connection. 1801 * 1802 * BACKGROUND: TCP makes no provision for the management of buffer space 1803 * at the end points or at the intermediate routers and switches. A TCP 1804 * stream, whether using NewReno or not, will eventually buffer as 1805 * many packets as it is able and the only reason this typically works is 1806 * due to the fairly small default buffers made available for a connection 1807 * (typicaly 16K or 32K). As machines use larger windows and/or window 1808 * scaling it is now fairly easy for even a single TCP connection to blow-out 1809 * all available buffer space not only on the local interface, but on 1810 * intermediate routers and switches as well. NewReno makes a misguided 1811 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1812 * then backing off, then steadily increasing the window again until another 1813 * failure occurs, ad-infinitum. This results in terrible oscillation that 1814 * is only made worse as network loads increase and the idea of intentionally 1815 * blowing out network buffers is, frankly, a terrible way to manage network 1816 * resources. 1817 * 1818 * It is far better to limit the transmit window prior to the failure 1819 * condition being achieved. There are two general ways to do this: First 1820 * you can 'scan' through different transmit window sizes and locate the 1821 * point where the RTT stops increasing, indicating that you have filled the 1822 * pipe, then scan backwards until you note that RTT stops decreasing, then 1823 * repeat ad-infinitum. This method works in principle but has severe 1824 * implementation issues due to RTT variances, timer granularity, and 1825 * instability in the algorithm which can lead to many false positives and 1826 * create oscillations as well as interact badly with other TCP streams 1827 * implementing the same algorithm. 1828 * 1829 * The second method is to limit the window to the bandwidth delay product 1830 * of the link. This is the method we implement. RTT variances and our 1831 * own manipulation of the congestion window, bwnd, can potentially 1832 * destabilize the algorithm. For this reason we have to stabilize the 1833 * elements used to calculate the window. We do this by using the minimum 1834 * observed RTT, the long term average of the observed bandwidth, and 1835 * by adding two segments worth of slop. It isn't perfect but it is able 1836 * to react to changing conditions and gives us a very stable basis on 1837 * which to extend the algorithm. 1838 */ 1839 void 1840 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1841 { 1842 u_long bw; 1843 u_long bwnd; 1844 int save_ticks; 1845 int delta_ticks; 1846 1847 /* 1848 * If inflight_enable is disabled in the middle of a tcp connection, 1849 * make sure snd_bwnd is effectively disabled. 1850 */ 1851 if (!tcp_inflight_enable) { 1852 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1853 tp->snd_bandwidth = 0; 1854 return; 1855 } 1856 1857 /* 1858 * Validate the delta time. If a connection is new or has been idle 1859 * a long time we have to reset the bandwidth calculator. 1860 */ 1861 save_ticks = ticks; 1862 delta_ticks = save_ticks - tp->t_bw_rtttime; 1863 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) { 1864 tp->t_bw_rtttime = ticks; 1865 tp->t_bw_rtseq = ack_seq; 1866 if (tp->snd_bandwidth == 0) 1867 tp->snd_bandwidth = tcp_inflight_min; 1868 return; 1869 } 1870 if (delta_ticks == 0) 1871 return; 1872 1873 /* 1874 * Sanity check, plus ignore pure window update acks. 1875 */ 1876 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0) 1877 return; 1878 1879 /* 1880 * Figure out the bandwidth. Due to the tick granularity this 1881 * is a very rough number and it MUST be averaged over a fairly 1882 * long period of time. XXX we need to take into account a link 1883 * that is not using all available bandwidth, but for now our 1884 * slop will ramp us up if this case occurs and the bandwidth later 1885 * increases. 1886 */ 1887 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks; 1888 tp->t_bw_rtttime = save_ticks; 1889 tp->t_bw_rtseq = ack_seq; 1890 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1891 1892 tp->snd_bandwidth = bw; 1893 1894 /* 1895 * Calculate the semi-static bandwidth delay product, plus two maximal 1896 * segments. The additional slop puts us squarely in the sweet 1897 * spot and also handles the bandwidth run-up case. Without the 1898 * slop we could be locking ourselves into a lower bandwidth. 1899 * 1900 * Situations Handled: 1901 * (1) Prevents over-queueing of packets on LANs, especially on 1902 * high speed LANs, allowing larger TCP buffers to be 1903 * specified, and also does a good job preventing 1904 * over-queueing of packets over choke points like modems 1905 * (at least for the transmit side). 1906 * 1907 * (2) Is able to handle changing network loads (bandwidth 1908 * drops so bwnd drops, bandwidth increases so bwnd 1909 * increases). 1910 * 1911 * (3) Theoretically should stabilize in the face of multiple 1912 * connections implementing the same algorithm (this may need 1913 * a little work). 1914 * 1915 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1916 * be adjusted with a sysctl but typically only needs to be on 1917 * very slow connections. A value no smaller then 5 should 1918 * be used, but only reduce this default if you have no other 1919 * choice. 1920 */ 1921 1922 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1923 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + 1924 tcp_inflight_stab * (int)tp->t_maxseg / 10; 1925 #undef USERTT 1926 1927 if (tcp_inflight_debug > 0) { 1928 static int ltime; 1929 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1930 ltime = ticks; 1931 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1932 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd); 1933 } 1934 } 1935 if ((long)bwnd < tcp_inflight_min) 1936 bwnd = tcp_inflight_min; 1937 if (bwnd > tcp_inflight_max) 1938 bwnd = tcp_inflight_max; 1939 if ((long)bwnd < tp->t_maxseg * 2) 1940 bwnd = tp->t_maxseg * 2; 1941 tp->snd_bwnd = bwnd; 1942 } 1943