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 1.47 2005/04/22 17:41:15 joerg 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_percpu[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_percpu[cpu], 252 sizeof(struct tcp_stats)))) 253 break; 254 if ((error = SYSCTL_IN(req, &tcpstats_percpu[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 counters for each CPU. 370 */ 371 #ifdef SMP 372 for (cpu = 0; cpu < ncpus; ++cpu) { 373 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats)); 374 } 375 #else 376 bzero(&tcpstat, sizeof(struct tcp_stats)); 377 #endif 378 379 syncache_init(); 380 tcp_sack_init(); 381 tcp_thread_init(); 382 } 383 384 void 385 tcpmsg_service_loop(void *dummy) 386 { 387 struct netmsg *msg; 388 389 while ((msg = lwkt_waitport(&curthread->td_msgport, NULL))) { 390 do { 391 msg->nm_lmsg.ms_cmd.cm_func(&msg->nm_lmsg); 392 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL); 393 tcp_willblock(); 394 } 395 } 396 397 static void 398 tcp_willblock(void) 399 { 400 struct tcpcb *tp; 401 int cpu = mycpu->gd_cpuid; 402 403 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) { 404 KKASSERT(tp->t_flags & TF_ONOUTPUTQ); 405 tp->t_flags &= ~TF_ONOUTPUTQ; 406 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq); 407 tcp_output(tp); 408 } 409 } 410 411 412 /* 413 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 414 * tcp_template used to store this data in mbufs, but we now recopy it out 415 * of the tcpcb each time to conserve mbufs. 416 */ 417 void 418 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr) 419 { 420 struct inpcb *inp = tp->t_inpcb; 421 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 422 423 #ifdef INET6 424 if (inp->inp_vflag & INP_IPV6) { 425 struct ip6_hdr *ip6; 426 427 ip6 = (struct ip6_hdr *)ip_ptr; 428 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 429 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 430 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 431 (IPV6_VERSION & IPV6_VERSION_MASK); 432 ip6->ip6_nxt = IPPROTO_TCP; 433 ip6->ip6_plen = sizeof(struct tcphdr); 434 ip6->ip6_src = inp->in6p_laddr; 435 ip6->ip6_dst = inp->in6p_faddr; 436 tcp_hdr->th_sum = 0; 437 } else 438 #endif 439 { 440 struct ip *ip = (struct ip *) ip_ptr; 441 442 ip->ip_vhl = IP_VHL_BORING; 443 ip->ip_tos = 0; 444 ip->ip_len = 0; 445 ip->ip_id = 0; 446 ip->ip_off = 0; 447 ip->ip_ttl = 0; 448 ip->ip_sum = 0; 449 ip->ip_p = IPPROTO_TCP; 450 ip->ip_src = inp->inp_laddr; 451 ip->ip_dst = inp->inp_faddr; 452 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, 453 ip->ip_dst.s_addr, 454 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 455 } 456 457 tcp_hdr->th_sport = inp->inp_lport; 458 tcp_hdr->th_dport = inp->inp_fport; 459 tcp_hdr->th_seq = 0; 460 tcp_hdr->th_ack = 0; 461 tcp_hdr->th_x2 = 0; 462 tcp_hdr->th_off = 5; 463 tcp_hdr->th_flags = 0; 464 tcp_hdr->th_win = 0; 465 tcp_hdr->th_urp = 0; 466 } 467 468 /* 469 * Create template to be used to send tcp packets on a connection. 470 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 471 * use for this function is in keepalives, which use tcp_respond. 472 */ 473 struct tcptemp * 474 tcp_maketemplate(struct tcpcb *tp) 475 { 476 struct tcptemp *tmp; 477 478 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL) 479 return (NULL); 480 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t); 481 return (tmp); 482 } 483 484 void 485 tcp_freetemplate(struct tcptemp *tmp) 486 { 487 mpipe_free(&tcptemp_mpipe, tmp); 488 } 489 490 /* 491 * Send a single message to the TCP at address specified by 492 * the given TCP/IP header. If m == NULL, then we make a copy 493 * of the tcpiphdr at ti and send directly to the addressed host. 494 * This is used to force keep alive messages out using the TCP 495 * template for a connection. If flags are given then we send 496 * a message back to the TCP which originated the * segment ti, 497 * and discard the mbuf containing it and any other attached mbufs. 498 * 499 * In any case the ack and sequence number of the transmitted 500 * segment are as specified by the parameters. 501 * 502 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 503 */ 504 void 505 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 506 tcp_seq ack, tcp_seq seq, int flags) 507 { 508 int tlen; 509 int win = 0; 510 struct route *ro = NULL; 511 struct route sro; 512 struct ip *ip = ipgen; 513 struct tcphdr *nth; 514 int ipflags = 0; 515 struct route_in6 *ro6 = NULL; 516 struct route_in6 sro6; 517 struct ip6_hdr *ip6 = ipgen; 518 #ifdef INET6 519 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6); 520 #else 521 const boolean_t isipv6 = FALSE; 522 #endif 523 524 if (tp != NULL) { 525 if (!(flags & TH_RST)) { 526 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 527 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 528 win = (long)TCP_MAXWIN << tp->rcv_scale; 529 } 530 if (isipv6) 531 ro6 = &tp->t_inpcb->in6p_route; 532 else 533 ro = &tp->t_inpcb->inp_route; 534 } else { 535 if (isipv6) { 536 ro6 = &sro6; 537 bzero(ro6, sizeof *ro6); 538 } else { 539 ro = &sro; 540 bzero(ro, sizeof *ro); 541 } 542 } 543 if (m == NULL) { 544 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 545 if (m == NULL) 546 return; 547 tlen = 0; 548 m->m_data += max_linkhdr; 549 if (isipv6) { 550 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr)); 551 ip6 = mtod(m, struct ip6_hdr *); 552 nth = (struct tcphdr *)(ip6 + 1); 553 } else { 554 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); 555 ip = mtod(m, struct ip *); 556 nth = (struct tcphdr *)(ip + 1); 557 } 558 bcopy(th, nth, sizeof(struct tcphdr)); 559 flags = TH_ACK; 560 } else { 561 m_freem(m->m_next); 562 m->m_next = NULL; 563 m->m_data = (caddr_t)ipgen; 564 /* m_len is set later */ 565 tlen = 0; 566 #define xchg(a, b, type) { type t; t = a; a = b; b = t; } 567 if (isipv6) { 568 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 569 nth = (struct tcphdr *)(ip6 + 1); 570 } else { 571 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 572 nth = (struct tcphdr *)(ip + 1); 573 } 574 if (th != nth) { 575 /* 576 * this is usually a case when an extension header 577 * exists between the IPv6 header and the 578 * TCP header. 579 */ 580 nth->th_sport = th->th_sport; 581 nth->th_dport = th->th_dport; 582 } 583 xchg(nth->th_dport, nth->th_sport, n_short); 584 #undef xchg 585 } 586 if (isipv6) { 587 ip6->ip6_flow = 0; 588 ip6->ip6_vfc = IPV6_VERSION; 589 ip6->ip6_nxt = IPPROTO_TCP; 590 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen)); 591 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 592 } else { 593 tlen += sizeof(struct tcpiphdr); 594 ip->ip_len = tlen; 595 ip->ip_ttl = ip_defttl; 596 } 597 m->m_len = tlen; 598 m->m_pkthdr.len = tlen; 599 m->m_pkthdr.rcvif = (struct ifnet *) NULL; 600 nth->th_seq = htonl(seq); 601 nth->th_ack = htonl(ack); 602 nth->th_x2 = 0; 603 nth->th_off = sizeof(struct tcphdr) >> 2; 604 nth->th_flags = flags; 605 if (tp != NULL) 606 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 607 else 608 nth->th_win = htons((u_short)win); 609 nth->th_urp = 0; 610 if (isipv6) { 611 nth->th_sum = 0; 612 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 613 sizeof(struct ip6_hdr), 614 tlen - sizeof(struct ip6_hdr)); 615 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 616 (ro6 && ro6->ro_rt) ? 617 ro6->ro_rt->rt_ifp : NULL); 618 } else { 619 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 620 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 621 m->m_pkthdr.csum_flags = CSUM_TCP; 622 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 623 } 624 #ifdef TCPDEBUG 625 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 626 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 627 #endif 628 if (isipv6) { 629 ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 630 tp ? tp->t_inpcb : NULL); 631 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) { 632 RTFREE(ro6->ro_rt); 633 ro6->ro_rt = NULL; 634 } 635 } else { 636 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 637 if ((ro == &sro) && (ro->ro_rt != NULL)) { 638 RTFREE(ro->ro_rt); 639 ro->ro_rt = NULL; 640 } 641 } 642 } 643 644 /* 645 * Create a new TCP control block, making an 646 * empty reassembly queue and hooking it to the argument 647 * protocol control block. The `inp' parameter must have 648 * come from the zone allocator set up in tcp_init(). 649 */ 650 struct tcpcb * 651 tcp_newtcpcb(struct inpcb *inp) 652 { 653 struct inp_tp *it; 654 struct tcpcb *tp; 655 #ifdef INET6 656 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 657 #else 658 const boolean_t isipv6 = FALSE; 659 #endif 660 661 it = (struct inp_tp *)inp; 662 tp = &it->tcb; 663 bzero(tp, sizeof(struct tcpcb)); 664 LIST_INIT(&tp->t_segq); 665 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt; 666 667 /* Set up our timeouts. */ 668 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt); 669 callout_init(tp->tt_persist = &it->inp_tp_persist); 670 callout_init(tp->tt_keep = &it->inp_tp_keep); 671 callout_init(tp->tt_2msl = &it->inp_tp_2msl); 672 callout_init(tp->tt_delack = &it->inp_tp_delack); 673 674 if (tcp_do_rfc1323) 675 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP); 676 if (tcp_do_rfc1644) 677 tp->t_flags |= TF_REQ_CC; 678 tp->t_inpcb = inp; /* XXX */ 679 tp->t_state = TCPS_CLOSED; 680 /* 681 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 682 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 683 * reasonable initial retransmit time. 684 */ 685 tp->t_srtt = TCPTV_SRTTBASE; 686 tp->t_rttvar = 687 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 688 tp->t_rttmin = tcp_rexmit_min; 689 tp->t_rxtcur = TCPTV_RTOBASE; 690 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 691 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 692 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 693 tp->t_rcvtime = ticks; 694 /* 695 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 696 * because the socket may be bound to an IPv6 wildcard address, 697 * which may match an IPv4-mapped IPv6 address. 698 */ 699 inp->inp_ip_ttl = ip_defttl; 700 inp->inp_ppcb = tp; 701 tcp_sack_tcpcb_init(tp); 702 return (tp); /* XXX */ 703 } 704 705 /* 706 * Drop a TCP connection, reporting the specified error. 707 * If connection is synchronized, then send a RST to peer. 708 */ 709 struct tcpcb * 710 tcp_drop(struct tcpcb *tp, int errno) 711 { 712 struct socket *so = tp->t_inpcb->inp_socket; 713 714 if (TCPS_HAVERCVDSYN(tp->t_state)) { 715 tp->t_state = TCPS_CLOSED; 716 tcp_output(tp); 717 tcpstat.tcps_drops++; 718 } else 719 tcpstat.tcps_conndrops++; 720 if (errno == ETIMEDOUT && tp->t_softerror) 721 errno = tp->t_softerror; 722 so->so_error = errno; 723 return (tcp_close(tp)); 724 } 725 726 #ifdef SMP 727 728 struct netmsg_remwildcard { 729 struct lwkt_msg nm_lmsg; 730 struct inpcb *nm_inp; 731 struct inpcbinfo *nm_pcbinfo; 732 #if defined(INET6) 733 int nm_isinet6; 734 #else 735 int nm_unused01; 736 #endif 737 }; 738 739 /* 740 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the 741 * inp can be detached. We do this by cycling through the cpus, ending up 742 * on the cpu controlling the inp last and then doing the disconnect. 743 */ 744 static int 745 in_pcbremwildcardhash_handler(struct lwkt_msg *msg0) 746 { 747 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0; 748 int cpu; 749 750 cpu = msg->nm_pcbinfo->cpu; 751 752 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) { 753 /* note: detach removes any wildcard hash entry */ 754 #ifdef INET6 755 if (msg->nm_isinet6) 756 in6_pcbdetach(msg->nm_inp); 757 else 758 #endif 759 in_pcbdetach(msg->nm_inp); 760 lwkt_replymsg(&msg->nm_lmsg, 0); 761 } else { 762 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo); 763 cpu = (cpu + 1) % ncpus2; 764 msg->nm_pcbinfo = &tcbinfo[cpu]; 765 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_lmsg); 766 } 767 return (EASYNC); 768 } 769 770 #endif 771 772 /* 773 * Close a TCP control block: 774 * discard all space held by the tcp 775 * discard internet protocol block 776 * wake up any sleepers 777 */ 778 struct tcpcb * 779 tcp_close(struct tcpcb *tp) 780 { 781 struct tseg_qent *q; 782 struct inpcb *inp = tp->t_inpcb; 783 struct socket *so = inp->inp_socket; 784 struct rtentry *rt; 785 boolean_t dosavessthresh; 786 #ifdef SMP 787 int cpu; 788 #endif 789 #ifdef INET6 790 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 791 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0); 792 #else 793 const boolean_t isipv6 = FALSE; 794 #endif 795 796 /* 797 * The tp is not instantly destroyed in the wildcard case. Setting 798 * the state to TCPS_TERMINATING will prevent the TCP stack from 799 * messing with it, though it should be noted that this change may 800 * not take effect on other cpus until we have chained the wildcard 801 * hash removal. 802 * 803 * XXX we currently depend on the BGL to synchronize the tp->t_state 804 * update and prevent other tcp protocol threads from accepting new 805 * connections on the listen socket we might be trying to close down. 806 */ 807 KKASSERT(tp->t_state != TCPS_TERMINATING); 808 tp->t_state = TCPS_TERMINATING; 809 810 /* 811 * Make sure that all of our timers are stopped before we 812 * delete the PCB. 813 */ 814 callout_stop(tp->tt_rexmt); 815 callout_stop(tp->tt_persist); 816 callout_stop(tp->tt_keep); 817 callout_stop(tp->tt_2msl); 818 callout_stop(tp->tt_delack); 819 820 if (tp->t_flags & TF_ONOUTPUTQ) { 821 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid); 822 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq); 823 tp->t_flags &= ~TF_ONOUTPUTQ; 824 } 825 826 /* 827 * If we got enough samples through the srtt filter, 828 * save the rtt and rttvar in the routing entry. 829 * 'Enough' is arbitrarily defined as the 16 samples. 830 * 16 samples is enough for the srtt filter to converge 831 * to within 5% of the correct value; fewer samples and 832 * we could save a very bogus rtt. 833 * 834 * Don't update the default route's characteristics and don't 835 * update anything that the user "locked". 836 */ 837 if (tp->t_rttupdated >= 16) { 838 u_long i = 0; 839 840 if (isipv6) { 841 struct sockaddr_in6 *sin6; 842 843 if ((rt = inp->in6p_route.ro_rt) == NULL) 844 goto no_valid_rt; 845 sin6 = (struct sockaddr_in6 *)rt_key(rt); 846 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 847 goto no_valid_rt; 848 } else 849 if ((rt = inp->inp_route.ro_rt) == NULL || 850 ((struct sockaddr_in *)rt_key(rt))-> 851 sin_addr.s_addr == INADDR_ANY) 852 goto no_valid_rt; 853 854 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) { 855 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 856 if (rt->rt_rmx.rmx_rtt && i) 857 /* 858 * filter this update to half the old & half 859 * the new values, converting scale. 860 * See route.h and tcp_var.h for a 861 * description of the scaling constants. 862 */ 863 rt->rt_rmx.rmx_rtt = 864 (rt->rt_rmx.rmx_rtt + i) / 2; 865 else 866 rt->rt_rmx.rmx_rtt = i; 867 tcpstat.tcps_cachedrtt++; 868 } 869 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) { 870 i = tp->t_rttvar * 871 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 872 if (rt->rt_rmx.rmx_rttvar && i) 873 rt->rt_rmx.rmx_rttvar = 874 (rt->rt_rmx.rmx_rttvar + i) / 2; 875 else 876 rt->rt_rmx.rmx_rttvar = i; 877 tcpstat.tcps_cachedrttvar++; 878 } 879 /* 880 * The old comment here said: 881 * update the pipelimit (ssthresh) if it has been updated 882 * already or if a pipesize was specified & the threshhold 883 * got below half the pipesize. I.e., wait for bad news 884 * before we start updating, then update on both good 885 * and bad news. 886 * 887 * But we want to save the ssthresh even if no pipesize is 888 * specified explicitly in the route, because such 889 * connections still have an implicit pipesize specified 890 * by the global tcp_sendspace. In the absence of a reliable 891 * way to calculate the pipesize, it will have to do. 892 */ 893 i = tp->snd_ssthresh; 894 if (rt->rt_rmx.rmx_sendpipe != 0) 895 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2); 896 else 897 dosavessthresh = (i < so->so_snd.sb_hiwat/2); 898 if (dosavessthresh || 899 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) && 900 (rt->rt_rmx.rmx_ssthresh != 0))) { 901 /* 902 * convert the limit from user data bytes to 903 * packets then to packet data bytes. 904 */ 905 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 906 if (i < 2) 907 i = 2; 908 i *= tp->t_maxseg + 909 (isipv6 ? 910 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 911 sizeof(struct tcpiphdr)); 912 if (rt->rt_rmx.rmx_ssthresh) 913 rt->rt_rmx.rmx_ssthresh = 914 (rt->rt_rmx.rmx_ssthresh + i) / 2; 915 else 916 rt->rt_rmx.rmx_ssthresh = i; 917 tcpstat.tcps_cachedssthresh++; 918 } 919 } 920 921 no_valid_rt: 922 /* free the reassembly queue, if any */ 923 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 924 LIST_REMOVE(q, tqe_q); 925 m_freem(q->tqe_m); 926 FREE(q, M_TSEGQ); 927 tcp_reass_qsize--; 928 } 929 /* throw away SACK blocks in scoreboard*/ 930 if (TCP_DO_SACK(tp)) 931 tcp_sack_cleanup(&tp->scb); 932 933 inp->inp_ppcb = NULL; 934 soisdisconnected(so); 935 /* 936 * Discard the inp. In the SMP case a wildcard inp's hash (created 937 * by a listen socket or an INADDR_ANY udp socket) is replicated 938 * for each protocol thread and must be removed in the context of 939 * that thread. This is accomplished by chaining the message 940 * through the cpus. 941 * 942 * If the inp is not wildcarded we simply detach, which will remove 943 * the any hashes still present for this inp. 944 */ 945 #ifdef SMP 946 if (inp->inp_flags & INP_WILDCARD_MP) { 947 struct netmsg_remwildcard *msg; 948 949 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2; 950 msg = malloc(sizeof(struct netmsg_remwildcard), 951 M_LWKTMSG, M_INTWAIT); 952 lwkt_initmsg(&msg->nm_lmsg, &netisr_afree_rport, 0, 953 lwkt_cmd_func(in_pcbremwildcardhash_handler), 954 lwkt_cmd_op_none); 955 #ifdef INET6 956 msg->nm_isinet6 = isafinet6; 957 #endif 958 msg->nm_inp = inp; 959 msg->nm_pcbinfo = &tcbinfo[cpu]; 960 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_lmsg); 961 } else 962 #endif 963 { 964 /* note: detach removes any wildcard hash entry */ 965 #ifdef INET6 966 if (isafinet6) 967 in6_pcbdetach(inp); 968 else 969 #endif 970 in_pcbdetach(inp); 971 } 972 tcpstat.tcps_closed++; 973 return (NULL); 974 } 975 976 static __inline void 977 tcp_drain_oncpu(struct inpcbhead *head) 978 { 979 struct inpcb *inpb; 980 struct tcpcb *tcpb; 981 struct tseg_qent *te; 982 983 LIST_FOREACH(inpb, head, inp_list) { 984 if (inpb->inp_flags & INP_PLACEMARKER) 985 continue; 986 if ((tcpb = intotcpcb(inpb))) { 987 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) { 988 LIST_REMOVE(te, tqe_q); 989 m_freem(te->tqe_m); 990 FREE(te, M_TSEGQ); 991 tcp_reass_qsize--; 992 } 993 } 994 } 995 } 996 997 #ifdef SMP 998 struct netmsg_tcp_drain { 999 struct lwkt_msg nm_lmsg; 1000 struct inpcbhead *nm_head; 1001 }; 1002 1003 static int 1004 tcp_drain_handler(lwkt_msg_t lmsg) 1005 { 1006 struct netmsg_tcp_drain *nm = (void *)lmsg; 1007 1008 tcp_drain_oncpu(nm->nm_head); 1009 lwkt_replymsg(lmsg, 0); 1010 return(EASYNC); 1011 } 1012 #endif 1013 1014 void 1015 tcp_drain() 1016 { 1017 #ifdef SMP 1018 int cpu; 1019 #endif 1020 1021 if (!do_tcpdrain) 1022 return; 1023 1024 /* 1025 * Walk the tcpbs, if existing, and flush the reassembly queue, 1026 * if there is one... 1027 * XXX: The "Net/3" implementation doesn't imply that the TCP 1028 * reassembly queue should be flushed, but in a situation 1029 * where we're really low on mbufs, this is potentially 1030 * useful. 1031 */ 1032 #ifdef SMP 1033 for (cpu = 0; cpu < ncpus2; cpu++) { 1034 struct netmsg_tcp_drain *msg; 1035 1036 if (cpu == mycpu->gd_cpuid) { 1037 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead); 1038 } else { 1039 msg = malloc(sizeof(struct netmsg_tcp_drain), 1040 M_LWKTMSG, M_NOWAIT); 1041 if (msg == NULL) 1042 continue; 1043 lwkt_initmsg(&msg->nm_lmsg, &netisr_afree_rport, 0, 1044 lwkt_cmd_func(tcp_drain_handler), 1045 lwkt_cmd_op_none); 1046 msg->nm_head = &tcbinfo[cpu].pcblisthead; 1047 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_lmsg); 1048 } 1049 } 1050 #else 1051 tcp_drain_oncpu(&tcbinfo[0].pcblisthead); 1052 #endif 1053 } 1054 1055 /* 1056 * Notify a tcp user of an asynchronous error; 1057 * store error as soft error, but wake up user 1058 * (for now, won't do anything until can select for soft error). 1059 * 1060 * Do not wake up user since there currently is no mechanism for 1061 * reporting soft errors (yet - a kqueue filter may be added). 1062 */ 1063 static void 1064 tcp_notify(struct inpcb *inp, int error) 1065 { 1066 struct tcpcb *tp = intotcpcb(inp); 1067 1068 /* 1069 * Ignore some errors if we are hooked up. 1070 * If connection hasn't completed, has retransmitted several times, 1071 * and receives a second error, give up now. This is better 1072 * than waiting a long time to establish a connection that 1073 * can never complete. 1074 */ 1075 if (tp->t_state == TCPS_ESTABLISHED && 1076 (error == EHOSTUNREACH || error == ENETUNREACH || 1077 error == EHOSTDOWN)) { 1078 return; 1079 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1080 tp->t_softerror) 1081 tcp_drop(tp, error); 1082 else 1083 tp->t_softerror = error; 1084 #if 0 1085 wakeup(&so->so_timeo); 1086 sorwakeup(so); 1087 sowwakeup(so); 1088 #endif 1089 } 1090 1091 static int 1092 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1093 { 1094 int error, i, n; 1095 struct inpcb *marker; 1096 struct inpcb *inp; 1097 inp_gen_t gencnt; 1098 globaldata_t gd; 1099 int origcpu, ccpu; 1100 1101 error = 0; 1102 n = 0; 1103 1104 /* 1105 * The process of preparing the TCB list is too time-consuming and 1106 * resource-intensive to repeat twice on every request. 1107 */ 1108 if (req->oldptr == NULL) { 1109 for (ccpu = 0; ccpu < ncpus; ++ccpu) { 1110 gd = globaldata_find(ccpu); 1111 n += tcbinfo[gd->gd_cpuid].ipi_count; 1112 } 1113 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb); 1114 return (0); 1115 } 1116 1117 if (req->newptr != NULL) 1118 return (EPERM); 1119 1120 marker = malloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1121 marker->inp_flags |= INP_PLACEMARKER; 1122 1123 /* 1124 * OK, now we're committed to doing something. Run the inpcb list 1125 * for each cpu in the system and construct the output. Use a 1126 * list placemarker to deal with list changes occuring during 1127 * copyout blockages (but otherwise depend on being on the correct 1128 * cpu to avoid races). 1129 */ 1130 origcpu = mycpu->gd_cpuid; 1131 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) { 1132 globaldata_t rgd; 1133 caddr_t inp_ppcb; 1134 struct xtcpcb xt; 1135 int cpu_id; 1136 1137 cpu_id = (origcpu + ccpu) % ncpus; 1138 if ((smp_active_mask & (1 << cpu_id)) == 0) 1139 continue; 1140 rgd = globaldata_find(cpu_id); 1141 lwkt_setcpu_self(rgd); 1142 1143 gencnt = tcbinfo[cpu_id].ipi_gencnt; 1144 n = tcbinfo[cpu_id].ipi_count; 1145 1146 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list); 1147 i = 0; 1148 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) { 1149 /* 1150 * process a snapshot of pcbs, ignoring placemarkers 1151 * and using our own to allow SYSCTL_OUT to block. 1152 */ 1153 LIST_REMOVE(marker, inp_list); 1154 LIST_INSERT_AFTER(inp, marker, inp_list); 1155 1156 if (inp->inp_flags & INP_PLACEMARKER) 1157 continue; 1158 if (inp->inp_gencnt > gencnt) 1159 continue; 1160 if (prison_xinpcb(req->td, inp)) 1161 continue; 1162 1163 xt.xt_len = sizeof xt; 1164 bcopy(inp, &xt.xt_inp, sizeof *inp); 1165 inp_ppcb = inp->inp_ppcb; 1166 if (inp_ppcb != NULL) 1167 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1168 else 1169 bzero(&xt.xt_tp, sizeof xt.xt_tp); 1170 if (inp->inp_socket) 1171 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1172 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0) 1173 break; 1174 ++i; 1175 } 1176 LIST_REMOVE(marker, inp_list); 1177 if (error == 0 && i < n) { 1178 bzero(&xt, sizeof xt); 1179 xt.xt_len = sizeof xt; 1180 while (i < n) { 1181 error = SYSCTL_OUT(req, &xt, sizeof xt); 1182 if (error) 1183 break; 1184 ++i; 1185 } 1186 } 1187 } 1188 1189 /* 1190 * Make sure we are on the same cpu we were on originally, since 1191 * higher level callers expect this. Also don't pollute caches with 1192 * migrated userland data by (eventually) returning to userland 1193 * on a different cpu. 1194 */ 1195 lwkt_setcpu_self(globaldata_find(origcpu)); 1196 free(marker, M_TEMP); 1197 return (error); 1198 } 1199 1200 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1201 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1202 1203 static int 1204 tcp_getcred(SYSCTL_HANDLER_ARGS) 1205 { 1206 struct sockaddr_in addrs[2]; 1207 struct inpcb *inp; 1208 int cpu; 1209 int error, s; 1210 1211 error = suser(req->td); 1212 if (error != 0) 1213 return (error); 1214 error = SYSCTL_IN(req, addrs, sizeof addrs); 1215 if (error != 0) 1216 return (error); 1217 s = splnet(); 1218 1219 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1220 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1221 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1222 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1223 if (inp == NULL || inp->inp_socket == NULL) { 1224 error = ENOENT; 1225 goto out; 1226 } 1227 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1228 out: 1229 splx(s); 1230 return (error); 1231 } 1232 1233 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1234 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1235 1236 #ifdef INET6 1237 static int 1238 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1239 { 1240 struct sockaddr_in6 addrs[2]; 1241 struct inpcb *inp; 1242 int error, s; 1243 boolean_t mapped = FALSE; 1244 1245 error = suser(req->td); 1246 if (error != 0) 1247 return (error); 1248 error = SYSCTL_IN(req, addrs, sizeof addrs); 1249 if (error != 0) 1250 return (error); 1251 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1252 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1253 mapped = TRUE; 1254 else 1255 return (EINVAL); 1256 } 1257 s = splnet(); 1258 if (mapped) { 1259 inp = in_pcblookup_hash(&tcbinfo[0], 1260 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1261 addrs[1].sin6_port, 1262 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1263 addrs[0].sin6_port, 1264 0, NULL); 1265 } else { 1266 inp = in6_pcblookup_hash(&tcbinfo[0], 1267 &addrs[1].sin6_addr, addrs[1].sin6_port, 1268 &addrs[0].sin6_addr, addrs[0].sin6_port, 1269 0, NULL); 1270 } 1271 if (inp == NULL || inp->inp_socket == NULL) { 1272 error = ENOENT; 1273 goto out; 1274 } 1275 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1276 out: 1277 splx(s); 1278 return (error); 1279 } 1280 1281 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1282 0, 0, 1283 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1284 #endif 1285 1286 void 1287 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1288 { 1289 struct ip *ip = vip; 1290 struct tcphdr *th; 1291 struct in_addr faddr; 1292 struct inpcb *inp; 1293 struct tcpcb *tp; 1294 void (*notify)(struct inpcb *, int) = tcp_notify; 1295 tcp_seq icmpseq; 1296 int arg, cpu, s; 1297 1298 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) { 1299 return; 1300 } 1301 1302 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1303 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1304 return; 1305 1306 arg = inetctlerrmap[cmd]; 1307 if (cmd == PRC_QUENCH) { 1308 notify = tcp_quench; 1309 } else if (icmp_may_rst && 1310 (cmd == PRC_UNREACH_ADMIN_PROHIB || 1311 cmd == PRC_UNREACH_PORT || 1312 cmd == PRC_TIMXCEED_INTRANS) && 1313 ip != NULL) { 1314 notify = tcp_drop_syn_sent; 1315 } else if (cmd == PRC_MSGSIZE) { 1316 struct icmp *icmp = (struct icmp *) 1317 ((caddr_t)ip - offsetof(struct icmp, icmp_ip)); 1318 1319 arg = ntohs(icmp->icmp_nextmtu); 1320 notify = tcp_mtudisc; 1321 } else if (PRC_IS_REDIRECT(cmd)) { 1322 ip = NULL; 1323 notify = in_rtchange; 1324 } else if (cmd == PRC_HOSTDEAD) { 1325 ip = NULL; 1326 } 1327 1328 if (ip != NULL) { 1329 s = splnet(); 1330 th = (struct tcphdr *)((caddr_t)ip + 1331 (IP_VHL_HL(ip->ip_vhl) << 2)); 1332 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1333 ip->ip_src.s_addr, th->th_sport); 1334 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1335 ip->ip_src, th->th_sport, 0, NULL); 1336 if ((inp != NULL) && (inp->inp_socket != NULL)) { 1337 icmpseq = htonl(th->th_seq); 1338 tp = intotcpcb(inp); 1339 if (SEQ_GEQ(icmpseq, tp->snd_una) && 1340 SEQ_LT(icmpseq, tp->snd_max)) 1341 (*notify)(inp, arg); 1342 } else { 1343 struct in_conninfo inc; 1344 1345 inc.inc_fport = th->th_dport; 1346 inc.inc_lport = th->th_sport; 1347 inc.inc_faddr = faddr; 1348 inc.inc_laddr = ip->ip_src; 1349 #ifdef INET6 1350 inc.inc_isipv6 = 0; 1351 #endif 1352 syncache_unreach(&inc, th); 1353 } 1354 splx(s); 1355 } else { 1356 for (cpu = 0; cpu < ncpus2; cpu++) { 1357 in_pcbnotifyall(&tcbinfo[cpu].pcblisthead, faddr, arg, 1358 notify); 1359 } 1360 } 1361 } 1362 1363 #ifdef INET6 1364 void 1365 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1366 { 1367 struct tcphdr th; 1368 void (*notify) (struct inpcb *, int) = tcp_notify; 1369 struct ip6_hdr *ip6; 1370 struct mbuf *m; 1371 struct ip6ctlparam *ip6cp = NULL; 1372 const struct sockaddr_in6 *sa6_src = NULL; 1373 int off; 1374 struct tcp_portonly { 1375 u_int16_t th_sport; 1376 u_int16_t th_dport; 1377 } *thp; 1378 int arg; 1379 1380 if (sa->sa_family != AF_INET6 || 1381 sa->sa_len != sizeof(struct sockaddr_in6)) 1382 return; 1383 1384 arg = 0; 1385 if (cmd == PRC_QUENCH) 1386 notify = tcp_quench; 1387 else if (cmd == PRC_MSGSIZE) { 1388 struct ip6ctlparam *ip6cp = d; 1389 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6; 1390 1391 arg = ntohl(icmp6->icmp6_mtu); 1392 notify = tcp_mtudisc; 1393 } else if (!PRC_IS_REDIRECT(cmd) && 1394 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) { 1395 return; 1396 } 1397 1398 /* if the parameter is from icmp6, decode it. */ 1399 if (d != NULL) { 1400 ip6cp = (struct ip6ctlparam *)d; 1401 m = ip6cp->ip6c_m; 1402 ip6 = ip6cp->ip6c_ip6; 1403 off = ip6cp->ip6c_off; 1404 sa6_src = ip6cp->ip6c_src; 1405 } else { 1406 m = NULL; 1407 ip6 = NULL; 1408 off = 0; /* fool gcc */ 1409 sa6_src = &sa6_any; 1410 } 1411 1412 if (ip6 != NULL) { 1413 struct in_conninfo inc; 1414 /* 1415 * XXX: We assume that when IPV6 is non NULL, 1416 * M and OFF are valid. 1417 */ 1418 1419 /* check if we can safely examine src and dst ports */ 1420 if (m->m_pkthdr.len < off + sizeof *thp) 1421 return; 1422 1423 bzero(&th, sizeof th); 1424 m_copydata(m, off, sizeof *thp, (caddr_t)&th); 1425 1426 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport, 1427 (struct sockaddr *)ip6cp->ip6c_src, 1428 th.th_sport, cmd, arg, notify); 1429 1430 inc.inc_fport = th.th_dport; 1431 inc.inc_lport = th.th_sport; 1432 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1433 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1434 inc.inc_isipv6 = 1; 1435 syncache_unreach(&inc, &th); 1436 } else 1437 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0, 1438 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify); 1439 } 1440 #endif 1441 1442 /* 1443 * Following is where TCP initial sequence number generation occurs. 1444 * 1445 * There are two places where we must use initial sequence numbers: 1446 * 1. In SYN-ACK packets. 1447 * 2. In SYN packets. 1448 * 1449 * All ISNs for SYN-ACK packets are generated by the syncache. See 1450 * tcp_syncache.c for details. 1451 * 1452 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1453 * depends on this property. In addition, these ISNs should be 1454 * unguessable so as to prevent connection hijacking. To satisfy 1455 * the requirements of this situation, the algorithm outlined in 1456 * RFC 1948 is used to generate sequence numbers. 1457 * 1458 * Implementation details: 1459 * 1460 * Time is based off the system timer, and is corrected so that it 1461 * increases by one megabyte per second. This allows for proper 1462 * recycling on high speed LANs while still leaving over an hour 1463 * before rollover. 1464 * 1465 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1466 * between seeding of isn_secret. This is normally set to zero, 1467 * as reseeding should not be necessary. 1468 * 1469 */ 1470 1471 #define ISN_BYTES_PER_SECOND 1048576 1472 1473 u_char isn_secret[32]; 1474 int isn_last_reseed; 1475 MD5_CTX isn_ctx; 1476 1477 tcp_seq 1478 tcp_new_isn(struct tcpcb *tp) 1479 { 1480 u_int32_t md5_buffer[4]; 1481 tcp_seq new_isn; 1482 1483 /* Seed if this is the first use, reseed if requested. */ 1484 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1485 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1486 < (u_int)ticks))) { 1487 read_random_unlimited(&isn_secret, sizeof isn_secret); 1488 isn_last_reseed = ticks; 1489 } 1490 1491 /* Compute the md5 hash and return the ISN. */ 1492 MD5Init(&isn_ctx); 1493 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 1494 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 1495 #ifdef INET6 1496 if (tp->t_inpcb->inp_vflag & INP_IPV6) { 1497 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1498 sizeof(struct in6_addr)); 1499 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1500 sizeof(struct in6_addr)); 1501 } else 1502 #endif 1503 { 1504 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1505 sizeof(struct in_addr)); 1506 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1507 sizeof(struct in_addr)); 1508 } 1509 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1510 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1511 new_isn = (tcp_seq) md5_buffer[0]; 1512 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1513 return (new_isn); 1514 } 1515 1516 /* 1517 * When a source quench is received, close congestion window 1518 * to one segment. We will gradually open it again as we proceed. 1519 */ 1520 void 1521 tcp_quench(struct inpcb *inp, int errno) 1522 { 1523 struct tcpcb *tp = intotcpcb(inp); 1524 1525 if (tp != NULL) 1526 tp->snd_cwnd = tp->t_maxseg; 1527 } 1528 1529 /* 1530 * When a specific ICMP unreachable message is received and the 1531 * connection state is SYN-SENT, drop the connection. This behavior 1532 * is controlled by the icmp_may_rst sysctl. 1533 */ 1534 void 1535 tcp_drop_syn_sent(struct inpcb *inp, int errno) 1536 { 1537 struct tcpcb *tp = intotcpcb(inp); 1538 1539 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT)) 1540 tcp_drop(tp, errno); 1541 } 1542 1543 /* 1544 * When a `need fragmentation' ICMP is received, update our idea of the MSS 1545 * based on the new value in the route. Also nudge TCP to send something, 1546 * since we know the packet we just sent was dropped. 1547 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1548 */ 1549 void 1550 tcp_mtudisc(struct inpcb *inp, int mtu) 1551 { 1552 struct tcpcb *tp = intotcpcb(inp); 1553 struct rtentry *rt; 1554 struct socket *so = inp->inp_socket; 1555 int maxopd, mss; 1556 #ifdef INET6 1557 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0); 1558 #else 1559 const boolean_t isipv6 = FALSE; 1560 #endif 1561 1562 if (tp == NULL) 1563 return; 1564 1565 /* 1566 * If no MTU is provided in the ICMP message, use the 1567 * next lower likely value, as specified in RFC 1191. 1568 */ 1569 if (mtu == 0) { 1570 int oldmtu; 1571 1572 oldmtu = tp->t_maxopd + 1573 (isipv6 ? 1574 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1575 sizeof(struct tcpiphdr)); 1576 mtu = ip_next_mtu(oldmtu, 0); 1577 } 1578 1579 if (isipv6) 1580 rt = tcp_rtlookup6(&inp->inp_inc); 1581 else 1582 rt = tcp_rtlookup(&inp->inp_inc); 1583 if (rt != NULL) { 1584 struct rmxp_tao *taop = rmx_taop(rt->rt_rmx); 1585 1586 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu) 1587 mtu = rt->rt_rmx.rmx_mtu; 1588 1589 maxopd = mtu - 1590 (isipv6 ? 1591 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1592 sizeof(struct tcpiphdr)); 1593 1594 /* 1595 * XXX - The following conditional probably violates the TCP 1596 * spec. The problem is that, since we don't know the 1597 * other end's MSS, we are supposed to use a conservative 1598 * default. But, if we do that, then MTU discovery will 1599 * never actually take place, because the conservative 1600 * default is much less than the MTUs typically seen 1601 * on the Internet today. For the moment, we'll sweep 1602 * this under the carpet. 1603 * 1604 * The conservative default might not actually be a problem 1605 * if the only case this occurs is when sending an initial 1606 * SYN with options and data to a host we've never talked 1607 * to before. Then, they will reply with an MSS value which 1608 * will get recorded and the new parameters should get 1609 * recomputed. For Further Study. 1610 */ 1611 if (taop->tao_mssopt != 0 && taop->tao_mssopt < maxopd) 1612 maxopd = taop->tao_mssopt; 1613 } else 1614 maxopd = mtu - 1615 (isipv6 ? 1616 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1617 sizeof(struct tcpiphdr)); 1618 1619 if (tp->t_maxopd <= maxopd) 1620 return; 1621 tp->t_maxopd = maxopd; 1622 1623 mss = maxopd; 1624 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) == 1625 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1626 mss -= TCPOLEN_TSTAMP_APPA; 1627 1628 if ((tp->t_flags & (TF_REQ_CC | TF_RCVD_CC | TF_NOOPT)) == 1629 (TF_REQ_CC | TF_RCVD_CC)) 1630 mss -= TCPOLEN_CC_APPA; 1631 1632 /* round down to multiple of MCLBYTES */ 1633 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */ 1634 if (mss > MCLBYTES) 1635 mss &= ~(MCLBYTES - 1); 1636 #else 1637 if (mss > MCLBYTES) 1638 mss = (mss / MCLBYTES) * MCLBYTES; 1639 #endif 1640 1641 if (so->so_snd.sb_hiwat < mss) 1642 mss = so->so_snd.sb_hiwat; 1643 1644 tp->t_maxseg = mss; 1645 tp->t_rtttime = 0; 1646 tp->snd_nxt = tp->snd_una; 1647 tcp_output(tp); 1648 tcpstat.tcps_mturesent++; 1649 } 1650 1651 /* 1652 * Look-up the routing entry to the peer of this inpcb. If no route 1653 * is found and it cannot be allocated the return NULL. This routine 1654 * is called by TCP routines that access the rmx structure and by tcp_mss 1655 * to get the interface MTU. 1656 */ 1657 struct rtentry * 1658 tcp_rtlookup(struct in_conninfo *inc) 1659 { 1660 struct route *ro = &inc->inc_route; 1661 1662 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) { 1663 /* No route yet, so try to acquire one */ 1664 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1665 /* 1666 * unused portions of the structure MUST be zero'd 1667 * out because rtalloc() treats it as opaque data 1668 */ 1669 bzero(&ro->ro_dst, sizeof(struct sockaddr_in)); 1670 ro->ro_dst.sa_family = AF_INET; 1671 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1672 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1673 inc->inc_faddr; 1674 rtalloc(ro); 1675 } 1676 } 1677 return (ro->ro_rt); 1678 } 1679 1680 #ifdef INET6 1681 struct rtentry * 1682 tcp_rtlookup6(struct in_conninfo *inc) 1683 { 1684 struct route_in6 *ro6 = &inc->inc6_route; 1685 1686 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) { 1687 /* No route yet, so try to acquire one */ 1688 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1689 /* 1690 * unused portions of the structure MUST be zero'd 1691 * out because rtalloc() treats it as opaque data 1692 */ 1693 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6)); 1694 ro6->ro_dst.sin6_family = AF_INET6; 1695 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1696 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1697 rtalloc((struct route *)ro6); 1698 } 1699 } 1700 return (ro6->ro_rt); 1701 } 1702 #endif 1703 1704 #ifdef IPSEC 1705 /* compute ESP/AH header size for TCP, including outer IP header. */ 1706 size_t 1707 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1708 { 1709 struct inpcb *inp; 1710 struct mbuf *m; 1711 size_t hdrsiz; 1712 struct ip *ip; 1713 struct tcphdr *th; 1714 1715 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1716 return (0); 1717 MGETHDR(m, MB_DONTWAIT, MT_DATA); 1718 if (!m) 1719 return (0); 1720 1721 #ifdef INET6 1722 if (inp->inp_vflag & INP_IPV6) { 1723 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 1724 1725 th = (struct tcphdr *)(ip6 + 1); 1726 m->m_pkthdr.len = m->m_len = 1727 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1728 tcp_fillheaders(tp, ip6, th); 1729 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1730 } else 1731 #endif 1732 { 1733 ip = mtod(m, struct ip *); 1734 th = (struct tcphdr *)(ip + 1); 1735 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1736 tcp_fillheaders(tp, ip, th); 1737 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1738 } 1739 1740 m_free(m); 1741 return (hdrsiz); 1742 } 1743 #endif 1744 1745 /* 1746 * Return a pointer to the cached information about the remote host. 1747 * The cached information is stored in the protocol specific part of 1748 * the route metrics. 1749 */ 1750 struct rmxp_tao * 1751 tcp_gettaocache(struct in_conninfo *inc) 1752 { 1753 struct rtentry *rt; 1754 1755 #ifdef INET6 1756 if (inc->inc_isipv6) 1757 rt = tcp_rtlookup6(inc); 1758 else 1759 #endif 1760 rt = tcp_rtlookup(inc); 1761 1762 /* Make sure this is a host route and is up. */ 1763 if (rt == NULL || 1764 (rt->rt_flags & (RTF_UP | RTF_HOST)) != (RTF_UP | RTF_HOST)) 1765 return (NULL); 1766 1767 return (rmx_taop(rt->rt_rmx)); 1768 } 1769 1770 /* 1771 * Clear all the TAO cache entries, called from tcp_init. 1772 * 1773 * XXX 1774 * This routine is just an empty one, because we assume that the routing 1775 * routing tables are initialized at the same time when TCP, so there is 1776 * nothing in the cache left over. 1777 */ 1778 static void 1779 tcp_cleartaocache() 1780 { 1781 } 1782 1783 /* 1784 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1785 * 1786 * This code attempts to calculate the bandwidth-delay product as a 1787 * means of determining the optimal window size to maximize bandwidth, 1788 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1789 * routers. This code also does a fairly good job keeping RTTs in check 1790 * across slow links like modems. We implement an algorithm which is very 1791 * similar (but not meant to be) TCP/Vegas. The code operates on the 1792 * transmitter side of a TCP connection and so only effects the transmit 1793 * side of the connection. 1794 * 1795 * BACKGROUND: TCP makes no provision for the management of buffer space 1796 * at the end points or at the intermediate routers and switches. A TCP 1797 * stream, whether using NewReno or not, will eventually buffer as 1798 * many packets as it is able and the only reason this typically works is 1799 * due to the fairly small default buffers made available for a connection 1800 * (typicaly 16K or 32K). As machines use larger windows and/or window 1801 * scaling it is now fairly easy for even a single TCP connection to blow-out 1802 * all available buffer space not only on the local interface, but on 1803 * intermediate routers and switches as well. NewReno makes a misguided 1804 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1805 * then backing off, then steadily increasing the window again until another 1806 * failure occurs, ad-infinitum. This results in terrible oscillation that 1807 * is only made worse as network loads increase and the idea of intentionally 1808 * blowing out network buffers is, frankly, a terrible way to manage network 1809 * resources. 1810 * 1811 * It is far better to limit the transmit window prior to the failure 1812 * condition being achieved. There are two general ways to do this: First 1813 * you can 'scan' through different transmit window sizes and locate the 1814 * point where the RTT stops increasing, indicating that you have filled the 1815 * pipe, then scan backwards until you note that RTT stops decreasing, then 1816 * repeat ad-infinitum. This method works in principle but has severe 1817 * implementation issues due to RTT variances, timer granularity, and 1818 * instability in the algorithm which can lead to many false positives and 1819 * create oscillations as well as interact badly with other TCP streams 1820 * implementing the same algorithm. 1821 * 1822 * The second method is to limit the window to the bandwidth delay product 1823 * of the link. This is the method we implement. RTT variances and our 1824 * own manipulation of the congestion window, bwnd, can potentially 1825 * destabilize the algorithm. For this reason we have to stabilize the 1826 * elements used to calculate the window. We do this by using the minimum 1827 * observed RTT, the long term average of the observed bandwidth, and 1828 * by adding two segments worth of slop. It isn't perfect but it is able 1829 * to react to changing conditions and gives us a very stable basis on 1830 * which to extend the algorithm. 1831 */ 1832 void 1833 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1834 { 1835 u_long bw; 1836 u_long bwnd; 1837 int save_ticks; 1838 int delta_ticks; 1839 1840 /* 1841 * If inflight_enable is disabled in the middle of a tcp connection, 1842 * make sure snd_bwnd is effectively disabled. 1843 */ 1844 if (!tcp_inflight_enable) { 1845 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1846 tp->snd_bandwidth = 0; 1847 return; 1848 } 1849 1850 /* 1851 * Validate the delta time. If a connection is new or has been idle 1852 * a long time we have to reset the bandwidth calculator. 1853 */ 1854 save_ticks = ticks; 1855 delta_ticks = save_ticks - tp->t_bw_rtttime; 1856 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) { 1857 tp->t_bw_rtttime = ticks; 1858 tp->t_bw_rtseq = ack_seq; 1859 if (tp->snd_bandwidth == 0) 1860 tp->snd_bandwidth = tcp_inflight_min; 1861 return; 1862 } 1863 if (delta_ticks == 0) 1864 return; 1865 1866 /* 1867 * Sanity check, plus ignore pure window update acks. 1868 */ 1869 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0) 1870 return; 1871 1872 /* 1873 * Figure out the bandwidth. Due to the tick granularity this 1874 * is a very rough number and it MUST be averaged over a fairly 1875 * long period of time. XXX we need to take into account a link 1876 * that is not using all available bandwidth, but for now our 1877 * slop will ramp us up if this case occurs and the bandwidth later 1878 * increases. 1879 */ 1880 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks; 1881 tp->t_bw_rtttime = save_ticks; 1882 tp->t_bw_rtseq = ack_seq; 1883 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1884 1885 tp->snd_bandwidth = bw; 1886 1887 /* 1888 * Calculate the semi-static bandwidth delay product, plus two maximal 1889 * segments. The additional slop puts us squarely in the sweet 1890 * spot and also handles the bandwidth run-up case. Without the 1891 * slop we could be locking ourselves into a lower bandwidth. 1892 * 1893 * Situations Handled: 1894 * (1) Prevents over-queueing of packets on LANs, especially on 1895 * high speed LANs, allowing larger TCP buffers to be 1896 * specified, and also does a good job preventing 1897 * over-queueing of packets over choke points like modems 1898 * (at least for the transmit side). 1899 * 1900 * (2) Is able to handle changing network loads (bandwidth 1901 * drops so bwnd drops, bandwidth increases so bwnd 1902 * increases). 1903 * 1904 * (3) Theoretically should stabilize in the face of multiple 1905 * connections implementing the same algorithm (this may need 1906 * a little work). 1907 * 1908 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1909 * be adjusted with a sysctl but typically only needs to be on 1910 * very slow connections. A value no smaller then 5 should 1911 * be used, but only reduce this default if you have no other 1912 * choice. 1913 */ 1914 1915 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1916 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + 1917 tcp_inflight_stab * (int)tp->t_maxseg / 10; 1918 #undef USERTT 1919 1920 if (tcp_inflight_debug > 0) { 1921 static int ltime; 1922 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1923 ltime = ticks; 1924 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1925 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd); 1926 } 1927 } 1928 if ((long)bwnd < tcp_inflight_min) 1929 bwnd = tcp_inflight_min; 1930 if (bwnd > tcp_inflight_max) 1931 bwnd = tcp_inflight_max; 1932 if ((long)bwnd < tp->t_maxseg * 2) 1933 bwnd = tp->t_maxseg * 2; 1934 tp->snd_bwnd = bwnd; 1935 } 1936