1 /* 2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved. 3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved. 4 * 5 * This code is derived from software contributed to The DragonFly Project 6 * by Jeffrey M. Hsu. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of The DragonFly Project nor the names of its 17 * contributors may be used to endorse or promote products derived 18 * from this software without specific, prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 36 * The Regents of the University of California. All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. All advertising materials mentioning features or use of this software 47 * must display the following acknowledgement: 48 * This product includes software developed by the University of 49 * California, Berkeley and its contributors. 50 * 4. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 67 * $FreeBSD: src/sys/netinet/tcp_subr.c,v 1.73.2.31 2003/01/24 05:11:34 sam Exp $ 68 * $DragonFly: src/sys/netinet/tcp_subr.c,v 1.60 2008/08/15 21:37:16 nth Exp $ 69 */ 70 71 #include "opt_compat.h" 72 #include "opt_inet6.h" 73 #include "opt_ipsec.h" 74 #include "opt_tcpdebug.h" 75 76 #include <sys/param.h> 77 #include <sys/systm.h> 78 #include <sys/callout.h> 79 #include <sys/kernel.h> 80 #include <sys/sysctl.h> 81 #include <sys/malloc.h> 82 #include <sys/mpipe.h> 83 #include <sys/mbuf.h> 84 #ifdef INET6 85 #include <sys/domain.h> 86 #endif 87 #include <sys/proc.h> 88 #include <sys/socket.h> 89 #include <sys/socketvar.h> 90 #include <sys/protosw.h> 91 #include <sys/random.h> 92 #include <sys/in_cksum.h> 93 #include <sys/ktr.h> 94 95 #include <vm/vm_zone.h> 96 97 #include <net/route.h> 98 #include <net/if.h> 99 #include <net/netisr.h> 100 101 #define _IP_VHL 102 #include <netinet/in.h> 103 #include <netinet/in_systm.h> 104 #include <netinet/ip.h> 105 #include <netinet/ip6.h> 106 #include <netinet/in_pcb.h> 107 #include <netinet6/in6_pcb.h> 108 #include <netinet/in_var.h> 109 #include <netinet/ip_var.h> 110 #include <netinet6/ip6_var.h> 111 #include <netinet/ip_icmp.h> 112 #ifdef INET6 113 #include <netinet/icmp6.h> 114 #endif 115 #include <netinet/tcp.h> 116 #include <netinet/tcp_fsm.h> 117 #include <netinet/tcp_seq.h> 118 #include <netinet/tcp_timer.h> 119 #include <netinet/tcp_var.h> 120 #include <netinet6/tcp6_var.h> 121 #include <netinet/tcpip.h> 122 #ifdef TCPDEBUG 123 #include <netinet/tcp_debug.h> 124 #endif 125 #include <netinet6/ip6protosw.h> 126 127 #ifdef IPSEC 128 #include <netinet6/ipsec.h> 129 #ifdef INET6 130 #include <netinet6/ipsec6.h> 131 #endif 132 #endif 133 134 #ifdef FAST_IPSEC 135 #include <netproto/ipsec/ipsec.h> 136 #ifdef INET6 137 #include <netproto/ipsec/ipsec6.h> 138 #endif 139 #define IPSEC 140 #endif 141 142 #include <sys/md5.h> 143 #include <sys/msgport2.h> 144 #include <machine/smp.h> 145 146 #include <net/netmsg2.h> 147 148 #if !defined(KTR_TCP) 149 #define KTR_TCP KTR_ALL 150 #endif 151 KTR_INFO_MASTER(tcp); 152 KTR_INFO(KTR_TCP, tcp, rxmsg, 0, "tcp getmsg", 0); 153 KTR_INFO(KTR_TCP, tcp, wait, 1, "tcp waitmsg", 0); 154 KTR_INFO(KTR_TCP, tcp, delayed, 2, "tcp execute delayed ops", 0); 155 #define logtcp(name) KTR_LOG(tcp_ ## name) 156 157 struct inpcbinfo tcbinfo[MAXCPU]; 158 struct tcpcbackqhead tcpcbackq[MAXCPU]; 159 160 int tcp_mssdflt = TCP_MSS; 161 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 162 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size"); 163 164 #ifdef INET6 165 int tcp_v6mssdflt = TCP6_MSS; 166 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW, 167 &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6"); 168 #endif 169 170 #if 0 171 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 172 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 173 &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time"); 174 #endif 175 176 int tcp_do_rfc1323 = 1; 177 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 178 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions"); 179 180 int tcp_do_rfc1644 = 0; 181 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 182 &tcp_do_rfc1644, 0, "Enable rfc1644 (TTCP) extensions"); 183 184 static int tcp_tcbhashsize = 0; 185 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 186 &tcp_tcbhashsize, 0, "Size of TCP control block hashtable"); 187 188 static int do_tcpdrain = 1; 189 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 190 "Enable tcp_drain routine for extra help when low on mbufs"); 191 192 /* XXX JH */ 193 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 194 &tcbinfo[0].ipi_count, 0, "Number of active PCBs"); 195 196 static int icmp_may_rst = 1; 197 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 198 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 199 200 static int tcp_isn_reseed_interval = 0; 201 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 202 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 203 204 /* 205 * TCP bandwidth limiting sysctls. Note that the default lower bound of 206 * 1024 exists only for debugging. A good production default would be 207 * something like 6100. 208 */ 209 static int tcp_inflight_enable = 0; 210 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW, 211 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 212 213 static int tcp_inflight_debug = 0; 214 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW, 215 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 216 217 static int tcp_inflight_min = 6144; 218 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW, 219 &tcp_inflight_min, 0, "Lower bound for TCP inflight window"); 220 221 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 222 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW, 223 &tcp_inflight_max, 0, "Upper bound for TCP inflight window"); 224 225 static int tcp_inflight_stab = 20; 226 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW, 227 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 2 packets)"); 228 229 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives"); 230 static struct malloc_pipe tcptemp_mpipe; 231 232 static void tcp_willblock(void); 233 static void tcp_cleartaocache (void); 234 static void tcp_notify (struct inpcb *, int); 235 236 struct tcp_stats tcpstats_percpu[MAXCPU]; 237 #ifdef SMP 238 static int 239 sysctl_tcpstats(SYSCTL_HANDLER_ARGS) 240 { 241 int cpu, error = 0; 242 243 for (cpu = 0; cpu < ncpus; ++cpu) { 244 if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu], 245 sizeof(struct tcp_stats)))) 246 break; 247 if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu], 248 sizeof(struct tcp_stats)))) 249 break; 250 } 251 252 return (error); 253 } 254 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 255 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics"); 256 #else 257 SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW, 258 &tcpstat, tcp_stats, "TCP statistics"); 259 #endif 260 261 /* 262 * Target size of TCP PCB hash tables. Must be a power of two. 263 * 264 * Note that this can be overridden by the kernel environment 265 * variable net.inet.tcp.tcbhashsize 266 */ 267 #ifndef TCBHASHSIZE 268 #define TCBHASHSIZE 512 269 #endif 270 271 /* 272 * This is the actual shape of what we allocate using the zone 273 * allocator. Doing it this way allows us to protect both structures 274 * using the same generation count, and also eliminates the overhead 275 * of allocating tcpcbs separately. By hiding the structure here, 276 * we avoid changing most of the rest of the code (although it needs 277 * to be changed, eventually, for greater efficiency). 278 */ 279 #define ALIGNMENT 32 280 #define ALIGNM1 (ALIGNMENT - 1) 281 struct inp_tp { 282 union { 283 struct inpcb inp; 284 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 285 } inp_tp_u; 286 struct tcpcb tcb; 287 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl; 288 struct callout inp_tp_delack; 289 }; 290 #undef ALIGNMENT 291 #undef ALIGNM1 292 293 /* 294 * Tcp initialization 295 */ 296 void 297 tcp_init(void) 298 { 299 struct inpcbporthead *porthashbase; 300 u_long porthashmask; 301 struct vm_zone *ipi_zone; 302 int hashsize = TCBHASHSIZE; 303 int cpu; 304 305 /* 306 * note: tcptemp is used for keepalives, and it is ok for an 307 * allocation to fail so do not specify MPF_INT. 308 */ 309 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp), 310 25, -1, 0, NULL); 311 312 tcp_ccgen = 1; 313 tcp_cleartaocache(); 314 315 tcp_delacktime = TCPTV_DELACK; 316 tcp_keepinit = TCPTV_KEEP_INIT; 317 tcp_keepidle = TCPTV_KEEP_IDLE; 318 tcp_keepintvl = TCPTV_KEEPINTVL; 319 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 320 tcp_msl = TCPTV_MSL; 321 tcp_rexmit_min = TCPTV_MIN; 322 tcp_rexmit_slop = TCPTV_CPU_VAR; 323 324 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 325 if (!powerof2(hashsize)) { 326 kprintf("WARNING: TCB hash size not a power of 2\n"); 327 hashsize = 512; /* safe default */ 328 } 329 tcp_tcbhashsize = hashsize; 330 porthashbase = hashinit(hashsize, M_PCB, &porthashmask); 331 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 332 ZONE_INTERRUPT, 0); 333 334 for (cpu = 0; cpu < ncpus2; cpu++) { 335 in_pcbinfo_init(&tcbinfo[cpu]); 336 tcbinfo[cpu].cpu = cpu; 337 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB, 338 &tcbinfo[cpu].hashmask); 339 tcbinfo[cpu].porthashbase = porthashbase; 340 tcbinfo[cpu].porthashmask = porthashmask; 341 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB, 342 &tcbinfo[cpu].wildcardhashmask); 343 tcbinfo[cpu].ipi_zone = ipi_zone; 344 TAILQ_INIT(&tcpcbackq[cpu]); 345 } 346 347 tcp_reass_maxseg = nmbclusters / 16; 348 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg); 349 350 #ifdef INET6 351 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 352 #else 353 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 354 #endif 355 if (max_protohdr < TCP_MINPROTOHDR) 356 max_protohdr = TCP_MINPROTOHDR; 357 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 358 panic("tcp_init"); 359 #undef TCP_MINPROTOHDR 360 361 /* 362 * Initialize TCP statistics counters for each CPU. 363 */ 364 #ifdef SMP 365 for (cpu = 0; cpu < ncpus; ++cpu) { 366 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats)); 367 } 368 #else 369 bzero(&tcpstat, sizeof(struct tcp_stats)); 370 #endif 371 372 syncache_init(); 373 tcp_thread_init(); 374 } 375 376 void 377 tcpmsg_service_loop(void *dummy) 378 { 379 struct netmsg *msg; 380 381 while ((msg = lwkt_waitport(&curthread->td_msgport, 0))) { 382 do { 383 logtcp(rxmsg); 384 msg->nm_dispatch(msg); 385 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL); 386 logtcp(delayed); 387 tcp_willblock(); 388 logtcp(wait); 389 } 390 } 391 392 static void 393 tcp_willblock(void) 394 { 395 struct tcpcb *tp; 396 int cpu = mycpu->gd_cpuid; 397 398 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) { 399 KKASSERT(tp->t_flags & TF_ONOUTPUTQ); 400 tp->t_flags &= ~TF_ONOUTPUTQ; 401 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq); 402 tcp_output(tp); 403 } 404 } 405 406 407 /* 408 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 409 * tcp_template used to store this data in mbufs, but we now recopy it out 410 * of the tcpcb each time to conserve mbufs. 411 */ 412 void 413 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr) 414 { 415 struct inpcb *inp = tp->t_inpcb; 416 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 417 418 #ifdef INET6 419 if (inp->inp_vflag & INP_IPV6) { 420 struct ip6_hdr *ip6; 421 422 ip6 = (struct ip6_hdr *)ip_ptr; 423 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 424 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 425 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 426 (IPV6_VERSION & IPV6_VERSION_MASK); 427 ip6->ip6_nxt = IPPROTO_TCP; 428 ip6->ip6_plen = sizeof(struct tcphdr); 429 ip6->ip6_src = inp->in6p_laddr; 430 ip6->ip6_dst = inp->in6p_faddr; 431 tcp_hdr->th_sum = 0; 432 } else 433 #endif 434 { 435 struct ip *ip = (struct ip *) ip_ptr; 436 437 ip->ip_vhl = IP_VHL_BORING; 438 ip->ip_tos = 0; 439 ip->ip_len = 0; 440 ip->ip_id = 0; 441 ip->ip_off = 0; 442 ip->ip_ttl = 0; 443 ip->ip_sum = 0; 444 ip->ip_p = IPPROTO_TCP; 445 ip->ip_src = inp->inp_laddr; 446 ip->ip_dst = inp->inp_faddr; 447 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, 448 ip->ip_dst.s_addr, 449 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 450 } 451 452 tcp_hdr->th_sport = inp->inp_lport; 453 tcp_hdr->th_dport = inp->inp_fport; 454 tcp_hdr->th_seq = 0; 455 tcp_hdr->th_ack = 0; 456 tcp_hdr->th_x2 = 0; 457 tcp_hdr->th_off = 5; 458 tcp_hdr->th_flags = 0; 459 tcp_hdr->th_win = 0; 460 tcp_hdr->th_urp = 0; 461 } 462 463 /* 464 * Create template to be used to send tcp packets on a connection. 465 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 466 * use for this function is in keepalives, which use tcp_respond. 467 */ 468 struct tcptemp * 469 tcp_maketemplate(struct tcpcb *tp) 470 { 471 struct tcptemp *tmp; 472 473 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL) 474 return (NULL); 475 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t); 476 return (tmp); 477 } 478 479 void 480 tcp_freetemplate(struct tcptemp *tmp) 481 { 482 mpipe_free(&tcptemp_mpipe, tmp); 483 } 484 485 /* 486 * Send a single message to the TCP at address specified by 487 * the given TCP/IP header. If m == NULL, then we make a copy 488 * of the tcpiphdr at ti and send directly to the addressed host. 489 * This is used to force keep alive messages out using the TCP 490 * template for a connection. If flags are given then we send 491 * a message back to the TCP which originated the * segment ti, 492 * and discard the mbuf containing it and any other attached mbufs. 493 * 494 * In any case the ack and sequence number of the transmitted 495 * segment are as specified by the parameters. 496 * 497 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 498 */ 499 void 500 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 501 tcp_seq ack, tcp_seq seq, int flags) 502 { 503 int tlen; 504 int win = 0; 505 struct route *ro = NULL; 506 struct route sro; 507 struct ip *ip = ipgen; 508 struct tcphdr *nth; 509 int ipflags = 0; 510 struct route_in6 *ro6 = NULL; 511 struct route_in6 sro6; 512 struct ip6_hdr *ip6 = ipgen; 513 #ifdef INET6 514 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6); 515 #else 516 const boolean_t isipv6 = FALSE; 517 #endif 518 519 if (tp != NULL) { 520 if (!(flags & TH_RST)) { 521 win = ssb_space(&tp->t_inpcb->inp_socket->so_rcv); 522 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 523 win = (long)TCP_MAXWIN << tp->rcv_scale; 524 } 525 if (isipv6) 526 ro6 = &tp->t_inpcb->in6p_route; 527 else 528 ro = &tp->t_inpcb->inp_route; 529 } else { 530 if (isipv6) { 531 ro6 = &sro6; 532 bzero(ro6, sizeof *ro6); 533 } else { 534 ro = &sro; 535 bzero(ro, sizeof *ro); 536 } 537 } 538 if (m == NULL) { 539 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 540 if (m == NULL) 541 return; 542 tlen = 0; 543 m->m_data += max_linkhdr; 544 if (isipv6) { 545 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr)); 546 ip6 = mtod(m, struct ip6_hdr *); 547 nth = (struct tcphdr *)(ip6 + 1); 548 } else { 549 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); 550 ip = mtod(m, struct ip *); 551 nth = (struct tcphdr *)(ip + 1); 552 } 553 bcopy(th, nth, sizeof(struct tcphdr)); 554 flags = TH_ACK; 555 } else { 556 m_freem(m->m_next); 557 m->m_next = NULL; 558 m->m_data = (caddr_t)ipgen; 559 /* m_len is set later */ 560 tlen = 0; 561 #define xchg(a, b, type) { type t; t = a; a = b; b = t; } 562 if (isipv6) { 563 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 564 nth = (struct tcphdr *)(ip6 + 1); 565 } else { 566 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 567 nth = (struct tcphdr *)(ip + 1); 568 } 569 if (th != nth) { 570 /* 571 * this is usually a case when an extension header 572 * exists between the IPv6 header and the 573 * TCP header. 574 */ 575 nth->th_sport = th->th_sport; 576 nth->th_dport = th->th_dport; 577 } 578 xchg(nth->th_dport, nth->th_sport, n_short); 579 #undef xchg 580 } 581 if (isipv6) { 582 ip6->ip6_flow = 0; 583 ip6->ip6_vfc = IPV6_VERSION; 584 ip6->ip6_nxt = IPPROTO_TCP; 585 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen)); 586 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 587 } else { 588 tlen += sizeof(struct tcpiphdr); 589 ip->ip_len = tlen; 590 ip->ip_ttl = ip_defttl; 591 } 592 m->m_len = tlen; 593 m->m_pkthdr.len = tlen; 594 m->m_pkthdr.rcvif = (struct ifnet *) NULL; 595 nth->th_seq = htonl(seq); 596 nth->th_ack = htonl(ack); 597 nth->th_x2 = 0; 598 nth->th_off = sizeof(struct tcphdr) >> 2; 599 nth->th_flags = flags; 600 if (tp != NULL) 601 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 602 else 603 nth->th_win = htons((u_short)win); 604 nth->th_urp = 0; 605 if (isipv6) { 606 nth->th_sum = 0; 607 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 608 sizeof(struct ip6_hdr), 609 tlen - sizeof(struct ip6_hdr)); 610 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 611 (ro6 && ro6->ro_rt) ? 612 ro6->ro_rt->rt_ifp : NULL); 613 } else { 614 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 615 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 616 m->m_pkthdr.csum_flags = CSUM_TCP; 617 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 618 } 619 #ifdef TCPDEBUG 620 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 621 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 622 #endif 623 if (isipv6) { 624 ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 625 tp ? tp->t_inpcb : NULL); 626 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) { 627 RTFREE(ro6->ro_rt); 628 ro6->ro_rt = NULL; 629 } 630 } else { 631 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 632 if ((ro == &sro) && (ro->ro_rt != NULL)) { 633 RTFREE(ro->ro_rt); 634 ro->ro_rt = NULL; 635 } 636 } 637 } 638 639 /* 640 * Create a new TCP control block, making an 641 * empty reassembly queue and hooking it to the argument 642 * protocol control block. The `inp' parameter must have 643 * come from the zone allocator set up in tcp_init(). 644 */ 645 struct tcpcb * 646 tcp_newtcpcb(struct inpcb *inp) 647 { 648 struct inp_tp *it; 649 struct tcpcb *tp; 650 #ifdef INET6 651 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 652 #else 653 const boolean_t isipv6 = FALSE; 654 #endif 655 656 it = (struct inp_tp *)inp; 657 tp = &it->tcb; 658 bzero(tp, sizeof(struct tcpcb)); 659 LIST_INIT(&tp->t_segq); 660 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt; 661 662 /* Set up our timeouts. */ 663 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt); 664 callout_init(tp->tt_persist = &it->inp_tp_persist); 665 callout_init(tp->tt_keep = &it->inp_tp_keep); 666 callout_init(tp->tt_2msl = &it->inp_tp_2msl); 667 callout_init(tp->tt_delack = &it->inp_tp_delack); 668 669 if (tcp_do_rfc1323) 670 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP); 671 if (tcp_do_rfc1644) 672 tp->t_flags |= TF_REQ_CC; 673 tp->t_inpcb = inp; /* XXX */ 674 tp->t_state = TCPS_CLOSED; 675 /* 676 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 677 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 678 * reasonable initial retransmit time. 679 */ 680 tp->t_srtt = TCPTV_SRTTBASE; 681 tp->t_rttvar = 682 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 683 tp->t_rttmin = tcp_rexmit_min; 684 tp->t_rxtcur = TCPTV_RTOBASE; 685 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 686 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 687 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 688 tp->t_rcvtime = ticks; 689 /* 690 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 691 * because the socket may be bound to an IPv6 wildcard address, 692 * which may match an IPv4-mapped IPv6 address. 693 */ 694 inp->inp_ip_ttl = ip_defttl; 695 inp->inp_ppcb = tp; 696 tcp_sack_tcpcb_init(tp); 697 return (tp); /* XXX */ 698 } 699 700 /* 701 * Drop a TCP connection, reporting the specified error. 702 * If connection is synchronized, then send a RST to peer. 703 */ 704 struct tcpcb * 705 tcp_drop(struct tcpcb *tp, int error) 706 { 707 struct socket *so = tp->t_inpcb->inp_socket; 708 709 if (TCPS_HAVERCVDSYN(tp->t_state)) { 710 tp->t_state = TCPS_CLOSED; 711 tcp_output(tp); 712 tcpstat.tcps_drops++; 713 } else 714 tcpstat.tcps_conndrops++; 715 if (error == ETIMEDOUT && tp->t_softerror) 716 error = tp->t_softerror; 717 so->so_error = error; 718 return (tcp_close(tp)); 719 } 720 721 #ifdef SMP 722 723 struct netmsg_remwildcard { 724 struct netmsg nm_netmsg; 725 struct inpcb *nm_inp; 726 struct inpcbinfo *nm_pcbinfo; 727 #if defined(INET6) 728 int nm_isinet6; 729 #else 730 int nm_unused01; 731 #endif 732 }; 733 734 /* 735 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the 736 * inp can be detached. We do this by cycling through the cpus, ending up 737 * on the cpu controlling the inp last and then doing the disconnect. 738 */ 739 static void 740 in_pcbremwildcardhash_handler(struct netmsg *msg0) 741 { 742 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0; 743 int cpu; 744 745 cpu = msg->nm_pcbinfo->cpu; 746 747 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) { 748 /* note: detach removes any wildcard hash entry */ 749 #ifdef INET6 750 if (msg->nm_isinet6) 751 in6_pcbdetach(msg->nm_inp); 752 else 753 #endif 754 in_pcbdetach(msg->nm_inp); 755 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0); 756 } else { 757 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo); 758 cpu = (cpu + 1) % ncpus2; 759 msg->nm_pcbinfo = &tcbinfo[cpu]; 760 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 761 } 762 } 763 764 #endif 765 766 /* 767 * Close a TCP control block: 768 * discard all space held by the tcp 769 * discard internet protocol block 770 * wake up any sleepers 771 */ 772 struct tcpcb * 773 tcp_close(struct tcpcb *tp) 774 { 775 struct tseg_qent *q; 776 struct inpcb *inp = tp->t_inpcb; 777 struct socket *so = inp->inp_socket; 778 struct rtentry *rt; 779 boolean_t dosavessthresh; 780 #ifdef SMP 781 int cpu; 782 #endif 783 #ifdef INET6 784 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 785 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0); 786 #else 787 const boolean_t isipv6 = FALSE; 788 #endif 789 790 /* 791 * The tp is not instantly destroyed in the wildcard case. Setting 792 * the state to TCPS_TERMINATING will prevent the TCP stack from 793 * messing with it, though it should be noted that this change may 794 * not take effect on other cpus until we have chained the wildcard 795 * hash removal. 796 * 797 * XXX we currently depend on the BGL to synchronize the tp->t_state 798 * update and prevent other tcp protocol threads from accepting new 799 * connections on the listen socket we might be trying to close down. 800 */ 801 KKASSERT(tp->t_state != TCPS_TERMINATING); 802 tp->t_state = TCPS_TERMINATING; 803 804 /* 805 * Make sure that all of our timers are stopped before we 806 * delete the PCB. 807 */ 808 callout_stop(tp->tt_rexmt); 809 callout_stop(tp->tt_persist); 810 callout_stop(tp->tt_keep); 811 callout_stop(tp->tt_2msl); 812 callout_stop(tp->tt_delack); 813 814 if (tp->t_flags & TF_ONOUTPUTQ) { 815 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid); 816 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq); 817 tp->t_flags &= ~TF_ONOUTPUTQ; 818 } 819 820 /* 821 * If we got enough samples through the srtt filter, 822 * save the rtt and rttvar in the routing entry. 823 * 'Enough' is arbitrarily defined as the 16 samples. 824 * 16 samples is enough for the srtt filter to converge 825 * to within 5% of the correct value; fewer samples and 826 * we could save a very bogus rtt. 827 * 828 * Don't update the default route's characteristics and don't 829 * update anything that the user "locked". 830 */ 831 if (tp->t_rttupdated >= 16) { 832 u_long i = 0; 833 834 if (isipv6) { 835 struct sockaddr_in6 *sin6; 836 837 if ((rt = inp->in6p_route.ro_rt) == NULL) 838 goto no_valid_rt; 839 sin6 = (struct sockaddr_in6 *)rt_key(rt); 840 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 841 goto no_valid_rt; 842 } else 843 if ((rt = inp->inp_route.ro_rt) == NULL || 844 ((struct sockaddr_in *)rt_key(rt))-> 845 sin_addr.s_addr == INADDR_ANY) 846 goto no_valid_rt; 847 848 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) { 849 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 850 if (rt->rt_rmx.rmx_rtt && i) 851 /* 852 * filter this update to half the old & half 853 * the new values, converting scale. 854 * See route.h and tcp_var.h for a 855 * description of the scaling constants. 856 */ 857 rt->rt_rmx.rmx_rtt = 858 (rt->rt_rmx.rmx_rtt + i) / 2; 859 else 860 rt->rt_rmx.rmx_rtt = i; 861 tcpstat.tcps_cachedrtt++; 862 } 863 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) { 864 i = tp->t_rttvar * 865 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 866 if (rt->rt_rmx.rmx_rttvar && i) 867 rt->rt_rmx.rmx_rttvar = 868 (rt->rt_rmx.rmx_rttvar + i) / 2; 869 else 870 rt->rt_rmx.rmx_rttvar = i; 871 tcpstat.tcps_cachedrttvar++; 872 } 873 /* 874 * The old comment here said: 875 * update the pipelimit (ssthresh) if it has been updated 876 * already or if a pipesize was specified & the threshhold 877 * got below half the pipesize. I.e., wait for bad news 878 * before we start updating, then update on both good 879 * and bad news. 880 * 881 * But we want to save the ssthresh even if no pipesize is 882 * specified explicitly in the route, because such 883 * connections still have an implicit pipesize specified 884 * by the global tcp_sendspace. In the absence of a reliable 885 * way to calculate the pipesize, it will have to do. 886 */ 887 i = tp->snd_ssthresh; 888 if (rt->rt_rmx.rmx_sendpipe != 0) 889 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2); 890 else 891 dosavessthresh = (i < so->so_snd.ssb_hiwat/2); 892 if (dosavessthresh || 893 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) && 894 (rt->rt_rmx.rmx_ssthresh != 0))) { 895 /* 896 * convert the limit from user data bytes to 897 * packets then to packet data bytes. 898 */ 899 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 900 if (i < 2) 901 i = 2; 902 i *= tp->t_maxseg + 903 (isipv6 ? 904 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 905 sizeof(struct tcpiphdr)); 906 if (rt->rt_rmx.rmx_ssthresh) 907 rt->rt_rmx.rmx_ssthresh = 908 (rt->rt_rmx.rmx_ssthresh + i) / 2; 909 else 910 rt->rt_rmx.rmx_ssthresh = i; 911 tcpstat.tcps_cachedssthresh++; 912 } 913 } 914 915 no_valid_rt: 916 /* free the reassembly queue, if any */ 917 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 918 LIST_REMOVE(q, tqe_q); 919 m_freem(q->tqe_m); 920 FREE(q, M_TSEGQ); 921 tcp_reass_qsize--; 922 } 923 /* throw away SACK blocks in scoreboard*/ 924 if (TCP_DO_SACK(tp)) 925 tcp_sack_cleanup(&tp->scb); 926 927 inp->inp_ppcb = NULL; 928 soisdisconnected(so); 929 /* 930 * Discard the inp. In the SMP case a wildcard inp's hash (created 931 * by a listen socket or an INADDR_ANY udp socket) is replicated 932 * for each protocol thread and must be removed in the context of 933 * that thread. This is accomplished by chaining the message 934 * through the cpus. 935 * 936 * If the inp is not wildcarded we simply detach, which will remove 937 * the any hashes still present for this inp. 938 */ 939 #ifdef SMP 940 if (inp->inp_flags & INP_WILDCARD_MP) { 941 struct netmsg_remwildcard *msg; 942 943 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2; 944 msg = kmalloc(sizeof(struct netmsg_remwildcard), 945 M_LWKTMSG, M_INTWAIT); 946 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0, 947 in_pcbremwildcardhash_handler); 948 #ifdef INET6 949 msg->nm_isinet6 = isafinet6; 950 #endif 951 msg->nm_inp = inp; 952 msg->nm_pcbinfo = &tcbinfo[cpu]; 953 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 954 } else 955 #endif 956 { 957 /* note: detach removes any wildcard hash entry */ 958 #ifdef INET6 959 if (isafinet6) 960 in6_pcbdetach(inp); 961 else 962 #endif 963 in_pcbdetach(inp); 964 } 965 tcpstat.tcps_closed++; 966 return (NULL); 967 } 968 969 static __inline void 970 tcp_drain_oncpu(struct inpcbhead *head) 971 { 972 struct inpcb *inpb; 973 struct tcpcb *tcpb; 974 struct tseg_qent *te; 975 976 LIST_FOREACH(inpb, head, inp_list) { 977 if (inpb->inp_flags & INP_PLACEMARKER) 978 continue; 979 if ((tcpb = intotcpcb(inpb))) { 980 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) { 981 LIST_REMOVE(te, tqe_q); 982 m_freem(te->tqe_m); 983 FREE(te, M_TSEGQ); 984 tcp_reass_qsize--; 985 } 986 } 987 } 988 } 989 990 #ifdef SMP 991 struct netmsg_tcp_drain { 992 struct netmsg nm_netmsg; 993 struct inpcbhead *nm_head; 994 }; 995 996 static void 997 tcp_drain_handler(netmsg_t netmsg) 998 { 999 struct netmsg_tcp_drain *nm = (void *)netmsg; 1000 1001 tcp_drain_oncpu(nm->nm_head); 1002 lwkt_replymsg(&nm->nm_netmsg.nm_lmsg, 0); 1003 } 1004 #endif 1005 1006 void 1007 tcp_drain(void) 1008 { 1009 #ifdef SMP 1010 int cpu; 1011 #endif 1012 1013 if (!do_tcpdrain) 1014 return; 1015 1016 /* 1017 * Walk the tcpbs, if existing, and flush the reassembly queue, 1018 * if there is one... 1019 * XXX: The "Net/3" implementation doesn't imply that the TCP 1020 * reassembly queue should be flushed, but in a situation 1021 * where we're really low on mbufs, this is potentially 1022 * useful. 1023 */ 1024 #ifdef SMP 1025 for (cpu = 0; cpu < ncpus2; cpu++) { 1026 struct netmsg_tcp_drain *msg; 1027 1028 if (cpu == mycpu->gd_cpuid) { 1029 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead); 1030 } else { 1031 msg = kmalloc(sizeof(struct netmsg_tcp_drain), 1032 M_LWKTMSG, M_NOWAIT); 1033 if (msg == NULL) 1034 continue; 1035 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0, 1036 tcp_drain_handler); 1037 msg->nm_head = &tcbinfo[cpu].pcblisthead; 1038 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1039 } 1040 } 1041 #else 1042 tcp_drain_oncpu(&tcbinfo[0].pcblisthead); 1043 #endif 1044 } 1045 1046 /* 1047 * Notify a tcp user of an asynchronous error; 1048 * store error as soft error, but wake up user 1049 * (for now, won't do anything until can select for soft error). 1050 * 1051 * Do not wake up user since there currently is no mechanism for 1052 * reporting soft errors (yet - a kqueue filter may be added). 1053 */ 1054 static void 1055 tcp_notify(struct inpcb *inp, int error) 1056 { 1057 struct tcpcb *tp = intotcpcb(inp); 1058 1059 /* 1060 * Ignore some errors if we are hooked up. 1061 * If connection hasn't completed, has retransmitted several times, 1062 * and receives a second error, give up now. This is better 1063 * than waiting a long time to establish a connection that 1064 * can never complete. 1065 */ 1066 if (tp->t_state == TCPS_ESTABLISHED && 1067 (error == EHOSTUNREACH || error == ENETUNREACH || 1068 error == EHOSTDOWN)) { 1069 return; 1070 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1071 tp->t_softerror) 1072 tcp_drop(tp, error); 1073 else 1074 tp->t_softerror = error; 1075 #if 0 1076 wakeup(&so->so_timeo); 1077 sorwakeup(so); 1078 sowwakeup(so); 1079 #endif 1080 } 1081 1082 static int 1083 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1084 { 1085 int error, i, n; 1086 struct inpcb *marker; 1087 struct inpcb *inp; 1088 inp_gen_t gencnt; 1089 globaldata_t gd; 1090 int origcpu, ccpu; 1091 1092 error = 0; 1093 n = 0; 1094 1095 /* 1096 * The process of preparing the TCB list is too time-consuming and 1097 * resource-intensive to repeat twice on every request. 1098 */ 1099 if (req->oldptr == NULL) { 1100 for (ccpu = 0; ccpu < ncpus; ++ccpu) { 1101 gd = globaldata_find(ccpu); 1102 n += tcbinfo[gd->gd_cpuid].ipi_count; 1103 } 1104 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb); 1105 return (0); 1106 } 1107 1108 if (req->newptr != NULL) 1109 return (EPERM); 1110 1111 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1112 marker->inp_flags |= INP_PLACEMARKER; 1113 1114 /* 1115 * OK, now we're committed to doing something. Run the inpcb list 1116 * for each cpu in the system and construct the output. Use a 1117 * list placemarker to deal with list changes occuring during 1118 * copyout blockages (but otherwise depend on being on the correct 1119 * cpu to avoid races). 1120 */ 1121 origcpu = mycpu->gd_cpuid; 1122 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) { 1123 globaldata_t rgd; 1124 caddr_t inp_ppcb; 1125 struct xtcpcb xt; 1126 int cpu_id; 1127 1128 cpu_id = (origcpu + ccpu) % ncpus; 1129 if ((smp_active_mask & (1 << cpu_id)) == 0) 1130 continue; 1131 rgd = globaldata_find(cpu_id); 1132 lwkt_setcpu_self(rgd); 1133 1134 gencnt = tcbinfo[cpu_id].ipi_gencnt; 1135 n = tcbinfo[cpu_id].ipi_count; 1136 1137 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list); 1138 i = 0; 1139 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) { 1140 /* 1141 * process a snapshot of pcbs, ignoring placemarkers 1142 * and using our own to allow SYSCTL_OUT to block. 1143 */ 1144 LIST_REMOVE(marker, inp_list); 1145 LIST_INSERT_AFTER(inp, marker, inp_list); 1146 1147 if (inp->inp_flags & INP_PLACEMARKER) 1148 continue; 1149 if (inp->inp_gencnt > gencnt) 1150 continue; 1151 if (prison_xinpcb(req->td, inp)) 1152 continue; 1153 1154 xt.xt_len = sizeof xt; 1155 bcopy(inp, &xt.xt_inp, sizeof *inp); 1156 inp_ppcb = inp->inp_ppcb; 1157 if (inp_ppcb != NULL) 1158 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1159 else 1160 bzero(&xt.xt_tp, sizeof xt.xt_tp); 1161 if (inp->inp_socket) 1162 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1163 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0) 1164 break; 1165 ++i; 1166 } 1167 LIST_REMOVE(marker, inp_list); 1168 if (error == 0 && i < n) { 1169 bzero(&xt, sizeof xt); 1170 xt.xt_len = sizeof xt; 1171 while (i < n) { 1172 error = SYSCTL_OUT(req, &xt, sizeof xt); 1173 if (error) 1174 break; 1175 ++i; 1176 } 1177 } 1178 } 1179 1180 /* 1181 * Make sure we are on the same cpu we were on originally, since 1182 * higher level callers expect this. Also don't pollute caches with 1183 * migrated userland data by (eventually) returning to userland 1184 * on a different cpu. 1185 */ 1186 lwkt_setcpu_self(globaldata_find(origcpu)); 1187 kfree(marker, M_TEMP); 1188 return (error); 1189 } 1190 1191 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1192 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1193 1194 static int 1195 tcp_getcred(SYSCTL_HANDLER_ARGS) 1196 { 1197 struct sockaddr_in addrs[2]; 1198 struct inpcb *inp; 1199 int cpu; 1200 int error; 1201 1202 error = suser(req->td); 1203 if (error != 0) 1204 return (error); 1205 error = SYSCTL_IN(req, addrs, sizeof addrs); 1206 if (error != 0) 1207 return (error); 1208 crit_enter(); 1209 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1210 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1211 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1212 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1213 if (inp == NULL || inp->inp_socket == NULL) { 1214 error = ENOENT; 1215 goto out; 1216 } 1217 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1218 out: 1219 crit_exit(); 1220 return (error); 1221 } 1222 1223 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1224 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1225 1226 #ifdef INET6 1227 static int 1228 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1229 { 1230 struct sockaddr_in6 addrs[2]; 1231 struct inpcb *inp; 1232 int error; 1233 boolean_t mapped = FALSE; 1234 1235 error = suser(req->td); 1236 if (error != 0) 1237 return (error); 1238 error = SYSCTL_IN(req, addrs, sizeof addrs); 1239 if (error != 0) 1240 return (error); 1241 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1242 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1243 mapped = TRUE; 1244 else 1245 return (EINVAL); 1246 } 1247 crit_enter(); 1248 if (mapped) { 1249 inp = in_pcblookup_hash(&tcbinfo[0], 1250 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1251 addrs[1].sin6_port, 1252 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1253 addrs[0].sin6_port, 1254 0, NULL); 1255 } else { 1256 inp = in6_pcblookup_hash(&tcbinfo[0], 1257 &addrs[1].sin6_addr, addrs[1].sin6_port, 1258 &addrs[0].sin6_addr, addrs[0].sin6_port, 1259 0, NULL); 1260 } 1261 if (inp == NULL || inp->inp_socket == NULL) { 1262 error = ENOENT; 1263 goto out; 1264 } 1265 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1266 out: 1267 crit_exit(); 1268 return (error); 1269 } 1270 1271 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1272 0, 0, 1273 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1274 #endif 1275 1276 void 1277 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1278 { 1279 struct ip *ip = vip; 1280 struct tcphdr *th; 1281 struct in_addr faddr; 1282 struct inpcb *inp; 1283 struct tcpcb *tp; 1284 void (*notify)(struct inpcb *, int) = tcp_notify; 1285 tcp_seq icmpseq; 1286 int arg, cpu; 1287 1288 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) { 1289 return; 1290 } 1291 1292 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1293 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1294 return; 1295 1296 arg = inetctlerrmap[cmd]; 1297 if (cmd == PRC_QUENCH) { 1298 notify = tcp_quench; 1299 } else if (icmp_may_rst && 1300 (cmd == PRC_UNREACH_ADMIN_PROHIB || 1301 cmd == PRC_UNREACH_PORT || 1302 cmd == PRC_TIMXCEED_INTRANS) && 1303 ip != NULL) { 1304 notify = tcp_drop_syn_sent; 1305 } else if (cmd == PRC_MSGSIZE) { 1306 struct icmp *icmp = (struct icmp *) 1307 ((caddr_t)ip - offsetof(struct icmp, icmp_ip)); 1308 1309 arg = ntohs(icmp->icmp_nextmtu); 1310 notify = tcp_mtudisc; 1311 } else if (PRC_IS_REDIRECT(cmd)) { 1312 ip = NULL; 1313 notify = in_rtchange; 1314 } else if (cmd == PRC_HOSTDEAD) { 1315 ip = NULL; 1316 } 1317 1318 if (ip != NULL) { 1319 crit_enter(); 1320 th = (struct tcphdr *)((caddr_t)ip + 1321 (IP_VHL_HL(ip->ip_vhl) << 2)); 1322 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1323 ip->ip_src.s_addr, th->th_sport); 1324 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1325 ip->ip_src, th->th_sport, 0, NULL); 1326 if ((inp != NULL) && (inp->inp_socket != NULL)) { 1327 icmpseq = htonl(th->th_seq); 1328 tp = intotcpcb(inp); 1329 if (SEQ_GEQ(icmpseq, tp->snd_una) && 1330 SEQ_LT(icmpseq, tp->snd_max)) 1331 (*notify)(inp, arg); 1332 } else { 1333 struct in_conninfo inc; 1334 1335 inc.inc_fport = th->th_dport; 1336 inc.inc_lport = th->th_sport; 1337 inc.inc_faddr = faddr; 1338 inc.inc_laddr = ip->ip_src; 1339 #ifdef INET6 1340 inc.inc_isipv6 = 0; 1341 #endif 1342 syncache_unreach(&inc, th); 1343 } 1344 crit_exit(); 1345 } else { 1346 for (cpu = 0; cpu < ncpus2; cpu++) { 1347 in_pcbnotifyall(&tcbinfo[cpu].pcblisthead, faddr, arg, 1348 notify); 1349 } 1350 } 1351 } 1352 1353 #ifdef INET6 1354 void 1355 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1356 { 1357 struct tcphdr th; 1358 void (*notify) (struct inpcb *, int) = tcp_notify; 1359 struct ip6_hdr *ip6; 1360 struct mbuf *m; 1361 struct ip6ctlparam *ip6cp = NULL; 1362 const struct sockaddr_in6 *sa6_src = NULL; 1363 int off; 1364 struct tcp_portonly { 1365 u_int16_t th_sport; 1366 u_int16_t th_dport; 1367 } *thp; 1368 int arg; 1369 1370 if (sa->sa_family != AF_INET6 || 1371 sa->sa_len != sizeof(struct sockaddr_in6)) 1372 return; 1373 1374 arg = 0; 1375 if (cmd == PRC_QUENCH) 1376 notify = tcp_quench; 1377 else if (cmd == PRC_MSGSIZE) { 1378 struct ip6ctlparam *ip6cp = d; 1379 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6; 1380 1381 arg = ntohl(icmp6->icmp6_mtu); 1382 notify = tcp_mtudisc; 1383 } else if (!PRC_IS_REDIRECT(cmd) && 1384 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) { 1385 return; 1386 } 1387 1388 /* if the parameter is from icmp6, decode it. */ 1389 if (d != NULL) { 1390 ip6cp = (struct ip6ctlparam *)d; 1391 m = ip6cp->ip6c_m; 1392 ip6 = ip6cp->ip6c_ip6; 1393 off = ip6cp->ip6c_off; 1394 sa6_src = ip6cp->ip6c_src; 1395 } else { 1396 m = NULL; 1397 ip6 = NULL; 1398 off = 0; /* fool gcc */ 1399 sa6_src = &sa6_any; 1400 } 1401 1402 if (ip6 != NULL) { 1403 struct in_conninfo inc; 1404 /* 1405 * XXX: We assume that when IPV6 is non NULL, 1406 * M and OFF are valid. 1407 */ 1408 1409 /* check if we can safely examine src and dst ports */ 1410 if (m->m_pkthdr.len < off + sizeof *thp) 1411 return; 1412 1413 bzero(&th, sizeof th); 1414 m_copydata(m, off, sizeof *thp, (caddr_t)&th); 1415 1416 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport, 1417 (struct sockaddr *)ip6cp->ip6c_src, 1418 th.th_sport, cmd, arg, notify); 1419 1420 inc.inc_fport = th.th_dport; 1421 inc.inc_lport = th.th_sport; 1422 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1423 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1424 inc.inc_isipv6 = 1; 1425 syncache_unreach(&inc, &th); 1426 } else 1427 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0, 1428 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify); 1429 } 1430 #endif 1431 1432 /* 1433 * Following is where TCP initial sequence number generation occurs. 1434 * 1435 * There are two places where we must use initial sequence numbers: 1436 * 1. In SYN-ACK packets. 1437 * 2. In SYN packets. 1438 * 1439 * All ISNs for SYN-ACK packets are generated by the syncache. See 1440 * tcp_syncache.c for details. 1441 * 1442 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1443 * depends on this property. In addition, these ISNs should be 1444 * unguessable so as to prevent connection hijacking. To satisfy 1445 * the requirements of this situation, the algorithm outlined in 1446 * RFC 1948 is used to generate sequence numbers. 1447 * 1448 * Implementation details: 1449 * 1450 * Time is based off the system timer, and is corrected so that it 1451 * increases by one megabyte per second. This allows for proper 1452 * recycling on high speed LANs while still leaving over an hour 1453 * before rollover. 1454 * 1455 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1456 * between seeding of isn_secret. This is normally set to zero, 1457 * as reseeding should not be necessary. 1458 * 1459 */ 1460 1461 #define ISN_BYTES_PER_SECOND 1048576 1462 1463 u_char isn_secret[32]; 1464 int isn_last_reseed; 1465 MD5_CTX isn_ctx; 1466 1467 tcp_seq 1468 tcp_new_isn(struct tcpcb *tp) 1469 { 1470 u_int32_t md5_buffer[4]; 1471 tcp_seq new_isn; 1472 1473 /* Seed if this is the first use, reseed if requested. */ 1474 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1475 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1476 < (u_int)ticks))) { 1477 read_random_unlimited(&isn_secret, sizeof isn_secret); 1478 isn_last_reseed = ticks; 1479 } 1480 1481 /* Compute the md5 hash and return the ISN. */ 1482 MD5Init(&isn_ctx); 1483 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 1484 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 1485 #ifdef INET6 1486 if (tp->t_inpcb->inp_vflag & INP_IPV6) { 1487 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1488 sizeof(struct in6_addr)); 1489 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1490 sizeof(struct in6_addr)); 1491 } else 1492 #endif 1493 { 1494 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1495 sizeof(struct in_addr)); 1496 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1497 sizeof(struct in_addr)); 1498 } 1499 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1500 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1501 new_isn = (tcp_seq) md5_buffer[0]; 1502 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1503 return (new_isn); 1504 } 1505 1506 /* 1507 * When a source quench is received, close congestion window 1508 * to one segment. We will gradually open it again as we proceed. 1509 */ 1510 void 1511 tcp_quench(struct inpcb *inp, int error) 1512 { 1513 struct tcpcb *tp = intotcpcb(inp); 1514 1515 if (tp != NULL) { 1516 tp->snd_cwnd = tp->t_maxseg; 1517 tp->snd_wacked = 0; 1518 } 1519 } 1520 1521 /* 1522 * When a specific ICMP unreachable message is received and the 1523 * connection state is SYN-SENT, drop the connection. This behavior 1524 * is controlled by the icmp_may_rst sysctl. 1525 */ 1526 void 1527 tcp_drop_syn_sent(struct inpcb *inp, int error) 1528 { 1529 struct tcpcb *tp = intotcpcb(inp); 1530 1531 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT)) 1532 tcp_drop(tp, error); 1533 } 1534 1535 /* 1536 * When a `need fragmentation' ICMP is received, update our idea of the MSS 1537 * based on the new value in the route. Also nudge TCP to send something, 1538 * since we know the packet we just sent was dropped. 1539 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1540 */ 1541 void 1542 tcp_mtudisc(struct inpcb *inp, int mtu) 1543 { 1544 struct tcpcb *tp = intotcpcb(inp); 1545 struct rtentry *rt; 1546 struct socket *so = inp->inp_socket; 1547 int maxopd, mss; 1548 #ifdef INET6 1549 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0); 1550 #else 1551 const boolean_t isipv6 = FALSE; 1552 #endif 1553 1554 if (tp == NULL) 1555 return; 1556 1557 /* 1558 * If no MTU is provided in the ICMP message, use the 1559 * next lower likely value, as specified in RFC 1191. 1560 */ 1561 if (mtu == 0) { 1562 int oldmtu; 1563 1564 oldmtu = tp->t_maxopd + 1565 (isipv6 ? 1566 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1567 sizeof(struct tcpiphdr)); 1568 mtu = ip_next_mtu(oldmtu, 0); 1569 } 1570 1571 if (isipv6) 1572 rt = tcp_rtlookup6(&inp->inp_inc); 1573 else 1574 rt = tcp_rtlookup(&inp->inp_inc); 1575 if (rt != NULL) { 1576 struct rmxp_tao *taop = rmx_taop(rt->rt_rmx); 1577 1578 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu) 1579 mtu = rt->rt_rmx.rmx_mtu; 1580 1581 maxopd = mtu - 1582 (isipv6 ? 1583 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1584 sizeof(struct tcpiphdr)); 1585 1586 /* 1587 * XXX - The following conditional probably violates the TCP 1588 * spec. The problem is that, since we don't know the 1589 * other end's MSS, we are supposed to use a conservative 1590 * default. But, if we do that, then MTU discovery will 1591 * never actually take place, because the conservative 1592 * default is much less than the MTUs typically seen 1593 * on the Internet today. For the moment, we'll sweep 1594 * this under the carpet. 1595 * 1596 * The conservative default might not actually be a problem 1597 * if the only case this occurs is when sending an initial 1598 * SYN with options and data to a host we've never talked 1599 * to before. Then, they will reply with an MSS value which 1600 * will get recorded and the new parameters should get 1601 * recomputed. For Further Study. 1602 */ 1603 if (taop->tao_mssopt != 0 && taop->tao_mssopt < maxopd) 1604 maxopd = taop->tao_mssopt; 1605 } else 1606 maxopd = mtu - 1607 (isipv6 ? 1608 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1609 sizeof(struct tcpiphdr)); 1610 1611 if (tp->t_maxopd <= maxopd) 1612 return; 1613 tp->t_maxopd = maxopd; 1614 1615 mss = maxopd; 1616 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) == 1617 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1618 mss -= TCPOLEN_TSTAMP_APPA; 1619 1620 if ((tp->t_flags & (TF_REQ_CC | TF_RCVD_CC | TF_NOOPT)) == 1621 (TF_REQ_CC | TF_RCVD_CC)) 1622 mss -= TCPOLEN_CC_APPA; 1623 1624 /* round down to multiple of MCLBYTES */ 1625 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */ 1626 if (mss > MCLBYTES) 1627 mss &= ~(MCLBYTES - 1); 1628 #else 1629 if (mss > MCLBYTES) 1630 mss = (mss / MCLBYTES) * MCLBYTES; 1631 #endif 1632 1633 if (so->so_snd.ssb_hiwat < mss) 1634 mss = so->so_snd.ssb_hiwat; 1635 1636 tp->t_maxseg = mss; 1637 tp->t_rtttime = 0; 1638 tp->snd_nxt = tp->snd_una; 1639 tcp_output(tp); 1640 tcpstat.tcps_mturesent++; 1641 } 1642 1643 /* 1644 * Look-up the routing entry to the peer of this inpcb. If no route 1645 * is found and it cannot be allocated the return NULL. This routine 1646 * is called by TCP routines that access the rmx structure and by tcp_mss 1647 * to get the interface MTU. 1648 */ 1649 struct rtentry * 1650 tcp_rtlookup(struct in_conninfo *inc) 1651 { 1652 struct route *ro = &inc->inc_route; 1653 1654 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) { 1655 /* No route yet, so try to acquire one */ 1656 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1657 /* 1658 * unused portions of the structure MUST be zero'd 1659 * out because rtalloc() treats it as opaque data 1660 */ 1661 bzero(&ro->ro_dst, sizeof(struct sockaddr_in)); 1662 ro->ro_dst.sa_family = AF_INET; 1663 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1664 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1665 inc->inc_faddr; 1666 rtalloc(ro); 1667 } 1668 } 1669 return (ro->ro_rt); 1670 } 1671 1672 #ifdef INET6 1673 struct rtentry * 1674 tcp_rtlookup6(struct in_conninfo *inc) 1675 { 1676 struct route_in6 *ro6 = &inc->inc6_route; 1677 1678 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) { 1679 /* No route yet, so try to acquire one */ 1680 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1681 /* 1682 * unused portions of the structure MUST be zero'd 1683 * out because rtalloc() treats it as opaque data 1684 */ 1685 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6)); 1686 ro6->ro_dst.sin6_family = AF_INET6; 1687 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1688 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1689 rtalloc((struct route *)ro6); 1690 } 1691 } 1692 return (ro6->ro_rt); 1693 } 1694 #endif 1695 1696 #ifdef IPSEC 1697 /* compute ESP/AH header size for TCP, including outer IP header. */ 1698 size_t 1699 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1700 { 1701 struct inpcb *inp; 1702 struct mbuf *m; 1703 size_t hdrsiz; 1704 struct ip *ip; 1705 struct tcphdr *th; 1706 1707 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1708 return (0); 1709 MGETHDR(m, MB_DONTWAIT, MT_DATA); 1710 if (!m) 1711 return (0); 1712 1713 #ifdef INET6 1714 if (inp->inp_vflag & INP_IPV6) { 1715 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 1716 1717 th = (struct tcphdr *)(ip6 + 1); 1718 m->m_pkthdr.len = m->m_len = 1719 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1720 tcp_fillheaders(tp, ip6, th); 1721 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1722 } else 1723 #endif 1724 { 1725 ip = mtod(m, struct ip *); 1726 th = (struct tcphdr *)(ip + 1); 1727 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1728 tcp_fillheaders(tp, ip, th); 1729 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1730 } 1731 1732 m_free(m); 1733 return (hdrsiz); 1734 } 1735 #endif 1736 1737 /* 1738 * Return a pointer to the cached information about the remote host. 1739 * The cached information is stored in the protocol specific part of 1740 * the route metrics. 1741 */ 1742 struct rmxp_tao * 1743 tcp_gettaocache(struct in_conninfo *inc) 1744 { 1745 struct rtentry *rt; 1746 1747 #ifdef INET6 1748 if (inc->inc_isipv6) 1749 rt = tcp_rtlookup6(inc); 1750 else 1751 #endif 1752 rt = tcp_rtlookup(inc); 1753 1754 /* Make sure this is a host route and is up. */ 1755 if (rt == NULL || 1756 (rt->rt_flags & (RTF_UP | RTF_HOST)) != (RTF_UP | RTF_HOST)) 1757 return (NULL); 1758 1759 return (rmx_taop(rt->rt_rmx)); 1760 } 1761 1762 /* 1763 * Clear all the TAO cache entries, called from tcp_init. 1764 * 1765 * XXX 1766 * This routine is just an empty one, because we assume that the routing 1767 * routing tables are initialized at the same time when TCP, so there is 1768 * nothing in the cache left over. 1769 */ 1770 static void 1771 tcp_cleartaocache(void) 1772 { 1773 } 1774 1775 /* 1776 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1777 * 1778 * This code attempts to calculate the bandwidth-delay product as a 1779 * means of determining the optimal window size to maximize bandwidth, 1780 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1781 * routers. This code also does a fairly good job keeping RTTs in check 1782 * across slow links like modems. We implement an algorithm which is very 1783 * similar (but not meant to be) TCP/Vegas. The code operates on the 1784 * transmitter side of a TCP connection and so only effects the transmit 1785 * side of the connection. 1786 * 1787 * BACKGROUND: TCP makes no provision for the management of buffer space 1788 * at the end points or at the intermediate routers and switches. A TCP 1789 * stream, whether using NewReno or not, will eventually buffer as 1790 * many packets as it is able and the only reason this typically works is 1791 * due to the fairly small default buffers made available for a connection 1792 * (typicaly 16K or 32K). As machines use larger windows and/or window 1793 * scaling it is now fairly easy for even a single TCP connection to blow-out 1794 * all available buffer space not only on the local interface, but on 1795 * intermediate routers and switches as well. NewReno makes a misguided 1796 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1797 * then backing off, then steadily increasing the window again until another 1798 * failure occurs, ad-infinitum. This results in terrible oscillation that 1799 * is only made worse as network loads increase and the idea of intentionally 1800 * blowing out network buffers is, frankly, a terrible way to manage network 1801 * resources. 1802 * 1803 * It is far better to limit the transmit window prior to the failure 1804 * condition being achieved. There are two general ways to do this: First 1805 * you can 'scan' through different transmit window sizes and locate the 1806 * point where the RTT stops increasing, indicating that you have filled the 1807 * pipe, then scan backwards until you note that RTT stops decreasing, then 1808 * repeat ad-infinitum. This method works in principle but has severe 1809 * implementation issues due to RTT variances, timer granularity, and 1810 * instability in the algorithm which can lead to many false positives and 1811 * create oscillations as well as interact badly with other TCP streams 1812 * implementing the same algorithm. 1813 * 1814 * The second method is to limit the window to the bandwidth delay product 1815 * of the link. This is the method we implement. RTT variances and our 1816 * own manipulation of the congestion window, bwnd, can potentially 1817 * destabilize the algorithm. For this reason we have to stabilize the 1818 * elements used to calculate the window. We do this by using the minimum 1819 * observed RTT, the long term average of the observed bandwidth, and 1820 * by adding two segments worth of slop. It isn't perfect but it is able 1821 * to react to changing conditions and gives us a very stable basis on 1822 * which to extend the algorithm. 1823 */ 1824 void 1825 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1826 { 1827 u_long bw; 1828 u_long bwnd; 1829 int save_ticks; 1830 int delta_ticks; 1831 1832 /* 1833 * If inflight_enable is disabled in the middle of a tcp connection, 1834 * make sure snd_bwnd is effectively disabled. 1835 */ 1836 if (!tcp_inflight_enable) { 1837 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1838 tp->snd_bandwidth = 0; 1839 return; 1840 } 1841 1842 /* 1843 * Validate the delta time. If a connection is new or has been idle 1844 * a long time we have to reset the bandwidth calculator. 1845 */ 1846 save_ticks = ticks; 1847 delta_ticks = save_ticks - tp->t_bw_rtttime; 1848 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) { 1849 tp->t_bw_rtttime = ticks; 1850 tp->t_bw_rtseq = ack_seq; 1851 if (tp->snd_bandwidth == 0) 1852 tp->snd_bandwidth = tcp_inflight_min; 1853 return; 1854 } 1855 if (delta_ticks == 0) 1856 return; 1857 1858 /* 1859 * Sanity check, plus ignore pure window update acks. 1860 */ 1861 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0) 1862 return; 1863 1864 /* 1865 * Figure out the bandwidth. Due to the tick granularity this 1866 * is a very rough number and it MUST be averaged over a fairly 1867 * long period of time. XXX we need to take into account a link 1868 * that is not using all available bandwidth, but for now our 1869 * slop will ramp us up if this case occurs and the bandwidth later 1870 * increases. 1871 */ 1872 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks; 1873 tp->t_bw_rtttime = save_ticks; 1874 tp->t_bw_rtseq = ack_seq; 1875 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1876 1877 tp->snd_bandwidth = bw; 1878 1879 /* 1880 * Calculate the semi-static bandwidth delay product, plus two maximal 1881 * segments. The additional slop puts us squarely in the sweet 1882 * spot and also handles the bandwidth run-up case. Without the 1883 * slop we could be locking ourselves into a lower bandwidth. 1884 * 1885 * Situations Handled: 1886 * (1) Prevents over-queueing of packets on LANs, especially on 1887 * high speed LANs, allowing larger TCP buffers to be 1888 * specified, and also does a good job preventing 1889 * over-queueing of packets over choke points like modems 1890 * (at least for the transmit side). 1891 * 1892 * (2) Is able to handle changing network loads (bandwidth 1893 * drops so bwnd drops, bandwidth increases so bwnd 1894 * increases). 1895 * 1896 * (3) Theoretically should stabilize in the face of multiple 1897 * connections implementing the same algorithm (this may need 1898 * a little work). 1899 * 1900 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1901 * be adjusted with a sysctl but typically only needs to be on 1902 * very slow connections. A value no smaller then 5 should 1903 * be used, but only reduce this default if you have no other 1904 * choice. 1905 */ 1906 1907 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1908 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + 1909 tcp_inflight_stab * (int)tp->t_maxseg / 10; 1910 #undef USERTT 1911 1912 if (tcp_inflight_debug > 0) { 1913 static int ltime; 1914 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1915 ltime = ticks; 1916 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1917 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd); 1918 } 1919 } 1920 if ((long)bwnd < tcp_inflight_min) 1921 bwnd = tcp_inflight_min; 1922 if (bwnd > tcp_inflight_max) 1923 bwnd = tcp_inflight_max; 1924 if ((long)bwnd < tp->t_maxseg * 2) 1925 bwnd = tp->t_maxseg * 2; 1926 tp->snd_bwnd = bwnd; 1927 } 1928