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 1.63 2008/11/11 10:46:58 sephe 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/priv.h> 89 #include <sys/socket.h> 90 #include <sys/socketvar.h> 91 #include <sys/protosw.h> 92 #include <sys/random.h> 93 #include <sys/in_cksum.h> 94 #include <sys/ktr.h> 95 96 #include <vm/vm_zone.h> 97 98 #include <net/route.h> 99 #include <net/if.h> 100 #include <net/netisr.h> 101 102 #define _IP_VHL 103 #include <netinet/in.h> 104 #include <netinet/in_systm.h> 105 #include <netinet/ip.h> 106 #include <netinet/ip6.h> 107 #include <netinet/in_pcb.h> 108 #include <netinet6/in6_pcb.h> 109 #include <netinet/in_var.h> 110 #include <netinet/ip_var.h> 111 #include <netinet6/ip6_var.h> 112 #include <netinet/ip_icmp.h> 113 #ifdef INET6 114 #include <netinet/icmp6.h> 115 #endif 116 #include <netinet/tcp.h> 117 #include <netinet/tcp_fsm.h> 118 #include <netinet/tcp_seq.h> 119 #include <netinet/tcp_timer.h> 120 #include <netinet/tcp_timer2.h> 121 #include <netinet/tcp_var.h> 122 #include <netinet6/tcp6_var.h> 123 #include <netinet/tcpip.h> 124 #ifdef TCPDEBUG 125 #include <netinet/tcp_debug.h> 126 #endif 127 #include <netinet6/ip6protosw.h> 128 129 #ifdef IPSEC 130 #include <netinet6/ipsec.h> 131 #ifdef INET6 132 #include <netinet6/ipsec6.h> 133 #endif 134 #endif 135 136 #ifdef FAST_IPSEC 137 #include <netproto/ipsec/ipsec.h> 138 #ifdef INET6 139 #include <netproto/ipsec/ipsec6.h> 140 #endif 141 #define IPSEC 142 #endif 143 144 #include <sys/md5.h> 145 #include <sys/msgport2.h> 146 #include <machine/smp.h> 147 148 #include <net/netmsg2.h> 149 150 #if !defined(KTR_TCP) 151 #define KTR_TCP KTR_ALL 152 #endif 153 KTR_INFO_MASTER(tcp); 154 KTR_INFO(KTR_TCP, tcp, rxmsg, 0, "tcp getmsg", 0); 155 KTR_INFO(KTR_TCP, tcp, wait, 1, "tcp waitmsg", 0); 156 KTR_INFO(KTR_TCP, tcp, delayed, 2, "tcp execute delayed ops", 0); 157 #define logtcp(name) KTR_LOG(tcp_ ## name) 158 159 struct inpcbinfo tcbinfo[MAXCPU]; 160 struct tcpcbackqhead tcpcbackq[MAXCPU]; 161 162 int tcp_mpsafe_proto = 0; 163 TUNABLE_INT("net.inet.tcp.mpsafe_proto", &tcp_mpsafe_proto); 164 165 static int tcp_mpsafe_thread = NETMSG_SERVICE_ADAPTIVE; 166 TUNABLE_INT("net.inet.tcp.mpsafe_thread", &tcp_mpsafe_thread); 167 SYSCTL_INT(_net_inet_tcp, OID_AUTO, mpsafe_thread, CTLFLAG_RW, 168 &tcp_mpsafe_thread, 0, 169 "0:BGL, 1:Adaptive BGL, 2:No BGL(experimental)"); 170 171 int tcp_mssdflt = TCP_MSS; 172 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 173 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size"); 174 175 #ifdef INET6 176 int tcp_v6mssdflt = TCP6_MSS; 177 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW, 178 &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6"); 179 #endif 180 181 /* 182 * Minimum MSS we accept and use. This prevents DoS attacks where 183 * we are forced to a ridiculous low MSS like 20 and send hundreds 184 * of packets instead of one. The effect scales with the available 185 * bandwidth and quickly saturates the CPU and network interface 186 * with packet generation and sending. Set to zero to disable MINMSS 187 * checking. This setting prevents us from sending too small packets. 188 */ 189 int tcp_minmss = TCP_MINMSS; 190 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 191 &tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 192 193 #if 0 194 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 195 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 196 &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time"); 197 #endif 198 199 int tcp_do_rfc1323 = 1; 200 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 201 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions"); 202 203 static int tcp_tcbhashsize = 0; 204 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 205 &tcp_tcbhashsize, 0, "Size of TCP control block hashtable"); 206 207 static int do_tcpdrain = 1; 208 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 209 "Enable tcp_drain routine for extra help when low on mbufs"); 210 211 /* XXX JH */ 212 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 213 &tcbinfo[0].ipi_count, 0, "Number of active PCBs"); 214 215 static int icmp_may_rst = 1; 216 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 217 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 218 219 static int tcp_isn_reseed_interval = 0; 220 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 221 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 222 223 /* 224 * TCP bandwidth limiting sysctls. The inflight limiter is now turned on 225 * by default, but with generous values which should allow maximal 226 * bandwidth. In particular, the slop defaults to 50 (5 packets). 227 * 228 * The reason for doing this is that the limiter is the only mechanism we 229 * have which seems to do a really good job preventing receiver RX rings 230 * on network interfaces from getting blown out. Even though GigE/10GigE 231 * is supposed to flow control it looks like either it doesn't actually 232 * do it or Open Source drivers do not properly enable it. 233 * 234 * People using the limiter to reduce bottlenecks on slower WAN connections 235 * should set the slop to 20 (2 packets). 236 */ 237 static int tcp_inflight_enable = 1; 238 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW, 239 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 240 241 static int tcp_inflight_debug = 0; 242 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW, 243 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 244 245 static int tcp_inflight_min = 6144; 246 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW, 247 &tcp_inflight_min, 0, "Lower bound for TCP inflight window"); 248 249 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 250 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW, 251 &tcp_inflight_max, 0, "Upper bound for TCP inflight window"); 252 253 static int tcp_inflight_stab = 50; 254 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW, 255 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 3 packets)"); 256 257 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives"); 258 static struct malloc_pipe tcptemp_mpipe; 259 260 static void tcp_willblock(int); 261 static void tcp_notify (struct inpcb *, int); 262 263 struct tcp_stats tcpstats_percpu[MAXCPU]; 264 #ifdef SMP 265 static int 266 sysctl_tcpstats(SYSCTL_HANDLER_ARGS) 267 { 268 int cpu, error = 0; 269 270 for (cpu = 0; cpu < ncpus; ++cpu) { 271 if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu], 272 sizeof(struct tcp_stats)))) 273 break; 274 if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu], 275 sizeof(struct tcp_stats)))) 276 break; 277 } 278 279 return (error); 280 } 281 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 282 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics"); 283 #else 284 SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW, 285 &tcpstat, tcp_stats, "TCP statistics"); 286 #endif 287 288 /* 289 * Target size of TCP PCB hash tables. Must be a power of two. 290 * 291 * Note that this can be overridden by the kernel environment 292 * variable net.inet.tcp.tcbhashsize 293 */ 294 #ifndef TCBHASHSIZE 295 #define TCBHASHSIZE 512 296 #endif 297 298 /* 299 * This is the actual shape of what we allocate using the zone 300 * allocator. Doing it this way allows us to protect both structures 301 * using the same generation count, and also eliminates the overhead 302 * of allocating tcpcbs separately. By hiding the structure here, 303 * we avoid changing most of the rest of the code (although it needs 304 * to be changed, eventually, for greater efficiency). 305 */ 306 #define ALIGNMENT 32 307 #define ALIGNM1 (ALIGNMENT - 1) 308 struct inp_tp { 309 union { 310 struct inpcb inp; 311 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 312 } inp_tp_u; 313 struct tcpcb tcb; 314 struct tcp_callout inp_tp_rexmt; 315 struct tcp_callout inp_tp_persist; 316 struct tcp_callout inp_tp_keep; 317 struct tcp_callout inp_tp_2msl; 318 struct tcp_callout inp_tp_delack; 319 struct netmsg_tcp_timer inp_tp_timermsg; 320 }; 321 #undef ALIGNMENT 322 #undef ALIGNM1 323 324 /* 325 * Tcp initialization 326 */ 327 void 328 tcp_init(void) 329 { 330 struct inpcbporthead *porthashbase; 331 u_long porthashmask; 332 struct vm_zone *ipi_zone; 333 int hashsize = TCBHASHSIZE; 334 int cpu; 335 336 /* 337 * note: tcptemp is used for keepalives, and it is ok for an 338 * allocation to fail so do not specify MPF_INT. 339 */ 340 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp), 341 25, -1, 0, NULL); 342 343 tcp_delacktime = TCPTV_DELACK; 344 tcp_keepinit = TCPTV_KEEP_INIT; 345 tcp_keepidle = TCPTV_KEEP_IDLE; 346 tcp_keepintvl = TCPTV_KEEPINTVL; 347 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 348 tcp_msl = TCPTV_MSL; 349 tcp_rexmit_min = TCPTV_MIN; 350 tcp_rexmit_slop = TCPTV_CPU_VAR; 351 352 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 353 if (!powerof2(hashsize)) { 354 kprintf("WARNING: TCB hash size not a power of 2\n"); 355 hashsize = 512; /* safe default */ 356 } 357 tcp_tcbhashsize = hashsize; 358 porthashbase = hashinit(hashsize, M_PCB, &porthashmask); 359 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 360 ZONE_INTERRUPT, 0); 361 362 for (cpu = 0; cpu < ncpus2; cpu++) { 363 in_pcbinfo_init(&tcbinfo[cpu]); 364 tcbinfo[cpu].cpu = cpu; 365 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB, 366 &tcbinfo[cpu].hashmask); 367 tcbinfo[cpu].porthashbase = porthashbase; 368 tcbinfo[cpu].porthashmask = porthashmask; 369 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB, 370 &tcbinfo[cpu].wildcardhashmask); 371 tcbinfo[cpu].ipi_zone = ipi_zone; 372 TAILQ_INIT(&tcpcbackq[cpu]); 373 } 374 375 tcp_reass_maxseg = nmbclusters / 16; 376 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg); 377 378 #ifdef INET6 379 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 380 #else 381 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 382 #endif 383 if (max_protohdr < TCP_MINPROTOHDR) 384 max_protohdr = TCP_MINPROTOHDR; 385 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 386 panic("tcp_init"); 387 #undef TCP_MINPROTOHDR 388 389 /* 390 * Initialize TCP statistics counters for each CPU. 391 */ 392 #ifdef SMP 393 for (cpu = 0; cpu < ncpus; ++cpu) { 394 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats)); 395 } 396 #else 397 bzero(&tcpstat, sizeof(struct tcp_stats)); 398 #endif 399 400 syncache_init(); 401 tcp_thread_init(); 402 } 403 404 void 405 tcpmsg_service_loop(void *dummy) 406 { 407 struct netmsg *msg; 408 int mplocked; 409 410 /* 411 * Thread was started with TDF_MPSAFE 412 */ 413 mplocked = 0; 414 415 while ((msg = lwkt_waitport(&curthread->td_msgport, 0))) { 416 do { 417 logtcp(rxmsg); 418 mplocked = netmsg_service(msg, tcp_mpsafe_thread, 419 mplocked); 420 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL); 421 422 logtcp(delayed); 423 tcp_willblock(mplocked); 424 logtcp(wait); 425 } 426 } 427 428 static void 429 tcp_willblock(int mplocked) 430 { 431 struct tcpcb *tp; 432 int cpu = mycpu->gd_cpuid; 433 int unlock = 0; 434 435 if (!mplocked && !tcp_mpsafe_proto) { 436 if (TAILQ_EMPTY(&tcpcbackq[cpu])) 437 return; 438 439 get_mplock(); 440 mplocked = 1; 441 unlock = 1; 442 } 443 444 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) { 445 KKASSERT(tp->t_flags & TF_ONOUTPUTQ); 446 tp->t_flags &= ~TF_ONOUTPUTQ; 447 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq); 448 tcp_output(tp); 449 } 450 451 if (unlock) 452 rel_mplock(); 453 } 454 455 456 /* 457 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 458 * tcp_template used to store this data in mbufs, but we now recopy it out 459 * of the tcpcb each time to conserve mbufs. 460 */ 461 void 462 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr) 463 { 464 struct inpcb *inp = tp->t_inpcb; 465 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 466 467 #ifdef INET6 468 if (inp->inp_vflag & INP_IPV6) { 469 struct ip6_hdr *ip6; 470 471 ip6 = (struct ip6_hdr *)ip_ptr; 472 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 473 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 474 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 475 (IPV6_VERSION & IPV6_VERSION_MASK); 476 ip6->ip6_nxt = IPPROTO_TCP; 477 ip6->ip6_plen = sizeof(struct tcphdr); 478 ip6->ip6_src = inp->in6p_laddr; 479 ip6->ip6_dst = inp->in6p_faddr; 480 tcp_hdr->th_sum = 0; 481 } else 482 #endif 483 { 484 struct ip *ip = (struct ip *) ip_ptr; 485 486 ip->ip_vhl = IP_VHL_BORING; 487 ip->ip_tos = 0; 488 ip->ip_len = 0; 489 ip->ip_id = 0; 490 ip->ip_off = 0; 491 ip->ip_ttl = 0; 492 ip->ip_sum = 0; 493 ip->ip_p = IPPROTO_TCP; 494 ip->ip_src = inp->inp_laddr; 495 ip->ip_dst = inp->inp_faddr; 496 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, 497 ip->ip_dst.s_addr, 498 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 499 } 500 501 tcp_hdr->th_sport = inp->inp_lport; 502 tcp_hdr->th_dport = inp->inp_fport; 503 tcp_hdr->th_seq = 0; 504 tcp_hdr->th_ack = 0; 505 tcp_hdr->th_x2 = 0; 506 tcp_hdr->th_off = 5; 507 tcp_hdr->th_flags = 0; 508 tcp_hdr->th_win = 0; 509 tcp_hdr->th_urp = 0; 510 } 511 512 /* 513 * Create template to be used to send tcp packets on a connection. 514 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 515 * use for this function is in keepalives, which use tcp_respond. 516 */ 517 struct tcptemp * 518 tcp_maketemplate(struct tcpcb *tp) 519 { 520 struct tcptemp *tmp; 521 522 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL) 523 return (NULL); 524 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t); 525 return (tmp); 526 } 527 528 void 529 tcp_freetemplate(struct tcptemp *tmp) 530 { 531 mpipe_free(&tcptemp_mpipe, tmp); 532 } 533 534 /* 535 * Send a single message to the TCP at address specified by 536 * the given TCP/IP header. If m == NULL, then we make a copy 537 * of the tcpiphdr at ti and send directly to the addressed host. 538 * This is used to force keep alive messages out using the TCP 539 * template for a connection. If flags are given then we send 540 * a message back to the TCP which originated the * segment ti, 541 * and discard the mbuf containing it and any other attached mbufs. 542 * 543 * In any case the ack and sequence number of the transmitted 544 * segment are as specified by the parameters. 545 * 546 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 547 */ 548 void 549 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 550 tcp_seq ack, tcp_seq seq, int flags) 551 { 552 int tlen; 553 int win = 0; 554 struct route *ro = NULL; 555 struct route sro; 556 struct ip *ip = ipgen; 557 struct tcphdr *nth; 558 int ipflags = 0; 559 struct route_in6 *ro6 = NULL; 560 struct route_in6 sro6; 561 struct ip6_hdr *ip6 = ipgen; 562 boolean_t use_tmpro = TRUE; 563 #ifdef INET6 564 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6); 565 #else 566 const boolean_t isipv6 = FALSE; 567 #endif 568 569 if (tp != NULL) { 570 if (!(flags & TH_RST)) { 571 win = ssb_space(&tp->t_inpcb->inp_socket->so_rcv); 572 if (win < 0) 573 win = 0; 574 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 575 win = (long)TCP_MAXWIN << tp->rcv_scale; 576 } 577 /* 578 * Don't use the route cache of a listen socket, 579 * it is not MPSAFE; use temporary route cache. 580 */ 581 if (tp->t_state != TCPS_LISTEN) { 582 if (isipv6) 583 ro6 = &tp->t_inpcb->in6p_route; 584 else 585 ro = &tp->t_inpcb->inp_route; 586 use_tmpro = FALSE; 587 } 588 } 589 if (use_tmpro) { 590 if (isipv6) { 591 ro6 = &sro6; 592 bzero(ro6, sizeof *ro6); 593 } else { 594 ro = &sro; 595 bzero(ro, sizeof *ro); 596 } 597 } 598 if (m == NULL) { 599 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 600 if (m == NULL) 601 return; 602 tlen = 0; 603 m->m_data += max_linkhdr; 604 if (isipv6) { 605 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr)); 606 ip6 = mtod(m, struct ip6_hdr *); 607 nth = (struct tcphdr *)(ip6 + 1); 608 } else { 609 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); 610 ip = mtod(m, struct ip *); 611 nth = (struct tcphdr *)(ip + 1); 612 } 613 bcopy(th, nth, sizeof(struct tcphdr)); 614 flags = TH_ACK; 615 } else { 616 m_freem(m->m_next); 617 m->m_next = NULL; 618 m->m_data = (caddr_t)ipgen; 619 /* m_len is set later */ 620 tlen = 0; 621 #define xchg(a, b, type) { type t; t = a; a = b; b = t; } 622 if (isipv6) { 623 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 624 nth = (struct tcphdr *)(ip6 + 1); 625 } else { 626 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 627 nth = (struct tcphdr *)(ip + 1); 628 } 629 if (th != nth) { 630 /* 631 * this is usually a case when an extension header 632 * exists between the IPv6 header and the 633 * TCP header. 634 */ 635 nth->th_sport = th->th_sport; 636 nth->th_dport = th->th_dport; 637 } 638 xchg(nth->th_dport, nth->th_sport, n_short); 639 #undef xchg 640 } 641 if (isipv6) { 642 ip6->ip6_flow = 0; 643 ip6->ip6_vfc = IPV6_VERSION; 644 ip6->ip6_nxt = IPPROTO_TCP; 645 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen)); 646 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 647 } else { 648 tlen += sizeof(struct tcpiphdr); 649 ip->ip_len = tlen; 650 ip->ip_ttl = ip_defttl; 651 } 652 m->m_len = tlen; 653 m->m_pkthdr.len = tlen; 654 m->m_pkthdr.rcvif = NULL; 655 nth->th_seq = htonl(seq); 656 nth->th_ack = htonl(ack); 657 nth->th_x2 = 0; 658 nth->th_off = sizeof(struct tcphdr) >> 2; 659 nth->th_flags = flags; 660 if (tp != NULL) 661 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 662 else 663 nth->th_win = htons((u_short)win); 664 nth->th_urp = 0; 665 if (isipv6) { 666 nth->th_sum = 0; 667 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 668 sizeof(struct ip6_hdr), 669 tlen - sizeof(struct ip6_hdr)); 670 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 671 (ro6 && ro6->ro_rt) ? 672 ro6->ro_rt->rt_ifp : NULL); 673 } else { 674 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 675 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 676 m->m_pkthdr.csum_flags = CSUM_TCP; 677 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 678 } 679 #ifdef TCPDEBUG 680 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 681 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 682 #endif 683 if (isipv6) { 684 ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 685 tp ? tp->t_inpcb : NULL); 686 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) { 687 RTFREE(ro6->ro_rt); 688 ro6->ro_rt = NULL; 689 } 690 } else { 691 ipflags |= IP_DEBUGROUTE; 692 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 693 if ((ro == &sro) && (ro->ro_rt != NULL)) { 694 RTFREE(ro->ro_rt); 695 ro->ro_rt = NULL; 696 } 697 } 698 } 699 700 /* 701 * Create a new TCP control block, making an 702 * empty reassembly queue and hooking it to the argument 703 * protocol control block. The `inp' parameter must have 704 * come from the zone allocator set up in tcp_init(). 705 */ 706 struct tcpcb * 707 tcp_newtcpcb(struct inpcb *inp) 708 { 709 struct inp_tp *it; 710 struct tcpcb *tp; 711 #ifdef INET6 712 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 713 #else 714 const boolean_t isipv6 = FALSE; 715 #endif 716 717 it = (struct inp_tp *)inp; 718 tp = &it->tcb; 719 bzero(tp, sizeof(struct tcpcb)); 720 LIST_INIT(&tp->t_segq); 721 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt; 722 723 /* Set up our timeouts. */ 724 tp->tt_rexmt = &it->inp_tp_rexmt; 725 tp->tt_persist = &it->inp_tp_persist; 726 tp->tt_keep = &it->inp_tp_keep; 727 tp->tt_2msl = &it->inp_tp_2msl; 728 tp->tt_delack = &it->inp_tp_delack; 729 tcp_inittimers(tp); 730 731 /* 732 * Zero out timer message. We don't create it here, 733 * since the current CPU may not be the owner of this 734 * inpcb. 735 */ 736 tp->tt_msg = &it->inp_tp_timermsg; 737 bzero(tp->tt_msg, sizeof(*tp->tt_msg)); 738 739 if (tcp_do_rfc1323) 740 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP); 741 tp->t_inpcb = inp; /* XXX */ 742 tp->t_state = TCPS_CLOSED; 743 /* 744 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 745 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 746 * reasonable initial retransmit time. 747 */ 748 tp->t_srtt = TCPTV_SRTTBASE; 749 tp->t_rttvar = 750 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 751 tp->t_rttmin = tcp_rexmit_min; 752 tp->t_rxtcur = TCPTV_RTOBASE; 753 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 754 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 755 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 756 tp->t_rcvtime = ticks; 757 /* 758 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 759 * because the socket may be bound to an IPv6 wildcard address, 760 * which may match an IPv4-mapped IPv6 address. 761 */ 762 inp->inp_ip_ttl = ip_defttl; 763 inp->inp_ppcb = tp; 764 tcp_sack_tcpcb_init(tp); 765 return (tp); /* XXX */ 766 } 767 768 /* 769 * Drop a TCP connection, reporting the specified error. 770 * If connection is synchronized, then send a RST to peer. 771 */ 772 struct tcpcb * 773 tcp_drop(struct tcpcb *tp, int error) 774 { 775 struct socket *so = tp->t_inpcb->inp_socket; 776 777 if (TCPS_HAVERCVDSYN(tp->t_state)) { 778 tp->t_state = TCPS_CLOSED; 779 tcp_output(tp); 780 tcpstat.tcps_drops++; 781 } else 782 tcpstat.tcps_conndrops++; 783 if (error == ETIMEDOUT && tp->t_softerror) 784 error = tp->t_softerror; 785 so->so_error = error; 786 return (tcp_close(tp)); 787 } 788 789 #ifdef SMP 790 791 struct netmsg_remwildcard { 792 struct netmsg nm_netmsg; 793 struct inpcb *nm_inp; 794 struct inpcbinfo *nm_pcbinfo; 795 #if defined(INET6) 796 int nm_isinet6; 797 #else 798 int nm_unused01; 799 #endif 800 }; 801 802 /* 803 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the 804 * inp can be detached. We do this by cycling through the cpus, ending up 805 * on the cpu controlling the inp last and then doing the disconnect. 806 */ 807 static void 808 in_pcbremwildcardhash_handler(struct netmsg *msg0) 809 { 810 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0; 811 int cpu; 812 813 cpu = msg->nm_pcbinfo->cpu; 814 815 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) { 816 /* note: detach removes any wildcard hash entry */ 817 #ifdef INET6 818 if (msg->nm_isinet6) 819 in6_pcbdetach(msg->nm_inp); 820 else 821 #endif 822 in_pcbdetach(msg->nm_inp); 823 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0); 824 } else { 825 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo); 826 cpu = (cpu + 1) % ncpus2; 827 msg->nm_pcbinfo = &tcbinfo[cpu]; 828 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 829 } 830 } 831 832 #endif 833 834 /* 835 * Close a TCP control block: 836 * discard all space held by the tcp 837 * discard internet protocol block 838 * wake up any sleepers 839 */ 840 struct tcpcb * 841 tcp_close(struct tcpcb *tp) 842 { 843 struct tseg_qent *q; 844 struct inpcb *inp = tp->t_inpcb; 845 struct socket *so = inp->inp_socket; 846 struct rtentry *rt; 847 boolean_t dosavessthresh; 848 #ifdef SMP 849 int cpu; 850 #endif 851 #ifdef INET6 852 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 853 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0); 854 #else 855 const boolean_t isipv6 = FALSE; 856 #endif 857 858 /* 859 * The tp is not instantly destroyed in the wildcard case. Setting 860 * the state to TCPS_TERMINATING will prevent the TCP stack from 861 * messing with it, though it should be noted that this change may 862 * not take effect on other cpus until we have chained the wildcard 863 * hash removal. 864 * 865 * XXX we currently depend on the BGL to synchronize the tp->t_state 866 * update and prevent other tcp protocol threads from accepting new 867 * connections on the listen socket we might be trying to close down. 868 */ 869 KKASSERT(tp->t_state != TCPS_TERMINATING); 870 tp->t_state = TCPS_TERMINATING; 871 872 /* 873 * Make sure that all of our timers are stopped before we 874 * delete the PCB. For listen TCP socket (tp->tt_msg == NULL), 875 * timers are never used. If timer message is never created 876 * (tp->tt_msg->tt_tcb == NULL), timers are never used too. 877 */ 878 if (tp->tt_msg != NULL && tp->tt_msg->tt_tcb != NULL) { 879 tcp_callout_stop(tp, tp->tt_rexmt); 880 tcp_callout_stop(tp, tp->tt_persist); 881 tcp_callout_stop(tp, tp->tt_keep); 882 tcp_callout_stop(tp, tp->tt_2msl); 883 tcp_callout_stop(tp, tp->tt_delack); 884 } 885 886 if (tp->t_flags & TF_ONOUTPUTQ) { 887 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid); 888 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq); 889 tp->t_flags &= ~TF_ONOUTPUTQ; 890 } 891 892 /* 893 * If we got enough samples through the srtt filter, 894 * save the rtt and rttvar in the routing entry. 895 * 'Enough' is arbitrarily defined as the 16 samples. 896 * 16 samples is enough for the srtt filter to converge 897 * to within 5% of the correct value; fewer samples and 898 * we could save a very bogus rtt. 899 * 900 * Don't update the default route's characteristics and don't 901 * update anything that the user "locked". 902 */ 903 if (tp->t_rttupdated >= 16) { 904 u_long i = 0; 905 906 if (isipv6) { 907 struct sockaddr_in6 *sin6; 908 909 if ((rt = inp->in6p_route.ro_rt) == NULL) 910 goto no_valid_rt; 911 sin6 = (struct sockaddr_in6 *)rt_key(rt); 912 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 913 goto no_valid_rt; 914 } else 915 if ((rt = inp->inp_route.ro_rt) == NULL || 916 ((struct sockaddr_in *)rt_key(rt))-> 917 sin_addr.s_addr == INADDR_ANY) 918 goto no_valid_rt; 919 920 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) { 921 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 922 if (rt->rt_rmx.rmx_rtt && i) 923 /* 924 * filter this update to half the old & half 925 * the new values, converting scale. 926 * See route.h and tcp_var.h for a 927 * description of the scaling constants. 928 */ 929 rt->rt_rmx.rmx_rtt = 930 (rt->rt_rmx.rmx_rtt + i) / 2; 931 else 932 rt->rt_rmx.rmx_rtt = i; 933 tcpstat.tcps_cachedrtt++; 934 } 935 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) { 936 i = tp->t_rttvar * 937 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 938 if (rt->rt_rmx.rmx_rttvar && i) 939 rt->rt_rmx.rmx_rttvar = 940 (rt->rt_rmx.rmx_rttvar + i) / 2; 941 else 942 rt->rt_rmx.rmx_rttvar = i; 943 tcpstat.tcps_cachedrttvar++; 944 } 945 /* 946 * The old comment here said: 947 * update the pipelimit (ssthresh) if it has been updated 948 * already or if a pipesize was specified & the threshhold 949 * got below half the pipesize. I.e., wait for bad news 950 * before we start updating, then update on both good 951 * and bad news. 952 * 953 * But we want to save the ssthresh even if no pipesize is 954 * specified explicitly in the route, because such 955 * connections still have an implicit pipesize specified 956 * by the global tcp_sendspace. In the absence of a reliable 957 * way to calculate the pipesize, it will have to do. 958 */ 959 i = tp->snd_ssthresh; 960 if (rt->rt_rmx.rmx_sendpipe != 0) 961 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2); 962 else 963 dosavessthresh = (i < so->so_snd.ssb_hiwat/2); 964 if (dosavessthresh || 965 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) && 966 (rt->rt_rmx.rmx_ssthresh != 0))) { 967 /* 968 * convert the limit from user data bytes to 969 * packets then to packet data bytes. 970 */ 971 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 972 if (i < 2) 973 i = 2; 974 i *= tp->t_maxseg + 975 (isipv6 ? 976 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 977 sizeof(struct tcpiphdr)); 978 if (rt->rt_rmx.rmx_ssthresh) 979 rt->rt_rmx.rmx_ssthresh = 980 (rt->rt_rmx.rmx_ssthresh + i) / 2; 981 else 982 rt->rt_rmx.rmx_ssthresh = i; 983 tcpstat.tcps_cachedssthresh++; 984 } 985 } 986 987 no_valid_rt: 988 /* free the reassembly queue, if any */ 989 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 990 LIST_REMOVE(q, tqe_q); 991 m_freem(q->tqe_m); 992 FREE(q, M_TSEGQ); 993 tcp_reass_qsize--; 994 } 995 /* throw away SACK blocks in scoreboard*/ 996 if (TCP_DO_SACK(tp)) 997 tcp_sack_cleanup(&tp->scb); 998 999 inp->inp_ppcb = NULL; 1000 soisdisconnected(so); 1001 1002 tcp_destroy_timermsg(tp); 1003 1004 /* 1005 * Discard the inp. In the SMP case a wildcard inp's hash (created 1006 * by a listen socket or an INADDR_ANY udp socket) is replicated 1007 * for each protocol thread and must be removed in the context of 1008 * that thread. This is accomplished by chaining the message 1009 * through the cpus. 1010 * 1011 * If the inp is not wildcarded we simply detach, which will remove 1012 * the any hashes still present for this inp. 1013 */ 1014 #ifdef SMP 1015 if (inp->inp_flags & INP_WILDCARD_MP) { 1016 struct netmsg_remwildcard *msg; 1017 1018 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2; 1019 msg = kmalloc(sizeof(struct netmsg_remwildcard), 1020 M_LWKTMSG, M_INTWAIT); 1021 netmsg_init(&msg->nm_netmsg, NULL, &netisr_afree_rport, 1022 0, in_pcbremwildcardhash_handler); 1023 #ifdef INET6 1024 msg->nm_isinet6 = isafinet6; 1025 #endif 1026 msg->nm_inp = inp; 1027 msg->nm_pcbinfo = &tcbinfo[cpu]; 1028 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1029 } else 1030 #endif 1031 { 1032 /* note: detach removes any wildcard hash entry */ 1033 #ifdef INET6 1034 if (isafinet6) 1035 in6_pcbdetach(inp); 1036 else 1037 #endif 1038 in_pcbdetach(inp); 1039 } 1040 tcpstat.tcps_closed++; 1041 return (NULL); 1042 } 1043 1044 static __inline void 1045 tcp_drain_oncpu(struct inpcbhead *head) 1046 { 1047 struct inpcb *inpb; 1048 struct tcpcb *tcpb; 1049 struct tseg_qent *te; 1050 1051 LIST_FOREACH(inpb, head, inp_list) { 1052 if (inpb->inp_flags & INP_PLACEMARKER) 1053 continue; 1054 if ((tcpb = intotcpcb(inpb))) { 1055 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) { 1056 LIST_REMOVE(te, tqe_q); 1057 m_freem(te->tqe_m); 1058 FREE(te, M_TSEGQ); 1059 tcp_reass_qsize--; 1060 } 1061 } 1062 } 1063 } 1064 1065 #ifdef SMP 1066 struct netmsg_tcp_drain { 1067 struct netmsg nm_netmsg; 1068 struct inpcbhead *nm_head; 1069 }; 1070 1071 static void 1072 tcp_drain_handler(netmsg_t netmsg) 1073 { 1074 struct netmsg_tcp_drain *nm = (void *)netmsg; 1075 1076 tcp_drain_oncpu(nm->nm_head); 1077 lwkt_replymsg(&nm->nm_netmsg.nm_lmsg, 0); 1078 } 1079 #endif 1080 1081 void 1082 tcp_drain(void) 1083 { 1084 #ifdef SMP 1085 int cpu; 1086 #endif 1087 1088 if (!do_tcpdrain) 1089 return; 1090 1091 /* 1092 * Walk the tcpbs, if existing, and flush the reassembly queue, 1093 * if there is one... 1094 * XXX: The "Net/3" implementation doesn't imply that the TCP 1095 * reassembly queue should be flushed, but in a situation 1096 * where we're really low on mbufs, this is potentially 1097 * useful. 1098 */ 1099 #ifdef SMP 1100 for (cpu = 0; cpu < ncpus2; cpu++) { 1101 struct netmsg_tcp_drain *msg; 1102 1103 if (cpu == mycpu->gd_cpuid) { 1104 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead); 1105 } else { 1106 msg = kmalloc(sizeof(struct netmsg_tcp_drain), 1107 M_LWKTMSG, M_NOWAIT); 1108 if (msg == NULL) 1109 continue; 1110 netmsg_init(&msg->nm_netmsg, NULL, &netisr_afree_rport, 1111 0, tcp_drain_handler); 1112 msg->nm_head = &tcbinfo[cpu].pcblisthead; 1113 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1114 } 1115 } 1116 #else 1117 tcp_drain_oncpu(&tcbinfo[0].pcblisthead); 1118 #endif 1119 } 1120 1121 /* 1122 * Notify a tcp user of an asynchronous error; 1123 * store error as soft error, but wake up user 1124 * (for now, won't do anything until can select for soft error). 1125 * 1126 * Do not wake up user since there currently is no mechanism for 1127 * reporting soft errors (yet - a kqueue filter may be added). 1128 */ 1129 static void 1130 tcp_notify(struct inpcb *inp, int error) 1131 { 1132 struct tcpcb *tp = intotcpcb(inp); 1133 1134 /* 1135 * Ignore some errors if we are hooked up. 1136 * If connection hasn't completed, has retransmitted several times, 1137 * and receives a second error, give up now. This is better 1138 * than waiting a long time to establish a connection that 1139 * can never complete. 1140 */ 1141 if (tp->t_state == TCPS_ESTABLISHED && 1142 (error == EHOSTUNREACH || error == ENETUNREACH || 1143 error == EHOSTDOWN)) { 1144 return; 1145 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1146 tp->t_softerror) 1147 tcp_drop(tp, error); 1148 else 1149 tp->t_softerror = error; 1150 #if 0 1151 wakeup(&so->so_timeo); 1152 sorwakeup(so); 1153 sowwakeup(so); 1154 #endif 1155 } 1156 1157 static int 1158 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1159 { 1160 int error, i, n; 1161 struct inpcb *marker; 1162 struct inpcb *inp; 1163 inp_gen_t gencnt; 1164 globaldata_t gd; 1165 int origcpu, ccpu; 1166 1167 error = 0; 1168 n = 0; 1169 1170 /* 1171 * The process of preparing the TCB list is too time-consuming and 1172 * resource-intensive to repeat twice on every request. 1173 */ 1174 if (req->oldptr == NULL) { 1175 for (ccpu = 0; ccpu < ncpus; ++ccpu) { 1176 gd = globaldata_find(ccpu); 1177 n += tcbinfo[gd->gd_cpuid].ipi_count; 1178 } 1179 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb); 1180 return (0); 1181 } 1182 1183 if (req->newptr != NULL) 1184 return (EPERM); 1185 1186 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1187 marker->inp_flags |= INP_PLACEMARKER; 1188 1189 /* 1190 * OK, now we're committed to doing something. Run the inpcb list 1191 * for each cpu in the system and construct the output. Use a 1192 * list placemarker to deal with list changes occuring during 1193 * copyout blockages (but otherwise depend on being on the correct 1194 * cpu to avoid races). 1195 */ 1196 origcpu = mycpu->gd_cpuid; 1197 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) { 1198 globaldata_t rgd; 1199 caddr_t inp_ppcb; 1200 struct xtcpcb xt; 1201 int cpu_id; 1202 1203 cpu_id = (origcpu + ccpu) % ncpus; 1204 if ((smp_active_mask & (1 << cpu_id)) == 0) 1205 continue; 1206 rgd = globaldata_find(cpu_id); 1207 lwkt_setcpu_self(rgd); 1208 1209 gencnt = tcbinfo[cpu_id].ipi_gencnt; 1210 n = tcbinfo[cpu_id].ipi_count; 1211 1212 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list); 1213 i = 0; 1214 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) { 1215 /* 1216 * process a snapshot of pcbs, ignoring placemarkers 1217 * and using our own to allow SYSCTL_OUT to block. 1218 */ 1219 LIST_REMOVE(marker, inp_list); 1220 LIST_INSERT_AFTER(inp, marker, inp_list); 1221 1222 if (inp->inp_flags & INP_PLACEMARKER) 1223 continue; 1224 if (inp->inp_gencnt > gencnt) 1225 continue; 1226 if (prison_xinpcb(req->td, inp)) 1227 continue; 1228 1229 xt.xt_len = sizeof xt; 1230 bcopy(inp, &xt.xt_inp, sizeof *inp); 1231 inp_ppcb = inp->inp_ppcb; 1232 if (inp_ppcb != NULL) 1233 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1234 else 1235 bzero(&xt.xt_tp, sizeof xt.xt_tp); 1236 if (inp->inp_socket) 1237 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1238 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0) 1239 break; 1240 ++i; 1241 } 1242 LIST_REMOVE(marker, inp_list); 1243 if (error == 0 && i < n) { 1244 bzero(&xt, sizeof xt); 1245 xt.xt_len = sizeof xt; 1246 while (i < n) { 1247 error = SYSCTL_OUT(req, &xt, sizeof xt); 1248 if (error) 1249 break; 1250 ++i; 1251 } 1252 } 1253 } 1254 1255 /* 1256 * Make sure we are on the same cpu we were on originally, since 1257 * higher level callers expect this. Also don't pollute caches with 1258 * migrated userland data by (eventually) returning to userland 1259 * on a different cpu. 1260 */ 1261 lwkt_setcpu_self(globaldata_find(origcpu)); 1262 kfree(marker, M_TEMP); 1263 return (error); 1264 } 1265 1266 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1267 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1268 1269 static int 1270 tcp_getcred(SYSCTL_HANDLER_ARGS) 1271 { 1272 struct sockaddr_in addrs[2]; 1273 struct inpcb *inp; 1274 int cpu; 1275 int error; 1276 1277 error = priv_check(req->td, PRIV_ROOT); 1278 if (error != 0) 1279 return (error); 1280 error = SYSCTL_IN(req, addrs, sizeof addrs); 1281 if (error != 0) 1282 return (error); 1283 crit_enter(); 1284 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1285 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1286 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1287 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1288 if (inp == NULL || inp->inp_socket == NULL) { 1289 error = ENOENT; 1290 goto out; 1291 } 1292 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1293 out: 1294 crit_exit(); 1295 return (error); 1296 } 1297 1298 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1299 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1300 1301 #ifdef INET6 1302 static int 1303 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1304 { 1305 struct sockaddr_in6 addrs[2]; 1306 struct inpcb *inp; 1307 int error; 1308 boolean_t mapped = FALSE; 1309 1310 error = priv_check(req->td, PRIV_ROOT); 1311 if (error != 0) 1312 return (error); 1313 error = SYSCTL_IN(req, addrs, sizeof addrs); 1314 if (error != 0) 1315 return (error); 1316 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1317 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1318 mapped = TRUE; 1319 else 1320 return (EINVAL); 1321 } 1322 crit_enter(); 1323 if (mapped) { 1324 inp = in_pcblookup_hash(&tcbinfo[0], 1325 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1326 addrs[1].sin6_port, 1327 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1328 addrs[0].sin6_port, 1329 0, NULL); 1330 } else { 1331 inp = in6_pcblookup_hash(&tcbinfo[0], 1332 &addrs[1].sin6_addr, addrs[1].sin6_port, 1333 &addrs[0].sin6_addr, addrs[0].sin6_port, 1334 0, NULL); 1335 } 1336 if (inp == NULL || inp->inp_socket == NULL) { 1337 error = ENOENT; 1338 goto out; 1339 } 1340 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1341 out: 1342 crit_exit(); 1343 return (error); 1344 } 1345 1346 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1347 0, 0, 1348 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1349 #endif 1350 1351 struct netmsg_tcp_notify { 1352 struct netmsg nm_nmsg; 1353 void (*nm_notify)(struct inpcb *, int); 1354 struct in_addr nm_faddr; 1355 int nm_arg; 1356 }; 1357 1358 static void 1359 tcp_notifyall_oncpu(struct netmsg *netmsg) 1360 { 1361 struct netmsg_tcp_notify *nmsg = (struct netmsg_tcp_notify *)netmsg; 1362 int nextcpu; 1363 1364 in_pcbnotifyall(&tcbinfo[mycpuid].pcblisthead, nmsg->nm_faddr, 1365 nmsg->nm_arg, nmsg->nm_notify); 1366 1367 nextcpu = mycpuid + 1; 1368 if (nextcpu < ncpus2) 1369 lwkt_forwardmsg(tcp_cport(nextcpu), &netmsg->nm_lmsg); 1370 else 1371 lwkt_replymsg(&netmsg->nm_lmsg, 0); 1372 } 1373 1374 void 1375 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1376 { 1377 struct ip *ip = vip; 1378 struct tcphdr *th; 1379 struct in_addr faddr; 1380 struct inpcb *inp; 1381 struct tcpcb *tp; 1382 void (*notify)(struct inpcb *, int) = tcp_notify; 1383 tcp_seq icmpseq; 1384 int arg, cpu; 1385 1386 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) { 1387 return; 1388 } 1389 1390 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1391 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1392 return; 1393 1394 arg = inetctlerrmap[cmd]; 1395 if (cmd == PRC_QUENCH) { 1396 notify = tcp_quench; 1397 } else if (icmp_may_rst && 1398 (cmd == PRC_UNREACH_ADMIN_PROHIB || 1399 cmd == PRC_UNREACH_PORT || 1400 cmd == PRC_TIMXCEED_INTRANS) && 1401 ip != NULL) { 1402 notify = tcp_drop_syn_sent; 1403 } else if (cmd == PRC_MSGSIZE) { 1404 struct icmp *icmp = (struct icmp *) 1405 ((caddr_t)ip - offsetof(struct icmp, icmp_ip)); 1406 1407 arg = ntohs(icmp->icmp_nextmtu); 1408 notify = tcp_mtudisc; 1409 } else if (PRC_IS_REDIRECT(cmd)) { 1410 ip = NULL; 1411 notify = in_rtchange; 1412 } else if (cmd == PRC_HOSTDEAD) { 1413 ip = NULL; 1414 } 1415 1416 if (ip != NULL) { 1417 crit_enter(); 1418 th = (struct tcphdr *)((caddr_t)ip + 1419 (IP_VHL_HL(ip->ip_vhl) << 2)); 1420 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1421 ip->ip_src.s_addr, th->th_sport); 1422 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1423 ip->ip_src, th->th_sport, 0, NULL); 1424 if ((inp != NULL) && (inp->inp_socket != NULL)) { 1425 icmpseq = htonl(th->th_seq); 1426 tp = intotcpcb(inp); 1427 if (SEQ_GEQ(icmpseq, tp->snd_una) && 1428 SEQ_LT(icmpseq, tp->snd_max)) 1429 (*notify)(inp, arg); 1430 } else { 1431 struct in_conninfo inc; 1432 1433 inc.inc_fport = th->th_dport; 1434 inc.inc_lport = th->th_sport; 1435 inc.inc_faddr = faddr; 1436 inc.inc_laddr = ip->ip_src; 1437 #ifdef INET6 1438 inc.inc_isipv6 = 0; 1439 #endif 1440 syncache_unreach(&inc, th); 1441 } 1442 crit_exit(); 1443 } else { 1444 struct netmsg_tcp_notify nmsg; 1445 1446 KKASSERT(&curthread->td_msgport == cpu_portfn(0)); 1447 netmsg_init(&nmsg.nm_nmsg, NULL, &curthread->td_msgport, 1448 0, tcp_notifyall_oncpu); 1449 nmsg.nm_faddr = faddr; 1450 nmsg.nm_arg = arg; 1451 nmsg.nm_notify = notify; 1452 1453 lwkt_domsg(tcp_cport(0), &nmsg.nm_nmsg.nm_lmsg, 0); 1454 } 1455 } 1456 1457 #ifdef INET6 1458 void 1459 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1460 { 1461 struct tcphdr th; 1462 void (*notify) (struct inpcb *, int) = tcp_notify; 1463 struct ip6_hdr *ip6; 1464 struct mbuf *m; 1465 struct ip6ctlparam *ip6cp = NULL; 1466 const struct sockaddr_in6 *sa6_src = NULL; 1467 int off; 1468 struct tcp_portonly { 1469 u_int16_t th_sport; 1470 u_int16_t th_dport; 1471 } *thp; 1472 int arg; 1473 1474 if (sa->sa_family != AF_INET6 || 1475 sa->sa_len != sizeof(struct sockaddr_in6)) 1476 return; 1477 1478 arg = 0; 1479 if (cmd == PRC_QUENCH) 1480 notify = tcp_quench; 1481 else if (cmd == PRC_MSGSIZE) { 1482 struct ip6ctlparam *ip6cp = d; 1483 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6; 1484 1485 arg = ntohl(icmp6->icmp6_mtu); 1486 notify = tcp_mtudisc; 1487 } else if (!PRC_IS_REDIRECT(cmd) && 1488 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) { 1489 return; 1490 } 1491 1492 /* if the parameter is from icmp6, decode it. */ 1493 if (d != NULL) { 1494 ip6cp = (struct ip6ctlparam *)d; 1495 m = ip6cp->ip6c_m; 1496 ip6 = ip6cp->ip6c_ip6; 1497 off = ip6cp->ip6c_off; 1498 sa6_src = ip6cp->ip6c_src; 1499 } else { 1500 m = NULL; 1501 ip6 = NULL; 1502 off = 0; /* fool gcc */ 1503 sa6_src = &sa6_any; 1504 } 1505 1506 if (ip6 != NULL) { 1507 struct in_conninfo inc; 1508 /* 1509 * XXX: We assume that when IPV6 is non NULL, 1510 * M and OFF are valid. 1511 */ 1512 1513 /* check if we can safely examine src and dst ports */ 1514 if (m->m_pkthdr.len < off + sizeof *thp) 1515 return; 1516 1517 bzero(&th, sizeof th); 1518 m_copydata(m, off, sizeof *thp, (caddr_t)&th); 1519 1520 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport, 1521 (struct sockaddr *)ip6cp->ip6c_src, 1522 th.th_sport, cmd, arg, notify); 1523 1524 inc.inc_fport = th.th_dport; 1525 inc.inc_lport = th.th_sport; 1526 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1527 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1528 inc.inc_isipv6 = 1; 1529 syncache_unreach(&inc, &th); 1530 } else 1531 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0, 1532 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify); 1533 } 1534 #endif 1535 1536 /* 1537 * Following is where TCP initial sequence number generation occurs. 1538 * 1539 * There are two places where we must use initial sequence numbers: 1540 * 1. In SYN-ACK packets. 1541 * 2. In SYN packets. 1542 * 1543 * All ISNs for SYN-ACK packets are generated by the syncache. See 1544 * tcp_syncache.c for details. 1545 * 1546 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1547 * depends on this property. In addition, these ISNs should be 1548 * unguessable so as to prevent connection hijacking. To satisfy 1549 * the requirements of this situation, the algorithm outlined in 1550 * RFC 1948 is used to generate sequence numbers. 1551 * 1552 * Implementation details: 1553 * 1554 * Time is based off the system timer, and is corrected so that it 1555 * increases by one megabyte per second. This allows for proper 1556 * recycling on high speed LANs while still leaving over an hour 1557 * before rollover. 1558 * 1559 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1560 * between seeding of isn_secret. This is normally set to zero, 1561 * as reseeding should not be necessary. 1562 * 1563 */ 1564 1565 #define ISN_BYTES_PER_SECOND 1048576 1566 1567 u_char isn_secret[32]; 1568 int isn_last_reseed; 1569 MD5_CTX isn_ctx; 1570 1571 tcp_seq 1572 tcp_new_isn(struct tcpcb *tp) 1573 { 1574 u_int32_t md5_buffer[4]; 1575 tcp_seq new_isn; 1576 1577 /* Seed if this is the first use, reseed if requested. */ 1578 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1579 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1580 < (u_int)ticks))) { 1581 read_random_unlimited(&isn_secret, sizeof isn_secret); 1582 isn_last_reseed = ticks; 1583 } 1584 1585 /* Compute the md5 hash and return the ISN. */ 1586 MD5Init(&isn_ctx); 1587 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 1588 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 1589 #ifdef INET6 1590 if (tp->t_inpcb->inp_vflag & INP_IPV6) { 1591 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1592 sizeof(struct in6_addr)); 1593 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1594 sizeof(struct in6_addr)); 1595 } else 1596 #endif 1597 { 1598 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1599 sizeof(struct in_addr)); 1600 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1601 sizeof(struct in_addr)); 1602 } 1603 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1604 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1605 new_isn = (tcp_seq) md5_buffer[0]; 1606 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1607 return (new_isn); 1608 } 1609 1610 /* 1611 * When a source quench is received, close congestion window 1612 * to one segment. We will gradually open it again as we proceed. 1613 */ 1614 void 1615 tcp_quench(struct inpcb *inp, int error) 1616 { 1617 struct tcpcb *tp = intotcpcb(inp); 1618 1619 if (tp != NULL) { 1620 tp->snd_cwnd = tp->t_maxseg; 1621 tp->snd_wacked = 0; 1622 } 1623 } 1624 1625 /* 1626 * When a specific ICMP unreachable message is received and the 1627 * connection state is SYN-SENT, drop the connection. This behavior 1628 * is controlled by the icmp_may_rst sysctl. 1629 */ 1630 void 1631 tcp_drop_syn_sent(struct inpcb *inp, int error) 1632 { 1633 struct tcpcb *tp = intotcpcb(inp); 1634 1635 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT)) 1636 tcp_drop(tp, error); 1637 } 1638 1639 /* 1640 * When a `need fragmentation' ICMP is received, update our idea of the MSS 1641 * based on the new value in the route. Also nudge TCP to send something, 1642 * since we know the packet we just sent was dropped. 1643 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1644 */ 1645 void 1646 tcp_mtudisc(struct inpcb *inp, int mtu) 1647 { 1648 struct tcpcb *tp = intotcpcb(inp); 1649 struct rtentry *rt; 1650 struct socket *so = inp->inp_socket; 1651 int maxopd, mss; 1652 #ifdef INET6 1653 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0); 1654 #else 1655 const boolean_t isipv6 = FALSE; 1656 #endif 1657 1658 if (tp == NULL) 1659 return; 1660 1661 /* 1662 * If no MTU is provided in the ICMP message, use the 1663 * next lower likely value, as specified in RFC 1191. 1664 */ 1665 if (mtu == 0) { 1666 int oldmtu; 1667 1668 oldmtu = tp->t_maxopd + 1669 (isipv6 ? 1670 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1671 sizeof(struct tcpiphdr)); 1672 mtu = ip_next_mtu(oldmtu, 0); 1673 } 1674 1675 if (isipv6) 1676 rt = tcp_rtlookup6(&inp->inp_inc); 1677 else 1678 rt = tcp_rtlookup(&inp->inp_inc); 1679 if (rt != NULL) { 1680 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu) 1681 mtu = rt->rt_rmx.rmx_mtu; 1682 1683 maxopd = mtu - 1684 (isipv6 ? 1685 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1686 sizeof(struct tcpiphdr)); 1687 1688 /* 1689 * XXX - The following conditional probably violates the TCP 1690 * spec. The problem is that, since we don't know the 1691 * other end's MSS, we are supposed to use a conservative 1692 * default. But, if we do that, then MTU discovery will 1693 * never actually take place, because the conservative 1694 * default is much less than the MTUs typically seen 1695 * on the Internet today. For the moment, we'll sweep 1696 * this under the carpet. 1697 * 1698 * The conservative default might not actually be a problem 1699 * if the only case this occurs is when sending an initial 1700 * SYN with options and data to a host we've never talked 1701 * to before. Then, they will reply with an MSS value which 1702 * will get recorded and the new parameters should get 1703 * recomputed. For Further Study. 1704 */ 1705 if (rt->rt_rmx.rmx_mssopt && rt->rt_rmx.rmx_mssopt < maxopd) 1706 maxopd = rt->rt_rmx.rmx_mssopt; 1707 } else 1708 maxopd = mtu - 1709 (isipv6 ? 1710 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1711 sizeof(struct tcpiphdr)); 1712 1713 if (tp->t_maxopd <= maxopd) 1714 return; 1715 tp->t_maxopd = maxopd; 1716 1717 mss = maxopd; 1718 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) == 1719 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1720 mss -= TCPOLEN_TSTAMP_APPA; 1721 1722 /* round down to multiple of MCLBYTES */ 1723 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */ 1724 if (mss > MCLBYTES) 1725 mss &= ~(MCLBYTES - 1); 1726 #else 1727 if (mss > MCLBYTES) 1728 mss = (mss / MCLBYTES) * MCLBYTES; 1729 #endif 1730 1731 if (so->so_snd.ssb_hiwat < mss) 1732 mss = so->so_snd.ssb_hiwat; 1733 1734 tp->t_maxseg = mss; 1735 tp->t_rtttime = 0; 1736 tp->snd_nxt = tp->snd_una; 1737 tcp_output(tp); 1738 tcpstat.tcps_mturesent++; 1739 } 1740 1741 /* 1742 * Look-up the routing entry to the peer of this inpcb. If no route 1743 * is found and it cannot be allocated the return NULL. This routine 1744 * is called by TCP routines that access the rmx structure and by tcp_mss 1745 * to get the interface MTU. 1746 */ 1747 struct rtentry * 1748 tcp_rtlookup(struct in_conninfo *inc) 1749 { 1750 struct route *ro = &inc->inc_route; 1751 1752 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) { 1753 /* No route yet, so try to acquire one */ 1754 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1755 /* 1756 * unused portions of the structure MUST be zero'd 1757 * out because rtalloc() treats it as opaque data 1758 */ 1759 bzero(&ro->ro_dst, sizeof(struct sockaddr_in)); 1760 ro->ro_dst.sa_family = AF_INET; 1761 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1762 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1763 inc->inc_faddr; 1764 rtalloc(ro); 1765 } 1766 } 1767 return (ro->ro_rt); 1768 } 1769 1770 #ifdef INET6 1771 struct rtentry * 1772 tcp_rtlookup6(struct in_conninfo *inc) 1773 { 1774 struct route_in6 *ro6 = &inc->inc6_route; 1775 1776 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) { 1777 /* No route yet, so try to acquire one */ 1778 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1779 /* 1780 * unused portions of the structure MUST be zero'd 1781 * out because rtalloc() treats it as opaque data 1782 */ 1783 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6)); 1784 ro6->ro_dst.sin6_family = AF_INET6; 1785 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1786 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1787 rtalloc((struct route *)ro6); 1788 } 1789 } 1790 return (ro6->ro_rt); 1791 } 1792 #endif 1793 1794 #ifdef IPSEC 1795 /* compute ESP/AH header size for TCP, including outer IP header. */ 1796 size_t 1797 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1798 { 1799 struct inpcb *inp; 1800 struct mbuf *m; 1801 size_t hdrsiz; 1802 struct ip *ip; 1803 struct tcphdr *th; 1804 1805 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1806 return (0); 1807 MGETHDR(m, MB_DONTWAIT, MT_DATA); 1808 if (!m) 1809 return (0); 1810 1811 #ifdef INET6 1812 if (inp->inp_vflag & INP_IPV6) { 1813 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 1814 1815 th = (struct tcphdr *)(ip6 + 1); 1816 m->m_pkthdr.len = m->m_len = 1817 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1818 tcp_fillheaders(tp, ip6, th); 1819 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1820 } else 1821 #endif 1822 { 1823 ip = mtod(m, struct ip *); 1824 th = (struct tcphdr *)(ip + 1); 1825 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1826 tcp_fillheaders(tp, ip, th); 1827 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1828 } 1829 1830 m_free(m); 1831 return (hdrsiz); 1832 } 1833 #endif 1834 1835 /* 1836 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1837 * 1838 * This code attempts to calculate the bandwidth-delay product as a 1839 * means of determining the optimal window size to maximize bandwidth, 1840 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1841 * routers. This code also does a fairly good job keeping RTTs in check 1842 * across slow links like modems. We implement an algorithm which is very 1843 * similar (but not meant to be) TCP/Vegas. The code operates on the 1844 * transmitter side of a TCP connection and so only effects the transmit 1845 * side of the connection. 1846 * 1847 * BACKGROUND: TCP makes no provision for the management of buffer space 1848 * at the end points or at the intermediate routers and switches. A TCP 1849 * stream, whether using NewReno or not, will eventually buffer as 1850 * many packets as it is able and the only reason this typically works is 1851 * due to the fairly small default buffers made available for a connection 1852 * (typicaly 16K or 32K). As machines use larger windows and/or window 1853 * scaling it is now fairly easy for even a single TCP connection to blow-out 1854 * all available buffer space not only on the local interface, but on 1855 * intermediate routers and switches as well. NewReno makes a misguided 1856 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1857 * then backing off, then steadily increasing the window again until another 1858 * failure occurs, ad-infinitum. This results in terrible oscillation that 1859 * is only made worse as network loads increase and the idea of intentionally 1860 * blowing out network buffers is, frankly, a terrible way to manage network 1861 * resources. 1862 * 1863 * It is far better to limit the transmit window prior to the failure 1864 * condition being achieved. There are two general ways to do this: First 1865 * you can 'scan' through different transmit window sizes and locate the 1866 * point where the RTT stops increasing, indicating that you have filled the 1867 * pipe, then scan backwards until you note that RTT stops decreasing, then 1868 * repeat ad-infinitum. This method works in principle but has severe 1869 * implementation issues due to RTT variances, timer granularity, and 1870 * instability in the algorithm which can lead to many false positives and 1871 * create oscillations as well as interact badly with other TCP streams 1872 * implementing the same algorithm. 1873 * 1874 * The second method is to limit the window to the bandwidth delay product 1875 * of the link. This is the method we implement. RTT variances and our 1876 * own manipulation of the congestion window, bwnd, can potentially 1877 * destabilize the algorithm. For this reason we have to stabilize the 1878 * elements used to calculate the window. We do this by using the minimum 1879 * observed RTT, the long term average of the observed bandwidth, and 1880 * by adding two segments worth of slop. It isn't perfect but it is able 1881 * to react to changing conditions and gives us a very stable basis on 1882 * which to extend the algorithm. 1883 */ 1884 void 1885 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1886 { 1887 u_long bw; 1888 u_long bwnd; 1889 int save_ticks; 1890 int delta_ticks; 1891 1892 /* 1893 * If inflight_enable is disabled in the middle of a tcp connection, 1894 * make sure snd_bwnd is effectively disabled. 1895 */ 1896 if (!tcp_inflight_enable) { 1897 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1898 tp->snd_bandwidth = 0; 1899 return; 1900 } 1901 1902 /* 1903 * Validate the delta time. If a connection is new or has been idle 1904 * a long time we have to reset the bandwidth calculator. 1905 */ 1906 save_ticks = ticks; 1907 delta_ticks = save_ticks - tp->t_bw_rtttime; 1908 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) { 1909 tp->t_bw_rtttime = ticks; 1910 tp->t_bw_rtseq = ack_seq; 1911 if (tp->snd_bandwidth == 0) 1912 tp->snd_bandwidth = tcp_inflight_min; 1913 return; 1914 } 1915 if (delta_ticks == 0) 1916 return; 1917 1918 /* 1919 * Sanity check, plus ignore pure window update acks. 1920 */ 1921 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0) 1922 return; 1923 1924 /* 1925 * Figure out the bandwidth. Due to the tick granularity this 1926 * is a very rough number and it MUST be averaged over a fairly 1927 * long period of time. XXX we need to take into account a link 1928 * that is not using all available bandwidth, but for now our 1929 * slop will ramp us up if this case occurs and the bandwidth later 1930 * increases. 1931 */ 1932 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks; 1933 tp->t_bw_rtttime = save_ticks; 1934 tp->t_bw_rtseq = ack_seq; 1935 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1936 1937 tp->snd_bandwidth = bw; 1938 1939 /* 1940 * Calculate the semi-static bandwidth delay product, plus two maximal 1941 * segments. The additional slop puts us squarely in the sweet 1942 * spot and also handles the bandwidth run-up case. Without the 1943 * slop we could be locking ourselves into a lower bandwidth. 1944 * 1945 * Situations Handled: 1946 * (1) Prevents over-queueing of packets on LANs, especially on 1947 * high speed LANs, allowing larger TCP buffers to be 1948 * specified, and also does a good job preventing 1949 * over-queueing of packets over choke points like modems 1950 * (at least for the transmit side). 1951 * 1952 * (2) Is able to handle changing network loads (bandwidth 1953 * drops so bwnd drops, bandwidth increases so bwnd 1954 * increases). 1955 * 1956 * (3) Theoretically should stabilize in the face of multiple 1957 * connections implementing the same algorithm (this may need 1958 * a little work). 1959 * 1960 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1961 * be adjusted with a sysctl but typically only needs to be on 1962 * very slow connections. A value no smaller then 5 should 1963 * be used, but only reduce this default if you have no other 1964 * choice. 1965 */ 1966 1967 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1968 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + 1969 tcp_inflight_stab * (int)tp->t_maxseg / 10; 1970 #undef USERTT 1971 1972 if (tcp_inflight_debug > 0) { 1973 static int ltime; 1974 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1975 ltime = ticks; 1976 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1977 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd); 1978 } 1979 } 1980 if ((long)bwnd < tcp_inflight_min) 1981 bwnd = tcp_inflight_min; 1982 if (bwnd > tcp_inflight_max) 1983 bwnd = tcp_inflight_max; 1984 if ((long)bwnd < tp->t_maxseg * 2) 1985 bwnd = tp->t_maxseg * 2; 1986 tp->snd_bwnd = bwnd; 1987 } 1988