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 <machine/smp.h> 146 147 #include <sys/msgport2.h> 148 #include <sys/mplock2.h> 149 #include <net/netmsg2.h> 150 151 #if !defined(KTR_TCP) 152 #define KTR_TCP KTR_ALL 153 #endif 154 KTR_INFO_MASTER(tcp); 155 KTR_INFO(KTR_TCP, tcp, rxmsg, 0, "tcp getmsg", 0); 156 KTR_INFO(KTR_TCP, tcp, wait, 1, "tcp waitmsg", 0); 157 KTR_INFO(KTR_TCP, tcp, delayed, 2, "tcp execute delayed ops", 0); 158 #define logtcp(name) KTR_LOG(tcp_ ## name) 159 160 struct inpcbinfo tcbinfo[MAXCPU]; 161 struct tcpcbackqhead tcpcbackq[MAXCPU]; 162 163 int tcp_mpsafe_proto = 0; 164 TUNABLE_INT("net.inet.tcp.mpsafe_proto", &tcp_mpsafe_proto); 165 166 static int tcp_mpsafe_thread = NETMSG_SERVICE_ADAPTIVE; 167 TUNABLE_INT("net.inet.tcp.mpsafe_thread", &tcp_mpsafe_thread); 168 SYSCTL_INT(_net_inet_tcp, OID_AUTO, mpsafe_thread, CTLFLAG_RW, 169 &tcp_mpsafe_thread, 0, 170 "0:BGL, 1:Adaptive BGL, 2:No BGL(experimental)"); 171 172 int tcp_mssdflt = TCP_MSS; 173 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 174 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size"); 175 176 #ifdef INET6 177 int tcp_v6mssdflt = TCP6_MSS; 178 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW, 179 &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6"); 180 #endif 181 182 /* 183 * Minimum MSS we accept and use. This prevents DoS attacks where 184 * we are forced to a ridiculous low MSS like 20 and send hundreds 185 * of packets instead of one. The effect scales with the available 186 * bandwidth and quickly saturates the CPU and network interface 187 * with packet generation and sending. Set to zero to disable MINMSS 188 * checking. This setting prevents us from sending too small packets. 189 */ 190 int tcp_minmss = TCP_MINMSS; 191 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, 192 &tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); 193 194 #if 0 195 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 196 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 197 &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time"); 198 #endif 199 200 int tcp_do_rfc1323 = 1; 201 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 202 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions"); 203 204 static int tcp_tcbhashsize = 0; 205 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 206 &tcp_tcbhashsize, 0, "Size of TCP control block hashtable"); 207 208 static int do_tcpdrain = 1; 209 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 210 "Enable tcp_drain routine for extra help when low on mbufs"); 211 212 /* XXX JH */ 213 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 214 &tcbinfo[0].ipi_count, 0, "Number of active PCBs"); 215 216 static int icmp_may_rst = 1; 217 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 218 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 219 220 static int tcp_isn_reseed_interval = 0; 221 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 222 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 223 224 /* 225 * TCP bandwidth limiting sysctls. The inflight limiter is now turned on 226 * by default, but with generous values which should allow maximal 227 * bandwidth. In particular, the slop defaults to 50 (5 packets). 228 * 229 * The reason for doing this is that the limiter is the only mechanism we 230 * have which seems to do a really good job preventing receiver RX rings 231 * on network interfaces from getting blown out. Even though GigE/10GigE 232 * is supposed to flow control it looks like either it doesn't actually 233 * do it or Open Source drivers do not properly enable it. 234 * 235 * People using the limiter to reduce bottlenecks on slower WAN connections 236 * should set the slop to 20 (2 packets). 237 */ 238 static int tcp_inflight_enable = 1; 239 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW, 240 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 241 242 static int tcp_inflight_debug = 0; 243 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW, 244 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 245 246 static int tcp_inflight_min = 6144; 247 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW, 248 &tcp_inflight_min, 0, "Lower bound for TCP inflight window"); 249 250 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 251 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW, 252 &tcp_inflight_max, 0, "Upper bound for TCP inflight window"); 253 254 static int tcp_inflight_stab = 50; 255 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW, 256 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 3 packets)"); 257 258 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives"); 259 static struct malloc_pipe tcptemp_mpipe; 260 261 static void tcp_willblock(int); 262 static void tcp_notify (struct inpcb *, int); 263 264 struct tcp_stats tcpstats_percpu[MAXCPU]; 265 #ifdef SMP 266 static int 267 sysctl_tcpstats(SYSCTL_HANDLER_ARGS) 268 { 269 int cpu, error = 0; 270 271 for (cpu = 0; cpu < ncpus; ++cpu) { 272 if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu], 273 sizeof(struct tcp_stats)))) 274 break; 275 if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu], 276 sizeof(struct tcp_stats)))) 277 break; 278 } 279 280 return (error); 281 } 282 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 283 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics"); 284 #else 285 SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW, 286 &tcpstat, tcp_stats, "TCP statistics"); 287 #endif 288 289 /* 290 * Target size of TCP PCB hash tables. Must be a power of two. 291 * 292 * Note that this can be overridden by the kernel environment 293 * variable net.inet.tcp.tcbhashsize 294 */ 295 #ifndef TCBHASHSIZE 296 #define TCBHASHSIZE 512 297 #endif 298 299 /* 300 * This is the actual shape of what we allocate using the zone 301 * allocator. Doing it this way allows us to protect both structures 302 * using the same generation count, and also eliminates the overhead 303 * of allocating tcpcbs separately. By hiding the structure here, 304 * we avoid changing most of the rest of the code (although it needs 305 * to be changed, eventually, for greater efficiency). 306 */ 307 #define ALIGNMENT 32 308 #define ALIGNM1 (ALIGNMENT - 1) 309 struct inp_tp { 310 union { 311 struct inpcb inp; 312 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 313 } inp_tp_u; 314 struct tcpcb tcb; 315 struct tcp_callout inp_tp_rexmt; 316 struct tcp_callout inp_tp_persist; 317 struct tcp_callout inp_tp_keep; 318 struct tcp_callout inp_tp_2msl; 319 struct tcp_callout inp_tp_delack; 320 struct netmsg_tcp_timer inp_tp_timermsg; 321 }; 322 #undef ALIGNMENT 323 #undef ALIGNM1 324 325 /* 326 * Tcp initialization 327 */ 328 void 329 tcp_init(void) 330 { 331 struct inpcbporthead *porthashbase; 332 u_long porthashmask; 333 struct vm_zone *ipi_zone; 334 int hashsize = TCBHASHSIZE; 335 int cpu; 336 337 /* 338 * note: tcptemp is used for keepalives, and it is ok for an 339 * allocation to fail so do not specify MPF_INT. 340 */ 341 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp), 342 25, -1, 0, NULL); 343 344 tcp_delacktime = TCPTV_DELACK; 345 tcp_keepinit = TCPTV_KEEP_INIT; 346 tcp_keepidle = TCPTV_KEEP_IDLE; 347 tcp_keepintvl = TCPTV_KEEPINTVL; 348 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 349 tcp_msl = TCPTV_MSL; 350 tcp_rexmit_min = TCPTV_MIN; 351 tcp_rexmit_slop = TCPTV_CPU_VAR; 352 353 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 354 if (!powerof2(hashsize)) { 355 kprintf("WARNING: TCB hash size not a power of 2\n"); 356 hashsize = 512; /* safe default */ 357 } 358 tcp_tcbhashsize = hashsize; 359 porthashbase = hashinit(hashsize, M_PCB, &porthashmask); 360 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 361 ZONE_INTERRUPT, 0); 362 363 for (cpu = 0; cpu < ncpus2; cpu++) { 364 in_pcbinfo_init(&tcbinfo[cpu]); 365 tcbinfo[cpu].cpu = cpu; 366 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB, 367 &tcbinfo[cpu].hashmask); 368 tcbinfo[cpu].porthashbase = porthashbase; 369 tcbinfo[cpu].porthashmask = porthashmask; 370 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB, 371 &tcbinfo[cpu].wildcardhashmask); 372 tcbinfo[cpu].ipi_zone = ipi_zone; 373 TAILQ_INIT(&tcpcbackq[cpu]); 374 } 375 376 tcp_reass_maxseg = nmbclusters / 16; 377 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg); 378 379 #ifdef INET6 380 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 381 #else 382 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 383 #endif 384 if (max_protohdr < TCP_MINPROTOHDR) 385 max_protohdr = TCP_MINPROTOHDR; 386 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 387 panic("tcp_init"); 388 #undef TCP_MINPROTOHDR 389 390 /* 391 * Initialize TCP statistics counters for each CPU. 392 */ 393 #ifdef SMP 394 for (cpu = 0; cpu < ncpus; ++cpu) { 395 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats)); 396 } 397 #else 398 bzero(&tcpstat, sizeof(struct tcp_stats)); 399 #endif 400 401 syncache_init(); 402 tcp_thread_init(); 403 } 404 405 void 406 tcpmsg_service_loop(void *dummy) 407 { 408 struct netmsg *msg; 409 int mplocked; 410 411 /* 412 * Thread was started with TDF_MPSAFE 413 */ 414 mplocked = 0; 415 416 while ((msg = lwkt_waitport(&curthread->td_msgport, 0))) { 417 do { 418 logtcp(rxmsg); 419 mplocked = netmsg_service(msg, tcp_mpsafe_thread, 420 mplocked); 421 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL); 422 423 logtcp(delayed); 424 tcp_willblock(mplocked); 425 logtcp(wait); 426 } 427 } 428 429 static void 430 tcp_willblock(int mplocked) 431 { 432 struct tcpcb *tp; 433 int cpu = mycpu->gd_cpuid; 434 int unlock = 0; 435 436 if (!mplocked && !tcp_mpsafe_proto) { 437 if (TAILQ_EMPTY(&tcpcbackq[cpu])) 438 return; 439 440 get_mplock(); 441 mplocked = 1; 442 unlock = 1; 443 } 444 445 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) { 446 KKASSERT(tp->t_flags & TF_ONOUTPUTQ); 447 tp->t_flags &= ~TF_ONOUTPUTQ; 448 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq); 449 tcp_output(tp); 450 } 451 452 if (unlock) 453 rel_mplock(); 454 } 455 456 457 /* 458 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 459 * tcp_template used to store this data in mbufs, but we now recopy it out 460 * of the tcpcb each time to conserve mbufs. 461 */ 462 void 463 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr) 464 { 465 struct inpcb *inp = tp->t_inpcb; 466 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 467 468 #ifdef INET6 469 if (inp->inp_vflag & INP_IPV6) { 470 struct ip6_hdr *ip6; 471 472 ip6 = (struct ip6_hdr *)ip_ptr; 473 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 474 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 475 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 476 (IPV6_VERSION & IPV6_VERSION_MASK); 477 ip6->ip6_nxt = IPPROTO_TCP; 478 ip6->ip6_plen = sizeof(struct tcphdr); 479 ip6->ip6_src = inp->in6p_laddr; 480 ip6->ip6_dst = inp->in6p_faddr; 481 tcp_hdr->th_sum = 0; 482 } else 483 #endif 484 { 485 struct ip *ip = (struct ip *) ip_ptr; 486 487 ip->ip_vhl = IP_VHL_BORING; 488 ip->ip_tos = 0; 489 ip->ip_len = 0; 490 ip->ip_id = 0; 491 ip->ip_off = 0; 492 ip->ip_ttl = 0; 493 ip->ip_sum = 0; 494 ip->ip_p = IPPROTO_TCP; 495 ip->ip_src = inp->inp_laddr; 496 ip->ip_dst = inp->inp_faddr; 497 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, 498 ip->ip_dst.s_addr, 499 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 500 } 501 502 tcp_hdr->th_sport = inp->inp_lport; 503 tcp_hdr->th_dport = inp->inp_fport; 504 tcp_hdr->th_seq = 0; 505 tcp_hdr->th_ack = 0; 506 tcp_hdr->th_x2 = 0; 507 tcp_hdr->th_off = 5; 508 tcp_hdr->th_flags = 0; 509 tcp_hdr->th_win = 0; 510 tcp_hdr->th_urp = 0; 511 } 512 513 /* 514 * Create template to be used to send tcp packets on a connection. 515 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 516 * use for this function is in keepalives, which use tcp_respond. 517 */ 518 struct tcptemp * 519 tcp_maketemplate(struct tcpcb *tp) 520 { 521 struct tcptemp *tmp; 522 523 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL) 524 return (NULL); 525 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t); 526 return (tmp); 527 } 528 529 void 530 tcp_freetemplate(struct tcptemp *tmp) 531 { 532 mpipe_free(&tcptemp_mpipe, tmp); 533 } 534 535 /* 536 * Send a single message to the TCP at address specified by 537 * the given TCP/IP header. If m == NULL, then we make a copy 538 * of the tcpiphdr at ti and send directly to the addressed host. 539 * This is used to force keep alive messages out using the TCP 540 * template for a connection. If flags are given then we send 541 * a message back to the TCP which originated the * segment ti, 542 * and discard the mbuf containing it and any other attached mbufs. 543 * 544 * In any case the ack and sequence number of the transmitted 545 * segment are as specified by the parameters. 546 * 547 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 548 */ 549 void 550 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 551 tcp_seq ack, tcp_seq seq, int flags) 552 { 553 int tlen; 554 int win = 0; 555 struct route *ro = NULL; 556 struct route sro; 557 struct ip *ip = ipgen; 558 struct tcphdr *nth; 559 int ipflags = 0; 560 struct route_in6 *ro6 = NULL; 561 struct route_in6 sro6; 562 struct ip6_hdr *ip6 = ipgen; 563 boolean_t use_tmpro = TRUE; 564 #ifdef INET6 565 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6); 566 #else 567 const boolean_t isipv6 = FALSE; 568 #endif 569 570 if (tp != NULL) { 571 if (!(flags & TH_RST)) { 572 win = ssb_space(&tp->t_inpcb->inp_socket->so_rcv); 573 if (win < 0) 574 win = 0; 575 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 576 win = (long)TCP_MAXWIN << tp->rcv_scale; 577 } 578 /* 579 * Don't use the route cache of a listen socket, 580 * it is not MPSAFE; use temporary route cache. 581 */ 582 if (tp->t_state != TCPS_LISTEN) { 583 if (isipv6) 584 ro6 = &tp->t_inpcb->in6p_route; 585 else 586 ro = &tp->t_inpcb->inp_route; 587 use_tmpro = FALSE; 588 } 589 } 590 if (use_tmpro) { 591 if (isipv6) { 592 ro6 = &sro6; 593 bzero(ro6, sizeof *ro6); 594 } else { 595 ro = &sro; 596 bzero(ro, sizeof *ro); 597 } 598 } 599 if (m == NULL) { 600 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 601 if (m == NULL) 602 return; 603 tlen = 0; 604 m->m_data += max_linkhdr; 605 if (isipv6) { 606 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr)); 607 ip6 = mtod(m, struct ip6_hdr *); 608 nth = (struct tcphdr *)(ip6 + 1); 609 } else { 610 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); 611 ip = mtod(m, struct ip *); 612 nth = (struct tcphdr *)(ip + 1); 613 } 614 bcopy(th, nth, sizeof(struct tcphdr)); 615 flags = TH_ACK; 616 } else { 617 m_freem(m->m_next); 618 m->m_next = NULL; 619 m->m_data = (caddr_t)ipgen; 620 /* m_len is set later */ 621 tlen = 0; 622 #define xchg(a, b, type) { type t; t = a; a = b; b = t; } 623 if (isipv6) { 624 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 625 nth = (struct tcphdr *)(ip6 + 1); 626 } else { 627 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 628 nth = (struct tcphdr *)(ip + 1); 629 } 630 if (th != nth) { 631 /* 632 * this is usually a case when an extension header 633 * exists between the IPv6 header and the 634 * TCP header. 635 */ 636 nth->th_sport = th->th_sport; 637 nth->th_dport = th->th_dport; 638 } 639 xchg(nth->th_dport, nth->th_sport, n_short); 640 #undef xchg 641 } 642 if (isipv6) { 643 ip6->ip6_flow = 0; 644 ip6->ip6_vfc = IPV6_VERSION; 645 ip6->ip6_nxt = IPPROTO_TCP; 646 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen)); 647 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 648 } else { 649 tlen += sizeof(struct tcpiphdr); 650 ip->ip_len = tlen; 651 ip->ip_ttl = ip_defttl; 652 } 653 m->m_len = tlen; 654 m->m_pkthdr.len = tlen; 655 m->m_pkthdr.rcvif = NULL; 656 nth->th_seq = htonl(seq); 657 nth->th_ack = htonl(ack); 658 nth->th_x2 = 0; 659 nth->th_off = sizeof(struct tcphdr) >> 2; 660 nth->th_flags = flags; 661 if (tp != NULL) 662 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 663 else 664 nth->th_win = htons((u_short)win); 665 nth->th_urp = 0; 666 if (isipv6) { 667 nth->th_sum = 0; 668 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 669 sizeof(struct ip6_hdr), 670 tlen - sizeof(struct ip6_hdr)); 671 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 672 (ro6 && ro6->ro_rt) ? 673 ro6->ro_rt->rt_ifp : NULL); 674 } else { 675 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 676 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 677 m->m_pkthdr.csum_flags = CSUM_TCP; 678 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 679 } 680 #ifdef TCPDEBUG 681 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 682 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 683 #endif 684 if (isipv6) { 685 ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 686 tp ? tp->t_inpcb : NULL); 687 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) { 688 RTFREE(ro6->ro_rt); 689 ro6->ro_rt = NULL; 690 } 691 } else { 692 ipflags |= IP_DEBUGROUTE; 693 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 694 if ((ro == &sro) && (ro->ro_rt != NULL)) { 695 RTFREE(ro->ro_rt); 696 ro->ro_rt = NULL; 697 } 698 } 699 } 700 701 /* 702 * Create a new TCP control block, making an 703 * empty reassembly queue and hooking it to the argument 704 * protocol control block. The `inp' parameter must have 705 * come from the zone allocator set up in tcp_init(). 706 */ 707 struct tcpcb * 708 tcp_newtcpcb(struct inpcb *inp) 709 { 710 struct inp_tp *it; 711 struct tcpcb *tp; 712 #ifdef INET6 713 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 714 #else 715 const boolean_t isipv6 = FALSE; 716 #endif 717 718 it = (struct inp_tp *)inp; 719 tp = &it->tcb; 720 bzero(tp, sizeof(struct tcpcb)); 721 LIST_INIT(&tp->t_segq); 722 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt; 723 724 /* Set up our timeouts. */ 725 tp->tt_rexmt = &it->inp_tp_rexmt; 726 tp->tt_persist = &it->inp_tp_persist; 727 tp->tt_keep = &it->inp_tp_keep; 728 tp->tt_2msl = &it->inp_tp_2msl; 729 tp->tt_delack = &it->inp_tp_delack; 730 tcp_inittimers(tp); 731 732 /* 733 * Zero out timer message. We don't create it here, 734 * since the current CPU may not be the owner of this 735 * inpcb. 736 */ 737 tp->tt_msg = &it->inp_tp_timermsg; 738 bzero(tp->tt_msg, sizeof(*tp->tt_msg)); 739 740 if (tcp_do_rfc1323) 741 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP); 742 tp->t_inpcb = inp; /* XXX */ 743 tp->t_state = TCPS_CLOSED; 744 /* 745 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 746 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 747 * reasonable initial retransmit time. 748 */ 749 tp->t_srtt = TCPTV_SRTTBASE; 750 tp->t_rttvar = 751 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 752 tp->t_rttmin = tcp_rexmit_min; 753 tp->t_rxtcur = TCPTV_RTOBASE; 754 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 755 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 756 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 757 tp->t_rcvtime = ticks; 758 /* 759 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 760 * because the socket may be bound to an IPv6 wildcard address, 761 * which may match an IPv4-mapped IPv6 address. 762 */ 763 inp->inp_ip_ttl = ip_defttl; 764 inp->inp_ppcb = tp; 765 tcp_sack_tcpcb_init(tp); 766 return (tp); /* XXX */ 767 } 768 769 /* 770 * Drop a TCP connection, reporting the specified error. 771 * If connection is synchronized, then send a RST to peer. 772 */ 773 struct tcpcb * 774 tcp_drop(struct tcpcb *tp, int error) 775 { 776 struct socket *so = tp->t_inpcb->inp_socket; 777 778 if (TCPS_HAVERCVDSYN(tp->t_state)) { 779 tp->t_state = TCPS_CLOSED; 780 tcp_output(tp); 781 tcpstat.tcps_drops++; 782 } else 783 tcpstat.tcps_conndrops++; 784 if (error == ETIMEDOUT && tp->t_softerror) 785 error = tp->t_softerror; 786 so->so_error = error; 787 return (tcp_close(tp)); 788 } 789 790 #ifdef SMP 791 792 struct netmsg_remwildcard { 793 struct netmsg nm_netmsg; 794 struct inpcb *nm_inp; 795 struct inpcbinfo *nm_pcbinfo; 796 #if defined(INET6) 797 int nm_isinet6; 798 #else 799 int nm_unused01; 800 #endif 801 }; 802 803 /* 804 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the 805 * inp can be detached. We do this by cycling through the cpus, ending up 806 * on the cpu controlling the inp last and then doing the disconnect. 807 */ 808 static void 809 in_pcbremwildcardhash_handler(struct netmsg *msg0) 810 { 811 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0; 812 int cpu; 813 814 cpu = msg->nm_pcbinfo->cpu; 815 816 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) { 817 /* note: detach removes any wildcard hash entry */ 818 #ifdef INET6 819 if (msg->nm_isinet6) 820 in6_pcbdetach(msg->nm_inp); 821 else 822 #endif 823 in_pcbdetach(msg->nm_inp); 824 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0); 825 } else { 826 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo); 827 cpu = (cpu + 1) % ncpus2; 828 msg->nm_pcbinfo = &tcbinfo[cpu]; 829 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 830 } 831 } 832 833 #endif 834 835 /* 836 * Close a TCP control block: 837 * discard all space held by the tcp 838 * discard internet protocol block 839 * wake up any sleepers 840 */ 841 struct tcpcb * 842 tcp_close(struct tcpcb *tp) 843 { 844 struct tseg_qent *q; 845 struct inpcb *inp = tp->t_inpcb; 846 struct socket *so = inp->inp_socket; 847 struct rtentry *rt; 848 boolean_t dosavessthresh; 849 #ifdef SMP 850 int cpu; 851 #endif 852 #ifdef INET6 853 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 854 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0); 855 #else 856 const boolean_t isipv6 = FALSE; 857 #endif 858 859 /* 860 * The tp is not instantly destroyed in the wildcard case. Setting 861 * the state to TCPS_TERMINATING will prevent the TCP stack from 862 * messing with it, though it should be noted that this change may 863 * not take effect on other cpus until we have chained the wildcard 864 * hash removal. 865 * 866 * XXX we currently depend on the BGL to synchronize the tp->t_state 867 * update and prevent other tcp protocol threads from accepting new 868 * connections on the listen socket we might be trying to close down. 869 */ 870 KKASSERT(tp->t_state != TCPS_TERMINATING); 871 tp->t_state = TCPS_TERMINATING; 872 873 /* 874 * Make sure that all of our timers are stopped before we 875 * delete the PCB. For listen TCP socket (tp->tt_msg == NULL), 876 * timers are never used. If timer message is never created 877 * (tp->tt_msg->tt_tcb == NULL), timers are never used too. 878 */ 879 if (tp->tt_msg != NULL && tp->tt_msg->tt_tcb != NULL) { 880 tcp_callout_stop(tp, tp->tt_rexmt); 881 tcp_callout_stop(tp, tp->tt_persist); 882 tcp_callout_stop(tp, tp->tt_keep); 883 tcp_callout_stop(tp, tp->tt_2msl); 884 tcp_callout_stop(tp, tp->tt_delack); 885 } 886 887 if (tp->t_flags & TF_ONOUTPUTQ) { 888 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid); 889 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq); 890 tp->t_flags &= ~TF_ONOUTPUTQ; 891 } 892 893 /* 894 * If we got enough samples through the srtt filter, 895 * save the rtt and rttvar in the routing entry. 896 * 'Enough' is arbitrarily defined as the 16 samples. 897 * 16 samples is enough for the srtt filter to converge 898 * to within 5% of the correct value; fewer samples and 899 * we could save a very bogus rtt. 900 * 901 * Don't update the default route's characteristics and don't 902 * update anything that the user "locked". 903 */ 904 if (tp->t_rttupdated >= 16) { 905 u_long i = 0; 906 907 if (isipv6) { 908 struct sockaddr_in6 *sin6; 909 910 if ((rt = inp->in6p_route.ro_rt) == NULL) 911 goto no_valid_rt; 912 sin6 = (struct sockaddr_in6 *)rt_key(rt); 913 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 914 goto no_valid_rt; 915 } else 916 if ((rt = inp->inp_route.ro_rt) == NULL || 917 ((struct sockaddr_in *)rt_key(rt))-> 918 sin_addr.s_addr == INADDR_ANY) 919 goto no_valid_rt; 920 921 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) { 922 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 923 if (rt->rt_rmx.rmx_rtt && i) 924 /* 925 * filter this update to half the old & half 926 * the new values, converting scale. 927 * See route.h and tcp_var.h for a 928 * description of the scaling constants. 929 */ 930 rt->rt_rmx.rmx_rtt = 931 (rt->rt_rmx.rmx_rtt + i) / 2; 932 else 933 rt->rt_rmx.rmx_rtt = i; 934 tcpstat.tcps_cachedrtt++; 935 } 936 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) { 937 i = tp->t_rttvar * 938 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 939 if (rt->rt_rmx.rmx_rttvar && i) 940 rt->rt_rmx.rmx_rttvar = 941 (rt->rt_rmx.rmx_rttvar + i) / 2; 942 else 943 rt->rt_rmx.rmx_rttvar = i; 944 tcpstat.tcps_cachedrttvar++; 945 } 946 /* 947 * The old comment here said: 948 * update the pipelimit (ssthresh) if it has been updated 949 * already or if a pipesize was specified & the threshhold 950 * got below half the pipesize. I.e., wait for bad news 951 * before we start updating, then update on both good 952 * and bad news. 953 * 954 * But we want to save the ssthresh even if no pipesize is 955 * specified explicitly in the route, because such 956 * connections still have an implicit pipesize specified 957 * by the global tcp_sendspace. In the absence of a reliable 958 * way to calculate the pipesize, it will have to do. 959 */ 960 i = tp->snd_ssthresh; 961 if (rt->rt_rmx.rmx_sendpipe != 0) 962 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2); 963 else 964 dosavessthresh = (i < so->so_snd.ssb_hiwat/2); 965 if (dosavessthresh || 966 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) && 967 (rt->rt_rmx.rmx_ssthresh != 0))) { 968 /* 969 * convert the limit from user data bytes to 970 * packets then to packet data bytes. 971 */ 972 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 973 if (i < 2) 974 i = 2; 975 i *= tp->t_maxseg + 976 (isipv6 ? 977 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 978 sizeof(struct tcpiphdr)); 979 if (rt->rt_rmx.rmx_ssthresh) 980 rt->rt_rmx.rmx_ssthresh = 981 (rt->rt_rmx.rmx_ssthresh + i) / 2; 982 else 983 rt->rt_rmx.rmx_ssthresh = i; 984 tcpstat.tcps_cachedssthresh++; 985 } 986 } 987 988 no_valid_rt: 989 /* free the reassembly queue, if any */ 990 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 991 LIST_REMOVE(q, tqe_q); 992 m_freem(q->tqe_m); 993 FREE(q, M_TSEGQ); 994 tcp_reass_qsize--; 995 } 996 /* throw away SACK blocks in scoreboard*/ 997 if (TCP_DO_SACK(tp)) 998 tcp_sack_cleanup(&tp->scb); 999 1000 inp->inp_ppcb = NULL; 1001 soisdisconnected(so); 1002 1003 tcp_destroy_timermsg(tp); 1004 1005 /* 1006 * Discard the inp. In the SMP case a wildcard inp's hash (created 1007 * by a listen socket or an INADDR_ANY udp socket) is replicated 1008 * for each protocol thread and must be removed in the context of 1009 * that thread. This is accomplished by chaining the message 1010 * through the cpus. 1011 * 1012 * If the inp is not wildcarded we simply detach, which will remove 1013 * the any hashes still present for this inp. 1014 */ 1015 #ifdef SMP 1016 if (inp->inp_flags & INP_WILDCARD_MP) { 1017 struct netmsg_remwildcard *msg; 1018 1019 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2; 1020 msg = kmalloc(sizeof(struct netmsg_remwildcard), 1021 M_LWKTMSG, M_INTWAIT); 1022 netmsg_init(&msg->nm_netmsg, NULL, &netisr_afree_rport, 1023 0, in_pcbremwildcardhash_handler); 1024 #ifdef INET6 1025 msg->nm_isinet6 = isafinet6; 1026 #endif 1027 msg->nm_inp = inp; 1028 msg->nm_pcbinfo = &tcbinfo[cpu]; 1029 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1030 } else 1031 #endif 1032 { 1033 /* note: detach removes any wildcard hash entry */ 1034 #ifdef INET6 1035 if (isafinet6) 1036 in6_pcbdetach(inp); 1037 else 1038 #endif 1039 in_pcbdetach(inp); 1040 } 1041 tcpstat.tcps_closed++; 1042 return (NULL); 1043 } 1044 1045 static __inline void 1046 tcp_drain_oncpu(struct inpcbhead *head) 1047 { 1048 struct inpcb *inpb; 1049 struct tcpcb *tcpb; 1050 struct tseg_qent *te; 1051 1052 LIST_FOREACH(inpb, head, inp_list) { 1053 if (inpb->inp_flags & INP_PLACEMARKER) 1054 continue; 1055 if ((tcpb = intotcpcb(inpb))) { 1056 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) { 1057 LIST_REMOVE(te, tqe_q); 1058 m_freem(te->tqe_m); 1059 FREE(te, M_TSEGQ); 1060 tcp_reass_qsize--; 1061 } 1062 } 1063 } 1064 } 1065 1066 #ifdef SMP 1067 struct netmsg_tcp_drain { 1068 struct netmsg nm_netmsg; 1069 struct inpcbhead *nm_head; 1070 }; 1071 1072 static void 1073 tcp_drain_handler(netmsg_t netmsg) 1074 { 1075 struct netmsg_tcp_drain *nm = (void *)netmsg; 1076 1077 tcp_drain_oncpu(nm->nm_head); 1078 lwkt_replymsg(&nm->nm_netmsg.nm_lmsg, 0); 1079 } 1080 #endif 1081 1082 void 1083 tcp_drain(void) 1084 { 1085 #ifdef SMP 1086 int cpu; 1087 #endif 1088 1089 if (!do_tcpdrain) 1090 return; 1091 1092 /* 1093 * Walk the tcpbs, if existing, and flush the reassembly queue, 1094 * if there is one... 1095 * XXX: The "Net/3" implementation doesn't imply that the TCP 1096 * reassembly queue should be flushed, but in a situation 1097 * where we're really low on mbufs, this is potentially 1098 * useful. 1099 */ 1100 #ifdef SMP 1101 for (cpu = 0; cpu < ncpus2; cpu++) { 1102 struct netmsg_tcp_drain *msg; 1103 1104 if (cpu == mycpu->gd_cpuid) { 1105 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead); 1106 } else { 1107 msg = kmalloc(sizeof(struct netmsg_tcp_drain), 1108 M_LWKTMSG, M_NOWAIT); 1109 if (msg == NULL) 1110 continue; 1111 netmsg_init(&msg->nm_netmsg, NULL, &netisr_afree_rport, 1112 0, tcp_drain_handler); 1113 msg->nm_head = &tcbinfo[cpu].pcblisthead; 1114 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1115 } 1116 } 1117 #else 1118 tcp_drain_oncpu(&tcbinfo[0].pcblisthead); 1119 #endif 1120 } 1121 1122 /* 1123 * Notify a tcp user of an asynchronous error; 1124 * store error as soft error, but wake up user 1125 * (for now, won't do anything until can select for soft error). 1126 * 1127 * Do not wake up user since there currently is no mechanism for 1128 * reporting soft errors (yet - a kqueue filter may be added). 1129 */ 1130 static void 1131 tcp_notify(struct inpcb *inp, int error) 1132 { 1133 struct tcpcb *tp = intotcpcb(inp); 1134 1135 /* 1136 * Ignore some errors if we are hooked up. 1137 * If connection hasn't completed, has retransmitted several times, 1138 * and receives a second error, give up now. This is better 1139 * than waiting a long time to establish a connection that 1140 * can never complete. 1141 */ 1142 if (tp->t_state == TCPS_ESTABLISHED && 1143 (error == EHOSTUNREACH || error == ENETUNREACH || 1144 error == EHOSTDOWN)) { 1145 return; 1146 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1147 tp->t_softerror) 1148 tcp_drop(tp, error); 1149 else 1150 tp->t_softerror = error; 1151 #if 0 1152 wakeup(&so->so_timeo); 1153 sorwakeup(so); 1154 sowwakeup(so); 1155 #endif 1156 } 1157 1158 static int 1159 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1160 { 1161 int error, i, n; 1162 struct inpcb *marker; 1163 struct inpcb *inp; 1164 inp_gen_t gencnt; 1165 globaldata_t gd; 1166 int origcpu, ccpu; 1167 1168 error = 0; 1169 n = 0; 1170 1171 /* 1172 * The process of preparing the TCB list is too time-consuming and 1173 * resource-intensive to repeat twice on every request. 1174 */ 1175 if (req->oldptr == NULL) { 1176 for (ccpu = 0; ccpu < ncpus; ++ccpu) { 1177 gd = globaldata_find(ccpu); 1178 n += tcbinfo[gd->gd_cpuid].ipi_count; 1179 } 1180 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb); 1181 return (0); 1182 } 1183 1184 if (req->newptr != NULL) 1185 return (EPERM); 1186 1187 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1188 marker->inp_flags |= INP_PLACEMARKER; 1189 1190 /* 1191 * OK, now we're committed to doing something. Run the inpcb list 1192 * for each cpu in the system and construct the output. Use a 1193 * list placemarker to deal with list changes occuring during 1194 * copyout blockages (but otherwise depend on being on the correct 1195 * cpu to avoid races). 1196 */ 1197 origcpu = mycpu->gd_cpuid; 1198 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) { 1199 globaldata_t rgd; 1200 caddr_t inp_ppcb; 1201 struct xtcpcb xt; 1202 int cpu_id; 1203 1204 cpu_id = (origcpu + ccpu) % ncpus; 1205 if ((smp_active_mask & (1 << cpu_id)) == 0) 1206 continue; 1207 rgd = globaldata_find(cpu_id); 1208 lwkt_setcpu_self(rgd); 1209 1210 gencnt = tcbinfo[cpu_id].ipi_gencnt; 1211 n = tcbinfo[cpu_id].ipi_count; 1212 1213 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list); 1214 i = 0; 1215 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) { 1216 /* 1217 * process a snapshot of pcbs, ignoring placemarkers 1218 * and using our own to allow SYSCTL_OUT to block. 1219 */ 1220 LIST_REMOVE(marker, inp_list); 1221 LIST_INSERT_AFTER(inp, marker, inp_list); 1222 1223 if (inp->inp_flags & INP_PLACEMARKER) 1224 continue; 1225 if (inp->inp_gencnt > gencnt) 1226 continue; 1227 if (prison_xinpcb(req->td, inp)) 1228 continue; 1229 1230 xt.xt_len = sizeof xt; 1231 bcopy(inp, &xt.xt_inp, sizeof *inp); 1232 inp_ppcb = inp->inp_ppcb; 1233 if (inp_ppcb != NULL) 1234 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1235 else 1236 bzero(&xt.xt_tp, sizeof xt.xt_tp); 1237 if (inp->inp_socket) 1238 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1239 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0) 1240 break; 1241 ++i; 1242 } 1243 LIST_REMOVE(marker, inp_list); 1244 if (error == 0 && i < n) { 1245 bzero(&xt, sizeof xt); 1246 xt.xt_len = sizeof xt; 1247 while (i < n) { 1248 error = SYSCTL_OUT(req, &xt, sizeof xt); 1249 if (error) 1250 break; 1251 ++i; 1252 } 1253 } 1254 } 1255 1256 /* 1257 * Make sure we are on the same cpu we were on originally, since 1258 * higher level callers expect this. Also don't pollute caches with 1259 * migrated userland data by (eventually) returning to userland 1260 * on a different cpu. 1261 */ 1262 lwkt_setcpu_self(globaldata_find(origcpu)); 1263 kfree(marker, M_TEMP); 1264 return (error); 1265 } 1266 1267 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1268 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1269 1270 static int 1271 tcp_getcred(SYSCTL_HANDLER_ARGS) 1272 { 1273 struct sockaddr_in addrs[2]; 1274 struct inpcb *inp; 1275 int cpu; 1276 int error; 1277 1278 error = priv_check(req->td, PRIV_ROOT); 1279 if (error != 0) 1280 return (error); 1281 error = SYSCTL_IN(req, addrs, sizeof addrs); 1282 if (error != 0) 1283 return (error); 1284 crit_enter(); 1285 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1286 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1287 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1288 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1289 if (inp == NULL || inp->inp_socket == NULL) { 1290 error = ENOENT; 1291 goto out; 1292 } 1293 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1294 out: 1295 crit_exit(); 1296 return (error); 1297 } 1298 1299 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1300 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1301 1302 #ifdef INET6 1303 static int 1304 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1305 { 1306 struct sockaddr_in6 addrs[2]; 1307 struct inpcb *inp; 1308 int error; 1309 boolean_t mapped = FALSE; 1310 1311 error = priv_check(req->td, PRIV_ROOT); 1312 if (error != 0) 1313 return (error); 1314 error = SYSCTL_IN(req, addrs, sizeof addrs); 1315 if (error != 0) 1316 return (error); 1317 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1318 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1319 mapped = TRUE; 1320 else 1321 return (EINVAL); 1322 } 1323 crit_enter(); 1324 if (mapped) { 1325 inp = in_pcblookup_hash(&tcbinfo[0], 1326 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1327 addrs[1].sin6_port, 1328 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1329 addrs[0].sin6_port, 1330 0, NULL); 1331 } else { 1332 inp = in6_pcblookup_hash(&tcbinfo[0], 1333 &addrs[1].sin6_addr, addrs[1].sin6_port, 1334 &addrs[0].sin6_addr, addrs[0].sin6_port, 1335 0, NULL); 1336 } 1337 if (inp == NULL || inp->inp_socket == NULL) { 1338 error = ENOENT; 1339 goto out; 1340 } 1341 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1342 out: 1343 crit_exit(); 1344 return (error); 1345 } 1346 1347 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1348 0, 0, 1349 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1350 #endif 1351 1352 struct netmsg_tcp_notify { 1353 struct netmsg nm_nmsg; 1354 void (*nm_notify)(struct inpcb *, int); 1355 struct in_addr nm_faddr; 1356 int nm_arg; 1357 }; 1358 1359 static void 1360 tcp_notifyall_oncpu(struct netmsg *netmsg) 1361 { 1362 struct netmsg_tcp_notify *nmsg = (struct netmsg_tcp_notify *)netmsg; 1363 int nextcpu; 1364 1365 in_pcbnotifyall(&tcbinfo[mycpuid].pcblisthead, nmsg->nm_faddr, 1366 nmsg->nm_arg, nmsg->nm_notify); 1367 1368 nextcpu = mycpuid + 1; 1369 if (nextcpu < ncpus2) 1370 lwkt_forwardmsg(tcp_cport(nextcpu), &netmsg->nm_lmsg); 1371 else 1372 lwkt_replymsg(&netmsg->nm_lmsg, 0); 1373 } 1374 1375 void 1376 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1377 { 1378 struct ip *ip = vip; 1379 struct tcphdr *th; 1380 struct in_addr faddr; 1381 struct inpcb *inp; 1382 struct tcpcb *tp; 1383 void (*notify)(struct inpcb *, int) = tcp_notify; 1384 tcp_seq icmpseq; 1385 int arg, cpu; 1386 1387 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) { 1388 return; 1389 } 1390 1391 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1392 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1393 return; 1394 1395 arg = inetctlerrmap[cmd]; 1396 if (cmd == PRC_QUENCH) { 1397 notify = tcp_quench; 1398 } else if (icmp_may_rst && 1399 (cmd == PRC_UNREACH_ADMIN_PROHIB || 1400 cmd == PRC_UNREACH_PORT || 1401 cmd == PRC_TIMXCEED_INTRANS) && 1402 ip != NULL) { 1403 notify = tcp_drop_syn_sent; 1404 } else if (cmd == PRC_MSGSIZE) { 1405 struct icmp *icmp = (struct icmp *) 1406 ((caddr_t)ip - offsetof(struct icmp, icmp_ip)); 1407 1408 arg = ntohs(icmp->icmp_nextmtu); 1409 notify = tcp_mtudisc; 1410 } else if (PRC_IS_REDIRECT(cmd)) { 1411 ip = NULL; 1412 notify = in_rtchange; 1413 } else if (cmd == PRC_HOSTDEAD) { 1414 ip = NULL; 1415 } 1416 1417 if (ip != NULL) { 1418 crit_enter(); 1419 th = (struct tcphdr *)((caddr_t)ip + 1420 (IP_VHL_HL(ip->ip_vhl) << 2)); 1421 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1422 ip->ip_src.s_addr, th->th_sport); 1423 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1424 ip->ip_src, th->th_sport, 0, NULL); 1425 if ((inp != NULL) && (inp->inp_socket != NULL)) { 1426 icmpseq = htonl(th->th_seq); 1427 tp = intotcpcb(inp); 1428 if (SEQ_GEQ(icmpseq, tp->snd_una) && 1429 SEQ_LT(icmpseq, tp->snd_max)) 1430 (*notify)(inp, arg); 1431 } else { 1432 struct in_conninfo inc; 1433 1434 inc.inc_fport = th->th_dport; 1435 inc.inc_lport = th->th_sport; 1436 inc.inc_faddr = faddr; 1437 inc.inc_laddr = ip->ip_src; 1438 #ifdef INET6 1439 inc.inc_isipv6 = 0; 1440 #endif 1441 syncache_unreach(&inc, th); 1442 } 1443 crit_exit(); 1444 } else { 1445 struct netmsg_tcp_notify nmsg; 1446 1447 KKASSERT(&curthread->td_msgport == cpu_portfn(0)); 1448 netmsg_init(&nmsg.nm_nmsg, NULL, &curthread->td_msgport, 1449 0, tcp_notifyall_oncpu); 1450 nmsg.nm_faddr = faddr; 1451 nmsg.nm_arg = arg; 1452 nmsg.nm_notify = notify; 1453 1454 lwkt_domsg(tcp_cport(0), &nmsg.nm_nmsg.nm_lmsg, 0); 1455 } 1456 } 1457 1458 #ifdef INET6 1459 void 1460 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1461 { 1462 struct tcphdr th; 1463 void (*notify) (struct inpcb *, int) = tcp_notify; 1464 struct ip6_hdr *ip6; 1465 struct mbuf *m; 1466 struct ip6ctlparam *ip6cp = NULL; 1467 const struct sockaddr_in6 *sa6_src = NULL; 1468 int off; 1469 struct tcp_portonly { 1470 u_int16_t th_sport; 1471 u_int16_t th_dport; 1472 } *thp; 1473 int arg; 1474 1475 if (sa->sa_family != AF_INET6 || 1476 sa->sa_len != sizeof(struct sockaddr_in6)) 1477 return; 1478 1479 arg = 0; 1480 if (cmd == PRC_QUENCH) 1481 notify = tcp_quench; 1482 else if (cmd == PRC_MSGSIZE) { 1483 struct ip6ctlparam *ip6cp = d; 1484 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6; 1485 1486 arg = ntohl(icmp6->icmp6_mtu); 1487 notify = tcp_mtudisc; 1488 } else if (!PRC_IS_REDIRECT(cmd) && 1489 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) { 1490 return; 1491 } 1492 1493 /* if the parameter is from icmp6, decode it. */ 1494 if (d != NULL) { 1495 ip6cp = (struct ip6ctlparam *)d; 1496 m = ip6cp->ip6c_m; 1497 ip6 = ip6cp->ip6c_ip6; 1498 off = ip6cp->ip6c_off; 1499 sa6_src = ip6cp->ip6c_src; 1500 } else { 1501 m = NULL; 1502 ip6 = NULL; 1503 off = 0; /* fool gcc */ 1504 sa6_src = &sa6_any; 1505 } 1506 1507 if (ip6 != NULL) { 1508 struct in_conninfo inc; 1509 /* 1510 * XXX: We assume that when IPV6 is non NULL, 1511 * M and OFF are valid. 1512 */ 1513 1514 /* check if we can safely examine src and dst ports */ 1515 if (m->m_pkthdr.len < off + sizeof *thp) 1516 return; 1517 1518 bzero(&th, sizeof th); 1519 m_copydata(m, off, sizeof *thp, (caddr_t)&th); 1520 1521 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport, 1522 (struct sockaddr *)ip6cp->ip6c_src, 1523 th.th_sport, cmd, arg, notify); 1524 1525 inc.inc_fport = th.th_dport; 1526 inc.inc_lport = th.th_sport; 1527 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1528 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1529 inc.inc_isipv6 = 1; 1530 syncache_unreach(&inc, &th); 1531 } else 1532 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0, 1533 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify); 1534 } 1535 #endif 1536 1537 /* 1538 * Following is where TCP initial sequence number generation occurs. 1539 * 1540 * There are two places where we must use initial sequence numbers: 1541 * 1. In SYN-ACK packets. 1542 * 2. In SYN packets. 1543 * 1544 * All ISNs for SYN-ACK packets are generated by the syncache. See 1545 * tcp_syncache.c for details. 1546 * 1547 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1548 * depends on this property. In addition, these ISNs should be 1549 * unguessable so as to prevent connection hijacking. To satisfy 1550 * the requirements of this situation, the algorithm outlined in 1551 * RFC 1948 is used to generate sequence numbers. 1552 * 1553 * Implementation details: 1554 * 1555 * Time is based off the system timer, and is corrected so that it 1556 * increases by one megabyte per second. This allows for proper 1557 * recycling on high speed LANs while still leaving over an hour 1558 * before rollover. 1559 * 1560 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1561 * between seeding of isn_secret. This is normally set to zero, 1562 * as reseeding should not be necessary. 1563 * 1564 */ 1565 1566 #define ISN_BYTES_PER_SECOND 1048576 1567 1568 u_char isn_secret[32]; 1569 int isn_last_reseed; 1570 MD5_CTX isn_ctx; 1571 1572 tcp_seq 1573 tcp_new_isn(struct tcpcb *tp) 1574 { 1575 u_int32_t md5_buffer[4]; 1576 tcp_seq new_isn; 1577 1578 /* Seed if this is the first use, reseed if requested. */ 1579 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1580 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1581 < (u_int)ticks))) { 1582 read_random_unlimited(&isn_secret, sizeof isn_secret); 1583 isn_last_reseed = ticks; 1584 } 1585 1586 /* Compute the md5 hash and return the ISN. */ 1587 MD5Init(&isn_ctx); 1588 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 1589 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 1590 #ifdef INET6 1591 if (tp->t_inpcb->inp_vflag & INP_IPV6) { 1592 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1593 sizeof(struct in6_addr)); 1594 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1595 sizeof(struct in6_addr)); 1596 } else 1597 #endif 1598 { 1599 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1600 sizeof(struct in_addr)); 1601 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1602 sizeof(struct in_addr)); 1603 } 1604 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1605 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1606 new_isn = (tcp_seq) md5_buffer[0]; 1607 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1608 return (new_isn); 1609 } 1610 1611 /* 1612 * When a source quench is received, close congestion window 1613 * to one segment. We will gradually open it again as we proceed. 1614 */ 1615 void 1616 tcp_quench(struct inpcb *inp, int error) 1617 { 1618 struct tcpcb *tp = intotcpcb(inp); 1619 1620 if (tp != NULL) { 1621 tp->snd_cwnd = tp->t_maxseg; 1622 tp->snd_wacked = 0; 1623 } 1624 } 1625 1626 /* 1627 * When a specific ICMP unreachable message is received and the 1628 * connection state is SYN-SENT, drop the connection. This behavior 1629 * is controlled by the icmp_may_rst sysctl. 1630 */ 1631 void 1632 tcp_drop_syn_sent(struct inpcb *inp, int error) 1633 { 1634 struct tcpcb *tp = intotcpcb(inp); 1635 1636 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT)) 1637 tcp_drop(tp, error); 1638 } 1639 1640 /* 1641 * When a `need fragmentation' ICMP is received, update our idea of the MSS 1642 * based on the new value in the route. Also nudge TCP to send something, 1643 * since we know the packet we just sent was dropped. 1644 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1645 */ 1646 void 1647 tcp_mtudisc(struct inpcb *inp, int mtu) 1648 { 1649 struct tcpcb *tp = intotcpcb(inp); 1650 struct rtentry *rt; 1651 struct socket *so = inp->inp_socket; 1652 int maxopd, mss; 1653 #ifdef INET6 1654 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0); 1655 #else 1656 const boolean_t isipv6 = FALSE; 1657 #endif 1658 1659 if (tp == NULL) 1660 return; 1661 1662 /* 1663 * If no MTU is provided in the ICMP message, use the 1664 * next lower likely value, as specified in RFC 1191. 1665 */ 1666 if (mtu == 0) { 1667 int oldmtu; 1668 1669 oldmtu = tp->t_maxopd + 1670 (isipv6 ? 1671 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1672 sizeof(struct tcpiphdr)); 1673 mtu = ip_next_mtu(oldmtu, 0); 1674 } 1675 1676 if (isipv6) 1677 rt = tcp_rtlookup6(&inp->inp_inc); 1678 else 1679 rt = tcp_rtlookup(&inp->inp_inc); 1680 if (rt != NULL) { 1681 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu) 1682 mtu = rt->rt_rmx.rmx_mtu; 1683 1684 maxopd = mtu - 1685 (isipv6 ? 1686 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1687 sizeof(struct tcpiphdr)); 1688 1689 /* 1690 * XXX - The following conditional probably violates the TCP 1691 * spec. The problem is that, since we don't know the 1692 * other end's MSS, we are supposed to use a conservative 1693 * default. But, if we do that, then MTU discovery will 1694 * never actually take place, because the conservative 1695 * default is much less than the MTUs typically seen 1696 * on the Internet today. For the moment, we'll sweep 1697 * this under the carpet. 1698 * 1699 * The conservative default might not actually be a problem 1700 * if the only case this occurs is when sending an initial 1701 * SYN with options and data to a host we've never talked 1702 * to before. Then, they will reply with an MSS value which 1703 * will get recorded and the new parameters should get 1704 * recomputed. For Further Study. 1705 */ 1706 if (rt->rt_rmx.rmx_mssopt && rt->rt_rmx.rmx_mssopt < maxopd) 1707 maxopd = rt->rt_rmx.rmx_mssopt; 1708 } else 1709 maxopd = mtu - 1710 (isipv6 ? 1711 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1712 sizeof(struct tcpiphdr)); 1713 1714 if (tp->t_maxopd <= maxopd) 1715 return; 1716 tp->t_maxopd = maxopd; 1717 1718 mss = maxopd; 1719 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) == 1720 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1721 mss -= TCPOLEN_TSTAMP_APPA; 1722 1723 /* round down to multiple of MCLBYTES */ 1724 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */ 1725 if (mss > MCLBYTES) 1726 mss &= ~(MCLBYTES - 1); 1727 #else 1728 if (mss > MCLBYTES) 1729 mss = (mss / MCLBYTES) * MCLBYTES; 1730 #endif 1731 1732 if (so->so_snd.ssb_hiwat < mss) 1733 mss = so->so_snd.ssb_hiwat; 1734 1735 tp->t_maxseg = mss; 1736 tp->t_rtttime = 0; 1737 tp->snd_nxt = tp->snd_una; 1738 tcp_output(tp); 1739 tcpstat.tcps_mturesent++; 1740 } 1741 1742 /* 1743 * Look-up the routing entry to the peer of this inpcb. If no route 1744 * is found and it cannot be allocated the return NULL. This routine 1745 * is called by TCP routines that access the rmx structure and by tcp_mss 1746 * to get the interface MTU. 1747 */ 1748 struct rtentry * 1749 tcp_rtlookup(struct in_conninfo *inc) 1750 { 1751 struct route *ro = &inc->inc_route; 1752 1753 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) { 1754 /* No route yet, so try to acquire one */ 1755 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1756 /* 1757 * unused portions of the structure MUST be zero'd 1758 * out because rtalloc() treats it as opaque data 1759 */ 1760 bzero(&ro->ro_dst, sizeof(struct sockaddr_in)); 1761 ro->ro_dst.sa_family = AF_INET; 1762 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1763 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1764 inc->inc_faddr; 1765 rtalloc(ro); 1766 } 1767 } 1768 return (ro->ro_rt); 1769 } 1770 1771 #ifdef INET6 1772 struct rtentry * 1773 tcp_rtlookup6(struct in_conninfo *inc) 1774 { 1775 struct route_in6 *ro6 = &inc->inc6_route; 1776 1777 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) { 1778 /* No route yet, so try to acquire one */ 1779 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1780 /* 1781 * unused portions of the structure MUST be zero'd 1782 * out because rtalloc() treats it as opaque data 1783 */ 1784 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6)); 1785 ro6->ro_dst.sin6_family = AF_INET6; 1786 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1787 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1788 rtalloc((struct route *)ro6); 1789 } 1790 } 1791 return (ro6->ro_rt); 1792 } 1793 #endif 1794 1795 #ifdef IPSEC 1796 /* compute ESP/AH header size for TCP, including outer IP header. */ 1797 size_t 1798 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1799 { 1800 struct inpcb *inp; 1801 struct mbuf *m; 1802 size_t hdrsiz; 1803 struct ip *ip; 1804 struct tcphdr *th; 1805 1806 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1807 return (0); 1808 MGETHDR(m, MB_DONTWAIT, MT_DATA); 1809 if (!m) 1810 return (0); 1811 1812 #ifdef INET6 1813 if (inp->inp_vflag & INP_IPV6) { 1814 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 1815 1816 th = (struct tcphdr *)(ip6 + 1); 1817 m->m_pkthdr.len = m->m_len = 1818 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1819 tcp_fillheaders(tp, ip6, th); 1820 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1821 } else 1822 #endif 1823 { 1824 ip = mtod(m, struct ip *); 1825 th = (struct tcphdr *)(ip + 1); 1826 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1827 tcp_fillheaders(tp, ip, th); 1828 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1829 } 1830 1831 m_free(m); 1832 return (hdrsiz); 1833 } 1834 #endif 1835 1836 /* 1837 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1838 * 1839 * This code attempts to calculate the bandwidth-delay product as a 1840 * means of determining the optimal window size to maximize bandwidth, 1841 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1842 * routers. This code also does a fairly good job keeping RTTs in check 1843 * across slow links like modems. We implement an algorithm which is very 1844 * similar (but not meant to be) TCP/Vegas. The code operates on the 1845 * transmitter side of a TCP connection and so only effects the transmit 1846 * side of the connection. 1847 * 1848 * BACKGROUND: TCP makes no provision for the management of buffer space 1849 * at the end points or at the intermediate routers and switches. A TCP 1850 * stream, whether using NewReno or not, will eventually buffer as 1851 * many packets as it is able and the only reason this typically works is 1852 * due to the fairly small default buffers made available for a connection 1853 * (typicaly 16K or 32K). As machines use larger windows and/or window 1854 * scaling it is now fairly easy for even a single TCP connection to blow-out 1855 * all available buffer space not only on the local interface, but on 1856 * intermediate routers and switches as well. NewReno makes a misguided 1857 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1858 * then backing off, then steadily increasing the window again until another 1859 * failure occurs, ad-infinitum. This results in terrible oscillation that 1860 * is only made worse as network loads increase and the idea of intentionally 1861 * blowing out network buffers is, frankly, a terrible way to manage network 1862 * resources. 1863 * 1864 * It is far better to limit the transmit window prior to the failure 1865 * condition being achieved. There are two general ways to do this: First 1866 * you can 'scan' through different transmit window sizes and locate the 1867 * point where the RTT stops increasing, indicating that you have filled the 1868 * pipe, then scan backwards until you note that RTT stops decreasing, then 1869 * repeat ad-infinitum. This method works in principle but has severe 1870 * implementation issues due to RTT variances, timer granularity, and 1871 * instability in the algorithm which can lead to many false positives and 1872 * create oscillations as well as interact badly with other TCP streams 1873 * implementing the same algorithm. 1874 * 1875 * The second method is to limit the window to the bandwidth delay product 1876 * of the link. This is the method we implement. RTT variances and our 1877 * own manipulation of the congestion window, bwnd, can potentially 1878 * destabilize the algorithm. For this reason we have to stabilize the 1879 * elements used to calculate the window. We do this by using the minimum 1880 * observed RTT, the long term average of the observed bandwidth, and 1881 * by adding two segments worth of slop. It isn't perfect but it is able 1882 * to react to changing conditions and gives us a very stable basis on 1883 * which to extend the algorithm. 1884 */ 1885 void 1886 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1887 { 1888 u_long bw; 1889 u_long bwnd; 1890 int save_ticks; 1891 int delta_ticks; 1892 1893 /* 1894 * If inflight_enable is disabled in the middle of a tcp connection, 1895 * make sure snd_bwnd is effectively disabled. 1896 */ 1897 if (!tcp_inflight_enable) { 1898 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1899 tp->snd_bandwidth = 0; 1900 return; 1901 } 1902 1903 /* 1904 * Validate the delta time. If a connection is new or has been idle 1905 * a long time we have to reset the bandwidth calculator. 1906 */ 1907 save_ticks = ticks; 1908 delta_ticks = save_ticks - tp->t_bw_rtttime; 1909 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) { 1910 tp->t_bw_rtttime = ticks; 1911 tp->t_bw_rtseq = ack_seq; 1912 if (tp->snd_bandwidth == 0) 1913 tp->snd_bandwidth = tcp_inflight_min; 1914 return; 1915 } 1916 if (delta_ticks == 0) 1917 return; 1918 1919 /* 1920 * Sanity check, plus ignore pure window update acks. 1921 */ 1922 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0) 1923 return; 1924 1925 /* 1926 * Figure out the bandwidth. Due to the tick granularity this 1927 * is a very rough number and it MUST be averaged over a fairly 1928 * long period of time. XXX we need to take into account a link 1929 * that is not using all available bandwidth, but for now our 1930 * slop will ramp us up if this case occurs and the bandwidth later 1931 * increases. 1932 */ 1933 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks; 1934 tp->t_bw_rtttime = save_ticks; 1935 tp->t_bw_rtseq = ack_seq; 1936 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1937 1938 tp->snd_bandwidth = bw; 1939 1940 /* 1941 * Calculate the semi-static bandwidth delay product, plus two maximal 1942 * segments. The additional slop puts us squarely in the sweet 1943 * spot and also handles the bandwidth run-up case. Without the 1944 * slop we could be locking ourselves into a lower bandwidth. 1945 * 1946 * Situations Handled: 1947 * (1) Prevents over-queueing of packets on LANs, especially on 1948 * high speed LANs, allowing larger TCP buffers to be 1949 * specified, and also does a good job preventing 1950 * over-queueing of packets over choke points like modems 1951 * (at least for the transmit side). 1952 * 1953 * (2) Is able to handle changing network loads (bandwidth 1954 * drops so bwnd drops, bandwidth increases so bwnd 1955 * increases). 1956 * 1957 * (3) Theoretically should stabilize in the face of multiple 1958 * connections implementing the same algorithm (this may need 1959 * a little work). 1960 * 1961 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1962 * be adjusted with a sysctl but typically only needs to be on 1963 * very slow connections. A value no smaller then 5 should 1964 * be used, but only reduce this default if you have no other 1965 * choice. 1966 */ 1967 1968 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1969 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + 1970 tcp_inflight_stab * (int)tp->t_maxseg / 10; 1971 #undef USERTT 1972 1973 if (tcp_inflight_debug > 0) { 1974 static int ltime; 1975 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1976 ltime = ticks; 1977 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1978 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd); 1979 } 1980 } 1981 if ((long)bwnd < tcp_inflight_min) 1982 bwnd = tcp_inflight_min; 1983 if (bwnd > tcp_inflight_max) 1984 bwnd = tcp_inflight_max; 1985 if ((long)bwnd < tp->t_maxseg * 2) 1986 bwnd = tp->t_maxseg * 2; 1987 tp->snd_bwnd = bwnd; 1988 } 1989