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_inet.h" 73 #include "opt_inet6.h" 74 #include "opt_ipsec.h" 75 #include "opt_tcpdebug.h" 76 77 #include <sys/param.h> 78 #include <sys/systm.h> 79 #include <sys/callout.h> 80 #include <sys/kernel.h> 81 #include <sys/sysctl.h> 82 #include <sys/malloc.h> 83 #include <sys/mpipe.h> 84 #include <sys/mbuf.h> 85 #ifdef INET6 86 #include <sys/domain.h> 87 #endif 88 #include <sys/proc.h> 89 #include <sys/priv.h> 90 #include <sys/socket.h> 91 #include <sys/socketvar.h> 92 #include <sys/protosw.h> 93 #include <sys/random.h> 94 #include <sys/in_cksum.h> 95 #include <sys/ktr.h> 96 97 #include <net/route.h> 98 #include <net/if.h> 99 #include <net/netisr.h> 100 101 #define _IP_VHL 102 #include <netinet/in.h> 103 #include <netinet/in_systm.h> 104 #include <netinet/ip.h> 105 #include <netinet/ip6.h> 106 #include <netinet/in_pcb.h> 107 #include <netinet6/in6_pcb.h> 108 #include <netinet/in_var.h> 109 #include <netinet/ip_var.h> 110 #include <netinet6/ip6_var.h> 111 #include <netinet/ip_icmp.h> 112 #ifdef INET6 113 #include <netinet/icmp6.h> 114 #endif 115 #include <netinet/tcp.h> 116 #include <netinet/tcp_fsm.h> 117 #include <netinet/tcp_seq.h> 118 #include <netinet/tcp_timer.h> 119 #include <netinet/tcp_timer2.h> 120 #include <netinet/tcp_var.h> 121 #include <netinet6/tcp6_var.h> 122 #include <netinet/tcpip.h> 123 #ifdef TCPDEBUG 124 #include <netinet/tcp_debug.h> 125 #endif 126 #include <netinet6/ip6protosw.h> 127 128 #ifdef IPSEC 129 #include <netinet6/ipsec.h> 130 #include <netproto/key/key.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 static int icmp_may_rst = 1; 213 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 214 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 215 216 static int tcp_isn_reseed_interval = 0; 217 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 218 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 219 220 /* 221 * TCP bandwidth limiting sysctls. The inflight limiter is now turned on 222 * by default, but with generous values which should allow maximal 223 * bandwidth. In particular, the slop defaults to 50 (5 packets). 224 * 225 * The reason for doing this is that the limiter is the only mechanism we 226 * have which seems to do a really good job preventing receiver RX rings 227 * on network interfaces from getting blown out. Even though GigE/10GigE 228 * is supposed to flow control it looks like either it doesn't actually 229 * do it or Open Source drivers do not properly enable it. 230 * 231 * People using the limiter to reduce bottlenecks on slower WAN connections 232 * should set the slop to 20 (2 packets). 233 */ 234 static int tcp_inflight_enable = 1; 235 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW, 236 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 237 238 static int tcp_inflight_debug = 0; 239 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW, 240 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 241 242 static int tcp_inflight_min = 6144; 243 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW, 244 &tcp_inflight_min, 0, "Lower bound for TCP inflight window"); 245 246 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 247 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW, 248 &tcp_inflight_max, 0, "Upper bound for TCP inflight window"); 249 250 static int tcp_inflight_stab = 50; 251 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW, 252 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 3 packets)"); 253 254 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives"); 255 static struct malloc_pipe tcptemp_mpipe; 256 257 static void tcp_willblock(int); 258 static void tcp_notify (struct inpcb *, int); 259 260 struct tcp_stats tcpstats_percpu[MAXCPU]; 261 #ifdef SMP 262 static int 263 sysctl_tcpstats(SYSCTL_HANDLER_ARGS) 264 { 265 int cpu, error = 0; 266 267 for (cpu = 0; cpu < ncpus; ++cpu) { 268 if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu], 269 sizeof(struct tcp_stats)))) 270 break; 271 if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu], 272 sizeof(struct tcp_stats)))) 273 break; 274 } 275 276 return (error); 277 } 278 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 279 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics"); 280 #else 281 SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW, 282 &tcpstat, tcp_stats, "TCP statistics"); 283 #endif 284 285 /* 286 * Target size of TCP PCB hash tables. Must be a power of two. 287 * 288 * Note that this can be overridden by the kernel environment 289 * variable net.inet.tcp.tcbhashsize 290 */ 291 #ifndef TCBHASHSIZE 292 #define TCBHASHSIZE 512 293 #endif 294 295 /* 296 * This is the actual shape of what we allocate using the zone 297 * allocator. Doing it this way allows us to protect both structures 298 * using the same generation count, and also eliminates the overhead 299 * of allocating tcpcbs separately. By hiding the structure here, 300 * we avoid changing most of the rest of the code (although it needs 301 * to be changed, eventually, for greater efficiency). 302 */ 303 #define ALIGNMENT 32 304 #define ALIGNM1 (ALIGNMENT - 1) 305 struct inp_tp { 306 union { 307 struct inpcb inp; 308 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 309 } inp_tp_u; 310 struct tcpcb tcb; 311 struct tcp_callout inp_tp_rexmt; 312 struct tcp_callout inp_tp_persist; 313 struct tcp_callout inp_tp_keep; 314 struct tcp_callout inp_tp_2msl; 315 struct tcp_callout inp_tp_delack; 316 struct netmsg_tcp_timer inp_tp_timermsg; 317 }; 318 #undef ALIGNMENT 319 #undef ALIGNM1 320 321 /* 322 * Tcp initialization 323 */ 324 void 325 tcp_init(void) 326 { 327 struct inpcbporthead *porthashbase; 328 u_long porthashmask; 329 int hashsize = TCBHASHSIZE; 330 int cpu; 331 332 /* 333 * note: tcptemp is used for keepalives, and it is ok for an 334 * allocation to fail so do not specify MPF_INT. 335 */ 336 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp), 337 25, -1, 0, NULL); 338 339 tcp_delacktime = TCPTV_DELACK; 340 tcp_keepinit = TCPTV_KEEP_INIT; 341 tcp_keepidle = TCPTV_KEEP_IDLE; 342 tcp_keepintvl = TCPTV_KEEPINTVL; 343 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 344 tcp_msl = TCPTV_MSL; 345 tcp_rexmit_min = TCPTV_MIN; 346 tcp_rexmit_slop = TCPTV_CPU_VAR; 347 348 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 349 if (!powerof2(hashsize)) { 350 kprintf("WARNING: TCB hash size not a power of 2\n"); 351 hashsize = 512; /* safe default */ 352 } 353 tcp_tcbhashsize = hashsize; 354 porthashbase = hashinit(hashsize, M_PCB, &porthashmask); 355 356 for (cpu = 0; cpu < ncpus2; cpu++) { 357 in_pcbinfo_init(&tcbinfo[cpu]); 358 tcbinfo[cpu].cpu = cpu; 359 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB, 360 &tcbinfo[cpu].hashmask); 361 tcbinfo[cpu].porthashbase = porthashbase; 362 tcbinfo[cpu].porthashmask = porthashmask; 363 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB, 364 &tcbinfo[cpu].wildcardhashmask); 365 tcbinfo[cpu].ipi_size = sizeof(struct inp_tp); 366 TAILQ_INIT(&tcpcbackq[cpu]); 367 } 368 369 tcp_reass_maxseg = nmbclusters / 16; 370 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg); 371 372 #ifdef INET6 373 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 374 #else 375 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 376 #endif 377 if (max_protohdr < TCP_MINPROTOHDR) 378 max_protohdr = TCP_MINPROTOHDR; 379 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 380 panic("tcp_init"); 381 #undef TCP_MINPROTOHDR 382 383 /* 384 * Initialize TCP statistics counters for each CPU. 385 */ 386 #ifdef SMP 387 for (cpu = 0; cpu < ncpus; ++cpu) { 388 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats)); 389 } 390 #else 391 bzero(&tcpstat, sizeof(struct tcp_stats)); 392 #endif 393 394 syncache_init(); 395 tcp_thread_init(); 396 } 397 398 void 399 tcpmsg_service_loop(void *dummy) 400 { 401 struct netmsg *msg; 402 int mplocked; 403 404 /* 405 * Threads always start mpsafe. 406 */ 407 mplocked = 0; 408 409 while ((msg = lwkt_waitport(&curthread->td_msgport, 0))) { 410 do { 411 logtcp(rxmsg); 412 mplocked = netmsg_service(msg, tcp_mpsafe_thread, 413 mplocked); 414 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL); 415 416 logtcp(delayed); 417 tcp_willblock(mplocked); 418 logtcp(wait); 419 } 420 } 421 422 static void 423 tcp_willblock(int mplocked) 424 { 425 struct tcpcb *tp; 426 int cpu = mycpu->gd_cpuid; 427 int unlock = 0; 428 429 if (!mplocked && !tcp_mpsafe_proto) { 430 if (TAILQ_EMPTY(&tcpcbackq[cpu])) 431 return; 432 433 get_mplock(); 434 mplocked = 1; 435 unlock = 1; 436 } 437 438 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) { 439 KKASSERT(tp->t_flags & TF_ONOUTPUTQ); 440 tp->t_flags &= ~TF_ONOUTPUTQ; 441 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq); 442 tcp_output(tp); 443 } 444 445 if (unlock) 446 rel_mplock(); 447 } 448 449 450 /* 451 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 452 * tcp_template used to store this data in mbufs, but we now recopy it out 453 * of the tcpcb each time to conserve mbufs. 454 */ 455 void 456 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr) 457 { 458 struct inpcb *inp = tp->t_inpcb; 459 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 460 461 #ifdef INET6 462 if (inp->inp_vflag & INP_IPV6) { 463 struct ip6_hdr *ip6; 464 465 ip6 = (struct ip6_hdr *)ip_ptr; 466 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 467 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 468 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 469 (IPV6_VERSION & IPV6_VERSION_MASK); 470 ip6->ip6_nxt = IPPROTO_TCP; 471 ip6->ip6_plen = sizeof(struct tcphdr); 472 ip6->ip6_src = inp->in6p_laddr; 473 ip6->ip6_dst = inp->in6p_faddr; 474 tcp_hdr->th_sum = 0; 475 } else 476 #endif 477 { 478 struct ip *ip = (struct ip *) ip_ptr; 479 480 ip->ip_vhl = IP_VHL_BORING; 481 ip->ip_tos = 0; 482 ip->ip_len = 0; 483 ip->ip_id = 0; 484 ip->ip_off = 0; 485 ip->ip_ttl = 0; 486 ip->ip_sum = 0; 487 ip->ip_p = IPPROTO_TCP; 488 ip->ip_src = inp->inp_laddr; 489 ip->ip_dst = inp->inp_faddr; 490 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, 491 ip->ip_dst.s_addr, 492 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 493 } 494 495 tcp_hdr->th_sport = inp->inp_lport; 496 tcp_hdr->th_dport = inp->inp_fport; 497 tcp_hdr->th_seq = 0; 498 tcp_hdr->th_ack = 0; 499 tcp_hdr->th_x2 = 0; 500 tcp_hdr->th_off = 5; 501 tcp_hdr->th_flags = 0; 502 tcp_hdr->th_win = 0; 503 tcp_hdr->th_urp = 0; 504 } 505 506 /* 507 * Create template to be used to send tcp packets on a connection. 508 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 509 * use for this function is in keepalives, which use tcp_respond. 510 */ 511 struct tcptemp * 512 tcp_maketemplate(struct tcpcb *tp) 513 { 514 struct tcptemp *tmp; 515 516 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL) 517 return (NULL); 518 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t); 519 return (tmp); 520 } 521 522 void 523 tcp_freetemplate(struct tcptemp *tmp) 524 { 525 mpipe_free(&tcptemp_mpipe, tmp); 526 } 527 528 /* 529 * Send a single message to the TCP at address specified by 530 * the given TCP/IP header. If m == NULL, then we make a copy 531 * of the tcpiphdr at ti and send directly to the addressed host. 532 * This is used to force keep alive messages out using the TCP 533 * template for a connection. If flags are given then we send 534 * a message back to the TCP which originated the * segment ti, 535 * and discard the mbuf containing it and any other attached mbufs. 536 * 537 * In any case the ack and sequence number of the transmitted 538 * segment are as specified by the parameters. 539 * 540 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 541 */ 542 void 543 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 544 tcp_seq ack, tcp_seq seq, int flags) 545 { 546 int tlen; 547 int win = 0; 548 struct route *ro = NULL; 549 struct route sro; 550 struct ip *ip = ipgen; 551 struct tcphdr *nth; 552 int ipflags = 0; 553 struct route_in6 *ro6 = NULL; 554 struct route_in6 sro6; 555 struct ip6_hdr *ip6 = ipgen; 556 boolean_t use_tmpro = TRUE; 557 #ifdef INET6 558 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6); 559 #else 560 const boolean_t isipv6 = FALSE; 561 #endif 562 563 if (tp != NULL) { 564 if (!(flags & TH_RST)) { 565 win = ssb_space(&tp->t_inpcb->inp_socket->so_rcv); 566 if (win < 0) 567 win = 0; 568 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 569 win = (long)TCP_MAXWIN << tp->rcv_scale; 570 } 571 /* 572 * Don't use the route cache of a listen socket, 573 * it is not MPSAFE; use temporary route cache. 574 */ 575 if (tp->t_state != TCPS_LISTEN) { 576 if (isipv6) 577 ro6 = &tp->t_inpcb->in6p_route; 578 else 579 ro = &tp->t_inpcb->inp_route; 580 use_tmpro = FALSE; 581 } 582 } 583 if (use_tmpro) { 584 if (isipv6) { 585 ro6 = &sro6; 586 bzero(ro6, sizeof *ro6); 587 } else { 588 ro = &sro; 589 bzero(ro, sizeof *ro); 590 } 591 } 592 if (m == NULL) { 593 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 594 if (m == NULL) 595 return; 596 tlen = 0; 597 m->m_data += max_linkhdr; 598 if (isipv6) { 599 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr)); 600 ip6 = mtod(m, struct ip6_hdr *); 601 nth = (struct tcphdr *)(ip6 + 1); 602 } else { 603 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); 604 ip = mtod(m, struct ip *); 605 nth = (struct tcphdr *)(ip + 1); 606 } 607 bcopy(th, nth, sizeof(struct tcphdr)); 608 flags = TH_ACK; 609 } else { 610 m_freem(m->m_next); 611 m->m_next = NULL; 612 m->m_data = (caddr_t)ipgen; 613 /* m_len is set later */ 614 tlen = 0; 615 #define xchg(a, b, type) { type t; t = a; a = b; b = t; } 616 if (isipv6) { 617 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 618 nth = (struct tcphdr *)(ip6 + 1); 619 } else { 620 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 621 nth = (struct tcphdr *)(ip + 1); 622 } 623 if (th != nth) { 624 /* 625 * this is usually a case when an extension header 626 * exists between the IPv6 header and the 627 * TCP header. 628 */ 629 nth->th_sport = th->th_sport; 630 nth->th_dport = th->th_dport; 631 } 632 xchg(nth->th_dport, nth->th_sport, n_short); 633 #undef xchg 634 } 635 if (isipv6) { 636 ip6->ip6_flow = 0; 637 ip6->ip6_vfc = IPV6_VERSION; 638 ip6->ip6_nxt = IPPROTO_TCP; 639 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen)); 640 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 641 } else { 642 tlen += sizeof(struct tcpiphdr); 643 ip->ip_len = tlen; 644 ip->ip_ttl = ip_defttl; 645 } 646 m->m_len = tlen; 647 m->m_pkthdr.len = tlen; 648 m->m_pkthdr.rcvif = NULL; 649 nth->th_seq = htonl(seq); 650 nth->th_ack = htonl(ack); 651 nth->th_x2 = 0; 652 nth->th_off = sizeof(struct tcphdr) >> 2; 653 nth->th_flags = flags; 654 if (tp != NULL) 655 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 656 else 657 nth->th_win = htons((u_short)win); 658 nth->th_urp = 0; 659 if (isipv6) { 660 nth->th_sum = 0; 661 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 662 sizeof(struct ip6_hdr), 663 tlen - sizeof(struct ip6_hdr)); 664 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 665 (ro6 && ro6->ro_rt) ? 666 ro6->ro_rt->rt_ifp : NULL); 667 } else { 668 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 669 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 670 m->m_pkthdr.csum_flags = CSUM_TCP; 671 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 672 } 673 #ifdef TCPDEBUG 674 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 675 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 676 #endif 677 if (isipv6) { 678 ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 679 tp ? tp->t_inpcb : NULL); 680 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) { 681 RTFREE(ro6->ro_rt); 682 ro6->ro_rt = NULL; 683 } 684 } else { 685 ipflags |= IP_DEBUGROUTE; 686 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 687 if ((ro == &sro) && (ro->ro_rt != NULL)) { 688 RTFREE(ro->ro_rt); 689 ro->ro_rt = NULL; 690 } 691 } 692 } 693 694 /* 695 * Create a new TCP control block, making an 696 * empty reassembly queue and hooking it to the argument 697 * protocol control block. The `inp' parameter must have 698 * come from the zone allocator set up in tcp_init(). 699 */ 700 struct tcpcb * 701 tcp_newtcpcb(struct inpcb *inp) 702 { 703 struct inp_tp *it; 704 struct tcpcb *tp; 705 #ifdef INET6 706 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 707 #else 708 const boolean_t isipv6 = FALSE; 709 #endif 710 711 it = (struct inp_tp *)inp; 712 tp = &it->tcb; 713 bzero(tp, sizeof(struct tcpcb)); 714 LIST_INIT(&tp->t_segq); 715 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt; 716 717 /* Set up our timeouts. */ 718 tp->tt_rexmt = &it->inp_tp_rexmt; 719 tp->tt_persist = &it->inp_tp_persist; 720 tp->tt_keep = &it->inp_tp_keep; 721 tp->tt_2msl = &it->inp_tp_2msl; 722 tp->tt_delack = &it->inp_tp_delack; 723 tcp_inittimers(tp); 724 725 /* 726 * Zero out timer message. We don't create it here, 727 * since the current CPU may not be the owner of this 728 * inpcb. 729 */ 730 tp->tt_msg = &it->inp_tp_timermsg; 731 bzero(tp->tt_msg, sizeof(*tp->tt_msg)); 732 733 if (tcp_do_rfc1323) 734 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP); 735 tp->t_inpcb = inp; /* XXX */ 736 tp->t_state = TCPS_CLOSED; 737 /* 738 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 739 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 740 * reasonable initial retransmit time. 741 */ 742 tp->t_srtt = TCPTV_SRTTBASE; 743 tp->t_rttvar = 744 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 745 tp->t_rttmin = tcp_rexmit_min; 746 tp->t_rxtcur = TCPTV_RTOBASE; 747 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 748 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 749 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 750 tp->t_rcvtime = ticks; 751 /* 752 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 753 * because the socket may be bound to an IPv6 wildcard address, 754 * which may match an IPv4-mapped IPv6 address. 755 */ 756 inp->inp_ip_ttl = ip_defttl; 757 inp->inp_ppcb = tp; 758 tcp_sack_tcpcb_init(tp); 759 return (tp); /* XXX */ 760 } 761 762 /* 763 * Drop a TCP connection, reporting the specified error. 764 * If connection is synchronized, then send a RST to peer. 765 */ 766 struct tcpcb * 767 tcp_drop(struct tcpcb *tp, int error) 768 { 769 struct socket *so = tp->t_inpcb->inp_socket; 770 771 if (TCPS_HAVERCVDSYN(tp->t_state)) { 772 tp->t_state = TCPS_CLOSED; 773 tcp_output(tp); 774 tcpstat.tcps_drops++; 775 } else 776 tcpstat.tcps_conndrops++; 777 if (error == ETIMEDOUT && tp->t_softerror) 778 error = tp->t_softerror; 779 so->so_error = error; 780 return (tcp_close(tp)); 781 } 782 783 #ifdef SMP 784 785 struct netmsg_remwildcard { 786 struct netmsg nm_netmsg; 787 struct inpcb *nm_inp; 788 struct inpcbinfo *nm_pcbinfo; 789 #if defined(INET6) 790 int nm_isinet6; 791 #else 792 int nm_unused01; 793 #endif 794 }; 795 796 /* 797 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the 798 * inp can be detached. We do this by cycling through the cpus, ending up 799 * on the cpu controlling the inp last and then doing the disconnect. 800 */ 801 static void 802 in_pcbremwildcardhash_handler(struct netmsg *msg0) 803 { 804 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0; 805 int cpu; 806 807 cpu = msg->nm_pcbinfo->cpu; 808 809 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) { 810 /* note: detach removes any wildcard hash entry */ 811 #ifdef INET6 812 if (msg->nm_isinet6) 813 in6_pcbdetach(msg->nm_inp); 814 else 815 #endif 816 in_pcbdetach(msg->nm_inp); 817 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0); 818 } else { 819 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo); 820 cpu = (cpu + 1) % ncpus2; 821 msg->nm_pcbinfo = &tcbinfo[cpu]; 822 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 823 } 824 } 825 826 #endif 827 828 /* 829 * Close a TCP control block: 830 * discard all space held by the tcp 831 * discard internet protocol block 832 * wake up any sleepers 833 */ 834 struct tcpcb * 835 tcp_close(struct tcpcb *tp) 836 { 837 struct tseg_qent *q; 838 struct inpcb *inp = tp->t_inpcb; 839 struct socket *so = inp->inp_socket; 840 struct rtentry *rt; 841 boolean_t dosavessthresh; 842 #ifdef SMP 843 int cpu; 844 #endif 845 #ifdef INET6 846 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 847 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0); 848 #else 849 const boolean_t isipv6 = FALSE; 850 #endif 851 852 /* 853 * The tp is not instantly destroyed in the wildcard case. Setting 854 * the state to TCPS_TERMINATING will prevent the TCP stack from 855 * messing with it, though it should be noted that this change may 856 * not take effect on other cpus until we have chained the wildcard 857 * hash removal. 858 * 859 * XXX we currently depend on the BGL to synchronize the tp->t_state 860 * update and prevent other tcp protocol threads from accepting new 861 * connections on the listen socket we might be trying to close down. 862 */ 863 KKASSERT(tp->t_state != TCPS_TERMINATING); 864 tp->t_state = TCPS_TERMINATING; 865 866 /* 867 * Make sure that all of our timers are stopped before we 868 * delete the PCB. For listen TCP socket (tp->tt_msg == NULL), 869 * timers are never used. If timer message is never created 870 * (tp->tt_msg->tt_tcb == NULL), timers are never used too. 871 */ 872 if (tp->tt_msg != NULL && tp->tt_msg->tt_tcb != NULL) { 873 tcp_callout_stop(tp, tp->tt_rexmt); 874 tcp_callout_stop(tp, tp->tt_persist); 875 tcp_callout_stop(tp, tp->tt_keep); 876 tcp_callout_stop(tp, tp->tt_2msl); 877 tcp_callout_stop(tp, tp->tt_delack); 878 } 879 880 if (tp->t_flags & TF_ONOUTPUTQ) { 881 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid); 882 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq); 883 tp->t_flags &= ~TF_ONOUTPUTQ; 884 } 885 886 /* 887 * If we got enough samples through the srtt filter, 888 * save the rtt and rttvar in the routing entry. 889 * 'Enough' is arbitrarily defined as the 16 samples. 890 * 16 samples is enough for the srtt filter to converge 891 * to within 5% of the correct value; fewer samples and 892 * we could save a very bogus rtt. 893 * 894 * Don't update the default route's characteristics and don't 895 * update anything that the user "locked". 896 */ 897 if (tp->t_rttupdated >= 16) { 898 u_long i = 0; 899 900 if (isipv6) { 901 struct sockaddr_in6 *sin6; 902 903 if ((rt = inp->in6p_route.ro_rt) == NULL) 904 goto no_valid_rt; 905 sin6 = (struct sockaddr_in6 *)rt_key(rt); 906 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 907 goto no_valid_rt; 908 } else 909 if ((rt = inp->inp_route.ro_rt) == NULL || 910 ((struct sockaddr_in *)rt_key(rt))-> 911 sin_addr.s_addr == INADDR_ANY) 912 goto no_valid_rt; 913 914 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) { 915 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 916 if (rt->rt_rmx.rmx_rtt && i) 917 /* 918 * filter this update to half the old & half 919 * the new values, converting scale. 920 * See route.h and tcp_var.h for a 921 * description of the scaling constants. 922 */ 923 rt->rt_rmx.rmx_rtt = 924 (rt->rt_rmx.rmx_rtt + i) / 2; 925 else 926 rt->rt_rmx.rmx_rtt = i; 927 tcpstat.tcps_cachedrtt++; 928 } 929 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) { 930 i = tp->t_rttvar * 931 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 932 if (rt->rt_rmx.rmx_rttvar && i) 933 rt->rt_rmx.rmx_rttvar = 934 (rt->rt_rmx.rmx_rttvar + i) / 2; 935 else 936 rt->rt_rmx.rmx_rttvar = i; 937 tcpstat.tcps_cachedrttvar++; 938 } 939 /* 940 * The old comment here said: 941 * update the pipelimit (ssthresh) if it has been updated 942 * already or if a pipesize was specified & the threshhold 943 * got below half the pipesize. I.e., wait for bad news 944 * before we start updating, then update on both good 945 * and bad news. 946 * 947 * But we want to save the ssthresh even if no pipesize is 948 * specified explicitly in the route, because such 949 * connections still have an implicit pipesize specified 950 * by the global tcp_sendspace. In the absence of a reliable 951 * way to calculate the pipesize, it will have to do. 952 */ 953 i = tp->snd_ssthresh; 954 if (rt->rt_rmx.rmx_sendpipe != 0) 955 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2); 956 else 957 dosavessthresh = (i < so->so_snd.ssb_hiwat/2); 958 if (dosavessthresh || 959 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) && 960 (rt->rt_rmx.rmx_ssthresh != 0))) { 961 /* 962 * convert the limit from user data bytes to 963 * packets then to packet data bytes. 964 */ 965 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 966 if (i < 2) 967 i = 2; 968 i *= tp->t_maxseg + 969 (isipv6 ? 970 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 971 sizeof(struct tcpiphdr)); 972 if (rt->rt_rmx.rmx_ssthresh) 973 rt->rt_rmx.rmx_ssthresh = 974 (rt->rt_rmx.rmx_ssthresh + i) / 2; 975 else 976 rt->rt_rmx.rmx_ssthresh = i; 977 tcpstat.tcps_cachedssthresh++; 978 } 979 } 980 981 no_valid_rt: 982 /* free the reassembly queue, if any */ 983 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 984 LIST_REMOVE(q, tqe_q); 985 m_freem(q->tqe_m); 986 FREE(q, M_TSEGQ); 987 atomic_add_int(&tcp_reass_qsize, -1); 988 } 989 /* throw away SACK blocks in scoreboard*/ 990 if (TCP_DO_SACK(tp)) 991 tcp_sack_cleanup(&tp->scb); 992 993 inp->inp_ppcb = NULL; 994 soisdisconnected(so); 995 996 tcp_destroy_timermsg(tp); 997 if (tp->t_flags & TF_SYNCACHE) 998 syncache_destroy(tp); 999 1000 /* 1001 * Discard the inp. In the SMP case a wildcard inp's hash (created 1002 * by a listen socket or an INADDR_ANY udp socket) is replicated 1003 * for each protocol thread and must be removed in the context of 1004 * that thread. This is accomplished by chaining the message 1005 * through the cpus. 1006 * 1007 * If the inp is not wildcarded we simply detach, which will remove 1008 * the any hashes still present for this inp. 1009 */ 1010 #ifdef SMP 1011 if (inp->inp_flags & INP_WILDCARD_MP) { 1012 struct netmsg_remwildcard *msg; 1013 1014 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2; 1015 msg = kmalloc(sizeof(struct netmsg_remwildcard), 1016 M_LWKTMSG, M_INTWAIT); 1017 netmsg_init(&msg->nm_netmsg, NULL, &netisr_afree_rport, 1018 0, in_pcbremwildcardhash_handler); 1019 #ifdef INET6 1020 msg->nm_isinet6 = isafinet6; 1021 #endif 1022 msg->nm_inp = inp; 1023 msg->nm_pcbinfo = &tcbinfo[cpu]; 1024 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1025 } else 1026 #endif 1027 { 1028 /* note: detach removes any wildcard hash entry */ 1029 #ifdef INET6 1030 if (isafinet6) 1031 in6_pcbdetach(inp); 1032 else 1033 #endif 1034 in_pcbdetach(inp); 1035 } 1036 tcpstat.tcps_closed++; 1037 return (NULL); 1038 } 1039 1040 static __inline void 1041 tcp_drain_oncpu(struct inpcbhead *head) 1042 { 1043 struct inpcb *marker; 1044 struct inpcb *inpb; 1045 struct tcpcb *tcpb; 1046 struct tseg_qent *te; 1047 1048 /* 1049 * Allows us to block while running the list 1050 */ 1051 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1052 marker->inp_flags |= INP_PLACEMARKER; 1053 LIST_INSERT_HEAD(head, marker, inp_list); 1054 1055 while ((inpb = LIST_NEXT(marker, inp_list)) != NULL) { 1056 if ((inpb->inp_flags & INP_PLACEMARKER) == 0 && 1057 (tcpb = intotcpcb(inpb)) != NULL && 1058 (te = LIST_FIRST(&tcpb->t_segq)) != NULL) { 1059 LIST_REMOVE(te, tqe_q); 1060 m_freem(te->tqe_m); 1061 FREE(te, M_TSEGQ); 1062 atomic_add_int(&tcp_reass_qsize, -1); 1063 /* retry */ 1064 } else { 1065 LIST_REMOVE(marker, inp_list); 1066 LIST_INSERT_AFTER(inpb, marker, inp_list); 1067 } 1068 } 1069 LIST_REMOVE(marker, inp_list); 1070 kfree(marker, M_TEMP); 1071 } 1072 1073 #ifdef SMP 1074 struct netmsg_tcp_drain { 1075 struct netmsg nm_netmsg; 1076 struct inpcbhead *nm_head; 1077 }; 1078 1079 static void 1080 tcp_drain_handler(netmsg_t netmsg) 1081 { 1082 struct netmsg_tcp_drain *nm = (void *)netmsg; 1083 1084 tcp_drain_oncpu(nm->nm_head); 1085 lwkt_replymsg(&nm->nm_netmsg.nm_lmsg, 0); 1086 } 1087 #endif 1088 1089 void 1090 tcp_drain(void) 1091 { 1092 #ifdef SMP 1093 int cpu; 1094 #endif 1095 1096 if (!do_tcpdrain) 1097 return; 1098 1099 /* 1100 * Walk the tcpbs, if existing, and flush the reassembly queue, 1101 * if there is one... 1102 * XXX: The "Net/3" implementation doesn't imply that the TCP 1103 * reassembly queue should be flushed, but in a situation 1104 * where we're really low on mbufs, this is potentially 1105 * useful. 1106 */ 1107 #ifdef SMP 1108 for (cpu = 0; cpu < ncpus2; cpu++) { 1109 struct netmsg_tcp_drain *msg; 1110 1111 if (cpu == mycpu->gd_cpuid) { 1112 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead); 1113 } else { 1114 msg = kmalloc(sizeof(struct netmsg_tcp_drain), 1115 M_LWKTMSG, M_NOWAIT); 1116 if (msg == NULL) 1117 continue; 1118 netmsg_init(&msg->nm_netmsg, NULL, &netisr_afree_rport, 1119 0, tcp_drain_handler); 1120 msg->nm_head = &tcbinfo[cpu].pcblisthead; 1121 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1122 } 1123 } 1124 #else 1125 tcp_drain_oncpu(&tcbinfo[0].pcblisthead); 1126 #endif 1127 } 1128 1129 /* 1130 * Notify a tcp user of an asynchronous error; 1131 * store error as soft error, but wake up user 1132 * (for now, won't do anything until can select for soft error). 1133 * 1134 * Do not wake up user since there currently is no mechanism for 1135 * reporting soft errors (yet - a kqueue filter may be added). 1136 */ 1137 static void 1138 tcp_notify(struct inpcb *inp, int error) 1139 { 1140 struct tcpcb *tp = intotcpcb(inp); 1141 1142 /* 1143 * Ignore some errors if we are hooked up. 1144 * If connection hasn't completed, has retransmitted several times, 1145 * and receives a second error, give up now. This is better 1146 * than waiting a long time to establish a connection that 1147 * can never complete. 1148 */ 1149 if (tp->t_state == TCPS_ESTABLISHED && 1150 (error == EHOSTUNREACH || error == ENETUNREACH || 1151 error == EHOSTDOWN)) { 1152 return; 1153 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1154 tp->t_softerror) 1155 tcp_drop(tp, error); 1156 else 1157 tp->t_softerror = error; 1158 #if 0 1159 wakeup(&so->so_timeo); 1160 sorwakeup(so); 1161 sowwakeup(so); 1162 #endif 1163 } 1164 1165 static int 1166 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1167 { 1168 int error, i, n; 1169 struct inpcb *marker; 1170 struct inpcb *inp; 1171 inp_gen_t gencnt; 1172 globaldata_t gd; 1173 int origcpu, ccpu; 1174 1175 error = 0; 1176 n = 0; 1177 1178 /* 1179 * The process of preparing the TCB list is too time-consuming and 1180 * resource-intensive to repeat twice on every request. 1181 */ 1182 if (req->oldptr == NULL) { 1183 for (ccpu = 0; ccpu < ncpus; ++ccpu) { 1184 gd = globaldata_find(ccpu); 1185 n += tcbinfo[gd->gd_cpuid].ipi_count; 1186 } 1187 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb); 1188 return (0); 1189 } 1190 1191 if (req->newptr != NULL) 1192 return (EPERM); 1193 1194 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1195 marker->inp_flags |= INP_PLACEMARKER; 1196 1197 /* 1198 * OK, now we're committed to doing something. Run the inpcb list 1199 * for each cpu in the system and construct the output. Use a 1200 * list placemarker to deal with list changes occuring during 1201 * copyout blockages (but otherwise depend on being on the correct 1202 * cpu to avoid races). 1203 */ 1204 origcpu = mycpu->gd_cpuid; 1205 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) { 1206 globaldata_t rgd; 1207 caddr_t inp_ppcb; 1208 struct xtcpcb xt; 1209 int cpu_id; 1210 1211 cpu_id = (origcpu + ccpu) % ncpus; 1212 if ((smp_active_mask & (1 << cpu_id)) == 0) 1213 continue; 1214 rgd = globaldata_find(cpu_id); 1215 lwkt_setcpu_self(rgd); 1216 1217 gencnt = tcbinfo[cpu_id].ipi_gencnt; 1218 n = tcbinfo[cpu_id].ipi_count; 1219 1220 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list); 1221 i = 0; 1222 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) { 1223 /* 1224 * process a snapshot of pcbs, ignoring placemarkers 1225 * and using our own to allow SYSCTL_OUT to block. 1226 */ 1227 LIST_REMOVE(marker, inp_list); 1228 LIST_INSERT_AFTER(inp, marker, inp_list); 1229 1230 if (inp->inp_flags & INP_PLACEMARKER) 1231 continue; 1232 if (inp->inp_gencnt > gencnt) 1233 continue; 1234 if (prison_xinpcb(req->td, inp)) 1235 continue; 1236 1237 xt.xt_len = sizeof xt; 1238 bcopy(inp, &xt.xt_inp, sizeof *inp); 1239 inp_ppcb = inp->inp_ppcb; 1240 if (inp_ppcb != NULL) 1241 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1242 else 1243 bzero(&xt.xt_tp, sizeof xt.xt_tp); 1244 if (inp->inp_socket) 1245 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1246 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0) 1247 break; 1248 ++i; 1249 } 1250 LIST_REMOVE(marker, inp_list); 1251 if (error == 0 && i < n) { 1252 bzero(&xt, sizeof xt); 1253 xt.xt_len = sizeof xt; 1254 while (i < n) { 1255 error = SYSCTL_OUT(req, &xt, sizeof xt); 1256 if (error) 1257 break; 1258 ++i; 1259 } 1260 } 1261 } 1262 1263 /* 1264 * Make sure we are on the same cpu we were on originally, since 1265 * higher level callers expect this. Also don't pollute caches with 1266 * migrated userland data by (eventually) returning to userland 1267 * on a different cpu. 1268 */ 1269 lwkt_setcpu_self(globaldata_find(origcpu)); 1270 kfree(marker, M_TEMP); 1271 return (error); 1272 } 1273 1274 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1275 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1276 1277 static int 1278 tcp_getcred(SYSCTL_HANDLER_ARGS) 1279 { 1280 struct sockaddr_in addrs[2]; 1281 struct inpcb *inp; 1282 int cpu; 1283 int error; 1284 1285 error = priv_check(req->td, PRIV_ROOT); 1286 if (error != 0) 1287 return (error); 1288 error = SYSCTL_IN(req, addrs, sizeof addrs); 1289 if (error != 0) 1290 return (error); 1291 crit_enter(); 1292 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1293 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1294 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1295 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1296 if (inp == NULL || inp->inp_socket == NULL) { 1297 error = ENOENT; 1298 goto out; 1299 } 1300 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1301 out: 1302 crit_exit(); 1303 return (error); 1304 } 1305 1306 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1307 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1308 1309 #ifdef INET6 1310 static int 1311 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1312 { 1313 struct sockaddr_in6 addrs[2]; 1314 struct inpcb *inp; 1315 int error; 1316 boolean_t mapped = FALSE; 1317 1318 error = priv_check(req->td, PRIV_ROOT); 1319 if (error != 0) 1320 return (error); 1321 error = SYSCTL_IN(req, addrs, sizeof addrs); 1322 if (error != 0) 1323 return (error); 1324 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1325 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1326 mapped = TRUE; 1327 else 1328 return (EINVAL); 1329 } 1330 crit_enter(); 1331 if (mapped) { 1332 inp = in_pcblookup_hash(&tcbinfo[0], 1333 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1334 addrs[1].sin6_port, 1335 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1336 addrs[0].sin6_port, 1337 0, NULL); 1338 } else { 1339 inp = in6_pcblookup_hash(&tcbinfo[0], 1340 &addrs[1].sin6_addr, addrs[1].sin6_port, 1341 &addrs[0].sin6_addr, addrs[0].sin6_port, 1342 0, NULL); 1343 } 1344 if (inp == NULL || inp->inp_socket == NULL) { 1345 error = ENOENT; 1346 goto out; 1347 } 1348 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1349 out: 1350 crit_exit(); 1351 return (error); 1352 } 1353 1354 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1355 0, 0, 1356 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1357 #endif 1358 1359 struct netmsg_tcp_notify { 1360 struct netmsg nm_nmsg; 1361 void (*nm_notify)(struct inpcb *, int); 1362 struct in_addr nm_faddr; 1363 int nm_arg; 1364 }; 1365 1366 static void 1367 tcp_notifyall_oncpu(struct netmsg *netmsg) 1368 { 1369 struct netmsg_tcp_notify *nmsg = (struct netmsg_tcp_notify *)netmsg; 1370 int nextcpu; 1371 1372 in_pcbnotifyall(&tcbinfo[mycpuid].pcblisthead, nmsg->nm_faddr, 1373 nmsg->nm_arg, nmsg->nm_notify); 1374 1375 nextcpu = mycpuid + 1; 1376 if (nextcpu < ncpus2) 1377 lwkt_forwardmsg(tcp_cport(nextcpu), &netmsg->nm_lmsg); 1378 else 1379 lwkt_replymsg(&netmsg->nm_lmsg, 0); 1380 } 1381 1382 void 1383 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1384 { 1385 struct ip *ip = vip; 1386 struct tcphdr *th; 1387 struct in_addr faddr; 1388 struct inpcb *inp; 1389 struct tcpcb *tp; 1390 void (*notify)(struct inpcb *, int) = tcp_notify; 1391 tcp_seq icmpseq; 1392 int arg, cpu; 1393 1394 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) { 1395 return; 1396 } 1397 1398 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1399 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1400 return; 1401 1402 arg = inetctlerrmap[cmd]; 1403 if (cmd == PRC_QUENCH) { 1404 notify = tcp_quench; 1405 } else if (icmp_may_rst && 1406 (cmd == PRC_UNREACH_ADMIN_PROHIB || 1407 cmd == PRC_UNREACH_PORT || 1408 cmd == PRC_TIMXCEED_INTRANS) && 1409 ip != NULL) { 1410 notify = tcp_drop_syn_sent; 1411 } else if (cmd == PRC_MSGSIZE) { 1412 struct icmp *icmp = (struct icmp *) 1413 ((caddr_t)ip - offsetof(struct icmp, icmp_ip)); 1414 1415 arg = ntohs(icmp->icmp_nextmtu); 1416 notify = tcp_mtudisc; 1417 } else if (PRC_IS_REDIRECT(cmd)) { 1418 ip = NULL; 1419 notify = in_rtchange; 1420 } else if (cmd == PRC_HOSTDEAD) { 1421 ip = NULL; 1422 } 1423 1424 if (ip != NULL) { 1425 crit_enter(); 1426 th = (struct tcphdr *)((caddr_t)ip + 1427 (IP_VHL_HL(ip->ip_vhl) << 2)); 1428 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1429 ip->ip_src.s_addr, th->th_sport); 1430 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1431 ip->ip_src, th->th_sport, 0, NULL); 1432 if ((inp != NULL) && (inp->inp_socket != NULL)) { 1433 icmpseq = htonl(th->th_seq); 1434 tp = intotcpcb(inp); 1435 if (SEQ_GEQ(icmpseq, tp->snd_una) && 1436 SEQ_LT(icmpseq, tp->snd_max)) 1437 (*notify)(inp, arg); 1438 } else { 1439 struct in_conninfo inc; 1440 1441 inc.inc_fport = th->th_dport; 1442 inc.inc_lport = th->th_sport; 1443 inc.inc_faddr = faddr; 1444 inc.inc_laddr = ip->ip_src; 1445 #ifdef INET6 1446 inc.inc_isipv6 = 0; 1447 #endif 1448 syncache_unreach(&inc, th); 1449 } 1450 crit_exit(); 1451 } else { 1452 struct netmsg_tcp_notify nmsg; 1453 1454 KKASSERT(&curthread->td_msgport == cpu_portfn(0)); 1455 netmsg_init(&nmsg.nm_nmsg, NULL, &curthread->td_msgport, 1456 0, tcp_notifyall_oncpu); 1457 nmsg.nm_faddr = faddr; 1458 nmsg.nm_arg = arg; 1459 nmsg.nm_notify = notify; 1460 1461 lwkt_domsg(tcp_cport(0), &nmsg.nm_nmsg.nm_lmsg, 0); 1462 } 1463 } 1464 1465 #ifdef INET6 1466 void 1467 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1468 { 1469 struct tcphdr th; 1470 void (*notify) (struct inpcb *, int) = tcp_notify; 1471 struct ip6_hdr *ip6; 1472 struct mbuf *m; 1473 struct ip6ctlparam *ip6cp = NULL; 1474 const struct sockaddr_in6 *sa6_src = NULL; 1475 int off; 1476 struct tcp_portonly { 1477 u_int16_t th_sport; 1478 u_int16_t th_dport; 1479 } *thp; 1480 int arg; 1481 1482 if (sa->sa_family != AF_INET6 || 1483 sa->sa_len != sizeof(struct sockaddr_in6)) 1484 return; 1485 1486 arg = 0; 1487 if (cmd == PRC_QUENCH) 1488 notify = tcp_quench; 1489 else if (cmd == PRC_MSGSIZE) { 1490 struct ip6ctlparam *ip6cp = d; 1491 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6; 1492 1493 arg = ntohl(icmp6->icmp6_mtu); 1494 notify = tcp_mtudisc; 1495 } else if (!PRC_IS_REDIRECT(cmd) && 1496 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) { 1497 return; 1498 } 1499 1500 /* if the parameter is from icmp6, decode it. */ 1501 if (d != NULL) { 1502 ip6cp = (struct ip6ctlparam *)d; 1503 m = ip6cp->ip6c_m; 1504 ip6 = ip6cp->ip6c_ip6; 1505 off = ip6cp->ip6c_off; 1506 sa6_src = ip6cp->ip6c_src; 1507 } else { 1508 m = NULL; 1509 ip6 = NULL; 1510 off = 0; /* fool gcc */ 1511 sa6_src = &sa6_any; 1512 } 1513 1514 if (ip6 != NULL) { 1515 struct in_conninfo inc; 1516 /* 1517 * XXX: We assume that when IPV6 is non NULL, 1518 * M and OFF are valid. 1519 */ 1520 1521 /* check if we can safely examine src and dst ports */ 1522 if (m->m_pkthdr.len < off + sizeof *thp) 1523 return; 1524 1525 bzero(&th, sizeof th); 1526 m_copydata(m, off, sizeof *thp, (caddr_t)&th); 1527 1528 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport, 1529 (struct sockaddr *)ip6cp->ip6c_src, 1530 th.th_sport, cmd, arg, notify); 1531 1532 inc.inc_fport = th.th_dport; 1533 inc.inc_lport = th.th_sport; 1534 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1535 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1536 inc.inc_isipv6 = 1; 1537 syncache_unreach(&inc, &th); 1538 } else 1539 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0, 1540 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify); 1541 } 1542 #endif 1543 1544 /* 1545 * Following is where TCP initial sequence number generation occurs. 1546 * 1547 * There are two places where we must use initial sequence numbers: 1548 * 1. In SYN-ACK packets. 1549 * 2. In SYN packets. 1550 * 1551 * All ISNs for SYN-ACK packets are generated by the syncache. See 1552 * tcp_syncache.c for details. 1553 * 1554 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1555 * depends on this property. In addition, these ISNs should be 1556 * unguessable so as to prevent connection hijacking. To satisfy 1557 * the requirements of this situation, the algorithm outlined in 1558 * RFC 1948 is used to generate sequence numbers. 1559 * 1560 * Implementation details: 1561 * 1562 * Time is based off the system timer, and is corrected so that it 1563 * increases by one megabyte per second. This allows for proper 1564 * recycling on high speed LANs while still leaving over an hour 1565 * before rollover. 1566 * 1567 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1568 * between seeding of isn_secret. This is normally set to zero, 1569 * as reseeding should not be necessary. 1570 * 1571 */ 1572 1573 #define ISN_BYTES_PER_SECOND 1048576 1574 1575 u_char isn_secret[32]; 1576 int isn_last_reseed; 1577 MD5_CTX isn_ctx; 1578 1579 tcp_seq 1580 tcp_new_isn(struct tcpcb *tp) 1581 { 1582 u_int32_t md5_buffer[4]; 1583 tcp_seq new_isn; 1584 1585 /* Seed if this is the first use, reseed if requested. */ 1586 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1587 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1588 < (u_int)ticks))) { 1589 read_random_unlimited(&isn_secret, sizeof isn_secret); 1590 isn_last_reseed = ticks; 1591 } 1592 1593 /* Compute the md5 hash and return the ISN. */ 1594 MD5Init(&isn_ctx); 1595 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 1596 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 1597 #ifdef INET6 1598 if (tp->t_inpcb->inp_vflag & INP_IPV6) { 1599 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1600 sizeof(struct in6_addr)); 1601 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1602 sizeof(struct in6_addr)); 1603 } else 1604 #endif 1605 { 1606 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1607 sizeof(struct in_addr)); 1608 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1609 sizeof(struct in_addr)); 1610 } 1611 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1612 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1613 new_isn = (tcp_seq) md5_buffer[0]; 1614 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1615 return (new_isn); 1616 } 1617 1618 /* 1619 * When a source quench is received, close congestion window 1620 * to one segment. We will gradually open it again as we proceed. 1621 */ 1622 void 1623 tcp_quench(struct inpcb *inp, int error) 1624 { 1625 struct tcpcb *tp = intotcpcb(inp); 1626 1627 if (tp != NULL) { 1628 tp->snd_cwnd = tp->t_maxseg; 1629 tp->snd_wacked = 0; 1630 } 1631 } 1632 1633 /* 1634 * When a specific ICMP unreachable message is received and the 1635 * connection state is SYN-SENT, drop the connection. This behavior 1636 * is controlled by the icmp_may_rst sysctl. 1637 */ 1638 void 1639 tcp_drop_syn_sent(struct inpcb *inp, int error) 1640 { 1641 struct tcpcb *tp = intotcpcb(inp); 1642 1643 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT)) 1644 tcp_drop(tp, error); 1645 } 1646 1647 /* 1648 * When a `need fragmentation' ICMP is received, update our idea of the MSS 1649 * based on the new value in the route. Also nudge TCP to send something, 1650 * since we know the packet we just sent was dropped. 1651 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1652 */ 1653 void 1654 tcp_mtudisc(struct inpcb *inp, int mtu) 1655 { 1656 struct tcpcb *tp = intotcpcb(inp); 1657 struct rtentry *rt; 1658 struct socket *so = inp->inp_socket; 1659 int maxopd, mss; 1660 #ifdef INET6 1661 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0); 1662 #else 1663 const boolean_t isipv6 = FALSE; 1664 #endif 1665 1666 if (tp == NULL) 1667 return; 1668 1669 /* 1670 * If no MTU is provided in the ICMP message, use the 1671 * next lower likely value, as specified in RFC 1191. 1672 */ 1673 if (mtu == 0) { 1674 int oldmtu; 1675 1676 oldmtu = tp->t_maxopd + 1677 (isipv6 ? 1678 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1679 sizeof(struct tcpiphdr)); 1680 mtu = ip_next_mtu(oldmtu, 0); 1681 } 1682 1683 if (isipv6) 1684 rt = tcp_rtlookup6(&inp->inp_inc); 1685 else 1686 rt = tcp_rtlookup(&inp->inp_inc); 1687 if (rt != NULL) { 1688 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu) 1689 mtu = rt->rt_rmx.rmx_mtu; 1690 1691 maxopd = mtu - 1692 (isipv6 ? 1693 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1694 sizeof(struct tcpiphdr)); 1695 1696 /* 1697 * XXX - The following conditional probably violates the TCP 1698 * spec. The problem is that, since we don't know the 1699 * other end's MSS, we are supposed to use a conservative 1700 * default. But, if we do that, then MTU discovery will 1701 * never actually take place, because the conservative 1702 * default is much less than the MTUs typically seen 1703 * on the Internet today. For the moment, we'll sweep 1704 * this under the carpet. 1705 * 1706 * The conservative default might not actually be a problem 1707 * if the only case this occurs is when sending an initial 1708 * SYN with options and data to a host we've never talked 1709 * to before. Then, they will reply with an MSS value which 1710 * will get recorded and the new parameters should get 1711 * recomputed. For Further Study. 1712 */ 1713 if (rt->rt_rmx.rmx_mssopt && rt->rt_rmx.rmx_mssopt < maxopd) 1714 maxopd = rt->rt_rmx.rmx_mssopt; 1715 } else 1716 maxopd = mtu - 1717 (isipv6 ? 1718 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1719 sizeof(struct tcpiphdr)); 1720 1721 if (tp->t_maxopd <= maxopd) 1722 return; 1723 tp->t_maxopd = maxopd; 1724 1725 mss = maxopd; 1726 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) == 1727 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1728 mss -= TCPOLEN_TSTAMP_APPA; 1729 1730 /* round down to multiple of MCLBYTES */ 1731 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */ 1732 if (mss > MCLBYTES) 1733 mss &= ~(MCLBYTES - 1); 1734 #else 1735 if (mss > MCLBYTES) 1736 mss = (mss / MCLBYTES) * MCLBYTES; 1737 #endif 1738 1739 if (so->so_snd.ssb_hiwat < mss) 1740 mss = so->so_snd.ssb_hiwat; 1741 1742 tp->t_maxseg = mss; 1743 tp->t_rtttime = 0; 1744 tp->snd_nxt = tp->snd_una; 1745 tcp_output(tp); 1746 tcpstat.tcps_mturesent++; 1747 } 1748 1749 /* 1750 * Look-up the routing entry to the peer of this inpcb. If no route 1751 * is found and it cannot be allocated the return NULL. This routine 1752 * is called by TCP routines that access the rmx structure and by tcp_mss 1753 * to get the interface MTU. 1754 */ 1755 struct rtentry * 1756 tcp_rtlookup(struct in_conninfo *inc) 1757 { 1758 struct route *ro = &inc->inc_route; 1759 1760 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) { 1761 /* No route yet, so try to acquire one */ 1762 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1763 /* 1764 * unused portions of the structure MUST be zero'd 1765 * out because rtalloc() treats it as opaque data 1766 */ 1767 bzero(&ro->ro_dst, sizeof(struct sockaddr_in)); 1768 ro->ro_dst.sa_family = AF_INET; 1769 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1770 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1771 inc->inc_faddr; 1772 rtalloc(ro); 1773 } 1774 } 1775 return (ro->ro_rt); 1776 } 1777 1778 #ifdef INET6 1779 struct rtentry * 1780 tcp_rtlookup6(struct in_conninfo *inc) 1781 { 1782 struct route_in6 *ro6 = &inc->inc6_route; 1783 1784 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) { 1785 /* No route yet, so try to acquire one */ 1786 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1787 /* 1788 * unused portions of the structure MUST be zero'd 1789 * out because rtalloc() treats it as opaque data 1790 */ 1791 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6)); 1792 ro6->ro_dst.sin6_family = AF_INET6; 1793 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1794 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1795 rtalloc((struct route *)ro6); 1796 } 1797 } 1798 return (ro6->ro_rt); 1799 } 1800 #endif 1801 1802 #ifdef IPSEC 1803 /* compute ESP/AH header size for TCP, including outer IP header. */ 1804 size_t 1805 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1806 { 1807 struct inpcb *inp; 1808 struct mbuf *m; 1809 size_t hdrsiz; 1810 struct ip *ip; 1811 struct tcphdr *th; 1812 1813 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1814 return (0); 1815 MGETHDR(m, MB_DONTWAIT, MT_DATA); 1816 if (!m) 1817 return (0); 1818 1819 #ifdef INET6 1820 if (inp->inp_vflag & INP_IPV6) { 1821 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 1822 1823 th = (struct tcphdr *)(ip6 + 1); 1824 m->m_pkthdr.len = m->m_len = 1825 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1826 tcp_fillheaders(tp, ip6, th); 1827 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1828 } else 1829 #endif 1830 { 1831 ip = mtod(m, struct ip *); 1832 th = (struct tcphdr *)(ip + 1); 1833 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1834 tcp_fillheaders(tp, ip, th); 1835 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1836 } 1837 1838 m_free(m); 1839 return (hdrsiz); 1840 } 1841 #endif 1842 1843 /* 1844 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1845 * 1846 * This code attempts to calculate the bandwidth-delay product as a 1847 * means of determining the optimal window size to maximize bandwidth, 1848 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1849 * routers. This code also does a fairly good job keeping RTTs in check 1850 * across slow links like modems. We implement an algorithm which is very 1851 * similar (but not meant to be) TCP/Vegas. The code operates on the 1852 * transmitter side of a TCP connection and so only effects the transmit 1853 * side of the connection. 1854 * 1855 * BACKGROUND: TCP makes no provision for the management of buffer space 1856 * at the end points or at the intermediate routers and switches. A TCP 1857 * stream, whether using NewReno or not, will eventually buffer as 1858 * many packets as it is able and the only reason this typically works is 1859 * due to the fairly small default buffers made available for a connection 1860 * (typicaly 16K or 32K). As machines use larger windows and/or window 1861 * scaling it is now fairly easy for even a single TCP connection to blow-out 1862 * all available buffer space not only on the local interface, but on 1863 * intermediate routers and switches as well. NewReno makes a misguided 1864 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1865 * then backing off, then steadily increasing the window again until another 1866 * failure occurs, ad-infinitum. This results in terrible oscillation that 1867 * is only made worse as network loads increase and the idea of intentionally 1868 * blowing out network buffers is, frankly, a terrible way to manage network 1869 * resources. 1870 * 1871 * It is far better to limit the transmit window prior to the failure 1872 * condition being achieved. There are two general ways to do this: First 1873 * you can 'scan' through different transmit window sizes and locate the 1874 * point where the RTT stops increasing, indicating that you have filled the 1875 * pipe, then scan backwards until you note that RTT stops decreasing, then 1876 * repeat ad-infinitum. This method works in principle but has severe 1877 * implementation issues due to RTT variances, timer granularity, and 1878 * instability in the algorithm which can lead to many false positives and 1879 * create oscillations as well as interact badly with other TCP streams 1880 * implementing the same algorithm. 1881 * 1882 * The second method is to limit the window to the bandwidth delay product 1883 * of the link. This is the method we implement. RTT variances and our 1884 * own manipulation of the congestion window, bwnd, can potentially 1885 * destabilize the algorithm. For this reason we have to stabilize the 1886 * elements used to calculate the window. We do this by using the minimum 1887 * observed RTT, the long term average of the observed bandwidth, and 1888 * by adding two segments worth of slop. It isn't perfect but it is able 1889 * to react to changing conditions and gives us a very stable basis on 1890 * which to extend the algorithm. 1891 */ 1892 void 1893 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1894 { 1895 u_long bw; 1896 u_long bwnd; 1897 int save_ticks; 1898 int delta_ticks; 1899 1900 /* 1901 * If inflight_enable is disabled in the middle of a tcp connection, 1902 * make sure snd_bwnd is effectively disabled. 1903 */ 1904 if (!tcp_inflight_enable) { 1905 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1906 tp->snd_bandwidth = 0; 1907 return; 1908 } 1909 1910 /* 1911 * Validate the delta time. If a connection is new or has been idle 1912 * a long time we have to reset the bandwidth calculator. 1913 */ 1914 save_ticks = ticks; 1915 delta_ticks = save_ticks - tp->t_bw_rtttime; 1916 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) { 1917 tp->t_bw_rtttime = ticks; 1918 tp->t_bw_rtseq = ack_seq; 1919 if (tp->snd_bandwidth == 0) 1920 tp->snd_bandwidth = tcp_inflight_min; 1921 return; 1922 } 1923 if (delta_ticks == 0) 1924 return; 1925 1926 /* 1927 * Sanity check, plus ignore pure window update acks. 1928 */ 1929 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0) 1930 return; 1931 1932 /* 1933 * Figure out the bandwidth. Due to the tick granularity this 1934 * is a very rough number and it MUST be averaged over a fairly 1935 * long period of time. XXX we need to take into account a link 1936 * that is not using all available bandwidth, but for now our 1937 * slop will ramp us up if this case occurs and the bandwidth later 1938 * increases. 1939 */ 1940 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks; 1941 tp->t_bw_rtttime = save_ticks; 1942 tp->t_bw_rtseq = ack_seq; 1943 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1944 1945 tp->snd_bandwidth = bw; 1946 1947 /* 1948 * Calculate the semi-static bandwidth delay product, plus two maximal 1949 * segments. The additional slop puts us squarely in the sweet 1950 * spot and also handles the bandwidth run-up case. Without the 1951 * slop we could be locking ourselves into a lower bandwidth. 1952 * 1953 * Situations Handled: 1954 * (1) Prevents over-queueing of packets on LANs, especially on 1955 * high speed LANs, allowing larger TCP buffers to be 1956 * specified, and also does a good job preventing 1957 * over-queueing of packets over choke points like modems 1958 * (at least for the transmit side). 1959 * 1960 * (2) Is able to handle changing network loads (bandwidth 1961 * drops so bwnd drops, bandwidth increases so bwnd 1962 * increases). 1963 * 1964 * (3) Theoretically should stabilize in the face of multiple 1965 * connections implementing the same algorithm (this may need 1966 * a little work). 1967 * 1968 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1969 * be adjusted with a sysctl but typically only needs to be on 1970 * very slow connections. A value no smaller then 5 should 1971 * be used, but only reduce this default if you have no other 1972 * choice. 1973 */ 1974 1975 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1976 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + 1977 tcp_inflight_stab * (int)tp->t_maxseg / 10; 1978 #undef USERTT 1979 1980 if (tcp_inflight_debug > 0) { 1981 static int ltime; 1982 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 1983 ltime = ticks; 1984 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 1985 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd); 1986 } 1987 } 1988 if ((long)bwnd < tcp_inflight_min) 1989 bwnd = tcp_inflight_min; 1990 if (bwnd > tcp_inflight_max) 1991 bwnd = tcp_inflight_max; 1992 if ((long)bwnd < tp->t_maxseg * 2) 1993 bwnd = tp->t_maxseg * 2; 1994 tp->snd_bwnd = bwnd; 1995 } 1996 1997 #ifdef TCP_SIGNATURE 1998 /* 1999 * Compute TCP-MD5 hash of a TCP segment. (RFC2385) 2000 * 2001 * We do this over ip, tcphdr, segment data, and the key in the SADB. 2002 * When called from tcp_input(), we can be sure that th_sum has been 2003 * zeroed out and verified already. 2004 * 2005 * Return 0 if successful, otherwise return -1. 2006 * 2007 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a 2008 * search with the destination IP address, and a 'magic SPI' to be 2009 * determined by the application. This is hardcoded elsewhere to 1179 2010 * right now. Another branch of this code exists which uses the SPD to 2011 * specify per-application flows but it is unstable. 2012 */ 2013 int 2014 tcpsignature_compute( 2015 struct mbuf *m, /* mbuf chain */ 2016 int len, /* length of TCP data */ 2017 int optlen, /* length of TCP options */ 2018 u_char *buf, /* storage for MD5 digest */ 2019 u_int direction) /* direction of flow */ 2020 { 2021 struct ippseudo ippseudo; 2022 MD5_CTX ctx; 2023 int doff; 2024 struct ip *ip; 2025 struct ipovly *ipovly; 2026 struct secasvar *sav; 2027 struct tcphdr *th; 2028 #ifdef INET6 2029 struct ip6_hdr *ip6; 2030 struct in6_addr in6; 2031 uint32_t plen; 2032 uint16_t nhdr; 2033 #endif /* INET6 */ 2034 u_short savecsum; 2035 2036 KASSERT(m != NULL, ("passed NULL mbuf. Game over.")); 2037 KASSERT(buf != NULL, ("passed NULL storage pointer for MD5 signature")); 2038 /* 2039 * Extract the destination from the IP header in the mbuf. 2040 */ 2041 ip = mtod(m, struct ip *); 2042 #ifdef INET6 2043 ip6 = NULL; /* Make the compiler happy. */ 2044 #endif /* INET6 */ 2045 /* 2046 * Look up an SADB entry which matches the address found in 2047 * the segment. 2048 */ 2049 switch (IP_VHL_V(ip->ip_vhl)) { 2050 case IPVERSION: 2051 sav = key_allocsa(AF_INET, (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst, 2052 IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2053 break; 2054 #ifdef INET6 2055 case (IPV6_VERSION >> 4): 2056 ip6 = mtod(m, struct ip6_hdr *); 2057 sav = key_allocsa(AF_INET6, (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst, 2058 IPPROTO_TCP, htonl(TCP_SIG_SPI)); 2059 break; 2060 #endif /* INET6 */ 2061 default: 2062 return (EINVAL); 2063 /* NOTREACHED */ 2064 break; 2065 } 2066 if (sav == NULL) { 2067 kprintf("%s: SADB lookup failed\n", __func__); 2068 return (EINVAL); 2069 } 2070 MD5Init(&ctx); 2071 2072 /* 2073 * Step 1: Update MD5 hash with IP pseudo-header. 2074 * 2075 * XXX The ippseudo header MUST be digested in network byte order, 2076 * or else we'll fail the regression test. Assume all fields we've 2077 * been doing arithmetic on have been in host byte order. 2078 * XXX One cannot depend on ipovly->ih_len here. When called from 2079 * tcp_output(), the underlying ip_len member has not yet been set. 2080 */ 2081 switch (IP_VHL_V(ip->ip_vhl)) { 2082 case IPVERSION: 2083 ipovly = (struct ipovly *)ip; 2084 ippseudo.ippseudo_src = ipovly->ih_src; 2085 ippseudo.ippseudo_dst = ipovly->ih_dst; 2086 ippseudo.ippseudo_pad = 0; 2087 ippseudo.ippseudo_p = IPPROTO_TCP; 2088 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) + optlen); 2089 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo)); 2090 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip)); 2091 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen; 2092 break; 2093 #ifdef INET6 2094 /* 2095 * RFC 2385, 2.0 Proposal 2096 * For IPv6, the pseudo-header is as described in RFC 2460, namely the 2097 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero- 2098 * extended next header value (to form 32 bits), and 32-bit segment 2099 * length. 2100 * Note: Upper-Layer Packet Length comes before Next Header. 2101 */ 2102 case (IPV6_VERSION >> 4): 2103 in6 = ip6->ip6_src; 2104 in6_clearscope(&in6); 2105 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2106 in6 = ip6->ip6_dst; 2107 in6_clearscope(&in6); 2108 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr)); 2109 plen = htonl(len + sizeof(struct tcphdr) + optlen); 2110 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t)); 2111 nhdr = 0; 2112 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2113 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2114 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2115 nhdr = IPPROTO_TCP; 2116 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t)); 2117 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr)); 2118 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen; 2119 break; 2120 #endif /* INET6 */ 2121 default: 2122 return (EINVAL); 2123 /* NOTREACHED */ 2124 break; 2125 } 2126 /* 2127 * Step 2: Update MD5 hash with TCP header, excluding options. 2128 * The TCP checksum must be set to zero. 2129 */ 2130 savecsum = th->th_sum; 2131 th->th_sum = 0; 2132 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr)); 2133 th->th_sum = savecsum; 2134 /* 2135 * Step 3: Update MD5 hash with TCP segment data. 2136 * Use m_apply() to avoid an early m_pullup(). 2137 */ 2138 if (len > 0) 2139 m_apply(m, doff, len, tcpsignature_apply, &ctx); 2140 /* 2141 * Step 4: Update MD5 hash with shared secret. 2142 */ 2143 MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); 2144 MD5Final(buf, &ctx); 2145 key_sa_recordxfer(sav, m); 2146 key_freesav(sav); 2147 return (0); 2148 } 2149 2150 int 2151 tcpsignature_apply(void *fstate, void *data, unsigned int len) 2152 { 2153 2154 MD5Update((MD5_CTX *)fstate, (unsigned char *)data, len); 2155 return (0); 2156 } 2157 #endif /* TCP_SIGNATURE */ 2158