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_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 #ifdef INET6 131 #include <netinet6/ipsec6.h> 132 #endif 133 #endif 134 135 #ifdef FAST_IPSEC 136 #include <netproto/ipsec/ipsec.h> 137 #ifdef INET6 138 #include <netproto/ipsec/ipsec6.h> 139 #endif 140 #define IPSEC 141 #endif 142 143 #include <sys/md5.h> 144 #include <sys/msgport2.h> 145 #include <machine/smp.h> 146 147 #include <net/netmsg2.h> 148 149 #if !defined(KTR_TCP) 150 #define KTR_TCP KTR_ALL 151 #endif 152 KTR_INFO_MASTER(tcp); 153 KTR_INFO(KTR_TCP, tcp, rxmsg, 0, "tcp getmsg", 0); 154 KTR_INFO(KTR_TCP, tcp, wait, 1, "tcp waitmsg", 0); 155 KTR_INFO(KTR_TCP, tcp, delayed, 2, "tcp execute delayed ops", 0); 156 #define logtcp(name) KTR_LOG(tcp_ ## name) 157 158 struct inpcbinfo tcbinfo[MAXCPU]; 159 struct tcpcbackqhead tcpcbackq[MAXCPU]; 160 161 int tcp_mpsafe_proto = 0; 162 TUNABLE_INT("net.inet.tcp.mpsafe_proto", &tcp_mpsafe_proto); 163 164 static int tcp_mpsafe_thread = 0; 165 TUNABLE_INT("net.inet.tcp.mpsafe_thread", &tcp_mpsafe_thread); 166 SYSCTL_INT(_net_inet_tcp, OID_AUTO, mpsafe_thread, CTLFLAG_RW, 167 &tcp_mpsafe_thread, 0, 168 "0:BGL, 1:Adaptive BGL, 2:No BGL(experimental)"); 169 170 int tcp_mssdflt = TCP_MSS; 171 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 172 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size"); 173 174 #ifdef INET6 175 int tcp_v6mssdflt = TCP6_MSS; 176 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW, 177 &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6"); 178 #endif 179 180 #if 0 181 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 182 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 183 &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time"); 184 #endif 185 186 int tcp_do_rfc1323 = 1; 187 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 188 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions"); 189 190 int tcp_do_rfc1644 = 0; 191 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 192 &tcp_do_rfc1644, 0, "Enable rfc1644 (TTCP) extensions"); 193 194 static int tcp_tcbhashsize = 0; 195 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 196 &tcp_tcbhashsize, 0, "Size of TCP control block hashtable"); 197 198 static int do_tcpdrain = 1; 199 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0, 200 "Enable tcp_drain routine for extra help when low on mbufs"); 201 202 /* XXX JH */ 203 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 204 &tcbinfo[0].ipi_count, 0, "Number of active PCBs"); 205 206 static int icmp_may_rst = 1; 207 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 208 "Certain ICMP unreachable messages may abort connections in SYN_SENT"); 209 210 static int tcp_isn_reseed_interval = 0; 211 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, 212 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); 213 214 /* 215 * TCP bandwidth limiting sysctls. Note that the default lower bound of 216 * 1024 exists only for debugging. A good production default would be 217 * something like 6100. 218 */ 219 static int tcp_inflight_enable = 0; 220 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW, 221 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting"); 222 223 static int tcp_inflight_debug = 0; 224 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW, 225 &tcp_inflight_debug, 0, "Debug TCP inflight calculations"); 226 227 static int tcp_inflight_min = 6144; 228 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW, 229 &tcp_inflight_min, 0, "Lower bound for TCP inflight window"); 230 231 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT; 232 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW, 233 &tcp_inflight_max, 0, "Upper bound for TCP inflight window"); 234 235 static int tcp_inflight_stab = 20; 236 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW, 237 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 2 packets)"); 238 239 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives"); 240 static struct malloc_pipe tcptemp_mpipe; 241 242 static void tcp_willblock(int); 243 static void tcp_cleartaocache (void); 244 static void tcp_notify (struct inpcb *, int); 245 246 struct tcp_stats tcpstats_percpu[MAXCPU]; 247 #ifdef SMP 248 static int 249 sysctl_tcpstats(SYSCTL_HANDLER_ARGS) 250 { 251 int cpu, error = 0; 252 253 for (cpu = 0; cpu < ncpus; ++cpu) { 254 if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu], 255 sizeof(struct tcp_stats)))) 256 break; 257 if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu], 258 sizeof(struct tcp_stats)))) 259 break; 260 } 261 262 return (error); 263 } 264 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 265 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics"); 266 #else 267 SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW, 268 &tcpstat, tcp_stats, "TCP statistics"); 269 #endif 270 271 /* 272 * Target size of TCP PCB hash tables. Must be a power of two. 273 * 274 * Note that this can be overridden by the kernel environment 275 * variable net.inet.tcp.tcbhashsize 276 */ 277 #ifndef TCBHASHSIZE 278 #define TCBHASHSIZE 512 279 #endif 280 281 /* 282 * This is the actual shape of what we allocate using the zone 283 * allocator. Doing it this way allows us to protect both structures 284 * using the same generation count, and also eliminates the overhead 285 * of allocating tcpcbs separately. By hiding the structure here, 286 * we avoid changing most of the rest of the code (although it needs 287 * to be changed, eventually, for greater efficiency). 288 */ 289 #define ALIGNMENT 32 290 #define ALIGNM1 (ALIGNMENT - 1) 291 struct inp_tp { 292 union { 293 struct inpcb inp; 294 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 295 } inp_tp_u; 296 struct tcpcb tcb; 297 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl; 298 struct callout inp_tp_delack; 299 struct netmsg_tcp_timer inp_tp_timermsg; 300 }; 301 #undef ALIGNMENT 302 #undef ALIGNM1 303 304 /* 305 * Tcp initialization 306 */ 307 void 308 tcp_init(void) 309 { 310 struct inpcbporthead *porthashbase; 311 u_long porthashmask; 312 struct vm_zone *ipi_zone; 313 int hashsize = TCBHASHSIZE; 314 int cpu; 315 316 /* 317 * note: tcptemp is used for keepalives, and it is ok for an 318 * allocation to fail so do not specify MPF_INT. 319 */ 320 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp), 321 25, -1, 0, NULL); 322 323 tcp_ccgen = 1; 324 tcp_cleartaocache(); 325 326 tcp_delacktime = TCPTV_DELACK; 327 tcp_keepinit = TCPTV_KEEP_INIT; 328 tcp_keepidle = TCPTV_KEEP_IDLE; 329 tcp_keepintvl = TCPTV_KEEPINTVL; 330 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 331 tcp_msl = TCPTV_MSL; 332 tcp_rexmit_min = TCPTV_MIN; 333 tcp_rexmit_slop = TCPTV_CPU_VAR; 334 335 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 336 if (!powerof2(hashsize)) { 337 kprintf("WARNING: TCB hash size not a power of 2\n"); 338 hashsize = 512; /* safe default */ 339 } 340 tcp_tcbhashsize = hashsize; 341 porthashbase = hashinit(hashsize, M_PCB, &porthashmask); 342 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 343 ZONE_INTERRUPT, 0); 344 345 for (cpu = 0; cpu < ncpus2; cpu++) { 346 in_pcbinfo_init(&tcbinfo[cpu]); 347 tcbinfo[cpu].cpu = cpu; 348 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB, 349 &tcbinfo[cpu].hashmask); 350 tcbinfo[cpu].porthashbase = porthashbase; 351 tcbinfo[cpu].porthashmask = porthashmask; 352 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB, 353 &tcbinfo[cpu].wildcardhashmask); 354 tcbinfo[cpu].ipi_zone = ipi_zone; 355 TAILQ_INIT(&tcpcbackq[cpu]); 356 } 357 358 tcp_reass_maxseg = nmbclusters / 16; 359 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg); 360 361 #ifdef INET6 362 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 363 #else 364 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 365 #endif 366 if (max_protohdr < TCP_MINPROTOHDR) 367 max_protohdr = TCP_MINPROTOHDR; 368 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 369 panic("tcp_init"); 370 #undef TCP_MINPROTOHDR 371 372 /* 373 * Initialize TCP statistics counters for each CPU. 374 */ 375 #ifdef SMP 376 for (cpu = 0; cpu < ncpus; ++cpu) { 377 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats)); 378 } 379 #else 380 bzero(&tcpstat, sizeof(struct tcp_stats)); 381 #endif 382 383 syncache_init(); 384 tcp_thread_init(); 385 } 386 387 void 388 tcpmsg_service_loop(void *dummy) 389 { 390 struct netmsg *msg; 391 int mplocked; 392 393 /* 394 * Thread was started with TDF_MPSAFE 395 */ 396 mplocked = 0; 397 398 while ((msg = lwkt_waitport(&curthread->td_msgport, 0))) { 399 do { 400 logtcp(rxmsg); 401 mplocked = netmsg_service(msg, tcp_mpsafe_thread, 402 mplocked); 403 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL); 404 405 logtcp(delayed); 406 tcp_willblock(mplocked); 407 logtcp(wait); 408 } 409 } 410 411 static void 412 tcp_willblock(int mplocked) 413 { 414 struct tcpcb *tp; 415 int cpu = mycpu->gd_cpuid; 416 int unlock = 0; 417 418 if (!mplocked && !tcp_mpsafe_proto) { 419 if (TAILQ_EMPTY(&tcpcbackq[cpu])) 420 return; 421 422 get_mplock(); 423 mplocked = 1; 424 unlock = 1; 425 } 426 427 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) { 428 KKASSERT(tp->t_flags & TF_ONOUTPUTQ); 429 tp->t_flags &= ~TF_ONOUTPUTQ; 430 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq); 431 tcp_output(tp); 432 } 433 434 if (unlock) 435 rel_mplock(); 436 } 437 438 439 /* 440 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 441 * tcp_template used to store this data in mbufs, but we now recopy it out 442 * of the tcpcb each time to conserve mbufs. 443 */ 444 void 445 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr) 446 { 447 struct inpcb *inp = tp->t_inpcb; 448 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 449 450 #ifdef INET6 451 if (inp->inp_vflag & INP_IPV6) { 452 struct ip6_hdr *ip6; 453 454 ip6 = (struct ip6_hdr *)ip_ptr; 455 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 456 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 457 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 458 (IPV6_VERSION & IPV6_VERSION_MASK); 459 ip6->ip6_nxt = IPPROTO_TCP; 460 ip6->ip6_plen = sizeof(struct tcphdr); 461 ip6->ip6_src = inp->in6p_laddr; 462 ip6->ip6_dst = inp->in6p_faddr; 463 tcp_hdr->th_sum = 0; 464 } else 465 #endif 466 { 467 struct ip *ip = (struct ip *) ip_ptr; 468 469 ip->ip_vhl = IP_VHL_BORING; 470 ip->ip_tos = 0; 471 ip->ip_len = 0; 472 ip->ip_id = 0; 473 ip->ip_off = 0; 474 ip->ip_ttl = 0; 475 ip->ip_sum = 0; 476 ip->ip_p = IPPROTO_TCP; 477 ip->ip_src = inp->inp_laddr; 478 ip->ip_dst = inp->inp_faddr; 479 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, 480 ip->ip_dst.s_addr, 481 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 482 } 483 484 tcp_hdr->th_sport = inp->inp_lport; 485 tcp_hdr->th_dport = inp->inp_fport; 486 tcp_hdr->th_seq = 0; 487 tcp_hdr->th_ack = 0; 488 tcp_hdr->th_x2 = 0; 489 tcp_hdr->th_off = 5; 490 tcp_hdr->th_flags = 0; 491 tcp_hdr->th_win = 0; 492 tcp_hdr->th_urp = 0; 493 } 494 495 /* 496 * Create template to be used to send tcp packets on a connection. 497 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 498 * use for this function is in keepalives, which use tcp_respond. 499 */ 500 struct tcptemp * 501 tcp_maketemplate(struct tcpcb *tp) 502 { 503 struct tcptemp *tmp; 504 505 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL) 506 return (NULL); 507 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t); 508 return (tmp); 509 } 510 511 void 512 tcp_freetemplate(struct tcptemp *tmp) 513 { 514 mpipe_free(&tcptemp_mpipe, tmp); 515 } 516 517 /* 518 * Send a single message to the TCP at address specified by 519 * the given TCP/IP header. If m == NULL, then we make a copy 520 * of the tcpiphdr at ti and send directly to the addressed host. 521 * This is used to force keep alive messages out using the TCP 522 * template for a connection. If flags are given then we send 523 * a message back to the TCP which originated the * segment ti, 524 * and discard the mbuf containing it and any other attached mbufs. 525 * 526 * In any case the ack and sequence number of the transmitted 527 * segment are as specified by the parameters. 528 * 529 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 530 */ 531 void 532 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 533 tcp_seq ack, tcp_seq seq, int flags) 534 { 535 int tlen; 536 int win = 0; 537 struct route *ro = NULL; 538 struct route sro; 539 struct ip *ip = ipgen; 540 struct tcphdr *nth; 541 int ipflags = 0; 542 struct route_in6 *ro6 = NULL; 543 struct route_in6 sro6; 544 struct ip6_hdr *ip6 = ipgen; 545 boolean_t use_tmpro = TRUE; 546 #ifdef INET6 547 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6); 548 #else 549 const boolean_t isipv6 = FALSE; 550 #endif 551 552 if (tp != NULL) { 553 if (!(flags & TH_RST)) { 554 win = ssb_space(&tp->t_inpcb->inp_socket->so_rcv); 555 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 556 win = (long)TCP_MAXWIN << tp->rcv_scale; 557 } 558 /* 559 * Don't use the route cache of a listen socket, 560 * it is not MPSAFE; use temporary route cache. 561 */ 562 if (tp->t_state != TCPS_LISTEN) { 563 if (isipv6) 564 ro6 = &tp->t_inpcb->in6p_route; 565 else 566 ro = &tp->t_inpcb->inp_route; 567 use_tmpro = FALSE; 568 } 569 } 570 if (use_tmpro) { 571 if (isipv6) { 572 ro6 = &sro6; 573 bzero(ro6, sizeof *ro6); 574 } else { 575 ro = &sro; 576 bzero(ro, sizeof *ro); 577 } 578 } 579 if (m == NULL) { 580 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 581 if (m == NULL) 582 return; 583 tlen = 0; 584 m->m_data += max_linkhdr; 585 if (isipv6) { 586 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr)); 587 ip6 = mtod(m, struct ip6_hdr *); 588 nth = (struct tcphdr *)(ip6 + 1); 589 } else { 590 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); 591 ip = mtod(m, struct ip *); 592 nth = (struct tcphdr *)(ip + 1); 593 } 594 bcopy(th, nth, sizeof(struct tcphdr)); 595 flags = TH_ACK; 596 } else { 597 m_freem(m->m_next); 598 m->m_next = NULL; 599 m->m_data = (caddr_t)ipgen; 600 /* m_len is set later */ 601 tlen = 0; 602 #define xchg(a, b, type) { type t; t = a; a = b; b = t; } 603 if (isipv6) { 604 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 605 nth = (struct tcphdr *)(ip6 + 1); 606 } else { 607 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 608 nth = (struct tcphdr *)(ip + 1); 609 } 610 if (th != nth) { 611 /* 612 * this is usually a case when an extension header 613 * exists between the IPv6 header and the 614 * TCP header. 615 */ 616 nth->th_sport = th->th_sport; 617 nth->th_dport = th->th_dport; 618 } 619 xchg(nth->th_dport, nth->th_sport, n_short); 620 #undef xchg 621 } 622 if (isipv6) { 623 ip6->ip6_flow = 0; 624 ip6->ip6_vfc = IPV6_VERSION; 625 ip6->ip6_nxt = IPPROTO_TCP; 626 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen)); 627 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 628 } else { 629 tlen += sizeof(struct tcpiphdr); 630 ip->ip_len = tlen; 631 ip->ip_ttl = ip_defttl; 632 } 633 m->m_len = tlen; 634 m->m_pkthdr.len = tlen; 635 m->m_pkthdr.rcvif = (struct ifnet *) NULL; 636 nth->th_seq = htonl(seq); 637 nth->th_ack = htonl(ack); 638 nth->th_x2 = 0; 639 nth->th_off = sizeof(struct tcphdr) >> 2; 640 nth->th_flags = flags; 641 if (tp != NULL) 642 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 643 else 644 nth->th_win = htons((u_short)win); 645 nth->th_urp = 0; 646 if (isipv6) { 647 nth->th_sum = 0; 648 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 649 sizeof(struct ip6_hdr), 650 tlen - sizeof(struct ip6_hdr)); 651 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 652 (ro6 && ro6->ro_rt) ? 653 ro6->ro_rt->rt_ifp : NULL); 654 } else { 655 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 656 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 657 m->m_pkthdr.csum_flags = CSUM_TCP; 658 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 659 } 660 #ifdef TCPDEBUG 661 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 662 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 663 #endif 664 if (isipv6) { 665 ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 666 tp ? tp->t_inpcb : NULL); 667 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) { 668 RTFREE(ro6->ro_rt); 669 ro6->ro_rt = NULL; 670 } 671 } else { 672 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 673 if ((ro == &sro) && (ro->ro_rt != NULL)) { 674 RTFREE(ro->ro_rt); 675 ro->ro_rt = NULL; 676 } 677 } 678 } 679 680 /* 681 * Create a new TCP control block, making an 682 * empty reassembly queue and hooking it to the argument 683 * protocol control block. The `inp' parameter must have 684 * come from the zone allocator set up in tcp_init(). 685 */ 686 struct tcpcb * 687 tcp_newtcpcb(struct inpcb *inp) 688 { 689 struct inp_tp *it; 690 struct tcpcb *tp; 691 #ifdef INET6 692 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 693 #else 694 const boolean_t isipv6 = FALSE; 695 #endif 696 697 it = (struct inp_tp *)inp; 698 tp = &it->tcb; 699 bzero(tp, sizeof(struct tcpcb)); 700 LIST_INIT(&tp->t_segq); 701 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt; 702 703 /* Set up our timeouts. */ 704 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt); 705 callout_init(tp->tt_persist = &it->inp_tp_persist); 706 callout_init(tp->tt_keep = &it->inp_tp_keep); 707 callout_init(tp->tt_2msl = &it->inp_tp_2msl); 708 callout_init(tp->tt_delack = &it->inp_tp_delack); 709 710 tp->tt_msg = &it->inp_tp_timermsg; 711 if (isipv6) { 712 /* Don't mess with IPv6; always create timer message */ 713 tcp_create_timermsg(tp); 714 } else { 715 /* 716 * Zero out timer message. We don't create it here, 717 * since the current CPU may not be the owner of this 718 * inpcb. 719 */ 720 bzero(tp->tt_msg, sizeof(*tp->tt_msg)); 721 } 722 723 if (tcp_do_rfc1323) 724 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP); 725 if (tcp_do_rfc1644) 726 tp->t_flags |= TF_REQ_CC; 727 tp->t_inpcb = inp; /* XXX */ 728 tp->t_state = TCPS_CLOSED; 729 /* 730 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 731 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 732 * reasonable initial retransmit time. 733 */ 734 tp->t_srtt = TCPTV_SRTTBASE; 735 tp->t_rttvar = 736 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 737 tp->t_rttmin = tcp_rexmit_min; 738 tp->t_rxtcur = TCPTV_RTOBASE; 739 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 740 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 741 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 742 tp->t_rcvtime = ticks; 743 /* 744 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 745 * because the socket may be bound to an IPv6 wildcard address, 746 * which may match an IPv4-mapped IPv6 address. 747 */ 748 inp->inp_ip_ttl = ip_defttl; 749 inp->inp_ppcb = tp; 750 tcp_sack_tcpcb_init(tp); 751 return (tp); /* XXX */ 752 } 753 754 /* 755 * Drop a TCP connection, reporting the specified error. 756 * If connection is synchronized, then send a RST to peer. 757 */ 758 struct tcpcb * 759 tcp_drop(struct tcpcb *tp, int error) 760 { 761 struct socket *so = tp->t_inpcb->inp_socket; 762 763 if (TCPS_HAVERCVDSYN(tp->t_state)) { 764 tp->t_state = TCPS_CLOSED; 765 tcp_output(tp); 766 tcpstat.tcps_drops++; 767 } else 768 tcpstat.tcps_conndrops++; 769 if (error == ETIMEDOUT && tp->t_softerror) 770 error = tp->t_softerror; 771 so->so_error = error; 772 return (tcp_close(tp)); 773 } 774 775 #ifdef SMP 776 777 struct netmsg_remwildcard { 778 struct netmsg nm_netmsg; 779 struct inpcb *nm_inp; 780 struct inpcbinfo *nm_pcbinfo; 781 #if defined(INET6) 782 int nm_isinet6; 783 #else 784 int nm_unused01; 785 #endif 786 }; 787 788 /* 789 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the 790 * inp can be detached. We do this by cycling through the cpus, ending up 791 * on the cpu controlling the inp last and then doing the disconnect. 792 */ 793 static void 794 in_pcbremwildcardhash_handler(struct netmsg *msg0) 795 { 796 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0; 797 int cpu; 798 799 cpu = msg->nm_pcbinfo->cpu; 800 801 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) { 802 /* note: detach removes any wildcard hash entry */ 803 #ifdef INET6 804 if (msg->nm_isinet6) 805 in6_pcbdetach(msg->nm_inp); 806 else 807 #endif 808 in_pcbdetach(msg->nm_inp); 809 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0); 810 } else { 811 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo); 812 cpu = (cpu + 1) % ncpus2; 813 msg->nm_pcbinfo = &tcbinfo[cpu]; 814 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 815 } 816 } 817 818 #endif 819 820 /* 821 * Close a TCP control block: 822 * discard all space held by the tcp 823 * discard internet protocol block 824 * wake up any sleepers 825 */ 826 struct tcpcb * 827 tcp_close(struct tcpcb *tp) 828 { 829 struct tseg_qent *q; 830 struct inpcb *inp = tp->t_inpcb; 831 struct socket *so = inp->inp_socket; 832 struct rtentry *rt; 833 boolean_t dosavessthresh; 834 #ifdef SMP 835 int cpu; 836 #endif 837 #ifdef INET6 838 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 839 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0); 840 #else 841 const boolean_t isipv6 = FALSE; 842 #endif 843 844 /* 845 * The tp is not instantly destroyed in the wildcard case. Setting 846 * the state to TCPS_TERMINATING will prevent the TCP stack from 847 * messing with it, though it should be noted that this change may 848 * not take effect on other cpus until we have chained the wildcard 849 * hash removal. 850 * 851 * XXX we currently depend on the BGL to synchronize the tp->t_state 852 * update and prevent other tcp protocol threads from accepting new 853 * connections on the listen socket we might be trying to close down. 854 */ 855 KKASSERT(tp->t_state != TCPS_TERMINATING); 856 tp->t_state = TCPS_TERMINATING; 857 858 /* 859 * Make sure that all of our timers are stopped before we 860 * delete the PCB. 861 */ 862 callout_stop(tp->tt_rexmt); 863 callout_stop(tp->tt_persist); 864 callout_stop(tp->tt_keep); 865 callout_stop(tp->tt_2msl); 866 callout_stop(tp->tt_delack); 867 868 if (tp->t_flags & TF_ONOUTPUTQ) { 869 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid); 870 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq); 871 tp->t_flags &= ~TF_ONOUTPUTQ; 872 } 873 874 /* 875 * If we got enough samples through the srtt filter, 876 * save the rtt and rttvar in the routing entry. 877 * 'Enough' is arbitrarily defined as the 16 samples. 878 * 16 samples is enough for the srtt filter to converge 879 * to within 5% of the correct value; fewer samples and 880 * we could save a very bogus rtt. 881 * 882 * Don't update the default route's characteristics and don't 883 * update anything that the user "locked". 884 */ 885 if (tp->t_rttupdated >= 16) { 886 u_long i = 0; 887 888 if (isipv6) { 889 struct sockaddr_in6 *sin6; 890 891 if ((rt = inp->in6p_route.ro_rt) == NULL) 892 goto no_valid_rt; 893 sin6 = (struct sockaddr_in6 *)rt_key(rt); 894 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 895 goto no_valid_rt; 896 } else 897 if ((rt = inp->inp_route.ro_rt) == NULL || 898 ((struct sockaddr_in *)rt_key(rt))-> 899 sin_addr.s_addr == INADDR_ANY) 900 goto no_valid_rt; 901 902 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) { 903 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 904 if (rt->rt_rmx.rmx_rtt && i) 905 /* 906 * filter this update to half the old & half 907 * the new values, converting scale. 908 * See route.h and tcp_var.h for a 909 * description of the scaling constants. 910 */ 911 rt->rt_rmx.rmx_rtt = 912 (rt->rt_rmx.rmx_rtt + i) / 2; 913 else 914 rt->rt_rmx.rmx_rtt = i; 915 tcpstat.tcps_cachedrtt++; 916 } 917 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) { 918 i = tp->t_rttvar * 919 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 920 if (rt->rt_rmx.rmx_rttvar && i) 921 rt->rt_rmx.rmx_rttvar = 922 (rt->rt_rmx.rmx_rttvar + i) / 2; 923 else 924 rt->rt_rmx.rmx_rttvar = i; 925 tcpstat.tcps_cachedrttvar++; 926 } 927 /* 928 * The old comment here said: 929 * update the pipelimit (ssthresh) if it has been updated 930 * already or if a pipesize was specified & the threshhold 931 * got below half the pipesize. I.e., wait for bad news 932 * before we start updating, then update on both good 933 * and bad news. 934 * 935 * But we want to save the ssthresh even if no pipesize is 936 * specified explicitly in the route, because such 937 * connections still have an implicit pipesize specified 938 * by the global tcp_sendspace. In the absence of a reliable 939 * way to calculate the pipesize, it will have to do. 940 */ 941 i = tp->snd_ssthresh; 942 if (rt->rt_rmx.rmx_sendpipe != 0) 943 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2); 944 else 945 dosavessthresh = (i < so->so_snd.ssb_hiwat/2); 946 if (dosavessthresh || 947 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) && 948 (rt->rt_rmx.rmx_ssthresh != 0))) { 949 /* 950 * convert the limit from user data bytes to 951 * packets then to packet data bytes. 952 */ 953 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 954 if (i < 2) 955 i = 2; 956 i *= tp->t_maxseg + 957 (isipv6 ? 958 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 959 sizeof(struct tcpiphdr)); 960 if (rt->rt_rmx.rmx_ssthresh) 961 rt->rt_rmx.rmx_ssthresh = 962 (rt->rt_rmx.rmx_ssthresh + i) / 2; 963 else 964 rt->rt_rmx.rmx_ssthresh = i; 965 tcpstat.tcps_cachedssthresh++; 966 } 967 } 968 969 no_valid_rt: 970 /* free the reassembly queue, if any */ 971 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 972 LIST_REMOVE(q, tqe_q); 973 m_freem(q->tqe_m); 974 FREE(q, M_TSEGQ); 975 tcp_reass_qsize--; 976 } 977 /* throw away SACK blocks in scoreboard*/ 978 if (TCP_DO_SACK(tp)) 979 tcp_sack_cleanup(&tp->scb); 980 981 inp->inp_ppcb = NULL; 982 soisdisconnected(so); 983 984 tcp_destroy_timermsg(tp); 985 986 /* 987 * Discard the inp. In the SMP case a wildcard inp's hash (created 988 * by a listen socket or an INADDR_ANY udp socket) is replicated 989 * for each protocol thread and must be removed in the context of 990 * that thread. This is accomplished by chaining the message 991 * through the cpus. 992 * 993 * If the inp is not wildcarded we simply detach, which will remove 994 * the any hashes still present for this inp. 995 */ 996 #ifdef SMP 997 if (inp->inp_flags & INP_WILDCARD_MP) { 998 struct netmsg_remwildcard *msg; 999 1000 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2; 1001 msg = kmalloc(sizeof(struct netmsg_remwildcard), 1002 M_LWKTMSG, M_INTWAIT); 1003 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0, 1004 in_pcbremwildcardhash_handler); 1005 #ifdef INET6 1006 msg->nm_isinet6 = isafinet6; 1007 #endif 1008 msg->nm_inp = inp; 1009 msg->nm_pcbinfo = &tcbinfo[cpu]; 1010 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1011 } else 1012 #endif 1013 { 1014 /* note: detach removes any wildcard hash entry */ 1015 #ifdef INET6 1016 if (isafinet6) 1017 in6_pcbdetach(inp); 1018 else 1019 #endif 1020 in_pcbdetach(inp); 1021 } 1022 tcpstat.tcps_closed++; 1023 return (NULL); 1024 } 1025 1026 static __inline void 1027 tcp_drain_oncpu(struct inpcbhead *head) 1028 { 1029 struct inpcb *inpb; 1030 struct tcpcb *tcpb; 1031 struct tseg_qent *te; 1032 1033 LIST_FOREACH(inpb, head, inp_list) { 1034 if (inpb->inp_flags & INP_PLACEMARKER) 1035 continue; 1036 if ((tcpb = intotcpcb(inpb))) { 1037 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) { 1038 LIST_REMOVE(te, tqe_q); 1039 m_freem(te->tqe_m); 1040 FREE(te, M_TSEGQ); 1041 tcp_reass_qsize--; 1042 } 1043 } 1044 } 1045 } 1046 1047 #ifdef SMP 1048 struct netmsg_tcp_drain { 1049 struct netmsg nm_netmsg; 1050 struct inpcbhead *nm_head; 1051 }; 1052 1053 static void 1054 tcp_drain_handler(netmsg_t netmsg) 1055 { 1056 struct netmsg_tcp_drain *nm = (void *)netmsg; 1057 1058 tcp_drain_oncpu(nm->nm_head); 1059 lwkt_replymsg(&nm->nm_netmsg.nm_lmsg, 0); 1060 } 1061 #endif 1062 1063 void 1064 tcp_drain(void) 1065 { 1066 #ifdef SMP 1067 int cpu; 1068 #endif 1069 1070 if (!do_tcpdrain) 1071 return; 1072 1073 /* 1074 * Walk the tcpbs, if existing, and flush the reassembly queue, 1075 * if there is one... 1076 * XXX: The "Net/3" implementation doesn't imply that the TCP 1077 * reassembly queue should be flushed, but in a situation 1078 * where we're really low on mbufs, this is potentially 1079 * useful. 1080 */ 1081 #ifdef SMP 1082 for (cpu = 0; cpu < ncpus2; cpu++) { 1083 struct netmsg_tcp_drain *msg; 1084 1085 if (cpu == mycpu->gd_cpuid) { 1086 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead); 1087 } else { 1088 msg = kmalloc(sizeof(struct netmsg_tcp_drain), 1089 M_LWKTMSG, M_NOWAIT); 1090 if (msg == NULL) 1091 continue; 1092 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0, 1093 tcp_drain_handler); 1094 msg->nm_head = &tcbinfo[cpu].pcblisthead; 1095 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1096 } 1097 } 1098 #else 1099 tcp_drain_oncpu(&tcbinfo[0].pcblisthead); 1100 #endif 1101 } 1102 1103 /* 1104 * Notify a tcp user of an asynchronous error; 1105 * store error as soft error, but wake up user 1106 * (for now, won't do anything until can select for soft error). 1107 * 1108 * Do not wake up user since there currently is no mechanism for 1109 * reporting soft errors (yet - a kqueue filter may be added). 1110 */ 1111 static void 1112 tcp_notify(struct inpcb *inp, int error) 1113 { 1114 struct tcpcb *tp = intotcpcb(inp); 1115 1116 /* 1117 * Ignore some errors if we are hooked up. 1118 * If connection hasn't completed, has retransmitted several times, 1119 * and receives a second error, give up now. This is better 1120 * than waiting a long time to establish a connection that 1121 * can never complete. 1122 */ 1123 if (tp->t_state == TCPS_ESTABLISHED && 1124 (error == EHOSTUNREACH || error == ENETUNREACH || 1125 error == EHOSTDOWN)) { 1126 return; 1127 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1128 tp->t_softerror) 1129 tcp_drop(tp, error); 1130 else 1131 tp->t_softerror = error; 1132 #if 0 1133 wakeup(&so->so_timeo); 1134 sorwakeup(so); 1135 sowwakeup(so); 1136 #endif 1137 } 1138 1139 static int 1140 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1141 { 1142 int error, i, n; 1143 struct inpcb *marker; 1144 struct inpcb *inp; 1145 inp_gen_t gencnt; 1146 globaldata_t gd; 1147 int origcpu, ccpu; 1148 1149 error = 0; 1150 n = 0; 1151 1152 /* 1153 * The process of preparing the TCB list is too time-consuming and 1154 * resource-intensive to repeat twice on every request. 1155 */ 1156 if (req->oldptr == NULL) { 1157 for (ccpu = 0; ccpu < ncpus; ++ccpu) { 1158 gd = globaldata_find(ccpu); 1159 n += tcbinfo[gd->gd_cpuid].ipi_count; 1160 } 1161 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb); 1162 return (0); 1163 } 1164 1165 if (req->newptr != NULL) 1166 return (EPERM); 1167 1168 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1169 marker->inp_flags |= INP_PLACEMARKER; 1170 1171 /* 1172 * OK, now we're committed to doing something. Run the inpcb list 1173 * for each cpu in the system and construct the output. Use a 1174 * list placemarker to deal with list changes occuring during 1175 * copyout blockages (but otherwise depend on being on the correct 1176 * cpu to avoid races). 1177 */ 1178 origcpu = mycpu->gd_cpuid; 1179 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) { 1180 globaldata_t rgd; 1181 caddr_t inp_ppcb; 1182 struct xtcpcb xt; 1183 int cpu_id; 1184 1185 cpu_id = (origcpu + ccpu) % ncpus; 1186 if ((smp_active_mask & (1 << cpu_id)) == 0) 1187 continue; 1188 rgd = globaldata_find(cpu_id); 1189 lwkt_setcpu_self(rgd); 1190 1191 gencnt = tcbinfo[cpu_id].ipi_gencnt; 1192 n = tcbinfo[cpu_id].ipi_count; 1193 1194 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list); 1195 i = 0; 1196 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) { 1197 /* 1198 * process a snapshot of pcbs, ignoring placemarkers 1199 * and using our own to allow SYSCTL_OUT to block. 1200 */ 1201 LIST_REMOVE(marker, inp_list); 1202 LIST_INSERT_AFTER(inp, marker, inp_list); 1203 1204 if (inp->inp_flags & INP_PLACEMARKER) 1205 continue; 1206 if (inp->inp_gencnt > gencnt) 1207 continue; 1208 if (prison_xinpcb(req->td, inp)) 1209 continue; 1210 1211 xt.xt_len = sizeof xt; 1212 bcopy(inp, &xt.xt_inp, sizeof *inp); 1213 inp_ppcb = inp->inp_ppcb; 1214 if (inp_ppcb != NULL) 1215 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1216 else 1217 bzero(&xt.xt_tp, sizeof xt.xt_tp); 1218 if (inp->inp_socket) 1219 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1220 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0) 1221 break; 1222 ++i; 1223 } 1224 LIST_REMOVE(marker, inp_list); 1225 if (error == 0 && i < n) { 1226 bzero(&xt, sizeof xt); 1227 xt.xt_len = sizeof xt; 1228 while (i < n) { 1229 error = SYSCTL_OUT(req, &xt, sizeof xt); 1230 if (error) 1231 break; 1232 ++i; 1233 } 1234 } 1235 } 1236 1237 /* 1238 * Make sure we are on the same cpu we were on originally, since 1239 * higher level callers expect this. Also don't pollute caches with 1240 * migrated userland data by (eventually) returning to userland 1241 * on a different cpu. 1242 */ 1243 lwkt_setcpu_self(globaldata_find(origcpu)); 1244 kfree(marker, M_TEMP); 1245 return (error); 1246 } 1247 1248 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1249 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1250 1251 static int 1252 tcp_getcred(SYSCTL_HANDLER_ARGS) 1253 { 1254 struct sockaddr_in addrs[2]; 1255 struct inpcb *inp; 1256 int cpu; 1257 int error; 1258 1259 error = priv_check(req->td, PRIV_ROOT); 1260 if (error != 0) 1261 return (error); 1262 error = SYSCTL_IN(req, addrs, sizeof addrs); 1263 if (error != 0) 1264 return (error); 1265 crit_enter(); 1266 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1267 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1268 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1269 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1270 if (inp == NULL || inp->inp_socket == NULL) { 1271 error = ENOENT; 1272 goto out; 1273 } 1274 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1275 out: 1276 crit_exit(); 1277 return (error); 1278 } 1279 1280 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1281 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1282 1283 #ifdef INET6 1284 static int 1285 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1286 { 1287 struct sockaddr_in6 addrs[2]; 1288 struct inpcb *inp; 1289 int error; 1290 boolean_t mapped = FALSE; 1291 1292 error = priv_check(req->td, PRIV_ROOT); 1293 if (error != 0) 1294 return (error); 1295 error = SYSCTL_IN(req, addrs, sizeof addrs); 1296 if (error != 0) 1297 return (error); 1298 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1299 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1300 mapped = TRUE; 1301 else 1302 return (EINVAL); 1303 } 1304 crit_enter(); 1305 if (mapped) { 1306 inp = in_pcblookup_hash(&tcbinfo[0], 1307 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1308 addrs[1].sin6_port, 1309 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1310 addrs[0].sin6_port, 1311 0, NULL); 1312 } else { 1313 inp = in6_pcblookup_hash(&tcbinfo[0], 1314 &addrs[1].sin6_addr, addrs[1].sin6_port, 1315 &addrs[0].sin6_addr, addrs[0].sin6_port, 1316 0, NULL); 1317 } 1318 if (inp == NULL || inp->inp_socket == NULL) { 1319 error = ENOENT; 1320 goto out; 1321 } 1322 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1323 out: 1324 crit_exit(); 1325 return (error); 1326 } 1327 1328 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1329 0, 0, 1330 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1331 #endif 1332 1333 struct netmsg_tcp_notify { 1334 struct netmsg nm_nmsg; 1335 void (*nm_notify)(struct inpcb *, int); 1336 struct in_addr nm_faddr; 1337 int nm_arg; 1338 }; 1339 1340 static void 1341 tcp_notifyall_oncpu(struct netmsg *netmsg) 1342 { 1343 struct netmsg_tcp_notify *nmsg = (struct netmsg_tcp_notify *)netmsg; 1344 int nextcpu; 1345 1346 in_pcbnotifyall(&tcbinfo[mycpuid].pcblisthead, nmsg->nm_faddr, 1347 nmsg->nm_arg, nmsg->nm_notify); 1348 1349 nextcpu = mycpuid + 1; 1350 if (nextcpu < ncpus2) 1351 lwkt_forwardmsg(tcp_cport(nextcpu), &netmsg->nm_lmsg); 1352 else 1353 lwkt_replymsg(&netmsg->nm_lmsg, 0); 1354 } 1355 1356 void 1357 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1358 { 1359 struct ip *ip = vip; 1360 struct tcphdr *th; 1361 struct in_addr faddr; 1362 struct inpcb *inp; 1363 struct tcpcb *tp; 1364 void (*notify)(struct inpcb *, int) = tcp_notify; 1365 tcp_seq icmpseq; 1366 int arg, cpu; 1367 1368 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) { 1369 return; 1370 } 1371 1372 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1373 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1374 return; 1375 1376 arg = inetctlerrmap[cmd]; 1377 if (cmd == PRC_QUENCH) { 1378 notify = tcp_quench; 1379 } else if (icmp_may_rst && 1380 (cmd == PRC_UNREACH_ADMIN_PROHIB || 1381 cmd == PRC_UNREACH_PORT || 1382 cmd == PRC_TIMXCEED_INTRANS) && 1383 ip != NULL) { 1384 notify = tcp_drop_syn_sent; 1385 } else if (cmd == PRC_MSGSIZE) { 1386 struct icmp *icmp = (struct icmp *) 1387 ((caddr_t)ip - offsetof(struct icmp, icmp_ip)); 1388 1389 arg = ntohs(icmp->icmp_nextmtu); 1390 notify = tcp_mtudisc; 1391 } else if (PRC_IS_REDIRECT(cmd)) { 1392 ip = NULL; 1393 notify = in_rtchange; 1394 } else if (cmd == PRC_HOSTDEAD) { 1395 ip = NULL; 1396 } 1397 1398 if (ip != NULL) { 1399 crit_enter(); 1400 th = (struct tcphdr *)((caddr_t)ip + 1401 (IP_VHL_HL(ip->ip_vhl) << 2)); 1402 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1403 ip->ip_src.s_addr, th->th_sport); 1404 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1405 ip->ip_src, th->th_sport, 0, NULL); 1406 if ((inp != NULL) && (inp->inp_socket != NULL)) { 1407 icmpseq = htonl(th->th_seq); 1408 tp = intotcpcb(inp); 1409 if (SEQ_GEQ(icmpseq, tp->snd_una) && 1410 SEQ_LT(icmpseq, tp->snd_max)) 1411 (*notify)(inp, arg); 1412 } else { 1413 struct in_conninfo inc; 1414 1415 inc.inc_fport = th->th_dport; 1416 inc.inc_lport = th->th_sport; 1417 inc.inc_faddr = faddr; 1418 inc.inc_laddr = ip->ip_src; 1419 #ifdef INET6 1420 inc.inc_isipv6 = 0; 1421 #endif 1422 syncache_unreach(&inc, th); 1423 } 1424 crit_exit(); 1425 } else { 1426 struct netmsg_tcp_notify nmsg; 1427 1428 KKASSERT(&curthread->td_msgport == cpu_portfn(0)); 1429 netmsg_init(&nmsg.nm_nmsg, &curthread->td_msgport, 0, 1430 tcp_notifyall_oncpu); 1431 nmsg.nm_faddr = faddr; 1432 nmsg.nm_arg = arg; 1433 nmsg.nm_notify = notify; 1434 1435 lwkt_domsg(tcp_cport(0), &nmsg.nm_nmsg.nm_lmsg, 0); 1436 } 1437 } 1438 1439 #ifdef INET6 1440 void 1441 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1442 { 1443 struct tcphdr th; 1444 void (*notify) (struct inpcb *, int) = tcp_notify; 1445 struct ip6_hdr *ip6; 1446 struct mbuf *m; 1447 struct ip6ctlparam *ip6cp = NULL; 1448 const struct sockaddr_in6 *sa6_src = NULL; 1449 int off; 1450 struct tcp_portonly { 1451 u_int16_t th_sport; 1452 u_int16_t th_dport; 1453 } *thp; 1454 int arg; 1455 1456 if (sa->sa_family != AF_INET6 || 1457 sa->sa_len != sizeof(struct sockaddr_in6)) 1458 return; 1459 1460 arg = 0; 1461 if (cmd == PRC_QUENCH) 1462 notify = tcp_quench; 1463 else if (cmd == PRC_MSGSIZE) { 1464 struct ip6ctlparam *ip6cp = d; 1465 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6; 1466 1467 arg = ntohl(icmp6->icmp6_mtu); 1468 notify = tcp_mtudisc; 1469 } else if (!PRC_IS_REDIRECT(cmd) && 1470 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) { 1471 return; 1472 } 1473 1474 /* if the parameter is from icmp6, decode it. */ 1475 if (d != NULL) { 1476 ip6cp = (struct ip6ctlparam *)d; 1477 m = ip6cp->ip6c_m; 1478 ip6 = ip6cp->ip6c_ip6; 1479 off = ip6cp->ip6c_off; 1480 sa6_src = ip6cp->ip6c_src; 1481 } else { 1482 m = NULL; 1483 ip6 = NULL; 1484 off = 0; /* fool gcc */ 1485 sa6_src = &sa6_any; 1486 } 1487 1488 if (ip6 != NULL) { 1489 struct in_conninfo inc; 1490 /* 1491 * XXX: We assume that when IPV6 is non NULL, 1492 * M and OFF are valid. 1493 */ 1494 1495 /* check if we can safely examine src and dst ports */ 1496 if (m->m_pkthdr.len < off + sizeof *thp) 1497 return; 1498 1499 bzero(&th, sizeof th); 1500 m_copydata(m, off, sizeof *thp, (caddr_t)&th); 1501 1502 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport, 1503 (struct sockaddr *)ip6cp->ip6c_src, 1504 th.th_sport, cmd, arg, notify); 1505 1506 inc.inc_fport = th.th_dport; 1507 inc.inc_lport = th.th_sport; 1508 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1509 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1510 inc.inc_isipv6 = 1; 1511 syncache_unreach(&inc, &th); 1512 } else 1513 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0, 1514 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify); 1515 } 1516 #endif 1517 1518 /* 1519 * Following is where TCP initial sequence number generation occurs. 1520 * 1521 * There are two places where we must use initial sequence numbers: 1522 * 1. In SYN-ACK packets. 1523 * 2. In SYN packets. 1524 * 1525 * All ISNs for SYN-ACK packets are generated by the syncache. See 1526 * tcp_syncache.c for details. 1527 * 1528 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1529 * depends on this property. In addition, these ISNs should be 1530 * unguessable so as to prevent connection hijacking. To satisfy 1531 * the requirements of this situation, the algorithm outlined in 1532 * RFC 1948 is used to generate sequence numbers. 1533 * 1534 * Implementation details: 1535 * 1536 * Time is based off the system timer, and is corrected so that it 1537 * increases by one megabyte per second. This allows for proper 1538 * recycling on high speed LANs while still leaving over an hour 1539 * before rollover. 1540 * 1541 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1542 * between seeding of isn_secret. This is normally set to zero, 1543 * as reseeding should not be necessary. 1544 * 1545 */ 1546 1547 #define ISN_BYTES_PER_SECOND 1048576 1548 1549 u_char isn_secret[32]; 1550 int isn_last_reseed; 1551 MD5_CTX isn_ctx; 1552 1553 tcp_seq 1554 tcp_new_isn(struct tcpcb *tp) 1555 { 1556 u_int32_t md5_buffer[4]; 1557 tcp_seq new_isn; 1558 1559 /* Seed if this is the first use, reseed if requested. */ 1560 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1561 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1562 < (u_int)ticks))) { 1563 read_random_unlimited(&isn_secret, sizeof isn_secret); 1564 isn_last_reseed = ticks; 1565 } 1566 1567 /* Compute the md5 hash and return the ISN. */ 1568 MD5Init(&isn_ctx); 1569 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 1570 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 1571 #ifdef INET6 1572 if (tp->t_inpcb->inp_vflag & INP_IPV6) { 1573 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1574 sizeof(struct in6_addr)); 1575 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1576 sizeof(struct in6_addr)); 1577 } else 1578 #endif 1579 { 1580 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1581 sizeof(struct in_addr)); 1582 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1583 sizeof(struct in_addr)); 1584 } 1585 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1586 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1587 new_isn = (tcp_seq) md5_buffer[0]; 1588 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1589 return (new_isn); 1590 } 1591 1592 /* 1593 * When a source quench is received, close congestion window 1594 * to one segment. We will gradually open it again as we proceed. 1595 */ 1596 void 1597 tcp_quench(struct inpcb *inp, int error) 1598 { 1599 struct tcpcb *tp = intotcpcb(inp); 1600 1601 if (tp != NULL) { 1602 tp->snd_cwnd = tp->t_maxseg; 1603 tp->snd_wacked = 0; 1604 } 1605 } 1606 1607 /* 1608 * When a specific ICMP unreachable message is received and the 1609 * connection state is SYN-SENT, drop the connection. This behavior 1610 * is controlled by the icmp_may_rst sysctl. 1611 */ 1612 void 1613 tcp_drop_syn_sent(struct inpcb *inp, int error) 1614 { 1615 struct tcpcb *tp = intotcpcb(inp); 1616 1617 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT)) 1618 tcp_drop(tp, error); 1619 } 1620 1621 /* 1622 * When a `need fragmentation' ICMP is received, update our idea of the MSS 1623 * based on the new value in the route. Also nudge TCP to send something, 1624 * since we know the packet we just sent was dropped. 1625 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1626 */ 1627 void 1628 tcp_mtudisc(struct inpcb *inp, int mtu) 1629 { 1630 struct tcpcb *tp = intotcpcb(inp); 1631 struct rtentry *rt; 1632 struct socket *so = inp->inp_socket; 1633 int maxopd, mss; 1634 #ifdef INET6 1635 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0); 1636 #else 1637 const boolean_t isipv6 = FALSE; 1638 #endif 1639 1640 if (tp == NULL) 1641 return; 1642 1643 /* 1644 * If no MTU is provided in the ICMP message, use the 1645 * next lower likely value, as specified in RFC 1191. 1646 */ 1647 if (mtu == 0) { 1648 int oldmtu; 1649 1650 oldmtu = tp->t_maxopd + 1651 (isipv6 ? 1652 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1653 sizeof(struct tcpiphdr)); 1654 mtu = ip_next_mtu(oldmtu, 0); 1655 } 1656 1657 if (isipv6) 1658 rt = tcp_rtlookup6(&inp->inp_inc); 1659 else 1660 rt = tcp_rtlookup(&inp->inp_inc); 1661 if (rt != NULL) { 1662 struct rmxp_tao *taop = rmx_taop(rt->rt_rmx); 1663 1664 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu) 1665 mtu = rt->rt_rmx.rmx_mtu; 1666 1667 maxopd = mtu - 1668 (isipv6 ? 1669 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1670 sizeof(struct tcpiphdr)); 1671 1672 /* 1673 * XXX - The following conditional probably violates the TCP 1674 * spec. The problem is that, since we don't know the 1675 * other end's MSS, we are supposed to use a conservative 1676 * default. But, if we do that, then MTU discovery will 1677 * never actually take place, because the conservative 1678 * default is much less than the MTUs typically seen 1679 * on the Internet today. For the moment, we'll sweep 1680 * this under the carpet. 1681 * 1682 * The conservative default might not actually be a problem 1683 * if the only case this occurs is when sending an initial 1684 * SYN with options and data to a host we've never talked 1685 * to before. Then, they will reply with an MSS value which 1686 * will get recorded and the new parameters should get 1687 * recomputed. For Further Study. 1688 */ 1689 if (taop->tao_mssopt != 0 && taop->tao_mssopt < maxopd) 1690 maxopd = taop->tao_mssopt; 1691 } else 1692 maxopd = mtu - 1693 (isipv6 ? 1694 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1695 sizeof(struct tcpiphdr)); 1696 1697 if (tp->t_maxopd <= maxopd) 1698 return; 1699 tp->t_maxopd = maxopd; 1700 1701 mss = maxopd; 1702 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) == 1703 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1704 mss -= TCPOLEN_TSTAMP_APPA; 1705 1706 if ((tp->t_flags & (TF_REQ_CC | TF_RCVD_CC | TF_NOOPT)) == 1707 (TF_REQ_CC | TF_RCVD_CC)) 1708 mss -= TCPOLEN_CC_APPA; 1709 1710 /* round down to multiple of MCLBYTES */ 1711 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */ 1712 if (mss > MCLBYTES) 1713 mss &= ~(MCLBYTES - 1); 1714 #else 1715 if (mss > MCLBYTES) 1716 mss = (mss / MCLBYTES) * MCLBYTES; 1717 #endif 1718 1719 if (so->so_snd.ssb_hiwat < mss) 1720 mss = so->so_snd.ssb_hiwat; 1721 1722 tp->t_maxseg = mss; 1723 tp->t_rtttime = 0; 1724 tp->snd_nxt = tp->snd_una; 1725 tcp_output(tp); 1726 tcpstat.tcps_mturesent++; 1727 } 1728 1729 /* 1730 * Look-up the routing entry to the peer of this inpcb. If no route 1731 * is found and it cannot be allocated the return NULL. This routine 1732 * is called by TCP routines that access the rmx structure and by tcp_mss 1733 * to get the interface MTU. 1734 */ 1735 struct rtentry * 1736 tcp_rtlookup(struct in_conninfo *inc) 1737 { 1738 struct route *ro = &inc->inc_route; 1739 1740 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) { 1741 /* No route yet, so try to acquire one */ 1742 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1743 /* 1744 * unused portions of the structure MUST be zero'd 1745 * out because rtalloc() treats it as opaque data 1746 */ 1747 bzero(&ro->ro_dst, sizeof(struct sockaddr_in)); 1748 ro->ro_dst.sa_family = AF_INET; 1749 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1750 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1751 inc->inc_faddr; 1752 rtalloc(ro); 1753 } 1754 } 1755 return (ro->ro_rt); 1756 } 1757 1758 #ifdef INET6 1759 struct rtentry * 1760 tcp_rtlookup6(struct in_conninfo *inc) 1761 { 1762 struct route_in6 *ro6 = &inc->inc6_route; 1763 1764 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) { 1765 /* No route yet, so try to acquire one */ 1766 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1767 /* 1768 * unused portions of the structure MUST be zero'd 1769 * out because rtalloc() treats it as opaque data 1770 */ 1771 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6)); 1772 ro6->ro_dst.sin6_family = AF_INET6; 1773 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1774 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1775 rtalloc((struct route *)ro6); 1776 } 1777 } 1778 return (ro6->ro_rt); 1779 } 1780 #endif 1781 1782 #ifdef IPSEC 1783 /* compute ESP/AH header size for TCP, including outer IP header. */ 1784 size_t 1785 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1786 { 1787 struct inpcb *inp; 1788 struct mbuf *m; 1789 size_t hdrsiz; 1790 struct ip *ip; 1791 struct tcphdr *th; 1792 1793 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1794 return (0); 1795 MGETHDR(m, MB_DONTWAIT, MT_DATA); 1796 if (!m) 1797 return (0); 1798 1799 #ifdef INET6 1800 if (inp->inp_vflag & INP_IPV6) { 1801 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 1802 1803 th = (struct tcphdr *)(ip6 + 1); 1804 m->m_pkthdr.len = m->m_len = 1805 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1806 tcp_fillheaders(tp, ip6, th); 1807 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1808 } else 1809 #endif 1810 { 1811 ip = mtod(m, struct ip *); 1812 th = (struct tcphdr *)(ip + 1); 1813 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1814 tcp_fillheaders(tp, ip, th); 1815 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1816 } 1817 1818 m_free(m); 1819 return (hdrsiz); 1820 } 1821 #endif 1822 1823 /* 1824 * Return a pointer to the cached information about the remote host. 1825 * The cached information is stored in the protocol specific part of 1826 * the route metrics. 1827 */ 1828 struct rmxp_tao * 1829 tcp_gettaocache(struct in_conninfo *inc) 1830 { 1831 struct rtentry *rt; 1832 1833 #ifdef INET6 1834 if (inc->inc_isipv6) 1835 rt = tcp_rtlookup6(inc); 1836 else 1837 #endif 1838 rt = tcp_rtlookup(inc); 1839 1840 /* Make sure this is a host route and is up. */ 1841 if (rt == NULL || 1842 (rt->rt_flags & (RTF_UP | RTF_HOST)) != (RTF_UP | RTF_HOST)) 1843 return (NULL); 1844 1845 return (rmx_taop(rt->rt_rmx)); 1846 } 1847 1848 /* 1849 * Clear all the TAO cache entries, called from tcp_init. 1850 * 1851 * XXX 1852 * This routine is just an empty one, because we assume that the routing 1853 * routing tables are initialized at the same time when TCP, so there is 1854 * nothing in the cache left over. 1855 */ 1856 static void 1857 tcp_cleartaocache(void) 1858 { 1859 } 1860 1861 /* 1862 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1863 * 1864 * This code attempts to calculate the bandwidth-delay product as a 1865 * means of determining the optimal window size to maximize bandwidth, 1866 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1867 * routers. This code also does a fairly good job keeping RTTs in check 1868 * across slow links like modems. We implement an algorithm which is very 1869 * similar (but not meant to be) TCP/Vegas. The code operates on the 1870 * transmitter side of a TCP connection and so only effects the transmit 1871 * side of the connection. 1872 * 1873 * BACKGROUND: TCP makes no provision for the management of buffer space 1874 * at the end points or at the intermediate routers and switches. A TCP 1875 * stream, whether using NewReno or not, will eventually buffer as 1876 * many packets as it is able and the only reason this typically works is 1877 * due to the fairly small default buffers made available for a connection 1878 * (typicaly 16K or 32K). As machines use larger windows and/or window 1879 * scaling it is now fairly easy for even a single TCP connection to blow-out 1880 * all available buffer space not only on the local interface, but on 1881 * intermediate routers and switches as well. NewReno makes a misguided 1882 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1883 * then backing off, then steadily increasing the window again until another 1884 * failure occurs, ad-infinitum. This results in terrible oscillation that 1885 * is only made worse as network loads increase and the idea of intentionally 1886 * blowing out network buffers is, frankly, a terrible way to manage network 1887 * resources. 1888 * 1889 * It is far better to limit the transmit window prior to the failure 1890 * condition being achieved. There are two general ways to do this: First 1891 * you can 'scan' through different transmit window sizes and locate the 1892 * point where the RTT stops increasing, indicating that you have filled the 1893 * pipe, then scan backwards until you note that RTT stops decreasing, then 1894 * repeat ad-infinitum. This method works in principle but has severe 1895 * implementation issues due to RTT variances, timer granularity, and 1896 * instability in the algorithm which can lead to many false positives and 1897 * create oscillations as well as interact badly with other TCP streams 1898 * implementing the same algorithm. 1899 * 1900 * The second method is to limit the window to the bandwidth delay product 1901 * of the link. This is the method we implement. RTT variances and our 1902 * own manipulation of the congestion window, bwnd, can potentially 1903 * destabilize the algorithm. For this reason we have to stabilize the 1904 * elements used to calculate the window. We do this by using the minimum 1905 * observed RTT, the long term average of the observed bandwidth, and 1906 * by adding two segments worth of slop. It isn't perfect but it is able 1907 * to react to changing conditions and gives us a very stable basis on 1908 * which to extend the algorithm. 1909 */ 1910 void 1911 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1912 { 1913 u_long bw; 1914 u_long bwnd; 1915 int save_ticks; 1916 int delta_ticks; 1917 1918 /* 1919 * If inflight_enable is disabled in the middle of a tcp connection, 1920 * make sure snd_bwnd is effectively disabled. 1921 */ 1922 if (!tcp_inflight_enable) { 1923 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1924 tp->snd_bandwidth = 0; 1925 return; 1926 } 1927 1928 /* 1929 * Validate the delta time. If a connection is new or has been idle 1930 * a long time we have to reset the bandwidth calculator. 1931 */ 1932 save_ticks = ticks; 1933 delta_ticks = save_ticks - tp->t_bw_rtttime; 1934 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) { 1935 tp->t_bw_rtttime = ticks; 1936 tp->t_bw_rtseq = ack_seq; 1937 if (tp->snd_bandwidth == 0) 1938 tp->snd_bandwidth = tcp_inflight_min; 1939 return; 1940 } 1941 if (delta_ticks == 0) 1942 return; 1943 1944 /* 1945 * Sanity check, plus ignore pure window update acks. 1946 */ 1947 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0) 1948 return; 1949 1950 /* 1951 * Figure out the bandwidth. Due to the tick granularity this 1952 * is a very rough number and it MUST be averaged over a fairly 1953 * long period of time. XXX we need to take into account a link 1954 * that is not using all available bandwidth, but for now our 1955 * slop will ramp us up if this case occurs and the bandwidth later 1956 * increases. 1957 */ 1958 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks; 1959 tp->t_bw_rtttime = save_ticks; 1960 tp->t_bw_rtseq = ack_seq; 1961 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1962 1963 tp->snd_bandwidth = bw; 1964 1965 /* 1966 * Calculate the semi-static bandwidth delay product, plus two maximal 1967 * segments. The additional slop puts us squarely in the sweet 1968 * spot and also handles the bandwidth run-up case. Without the 1969 * slop we could be locking ourselves into a lower bandwidth. 1970 * 1971 * Situations Handled: 1972 * (1) Prevents over-queueing of packets on LANs, especially on 1973 * high speed LANs, allowing larger TCP buffers to be 1974 * specified, and also does a good job preventing 1975 * over-queueing of packets over choke points like modems 1976 * (at least for the transmit side). 1977 * 1978 * (2) Is able to handle changing network loads (bandwidth 1979 * drops so bwnd drops, bandwidth increases so bwnd 1980 * increases). 1981 * 1982 * (3) Theoretically should stabilize in the face of multiple 1983 * connections implementing the same algorithm (this may need 1984 * a little work). 1985 * 1986 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1987 * be adjusted with a sysctl but typically only needs to be on 1988 * very slow connections. A value no smaller then 5 should 1989 * be used, but only reduce this default if you have no other 1990 * choice. 1991 */ 1992 1993 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 1994 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + 1995 tcp_inflight_stab * (int)tp->t_maxseg / 10; 1996 #undef USERTT 1997 1998 if (tcp_inflight_debug > 0) { 1999 static int ltime; 2000 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 2001 ltime = ticks; 2002 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 2003 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd); 2004 } 2005 } 2006 if ((long)bwnd < tcp_inflight_min) 2007 bwnd = tcp_inflight_min; 2008 if (bwnd > tcp_inflight_max) 2009 bwnd = tcp_inflight_max; 2010 if ((long)bwnd < tp->t_maxseg * 2) 2011 bwnd = tp->t_maxseg * 2; 2012 tp->snd_bwnd = bwnd; 2013 } 2014