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/socket.h> 89 #include <sys/socketvar.h> 90 #include <sys/protosw.h> 91 #include <sys/random.h> 92 #include <sys/in_cksum.h> 93 #include <sys/ktr.h> 94 95 #include <vm/vm_zone.h> 96 97 #include <net/route.h> 98 #include <net/if.h> 99 #include <net/netisr.h> 100 101 #define _IP_VHL 102 #include <netinet/in.h> 103 #include <netinet/in_systm.h> 104 #include <netinet/ip.h> 105 #include <netinet/ip6.h> 106 #include <netinet/in_pcb.h> 107 #include <netinet6/in6_pcb.h> 108 #include <netinet/in_var.h> 109 #include <netinet/ip_var.h> 110 #include <netinet6/ip6_var.h> 111 #include <netinet/ip_icmp.h> 112 #ifdef INET6 113 #include <netinet/icmp6.h> 114 #endif 115 #include <netinet/tcp.h> 116 #include <netinet/tcp_fsm.h> 117 #include <netinet/tcp_seq.h> 118 #include <netinet/tcp_timer.h> 119 #include <netinet/tcp_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 #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 tcp_callout inp_tp_rexmt; 298 struct tcp_callout inp_tp_persist; 299 struct tcp_callout inp_tp_keep; 300 struct tcp_callout inp_tp_2msl; 301 struct tcp_callout inp_tp_delack; 302 struct netmsg_tcp_timer inp_tp_timermsg; 303 }; 304 #undef ALIGNMENT 305 #undef ALIGNM1 306 307 /* 308 * Tcp initialization 309 */ 310 void 311 tcp_init(void) 312 { 313 struct inpcbporthead *porthashbase; 314 u_long porthashmask; 315 struct vm_zone *ipi_zone; 316 int hashsize = TCBHASHSIZE; 317 int cpu; 318 319 /* 320 * note: tcptemp is used for keepalives, and it is ok for an 321 * allocation to fail so do not specify MPF_INT. 322 */ 323 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp), 324 25, -1, 0, NULL); 325 326 tcp_ccgen = 1; 327 tcp_cleartaocache(); 328 329 tcp_delacktime = TCPTV_DELACK; 330 tcp_keepinit = TCPTV_KEEP_INIT; 331 tcp_keepidle = TCPTV_KEEP_IDLE; 332 tcp_keepintvl = TCPTV_KEEPINTVL; 333 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 334 tcp_msl = TCPTV_MSL; 335 tcp_rexmit_min = TCPTV_MIN; 336 tcp_rexmit_slop = TCPTV_CPU_VAR; 337 338 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); 339 if (!powerof2(hashsize)) { 340 kprintf("WARNING: TCB hash size not a power of 2\n"); 341 hashsize = 512; /* safe default */ 342 } 343 tcp_tcbhashsize = hashsize; 344 porthashbase = hashinit(hashsize, M_PCB, &porthashmask); 345 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 346 ZONE_INTERRUPT, 0); 347 348 for (cpu = 0; cpu < ncpus2; cpu++) { 349 in_pcbinfo_init(&tcbinfo[cpu]); 350 tcbinfo[cpu].cpu = cpu; 351 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB, 352 &tcbinfo[cpu].hashmask); 353 tcbinfo[cpu].porthashbase = porthashbase; 354 tcbinfo[cpu].porthashmask = porthashmask; 355 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB, 356 &tcbinfo[cpu].wildcardhashmask); 357 tcbinfo[cpu].ipi_zone = ipi_zone; 358 TAILQ_INIT(&tcpcbackq[cpu]); 359 } 360 361 tcp_reass_maxseg = nmbclusters / 16; 362 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg); 363 364 #ifdef INET6 365 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) 366 #else 367 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr)) 368 #endif 369 if (max_protohdr < TCP_MINPROTOHDR) 370 max_protohdr = TCP_MINPROTOHDR; 371 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN) 372 panic("tcp_init"); 373 #undef TCP_MINPROTOHDR 374 375 /* 376 * Initialize TCP statistics counters for each CPU. 377 */ 378 #ifdef SMP 379 for (cpu = 0; cpu < ncpus; ++cpu) { 380 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats)); 381 } 382 #else 383 bzero(&tcpstat, sizeof(struct tcp_stats)); 384 #endif 385 386 syncache_init(); 387 tcp_thread_init(); 388 } 389 390 void 391 tcpmsg_service_loop(void *dummy) 392 { 393 struct netmsg *msg; 394 int mplocked; 395 396 /* 397 * Thread was started with TDF_MPSAFE 398 */ 399 mplocked = 0; 400 401 while ((msg = lwkt_waitport(&curthread->td_msgport, 0))) { 402 do { 403 logtcp(rxmsg); 404 mplocked = netmsg_service(msg, tcp_mpsafe_thread, 405 mplocked); 406 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL); 407 408 logtcp(delayed); 409 tcp_willblock(mplocked); 410 logtcp(wait); 411 } 412 } 413 414 static void 415 tcp_willblock(int mplocked) 416 { 417 struct tcpcb *tp; 418 int cpu = mycpu->gd_cpuid; 419 int unlock = 0; 420 421 if (!mplocked && !tcp_mpsafe_proto) { 422 if (TAILQ_EMPTY(&tcpcbackq[cpu])) 423 return; 424 425 get_mplock(); 426 mplocked = 1; 427 unlock = 1; 428 } 429 430 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) { 431 KKASSERT(tp->t_flags & TF_ONOUTPUTQ); 432 tp->t_flags &= ~TF_ONOUTPUTQ; 433 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq); 434 tcp_output(tp); 435 } 436 437 if (unlock) 438 rel_mplock(); 439 } 440 441 442 /* 443 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb. 444 * tcp_template used to store this data in mbufs, but we now recopy it out 445 * of the tcpcb each time to conserve mbufs. 446 */ 447 void 448 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr) 449 { 450 struct inpcb *inp = tp->t_inpcb; 451 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; 452 453 #ifdef INET6 454 if (inp->inp_vflag & INP_IPV6) { 455 struct ip6_hdr *ip6; 456 457 ip6 = (struct ip6_hdr *)ip_ptr; 458 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) | 459 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK); 460 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) | 461 (IPV6_VERSION & IPV6_VERSION_MASK); 462 ip6->ip6_nxt = IPPROTO_TCP; 463 ip6->ip6_plen = sizeof(struct tcphdr); 464 ip6->ip6_src = inp->in6p_laddr; 465 ip6->ip6_dst = inp->in6p_faddr; 466 tcp_hdr->th_sum = 0; 467 } else 468 #endif 469 { 470 struct ip *ip = (struct ip *) ip_ptr; 471 472 ip->ip_vhl = IP_VHL_BORING; 473 ip->ip_tos = 0; 474 ip->ip_len = 0; 475 ip->ip_id = 0; 476 ip->ip_off = 0; 477 ip->ip_ttl = 0; 478 ip->ip_sum = 0; 479 ip->ip_p = IPPROTO_TCP; 480 ip->ip_src = inp->inp_laddr; 481 ip->ip_dst = inp->inp_faddr; 482 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, 483 ip->ip_dst.s_addr, 484 htons(sizeof(struct tcphdr) + IPPROTO_TCP)); 485 } 486 487 tcp_hdr->th_sport = inp->inp_lport; 488 tcp_hdr->th_dport = inp->inp_fport; 489 tcp_hdr->th_seq = 0; 490 tcp_hdr->th_ack = 0; 491 tcp_hdr->th_x2 = 0; 492 tcp_hdr->th_off = 5; 493 tcp_hdr->th_flags = 0; 494 tcp_hdr->th_win = 0; 495 tcp_hdr->th_urp = 0; 496 } 497 498 /* 499 * Create template to be used to send tcp packets on a connection. 500 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only 501 * use for this function is in keepalives, which use tcp_respond. 502 */ 503 struct tcptemp * 504 tcp_maketemplate(struct tcpcb *tp) 505 { 506 struct tcptemp *tmp; 507 508 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL) 509 return (NULL); 510 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t); 511 return (tmp); 512 } 513 514 void 515 tcp_freetemplate(struct tcptemp *tmp) 516 { 517 mpipe_free(&tcptemp_mpipe, tmp); 518 } 519 520 /* 521 * Send a single message to the TCP at address specified by 522 * the given TCP/IP header. If m == NULL, then we make a copy 523 * of the tcpiphdr at ti and send directly to the addressed host. 524 * This is used to force keep alive messages out using the TCP 525 * template for a connection. If flags are given then we send 526 * a message back to the TCP which originated the * segment ti, 527 * and discard the mbuf containing it and any other attached mbufs. 528 * 529 * In any case the ack and sequence number of the transmitted 530 * segment are as specified by the parameters. 531 * 532 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 533 */ 534 void 535 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m, 536 tcp_seq ack, tcp_seq seq, int flags) 537 { 538 int tlen; 539 int win = 0; 540 struct route *ro = NULL; 541 struct route sro; 542 struct ip *ip = ipgen; 543 struct tcphdr *nth; 544 int ipflags = 0; 545 struct route_in6 *ro6 = NULL; 546 struct route_in6 sro6; 547 struct ip6_hdr *ip6 = ipgen; 548 boolean_t use_tmpro = TRUE; 549 #ifdef INET6 550 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6); 551 #else 552 const boolean_t isipv6 = FALSE; 553 #endif 554 555 if (tp != NULL) { 556 if (!(flags & TH_RST)) { 557 win = ssb_space(&tp->t_inpcb->inp_socket->so_rcv); 558 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 559 win = (long)TCP_MAXWIN << tp->rcv_scale; 560 } 561 /* 562 * Don't use the route cache of a listen socket, 563 * it is not MPSAFE; use temporary route cache. 564 */ 565 if (tp->t_state != TCPS_LISTEN) { 566 if (isipv6) 567 ro6 = &tp->t_inpcb->in6p_route; 568 else 569 ro = &tp->t_inpcb->inp_route; 570 use_tmpro = FALSE; 571 } 572 } 573 if (use_tmpro) { 574 if (isipv6) { 575 ro6 = &sro6; 576 bzero(ro6, sizeof *ro6); 577 } else { 578 ro = &sro; 579 bzero(ro, sizeof *ro); 580 } 581 } 582 if (m == NULL) { 583 m = m_gethdr(MB_DONTWAIT, MT_HEADER); 584 if (m == NULL) 585 return; 586 tlen = 0; 587 m->m_data += max_linkhdr; 588 if (isipv6) { 589 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr)); 590 ip6 = mtod(m, struct ip6_hdr *); 591 nth = (struct tcphdr *)(ip6 + 1); 592 } else { 593 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip)); 594 ip = mtod(m, struct ip *); 595 nth = (struct tcphdr *)(ip + 1); 596 } 597 bcopy(th, nth, sizeof(struct tcphdr)); 598 flags = TH_ACK; 599 } else { 600 m_freem(m->m_next); 601 m->m_next = NULL; 602 m->m_data = (caddr_t)ipgen; 603 /* m_len is set later */ 604 tlen = 0; 605 #define xchg(a, b, type) { type t; t = a; a = b; b = t; } 606 if (isipv6) { 607 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr); 608 nth = (struct tcphdr *)(ip6 + 1); 609 } else { 610 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long); 611 nth = (struct tcphdr *)(ip + 1); 612 } 613 if (th != nth) { 614 /* 615 * this is usually a case when an extension header 616 * exists between the IPv6 header and the 617 * TCP header. 618 */ 619 nth->th_sport = th->th_sport; 620 nth->th_dport = th->th_dport; 621 } 622 xchg(nth->th_dport, nth->th_sport, n_short); 623 #undef xchg 624 } 625 if (isipv6) { 626 ip6->ip6_flow = 0; 627 ip6->ip6_vfc = IPV6_VERSION; 628 ip6->ip6_nxt = IPPROTO_TCP; 629 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen)); 630 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 631 } else { 632 tlen += sizeof(struct tcpiphdr); 633 ip->ip_len = tlen; 634 ip->ip_ttl = ip_defttl; 635 } 636 m->m_len = tlen; 637 m->m_pkthdr.len = tlen; 638 m->m_pkthdr.rcvif = (struct ifnet *) NULL; 639 nth->th_seq = htonl(seq); 640 nth->th_ack = htonl(ack); 641 nth->th_x2 = 0; 642 nth->th_off = sizeof(struct tcphdr) >> 2; 643 nth->th_flags = flags; 644 if (tp != NULL) 645 nth->th_win = htons((u_short) (win >> tp->rcv_scale)); 646 else 647 nth->th_win = htons((u_short)win); 648 nth->th_urp = 0; 649 if (isipv6) { 650 nth->th_sum = 0; 651 nth->th_sum = in6_cksum(m, IPPROTO_TCP, 652 sizeof(struct ip6_hdr), 653 tlen - sizeof(struct ip6_hdr)); 654 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, 655 (ro6 && ro6->ro_rt) ? 656 ro6->ro_rt->rt_ifp : NULL); 657 } else { 658 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 659 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p))); 660 m->m_pkthdr.csum_flags = CSUM_TCP; 661 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); 662 } 663 #ifdef TCPDEBUG 664 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 665 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); 666 #endif 667 if (isipv6) { 668 ip6_output(m, NULL, ro6, ipflags, NULL, NULL, 669 tp ? tp->t_inpcb : NULL); 670 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) { 671 RTFREE(ro6->ro_rt); 672 ro6->ro_rt = NULL; 673 } 674 } else { 675 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL); 676 if ((ro == &sro) && (ro->ro_rt != NULL)) { 677 RTFREE(ro->ro_rt); 678 ro->ro_rt = NULL; 679 } 680 } 681 } 682 683 /* 684 * Create a new TCP control block, making an 685 * empty reassembly queue and hooking it to the argument 686 * protocol control block. The `inp' parameter must have 687 * come from the zone allocator set up in tcp_init(). 688 */ 689 struct tcpcb * 690 tcp_newtcpcb(struct inpcb *inp) 691 { 692 struct inp_tp *it; 693 struct tcpcb *tp; 694 #ifdef INET6 695 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 696 #else 697 const boolean_t isipv6 = FALSE; 698 #endif 699 700 it = (struct inp_tp *)inp; 701 tp = &it->tcb; 702 bzero(tp, sizeof(struct tcpcb)); 703 LIST_INIT(&tp->t_segq); 704 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt; 705 706 /* Set up our timeouts. */ 707 tp->tt_rexmt = &it->inp_tp_rexmt; 708 tp->tt_persist = &it->inp_tp_persist; 709 tp->tt_keep = &it->inp_tp_keep; 710 tp->tt_2msl = &it->inp_tp_2msl; 711 tp->tt_delack = &it->inp_tp_delack; 712 tcp_inittimers(tp); 713 714 tp->tt_msg = &it->inp_tp_timermsg; 715 if (isipv6) { 716 /* Don't mess with IPv6; always create timer message */ 717 tcp_create_timermsg(tp); 718 } else { 719 /* 720 * Zero out timer message. We don't create it here, 721 * since the current CPU may not be the owner of this 722 * inpcb. 723 */ 724 bzero(tp->tt_msg, sizeof(*tp->tt_msg)); 725 } 726 727 if (tcp_do_rfc1323) 728 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP); 729 if (tcp_do_rfc1644) 730 tp->t_flags |= TF_REQ_CC; 731 tp->t_inpcb = inp; /* XXX */ 732 tp->t_state = TCPS_CLOSED; 733 /* 734 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 735 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 736 * reasonable initial retransmit time. 737 */ 738 tp->t_srtt = TCPTV_SRTTBASE; 739 tp->t_rttvar = 740 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 741 tp->t_rttmin = tcp_rexmit_min; 742 tp->t_rxtcur = TCPTV_RTOBASE; 743 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 744 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 745 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 746 tp->t_rcvtime = ticks; 747 /* 748 * IPv4 TTL initialization is necessary for an IPv6 socket as well, 749 * because the socket may be bound to an IPv6 wildcard address, 750 * which may match an IPv4-mapped IPv6 address. 751 */ 752 inp->inp_ip_ttl = ip_defttl; 753 inp->inp_ppcb = tp; 754 tcp_sack_tcpcb_init(tp); 755 return (tp); /* XXX */ 756 } 757 758 /* 759 * Drop a TCP connection, reporting the specified error. 760 * If connection is synchronized, then send a RST to peer. 761 */ 762 struct tcpcb * 763 tcp_drop(struct tcpcb *tp, int error) 764 { 765 struct socket *so = tp->t_inpcb->inp_socket; 766 767 if (TCPS_HAVERCVDSYN(tp->t_state)) { 768 tp->t_state = TCPS_CLOSED; 769 tcp_output(tp); 770 tcpstat.tcps_drops++; 771 } else 772 tcpstat.tcps_conndrops++; 773 if (error == ETIMEDOUT && tp->t_softerror) 774 error = tp->t_softerror; 775 so->so_error = error; 776 return (tcp_close(tp)); 777 } 778 779 #ifdef SMP 780 781 struct netmsg_remwildcard { 782 struct netmsg nm_netmsg; 783 struct inpcb *nm_inp; 784 struct inpcbinfo *nm_pcbinfo; 785 #if defined(INET6) 786 int nm_isinet6; 787 #else 788 int nm_unused01; 789 #endif 790 }; 791 792 /* 793 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the 794 * inp can be detached. We do this by cycling through the cpus, ending up 795 * on the cpu controlling the inp last and then doing the disconnect. 796 */ 797 static void 798 in_pcbremwildcardhash_handler(struct netmsg *msg0) 799 { 800 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0; 801 int cpu; 802 803 cpu = msg->nm_pcbinfo->cpu; 804 805 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) { 806 /* note: detach removes any wildcard hash entry */ 807 #ifdef INET6 808 if (msg->nm_isinet6) 809 in6_pcbdetach(msg->nm_inp); 810 else 811 #endif 812 in_pcbdetach(msg->nm_inp); 813 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0); 814 } else { 815 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo); 816 cpu = (cpu + 1) % ncpus2; 817 msg->nm_pcbinfo = &tcbinfo[cpu]; 818 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 819 } 820 } 821 822 #endif 823 824 /* 825 * Close a TCP control block: 826 * discard all space held by the tcp 827 * discard internet protocol block 828 * wake up any sleepers 829 */ 830 struct tcpcb * 831 tcp_close(struct tcpcb *tp) 832 { 833 struct tseg_qent *q; 834 struct inpcb *inp = tp->t_inpcb; 835 struct socket *so = inp->inp_socket; 836 struct rtentry *rt; 837 boolean_t dosavessthresh; 838 #ifdef SMP 839 int cpu; 840 #endif 841 #ifdef INET6 842 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0); 843 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0); 844 #else 845 const boolean_t isipv6 = FALSE; 846 #endif 847 848 /* 849 * The tp is not instantly destroyed in the wildcard case. Setting 850 * the state to TCPS_TERMINATING will prevent the TCP stack from 851 * messing with it, though it should be noted that this change may 852 * not take effect on other cpus until we have chained the wildcard 853 * hash removal. 854 * 855 * XXX we currently depend on the BGL to synchronize the tp->t_state 856 * update and prevent other tcp protocol threads from accepting new 857 * connections on the listen socket we might be trying to close down. 858 */ 859 KKASSERT(tp->t_state != TCPS_TERMINATING); 860 tp->t_state = TCPS_TERMINATING; 861 862 /* 863 * Make sure that all of our timers are stopped before we 864 * delete the PCB. For listen TCP socket (tp->tt_msg == NULL), 865 * timers are never used. 866 */ 867 if (tp->tt_msg != NULL) { 868 tcp_callout_stop(tp, tp->tt_rexmt); 869 tcp_callout_stop(tp, tp->tt_persist); 870 tcp_callout_stop(tp, tp->tt_keep); 871 tcp_callout_stop(tp, tp->tt_2msl); 872 tcp_callout_stop(tp, tp->tt_delack); 873 } 874 875 if (tp->t_flags & TF_ONOUTPUTQ) { 876 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid); 877 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq); 878 tp->t_flags &= ~TF_ONOUTPUTQ; 879 } 880 881 /* 882 * If we got enough samples through the srtt filter, 883 * save the rtt and rttvar in the routing entry. 884 * 'Enough' is arbitrarily defined as the 16 samples. 885 * 16 samples is enough for the srtt filter to converge 886 * to within 5% of the correct value; fewer samples and 887 * we could save a very bogus rtt. 888 * 889 * Don't update the default route's characteristics and don't 890 * update anything that the user "locked". 891 */ 892 if (tp->t_rttupdated >= 16) { 893 u_long i = 0; 894 895 if (isipv6) { 896 struct sockaddr_in6 *sin6; 897 898 if ((rt = inp->in6p_route.ro_rt) == NULL) 899 goto no_valid_rt; 900 sin6 = (struct sockaddr_in6 *)rt_key(rt); 901 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) 902 goto no_valid_rt; 903 } else 904 if ((rt = inp->inp_route.ro_rt) == NULL || 905 ((struct sockaddr_in *)rt_key(rt))-> 906 sin_addr.s_addr == INADDR_ANY) 907 goto no_valid_rt; 908 909 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) { 910 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 911 if (rt->rt_rmx.rmx_rtt && i) 912 /* 913 * filter this update to half the old & half 914 * the new values, converting scale. 915 * See route.h and tcp_var.h for a 916 * description of the scaling constants. 917 */ 918 rt->rt_rmx.rmx_rtt = 919 (rt->rt_rmx.rmx_rtt + i) / 2; 920 else 921 rt->rt_rmx.rmx_rtt = i; 922 tcpstat.tcps_cachedrtt++; 923 } 924 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) { 925 i = tp->t_rttvar * 926 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 927 if (rt->rt_rmx.rmx_rttvar && i) 928 rt->rt_rmx.rmx_rttvar = 929 (rt->rt_rmx.rmx_rttvar + i) / 2; 930 else 931 rt->rt_rmx.rmx_rttvar = i; 932 tcpstat.tcps_cachedrttvar++; 933 } 934 /* 935 * The old comment here said: 936 * update the pipelimit (ssthresh) if it has been updated 937 * already or if a pipesize was specified & the threshhold 938 * got below half the pipesize. I.e., wait for bad news 939 * before we start updating, then update on both good 940 * and bad news. 941 * 942 * But we want to save the ssthresh even if no pipesize is 943 * specified explicitly in the route, because such 944 * connections still have an implicit pipesize specified 945 * by the global tcp_sendspace. In the absence of a reliable 946 * way to calculate the pipesize, it will have to do. 947 */ 948 i = tp->snd_ssthresh; 949 if (rt->rt_rmx.rmx_sendpipe != 0) 950 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2); 951 else 952 dosavessthresh = (i < so->so_snd.ssb_hiwat/2); 953 if (dosavessthresh || 954 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) && 955 (rt->rt_rmx.rmx_ssthresh != 0))) { 956 /* 957 * convert the limit from user data bytes to 958 * packets then to packet data bytes. 959 */ 960 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 961 if (i < 2) 962 i = 2; 963 i *= tp->t_maxseg + 964 (isipv6 ? 965 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 966 sizeof(struct tcpiphdr)); 967 if (rt->rt_rmx.rmx_ssthresh) 968 rt->rt_rmx.rmx_ssthresh = 969 (rt->rt_rmx.rmx_ssthresh + i) / 2; 970 else 971 rt->rt_rmx.rmx_ssthresh = i; 972 tcpstat.tcps_cachedssthresh++; 973 } 974 } 975 976 no_valid_rt: 977 /* free the reassembly queue, if any */ 978 while((q = LIST_FIRST(&tp->t_segq)) != NULL) { 979 LIST_REMOVE(q, tqe_q); 980 m_freem(q->tqe_m); 981 FREE(q, M_TSEGQ); 982 tcp_reass_qsize--; 983 } 984 /* throw away SACK blocks in scoreboard*/ 985 if (TCP_DO_SACK(tp)) 986 tcp_sack_cleanup(&tp->scb); 987 988 inp->inp_ppcb = NULL; 989 soisdisconnected(so); 990 991 tcp_destroy_timermsg(tp); 992 993 /* 994 * Discard the inp. In the SMP case a wildcard inp's hash (created 995 * by a listen socket or an INADDR_ANY udp socket) is replicated 996 * for each protocol thread and must be removed in the context of 997 * that thread. This is accomplished by chaining the message 998 * through the cpus. 999 * 1000 * If the inp is not wildcarded we simply detach, which will remove 1001 * the any hashes still present for this inp. 1002 */ 1003 #ifdef SMP 1004 if (inp->inp_flags & INP_WILDCARD_MP) { 1005 struct netmsg_remwildcard *msg; 1006 1007 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2; 1008 msg = kmalloc(sizeof(struct netmsg_remwildcard), 1009 M_LWKTMSG, M_INTWAIT); 1010 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0, 1011 in_pcbremwildcardhash_handler); 1012 #ifdef INET6 1013 msg->nm_isinet6 = isafinet6; 1014 #endif 1015 msg->nm_inp = inp; 1016 msg->nm_pcbinfo = &tcbinfo[cpu]; 1017 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1018 } else 1019 #endif 1020 { 1021 /* note: detach removes any wildcard hash entry */ 1022 #ifdef INET6 1023 if (isafinet6) 1024 in6_pcbdetach(inp); 1025 else 1026 #endif 1027 in_pcbdetach(inp); 1028 } 1029 tcpstat.tcps_closed++; 1030 return (NULL); 1031 } 1032 1033 static __inline void 1034 tcp_drain_oncpu(struct inpcbhead *head) 1035 { 1036 struct inpcb *inpb; 1037 struct tcpcb *tcpb; 1038 struct tseg_qent *te; 1039 1040 LIST_FOREACH(inpb, head, inp_list) { 1041 if (inpb->inp_flags & INP_PLACEMARKER) 1042 continue; 1043 if ((tcpb = intotcpcb(inpb))) { 1044 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) { 1045 LIST_REMOVE(te, tqe_q); 1046 m_freem(te->tqe_m); 1047 FREE(te, M_TSEGQ); 1048 tcp_reass_qsize--; 1049 } 1050 } 1051 } 1052 } 1053 1054 #ifdef SMP 1055 struct netmsg_tcp_drain { 1056 struct netmsg nm_netmsg; 1057 struct inpcbhead *nm_head; 1058 }; 1059 1060 static void 1061 tcp_drain_handler(netmsg_t netmsg) 1062 { 1063 struct netmsg_tcp_drain *nm = (void *)netmsg; 1064 1065 tcp_drain_oncpu(nm->nm_head); 1066 lwkt_replymsg(&nm->nm_netmsg.nm_lmsg, 0); 1067 } 1068 #endif 1069 1070 void 1071 tcp_drain(void) 1072 { 1073 #ifdef SMP 1074 int cpu; 1075 #endif 1076 1077 if (!do_tcpdrain) 1078 return; 1079 1080 /* 1081 * Walk the tcpbs, if existing, and flush the reassembly queue, 1082 * if there is one... 1083 * XXX: The "Net/3" implementation doesn't imply that the TCP 1084 * reassembly queue should be flushed, but in a situation 1085 * where we're really low on mbufs, this is potentially 1086 * useful. 1087 */ 1088 #ifdef SMP 1089 for (cpu = 0; cpu < ncpus2; cpu++) { 1090 struct netmsg_tcp_drain *msg; 1091 1092 if (cpu == mycpu->gd_cpuid) { 1093 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead); 1094 } else { 1095 msg = kmalloc(sizeof(struct netmsg_tcp_drain), 1096 M_LWKTMSG, M_NOWAIT); 1097 if (msg == NULL) 1098 continue; 1099 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0, 1100 tcp_drain_handler); 1101 msg->nm_head = &tcbinfo[cpu].pcblisthead; 1102 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg); 1103 } 1104 } 1105 #else 1106 tcp_drain_oncpu(&tcbinfo[0].pcblisthead); 1107 #endif 1108 } 1109 1110 /* 1111 * Notify a tcp user of an asynchronous error; 1112 * store error as soft error, but wake up user 1113 * (for now, won't do anything until can select for soft error). 1114 * 1115 * Do not wake up user since there currently is no mechanism for 1116 * reporting soft errors (yet - a kqueue filter may be added). 1117 */ 1118 static void 1119 tcp_notify(struct inpcb *inp, int error) 1120 { 1121 struct tcpcb *tp = intotcpcb(inp); 1122 1123 /* 1124 * Ignore some errors if we are hooked up. 1125 * If connection hasn't completed, has retransmitted several times, 1126 * and receives a second error, give up now. This is better 1127 * than waiting a long time to establish a connection that 1128 * can never complete. 1129 */ 1130 if (tp->t_state == TCPS_ESTABLISHED && 1131 (error == EHOSTUNREACH || error == ENETUNREACH || 1132 error == EHOSTDOWN)) { 1133 return; 1134 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 1135 tp->t_softerror) 1136 tcp_drop(tp, error); 1137 else 1138 tp->t_softerror = error; 1139 #if 0 1140 wakeup(&so->so_timeo); 1141 sorwakeup(so); 1142 sowwakeup(so); 1143 #endif 1144 } 1145 1146 static int 1147 tcp_pcblist(SYSCTL_HANDLER_ARGS) 1148 { 1149 int error, i, n; 1150 struct inpcb *marker; 1151 struct inpcb *inp; 1152 inp_gen_t gencnt; 1153 globaldata_t gd; 1154 int origcpu, ccpu; 1155 1156 error = 0; 1157 n = 0; 1158 1159 /* 1160 * The process of preparing the TCB list is too time-consuming and 1161 * resource-intensive to repeat twice on every request. 1162 */ 1163 if (req->oldptr == NULL) { 1164 for (ccpu = 0; ccpu < ncpus; ++ccpu) { 1165 gd = globaldata_find(ccpu); 1166 n += tcbinfo[gd->gd_cpuid].ipi_count; 1167 } 1168 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb); 1169 return (0); 1170 } 1171 1172 if (req->newptr != NULL) 1173 return (EPERM); 1174 1175 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO); 1176 marker->inp_flags |= INP_PLACEMARKER; 1177 1178 /* 1179 * OK, now we're committed to doing something. Run the inpcb list 1180 * for each cpu in the system and construct the output. Use a 1181 * list placemarker to deal with list changes occuring during 1182 * copyout blockages (but otherwise depend on being on the correct 1183 * cpu to avoid races). 1184 */ 1185 origcpu = mycpu->gd_cpuid; 1186 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) { 1187 globaldata_t rgd; 1188 caddr_t inp_ppcb; 1189 struct xtcpcb xt; 1190 int cpu_id; 1191 1192 cpu_id = (origcpu + ccpu) % ncpus; 1193 if ((smp_active_mask & (1 << cpu_id)) == 0) 1194 continue; 1195 rgd = globaldata_find(cpu_id); 1196 lwkt_setcpu_self(rgd); 1197 1198 gencnt = tcbinfo[cpu_id].ipi_gencnt; 1199 n = tcbinfo[cpu_id].ipi_count; 1200 1201 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list); 1202 i = 0; 1203 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) { 1204 /* 1205 * process a snapshot of pcbs, ignoring placemarkers 1206 * and using our own to allow SYSCTL_OUT to block. 1207 */ 1208 LIST_REMOVE(marker, inp_list); 1209 LIST_INSERT_AFTER(inp, marker, inp_list); 1210 1211 if (inp->inp_flags & INP_PLACEMARKER) 1212 continue; 1213 if (inp->inp_gencnt > gencnt) 1214 continue; 1215 if (prison_xinpcb(req->td, inp)) 1216 continue; 1217 1218 xt.xt_len = sizeof xt; 1219 bcopy(inp, &xt.xt_inp, sizeof *inp); 1220 inp_ppcb = inp->inp_ppcb; 1221 if (inp_ppcb != NULL) 1222 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 1223 else 1224 bzero(&xt.xt_tp, sizeof xt.xt_tp); 1225 if (inp->inp_socket) 1226 sotoxsocket(inp->inp_socket, &xt.xt_socket); 1227 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0) 1228 break; 1229 ++i; 1230 } 1231 LIST_REMOVE(marker, inp_list); 1232 if (error == 0 && i < n) { 1233 bzero(&xt, sizeof xt); 1234 xt.xt_len = sizeof xt; 1235 while (i < n) { 1236 error = SYSCTL_OUT(req, &xt, sizeof xt); 1237 if (error) 1238 break; 1239 ++i; 1240 } 1241 } 1242 } 1243 1244 /* 1245 * Make sure we are on the same cpu we were on originally, since 1246 * higher level callers expect this. Also don't pollute caches with 1247 * migrated userland data by (eventually) returning to userland 1248 * on a different cpu. 1249 */ 1250 lwkt_setcpu_self(globaldata_find(origcpu)); 1251 kfree(marker, M_TEMP); 1252 return (error); 1253 } 1254 1255 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 1256 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 1257 1258 static int 1259 tcp_getcred(SYSCTL_HANDLER_ARGS) 1260 { 1261 struct sockaddr_in addrs[2]; 1262 struct inpcb *inp; 1263 int cpu; 1264 int error; 1265 1266 error = suser(req->td); 1267 if (error != 0) 1268 return (error); 1269 error = SYSCTL_IN(req, addrs, sizeof addrs); 1270 if (error != 0) 1271 return (error); 1272 crit_enter(); 1273 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port, 1274 addrs[0].sin_addr.s_addr, addrs[0].sin_port); 1275 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr, 1276 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 1277 if (inp == NULL || inp->inp_socket == NULL) { 1278 error = ENOENT; 1279 goto out; 1280 } 1281 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1282 out: 1283 crit_exit(); 1284 return (error); 1285 } 1286 1287 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1288 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 1289 1290 #ifdef INET6 1291 static int 1292 tcp6_getcred(SYSCTL_HANDLER_ARGS) 1293 { 1294 struct sockaddr_in6 addrs[2]; 1295 struct inpcb *inp; 1296 int error; 1297 boolean_t mapped = FALSE; 1298 1299 error = suser(req->td); 1300 if (error != 0) 1301 return (error); 1302 error = SYSCTL_IN(req, addrs, sizeof addrs); 1303 if (error != 0) 1304 return (error); 1305 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) { 1306 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr)) 1307 mapped = TRUE; 1308 else 1309 return (EINVAL); 1310 } 1311 crit_enter(); 1312 if (mapped) { 1313 inp = in_pcblookup_hash(&tcbinfo[0], 1314 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12], 1315 addrs[1].sin6_port, 1316 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12], 1317 addrs[0].sin6_port, 1318 0, NULL); 1319 } else { 1320 inp = in6_pcblookup_hash(&tcbinfo[0], 1321 &addrs[1].sin6_addr, addrs[1].sin6_port, 1322 &addrs[0].sin6_addr, addrs[0].sin6_port, 1323 0, NULL); 1324 } 1325 if (inp == NULL || inp->inp_socket == NULL) { 1326 error = ENOENT; 1327 goto out; 1328 } 1329 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 1330 out: 1331 crit_exit(); 1332 return (error); 1333 } 1334 1335 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW), 1336 0, 0, 1337 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection"); 1338 #endif 1339 1340 struct netmsg_tcp_notify { 1341 struct netmsg nm_nmsg; 1342 void (*nm_notify)(struct inpcb *, int); 1343 struct in_addr nm_faddr; 1344 int nm_arg; 1345 }; 1346 1347 static void 1348 tcp_notifyall_oncpu(struct netmsg *netmsg) 1349 { 1350 struct netmsg_tcp_notify *nmsg = (struct netmsg_tcp_notify *)netmsg; 1351 int nextcpu; 1352 1353 in_pcbnotifyall(&tcbinfo[mycpuid].pcblisthead, nmsg->nm_faddr, 1354 nmsg->nm_arg, nmsg->nm_notify); 1355 1356 nextcpu = mycpuid + 1; 1357 if (nextcpu < ncpus2) 1358 lwkt_forwardmsg(tcp_cport(nextcpu), &netmsg->nm_lmsg); 1359 else 1360 lwkt_replymsg(&netmsg->nm_lmsg, 0); 1361 } 1362 1363 void 1364 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip) 1365 { 1366 struct ip *ip = vip; 1367 struct tcphdr *th; 1368 struct in_addr faddr; 1369 struct inpcb *inp; 1370 struct tcpcb *tp; 1371 void (*notify)(struct inpcb *, int) = tcp_notify; 1372 tcp_seq icmpseq; 1373 int arg, cpu; 1374 1375 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) { 1376 return; 1377 } 1378 1379 faddr = ((struct sockaddr_in *)sa)->sin_addr; 1380 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) 1381 return; 1382 1383 arg = inetctlerrmap[cmd]; 1384 if (cmd == PRC_QUENCH) { 1385 notify = tcp_quench; 1386 } else if (icmp_may_rst && 1387 (cmd == PRC_UNREACH_ADMIN_PROHIB || 1388 cmd == PRC_UNREACH_PORT || 1389 cmd == PRC_TIMXCEED_INTRANS) && 1390 ip != NULL) { 1391 notify = tcp_drop_syn_sent; 1392 } else if (cmd == PRC_MSGSIZE) { 1393 struct icmp *icmp = (struct icmp *) 1394 ((caddr_t)ip - offsetof(struct icmp, icmp_ip)); 1395 1396 arg = ntohs(icmp->icmp_nextmtu); 1397 notify = tcp_mtudisc; 1398 } else if (PRC_IS_REDIRECT(cmd)) { 1399 ip = NULL; 1400 notify = in_rtchange; 1401 } else if (cmd == PRC_HOSTDEAD) { 1402 ip = NULL; 1403 } 1404 1405 if (ip != NULL) { 1406 crit_enter(); 1407 th = (struct tcphdr *)((caddr_t)ip + 1408 (IP_VHL_HL(ip->ip_vhl) << 2)); 1409 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport, 1410 ip->ip_src.s_addr, th->th_sport); 1411 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport, 1412 ip->ip_src, th->th_sport, 0, NULL); 1413 if ((inp != NULL) && (inp->inp_socket != NULL)) { 1414 icmpseq = htonl(th->th_seq); 1415 tp = intotcpcb(inp); 1416 if (SEQ_GEQ(icmpseq, tp->snd_una) && 1417 SEQ_LT(icmpseq, tp->snd_max)) 1418 (*notify)(inp, arg); 1419 } else { 1420 struct in_conninfo inc; 1421 1422 inc.inc_fport = th->th_dport; 1423 inc.inc_lport = th->th_sport; 1424 inc.inc_faddr = faddr; 1425 inc.inc_laddr = ip->ip_src; 1426 #ifdef INET6 1427 inc.inc_isipv6 = 0; 1428 #endif 1429 syncache_unreach(&inc, th); 1430 } 1431 crit_exit(); 1432 } else { 1433 struct netmsg_tcp_notify nmsg; 1434 1435 KKASSERT(&curthread->td_msgport == cpu_portfn(0)); 1436 netmsg_init(&nmsg.nm_nmsg, &curthread->td_msgport, 0, 1437 tcp_notifyall_oncpu); 1438 nmsg.nm_faddr = faddr; 1439 nmsg.nm_arg = arg; 1440 nmsg.nm_notify = notify; 1441 1442 lwkt_domsg(tcp_cport(0), &nmsg.nm_nmsg.nm_lmsg, 0); 1443 } 1444 } 1445 1446 #ifdef INET6 1447 void 1448 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d) 1449 { 1450 struct tcphdr th; 1451 void (*notify) (struct inpcb *, int) = tcp_notify; 1452 struct ip6_hdr *ip6; 1453 struct mbuf *m; 1454 struct ip6ctlparam *ip6cp = NULL; 1455 const struct sockaddr_in6 *sa6_src = NULL; 1456 int off; 1457 struct tcp_portonly { 1458 u_int16_t th_sport; 1459 u_int16_t th_dport; 1460 } *thp; 1461 int arg; 1462 1463 if (sa->sa_family != AF_INET6 || 1464 sa->sa_len != sizeof(struct sockaddr_in6)) 1465 return; 1466 1467 arg = 0; 1468 if (cmd == PRC_QUENCH) 1469 notify = tcp_quench; 1470 else if (cmd == PRC_MSGSIZE) { 1471 struct ip6ctlparam *ip6cp = d; 1472 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6; 1473 1474 arg = ntohl(icmp6->icmp6_mtu); 1475 notify = tcp_mtudisc; 1476 } else if (!PRC_IS_REDIRECT(cmd) && 1477 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) { 1478 return; 1479 } 1480 1481 /* if the parameter is from icmp6, decode it. */ 1482 if (d != NULL) { 1483 ip6cp = (struct ip6ctlparam *)d; 1484 m = ip6cp->ip6c_m; 1485 ip6 = ip6cp->ip6c_ip6; 1486 off = ip6cp->ip6c_off; 1487 sa6_src = ip6cp->ip6c_src; 1488 } else { 1489 m = NULL; 1490 ip6 = NULL; 1491 off = 0; /* fool gcc */ 1492 sa6_src = &sa6_any; 1493 } 1494 1495 if (ip6 != NULL) { 1496 struct in_conninfo inc; 1497 /* 1498 * XXX: We assume that when IPV6 is non NULL, 1499 * M and OFF are valid. 1500 */ 1501 1502 /* check if we can safely examine src and dst ports */ 1503 if (m->m_pkthdr.len < off + sizeof *thp) 1504 return; 1505 1506 bzero(&th, sizeof th); 1507 m_copydata(m, off, sizeof *thp, (caddr_t)&th); 1508 1509 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport, 1510 (struct sockaddr *)ip6cp->ip6c_src, 1511 th.th_sport, cmd, arg, notify); 1512 1513 inc.inc_fport = th.th_dport; 1514 inc.inc_lport = th.th_sport; 1515 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr; 1516 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr; 1517 inc.inc_isipv6 = 1; 1518 syncache_unreach(&inc, &th); 1519 } else 1520 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0, 1521 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify); 1522 } 1523 #endif 1524 1525 /* 1526 * Following is where TCP initial sequence number generation occurs. 1527 * 1528 * There are two places where we must use initial sequence numbers: 1529 * 1. In SYN-ACK packets. 1530 * 2. In SYN packets. 1531 * 1532 * All ISNs for SYN-ACK packets are generated by the syncache. See 1533 * tcp_syncache.c for details. 1534 * 1535 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling 1536 * depends on this property. In addition, these ISNs should be 1537 * unguessable so as to prevent connection hijacking. To satisfy 1538 * the requirements of this situation, the algorithm outlined in 1539 * RFC 1948 is used to generate sequence numbers. 1540 * 1541 * Implementation details: 1542 * 1543 * Time is based off the system timer, and is corrected so that it 1544 * increases by one megabyte per second. This allows for proper 1545 * recycling on high speed LANs while still leaving over an hour 1546 * before rollover. 1547 * 1548 * net.inet.tcp.isn_reseed_interval controls the number of seconds 1549 * between seeding of isn_secret. This is normally set to zero, 1550 * as reseeding should not be necessary. 1551 * 1552 */ 1553 1554 #define ISN_BYTES_PER_SECOND 1048576 1555 1556 u_char isn_secret[32]; 1557 int isn_last_reseed; 1558 MD5_CTX isn_ctx; 1559 1560 tcp_seq 1561 tcp_new_isn(struct tcpcb *tp) 1562 { 1563 u_int32_t md5_buffer[4]; 1564 tcp_seq new_isn; 1565 1566 /* Seed if this is the first use, reseed if requested. */ 1567 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) && 1568 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) 1569 < (u_int)ticks))) { 1570 read_random_unlimited(&isn_secret, sizeof isn_secret); 1571 isn_last_reseed = ticks; 1572 } 1573 1574 /* Compute the md5 hash and return the ISN. */ 1575 MD5Init(&isn_ctx); 1576 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short)); 1577 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short)); 1578 #ifdef INET6 1579 if (tp->t_inpcb->inp_vflag & INP_IPV6) { 1580 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr, 1581 sizeof(struct in6_addr)); 1582 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr, 1583 sizeof(struct in6_addr)); 1584 } else 1585 #endif 1586 { 1587 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr, 1588 sizeof(struct in_addr)); 1589 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr, 1590 sizeof(struct in_addr)); 1591 } 1592 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret)); 1593 MD5Final((u_char *) &md5_buffer, &isn_ctx); 1594 new_isn = (tcp_seq) md5_buffer[0]; 1595 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz); 1596 return (new_isn); 1597 } 1598 1599 /* 1600 * When a source quench is received, close congestion window 1601 * to one segment. We will gradually open it again as we proceed. 1602 */ 1603 void 1604 tcp_quench(struct inpcb *inp, int error) 1605 { 1606 struct tcpcb *tp = intotcpcb(inp); 1607 1608 if (tp != NULL) { 1609 tp->snd_cwnd = tp->t_maxseg; 1610 tp->snd_wacked = 0; 1611 } 1612 } 1613 1614 /* 1615 * When a specific ICMP unreachable message is received and the 1616 * connection state is SYN-SENT, drop the connection. This behavior 1617 * is controlled by the icmp_may_rst sysctl. 1618 */ 1619 void 1620 tcp_drop_syn_sent(struct inpcb *inp, int error) 1621 { 1622 struct tcpcb *tp = intotcpcb(inp); 1623 1624 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT)) 1625 tcp_drop(tp, error); 1626 } 1627 1628 /* 1629 * When a `need fragmentation' ICMP is received, update our idea of the MSS 1630 * based on the new value in the route. Also nudge TCP to send something, 1631 * since we know the packet we just sent was dropped. 1632 * This duplicates some code in the tcp_mss() function in tcp_input.c. 1633 */ 1634 void 1635 tcp_mtudisc(struct inpcb *inp, int mtu) 1636 { 1637 struct tcpcb *tp = intotcpcb(inp); 1638 struct rtentry *rt; 1639 struct socket *so = inp->inp_socket; 1640 int maxopd, mss; 1641 #ifdef INET6 1642 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0); 1643 #else 1644 const boolean_t isipv6 = FALSE; 1645 #endif 1646 1647 if (tp == NULL) 1648 return; 1649 1650 /* 1651 * If no MTU is provided in the ICMP message, use the 1652 * next lower likely value, as specified in RFC 1191. 1653 */ 1654 if (mtu == 0) { 1655 int oldmtu; 1656 1657 oldmtu = tp->t_maxopd + 1658 (isipv6 ? 1659 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1660 sizeof(struct tcpiphdr)); 1661 mtu = ip_next_mtu(oldmtu, 0); 1662 } 1663 1664 if (isipv6) 1665 rt = tcp_rtlookup6(&inp->inp_inc); 1666 else 1667 rt = tcp_rtlookup(&inp->inp_inc); 1668 if (rt != NULL) { 1669 struct rmxp_tao *taop = rmx_taop(rt->rt_rmx); 1670 1671 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu) 1672 mtu = rt->rt_rmx.rmx_mtu; 1673 1674 maxopd = mtu - 1675 (isipv6 ? 1676 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1677 sizeof(struct tcpiphdr)); 1678 1679 /* 1680 * XXX - The following conditional probably violates the TCP 1681 * spec. The problem is that, since we don't know the 1682 * other end's MSS, we are supposed to use a conservative 1683 * default. But, if we do that, then MTU discovery will 1684 * never actually take place, because the conservative 1685 * default is much less than the MTUs typically seen 1686 * on the Internet today. For the moment, we'll sweep 1687 * this under the carpet. 1688 * 1689 * The conservative default might not actually be a problem 1690 * if the only case this occurs is when sending an initial 1691 * SYN with options and data to a host we've never talked 1692 * to before. Then, they will reply with an MSS value which 1693 * will get recorded and the new parameters should get 1694 * recomputed. For Further Study. 1695 */ 1696 if (taop->tao_mssopt != 0 && taop->tao_mssopt < maxopd) 1697 maxopd = taop->tao_mssopt; 1698 } else 1699 maxopd = mtu - 1700 (isipv6 ? 1701 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : 1702 sizeof(struct tcpiphdr)); 1703 1704 if (tp->t_maxopd <= maxopd) 1705 return; 1706 tp->t_maxopd = maxopd; 1707 1708 mss = maxopd; 1709 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) == 1710 (TF_REQ_TSTMP | TF_RCVD_TSTMP)) 1711 mss -= TCPOLEN_TSTAMP_APPA; 1712 1713 if ((tp->t_flags & (TF_REQ_CC | TF_RCVD_CC | TF_NOOPT)) == 1714 (TF_REQ_CC | TF_RCVD_CC)) 1715 mss -= TCPOLEN_CC_APPA; 1716 1717 /* round down to multiple of MCLBYTES */ 1718 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */ 1719 if (mss > MCLBYTES) 1720 mss &= ~(MCLBYTES - 1); 1721 #else 1722 if (mss > MCLBYTES) 1723 mss = (mss / MCLBYTES) * MCLBYTES; 1724 #endif 1725 1726 if (so->so_snd.ssb_hiwat < mss) 1727 mss = so->so_snd.ssb_hiwat; 1728 1729 tp->t_maxseg = mss; 1730 tp->t_rtttime = 0; 1731 tp->snd_nxt = tp->snd_una; 1732 tcp_output(tp); 1733 tcpstat.tcps_mturesent++; 1734 } 1735 1736 /* 1737 * Look-up the routing entry to the peer of this inpcb. If no route 1738 * is found and it cannot be allocated the return NULL. This routine 1739 * is called by TCP routines that access the rmx structure and by tcp_mss 1740 * to get the interface MTU. 1741 */ 1742 struct rtentry * 1743 tcp_rtlookup(struct in_conninfo *inc) 1744 { 1745 struct route *ro = &inc->inc_route; 1746 1747 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) { 1748 /* No route yet, so try to acquire one */ 1749 if (inc->inc_faddr.s_addr != INADDR_ANY) { 1750 /* 1751 * unused portions of the structure MUST be zero'd 1752 * out because rtalloc() treats it as opaque data 1753 */ 1754 bzero(&ro->ro_dst, sizeof(struct sockaddr_in)); 1755 ro->ro_dst.sa_family = AF_INET; 1756 ro->ro_dst.sa_len = sizeof(struct sockaddr_in); 1757 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 1758 inc->inc_faddr; 1759 rtalloc(ro); 1760 } 1761 } 1762 return (ro->ro_rt); 1763 } 1764 1765 #ifdef INET6 1766 struct rtentry * 1767 tcp_rtlookup6(struct in_conninfo *inc) 1768 { 1769 struct route_in6 *ro6 = &inc->inc6_route; 1770 1771 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) { 1772 /* No route yet, so try to acquire one */ 1773 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) { 1774 /* 1775 * unused portions of the structure MUST be zero'd 1776 * out because rtalloc() treats it as opaque data 1777 */ 1778 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6)); 1779 ro6->ro_dst.sin6_family = AF_INET6; 1780 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6); 1781 ro6->ro_dst.sin6_addr = inc->inc6_faddr; 1782 rtalloc((struct route *)ro6); 1783 } 1784 } 1785 return (ro6->ro_rt); 1786 } 1787 #endif 1788 1789 #ifdef IPSEC 1790 /* compute ESP/AH header size for TCP, including outer IP header. */ 1791 size_t 1792 ipsec_hdrsiz_tcp(struct tcpcb *tp) 1793 { 1794 struct inpcb *inp; 1795 struct mbuf *m; 1796 size_t hdrsiz; 1797 struct ip *ip; 1798 struct tcphdr *th; 1799 1800 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) 1801 return (0); 1802 MGETHDR(m, MB_DONTWAIT, MT_DATA); 1803 if (!m) 1804 return (0); 1805 1806 #ifdef INET6 1807 if (inp->inp_vflag & INP_IPV6) { 1808 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 1809 1810 th = (struct tcphdr *)(ip6 + 1); 1811 m->m_pkthdr.len = m->m_len = 1812 sizeof(struct ip6_hdr) + sizeof(struct tcphdr); 1813 tcp_fillheaders(tp, ip6, th); 1814 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1815 } else 1816 #endif 1817 { 1818 ip = mtod(m, struct ip *); 1819 th = (struct tcphdr *)(ip + 1); 1820 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr); 1821 tcp_fillheaders(tp, ip, th); 1822 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); 1823 } 1824 1825 m_free(m); 1826 return (hdrsiz); 1827 } 1828 #endif 1829 1830 /* 1831 * Return a pointer to the cached information about the remote host. 1832 * The cached information is stored in the protocol specific part of 1833 * the route metrics. 1834 */ 1835 struct rmxp_tao * 1836 tcp_gettaocache(struct in_conninfo *inc) 1837 { 1838 struct rtentry *rt; 1839 1840 #ifdef INET6 1841 if (inc->inc_isipv6) 1842 rt = tcp_rtlookup6(inc); 1843 else 1844 #endif 1845 rt = tcp_rtlookup(inc); 1846 1847 /* Make sure this is a host route and is up. */ 1848 if (rt == NULL || 1849 (rt->rt_flags & (RTF_UP | RTF_HOST)) != (RTF_UP | RTF_HOST)) 1850 return (NULL); 1851 1852 return (rmx_taop(rt->rt_rmx)); 1853 } 1854 1855 /* 1856 * Clear all the TAO cache entries, called from tcp_init. 1857 * 1858 * XXX 1859 * This routine is just an empty one, because we assume that the routing 1860 * routing tables are initialized at the same time when TCP, so there is 1861 * nothing in the cache left over. 1862 */ 1863 static void 1864 tcp_cleartaocache(void) 1865 { 1866 } 1867 1868 /* 1869 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING 1870 * 1871 * This code attempts to calculate the bandwidth-delay product as a 1872 * means of determining the optimal window size to maximize bandwidth, 1873 * minimize RTT, and avoid the over-allocation of buffers on interfaces and 1874 * routers. This code also does a fairly good job keeping RTTs in check 1875 * across slow links like modems. We implement an algorithm which is very 1876 * similar (but not meant to be) TCP/Vegas. The code operates on the 1877 * transmitter side of a TCP connection and so only effects the transmit 1878 * side of the connection. 1879 * 1880 * BACKGROUND: TCP makes no provision for the management of buffer space 1881 * at the end points or at the intermediate routers and switches. A TCP 1882 * stream, whether using NewReno or not, will eventually buffer as 1883 * many packets as it is able and the only reason this typically works is 1884 * due to the fairly small default buffers made available for a connection 1885 * (typicaly 16K or 32K). As machines use larger windows and/or window 1886 * scaling it is now fairly easy for even a single TCP connection to blow-out 1887 * all available buffer space not only on the local interface, but on 1888 * intermediate routers and switches as well. NewReno makes a misguided 1889 * attempt to 'solve' this problem by waiting for an actual failure to occur, 1890 * then backing off, then steadily increasing the window again until another 1891 * failure occurs, ad-infinitum. This results in terrible oscillation that 1892 * is only made worse as network loads increase and the idea of intentionally 1893 * blowing out network buffers is, frankly, a terrible way to manage network 1894 * resources. 1895 * 1896 * It is far better to limit the transmit window prior to the failure 1897 * condition being achieved. There are two general ways to do this: First 1898 * you can 'scan' through different transmit window sizes and locate the 1899 * point where the RTT stops increasing, indicating that you have filled the 1900 * pipe, then scan backwards until you note that RTT stops decreasing, then 1901 * repeat ad-infinitum. This method works in principle but has severe 1902 * implementation issues due to RTT variances, timer granularity, and 1903 * instability in the algorithm which can lead to many false positives and 1904 * create oscillations as well as interact badly with other TCP streams 1905 * implementing the same algorithm. 1906 * 1907 * The second method is to limit the window to the bandwidth delay product 1908 * of the link. This is the method we implement. RTT variances and our 1909 * own manipulation of the congestion window, bwnd, can potentially 1910 * destabilize the algorithm. For this reason we have to stabilize the 1911 * elements used to calculate the window. We do this by using the minimum 1912 * observed RTT, the long term average of the observed bandwidth, and 1913 * by adding two segments worth of slop. It isn't perfect but it is able 1914 * to react to changing conditions and gives us a very stable basis on 1915 * which to extend the algorithm. 1916 */ 1917 void 1918 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq) 1919 { 1920 u_long bw; 1921 u_long bwnd; 1922 int save_ticks; 1923 int delta_ticks; 1924 1925 /* 1926 * If inflight_enable is disabled in the middle of a tcp connection, 1927 * make sure snd_bwnd is effectively disabled. 1928 */ 1929 if (!tcp_inflight_enable) { 1930 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 1931 tp->snd_bandwidth = 0; 1932 return; 1933 } 1934 1935 /* 1936 * Validate the delta time. If a connection is new or has been idle 1937 * a long time we have to reset the bandwidth calculator. 1938 */ 1939 save_ticks = ticks; 1940 delta_ticks = save_ticks - tp->t_bw_rtttime; 1941 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) { 1942 tp->t_bw_rtttime = ticks; 1943 tp->t_bw_rtseq = ack_seq; 1944 if (tp->snd_bandwidth == 0) 1945 tp->snd_bandwidth = tcp_inflight_min; 1946 return; 1947 } 1948 if (delta_ticks == 0) 1949 return; 1950 1951 /* 1952 * Sanity check, plus ignore pure window update acks. 1953 */ 1954 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0) 1955 return; 1956 1957 /* 1958 * Figure out the bandwidth. Due to the tick granularity this 1959 * is a very rough number and it MUST be averaged over a fairly 1960 * long period of time. XXX we need to take into account a link 1961 * that is not using all available bandwidth, but for now our 1962 * slop will ramp us up if this case occurs and the bandwidth later 1963 * increases. 1964 */ 1965 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks; 1966 tp->t_bw_rtttime = save_ticks; 1967 tp->t_bw_rtseq = ack_seq; 1968 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4; 1969 1970 tp->snd_bandwidth = bw; 1971 1972 /* 1973 * Calculate the semi-static bandwidth delay product, plus two maximal 1974 * segments. The additional slop puts us squarely in the sweet 1975 * spot and also handles the bandwidth run-up case. Without the 1976 * slop we could be locking ourselves into a lower bandwidth. 1977 * 1978 * Situations Handled: 1979 * (1) Prevents over-queueing of packets on LANs, especially on 1980 * high speed LANs, allowing larger TCP buffers to be 1981 * specified, and also does a good job preventing 1982 * over-queueing of packets over choke points like modems 1983 * (at least for the transmit side). 1984 * 1985 * (2) Is able to handle changing network loads (bandwidth 1986 * drops so bwnd drops, bandwidth increases so bwnd 1987 * increases). 1988 * 1989 * (3) Theoretically should stabilize in the face of multiple 1990 * connections implementing the same algorithm (this may need 1991 * a little work). 1992 * 1993 * (4) Stability value (defaults to 20 = 2 maximal packets) can 1994 * be adjusted with a sysctl but typically only needs to be on 1995 * very slow connections. A value no smaller then 5 should 1996 * be used, but only reduce this default if you have no other 1997 * choice. 1998 */ 1999 2000 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2) 2001 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + 2002 tcp_inflight_stab * (int)tp->t_maxseg / 10; 2003 #undef USERTT 2004 2005 if (tcp_inflight_debug > 0) { 2006 static int ltime; 2007 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) { 2008 ltime = ticks; 2009 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n", 2010 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd); 2011 } 2012 } 2013 if ((long)bwnd < tcp_inflight_min) 2014 bwnd = tcp_inflight_min; 2015 if (bwnd > tcp_inflight_max) 2016 bwnd = tcp_inflight_max; 2017 if ((long)bwnd < tp->t_maxseg * 2) 2018 bwnd = tp->t_maxseg * 2; 2019 tp->snd_bwnd = bwnd; 2020 } 2021