1 /* 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 34 * $FreeBSD$ 35 */ 36 37 #include "opt_compat.h" 38 #include "opt_inet6.h" 39 #include "opt_tcpdebug.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/callout.h> 44 #include <sys/kernel.h> 45 #include <sys/sysctl.h> 46 #include <sys/malloc.h> 47 #include <sys/mbuf.h> 48 #include <sys/proc.h> 49 #include <sys/socket.h> 50 #include <sys/socketvar.h> 51 #include <sys/protosw.h> 52 53 #include <vm/vm_zone.h> 54 55 #include <net/route.h> 56 #include <net/if.h> 57 58 #define _IP_VHL 59 #include <netinet/in.h> 60 #include <netinet/in_systm.h> 61 #include <netinet/ip.h> 62 #include <netinet/in_pcb.h> 63 #include <netinet/in_var.h> 64 #include <netinet/ip_var.h> 65 #include <netinet/tcp.h> 66 #include <netinet/tcp_fsm.h> 67 #include <netinet/tcp_seq.h> 68 #include <netinet/tcp_timer.h> 69 #include <netinet/tcp_var.h> 70 #include <netinet/tcpip.h> 71 #ifdef TCPDEBUG 72 #include <netinet/tcp_debug.h> 73 #endif 74 75 int tcp_mssdflt = TCP_MSS; 76 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 77 &tcp_mssdflt , 0, "Default TCP Maximum Segment Size"); 78 79 #ifdef INET6 80 int tcp_v6mssdflt = TCP6_MSS; 81 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, 82 CTLFLAG_RW, &tcp_v6mssdflt , 0, ""); 83 #endif 84 85 #if 0 86 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 87 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 88 &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time"); 89 #endif 90 91 static int tcp_do_rfc1323 = 1; 92 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 93 &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions"); 94 95 static int tcp_do_rfc1644 = 0; 96 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 97 &tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions"); 98 99 static int tcp_tcbhashsize = 0; 100 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, 101 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); 102 103 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 104 &tcbinfo.ipi_count, 0, "Number of active PCBs"); 105 106 static void tcp_cleartaocache __P((void)); 107 static void tcp_notify __P((struct inpcb *, int)); 108 109 /* 110 * Target size of TCP PCB hash tables. Must be a power of two. 111 * 112 * Note that this can be overridden by the kernel environment 113 * variable net.inet.tcp.tcbhashsize 114 */ 115 #ifndef TCBHASHSIZE 116 #define TCBHASHSIZE 512 117 #endif 118 119 /* 120 * This is the actual shape of what we allocate using the zone 121 * allocator. Doing it this way allows us to protect both structures 122 * using the same generation count, and also eliminates the overhead 123 * of allocating tcpcbs separately. By hiding the structure here, 124 * we avoid changing most of the rest of the code (although it needs 125 * to be changed, eventually, for greater efficiency). 126 */ 127 #define ALIGNMENT 32 128 #define ALIGNM1 (ALIGNMENT - 1) 129 struct inp_tp { 130 union { 131 struct inpcb inp; 132 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 133 } inp_tp_u; 134 struct tcpcb tcb; 135 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl; 136 struct callout inp_tp_delack; 137 }; 138 #undef ALIGNMENT 139 #undef ALIGNM1 140 141 /* 142 * Tcp initialization 143 */ 144 void 145 tcp_init() 146 { 147 int hashsize; 148 149 tcp_iss = random(); /* wrong, but better than a constant */ 150 tcp_ccgen = 1; 151 tcp_cleartaocache(); 152 153 tcp_delacktime = TCPTV_DELACK; 154 tcp_keepinit = TCPTV_KEEP_INIT; 155 tcp_keepidle = TCPTV_KEEP_IDLE; 156 tcp_keepintvl = TCPTV_KEEPINTVL; 157 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 158 tcp_msl = TCPTV_MSL; 159 160 LIST_INIT(&tcb); 161 tcbinfo.listhead = &tcb; 162 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", TCBHASHSIZE, hashsize); 163 if (!powerof2(hashsize)) { 164 printf("WARNING: TCB hash size not a power of 2\n"); 165 hashsize = 512; /* safe default */ 166 } 167 tcp_tcbhashsize = hashsize; 168 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask); 169 tcbinfo.porthashbase = hashinit(hashsize, M_PCB, 170 &tcbinfo.porthashmask); 171 tcbinfo.ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 172 ZONE_INTERRUPT, 0); 173 174 if (max_protohdr < sizeof(struct tcpiphdr)) 175 max_protohdr = sizeof(struct tcpiphdr); 176 if (max_linkhdr + sizeof(struct tcpiphdr) > MHLEN) 177 panic("tcp_init"); 178 } 179 180 /* 181 * Create template to be used to send tcp packets on a connection. 182 * Call after host entry created, allocates an mbuf and fills 183 * in a skeletal tcp/ip header, minimizing the amount of work 184 * necessary when the connection is used. 185 */ 186 struct tcpiphdr * 187 tcp_template(tp) 188 struct tcpcb *tp; 189 { 190 register struct inpcb *inp = tp->t_inpcb; 191 register struct mbuf *m; 192 register struct tcpiphdr *n; 193 194 if ((n = tp->t_template) == 0) { 195 m = m_get(M_DONTWAIT, MT_HEADER); 196 if (m == NULL) 197 return (0); 198 m->m_len = sizeof (struct tcpiphdr); 199 n = mtod(m, struct tcpiphdr *); 200 } 201 bzero(n->ti_x1, sizeof(n->ti_x1)); 202 n->ti_pr = IPPROTO_TCP; 203 n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip)); 204 n->ti_src = inp->inp_laddr; 205 n->ti_dst = inp->inp_faddr; 206 n->ti_sport = inp->inp_lport; 207 n->ti_dport = inp->inp_fport; 208 n->ti_seq = 0; 209 n->ti_ack = 0; 210 n->ti_x2 = 0; 211 n->ti_off = 5; 212 n->ti_flags = 0; 213 n->ti_win = 0; 214 n->ti_sum = 0; 215 n->ti_urp = 0; 216 return (n); 217 } 218 219 /* 220 * Send a single message to the TCP at address specified by 221 * the given TCP/IP header. If m == 0, then we make a copy 222 * of the tcpiphdr at ti and send directly to the addressed host. 223 * This is used to force keep alive messages out using the TCP 224 * template for a connection tp->t_template. If flags are given 225 * then we send a message back to the TCP which originated the 226 * segment ti, and discard the mbuf containing it and any other 227 * attached mbufs. 228 * 229 * In any case the ack and sequence number of the transmitted 230 * segment are as specified by the parameters. 231 * 232 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 233 */ 234 void 235 tcp_respond(tp, ti, m, ack, seq, flags) 236 struct tcpcb *tp; 237 register struct tcpiphdr *ti; 238 register struct mbuf *m; 239 tcp_seq ack, seq; 240 int flags; 241 { 242 register int tlen; 243 int win = 0; 244 struct route *ro = 0; 245 struct route sro; 246 247 if (tp) { 248 if (!(flags & TH_RST)) 249 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 250 ro = &tp->t_inpcb->inp_route; 251 } else { 252 ro = &sro; 253 bzero(ro, sizeof *ro); 254 } 255 if (m == 0) { 256 m = m_gethdr(M_DONTWAIT, MT_HEADER); 257 if (m == NULL) 258 return; 259 #ifdef TCP_COMPAT_42 260 tlen = 1; 261 #else 262 tlen = 0; 263 #endif 264 m->m_data += max_linkhdr; 265 *mtod(m, struct tcpiphdr *) = *ti; 266 ti = mtod(m, struct tcpiphdr *); 267 flags = TH_ACK; 268 } else { 269 m_freem(m->m_next); 270 m->m_next = 0; 271 m->m_data = (caddr_t)ti; 272 m->m_len = sizeof (struct tcpiphdr); 273 tlen = 0; 274 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 275 xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, n_long); 276 xchg(ti->ti_dport, ti->ti_sport, n_short); 277 #undef xchg 278 } 279 ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen)); 280 tlen += sizeof (struct tcpiphdr); 281 m->m_len = tlen; 282 m->m_pkthdr.len = tlen; 283 m->m_pkthdr.rcvif = (struct ifnet *) 0; 284 bzero(ti->ti_x1, sizeof(ti->ti_x1)); 285 ti->ti_seq = htonl(seq); 286 ti->ti_ack = htonl(ack); 287 ti->ti_x2 = 0; 288 ti->ti_off = sizeof (struct tcphdr) >> 2; 289 ti->ti_flags = flags; 290 if (tp) 291 ti->ti_win = htons((u_short) (win >> tp->rcv_scale)); 292 else 293 ti->ti_win = htons((u_short)win); 294 ti->ti_urp = 0; 295 ti->ti_sum = 0; 296 ti->ti_sum = in_cksum(m, tlen); 297 ((struct ip *)ti)->ip_len = tlen; 298 ((struct ip *)ti)->ip_ttl = ip_defttl; 299 #ifdef TCPDEBUG 300 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 301 tcp_trace(TA_OUTPUT, 0, tp, ti, 0); 302 #endif 303 (void) ip_output(m, NULL, ro, 0, NULL); 304 if (ro == &sro && ro->ro_rt) { 305 RTFREE(ro->ro_rt); 306 } 307 } 308 309 /* 310 * Create a new TCP control block, making an 311 * empty reassembly queue and hooking it to the argument 312 * protocol control block. The `inp' parameter must have 313 * come from the zone allocator set up in tcp_init(). 314 */ 315 struct tcpcb * 316 tcp_newtcpcb(inp) 317 struct inpcb *inp; 318 { 319 struct inp_tp *it; 320 register struct tcpcb *tp; 321 322 it = (struct inp_tp *)inp; 323 tp = &it->tcb; 324 bzero((char *) tp, sizeof(struct tcpcb)); 325 tp->t_segq = NULL; 326 tp->t_maxseg = tp->t_maxopd = tcp_mssdflt; 327 328 /* Set up our timeouts. */ 329 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt); 330 callout_init(tp->tt_persist = &it->inp_tp_persist); 331 callout_init(tp->tt_keep = &it->inp_tp_keep); 332 callout_init(tp->tt_2msl = &it->inp_tp_2msl); 333 callout_init(tp->tt_delack = &it->inp_tp_delack); 334 335 if (tcp_do_rfc1323) 336 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 337 if (tcp_do_rfc1644) 338 tp->t_flags |= TF_REQ_CC; 339 tp->t_inpcb = inp; /* XXX */ 340 /* 341 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 342 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 343 * reasonable initial retransmit time. 344 */ 345 tp->t_srtt = TCPTV_SRTTBASE; 346 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 347 tp->t_rttmin = TCPTV_MIN; 348 tp->t_rxtcur = TCPTV_RTOBASE; 349 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 350 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 351 tp->t_rcvtime = ticks; 352 inp->inp_ip_ttl = ip_defttl; 353 inp->inp_ppcb = (caddr_t)tp; 354 return (tp); /* XXX */ 355 } 356 357 /* 358 * Drop a TCP connection, reporting 359 * the specified error. If connection is synchronized, 360 * then send a RST to peer. 361 */ 362 struct tcpcb * 363 tcp_drop(tp, errno) 364 register struct tcpcb *tp; 365 int errno; 366 { 367 struct socket *so = tp->t_inpcb->inp_socket; 368 369 if (TCPS_HAVERCVDSYN(tp->t_state)) { 370 tp->t_state = TCPS_CLOSED; 371 (void) tcp_output(tp); 372 tcpstat.tcps_drops++; 373 } else 374 tcpstat.tcps_conndrops++; 375 if (errno == ETIMEDOUT && tp->t_softerror) 376 errno = tp->t_softerror; 377 so->so_error = errno; 378 return (tcp_close(tp)); 379 } 380 381 /* 382 * Close a TCP control block: 383 * discard all space held by the tcp 384 * discard internet protocol block 385 * wake up any sleepers 386 */ 387 struct tcpcb * 388 tcp_close(tp) 389 register struct tcpcb *tp; 390 { 391 register struct mbuf *q; 392 register struct mbuf *nq; 393 struct inpcb *inp = tp->t_inpcb; 394 struct socket *so = inp->inp_socket; 395 register struct rtentry *rt; 396 int dosavessthresh; 397 398 /* 399 * Make sure that all of our timers are stopped before we 400 * delete the PCB. 401 */ 402 callout_stop(tp->tt_rexmt); 403 callout_stop(tp->tt_persist); 404 callout_stop(tp->tt_keep); 405 callout_stop(tp->tt_2msl); 406 callout_stop(tp->tt_delack); 407 408 /* 409 * If we got enough samples through the srtt filter, 410 * save the rtt and rttvar in the routing entry. 411 * 'Enough' is arbitrarily defined as the 16 samples. 412 * 16 samples is enough for the srtt filter to converge 413 * to within 5% of the correct value; fewer samples and 414 * we could save a very bogus rtt. 415 * 416 * Don't update the default route's characteristics and don't 417 * update anything that the user "locked". 418 */ 419 if (tp->t_rttupdated >= 16 && 420 (rt = inp->inp_route.ro_rt) && 421 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr != INADDR_ANY) { 422 register u_long i = 0; 423 424 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 425 i = tp->t_srtt * 426 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE)); 427 if (rt->rt_rmx.rmx_rtt && i) 428 /* 429 * filter this update to half the old & half 430 * the new values, converting scale. 431 * See route.h and tcp_var.h for a 432 * description of the scaling constants. 433 */ 434 rt->rt_rmx.rmx_rtt = 435 (rt->rt_rmx.rmx_rtt + i) / 2; 436 else 437 rt->rt_rmx.rmx_rtt = i; 438 tcpstat.tcps_cachedrtt++; 439 } 440 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 441 i = tp->t_rttvar * 442 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE)); 443 if (rt->rt_rmx.rmx_rttvar && i) 444 rt->rt_rmx.rmx_rttvar = 445 (rt->rt_rmx.rmx_rttvar + i) / 2; 446 else 447 rt->rt_rmx.rmx_rttvar = i; 448 tcpstat.tcps_cachedrttvar++; 449 } 450 /* 451 * The old comment here said: 452 * update the pipelimit (ssthresh) if it has been updated 453 * already or if a pipesize was specified & the threshhold 454 * got below half the pipesize. I.e., wait for bad news 455 * before we start updating, then update on both good 456 * and bad news. 457 * 458 * But we want to save the ssthresh even if no pipesize is 459 * specified explicitly in the route, because such 460 * connections still have an implicit pipesize specified 461 * by the global tcp_sendspace. In the absence of a reliable 462 * way to calculate the pipesize, it will have to do. 463 */ 464 i = tp->snd_ssthresh; 465 if (rt->rt_rmx.rmx_sendpipe != 0) 466 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2); 467 else 468 dosavessthresh = (i < so->so_snd.sb_hiwat / 2); 469 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 470 i != 0 && rt->rt_rmx.rmx_ssthresh != 0) 471 || dosavessthresh) { 472 /* 473 * convert the limit from user data bytes to 474 * packets then to packet data bytes. 475 */ 476 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 477 if (i < 2) 478 i = 2; 479 i *= (u_long)(tp->t_maxseg + sizeof (struct tcpiphdr)); 480 if (rt->rt_rmx.rmx_ssthresh) 481 rt->rt_rmx.rmx_ssthresh = 482 (rt->rt_rmx.rmx_ssthresh + i) / 2; 483 else 484 rt->rt_rmx.rmx_ssthresh = i; 485 tcpstat.tcps_cachedssthresh++; 486 } 487 } 488 /* free the reassembly queue, if any */ 489 for (q = tp->t_segq; q; q = nq) { 490 nq = q->m_nextpkt; 491 tp->t_segq = nq; 492 m_freem(q); 493 } 494 if (tp->t_template) 495 (void) m_free(dtom(tp->t_template)); 496 inp->inp_ppcb = NULL; 497 soisdisconnected(so); 498 in_pcbdetach(inp); 499 tcpstat.tcps_closed++; 500 return ((struct tcpcb *)0); 501 } 502 503 void 504 tcp_drain() 505 { 506 507 } 508 509 /* 510 * Notify a tcp user of an asynchronous error; 511 * store error as soft error, but wake up user 512 * (for now, won't do anything until can select for soft error). 513 */ 514 static void 515 tcp_notify(inp, error) 516 struct inpcb *inp; 517 int error; 518 { 519 register struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 520 register struct socket *so = inp->inp_socket; 521 522 /* 523 * Ignore some errors if we are hooked up. 524 * If connection hasn't completed, has retransmitted several times, 525 * and receives a second error, give up now. This is better 526 * than waiting a long time to establish a connection that 527 * can never complete. 528 */ 529 if (tp->t_state == TCPS_ESTABLISHED && 530 (error == EHOSTUNREACH || error == ENETUNREACH || 531 error == EHOSTDOWN)) { 532 return; 533 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 534 tp->t_softerror) 535 so->so_error = error; 536 else 537 tp->t_softerror = error; 538 wakeup((caddr_t) &so->so_timeo); 539 sorwakeup(so); 540 sowwakeup(so); 541 } 542 543 static int 544 tcp_pcblist SYSCTL_HANDLER_ARGS 545 { 546 int error, i, n, s; 547 struct inpcb *inp, **inp_list; 548 inp_gen_t gencnt; 549 struct xinpgen xig; 550 551 /* 552 * The process of preparing the TCB list is too time-consuming and 553 * resource-intensive to repeat twice on every request. 554 */ 555 if (req->oldptr == 0) { 556 n = tcbinfo.ipi_count; 557 req->oldidx = 2 * (sizeof xig) 558 + (n + n/8) * sizeof(struct xtcpcb); 559 return 0; 560 } 561 562 if (req->newptr != 0) 563 return EPERM; 564 565 /* 566 * OK, now we're committed to doing something. 567 */ 568 s = splnet(); 569 gencnt = tcbinfo.ipi_gencnt; 570 n = tcbinfo.ipi_count; 571 splx(s); 572 573 xig.xig_len = sizeof xig; 574 xig.xig_count = n; 575 xig.xig_gen = gencnt; 576 xig.xig_sogen = so_gencnt; 577 error = SYSCTL_OUT(req, &xig, sizeof xig); 578 if (error) 579 return error; 580 581 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 582 if (inp_list == 0) 583 return ENOMEM; 584 585 s = splnet(); 586 for (inp = tcbinfo.listhead->lh_first, i = 0; inp && i < n; 587 inp = inp->inp_list.le_next) { 588 if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->p, inp)) 589 inp_list[i++] = inp; 590 } 591 splx(s); 592 n = i; 593 594 error = 0; 595 for (i = 0; i < n; i++) { 596 inp = inp_list[i]; 597 if (inp->inp_gencnt <= gencnt) { 598 struct xtcpcb xt; 599 caddr_t inp_ppcb; 600 xt.xt_len = sizeof xt; 601 /* XXX should avoid extra copy */ 602 bcopy(inp, &xt.xt_inp, sizeof *inp); 603 inp_ppcb = inp->inp_ppcb; 604 if (inp_ppcb != NULL) 605 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 606 else 607 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 608 if (inp->inp_socket) 609 sotoxsocket(inp->inp_socket, &xt.xt_socket); 610 error = SYSCTL_OUT(req, &xt, sizeof xt); 611 } 612 } 613 if (!error) { 614 /* 615 * Give the user an updated idea of our state. 616 * If the generation differs from what we told 617 * her before, she knows that something happened 618 * while we were processing this request, and it 619 * might be necessary to retry. 620 */ 621 s = splnet(); 622 xig.xig_gen = tcbinfo.ipi_gencnt; 623 xig.xig_sogen = so_gencnt; 624 xig.xig_count = tcbinfo.ipi_count; 625 splx(s); 626 error = SYSCTL_OUT(req, &xig, sizeof xig); 627 } 628 free(inp_list, M_TEMP); 629 return error; 630 } 631 632 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 633 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 634 635 static int 636 tcp_getcred SYSCTL_HANDLER_ARGS 637 { 638 struct sockaddr_in addrs[2]; 639 struct inpcb *inp; 640 int error, s; 641 642 error = suser(req->p); 643 if (error) 644 return (error); 645 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 646 if (error) 647 return (error); 648 s = splnet(); 649 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 650 addrs[0].sin_addr, addrs[0].sin_port, 0, NULL); 651 if (inp == NULL || inp->inp_socket == NULL) { 652 error = ENOENT; 653 goto out; 654 } 655 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred)); 656 out: 657 splx(s); 658 return (error); 659 } 660 661 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 662 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 663 664 void 665 tcp_ctlinput(cmd, sa, vip) 666 int cmd; 667 struct sockaddr *sa; 668 void *vip; 669 { 670 register struct ip *ip = vip; 671 register struct tcphdr *th; 672 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 673 674 if (cmd == PRC_QUENCH) 675 notify = tcp_quench; 676 else if (cmd == PRC_MSGSIZE) 677 notify = tcp_mtudisc; 678 else if (!PRC_IS_REDIRECT(cmd) && 679 ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0)) 680 return; 681 if (ip) { 682 th = (struct tcphdr *)((caddr_t)ip 683 + (IP_VHL_HL(ip->ip_vhl) << 2)); 684 in_pcbnotify(&tcb, sa, th->th_dport, ip->ip_src, th->th_sport, 685 cmd, notify); 686 } else 687 in_pcbnotify(&tcb, sa, 0, zeroin_addr, 0, cmd, notify); 688 } 689 690 /* 691 * When a source quench is received, close congestion window 692 * to one segment. We will gradually open it again as we proceed. 693 */ 694 void 695 tcp_quench(inp, errno) 696 struct inpcb *inp; 697 int errno; 698 { 699 struct tcpcb *tp = intotcpcb(inp); 700 701 if (tp) 702 tp->snd_cwnd = tp->t_maxseg; 703 } 704 705 /* 706 * When `need fragmentation' ICMP is received, update our idea of the MSS 707 * based on the new value in the route. Also nudge TCP to send something, 708 * since we know the packet we just sent was dropped. 709 * This duplicates some code in the tcp_mss() function in tcp_input.c. 710 */ 711 void 712 tcp_mtudisc(inp, errno) 713 struct inpcb *inp; 714 int errno; 715 { 716 struct tcpcb *tp = intotcpcb(inp); 717 struct rtentry *rt; 718 struct rmxp_tao *taop; 719 struct socket *so = inp->inp_socket; 720 int offered; 721 int mss; 722 723 if (tp) { 724 rt = tcp_rtlookup(inp); 725 if (!rt || !rt->rt_rmx.rmx_mtu) { 726 tp->t_maxopd = tp->t_maxseg = tcp_mssdflt; 727 return; 728 } 729 taop = rmx_taop(rt->rt_rmx); 730 offered = taop->tao_mssopt; 731 mss = rt->rt_rmx.rmx_mtu - sizeof(struct tcpiphdr); 732 if (offered) 733 mss = min(mss, offered); 734 /* 735 * XXX - The above conditional probably violates the TCP 736 * spec. The problem is that, since we don't know the 737 * other end's MSS, we are supposed to use a conservative 738 * default. But, if we do that, then MTU discovery will 739 * never actually take place, because the conservative 740 * default is much less than the MTUs typically seen 741 * on the Internet today. For the moment, we'll sweep 742 * this under the carpet. 743 * 744 * The conservative default might not actually be a problem 745 * if the only case this occurs is when sending an initial 746 * SYN with options and data to a host we've never talked 747 * to before. Then, they will reply with an MSS value which 748 * will get recorded and the new parameters should get 749 * recomputed. For Further Study. 750 */ 751 if (tp->t_maxopd <= mss) 752 return; 753 tp->t_maxopd = mss; 754 755 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 756 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 757 mss -= TCPOLEN_TSTAMP_APPA; 758 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC && 759 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC) 760 mss -= TCPOLEN_CC_APPA; 761 #if (MCLBYTES & (MCLBYTES - 1)) == 0 762 if (mss > MCLBYTES) 763 mss &= ~(MCLBYTES-1); 764 #else 765 if (mss > MCLBYTES) 766 mss = mss / MCLBYTES * MCLBYTES; 767 #endif 768 if (so->so_snd.sb_hiwat < mss) 769 mss = so->so_snd.sb_hiwat; 770 771 tp->t_maxseg = mss; 772 773 tcpstat.tcps_mturesent++; 774 tp->t_rtttime = 0; 775 tp->snd_nxt = tp->snd_una; 776 tcp_output(tp); 777 } 778 } 779 780 /* 781 * Look-up the routing entry to the peer of this inpcb. If no route 782 * is found and it cannot be allocated the return NULL. This routine 783 * is called by TCP routines that access the rmx structure and by tcp_mss 784 * to get the interface MTU. 785 */ 786 struct rtentry * 787 tcp_rtlookup(inp) 788 struct inpcb *inp; 789 { 790 struct route *ro; 791 struct rtentry *rt; 792 793 ro = &inp->inp_route; 794 rt = ro->ro_rt; 795 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 796 /* No route yet, so try to acquire one */ 797 if (inp->inp_faddr.s_addr != INADDR_ANY) { 798 ro->ro_dst.sa_family = AF_INET; 799 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 800 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 801 inp->inp_faddr; 802 rtalloc(ro); 803 rt = ro->ro_rt; 804 } 805 } 806 return rt; 807 } 808 809 /* 810 * Return a pointer to the cached information about the remote host. 811 * The cached information is stored in the protocol specific part of 812 * the route metrics. 813 */ 814 struct rmxp_tao * 815 tcp_gettaocache(inp) 816 struct inpcb *inp; 817 { 818 struct rtentry *rt = tcp_rtlookup(inp); 819 820 /* Make sure this is a host route and is up. */ 821 if (rt == NULL || 822 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)) 823 return NULL; 824 825 return rmx_taop(rt->rt_rmx); 826 } 827 828 /* 829 * Clear all the TAO cache entries, called from tcp_init. 830 * 831 * XXX 832 * This routine is just an empty one, because we assume that the routing 833 * routing tables are initialized at the same time when TCP, so there is 834 * nothing in the cache left over. 835 */ 836 static void 837 tcp_cleartaocache() 838 { 839 } 840