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