Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet/tcp_subr.c
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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/kernel.h> 43 #include <sys/sysctl.h> 44 #include <sys/malloc.h> 45 #include <sys/mbuf.h> 46 #include <sys/proc.h> 47 #include <sys/socket.h> 48 #include <sys/socketvar.h> 49 #include <sys/protosw.h> 50 #include <vm/vm_zone.h> 51 52 #include <i386/include/random.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, 76 CTLFLAG_RW, &tcp_mssdflt , 0, ""); 77 78 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; 79 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, 80 CTLFLAG_RW, &tcp_rttdflt , 0, ""); 81 82 static int tcp_do_rfc1323 = 1; 83 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, 84 CTLFLAG_RW, &tcp_do_rfc1323 , 0, ""); 85 86 static int tcp_do_rfc1644 = 0; 87 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, 88 CTLFLAG_RW, &tcp_do_rfc1644 , 0, ""); 89 90 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, &tcbinfo.ipi_count, 91 0, "Number of active PCBs"); 92 93 static void tcp_cleartaocache __P((void)); 94 static void tcp_notify __P((struct inpcb *, int)); 95 96 /* 97 * Target size of TCP PCB hash tables. Must be a power of two. 98 * 99 * Note that this can be overridden by the kernel environment 100 * variable net.inet.tcp.tcbhashsize 101 */ 102 #ifndef TCBHASHSIZE 103 #define TCBHASHSIZE 512 104 #endif 105 106 /* 107 * This is the actual shape of what we allocate using the zone 108 * allocator. Doing it this way allows us to protect both structures 109 * using the same generation count, and also eliminates the overhead 110 * of allocating tcpcbs separately. By hiding the structure here, 111 * we avoid changing most of the rest of the code (although it needs 112 * to be changed, eventually, for greater efficiency). 113 */ 114 #define ALIGNMENT 32 115 #define ALIGNM1 (ALIGNMENT - 1) 116 struct inp_tp { 117 union { 118 struct inpcb inp; 119 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; 120 } inp_tp_u; 121 struct tcpcb tcb; 122 }; 123 #undef ALIGNMENT 124 #undef ALIGNM1 125 126 /* 127 * Tcp initialization 128 */ 129 void 130 tcp_init() 131 { 132 int hashsize; 133 134 #ifdef TCP_COMPAT_42 135 tcp_iss = 1; /* wrong */ 136 #endif /* TCP_COMPAT_42 */ 137 tcp_ccgen = 1; 138 tcp_cleartaocache(); 139 LIST_INIT(&tcb); 140 tcbinfo.listhead = &tcb; 141 if (!(getenv_int("net.inet.tcp.tcbhashsize", &hashsize))) 142 hashsize = TCBHASHSIZE; 143 if (!powerof2(hashsize)) { 144 printf("WARNING: TCB hash size not a power of 2\n"); 145 hashsize = 512; /* safe default */ 146 } 147 tcbinfo.hashbase = hashinit(hashsize, M_PCB, &tcbinfo.hashmask); 148 tcbinfo.porthashbase = hashinit(hashsize, M_PCB, 149 &tcbinfo.porthashmask); 150 tcbinfo.ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets, 151 ZONE_INTERRUPT, 0); 152 if (max_protohdr < sizeof(struct tcpiphdr)) 153 max_protohdr = sizeof(struct tcpiphdr); 154 if (max_linkhdr + sizeof(struct tcpiphdr) > MHLEN) 155 panic("tcp_init"); 156 } 157 158 /* 159 * Create template to be used to send tcp packets on a connection. 160 * Call after host entry created, allocates an mbuf and fills 161 * in a skeletal tcp/ip header, minimizing the amount of work 162 * necessary when the connection is used. 163 */ 164 struct tcpiphdr * 165 tcp_template(tp) 166 struct tcpcb *tp; 167 { 168 register struct inpcb *inp = tp->t_inpcb; 169 register struct mbuf *m; 170 register struct tcpiphdr *n; 171 172 if ((n = tp->t_template) == 0) { 173 m = m_get(M_DONTWAIT, MT_HEADER); 174 if (m == NULL) 175 return (0); 176 m->m_len = sizeof (struct tcpiphdr); 177 n = mtod(m, struct tcpiphdr *); 178 } 179 bzero(n->ti_x1, sizeof(n->ti_x1)); 180 n->ti_pr = IPPROTO_TCP; 181 n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip)); 182 n->ti_src = inp->inp_laddr; 183 n->ti_dst = inp->inp_faddr; 184 n->ti_sport = inp->inp_lport; 185 n->ti_dport = inp->inp_fport; 186 n->ti_seq = 0; 187 n->ti_ack = 0; 188 n->ti_x2 = 0; 189 n->ti_off = 5; 190 n->ti_flags = 0; 191 n->ti_win = 0; 192 n->ti_sum = 0; 193 n->ti_urp = 0; 194 return (n); 195 } 196 197 /* 198 * Send a single message to the TCP at address specified by 199 * the given TCP/IP header. If m == 0, then we make a copy 200 * of the tcpiphdr at ti and send directly to the addressed host. 201 * This is used to force keep alive messages out using the TCP 202 * template for a connection tp->t_template. If flags are given 203 * then we send a message back to the TCP which originated the 204 * segment ti, and discard the mbuf containing it and any other 205 * attached mbufs. 206 * 207 * In any case the ack and sequence number of the transmitted 208 * segment are as specified by the parameters. 209 * 210 * NOTE: If m != NULL, then ti must point to *inside* the mbuf. 211 */ 212 void 213 tcp_respond(tp, ti, m, ack, seq, flags) 214 struct tcpcb *tp; 215 register struct tcpiphdr *ti; 216 register struct mbuf *m; 217 tcp_seq ack, seq; 218 int flags; 219 { 220 register int tlen; 221 int win = 0; 222 struct route *ro = 0; 223 struct route sro; 224 225 if (tp) { 226 if (!(flags & TH_RST)) { 227 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 228 if (win > (long)TCP_MAXWIN << tp->rcv_scale) 229 win = (long)TCP_MAXWIN << tp->rcv_scale; 230 } 231 ro = &tp->t_inpcb->inp_route; 232 } else { 233 ro = &sro; 234 bzero(ro, sizeof *ro); 235 } 236 if (m == 0) { 237 m = m_gethdr(M_DONTWAIT, MT_HEADER); 238 if (m == NULL) 239 return; 240 #ifdef TCP_COMPAT_42 241 tlen = 1; 242 #else 243 tlen = 0; 244 #endif 245 m->m_data += max_linkhdr; 246 *mtod(m, struct tcpiphdr *) = *ti; 247 ti = mtod(m, struct tcpiphdr *); 248 flags = TH_ACK; 249 } else { 250 m_freem(m->m_next); 251 m->m_next = 0; 252 m->m_data = (caddr_t)ti; 253 m->m_len = sizeof (struct tcpiphdr); 254 tlen = 0; 255 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 256 xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, n_long); 257 xchg(ti->ti_dport, ti->ti_sport, n_short); 258 #undef xchg 259 } 260 ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen)); 261 tlen += sizeof (struct tcpiphdr); 262 m->m_len = tlen; 263 m->m_pkthdr.len = tlen; 264 m->m_pkthdr.rcvif = (struct ifnet *) 0; 265 bzero(ti->ti_x1, sizeof(ti->ti_x1)); 266 ti->ti_seq = htonl(seq); 267 ti->ti_ack = htonl(ack); 268 ti->ti_x2 = 0; 269 ti->ti_off = sizeof (struct tcphdr) >> 2; 270 ti->ti_flags = flags; 271 if (tp) 272 ti->ti_win = htons((u_short) (win >> tp->rcv_scale)); 273 else 274 ti->ti_win = htons((u_short)win); 275 ti->ti_urp = 0; 276 ti->ti_sum = 0; 277 ti->ti_sum = in_cksum(m, tlen); 278 ((struct ip *)ti)->ip_len = tlen; 279 ((struct ip *)ti)->ip_ttl = ip_defttl; 280 #ifdef TCPDEBUG 281 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 282 tcp_trace(TA_OUTPUT, 0, tp, ti, 0); 283 #endif 284 (void) ip_output(m, NULL, ro, 0, NULL); 285 if (ro == &sro && ro->ro_rt) { 286 RTFREE(ro->ro_rt); 287 } 288 } 289 290 /* 291 * Create a new TCP control block, making an 292 * empty reassembly queue and hooking it to the argument 293 * protocol control block. The `inp' parameter must have 294 * come from the zone allocator set up in tcp_init(). 295 */ 296 struct tcpcb * 297 tcp_newtcpcb(inp) 298 struct inpcb *inp; 299 { 300 struct inp_tp *it; 301 register struct tcpcb *tp; 302 303 it = (struct inp_tp *)inp; 304 tp = &it->tcb; 305 bzero((char *) tp, sizeof(struct tcpcb)); 306 tp->t_segq = NULL; 307 tp->t_maxseg = tp->t_maxopd = tcp_mssdflt; 308 309 if (tcp_do_rfc1323) 310 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); 311 if (tcp_do_rfc1644) 312 tp->t_flags |= TF_REQ_CC; 313 tp->t_inpcb = inp; /* XXX */ 314 /* 315 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no 316 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives 317 * reasonable initial retransmit time. 318 */ 319 tp->t_srtt = TCPTV_SRTTBASE; 320 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4; 321 tp->t_rttmin = TCPTV_MIN; 322 tp->t_rxtcur = TCPTV_RTOBASE; 323 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT; 324 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT; 325 inp->inp_ip_ttl = ip_defttl; 326 inp->inp_ppcb = (caddr_t)tp; 327 return (tp); /* XXX */ 328 } 329 330 /* 331 * Drop a TCP connection, reporting 332 * the specified error. If connection is synchronized, 333 * then send a RST to peer. 334 */ 335 struct tcpcb * 336 tcp_drop(tp, errno) 337 register struct tcpcb *tp; 338 int errno; 339 { 340 struct socket *so = tp->t_inpcb->inp_socket; 341 342 if (TCPS_HAVERCVDSYN(tp->t_state)) { 343 tp->t_state = TCPS_CLOSED; 344 (void) tcp_output(tp); 345 tcpstat.tcps_drops++; 346 } else 347 tcpstat.tcps_conndrops++; 348 if (errno == ETIMEDOUT && tp->t_softerror) 349 errno = tp->t_softerror; 350 so->so_error = errno; 351 return (tcp_close(tp)); 352 } 353 354 /* 355 * Close a TCP control block: 356 * discard all space held by the tcp 357 * discard internet protocol block 358 * wake up any sleepers 359 */ 360 struct tcpcb * 361 tcp_close(tp) 362 register struct tcpcb *tp; 363 { 364 register struct mbuf *q; 365 register struct mbuf *nq; 366 struct inpcb *inp = tp->t_inpcb; 367 struct socket *so = inp->inp_socket; 368 register struct rtentry *rt; 369 int dosavessthresh; 370 371 /* 372 * If we got enough samples through the srtt filter, 373 * save the rtt and rttvar in the routing entry. 374 * 'Enough' is arbitrarily defined as the 16 samples. 375 * 16 samples is enough for the srtt filter to converge 376 * to within 5% of the correct value; fewer samples and 377 * we could save a very bogus rtt. 378 * 379 * Don't update the default route's characteristics and don't 380 * update anything that the user "locked". 381 */ 382 if (tp->t_rttupdated >= 16 && 383 (rt = inp->inp_route.ro_rt) && 384 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr != INADDR_ANY) { 385 register u_long i = 0; 386 387 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { 388 i = tp->t_srtt * 389 (RTM_RTTUNIT / (PR_SLOWHZ * TCP_RTT_SCALE)); 390 if (rt->rt_rmx.rmx_rtt && i) 391 /* 392 * filter this update to half the old & half 393 * the new values, converting scale. 394 * See route.h and tcp_var.h for a 395 * description of the scaling constants. 396 */ 397 rt->rt_rmx.rmx_rtt = 398 (rt->rt_rmx.rmx_rtt + i) / 2; 399 else 400 rt->rt_rmx.rmx_rtt = i; 401 tcpstat.tcps_cachedrtt++; 402 } 403 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { 404 i = tp->t_rttvar * 405 (RTM_RTTUNIT / (PR_SLOWHZ * TCP_RTTVAR_SCALE)); 406 if (rt->rt_rmx.rmx_rttvar && i) 407 rt->rt_rmx.rmx_rttvar = 408 (rt->rt_rmx.rmx_rttvar + i) / 2; 409 else 410 rt->rt_rmx.rmx_rttvar = i; 411 tcpstat.tcps_cachedrttvar++; 412 } 413 /* 414 * The old comment here said: 415 * update the pipelimit (ssthresh) if it has been updated 416 * already or if a pipesize was specified & the threshhold 417 * got below half the pipesize. I.e., wait for bad news 418 * before we start updating, then update on both good 419 * and bad news. 420 * 421 * But we want to save the ssthresh even if no pipesize is 422 * specified explicitly in the route, because such 423 * connections still have an implicit pipesize specified 424 * by the global tcp_sendspace. In the absence of a reliable 425 * way to calculate the pipesize, it will have to do. 426 */ 427 i = tp->snd_ssthresh; 428 if (rt->rt_rmx.rmx_sendpipe != 0) 429 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2); 430 else 431 dosavessthresh = (i < so->so_snd.sb_hiwat / 2); 432 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && 433 i != 0 && rt->rt_rmx.rmx_ssthresh != 0) 434 || dosavessthresh) { 435 /* 436 * convert the limit from user data bytes to 437 * packets then to packet data bytes. 438 */ 439 i = (i + tp->t_maxseg / 2) / tp->t_maxseg; 440 if (i < 2) 441 i = 2; 442 i *= (u_long)(tp->t_maxseg + sizeof (struct tcpiphdr)); 443 if (rt->rt_rmx.rmx_ssthresh) 444 rt->rt_rmx.rmx_ssthresh = 445 (rt->rt_rmx.rmx_ssthresh + i) / 2; 446 else 447 rt->rt_rmx.rmx_ssthresh = i; 448 tcpstat.tcps_cachedssthresh++; 449 } 450 } 451 /* free the reassembly queue, if any */ 452 for (q = tp->t_segq; q; q = nq) { 453 nq = q->m_nextpkt; 454 tp->t_segq = nq; 455 m_freem(q); 456 } 457 if (tp->t_template) 458 (void) m_free(dtom(tp->t_template)); 459 inp->inp_ppcb = NULL; 460 soisdisconnected(so); 461 in_pcbdetach(inp); 462 tcpstat.tcps_closed++; 463 return ((struct tcpcb *)0); 464 } 465 466 void 467 tcp_drain() 468 { 469 470 } 471 472 /* 473 * Notify a tcp user of an asynchronous error; 474 * store error as soft error, but wake up user 475 * (for now, won't do anything until can select for soft error). 476 */ 477 static void 478 tcp_notify(inp, error) 479 struct inpcb *inp; 480 int error; 481 { 482 register struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 483 register struct socket *so = inp->inp_socket; 484 485 /* 486 * Ignore some errors if we are hooked up. 487 * If connection hasn't completed, has retransmitted several times, 488 * and receives a second error, give up now. This is better 489 * than waiting a long time to establish a connection that 490 * can never complete. 491 */ 492 if (tp->t_state == TCPS_ESTABLISHED && 493 (error == EHOSTUNREACH || error == ENETUNREACH || 494 error == EHOSTDOWN)) { 495 return; 496 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && 497 tp->t_softerror) 498 so->so_error = error; 499 else 500 tp->t_softerror = error; 501 wakeup((caddr_t) &so->so_timeo); 502 sorwakeup(so); 503 sowwakeup(so); 504 } 505 506 static int 507 tcp_pcblist SYSCTL_HANDLER_ARGS 508 { 509 int error, i, n, s; 510 struct inpcb *inp, **inp_list; 511 inp_gen_t gencnt; 512 struct xinpgen xig; 513 514 /* 515 * The process of preparing the TCB list is too time-consuming and 516 * resource-intensive to repeat twice on every request. 517 */ 518 if (req->oldptr == 0) { 519 n = tcbinfo.ipi_count; 520 req->oldidx = 2 * (sizeof xig) 521 + (n + n/8) * sizeof(struct xtcpcb); 522 return 0; 523 } 524 525 if (req->newptr != 0) 526 return EPERM; 527 528 /* 529 * OK, now we're committed to doing something. 530 */ 531 s = splnet(); 532 gencnt = tcbinfo.ipi_gencnt; 533 n = tcbinfo.ipi_count; 534 splx(s); 535 536 xig.xig_len = sizeof xig; 537 xig.xig_count = n; 538 xig.xig_gen = gencnt; 539 xig.xig_sogen = so_gencnt; 540 error = SYSCTL_OUT(req, &xig, sizeof xig); 541 if (error) 542 return error; 543 544 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 545 if (inp_list == 0) 546 return ENOMEM; 547 548 s = splnet(); 549 for (inp = tcbinfo.listhead->lh_first, i = 0; inp && i < n; 550 inp = inp->inp_list.le_next) { 551 if (inp->inp_gencnt <= gencnt) 552 inp_list[i++] = inp; 553 } 554 splx(s); 555 n = i; 556 557 error = 0; 558 for (i = 0; i < n; i++) { 559 inp = inp_list[i]; 560 if (inp->inp_gencnt <= gencnt) { 561 struct xtcpcb xt; 562 caddr_t inp_ppcb; 563 xt.xt_len = sizeof xt; 564 /* XXX should avoid extra copy */ 565 bcopy(inp, &xt.xt_inp, sizeof *inp); 566 inp_ppcb = inp->inp_ppcb; 567 if (inp_ppcb != NULL) 568 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp); 569 else 570 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); 571 if (inp->inp_socket) 572 sotoxsocket(inp->inp_socket, &xt.xt_socket); 573 error = SYSCTL_OUT(req, &xt, sizeof xt); 574 } 575 } 576 if (!error) { 577 /* 578 * Give the user an updated idea of our state. 579 * If the generation differs from what we told 580 * her before, she knows that something happened 581 * while we were processing this request, and it 582 * might be necessary to retry. 583 */ 584 s = splnet(); 585 xig.xig_gen = tcbinfo.ipi_gencnt; 586 xig.xig_sogen = so_gencnt; 587 xig.xig_count = tcbinfo.ipi_count; 588 splx(s); 589 error = SYSCTL_OUT(req, &xig, sizeof xig); 590 } 591 free(inp_list, M_TEMP); 592 return error; 593 } 594 595 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, 596 tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); 597 598 static int 599 tcp_getcred SYSCTL_HANDLER_ARGS 600 { 601 struct sockaddr_in addrs[2]; 602 struct inpcb *inp; 603 int error, s; 604 605 error = suser(req->p->p_ucred, &req->p->p_acflag); 606 if (error) 607 return (error); 608 609 if (req->newlen != sizeof(addrs)) 610 return (EINVAL); 611 if (req->oldlen != sizeof(struct ucred)) 612 return (EINVAL); 613 error = SYSCTL_IN(req, addrs, sizeof(addrs)); 614 if (error) 615 return (error); 616 s = splnet(); 617 inp = in_pcblookup_hash(&tcbinfo, addrs[1].sin_addr, addrs[1].sin_port, 618 addrs[0].sin_addr, addrs[0].sin_port, 0); 619 if (!inp || !inp->inp_socket || !inp->inp_socket->so_cred) { 620 error = ENOENT; 621 goto out; 622 } 623 error = SYSCTL_OUT(req, inp->inp_socket->so_cred->pc_ucred, 624 sizeof(struct ucred)); 625 626 out: 627 splx(s); 628 return (error); 629 } 630 631 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW, 0, 0, 632 tcp_getcred, "S,ucred", "Get the ucred of a TCP connection"); 633 634 void 635 tcp_ctlinput(cmd, sa, vip) 636 int cmd; 637 struct sockaddr *sa; 638 void *vip; 639 { 640 register struct ip *ip = vip; 641 register struct tcphdr *th; 642 void (*notify) __P((struct inpcb *, int)) = tcp_notify; 643 644 if (cmd == PRC_QUENCH) 645 notify = tcp_quench; 646 else if (cmd == PRC_MSGSIZE) 647 notify = tcp_mtudisc; 648 else if (PRC_IS_REDIRECT(cmd)) { 649 /* 650 * Redirects go to all references to the destination, 651 * and use in_rtchange to invalidate the route cache. 652 */ 653 ip = 0; 654 notify = in_rtchange; 655 } else if (cmd == PRC_HOSTDEAD) 656 /* 657 * Dead host indications: notify all references to the destination. 658 */ 659 ip = 0; 660 else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0) 661 return; 662 if (ip) { 663 th = (struct tcphdr *)((caddr_t)ip 664 + (IP_VHL_HL(ip->ip_vhl) << 2)); 665 in_pcbnotify(&tcb, sa, th->th_dport, ip->ip_src, th->th_sport, 666 cmd, notify); 667 } else 668 in_pcbnotifyall(&tcb, sa, cmd, notify); 669 } 670 671 #define TCP_RNDISS_ROUNDS 16 672 #define TCP_RNDISS_OUT 7200 673 #define TCP_RNDISS_MAX 30000 674 675 u_int8_t tcp_rndiss_sbox[128]; 676 u_int16_t tcp_rndiss_msb; 677 u_int16_t tcp_rndiss_cnt; 678 long tcp_rndiss_reseed; 679 680 u_int16_t 681 tcp_rndiss_encrypt(val) 682 u_int16_t val; 683 { 684 u_int16_t sum = 0, i; 685 686 for (i = 0; i < TCP_RNDISS_ROUNDS; i++) { 687 sum += 0x79b9; 688 val ^= ((u_int16_t)tcp_rndiss_sbox[(val^sum) & 0x7f]) << 7; 689 val = ((val & 0xff) << 7) | (val >> 8); 690 } 691 692 return val; 693 } 694 695 void 696 tcp_rndiss_init() 697 { 698 struct timeval time; 699 700 getmicrotime(&time); 701 read_random_unlimited(tcp_rndiss_sbox, sizeof(tcp_rndiss_sbox)); 702 703 tcp_rndiss_reseed = time.tv_sec + TCP_RNDISS_OUT; 704 tcp_rndiss_msb = tcp_rndiss_msb == 0x8000 ? 0 : 0x8000; 705 tcp_rndiss_cnt = 0; 706 } 707 708 tcp_seq 709 tcp_rndiss_next() 710 { 711 u_int32_t tmp; 712 struct timeval time; 713 714 getmicrotime(&time); 715 716 if (tcp_rndiss_cnt >= TCP_RNDISS_MAX || 717 time.tv_sec > tcp_rndiss_reseed) 718 tcp_rndiss_init(); 719 720 tmp = arc4random(); 721 722 /* (tmp & 0x7fff) ensures a 32768 byte gap between ISS */ 723 return ((tcp_rndiss_encrypt(tcp_rndiss_cnt++) | tcp_rndiss_msb) <<16) | 724 (tmp & 0x7fff); 725 } 726 727 /* 728 * When a source quench is received, close congestion window 729 * to one segment. We will gradually open it again as we proceed. 730 */ 731 void 732 tcp_quench(inp, errno) 733 struct inpcb *inp; 734 int errno; 735 { 736 struct tcpcb *tp = intotcpcb(inp); 737 738 if (tp) 739 tp->snd_cwnd = tp->t_maxseg; 740 } 741 742 /* 743 * When `need fragmentation' ICMP is received, update our idea of the MSS 744 * based on the new value in the route. Also nudge TCP to send something, 745 * since we know the packet we just sent was dropped. 746 * This duplicates some code in the tcp_mss() function in tcp_input.c. 747 */ 748 void 749 tcp_mtudisc(inp, errno) 750 struct inpcb *inp; 751 int errno; 752 { 753 struct tcpcb *tp = intotcpcb(inp); 754 struct rtentry *rt; 755 struct rmxp_tao *taop; 756 struct socket *so = inp->inp_socket; 757 int offered; 758 int mss; 759 760 if (tp) { 761 rt = tcp_rtlookup(inp); 762 if (!rt || !rt->rt_rmx.rmx_mtu) { 763 tp->t_maxopd = tp->t_maxseg = tcp_mssdflt; 764 return; 765 } 766 taop = rmx_taop(rt->rt_rmx); 767 offered = taop->tao_mssopt; 768 mss = rt->rt_rmx.rmx_mtu - sizeof(struct tcpiphdr); 769 if (offered) 770 mss = min(mss, offered); 771 /* 772 * XXX - The above conditional probably violates the TCP 773 * spec. The problem is that, since we don't know the 774 * other end's MSS, we are supposed to use a conservative 775 * default. But, if we do that, then MTU discovery will 776 * never actually take place, because the conservative 777 * default is much less than the MTUs typically seen 778 * on the Internet today. For the moment, we'll sweep 779 * this under the carpet. 780 * 781 * The conservative default might not actually be a problem 782 * if the only case this occurs is when sending an initial 783 * SYN with options and data to a host we've never talked 784 * to before. Then, they will reply with an MSS value which 785 * will get recorded and the new parameters should get 786 * recomputed. For Further Study. 787 */ 788 if (tp->t_maxopd <= mss) 789 return; 790 tp->t_maxopd = mss; 791 792 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && 793 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) 794 mss -= TCPOLEN_TSTAMP_APPA; 795 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC && 796 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC) 797 mss -= TCPOLEN_CC_APPA; 798 #if (MCLBYTES & (MCLBYTES - 1)) == 0 799 if (mss > MCLBYTES) 800 mss &= ~(MCLBYTES-1); 801 #else 802 if (mss > MCLBYTES) 803 mss = mss / MCLBYTES * MCLBYTES; 804 #endif 805 if (so->so_snd.sb_hiwat < mss) 806 mss = so->so_snd.sb_hiwat; 807 808 tp->t_maxseg = mss; 809 810 tcpstat.tcps_mturesent++; 811 tp->t_rtt = 0; 812 tp->snd_nxt = tp->snd_una; 813 tcp_output(tp); 814 } 815 } 816 817 /* 818 * Look-up the routing entry to the peer of this inpcb. If no route 819 * is found and it cannot be allocated the return NULL. This routine 820 * is called by TCP routines that access the rmx structure and by tcp_mss 821 * to get the interface MTU. 822 */ 823 struct rtentry * 824 tcp_rtlookup(inp) 825 struct inpcb *inp; 826 { 827 struct route *ro; 828 struct rtentry *rt; 829 830 ro = &inp->inp_route; 831 rt = ro->ro_rt; 832 if (rt == NULL || !(rt->rt_flags & RTF_UP)) { 833 /* No route yet, so try to acquire one */ 834 if (inp->inp_faddr.s_addr != INADDR_ANY) { 835 ro->ro_dst.sa_family = AF_INET; 836 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 837 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = 838 inp->inp_faddr; 839 rtalloc(ro); 840 rt = ro->ro_rt; 841 } 842 } 843 return rt; 844 } 845 846 /* 847 * Return a pointer to the cached information about the remote host. 848 * The cached information is stored in the protocol specific part of 849 * the route metrics. 850 */ 851 struct rmxp_tao * 852 tcp_gettaocache(inp) 853 struct inpcb *inp; 854 { 855 struct rtentry *rt = tcp_rtlookup(inp); 856 857 /* Make sure this is a host route and is up. */ 858 if (rt == NULL || 859 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)) 860 return NULL; 861 862 return rmx_taop(rt->rt_rmx); 863 } 864 865 /* 866 * Clear all the TAO cache entries, called from tcp_init. 867 * 868 * XXX 869 * This routine is just an empty one, because we assume that the routing 870 * routing tables are initialized at the same time when TCP, so there is 871 * nothing in the cache left over. 872 */ 873 static void 874 tcp_cleartaocache() 875 { 876 }
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