1 /* $OpenBSD: dispatch.c,v 1.31 2004/09/21 04:07:03 david Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-3-Clause 5 * 6 * Copyright 2004 Henning Brauer <henning@openbsd.org> 7 * Copyright (c) 1995, 1996, 1997, 1998, 1999 8 * The Internet Software Consortium. All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of The Internet Software Consortium nor the names 20 * of its contributors may be used to endorse or promote products derived 21 * from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND 24 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 25 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 27 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR 28 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 29 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 30 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 31 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 32 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 33 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 34 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * This software has been written for the Internet Software Consortium 38 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie 39 * Enterprises. To learn more about the Internet Software Consortium, 40 * see ``http://www.vix.com/isc''. To learn more about Vixie 41 * Enterprises, see ``http://www.vix.com''. 42 */ 43 44 #include <sys/cdefs.h> 45 __FBSDID("$FreeBSD$"); 46 47 #include "dhcpd.h" 48 #include "privsep.h" 49 50 #include <sys/ioctl.h> 51 52 #include <assert.h> 53 #include <net/if_media.h> 54 #include <ifaddrs.h> 55 #include <poll.h> 56 57 /* Assert that pointer p is aligned to at least align bytes */ 58 #define assert_aligned(p, align) assert((((uintptr_t)p) & ((align) - 1)) == 0) 59 60 static struct protocol *protocols; 61 static struct timeout *timeouts; 62 static struct timeout *free_timeouts; 63 static int interfaces_invalidated; 64 void (*bootp_packet_handler)(struct interface_info *, 65 struct dhcp_packet *, int, unsigned int, 66 struct iaddr, struct hardware *); 67 68 static int interface_status(struct interface_info *ifinfo); 69 70 /* 71 * Use getifaddrs() to get a list of all the attached interfaces. For 72 * each interface that's of type INET and not the loopback interface, 73 * register that interface with the network I/O software, figure out 74 * what subnet it's on, and add it to the list of interfaces. 75 */ 76 void 77 discover_interfaces(struct interface_info *iface) 78 { 79 struct ifaddrs *ifap, *ifa; 80 struct ifreq *tif; 81 82 if (getifaddrs(&ifap) != 0) 83 error("getifaddrs failed"); 84 85 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 86 if ((ifa->ifa_flags & IFF_LOOPBACK) || 87 (ifa->ifa_flags & IFF_POINTOPOINT) || 88 (!(ifa->ifa_flags & IFF_UP))) 89 continue; 90 91 if (strcmp(iface->name, ifa->ifa_name)) 92 continue; 93 94 /* 95 * If we have the capability, extract link information 96 * and record it in a linked list. 97 */ 98 if (ifa->ifa_addr->sa_family == AF_LINK) { 99 struct sockaddr_dl *foo; 100 101 /* 102 * The implementation of getifaddrs should guarantee 103 * this alignment 104 */ 105 assert_aligned(ifa->ifa_addr, 106 _Alignof(struct sockaddr_dl)); 107 #ifdef __clang__ 108 #pragma clang diagnostic push 109 #pragma clang diagnostic ignored "-Wcast-align" 110 #endif 111 foo = (struct sockaddr_dl *)ifa->ifa_addr; 112 #ifdef __clang__ 113 #pragma clang diagnostic pop 114 #endif 115 116 iface->index = foo->sdl_index; 117 iface->hw_address.hlen = foo->sdl_alen; 118 iface->hw_address.htype = HTYPE_ETHER; /* XXX */ 119 memcpy(iface->hw_address.haddr, 120 LLADDR(foo), foo->sdl_alen); 121 } else if (ifa->ifa_addr->sa_family == AF_INET) { 122 struct sockaddr_in foo; 123 struct iaddr addr; 124 125 memcpy(&foo, ifa->ifa_addr, sizeof(foo)); 126 if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK)) 127 continue; 128 if (!iface->ifp) { 129 if ((tif = calloc(1, sizeof(struct ifreq))) 130 == NULL) 131 error("no space to remember ifp"); 132 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ); 133 memcpy(&tif->ifr_addr, ifa->ifa_addr, 134 ifa->ifa_addr->sa_len); 135 iface->ifp = tif; 136 iface->primary_address = foo.sin_addr; 137 } 138 addr.len = 4; 139 memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len); 140 } 141 } 142 143 if (!iface->ifp) 144 error("%s: not found", iface->name); 145 146 /* Register the interface... */ 147 if_register_receive(iface); 148 if_register_send(iface); 149 add_protocol(iface->name, iface->rfdesc, got_one, iface); 150 freeifaddrs(ifap); 151 } 152 153 void 154 reinitialize_interfaces(void) 155 { 156 interfaces_invalidated = 1; 157 } 158 159 /* 160 * Wait for packets to come in using poll(). When a packet comes in, 161 * call receive_packet to receive the packet and possibly strip hardware 162 * addressing information from it, and then call through the 163 * bootp_packet_handler hook to try to do something with it. 164 */ 165 void 166 dispatch(void) 167 { 168 int count, live_interfaces, i, to_msec, nfds = 0; 169 struct protocol *l; 170 struct pollfd *fds; 171 time_t howlong; 172 173 for (l = protocols; l; l = l->next) 174 nfds++; 175 176 fds = malloc(nfds * sizeof(struct pollfd)); 177 if (fds == NULL) 178 error("Can't allocate poll structures."); 179 180 do { 181 /* 182 * Call any expired timeouts, and then if there's still 183 * a timeout registered, time out the select call then. 184 */ 185 another: 186 if (timeouts) { 187 struct timeout *t; 188 189 if (timeouts->when <= cur_time) { 190 t = timeouts; 191 timeouts = timeouts->next; 192 (*(t->func))(t->what); 193 t->next = free_timeouts; 194 free_timeouts = t; 195 goto another; 196 } 197 198 /* 199 * Figure timeout in milliseconds, and check for 200 * potential overflow, so we can cram into an 201 * int for poll, while not polling with a 202 * negative timeout and blocking indefinitely. 203 */ 204 howlong = timeouts->when - cur_time; 205 if (howlong > INT_MAX / 1000) 206 howlong = INT_MAX / 1000; 207 to_msec = howlong * 1000; 208 } else 209 to_msec = -1; 210 211 /* Set up the descriptors to be polled. */ 212 live_interfaces = 0; 213 for (i = 0, l = protocols; l; l = l->next) { 214 struct interface_info *ip = l->local; 215 216 if (ip == NULL || ip->dead) 217 continue; 218 fds[i].fd = l->fd; 219 fds[i].events = POLLIN; 220 fds[i].revents = 0; 221 i++; 222 if (l->handler == got_one) 223 live_interfaces++; 224 } 225 if (live_interfaces == 0) 226 error("No live interfaces to poll on - exiting."); 227 228 /* Wait for a packet or a timeout... XXX */ 229 count = poll(fds, nfds, to_msec); 230 231 /* Not likely to be transitory... */ 232 if (count == -1) { 233 if (errno == EAGAIN || errno == EINTR) { 234 time(&cur_time); 235 continue; 236 } else 237 error("poll: %m"); 238 } 239 240 /* Get the current time... */ 241 time(&cur_time); 242 243 i = 0; 244 for (l = protocols; l; l = l->next) { 245 struct interface_info *ip; 246 ip = l->local; 247 if ((fds[i].revents & (POLLIN | POLLHUP))) { 248 fds[i].revents = 0; 249 if (ip && (l->handler != got_one || 250 !ip->dead)) 251 (*(l->handler))(l); 252 if (interfaces_invalidated) 253 break; 254 } 255 i++; 256 } 257 interfaces_invalidated = 0; 258 } while (1); 259 } 260 261 262 void 263 got_one(struct protocol *l) 264 { 265 struct sockaddr_in from; 266 struct hardware hfrom; 267 struct iaddr ifrom; 268 ssize_t result; 269 union { 270 /* 271 * Packet input buffer. Must be as large as largest 272 * possible MTU. 273 */ 274 unsigned char packbuf[4095]; 275 struct dhcp_packet packet; 276 } u; 277 struct interface_info *ip = l->local; 278 279 if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from, 280 &hfrom)) == -1) { 281 warning("receive_packet failed on %s: %s", ip->name, 282 strerror(errno)); 283 ip->errors++; 284 if ((!interface_status(ip)) || 285 (ip->noifmedia && ip->errors > 20)) { 286 /* our interface has gone away. */ 287 warning("Interface %s no longer appears valid.", 288 ip->name); 289 ip->dead = 1; 290 interfaces_invalidated = 1; 291 close(l->fd); 292 remove_protocol(l); 293 free(ip); 294 } 295 return; 296 } 297 if (result == 0) 298 return; 299 300 if (bootp_packet_handler) { 301 ifrom.len = 4; 302 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len); 303 304 (*bootp_packet_handler)(ip, &u.packet, result, 305 from.sin_port, ifrom, &hfrom); 306 } 307 } 308 309 int 310 interface_status(struct interface_info *ifinfo) 311 { 312 char *ifname = ifinfo->name; 313 int ifsock = ifinfo->rfdesc; 314 struct ifreq ifr; 315 struct ifmediareq ifmr; 316 317 /* get interface flags */ 318 memset(&ifr, 0, sizeof(ifr)); 319 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 320 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) { 321 cap_syslog(capsyslog, LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", 322 ifname); 323 goto inactive; 324 } 325 326 /* 327 * if one of UP and RUNNING flags is dropped, 328 * the interface is not active. 329 */ 330 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) 331 goto inactive; 332 333 /* Next, check carrier on the interface, if possible */ 334 if (ifinfo->noifmedia) 335 goto active; 336 memset(&ifmr, 0, sizeof(ifmr)); 337 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 338 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) { 339 if (errno != EINVAL) { 340 cap_syslog(capsyslog, LOG_DEBUG, 341 "ioctl(SIOCGIFMEDIA) on %s: %m", ifname); 342 ifinfo->noifmedia = 1; 343 goto active; 344 } 345 /* 346 * EINVAL (or ENOTTY) simply means that the interface 347 * does not support the SIOCGIFMEDIA ioctl. We regard it alive. 348 */ 349 ifinfo->noifmedia = 1; 350 goto active; 351 } 352 if (ifmr.ifm_status & IFM_AVALID) { 353 switch (ifmr.ifm_active & IFM_NMASK) { 354 case IFM_ETHER: 355 case IFM_IEEE80211: 356 if (ifmr.ifm_status & IFM_ACTIVE) 357 goto active; 358 else 359 goto inactive; 360 break; 361 default: 362 goto inactive; 363 } 364 } 365 inactive: 366 return (0); 367 active: 368 return (1); 369 } 370 371 void 372 add_timeout(time_t when, void (*where)(void *), void *what) 373 { 374 struct timeout *t, *q; 375 376 /* See if this timeout supersedes an existing timeout. */ 377 t = NULL; 378 for (q = timeouts; q; q = q->next) { 379 if (q->func == where && q->what == what) { 380 if (t) 381 t->next = q->next; 382 else 383 timeouts = q->next; 384 break; 385 } 386 t = q; 387 } 388 389 /* If we didn't supersede a timeout, allocate a timeout 390 structure now. */ 391 if (!q) { 392 if (free_timeouts) { 393 q = free_timeouts; 394 free_timeouts = q->next; 395 q->func = where; 396 q->what = what; 397 } else { 398 q = malloc(sizeof(struct timeout)); 399 if (!q) 400 error("Can't allocate timeout structure!"); 401 q->func = where; 402 q->what = what; 403 } 404 } 405 406 q->when = when; 407 408 /* Now sort this timeout into the timeout list. */ 409 410 /* Beginning of list? */ 411 if (!timeouts || timeouts->when > q->when) { 412 q->next = timeouts; 413 timeouts = q; 414 return; 415 } 416 417 /* Middle of list? */ 418 for (t = timeouts; t->next; t = t->next) { 419 if (t->next->when > q->when) { 420 q->next = t->next; 421 t->next = q; 422 return; 423 } 424 } 425 426 /* End of list. */ 427 t->next = q; 428 q->next = NULL; 429 } 430 431 void 432 cancel_timeout(void (*where)(void *), void *what) 433 { 434 struct timeout *t, *q; 435 436 /* Look for this timeout on the list, and unlink it if we find it. */ 437 t = NULL; 438 for (q = timeouts; q; q = q->next) { 439 if (q->func == where && q->what == what) { 440 if (t) 441 t->next = q->next; 442 else 443 timeouts = q->next; 444 break; 445 } 446 t = q; 447 } 448 449 /* If we found the timeout, put it on the free list. */ 450 if (q) { 451 q->next = free_timeouts; 452 free_timeouts = q; 453 } 454 } 455 456 /* Add a protocol to the list of protocols... */ 457 void 458 add_protocol(const char *name, int fd, void (*handler)(struct protocol *), 459 void *local) 460 { 461 struct protocol *p; 462 463 p = malloc(sizeof(*p)); 464 if (!p) 465 error("can't allocate protocol struct for %s", name); 466 467 p->fd = fd; 468 p->handler = handler; 469 p->local = local; 470 p->next = protocols; 471 protocols = p; 472 } 473 474 void 475 remove_protocol(struct protocol *proto) 476 { 477 struct protocol *p, *prev; 478 479 for (p = protocols, prev = NULL; p != NULL; prev = p, p = p->next) { 480 if (p == proto) { 481 if (prev == NULL) 482 protocols = p->next; 483 else 484 prev->next = p->next; 485 free(p); 486 break; 487 } 488 } 489 } 490 491 int 492 interface_link_status(char *ifname) 493 { 494 struct ifmediareq ifmr; 495 int sock; 496 497 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 498 error("Can't create socket"); 499 500 memset(&ifmr, 0, sizeof(ifmr)); 501 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 502 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) { 503 /* EINVAL -> link state unknown. treat as active */ 504 if (errno != EINVAL) 505 cap_syslog(capsyslog, LOG_DEBUG, 506 "ioctl(SIOCGIFMEDIA) on %s: %m", ifname); 507 close(sock); 508 return (1); 509 } 510 close(sock); 511 512 if (ifmr.ifm_status & IFM_AVALID) { 513 switch (ifmr.ifm_active & IFM_NMASK) { 514 case IFM_ETHER: 515 case IFM_IEEE80211: 516 if (ifmr.ifm_status & IFM_ACTIVE) 517 return (1); 518 else 519 return (0); 520 } 521 } 522 return (1); 523 } 524 525 void 526 interface_set_mtu_unpriv(int privfd, u_int16_t mtu) 527 { 528 struct imsg_hdr hdr; 529 struct buf *buf; 530 int errs = 0; 531 532 hdr.code = IMSG_SET_INTERFACE_MTU; 533 hdr.len = sizeof(hdr) + 534 sizeof(u_int16_t); 535 536 if ((buf = buf_open(hdr.len)) == NULL) 537 error("buf_open: %m"); 538 539 errs += buf_add(buf, &hdr, sizeof(hdr)); 540 errs += buf_add(buf, &mtu, sizeof(mtu)); 541 if (errs) 542 error("buf_add: %m"); 543 544 if (buf_close(privfd, buf) == -1) 545 error("buf_close: %m"); 546 } 547 548 void 549 interface_set_mtu_priv(char *ifname, u_int16_t mtu) 550 { 551 struct ifreq ifr; 552 int sock; 553 u_int16_t old_mtu; 554 555 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 556 error("Can't create socket"); 557 558 memset(&ifr, 0, sizeof(ifr)); 559 old_mtu = 0; 560 561 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 562 563 if (ioctl(sock, SIOCGIFMTU, (caddr_t)&ifr) == -1) 564 warning("SIOCGIFMTU failed (%s): %s", ifname, 565 strerror(errno)); 566 else 567 old_mtu = ifr.ifr_mtu; 568 569 if (mtu != old_mtu) { 570 ifr.ifr_mtu = mtu; 571 572 if (ioctl(sock, SIOCSIFMTU, &ifr) == -1) 573 warning("SIOCSIFMTU failed (%d): %s", mtu, 574 strerror(errno)); 575 } 576 577 close(sock); 578 } 579