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 #include "dhcpd.h" 46 #include "privsep.h" 47 48 #include <sys/ioctl.h> 49 50 #include <assert.h> 51 #include <net/if_media.h> 52 #include <ifaddrs.h> 53 #include <poll.h> 54 55 /* Assert that pointer p is aligned to at least align bytes */ 56 #define assert_aligned(p, align) assert((((uintptr_t)p) & ((align) - 1)) == 0) 57 58 static struct protocol *protocols; 59 static struct timeout *timeouts; 60 static struct timeout *free_timeouts; 61 static int interfaces_invalidated; 62 void (*bootp_packet_handler)(struct interface_info *, 63 struct dhcp_packet *, int, unsigned int, 64 struct iaddr, struct hardware *); 65 66 static int interface_status(struct interface_info *ifinfo); 67 68 /* 69 * Use getifaddrs() to get a list of all the attached interfaces. For 70 * each interface that's of type INET and not the loopback interface, 71 * register that interface with the network I/O software, figure out 72 * what subnet it's on, and add it to the list of interfaces. 73 */ 74 void 75 discover_interfaces(struct interface_info *iface) 76 { 77 struct ifaddrs *ifap, *ifa; 78 struct ifreq *tif; 79 int len = IFNAMSIZ + sizeof(struct sockaddr_storage); 80 81 if (getifaddrs(&ifap) != 0) 82 error("getifaddrs failed"); 83 84 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 85 if ((ifa->ifa_flags & IFF_LOOPBACK) || 86 (ifa->ifa_flags & IFF_POINTOPOINT) || 87 (!(ifa->ifa_flags & IFF_UP))) 88 continue; 89 90 if (strcmp(iface->name, ifa->ifa_name)) 91 continue; 92 93 /* 94 * If we have the capability, extract link information 95 * and record it in a linked list. 96 */ 97 if (ifa->ifa_addr->sa_family == AF_LINK) { 98 struct sockaddr_dl *foo; 99 100 /* 101 * The implementation of getifaddrs should guarantee 102 * this alignment 103 */ 104 assert_aligned(ifa->ifa_addr, 105 _Alignof(struct sockaddr_dl)); 106 #ifdef __clang__ 107 #pragma clang diagnostic push 108 #pragma clang diagnostic ignored "-Wcast-align" 109 #endif 110 foo = (struct sockaddr_dl *)ifa->ifa_addr; 111 #ifdef __clang__ 112 #pragma clang diagnostic pop 113 #endif 114 115 iface->index = foo->sdl_index; 116 iface->hw_address.hlen = foo->sdl_alen; 117 iface->hw_address.htype = HTYPE_ETHER; /* XXX */ 118 memcpy(iface->hw_address.haddr, 119 LLADDR(foo), foo->sdl_alen); 120 } 121 if (!iface->ifp) { 122 if ((tif = calloc(1, len)) == NULL) 123 error("no space to remember ifp"); 124 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ); 125 iface->ifp = tif; 126 } 127 128 } 129 130 if (!iface->ifp) 131 error("%s: not found", iface->name); 132 133 /* Register the interface... */ 134 if_register_receive(iface); 135 if_register_send(iface); 136 add_protocol(iface->name, iface->rfdesc, got_one, iface); 137 freeifaddrs(ifap); 138 } 139 140 void 141 reinitialize_interfaces(void) 142 { 143 interfaces_invalidated = 1; 144 } 145 146 /* 147 * Wait for packets to come in using poll(). When a packet comes in, 148 * call receive_packet to receive the packet and possibly strip hardware 149 * addressing information from it, and then call through the 150 * bootp_packet_handler hook to try to do something with it. 151 */ 152 void 153 dispatch(void) 154 { 155 int count, live_interfaces, i, to_msec, nfds = 0; 156 struct protocol *l; 157 struct pollfd *fds; 158 time_t howlong; 159 160 for (l = protocols; l; l = l->next) 161 nfds++; 162 163 fds = malloc(nfds * sizeof(struct pollfd)); 164 if (fds == NULL) 165 error("Can't allocate poll structures."); 166 167 do { 168 /* 169 * Call any expired timeouts, and then if there's still 170 * a timeout registered, time out the select call then. 171 */ 172 another: 173 if (timeouts) { 174 struct timeout *t; 175 176 if (timeouts->when <= cur_time) { 177 t = timeouts; 178 timeouts = timeouts->next; 179 (*(t->func))(t->what); 180 t->next = free_timeouts; 181 free_timeouts = t; 182 goto another; 183 } 184 185 /* 186 * Figure timeout in milliseconds, and check for 187 * potential overflow, so we can cram into an 188 * int for poll, while not polling with a 189 * negative timeout and blocking indefinitely. 190 */ 191 howlong = timeouts->when - cur_time; 192 if (howlong > INT_MAX / 1000) 193 howlong = INT_MAX / 1000; 194 to_msec = howlong * 1000; 195 } else 196 to_msec = -1; 197 198 /* Set up the descriptors to be polled. */ 199 live_interfaces = 0; 200 for (i = 0, l = protocols; l; l = l->next) { 201 struct interface_info *ip = l->local; 202 203 if (ip == NULL || ip->dead) 204 continue; 205 fds[i].fd = l->fd; 206 fds[i].events = POLLIN; 207 fds[i].revents = 0; 208 i++; 209 if (l->handler == got_one) 210 live_interfaces++; 211 } 212 if (live_interfaces == 0) 213 error("No live interfaces to poll on - exiting."); 214 215 /* Wait for a packet or a timeout... XXX */ 216 count = poll(fds, nfds, to_msec); 217 218 /* Not likely to be transitory... */ 219 if (count == -1) { 220 if (errno == EAGAIN || errno == EINTR) { 221 time(&cur_time); 222 continue; 223 } else 224 error("poll: %m"); 225 } 226 227 /* Get the current time... */ 228 time(&cur_time); 229 230 i = 0; 231 for (l = protocols; l; l = l->next) { 232 struct interface_info *ip; 233 ip = l->local; 234 if ((fds[i].revents & (POLLIN | POLLHUP))) { 235 fds[i].revents = 0; 236 if (ip && (l->handler != got_one || 237 !ip->dead)) 238 (*(l->handler))(l); 239 if (interfaces_invalidated) 240 break; 241 } 242 i++; 243 } 244 interfaces_invalidated = 0; 245 } while (1); 246 } 247 248 249 void 250 got_one(struct protocol *l) 251 { 252 struct sockaddr_in from; 253 struct hardware hfrom; 254 struct iaddr ifrom; 255 ssize_t result; 256 union { 257 /* 258 * Packet input buffer. Must be as large as largest 259 * possible MTU. 260 */ 261 unsigned char packbuf[4095]; 262 struct dhcp_packet packet; 263 } u; 264 struct interface_info *ip = l->local; 265 266 if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from, 267 &hfrom)) == -1) { 268 warning("receive_packet failed on %s: %s", ip->name, 269 strerror(errno)); 270 ip->errors++; 271 if ((!interface_status(ip)) || 272 (ip->noifmedia && ip->errors > 20)) { 273 /* our interface has gone away. */ 274 warning("Interface %s no longer appears valid.", 275 ip->name); 276 ip->dead = 1; 277 interfaces_invalidated = 1; 278 close(l->fd); 279 remove_protocol(l); 280 free(ip); 281 } 282 return; 283 } 284 if (result == 0) 285 return; 286 287 if (bootp_packet_handler) { 288 ifrom.len = 4; 289 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len); 290 291 (*bootp_packet_handler)(ip, &u.packet, result, 292 from.sin_port, ifrom, &hfrom); 293 } 294 } 295 296 int 297 interface_status(struct interface_info *ifinfo) 298 { 299 char *ifname = ifinfo->name; 300 int ifsock = ifinfo->rfdesc; 301 struct ifreq ifr; 302 struct ifmediareq ifmr; 303 304 /* get interface flags */ 305 memset(&ifr, 0, sizeof(ifr)); 306 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 307 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) { 308 cap_syslog(capsyslog, LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", 309 ifname); 310 goto inactive; 311 } 312 313 /* 314 * if one of UP and RUNNING flags is dropped, 315 * the interface is not active. 316 */ 317 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) 318 goto inactive; 319 320 /* Next, check carrier on the interface, if possible */ 321 if (ifinfo->noifmedia) 322 goto active; 323 memset(&ifmr, 0, sizeof(ifmr)); 324 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 325 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) { 326 if (errno != EINVAL) { 327 cap_syslog(capsyslog, LOG_DEBUG, 328 "ioctl(SIOCGIFMEDIA) on %s: %m", ifname); 329 ifinfo->noifmedia = 1; 330 goto active; 331 } 332 /* 333 * EINVAL (or ENOTTY) simply means that the interface 334 * does not support the SIOCGIFMEDIA ioctl. We regard it alive. 335 */ 336 ifinfo->noifmedia = 1; 337 goto active; 338 } 339 if (ifmr.ifm_status & IFM_AVALID) { 340 switch (ifmr.ifm_active & IFM_NMASK) { 341 case IFM_ETHER: 342 case IFM_IEEE80211: 343 if (ifmr.ifm_status & IFM_ACTIVE) 344 goto active; 345 else 346 goto inactive; 347 break; 348 default: 349 goto inactive; 350 } 351 } 352 inactive: 353 return (0); 354 active: 355 return (1); 356 } 357 358 void 359 add_timeout(time_t when, void (*where)(void *), void *what) 360 { 361 struct timeout *t, *q; 362 363 /* See if this timeout supersedes an existing timeout. */ 364 t = NULL; 365 for (q = timeouts; q; q = q->next) { 366 if (q->func == where && q->what == what) { 367 if (t) 368 t->next = q->next; 369 else 370 timeouts = q->next; 371 break; 372 } 373 t = q; 374 } 375 376 /* If we didn't supersede a timeout, allocate a timeout 377 structure now. */ 378 if (!q) { 379 if (free_timeouts) { 380 q = free_timeouts; 381 free_timeouts = q->next; 382 q->func = where; 383 q->what = what; 384 } else { 385 q = malloc(sizeof(struct timeout)); 386 if (!q) 387 error("Can't allocate timeout structure!"); 388 q->func = where; 389 q->what = what; 390 } 391 } 392 393 q->when = when; 394 395 /* Now sort this timeout into the timeout list. */ 396 397 /* Beginning of list? */ 398 if (!timeouts || timeouts->when > q->when) { 399 q->next = timeouts; 400 timeouts = q; 401 return; 402 } 403 404 /* Middle of list? */ 405 for (t = timeouts; t->next; t = t->next) { 406 if (t->next->when > q->when) { 407 q->next = t->next; 408 t->next = q; 409 return; 410 } 411 } 412 413 /* End of list. */ 414 t->next = q; 415 q->next = NULL; 416 } 417 418 void 419 cancel_timeout(void (*where)(void *), void *what) 420 { 421 struct timeout *t, *q; 422 423 /* Look for this timeout on the list, and unlink it if we find it. */ 424 t = NULL; 425 for (q = timeouts; q; q = q->next) { 426 if (q->func == where && q->what == what) { 427 if (t) 428 t->next = q->next; 429 else 430 timeouts = q->next; 431 break; 432 } 433 t = q; 434 } 435 436 /* If we found the timeout, put it on the free list. */ 437 if (q) { 438 q->next = free_timeouts; 439 free_timeouts = q; 440 } 441 } 442 443 /* Add a protocol to the list of protocols... */ 444 void 445 add_protocol(const char *name, int fd, void (*handler)(struct protocol *), 446 void *local) 447 { 448 struct protocol *p; 449 450 p = malloc(sizeof(*p)); 451 if (!p) 452 error("can't allocate protocol struct for %s", name); 453 454 p->fd = fd; 455 p->handler = handler; 456 p->local = local; 457 p->next = protocols; 458 protocols = p; 459 } 460 461 void 462 remove_protocol(struct protocol *proto) 463 { 464 struct protocol *p, *prev; 465 466 for (p = protocols, prev = NULL; p != NULL; prev = p, p = p->next) { 467 if (p == proto) { 468 if (prev == NULL) 469 protocols = p->next; 470 else 471 prev->next = p->next; 472 free(p); 473 break; 474 } 475 } 476 } 477 478 int 479 interface_link_status(char *ifname) 480 { 481 struct ifmediareq ifmr; 482 int sock; 483 484 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 485 error("Can't create socket"); 486 487 memset(&ifmr, 0, sizeof(ifmr)); 488 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 489 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) { 490 /* EINVAL -> link state unknown. treat as active */ 491 if (errno != EINVAL) 492 cap_syslog(capsyslog, LOG_DEBUG, 493 "ioctl(SIOCGIFMEDIA) on %s: %m", ifname); 494 close(sock); 495 return (1); 496 } 497 close(sock); 498 499 if (ifmr.ifm_status & IFM_AVALID) { 500 switch (ifmr.ifm_active & IFM_NMASK) { 501 case IFM_ETHER: 502 case IFM_IEEE80211: 503 if (ifmr.ifm_status & IFM_ACTIVE) 504 return (1); 505 else 506 return (0); 507 } 508 } 509 return (1); 510 } 511 512 void 513 interface_set_mtu_unpriv(int privfd, u_int16_t mtu) 514 { 515 struct imsg_hdr hdr; 516 struct buf *buf; 517 int errs = 0; 518 519 hdr.code = IMSG_SET_INTERFACE_MTU; 520 hdr.len = sizeof(hdr) + 521 sizeof(u_int16_t); 522 523 if ((buf = buf_open(hdr.len)) == NULL) 524 error("buf_open: %m"); 525 526 errs += buf_add(buf, &hdr, sizeof(hdr)); 527 errs += buf_add(buf, &mtu, sizeof(mtu)); 528 if (errs) 529 error("buf_add: %m"); 530 531 if (buf_close(privfd, buf) == -1) 532 error("buf_close: %m"); 533 } 534 535 void 536 interface_set_mtu_priv(char *ifname, u_int16_t mtu) 537 { 538 struct ifreq ifr; 539 int sock; 540 u_int16_t old_mtu; 541 542 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 543 error("Can't create socket"); 544 545 memset(&ifr, 0, sizeof(ifr)); 546 old_mtu = 0; 547 548 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 549 550 if (ioctl(sock, SIOCGIFMTU, (caddr_t)&ifr) == -1) 551 warning("SIOCGIFMTU failed (%s): %s", ifname, 552 strerror(errno)); 553 else 554 old_mtu = ifr.ifr_mtu; 555 556 if (mtu != old_mtu) { 557 ifr.ifr_mtu = mtu; 558 559 if (ioctl(sock, SIOCSIFMTU, &ifr) == -1) 560 warning("SIOCSIFMTU failed (%d): %s", mtu, 561 strerror(errno)); 562 } 563 564 close(sock); 565 } 566