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