1/* $OpenBSD: dispatch.c,v 1.31 2004/09/21 04:07:03 david Exp $ */ 2 3/* 4 * Copyright 2004 Henning Brauer <henning@openbsd.org> 5 * Copyright (c) 1995, 1996, 1997, 1998, 1999 6 * The Internet Software Consortium. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of The Internet Software Consortium nor the names 18 * of its contributors may be used to endorse or promote products derived 19 * from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND 22 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 23 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 25 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR 26 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 28 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 29 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 30 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 31 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 32 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * This software has been written for the Internet Software Consortium 36 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie 37 * Enterprises. To learn more about the Internet Software Consortium, 38 * see ``http://www.vix.com/isc''. To learn more about Vixie 39 * Enterprises, see ``http://www.vix.com''. 40 */ 41 42#include <sys/cdefs.h> 43__FBSDID("$FreeBSD: stable/11/sbin/dhclient/dispatch.c 336440 2018-07-18 01:57:13Z eugen $"); 44 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 58struct protocol *protocols; 59struct timeout *timeouts; 60static struct timeout *free_timeouts; 61static int interfaces_invalidated; 62void (*bootp_packet_handler)(struct interface_info *, 63 struct dhcp_packet *, int, unsigned int, 64 struct iaddr, struct hardware *); 65 66static 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 */ 74void 75discover_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 } else if (ifa->ifa_addr->sa_family == AF_INET) { 120 struct sockaddr_in foo; 121 struct iaddr addr; 122 123 memcpy(&foo, ifa->ifa_addr, sizeof(foo)); 124 if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK)) 125 continue; 126 if (!iface->ifp) { 127 if ((tif = calloc(1, sizeof(struct ifreq))) 128 == NULL) 129 error("no space to remember ifp"); 130 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ); 131 memcpy(&tif->ifr_addr, ifa->ifa_addr, 132 ifa->ifa_addr->sa_len); 133 iface->ifp = tif; 134 iface->primary_address = foo.sin_addr; 135 } 136 addr.len = 4; 137 memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len); 138 } 139 } 140 141 if (!iface->ifp) 142 error("%s: not found", iface->name); 143 144 /* Register the interface... */ 145 if_register_receive(iface); 146 if_register_send(iface); 147 add_protocol(iface->name, iface->rfdesc, got_one, iface); 148 freeifaddrs(ifap); 149} 150 151void 152reinitialize_interfaces(void) 153{ 154 interfaces_invalidated = 1; 155} 156 157/* 158 * Wait for packets to come in using poll(). When a packet comes in, 159 * call receive_packet to receive the packet and possibly strip hardware 160 * addressing information from it, and then call through the 161 * bootp_packet_handler hook to try to do something with it. 162 */ 163void 164dispatch(void) 165{ 166 int count, live_interfaces, i, to_msec, nfds = 0; 167 struct protocol *l; 168 struct pollfd *fds; 169 time_t howlong; 170 171 for (l = protocols; l; l = l->next) 172 nfds++; 173 174 fds = malloc(nfds * sizeof(struct pollfd)); 175 if (fds == NULL) 176 error("Can't allocate poll structures."); 177 178 do { 179 /* 180 * Call any expired timeouts, and then if there's still 181 * a timeout registered, time out the select call then. 182 */ 183another: 184 if (timeouts) { 185 struct timeout *t; 186 187 if (timeouts->when <= cur_time) { 188 t = timeouts; 189 timeouts = timeouts->next; 190 (*(t->func))(t->what); 191 t->next = free_timeouts; 192 free_timeouts = t; 193 goto another; 194 } 195 196 /* 197 * Figure timeout in milliseconds, and check for 198 * potential overflow, so we can cram into an 199 * int for poll, while not polling with a 200 * negative timeout and blocking indefinitely. 201 */ 202 howlong = timeouts->when - cur_time; 203 if (howlong > INT_MAX / 1000) 204 howlong = INT_MAX / 1000; 205 to_msec = howlong * 1000; 206 } else 207 to_msec = -1; 208 209 /* Set up the descriptors to be polled. */ 210 live_interfaces = 0; 211 for (i = 0, l = protocols; l; l = l->next) { 212 struct interface_info *ip = l->local; 213 214 if (ip == NULL || ip->dead) 215 continue; 216 fds[i].fd = l->fd; 217 fds[i].events = POLLIN; 218 fds[i].revents = 0; 219 i++; 220 if (l->handler == got_one) 221 live_interfaces++; 222 } 223 if (live_interfaces == 0) 224 error("No live interfaces to poll on - exiting."); 225 226 /* Wait for a packet or a timeout... XXX */ 227 count = poll(fds, nfds, to_msec); 228 229 /* Not likely to be transitory... */ 230 if (count == -1) { 231 if (errno == EAGAIN || errno == EINTR) { 232 time(&cur_time); 233 continue; 234 } else 235 error("poll: %m"); 236 } 237 238 /* Get the current time... */ 239 time(&cur_time); 240 241 i = 0; 242 for (l = protocols; l; l = l->next) { 243 struct interface_info *ip; 244 ip = l->local; 245 if ((fds[i].revents & (POLLIN | POLLHUP))) { 246 fds[i].revents = 0; 247 if (ip && (l->handler != got_one || 248 !ip->dead)) 249 (*(l->handler))(l); 250 if (interfaces_invalidated) 251 break; 252 } 253 i++; 254 } 255 interfaces_invalidated = 0; 256 } while (1); 257} 258 259 260void 261got_one(struct protocol *l) 262{ 263 struct sockaddr_in from; 264 struct hardware hfrom; 265 struct iaddr ifrom; 266 ssize_t result; 267 union { 268 /* 269 * Packet input buffer. Must be as large as largest 270 * possible MTU. 271 */ 272 unsigned char packbuf[4095]; 273 struct dhcp_packet packet; 274 } u; 275 struct interface_info *ip = l->local; 276 277 if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from, 278 &hfrom)) == -1) { 279 warning("receive_packet failed on %s: %s", ip->name, 280 strerror(errno)); 281 ip->errors++; 282 if ((!interface_status(ip)) || 283 (ip->noifmedia && ip->errors > 20)) { 284 /* our interface has gone away. */ 285 warning("Interface %s no longer appears valid.", 286 ip->name); 287 ip->dead = 1; 288 interfaces_invalidated = 1; 289 close(l->fd); 290 remove_protocol(l); 291 free(ip); 292 } 293 return; 294 } 295 if (result == 0) 296 return; 297 298 if (bootp_packet_handler) { 299 ifrom.len = 4; 300 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len); 301 302 (*bootp_packet_handler)(ip, &u.packet, result, 303 from.sin_port, ifrom, &hfrom); 304 } 305} 306 307int 308interface_status(struct interface_info *ifinfo) 309{ 310 char *ifname = ifinfo->name; 311 int ifsock = ifinfo->rfdesc; 312 struct ifreq ifr; 313 struct ifmediareq ifmr; 314 315 /* get interface flags */ 316 memset(&ifr, 0, sizeof(ifr)); 317 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 318 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) { 319 syslog(LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", ifname); 320 goto inactive; 321 } 322 323 /* 324 * if one of UP and RUNNING flags is dropped, 325 * the interface is not active. 326 */ 327 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) 328 goto inactive; 329 330 /* Next, check carrier on the interface, if possible */ 331 if (ifinfo->noifmedia) 332 goto active; 333 memset(&ifmr, 0, sizeof(ifmr)); 334 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 335 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) { 336 if (errno != EINVAL) { 337 syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m", 338 ifname); 339 340 ifinfo->noifmedia = 1; 341 goto active; 342 } 343 /* 344 * EINVAL (or ENOTTY) simply means that the interface 345 * does not support the SIOCGIFMEDIA ioctl. We regard it alive. 346 */ 347 ifinfo->noifmedia = 1; 348 goto active; 349 } 350 if (ifmr.ifm_status & IFM_AVALID) { 351 switch (ifmr.ifm_active & IFM_NMASK) { 352 case IFM_ETHER: 353 case IFM_IEEE80211: 354 if (ifmr.ifm_status & IFM_ACTIVE) 355 goto active; 356 else 357 goto inactive; 358 break; 359 default: 360 goto inactive; 361 } 362 } 363inactive: 364 return (0); 365active: 366 return (1); 367} 368 369void 370add_timeout(time_t when, void (*where)(void *), void *what) 371{ 372 struct timeout *t, *q; 373 374 /* See if this timeout supersedes an existing timeout. */ 375 t = NULL; 376 for (q = timeouts; q; q = q->next) { 377 if (q->func == where && q->what == what) { 378 if (t) 379 t->next = q->next; 380 else 381 timeouts = q->next; 382 break; 383 } 384 t = q; 385 } 386 387 /* If we didn't supersede a timeout, allocate a timeout 388 structure now. */ 389 if (!q) { 390 if (free_timeouts) { 391 q = free_timeouts; 392 free_timeouts = q->next; 393 q->func = where; 394 q->what = what; 395 } else { 396 q = malloc(sizeof(struct timeout)); 397 if (!q) 398 error("Can't allocate timeout structure!"); 399 q->func = where; 400 q->what = what; 401 } 402 } 403 404 q->when = when; 405 406 /* Now sort this timeout into the timeout list. */ 407 408 /* Beginning of list? */ 409 if (!timeouts || timeouts->when > q->when) { 410 q->next = timeouts; 411 timeouts = q; 412 return; 413 } 414 415 /* Middle of list? */ 416 for (t = timeouts; t->next; t = t->next) { 417 if (t->next->when > q->when) { 418 q->next = t->next; 419 t->next = q; 420 return; 421 } 422 } 423 424 /* End of list. */ 425 t->next = q; 426 q->next = NULL; 427} 428 429void 430cancel_timeout(void (*where)(void *), void *what) 431{ 432 struct timeout *t, *q; 433 434 /* Look for this timeout on the list, and unlink it if we find it. */ 435 t = NULL; 436 for (q = timeouts; q; q = q->next) { 437 if (q->func == where && q->what == what) { 438 if (t) 439 t->next = q->next; 440 else 441 timeouts = q->next; 442 break; 443 } 444 t = q; 445 } 446 447 /* If we found the timeout, put it on the free list. */ 448 if (q) { 449 q->next = free_timeouts; 450 free_timeouts = q; 451 } 452} 453 454/* Add a protocol to the list of protocols... */ 455void 456add_protocol(const char *name, int fd, void (*handler)(struct protocol *), 457 void *local) 458{ 459 struct protocol *p; 460 461 p = malloc(sizeof(*p)); 462 if (!p) 463 error("can't allocate protocol struct for %s", name); 464 465 p->fd = fd; 466 p->handler = handler; 467 p->local = local; 468 p->next = protocols; 469 protocols = p; 470} 471 472void 473remove_protocol(struct protocol *proto) 474{ 475 struct protocol *p, *next; 476 477 for (p = protocols; p; p = next) { 478 next = p->next; 479 if (p == proto) { 480 protocols = p->next; 481 free(p); 482 } 483 } 484} 485 486int 487interface_link_status(char *ifname) 488{ 489 struct ifmediareq ifmr; 490 int sock; 491 492 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 493 error("Can't create socket"); 494 495 memset(&ifmr, 0, sizeof(ifmr)); 496 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 497 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) { 498 /* EINVAL -> link state unknown. treat as active */ 499 if (errno != EINVAL) 500 syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m", 501 ifname); 502 close(sock); 503 return (1); 504 } 505 close(sock); 506 507 if (ifmr.ifm_status & IFM_AVALID) { 508 switch (ifmr.ifm_active & IFM_NMASK) { 509 case IFM_ETHER: 510 case IFM_IEEE80211: 511 if (ifmr.ifm_status & IFM_ACTIVE) 512 return (1); 513 else 514 return (0); 515 } 516 } 517 return (1); 518} 519 520void 521interface_set_mtu_unpriv(int privfd, u_int16_t mtu) 522{ 523 struct imsg_hdr hdr; 524 struct buf *buf; 525 int errs = 0; 526 527 hdr.code = IMSG_SET_INTERFACE_MTU; 528 hdr.len = sizeof(hdr) + 529 sizeof(u_int16_t); 530 531 if ((buf = buf_open(hdr.len)) == NULL) 532 error("buf_open: %m"); 533 534 errs += buf_add(buf, &hdr, sizeof(hdr)); 535 errs += buf_add(buf, &mtu, sizeof(mtu)); 536 if (errs) 537 error("buf_add: %m"); 538 539 if (buf_close(privfd, buf) == -1) 540 error("buf_close: %m"); 541} 542 543void 544interface_set_mtu_priv(char *ifname, u_int16_t mtu) 545{ 546 struct ifreq ifr; 547 int sock; 548 u_int16_t old_mtu; 549 550 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 551 error("Can't create socket"); 552 553 memset(&ifr, 0, sizeof(ifr)); 554 old_mtu = 0; 555 556 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 557 558 if (ioctl(sock, SIOCGIFMTU, (caddr_t)&ifr) == -1) 559 warning("SIOCGIFMTU failed (%s): %s", ifname, 560 strerror(errno)); 561 else 562 old_mtu = ifr.ifr_mtu; 563 564 if (mtu != old_mtu) { 565 ifr.ifr_mtu = mtu; 566 567 if (ioctl(sock, SIOCSIFMTU, &ifr) == -1) 568 warning("SIOCSIFMTU failed (%d): %s", mtu, 569 strerror(errno)); 570 } 571 572 close(sock); 573} 574