1 /* $OpenBSD: dispatch.c,v 1.9 2009/09/03 11:56:49 reyk 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 "dhcpd.h" 43 44 #include <sys/ioctl.h> 45 46 #include <net/if_media.h> 47 #include <net/if_types.h> 48 49 #include <ifaddrs.h> 50 #include <poll.h> 51 52 struct protocol *protocols; 53 struct timeout *timeouts; 54 static struct timeout *free_timeouts; 55 static int interfaces_invalidated; 56 57 void (*bootp_packet_handler)(struct interface_info *, 58 struct dhcp_packet *, int, unsigned int, 59 struct iaddr, struct hardware *); 60 61 static int interface_status(struct interface_info *ifinfo); 62 63 /* 64 * Use getifaddrs() to get a list of all the attached interfaces. For 65 * each interface that's of type INET and not the loopback interface, 66 * register that interface with the network I/O software, figure out 67 * what subnet it's on, and add it to the list of interfaces. 68 */ 69 void 70 discover_interfaces(struct interface_info *iface) 71 { 72 struct sockaddr_in foo; 73 struct ifaddrs *ifap, *ifa; 74 struct ifreq *tif; 75 76 if (getifaddrs(&ifap) != 0) 77 error("getifaddrs failed"); 78 79 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 80 if ((ifa->ifa_flags & IFF_LOOPBACK) || 81 (ifa->ifa_flags & IFF_POINTOPOINT) || 82 (!(ifa->ifa_flags & IFF_UP))) 83 continue; 84 85 if (strcmp(iface->name, ifa->ifa_name)) 86 continue; 87 88 /* 89 * If we have the capability, extract link information 90 * and record it in a linked list. 91 */ 92 if (ifa->ifa_addr->sa_family == AF_LINK) { 93 struct sockaddr_dl *foo = 94 (struct sockaddr_dl *)ifa->ifa_addr; 95 struct if_data *ifi = 96 (struct if_data *)ifa->ifa_data; 97 98 iface->index = foo->sdl_index; 99 iface->hw_address.hlen = foo->sdl_alen; 100 if (ifi->ifi_type == IFT_ENC) 101 iface->hw_address.htype = HTYPE_IPSEC_TUNNEL; 102 else 103 iface->hw_address.htype = HTYPE_ETHER; /* XXX */ 104 memcpy(iface->hw_address.haddr, 105 LLADDR(foo), foo->sdl_alen); 106 } else if (ifa->ifa_addr->sa_family == AF_INET) { 107 struct iaddr addr; 108 109 memcpy(&foo, ifa->ifa_addr, sizeof(foo)); 110 if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK)) 111 continue; 112 if (!iface->ifp) { 113 int len = IFNAMSIZ + ifa->ifa_addr->sa_len; 114 115 if ((tif = malloc(len)) == NULL) 116 error("no space to remember ifp"); 117 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ); 118 memcpy(&tif->ifr_addr, ifa->ifa_addr, 119 ifa->ifa_addr->sa_len); 120 iface->ifp = tif; 121 iface->primary_address = foo.sin_addr; 122 } 123 addr.len = 4; 124 memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len); 125 } 126 } 127 128 if (!iface->ifp) 129 error("%s: not found", iface->name); 130 131 /* Register the interface... */ 132 if_register_receive(iface); 133 if_register_send(iface); 134 add_protocol(iface->name, iface->rfdesc, got_one, iface); 135 freeifaddrs(ifap); 136 } 137 138 /* 139 * Wait for packets to come in using poll(). When a packet comes in, 140 * call receive_packet to receive the packet and possibly strip hardware 141 * addressing information from it, and then call through the 142 * bootp_packet_handler hook to try to do something with it. 143 */ 144 void 145 dispatch(void) 146 { 147 int count, i, to_msec, nfds = 0; 148 struct protocol *l; 149 struct pollfd *fds; 150 time_t howlong; 151 152 nfds = 0; 153 for (l = protocols; l; l = l->next) 154 nfds++; 155 156 fds = calloc(nfds, sizeof(struct pollfd)); 157 if (fds == NULL) 158 error("Can't allocate poll structures."); 159 160 do { 161 /* 162 * Call any expired timeouts, and then if there's still 163 * a timeout registered, time out the select call then. 164 */ 165 another: 166 if (timeouts) { 167 if (timeouts->when <= cur_time) { 168 struct timeout *t = timeouts; 169 170 timeouts = timeouts->next; 171 (*(t->func))(t->what); 172 t->next = free_timeouts; 173 free_timeouts = t; 174 goto another; 175 } 176 177 /* 178 * Figure timeout in milliseconds, and check for 179 * potential overflow, so we can cram into an 180 * int for poll, while not polling with a 181 * negative timeout and blocking indefinitely. 182 */ 183 howlong = timeouts->when - cur_time; 184 if (howlong > INT_MAX / 1000) 185 howlong = INT_MAX / 1000; 186 to_msec = howlong * 1000; 187 } else 188 to_msec = -1; 189 190 /* Set up the descriptors to be polled. */ 191 i = 0; 192 193 for (l = protocols; l; l = l->next) { 194 struct interface_info *ip = l->local; 195 196 if (ip && (l->handler != got_one || !ip->dead)) { 197 fds[i].fd = l->fd; 198 fds[i].events = POLLIN; 199 fds[i].revents = 0; 200 i++; 201 } 202 } 203 204 if (i == 0) 205 error("No live interfaces to poll on - exiting."); 206 207 /* Wait for a packet or a timeout... XXX */ 208 count = poll(fds, nfds, to_msec); 209 210 /* Not likely to be transitory... */ 211 if (count == -1) { 212 if (errno == EAGAIN || errno == EINTR) { 213 time(&cur_time); 214 continue; 215 } 216 else 217 error("poll: %m"); 218 } 219 220 /* Get the current time... */ 221 time(&cur_time); 222 223 i = 0; 224 for (l = protocols; l; l = l->next) { 225 struct interface_info *ip = l->local; 226 227 if ((fds[i].revents & (POLLIN | POLLHUP))) { 228 fds[i].revents = 0; 229 if (ip && (l->handler != got_one || 230 !ip->dead)) 231 (*(l->handler))(l); 232 if (interfaces_invalidated) 233 break; 234 } 235 i++; 236 } 237 interfaces_invalidated = 0; 238 } while (1); 239 } 240 241 242 void 243 got_one(struct protocol *l) 244 { 245 struct sockaddr_in from; 246 struct hardware hfrom; 247 struct iaddr ifrom; 248 size_t result; 249 union { 250 /* 251 * Packet input buffer. Must be as large as largest 252 * possible MTU. 253 */ 254 unsigned char packbuf[4095]; 255 struct dhcp_packet packet; 256 } u; 257 struct interface_info *ip = l->local; 258 259 if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from, 260 &hfrom)) == -1) { 261 warning("receive_packet failed on %s: %s", ip->name, 262 strerror(errno)); 263 ip->errors++; 264 if ((!interface_status(ip)) || 265 (ip->noifmedia && ip->errors > 20)) { 266 /* our interface has gone away. */ 267 warning("Interface %s no longer appears valid.", 268 ip->name); 269 ip->dead = 1; 270 interfaces_invalidated = 1; 271 close(l->fd); 272 remove_protocol(l); 273 free(ip); 274 } 275 return; 276 } 277 if (result == 0) 278 return; 279 280 if (bootp_packet_handler) { 281 ifrom.len = 4; 282 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len); 283 284 (*bootp_packet_handler)(ip, &u.packet, result, 285 from.sin_port, ifrom, &hfrom); 286 } 287 } 288 289 int 290 interface_status(struct interface_info *ifinfo) 291 { 292 char *ifname = ifinfo->name; 293 int ifsock = ifinfo->rfdesc; 294 struct ifreq ifr; 295 struct ifmediareq ifmr; 296 297 /* get interface flags */ 298 memset(&ifr, 0, sizeof(ifr)); 299 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 300 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) == -1) { 301 syslog(LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", ifname); 302 goto inactive; 303 } 304 /* 305 * if one of UP and RUNNING flags is dropped, 306 * the interface is not active. 307 */ 308 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) { 309 goto inactive; 310 } 311 /* Next, check carrier on the interface, if possible */ 312 if (ifinfo->noifmedia) 313 goto active; 314 memset(&ifmr, 0, sizeof(ifmr)); 315 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 316 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) { 317 if (errno != EINVAL) { 318 syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m", 319 ifname); 320 321 ifinfo->noifmedia = 1; 322 goto active; 323 } 324 /* 325 * EINVAL (or ENOTTY) simply means that the interface 326 * does not support the SIOCGIFMEDIA ioctl. We regard it alive. 327 */ 328 ifinfo->noifmedia = 1; 329 goto active; 330 } 331 if (ifmr.ifm_status & IFM_AVALID) { 332 switch (ifmr.ifm_active & IFM_NMASK) { 333 case IFM_ETHER: 334 if (ifmr.ifm_status & IFM_ACTIVE) 335 goto active; 336 else 337 goto inactive; 338 break; 339 default: 340 goto inactive; 341 } 342 } 343 inactive: 344 return (0); 345 active: 346 return (1); 347 } 348 349 /* Add a protocol to the list of protocols... */ 350 void 351 add_protocol(char *name, int fd, void (*handler)(struct protocol *), 352 void *local) 353 { 354 struct protocol *p; 355 356 p = malloc(sizeof(*p)); 357 if (!p) 358 error("can't allocate protocol struct for %s", name); 359 360 p->fd = fd; 361 p->handler = handler; 362 p->local = local; 363 p->next = protocols; 364 protocols = p; 365 } 366 367 void 368 remove_protocol(struct protocol *proto) 369 { 370 struct protocol *p, *next, *prev; 371 372 prev = NULL; 373 for (p = protocols; p; p = next) { 374 next = p->next; 375 if (p == proto) { 376 if (prev) 377 prev->next = p->next; 378 else 379 protocols = p->next; 380 free(p); 381 } 382 } 383 } 384