1/* 2 * dhcpcd - DHCP client daemon 3 * Copyright (c) 2006-2010 Roy Marples <roy@marples.name> 4 * All rights reserved 5 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28#include <sys/stat.h> 29#include <sys/uio.h> 30#include <sys/wait.h> 31 32#include <netinet/in.h> 33#include <arpa/inet.h> 34 35#include <ctype.h> 36#include <errno.h> 37#include <signal.h> 38#include <stdlib.h> 39#include <string.h> 40#include <unistd.h> 41 42#include <rump/rump_syscalls.h> 43 44#include "common.h" 45#include "configure.h" 46#include "dhcp.h" 47#include "if-options.h" 48#include "net.h" 49 50/* Some systems have route metrics */ 51#ifndef HAVE_ROUTE_METRIC 52# ifdef __linux__ 53# define HAVE_ROUTE_METRIC 1 54# endif 55# ifndef HAVE_ROUTE_METRIC 56# define HAVE_ROUTE_METRIC 0 57# endif 58#endif 59 60static struct rt *routes; 61 62static struct rt * 63find_route(struct rt *rts, const struct rt *r, struct rt **lrt, 64 const struct rt *srt) 65{ 66 struct rt *rt; 67 68 if (lrt) 69 *lrt = NULL; 70 for (rt = rts; rt; rt = rt->next) { 71 if (rt->dest.s_addr == r->dest.s_addr && 72#if HAVE_ROUTE_METRIC 73 (srt || (!rt->iface || 74 rt->iface->metric == r->iface->metric)) && 75#endif 76 (!srt || srt != rt) && 77 rt->net.s_addr == r->net.s_addr) 78 return rt; 79 if (lrt) 80 *lrt = rt; 81 } 82 return NULL; 83} 84 85static void 86desc_route(const char *cmd, const struct rt *rt, const char *ifname) 87{ 88 char addr[sizeof("000.000.000.000") + 1]; 89 90 strlcpy(addr, inet_ntoa(rt->dest), sizeof(addr)); 91 if (rt->gate.s_addr == INADDR_ANY) 92 fprintf(stderr, "%s: %s route to %s/%d\n", ifname, cmd, 93 addr, inet_ntocidr(rt->net)); 94 else if (rt->gate.s_addr == rt->dest.s_addr && 95 rt->net.s_addr == INADDR_BROADCAST) 96 fprintf(stderr, "%s: %s host route to %s\n", ifname, cmd, 97 addr); 98 else if (rt->dest.s_addr == INADDR_ANY && rt->net.s_addr == INADDR_ANY) 99 fprintf(stderr, "%s: %s default route via %s\n", ifname, cmd, 100 inet_ntoa(rt->gate)); 101 else 102 fprintf(stderr, "%s: %s route to %s/%d via %s\n", ifname, cmd, 103 addr, inet_ntocidr(rt->net), inet_ntoa(rt->gate)); 104} 105 106/* If something other than dhcpcd removes a route, 107 * we need to remove it from our internal table. */ 108int 109route_deleted(const struct rt *rt) 110{ 111 struct rt *f, *l; 112 113 f = find_route(routes, rt, &l, NULL); 114 if (f == NULL) 115 return 0; 116 desc_route("removing", f, f->iface->name); 117 if (l) 118 l->next = f->next; 119 else 120 routes = f->next; 121 free(f); 122 return 1; 123} 124 125static int 126n_route(struct rt *rt, const struct interface *iface) 127{ 128 /* Don't set default routes if not asked to */ 129 if (rt->dest.s_addr == 0 && 130 rt->net.s_addr == 0 && 131 !(iface->state->options->options & DHCPCD_GATEWAY)) 132 return -1; 133 134 desc_route("adding", rt, iface->name); 135 if (!add_route(iface, &rt->dest, &rt->net, &rt->gate, iface->metric)) 136 return 0; 137 if (errno == EEXIST) { 138 /* Pretend we added the subnet route */ 139 if (rt->dest.s_addr == (iface->addr.s_addr & iface->net.s_addr) && 140 rt->net.s_addr == iface->net.s_addr && 141 rt->gate.s_addr == 0) 142 return 0; 143 else 144 return -1; 145 } 146 fprintf(stderr, "%s: add_route failed: %d\n", iface->name, errno); 147 return -1; 148} 149 150static int 151c_route(struct rt *ort, struct rt *nrt, const struct interface *iface) 152{ 153 /* Don't set default routes if not asked to */ 154 if (nrt->dest.s_addr == 0 && 155 nrt->net.s_addr == 0 && 156 !(iface->state->options->options & DHCPCD_GATEWAY)) 157 return -1; 158 159 desc_route("changing", nrt, iface->name); 160 /* We delete and add the route so that we can change metric. 161 * This also has the nice side effect of flushing ARP entries so 162 * we don't have to do that manually. */ 163 del_route(ort->iface, &ort->dest, &ort->net, &ort->gate, 164 ort->iface->metric); 165 if (!add_route(iface, &nrt->dest, &nrt->net, &nrt->gate, 166 iface->metric)) 167 return 0; 168 fprintf(stderr, "%s: add_route failed: %d\n", iface->name, errno); 169 return -1; 170} 171 172static int 173d_route(struct rt *rt, const struct interface *iface, int metric) 174{ 175 int retval; 176 177 desc_route("deleting", rt, iface->name); 178 retval = del_route(iface, &rt->dest, &rt->net, &rt->gate, metric); 179 if (retval != 0 && errno != ENOENT && errno != ESRCH) 180 fprintf(stderr,"%s: del_route: %d\n", iface->name, errno); 181 return retval; 182} 183 184static struct rt * 185get_subnet_route(struct dhcp_message *dhcp) 186{ 187 in_addr_t addr; 188 struct in_addr net; 189 struct rt *rt; 190 191 addr = dhcp->yiaddr; 192 if (addr == 0) 193 addr = dhcp->ciaddr; 194 /* Ensure we have all the needed values */ 195 if (get_option_addr(&net, dhcp, DHO_SUBNETMASK) == -1) 196 net.s_addr = get_netmask(addr); 197 if (net.s_addr == INADDR_BROADCAST || net.s_addr == INADDR_ANY) 198 return NULL; 199 rt = malloc(sizeof(*rt)); 200 rt->dest.s_addr = addr & net.s_addr; 201 rt->net.s_addr = net.s_addr; 202 rt->gate.s_addr = 0; 203 return rt; 204} 205 206static struct rt * 207add_subnet_route(struct rt *rt, const struct interface *iface) 208{ 209 struct rt *r; 210 211 if (iface->net.s_addr == INADDR_BROADCAST || 212 iface->net.s_addr == INADDR_ANY || 213 (iface->state->options->options & 214 (DHCPCD_INFORM | DHCPCD_STATIC) && 215 iface->state->options->req_addr.s_addr == INADDR_ANY)) 216 return rt; 217 218 r = xmalloc(sizeof(*r)); 219 r->dest.s_addr = iface->addr.s_addr & iface->net.s_addr; 220 r->net.s_addr = iface->net.s_addr; 221 r->gate.s_addr = 0; 222 r->next = rt; 223 return r; 224} 225 226static struct rt * 227get_routes(const struct interface *iface) 228{ 229 struct rt *rt, *nrt = NULL, *r = NULL; 230 231 if (iface->state->options->routes != NULL) { 232 for (rt = iface->state->options->routes; 233 rt != NULL; 234 rt = rt->next) 235 { 236 if (rt->gate.s_addr == 0) 237 break; 238 if (r == NULL) 239 r = nrt = xmalloc(sizeof(*r)); 240 else { 241 r->next = xmalloc(sizeof(*r)); 242 r = r->next; 243 } 244 memcpy(r, rt, sizeof(*r)); 245 r->next = NULL; 246 } 247 return nrt; 248 } 249 250 return get_option_routes(iface->state->new, 251 iface->name, &iface->state->options->options); 252} 253 254/* Some DHCP servers add set host routes by setting the gateway 255 * to the assinged IP address. This differs from our notion of a host route 256 * where the gateway is the destination address, so we fix it. */ 257static struct rt * 258massage_host_routes(struct rt *rt, const struct interface *iface) 259{ 260 struct rt *r; 261 262 for (r = rt; r; r = r->next) 263 if (r->gate.s_addr == iface->addr.s_addr && 264 r->net.s_addr == INADDR_BROADCAST) 265 r->gate.s_addr = r->dest.s_addr; 266 return rt; 267} 268 269static struct rt * 270add_destination_route(struct rt *rt, const struct interface *iface) 271{ 272 struct rt *r; 273 274 if (!(iface->flags & IFF_POINTOPOINT) || 275 !has_option_mask(iface->state->options->dstmask, DHO_ROUTER)) 276 return rt; 277 r = xmalloc(sizeof(*r)); 278 r->dest.s_addr = INADDR_ANY; 279 r->net.s_addr = INADDR_ANY; 280 r->gate.s_addr = iface->dst.s_addr; 281 r->next = rt; 282 return r; 283} 284 285/* We should check to ensure the routers are on the same subnet 286 * OR supply a host route. If not, warn and add a host route. */ 287static struct rt * 288add_router_host_route(struct rt *rt, const struct interface *ifp) 289{ 290 struct rt *rtp, *rtl, *rtn; 291 const char *cp, *cp2, *cp3, *cplim; 292 293 for (rtp = rt, rtl = NULL; rtp; rtl = rtp, rtp = rtp->next) { 294 if (rtp->dest.s_addr != INADDR_ANY) 295 continue; 296 /* Scan for a route to match */ 297 for (rtn = rt; rtn != rtp; rtn = rtn->next) { 298 /* match host */ 299 if (rtn->dest.s_addr == rtp->gate.s_addr) 300 break; 301 /* match subnet */ 302 cp = (const char *)&rtp->gate.s_addr; 303 cp2 = (const char *)&rtn->dest.s_addr; 304 cp3 = (const char *)&rtn->net.s_addr; 305 cplim = cp3 + sizeof(rtn->net.s_addr); 306 while (cp3 < cplim) { 307 if ((*cp++ ^ *cp2++) & *cp3++) 308 break; 309 } 310 if (cp3 == cplim) 311 break; 312 } 313 if (rtn != rtp) 314 continue; 315 if (ifp->flags & IFF_NOARP) { 316 fprintf(stderr, 317 "%s: forcing router %s through interface\n", 318 ifp->name, inet_ntoa(rtp->gate)); 319 rtp->gate.s_addr = 0; 320 continue; 321 } 322 fprintf(stderr, "%s: router %s requires a host route\n", 323 ifp->name, inet_ntoa(rtp->gate)); 324 rtn = xmalloc(sizeof(*rtn)); 325 rtn->dest.s_addr = rtp->gate.s_addr; 326 rtn->net.s_addr = INADDR_BROADCAST; 327 rtn->gate.s_addr = rtp->gate.s_addr; 328 rtn->next = rtp; 329 if (rtl == NULL) 330 rt = rtn; 331 else 332 rtl->next = rtn; 333 } 334 return rt; 335} 336 337void 338build_routes(void) 339{ 340 struct rt *nrs = NULL, *dnr, *or, *rt, *rtn, *rtl, *lrt = NULL; 341 const struct interface *ifp; 342 343 for (ifp = ifaces; ifp; ifp = ifp->next) { 344 if (ifp->state->new == NULL) 345 continue; 346 dnr = get_routes(ifp); 347 dnr = massage_host_routes(dnr, ifp); 348 dnr = add_subnet_route(dnr, ifp); 349 dnr = add_router_host_route(dnr, ifp); 350 dnr = add_destination_route(dnr, ifp); 351 for (rt = dnr; rt && (rtn = rt->next, 1); lrt = rt, rt = rtn) { 352 rt->iface = ifp; 353 /* Is this route already in our table? */ 354 if ((find_route(nrs, rt, NULL, NULL)) != NULL) 355 continue; 356 /* Do we already manage it? */ 357 if ((or = find_route(routes, rt, &rtl, NULL))) { 358 if (or->iface != ifp || 359 rt->gate.s_addr != or->gate.s_addr) 360 { 361 if (c_route(or, rt, ifp) != 0) 362 continue; 363 } 364 if (rtl != NULL) 365 rtl->next = or->next; 366 else 367 routes = or->next; 368 free(or); 369 } else { 370 if (n_route(rt, ifp) != 0) 371 continue; 372 } 373 if (dnr == rt) 374 dnr = rtn; 375 else if (lrt) 376 lrt->next = rtn; 377 rt->next = nrs; 378 nrs = rt; 379 } 380 free_routes(dnr); 381 } 382 383 /* Remove old routes we used to manage */ 384 for (rt = routes; rt; rt = rt->next) { 385 if (find_route(nrs, rt, NULL, NULL) == NULL) 386 d_route(rt, rt->iface, rt->iface->metric); 387 } 388 389 free_routes(routes); 390 routes = nrs; 391} 392 393static int 394delete_address(struct interface *iface) 395{ 396 int retval; 397 struct if_options *ifo; 398 399 ifo = iface->state->options; 400 if (ifo->options & DHCPCD_INFORM || 401 (ifo->options & DHCPCD_STATIC && ifo->req_addr.s_addr == 0)) 402 return 0; 403 fprintf(stderr, "%s: deleting IP address %s/%d\n", 404 iface->name, 405 inet_ntoa(iface->addr), 406 inet_ntocidr(iface->net)); 407 retval = del_address(iface, &iface->addr, &iface->net); 408 if (retval == -1 && errno != EADDRNOTAVAIL) 409 fprintf(stderr, "del_address failed: %d\n", errno); 410 iface->addr.s_addr = 0; 411 iface->net.s_addr = 0; 412 return retval; 413} 414 415int 416configure(struct interface *iface) 417{ 418 struct dhcp_message *dhcp = iface->state->new; 419 struct dhcp_lease *lease = &iface->state->lease; 420 struct if_options *ifo = iface->state->options; 421 struct rt *rt; 422 423 /* This also changes netmask */ 424 if (!(ifo->options & DHCPCD_INFORM) || 425 !has_address(iface->name, &lease->addr, &lease->net)) 426 { 427 fprintf(stderr, "%s: adding IP address %s/%d\n", 428 iface->name, inet_ntoa(lease->addr), 429 inet_ntocidr(lease->net)); 430 if (add_address(iface, 431 &lease->addr, &lease->net, &lease->brd) == -1 && 432 errno != EEXIST) 433 { 434 fprintf(stderr, "add_address failed\n"); 435 return -1; 436 } 437 } 438 439 /* Now delete the old address if different */ 440 if (iface->addr.s_addr != lease->addr.s_addr && 441 iface->addr.s_addr != 0) 442 delete_address(iface); 443 444 iface->addr.s_addr = lease->addr.s_addr; 445 iface->net.s_addr = lease->net.s_addr; 446 447 /* We need to delete the subnet route to have our metric or 448 * prefer the interface. */ 449 rt = get_subnet_route(dhcp); 450 if (rt != NULL) { 451 rt->iface = iface; 452 if (!find_route(routes, rt, NULL, NULL)) 453 del_route(iface, &rt->dest, &rt->net, &rt->gate, 0); 454 free(rt); 455 } 456 457 build_routes(); 458 459 fprintf(stderr, "lease time: "); 460 if (lease->leasetime == ~0U) 461 fprintf(stderr, "infinite\n"); 462 else 463 fprintf(stderr, "%u seconds (%.2f days)\n", 464 lease->leasetime, lease->leasetime / (60*60*24+.0)); 465 466 return 0; 467} 468