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
60 static struct rt *routes;
61
62 static struct rt *
find_route(struct rt * rts,const struct rt * r,struct rt ** lrt,const struct rt * srt)63 find_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
85 static void
desc_route(const char * cmd,const struct rt * rt,const char * ifname)86 desc_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. */
108 int
route_deleted(const struct rt * rt)109 route_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
125 static int
n_route(struct rt * rt,const struct interface * iface)126 n_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
150 static int
c_route(struct rt * ort,struct rt * nrt,const struct interface * iface)151 c_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
172 static int
d_route(struct rt * rt,const struct interface * iface,int metric)173 d_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
184 static struct rt *
get_subnet_route(struct dhcp_message * dhcp)185 get_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
206 static struct rt *
add_subnet_route(struct rt * rt,const struct interface * iface)207 add_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
226 static struct rt *
get_routes(const struct interface * iface)227 get_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 assigned IP address. This differs from our notion of a host route
256 * where the gateway is the destination address, so we fix it. */
257 static struct rt *
massage_host_routes(struct rt * rt,const struct interface * iface)258 massage_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
269 static struct rt *
add_destination_route(struct rt * rt,const struct interface * iface)270 add_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. */
287 static struct rt *
add_router_host_route(struct rt * rt,const struct interface * ifp)288 add_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
337 void
build_routes(void)338 build_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
393 static int
delete_address(struct interface * iface)394 delete_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
415 int
configure(struct interface * iface)416 configure(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