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      1 /*
      2  * dhcpcd - DHCP client daemon
      3  * Copyright (c) 2006-2015 Roy Marples <roy (at) 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/socket.h>
     29 #include <sys/types.h>
     30 
     31 #include <netinet/in.h>
     32 #include <arpa/inet.h>
     33 #include <net/route.h>
     34 
     35 #include <ctype.h>
     36 #include <errno.h>
     37 #include <stdlib.h>
     38 #include <string.h>
     39 #include <unistd.h>
     40 
     41 #include "config.h"
     42 #include "arp.h"
     43 #include "common.h"
     44 #include "dhcpcd.h"
     45 #include "dhcp.h"
     46 #include "if.h"
     47 #include "if-options.h"
     48 #include "ipv4.h"
     49 #include "script.h"
     50 #ifdef PASSIVE_MODE
     51 #include "rpc-interface.h"
     52 #endif
     53 
     54 #define IPV4_LOOPBACK_ROUTE
     55 #if defined(__linux__) || (defined(BSD) && defined(RTF_LOCAL))
     56 /* Linux has had loopback routes in the local table since 2.2 */
     57 #undef IPV4_LOOPBACK_ROUTE
     58 #endif
     59 
     60 uint8_t
     61 inet_ntocidr(struct in_addr address)
     62 {
     63 	uint8_t cidr = 0;
     64 	uint32_t mask = htonl(address.s_addr);
     65 
     66 	while (mask) {
     67 		cidr++;
     68 		mask <<= 1;
     69 	}
     70 	return cidr;
     71 }
     72 
     73 int
     74 inet_cidrtoaddr(int cidr, struct in_addr *addr)
     75 {
     76 	int ocets;
     77 
     78 	if (cidr < 1 || cidr > 32) {
     79 		errno = EINVAL;
     80 		return -1;
     81 	}
     82 	ocets = (cidr + 7) / NBBY;
     83 
     84 	addr->s_addr = 0;
     85 	if (ocets > 0) {
     86 		memset(&addr->s_addr, 255, (size_t)ocets - 1);
     87 		memset((unsigned char *)&addr->s_addr + (ocets - 1),
     88 		    (256 - (1 << (32 - cidr) % NBBY)), 1);
     89 	}
     90 
     91 	return 0;
     92 }
     93 
     94 uint32_t
     95 ipv4_getnetmask(uint32_t addr)
     96 {
     97 	uint32_t dst;
     98 
     99 	if (addr == 0)
    100 		return 0;
    101 
    102 	dst = htonl(addr);
    103 	if (IN_CLASSA(dst))
    104 		return ntohl(IN_CLASSA_NET);
    105 	if (IN_CLASSB(dst))
    106 		return ntohl(IN_CLASSB_NET);
    107 	if (IN_CLASSC(dst))
    108 		return ntohl(IN_CLASSC_NET);
    109 
    110 	return 0;
    111 }
    112 
    113 struct ipv4_addr *
    114 ipv4_iffindaddr(struct interface *ifp,
    115     const struct in_addr *addr, const struct in_addr *net)
    116 {
    117 	struct ipv4_state *state;
    118 	struct ipv4_addr *ap;
    119 
    120 	state = IPV4_STATE(ifp);
    121 	if (state) {
    122 		TAILQ_FOREACH(ap, &state->addrs, next) {
    123 			if ((addr == NULL || ap->addr.s_addr == addr->s_addr) &&
    124 			    (net == NULL || ap->net.s_addr == net->s_addr))
    125 				return ap;
    126 		}
    127 	}
    128 	return NULL;
    129 }
    130 
    131 struct ipv4_addr *
    132 ipv4_iffindlladdr(struct interface *ifp)
    133 {
    134 	struct ipv4_state *state;
    135 	struct ipv4_addr *ap;
    136 
    137 	state = IPV4_STATE(ifp);
    138 	if (state) {
    139 		TAILQ_FOREACH(ap, &state->addrs, next) {
    140 			if (IN_LINKLOCAL(htonl(ap->addr.s_addr)))
    141 				return ap;
    142 		}
    143 	}
    144 	return NULL;
    145 }
    146 
    147 struct ipv4_addr *
    148 ipv4_findaddr(struct dhcpcd_ctx *ctx, const struct in_addr *addr)
    149 {
    150 	struct interface *ifp;
    151 	struct ipv4_addr *ap;
    152 
    153 	TAILQ_FOREACH(ifp, ctx->ifaces, next) {
    154 		ap = ipv4_iffindaddr(ifp, addr, NULL);
    155 		if (ap)
    156 			return ap;
    157 	}
    158 	return NULL;
    159 }
    160 
    161 int
    162 ipv4_addrexists(struct dhcpcd_ctx *ctx, const struct in_addr *addr)
    163 {
    164 	struct interface *ifp;
    165 	struct dhcp_state *state;
    166 
    167 	TAILQ_FOREACH(ifp, ctx->ifaces, next) {
    168 		state = D_STATE(ifp);
    169 		if (state) {
    170 			if (addr == NULL) {
    171 				if (state->addr.s_addr != INADDR_ANY)
    172 					return 1;
    173 			} else if (addr->s_addr == state->addr.s_addr)
    174 				return 1;
    175 		}
    176 		if (addr != NULL && ipv4_iffindaddr(ifp, addr, NULL))
    177 			return 1;
    178 	}
    179 	return 0;
    180 }
    181 
    182 void
    183 ipv4_freeroutes(struct rt_head *rts)
    184 {
    185 
    186 	if (rts) {
    187 		ipv4_freerts(rts);
    188 		free(rts);
    189 	}
    190 }
    191 
    192 int
    193 ipv4_init(struct dhcpcd_ctx *ctx)
    194 {
    195 
    196 	if (ctx->ipv4_routes == NULL) {
    197 		ctx->ipv4_routes = malloc(sizeof(*ctx->ipv4_routes));
    198 		if (ctx->ipv4_routes == NULL)
    199 			return -1;
    200 		TAILQ_INIT(ctx->ipv4_routes);
    201 	}
    202 	if (ctx->ipv4_kroutes == NULL) {
    203 		ctx->ipv4_kroutes = malloc(sizeof(*ctx->ipv4_kroutes));
    204 		if (ctx->ipv4_kroutes == NULL)
    205 			return -1;
    206 		TAILQ_INIT(ctx->ipv4_kroutes);
    207 	}
    208 	return 0;
    209 }
    210 
    211 /* Interface comparer for working out ordering. */
    212 int
    213 ipv4_ifcmp(const struct interface *si, const struct interface *ti)
    214 {
    215 	const struct dhcp_state *sis, *tis;
    216 
    217 	sis = D_CSTATE(si);
    218 	tis = D_CSTATE(ti);
    219 	if (sis && !tis)
    220 		return -1;
    221 	if (!sis && tis)
    222 		return 1;
    223 	if (!sis && !tis)
    224 		return 0;
    225 	/* If one has a lease and the other not, it takes precedence. */
    226 	if (sis->new && !tis->new)
    227 		return -1;
    228 	if (!sis->new && tis->new)
    229 		return 1;
    230 	/* Always prefer proper leases */
    231 	if (!(sis->added & STATE_FAKE) && (sis->added & STATE_FAKE))
    232 		return -1;
    233 	if ((sis->added & STATE_FAKE) && !(sis->added & STATE_FAKE))
    234 		return 1;
    235 	/* If we are either, they neither have a lease, or they both have.
    236 	 * We need to check for IPv4LL and make it non-preferred. */
    237 	if (sis->new && tis->new) {
    238 		int sill = (sis->new->cookie == htonl(MAGIC_COOKIE));
    239 		int till = (tis->new->cookie == htonl(MAGIC_COOKIE));
    240 		if (sill && !till)
    241 			return -1;
    242 		if (!sill && till)
    243 			return 1;
    244 	}
    245 	return 0;
    246 }
    247 
    248 static struct rt *
    249 find_route(struct rt_head *rts, const struct rt *r, const struct rt *srt)
    250 {
    251 	struct rt *rt;
    252 
    253 	if (rts == NULL)
    254 		return NULL;
    255 	TAILQ_FOREACH(rt, rts, next) {
    256 		if (rt->dest.s_addr == r->dest.s_addr &&
    257 #ifdef HAVE_ROUTE_METRIC
    258 		    (srt || (r->iface == NULL || rt->iface == NULL ||
    259 		    rt->iface->metric == r->iface->metric)) &&
    260 #endif
    261                     (!srt || srt != rt) &&
    262 		    rt->net.s_addr == r->net.s_addr)
    263 			return rt;
    264 	}
    265 	return NULL;
    266 }
    267 
    268 static void
    269 desc_route(const char *cmd, const struct rt *rt)
    270 {
    271 	char addr[sizeof("000.000.000.000") + 1];
    272 	struct dhcpcd_ctx *ctx = rt->iface ? rt->iface->ctx : NULL;
    273 	const char *ifname = rt->iface ? rt->iface->name : NULL;
    274 
    275 	strlcpy(addr, inet_ntoa(rt->dest), sizeof(addr));
    276 	if (rt->net.s_addr == htonl(INADDR_BROADCAST) &&
    277 	    rt->gate.s_addr == htonl(INADDR_ANY))
    278 		logger(ctx, LOG_INFO, "%s: %s host route to %s",
    279 		    ifname, cmd, addr);
    280 	else if (rt->net.s_addr == htonl(INADDR_BROADCAST))
    281 		logger(ctx, LOG_INFO, "%s: %s host route to %s via %s",
    282 		    ifname, cmd, addr, inet_ntoa(rt->gate));
    283 	else if (rt->gate.s_addr == htonl(INADDR_ANY))
    284 		logger(ctx, LOG_INFO, "%s: %s route to %s/%d",
    285 		    ifname, cmd, addr, inet_ntocidr(rt->net));
    286 	else if (rt->dest.s_addr == htonl(INADDR_ANY) &&
    287 	    rt->net.s_addr == htonl(INADDR_ANY))
    288 		logger(ctx, LOG_INFO, "%s: %s default route via %s",
    289 		    ifname, cmd, inet_ntoa(rt->gate));
    290 	else
    291 		logger(ctx, LOG_INFO, "%s: %s route to %s/%d via %s",
    292 		    ifname, cmd, addr, inet_ntocidr(rt->net),
    293 		    inet_ntoa(rt->gate));
    294 }
    295 
    296 static struct rt *
    297 ipv4_findrt(struct dhcpcd_ctx *ctx, const struct rt *rt, int flags)
    298 {
    299 	struct rt *r;
    300 
    301 	if (ctx->ipv4_kroutes == NULL)
    302 		return NULL;
    303 	TAILQ_FOREACH(r, ctx->ipv4_kroutes, next) {
    304 		if (rt->dest.s_addr == r->dest.s_addr &&
    305 #ifdef HAVE_ROUTE_METRIC
    306 		    rt->iface == r->iface &&
    307 		    (!flags || rt->metric == r->metric) &&
    308 #else
    309 		    (!flags || rt->iface == r->iface) &&
    310 #endif
    311 		    rt->net.s_addr == r->net.s_addr)
    312 			return r;
    313 	}
    314 	return NULL;
    315 }
    316 
    317 void
    318 ipv4_freerts(struct rt_head *routes)
    319 {
    320 	struct rt *rt;
    321 
    322 	while ((rt = TAILQ_FIRST(routes))) {
    323 		TAILQ_REMOVE(routes, rt, next);
    324 		free(rt);
    325 	}
    326 }
    327 
    328 /* If something other than dhcpcd removes a route,
    329  * we need to remove it from our internal table. */
    330 int
    331 ipv4_handlert(struct dhcpcd_ctx *ctx, int cmd, struct rt *rt)
    332 {
    333 	struct rt *f;
    334 
    335 	if (ctx->ipv4_kroutes == NULL)
    336 		return 0;
    337 
    338 	f = ipv4_findrt(ctx, rt, 1);
    339 	switch (cmd) {
    340 	case RTM_ADD:
    341 		if (f == NULL) {
    342 			if ((f = malloc(sizeof(*f))) == NULL)
    343 				return -1;
    344 			*f = *rt;
    345 			TAILQ_INSERT_TAIL(ctx->ipv4_kroutes, f, next);
    346 		}
    347 		break;
    348 	case RTM_DELETE:
    349 		if (f) {
    350 			TAILQ_REMOVE(ctx->ipv4_kroutes, f, next);
    351 			free(f);
    352 		}
    353 
    354 		/* If we manage the route, remove it */
    355 		if ((f = find_route(ctx->ipv4_routes, rt, NULL))) {
    356 			desc_route("removing", f);
    357 			TAILQ_REMOVE(ctx->ipv4_routes, f, next);
    358 			free(f);
    359 		}
    360 		break;
    361 	}
    362 	return 0;
    363 }
    364 
    365 #define n_route(a)	 nc_route(NULL, a)
    366 #define c_route(a, b)	 nc_route(a, b)
    367 static int
    368 nc_route(struct rt *ort, struct rt *nrt)
    369 {
    370 
    371 	/* Don't set default routes if not asked to */
    372 	if (nrt->dest.s_addr == 0 &&
    373 	    nrt->net.s_addr == 0 &&
    374 	    !(nrt->iface->options->options & DHCPCD_GATEWAY))
    375 		return -1;
    376 
    377 	desc_route(ort == NULL ? "adding" : "changing", nrt);
    378 
    379 	if (ort == NULL) {
    380 		ort = ipv4_findrt(nrt->iface->ctx, nrt, 0);
    381 		if (ort &&
    382 		    ((ort->flags & RTF_REJECT && nrt->flags & RTF_REJECT) ||
    383 		     (ort->iface == nrt->iface &&
    384 #ifdef HAVE_ROUTE_METRIC
    385 		    ort->metric == nrt->metric &&
    386 #endif
    387 		    ort->gate.s_addr == nrt->gate.s_addr)))
    388 			return 0;
    389 	} else if (ort->flags & STATE_FAKE && !(nrt->flags & STATE_FAKE) &&
    390 	    ort->iface == nrt->iface &&
    391 #ifdef HAVE_ROUTE_METRIC
    392 	    ort->metric == nrt->metric &&
    393 #endif
    394 	    ort->dest.s_addr == nrt->dest.s_addr &&
    395 	    ort->net.s_addr ==  nrt->net.s_addr &&
    396 	    ort->gate.s_addr == nrt->gate.s_addr)
    397 		return 0;
    398 
    399 #ifdef HAVE_ROUTE_METRIC
    400 	/* With route metrics, we can safely add the new route before
    401 	 * deleting the old route. */
    402 	if (if_route(RTM_ADD, nrt)  == 0) {
    403 		if (ort && if_route(RTM_DELETE, ort) == -1 && errno != ESRCH)
    404 			logger(nrt->iface->ctx, LOG_ERR, "if_route (DEL): %m");
    405 		return 0;
    406 	}
    407 
    408 	/* If the kernel claims the route exists we need to rip out the
    409 	 * old one first. */
    410 	if (errno != EEXIST || ort == NULL)
    411 		goto logerr;
    412 #endif
    413 
    414 	/* No route metrics, we need to delete the old route before
    415 	 * adding the new one. */
    416 	if (ort && if_route(RTM_DELETE, ort) == -1 && errno != ESRCH)
    417 		logger(nrt->iface->ctx, LOG_ERR, "if_route (DEL): %m");
    418 	if (if_route(RTM_ADD, nrt) == 0)
    419 		return 0;
    420 #ifdef HAVE_ROUTE_METRIC
    421 logerr:
    422 #endif
    423 	logger(nrt->iface->ctx, LOG_ERR, "if_route (ADD): %m");
    424 	return -1;
    425 }
    426 
    427 static int
    428 d_route(struct rt *rt)
    429 {
    430 	int retval;
    431 
    432 	desc_route("deleting", rt);
    433 	retval = if_route(RTM_DELETE, rt);
    434 	if (retval != 0 && errno != ENOENT && errno != ESRCH)
    435 		logger(rt->iface->ctx, LOG_ERR,
    436 		    "%s: if_delroute: %m", rt->iface->name);
    437 	return retval;
    438 }
    439 
    440 static struct rt_head *
    441 add_subnet_route(struct rt_head *rt, const struct interface *ifp)
    442 {
    443 	const struct dhcp_state *s;
    444 	struct rt *r;
    445 
    446 	if (rt == NULL) /* earlier malloc failed */
    447 		return NULL;
    448 
    449 	s = D_CSTATE(ifp);
    450 	/* Don't create a subnet route for these addresses */
    451 	if (s->net.s_addr == INADDR_ANY)
    452 		return rt;
    453 #ifndef BSD
    454 	/* BSD adds a route in this instance */
    455 	if (s->net.s_addr == INADDR_BROADCAST)
    456 		return rt;
    457 #endif
    458 
    459 	if ((r = malloc(sizeof(*r))) == NULL) {
    460 		logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
    461 		ipv4_freeroutes(rt);
    462 		return NULL;
    463 	}
    464 	r->dest.s_addr = s->addr.s_addr & s->net.s_addr;
    465 	r->net.s_addr = s->net.s_addr;
    466 	r->gate.s_addr = INADDR_ANY;
    467 
    468 	TAILQ_INSERT_HEAD(rt, r, next);
    469 	return rt;
    470 }
    471 
    472 #ifdef IPV4_LOOPBACK_ROUTE
    473 static struct rt_head *
    474 add_loopback_route(struct rt_head *rt, const struct interface *ifp)
    475 {
    476 	struct rt *r;
    477 	const struct dhcp_state *s;
    478 
    479 	if (rt == NULL) /* earlier malloc failed */
    480 		return NULL;
    481 
    482 	s = D_CSTATE(ifp);
    483 	if (s->addr.s_addr == INADDR_ANY)
    484 		return rt;
    485 
    486 	r = malloc(sizeof(*r));
    487 	if (r == NULL) {
    488 		logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
    489 		ipv4_freeroutes(rt);
    490 		return NULL;
    491 	}
    492 	r->dest.s_addr = s->addr.s_addr;
    493 	r->net.s_addr = INADDR_BROADCAST;
    494 	r->gate.s_addr = htonl(INADDR_LOOPBACK);
    495 	TAILQ_INSERT_HEAD(rt, r, next);
    496 	return rt;
    497 }
    498 #endif
    499 
    500 static struct rt_head *
    501 get_routes(struct interface *ifp)
    502 {
    503 	struct rt_head *nrt;
    504 	struct rt *rt, *r = NULL;
    505 
    506 	if (ifp->options->routes && TAILQ_FIRST(ifp->options->routes)) {
    507 		nrt = malloc(sizeof(*nrt));
    508 		TAILQ_INIT(nrt);
    509 		TAILQ_FOREACH(rt, ifp->options->routes, next) {
    510 			if (rt->gate.s_addr == 0)
    511 				break;
    512 			r = malloc(sizeof(*r));
    513 			if (r == NULL) {
    514 				logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
    515 				ipv4_freeroutes(nrt);
    516 				return NULL;
    517 			}
    518 			memcpy(r, rt, sizeof(*r));
    519 			TAILQ_INSERT_TAIL(nrt, r, next);
    520 		}
    521 		return nrt;
    522 	}
    523 
    524 	return get_option_routes(ifp, D_STATE(ifp)->new);
    525 }
    526 
    527 /* Some DHCP servers add set host routes by setting the gateway
    528  * to the assigned IP address or the destination address.
    529  * We need to change this. */
    530 static struct rt_head *
    531 massage_host_routes(struct rt_head *rt, const struct interface *ifp)
    532 {
    533 	struct rt *r;
    534 
    535 	if (rt) {
    536 		TAILQ_FOREACH(r, rt, next) {
    537 			if (r->gate.s_addr == D_CSTATE(ifp)->addr.s_addr ||
    538 			    r->gate.s_addr == r->dest.s_addr)
    539 			{
    540 				r->gate.s_addr = htonl(INADDR_ANY);
    541 				r->net.s_addr = htonl(INADDR_BROADCAST);
    542 			}
    543 		}
    544 	}
    545 	return rt;
    546 }
    547 
    548 
    549 static struct rt_head *
    550 add_destination_route(struct rt_head *rt, const struct interface *ifp)
    551 {
    552 	struct rt *r;
    553 
    554 	if (rt == NULL || /* failed a malloc earlier probably */
    555 	    !(ifp->flags & IFF_POINTOPOINT) ||
    556 	    !has_option_mask(ifp->options->dstmask, DHO_ROUTER))
    557 		return rt;
    558 
    559 	r = malloc(sizeof(*r));
    560 	if (r == NULL) {
    561 		logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
    562 		ipv4_freeroutes(rt);
    563 		return NULL;
    564 	}
    565 	r->dest.s_addr = INADDR_ANY;
    566 	r->net.s_addr = INADDR_ANY;
    567 	r->gate.s_addr = D_CSTATE(ifp)->dst.s_addr;
    568 	TAILQ_INSERT_HEAD(rt, r, next);
    569 	return rt;
    570 }
    571 
    572 /* We should check to ensure the routers are on the same subnet
    573  * OR supply a host route. If not, warn and add a host route. */
    574 static struct rt_head *
    575 add_router_host_route(struct rt_head *rt, const struct interface *ifp)
    576 {
    577 	struct rt *rtp, *rtn;
    578 	const char *cp, *cp2, *cp3, *cplim;
    579 	struct if_options *ifo;
    580 	const struct dhcp_state *state;
    581 
    582 	if (rt == NULL) /* earlier malloc failed */
    583 		return NULL;
    584 
    585 	TAILQ_FOREACH(rtp, rt, next) {
    586 		if (rtp->dest.s_addr != INADDR_ANY)
    587 			continue;
    588 		/* Scan for a route to match */
    589 		TAILQ_FOREACH(rtn, rt, next) {
    590 			if (rtn == rtp)
    591 				break;
    592 			/* match host */
    593 			if (rtn->dest.s_addr == rtp->gate.s_addr)
    594 				break;
    595 			/* match subnet */
    596 			cp = (const char *)&rtp->gate.s_addr;
    597 			cp2 = (const char *)&rtn->dest.s_addr;
    598 			cp3 = (const char *)&rtn->net.s_addr;
    599 			cplim = cp3 + sizeof(rtn->net.s_addr);
    600 			while (cp3 < cplim) {
    601 				if ((*cp++ ^ *cp2++) & *cp3++)
    602 					break;
    603 			}
    604 			if (cp3 == cplim)
    605 				break;
    606 		}
    607 		if (rtn != rtp)
    608 			continue;
    609 		state = D_CSTATE(ifp);
    610 		ifo = ifp->options;
    611 		if (ifp->flags & IFF_NOARP) {
    612 			if (!(ifo->options & DHCPCD_ROUTER_HOST_ROUTE_WARNED) &&
    613 			    !(state->added & STATE_FAKE))
    614 			{
    615 				ifo->options |= DHCPCD_ROUTER_HOST_ROUTE_WARNED;
    616 				logger(ifp->ctx, LOG_WARNING,
    617 				    "%s: forcing router %s through interface",
    618 				    ifp->name, inet_ntoa(rtp->gate));
    619 			}
    620 			rtp->gate.s_addr = 0;
    621 			continue;
    622 		}
    623 		if (!(ifo->options & DHCPCD_ROUTER_HOST_ROUTE_WARNED) &&
    624 		    !(state->added & STATE_FAKE))
    625 		{
    626 			ifo->options |= DHCPCD_ROUTER_HOST_ROUTE_WARNED;
    627 			logger(ifp->ctx, LOG_WARNING,
    628 			    "%s: router %s requires a host route",
    629 			    ifp->name, inet_ntoa(rtp->gate));
    630 		}
    631 		rtn = malloc(sizeof(*rtn));
    632 		if (rtn == NULL) {
    633 			logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
    634 			ipv4_freeroutes(rt);
    635 			return NULL;
    636 		}
    637 		rtn->dest.s_addr = rtp->gate.s_addr;
    638 		rtn->net.s_addr = htonl(INADDR_BROADCAST);
    639 		rtn->gate.s_addr = htonl(INADDR_ANY);
    640 		TAILQ_INSERT_BEFORE(rtp, rtn, next);
    641 	}
    642 	return rt;
    643 }
    644 
    645 void
    646 ipv4_buildroutes(struct dhcpcd_ctx *ctx)
    647 {
    648 /* Do not modify route table when running in passive mode. */
    649 #ifndef PASSIVE_MODE
    650 	struct rt_head *nrs, *dnr;
    651 	struct rt *or, *rt, *rtn;
    652 	struct interface *ifp;
    653 	const struct dhcp_state *state;
    654 
    655 	/* We need to have the interfaces in the correct order to ensure
    656 	 * our routes are managed correctly. */
    657 	if_sortinterfaces(ctx);
    658 
    659 	nrs = malloc(sizeof(*nrs));
    660 	if (nrs == NULL) {
    661 		logger(ctx, LOG_ERR, "%s: %m", __func__);
    662 		return;
    663 	}
    664 	TAILQ_INIT(nrs);
    665 
    666 	TAILQ_FOREACH(ifp, ctx->ifaces, next) {
    667 		state = D_CSTATE(ifp);
    668 		if (state == NULL || state->new == NULL || !state->added)
    669 			continue;
    670 		dnr = get_routes(ifp);
    671 		dnr = massage_host_routes(dnr, ifp);
    672 		dnr = add_subnet_route(dnr, ifp);
    673 #ifdef IPV4_LOOPBACK_ROUTE
    674 		dnr = add_loopback_route(dnr, ifp);
    675 #endif
    676 		if (ifp->options->options & DHCPCD_GATEWAY) {
    677 			dnr = add_router_host_route(dnr, ifp);
    678 			dnr = add_destination_route(dnr, ifp);
    679 		}
    680 		if (dnr == NULL) /* failed to malloc all new routes */
    681 			continue;
    682 		TAILQ_FOREACH_SAFE(rt, dnr, next, rtn) {
    683 			rt->iface = ifp;
    684 #ifdef HAVE_ROUTE_METRIC
    685 			rt->metric = ifp->metric;
    686 #endif
    687 			rt->flags = state->added & STATE_FAKE;
    688 			/* Is this route already in our table? */
    689 			if ((find_route(nrs, rt, NULL)) != NULL)
    690 				continue;
    691 			rt->src.s_addr = state->addr.s_addr;
    692 			/* Do we already manage it? */
    693 			if ((or = find_route(ctx->ipv4_routes, rt, NULL))) {
    694 				if (state->added & STATE_FAKE)
    695 					continue;
    696 				if (or->flags & STATE_FAKE ||
    697 				    or->iface != ifp ||
    698 #ifdef HAVE_ROUTE_METRIC
    699 				    rt->metric != or->metric ||
    700 #endif
    701 				    or->src.s_addr != state->addr.s_addr ||
    702 				    rt->gate.s_addr != or->gate.s_addr)
    703 				{
    704 					if (c_route(or, rt) != 0)
    705 						continue;
    706 				}
    707 				TAILQ_REMOVE(ctx->ipv4_routes, or, next);
    708 				free(or);
    709 			} else {
    710 				if (state->added & STATE_FAKE) {
    711 					or = ipv4_findrt(ctx, rt, 1);
    712 					if (or == NULL ||
    713 					    or->gate.s_addr != rt->gate.s_addr)
    714  						continue;
    715 				} else {
    716 					if (n_route(rt) != 0)
    717 						continue;
    718 				}
    719 			}
    720 			rt->flags |= STATE_ADDED;
    721 			TAILQ_REMOVE(dnr, rt, next);
    722 			TAILQ_INSERT_TAIL(nrs, rt, next);
    723 		}
    724 		ipv4_freeroutes(dnr);
    725 	}
    726 
    727 	/* Remove old routes we used to manage */
    728 	if (ctx->ipv4_routes) {
    729 		TAILQ_FOREACH(rt, ctx->ipv4_routes, next) {
    730 			if (find_route(nrs, rt, NULL) == NULL &&
    731 			    (rt->iface->options->options &
    732 			    (DHCPCD_EXITING | DHCPCD_PERSISTENT)) !=
    733 			    (DHCPCD_EXITING | DHCPCD_PERSISTENT))
    734 				d_route(rt);
    735 		}
    736 	}
    737 	ipv4_freeroutes(ctx->ipv4_routes);
    738 	ctx->ipv4_routes = nrs;
    739 #endif
    740 }
    741 
    742 int
    743 ipv4_deladdr(struct interface *ifp,
    744     const struct in_addr *addr, const struct in_addr *net)
    745 {
    746 	int r = 0;
    747 #ifndef PASSIVE_MODE
    748 	struct dhcp_state *dstate;
    749 	struct ipv4_state *state;
    750 	struct ipv4_addr *ap;
    751 
    752 	logger(ifp->ctx, LOG_DEBUG, "%s: deleting IP address %s/%d",
    753 	    ifp->name, inet_ntoa(*addr), inet_ntocidr(*net));
    754 
    755 	r = if_deladdress(ifp, addr, net);
    756 	if (r == -1 && errno != EADDRNOTAVAIL && errno != ENXIO &&
    757 	    errno != ENODEV)
    758 		logger(ifp->ctx, LOG_ERR, "%s: %s: %m", ifp->name, __func__);
    759 
    760 	dstate = D_STATE(ifp);
    761 	if (dstate->addr.s_addr == addr->s_addr &&
    762 	    dstate->net.s_addr == net->s_addr)
    763 	{
    764 		dstate->added = 0;
    765 		dstate->addr.s_addr = 0;
    766 		dstate->net.s_addr = 0;
    767 	}
    768 
    769 	state = IPV4_STATE(ifp);
    770 	TAILQ_FOREACH(ap, &state->addrs, next) {
    771 		if (ap->addr.s_addr == addr->s_addr &&
    772 		    ap->net.s_addr == net->s_addr)
    773 		{
    774 			TAILQ_REMOVE(&state->addrs, ap, next);
    775 			free(ap);
    776 			break;
    777 		}
    778 	}
    779 #endif
    780 	return r;
    781 }
    782 
    783 static int
    784 delete_address(struct interface *ifp)
    785 {
    786 	int r;
    787 	struct if_options *ifo;
    788 	struct dhcp_state *state;
    789 
    790 	state = D_STATE(ifp);
    791 	ifo = ifp->options;
    792 	if (ifo->options & DHCPCD_INFORM ||
    793 	    (ifo->options & DHCPCD_STATIC && ifo->req_addr.s_addr == 0))
    794 		return 0;
    795 	r = ipv4_deladdr(ifp, &state->addr, &state->net);
    796 	return r;
    797 }
    798 
    799 static struct ipv4_state *
    800 ipv4_getstate(struct interface *ifp)
    801 {
    802 	struct ipv4_state *state;
    803 
    804 	state = IPV4_STATE(ifp);
    805 	if (state == NULL) {
    806 	        ifp->if_data[IF_DATA_IPV4] = malloc(sizeof(*state));
    807 		state = IPV4_STATE(ifp);
    808 		if (state == NULL) {
    809 			logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
    810 			return NULL;
    811 		}
    812 		TAILQ_INIT(&state->addrs);
    813 		TAILQ_INIT(&state->routes);
    814 	}
    815 	return state;
    816 }
    817 
    818 static int
    819 ipv4_addaddr(struct interface *ifp, const struct dhcp_lease *lease)
    820 {
    821 	struct ipv4_state *state;
    822 	struct ipv4_addr *ia;
    823 
    824 	if ((state = ipv4_getstate(ifp)) == NULL) {
    825 		logger(ifp->ctx, LOG_ERR, "%s: ipv4_getstate: %m", __func__);
    826 		return -1;
    827 	}
    828 	if (ifp->options->options & DHCPCD_NOALIAS) {
    829 		struct ipv4_addr *ian;
    830 
    831 		TAILQ_FOREACH_SAFE(ia, &state->addrs, next, ian) {
    832 			if (ia->addr.s_addr != lease->addr.s_addr)
    833 				ipv4_deladdr(ifp, &ia->addr, &ia->net);
    834 		}
    835 	}
    836 
    837 	if ((ia = malloc(sizeof(*ia))) == NULL) {
    838 		logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
    839 		return -1;
    840 	}
    841 
    842 	logger(ifp->ctx, LOG_DEBUG, "%s: adding IP address %s/%d",
    843 	    ifp->name, inet_ntoa(lease->addr),
    844 	    inet_ntocidr(lease->net));
    845 	if (if_addaddress(ifp, &lease->addr, &lease->net, &lease->brd) == -1) {
    846 		if (errno != EEXIST)
    847 			logger(ifp->ctx, LOG_ERR, "%s: if_addaddress: %m",
    848 			    __func__);
    849 		free(ia);
    850 		return -1;
    851 	}
    852 
    853 	ia->iface = ifp;
    854 	ia->addr = lease->addr;
    855 	ia->net = lease->net;
    856 #ifdef IN_IFF_TENTATIVE
    857 	ia->addr_flags = IN_IFF_TENTATIVE;
    858 #endif
    859 	TAILQ_INSERT_TAIL(&state->addrs, ia, next);
    860 	return 0;
    861 }
    862 
    863 static void
    864 ipv4_finalisert(struct interface *ifp)
    865 {
    866 	const struct dhcp_state *state = D_CSTATE(ifp);
    867 
    868 	/* Find any freshly added routes, such as the subnet route.
    869 	 * We do this because we cannot rely on recieving the kernel
    870 	 * notification right now via our link socket. */
    871 	if_initrt(ifp);
    872 	ipv4_buildroutes(ifp->ctx);
    873 	script_runreason(ifp, state->reason);
    874 
    875 	dhcpcd_daemonise(ifp->ctx);
    876 }
    877 
    878 void
    879 ipv4_finaliseaddr(struct interface *ifp)
    880 {
    881 #ifndef PASSIVE_MODE
    882 	struct dhcp_state *state = D_STATE(ifp);
    883 	struct dhcp_lease *lease;
    884 
    885 	lease = &state->lease;
    886 
    887 	/* Delete the old address if different */
    888 	if (state->addr.s_addr != lease->addr.s_addr &&
    889 	    state->addr.s_addr != 0 &&
    890 	    ipv4_iffindaddr(ifp, &lease->addr, NULL))
    891 		delete_address(ifp);
    892 
    893 	state->added = STATE_ADDED;
    894 	state->defend = 0;
    895 	state->addr.s_addr = lease->addr.s_addr;
    896 	state->net.s_addr = lease->net.s_addr;
    897 	ipv4_finalisert(ifp);
    898 #endif
    899 }
    900 
    901 void
    902 ipv4_applyaddr(void *arg)
    903 {
    904 #ifdef PASSIVE_MODE
    905 	rpc_update_ipv4(arg);
    906 #else
    907 	struct interface *ifp = arg, *ifn;
    908 	struct dhcp_state *state = D_STATE(ifp), *nstate;
    909 	struct dhcp_message *dhcp;
    910 	struct dhcp_lease *lease;
    911 	struct if_options *ifo = ifp->options;
    912 	struct ipv4_addr *ap;
    913 	int r;
    914 
    915 	if (state == NULL)
    916 		return;
    917 	dhcp = state->new;
    918 	lease = &state->lease;
    919 
    920 	if (dhcp == NULL) {
    921 		if ((ifo->options & (DHCPCD_EXITING | DHCPCD_PERSISTENT)) !=
    922 		    (DHCPCD_EXITING | DHCPCD_PERSISTENT))
    923 		{
    924 			if (state->added) {
    925 				struct in_addr addr;
    926 
    927 				addr = state->addr;
    928 				delete_address(ifp);
    929 				TAILQ_FOREACH(ifn, ifp->ctx->ifaces, next) {
    930 					if (ifn == ifp ||
    931 					    strcmp(ifn->name, ifp->name) == 0)
    932 						continue;
    933 					nstate = D_STATE(ifn);
    934 					if (nstate && !nstate->added &&
    935 					    nstate->addr.s_addr == addr.s_addr)
    936 					{
    937 						if (ifn->options->options &
    938 						    DHCPCD_ARP)
    939 						{
    940 							dhcp_bind(ifn, NULL);
    941 						} else {
    942 							ipv4_addaddr(ifn,
    943 							    &nstate->lease);
    944 							nstate->added =
    945 							    STATE_ADDED;
    946 						}
    947 						break;
    948 					}
    949 				}
    950 			}
    951 			ipv4_buildroutes(ifp->ctx);
    952 			script_runreason(ifp, state->reason);
    953 		} else
    954 			ipv4_buildroutes(ifp->ctx);
    955 		return;
    956 	}
    957 
    958 	/* Ensure only one interface has the address */
    959 	TAILQ_FOREACH(ifn, ifp->ctx->ifaces, next) {
    960 		if (ifn == ifp || strcmp(ifn->name, ifp->name) == 0)
    961 			continue;
    962 		nstate = D_STATE(ifn);
    963 		if (nstate && nstate->added &&
    964 		    nstate->addr.s_addr == lease->addr.s_addr)
    965 		{
    966 			if (ifn->metric <= ifp->metric) {
    967 				logger(ifp->ctx, LOG_INFO,
    968 				    "%s: preferring %s on %s",
    969 				    ifp->name,
    970 				    inet_ntoa(lease->addr),
    971 				    ifn->name);
    972 				state->addr.s_addr = lease->addr.s_addr;
    973 				state->net.s_addr = lease->net.s_addr;
    974 				ipv4_finalisert(ifp);
    975 			}
    976 			logger(ifp->ctx, LOG_INFO, "%s: preferring %s on %s",
    977 			    ifn->name,
    978 			    inet_ntoa(lease->addr),
    979 			    ifp->name);
    980 			ipv4_deladdr(ifn, &nstate->addr, &nstate->net);
    981 			nstate->added = 0;
    982 			break;
    983 		}
    984 	}
    985 
    986 	/* Does another interface already have the address from a prior boot? */
    987 	if (ifn == NULL) {
    988 		TAILQ_FOREACH(ifn, ifp->ctx->ifaces, next) {
    989 			if (ifn == ifp || strcmp(ifn->name, ifp->name) == 0)
    990 				continue;
    991 			ap = ipv4_iffindaddr(ifn, &lease->addr, NULL);
    992 			if (ap)
    993 				ipv4_deladdr(ifn, &ap->addr, &ap->net);
    994 		}
    995 	}
    996 
    997 	/* If the netmask is different, delete the addresss */
    998 	ap = ipv4_iffindaddr(ifp, &lease->addr, NULL);
    999 	if (ap && ap->net.s_addr != lease->net.s_addr)
   1000 		ipv4_deladdr(ifp, &ap->addr, &ap->net);
   1001 
   1002 	if (ipv4_iffindaddr(ifp, &lease->addr, &lease->net))
   1003 		logger(ifp->ctx, LOG_DEBUG,
   1004 		    "%s: IP address %s/%d already exists",
   1005 		    ifp->name, inet_ntoa(lease->addr),
   1006 		    inet_ntocidr(lease->net));
   1007 	else {
   1008 		r = ipv4_addaddr(ifp, lease);
   1009 		if (r == -1 && errno != EEXIST)
   1010 			return;
   1011 	}
   1012 
   1013 #ifdef IN_IFF_NOTUSEABLE
   1014 	ap = ipv4_iffindaddr(ifp, &lease->addr, NULL);
   1015 	if (ap == NULL) {
   1016 		logger(ifp->ctx, LOG_ERR, "%s: added address vanished",
   1017 		    ifp->name);
   1018 		return;
   1019 	} else if (ap->addr_flags & IN_IFF_NOTUSEABLE)
   1020 		return;
   1021 #endif
   1022 
   1023 	ipv4_finaliseaddr(ifp);
   1024 
   1025 #endif  /* PASSIVE_MODE */
   1026 }
   1027 
   1028 void
   1029 ipv4_handleifa(struct dhcpcd_ctx *ctx,
   1030     int cmd, struct if_head *ifs, const char *ifname,
   1031     const struct in_addr *addr, const struct in_addr *net,
   1032     const struct in_addr *dst, int flags)
   1033 {
   1034 	struct interface *ifp;
   1035 	struct ipv4_state *state;
   1036 	struct ipv4_addr *ap;
   1037 
   1038 	if (ifs == NULL)
   1039 		ifs = ctx->ifaces;
   1040 	if (ifs == NULL) {
   1041 		errno = ESRCH;
   1042 		return;
   1043 	}
   1044 	if (addr->s_addr == INADDR_ANY) {
   1045 		errno = EINVAL;
   1046 		return;
   1047 	}
   1048 	if ((ifp = if_find(ifs, ifname)) == NULL)
   1049 		return;
   1050 	if ((state = ipv4_getstate(ifp)) == NULL) {
   1051 		errno = ENOENT;
   1052 		return;
   1053 	}
   1054 
   1055 	ap = ipv4_iffindaddr(ifp, addr, net);
   1056 	if (cmd == RTM_NEWADDR) {
   1057 		if (ap == NULL) {
   1058 			if ((ap = malloc(sizeof(*ap))) == NULL) {
   1059 				logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
   1060 				return;
   1061 			}
   1062 			ap->iface = ifp;
   1063 			ap->addr = *addr;
   1064 			ap->net = *net;
   1065 			if (dst)
   1066 				ap->dst.s_addr = dst->s_addr;
   1067 			else
   1068 				ap->dst.s_addr = INADDR_ANY;
   1069 			TAILQ_INSERT_TAIL(&state->addrs, ap, next);
   1070 		}
   1071 		ap->addr_flags = flags;
   1072 	} else if (cmd == RTM_DELADDR) {
   1073 		if (ap) {
   1074 			TAILQ_REMOVE(&state->addrs, ap, next);
   1075 			free(ap);
   1076 		}
   1077 	}
   1078 
   1079 	dhcp_handleifa(cmd, ifp, addr, net, dst, flags);
   1080 	arp_handleifa(cmd, ifp, addr, flags);
   1081 }
   1082 
   1083 void
   1084 ipv4_free(struct interface *ifp)
   1085 {
   1086 	struct ipv4_state *state;
   1087 	struct ipv4_addr *addr;
   1088 
   1089 	if (ifp) {
   1090 		state = IPV4_STATE(ifp);
   1091 		if (state) {
   1092 		        while ((addr = TAILQ_FIRST(&state->addrs))) {
   1093 				TAILQ_REMOVE(&state->addrs, addr, next);
   1094 				free(addr);
   1095 			}
   1096 			ipv4_freerts(&state->routes);
   1097 			free(state);
   1098 		}
   1099 	}
   1100 }
   1101 
   1102 void
   1103 ipv4_ctxfree(struct dhcpcd_ctx *ctx)
   1104 {
   1105 
   1106 	ipv4_freeroutes(ctx->ipv4_routes);
   1107 	ipv4_freeroutes(ctx->ipv4_kroutes);
   1108 }
   1109