/* SPDX-License-Identifier: BSD-2-Clause */
/*
 * dhcpcd - DHCP client daemon
 * Copyright (c) 2006-2019 Roy Marples <roy@marples.name>
 * All rights reserved

 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

const char dhcpcd_copyright[] = "Copyright (c) 2006-2019 Roy Marples";

#include <sys/file.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/uio.h>

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <limits.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <syslog.h>

#include "config.h"
#include "arp.h"
#include "common.h"
#include "control.h"
#include "dev.h"
#include "dhcp-common.h"
#include "dhcpcd.h"
#include "dhcp.h"
#include "dhcp6.h"
#include "duid.h"
#include "eloop.h"
#include "if.h"
#include "if-options.h"
#include "ipv4.h"
#include "ipv4ll.h"
#include "ipv6.h"
#include "ipv6nd.h"
#include "logerr.h"
#include "script.h"

#ifdef HAVE_UTIL_H
#include <util.h>
#endif

#ifdef USE_SIGNALS
const int dhcpcd_signals[] = {
	SIGTERM,
	SIGINT,
	SIGALRM,
	SIGHUP,
	SIGUSR1,
	SIGUSR2,
	SIGPIPE
};
const size_t dhcpcd_signals_len = __arraycount(dhcpcd_signals);
#endif

#define IF_UPANDRUNNING(a) \
	(((a)->flags & (IFF_UP | IFF_RUNNING)) == (IFF_UP | IFF_RUNNING))

static void
usage(void)
{

printf("usage: "PACKAGE"\t[-146ABbDdEGgHJKLMNPpqTV]\n"
	"\t\t[-C, --nohook hook] [-c, --script script]\n"
	"\t\t[-e, --env value] [-F, --fqdn FQDN] [-f, --config file]\n"
	"\t\t[-h, --hostname hostname] [-I, --clientid clientid]\n"
	"\t\t[-i, --vendorclassid vendorclassid] [-j, --logfile logfile]\n" 
	"\t\t[-l, --leasetime seconds] [-m, --metric metric]\n"
	"\t\t[-O, --nooption option] [-o, --option option]\n"
	"\t\t[-Q, --require option] [-r, --request address]\n"
	"\t\t[-S, --static value]\n"
	"\t\t[-s, --inform address[/cidr[/broadcast_address]]]\n [--inform6]"
	"\t\t[-t, --timeout seconds] [-u, --userclass class]\n"
	"\t\t[-v, --vendor code, value] [-W, --whitelist address[/cidr]] [-w]\n"
	"\t\t[--waitip [4 | 6]] [-y, --reboot seconds]\n"
	"\t\t[-X, --blacklist address[/cidr]] [-Z, --denyinterfaces pattern]\n"
	"\t\t[-z, --allowinterfaces pattern] [--inactive] [interface] [...]\n"
	"       "PACKAGE"\t-n, --rebind [interface]\n"
	"       "PACKAGE"\t-k, --release [interface]\n"
	"       "PACKAGE"\t-U, --dumplease interface\n"
	"       "PACKAGE"\t--version\n"
	"       "PACKAGE"\t-x, --exit [interface]\n");
}

static void
free_globals(struct dhcpcd_ctx *ctx)
{
	struct dhcp_opt *opt;

	if (ctx->ifac) {
		for (; ctx->ifac > 0; ctx->ifac--)
			free(ctx->ifav[ctx->ifac - 1]);
		free(ctx->ifav);
		ctx->ifav = NULL;
	}
	if (ctx->ifdc) {
		for (; ctx->ifdc > 0; ctx->ifdc--)
			free(ctx->ifdv[ctx->ifdc - 1]);
		free(ctx->ifdv);
		ctx->ifdv = NULL;
	}
	if (ctx->ifcc) {
		for (; ctx->ifcc > 0; ctx->ifcc--)
			free(ctx->ifcv[ctx->ifcc - 1]);
		free(ctx->ifcv);
		ctx->ifcv = NULL;
	}

#ifdef INET
	if (ctx->dhcp_opts) {
		for (opt = ctx->dhcp_opts;
		    ctx->dhcp_opts_len > 0;
		    opt++, ctx->dhcp_opts_len--)
			free_dhcp_opt_embenc(opt);
		free(ctx->dhcp_opts);
		ctx->dhcp_opts = NULL;
	}
#endif
#ifdef INET6
	if (ctx->nd_opts) {
		for (opt = ctx->nd_opts;
		    ctx->nd_opts_len > 0;
		    opt++, ctx->nd_opts_len--)
			free_dhcp_opt_embenc(opt);
		free(ctx->nd_opts);
		ctx->nd_opts = NULL;
	}
#ifdef DHCP6
	if (ctx->dhcp6_opts) {
		for (opt = ctx->dhcp6_opts;
		    ctx->dhcp6_opts_len > 0;
		    opt++, ctx->dhcp6_opts_len--)
			free_dhcp_opt_embenc(opt);
		free(ctx->dhcp6_opts);
		ctx->dhcp6_opts = NULL;
	}
#endif
#endif
	if (ctx->vivso) {
		for (opt = ctx->vivso;
		    ctx->vivso_len > 0;
		    opt++, ctx->vivso_len--)
			free_dhcp_opt_embenc(opt);
		free(ctx->vivso);
		ctx->vivso = NULL;
	}
}

static void
handle_exit_timeout(void *arg)
{
	struct dhcpcd_ctx *ctx;

	ctx = arg;
	logerrx("timed out");
	if (!(ctx->options & DHCPCD_MASTER)) {
		struct interface *ifp;

		TAILQ_FOREACH(ifp, ctx->ifaces, next) {
			if (ifp->active == IF_ACTIVE_USER)
				script_runreason(ifp, "STOPPED");
		}
		eloop_exit(ctx->eloop, EXIT_FAILURE);
		return;
	}
	ctx->options |= DHCPCD_NOWAITIP;
	dhcpcd_daemonise(ctx);
}

static const char *
dhcpcd_af(int af)
{

	switch (af) {
	case AF_UNSPEC:
		return "IP";
	case AF_INET:
		return "IPv4";
	case AF_INET6:
		return "IPv6";
	default:
		return NULL;
	}
}

int
dhcpcd_ifafwaiting(const struct interface *ifp)
{
	unsigned long long opts;
	bool foundany = false;

	if (ifp->active != IF_ACTIVE_USER)
		return AF_MAX;

#define DHCPCD_WAITALL	(DHCPCD_WAITIP4 | DHCPCD_WAITIP6)
	opts = ifp->options->options;
#ifdef INET
	if (opts & DHCPCD_WAITIP4 ||
	    (opts & DHCPCD_WAITIP && !(opts & DHCPCD_WAITALL)))
	{
		bool foundaddr = ipv4_hasaddr(ifp);

		if (opts & DHCPCD_WAITIP4 && !foundaddr)
			return AF_INET;
		if (foundaddr)
			foundany = true;
	}
#endif
#ifdef INET6
	if (opts & DHCPCD_WAITIP6 ||
	    (opts & DHCPCD_WAITIP && !(opts & DHCPCD_WAITALL)))
	{
		bool foundaddr = ipv6_hasaddr(ifp);

		if (opts & DHCPCD_WAITIP6 && !foundaddr)
			return AF_INET;
		if (foundaddr)
			foundany = true;
	}
#endif

	if (opts & DHCPCD_WAITIP && !(opts & DHCPCD_WAITALL) && !foundany)
		return AF_UNSPEC;
	return AF_MAX;
}

int
dhcpcd_afwaiting(const struct dhcpcd_ctx *ctx)
{
	unsigned long long opts;
	const struct interface *ifp;
	int af;

	if (!(ctx->options & DHCPCD_WAITOPTS))
		return AF_MAX;

	opts = ctx->options;
	TAILQ_FOREACH(ifp, ctx->ifaces, next) {
#ifdef INET
		if (opts & (DHCPCD_WAITIP | DHCPCD_WAITIP4) &&
		    ipv4_hasaddr(ifp))
			opts &= ~(DHCPCD_WAITIP | DHCPCD_WAITIP4);
#endif
#ifdef INET6
		if (opts & (DHCPCD_WAITIP | DHCPCD_WAITIP6) &&
		    ipv6_hasaddr(ifp))
			opts &= ~(DHCPCD_WAITIP | DHCPCD_WAITIP6);
#endif
		if (!(opts & DHCPCD_WAITOPTS))
			break;
	}
	if (opts & DHCPCD_WAITIP)
		af = AF_UNSPEC;
	else if (opts & DHCPCD_WAITIP4)
		af = AF_INET;
	else if (opts & DHCPCD_WAITIP6)
		af = AF_INET6;
	else
		return AF_MAX;
	return af;
}

static int
dhcpcd_ipwaited(struct dhcpcd_ctx *ctx)
{
	struct interface *ifp;
	int af;

	TAILQ_FOREACH(ifp, ctx->ifaces, next) {
		if ((af = dhcpcd_ifafwaiting(ifp)) != AF_MAX) {
			logdebugx("%s: waiting for an %s address",
			    ifp->name, dhcpcd_af(af));
			return 0;
		}
	}

	if ((af = dhcpcd_afwaiting(ctx)) != AF_MAX) {
		logdebugx("waiting for an %s address",
		    dhcpcd_af(af));
		return 0;
	}

	return 1;
}

/* Returns the pid of the child, otherwise 0. */
pid_t
dhcpcd_daemonise(struct dhcpcd_ctx *ctx)
{
#ifdef THERE_IS_NO_FORK
	eloop_timeout_delete(ctx->eloop, handle_exit_timeout, ctx);
	errno = ENOSYS;
	return 0;
#else
	pid_t pid, lpid;
	char buf = '\0';
	int sidpipe[2], fd;

	if (ctx->options & DHCPCD_DAEMONISE &&
	    !(ctx->options & (DHCPCD_DAEMONISED | DHCPCD_NOWAITIP)))
	{
		if (!dhcpcd_ipwaited(ctx))
			return 0;
	}

	if (ctx->options & DHCPCD_ONESHOT) {
		loginfox("exiting due to oneshot");
		eloop_exit(ctx->eloop, EXIT_SUCCESS);
		return 0;
	}

	eloop_timeout_delete(ctx->eloop, handle_exit_timeout, ctx);
	if (ctx->options & DHCPCD_DAEMONISED ||
	    !(ctx->options & DHCPCD_DAEMONISE))
		return 0;
	logdebugx("forking to background");

	/* Setup a signal pipe so parent knows when to exit. */
	if (pipe(sidpipe) == -1) {
		logerr("%s: pipe", __func__);
		return 0;
	}

	switch (pid = fork()) {
	case -1:
		logerr("%s: fork", __func__);
		return 0;
	case 0:
		if ((lpid = pidfile_lock(ctx->pidfile)) != 0)
			logerr("%s: pidfile_lock %d", __func__, lpid);
		setsid();
		/* Notify parent it's safe to exit as we've detached. */
		close(sidpipe[0]);
		if (write(sidpipe[1], &buf, 1) == -1)
			logerr("%s: write", __func__);
		close(sidpipe[1]);
		/* Some polling methods don't survive after forking,
		 * so ensure we can requeue all our events. */
		if (eloop_requeue(ctx->eloop) == -1) {
			logerr("%s: eloop_requeue", __func__);
			eloop_exit(ctx->eloop, EXIT_FAILURE);
		}
		if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
			dup2(fd, STDIN_FILENO);
			dup2(fd, STDOUT_FILENO);
			dup2(fd, STDERR_FILENO);
			close(fd);
		}
		ctx->options |= DHCPCD_DAEMONISED;
		return 0;
	default:
		/* Wait for child to detach */
		close(sidpipe[1]);
		if (read(sidpipe[0], &buf, 1) == -1)
			logerr("%s: read", __func__);
		close(sidpipe[0]);
		loginfox("forked to background, child pid %d", pid);
		ctx->options |= DHCPCD_FORKED;
		eloop_exit(ctx->eloop, EXIT_SUCCESS);
		return pid;
	}
#endif
}

static void
dhcpcd_drop(struct interface *ifp, int stop)
{

#ifdef DHCP6
	dhcp6_drop(ifp, stop ? NULL : "EXPIRE6");
#endif
#ifdef INET6
	ipv6nd_drop(ifp);
	ipv6_drop(ifp);
#endif
#ifdef IPV4LL
	ipv4ll_drop(ifp);
#endif
#ifdef INET
	dhcp_drop(ifp, stop ? "STOP" : "EXPIRE");
#endif
#ifdef ARP
	arp_drop(ifp);
#endif
#if !defined(DHCP6) && !defined(DHCP)
	UNUSED(stop);
#endif
}

static void
stop_interface(struct interface *ifp)
{
	struct dhcpcd_ctx *ctx;

	ctx = ifp->ctx;
	loginfox("%s: removing interface", ifp->name);
	ifp->options->options |= DHCPCD_STOPPING;

	dhcpcd_drop(ifp, 1);
	if (ifp->options->options & DHCPCD_DEPARTED)
		script_runreason(ifp, "DEPARTED");
	else
		script_runreason(ifp, "STOPPED");

	/* Delete all timeouts for the interfaces */
	eloop_q_timeout_delete(ctx->eloop, ELOOP_QUEUE_ALL, NULL, ifp);

	/* De-activate the interface */
	ifp->active = IF_INACTIVE;
	ifp->options->options &= ~DHCPCD_STOPPING;
	/* Set the link state to unknown as we're no longer tracking it. */
	ifp->carrier = LINK_UNKNOWN;

	if (!(ctx->options & (DHCPCD_MASTER | DHCPCD_TEST)))
		eloop_exit(ctx->eloop, EXIT_FAILURE);
}

static void
configure_interface1(struct interface *ifp)
{
	struct if_options *ifo = ifp->options;

	/* Do any platform specific configuration */
	if_conf(ifp);

	/* If we want to release a lease, we can't really persist the
	 * address either. */
	if (ifo->options & DHCPCD_RELEASE)
		ifo->options &= ~DHCPCD_PERSISTENT;

	if (ifp->flags & (IFF_POINTOPOINT | IFF_LOOPBACK)) {
		ifo->options &= ~DHCPCD_ARP;
		if (!(ifp->flags & IFF_MULTICAST))
			ifo->options &= ~DHCPCD_IPV6RS;
		if (!(ifo->options & (DHCPCD_INFORM | DHCPCD_WANTDHCP)))
			ifo->options |= DHCPCD_STATIC;
	}

	if (ifo->metric != -1)
		ifp->metric = (unsigned int)ifo->metric;

#ifdef INET6
	/* We want to setup INET6 on the interface as soon as possible. */
	if (ifp->active == IF_ACTIVE_USER &&
	    ifo->options & DHCPCD_IPV6 &&
	    !(ifp->ctx->options & (DHCPCD_DUMPLEASE | DHCPCD_TEST)))
	{
		/* If not doing any DHCP, disable the RDNSS requirement. */
		if (!(ifo->options & (DHCPCD_DHCP | DHCPCD_DHCP6)))
			ifo->options &= ~DHCPCD_IPV6RA_REQRDNSS;
		if_setup_inet6(ifp);
	}
#endif

	if (!(ifo->options & DHCPCD_IAID)) {
		/*
		 * An IAID is for identifying a unqiue interface within
		 * the client. It is 4 bytes long. Working out a default
		 * value is problematic.
		 *
		 * Interface name and number are not stable
		 * between different OS's. Some OS's also cannot make
		 * up their mind what the interface should be called
		 * (yes, udev, I'm looking at you).
		 * Also, the name could be longer than 4 bytes.
		 * Also, with pluggable interfaces the name and index
		 * could easily get swapped per actual interface.
		 *
		 * The MAC address is 6 bytes long, the final 3
		 * being unique to the manufacturer and the initial 3
		 * being unique to the organisation which makes it.
		 * We could use the last 4 bytes of the MAC address
		 * as the IAID as it's the most stable part given the
		 * above, but equally it's not guaranteed to be
		 * unique.
		 *
		 * Given the above, and our need to reliably work
		 * between reboots without persitent storage,
		 * generating the IAID from the MAC address is the only
		 * logical default.
		 * Saying that, if a VLANID has been specified then we
		 * can use that. It's possible that different interfaces
		 * can have the same VLANID, but this is no worse than
		 * generating the IAID from the duplicate MAC address.
		 *
		 * dhclient uses the last 4 bytes of the MAC address.
		 * dibbler uses an increamenting counter.
		 * wide-dhcpv6 uses 0 or a configured value.
		 * odhcp6c uses 1.
		 * Windows 7 uses the first 3 bytes of the MAC address
		 * and an unknown byte.
		 * dhcpcd-6.1.0 and earlier used the interface name,
		 * falling back to interface index if name > 4.
		 */
		if (ifp->vlanid != 0) {
			uint32_t vlanid;

			/* Maximal VLANID is 4095, so prefix with 0xff
			 * so we don't conflict with an interface index. */
			vlanid = htonl(ifp->vlanid | 0xff000000);
			memcpy(ifo->iaid, &vlanid, sizeof(vlanid));
		} else if (ifp->hwlen >= sizeof(ifo->iaid)) {
			memcpy(ifo->iaid,
			    ifp->hwaddr + ifp->hwlen - sizeof(ifo->iaid),
			    sizeof(ifo->iaid));
		} else {
			uint32_t len;

			len = (uint32_t)strlen(ifp->name);
			if (len <= sizeof(ifo->iaid)) {
				memcpy(ifo->iaid, ifp->name, len);
				if (len < sizeof(ifo->iaid))
					memset(ifo->iaid + len, 0,
					    sizeof(ifo->iaid) - len);
			} else {
				/* IAID is the same size as a uint32_t */
				len = htonl(ifp->index);
				memcpy(ifo->iaid, &len, sizeof(ifo->iaid));
			}
		}
		ifo->options |= DHCPCD_IAID;
	}

#ifdef DHCP6
	if (ifo->ia_len == 0 && ifo->options & DHCPCD_IPV6 &&
	    ifp->name[0] != '\0')
	{
		ifo->ia = malloc(sizeof(*ifo->ia));
		if (ifo->ia == NULL)
			logerr(__func__);
		else {
			ifo->ia_len = 1;
			ifo->ia->ia_type = D6_OPTION_IA_NA;
			memcpy(ifo->ia->iaid, ifo->iaid, sizeof(ifo->iaid));
			memset(&ifo->ia->addr, 0, sizeof(ifo->ia->addr));
#ifndef SMALL
			ifo->ia->sla = NULL;
			ifo->ia->sla_len = 0;
#endif
		}
	} else {
		size_t i;

		for (i = 0; i < ifo->ia_len; i++) {
			if (!ifo->ia[i].iaid_set) {
				memcpy(&ifo->ia[i].iaid, ifo->iaid,
				    sizeof(ifo->ia[i].iaid));
				ifo->ia[i].iaid_set = 1;
			}
		}
	}
#endif

	/* If root is network mounted, we don't want to kill the connection
	 * if the DHCP server goes the way of the dodo OR dhcpcd is rebooting
	 * and the lease file has expired. */
	if (is_root_local() == 0)
		ifo->options |= DHCPCD_LASTLEASE_EXTEND;
}

int
dhcpcd_selectprofile(struct interface *ifp, const char *profile)
{
	struct if_options *ifo;
	char pssid[PROFILE_LEN];

	if (ifp->ssid_len) {
		ssize_t r;

		r = print_string(pssid, sizeof(pssid), OT_ESCSTRING,
		    ifp->ssid, ifp->ssid_len);
		if (r == -1) {
			logerr(__func__);
			pssid[0] = '\0';
		}
	} else
		pssid[0] = '\0';
	ifo = read_config(ifp->ctx, ifp->name, pssid, profile);
	if (ifo == NULL) {
		logdebugx("%s: no profile %s", ifp->name, profile);
		return -1;
	}
	if (profile != NULL) {
		strlcpy(ifp->profile, profile, sizeof(ifp->profile));
		loginfox("%s: selected profile %s", ifp->name, profile);
	} else
		*ifp->profile = '\0';

	free_options(ifp->ctx, ifp->options);
	ifp->options = ifo;
	if (profile) {
		add_options(ifp->ctx, ifp->name, ifp->options,
		    ifp->ctx->argc, ifp->ctx->argv);
		configure_interface1(ifp);
	}
	return 1;
}

static void
configure_interface(struct interface *ifp, int argc, char **argv,
    unsigned long long options)
{
	time_t old;

	old = ifp->options ? ifp->options->mtime : 0;
	dhcpcd_selectprofile(ifp, NULL);
	if (ifp->options == NULL) {
		/* dhcpcd cannot continue with this interface. */
		ifp->active = IF_INACTIVE;
		return;
	}
	add_options(ifp->ctx, ifp->name, ifp->options, argc, argv);
	ifp->options->options |= options;
	configure_interface1(ifp);

	/* If the mtime has changed drop any old lease */
	if (old != 0 && ifp->options->mtime != old) {
		logwarnx("%s: confile file changed, expiring leases",
		    ifp->name);
		dhcpcd_drop(ifp, 0);
	}
}

static void
dhcpcd_initstate2(struct interface *ifp, unsigned long long options)
{
	struct if_options *ifo;

	if (options) {
		if ((ifo = default_config(ifp->ctx)) == NULL) {
			logerr(__func__);
			return;
		}
		ifo->options |= options;
		free(ifp->options);
		ifp->options = ifo;
	} else
		ifo = ifp->options;

#ifdef INET6
	if (ifo->options & DHCPCD_IPV6 && ipv6_init(ifp->ctx) == -1) {
		logerr(__func__);
		ifo->options &= ~DHCPCD_IPV6;
	}
#endif
}

static void
dhcpcd_initstate1(struct interface *ifp, int argc, char **argv,
    unsigned long long options)
{

	configure_interface(ifp, argc, argv, options);
	if (ifp->active)
		dhcpcd_initstate2(ifp, 0);
}

static void
dhcpcd_initstate(struct interface *ifp, unsigned long long options)
{

	dhcpcd_initstate1(ifp, ifp->ctx->argc, ifp->ctx->argv, options);
}

static void
dhcpcd_reportssid(struct interface *ifp)
{
	char pssid[IF_SSIDLEN * 4];

	if (print_string(pssid, sizeof(pssid), OT_ESCSTRING,
	    ifp->ssid, ifp->ssid_len) == -1)
	{
		logerr(__func__);
		return;
	}

	loginfox("%s: connected to Access Point `%s'", ifp->name, pssid);
}

void
dhcpcd_handlecarrier(struct dhcpcd_ctx *ctx, int carrier, unsigned int flags,
    const char *ifname)
{
	struct interface *ifp;

	ifp = if_find(ctx->ifaces, ifname);
	if (ifp == NULL ||
	    ifp->options == NULL || !(ifp->options->options & DHCPCD_LINK) ||
	    !ifp->active)
		return;

	if (carrier == LINK_UNKNOWN) {
		if (ifp->wireless) {
			carrier = LINK_DOWN;
			ifp->flags = flags;
		} else
			carrier = if_carrier(ifp);
	} else
		ifp->flags = flags;
	if (carrier == LINK_UNKNOWN)
		carrier = IF_UPANDRUNNING(ifp) ? LINK_UP : LINK_DOWN;

	if (carrier == LINK_DOWN || (ifp->flags & IFF_UP) == 0) {
		if (ifp->carrier != LINK_DOWN) {
			if (ifp->carrier == LINK_UP)
				loginfox("%s: carrier lost", ifp->name);
#ifdef NOCARRIER_PRESERVE_IP
			if (ifp->flags & IFF_UP)
				ifp->carrier = LINK_DOWN_IFFUP;
			else
#endif
				ifp->carrier = LINK_DOWN;
			script_runreason(ifp, "NOCARRIER");
#ifdef NOCARRIER_PRESERVE_IP
			if (ifp->flags & IFF_UP) {
#ifdef ARP
				arp_drop(ifp);
#endif
#ifdef INET
				dhcp_abort(ifp);
#endif
#ifdef DHCP6
				dhcp6_abort(ifp);
#endif
			} else
#endif
				dhcpcd_drop(ifp, 0);
		}
	} else if (carrier == LINK_UP && ifp->flags & IFF_UP) {
		if (ifp->carrier != LINK_UP) {
			loginfox("%s: carrier acquired", ifp->name);
			ifp->carrier = LINK_UP;
#if !defined(__linux__) && !defined(__NetBSD__)
			/* BSD does not emit RTM_NEWADDR or RTM_CHGADDR when the
			 * hardware address changes so we have to go
			 * through the disovery process to work it out. */
			dhcpcd_handleinterface(ctx, 0, ifp->name);
#endif
			if (ifp->wireless) {
				uint8_t ossid[IF_SSIDLEN];
				size_t olen;

				olen = ifp->ssid_len;
				memcpy(ossid, ifp->ssid, ifp->ssid_len);
				if_getssid(ifp);

				/* If we changed SSID network, drop leases */
				if (ifp->ssid_len != olen ||
				    memcmp(ifp->ssid, ossid, ifp->ssid_len))
				{
					dhcpcd_reportssid(ifp);
#ifdef NOCARRIER_PRESERVE_IP
					dhcpcd_drop(ifp, 0);
#endif
#ifdef IPV4LL
					ipv4ll_reset(ifp);
#endif
				}
			}
			dhcpcd_initstate(ifp, 0);
			script_runreason(ifp, "CARRIER");
#ifdef INET6
#ifdef NOCARRIER_PRESERVE_IP
			/* Set any IPv6 Routers we remembered to expire
			 * faster than they would normally as we
			 * maybe on a new network. */
			ipv6nd_startexpire(ifp);
#endif
			/* RFC4941 Section 3.5 */
			ipv6_gentempifid(ifp);
#endif
			dhcpcd_startinterface(ifp);
		}
	}
}

static void
warn_iaid_conflict(struct interface *ifp, uint16_t ia_type, uint8_t *iaid)
{
	struct interface *ifn;
#ifdef INET6
	size_t i;
	struct if_ia *ia;
#endif

	TAILQ_FOREACH(ifn, ifp->ctx->ifaces, next) {
		if (ifn == ifp || !ifn->active)
			continue;
		if (ia_type == 0 &&
		    memcmp(ifn->options->iaid, iaid,
		    sizeof(ifn->options->iaid)) == 0)
			break;
#ifdef INET6
		for (i = 0; i < ifn->options->ia_len; i++) {
			ia = &ifn->options->ia[i];
			if (ia->ia_type == ia_type &&
			    memcmp(ia->iaid, iaid, sizeof(ia->iaid)) == 0)
				break;
		}
#endif
	}

	/* This is only a problem if the interfaces are on the same network. */
	if (ifn)
		logerrx("%s: IAID conflicts with one assigned to %s",
		    ifp->name, ifn->name);
}

void
dhcpcd_startinterface(void *arg)
{
	struct interface *ifp = arg;
	struct if_options *ifo = ifp->options;
	char buf[DUID_LEN * 3];
	int carrier;

	if (ifo->options & DHCPCD_LINK) {
		switch (ifp->carrier) {
		case LINK_UP:
			break;
		case LINK_DOWN:
			loginfox("%s: waiting for carrier", ifp->name);
			return;
		case LINK_UNKNOWN:
			/* No media state available.
			 * Loop until both IFF_UP and IFF_RUNNING are set */
			carrier = if_carrier(ifp);
			if (carrier == LINK_UNKNOWN) {
				if (IF_UPANDRUNNING(ifp))
					carrier = LINK_UP;
				else {
					struct timespec tv;

					tv.tv_sec = 0;
					tv.tv_nsec = IF_POLL_UP * NSEC_PER_MSEC;
					eloop_timeout_add_tv(ifp->ctx->eloop,
					    &tv, dhcpcd_startinterface, ifp);
					return;
				}
			}
			dhcpcd_handlecarrier(ifp->ctx, carrier,
			    ifp->flags, ifp->name);
			return;
		}
	}

	if (ifo->options & (DHCPCD_DUID | DHCPCD_IPV6)) {
		/* Report client DUID */
		if (ifp->ctx->duid == NULL) {
			if (duid_init(ifp) == 0)
				return;
			loginfox("DUID %s",
			    hwaddr_ntoa(ifp->ctx->duid,
			    ifp->ctx->duid_len,
			    buf, sizeof(buf)));
		}
	}

	if (ifo->options & (DHCPCD_DUID | DHCPCD_IPV6)) {
#ifdef INET6
		size_t i;
		struct if_ia *ia;
#endif

		/* Report IAIDs */
		loginfox("%s: IAID %s", ifp->name,
		    hwaddr_ntoa(ifo->iaid, sizeof(ifo->iaid),
		    buf, sizeof(buf)));
		warn_iaid_conflict(ifp, 0, ifo->iaid);
#ifdef INET6
		for (i = 0; i < ifo->ia_len; i++) {
			ia = &ifo->ia[i];
			if (memcmp(ifo->iaid, ia->iaid, sizeof(ifo->iaid))) {
				loginfox("%s: IA type %u IAID %s",
				    ifp->name, ia->ia_type,
				    hwaddr_ntoa(ia->iaid, sizeof(ia->iaid),
				    buf, sizeof(buf)));
				warn_iaid_conflict(ifp, ia->ia_type, ia->iaid);
			}
		}
#endif
	}

#ifdef INET6
	if (ifo->options & DHCPCD_IPV6 && ipv6_start(ifp) == -1) {
		logerr("%s: ipv6_start", ifp->name);
		ifo->options &= ~DHCPCD_IPV6;
	}

	if (ifo->options & DHCPCD_IPV6) {
		if (ifp->active == IF_ACTIVE_USER) {
			ipv6_startstatic(ifp);

			if (ifo->options & DHCPCD_IPV6RS)
				ipv6nd_startrs(ifp);
		}

#ifdef DHCP6
		/* DHCPv6 could be turned off, but the interface
		 * is still delegated to. */
		if (ifp->active)
			dhcp6_find_delegates(ifp);

		if (ifo->options & DHCPCD_DHCP6) {
			if (ifp->active == IF_ACTIVE_USER) {
				enum DH6S d6_state;

				if (ifo->options & DHCPCD_IA_FORCED)
					d6_state = DH6S_INIT;
				else if (ifo->options & DHCPCD_INFORM6)
					d6_state = DH6S_INFORM;
				else
					d6_state = DH6S_CONFIRM;
				if (dhcp6_start(ifp, d6_state) == -1)
					logerr("%s: dhcp6_start", ifp->name);
			}
		}
#endif
	}
#endif

#ifdef INET
	if (ifo->options & DHCPCD_IPV4 && ifp->active == IF_ACTIVE_USER) {
		/* Ensure we have an IPv4 state before starting DHCP */
		if (ipv4_getstate(ifp) != NULL)
			dhcp_start(ifp);
	}
#endif
}

static void
dhcpcd_prestartinterface(void *arg)
{
	struct interface *ifp = arg;

	if ((!(ifp->ctx->options & DHCPCD_MASTER) ||
	    ifp->options->options & DHCPCD_IF_UP) &&
	    if_up(ifp) == -1)
		logerr("%s: %s", __func__, ifp->name);

	dhcpcd_startinterface(ifp);
}

static void
run_preinit(struct interface *ifp)
{

	if (ifp->ctx->options & DHCPCD_TEST)
		return;

	script_runreason(ifp, "PREINIT");
	if (ifp->wireless && ifp->carrier == LINK_UP)
		dhcpcd_reportssid(ifp);
	if (ifp->options->options & DHCPCD_LINK && ifp->carrier != LINK_UNKNOWN)
		script_runreason(ifp,
		    ifp->carrier == LINK_UP ? "CARRIER" : "NOCARRIER");
}

void
dhcpcd_activateinterface(struct interface *ifp, unsigned long long options)
{

	if (!ifp->active) {
		ifp->active = IF_ACTIVE;
		dhcpcd_initstate2(ifp, options);
		/* It's possible we might not have been able to load
		 * a config. */
		if (ifp->active) {
			configure_interface1(ifp);
			run_preinit(ifp);
			dhcpcd_prestartinterface(ifp);
		}
	}
}

int
dhcpcd_handleinterface(void *arg, int action, const char *ifname)
{
	struct dhcpcd_ctx *ctx;
	struct ifaddrs *ifaddrs;
	struct if_head *ifs;
	struct interface *ifp, *iff;
	const char * const argv[] = { ifname };
	int e;

	ctx = arg;
	if (action == -1) {
		ifp = if_find(ctx->ifaces, ifname);
		if (ifp == NULL) {
			errno = ESRCH;
			return -1;
		}
		if (ifp->active) {
			logdebugx("%s: interface departed", ifp->name);
			ifp->options->options |= DHCPCD_DEPARTED;
			stop_interface(ifp);
		}
		TAILQ_REMOVE(ctx->ifaces, ifp, next);
		if_free(ifp);
		return 0;
	}

	ifs = if_discover(ctx, &ifaddrs, -1, UNCONST(argv));
	if (ifs == NULL) {
		logerr(__func__);
		return -1;
	}

	ifp = if_find(ifs, ifname);
	if (ifp == NULL) {
		/* This can happen if an interface is quickly added
		 * and then removed. */
		errno = ENOENT;
		e = -1;
		goto out;
	}
	e = 1;

	/* Check if we already have the interface */
	iff = if_find(ctx->ifaces, ifp->name);

	if (iff != NULL) {
		if (iff->active)
			logdebugx("%s: interface updated", iff->name);
		/* The flags and hwaddr could have changed */
		iff->flags = ifp->flags;
		iff->hwlen = ifp->hwlen;
		if (ifp->hwlen != 0)
			memcpy(iff->hwaddr, ifp->hwaddr, iff->hwlen);
	} else {
		TAILQ_REMOVE(ifs, ifp, next);
		TAILQ_INSERT_TAIL(ctx->ifaces, ifp, next);
		if (ifp->active) {
			logdebugx("%s: interface added", ifp->name);
			dhcpcd_initstate(ifp, 0);
			run_preinit(ifp);
		}
		iff = ifp;
	}

	if (action > 0) {
		if_learnaddrs(ctx, ifs, &ifaddrs);
		if (iff->active)
			dhcpcd_prestartinterface(iff);
	}

out:
	/* Free our discovered list */
	while ((ifp = TAILQ_FIRST(ifs))) {
		TAILQ_REMOVE(ifs, ifp, next);
		if_free(ifp);
	}
	free(ifs);

	return e;
}

static void
dhcpcd_handlelink(void *arg)
{
	struct dhcpcd_ctx *ctx = arg;

	if (if_handlelink(ctx) == -1) {
		if (errno == ENOBUFS || errno == ENOMEM) {
			dhcpcd_linkoverflow(ctx);
			return;
		}
		if (errno != ENOTSUP)
			logerr(__func__);
	}
}

static void
dhcpcd_checkcarrier(void *arg)
{
	struct interface *ifp = arg;
	int carrier;

	/* Check carrier here rather than setting LINK_UNKNOWN.
	 * This is because we force LINK_UNKNOWN as down for wireless which
	 * we do not want when dealing with a route socket overflow. */
	carrier = if_carrier(ifp);
	dhcpcd_handlecarrier(ifp->ctx, carrier, ifp->flags, ifp->name);
}

#ifndef SMALL
static void
dhcpcd_setlinkrcvbuf(struct dhcpcd_ctx *ctx)
{
	socklen_t socklen;

	if (ctx->link_rcvbuf == 0)
		return;

	socklen = sizeof(ctx->link_rcvbuf);
	if (setsockopt(ctx->link_fd, SOL_SOCKET,
	    SO_RCVBUF, &ctx->link_rcvbuf, socklen) == -1)
		logerr(__func__);
}
#endif

void
dhcpcd_linkoverflow(struct dhcpcd_ctx *ctx)
{
	struct if_head *ifaces;
	struct ifaddrs *ifaddrs;
	struct interface *ifp, *ifn, *ifp1;

	logerrx("route socket overflowed - learning interface state");

	/* Close the existing socket and open a new one.
	 * This is easier than draining the kernel buffer of an
	 * in-determinate size. */
	eloop_event_delete(ctx->eloop, ctx->link_fd);
	close(ctx->link_fd);
	if_closesockets_os(ctx);
	if (if_opensockets_os(ctx) == -1) {
		logerr("%s: if_opensockets", __func__);
		eloop_exit(ctx->eloop, EXIT_FAILURE);
		return;
	}
#ifndef SMALL
	dhcpcd_setlinkrcvbuf(ctx);
#endif
	eloop_event_add(ctx->eloop, ctx->link_fd, dhcpcd_handlelink, ctx);

	/* Work out the current interfaces. */
	ifaces = if_discover(ctx, &ifaddrs, ctx->ifc, ctx->ifv);
	if (ifaces == NULL) {
		logerr(__func__);
		return;
	}

	/* Punt departed interfaces */
	TAILQ_FOREACH_SAFE(ifp, ctx->ifaces, next, ifn) {
		if (if_find(ifaces, ifp->name) != NULL)
			continue;
		dhcpcd_handleinterface(ctx, -1, ifp->name);
	}

	/* Add new interfaces */
	while ((ifp = TAILQ_FIRST(ifaces)) != NULL ) {
		TAILQ_REMOVE(ifaces, ifp, next);
		ifp1 = if_find(ctx->ifaces, ifp->name);
		if (ifp1 != NULL) {
			/* If the interface already exists,
			 * check carrier state. */
			eloop_timeout_add_sec(ctx->eloop, 0,
			    dhcpcd_checkcarrier, ifp1);
			if_free(ifp);
			continue;
		}
		TAILQ_INSERT_TAIL(ctx->ifaces, ifp, next);
		if (ifp->active)
			eloop_timeout_add_sec(ctx->eloop, 0,
			    dhcpcd_prestartinterface, ifp);
	}
	free(ifaces);

	/* Update address state. */
	if_markaddrsstale(ctx->ifaces);
	if_learnaddrs(ctx, ctx->ifaces, &ifaddrs);
	if_deletestaleaddrs(ctx->ifaces);
}

void
dhcpcd_handlehwaddr(struct dhcpcd_ctx *ctx, const char *ifname,
    const void *hwaddr, uint8_t hwlen)
{
	struct interface *ifp;
	char buf[sizeof(ifp->hwaddr) * 3];

	ifp = if_find(ctx->ifaces, ifname);
	if (ifp == NULL)
		return;

	if (!if_valid_hwaddr(hwaddr, hwlen))
		hwlen = 0;

	if (hwlen > sizeof(ifp->hwaddr)) {
		errno = ENOBUFS;
		logerr("%s: %s", __func__, ifp->name);
		return;
	}

	if (ifp->hwlen == hwlen && memcmp(ifp->hwaddr, hwaddr, hwlen) == 0)
		return;

	loginfox("%s: new hardware address: %s", ifp->name,
	    hwaddr_ntoa(hwaddr, hwlen, buf, sizeof(buf)));
	ifp->hwlen = hwlen;
	memcpy(ifp->hwaddr, hwaddr, hwlen);
}

static void
if_reboot(struct interface *ifp, int argc, char **argv)
{
#ifdef INET
	unsigned long long oldopts;

	oldopts = ifp->options->options;
#endif
	script_runreason(ifp, "RECONFIGURE");
	dhcpcd_initstate1(ifp, argc, argv, 0);
#ifdef INET
	dhcp_reboot_newopts(ifp, oldopts);
#endif
#ifdef DHCP6
	dhcp6_reboot(ifp);
#endif
	dhcpcd_prestartinterface(ifp);
}

static void
reload_config(struct dhcpcd_ctx *ctx)
{
	struct if_options *ifo;

	free_globals(ctx);
	if ((ifo = read_config(ctx, NULL, NULL, NULL)) == NULL)
		return;
	add_options(ctx, NULL, ifo, ctx->argc, ctx->argv);
	/* We need to preserve these two options. */
	if (ctx->options & DHCPCD_MASTER)
		ifo->options |= DHCPCD_MASTER;
	if (ctx->options & DHCPCD_DAEMONISED)
		ifo->options |= DHCPCD_DAEMONISED;
	ctx->options = ifo->options;
	free_options(ctx, ifo);
}

static void
reconf_reboot(struct dhcpcd_ctx *ctx, int action, int argc, char **argv, int oi)
{
	int i;
	struct interface *ifp;

	TAILQ_FOREACH(ifp, ctx->ifaces, next) {
		for (i = oi; i < argc; i++) {
			if (strcmp(ifp->name, argv[i]) == 0)
				break;
		}
		if (oi != argc && i == argc)
			continue;
		if (ifp->active == IF_ACTIVE_USER) {
			if (action)
				if_reboot(ifp, argc, argv);
#ifdef INET
			else
				ipv4_applyaddr(ifp);
#endif
		} else if (i != argc) {
			ifp->active = IF_ACTIVE_USER;
			dhcpcd_initstate1(ifp, argc, argv, 0);
			run_preinit(ifp);
			dhcpcd_prestartinterface(ifp);
		}
	}
}

static void
stop_all_interfaces(struct dhcpcd_ctx *ctx, unsigned long long opts)
{
	struct interface *ifp;

	ctx->options |= DHCPCD_EXITING;
	/* Drop the last interface first */
	TAILQ_FOREACH_REVERSE(ifp, ctx->ifaces, if_head, next) {
		if (ifp->active) {
			ifp->options->options |= opts;
			if (ifp->options->options & DHCPCD_RELEASE)
				ifp->options->options &= ~DHCPCD_PERSISTENT;
			ifp->options->options |= DHCPCD_EXITING;
			stop_interface(ifp);
		}
	}
}

static void
dhcpcd_ifrenew(struct interface *ifp)
{

	if (!ifp->active)
		return;

	if (ifp->options->options & DHCPCD_LINK &&
	    ifp->carrier == LINK_DOWN)
		return;

#ifdef INET
	dhcp_renew(ifp);
#endif
#ifdef INET6
#define DHCPCD_RARENEW (DHCPCD_IPV6 | DHCPCD_IPV6RS)
	if ((ifp->options->options & DHCPCD_RARENEW) == DHCPCD_RARENEW)
		ipv6nd_startrs(ifp);
#endif
#ifdef DHCP6
	dhcp6_renew(ifp);
#endif
}

static void
dhcpcd_renew(struct dhcpcd_ctx *ctx)
{
	struct interface *ifp;

	TAILQ_FOREACH(ifp, ctx->ifaces, next) {
		dhcpcd_ifrenew(ifp);
	}
}

#ifdef USE_SIGNALS
#define sigmsg "received %s, %s"
static void
signal_cb(int sig, void *arg)
{
	struct dhcpcd_ctx *ctx = arg;
	unsigned long long opts;
	int exit_code;

	opts = 0;
	exit_code = EXIT_FAILURE;
	switch (sig) {
	case SIGINT:
		loginfox(sigmsg, "SIGINT", "stopping");
		break;
	case SIGTERM:
		loginfox(sigmsg, "SIGTERM", "stopping");
		exit_code = EXIT_SUCCESS;
		break;
	case SIGALRM:
		loginfox(sigmsg, "SIGALRM", "releasing");
		opts |= DHCPCD_RELEASE;
		exit_code = EXIT_SUCCESS;
		break;
	case SIGHUP:
		loginfox(sigmsg, "SIGHUP", "rebinding");
		reload_config(ctx);
		/* Preserve any options passed on the commandline
		 * when we were started. */
		reconf_reboot(ctx, 1, ctx->argc, ctx->argv,
		    ctx->argc - ctx->ifc);
		return;
	case SIGUSR1:
		loginfox(sigmsg, "SIGUSR1", "renewing");
		dhcpcd_renew(ctx);
		return;
	case SIGUSR2:
		loginfox(sigmsg, "SIGUSR2", "reopening log");
		logclose();
		if (logopen(ctx->logfile) == -1)
			logerr(__func__);
		return;
	case SIGPIPE:
		logwarnx("received SIGPIPE");
		return;
	default:
		logerrx("received signal %d but don't know what to do with it",
		    sig);
		return;
	}

	if (!(ctx->options & DHCPCD_TEST))
		stop_all_interfaces(ctx, opts);
	eloop_exit(ctx->eloop, exit_code);
}
#endif

static void
dhcpcd_getinterfaces(void *arg)
{
	struct fd_list *fd = arg;
	struct interface *ifp;
	size_t len;

	len = 0;
	TAILQ_FOREACH(ifp, fd->ctx->ifaces, next) {
		if (!ifp->active)
			continue;
		len++;
#ifdef INET
		if (D_STATE_RUNNING(ifp))
			len++;
#endif
#ifdef IPV4LL
		if (IPV4LL_STATE_RUNNING(ifp))
			len++;
#endif
#ifdef INET6
		if (IPV6_STATE_RUNNING(ifp))
			len++;
		if (RS_STATE_RUNNING(ifp))
			len++;
#endif
#ifdef DHCP6
		if (D6_STATE_RUNNING(ifp))
			len++;
#endif
	}
	if (write(fd->fd, &len, sizeof(len)) != sizeof(len))
		return;
	eloop_event_remove_writecb(fd->ctx->eloop, fd->fd);
	TAILQ_FOREACH(ifp, fd->ctx->ifaces, next) {
		if (!ifp->active)
			continue;
		if (send_interface(fd, ifp) == -1)
			logerr(__func__);
	}
}

int
dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd,
    int argc, char **argv)
{
	struct interface *ifp;
	unsigned long long opts;
	int opt, oi, do_reboot, do_renew;
	size_t len, l;
	char *tmp, *p;

	/* Special commands for our control socket
	 * as the other end should be blocking until it gets the
	 * expected reply we should be safely able just to change the
	 * write callback on the fd */
	if (strcmp(*argv, "--version") == 0) {
		return control_queue(fd, UNCONST(VERSION),
		    strlen(VERSION) + 1, false);
	} else if (strcmp(*argv, "--getconfigfile") == 0) {
		return control_queue(fd, UNCONST(fd->ctx->cffile),
		    strlen(fd->ctx->cffile) + 1, false);
	} else if (strcmp(*argv, "--getinterfaces") == 0) {
		eloop_event_add_w(fd->ctx->eloop, fd->fd,
		    dhcpcd_getinterfaces, fd);
		return 0;
	} else if (strcmp(*argv, "--listen") == 0) {
		fd->flags |= FD_LISTEN;
		return 0;
	}

	/* Only priviledged users can control dhcpcd via the socket. */
	if (fd->flags & FD_UNPRIV) {
		errno = EPERM;
		return -1;
	}

	/* Log the command */
	len = 1;
	for (opt = 0; opt < argc; opt++)
		len += strlen(argv[opt]) + 1;
	tmp = malloc(len);
	if (tmp == NULL)
		return -1;
	p = tmp;
	for (opt = 0; opt < argc; opt++) {
		l = strlen(argv[opt]);
		strlcpy(p, argv[opt], len);
		len -= l + 1;
		p += l;
		*p++ = ' ';
	}
	*--p = '\0';
	loginfox("control command: %s", tmp);
	free(tmp);

	optind = 0;
	oi = 0;
	opts = 0;
	do_reboot = do_renew = 0;
	while ((opt = getopt_long(argc, argv, IF_OPTS, cf_options, &oi)) != -1)
	{
		switch (opt) {
		case 'g':
			/* Assumed if below not set */
			break;
		case 'k':
			opts |= DHCPCD_RELEASE;
			break;
		case 'n':
			do_reboot = 1;
			break;
		case 'p':
			opts |= DHCPCD_PERSISTENT;
			break;
		case 'x':
			opts |= DHCPCD_EXITING;
			break;
		case 'N':
			do_renew = 1;
			break;
		}
	}

	if (opts & (DHCPCD_EXITING | DHCPCD_RELEASE)) {
		if (optind == argc) {
			stop_all_interfaces(ctx, opts);
			eloop_exit(ctx->eloop, EXIT_SUCCESS);
			return 0;
		}
		for (oi = optind; oi < argc; oi++) {
			if ((ifp = if_find(ctx->ifaces, argv[oi])) == NULL)
				continue;
			if (!ifp->active)
				continue;
			ifp->options->options |= opts;
			if (opts & DHCPCD_RELEASE)
				ifp->options->options &= ~DHCPCD_PERSISTENT;
			stop_interface(ifp);
		}
		return 0;
	}

	if (do_renew) {
		if (optind == argc) {
			dhcpcd_renew(ctx);
			return 0;
		}
		for (oi = optind; oi < argc; oi++) {
			if ((ifp = if_find(ctx->ifaces, argv[oi])) == NULL)
				continue;
			dhcpcd_ifrenew(ifp);
		}
		return 0;
	}

	reload_config(ctx);
	/* XXX: Respect initial commandline options? */
	reconf_reboot(ctx, do_reboot, argc, argv, optind - 1);
	return 0;
}

int
main(int argc, char **argv)
{
	struct dhcpcd_ctx ctx;
	struct ifaddrs *ifaddrs = NULL;
	struct if_options *ifo;
	struct interface *ifp;
	uint16_t family = 0;
	int opt, oi = 0, i;
	unsigned int logopts;
	time_t t;
	ssize_t len;
#if defined(USE_SIGNALS) || !defined(THERE_IS_NO_FORK)
	pid_t pid;
#endif
#ifdef USE_SIGNALS
	int sig = 0;
	const char *siga = NULL;
#endif

	/* Test for --help and --version */
	if (argc > 1) {
		if (strcmp(argv[1], "--help") == 0) {
			usage();
			return EXIT_SUCCESS;
		} else if (strcmp(argv[1], "--version") == 0) {
			printf(""PACKAGE" "VERSION"\n%s\n", dhcpcd_copyright);
			printf("Compiled in features:"
#ifdef INET
			" INET"
#endif
#ifdef ARP
			" ARP"
#endif
#ifdef ARPING
			" ARPing"
#endif
#ifdef IPV4LL
			" IPv4LL"
#endif
#ifdef INET6
			" INET6"
#endif
#ifdef DHCP6
			" DHCPv6"
#endif
#ifdef AUTH
			" AUTH"
#endif
			"\n");
			return EXIT_SUCCESS;
		}
	}

	memset(&ctx, 0, sizeof(ctx));

	ifo = NULL;
	ctx.cffile = CONFIG;
	ctx.control_fd = ctx.control_unpriv_fd = ctx.link_fd = -1;
	ctx.pf_inet_fd = -1;

	TAILQ_INIT(&ctx.control_fds);
#ifdef PLUGIN_DEV
	ctx.dev_fd = -1;
#endif
#ifdef INET
	ctx.udp_fd = -1;
#endif
	rt_init(&ctx);

	logopts = LOGERR_ERR|LOGERR_LOG|LOGERR_LOG_DATE|LOGERR_LOG_PID;
	i = 0;
	while ((opt = getopt_long(argc, argv,
	    ctx.options & DHCPCD_PRINT_PIDFILE ? NOERR_IF_OPTS : IF_OPTS,
	    cf_options, &oi)) != -1)
	{
		switch (opt) {
		case '4':
			family = AF_INET;
			break;
		case '6':
			family = AF_INET6;
			break;
		case 'f':
			ctx.cffile = optarg;
			break;
		case 'j':
			free(ctx.logfile);
			ctx.logfile = strdup(optarg);
			break;
#ifdef USE_SIGNALS
		case 'k':
			sig = SIGALRM;
			siga = "ALRM";
			break;
		case 'n':
			sig = SIGHUP;
			siga = "HUP";
			break;
		case 'g':
		case 'p':
			/* Force going via command socket as we're
			 * out of user definable signals. */
			i = 4;
			break;
		case 'q':
			logopts |= LOGERR_QUIET;
			break;
		case 'x':
			sig = SIGTERM;
			siga = "TERM";
			break;
		case 'N':
			sig = SIGUSR1;
			siga = "USR1";
			break;
#endif
		case 'P':
			ctx.options |= DHCPCD_PRINT_PIDFILE;
			logopts &= ~(LOGERR_LOG | LOGERR_ERR);
			break;
		case 'T':
			i = 1;
			logopts &= ~LOGERR_LOG;
			break;
		case 'U':
			i = 3;
			break;
		case 'V':
			i = 2;
			break;
		case '?':
			if (ctx.options & DHCPCD_PRINT_PIDFILE)
				continue;
			usage();
			goto exit_failure;
		}
	}

	logsetopts(logopts);
	logopen(ctx.logfile);

	ctx.argv = argv;
	ctx.argc = argc;
	ctx.ifc = argc - optind;
	ctx.ifv = argv + optind;

	ifo = read_config(&ctx, NULL, NULL, NULL);
	if (ifo == NULL) {
		if (ctx.options & DHCPCD_PRINT_PIDFILE)
			goto printpidfile;
		goto exit_failure;
	}
	opt = add_options(&ctx, NULL, ifo, argc, argv);
	if (opt != 1) {
		if (ctx.options & DHCPCD_PRINT_PIDFILE)
			goto printpidfile;
		if (opt == 0)
			usage();
		goto exit_failure;
	}
	if (i == 2) {
		printf("Interface options:\n");
		if (optind == argc - 1) {
			free_options(&ctx, ifo);
			ifo = read_config(&ctx, argv[optind], NULL, NULL);
			if (ifo == NULL)
				goto exit_failure;
			add_options(&ctx, NULL, ifo, argc, argv);
		}
		if_printoptions();
#ifdef INET
		if (family == 0 || family == AF_INET) {
			printf("\nDHCPv4 options:\n");
			dhcp_printoptions(&ctx,
			    ifo->dhcp_override, ifo->dhcp_override_len);
		}
#endif
#ifdef INET6
		if (family == 0 || family == AF_INET6) {
			printf("\nND options:\n");
			ipv6nd_printoptions(&ctx,
			    ifo->nd_override, ifo->nd_override_len);
#ifdef DHCP6
			printf("\nDHCPv6 options:\n");
			dhcp6_printoptions(&ctx,
			    ifo->dhcp6_override, ifo->dhcp6_override_len);
#endif
		}
#endif
		goto exit_success;
	}
	ctx.options |= ifo->options;
	if (i == 1 || i == 3) {
		if (i == 1)
			ctx.options |= DHCPCD_TEST;
		else
			ctx.options |= DHCPCD_DUMPLEASE;
		ctx.options |= DHCPCD_PERSISTENT;
		ctx.options &= ~DHCPCD_DAEMONISE;
	}

#ifdef THERE_IS_NO_FORK
	ctx.options &= ~DHCPCD_DAEMONISE;
#endif

	if (ctx.options & DHCPCD_DEBUG)
		logsetopts(logopts | LOGERR_DEBUG);

	if (!(ctx.options & (DHCPCD_TEST | DHCPCD_DUMPLEASE))) {
printpidfile:
		/* If we have any other args, we should run as a single dhcpcd
		 *  instance for that interface. */
		if (optind == argc - 1 && !(ctx.options & DHCPCD_MASTER)) {
			const char *per;
			const char *ifname;

			ifname = *ctx.ifv;
			if (ifname == NULL || strlen(ifname) > IF_NAMESIZE) {
				errno = ifname == NULL ? EINVAL : E2BIG;
				logerr("%s: ", ifname);
				goto exit_failure;
			}
			/* Allow a dhcpcd interface per address family */
			switch(family) {
			case AF_INET:
				per = "-4";
				break;
			case AF_INET6:
				per = "-6";
				break;
			default:
				per = "";
			}
			snprintf(ctx.pidfile, sizeof(ctx.pidfile),
			    PIDFILE, "-", ifname, per);
		} else {
			snprintf(ctx.pidfile, sizeof(ctx.pidfile),
			    PIDFILE, "", "", "");
			ctx.options |= DHCPCD_MASTER;
		}
		if (ctx.options & DHCPCD_PRINT_PIDFILE) {
			printf("%s\n", ctx.pidfile);
			goto exit_success;
		}
	}

	if (chdir("/") == -1)
		logerr("%s: chdir `/'", __func__);

	/* Freeing allocated addresses from dumping leases can trigger
	 * eloop removals as well, so init here. */
	if ((ctx.eloop = eloop_new()) == NULL) {
		logerr("%s: eloop_init", __func__);
		goto exit_failure;
	}
#ifdef USE_SIGNALS
	/* Save signal mask, block and redirect signals to our handler */
	if (eloop_signal_set_cb(ctx.eloop,
	    dhcpcd_signals, dhcpcd_signals_len,
	    signal_cb, &ctx) == -1)
	{
		logerr("%s: eloop_signal_set_cb", __func__);
		goto exit_failure;
	}
	if (eloop_signal_mask(ctx.eloop, &ctx.sigset) == -1) {
		logerr("%s: eloop_signal_mask", __func__);
		goto exit_failure;
	}
#endif

	if (ctx.options & DHCPCD_DUMPLEASE) {
		/* Open sockets so we can dump something about
		 * valid interfaces. */
		if (if_opensockets(&ctx) == -1) {
			logerr("%s: if_opensockets", __func__);
			goto exit_failure;
		}
		if (optind != argc) {
			/* We need to try and find the interface so we can load
			 * the hardware address to compare automated IAID */
			ctx.ifaces = if_discover(&ctx, &ifaddrs,
			    argc - optind, argv + optind);
		} else {
			if ((ctx.ifaces = malloc(sizeof(*ctx.ifaces))) != NULL)
				TAILQ_INIT(ctx.ifaces);
		}
		if (ctx.ifaces == NULL) {
			logerr("%s: if_discover", __func__);
			goto exit_failure;
		}
		ifp = if_find(ctx.ifaces, argv[optind]);
		if (ifp == NULL) {
			ifp = calloc(1, sizeof(*ifp));
			if (ifp == NULL) {
				logerr(__func__);
				goto exit_failure;
			}
			if (optind != argc)
				strlcpy(ctx.pidfile, argv[optind],
				    sizeof(ctx.pidfile));
			ifp->ctx = &ctx;
			TAILQ_INSERT_HEAD(ctx.ifaces, ifp, next);
			if (family == 0) {
				if (ctx.pidfile[0] != '\0' &&
				    ctx.pidfile[strlen(ctx.pidfile) - 1] == '6')
					family = AF_INET6;
				else
					family = AF_INET;
			}
		}
		configure_interface(ifp, ctx.argc, ctx.argv, 0);
		i = 0;
		if (family == 0 || family == AF_INET) {
#ifdef INET
			if (dhcp_dump(ifp) == -1)
				i = -1;
#else
			if (family == AF_INET)
				logerrx("No INET support");
#endif
		}
		if (family == 0 || family == AF_INET6) {
#ifdef DHCP6
			if (dhcp6_dump(ifp) == -1)
				i = -1;
#else
			if (family == AF_INET6)
				logerrx("No DHCP6 support");
#endif
		}
		if (i == -1)
			goto exit_failure;
		goto exit_success;
	}

#ifdef USE_SIGNALS
	/* Test against siga instead of sig to avoid gcc
	 * warning about a bogus potential signed overflow.
	 * The end result will be the same. */
	if ((siga == NULL || i == 4 || ctx.ifc != 0) &&
	    !(ctx.options & DHCPCD_TEST))
	{
#endif
		if (!(ctx.options & DHCPCD_MASTER))
			ctx.control_fd = control_open(argv[optind]);
		if (ctx.control_fd == -1)
			ctx.control_fd = control_open(NULL);
		if (ctx.control_fd != -1) {
			loginfox("sending commands to master dhcpcd process");
			len = control_send(&ctx, argc, argv);
			control_close(&ctx);
			if (len > 0) {
				logdebugx("send OK");
				goto exit_success;
			} else {
				logerr("%s: control_send", __func__);
				goto exit_failure;
			}
		} else {
			if (errno != ENOENT)
				logerr("%s: control_open", __func__);
		}
#ifdef USE_SIGNALS
	}
#endif

#ifdef USE_SIGNALS
	if (sig != 0) {
		pid = pidfile_read(ctx.pidfile);
		if (pid != 0 && pid != -1)
			loginfox("sending signal %s to pid %d", siga, pid);
		if (pid == 0 || pid == -1 || kill(pid, sig) != 0) {
			if (sig != SIGHUP && sig != SIGUSR1 && errno != EPERM)
				logerrx(PACKAGE" not running");
			if (pid != 0 && pid != -1 && errno != ESRCH) {
				logerr("kill");
				goto exit_failure;
			}
			unlink(ctx.pidfile);
			if (sig != SIGHUP && sig != SIGUSR1)
				goto exit_failure;
		} else {
			struct timespec ts;

			if (sig == SIGHUP || sig == SIGUSR1)
				goto exit_success;
			/* Spin until it exits */
			loginfox("waiting for pid %d to exit", pid);
			ts.tv_sec = 0;
			ts.tv_nsec = 100000000; /* 10th of a second */
			for(i = 0; i < 100; i++) {
				nanosleep(&ts, NULL);
				if (pidfile_read(ctx.pidfile) == -1)
					goto exit_success;
			}
			logerrx("pid %d failed to exit", pid);
			goto exit_failure;
		}
	}

	if (!(ctx.options & DHCPCD_TEST)) {
		/* Ensure we have the needed directories */
		if (mkdir(RUNDIR, 0755) == -1 && errno != EEXIST)
			logerr("%s: mkdir `%s'", __func__, RUNDIR);
		if (mkdir(DBDIR, 0755) == -1 && errno != EEXIST)
			logerr("%s: mkdir `%s'", __func__, DBDIR);

		if ((pid = pidfile_lock(ctx.pidfile)) != 0) {
			if (pid == -1)
				logerr("%s: pidfile_lock", __func__);
			else
				logerrx(PACKAGE
				    " already running on pid %d (%s)",
				    pid, ctx.pidfile);
			goto exit_failure;
		}
	}

	if (ctx.options & DHCPCD_MASTER) {
		if (control_start(&ctx, NULL) == -1)
			logerr("%s: control_start", __func__);
	}
#else
	if (control_start(&ctx,
	    ctx.options & DHCPCD_MASTER ? NULL : argv[optind]) == -1)
	{
		logerr("%s: control_start", __func__);
		goto exit_failure;
	}
#endif

	logdebugx(PACKAGE "-" VERSION " starting");
	ctx.options |= DHCPCD_STARTED;

	setproctitle("%s%s%s",
	    ctx.options & DHCPCD_MASTER ? "[master]" : argv[optind],
	    ctx.options & DHCPCD_IPV4 ? " [ip4]" : "",
	    ctx.options & DHCPCD_IPV6 ? " [ip6]" : "");

#ifdef BSD
	/* Disable the kernel RTADV sysctl as early as possible. */
	if (ctx.options & DHCPCD_IPV6 && ctx.options & DHCPCD_IPV6RS)
		if_disable_rtadv();
#endif

	if (if_opensockets(&ctx) == -1) {
		logerr("%s: if_opensockets", __func__);
		goto exit_failure;
	}
#ifndef SMALL
	dhcpcd_setlinkrcvbuf(&ctx);
#endif

	/* When running dhcpcd against a single interface, we need to retain
	 * the old behaviour of waiting for an IP address */
	if (ctx.ifc == 1 && !(ctx.options & DHCPCD_BACKGROUND))
		ctx.options |= DHCPCD_WAITIP;

	/* Start handling kernel messages for interfaces, addresses and
	 * routes. */
	eloop_event_add(ctx.eloop, ctx.link_fd, dhcpcd_handlelink, &ctx);

	/* Start any dev listening plugin which may want to
	 * change the interface name provided by the kernel */
	if ((ctx.options & (DHCPCD_MASTER | DHCPCD_DEV)) ==
	    (DHCPCD_MASTER | DHCPCD_DEV))
		dev_start(&ctx);

	ctx.ifaces = if_discover(&ctx, &ifaddrs, ctx.ifc, ctx.ifv);
	if (ctx.ifaces == NULL) {
		logerr("%s: if_discover", __func__);
		goto exit_failure;
	}
	for (i = 0; i < ctx.ifc; i++) {
		if ((ifp = if_find(ctx.ifaces, ctx.ifv[i])) == NULL ||
		    !ifp->active)
			logerrx("%s: interface not found or invalid",
			    ctx.ifv[i]);
	}
	TAILQ_FOREACH(ifp, ctx.ifaces, next) {
		if (ifp->active == IF_ACTIVE_USER)
			break;
	}
	if (ifp == NULL) {
		if (ctx.ifc == 0) {
			int loglevel;

			loglevel = ctx.options & DHCPCD_INACTIVE ?
			    LOG_DEBUG : LOG_ERR;
			logmessage(loglevel, "no valid interfaces found");
		} else
			goto exit_failure;
		if (!(ctx.options & DHCPCD_LINK)) {
			logerrx("aborting as link detection is disabled");
			goto exit_failure;
		}
	}

	TAILQ_FOREACH(ifp, ctx.ifaces, next) {
		if (ifp->active)
			dhcpcd_initstate1(ifp, argc, argv, 0);
	}
	if_learnaddrs(&ctx, ctx.ifaces, &ifaddrs);

	if (ctx.options & DHCPCD_BACKGROUND && dhcpcd_daemonise(&ctx))
		goto exit_success;

	opt = 0;
	TAILQ_FOREACH(ifp, ctx.ifaces, next) {
		if (ifp->active) {
			run_preinit(ifp);
			if (!(ifp->options->options & DHCPCD_LINK) ||
			    ifp->carrier != LINK_DOWN)
				opt = 1;
		}
	}

	if (!(ctx.options & DHCPCD_BACKGROUND)) {
		if (ctx.options & DHCPCD_MASTER)
			t = ifo->timeout;
		else {
			t = 0;
			TAILQ_FOREACH(ifp, ctx.ifaces, next) {
				if (ifp->active) {
					t = ifp->options->timeout;
					break;
				}
			}
		}
		if (opt == 0 &&
		    ctx.options & DHCPCD_LINK &&
		    !(ctx.options & DHCPCD_WAITIP))
		{
			int loglevel;

			loglevel = ctx.options & DHCPCD_INACTIVE ?
			    LOG_DEBUG : LOG_WARNING;
			logmessage(loglevel, "no interfaces have a carrier");
			if (dhcpcd_daemonise(&ctx))
				goto exit_success;
		} else if (t > 0 &&
		    /* Test mode removes the daemonise bit, so check for both */
		    ctx.options & (DHCPCD_DAEMONISE | DHCPCD_TEST))
		{
			eloop_timeout_add_sec(ctx.eloop, t,
			    handle_exit_timeout, &ctx);
		}
	}
	free_options(&ctx, ifo);
	ifo = NULL;

	TAILQ_FOREACH(ifp, ctx.ifaces, next) {
		if (ifp->active)
			eloop_timeout_add_sec(ctx.eloop, 0,
			    dhcpcd_prestartinterface, ifp);
	}

	i = eloop_start(ctx.eloop, &ctx.sigset);
	if (i < 0) {
		logerr("%s: eloop_start", __func__);
		goto exit_failure;
	}
	goto exit1;

exit_success:
	i = EXIT_SUCCESS;
	goto exit1;

exit_failure:
	i = EXIT_FAILURE;

exit1:
	if (ifaddrs != NULL)
		freeifaddrs(ifaddrs);
	if (control_stop(&ctx) == -1)
		logerr("%s: control_stop", __func__);
	/* Free memory and close fd's */
	if (ctx.ifaces) {
		while ((ifp = TAILQ_FIRST(ctx.ifaces))) {
			TAILQ_REMOVE(ctx.ifaces, ifp, next);
			if_free(ifp);
		}
		free(ctx.ifaces);
		ctx.ifaces = NULL;
	}
	free_options(&ctx, ifo);
#ifdef HAVE_OPEN_MEMSTREAM
	if (ctx.script_fp)
		fclose(ctx.script_fp);
#endif
	free(ctx.script_buf);
	free(ctx.script_env);
	rt_dispose(&ctx);
	free(ctx.duid);
	if (ctx.link_fd != -1) {
		eloop_event_delete(ctx.eloop, ctx.link_fd);
		close(ctx.link_fd);
	}
	if_closesockets(&ctx);
	free_globals(&ctx);
#ifdef INET6
	ipv6_ctxfree(&ctx);
#endif
	dev_stop(&ctx);
	eloop_free(ctx.eloop);

	if (ctx.options & DHCPCD_STARTED && !(ctx.options & DHCPCD_FORKED))
		loginfox(PACKAGE " exited");
	logclose();
	free(ctx.logfile);
#ifdef SETPROCTITLE_H
	setproctitle_free();
#endif
#ifdef USE_SIGNALS
	if (ctx.options & DHCPCD_FORKED)
		_exit(i); /* so atexit won't remove our pidfile */
#endif
	return i;
}