path: root/sbin/dhclient/dhclient.c

/*	$OpenBSD: dhclient.c,v 1.12 2004/02/24 12:34:26 henning Exp $	*/

/* DHCP Client. */

/*
 * Copyright 2004 Henning Brauer <henning@openbsd.org>
 * Copyright (c) 1995, 1996, 1997, 1998, 1999
 * The Internet Software Consortium.    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.
 * 3. Neither the name of The Internet Software Consortium nor the names
 *    of its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM 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 INTERNET SOFTWARE CONSORTIUM 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.
 *
 * This software has been written for the Internet Software Consortium
 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
 * Enterprises.  To learn more about the Internet Software Consortium,
 * see ``http://www.vix.com/isc''.  To learn more about Vixie
 * Enterprises, see ``http://www.vix.com''.
 *
 * This client was substantially modified and enhanced by Elliot Poger
 * for use on Linux while he was working on the MosquitoNet project at
 * Stanford.
 *
 * The current version owes much to Elliot's Linux enhancements, but
 * was substantially reorganized and partially rewritten by Ted Lemon
 * so as to use the same networking framework that the Internet Software
 * Consortium DHCP server uses.   Much system-specific configuration code
 * was moved into a shell script so that as support for more operating
 * systems is added, it will not be necessary to port and maintain
 * system-specific configuration code to these operating systems - instead,
 * the shell script can invoke the native tools to accomplish the same
 * purpose.
 */

#include "dhcpd.h"

#define	PERIOD 0x2e
#define	hyphenchar(c) ((c) == 0x2d)
#define	bslashchar(c) ((c) == 0x5c)
#define	periodchar(c) ((c) == PERIOD)
#define	asterchar(c) ((c) == 0x2a)
#define	alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) || \
	    ((c) >= 0x61 && (c) <= 0x7a))
#define	digitchar(c) ((c) >= 0x30 && (c) <= 0x39)

#define	borderchar(c) (alphachar(c) || digitchar(c))
#define	middlechar(c) (borderchar(c) || hyphenchar(c))
#define	domainchar(c) ((c) > 0x20 && (c) < 0x7f)

#define	CLIENT_PATH "PATH=/usr/bin:/usr/sbin:/bin:/sbin"

time_t cur_time;
time_t default_lease_time = 43200; /* 12 hours... */
time_t max_lease_time = 86400; /* 24 hours... */
struct tree_cache *global_options[256];

char *path_dhclient_conf = _PATH_DHCLIENT_CONF;
char *path_dhclient_db = _PATH_DHCLIENT_DB;
char *path_dhclient_pid = _PATH_DHCLIENT_PID;

int interfaces_requested = 0;

int log_perror = 1;

struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } };
struct iaddr iaddr_any = { 4, { 0, 0, 0, 0 } };
struct in_addr inaddr_any;
struct sockaddr_in sockaddr_broadcast;

/*
 * ASSERT_STATE() does nothing now; it used to be
 * assert (state_is == state_shouldbe).
 */
#define ASSERT_STATE(state_is, state_shouldbe) {}

u_int16_t local_port;
u_int16_t remote_port;
int log_priority;
int no_daemon;
int save_scripts;
int onetry = 0;
int unknown_ok = 1;

void	usage(void);

static int check_option(struct client_lease *l, int option);

static int ipv4addrs(char * buf);

static int res_hnok(const char *dn);

char *option_as_string(unsigned int code, unsigned char *data, int len);

int routefd;

struct interface_info *
isours(u_int16_t index)
{
	struct interface_info *ip;

	for (ip = interfaces; ip; ip = ip->next)
		if (index == ip->index)
			return (ip);

	return (NULL);
}

#define	ROUNDUP(a) \
	    ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
#define	ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))

int
findproto(char *cp, int n)
{
	struct sockaddr *sa;
	int i;

	if (n == 0)
		return -1;
	for (i = 1; i; i <<= 1) {
		if (i & n) {
			sa = (struct sockaddr *)cp;
			switch (i) {
			case RTA_IFA:
			case RTA_DST:
			case RTA_GATEWAY:
			case RTA_NETMASK:
				if (sa->sa_family == AF_INET)
					return AF_INET;
				if (sa->sa_family == AF_INET6)
					return AF_INET6;
				break;
			case RTA_IFP:
				break;
			}
			ADVANCE(cp, sa);
		}
	}
	return (-1);
}

void
routehandler(struct protocol *p)
{
	char msg[2048];
	struct rt_msghdr *rtm;
	struct if_msghdr *ifm;
	struct ifa_msghdr *ifam;
	struct interface_info *ip;
	ssize_t n;

	n = read(routefd, &msg, sizeof(msg));
	rtm = (struct rt_msghdr *)msg;
	if (n < sizeof(rtm->rtm_msglen) || n < rtm->rtm_msglen ||
	    rtm->rtm_version != RTM_VERSION)
		return;

	switch (rtm->rtm_type) {
	case RTM_NEWADDR:
		ifam = (struct ifa_msghdr *)rtm;
		if ((ip = isours(ifam->ifam_index)) == NULL)
			break;
		if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
			break;
		/* goto die; */
		break;
	case RTM_DELADDR:
		ifam = (struct ifa_msghdr *)rtm;
		if ((ip = isours(ifam->ifam_index)) == NULL)
			break;
		if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
			break;
		goto die;
		break;
	case RTM_IFINFO:
		ifm = (struct if_msghdr *)rtm;
		if ((ip = isours(ifm->ifm_index)) == NULL)
			break;
		if ((rtm->rtm_flags & RTF_UP) == 0)
			goto die;
		break;
	default:
		break;
	}
	return;

die:
	script_init(ip, "FAIL", NULL);
	if (ip->client->alias)
		script_write_params(ip, "alias_", ip->client->alias);
	script_go(ip);
	exit(1);
}

int
main(int argc, char *argv[])
{
	extern char		*__progname;
	struct servent		*ent;
	struct interface_info	*ip = NULL;
	int			 ch, fd, seed, quiet = 0;

	/* Initially, log errors to stderr as well as to syslogd. */
	openlog(__progname, LOG_NDELAY, DHCPD_LOG_FACILITY);
	setlogmask(LOG_UPTO(LOG_INFO));

	while ((ch = getopt(argc, argv, "c:dDl:qu")) != -1)
		switch (ch) {
		case 'c':
			path_dhclient_conf = optarg;
			break;
		case 'd':
			no_daemon = 1;
			break;
		case 'D':
			save_scripts = 1;
			break;
		case 'l':
			path_dhclient_db = optarg;
			break;
		case 'q':
			quiet = 1;
			quiet_interface_discovery = 1;
			break;
		case 'u':
			unknown_ok = 0;
			break;
		default:
			usage();
		}

	argc -= optind;
	argv += optind;

	if (argc != 1)
		usage();

	if ((ip = calloc(1, sizeof(struct interface_info))) == NULL)
		error("calloc");
	strlcpy(ip->name, argv[0], IFNAMSIZ);
	ip->flags = INTERFACE_REQUESTED;
	interfaces_requested = 1;
	interfaces = ip;

	if (quiet)
		log_perror = 0;

	/* Default to the DHCP/BOOTP port. */
	if (!local_port) {
		ent = getservbyname("dhcpc", "udp");
		if (!ent)
			local_port = htons(68);
		else
			local_port = ent->s_port;
	}
	remote_port = htons(ntohs(local_port) - 1);	/* XXX */

	/* Get the current time... */
	time(&cur_time);

	memset(&sockaddr_broadcast, 0, sizeof(sockaddr_broadcast));
	sockaddr_broadcast.sin_family = AF_INET;
	sockaddr_broadcast.sin_port = remote_port;
	sockaddr_broadcast.sin_addr.s_addr = INADDR_BROADCAST;
	sockaddr_broadcast.sin_len = sizeof(sockaddr_broadcast);
	inaddr_any.s_addr = INADDR_ANY;

	/* Parse the dhclient.conf file. */
	read_client_conf();

	/* Lock the leases file */
	fd = open(path_dhclient_db, O_RDONLY | O_EXLOCK | O_CREAT, 0);
	if (fd < 0)
		error("can't open and lock %s: %m", path_dhclient_db);

	/* Parse the lease database. */
	read_client_leases();

	/* Rewrite the lease database... */
	rewrite_client_leases();

	/* Close and unlock */
	close(fd);

	if (!interfaces_requested)
		error("no interface given");

	if (interface_link_status(ip->name)) {
		script_init(ip, "PREINIT", NULL);
		if (ip->client->alias)
			script_write_params(ip, "alias_", ip->client->alias);
		script_go(ip);
	} else
		error("no link on interface %s", ip->name);

	routefd = socket(PF_ROUTE, SOCK_RAW, 0);
	if (routefd != -1)
		add_protocol("AF_ROUTE", routefd, routehandler, interfaces);

	/* set up the interfaces. */
	discover_interfaces(DISCOVER_REQUESTED);

	/* Make up a seed for the random number generator from current
	   time plus the sum of the last four bytes of each
	   interface's hardware address interpreted as an integer.
	   Not much entropy, but we're booting, so we're not likely to
	   find anything better. */
	seed = 0; /* Unfortunately, what's on the stack isn't random. :') */
	for (ip = interfaces; ip; ip = ip->next) {
		int junk;
		memcpy(&junk, &ip->hw_address.haddr[ip->hw_address.hlen -
		    sizeof(seed)], sizeof(seed));
		seed += junk;
	}
	srandom(seed + cur_time);

	/* Start a configuration state machine for each interface. */
	for (ip = interfaces; ip; ip = ip->next) {
		ip->client->state = S_INIT;
		state_reboot(ip);
	}

	/* Set up the bootp packet handler... */
	bootp_packet_handler = do_packet;

	/* Start dispatching packets and timeouts... */
	dispatch();

	/*NOTREACHED*/
	return (0);
}

void
usage(void)
{
	extern char	*__progname;

	fprintf(stderr, "usage: %s [-dDqu] ", __progname);
	fprintf(stderr, "[-c conffile] [-l leasefile] interface\n");
	exit(1);
}

void
cleanup(void)
{
}

/*
 * Individual States:
 *
 * Each routine is called from the dhclient_state_machine() in one of
 * these conditions:
 * -> entering INIT state
 * -> recvpacket_flag == 0: timeout in this state
 * -> otherwise: received a packet in this state
 *
 * Return conditions as handled by dhclient_state_machine():
 * Returns 1, sendpacket_flag = 1: send packet, reset timer.
 * Returns 1, sendpacket_flag = 0: just reset the timer (wait for a milestone).
 * Returns 0: finish the nap which was interrupted for no good reason.
 *
 * Several per-interface variables are used to keep track of the process:
 *   active_lease: the lease that is being used on the interface
 *                 (null pointer if not configured yet).
 *   offered_leases: leases corresponding to DHCPOFFER messages that have
 *                   been sent to us by DHCP servers.
 *   acked_leases: leases corresponding to DHCPACK messages that have been
 *                 sent to us by DHCP servers.
 *   sendpacket: DHCP packet we're trying to send.
 *   destination: IP address to send sendpacket to
 * In addition, there are several relevant per-lease variables.
 *   T1_expiry, T2_expiry, lease_expiry: lease milestones
 * In the active lease, these control the process of renewing the lease;
 * In leases on the acked_leases list, this simply determines when we
 * can no longer legitimately use the lease.
 */

void
state_reboot(void *ipp)
{
	struct interface_info *ip = ipp;

	/* If we don't remember an active lease, go straight to INIT. */
	if (!ip->client->active || ip->client->active->is_bootp) {
		state_init(ip);
		return;
	}

	/* We are in the rebooting state. */
	ip->client->state = S_REBOOTING;

	/* make_request doesn't initialize xid because it normally comes
	   from the DHCPDISCOVER, but we haven't sent a DHCPDISCOVER,
	   so pick an xid now. */
	ip->client->xid = random();

	/* Make a DHCPREQUEST packet, and set appropriate per-interface
	   flags. */
	make_request(ip, ip->client->active);
	ip->client->destination = iaddr_broadcast;
	ip->client->first_sending = cur_time;
	ip->client->interval = ip->client->config->initial_interval;

	/* Zap the medium list... */
	ip->client->medium = NULL;

	/* Send out the first DHCPREQUEST packet. */
	send_request(ip);
}

/* Called when a lease has completely expired and we've been unable to
   renew it. */

void
state_init(void *ipp)
{
	struct interface_info *ip = ipp;

	ASSERT_STATE(state, S_INIT);

	/* Make a DHCPDISCOVER packet, and set appropriate per-interface
	   flags. */
	make_discover(ip, ip->client->active);
	ip->client->xid = ip->client->packet.xid;
	ip->client->destination = iaddr_broadcast;
	ip->client->state = S_SELECTING;
	ip->client->first_sending = cur_time;
	ip->client->interval = ip->client->config->initial_interval;

	/* Add an immediate timeout to cause the first DHCPDISCOVER packet
	   to go out. */
	send_discover(ip);
}

/* state_selecting is called when one or more DHCPOFFER packets have been
   received and a configurable period of time has passed. */

void
state_selecting(void *ipp)
{
	struct interface_info *ip = ipp;

	struct client_lease *lp, *next, *picked;

	ASSERT_STATE(state, S_SELECTING);

	/* Cancel state_selecting and send_discover timeouts, since either
	   one could have got us here. */
	cancel_timeout(state_selecting, ip);
	cancel_timeout(send_discover, ip);

	/* We have received one or more DHCPOFFER packets.   Currently,
	   the only criterion by which we judge leases is whether or
	   not we get a response when we arp for them. */
	picked = NULL;
	for (lp = ip->client->offered_leases; lp; lp = next) {
		next = lp->next;

		/* Check to see if we got an ARPREPLY for the address
		   in this particular lease. */
		if (!picked) {
			script_init(ip, "ARPCHECK", lp->medium);
			script_write_params(ip, "check_", lp);

			/* If the ARPCHECK code detects another
			   machine using the offered address, it exits
			   nonzero.  We need to send a DHCPDECLINE and
			   toss the lease. */
			if (script_go(ip)) {
				make_decline(ip, lp);
				send_decline(ip);
				goto freeit;
			}
			picked = lp;
			picked->next = NULL;
		} else {
freeit:
			free_client_lease(lp);
		}
	}
	ip->client->offered_leases = NULL;

	/* If we just tossed all the leases we were offered, go back
	   to square one. */
	if (!picked) {
		ip->client->state = S_INIT;
		state_init(ip);
		return;
	}

	/* If it was a BOOTREPLY, we can just take the address right now. */
	if (!picked->options[DHO_DHCP_MESSAGE_TYPE].len) {
		ip->client->new = picked;

		/* Make up some lease expiry times
		   XXX these should be configurable. */
		ip->client->new->expiry = cur_time + 12000;
		ip->client->new->renewal += cur_time + 8000;
		ip->client->new->rebind += cur_time + 10000;

		ip->client->state = S_REQUESTING;

		/* Bind to the address we received. */
		bind_lease(ip);
		return;
	}

	/* Go to the REQUESTING state. */
	ip->client->destination = iaddr_broadcast;
	ip->client->state = S_REQUESTING;
	ip->client->first_sending = cur_time;
	ip->client->interval = ip->client->config->initial_interval;

	/* Make a DHCPREQUEST packet from the lease we picked. */
	make_request(ip, picked);
	ip->client->xid = ip->client->packet.xid;

	/* Toss the lease we picked - we'll get it back in a DHCPACK. */
	free_client_lease(picked);

	/* Add an immediate timeout to send the first DHCPREQUEST packet. */
	send_request(ip);
}

/* state_requesting is called when we receive a DHCPACK message after
   having sent out one or more DHCPREQUEST packets. */

void
dhcpack(struct packet *packet)
{
	struct interface_info *ip = packet->interface;
	struct client_lease *lease;

	/* If we're not receptive to an offer right now, or if the offer
	   has an unrecognizable transaction id, then just drop it. */
	if (packet->interface->client->xid != packet->raw->xid ||
	    (packet->interface->hw_address.hlen != packet->raw->hlen) ||
	    (memcmp(packet->interface->hw_address.haddr,
	    packet->raw->chaddr, packet->raw->hlen))) {
#ifdef DEBUG
		debug("DHCPACK in wrong transaction.");
#endif
		return;
	}

	if (ip->client->state != S_REBOOTING &&
	    ip->client->state != S_REQUESTING &&
	    ip->client->state != S_RENEWING &&
	    ip->client->state != S_REBINDING) {
#ifdef DEBUG
		debug("DHCPACK in wrong state.");
#endif
		return;
	}

	note("DHCPACK from %s", piaddr(packet->client_addr));

	lease = packet_to_lease(packet);
	if (!lease) {
		note("packet_to_lease failed.");
		return;
	}

	ip->client->new = lease;

	/* Stop resending DHCPREQUEST. */
	cancel_timeout(send_request, ip);

	/* Figure out the lease time. */
	if (ip->client->new->options[DHO_DHCP_LEASE_TIME].data)
		ip->client->new->expiry = getULong(
		    ip->client->new->options[DHO_DHCP_LEASE_TIME].data);
	else
		ip->client->new->expiry = default_lease_time;
	/* A number that looks negative here is really just very large,
	   because the lease expiry offset is unsigned. */
	if (ip->client->new->expiry < 0)
		ip->client->new->expiry = TIME_MAX;

	/* Take the server-provided renewal time if there is one;
	   otherwise figure it out according to the spec. */
	if (ip->client->new->options[DHO_DHCP_RENEWAL_TIME].len)
		ip->client->new->renewal = getULong(
		    ip->client->new->options[DHO_DHCP_RENEWAL_TIME].data);
	else
		ip->client->new->renewal = ip->client->new->expiry / 2;

	/* Same deal with the rebind time. */
	if (ip->client->new->options[DHO_DHCP_REBINDING_TIME].len)
		ip->client->new->rebind = getULong(
		    ip->client->new->options[DHO_DHCP_REBINDING_TIME].data);
	else
		ip->client->new->rebind = ip->client->new->renewal +
		    ip->client->new->renewal / 2 + ip->client->new->renewal / 4;

	ip->client->new->expiry += cur_time;
	/* Lease lengths can never be negative. */
	if (ip->client->new->expiry < cur_time)
		ip->client->new->expiry = TIME_MAX;
	ip->client->new->renewal += cur_time;
	if (ip->client->new->renewal < cur_time)
		ip->client->new->renewal = TIME_MAX;
	ip->client->new->rebind += cur_time;
	if (ip->client->new->rebind < cur_time)
		ip->client->new->rebind = TIME_MAX;

	bind_lease(ip);
}

void
bind_lease(struct interface_info *ip)
{
	/* Remember the medium. */
	ip->client->new->medium = ip->client->medium;

	/* Write out the new lease. */
	write_client_lease(ip, ip->client->new, 0);

	/* Run the client script with the new parameters. */
	script_init(ip, (ip->client->state == S_REQUESTING ? "BOUND" :
	    (ip->client->state == S_RENEWING ? "RENEW" :
	    (ip->client->state == S_REBOOTING ? "REBOOT" : "REBIND"))),
	    ip->client->new->medium);
	if (ip->client->active && ip->client->state != S_REBOOTING)
		script_write_params(ip, "old_", ip->client->active);
	script_write_params(ip, "new_", ip->client->new);
	if (ip->client->alias)
		script_write_params(ip, "alias_", ip->client->alias);
	script_go(ip);

	/* Replace the old active lease with the new one. */
	if (ip->client->active)
		free_client_lease(ip->client->active);
	ip->client->active = ip->client->new;
	ip->client->new = NULL;

	/* Set up a timeout to start the renewal process. */
	add_timeout(ip->client->active->renewal, state_bound, ip);

	note("bound to %s -- renewal in %d seconds.",
	    piaddr(ip->client->active->address),
	    ip->client->active->renewal - cur_time);
	ip->client->state = S_BOUND;
	reinitialize_interfaces();
	go_daemon();
}

/*
 * state_bound is called when we've successfully bound to a particular
 * lease, but the renewal time on that lease has expired.   We are
 * expected to unicast a DHCPREQUEST to the server that gave us our
 * original lease.
 */
void
state_bound(void *ipp)
{
	struct interface_info *ip = ipp;

	ASSERT_STATE(state, S_BOUND);

	/* T1 has expired. */
	make_request(ip, ip->client->active);
	ip->client->xid = ip->client->packet.xid;

	if (ip->client->active->options[DHO_DHCP_SERVER_IDENTIFIER].len == 4) {
		memcpy(ip->client->destination.iabuf, ip->client->active->
		    options[DHO_DHCP_SERVER_IDENTIFIER].data, 4);
		ip->client->destination.len = 4;
	} else
		ip->client->destination = iaddr_broadcast;

	ip->client->first_sending = cur_time;
	ip->client->interval = ip->client->config->initial_interval;
	ip->client->state = S_RENEWING;

	/* Send the first packet immediately. */
	send_request(ip);
}

int
commit_leases(void)
{
	return (0);
}

int
write_lease(struct lease *lease)
{
	return (0);
}

void
db_startup(void)
{
}

void
bootp(struct packet *packet)
{
	struct iaddrlist *ap;

	if (packet->raw->op != BOOTREPLY)
		return;

	/* If there's a reject list, make sure this packet's sender isn't
	   on it. */
	for (ap = packet->interface->client->config->reject_list;
	     ap; ap = ap->next) {
		if (addr_eq(packet->client_addr, ap->addr)) {
			note("BOOTREPLY from %s rejected.", piaddr(ap->addr));
			return;
		}
	}
	dhcpoffer(packet);
}

void
dhcp(struct packet *packet)
{
	struct iaddrlist *ap;
	void (*handler)(struct packet *);
	char *type;

	switch (packet->packet_type) {
	case DHCPOFFER:
		handler = dhcpoffer;
		type = "DHCPOFFER";
		break;
	case DHCPNAK:
		handler = dhcpnak;
		type = "DHCPNACK";
		break;
	case DHCPACK:
		handler = dhcpack;
		type = "DHCPACK";
		break;
	default:
		return;
	}

	/* If there's a reject list, make sure this packet's sender isn't
	   on it. */
	for (ap = packet->interface->client->config->reject_list;
	     ap; ap = ap->next) {
		if (addr_eq(packet->client_addr, ap->addr)) {
			note("%s from %s rejected.", type, piaddr(ap->addr));
			return;
		}
	}
	(*handler)(packet);
}

void
dhcpoffer(struct packet *packet)
{
	struct interface_info *ip = packet->interface;
	struct client_lease *lease, *lp;
	int i;
	int arp_timeout_needed, stop_selecting;
	char *name = packet->options[DHO_DHCP_MESSAGE_TYPE].len ?
	    "DHCPOFFER" : "BOOTREPLY";

#ifdef DEBUG_PACKET
	dump_packet(packet);
#endif

	/* If we're not receptive to an offer right now, or if the offer
	   has an unrecognizable transaction id, then just drop it. */
	if (ip->client->state != S_SELECTING ||
	    packet->interface->client->xid != packet->raw->xid ||
	    (packet->interface->hw_address.hlen != packet->raw->hlen) ||
	    (memcmp(packet->interface->hw_address.haddr,
	    packet->raw->chaddr, packet->raw->hlen))) {
#ifdef DEBUG
		debug("%s in wrong transaction.", name);
#endif
		return;
	}

	note("%s from %s", name, piaddr(packet->client_addr));


	/* If this lease doesn't supply the minimum required parameters,
	   blow it off. */
	for (i = 0; ip->client->config->required_options[i]; i++) {
		if (!packet->options[ip->client->config->
		    required_options[i]].len) {
			note("%s isn't satisfactory.", name);
			return;
		}
	}

	/* If we've already seen this lease, don't record it again. */
	for (lease = ip->client->offered_leases;
	     lease; lease = lease->next) {
		if (lease->address.len == sizeof(packet->raw->yiaddr) &&
		    !memcmp(lease->address.iabuf,
		    &packet->raw->yiaddr, lease->address.len)) {
			debug("%s already seen.", name);
			return;
		}
	}

	lease = packet_to_lease(packet);
	if (!lease) {
		note("packet_to_lease failed.");
		return;
	}

	/* If this lease was acquired through a BOOTREPLY, record that
	   fact. */
	if (!packet->options[DHO_DHCP_MESSAGE_TYPE].len)
		lease->is_bootp = 1;

	/* Record the medium under which this lease was offered. */
	lease->medium = ip->client->medium;

	/* Send out an ARP Request for the offered IP address. */
	script_init(ip, "ARPSEND", lease->medium);
	script_write_params(ip, "check_", lease);
	/* If the script can't send an ARP request without waiting,
	   we'll be waiting when we do the ARPCHECK, so don't wait now. */
	if (script_go(ip))
		arp_timeout_needed = 0;
	else
		arp_timeout_needed = 2;

	/* Figure out when we're supposed to stop selecting. */
	stop_selecting =
	    ip->client->first_sending + ip->client->config->select_interval;

	/* If this is the lease we asked for, put it at the head of the
	   list, and don't mess with the arp request timeout. */
	if (lease->address.len == ip->client->requested_address.len &&
	    !memcmp(lease->address.iabuf,
	    ip->client->requested_address.iabuf,
	    ip->client->requested_address.len)) {
		lease->next = ip->client->offered_leases;
		ip->client->offered_leases = lease;
	} else {
		/* If we already have an offer, and arping for this
		   offer would take us past the selection timeout,
		   then don't extend the timeout - just hope for the
		   best. */
		if (ip->client->offered_leases &&
		    (cur_time + arp_timeout_needed) > stop_selecting)
			arp_timeout_needed = 0;

		/* Put the lease at the end of the list. */
		lease->next = NULL;
		if (!ip->client->offered_leases)
			ip->client->offered_leases = lease;
		else {
			for (lp = ip->client->offered_leases; lp->next;
			    lp = lp->next)
				;	/* nothing */
			lp->next = lease;
		}
	}

	/* If we're supposed to stop selecting before we've had time
	   to wait for the ARPREPLY, add some delay to wait for
	   the ARPREPLY. */
	if (stop_selecting - cur_time < arp_timeout_needed)
		stop_selecting = cur_time + arp_timeout_needed;

	/* If the selecting interval has expired, go immediately to
	   state_selecting().  Otherwise, time out into
	   state_selecting at the select interval. */
	if (stop_selecting <= 0)
		state_selecting(ip);
	else {
		add_timeout(stop_selecting, state_selecting, ip);
		cancel_timeout(send_discover, ip);
	}
}

/* Allocate a client_lease structure and initialize it from the parameters
   in the specified packet. */

struct client_lease *
packet_to_lease(struct packet *packet)
{
	struct client_lease *lease;
	int i;

	lease = malloc(sizeof(struct client_lease));

	if (!lease) {
		warn("dhcpoffer: no memory to record lease.");
		return (NULL);
	}

	memset(lease, 0, sizeof(*lease));

	/* Copy the lease options. */
	for (i = 0; i < 256; i++) {
		if (packet->options[i].len) {
			lease->options[i].data =
			    malloc(packet->options[i].len + 1);
			if (!lease->options[i].data) {
				warn("dhcpoffer: no memory for option %d", i);
				free_client_lease(lease);
				return (NULL);
			} else {
				memcpy(lease->options[i].data,
				    packet->options[i].data,
				    packet->options[i].len);
				lease->options[i].len =
				    packet->options[i].len;
				lease->options[i].data[lease->options[i].len] =
				    0;
			}
			if (!check_option(lease,i)) {
			        /* ignore a bogus lease offer */
				warn("Invalid lease option - ignoring offer");
				free_client_lease(lease);
				return (NULL);
			}
		}
	}

	lease->address.len = sizeof(packet->raw->yiaddr);
	memcpy(lease->address.iabuf, &packet->raw->yiaddr, lease->address.len);

	/* If the server name was filled out, copy it. */
	if ((!packet->options[DHO_DHCP_OPTION_OVERLOAD].len ||
	    !(packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)) &&
	    packet->raw->sname[0]) {
		lease->server_name = malloc(DHCP_SNAME_LEN + 1);
		if (!lease->server_name) {
			warn("dhcpoffer: no memory for server name.");
			free_client_lease(lease);
			return (NULL);
		}
		memcpy(lease->server_name, packet->raw->sname, DHCP_SNAME_LEN);
		lease->server_name[DHCP_SNAME_LEN]='\0';
		if (!res_hnok(lease->server_name) ) {
			warn("Bogus server name %s",  lease->server_name );
			free_client_lease(lease);
			return (NULL);
		}

	}

	/* Ditto for the filename. */
	if ((!packet->options[DHO_DHCP_OPTION_OVERLOAD].len ||
	    !(packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)) &&
	    packet->raw->file[0]) {
		        /* Don't count on the NUL terminator. */
		lease->filename = malloc(DHCP_FILE_LEN + 1);
		if (!lease->filename) {
			warn("dhcpoffer: no memory for filename.");
			free_client_lease(lease);
			return (NULL);
		}
		memcpy(lease->filename, packet->raw->file, DHCP_FILE_LEN);
		lease->filename[DHCP_FILE_LEN]='\0';
	}
	return lease;
}

void
dhcpnak(struct packet *packet)
{
	struct interface_info *ip = packet->interface;

	/* If we're not receptive to an offer right now, or if the offer
	   has an unrecognizable transaction id, then just drop it. */
	if (packet->interface->client->xid != packet->raw->xid ||
	    (packet->interface->hw_address.hlen != packet->raw->hlen) ||
	    (memcmp(packet->interface->hw_address.haddr,
	    packet->raw->chaddr, packet->raw->hlen))) {
#ifdef DEBUG
		debug("DHCPNAK in wrong transaction.");
#endif
		return;
	}

	if (ip->client->state != S_REBOOTING &&
	    ip->client->state != S_REQUESTING &&
	    ip->client->state != S_RENEWING &&
	    ip->client->state != S_REBINDING) {
#ifdef DEBUG
		debug("DHCPNAK in wrong state.");
#endif
		return;
	}

	note("DHCPNAK from %s", piaddr(packet->client_addr));

	if (!ip->client->active) {
		note("DHCPNAK with no active lease.\n");
		return;
	}

	free_client_lease(ip->client->active);
	ip->client->active = NULL;

	/* Stop sending DHCPREQUEST packets... */
	cancel_timeout(send_request, ip);

	ip->client->state = S_INIT;
	state_init(ip);
}

/* Send out a DHCPDISCOVER packet, and set a timeout to send out another
   one after the right interval has expired.  If we don't get an offer by
   the time we reach the panic interval, call the panic function. */

void
send_discover(void *ipp)
{
	struct interface_info *ip = ipp;

	int result;
	int interval;
	int increase = 1;

	/* Figure out how long it's been since we started transmitting. */
	interval = cur_time - ip->client->first_sending;

	/* If we're past the panic timeout, call the script and tell it
	   we haven't found anything for this interface yet. */
	if (interval > ip->client->config->timeout) {
		state_panic(ip);
		return;
	}

	/* If we're selecting media, try the whole list before doing
	   the exponential backoff, but if we've already received an
	   offer, stop looping, because we obviously have it right. */
	if (!ip->client->offered_leases &&
	    ip->client->config->media) {
		int fail = 0;
again:
		if (ip->client->medium) {
			ip->client->medium = ip->client->medium->next;
			increase = 0;
		}
		if (!ip->client->medium) {
			if (fail)
				error("No valid media types for %s!", ip->name);
			ip->client->medium = ip->client->config->media;
			increase = 1;
		}

		note("Trying medium \"%s\" %d", ip->client->medium->string,
		    increase);
		script_init(ip, "MEDIUM", ip->client->medium);
		if (script_go(ip))
			goto again;
	}

	/*
	 * If we're supposed to increase the interval, do so.  If it's
	 * currently zero (i.e., we haven't sent any packets yet), set
	 * it to one; otherwise, add to it a random number between zero
	 * and two times itself.  On average, this means that it will
	 * double with every transmission.
	 */
	if (increase) {
		if (!ip->client->interval)
			ip->client->interval =
			    ip->client->config->initial_interval;
		else {
			ip->client->interval += (random() >> 2) %
			    (2 * ip->client->interval);
		}

		/* Don't backoff past cutoff. */
		if (ip->client->interval >
		    ip->client->config->backoff_cutoff)
			ip->client->interval =
				((ip->client->config->backoff_cutoff / 2)
				 + ((random () >> 2) %
				    ip->client->config->backoff_cutoff));
	} else if (!ip->client->interval)
		ip->client->interval =
			ip->client->config->initial_interval;

	/* If the backoff would take us to the panic timeout, just use that
	   as the interval. */
	if (cur_time + ip->client->interval >
	    ip->client->first_sending + ip->client->config->timeout)
		ip->client->interval =
			(ip->client->first_sending +
			 ip->client->config->timeout) - cur_time + 1;

	/* Record the number of seconds since we started sending. */
	if (interval < 65536)
		ip->client->packet.secs = htons(interval);
	else
		ip->client->packet.secs = htons(65535);
	ip->client->secs = ip->client->packet.secs;

	note("DHCPDISCOVER on %s to %s port %d interval %d",
	    ip->name, inet_ntoa(sockaddr_broadcast.sin_addr),
	    ntohs(sockaddr_broadcast.sin_port), ip->client->interval);

	/* Send out a packet. */
	result = send_packet(ip, NULL, &ip->client->packet,
	    ip->client->packet_length, inaddr_any, &sockaddr_broadcast, NULL);

	add_timeout(cur_time + ip->client->interval, send_discover, ip);
}

/*
 * state_panic gets called if we haven't received any offers in a preset
 * amount of time.   When this happens, we try to use existing leases
 * that haven't yet expired, and failing that, we call the client script
 * and hope it can do something.
 */
void
state_panic(void *ipp)
{
	struct interface_info *ip = ipp;

	struct client_lease *loop = ip->client->active;
	struct client_lease *lp;

	note("No DHCPOFFERS received.");

	/* We may not have an active lease, but we may have some
	   predefined leases that we can try. */
	if (!ip->client->active && ip->client->leases)
		goto activate_next;

	/* Run through the list of leases and see if one can be used. */
	while (ip->client->active) {
		if (ip->client->active->expiry > cur_time) {
			note("Trying recorded lease %s",
			    piaddr(ip->client->active->address));
			/* Run the client script with the existing
			   parameters. */
			script_init(ip, "TIMEOUT",
			    ip->client->active->medium);
			script_write_params(ip, "new_", ip->client->active);
			if (ip->client->alias)
				script_write_params(ip, "alias_",
				    ip->client->alias);

			/* If the old lease is still good and doesn't
			   yet need renewal, go into BOUND state and
			   timeout at the renewal time. */
			if (!script_go(ip)) {
				if (cur_time <
				    ip->client->active->renewal) {
					ip->client->state = S_BOUND;
					note("bound: renewal in %d seconds.",
					    ip->client->active->renewal -
					    cur_time);
					add_timeout(
					    ip->client->active->renewal,
					    state_bound, ip);
				} else {
					ip->client->state = S_BOUND;
					note("bound: immediate renewal.");
					state_bound(ip);
				}
				reinitialize_interfaces();
				go_daemon();
				return;
			}
		}

		/* If there are no other leases, give up. */
		if (!ip->client->leases) {
			ip->client->leases = ip->client->active;
			ip->client->active = NULL;
			break;
		}

activate_next:
		/* Otherwise, put the active lease at the end of the
		   lease list, and try another lease.. */
		for (lp = ip->client->leases; lp->next; lp = lp->next)
			;
		lp->next = ip->client->active;
		if (lp->next)
			lp->next->next = NULL;
		ip->client->active = ip->client->leases;
		ip->client->leases = ip->client->leases->next;

		/* If we already tried this lease, we've exhausted the
		   set of leases, so we might as well give up for
		   now. */
		if (ip->client->active == loop)
			break;
		else if (!loop)
			loop = ip->client->active;
	}

	/* No leases were available, or what was available didn't work, so
	   tell the shell script that we failed to allocate an address,
	   and try again later. */
	if (onetry)
		exit(1);
	note("No working leases in persistent database - sleeping.\n");
	script_init(ip, "FAIL", NULL);
	if (ip->client->alias)
		script_write_params(ip, "alias_", ip->client->alias);
	script_go(ip);
	ip->client->state = S_INIT;
	add_timeout(cur_time + ip->client->config->retry_interval, state_init,
	    ip);
	go_daemon();
}

void
send_request(void *ipp)
{
	struct interface_info *ip = ipp;

	int result;
	int interval;
	struct sockaddr_in destination;
	struct in_addr from;

	/* Figure out how long it's been since we started transmitting. */
	interval = cur_time - ip->client->first_sending;

	/* If we're in the INIT-REBOOT or REQUESTING state and we're
	   past the reboot timeout, go to INIT and see if we can
	   DISCOVER an address... */
	/* XXX In the INIT-REBOOT state, if we don't get an ACK, it
	   means either that we're on a network with no DHCP server,
	   or that our server is down.  In the latter case, assuming
	   that there is a backup DHCP server, DHCPDISCOVER will get
	   us a new address, but we could also have successfully
	   reused our old address.  In the former case, we're hosed
	   anyway.  This is not a win-prone situation. */
	if ((ip->client->state == S_REBOOTING ||
	    ip->client->state == S_REQUESTING) &&
	    interval > ip->client->config->reboot_timeout) {
cancel:
		ip->client->state = S_INIT;
		cancel_timeout(send_request, ip);
		state_init(ip);
		return;
	}

	/* If we're in the reboot state, make sure the media is set up
	   correctly. */
	if (ip->client->state == S_REBOOTING &&
	    !ip->client->medium &&
	    ip->client->active->medium ) {
		script_init(ip, "MEDIUM", ip->client->active->medium);

		/* If the medium we chose won't fly, go to INIT state. */
		if (script_go(ip))
			goto cancel;

		/* Record the medium. */
		ip->client->medium = ip->client->active->medium;
	}

	/* If the lease has expired, relinquish the address and go back
	   to the INIT state. */
	if (ip->client->state != S_REQUESTING &&
	    cur_time > ip->client->active->expiry) {
		/* Run the client script with the new parameters. */
		script_init(ip, "EXPIRE", NULL);
		script_write_params(ip, "old_", ip->client->active);
		if (ip->client->alias)
			script_write_params(ip, "alias_", ip->client->alias);
		script_go(ip);

		/* Now do a preinit on the interface so that we can
		   discover a new address. */
		script_init(ip, "PREINIT", NULL);
		if (ip->client->alias)
			script_write_params(ip, "alias_", ip->client->alias);
		script_go(ip);

		ip->client->state = S_INIT;
		state_init(ip);
		return;
	}

	/* Do the exponential backoff... */
	if (!ip->client->interval)
		ip->client->interval = ip->client->config->initial_interval;
	else
		ip->client->interval += ((random () >> 2) %
		    (2 * ip->client->interval));

	/* Don't backoff past cutoff. */
	if (ip->client->interval >
	    ip->client->config->backoff_cutoff)
		ip->client->interval =
		    ((ip->client->config->backoff_cutoff / 2) +
		    ((random () >> 2) % ip->client->interval));

	/* If the backoff would take us to the expiry time, just set the
	   timeout to the expiry time. */
	if (ip->client->state != S_REQUESTING &&
	    cur_time + ip->client->interval >
	    ip->client->active->expiry)
		ip->client->interval =
		    ip->client->active->expiry - cur_time + 1;

	/* If the lease T2 time has elapsed, or if we're not yet bound,
	   broadcast the DHCPREQUEST rather than unicasting. */
	memset(&destination, 0, sizeof(destination));
	if (ip->client->state == S_REQUESTING ||
	    ip->client->state == S_REBOOTING ||
	    cur_time > ip->client->active->rebind)
		destination.sin_addr.s_addr = INADDR_BROADCAST;
	else
		memcpy(&destination.sin_addr.s_addr,
		    ip->client->destination.iabuf,
		    sizeof(destination.sin_addr.s_addr));
	destination.sin_port = remote_port;
	destination.sin_family = AF_INET;
	destination.sin_len = sizeof(destination);

	if (ip->client->state != S_REQUESTING)
		memcpy(&from, ip->client->active->address.iabuf,
		    sizeof(from));
	else
		from.s_addr = INADDR_ANY;

	/* Record the number of seconds since we started sending. */
	if (ip->client->state == S_REQUESTING)
		ip->client->packet.secs = ip->client->secs;
	else {
		if (interval < 65536)
			ip->client->packet.secs = htons(interval);
		else
			ip->client->packet.secs = htons(65535);
	}

	note("DHCPREQUEST on %s to %s port %d", ip->name,
	    inet_ntoa(destination.sin_addr), ntohs(destination.sin_port));

	if (destination.sin_addr.s_addr != INADDR_BROADCAST &&
	    fallback_interface)
		result = send_packet(fallback_interface, NULL,
		    &ip->client->packet, ip->client->packet_length, from,
		    &destination, NULL);
	else
		/* Send out a packet. */
		result = send_packet(ip, NULL, &ip->client->packet,
		    ip->client->packet_length, from, &destination, NULL);

	add_timeout(cur_time + ip->client->interval, send_request, ip);
}

void
send_decline(void *ipp)
{
	struct interface_info *ip = ipp;
	int result;

	note("DHCPDECLINE on %s to %s port %d", ip->name,
	    inet_ntoa(sockaddr_broadcast.sin_addr),
	    ntohs(sockaddr_broadcast.sin_port));

	/* Send out a packet. */
	result = send_packet(ip, NULL, &ip->client->packet,
	    ip->client->packet_length, inaddr_any, &sockaddr_broadcast, NULL);
}

void
send_release(void *ipp)
{
	struct interface_info *ip = ipp;

	int result;

	note("DHCPRELEASE on %s to %s port %d", ip->name,
	    inet_ntoa(sockaddr_broadcast.sin_addr),
	    ntohs(sockaddr_broadcast.sin_port));

	/* Send out a packet. */
	result = send_packet(ip, NULL, &ip->client->packet,
	    ip->client->packet_length, inaddr_any, &sockaddr_broadcast, NULL);
}

void
make_discover(struct interface_info *ip, struct client_lease *lease)
{
	unsigned char discover = DHCPDISCOVER;
	int i;

	struct tree_cache *options[256];
	struct tree_cache option_elements[256];

	memset(option_elements, 0, sizeof(option_elements));
	memset(options, 0, sizeof(options));
	memset(&ip->client->packet, 0, sizeof(ip->client->packet));

	/* Set DHCP_MESSAGE_TYPE to DHCPDISCOVER */
	i = DHO_DHCP_MESSAGE_TYPE;
	options[i] = &option_elements[i];
	options[i]->value = &discover;
	options[i]->len = sizeof(discover);
	options[i]->buf_size = sizeof(discover);
	options[i]->timeout = 0xFFFFFFFF;
	options[i]->tree = NULL;

	/* Request the options we want */
	i  = DHO_DHCP_PARAMETER_REQUEST_LIST;
	options[i] = &option_elements[i];
	options[i]->value = ip->client->config->requested_options;
	options[i]->len = ip->client->config->requested_option_count;
	options[i]->buf_size =
		ip->client->config->requested_option_count;
	options[i]->timeout = 0xFFFFFFFF;
	options[i]->tree = NULL;

	/* If we had an address, try to get it again. */
	if (lease) {
		ip->client->requested_address = lease->address;
		i = DHO_DHCP_REQUESTED_ADDRESS;
		options[i] = &option_elements[i];
		options[i]->value = lease->address.iabuf;
		options[i]->len = lease->address.len;
		options[i]->buf_size = lease->address.len;
		options[i]->timeout = 0xFFFFFFFF;
		options[i]->tree = NULL;
	} else
		ip->client->requested_address.len = 0;

	/* Send any options requested in the config file. */
	for (i = 0; i < 256; i++)
		if (!options[i] &&
		    ip->client->config->send_options[i].data) {
			options[i] = &option_elements[i];
			options[i]->value =
			    ip->client->config->send_options[i].data;
			options[i]->len =
			    ip->client->config->send_options[i].len;
			options[i]->buf_size =
			    ip->client->config->send_options[i].len;
			options[i]->timeout = 0xFFFFFFFF;
			options[i]->tree = NULL;
		}

	/* Set up the option buffer... */
	ip->client->packet_length = cons_options(NULL, &ip->client->packet, 0,
	    options, 0, 0, 0, NULL, 0);
	if (ip->client->packet_length < BOOTP_MIN_LEN)
		ip->client->packet_length = BOOTP_MIN_LEN;

	ip->client->packet.op = BOOTREQUEST;
	ip->client->packet.htype = ip->hw_address.htype;
	ip->client->packet.hlen = ip->hw_address.hlen;
	ip->client->packet.hops = 0;
	ip->client->packet.xid = arc4random();
	ip->client->packet.secs = 0; /* filled in by send_discover. */

	if (can_receive_unicast_unconfigured(ip))
		ip->client->packet.flags = 0;
	else
		ip->client->packet.flags = htons(BOOTP_BROADCAST);

	memset(&(ip->client->packet.ciaddr),
	    0, sizeof(ip->client->packet.ciaddr));
	memset(&(ip->client->packet.yiaddr),
	    0, sizeof(ip->client->packet.yiaddr));
	memset(&(ip->client->packet.siaddr),
	    0, sizeof(ip->client->packet.siaddr));
	memset(&(ip->client->packet.giaddr),
	    0, sizeof(ip->client->packet.giaddr));
	memcpy(ip->client->packet.chaddr,
	    ip->hw_address.haddr, ip->hw_address.hlen);

#ifdef DEBUG_PACKET
	dump_packet(sendpkt);
	dump_raw((unsigned char *)ip->client->packet, sendpkt->packet_length);
#endif
}


void
make_request(struct interface_info *ip, struct client_lease * lease)
{
	unsigned char request = DHCPREQUEST;
	int i;

	struct tree_cache *options[256];
	struct tree_cache option_elements[256];

	memset(options, 0, sizeof(options));
	memset(&ip->client->packet, 0, sizeof(ip->client->packet));

	/* Set DHCP_MESSAGE_TYPE to DHCPREQUEST */
	i = DHO_DHCP_MESSAGE_TYPE;
	options[i] = &option_elements[i];
	options[i]->value = &request;
	options[i]->len = sizeof(request);
	options[i]->buf_size = sizeof(request);
	options[i]->timeout = 0xFFFFFFFF;
	options[i]->tree = NULL;

	/* Request the options we want */
	i = DHO_DHCP_PARAMETER_REQUEST_LIST;
	options[i] = &option_elements[i];
	options[i]->value = ip->client->config->requested_options;
	options[i]->len = ip->client->config->requested_option_count;
	options[i]->buf_size =
		ip->client->config->requested_option_count;
	options[i]->timeout = 0xFFFFFFFF;
	options[i]->tree = NULL;

	/* If we are requesting an address that hasn't yet been assigned
	   to us, use the DHCP Requested Address option. */
	if (ip->client->state == S_REQUESTING) {
		/* Send back the server identifier... */
		i = DHO_DHCP_SERVER_IDENTIFIER;
		options[i] = &option_elements[i];
		options[i]->value = lease->options[i].data;
		options[i]->len = lease->options[i].len;
		options[i]->buf_size = lease->options[i].len;
		options[i]->timeout = 0xFFFFFFFF;
		options[i]->tree = NULL;
	}
	if (ip->client->state == S_REQUESTING ||
	    ip->client->state == S_REBOOTING) {
		ip->client->requested_address = lease->address;
		i = DHO_DHCP_REQUESTED_ADDRESS;
		options[i] = &option_elements[i];
		options[i]->value = lease->address.iabuf;
		options[i]->len = lease->address.len;
		options[i]->buf_size = lease->address.len;
		options[i]->timeout = 0xFFFFFFFF;
		options[i]->tree = NULL;
	} else
		ip->client->requested_address.len = 0;

	/* Send any options requested in the config file. */
	for (i = 0; i < 256; i++)
		if (!options[i] &&
		    ip->client->config->send_options[i].data) {
			options[i] = &option_elements[i];
			options[i]->value =
			    ip->client->config->send_options[i].data;
			options[i]->len =
			    ip->client->config->send_options[i].len;
			options[i]->buf_size =
			    ip->client->config->send_options[i].len;
			options[i]->timeout = 0xFFFFFFFF;
			options[i]->tree = NULL;
		}

	/* Set up the option buffer... */
	ip->client->packet_length = cons_options(NULL, &ip->client->packet, 0,
	    options, 0, 0, 0, NULL, 0);
	if (ip->client->packet_length < BOOTP_MIN_LEN)
		ip->client->packet_length = BOOTP_MIN_LEN;

	ip->client->packet.op = BOOTREQUEST;
	ip->client->packet.htype = ip->hw_address.htype;
	ip->client->packet.hlen = ip->hw_address.hlen;
	ip->client->packet.hops = 0;
	ip->client->packet.xid = ip->client->xid;
	ip->client->packet.secs = 0; /* Filled in by send_request. */

	/* If we own the address we're requesting, put it in ciaddr;
	   otherwise set ciaddr to zero. */
	if (ip->client->state == S_BOUND ||
	    ip->client->state == S_RENEWING ||
	    ip->client->state == S_REBINDING) {
		memcpy(&ip->client->packet.ciaddr,
		    lease->address.iabuf, lease->address.len);
		ip->client->packet.flags = 0;
	} else {
		memset(&ip->client->packet.ciaddr, 0,
		    sizeof(ip->client->packet.ciaddr));
		if (can_receive_unicast_unconfigured(ip))
			ip->client->packet.flags = 0;
		else
			ip->client->packet.flags = htons(BOOTP_BROADCAST);
	}

	memset(&ip->client->packet.yiaddr, 0,
	    sizeof(ip->client->packet.yiaddr));
	memset(&ip->client->packet.siaddr, 0,
	    sizeof(ip->client->packet.siaddr));
	memset(&ip->client->packet.giaddr, 0,
	    sizeof(ip->client->packet.giaddr));
	memcpy(ip->client->packet.chaddr,
	    ip->hw_address.haddr, ip->hw_address.hlen);

#ifdef DEBUG_PACKET
	dump_packet(sendpkt);
	dump_raw((unsigned char *)ip->client->packet, sendpkt->packet_length);
#endif
}

void
make_decline(struct interface_info *ip, struct client_lease *lease)
{
	unsigned char decline = DHCPDECLINE;
	int i;

	struct tree_cache *options[256];
	struct tree_cache message_type_tree;
	struct tree_cache requested_address_tree;
	struct tree_cache server_id_tree;
	struct tree_cache client_id_tree;

	memset(options, 0, sizeof(options));
	memset(&ip->client->packet, 0, sizeof(ip->client->packet));

	/* Set DHCP_MESSAGE_TYPE to DHCPDECLINE */
	i = DHO_DHCP_MESSAGE_TYPE;
	options[i] = &message_type_tree;
	options[i]->value = &decline;
	options[i]->len = sizeof(decline);
	options[i]->buf_size = sizeof(decline);
	options[i]->timeout = 0xFFFFFFFF;
	options[i]->tree = NULL;

	/* Send back the server identifier... */
	i = DHO_DHCP_SERVER_IDENTIFIER;
	options[i] = &server_id_tree;
	options[i]->value = lease->options[i].data;
	options[i]->len = lease->options[i].len;
	options[i]->buf_size = lease->options[i].len;
	options[i]->timeout = 0xFFFFFFFF;
	options[i]->tree = NULL;

	/* Send back the address we're declining. */
	i = DHO_DHCP_REQUESTED_ADDRESS;
	options[i] = &requested_address_tree;
	options[i]->value = lease->address.iabuf;
	options[i]->len = lease->address.len;
	options[i]->buf_size = lease->address.len;
	options[i]->timeout = 0xFFFFFFFF;
	options[i]->tree = NULL;

	/* Send the uid if the user supplied one. */
	i = DHO_DHCP_CLIENT_IDENTIFIER;
	if (ip->client->config->send_options[i].len) {
		options[i] = &client_id_tree;
		options[i]->value = ip->client->config->send_options[i].data;
		options[i]->len = ip->client->config->send_options[i].len;
		options[i]->buf_size = ip->client->config->send_options[i].len;
		options[i]->timeout = 0xFFFFFFFF;
		options[i]->tree = NULL;
	}


	/* Set up the option buffer... */
	ip->client->packet_length = cons_options(NULL, &ip->client->packet, 0,
	    options, 0, 0, 0, NULL, 0);
	if (ip->client->packet_length < BOOTP_MIN_LEN)
		ip->client->packet_length = BOOTP_MIN_LEN;

	ip->client->packet.op = BOOTREQUEST;
	ip->client->packet.htype = ip->hw_address.htype;
	ip->client->packet.hlen = ip->hw_address.hlen;
	ip->client->packet.hops = 0;
	ip->client->packet.xid = ip->client->xid;
	ip->client->packet.secs = 0; /* Filled in by send_request. */
	ip->client->packet.flags = 0;

	/* ciaddr must always be zero. */
	memset(&ip->client->packet.ciaddr, 0,
	    sizeof(ip->client->packet.ciaddr));
	memset(&ip->client->packet.yiaddr, 0,
	    sizeof(ip->client->packet.yiaddr));
	memset(&ip->client->packet.siaddr, 0,
	    sizeof(ip->client->packet.siaddr));
	memset(&ip->client->packet.giaddr, 0,
	    sizeof(ip->client->packet.giaddr));
	memcpy(ip->client->packet.chaddr,
	    ip->hw_address.haddr, ip->hw_address.hlen);

#ifdef DEBUG_PACKET
	dump_packet(sendpkt);
	dump_raw((unsigned char *)ip->client->packet, sendpkt->packet_length);
#endif
}

void
make_release(struct interface_info *ip, struct client_lease *lease)
{
	unsigned char request = DHCPRELEASE;
	int i;

	struct tree_cache *options[256];
	struct tree_cache message_type_tree;
	struct tree_cache server_id_tree;

	memset(options, 0, sizeof(options));
	memset(&ip->client->packet, 0, sizeof(ip->client->packet));

	/* Set DHCP_MESSAGE_TYPE to DHCPRELEASE */
	i = DHO_DHCP_MESSAGE_TYPE;
	options[i] = &message_type_tree;
	options[i]->value = &request;
	options[i]->len = sizeof(request);
	options[i]->buf_size = sizeof(request);
	options[i]->timeout = 0xFFFFFFFF;
	options[i]->tree = NULL;

	/* Send back the server identifier... */
	i = DHO_DHCP_SERVER_IDENTIFIER;
	options[i] = &server_id_tree;
	options[i]->value = lease->options[i].data;
	options[i]->len = lease->options[i].len;
	options[i]->buf_size = lease->options[i].len;
	options[i]->timeout = 0xFFFFFFFF;
	options[i]->tree = NULL;

	/* Set up the option buffer... */
	ip->client->packet_length = cons_options(NULL, &ip->client->packet, 0,
	    options, 0, 0, 0, NULL, 0);
	if (ip->client->packet_length < BOOTP_MIN_LEN)
		ip->client->packet_length = BOOTP_MIN_LEN;

	ip->client->packet.op = BOOTREQUEST;
	ip->client->packet.htype = ip->hw_address.htype;
	ip->client->packet.hlen = ip->hw_address.hlen;
	ip->client->packet.hops = 0;
	ip->client->packet.xid = random();
	ip->client->packet.secs = 0;
	ip->client->packet.flags = 0;

	memset(&ip->client->packet.ciaddr, 0,
	    sizeof(ip->client->packet.ciaddr));
	memset(&ip->client->packet.yiaddr, 0,
	    sizeof(ip->client->packet.yiaddr));
	memset(&ip->client->packet.siaddr, 0,
	    sizeof(ip->client->packet.siaddr));
	memset(&ip->client->packet.giaddr, 0,
	    sizeof(ip->client->packet.giaddr));
	memcpy(ip->client->packet.chaddr,
	    ip->hw_address.haddr, ip->hw_address.hlen);

#ifdef DEBUG_PACKET
	dump_packet(sendpkt);
	dump_raw((unsigned char *)ip->client->packet,
	    ip->client->packet_length);
#endif
}

void
free_client_lease(struct client_lease *lease)
{
	int i;

	if (lease->server_name)
		free(lease->server_name);
	if (lease->filename)
		free(lease->filename);
	for (i = 0; i < 256; i++) {
		if (lease->options[i].len)
			free(lease->options[i].data);
	}
	free(lease);
}

FILE *leaseFile;

void
rewrite_client_leases(void)
{
	struct interface_info *ip;
	struct client_lease *lp;

	if (leaseFile)
		fclose(leaseFile);
	leaseFile = fopen(path_dhclient_db, "w");
	if (!leaseFile)
		error("can't create %s: %m", path_dhclient_db);

	/* Write out all the leases attached to configured interfaces that
	   we know about. */
	for (ip = interfaces; ip; ip = ip->next) {
		for (lp = ip->client->leases; lp; lp = lp->next)
			write_client_lease(ip, lp, 1);
		if (ip->client->active)
			write_client_lease(ip, ip->client->active, 1);
	}

	/* Write out any leases that are attached to interfaces that aren't
	   currently configured. */
	for (ip = dummy_interfaces; ip; ip = ip->next) {
		for (lp = ip->client->leases; lp; lp = lp->next)
			write_client_lease(ip, lp, 1);
		if (ip->client->active)
			write_client_lease(ip, ip->client->active, 1);
	}
	fflush(leaseFile);
}

void
write_client_lease(struct interface_info *ip, struct client_lease *lease,
    int rewrite)
{
	int i;
	struct tm *t;
	static int leases_written;

	if (!rewrite) {
		if (leases_written++ > 20) {
			rewrite_client_leases();
			leases_written = 0;
		}
	}

	/* If the lease came from the config file, we don't need to stash
	   a copy in the lease database. */
	if (lease->is_static)
		return;

	if (!leaseFile) {	/* XXX */
		leaseFile = fopen(path_dhclient_db, "w");
		if (!leaseFile)
			error("can't create %s: %m", path_dhclient_db);
	}

	fprintf(leaseFile, "lease {\n");
	if (lease->is_bootp)
		fprintf(leaseFile, "  bootp;\n");
	fprintf(leaseFile, "  interface \"%s\";\n", ip->name);
	fprintf(leaseFile, "  fixed-address %s;\n", piaddr(lease->address));
	if (lease->filename)
		fprintf(leaseFile, "  filename \"%s\";\n", lease->filename);
	if (lease->server_name)
		fprintf(leaseFile, "  server-name \"%s\";\n",
		    lease->server_name);
	if (lease->medium)
		fprintf(leaseFile, "  medium \"%s\";\n", lease->medium->string);
	for (i = 0; i < 256; i++)
		if (lease->options[i].len)
			fprintf(leaseFile, "  option %s %s;\n",
			    dhcp_options[i].name,
			    pretty_print_option(i, lease->options[i].data,
			    lease->options[i].len, 1, 1));

	/* Note: the following is not a Y2K bug - it's a Y1.9K bug.   Until
	   somebody invents a time machine, I think we can safely disregard
	   it. */
	t = gmtime(&lease->renewal);
	fprintf(leaseFile, "  renew %d %d/%d/%d %02d:%02d:%02d;\n",
	    t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
	    t->tm_hour, t->tm_min, t->tm_sec);
	t = gmtime(&lease->rebind);
	fprintf(leaseFile, "  rebind %d %d/%d/%d %02d:%02d:%02d;\n",
	    t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
	    t->tm_hour, t->tm_min, t->tm_sec);
	t = gmtime(&lease->expiry);
	fprintf(leaseFile, "  expire %d %d/%d/%d %02d:%02d:%02d;\n",
	    t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
	    t->tm_hour, t->tm_min, t->tm_sec);
	fprintf(leaseFile, "}\n");
	fflush(leaseFile);
}

/* Variables holding name of script and file pointer for writing to
   script.   Needless to say, this is not reentrant - only one script
   can be invoked at a time. */
char scriptName[256];
FILE *scriptFile;

void
script_init(struct interface_info *ip, char *reason, struct string_list *medium)
{
	if (ip) {
		ip->client->scriptEnvsize = 100;
		if (ip->client->scriptEnv == NULL)
			ip->client->scriptEnv =
			    malloc(ip->client->scriptEnvsize * sizeof(char *));
		if (ip->client->scriptEnv == NULL)
			error("script_init: no memory for environment");

		ip->client->scriptEnv[0]=strdup(CLIENT_PATH);
		if (ip->client->scriptEnv[0] == NULL)
			error("script_init: no memory for environment");

		ip->client->scriptEnv[1] = NULL;

		script_set_env(ip->client, "", "interface", ip->name);

		if (medium)
			script_set_env(ip->client, "", "medium",
			    medium->string);

		script_set_env(ip->client, "", "reason", reason);
	}
}

void
script_write_params(struct interface_info *ip, char *prefix,
    struct client_lease *lease)
{
	int i;
	u_int8_t dbuf[1500];
	int len = 0;
	char tbuf[128];

	script_set_env(ip->client, prefix, "ip_address",
	    piaddr(lease->address));

	/* For the benefit of Linux (and operating systems which may
	   have similar needs), compute the network address based on
	   the supplied ip address and netmask, if provided.  Also
	   compute the broadcast address (the host address all ones
	   broadcast address, not the host address all zeroes
	   broadcast address). */

	if (lease->options[DHO_SUBNET_MASK].len &&
	    (lease->options[DHO_SUBNET_MASK].len <
	    sizeof(lease->address.iabuf))) {
		struct iaddr netmask, subnet, broadcast;

		memcpy(netmask.iabuf,
		    lease->options[DHO_SUBNET_MASK].data,
		    lease->options[DHO_SUBNET_MASK].len);
		netmask.len = lease->options[DHO_SUBNET_MASK].len;

		subnet = subnet_number(lease->address, netmask);
		if (subnet.len) {
			script_set_env(ip->client, prefix, "network_number",
			    piaddr(subnet));
			if (!lease->options[DHO_BROADCAST_ADDRESS].len) {
				broadcast = broadcast_addr(subnet, netmask);
				if (broadcast.len)
					script_set_env(ip->client, prefix,
					    "broadcast_address",
					    piaddr(broadcast));
			}
		}
	}

	if (lease->filename)
		script_set_env(ip->client, prefix, "filename", lease->filename);
	if (lease->server_name)
		script_set_env(ip->client, prefix, "server_name",
		    lease->server_name);
	for (i = 0; i < 256; i++) {
		u_int8_t *dp = NULL;

		if (ip->client->config->defaults[i].len) {
			if (lease->options[i].len) {
				switch (
				    ip->client->config->default_actions[i]) {
				case ACTION_DEFAULT:
					dp = lease->options[i].data;
					len = lease->options[i].len;
					break;
				case ACTION_SUPERSEDE:
supersede:
					dp = ip->client->
						config->defaults[i].data;
					len = ip->client->
						config->defaults[i].len;
					break;
				case ACTION_PREPEND:
					len = ip->client->
					    config->defaults[i].len +
					    lease->options[i].len;
					if (len > sizeof(dbuf)) {
						warn("no space to %s %s",
						    "prepend option",
						    dhcp_options[i].name);
						goto supersede;
					}
					dp = dbuf;
					memcpy(dp,
						ip->client->
						config->defaults[i].data,
						ip->client->
						config->defaults[i].len);
					memcpy(dp + ip->client->
						config->defaults[i].len,
						lease->options[i].data,
						lease->options[i].len);
					dp[len] = '\0';
					break;
				case ACTION_APPEND:
					len = ip->client->
					    config->defaults[i].len +
					    lease->options[i].len;
					if (len > sizeof(dbuf)) {
						warn("no space to %s %s",
						    "append option",
						    dhcp_options[i].name);
						goto supersede;
					}
					dp = dbuf;
					memcpy(dp,
						lease->options[i].data,
						lease->options[i].len);
					memcpy(dp + lease->options[i].len,
						ip->client->
						config->defaults[i].data,
						ip->client->
						config->defaults[i].len);
					dp[len] = '\0';
				}
			} else {
				dp = ip->client->
					config->defaults[i].data;
				len = ip->client->
					config->defaults[i].len;
			}
		} else if (lease->options[i].len) {
			len = lease->options[i].len;
			dp = lease->options[i].data;
		} else {
			len = 0;
		}
		if (len) {
			char name[256];
			if (dhcp_option_ev_name(name, sizeof(name),
						 &dhcp_options[i]))
				script_set_env(ip->client, prefix, name,
				    pretty_print_option(i, dp, len, 0, 0));
		}
	}
	snprintf(tbuf, sizeof(tbuf), "%d", (int)lease->expiry);
	script_set_env(ip->client, prefix, "expiry", tbuf);
}

int
script_go(struct interface_info *ip)
{
	char *scriptName;
	char *argv[2];
	char **envp;
	char *epp[3];
	char reason[] = "REASON=NBI";
	static char client_path[] = CLIENT_PATH;
	int pid, wpid, wstatus;

	if (ip) {
		scriptName = ip->client->config->script_name;
		envp = ip->client->scriptEnv;
	} else {
		scriptName = top_level_config.script_name;
		epp[0] = reason;
		epp[1] = client_path;
		epp[2] = NULL;
		envp = epp;
	}

	argv[0] = scriptName;
	argv[1] = NULL;

	pid = fork();
	if (pid < 0) {
		error("fork: %m");
		wstatus = 0;
	} else if (pid) {
		do {
			wpid = wait(&wstatus);
		} while (wpid != pid && wpid > 0);
		if (wpid < 0) {
			error("wait: %m");
			wstatus = 0;
		}
	} else {
		execve(scriptName, argv, envp);
		error("execve (%s, ...): %m", scriptName);
		exit(0);
	}

	if (ip)
		script_flush_env(ip->client);

	return (wstatus & 0xff);
}

void
script_set_env(struct client_state *client, const char *prefix,
    const char *name, const char *value)
{
	int i, namelen;

	namelen = strlen(name);

	for (i = 0; client->scriptEnv[i]; i++)
		if (strncmp(client->scriptEnv[i], name, namelen) == 0 &&
		    client->scriptEnv[i][namelen] == '=')
			break;

	if (client->scriptEnv[i])
		/* Reuse the slot. */
		free(client->scriptEnv[i]);
	else {
		/* New variable.  Expand if necessary. */
		if (i >= client->scriptEnvsize - 1) {
			char **newscriptEnv;
			int newscriptEnvsize = client->scriptEnvsize + 50;
			newscriptEnv = realloc(client->scriptEnv,
			    newscriptEnvsize);
			if (newscriptEnv == NULL) {
				free(client->scriptEnv);
				client->scriptEnv = NULL;
				client->scriptEnvsize = 0;
				error("script_set_env: no memory for variable");
			}
			client->scriptEnv = newscriptEnv;
			client->scriptEnvsize = newscriptEnvsize;
		}
		/* need to set the NULL pointer at end of array beyond
		   the new slot. */
		client->scriptEnv[i + 1] = NULL;
	}
	/* Allocate space and format the variable in the appropriate slot. */
	client->scriptEnv[i] = malloc(strlen(prefix) + strlen(name) + 1 +
	    strlen(value) + 1);
	if (client->scriptEnv[i] == NULL)
		error("script_set_env: no memory for variable assignment");

	snprintf(client->scriptEnv[i], strlen(prefix) + strlen(name) +
	    1 + strlen(value) + 1, "%s%s=%s", prefix, name, value);
}

void
script_flush_env(struct client_state *client)
{
	int i;

	for (i = 0; client->scriptEnv[i]; i++) {
		free(client->scriptEnv[i]);
		client->scriptEnv[i] = NULL;
	}
	client->scriptEnvsize = 0;
}

int
dhcp_option_ev_name(char *buf, size_t buflen, struct option *option)
{
	int i;

	for (i = 0; option->name[i]; i++) {
		if (i + 1 == buflen)
			return 0;
		if (option->name[i] == '-')
			buf[i] = '_';
		else
			buf[i] = option->name[i];
	}

	buf[i] = 0;
	return 1;
}

void
go_daemon(void)
{
	static int state = 0;
	int pid;

	/* Don't become a daemon if the user requested otherwise. */
	if (no_daemon) {
		write_client_pid_file();
		return;
	}

	/* Only do it once. */
	if (state)
		return;
	state = 1;

	/* Stop logging to stderr... */
	log_perror = 0;

	/* Become a daemon... */
	if ((pid = fork()) < 0)
		error("Can't fork daemon: %m");
	else if (pid)
		exit(0);
	/* Become session leader and get pid... */
	pid = setsid();

	/* Close standard I/O descriptors. */
	close(0);
	close(1);
	close(2);

	write_client_pid_file();
}

void
write_client_pid_file()
{
	FILE *pf;
	int pfdesc;

	pfdesc = open(path_dhclient_pid, O_CREAT | O_TRUNC | O_WRONLY, 0644);

	if (pfdesc < 0) {
		warn("Can't create %s: %m", path_dhclient_pid);
		return;
	}

	pf = fdopen(pfdesc, "w");
	if (!pf)
		warn("Can't fdopen %s: %m", path_dhclient_pid);
	else {
		fprintf(pf, "%ld\n", (long)getpid());
		fclose(pf);
	}
}

int
check_option(struct client_lease *l, int option)
{
	char *opbuf;
	char *sbuf;

	/* we use this, since this is what gets passed to dhclient-script */

	opbuf = pretty_print_option(option, l->options[option].data,
	    l->options[option].len, 0, 0);

	sbuf = option_as_string(option, l->options[option].data,
	    l->options[option].len);

	switch (option) {
	case DHO_SUBNET_MASK :
	case DHO_TIME_SERVERS :
	case DHO_NAME_SERVERS :
	case DHO_ROUTERS :
	case DHO_DOMAIN_NAME_SERVERS :
	case DHO_LOG_SERVERS :
	case DHO_COOKIE_SERVERS :
	case DHO_LPR_SERVERS :
	case DHO_IMPRESS_SERVERS :
	case DHO_RESOURCE_LOCATION_SERVERS :
	case DHO_SWAP_SERVER :
	case DHO_BROADCAST_ADDRESS :
	case DHO_NIS_SERVERS :
	case DHO_NTP_SERVERS :
	case DHO_NETBIOS_NAME_SERVERS :
	case DHO_NETBIOS_DD_SERVER :
	case DHO_FONT_SERVERS :
	case DHO_DHCP_SERVER_IDENTIFIER :
		/* These should be a list of one or more IP addresses,
		 * separated by spaces. If they aren't, this lease is not
		 * valid.
		 */
		if (!ipv4addrs(opbuf)) {
			warn("Invalid IP address in option: %s", opbuf);
			return (0);
		}
		return (1)  ;
	case DHO_HOST_NAME :
	case DHO_DOMAIN_NAME :
	case DHO_NIS_DOMAIN :
		/* This has to be a valid internet domain name */
		if (!res_hnok(sbuf)) {
			warn("Bogus Host Name option %d: %s (%s)", option,
			    sbuf, opbuf);
			return (0);
		}
		return (1);
	case DHO_PAD :
	case DHO_TIME_OFFSET :
	case DHO_BOOT_SIZE :
	case DHO_MERIT_DUMP :
	case DHO_ROOT_PATH :
	case DHO_EXTENSIONS_PATH :
	case DHO_IP_FORWARDING :
	case DHO_NON_LOCAL_SOURCE_ROUTING :
	case DHO_POLICY_FILTER :
	case DHO_MAX_DGRAM_REASSEMBLY :
	case DHO_DEFAULT_IP_TTL :
	case DHO_PATH_MTU_AGING_TIMEOUT :
	case DHO_PATH_MTU_PLATEAU_TABLE :
	case DHO_INTERFACE_MTU :
	case DHO_ALL_SUBNETS_LOCAL :
	case DHO_PERFORM_MASK_DISCOVERY :
	case DHO_MASK_SUPPLIER :
	case DHO_ROUTER_DISCOVERY :
	case DHO_ROUTER_SOLICITATION_ADDRESS :
	case DHO_STATIC_ROUTES :
	case DHO_TRAILER_ENCAPSULATION :
	case DHO_ARP_CACHE_TIMEOUT :
	case DHO_IEEE802_3_ENCAPSULATION :
	case DHO_DEFAULT_TCP_TTL :
	case DHO_TCP_KEEPALIVE_INTERVAL :
	case DHO_TCP_KEEPALIVE_GARBAGE :
	case DHO_VENDOR_ENCAPSULATED_OPTIONS :
	case DHO_NETBIOS_NODE_TYPE :
	case DHO_NETBIOS_SCOPE :
	case DHO_X_DISPLAY_MANAGER :
	case DHO_DHCP_REQUESTED_ADDRESS :
	case DHO_DHCP_LEASE_TIME :
	case DHO_DHCP_OPTION_OVERLOAD :
	case DHO_DHCP_MESSAGE_TYPE :
	case DHO_DHCP_PARAMETER_REQUEST_LIST :
	case DHO_DHCP_MESSAGE :
	case DHO_DHCP_MAX_MESSAGE_SIZE :
	case DHO_DHCP_RENEWAL_TIME :
	case DHO_DHCP_REBINDING_TIME :
	case DHO_DHCP_CLASS_IDENTIFIER :
	case DHO_DHCP_CLIENT_IDENTIFIER :
	case DHO_DHCP_USER_CLASS_ID :
	case DHO_END :
		/* do nothing */
		return (1);
	default:
		warn("unknown dhcp option value 0x%x", option);
		return (unknown_ok);
	}
}

int
res_hnok(const char *dn)
{
	int pch = PERIOD, ch = *dn++;

	while (ch != '\0') {
		int nch = *dn++;

		if (periodchar(ch)) {
			;
		} else if (periodchar(pch)) {
			if (!borderchar(ch))
				return (0);
		} else if (periodchar(nch) || nch == '\0') {
			if (!borderchar(ch))
				return (0);
		} else {
			if (!middlechar(ch))
				return (0);
		}
		pch = ch, ch = nch;
	}
	return (1);
}

/* Does buf consist only of dotted decimal ipv4 addrs?
 * return how many if so,
 * otherwise, return 0
 */
int
ipv4addrs(char * buf)
{
	struct in_addr jnk;
	int count = 0;

	while (inet_aton(buf, &jnk) == 1){
		count++;
		while (periodchar(*buf) || digitchar(*buf))
			buf++;
		if (*buf == '\0')
			return (count);
		while (*buf ==  ' ')
			buf++;
	}
	return (0);
}


/* Format the specified option as a string */

char *
option_as_string(unsigned int code, unsigned char *data, int len)
{
	static char optbuf[32768]; /* XXX */
	char *op = optbuf;
	int opleft = sizeof(optbuf);
	unsigned char *dp = data;

	/* Code should be between 0 and 255. */
	if (code > 255)
		error("option_as_string: bad code %d\n", code);

	for (; dp < data + len; dp++) {
		if (!isascii(*dp) ||
		    !isprint(*dp)) {
			if (dp + 1 != data + len ||
			    *dp != 0) {
				snprintf(op, opleft,
				    "\\%03o", *dp);
				op += 4;
				opleft -= 4;
			}
		} else if (*dp == '"' ||
		    *dp == '\'' ||
		    *dp == '$' ||
		    *dp == '`' ||
		    *dp == '\\') {
			*op++ = '\\';
			*op++ = *dp;
			opleft -= 2;
		} else {
			*op++ = *dp;
			opleft--;
		}
	}
	if (opleft < 1)
		goto toobig;
	*op = 0;
	return optbuf;
toobig:
	warn("dhcp option too large");
	return "<error>";
}