networking/udhcp/dhcpc.c - busybox - Git at Google

 /* dhcpc.c
  *
  * udhcp DHCP client
  *
  * Russ Dill <Russ.Dill@asu.edu> July 2001
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 #include <sys/time.h>
 #include <sys/file.h>
 #include <unistd.h>
 #include <getopt.h>
 #include <stdlib.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <signal.h>
 #include <time.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <net/if.h>
 #include <errno.h>

 #include "dhcpd.h"
 #include "dhcpc.h"
 #include "options.h"
 #include "clientpacket.h"
 #include "script.h"
 #include "socket.h"
 #include "common.h"

 static int state;
 static unsigned long requested_ip; /* = 0 */
 static unsigned long server_addr;
 static unsigned long timeout;
 static int packet_num; /* = 0 */
 static int fd = -1;

 #define LISTEN_NONE 0
 #define LISTEN_KERNEL 1
 #define LISTEN_RAW 2
 static int listen_mode;

 #ifdef CONFIG_INSTALL_NO_USR
 #define DEFAULT_SCRIPT	"/share/udhcpc/default.script"
 #else
 #define DEFAULT_SCRIPT	"/usr/share/udhcpc/default.script"
 #endif

 struct client_config_t client_config = {
 	/* Default options. */
 	abort_if_no_lease: 0,
 	foreground: 0,
 	quit_after_lease: 0,
 	background_if_no_lease: 0,
 	interface: "eth0",
 	pidfile: NULL,
 	script: DEFAULT_SCRIPT,
 	clientid: NULL,
 	hostname: NULL,
 	ifindex: 0,
 	arp: "\0\0\0\0\0\0",		/* appease gcc-3.0 */
 };

 /* just a little helper */
 static void change_mode(int new_mode)
 {
 	DEBUG(LOG_INFO, "entering %s listen mode",
 		new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
 	if (fd >= 0) close(fd);
 	fd = -1;
 	listen_mode = new_mode;
 }


 /* perform a renew */
 static void perform_renew(void)
 {
 	LOG(LOG_INFO, "Performing a DHCP renew");
 	switch (state) {
 	case BOUND:
 		change_mode(LISTEN_KERNEL);
 	case RENEWING:
 	case REBINDING:
 		state = RENEW_REQUESTED;
 		break;
 	case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
 		run_script(NULL, "deconfig");
 	case REQUESTING:
 	case RELEASED:
 		change_mode(LISTEN_RAW);
 		state = INIT_SELECTING;
 		break;
 	case INIT_SELECTING:
 		break;
 	}

 	/* start things over */
 	packet_num = 0;

 	/* Kill any timeouts because the user wants this to hurry along */
 	timeout = 0;
 }


 /* perform a release */
 static void perform_release(void)
 {
 	char buffer[16];
 	struct in_addr temp_addr;

 	/* send release packet */
 	if (state == BOUND || state == RENEWING || state == REBINDING) {
 		temp_addr.s_addr = server_addr;
 		sprintf(buffer, "%s", inet_ntoa(temp_addr));
 		temp_addr.s_addr = requested_ip;
 		LOG(LOG_INFO, "Unicasting a release of %s to %s",
 				inet_ntoa(temp_addr), buffer);
 		send_release(server_addr, requested_ip); /* unicast */
 		run_script(NULL, "deconfig");
 	}
 	LOG(LOG_INFO, "Entering released state");

 	change_mode(LISTEN_NONE);
 	state = RELEASED;
 	timeout = 0x7fffffff;
 }


 static void client_background(void)
 {
 	background(client_config.pidfile);
 	client_config.foreground = 1; /* Do not fork again. */
 	client_config.background_if_no_lease = 0;
 }


 int udhcpc_main(int argc, char *argv[])
 {
 	unsigned char *temp, *message;
 	unsigned long t1 = 0, t2 = 0, xid = 0;
 	unsigned long start = 0, lease;
 	fd_set rfds;
 	int retval;
 	struct timeval tv;
 	int c, len;
 	struct dhcpMessage packet;
 	struct in_addr temp_addr;
 	time_t now;
 	int max_fd;
 	int sig;

 	static const struct option arg_options[] = {
 		{"clientid",	required_argument,	0, 'c'},
 		{"foreground",	no_argument,		0, 'f'},
 		{"background",	no_argument,		0, 'b'},
 		{"hostname",	required_argument,	0, 'H'},
 		{"hostname",    required_argument,      0, 'h'},
 		{"interface",	required_argument,	0, 'i'},
 		{"now", 	no_argument,		0, 'n'},
 		{"pidfile",	required_argument,	0, 'p'},
 		{"quit",	no_argument,		0, 'q'},
 		{"request",	required_argument,	0, 'r'},
 		{"script",	required_argument,	0, 's'},
 		{"version",	no_argument,		0, 'v'},
 		{0, 0, 0, 0}
 	};

 	/* get options */
 	while (1) {
 		int option_index = 0;
 		c = getopt_long(argc, argv, "c:fbH:h:i:np:qr:s:v", arg_options, &option_index);
 		if (c == -1) break;

 		switch (c) {
 		case 'c':
 			len = strlen(optarg) > 255 ? 255 : strlen(optarg);
 			if (client_config.clientid) free(client_config.clientid);
 			client_config.clientid = xmalloc(len + 2);
 			client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
 			client_config.clientid[OPT_LEN] = len;
 			client_config.clientid[OPT_DATA] = '\0';
 			strncpy(client_config.clientid + OPT_DATA, optarg, len);
 			break;
 		case 'f':
 			client_config.foreground = 1;
 			break;
 		case 'b':
 			client_config.background_if_no_lease = 1;
 			break;
 		case 'h':
 		case 'H':
 			len = strlen(optarg) > 255 ? 255 : strlen(optarg);
 			if (client_config.hostname) free(client_config.hostname);
 			client_config.hostname = xmalloc(len + 2);
 			client_config.hostname[OPT_CODE] = DHCP_HOST_NAME;
 			client_config.hostname[OPT_LEN] = len;
 			strncpy(client_config.hostname + 2, optarg, len);
 			break;
 		case 'i':
 			client_config.interface =  optarg;
 			break;
 		case 'n':
 			client_config.abort_if_no_lease = 1;
 			break;
 		case 'p':
 			client_config.pidfile = optarg;
 			break;
 		case 'q':
 			client_config.quit_after_lease = 1;
 			break;
 		case 'r':
 			requested_ip = inet_addr(optarg);
 			break;
 		case 's':
 			client_config.script = optarg;
 			break;
 		case 'v':
 			bb_error_msg("version %s\n", VERSION);
 			return(0);
 			break;
 		default:
 			bb_show_usage();
 		}
 	}

 	start_log("client");
 	if (read_interface(client_config.interface, &client_config.ifindex,
 			   NULL, client_config.arp) < 0)
 		return(1);

 	if (!client_config.clientid) {
 		client_config.clientid = xmalloc(6 + 3);
 		client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
 		client_config.clientid[OPT_LEN] = 7;
 		client_config.clientid[OPT_DATA] = 1;
 		memcpy(client_config.clientid + 3, client_config.arp, 6);
 	}

 	/* setup signal handlers */
 	udhcp_set_signal_pipe(SIGUSR2);

 	state = INIT_SELECTING;
 	run_script(NULL, "deconfig");
 	change_mode(LISTEN_RAW);

 	for (;;) {

 		tv.tv_sec = timeout - time(0);
 		tv.tv_usec = 0;
 		FD_ZERO(&rfds);

 		if (listen_mode != LISTEN_NONE && fd < 0) {
 			if (listen_mode == LISTEN_KERNEL)
 				fd = listen_socket(INADDR_ANY, CLIENT_PORT, client_config.interface);
 			else
 				fd = raw_socket(client_config.ifindex);
 			if (fd < 0) {
 				LOG(LOG_ERR, "FATAL: couldn't listen on socket, %m");
 				return(0);
 			}
 		}
 		if (fd >= 0) FD_SET(fd, &rfds);
 		FD_SET(udhcp_signal_pipe[0], &rfds);

 		if (tv.tv_sec > 0) {
 			DEBUG(LOG_INFO, "Waiting on select...\n");
 			max_fd = udhcp_signal_pipe[0] > fd ? udhcp_signal_pipe[0] : fd;
 			retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
 		} else retval = 0; /* If we already timed out, fall through */

 		now = time(0);
 		if (retval == 0) {
 			/* timeout dropped to zero */
 			switch (state) {
 			case INIT_SELECTING:
 				if (packet_num < 3) {
 					if (packet_num == 0)
 						xid = random_xid();

 					/* send discover packet */
 					send_discover(xid, requested_ip); /* broadcast */

 					timeout = now + ((packet_num == 2) ? 4 : 2);
 					packet_num++;
 				} else {
 					if (client_config.background_if_no_lease) {
 						LOG(LOG_INFO, "No lease, forking to background.");
 						client_background();
 					} else if (client_config.abort_if_no_lease) {
 						LOG(LOG_INFO, "No lease, failing.");
 						return(1);
 				  	}
 					/* wait to try again */
 					packet_num = 0;
 					timeout = now + 60;
 				}
 				break;
 			case RENEW_REQUESTED:
 			case REQUESTING:
 				if (packet_num < 3) {
 					/* send request packet */
 					if (state == RENEW_REQUESTED)
 						send_renew(xid, server_addr, requested_ip); /* unicast */
 					else send_selecting(xid, server_addr, requested_ip); /* broadcast */

 					timeout = now + ((packet_num == 2) ? 10 : 2);
 					packet_num++;
 				} else {
 					/* timed out, go back to init state */
 					if (state == RENEW_REQUESTED) run_script(NULL, "deconfig");
 					state = INIT_SELECTING;
 					timeout = now;
 					packet_num = 0;
 					change_mode(LISTEN_RAW);
 				}
 				break;
 			case BOUND:
 				/* Lease is starting to run out, time to enter renewing state */
 				state = RENEWING;
 				change_mode(LISTEN_KERNEL);
 				DEBUG(LOG_INFO, "Entering renew state");
 				/* fall right through */
 			case RENEWING:
 				/* Either set a new T1, or enter REBINDING state */
 				if ((t2 - t1) <= (lease / 14400 + 1)) {
 					/* timed out, enter rebinding state */
 					state = REBINDING;
 					timeout = now + (t2 - t1);
 					DEBUG(LOG_INFO, "Entering rebinding state");
 				} else {
 					/* send a request packet */
 					send_renew(xid, server_addr, requested_ip); /* unicast */

 					t1 = (t2 - t1) / 2 + t1;
 					timeout = t1 + start;
 				}
 				break;
 			case REBINDING:
 				/* Either set a new T2, or enter INIT state */
 				if ((lease - t2) <= (lease / 14400 + 1)) {
 					/* timed out, enter init state */
 					state = INIT_SELECTING;
 					LOG(LOG_INFO, "Lease lost, entering init state");
 					run_script(NULL, "deconfig");
 					timeout = now;
 					packet_num = 0;
 					change_mode(LISTEN_RAW);
 				} else {
 					/* send a request packet */
 					send_renew(xid, 0, requested_ip); /* broadcast */

 					t2 = (lease - t2) / 2 + t2;
 					timeout = t2 + start;
 				}
 				break;
 			case RELEASED:
 				/* yah, I know, *you* say it would never happen */
 				timeout = 0x7fffffff;
 				break;
 			}
 		} else if (retval > 0 && listen_mode != LISTEN_NONE && FD_ISSET(fd, &rfds)) {
 			/* a packet is ready, read it */

 			if (listen_mode == LISTEN_KERNEL)
 				len = get_packet(&packet, fd);
 			else len = get_raw_packet(&packet, fd);

 			if (len == -1 && errno != EINTR) {
 				DEBUG(LOG_INFO, "error on read, %m, reopening socket");
 				change_mode(listen_mode); /* just close and reopen */
 			}
 			if (len < 0) continue;

 			if (packet.xid != xid) {
 				DEBUG(LOG_INFO, "Ignoring XID %lx (our xid is %lx)",
 					(unsigned long) packet.xid, xid);
 				continue;
 			}

 			if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
 				DEBUG(LOG_ERR, "couldnt get option from packet -- ignoring");
 				continue;
 			}

 			switch (state) {
 			case INIT_SELECTING:
 				/* Must be a DHCPOFFER to one of our xid's */
 				if (*message == DHCPOFFER) {
 					if ((temp = get_option(&packet, DHCP_SERVER_ID))) {
 						memcpy(&server_addr, temp, 4);
 						xid = packet.xid;
 						requested_ip = packet.yiaddr;

 						/* enter requesting state */
 						state = REQUESTING;
 						timeout = now;
 						packet_num = 0;
 					} else {
 						DEBUG(LOG_ERR, "No server ID in message");
 					}
 				}
 				break;
 			case RENEW_REQUESTED:
 			case REQUESTING:
 			case RENEWING:
 			case REBINDING:
 				if (*message == DHCPACK) {
 					if (!(temp = get_option(&packet, DHCP_LEASE_TIME))) {
 						LOG(LOG_ERR, "No lease time with ACK, using 1 hour lease");
 						lease = 60 * 60;
 					} else {
 						memcpy(&lease, temp, 4);
 						lease = ntohl(lease);
 					}

 					/* enter bound state */
 					t1 = lease / 2;

 					/* little fixed point for n * .875 */
 					t2 = (lease * 0x7) >> 3;
 					temp_addr.s_addr = packet.yiaddr;
 					LOG(LOG_INFO, "Lease of %s obtained, lease time %ld",
 						inet_ntoa(temp_addr), lease);
 					start = now;
 					timeout = t1 + start;
 					requested_ip = packet.yiaddr;
 					run_script(&packet,
 						   ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));

 					state = BOUND;
 					change_mode(LISTEN_NONE);
 					if (client_config.quit_after_lease)
 						return(0);
 					if (!client_config.foreground)
 						client_background();

 				} else if (*message == DHCPNAK) {
 					/* return to init state */
 					LOG(LOG_INFO, "Received DHCP NAK");
 					run_script(&packet, "nak");
 					if (state != REQUESTING)
 						run_script(NULL, "deconfig");
 					state = INIT_SELECTING;
 					timeout = now;
 					requested_ip = 0;
 					packet_num = 0;
 					change_mode(LISTEN_RAW);
 					sleep(3); /* avoid excessive network traffic */
 				}
 				break;
 			/* case BOUND, RELEASED: - ignore all packets */
 			}
 		} else if (retval > 0 && FD_ISSET(udhcp_signal_pipe[0], &rfds)) {
 			if (read(udhcp_signal_pipe[0], &sig, sizeof(sig)) < 0) {
 				DEBUG(LOG_ERR, "Could not read signal: %m");
 				continue; /* probably just EINTR */
 			}
 			switch (sig) {
 			case SIGUSR1:
 				perform_renew();
 				break;
 			case SIGUSR2:
 				perform_release();
 				break;
 			case SIGTERM:
 				LOG(LOG_INFO, "Received SIGTERM");
 				return(0);
 			}
 		} else if (retval == -1 && errno == EINTR) {
 			/* a signal was caught */
 		} else {
 			/* An error occured */
 			DEBUG(LOG_ERR, "Error on select");
 		}

 	}
 	return 0;
 }
	/* dhcpc.c
	*
	* udhcp DHCP client
	*
	* Russ Dill <Russ.Dill@asu.edu> July 2001
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#include <sys/time.h>
	#include <sys/file.h>
	#include <unistd.h>
	#include <getopt.h>
	#include <stdlib.h>
	#include <sys/socket.h>
	#include <netinet/in.h>
	#include <arpa/inet.h>
	#include <signal.h>
	#include <time.h>
	#include <string.h>
	#include <sys/ioctl.h>
	#include <net/if.h>
	#include <errno.h>

	#include "dhcpd.h"
	#include "dhcpc.h"
	#include "options.h"
	#include "clientpacket.h"
	#include "script.h"
	#include "socket.h"
	#include "common.h"

	static int state;
	static unsigned long requested_ip; /* = 0 */
	static unsigned long server_addr;
	static unsigned long timeout;
	static int packet_num; /* = 0 */
	static int fd = -1;

	#define LISTEN_NONE 0
	#define LISTEN_KERNEL 1
	#define LISTEN_RAW 2
	static int listen_mode;

	#ifdef CONFIG_INSTALL_NO_USR
	#define DEFAULT_SCRIPT "/share/udhcpc/default.script"
	#else
	#define DEFAULT_SCRIPT "/usr/share/udhcpc/default.script"
	#endif

	struct client_config_t client_config = {
	/* Default options. */
	abort_if_no_lease: 0,
	foreground: 0,
	quit_after_lease: 0,
	background_if_no_lease: 0,
	interface: "eth0",
	pidfile: NULL,
	script: DEFAULT_SCRIPT,
	clientid: NULL,
	hostname: NULL,
	ifindex: 0,
	arp: "\0\0\0\0\0\0", /* appease gcc-3.0 */
	};

	/* just a little helper */
	static void change_mode(int new_mode)
	{
	DEBUG(LOG_INFO, "entering %s listen mode",
	new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
	if (fd >= 0) close(fd);
	fd = -1;
	listen_mode = new_mode;
	}


	/* perform a renew */
	static void perform_renew(void)
	{
	LOG(LOG_INFO, "Performing a DHCP renew");
	switch (state) {
	case BOUND:
	change_mode(LISTEN_KERNEL);
	case RENEWING:
	case REBINDING:
	state = RENEW_REQUESTED;
	break;
	case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
	run_script(NULL, "deconfig");
	case REQUESTING:
	case RELEASED:
	change_mode(LISTEN_RAW);
	state = INIT_SELECTING;
	break;
	case INIT_SELECTING:
	break;
	}

	/* start things over */
	packet_num = 0;

	/* Kill any timeouts because the user wants this to hurry along */
	timeout = 0;
	}


	/* perform a release */
	static void perform_release(void)
	{
	char buffer[16];
	struct in_addr temp_addr;

	/* send release packet */
	if (state == BOUND \|\| state == RENEWING \|\| state == REBINDING) {
	temp_addr.s_addr = server_addr;
	sprintf(buffer, "%s", inet_ntoa(temp_addr));
	temp_addr.s_addr = requested_ip;
	LOG(LOG_INFO, "Unicasting a release of %s to %s",
	inet_ntoa(temp_addr), buffer);
	send_release(server_addr, requested_ip); /* unicast */
	run_script(NULL, "deconfig");
	}
	LOG(LOG_INFO, "Entering released state");

	change_mode(LISTEN_NONE);
	state = RELEASED;
	timeout = 0x7fffffff;
	}


	static void client_background(void)
	{
	background(client_config.pidfile);
	client_config.foreground = 1; /* Do not fork again. */
	client_config.background_if_no_lease = 0;
	}


	int udhcpc_main(int argc, char *argv[])
	{
	unsigned char temp, message;
	unsigned long t1 = 0, t2 = 0, xid = 0;
	unsigned long start = 0, lease;
	fd_set rfds;
	int retval;
	struct timeval tv;
	int c, len;
	struct dhcpMessage packet;
	struct in_addr temp_addr;
	time_t now;
	int max_fd;
	int sig;

	static const struct option arg_options[] = {
	{"clientid", required_argument, 0, 'c'},
	{"foreground", no_argument, 0, 'f'},
	{"background", no_argument, 0, 'b'},
	{"hostname", required_argument, 0, 'H'},
	{"hostname", required_argument, 0, 'h'},
	{"interface", required_argument, 0, 'i'},
	{"now", no_argument, 0, 'n'},
	{"pidfile", required_argument, 0, 'p'},
	{"quit", no_argument, 0, 'q'},
	{"request", required_argument, 0, 'r'},
	{"script", required_argument, 0, 's'},
	{"version", no_argument, 0, 'v'},
	{0, 0, 0, 0}
	};

	/* get options */
	while (1) {
	int option_index = 0;
	c = getopt_long(argc, argv, "c:fbH:h:i:np:qr:s:v", arg_options, &option_index);
	if (c == -1) break;

	switch (c) {
	case 'c':
	len = strlen(optarg) > 255 ? 255 : strlen(optarg);
	if (client_config.clientid) free(client_config.clientid);
	client_config.clientid = xmalloc(len + 2);
	client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
	client_config.clientid[OPT_LEN] = len;
	client_config.clientid[OPT_DATA] = '\0';
	strncpy(client_config.clientid + OPT_DATA, optarg, len);
	break;
	case 'f':
	client_config.foreground = 1;
	break;
	case 'b':
	client_config.background_if_no_lease = 1;
	break;
	case 'h':
	case 'H':
	len = strlen(optarg) > 255 ? 255 : strlen(optarg);
	if (client_config.hostname) free(client_config.hostname);
	client_config.hostname = xmalloc(len + 2);
	client_config.hostname[OPT_CODE] = DHCP_HOST_NAME;
	client_config.hostname[OPT_LEN] = len;
	strncpy(client_config.hostname + 2, optarg, len);
	break;
	case 'i':
	client_config.interface = optarg;
	break;
	case 'n':
	client_config.abort_if_no_lease = 1;
	break;
	case 'p':
	client_config.pidfile = optarg;
	break;
	case 'q':
	client_config.quit_after_lease = 1;
	break;
	case 'r':
	requested_ip = inet_addr(optarg);
	break;
	case 's':
	client_config.script = optarg;
	break;
	case 'v':
	bb_error_msg("version %s\n", VERSION);
	return(0);
	break;
	default:
	bb_show_usage();
	}
	}

	start_log("client");
	if (read_interface(client_config.interface, &client_config.ifindex,
	NULL, client_config.arp) < 0)
	return(1);

	if (!client_config.clientid) {
	client_config.clientid = xmalloc(6 + 3);
	client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
	client_config.clientid[OPT_LEN] = 7;
	client_config.clientid[OPT_DATA] = 1;
	memcpy(client_config.clientid + 3, client_config.arp, 6);
	}

	/* setup signal handlers */
	udhcp_set_signal_pipe(SIGUSR2);

	state = INIT_SELECTING;
	run_script(NULL, "deconfig");
	change_mode(LISTEN_RAW);

	for (;;) {

	tv.tv_sec = timeout - time(0);
	tv.tv_usec = 0;
	FD_ZERO(&rfds);

	if (listen_mode != LISTEN_NONE && fd < 0) {
	if (listen_mode == LISTEN_KERNEL)
	fd = listen_socket(INADDR_ANY, CLIENT_PORT, client_config.interface);
	else
	fd = raw_socket(client_config.ifindex);
	if (fd < 0) {
	LOG(LOG_ERR, "FATAL: couldn't listen on socket, %m");
	return(0);
	}
	}
	if (fd >= 0) FD_SET(fd, &rfds);
	FD_SET(udhcp_signal_pipe[0], &rfds);

	if (tv.tv_sec > 0) {
	DEBUG(LOG_INFO, "Waiting on select...\n");
	max_fd = udhcp_signal_pipe[0] > fd ? udhcp_signal_pipe[0] : fd;
	retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
	} else retval = 0; /* If we already timed out, fall through */

	now = time(0);
	if (retval == 0) {
	/* timeout dropped to zero */
	switch (state) {
	case INIT_SELECTING:
	if (packet_num < 3) {
	if (packet_num == 0)
	xid = random_xid();

	/* send discover packet */
	send_discover(xid, requested_ip); /* broadcast */

	timeout = now + ((packet_num == 2) ? 4 : 2);
	packet_num++;
	} else {
	if (client_config.background_if_no_lease) {
	LOG(LOG_INFO, "No lease, forking to background.");
	client_background();
	} else if (client_config.abort_if_no_lease) {
	LOG(LOG_INFO, "No lease, failing.");
	return(1);
	}
	/* wait to try again */
	packet_num = 0;
	timeout = now + 60;
	}
	break;
	case RENEW_REQUESTED:
	case REQUESTING:
	if (packet_num < 3) {
	/* send request packet */
	if (state == RENEW_REQUESTED)
	send_renew(xid, server_addr, requested_ip); /* unicast */
	else send_selecting(xid, server_addr, requested_ip); /* broadcast */

	timeout = now + ((packet_num == 2) ? 10 : 2);
	packet_num++;
	} else {
	/* timed out, go back to init state */
	if (state == RENEW_REQUESTED) run_script(NULL, "deconfig");
	state = INIT_SELECTING;
	timeout = now;
	packet_num = 0;
	change_mode(LISTEN_RAW);
	}
	break;
	case BOUND:
	/* Lease is starting to run out, time to enter renewing state */
	state = RENEWING;
	change_mode(LISTEN_KERNEL);
	DEBUG(LOG_INFO, "Entering renew state");
	/* fall right through */
	case RENEWING:
	/* Either set a new T1, or enter REBINDING state */
	if ((t2 - t1) <= (lease / 14400 + 1)) {
	/* timed out, enter rebinding state */
	state = REBINDING;
	timeout = now + (t2 - t1);
	DEBUG(LOG_INFO, "Entering rebinding state");
	} else {
	/* send a request packet */
	send_renew(xid, server_addr, requested_ip); /* unicast */

	t1 = (t2 - t1) / 2 + t1;
	timeout = t1 + start;
	}
	break;
	case REBINDING:
	/* Either set a new T2, or enter INIT state */
	if ((lease - t2) <= (lease / 14400 + 1)) {
	/* timed out, enter init state */
	state = INIT_SELECTING;
	LOG(LOG_INFO, "Lease lost, entering init state");
	run_script(NULL, "deconfig");
	timeout = now;
	packet_num = 0;
	change_mode(LISTEN_RAW);
	} else {
	/* send a request packet */
	send_renew(xid, 0, requested_ip); /* broadcast */

	t2 = (lease - t2) / 2 + t2;
	timeout = t2 + start;
	}
	break;
	case RELEASED:
	/* yah, I know, you say it would never happen */
	timeout = 0x7fffffff;
	break;
	}
	} else if (retval > 0 && listen_mode != LISTEN_NONE && FD_ISSET(fd, &rfds)) {
	/* a packet is ready, read it */

	if (listen_mode == LISTEN_KERNEL)
	len = get_packet(&packet, fd);
	else len = get_raw_packet(&packet, fd);

	if (len == -1 && errno != EINTR) {
	DEBUG(LOG_INFO, "error on read, %m, reopening socket");
	change_mode(listen_mode); /* just close and reopen */
	}
	if (len < 0) continue;

	if (packet.xid != xid) {
	DEBUG(LOG_INFO, "Ignoring XID %lx (our xid is %lx)",
	(unsigned long) packet.xid, xid);
	continue;
	}

	if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
	DEBUG(LOG_ERR, "couldnt get option from packet -- ignoring");
	continue;
	}

	switch (state) {
	case INIT_SELECTING:
	/* Must be a DHCPOFFER to one of our xid's */
	if (*message == DHCPOFFER) {
	if ((temp = get_option(&packet, DHCP_SERVER_ID))) {
	memcpy(&server_addr, temp, 4);
	xid = packet.xid;
	requested_ip = packet.yiaddr;

	/* enter requesting state */
	state = REQUESTING;
	timeout = now;
	packet_num = 0;
	} else {
	DEBUG(LOG_ERR, "No server ID in message");
	}
	}
	break;
	case RENEW_REQUESTED:
	case REQUESTING:
	case RENEWING:
	case REBINDING:
	if (*message == DHCPACK) {
	if (!(temp = get_option(&packet, DHCP_LEASE_TIME))) {
	LOG(LOG_ERR, "No lease time with ACK, using 1 hour lease");
	lease = 60 * 60;
	} else {
	memcpy(&lease, temp, 4);
	lease = ntohl(lease);
	}

	/* enter bound state */
	t1 = lease / 2;

	/* little fixed point for n * .875 */
	t2 = (lease * 0x7) >> 3;
	temp_addr.s_addr = packet.yiaddr;
	LOG(LOG_INFO, "Lease of %s obtained, lease time %ld",
	inet_ntoa(temp_addr), lease);
	start = now;
	timeout = t1 + start;
	requested_ip = packet.yiaddr;
	run_script(&packet,
	((state == RENEWING \|\| state == REBINDING) ? "renew" : "bound"));

	state = BOUND;
	change_mode(LISTEN_NONE);
	if (client_config.quit_after_lease)
	return(0);
	if (!client_config.foreground)
	client_background();

	} else if (*message == DHCPNAK) {
	/* return to init state */
	LOG(LOG_INFO, "Received DHCP NAK");
	run_script(&packet, "nak");
	if (state != REQUESTING)
	run_script(NULL, "deconfig");
	state = INIT_SELECTING;
	timeout = now;
	requested_ip = 0;
	packet_num = 0;
	change_mode(LISTEN_RAW);
	sleep(3); /* avoid excessive network traffic */
	}
	break;
	/* case BOUND, RELEASED: - ignore all packets */
	}
	} else if (retval > 0 && FD_ISSET(udhcp_signal_pipe[0], &rfds)) {
	if (read(udhcp_signal_pipe[0], &sig, sizeof(sig)) < 0) {
	DEBUG(LOG_ERR, "Could not read signal: %m");
	continue; /* probably just EINTR */
	}
	switch (sig) {
	case SIGUSR1:
	perform_renew();
	break;
	case SIGUSR2:
	perform_release();
	break;
	case SIGTERM:
	LOG(LOG_INFO, "Received SIGTERM");
	return(0);
	}
	} else if (retval == -1 && errno == EINTR) {
	/* a signal was caught */
	} else {
	/* An error occured */
	DEBUG(LOG_ERR, "Error on select");
	}

	}
	return 0;
	}