networking/udhcp/dhcpc.c - codeaurora/busybox - Gitiles

 /* vi: set sw=4 ts=4: */
 /* dhcpc.c
  *
  * udhcp DHCP client
  *
  * Russ Dill <Russ.Dill@asu.edu> July 2001
  *
  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  */

 #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 "common.h"
 #include "dhcpd.h"
 #include "dhcpc.h"
 #include "options.h"
 #include "clientpacket.h"
 #include "clientsocket.h"
 #include "socket.h"
 #include "signalpipe.h"

 static int state;
 /* Something is definitely wrong here. IPv4 addresses
  * in variables of type long?? BTW, we use inet_ntoa()
  * in the code. Manpage says that struct in_addr has a member of type long (!)
  * which holds IPv4 address, and the struct is passed by value (!!)
  */
 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;

 struct client_config_t client_config = {
 	/* Default options. */
 	.abort_if_no_lease = 0,
 	.foreground = 0,
 	.quit_after_lease = 0,
 	.release_on_quit = 0,
 	.background_if_no_lease = 0,
 	.interface = "eth0",
 	.pidfile = NULL,
 	.script = DEFAULT_SCRIPT,
 	.clientid = NULL,
 	.vendorclass = NULL,
 	.hostname = NULL,
 	.fqdn = NULL,
 	.ifindex = 0,
 	.retries = 3,
 	.timeout = 3,
 	.arp = "\0\0\0\0\0\0",		/* appease gcc-3.0 */
 };

 /* just a little helper */
 static void change_mode(int new_mode)
 {
 	DEBUG("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)
 {
 	bb_info_msg("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 */
 		udhcp_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;
 		bb_info_msg("Unicasting a release of %s to %s",
 				inet_ntoa(temp_addr), buffer);
 		send_release(server_addr, requested_ip); /* unicast */
 		udhcp_run_script(NULL, "deconfig");
 	}
 	bb_info_msg("Entering released state");

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


 static void client_background(void)
 {
 	udhcp_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[])
 {
 	uint8_t *temp, *message;
 	unsigned long t1 = 0, t2 = 0, xid = 0;
 	unsigned long start = 0, lease = 0;
 	fd_set rfds;
 	int retval;
 	struct timeval tv;
 	int c, len;
 	struct dhcpMessage packet;
 	struct in_addr temp_addr;
 	long now;
 	int max_fd;
 	int sig;
 	int no_clientid = 0;

 	static const struct option arg_options[] = {
 		{"clientid",	required_argument,	0, 'c'},
 		{"clientid-none", no_argument,		0, 'C'},
 		{"vendorclass",	required_argument,	0, 'V'},
 		{"foreground",	no_argument,		0, 'f'},
 		{"background",	no_argument,		0, 'b'},
 		{"hostname",	required_argument,	0, 'H'},
 		{"hostname",	required_argument,	0, 'h'},
 		{"fqdn",	required_argument,	0, 'F'},
 		{"interface",	required_argument,	0, 'i'},
 		{"now",		no_argument,		0, 'n'},
 		{"pidfile",	required_argument,	0, 'p'},
 		{"quit",	no_argument,		0, 'q'},
 		{"release",	no_argument,		0, 'R'},
 		{"request",	required_argument,	0, 'r'},
 		{"script",	required_argument,	0, 's'},
 		{"timeout",	required_argument,	0, 'T'},
 		{"version",	no_argument,		0, 'v'},
 		{"retries",	required_argument,	0, 't'},
 		{0, 0, 0, 0}
 	};

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

 		switch (c) {
 		case 'c':
 			if (no_clientid) bb_show_usage();
 			len = strlen(optarg) > 255 ? 255 : strlen(optarg);
 			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((char*)client_config.clientid + OPT_DATA, optarg, len);
 			break;
 		case 'C':
 			if (client_config.clientid) bb_show_usage();
 			no_clientid = 1;
 			break;
 		case 'V':
 			len = strlen(optarg) > 255 ? 255 : strlen(optarg);
 			free(client_config.vendorclass);
 			client_config.vendorclass = xmalloc(len + 2);
 			client_config.vendorclass[OPT_CODE] = DHCP_VENDOR;
 			client_config.vendorclass[OPT_LEN] = len;
 			strncpy((char*)client_config.vendorclass + 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);
 			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((char*)client_config.hostname + 2, optarg, len);
 			break;
 		case 'F':
 			len = strlen(optarg) > 255 ? 255 : strlen(optarg);
 			free(client_config.fqdn);
 			client_config.fqdn = xmalloc(len + 5);
 			client_config.fqdn[OPT_CODE] = DHCP_FQDN;
 			client_config.fqdn[OPT_LEN] = len + 3;
 			/* Flags: 0000NEOS
 			S: 1 => Client requests Server to update A RR in DNS as well as PTR
 			O: 1 => Server indicates to client that DNS has been updated regardless
 			E: 1 => Name data is DNS format, i.e. <4>host<6>domain<4>com<0> not "host.domain.com"
 			N: 1 => Client requests Server to not update DNS
 			*/
 			client_config.fqdn[OPT_LEN + 1] = 0x1;
 			client_config.fqdn[OPT_LEN + 2] = 0;
 			client_config.fqdn[OPT_LEN + 3] = 0;
 			strncpy((char*)client_config.fqdn + 5, 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':
 			client_config.release_on_quit = 1;
 			break;
 		case 'r':
 			requested_ip = inet_addr(optarg);
 			break;
 		case 's':
 			client_config.script = optarg;
 			break;
 		case 'T':
 			client_config.timeout = xatoi_u(optarg);
 			break;
 		case 't':
 			client_config.retries = xatoi_u(optarg);
 			break;
 		case 'v':
 			printf("version %s\n\n", BB_VER);
 			return 0;
 			break;
 		default:
 			bb_show_usage();
 		}
 	}

 	/* Start the log, sanitize fd's, and write a pid file */
 	udhcp_start_log_and_pid(client_config.pidfile);

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

 	/* if not set, and not suppressed, setup the default client ID */
 	if (!client_config.clientid && !no_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);
 	}

 	if (!client_config.vendorclass) {
 		client_config.vendorclass = xmalloc(sizeof("udhcp "BB_VER) + 2);
 		client_config.vendorclass[OPT_CODE] = DHCP_VENDOR;
 		client_config.vendorclass[OPT_LEN] = sizeof("udhcp "BB_VER) - 1;
 		client_config.vendorclass[OPT_DATA] = 1;
 		memcpy(&client_config.vendorclass[OPT_DATA],
 			"udhcp "BB_VER, sizeof("udhcp "BB_VER) - 1);
 	}


 	/* setup the signal pipe */
 	udhcp_sp_setup();

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

 	for (;;) {

 		tv.tv_sec = timeout - uptime();
 		tv.tv_usec = 0;

 		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) {
 				bb_perror_msg("FATAL: cannot listen on socket");
 				return 0;
 			}
 		}
 		max_fd = udhcp_sp_fd_set(&rfds, fd);

 		if (tv.tv_sec > 0) {
 			DEBUG("Waiting on select...");
 			retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
 		} else retval = 0; /* If we already timed out, fall through */

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

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

 					timeout = now + client_config.timeout;
 					packet_num++;
 				} else {
 					udhcp_run_script(NULL, "leasefail");
 					if (client_config.background_if_no_lease) {
 						bb_info_msg("No lease, forking to background");
 						client_background();
 					} else if (client_config.abort_if_no_lease) {
 						bb_info_msg("No lease, failing");
 						return 1;
 					}
 					/* wait to try again */
 					packet_num = 0;
 					timeout = now + 60;
 				}
 				break;
 			case RENEW_REQUESTED:
 			case REQUESTING:
 				if (packet_num < client_config.retries) {
 					/* 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) udhcp_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("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("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;
 					bb_info_msg("Lease lost, entering init state");
 					udhcp_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 = udhcp_get_packet(&packet, fd);
 			else len = get_raw_packet(&packet, fd);

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

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

 			/* Ignore packets that aren't for us */
 			if (memcmp(packet.chaddr, client_config.arp, 6)) {
 				DEBUG("Packet does not have our chaddr - ignoring");
 				continue;
 			}

 			if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
 				bb_error_msg("cannot get option from packet - ignoring");
 				continue;
 			}

 			switch (state) {
 			case INIT_SELECTING:
 				/* Must be a DHCPOFFER to one of our xid's */
 				if (*message == DHCPOFFER) {
 					temp = get_option(&packet, DHCP_SERVER_ID);
 					if (temp) {
 						server_addr = *(uint32_t*)temp;
 						xid = packet.xid;
 						requested_ip = packet.yiaddr;

 						/* enter requesting state */
 						state = REQUESTING;
 						timeout = now;
 						packet_num = 0;
 					} else {
 						bb_error_msg("no server ID in message");
 					}
 				}
 				break;
 			case RENEW_REQUESTED:
 			case REQUESTING:
 			case RENEWING:
 			case REBINDING:
 				if (*message == DHCPACK) {
 					temp = get_option(&packet, DHCP_LEASE_TIME);
 					if (!temp) {
 						bb_error_msg("no lease time with ACK, using 1 hour lease");
 						lease = 60 * 60;
 					} else {
 						lease = ntohl(*(uint32_t*)temp);
 					}

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

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

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

 				} else if (*message == DHCPNAK) {
 					/* return to init state */
 					bb_info_msg("Received DHCP NAK");
 					udhcp_run_script(&packet, "nak");
 					if (state != REQUESTING)
 						udhcp_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 && (sig = udhcp_sp_read(&rfds))) {
 			switch (sig) {
 			case SIGUSR1:
 				perform_renew();
 				break;
 			case SIGUSR2:
 				perform_release();
 				break;
 			case SIGTERM:
 				bb_info_msg("Received SIGTERM");
 				if (client_config.release_on_quit)
 					perform_release();
 				return 0;
 			}
 		} else if (retval == -1 && errno == EINTR) {
 			/* a signal was caught */
 		} else {
 			/* An error occured */
 			bb_perror_msg("select");
 		}

 	}
 	return 0;
 }
	/* vi: set sw=4 ts=4: */
	/* dhcpc.c
	*
	* udhcp DHCP client
	*
	* Russ Dill <Russ.Dill@asu.edu> July 2001
	*
	* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
	*/

	#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 "common.h"
	#include "dhcpd.h"
	#include "dhcpc.h"
	#include "options.h"
	#include "clientpacket.h"
	#include "clientsocket.h"
	#include "socket.h"
	#include "signalpipe.h"

	static int state;
	/* Something is definitely wrong here. IPv4 addresses
	* in variables of type long?? BTW, we use inet_ntoa()
	* in the code. Manpage says that struct in_addr has a member of type long (!)
	* which holds IPv4 address, and the struct is passed by value (!!)
	*/
	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;

	struct client_config_t client_config = {
	/* Default options. */
	.abort_if_no_lease = 0,
	.foreground = 0,
	.quit_after_lease = 0,
	.release_on_quit = 0,
	.background_if_no_lease = 0,
	.interface = "eth0",
	.pidfile = NULL,
	.script = DEFAULT_SCRIPT,
	.clientid = NULL,
	.vendorclass = NULL,
	.hostname = NULL,
	.fqdn = NULL,
	.ifindex = 0,
	.retries = 3,
	.timeout = 3,
	.arp = "\0\0\0\0\0\0", /* appease gcc-3.0 */
	};

	/* just a little helper */
	static void change_mode(int new_mode)
	{
	DEBUG("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)
	{
	bb_info_msg("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 */
	udhcp_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;
	bb_info_msg("Unicasting a release of %s to %s",
	inet_ntoa(temp_addr), buffer);
	send_release(server_addr, requested_ip); /* unicast */
	udhcp_run_script(NULL, "deconfig");
	}
	bb_info_msg("Entering released state");

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


	static void client_background(void)
	{
	udhcp_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[])
	{
	uint8_t temp, message;
	unsigned long t1 = 0, t2 = 0, xid = 0;
	unsigned long start = 0, lease = 0;
	fd_set rfds;
	int retval;
	struct timeval tv;
	int c, len;
	struct dhcpMessage packet;
	struct in_addr temp_addr;
	long now;
	int max_fd;
	int sig;
	int no_clientid = 0;

	static const struct option arg_options[] = {
	{"clientid", required_argument, 0, 'c'},
	{"clientid-none", no_argument, 0, 'C'},
	{"vendorclass", required_argument, 0, 'V'},
	{"foreground", no_argument, 0, 'f'},
	{"background", no_argument, 0, 'b'},
	{"hostname", required_argument, 0, 'H'},
	{"hostname", required_argument, 0, 'h'},
	{"fqdn", required_argument, 0, 'F'},
	{"interface", required_argument, 0, 'i'},
	{"now", no_argument, 0, 'n'},
	{"pidfile", required_argument, 0, 'p'},
	{"quit", no_argument, 0, 'q'},
	{"release", no_argument, 0, 'R'},
	{"request", required_argument, 0, 'r'},
	{"script", required_argument, 0, 's'},
	{"timeout", required_argument, 0, 'T'},
	{"version", no_argument, 0, 'v'},
	{"retries", required_argument, 0, 't'},
	{0, 0, 0, 0}
	};

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

	switch (c) {
	case 'c':
	if (no_clientid) bb_show_usage();
	len = strlen(optarg) > 255 ? 255 : strlen(optarg);
	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((char*)client_config.clientid + OPT_DATA, optarg, len);
	break;
	case 'C':
	if (client_config.clientid) bb_show_usage();
	no_clientid = 1;
	break;
	case 'V':
	len = strlen(optarg) > 255 ? 255 : strlen(optarg);
	free(client_config.vendorclass);
	client_config.vendorclass = xmalloc(len + 2);
	client_config.vendorclass[OPT_CODE] = DHCP_VENDOR;
	client_config.vendorclass[OPT_LEN] = len;
	strncpy((char*)client_config.vendorclass + 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);
	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((char*)client_config.hostname + 2, optarg, len);
	break;
	case 'F':
	len = strlen(optarg) > 255 ? 255 : strlen(optarg);
	free(client_config.fqdn);
	client_config.fqdn = xmalloc(len + 5);
	client_config.fqdn[OPT_CODE] = DHCP_FQDN;
	client_config.fqdn[OPT_LEN] = len + 3;
	/* Flags: 0000NEOS
	S: 1 => Client requests Server to update A RR in DNS as well as PTR
	O: 1 => Server indicates to client that DNS has been updated regardless
	E: 1 => Name data is DNS format, i.e. <4>host<6>domain<4>com<0> not "host.domain.com"
	N: 1 => Client requests Server to not update DNS
	*/
	client_config.fqdn[OPT_LEN + 1] = 0x1;
	client_config.fqdn[OPT_LEN + 2] = 0;
	client_config.fqdn[OPT_LEN + 3] = 0;
	strncpy((char*)client_config.fqdn + 5, 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':
	client_config.release_on_quit = 1;
	break;
	case 'r':
	requested_ip = inet_addr(optarg);
	break;
	case 's':
	client_config.script = optarg;
	break;
	case 'T':
	client_config.timeout = xatoi_u(optarg);
	break;
	case 't':
	client_config.retries = xatoi_u(optarg);
	break;
	case 'v':
	printf("version %s\n\n", BB_VER);
	return 0;
	break;
	default:
	bb_show_usage();
	}
	}

	/* Start the log, sanitize fd's, and write a pid file */
	udhcp_start_log_and_pid(client_config.pidfile);

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

	/* if not set, and not suppressed, setup the default client ID */
	if (!client_config.clientid && !no_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);
	}

	if (!client_config.vendorclass) {
	client_config.vendorclass = xmalloc(sizeof("udhcp "BB_VER) + 2);
	client_config.vendorclass[OPT_CODE] = DHCP_VENDOR;
	client_config.vendorclass[OPT_LEN] = sizeof("udhcp "BB_VER) - 1;
	client_config.vendorclass[OPT_DATA] = 1;
	memcpy(&client_config.vendorclass[OPT_DATA],
	"udhcp "BB_VER, sizeof("udhcp "BB_VER) - 1);
	}


	/* setup the signal pipe */
	udhcp_sp_setup();

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

	for (;;) {

	tv.tv_sec = timeout - uptime();
	tv.tv_usec = 0;

	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) {
	bb_perror_msg("FATAL: cannot listen on socket");
	return 0;
	}
	}
	max_fd = udhcp_sp_fd_set(&rfds, fd);

	if (tv.tv_sec > 0) {
	DEBUG("Waiting on select...");
	retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
	} else retval = 0; /* If we already timed out, fall through */

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

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

	timeout = now + client_config.timeout;
	packet_num++;
	} else {
	udhcp_run_script(NULL, "leasefail");
	if (client_config.background_if_no_lease) {
	bb_info_msg("No lease, forking to background");
	client_background();
	} else if (client_config.abort_if_no_lease) {
	bb_info_msg("No lease, failing");
	return 1;
	}
	/* wait to try again */
	packet_num = 0;
	timeout = now + 60;
	}
	break;
	case RENEW_REQUESTED:
	case REQUESTING:
	if (packet_num < client_config.retries) {
	/* 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) udhcp_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("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("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;
	bb_info_msg("Lease lost, entering init state");
	udhcp_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 = udhcp_get_packet(&packet, fd);
	else len = get_raw_packet(&packet, fd);

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

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

	/* Ignore packets that aren't for us */
	if (memcmp(packet.chaddr, client_config.arp, 6)) {
	DEBUG("Packet does not have our chaddr - ignoring");
	continue;
	}

	if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
	bb_error_msg("cannot get option from packet - ignoring");
	continue;
	}

	switch (state) {
	case INIT_SELECTING:
	/* Must be a DHCPOFFER to one of our xid's */
	if (*message == DHCPOFFER) {
	temp = get_option(&packet, DHCP_SERVER_ID);
	if (temp) {
	server_addr = (uint32_t)temp;
	xid = packet.xid;
	requested_ip = packet.yiaddr;

	/* enter requesting state */
	state = REQUESTING;
	timeout = now;
	packet_num = 0;
	} else {
	bb_error_msg("no server ID in message");
	}
	}
	break;
	case RENEW_REQUESTED:
	case REQUESTING:
	case RENEWING:
	case REBINDING:
	if (*message == DHCPACK) {
	temp = get_option(&packet, DHCP_LEASE_TIME);
	if (!temp) {
	bb_error_msg("no lease time with ACK, using 1 hour lease");
	lease = 60 * 60;
	} else {
	lease = ntohl((uint32_t)temp);
	}

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

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

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

	} else if (*message == DHCPNAK) {
	/* return to init state */
	bb_info_msg("Received DHCP NAK");
	udhcp_run_script(&packet, "nak");
	if (state != REQUESTING)
	udhcp_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 && (sig = udhcp_sp_read(&rfds))) {
	switch (sig) {
	case SIGUSR1:
	perform_renew();
	break;
	case SIGUSR2:
	perform_release();
	break;
	case SIGTERM:
	bb_info_msg("Received SIGTERM");
	if (client_config.release_on_quit)
	perform_release();
	return 0;
	}
	} else if (retval == -1 && errno == EINTR) {
	/* a signal was caught */
	} else {
	/* An error occured */
	bb_perror_msg("select");
	}

	}
	return 0;
	}