New applet, udhcp client

5 files changed, 1590 insertions, 0 deletions

diff --git a/include/applets.h b/include/applets.h
index 6b8bce7..a1084fc 100644
--- a/include/applets.h
+++ b/include/applets.h
@@ -479,6 +479,9 @@
 #ifdef CONFIG_TTY
 	APPLET(tty, tty_main, _BB_DIR_USR_BIN, _BB_SUID_NEVER)
 #endif
+#ifdef CONFIG_UDHCPC
+	APPLET(udhcpc, udhcpc_main, _BB_DIR_SBIN, _BB_SUID_NEVER)
+#endif
 #ifdef CONFIG_UMOUNT
 	APPLET(umount, umount_main, _BB_DIR_BIN, _BB_SUID_NEVER)
 #endif
diff --git a/include/usage.h b/include/usage.h
index a232c88..a5ae4c8 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -1905,6 +1905,20 @@
 	"$ tty\n" \
 	"/dev/tty2\n"
 
+#define udhcpc_trivial_usage \
+	"[-fqv] [-c CLIENTID] [-H HOSTNAME] [-i INTERFACE]\n\[-p file] [-r IP] [-s script]"
+#define udhcpc_full_usage \
+	"\t-c,\t--clientid=CLIENTID\tClient identifier\n" \
+	"\t-H,\t--hostname=HOSTNAME\tClient hostname\n" \
+	"\t-f,\t--foreground\tDo not fork after getting lease\n" \
+	"\t-i,\t--interface=INTERFACE\tInterface to use (default: eth0)\n" \
+	"\t-n,\t--now\tExit with failure if lease cannot be immediately negotiated.\n" \
+	"\t-p,\t--pidfile=file\tStore process ID of daemon in file\n" \
+	"\t-q,\t--quit\tQuit after obtaining lease\n" \
+	"\t-r,\t--request=IP\tIP address to request (default: none)\n" \
+	"\t-s,\t--script=file\tRun file at dhcp events (default: /usr/share/udhcpc/default.script)\n" \
+	"\t-v,\t--version\tDisplay version"
+
 #ifdef CONFIG_FEATURE_MOUNT_FORCE
   #define USAGE_MOUNT_FORCE(a) a
 #else
diff --git a/networking/Makefile.in b/networking/Makefile.in
index be4b53b..425b5d3 100644
--- a/networking/Makefile.in
+++ b/networking/Makefile.in
@@ -34,6 +34,7 @@ NETWORKING-$(CONFIG_ROUTE)		+= route.o
 NETWORKING-$(CONFIG_TELNET)		+= telnet.o
 NETWORKING-$(CONFIG_TFTP)		+= tftp.o
 NETWORKING-$(CONFIG_TRACEROUTE)		+= traceroute.o
+NETWORKING-$(CONFIG_UDHCPC)		+= udhcpc.o
 NETWORKING-$(CONFIG_WGET)		+= wget.o
 
 libraries-y+=$(NETWORKING_DIR)$(NETWORKING_AR)
diff --git a/networking/config.in b/networking/config.in
index 1edc1de..bc11d83 100644
--- a/networking/config.in
+++ b/networking/config.in
@@ -46,6 +46,7 @@ if [ "$CONFIG_TRACEROUTE" = "y" ]; then
     bool '  Enable verbose output'			CONFIG_FEATURE_TRACEROUTE_VERBOSE
     bool '  Enable SO_DEBUG option'	CONFIG_FEATURE_TRACEROUTE_SO_DEBUG
 fi
+bool 'udhcpc'       CONFIG_UDHCPC
 bool 'wget'	    CONFIG_WGET
 if [ "$CONFIG_WGET" = "y" ]; then
     bool '  Enable a nifty process meter (+2k)'	CONFIG_FEATURE_WGET_STATUSBAR
diff --git a/networking/udhcpc.c b/networking/udhcpc.c
new file mode 100644
index 0000000..f13d44d
--- /dev/null
+++ b/networking/udhcpc.c
@@ -0,0 +1,1571 @@
+/* dhcpd.c
+ *
+ * udhcp DHCP client
+ *
+ * Russ Dill <Russ.Dill@asu.edu> July 2001
+ * 
+ * Converted to busybox by Glenn McGrath August 2002
+ *
+ * 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 <stdio.h>
+#include <sys/time.h>
+#include <sys/types.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 <netinet/ip.h>
+#include <netinet/udp.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+       
+#if __GLIBC__ >=2 && __GLIBC_MINOR >= 1
+#include <netpacket/packet.h>
+#include <net/ethernet.h>
+#else
+#include <asm/types.h>
+#include <linux/if_packet.h>
+#include <linux/if_ether.h>
+#endif
+#include "libbb.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_main;
+#define DEBUG
+
+#define VERSION "0.9.7"
+
+#define LISTEN_NONE 0
+#define LISTEN_KERNEL 1
+#define LISTEN_RAW 2
+static int listen_mode;
+
+#define DEFAULT_SCRIPT	"/usr/share/udhcpc/default.script"
+
+#define DHCP_END		0xFF
+#define TYPE_MASK	0x0F
+#define BROADCAST_FLAG		0x8000
+
+#define SERVER_PORT		67
+
+#define DHCP_MAGIC		0x63825363
+
+#define BOOTREQUEST		1
+#define BOOTREPLY		2
+
+#define ETH_10MB		1
+#define ETH_10MB_LEN		6
+
+#define OPTION_FIELD		0
+#define FILE_FIELD		1
+#define SNAME_FIELD		2
+
+#define INIT_SELECTING	0
+#define REQUESTING	1
+#define BOUND		2
+#define RENEWING	3
+#define REBINDING	4
+#define INIT_REBOOT	5
+#define RENEW_REQUESTED 6
+#define RELEASED	7
+
+#define CLIENT_PORT		68
+
+#define DHCPDISCOVER		1
+#define DHCPOFFER		2
+#define DHCPREQUEST		3
+#define DHCPDECLINE		4
+#define DHCPACK			5
+#define DHCPNAK			6
+#define DHCPRELEASE		7
+#define DHCPINFORM		8
+
+/* DHCP option codes (partial list) */
+#define DHCP_PADDING		0x00
+#define DHCP_SUBNET		0x01
+#define DHCP_TIME_OFFSET	0x02
+#define DHCP_ROUTER		0x03
+#define DHCP_TIME_SERVER	0x04
+#define DHCP_NAME_SERVER	0x05
+#define DHCP_DNS_SERVER		0x06
+#define DHCP_LOG_SERVER		0x07
+#define DHCP_COOKIE_SERVER	0x08
+#define DHCP_LPR_SERVER		0x09
+#define DHCP_HOST_NAME		0x0c
+#define DHCP_BOOT_SIZE		0x0d
+#define DHCP_DOMAIN_NAME	0x0f
+#define DHCP_SWAP_SERVER	0x10
+#define DHCP_ROOT_PATH		0x11
+#define DHCP_IP_TTL		0x17
+#define DHCP_MTU		0x1a
+#define DHCP_BROADCAST		0x1c
+#define DHCP_NTP_SERVER		0x2a
+#define DHCP_WINS_SERVER	0x2c
+#define DHCP_REQUESTED_IP	0x32
+#define DHCP_LEASE_TIME		0x33
+#define DHCP_OPTION_OVER	0x34
+#define DHCP_MESSAGE_TYPE	0x35
+#define DHCP_SERVER_ID		0x36
+#define DHCP_PARAM_REQ		0x37
+#define DHCP_MESSAGE		0x38
+#define DHCP_MAX_SIZE		0x39
+#define DHCP_T1			0x3a
+#define DHCP_T2			0x3b
+#define DHCP_VENDOR		0x3c
+#define DHCP_CLIENT_ID		0x3d
+
+/* miscellaneous defines */
+#define MAC_BCAST_ADDR		(unsigned char *) "\xff\xff\xff\xff\xff\xff"
+#define OPT_CODE 0
+#define OPT_LEN 1
+#define OPT_DATA 2
+
+enum {
+	OPTION_IP=1,
+	OPTION_IP_PAIR,
+	OPTION_STRING,
+	OPTION_BOOLEAN,
+	OPTION_U8,
+	OPTION_U16,
+	OPTION_S16,
+	OPTION_U32,
+	OPTION_S32
+};
+
+#define OPTION_REQ	0x10 /* have the client request this option */
+#define OPTION_LIST	0x20 /* There can be a list of 1 or more of these */
+
+#ifdef SYSLOG
+# define LOG(level, str, args...) do { printf(str, ## args); \
+				printf("\n"); \
+				syslog(level, str, ## args); } while(0)
+# define OPEN_LOG(name) openlog(name, 0, 0)
+#define CLOSE_LOG() closelog()
+#else
+# define LOG_EMERG	"EMERGENCY!"
+# define LOG_ALERT	"ALERT!"
+# define LOG_CRIT	"critical!"
+# define LOG_WARNING	"warning"
+# define LOG_ERR	"error"
+# define LOG_INFO	"info"
+# define LOG_DEBUG	"debug"
+# define LOG(level, str, args...) do { printf("%s, ", level); printf(str, ## args); printf("\n"); } while(0)
+# define OPEN_LOG(name) do {;} while(0)
+#define CLOSE_LOG() do {;} while(0)
+#endif
+
+#ifdef DEBUG
+# undef DEBUG
+# define DEBUG(level, str, args...) LOG(level, str, ## args)
+# define DEBUGGING
+#else
+# define DEBUG(level, str, args...) do {;} while(0)
+#endif
+
+struct client_config_t {
+	char foreground;		/* Do not fork */
+	char quit_after_lease;		/* Quit after obtaining lease */
+	char abort_if_no_lease;		/* Abort if no lease */
+	char *interface;		/* The name of the interface to use */
+	char *pidfile;			/* Optionally store the process ID */
+	char *script;			/* User script to run at dhcp events */
+	unsigned char *clientid;	/* Optional client id to use */
+	unsigned char *hostname;	/* Optional hostname to use */
+	int ifindex;			/* Index number of the interface to use */
+	unsigned char arp[6];		/* Our arp address */
+};
+extern struct client_config_t client_config;
+
+struct dhcpMessage {
+	u_int8_t op;
+	u_int8_t htype;
+	u_int8_t hlen;
+	u_int8_t hops;
+	u_int32_t xid;
+	u_int16_t secs;
+	u_int16_t flags;
+	u_int32_t ciaddr;
+	u_int32_t yiaddr;
+	u_int32_t siaddr;
+	u_int32_t giaddr;
+	u_int8_t chaddr[16];
+	u_int8_t sname[64];
+	u_int8_t file[128];
+	u_int32_t cookie;
+	u_int8_t options[308]; /* 312 - cookie */ 
+};
+
+struct client_config_t client_config = {
+	/* Default options. */
+	abort_if_no_lease: 0,
+	foreground: 0,
+	quit_after_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 */
+};
+
+struct dhcp_option {
+	char name[10];
+	char flags;
+	unsigned char code;
+};
+
+struct udp_dhcp_packet {
+	struct iphdr ip;
+	struct udphdr udp;
+	struct dhcpMessage data;
+};
+
+struct dhcp_option options[] = {
+	/* name[10]	flags					code */
+	{"subnet",	OPTION_IP | OPTION_REQ,			0x01},
+	{"timezone",	OPTION_S32,				0x02},
+	{"router",	OPTION_IP | OPTION_LIST | OPTION_REQ,	0x03},
+	{"timesvr",	OPTION_IP | OPTION_LIST,		0x04},
+	{"namesvr",	OPTION_IP | OPTION_LIST,		0x05},
+	{"dns",		OPTION_IP | OPTION_LIST | OPTION_REQ,	0x06},
+	{"logsvr",	OPTION_IP | OPTION_LIST,		0x07},
+	{"cookiesvr",	OPTION_IP | OPTION_LIST,		0x08},
+	{"lprsvr",	OPTION_IP | OPTION_LIST,		0x09},
+	{"hostname",	OPTION_STRING | OPTION_REQ,		0x0c},
+	{"bootsize",	OPTION_U16,				0x0d},
+	{"domain",	OPTION_STRING | OPTION_REQ,		0x0f},
+	{"swapsvr",	OPTION_IP,				0x10},
+	{"rootpath",	OPTION_STRING,				0x11},
+	{"ipttl",	OPTION_U8,				0x17},
+	{"mtu",		OPTION_U16,				0x1a},
+	{"broadcast",	OPTION_IP | OPTION_REQ,			0x1c},
+	{"ntpsrv",	OPTION_IP | OPTION_LIST,		0x2a},
+	{"wins",	OPTION_IP | OPTION_LIST,		0x2c},
+	{"requestip",	OPTION_IP,				0x32},
+	{"lease",	OPTION_U32,				0x33},
+	{"dhcptype",	OPTION_U8,				0x35},
+	{"serverid",	OPTION_IP,				0x36},
+	{"message",	OPTION_STRING,				0x38},
+	{"tftp",	OPTION_STRING,				0x42},
+	{"bootfile",	OPTION_STRING,				0x43},
+	{"",		0x00,				0x00}
+};
+
+/* Lengths of the different option types */
+int option_lengths[] = {
+	[OPTION_IP] =		4,
+	[OPTION_IP_PAIR] =	8,
+	[OPTION_BOOLEAN] =	1,
+	[OPTION_STRING] =	1,
+	[OPTION_U8] =		1,
+	[OPTION_U16] =		2,
+	[OPTION_S16] =		2,
+	[OPTION_U32] =		4,
+	[OPTION_S32] =		4
+};
+
+/* get a rough idea of how long an option will be (rounding up...) */
+static int max_option_length[] = {
+	[OPTION_IP] =		sizeof("255.255.255.255 "),
+	[OPTION_IP_PAIR] =	sizeof("255.255.255.255 ") * 2,
+	[OPTION_STRING] =	1,
+	[OPTION_BOOLEAN] =	sizeof("yes "),
+	[OPTION_U8] =		sizeof("255 "),
+	[OPTION_U16] =		sizeof("65535 "),
+	[OPTION_S16] =		sizeof("-32768 "),
+	[OPTION_U32] =		sizeof("4294967295 "),
+	[OPTION_S32] =		sizeof("-2147483684 "),
+};
+
+static void print_usage(void)
+{
+	printf(
+"Usage: udhcpcd [OPTIONS]\n\n"
+"  -c, --clientid=CLIENTID         Client identifier\n"
+"  -H, --hostname=HOSTNAME         Client hostname\n"
+"  -f, --foreground                Do not fork after getting lease\n"
+"  -i, --interface=INTERFACE       Interface to use (default: eth0)\n"
+"  -n, --now                       Exit with failure if lease cannot be\n"
+"                                  immediately negotiated.\n"
+"  -p, --pidfile=file              Store process ID of daemon in file\n"
+"  -q, --quit                      Quit after obtaining lease\n"
+"  -r, --request=IP                IP address to request (default: none)\n"
+"  -s, --script=file               Run file at dhcp events (default:\n"
+"                                  " DEFAULT_SCRIPT ")\n"
+"  -v, --version                   Display version\n"
+	);
+}
+/* return the position of the 'end' option (no bounds checking) */
+int end_option(unsigned char *optionptr) 
+{
+	int i = 0;
+	
+	while (optionptr[i] != DHCP_END) {
+		if (optionptr[i] == DHCP_PADDING) i++;
+		else i += optionptr[i + OPT_LEN] + 2;
+	}
+	return i;
+}
+
+/* add an option string to the options (an option string contains an option code,
+ * length, then data) */
+int add_option_string(unsigned char *optionptr, unsigned char *string)
+{
+	int end = end_option(optionptr);
+	
+	/* end position + string length + option code/length + end option */
+	if (end + string[OPT_LEN] + 2 + 1 >= 308) {
+		LOG(LOG_ERR, "Option 0x%02x did not fit into the packet!", string[OPT_CODE]);
+		return 0;
+	}
+	DEBUG(LOG_INFO, "adding option 0x%02x", string[OPT_CODE]);
+	memcpy(optionptr + end, string, string[OPT_LEN] + 2);
+	optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
+	return string[OPT_LEN] + 2;
+}
+
+/* add a one to four byte option to a packet */
+int add_simple_option(unsigned char *optionptr, unsigned char code, u_int32_t data)
+{
+	char length = 0;
+	int i;
+	unsigned char option[2 + 4];
+	unsigned char *u8;
+	u_int16_t *u16;
+	u_int32_t *u32;
+	u_int32_t aligned;
+	u8 = (unsigned char *) &aligned;
+	u16 = (u_int16_t *) &aligned;
+	u32 = &aligned;
+
+	for (i = 0; options[i].code; i++)
+		if (options[i].code == code) {
+			length = option_lengths[options[i].flags & TYPE_MASK];
+		}
+		
+	if (!length) {
+		DEBUG(LOG_ERR, "Could not add option 0x%02x", code);
+		return 0;
+	}
+	
+	option[OPT_CODE] = code;
+	option[OPT_LEN] = length;
+
+	switch (length) {
+		case 1: *u8 =  data; break;
+		case 2: *u16 = data; break;
+		case 4: *u32 = data; break;
+	}
+
+	memcpy(option + 2, &aligned, length);
+	return add_option_string(optionptr, option);
+}
+#if 0
+void init_header(struct dhcpMessage *packet, char type)
+{
+	memset(packet, 0, sizeof(struct dhcpMessage));
+	switch (type) {
+	case DHCPDISCOVER:
+	case DHCPREQUEST:
+	case DHCPRELEASE:
+	case DHCPINFORM:
+		packet->op = BOOTREQUEST;
+		break;
+	case DHCPOFFER:
+	case DHCPACK:
+	case DHCPNAK:
+		packet->op = BOOTREPLY;
+	}
+	packet->htype = ETH_10MB;
+	packet->hlen = ETH_10MB_LEN;
+	packet->cookie = htonl(DHCP_MAGIC);
+	packet->options[0] = DHCP_END;
+	add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type);
+}
+#endif
+u_int16_t checksum(void *addr, int count)
+{
+	/* Compute Internet Checksum for "count" bytes
+	 *         beginning at location "addr".
+	 */
+	register int32_t sum = 0;
+	u_int16_t *source = (u_int16_t *) addr;
+
+	while( count > 1 )  {
+		/*  This is the inner loop */
+		sum += *source++;
+		count -= 2;
+	}
+
+	/*  Add left-over byte, if any */
+	if( count > 0 )
+		sum += * (unsigned char *) source;
+
+	/*  Fold 32-bit sum to 16 bits */
+	while (sum>>16)
+		sum = (sum & 0xffff) + (sum >> 16);
+
+	return ~sum;
+}
+
+/* Constuct a ip/udp header for a packet, and specify the source and dest hardware address */
+int raw_packet(struct dhcpMessage *payload, u_int32_t source_ip, int source_port,
+		   u_int32_t dest_ip, int dest_port, unsigned char *dest_arp, int ifindex)
+{
+	int l_fd;
+	int result;
+	struct sockaddr_ll dest;
+	struct udp_dhcp_packet packet;
+
+	if ((l_fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
+		DEBUG(LOG_ERR, "socket call failed: %s", sys_errlist[errno]);
+		return -1;
+	}
+	
+	memset(&dest, 0, sizeof(dest));
+	memset(&packet, 0, sizeof(packet));
+	
+	dest.sll_family = AF_PACKET;
+	dest.sll_protocol = htons(ETH_P_IP);
+	dest.sll_ifindex = ifindex;
+	dest.sll_halen = 6;
+	memcpy(dest.sll_addr, dest_arp, 6);
+	if (bind(l_fd, (struct sockaddr *)&dest, sizeof(struct sockaddr_ll)) < 0) {
+		DEBUG(LOG_ERR, "bind call failed: %s", sys_errlist[errno]);
+		close(l_fd);
+		return -1;
+	}
+
+	packet.ip.protocol = IPPROTO_UDP;
+	packet.ip.saddr = source_ip;
+	packet.ip.daddr = dest_ip;
+	packet.udp.source = htons(source_port);
+	packet.udp.dest = htons(dest_port);
+	packet.udp.len = htons(sizeof(packet.udp) + sizeof(struct dhcpMessage)); /* cheat on the psuedo-header */
+	packet.ip.tot_len = packet.udp.len;
+	memcpy(&(packet.data), payload, sizeof(struct dhcpMessage));
+	packet.udp.check = checksum(&packet, sizeof(struct udp_dhcp_packet));
+	
+	packet.ip.tot_len = htons(sizeof(struct udp_dhcp_packet));
+	packet.ip.ihl = sizeof(packet.ip) >> 2;
+	packet.ip.version = IPVERSION;
+	packet.ip.ttl = IPDEFTTL;
+	packet.ip.check = checksum(&(packet.ip), sizeof(packet.ip));
+
+	result = sendto(l_fd, &packet, sizeof(struct udp_dhcp_packet), 0, (struct sockaddr *) &dest, sizeof(dest));
+	if (result <= 0) {
+		DEBUG(LOG_ERR, "write on socket failed: %s", sys_errlist[errno]);
+	}
+	close(l_fd);
+	return result;
+}
+
+/* Let the kernel do all the work for packet generation */
+int kernel_packet(struct dhcpMessage *payload, u_int32_t source_ip, int source_port,
+		   u_int32_t dest_ip, int dest_port)
+{
+	int n = 1;
+	int l_fd, result;
+	struct sockaddr_in client;
+	
+	if ((l_fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
+		return -1;
+	
+	if (setsockopt(l_fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) == -1)
+		return -1;
+
+	memset(&client, 0, sizeof(client));
+	client.sin_family = AF_INET;
+	client.sin_port = htons(source_port);
+	client.sin_addr.s_addr = source_ip;
+
+	if (bind(l_fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1)
+		return -1;
+
+	memset(&client, 0, sizeof(client));
+	client.sin_family = AF_INET;
+	client.sin_port = htons(dest_port);
+	client.sin_addr.s_addr = dest_ip; 
+
+	if (connect(l_fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1)
+		return -1;
+
+	result = write(l_fd, payload, sizeof(struct dhcpMessage));
+	close(l_fd);
+	return result;
+}
+
+/* initialize a packet with the proper defaults */
+static void init_packet(struct dhcpMessage *packet, char type)
+{
+	struct vendor  {
+		char vendor, length;
+		char str[sizeof("udhcp "VERSION)];
+	} vendor_id = { DHCP_VENDOR,  sizeof("udhcp "VERSION) - 1, "udhcp "VERSION};
+	
+//	init_header(packet, type);
+	memset(packet, 0, sizeof(struct dhcpMessage));
+	switch (type) {
+	case DHCPDISCOVER:
+	case DHCPREQUEST:
+	case DHCPRELEASE:
+	case DHCPINFORM:
+		packet->op = BOOTREQUEST;
+		break;
+	case DHCPOFFER:
+	case DHCPACK:
+	case DHCPNAK:
+		packet->op = BOOTREPLY;
+	}
+	packet->htype = ETH_10MB;
+	packet->hlen = ETH_10MB_LEN;
+	packet->cookie = htonl(DHCP_MAGIC);
+	packet->options[0] = DHCP_END;
+	add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type);
+
+	memcpy(packet->chaddr, client_config.arp, 6);
+	add_option_string(packet->options, client_config.clientid);
+	if (client_config.hostname) add_option_string(packet->options, client_config.hostname);
+	add_option_string(packet->options, (unsigned char *) &vendor_id);
+}
+
+
+/* Add a paramater request list for stubborn DHCP servers. Pull the data
+ * from the struct in options.c. Don't do bounds checking here because it
+ * goes towards the head of the packet. */
+static void add_requests(struct dhcpMessage *packet)
+{
+	int end = end_option(packet->options);
+	int i, len = 0;
+	
+	packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
+	for (i = 0; options[i].code; i++)
+		if (options[i].flags & OPTION_REQ)
+			packet->options[end + OPT_DATA + len++] = options[i].code;
+	packet->options[end + OPT_LEN] = len;
+	packet->options[end + OPT_DATA + len] = DHCP_END;
+
+}
+
+/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
+int send_discover(unsigned long xid, unsigned long requested)
+{
+	struct dhcpMessage packet;
+
+	init_packet(&packet, DHCPDISCOVER);
+	packet.xid = xid;
+	if (requested)
+		add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
+
+	add_requests(&packet);
+	LOG(LOG_DEBUG, "Sending discover...");
+	return raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, 
+				SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
+}
+
+/* Broadcasts a DHCP request message */
+int send_selecting(unsigned long xid, unsigned long server, unsigned long requested)
+{
+	struct dhcpMessage packet;
+	struct in_addr addr;
+
+	init_packet(&packet, DHCPREQUEST);
+	packet.xid = xid;
+
+	add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
+	add_simple_option(packet.options, DHCP_SERVER_ID, server);
+	
+	add_requests(&packet);
+	addr.s_addr = requested;
+	LOG(LOG_DEBUG, "Sending select for %s...", inet_ntoa(addr));
+	return raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, 
+				SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
+}
+
+
+/* Unicasts or broadcasts a DHCP renew message */
+int send_renew(unsigned long xid, unsigned long server, unsigned long ciaddr)
+{
+	struct dhcpMessage packet;
+	int ret = 0;
+
+	init_packet(&packet, DHCPREQUEST);
+	packet.xid = xid;
+	packet.ciaddr = ciaddr;
+
+	add_requests(&packet);
+	LOG(LOG_DEBUG, "Sending renew...");
+	if (server) 
+		ret = kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
+	else ret = raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
+				SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
+	return ret;
+}	
+
+/* Create a random xid */
+unsigned long random_xid(void)
+{
+	static int initialized;
+	if (!initialized) {
+		srand(time(0));
+		initialized++;
+	}
+	return rand();
+}
+#if 0
+/* Unicasts a DHCP release message */
+int send_release(unsigned long server, unsigned long ciaddr)
+{
+	struct dhcpMessage packet;
+
+	init_packet(&packet, DHCPRELEASE);
+	packet.xid = random_xid();
+	packet.ciaddr = ciaddr;
+	
+	add_simple_option(packet.options, DHCP_REQUESTED_IP, ciaddr);
+	add_simple_option(packet.options, DHCP_SERVER_ID, server);
+
+	LOG(LOG_DEBUG, "Sending release...");
+	return kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
+}
+#endif
+
+/* 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");
+	close(fd_main);
+	fd_main = -1;
+	listen_mode = new_mode;
+}
+
+
+/* SIGUSR1 handler (renew) */
+static void renew_requested(int sig)
+{
+	sig = 0;
+	LOG(LOG_INFO, "Received SIGUSR1");
+	if (state == BOUND || state == RENEWING || state == REBINDING ||
+	    state == RELEASED) {
+	    	change_mode(LISTEN_KERNEL);
+		packet_num = 0;
+		state = RENEW_REQUESTED;
+	}
+
+	if (state == RELEASED) {
+		change_mode(LISTEN_RAW);
+		state = INIT_SELECTING;
+	}
+
+	/* Kill any timeouts because the user wants this to hurry along */
+	timeout = 0;
+}
+
+/* get an option with bounds checking (warning, not aligned). */
+unsigned char *get_option(struct dhcpMessage *packet, int code)
+{
+	int i, length;
+	unsigned char *optionptr;
+	int over = 0, done = 0, curr = OPTION_FIELD;
+	
+	optionptr = packet->options;
+	i = 0;
+	length = 308;
+	while (!done) {
+		if (i >= length) {
+			LOG(LOG_WARNING, "bogus packet, option fields too long.");
+			return NULL;
+		}
+		if (optionptr[i + OPT_CODE] == code) {
+			if (i + 1 + optionptr[i + OPT_LEN] >= length) {
+				LOG(LOG_WARNING, "bogus packet, option fields too long.");
+				return NULL;
+			}
+			return optionptr + i + 2;
+		}			
+		switch (optionptr[i + OPT_CODE]) {
+		case DHCP_PADDING:
+			i++;
+			break;
+		case DHCP_OPTION_OVER:
+			if (i + 1 + optionptr[i + OPT_LEN] >= length) {
+				LOG(LOG_WARNING, "bogus packet, option fields too long.");
+				return NULL;
+			}
+			over = optionptr[i + 3];
+			i += optionptr[OPT_LEN] + 2;
+			break;
+		case DHCP_END:
+			if (curr == OPTION_FIELD && over & FILE_FIELD) {
+				optionptr = packet->file;
+				i = 0;
+				length = 128;
+				curr = FILE_FIELD;
+			} else if (curr == FILE_FIELD && over & SNAME_FIELD) {
+				optionptr = packet->sname;
+				i = 0;
+				length = 64;
+				curr = SNAME_FIELD;
+			} else done = 1;
+			break;
+		default:
+			i += optionptr[OPT_LEN + i] + 2;
+		}
+	}
+	return NULL;
+}
+#if 0
+static int upper_length(int length, struct dhcp_option *option)
+{
+	return max_option_length[option->flags & TYPE_MASK] *
+	       (length / option_lengths[option->flags & TYPE_MASK]);
+}
+#endif
+
+static int sprintip(char *dest, char *pre, unsigned char *ip) {
+	return sprintf(dest, "%s%d.%d.%d.%d ", pre, ip[0], ip[1], ip[2], ip[3]);
+}
+
+
+/* Fill dest with the text of option 'option'. */
+static void fill_options(char *dest, unsigned char *option, struct dhcp_option *type_p)
+{
+	int type, optlen;
+	u_int16_t val_u16;
+	int16_t val_s16;
+	u_int32_t val_u32;
+	int32_t val_s32;
+	int len = option[OPT_LEN - 2];
+
+	dest += sprintf(dest, "%s=", type_p->name);
+
+	type = type_p->flags & TYPE_MASK;
+	optlen = option_lengths[type];
+	for(;;) {
+		switch (type) {
+		case OPTION_IP_PAIR:
+			dest += sprintip(dest, "", option);
+			*(dest++) = '/';
+			option += 4;
+			optlen = 4;
+		case OPTION_IP:	/* Works regardless of host byte order. */
+			dest += sprintip(dest, "", option);
+ 			break;
+		case OPTION_BOOLEAN:
+			dest += sprintf(dest, *option ? "yes " : "no ");
+			break;
+		case OPTION_U8:
+			dest += sprintf(dest, "%u ", *option);
+			break;
+		case OPTION_U16:
+			memcpy(&val_u16, option, 2);
+			dest += sprintf(dest, "%u ", ntohs(val_u16));
+			break;
+		case OPTION_S16:
+			memcpy(&val_s16, option, 2);
+			dest += sprintf(dest, "%d ", ntohs(val_s16));
+			break;
+		case OPTION_U32:
+			memcpy(&val_u32, option, 4);
+			dest += sprintf(dest, "%lu ", (unsigned long) ntohl(val_u32));
+			break;
+		case OPTION_S32:
+			memcpy(&val_s32, option, 4);
+			dest += sprintf(dest, "%ld ", (long) ntohl(val_s32));
+			break;
+		case OPTION_STRING:
+			memcpy(dest, option, len);
+			dest[len] = '\0';
+			return;	 /* Short circuit this case */
+		}
+		option += optlen;
+		len -= optlen;
+		if (len <= 0) break;
+	}
+}
+
+static char *find_env(const char *prefix, char *defaultstr)
+{
+	extern char **environ;
+	char **ptr;
+	const int len = strlen(prefix);
+
+	for (ptr = environ; *ptr != NULL; ptr++) {
+		if (strncmp(prefix, *ptr, len) == 0)
+			return *ptr;
+	}
+	return defaultstr;
+}
+
+/* put all the paramaters into an environment */
+static char **fill_envp(struct dhcpMessage *packet)
+{
+	/* supported options are easily added here */
+	int num_options = 0;
+	int i, j;
+	char **envp;
+	unsigned char *temp;
+	char over = 0;
+
+	if (packet == NULL)
+		num_options = 0;
+	else {
+		for (i = 0; options[i].code; i++)
+			if (get_option(packet, options[i].code))
+				num_options++;
+		if (packet->siaddr) num_options++;
+		if ((temp = get_option(packet, DHCP_OPTION_OVER)))
+			over = *temp;
+		if (!(over & FILE_FIELD) && packet->file[0]) num_options++;
+		if (!(over & SNAME_FIELD) && packet->sname[0]) num_options++;		
+	}
+	
+	envp = xmalloc((num_options + 5) * sizeof(char *));
+	envp[0] = xmalloc(sizeof("interface=") + strlen(client_config.interface));
+	sprintf(envp[0], "interface=%s", client_config.interface);
+	envp[1] = find_env("PATH", "PATH=/bin:/usr/bin:/sbin:/usr/sbin");
+	envp[2] = find_env("HOME", "HOME=/");
+
+	if (packet == NULL) {
+		envp[3] = NULL;
+		return envp;
+	}
+
+	envp[3] = xmalloc(sizeof("ip=255.255.255.255"));
+	sprintip(envp[3], "ip=", (unsigned char *) &packet->yiaddr);
+	for (i = 0, j = 4; options[i].code; i++) {
+		if ((temp = get_option(packet, options[i].code))) {
+			envp[j] = xmalloc(max_option_length[(&options[i])->flags & TYPE_MASK] * (temp[OPT_LEN - 2] / option_lengths[(&options[i])->flags & TYPE_MASK]) + strlen((&options[i])->name) + 2);
+//			envp[j] = xmalloc(upper_length(temp[OPT_LEN - 2], &options[i]) + strlen(options[i].name) + 2);
+			fill_options(envp[j], temp, &options[i]);
+			j++;
+		}
+	}
+	if (packet->siaddr) {
+		envp[j] = xmalloc(sizeof("siaddr=255.255.255.255"));
+		sprintip(envp[j++], "siaddr=", (unsigned char *) &packet->yiaddr);
+	}
+	if (!(over & FILE_FIELD) && packet->file[0]) {
+		/* watch out for invalid packets */
+		packet->file[sizeof(packet->file) - 1] = '\0';
+		envp[j] = xmalloc(sizeof("boot_file=") + strlen(packet->file));
+		sprintf(envp[j++], "boot_file=%s", packet->file);
+	}
+	if (!(over & SNAME_FIELD) && packet->sname[0]) {
+		/* watch out for invalid packets */
+		packet->sname[sizeof(packet->sname) - 1] = '\0';
+		envp[j] = xmalloc(sizeof("sname=") + strlen(packet->sname));
+		sprintf(envp[j++], "sname=%s", packet->sname);
+	}	
+	envp[j] = NULL;
+	return envp;
+}
+
+/* Call a script with a par file and env vars */
+void run_script(struct dhcpMessage *packet, const char *name)
+{
+	int pid;
+	char **envp;
+
+	if (client_config.script == NULL)
+		return;
+
+	/* call script */
+	pid = fork();
+	if (pid) {
+		waitpid(pid, NULL, 0);
+		return;
+	} else if (pid == 0) {
+		envp = fill_envp(packet);
+		
+		/* close fd's? */
+		
+		/* exec script */
+		DEBUG(LOG_INFO, "execle'ing %s", client_config.script);
+		execle(client_config.script, client_config.script,
+		       name, NULL, envp);
+		LOG(LOG_ERR, "script %s failed: %s",
+		    client_config.script, sys_errlist[errno]);
+		exit(1);
+	}			
+}
+
+/* SIGUSR2 handler (release) */
+static void release_requested(int sig)
+{
+	sig = 0;
+	LOG(LOG_INFO, "Received SIGUSR2");
+	/* send release packet */
+	if (state == BOUND || state == RENEWING || state == REBINDING) {
+		struct dhcpMessage packet;
+
+		init_packet(&packet, DHCPRELEASE);
+		packet.xid = random_xid();
+		packet.ciaddr = requested_ip;
+	
+		add_simple_option(packet.options, DHCP_REQUESTED_IP, requested_ip);
+		add_simple_option(packet.options, DHCP_SERVER_ID, server_addr);
+
+		LOG(LOG_DEBUG, "Sending release...");
+		kernel_packet(&packet, requested_ip, CLIENT_PORT, server_addr, SERVER_PORT);
+		run_script(NULL, "deconfig");
+	}
+
+	change_mode(LISTEN_NONE);
+	state = RELEASED;
+	timeout = 0x7fffffff;
+}
+
+
+int pidfile_acquire(char *pidfile)
+{
+	int pid_fd;
+	if (pidfile == NULL) return -1;
+
+	pid_fd = open(pidfile, O_CREAT | O_WRONLY, 0644);
+	if (pid_fd < 0) {
+		LOG(LOG_ERR, "Unable to open pidfile %s: %s\n",
+		    pidfile, strerror(errno));
+	} else {
+		lockf(pid_fd, F_LOCK, 0);
+	}
+	
+	return pid_fd;
+}
+
+
+void pidfile_write_release(int pid_fd)
+{
+	FILE *out;
+
+	if (pid_fd < 0) return;
+
+	if ((out = fdopen(pid_fd, "w")) != NULL) {
+		fprintf(out, "%d\n", getpid());
+		fclose(out);
+	}
+	lockf(pid_fd, F_UNLCK, 0);
+	close(pid_fd);
+}
+
+
+void pidfile_delete(char *pidfile)
+{
+	if (pidfile) unlink(pidfile);
+}
+
+/* Exit and cleanup */
+static void exit_client(int retval)
+{
+	pidfile_delete(client_config.pidfile);
+	CLOSE_LOG();
+	exit(retval);
+}
+
+
+/* SIGTERM handler */
+static void terminate(int sig)
+{
+	sig = 0;
+	LOG(LOG_INFO, "Received SIGTERM");
+	exit_client(0);
+}
+
+
+static void background(void)
+{
+	int pid_fd;
+	if (client_config.quit_after_lease) {
+		exit_client(0);
+	} else if (!client_config.foreground) {
+		pid_fd = pidfile_acquire(client_config.pidfile); /* hold lock during fork. */
+		if (daemon(0, 0) == -1) {
+			perror("fork");
+			exit_client(1);
+		}
+		client_config.foreground = 1; /* Do not fork again. */
+		pidfile_write_release(pid_fd);
+	}
+}
+
+int read_interface(char *interface, int *ifindex, u_int32_t *addr, unsigned char *arp)
+{
+	int l_fd;
+	struct ifreq ifr;
+	struct sockaddr_in *s_in;
+
+	memset(&ifr, 0, sizeof(struct ifreq));
+	if((l_fd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) >= 0) {
+		ifr.ifr_addr.sa_family = AF_INET;
+		strcpy(ifr.ifr_name, interface);
+
+		if (addr) { 
+			if (ioctl(l_fd, SIOCGIFADDR, &ifr) == 0) {
+				s_in = (struct sockaddr_in *) &ifr.ifr_addr;
+				*addr = s_in->sin_addr.s_addr;
+				DEBUG(LOG_INFO, "%s (our ip) = %s", ifr.ifr_name, inet_ntoa(s_in->sin_addr));
+			} else {
+				LOG(LOG_ERR, "SIOCGIFADDR failed!: %s", sys_errlist[errno]);
+				return -1;
+			}
+		}
+		
+		if (ioctl(l_fd, SIOCGIFINDEX, &ifr) == 0) {
+			DEBUG(LOG_INFO, "adapter index %d", ifr.ifr_ifindex);
+			*ifindex = ifr.ifr_ifindex;
+		} else {
+			LOG(LOG_ERR, "SIOCGIFINDEX failed!: %s", sys_errlist[errno]);
+			return -1;
+		}
+		if (ioctl(l_fd, SIOCGIFHWADDR, &ifr) == 0) {
+			memcpy(arp, ifr.ifr_hwaddr.sa_data, 6);
+			DEBUG(LOG_INFO, "adapter hardware address %02x:%02x:%02x:%02x:%02x:%02x",
+				arp[0], arp[1], arp[2], arp[3], arp[4], arp[5]);
+		} else {
+			LOG(LOG_ERR, "SIOCGIFHWADDR failed!: %s", sys_errlist[errno]);
+			return -1;
+		}
+	} else {
+		LOG(LOG_ERR, "socket failed!: %s", sys_errlist[errno]);
+		return -1;
+	}
+	close(l_fd);
+	return 0;
+}
+
+
+int listen_socket(unsigned int ip, int port, char *inf)
+{
+	struct ifreq interface;
+	int l_fd;
+	struct sockaddr_in addr;
+	int n = 1;
+
+	DEBUG(LOG_INFO, "Opening listen socket on 0x%08x:%d %s\n", ip, port, inf);
+	if ((l_fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
+		DEBUG(LOG_ERR, "socket call failed: %s", sys_errlist[errno]);
+		return -1;
+	}
+	
+	memset(&addr, 0, sizeof(addr));
+	addr.sin_family = AF_INET;
+	addr.sin_port = htons(port);
+	addr.sin_addr.s_addr = ip;
+
+	if (setsockopt(l_fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) == -1) {
+		close(l_fd);
+		return -1;
+	}
+	if (setsockopt(l_fd, SOL_SOCKET, SO_BROADCAST, (char *) &n, sizeof(n)) == -1) {
+		close(l_fd);
+		return -1;
+	}
+
+	strncpy(interface.ifr_ifrn.ifrn_name, inf, IFNAMSIZ);
+	if (setsockopt(l_fd, SOL_SOCKET, SO_BINDTODEVICE,(char *)&interface, sizeof(interface)) < 0) {
+		close(l_fd);
+		return -1;
+	}
+
+	if (bind(l_fd, (struct sockaddr *)&addr, sizeof(struct sockaddr)) == -1) {
+		close(l_fd);
+		return -1;
+	}
+	
+	return l_fd;
+}
+
+
+int raw_socket(int ifindex)
+{
+	int l_fd;
+	struct sockaddr_ll sock;
+
+	DEBUG(LOG_INFO, "Opening raw socket on ifindex %d\n", ifindex);
+	if ((l_fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
+		DEBUG(LOG_ERR, "socket call failed: %s", sys_errlist[errno]);
+		return -1;
+	}
+	
+	sock.sll_family = AF_PACKET;
+	sock.sll_protocol = htons(ETH_P_IP);
+	sock.sll_ifindex = ifindex;
+	if (bind(l_fd, (struct sockaddr *) &sock, sizeof(sock)) < 0) {
+		DEBUG(LOG_ERR, "bind call failed: %s", sys_errlist[errno]);
+		close(l_fd);
+		return -1;
+	}
+
+	return l_fd;
+
+}
+
+/* read a packet from socket fd, return -1 on read error, -2 on packet error */
+int get_packet(struct dhcpMessage *packet, int l_fd)
+{
+	int bytes;
+	int i;
+	const char broken_vendors[][8] = {
+		"MSFT 98",
+		""
+	};
+	char unsigned *vendor;
+
+	memset(packet, 0, sizeof(struct dhcpMessage));
+	bytes = read(l_fd, packet, sizeof(struct dhcpMessage));
+	if (bytes < 0) {
+		DEBUG(LOG_INFO, "couldn't read on listening socket, ignoring");
+		return -1;
+	}
+
+	if (ntohl(packet->cookie) != DHCP_MAGIC) {
+		LOG(LOG_ERR, "received bogus message, ignoring");
+		return -2;
+	}
+	DEBUG(LOG_INFO, "Received a packet");
+	
+	if (packet->op == BOOTREQUEST && (vendor = get_option(packet, DHCP_VENDOR))) {
+		for (i = 0; broken_vendors[i][0]; i++) {
+			if (vendor[OPT_LEN - 2] == (unsigned char) strlen(broken_vendors[i]) &&
+			    !strncmp(vendor, broken_vendors[i], vendor[OPT_LEN - 2])) {
+			    	DEBUG(LOG_INFO, "broken client (%s), forcing broadcast",
+			    		broken_vendors[i]);
+			    	packet->flags |= htons(BROADCAST_FLAG);
+			}
+		}
+	}
+			    	
+
+	return bytes;
+}
+
+int get_raw_packet(struct dhcpMessage *payload, int l_fd)
+{
+	int bytes;
+	struct udp_dhcp_packet packet;
+	u_int32_t source, dest;
+	u_int16_t check;
+
+	memset(&packet, 0, sizeof(struct udp_dhcp_packet));
+	bytes = read(l_fd, &packet, sizeof(struct udp_dhcp_packet));
+	if (bytes < 0) {
+		DEBUG(LOG_INFO, "couldn't read on raw listening socket -- ignoring");
+		usleep(500000); /* possible down interface, looping condition */
+		return -1;
+	}
+	
+	if (bytes < (int) (sizeof(struct iphdr) + sizeof(struct udphdr))) {
+		DEBUG(LOG_INFO, "message too short, ignoring");
+		return -1;
+	}
+	
+	if (bytes < ntohs(packet.ip.tot_len)) {
+		DEBUG(LOG_INFO, "Truncated packet");
+		return -1;
+	}
+	
+	/* ignore any extra garbage bytes */
+	bytes = ntohs(packet.ip.tot_len);
+	
+	/* Make sure its the right packet for us, and that it passes sanity checks */
+	if (packet.ip.protocol != IPPROTO_UDP || packet.ip.version != IPVERSION ||
+	    packet.ip.ihl != sizeof(packet.ip) >> 2 || packet.udp.dest != htons(CLIENT_PORT) ||
+	    bytes > (int) sizeof(struct udp_dhcp_packet) ||
+	    ntohs(packet.udp.len) != (short) (bytes - sizeof(packet.ip))) {
+	    	DEBUG(LOG_INFO, "unrelated/bogus packet");
+	    	return -1;
+	}
+
+	/* check IP checksum */
+	check = packet.ip.check;
+	packet.ip.check = 0;
+	if (check != checksum(&(packet.ip), sizeof(packet.ip))) {
+		DEBUG(LOG_INFO, "bad IP header checksum, ignoring");
+		return -1;
+	}
+	
+	/* verify the UDP checksum by replacing the header with a psuedo header */
+	source = packet.ip.saddr;
+	dest = packet.ip.daddr;
+	check = packet.udp.check;
+	packet.udp.check = 0;
+	memset(&packet.ip, 0, sizeof(packet.ip));
+
+	packet.ip.protocol = IPPROTO_UDP;
+	packet.ip.saddr = source;
+	packet.ip.daddr = dest;
+	packet.ip.tot_len = packet.udp.len; /* cheat on the psuedo-header */
+	if (check && check != checksum(&packet, bytes)) {
+		DEBUG(LOG_ERR, "packet with bad UDP checksum received, ignoring");
+		return -1;
+	}
+	
+	memcpy(payload, &(packet.data), bytes - (sizeof(packet.ip) + sizeof(packet.udp)));
+	
+	if (ntohl(payload->cookie) != DHCP_MAGIC) {
+		LOG(LOG_ERR, "received bogus message (bad magic) -- ignoring");
+		return -1;
+	}
+	DEBUG(LOG_INFO, "oooooh!!! got some!");
+	return bytes - (sizeof(packet.ip) + sizeof(packet.udp));
+	
+}
+
+
+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;
+	int pid_fd;
+	time_t now;
+
+	static struct option l_options[] = {
+		{"clientid",	required_argument,	0, 'c'},
+		{"foreground",	no_argument,		0, 'f'},
+		{"hostname",	required_argument,	0, 'H'},
+		{"help",	no_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:fH:hi:np:qr:s:v", l_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 + 3, optarg, len - 1);
+			break;
+		case 'f':
+			client_config.foreground = 1;
+			break;
+		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 'h':
+			print_usage();
+			return 0;
+		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':
+			printf("udhcpcd, version %s\n\n", VERSION);
+			exit_client(0);
+			break;
+		}
+	}
+
+	OPEN_LOG("udhcpc");
+	LOG(LOG_INFO, "udhcp client (v%s) started", VERSION);
+
+	pid_fd = pidfile_acquire(client_config.pidfile);
+	pidfile_write_release(pid_fd);
+
+	if (read_interface(client_config.interface, &client_config.ifindex, NULL, client_config.arp) < 0) {
+		exit_client(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 */
+	signal(SIGUSR1, renew_requested);
+	signal(SIGUSR2, release_requested);
+	signal(SIGTERM, terminate);
+	
+	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_main < 0) {
+			if (listen_mode == LISTEN_KERNEL) {
+				fd_main = listen_socket(INADDR_ANY, CLIENT_PORT, client_config.interface);
+			} else {
+				fd_main = raw_socket(client_config.ifindex);
+			}
+			if (fd_main < 0) {
+				LOG(LOG_ERR, "FATAL: couldn't listen on socket, %s", sys_errlist[errno]);
+				exit_client(0);
+			}
+		}
+		if (fd_main >= 0) {
+			FD_SET(fd_main, &rfds);
+		}
+
+		if (tv.tv_sec > 0) {
+			DEBUG(LOG_INFO, "Waiting on select...\n");
+			retval = select(fd_main + 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) ? 10 : 2);
+					packet_num++;
+				} else {
+					if (client_config.abort_if_no_lease) {
+						LOG(LOG_INFO, "No lease, failing.");
+						exit_client(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 */
+					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_main, &rfds)) {
+			/* a packet is ready, read it */
+			
+			if (listen_mode == LISTEN_KERNEL) {
+				len = get_packet(&packet, fd_main);
+			} else {
+				len = get_raw_packet(&packet, fd_main);
+			}
+			if (len == -1 && errno != EINTR) {
+				DEBUG(LOG_INFO, "error on read, %s, reopening socket", sys_errlist[errno]);
+				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);
+					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 == -1 && errno == EINTR) {
+			/* a signal was caught */
+			
+		} else {
+			/* An error occured */
+			DEBUG(LOG_ERR, "Error on select");
+		}
+		
+	}
+	return 0;
+}