/* 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;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 2static int listen_mode;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,	.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(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 */		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;		LOG(LOG_INFO, "Unicasting a release of %s to %s",				inet_ntoa(temp_addr), buffer);		send_release(server_addr, requested_ip); /* unicast */		udhcp_run_script(NULL, "deconfig");	}	LOG(LOG_INFO, "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;	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'},		{"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:qr: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':			requested_ip = inet_addr(optarg);			break;		case 's':			client_config.script = optarg;			break;		case 'T':			client_config.timeout = atoi(optarg);			break;		case 't':			client_config.retries = atoi(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("udhcpc", 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) {				LOG(LOG_ERR, "FATAL: couldn't listen on socket, %m");				return 0;			}		}		max_fd = udhcp_sp_fd_set(&rfds, fd);		if (tv.tv_sec > 0) {			DEBUG(LOG_INFO, "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) {						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 < 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(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");					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(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;			}			/* Ignore packets that aren't for us */			if (memcmp(packet.chaddr, client_config.arp, 6)) {				DEBUG(LOG_INFO, "packet does not have our chaddr -- ignoring");				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;					udhcp_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");					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:				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;}