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

 /* dhcpd.c
  *
  * udhcp Server
  * Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au>
  *			Chris Trew <ctrew@moreton.com.au>
  *
  * Rewrite by 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 <fcntl.h>
 #include <string.h>
 #include <stdlib.h>
 #include <sys/wait.h>
 #include <arpa/inet.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <sys/socket.h>
 #include <unistd.h>
 #include <signal.h>
 #include <errno.h>
 #include <sys/ioctl.h>
 #include <time.h>
 #include <sys/time.h>

 #include "dhcpd.h"
 #include "arpping.h"
 #include "socket.h"
 #include "options.h"
 #include "files.h"
 #include "serverpacket.h"
 #include "common.h"
 #include "signalpipe.h"


 /* globals */
 struct dhcpOfferedAddr *leases;
 struct server_config_t server_config;


 #ifdef COMBINED_BINARY
 int udhcpd_main(int argc, char *argv[])
 #else
 int main(int argc, char *argv[])
 #endif
 {
 	fd_set rfds;
 	struct timeval tv;
 	int server_socket = -1;
 	int bytes, retval;
 	struct dhcpMessage packet;
 	uint8_t *state;
 	uint8_t *server_id, *requested;
 	uint32_t server_id_align, requested_align;
 	unsigned long timeout_end;
 	struct option_set *option;
 	struct dhcpOfferedAddr *lease;
 	int max_sock;
 	unsigned long num_ips;

 	memset(&server_config, 0, sizeof(struct server_config_t));
 	read_config(argc < 2 ? DHCPD_CONF_FILE : argv[1]);

 	/* Start the log, sanitize fd's, and write a pid file */
 	start_log_and_pid("udhcpd", server_config.pidfile);

 	if ((option = find_option(server_config.options, DHCP_LEASE_TIME))) {
 		memcpy(&server_config.lease, option->data + 2, 4);
 		server_config.lease = ntohl(server_config.lease);
 	}
 	else server_config.lease = LEASE_TIME;

 	/* Sanity check */
 	num_ips = ntohl(server_config.end) - ntohl(server_config.start);
 	if (server_config.max_leases > num_ips) {
 		LOG(LOG_ERR, "max_leases value (%lu) not sane, "
 			"setting to %lu instead",
 			server_config.max_leases, num_ips);
 		server_config.max_leases = num_ips;
 	}

 	leases = xcalloc(server_config.max_leases, sizeof(struct dhcpOfferedAddr));
 	read_leases(server_config.lease_file);

 	if (read_interface(server_config.interface, &server_config.ifindex,
 			   &server_config.server, server_config.arp) < 0)
 		return 1;

 #ifndef UDHCP_DEBUG
 	background(server_config.pidfile); /* hold lock during fork. */
 #endif

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

 	timeout_end = time(0) + server_config.auto_time;
 	while(1) { /* loop until universe collapses */

 		if (server_socket < 0)
 			if ((server_socket = listen_socket(INADDR_ANY, SERVER_PORT, server_config.interface)) < 0) {
 				LOG(LOG_ERR, "FATAL: couldn't create server socket, %m");
 				return 2;
 			}

 		max_sock = udhcp_sp_fd_set(&rfds, server_socket);
 		if (server_config.auto_time) {
 			tv.tv_sec = timeout_end - time(0);
 			tv.tv_usec = 0;
 		}
 		if (!server_config.auto_time || tv.tv_sec > 0) {
 			retval = select(max_sock + 1, &rfds, NULL, NULL,
 					server_config.auto_time ? &tv : NULL);
 		} else retval = 0; /* If we already timed out, fall through */

 		if (retval == 0) {
 			write_leases();
 			timeout_end = time(0) + server_config.auto_time;
 			continue;
 		} else if (retval < 0 && errno != EINTR) {
 			DEBUG(LOG_INFO, "error on select");
 			continue;
 		}

 		switch (udhcp_sp_read(&rfds)) {
 		case SIGUSR1:
 			LOG(LOG_INFO, "Received a SIGUSR1");
 			write_leases();
 			/* why not just reset the timeout, eh */
 			timeout_end = time(0) + server_config.auto_time;
 			continue;
 		case SIGTERM:
 			LOG(LOG_INFO, "Received a SIGTERM");
 			return 0;
 		case 0: break;		/* no signal */
 		default: continue;	/* signal or error (probably EINTR) */
 		}

 		if ((bytes = get_packet(&packet, server_socket)) < 0) { /* this waits for a packet - idle */
 			if (bytes == -1 && errno != EINTR) {
 				DEBUG(LOG_INFO, "error on read, %m, reopening socket");
 				close(server_socket);
 				server_socket = -1;
 			}
 			continue;
 		}

 		if ((state = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
 			DEBUG(LOG_ERR, "couldn't get option from packet, ignoring");
 			continue;
 		}

 		/* ADDME: look for a static lease */
 		lease = find_lease_by_chaddr(packet.chaddr);
 		switch (state[0]) {
 		case DHCPDISCOVER:
 			DEBUG(LOG_INFO,"received DISCOVER");

 			if (sendOffer(&packet) < 0) {
 				LOG(LOG_ERR, "send OFFER failed");
 			}
 			break;
  		case DHCPREQUEST:
 			DEBUG(LOG_INFO, "received REQUEST");

 			requested = get_option(&packet, DHCP_REQUESTED_IP);
 			server_id = get_option(&packet, DHCP_SERVER_ID);

 			if (requested) memcpy(&requested_align, requested, 4);
 			if (server_id) memcpy(&server_id_align, server_id, 4);

 			if (lease) { /*ADDME: or static lease */
 				if (server_id) {
 					/* SELECTING State */
 					DEBUG(LOG_INFO, "server_id = %08x", ntohl(server_id_align));
 					if (server_id_align == server_config.server && requested &&
 					    requested_align == lease->yiaddr) {
 						sendACK(&packet, lease->yiaddr);
 					}
 				} else {
 					if (requested) {
 						/* INIT-REBOOT State */
 						if (lease->yiaddr == requested_align)
 							sendACK(&packet, lease->yiaddr);
 						else sendNAK(&packet);
 					} else {
 						/* RENEWING or REBINDING State */
 						if (lease->yiaddr == packet.ciaddr)
 							sendACK(&packet, lease->yiaddr);
 						else {
 							/* don't know what to do!!!! */
 							sendNAK(&packet);
 						}
 					}
 				}

 			/* what to do if we have no record of the client */
 			} else if (server_id) {
 				/* SELECTING State */

 			} else if (requested) {
 				/* INIT-REBOOT State */
 				if ((lease = find_lease_by_yiaddr(requested_align))) {
 					if (lease_expired(lease)) {
 						/* probably best if we drop this lease */
 						memset(lease->chaddr, 0, 16);
 					/* make some contention for this address */
 					} else sendNAK(&packet);
 				} else if (requested_align < server_config.start ||
 					   requested_align > server_config.end) {
 					sendNAK(&packet);
 				} /* else remain silent */

 			} else {
 				 /* RENEWING or REBINDING State */
 			}
 			break;
 		case DHCPDECLINE:
 			DEBUG(LOG_INFO,"received DECLINE");
 			if (lease) {
 				memset(lease->chaddr, 0, 16);
 				lease->expires = time(0) + server_config.decline_time;
 			}
 			break;
 		case DHCPRELEASE:
 			DEBUG(LOG_INFO,"received RELEASE");
 			if (lease) lease->expires = time(0);
 			break;
 		case DHCPINFORM:
 			DEBUG(LOG_INFO,"received INFORM");
 			send_inform(&packet);
 			break;
 		default:
 			LOG(LOG_WARNING, "unsupported DHCP message (%02x) -- ignoring", state[0]);
 		}
 	}

 	return 0;
 }
	/* dhcpd.c
	*
	* udhcp Server
	* Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au>
	* Chris Trew <ctrew@moreton.com.au>
	*
	* Rewrite by 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 <fcntl.h>
	#include <string.h>
	#include <stdlib.h>
	#include <sys/wait.h>
	#include <arpa/inet.h>
	#include <netdb.h>
	#include <netinet/in.h>
	#include <sys/socket.h>
	#include <unistd.h>
	#include <signal.h>
	#include <errno.h>
	#include <sys/ioctl.h>
	#include <time.h>
	#include <sys/time.h>

	#include "dhcpd.h"
	#include "arpping.h"
	#include "socket.h"
	#include "options.h"
	#include "files.h"
	#include "serverpacket.h"
	#include "common.h"
	#include "signalpipe.h"


	/* globals */
	struct dhcpOfferedAddr *leases;
	struct server_config_t server_config;


	#ifdef COMBINED_BINARY
	int udhcpd_main(int argc, char *argv[])
	#else
	int main(int argc, char *argv[])
	#endif
	{
	fd_set rfds;
	struct timeval tv;
	int server_socket = -1;
	int bytes, retval;
	struct dhcpMessage packet;
	uint8_t *state;
	uint8_t server_id, requested;
	uint32_t server_id_align, requested_align;
	unsigned long timeout_end;
	struct option_set *option;
	struct dhcpOfferedAddr *lease;
	int max_sock;
	unsigned long num_ips;

	memset(&server_config, 0, sizeof(struct server_config_t));
	read_config(argc < 2 ? DHCPD_CONF_FILE : argv[1]);

	/* Start the log, sanitize fd's, and write a pid file */
	start_log_and_pid("udhcpd", server_config.pidfile);

	if ((option = find_option(server_config.options, DHCP_LEASE_TIME))) {
	memcpy(&server_config.lease, option->data + 2, 4);
	server_config.lease = ntohl(server_config.lease);
	}
	else server_config.lease = LEASE_TIME;

	/* Sanity check */
	num_ips = ntohl(server_config.end) - ntohl(server_config.start);
	if (server_config.max_leases > num_ips) {
	LOG(LOG_ERR, "max_leases value (%lu) not sane, "
	"setting to %lu instead",
	server_config.max_leases, num_ips);
	server_config.max_leases = num_ips;
	}

	leases = xcalloc(server_config.max_leases, sizeof(struct dhcpOfferedAddr));
	read_leases(server_config.lease_file);

	if (read_interface(server_config.interface, &server_config.ifindex,
	&server_config.server, server_config.arp) < 0)
	return 1;

	#ifndef UDHCP_DEBUG
	background(server_config.pidfile); /* hold lock during fork. */
	#endif

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

	timeout_end = time(0) + server_config.auto_time;
	while(1) { /* loop until universe collapses */

	if (server_socket < 0)
	if ((server_socket = listen_socket(INADDR_ANY, SERVER_PORT, server_config.interface)) < 0) {
	LOG(LOG_ERR, "FATAL: couldn't create server socket, %m");
	return 2;
	}

	max_sock = udhcp_sp_fd_set(&rfds, server_socket);
	if (server_config.auto_time) {
	tv.tv_sec = timeout_end - time(0);
	tv.tv_usec = 0;
	}
	if (!server_config.auto_time \|\| tv.tv_sec > 0) {
	retval = select(max_sock + 1, &rfds, NULL, NULL,
	server_config.auto_time ? &tv : NULL);
	} else retval = 0; /* If we already timed out, fall through */

	if (retval == 0) {
	write_leases();
	timeout_end = time(0) + server_config.auto_time;
	continue;
	} else if (retval < 0 && errno != EINTR) {
	DEBUG(LOG_INFO, "error on select");
	continue;
	}

	switch (udhcp_sp_read(&rfds)) {
	case SIGUSR1:
	LOG(LOG_INFO, "Received a SIGUSR1");
	write_leases();
	/* why not just reset the timeout, eh */
	timeout_end = time(0) + server_config.auto_time;
	continue;
	case SIGTERM:
	LOG(LOG_INFO, "Received a SIGTERM");
	return 0;
	case 0: break; /* no signal */
	default: continue; /* signal or error (probably EINTR) */
	}

	if ((bytes = get_packet(&packet, server_socket)) < 0) { /* this waits for a packet - idle */
	if (bytes == -1 && errno != EINTR) {
	DEBUG(LOG_INFO, "error on read, %m, reopening socket");
	close(server_socket);
	server_socket = -1;
	}
	continue;
	}

	if ((state = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
	DEBUG(LOG_ERR, "couldn't get option from packet, ignoring");
	continue;
	}

	/* ADDME: look for a static lease */
	lease = find_lease_by_chaddr(packet.chaddr);
	switch (state[0]) {
	case DHCPDISCOVER:
	DEBUG(LOG_INFO,"received DISCOVER");

	if (sendOffer(&packet) < 0) {
	LOG(LOG_ERR, "send OFFER failed");
	}
	break;
	case DHCPREQUEST:
	DEBUG(LOG_INFO, "received REQUEST");

	requested = get_option(&packet, DHCP_REQUESTED_IP);
	server_id = get_option(&packet, DHCP_SERVER_ID);

	if (requested) memcpy(&requested_align, requested, 4);
	if (server_id) memcpy(&server_id_align, server_id, 4);

	if (lease) { /ADDME: or static lease /
	if (server_id) {
	/* SELECTING State */
	DEBUG(LOG_INFO, "server_id = %08x", ntohl(server_id_align));
	if (server_id_align == server_config.server && requested &&
	requested_align == lease->yiaddr) {
	sendACK(&packet, lease->yiaddr);
	}
	} else {
	if (requested) {
	/* INIT-REBOOT State */
	if (lease->yiaddr == requested_align)
	sendACK(&packet, lease->yiaddr);
	else sendNAK(&packet);
	} else {
	/* RENEWING or REBINDING State */
	if (lease->yiaddr == packet.ciaddr)
	sendACK(&packet, lease->yiaddr);
	else {
	/* don't know what to do!!!! */
	sendNAK(&packet);
	}
	}
	}

	/* what to do if we have no record of the client */
	} else if (server_id) {
	/* SELECTING State */

	} else if (requested) {
	/* INIT-REBOOT State */
	if ((lease = find_lease_by_yiaddr(requested_align))) {
	if (lease_expired(lease)) {
	/* probably best if we drop this lease */
	memset(lease->chaddr, 0, 16);
	/* make some contention for this address */
	} else sendNAK(&packet);
	} else if (requested_align < server_config.start \|\|
	requested_align > server_config.end) {
	sendNAK(&packet);
	} /* else remain silent */

	} else {
	/* RENEWING or REBINDING State */
	}
	break;
	case DHCPDECLINE:
	DEBUG(LOG_INFO,"received DECLINE");
	if (lease) {
	memset(lease->chaddr, 0, 16);
	lease->expires = time(0) + server_config.decline_time;
	}
	break;
	case DHCPRELEASE:
	DEBUG(LOG_INFO,"received RELEASE");
	if (lease) lease->expires = time(0);
	break;
	case DHCPINFORM:
	DEBUG(LOG_INFO,"received INFORM");
	send_inform(&packet);
	break;
	default:
	LOG(LOG_WARNING, "unsupported DHCP message (%02x) -- ignoring", state[0]);
	}
	}

	return 0;
	}