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|
/* 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;
}
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