262 lines
7.1 KiB
C
262 lines
7.1 KiB
C
/* dhcpd.c
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*
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* udhcp Server
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* Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au>
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* Chris Trew <ctrew@moreton.com.au>
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*
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* Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <fcntl.h>
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#include <string.h>
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#include <stdlib.h>
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#include <sys/wait.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include <signal.h>
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#include <errno.h>
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#include <sys/ioctl.h>
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#include <time.h>
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#include <sys/time.h>
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#include "dhcpd.h"
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#include "arpping.h"
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#include "socket.h"
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#include "options.h"
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#include "files.h"
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#include "serverpacket.h"
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#include "common.h"
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#include "signalpipe.h"
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#include "static_leases.h"
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/* globals */
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struct dhcpOfferedAddr *leases;
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struct server_config_t server_config;
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int udhcpd_main(int argc, char *argv[])
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{
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fd_set rfds;
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struct timeval tv;
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int server_socket = -1, bytes, retval, max_sock;
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struct dhcpMessage packet;
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uint8_t *state, *server_id, *requested;
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uint32_t server_id_align, requested_align, static_lease_ip;
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unsigned long timeout_end, num_ips;
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struct option_set *option;
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struct dhcpOfferedAddr *lease, static_lease;
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read_config(argc < 2 ? DHCPD_CONF_FILE : argv[1]);
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/* Start the log, sanitize fd's, and write a pid file */
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start_log_and_pid("udhcpd", server_config.pidfile);
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if ((option = find_option(server_config.options, DHCP_LEASE_TIME))) {
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memcpy(&server_config.lease, option->data + 2, 4);
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server_config.lease = ntohl(server_config.lease);
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}
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else server_config.lease = LEASE_TIME;
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/* Sanity check */
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num_ips = ntohl(server_config.end) - ntohl(server_config.start) + 1;
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if (server_config.max_leases > num_ips) {
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LOG(LOG_ERR, "max_leases value (%lu) not sane, "
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"setting to %lu instead",
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server_config.max_leases, num_ips);
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server_config.max_leases = num_ips;
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}
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leases = xzalloc(server_config.max_leases * sizeof(struct dhcpOfferedAddr));
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read_leases(server_config.lease_file);
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if (read_interface(server_config.interface, &server_config.ifindex,
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&server_config.server, server_config.arp) < 0)
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return 1;
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#ifndef UDHCP_DEBUG
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background(server_config.pidfile); /* hold lock during fork. */
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#endif
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/* Setup the signal pipe */
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udhcp_sp_setup();
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timeout_end = time(0) + server_config.auto_time;
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while(1) { /* loop until universe collapses */
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if (server_socket < 0)
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if ((server_socket = listen_socket(INADDR_ANY, SERVER_PORT, server_config.interface)) < 0) {
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LOG(LOG_ERR, "FATAL: couldn't create server socket, %m");
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return 2;
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}
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max_sock = udhcp_sp_fd_set(&rfds, server_socket);
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if (server_config.auto_time) {
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tv.tv_sec = timeout_end - time(0);
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tv.tv_usec = 0;
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}
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if (!server_config.auto_time || tv.tv_sec > 0) {
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retval = select(max_sock + 1, &rfds, NULL, NULL,
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server_config.auto_time ? &tv : NULL);
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} else retval = 0; /* If we already timed out, fall through */
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if (retval == 0) {
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write_leases();
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timeout_end = time(0) + server_config.auto_time;
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continue;
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} else if (retval < 0 && errno != EINTR) {
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DEBUG(LOG_INFO, "error on select");
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continue;
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}
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switch (udhcp_sp_read(&rfds)) {
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case SIGUSR1:
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LOG(LOG_INFO, "Received a SIGUSR1");
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write_leases();
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/* why not just reset the timeout, eh */
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timeout_end = time(0) + server_config.auto_time;
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continue;
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case SIGTERM:
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LOG(LOG_INFO, "Received a SIGTERM");
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return 0;
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case 0: break; /* no signal */
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default: continue; /* signal or error (probably EINTR) */
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}
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if ((bytes = get_packet(&packet, server_socket)) < 0) { /* this waits for a packet - idle */
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if (bytes == -1 && errno != EINTR) {
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DEBUG(LOG_INFO, "error on read, %m, reopening socket");
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close(server_socket);
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server_socket = -1;
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}
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continue;
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}
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if ((state = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
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DEBUG(LOG_ERR, "couldn't get option from packet, ignoring");
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continue;
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}
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/* Look for a static lease */
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static_lease_ip = getIpByMac(server_config.static_leases, &packet.chaddr);
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if(static_lease_ip)
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{
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printf("Found static lease: %x\n", static_lease_ip);
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memcpy(&static_lease.chaddr, &packet.chaddr, 16);
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static_lease.yiaddr = static_lease_ip;
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static_lease.expires = 0;
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lease = &static_lease;
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}
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else
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{
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lease = find_lease_by_chaddr(packet.chaddr);
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}
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switch (state[0]) {
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case DHCPDISCOVER:
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DEBUG(LOG_INFO,"received DISCOVER");
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if (sendOffer(&packet) < 0) {
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LOG(LOG_ERR, "send OFFER failed");
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}
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break;
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case DHCPREQUEST:
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DEBUG(LOG_INFO, "received REQUEST");
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requested = get_option(&packet, DHCP_REQUESTED_IP);
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server_id = get_option(&packet, DHCP_SERVER_ID);
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if (requested) memcpy(&requested_align, requested, 4);
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if (server_id) memcpy(&server_id_align, server_id, 4);
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if (lease) {
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if (server_id) {
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/* SELECTING State */
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DEBUG(LOG_INFO, "server_id = %08x", ntohl(server_id_align));
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if (server_id_align == server_config.server && requested &&
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requested_align == lease->yiaddr) {
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sendACK(&packet, lease->yiaddr);
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}
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} else {
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if (requested) {
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/* INIT-REBOOT State */
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if (lease->yiaddr == requested_align)
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sendACK(&packet, lease->yiaddr);
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else sendNAK(&packet);
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} else {
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/* RENEWING or REBINDING State */
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if (lease->yiaddr == packet.ciaddr)
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sendACK(&packet, lease->yiaddr);
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else {
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/* don't know what to do!!!! */
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sendNAK(&packet);
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}
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}
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}
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/* what to do if we have no record of the client */
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} else if (server_id) {
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/* SELECTING State */
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} else if (requested) {
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/* INIT-REBOOT State */
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if ((lease = find_lease_by_yiaddr(requested_align))) {
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if (lease_expired(lease)) {
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/* probably best if we drop this lease */
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memset(lease->chaddr, 0, 16);
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/* make some contention for this address */
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} else sendNAK(&packet);
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} else if (requested_align < server_config.start ||
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requested_align > server_config.end) {
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sendNAK(&packet);
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} /* else remain silent */
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} else {
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/* RENEWING or REBINDING State */
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}
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break;
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case DHCPDECLINE:
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DEBUG(LOG_INFO,"received DECLINE");
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if (lease) {
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memset(lease->chaddr, 0, 16);
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lease->expires = time(0) + server_config.decline_time;
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}
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break;
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case DHCPRELEASE:
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DEBUG(LOG_INFO,"received RELEASE");
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if (lease) lease->expires = time(0);
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break;
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case DHCPINFORM:
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DEBUG(LOG_INFO,"received INFORM");
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send_inform(&packet);
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break;
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default:
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LOG(LOG_WARNING, "unsupported DHCP message (%02x) -- ignoring", state[0]);
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}
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}
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return 0;
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}
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