1/* dhcpd.c
2 *
3 * udhcp Server
4 * Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au>
5 *			Chris Trew <ctrew@moreton.com.au>
6 *
7 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 */
23
24#include <fcntl.h>
25#include <string.h>
26#include <stdlib.h>
27#include <sys/wait.h>
28#include <sys/stat.h>
29#include <arpa/inet.h>
30#include <netdb.h>
31#include <netinet/in.h>
32#include <stdio.h>
33#include <sys/types.h>
34#include <sys/socket.h>
35#include <unistd.h>
36#include <signal.h>
37#include <errno.h>
38#include <sys/ioctl.h>
39#include <time.h>
40#include <sys/time.h>
41
42#include "debug.h"
43#include "dhcpd.h"
44#include "arpping.h"
45#include "socket.h"
46#include "options.h"
47#include "files.h"
48#include "leases.h"
49#include "packet.h"
50#include "serverpacket.h"
51#include "pidfile.h"
52
53extern void load_leases(char *file);
54
55/* globals */
56struct dhcpOfferedAddr *leases;
57struct server_config_t server_config;
58static int signal_pipe[2];
59
60/* Exit and cleanup */
61static void exit_server(int retval)
62{
63	pidfile_delete(server_config.pidfile);
64	CLOSE_LOG();
65	exit(retval);
66}
67
68
69/* Signal handler */
70static void signal_handler(int sig)
71{
72	if (send(signal_pipe[1], &sig, sizeof(sig), MSG_DONTWAIT) < 0) {
73		LOG(LOG_ERR, "Could not send signal: %s",
74			strerror(errno));
75	}
76}
77
78
79#ifdef COMBINED_BINARY
80int udhcpd_main(int argc, char *argv[])
81#else
82int main(int argc, char *argv[])
83#endif
84{
85	fd_set rfds;
86	struct timeval tv;
87	int server_socket = -1;
88	int bytes, retval;
89	struct dhcpMessage packet;
90	unsigned char *state;
91	unsigned char *server_id, *requested, *hostname;
92	u_int32_t server_id_align, requested_align;
93	unsigned long timeout_end;
94	struct option_set *option;
95	struct dhcpOfferedAddr *lease;
96	int pid_fd;
97	int max_sock;
98	int sig;
99
100	OPEN_LOG("udhcpd");
101	LOG(LOG_INFO, "udhcp server (v%s) started", VERSION);
102
103	memset(&server_config, 0, sizeof(struct server_config_t));
104
105	if (argc < 2)
106		read_config(DHCPD_CONF_FILE);
107	else read_config(argv[1]);
108
109	pid_fd = pidfile_acquire(server_config.pidfile);
110	pidfile_write_release(pid_fd);
111
112	if ((option = find_option(server_config.options, DHCP_LEASE_TIME))) {
113		memcpy(&server_config.lease, option->data + 2, 4);
114		server_config.lease = ntohl(server_config.lease);
115	}
116	else server_config.lease = LEASE_TIME;
117
118	leases = malloc(sizeof(struct dhcpOfferedAddr) * server_config.max_leases);
119	memset(leases, 0, sizeof(struct dhcpOfferedAddr) * server_config.max_leases);
120
121	// Added by Joey to load static lease
122	if (argc>=3)
123	{
124		load_leases(argv[2]);
125	}
126
127	read_leases(server_config.lease_file);
128
129	if (read_interface(server_config.interface, &server_config.ifindex,
130			   &server_config.server, server_config.arp) < 0)
131		exit_server(1);
132
133#ifndef DEBUGGING
134	pid_fd = pidfile_acquire(server_config.pidfile); /* hold lock during fork. */
135	if (daemon(0, 0) == -1) {
136		perror("fork");
137		exit_server(1);
138	}
139	pidfile_write_release(pid_fd);
140#endif
141
142
143	socketpair(AF_UNIX, SOCK_STREAM, 0, signal_pipe);
144	signal(SIGUSR1, signal_handler);
145	signal(SIGTERM, signal_handler);
146
147	timeout_end = time(0) + server_config.auto_time;
148	while(1) { /* loop until universe collapses */
149
150		if (server_socket < 0)
151			if ((server_socket = listen_socket(INADDR_ANY, SERVER_PORT, server_config.interface)) < 0) {
152				LOG(LOG_ERR, "FATAL: couldn't create server socket, %s", strerror(errno));
153				exit_server(0);
154			}
155
156		FD_ZERO(&rfds);
157		FD_SET(server_socket, &rfds);
158		FD_SET(signal_pipe[0], &rfds);
159		if (server_config.auto_time) {
160			tv.tv_sec = timeout_end - time(0);
161			tv.tv_usec = 0;
162		}
163		if (!server_config.auto_time || tv.tv_sec > 0) {
164			max_sock = server_socket > signal_pipe[0] ? server_socket : signal_pipe[0];
165			retval = select(max_sock + 1, &rfds, NULL, NULL,
166					server_config.auto_time ? &tv : NULL);
167		} else retval = 0; /* If we already timed out, fall through */
168
169		if (retval == 0) {
170			write_leases();
171			timeout_end = time(0) + server_config.auto_time;
172			continue;
173		} else if (retval < 0 && errno != EINTR) {
174			DEBUG(LOG_INFO, "error on select");
175			continue;
176		}
177
178		if (FD_ISSET(signal_pipe[0], &rfds)) {
179			if (read(signal_pipe[0], &sig, sizeof(sig)) < 0)
180				continue; /* probably just EINTR */
181			switch (sig) {
182			case SIGUSR1:
183				LOG(LOG_INFO, "Received a SIGUSR1");
184				write_leases();
185				/* why not just reset the timeout, eh */
186				timeout_end = time(0) + server_config.auto_time;
187				continue;
188			case SIGTERM:
189				LOG(LOG_INFO, "Received a SIGTERM");
190				exit_server(0);
191			}
192		}
193
194		if ((bytes = get_packet(&packet, server_socket)) < 0) { /* this waits for a packet - idle */
195			if (bytes == -1 && errno != EINTR) {
196				DEBUG(LOG_INFO, "error on read, %s, reopening socket", strerror(errno));
197				close(server_socket);
198				server_socket = -1;
199			}
200			continue;
201		}
202
203		if ((state = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
204			DEBUG(LOG_ERR, "couldn't get option from packet, ignoring");
205			continue;
206		}
207
208		/* ADDME: look for a static lease */
209		lease = find_lease_by_chaddr(packet.chaddr);
210		switch (state[0]) {
211		case DHCPDISCOVER:
212			DEBUG(LOG_INFO,"received DISCOVER");
213
214			if (sendOffer(&packet) < 0) {
215				LOG(LOG_ERR, "send OFFER failed");
216			}
217			break;
218 		case DHCPREQUEST:
219			DEBUG(LOG_INFO, "received REQUEST");
220
221			requested = get_option(&packet, DHCP_REQUESTED_IP);
222			server_id = get_option(&packet, DHCP_SERVER_ID);
223			hostname = get_option(&packet, DHCP_HOST_NAME);
224
225			if (requested) memcpy(&requested_align, requested, 4);
226			if (server_id) memcpy(&server_id_align, server_id, 4);
227
228			if (lease) { /*ADDME: or static lease */
229				if (server_id) {
230					/* SELECTING State */
231					DEBUG(LOG_INFO, "server_id = %08x", ntohl(server_id_align));
232					if (server_id_align == server_config.server && requested &&
233					    requested_align == lease->yiaddr) {
234						sendACK(&packet, lease->yiaddr);
235					}
236				} else {
237					if (requested) {
238						/* INIT-REBOOT State */
239						if (lease->yiaddr == requested_align)
240							sendACK(&packet, lease->yiaddr);
241						else sendNAK(&packet);
242					} else {
243						/* RENEWING or REBINDING State */
244						if (lease->yiaddr == packet.ciaddr)
245							sendACK(&packet, lease->yiaddr);
246						else {
247							/* don't know what to do!!!! */
248							sendNAK(&packet);
249						}
250					}
251				}
252				if (hostname) {
253					bytes = hostname[-1];
254					if (bytes >= (int) sizeof(lease->hostname))
255						bytes = sizeof(lease->hostname) - 1;
256					strncpy(lease->hostname, hostname, bytes);
257					lease->hostname[bytes] = '\0';
258				} else
259					lease->hostname[0] = '\0';
260
261			/* what to do if we have no record of the client */
262			} else if (server_id) {
263				/* SELECTING State */
264
265			} else if (requested) {
266				/* INIT-REBOOT State */
267				if ((lease = find_lease_by_yiaddr(requested_align))) {
268					if (lease_expired(lease)) {
269						/* probably best if we drop this lease */
270						memset(lease->chaddr, 0, 16);
271					/* make some contention for this address */
272					} else sendNAK(&packet);
273				} else if (requested_align < server_config.start ||
274					   requested_align > server_config.end) {
275					sendNAK(&packet);
276				} else {
277					sendNAK(&packet);
278				}
279			} else if (packet.ciaddr) {
280				/* RENEWING or REBINDING State */
281				sendNAK(&packet);
282			}
283			break;
284		case DHCPDECLINE:
285			DEBUG(LOG_INFO,"received DECLINE");
286			if (lease) {
287				memset(lease->chaddr, 0, 16);
288				lease->expires = time(0) + server_config.decline_time;
289			}
290			break;
291		case DHCPRELEASE:
292			DEBUG(LOG_INFO,"received RELEASE");
293			if (lease) lease->expires = time(0);
294			break;
295		case DHCPINFORM:
296			DEBUG(LOG_INFO,"received INFORM");
297			send_inform(&packet);
298			break;
299		default:
300			LOG(LOG_WARNING, "unsupported DHCP message (%02x) -- ignoring", state[0]);
301		}
302	}
303
304	return 0;
305}
306
307