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
53
54/* globals */
55struct dhcpOfferedAddr *leases;
56struct server_config_t server_config;
57static int signal_pipe[2];
58
59/* Exit and cleanup */
60static void exit_server(int retval)
61{
62	pidfile_delete(server_config.pidfile);
63	CLOSE_LOG();
64	exit(retval);
65}
66
67
68/* Signal handler */
69static void signal_handler(int sig)
70{
71	if (send(signal_pipe[1], &sig, sizeof(sig), MSG_DONTWAIT) < 0) {
72		LOG(LOG_ERR, "Could not send signal: %s",
73			strerror(errno));
74	}
75}
76
77#ifdef COMBINED_BINARY
78int udhcpd_main(int argc, char *argv[])
79#else
80int main(int argc, char *argv[])
81#endif
82{
83	fd_set rfds;
84	struct timeval tv;
85	int server_socket = -1;
86	int bytes, retval;
87	struct dhcpMessage packet;
88	unsigned char *state;
89	unsigned char *server_id, *requested, *hostname;
90	u_int32_t server_id_align, requested_align;
91	unsigned long timeout_end;
92	struct option_set *option;
93	struct dhcpOfferedAddr *lease;
94	int pid_fd;
95	int max_sock;
96	int sig;
97
98	OPEN_LOG("udhcpd");
99	LOG(LOG_INFO, "udhcp server (v%s) started", VERSION);
100
101	memset(&server_config, 0, sizeof(struct server_config_t));
102
103	if (argc < 2)
104		read_config(DHCPD_CONF_FILE);
105	else read_config(argv[1]);
106
107    /*get reserved ip from configuration file*/
108    num_of_reservedIP = getReservedAddr(resrvMacAddr, resrvIpAddr);
109
110	pid_fd = pidfile_acquire(server_config.pidfile);
111	pidfile_write_release(pid_fd);
112
113	if ((option = find_option(server_config.options, DHCP_LEASE_TIME))) {
114		memcpy(&server_config.lease, option->data + 2, 4);
115		server_config.lease = ntohl(server_config.lease);
116	}
117	else server_config.lease = LEASE_TIME;
118
119	leases = malloc(sizeof(struct dhcpOfferedAddr) * server_config.max_leases);
120	memset(leases, 0, sizeof(struct dhcpOfferedAddr) * server_config.max_leases);
121	read_leases(server_config.lease_file);
122
123	if (read_interface(server_config.interface, &server_config.ifindex,
124			   &server_config.server, server_config.arp) < 0)
125		exit_server(1);
126
127#ifndef DEBUGGING
128	pid_fd = pidfile_acquire(server_config.pidfile); /* hold lock during fork. */
129	if (daemon(0, 0) == -1) {
130		perror("fork");
131		exit_server(1);
132	}
133	pidfile_write_release(pid_fd);
134#endif
135
136
137	socketpair(AF_UNIX, SOCK_STREAM, 0, signal_pipe);
138	signal(SIGUSR1, signal_handler);
139	signal(SIGTERM, signal_handler);
140
141	timeout_end = time(0) + server_config.auto_time;
142	while(1) { /* loop until universe collapses */
143
144		if (server_socket < 0)
145			if ((server_socket = listen_socket(INADDR_ANY, SERVER_PORT, server_config.interface)) < 0) {
146				LOG(LOG_ERR, "FATAL: couldn't create server socket, %s", strerror(errno));
147				exit_server(0);
148			}
149
150		FD_ZERO(&rfds);
151		FD_SET(server_socket, &rfds);
152		FD_SET(signal_pipe[0], &rfds);
153		if (server_config.auto_time) {
154			tv.tv_sec = timeout_end - time(0);
155			tv.tv_usec = 0;
156		}
157		if (!server_config.auto_time || tv.tv_sec > 0) {
158			max_sock = server_socket > signal_pipe[0] ? server_socket : signal_pipe[0];
159			retval = select(max_sock + 1, &rfds, NULL, NULL,
160					server_config.auto_time ? &tv : NULL);
161		} else retval = 0; /* If we already timed out, fall through */
162
163		if (retval == 0) {
164			write_leases();
165			timeout_end = time(0) + server_config.auto_time;
166			continue;
167		} else if (retval < 0 && errno != EINTR) {
168			DEBUG(LOG_INFO, "error on select");
169			continue;
170		}
171
172		if (FD_ISSET(signal_pipe[0], &rfds)) {
173			if (read(signal_pipe[0], &sig, sizeof(sig)) < 0)
174				continue; /* probably just EINTR */
175			switch (sig) {
176			case SIGUSR1:
177				LOG(LOG_INFO, "Received a SIGUSR1");
178				write_leases();
179				/* why not just reset the timeout, eh */
180				timeout_end = time(0) + server_config.auto_time;
181				continue;
182			case SIGTERM:
183				LOG(LOG_INFO, "Received a SIGTERM");
184				exit_server(0);
185			}
186		}
187
188		if ((bytes = get_packet(&packet, server_socket)) < 0) { /* this waits for a packet - idle */
189			if (bytes == -1 && errno != EINTR) {
190				DEBUG(LOG_INFO, "error on read, %s, reopening socket", strerror(errno));
191				close(server_socket);
192				server_socket = -1;
193			}
194			continue;
195		}
196
197		if ((state = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
198			DEBUG(LOG_ERR, "couldn't get option from packet, ignoring");
199			continue;
200		}
201
202		/* ADDME: look for a static lease */
203		lease = find_lease_by_chaddr(packet.chaddr);
204		switch (state[0]) {
205		case DHCPDISCOVER:
206			DEBUG(LOG_INFO,"received DISCOVER");
207
208			if (sendOffer(&packet) < 0) {
209				LOG(LOG_ERR, "send OFFER failed");
210			}
211			break;
212 		case DHCPREQUEST:
213        {
214 		    /* foxcon added start by EricHuang, 03/01/2007 */
215 		    unsigned char mac[6];
216 		    u_int32_t r_addr;
217 		    memcpy(mac, packet.chaddr, 6);
218 		    /* foxcon added end by EricHuang, 03/01/2007 */
219
220			DEBUG(LOG_INFO, "received REQUEST");
221
222			requested = get_option(&packet, DHCP_REQUESTED_IP);
223			server_id = get_option(&packet, DHCP_SERVER_ID);
224			hostname = get_option(&packet, DHCP_HOST_NAME);
225
226			if (requested) memcpy(&requested_align, requested, 4);
227			/* Foxconn added start pling 08/03/2011 */
228			/* Should clear this var, otherwise it keeps old value
229			 * (from previous packet) and cause reserved IP client
230			 * to get NAK.
231			 */
232			else
233				requested_align = 0;
234			/* Foxconn added end pling 08/03/2011 */
235			if (server_id) memcpy(&server_id_align, server_id, 4);
236
237            /* foxcon added start by EricHuang, 03/01/2007 */
238            r_addr = find_reserved_ip(mac);
239            if (r_addr) {
240                if (requested_align)
241                {
242                    if ( requested_align!=htonl(r_addr))
243                    {
244                        sendNAK(&packet);
245                        DEBUG(LOG_INFO, "prepare to send a reserved ip (0x%x, 0x%x)\n", requested_align, htonl(r_addr));
246                        break;
247                    }
248                }
249            }
250            /* foxcon added end by EricHuang, 03/01/2007 */
251
252			if (lease) { /*ADDME: or static lease */
253				if (server_id) {
254					/* SELECTING State */
255					DEBUG(LOG_INFO, "server_id = %08x", ntohl(server_id_align));
256					if (server_id_align == server_config.server && requested &&
257					    requested_align == lease->yiaddr) {
258						sendACK(&packet, lease->yiaddr);
259					}
260				} else {
261					if (requested) {
262						/* INIT-REBOOT State */
263						if (lease->yiaddr == requested_align)
264							sendACK(&packet, lease->yiaddr);
265						else sendNAK(&packet);
266					} else {
267						/* RENEWING or REBINDING State */
268						if (lease->yiaddr == packet.ciaddr)
269							sendACK(&packet, lease->yiaddr);
270						else {
271							/* don't know what to do!!!! */
272							sendNAK(&packet);
273						}
274					}
275				}
276				if (hostname) {
277					bytes = hostname[-1];
278					if (bytes >= (int) sizeof(lease->hostname))
279						bytes = sizeof(lease->hostname) - 1;
280					strncpy(lease->hostname, hostname, bytes);
281					lease->hostname[bytes] = '\0';
282                    DEBUG(LOG_INFO,"rewrite leass table, hostname: %s\n", lease->hostname);
283                    /* foxconn wklin removed, 05/07/2007 */
284                    /* write_leases(); */ /*Rewrite lease table into file.*/
285				} else
286					lease->hostname[0] = '\0';
287                /* foxconn wklin added, 05/07/2007 */
288                write_leases(); /*Rewrite lease table into file.*/
289
290			/* what to do if we have no record of the client */
291			} else if (server_id) {
292				/* SELECTING State */
293
294			} else if (requested) {
295				/* INIT-REBOOT State */
296				if ((lease = find_lease_by_yiaddr(requested_align))) {
297					if (lease_expired(lease)) {
298						/* probably best if we drop this lease */
299						memset(lease->chaddr, 0, 16);
300                        write_leases(); /*Rewrite lease table into file.*/
301					/* make some contention for this address */
302					} else sendNAK(&packet);
303				} else if (requested_align < server_config.start ||
304					   requested_align > server_config.end) {
305					sendNAK(&packet);
306				} else {
307					sendNAK(&packet);
308				}
309
310			} else if (packet.ciaddr) {
311				/* RENEWING or REBINDING State */
312				sendNAK(&packet);
313			}
314			break;
315		}
316		case DHCPDECLINE:
317			DEBUG(LOG_INFO,"received DECLINE");
318			if (lease) {
319				memset(lease->chaddr, 0, 16);
320				lease->expires = time(0) + server_config.decline_time;
321                write_leases(); /*Rewrite lease table into file.*/
322			}
323			break;
324		case DHCPRELEASE:
325			DEBUG(LOG_INFO,"received RELEASE");
326			if (lease)
327            {
328                lease->expires = time(0);
329                write_leases(); /*Rewrite lease table into file.*/
330            }
331			break;
332		case DHCPINFORM:
333			DEBUG(LOG_INFO,"received INFORM");
334			send_inform(&packet);
335			break;
336		default:
337			LOG(LOG_WARNING, "unsupported DHCP message (%02x) -- ignoring", state[0]);
338		}
339	}
340
341	return 0;
342}
343
344