networking/udhcp/dhcpc.c

/* vi: set sw=4 ts=4: */
/* dhcpc.c
 *
 * udhcp DHCP client
 *
 * Russ Dill <Russ.Dill@asu.edu> July 2001
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */

#include <getopt.h>

#include "common.h"
#include "dhcpd.h"
#include "dhcpc.h"
#include "options.h"


static int state;
/* Something is definitely wrong here. IPv4 addresses
 * in variables of type long?? BTW, we use inet_ntoa()
 * in the code. Manpage says that struct in_addr has a member of type long (!)
 * which holds IPv4 address, and the struct is passed by value (!!)
 */
static unsigned long requested_ip; /* = 0 */
static uint32_t server_addr;
static unsigned long timeout;
static int packet_num; /* = 0 */
static int fd = -1;

#define LISTEN_NONE 0
#define LISTEN_KERNEL 1
#define LISTEN_RAW 2
static int listen_mode;

struct client_config_t client_config;


/* just a little helper */
static void change_mode(int new_mode)
{
	DEBUG("entering %s listen mode",
		new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
	if (fd >= 0) close(fd);
	fd = -1;
	listen_mode = new_mode;
}


/* perform a renew */
static void perform_renew(void)
{
	bb_info_msg("Performing a DHCP renew");
	switch (state) {
	case BOUND:
		change_mode(LISTEN_KERNEL);
	case RENEWING:
	case REBINDING:
		state = RENEW_REQUESTED;
		break;
	case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
		udhcp_run_script(NULL, "deconfig");
	case REQUESTING:
	case RELEASED:
		change_mode(LISTEN_RAW);
		state = INIT_SELECTING;
		break;
	case INIT_SELECTING:
		break;
	}

	/* start things over */
	packet_num = 0;

	/* Kill any timeouts because the user wants this to hurry along */
	timeout = 0;
}


/* perform a release */
static void perform_release(void)
{
	char buffer[16];
	struct in_addr temp_addr;

	/* send release packet */
	if (state == BOUND || state == RENEWING || state == REBINDING) {
		temp_addr.s_addr = server_addr;
		sprintf(buffer, "%s", inet_ntoa(temp_addr));
		temp_addr.s_addr = requested_ip;
		bb_info_msg("Unicasting a release of %s to %s",
				inet_ntoa(temp_addr), buffer);
		send_release(server_addr, requested_ip); /* unicast */
		udhcp_run_script(NULL, "deconfig");
	}
	bb_info_msg("Entering released state");

	change_mode(LISTEN_NONE);
	state = RELEASED;
	timeout = 0x7fffffff;
}


static void client_background(void)
{
	udhcp_background(client_config.pidfile);
	client_config.foreground = 1; /* Do not fork again. */
	client_config.background_if_no_lease = 0;
}


static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
{
	uint8_t *storage;
	int len = strlen(str);
	if (len > 255) len = 255;
	storage = xzalloc(len + extra + OPT_DATA);
	storage[OPT_CODE] = code;
	storage[OPT_LEN] = len + extra;
	memcpy(storage + extra + OPT_DATA, str, len);
	return storage;
}


int udhcpc_main(int argc, char *argv[])
{
	uint8_t *temp, *message;
	char *str_c, *str_V, *str_h, *str_F, *str_r, *str_T, *str_t;
	unsigned long t1 = 0, t2 = 0, xid = 0;
	unsigned long start = 0, lease = 0;
	long now;
	unsigned opt;
	int max_fd;
	int sig;
	int retval;
	int len;
	int no_clientid = 0;
	fd_set rfds;
	struct timeval tv;
	struct dhcpMessage packet;
	struct in_addr temp_addr;

	enum {
		OPT_c = 1 << 0,
		OPT_C = 1 << 1,
		OPT_V = 1 << 2,
		OPT_f = 1 << 3,
		OPT_b = 1 << 4,
		OPT_H = 1 << 5,
		OPT_h = 1 << 6,
		OPT_F = 1 << 7,
		OPT_i = 1 << 8,
		OPT_n = 1 << 9,
		OPT_p = 1 << 10,
		OPT_q = 1 << 11,
		OPT_R = 1 << 12,
		OPT_r = 1 << 13,
		OPT_s = 1 << 14,
		OPT_T = 1 << 15,
		OPT_t = 1 << 16,
		OPT_v = 1 << 17,
	};
#if ENABLE_GETOPT_LONG
	static const struct option arg_options[] = {
		{ "clientid",   required_argument,      0, 'c' },
		{ "clientid-none", no_argument,         0, 'C' },
		{ "vendorclass", required_argument,     0, 'V' },
		{ "foreground", no_argument,            0, 'f' },
		{ "background", no_argument,            0, 'b' },
		{ "hostname",   required_argument,      0, 'H' },
		{ "hostname",   required_argument,      0, 'h' },
		{ "fqdn",       required_argument,      0, 'F' },
		{ "interface",  required_argument,      0, 'i' },
		{ "now",        no_argument,            0, 'n' },
		{ "pidfile",    required_argument,      0, 'p' },
		{ "quit",       no_argument,            0, 'q' },
		{ "release",    no_argument,            0, 'R' },
		{ "request",    required_argument,      0, 'r' },
		{ "script",     required_argument,      0, 's' },
		{ "timeout",    required_argument,      0, 'T' },
		{ "version",    no_argument,            0, 'v' },
		{ "retries",    required_argument,      0, 't' },
		{ 0, 0, 0, 0 }
	};
#endif
	/* Default options. */
	client_config.interface = "eth0";
	client_config.script = DEFAULT_SCRIPT;
	client_config.retries = 3;
	client_config.timeout = 3;

	/* Parse command line */
	opt_complementary = "?:c--C:C--c" // mutually exclusive
	                    ":hH:Hh"; // -h and -H are the same
#if ENABLE_GETOPT_LONG
	applet_long_options = arg_options;
#endif
	opt = getopt32(argc, argv, "c:CV:fbH:h:F:i:np:qRr:s:T:t:v",
		&str_c, &str_V, &str_h, &str_h, &str_F,
		&client_config.interface, &client_config.pidfile, &str_r,
		&client_config.script, &str_T, &str_t
		);

	if (opt & OPT_c)
		client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
	if (opt & OPT_C)
		no_clientid = 1;
	if (opt & OPT_V)
		client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
	if (opt & OPT_f)
		client_config.foreground = 1;
	if (opt & OPT_b)
		client_config.background_if_no_lease = 1;
	if (opt & OPT_h)
		client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
	if (opt & OPT_F) {
		client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
		/* Flags: 0000NEOS
		S: 1 => Client requests Server to update A RR in DNS as well as PTR
		O: 1 => Server indicates to client that DNS has been updated regardless
		E: 1 => Name data is DNS format, i.e. <4>host<6>domain<4>com<0> not "host.domain.com"
		N: 1 => Client requests Server to not update DNS
		*/
		client_config.fqdn[OPT_DATA + 0] = 0x1;
		/* client_config.fqdn[OPT_DATA + 1] = 0; - redundant */
		/* client_config.fqdn[OPT_DATA + 2] = 0; - redundant */
	}
	// if (opt & OPT_i) client_config.interface = ...
	if (opt & OPT_n)
		client_config.abort_if_no_lease = 1;
	// if (opt & OPT_p) client_config.pidfile = ...
	if (opt & OPT_q)
		client_config.quit_after_lease = 1;
	if (opt & OPT_R)
		client_config.release_on_quit = 1;
	if (opt & OPT_r)
		requested_ip = inet_addr(str_r);
	// if (opt & OPT_s) client_config.script = ...
	if (opt & OPT_T)
		client_config.timeout = xatoi_u(str_T);
	if (opt & OPT_t)
		client_config.retries = xatoi_u(str_t);
	if (opt & OPT_v) {
		printf("version %s\n\n", BB_VER);
		return 0;
	}

	/* Start the log, sanitize fd's, and write a pid file */
	udhcp_start_log_and_pid(client_config.pidfile);

	if (read_interface(client_config.interface, &client_config.ifindex,
			   NULL, client_config.arp) < 0)
		return 1;

	/* if not set, and not suppressed, setup the default client ID */
	if (!client_config.clientid && !no_clientid) {
		client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
		client_config.clientid[OPT_DATA] = 1;
		memcpy(client_config.clientid + OPT_DATA+1, client_config.arp, 6);
	}

	if (!client_config.vendorclass)
		client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0);

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

	state = INIT_SELECTING;
	udhcp_run_script(NULL, "deconfig");
	change_mode(LISTEN_RAW);

	for (;;) {
		tv.tv_sec = timeout - uptime();
		tv.tv_usec = 0;

		if (listen_mode != LISTEN_NONE && fd < 0) {
			if (listen_mode == LISTEN_KERNEL)
				fd = listen_socket(INADDR_ANY, CLIENT_PORT, client_config.interface);
			else
				fd = raw_socket(client_config.ifindex);
		}
		max_fd = udhcp_sp_fd_set(&rfds, fd);

		if (tv.tv_sec > 0) {
			DEBUG("Waiting on select...");
			retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
		} else retval = 0; /* If we already timed out, fall through */

		now = uptime();
		if (retval == 0) {
			/* timeout dropped to zero */
			switch (state) {
			case INIT_SELECTING:
				if (packet_num < client_config.retries) {
					if (packet_num == 0)
						xid = random_xid();

					/* send discover packet */
					send_discover(xid, requested_ip); /* broadcast */

					timeout = now + client_config.timeout;
					packet_num++;
				} else {
					udhcp_run_script(NULL, "leasefail");
					if (client_config.background_if_no_lease) {
						bb_info_msg("No lease, forking to background");
						client_background();
					} else if (client_config.abort_if_no_lease) {
						bb_info_msg("No lease, failing");
						return 1;
					}
					/* wait to try again */
					packet_num = 0;
					timeout = now + 60;
				}
				break;
			case RENEW_REQUESTED:
			case REQUESTING:
				if (packet_num < client_config.retries) {
					/* send request packet */
					if (state == RENEW_REQUESTED)
						send_renew(xid, server_addr, requested_ip); /* unicast */
					else send_selecting(xid, server_addr, requested_ip); /* broadcast */

					timeout = now + ((packet_num == 2) ? 10 : 2);
					packet_num++;
				} else {
					/* timed out, go back to init state */
					if (state == RENEW_REQUESTED) udhcp_run_script(NULL, "deconfig");
					state = INIT_SELECTING;
					timeout = now;
					packet_num = 0;
					change_mode(LISTEN_RAW);
				}
				break;
			case BOUND:
				/* Lease is starting to run out, time to enter renewing state */
				state = RENEWING;
				change_mode(LISTEN_KERNEL);
				DEBUG("Entering renew state");
				/* fall right through */
			case RENEWING:
				/* Either set a new T1, or enter REBINDING state */
				if ((t2 - t1) <= (lease / 14400 + 1)) {
					/* timed out, enter rebinding state */
					state = REBINDING;
					timeout = now + (t2 - t1);
					DEBUG("Entering rebinding state");
				} else {
					/* send a request packet */
					send_renew(xid, server_addr, requested_ip); /* unicast */

					t1 = (t2 - t1) / 2 + t1;
					timeout = t1 + start;
				}
				break;
			case REBINDING:
				/* Either set a new T2, or enter INIT state */
				if ((lease - t2) <= (lease / 14400 + 1)) {
					/* timed out, enter init state */
					state = INIT_SELECTING;
					bb_info_msg("Lease lost, entering init state");
					udhcp_run_script(NULL, "deconfig");
					timeout = now;
					packet_num = 0;
					change_mode(LISTEN_RAW);
				} else {
					/* send a request packet */
					send_renew(xid, 0, requested_ip); /* broadcast */

					t2 = (lease - t2) / 2 + t2;
					timeout = t2 + start;
				}
				break;
			case RELEASED:
				/* yah, I know, *you* say it would never happen */
				timeout = 0x7fffffff;
				break;
			}
		} else if (retval > 0 && listen_mode != LISTEN_NONE && FD_ISSET(fd, &rfds)) {
			/* a packet is ready, read it */

			if (listen_mode == LISTEN_KERNEL)
				len = udhcp_get_packet(&packet, fd);
			else len = get_raw_packet(&packet, fd);

			if (len == -1 && errno != EINTR) {
				DEBUG("error on read, %s, reopening socket", strerror(errno));
				change_mode(listen_mode); /* just close and reopen */
			}
			if (len < 0) continue;

			if (packet.xid != xid) {
				DEBUG("Ignoring XID %lx (our xid is %lx)",
					(unsigned long) packet.xid, xid);
				continue;
			}

			/* Ignore packets that aren't for us */
			if (memcmp(packet.chaddr, client_config.arp, 6)) {
				DEBUG("Packet does not have our chaddr - ignoring");
				continue;
			}

			if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
				bb_error_msg("cannot get option from packet - ignoring");
				continue;
			}

			switch (state) {
			case INIT_SELECTING:
				/* Must be a DHCPOFFER to one of our xid's */
				if (*message == DHCPOFFER) {
					temp = get_option(&packet, DHCP_SERVER_ID);
					if (temp) {
						/* can be misaligned, thus memcpy */
						memcpy(&server_addr, temp, 4);
						xid = packet.xid;
						requested_ip = packet.yiaddr;

						/* enter requesting state */
						state = REQUESTING;
						timeout = now;
						packet_num = 0;
					} else {
						bb_error_msg("no server ID in message");
					}
				}
				break;
			case RENEW_REQUESTED:
			case REQUESTING:
			case RENEWING:
			case REBINDING:
				if (*message == DHCPACK) {
					temp = get_option(&packet, DHCP_LEASE_TIME);
					if (!temp) {
						bb_error_msg("no lease time with ACK, using 1 hour lease");
						lease = 60 * 60;
					} else {
						/* can be misaligned, thus memcpy */
						memcpy(&lease, temp, 4);
						lease = ntohl(lease);
					}

					/* enter bound state */
					t1 = lease / 2;

					/* little fixed point for n * .875 */
					t2 = (lease * 0x7) >> 3;
					temp_addr.s_addr = packet.yiaddr;
					bb_info_msg("Lease of %s obtained, lease time %ld",
						inet_ntoa(temp_addr), lease);
					start = now;
					timeout = t1 + start;
					requested_ip = packet.yiaddr;
					udhcp_run_script(&packet,
						   ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));

					state = BOUND;
					change_mode(LISTEN_NONE);
					if (client_config.quit_after_lease) {
						if (client_config.release_on_quit)
							perform_release();
						return 0;
					}
					if (!client_config.foreground)
						client_background();

				} else if (*message == DHCPNAK) {
					/* return to init state */
					bb_info_msg("Received DHCP NAK");
					udhcp_run_script(&packet, "nak");
					if (state != REQUESTING)
						udhcp_run_script(NULL, "deconfig");
					state = INIT_SELECTING;
					timeout = now;
					requested_ip = 0;
					packet_num = 0;
					change_mode(LISTEN_RAW);
					sleep(3); /* avoid excessive network traffic */
				}
				break;
			/* case BOUND, RELEASED: - ignore all packets */
			}
		} else if (retval > 0 && (sig = udhcp_sp_read(&rfds))) {
			switch (sig) {
			case SIGUSR1:
				perform_renew();
				break;
			case SIGUSR2:
				perform_release();
				break;
			case SIGTERM:
				bb_info_msg("Received SIGTERM");
				if (client_config.release_on_quit)
					perform_release();
				return 0;
			}
		} else if (retval == -1 && errno == EINTR) {
			/* a signal was caught */
		} else {
			/* An error occured */
			bb_perror_msg("select");
		}

	}
	return 0;
}
1	/* vi: set sw=4 ts=4: */
2	/* dhcpc.c
3	*
4	* udhcp DHCP client
5	*
6	* Russ Dill <Russ.Dill@asu.edu> July 2001
7	*
8	* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
9	*/
10
11	#include <getopt.h>
12
13	#include "common.h"
14	#include "dhcpd.h"
15	#include "dhcpc.h"
16	#include "options.h"
17
18
19	static int state;
20	/* Something is definitely wrong here. IPv4 addresses
21	* in variables of type long?? BTW, we use inet_ntoa()
22	* in the code. Manpage says that struct in_addr has a member of type long (!)
23	* which holds IPv4 address, and the struct is passed by value (!!)
24	*/
25	static unsigned long requested_ip; /* = 0 */
26	static uint32_t server_addr;
27	static unsigned long timeout;
28	static int packet_num; /* = 0 */
29	static int fd = -1;
30
31	#define LISTEN_NONE 0
32	#define LISTEN_KERNEL 1
33	#define LISTEN_RAW 2
34	static int listen_mode;
35
36	struct client_config_t client_config;
37
38
39	/* just a little helper */
40	static void change_mode(int new_mode)
41	{
42	DEBUG("entering %s listen mode",
43	new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
44	if (fd >= 0) close(fd);
45	fd = -1;
46	listen_mode = new_mode;
47	}
48
49
50	/* perform a renew */
51	static void perform_renew(void)
52	{
53	bb_info_msg("Performing a DHCP renew");
54	switch (state) {
55	case BOUND:
56	change_mode(LISTEN_KERNEL);
57	case RENEWING:
58	case REBINDING:
59	state = RENEW_REQUESTED;
60	break;
61	case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
62	udhcp_run_script(NULL, "deconfig");
63	case REQUESTING:
64	case RELEASED:
65	change_mode(LISTEN_RAW);
66	state = INIT_SELECTING;
67	break;
68	case INIT_SELECTING:
69	break;
70	}
71
72	/* start things over */
73	packet_num = 0;
74
75	/* Kill any timeouts because the user wants this to hurry along */
76	timeout = 0;
77	}
78
79
80	/* perform a release */
81	static void perform_release(void)
82	{
83	char buffer[16];
84	struct in_addr temp_addr;
85
86	/* send release packet */
87	if (state == BOUND \|\| state == RENEWING \|\| state == REBINDING) {
88	temp_addr.s_addr = server_addr;
89	sprintf(buffer, "%s", inet_ntoa(temp_addr));
90	temp_addr.s_addr = requested_ip;
91	bb_info_msg("Unicasting a release of %s to %s",
92	inet_ntoa(temp_addr), buffer);
93	send_release(server_addr, requested_ip); /* unicast */
94	udhcp_run_script(NULL, "deconfig");
95	}
96	bb_info_msg("Entering released state");
97
98	change_mode(LISTEN_NONE);
99	state = RELEASED;
100	timeout = 0x7fffffff;
101	}
102
103
104	static void client_background(void)
105	{
106	udhcp_background(client_config.pidfile);
107	client_config.foreground = 1; /* Do not fork again. */
108	client_config.background_if_no_lease = 0;
109	}
110
111
112	static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
113	{
114	uint8_t *storage;
115	int len = strlen(str);
116	if (len > 255) len = 255;
117	storage = xzalloc(len + extra + OPT_DATA);
118	storage[OPT_CODE] = code;
119	storage[OPT_LEN] = len + extra;
120	memcpy(storage + extra + OPT_DATA, str, len);
121	return storage;
122	}
123
124
125	int udhcpc_main(int argc, char *argv[])
126	{
127	uint8_t temp, message;
128	char str_c, str_V, str_h, str_F, str_r, str_T, *str_t;
129	unsigned long t1 = 0, t2 = 0, xid = 0;
130	unsigned long start = 0, lease = 0;
131	long now;
132	unsigned opt;
133	int max_fd;
134	int sig;
135	int retval;
136	int len;
137	int no_clientid = 0;
138	fd_set rfds;
139	struct timeval tv;
140	struct dhcpMessage packet;
141	struct in_addr temp_addr;
142
143	enum {
144	OPT_c = 1 << 0,
145	OPT_C = 1 << 1,
146	OPT_V = 1 << 2,
147	OPT_f = 1 << 3,
148	OPT_b = 1 << 4,
149	OPT_H = 1 << 5,
150	OPT_h = 1 << 6,
151	OPT_F = 1 << 7,
152	OPT_i = 1 << 8,
153	OPT_n = 1 << 9,
154	OPT_p = 1 << 10,
155	OPT_q = 1 << 11,
156	OPT_R = 1 << 12,
157	OPT_r = 1 << 13,
158	OPT_s = 1 << 14,
159	OPT_T = 1 << 15,
160	OPT_t = 1 << 16,
161	OPT_v = 1 << 17,
162	};
163	#if ENABLE_GETOPT_LONG
164	static const struct option arg_options[] = {
165	{ "clientid", required_argument, 0, 'c' },
166	{ "clientid-none", no_argument, 0, 'C' },
167	{ "vendorclass", required_argument, 0, 'V' },
168	{ "foreground", no_argument, 0, 'f' },
169	{ "background", no_argument, 0, 'b' },
170	{ "hostname", required_argument, 0, 'H' },
171	{ "hostname", required_argument, 0, 'h' },
172	{ "fqdn", required_argument, 0, 'F' },
173	{ "interface", required_argument, 0, 'i' },
174	{ "now", no_argument, 0, 'n' },
175	{ "pidfile", required_argument, 0, 'p' },
176	{ "quit", no_argument, 0, 'q' },
177	{ "release", no_argument, 0, 'R' },
178	{ "request", required_argument, 0, 'r' },
179	{ "script", required_argument, 0, 's' },
180	{ "timeout", required_argument, 0, 'T' },
181	{ "version", no_argument, 0, 'v' },
182	{ "retries", required_argument, 0, 't' },
183	{ 0, 0, 0, 0 }
184	};
185	#endif
186	/* Default options. */
187	client_config.interface = "eth0";
188	client_config.script = DEFAULT_SCRIPT;
189	client_config.retries = 3;
190	client_config.timeout = 3;
191
192	/* Parse command line */
193	opt_complementary = "?:c--C:C--c" // mutually exclusive
194	":hH:Hh"; // -h and -H are the same
195	#if ENABLE_GETOPT_LONG
196	applet_long_options = arg_options;
197	#endif
198	opt = getopt32(argc, argv, "c:CV:fbH:h:F:i:np:qRr:s:T:t:v",
199	&str_c, &str_V, &str_h, &str_h, &str_F,
200	&client_config.interface, &client_config.pidfile, &str_r,
201	&client_config.script, &str_T, &str_t
202	);
203
204	if (opt & OPT_c)
205	client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
206	if (opt & OPT_C)
207	no_clientid = 1;
208	if (opt & OPT_V)
209	client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
210	if (opt & OPT_f)
211	client_config.foreground = 1;
212	if (opt & OPT_b)
213	client_config.background_if_no_lease = 1;
214	if (opt & OPT_h)
215	client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
216	if (opt & OPT_F) {
217	client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
218	/* Flags: 0000NEOS
219	S: 1 => Client requests Server to update A RR in DNS as well as PTR
220	O: 1 => Server indicates to client that DNS has been updated regardless
221	E: 1 => Name data is DNS format, i.e. <4>host<6>domain<4>com<0> not "host.domain.com"
222	N: 1 => Client requests Server to not update DNS
223	*/
224	client_config.fqdn[OPT_DATA + 0] = 0x1;
225	/* client_config.fqdn[OPT_DATA + 1] = 0; - redundant */
226	/* client_config.fqdn[OPT_DATA + 2] = 0; - redundant */
227	}
228	// if (opt & OPT_i) client_config.interface = ...
229	if (opt & OPT_n)
230	client_config.abort_if_no_lease = 1;
231	// if (opt & OPT_p) client_config.pidfile = ...
232	if (opt & OPT_q)
233	client_config.quit_after_lease = 1;
234	if (opt & OPT_R)
235	client_config.release_on_quit = 1;
236	if (opt & OPT_r)
237	requested_ip = inet_addr(str_r);
238	// if (opt & OPT_s) client_config.script = ...
239	if (opt & OPT_T)
240	client_config.timeout = xatoi_u(str_T);
241	if (opt & OPT_t)
242	client_config.retries = xatoi_u(str_t);
243	if (opt & OPT_v) {
244	printf("version %s\n\n", BB_VER);
245	return 0;
246	}
247
248	/* Start the log, sanitize fd's, and write a pid file */
249	udhcp_start_log_and_pid(client_config.pidfile);
250
251	if (read_interface(client_config.interface, &client_config.ifindex,
252	NULL, client_config.arp) < 0)
253	return 1;
254
255	/* if not set, and not suppressed, setup the default client ID */
256	if (!client_config.clientid && !no_clientid) {
257	client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
258	client_config.clientid[OPT_DATA] = 1;
259	memcpy(client_config.clientid + OPT_DATA+1, client_config.arp, 6);
260	}
261
262	if (!client_config.vendorclass)
263	client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0);
264
265	/* setup the signal pipe */
266	udhcp_sp_setup();
267
268	state = INIT_SELECTING;
269	udhcp_run_script(NULL, "deconfig");
270	change_mode(LISTEN_RAW);
271
272	for (;;) {
273	tv.tv_sec = timeout - uptime();
274	tv.tv_usec = 0;
275
276	if (listen_mode != LISTEN_NONE && fd < 0) {
277	if (listen_mode == LISTEN_KERNEL)
278	fd = listen_socket(INADDR_ANY, CLIENT_PORT, client_config.interface);
279	else
280	fd = raw_socket(client_config.ifindex);
281	}
282	max_fd = udhcp_sp_fd_set(&rfds, fd);
283
284	if (tv.tv_sec > 0) {
285	DEBUG("Waiting on select...");
286	retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
287	} else retval = 0; /* If we already timed out, fall through */
288
289	now = uptime();
290	if (retval == 0) {
291	/* timeout dropped to zero */
292	switch (state) {
293	case INIT_SELECTING:
294	if (packet_num < client_config.retries) {
295	if (packet_num == 0)
296	xid = random_xid();
297
298	/* send discover packet */
299	send_discover(xid, requested_ip); /* broadcast */
300
301	timeout = now + client_config.timeout;
302	packet_num++;
303	} else {
304	udhcp_run_script(NULL, "leasefail");
305	if (client_config.background_if_no_lease) {
306	bb_info_msg("No lease, forking to background");
307	client_background();
308	} else if (client_config.abort_if_no_lease) {
309	bb_info_msg("No lease, failing");
310	return 1;
311	}
312	/* wait to try again */
313	packet_num = 0;
314	timeout = now + 60;
315	}
316	break;
317	case RENEW_REQUESTED:
318	case REQUESTING:
319	if (packet_num < client_config.retries) {
320	/* send request packet */
321	if (state == RENEW_REQUESTED)
322	send_renew(xid, server_addr, requested_ip); /* unicast */
323	else send_selecting(xid, server_addr, requested_ip); /* broadcast */
324
325	timeout = now + ((packet_num == 2) ? 10 : 2);
326	packet_num++;
327	} else {
328	/* timed out, go back to init state */
329	if (state == RENEW_REQUESTED) udhcp_run_script(NULL, "deconfig");
330	state = INIT_SELECTING;
331	timeout = now;
332	packet_num = 0;
333	change_mode(LISTEN_RAW);
334	}
335	break;
336	case BOUND:
337	/* Lease is starting to run out, time to enter renewing state */
338	state = RENEWING;
339	change_mode(LISTEN_KERNEL);
340	DEBUG("Entering renew state");
341	/* fall right through */
342	case RENEWING:
343	/* Either set a new T1, or enter REBINDING state */
344	if ((t2 - t1) <= (lease / 14400 + 1)) {
345	/* timed out, enter rebinding state */
346	state = REBINDING;
347	timeout = now + (t2 - t1);
348	DEBUG("Entering rebinding state");
349	} else {
350	/* send a request packet */
351	send_renew(xid, server_addr, requested_ip); /* unicast */
352
353	t1 = (t2 - t1) / 2 + t1;
354	timeout = t1 + start;
355	}
356	break;
357	case REBINDING:
358	/* Either set a new T2, or enter INIT state */
359	if ((lease - t2) <= (lease / 14400 + 1)) {
360	/* timed out, enter init state */
361	state = INIT_SELECTING;
362	bb_info_msg("Lease lost, entering init state");
363	udhcp_run_script(NULL, "deconfig");
364	timeout = now;
365	packet_num = 0;
366	change_mode(LISTEN_RAW);
367	} else {
368	/* send a request packet */
369	send_renew(xid, 0, requested_ip); /* broadcast */
370
371	t2 = (lease - t2) / 2 + t2;
372	timeout = t2 + start;
373	}
374	break;
375	case RELEASED:
376	/* yah, I know, you say it would never happen */
377	timeout = 0x7fffffff;
378	break;
379	}
380	} else if (retval > 0 && listen_mode != LISTEN_NONE && FD_ISSET(fd, &rfds)) {
381	/* a packet is ready, read it */
382
383	if (listen_mode == LISTEN_KERNEL)
384	len = udhcp_get_packet(&packet, fd);
385	else len = get_raw_packet(&packet, fd);
386
387	if (len == -1 && errno != EINTR) {
388	DEBUG("error on read, %s, reopening socket", strerror(errno));
389	change_mode(listen_mode); /* just close and reopen */
390	}
391	if (len < 0) continue;
392
393	if (packet.xid != xid) {
394	DEBUG("Ignoring XID %lx (our xid is %lx)",
395	(unsigned long) packet.xid, xid);
396	continue;
397	}
398
399	/* Ignore packets that aren't for us */
400	if (memcmp(packet.chaddr, client_config.arp, 6)) {
401	DEBUG("Packet does not have our chaddr - ignoring");
402	continue;
403	}
404
405	if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
406	bb_error_msg("cannot get option from packet - ignoring");
407	continue;
408	}
409
410	switch (state) {
411	case INIT_SELECTING:
412	/* Must be a DHCPOFFER to one of our xid's */
413	if (*message == DHCPOFFER) {
414	temp = get_option(&packet, DHCP_SERVER_ID);
415	if (temp) {
416	/* can be misaligned, thus memcpy */
417	memcpy(&server_addr, temp, 4);
418	xid = packet.xid;
419	requested_ip = packet.yiaddr;
420
421	/* enter requesting state */
422	state = REQUESTING;
423	timeout = now;
424	packet_num = 0;
425	} else {
426	bb_error_msg("no server ID in message");
427	}
428	}
429	break;
430	case RENEW_REQUESTED:
431	case REQUESTING:
432	case RENEWING:
433	case REBINDING:
434	if (*message == DHCPACK) {
435	temp = get_option(&packet, DHCP_LEASE_TIME);
436	if (!temp) {
437	bb_error_msg("no lease time with ACK, using 1 hour lease");
438	lease = 60 * 60;
439	} else {
440	/* can be misaligned, thus memcpy */
441	memcpy(&lease, temp, 4);
442	lease = ntohl(lease);
443	}
444
445	/* enter bound state */
446	t1 = lease / 2;
447
448	/* little fixed point for n * .875 */
449	t2 = (lease * 0x7) >> 3;
450	temp_addr.s_addr = packet.yiaddr;
451	bb_info_msg("Lease of %s obtained, lease time %ld",
452	inet_ntoa(temp_addr), lease);
453	start = now;
454	timeout = t1 + start;
455	requested_ip = packet.yiaddr;
456	udhcp_run_script(&packet,
457	((state == RENEWING \|\| state == REBINDING) ? "renew" : "bound"));
458
459	state = BOUND;
460	change_mode(LISTEN_NONE);
461	if (client_config.quit_after_lease) {
462	if (client_config.release_on_quit)
463	perform_release();
464	return 0;
465	}
466	if (!client_config.foreground)
467	client_background();
468
469	} else if (*message == DHCPNAK) {
470	/* return to init state */
471	bb_info_msg("Received DHCP NAK");
472	udhcp_run_script(&packet, "nak");
473	if (state != REQUESTING)
474	udhcp_run_script(NULL, "deconfig");
475	state = INIT_SELECTING;
476	timeout = now;
477	requested_ip = 0;
478	packet_num = 0;
479	change_mode(LISTEN_RAW);
480	sleep(3); /* avoid excessive network traffic */
481	}
482	break;
483	/* case BOUND, RELEASED: - ignore all packets */
484	}
485	} else if (retval > 0 && (sig = udhcp_sp_read(&rfds))) {
486	switch (sig) {
487	case SIGUSR1:
488	perform_renew();
489	break;
490	case SIGUSR2:
491	perform_release();
492	break;
493	case SIGTERM:
494	bb_info_msg("Received SIGTERM");
495	if (client_config.release_on_quit)
496	perform_release();
497	return 0;
498	}
499	} else if (retval == -1 && errno == EINTR) {
500	/* a signal was caught */
501	} else {
502	/* An error occured */
503	bb_perror_msg("select");
504	}
505
506	}
507	return 0;
508	}