add back in udhcp support

1 files changed, 574 insertions, 0 deletions

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
new file mode 100644
index 0000000..222bd65
--- /dev/null
+++ b/networking/udhcp/dhcpc.c
@@ -0,0 +1,574 @@
+/* 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 <sys/time.h>
+#include <sys/file.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <signal.h>
+#include <time.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <errno.h>
+
+#include "common.h"
+#include "dhcpd.h"
+#include "dhcpc.h"
+#include "options.h"
+#include "clientpacket.h"
+#include "clientsocket.h"
+#include "script.h"
+#include "socket.h"
+#include "signalpipe.h"
+
+static int state;
+static unsigned long requested_ip; /* = 0 */
+static unsigned long 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 = {
+	/* Default options. */
+	.abort_if_no_lease = 0,
+	.foreground = 0,
+	.quit_after_lease = 0,
+	.background_if_no_lease = 0,
+	.interface = "eth0",
+	.pidfile = NULL,
+	.script = DEFAULT_SCRIPT,
+	.clientid = NULL,
+	.vendorclass = NULL,
+	.hostname = NULL,
+	.fqdn = NULL,
+	.ifindex = 0,
+	.retries = 3,
+	.timeout = 3,
+	.arp = "\0\0\0\0\0\0",		/* appease gcc-3.0 */
+};
+
+#ifndef IN_BUSYBOX
+static void ATTRIBUTE_NORETURN show_usage(void)
+{
+	printf(
+"Usage: udhcpc [OPTIONS]\n\n"
+"  -c, --clientid=CLIENTID         Set client identifier - type is first char\n"
+"  -C, --clientid-none             Suppress default client identifier\n"
+"  -V, --vendorclass=CLASSID       Set vendor class identifier\n"
+"  -H, --hostname=HOSTNAME         Client hostname\n"
+"  -h                              Alias for -H\n"
+"  -F, --fqdn=FQDN                 Client fully qualified domain name\n"
+"  -f, --foreground                Do not fork after getting lease\n"
+"  -b, --background                Fork to background if lease cannot be\n"
+"                                  immediately negotiated.\n"
+"  -i, --interface=INTERFACE       Interface to use (default: eth0)\n"
+"  -n, --now                       Exit with failure if lease cannot be\n"
+"                                  immediately negotiated.\n"
+"  -p, --pidfile=file              Store process ID of daemon in file\n"
+"  -q, --quit                      Quit after obtaining lease\n"
+"  -r, --request=IP                IP address to request (default: none)\n"
+"  -s, --script=file               Run file at dhcp events (default:\n"
+"                                  " DEFAULT_SCRIPT ")\n"
+"  -T, --timeout=seconds           Try to get the lease for the amount of\n"
+"                                  seconds (default: 3)\n"
+"  -t, --retries=NUM               Send up to NUM request packets\n"
+"  -v, --version                   Display version\n"
+	);
+	exit(0);
+}
+#else
+#define show_usage bb_show_usage
+extern void show_usage(void) ATTRIBUTE_NORETURN;
+#endif
+
+
+/* just a little helper */
+static void change_mode(int new_mode)
+{
+	DEBUG(LOG_INFO, "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)
+{
+	LOG(LOG_INFO, "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 */
+		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;
+		LOG(LOG_INFO, "Unicasting a release of %s to %s",
+				inet_ntoa(temp_addr), buffer);
+		send_release(server_addr, requested_ip); /* unicast */
+		run_script(NULL, "deconfig");
+	}
+	LOG(LOG_INFO, "Entering released state");
+
+	change_mode(LISTEN_NONE);
+	state = RELEASED;
+	timeout = 0x7fffffff;
+}
+
+
+static void client_background(void)
+{
+	background(client_config.pidfile);
+	client_config.foreground = 1; /* Do not fork again. */
+	client_config.background_if_no_lease = 0;
+}
+
+
+#ifdef COMBINED_BINARY
+int udhcpc_main(int argc, char *argv[])
+#else
+int main(int argc, char *argv[])
+#endif
+{
+	uint8_t *temp, *message;
+	unsigned long t1 = 0, t2 = 0, xid = 0;
+	unsigned long start = 0, lease;
+	fd_set rfds;
+	int retval;
+	struct timeval tv;
+	int c, len;
+	struct dhcpMessage packet;
+	struct in_addr temp_addr;
+	long now;
+	int max_fd;
+	int sig;
+	int no_clientid = 0;
+
+	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'},
+		{"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}
+	};
+
+	/* get options */
+	while (1) {
+		int option_index = 0;
+		c = getopt_long(argc, argv, "c:CV:fbH:h:F:i:np:qr:s:T:t:v", arg_options, &option_index);
+		if (c == -1) break;
+
+		switch (c) {
+		case 'c':
+			if (no_clientid) show_usage();
+			len = strlen(optarg) > 255 ? 255 : strlen(optarg);
+			free(client_config.clientid);
+			client_config.clientid = xmalloc(len + 2);
+			client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
+			client_config.clientid[OPT_LEN] = len;
+			client_config.clientid[OPT_DATA] = '\0';
+			strncpy((char*)client_config.clientid + OPT_DATA, optarg, len);
+			break;
+		case 'C':
+			if (client_config.clientid) show_usage();
+			no_clientid = 1;
+			break;
+		case 'V':
+			len = strlen(optarg) > 255 ? 255 : strlen(optarg);
+			free(client_config.vendorclass);
+			client_config.vendorclass = xmalloc(len + 2);
+			client_config.vendorclass[OPT_CODE] = DHCP_VENDOR;
+			client_config.vendorclass[OPT_LEN] = len;
+			strncpy((char*)client_config.vendorclass + OPT_DATA, optarg, len);
+			break;
+		case 'f':
+			client_config.foreground = 1;
+			break;
+		case 'b':
+			client_config.background_if_no_lease = 1;
+			break;
+		case 'h':
+		case 'H':
+			len = strlen(optarg) > 255 ? 255 : strlen(optarg);
+			free(client_config.hostname);
+			client_config.hostname = xmalloc(len + 2);
+			client_config.hostname[OPT_CODE] = DHCP_HOST_NAME;
+			client_config.hostname[OPT_LEN] = len;
+			strncpy((char*)client_config.hostname + 2, optarg, len);
+			break;
+		case 'F':
+			len = strlen(optarg) > 255 ? 255 : strlen(optarg);
+			free(client_config.fqdn);
+			client_config.fqdn = xmalloc(len + 5);
+			client_config.fqdn[OPT_CODE] = DHCP_FQDN;
+			client_config.fqdn[OPT_LEN] = len + 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_LEN + 1] = 0x1;
+			client_config.fqdn[OPT_LEN + 2] = 0;
+			client_config.fqdn[OPT_LEN + 3] = 0;
+			strncpy((char*)client_config.fqdn + 5, optarg, len);
+			break;
+		case 'i':
+			client_config.interface =  optarg;
+			break;
+		case 'n':
+			client_config.abort_if_no_lease = 1;
+			break;
+		case 'p':
+			client_config.pidfile = optarg;
+			break;
+		case 'q':
+			client_config.quit_after_lease = 1;
+			break;
+		case 'r':
+			requested_ip = inet_addr(optarg);
+			break;
+		case 's':
+			client_config.script = optarg;
+			break;
+		case 'T':
+			client_config.timeout = atoi(optarg);
+			break;
+		case 't':
+			client_config.retries = atoi(optarg);
+			break;
+		case 'v':
+			printf("udhcpcd, version %s\n\n", VERSION);
+			return 0;
+			break;
+		default:
+			show_usage();
+		}
+	}
+
+	/* Start the log, sanitize fd's, and write a pid file */
+	start_log_and_pid("udhcpc", 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 = xmalloc(6 + 3);
+		client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
+		client_config.clientid[OPT_LEN] = 7;
+		client_config.clientid[OPT_DATA] = 1;
+		memcpy(client_config.clientid + 3, client_config.arp, 6);
+	}
+
+	if (!client_config.vendorclass) {
+		client_config.vendorclass = xmalloc(sizeof("udhcp "VERSION) + 2);
+		client_config.vendorclass[OPT_CODE] = DHCP_VENDOR;
+		client_config.vendorclass[OPT_LEN] = sizeof("udhcp "VERSION) - 1;
+		client_config.vendorclass[OPT_DATA] = 1;
+		memcpy(&client_config.vendorclass[OPT_DATA],
+			"udhcp "VERSION, sizeof("udhcp "VERSION) - 1);
+	}
+
+
+	/* setup the signal pipe */
+	udhcp_sp_setup();
+
+	state = INIT_SELECTING;
+	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);
+			if (fd < 0) {
+				LOG(LOG_ERR, "FATAL: couldn't listen on socket, %m");
+				return 0;
+			}
+		}
+		max_fd = udhcp_sp_fd_set(&rfds, fd);
+
+		if (tv.tv_sec > 0) {
+			DEBUG(LOG_INFO, "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 {
+					run_script(NULL, "leasefail");
+					if (client_config.background_if_no_lease) {
+						LOG(LOG_INFO, "No lease, forking to background.");
+						client_background();
+					} else if (client_config.abort_if_no_lease) {
+						LOG(LOG_INFO, "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) 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(LOG_INFO, "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(LOG_INFO, "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;
+					LOG(LOG_INFO, "Lease lost, entering init state");
+					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 = get_packet(&packet, fd);
+			else len = get_raw_packet(&packet, fd);
+
+			if (len == -1 && errno != EINTR) {
+				DEBUG(LOG_INFO, "error on read, %m, reopening socket");
+				change_mode(listen_mode); /* just close and reopen */
+			}
+			if (len < 0) continue;
+
+			if (packet.xid != xid) {
+				DEBUG(LOG_INFO, "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(LOG_INFO, "packet does not have our chaddr -- ignoring");
+				continue;
+			}
+
+			if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
+				DEBUG(LOG_ERR, "couldnt get option from packet -- ignoring");
+				continue;
+			}
+
+			switch (state) {
+			case INIT_SELECTING:
+				/* Must be a DHCPOFFER to one of our xid's */
+				if (*message == DHCPOFFER) {
+					if ((temp = get_option(&packet, DHCP_SERVER_ID))) {
+						memcpy(&server_addr, temp, 4);
+						xid = packet.xid;
+						requested_ip = packet.yiaddr;
+
+						/* enter requesting state */
+						state = REQUESTING;
+						timeout = now;
+						packet_num = 0;
+					} else {
+						DEBUG(LOG_ERR, "No server ID in message");
+					}
+				}
+				break;
+			case RENEW_REQUESTED:
+			case REQUESTING:
+			case RENEWING:
+			case REBINDING:
+				if (*message == DHCPACK) {
+					if (!(temp = get_option(&packet, DHCP_LEASE_TIME))) {
+						LOG(LOG_ERR, "No lease time with ACK, using 1 hour lease");
+						lease = 60 * 60;
+					} else {
+						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;
+					LOG(LOG_INFO, "Lease of %s obtained, lease time %ld",
+						inet_ntoa(temp_addr), lease);
+					start = now;
+					timeout = t1 + start;
+					requested_ip = packet.yiaddr;
+					run_script(&packet,
+						   ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
+
+					state = BOUND;
+					change_mode(LISTEN_NONE);
+					if (client_config.quit_after_lease)
+						return 0;
+					if (!client_config.foreground)
+						client_background();
+
+				} else if (*message == DHCPNAK) {
+					/* return to init state */
+					LOG(LOG_INFO, "Received DHCP NAK");
+					run_script(&packet, "nak");
+					if (state != REQUESTING)
+						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:
+				LOG(LOG_INFO, "Received SIGTERM");
+				return 0;
+			}
+		} else if (retval == -1 && errno == EINTR) {
+			/* a signal was caught */
+		} else {
+			/* An error occured */
+			DEBUG(LOG_ERR, "Error on select");
+		}
+
+	}
+	return 0;
+}