--- /dev/null
+/* 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;
+}
projects / oweals / busybox.git / commitdiff