| /* dhcpc.c |
| * |
| * udhcp DHCP client |
| * |
| * Russ Dill <Russ.Dill@asu.edu> July 2001 |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| #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 "dhcpd.h" |
| #include "dhcpc.h" |
| #include "options.h" |
| #include "clientpacket.h" |
| #include "script.h" |
| #include "socket.h" |
| #include "common.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; |
| |
| #ifdef CONFIG_INSTALL_NO_USR |
| #define DEFAULT_SCRIPT "/share/udhcpc/default.script" |
| #else |
| #define DEFAULT_SCRIPT "/usr/share/udhcpc/default.script" |
| #endif |
| |
| 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, |
| hostname: NULL, |
| ifindex: 0, |
| arp: "\0\0\0\0\0\0", /* appease gcc-3.0 */ |
| }; |
| |
| /* 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: |
| } |
| |
| /* 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; |
| } |
| |
| |
| int udhcpc_main(int argc, char *argv[]) |
| { |
| unsigned char *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; |
| time_t now; |
| int max_fd; |
| int sig; |
| |
| static const struct option arg_options[] = { |
| {"clientid", required_argument, 0, 'c'}, |
| {"foreground", no_argument, 0, 'f'}, |
| {"background", no_argument, 0, 'b'}, |
| {"hostname", required_argument, 0, 'H'}, |
| {"hostname", required_argument, 0, 'h'}, |
| {"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'}, |
| {"version", no_argument, 0, 'v'}, |
| {0, 0, 0, 0} |
| }; |
| |
| /* get options */ |
| while (1) { |
| int option_index = 0; |
| c = getopt_long(argc, argv, "c:fbH:h:i:np:qr:s:v", arg_options, &option_index); |
| if (c == -1) break; |
| |
| switch (c) { |
| case 'c': |
| len = strlen(optarg) > 255 ? 255 : strlen(optarg); |
| if (client_config.clientid) 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(client_config.clientid + 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); |
| if (client_config.hostname) 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(client_config.hostname + 2, 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 'v': |
| bb_error_msg("version %s\n", VERSION); |
| return(0); |
| break; |
| default: |
| bb_show_usage(); |
| } |
| } |
| |
| start_log("client"); |
| if (read_interface(client_config.interface, &client_config.ifindex, |
| NULL, client_config.arp) < 0) |
| return(1); |
| |
| if (!client_config.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); |
| } |
| |
| /* setup signal handlers */ |
| udhcp_set_signal_pipe(SIGUSR2); |
| |
| state = INIT_SELECTING; |
| run_script(NULL, "deconfig"); |
| change_mode(LISTEN_RAW); |
| |
| for (;;) { |
| |
| tv.tv_sec = timeout - time(0); |
| tv.tv_usec = 0; |
| FD_ZERO(&rfds); |
| |
| 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); |
| } |
| } |
| if (fd >= 0) FD_SET(fd, &rfds); |
| FD_SET(udhcp_signal_pipe[0], &rfds); |
| |
| if (tv.tv_sec > 0) { |
| DEBUG(LOG_INFO, "Waiting on select...\n"); |
| max_fd = udhcp_signal_pipe[0] > fd ? udhcp_signal_pipe[0] : fd; |
| retval = select(max_fd + 1, &rfds, NULL, NULL, &tv); |
| } else retval = 0; /* If we already timed out, fall through */ |
| |
| now = time(0); |
| if (retval == 0) { |
| /* timeout dropped to zero */ |
| switch (state) { |
| case INIT_SELECTING: |
| if (packet_num < 3) { |
| if (packet_num == 0) |
| xid = random_xid(); |
| |
| /* send discover packet */ |
| send_discover(xid, requested_ip); /* broadcast */ |
| |
| timeout = now + ((packet_num == 2) ? 4 : 2); |
| packet_num++; |
| } else { |
| 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 < 3) { |
| /* 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; |
| } |
| |
| 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 && FD_ISSET(udhcp_signal_pipe[0], &rfds)) { |
| if (read(udhcp_signal_pipe[0], &sig, sizeof(sig)) < 0) { |
| DEBUG(LOG_ERR, "Could not read signal: %m"); |
| continue; /* probably just EINTR */ |
| } |
| 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; |
| } |