mirror of
https://github.com/sheumann/hush.git
synced 2024-08-15 02:29:00 +00:00
552 lines
15 KiB
C
552 lines
15 KiB
C
/* 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 "clientsocket.h"
|
|
#include "script.h"
|
|
#include "socket.h"
|
|
#include "common.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,
|
|
.hostname = NULL,
|
|
.fqdn = NULL,
|
|
.ifindex = 0,
|
|
.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\n"
|
|
" -C, --clientid-none Suppress default client 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"
|
|
" -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'},
|
|
{"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'},
|
|
{"version", no_argument, 0, 'v'},
|
|
{0, 0, 0, 0}
|
|
};
|
|
|
|
/* get options */
|
|
while (1) {
|
|
int option_index = 0;
|
|
c = getopt_long(argc, argv, "c:CfbH:h:F:i:np:qr:s: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);
|
|
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 'C':
|
|
if (client_config.clientid) show_usage();
|
|
no_clientid = 1;
|
|
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 'F':
|
|
len = strlen(optarg) > 255 ? 255 : strlen(optarg);
|
|
if (client_config.fqdn) 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(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 '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);
|
|
}
|
|
|
|
/* 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 < 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 {
|
|
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 < 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;
|
|
}
|
|
/* 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;
|
|
}
|