fe7cd642b0
(add/remove: 0/0 grow/shrink: 12/131 up/down: 91/-727) Total: -636 bytes text data bss dec hex filename 773469 1058 11092 785619 bfcd3 busybox_old 772644 1058 11092 784794 bf99a busybox_unstripped
553 lines
15 KiB
C
553 lines
15 KiB
C
/* vi: set sw=4 ts=4: */
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/* dhcpc.c
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*
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* udhcp DHCP client
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*
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* Russ Dill <Russ.Dill@asu.edu> July 2001
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*
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* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
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*/
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#include <getopt.h>
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#include <syslog.h>
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/* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
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#define WANT_PIDFILE 1
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#include "common.h"
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#include "dhcpd.h"
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#include "dhcpc.h"
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#include "options.h"
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/* Something is definitely wrong here. IPv4 addresses
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* in variables of type long?? BTW, we use inet_ntoa()
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* in the code. Manpage says that struct in_addr has a member of type long (!)
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* which holds IPv4 address, and the struct is passed by value (!!)
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*/
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static unsigned timeout;
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static uint32_t requested_ip; /* = 0 */
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static uint32_t server_addr;
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static int packet_num; /* = 0 */
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static int sockfd = -1;
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#define LISTEN_NONE 0
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#define LISTEN_KERNEL 1
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#define LISTEN_RAW 2
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static smallint listen_mode;
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static smallint state;
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struct client_config_t client_config;
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/* just a little helper */
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static void change_mode(int new_mode)
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{
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DEBUG("entering %s listen mode",
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new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
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if (sockfd >= 0) {
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close(sockfd);
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sockfd = -1;
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}
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listen_mode = new_mode;
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}
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/* perform a renew */
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static void perform_renew(void)
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{
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bb_info_msg("Performing a DHCP renew");
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switch (state) {
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case BOUND:
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change_mode(LISTEN_KERNEL);
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case RENEWING:
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case REBINDING:
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state = RENEW_REQUESTED;
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break;
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case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
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udhcp_run_script(NULL, "deconfig");
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case REQUESTING:
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case RELEASED:
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change_mode(LISTEN_RAW);
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state = INIT_SELECTING;
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break;
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case INIT_SELECTING:
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break;
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}
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/* start things over */
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packet_num = 0;
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/* Kill any timeouts because the user wants this to hurry along */
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timeout = 0;
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}
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/* perform a release */
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static void perform_release(void)
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{
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char buffer[sizeof("255.255.255.255")];
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struct in_addr temp_addr;
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/* send release packet */
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if (state == BOUND || state == RENEWING || state == REBINDING) {
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temp_addr.s_addr = server_addr;
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strcpy(buffer, inet_ntoa(temp_addr));
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temp_addr.s_addr = requested_ip;
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bb_info_msg("Unicasting a release of %s to %s",
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inet_ntoa(temp_addr), buffer);
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send_release(server_addr, requested_ip); /* unicast */
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udhcp_run_script(NULL, "deconfig");
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}
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bb_info_msg("Entering released state");
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change_mode(LISTEN_NONE);
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state = RELEASED;
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timeout = INT_MAX;
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}
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static void client_background(void)
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{
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#if !BB_MMU
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bb_error_msg("cannot background in uclinux (yet)");
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/* ... mainly because udhcpc calls client_background()
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* in _the _middle _of _udhcpc _run_, not at the start!
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* If that will be properly disabled for NOMMU, client_background()
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* will work on NOMMU too */
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#else
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bb_daemonize(0);
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logmode &= ~LOGMODE_STDIO;
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/* rewrite pidfile, as our pid is different now */
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write_pidfile(client_config.pidfile);
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#endif
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/* Do not fork again. */
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client_config.foreground = 1;
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client_config.background_if_no_lease = 0;
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}
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static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
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{
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uint8_t *storage;
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int len = strlen(str);
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if (len > 255) len = 255;
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storage = xzalloc(len + extra + OPT_DATA);
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storage[OPT_CODE] = code;
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storage[OPT_LEN] = len + extra;
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memcpy(storage + extra + OPT_DATA, str, len);
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return storage;
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}
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int udhcpc_main(int argc, char **argv);
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int udhcpc_main(int argc, char **argv)
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{
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uint8_t *temp, *message;
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char *str_c, *str_V, *str_h, *str_F, *str_r, *str_T, *str_t;
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uint32_t xid = 0;
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uint32_t lease = 0; /* can be given as 32-bit quantity */
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unsigned t1 = 0, t2 = 0; /* what a wonderful names */
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unsigned start = 0;
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unsigned now;
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unsigned opt;
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int max_fd;
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int retval;
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int len;
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struct timeval tv;
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struct in_addr temp_addr;
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struct dhcpMessage packet;
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fd_set rfds;
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enum {
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OPT_c = 1 << 0,
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OPT_C = 1 << 1,
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OPT_V = 1 << 2,
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OPT_f = 1 << 3,
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OPT_b = 1 << 4,
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OPT_H = 1 << 5,
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OPT_h = 1 << 6,
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OPT_F = 1 << 7,
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OPT_i = 1 << 8,
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OPT_n = 1 << 9,
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OPT_p = 1 << 10,
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OPT_q = 1 << 11,
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OPT_R = 1 << 12,
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OPT_r = 1 << 13,
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OPT_s = 1 << 14,
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OPT_T = 1 << 15,
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OPT_t = 1 << 16,
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OPT_v = 1 << 17,
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OPT_S = 1 << 18,
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};
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#if ENABLE_GETOPT_LONG
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static const char udhcpc_longopts[] ALIGN1 =
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"clientid\0" Required_argument "c"
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"clientid-none\0" No_argument "C"
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"vendorclass\0" Required_argument "V"
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"foreground\0" No_argument "f"
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"background\0" No_argument "b"
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"hostname\0" Required_argument "H"
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"hostname\0" Required_argument "h"
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"fqdn\0" Required_argument "F"
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"interface\0" Required_argument "i"
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"now\0" No_argument "n"
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"pidfile\0" Required_argument "p"
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"quit\0" No_argument "q"
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"release\0" No_argument "R"
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"request\0" Required_argument "r"
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"script\0" Required_argument "s"
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"timeout\0" Required_argument "T"
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"version\0" No_argument "v"
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"retries\0" Required_argument "t"
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"syslog\0" No_argument "S"
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;
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#endif
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/* Default options. */
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client_config.interface = "eth0";
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client_config.script = DEFAULT_SCRIPT;
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client_config.retries = 3;
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client_config.timeout = 3;
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/* Parse command line */
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opt_complementary = "c--C:C--c" // mutually exclusive
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":hH:Hh"; // -h and -H are the same
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#if ENABLE_GETOPT_LONG
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applet_long_options = udhcpc_longopts;
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#endif
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opt = getopt32(argv, "c:CV:fbH:h:F:i:np:qRr:s:T:t:vS",
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&str_c, &str_V, &str_h, &str_h, &str_F,
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&client_config.interface, &client_config.pidfile, &str_r,
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&client_config.script, &str_T, &str_t
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);
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if (opt & OPT_c)
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client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
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//if (opt & OPT_C)
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if (opt & OPT_V)
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client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
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if (opt & OPT_f)
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client_config.foreground = 1;
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if (opt & OPT_b)
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client_config.background_if_no_lease = 1;
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if (opt & OPT_h)
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client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
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if (opt & OPT_F) {
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client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
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/* Flags: 0000NEOS
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S: 1 => Client requests Server to update A RR in DNS as well as PTR
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O: 1 => Server indicates to client that DNS has been updated regardless
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E: 1 => Name data is DNS format, i.e. <4>host<6>domain<4>com<0> not "host.domain.com"
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N: 1 => Client requests Server to not update DNS
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*/
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client_config.fqdn[OPT_DATA + 0] = 0x1;
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/* client_config.fqdn[OPT_DATA + 1] = 0; - redundant */
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/* client_config.fqdn[OPT_DATA + 2] = 0; - redundant */
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}
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// if (opt & OPT_i) client_config.interface = ...
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if (opt & OPT_n)
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client_config.abort_if_no_lease = 1;
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// if (opt & OPT_p) client_config.pidfile = ...
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if (opt & OPT_q)
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client_config.quit_after_lease = 1;
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if (opt & OPT_R)
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client_config.release_on_quit = 1;
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if (opt & OPT_r)
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requested_ip = inet_addr(str_r);
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// if (opt & OPT_s) client_config.script = ...
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if (opt & OPT_T)
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client_config.timeout = xatoi_u(str_T);
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if (opt & OPT_t)
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client_config.retries = xatoi_u(str_t);
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if (opt & OPT_v) {
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printf("version %s\n", BB_VER);
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return 0;
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}
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if (opt & OPT_S) {
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openlog(applet_name, LOG_PID, LOG_LOCAL0);
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logmode |= LOGMODE_SYSLOG;
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}
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if (read_interface(client_config.interface, &client_config.ifindex,
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NULL, client_config.arp))
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return 1;
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/* Make sure fd 0,1,2 are open */
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bb_sanitize_stdio();
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/* Equivalent of doing a fflush after every \n */
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setlinebuf(stdout);
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/* Create pidfile */
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write_pidfile(client_config.pidfile);
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/* if (!..) bb_perror_msg("cannot create pidfile %s", pidfile); */
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/* Goes to stdout and possibly syslog */
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bb_info_msg("%s (v%s) started", applet_name, BB_VER);
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/* if not set, and not suppressed, setup the default client ID */
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if (!client_config.clientid && !(opt & OPT_C)) {
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client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
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client_config.clientid[OPT_DATA] = 1;
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memcpy(client_config.clientid + OPT_DATA+1, client_config.arp, 6);
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}
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if (!client_config.vendorclass)
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client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0);
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/* setup the signal pipe */
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udhcp_sp_setup();
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state = INIT_SELECTING;
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udhcp_run_script(NULL, "deconfig");
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change_mode(LISTEN_RAW);
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tv.tv_sec = 0;
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goto jump_in;
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for (;;) {
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tv.tv_sec = timeout - monotonic_sec();
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jump_in:
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tv.tv_usec = 0;
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if (listen_mode != LISTEN_NONE && sockfd < 0) {
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if (listen_mode == LISTEN_KERNEL)
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sockfd = listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
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else
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sockfd = raw_socket(client_config.ifindex);
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}
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max_fd = udhcp_sp_fd_set(&rfds, sockfd);
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retval = 0; /* If we already timed out, fall through, else... */
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if (tv.tv_sec > 0) {
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DEBUG("Waiting on select...");
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retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
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}
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now = monotonic_sec();
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if (retval < 0) {
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/* EINTR? signal was caught, don't panic */
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if (errno != EINTR) {
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/* Else: an error occured, panic! */
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bb_perror_msg_and_die("select");
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}
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} else if (retval == 0) {
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/* timeout dropped to zero */
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switch (state) {
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case INIT_SELECTING:
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if (packet_num < client_config.retries) {
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if (packet_num == 0)
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xid = random_xid();
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/* send discover packet */
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send_discover(xid, requested_ip); /* broadcast */
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timeout = now + client_config.timeout;
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packet_num++;
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} else {
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udhcp_run_script(NULL, "leasefail");
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if (client_config.background_if_no_lease) {
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bb_info_msg("No lease, forking to background");
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client_background();
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} else if (client_config.abort_if_no_lease) {
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bb_info_msg("No lease, failing");
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retval = 1;
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goto ret;
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}
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/* wait to try again */
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packet_num = 0;
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timeout = now + 60;
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}
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break;
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case RENEW_REQUESTED:
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case REQUESTING:
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if (packet_num < client_config.retries) {
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/* send request packet */
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if (state == RENEW_REQUESTED)
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send_renew(xid, server_addr, requested_ip); /* unicast */
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else send_selecting(xid, server_addr, requested_ip); /* broadcast */
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timeout = now + ((packet_num == 2) ? 10 : 2);
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packet_num++;
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} else {
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/* timed out, go back to init state */
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if (state == RENEW_REQUESTED)
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udhcp_run_script(NULL, "deconfig");
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state = INIT_SELECTING;
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timeout = now;
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packet_num = 0;
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change_mode(LISTEN_RAW);
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}
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break;
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case BOUND:
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/* Lease is starting to run out, time to enter renewing state */
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state = RENEWING;
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change_mode(LISTEN_KERNEL);
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DEBUG("Entering renew state");
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/* fall right through */
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case RENEWING:
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/* Either set a new T1, or enter REBINDING state */
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if ((t2 - t1) <= (lease / 14400 + 1)) {
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/* timed out, enter rebinding state */
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state = REBINDING;
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timeout = now + (t2 - t1);
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DEBUG("Entering rebinding state");
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} else {
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/* send a request packet */
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send_renew(xid, server_addr, requested_ip); /* unicast */
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t1 = (t2 - t1) / 2 + t1;
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timeout = start + t1;
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}
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break;
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case REBINDING:
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/* Either set a new T2, or enter INIT state */
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if ((lease - t2) <= (lease / 14400 + 1)) {
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/* timed out, enter init state */
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state = INIT_SELECTING;
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bb_info_msg("Lease lost, entering init state");
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udhcp_run_script(NULL, "deconfig");
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timeout = now;
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packet_num = 0;
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change_mode(LISTEN_RAW);
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} else {
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/* send a request packet */
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send_renew(xid, 0, requested_ip); /* broadcast */
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t2 = (lease - t2) / 2 + t2;
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timeout = start + t2;
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}
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break;
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case RELEASED:
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/* yah, I know, *you* say it would never happen */
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timeout = INT_MAX;
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break;
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}
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} else if (listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) {
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/* a packet is ready, read it */
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if (listen_mode == LISTEN_KERNEL)
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len = udhcp_get_packet(&packet, sockfd);
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else len = get_raw_packet(&packet, sockfd);
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if (len == -1 && errno != EINTR) {
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DEBUG("error on read, %s, reopening socket", strerror(errno));
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change_mode(listen_mode); /* just close and reopen */
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}
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if (len < 0) continue;
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if (packet.xid != xid) {
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DEBUG("Ignoring XID %x (our xid is %x)",
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(unsigned)packet.xid, (unsigned)xid);
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continue;
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}
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/* Ignore packets that aren't for us */
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if (memcmp(packet.chaddr, client_config.arp, 6)) {
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DEBUG("Packet does not have our chaddr - ignoring");
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continue;
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}
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message = get_option(&packet, DHCP_MESSAGE_TYPE);
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if (message == NULL) {
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bb_error_msg("cannot get option from packet - ignoring");
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continue;
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}
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switch (state) {
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case INIT_SELECTING:
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/* Must be a DHCPOFFER to one of our xid's */
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if (*message == DHCPOFFER) {
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temp = get_option(&packet, DHCP_SERVER_ID);
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if (temp) {
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/* can be misaligned, thus memcpy */
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memcpy(&server_addr, temp, 4);
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xid = packet.xid;
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requested_ip = packet.yiaddr;
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/* enter requesting state */
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state = REQUESTING;
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timeout = now;
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packet_num = 0;
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} else {
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bb_error_msg("no server ID in message");
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}
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}
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break;
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case RENEW_REQUESTED:
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case REQUESTING:
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case RENEWING:
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case REBINDING:
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if (*message == DHCPACK) {
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temp = get_option(&packet, DHCP_LEASE_TIME);
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if (!temp) {
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bb_error_msg("no lease time with ACK, using 1 hour lease");
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lease = 60 * 60;
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} else {
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/* can be misaligned, thus memcpy */
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memcpy(&lease, temp, 4);
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lease = ntohl(lease);
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}
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/* enter bound state */
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t1 = lease / 2;
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/* little fixed point for n * .875 */
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t2 = (lease * 7) >> 3;
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temp_addr.s_addr = packet.yiaddr;
|
|
bb_info_msg("Lease of %s obtained, lease time %u",
|
|
inet_ntoa(temp_addr), (unsigned)lease);
|
|
start = now;
|
|
timeout = start + t1;
|
|
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();
|
|
goto ret0;
|
|
}
|
|
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 {
|
|
int signo = udhcp_sp_read(&rfds);
|
|
switch (signo) {
|
|
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();
|
|
goto ret0;
|
|
}
|
|
}
|
|
} /* for (;;) */
|
|
ret0:
|
|
retval = 0;
|
|
ret:
|
|
/*if (client_config.pidfile) - remove_pidfile has it's own check */
|
|
remove_pidfile(client_config.pidfile);
|
|
return retval;
|
|
}
|