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-rw-r--r--networking/udhcp/dhcpc.c646
1 files changed, 646 insertions, 0 deletions
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
new file mode 100644
index 0000000..2d48980
--- /dev/null
+++ b/networking/udhcp/dhcpc.c
@@ -0,0 +1,646 @@
+/* vi: set sw=4 ts=4: */
+/* 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 <syslog.h>
+
+/* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
+#define WANT_PIDFILE 1
+#include "common.h"
+#include "dhcpd.h"
+#include "dhcpc.h"
+#include "options.h"
+
+
+static int sockfd = -1;
+
+#define LISTEN_NONE 0
+#define LISTEN_KERNEL 1
+#define LISTEN_RAW 2
+static smallint listen_mode;
+
+#define INIT_SELECTING 0
+#define REQUESTING 1
+#define BOUND 2
+#define RENEWING 3
+#define REBINDING 4
+#define INIT_REBOOT 5
+#define RENEW_REQUESTED 6
+#define RELEASED 7
+static smallint state;
+
+/* struct client_config_t client_config is in bb_common_bufsiz1 */
+
+
+/* just a little helper */
+static void change_listen_mode(int new_mode)
+{
+ DEBUG("entering %s listen mode",
+ new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
+ if (sockfd >= 0) {
+ close(sockfd);
+ sockfd = -1;
+ }
+ listen_mode = new_mode;
+}
+
+
+/* perform a renew */
+static void perform_renew(void)
+{
+ bb_info_msg("Performing a DHCP renew");
+ switch (state) {
+ case BOUND:
+ change_listen_mode(LISTEN_KERNEL);
+ case RENEWING:
+ case REBINDING:
+ state = RENEW_REQUESTED;
+ break;
+ case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
+ udhcp_run_script(NULL, "deconfig");
+ case REQUESTING:
+ case RELEASED:
+ change_listen_mode(LISTEN_RAW);
+ state = INIT_SELECTING;
+ break;
+ case INIT_SELECTING:
+ break;
+ }
+}
+
+
+/* perform a release */
+static void perform_release(uint32_t requested_ip, uint32_t server_addr)
+{
+ char buffer[sizeof("255.255.255.255")];
+ struct in_addr temp_addr;
+
+ /* send release packet */
+ if (state == BOUND || state == RENEWING || state == REBINDING) {
+ temp_addr.s_addr = server_addr;
+ strcpy(buffer, inet_ntoa(temp_addr));
+ temp_addr.s_addr = requested_ip;
+ bb_info_msg("Unicasting a release of %s to %s",
+ inet_ntoa(temp_addr), buffer);
+ send_release(server_addr, requested_ip); /* unicast */
+ udhcp_run_script(NULL, "deconfig");
+ }
+ bb_info_msg("Entering released state");
+
+ change_listen_mode(LISTEN_NONE);
+ state = RELEASED;
+}
+
+
+#if BB_MMU
+static void client_background(void)
+{
+ bb_daemonize(0);
+ logmode &= ~LOGMODE_STDIO;
+ /* rewrite pidfile, as our pid is different now */
+ write_pidfile(client_config.pidfile);
+}
+#endif
+
+
+static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
+{
+ uint8_t *storage;
+ int len = strlen(str);
+ if (len > 255) len = 255;
+ storage = xzalloc(len + extra + OPT_DATA);
+ storage[OPT_CODE] = code;
+ storage[OPT_LEN] = len + extra;
+ memcpy(storage + extra + OPT_DATA, str, len);
+ return storage;
+}
+
+
+int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int udhcpc_main(int argc UNUSED_PARAM, char **argv)
+{
+ uint8_t *temp, *message;
+ char *str_c, *str_V, *str_h, *str_F, *str_r;
+ USE_FEATURE_UDHCP_PORT(char *str_P;)
+ llist_t *list_O = NULL;
+ int tryagain_timeout = 20;
+ int discover_timeout = 3;
+ int discover_retries = 3;
+ uint32_t server_addr = server_addr; /* for compiler */
+ uint32_t requested_ip = 0;
+ uint32_t xid = 0;
+ uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */
+ int packet_num;
+ int timeout; /* must be signed */
+ unsigned already_waited_sec;
+ unsigned opt;
+ int max_fd;
+ int retval;
+ struct timeval tv;
+ struct dhcpMessage packet;
+ fd_set rfds;
+
+#if ENABLE_GETOPT_LONG
+ static const char udhcpc_longopts[] ALIGN1 =
+ "clientid\0" Required_argument "c"
+ "clientid-none\0" No_argument "C"
+ "vendorclass\0" Required_argument "V"
+ "hostname\0" Required_argument "H"
+ "fqdn\0" Required_argument "F"
+ "interface\0" Required_argument "i"
+ "now\0" No_argument "n"
+ "pidfile\0" Required_argument "p"
+ "quit\0" No_argument "q"
+ "release\0" No_argument "R"
+ "request\0" Required_argument "r"
+ "script\0" Required_argument "s"
+ "timeout\0" Required_argument "T"
+ "version\0" No_argument "v"
+ "retries\0" Required_argument "t"
+ "tryagain\0" Required_argument "A"
+ "syslog\0" No_argument "S"
+ "request-option\0" Required_argument "O"
+ "no-default-options\0" No_argument "o"
+ "foreground\0" No_argument "f"
+ "background\0" No_argument "b"
+ USE_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
+ USE_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
+ ;
+#endif
+ enum {
+ OPT_c = 1 << 0,
+ OPT_C = 1 << 1,
+ OPT_V = 1 << 2,
+ OPT_H = 1 << 3,
+ OPT_h = 1 << 4,
+ OPT_F = 1 << 5,
+ OPT_i = 1 << 6,
+ OPT_n = 1 << 7,
+ OPT_p = 1 << 8,
+ OPT_q = 1 << 9,
+ OPT_R = 1 << 10,
+ OPT_r = 1 << 11,
+ OPT_s = 1 << 12,
+ OPT_T = 1 << 13,
+ OPT_t = 1 << 14,
+ OPT_v = 1 << 15,
+ OPT_S = 1 << 16,
+ OPT_A = 1 << 17,
+ OPT_O = 1 << 18,
+ OPT_o = 1 << 19,
+ OPT_f = 1 << 20,
+/* The rest has variable bit positions, need to be clever */
+ OPTBIT_f = 20,
+ USE_FOR_MMU( OPTBIT_b,)
+ USE_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
+ USE_FEATURE_UDHCP_PORT( OPTBIT_P,)
+ USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
+ USE_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
+ USE_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
+ };
+
+ /* Default options. */
+ USE_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
+ USE_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
+ client_config.interface = "eth0";
+ client_config.script = DEFAULT_SCRIPT;
+
+ /* Parse command line */
+ /* Cc: mutually exclusive; O: list; -T,-t,-A take numeric param */
+ opt_complementary = "c--C:C--c:O::T+:t+:A+";
+ USE_GETOPT_LONG(applet_long_options = udhcpc_longopts;)
+ opt = getopt32(argv, "c:CV:H:h:F:i:np:qRr:s:T:t:vSA:O:of"
+ USE_FOR_MMU("b")
+ USE_FEATURE_UDHCPC_ARPING("a")
+ USE_FEATURE_UDHCP_PORT("P:")
+ , &str_c, &str_V, &str_h, &str_h, &str_F
+ , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
+ , &client_config.script /* s */
+ , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
+ , &list_O
+ USE_FEATURE_UDHCP_PORT(, &str_P)
+ );
+ if (opt & OPT_c)
+ client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
+ if (opt & OPT_V)
+ client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
+ if (opt & (OPT_h|OPT_H))
+ client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
+ if (opt & OPT_F) {
+ client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 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<3>com<0> not "host.domain.com"
+ N: 1 => Client requests Server to not update DNS
+ */
+ client_config.fqdn[OPT_DATA + 0] = 0x1;
+ /* client_config.fqdn[OPT_DATA + 1] = 0; - redundant */
+ /* client_config.fqdn[OPT_DATA + 2] = 0; - redundant */
+ }
+ if (opt & OPT_r)
+ requested_ip = inet_addr(str_r);
+ if (opt & OPT_v) {
+ puts("version "BB_VER);
+ return 0;
+ }
+#if ENABLE_FEATURE_UDHCP_PORT
+ if (opt & OPT_P) {
+ CLIENT_PORT = xatou16(str_P);
+ SERVER_PORT = CLIENT_PORT - 1;
+ }
+#endif
+ if (opt & OPT_o)
+ client_config.no_default_options = 1;
+ while (list_O) {
+ char *optstr = llist_pop(&list_O);
+ int n = index_in_strings(dhcp_option_strings, optstr);
+ if (n < 0)
+ bb_error_msg_and_die("unknown option '%s'", optstr);
+ n = dhcp_options[n].code;
+ client_config.opt_mask[n >> 3] |= 1 << (n & 7);
+ }
+
+ if (udhcp_read_interface(client_config.interface, &client_config.ifindex,
+ NULL, client_config.arp))
+ return 1;
+#if !BB_MMU
+ /* on NOMMU reexec (i.e., background) early */
+ if (!(opt & OPT_f)) {
+ bb_daemonize_or_rexec(0 /* flags */, argv);
+ logmode = 0;
+ }
+#endif
+ if (opt & OPT_S) {
+ openlog(applet_name, LOG_PID, LOG_LOCAL0);
+ logmode |= LOGMODE_SYSLOG;
+ }
+
+ /* Make sure fd 0,1,2 are open */
+ bb_sanitize_stdio();
+ /* Equivalent of doing a fflush after every \n */
+ setlinebuf(stdout);
+
+ /* Create pidfile */
+ write_pidfile(client_config.pidfile);
+
+ /* Goes to stdout (unless NOMMU) and possibly syslog */
+ bb_info_msg("%s (v"BB_VER") started", applet_name);
+
+ /* if not set, and not suppressed, setup the default client ID */
+ if (!client_config.clientid && !(opt & OPT_C)) {
+ client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
+ client_config.clientid[OPT_DATA] = 1;
+ memcpy(client_config.clientid + OPT_DATA+1, client_config.arp, 6);
+ }
+
+ if (!client_config.vendorclass)
+ client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0);
+
+ /* setup the signal pipe */
+ udhcp_sp_setup();
+
+ state = INIT_SELECTING;
+ udhcp_run_script(NULL, "deconfig");
+ change_listen_mode(LISTEN_RAW);
+ packet_num = 0;
+ timeout = 0;
+ already_waited_sec = 0;
+
+ /* Main event loop. select() waits on signal pipe and possibly
+ * on sockfd.
+ * "continue" statements in code below jump to the top of the loop.
+ */
+ for (;;) {
+ unsigned timestamp_before_wait;
+
+ if (listen_mode != LISTEN_NONE && sockfd < 0) {
+ if (listen_mode == LISTEN_KERNEL)
+ sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
+ else
+ sockfd = udhcp_raw_socket(client_config.ifindex);
+ }
+ max_fd = udhcp_sp_fd_set(&rfds, sockfd);
+
+ tv.tv_sec = timeout - already_waited_sec;
+ tv.tv_usec = 0;
+ retval = 0; /* If we already timed out, fall through, else... */
+ if (tv.tv_sec > 0) {
+ timestamp_before_wait = (unsigned)monotonic_sec();
+ DEBUG("Waiting on select...");
+ retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
+ if (retval < 0) {
+ /* EINTR? A signal was caught, don't panic */
+ if (errno == EINTR)
+ continue;
+ /* Else: an error occured, panic! */
+ bb_perror_msg_and_die("select");
+ }
+ }
+
+ /* If timeout dropped to zero, time to become active:
+ * resend discover/renew/whatever
+ */
+ if (retval == 0) {
+ /* We will restart the wait in any case */
+ already_waited_sec = 0;
+
+ switch (state) {
+ case INIT_SELECTING:
+ if (packet_num < discover_retries) {
+ if (packet_num == 0)
+ xid = random_xid();
+
+ send_discover(xid, requested_ip); /* broadcast */
+
+ timeout = discover_timeout;
+ packet_num++;
+ continue;
+ }
+ leasefail:
+ udhcp_run_script(NULL, "leasefail");
+#if BB_MMU /* -b is not supported on NOMMU */
+ if (opt & OPT_b) { /* background if no lease */
+ bb_info_msg("No lease, forking to background");
+ client_background();
+ /* do not background again! */
+ opt = ((opt & ~OPT_b) | OPT_f);
+ } else
+#endif
+ if (opt & OPT_n) { /* abort if no lease */
+ bb_info_msg("No lease, failing");
+ retval = 1;
+ goto ret;
+ }
+ /* wait before trying again */
+ timeout = tryagain_timeout;
+ packet_num = 0;
+ continue;
+ case RENEW_REQUESTED:
+ case REQUESTING:
+ if (packet_num < discover_retries) {
+ /* send request packet */
+ if (state == RENEW_REQUESTED) /* unicast */
+ send_renew(xid, server_addr, requested_ip);
+ else /* broadcast */
+ send_select(xid, server_addr, requested_ip);
+
+ timeout = discover_timeout;
+ packet_num++;
+ continue;
+ }
+ /* timed out, go back to init state */
+ if (state == RENEW_REQUESTED)
+ udhcp_run_script(NULL, "deconfig");
+ change_listen_mode(LISTEN_RAW);
+ /* "discover...select...discover..." loops
+ * were seen in the wild. Treat them similarly
+ * to "no response to discover" case */
+ if (state == REQUESTING) {
+ state = INIT_SELECTING;
+ goto leasefail;
+ }
+ state = INIT_SELECTING;
+ timeout = 0;
+ packet_num = 0;
+ continue;
+ case BOUND:
+ /* Half of the lease passed, time to enter renewing state */
+ change_listen_mode(LISTEN_KERNEL);
+ DEBUG("Entering renew state");
+ state = RENEWING;
+ /* fall right through */
+ case RENEWING:
+ if (timeout > 60) {
+ /* send a request packet */
+ send_renew(xid, server_addr, requested_ip); /* unicast */
+ timeout >>= 1;
+ continue;
+ }
+ /* Timed out, enter rebinding state */
+ DEBUG("Entering rebinding state");
+ state = REBINDING;
+ /* fall right through */
+ case REBINDING:
+ /* Lease is *really* about to run out,
+ * try to find DHCP server using broadcast */
+ if (timeout > 0) {
+ /* send a request packet */
+ send_renew(xid, 0 /* INADDR_ANY*/, requested_ip); /* broadcast */
+ timeout >>= 1;
+ continue;
+ }
+ /* Timed out, enter init state */
+ bb_info_msg("Lease lost, entering init state");
+ udhcp_run_script(NULL, "deconfig");
+ change_listen_mode(LISTEN_RAW);
+ state = INIT_SELECTING;
+ /*timeout = 0; - already is */
+ packet_num = 0;
+ continue;
+ /* case RELEASED: */
+ }
+ /* yah, I know, *you* say it would never happen */
+ timeout = INT_MAX;
+ continue; /* back to main loop */
+ }
+
+ /* select() didn't timeout, something did happen. */
+ /* Is it a packet? */
+ if (listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) {
+ int len;
+ /* A packet is ready, read it */
+
+ if (listen_mode == LISTEN_KERNEL)
+ len = udhcp_recv_kernel_packet(&packet, sockfd);
+ else
+ len = udhcp_recv_raw_packet(&packet, sockfd);
+ if (len == -1) { /* error is severe, reopen socket */
+ DEBUG("error on read, %s, reopening socket", strerror(errno));
+ sleep(discover_timeout); /* 3 seconds by default */
+ change_listen_mode(listen_mode); /* just close and reopen */
+ }
+ /* If this packet will turn out to be unrelated/bogus,
+ * we will go back and wait for next one.
+ * Be sure timeout is properly decreased. */
+ already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
+ if (len < 0)
+ continue;
+
+ if (packet.xid != xid) {
+ DEBUG("Ignoring xid %x (our xid is %x)",
+ (unsigned)packet.xid, (unsigned)xid);
+ continue;
+ }
+
+ /* Ignore packets that aren't for us */
+ if (memcmp(packet.chaddr, client_config.arp, 6)) {
+ DEBUG("Packet does not have our chaddr - ignoring");
+ continue;
+ }
+
+ message = get_option(&packet, DHCP_MESSAGE_TYPE);
+ if (message == NULL) {
+ bb_error_msg("cannot get message type from packet - ignoring");
+ continue;
+ }
+
+ switch (state) {
+ case INIT_SELECTING:
+ /* Must be a DHCPOFFER to one of our xid's */
+ if (*message == DHCPOFFER) {
+ /* TODO: why we don't just fetch server's IP from IP header? */
+ temp = get_option(&packet, DHCP_SERVER_ID);
+ if (!temp) {
+ bb_error_msg("no server ID in message");
+ continue;
+ /* still selecting - this server looks bad */
+ }
+ /* it IS unaligned sometimes, don't "optimize" */
+ server_addr = get_unaligned_u32p((uint32_t*)temp);
+ xid = packet.xid;
+ requested_ip = packet.yiaddr;
+
+ /* enter requesting state */
+ state = REQUESTING;
+ timeout = 0;
+ packet_num = 0;
+ already_waited_sec = 0;
+ }
+ continue;
+ case RENEW_REQUESTED:
+ case REQUESTING:
+ case RENEWING:
+ case REBINDING:
+ if (*message == DHCPACK) {
+ temp = get_option(&packet, DHCP_LEASE_TIME);
+ if (!temp) {
+ bb_error_msg("no lease time with ACK, using 1 hour lease");
+ lease_seconds = 60 * 60;
+ } else {
+ /* it IS unaligned sometimes, don't "optimize" */
+ lease_seconds = get_unaligned_u32p((uint32_t*)temp);
+ lease_seconds = ntohl(lease_seconds);
+ lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
+ if (lease_seconds < 10) /* and not too small */
+ lease_seconds = 10;
+ }
+#if ENABLE_FEATURE_UDHCPC_ARPING
+ if (opt & OPT_a) {
+/* RFC 2131 3.1 paragraph 5:
+ * "The client receives the DHCPACK message with configuration
+ * parameters. The client SHOULD perform a final check on the
+ * parameters (e.g., ARP for allocated network address), and notes
+ * the duration of the lease specified in the DHCPACK message. At this
+ * point, the client is configured. If the client detects that the
+ * address is already in use (e.g., through the use of ARP),
+ * the client MUST send a DHCPDECLINE message to the server and restarts
+ * the configuration process..." */
+ if (!arpping(packet.yiaddr,
+ (uint32_t) 0,
+ client_config.arp,
+ client_config.interface)
+ ) {
+ bb_info_msg("offered address is in use "
+ "(got ARP reply), declining");
+ send_decline(xid, server_addr, packet.yiaddr);
+
+ if (state != REQUESTING)
+ udhcp_run_script(NULL, "deconfig");
+ change_listen_mode(LISTEN_RAW);
+ state = INIT_SELECTING;
+ requested_ip = 0;
+ timeout = tryagain_timeout;
+ packet_num = 0;
+ already_waited_sec = 0;
+ continue; /* back to main loop */
+ }
+ }
+#endif
+ /* enter bound state */
+ timeout = lease_seconds / 2;
+ {
+ struct in_addr temp_addr;
+ temp_addr.s_addr = packet.yiaddr;
+ bb_info_msg("Lease of %s obtained, lease time %u",
+ inet_ntoa(temp_addr), (unsigned)lease_seconds);
+ }
+ requested_ip = packet.yiaddr;
+ udhcp_run_script(&packet,
+ ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
+
+ state = BOUND;
+ change_listen_mode(LISTEN_NONE);
+ if (opt & OPT_q) { /* quit after lease */
+ if (opt & OPT_R) /* release on quit */
+ perform_release(requested_ip, server_addr);
+ goto ret0;
+ }
+#if BB_MMU /* NOMMU case backgrounded earlier */
+ if (!(opt & OPT_f)) {
+ client_background();
+ /* do not background again! */
+ opt = ((opt & ~OPT_b) | OPT_f);
+ }
+#endif
+ already_waited_sec = 0;
+ continue; /* back to main loop */
+ }
+ 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");
+ change_listen_mode(LISTEN_RAW);
+ sleep(3); /* avoid excessive network traffic */
+ state = INIT_SELECTING;
+ requested_ip = 0;
+ timeout = 0;
+ packet_num = 0;
+ already_waited_sec = 0;
+ }
+ continue;
+ /* case BOUND, RELEASED: - ignore all packets */
+ }
+ continue; /* back to main loop */
+ }
+
+ /* select() didn't timeout, something did happen.
+ * But it wasn't a packet. It's a signal pipe then. */
+ {
+ int signo = udhcp_sp_read(&rfds);
+ switch (signo) {
+ case SIGUSR1:
+ perform_renew();
+ /* start things over */
+ packet_num = 0;
+ /* Kill any timeouts because the user wants this to hurry along */
+ timeout = 0;
+ break;
+ case SIGUSR2:
+ perform_release(requested_ip, server_addr);
+ timeout = INT_MAX;
+ break;
+ case SIGTERM:
+ bb_info_msg("Received SIGTERM");
+ if (opt & OPT_R) /* release on quit */
+ perform_release(requested_ip, server_addr);
+ goto ret0;
+ }
+ }
+ } /* for (;;) - main loop ends */
+
+ ret0:
+ retval = 0;
+ ret:
+ /*if (client_config.pidfile) - remove_pidfile has its own check */
+ remove_pidfile(client_config.pidfile);
+ return retval;
+}