hwclock: fix sizeof bug (used it on pointer, not array); make --systohc exact
[oweals/busybox.git] / networking / udhcp / dhcpc.c
index 115cddbf0fbfbc9f2f996680cb441f5951011667..9a2fe35e4d169e0b03047cef61e441d4ea4f46c9 100644 (file)
@@ -7,9 +7,7 @@
  *
  * 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"
 
 static int sockfd = -1;
 
-#define LISTEN_NONE 0
+#define LISTEN_NONE   0
 #define LISTEN_KERNEL 1
-#define LISTEN_RAW 2
+#define LISTEN_RAW    2
 static smallint listen_mode;
 
+/* initial state: (re)start DHCP negotiation */
 #define INIT_SELECTING  0
+/* discover was sent, DHCPOFFER reply received */
 #define REQUESTING      1
+/* select/renew was sent, DHCPACK reply received */
 #define BOUND           2
+/* half of lease passed, want to renew it by sending unicast renew requests */
 #define RENEWING        3
+/* renew requests were not answered, lease is almost over, send broadcast renew */
 #define REBINDING       4
-#define INIT_REBOOT     5
-#define RENEW_REQUESTED 6
-#define RELEASED        7
+/* manually requested renew (SIGUSR1) */
+#define RENEW_REQUESTED 5
+/* release, possibly manually requested (SIGUSR2) */
+#define RELEASED        6
 static smallint state;
 
 /* struct client_config_t client_config is in bb_common_bufsiz1 */
@@ -41,8 +45,11 @@ static smallint state;
 /* 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");
+       log1("Entering listen mode: %s",
+               new_mode != LISTEN_NONE
+                       ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
+                       : "none"
+       );
 
        listen_mode = new_mode;
        if (sockfd >= 0) {
@@ -133,7 +140,7 @@ 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;)
+       IF_FEATURE_UDHCP_PORT(char *str_P;)
        llist_t *list_O = NULL;
        int tryagain_timeout = 20;
        int discover_timeout = 3;
@@ -149,10 +156,10 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
        int max_fd;
        int retval;
        struct timeval tv;
-       struct dhcpMessage packet;
+       struct dhcp_packet packet;
        fd_set rfds;
 
-#if ENABLE_GETOPT_LONG
+#if ENABLE_LONG_OPTS
        static const char udhcpc_longopts[] ALIGN1 =
                "clientid\0"       Required_argument "c"
                "clientid-none\0"  No_argument       "C"
@@ -175,8 +182,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                "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")
+               IF_FEATURE_UDHCPC_ARPING("arping\0"     No_argument       "a")
+               IF_FEATURE_UDHCP_PORT("client-port\0"   Required_argument "P")
                ;
 #endif
        enum {
@@ -195,42 +202,49 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                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,
+               OPT_S = 1 << 15,
+               OPT_A = 1 << 16,
+               OPT_O = 1 << 17,
+               OPT_o = 1 << 18,
+               OPT_f = 1 << 19,
 /* 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,)
+               OPTBIT_f = 19,
+               USE_FOR_MMU(             OPTBIT_b,)
+               IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
+               IF_FEATURE_UDHCP_PORT(   OPTBIT_P,)
+               USE_FOR_MMU(             OPT_b = 1 << OPTBIT_b,)
+               IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
+               IF_FEATURE_UDHCP_PORT(   OPT_P = 1 << OPTBIT_P,)
        };
 
        /* Default options. */
-       USE_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
-       USE_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
+       IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
+       IF_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"
+       opt_complementary = "c--C:C--c:O::T+:t+:A+"
+#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
+               ":vv"
+#endif
+               ;
+       IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
+       opt = getopt32(argv, "c:CV:H:h:F:i:np:qRr:s:T:t:SA:O:of"
                USE_FOR_MMU("b")
-               USE_FEATURE_UDHCPC_ARPING("a")
-               USE_FEATURE_UDHCP_PORT("P:")
+               IF_FEATURE_UDHCPC_ARPING("a")
+               IF_FEATURE_UDHCP_PORT("P:")
+               "v"
                , &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_FEATURE_UDHCP_PORT(, &str_P)
+#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
+               , &dhcp_verbose
+#endif
                );
        if (opt & OPT_c)
                client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
@@ -252,10 +266,6 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
        }
        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);
@@ -273,18 +283,23 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                client_config.opt_mask[n >> 3] |= 1 << (n & 7);
        }
 
-       if (udhcp_read_interface(client_config.interface, &client_config.ifindex,
-                          NULL, client_config.arp))
+       if (udhcp_read_interface(client_config.interface,
+                       &client_config.ifindex,
+                       NULL,
+                       client_config.client_mac)
+       ) {
                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;
+               logmode = LOGMODE_NONE;
        }
 #endif
        if (opt & OPT_S) {
-               openlog(applet_name, LOG_PID, LOG_LOCAL0);
+               openlog(applet_name, LOG_PID, LOG_DAEMON);
                logmode |= LOGMODE_SYSLOG;
        }
 
@@ -299,17 +314,17 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
        /* 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 not set, and not suppressed, set up 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);
+               memcpy(client_config.clientid + OPT_DATA+1, client_config.client_mac, 6);
        }
 
        if (!client_config.vendorclass)
                client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0);
 
-       /* setup the signal pipe */
+       /* Set up the signal pipe */
        udhcp_sp_setup();
 
        state = INIT_SELECTING;
@@ -324,7 +339,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
         * "continue" statements in code below jump to the top of the loop.
         */
        for (;;) {
-               unsigned timestamp_before_wait;
+               /* silence "uninitialized!" warning */
+               unsigned timestamp_before_wait = timestamp_before_wait;
 
                //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
 
@@ -340,14 +356,16 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                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) {
+               if ((int)tv.tv_sec > 0) {
                        timestamp_before_wait = (unsigned)monotonic_sec();
-                       DEBUG("Waiting on select...");
+                       log1("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)
+                               if (errno == EINTR) {
+                                       already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
                                        continue;
+                               }
                                /* Else: an error occured, panic! */
                                bb_perror_msg_and_die("select");
                        }
@@ -365,9 +383,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                if (packet_num < discover_retries) {
                                        if (packet_num == 0)
                                                xid = random_xid();
-
-                                       send_discover(xid, requested_ip); /* broadcast */
-
+                                       /* broadcast */
+                                       send_discover(xid, requested_ip);
                                        timeout = discover_timeout;
                                        packet_num++;
                                        continue;
@@ -391,64 +408,62 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                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);
-
+                                       /* send broadcast select packet */
+                                       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
+                               /* Timed out, go back to init state.
+                                * "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;
-                               }
+                               change_listen_mode(LISTEN_RAW);
                                state = INIT_SELECTING;
-                               timeout = 0;
-                               packet_num = 0;
-                               continue;
+                               goto leasefail;
                        case BOUND:
-                               /* Half of the lease passed, time to enter renewing state */
-                               change_listen_mode(LISTEN_KERNEL);
-                               DEBUG("Entering renew state");
+                               /* 1/2 lease passed, enter renewing state */
                                state = RENEWING;
+                               change_listen_mode(LISTEN_KERNEL);
+                               log1("Entering renew state");
                                /* fall right through */
+                       case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
+                       case_RENEW_REQUESTED:
                        case RENEWING:
                                if (timeout > 60) {
-                                       /* send a request packet */
-                                       send_renew(xid, server_addr, requested_ip); /* unicast */
+                                       /* send an unicast renew request */
+                       /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
+                        * a new UDP socket for sending inside send_renew.
+                        * I hazard to guess existing listening socket
+                        * is somehow conflicting with it, but why is it
+                        * not deterministic then?! Strange.
+                        * Anyway, it does recover by eventually failing through
+                        * into INIT_SELECTING state.
+                        */
+                                       send_renew(xid, server_addr, requested_ip);
                                        timeout >>= 1;
                                        continue;
                                }
                                /* Timed out, enter rebinding state */
-                               DEBUG("Entering rebinding state");
+                               log1("Entering rebinding state");
                                state = REBINDING;
                                /* fall right through */
                        case REBINDING:
+                               /* Switch to bcast receive */
+                               change_listen_mode(LISTEN_RAW);
                                /* 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 */
+                                       /* send a broadcast renew request */
+                                       send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
                                        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;
@@ -458,20 +473,48 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                        /* yah, I know, *you* say it would never happen */
                        timeout = INT_MAX;
                        continue; /* back to main loop */
+               } /* if select timed out */
+
+               /* select() didn't timeout, something happened */
+
+               /* Is it a signal? */
+               /* note: udhcp_sp_read checks FD_ISSET before reading */
+               switch (udhcp_sp_read(&rfds)) {
+               case SIGUSR1:
+                       perform_renew();
+                       if (state == RENEW_REQUESTED)
+                               goto case_RENEW_REQUESTED;
+                       /* Start things over */
+                       packet_num = 0;
+                       /* Kill any timeouts, user wants this to hurry along */
+                       timeout = 0;
+                       continue;
+               case SIGUSR2:
+                       perform_release(requested_ip, server_addr);
+                       timeout = INT_MAX;
+                       continue;
+               case SIGTERM:
+                       bb_info_msg("Received SIGTERM");
+                       if (opt & OPT_R) /* release on quit */
+                               perform_release(requested_ip, server_addr);
+                       goto ret0;
                }
 
-               /* select() didn't timeout, something did happen. */
                /* Is it a packet? */
-               if (listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) {
+               if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
+                       continue; /* no */
+
+               {
                        int len;
-                       /* A packet is ready, read it */
 
+                       /* 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));
+                       if (len == -1) {
+                               /* Error is severe, reopen socket */
+                               bb_info_msg("Read error: %s, reopening socket", strerror(errno));
                                sleep(discover_timeout); /* 3 seconds by default */
                                change_listen_mode(listen_mode); /* just close and reopen */
                        }
@@ -481,67 +524,71 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                        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;
-                       }
+               if (packet.xid != xid) {
+                       log1("xid %x (our is %x), ignoring packet",
+                               (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;
-                       }
+               /* Ignore packets that aren't for us */
+               if (packet.hlen != 6
+                || memcmp(packet.chaddr, client_config.client_mac, 6)
+               ) {
+//FIXME: need to also check that last 10 bytes are zero
+                       log1("chaddr does not match, ignoring packet"); // log2?
+                       continue;
+               }
 
-                       message = get_option(&packet, DHCP_MESSAGE_TYPE);
-                       if (message == NULL) {
-                               bb_error_msg("cannot get message type from packet - ignoring");
-                               continue;
-                       }
+               message = get_option(&packet, DHCP_MESSAGE_TYPE);
+               if (message == NULL) {
+                       bb_error_msg("no message type option, ignoring packet");
+                       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 */
-                                       }
+               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" */
+                               move_from_unaligned32(server_addr, temp);
+                               xid = packet.xid;
+                               requested_ip = packet.yiaddr;
+
+                               /* enter requesting state */
+                               state = REQUESTING;
+                               timeout = 0;
+                               packet_num = 0;
+                               already_waited_sec = 0;
+                       }
+                       continue;
+               case REQUESTING:
+               case RENEWING:
+               case RENEW_REQUESTED:
+               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" */
-                                       move_from_unaligned32(server_addr, temp);
-                                       xid = packet.xid;
-                                       requested_ip = packet.yiaddr;
-
-                                       /* enter requesting state */
-                                       state = REQUESTING;
-                                       timeout = 0;
-                                       packet_num = 0;
-                                       already_waited_sec = 0;
+                                       move_from_unaligned32(lease_seconds, 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;
                                }
-                               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" */
-                                               move_from_unaligned32(lease_seconds, 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) {
+                               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
@@ -551,99 +598,77 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
  * 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);
+                                       if (!arpping(packet.yiaddr,
+                                                       NULL,
+                                                       (uint32_t) 0,
+                                                       client_config.client_mac,
+                                                       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
-                                       already_waited_sec = 0;
-                                       continue; /* back to main loop */
+                               /* 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);
                                }
-                               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;
+                               requested_ip = packet.yiaddr;
+                               udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
+
+                               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;
                                }
-                               continue;
-                       /* case BOUND, RELEASED: - ignore all packets */
+                               /* future renew failures should not exit (JM) */
+                               opt &= ~OPT_n;
+#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 */
                        }
-                       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 */
+                       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;
-                               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;
+                               packet_num = 0;
+                               already_waited_sec = 0;
                        }
+                       continue;
+               /* case BOUND: - ignore all packets */
+               /* case RELEASED: - ignore all packets */
                }
+               /* back to main loop */
        } /* for (;;) - main loop ends */
 
  ret0: