networking/udhcp/dhcpc.c

   1 /* vi: set sw=4 ts=4: */
   2 /* dhcpc.c
   3  *
   4  * udhcp DHCP client
   5  *
   6  * Russ Dill <Russ.Dill@asu.edu> July 2001
   7  *
   8  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
   9  */
  10
  11 #include <syslog.h>
  12
  13 /* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
  14 #define WANT_PIDFILE 1
  15 #include "common.h"
  16 #include "dhcpd.h"
  17 #include "dhcpc.h"
  18 #include "options.h"
  19
  20
  21 static int sockfd = -1;
  22
  23 #define LISTEN_NONE   0
  24 #define LISTEN_KERNEL 1
  25 #define LISTEN_RAW    2
  26 static smallint listen_mode;
  27
  28 #define INIT_SELECTING  0
  29 #define REQUESTING      1
  30 #define BOUND           2
  31 #define RENEWING        3
  32 #define REBINDING       4
  33 #define INIT_REBOOT     5
  34 #define RENEW_REQUESTED 6
  35 #define RELEASED        7
  36 static smallint state;
  37
  38 /* struct client_config_t client_config is in bb_common_bufsiz1 */
  39
  40
  41 /* just a little helper */
  42 static void change_listen_mode(int new_mode)
  43 {
  44         log1("Entering listen mode: %s",
  45                 new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
  46
  47         listen_mode = new_mode;
  48         if (sockfd >= 0) {
  49                 close(sockfd);
  50                 sockfd = -1;
  51         }
  52         if (new_mode == LISTEN_KERNEL)
  53                 sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
  54         else if (new_mode != LISTEN_NONE)
  55                 sockfd = udhcp_raw_socket(client_config.ifindex);
  56         /* else LISTEN_NONE: sockfd stay closed */
  57 }
  58
  59
  60 /* perform a renew */
  61 static void perform_renew(void)
  62 {
  63         bb_info_msg("Performing a DHCP renew");
  64         switch (state) {
  65         case BOUND:
  66                 change_listen_mode(LISTEN_KERNEL);
  67         case RENEWING:
  68         case REBINDING:
  69                 state = RENEW_REQUESTED;
  70                 break;
  71         case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
  72                 udhcp_run_script(NULL, "deconfig");
  73         case REQUESTING:
  74         case RELEASED:
  75                 change_listen_mode(LISTEN_RAW);
  76                 state = INIT_SELECTING;
  77                 break;
  78         case INIT_SELECTING:
  79                 break;
  80         }
  81 }
  82
  83
  84 /* perform a release */
  85 static void perform_release(uint32_t requested_ip, uint32_t server_addr)
  86 {
  87         char buffer[sizeof("255.255.255.255")];
  88         struct in_addr temp_addr;
  89
  90         /* send release packet */
  91         if (state == BOUND || state == RENEWING || state == REBINDING) {
  92                 temp_addr.s_addr = server_addr;
  93                 strcpy(buffer, inet_ntoa(temp_addr));
  94                 temp_addr.s_addr = requested_ip;
  95                 bb_info_msg("Unicasting a release of %s to %s",
  96                                 inet_ntoa(temp_addr), buffer);
  97                 send_release(server_addr, requested_ip); /* unicast */
  98                 udhcp_run_script(NULL, "deconfig");
  99         }
 100         bb_info_msg("Entering released state");
 101
 102         change_listen_mode(LISTEN_NONE);
 103         state = RELEASED;
 104 }
 105
 106
 107 #if BB_MMU
 108 static void client_background(void)
 109 {
 110         bb_daemonize(0);
 111         logmode &= ~LOGMODE_STDIO;
 112         /* rewrite pidfile, as our pid is different now */
 113         write_pidfile(client_config.pidfile);
 114 }
 115 #endif
 116
 117
 118 static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
 119 {
 120         uint8_t *storage;
 121         int len = strlen(str);
 122         if (len > 255) len = 255;
 123         storage = xzalloc(len + extra + OPT_DATA);
 124         storage[OPT_CODE] = code;
 125         storage[OPT_LEN] = len + extra;
 126         memcpy(storage + extra + OPT_DATA, str, len);
 127         return storage;
 128 }
 129
 130
 131 int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 132 int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 133 {
 134         uint8_t *temp, *message;
 135         char *str_c, *str_V, *str_h, *str_F, *str_r;
 136         IF_FEATURE_UDHCP_PORT(char *str_P;)
 137         llist_t *list_O = NULL;
 138         int tryagain_timeout = 20;
 139         int discover_timeout = 3;
 140         int discover_retries = 3;
 141         uint32_t server_addr = server_addr; /* for compiler */
 142         uint32_t requested_ip = 0;
 143         uint32_t xid = 0;
 144         uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */
 145         int packet_num;
 146         int timeout; /* must be signed */
 147         unsigned already_waited_sec;
 148         unsigned opt;
 149         int max_fd;
 150         int retval;
 151         struct timeval tv;
 152         struct dhcp_packet packet;
 153         fd_set rfds;
 154
 155 #if ENABLE_GETOPT_LONG
 156         static const char udhcpc_longopts[] ALIGN1 =
 157                 "clientid\0"       Required_argument "c"
 158                 "clientid-none\0"  No_argument       "C"
 159                 "vendorclass\0"    Required_argument "V"
 160                 "hostname\0"       Required_argument "H"
 161                 "fqdn\0"           Required_argument "F"
 162                 "interface\0"      Required_argument "i"
 163                 "now\0"            No_argument       "n"
 164                 "pidfile\0"        Required_argument "p"
 165                 "quit\0"           No_argument       "q"
 166                 "release\0"        No_argument       "R"
 167                 "request\0"        Required_argument "r"
 168                 "script\0"         Required_argument "s"
 169                 "timeout\0"        Required_argument "T"
 170                 "version\0"        No_argument       "v"
 171                 "retries\0"        Required_argument "t"
 172                 "tryagain\0"       Required_argument "A"
 173                 "syslog\0"         No_argument       "S"
 174                 "request-option\0" Required_argument "O"
 175                 "no-default-options\0" No_argument   "o"
 176                 "foreground\0"     No_argument       "f"
 177                 "background\0"     No_argument       "b"
 178                 IF_FEATURE_UDHCPC_ARPING("arping\0"     No_argument       "a")
 179                 IF_FEATURE_UDHCP_PORT("client-port\0"   Required_argument "P")
 180                 ;
 181 #endif
 182         enum {
 183                 OPT_c = 1 << 0,
 184                 OPT_C = 1 << 1,
 185                 OPT_V = 1 << 2,
 186                 OPT_H = 1 << 3,
 187                 OPT_h = 1 << 4,
 188                 OPT_F = 1 << 5,
 189                 OPT_i = 1 << 6,
 190                 OPT_n = 1 << 7,
 191                 OPT_p = 1 << 8,
 192                 OPT_q = 1 << 9,
 193                 OPT_R = 1 << 10,
 194                 OPT_r = 1 << 11,
 195                 OPT_s = 1 << 12,
 196                 OPT_T = 1 << 13,
 197                 OPT_t = 1 << 14,
 198                 OPT_S = 1 << 15,
 199                 OPT_A = 1 << 16,
 200                 OPT_O = 1 << 17,
 201                 OPT_o = 1 << 18,
 202                 OPT_f = 1 << 19,
 203 /* The rest has variable bit positions, need to be clever */
 204                 OPTBIT_f = 19,
 205                 USE_FOR_MMU(             OPTBIT_b,)
 206                 IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
 207                 IF_FEATURE_UDHCP_PORT(   OPTBIT_P,)
 208                 USE_FOR_MMU(             OPT_b = 1 << OPTBIT_b,)
 209                 IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
 210                 IF_FEATURE_UDHCP_PORT(   OPT_P = 1 << OPTBIT_P,)
 211         };
 212
 213         /* Default options. */
 214         IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
 215         IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
 216         client_config.interface = "eth0";
 217         client_config.script = DEFAULT_SCRIPT;
 218
 219         /* Parse command line */
 220         /* Cc: mutually exclusive; O: list; -T,-t,-A take numeric param */
 221         opt_complementary = "c--C:C--c:O::T+:t+:A+"
 222 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
 223                 ":vv"
 224 #endif
 225                 ;
 226         IF_GETOPT_LONG(applet_long_options = udhcpc_longopts;)
 227         opt = getopt32(argv, "c:CV:H:h:F:i:np:qRr:s:T:t:SA:O:of"
 228                 USE_FOR_MMU("b")
 229                 IF_FEATURE_UDHCPC_ARPING("a")
 230                 IF_FEATURE_UDHCP_PORT("P:")
 231                 "v"
 232                 , &str_c, &str_V, &str_h, &str_h, &str_F
 233                 , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
 234                 , &client_config.script /* s */
 235                 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
 236                 , &list_O
 237                 IF_FEATURE_UDHCP_PORT(, &str_P)
 238 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
 239                 , &dhcp_verbose
 240 #endif
 241                 );
 242         if (opt & OPT_c)
 243                 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
 244         if (opt & OPT_V)
 245                 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
 246         if (opt & (OPT_h|OPT_H))
 247                 client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
 248         if (opt & OPT_F) {
 249                 client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
 250                 /* Flags: 0000NEOS
 251                 S: 1 => Client requests Server to update A RR in DNS as well as PTR
 252                 O: 1 => Server indicates to client that DNS has been updated regardless
 253                 E: 1 => Name data is DNS format, i.e. <4>host<6>domain<3>com<0> not "host.domain.com"
 254                 N: 1 => Client requests Server to not update DNS
 255                 */
 256                 client_config.fqdn[OPT_DATA + 0] = 0x1;
 257                 /* client_config.fqdn[OPT_DATA + 1] = 0; - redundant */
 258                 /* client_config.fqdn[OPT_DATA + 2] = 0; - redundant */
 259         }
 260         if (opt & OPT_r)
 261                 requested_ip = inet_addr(str_r);
 262 #if ENABLE_FEATURE_UDHCP_PORT
 263         if (opt & OPT_P) {
 264                 CLIENT_PORT = xatou16(str_P);
 265                 SERVER_PORT = CLIENT_PORT - 1;
 266         }
 267 #endif
 268         if (opt & OPT_o)
 269                 client_config.no_default_options = 1;
 270         while (list_O) {
 271                 char *optstr = llist_pop(&list_O);
 272                 int n = index_in_strings(dhcp_option_strings, optstr);
 273                 if (n < 0)
 274                         bb_error_msg_and_die("unknown option '%s'", optstr);
 275                 n = dhcp_options[n].code;
 276                 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
 277         }
 278
 279         if (udhcp_read_interface(client_config.interface,
 280                         &client_config.ifindex,
 281                         NULL,
 282                         client_config.client_mac)
 283         ) {
 284                 return 1;
 285         }
 286
 287 #if !BB_MMU
 288         /* on NOMMU reexec (i.e., background) early */
 289         if (!(opt & OPT_f)) {
 290                 bb_daemonize_or_rexec(0 /* flags */, argv);
 291                 logmode = LOGMODE_NONE;
 292         }
 293 #endif
 294         if (opt & OPT_S) {
 295                 openlog(applet_name, LOG_PID, LOG_DAEMON);
 296                 logmode |= LOGMODE_SYSLOG;
 297         }
 298
 299         /* Make sure fd 0,1,2 are open */
 300         bb_sanitize_stdio();
 301         /* Equivalent of doing a fflush after every \n */
 302         setlinebuf(stdout);
 303
 304         /* Create pidfile */
 305         write_pidfile(client_config.pidfile);
 306
 307         /* Goes to stdout (unless NOMMU) and possibly syslog */
 308         bb_info_msg("%s (v"BB_VER") started", applet_name);
 309
 310         /* if not set, and not suppressed, setup the default client ID */
 311         if (!client_config.clientid && !(opt & OPT_C)) {
 312                 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
 313                 client_config.clientid[OPT_DATA] = 1;
 314                 memcpy(client_config.clientid + OPT_DATA+1, client_config.client_mac, 6);
 315         }
 316
 317         if (!client_config.vendorclass)
 318                 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0);
 319
 320         /* setup the signal pipe */
 321         udhcp_sp_setup();
 322
 323         state = INIT_SELECTING;
 324         udhcp_run_script(NULL, "deconfig");
 325         change_listen_mode(LISTEN_RAW);
 326         packet_num = 0;
 327         timeout = 0;
 328         already_waited_sec = 0;
 329
 330         /* Main event loop. select() waits on signal pipe and possibly
 331          * on sockfd.
 332          * "continue" statements in code below jump to the top of the loop.
 333          */
 334         for (;;) {
 335                 /* silence "uninitialized!" warning */
 336                 unsigned timestamp_before_wait = timestamp_before_wait;
 337
 338                 //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
 339
 340                 /* Was opening raw or udp socket here
 341                  * if (listen_mode != LISTEN_NONE && sockfd < 0),
 342                  * but on fast network renew responses return faster
 343                  * than we open sockets. Thus this code is moved
 344                  * to change_listen_mode(). Thus we open listen socket
 345                  * BEFORE we send renew request (see "case BOUND:"). */
 346
 347                 max_fd = udhcp_sp_fd_set(&rfds, sockfd);
 348
 349                 tv.tv_sec = timeout - already_waited_sec;
 350                 tv.tv_usec = 0;
 351                 retval = 0; /* If we already timed out, fall through, else... */
 352                 if (tv.tv_sec > 0) {
 353                         timestamp_before_wait = (unsigned)monotonic_sec();
 354                         log1("Waiting on select...");
 355                         retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
 356                         if (retval < 0) {
 357                                 /* EINTR? A signal was caught, don't panic */
 358                                 if (errno == EINTR)
 359                                         continue;
 360                                 /* Else: an error occured, panic! */
 361                                 bb_perror_msg_and_die("select");
 362                         }
 363                 }
 364
 365                 /* If timeout dropped to zero, time to become active:
 366                  * resend discover/renew/whatever
 367                  */
 368                 if (retval == 0) {
 369                         /* We will restart the wait in any case */
 370                         already_waited_sec = 0;
 371
 372                         switch (state) {
 373                         case INIT_SELECTING:
 374                                 if (packet_num < discover_retries) {
 375                                         if (packet_num == 0)
 376                                                 xid = random_xid();
 377
 378                                         send_discover(xid, requested_ip); /* broadcast */
 379
 380                                         timeout = discover_timeout;
 381                                         packet_num++;
 382                                         continue;
 383                                 }
 384  leasefail:
 385                                 udhcp_run_script(NULL, "leasefail");
 386 #if BB_MMU /* -b is not supported on NOMMU */
 387                                 if (opt & OPT_b) { /* background if no lease */
 388                                         bb_info_msg("No lease, forking to background");
 389                                         client_background();
 390                                         /* do not background again! */
 391                                         opt = ((opt & ~OPT_b) | OPT_f);
 392                                 } else
 393 #endif
 394                                 if (opt & OPT_n) { /* abort if no lease */
 395                                         bb_info_msg("No lease, failing");
 396                                         retval = 1;
 397                                         goto ret;
 398                                 }
 399                                 /* wait before trying again */
 400                                 timeout = tryagain_timeout;
 401                                 packet_num = 0;
 402                                 continue;
 403                         case RENEW_REQUESTED:
 404                         case REQUESTING:
 405                                 if (packet_num < discover_retries) {
 406                                         /* send request packet */
 407                                         if (state == RENEW_REQUESTED) /* unicast */
 408                                                 send_renew(xid, server_addr, requested_ip);
 409                                         else /* broadcast */
 410                                                 send_select(xid, server_addr, requested_ip);
 411
 412                                         timeout = discover_timeout;
 413                                         packet_num++;
 414                                         continue;
 415                                 }
 416                                 /* timed out, go back to init state */
 417                                 if (state == RENEW_REQUESTED)
 418                                         udhcp_run_script(NULL, "deconfig");
 419                                 change_listen_mode(LISTEN_RAW);
 420                                 /* "discover...select...discover..." loops
 421                                  * were seen in the wild. Treat them similarly
 422                                  * to "no response to discover" case */
 423                                 if (state == REQUESTING) {
 424                                         state = INIT_SELECTING;
 425                                         goto leasefail;
 426                                 }
 427                                 state = INIT_SELECTING;
 428                                 timeout = 0;
 429                                 packet_num = 0;
 430                                 continue;
 431                         case BOUND:
 432                                 /* Half of the lease passed, time to enter renewing state */
 433                                 change_listen_mode(LISTEN_KERNEL);
 434                                 log1("Entering renew state");
 435                                 state = RENEWING;
 436                                 /* fall right through */
 437                         case RENEWING:
 438                                 if (timeout > 60) {
 439                                         /* send a request packet */
 440                                         send_renew(xid, server_addr, requested_ip); /* unicast */
 441                                         timeout >>= 1;
 442                                         continue;
 443                                 }
 444                                 /* Timed out, enter rebinding state */
 445                                 log1("Entering rebinding state");
 446                                 state = REBINDING;
 447                                 /* fall right through */
 448                         case REBINDING:
 449                                 /* Lease is *really* about to run out,
 450                                  * try to find DHCP server using broadcast */
 451                                 if (timeout > 0) {
 452                                         /* send a request packet */
 453                                         send_renew(xid, 0 /*INADDR_ANY*/, requested_ip); /* broadcast */
 454                                         timeout >>= 1;
 455                                         continue;
 456                                 }
 457                                 /* Timed out, enter init state */
 458                                 bb_info_msg("Lease lost, entering init state");
 459                                 udhcp_run_script(NULL, "deconfig");
 460                                 change_listen_mode(LISTEN_RAW);
 461                                 state = INIT_SELECTING;
 462                                 /*timeout = 0; - already is */
 463                                 packet_num = 0;
 464                                 continue;
 465                         /* case RELEASED: */
 466                         }
 467                         /* yah, I know, *you* say it would never happen */
 468                         timeout = INT_MAX;
 469                         continue; /* back to main loop */
 470                 }
 471
 472                 /* select() didn't timeout, something did happen. */
 473                 /* Is it a packet? */
 474                 if (listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) {
 475                         int len;
 476                         /* A packet is ready, read it */
 477
 478                         if (listen_mode == LISTEN_KERNEL)
 479                                 len = udhcp_recv_kernel_packet(&packet, sockfd);
 480                         else
 481                                 len = udhcp_recv_raw_packet(&packet, sockfd);
 482                         if (len == -1) { /* error is severe, reopen socket */
 483                                 bb_info_msg("Read error: %s, reopening socket", strerror(errno));
 484                                 sleep(discover_timeout); /* 3 seconds by default */
 485                                 change_listen_mode(listen_mode); /* just close and reopen */
 486                         }
 487                         /* If this packet will turn out to be unrelated/bogus,
 488                          * we will go back and wait for next one.
 489                          * Be sure timeout is properly decreased. */
 490                         already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
 491                         if (len < 0)
 492                                 continue;
 493
 494                         if (packet.xid != xid) {
 495                                 log1("xid %x (our is %x), ignoring packet",
 496                                         (unsigned)packet.xid, (unsigned)xid);
 497                                 continue;
 498                         }
 499
 500                         /* Ignore packets that aren't for us */
 501                         if (packet.hlen != 6
 502                          || memcmp(packet.chaddr, client_config.client_mac, 6)
 503                         ) {
 504 //FIXME: need to also check that last 10 bytes are zero
 505                                 log1("chaddr does not match, ignoring packet"); // log2?
 506                                 continue;
 507                         }
 508
 509                         message = get_option(&packet, DHCP_MESSAGE_TYPE);
 510                         if (message == NULL) {
 511                                 bb_error_msg("no message type option, ignoring packet");
 512                                 continue;
 513                         }
 514
 515                         switch (state) {
 516                         case INIT_SELECTING:
 517                                 /* Must be a DHCPOFFER to one of our xid's */
 518                                 if (*message == DHCPOFFER) {
 519                         /* TODO: why we don't just fetch server's IP from IP header? */
 520                                         temp = get_option(&packet, DHCP_SERVER_ID);
 521                                         if (!temp) {
 522                                                 bb_error_msg("no server ID in message");
 523                                                 continue;
 524                                                 /* still selecting - this server looks bad */
 525                                         }
 526                                         /* it IS unaligned sometimes, don't "optimize" */
 527                                         move_from_unaligned32(server_addr, temp);
 528                                         xid = packet.xid;
 529                                         requested_ip = packet.yiaddr;
 530
 531                                         /* enter requesting state */
 532                                         state = REQUESTING;
 533                                         timeout = 0;
 534                                         packet_num = 0;
 535                                         already_waited_sec = 0;
 536                                 }
 537                                 continue;
 538                         case RENEW_REQUESTED:
 539                         case REQUESTING:
 540                         case RENEWING:
 541                         case REBINDING:
 542                                 if (*message == DHCPACK) {
 543                                         temp = get_option(&packet, DHCP_LEASE_TIME);
 544                                         if (!temp) {
 545                                                 bb_error_msg("no lease time with ACK, using 1 hour lease");
 546                                                 lease_seconds = 60 * 60;
 547                                         } else {
 548                                                 /* it IS unaligned sometimes, don't "optimize" */
 549                                                 move_from_unaligned32(lease_seconds, temp);
 550                                                 lease_seconds = ntohl(lease_seconds);
 551                                                 lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
 552                                                 if (lease_seconds < 10) /* and not too small */
 553                                                         lease_seconds = 10;
 554                                         }
 555 #if ENABLE_FEATURE_UDHCPC_ARPING
 556                                         if (opt & OPT_a) {
 557 /* RFC 2131 3.1 paragraph 5:
 558  * "The client receives the DHCPACK message with configuration
 559  * parameters. The client SHOULD perform a final check on the
 560  * parameters (e.g., ARP for allocated network address), and notes
 561  * the duration of the lease specified in the DHCPACK message. At this
 562  * point, the client is configured. If the client detects that the
 563  * address is already in use (e.g., through the use of ARP),
 564  * the client MUST send a DHCPDECLINE message to the server and restarts
 565  * the configuration process..." */
 566                                                 if (!arpping(packet.yiaddr,
 567                                                                 NULL,
 568                                                                 (uint32_t) 0,
 569                                                                 client_config.client_mac,
 570                                                                 client_config.interface)
 571                                                 ) {
 572                                                         bb_info_msg("Offered address is in use "
 573                                                                 "(got ARP reply), declining");
 574                                                         send_decline(xid, server_addr, packet.yiaddr);
 575
 576                                                         if (state != REQUESTING)
 577                                                                 udhcp_run_script(NULL, "deconfig");
 578                                                         change_listen_mode(LISTEN_RAW);
 579                                                         state = INIT_SELECTING;
 580                                                         requested_ip = 0;
 581                                                         timeout = tryagain_timeout;
 582                                                         packet_num = 0;
 583                                                         already_waited_sec = 0;
 584                                                         continue; /* back to main loop */
 585                                                 }
 586                                         }
 587 #endif
 588                                         /* enter bound state */
 589                                         timeout = lease_seconds / 2;
 590                                         {
 591                                                 struct in_addr temp_addr;
 592                                                 temp_addr.s_addr = packet.yiaddr;
 593                                                 bb_info_msg("Lease of %s obtained, lease time %u",
 594                                                         inet_ntoa(temp_addr), (unsigned)lease_seconds);
 595                                         }
 596                                         requested_ip = packet.yiaddr;
 597                                         udhcp_run_script(&packet,
 598                                                         ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
 599
 600                                         state = BOUND;
 601                                         change_listen_mode(LISTEN_NONE);
 602                                         if (opt & OPT_q) { /* quit after lease */
 603                                                 if (opt & OPT_R) /* release on quit */
 604                                                         perform_release(requested_ip, server_addr);
 605                                                 goto ret0;
 606                                         }
 607 #if BB_MMU /* NOMMU case backgrounded earlier */
 608                                         if (!(opt & OPT_f)) {
 609                                                 client_background();
 610                                                 /* do not background again! */
 611                                                 opt = ((opt & ~OPT_b) | OPT_f);
 612                                         }
 613 #endif
 614                                         already_waited_sec = 0;
 615                                         continue; /* back to main loop */
 616                                 }
 617                                 if (*message == DHCPNAK) {
 618                                         /* return to init state */
 619                                         bb_info_msg("Received DHCP NAK");
 620                                         udhcp_run_script(&packet, "nak");
 621                                         if (state != REQUESTING)
 622                                                 udhcp_run_script(NULL, "deconfig");
 623                                         change_listen_mode(LISTEN_RAW);
 624                                         sleep(3); /* avoid excessive network traffic */
 625                                         state = INIT_SELECTING;
 626                                         requested_ip = 0;
 627                                         timeout = 0;
 628                                         packet_num = 0;
 629                                         already_waited_sec = 0;
 630                                 }
 631                                 continue;
 632                         /* case BOUND, RELEASED: - ignore all packets */
 633                         }
 634                         continue; /* back to main loop */
 635                 }
 636
 637                 /* select() didn't timeout, something did happen.
 638                  * But it wasn't a packet. It's a signal pipe then. */
 639                 {
 640                         int signo = udhcp_sp_read(&rfds);
 641                         switch (signo) {
 642                         case SIGUSR1:
 643                                 perform_renew();
 644                                 /* start things over */
 645                                 packet_num = 0;
 646                                 /* Kill any timeouts because the user wants this to hurry along */
 647                                 timeout = 0;
 648                                 break;
 649                         case SIGUSR2:
 650                                 perform_release(requested_ip, server_addr);
 651                                 timeout = INT_MAX;
 652                                 break;
 653                         case SIGTERM:
 654                                 bb_info_msg("Received SIGTERM");
 655                                 if (opt & OPT_R) /* release on quit */
 656                                         perform_release(requested_ip, server_addr);
 657                                 goto ret0;
 658                         }
 659                 }
 660         } /* for (;;) - main loop ends */
 661
 662  ret0:
 663         retval = 0;
 664  ret:
 665         /*if (client_config.pidfile) - remove_pidfile has its own check */
 666                 remove_pidfile(client_config.pidfile);
 667         return retval;
 668 }