networking/udhcp/dhcpc.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * udhcp client
   4  *
   5  * Russ Dill <Russ.Dill@asu.edu> July 2001
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21 #include <syslog.h>
  22 /* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
  23 #define WANT_PIDFILE 1
  24 #include "common.h"
  25 #include "dhcpd.h"
  26 #include "dhcpc.h"
  27
  28 #include <netinet/if_ether.h>
  29 #include <netpacket/packet.h>
  30 #include <linux/filter.h>
  31
  32 /* "struct client_config_t client_config" is in bb_common_bufsiz1 */
  33
  34
  35 #if ENABLE_LONG_OPTS
  36 static const char udhcpc_longopts[] ALIGN1 =
  37         "clientid-none\0"  No_argument       "C"
  38         "vendorclass\0"    Required_argument "V"
  39         "hostname\0"       Required_argument "H"
  40         "fqdn\0"           Required_argument "F"
  41         "interface\0"      Required_argument "i"
  42         "now\0"            No_argument       "n"
  43         "pidfile\0"        Required_argument "p"
  44         "quit\0"           No_argument       "q"
  45         "release\0"        No_argument       "R"
  46         "request\0"        Required_argument "r"
  47         "script\0"         Required_argument "s"
  48         "timeout\0"        Required_argument "T"
  49         "retries\0"        Required_argument "t"
  50         "tryagain\0"       Required_argument "A"
  51         "syslog\0"         No_argument       "S"
  52         "request-option\0" Required_argument "O"
  53         "no-default-options\0" No_argument   "o"
  54         "foreground\0"     No_argument       "f"
  55         "background\0"     No_argument       "b"
  56         "broadcast\0"      No_argument       "B"
  57         IF_FEATURE_UDHCPC_ARPING("arping\0"     No_argument       "a")
  58         IF_FEATURE_UDHCP_PORT("client-port\0"   Required_argument "P")
  59         ;
  60 #endif
  61 /* Must match getopt32 option string order */
  62 enum {
  63         OPT_C = 1 << 0,
  64         OPT_V = 1 << 1,
  65         OPT_H = 1 << 2,
  66         OPT_h = 1 << 3,
  67         OPT_F = 1 << 4,
  68         OPT_i = 1 << 5,
  69         OPT_n = 1 << 6,
  70         OPT_p = 1 << 7,
  71         OPT_q = 1 << 8,
  72         OPT_R = 1 << 9,
  73         OPT_r = 1 << 10,
  74         OPT_s = 1 << 11,
  75         OPT_T = 1 << 12,
  76         OPT_t = 1 << 13,
  77         OPT_S = 1 << 14,
  78         OPT_A = 1 << 15,
  79         OPT_O = 1 << 16,
  80         OPT_o = 1 << 17,
  81         OPT_x = 1 << 18,
  82         OPT_f = 1 << 19,
  83         OPT_B = 1 << 20,
  84 /* The rest has variable bit positions, need to be clever */
  85         OPTBIT_B = 20,
  86         USE_FOR_MMU(             OPTBIT_b,)
  87         IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
  88         IF_FEATURE_UDHCP_PORT(   OPTBIT_P,)
  89         USE_FOR_MMU(             OPT_b = 1 << OPTBIT_b,)
  90         IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
  91         IF_FEATURE_UDHCP_PORT(   OPT_P = 1 << OPTBIT_P,)
  92 };
  93
  94
  95 /*** Script execution code ***/
  96
  97 /* get a rough idea of how long an option will be (rounding up...) */
  98 static const uint8_t len_of_option_as_string[] = {
  99         [OPTION_IP              ] = sizeof("255.255.255.255 "),
 100         [OPTION_IP_PAIR         ] = sizeof("255.255.255.255 ") * 2,
 101         [OPTION_STATIC_ROUTES   ] = sizeof("255.255.255.255/32 255.255.255.255 "),
 102         [OPTION_6RD             ] = sizeof("32 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 "),
 103         [OPTION_STRING          ] = 1,
 104 #if ENABLE_FEATURE_UDHCP_RFC3397
 105         [OPTION_DNS_STRING      ] = 1, /* unused */
 106         /* Hmmm, this severely overestimates size if SIP_SERVERS option
 107          * is in domain name form: N-byte option in binary form
 108          * mallocs ~16*N bytes. But it is freed almost at once.
 109          */
 110         [OPTION_SIP_SERVERS     ] = sizeof("255.255.255.255 "),
 111 #endif
 112 //      [OPTION_BOOLEAN         ] = sizeof("yes "),
 113         [OPTION_U8              ] = sizeof("255 "),
 114         [OPTION_U16             ] = sizeof("65535 "),
 115 //      [OPTION_S16             ] = sizeof("-32768 "),
 116         [OPTION_U32             ] = sizeof("4294967295 "),
 117         [OPTION_S32             ] = sizeof("-2147483684 "),
 118 };
 119
 120 /* note: ip is a pointer to an IP in network order, possibly misaliged */
 121 static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
 122 {
 123         return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
 124 }
 125
 126 /* really simple implementation, just count the bits */
 127 static int mton(uint32_t mask)
 128 {
 129         int i = 0;
 130         mask = ntohl(mask); /* 111110000-like bit pattern */
 131         while (mask) {
 132                 i++;
 133                 mask <<= 1;
 134         }
 135         return i;
 136 }
 137
 138 /* Create "opt_name=opt_value" string */
 139 static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name)
 140 {
 141         unsigned upper_length;
 142         int len, type, optlen;
 143         char *dest, *ret;
 144
 145         /* option points to OPT_DATA, need to go back to get OPT_LEN */
 146         len = option[-OPT_DATA + OPT_LEN];
 147
 148         type = optflag->flags & OPTION_TYPE_MASK;
 149         optlen = dhcp_option_lengths[type];
 150         upper_length = len_of_option_as_string[type]
 151                 * ((unsigned)(len + optlen - 1) / (unsigned)optlen);
 152
 153         dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
 154         dest += sprintf(ret, "%s=", opt_name);
 155
 156         while (len >= optlen) {
 157                 switch (type) {
 158                 case OPTION_IP:
 159                 case OPTION_IP_PAIR:
 160                         dest += sprint_nip(dest, "", option);
 161                         if (type == OPTION_IP)
 162                                 break;
 163                         dest += sprint_nip(dest, "/", option + 4);
 164                         break;
 165 //              case OPTION_BOOLEAN:
 166 //                      dest += sprintf(dest, *option ? "yes" : "no");
 167 //                      break;
 168                 case OPTION_U8:
 169                         dest += sprintf(dest, "%u", *option);
 170                         break;
 171 //              case OPTION_S16:
 172                 case OPTION_U16: {
 173                         uint16_t val_u16;
 174                         move_from_unaligned16(val_u16, option);
 175                         dest += sprintf(dest, "%u", ntohs(val_u16));
 176                         break;
 177                 }
 178                 case OPTION_S32:
 179                 case OPTION_U32: {
 180                         uint32_t val_u32;
 181                         move_from_unaligned32(val_u32, option);
 182                         dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
 183                         break;
 184                 }
 185                 /* Note: options which use 'return' instead of 'break'
 186                  * (for example, OPTION_STRING) skip the code which handles
 187                  * the case of list of options.
 188                  */
 189                 case OPTION_STRING:
 190                         memcpy(dest, option, len);
 191                         dest[len] = '\0';
 192                         return ret;
 193                 case OPTION_STATIC_ROUTES: {
 194                         /* Option binary format:
 195                          * mask [one byte, 0..32]
 196                          * ip [big endian, 0..4 bytes depending on mask]
 197                          * router [big endian, 4 bytes]
 198                          * may be repeated
 199                          *
 200                          * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
 201                          */
 202                         const char *pfx = "";
 203
 204                         while (len >= 1 + 4) { /* mask + 0-byte ip + router */
 205                                 uint32_t nip;
 206                                 uint8_t *p;
 207                                 unsigned mask;
 208                                 int bytes;
 209
 210                                 mask = *option++;
 211                                 if (mask > 32)
 212                                         break;
 213                                 len--;
 214
 215                                 nip = 0;
 216                                 p = (void*) &nip;
 217                                 bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
 218                                 while (--bytes >= 0) {
 219                                         *p++ = *option++;
 220                                         len--;
 221                                 }
 222                                 if (len < 4)
 223                                         break;
 224
 225                                 /* print ip/mask */
 226                                 dest += sprint_nip(dest, pfx, (void*) &nip);
 227                                 pfx = " ";
 228                                 dest += sprintf(dest, "/%u ", mask);
 229                                 /* print router */
 230                                 dest += sprint_nip(dest, "", option);
 231                                 option += 4;
 232                                 len -= 4;
 233                         }
 234
 235                         return ret;
 236                 }
 237                 case OPTION_6RD:
 238                         /* Option binary format (see RFC 5969):
 239                          *  0                   1                   2                   3
 240                          *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 241                          * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 242                          * |  OPTION_6RD   | option-length |  IPv4MaskLen  |  6rdPrefixLen |
 243                          * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 244                          * |                           6rdPrefix                           |
 245                          * ...                        (16 octets)                        ...
 246                          * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 247                          * ...                   6rdBRIPv4Address(es)                    ...
 248                          * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 249                          * We convert it to a string
 250                          * "IPv4MaskLen 6rdPrefixLen 6rdPrefix 6rdBRIPv4Address..."
 251                          *
 252                          * Sanity check: ensure that our length is at least 22 bytes, that
 253                          * IPv4MaskLen <= 32,
 254                          * 6rdPrefixLen <= 128,
 255                          * 6rdPrefixLen + (32 - IPv4MaskLen) <= 128
 256                          * (2nd condition need no check - it follows from 1st and 3rd).
 257                          * Else, return envvar with empty value ("optname=")
 258                          */
 259                         if (len >= (1 + 1 + 16 + 4)
 260                          && option[0] <= 32
 261                          && (option[1] + 32 - option[0]) <= 128
 262                         ) {
 263                                 /* IPv4MaskLen */
 264                                 dest += sprintf(dest, "%u ", *option++);
 265                                 /* 6rdPrefixLen */
 266                                 dest += sprintf(dest, "%u ", *option++);
 267                                 /* 6rdPrefix */
 268                                 dest += sprint_nip6(dest, /* "", */ option);
 269                                 option += 16;
 270                                 len -= 1 + 1 + 16 + 4;
 271                                 /* "+ 4" above corresponds to the length of IPv4 addr
 272                                  * we consume in the loop below */
 273                                 while (1) {
 274                                         /* 6rdBRIPv4Address(es) */
 275                                         dest += sprint_nip(dest, " ", option);
 276                                         option += 4;
 277                                         len -= 4; /* do we have yet another 4+ bytes? */
 278                                         if (len < 0)
 279                                                 break; /* no */
 280                                 }
 281                         }
 282
 283                         return ret;
 284 #if ENABLE_FEATURE_UDHCP_RFC3397
 285                 case OPTION_DNS_STRING:
 286                         /* unpack option into dest; use ret for prefix (i.e., "optname=") */
 287                         dest = dname_dec(option, len, ret);
 288                         if (dest) {
 289                                 free(ret);
 290                                 return dest;
 291                         }
 292                         /* error. return "optname=" string */
 293                         return ret;
 294                 case OPTION_SIP_SERVERS:
 295                         /* Option binary format:
 296                          * type: byte
 297                          * type=0: domain names, dns-compressed
 298                          * type=1: IP addrs
 299                          */
 300                         option++;
 301                         len--;
 302                         if (option[-1] == 0) {
 303                                 dest = dname_dec(option, len, ret);
 304                                 if (dest) {
 305                                         free(ret);
 306                                         return dest;
 307                                 }
 308                         } else
 309                         if (option[-1] == 1) {
 310                                 const char *pfx = "";
 311                                 while (1) {
 312                                         len -= 4;
 313                                         if (len < 0)
 314                                                 break;
 315                                         dest += sprint_nip(dest, pfx, option);
 316                                         pfx = " ";
 317                                         option += 4;
 318                                 }
 319                         }
 320                         return ret;
 321 #endif
 322                 } /* switch */
 323
 324                 /* If we are here, try to format any remaining data
 325                  * in the option as another, similarly-formatted option
 326                  */
 327                 option += optlen;
 328                 len -= optlen;
 329 // TODO: it can be a list only if (optflag->flags & OPTION_LIST).
 330 // Should we bail out/warn if we see multi-ip option which is
 331 // not allowed to be such (for example, DHCP_BROADCAST)? -
 332                 if (len < optlen /* || !(optflag->flags & OPTION_LIST) */)
 333                         break;
 334                 *dest++ = ' ';
 335                 *dest = '\0';
 336         } /* while */
 337
 338         return ret;
 339 }
 340
 341 /* put all the parameters into the environment */
 342 static char **fill_envp(struct dhcp_packet *packet)
 343 {
 344         int envc;
 345         int i;
 346         char **envp, **curr;
 347         const char *opt_name;
 348         uint8_t *temp;
 349         uint8_t overload = 0;
 350
 351 #define BITMAP unsigned
 352 #define BBITS (sizeof(BITMAP) * 8)
 353 #define BMASK(i) (1 << (i & (sizeof(BITMAP) * 8 - 1)))
 354 #define FOUND_OPTS(i) (found_opts[(unsigned)i / BBITS])
 355         BITMAP found_opts[256 / BBITS];
 356
 357         memset(found_opts, 0, sizeof(found_opts));
 358
 359         /* We need 6 elements for:
 360          * "interface=IFACE"
 361          * "ip=N.N.N.N" from packet->yiaddr
 362          * "siaddr=IP" from packet->siaddr_nip (unless 0)
 363          * "boot_file=FILE" from packet->file (unless overloaded)
 364          * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded)
 365          * terminating NULL
 366          */
 367         envc = 6;
 368         /* +1 element for each option, +2 for subnet option: */
 369         if (packet) {
 370                 /* note: do not search for "pad" (0) and "end" (255) options */
 371                 for (i = 1; i < 255; i++) {
 372                         temp = udhcp_get_option(packet, i);
 373                         if (temp) {
 374                                 if (i == DHCP_OPTION_OVERLOAD)
 375                                         overload = *temp;
 376                                 else if (i == DHCP_SUBNET)
 377                                         envc++; /* for $mask */
 378                                 envc++;
 379                                 /*if (i != DHCP_MESSAGE_TYPE)*/
 380                                 FOUND_OPTS(i) |= BMASK(i);
 381                         }
 382                 }
 383         }
 384         curr = envp = xzalloc(sizeof(envp[0]) * envc);
 385
 386         *curr = xasprintf("interface=%s", client_config.interface);
 387         putenv(*curr++);
 388
 389         if (!packet)
 390                 return envp;
 391
 392         /* Export BOOTP fields. Fields we don't (yet?) export:
 393          * uint8_t op;      // always BOOTREPLY
 394          * uint8_t htype;   // hardware address type. 1 = 10mb ethernet
 395          * uint8_t hlen;    // hardware address length
 396          * uint8_t hops;    // used by relay agents only
 397          * uint32_t xid;
 398          * uint16_t secs;   // elapsed since client began acquisition/renewal
 399          * uint16_t flags;  // only one flag so far: bcast. Never set by server
 400          * uint32_t ciaddr; // client IP (usually == yiaddr. can it be different
 401          *                  // if during renew server wants to give us differn IP?)
 402          * uint32_t gateway_nip; // relay agent IP address
 403          * uint8_t chaddr[16]; // link-layer client hardware address (MAC)
 404          * TODO: export gateway_nip as $giaddr?
 405          */
 406         /* Most important one: yiaddr as $ip */
 407         *curr = xmalloc(sizeof("ip=255.255.255.255"));
 408         sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
 409         putenv(*curr++);
 410         if (packet->siaddr_nip) {
 411                 /* IP address of next server to use in bootstrap */
 412                 *curr = xmalloc(sizeof("siaddr=255.255.255.255"));
 413                 sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
 414                 putenv(*curr++);
 415         }
 416         if (!(overload & FILE_FIELD) && packet->file[0]) {
 417                 /* watch out for invalid packets */
 418                 *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
 419                 putenv(*curr++);
 420         }
 421         if (!(overload & SNAME_FIELD) && packet->sname[0]) {
 422                 /* watch out for invalid packets */
 423                 *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
 424                 putenv(*curr++);
 425         }
 426
 427         /* Export known DHCP options */
 428         opt_name = dhcp_option_strings;
 429         i = 0;
 430         while (*opt_name) {
 431                 uint8_t code = dhcp_optflags[i].code;
 432                 BITMAP *found_ptr = &FOUND_OPTS(code);
 433                 BITMAP found_mask = BMASK(code);
 434                 if (!(*found_ptr & found_mask))
 435                         goto next;
 436                 *found_ptr &= ~found_mask; /* leave only unknown options */
 437                 temp = udhcp_get_option(packet, code);
 438                 *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name);
 439                 putenv(*curr++);
 440                 if (code == DHCP_SUBNET) {
 441                         /* Subnet option: make things like "$ip/$mask" possible */
 442                         uint32_t subnet;
 443                         move_from_unaligned32(subnet, temp);
 444                         *curr = xasprintf("mask=%u", mton(subnet));
 445                         putenv(*curr++);
 446                 }
 447  next:
 448                 opt_name += strlen(opt_name) + 1;
 449                 i++;
 450         }
 451         /* Export unknown options */
 452         for (i = 0; i < 256;) {
 453                 BITMAP bitmap = FOUND_OPTS(i);
 454                 if (!bitmap) {
 455                         i += BBITS;
 456                         continue;
 457                 }
 458                 if (bitmap & BMASK(i)) {
 459                         unsigned len, ofs;
 460
 461                         temp = udhcp_get_option(packet, i);
 462                         /* udhcp_get_option returns ptr to data portion,
 463                          * need to go back to get len
 464                          */
 465                         len = temp[-OPT_DATA + OPT_LEN];
 466                         *curr = xmalloc(sizeof("optNNN=") + 1 + len*2);
 467                         ofs = sprintf(*curr, "opt%u=", i);
 468                         *bin2hex(*curr + ofs, (void*) temp, len) = '\0';
 469                         putenv(*curr++);
 470                 }
 471                 i++;
 472         }
 473
 474         return envp;
 475 }
 476
 477 /* Call a script with a par file and env vars */
 478 static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
 479 {
 480         char **envp, **curr;
 481         char *argv[3];
 482
 483         envp = fill_envp(packet);
 484
 485         /* call script */
 486         log1("Executing %s %s", client_config.script, name);
 487         argv[0] = (char*) client_config.script;
 488         argv[1] = (char*) name;
 489         argv[2] = NULL;
 490         spawn_and_wait(argv);
 491
 492         for (curr = envp; *curr; curr++) {
 493                 log2(" %s", *curr);
 494                 bb_unsetenv_and_free(*curr);
 495         }
 496         free(envp);
 497 }
 498
 499
 500 /*** Sending/receiving packets ***/
 501
 502 static ALWAYS_INLINE uint32_t random_xid(void)
 503 {
 504         return rand();
 505 }
 506
 507 /* Initialize the packet with the proper defaults */
 508 static void init_packet(struct dhcp_packet *packet, char type)
 509 {
 510         uint16_t secs;
 511
 512         /* Fill in: op, htype, hlen, cookie fields; message type option: */
 513         udhcp_init_header(packet, type);
 514
 515         packet->xid = random_xid();
 516
 517         client_config.last_secs = monotonic_sec();
 518         if (client_config.first_secs == 0)
 519                 client_config.first_secs = client_config.last_secs;
 520         secs = client_config.last_secs - client_config.first_secs;
 521         packet->secs = htons(secs);
 522
 523         memcpy(packet->chaddr, client_config.client_mac, 6);
 524         if (client_config.clientid)
 525                 udhcp_add_binary_option(packet, client_config.clientid);
 526 }
 527
 528 static void add_client_options(struct dhcp_packet *packet)
 529 {
 530         uint8_t c;
 531         int i, end, len;
 532
 533         udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
 534
 535         /* Add a "param req" option with the list of options we'd like to have
 536          * from stubborn DHCP servers. Pull the data from the struct in common.c.
 537          * No bounds checking because it goes towards the head of the packet. */
 538         end = udhcp_end_option(packet->options);
 539         len = 0;
 540         for (i = 0; (c = dhcp_optflags[i].code) != 0; i++) {
 541                 if ((   (dhcp_optflags[i].flags & OPTION_REQ)
 542                      && !client_config.no_default_options
 543                     )
 544                  || (client_config.opt_mask[c >> 3] & (1 << (c & 7)))
 545                 ) {
 546                         packet->options[end + OPT_DATA + len] = c;
 547                         len++;
 548                 }
 549         }
 550         if (len) {
 551                 packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
 552                 packet->options[end + OPT_LEN] = len;
 553                 packet->options[end + OPT_DATA + len] = DHCP_END;
 554         }
 555
 556         if (client_config.vendorclass)
 557                 udhcp_add_binary_option(packet, client_config.vendorclass);
 558         if (client_config.hostname)
 559                 udhcp_add_binary_option(packet, client_config.hostname);
 560         if (client_config.fqdn)
 561                 udhcp_add_binary_option(packet, client_config.fqdn);
 562
 563         /* Request broadcast replies if we have no IP addr */
 564         if ((option_mask32 & OPT_B) && packet->ciaddr == 0)
 565                 packet->flags |= htons(BROADCAST_FLAG);
 566
 567         /* Add -x options if any */
 568         {
 569                 struct option_set *curr = client_config.options;
 570                 while (curr) {
 571                         udhcp_add_binary_option(packet, curr->data);
 572                         curr = curr->next;
 573                 }
 574 //              if (client_config.sname)
 575 //                      strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
 576 //              if (client_config.boot_file)
 577 //                      strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
 578         }
 579
 580         // This will be needed if we remove -V VENDOR_STR in favor of
 581         // -x vendor:VENDOR_STR
 582         //if (!udhcp_find_option(packet.options, DHCP_VENDOR))
 583         //      /* not set, set the default vendor ID */
 584         //      ...add (DHCP_VENDOR, "udhcp "BB_VER) opt...
 585 }
 586
 587 /* RFC 2131
 588  * 4.4.4 Use of broadcast and unicast
 589  *
 590  * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
 591  * messages, unless the client knows the address of a DHCP server.
 592  * The client unicasts DHCPRELEASE messages to the server. Because
 593  * the client is declining the use of the IP address supplied by the server,
 594  * the client broadcasts DHCPDECLINE messages.
 595  *
 596  * When the DHCP client knows the address of a DHCP server, in either
 597  * INIT or REBOOTING state, the client may use that address
 598  * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
 599  * The client may also use unicast to send DHCPINFORM messages
 600  * to a known DHCP server. If the client receives no response to DHCP
 601  * messages sent to the IP address of a known DHCP server, the DHCP
 602  * client reverts to using the IP broadcast address.
 603  */
 604
 605 static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet)
 606 {
 607         return udhcp_send_raw_packet(packet,
 608                 /*src*/ INADDR_ANY, CLIENT_PORT,
 609                 /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
 610                 client_config.ifindex);
 611 }
 612
 613 /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
 614 /* NOINLINE: limit stack usage in caller */
 615 static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
 616 {
 617         struct dhcp_packet packet;
 618
 619         /* Fill in: op, htype, hlen, cookie, chaddr fields,
 620          * random xid field (we override it below),
 621          * client-id option (unless -C), message type option:
 622          */
 623         init_packet(&packet, DHCPDISCOVER);
 624
 625         packet.xid = xid;
 626         if (requested)
 627                 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
 628
 629         /* Add options: maxsize,
 630          * optionally: hostname, fqdn, vendorclass,
 631          * "param req" option according to -O, options specified with -x
 632          */
 633         add_client_options(&packet);
 634
 635         bb_info_msg("Sending discover...");
 636         return raw_bcast_from_client_config_ifindex(&packet);
 637 }
 638
 639 /* Broadcast a DHCP request message */
 640 /* RFC 2131 3.1 paragraph 3:
 641  * "The client _broadcasts_ a DHCPREQUEST message..."
 642  */
 643 /* NOINLINE: limit stack usage in caller */
 644 static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
 645 {
 646         struct dhcp_packet packet;
 647         struct in_addr addr;
 648
 649 /*
 650  * RFC 2131 4.3.2 DHCPREQUEST message
 651  * ...
 652  * If the DHCPREQUEST message contains a 'server identifier'
 653  * option, the message is in response to a DHCPOFFER message.
 654  * Otherwise, the message is a request to verify or extend an
 655  * existing lease. If the client uses a 'client identifier'
 656  * in a DHCPREQUEST message, it MUST use that same 'client identifier'
 657  * in all subsequent messages. If the client included a list
 658  * of requested parameters in a DHCPDISCOVER message, it MUST
 659  * include that list in all subsequent messages.
 660  */
 661         /* Fill in: op, htype, hlen, cookie, chaddr fields,
 662          * random xid field (we override it below),
 663          * client-id option (unless -C), message type option:
 664          */
 665         init_packet(&packet, DHCPREQUEST);
 666
 667         packet.xid = xid;
 668         udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
 669
 670         udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
 671
 672         /* Add options: maxsize,
 673          * optionally: hostname, fqdn, vendorclass,
 674          * "param req" option according to -O, and options specified with -x
 675          */
 676         add_client_options(&packet);
 677
 678         addr.s_addr = requested;
 679         bb_info_msg("Sending select for %s...", inet_ntoa(addr));
 680         return raw_bcast_from_client_config_ifindex(&packet);
 681 }
 682
 683 /* Unicast or broadcast a DHCP renew message */
 684 /* NOINLINE: limit stack usage in caller */
 685 static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
 686 {
 687         struct dhcp_packet packet;
 688
 689 /*
 690  * RFC 2131 4.3.2 DHCPREQUEST message
 691  * ...
 692  * DHCPREQUEST generated during RENEWING state:
 693  *
 694  * 'server identifier' MUST NOT be filled in, 'requested IP address'
 695  * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
 696  * client's IP address. In this situation, the client is completely
 697  * configured, and is trying to extend its lease. This message will
 698  * be unicast, so no relay agents will be involved in its
 699  * transmission.  Because 'giaddr' is therefore not filled in, the
 700  * DHCP server will trust the value in 'ciaddr', and use it when
 701  * replying to the client.
 702  */
 703         /* Fill in: op, htype, hlen, cookie, chaddr fields,
 704          * random xid field (we override it below),
 705          * client-id option (unless -C), message type option:
 706          */
 707         init_packet(&packet, DHCPREQUEST);
 708
 709         packet.xid = xid;
 710         packet.ciaddr = ciaddr;
 711
 712         /* Add options: maxsize,
 713          * optionally: hostname, fqdn, vendorclass,
 714          * "param req" option according to -O, and options specified with -x
 715          */
 716         add_client_options(&packet);
 717
 718         bb_info_msg("Sending renew...");
 719         if (server)
 720                 return udhcp_send_kernel_packet(&packet,
 721                         ciaddr, CLIENT_PORT,
 722                         server, SERVER_PORT);
 723         return raw_bcast_from_client_config_ifindex(&packet);
 724 }
 725
 726 #if ENABLE_FEATURE_UDHCPC_ARPING
 727 /* Broadcast a DHCP decline message */
 728 /* NOINLINE: limit stack usage in caller */
 729 static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
 730 {
 731         struct dhcp_packet packet;
 732
 733         /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
 734          * client-id option (unless -C), message type option:
 735          */
 736         init_packet(&packet, DHCPDECLINE);
 737
 738 #if 0
 739         /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
 740          * but in case the server is buggy and wants DHCPDECLINE's xid
 741          * to match the xid which started entire handshake,
 742          * we use the same xid we used in initial DHCPDISCOVER:
 743          */
 744         packet.xid = xid;
 745 #endif
 746         /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
 747         udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
 748
 749         udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
 750
 751         bb_info_msg("Sending decline...");
 752         return raw_bcast_from_client_config_ifindex(&packet);
 753 }
 754 #endif
 755
 756 /* Unicast a DHCP release message */
 757 static int send_release(uint32_t server, uint32_t ciaddr)
 758 {
 759         struct dhcp_packet packet;
 760
 761         /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
 762          * client-id option (unless -C), message type option:
 763          */
 764         init_packet(&packet, DHCPRELEASE);
 765
 766         /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
 767         packet.ciaddr = ciaddr;
 768
 769         udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
 770
 771         bb_info_msg("Sending release...");
 772         return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
 773 }
 774
 775 /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
 776 /* NOINLINE: limit stack usage in caller */
 777 static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
 778 {
 779         int bytes;
 780         struct ip_udp_dhcp_packet packet;
 781         uint16_t check;
 782
 783         bytes = safe_read(fd, &packet, sizeof(packet));
 784         if (bytes < 0) {
 785                 log1("Packet read error, ignoring");
 786                 /* NB: possible down interface, etc. Caller should pause. */
 787                 return bytes; /* returns -1 */
 788         }
 789
 790         if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
 791                 log1("Packet is too short, ignoring");
 792                 return -2;
 793         }
 794
 795         if (bytes < ntohs(packet.ip.tot_len)) {
 796                 /* packet is bigger than sizeof(packet), we did partial read */
 797                 log1("Oversized packet, ignoring");
 798                 return -2;
 799         }
 800
 801         /* ignore any extra garbage bytes */
 802         bytes = ntohs(packet.ip.tot_len);
 803
 804         /* make sure its the right packet for us, and that it passes sanity checks */
 805         if (packet.ip.protocol != IPPROTO_UDP
 806          || packet.ip.version != IPVERSION
 807          || packet.ip.ihl != (sizeof(packet.ip) >> 2)
 808          || packet.udp.dest != htons(CLIENT_PORT)
 809         /* || bytes > (int) sizeof(packet) - can't happen */
 810          || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
 811         ) {
 812                 log1("Unrelated/bogus packet, ignoring");
 813                 return -2;
 814         }
 815
 816         /* verify IP checksum */
 817         check = packet.ip.check;
 818         packet.ip.check = 0;
 819         if (check != inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip))) {
 820                 log1("Bad IP header checksum, ignoring");
 821                 return -2;
 822         }
 823
 824         /* verify UDP checksum. IP header has to be modified for this */
 825         memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
 826         /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
 827         packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
 828         check = packet.udp.check;
 829         packet.udp.check = 0;
 830         if (check && check != inet_cksum((uint16_t *)&packet, bytes)) {
 831                 log1("Packet with bad UDP checksum received, ignoring");
 832                 return -2;
 833         }
 834
 835         if (packet.data.cookie != htonl(DHCP_MAGIC)) {
 836                 bb_info_msg("Packet with bad magic, ignoring");
 837                 return -2;
 838         }
 839
 840         log1("Received a packet");
 841         udhcp_dump_packet(&packet.data);
 842
 843         bytes -= sizeof(packet.ip) + sizeof(packet.udp);
 844         memcpy(dhcp_pkt, &packet.data, bytes);
 845         return bytes;
 846 }
 847
 848
 849 /*** Main ***/
 850
 851 static int sockfd = -1;
 852
 853 #define LISTEN_NONE   0
 854 #define LISTEN_KERNEL 1
 855 #define LISTEN_RAW    2
 856 static smallint listen_mode;
 857
 858 /* initial state: (re)start DHCP negotiation */
 859 #define INIT_SELECTING  0
 860 /* discover was sent, DHCPOFFER reply received */
 861 #define REQUESTING      1
 862 /* select/renew was sent, DHCPACK reply received */
 863 #define BOUND           2
 864 /* half of lease passed, want to renew it by sending unicast renew requests */
 865 #define RENEWING        3
 866 /* renew requests were not answered, lease is almost over, send broadcast renew */
 867 #define REBINDING       4
 868 /* manually requested renew (SIGUSR1) */
 869 #define RENEW_REQUESTED 5
 870 /* release, possibly manually requested (SIGUSR2) */
 871 #define RELEASED        6
 872 static smallint state;
 873
 874 static int udhcp_raw_socket(int ifindex)
 875 {
 876         int fd;
 877         struct sockaddr_ll sock;
 878
 879         /*
 880          * Comment:
 881          *
 882          *      I've selected not to see LL header, so BPF doesn't see it, too.
 883          *      The filter may also pass non-IP and non-ARP packets, but we do
 884          *      a more complete check when receiving the message in userspace.
 885          *
 886          * and filter shamelessly stolen from:
 887          *
 888          *      http://www.flamewarmaster.de/software/dhcpclient/
 889          *
 890          * There are a few other interesting ideas on that page (look under
 891          * "Motivation").  Use of netlink events is most interesting.  Think
 892          * of various network servers listening for events and reconfiguring.
 893          * That would obsolete sending HUP signals and/or make use of restarts.
 894          *
 895          * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
 896          * License: GPL v2.
 897          *
 898          * TODO: make conditional?
 899          */
 900         static const struct sock_filter filter_instr[] = {
 901                 /* load 9th byte (protocol) */
 902                 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
 903                 /* jump to L1 if it is IPPROTO_UDP, else to L4 */
 904                 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
 905                 /* L1: load halfword from offset 6 (flags and frag offset) */
 906                 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
 907                 /* jump to L4 if any bits in frag offset field are set, else to L2 */
 908                 BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
 909                 /* L2: skip IP header (load index reg with header len) */
 910                 BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
 911                 /* load udp destination port from halfword[header_len + 2] */
 912                 BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
 913                 /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
 914                 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
 915                 /* L3: accept packet */
 916                 BPF_STMT(BPF_RET|BPF_K, 0xffffffff),
 917                 /* L4: discard packet */
 918                 BPF_STMT(BPF_RET|BPF_K, 0),
 919         };
 920         static const struct sock_fprog filter_prog = {
 921                 .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
 922                 /* casting const away: */
 923                 .filter = (struct sock_filter *) filter_instr,
 924         };
 925
 926         log1("Opening raw socket on ifindex %d", ifindex); //log2?
 927
 928         fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
 929         log1("Got raw socket fd %d", fd); //log2?
 930
 931         sock.sll_family = AF_PACKET;
 932         sock.sll_protocol = htons(ETH_P_IP);
 933         sock.sll_ifindex = ifindex;
 934         xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
 935
 936         if (CLIENT_PORT == 68) {
 937                 /* Use only if standard port is in use */
 938                 /* Ignoring error (kernel may lack support for this) */
 939                 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
 940                                 sizeof(filter_prog)) >= 0)
 941                         log1("Attached filter to raw socket fd %d", fd); // log?
 942         }
 943
 944         log1("Created raw socket");
 945
 946         return fd;
 947 }
 948
 949 static void change_listen_mode(int new_mode)
 950 {
 951         log1("Entering listen mode: %s",
 952                 new_mode != LISTEN_NONE
 953                         ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
 954                         : "none"
 955         );
 956
 957         listen_mode = new_mode;
 958         if (sockfd >= 0) {
 959                 close(sockfd);
 960                 sockfd = -1;
 961         }
 962         if (new_mode == LISTEN_KERNEL)
 963                 sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
 964         else if (new_mode != LISTEN_NONE)
 965                 sockfd = udhcp_raw_socket(client_config.ifindex);
 966         /* else LISTEN_NONE: sockfd stays closed */
 967 }
 968
 969 /* Called only on SIGUSR1 */
 970 static void perform_renew(void)
 971 {
 972         bb_info_msg("Performing a DHCP renew");
 973         switch (state) {
 974         case BOUND:
 975                 change_listen_mode(LISTEN_KERNEL);
 976         case RENEWING:
 977         case REBINDING:
 978                 state = RENEW_REQUESTED;
 979                 break;
 980         case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
 981                 udhcp_run_script(NULL, "deconfig");
 982         case REQUESTING:
 983         case RELEASED:
 984                 change_listen_mode(LISTEN_RAW);
 985                 state = INIT_SELECTING;
 986                 break;
 987         case INIT_SELECTING:
 988                 break;
 989         }
 990 }
 991
 992 static void perform_release(uint32_t server_addr, uint32_t requested_ip)
 993 {
 994         char buffer[sizeof("255.255.255.255")];
 995         struct in_addr temp_addr;
 996
 997         /* send release packet */
 998         if (state == BOUND || state == RENEWING || state == REBINDING) {
 999                 temp_addr.s_addr = server_addr;
1000                 strcpy(buffer, inet_ntoa(temp_addr));
1001                 temp_addr.s_addr = requested_ip;
1002                 bb_info_msg("Unicasting a release of %s to %s",
1003                                 inet_ntoa(temp_addr), buffer);
1004                 send_release(server_addr, requested_ip); /* unicast */
1005                 udhcp_run_script(NULL, "deconfig");
1006         }
1007         bb_info_msg("Entering released state");
1008
1009         change_listen_mode(LISTEN_NONE);
1010         state = RELEASED;
1011 }
1012
1013 static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
1014 {
1015         uint8_t *storage;
1016         int len = strnlen(str, 255);
1017         storage = xzalloc(len + extra + OPT_DATA);
1018         storage[OPT_CODE] = code;
1019         storage[OPT_LEN] = len + extra;
1020         memcpy(storage + extra + OPT_DATA, str, len);
1021         return storage;
1022 }
1023
1024 #if BB_MMU
1025 static void client_background(void)
1026 {
1027         bb_daemonize(0);
1028         logmode &= ~LOGMODE_STDIO;
1029         /* rewrite pidfile, as our pid is different now */
1030         write_pidfile(client_config.pidfile);
1031 }
1032 #endif
1033
1034 //usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
1035 //usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
1036 //usage:#else
1037 //usage:# define IF_UDHCP_VERBOSE(...)
1038 //usage:#endif
1039 //usage:#define udhcpc_trivial_usage
1040 //usage:       "[-fbnq"IF_UDHCP_VERBOSE("v")"oCRB] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]\n"
1041 //usage:       "        [-V VENDOR] [-x OPT:VAL]... [-O OPT]..." IF_FEATURE_UDHCP_PORT(" [-P N]")
1042 //usage:#define udhcpc_full_usage "\n"
1043 //usage:        IF_LONG_OPTS(
1044 //usage:     "\n        -i,--interface IFACE    Interface to use (default eth0)"
1045 //usage:     "\n        -p,--pidfile FILE       Create pidfile"
1046 //usage:     "\n        -s,--script PROG        Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
1047 //usage:     "\n        -B,--broadcast          Request broadcast replies"
1048 //usage:     "\n        -t,--retries N          Send up to N discover packets"
1049 //usage:     "\n        -T,--timeout N          Pause between packets (default 3 seconds)"
1050 //usage:     "\n        -A,--tryagain N         Wait N seconds after failure (default 20)"
1051 //usage:     "\n        -f,--foreground         Run in foreground"
1052 //usage:        USE_FOR_MMU(
1053 //usage:     "\n        -b,--background         Background if lease is not obtained"
1054 //usage:        )
1055 //usage:     "\n        -n,--now                Exit if lease is not obtained"
1056 //usage:     "\n        -q,--quit               Exit after obtaining lease"
1057 //usage:     "\n        -R,--release            Release IP on exit"
1058 //usage:     "\n        -S,--syslog             Log to syslog too"
1059 //usage:        IF_FEATURE_UDHCP_PORT(
1060 //usage:     "\n        -P,--client-port N      Use port N (default 68)"
1061 //usage:        )
1062 //usage:        IF_FEATURE_UDHCPC_ARPING(
1063 //usage:     "\n        -a,--arping             Use arping to validate offered address"
1064 //usage:        )
1065 //usage:     "\n        -O,--request-option OPT Request option OPT from server (cumulative)"
1066 //usage:     "\n        -o,--no-default-options Don't request any options (unless -O is given)"
1067 //usage:     "\n        -r,--request IP         Request this IP address"
1068 //usage:     "\n        -x OPT:VAL              Include option OPT in sent packets (cumulative)"
1069 //usage:     "\n                                Examples of string, numeric, and hex byte opts:"
1070 //usage:     "\n                                -x hostname:bbox - option 12"
1071 //usage:     "\n                                -x lease:3600 - option 51 (lease time)"
1072 //usage:     "\n                                -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
1073 //usage:     "\n        -F,--fqdn NAME          Ask server to update DNS mapping for NAME"
1074 //usage:     "\n        -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')"
1075 //usage:     "\n        -C,--clientid-none      Don't send MAC as client identifier"
1076 //usage:        IF_UDHCP_VERBOSE(
1077 //usage:     "\n        -v                      Verbose"
1078 //usage:        )
1079 //usage:        )
1080 //usage:        IF_NOT_LONG_OPTS(
1081 //usage:     "\n        -i IFACE        Interface to use (default eth0)"
1082 //usage:     "\n        -p FILE         Create pidfile"
1083 //usage:     "\n        -s PROG         Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
1084 //usage:     "\n        -B              Request broadcast replies"
1085 //usage:     "\n        -t N            Send up to N discover packets"
1086 //usage:     "\n        -T N            Pause between packets (default 3 seconds)"
1087 //usage:     "\n        -A N            Wait N seconds (default 20) after failure"
1088 //usage:     "\n        -f              Run in foreground"
1089 //usage:        USE_FOR_MMU(
1090 //usage:     "\n        -b              Background if lease is not obtained"
1091 //usage:        )
1092 //usage:     "\n        -n              Exit if lease is not obtained"
1093 //usage:     "\n        -q              Exit after obtaining lease"
1094 //usage:     "\n        -R              Release IP on exit"
1095 //usage:     "\n        -S              Log to syslog too"
1096 //usage:        IF_FEATURE_UDHCP_PORT(
1097 //usage:     "\n        -P N            Use port N (default 68)"
1098 //usage:        )
1099 //usage:        IF_FEATURE_UDHCPC_ARPING(
1100 //usage:     "\n        -a              Use arping to validate offered address"
1101 //usage:        )
1102 //usage:     "\n        -O OPT          Request option OPT from server (cumulative)"
1103 //usage:     "\n        -o              Don't request any options (unless -O is given)"
1104 //usage:     "\n        -r IP           Request this IP address"
1105 //usage:     "\n        -x OPT:VAL      Include option OPT in sent packets (cumulative)"
1106 //usage:     "\n                        Examples of string, numeric, and hex byte opts:"
1107 //usage:     "\n                        -x hostname:bbox - option 12"
1108 //usage:     "\n                        -x lease:3600 - option 51 (lease time)"
1109 //usage:     "\n                        -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
1110 //usage:     "\n        -F NAME         Ask server to update DNS mapping for NAME"
1111 //usage:     "\n        -V VENDOR       Vendor identifier (default 'udhcp VERSION')"
1112 //usage:     "\n        -C              Don't send MAC as client identifier"
1113 //usage:        IF_UDHCP_VERBOSE(
1114 //usage:     "\n        -v              Verbose"
1115 //usage:        )
1116 //usage:        )
1117 //usage:     "\nSignals:"
1118 //usage:     "\n        USR1    Renew lease"
1119 //usage:     "\n        USR2    Release lease"
1120
1121
1122 int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1123 int udhcpc_main(int argc UNUSED_PARAM, char **argv)
1124 {
1125         uint8_t *temp, *message;
1126         const char *str_V, *str_h, *str_F, *str_r;
1127         IF_FEATURE_UDHCP_PORT(char *str_P;)
1128         void *clientid_mac_ptr;
1129         llist_t *list_O = NULL;
1130         llist_t *list_x = NULL;
1131         int tryagain_timeout = 20;
1132         int discover_timeout = 3;
1133         int discover_retries = 3;
1134         uint32_t server_addr = server_addr; /* for compiler */
1135         uint32_t requested_ip = 0;
1136         uint32_t xid = xid; /* for compiler */
1137         int packet_num;
1138         int timeout; /* must be signed */
1139         unsigned already_waited_sec;
1140         unsigned opt;
1141         int max_fd;
1142         int retval;
1143         fd_set rfds;
1144
1145         /* Default options */
1146         IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
1147         IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
1148         client_config.interface = "eth0";
1149         client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
1150         str_V = "udhcp "BB_VER;
1151
1152         /* Parse command line */
1153         /* O,x: list; -T,-t,-A take numeric param */
1154         opt_complementary = "O::x::T+:t+:A+" IF_UDHCP_VERBOSE(":vv") ;
1155         IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
1156         opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:fB"
1157                 USE_FOR_MMU("b")
1158                 IF_FEATURE_UDHCPC_ARPING("a")
1159                 IF_FEATURE_UDHCP_PORT("P:")
1160                 "v"
1161                 , &str_V, &str_h, &str_h, &str_F
1162                 , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
1163                 , &client_config.script /* s */
1164                 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
1165                 , &list_O
1166                 , &list_x
1167                 IF_FEATURE_UDHCP_PORT(, &str_P)
1168                 IF_UDHCP_VERBOSE(, &dhcp_verbose)
1169         );
1170         if (opt & (OPT_h|OPT_H)) {
1171                 //msg added 2011-11
1172                 bb_error_msg("option -h NAME is deprecated, use -x hostname:NAME");
1173                 client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
1174         }
1175         if (opt & OPT_F) {
1176                 /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
1177                 client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
1178                 /* Flag bits: 0000NEOS
1179                  * S: 1 = Client requests server to update A RR in DNS as well as PTR
1180                  * O: 1 = Server indicates to client that DNS has been updated regardless
1181                  * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
1182                  *    not "host.domain.com". Format 0 is obsolete.
1183                  * N: 1 = Client requests server to not update DNS (S must be 0 then)
1184                  * Two [0] bytes which follow are deprecated and must be 0.
1185                  */
1186                 client_config.fqdn[OPT_DATA + 0] = 0x1;
1187                 /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
1188                 /*client_config.fqdn[OPT_DATA + 2] = 0; */
1189         }
1190         if (opt & OPT_r)
1191                 requested_ip = inet_addr(str_r);
1192 #if ENABLE_FEATURE_UDHCP_PORT
1193         if (opt & OPT_P) {
1194                 CLIENT_PORT = xatou16(str_P);
1195                 SERVER_PORT = CLIENT_PORT - 1;
1196         }
1197 #endif
1198         if (opt & OPT_o)
1199                 client_config.no_default_options = 1;
1200         while (list_O) {
1201                 char *optstr = llist_pop(&list_O);
1202                 unsigned n = bb_strtou(optstr, NULL, 0);
1203                 if (errno || n > 254) {
1204                         n = udhcp_option_idx(optstr);
1205                         n = dhcp_optflags[n].code;
1206                 }
1207                 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
1208         }
1209         while (list_x) {
1210                 char *optstr = llist_pop(&list_x);
1211                 char *colon = strchr(optstr, ':');
1212                 if (colon)
1213                         *colon = ' ';
1214                 /* now it looks similar to udhcpd's config file line:
1215                  * "optname optval", using the common routine: */
1216                 udhcp_str2optset(optstr, &client_config.options);
1217         }
1218
1219         if (udhcp_read_interface(client_config.interface,
1220                         &client_config.ifindex,
1221                         NULL,
1222                         client_config.client_mac)
1223         ) {
1224                 return 1;
1225         }
1226
1227         clientid_mac_ptr = NULL;
1228         if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) {
1229                 /* not suppressed and not set, set the default client ID */
1230                 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
1231                 client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
1232                 clientid_mac_ptr = client_config.clientid + OPT_DATA+1;
1233                 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1234         }
1235         if (str_V[0] != '\0') {
1236                 // can drop -V, str_V, client_config.vendorclass,
1237                 // but need to add "vendor" to the list of recognized
1238                 // string opts for this to work;
1239                 // and need to tweak add_client_options() too...
1240                 // ...so the question is, should we?
1241                 //bb_error_msg("option -V VENDOR is deprecated, use -x vendor:VENDOR");
1242                 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
1243         }
1244
1245 #if !BB_MMU
1246         /* on NOMMU reexec (i.e., background) early */
1247         if (!(opt & OPT_f)) {
1248                 bb_daemonize_or_rexec(0 /* flags */, argv);
1249                 logmode = LOGMODE_NONE;
1250         }
1251 #endif
1252         if (opt & OPT_S) {
1253                 openlog(applet_name, LOG_PID, LOG_DAEMON);
1254                 logmode |= LOGMODE_SYSLOG;
1255         }
1256
1257         /* Make sure fd 0,1,2 are open */
1258         bb_sanitize_stdio();
1259         /* Equivalent of doing a fflush after every \n */
1260         setlinebuf(stdout);
1261         /* Create pidfile */
1262         write_pidfile(client_config.pidfile);
1263         /* Goes to stdout (unless NOMMU) and possibly syslog */
1264         bb_info_msg("%s (v"BB_VER") started", applet_name);
1265         /* Set up the signal pipe */
1266         udhcp_sp_setup();
1267         /* We want random_xid to be random... */
1268         srand(monotonic_us());
1269
1270         state = INIT_SELECTING;
1271         udhcp_run_script(NULL, "deconfig");
1272         change_listen_mode(LISTEN_RAW);
1273         packet_num = 0;
1274         timeout = 0;
1275         already_waited_sec = 0;
1276
1277         /* Main event loop. select() waits on signal pipe and possibly
1278          * on sockfd.
1279          * "continue" statements in code below jump to the top of the loop.
1280          */
1281         for (;;) {
1282                 struct timeval tv;
1283                 struct dhcp_packet packet;
1284                 /* silence "uninitialized!" warning */
1285                 unsigned timestamp_before_wait = timestamp_before_wait;
1286
1287                 //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
1288
1289                 /* Was opening raw or udp socket here
1290                  * if (listen_mode != LISTEN_NONE && sockfd < 0),
1291                  * but on fast network renew responses return faster
1292                  * than we open sockets. Thus this code is moved
1293                  * to change_listen_mode(). Thus we open listen socket
1294                  * BEFORE we send renew request (see "case BOUND:"). */
1295
1296                 max_fd = udhcp_sp_fd_set(&rfds, sockfd);
1297
1298                 tv.tv_sec = timeout - already_waited_sec;
1299                 tv.tv_usec = 0;
1300                 retval = 0;
1301                 /* If we already timed out, fall through with retval = 0, else... */
1302                 if ((int)tv.tv_sec > 0) {
1303                         timestamp_before_wait = (unsigned)monotonic_sec();
1304                         log1("Waiting on select...");
1305                         retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
1306                         if (retval < 0) {
1307                                 /* EINTR? A signal was caught, don't panic */
1308                                 if (errno == EINTR) {
1309                                         already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1310                                         continue;
1311                                 }
1312                                 /* Else: an error occured, panic! */
1313                                 bb_perror_msg_and_die("select");
1314                         }
1315                 }
1316
1317                 /* If timeout dropped to zero, time to become active:
1318                  * resend discover/renew/whatever
1319                  */
1320                 if (retval == 0) {
1321                         /* When running on a bridge, the ifindex may have changed
1322                          * (e.g. if member interfaces were added/removed
1323                          * or if the status of the bridge changed).
1324                          * Refresh ifindex and client_mac:
1325                          */
1326                         if (udhcp_read_interface(client_config.interface,
1327                                         &client_config.ifindex,
1328                                         NULL,
1329                                         client_config.client_mac)
1330                         ) {
1331                                 goto ret0; /* iface is gone? */
1332                         }
1333                         if (clientid_mac_ptr)
1334                                 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1335
1336                         /* We will restart the wait in any case */
1337                         already_waited_sec = 0;
1338
1339                         switch (state) {
1340                         case INIT_SELECTING:
1341                                 if (packet_num < discover_retries) {
1342                                         if (packet_num == 0)
1343                                                 xid = random_xid();
1344                                         /* broadcast */
1345                                         send_discover(xid, requested_ip);
1346                                         timeout = discover_timeout;
1347                                         packet_num++;
1348                                         continue;
1349                                 }
1350  leasefail:
1351                                 udhcp_run_script(NULL, "leasefail");
1352 #if BB_MMU /* -b is not supported on NOMMU */
1353                                 if (opt & OPT_b) { /* background if no lease */
1354                                         bb_info_msg("No lease, forking to background");
1355                                         client_background();
1356                                         /* do not background again! */
1357                                         opt = ((opt & ~OPT_b) | OPT_f);
1358                                 } else
1359 #endif
1360                                 if (opt & OPT_n) { /* abort if no lease */
1361                                         bb_info_msg("No lease, failing");
1362                                         retval = 1;
1363                                         goto ret;
1364                                 }
1365                                 /* wait before trying again */
1366                                 timeout = tryagain_timeout;
1367                                 packet_num = 0;
1368                                 continue;
1369                         case REQUESTING:
1370                                 if (packet_num < discover_retries) {
1371                                         /* send broadcast select packet */
1372                                         send_select(xid, server_addr, requested_ip);
1373                                         timeout = discover_timeout;
1374                                         packet_num++;
1375                                         continue;
1376                                 }
1377                                 /* Timed out, go back to init state.
1378                                  * "discover...select...discover..." loops
1379                                  * were seen in the wild. Treat them similarly
1380                                  * to "no response to discover" case */
1381                                 change_listen_mode(LISTEN_RAW);
1382                                 state = INIT_SELECTING;
1383                                 goto leasefail;
1384                         case BOUND:
1385                                 /* 1/2 lease passed, enter renewing state */
1386                                 state = RENEWING;
1387                                 client_config.first_secs = 0; /* make secs field count from 0 */
1388                                 change_listen_mode(LISTEN_KERNEL);
1389                                 log1("Entering renew state");
1390                                 /* fall right through */
1391                         case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
1392                         case_RENEW_REQUESTED:
1393                         case RENEWING:
1394                                 if (timeout > 60) {
1395                                         /* send an unicast renew request */
1396                         /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1397                          * a new UDP socket for sending inside send_renew.
1398                          * I hazard to guess existing listening socket
1399                          * is somehow conflicting with it, but why is it
1400                          * not deterministic then?! Strange.
1401                          * Anyway, it does recover by eventually failing through
1402                          * into INIT_SELECTING state.
1403                          */
1404                                         send_renew(xid, server_addr, requested_ip);
1405                                         timeout >>= 1;
1406                                         continue;
1407                                 }
1408                                 /* Timed out, enter rebinding state */
1409                                 log1("Entering rebinding state");
1410                                 state = REBINDING;
1411                                 /* fall right through */
1412                         case REBINDING:
1413                                 /* Switch to bcast receive */
1414                                 change_listen_mode(LISTEN_RAW);
1415                                 /* Lease is *really* about to run out,
1416                                  * try to find DHCP server using broadcast */
1417                                 if (timeout > 0) {
1418                                         /* send a broadcast renew request */
1419                                         send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
1420                                         timeout >>= 1;
1421                                         continue;
1422                                 }
1423                                 /* Timed out, enter init state */
1424                                 bb_info_msg("Lease lost, entering init state");
1425                                 udhcp_run_script(NULL, "deconfig");
1426                                 state = INIT_SELECTING;
1427                                 client_config.first_secs = 0; /* make secs field count from 0 */
1428                                 /*timeout = 0; - already is */
1429                                 packet_num = 0;
1430                                 continue;
1431                         /* case RELEASED: */
1432                         }
1433                         /* yah, I know, *you* say it would never happen */
1434                         timeout = INT_MAX;
1435                         continue; /* back to main loop */
1436                 } /* if select timed out */
1437
1438                 /* select() didn't timeout, something happened */
1439
1440                 /* Is it a signal? */
1441                 /* note: udhcp_sp_read checks FD_ISSET before reading */
1442                 switch (udhcp_sp_read(&rfds)) {
1443                 case SIGUSR1:
1444                         client_config.first_secs = 0; /* make secs field count from 0 */
1445                         already_waited_sec = 0;
1446                         perform_renew();
1447                         if (state == RENEW_REQUESTED) {
1448                                 /* We might be either on the same network
1449                                  * (in which case renew might work),
1450                                  * or we might be on a completely different one
1451                                  * (in which case renew won't ever succeed).
1452                                  * For the second case, must make sure timeout
1453                                  * is not too big, or else we can send
1454                                  * futile renew requests for hours.
1455                                  * (Ab)use -A TIMEOUT value (usually 20 sec)
1456                                  * as a cap on the timeout.
1457                                  */
1458                                 if (timeout > tryagain_timeout)
1459                                         timeout = tryagain_timeout;
1460                                 goto case_RENEW_REQUESTED;
1461                         }
1462                         /* Start things over */
1463                         packet_num = 0;
1464                         /* Kill any timeouts, user wants this to hurry along */
1465                         timeout = 0;
1466                         continue;
1467                 case SIGUSR2:
1468                         perform_release(server_addr, requested_ip);
1469                         timeout = INT_MAX;
1470                         continue;
1471                 case SIGTERM:
1472                         bb_info_msg("Received SIGTERM");
1473                         goto ret0;
1474                 }
1475
1476                 /* Is it a packet? */
1477                 if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
1478                         continue; /* no */
1479
1480                 {
1481                         int len;
1482
1483                         /* A packet is ready, read it */
1484                         if (listen_mode == LISTEN_KERNEL)
1485                                 len = udhcp_recv_kernel_packet(&packet, sockfd);
1486                         else
1487                                 len = udhcp_recv_raw_packet(&packet, sockfd);
1488                         if (len == -1) {
1489                                 /* Error is severe, reopen socket */
1490                                 bb_info_msg("Read error: %s, reopening socket", strerror(errno));
1491                                 sleep(discover_timeout); /* 3 seconds by default */
1492                                 change_listen_mode(listen_mode); /* just close and reopen */
1493                         }
1494                         /* If this packet will turn out to be unrelated/bogus,
1495                          * we will go back and wait for next one.
1496                          * Be sure timeout is properly decreased. */
1497                         already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1498                         if (len < 0)
1499                                 continue;
1500                 }
1501
1502                 if (packet.xid != xid) {
1503                         log1("xid %x (our is %x), ignoring packet",
1504                                 (unsigned)packet.xid, (unsigned)xid);
1505                         continue;
1506                 }
1507
1508                 /* Ignore packets that aren't for us */
1509                 if (packet.hlen != 6
1510                  || memcmp(packet.chaddr, client_config.client_mac, 6) != 0
1511                 ) {
1512 //FIXME: need to also check that last 10 bytes are zero
1513                         log1("chaddr does not match, ignoring packet"); // log2?
1514                         continue;
1515                 }
1516
1517                 message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
1518                 if (message == NULL) {
1519                         bb_error_msg("no message type option, ignoring packet");
1520                         continue;
1521                 }
1522
1523                 switch (state) {
1524                 case INIT_SELECTING:
1525                         /* Must be a DHCPOFFER */
1526                         if (*message == DHCPOFFER) {
1527 /* What exactly is server's IP? There are several values.
1528  * Example DHCP offer captured with tchdump:
1529  *
1530  * 10.34.25.254:67 > 10.34.25.202:68 // IP header's src
1531  * BOOTP fields:
1532  * Your-IP 10.34.25.202
1533  * Server-IP 10.34.32.125   // "next server" IP
1534  * Gateway-IP 10.34.25.254  // relay's address (if DHCP relays are in use)
1535  * DHCP options:
1536  * DHCP-Message Option 53, length 1: Offer
1537  * Server-ID Option 54, length 4: 10.34.255.7       // "server ID"
1538  * Default-Gateway Option 3, length 4: 10.34.25.254 // router
1539  *
1540  * We think that real server IP (one to use in renew/release)
1541  * is one in Server-ID option. But I am not 100% sure.
1542  * IP header's src and Gateway-IP (same in this example)
1543  * might work too.
1544  * "Next server" and router are definitely wrong ones to use, though...
1545  */
1546                                 temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
1547                                 if (!temp) {
1548                                         bb_error_msg("no server ID, ignoring packet");
1549                                         continue;
1550                                         /* still selecting - this server looks bad */
1551                                 }
1552                                 /* it IS unaligned sometimes, don't "optimize" */
1553                                 move_from_unaligned32(server_addr, temp);
1554                                 /*xid = packet.xid; - already is */
1555                                 requested_ip = packet.yiaddr;
1556
1557                                 /* enter requesting state */
1558                                 state = REQUESTING;
1559                                 timeout = 0;
1560                                 packet_num = 0;
1561                                 already_waited_sec = 0;
1562                         }
1563                         continue;
1564                 case REQUESTING:
1565                 case RENEWING:
1566                 case RENEW_REQUESTED:
1567                 case REBINDING:
1568                         if (*message == DHCPACK) {
1569                                 uint32_t lease_seconds;
1570                                 struct in_addr temp_addr;
1571
1572                                 temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
1573                                 if (!temp) {
1574                                         bb_error_msg("no lease time with ACK, using 1 hour lease");
1575                                         lease_seconds = 60 * 60;
1576                                 } else {
1577                                         /* it IS unaligned sometimes, don't "optimize" */
1578                                         move_from_unaligned32(lease_seconds, temp);
1579                                         lease_seconds = ntohl(lease_seconds);
1580                                         /* paranoia: must not be too small and not prone to overflows */
1581                                         if (lease_seconds < 0x10)
1582                                                 lease_seconds = 0x10;
1583                                         if (lease_seconds >= 0x10000000)
1584                                                 lease_seconds = 0x0fffffff;
1585                                 }
1586 #if ENABLE_FEATURE_UDHCPC_ARPING
1587                                 if (opt & OPT_a) {
1588 /* RFC 2131 3.1 paragraph 5:
1589  * "The client receives the DHCPACK message with configuration
1590  * parameters. The client SHOULD perform a final check on the
1591  * parameters (e.g., ARP for allocated network address), and notes
1592  * the duration of the lease specified in the DHCPACK message. At this
1593  * point, the client is configured. If the client detects that the
1594  * address is already in use (e.g., through the use of ARP),
1595  * the client MUST send a DHCPDECLINE message to the server and restarts
1596  * the configuration process..." */
1597                                         if (!arpping(packet.yiaddr,
1598                                                         NULL,
1599                                                         (uint32_t) 0,
1600                                                         client_config.client_mac,
1601                                                         client_config.interface)
1602                                         ) {
1603                                                 bb_info_msg("Offered address is in use "
1604                                                         "(got ARP reply), declining");
1605                                                 send_decline(/*xid,*/ server_addr, packet.yiaddr);
1606
1607                                                 if (state != REQUESTING)
1608                                                         udhcp_run_script(NULL, "deconfig");
1609                                                 change_listen_mode(LISTEN_RAW);
1610                                                 state = INIT_SELECTING;
1611                                                 client_config.first_secs = 0; /* make secs field count from 0 */
1612                                                 requested_ip = 0;
1613                                                 timeout = tryagain_timeout;
1614                                                 packet_num = 0;
1615                                                 already_waited_sec = 0;
1616                                                 continue; /* back to main loop */
1617                                         }
1618                                 }
1619 #endif
1620                                 /* enter bound state */
1621                                 timeout = lease_seconds / 2;
1622                                 temp_addr.s_addr = packet.yiaddr;
1623                                 bb_info_msg("Lease of %s obtained, lease time %u",
1624                                         inet_ntoa(temp_addr), (unsigned)lease_seconds);
1625                                 requested_ip = packet.yiaddr;
1626                                 udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
1627
1628                                 state = BOUND;
1629                                 change_listen_mode(LISTEN_NONE);
1630                                 if (opt & OPT_q) { /* quit after lease */
1631                                         goto ret0;
1632                                 }
1633                                 /* future renew failures should not exit (JM) */
1634                                 opt &= ~OPT_n;
1635 #if BB_MMU /* NOMMU case backgrounded earlier */
1636                                 if (!(opt & OPT_f)) {
1637                                         client_background();
1638                                         /* do not background again! */
1639                                         opt = ((opt & ~OPT_b) | OPT_f);
1640                                 }
1641 #endif
1642                                 /* make future renew packets use different xid */
1643                                 /* xid = random_xid(); ...but why bother? */
1644                                 already_waited_sec = 0;
1645                                 continue; /* back to main loop */
1646                         }
1647                         if (*message == DHCPNAK) {
1648                                 /* return to init state */
1649                                 bb_info_msg("Received DHCP NAK");
1650                                 udhcp_run_script(&packet, "nak");
1651                                 if (state != REQUESTING)
1652                                         udhcp_run_script(NULL, "deconfig");
1653                                 change_listen_mode(LISTEN_RAW);
1654                                 sleep(3); /* avoid excessive network traffic */
1655                                 state = INIT_SELECTING;
1656                                 client_config.first_secs = 0; /* make secs field count from 0 */
1657                                 requested_ip = 0;
1658                                 timeout = 0;
1659                                 packet_num = 0;
1660                                 already_waited_sec = 0;
1661                         }
1662                         continue;
1663                 /* case BOUND: - ignore all packets */
1664                 /* case RELEASED: - ignore all packets */
1665                 }
1666                 /* back to main loop */
1667         } /* for (;;) - main loop ends */
1668
1669  ret0:
1670         if (opt & OPT_R) /* release on quit */
1671                 perform_release(server_addr, requested_ip);
1672         retval = 0;
1673  ret:
1674         /*if (client_config.pidfile) - remove_pidfile has its own check */
1675                 remove_pidfile(client_config.pidfile);
1676         return retval;
1677 }