networking/udhcpc.c

   1 /* dhcpd.c
   2  *
   3  * udhcp DHCP client
   4  *
   5  * Russ Dill <Russ.Dill@asu.edu> July 2001
   6  *
   7  * Converted to busybox by Glenn McGrath August 2002
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  */
  23
  24 #include <stdio.h>
  25 #include <sys/time.h>
  26 #include <sys/types.h>
  27 #include <sys/file.h>
  28 #include <unistd.h>
  29 #include <getopt.h>
  30 #include <stdlib.h>
  31 #include <sys/socket.h>
  32 #include <netinet/in.h>
  33 #include <arpa/inet.h>
  34 #include <signal.h>
  35 #include <time.h>
  36 #include <string.h>
  37 #include <sys/ioctl.h>
  38 #include <net/if.h>
  39 #include <errno.h>
  40 #include <netinet/ip.h>
  41 #include <netinet/udp.h>
  42 #include <sys/types.h>
  43 #include <sys/wait.h>
  44
  45 #if __GLIBC__ >=2 && __GLIBC_MINOR >= 1
  46 #include <netpacket/packet.h>
  47 #include <net/ethernet.h>
  48 #else
  49 #include <asm/types.h>
  50 #include <linux/if_packet.h>
  51 #include <linux/if_ether.h>
  52 #endif
  53 #include "libbb.h"
  54
  55 static int state;
  56 static unsigned long requested_ip;      /* = 0 */
  57 static unsigned long server_addr;
  58 static unsigned long timeout;
  59 static int packet_num;  /* = 0 */
  60 static int fd_main;
  61
  62 /* #define DEBUG */
  63
  64 #define VERSION "0.9.7"
  65
  66 #define LISTEN_NONE 0
  67 #define LISTEN_KERNEL 1
  68 #define LISTEN_RAW 2
  69 static int listen_mode;
  70
  71 #define DEFAULT_SCRIPT  "/usr/share/udhcpc/default.script"
  72
  73 #define DHCP_END                0xFF
  74 #define TYPE_MASK       0x0F
  75 #define BROADCAST_FLAG          0x8000
  76
  77 #define SERVER_PORT             67
  78
  79 #define DHCP_MAGIC              0x63825363
  80
  81 #define BOOTREQUEST             1
  82 #define BOOTREPLY               2
  83
  84 #define ETH_10MB                1
  85 #define ETH_10MB_LEN            6
  86
  87 #define OPTION_FIELD            0
  88 #define FILE_FIELD              1
  89 #define SNAME_FIELD             2
  90
  91 #define INIT_SELECTING  0
  92 #define REQUESTING      1
  93 #define BOUND           2
  94 #define RENEWING        3
  95 #define REBINDING       4
  96 #define INIT_REBOOT     5
  97 #define RENEW_REQUESTED 6
  98 #define RELEASED        7
  99
 100 #define CLIENT_PORT             68
 101
 102 #define DHCPDISCOVER            1
 103 #define DHCPOFFER               2
 104 #define DHCPREQUEST             3
 105 #define DHCPDECLINE             4
 106 #define DHCPACK                 5
 107 #define DHCPNAK                 6
 108 #define DHCPRELEASE             7
 109 #define DHCPINFORM              8
 110
 111 /* DHCP option codes (partial list) */
 112 #define DHCP_PADDING            0x00
 113 #define DHCP_SUBNET             0x01
 114 #define DHCP_TIME_OFFSET        0x02
 115 #define DHCP_ROUTER             0x03
 116 #define DHCP_TIME_SERVER        0x04
 117 #define DHCP_NAME_SERVER        0x05
 118 #define DHCP_DNS_SERVER         0x06
 119 #define DHCP_LOG_SERVER         0x07
 120 #define DHCP_COOKIE_SERVER      0x08
 121 #define DHCP_LPR_SERVER         0x09
 122 #define DHCP_HOST_NAME          0x0c
 123 #define DHCP_BOOT_SIZE          0x0d
 124 #define DHCP_DOMAIN_NAME        0x0f
 125 #define DHCP_SWAP_SERVER        0x10
 126 #define DHCP_ROOT_PATH          0x11
 127 #define DHCP_IP_TTL             0x17
 128 #define DHCP_MTU                0x1a
 129 #define DHCP_BROADCAST          0x1c
 130 #define DHCP_NTP_SERVER         0x2a
 131 #define DHCP_WINS_SERVER        0x2c
 132 #define DHCP_REQUESTED_IP       0x32
 133 #define DHCP_LEASE_TIME         0x33
 134 #define DHCP_OPTION_OVER        0x34
 135 #define DHCP_MESSAGE_TYPE       0x35
 136 #define DHCP_SERVER_ID          0x36
 137 #define DHCP_PARAM_REQ          0x37
 138 #define DHCP_MESSAGE            0x38
 139 #define DHCP_MAX_SIZE           0x39
 140 #define DHCP_T1                 0x3a
 141 #define DHCP_T2                 0x3b
 142 #define DHCP_VENDOR             0x3c
 143 #define DHCP_CLIENT_ID          0x3d
 144
 145 /* miscellaneous defines */
 146 #define MAC_BCAST_ADDR          (unsigned char *) "\xff\xff\xff\xff\xff\xff"
 147 #define OPT_CODE 0
 148 #define OPT_LEN 1
 149 #define OPT_DATA 2
 150
 151 enum {
 152         OPTION_IP = 1,
 153         OPTION_IP_PAIR,
 154         OPTION_STRING,
 155         OPTION_BOOLEAN,
 156         OPTION_U8,
 157         OPTION_U16,
 158         OPTION_S16,
 159         OPTION_U32,
 160         OPTION_S32
 161 };
 162
 163 #define OPTION_REQ      0x10    /* have the client request this option */
 164 #define OPTION_LIST     0x20    /* There can be a list of 1 or more of these */
 165
 166 #ifdef SYSLOG
 167 # define LOG(level, str, args...) do { printf(str, ## args); \
 168                                 printf("\n"); \
 169                                 syslog(level, str, ## args); } while(0)
 170 # define OPEN_LOG(name) openlog(name, 0, 0)
 171 # define CLOSE_LOG() closelog()
 172 #else
 173 # define LOG_EMERG      "EMERGENCY!"
 174 # define LOG_ALERT      "ALERT!"
 175 # define LOG_CRIT       "critical!"
 176 # define LOG_WARNING    "warning"
 177 # define LOG_ERR        "error"
 178 # define LOG_INFO       "info"
 179 # define LOG_DEBUG      "debug"
 180 # define LOG(level, str, args...) do { printf("%s, " str "\n", level, ## args); } while(0)
 181 # define OPEN_LOG(name)
 182 # define CLOSE_LOG()
 183 #endif
 184
 185 #ifdef DEBUG
 186 # undef DEBUG
 187 # define DEBUG(level, str, args...) LOG(level, str, ## args)
 188 # define DEBUGGING
 189 #else
 190 # define DEBUG(level, str, args...)
 191 #endif
 192
 193 struct dhcpMessage {
 194         u_int8_t op;
 195         u_int8_t htype;
 196         u_int8_t hlen;
 197         u_int8_t hops;
 198         u_int32_t xid;
 199         u_int16_t secs;
 200         u_int16_t flags;
 201         u_int32_t ciaddr;
 202         u_int32_t yiaddr;
 203         u_int32_t siaddr;
 204         u_int32_t giaddr;
 205         u_int8_t chaddr[16];
 206         u_int8_t sname[64];
 207         u_int8_t file[128];
 208         u_int32_t cookie;
 209         u_int8_t options[308];  /* 312 - cookie */
 210 };
 211
 212 struct client_config_t {
 213         char foreground;        /* Do not fork */
 214         char quit_after_lease;  /* Quit after obtaining lease */
 215         char abort_if_no_lease; /* Abort if no lease */
 216         char *interface;        /* The name of the interface to use */
 217         char *pidfile;          /* Optionally store the process ID */
 218         char *script;           /* User script to run at dhcp events */
 219         unsigned char *clientid;        /* Optional client id to use */
 220         unsigned char *hostname;        /* Optional hostname to use */
 221         int ifindex;            /* Index number of the interface to use */
 222         unsigned char arp[6];   /* Our arp address */
 223 };
 224
 225 struct client_config_t client_config = {
 226         /* Default options. */
 227         abort_if_no_lease:0,
 228         foreground:0,
 229         quit_after_lease:0,
 230         interface:"eth0",
 231         pidfile:NULL,
 232         script:DEFAULT_SCRIPT,
 233         clientid:NULL,
 234         hostname:NULL,
 235         ifindex:0,
 236         arp:"\0\0\0\0\0\0",     /* appease gcc-3.0 */
 237 };
 238
 239 struct dhcp_option {
 240         char name[10];
 241         char flags;
 242         unsigned char code;
 243 };
 244
 245 struct udp_dhcp_packet {
 246         struct iphdr ip;
 247         struct udphdr udp;
 248         struct dhcpMessage data;
 249 };
 250
 251 static const struct dhcp_option options[] = {
 252         /* name[10] flags                   code */
 253         {"subnet", OPTION_IP | OPTION_REQ, 0x01},
 254         {"timezone", OPTION_S32, 0x02},
 255         {"router", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03},
 256         {"timesvr", OPTION_IP | OPTION_LIST, 0x04},
 257         {"namesvr", OPTION_IP | OPTION_LIST, 0x05},
 258         {"dns", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06},
 259         {"logsvr", OPTION_IP | OPTION_LIST, 0x07},
 260         {"cookiesvr", OPTION_IP | OPTION_LIST, 0x08},
 261         {"lprsvr", OPTION_IP | OPTION_LIST, 0x09},
 262         {"hostname", OPTION_STRING | OPTION_REQ, 0x0c},
 263         {"bootsize", OPTION_U16, 0x0d},
 264         {"domain", OPTION_STRING | OPTION_REQ, 0x0f},
 265         {"swapsvr", OPTION_IP, 0x10},
 266         {"rootpath", OPTION_STRING, 0x11},
 267         {"ipttl", OPTION_U8, 0x17},
 268         {"mtu", OPTION_U16, 0x1a},
 269         {"broadcast", OPTION_IP | OPTION_REQ, 0x1c},
 270         {"ntpsrv", OPTION_IP | OPTION_LIST, 0x2a},
 271         {"wins", OPTION_IP | OPTION_LIST, 0x2c},
 272         {"requestip", OPTION_IP, 0x32},
 273         {"lease", OPTION_U32, 0x33},
 274         {"dhcptype", OPTION_U8, 0x35},
 275         {"serverid", OPTION_IP, 0x36},
 276         {"message", OPTION_STRING, 0x38},
 277         {"tftp", OPTION_STRING, 0x42},
 278         {"bootfile", OPTION_STRING, 0x43},
 279         {"", 0x00, 0x00}
 280 };
 281
 282 /* Lengths of the different option types */
 283 static const unsigned char option_lengths[] = {
 284         [OPTION_IP] = 4,
 285         [OPTION_IP_PAIR] = 8,
 286         [OPTION_BOOLEAN] = 1,
 287         [OPTION_STRING] = 1,
 288         [OPTION_U8] = 1,
 289         [OPTION_U16] = 2,
 290         [OPTION_S16] = 2,
 291         [OPTION_U32] = 4,
 292         [OPTION_S32] = 4
 293 };
 294
 295 /* get a rough idea of how long an option will be (rounding up...) */
 296 static const unsigned char max_option_length[] = {
 297         [OPTION_IP] = sizeof("255.255.255.255 "),
 298         [OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2,
 299         [OPTION_STRING] = 1,
 300         [OPTION_BOOLEAN] = sizeof("yes "),
 301         [OPTION_U8] = sizeof("255 "),
 302         [OPTION_U16] = sizeof("65535 "),
 303         [OPTION_S16] = sizeof("-32768 "),
 304         [OPTION_U32] = sizeof("4294967295 "),
 305         [OPTION_S32] = sizeof("-2147483684 "),
 306 };
 307
 308 /* return the position of the 'end' option (no bounds checking) */
 309 static int end_option(unsigned char *optionptr)
 310 {
 311         int i = 0;
 312
 313         while (optionptr[i] != DHCP_END) {
 314                 if (optionptr[i] == DHCP_PADDING)
 315                         i++;
 316                 else
 317                         i += optionptr[i + OPT_LEN] + 2;
 318         }
 319         return i;
 320 }
 321
 322 /* add an option string to the options (an option string contains an option code,
 323  * length, then data) */
 324 static int add_option_string(unsigned char *optionptr, unsigned char *string)
 325 {
 326         int end = end_option(optionptr);
 327
 328         /* end position + string length + option code/length + end option */
 329         if (end + string[OPT_LEN] + 2 + 1 >= 308) {
 330                 LOG(LOG_ERR, "Option 0x%02x did not fit into the packet!",
 331                         string[OPT_CODE]);
 332                 return 0;
 333         }
 334         DEBUG(LOG_INFO, "adding option 0x%02x", string[OPT_CODE]);
 335         memcpy(optionptr + end, string, string[OPT_LEN] + 2);
 336         optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
 337         return string[OPT_LEN] + 2;
 338 }
 339
 340 /* add a one to four byte option to a packet */
 341 static int add_simple_option(unsigned char *optionptr, unsigned char code,
 342                                                          u_int32_t data)
 343 {
 344         char length = 0;
 345         int i;
 346         unsigned char option[2 + 4];
 347         unsigned char *u8;
 348         u_int16_t *u16;
 349         u_int32_t *u32;
 350         u_int32_t aligned;
 351
 352         u8 = (unsigned char *) &aligned;
 353         u16 = (u_int16_t *) & aligned;
 354         u32 = &aligned;
 355
 356         for (i = 0; options[i].code; i++)
 357                 if (options[i].code == code) {
 358                         length = option_lengths[options[i].flags & TYPE_MASK];
 359                 }
 360
 361         if (!length) {
 362                 DEBUG(LOG_ERR, "Could not add option 0x%02x", code);
 363                 return 0;
 364         }
 365
 366         option[OPT_CODE] = code;
 367         option[OPT_LEN] = length;
 368
 369         switch (length) {
 370         case 1:
 371                 *u8 = data;
 372                 break;
 373         case 2:
 374                 *u16 = data;
 375                 break;
 376         case 4:
 377                 *u32 = data;
 378                 break;
 379         }
 380
 381         memcpy(option + 2, &aligned, length);
 382         return add_option_string(optionptr, option);
 383 }
 384
 385 static u_int16_t checksum(void *addr, int count)
 386 {
 387         /* Compute Internet Checksum for "count" bytes
 388          *         beginning at location "addr".
 389          */
 390         register int32_t sum = 0;
 391         u_int16_t *source = (u_int16_t *) addr;
 392
 393         while (count > 1) {
 394                 /*  This is the inner loop */
 395                 sum += *source++;
 396                 count -= 2;
 397         }
 398
 399         /*  Add left-over byte, if any */
 400         if (count > 0) {
 401                 sum += *(unsigned char *) source;
 402         }
 403
 404         /*  Fold 32-bit sum to 16 bits */
 405         while (sum >> 16) {
 406                 sum = (sum & 0xffff) + (sum >> 16);
 407         }
 408
 409         return ~sum;
 410 }
 411
 412 /* Constuct a ip/udp header for a packet, and specify the source and dest hardware address */
 413 static int raw_packet(struct dhcpMessage *payload, u_int32_t source_ip,
 414                                           int source_port, u_int32_t dest_ip, int dest_port,
 415                                           unsigned char *dest_arp, int ifindex)
 416 {
 417         int l_fd;
 418         int result;
 419         struct sockaddr_ll dest;
 420         struct udp_dhcp_packet packet;
 421
 422         if ((l_fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
 423                 DEBUG(LOG_ERR, "socket call failed: %s", strerror(errno));
 424                 return -1;
 425         }
 426
 427         memset(&dest, 0, sizeof(dest));
 428         memset(&packet, 0, sizeof(packet));
 429
 430         dest.sll_family = AF_PACKET;
 431         dest.sll_protocol = htons(ETH_P_IP);
 432         dest.sll_ifindex = ifindex;
 433         dest.sll_halen = 6;
 434         memcpy(dest.sll_addr, dest_arp, 6);
 435         if (bind(l_fd, (struct sockaddr *) &dest, sizeof(struct sockaddr_ll)) < 0) {
 436                 DEBUG(LOG_ERR, "bind call failed: %s", strerror(errno));
 437                 close(l_fd);
 438                 return -1;
 439         }
 440
 441         packet.ip.protocol = IPPROTO_UDP;
 442         packet.ip.saddr = source_ip;
 443         packet.ip.daddr = dest_ip;
 444         packet.udp.source = htons(source_port);
 445         packet.udp.dest = htons(dest_port);
 446         packet.udp.len = htons(sizeof(packet.udp) + sizeof(struct dhcpMessage));        /* cheat on the psuedo-header */
 447         packet.ip.tot_len = packet.udp.len;
 448         memcpy(&(packet.data), payload, sizeof(struct dhcpMessage));
 449         packet.udp.check = checksum(&packet, sizeof(struct udp_dhcp_packet));
 450
 451         packet.ip.tot_len = htons(sizeof(struct udp_dhcp_packet));
 452         packet.ip.ihl = sizeof(packet.ip) >> 2;
 453         packet.ip.version = IPVERSION;
 454         packet.ip.ttl = IPDEFTTL;
 455         packet.ip.check = checksum(&(packet.ip), sizeof(packet.ip));
 456
 457         result =
 458                 sendto(l_fd, &packet, sizeof(struct udp_dhcp_packet), 0,
 459                            (struct sockaddr *) &dest, sizeof(dest));
 460         if (result <= 0) {
 461                 DEBUG(LOG_ERR, "write on socket failed: %s", strerror(errno));
 462         }
 463         close(l_fd);
 464         return result;
 465 }
 466
 467 /* Let the kernel do all the work for packet generation */
 468 static int kernel_packet(struct dhcpMessage *payload, u_int32_t source_ip,
 469                                                  int source_port, u_int32_t dest_ip, int dest_port)
 470 {
 471         int n = 1;
 472         int l_fd, result;
 473         struct sockaddr_in client;
 474
 475         if ((l_fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
 476                 return -1;
 477         }
 478
 479         if (setsockopt(l_fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) ==
 480                 -1) {
 481                 return -1;
 482         }
 483
 484         memset(&client, 0, sizeof(client));
 485         client.sin_family = AF_INET;
 486         client.sin_port = htons(source_port);
 487         client.sin_addr.s_addr = source_ip;
 488
 489         if (bind(l_fd, (struct sockaddr *) &client, sizeof(struct sockaddr)) ==
 490                 -1) {
 491                 return -1;
 492         }
 493
 494         memset(&client, 0, sizeof(client));
 495         client.sin_family = AF_INET;
 496         client.sin_port = htons(dest_port);
 497         client.sin_addr.s_addr = dest_ip;
 498
 499         if (connect(l_fd, (struct sockaddr *) &client, sizeof(struct sockaddr)) ==
 500                 -1) {
 501                 return -1;
 502         }
 503
 504         result = write(l_fd, payload, sizeof(struct dhcpMessage));
 505         close(l_fd);
 506         return result;
 507 }
 508
 509 /* initialize a packet with the proper defaults */
 510 static void init_packet(struct dhcpMessage *packet, char type)
 511 {
 512         struct vendor {
 513                 char vendor, length;
 514                 char str[sizeof("udhcp " VERSION)];
 515         }
 516         vendor_id = {
 517         DHCP_VENDOR, sizeof("udhcp " VERSION) - 1, "udhcp " VERSION};
 518
 519         memset(packet, 0, sizeof(struct dhcpMessage));
 520         switch (type) {
 521         case DHCPDISCOVER:
 522         case DHCPREQUEST:
 523         case DHCPRELEASE:
 524         case DHCPINFORM:
 525                 packet->op = BOOTREQUEST;
 526                 break;
 527         case DHCPOFFER:
 528         case DHCPACK:
 529         case DHCPNAK:
 530                 packet->op = BOOTREPLY;
 531         }
 532         packet->htype = ETH_10MB;
 533         packet->hlen = ETH_10MB_LEN;
 534         packet->cookie = htonl(DHCP_MAGIC);
 535         packet->options[0] = DHCP_END;
 536         add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type);
 537
 538         memcpy(packet->chaddr, client_config.arp, 6);
 539         add_option_string(packet->options, client_config.clientid);
 540         if (client_config.hostname) {
 541                 add_option_string(packet->options, client_config.hostname);
 542         }
 543         add_option_string(packet->options, (unsigned char *) &vendor_id);
 544 }
 545
 546
 547 /* Add a paramater request list for stubborn DHCP servers. Pull the data
 548  * from the struct in options.c. Don't do bounds checking here because it
 549  * goes towards the head of the packet. */
 550 static void add_requests(struct dhcpMessage *packet)
 551 {
 552         int end = end_option(packet->options);
 553         int i, len = 0;
 554
 555         packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
 556         for (i = 0; options[i].code; i++) {
 557                 if (options[i].flags & OPTION_REQ) {
 558                         packet->options[end + OPT_DATA + len++] = options[i].code;
 559                 }
 560         }
 561         packet->options[end + OPT_LEN] = len;
 562         packet->options[end + OPT_DATA + len] = DHCP_END;
 563
 564 }
 565
 566 /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
 567 static inline int send_discover(unsigned long xid, unsigned long requested)
 568 {
 569         struct dhcpMessage packet;
 570
 571         init_packet(&packet, DHCPDISCOVER);
 572         packet.xid = xid;
 573         if (requested) {
 574                 add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
 575         }
 576         add_requests(&packet);
 577         DEBUG(LOG_DEBUG, "Sending discover...");
 578         return raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
 579                                           SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
 580 }
 581
 582 /* Broadcasts a DHCP request message */
 583 static inline int send_selecting(unsigned long xid, unsigned long server,
 584                                                                  unsigned long requested)
 585 {
 586         struct dhcpMessage packet;
 587         struct in_addr addr;
 588
 589         init_packet(&packet, DHCPREQUEST);
 590         packet.xid = xid;
 591
 592         add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
 593         add_simple_option(packet.options, DHCP_SERVER_ID, server);
 594
 595         add_requests(&packet);
 596         addr.s_addr = requested;
 597         DEBUG(LOG_DEBUG, "Sending select for %s...", inet_ntoa(addr));
 598         return raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
 599                                           SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
 600 }
 601
 602
 603 /* Unicasts or broadcasts a DHCP renew message */
 604 static int send_renew(unsigned long xid, unsigned long server,
 605                                           unsigned long ciaddr)
 606 {
 607         struct dhcpMessage packet;
 608
 609         init_packet(&packet, DHCPREQUEST);
 610         packet.xid = xid;
 611         packet.ciaddr = ciaddr;
 612
 613         add_requests(&packet);
 614         DEBUG(LOG_DEBUG, "Sending renew...");
 615         if (server) {
 616                 return kernel_packet(&packet, ciaddr, CLIENT_PORT, server,
 617                                                          SERVER_PORT);
 618         }
 619         return raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
 620                                           SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
 621 }
 622
 623 /* Create a random xid */
 624 static unsigned long random_xid(void)
 625 {
 626         static int initialized;
 627
 628         if (!initialized) {
 629                 srand(time(0));
 630                 initialized++;
 631         }
 632         return rand();
 633 }
 634
 635 /* just a little helper */
 636 static void change_mode(int new_mode)
 637 {
 638         DEBUG(LOG_INFO, "entering %s listen mode",
 639                   new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
 640         close(fd_main);
 641         fd_main = -1;
 642         listen_mode = new_mode;
 643 }
 644
 645
 646 /* SIGUSR1 handler (renew) */
 647 static void renew_requested(int sig)
 648 {
 649         sig = 0;
 650         LOG(LOG_INFO, "Received SIGUSR1");
 651         if (state == BOUND || state == RENEWING || state == REBINDING ||
 652                 state == RELEASED) {
 653                 change_mode(LISTEN_KERNEL);
 654                 packet_num = 0;
 655                 state = RENEW_REQUESTED;
 656         }
 657
 658         if (state == RELEASED) {
 659                 change_mode(LISTEN_RAW);
 660                 state = INIT_SELECTING;
 661         }
 662
 663         /* Kill any timeouts because the user wants this to hurry along */
 664         timeout = 0;
 665 }
 666
 667 /* get an option with bounds checking (warning, not aligned). */
 668 static unsigned char *get_option(struct dhcpMessage *packet, int code)
 669 {
 670         int i, length;
 671         unsigned char *optionptr;
 672         int over = 0, done = 0, curr = OPTION_FIELD;
 673
 674         optionptr = packet->options;
 675         i = 0;
 676         length = 308;
 677         while (!done) {
 678                 if (i >= length) {
 679                         LOG(LOG_WARNING, "bogus packet, option fields too long.");
 680                         return NULL;
 681                 }
 682                 if (optionptr[i + OPT_CODE] == code) {
 683                         if (i + 1 + optionptr[i + OPT_LEN] >= length) {
 684                                 LOG(LOG_WARNING, "bogus packet, option fields too long.");
 685                                 return NULL;
 686                         }
 687                         return optionptr + i + 2;
 688                 }
 689                 switch (optionptr[i + OPT_CODE]) {
 690                 case DHCP_PADDING:
 691                         i++;
 692                         break;
 693                 case DHCP_OPTION_OVER:
 694                         if (i + 1 + optionptr[i + OPT_LEN] >= length) {
 695                                 LOG(LOG_WARNING, "bogus packet, option fields too long.");
 696                                 return NULL;
 697                         }
 698                         over = optionptr[i + 3];
 699                         i += optionptr[OPT_LEN] + 2;
 700                         break;
 701                 case DHCP_END:
 702                         if (curr == OPTION_FIELD && over & FILE_FIELD) {
 703                                 optionptr = packet->file;
 704                                 i = 0;
 705                                 length = 128;
 706                                 curr = FILE_FIELD;
 707                         } else if (curr == FILE_FIELD && over & SNAME_FIELD) {
 708                                 optionptr = packet->sname;
 709                                 i = 0;
 710                                 length = 64;
 711                                 curr = SNAME_FIELD;
 712                         } else {
 713                                 done = 1;
 714                         }
 715                         break;
 716                 default:
 717                         i += optionptr[OPT_LEN + i] + 2;
 718                 }
 719         }
 720         return NULL;
 721 }
 722
 723 static int sprintip(char *dest, char *pre, unsigned char *ip)
 724 {
 725         return sprintf(dest, "%s%d.%d.%d.%d ", pre, ip[0], ip[1], ip[2], ip[3]);
 726 }
 727
 728
 729 /* Fill dest with the text of option 'option'. */
 730 static inline void fill_options(char *dest, unsigned char *option,
 731                                                                 const struct dhcp_option *type_p)
 732 {
 733         int type, optlen;
 734         u_int16_t val_u16;
 735         int16_t val_s16;
 736         u_int32_t val_u32;
 737         int32_t val_s32;
 738         int len = option[OPT_LEN - 2];
 739
 740         dest += sprintf(dest, "%s=", type_p->name);
 741
 742         type = type_p->flags & TYPE_MASK;
 743         optlen = option_lengths[type];
 744         for (;;) {
 745                 switch (type) {
 746                 case OPTION_IP_PAIR:
 747                         dest += sprintip(dest, "", option);
 748                         *(dest++) = '/';
 749                         option += 4;
 750                         optlen = 4;
 751                 case OPTION_IP: /* Works regardless of host byte order. */
 752                         dest += sprintip(dest, "", option);
 753                         break;
 754                 case OPTION_BOOLEAN:
 755                         dest += sprintf(dest, *option ? "yes " : "no ");
 756                         break;
 757                 case OPTION_U8:
 758                         dest += sprintf(dest, "%u ", *option);
 759                         break;
 760                 case OPTION_U16:
 761                         memcpy(&val_u16, option, 2);
 762                         dest += sprintf(dest, "%u ", ntohs(val_u16));
 763                         break;
 764                 case OPTION_S16:
 765                         memcpy(&val_s16, option, 2);
 766                         dest += sprintf(dest, "%d ", ntohs(val_s16));
 767                         break;
 768                 case OPTION_U32:
 769                         memcpy(&val_u32, option, 4);
 770                         dest += sprintf(dest, "%lu ", (unsigned long) ntohl(val_u32));
 771                         break;
 772                 case OPTION_S32:
 773                         memcpy(&val_s32, option, 4);
 774                         dest += sprintf(dest, "%ld ", (long) ntohl(val_s32));
 775                         break;
 776                 case OPTION_STRING:
 777                         memcpy(dest, option, len);
 778                         dest[len] = '\0';
 779                         return;         /* Short circuit this case */
 780                 }
 781                 option += optlen;
 782                 len -= optlen;
 783                 if (len <= 0) {
 784                         break;
 785                 }
 786         }
 787 }
 788
 789 static char *find_env(const char *prefix, char *defaultstr)
 790 {
 791         extern char **environ;
 792         char **ptr;
 793         const int len = strlen(prefix);
 794
 795         for (ptr = environ; *ptr != NULL; ptr++) {
 796                 if (strncmp(prefix, *ptr, len) == 0) {
 797                         return *ptr;
 798                 }
 799         }
 800         return defaultstr;
 801 }
 802
 803 /* put all the paramaters into an environment */
 804 static char **fill_envp(struct dhcpMessage *packet)
 805 {
 806         /* supported options are easily added here */
 807         int num_options = 0;
 808         int i, j;
 809         char **envp;
 810         unsigned char *temp;
 811         char over = 0;
 812
 813         if (packet == NULL) {
 814                 num_options = 0;
 815         } else {
 816                 for (i = 0; options[i].code; i++) {
 817                         if (get_option(packet, options[i].code)) {
 818                                 num_options++;
 819                         }
 820                 }
 821                 if (packet->siaddr) {
 822                         num_options++;
 823                 }
 824                 if ((temp = get_option(packet, DHCP_OPTION_OVER))) {
 825                         over = *temp;
 826                 }
 827                 if (!(over & FILE_FIELD) && packet->file[0]) {
 828                         num_options++;
 829                 }
 830                 if (!(over & SNAME_FIELD) && packet->sname[0]) {
 831                         num_options++;
 832                 }
 833         }
 834
 835         envp = xmalloc((num_options + 5) * sizeof(char *));
 836         envp[0] = xmalloc(sizeof("interface=") + strlen(client_config.interface));
 837         sprintf(envp[0], "interface=%s", client_config.interface);
 838         envp[1] = find_env("PATH", "PATH=/bin:/usr/bin:/sbin:/usr/sbin");
 839         envp[2] = find_env("HOME", "HOME=/");
 840
 841         if (packet == NULL) {
 842                 envp[3] = NULL;
 843                 return envp;
 844         }
 845
 846         envp[3] = xmalloc(sizeof("ip=255.255.255.255"));
 847         sprintip(envp[3], "ip=", (unsigned char *) &packet->yiaddr);
 848         for (i = 0, j = 4; options[i].code; i++) {
 849                 if ((temp = get_option(packet, options[i].code))) {
 850                         envp[j] =
 851                                 xmalloc(max_option_length[(&options[i])->flags & TYPE_MASK] *
 852                                                 (temp[OPT_LEN - 2] /
 853                                                  option_lengths[(&options[i])->flags & TYPE_MASK]) +
 854                                                 strlen((&options[i])->name) + 2);
 855                         fill_options(envp[j], temp, &options[i]);
 856                         j++;
 857                 }
 858         }
 859         if (packet->siaddr) {
 860                 envp[j] = xmalloc(sizeof("siaddr=255.255.255.255"));
 861                 sprintip(envp[j++], "siaddr=", (unsigned char *) &packet->yiaddr);
 862         }
 863         if (!(over & FILE_FIELD) && packet->file[0]) {
 864                 /* watch out for invalid packets */
 865                 packet->file[sizeof(packet->file) - 1] = '\0';
 866                 envp[j] = xmalloc(sizeof("boot_file=") + strlen(packet->file));
 867                 sprintf(envp[j++], "boot_file=%s", packet->file);
 868         }
 869         if (!(over & SNAME_FIELD) && packet->sname[0]) {
 870                 /* watch out for invalid packets */
 871                 packet->sname[sizeof(packet->sname) - 1] = '\0';
 872                 envp[j] = xmalloc(sizeof("sname=") + strlen(packet->sname));
 873                 sprintf(envp[j++], "sname=%s", packet->sname);
 874         }
 875         envp[j] = NULL;
 876         return envp;
 877 }
 878
 879 /* Call a script with a par file and env vars */
 880 static void run_script(struct dhcpMessage *packet, const char *name)
 881 {
 882         int pid;
 883         char **envp;
 884
 885         if (client_config.script == NULL) {
 886                 return;
 887         }
 888
 889         /* call script */
 890         pid = fork();
 891         if (pid) {
 892                 waitpid(pid, NULL, 0);
 893                 return;
 894         } else if (pid == 0) {
 895                 envp = fill_envp(packet);
 896
 897                 /* close fd's? */
 898
 899                 /* exec script */
 900                 DEBUG(LOG_INFO, "execle'ing %s", client_config.script);
 901                 execle(client_config.script, client_config.script, name, NULL, envp);
 902                 LOG(LOG_ERR, "script %s failed: %s",
 903                         client_config.script, strerror(errno));
 904                 exit(1);
 905         }
 906 }
 907
 908 /* SIGUSR2 handler (release) */
 909 static void release_requested(int sig)
 910 {
 911         sig = 0;
 912         LOG(LOG_INFO, "Received SIGUSR2");
 913         /* send release packet */
 914         if (state == BOUND || state == RENEWING || state == REBINDING) {
 915                 struct dhcpMessage packet;
 916
 917                 init_packet(&packet, DHCPRELEASE);
 918                 packet.xid = random_xid();
 919                 packet.ciaddr = requested_ip;
 920
 921                 add_simple_option(packet.options, DHCP_REQUESTED_IP, requested_ip);
 922                 add_simple_option(packet.options, DHCP_SERVER_ID, server_addr);
 923
 924                 DEBUG(LOG_DEBUG, "Sending release...");
 925                 kernel_packet(&packet, requested_ip, CLIENT_PORT, server_addr,
 926                                           SERVER_PORT);
 927                 run_script(NULL, "deconfig");
 928         }
 929
 930         change_mode(LISTEN_NONE);
 931         state = RELEASED;
 932         timeout = 0x7fffffff;
 933 }
 934
 935
 936 static int pidfile_acquire(char *pidfile)
 937 {
 938         int pid_fd;
 939
 940         if (pidfile == NULL) {
 941                 return -1;
 942         }
 943         pid_fd = open(pidfile, O_CREAT | O_WRONLY, 0644);
 944         if (pid_fd < 0) {
 945                 LOG(LOG_ERR, "Unable to open pidfile %s: %s\n",
 946                         pidfile, strerror(errno));
 947         } else {
 948                 lockf(pid_fd, F_LOCK, 0);
 949         }
 950
 951         return pid_fd;
 952 }
 953
 954
 955 static void pidfile_write_release(int pid_fd)
 956 {
 957         FILE *out;
 958
 959         if (pid_fd < 0) {
 960                 return;
 961         }
 962         if ((out = fdopen(pid_fd, "w")) != NULL) {
 963                 fprintf(out, "%d\n", getpid());
 964                 fclose(out);
 965         }
 966         lockf(pid_fd, F_UNLCK, 0);
 967         close(pid_fd);
 968 }
 969
 970 /* Exit and cleanup */
 971 static void exit_client(int retval)
 972 {
 973         unlink(client_config.pidfile);
 974         if (client_config.pidfile) {
 975                 unlink(client_config.pidfile);
 976         }
 977         CLOSE_LOG();
 978         exit(retval);
 979 }
 980
 981
 982 /* SIGTERM handler */
 983 static void terminate(int sig)
 984 {
 985         sig = 0;
 986         LOG(LOG_INFO, "Received SIGTERM");
 987         exit_client(0);
 988 }
 989
 990
 991 static inline int read_interface(char *interface, int *ifindex,
 992                                                                  u_int32_t * addr, unsigned char *arp)
 993 {
 994         int l_fd;
 995         struct ifreq ifr;
 996         struct sockaddr_in *s_in;
 997
 998         memset(&ifr, 0, sizeof(struct ifreq));
 999         if ((l_fd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) >= 0) {
1000                 ifr.ifr_addr.sa_family = AF_INET;
1001                 strcpy(ifr.ifr_name, interface);
1002
1003                 if (addr) {
1004                         if (ioctl(l_fd, SIOCGIFADDR, &ifr) == 0) {
1005                                 s_in = (struct sockaddr_in *) &ifr.ifr_addr;
1006                                 *addr = s_in->sin_addr.s_addr;
1007                                 DEBUG(LOG_INFO, "%s (our ip) = %s", ifr.ifr_name,
1008                                           inet_ntoa(s_in->sin_addr));
1009                         } else {
1010                                 LOG(LOG_ERR, "SIOCGIFADDR failed!: %s", strerror(errno));
1011                                 return -1;
1012                         }
1013                 }
1014
1015                 if (ioctl(l_fd, SIOCGIFINDEX, &ifr) == 0) {
1016                         DEBUG(LOG_INFO, "adapter index %d", ifr.ifr_ifindex);
1017                         *ifindex = ifr.ifr_ifindex;
1018                 } else {
1019                         LOG(LOG_ERR, "SIOCGIFINDEX failed!: %s", strerror(errno));
1020                         return -1;
1021                 }
1022                 if (ioctl(l_fd, SIOCGIFHWADDR, &ifr) == 0) {
1023                         memcpy(arp, ifr.ifr_hwaddr.sa_data, 6);
1024                         DEBUG(LOG_INFO,
1025                                   "adapter hardware address %02x:%02x:%02x:%02x:%02x:%02x",
1026                                   arp[0], arp[1], arp[2], arp[3], arp[4], arp[5]);
1027                 } else {
1028                         LOG(LOG_ERR, "SIOCGIFHWADDR failed!: %s", strerror(errno));
1029                         return -1;
1030                 }
1031         } else {
1032                 LOG(LOG_ERR, "socket failed!: %s", strerror(errno));
1033                 return -1;
1034         }
1035         close(l_fd);
1036         return 0;
1037 }
1038
1039
1040 static inline int listen_socket(unsigned int ip, int port, char *inf)
1041 {
1042         struct ifreq interface;
1043         int l_fd;
1044         struct sockaddr_in addr;
1045         int n = 1;
1046
1047         DEBUG(LOG_INFO, "Opening listen socket on 0x%08x:%d %s\n", ip, port, inf);
1048         if ((l_fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
1049                 DEBUG(LOG_ERR, "socket call failed: %s", strerror(errno));
1050                 return -1;
1051         }
1052
1053         memset(&addr, 0, sizeof(addr));
1054         addr.sin_family = AF_INET;
1055         addr.sin_port = htons(port);
1056         addr.sin_addr.s_addr = ip;
1057
1058         if (setsockopt(l_fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) ==
1059                 -1) {
1060                 close(l_fd);
1061                 return -1;
1062         }
1063         if (setsockopt(l_fd, SOL_SOCKET, SO_BROADCAST, (char *) &n, sizeof(n)) ==
1064                 -1) {
1065                 close(l_fd);
1066                 return -1;
1067         }
1068
1069         strncpy(interface.ifr_ifrn.ifrn_name, inf, IFNAMSIZ);
1070         if (setsockopt
1071                 (l_fd, SOL_SOCKET, SO_BINDTODEVICE, (char *) &interface,
1072                  sizeof(interface)) < 0) {
1073                 close(l_fd);
1074                 return -1;
1075         }
1076
1077         if (bind(l_fd, (struct sockaddr *) &addr, sizeof(struct sockaddr)) == -1) {
1078                 close(l_fd);
1079                 return -1;
1080         }
1081
1082         return l_fd;
1083 }
1084
1085
1086 static int raw_socket(int ifindex)
1087 {
1088         int l_fd;
1089         struct sockaddr_ll sock;
1090
1091         DEBUG(LOG_INFO, "Opening raw socket on ifindex %d\n", ifindex);
1092         if ((l_fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
1093                 DEBUG(LOG_ERR, "socket call failed: %s", strerror(errno));
1094                 return -1;
1095         }
1096
1097         sock.sll_family = AF_PACKET;
1098         sock.sll_protocol = htons(ETH_P_IP);
1099         sock.sll_ifindex = ifindex;
1100         if (bind(l_fd, (struct sockaddr *) &sock, sizeof(sock)) < 0) {
1101                 DEBUG(LOG_ERR, "bind call failed: %s", strerror(errno));
1102                 close(l_fd);
1103                 return -1;
1104         }
1105
1106         return l_fd;
1107
1108 }
1109
1110 /* read a packet from socket fd, return -1 on read error, -2 on packet error */
1111 static int get_packet(struct dhcpMessage *packet, int l_fd)
1112 {
1113         int bytes;
1114         int i;
1115         const char broken_vendors[][8] = {
1116                 "MSFT 98",
1117                 ""
1118         };
1119         char unsigned *vendor;
1120
1121         memset(packet, 0, sizeof(struct dhcpMessage));
1122         bytes = read(l_fd, packet, sizeof(struct dhcpMessage));
1123         if (bytes < 0) {
1124                 DEBUG(LOG_INFO, "couldn't read on listening socket, ignoring");
1125                 return -1;
1126         }
1127
1128         if (ntohl(packet->cookie) != DHCP_MAGIC) {
1129                 LOG(LOG_ERR, "received bogus message, ignoring");
1130                 return -2;
1131         }
1132         DEBUG(LOG_INFO, "Received a packet");
1133
1134         if (packet->op == BOOTREQUEST
1135                 && (vendor = get_option(packet, DHCP_VENDOR))) {
1136                 for (i = 0; broken_vendors[i][0]; i++) {
1137                         if (vendor[OPT_LEN - 2] ==
1138                                 (unsigned char) strlen(broken_vendors[i])
1139                                 && !strncmp(vendor, broken_vendors[i], vendor[OPT_LEN - 2])) {
1140                                 DEBUG(LOG_INFO, "broken client (%s), forcing broadcast",
1141                                           broken_vendors[i]);
1142                                 packet->flags |= htons(BROADCAST_FLAG);
1143                         }
1144                 }
1145         }
1146
1147         return bytes;
1148 }
1149
1150 static inline int get_raw_packet(struct dhcpMessage *payload, int l_fd)
1151 {
1152         int bytes;
1153         struct udp_dhcp_packet packet;
1154         u_int32_t source, dest;
1155         u_int16_t check;
1156
1157         memset(&packet, 0, sizeof(struct udp_dhcp_packet));
1158         bytes = read(l_fd, &packet, sizeof(struct udp_dhcp_packet));
1159         if (bytes < 0) {
1160                 DEBUG(LOG_INFO, "couldn't read on raw listening socket -- ignoring");
1161                 usleep(500000); /* possible down interface, looping condition */
1162                 return -1;
1163         }
1164
1165         if (bytes < (int) (sizeof(struct iphdr) + sizeof(struct udphdr))) {
1166                 DEBUG(LOG_INFO, "message too short, ignoring");
1167                 return -1;
1168         }
1169
1170         if (bytes < ntohs(packet.ip.tot_len)) {
1171                 DEBUG(LOG_INFO, "Truncated packet");
1172                 return -1;
1173         }
1174
1175         /* ignore any extra garbage bytes */
1176         bytes = ntohs(packet.ip.tot_len);
1177
1178         /* Make sure its the right packet for us, and that it passes sanity checks */
1179         if (packet.ip.protocol != IPPROTO_UDP || packet.ip.version != IPVERSION ||
1180                 packet.ip.ihl != sizeof(packet.ip) >> 2
1181                 || packet.udp.dest != htons(CLIENT_PORT)
1182                 || bytes > (int) sizeof(struct udp_dhcp_packet)
1183                 || ntohs(packet.udp.len) != (short) (bytes - sizeof(packet.ip))) {
1184                 DEBUG(LOG_INFO, "unrelated/bogus packet");
1185                 return -1;
1186         }
1187
1188         /* check IP checksum */
1189         check = packet.ip.check;
1190         packet.ip.check = 0;
1191         if (check != checksum(&(packet.ip), sizeof(packet.ip))) {
1192                 DEBUG(LOG_INFO, "bad IP header checksum, ignoring");
1193                 return -1;
1194         }
1195
1196         /* verify the UDP checksum by replacing the header with a psuedo header */
1197         source = packet.ip.saddr;
1198         dest = packet.ip.daddr;
1199         check = packet.udp.check;
1200         packet.udp.check = 0;
1201         memset(&packet.ip, 0, sizeof(packet.ip));
1202
1203         packet.ip.protocol = IPPROTO_UDP;
1204         packet.ip.saddr = source;
1205         packet.ip.daddr = dest;
1206         packet.ip.tot_len = packet.udp.len;     /* cheat on the psuedo-header */
1207         if (check && check != checksum(&packet, bytes)) {
1208                 DEBUG(LOG_ERR, "packet with bad UDP checksum received, ignoring");
1209                 return -1;
1210         }
1211
1212         memcpy(payload, &(packet.data),
1213                    bytes - (sizeof(packet.ip) + sizeof(packet.udp)));
1214
1215         if (ntohl(payload->cookie) != DHCP_MAGIC) {
1216                 LOG(LOG_ERR, "received bogus message (bad magic) -- ignoring");
1217                 return -1;
1218         }
1219         DEBUG(LOG_INFO, "oooooh!!! got some!");
1220         return bytes - (sizeof(packet.ip) + sizeof(packet.udp));
1221 }
1222
1223
1224 int udhcpc_main(int argc, char *argv[])
1225 {
1226         unsigned char *temp, *message;
1227         unsigned long t1 = 0, t2 = 0, xid = 0;
1228         unsigned long start = 0, lease;
1229         fd_set rfds;
1230         int retval;
1231         struct timeval tv;
1232         int c, len;
1233         struct dhcpMessage packet;
1234         struct in_addr temp_addr;
1235         int pid_fd;
1236         time_t now;
1237
1238         static struct option l_options[] = {
1239                 {"clientid", required_argument, 0, 'c'},
1240                 {"foreground", no_argument, 0, 'f'},
1241                 {"hostname", required_argument, 0, 'H'},
1242                 {"help", no_argument, 0, 'h'},
1243                 {"interface", required_argument, 0, 'i'},
1244                 {"now", no_argument, 0, 'n'},
1245                 {"pidfile", required_argument, 0, 'p'},
1246                 {"quit", no_argument, 0, 'q'},
1247                 {"request", required_argument, 0, 'r'},
1248                 {"script", required_argument, 0, 's'},
1249                 {"version", no_argument, 0, 'v'},
1250                 {0, 0, 0, 0}
1251         };
1252
1253         /* get options */
1254         while (1) {
1255                 int option_index = 0;
1256
1257                 c = getopt_long(argc, argv, "c:fH:i:np:qr:s:v", l_options,
1258                                                 &option_index);
1259                 if (c == -1) {
1260                         break;
1261                 }
1262
1263                 switch (c) {
1264                 case 'c':
1265                         len = strlen(optarg);
1266                         if (len > 255) {
1267                                 len = 255;
1268                         }
1269                         if (client_config.clientid) {
1270                                 free(client_config.clientid);
1271                         }
1272                         client_config.clientid = xmalloc(len + 2);
1273                         client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
1274                         client_config.clientid[OPT_LEN] = len;
1275                         client_config.clientid[OPT_DATA] = '\0';
1276                         strncpy(client_config.clientid + 3, optarg, len - 1);
1277                         break;
1278                 case 'f':
1279                         client_config.foreground = 1;
1280                         break;
1281                 case 'H':
1282                         len = strlen(optarg);
1283                         if (len > 255) {
1284                                 len = 255;
1285                         }
1286                         if (client_config.hostname) {
1287                                 free(client_config.hostname);
1288                         }
1289                         client_config.hostname = xmalloc(len + 2);
1290                         client_config.hostname[OPT_CODE] = DHCP_HOST_NAME;
1291                         client_config.hostname[OPT_LEN] = len;
1292                         strncpy(client_config.hostname + 2, optarg, len);
1293                         break;
1294                 case 'i':
1295                         client_config.interface = optarg;
1296                         break;
1297                 case 'n':
1298                         client_config.abort_if_no_lease = 1;
1299                         break;
1300                 case 'p':
1301                         client_config.pidfile = optarg;
1302                         break;
1303                 case 'q':
1304                         client_config.quit_after_lease = 1;
1305                         break;
1306                 case 'r':
1307                         requested_ip = inet_addr(optarg);
1308                         break;
1309                 case 's':
1310                         client_config.script = optarg;
1311                         break;
1312                 case 'v':
1313                         printf("udhcpcd, version %s\n\n", VERSION);
1314                         exit_client(0);
1315                         break;
1316                 default:
1317                         show_usage();
1318                 }
1319         }
1320
1321         OPEN_LOG("udhcpc");
1322         LOG(LOG_INFO, "udhcp client (v%s) started", VERSION);
1323
1324         pid_fd = pidfile_acquire(client_config.pidfile);
1325         pidfile_write_release(pid_fd);
1326
1327         if (read_interface
1328                 (client_config.interface, &client_config.ifindex, NULL,
1329                  client_config.arp) < 0) {
1330                 exit_client(1);
1331         }
1332
1333         if (!client_config.clientid) {
1334                 client_config.clientid = xmalloc(6 + 3);
1335                 client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
1336                 client_config.clientid[OPT_LEN] = 7;
1337                 client_config.clientid[OPT_DATA] = 1;
1338                 memcpy(client_config.clientid + 3, client_config.arp, 6);
1339         }
1340
1341         /* setup signal handlers */
1342         signal(SIGUSR1, renew_requested);
1343         signal(SIGUSR2, release_requested);
1344         signal(SIGTERM, terminate);
1345
1346         state = INIT_SELECTING;
1347         run_script(NULL, "deconfig");
1348         change_mode(LISTEN_RAW);
1349
1350         for (;;) {
1351                 tv.tv_sec = timeout - time(0);
1352                 tv.tv_usec = 0;
1353                 FD_ZERO(&rfds);
1354
1355                 if (listen_mode != LISTEN_NONE && fd_main < 0) {
1356                         if (listen_mode == LISTEN_KERNEL) {
1357                                 fd_main =
1358                                         listen_socket(INADDR_ANY, CLIENT_PORT,
1359                                                                   client_config.interface);
1360                         } else {
1361                                 fd_main = raw_socket(client_config.ifindex);
1362                         }
1363                         if (fd_main < 0) {
1364                                 LOG(LOG_ERR, "FATAL: couldn't listen on socket, %s",
1365                                         strerror(errno));
1366                                 exit_client(0);
1367                         }
1368                 }
1369                 if (fd_main >= 0) {
1370                         FD_SET(fd_main, &rfds);
1371                 }
1372
1373                 if (tv.tv_sec > 0) {
1374                         DEBUG(LOG_INFO, "Waiting on select...\n");
1375                         retval = select(fd_main + 1, &rfds, NULL, NULL, &tv);
1376                 } else {
1377                         retval = 0;     /* If we already timed out, fall through */
1378                 }
1379
1380                 now = time(0);
1381                 if (retval == 0) {
1382                         /* timeout dropped to zero */
1383                         switch (state) {
1384                         case INIT_SELECTING:
1385                                 if (packet_num < 3) {
1386                                         if (packet_num == 0) {
1387                                                 xid = random_xid();
1388                                         }
1389                                         /* send discover packet */
1390                                         send_discover(xid, requested_ip);       /* broadcast */
1391
1392                                         timeout = now + ((packet_num == 2) ? 10 : 2);
1393                                         packet_num++;
1394                                 } else {
1395                                         if (client_config.abort_if_no_lease) {
1396                                                 LOG(LOG_INFO, "No lease, failing.");
1397                                                 exit_client(1);
1398                                         }
1399                                         /* wait to try again */
1400                                         packet_num = 0;
1401                                         timeout = now + 60;
1402                                 }
1403                                 break;
1404                         case RENEW_REQUESTED:
1405                         case REQUESTING:
1406                                 if (packet_num < 3) {
1407                                         /* send request packet */
1408                                         if (state == RENEW_REQUESTED) {
1409                                                 send_renew(xid, server_addr, requested_ip);     /* unicast */
1410                                         } else {
1411                                                 send_selecting(xid, server_addr, requested_ip); /* broadcast */
1412                                         }
1413                                         timeout = now + ((packet_num == 2) ? 10 : 2);
1414                                         packet_num++;
1415                                 } else {
1416                                         /* timed out, go back to init state */
1417                                         state = INIT_SELECTING;
1418                                         timeout = now;
1419                                         packet_num = 0;
1420                                         change_mode(LISTEN_RAW);
1421                                 }
1422                                 break;
1423                         case BOUND:
1424                                 /* Lease is starting to run out, time to enter renewing state */
1425                                 state = RENEWING;
1426                                 change_mode(LISTEN_KERNEL);
1427                                 DEBUG(LOG_INFO, "Entering renew state");
1428                                 /* fall right through */
1429                         case RENEWING:
1430                                 /* Either set a new T1, or enter REBINDING state */
1431                                 if ((t2 - t1) <= (lease / 14400 + 1)) {
1432                                         /* timed out, enter rebinding state */
1433                                         state = REBINDING;
1434                                         timeout = now + (t2 - t1);
1435                                         DEBUG(LOG_INFO, "Entering rebinding state");
1436                                 } else {
1437                                         /* send a request packet */
1438                                         send_renew(xid, server_addr, requested_ip);     /* unicast */
1439
1440                                         t1 = (t2 - t1) / 2 + t1;
1441                                         timeout = t1 + start;
1442                                 }
1443                                 break;
1444                         case REBINDING:
1445                                 /* Either set a new T2, or enter INIT state */
1446                                 if ((lease - t2) <= (lease / 14400 + 1)) {
1447                                         /* timed out, enter init state */
1448                                         state = INIT_SELECTING;
1449                                         LOG(LOG_INFO, "Lease lost, entering init state");
1450                                         run_script(NULL, "deconfig");
1451                                         timeout = now;
1452                                         packet_num = 0;
1453                                         change_mode(LISTEN_RAW);
1454                                 } else {
1455                                         /* send a request packet */
1456                                         send_renew(xid, 0, requested_ip);       /* broadcast */
1457
1458                                         t2 = (lease - t2) / 2 + t2;
1459                                         timeout = t2 + start;
1460                                 }
1461                                 break;
1462                         case RELEASED:
1463                                 /* yah, I know, *you* say it would never happen */
1464                                 timeout = 0x7fffffff;
1465                                 break;
1466                         }
1467                 } else if (retval > 0 && listen_mode != LISTEN_NONE
1468                                    && FD_ISSET(fd_main, &rfds)) {
1469                         /* a packet is ready, read it */
1470
1471                         if (listen_mode == LISTEN_KERNEL) {
1472                                 len = get_packet(&packet, fd_main);
1473                         } else {
1474                                 len = get_raw_packet(&packet, fd_main);
1475                         }
1476                         if (len == -1 && errno != EINTR) {
1477                                 DEBUG(LOG_INFO, "error on read, %s, reopening socket",
1478                                           strerror(errno));
1479                                 change_mode(listen_mode);       /* just close and reopen */
1480                         }
1481                         if (len < 0) {
1482                                 continue;
1483                         }
1484
1485                         if (packet.xid != xid) {
1486                                 DEBUG(LOG_INFO, "Ignoring XID %lx (our xid is %lx)",
1487                                           (unsigned long) packet.xid, xid);
1488                                 continue;
1489                         }
1490
1491                         if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
1492                                 DEBUG(LOG_ERR, "couldnt get option from packet -- ignoring");
1493                                 continue;
1494                         }
1495
1496                         switch (state) {
1497                         case INIT_SELECTING:
1498                                 /* Must be a DHCPOFFER to one of our xid's */
1499                                 if (*message == DHCPOFFER) {
1500                                         if ((temp = get_option(&packet, DHCP_SERVER_ID))) {
1501                                                 memcpy(&server_addr, temp, 4);
1502                                                 xid = packet.xid;
1503                                                 requested_ip = packet.yiaddr;
1504
1505                                                 /* enter requesting state */
1506                                                 state = REQUESTING;
1507                                                 timeout = now;
1508                                                 packet_num = 0;
1509                                         } else {
1510                                                 DEBUG(LOG_ERR, "No server ID in message");
1511                                         }
1512                                 }
1513                                 break;
1514                         case RENEW_REQUESTED:
1515                         case REQUESTING:
1516                         case RENEWING:
1517                         case REBINDING:
1518                                 if (*message == DHCPACK) {
1519                                         if (!(temp = get_option(&packet, DHCP_LEASE_TIME))) {
1520                                                 LOG(LOG_ERR,
1521                                                         "No lease time with ACK, using 1 hour lease");
1522                                                 lease = 60 * 60;
1523                                         } else {
1524                                                 memcpy(&lease, temp, 4);
1525                                                 lease = ntohl(lease);
1526                                         }
1527
1528                                         /* enter bound state */
1529                                         t1 = lease / 2;
1530
1531                                         /* little fixed point for n * .875 */
1532                                         t2 = (lease * 0x7) >> 3;
1533                                         temp_addr.s_addr = packet.yiaddr;
1534                                         LOG(LOG_INFO, "Lease of %s obtained, lease time %ld",
1535                                                 inet_ntoa(temp_addr), lease);
1536                                         start = now;
1537                                         timeout = t1 + start;
1538                                         requested_ip = packet.yiaddr;
1539                                         run_script(&packet,
1540                                                            ((state == RENEWING
1541                                                                  || state == REBINDING) ? "renew" : "bound"));
1542
1543                                         state = BOUND;
1544                                         change_mode(LISTEN_NONE);
1545                                         {
1546                                                 int pid_fd2;
1547
1548                                                 if (client_config.quit_after_lease) {
1549                                                         exit_client(0);
1550                                                 } else if (!client_config.foreground) {
1551                                                         pid_fd2 = pidfile_acquire(client_config.pidfile);       /* hold lock during fork. */
1552                                                         if (daemon(0, 0) == -1) {
1553                                                                 perror("fork");
1554                                                                 exit_client(1);
1555                                                         }
1556                                                         client_config.foreground = 1;   /* Do not fork again. */
1557                                                         pidfile_write_release(pid_fd2);
1558                                                 }
1559                                         }
1560                                 } else if (*message == DHCPNAK) {
1561                                         /* return to init state */
1562                                         LOG(LOG_INFO, "Received DHCP NAK");
1563                                         run_script(&packet, "nak");
1564                                         if (state != REQUESTING) {
1565                                                 run_script(NULL, "deconfig");
1566                                         }
1567                                         state = INIT_SELECTING;
1568                                         timeout = now;
1569                                         requested_ip = 0;
1570                                         packet_num = 0;
1571                                         change_mode(LISTEN_RAW);
1572                                         sleep(3);       /* avoid excessive network traffic */
1573                                 }
1574                                 break;
1575                                 /* case BOUND, RELEASED: - ignore all packets */
1576                         }
1577                 } else if (retval == -1 && errno == EINTR) {
1578                         /* a signal was caught */
1579
1580                 } else {
1581                         /* An error occured */
1582                         DEBUG(LOG_ERR, "Error on select");
1583                 }
1584
1585         }
1586         return 0;
1587 }