networking/udhcp/files.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * files.c -- DHCP server file manipulation *
   4  * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
   5  */
   6
   7 #include <netinet/ether.h>
   8
   9 #include "common.h"
  10 #include "dhcpd.h"
  11 #include "options.h"
  12
  13
  14 /* on these functions, make sure your datatype matches */
  15 static int read_ip(const char *line, void *arg)
  16 {
  17         len_and_sockaddr *lsa;
  18
  19         lsa = host_and_af2sockaddr(line, 0, AF_INET);
  20         if (lsa) {
  21                 *(uint32_t*)arg = lsa->sin.sin_addr.s_addr;
  22                 free(lsa);
  23                 return 1;
  24         }
  25         return 0;
  26 }
  27
  28 static int read_mac(const char *line, void *arg)
  29 {
  30         uint8_t *mac_bytes = arg;
  31         struct ether_addr *temp_ether_addr;
  32
  33         temp_ether_addr = ether_aton(line);
  34         if (temp_ether_addr == NULL)
  35                 return 0;
  36         memcpy(mac_bytes, temp_ether_addr, 6);
  37         return 1;
  38 }
  39
  40
  41 static int read_str(const char *line, void *arg)
  42 {
  43         char **dest = arg;
  44
  45         free(*dest);
  46         *dest = xstrdup(line);
  47         return 1;
  48 }
  49
  50
  51 static int read_u32(const char *line, void *arg)
  52 {
  53         *(uint32_t*)arg = bb_strtou32(line, NULL, 10);
  54         return errno == 0;
  55 }
  56
  57
  58 static int read_yn(const char *line, void *arg)
  59 {
  60         char *dest = arg;
  61
  62         if (!strcasecmp("yes", line)) {
  63                 *dest = 1;
  64                 return 1;
  65         }
  66         if (!strcasecmp("no", line)) {
  67                 *dest = 0;
  68                 return 1;
  69         }
  70         return 0;
  71 }
  72
  73
  74 /* find option 'code' in opt_list */
  75 struct option_set *find_option(struct option_set *opt_list, char code)
  76 {
  77         while (opt_list && opt_list->data[OPT_CODE] < code)
  78                 opt_list = opt_list->next;
  79
  80         if (opt_list && opt_list->data[OPT_CODE] == code)
  81                 return opt_list;
  82         return NULL;
  83 }
  84
  85
  86 /* add an option to the opt_list */
  87 static void attach_option(struct option_set **opt_list,
  88                 const struct dhcp_option *option, char *buffer, int length)
  89 {
  90         struct option_set *existing, *new, **curr;
  91
  92         existing = find_option(*opt_list, option->code);
  93         if (!existing) {
  94                 DEBUG("Attaching option %s to list", option->name);
  95
  96 #if ENABLE_FEATURE_RFC3397
  97                 if ((option->flags & TYPE_MASK) == OPTION_STR1035)
  98                         /* reuse buffer and length for RFC1035-formatted string */
  99                         buffer = dname_enc(NULL, 0, buffer, &length);
 100 #endif
 101
 102                 /* make a new option */
 103                 new = xmalloc(sizeof(*new));
 104                 new->data = xmalloc(length + 2);
 105                 new->data[OPT_CODE] = option->code;
 106                 new->data[OPT_LEN] = length;
 107                 memcpy(new->data + 2, buffer, length);
 108
 109                 curr = opt_list;
 110                 while (*curr && (*curr)->data[OPT_CODE] < option->code)
 111                         curr = &(*curr)->next;
 112
 113                 new->next = *curr;
 114                 *curr = new;
 115 #if ENABLE_FEATURE_RFC3397
 116                 if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
 117                         free(buffer);
 118 #endif
 119                 return;
 120         }
 121
 122         /* add it to an existing option */
 123         DEBUG("Attaching option %s to existing member of list", option->name);
 124         if (option->flags & OPTION_LIST) {
 125 #if ENABLE_FEATURE_RFC3397
 126                 if ((option->flags & TYPE_MASK) == OPTION_STR1035)
 127                         /* reuse buffer and length for RFC1035-formatted string */
 128                         buffer = dname_enc(existing->data + 2,
 129                                         existing->data[OPT_LEN], buffer, &length);
 130 #endif
 131                 if (existing->data[OPT_LEN] + length <= 255) {
 132                         existing->data = xrealloc(existing->data,
 133                                         existing->data[OPT_LEN] + length + 3);
 134                         if ((option->flags & TYPE_MASK) == OPTION_STRING) {
 135                                 /* ' ' can bring us to 256 - bad */
 136                                 if (existing->data[OPT_LEN] + length >= 255)
 137                                         return;
 138                                 /* add space separator between STRING options in a list */
 139                                 existing->data[existing->data[OPT_LEN] + 2] = ' ';
 140                                 existing->data[OPT_LEN]++;
 141                         }
 142                         memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
 143                         existing->data[OPT_LEN] += length;
 144                 } /* else, ignore the data, we could put this in a second option in the future */
 145 #if ENABLE_FEATURE_RFC3397
 146                 if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
 147                         free(buffer);
 148 #endif
 149         } /* else, ignore the new data */
 150 }
 151
 152
 153 /* read a dhcp option and add it to opt_list */
 154 static int read_opt(const char *const_line, void *arg)
 155 {
 156         struct option_set **opt_list = arg;
 157         char *opt, *val, *endptr;
 158         const struct dhcp_option *option;
 159         int retval = 0, length;
 160         char buffer[8];
 161         char *line;
 162         uint16_t *result_u16 = (uint16_t *) buffer;
 163         uint32_t *result_u32 = (uint32_t *) buffer;
 164
 165         /* Cheat, the only const line we'll actually get is "" */
 166         line = (char *) const_line;
 167         opt = strtok(line, " \t=");
 168         if (!opt) return 0;
 169
 170         option = dhcp_options;
 171         while (1) {
 172                 if (!option->code)
 173                         return 0;
 174                 if (!strcasecmp(option->name, opt))
 175                         break;
 176                 option++;
 177         }
 178
 179         do {
 180                 val = strtok(NULL, ", \t");
 181                 if (!val) break;
 182                 length = option_lengths[option->flags & TYPE_MASK];
 183                 retval = 0;
 184                 opt = buffer; /* new meaning for variable opt */
 185                 switch (option->flags & TYPE_MASK) {
 186                 case OPTION_IP:
 187                         retval = read_ip(val, buffer);
 188                         break;
 189                 case OPTION_IP_PAIR:
 190                         retval = read_ip(val, buffer);
 191                         val = strtok(NULL, ", \t/-");
 192                         if (!val)
 193                                 retval = 0;
 194                         if (retval)
 195                                 retval = read_ip(val, buffer + 4);
 196                         break;
 197                 case OPTION_STRING:
 198 #if ENABLE_FEATURE_RFC3397
 199                 case OPTION_STR1035:
 200 #endif
 201                         length = strlen(val);
 202                         if (length > 0) {
 203                                 if (length > 254) length = 254;
 204                                 opt = val;
 205                                 retval = 1;
 206                         }
 207                         break;
 208                 case OPTION_BOOLEAN:
 209                         retval = read_yn(val, buffer);
 210                         break;
 211                 case OPTION_U8:
 212                         buffer[0] = strtoul(val, &endptr, 0);
 213                         retval = (endptr[0] == '\0');
 214                         break;
 215                 /* htonX are macros in older libc's, using temp var
 216                  * in code below for safety */
 217                 /* TODO: use bb_strtoX? */
 218                 case OPTION_U16: {
 219                         unsigned long tmp = strtoul(val, &endptr, 0);
 220                         *result_u16 = htons(tmp);
 221                         retval = (endptr[0] == '\0' /*&& tmp < 0x10000*/);
 222                         break;
 223                 }
 224                 case OPTION_S16: {
 225                         long tmp = strtol(val, &endptr, 0);
 226                         *result_u16 = htons(tmp);
 227                         retval = (endptr[0] == '\0');
 228                         break;
 229                 }
 230                 case OPTION_U32: {
 231                         unsigned long tmp = strtoul(val, &endptr, 0);
 232                         *result_u32 = htonl(tmp);
 233                         retval = (endptr[0] == '\0');
 234                         break;
 235                 }
 236                 case OPTION_S32: {
 237                         long tmp = strtol(val, &endptr, 0);
 238                         *result_u32 = htonl(tmp);
 239                         retval = (endptr[0] == '\0');
 240                         break;
 241                 }
 242                 default:
 243                         break;
 244                 }
 245                 if (retval)
 246                         attach_option(opt_list, option, opt, length);
 247         } while (retval && option->flags & OPTION_LIST);
 248         return retval;
 249 }
 250
 251 static int read_staticlease(const char *const_line, void *arg)
 252 {
 253         char *line;
 254         char *mac_string;
 255         char *ip_string;
 256         uint8_t *mac_bytes;
 257         uint32_t *ip;
 258
 259         /* Allocate memory for addresses */
 260         mac_bytes = xmalloc(sizeof(unsigned char) * 8);
 261         ip = xmalloc(sizeof(uint32_t));
 262
 263         /* Read mac */
 264         line = (char *) const_line;
 265         mac_string = strtok(line, " \t");
 266         read_mac(mac_string, mac_bytes);
 267
 268         /* Read ip */
 269         ip_string = strtok(NULL, " \t");
 270         read_ip(ip_string, ip);
 271
 272         addStaticLease(arg, mac_bytes, ip);
 273
 274         if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg);
 275
 276         return 1;
 277 }
 278
 279
 280 struct config_keyword {
 281         const char *keyword;
 282         int (*handler)(const char *line, void *var);
 283         void *var;
 284         const char *def;
 285 };
 286
 287 static const struct config_keyword keywords[] = {
 288         /* keyword       handler   variable address               default */
 289         {"start",        read_ip,  &(server_config.start_ip),     "192.168.0.20"},
 290         {"end",          read_ip,  &(server_config.end_ip),       "192.168.0.254"},
 291         {"interface",    read_str, &(server_config.interface),    "eth0"},
 292         {"option",       read_opt, &(server_config.options),      ""},
 293         {"opt",          read_opt, &(server_config.options),      ""},
 294         /* Avoid "max_leases value not sane" warning by setting default
 295          * to default_end_ip - default_start_ip + 1: */
 296         {"max_leases",   read_u32, &(server_config.max_leases),   "235"},
 297         {"remaining",    read_yn,  &(server_config.remaining),    "yes"},
 298         {"auto_time",    read_u32, &(server_config.auto_time),    "7200"},
 299         {"decline_time", read_u32, &(server_config.decline_time), "3600"},
 300         {"conflict_time",read_u32, &(server_config.conflict_time),"3600"},
 301         {"offer_time",   read_u32, &(server_config.offer_time),   "60"},
 302         {"min_lease",    read_u32, &(server_config.min_lease),    "60"},
 303         {"lease_file",   read_str, &(server_config.lease_file),   LEASES_FILE},
 304         {"pidfile",      read_str, &(server_config.pidfile),      "/var/run/udhcpd.pid"},
 305         {"notify_file",  read_str, &(server_config.notify_file),  ""},
 306         {"siaddr",       read_ip,  &(server_config.siaddr),       "0.0.0.0"},
 307         {"sname",        read_str, &(server_config.sname),        ""},
 308         {"boot_file",    read_str, &(server_config.boot_file),    ""},
 309         {"static_lease", read_staticlease, &(server_config.static_leases), ""},
 310         /* ADDME: static lease */
 311 };
 312
 313
 314 /*
 315  * Domain names may have 254 chars, and string options can be 254
 316  * chars long. However, 80 bytes will be enough for most, and won't
 317  * hog up memory. If you have a special application, change it
 318  */
 319 #define READ_CONFIG_BUF_SIZE 80
 320
 321 int read_config(const char *file)
 322 {
 323         FILE *in;
 324         char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
 325         int i, lm = 0;
 326
 327         for (i = 0; i < ARRAY_SIZE(keywords); i++)
 328                 if (keywords[i].def[0])
 329                         keywords[i].handler(keywords[i].def, keywords[i].var);
 330
 331         in = fopen_or_warn(file, "r");
 332         if (!in) {
 333                 return 0;
 334         }
 335
 336         while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
 337                 char debug_orig[READ_CONFIG_BUF_SIZE];
 338                 char *p;
 339
 340                 lm++;
 341                 p = strchr(buffer, '\n');
 342                 if (p) *p = '\0';
 343                 if (ENABLE_FEATURE_UDHCP_DEBUG) strcpy(debug_orig, buffer);
 344                 p = strchr(buffer, '#');
 345                 if (p) *p = '\0';
 346
 347                 if (!(token = strtok(buffer, " \t"))) continue;
 348                 if (!(line = strtok(NULL, ""))) continue;
 349
 350                 /* eat leading whitespace */
 351                 line = skip_whitespace(line);
 352                 /* eat trailing whitespace */
 353                 i = strlen(line) - 1;
 354                 while (i >= 0 && isspace(line[i]))
 355                         line[i--] = '\0';
 356
 357                 for (i = 0; i < ARRAY_SIZE(keywords); i++)
 358                         if (!strcasecmp(token, keywords[i].keyword))
 359                                 if (!keywords[i].handler(line, keywords[i].var)) {
 360                                         bb_error_msg("cannot parse line %d of %s", lm, file);
 361                                         if (ENABLE_FEATURE_UDHCP_DEBUG)
 362                                                 bb_error_msg("cannot parse '%s'", debug_orig);
 363                                         /* reset back to the default value */
 364                                         keywords[i].handler(keywords[i].def, keywords[i].var);
 365                                 }
 366         }
 367         fclose(in);
 368
 369         server_config.start_ip = ntohl(server_config.start_ip);
 370         server_config.end_ip = ntohl(server_config.end_ip);
 371
 372         return 1;
 373 }
 374
 375
 376 void write_leases(void)
 377 {
 378         int fp;
 379         unsigned i;
 380         time_t curr = time(0);
 381         unsigned long tmp_time;
 382
 383         fp = open3_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC, 0666);
 384         if (fp < 0) {
 385                 return;
 386         }
 387
 388         for (i = 0; i < server_config.max_leases; i++) {
 389                 if (leases[i].yiaddr != 0) {
 390
 391                         /* screw with the time in the struct, for easier writing */
 392                         tmp_time = leases[i].expires;
 393
 394                         if (server_config.remaining) {
 395                                 if (lease_expired(&(leases[i])))
 396                                         leases[i].expires = 0;
 397                                 else leases[i].expires -= curr;
 398                         } /* else stick with the time we got */
 399                         leases[i].expires = htonl(leases[i].expires);
 400                         // FIXME: error check??
 401                         full_write(fp, &leases[i], sizeof(leases[i]));
 402
 403                         /* then restore it when done */
 404                         leases[i].expires = tmp_time;
 405                 }
 406         }
 407         close(fp);
 408
 409         if (server_config.notify_file) {
 410                 char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file);
 411                 system(cmd);
 412                 free(cmd);
 413         }
 414 }
 415
 416
 417 void read_leases(const char *file)
 418 {
 419         int fp;
 420         unsigned int i = 0;
 421         struct dhcpOfferedAddr lease;
 422
 423         fp = open_or_warn(file, O_RDONLY);
 424         if (fp < 0) {
 425                 return;
 426         }
 427
 428         while (i < server_config.max_leases
 429          && full_read(fp, &lease, sizeof(lease)) == sizeof(lease)
 430         ) {
 431                 /* ADDME: is it a static lease */
 432                 uint32_t y = ntohl(lease.yiaddr);
 433                 if (y >= server_config.start_ip && y <= server_config.end_ip) {
 434                         lease.expires = ntohl(lease.expires);
 435                         if (!server_config.remaining)
 436                                 lease.expires -= time(0);
 437                         if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
 438                                 bb_error_msg("too many leases while loading %s", file);
 439                                 break;
 440                         }
 441                         i++;
 442                 }
 443         }
 444         DEBUG("Read %d leases", i);
 445         close(fp);
 446 }