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