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 = strdup(line);
  60
  61         return 1;
  62 }
  63
  64
  65 static int read_u32(const char *line, void *arg)
  66 {
  67         return safe_strtou32(line, (uint32_t*)arg) == 0;
  68 }
  69
  70
  71 static int read_yn(const char *line, void *arg)
  72 {
  73         char *dest = arg;
  74         int retval = 1;
  75
  76         if (!strcasecmp("yes", line))
  77                 *dest = 1;
  78         else if (!strcasecmp("no", line))
  79                 *dest = 0;
  80         else retval = 0;
  81
  82         return retval;
  83 }
  84
  85
  86 /* find option 'code' in opt_list */
  87 struct option_set *find_option(struct option_set *opt_list, char code)
  88 {
  89         while (opt_list && opt_list->data[OPT_CODE] < code)
  90                 opt_list = opt_list->next;
  91
  92         if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list;
  93         else return NULL;
  94 }
  95
  96
  97 /* add an option to the opt_list */
  98 static void attach_option(struct option_set **opt_list, struct dhcp_option *option, char *buffer, int length)
  99 {
 100         struct option_set *existing, *new, **curr;
 101
 102         /* add it to an existing option */
 103         if ((existing = find_option(*opt_list, option->code))) {
 104                 DEBUG("Attaching option %s to existing member of list", option->name);
 105                 if (option->flags & OPTION_LIST) {
 106                         if (existing->data[OPT_LEN] + length <= 255) {
 107                                 existing->data = realloc(existing->data,
 108                                                 existing->data[OPT_LEN] + length + 2);
 109                                 memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
 110                                 existing->data[OPT_LEN] += length;
 111                         } /* else, ignore the data, we could put this in a second option in the future */
 112                 } /* else, ignore the new data */
 113         } else {
 114                 DEBUG("Attaching option %s to list", option->name);
 115
 116                 /* make a new option */
 117                 new = xmalloc(sizeof(struct option_set));
 118                 new->data = xmalloc(length + 2);
 119                 new->data[OPT_CODE] = option->code;
 120                 new->data[OPT_LEN] = length;
 121                 memcpy(new->data + 2, buffer, length);
 122
 123                 curr = opt_list;
 124                 while (*curr && (*curr)->data[OPT_CODE] < option->code)
 125                         curr = &(*curr)->next;
 126
 127                 new->next = *curr;
 128                 *curr = new;
 129         }
 130 }
 131
 132
 133 /* read a dhcp option and add it to opt_list */
 134 static int read_opt(const char *const_line, void *arg)
 135 {
 136         struct option_set **opt_list = arg;
 137         char *opt, *val, *endptr;
 138         struct dhcp_option *option;
 139         int retval = 0, length;
 140         char buffer[8];
 141         char *line;
 142         uint16_t *result_u16 = (uint16_t *) buffer;
 143         uint32_t *result_u32 = (uint32_t *) buffer;
 144
 145         /* Cheat, the only const line we'll actually get is "" */
 146         line = (char *) const_line;
 147         if (!(opt = strtok(line, " \t="))) return 0;
 148
 149         for (option = dhcp_options; option->code; option++)
 150                 if (!strcasecmp(option->name, opt))
 151                         break;
 152
 153         if (!option->code) return 0;
 154
 155         do {
 156                 if (!(val = strtok(NULL, ", \t"))) break;
 157                 length = option_lengths[option->flags & TYPE_MASK];
 158                 retval = 0;
 159                 opt = buffer; /* new meaning for variable opt */
 160                 switch (option->flags & TYPE_MASK) {
 161                 case OPTION_IP:
 162                         retval = read_ip(val, buffer);
 163                         break;
 164                 case OPTION_IP_PAIR:
 165                         retval = read_ip(val, buffer);
 166                         if (!(val = strtok(NULL, ", \t/-"))) retval = 0;
 167                         if (retval) retval = read_ip(val, buffer + 4);
 168                         break;
 169                 case OPTION_STRING:
 170                         length = strlen(val);
 171                         if (length > 0) {
 172                                 if (length > 254) length = 254;
 173                                 opt = val;
 174                                 retval = 1;
 175                         }
 176                         break;
 177                 case OPTION_BOOLEAN:
 178                         retval = read_yn(val, buffer);
 179                         break;
 180                 case OPTION_U8:
 181                         buffer[0] = strtoul(val, &endptr, 0);
 182                         retval = (endptr[0] == '\0');
 183                         break;
 184                 case OPTION_U16:
 185                         *result_u16 = htons(strtoul(val, &endptr, 0));
 186                         retval = (endptr[0] == '\0');
 187                         break;
 188                 case OPTION_S16:
 189                         *result_u16 = htons(strtol(val, &endptr, 0));
 190                         retval = (endptr[0] == '\0');
 191                         break;
 192                 case OPTION_U32:
 193                         *result_u32 = htonl(strtoul(val, &endptr, 0));
 194                         retval = (endptr[0] == '\0');
 195                         break;
 196                 case OPTION_S32:
 197                         *result_u32 = htonl(strtol(val, &endptr, 0));
 198                         retval = (endptr[0] == '\0');
 199                         break;
 200                 default:
 201                         break;
 202                 }
 203                 if (retval)
 204                         attach_option(opt_list, option, opt, length);
 205         } while (retval && option->flags & OPTION_LIST);
 206         return retval;
 207 }
 208
 209 static int read_staticlease(const char *const_line, void *arg)
 210 {
 211         char *line;
 212         char *mac_string;
 213         char *ip_string;
 214         uint8_t *mac_bytes;
 215         uint32_t *ip;
 216
 217
 218         /* Allocate memory for addresses */
 219         mac_bytes = xmalloc(sizeof(unsigned char) * 8);
 220         ip = xmalloc(sizeof(uint32_t));
 221
 222         /* Read mac */
 223         line = (char *) const_line;
 224         mac_string = strtok(line, " \t");
 225         read_mac(mac_string, mac_bytes);
 226
 227         /* Read ip */
 228         ip_string = strtok(NULL, " \t");
 229         read_ip(ip_string, ip);
 230
 231         addStaticLease(arg, mac_bytes, ip);
 232
 233         if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg);
 234
 235         return 1;
 236 }
 237
 238
 239 static const struct config_keyword keywords[] = {
 240         /* keyword      handler   variable address              default */
 241         {"start",       read_ip,  &(server_config.start),       "192.168.0.20"},
 242         {"end",         read_ip,  &(server_config.end),         "192.168.0.254"},
 243         {"interface",   read_str, &(server_config.interface),   "eth0"},
 244         {"option",      read_opt, &(server_config.options),     ""},
 245         {"opt",         read_opt, &(server_config.options),     ""},
 246         {"max_leases",  read_u32, &(server_config.max_leases),  "254"},
 247         {"remaining",   read_yn,  &(server_config.remaining),   "yes"},
 248         {"auto_time",   read_u32, &(server_config.auto_time),   "7200"},
 249         {"decline_time",read_u32, &(server_config.decline_time),"3600"},
 250         {"conflict_time",read_u32,&(server_config.conflict_time),"3600"},
 251         {"offer_time",  read_u32, &(server_config.offer_time),  "60"},
 252         {"min_lease",   read_u32, &(server_config.min_lease),   "60"},
 253         {"lease_file",  read_str, &(server_config.lease_file),  LEASES_FILE},
 254         {"pidfile",     read_str, &(server_config.pidfile),     "/var/run/udhcpd.pid"},
 255         {"notify_file", read_str, &(server_config.notify_file), ""},
 256         {"siaddr",      read_ip,  &(server_config.siaddr),      "0.0.0.0"},
 257         {"sname",       read_str, &(server_config.sname),       ""},
 258         {"boot_file",   read_str, &(server_config.boot_file),   ""},
 259         {"static_lease",read_staticlease, &(server_config.static_leases),       ""},
 260         /*ADDME: static lease */
 261         {"",            NULL,     NULL,                         ""}
 262 };
 263
 264
 265 int read_config(const char *file)
 266 {
 267         FILE *in;
 268         char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
 269         int i, lm = 0;
 270
 271         for (i = 0; keywords[i].keyword[0]; i++)
 272                 if (keywords[i].def[0])
 273                         keywords[i].handler(keywords[i].def, keywords[i].var);
 274
 275         in = fopen(file, "r");
 276         if (!in) {
 277                 bb_error_msg("cannot open config file: %s", file);
 278                 return 0;
 279         }
 280
 281         while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
 282                 char debug_orig[READ_CONFIG_BUF_SIZE];
 283                 char *p;
 284
 285                 lm++;
 286                 p = strchr(buffer, '\n');
 287                 if (p) *p = '\0';
 288                 if (ENABLE_FEATURE_UDHCP_DEBUG) strcpy(debug_orig, buffer);
 289                 p = strchr(buffer, '#');
 290                 if (p) *p = '\0';
 291
 292                 if (!(token = strtok(buffer, " \t"))) continue;
 293                 if (!(line = strtok(NULL, ""))) continue;
 294
 295                 /* eat leading whitespace */
 296                 line = skip_whitespace(line);
 297                 /* eat trailing whitespace */
 298                 i = strlen(line) - 1;
 299                 while (i >= 0 && isspace(line[i]))
 300                         line[i--] = '\0';
 301
 302                 for (i = 0; keywords[i].keyword[0]; i++)
 303                         if (!strcasecmp(token, keywords[i].keyword))
 304                                 if (!keywords[i].handler(line, keywords[i].var)) {
 305                                         bb_error_msg("cannot parse line %d of %s", lm, file);
 306                                         if (ENABLE_FEATURE_UDHCP_DEBUG)
 307                                                 bb_error_msg("cannot parse '%s'", debug_orig);
 308                                         /* reset back to the default value */
 309                                         keywords[i].handler(keywords[i].def, keywords[i].var);
 310                                 }
 311         }
 312         fclose(in);
 313         return 1;
 314 }
 315
 316
 317 void write_leases(void)
 318 {
 319         int fp;
 320         unsigned i;
 321         time_t curr = time(0);
 322         unsigned long tmp_time;
 323
 324         fp = open(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC, 0666);
 325         if (fp < 0) {
 326                 bb_error_msg("cannot open %s for writing", server_config.lease_file);
 327                 return;
 328         }
 329
 330         for (i = 0; i < server_config.max_leases; i++) {
 331                 if (leases[i].yiaddr != 0) {
 332
 333                         /* screw with the time in the struct, for easier writing */
 334                         tmp_time = leases[i].expires;
 335
 336                         if (server_config.remaining) {
 337                                 if (lease_expired(&(leases[i])))
 338                                         leases[i].expires = 0;
 339                                 else leases[i].expires -= curr;
 340                         } /* else stick with the time we got */
 341                         leases[i].expires = htonl(leases[i].expires);
 342                         // FIXME: error check??
 343                         full_write(fp, &leases[i], sizeof(leases[i]));
 344
 345                         /* then restore it when done */
 346                         leases[i].expires = tmp_time;
 347                 }
 348         }
 349         close(fp);
 350
 351         if (server_config.notify_file) {
 352                 char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file);
 353                 system(cmd);
 354                 free(cmd);
 355         }
 356 }
 357
 358
 359 void read_leases(const char *file)
 360 {
 361         int fp;
 362         unsigned int i = 0;
 363         struct dhcpOfferedAddr lease;
 364
 365         fp = open(file, O_RDONLY);
 366         if (fp < 0) {
 367                 bb_error_msg("cannot open %s for reading", file);
 368                 return;
 369         }
 370
 371         while (i < server_config.max_leases
 372          && full_read(fp, &lease, sizeof(lease)) == sizeof(lease)
 373         ) {
 374                 /* ADDME: is it a static lease */
 375                 if (lease.yiaddr >= server_config.start && lease.yiaddr <= server_config.end) {
 376                         lease.expires = ntohl(lease.expires);
 377                         if (!server_config.remaining) lease.expires -= time(0);
 378                         if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
 379                                 bb_error_msg("too many leases while loading %s", file);
 380                                 break;
 381                         }
 382                         i++;
 383                 }
 384         }
 385         DEBUG("Read %d leases", i);
 386         close(fp);
 387 }