networking/udhcp/files.c

   1 /*
   2  * files.c -- DHCP server file manipulation *
   3  * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
   4  */
   5
   6 #include <sys/socket.h>
   7 #include <arpa/inet.h>
   8 #include <string.h>
   9 #include <stdlib.h>
  10 #include <time.h>
  11 #include <ctype.h>
  12 #include <netdb.h>
  13
  14 #include <netinet/ether.h>
  15 #include "static_leases.h"
  16
  17 #include "dhcpd.h"
  18 #include "options.h"
  19 #include "files.h"
  20 #include "common.h"
  21
  22 /*
  23  * Domain names may have 254 chars, and string options can be 254
  24  * chars long. However, 80 bytes will be enough for most, and won't
  25  * hog up memory. If you have a special application, change it
  26  */
  27 #define READ_CONFIG_BUF_SIZE 80
  28
  29 /* on these functions, make sure you datatype matches */
  30 static int read_ip(const char *line, void *arg)
  31 {
  32         struct in_addr *addr = arg;
  33         struct hostent *host;
  34         int retval = 1;
  35
  36         if (!inet_aton(line, addr)) {
  37                 if ((host = gethostbyname(line)))
  38                         addr->s_addr = *((unsigned long *) host->h_addr_list[0]);
  39                 else retval = 0;
  40         }
  41         return retval;
  42 }
  43
  44 static int read_mac(const char *line, void *arg)
  45 {
  46         uint8_t *mac_bytes = arg;
  47         struct ether_addr *temp_ether_addr;
  48         int retval = 1;
  49
  50         temp_ether_addr = ether_aton(line);
  51
  52         if(temp_ether_addr == NULL)
  53                 retval = 0;
  54         else
  55                 memcpy(mac_bytes, temp_ether_addr, 6);
  56
  57         return retval;
  58 }
  59
  60
  61 static int read_str(const char *line, void *arg)
  62 {
  63         char **dest = arg;
  64
  65         free(*dest);
  66         *dest = strdup(line);
  67
  68         return 1;
  69 }
  70
  71
  72 static int read_u32(const char *line, void *arg)
  73 {
  74         uint32_t *dest = arg;
  75         char *endptr;
  76         *dest = strtoul(line, &endptr, 0);
  77         return endptr[0] == '\0';
  78 }
  79
  80
  81 static int read_yn(const char *line, void *arg)
  82 {
  83         char *dest = arg;
  84         int retval = 1;
  85
  86         if (!strcasecmp("yes", line))
  87                 *dest = 1;
  88         else if (!strcasecmp("no", line))
  89                 *dest = 0;
  90         else retval = 0;
  91
  92         return retval;
  93 }
  94
  95
  96 /* find option 'code' in opt_list */
  97 struct option_set *find_option(struct option_set *opt_list, char code)
  98 {
  99         while (opt_list && opt_list->data[OPT_CODE] < code)
 100                 opt_list = opt_list->next;
 101
 102         if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list;
 103         else return NULL;
 104 }
 105
 106
 107 /* add an option to the opt_list */
 108 static void attach_option(struct option_set **opt_list, struct dhcp_option *option, char *buffer, int length)
 109 {
 110         struct option_set *existing, *new, **curr;
 111
 112         /* add it to an existing option */
 113         if ((existing = find_option(*opt_list, option->code))) {
 114                 DEBUG(LOG_INFO, "Attaching option %s to existing member of list", option->name);
 115                 if (option->flags & OPTION_LIST) {
 116                         if (existing->data[OPT_LEN] + length <= 255) {
 117                                 existing->data = realloc(existing->data,
 118                                                 existing->data[OPT_LEN] + length + 2);
 119                                 memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
 120                                 existing->data[OPT_LEN] += length;
 121                         } /* else, ignore the data, we could put this in a second option in the future */
 122                 } /* else, ignore the new data */
 123         } else {
 124                 DEBUG(LOG_INFO, "Attaching option %s to list", option->name);
 125
 126                 /* make a new option */
 127                 new = xmalloc(sizeof(struct option_set));
 128                 new->data = xmalloc(length + 2);
 129                 new->data[OPT_CODE] = option->code;
 130                 new->data[OPT_LEN] = length;
 131                 memcpy(new->data + 2, buffer, length);
 132
 133                 curr = opt_list;
 134                 while (*curr && (*curr)->data[OPT_CODE] < option->code)
 135                         curr = &(*curr)->next;
 136
 137                 new->next = *curr;
 138                 *curr = new;
 139         }
 140 }
 141
 142
 143 /* read a dhcp option and add it to opt_list */
 144 static int read_opt(const char *const_line, void *arg)
 145 {
 146         struct option_set **opt_list = arg;
 147         char *opt, *val, *endptr;
 148         struct dhcp_option *option;
 149         int retval = 0, length;
 150         char buffer[8];
 151         char *line;
 152         uint16_t *result_u16 = (uint16_t *) buffer;
 153         uint32_t *result_u32 = (uint32_t *) buffer;
 154
 155         /* Cheat, the only const line we'll actually get is "" */
 156         line = (char *) const_line;
 157         if (!(opt = strtok(line, " \t="))) return 0;
 158
 159         for (option = dhcp_options; option->code; option++)
 160                 if (!strcasecmp(option->name, opt))
 161                         break;
 162
 163         if (!option->code) return 0;
 164
 165         do {
 166                 if (!(val = strtok(NULL, ", \t"))) break;
 167                 length = option_lengths[option->flags & TYPE_MASK];
 168                 retval = 0;
 169                 opt = buffer; /* new meaning for variable opt */
 170                 switch (option->flags & TYPE_MASK) {
 171                 case OPTION_IP:
 172                         retval = read_ip(val, buffer);
 173                         break;
 174                 case OPTION_IP_PAIR:
 175                         retval = read_ip(val, buffer);
 176                         if (!(val = strtok(NULL, ", \t/-"))) retval = 0;
 177                         if (retval) retval = read_ip(val, buffer + 4);
 178                         break;
 179                 case OPTION_STRING:
 180                         length = strlen(val);
 181                         if (length > 0) {
 182                                 if (length > 254) length = 254;
 183                                 opt = val;
 184                                 retval = 1;
 185                         }
 186                         break;
 187                 case OPTION_BOOLEAN:
 188                         retval = read_yn(val, buffer);
 189                         break;
 190                 case OPTION_U8:
 191                         buffer[0] = strtoul(val, &endptr, 0);
 192                         retval = (endptr[0] == '\0');
 193                         break;
 194                 case OPTION_U16:
 195                         *result_u16 = htons(strtoul(val, &endptr, 0));
 196                         retval = (endptr[0] == '\0');
 197                         break;
 198                 case OPTION_S16:
 199                         *result_u16 = htons(strtol(val, &endptr, 0));
 200                         retval = (endptr[0] == '\0');
 201                         break;
 202                 case OPTION_U32:
 203                         *result_u32 = htonl(strtoul(val, &endptr, 0));
 204                         retval = (endptr[0] == '\0');
 205                         break;
 206                 case OPTION_S32:
 207                         *result_u32 = htonl(strtol(val, &endptr, 0));
 208                         retval = (endptr[0] == '\0');
 209                         break;
 210                 default:
 211                         break;
 212                 }
 213                 if (retval)
 214                         attach_option(opt_list, option, opt, length);
 215         } while (retval && option->flags & OPTION_LIST);
 216         return retval;
 217 }
 218
 219 static int read_staticlease(const char *const_line, void *arg)
 220 {
 221
 222         char *line;
 223         char *mac_string;
 224         char *ip_string;
 225         uint8_t *mac_bytes;
 226         uint32_t *ip;
 227
 228
 229         /* Allocate memory for addresses */
 230         mac_bytes = xmalloc(sizeof(unsigned char) * 8);
 231         ip = xmalloc(sizeof(uint32_t));
 232
 233         /* Read mac */
 234         line = (char *) const_line;
 235         mac_string = strtok(line, " \t");
 236         read_mac(mac_string, mac_bytes);
 237
 238         /* Read ip */
 239         ip_string = strtok(NULL, " \t");
 240         read_ip(ip_string, ip);
 241
 242         addStaticLease(arg, mac_bytes, ip);
 243
 244         if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg);
 245
 246         return 1;
 247
 248 }
 249
 250
 251 static const struct config_keyword keywords[] = {
 252         /* keyword      handler   variable address              default */
 253         {"start",       read_ip,  &(server_config.start),       "192.168.0.20"},
 254         {"end",         read_ip,  &(server_config.end),         "192.168.0.254"},
 255         {"interface",   read_str, &(server_config.interface),   "eth0"},
 256         {"option",      read_opt, &(server_config.options),     ""},
 257         {"opt",         read_opt, &(server_config.options),     ""},
 258         {"max_leases",  read_u32, &(server_config.max_leases),  "254"},
 259         {"remaining",   read_yn,  &(server_config.remaining),   "yes"},
 260         {"auto_time",   read_u32, &(server_config.auto_time),   "7200"},
 261         {"decline_time",read_u32, &(server_config.decline_time),"3600"},
 262         {"conflict_time",read_u32,&(server_config.conflict_time),"3600"},
 263         {"offer_time",  read_u32, &(server_config.offer_time),  "60"},
 264         {"min_lease",   read_u32, &(server_config.min_lease),   "60"},
 265         {"lease_file",  read_str, &(server_config.lease_file),  LEASES_FILE},
 266         {"pidfile",     read_str, &(server_config.pidfile),     "/var/run/udhcpd.pid"},
 267         {"notify_file", read_str, &(server_config.notify_file), ""},
 268         {"siaddr",      read_ip,  &(server_config.siaddr),      "0.0.0.0"},
 269         {"sname",       read_str, &(server_config.sname),       ""},
 270         {"boot_file",   read_str, &(server_config.boot_file),   ""},
 271         {"static_lease",read_staticlease, &(server_config.static_leases),       ""},
 272         /*ADDME: static lease */
 273         {"",            NULL,     NULL,                         ""}
 274 };
 275
 276
 277 int read_config(const char *file)
 278 {
 279         FILE *in;
 280         char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
 281         int i, lm = 0;
 282
 283         for (i = 0; keywords[i].keyword[0]; i++)
 284                 if (keywords[i].def[0])
 285                         keywords[i].handler(keywords[i].def, keywords[i].var);
 286
 287         if (!(in = fopen(file, "r"))) {
 288                 LOG(LOG_ERR, "unable to open config file: %s", file);
 289                 return 0;
 290         }
 291
 292         while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
 293                 char debug_orig[READ_CONFIG_BUF_SIZE];
 294
 295                 lm++;
 296                 if (strchr(buffer, '\n')) *(strchr(buffer, '\n')) = '\0';
 297                 if (ENABLE_FEATURE_UDHCP_DEBUG) strcpy(debug_orig, buffer);
 298                 if (strchr(buffer, '#')) *(strchr(buffer, '#')) = '\0';
 299
 300                 if (!(token = strtok(buffer, " \t"))) continue;
 301                 if (!(line = strtok(NULL, ""))) continue;
 302
 303                 /* eat leading whitespace */
 304                 line = line + strspn(line, " \t=");
 305                 /* eat trailing whitespace */
 306                 for (i = strlen(line); i > 0 && isspace(line[i - 1]); i--);
 307                 line[i] = '\0';
 308
 309                 for (i = 0; keywords[i].keyword[0]; i++)
 310                         if (!strcasecmp(token, keywords[i].keyword))
 311                                 if (!keywords[i].handler(line, keywords[i].var)) {
 312                                         LOG(LOG_ERR, "Failure parsing line %d of %s", lm, file);
 313                                         DEBUG(LOG_ERR, "unable to parse '%s'", debug_orig);
 314                                         /* reset back to the default value */
 315                                         keywords[i].handler(keywords[i].def, keywords[i].var);
 316                                 }
 317         }
 318         fclose(in);
 319         return 1;
 320 }
 321
 322
 323 void write_leases(void)
 324 {
 325         FILE *fp;
 326         unsigned int i;
 327         char buf[255];
 328         time_t curr = time(0);
 329         unsigned long tmp_time;
 330
 331         if (!(fp = fopen(server_config.lease_file, "w"))) {
 332                 LOG(LOG_ERR, "Unable to open %s for writing", server_config.lease_file);
 333                 return;
 334         }
 335
 336         for (i = 0; i < server_config.max_leases; i++) {
 337                 if (leases[i].yiaddr != 0) {
 338
 339                         /* screw with the time in the struct, for easier writing */
 340                         tmp_time = leases[i].expires;
 341
 342                         if (server_config.remaining) {
 343                                 if (lease_expired(&(leases[i])))
 344                                         leases[i].expires = 0;
 345                                 else leases[i].expires -= curr;
 346                         } /* else stick with the time we got */
 347                         leases[i].expires = htonl(leases[i].expires);
 348                         fwrite(&leases[i], sizeof(struct dhcpOfferedAddr), 1, fp);
 349
 350                         /* Then restore it when done. */
 351                         leases[i].expires = tmp_time;
 352                 }
 353         }
 354         fclose(fp);
 355
 356         if (server_config.notify_file) {
 357                 sprintf(buf, "%s %s", server_config.notify_file, server_config.lease_file);
 358                 system(buf);
 359         }
 360 }
 361
 362
 363 void read_leases(const char *file)
 364 {
 365         FILE *fp;
 366         unsigned int i = 0;
 367         struct dhcpOfferedAddr lease;
 368
 369         if (!(fp = fopen(file, "r"))) {
 370                 LOG(LOG_ERR, "Unable to open %s for reading", file);
 371                 return;
 372         }
 373
 374         while (i < server_config.max_leases && (fread(&lease, sizeof lease, 1, fp) == 1)) {
 375                 /* ADDME: is it a static lease */
 376                 if (lease.yiaddr >= server_config.start && lease.yiaddr <= server_config.end) {
 377                         lease.expires = ntohl(lease.expires);
 378                         if (!server_config.remaining) lease.expires -= time(0);
 379                         if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
 380                                 LOG(LOG_WARNING, "Too many leases while loading %s\n", file);
 381                                 break;
 382                         }
 383                         i++;
 384                 }
 385         }
 386         DEBUG(LOG_INFO, "Read %d leases", i);
 387         fclose(fp);
 388 }