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 <sys/socket.h>
   8 #include <arpa/inet.h>
   9 #include <string.h>
  10 #include <stdlib.h>
  11 #include <time.h>
  12 #include <ctype.h>
  13 #include <netdb.h>
  14
  15 #include <netinet/ether.h>
  16 #include "static_leases.h"
  17
  18 #include "dhcpd.h"
  19 #include "options.h"
  20 #include "files.h"
  21 #include "common.h"
  22
  23 /*
  24  * Domain names may have 254 chars, and string options can be 254
  25  * chars long. However, 80 bytes will be enough for most, and won't
  26  * hog up memory. If you have a special application, change it
  27  */
  28 #define READ_CONFIG_BUF_SIZE 80
  29
  30 /* on these functions, make sure you datatype matches */
  31 static int read_ip(const char *line, void *arg)
  32 {
  33         struct in_addr *addr = arg;
  34         struct hostent *host;
  35         int retval = 1;
  36
  37         if (!inet_aton(line, addr)) {
  38                 if ((host = gethostbyname(line)))
  39                         addr->s_addr = *((unsigned long *) host->h_addr_list[0]);
  40                 else retval = 0;
  41         }
  42         return retval;
  43 }
  44
  45 static int read_mac(const char *line, void *arg)
  46 {
  47         uint8_t *mac_bytes = arg;
  48         struct ether_addr *temp_ether_addr;
  49         int retval = 1;
  50
  51         temp_ether_addr = ether_aton(line);
  52
  53         if(temp_ether_addr == NULL)
  54                 retval = 0;
  55         else
  56                 memcpy(mac_bytes, temp_ether_addr, 6);
  57
  58         return retval;
  59 }
  60
  61
  62 static int read_str(const char *line, void *arg)
  63 {
  64         char **dest = arg;
  65
  66         free(*dest);
  67         *dest = strdup(line);
  68
  69         return 1;
  70 }
  71
  72
  73 static int read_u32(const char *line, void *arg)
  74 {
  75         uint32_t *dest = arg;
  76         char *endptr;
  77         *dest = strtoul(line, &endptr, 0);
  78         return endptr[0] == '\0';
  79 }
  80
  81
  82 static int read_yn(const char *line, void *arg)
  83 {
  84         char *dest = arg;
  85         int retval = 1;
  86
  87         if (!strcasecmp("yes", line))
  88                 *dest = 1;
  89         else if (!strcasecmp("no", line))
  90                 *dest = 0;
  91         else retval = 0;
  92
  93         return retval;
  94 }
  95
  96
  97 /* find option 'code' in opt_list */
  98 struct option_set *find_option(struct option_set *opt_list, char code)
  99 {
 100         while (opt_list && opt_list->data[OPT_CODE] < code)
 101                 opt_list = opt_list->next;
 102
 103         if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list;
 104         else return NULL;
 105 }
 106
 107
 108 /* add an option to the opt_list */
 109 static void attach_option(struct option_set **opt_list, struct dhcp_option *option, char *buffer, int length)
 110 {
 111         struct option_set *existing, *new, **curr;
 112
 113         /* add it to an existing option */
 114         if ((existing = find_option(*opt_list, option->code))) {
 115                 DEBUG(LOG_INFO, "Attaching option %s to existing member of list", option->name);
 116                 if (option->flags & OPTION_LIST) {
 117                         if (existing->data[OPT_LEN] + length <= 255) {
 118                                 existing->data = realloc(existing->data,
 119                                                 existing->data[OPT_LEN] + length + 2);
 120                                 memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
 121                                 existing->data[OPT_LEN] += length;
 122                         } /* else, ignore the data, we could put this in a second option in the future */
 123                 } /* else, ignore the new data */
 124         } else {
 125                 DEBUG(LOG_INFO, "Attaching option %s to list", option->name);
 126
 127                 /* make a new option */
 128                 new = xmalloc(sizeof(struct option_set));
 129                 new->data = xmalloc(length + 2);
 130                 new->data[OPT_CODE] = option->code;
 131                 new->data[OPT_LEN] = length;
 132                 memcpy(new->data + 2, buffer, length);
 133
 134                 curr = opt_list;
 135                 while (*curr && (*curr)->data[OPT_CODE] < option->code)
 136                         curr = &(*curr)->next;
 137
 138                 new->next = *curr;
 139                 *curr = new;
 140         }
 141 }
 142
 143
 144 /* read a dhcp option and add it to opt_list */
 145 static int read_opt(const char *const_line, void *arg)
 146 {
 147         struct option_set **opt_list = arg;
 148         char *opt, *val, *endptr;
 149         struct dhcp_option *option;
 150         int retval = 0, length;
 151         char buffer[8];
 152         char *line;
 153         uint16_t *result_u16 = (uint16_t *) buffer;
 154         uint32_t *result_u32 = (uint32_t *) buffer;
 155
 156         /* Cheat, the only const line we'll actually get is "" */
 157         line = (char *) const_line;
 158         if (!(opt = strtok(line, " \t="))) return 0;
 159
 160         for (option = dhcp_options; option->code; option++)
 161                 if (!strcasecmp(option->name, opt))
 162                         break;
 163
 164         if (!option->code) return 0;
 165
 166         do {
 167                 if (!(val = strtok(NULL, ", \t"))) break;
 168                 length = option_lengths[option->flags & TYPE_MASK];
 169                 retval = 0;
 170                 opt = buffer; /* new meaning for variable opt */
 171                 switch (option->flags & TYPE_MASK) {
 172                 case OPTION_IP:
 173                         retval = read_ip(val, buffer);
 174                         break;
 175                 case OPTION_IP_PAIR:
 176                         retval = read_ip(val, buffer);
 177                         if (!(val = strtok(NULL, ", \t/-"))) retval = 0;
 178                         if (retval) retval = read_ip(val, buffer + 4);
 179                         break;
 180                 case OPTION_STRING:
 181                         length = strlen(val);
 182                         if (length > 0) {
 183                                 if (length > 254) length = 254;
 184                                 opt = val;
 185                                 retval = 1;
 186                         }
 187                         break;
 188                 case OPTION_BOOLEAN:
 189                         retval = read_yn(val, buffer);
 190                         break;
 191                 case OPTION_U8:
 192                         buffer[0] = strtoul(val, &endptr, 0);
 193                         retval = (endptr[0] == '\0');
 194                         break;
 195                 case OPTION_U16:
 196                         *result_u16 = htons(strtoul(val, &endptr, 0));
 197                         retval = (endptr[0] == '\0');
 198                         break;
 199                 case OPTION_S16:
 200                         *result_u16 = htons(strtol(val, &endptr, 0));
 201                         retval = (endptr[0] == '\0');
 202                         break;
 203                 case OPTION_U32:
 204                         *result_u32 = htonl(strtoul(val, &endptr, 0));
 205                         retval = (endptr[0] == '\0');
 206                         break;
 207                 case OPTION_S32:
 208                         *result_u32 = htonl(strtol(val, &endptr, 0));
 209                         retval = (endptr[0] == '\0');
 210                         break;
 211                 default:
 212                         break;
 213                 }
 214                 if (retval)
 215                         attach_option(opt_list, option, opt, length);
 216         } while (retval && option->flags & OPTION_LIST);
 217         return retval;
 218 }
 219
 220 static int read_staticlease(const char *const_line, void *arg)
 221 {
 222
 223         char *line;
 224         char *mac_string;
 225         char *ip_string;
 226         uint8_t *mac_bytes;
 227         uint32_t *ip;
 228
 229
 230         /* Allocate memory for addresses */
 231         mac_bytes = xmalloc(sizeof(unsigned char) * 8);
 232         ip = xmalloc(sizeof(uint32_t));
 233
 234         /* Read mac */
 235         line = (char *) const_line;
 236         mac_string = strtok(line, " \t");
 237         read_mac(mac_string, mac_bytes);
 238
 239         /* Read ip */
 240         ip_string = strtok(NULL, " \t");
 241         read_ip(ip_string, ip);
 242
 243         addStaticLease(arg, mac_bytes, ip);
 244
 245         if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg);
 246
 247         return 1;
 248
 249 }
 250
 251
 252 static const struct config_keyword keywords[] = {
 253         /* keyword      handler   variable address              default */
 254         {"start",       read_ip,  &(server_config.start),       "192.168.0.20"},
 255         {"end",         read_ip,  &(server_config.end),         "192.168.0.254"},
 256         {"interface",   read_str, &(server_config.interface),   "eth0"},
 257         {"option",      read_opt, &(server_config.options),     ""},
 258         {"opt",         read_opt, &(server_config.options),     ""},
 259         {"max_leases",  read_u32, &(server_config.max_leases),  "254"},
 260         {"remaining",   read_yn,  &(server_config.remaining),   "yes"},
 261         {"auto_time",   read_u32, &(server_config.auto_time),   "7200"},
 262         {"decline_time",read_u32, &(server_config.decline_time),"3600"},
 263         {"conflict_time",read_u32,&(server_config.conflict_time),"3600"},
 264         {"offer_time",  read_u32, &(server_config.offer_time),  "60"},
 265         {"min_lease",   read_u32, &(server_config.min_lease),   "60"},
 266         {"lease_file",  read_str, &(server_config.lease_file),  LEASES_FILE},
 267         {"pidfile",     read_str, &(server_config.pidfile),     "/var/run/udhcpd.pid"},
 268         {"notify_file", read_str, &(server_config.notify_file), ""},
 269         {"siaddr",      read_ip,  &(server_config.siaddr),      "0.0.0.0"},
 270         {"sname",       read_str, &(server_config.sname),       ""},
 271         {"boot_file",   read_str, &(server_config.boot_file),   ""},
 272         {"static_lease",read_staticlease, &(server_config.static_leases),       ""},
 273         /*ADDME: static lease */
 274         {"",            NULL,     NULL,                         ""}
 275 };
 276
 277
 278 int read_config(const char *file)
 279 {
 280         FILE *in;
 281         char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
 282         int i, lm = 0;
 283
 284         for (i = 0; keywords[i].keyword[0]; i++)
 285                 if (keywords[i].def[0])
 286                         keywords[i].handler(keywords[i].def, keywords[i].var);
 287
 288         if (!(in = fopen(file, "r"))) {
 289                 LOG(LOG_ERR, "unable to open config file: %s", file);
 290                 return 0;
 291         }
 292
 293         while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
 294                 char debug_orig[READ_CONFIG_BUF_SIZE];
 295
 296                 lm++;
 297                 if (strchr(buffer, '\n')) *(strchr(buffer, '\n')) = '\0';
 298                 if (ENABLE_FEATURE_UDHCP_DEBUG) strcpy(debug_orig, buffer);
 299                 if (strchr(buffer, '#')) *(strchr(buffer, '#')) = '\0';
 300
 301                 if (!(token = strtok(buffer, " \t"))) continue;
 302                 if (!(line = strtok(NULL, ""))) continue;
 303
 304                 /* eat leading whitespace */
 305                 line = line + strspn(line, " \t=");
 306                 /* eat trailing whitespace */
 307                 for (i = strlen(line); i > 0 && isspace(line[i - 1]); 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                                         LOG(LOG_ERR, "Failure parsing line %d of %s", lm, file);
 314                                         DEBUG(LOG_ERR, "unable to parse '%s'", debug_orig);
 315                                         /* reset back to the default value */
 316                                         keywords[i].handler(keywords[i].def, keywords[i].var);
 317                                 }
 318         }
 319         fclose(in);
 320         return 1;
 321 }
 322
 323
 324 void write_leases(void)
 325 {
 326         FILE *fp;
 327         unsigned int i;
 328         char buf[255];
 329         time_t curr = time(0);
 330         unsigned long tmp_time;
 331
 332         if (!(fp = fopen(server_config.lease_file, "w"))) {
 333                 LOG(LOG_ERR, "Unable to open %s for writing", server_config.lease_file);
 334                 return;
 335         }
 336
 337         for (i = 0; i < server_config.max_leases; i++) {
 338                 if (leases[i].yiaddr != 0) {
 339
 340                         /* screw with the time in the struct, for easier writing */
 341                         tmp_time = leases[i].expires;
 342
 343                         if (server_config.remaining) {
 344                                 if (lease_expired(&(leases[i])))
 345                                         leases[i].expires = 0;
 346                                 else leases[i].expires -= curr;
 347                         } /* else stick with the time we got */
 348                         leases[i].expires = htonl(leases[i].expires);
 349                         fwrite(&leases[i], sizeof(struct dhcpOfferedAddr), 1, fp);
 350
 351                         /* Then restore it when done. */
 352                         leases[i].expires = tmp_time;
 353                 }
 354         }
 355         fclose(fp);
 356
 357         if (server_config.notify_file) {
 358                 sprintf(buf, "%s %s", server_config.notify_file, server_config.lease_file);
 359                 system(buf);
 360         }
 361 }
 362
 363
 364 void read_leases(const char *file)
 365 {
 366         FILE *fp;
 367         unsigned int i = 0;
 368         struct dhcpOfferedAddr lease;
 369
 370         if (!(fp = fopen(file, "r"))) {
 371                 LOG(LOG_ERR, "Unable to open %s for reading", file);
 372                 return;
 373         }
 374
 375         while (i < server_config.max_leases && (fread(&lease, sizeof lease, 1, fp) == 1)) {
 376                 /* ADDME: is it a static lease */
 377                 if (lease.yiaddr >= server_config.start && lease.yiaddr <= server_config.end) {
 378                         lease.expires = ntohl(lease.expires);
 379                         if (!server_config.remaining) lease.expires -= time(0);
 380                         if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
 381                                 LOG(LOG_WARNING, "Too many leases while loading %s\n", file);
 382                                 break;
 383                         }
 384                         i++;
 385                 }
 386         }
 387         DEBUG(LOG_INFO, "Read %d leases", i);
 388         fclose(fp);
 389 }