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                 host = gethostbyname(line);
  39                 if (host)
  40                         addr->s_addr = *((unsigned long *) host->h_addr_list[0]);
  41                 else retval = 0;
  42         }
  43         return retval;
  44 }
  45
  46 static int read_mac(const char *line, void *arg)
  47 {
  48         uint8_t *mac_bytes = arg;
  49         struct ether_addr *temp_ether_addr;
  50         int retval = 1;
  51
  52         temp_ether_addr = ether_aton(line);
  53
  54         if(temp_ether_addr == NULL)
  55                 retval = 0;
  56         else
  57                 memcpy(mac_bytes, temp_ether_addr, 6);
  58
  59         return retval;
  60 }
  61
  62
  63 static int read_str(const char *line, void *arg)
  64 {
  65         char **dest = arg;
  66
  67         free(*dest);
  68         *dest = strdup(line);
  69
  70         return 1;
  71 }
  72
  73
  74 static int read_u32(const char *line, void *arg)
  75 {
  76         return safe_strtou32(line, (uint32_t*)arg) == 0;
  77 }
  78
  79
  80 static int read_yn(const char *line, void *arg)
  81 {
  82         char *dest = arg;
  83         int retval = 1;
  84
  85         if (!strcasecmp("yes", line))
  86                 *dest = 1;
  87         else if (!strcasecmp("no", line))
  88                 *dest = 0;
  89         else retval = 0;
  90
  91         return retval;
  92 }
  93
  94
  95 /* find option 'code' in opt_list */
  96 struct option_set *find_option(struct option_set *opt_list, char code)
  97 {
  98         while (opt_list && opt_list->data[OPT_CODE] < code)
  99                 opt_list = opt_list->next;
 100
 101         if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list;
 102         else return NULL;
 103 }
 104
 105
 106 /* add an option to the opt_list */
 107 static void attach_option(struct option_set **opt_list, struct dhcp_option *option, char *buffer, int length)
 108 {
 109         struct option_set *existing, *new, **curr;
 110
 111         /* add it to an existing option */
 112         if ((existing = find_option(*opt_list, option->code))) {
 113                 DEBUG("Attaching option %s to existing member of list", option->name);
 114                 if (option->flags & OPTION_LIST) {
 115                         if (existing->data[OPT_LEN] + length <= 255) {
 116                                 existing->data = realloc(existing->data,
 117                                                 existing->data[OPT_LEN] + length + 2);
 118                                 memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
 119                                 existing->data[OPT_LEN] += length;
 120                         } /* else, ignore the data, we could put this in a second option in the future */
 121                 } /* else, ignore the new data */
 122         } else {
 123                 DEBUG("Attaching option %s to list", option->name);
 124
 125                 /* make a new option */
 126                 new = xmalloc(sizeof(struct option_set));
 127                 new->data = xmalloc(length + 2);
 128                 new->data[OPT_CODE] = option->code;
 129                 new->data[OPT_LEN] = length;
 130                 memcpy(new->data + 2, buffer, length);
 131
 132                 curr = opt_list;
 133                 while (*curr && (*curr)->data[OPT_CODE] < option->code)
 134                         curr = &(*curr)->next;
 135
 136                 new->next = *curr;
 137                 *curr = new;
 138         }
 139 }
 140
 141
 142 /* read a dhcp option and add it to opt_list */
 143 static int read_opt(const char *const_line, void *arg)
 144 {
 145         struct option_set **opt_list = arg;
 146         char *opt, *val, *endptr;
 147         struct dhcp_option *option;
 148         int retval = 0, length;
 149         char buffer[8];
 150         char *line;
 151         uint16_t *result_u16 = (uint16_t *) buffer;
 152         uint32_t *result_u32 = (uint32_t *) buffer;
 153
 154         /* Cheat, the only const line we'll actually get is "" */
 155         line = (char *) const_line;
 156         if (!(opt = strtok(line, " \t="))) return 0;
 157
 158         for (option = dhcp_options; option->code; option++)
 159                 if (!strcasecmp(option->name, opt))
 160                         break;
 161
 162         if (!option->code) return 0;
 163
 164         do {
 165                 if (!(val = strtok(NULL, ", \t"))) break;
 166                 length = option_lengths[option->flags & TYPE_MASK];
 167                 retval = 0;
 168                 opt = buffer; /* new meaning for variable opt */
 169                 switch (option->flags & TYPE_MASK) {
 170                 case OPTION_IP:
 171                         retval = read_ip(val, buffer);
 172                         break;
 173                 case OPTION_IP_PAIR:
 174                         retval = read_ip(val, buffer);
 175                         if (!(val = strtok(NULL, ", \t/-"))) retval = 0;
 176                         if (retval) retval = read_ip(val, buffer + 4);
 177                         break;
 178                 case OPTION_STRING:
 179                         length = strlen(val);
 180                         if (length > 0) {
 181                                 if (length > 254) length = 254;
 182                                 opt = val;
 183                                 retval = 1;
 184                         }
 185                         break;
 186                 case OPTION_BOOLEAN:
 187                         retval = read_yn(val, buffer);
 188                         break;
 189                 case OPTION_U8:
 190                         buffer[0] = strtoul(val, &endptr, 0);
 191                         retval = (endptr[0] == '\0');
 192                         break;
 193                 case OPTION_U16:
 194                         *result_u16 = htons(strtoul(val, &endptr, 0));
 195                         retval = (endptr[0] == '\0');
 196                         break;
 197                 case OPTION_S16:
 198                         *result_u16 = htons(strtol(val, &endptr, 0));
 199                         retval = (endptr[0] == '\0');
 200                         break;
 201                 case OPTION_U32:
 202                         *result_u32 = htonl(strtoul(val, &endptr, 0));
 203                         retval = (endptr[0] == '\0');
 204                         break;
 205                 case OPTION_S32:
 206                         *result_u32 = htonl(strtol(val, &endptr, 0));
 207                         retval = (endptr[0] == '\0');
 208                         break;
 209                 default:
 210                         break;
 211                 }
 212                 if (retval)
 213                         attach_option(opt_list, option, opt, length);
 214         } while (retval && option->flags & OPTION_LIST);
 215         return retval;
 216 }
 217
 218 static int read_staticlease(const char *const_line, void *arg)
 219 {
 220
 221         char *line;
 222         char *mac_string;
 223         char *ip_string;
 224         uint8_t *mac_bytes;
 225         uint32_t *ip;
 226
 227
 228         /* Allocate memory for addresses */
 229         mac_bytes = xmalloc(sizeof(unsigned char) * 8);
 230         ip = xmalloc(sizeof(uint32_t));
 231
 232         /* Read mac */
 233         line = (char *) const_line;
 234         mac_string = strtok(line, " \t");
 235         read_mac(mac_string, mac_bytes);
 236
 237         /* Read ip */
 238         ip_string = strtok(NULL, " \t");
 239         read_ip(ip_string, ip);
 240
 241         addStaticLease(arg, mac_bytes, ip);
 242
 243         if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg);
 244
 245         return 1;
 246
 247 }
 248
 249
 250 static const struct config_keyword keywords[] = {
 251         /* keyword      handler   variable address              default */
 252         {"start",       read_ip,  &(server_config.start),       "192.168.0.20"},
 253         {"end",         read_ip,  &(server_config.end),         "192.168.0.254"},
 254         {"interface",   read_str, &(server_config.interface),   "eth0"},
 255         {"option",      read_opt, &(server_config.options),     ""},
 256         {"opt",         read_opt, &(server_config.options),     ""},
 257         {"max_leases",  read_u32, &(server_config.max_leases),  "254"},
 258         {"remaining",   read_yn,  &(server_config.remaining),   "yes"},
 259         {"auto_time",   read_u32, &(server_config.auto_time),   "7200"},
 260         {"decline_time",read_u32, &(server_config.decline_time),"3600"},
 261         {"conflict_time",read_u32,&(server_config.conflict_time),"3600"},
 262         {"offer_time",  read_u32, &(server_config.offer_time),  "60"},
 263         {"min_lease",   read_u32, &(server_config.min_lease),   "60"},
 264         {"lease_file",  read_str, &(server_config.lease_file),  LEASES_FILE},
 265         {"pidfile",     read_str, &(server_config.pidfile),     "/var/run/udhcpd.pid"},
 266         {"notify_file", read_str, &(server_config.notify_file), ""},
 267         {"siaddr",      read_ip,  &(server_config.siaddr),      "0.0.0.0"},
 268         {"sname",       read_str, &(server_config.sname),       ""},
 269         {"boot_file",   read_str, &(server_config.boot_file),   ""},
 270         {"static_lease",read_staticlease, &(server_config.static_leases),       ""},
 271         /*ADDME: static lease */
 272         {"",            NULL,     NULL,                         ""}
 273 };
 274
 275
 276 int read_config(const char *file)
 277 {
 278         FILE *in;
 279         char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
 280         int i, lm = 0;
 281
 282         for (i = 0; keywords[i].keyword[0]; i++)
 283                 if (keywords[i].def[0])
 284                         keywords[i].handler(keywords[i].def, keywords[i].var);
 285
 286         if (!(in = fopen(file, "r"))) {
 287                 bb_error_msg("unable to open config file: %s", file);
 288                 return 0;
 289         }
 290
 291         while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
 292                 char debug_orig[READ_CONFIG_BUF_SIZE];
 293
 294                 lm++;
 295                 if (strchr(buffer, '\n')) *(strchr(buffer, '\n')) = '\0';
 296                 if (ENABLE_FEATURE_UDHCP_DEBUG) strcpy(debug_orig, buffer);
 297                 if (strchr(buffer, '#')) *(strchr(buffer, '#')) = '\0';
 298
 299                 if (!(token = strtok(buffer, " \t"))) continue;
 300                 if (!(line = strtok(NULL, ""))) continue;
 301
 302                 /* eat leading whitespace */
 303                 line = line + strspn(line, " \t=");
 304                 /* eat trailing whitespace */
 305                 for (i = strlen(line); i > 0 && isspace(line[i - 1]); i--);
 306                 line[i] = '\0';
 307
 308                 for (i = 0; keywords[i].keyword[0]; i++)
 309                         if (!strcasecmp(token, keywords[i].keyword))
 310                                 if (!keywords[i].handler(line, keywords[i].var)) {
 311                                         bb_error_msg("failure parsing line %d of %s", lm, file);
 312                                         if (ENABLE_FEATURE_UDHCP_DEBUG)
 313                                                 bb_error_msg("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                 bb_error_msg("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                 bb_error_msg("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                                 bb_error_msg("too many leases while loading %s", file);
 381                                 break;
 382                         }
 383                         i++;
 384                 }
 385         }
 386         DEBUG("Read %d leases", i);
 387         fclose(fp);
 388 }