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 "dhcpd.h"
  15 #include "files.h"
  16 #include "options.h"
  17 #include "common.h"
  18
  19 /*
  20  * Domain names may have 254 chars, and string options can be 254
  21  * chars long. However, 80 bytes will be enough for most, and won't
  22  * hog up memory. If you have a special application, change it
  23  */
  24 #define READ_CONFIG_BUF_SIZE 80
  25
  26 /* on these functions, make sure you datatype matches */
  27 static int read_ip(const char *line, void *arg)
  28 {
  29         struct in_addr *addr = arg;
  30         struct hostent *host;
  31         int retval = 1;
  32
  33         if (!inet_aton(line, addr)) {
  34                 if ((host = gethostbyname(line)))
  35                         addr->s_addr = *((unsigned long *) host->h_addr_list[0]);
  36                 else retval = 0;
  37         }
  38         return retval;
  39 }
  40
  41
  42 static int read_str(const char *line, void *arg)
  43 {
  44         char **dest = arg;
  45
  46         if (*dest) free(*dest);
  47         *dest = strdup(line);
  48
  49         return 1;
  50 }
  51
  52
  53 static int read_u32(const char *line, void *arg)
  54 {
  55         uint32_t *dest = arg;
  56         char *endptr;
  57         *dest = strtoul(line, &endptr, 0);
  58         return endptr[0] == '\0';
  59 }
  60
  61
  62 static int read_yn(const char *line, void *arg)
  63 {
  64         char *dest = arg;
  65         int retval = 1;
  66
  67         if (!strcasecmp("yes", line))
  68                 *dest = 1;
  69         else if (!strcasecmp("no", line))
  70                 *dest = 0;
  71         else retval = 0;
  72
  73         return retval;
  74 }
  75
  76
  77 /* read a dhcp option and add it to opt_list */
  78 static int read_opt(const char *const_line, void *arg)
  79 {
  80         struct option_set **opt_list = arg;
  81         char *opt, *val, *endptr;
  82         struct dhcp_option *option;
  83         int retval = 0, length;
  84         char buffer[8];
  85         char *line;
  86         uint16_t *result_u16 = (uint16_t *) buffer;
  87         uint32_t *result_u32 = (uint32_t *) buffer;
  88
  89         /* Cheat, the only const line we'll actually get is "" */
  90         line = (char *) const_line;
  91         if (!(opt = strtok(line, " \t="))) return 0;
  92
  93         for (option = dhcp_options; option->code; option++)
  94                 if (!strcasecmp(option->name, opt))
  95                         break;
  96
  97         if (!option->code) return 0;
  98
  99         do {
 100                 if (!(val = strtok(NULL, ", \t"))) break;
 101                 length = option_lengths[option->flags & TYPE_MASK];
 102                 retval = 0;
 103                 opt = buffer; /* new meaning for variable opt */
 104                 switch (option->flags & TYPE_MASK) {
 105                 case OPTION_IP:
 106                         retval = read_ip(val, buffer);
 107                         break;
 108                 case OPTION_IP_PAIR:
 109                         retval = read_ip(val, buffer);
 110                         if (!(val = strtok(NULL, ", \t/-"))) retval = 0;
 111                         if (retval) retval = read_ip(val, buffer + 4);
 112                         break;
 113                 case OPTION_STRING:
 114                         length = strlen(val);
 115                         if (length > 0) {
 116                                 if (length > 254) length = 254;
 117                                 opt = val;
 118                                 retval = 1;
 119                         }
 120                         break;
 121                 case OPTION_BOOLEAN:
 122                         retval = read_yn(val, buffer);
 123                         break;
 124                 case OPTION_U8:
 125                         buffer[0] = strtoul(val, &endptr, 0);
 126                         retval = (endptr[0] == '\0');
 127                         break;
 128                 case OPTION_U16:
 129                         *result_u16 = htons(strtoul(val, &endptr, 0));
 130                         retval = (endptr[0] == '\0');
 131                         break;
 132                 case OPTION_S16:
 133                         *result_u16 = htons(strtol(val, &endptr, 0));
 134                         retval = (endptr[0] == '\0');
 135                         break;
 136                 case OPTION_U32:
 137                         *result_u32 = htonl(strtoul(val, &endptr, 0));
 138                         retval = (endptr[0] == '\0');
 139                         break;
 140                 case OPTION_S32:
 141                         *result_u32 = htonl(strtol(val, &endptr, 0));
 142                         retval = (endptr[0] == '\0');
 143                         break;
 144                 default:
 145                         break;
 146                 }
 147                 if (retval)
 148                         attach_option(opt_list, option, opt, length);
 149         } while (retval && option->flags & OPTION_LIST);
 150         return retval;
 151 }
 152
 153
 154 static const struct config_keyword keywords[] = {
 155         /* keyword      handler   variable address              default */
 156         {"start",       read_ip,  &(server_config.start),       "192.168.0.20"},
 157         {"end",         read_ip,  &(server_config.end),         "192.168.0.254"},
 158         {"interface",   read_str, &(server_config.interface),   "eth0"},
 159         {"option",      read_opt, &(server_config.options),     ""},
 160         {"opt",         read_opt, &(server_config.options),     ""},
 161         {"max_leases",  read_u32, &(server_config.max_leases),  "254"},
 162         {"remaining",   read_yn,  &(server_config.remaining),   "yes"},
 163         {"auto_time",   read_u32, &(server_config.auto_time),   "7200"},
 164         {"decline_time",read_u32, &(server_config.decline_time),"3600"},
 165         {"conflict_time",read_u32,&(server_config.conflict_time),"3600"},
 166         {"offer_time",  read_u32, &(server_config.offer_time),  "60"},
 167         {"min_lease",   read_u32, &(server_config.min_lease),   "60"},
 168         {"lease_file",  read_str, &(server_config.lease_file),  LEASES_FILE},
 169         {"pidfile",     read_str, &(server_config.pidfile),     "/var/run/udhcpd.pid"},
 170         {"notify_file", read_str, &(server_config.notify_file), ""},
 171         {"siaddr",      read_ip,  &(server_config.siaddr),      "0.0.0.0"},
 172         {"sname",       read_str, &(server_config.sname),       ""},
 173         {"boot_file",   read_str, &(server_config.boot_file),   ""},
 174         /*ADDME: static lease */
 175         {"",            NULL,     NULL,                         ""}
 176 };
 177
 178
 179 int read_config(const char *file)
 180 {
 181         FILE *in;
 182         char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
 183 #ifdef UDHCP_DEBUG
 184         char orig[READ_CONFIG_BUF_SIZE];
 185 #endif
 186         int i, lm = 0;
 187
 188         for (i = 0; keywords[i].keyword[0]; i++)
 189                 if (keywords[i].def[0])
 190                         keywords[i].handler(keywords[i].def, keywords[i].var);
 191
 192         if (!(in = fopen(file, "r"))) {
 193                 LOG(LOG_ERR, "unable to open config file: %s", file);
 194                 return 0;
 195         }
 196
 197         while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
 198                 lm++;
 199                 if (strchr(buffer, '\n')) *(strchr(buffer, '\n')) = '\0';
 200 #ifdef UDHCP_DEBUG
 201                 strcpy(orig, buffer);
 202 #endif
 203                 if (strchr(buffer, '#')) *(strchr(buffer, '#')) = '\0';
 204
 205                 if (!(token = strtok(buffer, " \t"))) continue;
 206                 if (!(line = strtok(NULL, ""))) continue;
 207
 208                 /* eat leading whitespace */
 209                 line = line + strspn(line, " \t=");
 210                 /* eat trailing whitespace */
 211                 for (i = strlen(line); i > 0 && isspace(line[i - 1]); i--);
 212                 line[i] = '\0';
 213
 214                 for (i = 0; keywords[i].keyword[0]; i++)
 215                         if (!strcasecmp(token, keywords[i].keyword))
 216                                 if (!keywords[i].handler(line, keywords[i].var)) {
 217                                         LOG(LOG_ERR, "Failure parsing line %d of %s", lm, file);
 218                                         DEBUG(LOG_ERR, "unable to parse '%s'", orig);
 219                                         /* reset back to the default value */
 220                                         keywords[i].handler(keywords[i].def, keywords[i].var);
 221                                 }
 222         }
 223         fclose(in);
 224         return 1;
 225 }
 226
 227
 228 void write_leases(void)
 229 {
 230         FILE *fp;
 231         unsigned int i;
 232         char buf[255];
 233         time_t curr = time(0);
 234         unsigned long tmp_time;
 235
 236         if (!(fp = fopen(server_config.lease_file, "w"))) {
 237                 LOG(LOG_ERR, "Unable to open %s for writing", server_config.lease_file);
 238                 return;
 239         }
 240
 241         for (i = 0; i < server_config.max_leases; i++) {
 242                 if (leases[i].yiaddr != 0) {
 243
 244                         /* screw with the time in the struct, for easier writing */
 245                         tmp_time = leases[i].expires;
 246
 247                         if (server_config.remaining) {
 248                                 if (lease_expired(&(leases[i])))
 249                                         leases[i].expires = 0;
 250                                 else leases[i].expires -= curr;
 251                         } /* else stick with the time we got */
 252                         leases[i].expires = htonl(leases[i].expires);
 253                         fwrite(&leases[i], sizeof(struct dhcpOfferedAddr), 1, fp);
 254
 255                         /* Then restore it when done. */
 256                         leases[i].expires = tmp_time;
 257                 }
 258         }
 259         fclose(fp);
 260
 261         if (server_config.notify_file) {
 262                 sprintf(buf, "%s %s", server_config.notify_file, server_config.lease_file);
 263                 system(buf);
 264         }
 265 }
 266
 267
 268 void read_leases(const char *file)
 269 {
 270         FILE *fp;
 271         unsigned int i = 0;
 272         struct dhcpOfferedAddr lease;
 273
 274         if (!(fp = fopen(file, "r"))) {
 275                 LOG(LOG_ERR, "Unable to open %s for reading", file);
 276                 return;
 277         }
 278
 279         while (i < server_config.max_leases && (fread(&lease, sizeof lease, 1, fp) == 1)) {
 280                 /* ADDME: is it a static lease */
 281                 if (lease.yiaddr >= server_config.start && lease.yiaddr <= server_config.end) {
 282                         lease.expires = ntohl(lease.expires);
 283                         if (!server_config.remaining) lease.expires -= time(0);
 284                         if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
 285                                 LOG(LOG_WARNING, "Too many leases while loading %s\n", file);
 286                                 break;
 287                         }
 288                         i++;
 289                 }
 290         }
 291         DEBUG(LOG_INFO, "Read %d leases", i);
 292         fclose(fp);
 293 }