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 <stdio.h>
   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 "debug.h"
  16 #include "dhcpd.h"
  17 #include "files.h"
  18 #include "options.h"
  19 #include "leases.h"
  20
  21 /* on these functions, make sure you datatype matches */
  22 static int read_ip(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                 if ((host = gethostbyname(line)))
  30                         addr->s_addr = *((unsigned long *) host->h_addr_list[0]);
  31                 else retval = 0;
  32         }
  33         return retval;
  34 }
  35
  36
  37 static int read_str(char *line, void *arg)
  38 {
  39         char **dest = arg;
  40
  41         free(*dest);
  42         *dest = strdup(line);
  43
  44         return 1;
  45 }
  46
  47
  48 static int read_u32(char *line, void *arg)
  49 {
  50         u_int32_t *dest = arg;
  51         char *endptr;
  52         *dest = strtoul(line, &endptr, 0);
  53         return endptr[0] == '\0';
  54 }
  55
  56
  57 static int read_yn(char *line, void *arg)
  58 {
  59         char *dest = arg;
  60         int retval = 1;
  61
  62         if (!strcasecmp("yes", line))
  63                 *dest = 1;
  64         else if (!strcasecmp("no", line))
  65                 *dest = 0;
  66         else retval = 0;
  67
  68         return retval;
  69 }
  70
  71
  72 /* read a dhcp option and add it to opt_list */
  73 static int read_opt(char *line, void *arg)
  74 {
  75         struct option_set **opt_list = arg;
  76         char *opt, *val, *endptr;
  77         struct dhcp_option *option = NULL;
  78         int retval = 0, length = 0;
  79         char buffer[255];
  80         u_int16_t result_u16;
  81         u_int32_t result_u32;
  82         int i;
  83
  84         if (!(opt = strtok(line, " \t="))) return 0;
  85
  86         for (i = 0; options[i].code; i++)
  87                 if (!strcmp(options[i].name, opt))
  88                         option = &(options[i]);
  89
  90         if (!option) return 0;
  91
  92         do {
  93                 val = strtok(NULL, ", \t");
  94                 if (val) {
  95                         length = option_lengths[option->flags & TYPE_MASK];
  96                         retval = 0;
  97                         switch (option->flags & TYPE_MASK) {
  98                         case OPTION_IP:
  99                                 retval = read_ip(val, buffer);
 100                                 break;
 101                         case OPTION_IP_PAIR:
 102                                 retval = read_ip(val, buffer);
 103                                 if (!(val = strtok(NULL, ", \t/-"))) retval = 0;
 104                                 if (retval) retval = read_ip(val, buffer + 4);
 105                                 break;
 106                         case OPTION_STRING:
 107                                 length = strlen(val);
 108                                 if (length > 0) {
 109                                         if (length > 254) length = 254;
 110                                         memcpy(buffer, val, length);
 111                                         retval = 1;
 112                                 }
 113                                 break;
 114                         case OPTION_BOOLEAN:
 115                                 retval = read_yn(val, buffer);
 116                                 break;
 117                         case OPTION_U8:
 118                                 buffer[0] = strtoul(val, &endptr, 0);
 119                                 retval = (endptr[0] == '\0');
 120                                 break;
 121                         case OPTION_U16:
 122                                 result_u16 = htons(strtoul(val, &endptr, 0));
 123                                 memcpy(buffer, &result_u16, 2);
 124                                 retval = (endptr[0] == '\0');
 125                                 break;
 126                         case OPTION_S16:
 127                                 result_u16 = htons(strtol(val, &endptr, 0));
 128                                 memcpy(buffer, &result_u16, 2);
 129                                 retval = (endptr[0] == '\0');
 130                                 break;
 131                         case OPTION_U32:
 132                                 result_u32 = htonl(strtoul(val, &endptr, 0));
 133                                 memcpy(buffer, &result_u32, 4);
 134                                 retval = (endptr[0] == '\0');
 135                                 break;
 136                         case OPTION_S32:
 137                                 result_u32 = htonl(strtol(val, &endptr, 0));
 138                                 memcpy(buffer, &result_u32, 4);
 139                                 retval = (endptr[0] == '\0');
 140                                 break;
 141                         default:
 142                                 break;
 143                         }
 144                         if (retval)
 145                                 attach_option(opt_list, option, buffer, length);
 146                 };
 147         } while (val && retval && option->flags & OPTION_LIST);
 148         return retval;
 149 }
 150
 151
 152 static struct config_keyword keywords[] = {
 153         /* keyword[14]  handler   variable address              default[20] */
 154         {"start",       read_ip,  &(server_config.start),       "192.168.0.20"},
 155         {"end",         read_ip,  &(server_config.end),         "192.168.0.254"},
 156         {"interface",   read_str, &(server_config.interface),   "eth0"},
 157         {"option",      read_opt, &(server_config.options),     ""},
 158         {"opt",         read_opt, &(server_config.options),     ""},
 159         {"max_leases",  read_u32, &(server_config.max_leases),  "254"},
 160         {"remaining",   read_yn,  &(server_config.remaining),   "yes"},
 161         {"auto_time",   read_u32, &(server_config.auto_time),   "7200"},
 162         {"decline_time",read_u32, &(server_config.decline_time),"3600"},
 163         {"conflict_time",read_u32,&(server_config.conflict_time),"3600"},
 164         {"offer_time",  read_u32, &(server_config.offer_time),  "60"},
 165         {"min_lease",   read_u32, &(server_config.min_lease),   "60"},
 166         {"lease_file",  read_str, &(server_config.lease_file),  "/var/lib/misc/udhcpd.leases"},
 167         {"pidfile",     read_str, &(server_config.pidfile),     "/var/run/udhcpd.pid"},
 168         {"notify_file", read_str, &(server_config.notify_file), ""},
 169         {"siaddr",      read_ip,  &(server_config.siaddr),      "0.0.0.0"},
 170         {"sname",       read_str, &(server_config.sname),       ""},
 171         {"boot_file",   read_str, &(server_config.boot_file),   ""},
 172         /*ADDME: static lease */
 173         {"",            NULL,     NULL,                         ""}
 174 };
 175
 176
 177 int read_config(char *file)
 178 {
 179         FILE *in;
 180         char buffer[80], orig[80], *token, *line;
 181         int i;
 182
 183         for (i = 0; strlen(keywords[i].keyword); i++)
 184                 if (strlen(keywords[i].def))
 185                         keywords[i].handler(keywords[i].def, keywords[i].var);
 186
 187         if (!(in = fopen(file, "r"))) {
 188                 LOG(LOG_ERR, "unable to open config file: %s", file);
 189                 return 0;
 190         }
 191
 192         while (fgets(buffer, 80, in)) {
 193                 if (strchr(buffer, '\n')) *(strchr(buffer, '\n')) = '\0';
 194                 strncpy(orig, buffer, 80);
 195                 if (strchr(buffer, '#')) *(strchr(buffer, '#')) = '\0';
 196                 token = buffer + strspn(buffer, " \t");
 197                 if (*token == '\0') continue;
 198                 line = token + strcspn(token, " \t=");
 199                 if (*line == '\0') continue;
 200                 *line = '\0';
 201                 line++;
 202
 203                 /* eat leading whitespace */
 204                 line = line + strspn(line, " \t=");
 205                 /* eat trailing whitespace */
 206                 for (i = strlen(line); i > 0 && isspace(line[i - 1]); i--);
 207                 line[i] = '\0';
 208
 209                 for (i = 0; strlen(keywords[i].keyword); i++)
 210                         if (!strcasecmp(token, keywords[i].keyword))
 211                                 if (!keywords[i].handler(line, keywords[i].var)) {
 212                                         LOG(LOG_ERR, "unable to parse '%s'", orig);
 213                                         /* reset back to the default value */
 214                                         keywords[i].handler(keywords[i].def, keywords[i].var);
 215                                 }
 216         }
 217         fclose(in);
 218         return 1;
 219 }
 220
 221
 222 void write_leases(void)
 223 {
 224         FILE *fp;
 225         unsigned int i;
 226         char buf[255];
 227         time_t curr = time(0);
 228         unsigned long lease_time;
 229
 230         if (!(fp = fopen(server_config.lease_file, "w"))) {
 231                 LOG(LOG_ERR, "Unable to open %s for writing", server_config.lease_file);
 232                 return;
 233         }
 234
 235         for (i = 0; i < server_config.max_leases; i++) {
 236                 if (leases[i].yiaddr != 0) {
 237                         if (server_config.remaining) {
 238                                 if (lease_expired(&(leases[i])))
 239                                         lease_time = 0;
 240                                 else lease_time = leases[i].expires - curr;
 241                         } else lease_time = leases[i].expires;
 242                         lease_time = htonl(lease_time);
 243                         fwrite(leases[i].chaddr, 16, 1, fp);
 244                         fwrite(&(leases[i].yiaddr), 4, 1, fp);
 245                         fwrite(&lease_time, 4, 1, fp);
 246                 }
 247         }
 248         fclose(fp);
 249
 250         if (server_config.notify_file) {
 251                 sprintf(buf, "%s %s", server_config.notify_file, server_config.lease_file);
 252                 system(buf);
 253         }
 254 }
 255
 256
 257 void read_leases(char *file)
 258 {
 259         FILE *fp;
 260         unsigned int i = 0;
 261         struct dhcpOfferedAddr lease;
 262
 263         if (!(fp = fopen(file, "r"))) {
 264                 LOG(LOG_ERR, "Unable to open %s for reading", file);
 265                 return;
 266         }
 267
 268         while (i < server_config.max_leases && (fread(&lease, sizeof lease, 1, fp) == 1)) {
 269                 /* ADDME: is it a static lease */
 270                 if (lease.yiaddr >= server_config.start && lease.yiaddr <= server_config.end) {
 271                         lease.expires = ntohl(lease.expires);
 272                         if (!server_config.remaining) lease.expires -= time(0);
 273                         if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
 274                                 LOG(LOG_WARNING, "Too many leases while loading %s\n", file);
 275                                 break;
 276                         }
 277                         i++;
 278                 }
 279         }
 280         DEBUG(LOG_INFO, "Read %d leases", i);
 281         fclose(fp);
 282 }
 283
 284