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 /* on these functions, make sure you datatype matches */
  20 static int read_ip(const char *line, void *arg)
  21 {
  22         struct in_addr *addr = arg;
  23         struct hostent *host;
  24         int retval = 1;
  25
  26         if (!inet_aton(line, addr)) {
  27                 if ((host = gethostbyname(line)))
  28                         addr->s_addr = *((unsigned long *) host->h_addr_list[0]);
  29                 else retval = 0;
  30         }
  31         return retval;
  32 }
  33
  34
  35 static int read_str(const char *line, void *arg)
  36 {
  37         char **dest = arg;
  38
  39         if (*dest) free(*dest);
  40         *dest = strdup(line);
  41
  42         return 1;
  43 }
  44
  45
  46 static int read_u32(const char *line, void *arg)
  47 {
  48         u_int32_t *dest = arg;
  49         char *endptr;
  50         *dest = strtoul(line, &endptr, 0);
  51         return endptr[0] == '\0';
  52 }
  53
  54
  55 static int read_yn(const char *line, void *arg)
  56 {
  57         char *dest = arg;
  58         int retval = 1;
  59
  60         if (!strcasecmp("yes", line))
  61                 *dest = 1;
  62         else if (!strcasecmp("no", line))
  63                 *dest = 0;
  64         else retval = 0;
  65
  66         return retval;
  67 }
  68
  69 #define READ_CONFIG_BUF_SIZE 512        /* domainname may have 254 chars */
  70
  71 /* read a dhcp option and add it to opt_list */
  72 static int read_opt(const char *const_line, void *arg)
  73 {
  74         char line[READ_CONFIG_BUF_SIZE];
  75         struct option_set **opt_list = arg;
  76         char *opt, *val, *endptr;
  77         struct dhcp_option *option;
  78         int retval = 0, length;
  79         char buffer[256];                       /* max opt length */
  80         u_int16_t result_u16;
  81         u_int32_t result_u32;
  82         void *valptr;
  83
  84         if (!(opt = strtok(strcpy(line, const_line), " \t="))) return 0;
  85
  86         for (option = dhcp_options; option->code; option++)
  87                 if (!strcasecmp(option->name, opt))
  88                         break;
  89
  90         if (!option->code) return 0;
  91
  92         do {
  93                 val = strtok(NULL, ", \t");
  94                 if(!val)
  95                         break;
  96                 length = option_lengths[option->flags & TYPE_MASK];
  97                 valptr = NULL;
  98                 switch (option->flags & TYPE_MASK) {
  99                 case OPTION_IP:
 100                         retval = read_ip(val, buffer);
 101                         break;
 102                 case OPTION_IP_PAIR:
 103                         retval = read_ip(val, buffer);
 104                         if (!(val = strtok(NULL, ", \t/-"))) retval = 0;
 105                         if (retval) retval = read_ip(val, buffer + 4);
 106                         break;
 107                 case OPTION_STRING:
 108                         length = strlen(val);
 109                         if (length > 0) {
 110                                 if (length > 254) length = 254;
 111                                 endptr = buffer + length;
 112                                 endptr[0] = 0;
 113                                 valptr = val;
 114                         }
 115                         break;
 116                 case OPTION_BOOLEAN:
 117                         retval = read_yn(val, buffer);
 118                         break;
 119                 case OPTION_U8:
 120                         buffer[0] = strtoul(val, &endptr, 0);
 121                         valptr = buffer;
 122                         break;
 123                 case OPTION_U16:
 124                         result_u16 = htons(strtoul(val, &endptr, 0));
 125                         valptr = &result_u16;
 126                         break;
 127                 case OPTION_S16:
 128                         result_u16 = htons(strtol(val, &endptr, 0));
 129                         valptr = &result_u16;
 130                         break;
 131                 case OPTION_U32:
 132                         result_u32 = htonl(strtoul(val, &endptr, 0));
 133                         valptr = &result_u32;
 134                         break;
 135                 case OPTION_S32:
 136                         result_u32 = htonl(strtol(val, &endptr, 0));
 137                         valptr = &result_u32;
 138                         break;
 139                 default:
 140                         retval = 0;
 141                         break;
 142                 }
 143                 if (valptr) {
 144                         memcpy(buffer, valptr, length);
 145                         retval = (endptr[0] == '\0');
 146                 }
 147                 if (retval)
 148                         attach_option(opt_list, option, buffer, length);
 149                 else
 150                         break;
 151         } while (option->flags & OPTION_LIST);
 152         return retval;
 153 }
 154
 155
 156 static const struct config_keyword keywords[] = {
 157         /* keyword      handler   variable address              default     */
 158         {"start",       read_ip,  &(server_config.start),       "192.168.0.20"},
 159         {"end",         read_ip,  &(server_config.end),         "192.168.0.254"},
 160         {"interface",   read_str, &(server_config.interface),   "eth0"},
 161         {"option",      read_opt, &(server_config.options),     ""},
 162         {"opt",         read_opt, &(server_config.options),     ""},
 163         {"max_leases",  read_u32, &(server_config.max_leases),  "254"},
 164         {"remaining",   read_yn,  &(server_config.remaining),   "yes"},
 165         {"auto_time",   read_u32, &(server_config.auto_time),   "7200"},
 166         {"decline_time",read_u32, &(server_config.decline_time),"3600"},
 167         {"conflict_time",read_u32,&(server_config.conflict_time),"3600"},
 168         {"offer_time",  read_u32, &(server_config.offer_time),  "60"},
 169         {"min_lease",   read_u32, &(server_config.min_lease),   "60"},
 170         {"lease_file",  read_str, &(server_config.lease_file),  LEASES_FILE},
 171         {"pidfile",     read_str, &(server_config.pidfile),     "/var/run/udhcpd.pid"},
 172         {"notify_file", read_str, &(server_config.notify_file), ""},
 173         {"siaddr",      read_ip,  &(server_config.siaddr),      "0.0.0.0"},
 174         {"sname",       read_str, &(server_config.sname),       ""},
 175         {"boot_file",   read_str, &(server_config.boot_file),   ""},
 176         /*ADDME: static lease */
 177         {"",            NULL,     NULL,                         ""}
 178 };
 179
 180
 181 int read_config(const char *file)
 182 {
 183         FILE *in;
 184         char buffer[READ_CONFIG_BUF_SIZE], orig[READ_CONFIG_BUF_SIZE];
 185         char *token, *line;
 186         int i;
 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                 if (strchr(buffer, '\n')) *(strchr(buffer, '\n')) = '\0';
 199                 strcpy(orig, buffer);
 200                 if (strchr(buffer, '#')) *(strchr(buffer, '#')) = '\0';
 201                 token = strtok(buffer, " \t");
 202                 if(!token)
 203                         continue;
 204                 line = strtok(NULL, "");
 205                 if(!line)
 206                         continue;
 207                 while(*line == '=' || isspace(*line))
 208                 line++;
 209                 /* eat trailing whitespace */
 210                 for (i = strlen(line); i > 0 && isspace(line[i - 1]); i--);
 211                 line[i] = '\0';
 212                 if (*line == '\0')
 213                         continue;
 214
 215                 for (i = 0; keywords[i].keyword[0]; i++)
 216                         if (!strcasecmp(token, keywords[i].keyword))
 217                                 if (!keywords[i].handler(line, keywords[i].var)) {
 218                                         LOG(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 }