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
  13 #include "dhcpd.h"
  14 #include "files.h"
  15 #include "options.h"
  16 #include "common.h"
  17
  18 /* on these functions, make sure you datatype matches */
  19 static int read_ip(const char *line, void *arg)
  20 {
  21         struct in_addr *addr = arg;
  22         struct hostent *host;
  23         int retval = 1;
  24
  25         if (!inet_aton(line, addr)) {
  26                 if ((host = gethostbyname(line)))
  27                         addr->s_addr = *((unsigned long *) host->h_addr_list[0]);
  28                 else retval = 0;
  29         }
  30         return retval;
  31 }
  32
  33
  34 static int read_str(const char *line, void *arg)
  35 {
  36         char **dest = arg;
  37
  38         if (*dest) free(*dest);
  39         *dest = strdup(line);
  40
  41         return 1;
  42 }
  43
  44
  45 static int read_u32(const char *line, void *arg)
  46 {
  47         u_int32_t *dest = arg;
  48         char *endptr;
  49         *dest = strtoul(line, &endptr, 0);
  50         return endptr[0] == '\0';
  51 }
  52
  53
  54 static int read_yn(const char *line, void *arg)
  55 {
  56         char *dest = arg;
  57         int retval = 1;
  58
  59         if (!strcasecmp("yes", line))
  60                 *dest = 1;
  61         else if (!strcasecmp("no", line))
  62                 *dest = 0;
  63         else retval = 0;
  64
  65         return retval;
  66 }
  67
  68 #define READ_CONFIG_BUF_SIZE 512        /* domainname may have 254 chars */
  69
  70 /* read a dhcp option and add it to opt_list */
  71 static int read_opt(const char *const_line, void *arg)
  72 {
  73     char line[READ_CONFIG_BUF_SIZE];
  74         struct option_set **opt_list = arg;
  75         char *opt, *val, *endptr;
  76     struct dhcp_option *option;
  77     int retval = 0, length;
  78     char buffer[256];                       /* max opt length */
  79         u_int16_t result_u16;
  80         u_int32_t result_u32;
  81     void *valptr;
  82
  83     if ((opt = strtok(strcpy(line, const_line), " \t="))) {
  84
  85         for (option = options; option->code; option++)
  86                 if (!strcasecmp(option->name, opt))
  87                         break;
  88
  89         if (option->code) do {
  90                 val = strtok(NULL, ", \t");
  91                 if(!val)
  92                         break;
  93                         length = option_lengths[option->flags & TYPE_MASK];
  94                 valptr = NULL;
  95                         switch (option->flags & TYPE_MASK) {
  96                         case OPTION_IP:
  97                                 retval = read_ip(val, buffer);
  98                                 break;
  99                         case OPTION_IP_PAIR:
 100                                 retval = read_ip(val, buffer);
 101                                 if (!(val = strtok(NULL, ", \t/-"))) retval = 0;
 102                                 if (retval) retval = read_ip(val, buffer + 4);
 103                                 break;
 104                         case OPTION_STRING:
 105                                 length = strlen(val);
 106                                 if (length > 0) {
 107                                         if (length > 254) length = 254;
 108                                 endptr = buffer + length;
 109                                 endptr[0] = 0;
 110                                 valptr = val;
 111                                 }
 112                                 break;
 113                         case OPTION_BOOLEAN:
 114                                 retval = read_yn(val, buffer);
 115                                 break;
 116                         case OPTION_U8:
 117                                 buffer[0] = strtoul(val, &endptr, 0);
 118                         valptr = buffer;
 119                                 break;
 120                         case OPTION_U16:
 121                                 result_u16 = htons(strtoul(val, &endptr, 0));
 122                         valptr = &result_u16;
 123                                 break;
 124                         case OPTION_S16:
 125                                 result_u16 = htons(strtol(val, &endptr, 0));
 126                         valptr = &result_u16;
 127                                 break;
 128                         case OPTION_U32:
 129                                 result_u32 = htonl(strtoul(val, &endptr, 0));
 130                         valptr = &result_u32;
 131                                 break;
 132                         case OPTION_S32:
 133                                 result_u32 = htonl(strtol(val, &endptr, 0));
 134                         valptr = &result_u32;
 135                                 break;
 136                         default:
 137                         retval = 0;
 138                                 break;
 139                         }
 140                 if(valptr) {
 141                         memcpy(buffer, valptr, length);
 142                         retval = (endptr[0] == '\0');
 143                 }
 144                         if (retval)
 145                                 attach_option(opt_list, option, buffer, length);
 146                 else
 147                         break;
 148         } while (option->flags & OPTION_LIST);
 149     }
 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], orig[READ_CONFIG_BUF_SIZE];
 183         char *token, *line;
 184         int i;
 185
 186         for (i = 0; keywords[i].keyword[0]; i++)
 187                 if (keywords[i].def[0])
 188                         keywords[i].handler(keywords[i].def, keywords[i].var);
 189
 190         if (!(in = fopen(file, "r"))) {
 191                 LOG(LOG_ERR, "unable to open config file: %s", file);
 192                 return 0;
 193         }
 194
 195         while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
 196                 if (strchr(buffer, '\n')) *(strchr(buffer, '\n')) = '\0';
 197                 strcpy(orig, buffer);
 198                 if (strchr(buffer, '#')) *(strchr(buffer, '#')) = '\0';
 199                 token = strtok(buffer, " \t");
 200                 if(!token)
 201                         continue;
 202                 line = strtok(NULL, "");
 203                 if(!line)
 204                         continue;
 205                 while(*line == '=' || isspace(*line))
 206                 line++;
 207                 /* eat trailing whitespace */
 208                 for (i = strlen(line); i > 0 && isspace(line[i - 1]); i--);
 209                 line[i] = '\0';
 210                 if (*line == '\0')
 211                         continue;
 212
 213                 for (i = 0; keywords[i].keyword[0]; i++)
 214                         if (!strcasecmp(token, keywords[i].keyword))
 215                                 if (!keywords[i].handler(line, keywords[i].var)) {
 216                                         LOG(LOG_ERR, "unable to parse '%s'", orig);
 217                                         /* reset back to the default value */
 218                                         keywords[i].handler(keywords[i].def, keywords[i].var);
 219                                 }
 220         }
 221         fclose(in);
 222         return 1;
 223 }
 224
 225
 226 void write_leases(void)
 227 {
 228         FILE *fp;
 229         unsigned int i;
 230         char buf[255];
 231         time_t curr = time(0);
 232         unsigned long lease_time;
 233
 234         if (!(fp = fopen(server_config.lease_file, "w"))) {
 235                 LOG(LOG_ERR, "Unable to open %s for writing", server_config.lease_file);
 236                 return;
 237         }
 238
 239         for (i = 0; i < server_config.max_leases; i++) {
 240                 struct dhcpOfferedAddr lease;
 241                 if (leases[i].yiaddr != 0) {
 242                         if (server_config.remaining) {
 243                                 if (lease_expired(&(leases[i])))
 244                                         lease_time = 0;
 245                                 else lease_time = leases[i].expires - curr;
 246                         } else lease_time = leases[i].expires;
 247                         lease.expires = htonl(lease_time);
 248                         memcpy(lease.chaddr, leases[i].chaddr, 16);
 249                         lease.yiaddr = leases[i].yiaddr;
 250                         fwrite(leases, sizeof(lease), 1, fp);
 251                 }
 252         }
 253         fclose(fp);
 254
 255         if (server_config.notify_file) {
 256                 sprintf(buf, "%s %s", server_config.notify_file, server_config.lease_file);
 257                 system(buf);
 258         }
 259 }
 260
 261
 262 void read_leases(const char *file)
 263 {
 264         FILE *fp;
 265         unsigned int i = 0;
 266         struct dhcpOfferedAddr lease;
 267
 268         if (!(fp = fopen(file, "r"))) {
 269                 LOG(LOG_ERR, "Unable to open %s for reading", file);
 270                 return;
 271         }
 272
 273         while (i < server_config.max_leases && (fread(&lease, sizeof lease, 1, fp) == 1)) {
 274                 /* ADDME: is it a static lease */
 275                 if (lease.yiaddr >= server_config.start && lease.yiaddr <= server_config.end) {
 276                         lease.expires = ntohl(lease.expires);
 277                         if (!server_config.remaining) lease.expires -= time(0);
 278                         if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
 279                                 LOG(LOG_WARNING, "Too many leases while loading %s\n", file);
 280                                 break;
 281                         }
 282                         i++;
 283                 }
 284         }
 285         DEBUG(LOG_INFO, "Read %d leases", i);
 286         fclose(fp);
 287 }