src/functions/functions.dns

   1 #!/bin/bash
   2 ###############################################################################
   3 #                                                                             #
   4 # IPFire.org - A linux based firewall                                         #
   5 # Copyright (C) 2012  IPFire Network Development Team                         #
   6 #                                                                             #
   7 # This program is free software: you can redistribute it and/or modify        #
   8 # it under the terms of the GNU General Public License as published by        #
   9 # the Free Software Foundation, either version 3 of the License, or           #
  10 # (at your option) any later version.                                         #
  11 #                                                                             #
  12 # This program is distributed in the hope that it will be useful,             #
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of              #
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
  15 # GNU General Public License for more details.                                #
  16 #                                                                             #
  17 # You should have received a copy of the GNU General Public License           #
  18 # along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
  19 #                                                                             #
  20 ###############################################################################
  21
  22 # Set this to true if localhost should be added as the first DNS server.
  23 DNS_USE_LOCAL_RESOLVER=true
  24 NETWORK_SETTINGS_FILE_PARAMS="${NETWORK_SETTINGS_FILE_PARAMS} DNS_USE_LOCAL_RESOLVER"
  25
  26 # Set this option to true if the DNS servers should be queried in a random order.
  27 # This is useful to load balance between multiple servers.
  28 DNS_RANDOMIZE=false
  29 NETWORK_SETTINGS_FILE_PARAMS="${NETWORK_SETTINGS_FILE_PARAMS} DNS_RANDOMIZE"
  30
  31 DNS_SEARCH_DOMAINS=""
  32 NETWORK_SETTINGS_FILE_PARAMS="${NETWORK_SETTINGS_FILE_PARAMS} DNS_SEARCH_DOMAINS"
  33
  34 # Set this option to true if the DNS servers should be advertised by
  35 # radvd.
  36 DNS_ADVERTISE_SERVERS="true"
  37
  38 DNS_SERVER_CONFIG_FILE="${NETWORK_CONFIG_DIR}/dns-servers"
  39 NETWORK_CONFIG_DNS_SERVER_PARAMS="server priority"
  40
  41 # Set the default priority for DNS servers.
  42 DNS_SERVER_DEFAULT_PRIORITY="100"
  43 DNS_SERVER_DYNAMIC_PRIORITY="10"
  44
  45 # Path to the configuration file of the DNS resolver.
  46 RESOLV_CONF="/etc/resolv.conf"
  47
  48 dns_get_hostname() {
  49         local address=${1}
  50         assert isset address
  51
  52         (
  53                 unset HOSTNAME
  54                 eval $(ipcalc -h ${address} 2>/dev/null)
  55                 echo "${HOSTNAME}"
  56         )
  57 }
  58
  59 dns_server_list() {
  60         [ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_OK}
  61
  62         local line
  63         local ${NETWORK_CONFIG_DNS_SERVER_PARAMS}
  64         while read line; do
  65                 dns_server_parse_line ${line} || continue
  66
  67                 print "${server}"
  68         done < ${DNS_SERVER_CONFIG_FILE}
  69
  70         return ${EXIT_OK}
  71 }
  72
  73 dns_server_list_sorted() {
  74         [ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_OK}
  75
  76         local servers=$(
  77                 # First get all servers from the configuration file.
  78                 while read -r line; do
  79                         dns_server_parse_line ${line} || continue
  80
  81                         print "%d %s" "${priority}" "${server}"
  82                 done < ${DNS_SERVER_CONFIG_FILE}
  83
  84                 # Then get all dynamically assigned DNS servers.
  85                 dns_server_get_zone_name_servers
  86         )
  87
  88         # Nothing to do if we have got no DNS servers.
  89         isset servers || return ${EXIT_OK}
  90
  91         # Sort everything we have got.
  92         servers=$(sort -g -k1 <<< "${servers}")
  93
  94         # Remove the priority bit.
  95         local server server_list
  96         while read -r priority server; do
  97                 list_append server_list "${server}"
  98         done <<< "${servers}"
  99
 100         # Return the list but remove duplicate entries, keeping
 101         # the first and removing all others.
 102         list_unique ${server_list}
 103
 104         return ${EXIT_OK}
 105 }
 106
 107 dns_server_show() {
 108         [ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_OK}
 109
 110         local line
 111         local ${NETWORK_CONFIG_DNS_SERVER_PARAMS}
 112
 113         local format="%-20s %-8s"
 114         print "${format}" "SERVER" "PRIORITY"
 115
 116         while read -r line; do
 117                 dns_server_parse_line ${line} || continue
 118
 119                 print "${format}" "${server}" "${priority}"
 120         done < ${DNS_SERVER_CONFIG_FILE}
 121
 122         return ${EXIT_OK}
 123 }
 124
 125 dns_server_add() {
 126         local server=${1}
 127         assert isset server
 128
 129         local priority=${2}
 130         if ! isset priority; then
 131                 priority="${DNS_SERVER_DEFAULT_PRIORITY}"
 132         fi
 133         assert isinteger priority
 134
 135         # Add a new line to the configuration file.
 136         print "server=\"%s\" priority=\"%d\"" "${server}" "${priority}" \
 137                 >> ${DNS_SERVER_CONFIG_FILE}
 138
 139         return ${EXIT_OK}
 140 }
 141
 142 dns_server_exists() {
 143         local entry=${1}
 144         assert isset entry
 145
 146         [ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_FALSE}
 147
 148         local line ${NETWORK_CONFIG_DNS_SERVER_PARAMS}
 149         while read -r line; do
 150                 dns_server_parse_line ${line} || continue
 151
 152                 [ "${entry}" = "${server}" ] && return ${EXIT_TRUE}
 153         done < ${DNS_SERVER_CONFIG_FILE}
 154
 155         return ${EXIT_FALSE}
 156 }
 157
 158 dns_server_remove() {
 159         local entry=${1}
 160         assert isset entry
 161
 162         # Check if the DNS server configuration file exists.
 163         [ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_ERROR}
 164
 165         # Create a tempfile.
 166         local tempfile=$(mktemp)
 167
 168         local line ${NETWORK_CONFIG_DNS_SERVER_PARAMS}
 169         while read -r line; do
 170                 dns_server_parse_line ${line} || continue
 171
 172                 # Skip the line with the server we are searching for.
 173                 [ "${entry}" = "${server}" ] && continue
 174
 175                 # Re-add the old line.
 176                 print "${line}"
 177         done < ${DNS_SERVER_CONFIG_FILE} > ${tempfile}
 178
 179         # Overwrite the old content without the entry that has just been removed.
 180         fread "${tempfile}" > ${DNS_SERVER_CONFIG_FILE}
 181
 182         # Remove the temporary file.
 183         rm -f ${tempfile}
 184
 185         return ${EXIT_OK}
 186 }
 187
 188 dns_server_flush() {
 189         : > ${DNS_SERVER_CONFIG_FILE}
 190
 191         # Re-generate resolv.conf
 192         dns_generate_resolvconf
 193 }
 194
 195 dns_server_parse_line() {
 196         local arg
 197
 198         for arg in ${NETWORK_CONFIG_DNS_SERVER_PARAMS}; do
 199                 assign "${arg}" ""
 200         done
 201
 202         while read -r arg; do
 203                 case "${arg}" in
 204                         server=*)
 205                                 server=$(cli_get_val "${arg}")
 206                                 ;;
 207                         priority=*)
 208                                 priority=$(cli_get_val "${arg}")
 209                                 ;;
 210                 esac
 211         done <<< "$(args "$@")"
 212
 213         # The server address must be set.
 214         isset server || return ${EXIT_ERROR}
 215
 216         # The server address must also be a valid IP address.
 217         ip_is_valid ${server} || return ${EXIT_ERROR}
 218
 219         # If priority is set, it must be an integer number.
 220         if isset priority; then
 221                 isinteger priority || return ${EXIT_ERROR}
 222
 223         # Otherwise assign the default priority.
 224         else
 225                 priority=${DNS_SERVER_DEFAULT_PRIORITY}
 226         fi
 227
 228         return ${EXIT_OK}
 229 }
 230
 231 # This function should be called after any configuration
 232 # changes have been made to the DNS servers.
 233 dns_server_update() {
 234         # Regenerate /etc/resolv.conf
 235         dns_generate_resolvconf
 236
 237         # Restart radvd which propagates IPv6 DNS servers
 238         radvd_update
 239 }
 240
 241 dns_generate_resolvconf() {
 242         local file=${RESOLV_CONF}
 243
 244         log INFO "Updating resolver configuration..."
 245
 246         config_header "resolver configutation file" > ${file}
 247
 248         # Always enable EDNS0
 249         print "option edns0\n" >> "${file}"
 250
 251         if enabled DNS_RANDOMIZE; then
 252                 print "option rotate\n" >> ${file}
 253         fi
 254
 255         # Write search domains to file.
 256         print "# Search domains" >> ${file}
 257
 258         local domain
 259         for domain in $(dns_get_search_domains); do
 260                 print "search ${domain}"
 261         done >> ${file}
 262
 263         print "\n# Nameservers" >> ${file}
 264
 265         # Add the local resolver as the first DNS server if enabled.
 266         if enabled DNS_USE_LOCAL_RESOLVER; then
 267                 print "nameserver ::1" >> ${file}
 268         fi
 269
 270         # Dump all DNS servers.
 271         for server in $(dns_server_list_sorted); do
 272                 print "nameserver ${server}"
 273         done >> ${file}
 274 }
 275
 276 dns_get_search_domains() {
 277         # Add search domains.
 278         local search_domains="$(unquote ${DNS_SEARCH_DOMAINS})"
 279
 280         # Get search domains from DHCP clients, etc.
 281         local domain proto zone
 282
 283         for zone in $(zones_get_all); do
 284                 for proto in ${IP_SUPPORTED_PROTOCOLS}; do
 285                         domain="$(db_get "${zone}/${proto}/domain-name")"
 286                         isset domain || continue
 287
 288                         list_append search_domains "${domainname}"
 289                 done
 290         done
 291
 292         # Add our own domain
 293         list_append search_domains "$(config_domainname)"
 294
 295         # Sort out duplicate entries.
 296         list_unique ${search_domains}
 297 }
 298
 299 dns_server_get_zone_name_servers() {
 300         local priority proto server servers zone
 301
 302         for zone in $(zones_get_all); do
 303                 for proto in ${IP_SUPPORTED_PROTOCOLS}; do
 304                         priority="$(db_get "${zone}/${proto}/domain-name-servers-priority")"
 305                         isset priority || priority="${DNS_SERVER_DYNAMIC_PRIORITY}"
 306
 307                         servers="$(db_get "${zone}/${proto}/domain-name-servers")"
 308                         for server in ${servers}; do
 309                                 print "${priority} ${server}"
 310                         done
 311                 done
 312         done
 313 }