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 function 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 function dns_server_list() {
  60         [ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_OK}
  61
  62         local line
  63         local ${NETWORK_CONFIG_DNS_SERVER_PARAMS}
  64
  65         local format="%-20s %-8s"
  66         print "${format}" "SERVER" "PRIORITY"
  67
  68         while read -r line; do
  69                 dns_server_parse_line ${line} || continue
  70
  71                 print "${format}" "${server}" "${priority}"
  72         done < ${DNS_SERVER_CONFIG_FILE}
  73
  74         return ${EXIT_OK}
  75 }
  76
  77 function dns_server_list_sorted() {
  78         [ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_OK}
  79
  80         local servers=$(
  81                 # First get all servers from the configuration file.
  82                 while read -r line; do
  83                         dns_server_parse_line ${line} || continue
  84
  85                         print "%d %s" "${priority}" "${server}"
  86                 done < ${DNS_SERVER_CONFIG_FILE}
  87
  88                 # Then get all dynamically assigned DNS servers.
  89                 dns_server_get_zone_name_servers
  90         )
  91
  92         # Nothing to do if we have got no DNS servers.
  93         isset servers || return ${EXIT_OK}
  94
  95         # Sort everything we have got.
  96         servers=$(sort -g -k1 <<< "${servers}")
  97
  98         # Remove the priority bit.
  99         local server server_list
 100         while read -r priority server; do
 101                 list_append server_list "${server}"
 102         done <<< "${servers}"
 103
 104         # Return the list but remove duplicate entries, keeping
 105         # the first and removing all others.
 106         list_unique ${server_list}
 107
 108         return ${EXIT_OK}
 109 }
 110
 111 function dns_server_add() {
 112         local server=${1}
 113         assert isset server
 114
 115         local priority=${2}
 116         if ! isset priority; then
 117                 priority="${DNS_SERVER_DEFAULT_PRIORITY}"
 118         fi
 119         assert isinteger priority
 120
 121         # Add a new line to the configuration file.
 122         print "server=\"%s\" priority=\"%d\"" "${server}" "${priority}" \
 123                 >> ${DNS_SERVER_CONFIG_FILE}
 124
 125         return ${EXIT_OK}
 126 }
 127
 128 function dns_server_exists() {
 129         local entry=${1}
 130         assert isset entry
 131
 132         [ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_FALSE}
 133
 134         local line ${NETWORK_CONFIG_DNS_SERVER_PARAMS}
 135         while read -r line; do
 136                 dns_server_parse_line ${line} || continue
 137
 138                 [ "${entry}" = "${server}" ] && return ${EXIT_TRUE}
 139         done < ${DNS_SERVER_CONFIG_FILE}
 140
 141         return ${EXIT_FALSE}
 142 }
 143
 144 function dns_server_remove() {
 145         local entry=${1}
 146         assert isset entry
 147
 148         # Check if the DNS server configuration file exists.
 149         [ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_ERROR}
 150
 151         # Create a tempfile.
 152         local tempfile=$(mktemp)
 153
 154         local line ${NETWORK_CONFIG_DNS_SERVER_PARAMS}
 155         while read -r line; do
 156                 dns_server_parse_line ${line} || continue
 157
 158                 # Skip the line with the server we are searching for.
 159                 [ "${entry}" = "${server}" ] && continue
 160
 161                 # Re-add the old line.
 162                 print "${line}"
 163         done < ${DNS_SERVER_CONFIG_FILE} > ${tempfile}
 164
 165         # Overwrite the old content without the entry that has just been removed.
 166         fread "${tempfile}" > ${DNS_SERVER_CONFIG_FILE}
 167
 168         # Remove the temporary file.
 169         rm -f ${tempfile}
 170
 171         return ${EXIT_OK}
 172 }
 173
 174 function dns_server_flush() {
 175         : > ${DNS_SERVER_CONFIG_FILE}
 176 }
 177
 178 function dns_server_parse_line() {
 179         local arg
 180
 181         for arg in ${NETWORK_CONFIG_DNS_SERVER_PARAMS}; do
 182                 assign "${arg}" ""
 183         done
 184
 185         while read -r arg; do
 186                 case "${arg}" in
 187                         server=*)
 188                                 server=$(cli_get_val ${arg})
 189                                 ;;
 190                         priority=*)
 191                                 priority=$(cli_get_val ${arg})
 192                                 ;;
 193                 esac
 194         done <<< "$(args $@)"
 195
 196         # The server address must be set.
 197         isset server || return ${EXIT_ERROR}
 198
 199         # The server address must also be a valid IP address.
 200         ip_is_valid ${server} || return ${EXIT_ERROR}
 201
 202         # If priority is set, it must be an integer number.
 203         if isset priority; then
 204                 isinteger priority || return ${EXIT_ERROR}
 205
 206         # Otherwise assign the default priority.
 207         else
 208                 priority=${DNS_SERVER_DEFAULT_PRIORITY}
 209         fi
 210
 211         return ${EXIT_OK}
 212 }
 213
 214 # Update resolv.conf(5) when initializing the network.
 215 init_register dns_generate_resolvconf
 216
 217 function dns_generate_resolvconf() {
 218         local file=${RESOLV_CONF}
 219
 220         log INFO "Updating resolver configuration..."
 221
 222         config_header "resolver configutation file" > ${file}
 223
 224         if enabled DNS_RANDOMIZE; then
 225                 print "option rotate\n" >> ${file}
 226         fi
 227
 228         # Write search domains to file.
 229         print "# Search domains" >> ${file}
 230
 231         local domain
 232         for domain in $(dns_get_search_domains); do
 233                 print "search ${domain}"
 234         done >> ${file}
 235
 236         print "\n# Nameservers" >> ${file}
 237
 238         # Add the local resolver as the first DNS server if enabled.
 239         if enabled DNS_USE_LOCAL_RESOLVER; then
 240                 print "nameserver ::1" >> ${file}
 241         fi
 242
 243         # Dump all DNS servers.
 244         for server in $(dns_server_list_sorted); do
 245                 print "nameserver ${server}"
 246         done >> ${file}
 247 }
 248
 249 function dns_get_search_domains() {
 250         # Add search domains.
 251         local search_domains="$(unquote ${DNS_SEARCH_DOMAINS})"
 252
 253         # Get search domains from DHCP clients, etc.
 254         local domain proto zone
 255
 256         for zone in $(zones_get_all); do
 257                 for proto in ${IP_SUPPORTED_PROTOCOLS}; do
 258                         domain=$(routing_db_get ${zone} ${proto} domain-name)
 259                         isset domain || continue
 260
 261                         list_append search_domains "${domainname}"
 262                 done
 263         done
 264
 265         # Sort out duplicate entries.
 266         list_unique ${search_domains}
 267 }
 268
 269 function dns_server_get_zone_name_servers() {
 270         local priority proto server servers zone
 271
 272         for zone in $(zones_get_all); do
 273                 for proto in ${IP_SUPPORTED_PROTOCOLS}; do
 274                         priority=$(routing_db_get ${zone} ${proto} domain-name-servers-priority)
 275                         isset priority || priority="${DNS_SERVER_DYNAMIC_PRIORITY}"
 276
 277                         servers=$(routing_db_get ${zone} ${proto} domain-name-servers)
 278                         for server in ${servers}; do
 279                                 print "${priority} ${server}"
 280                         done
 281                 done
 282         done
 283 }