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_CONFIG_FILE_PARAMS="${NETWORK_CONFIG_FILE_PARAMS} DNS_USE_LOCAL_RESOLVER"
  25
  26 # Set this option to true if the DNS servers should be queried in a random order.
  27 # This is useful to load balance between multiple servers.
  28 DNS_RANDOMIZE=false
  29 NETWORK_CONFIG_FILE_PARAMS="${NETWORK_CONFIG_FILE_PARAMS} DNS_RANDOMIZE"
  30
  31 DNS_SERVER_CONFIG_FILE="${NETWORK_CONFIG_DIR}/dns-servers"
  32
  33 # Path to the configuration file of the DNS resolver.
  34 RESOLV_CONF="/etc/resolv.conf"
  35
  36 function dns_get_hostname() {
  37         local address=${1}
  38         assert isset address
  39
  40         (
  41                 unset HOSTNAME
  42                 eval $(ipcalc -h ${address} 2>/dev/null)
  43                 echo "${HOSTNAME}"
  44         )
  45 }
  46
  47 function __dns_server_println() {
  48         local server=${1}
  49         local priority=${2}
  50
  51         print "%-20s %s" "${server}" "${priority}"
  52 }
  53
  54 function __dns_server_sort() {
  55         sort -k2 -u -g
  56 }
  57
  58 function dns_server_list() {
  59         [ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_OK}
  60
  61         local server priority
  62         while read server priority; do
  63                 if [ -n "${server}" ] && [ -n "${priority}" ]; then
  64                         __dns_server_println "${server}" "${priority}"
  65                 fi
  66         done < ${DNS_SERVER_CONFIG_FILE} | __dns_server_sort
  67 }
  68
  69 function dns_server_add() {
  70         local server=${1}
  71         assert isset server
  72
  73         local priority=${2}
  74         if ! isset priority; then
  75                 priority=20
  76         fi
  77         assert isinteger priority
  78
  79         (
  80                 dns_server_list
  81                 __dns_server_println "${server}" "${priority}"
  82         ) | __dns_server_sort > ${DNS_SERVER_CONFIG_FILE}.new
  83
  84         mv ${DNS_SERVER_CONFIG_FILE}{.new,}
  85 }
  86
  87 function dns_server_remove() {
  88         local server=${1}
  89         assert isset server
  90
  91         local entry priority
  92         local entries=$(dns_server_list)
  93
  94         while read entry priority; do
  95                 [ "${entry}" = "${server}" ] && continue
  96                 __dns_server_println "${server}" "${priority}"
  97         done <<< ${entries} | __dns_server_sort > ${DNS_SERVER_CONFIG_FILE}
  98 }
  99
 100 function dns_server_flush() {
 101         : > ${DNS_SERVER_CONFIG_FILE}
 102 }
 103
 104 function dns_generate_resolvconf() {
 105         local file=${RESOLV_CONF}
 106
 107         log INFO "Updating resolver configuration..."
 108
 109         config_header "resolver configutation file" > ${file}
 110
 111         if enabled DNS_RANDOMIZE; then
 112                 print "option rotate\n" >> ${file}
 113         fi
 114
 115         # XXX Add search domain.
 116
 117         # Add the local resolver as the first DNS server if enabled.
 118         if enabled DNS_USE_LOCAL_RESOLVER; then
 119                 print "nameserver ::1" >> ${file}
 120         fi
 121
 122         # Dump all DNS servers (if any).
 123         local server priority
 124         dns_server_list | while read server priority; do
 125                 print "nameserver ${server}"
 126         done >> ${file}
 127 }