#!/bin/bash

# Configuration Fallbacks. All can(must for some of them) be overwritten by /etc/default/snf-network
TTL=300
# the bind server IP/FQDN
SERVER=""
# this is the .vm.synnefo.live.
# Leave empty if only reverse dns management is needed.
# TODO: make this zone to be instance specific!!!
FZONE=""
# the file with dns authorization keys
KEYFILE=""
MAC2EUI64="/usr/bin/mac2eui64"

source /etc/default/snf-network
source /usr/lib/snf-network/common.sh

if [ -z "$SERVER" -o -z "$FZONE" -o ! -e "$KEYFILE" ]; then
  exit 0
fi

update_dns () {

  if [ "x$GANETI_OP_CODE" = "xOP_INSTANCE_CREATE" ]; then
    update_all add
  elif [ "x$GANETI_OP_CODE" = "xOP_INSTANCE_REMOVE" ]; then
    update_all delete
  elif [ "x$GANETI_OP_CODE" = "xOP_INSTANCE_RENAME" ]; then
    update_all delete
    # Let's override a variable and add ourselves
    GANETI_INSTANCE_NAME=$GANETI_INSTANCE_NEW_NAME
    update_all add
  elif [ "x$GANETI_OP_CODE" = "xOP_INSTANCE_STARTUP" ]; then
    update_all add
  elif [ "x$GANETI_OP_CODE" = "xOP_INSTANCE_SHUTDOWN" ]; then
    update_all delete
  elif [ "x$GANETI_OP_CODE" = "xOP_INSTANCE_REBOOT" ]; then
    update_all add
  elif [ "x$GANETI_OP_CODE" = "xOP_INSTANCE_SET_PARAMS" ]; then
    update_all add
  fi

}


# Query nameserver for entries related to the specific instance
# An example output is the following:
# www.google.com has address 173.194.113.114
# www.google.com has address 173.194.113.115
# www.google.com has address 173.194.113.116
# www.google.com has address 173.194.113.112
# www.google.com has address 173.194.113.113
# www.google.com has IPv6 address 2a00:1450:4001:80b::1012
query_dns () {

  HOSTQ="host -s -R 3 -W 3"
  HOST_IP_ALL=$($HOSTQ $GANETI_INSTANCE_NAME.$FZONE $SERVER | sed -n 's/.*has address //p')
  HOST_IP6_ALL=$($HOSTQ $GANETI_INSTANCE_NAME.$FZONE $SERVER | sed -n 's/.*has IPv6 address //p')

}


# Reset all entries related to the specific instance
# This should be invoced only during instance modification
# because we do not know which nics have been modify
reset_dns () {

  if [ "x$GANETI_OP_CODE" = "xOP_INSTANCE_SET_PARAMS" ]; then
    query_dns
    # This should remove the A, AAAA, CNAME entries
    send_command "update delete $GANETI_INSTANCE_NAME.$FZONE"
    for ip in $HOST_IP_ALL; do
      get_rev4_info $ip
      # This should remove the IPv4 reverse entry
      send_command "update delete $RLPART.$RZONE"
    done
    for ip6 in $HOST_IP6_ALL; do
      get_rev6_info $ip6
      # This should remove the IPv6 reverse entry
      send_command "update delete $R6LPART$R6ZONE."
    done
  fi

}


# Main starts here


# Exit if we do not have instance name.
# It should be exported to hooks for instance related opcodes.
if [ -z "$GANETI_INSTANCE_NAME" ]; then
  exit 0
fi

# This runs only for instance modification
reset_dns

# If GANETI_INSTANCE_NIC_COUNT is not set then nothing happens
FIRST=0
LAST=$((GANETI_INSTANCE_NIC_COUNT - 1))
for idx in $(seq $FIRST $LAST); do
  ip=GANETI_INSTANCE_NIC${idx}_IP
  mac=GANETI_INSTANCE_NIC${idx}_MAC
  mode=GANETI_INSTANCE_NIC${idx}_MODE
  link=GANETI_INSTANCE_NIC${idx}_LINK
  subnet=GANETI_INSTANCE_NIC${idx}_NETWORK_SUBNET
  subnet6=GANETI_INSTANCE_NIC${idx}_NETWORK_SUBNET6
  tags=GANETI_INSTANCE_NIC${idx}_NETWORK_TAGS
  eval IP=\$$ip
  eval MAC=\$$mac
  eval MODE=\$$mode
  eval LINK=\$$link
  eval SUBNET=\$$subnet
  eval SUBNET6=\$$subnet6
  eval TAGS=\$$tags

  for tag in $TAGS; do
    case $tag in
    $DNS_TAG)

      get_rev4_info "$IP"
      get_eui64 "$MAC" "$SUBNET6"
      get_rev6_info "$EUI64"
      $SNF_NETWORK_LOG dnshook "update dns for $GANETI_INSTANCE_NAME $IP $EUI64"
      update_dns

      ;;
    esac

  done

done