package/base-files/files/bin/ipcalc.sh

   1 #!/bin/sh
   2
   3 . /lib/functions/ipv4.sh
   4
   5 PROG="$(basename "$0")"
   6
   7 usage() {
   8     echo "Usage: $PROG address/prefix [ start limit ]" >&2
   9     exit 1
  10 }
  11
  12 if [ $# -eq 0 ]; then
  13     usage
  14 fi
  15
  16 case "$1" in
  17 */*.*)
  18     str2ip ipaddr "${1%/*}" || exit 1
  19     str2ip netmask "${1#*/}" || exit 1
  20     shift
  21     ;;
  22 */*)
  23     str2ip ipaddr "${1%/*}" || exit 1
  24     prefix="${1#*/}"
  25     assert_uint32 "$prefix" || exit 1
  26     if [ "$prefix" -gt 32 ]; then
  27         printf "Prefix out of range (%s)\n" "$prefix" >&2
  28         exit 1
  29     fi
  30     netmask=$(((0xffffffff << (32 - prefix)) & 0xffffffff))
  31     shift
  32     ;;
  33 *)
  34     str2ip ipaddr "$1" || exit 1
  35     str2ip netmask "$2" || exit 1
  36     shift 2
  37     ;;
  38 esac
  39
  40 if [ $# -ne 0 ] && [ $# -ne 2 ]; then
  41     usage
  42 fi
  43
  44 if ! bitcount prefix "$netmask"; then
  45     printf "Invalid netmask (%s)\n" "$netmask" >&2
  46     exit 1
  47 fi
  48
  49 # complement of the netmask, i.e. the hostmask
  50 hostmask=$((netmask ^ 0xffffffff))
  51 network=$((ipaddr & netmask))
  52 broadcast=$((network | hostmask))
  53
  54 ip2str IP "$ipaddr"
  55 ip2str NETMASK "$netmask"
  56 ip2str NETWORK "$network"
  57
  58 echo "IP=$IP"
  59 echo "NETMASK=$NETMASK"
  60 if [ "$prefix" -le 30 ]; then
  61     ip2str BROADCAST "$broadcast"
  62     echo "BROADCAST=$BROADCAST"
  63 fi
  64 echo "NETWORK=$NETWORK"
  65 echo "PREFIX=$prefix"
  66
  67 [ $# -eq 0 ] && exit 0
  68
  69 if [ "$prefix" -le 30 ]; then
  70     lower=$((network + 1))
  71 else
  72     lower="$network"
  73 fi
  74
  75 start="$1"
  76 assert_uint32 "$start" || exit 1
  77 start=$((network | (start & hostmask)))
  78 [ "$start" -lt "$lower" ] && start="$lower"
  79 [ "$start" -eq "$ipaddr" ] && start=$((start + 1))
  80
  81 if [ "$prefix" -le 30 ]; then
  82     upper=$(((network | hostmask) - 1))
  83 else
  84     upper="$network"
  85 fi
  86
  87 range="$2"
  88 assert_uint32 "$range" || exit 1
  89 end=$((start + range - 1))
  90 [ "$end" -gt "$upper" ] && end="$upper"
  91 [ "$end" -eq "$ipaddr" ] && end=$((end - 1))
  92
  93 if [ "$start" -gt "$end" ]; then
  94     echo "network ($NETWORK/$prefix) too small" >&2
  95     exit 1
  96 fi
  97
  98 ip2str START "$start"
  99 ip2str END "$end"
 100
 101 if [ "$start" -le "$ipaddr" ] && [ "$ipaddr" -le "$end" ]; then
 102     echo "error: address $IP inside range $START..$END" >&2
 103     exit 1
 104 fi
 105
 106 echo "START=$START"
 107 echo "END=$END"
 108
 109 exit 0