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

   1 #!/bin/sh
   2
   3 . /lib/functions/ipv4.sh
   4
   5 PROG="$(basename "$0")"
   6
   7 # wrapper to convert an integer to an address, unless we're using
   8 # decimal output format.
   9 # hook for library function
  10 _ip2str() {
  11     local var="$1" n="$2"
  12     assert_uint32 "$n" || exit 1
  13
  14     if [ "$decimal" -ne 0 ]; then
  15         export -- "$var=$n"
  16     elif [ "$hexadecimal" -ne 0 ]; then
  17         export -- "$var=$(printf "%x" "$n")"
  18     else
  19         ip2str "$@"
  20     fi
  21 }
  22
  23 usage() {
  24     echo "Usage: $PROG [ -d | -x ] address/prefix [ start limit ]" >&2
  25     exit 1
  26 }
  27
  28 decimal=0
  29 hexadecimal=0
  30 if [ "$1" = "-d" ]; then
  31     decimal=1
  32     shift
  33 elif [ "$1" = "-x" ]; then
  34     hexadecimal=1
  35     shift
  36 fi
  37
  38 if [ $# -eq 0 ]; then
  39     usage
  40 fi
  41
  42 case "$1" in
  43 */*.*)
  44     # data is n.n.n.n/m.m.m.m format, like on a Cisco router
  45     str2ip ipaddr "${1%/*}" || exit 1
  46     str2ip netmask "${1#*/}" || exit 1
  47     shift
  48     ;;
  49 */*)
  50     # more modern prefix notation of n.n.n.n/p
  51     str2ip ipaddr "${1%/*}" || exit 1
  52     prefix="${1#*/}"
  53     assert_uint32 "$prefix" || exit 1
  54     if [ "$prefix" -gt 32 ]; then
  55         printf "Prefix out of range (%s)\n" "$prefix" >&2
  56         exit 1
  57     fi
  58     prefix2netmask netmask "$prefix" || exit 1
  59     shift
  60     ;;
  61 *)
  62     # address and netmask as two separate arguments
  63     str2ip ipaddr "$1" || exit 1
  64     str2ip netmask "$2" || exit 1
  65     shift 2
  66     ;;
  67 esac
  68
  69 # we either have no arguments left, or we have a range start and length
  70 if [ $# -ne 0 ] && [ $# -ne 2 ]; then
  71     usage
  72 fi
  73
  74 if ! bitcount prefix "$netmask"; then
  75     printf "Invalid netmask (%s)\n" "$netmask" >&2
  76     exit 1
  77 fi
  78
  79 # complement of the netmask, i.e. the hostmask
  80 hostmask=$((netmask ^ 0xffffffff))
  81 network=$((ipaddr & netmask))
  82 broadcast=$((network | hostmask))
  83 count=$((hostmask + 1))
  84
  85 _ip2str IP "$ipaddr"
  86 _ip2str NETMASK "$netmask"
  87 _ip2str NETWORK "$network"
  88
  89 echo "IP=$IP"
  90 echo "NETMASK=$NETMASK"
  91 # don't include this-network or broadcast addresses
  92 if [ "$prefix" -le 30 ]; then
  93     _ip2str BROADCAST "$broadcast"
  94     echo "BROADCAST=$BROADCAST"
  95 fi
  96 echo "NETWORK=$NETWORK"
  97 echo "PREFIX=$prefix"
  98 echo "COUNT=$count"
  99
 100 # if there's no range, we're done
 101 [ $# -eq 0 ] && exit 0
 102
 103 if [ "$prefix" -le 30 ]; then
 104     lower=$((network + 1))
 105 else
 106     lower="$network"
 107 fi
 108
 109 start="$1"
 110 assert_uint32 "$start" || exit 1
 111 start=$((network | (start & hostmask)))
 112 [ "$start" -lt "$lower" ] && start="$lower"
 113 [ "$start" -eq "$ipaddr" ] && start=$((start + 1))
 114
 115 if [ "$prefix" -le 30 ]; then
 116     upper=$(((network | hostmask) - 1))
 117 else
 118     upper="$network"
 119 fi
 120
 121 range="$2"
 122 assert_uint32 "$range" || exit 1
 123 end=$((start + range - 1))
 124 [ "$end" -gt "$upper" ] && end="$upper"
 125 [ "$end" -eq "$ipaddr" ] && end=$((end - 1))
 126
 127 if [ "$start" -gt "$end" ]; then
 128     echo "network ($NETWORK/$prefix) too small" >&2
 129     exit 1
 130 fi
 131
 132 _ip2str START "$start"
 133 _ip2str END "$end"
 134
 135 if [ "$start" -le "$ipaddr" ] && [ "$ipaddr" -le "$end" ]; then
 136     echo "error: address $IP inside range $START..$END" >&2
 137     exit 1
 138 fi
 139
 140 echo "START=$START"
 141 echo "END=$END"
 142
 143 exit 0