Bash functions for IPv4 network calculations

ipv4.sh

ip2int()
{
  local a b c d
  { IFS=. read a b c d; } <<< $1
  echo $(((((((a << 8) | b) << 8) | c) << 8) | d))
}

int2ip()
{
  local ui32=$1; shift
  local ip n
  for n in 1 2 3 4; do
    ip=$((ui32 & 0xff))${ip:+.}$ip
    ui32=$((ui32 >> 8))
  done
  echo $ip
}

netmask()
{
  local mask=$((0xffffffff << (32 - $1))); shift
  int2ip $mask
}

broadcast()
{
  local addr=$(ip2int $1); shift
  local mask=$((0xffffffff << (32 -$1))); shift
  int2ip $((addr | ~mask))
}

network()
{
  local addr=$(ip2int $1); shift
  local mask=$((0xffffffff << (32 -$1))); shift
  int2ip $((addr & mask))
}