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package util
import "net"
// IsIPv6 returns true if netIP is IPv6.
func IsIPv6(netIP net.IP) bool {
return netIP != nil && netIP.To4() == nil
}
// IsIPv4 returns true if netIP is IPv4.
func IsIPv4(netIP net.IP) bool {
return netIP != nil && netIP.To4() != nil
}
// LastIPInSubnet gets the last IP in a subnet
func LastIPInSubnet(addr *net.IPNet) (net.IP, error) { //nolint:interfacer
// re-parse to ensure clean network address
_, cidr, err := net.ParseCIDR(addr.String())
if err != nil {
return nil, err
}
ones, bits := cidr.Mask.Size()
if ones == bits {
return cidr.IP, nil
}
for i := range cidr.IP {
cidr.IP[i] = cidr.IP[i] | ^cidr.Mask[i]
}
return cidr.IP, nil
}
// FirstIPInSubnet gets the first IP in a subnet
func FirstIPInSubnet(addr *net.IPNet) (net.IP, error) { //nolint:interfacer
// re-parse to ensure clean network address
_, cidr, err := net.ParseCIDR(addr.String())
if err != nil {
return nil, err
}
ones, bits := cidr.Mask.Size()
if ones == bits {
return cidr.IP, nil
}
cidr.IP[len(cidr.IP)-1]++
return cidr.IP, nil
}
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