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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.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
}
// NormalizeIP will transform the given ip to the 4 byte len ipv4 if possible
func NormalizeIP(ip *net.IP) {
ipv4 := ip.To4()
if ipv4 != nil {
*ip = ipv4
}
}
// GetLocalIP returns the first non loopback local IPv4 of the host.
// If no ipv4 address is found it may return an ipv6 address.
// When no ip is found and empty string is returned.
func GetLocalIP() string {
return GetLocalIPExcluding(nil)
}
// GetLocalIPExcluding returns the first non loopback local IPv4 of the host.
// If no ipv4 address is found it may return an ipv6 address.
// Additionally you can specify a list of ips that should not be returned.
// When no ip is found and empty string is returned.
func GetLocalIPExcluding(exclude []net.IP) string {
addrs, err := net.InterfaceAddrs()
if err != nil {
return ""
}
ip := ""
outer:
for _, address := range addrs {
// check the address type and if it is not a loopback the display it
if ipnet, ok := address.(*net.IPNet); ok && ipnet.IP.IsGlobalUnicast() {
// cannot use slices.Contains for net.IP
for _, eip := range exclude {
if eip.Equal(ipnet.IP) {
// ip should be excluded skip to next one
continue outer
}
}
if IsIPv4(ipnet.IP) {
return ipnet.IP.String()
}
// if ipv6 we keep looking for an ipv4 address
ip = ipnet.IP.String()
}
}
return ip
}
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