96 lines
2.3 KiB
Go
96 lines
2.3 KiB
Go
package util
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import (
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"net"
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)
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// IsIPv6 returns true if netIP is IPv6.
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func IsIPv6(netIP net.IP) bool {
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return netIP != nil && netIP.To4() == nil
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}
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// IsIPv4 returns true if netIP is IPv4.
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func IsIPv4(netIP net.IP) bool {
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return netIP != nil && netIP.To4() != nil
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}
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// LastIPInSubnet gets the last IP in a subnet
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func LastIPInSubnet(addr *net.IPNet) (net.IP, error) { //nolint:interfacer
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// re-parse to ensure clean network address
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_, cidr, err := net.ParseCIDR(addr.String())
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if err != nil {
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return nil, err
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}
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ones, bits := cidr.Mask.Size()
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if ones == bits {
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return cidr.IP, nil
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}
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for i := range cidr.IP {
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cidr.IP[i] |= ^cidr.Mask[i]
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}
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return cidr.IP, nil
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}
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// FirstIPInSubnet gets the first IP in a subnet
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func FirstIPInSubnet(addr *net.IPNet) (net.IP, error) { //nolint:interfacer
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// re-parse to ensure clean network address
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_, cidr, err := net.ParseCIDR(addr.String())
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if err != nil {
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return nil, err
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}
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ones, bits := cidr.Mask.Size()
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if ones == bits {
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return cidr.IP, nil
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}
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cidr.IP[len(cidr.IP)-1]++
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return cidr.IP, nil
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}
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// NormalizeIP will transform the given ip to the 4 byte len ipv4 if possible
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func NormalizeIP(ip *net.IP) {
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ipv4 := ip.To4()
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if ipv4 != nil {
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*ip = ipv4
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}
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}
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// GetLocalIP returns the first non loopback local IPv4 of the host.
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// If no ipv4 address is found it may return an ipv6 address.
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// When no ip is found and empty string is returned.
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func GetLocalIP() string {
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return GetLocalIPExcluding(nil)
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}
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// GetLocalIPExcluding returns the first non loopback local IPv4 of the host.
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// If no ipv4 address is found it may return an ipv6 address.
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// Additionally you can specify a list of ips that should not be returned.
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// When no ip is found and empty string is returned.
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func GetLocalIPExcluding(exclude []net.IP) string {
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addrs, err := net.InterfaceAddrs()
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if err != nil {
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return ""
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}
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ip := ""
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outer:
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for _, address := range addrs {
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// check the address type and if it is not a loopback the display it
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if ipnet, ok := address.(*net.IPNet); ok && ipnet.IP.IsGlobalUnicast() {
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// cannot use slices.Contains for net.IP
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for _, eip := range exclude {
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if eip.Equal(ipnet.IP) {
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// ip should be excluded skip to next one
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continue outer
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}
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}
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if IsIPv4(ipnet.IP) {
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return ipnet.IP.String()
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}
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// if ipv6 we keep looking for an ipv4 address
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ip = ipnet.IP.String()
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}
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}
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return ip
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}
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