63 lines
1.5 KiB
Go
63 lines
1.5 KiB
Go
|
package aghnet
|
||
|
|
|
||
|
|
import (
|
||
|
|
"net"
|
||
|
|
"strconv"
|
||
|
|
)
|
||
|
|
|
||
|
|
// The maximum lengths of generated hostnames for different IP versions.
|
||
|
|
const (
|
||
|
|
ipv4HostnameMaxLen = len("192-168-100-100")
|
||
|
|
ipv6HostnameMaxLen = len("ff80-f076-0000-0000-0000-0000-0000-0010")
|
||
|
|
)
|
||
|
|
|
||
|
|
// generateIPv4Hostname generates the hostname for specific IP version.
|
||
|
|
func generateIPv4Hostname(ipv4 net.IP) (hostname string) {
|
||
|
|
hnData := make([]byte, 0, ipv4HostnameMaxLen)
|
||
|
|
for i, part := range ipv4 {
|
||
|
|
if i > 0 {
|
||
|
|
hnData = append(hnData, '-')
|
||
|
|
}
|
||
|
|
hnData = strconv.AppendUint(hnData, uint64(part), 10)
|
||
|
|
}
|
||
|
|
|
||
|
|
return string(hnData)
|
||
|
|
}
|
||
|
|
|
||
|
|
// generateIPv6Hostname generates the hostname for specific IP version.
|
||
|
|
func generateIPv6Hostname(ipv6 net.IP) (hostname string) {
|
||
|
|
hnData := make([]byte, 0, ipv6HostnameMaxLen)
|
||
|
|
for i, partsNum := 0, net.IPv6len/2; i < partsNum; i++ {
|
||
|
|
if i > 0 {
|
||
|
|
hnData = append(hnData, '-')
|
||
|
|
}
|
||
|
|
for _, val := range ipv6[i*2 : i*2+2] {
|
||
|
|
if val < 10 {
|
||
|
|
hnData = append(hnData, '0')
|
||
|
|
}
|
||
|
|
hnData = strconv.AppendUint(hnData, uint64(val), 16)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return string(hnData)
|
||
|
|
}
|
||
|
|
|
||
|
|
// GenerateHostname generates the hostname from ip. In case of using IPv4 the
|
||
|
|
// result should be like:
|
||
|
|
//
|
||
|
|
// 192-168-10-1
|
||
|
|
//
|
||
|
|
// In case of using IPv6, the result is like:
|
||
|
|
//
|
||
|
|
// ff80-f076-0000-0000-0000-0000-0000-0010
|
||
|
|
//
|
||
|
|
func GenerateHostname(ip net.IP) (hostname string) {
|
||
|
|
if ipv4 := ip.To4(); ipv4 != nil {
|
||
|
|
return generateIPv4Hostname(ipv4)
|
||
|
|
} else if ipv6 := ip.To16(); ipv6 != nil {
|
||
|
|
return generateIPv6Hostname(ipv6)
|
||
|
|
}
|
||
|
|
|
||
|
|
return ""
|
||
|
|
}
|