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net.go
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net.go
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// Copyright (c) 2012-2014 Jeremy Latt
// Copyright (c) 2016- Daniel Oaks <daniel@danieloaks.net>
// released under the MIT license
package irc
import (
"net"
"strings"
)
func IPString(addr net.Addr) Name {
addrStr := addr.String()
ipaddr, _, err := net.SplitHostPort(addrStr)
if err != nil {
return Name(addrStr)
}
return Name(ipaddr)
}
func AddrLookupHostname(addr net.Addr) Name {
return LookupHostname(IPString(addr))
}
func LookupHostname(addr Name) Name {
names, err := net.LookupAddr(addr.String())
if err != nil {
return Name(addr)
}
hostname := strings.TrimSuffix(names[0], ".")
return Name(hostname)
}
var allowedHostnameChars = "abcdefghijklmnopqrstuvwxyz1234567890-."
func IsHostname(name string) bool {
// IRC hostnames specifically require a period
if !strings.Contains(name, ".") || len(name) < 1 || len(name) > 253 {
return false
}
// ensure each part of hostname is valid
for _, part := range strings.Split(name, ".") {
if len(part) < 1 || len(part) > 63 || strings.HasPrefix(part, "-") || strings.HasSuffix(part, "-") {
return false
}
}
// ensure all chars of hostname are valid
for _, char := range strings.Split(strings.ToLower(name), "") {
if !strings.Contains(allowedHostnameChars, char) {
return false
}
}
return true
}