68 lines
1.8 KiB
Go
68 lines
1.8 KiB
Go
// Copyright (c) 2012-2014 Jeremy Latt
|
|
// Copyright (c) 2016 Daniel Oaks <daniel@danieloaks.net>
|
|
// released under the MIT license
|
|
|
|
package irc
|
|
|
|
import (
|
|
"net"
|
|
"strings"
|
|
)
|
|
|
|
// IPString returns a simple IP string from the given net.Addr.
|
|
func IPString(addr net.Addr) string {
|
|
addrStr := addr.String()
|
|
ipaddr, _, err := net.SplitHostPort(addrStr)
|
|
//TODO(dan): Why is this needed, does this happen?
|
|
if err != nil {
|
|
return addrStr
|
|
}
|
|
return ipaddr
|
|
}
|
|
|
|
// AddrLookupHostname returns the hostname (if possible) or address for the given `net.Addr`.
|
|
func AddrLookupHostname(addr net.Addr) string {
|
|
return LookupHostname(IPString(addr))
|
|
}
|
|
|
|
// LookupHostname returns the hostname for `addr` if it has one. Otherwise, just returns `addr`.
|
|
func LookupHostname(addr string) string {
|
|
names, err := net.LookupAddr(addr)
|
|
if err != nil || len(names) < 1 || !IsHostname(names[0]) {
|
|
// return original address if no hostname found
|
|
if len(addr) > 0 && addr[0] == ':' {
|
|
// fix for IPv6 hostnames (so they don't start with a colon), same as all other IRCds
|
|
addr = "0" + addr
|
|
}
|
|
return addr
|
|
}
|
|
|
|
return names[0]
|
|
}
|
|
|
|
var allowedHostnameChars = "abcdefghijklmnopqrstuvwxyz1234567890-."
|
|
|
|
// IsHostname returns whether we consider `name` a valid hostname.
|
|
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
|
|
}
|