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