97 lines
2.5 KiB
Go
97 lines
2.5 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 utils
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import (
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"net"
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"strings"
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)
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// IPString returns a simple IP string from the given net.Addr.
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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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//TODO(dan): Why is this needed, does this happen?
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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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// AddrLookupHostname returns the hostname (if possible) or address for the given `net.Addr`.
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func AddrLookupHostname(addr net.Addr) string {
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if AddrIsUnix(addr) {
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return "localhost"
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}
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return LookupHostname(IPString(addr))
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}
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// AddrIsLocal returns whether the address is from a trusted local connection (loopback or unix).
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func AddrIsLocal(addr net.Addr) bool {
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if tcpaddr, ok := addr.(*net.TCPAddr); ok {
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return tcpaddr.IP.IsLoopback()
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}
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_, ok := addr.(*net.UnixAddr)
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return ok
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}
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// AddrToIP returns the IP address for a net.Addr, or nil if it's a unix domain socket.
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func AddrToIP(addr net.Addr) net.IP {
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if tcpaddr, ok := addr.(*net.TCPAddr); ok {
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return tcpaddr.IP
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}
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return nil
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}
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// AddrIsUnix returns whether the address is a unix domain socket.
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func AddrIsUnix(addr net.Addr) bool {
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_, ok := addr.(*net.UnixAddr)
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return ok
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}
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// LookupHostname returns the hostname for `addr` if it has one. Otherwise, just returns `addr`.
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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) > 0 {
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candidate := strings.TrimSuffix(names[0], ".")
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if IsHostname(candidate) {
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return candidate
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}
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}
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// return original address if no hostname found
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if len(addr) > 0 && addr[0] == ':' {
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// fix for IPv6 hostnames (so they don't start with a colon), same as all other IRCds
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addr = "0" + addr
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}
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return addr
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}
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var allowedHostnameChars = "abcdefghijklmnopqrstuvwxyz1234567890-."
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// IsHostname returns whether we consider `name` a valid hostname.
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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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