64 lines
1.8 KiB
Go
64 lines
1.8 KiB
Go
// Copyright 2016, Cong Ding. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Author: Cong Ding <dinggnu@gmail.com>
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package stun
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import (
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"net"
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)
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// Padding the length of the byte slice to multiple of 4.
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func padding(bytes []byte) []byte {
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length := uint16(len(bytes))
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return append(bytes, make([]byte, align(length)-length)...)
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}
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// Align the uint16 number to the smallest multiple of 4, which is larger than
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// or equal to the uint16 number.
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func align(n uint16) uint16 {
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return (n + 3) & 0xfffc
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}
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// isLocalAddress check if localRemote is a local address.
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func isLocalAddress(local, localRemote string) bool {
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// Resolve the IP returned by the STUN server first.
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localRemoteAddr, err := net.ResolveUDPAddr("udp", localRemote)
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if err != nil {
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return false
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}
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// Try comparing with the local address on the socket first, but only if
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// it's actually specified.
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addr, err := net.ResolveUDPAddr("udp", local)
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if err == nil && addr.IP != nil && !addr.IP.IsUnspecified() {
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return addr.IP.Equal(localRemoteAddr.IP)
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}
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// Fallback to checking IPs of all interfaces
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addrs, err := net.InterfaceAddrs()
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if err != nil {
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return false
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}
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for _, addr := range addrs {
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ip, _, err := net.ParseCIDR(addr.String())
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if err != nil {
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continue
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}
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if ip.Equal(localRemoteAddr.IP) {
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return true
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}
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}
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return false
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}
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