54 lines
1,004 B
Go
54 lines
1,004 B
Go
// Copyright 2015 The Chihaya Authors. All rights reserved.
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// Use of this source code is governed by the BSD 2-Clause license,
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// which can be found in the LICENSE file.
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package udp
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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)
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var connectionKey, connectionIV []byte
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func InitConnectionIDEncryption() error {
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connectionKey = make([]byte, 16)
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_, err := rand.Read(connectionKey)
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if err != nil {
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return err
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}
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connectionIV = make([]byte, 16)
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_, err = rand.Read(connectionIV)
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return err
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}
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func GenerateConnectionID(ip []byte) []byte {
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block, err := aes.NewCipher(connectionKey)
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if err != nil {
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panic(err)
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}
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if len(ip) > 16 {
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panic("IP larger than 16 bytes")
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}
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for len(ip) < 8 {
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ip = append(ip, ip...) // Not enough bits in output.
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}
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ct := make([]byte, 16)
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stream := cipher.NewCFBDecrypter(block, connectionIV)
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stream.XORKeyStream(ct, ip)
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for i := len(ip) - 1; i >= 8; i-- {
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ct[i-8] ^= ct[i]
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}
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return ct[:8]
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}
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func init() {
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InitConnectionIDEncryption()
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}
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