mirror of
https://github.com/cbeuw/Cloak.git
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72 lines
2.1 KiB
Go
72 lines
2.1 KiB
Go
package util
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import (
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"encoding/binary"
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//xxhash "github.com/OneOfOne/xxhash"
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mux "github.com/cbeuw/Cloak/internal/multiplex"
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)
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// For each frame, the three parts of the header is xored with three keys.
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// The keys are generated from the SID and the payload of the frame.
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// FIXME: this code will panic if len(data)<18.
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func genXorKeys(secret []byte, data []byte) (i uint32, ii uint32, iii uint32) {
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/*
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h := xxhash.New32()
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ret := make([]uint32, 3)
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preHash := make([]byte, 16)
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for j := 0; j < 3; j++ {
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copy(preHash[0:10], secret[j*10:j*10+10])
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copy(preHash[10:16], data[j*6:j*6+6])
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h.Write(preHash)
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ret[j] = h.Sum32()
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}
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return ret[0], ret[1], ret[2]
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*/
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return 0, 0, 0
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}
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func MakeObfs(key []byte) func(*mux.Frame) []byte {
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obfs := func(f *mux.Frame) []byte {
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obfsedHeader := make([]byte, 12)
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// header: [StreamID 4 bytes][Seq 4 bytes][Closing 4 bytes]
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i, ii, iii := genXorKeys(key, f.Payload[0:18])
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binary.BigEndian.PutUint32(obfsedHeader[0:4], f.StreamID^i)
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binary.BigEndian.PutUint32(obfsedHeader[4:8], f.Seq^ii)
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binary.BigEndian.PutUint32(obfsedHeader[8:12], f.Closing^iii)
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// Composing final obfsed message
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// We don't use util.AddRecordLayer here to avoid unnecessary malloc
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obfsed := make([]byte, 5+12+len(f.Payload))
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obfsed[0] = 0x17
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obfsed[1] = 0x03
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obfsed[2] = 0x03
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binary.BigEndian.PutUint16(obfsed[3:5], uint16(12+len(f.Payload)))
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copy(obfsed[5:17], obfsedHeader)
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copy(obfsed[17:], f.Payload)
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// obfsed: [record layer 5 bytes][cipherheader 12 bytes][payload]
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return obfsed
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}
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return obfs
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}
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func MakeDeobfs(key []byte) func([]byte) *mux.Frame {
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deobfs := func(in []byte) *mux.Frame {
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peeled := in[5:]
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i, ii, iii := genXorKeys(key, peeled[12:30])
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streamID := binary.BigEndian.Uint32(peeled[0:4]) ^ i
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seq := binary.BigEndian.Uint32(peeled[4:8]) ^ ii
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closing := binary.BigEndian.Uint32(peeled[8:12]) ^ iii
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payload := make([]byte, len(peeled)-12)
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copy(payload, peeled[12:])
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ret := &mux.Frame{
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StreamID: streamID,
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Seq: seq,
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Closing: closing,
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Payload: payload,
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}
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return ret
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}
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return deobfs
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}
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