118 lines
3.4 KiB
Markdown
118 lines
3.4 KiB
Markdown
# tunnel-packer
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| Sponsored by [ppl](https://ppl.family) |
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A strategy for packing and unpacking tunneled network messages (or any stream) in node.js
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Examples
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```js
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var Packer = require('tunnel-packer');
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Packer.create({
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onmessage: function (msg) {
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// msg = { family, address, port, service, data };
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}
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, onend: function (msg) {
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// msg = { family, address, port };
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}
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, onerror: function (err) {
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// err = { message, family, address, port };
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}
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});
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var chunk = Packer.pack(address, data, service);
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var addr = Packer.socketToAddr(socket);
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var id = Packer.addrToId(address);
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var id = Packer.socketToId(socket);
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var myDuplex = Packer.Stream.create(socketOrStream);
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var myTransform = Packer.Transform.create({
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address: {
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family: '...'
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, address: '...'
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, port: '...'
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}
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// hint at the service to be used
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, service: 'https'
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});
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```
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# Testing an implementation
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If you want to write a compatible packer, just make sure that for any given input
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you get the same output as the packer does.
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```bash
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node test-pack.js input.json output.bin
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hexdump output.bin
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```
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Where `input.json` looks something like this:
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`input.json`:
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```
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{ "version": 1
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, "address": {
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"family": "IPv4"
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, "address": "127.0.1.1"
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, "port": 443
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, "service": "foo"
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}
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, "filepath": "./sni.tcp.bin"
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}
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```
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Raw TCP SNI Packet
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------------------
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and `sni.tcp.bin` is any captured tcp packet, such as this one with a tls hello:
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`sni.tcp.bin`:
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```
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0 1 2 3 4 5 6 7 8 9 A B C D D F
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0000000 16 03 01 00 c2 01 00 00 be 03 03 57 e3 76 50 66
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0000010 03 df 99 76 24 c8 31 e6 e8 08 34 6b b4 7b bb 2c
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0000020 f3 17 aa 5c ec 09 da da 83 5a b2 00 00 56 00 ff
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0000030 c0 24 c0 23 c0 0a c0 09 c0 08 c0 28 c0 27 c0 14
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0000040 c0 13 c0 12 c0 26 c0 25 c0 05 c0 04 c0 03 c0 2a
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0000050 c0 29 c0 0f c0 0e c0 0d 00 6b 00 67 00 39 00 33
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0000060 00 16 00 3d 00 3c 00 35 00 2f 00 0a c0 07 c0 11
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0000070 c0 02 c0 0c 00 05 00 04 00 af 00 ae 00 8d 00 8c
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0000080 00 8a 00 8b 01 00 00 3f 00 00 00 19 00 17 00 00
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0000090 14 70 6f 6b 65 6d 61 70 2e 68 65 6c 6c 61 62 69
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00000a0 74 2e 63 6f 6d 00 0a 00 08 00 06 00 17 00 18 00
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00000b0 19 00 0b 00 02 01 00 00 0d 00 0c 00 0a 05 01 04
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00000c0 01 02 01 04 03 02 03
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00000c7
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```
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Tunneled TCP SNI Packet
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-----------------------
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You should see that the result is simply all of the original packet with a leading header.
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Note that `16 03 01 00` starts at the 29th byte (at index 28 or 0x1C) instead of at index 0:
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```
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0 1 2 3 4 5 6 7 8 9 A B C D D F
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0000000 fe 1a 49 50 76 34 2c 31 32 37 2e 30 2e 31 2e 31 <-- 0xfe = v1, 0x1a = 26 more bytes for header
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0000010 2c 34 34 33 2c 31 39 39 2c 66 6f 6f
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16 03 01 00 <-- first 4 bytes of tcp packet
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0000020 c2 01 00 00 be 03 03 57 e3 76 50 66 03 df 99 76
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0000030 24 c8 31 e6 e8 08 34 6b b4 7b bb 2c f3 17 aa 5c
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0000040 ec 09 da da 83 5a b2 00 00 56 00 ff c0 24 c0 23
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0000050 c0 0a c0 09 c0 08 c0 28 c0 27 c0 14 c0 13 c0 12
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0000060 c0 26 c0 25 c0 05 c0 04 c0 03 c0 2a c0 29 c0 0f
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0000070 c0 0e c0 0d 00 6b 00 67 00 39 00 33 00 16 00 3d
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0000080 00 3c 00 35 00 2f 00 0a c0 07 c0 11 c0 02 c0 0c
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0000090 00 05 00 04 00 af 00 ae 00 8d 00 8c 00 8a 00 8b
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00000a0 01 00 00 3f 00 00 00 19 00 17 00 00 14 70 6f 6b
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00000b0 65 6d 61 70 2e 68 65 6c 6c 61 62 69 74 2e 63 6f
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00000c0 6d 00 0a 00 08 00 06 00 17 00 18 00 19 00 0b 00
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00000d0 02 01 00 00 0d 00 0c 00 0a 05 01 04 01 02 01 04
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00000e0 03 02 03
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00000e3
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```
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