Cannot encode onion address

[ricott1]

When I try to call multiaddress() on a onion address like /onion/3g2upl4pq6kufc4m I get an error in codec.bufferToTuples:
Error: Error parsing address: Invalid address buffer: bc03

Any idea how to solve this? Are onion addresses already implemented?

[jacobheun]

The code has been added to the protocol table but convert.js likely needs to be updated to handle the conversion. Adding some tests for various onion addresses and fixing the conversion code where needed would be the best path forward. Happy to review a PR if you'd be up for submitting one! :)

[ricott1]

Hi Jacob, thanks for the feedback. I changed the convert.js file to handle the onion and onion3 cases using the str2buf(str) function, but I really don't know if this is correct. I'm still getting an error: in bufferToTuples the size of the address that you get from
let size = sizeForAddr(p, buf.slice(i + n))
is not correct. I suppose I'm doing something wrong, but I'm kinda lost now.

[jacobheun]

I'm not very familiar with onion addresses but looking at the go implementation there will need to be more in depth parsing of the string than just using str2buf. You can look at how go is doing the onion and onion3 transcoding, https://github.com/multiformats/go-multiaddr/blob/0460aad0fe51f7aa64d3a3c17854dc25368f7ca2/transcoders.go#L128-L213. The string needs to be split by : to determine the port.

It would also be good to leverage the same bad and good onion addresses from the go test suite when testing here.

[ricott1]

Ok, I added the following to converter.js:

const base32 = require('hi-base32')
function onion2buf(str) {
    const addr = str.split(':')
    if (addr.length !== 2) {
        throw new Error('failed to parse onion addr: ' + addr + ' does not contain a port number')
    }
    if (addr[0].length !== 16) {
        throw new Error('failed to parse onion addr: ' + addr[0] + ' not a Tor onion address.')
    }
    const buf = Buffer.from(base32.decode.asBytes(addr[0].toUpperCase()))
    const size = Buffer.from(varint.encode(buf.length))
    //onion port number
    
    const port = parseInt(addr[1], 10);
    
    if (port < 1 || port > 65536) {
        throw new Error("Port number is not in range(1, 65536)")
    }
    const portBuf = port2buf(port)
    return Buffer.concat([buf, portBuf])
}

I checked it against the python implementation and it gives the same result. I still have to understand your code 100%, but I think the general direction is correct. I'll finish up with the onion3 protocol and submit a pull in the next days.

[jacobheun]

Released in 6.1.0