gnunet-go: GNUnet implementation in Go

Copyright (C) 2019-2022 Bernd Fix >Y<

gnunet-go is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

gnunet-go is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see http://www.gnu.org/licenses/.

SPDX-License-Identifier: AGPL3.0-or-later

Caveat

THIS IS WORK-IN-PROGRESS AT A VERY EARLY STATE. DON'T EXPECT ANY COMPLETE DOCUMENTATION OR COMPILABLE, RUNNABLE OR EVEN OPERATIONAL SOURCE CODE.

TL;DR

Go v1.18+ is required to compile the code.

git clone https://github.com/bfix/gnunet-go
cd gnunet-go/src/gnunet
go mod tidy
go generate ./...
go install ./...
go test ./...

The binaries are stored in ${GOPATH}/bin.

Source code

All source code is written for Go v1.18+.

3rd party libraries are managed by the Go module framework. After downloading the source code, make sure you run go mod tidy in the src/gnunet folder to install all dependencies.

./src/gnunet

The folder src/gnunet contains a Go implementation of GNUnet: It is WIP and only provides a very limited coverage of GNUnet. The goal is to have a complete, functionally equivalent implementation of the GNUnet protocol in Go. Currently only some aspects of Transport, GNS, Revocation, Namecache and DHT are implemented.

Use ./build.sh withgen to build the executables (services and utilities, see below). The resulting programs are stored in ${GOPATH}/bin.

The withgen argument is optional (only needed if GANA registry files have changed and been updated in this repository by the user). The go generate step requires the stringer tool to be available; you can install it by running go install golang.org/x/tools/cmd/stringer@latest.

To run the unit tests, use ./test.sh.

./src/gnunet/enums

Changes in GANA definitions for block types, GNS record types and signature purpose values can be imported by copying the recfiles (GNU recutils) from GANA into this folder:

• gnunet-dht.rec
• gnunet-gns.rec
• gnunet-signature.rec

After updating the recfiles, you need to run go generate ./... to generate the new source files.

./src/gnunet/cmd

gnunet-service-dht-test-go: Implementation of the DHT core service (testbed).

gnunet-service-gns-go: Implementation of the GNS core service.

Stand-alone GNS service that could be used with other GNUnet utilities and services.

gnunet-service-revocation-go: Implementation of the GNS revocation service.

Stand-alone Revocation service that could be used with other GNUnet utilities and services.

revoke-zonekey: Implementation of a stand-alone program to calculate revocations.

This program creates a zone key revocation block. Depending on the parameters the calculation can take days or even weeks. The program can be interrupted at any time using ^C; restarting the program with the exact same parameters continues the calculation.

The following command-line options are available:

• -b: Number of leading zero bits (difficulty, default: 24). The minimum difficulty D is fixed at 23. The expiration of a revocation is derived using (b-D+1)*(1.1*EPOCH), where EPOCH is 365 days and it is extended by 10% in order to deal with unsynchronized clocks.

The default difficulty will create a revocation valid for ~2 years.

• -z: Zone key to be revoked (zone ID)

• -f: Name of file to store revocation data

• -t: testing mode: allow small difficulties for test runs.

• -v: verbose output

peer_mockup: test message exchange on the lowest level (transport).

vanityid: Compute GNUnet vanity peer id for a given regexp pattern.

N.B.: Key generation is slow at the moment, so be patient! To generate a single matching key some 1,000,000 keys need to be generated for a four letter prefix; this can take more than 30 minutes on average (depending on your CPU).

$ vanityid "^TST[0-9]"

Keys matching the pattern are printed to the console in the following format:

<vanity_id> [<hex.seed>][<hex.scalar>] (<count> tries, <time> elapsed)

The value of count tells how many key had been generated before a match was found; time is the time needed to find a match.

To generate the key files, make sure GNUnet is not running and do:

echo "<hex.seed>" | xxd -r -p > /var/lib/gnunet/.local/share/gnunet/private_key.ecc
chown gnunet:gnunet /var/lib/gnunet/.local/share/gnunet/private_key.ecc
chmod 600 /var/lib/gnunet/.local/share/gnunet/private_key.ecc

For gnunet-go configuration files you need to paste the result of echo "<hex.seed>" | xxd -r -p | base64 into the PrivateSeed field in the NodeConfig section.

Testing gnunet-go

To test the current gnunet-go implementation in a local GNUnet environment, you should follow the detailed instructions below.

N.B.: Testing requires an up-to-date GNUnet build from source. You can either use your local machine (please follow the GNUnet documentation for setup) or you can simply use a Docker image like gnunet-docker for this.

Testing R5N DHT

gnunet-go implements the DHT protocol specified in lsd0004 and uses a custom (unencrypted) transport protocol not supported by the standard GNUnet. Luckily there is a testbed in GNUnet that allows to run the new protocol over UDP/IP.

Starting the DHTU testbed

Make sure you stopped (or have not started) all GNUnet services; the testbed will take care of everything required.

Change into ./src/dht in the gnunet-Repository and start any number of DHTU nodes for testing:

./dhtu_testbed_deploy.sh 10

will start ten DHTU nodes. Nodes will listen to all available network addresses on port 10000+ (one node, one port).

Log and configuration files can be found in /tmp/deployment/; they are named by index (starting at 0).

Running the gnunet-go node in the testbed

Setting up the configuration file

Copy the example gnunet-config.json to dhtu-config.json and modify the network and local sections to our local setup. In this example 172.17.0.5 is the network address for GNUnet DHTU nodes and 172.17.0.1 is the network address for gnunet-go:

{
    "network": {
        "bootstrap": [
            "ip+udp://127.17.0.5:10000"
        ],
        "numPeers": 10
    },
    "local": {
        "privateSeed": "YGoe6XFH3XdvFRl+agx9gIzPTvxA229WFdkazEMdcOs=",
        "endpoints": [
            {
                "id": "r5n",
                "network": "ip+udp",
                "address": "172.17.0.1",
                "port": 2086,
                "ttl": 86400
            }
        ]
    }
    :
}

The above configuration will expect a network of 10 nodes and has a single bootstrap node (the first DHTU node in the testbed). gnunet-go will listen on port 2086.

Check the configuration for path definitions (especially /var/libg/gnunet/...) and make sure the folders exist and have R/W permissions for the user running the test.

Running the gnunet-gonode

Run the following commands to start the gnunet-go node:

rm -f /tmp/gnunet-system-runtime/*-go.sock
${GOPATH}/bin/gnunet-service-dht-go -c dhtu-config.json 2>&1 | tee run.log

Testing GNS

N.B.: The GNS service is currently not up-to-date. To test it, you need to check out version v0.1.23 (the latest tested version) and a matching GNUnet version as well (latest as of May 2020) to be on a safe side. You also need to have (all) GNUnet services up and running.

Setting up a modified configuration for GNUnet

You need to tell the GNUnet client which GNS service to use (either the default or the gnunet-go version) by modifying the GNS service socket. Copy your configuration file to gns-go.comf and modify the [gns] sectiom:

UNIXPATH = $GNUNET_RUNTIME_DIR/gnunet-service-gns-go.sock

This will ensure that clients (and other services) talk to the gnunet-go GNS service.

Setting up the configuration file (gnunet-go)

Copy the example gnunet-config.json to gns-config.json and modify the network and local sections:

{
    "network": {
        "bootstrap": [],
        "numPeers": 10
    },
    "local": {
        "privateSeed": "YGoe6XFH3XdvFRl+agx9gIzPTvxA229WFdkazEMdcOs=",
        "endpoints": []
    },
    :
}

Preparing and running the tests

For test purposes you need to start the gnunet-go DNS service, generate zones and resource records for testing and run the actual test cases. You can use the follwing script to do it all in one go:

#!/bin/bash

GNS_SOCK=/tmp/gnunet-system-runtime/gnunet-service-gns-go.sock
[ -e ${GNS_SOCK} ] && sudo rm -f ${GNS_SOCK}
sudo -u gnunet ../bin/gnunet-service-gns-go -L 5 &
GOGNS=$!

function get_pkey() {
    gnunet-identity -d -e $1 | sed 's/.* - //'
}

CERT=$(openssl x509 -in <(openssl s_client -connect gnunet.org:443 </dev/null 2>/dev/null) -outform der \
    | od -t x1 -A n \
    | tr "\n" " " \
    | sed "s/ //g")
VPN="ZH7W4PR933913VA45AH45GH9QNQVP3TEM89J18549Q6RNDV75A4G secret"


for x in zone9 private; do
    gnunet-identity -D $x
done

  gnunet-identity -C zone9
  gnunet-identity -C private

  gnunet-namestore -a -z zone9   -n "@"  -t NICK    -V "zone9"                  -e never
  gnunet-namestore -a -z zone9   -n web  -t A       -V 131.159.74.67            -e never
  gnunet-namestore -a -z zone9   -n web  -t BOX     -V "6 443 52 3 0 0 ${CERT}" -e never
  gnunet-namestore -a -z zone9   -n gn   -t CNAME   -V gnunet.org               -e never
  gnunet-namestore -a -z zone9   -n sec  -t VPN     -V "6 ${VPN}"               -e never
  gnunet-namestore -a -z zone9   -n prv  -t PKEY    -V "$(get_pkey private)"    -e never
# gnunet-namestore -a -z zone9   -n prv  -t A       -V "14.15.16.17"            -e never
  gnunet-namestore -a -z zone9   -n old  -t LEHO    -V "old.gnunet.org"         -e never
  gnunet-namestore -a -z zone9   -n old  -t A       -V 5.6.7.8                  -e never
# gnunet-namestore -a -z zone9   -n old  -t A       -V 10.11.12.13              -e never
# gnunet-namestore -a -z zone9   -n old  -t TXT     -V "Old version"            -e never

  gnunet-namestore -a -z private -n "@"  -t NICK    -V "nexus9"                 -e never
  gnunet-namestore -a -z private -n name -t TXT     -V "GNUnet test"            -e never
  gnunet-namestore -d -z private -n host
  gnunet-namestore -a -z private -n host -t GNS2DNS -V "[email protected]"     -e never
# gnunet-namestore -a -z private -n host -t A       -V 1.2.3.4                  -e never

function test_gns() {
    echo "========================"
    echo -n "Testing '$2' for type '$1': "
    gnunet-gns -t $1 -u $2 > plain.out
    gnunet-gns -c gns-go.conf -t $1 -u $2 > go.out
    rc=$(diff plain.out go.out)
    if [ -z "$rc" ]; then
        echo "O.K."
    else
        echo "FAILED!"
        echo "---------------- GNS-C"
        cat plain.out
        echo "---------------- GNS-Go"
        cat go.out
    fi
}

# (1)
test_gns any  web.zone9
# (2)
test_gns any  _443._tcp.web.zone9
# (3)
test_gns nick zone9
# (4)
test_gns any  gn.zone9
# (5)
test_gns any  sec.zone9
# (6)
test_gns pkey prv.zone9
# (7)
test_gns nick prv.zone9
# (8)
test_gns any  name.prv.zone9
# (9)
test_gns any  host.prv.zone9
# (10)
test_gns a  host.prv.zone9

kill ${GOGNS}

Using gnunet-go in your own projects

gnunet-go is not a standard Go module for direct use (via go.mod) in other packages, but designed as a stand-alone application. The rationale behind was to not hard link the code to a single Git provider.

If you are interested in using (parts of) gnunet-go in your own projects, the following step-by-step instructions show the easiest route.

• git clone https://github.com/bfix/gnunet-go into folder /home/user/gnunet-go (or any other folder if you adjust the instructions accordingly).

• create project folder and change into it

• run go mod init test (replace test with the name of your project)

• create a simple test main.go

package main

import (
    "crypto/rand"
    "fmt"
    "gnunet/util"
)

func main() {
    a := make([]byte, 32)
    rand.Read(a)
    fmt.Println(util.EncodeBinaryToString(a))
}

• edit go.mod and add at end of file:

require gnunet v0.1.34

replace gnunet v0.1.34 => /home/user/gnunet-go/src/gnunet

• run go mod tidy
• build test program: go build
• run test program: ./test

The only disadvantage of this approach is that you have to update the source code for gnunet-go yourself. From time to time or on demand, do a git pull followed by a go mod tidy described above. No version control is supported either because the dependency for gnunet-go is redirected to a local folder.