go-gittisane

A soft-fork of gitea with support for running as an I2P service. Just the mod and the CI files.

How it works:

This uses GitHub CI to continuously build an I2P-only version of Gitea based on the latest release of Gitea. We can do this without requiring a patch to the Gitea source code. This is because Gitea encapsulates its "Listening" and "Dialing" into functions, which can easily be substituted for alternative versions. For instance, the network listener is set up by a function, graceful.GetListener() (net.Listener, error) in the file modules/graceful/server.go. The default implementation of the GetListener() (net.Listener, error) function, DefaultGetListener() (net.Listener, error) is defined in the modules/graceful/net_unix.go for Unix-like systems and modules/graceful/net_windows.go for Windows-like systems. A developer who wishes to "Mod" gitea to listen on another kind of connection do so by creating a new file which implements a GetListener() (net.Listener, error) function using an alternate listener implementation.

On the client side, the same thing is possible because Go allows you to substitute the underlying transports used for the default HTTP Client. So, in the absence of overriding settings, we can configure it to use SAMv3 to build HTTP connections by default using the same keys as the hidden service. Effectively this is like a "Bidirectional HTTP" tunnel in Java's Hidden Service Manager.

Finally, if you need to include additional libraries, run go mod tidy in the root of the gitea checkout to include them.

Here is a complete working example mod:

// copy this file to modules/graceful/net_anon.go before building gitea
package graceful

import (
	"net"
	"net/http"

	"github.com/go-i2p/onramp"
)

// First, make sure that the onramp.Garlic API is set up:
var garlic, i2perr = onramp.NewGarlic("gitea-anon", "127.0.0.1:7656", onramp.OPT_DEFAULTS)

// This implements the GetListener function for I2P. Note the exemption for Unix sockets, which is implemented in net_anon_unix.go and net_anon_windows.go
func I2PGetListener(network, address string) (net.Listener, error) {
	// Add a deferral to say that we've tried to grab a listener
	defer GetManager().InformCleanup()
	switch network {
	case "tcp", "tcp4", "tcp6", "i2p", "i2pt":
		return garlic.Listen()
	case "unix", "unixpacket":
		// I2P isn't really a replacement for the stuff you use Unix sockets for and it's also not an anonymity risk, so treat them normally
		unixAddr, err := net.ResolveUnixAddr(network, address)
		if err != nil {
			return nil, err
		}
		return GetListenerUnix(network, unixAddr)
	default:
		return nil, net.UnknownNetworkError(network)
	}
}

// We use `init() to ensure that the I2P Listeners and Dialers are correctly placed at runtime`
func init() {
	if i2perr != nil {
		panic(i2perr)
	}
	GetListener = I2PGetListener
	httpClient := &http.Client{
		Transport: &http.Transport{
			Dial: garlic.Dial,
		},
	}

	http.DefaultClient = httpClient
	http.DefaultTransport = httpClient.Transport
}

Caveats

Gitea makes a few other kinds of connections, besides HTTP, if instructed to do so in the config file. For instance, there is an SMTP client. This is not anonymized in this configuration. Probably ask Postman if it's OK to use 127.0.0.1:7659/7660. Similarly, SSH client connections are not anonymized in this configuration. Similar adjustments to the configuration can be made to also route these across I2P but aren't documented here at this time.

License

Both this mod and gitea are licensed under the MIT license. See LICENSE for net_anon*.go in this repository. LICENSE-gitea.md is a copy of the Gitea license from https://github.com/go-gitea/gitea