About

This chapter contains background information for the library. We give a general introduction to eduVPN and explain what problems this library aims to solve.

EduVPN introduction

eduVPN-common is a library for eduVPN, which is a VPN by SURF and a project by GÉANT, for research institutes and universities. Each institute that uses eduVPN has its own server. To discover these servers and establish a VPN connection with them, eduVPN clients are used. eduVPN has clients for each common platform:

The problem

However, as these clients are rather similar in functionality, apart from platform specific differences, right now there is duplicate code between them. For example, the process to discover institution's servers, the authorization process (OAuth) and Wireguard key generation. This goal of this library is to provide the common functionality between these clients into one codebase. The library is written in the Go language and aims to have wrapper code for each of the languages that are used by the current clients.

The main goal is thus the following:

This library tries to remove non-platform specific common functionality. This way eduVPN clients have less duplicate code. The building blocks that are removed by the library is not just the four depicted in this figure. You can think of other building blocks, such as logging and local configuration file saving. As can be seen in the figure, no User Interface (UI) code will be implemented. This is left to the eduVPN clients, on top of platform-specific code.

License

MIT

Authors

This library is written by Steven Wallis de Vries and Jeroen Wijenbergh at the SURF and GÉANT organization.

Getting started

This chapter contains the steps to get started with the Go library and the Python wrapper. You will learn how to build the library/wrapper, how to run the test suite and how to debug possible errors.

Note that the Python wrapper is currently the only wrapper. So for now, we only document the Python wrapper in this documentation and in the future document the other wrappers as well.

The documentation on how to use this library in your own code will be given in the next chapter: API.

Building

This section contains the instruction on how to build the library and associated wrappers. We first explain how to build the Go library and then further explain the wrapper specific building process. As the Python wrapper is the only wrapper at the moment, this only consists of this wrapper language for now.

Building the Go library

To build the Go library, you need the dependencies for your system installed. We will go over the needed dependencies for Linux. Afterwards, we explain the basic commands to build the library.

Dependencies

Linux

To build the Go shared library using Linux you need the following dependencies:

Go 1.18 or later
Gcc
GNU Make
Dependencies for the Python wrapper if you want to build that as well

Commands

Before we can begin building the wrapper code, we need to build the Go code as a shared library. This section will tell you how to do so.

To build the shared library for the current platform issue the following command in the root directory:

make

The shared library will be output in lib/.

Cleaning

To clean build the library and wrapper, issue the following command in the root directory:

make clean

Note on releases

Releases are build with the go tag "release" (add flag "-tags=release") to bundle the discovery JSON files and embed them in the shared library. See the make_release script on how we bundle the files. A full command without the Makefile to build this library is:

go build -o lib/libeduvpn_common-${VERSION}.so -tags=release -buildmode=c-shared ./exports

Python wrapper

To build the python wrapper issue the following command (in the root directory of the eduvpn-common project):

make -C wrappers/python

This uses the makefile in wrappers/python/Makefile to build the python file into a wheel placed in wrappers/python/dist/eduvpncommon-[version]-py3-none-[platform].whl. Where version is the version of the library and platform is your current platform.

The wheel can be installed with pip:

pip install ./wrappers/python/dist/eduvpncommon-[version]-py3-none-[platform].whl

Example: commands to build for Python

This section gives an example on how to build and install the library from scratch (assuming you have all the dependencies). It builds the Go library and then builds and installs the Python wrapper.

Clone the library

git clone https://github.com/eduvpn/eduvpn-common

Go to the library directory

cd eduvpn-common

Build the go library

make

Build the python wrapper

make -C wrappers/python

Install the wheel using pip

# x.x.x is the version here
pip install wrappers/python/dist/eduvpncommon-x.x.x-py3-none-linux_x86_64.whl

Note that the name of your wheel changes on the platform and version.

Package formats

We support the following additional package formats: RPM (Linux, Fedora) and Deb (Linux, Debian derivatives)

Linux: RPM

The RPM files can be found on a SourceHut Repo.These are then build with builder.rpm.

Linux: Deb

The RPM files can be found on a SourceHut Repo. These are then build with nbuilder.deb.

Building for release

To build for release, make sure you obtain the tarball artifacts in the release (ending with .tar.xz) at https://github.com/eduvpn/eduvpn-common/releases.

These are signed with minisign and gpg keys, make sure to verify these signatures using the public keys available here: https://github.com/eduvpn/eduvpn-common/tree/main/keys, they are also available externally:

To build for release, make sure to extract the tarball, and then add -tags=release to the GOFLAGS environment variable:

GOFLAGS="-tags=release" make

Proceed the build like normally.

Testing

The Go library right now has various tests defined. E.g. server interaction, oauth, discovery and signature verification tests.

To run the Go test suite, issue the following command in a shell

make test

Note that this runs the tests without any server interaction (so for now only the signature verification tests). To run the tests with an eduVPN server you need to specify environment variables:

SERVER_URI="eduvpn.example.com" PORTAL_USER="example" PORTAL_PASS="example" make test

This needs python3-selenium and geckodriver (extract and put in your $PATH). Note that testing with a server assumes it uses a default portal, due to it needing to click on buttons on the web page. You can add your own portal by customizing the called Selenium script.

If you have Docker installed and Docker-compose you can use a convenient helper script which starts up two containers

An eduVPN server for testing
A Go container that builds and runs the test-suite

PORTAL_USER="example" PORTAL_PASS="example" ./ci/startcompose.sh

Note that this helper script also assumes you have the OpenSSL command line tool installed. This is used to install the self-signed certificates for testing.

This script is also used in the continuous integration, so we recommend to run this before you submit any changes.

There are other environment variables that can be used:

OAUTH_EXPIRED_TTL: Use this for a server which has a low OAuth access token expiry time, e.g. 10 seconds. You would then set this variable to "10" so that a test is ran which waits for 10 seconds for the OAuth tokens to expire
EDUVPN_PODCOMP: Set this to 1 to instruct the ./ci/startcompose.sh script to use podman-compose if you prefer this over using docker-compose.

Testing the Python code

To test the Python code, issue the following command in a shell (you will need dependencies for all wrappers if you do this¹):

make -C wrappers/python test

API

This chapter is an introduction to the eduvpn-common API. It is meant as a high-level overview on how to use API and build your own eduVPN/Let's Connect! client. In this chapter, we go over the basics of how the interop between Go and language x works, say something about the architecture, explain where to find detailed API documentation, explain the state machine, give a typical flow for a client and give a follow along tutorial on building an eduVPN client using Python code. At last, we will also have a few code examples that can be used as a short reference.

Go <-> language X interop

Because this library is meant to be a general library for other clients to use that are written in different programming languages, we need to find a way to make this Go library available on each platform and codebase. The approach that we take is to build a C library from the Go library using Cgo. Cgo can have its disadvantages with performance and the constant conversion between Go and C types. To overcome those barriers, this library has the following goals (with some others noted here):

Be high-level. Functions should do as much as possible in Go. The exported API should fit in one file. Lots of low-level functions would be a constant conversion between C and Go which adds overhead
Move as much state to Go as possible. For example, Go keeps track of the servers you have configured and discovery. This makes the arguments to functions simple, clients should pass simple identifiers that Go can look up in the state
Easy type conversion: to convert between C and Go types, JSON is used. Whereas Protobuf, Cap'n'proto or flatbuffers are more performant, they are harder to debug, add thousands of lines of autogenerated code and are not human friendly. Using JSON, the clients can approach it the same way they would use with a server using a REST API. Another approach is to just convert from Go -> C types -> language types. This was tried in version 1 of the library, but this ended up being too much work and manual memory management
Make it as easy as possible for clients to manage UI and internal state: we use a state machine that gives the clients information in which state the Go library is in, e.g. we're selecting a server profile, we're loading the server endpoints. This library is not only a layer to talk to eduVPN servers, but the whole engine for a client
Implement features currently not present in existing clients: WireGuard to OpenVPN failover, WireGuard over TCP
Follow the official eduVPN specification and also contribute changes when needed
Secure: We aim to follow the latest OAuth recommendations, to not store secret data and e.g. disable OpenVPN scripts from being ran by default

And finally the most important goal:

The advantages that this library brings for clients should outweigh the cost of incorporating it into the codebase. Initial versions would take more work than we get out of it. However, when each eduVPN/Let's Connect! client uses this library we should expect a net gain. New features should be easier to implement for clients by simply requiring a new eduvpn-common version and using the necessary functions

Architecture

In the previous section, we have already hinted a bit on the exact architecture. This section will expand upon it by giving a figure of the basic structure

graph TD;
A[Go]-- Compiles to -->B[C shared library .so/.dll];
C[Language wrapper]-- Loads -->B
Client -- Uses --> C;

As can be seen by this architecture, there is an intermediate layer between the client and the shared library. This wrapper eases the way of loading this library and then defining a more language specific API for it. In the eduvpn-common repo, we currently only support a Python wrapper. Clients themselves can define their own wrapper

Typical flow for a client

NOTE: This uses the function names that are defined in the exports file in Go. For your own wrapper/the Python wrapper they are different. But the general flow is the same

The client starts up. It calls the Register function that communicates with the library that it has initialized
It gets the list of servers using ServerList
When the user selects a server to connect to in the UI, it calls the GetConfig to get a VPN configuration for this server. This function transitions the state machine multiple times. The client uses these state transitions for logging or even updating the UI. The client then connects
- New feature in eduvpn-common: Check if the VPN can reach the gateway after the client is connected by calling StartFailover
If the client has no servers, or it wants to add a new server, the client calls DiscoOrganizations and DiscoServers to get the discovery files from the library. This even returns cached copies if the organizations or servers should not have been updated according to the documentation
- From this discovery list, it calls AddServer to add the server to the internal server list of eduvpn-common. This also calls necessary state transitions, e.g. for authorizing the server. The next call to ServerList then has this server included
- It can then get a configuration for this server like we have explained in step 3
When a configuration has been obtained, the internal state has changed and the client can get the current server that was configured using CurrentServer. CurrentServer can also be called after startup if a server was previously set as the current server.
When the VPN disconnects, the client calls Cleanup so that the server resources are cleaned up by calling the /disconnect endpoint
A server can be removed with the RemoveServer function
When the client is done, it calls Deregister such that the most up to date internal state is saved to disk. Note that eduvpn-common also saves the internal state .e.g. after obtaining a VPN configuration

Where to find API docs

The API documentation, depends on which wrapper you are using. If you're writing a wrapper yourself, or want some background information on how it works internally, you can find function docs in the exports/exports.go file it is available as autogenerated form here.

This file is commented using Go comment style. It gives a basic of what the function does, what it returns and what type of arguments you should pass to it. The API documentation for the Python wrapper can be found here.

There is also a Go API that is defined in the client package. However, this is not the primary use case for the library.

Finite state machine

The eduvpn-common library uses a finite state machine internally to keep track of which state the client is in and to communicate data callbacks (e.g. to communicate the Authorization URL in the OAuth process to the client).

Viewing the FSM

To view the FSM in an image, register to the library with in debug mode. This outputs the graph with a .graph extension in the client-specified config directory. The format of this graph is from Mermaid. You can convert this to an image using the Mermaid command-line client installed or from the Mermaid web site, the Mermaid Live Editor

FSM example

The following is an example of the FSM when the client has obtained a Wireguard/OpenVPN configuration from an eduVPN server

graph TD

style Deregistered fill:cyan
Deregistered(Deregistered) -->|Register| Main

style Main fill:white
Main(Main) -->|Deregister| Deregistered

style Main fill:white
Main(Main) -->|Add a server| AddingServer

style Main fill:white
Main(Main) -->|Get a VPN config| GettingConfig

style Main fill:white
Main(Main) -->|Already connected| Connected

style AddingServer fill:white
AddingServer(AddingServer) -->|Authorize| OAuthStarted

style OAuthStarted fill:white
OAuthStarted(OAuthStarted) -->|Authorized| Main

style GettingConfig fill:white
GettingConfig(GettingConfig) -->|Invalid location| AskLocation

style GettingConfig fill:white
GettingConfig(GettingConfig) -->|Invalid or no profile| AskProfile

style GettingConfig fill:white
GettingConfig(GettingConfig) -->|Successfully got a configuration| GotConfig

style GettingConfig fill:white
GettingConfig(GettingConfig) -->|Authorize| OAuthStarted

style AskLocation fill:white
AskLocation(AskLocation) -->|Location chosen| GettingConfig

style AskProfile fill:white
AskProfile(AskProfile) -->|Profile chosen| GettingConfig

style GotConfig fill:white
GotConfig(GotConfig) -->|Get a VPN config again| GettingConfig

style GotConfig fill:white
GotConfig(GotConfig) -->|VPN is connecting| Connecting

style Connecting fill:white
Connecting(Connecting) -->|VPN is connected| Connected

style Connecting fill:white
Connecting(Connecting) -->|Cancel connecting| Disconnecting

style Connected fill:white
Connected(Connected) -->|VPN is disconnecting| Disconnecting

style Disconnecting fill:white
Disconnecting(Disconnecting) -->|VPN is disconnected| Disconnected

style Disconnecting fill:white
Disconnecting(Disconnecting) -->|Cancel disconnecting| Connected

style Disconnected fill:white
Disconnected(Disconnected) -->|Connect again| GettingConfig

style Disconnected fill:white
Disconnected(Disconnected) -->|Renew| OAuthStarted

The current state is highlighted in the cyan color.

State explanation

For the explanation of what all the different states mean, see the client documentation

States that ask data

In eduvpn-common, there are certain states that require attention from the client.

OAuth Started: A state that must be handled by the client. How a client can 'handle' this state, we will see in the next section. In this state, the client must open the webbrowser with the authorization URL to complete to OAuth process. Note that on mobile platforms, you also need to reply with the authorization URI as these platforms do not support a local callback server using 127.0.0.1
Ask Profile: The state that asks for a profile selection to the client. Reply to this state by using a "cookie" and the CookieReply function. What this means will be discussed in the Python client example too
Ask Location: Same for ask profile but for selecting a secure internet location. Only called if one must be chosen, e.g. due to a selection that is no longer valid

The rest of the states are miscellaneous states, meaning that the client can handle them however it wants to. However, it can be useful to handle most state transitions to e.g. show loading screens or for logging and debugging purposes.

Let's build a client using Python

To begin, let's follow the flow and see if we can figure out how it works.

Registering

The client starts up. It calls the Register function that communicates with the library that it has initialized

In Python, this works like the following:

First import the library

import eduvpn_common.main as edu

class Transitions:
    def __init__(self, common):
        self.common = common

# These arguments can be found in the docstring
# But also in the exports.go file
# For Python it's a bit different, we have split the arguments into the constructor and register
# Here we pass the client ID for OAuth, the version of the client and the directory where config files should be found
common=edu.EduVPN("org.eduvpn.app.linux", "0.0.1", "/tmp/test")

common.register(debug=True)

# we will come back to this later
transitions = Transitions(common)
common.register_class_callbacks(transitions)

Now after registering, we know that we have no servers configured (unless you're following this tutorial again with an existing /tmp/test). So we continue with step 4

Discovery

If the client has no servers, or it wants to add a new server, the client calls DiscoOrganizations and DiscoServers to get the discovery files from the library.

# Let's get them and print them
print(common.get_disco_organizations())
print(common.get_disco_servers())

We get a big JSON blob, so which format is this? From the Go documentation:

DiscoOrganizations gets the organizations from discovery, returned as types/discovery/discovery.go Organizations marshalled as JSON

DiscoServers gets the servers from discovery, returned as types/discovery/discovery.go Servers marshalled as JSON

If you follow these files, you see two structs, Servers and Organizations. These structs have json tags associated with them. You can use this structure to figure out how to parse the returned data. In case of discovery, it's very similar to the JSON files from the discovery server.

Adding a server

The next bullet point that we implement is the following:

From this discovery list, it calls AddServer to add the server to the internal server list of eduvpn-common. This also calls necessary state transitions, e.g. for authorizing the server. The next call to ServerList then has this server included

The discovery servers contains a server called the demo server. Let's try to add it. To add it we need to pass the type of server we're adding. From discovery we can deduce that this is an institute access server as the JSON looks like the following:

{
    "authentication_url_template": "",
    "base_url": "https://demo.eduvpn.nl/",
    "display_name": {
        "en": "Demo"
    },
    "server_type": "institute_access", # this is why we know it is Institute Access
    "support_contact": [
        "mailto:eduvpn@surf.nl"
    ]
},

From the Go documentation, we know that the identifier must be the Base URL:

id is the identifier of the string

In case of secure internet: The organization ID

In case of custom server: The base URL

In case of institute access: The base URL

# Compare this to the Go version, the non-interactive field is optional here as it is default False
common.add_server(edu.ServerType.INSTITUTE_ACCESS, "https://demo.eduvpn.nl/")

But we get an error!

eduvpn_common.main.WrappedError: fsm failed transition from 'Chosen_Server' to 'OAuth_Started', is this required transition handled?

This is the state machine we briefly mentioned before. Some functions require that you handle certain transitions. From the Go documentation, we can find this in the documentation as well that you must handle this transition. Let's handle it in Python to open the webbrowser for the OAuth process.

We do this with the python wrapper by defining a class of state transitions. This class was already added and registered with register_class_callbacks. However, there was no transition added. Let's add it

import webbrowser
from eduvpn_common.event import class_state_transition
from eduvpn_common.state import State, StateType

class Transitions:
    def __init__(self, common):
        self.common = common

    @class_state_transition(State.OAUTH_STARTED, StateType.ENTER)
    def enter_oauth(self, old_state: State, url: str):
        webbrowser.open(url)

Now if you re-rerun the whole code with this transition added, your webbrowser should open.

Note that this state transition is essentially the same as the following code:

-def handler(old: int, new: int, data: str):
-    # it's 6 because https://github.com/eduvpn/eduvpn-common/blob/b660911b5db000b43970f3754b5767bb50741360/client/fsm.go#L33
-    if new == 6:
-        webbrowser.open(data)
-        return True
-    return False

This is the code that is passed to the Go library. It handles certain states and returns False (zero) if a state is not handled, True (non-zero) if it is. If you define your own wrapper you should build an abstraction layer that resolves to a handler similar as above. This handler should be passed as a C function to the Go library when registering.

After you have authorized the application through the portal using the webbrowser, the server should have been added:

print(common.get_servers())

Returns:

{
  "institute_access_servers": [
    {
      "display_name": {
        "en": "Demo"
      },
      "identifier": "https://demo.eduvpn.nl/",
      "profiles": {
        "current": ""
      },
      "delisted": false
    }
  ]
}

The format of this JSON is specified in the Go documentation:

(in exports/exports.go)

It returns the server list as a JSON string defined in types/server/server.go List

Obtaining a VPN configuration from the server

The next part of the flow is:

When the user selects a server to connect to in the UI, it calls the GetConfig to get a VPN configuration for this server. This function transitions the state machine multiple times. The client uses these state transitions for logging or even updating the UI. The client then connects

Let's try it, the required arguments are the same for adding a config in the Python wrapper:

print(common.get_config(edu.ServerType.INSTITUTE_ACCESS, "https://demo.eduvpn.nl"))

However, this gives an exception:

eduvpn_common.main.WrappedError: fsm failed transition from 'Request_Config' to 'Ask_Profile', is this required transition handled?

A similar error to the OAuth error we had before. This Ask_Profile transition is there for the client/user to choose a profile as this server has multiple profiles defined.

To handle this transition and thus choose a profile to continue, we must do multiple steps:

Add the condition to the transitions class
Parse the data that we get back
Reply with a choice for the profile

If we add the condition and print the data:

@class_state_transition(State.ASK_PROFILE, StateType.ENTER)
def enter_ask_profile(self, old_state: State, data: str):
    print("profiles:", data)

we get back the following JSON (from the Go docs: The data for this transition is defined in types/server/server.go RequiredAskTransition with embedded data Profiles in types/server/server.go):

{
  "cookie": 4,
  "data": {
    "map": {
      "internet": {
        "display_name": {
          "en": "Internet"
        },
        "supported_protocols": [
          1,
          2
        ]
      },
      "internet-split": {
        "display_name": {
          "en": "No rfc1918 routes"
        },
        "supported_protocols": [
          1,
          2
        ]
      }
    },
    "current": ""
  }
}

This thus gives you the list of profiles with a so-called "cookie". This cookie is used to confirm the choice to the Go library. To do so we must do the following to handle this:

import json

# Do this inside the Transitions class
@class_state_transition(State.ASK_PROFILE, StateType.ENTER)
def enter_ask_profile(self, old_state: State, data: str):
    # parse the json
    json_dict = json.loads(data)
    
    self.common.cookie_reply(json_dict["cookie"], "internet")

If we then re-run the code, we get back the following JSON (from the Go docs: The return data is the configuration, marshalled as JSON and defined in types/server/server.go Configuration)

{
  "config": "the WireGuard config",
  "protocol": 2, # 2 specifies WireGuard
  "default_gateway": true
}

Cleanup

The flow also mentioned:

When the client is done, it calls Deregister such that the most up to date internal state is saved to disk. Note that eduvpn-common also saves the internal state .e.g. after obtaining a VPN configuration

Let's be a nice client and do this:

common.deregister()

If we then call any function, we get an error, so it is important that you do this on exit:

print(common.get_servers())
>>> eduvpn_common.main.WrappedError: No state available, did you register the client?

But when we register again and then get the list of servers, the servers are retrieved from disk:

common=edu.EduVPN("org.eduvpn.app.linux", "0.0.1", "/tmp/test")
common.register(debug=True)
print(common.get_servers())

gives

{
  "institute_access_servers": [
    {
      "display_name": {
        "en": "Demo"
      },
      "identifier": "https://demo.eduvpn.nl/",
      "profiles": {
        "map": {
          "internet": {
            "display_name": {
              "en": "Internet"
            },
            "supported_protocols": [
              1,
              2
            ]
          },
          "internet-split": {
            "display_name": {
              "en": "No rfc1918 routes"
            },
            "supported_protocols": [
              1,
              2
            ]
          }
        },
        "current": "internet"
      },
      "delisted": false
    }
  ]
}

Note the difference with the previous JSON, the profiles are now initialized because we have gotten a configuration before.

If the /tmp/test directory is removed (the argument that was passed to register), we get no servers again:

import shutil
shutil.rmtree("/tmp/test")
common=edu.EduVPN("org.eduvpn.app.linux", "0.0.1", "/tmp/test")
common.register(debug=True)
print(common.get_servers())

gives "{}", an empty JSON object string

Code examples

This chapter contains code examples that use the API

Go command line client

The following is an example in the repository. It is a command line client with the following flags

  -get-custom string
        The url of a custom server to connect to
  -get-institute string
        The url of an institute to connect to
  -get-secure string
        Gets secure internet servers

// Package main implements an example CLI client
package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"reflect"
	"strings"

	"github.com/eduvpn/eduvpn-common/client"
	"github.com/eduvpn/eduvpn-common/internal/version"
	"github.com/eduvpn/eduvpn-common/types/cookie"
	srvtypes "github.com/eduvpn/eduvpn-common/types/server"

	"github.com/pkg/browser"
)

// Open a browser with xdg-open.
func openBrowser(data interface{}) {
	str, ok := data.(string)
	if !ok {
		return
	}
	fmt.Printf("OAuth: Authorization URL: %s\n", str)
	fmt.Println("Opening browser...")
	go func() {
		err := browser.OpenURL(str)
		if err != nil {
			fmt.Fprintln(os.Stderr, "failed to open browser with error:", err)
			fmt.Println("Please open your browser manually")
		}
	}()
}

// GetLanguageMatched uses a map from language tags to strings to extract the right language given the tag
// It implements it according to https://github.com/eduvpn/documentation/blob/dc4d53c47dd7a69e95d6650eec408e16eaa814a2/SERVER_DISCOVERY.md#language-matching
func GetLanguageMatched(langMap map[string]string, langTag string) string {
	// If no map is given, return the empty string
	if len(langMap) == 0 {
		return ""
	}
	// Try to find the exact match
	if val, ok := langMap[langTag]; ok {
		return val
	}
	// Try to find a key that starts with the OS language setting
	for k := range langMap {
		if strings.HasPrefix(k, langTag) {
			return langMap[k]
		}
	}
	// Try to find a key that starts with the first part of the OS language (e.g. de-)
	pts := strings.Split(langTag, "-")
	// We have a "-"
	if len(pts) > 1 {
		for k := range langMap {
			if strings.HasPrefix(k, pts[0]+"-") {
				return langMap[k]
			}
		}
	}
	// search for just the language (e.g. de)
	for k := range langMap {
		if k == pts[0] {
			return langMap[k]
		}
	}

	// Pick one that is deemed best, e.g. en-US or en, but note that not all languages are always available!
	// We force an entry that is english exactly or with an english prefix
	for k := range langMap {
		if k == "en" || strings.HasPrefix(k, "en-") {
			return langMap[k]
		}
	}

	// Otherwise just return one
	for k := range langMap {
		return langMap[k]
	}

	return ""
}

// Ask for a profile in the command line.
func sendProfile(state *client.Client, data interface{}) {
	fmt.Printf("Multiple VPN profiles found. Please select a profile by entering e.g. 1")
	d, ok := data.(*srvtypes.RequiredAskTransition)
	if !ok {
		fmt.Fprintf(os.Stderr, "\ninvalid data type: %v\n", reflect.TypeOf(data))
		return
	}
	sps, ok := d.Data.(*srvtypes.Profiles)
	if !ok {
		fmt.Fprintf(os.Stderr, "\ninvalid data type for profiles: %v\n", reflect.TypeOf(d.Data))
		return
	}

	ps := ""
	var options []string
	i := 0
	for k, v := range sps.Map {
		ps += fmt.Sprintf("\n%d - %s", i+1, GetLanguageMatched(v.DisplayName, "en"))
		options = append(options, k)
		i++
	}

	// Show the profiles
	fmt.Println(ps)

	var idx int
	if _, err := fmt.Scanf("%d", &idx); err != nil || idx <= 0 ||
		idx > len(sps.Map) {
		fmt.Fprintln(os.Stderr, "invalid profile chosen, please retry")
		sendProfile(state, data)
		return
	}

	p := options[idx-1]
	fmt.Println("Sending profile ID", p)
	if err := d.C.Send(p); err != nil {
		fmt.Fprintln(os.Stderr, "failed setting profile with error", err)
	}
}

// The callback function
// If OAuth is started we open the browser with the Auth URL
// If we ask for a profile, we send the profile using command line input
// Note that this has an additional argument, the vpn state which was wrapped into this callback function below.
func stateCallback(state *client.Client, _ client.FSMStateID, newState client.FSMStateID, data interface{}) {
	if newState == client.StateOAuthStarted {
		openBrowser(data)
	}

	if newState == client.StateAskProfile {
		sendProfile(state, data)
	}
}

// Get a config for Institute Access or Secure Internet Server.
func getConfig(state *client.Client, url string, srvType srvtypes.Type) (*srvtypes.Configuration, error) {
	if !strings.HasPrefix(url, "http") {
		url = "https://" + url
	}
	ck := cookie.NewWithContext(context.Background())
	defer ck.Cancel() //nolint:errcheck
	err := state.AddServer(ck, url, srvType, nil)
	if err != nil {
		return nil, err
	}
	return state.GetConfig(ck, url, srvType, false, false)
}

// Get a config for a single server, Institute Access or Secure Internet.
func printConfig(url string, srvType srvtypes.Type) {
	var c *client.Client
	c, err := client.New(
		"org.eduvpn.app.linux",
		fmt.Sprintf("%s-cli", version.Version),
		"configs",
		func(old client.FSMStateID, new client.FSMStateID, data interface{}) bool {
			stateCallback(c, old, new, data)
			return true
		},
		true,
	)
	if err != nil {
		fmt.Printf("Register error: %v", err)
		return
	}
	_ = c.Register()

	ck := cookie.NewWithContext(context.Background())
	_, err = c.DiscoOrganizations(ck, "")
	if err != nil {
		panic(err)
	}
	_, err = c.DiscoServers(ck, "")
	if err != nil {
		panic(err)
	}

	defer c.Deregister()

	cfg, err := getConfig(c, url, srvType)
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed getting a config: %v\n", err)
		return
	}
	fmt.Println(cfg.Protocol)
	fmt.Println("Obtained config:", cfg.VPNConfig)
}

// The main function
// It parses the arguments and executes the correct functions.
func main() {
	cu := flag.String("get-custom", "", "The url of a custom server to connect to")
	u := flag.String("get-institute", "", "The url of an institute to connect to")
	sec := flag.String("get-secure", "", "Gets secure internet servers")
	flag.Parse()

	// Connect to a VPN by getting an Institute Access config
	switch {
	case *cu != "":
		printConfig(*cu, srvtypes.TypeCustom)
	case *u != "":
		printConfig(*u, srvtypes.TypeInstituteAccess)
	case *sec != "":
		printConfig(*sec, srvtypes.TypeSecureInternet)
	default:
		flag.PrintDefaults()
	}
}

This document was automatically generated from the exports/exports.go file

About the API

package main implements the main exported API to be used by other languages

Some notes:

Errors are returned as JSON c strings. The JSON type is defined in types/error/error.go Error. Free them using FreeString. Same is the case for other string types, you should also free them. The errors are always localized
Types are converted from the Go representation to C using JSON strings
Cookies are used for cancellation, just fancy contexts. Create a cookie using CookieNew, pass it to the function that needs one as the first argument. To cancel the function, call CookieCancel, passing in the same cookie as argument
Cookies must also be freed, by using the CookieDelete function if the cookie is no longer needed
The state machine is used to track the state of a client. It is mainly used for asking for certain data from the client, e.g. asking for profiles and locations. But a client may also wish to build upon this state machine to build the whole UI around it. The SetState and InState functions are useful for this

Functions

AddServer

Signature:

func AddServer(c C.uintptr_t, _type C.int, id *C.char, ot *C.longlong) *C.char

AddServer adds a server to the eduvpn-common server list c is the cookie that is used for cancellation. Create a cookie first with CookieNew. This same cookie is also used for replying to state transitions.

_type is the type of server that needs to be added. This type is defined in types/server/server.go Type

id is the identifier of the string:

In case of secure internet: The organization ID
In case of custom server: The base URL
In case of institute access: The base URL

ni stands for non-interactive. If non-zero, any state transitions will not be run.

This ot flag is useful for preprovisioned servers; set this to non-null to non-interactively add a server. This flag represents the Unix time OAuth was last triggered, if the server needs to be added non-interactively but there is no token structure, set this to zero (integer) or the current Unix time. This value will be overwritten once OAuth is triggered.

If the server cannot be added it returns the error as types/error/error.go Error. Note that the server is removed when an error has occured

The following state callbacks are mandatory to handle:

OAUTH_STARTED: This indicates that the OAuth procedure has been started, it returns the URL as the data. The client should open the webbrowser with this URL and continue the authorization process. Note: For mobile platforms this returns a Cookie and data (json: {"cookie": x, "data": url}). This url should also be opened in the browser like desktop platforms. But these platforms also need to reply to the library to give back the full authorization code URI with CookieReply(x, uri). E.g. CookieReply(x, "/callback?code=...&state=...&iss=...") this is the path of the request that the apps get back when the user clicks approve. For this, apps need to register an app url or sorts. For the valid values for app URLs, see the redirect URIs for mobile platforms here https://git.sr.ht/~fkooman/vpn-user-portal/tree/v3/item/src/OAuth/VpnClientDb.php

Example Input (3=custom server): AddServer(mycookie, 3, "https://demo.eduvpn.nl", 0)

Example Output:

{
  "message": {
    "en": "failed to add server"
  },
  "misc": false
}

CalculateGateway

Signature:

func CalculateGateway(subnet *C.char) (*C.char, *C.char)

CalculateGateway calculates the gateway for a subnet, it can take IPv4 or IPv6 networks with CIDR notation as inputs and returns the gateway address.

This is useful to pass to StartFailover. It returns an error if it fails to calculate a gateway. The function is implemented according to: the eduVPN docs.

Example Input: CalculateGateway("10.10.0.5/24")

Example Output: "10.10.0.1", null

Cleanup

Signature:

func Cleanup(c C.uintptr_t) *C.char

Cleanup sends a /disconnect to cleanup the connection. Additionally, if ProxyGuard is active it cancels the running process

This MUST be called when disconnecting, see the eduVPN docs. c is the Cookie that needs to be passed. Create a new Cookie using CookieNew.

If it was unsuccessful, it returns an error.

Example Input: Cleanup(myCookie)

Example Output:

{
  "message": {
    "en": "cleanup was not successful"
  },
  "misc": false
}

CookieCancel

Signature:

func CookieCancel(c C.uintptr_t) *C.char

CookieCancel cancels the cookie.

This means that functions which take this as first argument, return if they're still running. The error cause is always context.Canceled for that cancelled function: see the Go docs.

This CookieCancel function can also return an error if cancelling was unsuccessful. Example Input: CookieCancel(myCookie)

Example Output: null

CookieDelete

Signature:

func CookieDelete(c C.uintptr_t) *C.char

CookieDelete deletes the cookie by cancelling it and deleting the underlying cgo handle.

This function MUST be called when the cookie that is created using CookieNew is no longer needed. Example Input: CookieDelete(myCookie)

Example Output: null

CookieNew

Signature:

func CookieNew() C.uintptr_t

CookieNew creates a new cookie and returns it.

This value should not be parsed or converted somehow by the client. This value is simply to pass back to the Go library. This value has two purposes:

Cancel a long running function
Send a reply to a state transition (ASK_PROFILE and ASK_LOCATION)

Example Input: CookieNew()

Example Output: 5

CookieReply

Signature:

func CookieReply(c C.uintptr_t, data *C.char) *C.char

CookieReply replies to a state transition using the cookie.

c is the Cookie
data is the data to send, e.g. a profile ID

Example Input: CookieReply(myCookie, "split-tunnel-profile")

Example Output: null

CurrentServer

Signature:

func CurrentServer() (*C.char, *C.char)

CurrentServer gets the current server from eduvpn-common

In eduvpn-common, a server is marked as 'current' if you have gotten a VPN configuration for it

It returns the server as JSON, defined in types/server/server.go Current.

If there is no current server or some other, e.g. there is no current state, an error is returned with a nil string.

Example Input: CurrentServer()

Example Output:

{
  "institute_access_server": {
    "display_name": {
      "en": "Demo"
    },
    "identifier": "https://demo.eduvpn.nl/",
    "profiles": {
      "map": {
        "internet": {
          "display_name": {
            "en": "Internet"
          },
          "supported_protocols": [
            1,
            2
          ]
        },
        "internet-split": {
          "display_name": {
            "en": "No rfc1918 routes"
          },
          "supported_protocols": [
            1,
            2
          ]
        }
      },
      "current": "internet"
    },
    "support_contacts": [
      "mailto:eduvpn@surf.nl"
    ],
    "delisted": false
  },
  "server_type": 1
}, null

Deregister

Signature:

func Deregister() *C.char

Deregister cleans up the state for the client.

This function SHOULD be called when the application exits such that the configuration file is saved correctly. Note that saving of the configuration file also happens in other cases, such as after getting a VPN configuration. Thus it is often not problematic if this function cannot be called due to a client crash.

If no client is available or deregistering fails, it returns an error.

Example Input: Deregister()

Example Output:

{
  "message": {
    "en": "failed to deregister"
  },
  "misc": false
}

DiscoOrganizations

Signature:

func DiscoOrganizations(c C.uintptr_t, search *C.char) (*C.char, *C.char)

DiscoOrganizations gets the organizations from discovery, returned as types/discovery/discovery.go Organizations marshalled as JSON.

c is the Cookie that needs to be passed. Create a new Cookie using CookieNew
search is the search string for filtering the list.

If any of the words in the search query is not contained in any of the display names or keywords, the candidate is filtered. Otherwise they are ranked based on the levenshtein distance: Levenshtein Wikipedia. If search is empty it returns ALL organizations currently known in common

If it was unsuccessful, it returns an error. Note that when the lib was built in release mode the data is almost always non-nil, even when an error has occurred This means it has just returned the cached list, the error should then not be handled in a fatal way. E.g. show the returned cache list but log the error or show the error with a warning.

Example Input: DiscoOrganizations(myCookie, "")

Example Output:

{
 "organization_list": [
   {
     "display_name": {
       "en": "Academic Network of Albania - RASH"
     },
     "org_id": "https://idp.rash.al/simplesaml/saml2/idp/metadata.php",
   },
   {
     "display_name": {
       "da": "Dansk Sprognævn",
       "en": "Danish Language Council"
     },
     "org_id": "http://idp.dsn.dk/adfs/services/trust",
   },
   {
     "display_name": {
       "da": "Erhvervsakademi Aarhus",
       "en": "Business Academy Aarhus"
     },
     "org_id": "http://adfs.eaaa.dk/adfs/services/trust",
}, null

Example Input: DiscoOrganizations(myCookie, "rash")

Example Output:

	{
	 "organization_list": [
	   {
	     "display_name": {
	       "en": "Academic Network of Albania - RASH"
	     },
	     "org_id": "https://idp.rash.al/simplesaml/saml2/idp/metadata.php",
	   },
      ]
	}, null

DiscoServers

Signature:

func DiscoServers(c C.uintptr_t, search *C.char) (*C.char, *C.char)

DiscoServers gets the servers from discovery, returned as types/discovery/discovery.go Servers marshalled as JSON

c is the Cookie that needs to be passed. Create a new Cookie using CookieNew
search is the search string for filtering the list.

If any of the words in the search query is not contained in any of the display names or keywords, the candidate is filtered. Otherwise they are ranked based on the levenshtein distance: Levenshtein Wikipedia. If search is empty it returns ALL servers currently known in common

If it was unsuccessful, it returns an error. Note that when the lib was built in release mode the data is almost always non-nil, even when an error has occurred. This means it has just returned the cached list, the error should then not be handled in a fatal way. E.g. show the returned cache list but log the error or show the error with a warning.

Example Input: DiscoServers(myCookie, "")

Example Output:

	{
	 "server_list": [
	   {
	     "base_url": "https://eduvpn.rash.al/",
          "country_code": "AL",
	     "server_type": "secure_internet",
	   },
	   {
	     "base_url": "https://eduvpn.deic.dk/",
          "country_code": "DK",
	     "server_type": "secure_internet",
	} , null

Example Input: DiscoServers(myCookie, "heanet")

Example Output:

	{
	 "server_list": [
         {
           "base_url": "https://eduvpn.heanet.ie/",
           "display_name": {
             "en": "HEAnet Staff"
            },
           "server_type": "institute_access",
         },
       ]
	} , null

DiscoveryStartup

Signature:

func DiscoveryStartup(refresh C.RefreshList) *C.char

DiscoveryStartup does a discovery request in the background.

The refresh argument is a callback that is called when the refreshing is done.

When this callback is thus called, the app SHOULD refresh the server list of the already configured servers. This DiscoveryStartup function MUST be called after calling Register.

ExpiryTimes

Signature:

func ExpiryTimes() (*C.char, *C.char)

ExpiryTimes gets the expiry times for the current server

Expiry times are just fields that represent unix timestamps at which to do certain events regarding expiry, e.g. when to show the renew button, when to show expiry notifications

The expiry times structure is defined in types/server/server.go Expiry If some error occurs, it is returned as types/error/error.go Error

Example Input: ExpiryTimes()

Example Output (1...4 are unix timestamps):

{
     "start_time": 1,
     "end_time": 2,
     "button_time": 3,
     "countdown_time": 4,
     "notification_times": [
         1,
         2,
     ],
}, null

FreeString

Signature:

func FreeString(addr *C.char)

FreeString frees a string that was allocated by the eduvpn-common Go library.

This happens when we return strings, such as errors from the Go lib back to the client. The client MUST thus ensure that this memory is freed using this function. Simply pass the pointer to the string in here.

Example Input: FreeString(strPtr)

GetConfig

Signature:

func GetConfig(c C.uintptr_t, _type C.int, id *C.char, pTCP C.int, startup C.int) (*C.char, *C.char)

GetConfig gets a configuration for the server. It returns additional information in case WireGuard over Proxyguard is used (see the last example)

c is the cookie that is used for cancellation. Create a cookie first with CookieNew, this same cookie is also used for replying to state transitions

_type is the type of server that needs to be added. This type is defined in types/server/server.go Type

id is the identifier of the string

In case of secure internet: The organization ID
In case of custom server: The base URL
In case of institute access: The base URL

pTCP is if we prefer TCP or not to get the configuration, non-zero means yes

startup is if the client is just starting up, set this to true (non-zero) if you autoconnect to a server on startup. If this startup value is true (non-zero) then any authorization or other callacks (profile/location) are not triggered

After getting a configuration, the FSM moves to the GOT_CONFIG state The return data is the configuration, marshalled as JSON and defined in types/server/server.go Configuration

If the config cannot be retrieved it returns an error as types/error/error.go Error.

The current state callbacks MUST be handled:

ASK_PROFILE

This asks the client for profile.

This is called when the user/client has not set a profile for this server before, or the current profile is invalid

When the user has selected a profile, reply with the choice using the CookieReply function and the profile ID e.g. CookieReply(cookie, "wireguard"). CookieReply can be done in the background as the Go library waits for a reply

The data for this transition is defined in types/server/server.go RequiredAskTransition with embedded data Profiles in types/server/server.go. Note that RequiredAskTransition contains the cookie to be used for the CookieReply.

So a client would:

Parse the data to get the cookie and data
get the cookie
get the profiles from the data
show it in the UI and then reply with CookieReply using the choice

ASK_LOCATION

This asks the client for a location. Note that under normal circumstances, this callback is not actually called as the home organization for the secure internet server is set as the current if for some reason, an invalid location has been configured, the library will ask the client for a new one

When the user has selected a location, reply with the choice using the CookieReply function and the location ID e.g. CookieReply(cookie, "nl")

CookieReply can be done in the background as the Go library waits for a reply The data for this transition is defined in types/server/server.go RequiredAskTransition with embedded data a list of strings ([]string)

Note that RequiredAskTransition contains the cookie to be used for the CookieReply function,

So a client would:

Parse the data to get the cookie and data
get the cookie
get the list of locations from the data
show it in the UI and then reply with CookieReply using the choice

OAUTH_STARTED

OAUTH_STARTED: This indicates that the OAuth procedure has been started, it returns the URL as the data. The client should open the webbrowser with this URL and continue the authorization process. Note: For mobile platforms this returns a Cookie and data (json: {"cookie": x, "data": url}). This url should also be opened in the browser like desktop platforms. But these platforms also need to reply to the library to give back the full authorization code URI with CookieReply(x, uri). E.g. CookieReply(x, "/callback?code=...&state=...&iss=...") this is the path of the request that the apps get back when the user clicks approve. For this, apps need to register an app url or sorts. For the valid values for app URLs, see the redirect URIs for mobile platforms here https://git.sr.ht/~fkooman/vpn-user-portal/tree/v3/item/src/OAuth/VpnClientDb.php

The client should open the webbrowser with this URL and continue the authorization process. This is only called if authorization needs to be retriggered

Example Input (3=custom server): GetConfig(myCookie, 3, "https://demo.eduvpn.nl/", 0, 0)

Example Output (2=WireGuard):

{
 "config": "[Interface]\nPrivateKey = ...\nAddress = ...\nDNS = ...\n\n[Peer]\nPublicKey = ...=\nAllowedIPs = 0.0.0.0/0,::/0\nEndpoint = ...",
 "protocol": 2,
 "default_gateway": true,
 "should_failover": true, <- whether or not the failover procedure should happen
}

Example Output (3=WireGuard + Proxyguard):

{
"config":"[Interface]\nMTU = ...\nAddress = ...\nDNS = ...\nPrivateKey = ...\n[Peer]\nPublicKey = ...\nAllowedIPs = ...\nEndpoint = 127.0.0.1:x\n",
"protocol":3,
"default_gateway":true,
"should_failover":true,
"proxy":{"source_port":38683,"listen":"127.0.0.1:59812","peer":"https://..."}
}

InState

Signature:

func InState(fsmState C.int) (C.int, *C.char)

InState checks if the FSM is in fsmState.

Example Input: InState(5)

Example Output: 1, null

Register

Signature:

func Register(
   name *C.char,
   version *C.char,
   configDirectory *C.char,
   cb C.StateCB,
   debug C.int,
) *C.char

Name is the name of the client, must be a valid client ID.

Version is the version of the client. This version field is used for the user agent in all HTTP requests.

cb is the state callback. It takes three arguments: The old state, the new state and the data for the state as JSON.

Note that the states are defined in client/fsm.go, e.g. Main (in Go: StateMain), ASK_PROFILE (in Go: StateAskProfile)
This callback returns non-zero if the state transition is handled. This is used to check if the client handles the needed transitions

debug, if non-zero, enables debugging mode for the library, this means:

Log everything in debug mode, so you can get more detail of what is going on
Write the state graph to a file in the configDirectory. This can be used to create a FSM png file with mermaid https://mermaid.js.org/

After registering, the FSM is initialized and the state transition MAIN should have been completed If some error occurs during registering, it is returned as a types/error/error.go Error

Example Input: Register("org.eduvpn.app.linux", "0.0.1", "/tmp/eduvpn-common", myCallbackFunc, 1)

Example Output:

{
  "message": {
    "en": "failed to register, a VPN state is already present"
  },
  "misc": false
}

RemoveServer

Signature:

func RemoveServer(_type C.int, id *C.char) *C.char

RemoveServer removes a server from the eduvpn-common server list

_type is the type of server that needs to be added. This type is defined in types/server/server.go Type

id is the identifier of the string:

In case of secure internet: The organization ID
In case of custom server: The base URL
In case of institute access: The base URL

If the server cannot be removed it returns the error types/error/error.go Error.

Example Input (3=custom server): RemoveServer(3, "bogus")

Example Output:

{
  "message": {
    "en": "failed to remove server"
  },
  "misc": false
}

RenewSession

Signature:

func RenewSession(c C.uintptr_t) *C.char

RenewSession renews the session of the VPN

This essentially means that the OAuth tokens are deleted. And it also possibly re-runs every state callback you need when getting a config. So least you MUST handle the OAuth started transition

It returns an error if unsuccessful. Example Input: RenewSession(myCookie)

Example Output:

{
  "message": {
    "en": "could not renew session"
  },
  "misc": false
}

ServerList

Signature:

func ServerList() (*C.char, *C.char)

ServerList gets the list of servers that are currently added

This is NOT the discovery list, but the servers that have previously been added with AddServer.

It returns the server list as a JSON string defined in types/server/server.go List. If the server list cannot be retrieved it returns a nil string and an error.

Example Input: ServerList()

Example Output (current profile here is empty as none has been chosen yet):

{
  "institute_access_servers": [
    {
      "display_name": {
        "en": "Demo"
      },
      "identifier": "https://demo.eduvpn.nl/",
      "profiles": {
        "current": ""
      },
      "support_contacts": [
        "mailto:eduvpn@surf.nl"
      ],
      "delisted": false
    }
  ]
}, null

SetProfileID

Signature:

func SetProfileID(data *C.char) *C.char

SetProfileID sets the profile ID of the current serrver.

This MUST only be called if the user/client wishes to manually set a profile instead of the common lib asking for one using a transition.

data is the profile ID.

It returns an error if unsuccessful. Example Input: SetProfileID("splittunnel")

Example Output:

{
  "message": {
    "en": "profile does not exist"
  },
  "misc": false
}

SetSecureLocation

Signature:

func SetSecureLocation(orgID *C.char, cc *C.char) *C.char

SetSecureLocation sets the location for the secure internet server if it exists.

This MUST only be called if the user/client wishes to manually set a location instead of the common lib asking for one using a transition.

orgID is the organisation ID for the secure internet server
cc is the location ID/country code

It returns an error if unsuccessful. Example Input: SetSecureLocation("http://idp.geant.org/", "nl")

Example Output:

{
  "message": {
    "en": "location does not exist"
  },
  "misc": false
}

SetState

Signature:

func SetState(fsmState C.int) *C.char

SetState sets the state of the state machine.

Note: this transitions the FSM into the new state without passing any data to it. Example Input: SetState(5)

Example Output: null

SetTokenHandler

Signature:

func SetTokenHandler(getter C.TokenGetter, setter C.TokenSetter) *C.char

SetTokenHandler sets the token getters and token setters for OAuth.

Because the data that is saved does not contain OAuth tokens for server, the common lib asks and sets the tokens using these callback functions. The client can thus pass callbacks to this function so that the tokens can be securely stored in a keyring.

The client must pass two callback arguments to this function:

getter is the void function that gets tokens from the client. It takes three arguments:

The server for which to get the tokens for, marshalled as JSON and defined in types/server/server.go Current
The output buffer
The length of the output buffer. This 'output buffer' must contain the tokens, marshalled as JSON that is defined in types/server/server.go Tokens

setter is the void function that sets tokens. It takes two arguments:

The server for which to get the tokens for, marshalled as JSON and defined in types/server/server.go Current
The tokens, defined in types/server/server.go Tokens marshalled as JSON

It returns an error when the tokens cannot be set. Example Input: SetTokenHandler(getterFunc, setterFunc)

Example Output: null

StartFailover

Signature:

func StartFailover(c C.uintptr_t, gateway *C.char, mtu C.int, readRxBytes C.ReadRxBytes) (C.int, *C.char)

StartFailover starts the 'failover' procedure in eduvpn-common.

Failover has one primary goal: check if the VPN can reach the gateway. This can be used to check whether or not the client needs to 'failover' to prefer TCP (if currently using UDP). Which is useful to go from a broken WireGuard connection to OpenVPN over TCP.

c is the cookie that is passed for cancellation. To create a cookie, use the CookieNew function
gateway is the gateway IP of the VPN. You MAY calculate this with the CalculateGateway function
readRxBytes is a function that returns the current rx bytes of the VPN interface, this should return a long long int in c

It returns a boolean whether or not the common lib has determined that it cannot reach the gateway. Non-zero=dropped, zero=not dropped. It also returns an error, if it fails to indicate if it has dropped or not. In this case, dropped is also set to zero.

Example Input: StartFailover(myCookie, "10.10.10.1", 1400, myRxBytesReader)

Example Output: 1, null

StartProxyguard

Signature:

func StartProxyguard(c C.uintptr_t, listen *C.char, tcpsp C.int, peer *C.char, proxySetup C.ProxySetup, proxyReady C.ProxyReady) *C.char

StartProxyguard starts the 'proxyguard' procedure in eduvpn-common. eduvpn-common currently also cleans up the running ProxyGuard process in cleanup. If the proxy cannot be started it returns an error.

This function proxies WireGuard UDP connections over HTTP: ProxyGuard on Codeberg.

These input variables can be gotten from the configuration that is retrieved using the proxy JSON key

c is the cookie. Note that if you cancel/delete the cookie, ProxyGuard gets cleaned up. Common automatically cleans up ProxyGuard when Cleanup is called, but it is good to cleanup yourself too.
listen is the ip:port of the local udp connection, this is what is set to the WireGuard endpoint
tcpsp is the TCP source port. Pass 0 if you do not route based on source port, so far only the Linux client has to pass non-zero.
peer is the ip:port of the remote server
proxySetup is a callback which is called when the socket is setting up, this can be used for configuring routing in the client. It takes two arguments: the file descriptor (integer) and a JSON list of IPs the client connects to
proxyReady is a callback when the proxy is ready to be used. This is only called when the client is not connected yet. Use this to determine when the actual wireguard connection can be started. This callback returns and takes no arguments

Example Input: StartProxyGuard(myCookie, "127.0.0.1:1337", 0, "5.5.5.5:51820", proxySetupCB, proxyReadyCB)

Example Output: null

eduVPN-common documentation