# EduVPN shared library

This repository contains a Go library with functions that all EduVPN clients can use. The goal is to let EduVPN clients
link against this library and gradually merge more common logic between EduVPN clients into this repository.

cgo is used to build the go library into a shared dynamic library. Wrappers will be written using some FFI framework for
each language used in EduVPN clients to easily interface with the library.

## Functionality

Currently, only verification of signatures on files from `disco.eduvpn.org` is supported. For now, these files have to
be downloaded by the caller.

## Requirements

To run the Go tests, you will need [Go](https://go.dev/doc/install) 1.15 or later (add it to your `PATH`). To build the
shared library, you will additionally need to install gcc. If you want to use the Makefile scripts you will need GNU
make.

On Windows, you can install gcc and make (or even Go) via MinGW or Cygwin or use WSL. For MinGW:

1. [Install MinGW](https://www.msys2.org/#installation) (you don't need to install any extra packages yet) and open some
   MSYS2 terminal (e.g. from the start menu or one of the installed binaries)
2. Install the [`make`](https://packages.msys2.org/package/make?repo=msys) package (`pacman -S make`) (or
   e.g. [`mingw-w64-x86_64-make`](https://packages.msys2.org/package/mingw-w64-x86_64-make?repo=mingw64) and
   use `mingw32-make` in the command line)
3. To compile for x86_64:
   1. Install the [`mingw-w64-x86_64-gcc`](https://packages.msys2.org/package/mingw-w64-x86_64-gcc?repo=mingw64) package
   2. Open the MinGW 64-bit console, via the start menu, or in your current
      terminal: `path/to/msys64/msys2_shell.cmd -mingw64 -defterm -no-start -use-full-path`
   3. Run the make commands in the project directory
4. To compile for x86 (32-bit):
   1. Install the [`mingw-w64-i686-gcc`](https://packages.msys2.org/package/mingw-w64-i686-gcc?repo=mingw32) package
   2. Open the MinGW 32-bit console, via the start menu, or in your current
      terminal: `path/to/msys64/msys2_shell.cmd -mingw32 -defterm -no-start -use-full-path`
   3. Run the make commands in the project directory

Take a look at `wrappers/<lang>/README.md` for extra instructions for each wrapper.

## Build & test

Build shared library for current platform:

```shell
make
```

Build shared library for specified OS & architecture (example):

```shell
make GOOS=windows GOARCH=386
```

Results will be output in `exports/`.

TODO: notes on cross-compilation

Test Go code:

```shell
make test-go
```

Test wrappers (you will need compilers for all wrappers if you do this):

```shell
make test-wrappers
```

Take a look at `wrappers/<lang>/README.md` for descriptions per wrapper.

## Directory

- `verify.go`: main API
- `verify_test.go` and `test_data/`: tests for API
- `exports/`: C API interface
- `wrappers/`: Wrappers per language, more will be added