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 were 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.

⚠️ The caller has to extract the timestamp from the file (JSON "v" tag), save it, and pass it to the Verify function the next time that they call it. This prevents a rollback of a previous file. This functionality may be integrated into the library in the future.

Requirements

To run the Go tests, you will need Go 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 (not bsd make).

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

1. Install MinGW (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 package (pacman -S make) (or e.g. mingw-w64-x86_64-make and use mingw32-make in the command line)
3. To compile for x86_64:
   1. Install the mingw-w64-x86_64-gcc 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 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:

make

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

make GOOS=windows GOARCH=386

To list all platforms supported by cgo, run go tool dist list.

Results will be output in exports/lib/.

Usually you will need to specify the compiler when cross compiling, for example:

make GOOS=windows GOARCH=amd64 CC=x86_64-w64-mingw32-gcc

For example, you can cross compile for Windows from Linux using MinGW-w64.

Test Go code:

make test-go

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

make test-wrappers

Specify -j to execute tests in parallel. You can specify specific wrappers to test by appending e.g. WRAPPERS="csharp php".

Test both:

make test

Clean built libraries and wrapper builds:

make -j clean

Usually you won't need to do this, as changes in the library should automatically be incorporated in wrappers. Specify CLEAN_ALL=1 to also remove downloaded dependencies for some wrappers. You can clean individual wrappers by executing clean in their directories, or specify WRAPPERS=....

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

Structure

• verify.go: main API
• verify_test.go and test_data/: tests for API
• exports/: C API interface
• exports/lib/: built libraries per architecture per OS
• wrappers/: wrappers per language