seemk / urn

UDP relay for network I/O scalability testing

UDP relay for network I/O scalability testing

UDP relay mimicks TURN relay:

• client connects to relay on port 3478 and registers itself using random 64-bit integer
• peer sends data to port 3479 with same 64-bit integer that client used for registering
• relay forwards packets sent by peer to client

This creates simple platform to experiment with different relay network I/O patterns and threading models. Relaying logic is isolated into very simple header-only urn library that can be separately tested and benchmarked.

For testing different I/O and/or threading models, create new experiment executable sub-project that provides syscall wrappers and invokes business logic hooks. Business logic is implemented by class urn::relay<Library, MultiThreaded>.

Library should provide following API:

struct Library
{
  using endpoint = /* source/destination endpoint */

  struct packet
  {
    std::byte *data ();
    size_t size ();
  };

  struct client
  {
    // Start receive on client port
    // On completion, invoke relay<Library>::on_client_received()
    void start_receive ();
  };

  struct peer
  {
    // Start receive on peer port
    // On completion, invoke relay<Library>::on_peer_received()
    void start_receive ();
  };

  struct session
  {
    // Construct new session with associated endpoint \a src
    session (const endpoint &src);

    // Start sending \a data to associated endpoint
    // On completion, invoke relay<Library>::on_session_sent()
    void start_send (packet &&p);
  };
};

Compiling and installing

$ mkdir build && cd build
$ cmake .. [-Durn_unittests=yes|no] [-Durn_benchmarks=yes|no] [experiment(s)]
$ make && make test

Experiments:

• -Durn_libuv=yes|no libuv-based experiment (https://github.com/svens/urn/blob/master/libuv/relay.hpp)

Notes:

• make builds all enabled experiments
• make test tests only business logic

Source tree

The source tree is organised as follows:

.               Root of source tree
|- urn          Platform-independent packet relay library
|- bench        Business logic benchmarks
|- cmake        CMake modules
|- extern       External code as git submodules
`- libuv        [libuv](https://github.com/libuv/libuv) based experiment