WebRTC native, forcing ports to be allocated in a certain range.

gistfile1.cpp

class PortAllocatorFactoryWrapper : public PortAllocatorFactory {
public:
  PortAllocatorFactoryWrapper(talk_base::Thread* worker_thread, int minPort, int maxPort)
    : PortAllocatorFactory(worker_thread), minPort_(minPort), maxPort_(maxPort) {}

  virtual cricket::PortAllocator *CreatePortAllocator(
      const std::vector<StunConfiguration> &stun,
      const std::vector<TurnConfiguration> &turn) override {
    auto allocator = PortAllocatorFactory::CreatePortAllocator(stun, turn);
    allocator->SetPortRange(minPort_, maxPort_);
    return allocator;
  }
private:
  int minPort_;
  int maxPort_;
};

// Example use: Pass an instance of this factory into CreatePeerConnection.
PeerConnectionInterface *createPeerConnection(
    PeerConnectionFactoryInterface *factory, 
    MediaConstraintsInterface *mediaConstraints, 
    PeerConnectionObserver *observer) 
{
  return factory->CreatePeerConnection(
    PeerConnectionInterface::IceServers(), 
    mediaConstraints, 
    new talk_base::RefCountedObject<PortAllocatorFactoryWrapper>(
      static_cast<PeerConnectionFactory *>(factory.get())->worker_thread(),
      portRange.first,
      portRange.second),
    nullptr,
    observer);
}

Nice!

Nice ! Please note that static_cast<PeerConnectionFactory *>(factory.get())->worker_thread() can be replaced with rtc::Thread::Current() => cleaner, shorter, safer 👍