Adding join/leave to UDPSocket

[kydos]

It would be nice to add join/lease operations to the UDPSocket to facilitate the joining/leaving of multicast groups. Today the operation can be achieved by using setsockopt and could be already made a bit more user friendly by addressing the Issue #125. However, the most user-friendly solution would be to add join/leave operations straight on the UDPSocket class.

Below a possible implementation for the functionality:

  private func createMembershipRequest(_ ip: String, _ ifaddr: String) -> ip_mreq {
        let group = inet_addr(ip)
        let iface = inet_addr(ifaddr)
        var imr =  ip_mreq()
        imr.imr_multiaddr.s_addr = group;
        imr.imr_interface.s_addr = iface
        return imr
    }
    
    public func join(group mcastAddr: String, iface ifname: String) throws {
        let imr = self.createMembershipRequest(mcastAddr, ifname)
        try self.descriptor.setOption(level: IPPROTO_IP, name: IP_ADD_MEMBERSHIP, value: imr)
    
    }
    
    public func leave(group mcastAddr: String, iface ifname: String) throws {
        let imr = self.createMembershipRequest(mcastAddr, ifname)
        try self.descriptor.setOption(level: IPPROTO_IP, name: IP_ADD_MEMBERSHIP, value: imr)
    
    }

Ciao, Kydos

[tanner0101]

This code looks good. Would you want to submit a PR to implement this feature?

[kydos]

I've done a bunch of other enhancements on my branch. Let me finalise my contribution and then I'll do a Pull Request. Among other things I have a buffer a la java.nio.ByteBuffer to contribute along with send/rcv operations on the socket that operate on this ByteBuffer w/o allocating memory at each time.

I'll probably have things cleaned up and committed on my branch by later today.

-- Kydos

[tanner0101]

We've moved to a new, streaming TCP setup in Vapor 3. If you're interested in submitting code for that, please open a PR. Thanks!