Multicast support

[gev]

Add multicast.

Tested on Linux, Windows, Mac OS.

Example:

moduleDiscovery.ScannerwhereimportControl.ExceptionimportControl.MonadimportData.List.NonEmptyqualifiedasNEimportNetwork.SocketimportNetwork.Socket.ByteStringrunScanner::HostName->HostName->ServiceName->IO()
runScanner host group port =do
host' <- resolve host
group' <- resolve group
let multicast =MulticastGroup (hostAddress group'.addrAddress) Nothing
bracket (socket AF_INETDatagram defaultProtocol) close \sock ->do
bind sock host'.addrAddress
setSockOpt sock AddMembership multicast
forever do
msg <- recv sock 1024print msg
where
resolve addr =NE.head<$> getAddrInfo Nothing (Just addr) (Just port)
hostAddress::SockAddr->HostAddress
hostAddress (SockAddrInet _ addr) = addr
hostAddress _ =error"Unsupported socket address"

moduleDiscovery.AnnoncerwhereimportControl.ConcurrentimportControl.ExceptionimportControl.MonadimportData.List.NonEmptyqualifiedasNEimportNetwork.SocketimportNetwork.Socket.ByteStringrunAnnoncer::HostName->ServiceName->IO()
runAnnoncer group port =do
group' <- resolve group
bracket (socket AF_INETDatagram defaultProtocol) close \sock ->do
forever do
sendAllTo sock "hello" group'.addrAddress
threadDelay 1_000_000where
resolve addr =NE.head<$> getAddrInfo Nothing (Just addr) (Just port)

importControl.Concurrent.AsyncimportControl.MonadimportDiscovery.AnnoncerimportDiscovery.Scannermain::IO()
main = void $ concurrently
do runAnnoncer "239.0.0.1""2026"do runScanner "0.0.0.0""239.0.0.1""2026"

[kazu-yamamoto]

This is a nice work!

[kazu-yamamoto]

Merged.
Thank you!