This was a huge work, but now UDP is usable as seen in the examples.
Instead of relying on 'connect()', just do 'sendto()' and 'recvfrom()'
as they are universal. Multicast address can only be connected in
IPv4, IPv6 wasn't working and I'm not sure the IPv4 is portable to
other platforms.
Dialer will auto-join multicast groups is the dialed address is
one. Multicast properties such as time to live (hops) and loopback can
be configured. When joining multicast groups, the local
address/interface can be configured by 'IP@IFACE' format, with
'@IFACE' being optional.
Dialers will now auto-bind, so it can receive data as dialers are
expected to be bi-directional. One can manually specify the binding
address if there is such need.
Since datagrams must be read in their full size, otherwise the
remaining bits are dropped, expose next_datagram_size_query() in both
Efl.Net.Socket.Udp and Efl.Net.Server.Udp.Client.
To finalize UDP for real we need to introduce an 'Efl_Net_Ip_Address'
structure to serve as both IPv4 and IPv6 and expose 'sendto()' and
'recvfrom()'. These will come later as this commit is already too big.
Like existing ecore_con code, this does not use SOCKSv5 UDP
proxy. It's kinda cumbersome to add since requires a keep alive TCP
connection to the server, a second UDP channel and framing around the
original UDP frame.
Added UDP_CORK (if present) to match TCP_UDP present in TCP sockets,
this allows one to execute multiple write() calls that will result in
a single datagram, generated when CORK becomes FALSE again.
The efl_io_copier_example.c now accepts this as output. There is no
input UDP as there is no way to notify the server of a connection
(since such thing doesn't exit), usually servers react after a
datagram is received, replying to the source.
Gustavo Sverzut Barbieri