I know how to send byte data to a server via the udp protocol. How can I activate some flags on the package that I am sending? How can I tel if a package that is received has some flags activated. Moreover how can I read the checksum contained by the package? If I want to send a package with no data and just a flag how can I do that? I want to do this with c#. I dont want to modify the local endpoint nor the remote endpoint nor anything else about each package.
Edit
The reason why I want to do this is because I have tried so hard to do tcp punch holing. I opened a bounty question at forward traffic from port X to computer B with c# "UDP punch hole into firewall" anyways I managed to do udp punch holing. As a result I want to make udp reliable.
In other words I want to create an algorith that will enable me to send udp packages reaching their destination in the right order. If I could set on and read some of the flags then that will facilitate this algorithm.
I know it will not be eassy to create but at least I want to give it a try. I been waisting a lot of time finding a c# library that does this…
UDP already has a checksum.
Did you mean to ask about something like RUDP? This allows you to guarantee packet delivery and ordering (both, none, or either). Lidgren implements a reliable UDP protocol.
If you want to roll your own, read up on how SEQ and ACK work in TCP; and emulate that over UDP (which is what Lidgren basically does).