如何从套接字错误中恢复？ (10040)

Question

I have a UDP sender and a UDP listener. Transfering messages works nicely. But...

It appears when I am overfeeding (sending sustained data quickly) the listening socket may throw on the call to ReceiveFrom with error code 10040 which means some buffer was not large enough. The exception message is

A message sent on a datagram socket was larger than the internal message buffer or some other network limit, or the buffer used to receive a datagram into was smaller than the datagram itself.

Fair enough. But the problem is I will then get this exception on every following call to ReceiveFrom. The socket appears broken. I am willing to accept the transfer failed but I now want to flush the socket's receive buffer and continue.

I can prevent this from happening by setting a substantial receive buffer size of 128K on the listening socket (as opposed to the default of 8K). I can also fix it by having the sender pause for 1 ms after sending a chunk of 65507 bytes of a multi-chunk bulk message.

But I do not feel safe. If this exception still occurs, I want to log and continue (better luck next time). Recreating the socket and restarting the listen thread seems blunt. Is there a better way?

Something unrelated I do not like: Socket.ReceiveFrom throws an exception after the timeout. This is stupid, timeouts are normal behavior. I would expect a TryReceiveFrom method and I do not like using the exception handler as a flow control statement, which seems to be the only option I have. Is there a better way?

Answer 1

I accept now that when the buffer overruns, the socket is broken and needs to be recreated.

The exception being thrown after a timeout of Socket.ReceiveFrom can be prevented by first checking if any data is available using the Socket.Poll method. This has its own timeout argument. So it is pointless to set ReceiveTimeout on the socket, using Poll in tandem with ReceiveFrom works much nicer.