This patch addresses two problems. First tcp_connections were not being closed, leading to a bug report about socket exhaustion [1]. Second, socket_pdu_impl tracks tcp_connections in a vector so that it can broadcast outgoing data to clients. Items in this vector were never freed. This patch does a shutdown and close on the tcp_connection when there is a read failure (signaling a socket close). On each new accept, the tcp_connection list in socket_pdu_impl is scanned for closed connections, which are then removed. Possible improvements: - Make sure the read error is eof. - Check sends as well as reads. More direct signalling could be done between tcp_connection and socket_pdu_impl, but that would require an API change. No change is required, here. [1] https://github.com/gnuradio/gnuradio/issues/1568