tcp: Close Server on Max Connections

[twoeths]

• Version: 7.0.1

• Platform: Linux feat2-lg1k-hzax41 5.15.0-73-generic #80-Ubuntu SMP Mon May 15 15:18:26 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

• Subsystem:

Severity:

Medium

Description:

• libp2p is designed to close server on max connections, however it's only count on inbound connections, it should count on total connections instead https://github.com/libp2p/js-libp2p/blob/5ffa7a74d5b972bdac387782d6010b6a19558600/packages/transport-tcp/src/listener.ts#L68C20-L68C31

• in lodestar, normally maxConnections is configured as 55 peers. However total peers could be more than that

  • libp2p_tcp_inbound_connections_total is consistently <= 55

- however total peers could be more than that because there are outbound connections also

Steps to reproduce the error:

[wemeetagain]

To give more detail to this issue:

• The TCP listener can be configured to close when a certain number of connections is reached with the closeServerOnMaxConnections option
• This option currently only looks at inbound connections when considering when to close the listener
• The current behavior makes the option significantly less useful because consumers are not able to configure a # of max connections on which to stop listening, rather only can configure a # of max inbound connections on which to stop listening
• This issue requests updating the behavior of the closeServerOnMaxConnections option to consider both # of inbound and # of outbound in determining when to stop listening.