Issues accessing the SNI (server name) from the TLS inspector within External Authorization CheckRequest about envoy HOT 5 CLOSED

cc @ggreenway @KBaichoo @esmet @tyxia

from envoy.

The documentation isn't clear about this, but include_tls_session only works when using a tls transport socket. This could probably be fixed to also work with TlsInspector; a PR to do that would be welcome.

from envoy.

@ggreenway Thanks for the clarification. Are you able to give me a few hints about where to look in the code about where the external auth looks at the transport socket when include_tls_session is true? I presume I could just read the server name from SNI (i.e. TLS inspector) and then are probably filters that already read it like the SNI dynamic forward proxy.

from envoy.

Start by looking here and here. And then look at how the sni dynamic forward proxy is looking it up, and in CheckRequestUtils::setTLSSession if the existing path is empty, check the value from tls inspector.

from envoy.

@ggreenway #34100 is my attempt to handle this. I'm having troubles understanding what exact unit test (or tests) that I broke. I know the file, just not which tests.

from envoy.