Mistake of SNI extention handling

[hayden-pan]

Maybe the code below is getting the server name from wrong place when the dtls server handling SNI extension.
I think the server should get the server name from the state of the connection, which variable name is state in this function scope. Am I right?

dtls/flight4handler.go

Lines 204 to 208 in d01fc85

	if cfg.localPSKCallback == nil {
	certificate, err := cfg.getCertificate(cfg.serverName)
	if err != nil {
	return nil, &alert{alertLevelFatal, alertHandshakeFailure}, err
	}

[Sean-Der]

Hey @aaftio sorry I missed this.

I believe you are correct! I think this was broken in 863572a would you be interested in submitting a PR to fix this? It would also be great if you could write a failing test so this doesn't break again.

If you don't have the time to fix this mind just telling me, and I will fix when I get time!

thank you

[hayden-pan]

@Sean-Der , I am glad to fix it when I get time. Maybe a week later if not in a hurry.

[Sean-Der]

No hurry at all! Thanks for getting involved :)