RUBY-1140 Add TLS SNI support

[estolfo]

No description provided.

[jyemin]

Seems reasonable, but having run into issues in Java you should do some manual testing for the following cases:

1. An IPv4 literal
2. An IPv6 literal

for both MRI and JRuby.

[durran]

LGTM

[estolfo]

This doesn't seem to work for JRuby.

I'm setting the hostname as indicated here

but the server logs show:
new ssl connection, SNI server name []

for MRI, it shows:
new ssl connection, SNI server name [server]

[behackett]

If JRuby doesn't support it (it's undocumented in MRI, so no surprise) then oh well. Open a ticket against MRI to get it documented, and against JRuby to get it implemented. I couldn't implement it for all the versions of python we support either.

[estolfo]

So in the Python driver, you only set the hostname for certain versions of Python?

[behackett]

Yep, only versions of python that support SNI.

https://docs.python.org/2/library/ssl.html#ssl.HAS_SNI

[jyemin]

There's a claim that it's implemented here: jruby/jruby#349. But the comment saying that SNI is supported starting with Java 7 doesn't jibe with my experience. The Java driver's SNI support relies on a Java 8 feature: https://docs.oracle.com/javase/8/docs/api/javax/net/ssl/SSLParameters.html#setServerNames-java.util.List-

[estolfo]

I opened a ticket with the openssl library for JRuby. Hopefully I'll get some more info soon from the JRuby team directly...
jruby/jruby-openssl#103

[estolfo]

fyi, the Ruby team updated their docs: https://bugs.ruby-lang.org/issues/12740

[estolfo]

Cannot support this for JRuby until they resolve the bug in openssl:
https://twitter.com/EmStolfo/status/775615814737231872