Issue description

I have successfully setting sni for some domain, it worked. But right now I need setting sni for ip, I have generated some self signed certs with ip, but get error failed to find any SSL certificate by SNI: xx.xx.xx.xx, context: ssl_certificate_by_lua*, client: 10.14.0.218, server: 0.0.0.0:9443 . Well I dig the issues and found someone said the sni doesnot support ip. So how can I force to use a self signed cert for ip in apisix just like native nginx.

Environment

• apisix version 2.1
• OS: apache/apisix:2.1-alpine
• OpenResty / Nginx version:

Minimal test code / Steps to reproduce the issue

1. generate a self signed cert for ip
2. upload it to apisix via dashboard
3. create a route with an ip for Domain name
4. test the route and got error

What's the actual result? (including assertion message & call stack if applicable)

failed to find any SSL certificate by SNI: xx.xx.xx.xx, context: ssl_certificate_by_lua*, client: 10.14.0.218, server: 0.0.0.0:9443 in error.log

What's the expected result?

could work like domain route