Add externalIPv4/externalIPv6 configs and API methods for them

[prlanzarin]

What is the current behavior you want to change?

Currently, externalAddress allows only for a single IP that will be either IPv4 or IPv6. That's not friendly with dual stack IPv4+IPv6 environments.

Fixes Kurento/bugtracker#522

What is the new behavior provided by this change?

This pull request splits the externalAddress config into two new ones

• externalIPv4
• externalIPv6

They can be used concurrently and will mangle compatible IPv_X candidates.

externalAddress will still have precedence of these two new options: if it's set, externalIPv4/externalIPv6 will be ignored

From the WebRtcEndpoint.conf.ini explanation:

;; External IPv4 address of the media server.
;;
;; This setting follows the same rationale of the externalAddress setting, but
;; the idea here is to couple it with the externalIPv6 setting to achieve dual
;; stack IPv4+IPv6 candidate mangling.
;;
;; Right now, externalAddress only allows a single IP (which has to be either
;; IPv4 or IPv6), so it's not dual stack friendly. This option will mangle
;; IPv4 candidates with the specified one.
;;
;; For the sake of backwards compatibility, externalAddress has preference over
;; this: when externalAddress is set, this option will be ignored.
;;
;; <externalIPv4> is an IPv4 address.
;;
; externalIPv4=10.20.30.40

;; External IPv6 address of the media server.
;;
;; Refer to the detailing of externalIPv4 which should explain this as well.
;;
;; For the sake of backwards compatibility, externalAddress has preference over
;; this: when externalAddress is set, this option will be ignored.
;;
;; <externalIPv6> is an IPv6 address.
;;
; externalIPv6=2001:0db8:85a3:0000:0000:8a2e:0370:7334

How has this been tested?

• Compiled on 16.04
• Manually tested:
  • WebRtcEndpoint.conf.ini#externalIPv4/IPv6: IPv4|IPv6, by observing about:webrtc and chrome:webrtc-internals dumps to verify the generated server-side candidates and see if they match the configured values. Also bumped KMS's logs to see if they right, compatible candidates were being mangled.
  • WebRtcEndpoint#setExternalIPv4/IPv6(IPv4|IPv6), via the JS client, to verify the generated server-side candidates and see if they match the configured values. Also bumped KMS's logs to see if they right, compatible candidates were being mangled.
  • Pending: unit tests

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature / enhancement (non-breaking change which improves the project)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• My change requires a change to the documentation
• My change requires a change in other repository

Checklist

• I have read the Contribution Guidelines
• I have added an explanation of what the changes do and why they should be included
• I have written new tests for the changes, as applicable, and have successfully run them locally

[jenkinskurento]

Hi there, thanks for your Pull Request!

A Kurento member needs to verify that this patch is reasonable to test. In case it is, they should write a comment with the phrase test this please. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by Kurento members will still work. Regular contributors can be whitelisted to skip this step.

[j1elo]

Amazing addition! thank you very much. I'm right now adding a couple of easy unit tests, and this will be ready for merging.

[j1elo]

I think this should deprecate the externalAddress setting, as users could now configure both externalIPv4 and externalIPv6 to their desired values. What do you think?

[prlanzarin]

@j1elo Yeah, agreed.