Ability to specify whether to pad crypto properties when creating an outbound sip gateway using SRTP

[davehorton]

An area of confusion in the industry is whether or not to apply base64 padding (ie 0, 1, or 2 "equals" signs) to inline crypto attributes in the SDP. Example with no padding:

a=crypto:1 AEAD_AES_256_GCM inline:UjbSu5pCEPs/D7UtQWl2R+Nd7YnXoiGU6+THDz58hyXTtt94HiGM8YgCgU0
a=crypto:2 AEAD_AES_128_GCM inline:6Y7fx0D8q3OZxwKqOmQg0uD/ubV0mtgHSoj2wQ
a=crypto:3 AES_CM_128_HMAC_SHA1_80 inline:QEg6UozMTrNtbMEWLMEHvIuQ4hQSQ/UHkJm9b6sd

Example with padding:

a=crypto:1 AEAD_AES_256_GCM inline:UKQQltkBs5PsDa37SL7uEgYG3BFXDIIqYeorn76ERCcNk4poY02D/fWU74E=
a=crypto:2 AEAD_AES_128_GCM inline:hI8twp7i82SjaofbxTw7XNyrvOmqvx3A50Y4QA==
a=crypto:3 AES_CM_128_HMAC_SHA1_80 inline:ONE4xh9E7LfpxCoORp1awnUI3+IZdftiGbDQNwRK

Currently, we have an env var in SBC outbound, PAD_CRYPTO, that globally sets which way to do it. However, we should be able to set this on a sip gateway level. When the user selects "TLS/SRTP" for the protocol for an outbound SIP gateway there should appear a checkbox labeled "Pad crypto attributes". By default it should be unchecked. This setting should define whether or not for any outbound calls made through to gateway padding should be added.

[davehorton]

Below is a wireframe showing the new property, which is only visible for outbound gateways where TLS/SRTP is selected

[xquanluu]

closing this as PRs merged