NethVoice: SRTP not working if one extension in the dial string has it disabled

[Stell0]

If one of the extensions in the dial string has SRTP disabled, isTrunk = 1 header is used for all extensions called. This is because the freepbx func-set-sipheaders is called once before the Dial, but then func-apply-sipheaders is called once for each extension in the dial with always the same headers.

The consequence is that if the encrypted extension has strict SRTP (like it is for the mobile app), call fails

This bug is introduced with nethesis/ns8-nethvoice#489

Steps to reproduce

• give to an user two devices, one encrypted one not encrypted
• call user

Expected behavior

• isTrunk=1 header should be present only in the INVITE for the unencrypted extension

Actual behavior

• both INVITE has isTrunk=1 header

Workaround

• Enable encryption for all user's extensions

See also

https://mattermost.nethesis.it/nethesis/pl/p8ncyx9j87yqzfkr9idghezxoa

[Stell0]

Test case:

• verify that the bug is no more reproducible
• make sure that outbound calls to trunks that needs isTrunk=1 still has the isTrunk=1 header

[Stell0]

1.4.1-testing.1

[Amygos]

Testing release nethesis/ns8-nethvoice 1.4.1-testing.1