mpls: T4489: Set priority 400 for MPLS after tunnel

[sever-sever]

Change Summary

Fix wrong behavior with priority by using tunnel interfaces
MPLS configuration must be applied after tunnel interfaces
as we use an addition sysctl option net.mpls.conf.tun0.input = 1
which doesn't exist without a tunnel interface

Change priority:

    299 protocols/mpls
    380 interfaces/tunnel

To:

    380 interfaces/tunnel
    400 protocols/mpls

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://phabricator.vyos.net/T4489

Component(s) name

mpls

Proposed changes

How to test

Add tunnel + mpls configuration and check sysctl option net.mpls.conf.tun0.input
Before fix:

set interfaces dummy dum1 address '10.5.4.8/24'
set interfaces tunnel tun0 address '10.255.0.2/30'
set interfaces tunnel tun0 encapsulation 'gre'
set interfaces tunnel tun0 remote '192.0.2.254'
set interfaces tunnel tun0 source-address '192.0.2.1'
set protocols mpls interface 'dum1'
set protocols mpls interface 'tun0'
set protocols mpls ldp discovery transport-ipv4-address '192.0.2.1'
set protocols mpls ldp interface 'dum1'
set protocols mpls ldp interface 'tun0'
set protocols mpls ldp router-id '192.0.2.1'


vyos@r14# sysctl net.mpls.conf.tun0.input
net.mpls.conf.tun0.input = 0

After Fix:

set interfaces dummy dum1 address '10.5.4.8/24'
set interfaces tunnel tun0 address '10.255.0.2/30'
set interfaces tunnel tun0 encapsulation 'gre'
set interfaces tunnel tun0 remote '192.0.2.254'
set interfaces tunnel tun0 source-address '192.0.2.1'
set protocols mpls interface 'dum1'
set protocols mpls interface 'tun0'
set protocols mpls ldp discovery transport-ipv4-address '192.0.2.1'
set protocols mpls ldp interface 'dum1'
set protocols mpls ldp interface 'tun0'
set protocols mpls ldp router-id '192.0.2.1'


vyos@r14# sysctl net.mpls.conf.tun0.input
net.mpls.conf.tun0.input = 1

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly