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Maniphest T4489

MPLS sysctl not persistent for tunnel interfaces
Closed, ResolvedPublicBUG
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Description

Hello,
I have a setup where two VyOS devices have a MPLS link over GRE.

The tunnel is tun0, and the configuration is (relevant part):

set interfaces tunnel tun0 address '10.255.0.2/30'
set interfaces tunnel tun0 encapsulation 'gre'
set interfaces tunnel tun0 remote '10.255.255.1'
set interfaces tunnel tun0 source-address '10.255.255.2'

set protocols mpls interface 'dum1'
set protocols mpls interface 'tun0'
set protocols mpls ldp discovery transport-ipv4-address '10.255.1.2'
set protocols mpls ldp interface 'dum1'
set protocols mpls ldp interface 'tun0'
set protocols mpls ldp router-id '10.255.1.2'

After the configuration, everything looks good and working fine... Until I do a reboot.

In fact, it seems that after the reboot this sysctl flag is not set:

net.mpls.conf.tun0.input = 0

If I perform the following actions:

delete protocols mpls interface tun0
commit
set protocols mpls interface tun0
commit

then the sysctl is restored:

net.mpls.conf.tun0.input = 1

and everything works again.

Details

Difficulty level
Unknown (require assessment)
Version
1.4-rolling-202206270217
Why the issue appeared?
Will be filled on close
Is it a breaking change?
Unspecified (possibly destroys the router)
Issue type
Feature (new functionality)

Related Objects

Event Timeline

ssasso created this task.Jun 27 2022, 12:10 PM
ssasso updated the task description. (Show Details)Jun 27 2022, 12:15 PM
pasik added a subscriber: pasik.Jun 27 2022, 1:08 PM
fernando added a subscriber: fernando.Jun 27 2022, 2:03 PM

hi

it's a common behavior when you want to set sysctl variable and bash-cli is used ( vyos-cli by default when restart the vm set this value in 0 ) . however , it's possible to configure it with this command :

vyos@vyos1-v1# set system sysctl parameter net.mpls.conf.tun0.input value 1

vyos@vyos1-v1# sudo sysctl -a | grep net.mpls.conf.tun0
net.mpls.conf.tun0.input = 1

i'll change it how a feature request , i think that we can enable it when you set mpls ldp and uses a tunnel interface.

fernando changed the task status from Open to Confirmed.Jun 27 2022, 2:05 PM
fernando triaged this task as Low priority.
fernando changed Issue type from Bug (incorrect behavior) to Feature (new functionality).
ssasso added a comment.EditedJun 27 2022, 2:33 PM

Hi,
I think this is a BUG, not a feature.
If I enable mpls on an interface, then the proper sysctl flags must be applied and be persistent.

This is not a flag I want to add on my own. It's a required flag for make MPLS to work.

(it works well when I do the config, but it's not persistent on reboot. I guess the reason is that the mpls commands are launched before the tunnel interface is created, so at that time it's not possible to set the sysctl flag)

ref: https://github.com/vyos/vyos-1x/blob/d32ee4ad297c8754d0841b84b958a12a926cfef9/src/conf_mode/protocols_mpls.py#L123

Viacheslav added a subscriber: Viacheslav.EditedJun 28 2022, 7:53 AM

It seems a wrong priority
Mpls configuration applied before creation tunnel
As a result sysctl parameter for the tunnel interface doesn't exist yet
To reproduce it in one commit:

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

Also similar task for tunnel + sysctl T3813

Viacheslav changed the task status from Confirmed to In progress.Jun 28 2022, 8:03 AM
Viacheslav claimed this task.
Viacheslav added a comment.Jun 28 2022, 8:18 AM

PR https://github.com/vyos/vyos-1x/pull/1370

Viacheslav added a comment.Jun 28 2022, 9:58 AM

Will be fixed in the next rolling release

Viacheslav added a project: VyOS 1.3 Equuleus (1.3.2).Jun 28 2022, 10:42 AM

PR for 1.3 https://github.com/vyos/vyos-1x/pull/1375

Viacheslav closed this task as Resolved.Jul 1 2022, 3:03 PM
Viacheslav moved this task from Need Triage to Finished on the VyOS 1.4 Sagitta board.
Viacheslav moved this task from Need Triage to Finished on the VyOS 1.3 Equuleus (1.3.2) board.
dmbaturin mentioned this in 1.3.2.Sep 5 2022, 3:14 PM
dmbaturin mentioned this in 1.3.2.Sep 15 2022, 10:42 AM