T6681: Add option for SLAAC to support suppress Interval Advertisement in RA Packets

[rgwan]

Change Summary

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://vyos.dev/T6681

Related PR(s)

Component(s) name

SLAAC, RADVD, IPv6

Proposed changes

MikroTik's IPv6 SLAAC client has a bug, when it received a RA packet with Interval advertisement field, it can't obtain an address correctly from the router.

The log on MikroTik shows like that:

 22:01:50 radvd,debug received Router Advertisement on ether1 from <some mac>
 22:01:50 radvd,debug   prefix: <some prefix> valid: 1800 preferred: 900
 22:01:50 radvd,debug   unsupported option 7

So I'm submitted a patch which allows VyOS don't send Interval advertisement in RA packet.

e.g. the command line will be:

set service router-advert interface <some int> no-send-interval

How to test

Run the command I described above, and use Wireshark to capture packet from router, and the 'Interval Advertisement' field in RA packet is gone.

Smoketest result

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

[github-actions]

👍
No issues in PR Title / Commit Title

[c-po]

Thank you for the contribution. This is a behavioral change to VyOS, as in the past both options got set with a single command set service router-advert interface <some int> no-send-advert.

To preserve existing behavior a migration script is mandatory which will set the new CLI node once it detects that an interface has no-send-advert defined. This will preserve old behavior and add support for users to individually toggle the fields.

[rgwan]

Thank you for the contribution. This is a behavioral change to VyOS, as in the past both options got set with a single command set service router-advert interface <some int> no-send-advert.

To preserve existing behavior a migration script is mandatory which will set the new CLI node once it detects that an interface has no-send-advert defined. This will preserve old behavior and add support for users to individually toggle the fields.

In fact, when no-send-advert is set, the RADVD daemon will not send any router-advertise to the interface, so AdvIntervalOpt option will be omitted by RADVD daemon in this situation.

I don't think we need a migration script for it, it didn't changes old behavior of no-send-advert.

[rgwan]

@c-po So, do you have any further question about this PR? I'm glad to hear from you.

[c-po]

In fact, when no-send-advert is set, the RADVD daemon will not send any router-advertise to the interface, so AdvIntervalOpt option will be omitted by RADVD daemon in this situation.

I don't think we need a migration script for it, it didn't changes old behavior of no-send-advert.

Confirmed:

https://github.com/radvd-project/radvd/blob/f2de4764559e102fe8492520be328858af0f964d/send.c#L880-L885

RADVD code bails out early if no-send-advert is set, thos omitting any other option and not adding a need for a migrator.

[c-po]

@Mergifyio backport sagitta circinus

[mergify]

backport sagitta circinus

✅ Backports have been created

• #4025 T6681: Add option for SLAAC to support suppress Interval Advertisement in RA Packets (backport #4022) has been created for branch sagitta
• #4026 T6681: Add option for SLAAC to support suppress Interval Advertisement in RA Packets (backport #4022) has been created for branch circinus

[c-po]

Added smoketests for the new option

[email protected]:~$ /usr/libexec/vyos/tests/smoke/cli/test_service_router-advert.py
test_advsendadvert_advintervalopt (__main__.TestServiceRADVD.test_advsendadvert_advintervalopt) ... ok
test_common (__main__.TestServiceRADVD.test_common) ... ok
test_deprecate_prefix (__main__.TestServiceRADVD.test_deprecate_prefix) ... ok
test_dns (__main__.TestServiceRADVD.test_dns) ... ok
test_nat64prefix (__main__.TestServiceRADVD.test_nat64prefix) ... ok
test_rasrcaddress (__main__.TestServiceRADVD.test_rasrcaddress) ... ok
test_route (__main__.TestServiceRADVD.test_route) ... ok

----------------------------------------------------------------------
Ran 7 tests in 19.518s

OK