net/frr: add per-neighbor local-as option for BGP

[danohn]

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• I opened an issue first for non-trivial changes and linked it below.
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Related issue
If this pull request relates to an issue, link it here:

closes #5307

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Describe the problem
The FRR plugin currently does not allow setting a BGP local-as on a per-neighbor basis. This blocks common interoperability/migration scenarios where a specific peer requires a different local AS than the router’s global BGP AS.

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Describe the proposed solution
This pull request adds neighbor-level local-as support in the FRR plugin:

• Add localas to the BGP neighbor model (IntegerField, range 1..4294967295)
• Add a Local AS field to the BGP neighbor edit dialog
• Render neighbor <address> local-as <asn> in bgpd.conf when configured

The change is backward compatible: no local-as command is emitted unless explicitly configured for a neighbor.

[Monviech]

I guess this looks fine and the change is minimal. The question is how often is this needed. The frr plugin exists since years and you seem to be the first one who misses this.

How common is that migration szenario you are describing? (I don't have a lot of (practical) bgp experience))

There are so many options in the plugin already, we have to be careful to be selective at this point.

[danohn]

I guess this looks fine and the change is minimal. The question is how often is this needed. The frr plugin exists since years and you seem to be the first one who misses this.

How common is that migration szenario you are describing? (I don't have a lot of (practical) bgp experience))

There are so many options in the plugin already, we have to be careful to be selective at this point.

Thanks for taking a look.

You’re right that it’s not a common configuration, which is probably why it hasn’t come up before. However, it is a standard BGP feature used in scenarios like ASN migrations or when peering with providers that require a specific ASN. For example, with AWS Direct Connect it’s fairly common to run a private ASN internally but present a different ASN to AWS using local-as at the neighbor level.

FRR already supports this natively; the PR simply exposes that existing option in the plugin UI. Since it’s optional and only used when explicitly configured, it shouldn’t affect normal setups.

[Monviech]

That sounds good enough for me. Thank you.

Can you bump the minor version in the Makefile and add a changelog to pkg-descr in the style of the other changelogs (contributed by and the pull request link)

Please also do a PR to add this to the documentation here (just the option is enough)
https://github.com/opnsense/docs/blob/7cc8408c4a45bb82c7a83c3fac74b27dbb22e518/source/manual/dynamic_routing.rst

[danohn]

That sounds good enough for me. Thank you.

Can you bump the minor version in the Makefile and add a changelog to pkg-descr in the style of the other changelogs (contributed by and the pull request link)

Thanks @Monviech, here is the commit: d49eed3. I'll work on the docs now in a seperate PR.

[danohn]

Seperate docs PR done 🙂

[Monviech]

Merged, thank you :)