bgpd: honor 'no activate' for dynamic neighbors in peer-group

[enissim]

When a dynamic peer connects via 'bgp listen range', peer_create() activates IPv4 unicast by default. peer_create_bind_dynamic_neighbor() then applies the group's AF config but only activates AFIs the group has enabled -- it never deactivates AFIs the group has disabled. This causes 'no neighbor activate' under an address-family to be ignored for dynamic peers.
Add peer_deactivate() for AFIs the group has deactivated, matching the fix in peer_group_bind() from commit 5f00745 ("bgpd: peer-group members 'activate' when they shouldn't").

[greptile-apps]

Greptile Summary

This PR fixes a bug where dynamic peers (created via bgp listen range) would ignore no neighbor <group> activate under an address-family. peer_create() always enables IPv4 unicast by default; peer_create_bind_dynamic_neighbor() only activated group-enabled AFIs but never deactivated the defaults. The fix mirrors the existing pattern in peer_group_bind() by calling peer_deactivate() for each AFI/SAFI the group has not enabled, ensuring the peer's active address families exactly match the group's configuration.

Confidence Score: 5/5

This PR is safe to merge — the change is minimal, correct, and directly mirrors an existing proven fix in peer_group_bind().

The fix is a 4-line addition that replicates the exact same else if (peer->afc[afi][safi]) peer_deactivate(peer, afi, safi) logic already present in peer_group_bind(). peer_deactivate() handles newly created (non-established) peers correctly by clearing afc and deleting the peer_af structure. No P0/P1 issues found.

No files require special attention.

Important Files Changed

Filename	Overview
bgpd/bgpd.c	Adds peer_deactivate() for AFIs the group has disabled in peer_create_bind_dynamic_neighbor(), mirroring the existing fix in peer_group_bind() — correct, minimal, and well-targeted.

Sequence Diagram

sequenceDiagram
    participant TCP as Incoming TCP
    participant BGP as bgpd
    participant PCBDN as peer_create_bind_dynamic_neighbor()
    participant PC as peer_create()
    participant PD as peer_deactivate()

    TCP->>BGP: Dynamic peer connects (bgp listen range)
    BGP->>PCBDN: peer_create_bind_dynamic_neighbor(bgp, su, group)
    PCBDN->>PC: peer_create(...) — activates IPv4 unicast by default
    PC-->>PCBDN: peer (with afc[AFI_IP][SAFI_UNICAST]=1)
    PCBDN->>PCBDN: peer_group2peer_config_copy(group, peer)
    loop FOREACH_AFI_SAFI
        alt group->conf->afc[afi][safi] == 0 (group has disabled this AF)
            Note over PCBDN,PD: NEW: deactivate the AF the group does not want
            PCBDN->>PD: peer_deactivate(peer, afi, safi)
            PD->>PD: non_peergroup_deactivate_af() sets afc=0, deletes peer_af
        else group->conf->afc[afi][safi] == 1 (group has enabled this AF)
            PCBDN->>PCBDN: peer->afc[afi][safi] = 1, peer_af_create(), peer_group2peer_config_copy_af()
        end
    end
    PCBDN-->>BGP: peer (AFs match group exactly)

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_{Reviews (1): Last reviewed commit: "bgpd: honor 'no activate' for dynamic ne..." | Re-trigger Greptile}

[ton31337]

@Mergifyio backport stable/10.6 stable/10.5 stable/10.4

[mergify]

backport stable/10.6 stable/10.5 stable/10.4

✅ Backports have been created

Details

• #21659 bgpd: honor 'no activate' for dynamic neighbors in peer-group (backport #21658) has been created for branch stable/10.6
• #21660 bgpd: honor 'no activate' for dynamic neighbors in peer-group (backport #21658) has been created for branch stable/10.5
• #21661 bgpd: honor 'no activate' for dynamic neighbors in peer-group (backport #21658) has been created for branch stable/10.4