add VPP patch to preserve interface self LL receive DPO#914
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Nodes can lose the local IPv6 link-local receive route (dpo-receive) from the ip6-ll FIB, which breaks all link-local control traffic (DHCPv6, NDP) to the interface's own address until the link-local /128 is manually re-added. Root cause in VPP: - ip6_link installs the interface LL /128 as local (FIB_ROUTE_PATH_LOCAL) in the ip6-ll table. - ip_neighbor and teib can also update/delete LL /128 entries as non-local adjacency paths (FIB_ROUTE_PATH_FLAG_NONE). - All such operations share FIB_SOURCE_IP6_ND in the same LL FIB. - A self-LL entry (same peer IP as interface's own LL on same sw_if) can overwrite local receive semantics; later age-out/ delete operations can remove the /128 entirely. The patch detects self-link-local in ip_neighbor/teib, skips non-local LL add/remove for self entries, and restores local LL route as safeguard. Signed-off-by: Aritra Basu <aritrbas@cisco.com>
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sknat
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Feb 26, 2026
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Nodes can lose the local IPv6 link-local receive route (
dpo-receive) from the ip6-ll FIB, which breaks all link-local control traffic (DHCPv6, NDP) to the interface's own address until the link-local/128is manually re-added usingset int ip addr <intf> fe80::<addr>/128Root cause in VPP:
ip6_linkinstalls the interface LL/128as local (FIB_ROUTE_PATH_LOCAL) in the ip6-ll table./128entries as non-local adjacency paths (FIB_ROUTE_PATH_FLAG_NONE).FIB_SOURCE_IP6_NDin the same LL FIB.sw_if) can overwrite local receive semantics; later age-out/ delete operations can remove the/128entirely.The patch detects self-link-local in ip_neighbor/teib, skips non-local LL add/remove for self-entries, and restores local LL route as safeguard.