[patches-sonic]: Drop the bridge FDB protocol and unused NTF_EXT_VALIDATED patches - #619
[patches-sonic]: Drop the bridge FDB protocol and unused NTF_EXT_VALIDATED patches#619tahmed-dev wants to merge 2 commits into
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Nothing consumes the flag. It exists for EVPN multihoming neighbour proxy advertisement, and FRR implements that in user space through its own ZEBRA_NEIGH_ES_PEER_PROXY state rather than asking the kernel, so neither FRR nor any SONiC daemon references NTF_EXT_VALIDATED or extern_valid. The series note claimed the flag was already upstream at 6.12, but it is absent from the 6.12.41 tree we build, so that was not the reason to drop it either way. The EVPN MH patches that remain are load bearing: NDA_FLAGS_EXT carries NTF_E_MH_PEER_SYNC, and the bridge FDB protocol field is what records whether a MAC was learned by the hardware or by zebra. Signed-off-by: Tamer Ahmed <tamerahmed@microsoft.com>
NDA_PROTOCOL on a bridge FDB entry is not upstream, and nothing needs it any more. Where a MAC came from now travels over the FPM channel, so zebra no longer has to read an origin tag back off the kernel entry, and it no longer writes one. fdbsyncd still spells "proto hw" on its kernel path, but it probes for support at startup and drops the tag when the kernel does not accept it, so removing this patch degrades that path rather than breaking it. The NDA_FLAGS_EXT patch stays: it carries NTF_EXT_MH_PEER_SYNC for EVPN multihoming, which is a separate feature and is not upstream either. Signed-off-by: Tamer Ahmed <tamerahmed@microsoft.com>
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The PR direction looks right, but the commit text says fdbsyncd still spells "proto hw" and probes/falls back when the kernel does not accept it. The matching SWSS PR appears to remove the bridge FDB proto probe/path and simply omits proto on the legacy kernel path. Can we update the commit message / PR description to say the legacy kernel path intentionally runs without the SONiC FDB protocol extension, matching the pre-proto behavior? |
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Can we confirm the remaining patch stack applies cleanly and boots with only 0001-vxlan-bridge-Add-NDA_FLAGS_EXT-support-with-NTF_EXT_... left under the EVPN MH section? The important validation is that NTF_EXT_MH_PEER_SYNC still works after removing the protocol and extern_valid patches.
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Why I did it
Two SONiC kernel patches exist only to support MAC learning through the Linux
bridge FDB. With MAC synchronization moved onto the FPM channel, they are no
longer needed, and carrying out-of-tree kernel patches has an ongoing cost at
every kernel rebase.
0002-net-bridge-vxlan-Protocol-field-in-bridge-fdb.patchadds anNDA_PROTOCOLfield to the bridge/vxlan FDB and, more significantly, makesdeletes protocol-scoped so control-plane and data-plane entries can coexist.
That arbitration belongs in SONiC, not in the kernel, and nothing issues those
protocol-scoped deletes once MAC state is carried over FPM.
0003-neighbor-Add-NTF_EXT_VALIDATED-flag-for-externally-v.patchis unused.There are zero references across the FRR tree and the SONiC daemons. It is for
EVPN-MH neighbour proxy advertisement, which FRR implements in user space via
ZEBRA_NEIGH_ES_PEER_PROXYwithout asking the kernel. It also went upstreamaround 6.16.
How I did it
Remove both patch files and their entries from
patches-sonic/series.Patch
0001-vxlan-bridge-Add-NDA_FLAGS_EXT-support-with-NTF_EXT_.patchisdeliberately retained: it defines
NTF_EXT_MH_PEER_SYNC, which FRR consumesfor EVPN multihoming peer sync. That is a separate feature and out of scope here.
How to verify it
The remaining series applies cleanly and the kernel builds. Booted on an Arista
7060X6-64PE-B pair.
Dependency / merge order
This PR must merge LAST. On master today,
sonic-swssfdbsyncd stillcontains the kernel FDB protocol plumbing and
sonic-buildimagestill ships theiproute2
protopatch that these kernel patches support. Merging this firstwould remove kernel support that shipping code still depends on.
Required to merge first:
sonic-swss: drops the dead kernel FDB protocol plumbingsonic-buildimage: drops the iproute2 bridge FDB protocol field patchWhich release branch to backport
None requested at this time.
Description for the changelog
Drop the bridge FDB protocol field and unused NTF_EXT_VALIDATED kernel patches.