+125
−71
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vxlan: support fdb and learning in COLLECT_METADATA mode
Vxlan COLLECT_METADATA mode today solves the per-vni netdev
scalability problem in l3 networks. It expects all forwarding
information to be present in dst_metadata. This patch series
enhances collect metadata mode to include the case where only
vni is present in dst_metadata, and the vxlan driver can then use
the rest of the forwarding information datbase to make forwarding
decisions. There is no change to default COLLECT_METADATA
behaviour. These changes only apply to COLLECT_METADATA when
used with the bridging use-case with a special dst_metadata
tunnel info flag (eg: where vxlan device is part of a bridge).
For all this to work, the vxlan driver will need to now support a
single fdb table hashed by mac + vni. This series essentially makes
this happen.
use-case and workflow:
vxlan collect metadata device participates in bridging vlan
to vn-segments. Bridge driver above the vxlan device,
sends the vni corresponding to the vlan in the dst_metadata.
vxlan driver will lookup forwarding database with (mac + vni)
for the required remote destination information to forward the
packet.
Changes introduced by this patch:
- allow learning and forwarding database state in vxlan netdev in
COLLECT_METADATA mode. Current behaviour is not changed
by default. tunnel info flag IP_TUNNEL_INFO_BRIDGE is used
to support the new bridge friendly mode.
- A single fdb table hashed by (mac, vni) to allow fdb entries with
multiple vnis in the same fdb table
- rx path already has the vni
- tx path expects a vni in the packet with dst_metadata
- prior to this series, fdb remote_dsts carried remote vni and
the vxlan device carrying the fdb table represented the
source vni. With the vxlan device now representing multiple vnis,
this patch adds a src vni attribute to the fdb entry. The remote
vni already uses NDA_VNI attribute. This patch introduces
NDA_SRC_VNI netlink attribute to represent the src vni in a multi
vni fdb table.
iproute2 example (patched and pruned iproute2 output to just show
relevant fdb entries):
example shows same host mac learnt on two vni's.
before (netdev per vni):
$bridge fdb show | grep "00:02:00:00:00:03"
00:02:00:00:00:03 dev vxlan1001 dst 12.0.0.8 self
00:02:00:00:00:03 dev vxlan1000 dst 12.0.0.8 self
after this patch with collect metadata in bridged mode (single netdev):
$bridge fdb show | grep "00:02:00:00:00:03"
00:02:00:00:00:03 dev vxlan0 src_vni 1001 dst 12.0.0.8 self
00:02:00:00:00:03 dev vxlan0 src_vni 1000 dst 12.0.0.8 self
Signed-off-by: 
Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>