From 8d59c9195a509b0a33e4c67077f077b7bb73c6dc Mon Sep 17 00:00:00 2001
From: Christopher Dziomba <christopher.dziomba@telekom.de>
Date: Tue, 7 Nov 2023 11:51:38 +0100
Subject: [PATCH 1/2] Generate Bridge MAC from Underlay RMAC

---
 pkg/nl/create.go | 13 ++++++++++++-
 pkg/nl/layer2.go |  2 +-
 pkg/nl/layer3.go |  2 +-
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/pkg/nl/create.go b/pkg/nl/create.go
index 86f90b9c..f4f11385 100644
--- a/pkg/nl/create.go
+++ b/pkg/nl/create.go
@@ -36,7 +36,7 @@ func (n *NetlinkManager) createVRF(vrfName string, table int) (*netlink.Vrf, err
 	return &netlinkVrf, nil
 }
 
-func (n *NetlinkManager) createBridge(bridgeName string, macAddress *net.HardwareAddr, masterIdx, mtu int) (*netlink.Bridge, error) {
+func (n *NetlinkManager) createBridge(bridgeName string, macAddress *net.HardwareAddr, masterIdx, mtu int, underlayRMAC bool) (*netlink.Bridge, error) {
 	netlinkBridge := netlink.Bridge{
 		LinkAttrs: netlink.LinkAttrs{
 			Name: bridgeName,
@@ -48,6 +48,17 @@ func (n *NetlinkManager) createBridge(bridgeName string, macAddress *net.Hardwar
 	}
 	if macAddress != nil {
 		netlinkBridge.LinkAttrs.HardwareAddr = *macAddress
+	} else if underlayRMAC {
+		_, vxlanIP, err := getInterfaceAndIP(underlayLoopback)
+		if err != nil {
+			return nil, err
+		}
+
+		generatedMac, err := generateMAC(vxlanIP)
+		if err != nil {
+			return nil, err
+		}
+		netlinkBridge.LinkAttrs.HardwareAddr = generatedMac
 	}
 
 	if err := netlink.LinkAdd(&netlinkBridge); err != nil {
diff --git a/pkg/nl/layer2.go b/pkg/nl/layer2.go
index f5d8258d..fb96e7b7 100644
--- a/pkg/nl/layer2.go
+++ b/pkg/nl/layer2.go
@@ -100,7 +100,7 @@ func (n *NetlinkManager) CreateL2(info *Layer2Information) error {
 }
 
 func (n *NetlinkManager) setupBridge(info *Layer2Information, masterIdx int) (*netlink.Bridge, error) {
-	bridge, err := n.createBridge(fmt.Sprintf("%s%d", layer2Prefix, info.VlanID), info.AnycastMAC, masterIdx, info.MTU)
+	bridge, err := n.createBridge(fmt.Sprintf("%s%d", layer2Prefix, info.VlanID), info.AnycastMAC, masterIdx, info.MTU, false)
 	if err != nil {
 		return nil, err
 	}
diff --git a/pkg/nl/layer3.go b/pkg/nl/layer3.go
index e9896402..3574d9ab 100644
--- a/pkg/nl/layer3.go
+++ b/pkg/nl/layer3.go
@@ -39,7 +39,7 @@ func (n *NetlinkManager) CreateL3(info VRFInformation) error {
 		return err
 	}
 
-	bridge, err := n.createBridge(bridgePrefix+info.Name, nil, vrf.Attrs().Index, defaultMtu)
+	bridge, err := n.createBridge(bridgePrefix+info.Name, nil, vrf.Attrs().Index, defaultMtu, true)
 	if err != nil {
 		return err
 	}

From 58fda8a5ce398f8271e7eb729e103903584cf605 Mon Sep 17 00:00:00 2001
From: Christopher Dziomba <christopher.dziomba@telekom.de>
Date: Tue, 7 Nov 2023 12:08:26 +0100
Subject: [PATCH 2/2] Rename function to getUnderlayInterfaceAndIP and remove
 params

---
 pkg/nl/create.go  | 10 +++++-----
 pkg/nl/manager.go |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/pkg/nl/create.go b/pkg/nl/create.go
index f4f11385..42f40dbd 100644
--- a/pkg/nl/create.go
+++ b/pkg/nl/create.go
@@ -49,7 +49,7 @@ func (n *NetlinkManager) createBridge(bridgeName string, macAddress *net.Hardwar
 	if macAddress != nil {
 		netlinkBridge.LinkAttrs.HardwareAddr = *macAddress
 	} else if underlayRMAC {
-		_, vxlanIP, err := getInterfaceAndIP(underlayLoopback)
+		_, vxlanIP, err := getUnderlayInterfaceAndIP()
 		if err != nil {
 			return nil, err
 		}
@@ -72,7 +72,7 @@ func (n *NetlinkManager) createBridge(bridgeName string, macAddress *net.Hardwar
 }
 
 func (n *NetlinkManager) createVXLAN(vxlanName string, bridgeIdx, vni, mtu int, hairpin, neighSuppression bool) (*netlink.Vxlan, error) {
-	vxlanIf, vxlanIP, err := getInterfaceAndIP(underlayLoopback)
+	vxlanIf, vxlanIP, err := getUnderlayInterfaceAndIP()
 	if err != nil {
 		return nil, err
 	}
@@ -166,7 +166,7 @@ func (*NetlinkManager) setUp(intfName string) error {
 }
 
 func generateUnderlayMAC() (net.HardwareAddr, error) {
-	_, vxlanIP, err := getInterfaceAndIP(underlayLoopback)
+	_, vxlanIP, err := getUnderlayInterfaceAndIP()
 	if err != nil {
 		return nil, err
 	}
@@ -178,8 +178,8 @@ func generateUnderlayMAC() (net.HardwareAddr, error) {
 	return generatedMac, nil
 }
 
-func getInterfaceAndIP(name string) (int, net.IP, error) {
-	dummy := netlink.Dummy{LinkAttrs: netlink.LinkAttrs{Name: name}}
+func getUnderlayInterfaceAndIP() (int, net.IP, error) {
+	dummy := netlink.Dummy{LinkAttrs: netlink.LinkAttrs{Name: underlayLoopback}}
 
 	addresses, err := netlink.AddrList(&dummy, netlink.FAMILY_V4)
 	if err != nil {
diff --git a/pkg/nl/manager.go b/pkg/nl/manager.go
index 7fcd2dcb..8873b742 100644
--- a/pkg/nl/manager.go
+++ b/pkg/nl/manager.go
@@ -29,6 +29,6 @@ type NetlinkManager struct {
 }
 
 func (*NetlinkManager) GetUnderlayIP() (net.IP, error) {
-	_, ip, err := getInterfaceAndIP(underlayLoopback)
+	_, ip, err := getUnderlayInterfaceAndIP()
 	return ip, err
 }