Add TranslateUplinkAddrMaskTo64 option only for non LL /128

This patch transforms the UplinkSubnetMask option to TranslateUplinkAddrMaskTo64
and restricts it to only apply to non linklocal v6 addresses read on the
uplink interface, and that have a /128 prefix

With the previous implementation we were trying to program VPP with LL /64
addresses which was returning errors.

Also this patch makes it so that vpp-manager will error out if it fails
programming VPP with an address so that we notice such errors

Signed-off-by: Nathan Skrzypczak <nathan.skrzypczak@gmail.com>

Author: sknat

config/config.go

@@ -318,9 +318,12 @@ type CalicoVppDebugConfigType struct {
 	// get the v6 link local address from the tap created in linux
 	// to replace the uplink before giving up.
 	FetchV6LLntries *uint32 `json:"fetchV6LLntries,omitempty"`
-	// UplinkSubnetMask is the subnet mask we configure on the uplink
-	// regardless of the source netmask from Linux interface.
-	UplinkSubnetMask *uint16 `json:"uplinkSubnetMask,omitempty"`
+	// TranslateUplinkAddrMaskTo64 if set will convert all the non link local
+	// addresses read on the uplink interface that are [::ipv6]/128 to be [::ipv6]/64
+	// this is enabled by default as VPP currently lacks the implementation of
+	// getting the prefix over router advertisements with option L and !A
+	// proper implementation will come in a later VPP patch.
+	TranslateUplinkAddrMaskTo64 *bool `json:"translateUplinkAddrMaskTo64,omitempty"`
 }
 
 func (cfg *CalicoVppDebugConfigType) String() string {
@@ -341,11 +344,8 @@ func (cfg *CalicoVppDebugConfigType) Validate() (err error) {
 	if cfg.EnableUdevNetNameRules == nil {
 		cfg.EnableUdevNetNameRules = &True
 	}
-	var uplinkSubnetMask uint16 = 64
-	if cfg.UplinkSubnetMask == nil {
-		cfg.UplinkSubnetMask = &uplinkSubnetMask
-	} else if *cfg.UplinkSubnetMask == 0 || *cfg.UplinkSubnetMask > 128 {
-		return errors.Errorf("uplinkSubnetMask must be in [1,128]")
+	if cfg.TranslateUplinkAddrMaskTo64 == nil {
+		cfg.TranslateUplinkAddrMaskTo64 = &True
 	}
 	var v uint32 = 5
 	if cfg.FetchV6LLntries == nil {

vpp-manager/vpp_runner.go

@@ -50,17 +50,23 @@ type VppRunner struct {
 	uplinkDriver []uplink.UplinkDriver
 }
 
+// getUplinkAddressWithMask will update the mask of an ipv6 address
+// and set it from /128 to /64 if the option 'TranslateUplinkAddrMaskTo64' is set
+// this will not update Link-local addresses
 func getUplinkAddressWithMask(addr *net.IPNet) *net.IPNet {
-	if addr == nil || addr.IP == nil || addr.IP.To4() != nil {
+	if addr == nil || addr.IP == nil || addr.IP.To4() != nil || addr.IP.IsLinkLocalUnicast() {
 		return addr
 	}
-	subnetMask := uint16(64)
-	if config.GetCalicoVppDebug().UplinkSubnetMask != nil {
-		subnetMask = *config.GetCalicoVppDebug().UplinkSubnetMask
+	if !*config.GetCalicoVppDebug().TranslateUplinkAddrMaskTo64 {
+		return addr
+	}
+	ones, _ := addr.Mask.Size()
+	if ones != 128 {
+		return addr
 	}
 	return &net.IPNet{
 		IP:   addr.IP,
-		Mask: net.CIDRMask(int(subnetMask), 128),
+		Mask: net.CIDRMask(64, 128),
 	}
 }
 
@@ -521,10 +527,10 @@ func (v *VppRunner) configureVppUplinkInterface(
 	}
 
 	for _, addr := range ifState.GetAddresses() {
-		log.Infof("Adding address %s to uplink interface", addr.String())
+		log.Infof("Adding address %s to uplink interface", getUplinkAddressWithMask(addr.IPNet).String())
 		err = v.vpp.AddInterfaceAddress(ifSpec.SwIfIndex, getUplinkAddressWithMask(addr.IPNet))
 		if err != nil {
-			log.Errorf("Error adding address to uplink interface: %v", err)
+			return errors.Wrapf(err, "Error adding address %s to uplink interface", getUplinkAddressWithMask(addr.IPNet))
 		}
 	}
 	for _, route := range ifState.GetRoutes() {
@@ -657,13 +663,13 @@ func (v *VppRunner) configureVppUplinkInterface(
 	}
 
 	if ifState.IPv6LinkLocal.IPNet != nil {
-		err = v.vpp.AddInterfaceAddress(ifSpec.SwIfIndex, getUplinkAddressWithMask(common.FullyQualified(ifState.IPv6LinkLocal.IP)))
+		err = v.vpp.AddInterfaceAddress(ifSpec.SwIfIndex, common.FullyQualified(ifState.IPv6LinkLocal.IP))
 		if err != nil {
-			log.Errorf("Error adding address to uplink interface: %v", err)
+			return errors.Wrapf(err, "Error adding address %s to uplink interface: %d", common.FullyQualified(ifState.IPv6LinkLocal.IP), ifSpec.SwIfIndex)
 		}
 		err = v.vpp.EnableIP6NdProxy(tapSwIfIndex, ifState.IPv6LinkLocal.IP)
 		if err != nil {
-			log.Errorf("Error configuring nd proxy for address %s: %v", ifState.IPv6LinkLocal.IP.String(), err)
+			return errors.Wrapf(err, "Error configuring nd proxy for address %s", ifState.IPv6LinkLocal.IP.String())
 		}
 	}