feat: dummy linux interface and existing IPs

plugins/linux/ifplugin/descriptor/interface.go

@@ -15,6 +15,7 @@
 package descriptor
 
 import (
+	"fmt"
 	"io/ioutil"
 	"net"
 	"path/filepath"
@@ -107,6 +108,10 @@ var (
 	// EXISTING interface.
 	ErrExistingWithNamespace = errors.New("EXISTING interface defined with namespace")
 
+	// ErrExistingIpWithNetalloc is returned when netalloc and EXISTING-IP features are combined,
+	// which is currently not supported.
+	ErrExistingIpWithNetalloc = errors.New("it is not supported to reference EXISTING-IP via netalloc")
+
 	// ErrInvalidIPWithMask is returned when address is invalid or mask is missing
 	ErrInvalidIPWithMask = errors.New("IP with mask is not valid")
 
@@ -281,6 +286,16 @@ func (d *InterfaceDescriptor) Validate(key string, linuxIf *interfaces.Interface
 		if linuxIf.GetNamespace() != nil {
 			return kvs.NewInvalidValueError(ErrExistingWithNamespace, "namespace")
 		}
+		// Currently it is not supported to combine netalloc with existing IP.
+		if linuxIf.GetLinkOnly() {
+			for i, ipAddr := range linuxIf.GetIpAddresses() {
+				_, hasAllocDep := d.addrAlloc.GetAddressAllocDep(ipAddr, linuxIf.Name, "")
+				if hasAllocDep {
+					return kvs.NewInvalidValueError(ErrExistingIpWithNetalloc,
+						"type", "link_only", fmt.Sprintf("ip_addresses[%d]", i))
+				}
+			}
+		}
 	case interfaces.Interface_LOOPBACK:
 		if linuxIf.GetLink() != nil {
 			return kvs.NewInvalidValueError(ErrInterfaceReferenceMismatch, "link")
@@ -357,6 +372,8 @@ func (d *InterfaceDescriptor) Create(key string, linuxIf *interfaces.Interface)
 		metadata, err = getMetadata(linuxIf)
 	case interfaces.Interface_VRF_DEVICE:
 		metadata, err = d.createVRF(nsCtx, linuxIf)
+	case interfaces.Interface_DUMMY:
+		metadata, err = d.createDummyIf(nsCtx, linuxIf)
 	default:
 		return nil, ErrUnsupportedLinuxInterfaceType
 	}
@@ -455,6 +472,8 @@ func (d *InterfaceDescriptor) Delete(key string, linuxIf *interfaces.Interface,
 		return nil
 	case interfaces.Interface_VRF_DEVICE:
 		return d.deleteVRF(linuxIf)
+	case interfaces.Interface_DUMMY:
+		return d.deleteDummyIf(linuxIf)
 	}
 
 	err = ErrUnsupportedLinuxInterfaceType
@@ -635,12 +654,20 @@ func (d *InterfaceDescriptor) DerivedValues(key string, linuxIf *interfaces.Inte
 			Value: &prototypes.Empty{},
 		})
 	}
-	if !linuxIf.GetLinkOnly() {
+	if !linuxIf.GetLinkOnly() || linuxIf.GetType() == interfaces.Interface_EXISTING {
+		var ipSource netalloc_api.IPAddressSource
+		var hostName string
+		if linuxIf.GetLinkOnly() { // interface type = EXISTING
+			ipSource = netalloc_api.IPAddressSource_EXISTING
+			hostName = getHostIfName(linuxIf)
+		} else {
+			ipSource = netalloc_api.IPAddressSource_STATIC
+		}
 		// IP addresses
 		for _, ipAddr := range linuxIf.IpAddresses {
 			derValues = append(derValues, kvs.KeyValuePair{
 				Key:   interfaces.InterfaceAddressKey(
-					linuxIf.Name, ipAddr, linuxIf.VrfMasterInterface, netalloc_api.IPAddressSource_STATIC),
+					linuxIf.Name, ipAddr, linuxIf.VrfMasterInterface, hostName, ipSource),
 				Value: &prototypes.Empty{},
 			})
 		}

plugins/linux/ifplugin/descriptor/interface_address.go

@@ -41,7 +41,8 @@ const (
 	DisableIPv6SysctlTemplate = "net.ipv6.conf.%s.disable_ipv6"
 
 	// dependency labels
-	interfaceVrfDep = "interface-assigned-to-vrf"
+	interfaceVrfDep  = "interface-assigned-to-vrf"
+	interfaceAddrDep = "address-assigned-to-interface"
 )
 
 // InterfaceAddressDescriptor (un)assigns IP address to/from Linux interface.
@@ -81,17 +82,19 @@ func (d *InterfaceAddressDescriptor) SetInterfaceIndex(intfIndex ifaceidx.LinuxI
 }
 
 // IsInterfaceAddressKey returns true if the key represents assignment of an IP address
-// to a Linux interface (that needs to be applied). KVs representing addresses
-// already allocated from netalloc plugin are excluded.
+// to a Linux interface (that needs to be applied or is expected to exist).
+// KVs representing addresses already allocated from netalloc plugin are excluded.
 func (d *InterfaceAddressDescriptor) IsInterfaceAddressKey(key string) bool {
-	_, _, _, source, _, isAddrKey := interfaces.ParseInterfaceAddressKey(key)
+	_, _, _, _, source, _, isAddrKey := interfaces.ParseInterfaceAddressKey(key)
 	return isAddrKey &&
-		(source == netalloc_api.IPAddressSource_STATIC || source == netalloc_api.IPAddressSource_ALLOC_REF)
+		(source == netalloc_api.IPAddressSource_STATIC ||
+			source == netalloc_api.IPAddressSource_ALLOC_REF ||
+			source == netalloc_api.IPAddressSource_EXISTING)
 }
 
 // Validate validates IP address to be assigned to an interface.
 func (d *InterfaceAddressDescriptor) Validate(key string, emptyVal proto.Message) (err error) {
-	iface, addr, _, _, invalidKey, _ := interfaces.ParseInterfaceAddressKey(key)
+	iface, addr, _, _, _, invalidKey, _ := interfaces.ParseInterfaceAddressKey(key)
 	if invalidKey {
 		return errors.New("invalid key")
 	}
@@ -101,7 +104,11 @@ func (d *InterfaceAddressDescriptor) Validate(key string, emptyVal proto.Message
 
 // Create assigns IP address to an interface.
 func (d *InterfaceAddressDescriptor) Create(key string, emptyVal proto.Message) (metadata kvs.Metadata, err error) {
-	iface, addr, _, _, _, _ := interfaces.ParseInterfaceAddressKey(key)
+	iface, addr, _, _, source, _, _ := interfaces.ParseInterfaceAddressKey(key)
+	if source == netalloc_api.IPAddressSource_EXISTING {
+		// already exists, nothing to do
+		return nil, nil
+	}
 
 	ifMeta, found := d.intfIndex.LookupByName(iface)
 	if !found {
@@ -160,7 +167,11 @@ func (d *InterfaceAddressDescriptor) Create(key string, emptyVal proto.Message)
 
 // Delete unassigns IP address from an interface.
 func (d *InterfaceAddressDescriptor) Delete(key string, emptyVal proto.Message, metadata kvs.Metadata) (err error) {
-	iface, addr, _, _, _, _ := interfaces.ParseInterfaceAddressKey(key)
+	iface, addr, _, _, source, _, _ := interfaces.ParseInterfaceAddressKey(key)
+	if source == netalloc_api.IPAddressSource_EXISTING {
+		// already existed before Create, nothing to do
+		return nil
+	}
 
 	ifMeta, found := d.intfIndex.LookupByName(iface)
 	if !found {
@@ -197,13 +208,19 @@ func (d *InterfaceAddressDescriptor) Delete(key string, emptyVal proto.Message,
 
 // Dependencies mentions (non-default) VRF and a potential allocation of the IP address as dependencies.
 func (d *InterfaceAddressDescriptor) Dependencies(key string, emptyVal proto.Message) (deps []kvs.Dependency) {
-	iface, addr, vrf, _, _, _ := interfaces.ParseInterfaceAddressKey(key)
+	iface, addr, vrf, hostName, source, _, _ := interfaces.ParseInterfaceAddressKey(key)
 	if vrf != "" {
 		deps = append(deps, kvs.Dependency{
 			Label: interfaceVrfDep,
 			Key:   interfaces.InterfaceVrfKey(iface, vrf),
 		})
 	}
+	if source == netalloc_api.IPAddressSource_EXISTING {
+		deps = append(deps, kvs.Dependency{
+			Label: interfaceAddrDep,
+			Key:   interfaces.InterfaceHostNameWithAddrKey(hostName, addr),
+		})
+	}
 	allocDep, hasAllocDep := d.addrAlloc.GetAddressAllocDep(addr, iface, "")
 	if hasAllocDep {
 		deps = append(deps, allocDep)

plugins/linux/ifplugin/descriptor/interface_dummy.go

@@ -0,0 +1,77 @@
+// Copyright (c) 2020 Pantheon.tech
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at:
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package descriptor
+
+import (
+	"github.com/pkg/errors"
+	"go.ligato.io/vpp-agent/v3/plugins/linux/ifplugin/linuxcalls"
+
+	"go.ligato.io/vpp-agent/v3/plugins/linux/ifplugin/ifaceidx"
+	nslinuxcalls "go.ligato.io/vpp-agent/v3/plugins/linux/nsplugin/linuxcalls"
+	interfaces "go.ligato.io/vpp-agent/v3/proto/ligato/linux/interfaces"
+)
+
+// createDummyIf creates dummy interface.
+func (d *InterfaceDescriptor) createDummyIf(
+	nsCtx nslinuxcalls.NamespaceMgmtCtx, linuxIf *interfaces.Interface,
+) (md *ifaceidx.LinuxIfMetadata, err error) {
+	hostName := getHostIfName(linuxIf)
+	agentPrefix := d.serviceLabel.GetAgentPrefix()
+
+	// move to the namespace with the interface
+	revert, err := d.nsPlugin.SwitchToNamespace(nsCtx, linuxIf.Namespace)
+	if err != nil {
+		d.log.Error("switch to namespace failed:", err)
+		return nil, err
+	}
+	defer revert()
+
+	// create a new Dummy interface
+	err = d.ifHandler.AddDummyInterface(hostName)
+	if err != nil {
+		return nil, errors.WithMessagef(err,
+			"failed to create dummy interface %s", hostName)
+	}
+
+	// add alias
+	err = d.ifHandler.SetInterfaceAlias(hostName, agentPrefix+linuxcalls.GetDummyIfAlias(linuxIf))
+	if err != nil {
+		return nil, errors.WithMessagef(err,
+			"error setting alias for Dummy interface %s", hostName)
+	}
+
+	// build metadata
+	link, err := d.ifHandler.GetLinkByName(hostName)
+	if err != nil {
+		return nil, errors.WithMessagef(err, "error getting link %s", hostName)
+	}
+
+	return &ifaceidx.LinuxIfMetadata{
+		Namespace:    linuxIf.Namespace,
+		LinuxIfIndex: link.Attrs().Index,
+		HostIfName:   hostName,
+	}, nil
+}
+
+// deleteDummyIf removes dummy interface.
+func (d *InterfaceDescriptor) deleteDummyIf(linuxIf *interfaces.Interface) error {
+	hostName := getHostIfName(linuxIf)
+	err := d.ifHandler.DeleteInterface(hostName)
+	if err != nil {
+		d.log.Error(err)
+		return err
+	}
+	return nil
+}