HC2VPP-268: add non-eos MPLS and IP FIB entries

VPP manages separate eos and non-eos forwarding chains,
so non-eos FIB entry is also needed.

Imposing received outgoing label on IP packets
is also required as described in
https://tools.ietf.org/html/draft-ietf-idr-bgp-prefix-sid-07#page-10
and
https://tools.ietf.org/html/draft-ietf-spring-segment-routing-msdc-08#section-4.2.2

Change-Id: Idb91dc44beb64f614f02a95ef0f4b8495c6aeb69
Signed-off-by: Marek Gradzki <mgradzki@cisco.com>

3 files changed, 286 insertions, 122 deletions

diff --git a/bgp/bgp-prefix-sid/src/main/java/io/fd/hc2vpp/bgp/prefix/sid/BgpPrefixSidMplsWriter.java b/bgp/bgp-prefix-sid/src/main/java/io/fd/hc2vpp/bgp/prefix/sid/BgpPrefixSidMplsWriter.java
index 081a63e9a..8de70bfb3 100644
--- a/bgp/bgp-prefix-sid/src/main/java/io/fd/hc2vpp/bgp/prefix/sid/BgpPrefixSidMplsWriter.java
+++ b/bgp/bgp-prefix-sid/src/main/java/io/fd/hc2vpp/bgp/prefix/sid/BgpPrefixSidMplsWriter.java
@@ -16,35 +16,21 @@
 
 package io.fd.hc2vpp.bgp.prefix.sid;
 
-import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
 
-import com.google.common.annotations.VisibleForTesting;
 import com.sun.istack.internal.Nullable;
-import io.fd.hc2vpp.common.translate.util.Ipv4Translator;
 import io.fd.hc2vpp.common.translate.util.JvppReplyConsumer;
 import io.fd.honeycomb.translate.bgp.RouteWriter;
 import io.fd.honeycomb.translate.write.WriteFailedException;
 import io.fd.vpp.jvpp.core.dto.MplsRouteAddDel;
 import io.fd.vpp.jvpp.core.future.FutureJVppCore;
-import java.util.List;
 import javax.annotation.Nonnull;
-import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Address;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.LabelIndexTlv;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.labeled.unicast.routes.LabeledUnicastRoutes;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.OriginatorSrgbTlv;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.labeled.unicast.LabelStack;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.labeled.unicast.routes.list.LabeledUnicastRoute;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.originator.srgb.tlv.SrgbValue;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.path.attributes.attributes.BgpPrefixSid;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.path.attributes.attributes.bgp.prefix.sid.BgpPrefixSidTlvs;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.path.attributes.attributes.bgp.prefix.sid.bgp.prefix.sid.tlvs.BgpPrefixSidTlv;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.BgpRib;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.bgp.rib.Rib;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.bgp.rib.rib.LocRib;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.rib.Tables;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.CNextHop;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.c.next.hop.Ipv4NextHopCase;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -55,13 +41,8 @@ import org.slf4j.LoggerFactory;
  * @see <a href="https://tools.ietf.org/html/draft-ietf-idr-bgp-prefix-sid-07#section-4.1">Receiving BGP-Prefix-SID
  * attribute</a>
  */
-final class BgpPrefixSidMplsWriter implements RouteWriter<LabeledUnicastRoute>, Ipv4Translator, JvppReplyConsumer {
-
-    /**
-     * Constant used by VPP to disable optional parameters of mpls label type.
-     */
-    @VisibleForTesting
-    static final int MPLS_LABEL_INVALID = 0x100000;
+final class BgpPrefixSidMplsWriter
+    implements RouteWriter<LabeledUnicastRoute>, MplsRouteRequestProducer, IpRouteRequestProducer, JvppReplyConsumer {
 
     private static final Logger LOG = LoggerFactory.getLogger(BgpPrefixSidMplsWriter.class);
 
@@ -81,16 +62,20 @@ final class BgpPrefixSidMplsWriter implements RouteWriter<LabeledUnicastRoute>,
     public void create(@Nonnull final InstanceIdentifier<LabeledUnicastRoute> id,
                        @Nullable final LabeledUnicastRoute route)
         throws WriteFailedException.CreateFailedException {
-        final MplsRouteAddDel request = request(route, true);
-        LOG.debug("Translating id={}, route={} to {}", id, route, request);
-        getReplyForCreate(vppApi.mplsRouteAddDel(request).toCompletableFuture(), id, route);
+        LOG.debug("Translating id={}, route={}", id, route);
+        // Compute label based on BGP Prefix SID TLVs and add following VPP FIB entries
+        // (see: https://tools.ietf.org/html/draft-ietf-spring-segment-routing-msdc-08#section-4.2.2):
+        //
+        // 1) non-eos VPP MPLS FIB entry (for MPLS packets with derived label in the middle of label stack)
+        final MplsRouteAddDel mplsRequest = mplsRouteAddDelFor(route, true, LOG);
+        getReplyForCreate(vppApi.mplsRouteAddDel(mplsRequest).toCompletableFuture(), id, route);
 
+        // 2) eos VPP MPLS FIB entry (for MPLS packets with derived label at the end of the label stack)
+        mplsRequest.mrEos = 1;
+        getReplyForCreate(vppApi.mplsRouteAddDel(mplsRequest).toCompletableFuture(), id, route);
 
-        // TODO(HC2VPP-268): except for SWAP EOS label entry, we should also create:
-        // 1) SWAP NON-EOS label
-        // 2) Push label to handle situations when non MPLS packet goes in and its destination is equals to
-        // the prefix that is being announced (in the example from the draft, it is BGP-Prefix-SID originator loopback):
-        // https://tools.ietf.org/html/draft-ietf-spring-segment-routing-msdc-06#section-4.2.2
+        // 3) VPP IP FIB entry (impose received outbound label on IP packets destined to the BGP prefix)
+        getReplyForCreate(vppApi.ipAddDelRoute(ipAddDelRouteFor(route, true)).toCompletableFuture(), id, route);
 
         LOG.debug("VPP FIB updated successfully (added id={}).", id);
     }
@@ -100,7 +85,17 @@ final class BgpPrefixSidMplsWriter implements RouteWriter<LabeledUnicastRoute>,
                        @Nullable final LabeledUnicastRoute route)
         throws WriteFailedException.DeleteFailedException {
         LOG.debug("Removing id={}, route={}", id, route);
-        getReplyForDelete(vppApi.mplsRouteAddDel(request(route, false)).toCompletableFuture(), id);
+        // Remove non-eos VPP MPLS FIB entry:
+        final MplsRouteAddDel mplsRequest = mplsRouteAddDelFor(route, false, LOG);
+        getReplyForDelete(vppApi.mplsRouteAddDel(mplsRequest).toCompletableFuture(), id);
+
+        // Remove eos VPP MPLS FIB entry:
+        mplsRequest.mrEos = 1;
+        getReplyForDelete(vppApi.mplsRouteAddDel(mplsRequest).toCompletableFuture(), id);
+
+        // Remove VPP IP FIB entry:
+        getReplyForDelete(vppApi.ipAddDelRoute(ipAddDelRouteFor(route, false)).toCompletableFuture(), id);
+
         LOG.debug("VPP FIB updated successfully (removed id={}).", id);
     }
 
@@ -113,98 +108,6 @@ final class BgpPrefixSidMplsWriter implements RouteWriter<LabeledUnicastRoute>,
             new UnsupportedOperationException("Operation not supported"));
     }
 
-    private MplsRouteAddDel request(final LabeledUnicastRoute route, boolean isAdd) {
-        final MplsRouteAddDel request = mplsRouteAddDel(isAdd);
-
-
-        translate(route.getAttributes().getCNextHop(), request);
-        translate(route.getAttributes().getBgpPrefixSid(), request);
-        translate(route.getLabelStack(), request);
-
-        request.mrEos = 1;
-        return request;
-    }
-
-    private MplsRouteAddDel mplsRouteAddDel(final boolean isAdd) {
-        final MplsRouteAddDel request = new MplsRouteAddDel();
-        request.mrIsAdd = booleanToByte(isAdd);
-
-        // default values based on inspecting VPP's CLI and make test code
-        request.mrClassifyTableIndex = -1;
-        request.mrNextHopWeight = 1;
-        request.mrNextHopViaLabel = MPLS_LABEL_INVALID;
-        return request;
-    }
-
-    private void translate(@Nonnull final CNextHop cNextHop, @Nonnull final MplsRouteAddDel request) {
-        checkArgument(cNextHop instanceof Ipv4NextHopCase,
-            "only ipv4 next hop is supported, but was %s (cNextHop = %s)", cNextHop, cNextHop);
-        final Ipv4Address nextHop = ((Ipv4NextHopCase) cNextHop).getIpv4NextHop().getGlobal();
-        request.mrNextHop = ipv4AddressNoZoneToArray(nextHop.getValue());
-
-        // We create recursive route. In order to make everything work,
-        // operator needs to manually map next hop address to proper interface.
-        // Either via CLI or HC.
-        //
-        // VPP can't recursively resolve a route that has out labels via a route that does not have out labels.
-        // Implicit null label is trick to get around it (no more labels will be added to the package).
-        // CLI example:
-        //
-        // ip route add <next-hop-ip> via <next-hop-ifc> out-labels 3
-        request.mrNextHopSwIfIndex = -1;
-    }
-
-    private void translate(@Nonnull final BgpPrefixSid bgpPrefixSid, @Nonnull final MplsRouteAddDel request) {
-        Long labelIndex = null;
-        OriginatorSrgbTlv originatorSrgb = null;
-        for (BgpPrefixSidTlvs entry : bgpPrefixSid.getBgpPrefixSidTlvs()) {
-            final BgpPrefixSidTlv tlv = entry.getBgpPrefixSidTlv();
-            if (tlv instanceof LabelIndexTlv) {
-                if (labelIndex != null) {
-                    LOG.warn("        More than one label-index-tlv encountered while parsing bgp-prefix-sid-tlvs: %s."
-                        + "Ignoring all but %s", bgpPrefixSid, labelIndex);
-                } else {
-                    labelIndex = ((LabelIndexTlv) tlv).getLabelIndexTlv();
-                }
-            } else if (tlv instanceof OriginatorSrgbTlv) {
-                if (originatorSrgb != null) {
-                    LOG.warn("More than one originator-srgb-tlv encountered while parsing bgp-prefix-sid-tlvs: %s."
-                        + "Ignoring all but %s", bgpPrefixSid, originatorSrgb);
-                } else {
-                    originatorSrgb = (OriginatorSrgbTlv) tlv;
-                }
-            }
-        }
-
-        // TODO(HC2VPP-272): add support for dynamic (random) label (RFC3107)
-
-        checkArgument(labelIndex != null, "Missing label-index-tlv");
-        // TODO(HC2VPP-272): the originator-srgb-tlv is optional, make SRGB range configurable via netconf (requires writeConfig)
-        checkArgument(originatorSrgb != null, "Missing originator-srgb-tlv");
-        // TODO(HC2VPP-272): add support for more than one SRGB
-        checkArgument(originatorSrgb.getSrgbValue().size() == 1,
-            "Only one SRGB range is currently supported, but more than one was defined: %s", originatorSrgb);
-        // Compute local label based on labelIndex value:
-        final SrgbValue srgbValue = originatorSrgb.getSrgbValue().get(0);
-        final long srgbStart = srgbValue.getBase().getValue();
-        final long localLabel = srgbStart + labelIndex;
-        final long srgbEnd = srgbStart + srgbValue.getRange().getValue();
-        checkArgument(localLabel <= srgbEnd && localLabel >= srgbStart);
-        request.mrLabel = (int) localLabel;
-    }
-
-    private void translate(@Nonnull final List<LabelStack> labelStack, @Nonnull final MplsRouteAddDel request) {
-        final int labelCount = labelStack.size();
-        checkArgument(labelCount == 1, "Single label expected, but labelStack.size()==%s", labelCount);
-        final int label = labelStack.get(0).getLabelValue().getValue().intValue();
-
-        // TODO(HC2VPP-271): add support for special labels, e.g. implicit null (for PHP).
-
-        // swap one label to another
-        request.mrNextHopOutLabelStack = new int[] {label};
-        request.mrNextHopNOutLabels = 1;
-    }
-
     // TODO(HC2VPP-268): add test which checks if ID is serializable
     @Nonnull
     @Override
diff --git a/bgp/bgp-prefix-sid/src/main/java/io/fd/hc2vpp/bgp/prefix/sid/IpRouteRequestProducer.java b/bgp/bgp-prefix-sid/src/main/java/io/fd/hc2vpp/bgp/prefix/sid/IpRouteRequestProducer.java
new file mode 100644
index 000000000..4093a040b
--- /dev/null
+++ b/bgp/bgp-prefix-sid/src/main/java/io/fd/hc2vpp/bgp/prefix/sid/IpRouteRequestProducer.java
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ *
+ * 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 io.fd.hc2vpp.bgp.prefix.sid;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static io.fd.hc2vpp.bgp.prefix.sid.MplsRouteRequestProducer.MPLS_LABEL_INVALID;
+
+import io.fd.hc2vpp.common.translate.util.Ipv4Translator;
+import io.fd.vpp.jvpp.core.dto.IpAddDelRoute;
+import java.util.List;
+import javax.annotation.Nonnull;
+import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.IpPrefix;
+import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Address;
+import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Prefix;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.labeled.unicast.LabelStack;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.labeled.unicast.routes.list.LabeledUnicastRoute;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.CNextHop;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.c.next.hop.Ipv4NextHopCase;
+
+interface IpRouteRequestProducer {
+    /**
+     * Produces {@link IpAddDelRoute} request that imposes MPLS label received via BGP LU on packets
+     * destined to the prefix the label was assigned to.
+     *
+     * @param route BPG LU route received via BGP
+     * @param isAdd determines whether to produce request for adding or removing VPP config
+     * @return jVpp request for updating VPP IP FIB.
+     * @see <a href="https://tools.ietf.org/html/rfc3107">Carrying Label Information in BGP-4</a>
+     * @see <a href="https://tools.ietf.org/html/draft-ietf-idr-bgp-prefix-sid-07#page-10">BGP Prefix SID: programming
+     * outgoing label</a>
+     * @see <a href="https://tools.ietf.org/html/draft-ietf-spring-segment-routing-msdc-08#section-4.2.2">FIB example
+     * for SR in the DC usecase</a>
+     */
+    default IpAddDelRoute ipAddDelRouteFor(@Nonnull final LabeledUnicastRoute route, final boolean isAdd) {
+        final IpAddDelRoute request = Impl.ipAddDelRoute(isAdd);
+        Impl.translate(route.getPrefix(), request);
+        Impl.translate(route.getAttributes().getCNextHop(), request);
+        Impl.translate(route.getLabelStack(), request);
+        return request;
+    }
+
+    final class Impl {
+        private static IpAddDelRoute ipAddDelRoute(final boolean isAdd) {
+            final IpAddDelRoute request = new IpAddDelRoute();
+            request.isAdd = Ipv4Translator.INSTANCE.booleanToByte(isAdd);
+
+            // default values based on inspecting VPP's CLI and make test code
+            request.classifyTableIndex = -1;
+            request.nextHopWeight = 1;
+            request.nextHopViaLabel = MPLS_LABEL_INVALID;
+            return request;
+        }
+
+        private static void translate(@Nonnull final IpPrefix prefix, final IpAddDelRoute request) {
+            // BGP Prefix SID for v6 is not supported
+            final Ipv4Prefix ipv4Prefix = prefix.getIpv4Prefix();
+            checkArgument(ipv4Prefix != null, "Unsupported IpPrefix: %s, ipv4Prefix is missing.", prefix);
+            request.dstAddressLength = Ipv4Translator.INSTANCE.extractPrefix(ipv4Prefix);
+            request.dstAddress = Ipv4Translator.INSTANCE.ipv4AddressPrefixToArray(ipv4Prefix);
+        }
+
+        private static void translate(@Nonnull final CNextHop nextHop, @Nonnull final IpAddDelRoute request) {
+            checkArgument(nextHop instanceof Ipv4NextHopCase, "only ipv4 next hop is supported, but was %s", nextHop);
+
+            final Ipv4Address nextHopAddress = ((Ipv4NextHopCase) nextHop).getIpv4NextHop().getGlobal();
+            request.nextHopAddress = Ipv4Translator.INSTANCE.ipv4AddressNoZoneToArray(nextHopAddress.getValue());
+
+            // We create recursive route. In order to make everything work,
+            // operator needs to manually map next hop address to proper interface.
+            // Either via CLI or HC.
+            //
+            // VPP can't recursively resolve a route that has out labels via a route that does not have out labels.
+            // Implicit null(3) label is trick to get around it (no more labels will be added to the package).
+            // CLI example:
+            //
+            // ip route add <next-hop-prefix> via <next-hop-ifc> out-labels 3
+            request.nextHopSwIfIndex = -1;
+        }
+
+        private static void translate(@Nonnull final List<LabelStack> labelStack,
+                                      @Nonnull final IpAddDelRoute request) {
+            // It is quite possible we could support multiple labels here, but it was never tested
+            // so it is not supported currently.
+            final int labelCount = labelStack.size();
+            checkArgument(labelCount == 1, "Single label expected, but labelStack.size()==%s", labelCount);
+            final int label = labelStack.get(0).getLabelValue().getValue().intValue();
+
+            // TODO(HC2VPP-271): add support for special labels, e.g. implicit null (for PHP).
+
+            // Push label received via BGP on packets destined to the prefix it was assigned to:
+            request.nextHopOutLabelStack = new int[] {label};
+            request.nextHopNOutLabels = 1;
+        }
+    }
+}
diff --git a/bgp/bgp-prefix-sid/src/main/java/io/fd/hc2vpp/bgp/prefix/sid/MplsRouteRequestProducer.java b/bgp/bgp-prefix-sid/src/main/java/io/fd/hc2vpp/bgp/prefix/sid/MplsRouteRequestProducer.java
new file mode 100644
index 000000000..659cb991f
--- /dev/null
+++ b/bgp/bgp-prefix-sid/src/main/java/io/fd/hc2vpp/bgp/prefix/sid/MplsRouteRequestProducer.java
@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ *
+ * 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 io.fd.hc2vpp.bgp.prefix.sid;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+import io.fd.hc2vpp.common.translate.util.Ipv4Translator;
+import io.fd.vpp.jvpp.core.dto.MplsRouteAddDel;
+import java.util.List;
+import javax.annotation.Nonnull;
+import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Address;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.LabelIndexTlv;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.OriginatorSrgbTlv;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.labeled.unicast.LabelStack;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.labeled.unicast.routes.list.LabeledUnicastRoute;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.labeled.unicast.rev150525.originator.srgb.tlv.SrgbValue;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.path.attributes.attributes.BgpPrefixSid;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.path.attributes.attributes.bgp.prefix.sid.BgpPrefixSidTlvs;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.path.attributes.attributes.bgp.prefix.sid.bgp.prefix.sid.tlvs.BgpPrefixSidTlv;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.CNextHop;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.c.next.hop.Ipv4NextHopCase;
+import org.slf4j.Logger;
+
+interface MplsRouteRequestProducer extends Ipv4Translator {
+    /**
+     * Constant used by VPP to disable optional parameters of mpls label type.
+     */
+    int MPLS_LABEL_INVALID = 0x100000;
+
+    /**
+     * Produces {@link MplsRouteAddDel} request for derived local label entry
+     * that swaps it for the received outbound label.
+     *
+     * @param route BPG LU route received via BGP
+     * @param isAdd determines whether to produce request for adding or removing VPP config
+     * @return jVpp request for updating VPP MPLS FIB.
+     * @see <a href="https://tools.ietf.org/html/rfc3107">Carrying Label Information in BGP-4</a>
+     * @see <a href="https://tools.ietf.org/html/draft-ietf-idr-bgp-prefix-sid-07#page-10">BGP Prefix SID: programming
+     * outgoing label</a>
+     * @see <a href="https://tools.ietf.org/html/draft-ietf-spring-segment-routing-msdc-08#section-4.2.2">FIB example
+     * for SR in the DC usecase</a>
+     */
+    default MplsRouteAddDel mplsRouteAddDelFor(@Nonnull final LabeledUnicastRoute route, final boolean isAdd,
+                                               @Nonnull final Logger logger) {
+        final MplsRouteAddDel request = Impl.mplsRouteAddDel(isAdd);
+        Impl.translate(route.getAttributes().getCNextHop(), request);
+        Impl.translate(route.getAttributes().getBgpPrefixSid(), request, logger);
+        Impl.translate(route.getLabelStack(), request);
+        return request;
+    }
+
+    final class Impl implements Ipv4Translator {
+        private static MplsRouteAddDel mplsRouteAddDel(final boolean isAdd) {
+            final MplsRouteAddDel request = new MplsRouteAddDel();
+            request.mrIsAdd = Ipv4Translator.INSTANCE.booleanToByte(isAdd);
+
+            // default values based on inspecting VPP's CLI and make test code
+            request.mrClassifyTableIndex = -1;
+            request.mrNextHopWeight = 1;
+            request.mrNextHopViaLabel = MPLS_LABEL_INVALID;
+            return request;
+        }
+
+        private static void translate(@Nonnull final CNextHop nextHop, @Nonnull final MplsRouteAddDel request) {
+            checkArgument(nextHop instanceof Ipv4NextHopCase, "only ipv4 next hop is supported, but was %s", nextHop);
+            final Ipv4Address nextHopAddress = ((Ipv4NextHopCase) nextHop).getIpv4NextHop().getGlobal();
+            request.mrNextHop = Ipv4Translator.INSTANCE.ipv4AddressNoZoneToArray(nextHopAddress.getValue());
+
+            // We create recursive route. In order to make everything work,
+            // operator needs to manually map next hop address to proper interface.
+            // Either via CLI or HC.
+            //
+            // VPP can't recursively resolve a route that has out labels via a route that does not have out labels.
+            // Implicit null(3) label is trick to get around it (no more labels will be added to the package).
+            // CLI example:
+            //
+            // ip route add <next-hop-prefix> via <next-hop-ifc> out-labels 3
+            request.mrNextHopSwIfIndex = -1;
+        }
+
+        private static void translate(@Nonnull final BgpPrefixSid bgpPrefixSid, @Nonnull final MplsRouteAddDel request,
+                                      @Nonnull final Logger logger) {
+            Long labelIndex = null;
+            OriginatorSrgbTlv originatorSrgb = null;
+            for (BgpPrefixSidTlvs entry : bgpPrefixSid.getBgpPrefixSidTlvs()) {
+                final BgpPrefixSidTlv tlv = entry.getBgpPrefixSidTlv();
+                if (tlv instanceof LabelIndexTlv) {
+                    if (labelIndex != null) {
+                        logger.warn("More than one label-index-tlv encountered while parsing bgp-prefix-sid-tlvs: %s."
+                            + "Ignoring all but %s", bgpPrefixSid, labelIndex);
+                    } else {
+                        labelIndex = ((LabelIndexTlv) tlv).getLabelIndexTlv();
+                    }
+                } else if (tlv instanceof OriginatorSrgbTlv) {
+                    if (originatorSrgb != null) {
+                        logger
+                            .warn("More than one originator-srgb-tlv encountered while parsing bgp-prefix-sid-tlvs: %s."
+                                + "Ignoring all but %s", bgpPrefixSid, originatorSrgb);
+                    } else {
+                        originatorSrgb = (OriginatorSrgbTlv) tlv;
+                    }
+                }
+            }
+
+            // TODO(HC2VPP-272): add support for dynamic (random) label (RFC3107)
+
+            checkArgument(labelIndex != null, "Missing label-index-tlv");
+            // TODO(HC2VPP-272): the originator-srgb-tlv is optional,
+            // make SRGB range configurable via netconf (requires writeConfig)
+            checkArgument(originatorSrgb != null, "Missing originator-srgb-tlv");
+            // TODO(HC2VPP-272): add support for more than one SRGB
+            checkArgument(originatorSrgb.getSrgbValue().size() == 1,
+                "Only one SRGB range is currently supported, but more than one was defined: %s", originatorSrgb);
+            // Compute local label based on labelIndex value:
+            final SrgbValue srgbValue = originatorSrgb.getSrgbValue().get(0);
+            final long srgbStart = srgbValue.getBase().getValue();
+            final long localLabel = srgbStart + labelIndex;
+            final long srgbEnd = srgbStart + srgbValue.getRange().getValue();
+            checkArgument(localLabel <= srgbEnd && localLabel >= srgbStart);
+            request.mrLabel = (int) localLabel;
+        }
+
+        private static void translate(@Nonnull final List<LabelStack> labelStack,
+                                      @Nonnull final MplsRouteAddDel request) {
+            // It is quite possible we could support multiple labels here, but it was never tested
+            // so it is not supported currently.
+            final int labelCount = labelStack.size();
+            checkArgument(labelCount == 1, "Single label expected, but labelStack.size()==%s", labelCount);
+            final int label = labelStack.get(0).getLabelValue().getValue().intValue();
+
+            // TODO(HC2VPP-271): add support for special labels, e.g. implicit null (for PHP).
+
+            // swap one label to another
+            request.mrNextHopOutLabelStack = new int[] {label};
+            request.mrNextHopNOutLabels = 1;
+        }
+    }
+}