Drop using BNG attachment IDs in favor or dynamically allocated line IDs
The current implementation of BngProgrammable for fabric.p4 uses
attachment IDs as line IDs, thus forcing apps such as bngc to be aware
of such implementation detail and to manage the allocation of such IDs.
Unfortunately, allocation of IDs is dependent on the device (P4 program)
implementation (e.g., line counter size), and so it should not be left
to apps.
This patch removes the need for attachment IDs at all and instead relies
on a driver-level service to dynamically allocate line IDs based on the
attachment attributes (currently s-tag, c-tag, mac address).
The current implementation of the allocation logic is a trivial one,
i.e. non-distributed and non-optimized.
Change-Id: Ie960936ee750cf565b8de41370085ecf9d49e931
(cherry picked from commit 6aa2a6ea743e8104ee3c62acb7d26acbd1452614)
diff --git a/pipelines/fabric/impl/src/main/java/org/onosproject/pipelines/fabric/impl/behaviour/bng/FabricBngLineIdAllocator.java b/pipelines/fabric/impl/src/main/java/org/onosproject/pipelines/fabric/impl/behaviour/bng/FabricBngLineIdAllocator.java
new file mode 100644
index 0000000..624df91
--- /dev/null
+++ b/pipelines/fabric/impl/src/main/java/org/onosproject/pipelines/fabric/impl/behaviour/bng/FabricBngLineIdAllocator.java
@@ -0,0 +1,138 @@
+/*
+ * Copyright 2019-present Open Networking Foundation
+ *
+ * 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 org.onosproject.pipelines.fabric.impl.behaviour.bng;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.base.Objects;
+import org.onlab.packet.MacAddress;
+import org.onlab.packet.VlanId;
+import org.onosproject.net.behaviour.BngProgrammable;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * An allocator of line IDs from a fixed range/pool. Used to map attachments to
+ * IDs for counters and other indirect P4 resources.
+ * <p>
+ * An implementation of this interface should use the {@link Handle} class to
+ * uniquely identify attachments and determine whether an ID has already been
+ * allocated or not.
+ */
+public interface FabricBngLineIdAllocator {
+
+ /**
+ * Returns a new ID for the given attachment. The implementation is expected
+ * to be idempotent, i.e., if an ID was previously allocated, then no new
+ * IDs should be allocated but the previous one should be returned.
+ *
+ * @param attachment the attachment instance
+ * @return the ID
+ * @throws IdExhaustedException if all IDs are currently allocated.
+ */
+ long allocate(BngProgrammable.Attachment attachment) throws IdExhaustedException;
+
+ /**
+ * Releases any ID previously allocated for the given attachment. If one was
+ * not allocated, calling this method should be a no-op.
+ *
+ * @param attachment the attachment instance
+ */
+ void release(BngProgrammable.Attachment attachment);
+
+ /**
+ * Releases the given ID, if allocated, otherwise calling this method should
+ * be a no-op.
+ *
+ * @param id the ID to release
+ */
+ void release(long id);
+
+ /**
+ * Returns the maximum number of IDs that can be allocated, independently of
+ * the current state.
+ *
+ * @return maximum number of IDs
+ */
+ long size();
+
+ /**
+ * Returns the number of currently available IDs that can be allocated for
+ * new attachments.
+ *
+ * @return free ID count
+ */
+ long freeCount();
+
+ /**
+ * Returns the number of currently allocated IDs.
+ *
+ * @return allocated ID count
+ */
+ long allocatedCount();
+
+ /**
+ * An identifier of an attachment in the scope of the same instance of a
+ * {@link FabricBngLineIdAllocator}.
+ */
+ class Handle {
+
+ private final VlanId stag;
+ private final VlanId ctag;
+ private final MacAddress macAddress;
+
+ public Handle(BngProgrammable.Attachment attachment) {
+ this.stag = checkNotNull(attachment.sTag());
+ this.ctag = checkNotNull(attachment.cTag());
+ this.macAddress = checkNotNull(attachment.macAddress());
+ }
+
+ @Override
+ public boolean equals(Object o) {
+ if (this == o) {
+ return true;
+ }
+ if (o == null || getClass() != o.getClass()) {
+ return false;
+ }
+ final Handle that = (Handle) o;
+ return Objects.equal(stag, that.stag) &&
+ Objects.equal(ctag, that.ctag) &&
+ Objects.equal(macAddress, that.macAddress);
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hashCode(stag, ctag, macAddress);
+ }
+
+ @Override
+ public String toString() {
+ return MoreObjects.toStringHelper(this)
+ .add("stag", stag)
+ .add("ctag", ctag)
+ .add("macAddress", macAddress)
+ .toString();
+ }
+ }
+
+ /**
+ * Signals that no more IDs are currently available, but some have to be
+ * released before allocating a new one.
+ */
+ class IdExhaustedException extends Exception {
+ }
+}