Java tutorial
/* * Copyright 2016-present Open Networking Laboratory * * 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.bmv2.demo.app.wcmp; import com.eclipsesource.json.Json; import com.eclipsesource.json.JsonObject; import com.google.common.collect.ImmutableList; import com.google.common.collect.Lists; import com.google.common.collect.Maps; import com.google.common.collect.Sets; import org.apache.commons.lang3.tuple.Pair; import org.apache.felix.scr.annotations.Component; import org.apache.felix.scr.annotations.Reference; import org.apache.felix.scr.annotations.ReferenceCardinality; import org.onosproject.bmv2.api.context.Bmv2Configuration; import org.onosproject.bmv2.api.context.Bmv2DefaultConfiguration; import org.onosproject.bmv2.api.context.Bmv2DeviceContext; import org.onosproject.bmv2.api.runtime.Bmv2Action; import org.onosproject.bmv2.api.runtime.Bmv2DeviceAgent; import org.onosproject.bmv2.api.runtime.Bmv2ExtensionSelector; import org.onosproject.bmv2.api.runtime.Bmv2ExtensionTreatment; import org.onosproject.bmv2.api.runtime.Bmv2RuntimeException; import org.onosproject.bmv2.api.service.Bmv2Controller; import org.onosproject.bmv2.demo.app.common.AbstractUpgradableFabricApp; import org.onosproject.net.DeviceId; import org.onosproject.net.Host; import org.onosproject.net.Path; import org.onosproject.net.PortNumber; import org.onosproject.net.flow.DefaultTrafficSelector; import org.onosproject.net.flow.DefaultTrafficTreatment; import org.onosproject.net.flow.FlowRule; import org.onosproject.net.flow.TrafficTreatment; import org.onosproject.net.flow.criteria.ExtensionSelector; import org.onosproject.net.flow.instructions.ExtensionTreatment; import org.onosproject.net.topology.DefaultTopologyVertex; import org.onosproject.net.topology.Topology; import org.onosproject.net.topology.TopologyGraph; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.List; import java.util.Map; import java.util.Set; import java.util.stream.Collectors; import static java.util.stream.Collectors.toList; import static java.util.stream.Collectors.toSet; import static org.onlab.packet.EthType.EtherType.IPV4; import static org.onosproject.bmv2.api.utils.Bmv2TranslatorUtils.roundToBytes; import static org.onosproject.bmv2.demo.app.wcmp.WcmpInterpreter.*; /** * Implementation of an upgradable fabric app for the WCMP configuration. */ @Component(immediate = true) public class WcmpFabricApp extends AbstractUpgradableFabricApp { private static final String APP_NAME = "org.onosproject.bmv2-wcmp-fabric"; private static final String MODEL_NAME = "WCMP"; private static final String JSON_CONFIG_PATH = "/wcmp.json"; private static final double MULTI_PORT_WEIGHT_COEFFICIENT = 0.85; private static final Bmv2Configuration WCMP_CONFIGURATION = loadConfiguration(); private static final WcmpInterpreter WCMP_INTERPRETER = new WcmpInterpreter(); protected static final Bmv2DeviceContext WCMP_CONTEXT = new Bmv2DeviceContext(WCMP_CONFIGURATION, WCMP_INTERPRETER); private static final Map<DeviceId, Map<Map<PortNumber, Double>, Integer>> DEVICE_GROUP_ID_MAP = Maps .newHashMap(); @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) private Bmv2Controller bmv2Controller; /** * TODO. */ public WcmpFabricApp() { super(APP_NAME, MODEL_NAME, WCMP_CONTEXT); } @Override public boolean initDevice(DeviceId deviceId) { try { Bmv2DeviceAgent agent = bmv2Controller.getAgent(deviceId); for (Map.Entry<String, Bmv2Action> entry : WCMP_INTERPRETER.defaultActionsMap().entrySet()) { agent.setTableDefaultAction(entry.getKey(), entry.getValue()); } return true; } catch (Bmv2RuntimeException e) { log.debug("Exception while initializing device {}: {}", deviceId, e.explain()); return false; } } @Override public List<FlowRule> generateLeafRules(DeviceId deviceId, Host srcHost, Collection<Host> dstHosts, Collection<DeviceId> availableSpines, Topology topo) throws FlowRuleGeneratorException { Set<PortNumber> hostPortNumbers = Sets.newHashSet(); Set<PortNumber> fabricPortNumbers = Sets.newHashSet(); deviceService.getPorts(deviceId) .forEach(p -> (isFabricPort(p, topo) ? fabricPortNumbers : hostPortNumbers).add(p.number())); if (hostPortNumbers.size() != 1 || fabricPortNumbers.size() == 0) { log.error("Leaf switch has invalid port configuration: hostPorts={}, fabricPorts={}", hostPortNumbers.size(), fabricPortNumbers.size()); throw new FlowRuleGeneratorException(); } PortNumber hostPort = hostPortNumbers.iterator().next(); TopologyGraph graph = topologyService.getGraph(topo); // Map key: spine device id, value: leaf switch ports which connect to spine in the key. Map<DeviceId, Set<PortNumber>> spineToPortsMap = Maps.newHashMap(); graph.getEdgesFrom(new DefaultTopologyVertex(deviceId)).forEach(edge -> { spineToPortsMap.putIfAbsent(edge.dst().deviceId(), Sets.newHashSet()); spineToPortsMap.get(edge.dst().deviceId()).add(edge.link().src().port()); }); double baseWeight = 1d / spineToPortsMap.size(); int numSinglePorts = (int) spineToPortsMap.values().stream().filter(s -> s.size() == 1).count(); int numMultiPorts = spineToPortsMap.size() - numSinglePorts; // Reduce weight portion assigned to multi-ports to mitigate flow assignment imbalance (measured empirically). double multiPortBaseWeight = baseWeight * MULTI_PORT_WEIGHT_COEFFICIENT; double excess = (baseWeight - multiPortBaseWeight) * numMultiPorts; double singlePortBaseWeight = baseWeight + (excess / numSinglePorts); Map<PortNumber, Double> weighedPortNumbers = Maps.newHashMap(); spineToPortsMap.forEach((did, portSet) -> { double base = (portSet.size() == 1) ? singlePortBaseWeight : multiPortBaseWeight; double weight = base / portSet.size(); portSet.forEach(portNumber -> weighedPortNumbers.put(portNumber, weight)); }); List<FlowRule> rules = Lists.newArrayList(); Pair<ExtensionTreatment, List<FlowRule>> result = provisionWcmpTreatment(deviceId, weighedPortNumbers); ExtensionTreatment wcmpTreatment = result.getLeft(); rules.addAll(result.getRight()); // From src host to dst hosts, WCMP to all fabric ports. for (Host dstHost : dstHosts) { FlowRule rule = flowRuleBuilder(deviceId, TABLE0) .withSelector(DefaultTrafficSelector.builder().matchInPort(hostPort) .matchEthType(IPV4.ethType().toShort()).matchEthSrc(srcHost.mac()) .matchEthDst(dstHost.mac()).build()) .withTreatment(DefaultTrafficTreatment.builder().extension(wcmpTreatment, deviceId).build()) .build(); rules.add(rule); } // From fabric ports to src host. for (PortNumber port : fabricPortNumbers) { FlowRule rule = flowRuleBuilder(deviceId, TABLE0) .withSelector(DefaultTrafficSelector.builder().matchInPort(port) .matchEthType(IPV4.ethType().toShort()).matchEthDst(srcHost.mac()).build()) .withTreatment(DefaultTrafficTreatment.builder().setOutput(hostPort).build()).build(); rules.add(rule); } return rules; } @Override public List<FlowRule> generateSpineRules(DeviceId deviceId, Collection<Host> dstHosts, Topology topo) throws FlowRuleGeneratorException { List<FlowRule> rules = Lists.newArrayList(); for (Host dstHost : dstHosts) { Set<Path> paths = topologyService.getPaths(topo, deviceId, dstHost.location().deviceId()); if (paths.size() == 0) { log.warn("Can't find any path between spine {} and host {}", deviceId, dstHost); throw new FlowRuleGeneratorException(); } TrafficTreatment treatment; if (paths.size() == 1) { // Only one path. PortNumber port = paths.iterator().next().src().port(); treatment = DefaultTrafficTreatment.builder().setOutput(port).build(); } else { // Multiple paths, do WCMP. Set<PortNumber> portNumbers = paths.stream().map(p -> p.src().port()).collect(toSet()); double weight = 1d / portNumbers.size(); // Same weight for all ports. Map<PortNumber, Double> weightedPortNumbers = portNumbers.stream() .collect(Collectors.toMap(p -> p, p -> weight)); Pair<ExtensionTreatment, List<FlowRule>> result = provisionWcmpTreatment(deviceId, weightedPortNumbers); rules.addAll(result.getRight()); treatment = DefaultTrafficTreatment.builder().extension(result.getLeft(), deviceId).build(); } FlowRule rule = flowRuleBuilder(deviceId, TABLE0).withSelector(DefaultTrafficSelector.builder() .matchEthType(IPV4.ethType().toShort()).matchEthDst(dstHost.mac()).build()) .withTreatment(treatment).build(); rules.add(rule); } return rules; } private Pair<ExtensionTreatment, List<FlowRule>> provisionWcmpTreatment(DeviceId deviceId, Map<PortNumber, Double> weightedFabricPorts) throws FlowRuleGeneratorException { // Install WCMP group table entries that map from hash values to fabric ports. int groupId = groupIdOf(deviceId, weightedFabricPorts); List<PortNumber> portNumbers = Lists.newArrayList(); List<Double> weights = Lists.newArrayList(); weightedFabricPorts.forEach((p, w) -> { portNumbers.add(p); weights.add(w); }); List<Integer> prefixLengths = toPrefixLengths(weights); List<FlowRule> rules = Lists.newArrayList(); for (int i = 0; i < portNumbers.size(); i++) { ExtensionSelector extSelector = buildWcmpSelector(groupId, prefixLengths.get(i)); FlowRule rule = flowRuleBuilder(deviceId, WCMP_GROUP_TABLE) .withSelector(DefaultTrafficSelector.builder().extension(extSelector, deviceId).build()) .withTreatment(DefaultTrafficTreatment.builder().setOutput(portNumbers.get(i)).build()).build(); rules.add(rule); } ExtensionTreatment extTreatment = buildWcmpTreatment(groupId); return Pair.of(extTreatment, rules); } private Bmv2ExtensionSelector buildWcmpSelector(int groupId, int prefixLength) { byte[] ones = new byte[roundToBytes(prefixLength)]; Arrays.fill(ones, (byte) 0xFF); return Bmv2ExtensionSelector.builder().forConfiguration(WCMP_CONTEXT.configuration()) .matchExact(WCMP_META, GROUP_ID, groupId).matchLpm(WCMP_META, SELECTOR, ones, prefixLength).build(); } private Bmv2ExtensionTreatment buildWcmpTreatment(int groupId) { return Bmv2ExtensionTreatment.builder().forConfiguration(WCMP_CONTEXT.configuration()) .setActionName(WCMP_GROUP).addParameter(GROUP_ID, groupId).build(); } public int groupIdOf(DeviceId did, Map<PortNumber, Double> weightedPorts) { DEVICE_GROUP_ID_MAP.putIfAbsent(did, Maps.newHashMap()); // Counts the number of unique portNumber sets for each device ID. // Each distinct set of portNumbers will have a unique ID. return DEVICE_GROUP_ID_MAP.get(did).computeIfAbsent(weightedPorts, (pp) -> DEVICE_GROUP_ID_MAP.get(did).size() + 1); } public List<Integer> toPrefixLengths(List<Double> weigths) { final double weightSum = weigths.stream().mapToDouble(Double::doubleValue).map(this::roundDouble).sum(); if (Math.abs(weightSum - 1) > 0.0001) { throw new RuntimeException("WCMP weights sum is expected to be 1, found was " + weightSum); } final int selectorBitWidth = WCMP_CONTEXT.configuration().headerType(WCMP_META_T).field(SELECTOR) .bitWidth(); final int availableBits = selectorBitWidth - 1; List<Long> prefixDiffs = weigths.stream().map(w -> Math.round(w * availableBits)).collect(toList()); final long bitSum = prefixDiffs.stream().mapToLong(Long::longValue).sum(); final long error = availableBits - bitSum; if (error != 0) { // Lazy intuition here is that the error can be absorbed by the longest prefixDiff with the minor impact. Long maxDiff = Collections.max(prefixDiffs); int idx = prefixDiffs.indexOf(maxDiff); prefixDiffs.remove(idx); prefixDiffs.add(idx, maxDiff + error); } List<Integer> prefixLengths = Lists.newArrayList(); int prefix = 1; for (Long p : prefixDiffs) { prefixLengths.add(prefix); prefix += p; } return ImmutableList.copyOf(prefixLengths); } private double roundDouble(double n) { // 5 digits precision. return (double) Math.round(n * 100000d) / 100000d; } private static Bmv2Configuration loadConfiguration() { try { JsonObject json = Json .parse(new BufferedReader( new InputStreamReader(WcmpFabricApp.class.getResourceAsStream(JSON_CONFIG_PATH)))) .asObject(); return Bmv2DefaultConfiguration.parse(json); } catch (IOException e) { throw new RuntimeException("Unable to load configuration", e); } } }