Add experimental config option to enable v5 discovery

besu/src/main/java/org/hyperledger/besu/RunnerBuilder.java

@@ -419,6 +419,8 @@ public Runner build() {
       }
       discoveryConfiguration.setBootnodes(bootstrap);
       discoveryConfiguration.setDnsDiscoveryURL(ethNetworkConfig.getDnsDiscoveryUrl());
+      discoveryConfiguration.setDiscoveryV5Enabled(
+          networkingConfiguration.getDiscovery().isDiscoveryV5Enabled());
     } else {
       discoveryConfiguration.setActive(false);
     }

besu/src/main/java/org/hyperledger/besu/cli/options/unstable/NetworkingOptions.java

@@ -30,6 +30,7 @@ public class NetworkingOptions implements CLIOptions<NetworkingConfiguration> {
   private final String CHECK_MAINTAINED_CONNECTIONS_FREQUENCY_FLAG =
       "--Xp2p-check-maintained-connections-frequency";
   private final String DNS_DISCOVERY_SERVER_OVERRIDE_FLAG = "--Xp2p-dns-discovery-server";
+  private final String DISCOVERY_PROTOCOL_V5_ENABLED = "--Xv5-discovery-enabled";
 
   @CommandLine.Option(
       names = INITIATE_CONNECTIONS_FREQUENCY_FLAG,
@@ -58,6 +59,13 @@ public class NetworkingOptions implements CLIOptions<NetworkingConfiguration> {
           "DNS server host to use for doing DNS Discovery of peers, rather than the machine's configured DNS server")
   private Optional<String> dnsDiscoveryServerOverride = Optional.empty();
 
+  @CommandLine.Option(
+      names = DISCOVERY_PROTOCOL_V5_ENABLED,
+      hidden = true,
+      defaultValue = "false",
+      description = "Whether to enable P2P Discovery Protocol v5 (default: ${DEFAULT-VALUE})")
+  private final Boolean isPeerDiscoveryV5Enabled = false;
+
   private NetworkingOptions() {}
 
   public static NetworkingOptions create() {
@@ -81,7 +89,7 @@ public NetworkingConfiguration toDomainObject() {
     config.setCheckMaintainedConnectionsFrequency(checkMaintainedConnectionsFrequencySec);
     config.setInitiateConnectionsFrequency(initiateConnectionsFrequencySec);
     config.setDnsDiscoveryServerOverride(dnsDiscoveryServerOverride);
-
+    config.getDiscovery().setDiscoveryV5Enabled(isPeerDiscoveryV5Enabled);
     return config;
   }
 

besu/src/test/java/org/hyperledger/besu/cli/options/NetworkingOptionsTest.java

@@ -101,6 +101,30 @@ public void checkDnsServerOverrideFlag_isNotSet() {
     assertThat(commandOutput.toString(UTF_8)).isEmpty();
   }
 
+  @Test
+  public void checkDiscoveryV5Enabled_isSet() {
+    final TestBesuCommand cmd = parseCommand("--Xv5-discovery-enabled");
+
+    final NetworkingOptions options = cmd.getNetworkingOptions();
+    final NetworkingConfiguration networkingConfig = options.toDomainObject();
+    assertThat(networkingConfig.getDiscovery().isDiscoveryV5Enabled()).isTrue();
+
+    assertThat(commandErrorOutput.toString(UTF_8)).isEmpty();
+    assertThat(commandOutput.toString(UTF_8)).isEmpty();
+  }
+
+  @Test
+  public void checkDiscoveryV5Enabled_isNotSet() {
+    final TestBesuCommand cmd = parseCommand();
+
+    final NetworkingOptions options = cmd.getNetworkingOptions();
+    final NetworkingConfiguration networkingConfig = options.toDomainObject();
+    assertThat(networkingConfig.getDiscovery().isDiscoveryV5Enabled()).isFalse();
+
+    assertThat(commandErrorOutput.toString(UTF_8)).isEmpty();
+    assertThat(commandOutput.toString(UTF_8)).isEmpty();
+  }
+
   @Override
   NetworkingConfiguration createDefaultDomainObject() {
     return NetworkingConfiguration.create();

ethereum/p2p/src/main/java/org/hyperledger/besu/ethereum/p2p/config/DiscoveryConfiguration.java

@@ -31,6 +31,7 @@ public class DiscoveryConfiguration {
   private int bucketSize = 16;
   private List<EnodeURL> bootnodes = new ArrayList<>();
   private String dnsDiscoveryURL;
+  private boolean discoveryV5Enabled = false;
 
   public static DiscoveryConfiguration create() {
     return new DiscoveryConfiguration();
@@ -113,6 +114,14 @@ public DiscoveryConfiguration setDnsDiscoveryURL(final String dnsDiscoveryURL) {
     return this;
   }
 
+  public boolean isDiscoveryV5Enabled() {
+    return discoveryV5Enabled;
+  }
+
+  public void setDiscoveryV5Enabled(final boolean discoveryV5Enabled) {
+    this.discoveryV5Enabled = discoveryV5Enabled;
+  }
+
   @Override
   public boolean equals(final Object o) {
     if (o == this) {

ethereum/p2p/src/main/java/org/hyperledger/besu/ethereum/p2p/network/DefaultP2PNetwork.java

@@ -204,6 +204,10 @@ public void start() {
       return;
     }
 
+    if (config.getDiscovery().isDiscoveryV5Enabled()) {
+      LOG.warn("Discovery Protocol v5 is not available");
+    }
+
     final String address = config.getDiscovery().getAdvertisedHost();
     final int configuredDiscoveryPort = config.getDiscovery().getBindPort();
     final int configuredRlpxPort = config.getRlpx().getBindPort();