[PAN-2343] smart contract permission controller (#1083)

* [PAN-2343] some stubs in progress

* [PAN-2343] getting close to what could be a working contract controller

* [PAN-2343] added the permissioning provider interface to the smart contract controller

* [PAN-2343] smart permissioning queryer works

* [PAN-2343] docs for the smart contract permissioning controller

* [PAN-2343] removed some bad debugging

* [PAN-2343] docs

* [PAN-2343] final

* [PAN-2343] charsets

* [PAN-2343] dependencies that are missing

ethereum/core/src/main/java/tech/pegasys/pantheon/ethereum/transaction/TransactionSimulator.java

@@ -72,6 +72,10 @@ public Optional<TransactionSimulatorResult> process(
     return process(callParams, header);
   }
 
+  public Optional<TransactionSimulatorResult> processAtHead(final CallParameter callParams) {
+    return process(callParams, blockchain.getChainHeadHeader());
+  }
+
   private Optional<TransactionSimulatorResult> process(
       final CallParameter callParams, final BlockHeader header) {
     if (header == null) {

ethereum/permissioning/build.gradle

@@ -28,12 +28,16 @@ jar {
 dependencies {
   implementation project(':util')
   implementation project(':ethereum:core')
+  implementation project(':crypto')
 
   implementation 'com.google.guava:guava'
   implementation 'net.consensys.cava:cava-toml'
   implementation 'org.apache.logging.log4j:log4j-api'
 
+  testImplementation project(path: ':ethereum:core', configuration: 'testSupportArtifacts')
+  testImplementation project(':config')
   testImplementation 'junit:junit'
+  testImplementation 'io.vertx:vertx-core'
   testImplementation 'org.assertj:assertj-core'
   testImplementation 'org.mockito:mockito-core'
 }

ethereum/permissioning/src/main/java/tech/pegasys/pantheon/ethereum/permissioning/SmartContractPermissioningController.java

@@ -12,24 +12,158 @@
  */
 package tech.pegasys.pantheon.ethereum.permissioning;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import tech.pegasys.pantheon.crypto.Hash;
 import tech.pegasys.pantheon.ethereum.core.Address;
 import tech.pegasys.pantheon.ethereum.permissioning.node.NodePermissioningProvider;
+import tech.pegasys.pantheon.ethereum.transaction.CallParameter;
 import tech.pegasys.pantheon.ethereum.transaction.TransactionSimulator;
+import tech.pegasys.pantheon.ethereum.transaction.TransactionSimulatorResult;
+import tech.pegasys.pantheon.util.bytes.BytesValue;
+import tech.pegasys.pantheon.util.bytes.BytesValues;
 import tech.pegasys.pantheon.util.enode.EnodeURL;
 
-public class SmartContractPermissioningController implements NodePermissioningProvider {
+import java.net.Inet4Address;
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.util.Optional;
 
+/**
+ * Controller that can read from a smart contract that exposes the permissioning calls
+ * connectionAllowedIpv4(bytes32,bytes32,bytes4,uint16,bytes32,bytes32,bytes4,uint16)
+ * connectionAllowedIpv6(bytes32,bytes32,bytes16,uint16,bytes32,bytes32,bytes16,uint16)
+ */
+public class SmartContractPermissioningController implements NodePermissioningProvider {
   private final Address contractAddress;
   private final TransactionSimulator transactionSimulator;
 
+  // full function signature for ipv4 call
+  private static final String IPV4_FUNCTION_SIGNATURE =
+      "connectionAllowedIpv4(bytes32,bytes32,bytes4,uint16,bytes32,bytes32,bytes4,uint16)";
+  // hashed function signature for ipv4 call
+  private static final BytesValue IPV4_FUNCTION_SIGNATURE_HASH =
+      hashSignature(IPV4_FUNCTION_SIGNATURE);
+  // full function signature for ipv6 call
+  private static final String IPV6_FUNCTION_SIGNATURE =
+      "connectionAllowedIpv6(bytes32,bytes32,bytes16,uint16,bytes32,bytes32,bytes16,uint16)";
+  // hashed function signature for ipv6 call
+  private static final BytesValue IPV6_FUNCTION_SIGNATURE_HASH =
+      hashSignature(IPV6_FUNCTION_SIGNATURE);
+
+  // The first 4 bytes of the hash of the full textual signature of the function is used in
+  // contract calls to determine the function being called
+  private static BytesValue hashSignature(final String signature) {
+    return Hash.keccak256(BytesValue.of(signature.getBytes(UTF_8))).slice(0, 4);
+  }
+
+  // True from a contract is 1 filled to 32 bytes
+  private static final BytesValue TRUE_RESPONSE;
+
+  static {
+    final byte[] trueValue = new byte[32];
+    trueValue[31] = (byte) (0xFF & 1L);
+    TRUE_RESPONSE = BytesValue.wrap(trueValue);
+  }
+
+  /**
+   * Creates a permissioning controller attached to a blockchain
+   *
+   * @param contractAddress The address at which the permissioning smart contract resides
+   * @param transactionSimulator A transaction simulator with attached blockchain and world state
+   */
   public SmartContractPermissioningController(
       final Address contractAddress, final TransactionSimulator transactionSimulator) {
     this.contractAddress = contractAddress;
     this.transactionSimulator = transactionSimulator;
   }
 
+  /**
+   * Check whether a given connection from the source to destination enode should be permitted
+   *
+   * @param sourceEnode The enode url of the node initiating the connection
+   * @param destinationEnode The enode url of the node receiving the connection
+   * @return boolean of whether or not to permit the connection to occur
+   */
   @Override
   public boolean isPermitted(final EnodeURL sourceEnode, final EnodeURL destinationEnode) {
-    return true;
+    final BytesValue payload = createPayload(sourceEnode, destinationEnode);
+    final CallParameter callParams =
+        new CallParameter(null, contractAddress, -1, null, null, payload);
+
+    final Optional<TransactionSimulatorResult> result =
+        transactionSimulator.processAtHead(callParams);
+
+    return result.map(r -> checkTransactionResult(r.getOutput())).orElse(false);
+  }
+
+  // Checks the returned bytes from the permissioning contract call to see if it's a value we
+  // understand
+  private Boolean checkTransactionResult(final BytesValue result) {
+    // booleans are padded to 32 bytes
+    if (result.size() != 32) {
+      throw new IllegalArgumentException("Unexpected result size");
+    }
+
+    // 0 is false
+    if (result.isZero()) {
+      return false;
+      // 1 filled to 32 bytes is true
+    } else if (result.compareTo(TRUE_RESPONSE) == 0) {
+      return true;
+      // Anything else is wrong
+    } else {
+      throw new IllegalStateException("Unexpected result form");
+    }
+  }
+
+  // Assemble the bytevalue payload to call the contract
+  private BytesValue createPayload(final EnodeURL sourceEnode, final EnodeURL destinationEnode) {
+    final BytesValue signature;
+    // Grab the right function signature based on the enodes provided
+    if (sourceEnode.getInetAddress() instanceof Inet4Address
+        && destinationEnode.getInetAddress() instanceof Inet4Address) {
+      signature = IPV4_FUNCTION_SIGNATURE_HASH;
+    } else if (sourceEnode.getInetAddress() instanceof Inet6Address
+        && destinationEnode.getInetAddress() instanceof Inet6Address) {
+      signature = IPV6_FUNCTION_SIGNATURE_HASH;
+    } else {
+      // If we got mixed mode enodes then it's wrong
+      throw new IllegalArgumentException(
+          "No payload possible for checking an ipv4 to ipv6 connection");
+    }
+    return BytesValues.concatenate(
+        signature, encodeEnodeUrl(sourceEnode), encodeEnodeUrl(destinationEnode));
+  }
+
+  private BytesValue encodeEnodeUrl(final EnodeURL enode) {
+    return BytesValues.concatenate(
+        encodeEnodeId(enode.getNodeId()),
+        encodeIp(enode.getInetAddress()),
+        encodePort(enode.getListeningPort()));
+  }
+
+  // As a function parameter an ip needs to be the appropriate number of bytes, big endian, and
+  // filled to 32 bytes
+  private BytesValue encodeIp(final InetAddress addr) {
+    // InetAddress deals with giving us the right number of bytes
+    final byte[] address = addr.getAddress();
+    final byte[] res = new byte[32];
+    System.arraycopy(address, 0, res, 0, address.length);
+    return BytesValue.wrap(res);
+  }
+
+  // The port, a uint16, needs to be 2 bytes, little endian, and filled to 32 bytes
+  private BytesValue encodePort(final Integer port) {
+    final byte[] res = new byte[32];
+    res[31] = (byte) ((port) & 0xFF);
+    res[30] = (byte) ((port >> 8) & 0xFF);
+    return BytesValue.wrap(res);
+  }
+
+  // The enode high and low need to be 32 bytes each. They then get concatenated as they are
+  // adjacent parameters
+  private BytesValue encodeEnodeId(final String id) {
+    return BytesValue.fromHexString(id);
   }
 }

ethereum/permissioning/src/test/java/tech/pegasys/pantheon/ethereum/permissioning/SmartContractPermissioningControllerTest.java

@@ -0,0 +1,152 @@
+/*
+ * Copyright 2019 ConsenSys AG.
+ *
+ * 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 tech.pegasys.pantheon.ethereum.permissioning;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.assertj.core.api.Assertions.assertThat;
+import static tech.pegasys.pantheon.ethereum.core.InMemoryStorageProvider.createInMemoryBlockchain;
+import static tech.pegasys.pantheon.ethereum.core.InMemoryStorageProvider.createInMemoryWorldStateArchive;
+
+import tech.pegasys.pantheon.config.GenesisConfigFile;
+import tech.pegasys.pantheon.ethereum.chain.GenesisState;
+import tech.pegasys.pantheon.ethereum.chain.MutableBlockchain;
+import tech.pegasys.pantheon.ethereum.core.Address;
+import tech.pegasys.pantheon.ethereum.mainnet.MainnetProtocolSchedule;
+import tech.pegasys.pantheon.ethereum.mainnet.ProtocolSchedule;
+import tech.pegasys.pantheon.ethereum.transaction.TransactionSimulator;
+import tech.pegasys.pantheon.ethereum.worldstate.WorldStateArchive;
+import tech.pegasys.pantheon.util.enode.EnodeURL;
+
+import java.io.IOException;
+
+import com.google.common.io.Resources;
+import org.junit.Test;
+
+public class SmartContractPermissioningControllerTest {
+
+  private SmartContractPermissioningController setupController(
+      final String resourceName, final String contractAddressString) throws IOException {
+    final ProtocolSchedule<Void> protocolSchedule = MainnetProtocolSchedule.create();
+
+    final String emptyContractFile = Resources.toString(Resources.getResource(resourceName), UTF_8);
+    final GenesisState genesisState =
+        GenesisState.fromConfig(GenesisConfigFile.fromConfig(emptyContractFile), protocolSchedule);
+
+    final MutableBlockchain blockchain = createInMemoryBlockchain(genesisState.getBlock());
+    final WorldStateArchive worldArchive = createInMemoryWorldStateArchive();
+
+    genesisState.writeStateTo(worldArchive.getMutable());
+
+    final TransactionSimulator ts =
+        new TransactionSimulator(blockchain, worldArchive, protocolSchedule);
+    final Address contractAddress = Address.fromHexString(contractAddressString);
+
+    return new SmartContractPermissioningController(contractAddress, ts);
+  }
+
+  @Test
+  public void testIpv4Included() throws IOException {
+    final SmartContractPermissioningController controller =
+        setupController(
+            "SmartContractPermissioningControllerTest/preseededSmartPermissioning.json",
+            "0x0000000000000000000000000000000000001234");
+
+    assertThat(
+            controller.isPermitted(
+                new EnodeURL(
+                    "enode://6f8a80d14311c39f35f516fa664deaaaa13e85b2f7493f37f6144d86991ec012937307647bd3b9a82abe2974e1407241d54947bbb39763a4cac9f77166ad92a0@192.168.0.1:30303"),
+                new EnodeURL(
+                    "enode://6f8a80d14311c39f35f516fa664deaaaa13e85b2f7493f37f6144d86991ec012937307647bd3b9a82abe2974e1407241d54947bbb39763a4cac9f77166ad92a0@192.168.0.1:30304")))
+        .isTrue();
+  }
+
+  @Test
+  public void testIpv4DestinationMissing() throws IOException {
+    final SmartContractPermissioningController controller =
+        setupController(
+            "SmartContractPermissioningControllerTest/preseededSmartPermissioning.json",
+            "0x0000000000000000000000000000000000001234");
+
+    assertThat(
+            controller.isPermitted(
+                new EnodeURL(
+                    "enode://6f8a80d14311c39f35f516fa664deaaaa13e85b2f7493f37f6144d86991ec012937307647bd3b9a82abe2974e1407241d54947bbb39763a4cac9f77166ad92a0@192.168.0.1:30303"),
+                new EnodeURL(
+                    "enode://6f8a80d14311c39f35f516fa664deaaaa13e85b2f7493f37f6144d86991ec012937307647bd3b9a82abe2974e1407241d54947bbb39763a4cac9f77166ad92a0@192.168.0.1:30305")))
+        .isFalse();
+  }
+
+  @Test
+  public void testIpv4SourceMissing() throws IOException {
+    final SmartContractPermissioningController controller =
+        setupController(
+            "SmartContractPermissioningControllerTest/preseededSmartPermissioning.json",
+            "0x0000000000000000000000000000000000001234");
+
+    assertThat(
+            controller.isPermitted(
+                new EnodeURL(
+                    "enode://6f8a80d14311c39f35f516fa664deaaaa13e85b2f7493f37f6144d86991ec012937307647bd3b9a82abe2974e1407241d54947bbb39763a4cac9f77166ad92a0@192.168.0.1:30302"),
+                new EnodeURL(
+                    "enode://6f8a80d14311c39f35f516fa664deaaaa13e85b2f7493f37f6144d86991ec012937307647bd3b9a82abe2974e1407241d54947bbb39763a4cac9f77166ad92a0@192.168.0.1:30304")))
+        .isFalse();
+  }
+
+  @Test
+  public void testIpv6Included() throws IOException {
+    final SmartContractPermissioningController controller =
+        setupController(
+            "SmartContractPermissioningControllerTest/preseededSmartPermissioning.json",
+            "0x0000000000000000000000000000000000001234");
+
+    assertThat(
+            controller.isPermitted(
+                new EnodeURL(
+                    "enode://1234000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000ab61@[1:2:3:4:5:6:7:8]:30303"),
+                new EnodeURL(
+                    "enode://1234000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000ab62@[1:2:3:4:5:6:7:8]:30304")))
+        .isTrue();
+  }
+
+  @Test
+  public void testIpv6SourceMissing() throws IOException {
+    final SmartContractPermissioningController controller =
+        setupController(
+            "SmartContractPermissioningControllerTest/preseededSmartPermissioning.json",
+            "0x0000000000000000000000000000000000001234");
+
+    assertThat(
+            controller.isPermitted(
+                new EnodeURL(
+                    "enode://1234000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000ab63@[1:2:3:4:5:6:7:8]:30303"),
+                new EnodeURL(
+                    "enode://1234000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000ab62@[1:2:3:4:5:6:7:8]:30304")))
+        .isFalse();
+  }
+
+  @Test
+  public void testIpv6DestinationMissing() throws IOException {
+    final SmartContractPermissioningController controller =
+        setupController(
+            "SmartContractPermissioningControllerTest/preseededSmartPermissioning.json",
+            "0x0000000000000000000000000000000000001234");
+
+    assertThat(
+            controller.isPermitted(
+                new EnodeURL(
+                    "enode://1234000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000ab61@[1:2:3:4:5:6:7:8]:30303"),
+                new EnodeURL(
+                    "enode://1234000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000ab63@[1:2:3:4:5:6:7:8]:30304")))
+        .isFalse();
+  }
+}