Add CIDR and IP lookup utilities

src/main/java/org/kiwiproject/net/KiwiCidrs.java

@@ -0,0 +1,126 @@
+package org.kiwiproject.net;
+
+import com.google.common.net.InetAddresses;
+import lombok.extern.slf4j.Slf4j;
+
+import java.math.BigInteger;
+import java.net.InetAddress;
+import java.nio.ByteBuffer;
+
+/**
+ * Small utility to analyze CIDR information.  Supports both IPv4 and IPv6.
+ *
+ * This utility was copied and enhanced from https://github.com/edazdarevic/CIDRUtils which has not been updated since
+ * 2019 and seems to be unmaintained.
+ */
+@SuppressWarnings("UnstableApiUsage")
+@Slf4j
+public class KiwiCidrs {
+
+    private final InetAddress inetAddress;
+    private final int prefixLength;
+
+    private InetAddress startAddress;
+    private InetAddress endAddress;
+    private BigInteger startAddressBigInt;
+    private BigInteger endAddressBigInt;
+
+    /**
+     * Creates a new instance of KiwiCidrs parsing the given CIDR.
+     *
+     * @param cidr the CIDR to use for this instance.
+     */
+    public KiwiCidrs(String cidr) {
+
+        /* split CIDR to address and prefix part */
+        if (cidr.contains("/")) {
+            var index = cidr.indexOf("/");
+            var addressPart = cidr.substring(0, index);
+            var networkPart = cidr.substring(index + 1);
+
+            inetAddress = InetAddresses.forString(addressPart);
+            prefixLength = Integer.parseInt(networkPart);
+
+            calculate();
+        } else {
+            throw new IllegalArgumentException("not a valid CIDR format!");
+        }
+    }
+
+    private void calculate() {
+
+        ByteBuffer maskBuffer;
+        int targetSize;
+        if (inetAddress.getAddress().length == 4) {
+            maskBuffer = ByteBuffer.allocate(4)
+                    .putInt(-1);
+
+            targetSize = 4;
+        } else {
+            maskBuffer = ByteBuffer.allocate(16)
+                    .putLong(-1L)
+                    .putLong(-1L);
+            targetSize = 16;
+        }
+
+        var mask = (new BigInteger(1, maskBuffer.array())).not().shiftRight(prefixLength);
+
+        var buffer = ByteBuffer.wrap(inetAddress.getAddress());
+        var ipVal = new BigInteger(1, buffer.array());
+
+        var startIp = ipVal.and(mask);
+        var endIp = startIp.add(mask.not());
+
+        this.startAddress = targetSize == 4 ? InetAddresses.fromIPv4BigInteger(startIp) : InetAddresses.fromIPv6BigInteger(startIp);
+        this.startAddressBigInt = new BigInteger(1, this.startAddress.getAddress());
+
+        this.endAddress = targetSize == 4 ? InetAddresses.fromIPv4BigInteger(endIp) : InetAddresses.fromIPv6BigInteger(endIp);
+        this.endAddressBigInt = new BigInteger(1, this.endAddress.getAddress());
+
+    }
+
+    /**
+     * Returns the network address for the CIDR.  For example: 192.168.100.15/24 will return 192.168.100.0.
+     *
+     * @return The network address for the CIDR
+     */
+    public String getNetworkAddress() {
+        return this.startAddress.getHostAddress();
+    }
+
+    /**
+     * Returns the broadcast address for the CIDR. For example: 192.168.100.15/24 will return 192.168.100.255.
+     *
+     * @return The broadcast address for the CIDR
+     */
+    public String getBroadcastAddress() {
+        return this.endAddress.getHostAddress();
+    }
+
+    /**
+     * Checks if a given IP address (as a string) is in the CIDR range.
+     *
+     * @param ipAddress the IP address to check
+     * @return true if the IP address is in range, false otherwise
+     */
+    public boolean isInRange(String ipAddress) {
+        var address = InetAddresses.forString(ipAddress);
+        return isInRange(address);
+    }
+
+    /**
+     * Checks if a given IP address (as an {@link InetAddress}) is in the CIDR range.
+     *
+     * @param address the IP address to check
+     * @return true if the IP address is in range, false otherwise
+     */
+    public boolean isInRange(InetAddress address) {
+        var target = new BigInteger(1, address.getAddress());
+
+        if (startAddressBigInt.compareTo(target) > 0){
+            return false; //start is higher than address -> is not in range
+        }
+
+        return endAddressBigInt.compareTo(target) >= 0; // end is higher or equal -> is in range
+    }
+}

src/main/java/org/kiwiproject/net/KiwiInternetAddresses.java

@@ -1,6 +1,7 @@
 package org.kiwiproject.net;
 
 import static com.google.common.base.Strings.nullToEmpty;
+import static java.util.stream.Collectors.toList;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.net.HostAndPort;
@@ -13,10 +14,17 @@
 import lombok.experimental.UtilityClass;
 import lombok.extern.slf4j.Slf4j;
 
+import java.io.UncheckedIOException;
+import java.net.Inet4Address;
+import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.net.MalformedURLException;
+import java.net.NetworkInterface;
+import java.net.SocketException;
 import java.net.URL;
 import java.net.UnknownHostException;
+import java.util.Collections;
+import java.util.List;
 import java.util.Optional;
 import java.util.function.Supplier;
 
@@ -175,6 +183,62 @@ public static HostAndPort hostAndPortFrom(URL url) {
         return HostAndPort.fromParts(url.getHost(), url.getPort());
     }
 
+    /**
+     * Finds the first IP Address on the machine that matches one of the given subnet CIDRs. The {@link IpScheme} is used
+     * to filter the IP addresses by IPv4 or IPv6.
+     *
+     * @param subnetCidrs   A list of CIDRs used to match against the machine's IP addresses.
+     * @param ipScheme      Whether to filter by IPv4 or IPv6
+     * @return the first found matching IP address
+     * @throws IllegalStateException if a matching IP address can not be found.
+     */
+    public static String findFirstMatchingAddress(List<String> subnetCidrs, IpScheme ipScheme) {
+        var ipAddresses = getEnumeratedNetworkAddresses(ipScheme);
+        return findFirstMatchingAddress(subnetCidrs, ipAddresses);
+    }
+
+    @VisibleForTesting
+    static List<String> getEnumeratedNetworkAddresses(IpScheme ipScheme) {
+        try {
+            var interfaces = NetworkInterface.getNetworkInterfaces();
+            return Collections.list(interfaces)
+                    .stream()
+                    .map(networkInterface -> getInterfaceIps(networkInterface, ipScheme))
+                    .flatMap(List::stream)
+                    .collect(toList());
+        } catch (SocketException e) {
+            throw new UncheckedIOException("Error getting enumeration of network interfaces.", e);
+        }
+    }
+
+    private static List<String> getInterfaceIps(NetworkInterface networkInterface, IpScheme ipScheme) {
+        var addresses = networkInterface.getInetAddresses();
+
+        return Collections.list(addresses)
+                .stream()
+                .filter(address -> ipScheme.getInetAddressClass().isAssignableFrom(address.getClass()))
+                .map(InetAddress::getHostAddress)
+                .collect(toList());
+    }
+
+    /**
+     * Finds the first IP Address from a given list of ip addresses that matches one of the given subnet CIDRs.
+     *
+     * @param subnetCidrs   A list of CIDRs used to match against the machine's IP addresses.
+     * @param ipAddresses   A list of IP addresses to search for a match.
+     * @return the first found matching IP address
+     * @throws IllegalStateException if a matching IP address can not be found.
+     */
+    public static String findFirstMatchingAddress(List<String> subnetCidrs, List<String> ipAddresses) {
+        return subnetCidrs.stream()
+                .map(KiwiCidrs::new)
+                .map(cidr -> ipAddresses.stream().filter(cidr::isInRange).findFirst())
+                .flatMap(Optional::stream)
+                .findFirst()
+                .orElseThrow(() ->
+                        new IllegalStateException("Unable to find IP address matching a valid subnet CIDR in: " + subnetCidrs));
+    }
+
     /**
      * Simple value class encapsulating a host name and IP address
      */
@@ -217,4 +281,18 @@ InetAddress getLocalHost() throws UnknownHostException {
             return InetAddress.getLocalHost();
         }
     }
+
+    /**
+     * Enum that defines the IP scheme to use when looking up a machine's IP addresses.
+     */
+    public enum IpScheme {
+        IPV6(Inet6Address.class), IPV4(Inet4Address.class);
+
+        @Getter
+        private final Class<? extends InetAddress> inetAddressClass;
+
+        IpScheme(Class<? extends InetAddress> inetAddressClass) {
+            this.inetAddressClass = inetAddressClass;
+        }
+    }
 }

src/test/java/org/kiwiproject/net/KiwiCidrsTest.java

@@ -0,0 +1,69 @@
+package org.kiwiproject.net;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+@DisplayName("KiwiCidrs")
+class KiwiCidrsTest {
+
+    @Test
+    void shouldThrowIllegalArgumentExceptionIfNotValidCidr() {
+        assertThatThrownBy(() -> new KiwiCidrs("1.2.3.4"))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("not a valid CIDR format!");
+    }
+
+    @ParameterizedTest
+    @CsvSource({
+        "192.168.200.5/32, 192.168.200.5, 192.168.200.5",
+        "192.168.200.5/24, 192.168.200.0, 192.168.200.255",
+        "192.168.200.5/16, 192.168.0.0, 192.168.255.255",
+        "192.168.200.5/8, 192.0.0.0, 192.255.255.255",
+        "192.168.200.5/0, 0.0.0.0, 255.255.255.255",
+        "0.0.0.0/0, 0.0.0.0, 255.255.255.255",
+        "::/0, 0:0:0:0:0:0:0:0, ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
+        "2000::/16, 2000:0:0:0:0:0:0:0, 2000:ffff:ffff:ffff:ffff:ffff:ffff:ffff"
+    })
+    void shouldParseCidr(String cidr, String networkAddress, String broadcastAddress) {
+        var cidrs = new KiwiCidrs(cidr);
+
+        assertThat(cidrs.getNetworkAddress()).isEqualTo(networkAddress);
+        assertThat(cidrs.getBroadcastAddress()).isEqualTo(broadcastAddress);
+    }
+
+    @ParameterizedTest
+    @CsvSource({
+            "192.168.200.5/32, 192.168.200.5",
+            "192.168.200.5/24, 192.168.200.25",
+            "192.168.200.5/16, 192.168.150.50",
+            "192.168.200.5/8, 192.100.150.5",
+            "192.168.200.5/0, 10.10.1.1",
+            "0.0.0.0/0, 10.10.1.1",
+            "::/0, 2001:db8:0000:0000:0000:0000:0000:003f",
+            "2000::/16, 2000:db8:0000:0000:0000:0000:0000:003f"
+    })
+    void shouldReturnTrueWhenAddressIsInRangeOfCidr(String cidr, String address) {
+        var cidrs = new KiwiCidrs(cidr);
+
+        assertThat(cidrs.isInRange(address)).isTrue();
+    }
+
+    @ParameterizedTest
+    @CsvSource({
+            "192.168.200.5/32, 192.168.200.10",
+            "192.168.200.5/24, 192.168.201.25",
+            "192.168.200.5/16, 192.200.150.50",
+            "192.168.200.5/8, 10.100.150.5",
+            "2000::/16, 2001:db8:0000:0000:0000:0000:0000:003f"
+    })
+    void shouldReturnFalseWhenAddressIsNotInRangeOfCidr(String cidr, String address) {
+        var cidrs = new KiwiCidrs(cidr);
+
+        assertThat(cidrs.isInRange(address)).isFalse();
+    }
+}

src/test/java/org/kiwiproject/net/KiwiInternetAddressesTest.java

@@ -1,6 +1,7 @@
 package org.kiwiproject.net;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
@@ -10,14 +11,17 @@
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import org.kiwiproject.net.KiwiInternetAddresses.InetAddressFinder;
+import org.kiwiproject.net.KiwiInternetAddresses.IpScheme;
 import org.kiwiproject.net.KiwiInternetAddresses.SimpleHostInfo;
 
 import java.net.InetAddress;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.UnknownHostException;
+import java.util.List;
 import java.util.function.Supplier;
 
+@SuppressWarnings("UnstableApiUsage")
 @DisplayName("KiwiInternetAddresses")
 class KiwiInternetAddressesTest {
 
@@ -233,4 +237,58 @@ private InetAddress dummyInetAddress() {
             throw new RuntimeException(e);
         }
     }
+
+    @Test
+    void shouldGetEnumeratedNetworkAddresses() {
+        var ipv4Addresses = KiwiInternetAddresses.getEnumeratedNetworkAddresses(IpScheme.IPV4);
+        assertThat(ipv4Addresses).isNotEmpty();
+
+        var ipv6Addresses = KiwiInternetAddresses.getEnumeratedNetworkAddresses(IpScheme.IPV6);
+        assertThat(ipv6Addresses).isNotEmpty();
+    }
+
+    @Test
+    void shouldThrowIllegalStateWhenIpAddressesNotInSubnetCidrs() {
+        var subnetCidrs = List.of("192.168.50.0/24", "192.168.100.0/24", "192.168.150.0/24");
+        var ipAddresses = List.of("192.168.200.5");
+
+        assertThatIllegalStateException()
+                .isThrownBy(() -> KiwiInternetAddresses.findFirstMatchingAddress(subnetCidrs, ipAddresses))
+                .withMessageStartingWith("Unable to find IP address matching a valid subnet CIDR in: ");
+    }
+
+    @Test
+    void shouldReturnFoundAddressThatMatchesAGivenCidrFromGivenListOfAddresses() {
+        var subnetCidrs = List.of("192.168.50.0/24", "192.168.100.0/24", "192.168.150.0/24");
+        var ipAddresses = List.of("192.168.100.5", "192.168.200.5", "192.168.10.5");
+
+        var address = KiwiInternetAddresses.findFirstMatchingAddress(subnetCidrs, ipAddresses);
+
+        assertThat(address).isEqualTo("192.168.100.5");
+    }
+
+    @Test
+    void shouldReturnFoundAddressThatMatchesAGivenIpv4CidrByLookingUpAddresses() {
+        var subnetCidrs = List.of("0.0.0.0/0");
+
+        var address = KiwiInternetAddresses.findFirstMatchingAddress(subnetCidrs, IpScheme.IPV4);
+
+        assertThat(address).isNotBlank();
+    }
+
+    @Test
+    void shouldReturnFoundAddressThatMatchesAGivenIpv6CidrByLookingUpAddresses() {
+        var subnetCidrs = List.of("::/0");
+
+        var address = KiwiInternetAddresses.findFirstMatchingAddress(subnetCidrs, IpScheme.IPV6);
+
+        assertThat(address).isNotBlank();
+    }
+
+    @Test
+    void shouldThrowIllegalStateWhenRequestedIPDoesNotMatchCidrScheme() {
+        assertThatIllegalStateException()
+                .isThrownBy(() -> KiwiInternetAddresses.findFirstMatchingAddress(List.of("127.0.0.1/8"), IpScheme.IPV6))
+                .withMessageStartingWith("Unable to find IP address matching a valid subnet CIDR in: ");
+    }
 }