config: Refactor IPCidr and use of InetAddress

Use a canonically-named utility class to tack on methods to the existing
InetAddress class. Rename IPCidr to InetNetwork so it better matches
InetAddress and is more pronouceable :) While here, simplify the
constructor and toString() functions, and properly implement hashCode().

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

app/src/main/java/com/wireguard/android/backend/GoBackend.java

@@ -21,7 +21,7 @@ import com.wireguard.android.model.Tunnel.Statistics;
 import com.wireguard.android.util.ExceptionLoggers;
 import com.wireguard.android.util.SharedLibraryLoader;
 import com.wireguard.config.Config;
-import com.wireguard.config.IPCidr;
+import com.wireguard.config.InetNetwork;
 import com.wireguard.config.Interface;
 import com.wireguard.config.Peer;
 import com.wireguard.crypto.KeyEncoding;
@@ -156,7 +156,7 @@ public final class GoBackend implements Backend {
                         fmt.format("endpoint=%s\n", peer.getResolvedEndpointString());
                     if (peer.getPersistentKeepalive() != 0)
                         fmt.format("persistent_keepalive_interval=%d\n", peer.getPersistentKeepalive());
-                    for (final IPCidr addr : peer.getAllowedIPs()) {
+                    for (final InetNetwork addr : peer.getAllowedIPs()) {
                         fmt.format("allowed_ip=%s\n", addr.toString());
                     }
                 }
@@ -171,15 +171,15 @@ public final class GoBackend implements Backend {
             configureIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
             builder.setConfigureIntent(PendingIntent.getActivity(context, 0, configureIntent, 0));
 
-            for (final IPCidr addr : config.getInterface().getAddresses())
+            for (final InetNetwork addr : config.getInterface().getAddresses())
-                builder.addAddress(addr.getAddress(), addr.getCidr());
+                builder.addAddress(addr.getAddress(), addr.getMask());
 
             for (final InetAddress addr : config.getInterface().getDnses())
                 builder.addDnsServer(addr.getHostAddress());
 
             for (final Peer peer : config.getPeers()) {
-                for (final IPCidr addr : peer.getAllowedIPs())
+                for (final InetNetwork addr : peer.getAllowedIPs())
-                    builder.addRoute(addr.getAddress(), addr.getCidr());
+                    builder.addRoute(addr.getAddress(), addr.getMask());
             }
 
             int mtu = config.getInterface().getMtu();

app/src/main/java/com/wireguard/config/Attribute.java

@@ -8,9 +8,6 @@ package com.wireguard.config;
 
 import android.text.TextUtils;
 
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
-import java.net.InetAddress;
 import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
@@ -36,7 +33,6 @@ enum Attribute {
     private static final String[] EMPTY_LIST = new String[0];
     private static final Map<String, Attribute> KEY_MAP;
     private static final Pattern LIST_SEPARATOR_PATTERN = Pattern.compile("\\s*,\\s*");
-    private static final Method NUMERIC_ADDRESS_PARSER;
     private static final Pattern SEPARATOR_PATTERN = Pattern.compile("\\s|=");
 
     static {
@@ -46,14 +42,6 @@ enum Attribute {
         }
     }
 
-    static {
-        try {
-            NUMERIC_ADDRESS_PARSER = InetAddress.class.getMethod("parseNumericAddress", String.class);
-        } catch (final Exception e) {
-            throw new RuntimeException(e);
-        }
-    }
-
     private final Pattern pattern;
     private final String token;
 
@@ -70,21 +58,6 @@ enum Attribute {
         return KEY_MAP.get(SEPARATOR_PATTERN.split(line)[0].toLowerCase());
     }
 
-    public static InetAddress parseIPString(final String address) {
-        if (address == null || address.isEmpty())
-            throw new IllegalArgumentException("Empty address");
-        try {
-            return (InetAddress) NUMERIC_ADDRESS_PARSER.invoke(null, address);
-        } catch (final IllegalAccessException e) {
-            throw new RuntimeException(e);
-        } catch (final InvocationTargetException e) {
-            if (e.getCause() instanceof IllegalArgumentException)
-                throw (IllegalArgumentException) e.getCause();
-            else
-                throw new IllegalArgumentException(e.getCause());
-        }
-    }
-
     public static String[] stringToList(final String string) {
         if (string == null)
             return EMPTY_LIST;

app/src/main/java/com/wireguard/config/IPCidr.java

@@ -1,48 +0,0 @@
-/*
- * Copyright © 2018 Samuel Holland <samuel@sholland.org>
- * Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
- * SPDX-License-Identifier: GPL-2.0-or-later
- */
-
-package com.wireguard.config;
-
-import java.net.Inet4Address;
-import java.net.Inet6Address;
-import java.net.InetAddress;
-import java.util.Locale;
-
-public class IPCidr {
-    private final InetAddress address;
-    private int cidr;
-
-    @SuppressWarnings("MagicNumber")
-    public IPCidr(String in) {
-        cidr = -1;
-        final int slash = in.lastIndexOf('/');
-        if (slash != -1 && slash < in.length() - 1) {
-            try {
-                cidr = Integer.parseInt(in.substring(slash + 1), 10);
-                in = in.substring(0, slash);
-            } catch (final Exception ignored) {
-            }
-        }
-        address = Attribute.parseIPString(in);
-        if ((address instanceof Inet6Address) && (cidr > 128 || cidr < 0))
-            cidr = 128;
-        else if ((address instanceof Inet4Address) && (cidr > 32 || cidr < 0))
-            cidr = 32;
-    }
-
-    public InetAddress getAddress() {
-        return address;
-    }
-
-    public int getCidr() {
-        return cidr;
-    }
-
-    @Override
-    public String toString() {
-        return String.format(Locale.getDefault(), "%s/%d", address.getHostAddress(), cidr);
-    }
-}

app/src/main/java/com/wireguard/config/InetAddresses.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright © 2018 Samuel Holland <samuel@sholland.org>
+ * Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+package com.wireguard.config;
+
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.net.InetAddress;
+
+public final class InetAddresses {
+    private static final Method PARSER_METHOD;
+
+    static {
+        try {
+            // This method is only present on Android.
+            PARSER_METHOD = InetAddress.class.getMethod("parseNumericAddress", String.class);
+        } catch (final NoSuchMethodException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private InetAddresses() {
+        // Prevent instantiation.
+    }
+
+    @NonNull
+    public static InetAddress parse(@Nullable final String address) {
+        if (address == null || address.isEmpty())
+            throw new IllegalArgumentException("Empty address");
+        try {
+            return (InetAddress) PARSER_METHOD.invoke(null, address);
+        } catch (final IllegalAccessException | InvocationTargetException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}

app/src/main/java/com/wireguard/config/InetNetwork.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright © 2018 Samuel Holland <samuel@sholland.org>
+ * Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+package com.wireguard.config;
+
+import android.support.annotation.NonNull;
+
+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.util.Objects;
+
+public class InetNetwork {
+    private final InetAddress address;
+    private final int mask;
+
+    public InetNetwork(@NonNull final String input) {
+        final int slash = input.lastIndexOf('/');
+        final int rawMask;
+        final String rawAddress;
+        if (slash >= 0) {
+            rawMask = Integer.parseInt(input.substring(slash + 1), 10);
+            rawAddress = input.substring(0, slash);
+        } else {
+            rawMask = -1;
+            rawAddress = input;
+        }
+        address = InetAddresses.parse(rawAddress);
+        final int maxMask = (address instanceof Inet4Address) ? 32 : 128;
+        mask = rawMask >= 0 && rawMask <= maxMask ? rawMask : maxMask;
+    }
+
+    @Override
+    public boolean equals(final Object obj) {
+        if (!(obj instanceof InetNetwork))
+            return false;
+        final InetNetwork other = (InetNetwork) obj;
+        return Objects.equals(address, other.address) && mask == other.mask;
+    }
+
+    @NonNull
+    public InetAddress getAddress() {
+        return address;
+    }
+
+    public int getMask() {
+        return mask;
+    }
+
+    @Override
+    public int hashCode() {
+        return address.hashCode() ^ mask;
+    }
+
+    @Override
+    public String toString() {
+        return address.getHostAddress() + '/' + mask;
+    }
+}

app/src/main/java/com/wireguard/config/Interface.java

@@ -23,7 +23,7 @@ import java.util.List;
  */
 
 public class Interface {
-    private final List<IPCidr> addressList;
+    private final List<InetNetwork> addressList;
     private final List<InetAddress> dnsList;
     private Keypair keypair;
     private int listenPort;
@@ -39,7 +39,7 @@ public class Interface {
             for (final String addr : addresses) {
                 if (addr.isEmpty())
                     throw new IllegalArgumentException("Address is empty");
-                addressList.add(new IPCidr(addr));
+                addressList.add(new InetNetwork(addr));
             }
         }
     }
@@ -47,7 +47,7 @@ public class Interface {
     private void addDnses(final String[] dnses) {
         if (dnses != null && dnses.length > 0) {
             for (final String dns : dnses) {
-                dnsList.add(Attribute.parseIPString(dns));
+                dnsList.add(InetAddresses.parse(dns));
             }
         }
     }
@@ -58,8 +58,8 @@ public class Interface {
         return Attribute.iterableToString(addressList);
     }
 
-    public IPCidr[] getAddresses() {
+    public InetNetwork[] getAddresses() {
-        return addressList.toArray(new IPCidr[addressList.size()]);
+        return addressList.toArray(new InetNetwork[addressList.size()]);
     }
 
     private String getDnsString() {

app/src/main/java/com/wireguard/config/Peer.java

@@ -28,7 +28,7 @@ import java.util.Locale;
  */
 
 public class Peer {
-    private final List<IPCidr> allowedIPsList;
+    private final List<InetNetwork> allowedIPsList;
     private InetSocketAddress endpoint;
     private int persistentKeepalive;
     private String preSharedKey;
@@ -41,13 +41,13 @@ public class Peer {
     private void addAllowedIPs(final String[] allowedIPs) {
         if (allowedIPs != null && allowedIPs.length > 0) {
             for (final String allowedIP : allowedIPs) {
-                allowedIPsList.add(new IPCidr(allowedIP));
+                allowedIPsList.add(new InetNetwork(allowedIP));
             }
         }
     }
 
-    public IPCidr[] getAllowedIPs() {
+    public InetNetwork[] getAllowedIPs() {
-        return allowedIPsList.toArray(new IPCidr[allowedIPsList.size()]);
+        return allowedIPsList.toArray(new InetNetwork[allowedIPsList.size()]);
     }
 
     private String getAllowedIPsString() {