Support for making requests to Mojang from different IPv4 addresses

(Related #27)

core/src/main/java/com/github/games647/fastlogin/core/BalancedSSLFactory.java

@@ -0,0 +1,80 @@
+package com.github.games647.fastlogin.core;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.Socket;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
+import javax.net.ssl.SSLSocketFactory;
+
+public class BalancedSSLFactory extends SSLSocketFactory {
+
+    private final SSLSocketFactory oldFactory;
+
+    //in order to be thread-safe
+    private final List<InetAddress> localAddresses;
+
+    private final Object lock = new Object();
+
+    private int id;
+
+    public BalancedSSLFactory(SSLSocketFactory oldFactory, Set<InetAddress> localAddresses) {
+        this.oldFactory = oldFactory;
+        this.localAddresses = new ArrayList<>(localAddresses);
+    }
+
+    @Override
+    public String[] getDefaultCipherSuites() {
+        return oldFactory.getDefaultCipherSuites();
+    }
+
+    @Override
+    public String[] getSupportedCipherSuites() {
+        return oldFactory.getSupportedCipherSuites();
+    }
+
+    @Override
+    public Socket createSocket(Socket socket, String host, int port, boolean autoclose) throws IOException {
+        return oldFactory.createSocket(host, port, getNextLocalAddress(), 0);
+    }
+
+    @Override
+    public Socket createSocket(String host, int port) throws IOException, UnknownHostException {
+        return oldFactory.createSocket(host, port, getNextLocalAddress(), 0);
+    }
+
+    @Override
+    public Socket createSocket(String host, int port, InetAddress localAddress, int localPort)
+            throws IOException, UnknownHostException {
+        //default
+        return oldFactory.createSocket(host, port, localAddress, localPort);
+    }
+
+    @Override
+    public Socket createSocket(InetAddress host, int port) throws IOException {
+        return oldFactory.createSocket(host, port, getNextLocalAddress(), 0);
+    }
+
+    @Override
+    public Socket createSocket(InetAddress host, int port, InetAddress local, int localPort) throws IOException {
+        //Default
+        return oldFactory.createSocket(host, port, local, localPort);
+    }
+
+    private InetAddress getNextLocalAddress() {
+        int next;
+        synchronized (lock) {
+            next = id;
+            id++;
+            if (next == Integer.MAX_VALUE) {
+                id = 0;
+            }
+        }
+
+        int index = next % localAddresses.size();
+        return localAddresses.get(index);
+    }
+}

core/src/main/java/com/github/games647/fastlogin/core/MojangApiConnector.java

@@ -4,11 +4,18 @@ import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.net.HttpURLConnection;
+import java.net.InetAddress;
 import java.net.URL;
+import java.net.UnknownHostException;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
 import java.util.UUID;
 import java.util.logging.Level;
 import java.util.regex.Pattern;
 
+import javax.net.ssl.HttpsURLConnection;
+
 public abstract class MojangApiConnector {
 
     //http connection, read timeout and user agent for a connection to mojang api servers
@@ -23,10 +30,33 @@ public abstract class MojangApiConnector {
     //compile the pattern only on plugin enable -> and this have to be threadsafe
     private final Pattern playernameMatcher = Pattern.compile(VALID_PLAYERNAME);
 
+    private final BalancedSSLFactory sslFactory;
+
     protected final FastLoginCore plugin;
 
-    public MojangApiConnector(FastLoginCore plugin) {
+    public MojangApiConnector(FastLoginCore plugin, List<String> localAddresses) {
         this.plugin = plugin;
+
+        if (localAddresses.isEmpty()) {
+            this.sslFactory = null;
+        } else {
+            Set<InetAddress> addresses = new HashSet<>();
+            for (String localAddress : localAddresses) {
+                try {
+                    InetAddress address = InetAddress.getByName(localAddress);
+                    if (!address.isAnyLocalAddress()) {
+                        plugin.getLogger().log(Level.WARNING, "Submitted IP-Address is not local", address);
+                        continue;
+                    }
+
+                    addresses.add(address);
+                } catch (UnknownHostException ex) {
+                    plugin.getLogger().log(Level.SEVERE, "IP-Address is unknown to us", ex);
+                }
+            }
+
+            this.sslFactory = new BalancedSSLFactory(HttpsURLConnection.getDefaultSSLSocketFactory(), addresses);
+        }
     }
 
     /**
@@ -39,7 +69,7 @@ public abstract class MojangApiConnector {
         if (playernameMatcher.matcher(playerName).matches()) {
             //only make a API call if the name is valid existing mojang account
             try {
-                HttpURLConnection connection = getConnection(UUID_LINK + playerName);
+                HttpsURLConnection connection = getConnection(UUID_LINK + playerName);
                 if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                     BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                     String line = reader.readLine();
@@ -61,14 +91,18 @@ public abstract class MojangApiConnector {
 
     protected abstract UUID getUUIDFromJson(String json);
 
-    protected HttpURLConnection getConnection(String url) throws IOException {
-        HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
+    protected HttpsURLConnection getConnection(String url) throws IOException {
+        HttpsURLConnection connection = (HttpsURLConnection) new URL(url).openConnection();
         connection.setConnectTimeout(TIMEOUT);
         connection.setReadTimeout(2 * TIMEOUT);
         //the new Mojang API just uses json as response
         connection.setRequestProperty("Content-Type", "application/json");
         connection.setRequestProperty("User-Agent", USER_AGENT);
 
+        if (sslFactory != null) {
+            connection.setSSLSocketFactory(sslFactory);
+        }
+
         return connection;
     }
 }

core/src/main/resources/config.yml

@@ -106,6 +106,22 @@ forwardSkin: true
 # If they still want to invoke the command, they have to invoke /premium again
 premium-warning: true
 
+# If you have autoRegister or nameChangeCheck enabled, you could be rate-limited by Mojang.
+# The requests of the both options will be only made by FastLogin if the username is unknown to the server
+# You are allowed to make 600 requests per 10-minutes (60 per minute)
+# If you own a big server this value could be too low
+# Once the limit is reached, new players are always logged in as cracked until the rate-limit is expired.
+# (to the next ten minutes)
+#
+# The limit is IP-wide. If you have multiple IPv4-Addreses you specify them here. FastLogin will then use it in rotating
+# order --> 5 different IP-addreses 5 * 600 per 10 minutes
+# If this list is empty only the default one will be used
+#
+# Lists are created like this:
+#ip-addresses:
+#    - 192-168-0-2
+ip-addresses: []
+
 # Database configuration
 # Recommened is the use of MariaDB (a better version of MySQL)