Implement Support for MinecraftForge / FML 1.7.10

Additional implementation help provided by @jk-5 and @bloodmc.

api/src/main/java/net/md_5/bungee/api/ServerPing.java

@@ -1,5 +1,7 @@
 package net.md_5.bungee.api;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.UUID;
 import lombok.AllArgsConstructor;
 import lombok.Data;
@@ -74,6 +76,27 @@ public class ServerPing
     private String description;
     private Favicon favicon;
 
+    @Data
+    public static class ModInfo
+    {
+
+        private String type = "FML";
+        private List<ModItem> modList = new ArrayList<>();
+    }
+
+    @Data
+    @AllArgsConstructor
+    public static class ModItem
+    {
+
+        private String modid;
+        private String version;
+    }
+
+    // Right now, we don't get the mods from the user, so we just use a stock ModInfo object to
+    // create the server ping. Vanilla clients will ignore this.
+    private final ModInfo modinfo = new ModInfo();
+
     @Deprecated
     public ServerPing(Protocol version, Players players, String description, String favicon)
     {

api/src/main/java/net/md_5/bungee/api/connection/ProxiedPlayer.java

@@ -1,6 +1,7 @@
 package net.md_5.bungee.api.connection;
 
 import java.util.Locale;
+import java.util.Map;
 import java.util.UUID;
 import net.md_5.bungee.api.Callback;
 import net.md_5.bungee.api.CommandSender;
@@ -153,4 +154,28 @@ public interface ProxiedPlayer extends Connection, CommandSender
      * @see Title
      */
     void sendTitle(Title title);
+
+    /**
+     * Gets this player's Forge Mod List, if the player has sent this
+     * information during the lifetime of their connection to Bungee. There is
+     * no guarantee that information is available at any time, as it is only
+     * sent during a FML handshake. Therefore, this will only contain
+     * information for a user that has attempted joined a Forge server.
+     * <p>
+     * Consumers of this API should be aware that an empty mod list does
+     * <em>not</em> indicate that a user is not a Forge user, and so should not
+     * use this API to check for this - there is no way to tell this reliably.
+     * </p>
+     * <p>
+     * Calling this when handling a
+     * {@link net.md_5.bungee.api.event.ServerConnectedEvent} may be the best
+     * place to do so as this event occurs after a FML handshake has completed,
+     * if any has occurred.
+     * </p>
+     *
+     * @return A {@link Map} of mods, where the key is the name of the mod, and
+     * the value is the version. Returns an empty list if the FML handshake has
+     * not occurred for this {@link ProxiedPlayer} yet.
+     */
+    Map<String, String> getModList();
 }