Add wildcard forced hosts (fix #1587)

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -99,6 +99,7 @@
 import com.velocitypowered.proxy.tablist.KeyedVelocityTabList;
 import com.velocitypowered.proxy.tablist.VelocityTabList;
 import com.velocitypowered.proxy.tablist.VelocityTabListLegacy;
+import com.velocitypowered.proxy.util.AddressUtil;
 import com.velocitypowered.proxy.util.ClosestLocaleMatcher;
 import com.velocitypowered.proxy.util.DurationUtils;
 import com.velocitypowered.proxy.util.TranslatableMapper;
@@ -111,6 +112,7 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
@@ -890,8 +892,17 @@ private Optional<RegisteredServer> getNextServerToTry(@Nullable RegisteredServer
       String virtualHostStr = getVirtualHost().map(InetSocketAddress::getHostString)
           .orElse("")
           .toLowerCase(Locale.ROOT);
-      serversToTry = server.getConfiguration().getForcedHosts().getOrDefault(virtualHostStr,
-          Collections.emptyList());
+      serversToTry = server.getConfiguration().getForcedHosts().getOrDefault(
+              virtualHostStr,
+              server.getConfiguration()
+                      .getForcedHosts()
+                      .entrySet()
+                      .stream()
+                      .filter(entry -> AddressUtil.isHostMatchingPattern(entry.getKey(), virtualHostStr))
+                      .map(Map.Entry::getValue)
+                      .findFirst()
+                      .orElse(Collections.emptyList())
+      );
     }
 
     if (serversToTry.isEmpty()) {

proxy/src/main/java/com/velocitypowered/proxy/connection/util/ServerListPingHandler.java

@@ -28,11 +28,13 @@
 import com.velocitypowered.proxy.config.PingPassthroughMode;
 import com.velocitypowered.proxy.config.VelocityConfiguration;
 import com.velocitypowered.proxy.server.VelocityRegisteredServer;
+import com.velocitypowered.proxy.util.AddressUtil;
 import java.net.InetSocketAddress;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.stream.Collectors;
@@ -175,7 +177,16 @@ public CompletableFuture<ServerPing> getInitialPing(VelocityInboundConnection co
           .map(str -> str.toLowerCase(Locale.ROOT))
           .orElse("");
       List<String> serversToTry = server.getConfiguration().getForcedHosts().getOrDefault(
-          virtualHostStr, server.getConfiguration().getAttemptConnectionOrder());
+              virtualHostStr,
+              server.getConfiguration()
+                      .getForcedHosts()
+                      .entrySet()
+                      .stream()
+                      .filter(entry -> AddressUtil.isHostMatchingPattern(entry.getKey(), virtualHostStr))
+                      .map(Map.Entry::getValue)
+                      .findFirst()
+                      .orElse(server.getConfiguration().getAttemptConnectionOrder())
+      );
       return attemptPingPassthrough(connection, passthroughMode, serversToTry, shownVersion, virtualHostStr);
     }
   }

proxy/src/main/java/com/velocitypowered/proxy/util/AddressUtil.java

@@ -74,4 +74,37 @@ public static InetSocketAddress parseAndResolveAddress(String ip) {
     int port = uri.getPort() == -1 ? DEFAULT_MINECRAFT_PORT : uri.getPort();
     return new InetSocketAddress(uri.getHost(), port);
   }
+
+  /**
+   * Tests whether a host matches a pattern whose labels may be the
+   * wildcard {@code "*"}. Each {@code "*"} matches exactly one label; all other
+   * labels match case-insensitively.
+   *
+   * @param pattern the pattern to match against, for example, {@code *.soulrealms.net}
+   * @param host the virtual host to test, for example, {@code play.soulrealms.net}
+   * @return true if the host matches the pattern, false otherwise
+   */
+  public static boolean isHostMatchingPattern(String pattern, String host) {
+    if (host == null || pattern == null) {
+      return false;
+    }
+
+    String[] patternDomains = pattern.split("\\.");
+    String[] strDomains = host.split("\\.");
+
+    if (patternDomains.length != strDomains.length) {
+      return false;
+    }
+
+    for (int i = 0; patternDomains.length > i; i++) {
+      String patternDomain = patternDomains[i];
+      String strDomain = strDomains[i];
+
+      if (!patternDomain.equals("*") && !strDomain.equalsIgnoreCase(patternDomain)) {
+        return false;
+      }
+    }
+
+    return true;
+  }
 }

proxy/src/test/java/com/velocitypowered/proxy/connection/client/ForcedHostsTest.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2018-2021 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.connection.client;
+
+import com.velocitypowered.proxy.util.AddressUtil;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+class ForcedHostsTest {
+  @Test
+  void testIsHostMatchingPattern() {
+    Assertions.assertTrue(AddressUtil.isHostMatchingPattern("*.miscpvp.org", "play.miscpvp.org"));
+    Assertions.assertTrue(AddressUtil.isHostMatchingPattern("*.miscpvp.org", "yt.miscpvp.org"));
+    Assertions.assertTrue(AddressUtil.isHostMatchingPattern("*.miscpvp.org", "ip.miscpvp.org"));
+    Assertions.assertTrue(AddressUtil.isHostMatchingPattern("test.*.miscpvp.org", "test.example.miscpvp.org"));
+    Assertions.assertFalse(AddressUtil.isHostMatchingPattern("*.miscpvp.org", "test.example.miscpvp.org"));
+    Assertions.assertFalse(AddressUtil.isHostMatchingPattern("*.miscpvp.org", "miscpvp.org"));
+    Assertions.assertFalse(AddressUtil.isHostMatchingPattern("miscpvp.minehunt.gg", "ip.miscpvp.org"));
+  }
+}