unmask ep3 commands on proxy server

src/CommandFormats.hh

@@ -2099,6 +2099,12 @@ struct C_SetBlockedSenders_BB_C6 : C_SetBlockedSenders_C6<28> { } __packed__;
 // This command is not valid on Episode 3 Trial Edition.
 // header.flag determines the client's registration state - 1 if the client is
 // registered for the tournament, 0 if not.
+// This command controls what's shown in the Check Tactics pane in the pause
+// menu. If the client is registered (header.flag==1), the option is enabled and
+// the bracket data in the command is shown there, and a third pane on the
+// Status item shows the other information (tournament name, ship name, and
+// start time). If the client is not registered, the Check Tactics option is
+// disabled and the Status item has only two panes.
 
 struct S_ConfirmTournamentEntry_GC_Ep3_CC {
   ptext<char, 0x40> tournament_name;

src/ProxyCommands.cc

@@ -890,7 +890,21 @@ static HandlerResult S_6x(shared_ptr<ServerState>,
     }
   }
 
+  bool modified = false;
   if (!data.empty()) {
+    // Unmask any masked Episode 3 commands from the server
+    if ((session.version == GameVersion::GC) && (data.size() > 8) &&
+        ((static_cast<uint8_t>(data[0]) == 0xB3) ||
+         (static_cast<uint8_t>(data[0]) == 0xB4) ||
+         (static_cast<uint8_t>(data[0]) == 0xB5))) {
+      const auto& header = check_size_t<G_CardBattleCommandHeader>(
+          data, sizeof(G_CardBattleCommandHeader), 0xFFFF);
+      if (header.mask_key) {
+        set_mask_for_ep3_game_command(data.data(), data.size(), 0);
+        modified = true;
+      }
+    }
+
     if (data[0] == 0x46) {
       const auto& cmd = check_size_t<G_AttackFinished_6x46>(data,
           offsetof(G_AttackFinished_6x46, entries),
@@ -962,7 +976,7 @@ static HandlerResult S_6x(shared_ptr<ServerState>,
     }
   }
 
-  return HandlerResult::Type::FORWARD;
+  return modified ? HandlerResult::Type::MODIFIED : HandlerResult::Type::FORWARD;
 }
 
 template <typename T>