add $ping command

README.md

@@ -271,6 +271,7 @@ Some commands only work on the game server and not on the proxy server. The chat
 
 * Information commands
     * `$li`: Shows basic information about the lobby or game you're in. If you're on the proxy server, shows information about your connection instead (remote Guild Card number, client ID, etc.).
+    * `$ping` (game server only): Shows round-trip ping time from the server to you.
     * `$what` (game server only): Shows the type, name, and stats of the nearest item on the ground.
     * `$matcount` (game server only): Shows how many of each type of material you've used.
 

src/ChatCommands.cc

@@ -159,6 +159,11 @@ static void server_command_lobby_info(shared_ptr<Client> c, const std::string&)
   send_text_message(c, join(lines, "\n"));
 }
 
+static void server_command_ping(shared_ptr<Client> c, const std::string&) {
+  c->ping_start_time = now();
+  send_command(c, 0x1D, 0x00);
+}
+
 static void proxy_command_lobby_info(shared_ptr<ProxyServer::LinkedSession> ses, const std::string&) {
   string msg;
   // On non-masked-GC sessions (BB), there is no remote Guild Card number, so we
@@ -1598,6 +1603,7 @@ static const unordered_map<string, ChatCommandDefinition> chat_commands({
     {"$password", {server_command_password, nullptr}},
     {"$patch", {server_command_patch, proxy_command_patch}},
     {"$persist", {server_command_persist, nullptr}},
+    {"$ping", {server_command_ping, nullptr}},
     {"$playrec", {server_command_playrec, nullptr}},
     {"$rand", {server_command_rand, proxy_command_rand}},
     {"$saverec", {server_command_saverec, nullptr}},

src/Client.cc

@@ -147,6 +147,7 @@ Client::Client(
       should_send_to_lobby_server(false),
       should_send_to_proxy_server(false),
       bb_connection_phase(0xFF),
+      ping_start_time(0),
       sub_version(-1),
       x(0.0f),
       z(0.0f),

src/Client.hh

@@ -166,6 +166,7 @@ struct Client : public std::enable_shared_from_this<Client> {
   std::shared_ptr<XBNetworkLocation> xb_netloc;
   parray<le_uint32_t, 3> xb_9E_unknown_a1a;
   uint8_t bb_connection_phase;
+  uint64_t ping_start_time;
 
   // Patch server
   std::vector<PatchFileChecksumRequest> patch_file_checksum_requests;

src/ReceiveCommands.cc

@@ -322,6 +322,15 @@ void on_disconnect(shared_ptr<Client> c) {
 
 ////////////////////////////////////////////////////////////////////////////////
 
+static void on_1D(shared_ptr<Client> c, uint16_t, uint32_t, string&) {
+  if (c->ping_start_time) {
+    uint64_t ping_usecs = now() - c->ping_start_time;
+    c->ping_start_time = 0;
+    double ping_ms = static_cast<double>(ping_usecs) / 1000.0;
+    send_text_message_printf(c, "To server: %gms", ping_ms);
+  }
+}
+
 static void on_05_XB(shared_ptr<Client> c, uint16_t, uint32_t, string&) {
   // The Xbox Live service doesn't close the TCP connection when the player
   // chooses Quit Game, so we manually disconnect the client when they send this
@@ -4360,7 +4369,7 @@ static on_command_t handlers[0x100][6] = {
   /* 1A */ {nullptr, nullptr,        nullptr,     nullptr,        nullptr,        nullptr},
   /* 1B */ {nullptr, nullptr,        nullptr,     nullptr,        nullptr,        nullptr},
   /* 1C */ {nullptr, nullptr,        nullptr,     nullptr,        nullptr,        nullptr},
-  /* 1D */ {nullptr, on_ignored,     on_ignored,  on_ignored,     on_ignored,     on_ignored},
+  /* 1D */ {nullptr, on_1D,          on_1D,       on_1D,          on_1D,          on_1D},
   /* 1E */ {nullptr, nullptr,        nullptr,     nullptr,        nullptr,        nullptr},
   /* 1F */ {nullptr, on_1F,          on_1F,       nullptr,        nullptr,        nullptr},
   //        PATCH    DC              PC           GC              XB              BB