add udp keepalive

src/discord/voiceclient.cpp

@@ -188,6 +188,7 @@ DiscordVoiceClient::~DiscordVoiceClient() {
 void DiscordVoiceClient::Start() {
     m_ws.StartConnection("wss://" + m_endpoint + "/?v=7");
     m_heartbeat_waiter.revive();
+    m_keepalive_waiter.revive();
 }
 
 void DiscordVoiceClient::Stop() {
@@ -196,6 +197,8 @@ void DiscordVoiceClient::Stop() {
         m_udp.Stop();
         m_heartbeat_waiter.kill();
         if (m_heartbeat_thread.joinable()) m_heartbeat_thread.join();
+        m_keepalive_waiter.kill();
+        if (m_keepalive_thread.joinable()) m_keepalive_thread.join();
         m_connected = false;
         m_signal_disconnected.emit();
     }
@@ -271,6 +274,7 @@ void DiscordVoiceClient::HandleGatewayReady(const VoiceGatewayMessage &m) {
     printf("connect to %s:%u ssrc %u\n", m_ip.c_str(), m_port, m_ssrc);
 
     m_udp.Connect(m_ip, m_port);
+    m_keepalive_thread = std::thread(&DiscordVoiceClient::KeepaliveThread, this);
 
     Discovery();
 }
@@ -385,6 +389,18 @@ void DiscordVoiceClient::HeartbeatThread() {
     }
 }
 
+void DiscordVoiceClient::KeepaliveThread() {
+    while (true) {
+        if (!m_keepalive_waiter.wait_for(std::chrono::seconds(10)))
+            break;
+
+        if (IsConnected()) {
+            const static uint8_t KEEPALIVE[] = { 0x13, 0x37 };
+            m_udp.Send(KEEPALIVE, sizeof(KEEPALIVE));
+        }
+    }
+}
+
 DiscordVoiceClient::type_signal_disconnected DiscordVoiceClient::signal_connected() {
     return m_signal_connected;
 }

src/discord/voiceclient.hpp

@@ -5,8 +5,8 @@
 #include "snowflake.hpp"
 #include "waiter.hpp"
 #include "websocket.hpp"
-#include <optional>
 #include <mutex>
+#include <optional>
 #include <queue>
 #include <string>
 #include <glibmm/dispatcher.h>
@@ -211,6 +211,7 @@ private:
     void OnUDPData(std::vector<uint8_t> data);
 
     void HeartbeatThread();
+    void KeepaliveThread();
 
     std::string m_session_id;
     std::string m_endpoint;
@@ -242,6 +243,9 @@ private:
     Waiter m_heartbeat_waiter;
     std::thread m_heartbeat_thread;
 
+    Waiter m_keepalive_waiter;
+    std::thread m_keepalive_thread;
+
     std::array<uint8_t, 1275> m_opus_buffer;
 
     std::atomic<bool> m_connected = false;