detect if client is offline using feedback instead of ntp signal

README.html

@@ -1159,16 +1159,16 @@ <h1 id="usage">Usage</h1>
 <code>ctrl-C fg ctrl-C</code> to terminate the image viewer, bring
 <code>uxplay</code> into the foreground, and terminate it too.</p>
 <p><strong>-reset n</strong> sets a limit of <em>n</em> consecutive
-timeout failures of the client to respond to ntp requests from the
-server (these are sent every 3 seconds to check if the client is still
-present, and synchronize with it). After <em>n</em> failures, the client
-will be presumed to be offline, and the connection will be reset to
-allow a new connection. The default value of <em>n</em> is 5; the value
-<em>n</em> = 0 means “no limit” on timeouts.</p>
+failures of the client to send feedback requests (these “heartbeat
+signals” are sent by the client once per second to ask for a response
+showing that the server is still online). After <em>n</em> missing
+signals, the client will be presumed to be offline, and the connection
+will be reset to allow a new connection. The default value of <em>n</em>
+is 15 seconds; the value <em>n</em> = 0 means “no limit”.</p>
 <p><strong>-nofreeze</strong> closes the video window after a reset due
-to ntp timeout (default is to leave window open to allow a smoother
-reconection to the same client). This option may be useful in fullscreen
-mode.</p>
+to client going offline (default is to leave window open to allow a
+smoother reconection to the same client). This option may be useful in
+fullscreen mode.</p>
 <p><strong>-nc</strong> maintains previous UxPlay &lt; 1.45 behavior
 that does <strong>not close</strong> the video window when the the
 client sends the “Stop Mirroring” signal. <em>This option is currently

README.md

@@ -1179,14 +1179,14 @@ uxplay was put into the background). To quit, use `ctrl-C fg ctrl-C` to
 terminate the image viewer, bring `uxplay` into the foreground, and
 terminate it too.
 
-**-reset n** sets a limit of *n* consecutive timeout failures of the
-client to respond to ntp requests from the server (these are sent every
-3 seconds to check if the client is still present, and synchronize with
-it). After *n* failures, the client will be presumed to be offline, and
+**-reset n** sets a limit of *n* consecutive failures of the
+client to send feedback requests (these "heartbeat signals" are sent by the client
+once per second to ask for a response showing that the server is still online).
+After *n* missing signals, the client will be presumed to be offline, and
 the connection will be reset to allow a new connection. The default
-value of *n* is 5; the value *n* = 0 means "no limit" on timeouts.
+value of *n* is 15 seconds; the value *n* = 0 means "no limit".
 
-**-nofreeze** closes the video window after a reset due to ntp timeout
+**-nofreeze** closes the video window after a reset due to client going offline
 (default is to leave window open to allow a smoother reconection to the
 same client). This option may be useful in fullscreen mode.
 

README.txt

@@ -1180,16 +1180,16 @@ uxplay was put into the background). To quit, use `ctrl-C fg ctrl-C` to
 terminate the image viewer, bring `uxplay` into the foreground, and
 terminate it too.
 
-**-reset n** sets a limit of *n* consecutive timeout failures of the
-client to respond to ntp requests from the server (these are sent every
-3 seconds to check if the client is still present, and synchronize with
-it). After *n* failures, the client will be presumed to be offline, and
-the connection will be reset to allow a new connection. The default
-value of *n* is 5; the value *n* = 0 means "no limit" on timeouts.
-
-**-nofreeze** closes the video window after a reset due to ntp timeout
-(default is to leave window open to allow a smoother reconection to the
-same client). This option may be useful in fullscreen mode.
+**-reset n** sets a limit of *n* consecutive failures of the client to
+send feedback requests (these "heartbeat signals" are sent by the client
+once per second to ask for a response showing that the server is still
+online). After *n* missing signals, the client will be presumed to be
+offline, and the connection will be reset to allow a new connection. The
+default value of *n* is 15 seconds; the value *n* = 0 means "no limit".
+
+**-nofreeze** closes the video window after a reset due to client going
+offline (default is to leave window open to allow a smoother reconection
+to the same client). This option may be useful in fullscreen mode.
 
 **-nc** maintains previous UxPlay \< 1.45 behavior that does **not
 close** the video window when the the client sends the "Stop Mirroring"

lib/raop.c

@@ -64,7 +64,6 @@ struct raop_s {
     uint8_t clientFPSdata;
 
     int audio_delay_micros;
-    int max_ntp_timeouts;
 
      /* for temporary storage of pin during pair-pin start */
      unsigned short pin;
@@ -554,7 +553,6 @@ raop_init(raop_callbacks_t *callbacks) {
     /* initialize switch for display of client's streaming data records */    
     raop->clientFPSdata = 0;
 
-    raop->max_ntp_timeouts = 0;
     raop->audio_delay_micros = 250000;
 
     raop->hls_support = false;
@@ -662,9 +660,6 @@ int raop_set_plist(raop_t *raop, const char *plist_item, const int value) {
     } else if (strcmp(plist_item, "clientFPSdata") == 0) {
         raop->clientFPSdata = (value ? 1 : 0);
         if ((int) raop->clientFPSdata  != value) retval = 1;
-    } else if (strcmp(plist_item, "max_ntp_timeouts") == 0) {
-        raop->max_ntp_timeouts = (value > 0 ? value : 0);
-        if (raop->max_ntp_timeouts != value) retval = 1;
     } else if (strcmp(plist_item, "audio_delay_micros") == 0) {
         if (value >= 0 && value <= 10 * SECOND_IN_USECS) {     
             raop->audio_delay_micros = value;

lib/raop.h

@@ -67,11 +67,12 @@ struct raop_callbacks_s {
     void  (*video_process)(void *cls, raop_ntp_t *ntp, video_decode_struct *data);
     void  (*video_pause)(void *cls);
     void  (*video_resume)(void *cls);
+    void  (*conn_feedback) (void *cls);
 
     /* Optional but recommended callback functions */
     void  (*conn_init)(void *cls);
     void  (*conn_destroy)(void *cls);
-    void  (*conn_reset) (void *cls, int timeouts, bool reset_video);
+    void  (*conn_reset) (void *cls);
     void  (*conn_teardown)(void *cls, bool *teardown_96, bool *teardown_110 );
     void  (*audio_flush)(void *cls);
     void  (*video_flush)(void *cls);

lib/raop_handlers.h

@@ -742,7 +742,7 @@ raop_handler_setup(raop_conn_t *conn,
         }
         conn->raop_ntp = raop_ntp_init(conn->raop->logger, &conn->raop->callbacks, remote,
                                        conn->remotelen, (unsigned short) timing_rport, &time_protocol);
-        raop_ntp_start(conn->raop_ntp, &timing_lport, conn->raop->max_ntp_timeouts);
+        raop_ntp_start(conn->raop_ntp, &timing_lport);
         conn->raop_rtp = raop_rtp_init(conn->raop->logger, &conn->raop->callbacks, conn->raop_ntp,
                                        remote, conn->remotelen, aeskey, aesiv);
         conn->raop_rtp_mirror = raop_rtp_mirror_init(conn->raop->logger, &conn->raop->callbacks,
@@ -983,6 +983,8 @@ raop_handler_feedback(raop_conn_t *conn,
                       char **response_data, int *response_datalen)
 {
     logger_log(conn->raop->logger, LOGGER_DEBUG, "raop_handler_feedback");
+    /* register receipt of client's "heartbeat" signal  */
+    conn->raop->callbacks.conn_feedback(conn->raop->callbacks.cls);
 }
 
 static void

lib/raop_ntp.c

@@ -58,8 +58,6 @@ struct raop_ntp_s {
     logger_t *logger;
     raop_callbacks_t callbacks;
 
-    int max_ntp_timeouts;
-
     thread_handle_t thread;
     mutex_handle_t run_mutex;
 
@@ -94,6 +92,8 @@ struct raop_ntp_s {
     int tsock;
 
     timing_protocol_t time_protocol;
+    bool client_time_received;
+
 };
 
 
@@ -153,6 +153,7 @@ raop_ntp_t *raop_ntp_init(logger_t *logger, raop_callbacks_t *callbacks, const c
     raop_ntp->logger = logger;
     memcpy(&raop_ntp->callbacks, callbacks, sizeof(raop_callbacks_t));    
     raop_ntp->timing_rport = timing_rport;
+    raop_ntp->client_time_received = false;
 
     if (raop_ntp_parse_remote(raop_ntp, remote, remote_addr_len) < 0) {
         free(raop_ntp);
@@ -274,8 +275,6 @@ raop_ntp_thread(void *arg)
     };
     raop_ntp_data_t data_sorted[RAOP_NTP_DATA_COUNT];
     const unsigned  two_pow_n[RAOP_NTP_DATA_COUNT] = {2, 4, 8, 16, 32, 64, 128, 256};
-    int timeout_counter = 0;
-    bool conn_reset = false;
     bool logger_debug = (logger_get_level(raop_ntp->logger) >= LOGGER_DEBUG);
 
     while (1) {
@@ -308,20 +307,15 @@ raop_ntp_thread(void *arg)
             // Read response
             response_len = recvfrom(raop_ntp->tsock, (char *)response, sizeof(response), 0, NULL, NULL);
             if (response_len < 0) {
-                timeout_counter++;
                 char time[30];
-                int level = (timeout_counter == 1 ? LOGGER_DEBUG : LOGGER_ERR);
                 ntp_timestamp_to_time(send_time, time, sizeof(time));
-                logger_log(raop_ntp->logger, level, "raop_ntp receive timeout %d (limit %d) (request sent %s)",
-                           timeout_counter, raop_ntp->max_ntp_timeouts, time);
-                if (timeout_counter ==  raop_ntp->max_ntp_timeouts) {
-                    conn_reset = true;   /* client is no longer responding */
-                    break;
-                }
+                logger_log(raop_ntp->logger, LOGGER_DEBUG , "raop_ntp receive timeout (request sent %s)", time);
 	    } else {
+                if (!raop_ntp->client_time_received) {
+                    raop_ntp->client_time_received = true;
+                }
                 //local time of the server when the NTP response packet returns
                 int64_t t3 = (int64_t) raop_ntp_get_local_time(raop_ntp);
-                timeout_counter = 0;
 
                 // Local time of the server when the NTP request packet leaves the server
                 int64_t t0 = (int64_t) byteutils_get_ntp_timestamp(response, 8);
@@ -391,23 +385,18 @@ raop_ntp_thread(void *arg)
     MUTEX_UNLOCK(raop_ntp->run_mutex);
 
     logger_log(raop_ntp->logger, LOGGER_DEBUG, "raop_ntp exiting thread");
-    if (conn_reset && raop_ntp->callbacks.conn_reset) {
-        const bool video_reset = false;   /* leave "frozen video" in place */
-        raop_ntp->callbacks.conn_reset(raop_ntp->callbacks.cls, timeout_counter, video_reset);
-    }
     return 0;
 }
 
 void
-raop_ntp_start(raop_ntp_t *raop_ntp, unsigned short *timing_lport, int max_ntp_timeouts)
+raop_ntp_start(raop_ntp_t *raop_ntp, unsigned short *timing_lport)
 {
     logger_log(raop_ntp->logger, LOGGER_DEBUG, "raop_ntp starting time");
     int use_ipv6 = 0;
 
     assert(raop_ntp);
     assert(timing_lport);
 
-    raop_ntp->max_ntp_timeouts = max_ntp_timeouts;
     raop_ntp->timing_lport = *timing_lport;
 
     MUTEX_LOCK(raop_ntp->run_mutex);

lib/raop_ntp.h

@@ -27,7 +27,7 @@ typedef struct raop_ntp_s raop_ntp_t;
 
 typedef enum timing_protocol_e { NTP, TP_NONE, TP_OTHER, TP_UNSPECIFIED } timing_protocol_t;
 
-void raop_ntp_start(raop_ntp_t *raop_ntp, unsigned short *timing_lport, int max_ntp_timeouts);
+void raop_ntp_start(raop_ntp_t *raop_ntp, unsigned short *timing_lport);
 
 void raop_ntp_stop(raop_ntp_t *raop_ntp);
 

lib/raop_rtp_mirror.c

@@ -804,9 +804,8 @@ raop_rtp_mirror_thread(void *arg)
     MUTEX_UNLOCK(raop_rtp_mirror->run_mutex);
 
     logger_log(raop_rtp_mirror->logger, LOGGER_DEBUG, "raop_rtp_mirror exiting TCP thread");
-    if (conn_reset && raop_rtp_mirror->callbacks.conn_reset) {
-        const bool video_reset = false;   /* leave "frozen video" showing */
-        raop_rtp_mirror->callbacks.conn_reset(raop_rtp_mirror->callbacks.cls, 0, video_reset);
+    if (conn_reset&& raop_rtp_mirror->callbacks.conn_reset) {
+        raop_rtp_mirror->callbacks.conn_reset(raop_rtp_mirror->callbacks.cls);
     }
 
     if (unsupported_codec) {

uxplay.1

@@ -106,7 +106,7 @@ UxPlay 1.71: An open\-source AirPlay mirroring (+ audio streaming) server:
 .TP
 \fB\-ca\fI fn \fR   In Airplay Audio (ALAC) mode, write cover-art to file fn.
 .TP
-\fB\-reset\fR n  Reset after 3n seconds client silence (default 5, 0=never).
+\fB\-reset\fR n  Reset after n seconds client silence (default n=15, 0=never).
 .TP
 \fB\-nofreeze\fR Do NOT leave frozen screen in place after reset.
 .TP

uxplay.cpp

@@ -70,7 +70,7 @@
 #define DEFAULT_DEBUG_LOG false
 #define LOWEST_ALLOWED_PORT 1024
 #define HIGHEST_PORT 65535
-#define NTP_TIMEOUT_LIMIT 5
+#define MISSED_FEEDBACK_LIMIT 15
 #define BT709_FIX "capssetter caps=\"video/x-h264, colorimetry=bt709\""
 #define SRGB_FIX  " ! video/x-raw,colorimetry=sRGB,format=RGB  ! "
 #ifdef FULL_RANGE_RGB_FIX
@@ -104,7 +104,6 @@ static std::string video_parser = "h264parse";
 static std::string video_decoder = "decodebin";
 static std::string video_converter = "videoconvert";
 static bool show_client_FPS_data = false;
-static unsigned int max_ntp_timeouts = NTP_TIMEOUT_LIMIT;
 static FILE *video_dumpfile = NULL;
 static std::string video_dumpfile_name = "videodump";
 static int video_dump_limit = 0;
@@ -156,6 +155,8 @@ static std::string url = "";
 static guint gst_x11_window_id = 0;
 static guint gst_hls_position_id = 0;
 static bool preserve_connections = false;
+static guint missed_feedback_limit = MISSED_FEEDBACK_LIMIT;
+static guint missed_feedback = 0;
 
 /* logging */
 
@@ -365,6 +366,28 @@ static void dump_video_to_file(unsigned char *data, int datalen) {
     }
 }
 
+static gboolean feedback_callback(gpointer loop) {
+    if (open_connections) {
+        if (missed_feedback_limit && missed_feedback > missed_feedback_limit) {
+            LOGI("***ERROR lost connection with client (network problem?)");
+            LOGI("%u missed client feedback signals exceeds limit of %u", missed_feedback, missed_feedback_limit);
+            LOGI("   Sometimes the network connection may recover after a longer delay:\n"
+                 "   the default limit n = %d seconds, can be changed with the \"-reset n\" option", MISSED_FEEDBACK_LIMIT);
+            if (!nofreeze) {
+                close_window = false; /* leave "frozen" window open if reset_video is false */
+            }
+	    raop_stop(raop);
+	    reset_loop = true;	    
+        } else if (missed_feedback > 2) {
+            LOGE("%u missed client feedback signals (expected once per second); client may be offline", missed_feedback);
+        }
+        missed_feedback++;
+    } else {
+        missed_feedback = 0;
+    }
+    return TRUE;
+}
+
 static gboolean reset_callback(gpointer loop) {
     if (reset_loop) {
         g_main_loop_quit((GMainLoop *) loop);
@@ -435,6 +458,8 @@ static void main_loop()  {
             gst_bus_watch_id[i] = (guint) video_renderer_listen((void *)loop, i);
         }
     }
+    missed_feedback = 0;
+    guint feedback_watch_id = g_timeout_add_seconds(1, (GSourceFunc) feedback_callback, (gpointer) loop);
     guint reset_watch_id = g_timeout_add(100, (GSourceFunc) reset_callback, (gpointer) loop);
     guint video_reset_watch_id = g_timeout_add(100, (GSourceFunc) video_reset_callback, (gpointer) loop);
     guint sigterm_watch_id = g_unix_signal_add(SIGTERM, (GSourceFunc) sigterm_callback, (gpointer) loop);
@@ -449,6 +474,7 @@ static void main_loop()  {
     if (sigterm_watch_id > 0) g_source_remove(sigterm_watch_id);
     if (reset_watch_id > 0) g_source_remove(reset_watch_id);
     if (video_reset_watch_id > 0) g_source_remove(video_reset_watch_id);
+    if (feedback_watch_id > 0) g_source_remove(feedback_watch_id);
     g_main_loop_unref(loop);
 }    
 
@@ -657,7 +683,7 @@ static void print_info (char *name) {
     printf("-as 0     (or -a)  Turn audio off, streamed video only\n");
     printf("-al x     Audio latency in seconds (default 0.25) reported to client.\n");
     printf("-ca <fn>  In Airplay Audio (ALAC) mode, write cover-art to file <fn>\n");
-    printf("-reset n  Reset after 3n seconds client silence (default %d, 0=never)\n", NTP_TIMEOUT_LIMIT);
+    printf("-reset n  Reset after n seconds of client silence (default n=%d, 0=never)\n", MISSED_FEEDBACK_LIMIT);
     printf("-nofreeze Do NOT leave frozen screen in place after reset\n");
     printf("-nc       Do NOT Close video window when client stops mirroring\n");
     printf("-nohold   Drop current connection when new client connects.\n");
@@ -739,7 +765,7 @@ static bool get_value (const char *str, unsigned int *n) {
 static bool get_ports (int nports, std::string option, const char * value, unsigned short * const port) {
     /*valid entries are comma-separated values port_1,port_2,...,port_r, 0 < r <= nports */
     /*where ports are distinct, and are in the allowed range.                            */
-    /*missing values are consecutive to last given value (at least one value needed).    */
+    /*missed values are consecutive to last given value (at least one value needed).    */
     char *end;
     unsigned long l;
     std::size_t pos;
@@ -1020,9 +1046,10 @@ static void parse_arguments (int argc, char *argv[]) {
 	} else if (arg == "-FPSdata") {
             show_client_FPS_data = true;
         } else if (arg == "-reset") {
-            max_ntp_timeouts = 0;
-            if (!get_value(argv[++i], &max_ntp_timeouts)) {
-                fprintf(stderr, "invalid \"-reset %s\"; -reset n must have n >= 0,  default n = %d\n", argv[i], NTP_TIMEOUT_LIMIT);
+            /* now using feedback  (every 1 sec ) instead of ntp timeouts (every 3 secs) to detect offline client and reset connections */
+            fprintf(stderr,"*** NOTE CHANGE: -reset n now means reset n seconds (not 3n seconds) after client goes offline\n");	  
+            if (!get_value(argv[++i], &missed_feedback_limit)) {
+                fprintf(stderr, "invalid \"-reset %s\"; -reset n must have n >= 0,  default n = %d seconds\n", argv[i], MISSED_FEEDBACK_LIMIT);
                 exit(1);
             }
         } else if (arg == "-vdmp") {
@@ -1587,15 +1614,15 @@ extern "C" void conn_destroy (void *cls) {
     }
 }
 
-extern "C" void conn_reset (void *cls, int timeouts, bool reset_video) {
+extern "C" void conn_feedback (void *cls) {
+    /* received client heartbeat signal: connection still exists */
+    missed_feedback = 0;
+}
+
+extern "C" void conn_reset (void *cls) {
     LOGI("***ERROR lost connection with client (network problem?)");
-    if (timeouts) {
-        LOGI("   Client no-response limit of %d timeouts (%d seconds) reached:", timeouts, 3*timeouts);
-        LOGI("   Sometimes the network connection may recover after a longer delay:\n"
-             "   the default timeout limit n = %d can be changed with the \"-reset n\" option", NTP_TIMEOUT_LIMIT);
-    }
     if (!nofreeze) {
-        close_window = reset_video;    /* leave "frozen" window open if reset_video is false */
+        close_window = false;    /* leave "frozen" window open */
     }
     raop_stop(raop);
     reset_loop = true;
@@ -1931,6 +1958,7 @@ static int start_raop_server (unsigned short display[5], unsigned short tcp[3],
     raop_cbs.conn_init = conn_init;
     raop_cbs.conn_destroy = conn_destroy;
     raop_cbs.conn_reset = conn_reset;
+    raop_cbs.conn_feedback = conn_feedback;
     raop_cbs.conn_teardown = conn_teardown;
     raop_cbs.audio_process = audio_process;
     raop_cbs.video_process = video_process;
@@ -1981,7 +2009,6 @@ static int start_raop_server (unsigned short display[5], unsigned short tcp[3],
     if (display[4]) raop_set_plist(raop, "overscanned", (int) display[4]);
 
     if (show_client_FPS_data) raop_set_plist(raop, "clientFPSdata", 1);
-    raop_set_plist(raop, "max_ntp_timeouts", max_ntp_timeouts);
     if (audiodelay >= 0) raop_set_plist(raop, "audio_delay_micros", audiodelay);
     if (require_password) raop_set_plist(raop, "pin", (int) pin);
     if (hls_support) raop_set_plist(raop, "hls", 1);