tcpclientsrc: Expose connection stats as property

Unfortunately the OS takes care of bad connections for us, so we can't
get the stats in a platform-independent way. Count total bytes received
as well, platform-independently.

gst/tcp/gsttcpclientsrc.c

@@ -43,6 +43,16 @@
 #include "config.h"
 #endif
 
+/* macOS and iOS have the .h files but the tcp_info struct is private API */
+#if defined(HAVE_NETINET_TCP_H) && defined(HAVE_NETINET_IN_H) && defined(HAVE_SYS_SOCKET_H)
+#include <netinet/tcp.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#if defined(TCP_INFO)
+#define HAVE_SOCKET_METRIC_HEADERS
+#endif
+#endif
+
 #include <gst/gst-i18n-plugin.h>
 #include "gsttcpclientsrc.h"
 #include "gsttcp.h"
@@ -65,7 +75,8 @@ enum
   PROP_0,
   PROP_HOST,
   PROP_PORT,
-  PROP_TIMEOUT
+  PROP_TIMEOUT,
+  PROP_STATS,
 };
 
 #define gst_tcp_client_src_parent_class parent_class
@@ -88,6 +99,7 @@ static void gst_tcp_client_src_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec);
 static void gst_tcp_client_src_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec);
+static GstStructure *gst_tcp_client_src_get_stats (GstTCPClientSrc * src);
 
 static void
 gst_tcp_client_src_class_init (GstTCPClientSrcClass * klass)
@@ -128,6 +140,30 @@ gst_tcp_client_src_class_init (GstTCPClientSrcClass * klass)
           G_MAXUINT, TCP_DEFAULT_TIMEOUT,
           G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
+  /**
+   * GstTCPClientSrc::stats:
+   *
+   * Sends a GstStructure with statistics. We count bytes-received in a
+   * platform-independent way and the rest via the tcp_info struct, if it's
+   * available. The OS takes care of the TCP layer for us so we can't know it
+   * from here.
+   *
+   * Struct members:
+   *
+   * bytes-received (uint64): Total bytes received (platform-independent)
+   * reordering (uint): Amount of reordering (linux-specific)
+   * unacked (uint): Un-acked packets (linux-specific)
+   * sacked (uint): Selective acked packets (linux-specific)
+   * lost (uint): Lost packets (linux-specific)
+   * retrans (uint): Retransmits (linux-specific)
+   * fackets (uint): Forward acknowledgement (linux-specific)
+   *
+   * Since: 1.18
+   */
+  g_object_class_install_property (gobject_class, PROP_STATS,
+      g_param_spec_boxed ("stats", "Stats", "Retrieve a statistics structure",
+          GST_TYPE_STRUCTURE, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+
   gst_element_class_add_static_pad_template (gstelement_class, &srctemplate);
 
   gst_element_class_set_static_metadata (gstelement_class,
@@ -172,6 +208,7 @@ gst_tcp_client_src_finalize (GObject * gobject)
   this->socket = NULL;
   g_free (this->host);
   this->host = NULL;
+  gst_clear_structure (&this->stats);
 
   G_OBJECT_CLASS (parent_class)->finalize (gobject);
 }
@@ -278,6 +315,7 @@ gst_tcp_client_src_create (GstPushSrc * psrc, GstBuffer ** outbuf)
     ret = GST_FLOW_OK;
     gst_buffer_unmap (*outbuf, &map);
     gst_buffer_resize (*outbuf, 0, rret);
+    src->bytes_received += read;
 
     GST_LOG_OBJECT (src,
         "Returning buffer from _get of size %" G_GSIZE_FORMAT ", ts %"
@@ -363,6 +401,9 @@ gst_tcp_client_src_get_property (GObject * object, guint prop_id,
     case PROP_TIMEOUT:
       g_value_set_uint (value, tcpclientsrc->timeout);
       break;
+    case PROP_STATS:
+      g_value_take_boxed (value, gst_tcp_client_src_get_stats (tcpclientsrc));
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -379,6 +420,9 @@ gst_tcp_client_src_start (GstBaseSrc * bsrc)
   GSocketAddress *saddr;
   GResolver *resolver;
 
+  src->bytes_received = 0;
+  gst_clear_structure (&src->stats);
+
   /* look up name if we need to */
   addr = g_inet_address_new_from_string (src->host);
   if (!addr) {
@@ -480,6 +524,8 @@ gst_tcp_client_src_stop (GstBaseSrc * bsrc)
   if (src->socket) {
     GST_DEBUG_OBJECT (src, "closing socket");
 
+    src->stats = gst_tcp_client_src_get_stats (src);
+
     if (!g_socket_close (src->socket, &err)) {
       GST_ERROR_OBJECT (src, "Failed to close socket: %s", err->message);
       g_clear_error (&err);
@@ -517,3 +563,38 @@ gst_tcp_client_src_unlock_stop (GstBaseSrc * bsrc)
 
   return TRUE;
 }
+
+static GstStructure *
+gst_tcp_client_src_get_stats (GstTCPClientSrc * src)
+{
+  GstStructure *s;
+
+  /* we can't get the values post stop so just return the saved ones */
+  if (src->stats)
+    return gst_structure_copy (src->stats);
+
+  s = gst_structure_new ("GstTCPClientSrcStats",
+      "bytes-received", G_TYPE_UINT64, src->bytes_received, NULL);
+
+#ifdef HAVE_SOCKET_METRIC_HEADERS
+  if (src->socket) {
+    struct tcp_info info;
+    socklen_t info_len = sizeof info;
+    int fd;
+
+    fd = g_socket_get_fd (src->socket);
+
+    if (getsockopt (fd, IPPROTO_TCP, TCP_INFO, &info, &info_len) == 0) {
+      gst_structure_set (s,
+          "reordering", G_TYPE_UINT, info.tcpi_reordering,
+          "unacked", G_TYPE_UINT, info.tcpi_unacked,
+          "sacked", G_TYPE_UINT, info.tcpi_sacked,
+          "lost", G_TYPE_UINT, info.tcpi_lost,
+          "retrans", G_TYPE_UINT, info.tcpi_retrans,
+          "fackets", G_TYPE_UINT, info.tcpi_fackets, NULL);
+    }
+  }
+#endif
+
+  return s;
+}

gst/tcp/gsttcpclientsrc.h

@@ -60,6 +60,9 @@ struct _GstTCPClientSrc {
   /* socket */
   GSocket *socket;
   GCancellable *cancellable;
+
+  guint64 bytes_received;
+  GstStructure *stats;
 };
 
 struct _GstTCPClientSrcClass {

meson.build

@@ -112,6 +112,8 @@ check_headers = [
   ['HAVE_EMMINTRIN_H', 'emmintrin.h'],
   ['HAVE_INTTYPES_H', 'inttypes.h'],
   ['HAVE_MEMORY_H', 'memory.h'],
+  ['HAVE_NETINET_IN_H', 'netinet/in.h'],
+  ['HAVE_NETINET_TCP_H', 'netinet/tcp.h'],
   ['HAVE_PROCESS_H', 'process.h'],
   ['HAVE_SMMINTRIN_H', 'smmintrin.h'],
   ['HAVE_STDINT_H', 'stdint.h'],