Add support for droping packets when using TCP and the bandwidth is too slow for the data output. The queue now has a limit of 20 packets and the tcp-turn now has to call send in a single shot to avoid dropping parts of the packet (dropping the length but send the data, or dropping only the padding at the end, etc..)

2 files changed, 34 insertions, 16 deletions

diff --git a/socket/tcp-bsd.c b/socket/tcp-bsd.c
index 2c41d75..2b829ba 100644
--- a/socket/tcp-bsd.c
+++ b/socket/tcp-bsd.c
@@ -70,8 +70,10 @@ typedef struct {
 struct to_be_sent {
   guint length;
   gchar *buf;
+  gboolean can_drop;
 };
 
+#define MAX_QUEUE_LENGTH 20
 
 static void socket_close (NiceSocket *sock);
 static gint socket_recv (NiceSocket *sock, NiceAddress *from,
@@ -222,7 +224,9 @@ socket_recv (NiceSocket *sock, NiceAddress *from, guint len, gchar *buf)
   return ret;
 }
 
-
+/* Data sent to this function must be a single entity because buffers can be
+ * dropped if the bandwidth isn't fast enough. So do not send a message in
+ * multiple chunks. */
 static gboolean
 socket_send (NiceSocket *sock, const NiceAddress *to,
     guint len, const gchar *buf)
@@ -247,10 +251,24 @@ socket_send (NiceSocket *sock, const NiceAddress *to,
         return FALSE;
       }
     } else if ((guint)ret < len) {
-      add_to_be_sent (sock, buf + ret, len - ret, FALSE);
+      add_to_be_sent (sock, buf + ret, len - ret, TRUE);
       return TRUE;
     }
   } else {
+    if (g_queue_get_length(&priv->send_queue) >= MAX_QUEUE_LENGTH) {
+      int peek_idx = 0;
+      struct to_be_sent *tbs = NULL;
+      while ((tbs = g_queue_peek_nth (&priv->send_queue, peek_idx)) != NULL) {
+        if (tbs->can_drop) {
+          tbs = g_queue_pop_nth (&priv->send_queue, peek_idx);
+          g_free (tbs->buf);
+          g_slice_free (struct to_be_sent, tbs);
+          break;
+        } else {
+          peek_idx++;
+        }
+      }
+    }
     add_to_be_sent (sock, buf, len, FALSE);
   }
 
@@ -283,7 +301,7 @@ socket_send_more (
 
   g_static_rec_mutex_lock (&priv->agent->mutex);
 
-  while ((tbs = g_queue_pop_head (&priv->send_queue))) {
+  while ((tbs = g_queue_pop_head (&priv->send_queue)) != NULL) {
     int ret;
 
     ret = send (sock->fileno, tbs->buf, tbs->length, 0);
@@ -338,6 +356,7 @@ add_to_be_sent (NiceSocket *sock, const gchar *buf, guint len, gboolean head)
   tbs = g_slice_new0 (struct to_be_sent);
   tbs->buf = g_memdup (buf, len);
   tbs->length = len;
+  tbs->can_drop = !head;
   if (head)
     g_queue_push_head (&priv->send_queue, tbs);
   else
diff --git a/socket/tcp-turn.c b/socket/tcp-turn.c
index b0306da..0d0dc53 100644
--- a/socket/tcp-turn.c
+++ b/socket/tcp-turn.c
@@ -65,6 +65,7 @@ typedef struct {
   NiceSocket *base_socket;
 } TurnTcpPriv;
 
+#define MAX_UDP_MESSAGE_SIZE 65535
 
 static void socket_close (NiceSocket *sock);
 static gint socket_recv (NiceSocket *sock, NiceAddress *from,
@@ -183,32 +184,30 @@ static gboolean
 socket_send (NiceSocket *sock, const NiceAddress *to,
     guint len, const gchar *buf)
 {
-  gboolean ret = TRUE;
   TurnTcpPriv *priv = sock->priv;
   gchar padbuf[3] = {0, 0, 0};
   int padlen = (len%4) ? 4 - (len%4) : 0;
+  gchar buffer[MAX_UDP_MESSAGE_SIZE + sizeof(guint16) + sizeof(padbuf)];
+  guint buffer_len = 0;
 
   if (priv->compatibility != NICE_TURN_SOCKET_COMPATIBILITY_DRAFT9)
     padlen = 0;
 
   if (priv->compatibility == NICE_TURN_SOCKET_COMPATIBILITY_GOOGLE) {
     guint16 tmpbuf = htons (len);
-    ret = nice_socket_send (priv->base_socket, to,
-        sizeof(guint16), (gchar *)&tmpbuf);
-
-    if (!ret)
-      return ret;
+    memcpy (buffer + buffer_len, (gchar *)&tmpbuf, sizeof(guint16));
+    buffer_len += sizeof(guint16);
   }
 
-  ret = nice_socket_send (priv->base_socket, to, len, buf);
-
-  if (!ret)
-    return ret;
+  memcpy (buffer + buffer_len, buf, len);
+  buffer_len += len;
 
-  if (priv->compatibility == NICE_TURN_SOCKET_COMPATIBILITY_DRAFT9)
-    ret = nice_socket_send (priv->base_socket, to, padlen, padbuf);
+  if (priv->compatibility == NICE_TURN_SOCKET_COMPATIBILITY_DRAFT9) {
+    memcpy (buffer + buffer_len, padbuf, padlen);
+    buffer_len += padlen;
+  }
+  return nice_socket_send (priv->base_socket, to, buffer_len, buffer);
 
-  return ret;
 }