TryReadFrameHeader, do not assign a value when nothing was read. (Was…

… previously only checked once)
juliusfriedman · Nov 18, 2023 · cf417f4 · cf417f4
1 parent 934e11f
commit cf417f4
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Showing 2 changed files with 15 additions and 13 deletions.
diff --git a/Rtp/RtpClient.Constants.cs b/Rtp/RtpClient.Constants.cs
@@ -101,12 +101,14 @@ internal static void ConfigureRtpThread(System.Threading.Thread thread)//,Common
         /// <param name="readFrameByte">Indicates if the frameByte should be read (RFC2326)</param>
         /// <param name="frameByte">Indicates the frameByte to read</param>
         /// <returns> -1 If the buffer does not contain a RFC2326 / RFC4751 frame at the offset given</returns>
-        internal static int TryReadFrameHeader(byte[] buffer, int offset, out byte channel, byte? frameByte = BigEndianFrameControl, bool readChannel = true)
+        internal static int TryReadFrameHeader(byte[] buffer, int offset, out byte? channel, ref int sessionRequired, byte? frameByte = BigEndianFrameControl, bool readChannel = true)
         {
             //Must be assigned
-            channel = default;
+            channel = null;
 
-            if (Common.Extensions.Array.ArrayExtensions.IsNullOrEmpty(buffer)) return -1;
+            //Ensure enough data is present to read the frame header of the Interlaved Binary Data
+            if (Common.Extensions.Array.ArrayExtensions.IsNullOrEmpty(buffer, out int bufferLength) || 
+                bufferLength - offset < sessionRequired) return -1;
 
             //https://www.ietf.org/rfc/rfc2326.txt
 

diff --git a/Rtp/RtpClient.Methods.cs b/Rtp/RtpClient.Methods.cs
@@ -1196,13 +1196,13 @@ public void DisposeAndClearTransportContexts()
         /// <param name="buffer">The optional buffer to use.</param>
         /// <returns>The amount of bytes the frame data SHOULD have</returns>
         [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]
-        int ReadApplicationLayerFraming(ref int received, ref int sessionRequired, ref int offset, out byte frameChannel, out RtpClient.TransportContext context, out bool raisedEvent, byte[] buffer = null)
+        int ReadApplicationLayerFraming(ref int received, ref int sessionRequired, ref int offset, out byte? frameChannel, out RtpClient.TransportContext context, out bool raisedEvent, byte[] buffer = null)
         {
             //There is no relevant TransportContext assoicated yet.
             context = null;
 
             //The channel of the frame - The Framing Method
-            frameChannel = default(byte);
+            frameChannel = default;
 
             raisedEvent = false;
 
@@ -1257,13 +1257,13 @@ int ReadApplicationLayerFraming(ref int received, ref int sessionRequired, ref i
             //TODO if RFC4571 is specified do check here to avoid reading channel.
 
             //The amount of data needed for the frame comes from TryReadFrameHeader
-            int frameLength = TryReadFrameHeader(buffer, bufferOffset, out frameChannel, BigEndianFrameControl, true);
+            int frameLength = TryReadFrameHeader(buffer, bufferOffset, out frameChannel, ref sessionRequired, BigEndianFrameControl, true);
 
             //Assign a context if there is a frame of any size
-            if (frameLength >= 0)
+            if (frameChannel.HasValue && frameLength >= 0)
             {
                 //Assign the context
-                context = GetContextByChannels(frameChannel);
+                context = GetContextByChannels(frameChannel.Value);
 
                 //Increase the result by the size of the header
                 frameLength += sessionRequired;
@@ -1548,7 +1548,7 @@ int ReadApplicationLayerFraming(ref int received, ref int sessionRequired, ref i
             TransportContext relevent = null;
 
             //The channel of the data
-            byte frameChannel = Common.Binary.Zero;
+            byte? frameChannel = null;
 
             //Get the length of the given buffer (Should actually use m_Buffer.Count when using our own buffer)
             int bufferLength = buffer.Length,
@@ -1681,10 +1681,10 @@ int ReadApplicationLayerFraming(ref int received, ref int sessionRequired, ref i
                                 //If this is a valid context there must be at least a RtpHeader's worth of data in the buffer. 
                                 //If this was a RtcpPacket with only 4 bytes it wouldn't have a ssrc and wouldn't be valid to be sent.
                                 if (incompatible is false &&
-                                    (frameChannel.Equals(relevent.DataChannel) &&
+                                    (frameChannel.HasValue && frameChannel.Equals(relevent.DataChannel) &&
                                     remainingInBuffer < Rtp.RtpHeader.Length + sessionRequired)
                                     ||
-                                    (frameChannel.Equals(relevent.ControlChannel) &&
+                                    (frameChannel.HasValue && frameChannel.Equals(relevent.ControlChannel) &&
                                     remainingInBuffer < Rtcp.RtcpHeader.Length + sessionRequired))
                                 {
                                     //Remove the context
@@ -1707,7 +1707,7 @@ int ReadApplicationLayerFraming(ref int received, ref int sessionRequired, ref i
                                 if (incompatible is false)
                                 {
                                     //Determine if the packet is Rtcp by looking at the found channel and the relvent control channel
-                                    if (frameChannel.Equals(relevent.ControlChannel) && relevent.InDiscovery is false)
+                                    if (frameChannel.HasValue && frameChannel.Equals(relevent.ControlChannel) && relevent.InDiscovery is false)
                                     {
                                         //Rtcp
 
@@ -1795,7 +1795,7 @@ int ReadApplicationLayerFraming(ref int received, ref int sessionRequired, ref i
                         if (jumbo)
                         {
                             //If rtp or rtcp is expected check data
-                            if (expectRtp || expectRtcp || frameChannel < TransportContexts.Count)
+                            if (expectRtp || expectRtcp || frameChannel.HasValue)
                             {
                                 Media.Common.ILoggingExtensions.Log(Logger, InternalId + "ProcessFrameData - Large Packet of " + frameLength + " for Channel " + frameChannel + " remainingInBuffer=" + remainingInBuffer);