rtcpbuffer: Update package validation to support reduced size rtcp packets

According to this section of the rfc.
https://tools.ietf.org/html/rfc5506#section-3.4.2
The validation should be updated to accept more types of RTCP
packages, with this mask change feedback packages will be also
accepted.

Change-Id: If5ead59e03c7c60bbe45a9b09f3ff680e7fa4868

gst-libs/gst/rtp/gstrtcpbuffer.c

@@ -87,20 +87,9 @@ gst_rtcp_buffer_new_copy_data (gpointer data, guint len)
   return gst_rtcp_buffer_new_take_data (g_memdup (data, len), len);
 }
 
-/**
- * gst_rtcp_buffer_validate_data:
- * @data: (array length=len): the data to validate
- * @len: the length of @data to validate
- *
- * Check if the @data and @size point to the data of a valid RTCP (compound)
- * packet. 
- * Use this function to validate a packet before using the other functions in
- * this module.
- *
- * Returns: TRUE if the data points to a valid RTCP packet.
- */
-gboolean
-gst_rtcp_buffer_validate_data (guint8 * data, guint len)
+static gboolean
+gst_rtcp_buffer_validate_data_internal (guint8 * data, guint len,
+    guint16 valid_mask)
 {
   guint16 header_mask;
   guint header_len;
@@ -116,7 +105,7 @@ gst_rtcp_buffer_validate_data (guint8 * data, guint len)
     goto wrong_length;
 
   /* first packet must be RR or SR  and version must be 2 */
-  header_mask = ((data[0] << 8) | data[1]) & GST_RTCP_VALID_MASK;
+  header_mask = ((data[0] << 8) | data[1]) & valid_mask;
   if (G_UNLIKELY (header_mask != GST_RTCP_VALID_VALUE))
     goto wrong_mask;
 
@@ -169,8 +158,7 @@ wrong_length:
   }
 wrong_mask:
   {
-    GST_DEBUG ("mask check failed (%04x != %04x)", header_mask,
-        GST_RTCP_VALID_VALUE);
+    GST_DEBUG ("mask check failed (%04x != %04x)", header_mask, valid_mask);
     return FALSE;
   }
 wrong_version:
@@ -185,6 +173,72 @@ wrong_padding:
   }
 }
 
+/**
+ * gst_rtcp_buffer_validate_data_reduced:
+ * @data: (array length=len): the data to validate
+ * @len: the length of @data to validate
+ *
+ * Check if the @data and @size point to the data of a valid RTCP
+ * packet.
+ * Use this function to validate a packet before using the other functions in
+ * this module.
+ *
+ * This function is updated to support reduced size rtcp packets according to
+ * RFC 5506
+ *
+ * Returns: TRUE if the data points to a valid RTCP packet.
+ */
+gboolean
+gst_rtcp_buffer_validate_data_reduced (guint8 * data, guint len)
+{
+  return gst_rtcp_buffer_validate_data_internal (data, len,
+      GST_RTCP_REDUCED_SIZE_VALID_MASK);
+}
+
+/**
+ * gst_rtcp_buffer_validate_data:
+ * @data: (array length=len): the data to validate
+ * @len: the length of @data to validate
+ *
+ * Check if the @data and @size point to the data of a valid RTCP (compound)
+ * packet.
+ * Use this function to validate a packet before using the other functions in
+ * this module.
+ *
+ *
+ * Returns: TRUE if the data points to a valid RTCP packet.
+ */
+gboolean
+gst_rtcp_buffer_validate_data (guint8 * data, guint len)
+{
+  return gst_rtcp_buffer_validate_data_internal (data, len,
+      GST_RTCP_VALID_MASK);
+}
+
+/**
+ * gst_rtcp_buffer_validate_reduced:
+ * @buffer: the buffer to validate
+ *
+ * Check if the data pointed to by @buffer is a valid RTCP packet using
+ * gst_rtcp_buffer_validate_reduced().
+ *
+ * Returns: TRUE if @buffer is a valid RTCP packet.
+ */
+gboolean
+gst_rtcp_buffer_validate_reduced (GstBuffer * buffer)
+{
+  gboolean res;
+  GstMapInfo map;
+
+  g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
+
+  gst_buffer_map (buffer, &map, GST_MAP_READ);
+  res = gst_rtcp_buffer_validate_data_reduced (map.data, map.size);
+  gst_buffer_unmap (buffer, &map);
+
+  return res;
+}
+
 /**
  * gst_rtcp_buffer_validate:
  * @buffer: the buffer to validate

gst-libs/gst/rtp/gstrtcpbuffer.h

@@ -168,6 +168,15 @@ typedef enum
  * Mask for version, padding bit and packet type pair
  */
 #define GST_RTCP_VALID_MASK (0xc000 | 0x2000 | 0xfe)
+
+/**
+ * GST_RTCP_REDUCED_SIZE_VALID_MASK:
+ *
+ * Mask for version, padding bit and packet type pair allowing reduced size
+ * packets, basically it accepts other types than RR and SR
+ */
+#define GST_RTCP_REDUCED_SIZE_VALID_MASK (0xc000 | 0x2000 | 0xf8)
+
 /**
  * GST_RTCP_VALID_VALUE:
  *
@@ -218,6 +227,10 @@ GstBuffer*      gst_rtcp_buffer_new_copy_data     (gpointer data, guint len);
 gboolean        gst_rtcp_buffer_validate_data     (guint8 *data, guint len);
 gboolean        gst_rtcp_buffer_validate          (GstBuffer *buffer);
 
+gboolean        gst_rtcp_buffer_validate_data_reduced   (guint8 *data, guint len);
+gboolean        gst_rtcp_buffer_validate_reduced        (GstBuffer *buffer);
+
+
 GstBuffer*      gst_rtcp_buffer_new               (guint mtu);
 
 gboolean        gst_rtcp_buffer_map               (GstBuffer *buffer, GstMapFlags flags, GstRTCPBuffer *rtcp);

tests/check/libs/rtp.c

@@ -757,6 +757,40 @@ GST_START_TEST (test_rtcp_buffer)
   /* close and validate */
   gst_rtcp_buffer_unmap (&rtcp);
   fail_unless (gst_rtcp_buffer_validate (buf) == TRUE);
+  fail_unless (gst_rtcp_buffer_validate_reduced (buf) == TRUE);
+  gst_buffer_unref (buf);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_rtcp_reduced_buffer)
+{
+  GstBuffer *buf;
+  GstRTCPPacket packet;
+  GstRTCPBuffer rtcp = { NULL, };
+  gsize offset;
+  gsize maxsize;
+
+  buf = gst_rtcp_buffer_new (1400);
+  fail_unless (buf != NULL);
+  fail_unless_equals_int (gst_buffer_get_sizes (buf, &offset, &maxsize), 0);
+  fail_unless_equals_int (offset, 0);
+  fail_unless_equals_int (maxsize, 1400);
+
+  gst_rtcp_buffer_map (buf, GST_MAP_READWRITE, &rtcp);
+
+  fail_unless (gst_rtcp_buffer_validate (buf) == FALSE);
+  fail_unless (gst_rtcp_buffer_get_first_packet (&rtcp, &packet) == FALSE);
+  fail_unless (gst_rtcp_buffer_get_packet_count (&rtcp) == 0);
+
+  /* add an SR packet */
+  fail_unless (gst_rtcp_buffer_add_packet (&rtcp, GST_RTCP_TYPE_PSFB,
+          &packet) == TRUE);
+
+  /* close and validate */
+  gst_rtcp_buffer_unmap (&rtcp);
+  fail_unless (gst_rtcp_buffer_validate (buf) == FALSE);
+  fail_unless (gst_rtcp_buffer_validate_reduced (buf) == TRUE);
   gst_buffer_unref (buf);
 }
 
@@ -992,6 +1026,7 @@ rtp_suite (void)
   tcase_add_test (tc_chain, test_rtp_seqnum_compare);
 
   tcase_add_test (tc_chain, test_rtcp_buffer);
+  tcase_add_test (tc_chain, test_rtcp_reduced_buffer);
   tcase_add_test (tc_chain, test_rtp_ntp64_extension);
   tcase_add_test (tc_chain, test_rtp_ntp56_extension);