Ported fixes and improvements from Wireshark for RLC/MAC control block decoding. Part 1.

Generic improvements to the csn.1 dissector include:
• Added a flag to the type descriptor structure so that any type can (potentially) flagged as xxx_OR_NULL.  This was specifically needed for UINT_OR_NULL for the ms capabilities struct.
• Changed the CSN_SERIALIZE so that the length of the length field can be specified.
• For CSN_NEXT_EXIST removed the requirement that the next type be CSN_END, to allow truncation of multiple IEs.
• For CSN_LEFT_ALIGNED_VAR_BITMAP corrected the handling of bit_offset.
• Added a new type CSN_PADDING_BITS to make inspection of padding bits more convenient.
• Improved the CSN_RECURSIVE_TARRAY_1 to show the array index.

Improvements to the gsm_rlcmac dissector include:
• Rework the definition of EGPRS Ack/Nack Description so that the length IE (and absence thereof) is handled correctly.
• Added Padding Bits definitions to all PDUs
• Change the Multislot_capability_t and Content_t definitions to allow truncation at any IE

1 files changed, 12 insertions, 3 deletions

diff --git a/src/gsm_rlcmac.h b/src/gsm_rlcmac.h
index afec1468..017b3112 100644
--- a/src/gsm_rlcmac.h
+++ b/src/gsm_rlcmac.h
@@ -454,9 +454,6 @@ typedef struct
 
 typedef struct
 {
-  gboolean Exist_LENGTH;
-  guint8   LENGTH;
-
   guint8   FINAL_ACK_INDICATION;
   guint8   BEGINNING_OF_WINDOW;
   guint8   END_OF_WINDOW;
@@ -469,8 +466,20 @@ typedef struct
 
   guint16  URBB_LENGTH;
   guint8   URBB[URBB_MAX_BITS/8];
+} EGPRS_AckNack_Desc_t;
+
+typedef struct
+{
+  guint8   UnionType;
+  EGPRS_AckNack_Desc_t Desc;
 } EGPRS_AckNack_t;
 
+typedef struct
+{
+  guint8   LENGTH;
+  EGPRS_AckNack_Desc_t Desc;
+} EGPRS_AckNack_w_len_t;
+
 
 /* <P1 Rest Octets>
  * <P2 Rest Octets>