Add channel id to UDP framing protocol and allow to dissect only the header of a signalling PDU (as we do for data PDUs)

svn path=/trunk/; revision=50381

epan/dissectors/packet-pdcp-lte.c

@@ -942,6 +942,10 @@ static gboolean dissect_pdcp_lte_heur(tvbuff_t *tvb, packet_info *pinfo,
                 p_pdcp_lte_info->profile = tvb_get_ntohs(tvb, offset);
                 offset += 2;
                 break;
+            case PDCP_LTE_CHANNEL_ID_TAG:
+                p_pdcp_lte_info->channelId = tvb_get_ntohs(tvb, offset);
+                offset += 2;
+                break;
 
             case PDCP_LTE_PAYLOAD_TAG:
                 /* Have reached data, so get out of loop */
@@ -1059,6 +1063,11 @@ static void dissect_pdcp_lte(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree
             write_pdu_label_and_info(root_ti, pinfo, " sn=%-2u ", seqnum);
             offset++;
 
+            if (tvb_length_remaining(tvb, offset) == 0) {
+                /* Only PDCP header was captured, stop dissection here */
+                return;
+            }
+
             /* RRC data is all but last 4 bytes.
                Call lte-rrc dissector (according to direction and channel type) */
             if (global_pdcp_dissect_signalling_plane_as_rrc) {

epan/dissectors/packet-pdcp-lte.h

@@ -161,6 +161,8 @@ typedef struct pdcp_lte_info
 #define PDCP_LTE_ROHC_PROFILE_TAG           0x0C
 /* 2 bytes, network order */
 
+#define PDCP_LTE_CHANNEL_ID_TAG             0x0D
+/* 2 bytes, network order */
 
 /* PDCP PDU. Following this tag comes the actual PDCP PDU (there is no length, the PDU
    continues until the end of the frame) */