From Tomas Kukosa:

   - display the type of segmented message in the info column
   - don't dissect the last IE in the 1st segment if it is incomplete
   - don't dissect IEs in following segments as segment boundaries
     usually don't IE boundaries

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@10097 f5534014-38df-0310-8fa8-9805f1628bb7

diff --git a/packet-q931.c b/packet-q931.c
index 6a76759159b48786a2dc00baaa54a1132a93a32f..6f71aa645347942ae75a28a46ff51546c75e7953 100644 (file)
--- a/packet-q931.c
+++ b/packet-q931.c
@@ -2,7 +2,7 @@
  * Routines for Q.931 frame disassembly
  * Guy Harris <guy@alum.mit.edu>
  *
- * $Id: packet-q931.c,v 1.68 2004/02/18 09:58:17 guy Exp $
+ * $Id: packet-q931.c,v 1.69 2004/02/18 20:43:37 guy Exp $
  *
  * Modified by Andreas Sikkema for possible use with H.323
  *
@@ -64,6 +64,7 @@ static int hf_q931_call_ref_len                       = -1;
 static int hf_q931_call_ref_flag                       = -1;
 static int hf_q931_call_ref                            = -1;
 static int hf_q931_message_type                        = -1;
+static int hf_q931_segment_type                        = -1;
 static int hf_q931_cause_value                                 = -1;
 static int hf_q931_number_type                         = -1;
 static int hf_q931_numbering_plan                      = -1;
@@ -423,8 +424,7 @@ dissect_q931_segmented_message_ie(tvbuff_t *tvb, int offset, int len,
                    "Not first segment: %u segments remaining",
                    tvb_get_guint8(tvb, offset) & 0x7F);
        }
-       proto_tree_add_text(tree, tvb, offset + 1, 1,
-           "Segmented message type: %u", tvb_get_guint8(tvb, offset + 1));
+       proto_tree_add_item(tree, hf_q931_segment_type, tvb, offset + 1, 1, FALSE);
 }
 
 /*
@@ -2350,11 +2350,12 @@ dissect_q931_IEs(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
        guint8          info_element;
        guint16         info_element_len;
        int             codeset, locked_codeset;
-       gboolean        non_locking_shift;
+       gboolean        non_locking_shift, first_segment;
        tvbuff_t        *h225_tvb, *next_tvb;
 
        codeset = locked_codeset = 0;   /* start out in codeset 0 */
        non_locking_shift = TRUE;
+       first_segment = FALSE;
        while (tvb_reported_length_remaining(tvb, offset) > 0) {
                info_element = tvb_get_guint8(tvb, offset);
 
@@ -2527,6 +2528,11 @@ dissect_q931_IEs(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
                } else {
                        info_element_len = tvb_get_guint8(tvb, offset + 1);
 
+                       if (first_segment && (tvb_reported_length_remaining(tvb, offset + 2) < info_element_len)) {  /* incomplete IE at the end of the 1st segment */
+                               proto_tree_add_text(q931_tree, tvb, offset, tvb_reported_length_remaining(tvb, offset), "Incomplete IE in the 1st segment");
+                               break;
+                       }
+
                        /*
                         * Check for subdissectors for this IE or
                         * for all IEs in this codeset.
@@ -2542,27 +2548,28 @@ dissect_q931_IEs(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
                                }
                        }
 
-                       if (q931_tree != NULL) {
-                               ti = proto_tree_add_text(q931_tree, tvb, offset,
-                                   1+1+info_element_len, "%s",
-                                   val_to_str(info_element, q931_info_element_vals[codeset],
-                                     "Unknown information element (0x%02X)"));
-                                       ie_tree = proto_item_add_subtree(ti, ett_q931_ie);
-                               proto_tree_add_text(ie_tree, tvb, offset, 1,
-                                   "Information element: %s",
-                                   val_to_str(info_element, q931_info_element_vals[codeset],
-                                     "Unknown (0x%02X)"));
-                               proto_tree_add_text(ie_tree, tvb, offset + 1, 1,
-                                   "Length: %u", info_element_len);
-
+                       ti = proto_tree_add_text(q931_tree, tvb, offset, 1+1+info_element_len, "%s",
+                                   val_to_str(info_element, q931_info_element_vals[codeset], "Unknown information element (0x%02X)"));
+                       ie_tree = proto_item_add_subtree(ti, ett_q931_ie);
+                       proto_tree_add_text(ie_tree, tvb, offset, 1, "Information element: %s",
+                                   val_to_str(info_element, q931_info_element_vals[codeset], "Unknown (0x%02X)"));
+                       proto_tree_add_text(ie_tree, tvb, offset + 1, 1, "Length: %u", info_element_len);
+
+                       if (((codeset << 8) | info_element) == (CS0 | Q931_IE_SEGMENTED_MESSAGE)) {
+                               dissect_q931_segmented_message_ie(tvb, offset + 2, info_element_len, ie_tree);
+                               if (check_col(pinfo->cinfo, COL_INFO)) {
+                                       col_append_fstr(pinfo->cinfo, COL_INFO, " of %s",
+                                           val_to_str(tvb_get_guint8(tvb, offset + 3), q931_message_type_vals, "Unknown message type (0x%02X)"));
+                               }
+                               if (tvb_get_guint8(tvb, offset + 2) & 0x80) {  /* the 1st segment */
+                                       first_segment = TRUE;
+                               } else {  /* not the 1st segment */
+                                       proto_tree_add_text(q931_tree, tvb, offset + 4, tvb_reported_length_remaining(tvb, offset + 4), "Message segment");
+                                       info_element_len += tvb_reported_length_remaining(tvb, offset + 4);
+                               }
+                       } else if (q931_tree != NULL) {
                                switch ((codeset << 8) | info_element) {
 
-                               case CS0 | Q931_IE_SEGMENTED_MESSAGE:
-                                       dissect_q931_segmented_message_ie(tvb,
-                                           offset + 2, info_element_len,
-                                           ie_tree);
-                                       break;
-
                                case CS0 | Q931_IE_BEARER_CAPABILITY:
                                case CS0 | Q931_IE_LOW_LAYER_COMPAT:
                                        dissect_q931_bearer_capability_ie(tvb,
@@ -2843,6 +2850,10 @@ proto_register_q931(void)
                  { "Protocol discriminator", "q931.disc", FT_UINT8, BASE_HEX, NULL, 0x0,
                        "", HFILL }},
 
+               { &hf_q931_call_ref_len,
+                 { "Call reference value length", "q931.call_ref_len", FT_UINT8, BASE_DEC, NULL, 0x0,
+                       "", HFILL }},
+
                { &hf_q931_call_ref_flag,
                  { "Call reference flag", "q931.call_ref_flag", FT_BOOLEAN, BASE_NONE, TFS(&tfs_call_ref_flag), 0x0,
                        "", HFILL }},
@@ -2851,6 +2862,13 @@ proto_register_q931(void)
                  { "Call reference value", "q931.call_ref", FT_BYTES, BASE_HEX, NULL, 0x0,
                        "", HFILL }},
 
+               { &hf_q931_message_type,
+                 { "Message type", "q931.message_type", FT_UINT8, BASE_HEX, VALS(q931_message_type_vals), 0x0,
+                       "", HFILL }},
+
+               { &hf_q931_segment_type,
+                 { "Segmented message type", "q931.segment_type", FT_UINT8, BASE_HEX, VALS(q931_message_type_vals), 0x0,
+                       "", HFILL }},
 
                { &hf_q931_coding_standard,
                  { "Coding standard", "q931.coding_standard", FT_UINT8, BASE_HEX,
@@ -2872,14 +2890,6 @@ proto_register_q931(void)
                  { "User information layer 1 protocol", "q931.uil1", FT_UINT8, BASE_HEX,
                         VALS(q931_uil1_vals), 0x1f,"", HFILL }},
 
-               { &hf_q931_call_ref_len,
-                 { "Call reference value length", "q931.call_ref_len", FT_UINT8, BASE_DEC, NULL, 0x0,
-                       "", HFILL }},
-
-               { &hf_q931_message_type,
-                 { "Message type", "q931.message_type", FT_UINT8, BASE_HEX, VALS(q931_message_type_vals), 0x0,
-                       "", HFILL }},
-
                { &hf_q931_cause_value,
                  { "Cause value", "q931.cause_value", FT_UINT8, BASE_DEC, VALS(q931_cause_code_vals), 0x0,
                        "", HFILL }},