Wireshark · Ethereal-dev: [Ethereal-dev] Patch for q931

[Tomas Kukosa <tomas.kukosa@xxxxxxxxxxx>]

The attached patch contains following changes:
  - type of segmented message is displayed in the info column
  - the last IE in the 1st segment is not dissected if it is incomplete
  - IEs in following segments are not dissected as segment boundaries usually does not match IE boundaries

Regards,
  Tomas

*** Ethereal\packet-q931.c	Wed Feb 18 08:21:55 2004
--- Ethereal_new\packet-q931.c	Wed Feb 18 11:00:13 2004
***************
*** 64,69 ****
--- 64,70 ----
  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;
***************
*** 423,430 ****
  		    "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\n", tvb_get_guint8(tvb, offset + 1));
  }
  
  /*
--- 424,430 ----
  		    "Not first segment: %u segments remaining",
  		    tvb_get_guint8(tvb, offset) & 0x7F);
  	}
! 	proto_tree_add_item(tree, hf_q931_segment_type, tvb, offset + 1, 1, FALSE);
  }
  
  /*
***************
*** 2345,2355 ****
  	guint8		info_element;
  	guint16		info_element_len;
  	int		codeset, locked_codeset;
! 	gboolean	non_locking_shift;
  	tvbuff_t	*h225_tvb, *next_tvb;
  
  	codeset = locked_codeset = 0;	/* start out in codeset 0 */
  	non_locking_shift = TRUE;
  	while (tvb_reported_length_remaining(tvb, offset) > 0) {
  		info_element = tvb_get_guint8(tvb, offset);
  
--- 2345,2356 ----
  	guint8		info_element;
  	guint16		info_element_len;
  	int		codeset, locked_codeset;
! 	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);
  
***************
*** 2522,2527 ****
--- 2523,2533 ----
  		} 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.
***************
*** 2537,2563 ****
  				}
  			}
  
! 			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);
! 
  				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,
--- 2543,2570 ----
  				}
  			}
  
! 			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_BEARER_CAPABILITY:
  				case CS0 | Q931_IE_LOW_LAYER_COMPAT:
  					dissect_q931_bearer_capability_ie(tvb,
***************
*** 2838,2843 ****
--- 2845,2854 ----
  		  { "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 }},
***************
*** 2846,2851 ****
--- 2857,2869 ----
  		  { "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,
***************
*** 2867,2880 ****
  		  { "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 }},
--- 2885,2890 ----