Add proto_tree_add_checksum.

This is an attempt to standardize display/handling of checksum fields for all dissectors.
The main target is for dissectors that do validation, but dissectors that just report the
checksum were also included just to make them easier to find in the future.

Bug: 10620
Bug: 12058
Ping-Bug: 8859
Change-Id: Ia8abd86e42eaf8ed50de6b173409e914b17993bf
Reviewed-on: https://code.wireshark.org/review/16380
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Jeff Morriss <jeff.morriss.ws@gmail.com>
Reviewed-by: Michael Mann <mmann78@netscape.net>

1 files changed, 17 insertions, 31 deletions

diff --git a/epan/dissectors/packet-sml.c b/epan/dissectors/packet-sml.c
index 7d405519c7..6f4916e24f 100644
--- a/epan/dissectors/packet-sml.c
+++ b/epan/dissectors/packet-sml.c
@@ -93,6 +93,7 @@ static int hf_sml_datatype = -1;
 static int hf_sml_abortOnError = -1;
 static int hf_sml_MessageBody = -1;
 static int hf_sml_crc16 = -1;
+static int hf_sml_crc16_status = -1;
 static int hf_sml_endOfSmlMsg = -1;
 static int hf_sml_end = -1;
 static int hf_sml_codepage = -1;
@@ -2391,31 +2392,22 @@ static void dissect_sml_file(tvbuff_t *tvb, packet_info *pinfo, gint *offset, pr
 			proto_tree_add_item (crc16_tree, hf_sml_datatype, tvb, *offset, 1, ENC_BIG_ENDIAN);
 			*offset+=1;
 
-			crc16 = proto_tree_add_item (crc16_tree, hf_sml_crc16, tvb, *offset, data, ENC_BIG_ENDIAN);
-			*offset+=data;
-
 			if (sml_crc_enabled) {
-				crc_msg_len = (*offset - crc_msg_len - data - 1);
-				crc_check = crc16_ccitt_tvb_offset(tvb, (*offset - crc_msg_len - data - 1), crc_msg_len);
-				crc_ref = tvb_get_letohs(tvb, *offset-2);
+				crc_msg_len = (*offset - crc_msg_len - 1);
+				crc_check = crc16_ccitt_tvb_offset(tvb, (*offset - crc_msg_len - 1), crc_msg_len);
 
 				if (data == 1){
 					crc_ref = crc_ref & 0xFF00;
 				}
 
-				if (crc_check == crc_ref) {
-					proto_item_append_text(crc16, " [CRC Okay]");
-				}
-				else {
-					/*(little to big endian convert) to display in correct order*/
-					crc_check = ((crc_check >> 8) & 0xFF) + ((crc_check << 8 & 0xFF00));
-					proto_item_append_text(crc16, " [CRC Bad 0x%X]", crc_check);
-					expert_add_info(pinfo, crc16, &ei_sml_crc_error);
-				}
+				proto_tree_add_checksum(crc16_tree, tvb, *offset, hf_sml_crc16, hf_sml_crc16_status, &ei_sml_crc_error, pinfo, crc_check,
+									ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
 			}
 			else {
-				proto_item_append_text(crc16, " [CRC validation disabled]");
+				proto_tree_add_checksum(crc16_tree, tvb, *offset, hf_sml_crc16, hf_sml_crc16_status, &ei_sml_crc_error, pinfo, 0,
+									ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
 			}
+			*offset+=data;
 
 			/*Message END*/
 			if (tvb_get_guint8 (tvb, *offset) == 0){
@@ -2477,27 +2469,19 @@ static void dissect_sml_file(tvbuff_t *tvb, packet_info *pinfo, gint *offset, pr
 		*offset+=1;
 		proto_tree_add_item (msgend_tree, hf_sml_padding, tvb, *offset, 1, ENC_NA);
 		*offset+=1;
-		crc16 = proto_tree_add_item (msgend_tree, hf_sml_crc16, tvb, *offset, 2, ENC_BIG_ENDIAN);
-		*offset+=2;
 
 		if (sml_crc_enabled && sml_reassemble){
-			crc_file_len = *offset - crc_file_len - 2;
-			crc_check = crc16_ccitt_tvb_offset(tvb,*offset-crc_file_len-2, crc_file_len);
-			crc_ref = tvb_get_letohs(tvb, *offset-2);
+			crc_file_len = *offset - crc_file_len;
+			crc_check = crc16_ccitt_tvb_offset(tvb,*offset-crc_file_len, crc_file_len);
 
-			if (crc_check == crc_ref){
-				proto_item_append_text(crc16, " [CRC Okay]");
-			}
-			else{
-				/*(little to big endian convert) to display in correct order*/
-				crc_check = ((crc_check >> 8) & 0xFF) + ((crc_check << 8) & 0xFF00);
-				proto_item_append_text(crc16, " [CRC Bad 0x%X]", crc_check);
-				expert_add_info_format(pinfo, msgend, &ei_sml_crc_error, "CRC error (messages not reassembled ?)");
-			}
+			proto_tree_add_checksum(msgend_tree, tvb, *offset, hf_sml_crc16, hf_sml_crc16_status, &ei_sml_crc_error, pinfo, crc_check,
+									ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
 		}
 		else {
-			proto_item_append_text(crc16, " [CRC validation disabled]");
+			proto_tree_add_checksum(msgend_tree, tvb, *offset, hf_sml_crc16, hf_sml_crc16_status, &ei_sml_crc_error, pinfo, crc_check,
+									ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
 		}
+		*offset+=2;
 
 		available = tvb_reported_length_remaining(tvb, *offset);
 		if (available <= 0){
@@ -2556,6 +2540,8 @@ void proto_register_sml (void) {
 			{ "SML Version", "sml.version", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }},
 		{ &hf_sml_crc16,
 			{ "CRC16", "sml.crc", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL }},
+		{ &hf_sml_crc16_status,
+			{ "CRC16 Status", "sml.crc.status", FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0, NULL, HFILL }},
 		{ &hf_sml_endOfSmlMsg,
 			{ "End of SML Msg", "sml.end", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }},
 		{ &hf_sml_transactionId,