Wireshark · Ethereal-dev: [Ethereal-dev] Patch for packet-bacapp.c

[David Richards <d_m_richards@xxxxxxxxxxx>]

Here is a patch for packet-bacapp.c. 

The changes are:

1) Fix octet string decoding.
2) Create fAccessMethod function to eliminate some redundant code.
3) Make subtree for character string similar to subtree for other types
4) Streamline bitstring subtree creation to eliminate redundant code

--- packet-bacapp.c	2005-08-18 14:55:37.900269300 -0500
+++ y:/devprojects/ethereal/ethereal/epan/dissectors/packet-bacapp.c	2005-08-18 13:28:58.000000000 -0500
@@ -4,7 +4,7 @@
  * Enhanced by Steve Karg, 2005, <skarg@xxxxxxxxxxxxxxxxxxxxx>, Atlanta
  * Enhanced by Herbert Lischka, 2005, <lischka@xxxxxxxxxxxxxxxx>, Berlin
  *
- * $Id$
+ * $Id: packet-bacapp.c 15270 2005-08-10 13:41:13Z sahlberg $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@xxxxxxxxxxxx>
@@ -1911,14 +1911,31 @@
 fOctetString (tvbuff_t *tvb, proto_tree *tree, guint offset, const gchar *label, guint32 lvt)
 {
 	gchar *tmp;
+    guint start = offset;
+    guint8 tag_no, class_tag;
+    guint32 l;
+    proto_tree* subtree = tree;
+    proto_item* ti = 0;
+
+	offset += fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
+
+    while (lvt > 0)
+    {
+        l = min(128,lvt);
+	    tmp = tvb_bytes_to_str(tvb, offset, lvt);
+	    ti = proto_tree_add_text(tree, tvb, offset, lvt, "%s %s", label, tmp);
+        lvt -= l;
+        offset += l;
+    }
 
-	if (lvt == 0)
-		return offset;
+    if (ti != 0)
+    {
+        subtree = proto_item_add_subtree(ti, ett_bacapp_tag);
+    }
 
-	tmp = tvb_bytes_to_str(tvb, offset, lvt);
-	proto_tree_add_text(tree, tvb, offset, lvt, "%s %s", label, tmp);
+    fTagHeaderTree(tvb, subtree, start, &tag_no, &class_tag, &lvt);
 
-	return offset + lvt;
+	return offset;
 }
 
 static guint
@@ -1958,7 +1975,7 @@
 	tag_length = fTagHeader(tvb, offset, &tag_no, &class_tag, &lvt);
 	object_id = tvb_get_ntohl(tvb,offset+tag_length);
 	ti = proto_tree_add_text(tree, tvb, offset, tag_length + 4,
-		"ObjectIdentifier: %s %u",
+		"ObjectIdentifier: %s, %u",
 		val_to_split_str(object_id_type(object_id),
 			128,
 			BACnetObjectType,
@@ -2131,60 +2148,26 @@
 	guint8 tag_no, class_tag, character_set;
 	guint32 lvt, l;
 	size_t inbytesleft, outbytesleft = 512;
-	guint offs;
+	guint offs, extra = 1;
 	guint8 *str_val;
 	guint8 bf_arr[512], *out = &bf_arr[0];
 	proto_item *ti;
 	proto_tree *subtree;
+    guint start = offset;
 
 	if (tvb_length_remaining(tvb, offset) > 0) {
 
 		offs = fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
 	
 		character_set = tvb_get_guint8(tvb, offset+offs);
-		if (character_set == 3) {
-			ti = proto_tree_add_text (tree, tvb, offset, 4+offs,
-				"String Character Set: %s",
-				val_to_str((guint) character_set,
-					BACnetCharacterSet,
-					ASHRAE_Reserved_Fmt));
-			subtree = proto_item_add_subtree(ti, ett_bacapp_tag);
-			fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-			proto_tree_add_item(subtree,
-				hf_BACnetCharacterSet,
-				tvb, offset + offs, 1, FALSE);
-			offset+=4+offs;
-			lvt-=4;
-		}
-		if (character_set == 4) {
-			ti = proto_tree_add_text (tree, tvb, offset, 1+offs,
-				"String Character Set: %s",
-				val_to_str((guint) character_set,
-					BACnetCharacterSet,
-					ASHRAE_Reserved_Fmt));
-			subtree = proto_item_add_subtree(ti, ett_bacapp_tag);
-			fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-			proto_tree_add_item(subtree,
-				hf_BACnetCharacterSet,
-				tvb, offset + offs, 1, FALSE);
-			offset+=1+offs;
-			lvt--;
-		}
-		if ((character_set != 3) && (character_set != 4)) {
-			ti = proto_tree_add_text (tree, tvb, offset, offs+1,
-				"String Character Set: %s",
-				val_to_str(
-					(guint) character_set,
-					BACnetCharacterSet,
-					ASHRAE_Reserved_Fmt));
-			subtree = proto_item_add_subtree(ti, ett_bacapp_tag);
-			fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-			proto_tree_add_item(subtree,
-				hf_BACnetCharacterSet,
-				tvb, offset + offs, 1, FALSE);
-			offset+=1+offs;
-			lvt--;
-		}
+        // Account for code page if DBCS
+        if (character_set == 1)
+        {
+            extra = 3;
+        }
+        offset += (offs+extra);
+        lvt -= (extra);
+
 		do {
 			l = inbytesleft = min(lvt, 255);
 			/*
@@ -2228,10 +2211,19 @@
 				out = str_val;
 				break;
 			}
-			proto_tree_add_text(tree, tvb, offset, l, "%s'%s'", label, out);
+			ti = proto_tree_add_text(tree, tvb, offset, l, "%s'%s'", label, out);
 			lvt-=l;
 			offset+=l;
 		} while (lvt > 0);
+
+		subtree = proto_item_add_subtree(ti, ett_bacapp_tag);
+
+        fTagHeaderTree (tvb, subtree, start, &tag_no, &class_tag, &lvt);
+		proto_tree_add_item(subtree, hf_BACnetCharacterSet, tvb, start+offs, 1, FALSE);
+        if (character_set == 1)
+        {
+            proto_tree_add_text(subtree, tvb, start+offs+1, 2, "Code Page: %d", tvb_get_ntohs(tvb, start+offs+1));
+        }
 	}
 	return offset;
 }
@@ -2241,17 +2233,20 @@
 	const value_string *src)
 {
 	guint8 tag_no, class_tag, tmp;
-	gint j, unused;
+	gint j, unused, skip;
 	guint offs;
-	guint32 lvt, i;
+	guint32 lvt, i, numberOfBytes;
 	guint8 bf_arr[256];
 	
 	offs = fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
+	numberOfBytes = lvt-1; /* Ignore byte for unused bit count */
 	offset+=offs;
 	unused = tvb_get_guint8(tvb, offset); /* get the unused Bits */
-	for (i = 0; i < (lvt-2); i++) {
+	skip = 0;
+	for (i = 0; i < numberOfBytes; i++) {
 		tmp = tvb_get_guint8(tvb, (offset)+i+1);
-		for (j = 0; j < 8; j++) {
+		if (i == numberOfBytes-1) { skip = unused; }
+		for (j = 0; j < 8-skip; j++) {
 			if (src != NULL) {
 				if (tmp & (1 << (7 - j)))
 					proto_tree_add_text(tree, tvb,
@@ -2275,31 +2270,13 @@
 			}
 		}
 	}
-	tmp = tvb_get_guint8(tvb, offset+lvt-1);	/* now the last Byte */
-	if (src == NULL) {
-		for (j = 0; j < (8 - unused); j++)
-			bf_arr[min(255,((lvt-2)*8)+j)] = tmp & (1 << (7 - j)) ? '1' : '0';
-		for (; j < 8; j++)
-			bf_arr[min(255,((lvt-2)*8)+j)] = 'x';
-		bf_arr[min(255,((lvt-2)*8)+j)] = '\0';
+
+	if (src == NULL)
+	{
+		bf_arr[min(255,numberOfBytes*8-unused)] = 0;
 		proto_tree_add_text(tree, tvb, offset, lvt, "%sB'%s'", label, bf_arr);
-	} else {
-		for (j = 0; j < (int) (8 - unused); j++) {
-			if (tmp & (1 << (7 - j)))
-				proto_tree_add_text(tree, tvb, offset+i+1, 1,
-					"%s%s = TRUE",
-					label,
-					val_to_str((guint) (i*8 +j),
-						src,
-						ASHRAE_Reserved_Fmt));
-			else
-				proto_tree_add_text(tree, tvb, offset+i+1, 1,
-					"%s%s = FALSE", label,
-					val_to_str((guint) (i*8 +j),
-						src,
-						ASHRAE_Reserved_Fmt));
-		}
 	}
+
 	offset+=lvt;
 	
 	return offset;
@@ -2320,8 +2297,6 @@
 	guint8 tag_no, class_tag;
 	guint32 lvt;
 	guint tag_len;
-	proto_item *ti;
-	proto_tree *subtree;
 
 	if (tvb_length_remaining(tvb, offset) > 0) {
 
@@ -2347,10 +2322,7 @@
 				offset = fDoubleTag(tvb, tree, offset, label);
 				break;
 			case 6: /** Octet String 20.2.8 */
-				ti = proto_tree_add_text(tree, tvb, offset, lvt+tag_len, "%s (%d Characters)", label, lvt);
-				subtree = proto_item_add_subtree(ti, ett_bacapp_tag);
-				offset += fTagHeaderTree(tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-				offset = fOctetString (tvb, subtree, offset, label, lvt);
+				offset = fOctetString (tvb, tree, offset, label, lvt);
 				break;
 			case 7: /** Character String 20.2.9 */
 				offset = fCharacterString (tvb,tree,offset,label);
@@ -4635,6 +4607,56 @@
 	return offset;
 }
 
+static guint fAccessMethod(tvbuff_t *tvb, proto_tree *tree, guint offset)
+{
+    guint32 lvt;
+    guint8 tag_no, class_tag;
+    proto_item* tt;
+    proto_tree* subtree;
+
+	fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
+
+	switch (tag_no) {
+	case 0:	/* streamAccess */
+		if (lvt_is_opening_tag(lvt) && class_tag) {  
+			tt = proto_tree_add_text(tree, tvb, offset, 1, "stream Access");
+			subtree = proto_item_add_subtree(tt, ett_bacapp_value);
+			offset += fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
+			offset = fApplicationTypes (tvb, subtree, offset, "File Start Position: ");
+			offset = fApplicationTypes (tvb, subtree, offset, "file Data: ");
+		}
+		if (bacapp_flags & 0x04) { /* More Flag is set */
+			break;
+		}
+		fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
+		if (lvt_is_closing_tag(lvt) && class_tag) {
+			offset += fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
+			subtree = tree;
+		}
+		break;
+	case 1:	/* recordAccess */
+		if (lvt_is_opening_tag(lvt) && class_tag) {
+			tt = proto_tree_add_text(tree, tvb, offset, 1, "record Access");
+			subtree = proto_item_add_subtree(tt, ett_bacapp_value);
+			offset += fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
+			offset = fApplicationTypes (tvb, subtree, offset, "File Start Record: ");
+			offset = fApplicationTypes (tvb, subtree, offset, "Record Count: ");
+			offset = fApplicationTypes (tvb, subtree, offset, "Data: ");
+		}
+		if (bacapp_flags & 0x04) { /* More Flag is set */
+			break;
+		}
+		fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
+		if (lvt_is_closing_tag(lvt) && class_tag) {
+			offset += fTagHeaderTree (tvb, subtree, offset,	&tag_no, &class_tag, &lvt);
+			subtree = tree;
+		}
+	break;
+	default:
+		return offset;
+	}
+}
+
 static guint
 fAtomicReadFileRequest(tvbuff_t *tvb, proto_tree *tree, guint offset)
 {
@@ -4694,62 +4716,9 @@
 	proto_tree *subtree = tree;
 	proto_item *tt;
 
-	if ((bacapp_flags & 0x08) && (bacapp_seq != 0)) {	/* Segment of a Request */
-		if (bacapp_flags & 0x04) { /* More Flag is set */
-			/* This is not correct - doesn't do anything since the 0 causes immediate return */
-			offset = fOctetString (tvb, tree, offset, "file Data: ", 0);
-		} else {
-			offset = fOctetString (tvb, tree, offset, "file Data: ", tvb_length_remaining(tvb,offset) - 1);
-			fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
-			if (lvt_is_closing_tag(lvt) && class_tag) { 
-				offset += fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-			}
-		}
-	} else {
-		offset = fObjectIdentifier (tvb, tree, offset); /* file Identifier */
-
-		fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
+	offset = fObjectIdentifier (tvb, tree, offset); /* file Identifier */
+    offset = fAccessMethod(tvb, tree, offset);
 
-		switch (tag_no) {
-		case 0:	/* streamAccess */
-			if (lvt_is_opening_tag(lvt) && class_tag) {  
-				tt = proto_tree_add_text(tree, tvb, offset, 1, "stream Access");
-				subtree = proto_item_add_subtree(tt, ett_bacapp_value);
-				offset += fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-				offset = fApplicationTypes (tvb, subtree, offset, "File Start Position: ");
-				offset = fApplicationTypes (tvb, subtree, offset, "file Data: ");
-			}
-			if (bacapp_flags & 0x04) { /* More Flag is set */
-				break;
-			}
-			fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
-			if (lvt_is_closing_tag(lvt) && class_tag) {
-				offset += fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-				subtree = tree;
-			}
-			break;
-		case 1:	/* recordAccess */
-			if (lvt_is_opening_tag(lvt) && class_tag) {
-				tt = proto_tree_add_text(tree, tvb, offset, 1, "stream Access");
-				subtree = proto_item_add_subtree(tt, ett_bacapp_value);
-				offset += fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-				offset = fApplicationTypes (tvb, subtree, offset, "file Start Record: ");
-				offset = fApplicationTypes (tvb, subtree, offset, "Record Count: ");
-				offset = fApplicationTypes (tvb, subtree, offset, "file Data: ");
-			}
-			if (bacapp_flags & 0x04) { /* More Flag is set */
-				break;
-			}
-			fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
-			if (lvt_is_closing_tag(lvt) && class_tag) {
-				offset += fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-				subtree = tree;
-			}
-			break;
-		default:
-			return offset;
-		}
-	}
 	return offset;
 }
 
@@ -4779,66 +4748,10 @@
 
 	fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
 
-	if ((bacapp_flags & 0x08) && (bacapp_seq != 0)) {	/* Segment of an Request */
-		if (bacapp_flags & 0x04) { /* More Flag is set */
-			/* This is not correct */
-			offset = fOctetString (tvb, tree, offset, "File Data: ", 0);
-		} else {
-			offset = fOctetString (tvb, tree, offset, "File Data: ", tvb_length_remaining(tvb,offset)-1);
-			fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
-			if (lvt_is_closing_tag(lvt) && class_tag) {  
-				offset += fTagHeaderTree (tvb, subtree, offset,
-					&tag_no, &class_tag, &lvt);
-			}
-		}
-	} else {
-		offset = fApplicationTypes (tvb, subtree, offset, "End Of File: ");
-
-		fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
+	offset = fApplicationTypes (tvb, subtree, offset, "End Of File: ");
+    offset = fAccessMethod(tvb, tree, offset);
 
-		switch (tag_no) {
-		case 0:	/* streamAccess */
-			if (lvt_is_opening_tag(lvt) && class_tag) {  
-				tt = proto_tree_add_text(tree, tvb, offset, 1, "stream Access");
-				subtree = proto_item_add_subtree(tt, ett_bacapp_value);
-				offset += fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-				offset = fApplicationTypes (tvb, subtree, offset, "File Start Position: ");
-				offset = fApplicationTypes (tvb, subtree, offset, "file Data: ");
-			}
-			if (bacapp_flags & 0x04) { /* More Flag is set */
-				break;
-			}
-			fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
-			if (lvt_is_closing_tag(lvt) && class_tag) {
-				offset += fTagHeaderTree (tvb, subtree, offset,
-					&tag_no, &class_tag, &lvt);
-				subtree = tree;
-			}
-			break;
-		case 1:	/* recordAccess */
-			if (lvt_is_opening_tag(lvt) && class_tag) {
-				tt = proto_tree_add_text(tree, tvb, offset, 1, "record Access");
-				subtree = proto_item_add_subtree(tt, ett_bacapp_value);
-				offset += fTagHeaderTree (tvb, subtree, offset, &tag_no, &class_tag, &lvt);
-				offset = fApplicationTypes (tvb, subtree, offset, "File Start Record: ");
-				offset = fApplicationTypes (tvb, subtree, offset, "returned Record Count: ");
-				offset = fApplicationTypes (tvb, subtree, offset, "Data: ");
-			}
-			if (bacapp_flags & 0x04) { /* More Flag is set */
-				break;
-			}
-			fTagHeader (tvb, offset, &tag_no, &class_tag, &lvt);
-			if (lvt_is_closing_tag(lvt) && class_tag) {
-				offset += fTagHeaderTree (tvb, subtree, offset,
-					&tag_no, &class_tag, &lvt);
-				subtree = tree;
-			}
-		break;
-		default:
-			return offset;
-		}
-	}
-	return offset;
+    return offset;
 }
 
 static guint