Add a new "tvb_strsize()" routine, which finds the size of a

NUL-terminated string, starting at a given offset.  The size includes
the terminating NUL.  If it doesn't find the terminating NUL, it throws
the appropriate exception, as either there's no terminating NUL in the
packet or there is but it's past the end of the captured data in the
packet.

Use that routine in the TFTP dissector.  As it throws an exception if
the string isn't NUL-terminated, we can just use "%s" to print option
strings; we don't need to use "%.*s" with a string length.

svn path=/trunk/; revision=2783

1 files changed, 11 insertions, 39 deletions

diff --git a/packet-tftp.c b/packet-tftp.c
index 2c51258b90..8926974bc2 100644
--- a/packet-tftp.c
+++ b/packet-tftp.c
@@ -5,7 +5,7 @@
  * Craig Newell <CraigN@cheque.uq.edu.au>
  *	RFC2347 TFTP Option Extension
  *
- * $Id: packet-tftp.c,v 1.20 2000/12/24 20:33:04 guy Exp $
+ * $Id: packet-tftp.c,v 1.21 2000/12/25 23:48:14 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -87,7 +87,6 @@ static const value_string tftp_error_code_vals[] = {
 };
 
 static void tftp_dissect_options(tvbuff_t *tvb, int offset, proto_tree *tree);
-static gint tftp_strnlen(tvbuff_t *tvb, gint offset);
 
 static void
 dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
@@ -152,12 +151,12 @@ dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	    
 	  switch (opcode) {
 	  case RRQ:
-	    i1 = tftp_strnlen(tvb, offset);
+	    i1 = tvb_strsize(tvb, offset);
 	    proto_tree_add_item(tftp_tree, hf_tftp_source_file,
 			    tvb, offset, i1, FALSE);
 	    offset += i1;
 
-	    i1 = tftp_strnlen(tvb, offset);
+	    i1 = tvb_strsize(tvb, offset);
 	    ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type,
 			    tvb, offset, i1, FALSE);
 	    offset += i1;
@@ -165,12 +164,12 @@ dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	    tftp_dissect_options(tvb, offset, tftp_tree);
 	    break;
 	  case WRQ:
-	    i1 = tftp_strnlen(tvb, offset);
+	    i1 = tvb_strsize(tvb, offset);
 	    proto_tree_add_item(tftp_tree, hf_tftp_destination_file,
 			    tvb, offset, i1, FALSE);
 	    offset += i1;
 
-	    i1 = tftp_strnlen(tvb, offset);
+	    i1 = tvb_strsize(tvb, offset);
 	    ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type,
 			    tvb, offset, i1, FALSE);
 	    offset += i1;
@@ -194,7 +193,7 @@ dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 			    FALSE);
 	    offset += 2;
 
-	    i1 = tftp_strnlen(tvb, offset);
+	    i1 = tvb_strsize(tvb, offset);
 	    proto_tree_add_item(tftp_tree, hf_tftp_error_string, tvb, offset,
 	        i1, FALSE);
 	    break;
@@ -217,44 +216,17 @@ tftp_dissect_options(tvbuff_t *tvb, int offset, proto_tree *tree)
 	int value_offset;
 
 	while (tvb_offset_exists(tvb, offset)) {
-	  option_len = tftp_strnlen(tvb, offset);	/* length of option */
+	  option_len = tvb_strsize(tvb, offset);	/* length of option */
 	  value_offset = offset + option_len;
-	  value_len = tftp_strnlen(tvb, value_offset);	/* length of value */
+	  value_len = tvb_strsize(tvb, value_offset);	/* length of value */
 	  proto_tree_add_text(tree, tvb, offset, option_len+value_len,
-	          "Option: %.*s = %.*s",
-		  option_len - 1, tvb_get_ptr(tvb, offset, option_len - 1),
-		  value_len - 1, tvb_get_ptr(tvb, value_offset, value_len - 1));
+	          "Option: %s = %s",
+		  tvb_get_ptr(tvb, offset, option_len),
+		  tvb_get_ptr(tvb, value_offset, value_len));
 	  offset += option_len + value_len;
 	}
 }
 
-/*
- * Find the length of a null-terminated string in a TFTP packet; if we
- * don't find the '\0', throw an exception, as it means that either
- * we didn't capture enough of the frame, or the frame is malformed.
- *
- * XXX - we'd like to know *which* exception to throw....
- *
- * XXX - this should probably be a standard tvbuff accessor.
- *
- * Add 1 to the resulting length, so that it includes the '\0'.
- */
-static gint
-tftp_strnlen(tvbuff_t *tvb, gint offset)
-{
-	gint len;
-
-	len = tvb_strnlen(tvb, offset, -1);
-	if (len == -1) {
-	    /*
-	     * No '\0' found before the end of the tvbuff; throw an
-	     * exception.
-	     */
-	    THROW(BoundsError);
-	}
-	return len + 1;
-}
-
 void
 proto_register_tftp(void)
 {