[Ronald Henderson <Ronald.Henderson@xxxxxxxxxxxxxxxx>]

Guy:

Etherreal Version: 0.9.7

Did some more investigation on this problem. It appears that on the Windows
platform LDAP entries with Atrribute values (string length) greater than
some number between 220 octects and ITEM_LABEL_LENGTH that the protocol
field will not be displayed. The ability to mouse click or move to the next
attribute value works ok but nothing is displayed (i.e. blank line).
Complete Attribute values that are shorter in length are displayed ok.

I also have a Linux box running 0.9.7 and this problem does not occur. The
Protocol field Attribute values are displayed up to ITEM_LABEL_LENGTH in
size(desired behavior).

I wrote a section of code below to see where the limit on the Windows
platform was. (As I said it is somewhere between ITEM_LABEL_LENGTH and 220
octects). This test was done by introducing an artifical length limit to the
Attribute value in the function read_string_value() in disector: LDAP
(packet-ldap.c)

By truncating the Attribute value to 220 as shown in the example below the
Attribute value fields on the Windows platform now where displayed up to 220
characters.

Any help on where to search next (glib routines?) to solve this issue for
the windows platform would be appreciated.

Also attached is a packet capture file containing a sample LDAP search
request (search for cn=schema) that spans many TCP MTU segments...

Thanks....

I added the code between the RWH bracketed lines...

 

static int read_string_value(ASN1_SCK *a, proto_tree *tree, int hf_id,
	proto_item **new_item, char **s, int start, guint length)
{
  guchar *string;
  proto_item *temp_item = NULL;
  int ret;

  if (length)
  {
    ret = asn1_string_value_decode(a, length, &string);
    if (ret != ASN1_ERR_NOERROR) {
      if (tree) {
        proto_tree_add_text(tree, a->tvb, start, 0,
          "%s: ERROR: Couldn't parse value: %s",
          proto_registrar_get_name(hf_id), asn1_err_to_str(ret));
      }
      return ret;
    }

/* #### RWH code #### */
    if (length >= 220) {
      length = 220;
    }
/* #### RWH code #### */


    string = g_realloc(string, length + 1);
    string[length] = '\0';

  }
  else
    string = "(null)";

  if (tree)
    temp_item = proto_tree_add_string(tree, hf_id, a->tvb, start, a->offset
- start, string);
  if (new_item)
    *new_item = temp_item;

  if (s && length)
    *s = string;
  else if (length)
    g_free(string);

  return ASN1_ERR_NOERROR;
}





-----Original Message-----
From: Guy Harris [mailto:gharris@xxxxxxxxx]
Sent: Friday, November 08, 2002 1:48 AM
To: Oleg Zolotykh
Cc: 'ethereal-users@xxxxxxxxxxxx'; Ronald Henderson
Subject: Re: [Ethereal-users] Problem


On Thu, Nov 07, 2002 at 06:02:02PM -0500, Oleg Zolotykh wrote:
> I have encounter a problem while using Ethereal Network Analyzer. It deals
> with long values of the attributes in LDAP protocol. The values which are
> longer than approximately 150 characters are not displayed.

> I'd like to know if there is a way to change this limitation. It would be
> nice to set a number of characters to be displayed and truncate the others
> for instance.
> Looks like the problem has to do with proto_tree_set_string() function in
> proto.c file.

No, it doesn't, as that function does not impose any length restrictions
on strings.

The truncation is the result of the way the buffer for the
displayable/printable string for a field is allocated; they are
fixed-length buffers, allocated from a GLib "memory chunk", and are
ITEM_LABEL_LENGTH, or 240, bytes long.

See "proto_tree_set_representation()".

The way to change the limitation is to change the value for
ITEM_LABEL_LENGTH in "proto.c" and recompile.

Attachment: ldap2.pkts
Description: Binary data