ascii value display

Question

how to display character value for a field in my protocol dissection ?i am getting the decimal value ,but want to convert to a character..plz explain

Answer 1

Use FT_STRING field type. Here is an example taken from doc/README.developer:

static hf_register_info hf[] = {
    {&hf_cstring,
     {"C String", "c.string", FT_STRING, BASE_NONE, NULL, 0x0,
      NULL, HFILL}
     }
   };
/**


Dissect a buffer containing ASCII C strings.



@param  tvb     The buffer to dissect.


@param  pinfo   Packet Info.


@param  tree    The protocol tree.
**/
static void dissect_cstr(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
{
guint offset = 0;
while(offset < tvb_reported_length(tvb)) {
gint available = tvb_reported_length_remaining(tvb, offset);
gint len = tvb_strnlen(tvb, offset, available);
if( -1 == len ) {
    /* we ran out of data: ask for more */
    pinfo-&gt;desegment_offset = offset;
    pinfo-&gt;desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
    return;
}

col_set_str(pinfo-&gt;cinfo, COL_INFO, &quot;C String&quot;);

len += 1; /* Add one for the &#39;\0&#39; */

if (tree) {
    proto_tree_add_item(tree, hf_cstring, tvb, offset, len,
        ENC_ASCII|ENC_NA);
}
offset += (guint)len;

}
/* if we get here, then the end of the tvb coincided with the end of a
string. Happy days. */
}

See doc/README.developer or search for FT_STRING usage in the source code for more information.