Hallo!
After an update from 0.99.6 to 0.99.7 I have problems with a custom dissector
I wrote. On 0.99.6 everything was fine, but now I get the mssage "[Dissector
bug, protocol RTSU: proto.c:1064: failed assertion "length == 6"]". I have no
idea to solve this :( Below is my disscetor-Source. Thank you for your help!
/***Source*******************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/dissectors/packet-tcp.h>
#include <string.h>
#include "units.h"
#define PROTO_TAG_RTSU "RTSU"
#define FRAME_HEADER_LEN 4 // Minumum amount of bytes in PDU to determine
RTSU Packet length
static void dissect_rtsu_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree
*tree);
static void dissect_rtsu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
static guint get_rtsu_message_len(packet_info *pinfo, tvbuff_t *tvb, int
offset);
static guint get_rtsu_pdu_len(packet_info *pinfo, tvbuff_t *tvb, int offset);
static int proto_rtsu = -1;
static dissector_handle_t data_handle=NULL;
static dissector_handle_t rtsu_handle;
void dissect_rtsu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
static int global_rtsu_port = 5555;
static gint hf_rtsu = -1;
static gint hf_rtsu_units = -1;
static gint hf_rtsu_length = -1;
static gint hf_rtsu_ulength = -1;
static gint hf_rtsu_group = -1;
static gint hf_rtsu_unit = -1;
static gint hf_rtsu_data = -1;
static gint ett_rtsu = -1;
static gint ett_rtsu_units = -1;
static gint ett_rtsu_length = -1;
static gint ett_rtsu_ulength = -1;
static gint ett_rtsu_group = -1;
static gint ett_rtsu_unit = -1;
static gint ett_rtsu_data = -1;
void proto_reg_handoff_rtsu(void)
{
static gboolean initialized=FALSE;
if (!initialized) {
data_handle = find_dissector("data");
rtsu_handle = create_dissector_handle(dissect_rtsu, proto_rtsu);
dissector_add("tcp.port", global_rtsu_port, rtsu_handle);
}
}
void proto_register_rtsu (void)
{
/*Register Items: (according to Packet Def. and Unit Def.)
&hf_rtsu: Whole PDU
&hf_rtsu_units: Tree Item 'Units'
&hf_rtsu_length: Packet LEN
&hf_rtsu_ulength: Unit LEN
&hf_rtsu_group: First byte of ID
&hf_rtsu_unit: Second byte if ID
&hf_rtsu_data: Data in Unit
*/
static hf_register_info hf[] = {
{ &hf_rtsu,
{ "Data", "rtsu.data", FT_NONE, BASE_NONE, NULL, 0x0,
"RTSU PDU", HFILL }},
{ &hf_rtsu_units,
{ "Units", "rtsu.units", FT_NONE, BASE_NONE, NULL, 0x0,
"RTSU Units", HFILL }},
{ &hf_rtsu_length,
{ "Packet Length", "rtsu.len", FT_UINT32, BASE_DEC, NULL, 0x0,
"Packet Length", HFILL }},
{ &hf_rtsu_ulength,
{ "Unit Length", "rtsu.ulen", FT_UINT32, BASE_DEC, NULL, 0x0,
"Unit Length", HFILL }},
{ &hf_rtsu_group,
{ "Group", "rtsu.group", FT_UINT8, BASE_DEC,
VALS(packetgroupnames), 0x0,
"Group", HFILL }},
{ &hf_rtsu_unit,
{ "Unit", "rtsu.unit", FT_UINT8, BASE_DEC,
VALS(group20unitnames), 0x0,
"Unit", HFILL }},
{ &hf_rtsu_data,
{ "Data", "rtsu.data", FT_BYTES, BASE_NONE, NULL, 0x0,
"Data", HFILL }}
};
static gint *ett[] = {
&ett_rtsu,
&ett_rtsu_units,
&ett_rtsu_length,
&ett_rtsu_ulength,
&ett_rtsu_group,
&ett_rtsu_unit,
&ett_rtsu_data
};
proto_rtsu = proto_register_protocol ("RTSU Protocol", "RTSU", "rtsu");
proto_register_field_array (proto_rtsu, hf, array_length (hf));
proto_register_subtree_array (ett, array_length (ett));
register_dissector("rtsu", dissect_rtsu, proto_rtsu);
//}
}
//Determine the Unit Length
static guint
get_rtsu_len(packet_info *pinfo, tvbuff_t *tvb, int offset)
{
guint8 l1,l2=0;
guint length=0;
tvb_memcpy(tvb, &l1 , offset+1, 1);
tvb_memcpy(tvb, &l2 , offset, 1);
length=256*l2+l1;
return length;
}
//Determine the Packet Length
static guint
get_rtsu_pdu_len(packet_info *pinfo, tvbuff_t *tvb, int offset)
{
guint8 l1,l2=0;
guint length=0;
tvb_memcpy(tvb, &l1 , offset+3, 1);
tvb_memcpy(tvb, &l2 , offset+2, 1);
length=256*l2+l1+6;
return length;
}
//Dissector Call
static void
dissect_rtsu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
//Reassembling
tcp_dissect_pdus(tvb, pinfo, tree, TRUE, FRAME_HEADER_LEN,
get_rtsu_pdu_len, dissect_rtsu_message);
}
//Main Dissector Function
static void
dissect_rtsu_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *rtsu_item = NULL;
proto_item *rtsu_sub_item = NULL;
proto_tree *rtsu_tree = NULL;
proto_tree *rtsu_units_tree = NULL;
guint16 firstbyte,secondbyte = 0;
guint16 group = 0;
guint16 unit = 0;
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_TAG_RTSU);
if(check_col(pinfo->cinfo,COL_INFO)){
col_clear(pinfo->cinfo,COL_INFO);
}
firstbyte = tvb_get_guint8( tvb, 0 );
secondbyte = tvb_get_guint8( tvb, 1 );
group = tvb_get_guint8( tvb, 6 ); // Get the (first) group byte to
present it
in the Info Col
if (check_col(pinfo->cinfo, COL_INFO)) {
//First and Second Byte should be 0xFA, otherwise it seems not
to be a RTSU
Unit
if ((firstbyte==secondbyte) && (firstbyte == 250)) {
col_add_fstr(pinfo->cinfo, COL_INFO, "%s",
val_to_str(group, packetgroupnames, "Unknown
Group:0x%02x"));
}
else col_add_fstr(pinfo->cinfo, COL_INFO,"no RTSU Unit");
}
//More Information
if (tree) {
guint32 offset = 0; //current postition in PDU
guint32 length=0,ulength = 0;
//The First tree entry is the wohle packet length
rtsu_item = proto_tree_add_item(tree, proto_rtsu, tvb, 0, -1,
FALSE);
rtsu_tree = proto_item_add_subtree(rtsu_item, ett_rtsu);
offset+=2;
length = get_rtsu_len(pinfo, tvb, offset);
proto_tree_add_uint(rtsu_tree, hf_rtsu_length, tvb, offset, 2,
length);
offset+=2;
//The next entry is the sub item 'Units'
rtsu_units_tree = proto_item_add_subtree(rtsu_item, ett_rtsu);
rtsu_sub_item = proto_tree_add_item( rtsu_tree, hf_rtsu_units,
tvb, offset,
length, FALSE );
rtsu_units_tree = proto_item_add_subtree(rtsu_sub_item,
ett_rtsu);
//While there are units left in packet
while (offset<length+4) {
group = tvb_get_guint8( tvb, 6 + offset -4); // Get the
group byte
unit = tvb_get_guint8( tvb, 7 + offset -4); // Get the
unit byte
unit=group*100+unit;// Encode to Unit ID
ulength = get_rtsu_len(pinfo, tvb, offset); //Get the
length of the unit
proto_tree_add_uint(rtsu_units_tree, hf_rtsu_ulength,
tvb, offset, 2,
ulength); //present unit length
offset+=2;
proto_tree_add_item(rtsu_units_tree, hf_rtsu_group,
tvb, offset, 1, FALSE);
//present unit group
offset++;
proto_tree_add_uint(rtsu_units_tree, hf_rtsu_unit, tvb,
offset, 1, unit);
//present unit name
offset++;
proto_tree_add_item( rtsu_units_tree, hf_rtsu_data,
tvb, offset, ulength,
FALSE );//present unit data
offset+=ulength;
}
}
} //End of RTSU dissector function
_______________________________________________
Wireshark-dev mailing list
[email protected]
http://www.wireshark.org/mailman/listinfo/wireshark-dev
