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/* packet-redbackli.c
*
* Redback Lawful Intercept Packet dissector
*
* Copyright 2008 Florian Lohoff <flo[AT]rfc822.org>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald[AT]wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <time.h>
#include <string.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/addr_resolv.h>
#include <epan/prefs.h>
#include <epan/strutil.h>
void proto_reg_handoff_redbackli(void);
static int proto_redbackli = -1;
static int hf_redbackli_seqno = -1; /* Sequence No */
static int hf_redbackli_liid = -1; /* LI Id */
static int hf_redbackli_sessid = -1; /* Session Id */
static int hf_redbackli_label = -1; /* Label */
static int hf_redbackli_eohpad = -1; /* End Of Header Padding */
static int hf_redbackli_unknownavp = -1; /* Unknown AVP */
static int ett_redbackli = -1;
static dissector_handle_t ip_handle;
static dissector_handle_t redbackli_handle;
#define RB_AVP_SEQNO 1
#define RB_AVP_LIID 2
#define RB_AVP_SESSID 3
#define RB_AVP_LABEL 20
#define RB_AVP_EOH 0
static const value_string avp_names[] = {
{RB_AVP_SEQNO, "Sequence No"},
{RB_AVP_LIID, "Lawful Intercept Id"},
{RB_AVP_SESSID, "Session Id"},
{RB_AVP_LABEL, "Label"},
{RB_AVP_EOH, "End Of Header"},
{0, NULL},
};
static int
redbackli_dissect_avp(guint8 avptype, guint8 avplen, tvbuff_t *tvb, gint offset, proto_tree *tree)
{
guint32 avpintval;
char *avpcharval;
const char *avpname;
proto_tree *ti, *st=NULL;
avpname=val_to_str(avptype, avp_names, "Unknown");
if (tree) {
ti = proto_tree_add_text(tree, tvb, offset, avplen+2, "%s AVP", avpname);
st = proto_item_add_subtree(ti, ett_redbackli);
proto_tree_add_text(st, tvb, offset, 1, "AVP Type: %d", avptype);
proto_tree_add_text(st, tvb, offset+1, 1, "AVP Length: %d", avplen);
}
switch(avptype) {
case(RB_AVP_SEQNO):
avpintval=tvb_get_ntohl(tvb, offset+2);
if (tree)
proto_tree_add_uint(st, hf_redbackli_seqno, tvb,
offset+2, avplen, avpintval);
break;
case(RB_AVP_LIID):
avpintval=tvb_get_ntohl(tvb, offset+2);
if (tree)
proto_tree_add_uint(st, hf_redbackli_liid, tvb,
offset+2, avplen, avpintval);
break;
case(RB_AVP_SESSID):
avpintval=tvb_get_ntohl(tvb, offset+2);
if (tree)
proto_tree_add_uint(st, hf_redbackli_sessid, tvb,
offset+2, avplen, avpintval);
break;
case(RB_AVP_LABEL):
avpcharval=tvb_get_string(tvb, offset+2, avplen);
if (tree)
proto_tree_add_string(st, hf_redbackli_label, tvb,
offset+2, avplen, avpcharval);
break;
case(RB_AVP_EOH):
if (tree && avplen)
proto_tree_add_item(st, hf_redbackli_eohpad, tvb,
offset+2, avplen, FALSE);
return 1;
default:
if (tree && avplen)
proto_tree_add_item(st, hf_redbackli_unknownavp, tvb,
offset+2, avplen, FALSE);
return 0;
}
return 0;
}
static void
redbackli_dissect(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
guint8 avptype, avplen;
gint len, offset=0, eoh=0;
proto_tree *ti, *redbackli_tree=NULL;
tvbuff_t *next_tvb;
if(check_col(pinfo->cinfo,COL_PROTOCOL))
col_add_str(pinfo->cinfo,COL_PROTOCOL,"RBLI");
if (tree) {
ti = proto_tree_add_item(tree, proto_redbackli,
tvb, 0, -1, FALSE);
redbackli_tree = proto_item_add_subtree(ti, ett_redbackli);
}
len=tvb_length(tvb);
offset=0;
eoh=0;
while(!eoh && len > 2) {
avptype = tvb_get_guint8(tvb, offset+0);
avplen = tvb_get_guint8(tvb, offset+1);
if (len < avplen+2) /* AVP Complete ? */
break;
eoh=redbackli_dissect_avp(avptype, avplen, tvb, offset, redbackli_tree);
offset+=2+avplen;
len-=2+avplen;
}
next_tvb = tvb_new_subset(tvb, offset, -1, -1);
call_dissector(ip_handle, next_tvb, pinfo, tree);
}
#define REDBACKLI_INTSIZE 6
#define REDBACKLI_EOHSIZE 2
#define MIN_REDBACKLI_SIZE (3*REDBACKLI_INTSIZE+REDBACKLI_EOHSIZE)
static gboolean
redbackli_dissect_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
gint len, offset=0, eoh=0;
guint8 avptype, avplen;
len=tvb_length(tvb);
if (len < MIN_REDBACKLI_SIZE)
return FALSE;
/*
* We scan the possible AVPs and look out for mismatches.
* An int AVP needs to be 4 byte long, and the eoh must be 0 or 1
* long .. Unknown AVPs also mean not for us ...
*
*/
while(len > 2 && !eoh) {
avptype = tvb_get_guint8(tvb, offset+0);
avplen = tvb_get_guint8(tvb, offset+1);
switch(avptype) {
case(RB_AVP_SEQNO):
case(RB_AVP_LIID):
case(RB_AVP_SESSID):
if (avplen != 4)
return FALSE;
break;
case(RB_AVP_LABEL):
break;
case(RB_AVP_EOH):
if (avplen > 1)
return FALSE;
eoh=1;
break;
default:
return FALSE;
}
offset+=2+avplen;
len-=2+avplen;
}
redbackli_dissect(tvb, pinfo, tree);
return TRUE;
}
void proto_register_redbackli(void) {
static hf_register_info hf[] = {
{ &hf_redbackli_seqno,
{ "Sequence No", "redbackli.seqno", FT_UINT32, BASE_DEC, NULL, 0x0,
"Sequence No", HFILL }},
{ &hf_redbackli_liid,
{ "Lawful Intercept Id", "redbackli.liid", FT_UINT32, BASE_DEC, NULL, 0x0,
"LI Identifier", HFILL }},
{ &hf_redbackli_sessid,
{ "Session Id", "redbackli.sessid", FT_UINT32, BASE_DEC, NULL, 0x0,
"Session Identifier", HFILL }},
{ &hf_redbackli_label,
{ "Label", "redbackli.label", FT_STRING, BASE_NONE, NULL, 0x0,
"Label", HFILL }},
{ &hf_redbackli_eohpad,
{ "End of Header Padding", "redbackli.eohpad", FT_BYTES, BASE_HEX, NULL, 0x0,
"", HFILL }},
{ &hf_redbackli_unknownavp,
{ "Unknown AVP", "redbackli.unknownavp", FT_BYTES, BASE_HEX, NULL, 0x0,
"", HFILL }},
};
static gint *ett[] = {
&ett_redbackli,
};
proto_redbackli = proto_register_protocol("Redback Lawful Intercept",
"RedbackLI","redbackli");
proto_register_field_array(proto_redbackli,hf,array_length(hf));
proto_register_subtree_array(ett,array_length(ett));
register_dissector("redbackli", redbackli_dissect, proto_redbackli);
}
void proto_reg_handoff_redbackli(void) {
ip_handle = find_dissector("ip");
redbackli_handle = find_dissector("redbackli");
dissector_add_handle("udp.port", redbackli_handle);
heur_dissector_add("udp", redbackli_dissect_heur, proto_redbackli);
}
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