290 lines
8.0 KiB
C
290 lines
8.0 KiB
C
/* packet-redbackli.c
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*
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* $Id$
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*
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* Redback Lawful Intercept Packet dissector
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*
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* Copyright 2008 Florian Lohoff <flo[AT]rfc822.org>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald[AT]wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/addr_resolv.h>
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#include <epan/strutil.h>
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static int proto_redbackli = -1;
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static int hf_redbackli_seqno = -1; /* Sequence No */
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static int hf_redbackli_liid = -1; /* LI Id */
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static int hf_redbackli_sessid = -1; /* Session Id */
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static int hf_redbackli_label = -1; /* Label */
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static int hf_redbackli_acctid = -1; /* Accounting Session Id */
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static int hf_redbackli_dir = -1; /* Direction */
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static int hf_redbackli_eohpad = -1; /* End Of Header Padding */
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static int hf_redbackli_unknownavp = -1; /* Unknown AVP */
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static int ett_redbackli = -1;
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static dissector_handle_t ip_handle;
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#define RB_AVP_SEQNO 1
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#define RB_AVP_LIID 2
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#define RB_AVP_SESSID 3
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#define RB_AVP_DIR 4
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#define RB_AVP_LABEL 20
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#define RB_AVP_ACCTID 40
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#define RB_AVP_EOH 0
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static const value_string avp_names[] = {
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{RB_AVP_SEQNO, "Sequence No"},
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{RB_AVP_LIID, "Lawful Intercept Id"},
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{RB_AVP_SESSID, "Session Id"},
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{RB_AVP_LABEL, "Label"},
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{RB_AVP_ACCTID, "Accounting Session Id"},
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{RB_AVP_DIR, "Direction"},
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{RB_AVP_EOH, "End Of Header"},
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{0, NULL}
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};
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static void
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redbackli_dissect_avp(guint8 avptype, guint8 avplen, tvbuff_t *tvb, gint offset, proto_tree *tree)
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{
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const char *avpname;
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proto_tree *ti, *st=NULL;
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avpname=val_to_str_const(avptype, avp_names, "Unknown");
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ti = proto_tree_add_text(tree, tvb, offset, avplen+2, "%s AVP", avpname);
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st = proto_item_add_subtree(ti, ett_redbackli);
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proto_tree_add_text(st, tvb, offset, 1, "AVP Type: %d", avptype);
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proto_tree_add_text(st, tvb, offset+1, 1, "AVP Length: %d", avplen);
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if (!avplen)
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return;
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/* XXX: ToDo: Validate the length (avplen) of the fixed length fields
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before calling proto_tree_add_item().
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Note that the field lengths have been validated when
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dissect_avp() is called from redbackli_dissect_heur().
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*/
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switch(avptype) {
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case(RB_AVP_SEQNO):
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proto_tree_add_item(st, hf_redbackli_seqno, tvb,
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offset+2, avplen, ENC_BIG_ENDIAN);
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break;
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case(RB_AVP_LIID):
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proto_tree_add_item(st, hf_redbackli_liid, tvb,
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offset+2, avplen, ENC_BIG_ENDIAN);
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break;
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case(RB_AVP_SESSID):
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proto_tree_add_item(st, hf_redbackli_sessid, tvb,
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offset+2, avplen, ENC_BIG_ENDIAN);
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break;
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case(RB_AVP_LABEL):
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proto_tree_add_item(st, hf_redbackli_label, tvb,
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offset+2, avplen, ENC_ASCII|ENC_NA);
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break;
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case(RB_AVP_EOH):
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proto_tree_add_item(st, hf_redbackli_eohpad, tvb,
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offset+2, avplen, ENC_NA);
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break;
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case(RB_AVP_DIR):
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proto_tree_add_item(st, hf_redbackli_dir, tvb,
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offset+2, avplen, ENC_NA);
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break;
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case(RB_AVP_ACCTID):
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proto_tree_add_item(st, hf_redbackli_acctid, tvb,
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offset+2, avplen, ENC_NA);
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break;
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default:
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proto_tree_add_item(st, hf_redbackli_unknownavp, tvb,
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offset+2, avplen, ENC_NA);
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break;
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}
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return;
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}
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static void
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redbackli_dissect(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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guint8 avptype, avplen;
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gint len, offset=0;
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gboolean eoh;
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proto_tree *ti, *redbackli_tree=NULL;
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tvbuff_t *next_tvb;
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col_set_str(pinfo->cinfo,COL_PROTOCOL,"RBLI");
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if (tree) {
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ti = proto_tree_add_item(tree, proto_redbackli,
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tvb, 0, -1, ENC_NA);
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redbackli_tree = proto_item_add_subtree(ti, ett_redbackli);
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}
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len=tvb_length(tvb);
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offset=0;
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eoh=FALSE;
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while(!eoh && (len > 2)) {
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avptype = tvb_get_guint8(tvb, offset+0);
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avplen = tvb_get_guint8(tvb, offset+1);
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if ((len-2) < avplen) /* AVP Complete ? */
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break;
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if (tree)
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redbackli_dissect_avp(avptype, avplen, tvb, offset, redbackli_tree);
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if (avptype == RB_AVP_EOH)
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eoh=TRUE;
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offset+=2+avplen;
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len-=2+avplen;
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}
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next_tvb = tvb_new_subset_remaining(tvb, offset);
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call_dissector(ip_handle, next_tvb, pinfo, tree);
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}
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#define REDBACKLI_INTSIZE 6
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#define REDBACKLI_EOHSIZE 2
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#define MIN_REDBACKLI_SIZE (3*REDBACKLI_INTSIZE+REDBACKLI_EOHSIZE)
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static gboolean
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redbackli_dissect_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
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{
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gint len, offset=0;
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gboolean eoh=FALSE;
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guint8 avptype, avplen;
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guint32 avpfound=0;
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len=tvb_length(tvb);
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if (len < MIN_REDBACKLI_SIZE)
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return FALSE;
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/*
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* We scan the possible AVPs and look out for mismatches.
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* An int AVP needs to be 4 byte long, and the eoh must be 0 or 1
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* long .. Unknown AVPs also mean not for us ...
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*
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*/
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while((len > 2) && !eoh) {
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avptype = tvb_get_guint8(tvb, offset+0);
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avplen = tvb_get_guint8(tvb, offset+1);
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switch(avptype) {
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case(RB_AVP_SEQNO):
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case(RB_AVP_LIID):
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case(RB_AVP_SESSID):
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if (avplen != 4)
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return FALSE;
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avpfound|=1<<avptype;
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break;
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case(RB_AVP_EOH):
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if (avplen > 1 || offset == 0)
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return FALSE;
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eoh=TRUE;
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break;
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case(RB_AVP_LABEL):
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case(RB_AVP_DIR): /* Is this correct? the hf_ originally had FT_UINT8 for DIR */
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case(RB_AVP_ACCTID):
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break;
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default:
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return FALSE;
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}
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offset+=2+avplen;
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len-=2+avplen;
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}
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if (!(avpfound & (1<<RB_AVP_SEQNO)))
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return FALSE;
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if (!(avpfound & (1<<RB_AVP_SESSID)))
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return FALSE;
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if (!(avpfound & (1<<RB_AVP_LIID)))
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return FALSE;
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redbackli_dissect(tvb, pinfo, tree);
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return TRUE;
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}
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void proto_register_redbackli(void) {
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static hf_register_info hf[] = {
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{ &hf_redbackli_seqno,
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{ "Sequence No", "redbackli.seqno", FT_UINT32, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_redbackli_liid,
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{ "Lawful Intercept Id", "redbackli.liid", FT_UINT32, BASE_DEC, NULL, 0x0,
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"LI Identifier", HFILL }},
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{ &hf_redbackli_sessid,
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{ "Session Id", "redbackli.sessid", FT_UINT32, BASE_DEC, NULL, 0x0,
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"Session Identifier", HFILL }},
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{ &hf_redbackli_dir,
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#if 0 /* XXX: If one goes by the heuristic then this field can be variable length ??
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In the absence of any documentation We'll assume that's the case
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(even though 'direction' sounds like a fixed length field */
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{ "Direction", "redbackli.dir", FT_UINT8, BASE_DEC, NULL, 0x0,
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#endif
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{ "Direction", "redbackli.dir", FT_BYTES, BASE_NONE, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_redbackli_label,
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{ "Label", "redbackli.label", FT_STRING, BASE_NONE, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_redbackli_acctid,
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{ "Acctid", "redbackli.acctid", FT_BYTES, BASE_NONE, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_redbackli_eohpad,
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{ "End of Header Padding", "redbackli.eohpad", FT_BYTES, BASE_NONE, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_redbackli_unknownavp,
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{ "Unknown AVP", "redbackli.unknownavp", FT_BYTES, BASE_NONE, NULL, 0x0,
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NULL, HFILL }}
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};
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static gint *ett[] = {
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&ett_redbackli
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};
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proto_redbackli = proto_register_protocol("Redback Lawful Intercept",
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"RedbackLI","redbackli");
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proto_register_field_array(proto_redbackli,hf,array_length(hf));
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proto_register_subtree_array(ett,array_length(ett));
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register_dissector("redbackli", redbackli_dissect, proto_redbackli);
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}
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void proto_reg_handoff_redbackli(void) {
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dissector_handle_t redbackli_handle;
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ip_handle = find_dissector("ip");
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redbackli_handle = find_dissector("redbackli");
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dissector_add_handle("udp.port", redbackli_handle); /* for 'decode-as' */
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heur_dissector_add("udp", redbackli_dissect_heur, proto_redbackli);
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}
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