298 lines
8.1 KiB
C
298 lines
8.1 KiB
C
/* packet-redbackli.c
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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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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <epan/packet.h>
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void proto_register_redbackli(void);
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void proto_reg_handoff_redbackli(void);
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static int proto_redbackli = -1;
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static int hf_redbackli_avptype = -1;
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static int hf_redbackli_avplen = -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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static dissector_handle_t redbackli_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 *st = NULL;
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avpname = val_to_str_const(avptype, avp_names, "Unknown");
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st = proto_tree_add_subtree_format(tree, tvb, offset, avplen+2, ett_redbackli, NULL, "%s AVP", avpname);
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proto_tree_add_uint(st, hf_redbackli_avptype, tvb, offset, 1, avptype);
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proto_tree_add_uint(st, hf_redbackli_avplen, tvb, offset+1, 1, 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 int
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redbackli_dissect(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
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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_item *ti;
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proto_tree *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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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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len = tvb_reported_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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return tvb_captured_length(tvb);
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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_captured_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, data);
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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_avptype,
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{ "AVP Type", "redbackli.avptype", FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_redbackli_avplen,
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{ "AVP Length", "redbackli.avplen", FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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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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#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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{ &hf_redbackli_dir,
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{ "Direction", "redbackli.dir", FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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#else
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{ &hf_redbackli_dir,
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{ "Direction", "redbackli.dir", FT_BYTES, BASE_NONE, NULL, 0x0,
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NULL, HFILL }},
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#endif
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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", "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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redbackli_handle = 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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ip_handle = find_dissector_add_dependency("ip", proto_redbackli);
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dissector_add_for_decode_as_with_preference("udp.port", redbackli_handle);
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heur_dissector_add("udp", redbackli_dissect_heur, "Redback Lawful Intercept over UDP", "redbackli_udp", proto_redbackli, HEURISTIC_ENABLE);
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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