forked from osmocom/wireshark
135 lines
3.6 KiB
C
135 lines
3.6 KiB
C
/* atm.c
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*
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* Wiretap Library
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* Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
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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 "wtap-int.h"
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#include "atm.h"
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/*
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* Routines to use with ATM capture file types that don't include information
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* about the *type* of ATM traffic (or, at least, where we haven't found
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* that information).
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*
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* We assume the traffic is AAL5, unless it's VPI 0/VCI 5, in which case
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* we assume it's the signalling AAL.
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*/
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void
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atm_guess_traffic_type(wtap_rec *rec, const guint8 *pd)
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{
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/*
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* Start out assuming nothing other than that it's AAL5.
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*/
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rec->rec_header.packet_header.pseudo_header.atm.aal = AAL_5;
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rec->rec_header.packet_header.pseudo_header.atm.type = TRAF_UNKNOWN;
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rec->rec_header.packet_header.pseudo_header.atm.subtype = TRAF_ST_UNKNOWN;
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if (rec->rec_header.packet_header.pseudo_header.atm.vpi == 0) {
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/*
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* Traffic on some PVCs with a VPI of 0 and certain
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* VCIs is of particular types.
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*/
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switch (rec->rec_header.packet_header.pseudo_header.atm.vci) {
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case 5:
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/*
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* Signalling AAL.
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*/
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rec->rec_header.packet_header.pseudo_header.atm.aal = AAL_SIGNALLING;
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return;
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case 16:
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/*
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* ILMI.
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*/
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rec->rec_header.packet_header.pseudo_header.atm.type = TRAF_ILMI;
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return;
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}
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}
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/*
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* OK, we can't tell what it is based on the VPI/VCI; try
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* guessing based on the contents, if we have enough data
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* to guess.
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*/
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if (rec->rec_header.packet_header.caplen >= 3) {
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if (pd[0] == 0xaa && pd[1] == 0xaa && pd[2] == 0x03) {
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/*
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* Looks like a SNAP header; assume it's LLC
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* multiplexed RFC 1483 traffic.
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*/
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rec->rec_header.packet_header.pseudo_header.atm.type = TRAF_LLCMX;
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} else if ((rec->rec_header.packet_header.pseudo_header.atm.aal5t_len && rec->rec_header.packet_header.pseudo_header.atm.aal5t_len < 16) ||
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rec->rec_header.packet_header.caplen < 16) {
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/*
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* As this cannot be a LANE Ethernet frame (less
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* than 2 bytes of LANE header + 14 bytes of
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* Ethernet header) we can try it as a SSCOP frame.
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*/
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rec->rec_header.packet_header.pseudo_header.atm.aal = AAL_SIGNALLING;
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} else if (pd[0] == 0x83 || pd[0] == 0x81) {
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/*
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* MTP3b headers often encapsulate
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* a SCCP or MTN in the 3G network.
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* This should cause 0x83 or 0x81
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* in the first byte.
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*/
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rec->rec_header.packet_header.pseudo_header.atm.aal = AAL_SIGNALLING;
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} else {
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/*
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* Assume it's LANE.
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*/
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rec->rec_header.packet_header.pseudo_header.atm.type = TRAF_LANE;
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atm_guess_lane_type(rec, pd);
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}
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} else {
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/*
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* Not only VCI 5 is used for signaling. It might be
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* one of these VCIs.
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*/
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rec->rec_header.packet_header.pseudo_header.atm.aal = AAL_SIGNALLING;
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}
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}
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void
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atm_guess_lane_type(wtap_rec *rec, const guint8 *pd)
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{
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if (rec->rec_header.packet_header.caplen >= 2) {
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if (pd[0] == 0xff && pd[1] == 0x00) {
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/*
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* Looks like LE Control traffic.
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*/
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rec->rec_header.packet_header.pseudo_header.atm.subtype = TRAF_ST_LANE_LE_CTRL;
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} else {
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/*
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* XXX - Ethernet, or Token Ring?
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* Assume Ethernet for now; if we see earlier
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* LANE traffic, we may be able to figure out
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* the traffic type from that, but there may
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* still be situations where the user has to
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* tell us.
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*/
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rec->rec_header.packet_header.pseudo_header.atm.subtype = TRAF_ST_LANE_802_3;
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}
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}
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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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