aboutsummaryrefslogtreecommitdiffstats
path: root/wiretap/atm.c
blob: 83789e9c225e85b0f0fbe6de84fb9d8d9cd6afca (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
/* atm.c
 *
 * Wiretap Library
 * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"
#include "wtap-int.h"
#include "atm.h"

/*
 * Routines to use with ATM capture file types that don't include information
 * about the *type* of ATM traffic (or, at least, where we haven't found
 * that information).
 *
 * We assume the traffic is AAL5, unless it's VPI 0/VCI 5, in which case
 * we assume it's the signalling AAL.
 */

void
atm_guess_traffic_type(struct wtap_pkthdr *phdr, const guint8 *pd)
{
	/*
	 * Start out assuming nothing other than that it's AAL5.
	 */
	phdr->pseudo_header.atm.aal = AAL_5;
	phdr->pseudo_header.atm.type = TRAF_UNKNOWN;
	phdr->pseudo_header.atm.subtype = TRAF_ST_UNKNOWN;

	if (phdr->pseudo_header.atm.vpi == 0) {
		/*
		 * Traffic on some PVCs with a VPI of 0 and certain
		 * VCIs is of particular types.
		 */
		switch (phdr->pseudo_header.atm.vci) {

		case 5:
			/*
			 * Signalling AAL.
			 */
			phdr->pseudo_header.atm.aal = AAL_SIGNALLING;
			return;

		case 16:
			/*
			 * ILMI.
			 */
			phdr->pseudo_header.atm.type = TRAF_ILMI;
			return;
		}
	}

	/*
	 * OK, we can't tell what it is based on the VPI/VCI; try
	 * guessing based on the contents, if we have enough data
	 * to guess.
	 */

	if (phdr->caplen >= 3) {
		if (pd[0] == 0xaa && pd[1] == 0xaa && pd[2] == 0x03) {
			/*
			 * Looks like a SNAP header; assume it's LLC
			 * multiplexed RFC 1483 traffic.
			 */
			phdr->pseudo_header.atm.type = TRAF_LLCMX;
		} else if ((phdr->pseudo_header.atm.aal5t_len && phdr->pseudo_header.atm.aal5t_len < 16) ||
		    phdr->caplen < 16) {
			/*
			 * As this cannot be a LANE Ethernet frame (less
			 * than 2 bytes of LANE header + 14 bytes of
			 * Ethernet header) we can try it as a SSCOP frame.
			 */
			phdr->pseudo_header.atm.aal = AAL_SIGNALLING;
		} else if (pd[0] == 0x83 || pd[0] == 0x81) {
			/*
			 * MTP3b headers often encapsulate
			 * a SCCP or MTN in the 3G network.
			 * This should cause 0x83 or 0x81
			 * in the first byte.
			 */
			phdr->pseudo_header.atm.aal = AAL_SIGNALLING;
		} else {
			/*
			 * Assume it's LANE.
			 */
			phdr->pseudo_header.atm.type = TRAF_LANE;
			atm_guess_lane_type(phdr, pd);
		}
	} else {
	       /*
		* Not only VCI 5 is used for signaling. It might be
		* one of these VCIs.
		*/
	       phdr->pseudo_header.atm.aal = AAL_SIGNALLING;
	}
}

void
atm_guess_lane_type(struct wtap_pkthdr *phdr, const guint8 *pd)
{
	if (phdr->caplen >= 2) {
		if (pd[0] == 0xff && pd[1] == 0x00) {
			/*
			 * Looks like LE Control traffic.
			 */
			phdr->pseudo_header.atm.subtype = TRAF_ST_LANE_LE_CTRL;
		} else {
			/*
			 * XXX - Ethernet, or Token Ring?
			 * Assume Ethernet for now; if we see earlier
			 * LANE traffic, we may be able to figure out
			 * the traffic type from that, but there may
			 * still be situations where the user has to
			 * tell us.
			 */
			phdr->pseudo_header.atm.subtype = TRAF_ST_LANE_802_3;
		}
	}
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */