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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
/* packet-rlm.c
* Routines for RLM dissection
* Copyright 2004, Duncan Sargeant <dunc-ethereal@rcpt.to>
*
* $Id$
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
* 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.
*/
/*
* RLM is a proprietary Cisco protocol used for centralling managing
* many redundant NASes. I don't know much about the format, but you
* can read about the feature here:
*
* http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120t/120t3/rlm_123.htm
*
* RLM runs on a UDP port (default 3000) between the MGC and the NAS.
* On port N+1 (default 3001), a Q.931/LAPD/UDP connection is maintained.
* Both sides use the same local port number for the connection, so source
* and dest port are always the same.
*
* In large networks, the links are typically split onto higher ports,
* so anything up to 3015 (or higher) could either be RLM or Q.931 traffic,
* although always the RLM has the one lower port number for that RLM group.
*
* Multiple RLM groups are possible on a single NAS.
*
* I haven't been able to find the protocol documented, so I've
* guessed some of the fields based on the output of debug commands on
* cisco NASes.
*
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#include <epan/packet.h>
/* Initialize the protocol and registered fields */
static int proto_rlm = -1;
static int hf_rlm_version = -1;
static int hf_rlm_type = -1;
static int hf_rlm_unknown = -1;
static int hf_rlm_tid = -1;
static int hf_rlm_unknown2 = -1;
/* Initialize the subtree pointers */
static gint ett_rlm = -1;
/* RLM definitions - missing some! */
#define RLM_START_REQUEST 1
#define RLM_START_ACK 2
/* #define ??? 3 */
/* #define ??? 4 */
#define RLM_ECHO_REQUEST 5
#define RLM_ECHO_REPLY 6
/* #define ??? ?? */
/*
Maybe this isn't the best place for it, but RLM goes hand in hand
with Q.931 traffic on a higher port.
*/
static gboolean
dissect_udp_lapd(tvbuff_t *tvb, packet_info *pinfo _U_ , proto_tree *tree) {
if (pinfo->srcport < 3001 || pinfo->srcport > 3015
|| pinfo->destport < 3001 || pinfo->destport > 3015
|| pinfo->destport != pinfo->srcport)
return FALSE;
call_dissector(find_dissector("lapd"), tvb, pinfo, tree);
return TRUE;
}
/* Code to actually dissect the packets */
static gboolean
dissect_rlm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *ti;
proto_tree *rlm_tree;
guint8 rlm_type, version;
const char *type_str = NULL;
if (pinfo->srcport < 3000 || pinfo->srcport > 3015
|| pinfo->destport < 3000 || pinfo->destport > 3015
|| pinfo->destport != pinfo->srcport)
return FALSE;
version = tvb_get_guint8(tvb, 0);
rlm_type = tvb_get_guint8(tvb, 1);
/* we only know about version 2, and I've only seen 8 byte packets */
if (tvb_length(tvb) != 8 || version != 2) {
return FALSE;
}
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "RLM");
switch (rlm_type) {
case RLM_START_REQUEST:
type_str = "Start request";
break;;
case RLM_START_ACK:
type_str = "Start acknowledgement";
break;;
case RLM_ECHO_REQUEST:
type_str = "Echo request";
break;;
case RLM_ECHO_REPLY:
type_str = "Echo reply";
break;;
default:
type_str = "Unknown type";
break;;
}
if (check_col(pinfo->cinfo, COL_INFO))
col_set_str(pinfo->cinfo, COL_INFO, type_str);
if (tree) {
/* proto_tree_add_protocol_format(tree, proto_rlm, tvb, 0,
16, "Cisco Session Management"); */
ti = proto_tree_add_item(tree, proto_rlm, tvb, 0, 8, FALSE);
rlm_tree = proto_item_add_subtree(ti, ett_rlm);
ti = proto_tree_add_item(rlm_tree, hf_rlm_version, tvb, 0, 1, FALSE);
proto_tree_add_uint_format(rlm_tree, hf_rlm_type, tvb, 1, 1, rlm_type, "Type: %u (%s)", rlm_type, type_str);
ti = proto_tree_add_item(rlm_tree, hf_rlm_unknown, tvb, 2, 2, FALSE);
ti = proto_tree_add_item(rlm_tree, hf_rlm_tid, tvb, 4, 2, FALSE);
ti = proto_tree_add_item(rlm_tree, hf_rlm_unknown2, tvb, 6, 2, FALSE);
}
return TRUE;
}
/* Register the protocol with Ethereal */
/* this format is require because a script is used to build the C function
that calls all the protocol registration.
*/
void
proto_reg_handoff_rlm(void)
{
heur_dissector_add("udp", dissect_rlm, proto_rlm);
heur_dissector_add("udp", dissect_udp_lapd, proto_get_id_by_filter_name("lapd"));
}
void
proto_register_rlm(void)
{
/* Setup list of header fields See Section 1.6.1 for details*/
static hf_register_info hf[] = {
{ &hf_rlm_version,
{ "Version", "rlm.version",
FT_UINT8, BASE_DEC, NULL, 0x0,
"", HFILL }
},
{ &hf_rlm_type,
{ "Type", "rlm.type",
FT_UINT8, BASE_DEC, NULL, 0x0,
"", HFILL }
},
{ &hf_rlm_unknown,
{ "Unknown", "rlm.unknown",
FT_UINT16, BASE_HEX, NULL, 0x0,
"", HFILL }
},
{ &hf_rlm_tid,
{ "Transaction ID", "rlm.tid",
FT_UINT16, BASE_DEC, NULL, 0x0,
"", HFILL }
},
{ &hf_rlm_unknown2,
{ "Unknown", "rlm.unknown2",
FT_UINT16, BASE_HEX, NULL, 0x0,
"", HFILL }
},
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_rlm,
};
/* Register the protocol name and description */
proto_rlm = proto_register_protocol("Redundant Link Management Protocol",
"RLM", "rlm");
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_rlm, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
|
