2 * Routines for v120 frame disassembly
3 * Bert Driehuis <driehuis@playbeing.org>
5 * $Id: packet-v120.c,v 1.31 2003/09/02 19:18:52 guy Exp $
7 * Ethereal - Network traffic analyzer
8 * By Gerald Combs <gerald@ethereal.com>
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version 2
14 * of the License, or (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
33 #include <epan/packet.h>
36 static int proto_v120 = -1;
37 static int hf_v120_address = -1;
38 static int hf_v120_control = -1;
39 static int hf_v120_header = -1;
41 static gint ett_v120 = -1;
42 static gint ett_v120_address = -1;
43 static gint ett_v120_control = -1;
44 static gint ett_v120_header = -1;
46 static dissector_handle_t data_handle;
48 static int dissect_v120_header(tvbuff_t *tvb, int offset, proto_tree *tree);
51 dissect_v120(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
53 proto_tree *v120_tree, *tc, *address_tree;
63 if (check_col(pinfo->cinfo, COL_PROTOCOL))
64 col_set_str(pinfo->cinfo, COL_PROTOCOL, "V.120");
65 if (check_col(pinfo->cinfo, COL_INFO))
66 col_clear(pinfo->cinfo, COL_INFO);
68 byte0 = tvb_get_guint8(tvb, 0);
70 if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
71 col_add_fstr(pinfo->cinfo, COL_RES_DL_SRC, "0x%02X", byte0);
73 byte1 = tvb_get_guint8(tvb, 1);
75 if ((byte0 & 0x01) != 0x00 && (byte1 && 0x01) != 0x01)
77 if (check_col(pinfo->cinfo, COL_INFO))
78 col_set_str(pinfo->cinfo, COL_INFO, "Invalid V.120 frame");
80 ti = proto_tree_add_protocol_format(tree, proto_v120, tvb, 0, -1,
81 "Invalid V.120 frame");
85 if (pinfo->p2p_dir == P2P_DIR_SENT) {
86 is_response = (byte0 & 0x02) ? FALSE: TRUE;
87 if(check_col(pinfo->cinfo, COL_RES_DL_DST))
88 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE");
89 if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
90 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE");
92 /* XXX - what if the direction is unknown? */
93 is_response = (byte0 & 0x02) ? TRUE : FALSE;
94 if(check_col(pinfo->cinfo, COL_RES_DL_DST))
95 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE");
96 if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
97 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE");
101 ti = proto_tree_add_protocol_format(tree, proto_v120, tvb, 0, -1, "V.120");
102 v120_tree = proto_item_add_subtree(ti, ett_v120);
103 addr = byte1 << 8 | byte0;
104 sprintf(info, "LLI: %d C/R: %s",
105 ((byte0 & 0xfc) << 5) | ((byte1 & 0xfe) >> 1),
106 byte0 & 0x02 ? "R" : "C");
107 tc = proto_tree_add_text(v120_tree, tvb,
109 "Address field: %s", info);
110 address_tree = proto_item_add_subtree(tc, ett_v120_address);
111 proto_tree_add_text(address_tree, tvb, 0, 2,
112 decode_boolean_bitfield(addr, 0x0002, 2*8,
113 "Response", "Command"), NULL);
114 sprintf(info, "LLI: %d", ((byte0 & 0xfc) << 5) | ((byte1 & 0xfe) >> 1));
115 proto_tree_add_text(address_tree, tvb, 0, 2,
116 decode_numeric_bitfield(addr, 0xfefc, 2*8, info));
117 proto_tree_add_text(address_tree, tvb, 0, 2,
118 decode_boolean_bitfield(addr, 0x0001, 2*8,
119 "EA0 = 1 (Error)", "EA0 = 0"), NULL);
120 proto_tree_add_text(address_tree, tvb, 0, 2,
121 decode_boolean_bitfield(addr, 0x0100, 2*8,
122 "EA1 = 1", "EA1 = 0 (Error)"), NULL);
128 control = dissect_xdlc_control(tvb, 2, pinfo, v120_tree, hf_v120_control,
129 ett_v120_control, is_response, TRUE, FALSE);
131 v120len = 2 + XDLC_CONTROL_LEN(control, TRUE);
132 if (tvb_bytes_exist(tvb, v120len, 1))
133 v120len += dissect_v120_header(tvb, v120len, v120_tree);
134 proto_item_set_len(ti, v120len);
135 next_tvb = tvb_new_subset(tvb, v120len, -1, -1);
136 call_dissector(data_handle,next_tvb, pinfo, v120_tree);
141 dissect_v120_header(tvbuff_t *tvb, int offset, proto_tree *tree)
144 int header_len, nbits;
146 proto_tree *h_tree, *tc;
149 byte0 = tvb_get_guint8(tvb, offset);
156 header = byte0 | tvb_get_guint8(tvb, offset + 1) << 8;
158 nbits = header_len * 8;
159 sprintf(info, "Header: B: %d F: %d", byte0 & 0x02 ? 1:0,
161 tc = proto_tree_add_text(tree, tvb,
163 "Header octet: %s (0x%02X)", info, byte0);
164 h_tree = proto_item_add_subtree(tc, ett_v120_header);
165 proto_tree_add_text(h_tree, tvb, offset, header_len,
166 decode_boolean_bitfield(header, 0x80, nbits,
167 "No extension octet", "Extension octet follows"), NULL);
168 proto_tree_add_text(h_tree, tvb, offset, header_len,
169 decode_boolean_bitfield(header, 0x40, nbits,
170 "Break condition", "No break condition"), NULL);
171 sprintf(info, "Error control C1/C2: %d", (header & 0x0c) >> 2);
172 proto_tree_add_text(h_tree, tvb, offset, header_len,
173 decode_numeric_bitfield(header, 0x0c, nbits, info));
174 proto_tree_add_text(h_tree, tvb, offset, header_len,
175 decode_boolean_bitfield(header, 0x02, nbits,
176 "Segmentation bit B", "No segmentation bit B"), NULL);
177 proto_tree_add_text(h_tree, tvb, offset, header_len,
178 decode_boolean_bitfield(header, 0x01, nbits,
179 "Segmentation bit F", "No segmentation bit F"), NULL);
180 if (header_len == 2) {
181 proto_tree_add_text(h_tree, tvb, offset, header_len,
182 decode_boolean_bitfield(header, 0x8000, nbits,
183 "E", "E bit not set (Error)"), NULL);
184 proto_tree_add_text(h_tree, tvb, offset, header_len,
185 decode_boolean_bitfield(header, 0x4000, nbits,
186 "DR", "No DR"), NULL);
187 proto_tree_add_text(h_tree, tvb, offset, header_len,
188 decode_boolean_bitfield(header, 0x2000, nbits,
189 "SR", "No SR"), NULL);
190 proto_tree_add_text(h_tree, tvb, offset, header_len,
191 decode_boolean_bitfield(header, 0x1000, nbits,
192 "RR", "No RR"), NULL);
198 proto_register_v120(void)
200 static hf_register_info hf[] = {
202 { "Link Address", "v120.address", FT_UINT16, BASE_HEX, NULL,
205 { "Control Field", "v120.control", FT_UINT16, BASE_HEX, NULL, 0x0,
208 { "Header Field", "v120.header", FT_STRING, BASE_NONE, NULL, 0x0,
211 static gint *ett[] = {
218 proto_v120 = proto_register_protocol("Async data over ISDN (V.120)",
220 proto_register_field_array (proto_v120, hf, array_length(hf));
221 proto_register_subtree_array(ett, array_length(ett));
223 register_dissector("v120", dissect_v120, proto_v120);
227 proto_reg_handoff_v120(void)
229 data_handle = find_dissector("data");