2 * Routines for v120 frame disassembly
3 * Bert Driehuis <driehuis@playbeing.org>
5 * $Id: packet-v120.c,v 1.19 2001/06/18 02:17:53 guy Exp $
7 * Ethereal - Network traffic analyzer
8 * By Gerald Combs <gerald@zing.org>
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version 2
15 * of the License, or (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
31 #ifdef HAVE_SYS_TYPES_H
32 # include <sys/types.h>
43 static int proto_v120 = -1;
44 static int hf_v120_address = -1;
45 static int hf_v120_control = -1;
46 static int hf_v120_header = -1;
48 static gint ett_v120 = -1;
49 static gint ett_v120_address = -1;
50 static gint ett_v120_control = -1;
51 static gint ett_v120_header = -1;
53 static int dissect_v120_header(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree);
56 dissect_v120(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
58 proto_tree *v120_tree, *tc, *address_tree;
68 if (check_col(pinfo->fd, COL_PROTOCOL))
69 col_set_str(pinfo->fd, COL_PROTOCOL, "V.120");
70 if (check_col(pinfo->fd, COL_INFO))
71 col_clear(pinfo->fd, COL_INFO);
73 byte0 = tvb_get_guint8(tvb, 0);
75 if(check_col(pinfo->fd, COL_RES_DL_SRC))
76 col_add_fstr(pinfo->fd, COL_RES_DL_SRC, "0x%02X", byte0);
78 byte1 = tvb_get_guint8(tvb, 1);
80 if ((byte0 & 0x01) != 0x00 && (byte1 && 0x01) != 0x01)
82 if (check_col(pinfo->fd, COL_INFO))
83 col_set_str(pinfo->fd, COL_INFO, "Invalid V.120 frame");
85 ti = proto_tree_add_protocol_format(tree, proto_v120, tvb, 0, tvb_length(tvb),
86 "Invalid V.120 frame");
90 if (pinfo->pseudo_header->x25.flags & FROM_DCE) {
91 if(check_col(pinfo->fd, COL_RES_DL_DST))
92 col_set_str(pinfo->fd, COL_RES_DL_DST, "DTE");
93 if(check_col(pinfo->fd, COL_RES_DL_SRC))
94 col_set_str(pinfo->fd, COL_RES_DL_SRC, "DCE");
97 if(check_col(pinfo->fd, COL_RES_DL_DST))
98 col_set_str(pinfo->fd, COL_RES_DL_DST, "DCE");
99 if(check_col(pinfo->fd, COL_RES_DL_SRC))
100 col_set_str(pinfo->fd, COL_RES_DL_SRC, "DTE");
103 if (((pinfo->pseudo_header->x25.flags & FROM_DCE) && byte0 & 0x02) ||
104 (!(pinfo->pseudo_header->x25.flags & FROM_DCE) && !(byte0 & 0x02)))
110 ti = proto_tree_add_protocol_format(tree, proto_v120, tvb, 0, 0, "V.120");
111 v120_tree = proto_item_add_subtree(ti, ett_v120);
112 addr = byte1 << 8 | byte0;
113 sprintf(info, "LLI: %d C/R: %s",
114 ((byte0 & 0xfc) << 5) | ((byte1 & 0xfe) >> 1),
115 byte0 & 0x02 ? "R" : "C");
116 tc = proto_tree_add_text(v120_tree, tvb,
118 "Address field: %s", info);
119 address_tree = proto_item_add_subtree(tc, ett_v120_address);
120 proto_tree_add_text(address_tree, tvb, 0, 2,
121 decode_boolean_bitfield(addr, 0x0002, 2*8,
122 "Response", "Command"), NULL);
123 sprintf(info, "LLI: %d", ((byte0 & 0xfc) << 5) | ((byte1 & 0xfe) >> 1));
124 proto_tree_add_text(address_tree, tvb, 0, 2,
125 decode_numeric_bitfield(addr, 0xfefc, 2*8, info));
126 proto_tree_add_text(address_tree, tvb, 0, 2,
127 decode_boolean_bitfield(addr, 0x0001, 2*8,
128 "EA0 = 1 (Error)", "EA0 = 0"), NULL);
129 proto_tree_add_text(address_tree, tvb, 0, 2,
130 decode_boolean_bitfield(addr, 0x0100, 2*8,
131 "EA1 = 1", "EA1 = 0 (Error)"), NULL);
137 control = dissect_xdlc_control(tvb, 2, pinfo, v120_tree, hf_v120_control,
138 ett_v120_control, is_response, TRUE);
140 v120len = 2 + XDLC_CONTROL_LEN(control, TRUE);
141 if (tvb_bytes_exist(tvb, v120len, 1))
142 v120len += dissect_v120_header(tvb, v120len, pinfo, v120_tree);
143 proto_item_set_len(ti, v120len);
144 next_tvb = tvb_new_subset(tvb, v120len, -1, -1);
145 dissect_data(next_tvb, 0, pinfo, v120_tree);
150 dissect_v120_header(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree)
153 int header_len, nbits;
155 proto_tree *h_tree, *tc;
158 byte0 = tvb_get_guint8(tvb, offset);
165 header = byte0 | tvb_get_guint8(tvb, offset + 1) << 8;
167 nbits = header_len * 8;
168 sprintf(info, "Header: B: %d F: %d", byte0 & 0x02 ? 1:0,
170 tc = proto_tree_add_text(tree, tvb,
172 "Header octet: %s (0x%02X)", info, byte0);
173 h_tree = proto_item_add_subtree(tc, ett_v120_header);
174 proto_tree_add_text(h_tree, tvb, offset, header_len,
175 decode_boolean_bitfield(header, 0x80, nbits,
176 "No extension octet", "Extension octet follows"), NULL);
177 proto_tree_add_text(h_tree, tvb, offset, header_len,
178 decode_boolean_bitfield(header, 0x40, nbits,
179 "Break condition", "No break condition"), NULL);
180 sprintf(info, "Error control C1/C2: %d", (header & 0x0c) >> 2);
181 proto_tree_add_text(h_tree, tvb, offset, header_len,
182 decode_numeric_bitfield(header, 0x0c, nbits, info));
183 proto_tree_add_text(h_tree, tvb, offset, header_len,
184 decode_boolean_bitfield(header, 0x02, nbits,
185 "Segmentation bit B", "No segmentation bit B"), NULL);
186 proto_tree_add_text(h_tree, tvb, offset, header_len,
187 decode_boolean_bitfield(header, 0x01, nbits,
188 "Segmentation bit F", "No segmentation bit F"), NULL);
189 if (header_len == 2) {
190 proto_tree_add_text(h_tree, tvb, offset, header_len,
191 decode_boolean_bitfield(header, 0x8000, nbits,
192 "E", "E bit not set (Error)"), NULL);
193 proto_tree_add_text(h_tree, tvb, offset, header_len,
194 decode_boolean_bitfield(header, 0x4000, nbits,
195 "DR", "No DR"), NULL);
196 proto_tree_add_text(h_tree, tvb, offset, header_len,
197 decode_boolean_bitfield(header, 0x2000, nbits,
198 "SR", "No SR"), NULL);
199 proto_tree_add_text(h_tree, tvb, offset, header_len,
200 decode_boolean_bitfield(header, 0x1000, nbits,
201 "RR", "No RR"), NULL);
207 proto_register_v120(void)
209 static hf_register_info hf[] = {
211 { "Link Address", "v120.address", FT_UINT16, BASE_HEX, NULL,
214 { "Control Field", "v120.control", FT_UINT16, BASE_HEX, NULL, 0x0,
217 { "Header Field", "v120.header", FT_STRING, BASE_NONE, NULL, 0x0,
220 static gint *ett[] = {
227 proto_v120 = proto_register_protocol("Async data over ISDN (V.120)",
229 proto_register_field_array (proto_v120, hf, array_length(hf));
230 proto_register_subtree_array(ett, array_length(ett));
234 proto_reg_handoff_v120(void)
236 dissector_add("wtap_encap", WTAP_ENCAP_V120, dissect_v120,