2 * Routines for lapb frame disassembly
3 * Olivier Abad <abad@daba.dhis.net>
5 * $Id: packet-lapb.c,v 1.11 2000/03/12 04:47:42 gram 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>
39 #include "packet-x25.h"
44 static int proto_lapb = -1;
45 static int hf_lapb_address = -1;
46 static int hf_lapb_control = -1;
48 static gint ett_lapb = -1;
49 static gint ett_lapb_control = -1;
52 dissect_lapb(const u_char *pd, frame_data *fd, proto_tree *tree)
54 proto_tree *lapb_tree, *ti;
57 if (check_col(fd, COL_PROTOCOL))
58 col_add_str(fd, COL_PROTOCOL, "LAPB");
60 if(check_col(fd, COL_RES_DL_SRC))
61 col_add_fstr(fd, COL_RES_DL_SRC, "0x%02X", pd[0]);
62 if (pd[0] != 0x01 && pd[0] != 0x03) /* invalid LAPB frame */
64 if (check_col(fd, COL_INFO))
65 col_add_str(fd, COL_INFO, "Invalid LAPB frame");
67 ti = proto_tree_add_protocol_format(tree, proto_lapb, 0, fd->cap_len,
68 "Invalid LAPB frame");
72 if (fd->pseudo_header.x25.flags & FROM_DCE) {
73 if(check_col(fd, COL_RES_DL_DST))
74 col_add_str(fd, COL_RES_DL_DST, "DTE");
75 if(check_col(fd, COL_RES_DL_SRC))
76 col_add_str(fd, COL_RES_DL_SRC, "DCE");
79 if(check_col(fd, COL_RES_DL_DST))
80 col_add_str(fd, COL_RES_DL_DST, "DCE");
81 if(check_col(fd, COL_RES_DL_SRC))
82 col_add_str(fd, COL_RES_DL_SRC, "DTE");
85 if (((fd->pseudo_header.x25.flags & FROM_DCE) && pd[0] == 0x01) ||
86 (!(fd->pseudo_header.x25.flags & FROM_DCE) && pd[0] == 0x03))
92 ti = proto_tree_add_protocol_format(tree, proto_lapb, 0, 2,
94 lapb_tree = proto_item_add_subtree(ti, ett_lapb);
95 proto_tree_add_uint_format(lapb_tree, hf_lapb_address, 0, 1, pd[0],
96 "Address: 0x%02X", pd[0]);
100 dissect_xdlc_control(pd, 1, fd, lapb_tree, hf_lapb_control,
101 ett_lapb_control, is_response, FALSE);
103 /* not end of frame ==> X.25 */
104 if (fd->cap_len > 2) dissect_x25(pd, 2, fd, tree);
108 proto_register_lapb(void)
110 static hf_register_info hf[] = {
112 { "Address Field", "lapb.address", FT_UINT8, BASE_HEX, NULL, 0x0,
116 { "Control Field", "lapb.control", FT_STRING, BASE_NONE, NULL, 0x0,
119 static gint *ett[] = {
124 proto_lapb = proto_register_protocol ("Link Access Procedure Balanced (LAPB)", "lapb");
125 proto_register_field_array (proto_lapb, hf, array_length(hf));
126 proto_register_subtree_array(ett, array_length(ett));