2 * Routines for lapb frame disassembly
3 * Olivier Abad <abad@daba.dhis.net>
5 * $Id: packet-lapb.c,v 1.9 1999/11/29 22:44:47 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>
43 static int proto_lapb = -1;
44 static int hf_lapb_address = -1;
45 static int hf_lapb_control = -1;
47 static gint ett_lapb = -1;
48 static gint ett_lapb_control = -1;
51 dissect_lapb(const u_char *pd, frame_data *fd, proto_tree *tree)
53 proto_tree *lapb_tree, *ti;
56 if (check_col(fd, COL_PROTOCOL))
57 col_add_str(fd, COL_PROTOCOL, "LAPB");
59 if(check_col(fd, COL_RES_DL_SRC))
60 col_add_fstr(fd, COL_RES_DL_SRC, "0x%02X", pd[0]);
61 if (pd[0] != 0x01 && pd[0] != 0x03) /* invalid LAPB frame */
63 if (check_col(fd, COL_INFO))
64 col_add_str(fd, COL_INFO, "Invalid LAPB frame");
66 ti = proto_tree_add_item_format(tree, proto_lapb, 0, fd->cap_len,
67 NULL, "Invalid LAPB frame");
71 if (fd->pseudo_header.x25.flags & FROM_DCE) {
72 if(check_col(fd, COL_RES_DL_DST))
73 col_add_str(fd, COL_RES_DL_DST, "DTE");
74 if(check_col(fd, COL_RES_DL_SRC))
75 col_add_str(fd, COL_RES_DL_SRC, "DCE");
78 if(check_col(fd, COL_RES_DL_DST))
79 col_add_str(fd, COL_RES_DL_DST, "DCE");
80 if(check_col(fd, COL_RES_DL_SRC))
81 col_add_str(fd, COL_RES_DL_SRC, "DTE");
84 if (((fd->pseudo_header.x25.flags & FROM_DCE) && pd[0] == 0x01) ||
85 (!(fd->pseudo_header.x25.flags & FROM_DCE) && pd[0] == 0x03))
91 ti = proto_tree_add_item_format(tree, proto_lapb, 0, 2, NULL,
93 lapb_tree = proto_item_add_subtree(ti, ett_lapb);
94 proto_tree_add_item_format(lapb_tree, hf_lapb_address, 0, 1, pd[0],
95 "Address: 0x%02X", pd[0]);
99 dissect_xdlc_control(pd, 1, fd, lapb_tree, hf_lapb_control,
100 ett_lapb_control, is_response, FALSE);
102 /* not end of frame ==> X.25 */
103 if (fd->cap_len > 2) dissect_x25(pd, 2, fd, tree);
107 proto_register_lapb(void)
109 static hf_register_info hf[] = {
111 { "Address Field", "lapb.address", FT_UINT8, BASE_DEC, NULL, 0x0,
115 { "Control Field", "lapb.control", FT_STRING, BASE_NONE, NULL, 0x0,
118 static gint *ett[] = {
123 proto_lapb = proto_register_protocol ("Link Access Procedure Balanced (LAPB)", "lapb");
124 proto_register_field_array (proto_lapb, hf, array_length(hf));
125 proto_register_subtree_array(ett, array_length(ett));