packet-v120.c

   1 /* packet-v120.c
   2  * Routines for v120 frame disassembly
   3  * Bert Driehuis <driehuis@playbeing.org>
   4  *
   5  * $Id: packet-v120.c,v 1.3 1999/12/14 06:21:19 guy Exp $
   6  *
   7  * Ethereal - Network traffic analyzer
   8  * By Gerald Combs <gerald@zing.org>
   9  * Copyright 1998
  10  *
  11  *
  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.
  16  *
  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.
  21  *
  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.
  25  */
  26
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #ifdef HAVE_SYS_TYPES_H
  32 # include <sys/types.h>
  33 #endif
  34
  35 #include <stdio.h>
  36 #include <glib.h>
  37 #include <string.h>
  38 #include "packet.h"
  39 #include "xdlc.h"
  40
  41 #define FROM_DCE        0x80
  42
  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;
  47
  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;
  52
  53 void dissect_v120_header(const u_char *pd, int offset, frame_data *fd, proto_tree *tree);
  54
  55 void
  56 dissect_v120(const u_char *pd, frame_data *fd, proto_tree *tree)
  57 {
  58     proto_tree *v120_tree, *ti, *tc, *address_tree;
  59     int is_response;
  60     int addr;
  61     char info[80];
  62     int v120len;
  63
  64     if (check_col(fd, COL_PROTOCOL))
  65         col_add_str(fd, COL_PROTOCOL, "V.120");
  66
  67     if(check_col(fd, COL_RES_DL_SRC))
  68         col_add_fstr(fd, COL_RES_DL_SRC, "0x%02X", pd[0]);
  69     if ((pd[0] & 0x01) != 0x00 && (pd[1] && 0x01) != 0x01)
  70     {
  71         if (check_col(fd, COL_INFO))
  72             col_add_str(fd, COL_INFO, "Invalid V.120 frame");
  73         if (tree)
  74             ti = proto_tree_add_item_format(tree, proto_v120, 0, fd->cap_len,
  75                                             NULL, "Invalid V.120 frame");
  76         return;
  77     }
  78
  79     if (fd->pseudo_header.x25.flags & FROM_DCE) {
  80         if(check_col(fd, COL_RES_DL_DST))
  81             col_add_str(fd, COL_RES_DL_DST, "DTE");
  82         if(check_col(fd, COL_RES_DL_SRC))
  83             col_add_str(fd, COL_RES_DL_SRC, "DCE");
  84     }
  85     else {
  86         if(check_col(fd, COL_RES_DL_DST))
  87             col_add_str(fd, COL_RES_DL_DST, "DCE");
  88         if(check_col(fd, COL_RES_DL_SRC))
  89             col_add_str(fd, COL_RES_DL_SRC, "DTE");
  90     }
  91
  92     if (((fd->pseudo_header.x25.flags & FROM_DCE) && pd[0] & 0x02) ||
  93        (!(fd->pseudo_header.x25.flags & FROM_DCE) && !(pd[0] & 0x02)))
  94         is_response = TRUE;
  95     else
  96         is_response = FALSE;
  97
  98     if (fd->pkt_len <= 5)
  99         v120len = fd->pkt_len;
 100     else
 101         v120len = 5;
 102     if (tree) {
 103         ti = proto_tree_add_item_format(tree, proto_v120, 0, v120len, NULL,
 104                                             "V.120");
 105         v120_tree = proto_item_add_subtree(ti, ett_v120);
 106         addr = pd[1] << 8 | pd[0];
 107         sprintf(info, "LLI: %d C/R: %s",
 108                         ((pd[0] & 0xfc) << 5) | ((pd[1] & 0xfe) >> 1),
 109                         pd[0] & 0x02 ? "R" : "C");
 110         tc = proto_tree_add_item_format(v120_tree, ett_v120_address,
 111                         0, 2,
 112                         "Address field: %s", info);
 113         address_tree = proto_item_add_subtree(tc, ett_v120_address);
 114         proto_tree_add_text(address_tree, 0, 2,
 115                     decode_boolean_bitfield(addr, 0x0002, 2*8,
 116                         "Response", "Command"), NULL);
 117         sprintf(info, "LLI: %d", ((pd[0] & 0xfc) << 5) | ((pd[1] & 0xfe) >> 1));
 118         proto_tree_add_text(address_tree, 0, 2,
 119                     decode_numeric_bitfield(addr, 0xfefc, 2*8, info));
 120         proto_tree_add_text(address_tree, 0, 2,
 121                     decode_boolean_bitfield(addr, 0x0001, 2*8,
 122                         "EA0 = 1 (Error)", "EA0 = 0"), NULL);
 123         proto_tree_add_text(address_tree, 0, 2,
 124                     decode_boolean_bitfield(addr, 0x0100, 2*8,
 125                         "EA1 = 1", "EA1 = 0 (Error)"), NULL);
 126         if (v120len == 5)
 127                 dissect_v120_header(pd, 4, fd, v120_tree);
 128     }
 129     else
 130         v120_tree = NULL;
 131     dissect_xdlc_control(pd, 2, fd, v120_tree, hf_v120_control,
 132             ett_v120_control, is_response, v120len == 3 ? FALSE : TRUE);
 133 }
 134
 135 void
 136 dissect_v120_header(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 137 {
 138         char info[80];
 139         int header_len, nbits;
 140         int header;
 141         proto_tree *h_tree, *tc;
 142
 143         if (pd[offset] & 0x80) {
 144                 header_len = 1;
 145                 header = pd[offset];
 146         } else {
 147                 header_len = 2;
 148                 header = pd[offset] | pd[offset + 1] << 8;
 149         }
 150         nbits = header_len * 8;
 151         sprintf(info, "Header: B: %d F: %d", pd[offset] & 0x02 ? 1:0,
 152                         pd[offset] & 0x01 ? 1:0);
 153         tc = proto_tree_add_item_format(tree, ett_v120_header,
 154                         offset, header_len,
 155                         "Header octet: %s (0x%02X)", info, pd[offset]);
 156         h_tree = proto_item_add_subtree(tc, ett_v120_header);
 157         proto_tree_add_text(h_tree, offset, header_len,
 158                     decode_boolean_bitfield(header, 0x80, nbits,
 159                         "No extension octet", "Extension octet follows"), NULL);
 160         proto_tree_add_text(h_tree, offset, header_len,
 161                     decode_boolean_bitfield(header, 0x40, nbits,
 162                         "Break condition", "No break condition"), NULL);
 163         sprintf(info, "Error control C1/C2: %d", (header & 0x0c) >> 2);
 164         proto_tree_add_text(h_tree, offset, header_len,
 165                     decode_numeric_bitfield(header, 0x0c, nbits, info));
 166         proto_tree_add_text(h_tree, offset, header_len,
 167                     decode_boolean_bitfield(header, 0x02, nbits,
 168                         "Segmentation bit B", "No segmentation bit B"), NULL);
 169         proto_tree_add_text(h_tree, offset, header_len,
 170                     decode_boolean_bitfield(header, 0x01, nbits,
 171                         "Segmentation bit F", "No segmentation bit F"), NULL);
 172         if (header_len == 2) {
 173                 proto_tree_add_text(h_tree, offset, header_len,
 174                     decode_boolean_bitfield(header, 0x8000, nbits,
 175                         "E", "E bit not set (Error)"), NULL);
 176                 proto_tree_add_text(h_tree, offset, header_len,
 177                     decode_boolean_bitfield(header, 0x4000, nbits,
 178                         "DR", "No DR"), NULL);
 179                 proto_tree_add_text(h_tree, offset, header_len,
 180                     decode_boolean_bitfield(header, 0x2000, nbits,
 181                         "SR", "No SR"), NULL);
 182                 proto_tree_add_text(h_tree, offset, header_len,
 183                     decode_boolean_bitfield(header, 0x1000, nbits,
 184                         "RR", "No RR"), NULL);
 185         }
 186 }
 187 void
 188 proto_register_v120(void)
 189 {
 190     static hf_register_info hf[] = {
 191         { &hf_v120_address,
 192           { "Link Address", "v120.address", FT_UINT16, BASE_HEX, NULL,
 193                   0x0, "" }},
 194         { &hf_v120_control,
 195           { "Control Field", "v120.control", FT_STRING, BASE_NONE, NULL, 0x0,
 196                 "" }},
 197         { &hf_v120_header,
 198           { "Header Field", "v120.header", FT_STRING, BASE_NONE, NULL, 0x0,
 199                 "" }},
 200     };
 201     static gint *ett[] = {
 202         &ett_v120,
 203         &ett_v120_address,
 204         &ett_v120_control,
 205         &ett_v120_header,
 206     };
 207
 208     proto_v120 = proto_register_protocol ("Async data over ISDN (V.120)", "v120");
 209     proto_register_field_array (proto_v120, hf, array_length(hf));
 210     proto_register_subtree_array(ett, array_length(ett));
 211 }