epan/dissectors/packet-ipars.c

   1 /* packet-ipars.c
   2  * Routines for IPARS/ALC (International Passenger Airline Reservation System/Airline Link Control) WAN protocol dissection
   3  * Copyright 2007, Fulko Hew, SITA INC Canada, Inc.
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  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.
  15  *
  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.
  20  *
  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.
  24  */
  25
  26 /* Use tabstops = 4 */
  27
  28 /* NOTE:        This should be rewritten to be more in line with how packet-uts.c is
  29  *                      written so that there are filterable fields available for IPARS too.
  30  */
  31
  32 #ifdef HAVE_CONFIG_H
  33 # include "config.h"
  34 #endif
  35
  36 #include <glib.h>
  37 #include <epan/packet.h>
  38 #include <epan/emem.h>
  39
  40 static int              proto_ipars             = -1;
  41 static guint8   ipars_eomtype   = -1;
  42 static gint             ett_ipars               = -1;
  43
  44 #define S1              (0x00)
  45 #define S2              (0x20)
  46 #define GA              (0x03)
  47 #define EOMpb   (0x10)
  48 #define EOMc    (0x11)
  49 #define EOMu    (0x12)
  50 #define EOMi    (0x13)
  51
  52 #define MAX_EOM_MSG_SIZE        (16)                    /* max size of an EOMx indicator string */
  53
  54 static void
  55 dissect_ipars(tvbuff_t *tvb, packet_info *pinfo _U_ , proto_tree *tree)
  56 {
  57         proto_tree  *ipars_tree = NULL;
  58         proto_item  *ti;
  59         int                     bytes;
  60         guint8          ia = 0, ta = 0, cmd = 0, la = 0;
  61         tvbuff_t        *next_tvb;
  62         int                     offset = 0;
  63         gchar           *eom_msg;
  64
  65         eom_msg = ep_alloc(MAX_EOM_MSG_SIZE);
  66         eom_msg[0] = 0;
  67
  68         if (check_col(pinfo->cinfo, COL_INFO))
  69                 col_clear(pinfo->cinfo, COL_INFO);
  70
  71         if (check_col(pinfo->cinfo, COL_PROTOCOL))                                                                                              /* set the protocol column on summary display */
  72                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "IPARS");
  73
  74         if (tvb_length_remaining(tvb, 0) >= 2 ) {
  75                 ia = tvb_get_guint8(tvb, 0) & 0x3f;
  76                 ta = tvb_get_guint8(tvb, 1) & 0x3f;
  77                 if (ia == S1 && ta == S2) {                                                                                                                     /* if the first two bytes are S1/S2 skip over them */
  78                         offset = 2;
  79                 }
  80         }
  81         if (tvb_length_remaining(tvb, offset) >= 1) ia = tvb_get_guint8(tvb, offset + 0);
  82         if (tvb_length_remaining(tvb, offset) >= 2) ta = tvb_get_guint8(tvb, offset + 1);
  83
  84         if (ia == 0x83 || ia == 0x43 || ia == GA) {                                                                                             /* if its an FPGA or 'corresponsdance code' 'go ahead'... */
  85                 if (tvb_length_remaining(tvb, offset) > 2) {                                                                            /* if the msg is long, it must have been a 'poll' */
  86                         if (check_col(pinfo->cinfo, COL_INFO))
  87                                 col_add_fstr(pinfo->cinfo, COL_INFO, "Poll IA: %2.2X", ta);
  88                 } else {                                                                                                                                                        /* if its short, then it was a 'no traffic' response */
  89                         if (tvb_length_remaining(tvb, offset) >= 2 ) {
  90                                 if (check_col(pinfo->cinfo, COL_INFO))
  91                                         col_add_fstr(pinfo->cinfo, COL_INFO, "GoAhead NextIA (0x%2.2X)", ta);
  92                         } else {
  93                                 if (check_col(pinfo->cinfo, COL_INFO))
  94                                         col_add_str(pinfo->cinfo, COL_INFO, "GoAhead NextIA");
  95                         }
  96                 }
  97         } else {                                                                                                                                                /* if its not a 'go ahead'... it must be some kind of data message */
  98                 ia &= 0x3f;
  99                 ta &= 0x3f;
 100                 if (ta == 0x20) {
 101                         if (check_col(pinfo->cinfo, COL_INFO))
 102                                 col_add_fstr(pinfo->cinfo, COL_INFO, "Reset IA: %2.2X", ia);                                            /* the TA character was the 'reset' command */
 103                 }
 104                 if (tvb_length_remaining(tvb, offset) >= 3) cmd = tvb_get_guint8(tvb, offset + 2) & 0x3f;       /* get the first two bytes of the data message */
 105                 if (tvb_length_remaining(tvb, offset) >= 4) la  = tvb_get_guint8(tvb, offset + 3) & 0x3f;
 106                 if (cmd == 0x1f && la == 0x38) {
 107                         if (check_col(pinfo->cinfo, COL_INFO))
 108                                 col_add_fstr(pinfo->cinfo, COL_INFO, "Please Resend - IA: %2.2X TA: %2.2X", ia, ta);                            /* light the resend indicator */
 109                 } else if (cmd == 0x2a && la == 0x05) {
 110                         if (check_col(pinfo->cinfo, COL_INFO))
 111                                 col_add_fstr(pinfo->cinfo, COL_INFO, "Unsolicited Msg Indicator - IA: %2.2X TA: %2.2X", ia, ta);        /* light the unsolicited msg indicator */
 112                 } else {
 113                         if (check_col(pinfo->cinfo, COL_INFO))
 114                                 col_add_fstr(pinfo->cinfo, COL_INFO, "Data Msg - IA: %2.2X TA: %2.2X", ia, ta);                                         /* it was a data message (display or printer */
 115                 }
 116         }
 117
 118         if (tree) {
 119                 bytes = tvb_length_remaining(tvb, 0);
 120                 if (bytes > 0) {
 121                         ia = tvb_get_guint8(tvb, 0) & 0x3f;
 122
 123                         ti = proto_tree_add_protocol_format(tree, proto_ipars, tvb, 0, -1, "Ipars");
 124                         ipars_tree = proto_item_add_subtree(ti, ett_ipars);
 125
 126                         if (ia == 0x03) {
 127                                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 0, 1, "GoAhead Next IA");
 128                                 if (check_col(pinfo->cinfo, COL_INFO))
 129                                         col_add_str(pinfo->cinfo, COL_INFO, "GoAhead");
 130                                 return;
 131                         } else if (ia != S1) {
 132                                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb,
 133                                         0,
 134                                         bytes, "Unknown format - Data (%d byte%s)", bytes,
 135                                         plurality(bytes, "", "s"));
 136                                 return;
 137                         }
 138                         proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 0, 1, "S1");
 139                         ia = tvb_get_guint8(tvb, 1) & 0x3f;
 140                         if (ia != S2) {
 141                                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb,
 142                                         0,
 143                                         bytes, "Unknown format - Data (%d byte%s)", bytes,
 144                                         plurality(bytes, "", "s"));
 145                                 return;
 146                         }
 147                         proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 1, 1, "S2");
 148                         ia = tvb_get_guint8(tvb, 2) & 0x3f;
 149                         if (ia == GA) {
 150                                 ia = tvb_get_guint8(tvb, 3) & 0x3f;
 151                                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 2, 2, "GoAhead IA: %2.2X", ia);
 152                                 ipars_eomtype = tvb_get_guint8(tvb, 4) & 0x3f;
 153                                 switch (ipars_eomtype) {
 154                                         case EOMc:      g_snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMc");                                                          break;
 155                                         case EOMi:      g_snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMi");                                                          break;
 156                                         case EOMu:      g_snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMu");                                                          break;
 157                                         case EOMpb:     g_snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMpb");                                                         break;
 158                                         default:        g_snprintf(eom_msg, MAX_EOM_MSG_SIZE, "Unknown EOM type (0x%2.2X)", ia);        break;
 159                                 }
 160                                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 4, 1, "%s", eom_msg);
 161                                 ia = tvb_get_guint8(tvb, 5) & 0x3f;
 162                                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 5, 1, "Good BCC");
 163                         } else {
 164                                 next_tvb = tvb_new_subset(tvb, 3, -1, -1);
 165                                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, next_tvb,
 166                                         0,
 167                                         bytes, "Data (%d byte%s)", bytes,
 168                                         plurality(bytes, "", "s"));
 169                                 /* tvb_free(next_tvb);  */                              /* having this uncommented seems to cause a segfault (Fulko Hew, Nov 6/07) */
 170                                 return;
 171
 172                         }
 173                 }
 174         }
 175 }
 176
 177 void
 178 proto_register_ipars(void)
 179 {
 180         static gint *ett[] = {
 181                 &ett_ipars,
 182         };
 183
 184         proto_ipars = proto_register_protocol("International Passenger Airline Reservation System ", "IPARS", "ipars");         /* name, short name, abbrev */
 185         proto_register_subtree_array(ett, array_length(ett));
 186
 187         register_dissector("ipars", dissect_ipars, proto_ipars);
 188 }