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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24  */
  25
  26 /* NOTE:        This should be rewritten to be more in line with how packet-uts.c is
  27  *                      written so that there are filterable fields available for IPARS too.
  28  */
  29
  30 #include "config.h"
  31
  32 #include <glib.h>
  33 #include <epan/packet.h>
  34 #include <epan/wmem/wmem.h>
  35
  36 static int      proto_ipars     = -1;
  37 static guint8   ipars_eomtype   = G_MAXUINT8;
  38 static gint     ett_ipars       = -1;
  39
  40 #define S1      (0x00)
  41 #define S2      (0x20)
  42 #define GA      (0x03)
  43 #define EOMpb   (0x10)
  44 #define EOMc    (0x11)
  45 #define EOMu    (0x12)
  46 #define EOMi    (0x13)
  47
  48 #define MAX_EOM_MSG_SIZE    (16)            /* max size of an EOMx indicator string */
  49
  50 static void
  51 dissect_ipars(tvbuff_t *tvb, packet_info *pinfo _U_ , proto_tree *tree)
  52 {
  53     proto_tree  *ipars_tree = NULL;
  54     proto_item  *ti;
  55     int         bytes;
  56     guint8      ia = 0, ta = 0, cmd = 0, la = 0;
  57     tvbuff_t    *next_tvb;
  58     int         offset = 0;
  59     gchar       *eom_msg;
  60
  61     eom_msg = (gchar *)wmem_alloc(wmem_packet_scope(), MAX_EOM_MSG_SIZE);
  62     eom_msg[0] = 0;
  63
  64     col_clear(pinfo->cinfo, COL_INFO);
  65
  66     col_set_str(pinfo->cinfo, COL_PROTOCOL, "IPARS");
  67
  68     if (tvb_length_remaining(tvb, 0) >= 2 ) {
  69         ia = tvb_get_guint8(tvb, 0) & 0x3f;
  70         ta = tvb_get_guint8(tvb, 1) & 0x3f;
  71         if (ia == S1 && ta == S2) { /* if the first two bytes are S1/S2 skip over them */
  72             offset = 2;
  73         }
  74     }
  75     if (tvb_length_remaining(tvb, offset) >= 1) ia = tvb_get_guint8(tvb, offset + 0);
  76     if (tvb_length_remaining(tvb, offset) >= 2) ta = tvb_get_guint8(tvb, offset + 1);
  77
  78     if (ia == 0x83 || ia == 0x43 || ia == GA) { /* if it's an FPGA or 'corresponsdance code' 'go ahead'... */
  79         if (tvb_length_remaining(tvb, offset) > 2) { /* if the msg is long, it must have been a 'poll' */
  80             col_add_fstr(pinfo->cinfo, COL_INFO, "Poll IA: %2.2X", ta);
  81         } else { /* if it's short, then it was a 'no traffic' response */
  82             if (tvb_length_remaining(tvb, offset) >= 2 ) {
  83                 col_add_fstr(pinfo->cinfo, COL_INFO, "GoAhead NextIA (0x%2.2X)", ta);
  84             } else {
  85                 col_set_str(pinfo->cinfo, COL_INFO, "GoAhead NextIA");
  86             }
  87         }
  88     } else { /* if it's not a 'go ahead'... it must be some kind of data message */
  89         ia &= 0x3f;
  90         ta &= 0x3f;
  91         if (ta == 0x20) {
  92             col_add_fstr(pinfo->cinfo, COL_INFO, "Reset IA: %2.2X", ia); /* the TA character was the 'reset' command */
  93         }
  94         if (tvb_length_remaining(tvb, offset) >= 3) cmd = tvb_get_guint8(tvb, offset + 2) & 0x3f;   /* get the first two bytes of the data message */
  95         if (tvb_length_remaining(tvb, offset) >= 4) la  = tvb_get_guint8(tvb, offset + 3) & 0x3f;
  96         if (cmd == 0x1f && la == 0x38) {
  97             col_add_fstr(pinfo->cinfo, COL_INFO, "Please Resend - IA: %2.2X TA: %2.2X", ia, ta); /* light the resend indicator */
  98         } else if (cmd == 0x2a && la == 0x05) {
  99             col_add_fstr(pinfo->cinfo, COL_INFO, "Unsolicited Msg Indicator - IA: %2.2X TA: %2.2X", ia, ta);    /* light the unsolicited msg indicator */
 100         } else {
 101             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 */
 102         }
 103     }
 104
 105     if (tree) {
 106         bytes = tvb_length_remaining(tvb, 0);
 107         if (bytes > 0) {
 108             ia = tvb_get_guint8(tvb, 0) & 0x3f;
 109
 110             ti = proto_tree_add_protocol_format(tree, proto_ipars, tvb, 0, -1, "Ipars");
 111             ipars_tree = proto_item_add_subtree(ti, ett_ipars);
 112
 113             if (ia == 0x03) {
 114                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 0, 1, "GoAhead Next IA");
 115                 col_set_str(pinfo->cinfo, COL_INFO, "GoAhead");
 116                 return;
 117             } else if (ia != S1) {
 118                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb,
 119                     0,
 120                     bytes, "Unknown format - Data (%d byte%s)", bytes,
 121                     plurality(bytes, "", "s"));
 122                 return;
 123             }
 124             proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 0, 1, "S1");
 125             ia = tvb_get_guint8(tvb, 1) & 0x3f;
 126             if (ia != S2) {
 127                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb,
 128                     0,
 129                     bytes, "Unknown format - Data (%d byte%s)", bytes,
 130                     plurality(bytes, "", "s"));
 131                 return;
 132             }
 133             proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 1, 1, "S2");
 134             ia = tvb_get_guint8(tvb, 2) & 0x3f;
 135             if (ia == GA) {
 136                 ia = tvb_get_guint8(tvb, 3) & 0x3f;
 137                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 2, 2, "GoAhead IA: %2.2X", ia);
 138                 ipars_eomtype = tvb_get_guint8(tvb, 4) & 0x3f;
 139                 switch (ipars_eomtype) {
 140                     case EOMc:  g_snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMc");                              break;
 141                     case EOMi:  g_snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMi");                              break;
 142                     case EOMu:  g_snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMu");                              break;
 143                     case EOMpb: g_snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMpb");                             break;
 144                     default:    g_snprintf(eom_msg, MAX_EOM_MSG_SIZE, "Unknown EOM type (0x%2.2X)", ia);    break;
 145                 }
 146                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 4, 1, "%s", eom_msg);
 147                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 5, 1, "Good BCC");
 148             } else {
 149                 next_tvb = tvb_new_subset_remaining(tvb, 3);
 150                 proto_tree_add_protocol_format(ipars_tree, proto_ipars, next_tvb,
 151                     0,
 152                     bytes, "Data (%d byte%s)", bytes,
 153                     plurality(bytes, "", "s"));
 154                 return;
 155
 156             }
 157         }
 158     }
 159 }
 160
 161 void
 162 proto_register_ipars(void)
 163 {
 164     static gint *ett[] = {
 165         &ett_ipars,
 166     };
 167
 168     proto_ipars = proto_register_protocol("International Passenger Airline Reservation System", "IPARS", "ipars");
 169     proto_register_subtree_array(ett, array_length(ett));
 170
 171     register_dissector("ipars", dissect_ipars, proto_ipars);
 172 }
 173
 174 /*
 175  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 176  *
 177  * Local variables:
 178  * c-basic-offset: 4
 179  * tab-width: 4
 180  * indent-tabs-mode: nil
 181  * End:
 182  *
 183  * vi: set shiftwidth=4 tabstop=4 expandtab:
 184  * :indentSize=4:tabSize=8:noTabs=true:
 185  */