epan/dissectors/packet-qllc.c

   1 /* packet-qllc.c
   2  * Routines for QLLC protocol - Qualified? LLC
   3  * Gilbert Ramirez <gram@alumni.rice.edu>
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 2001 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 #include "config.h"
  27
  28 #include <glib.h>
  29 #include <epan/packet.h>
  30
  31 static int proto_qllc = -1;
  32 static int hf_qllc_address = -1;
  33 static int hf_qllc_control = -1;
  34
  35 static gint ett_qllc = -1;
  36
  37 static dissector_handle_t sna_handle;
  38
  39 #define QSM                 0x93
  40 #define QDISC               0x53
  41 #define QXID                0xbf
  42 #define QTEST               0xf3
  43 #define QRR                 0xf1
  44 #define QRD                 0x53
  45 #define QUA                 0x73
  46 #define QDM                 0x1f
  47 #define QFRMR               0x97
  48 #define QUI                 0x03
  49 #define QUI_NO_REPLY        0x13
  50 #define QSIM                0x17
  51
  52 #define QRD_QDISC_VALUE     0x53
  53 #define QDISC_TEXT          "QDISC"
  54 #define QRD_TEXT            "QRD"
  55
  56 /* Control Field */
  57 static const value_string qllc_control_vals[] = {
  58     { QUI,          "QUI" },
  59     { QUI_NO_REPLY, "QUI - reply required" },
  60     { QSIM,         "QSIM" },
  61     { QDM,          "QDM" },
  62     { QUA,          "QUA" },
  63     { QSM,          "QSM" },
  64     { QFRMR,        "QFRMR" },
  65     { QXID,         "QXID" },
  66     { QRR,          "QRR" },
  67     { QTEST,        "QTEST" },
  68     { QDISC,        QDISC_TEXT },
  69     { QRD,          QRD_TEXT },
  70     { 0x00, NULL },
  71 };
  72
  73
  74 static int
  75 dissect_qllc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
  76 {
  77     proto_tree  *qllc_tree;
  78     proto_item  *qllc_ti;
  79     gboolean    *q_bit_set = (gboolean *)data;
  80     guint8      addr, ctrl;
  81     gboolean    command = FALSE;
  82
  83     /*
  84      * If the Q bit isn't set, this is just SNA data.
  85      */
  86     if (!(*q_bit_set)) {
  87         call_dissector(sna_handle, tvb, pinfo, tree);
  88         return tvb_length(tvb);
  89     }
  90
  91     /* Summary information */
  92     col_set_str(pinfo->cinfo, COL_PROTOCOL, "QLLC");
  93     col_clear(pinfo->cinfo, COL_INFO);
  94
  95     qllc_ti = proto_tree_add_item(tree, proto_qllc, tvb, 0, -1, ENC_NA);
  96     qllc_tree = proto_item_add_subtree(qllc_ti, ett_qllc);
  97
  98     /* Get the address; we need it to determine if this is a
  99      * COMMAND or a RESPONSE */
 100     addr = tvb_get_guint8(tvb, 0);
 101         proto_tree_add_item(qllc_tree, hf_qllc_address, tvb, 0, 1, ENC_BIG_ENDIAN);
 102
 103     /* The address field equals X'FF' in commands (except QRR)
 104      * and anything in responses. */
 105     ctrl = tvb_get_guint8(tvb, 1);
 106     if (ctrl != QRR && addr == 0xff) {
 107         command = TRUE;
 108     }
 109
 110
 111     /* Disambiguate QRD_QDISC_VALUE, based on whether this packet is
 112      * a COMMAND or RESPONSE. */
 113     if (ctrl == QRD_QDISC_VALUE) {
 114         if (command) {
 115         col_set_str(pinfo->cinfo, COL_INFO, QDISC_TEXT);
 116             if (tree) {
 117                 proto_tree_add_text(qllc_tree, tvb,
 118                         1, 1, "Control Field: %s (0x%02x)", QDISC_TEXT, ctrl);
 119             }
 120         }
 121         else {
 122         col_set_str(pinfo->cinfo, COL_INFO, QRD_TEXT);
 123             if (tree) {
 124                 proto_tree_add_text(qllc_tree, tvb,
 125                         1, 1, "Control Field: %s (0x%02x)", QRD_TEXT, ctrl);
 126             }
 127         }
 128
 129         /* Add the field for filtering purposes */
 130         if (tree) {
 131             proto_item *hidden_item;
 132             hidden_item = proto_tree_add_uint(qllc_tree, hf_qllc_control, tvb,
 133                     1, 1, ctrl);
 134             PROTO_ITEM_SET_HIDDEN(hidden_item);
 135         }
 136     }
 137     else {
 138         /* Non-ambiguous control field value */
 139         col_add_str(pinfo->cinfo, COL_INFO,
 140                     val_to_str(ctrl, qllc_control_vals,
 141                         "Control Field: 0x%02x (unknown)"));
 142
 143         proto_tree_add_uint(qllc_tree, hf_qllc_control, tvb,
 144                     1, 1, ctrl);
 145     }
 146
 147     /* Do we have an I field ? */
 148     /* XXX - I field exists for QUI too, but only for subarea nodes.
 149      * Need to test for this. */
 150     if (ctrl == QXID || ctrl == QTEST || ctrl == QFRMR) {
 151         /* yes */
 152     }
 153
 154     return tvb_length(tvb);
 155 }
 156
 157 void
 158 proto_register_qllc(void)
 159 {
 160         static hf_register_info hf[] = {
 161             { &hf_qllc_address,
 162                 { "Address Field",      "qllc.address", FT_UINT8, BASE_HEX, NULL, 0x0,
 163                         NULL, HFILL }},
 164
 165                 { &hf_qllc_control,
 166                 { "Control Field",      "qllc.control", FT_UINT8, BASE_HEX,
 167                   VALS(qllc_control_vals), 0x0, NULL, HFILL }},
 168         };
 169
 170         static gint *ett[] = {
 171                 &ett_qllc,
 172         };
 173
 174         proto_qllc = proto_register_protocol("Qualified Logical Link Control", "QLLC", "qllc");
 175         proto_register_field_array(proto_qllc, hf, array_length(hf));
 176         proto_register_subtree_array(ett, array_length(ett));
 177         new_register_dissector("qllc", dissect_qllc, proto_qllc);
 178 }
 179
 180 void
 181 proto_reg_handoff_qllc(void)
 182 {
 183         sna_handle = find_dissector("sna");
 184 }