epan/dissectors/packet-nwmtp.c

   1 /* packet-nwmtp.c
   2  * Routines for NexusWare MTP3 over UDP transport
   3  * Copyright 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
   4  * Copyright 2010 by On-Waves
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * SPDX-License-Identifier: GPL-2.0-or-later
  11  */
  12
  13 #include "config.h"
  14
  15 #include <epan/packet.h>
  16
  17 void proto_register_mwmtp(void);
  18 void proto_reg_handoff_nwmtp(void);
  19
  20 static dissector_handle_t mtp_handle;
  21 static int proto_nwmtp;
  22
  23 static int hf_nwmtp_transp_type;
  24 static int hf_nwmtp_user_context;
  25 static int hf_nwmtp_data_type;
  26 static int hf_nwmtp_data_index;
  27 static int hf_nwmtp_data_length;
  28
  29 /* subtree pointer */
  30 static int ett_mwmtp;
  31
  32 static dissector_handle_t nwmtp_handle;
  33
  34 static const value_string nwmtp_transport_type_vals[] = {
  35         { 2,        "UDP" },
  36         { 3,        "TCP" },
  37         { 0,        NULL  },
  38 };
  39
  40 static const value_string nwmtp_data_type_vals[] = {
  41         { 0,        "MSU Prio 0" },
  42         { 1,        "MSU Prio 1" },
  43         { 2,        "MSU Prio 2" },
  44         { 3,        "MSU Prio 3" },
  45         {16,        "Retrieved MSU Prio 0" },
  46         {17,        "Retrieved MSU Prio 0" },
  47         {18,        "Retrieved MSU Prio 0" },
  48         {32,        "Retrieval complete"   },
  49         {33,        "Retrieval impossible" },
  50         {34,        "Link in service"      },
  51         {35,        "Link out of service"  },
  52         { 0,        NULL },
  53 };
  54
  55 static int dissect_nwmtp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  56 {
  57         int offset = 0;
  58
  59         col_set_str(pinfo->cinfo, COL_PROTOCOL, "NW MTP");
  60         col_clear(pinfo->cinfo, COL_INFO);
  61
  62         while (tvb_reported_length_remaining(tvb, offset) > 0) {
  63                 const char *type;
  64                 proto_item *ti;
  65                 proto_item *nwmtp_tree;
  66                 uint32_t len;
  67                 tvbuff_t *next_tvb;
  68
  69                 /* update the info column */
  70                 type = val_to_str_const(tvb_get_uint8(tvb, offset + 1),
  71                                         nwmtp_data_type_vals, "Unknown");
  72                 col_set_str(pinfo->cinfo, COL_INFO, type);
  73
  74                 len = tvb_get_ntohl(tvb, offset + 8);
  75
  76                 if (tree) {
  77                         ti = proto_tree_add_protocol_format(tree, proto_nwmtp,
  78                                         tvb, offset, len + 12,
  79                                         "NexusWare C7 UDP Protocol");
  80
  81                         nwmtp_tree = proto_item_add_subtree(ti, ett_mwmtp);
  82                         proto_tree_add_item(nwmtp_tree, hf_nwmtp_transp_type,
  83                                             tvb, offset, 1, ENC_BIG_ENDIAN);
  84                         proto_tree_add_item(nwmtp_tree, hf_nwmtp_data_type,
  85                                             tvb, offset + 1, 1, ENC_BIG_ENDIAN);
  86                         proto_tree_add_item(nwmtp_tree, hf_nwmtp_data_index,
  87                                             tvb, offset + 2, 2, ENC_BIG_ENDIAN);
  88                         proto_tree_add_item(nwmtp_tree, hf_nwmtp_user_context,
  89                                             tvb, offset + 4, 4, ENC_BIG_ENDIAN);
  90                         proto_tree_add_item(nwmtp_tree, hf_nwmtp_data_length,
  91                                             tvb, offset + 8, 4, ENC_BIG_ENDIAN);
  92                 }
  93
  94                 next_tvb = tvb_new_subset_length(tvb, offset + 12, len);
  95                 if (tvb_reported_length(next_tvb) > 0)
  96                         call_dissector(mtp_handle, next_tvb, pinfo, tree);
  97                 /* Check for overflows, which probably can't happen, but better
  98                  * safe than sorry. See
  99                  * https://gitlab.com/wireshark/wireshark/-/issues/8169
 100                  */
 101                 DISSECTOR_ASSERT(len < UINT32_MAX - 11);
 102                 DISSECTOR_ASSERT((uint64_t)offset + len + 12 < INT_MAX);
 103                 offset += len + 12;
 104         }
 105
 106         return tvb_captured_length(tvb);
 107 }
 108
 109 void proto_register_mwmtp(void)
 110 {
 111         static hf_register_info hf[] = {
 112                 {&hf_nwmtp_transp_type,
 113                  {"Transport Type", "nwmtp.transp_type",
 114                   FT_UINT8, BASE_DEC, VALS(nwmtp_transport_type_vals), 0x0,
 115                   "The Transport Type", HFILL}
 116                 },
 117                 {&hf_nwmtp_data_type,
 118                  {"Data Type", "nwmtp.data_type",
 119                   FT_UINT8, BASE_DEC, VALS(nwmtp_data_type_vals), 0x0,
 120                   "The Data Type", HFILL}
 121                 },
 122                 {&hf_nwmtp_data_index,
 123                  {"Link Index", "nwmtp.link_index",
 124                   FT_UINT16, BASE_DEC, NULL, 0x0,
 125                   NULL, HFILL}
 126                 },
 127                 {&hf_nwmtp_user_context,
 128                  {"User Context", "nwmtp.user_context",
 129                   FT_UINT32, BASE_DEC, NULL, 0x0,
 130                   "Use Context", HFILL}
 131                 },
 132                 {&hf_nwmtp_data_length,
 133                  {"Length", "nwmtp.data_length",
 134                   FT_UINT32, BASE_DEC, NULL, 0x0,
 135                   "Data Length", HFILL}
 136                 },
 137         };
 138
 139         static int *ett[] = {
 140                 &ett_mwmtp,
 141         };
 142
 143         proto_nwmtp =
 144              proto_register_protocol("NexusWare C7 MTP", "MTP over NW UDP", "nw_mtp");
 145
 146         proto_register_field_array(proto_nwmtp, hf, array_length(hf));
 147         proto_register_subtree_array(ett, array_length(ett));
 148
 149         nwmtp_handle = register_dissector("nw_mtp", dissect_nwmtp, proto_nwmtp);
 150 }
 151
 152 void proto_reg_handoff_nwmtp(void)
 153 {
 154         dissector_add_for_decode_as_with_preference("udp.port", nwmtp_handle);
 155         mtp_handle = find_dissector_add_dependency("mtp3", proto_nwmtp);
 156 }
 157
 158 /*
 159  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 160  *
 161  * Local variables:
 162  * c-basic-offset: 8
 163  * tab-width: 8
 164  * indent-tabs-mode: t
 165  * End:
 166  *
 167  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 168  * :indentSize=8:tabSize=8:noTabs=false:
 169  */