plugins/epan/ethercat/packet-ethercat-frame.c

   1 /* packet-ethercat-frame.c
   2  * Routines for ethercat packet disassembly
   3  *
   4  * Copyright (c) 2007 by Beckhoff Automation GmbH
   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 files */
  14
  15 #include "config.h"
  16
  17 #include <epan/packet.h>
  18 #include <epan/etypes.h>
  19
  20 #include "packet-ethercat-frame.h"
  21
  22 void proto_register_ethercat_frame(void);
  23 void proto_reg_handoff_ethercat_frame(void);
  24
  25 /* Define the Ethercat frame proto */
  26 static int proto_ethercat_frame;
  27
  28 static dissector_table_t ethercat_frame_dissector_table;
  29
  30 static dissector_handle_t ethercat_frame_handle;
  31
  32 /* Define the tree for the EtherCAT frame */
  33 static int ett_ethercat_frame;
  34 static int hf_ethercat_frame_length;
  35 static int hf_ethercat_frame_reserved;
  36 static int hf_ethercat_frame_type;
  37
  38 static const value_string EthercatFrameTypes[] =
  39 {
  40    { 1, "EtherCAT command", },
  41    { 2, "ADS", },
  42    { 3, "RAW-IO", },
  43    { 4, "NV", },
  44    { 5, "Mailbox"},
  45    { 0,  NULL }
  46 };
  47
  48 static const value_string ethercat_frame_reserved_vals[] =
  49 {
  50    { 0, "Valid"},
  51    { 1, "Invalid (must be zero for conformance with the protocol specification)"},
  52    { 0, NULL}
  53 };
  54
  55 /* Ethercat Frame */
  56 static int dissect_ethercat_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  57 {
  58    tvbuff_t *next_tvb;
  59    proto_item *ti;
  60    proto_tree *ethercat_frame_tree;
  61    int offset = 0;
  62    EtherCATFrameParserHDR hdr;
  63
  64    col_set_str(pinfo->cinfo, COL_PROTOCOL, "ECATF");
  65
  66    col_clear(pinfo->cinfo, COL_INFO);
  67
  68    if (tree)
  69    {
  70       ti = proto_tree_add_item(tree, proto_ethercat_frame, tvb, offset, EtherCATFrameParserHDR_Len, ENC_NA);
  71       ethercat_frame_tree = proto_item_add_subtree(ti, ett_ethercat_frame);
  72
  73       proto_tree_add_item(ethercat_frame_tree, hf_ethercat_frame_length, tvb, offset, EtherCATFrameParserHDR_Len, ENC_LITTLE_ENDIAN);
  74       proto_tree_add_item(ethercat_frame_tree, hf_ethercat_frame_reserved, tvb, offset, EtherCATFrameParserHDR_Len, ENC_LITTLE_ENDIAN);
  75       proto_tree_add_item(ethercat_frame_tree, hf_ethercat_frame_type, tvb, offset, EtherCATFrameParserHDR_Len, ENC_LITTLE_ENDIAN);
  76    }
  77    hdr.hdr = tvb_get_letohs(tvb, offset);
  78    offset = EtherCATFrameParserHDR_Len;
  79
  80    /* The EtherCAT frame header has now been processed, allow sub dissectors to
  81       handle the rest of the PDU. */
  82    next_tvb = tvb_new_subset_remaining (tvb, offset);
  83
  84    if (!dissector_try_uint(ethercat_frame_dissector_table, hdr.v.protocol,
  85        next_tvb, pinfo, tree))
  86    {
  87       col_add_fstr (pinfo->cinfo, COL_PROTOCOL, "0x%04x", hdr.v.protocol);
  88       /* No sub dissector wanted to handle this payload, decode it as general
  89       data instead. */
  90       call_data_dissector(next_tvb, pinfo, tree);
  91    }
  92    return tvb_captured_length(tvb);
  93 }
  94
  95 void proto_register_ethercat_frame(void)
  96 {
  97    static hf_register_info hf[] =
  98       {
  99          { &hf_ethercat_frame_length,
 100            { "Length", "ecatf.length",
 101              FT_UINT16, BASE_HEX, NULL, 0x07FF,
 102              NULL, HFILL }
 103          },
 104
 105          { &hf_ethercat_frame_reserved,
 106            { "Reserved", "ecatf.reserved",
 107              FT_UINT16, BASE_HEX, VALS(ethercat_frame_reserved_vals), 0x0800,
 108              NULL, HFILL}
 109          },
 110
 111          { &hf_ethercat_frame_type,
 112            { "Type", "ecatf.type",
 113              FT_UINT16, BASE_HEX, VALS(EthercatFrameTypes), 0xF000,
 114              "E88A4 Types", HFILL }
 115          }
 116       };
 117
 118    static int *ett[] =
 119       {
 120          &ett_ethercat_frame
 121       };
 122
 123    proto_ethercat_frame = proto_register_protocol("EtherCAT frame header", "ETHERCAT", "ecatf");
 124    proto_register_field_array(proto_ethercat_frame,hf,array_length(hf));
 125    proto_register_subtree_array(ett, array_length(ett));
 126
 127    ethercat_frame_handle = register_dissector("ecatf", dissect_ethercat_frame, proto_ethercat_frame);
 128
 129    /* Define a handle (ecatf.type) for sub dissectors that want to dissect
 130       the Ethercat frame ether type (E88A4) payload. */
 131    ethercat_frame_dissector_table = register_dissector_table("ecatf.type", "EtherCAT frame type",
 132                                                              proto_ethercat_frame, FT_UINT8, BASE_DEC);
 133 }
 134
 135 void proto_reg_handoff_ethercat_frame(void)
 136 {
 137    dissector_add_uint("ethertype", ETHERTYPE_ECATF, ethercat_frame_handle);
 138    dissector_add_uint_with_preference("udp.port", ETHERTYPE_ECATF, ethercat_frame_handle);
 139    dissector_add_uint_with_preference("tcp.port", ETHERTYPE_ECATF, ethercat_frame_handle);
 140 }
 141
 142 /*
 143  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 144  *
 145  * Local Variables:
 146  * c-basic-offset: 3
 147  * tab-width: 8
 148  * indent-tabs-mode: nil
 149  * End:
 150  *
 151  * ex: set shiftwidth=3 tabstop=8 expandtab:
 152  * :indentSize=3:tabSize=8:noTabs=true:
 153  */