epan/dissectors/packet-etherip.c

   1 /*
   2  * Copyright (c) 2003 Markus Friedl.  All rights reserved.
   3  *
   4  * SPDX-License-Identifier: BSD-2-Clause
   5  */
   6
   7 #include "config.h"
   8
   9 #include <epan/packet.h>
  10 #include <epan/ipproto.h>
  11 #include <epan/expert.h>
  12
  13 void proto_register_etherip(void);
  14 void proto_reg_handoff_etherip(void);
  15
  16 static int proto_etherip;
  17 static int hf_etherip_ver;
  18 static int hf_etherip_reserved;
  19
  20 static int ett_etherip;
  21
  22 static expert_field ei_etherip_ver_3;
  23 static expert_field ei_etherip_reserved_0;
  24
  25 static dissector_handle_t eth_withoutfcs_handle;
  26 static dissector_handle_t etherip_handle;
  27
  28 /*
  29  * RFC 3378: EtherIP: Tunneling Ethernet Frames in IP Datagrams
  30  *
  31  *      Bits 0-3:  Protocol version
  32  *      Bits 4-15: Reserved for future use
  33  */
  34
  35 #define ETHERIP_VERS_MASK    0xF000
  36 #define ETHERIP_RESERVE_MASK 0x0FFF
  37
  38
  39 static int
  40 dissect_etherip(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  41 {
  42   tvbuff_t *next_tvb;
  43   proto_tree *etherip_tree;
  44   proto_item *ti;
  45   uint16_t field, version;
  46
  47   col_set_str(pinfo->cinfo, COL_PROTOCOL, "ETHERIP");
  48
  49   field = tvb_get_ntohs(tvb, 0);
  50   version = (field & ETHERIP_VERS_MASK) >> 12;
  51
  52   if (tree) {
  53     ti = proto_tree_add_protocol_format(tree, proto_etherip, tvb, 0,
  54              2,
  55              "EtherIP, Version %d",
  56              version
  57              );
  58     etherip_tree = proto_item_add_subtree(ti, ett_etherip);
  59
  60     ti = proto_tree_add_item(etherip_tree, hf_etherip_ver, tvb,
  61              0, 2, ENC_BIG_ENDIAN);
  62     if (version != 3) {
  63       expert_add_info(pinfo, ti, &ei_etherip_ver_3);
  64     }
  65
  66     ti = proto_tree_add_item(etherip_tree, hf_etherip_reserved, tvb,
  67              0, 2, ENC_BIG_ENDIAN);
  68     if ((field & ETHERIP_RESERVE_MASK) != 0) {
  69       expert_add_info(pinfo, ti, &ei_etherip_reserved_0);
  70     }
  71   }
  72
  73   /* Set the tvbuff for the payload after the header */
  74   next_tvb = tvb_new_subset_remaining(tvb, 2);
  75
  76   call_dissector(eth_withoutfcs_handle, next_tvb, pinfo, tree);
  77   return tvb_captured_length(tvb);
  78 }
  79
  80 void
  81 proto_register_etherip(void)
  82 {
  83   static hf_register_info hf_etherip[] = {
  84     { &hf_etherip_ver,
  85       { "Version", "etherip.ver", FT_UINT16, BASE_DEC, NULL, ETHERIP_VERS_MASK,
  86         NULL, HFILL }},
  87     { &hf_etherip_reserved,
  88       { "Reserved", "etherip.reserved", FT_UINT16, BASE_HEX, NULL, ETHERIP_RESERVE_MASK,
  89         "Reserved (must be 0)", HFILL }},
  90   };
  91
  92   static int *ett[] = {
  93     &ett_etherip,
  94   };
  95
  96   static ei_register_info ei[] = {
  97      { &ei_etherip_ver_3, { "etherip.ver.not3", PI_PROTOCOL, PI_WARN, "Version must be 3", EXPFILL }},
  98      { &ei_etherip_reserved_0, { "etherip.reserved.not0", PI_PROTOCOL, PI_WARN, "Reserved field must be 0", EXPFILL }},
  99   };
 100
 101   expert_module_t* expert_etherip;
 102
 103   proto_etherip = proto_register_protocol("Ethernet over IP",
 104                                           "ETHERIP", "etherip");
 105   proto_register_field_array(proto_etherip, hf_etherip, array_length(hf_etherip));
 106   proto_register_subtree_array(ett, array_length(ett));
 107   expert_etherip = expert_register_protocol(proto_etherip);
 108   expert_register_field_array(expert_etherip, ei, array_length(ei));
 109
 110   etherip_handle = register_dissector("etherip", dissect_etherip, proto_etherip);
 111 }
 112
 113 void
 114 proto_reg_handoff_etherip(void)
 115 {
 116   eth_withoutfcs_handle = find_dissector_add_dependency("eth_withoutfcs", proto_etherip);
 117   dissector_add_uint("ip.proto", IP_PROTO_ETHERIP, etherip_handle);
 118 }
 119
 120 /*
 121  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 122  *
 123  * Local Variables:
 124  * c-basic-offset: 2
 125  * tab-width: 8
 126  * indent-tabs-mode: nil
 127  * End:
 128  *
 129  * ex: set shiftwidth=2 tabstop=8 expandtab:
 130  * :indentSize=2:tabSize=8:noTabs=true:
 131  */