epan/dissectors/packet-trill.c

   1 /* packet-trill.c
   2  * Routines for TRILL (TRansparent Interconnection of Lots of Links) dissection
   3  * Copyright 2010, David Bond <mokon@mokon.net>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 /*
  13  * See: RFC6325
  14  */
  15
  16 #include "config.h"
  17
  18 #include <epan/packet.h>
  19 #include <epan/etypes.h>
  20 #include <epan/tfs.h>
  21 #include <wsutil/array.h>
  22
  23 void proto_register_trill(void);
  24 void proto_reg_handoff_trill(void);
  25
  26 static dissector_handle_t trill_handle;
  27
  28 static int proto_trill;
  29 static int ett_trill;
  30
  31 static int hf_trill_version;
  32 static int hf_trill_reserved;
  33 static int hf_trill_multi_dst;
  34 static int hf_trill_op_len;
  35 static int hf_trill_hop_cnt;
  36 static int hf_trill_egress_nick;
  37 static int hf_trill_ingress_nick;
  38 /* TODO For now we will just add all the options into a byte field.
  39    Later this should be parsed out into a sub-tree with all the option
  40    details. */
  41 static int hf_trill_options;
  42
  43 static dissector_handle_t eth_dissector ;
  44
  45 #define TRILL_VERSION_MASK   0xC000
  46 #define TRILL_RESERVED_MASK  0x3000
  47 #define TRILL_MULTI_DST_MASK 0x0800
  48 #define TRILL_OP_LEN_MASK    0x07C0
  49 #define TRILL_HOP_CNT_MASK   0x003F
  50
  51 #define TRILL_PROTO_COL_NAME "TRILL"
  52 #define TRILL_PROTO_COL_INFO "TRILL Encapsulated Frame"
  53
  54 #define TRILL_MIN_FRAME_LENGTH     6
  55 #define TRILL_BIT_FIELDS_LEN       2
  56 #define TRILL_NICKNAME_LEN         2
  57 #define TRILL_OP_LENGTH_BYTE_UNITS 0x4
  58
  59 static const true_false_string multi_dst_strings = {
  60   "Multi-Destination TRILL Frame",
  61   "Known Unicast TRILL Frame"
  62 } ;
  63
  64 static const range_string version_strings[] = {
  65   { 0, 0, "RFC6325 Version" },
  66   { 1, 3, "Unallocated Version" },
  67   { 0, 0, NULL }
  68 } ;
  69
  70 static const range_string reserved_strings[] = {
  71   { 0, 0, "Legal Value" },
  72   { 1, 3, "Illegal Value" },
  73   { 0, 0, NULL }
  74 } ;
  75
  76 static const range_string nickname_strings[] = {
  77   { 0x0000, 0x0000, "Nickname Not Specified" },
  78   { 0x0001, 0xFFBF, "Valid Nickname" },
  79   { 0xFFC0, 0xFFC0, "Any RBridge" },
  80   { 0xFFC1, 0xFFC1, "OOMF" },
  81   { 0xFFC2, 0xFFFE, "Reserved for Future Specification" },
  82   { 0xFFFF, 0xFFFF, "Permanently Reserved" },
  83   { 0, 0, NULL }
  84 } ;
  85
  86 /* Trill Dissector */
  87 static int
  88 dissect_trill( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_ )
  89 {
  90   proto_item *ti ;
  91   proto_tree *trill_tree ;
  92   uint32_t    op_len ;
  93   tvbuff_t   *next_tvb ;
  94   int         offset = 0 ;
  95
  96   col_set_str( pinfo->cinfo, COL_PROTOCOL, TRILL_PROTO_COL_NAME ) ;
  97   col_set_str( pinfo->cinfo, COL_INFO, TRILL_PROTO_COL_INFO ) ;
  98
  99   op_len = tvb_get_bits( tvb, 5, 5, ENC_BIG_ENDIAN ) * TRILL_OP_LENGTH_BYTE_UNITS ;
 100   if (tree) {
 101     ti = proto_tree_add_item( tree, proto_trill, tvb, 0,
 102       TRILL_MIN_FRAME_LENGTH + op_len, ENC_NA ) ;
 103     trill_tree = proto_item_add_subtree( ti, ett_trill ) ;
 104
 105     /* Parse the bit fields, i.e. V, R, M, Op-Length, Hop Count. */
 106     proto_tree_add_item( trill_tree, hf_trill_version, tvb, offset,
 107       TRILL_BIT_FIELDS_LEN, ENC_BIG_ENDIAN ) ;
 108     proto_tree_add_item( trill_tree, hf_trill_reserved, tvb, offset,
 109       TRILL_BIT_FIELDS_LEN, ENC_BIG_ENDIAN ) ;
 110     proto_tree_add_item( trill_tree, hf_trill_multi_dst, tvb, offset,
 111       TRILL_BIT_FIELDS_LEN, ENC_BIG_ENDIAN ) ;
 112     proto_tree_add_item( trill_tree, hf_trill_op_len, tvb, offset,
 113       TRILL_BIT_FIELDS_LEN, ENC_BIG_ENDIAN ) ;
 114     proto_tree_add_item( trill_tree, hf_trill_hop_cnt, tvb, offset,
 115       TRILL_BIT_FIELDS_LEN, ENC_BIG_ENDIAN ) ;
 116
 117     /* Parse the egress nickname. */
 118     offset += TRILL_BIT_FIELDS_LEN ;
 119     proto_tree_add_item( trill_tree, hf_trill_egress_nick, tvb, offset,
 120       TRILL_NICKNAME_LEN, ENC_BIG_ENDIAN ) ;
 121
 122     /* Parse the ingress nickname. */
 123     offset += TRILL_NICKNAME_LEN  ;
 124     proto_tree_add_item( trill_tree, hf_trill_ingress_nick, tvb, offset,
 125       TRILL_NICKNAME_LEN , ENC_BIG_ENDIAN ) ;
 126
 127     /* Parse the options field. */
 128     offset += TRILL_NICKNAME_LEN  ;
 129     if( op_len != 0 ) {
 130       proto_tree_add_item( trill_tree, hf_trill_options, tvb,
 131         offset, op_len, ENC_NA ) ;
 132     }
 133   }
 134
 135   /* call the eth dissector */
 136   next_tvb = tvb_new_subset_remaining( tvb, TRILL_MIN_FRAME_LENGTH + op_len ) ;
 137   call_dissector( eth_dissector, next_tvb, pinfo, tree ) ;
 138
 139   return tvb_reported_length( tvb ) ;
 140 }
 141
 142 /* Register the protocol with Wireshark */
 143 void
 144 proto_register_trill(void)
 145 {
 146   static hf_register_info hf[] = {
 147     { &hf_trill_version,
 148       { "Version", "trill.version",
 149         FT_UINT16, BASE_DEC_HEX|BASE_RANGE_STRING, RVALS(version_strings),
 150         TRILL_VERSION_MASK, "The TRILL version number.", HFILL }},
 151     { &hf_trill_reserved,
 152       { "Reserved", "trill.reserved",
 153         FT_UINT16, BASE_DEC_HEX|BASE_RANGE_STRING, RVALS(reserved_strings),
 154         TRILL_RESERVED_MASK, "Bits reserved for future specification.", HFILL }},
 155     { &hf_trill_multi_dst,
 156       { "Multi Destination", "trill.multi_dst",
 157         FT_BOOLEAN, 16, TFS(&multi_dst_strings), TRILL_MULTI_DST_MASK,
 158         "A boolean specifying if this is a multi-destination frame.", HFILL }},
 159     { &hf_trill_op_len,
 160       { "Option Length", "trill.op_len",
 161         FT_UINT16, BASE_DEC_HEX, NULL, TRILL_OP_LEN_MASK,
 162         "The length of the options field of this frame.", HFILL }},
 163     { &hf_trill_hop_cnt,
 164       { "Hop Count", "trill.hop_cnt",
 165         FT_UINT16, BASE_DEC_HEX, NULL, TRILL_HOP_CNT_MASK,
 166         "The remaining hop count for this frame.", HFILL }},
 167     { &hf_trill_egress_nick,
 168       { "Egress/Root RBridge Nickname", "trill.egress_nick",
 169         FT_UINT16, BASE_DEC_HEX|BASE_RANGE_STRING, RVALS(nickname_strings), 0x0,
 170         "The Egress or Distribution Tree Root RBridge Nickname.", HFILL }},
 171     { &hf_trill_ingress_nick,
 172       { "Ingress RBridge Nickname", "trill.ingress_nick",
 173         FT_UINT16, BASE_DEC_HEX|BASE_RANGE_STRING, RVALS(nickname_strings), 0x0,
 174         "The Ingress RBridge Nickname.", HFILL }},
 175     { &hf_trill_options,
 176       { "Options", "trill.options",
 177         FT_BYTES, BASE_NONE, NULL, 0x0,
 178         "The TRILL Options field.", HFILL }}
 179   };
 180
 181   static int *ett[] = {
 182     &ett_trill
 183   };
 184
 185   proto_trill = proto_register_protocol("TRILL", "TRILL", "trill");
 186   proto_register_field_array(proto_trill, hf, array_length(hf));
 187   proto_register_subtree_array(ett, array_length(ett));
 188   trill_handle = register_dissector("trill", dissect_trill, proto_trill);
 189 }
 190
 191 void
 192 proto_reg_handoff_trill(void)
 193 {
 194   dissector_add_uint("ethertype", ETHERTYPE_TRILL, trill_handle);
 195
 196   /*
 197    * RFC 6325, section 4.1.4 "Frame Check Sequence (FCS)", says
 198    *
 199    * "Thus, when a frame is encapsulated, the original FCS is not
 200    * included but is discarded."
 201    *
 202    * meaning that the inner Ethernet frame does *not* include an
 203    * FCS.
 204    */
 205   eth_dissector = find_dissector_add_dependency( "eth_withoutfcs", proto_trill );
 206 }
 207
 208 /*
 209  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 210  *
 211  * Local Variables:
 212  * c-basic-offset: 2
 213  * tab-width: 8
 214  * indent-tabs-mode: nil
 215  * End:
 216  *
 217  * ex: set shiftwidth=2 tabstop=8 expandtab:
 218  * :indentSize=2:tabSize=8:noTabs=true:
 219  */