epan/dissectors/packet-macsec.c

   1 /* packet-macsec.c
   2  * Routines for MACSEC dissection
   3  * Copyright 2013, Allan W. Nielsen <anielsen@vitesse.com>
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (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 along
  22  * with this program; if not, write to the Free Software Foundation, Inc.,
  23  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24  */
  25
  26 #include "config.h"
  27
  28 #include <glib.h>
  29
  30 #include <epan/packet.h>
  31 #include <epan/etypes.h>
  32
  33 #define TCI_V_MASK   0x80
  34 #define TCI_ES_MASK  0x40
  35 #define TCI_SC_MASK  0x20
  36 #define TCI_SCB_MASK 0x10
  37 #define TCI_E_MASK   0x08
  38 #define TCI_C_MASK   0x04
  39 #define TCI_AN_MASK  0x03
  40
  41
  42 static dissector_handle_t data_handle;
  43
  44 static int proto_macsec = -1;
  45 static int hf_macsec_TCI                   = -1;
  46 static int hf_macsec_TCI_V                 = -1;
  47 static int hf_macsec_TCI_ES                = -1;
  48 static int hf_macsec_TCI_SC                = -1;
  49 static int hf_macsec_TCI_SCB               = -1;
  50 static int hf_macsec_TCI_E                 = -1;
  51 static int hf_macsec_TCI_C                 = -1;
  52 static int hf_macsec_AN                    = -1;
  53 static int hf_macsec_SL                    = -1;
  54 static int hf_macsec_PN                    = -1;
  55 static int hf_macsec_SCI_System_identifier = -1;
  56 static int hf_macsec_SCI_port_number       = -1;
  57 static int hf_macsec_ICV                   = -1;
  58
  59 /* Initialize the subtree pointers */
  60 static gint ett_macsec = -1;
  61 static gint ett_macsec_tci = -1;
  62
  63 /* Code to actually dissect the packets */
  64 static int dissect_macsec(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {
  65     unsigned    sectag_length,     data_length, icv_length = 16;
  66     unsigned    sectag_offset = 0, data_offset, icv_offset;
  67     guint8      tci_an_field;
  68
  69     proto_item *macsec_item, *tci_item;
  70     proto_tree *macsec_tree, *tci_tree;
  71
  72     tvbuff_t *next_tvb;
  73
  74     tci_an_field = tvb_get_guint8(tvb, 0);
  75
  76     if ((tci_an_field & TCI_V_MASK) != 0) {  /* version must be zero */
  77         return 0;
  78     }
  79
  80     if (tci_an_field & TCI_SC_MASK) {
  81         sectag_length = 14;
  82     } else {
  83         sectag_length = 6;
  84     }
  85
  86     /* Check for short length */
  87     if (tvb_length(tvb) <= (sectag_length + icv_length)) {
  88         return 0;
  89     }
  90
  91     data_offset = sectag_length;
  92     data_length = tvb_length(tvb) - sectag_length - icv_length;
  93     icv_offset  = data_length + data_offset;
  94
  95     next_tvb = tvb_new_subset(tvb, data_offset, data_length, data_length);
  96
  97     col_set_str(pinfo->cinfo, COL_PROTOCOL, "MACSEC");
  98     col_set_str(pinfo->cinfo, COL_INFO, "MACsec frame");
  99
 100     if (tree) {
 101         macsec_item = proto_tree_add_item(tree,
 102                 proto_macsec, tvb, 0, sectag_length, ENC_NA);
 103         macsec_tree = proto_item_add_subtree(macsec_item, ett_macsec);
 104
 105         tci_item = proto_tree_add_uint_format(macsec_tree, hf_macsec_TCI, tvb,
 106                 sectag_offset, 1, tci_an_field,
 107                 "TCI=0x%02x: V=%d, ES=%d, SC=%d, SCB=%d, E=%d, C=%d, AN=%d",
 108                 tci_an_field,
 109                 ((TCI_V_MASK &   tci_an_field) ? 1:0),
 110                 ((TCI_ES_MASK &  tci_an_field) ? 1:0),
 111                 ((TCI_SC_MASK &  tci_an_field) ? 1:0),
 112                 ((TCI_SCB_MASK & tci_an_field) ? 1:0),
 113                 ((TCI_E_MASK &   tci_an_field) ? 1:0),
 114                 ((TCI_C_MASK &   tci_an_field) ? 1:0),
 115                 (TCI_AN_MASK &   tci_an_field));
 116         tci_tree = proto_item_add_subtree(tci_item, ett_macsec_tci);
 117
 118         proto_tree_add_item(tci_tree, hf_macsec_TCI_V, tvb, sectag_offset, 1, ENC_NA);
 119         proto_tree_add_item(tci_tree, hf_macsec_TCI_ES, tvb, sectag_offset, 1, ENC_NA);
 120         proto_tree_add_item(tci_tree, hf_macsec_TCI_SC, tvb, sectag_offset, 1, ENC_NA);
 121         proto_tree_add_item(tci_tree, hf_macsec_TCI_SCB, tvb, sectag_offset, 1, ENC_NA);
 122         proto_tree_add_item(tci_tree, hf_macsec_TCI_E, tvb, sectag_offset, 1, ENC_NA);
 123         proto_tree_add_item(tci_tree, hf_macsec_TCI_C, tvb, sectag_offset, 1, ENC_NA);
 124         proto_tree_add_item(tci_tree, hf_macsec_AN, tvb, sectag_offset, 1, ENC_NA);
 125         proto_tree_add_item(macsec_tree, hf_macsec_SL, tvb, sectag_offset + 1, 1, ENC_NA);
 126         proto_tree_add_item(macsec_tree, hf_macsec_PN, tvb, sectag_offset + 2, 4, ENC_NA);
 127
 128         if (sectag_length == 14) {
 129             proto_tree_add_item(macsec_tree, hf_macsec_SCI_System_identifier,
 130                     tvb, sectag_offset + 6, 6, ENC_NA);
 131             proto_tree_add_item(macsec_tree, hf_macsec_SCI_port_number, tvb,
 132                     sectag_offset + 12, 2, ENC_NA);
 133         }
 134
 135         call_dissector(data_handle, next_tvb, pinfo, tree);
 136
 137         proto_tree_add_item(macsec_tree, hf_macsec_ICV, tvb, icv_offset,
 138                 icv_length, ENC_NA);
 139     }
 140
 141     return tvb_length(tvb);
 142 }
 143
 144 void
 145 proto_register_macsec(void)
 146 {
 147     static hf_register_info hf[] = {
 148         { &hf_macsec_TCI, { "TAG Control Information", "macsec.TCI",FT_UINT8,
 149                             BASE_HEX, NULL, 0xfc, NULL, HFILL} },
 150         { &hf_macsec_TCI_V, { "VER", "macsec.TCI.V", FT_UINT8, BASE_HEX,
 151                                 NULL, 0x80, NULL, HFILL} },
 152         { &hf_macsec_TCI_ES, { "ES", "macsec.TCI.ES", FT_UINT8, BASE_HEX, NULL,
 153                                  0x40, NULL, HFILL} },
 154         { &hf_macsec_TCI_SC, { "SC", "macsec.TCI.SC", FT_UINT8, BASE_HEX, NULL,
 155                                  0x20, NULL, HFILL} },
 156         { &hf_macsec_TCI_SCB, { "SCB", "macsec.TCI.SCB", FT_UINT8, BASE_HEX,
 157                                   NULL, 0x10, NULL, HFILL} },
 158         { &hf_macsec_TCI_E, { "E", "macsec.TCI.E", FT_UINT8, BASE_HEX, NULL,
 159                                 0x08, NULL, HFILL} },
 160         { &hf_macsec_TCI_C, { "C", "macsec.TCI.C", FT_UINT8, BASE_HEX, NULL,
 161                                 0x04, NULL, HFILL} },
 162         { &hf_macsec_AN, { "AN", "macsec.AN", FT_UINT8,
 163                              BASE_HEX, NULL, 0x03, NULL, HFILL} },
 164         { &hf_macsec_SL, { "Short length", "macsec.SL", FT_UINT8, BASE_DEC,
 165                              NULL, 0xFF, NULL, HFILL} },
 166         { &hf_macsec_PN, { "Packet number", "macsec.PN", FT_UINT32, BASE_DEC,
 167                              NULL, 0xFFFFFFFF, NULL, HFILL} },
 168         { &hf_macsec_SCI_System_identifier,
 169             { "System Identifier", "macsec.SCI.SytemIdentifier",
 170                 FT_ETHER, BASE_NONE, NULL, 0x00, NULL, HFILL} },
 171         { &hf_macsec_SCI_port_number,
 172             { "Port number", "macsec.SCI.port_number",
 173                 FT_UINT16, BASE_DEC, NULL, 0xFFFF, NULL, HFILL} },
 174         { &hf_macsec_ICV, { "ICV", "macsec.ICV",
 175                               FT_BYTES, BASE_NONE, NULL, 0x00, NULL, HFILL} }
 176     };
 177
 178     /* Setup protocol subtree array */
 179     static gint *ett[] = {
 180         &ett_macsec,
 181         &ett_macsec_tci
 182     };
 183
 184     /* Register the protocol name and description */
 185     proto_macsec = proto_register_protocol("802.1AE Secure tag", "macsec", "macsec");
 186
 187     /* Required function calls to register the header fields and subtrees used */
 188     proto_register_field_array(proto_macsec, hf, array_length(hf));
 189     proto_register_subtree_array(ett, array_length(ett));
 190 }
 191
 192 void
 193 proto_reg_handoff_macsec(void)
 194 {
 195     dissector_handle_t macsec_handle;
 196     data_handle = find_dissector("data");
 197     macsec_handle = new_create_dissector_handle(dissect_macsec, proto_macsec);
 198     dissector_add_uint("ethertype", ETHERTYPE_MACSEC, macsec_handle);
 199 }
 200
 201 /*
 202  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 203  *
 204  * Local variables:
 205  * c-basic-offset: 4
 206  * tab-width: 8
 207  * indent-tabs-mode: nil
 208  * End:
 209  *
 210  * vi: set shiftwidth=4 tabstop=8 expandtab:
 211  * :indentSize=4:tabSize=8:noTabs=true:
 212  */
 213