aboutsummaryrefslogtreecommitdiffstats
path: root/epan/dissectors/packet-macsec.c
blob: ade66eae4e84a4479b2a8d2d7a6763508b5aa6ca (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
/* packet-macsec.c
 * Routines for IEEE 802.1AE MACsec dissection
 * Copyright 2013, Allan W. Nielsen <anielsen@vitesse.com>
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"

#include <epan/packet.h>
#include <epan/etypes.h>

void proto_register_macsec(void);
void proto_reg_handoff_macsec(void);

/* TCI/AN field masks */
#define TCI_MASK     0xFC
#define TCI_V_MASK   0x80
#define TCI_ES_MASK  0x40
#define TCI_SC_MASK  0x20
#define TCI_SCB_MASK 0x10
#define TCI_E_MASK   0x08
#define TCI_C_MASK   0x04
#define AN_MASK      0x03


static int proto_macsec = -1;
static int hf_macsec_TCI                   = -1;
static int hf_macsec_TCI_V                 = -1;
static int hf_macsec_TCI_ES                = -1;
static int hf_macsec_TCI_SC                = -1;
static int hf_macsec_TCI_SCB               = -1;
static int hf_macsec_TCI_E                 = -1;
static int hf_macsec_TCI_C                 = -1;
static int hf_macsec_AN                    = -1;
static int hf_macsec_SL                    = -1;
static int hf_macsec_PN                    = -1;
static int hf_macsec_SCI_system_identifier = -1;
static int hf_macsec_SCI_port_identifier   = -1;
static int hf_macsec_ICV                   = -1;

/* Initialize the subtree pointers */
static gint ett_macsec = -1;
static gint ett_macsec_tci = -1;

/* Code to actually dissect the packets */
static int dissect_macsec(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {
    unsigned    sectag_length, data_length, icv_length;
    unsigned    data_offset, icv_offset;
    guint8      tci_an_field;

    proto_item *macsec_item;
    proto_tree *macsec_tree;

    tvbuff_t *next_tvb;

    tci_an_field = tvb_get_guint8(tvb, 0);

    if ((tci_an_field & TCI_V_MASK) != 0) {  /* version must be zero */
        return 0;
    }

    icv_length = 16;  /* Fixed size for version 0 */

    if (tci_an_field & TCI_SC_MASK) {
        sectag_length = 14;  /* optional SCI present */
    } else {
        sectag_length = 6;
    }

    /* Check for short length */
    if (tvb_captured_length(tvb) <= (sectag_length + icv_length)) {
        return 0;
    }

    /* Get the payload section */
    data_offset = sectag_length;
    data_length = tvb_captured_length(tvb) - sectag_length - icv_length;
    icv_offset  = data_length + data_offset;

    next_tvb = tvb_new_subset_length(tvb, data_offset, data_length);

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "MACSEC");
    col_set_str(pinfo->cinfo, COL_INFO, "MACsec frame");

    if (tree) {
        macsec_item = proto_tree_add_item(tree,
                proto_macsec, tvb, 0, sectag_length, ENC_NA);
        macsec_tree = proto_item_add_subtree(macsec_item, ett_macsec);

        static const int * flags[] = {
            &hf_macsec_TCI_V,
            &hf_macsec_TCI_ES,
            &hf_macsec_TCI_SC,
            &hf_macsec_TCI_SCB,
            &hf_macsec_TCI_E,
            &hf_macsec_TCI_C,
            NULL
        };

        proto_tree_add_bitmask_with_flags(macsec_tree, tvb, 0,
                hf_macsec_TCI, ett_macsec_tci, flags, ENC_NA, BMT_NO_TFS);

        proto_tree_add_item(macsec_tree, hf_macsec_AN, tvb, 0, 1, ENC_NA);
        proto_tree_add_item(macsec_tree, hf_macsec_SL, tvb, 1, 1, ENC_NA);
        proto_tree_add_item(macsec_tree, hf_macsec_PN, tvb, 2, 4, ENC_BIG_ENDIAN);

        if (sectag_length == 14) {
            proto_tree_add_item(macsec_tree, hf_macsec_SCI_system_identifier,
                    tvb, 6, 6, ENC_NA);
            proto_tree_add_item(macsec_tree, hf_macsec_SCI_port_identifier, tvb,
                    12, 2, ENC_BIG_ENDIAN);
        }

        proto_tree_add_item(macsec_tree, hf_macsec_ICV, tvb, icv_offset,
                icv_length, ENC_NA);
    }

    call_data_dissector(next_tvb, pinfo, tree);

    return tvb_captured_length(tvb);
}

void
proto_register_macsec(void)
{
    static hf_register_info hf[] = {
        { &hf_macsec_TCI,
            { "TCI", "macsec.TCI", FT_UINT8, BASE_HEX,
              NULL, TCI_MASK, "TAG Control Information", HFILL }
        },
        { &hf_macsec_TCI_V,
            { "VER", "macsec.TCI.V", FT_UINT8, BASE_HEX,
              NULL, TCI_V_MASK, "Version", HFILL }
        },
        { &hf_macsec_TCI_ES,
            { "ES", "macsec.TCI.ES", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), TCI_ES_MASK, "End Station", HFILL }
        },
        { &hf_macsec_TCI_SC,
            { "SC", "macsec.TCI.SC", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), TCI_SC_MASK, "Secure Channel", HFILL }
        },
        { &hf_macsec_TCI_SCB,
            { "SCB", "macsec.TCI.SCB", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), TCI_SCB_MASK, "Single Copy Broadcast", HFILL }
        },
        { &hf_macsec_TCI_E,
            { "E", "macsec.TCI.E", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), TCI_E_MASK, "Encryption", HFILL }
        },
        { &hf_macsec_TCI_C,
            { "C", "macsec.TCI.C", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), TCI_C_MASK, "Changed Text", HFILL }
        },
        { &hf_macsec_AN,
            { "AN", "macsec.AN", FT_UINT8, BASE_HEX,
              NULL, AN_MASK, "Association Number", HFILL }
        },
        { &hf_macsec_SL,
            { "Short length", "macsec.SL", FT_UINT8, BASE_DEC,
              NULL, 0, NULL, HFILL }
        },
        { &hf_macsec_PN,
            { "Packet number", "macsec.PN", FT_UINT32, BASE_DEC,
              NULL, 0, NULL, HFILL }
        },
        { &hf_macsec_SCI_system_identifier,
            { "System Identifier", "macsec.SCI.system_identifier", FT_ETHER, BASE_NONE,
                NULL, 0, NULL, HFILL }
        },
        { &hf_macsec_SCI_port_identifier,
            { "Port Identifier", "macsec.SCI.port_identifier", FT_UINT16, BASE_DEC,
              NULL, 0, NULL, HFILL }
        },
        { &hf_macsec_ICV,
            { "ICV", "macsec.ICV", FT_BYTES, BASE_NONE,
              NULL, 0, NULL, HFILL }
        }
    };

    /* Setup protocol subtree array */
    static gint *ett[] = {
        &ett_macsec,
        &ett_macsec_tci
    };

    /* Register the protocol name and description */
    proto_macsec = proto_register_protocol("802.1AE Security tag", "MACsec", "macsec");

    /* Required function calls to register the header fields and subtrees used */
    proto_register_field_array(proto_macsec, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
}

void
proto_reg_handoff_macsec(void)
{
    dissector_handle_t macsec_handle;
    macsec_handle = create_dissector_handle(dissect_macsec, proto_macsec);
    dissector_add_uint("ethertype", ETHERTYPE_MACSEC, macsec_handle);
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 4
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * vi: set shiftwidth=4 tabstop=8 expandtab:
 * :indentSize=4:tabSize=8:noTabs=true:
 */