/* packet-ayiya.c
 * Anything in Anything protocol
 * Copyright 2008, Jelmer Vernooij <jelmer@samba.org>
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * ref: http://unfix.org/~jeroen/archive/drafts/draft-massar-v6ops-ayiya-02.html#anchor4
 */

#include "config.h"

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

void proto_register_ayiya(void);
void proto_reg_handoff_ayiya(void);

static dissector_table_t ip_dissector_table;

static int proto_ayiya = -1;
static int hf_id_len = -1;
static int hf_id_type = -1;
static int hf_sig_len = -1;
static int hf_hash_method = -1;
static int hf_auth_method = -1;
static int hf_opcode = -1;
static int hf_next_header = -1;
static int hf_epoch = -1;
static int hf_identity = -1;
static int hf_signature = -1;

static gint ett_ayiya = -1;

static dissector_handle_t ayiya_handle = NULL;

static const value_string identity_types[] = {
    { 0x0, "None" },
    { 0x1, "Integer" },
    { 0x2, "ASCII string" },
    { 0, NULL }
};

static const value_string hash_methods[] = {
    { 0x0, "No hash" },
    { 0x1, "MD5" },
    { 0x2, "SHA1" },
    { 0, NULL }
};

static const value_string auth_methods[] = {
    { 0x0, "No authentication" },
    { 0x1, "Hash using a Shared Secret" },
    { 0x2, "Hash using a public/private key method" },
    { 0, NULL }
};

#define OPCODE_FORWARD 1

static const value_string opcodes[] = {
    { 0x0, "No Operation / Heartbeat" },
    { 0x1, "Forward" },
    { 0x2, "Echo Request" },
    { 0x3, "Echo Request and Forward" },
    { 0x4, "Echo Response" },
    { 0x5, "MOTD" },
    { 0x6, "Query Request" },
    { 0x7, "Query Response" },
    { 0, NULL }
};

#define UDP_PORT_AYIYA          5072

static int
dissect_ayiya(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
    proto_tree *ayiya_tree;
    int offset = 0;
    int idlen, siglen, ayiya_len;
    guint8 next_header, opcode;
    tvbuff_t *payload;

    idlen = 1 << tvb_get_bits8(tvb, 0, 4);
    siglen = tvb_get_bits8(tvb, 8, 4) * 4;
    opcode = tvb_get_bits8(tvb, 20, 4);
    next_header = tvb_get_guint8(tvb, 3);

    ayiya_len = 8+idlen+siglen;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "AYIYA");

    if (tree) {
        proto_item *ti;
        ti = proto_tree_add_protocol_format( tree, proto_ayiya, tvb,
                                             offset, ayiya_len, "AYIYA" );
        ayiya_tree = proto_item_add_subtree(ti, ett_ayiya);

        proto_tree_add_bits_item(ayiya_tree, hf_id_len, tvb, 0, 4, ENC_BIG_ENDIAN);
        proto_tree_add_bits_item(ayiya_tree, hf_id_type, tvb, 4, 4, ENC_BIG_ENDIAN);
        proto_tree_add_bits_item(ayiya_tree, hf_sig_len, tvb, 8, 4, ENC_BIG_ENDIAN);
        proto_tree_add_bits_item(ayiya_tree, hf_hash_method, tvb, 12, 4, ENC_BIG_ENDIAN);
        proto_tree_add_bits_item(ayiya_tree, hf_auth_method, tvb, 16, 4, ENC_BIG_ENDIAN);
        proto_tree_add_bits_item(ayiya_tree, hf_opcode, tvb, 20, 4, ENC_BIG_ENDIAN);
        proto_tree_add_uint_format_value(ayiya_tree, hf_next_header, tvb,
                                   3, 1, next_header,
                                   "%s (0x%02x)",
                                   ipprotostr(next_header), next_header);
        proto_tree_add_item(ayiya_tree, hf_epoch, tvb, 4, 4, ENC_TIME_SECS|ENC_BIG_ENDIAN);
        proto_tree_add_item(ayiya_tree, hf_identity, tvb, 8, idlen, ENC_NA);
        proto_tree_add_item(ayiya_tree, hf_signature, tvb, 8+idlen, siglen, ENC_NA);
    }
    offset = ayiya_len;
    switch (opcode) {
    case OPCODE_FORWARD:
        payload = tvb_new_subset_remaining(tvb, offset);
        dissector_try_uint(ip_dissector_table, next_header, payload, pinfo, tree);
        break;
    }

    return tvb_captured_length(tvb);
}

void
proto_register_ayiya(void)
{
    static hf_register_info hf[] = {
        { &hf_id_len,
          { "Identity field length", "ayiya.idlen", FT_UINT8,
            BASE_HEX, NULL, 0x0, NULL, HFILL
          }
        },
        { &hf_id_type,
          { "Identity field type", "ayiya.idtype", FT_UINT8,
            BASE_HEX, VALS(identity_types), 0x0, NULL, HFILL
          }
        },
        { &hf_sig_len,
          { "Signature Length", "ayiya.siglen", FT_UINT8,
            BASE_HEX, NULL, 0x0, NULL, HFILL
          }
        },
        { &hf_hash_method,
          { "Hash method", "ayiya.hashmethod", FT_UINT8,
            BASE_HEX, VALS(hash_methods), 0x0, NULL, HFILL
          }
        },
        { &hf_auth_method,
          { "Authentication method", "ayiya.authmethod", FT_UINT8,
            BASE_HEX, VALS(auth_methods), 0x0, NULL, HFILL
          }
        },
        { &hf_opcode,
          { "Operation Code", "ayiya.opcode", FT_UINT8,
            BASE_HEX, VALS(opcodes), 0x0, NULL, HFILL
          }
        },
        { &hf_next_header,
          { "Next Header", "ayiya.nextheader", FT_UINT8,
            BASE_HEX, NULL, 0x0, NULL, HFILL
          }
        },
        { &hf_epoch,
          { "Epoch", "ayiya.epoch", FT_ABSOLUTE_TIME,
            ABSOLUTE_TIME_LOCAL, NULL, 0x0, NULL, HFILL
          }
        },
        { &hf_identity,
          { "Identity", "ayiya.identity", FT_BYTES,
            BASE_NONE, NULL, 0x0, NULL, HFILL
          }
        },
        { &hf_signature,
          { "Signature", "ayiya.signature", FT_BYTES,
            BASE_NONE, NULL, 0x0, NULL, HFILL
          }
        },
    };
    static gint *ett[] = {
        &ett_ayiya,
    };

    proto_ayiya = proto_register_protocol("Anything in Anything Protocol",
                          "AYIYA", "ayiya");
    ayiya_handle = register_dissector("ayiya", dissect_ayiya, proto_ayiya);
    proto_register_field_array(proto_ayiya, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
}

void
proto_reg_handoff_ayiya(void)
{
    dissector_add_uint_with_preference("udp.port", UDP_PORT_AYIYA, ayiya_handle);

    ip_dissector_table = find_dissector_table("ip.proto");
}

/*
 * Editor modelines  -  https://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:
 */