/* packet-bananna.c

 * Routines for the Twisted Banana serialization protocol dissection

 * Copyright 2009, Gerald Combs <gerald@wireshark.org>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

/*

 * Based on "Banana Protocol Specifications"

 * https://twisted.org/documents/16.1.1/core/specifications/banana.html

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/expert.h>

void proto_register_banana(void);

void proto_reg_handoff_banana(void);

/* Initialize the protocol and registered fields */

static int proto_banana;

static int hf_banana_list;

static int hf_banana_int;

static int hf_banana_string;

static int hf_banana_neg_int;

static int hf_banana_float;

static int hf_banana_lg_int;

static int hf_banana_lg_neg_int;

static int hf_banana_pb;

/* Initialize the subtree pointers */

static int ett_banana;

static int ett_list;

static expert_field ei_banana_unknown_type;

static expert_field ei_banana_too_many_value_bytes;

static expert_field ei_banana_length_too_long;

static expert_field ei_banana_value_too_large;

static expert_field ei_banana_pb_error;

static dissector_handle_t banana_handle;

#define BE_LIST         0x80

#define BE_INT          0x81

#define BE_STRING       0x82

#define BE_NEG_INT      0x83

#define BE_FLOAT        0x84

#define BE_LG_INT       0x85

#define BE_LG_NEG_INT   0x86

#define BE_PB           0x87

#define is_element(b) (b >= BE_LIST && b <= BE_PB)

static const value_string type_vals[] = {

    { BE_LIST,          "List" },

    { BE_INT,           "Integer" },

    { BE_STRING,        "String" },

    { BE_NEG_INT,       "Negative Integer" },

    { BE_FLOAT,         "Float" },

    { BE_LG_INT,        "Large Integer" },

    { BE_LG_NEG_INT,    "Large Negative Integer" },

    { BE_PB,            "pb Profile"},

    { 0, NULL }

};

static const value_string pb_vals[] = {

    { 0x01, "None" },

    { 0x02, "class" },

    { 0x03, "dereference" },

    { 0x04, "reference" },

    { 0x05, "dictionary" },

    { 0x06, "function" },

    { 0x07, "instance" },

    { 0x08, "list" },

    { 0x09, "module" },

    { 0x0a, "persistent" },

    { 0x0b, "tuple" },

    { 0x0c, "unpersistable" },

    { 0x0d, "copy" },

    { 0x0e, "cache" },

    { 0x0f, "cached" },

    { 0x10, "remote" },

    { 0x11, "local" },

    { 0x12, "lcache" },

    { 0x13, "version" },

    { 0x14, "login" },

    { 0x15, "password" },

    { 0x16, "challenge" },

    { 0x17, "logged_in" },

    { 0x18, "not_logged_in" },

    { 0x19, "cachemessage" },

    { 0x1a, "message" },

    { 0x1b, "answer" },

    { 0x1c, "error" },

    { 0x1d, "decref" },

    { 0x1e, "decache" },

    { 0x1f, "uncache" },

    { 0,    NULL }

};

#define MAX_ELEMENT_VAL 2147483647 /* Max TE value */

#define MAX_ELEMENT_INT_LEN 4

#define MAX_ELEMENT_VAL_LEN 8

/* Dissect the packets */

static int

// NOLINTNEXTLINE(misc-no-recursion)

dissect_banana_element(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset) {

    proto_item *ti;

    proto_tree *list_tree;

    uint8_t byte = 0;

    int64_t val = 0;

    int val_len = 0;

    int start_offset = offset;

    int old_offset;

    int i;

    /* Accumulate our value/length 'til we hit a valid type */

    while (tvb_reported_length_remaining(tvb, offset) > 0) {

        byte = tvb_get_uint8(tvb, offset);

        offset++;

        if (byte & 0x80) {

            if (is_element(byte)) {

                break;

            } else {

                expert_add_info_format(pinfo, NULL, &ei_banana_unknown_type, "Unknown type %u", byte);

            }

        } else {

            val_len++;

            if (val_len > MAX_ELEMENT_VAL_LEN) {

                expert_add_info(pinfo, NULL, &ei_banana_too_many_value_bytes);

            }

            val += byte + (val << 7);

        }

    }

    /* Type */

    switch (byte) {

        case BE_LIST:

            if (val > MAX_ELEMENT_VAL) {

                expert_add_info_format(pinfo, NULL, &ei_banana_length_too_long, "List length %" PRId64 " longer than we can handle", val);

            }

            ti = proto_tree_add_uint_format_value(tree, hf_banana_list, tvb, start_offset, offset - start_offset - 1, (uint32_t) val, "(%d items)", (int) val);

            list_tree = proto_item_add_subtree(ti, ett_list);

            for (i = 0; i < val; i++) {

                old_offset = offset;

                increment_dissection_depth(pinfo);

                offset += dissect_banana_element(tvb, pinfo, list_tree, offset);

                decrement_dissection_depth(pinfo);

                if (offset <= old_offset) {

                    return offset - start_offset;

                }

            }

            break;

        case BE_INT:

            if (val > MAX_ELEMENT_VAL) {

                expert_add_info_format(pinfo, NULL, &ei_banana_value_too_large, "Integer value %" PRId64 " too large", val);

            }

            proto_tree_add_uint(tree, hf_banana_int, tvb, start_offset, offset - start_offset, (uint32_t) val);

            break;

        case BE_STRING:

            if (val > MAX_ELEMENT_VAL) {

                expert_add_info_format(pinfo, NULL, &ei_banana_length_too_long, "String length %" PRId64 " longer than we can handle", val);

            }

            proto_tree_add_item(tree, hf_banana_string, tvb, offset, (uint32_t) val, ENC_ASCII);

            offset += (int) val;

            break;

        case BE_NEG_INT:

            if (val > MAX_ELEMENT_VAL) {

                expert_add_info_format(pinfo, NULL, &ei_banana_value_too_large, "Integer value -%" PRId64 " too large", val);

            }

            proto_tree_add_int(tree, hf_banana_neg_int, tvb, start_offset, offset - start_offset, (int32_t) val * -1);

            break;

        case BE_FLOAT:

            proto_tree_add_item(tree, hf_banana_float, tvb, offset, 8, ENC_BIG_ENDIAN);

            offset += 8;

            break;

        case BE_LG_INT:

            proto_tree_add_item(tree, hf_banana_lg_int, tvb, start_offset, offset - start_offset, ENC_NA);

            break;

        case BE_LG_NEG_INT:

            proto_tree_add_item(tree, hf_banana_lg_neg_int, tvb, start_offset, offset - start_offset, ENC_NA);

            break;

        case BE_PB:

            if (val_len > 1) {

                expert_add_info(pinfo, NULL, &ei_banana_pb_error);

            }

            /*

             * The spec says the pb dictionary value comes after the tag.

             * In real-world captures it comes before.

             */

            proto_tree_add_item(tree, hf_banana_pb, tvb, offset - 2, 1, ENC_BIG_ENDIAN);

            break;

        default:

            return 0;

    }

    return offset - start_offset;

}

static int

dissect_banana(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {

    uint8_t byte = 0;

    int offset = 0, old_offset;

    proto_item *ti;

    proto_tree *banana_tree;

    /* Check that there's enough data */

    if (tvb_reported_length(tvb) < 2)

        return 0;

    /* Fill in our protocol and info columns */

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

    while (tvb_reported_length_remaining(tvb, offset) > 0 && offset < MAX_ELEMENT_VAL_LEN) {

        byte = tvb_get_uint8(tvb, offset);

        if (is_element(byte))

            break;

        offset++;

    }

    col_add_fstr(pinfo->cinfo, COL_INFO, "First element: %s",

        val_to_str(pinfo->pool, byte, type_vals, "Unknown type: %u"));

    /* Create display subtree for the protocol */

    ti = proto_tree_add_item(tree, proto_banana, tvb, 0, -1, ENC_NA);

    banana_tree = proto_item_add_subtree(ti, ett_banana);

    offset = 0;

    old_offset = -1;

    while (offset > old_offset) {

        old_offset = offset;

        offset += dissect_banana_element(tvb, pinfo, banana_tree, offset);

    }

    /* Return the amount of data this dissector was able to dissect */

    return tvb_reported_length(tvb);

}

/* Register the protocol with Wireshark */

void

proto_register_banana(void)

{

    static hf_register_info hf[] = {

        { &hf_banana_list,

            { "List Length", "banana.list",

                FT_UINT32, BASE_DEC, NULL, 0,

                "Banana list", HFILL }

        },

        { &hf_banana_int,

            { "Integer", "banana.int",

                FT_UINT32, BASE_DEC, NULL, 0,

                "Banana integer", HFILL }

        },

        { &hf_banana_string,

            { "String", "banana.string",

                FT_STRING, BASE_NONE, NULL, 0,

                "Banana string", HFILL }

        },

        { &hf_banana_neg_int,

            { "Negative Integer", "banana.neg_int",

                FT_INT32, BASE_DEC, NULL, 0,

                "Banana negative integer", HFILL }

        },

        { &hf_banana_float,

            { "Float", "banana.float",

                FT_DOUBLE, BASE_NONE, NULL, 0,

                "Banana float", HFILL }

        },

        { &hf_banana_lg_int,

            { "Float", "banana.lg_int",

                FT_BYTES, BASE_NONE, NULL, 0,

                "Banana large integer", HFILL }

        },

        { &hf_banana_lg_neg_int,

            { "Float", "banana.lg_neg_int",

                FT_BYTES, BASE_NONE, NULL, 0,

                "Banana large negative integer", HFILL }

        },

        { &hf_banana_pb,

            { "pb Profile Value", "banana.pb",

                FT_UINT8, BASE_HEX, VALS(pb_vals), 0,

                "Banana Perspective Broker Profile Value", HFILL }

        }

    };

    expert_module_t* expert_banana;

    /* Setup protocol subtree array */

    static int *ett[] = {

        &ett_banana,

        &ett_list

    };

    static ei_register_info ei[] = {

        { &ei_banana_unknown_type, { "banana.unknown_type", PI_UNDECODED, PI_ERROR, "Unknown type", EXPFILL }},

        { &ei_banana_too_many_value_bytes, { "banana.too_many_value_bytes", PI_UNDECODED, PI_ERROR, "Too many value/length bytes", EXPFILL }},

        { &ei_banana_length_too_long, { "banana.length_too_long", PI_UNDECODED, PI_ERROR, "Length too long", EXPFILL }},

        { &ei_banana_value_too_large, { "banana.value_too_large", PI_MALFORMED, PI_ERROR, "Value too large", EXPFILL }},

        { &ei_banana_pb_error, { "banana.pb_error", PI_MALFORMED, PI_ERROR, "More than 1 byte before pb", EXPFILL }},

    };

    /* Register the protocol name and description */

    proto_banana = proto_register_protocol("Twisted Banana", "Banana", "banana");

    /* Required function calls to register the header fields and subtrees used */

    proto_register_field_array(proto_banana, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    expert_banana = expert_register_protocol(proto_banana);

    expert_register_field_array(expert_banana, ei, array_length(ei));

    banana_handle = register_dissector("banana", dissect_banana, proto_banana);

}

void

proto_reg_handoff_banana(void)

{

    dissector_add_uint_range_with_preference("tcp.port", "", banana_handle);

}

/*

 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html

 *

 * Local variables:

 * c-basic-offset: 4

 * tab-width: 8

 * indent-tabs-mode: nil

 * End:

 *

 * ex: set shiftwidth=4 tabstop=8 expandtab:

 * :indentSize=4:tabSize=8:noTabs=true:

 */