/** @file

 *

 * Copyright 2025, Daniel Salloum <daniel.salloum@gmail.com>

 *

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

 *

 */

#include "config.h"

#define WS_LOG_DOMAIN "MModuleFile"

#include "mmodule.h"

#include "wtap_module.h"

#include "file_wrappers.h"

static int mmodule_file_type_subtype = -1;

static struct mmodule_phdr *mmodule;

void register_mmodule(void);

bool verify_checksum(FILE_T fh, int *err, char **err_info)

{

    uint32_t checksum=0, tmp;

    if (file_seek(fh, 0x00, SEEK_SET, err) == -1){

        return false;

    }

    while (wtap_read_bytes(fh, &tmp, 4, err, err_info)) {

        checksum += tmp;

    }

    if (file_seek(fh, 0x00, SEEK_SET, err) == -1){

        return false;

    }

    if (checksum == 0)

        return true;

    return false;

}

wtap_open_return_val mmodule_open(wtap *wth, int *err, char **err_info)

{

    uint32_t tmp;

    // Check if a file tag we recognize

    mmodule = g_new(struct mmodule_phdr, 1);

    if (file_seek(wth->fh, 0x00, SEEK_SET, err) < 0) {

        g_free(mmodule);

        return false;

    }

    if (!wtap_read_bytes_or_eof(wth->fh, &tmp, 4, err, err_info)) {

        g_free(mmodule);

        return false;

    }

    uint32_t tag = GUINT32_FROM_LE(tmp);

    if (tag > 10 || tag < 1) {

        g_free(mmodule);

        return WTAP_OPEN_NOT_MINE;

    }

    // Check if a version type we recognize

    if (file_seek(wth->fh, 0x10, SEEK_SET, err) < 0) {

        g_free(mmodule);

        return false;

    }

    if (!wtap_read_bytes_or_eof(wth->fh, &tmp, 4, err, err_info)) {

        g_free(mmodule);

        return false;

    }

    uint32_t vtype = GUINT32_FROM_LE(tmp);

    if (vtype > 3 || vtype < 1) {

        return WTAP_OPEN_NOT_MINE;

    }

    // Reported and actual lengths are not the same

    if (file_seek(wth->fh, 0x00, SEEK_END, err) == -1){

        g_free(mmodule);

        return false;

    }

    uint32_t file_len = (uint32_t) file_tell(wth->fh);

    if (file_seek(wth->fh, 0x20, SEEK_SET, err) == -1){

        g_free(mmodule);

        return false;

    }

    if (!wtap_read_bytes_or_eof(wth->fh, &tmp, 4, err, err_info)) {

        g_free(mmodule);

        return false;

    }

    uint32_t reported_len = GUINT32_FROM_LE(tmp);

    if (reported_len != file_len) {

        g_free(mmodule);

        return WTAP_OPEN_NOT_MINE;

    }

    // Confirm entire file checksum

    if (verify_checksum(wth->fh,err,err_info) == false) {

        g_free(mmodule);

        return WTAP_OPEN_NOT_MINE;

    }

    wth->file_type_subtype = mmodule_file_type_subtype;

    wth->file_encap = WTAP_ENCAP_MMODULE;

    wth->snapshot_length = 0;

    wth->file_tsprec = WTAP_TSPREC_SEC;

    wth->subtype_read = wtap_full_file_read;

    wth->subtype_seek_read = wtap_full_file_seek_read;

    // Explicitly set, in case code gets updated somewhere

    if (file_seek(wth->fh, 0, SEEK_SET, err) == -1) {

        g_free(mmodule);

        return WTAP_OPEN_ERROR;

    }

    return WTAP_OPEN_MINE;

}

static const struct supported_block_type mmodule_blocks_supported[] = {

    /*

     * We support packet blocks, with no comments or other options.

     */

    // Use this if we break it up into different packets

    //{ WTAP_BLOCK_PACKET, MULTIPLE_BLOCKS_SUPPORTED, NO_OPTIONS_SUPPORTED }

    { WTAP_BLOCK_PACKET, ONE_BLOCK_SUPPORTED, NO_OPTIONS_SUPPORTED }

};

static const struct file_type_subtype_info mmodule_info = {

    "Bachmann M-Module file", // description

    "m_module", // name

    "m", // extension

    NULL, // extra extensions

    false, // seek required?

    BLOCKS_SUPPORTED(mmodule_blocks_supported), // num blocks and block_type

    NULL,  // write support?

    NULL,  // open write support ?

    NULL   // We're not a lua writer

};

void register_mmodule(void)

{

    mmodule_file_type_subtype = wtap_register_file_type_subtype(&mmodule_info);

    /*

     * Register name for backwards compatibility with the

     * wtap_filetypes table in Lua.

     */

    wtap_register_backwards_compatibility_lua_name("MMODULE",

                                                   mmodule_file_type_subtype);

}

/*

 * 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:

 */