/* packet-media.c

 * Routines for displaying an undissected media type (default case),

 * based on the generic "data" dissector.

 *

 * (C) Olivier Biot, 2004

 *

 * Refer to the AUTHORS file or the AUTHORS section in the man page

 * for contacting the author(s) of this file.

 *

 * 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 <wsutil/str_util.h>

#include "packet-media-type.h"

void proto_register_media(void);

static int proto_media;

static int hf_media_type;

static int ett_media;

static heur_dissector_list_t heur_subdissector_list;

static dissector_table_t media_type_suffix_table;

static int

dissect_media(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)

{

    int bytes;

    proto_item *ti;

    proto_tree *media_tree = 0;

    media_content_info_t *content_info = (media_content_info_t *)data;

    heur_dtbl_entry_t *hdtbl_entry;

    char* suffix;

    /* XXX - Should we move the other media_type table here, and have

     * dissectors always call this dissector instead of invoking the table,

     * similar to the Ethertype dissector?

     * It would make Decode As with Media Types easier.

     */

    /*

     * RFC 6838 4.2 Naming Requirements

     * "Characters after last plus always specify a structured syntax suffix"

     */

    if (pinfo->match_string &&

        (suffix = strrchr(pinfo->match_string, '+'))) {

        if ((bytes = dissector_try_string_with_data(media_type_suffix_table,

                suffix + 1, tvb, pinfo, tree, true, data)) > 0) {

            return bytes;

        }

    }

    if (dissector_try_heuristic(heur_subdissector_list, tvb, pinfo, tree, &hdtbl_entry, data)) {

        return tvb_reported_length(tvb);

    }

    /* Add media type to the INFO column if it is visible */

    col_append_fstr(pinfo->cinfo, COL_INFO, " (%s)", (pinfo->match_string) ? pinfo->match_string : "");

    if (tree) {

        if ( (bytes = tvb_reported_length(tvb)) > 0 )

        {

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

            media_tree = proto_item_add_subtree(ti, ett_media);

            if (content_info != NULL && content_info->media_str != NULL) {

                /* The media type has parameters */

                proto_tree_add_bytes_format_value(media_tree, hf_media_type, tvb, 0, bytes,

                    NULL, "%s; %s (%d byte%s)",

                    pinfo->match_string, content_info->media_str,

                    bytes, plurality(bytes, "", "s"));

            } else {

                /* The media type has no parameters */

                proto_tree_add_bytes_format_value(media_tree, hf_media_type, tvb, 0, bytes,

                    NULL, "%s (%d byte%s)",

                    pinfo->match_string ? pinfo->match_string : "",

                    bytes, plurality(bytes, "", "s"));

            }

        }

    }

    return tvb_reported_length(tvb);

}

void

proto_register_media(void)

{

    static hf_register_info hf[] = {

      { &hf_media_type,

        { "Media type", "media.type",

          FT_BYTES, BASE_NONE, NULL, 0,

          NULL, HFILL }},

    };

    static int *ett[] = {

        &ett_media

    };

    proto_media = proto_register_protocol ("Media Type", "Media", "media");

    register_dissector("media", dissect_media, proto_media);

    heur_subdissector_list = register_heur_dissector_list_with_description("media", "Media type", proto_media);

    proto_register_field_array(proto_media, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    /*

     * "Media" is used to dissect something whose normal dissector

     * is disabled, so it cannot itself be disabled.

     */

    proto_set_cant_toggle(proto_media);

    /*

     * https://www.iana.org/assignments/media-type-structured-suffix/media-type-structured-suffix.xhtml

     * Structured Suffixes ("zzz" in "xxx/yyy+zzz") can be used as fallback

     * when the exact media type is not registered.

     */

    media_type_suffix_table = register_dissector_table("media_type.suffix",

        "Internet media type structured suffix",

        proto_media, FT_STRING, STRING_CASE_INSENSITIVE);

}

/*

 * 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:

 */