wireshark/epan/capture_dissectors.c

/* capture_dissectors.c
 * Routines for handling capture dissectors
 *
 * 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"
#define WS_LOG_DOMAIN LOG_DOMAIN_EPAN

#include <glib.h>
#include <stdio.h>
#include <stdlib.h>
#include "packet.h"

#include "capture_dissectors.h"

#include <wsutil/wslog.h>

struct capture_dissector_table {
    GHashTable *hash_table;
    const char *ui_name;
};

struct capture_dissector_handle
{
    const char *name;
    capture_dissector_t dissector;
    protocol_t* protocol;
};

typedef struct capture_dissector_count
{
    guint32 count;
} capture_dissector_count_t;

static GHashTable *registered_dissectors = NULL;

static GHashTable *capture_dissector_tables = NULL;

static void
destroy_capture_dissector_table(void *data)
{
    struct capture_dissector_table *table = (struct capture_dissector_table *)data;

    g_hash_table_destroy(table->hash_table);
    g_free(data);
}

void capture_dissector_init(void)
{
    registered_dissectors = g_hash_table_new_full(g_str_hash, g_str_equal, NULL, NULL);
    capture_dissector_tables = g_hash_table_new_full(g_str_hash, g_str_equal, NULL, destroy_capture_dissector_table);
}

void capture_dissector_cleanup(void)
{
    g_hash_table_destroy(capture_dissector_tables);
    g_hash_table_destroy(registered_dissectors);
}

void register_capture_dissector_table(const char *name, const char *ui_name)
{
    struct capture_dissector_table*	sub_dissectors;

    /* Make sure the registration is unique */
    if(g_hash_table_lookup( capture_dissector_tables, name )) {
        ws_error("The capture dissector table %s (%s) is already registered - are you using a buggy plugin?", name, ui_name);
    }

    sub_dissectors = g_new(struct capture_dissector_table, 1);

    sub_dissectors->hash_table = g_hash_table_new_full( g_direct_hash, g_direct_equal, NULL, NULL );
    sub_dissectors->ui_name = ui_name;
    g_hash_table_insert( capture_dissector_tables, (gpointer)name, (gpointer) sub_dissectors );

}

static capture_dissector_handle_t
new_capture_dissector_handle(capture_dissector_t dissector, int proto, const char *name)
{
    struct capture_dissector_handle* handle;

    handle                = wmem_new(wmem_epan_scope(), struct capture_dissector_handle);
    handle->name          = name;
    handle->dissector     = dissector;
    handle->protocol      = find_protocol_by_id(proto);
    return handle;
}

capture_dissector_handle_t
create_capture_dissector_handle(capture_dissector_t dissector, const int proto)
{
    return new_capture_dissector_handle(dissector, proto, NULL);
}

capture_dissector_handle_t find_capture_dissector(const char *name)
{
    return (capture_dissector_handle_t)g_hash_table_lookup(registered_dissectors, name);
}

capture_dissector_handle_t register_capture_dissector(const char *name, capture_dissector_t dissector, int proto)
{
    capture_dissector_handle_t handle;

    /* Make sure the registration is unique */
    g_assert(g_hash_table_lookup(registered_dissectors, name) == NULL);

    handle = new_capture_dissector_handle(dissector, proto, name);
    g_hash_table_insert(registered_dissectors, (gpointer)name, handle);
    return handle;
}

void capture_dissector_add_uint(const char *name, const guint32 pattern, capture_dissector_handle_t handle)
{
    struct capture_dissector_table*	sub_dissectors;

    if (handle == NULL)
        return;

    /* Make sure table exists */
    sub_dissectors = (struct capture_dissector_table*)g_hash_table_lookup( capture_dissector_tables, name );
    if (sub_dissectors == NULL) {
            fprintf(stderr, "OOPS: Subdissector \"%s\" not found in capture_dissector_tables\n", name);
            if (wireshark_abort_on_dissector_bug)
                    abort();
            return;
    }

    /* Make sure the registration is unique */
    g_assert(g_hash_table_lookup(sub_dissectors->hash_table, GUINT_TO_POINTER(pattern)) == NULL);

    g_hash_table_insert(sub_dissectors->hash_table, GUINT_TO_POINTER(pattern), (gpointer) handle);
}

gboolean try_capture_dissector(const char* name, const guint32 pattern, const guint8 *pd, int offset, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header)
{
    struct capture_dissector_table*	sub_dissectors;
    capture_dissector_handle_t handle;

    sub_dissectors = (struct capture_dissector_table*)g_hash_table_lookup( capture_dissector_tables, name );
    if (sub_dissectors == NULL)
    {
        /* XXX - ASSERT? */
        return FALSE;
    }

    handle = (capture_dissector_handle_t)g_hash_table_lookup(sub_dissectors->hash_table, GUINT_TO_POINTER(pattern));
    if (handle == NULL)
        return FALSE;

    return handle->dissector(pd, offset, len, cpinfo, pseudo_header);
}

gboolean call_capture_dissector(capture_dissector_handle_t handle, const guint8 *pd, int offset, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header)
{
    if (handle == NULL)
        return FALSE;
    return handle->dissector(pd, offset, len, cpinfo, pseudo_header);
}

guint32 capture_dissector_get_count(packet_counts* counts, const int proto)
{
    capture_dissector_count_t* hash_count = (capture_dissector_count_t*)g_hash_table_lookup(counts->counts_hash, GINT_TO_POINTER(proto));
    if (hash_count == NULL)
        return 0;

    return hash_count->count;
}

void capture_dissector_increment_count(capture_packet_info_t *cpinfo, const int proto)
{
    /* See if we already have a counter for the protocol */
    capture_dissector_count_t* hash_count = (capture_dissector_count_t*)g_hash_table_lookup(cpinfo->counts, GINT_TO_POINTER(proto));
    if (hash_count == NULL)
    {
        hash_count = g_new0(capture_dissector_count_t, 1);
        g_hash_table_insert(cpinfo->counts, GINT_TO_POINTER(proto), (gpointer)hash_count);
    }

    hash_count->count++;
}

/*
 * 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:
 */