app-layer-events.c

/* Copyright (C) 2014 Open Information Security Foundation
 *
 * You can copy, redistribute or modify this Program under the terms of
 * the GNU General Public License version 2 as published by the Free
 * Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

/**
 * \file
 *
 * \author Victor Julien <victor@inliniac.net>
 * \author Anoop Saldanha <anoopsaldanha@gmail.com>
 */

#include "suricata-common.h"
#include "decode.h"
#include "flow.h"
#include "app-layer-events.h"
#include "app-layer-parser.h"
#include "util-enum.h"

/* events raised during protocol detection are stored in the
 * packets storage, not in the flow. */
SCEnumCharMap app_layer_event_pkt_table[ ] = {
    { "APPLAYER_MISMATCH_PROTOCOL_BOTH_DIRECTIONS",
      APPLAYER_MISMATCH_PROTOCOL_BOTH_DIRECTIONS },
    { "APPLAYER_WRONG_DIRECTION_FIRST_DATA",
      APPLAYER_WRONG_DIRECTION_FIRST_DATA },
    { "APPLAYER_DETECT_PROTOCOL_ONLY_ONE_DIRECTION",
      APPLAYER_DETECT_PROTOCOL_ONLY_ONE_DIRECTION },
    { "APPLAYER_PROTO_DETECTION_SKIPPED",
      APPLAYER_PROTO_DETECTION_SKIPPED },
    { NULL,
      -1 },
};

int AppLayerGetPktEventInfo(const char *event_name, int *event_id)
{
    *event_id = SCMapEnumNameToValue(event_name, app_layer_event_pkt_table);
    if (*event_id == -1) {
        SCLogError(SC_ERR_INVALID_ENUM_MAP, "event \"%s\" not present in "
                   "app-layer-event's packet event table.",  event_name);
        /* this should be treated as fatal */
        return -1;
    }

    return 0;
}

#define DECODER_EVENTS_BUFFER_STEPS 8

/**
 * \brief Set an app layer decoder event.
 *
 * \param sevents Pointer to a AppLayerDecoderEvents pointer. If *sevents is NULL
 *                memory will be allocated.
 * \param event   The event to be stored.
 */
void AppLayerDecoderEventsSetEventRaw(AppLayerDecoderEvents **sevents, uint8_t event)
{
    if (*sevents == NULL) {
        AppLayerDecoderEvents *new_devents = SCMalloc(sizeof(AppLayerDecoderEvents));
        if (new_devents == NULL)
            return;

        memset(new_devents, 0, sizeof(AppLayerDecoderEvents));
        *sevents = new_devents;

    }
    if ((*sevents)->cnt == UCHAR_MAX) {
        /* we're full */
        return;
    }
    if ((*sevents)->cnt == (*sevents)->events_buffer_size) {
        int steps = DECODER_EVENTS_BUFFER_STEPS;
        if (UCHAR_MAX - (*sevents)->cnt < steps)
            steps = UCHAR_MAX - (*sevents)->cnt < steps;

        void *ptr = SCRealloc((*sevents)->events,
                              ((*sevents)->cnt + steps) * sizeof(uint8_t));
        if (ptr == NULL) {
            /* couldn't grow buffer, but no reason to free old
             * so we keep the events that may already be here */
            return;
        }
        (*sevents)->events = ptr;
        (*sevents)->events_buffer_size += steps;
    }

    (*sevents)->events[(*sevents)->cnt++] = event;
}

/**
 * \brief Set an app layer decoder event.
 *
 * \param f            Pointer to a flow containing DecoderEvents pointer head.  If
 *                     the head points to a DecoderEvents instance, a
 *                     new instance would be created and the pointer head would
 *                     would be updated with this new instance
 * \param event        The event to be stored.
 */
void AppLayerDecoderEventsSetEvent(Flow *f, uint8_t event)
{
    AppLayerDecoderEvents *events = AppLayerParserGetDecoderEvents(f->alparser);
    AppLayerDecoderEvents *new = events;
    AppLayerDecoderEventsSetEventRaw(&events, event);
    if (events != new)
        AppLayerParserSetDecoderEvents(f->alparser, events);
}

void AppLayerDecoderEventsResetEvents(AppLayerDecoderEvents *events)
{
    if (events != NULL)
        events->cnt = 0;
}


void AppLayerDecoderEventsFreeEvents(AppLayerDecoderEvents **events)
{
    if (events && *events != NULL) {
        if ((*events)->events != NULL)
            SCFree((*events)->events);
        SCFree(*events);
        *events = NULL;
    }
}