detect-engine-state.h

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/* Copyright (C) 2007-2013 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.
 */

/**
 * \ingroup sigstate
 *
 * @{
 */

/**
 * \file
 *
 * \brief Data structures and function prototypes for keeping
 *        state for the detection engine.
 *
 * \author Victor Julien <victor@inliniac.net>
 * \author Anoop Saldanha <anoopsaldanha@gmail.com>
 */


#ifndef __DETECT_ENGINE_STATE_H__
#define __DETECT_ENGINE_STATE_H__

#define DETECT_ENGINE_INSPECT_SIG_NO_MATCH 0
#define DETECT_ENGINE_INSPECT_SIG_MATCH 1
#define DETECT_ENGINE_INSPECT_SIG_CANT_MATCH 2
/** indicate that the file inspection portion of a sig didn't match.
 *  This is used to handle state keeping as the detect engine is still
 *  only marginally aware of files. */
#define DETECT_ENGINE_INSPECT_SIG_CANT_MATCH_FILES 3
/** hack to work around a file inspection limitation. Since there can be
 *  multiple files in a TX and the detection engine really don't know
 *  about that, we have to give the file inspection engine a way to
 *  indicate that one of the files matched, but that there are still
 *  more files that have ongoing inspection. */
#define DETECT_ENGINE_INSPECT_SIG_MATCH_MORE_FILES 4

/** number of DeStateStoreItem's in one DeStateStore object */
#define DE_STATE_CHUNK_SIZE             15

/* per sig flags */
#define DE_STATE_FLAG_FULL_INSPECT              BIT_U32(0)
#define DE_STATE_FLAG_SIG_CANT_MATCH            BIT_U32(1)
/* flag set if file inspecting sig did not match, but might need to be
 * re-evaluated for a new file in a tx */
#define DE_STATE_ID_FILE_INSPECT                2UL
#define DE_STATE_FLAG_FILE_INSPECT              BIT_U32(DE_STATE_ID_FILE_INSPECT)

/* first bit position after the built-ins */
#define DE_STATE_FLAG_BASE                      3UL

/* state flags
 *
 * Used by app-layer-parsers to notify us that new files
 * are available in the tx.
 */
#define DETECT_ENGINE_STATE_FLAG_FILE_NEW       BIT_U8(0)

typedef struct DeStateStoreItem_ {
    uint32_t flags;
    SigIntId sid;
} DeStateStoreItem;

typedef struct DeStateStore_ {
    DeStateStoreItem store[DE_STATE_CHUNK_SIZE];
    struct DeStateStore_ *next;
} DeStateStore;

typedef struct DetectEngineStateDirection_ {
    DeStateStore *head;
    DeStateStore *tail;
    SigIntId cnt;
    uint16_t filestore_cnt;
    uint8_t flags;
    /* coccinelle: DetectEngineStateDirection:flags:DETECT_ENGINE_STATE_FLAG_ */
} DetectEngineStateDirection;

typedef struct DetectEngineState_ {
    DetectEngineStateDirection dir_state[2];
} DetectEngineState;

// TODO
typedef struct DetectTransaction_ {
    void *tx_ptr;
    const uint64_t tx_id;
    DetectEngineStateDirection *de_state;
    const uint64_t detect_flags;            /* detect flags get/set from/to applayer */
    uint64_t prefilter_flags;               /* prefilter flags for direction, to be updated by prefilter code */
    const uint64_t prefilter_flags_orig;    /* prefilter flags for direction, before prefilter has run */
    const int tx_progress;
    const int tx_end_state;
} DetectTransaction;

/**
 * \brief Alloc a DetectEngineState object.
 *
 * \retval Alloc'd instance of DetectEngineState.
 */
DetectEngineState *DetectEngineStateAlloc(void);

/**
 * \brief Frees a DetectEngineState object.
 *
 * \param state DetectEngineState instance to free.
 */
void DetectEngineStateFree(DetectEngineState *state);

/**
 *  \brief Update the inspect id.
 *
 *  \param f unlocked flow
 *  \param flags direction and disruption flags
 */
void DeStateUpdateInspectTransactionId(Flow *f, const uint8_t flags,
        const bool tag_txs_as_inspected);

void DetectEngineStateResetTxs(Flow *f);

void DeStateRegisterTests(void);


void DetectRunStoreStateTx(
        const SigGroupHead *sgh,
        Flow *f, void *tx, uint64_t tx_id,
        const Signature *s,
        uint32_t inspect_flags, uint8_t flow_flags,
        const uint16_t file_no_match);

void DetectRunStoreStateTxFileOnly(
        const SigGroupHead *sgh,
        Flow *f, void *tx, uint64_t tx_id,
        const uint8_t flow_flags,
        const uint16_t file_no_match);

#endif /* __DETECT_ENGINE_STATE_H__ */

/**
 * @}
 */