/* Copyright (C) 2007-2022 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>

 *

 * Packetpool queue handlers. Packet pool is implemented as a stack.

 */

#include "suricata-common.h"

#include "tmqh-packetpool.h"

#include "tm-queuehandlers.h"

#include "tm-threads.h"

#include "threads.h"

#include "decode.h"

#include "tm-modules.h"

#include "packet.h"

#include "util-profiling.h"

#include "util-validate.h"

#include "action-globals.h"

/* Number of freed packet to save for one pool before freeing them. */

#define MAX_PENDING_RETURN_PACKETS 32

static uint32_t max_pending_return_packets = MAX_PENDING_RETURN_PACKETS;

thread_local PktPool thread_pkt_pool;

static inline PktPool *GetThreadPacketPool(void)

{

    return &thread_pkt_pool;

}

/**

 * \brief TmqhPacketpoolRegister

 * \initonly

 */

void TmqhPacketpoolRegister (void)

{

    tmqh_table[TMQH_PACKETPOOL].name = "packetpool";

    tmqh_table[TMQH_PACKETPOOL].InHandler = TmqhInputPacketpool;

    tmqh_table[TMQH_PACKETPOOL].OutHandler = TmqhOutputPacketpool;

}

static int PacketPoolIsEmpty(PktPool *pool)

{

    /* Check local stack first. */

    if (pool->head || pool->return_stack.head)

        return 0;

    return 1;

}

void PacketPoolWait(void)

{

    PktPool *my_pool = GetThreadPacketPool();

    if (PacketPoolIsEmpty(my_pool)) {

        SCMutexLock(&my_pool->return_stack.mutex);

        SC_ATOMIC_ADD(my_pool->return_stack.sync_now, 1);

        SCCondWait(&my_pool->return_stack.cond, &my_pool->return_stack.mutex);

        SCMutexUnlock(&my_pool->return_stack.mutex);

    }

    while(PacketPoolIsEmpty(my_pool))

        cc_barrier();

}

/** \brief a initialized packet

 *

 *  \warning Use *only* at init, not at packet runtime

 */

static void PacketPoolStorePacket(Packet *p)

{

    p->pool = GetThreadPacketPool();

    p->ReleasePacket = PacketPoolReturnPacket;

    PacketPoolReturnPacket(p);

}

static void PacketPoolGetReturnedPackets(PktPool *pool)

{

    SCMutexLock(&pool->return_stack.mutex);

    /* Move all the packets from the locked return stack to the local stack. */

    pool->head = pool->return_stack.head;

    pool->return_stack.head = NULL;

    SCMutexUnlock(&pool->return_stack.mutex);

}

/** \brief Get a new packet from the packet pool

 *

 * Only allocates from the thread's local stack, or mallocs new packets.

 * If the local stack is empty, first move all the return stack packets to

 * the local stack.

 *  \retval Packet pointer, or NULL on failure.

 */

Packet *PacketPoolGetPacket(void)

{

    PktPool *pool = GetThreadPacketPool();

#ifdef DEBUG_VALIDATION

    BUG_ON(pool->initialized == 0);

    BUG_ON(pool->destroyed == 1);

#endif /* DEBUG_VALIDATION */

    if (pool->head) {

        /* Stack is not empty. */

        Packet *p = pool->head;

        pool->head = p->next;

        p->pool = pool;

        PacketReinit(p);

        return p;

    }

    /* Local Stack is empty, so check the return stack, which requires

     * locking. */

    PacketPoolGetReturnedPackets(pool);

    /* Try to allocate again. Need to check for not empty again, since the

     * return stack might have been empty too.

     */

    if (pool->head) {

        /* Stack is not empty. */

        Packet *p = pool->head;

        pool->head = p->next;

        p->pool = pool;

        PacketReinit(p);

        return p;

    }

    /* Failed to allocate a packet, so return NULL. */

    /* Optionally, could allocate a new packet here. */

    return NULL;

}

/** \brief Return packet to Packet pool

 *

 */

void PacketPoolReturnPacket(Packet *p)

{

    PktPool *my_pool = GetThreadPacketPool();

    PktPool *pool = p->pool;

    if (pool == NULL) {

        PacketFree(p);

        return;

    }

    PacketReleaseRefs(p);

#ifdef DEBUG_VALIDATION

    BUG_ON(pool->initialized == 0);

    BUG_ON(pool->destroyed == 1);

    BUG_ON(my_pool->initialized == 0);

    BUG_ON(my_pool->destroyed == 1);

#endif /* DEBUG_VALIDATION */

    if (pool == my_pool) {

        /* Push back onto this thread's own stack, so no locking. */

        p->next = my_pool->head;

        my_pool->head = p;

    } else {

        PktPool *pending_pool = my_pool->pending_pool;

        if (pending_pool == NULL || pending_pool == pool) {

            if (pending_pool == NULL) {

                /* No pending packet, so store the current packet. */

                p->next = NULL;

                my_pool->pending_pool = pool;

                my_pool->pending_head = p;

                my_pool->pending_tail = p;

                my_pool->pending_count = 1;

            } else if (pending_pool == pool) {

                /* Another packet for the pending pool list. */

                p->next = my_pool->pending_head;

                my_pool->pending_head = p;

                my_pool->pending_count++;

            }

            if (SC_ATOMIC_GET(pool->return_stack.sync_now) || my_pool->pending_count > max_pending_return_packets) {

                /* Return the entire list of pending packets. */

                SCMutexLock(&pool->return_stack.mutex);

                my_pool->pending_tail->next = pool->return_stack.head;

                pool->return_stack.head = my_pool->pending_head;

                SC_ATOMIC_RESET(pool->return_stack.sync_now);

                SCCondSignal(&pool->return_stack.cond);

                SCMutexUnlock(&pool->return_stack.mutex);

                /* Clear the list of pending packets to return. */

                my_pool->pending_pool = NULL;

                my_pool->pending_head = NULL;

                my_pool->pending_tail = NULL;

                my_pool->pending_count = 0;

            }

        } else {

            /* Push onto return stack for this pool */

            SCMutexLock(&pool->return_stack.mutex);

            p->next = pool->return_stack.head;

            pool->return_stack.head = p;

            SC_ATOMIC_RESET(pool->return_stack.sync_now);

            SCMutexUnlock(&pool->return_stack.mutex);

            SCCondSignal(&pool->return_stack.cond);

        }

    }

}

void PacketPoolInitEmpty(void)

{

    PktPool *my_pool = GetThreadPacketPool();

#ifdef DEBUG_VALIDATION

    BUG_ON(my_pool->initialized);

    my_pool->initialized = 1;

    my_pool->destroyed = 0;

#endif /* DEBUG_VALIDATION */

    SCMutexInit(&my_pool->return_stack.mutex, NULL);

    SCCondInit(&my_pool->return_stack.cond, NULL);

    SC_ATOMIC_INIT(my_pool->return_stack.sync_now);

}

void PacketPoolInit(void)

{

    extern uint16_t max_pending_packets;

    PktPool *my_pool = GetThreadPacketPool();

#ifdef DEBUG_VALIDATION

    BUG_ON(my_pool->initialized);

    my_pool->initialized = 1;

    my_pool->destroyed = 0;

#endif /* DEBUG_VALIDATION */

    SCMutexInit(&my_pool->return_stack.mutex, NULL);

    SCCondInit(&my_pool->return_stack.cond, NULL);

    SC_ATOMIC_INIT(my_pool->return_stack.sync_now);

    /* pre allocate packets */

    SCLogDebug("preallocating packets... packet size %" PRIuMAX "",

               (uintmax_t)SIZE_OF_PACKET);

    int i = 0;

    for (i = 0; i < max_pending_packets; i++) {

        Packet *p = PacketGetFromAlloc();

        if (unlikely(p == NULL)) {

            FatalError("Fatal error encountered while allocating a packet. Exiting...");

        }

        PacketPoolStorePacket(p);

    }

    //SCLogInfo("preallocated %"PRIiMAX" packets. Total memory %"PRIuMAX"",

    //        max_pending_packets, (uintmax_t)(max_pending_packets*SIZE_OF_PACKET));

}

void PacketPoolDestroy(void)

{

    Packet *p = NULL;

    PktPool *my_pool = GetThreadPacketPool();

#ifdef DEBUG_VALIDATION

    BUG_ON(my_pool && my_pool->destroyed);

#endif /* DEBUG_VALIDATION */

    if (my_pool && my_pool->pending_pool != NULL) {

        p = my_pool->pending_head;

        while (p) {

            Packet *next_p = p->next;

            PacketFree(p);

            p = next_p;

            my_pool->pending_count--;

        }

#ifdef DEBUG_VALIDATION

        BUG_ON(my_pool->pending_count);

#endif /* DEBUG_VALIDATION */

        my_pool->pending_pool = NULL;

        my_pool->pending_head = NULL;

        my_pool->pending_tail = NULL;

    }

    while ((p = PacketPoolGetPacket()) != NULL) {

        PacketFree(p);

    }

#ifdef DEBUG_VALIDATION

    my_pool->initialized = 0;

    my_pool->destroyed = 1;

#endif /* DEBUG_VALIDATION */

}

Packet *TmqhInputPacketpool(ThreadVars *tv)

{

    return PacketPoolGetPacket();

}

void TmqhOutputPacketpool(ThreadVars *t, Packet *p)

{

    bool proot = false;

    SCEnter();

    SCLogDebug("Packet %p, p->root %p, alloced %s", p, p->root, BOOL2STR(p->pool == NULL));

    if (IS_TUNNEL_PKT(p)) {

        SCLogDebug("Packet %p is a tunnel packet: %s",

            p,p->root ? "upper layer" : "tunnel root");

        /* get a lock to access root packet fields */

        SCSpinlock *lock = p->root ? &p->root->persistent.tunnel_lock : &p->persistent.tunnel_lock;

        SCSpinLock(lock);

        if (IS_TUNNEL_ROOT_PKT(p)) {

            SCLogDebug("IS_TUNNEL_ROOT_PKT == TRUE");

            CaptureStatsUpdate(t, p);

            const uint16_t outstanding = TUNNEL_PKT_TPR(p) - TUNNEL_PKT_RTV(p);

            SCLogDebug("root pkt: outstanding %u", outstanding);

            if (outstanding == 0) {

                SCLogDebug("no tunnel packets outstanding, no more tunnel "

                        "packet(s) depending on this root");

                /* if this packet is the root and there are no

                 * more tunnel packets to consider

                 *

                 * return it to the pool */

            } else {

                SCLogDebug("tunnel root Packet %p: outstanding > 0, so "

                        "packets are still depending on this root, setting "

                        "SET_TUNNEL_PKT_VERDICTED", p);

                /* if this is the root and there are more tunnel

                 * packets, return this to the pool. It's still referenced

                 * by the tunnel packets, and we will return it

                 * when we handle them */

                SET_TUNNEL_PKT_VERDICTED(p);

                PACKET_PROFILING_END(p);

                SCSpinUnlock(lock);

                SCReturn;

            }

        } else {

            SCLogDebug("NOT IS_TUNNEL_ROOT_PKT, so tunnel pkt");

            TUNNEL_INCR_PKT_RTV_NOLOCK(p);

            const uint16_t outstanding = TUNNEL_PKT_TPR(p) - TUNNEL_PKT_RTV(p);

            SCLogDebug("tunnel pkt: outstanding %u", outstanding);

            /* all tunnel packets are processed except us. Root already

             * processed. So return tunnel pkt and root packet to the

             * pool. */

            if (outstanding == 0 &&

                    p->root && IS_TUNNEL_PKT_VERDICTED(p->root))

            {

                SCLogDebug("root verdicted == true && no outstanding");

                /* handle freeing the root as well*/

                SCLogDebug("setting proot = 1 for root pkt, p->root %p "

                        "(tunnel packet %p)", p->root, p);

                proot = true;

                /* fall through */

            } else {

                /* root not ready yet, or not the last tunnel packet,

                 * so get rid of the tunnel pkt only */

                SCLogDebug("NOT IS_TUNNEL_PKT_VERDICTED (%s) || "

                        "outstanding > 0 (%u)",

                        (p->root && IS_TUNNEL_PKT_VERDICTED(p->root)) ? "true" : "false",

                        outstanding);

                /* fall through */

            }

        }

        SCSpinUnlock(lock);

        SCLogDebug("tunnel stuff done, move on (proot %d)", proot);

    } else {

        CaptureStatsUpdate(t, p);

    }

    SCLogDebug("[packet %p][%s] %s", p,

            IS_TUNNEL_PKT(p) ? IS_TUNNEL_ROOT_PKT(p) ? "tunnel::root" : "tunnel::leaf"

                             : "no tunnel",

            (p->action & ACTION_DROP) ? "DROP" : "no drop");

    /* we're done with the tunnel root now as well */

    if (proot == true) {

        SCLogDebug("getting rid of root pkt... alloc'd %s", BOOL2STR(p->root->pool == NULL));

        PacketReleaseRefs(p->root);

        p->root->ReleasePacket(p->root);

        p->root = NULL;

    }

    PACKET_PROFILING_END(p);

    PacketReleaseRefs(p);

    p->ReleasePacket(p);

    SCReturn;

}

/**

 *  \brief Release all the packets in the queue back to the packetpool.  Mainly

 *         used by threads that have failed, and wants to return the packets back

 *         to the packetpool.

 *

 *  \param pq Pointer to the packetqueue from which the packets have to be

 *            returned back to the packetpool

 *

 *  \warning this function assumes that the pq does not use locking

 */

void TmqhReleasePacketsToPacketPool(PacketQueue *pq)

{

    Packet *p = NULL;

    if (pq == NULL)

        return;

    while ((p = PacketDequeue(pq)) != NULL) {

        DEBUG_VALIDATE_BUG_ON(p->flow != NULL);

        TmqhOutputPacketpool(NULL, p);

    }

    return;

}

/** number of packets to keep reserved when calculating the pending

 *  return packets count. This assumes we need at max 10 packets in one

 *  PacketPoolWaitForN call. The actual number is 9 now, so this has a

 *  bit of margin. */

#define RESERVED_PACKETS 10

/**

 *  \brief Set the max_pending_return_packets value

 *

 *  Set it to the max pending packets value, divided by the number

 *  of lister threads. Normally, in autofp these are the stream/detect/log

 *  worker threads.

 *

 *  The max_pending_return_packets value needs to stay below the packet

 *  pool size of the 'producers' (normally pkt capture threads but also

 *  flow timeout injection ) to avoid a deadlock where all the 'workers'

 *  keep packets in their return pools, while the capture thread can't

 *  continue because its pool is empty.

 */

void PacketPoolPostRunmodes(void)

{

    extern uint16_t max_pending_packets;

    uint16_t pending_packets = max_pending_packets;

    if (pending_packets < RESERVED_PACKETS) {

        FatalError("'max-pending-packets' setting "

                   "must be at least %d",

                RESERVED_PACKETS);

    }

    uint32_t threads = TmThreadCountThreadsByTmmFlags(TM_FLAG_DETECT_TM);

    if (threads == 0)

        return;

    uint32_t packets = (pending_packets / threads) - 1;

    if (packets < max_pending_return_packets)

        max_pending_return_packets = packets;

    /* make sure to have a margin in the return logic */

    if (max_pending_return_packets >= RESERVED_PACKETS)

        max_pending_return_packets -= RESERVED_PACKETS;

    SCLogDebug("detect threads %u, max packets %u, max_pending_return_packets %u",

            threads, packets, max_pending_return_packets);

}