/* Copyright (C) 2007-2010 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>
 *
 * Simple output queue handler that makes sure all packets of the same flow
 * are sent to the same queue. This is done by simply hashing the flow's
 * memory address as thats readable from a packet without the need to lock
 * the flow itself.
 *
 * \todo we can also think about a queue handler that takes queue load into
 *       account.
 */

#include "suricata.h"
#include "packet-queue.h"
#include "decode.h"
#include "threads.h"
#include "threadvars.h"
#include "tmqh-flow.h"

#include "tm-queuehandlers.h"

#include "conf.h"
#include "util-unittest.h"

Packet *TmqhInputFlow(ThreadVars *t);
void TmqhOutputFlowActiveFlows(ThreadVars *t, Packet *p);
void TmqhOutputFlowActivePackets(ThreadVars *t, Packet *p);
void TmqhOutputFlowRoundRobin(ThreadVars *t, Packet *p);
void *TmqhOutputFlowSetupCtx(char *queue_str);
void TmqhFlowRegisterTests(void);

TmqhFlowCtx *tmqh_flow_outctx = NULL;

void TmqhFlowRegister (void) {
    tmqh_table[TMQH_FLOW].name = "flow";
    tmqh_table[TMQH_FLOW].InHandler = TmqhInputFlow;
    tmqh_table[TMQH_FLOW].OutHandlerCtxSetup = TmqhOutputFlowSetupCtx;
    tmqh_table[TMQH_FLOW].OutHandlerCtxFree = NULL;
    tmqh_table[TMQH_FLOW].RegisterTests = TmqhFlowRegisterTests;

    char *scheduler = NULL;
    if (ConfGet("autofp-scheduler", &scheduler) == 1) {
        if (strcmp(scheduler, "round_robin") == 0) {
            SCLogInfo("AutoFP mode using \"Round Robin\" Q Handler");
            tmqh_table[TMQH_FLOW].OutHandler = TmqhOutputFlowRoundRobin;
        } else if (strcmp(scheduler, "active_flows") == 0) {
            SCLogInfo("AutoFP mode using \"Active Flows\" Q Handler");
            tmqh_table[TMQH_FLOW].OutHandler = TmqhOutputFlowActiveFlows;
        } else if (strcmp(scheduler, "active_packets") == 0) {
            SCLogInfo("AutoFP mode using \"Active Packets\" Q Handler");
            tmqh_table[TMQH_FLOW].OutHandler = TmqhOutputFlowActivePackets;
        } else {
            SCLogError(SC_ERR_INVALID_YAML_CONF_ENTRY, "Invalid entry \"%s\" for "
                       "autofp-scheduler in conf.  Killing engine.", scheduler);
            exit(EXIT_FAILURE);
        }
    } else {
        SCLogInfo("AutoFP mode using default \"Round Robin\" Q Handler");
        tmqh_table[TMQH_FLOW].OutHandler = TmqhOutputFlowRoundRobin;
    }

    return;
}

/* same as 'simple' */
Packet *TmqhInputFlow(ThreadVars *tv)
{
    PacketQueue *q = &trans_q[tv->inq->id];

    SCMutexLock(&q->mutex_q);
    if (q->len == 0) {
        /* if we have no packets in queue, wait... */
        SCCondWait(&q->cond_q, &q->mutex_q);
    }

    SCPerfSyncCountersIfSignalled(tv, 0);

    if (q->len > 0) {
        Packet *p = PacketDequeue(q);
        SCMutexUnlock(&q->mutex_q);
        return p;
    } else {
        /* return NULL if we have no pkt. Should only happen on signals. */
        SCMutexUnlock(&q->mutex_q);
        return NULL;
    }
}

static int StoreQueueId(TmqhFlowCtx *ctx, char *name) {
    Tmq *tmq = TmqGetQueueByName(name);
    if (tmq == NULL) {
        tmq = TmqCreateQueue(SCStrdup(name));
        if (tmq == NULL)
            return -1;
    }
    tmq->writer_cnt++;

    uint16_t id = tmq->id;

    if (ctx->queues == NULL) {
        ctx->size = 1;
        ctx->queues = SCMalloc(ctx->size * sizeof(TmqhFlowMode));
        memset(ctx->queues, 0, ctx->size * sizeof(TmqhFlowMode));
        if (ctx->queues == NULL) {
            return -1;
        }
    } else {
        ctx->size++;
        ctx->queues = SCRealloc(ctx->queues, ctx->size * sizeof(TmqhFlowMode));
        if (ctx->queues == NULL) {
            return -1;
        }
        memset(ctx->queues + (ctx->size - 1), 0, sizeof(TmqhFlowMode));
    }
    ctx->queues[ctx->size - 1].q = &trans_q[id];
    SC_ATOMIC_INIT(ctx->queues[ctx->size - 1].active_flows);

    return 0;
}

/** \brief setup the queue handlers ctx
 *
 *  Parses a comma separated string "queuename1,queuename2,etc"
 *  and sets the ctx up to devide flows over these queue's.
 *
 *  \param queue_str comma separated string with output queue names
 *  \retval ctx queues handlers ctx or NULL in error
 */
void *TmqhOutputFlowSetupCtx(char *queue_str) {
    if (queue_str == NULL || strlen(queue_str) == 0)
        return NULL;

    TmqhFlowCtx *ctx = SCMalloc(sizeof(TmqhFlowCtx));
    if (ctx == NULL)
        return NULL;
    memset(ctx,0x00,sizeof(TmqhFlowCtx));

    char *str = SCStrdup(queue_str);
    if (str == NULL) {
        goto error;
    }
    char *tstr = str;

    /* parse the comma separated string */
    do {
        char *comma = strchr(tstr,',');
        if (comma != NULL) {
            *comma = '\0';
            char *qname = tstr;
            int r = StoreQueueId(ctx,qname);
            if (r < 0)
                goto error;
        } else {
            char *qname = tstr;
            int r = StoreQueueId(ctx,qname);
            if (r < 0)
                goto error;
        }
        tstr = comma ? (comma + 1) : comma;
    } while (tstr != NULL);

    tmqh_flow_outctx = ctx;

    SCFree(str);
    return (void *)ctx;
error:
    SCFree(ctx);
    if (str != NULL)
        SCFree(str);
    return NULL;
}

/** \brief select the queue to output to based on flow
 *  \param tv thread vars
 *  \param p packet
 */
void TmqhOutputFlowRoundRobin(ThreadVars *tv, Packet *p)
{
    int32_t qid = 0;

    TmqhFlowCtx *ctx = (TmqhFlowCtx *)tv->outctx;

    /* if no flow we use the first queue,
     * should be rare */
    if (p->flow != NULL) {
        qid = p->flow->autofp_tmqh_flow_qid;
        if (qid == -1) {
            p->flow->autofp_tmqh_flow_qid = qid = ctx->round_robin_idx++;
            ctx->round_robin_idx = ctx->round_robin_idx % ctx->size;
            SC_ATOMIC_ADD(ctx->queues[qid].active_flows, 1);
            ctx->queues[qid].total_flows++;
        }
        ctx->queues[qid].total_packets++;
    } else {
        qid = ctx->last++;

        if (ctx->last == ctx->size)
            ctx->last = 0;
    }

    PacketQueue *q = ctx->queues[qid].q;
    SCMutexLock(&q->mutex_q);
    PacketEnqueue(q, p);
    SCCondSignal(&q->cond_q);
    SCMutexUnlock(&q->mutex_q);
}

/** \brief select the queue to output to based on flow
 *  \param tv thread vars
 *  \param p packet
 */
void TmqhOutputFlowActivePackets(ThreadVars *tv, Packet *p)
{
    int32_t qid = 0;

    TmqhFlowCtx *ctx = (TmqhFlowCtx *)tv->outctx;

    /* if no flow we use the first queue,
     * should be rare */
    if (p->flow != NULL) {
        qid = p->flow->autofp_tmqh_flow_qid;
        if (qid == -1) {
            uint16_t i = 0;
            int lowest_id = 0;
            TmqhFlowMode *queues = ctx->queues;
            uint32_t lowest = queues[i].q->len;
            for (i = 1; i < ctx->size; i++) {
                if (queues[i].q->len < lowest) {
                    lowest = queues[i].q->len;
                    lowest_id = i;
                }
            }
            p->flow->autofp_tmqh_flow_qid = qid = lowest_id;
            SC_ATOMIC_ADD(ctx->queues[qid].active_flows, 1);
            queues[qid].total_flows++;
        }
        ctx->queues[qid].total_packets++;
    } else {
        qid = ctx->last++;

        if (ctx->last == ctx->size)
            ctx->last = 0;
    }

    PacketQueue *q = ctx->queues[qid].q;
    SCMutexLock(&q->mutex_q);
    PacketEnqueue(q, p);
    SCCondSignal(&q->cond_q);
    SCMutexUnlock(&q->mutex_q);
}

/** \brief select the queue to output to based on flow
 *  \param tv thread vars
 *  \param p packet
 */
void TmqhOutputFlowActiveFlows(ThreadVars *tv, Packet *p)
{
    int32_t qid = 0;

    TmqhFlowCtx *ctx = (TmqhFlowCtx *)tv->outctx;

    /* if no flow we use the first queue,
     * should be rare */
    if (p->flow != NULL) {
        qid = p->flow->autofp_tmqh_flow_qid;
        if (qid == -1) {
            uint32_t i = 0;
            int lowest_id = 0;
            uint32_t lowest = ctx->queues[i].active_flows_sc_atomic__;
            for (i = 1; i < ctx->size; i++) {
                if (ctx->queues[i].active_flows_sc_atomic__ < lowest) {
                    lowest = ctx->queues[i].active_flows_sc_atomic__;
                    lowest_id = i;
                }
            }
            p->flow->autofp_tmqh_flow_qid = qid = lowest_id;
            SC_ATOMIC_ADD(ctx->queues[qid].active_flows, 1);
            ctx->queues[qid].total_flows++;
        }
        ctx->queues[qid].total_packets++;
    } else {
        qid = ctx->last++;

        if (ctx->last == ctx->size)
            ctx->last = 0;
    }

    PacketQueue *q = ctx->queues[qid].q;
    SCMutexLock(&q->mutex_q);
    PacketEnqueue(q, p);
    SCCondSignal(&q->cond_q);
    SCMutexUnlock(&q->mutex_q);
}

void TmqhFlowPrintStatistics(void)
{
    uint32_t i;

    SCLogInfo("AutoFP - Total flow handler queues - %" PRIu16,
              tmqh_flow_outctx->size);
    for (i = 0; i < tmqh_flow_outctx->size; i++) {
        SCLogInfo("AutoFP - Total Packets - Queue %"PRIu32 " - %"PRIu64 , i,
                  tmqh_flow_outctx->queues[i].total_packets);
    }
    for (i = 0; i < tmqh_flow_outctx->size; i++) {
        SCLogInfo("AutoFP - Total Flows - Queue %"PRIu32 " - %"PRIu64 , i,
                  tmqh_flow_outctx->queues[i].total_flows);
    }

    return;
}

#ifdef UNITTESTS

#if 0
static int TmqhOutputFlowSetupCtxTest01(void) {
    int retval = 0;
    Tmq *tmq = NULL;

    TmqResetQueues();

    tmq = TmqCreateQueue("queue1");
    if (tmq == NULL)
        goto end;
    tmq = TmqCreateQueue("queue2");
    if (tmq == NULL)
        goto end;
    tmq = TmqCreateQueue("another");
    if (tmq == NULL)
        goto end;
    tmq = TmqCreateQueue("yetanother");
    if (tmq == NULL)
        goto end;

    char *str = "queue1,queue2,another,yetanother";
    void *ctx = TmqhOutputFlowSetupCtx(str);

    if (ctx == NULL)
        goto end;

    TmqhFlowCtx *fctx = (TmqhFlowCtx *)ctx;

    if (fctx->size != 4)
        goto end;

    if (fctx->queues == NULL)
        goto end;

    if (fctx->queues[0] != 0)
        goto end;
    if (fctx->queues[1] != 1)
        goto end;
    if (fctx->queues[2] != 2)
        goto end;
    if (fctx->queues[3] != 3)
        goto end;

    retval = 1;
end:
    TmqResetQueues();
    return retval;
}

static int TmqhOutputFlowSetupCtxTest02(void) {
    int retval = 0;
    Tmq *tmq = NULL;

    TmqResetQueues();

    tmq = TmqCreateQueue("queue1");
    if (tmq == NULL)
        goto end;
    tmq = TmqCreateQueue("queue2");
    if (tmq == NULL)
        goto end;
    tmq = TmqCreateQueue("another");
    if (tmq == NULL)
        goto end;
    tmq = TmqCreateQueue("yetanother");
    if (tmq == NULL)
        goto end;

    char *str = "queue1";
    void *ctx = TmqhOutputFlowSetupCtx(str);

    if (ctx == NULL)
        goto end;

    TmqhFlowCtx *fctx = (TmqhFlowCtx *)ctx;

    if (fctx->size != 1)
        goto end;

    if (fctx->queues == NULL)
        goto end;

    if (fctx->queues[0] != 0)
        goto end;

    retval = 1;
end:
    TmqResetQueues();
    return retval;
}

static int TmqhOutputFlowSetupCtxTest03(void) {
    int retval = 0;

    TmqResetQueues();

    char *str = "queue1,queue2,another,yetanother";
    void *ctx = TmqhOutputFlowSetupCtx(str);

    if (ctx == NULL)
        goto end;

    TmqhFlowCtx *fctx = (TmqhFlowCtx *)ctx;

    if (fctx->size != 4)
        goto end;

    if (fctx->queues == NULL)
        goto end;

    if (fctx->queues[0] != 0)
        goto end;
    if (fctx->queues[1] != 1)
        goto end;
    if (fctx->queues[2] != 2)
        goto end;
    if (fctx->queues[3] != 3)
        goto end;

    retval = 1;
end:
    TmqResetQueues();
    return retval;
}
#endif

#endif /* UNITTESTS */

void TmqhFlowRegisterTests(void) {
#ifdef UNITTESTS
#if 0
    UtRegisterTest("TmqhOutputFlowSetupCtxTest01", TmqhOutputFlowSetupCtxTest01, 1);
    UtRegisterTest("TmqhOutputFlowSetupCtxTest02", TmqhOutputFlowSetupCtxTest02, 1);
    UtRegisterTest("TmqhOutputFlowSetupCtxTest03", TmqhOutputFlowSetupCtxTest03, 1);
#endif
#endif
}