/** BEGIN COPYRIGHT BLOCK
 * Copyright (C) 2001 Sun Microsystems, Inc. Used by permission.
 * Copyright (C) 2021 Red Hat, Inc.
 * All rights reserved.
 *
 * License: GPL (version 3 or any later version).
 * See LICENSE for details.
 * END COPYRIGHT BLOCK **/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif


/* repl5_inc_protocol.c */
/*

 The Prot_Incremental object implements the DS 5.0 multi-supplier incremental
 replication protocol.


Stuff to do:

- Need to figure out how asynchronous events end up in here. They are:
  - entry updated in replicated area.
  - backoff timeout
  - enter/leave.

Perhaps these events should be properties of the main protocol.
*/

#include "repl5.h"
#include "windowsrepl.h"
#include "windows_prot_private.h"
#include "slap.h" /* PSEUDO_ATTR_UNHASHED */
#include "repl5_ruv.h"

#include "cl5_api.h"
#include "slapi-plugin.h"
extern int slapi_log_urp;


/*** from proto-slap.h ***/
void ava_done(struct ava *ava);

typedef struct windows_inc_private
{
    char *ruv; /* RUV on remote replica (use diff type for this? - ggood */
    Backoff_Timer *backoff;
    Repl_Protocol *rp;
    pthread_mutex_t *lock;
    PRUint32 eventbits;
} windows_inc_private;


/* Various states the incremental protocol can pass through */
#define STATE_START 0 /* ONREPL - should we rename this - we don't use it just to start up? */
#define STATE_WAIT_WINDOW_OPEN 1
#define STATE_WAIT_CHANGES 2
#define STATE_READY_TO_ACQUIRE 3
#define STATE_BACKOFF_START 4 /* ONREPL - can we combine BACKOFF_START and BACKOFF states? */
#define STATE_BACKOFF 5
#define STATE_SENDING_UPDATES 6
#define STATE_STOP_FATAL_ERROR 7
#define STATE_STOP_FATAL_ERROR_PART2 8
#define STATE_STOP_NORMAL_TERMINATION 9

/* Events (synchronous and asynchronous; these are bits) */
#define EVENT_WINDOW_OPENED 1
#define EVENT_WINDOW_CLOSED 2
#define EVENT_TRIGGERING_CRITERIA_MET 4 /* ONREPL - should we rename this to EVENT_CHANGE_AVAILABLE */
#define EVENT_BACKOFF_EXPIRED 8
#define EVENT_REPLICATE_NOW 16
#define EVENT_PROTOCOL_SHUTDOWN 32
#define EVENT_AGMT_CHANGED 64
#define EVENT_RUN_DIRSYNC 128

#define UPDATE_NO_MORE_UPDATES 201
#define UPDATE_TRANSIENT_ERROR 202
#define UPDATE_FATAL_ERROR 203
#define UPDATE_SCHEDULE_WINDOW_CLOSED 204
#define UPDATE_CONNECTION_LOST 205
#define UPDATE_TIMEOUT 206
#define UPDATE_YIELD 207

/* Return codes from examine_update_vector */
#define EXAMINE_RUV_PRISTINE_REPLICA 401
#define EXAMINE_RUV_GENERATION_MISMATCH 402
#define EXAMINE_RUV_REPLICA_TOO_OLD 403
#define EXAMINE_RUV_OK 404
#define EXAMINE_RUV_PARAM_ERROR 405

#define MAX_CHANGES_PER_SESSION 10000
/*
 * Maximum time to wait between replication sessions. If we
 * don't see any updates for a period equal to this interval,
 * we go ahead and start a replication session, just to be safe
 */
#define MAX_WAIT_BETWEEN_SESSIONS 300 /* 5 minutes */
/*
 * tests if the protocol has been shutdown and we need to quit
 * event_occurred resets the bits in the bit flag, so whoever tests for shutdown
 * resets the flags, so the next one who tests for shutdown won't get it, so we
 * also look at the terminate flag
 */
#define PROTOCOL_IS_SHUTDOWN(prp) (event_occurred(prp, EVENT_PROTOCOL_SHUTDOWN) || prp->terminate)

/* Forward declarations */
static PRUint32 event_occurred(Private_Repl_Protocol *prp, PRUint32 event);
static void reset_events(Private_Repl_Protocol *prp);
static void protocol_sleep(Private_Repl_Protocol *prp, int32_t duration);
static int send_updates(Private_Repl_Protocol *prp, RUV *ruv, PRUint32 *num_changes_sent, int do_send);
static void windows_inc_backoff_expired(time_t timer_fire_time, void *arg);
static int windows_examine_update_vector(Private_Repl_Protocol *prp, RUV *ruv);
static const char *state2name(int state);
static const char *event2name(int event);
static const char *acquire2name(int code);
static void periodic_dirsync(time_t when, void *arg);

static Slapi_Eq_Context dirsync = NULL;
/*
 * It's specifically ok to delete a protocol instance that
 * is currently running. The instance will be shut down, and
 * then resources will be freed. Since a graceful shutdown is
 * attempted, this function may take some time to complete.
 */
static void
windows_inc_delete(Private_Repl_Protocol **prpp)
{
    int rc;
    windows_inc_private *prp_priv = (windows_inc_private *)(*prpp)->private;
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_inc_delete\n");
    /* First, stop the protocol if it isn't already stopped */
    /* Then, delete all resources used by the protocol */
    rc = slapi_eq_cancel_rel(dirsync);
    slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                  "windows_inc_delete - dirsync: %p, rval: %d\n", dirsync, rc);
    /* if backoff is set, delete it (from EQ, as well) */
    if (prp_priv->backoff) {
        backoff_delete(&prp_priv->backoff);
    }
    if (!(*prpp)->stopped) {
        (*prpp)->stopped = 1;
        (*prpp)->stop(*prpp);
    }
    pthread_mutex_destroy(&((*prpp)->lock));
    pthread_cond_destroy(&(*prpp)->cvar);
    slapi_ch_free((void **)&(*prpp)->private);
    slapi_ch_free((void **)prpp);

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_inc_delete\n");
}

/* helper function */
void
w_set_pause_and_busy_time(Private_Repl_Protocol *prp, long *pausetime, long *busywaittime)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> w_set_pause_and_busy_time\n");
    /* If neither are set, set busy time to its default */
    if (!*pausetime && !*busywaittime) {
        *busywaittime = repl5_get_backoff_min(prp);
    }
    /* pause time must be at least 1 more than the busy backoff time */
    if (*pausetime && !*busywaittime) {
        /*
       * user specified a pause time but no busy wait time - must
       * set busy wait time to 1 less than pause time - if pause
       * time is 1, we must set it to 2
       */
        if (*pausetime < 2) {
            *pausetime = 2;
        }
        *busywaittime = *pausetime - 1;
    } else if (!*pausetime && *busywaittime) {
        /*
       * user specified a busy wait time but no pause time - must
       * set pause time to 1 more than busy wait time
       */
        *pausetime = *busywaittime + 1;
    } else if (*pausetime && *busywaittime && *pausetime <= *busywaittime) {
        /*
       * user specified both pause and busy wait times, but the pause
       * time was <= busy wait time - pause time must be at least
       * 1 more than the busy wait time
       */
        *pausetime = *busywaittime + 1;
    }
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= w_set_pause_and_busy_time\n");
}

/*
 * Do the incremental protocol.
 *
 * What's going on here? This thing is a state machine. It has the
 * following states:
 *
 * State transition table:
 *
 * Curr State       Condition/Event                        Next State
 * ----------       ------------                           -----------
 * START            schedule window is open                ACQUIRE_REPLICA
 *                  schedule window is closed              WAIT_WINDOW_OPEN
 * WAIT_WINDOW_OPEN schedule change                        START
 *                  replicate now                          ACQUIRE_REPLICA
 *                  schedule window opens                  ACQUIRE_REPLICA
 * ACQUIRE_REPLICA  acquired replica                        SEND_CHANGES
 *                  failed to acquire - transient error    START_BACKOFF
 *                  failed to acquire - fatal error        STOP_FATAL_ERROR
 * SEND_CHANGES     can't update                           CONSUMER_NEEDS_REINIT
 *                  no changes to send                     WAIT_CHANGES
 *                  can't send - thransient error          START_BACKOF
 *                  can't send - window closed             WAIT_WINDOW_OPEN
 *                  can'r send - fatal error               STOP_FATAL_ERROR
 * START_BACKOF     replicate now                          ACQUIRE_REPLICA
 *                  schedule changes                       START
 *                  schedule window closes                 WAIT_WINDOW_OPEN
 *                  backoff expires & can acquire          SEND_CHANGES
 *                  backoff expires & can't acquire-trans  BACKOFF
 *                  backoff expires & can't acquire-fatal  STOP_FATAL_ERROR
 * BACKOF           replicate now                          ACQUIRE_REPLICA
 *                  schedule changes                       START
 *                  schedule window closes                 WAIT_WINDOW_OPEN
 *                  backoff expires & can acquire          SEND_CHANGES
 *                  backoff expires & can't acquire-trans  BACKOFF
 *                  backoff expires & can't acquire-fatal  STOP_FATAL_ERROR
 * WAIT_CHANGES     schedule window closes                 WAIT_WINDOW_OPEN
 *                  replicate_now                          ACQUIRE_REPLICA
 *                  change available                       ACQUIRE_REPLICA
 *                  schedule_change                        START
 */

/*
 * DBDB: what follows is quite possibly the worst code I have ever seen.
 * Unfortunately we chose not to re-write it when we did the windows sync version.
 */

/*
 * Main state machine for the incremental protocol. This routine will,
 * under normal circumstances, not return until the protocol is shut
 * down.
 */
static void
windows_inc_run(Private_Repl_Protocol *prp)
{
    int current_state = STATE_START;
    int next_state = STATE_START;
    windows_inc_private *prp_priv = (windows_inc_private *)prp->private;
    int done = 0;
    int e1 = 0;
    RUV *ruv = NULL;
    Replica *replica = NULL;
    int wait_change_timer_set = 0;
    time_t last_start_time = 0;
    PRUint32 num_changes_sent = 0;
    /* use a different backoff timer strategy for ACQUIRE_REPLICA_BUSY errors */
    PRBool use_busy_backoff_timer = PR_FALSE;
    long pausetime = 0;
    long busywaittime = 0;
    unsigned long current_interval = 0;
    unsigned long interval = 0;
    int one_way;

    PRBool run_dirsync = PR_FALSE;

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_inc_run\n");

    prp->stopped = 0;
    prp->terminate = 0;

    windows_private_load_dirsync_cookie(prp->agmt);

    do {
        int rc = 0;

        one_way = windows_private_get_one_way(prp->agmt);
        /* Take action, based on current state, and compute new state. */
        switch (current_state) {
        case STATE_START:

            dev_debug("windows_inc_run(STATE_START)");
            if (PROTOCOL_IS_SHUTDOWN(prp)) {
                done = 1;
                break;
            }

            /*
                 * Our initial state. See if we're in a schedule window. If
                 * so, then we're ready to acquire the replica and see if it
                 * needs any updates from us. If not, then wait for the window
                 * to open.
                 */
            if (agmt_schedule_in_window_now(prp->agmt)) {
                next_state = STATE_READY_TO_ACQUIRE;
            } else {
                next_state = STATE_WAIT_WINDOW_OPEN;
            }

            /* we can get here from other states because some events happened and were
                   not cleared. For instance when we wake up in STATE_WAIT_CHANGES state.
                   Since this is a fresh start state, we should clear all events */
            /* ONREPL - this does not feel right - we should take another look
                   at this state machine */
            reset_events(prp);

            /* Cancel any linger timer that might be in effect... */
            windows_conn_cancel_linger(prp->conn);
            /* ... and disconnect, if currently connected */
            windows_conn_disconnect(prp->conn);
            /* get the new pause time, if any */
            pausetime = agmt_get_pausetime(prp->agmt);
            /* get the new busy wait time, if any */
            busywaittime = agmt_get_busywaittime(prp->agmt);
            if (pausetime || busywaittime) {
                /* helper function to make sure they are set correctly */
                w_set_pause_and_busy_time(prp, &pausetime, &busywaittime);
            }

            /* Check if the interval changed */
            interval = windows_private_get_sync_interval(prp->agmt) * 1000;
            if (interval != current_interval) {
                current_interval = interval;
                if (dirsync) {
                    int rv = slapi_eq_cancel_rel(dirsync);
                    slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                                  "windows_inc_run - Cancelled dirsync: %p, rval: %d\n",
                                  dirsync, rv);
                }
                dirsync = slapi_eq_repeat_rel(periodic_dirsync, (void *)prp,
                                              slapi_current_rel_time_t(), interval);
                slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                              "windows_inc_run - New dirsync: %p\n", dirsync);
            }

            break;

        case STATE_WAIT_WINDOW_OPEN:
            /*
                 * We're waiting for a schedule window to open. If one did,
                 * or we receive a "replicate now" event, then start a protocol
                 * session immediately. If the replication schedule changed, go
                 * back to start.  Otherwise, go back to sleep.
                 */
            dev_debug("windows_inc_run(STATE_WAIT_WINDOW_OPEN)");
            if (PROTOCOL_IS_SHUTDOWN(prp)) {
                done = 1;
                break;
            } else if (event_occurred(prp, EVENT_WINDOW_OPENED)) {
                next_state = STATE_READY_TO_ACQUIRE;
            } else if (event_occurred(prp, EVENT_REPLICATE_NOW)) {
                next_state = STATE_READY_TO_ACQUIRE;
            } else if (event_occurred(prp, EVENT_AGMT_CHANGED)) {
                next_state = STATE_START;
                run_dirsync = PR_TRUE;
                windows_conn_set_agmt_changed(prp->conn);
            } else if (event_occurred(prp, EVENT_TRIGGERING_CRITERIA_MET)) /* change available */
            {
                /* just ignore it and go to sleep */
                protocol_sleep(prp, 0);
            } else if ((e1 = event_occurred(prp, EVENT_WINDOW_CLOSED)) ||
                       event_occurred(prp, EVENT_BACKOFF_EXPIRED)) {
                /* this events - should not occur - log a warning and go to sleep */
                slapi_log_err(SLAPI_LOG_WARNING, windows_repl_plugin_name,
                              "windows_inc_run - %s: "
                              "Event %s should not occur in state %s; going to sleep\n",
                              agmt_get_long_name(prp->agmt),
                              e1 ? event2name(EVENT_WINDOW_CLOSED) : event2name(EVENT_BACKOFF_EXPIRED),
                              state2name(current_state));
                protocol_sleep(prp, 0);
            } else if (event_occurred(prp, EVENT_RUN_DIRSYNC)) /* periodic_dirsync */
            {
                /* just ignore it and go to sleep */
                protocol_sleep(prp, 0);
            } else {
                /* wait until window opens or an event occurs */
                slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                              "windows_inc_run - %s: "
                              "Waiting for update window to open\n",
                              agmt_get_long_name(prp->agmt));
                protocol_sleep(prp, 0);
            }
            break;

        case STATE_WAIT_CHANGES:
            /*
                 * We're in a replication window, but we're waiting for more
                 * changes to accumulate before we actually hook up and send
                 * them.
                 */
            dev_debug("windows_inc_run(STATE_WAIT_CHANGES)");
            if (PROTOCOL_IS_SHUTDOWN(prp)) {
                dev_debug("windows_inc_run(STATE_WAIT_CHANGES): PROTOCOL_IS_SHUTING_DOWN -> end windows_inc_run\n");
                done = 1;
                break;
            } else if (event_occurred(prp, EVENT_REPLICATE_NOW)) {
                dev_debug("windows_inc_run(STATE_WAIT_CHANGES): EVENT_REPLICATE_NOW received -> STATE_READY_TO_ACQUIRE\n");
                next_state = STATE_READY_TO_ACQUIRE;
                wait_change_timer_set = 0;
                /* We also want to run dirsync on a 'replicate now' event */
                run_dirsync = PR_TRUE;
            } else if (event_occurred(prp, EVENT_RUN_DIRSYNC)) {
                dev_debug("windows_inc_run(STATE_WAIT_CHANGES): EVENT_REPLICATE_NOW received -> STATE_READY_TO_ACQUIRE\n");
                next_state = STATE_READY_TO_ACQUIRE;
                wait_change_timer_set = 0;
                run_dirsync = PR_TRUE;

            } else if (event_occurred(prp, EVENT_AGMT_CHANGED)) {
                dev_debug("windows_inc_run(STATE_WAIT_CHANGES): EVENT_AGMT_CHANGED received -> STATE_START\n");
                next_state = STATE_START;
                windows_conn_set_agmt_changed(prp->conn);
                wait_change_timer_set = 0;
                /* We also want to run dirsync on a 'agreement changed' event, because that's how we receive 'send updates now' */
                run_dirsync = PR_TRUE;
            } else if (event_occurred(prp, EVENT_WINDOW_CLOSED)) {
                dev_debug("windows_inc_run(STATE_WAIT_CHANGES): EVENT_WINDOW_CLOSED received -> STATE_WAIT_WINDOW_OPEN\n");
                next_state = STATE_WAIT_WINDOW_OPEN;
                wait_change_timer_set = 0;
            } else if (event_occurred(prp, EVENT_TRIGGERING_CRITERIA_MET)) {
                dev_debug("windows_inc_run(STATE_WAIT_CHANGES): EVENT_TRIGGERING_CRITERIA_MET received -> STATE_READY_TO_ACQUIRE\n");
                next_state = STATE_READY_TO_ACQUIRE;
                wait_change_timer_set = 0;
                /* We want to run dirsync to catch values generated by AD after
                     * it process operations that we send to it (such as GUID values). */
                run_dirsync = PR_TRUE;
            } else if ((e1 = event_occurred(prp, EVENT_WINDOW_OPENED)) ||
                       event_occurred(prp, EVENT_BACKOFF_EXPIRED)) {
                /* this events - should not occur - log a warning and clear the event */
                slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name, "windows_inc_run - %s: "
                                                                       "Event %s should not occur in state %s\n",
                              agmt_get_long_name(prp->agmt),
                              e1 ? event2name(EVENT_WINDOW_OPENED) : event2name(EVENT_BACKOFF_EXPIRED),
                              state2name(current_state));
                wait_change_timer_set = 0;
            } else {
                if (wait_change_timer_set) {
                    /* We are here because our timer expired */
                    dev_debug("windows_inc_run(STATE_WAIT_CHANGES): wait_change_timer_set expired -> STATE_START\n");
                    next_state = STATE_START;
                    run_dirsync = PR_TRUE;
                    wait_change_timer_set = 0;
                } else {
                    /* We are here because the last replication session
                         * finished or aborted.
                         */
                    wait_change_timer_set = 1;
                    protocol_sleep(prp, MAX_WAIT_BETWEEN_SESSIONS);
                }
            }
            break;

        case STATE_READY_TO_ACQUIRE:

            dev_debug("windows_inc_run(STATE_READY_TO_ACQUIRE)");
            if (PROTOCOL_IS_SHUTDOWN(prp)) {
                done = 1;
                break;
            }

            /* ONREPL - at this state we unconditionally acquire the replica
                   ignoring all events. Not sure if this is good */

            rc = windows_acquire_replica(prp, &ruv, (run_dirsync == 0) /* yes, check the consumer RUV for incremental, but not if we're going to dirsync afterwards */);

            slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                          "windows_inc_run - windows_acquire_replica returned %s (%d)\n",
                          acquire2name(rc),
                          rc);

            use_busy_backoff_timer = PR_FALSE; /* default */
            if (rc == ACQUIRE_SUCCESS) {
                next_state = STATE_SENDING_UPDATES;
            } else if (rc == ACQUIRE_REPLICA_BUSY) {
                next_state = STATE_BACKOFF_START;
                use_busy_backoff_timer = PR_TRUE;
            } else if (rc == ACQUIRE_CONSUMER_WAS_UPTODATE) {
                next_state = STATE_WAIT_CHANGES;

            } else if (rc == ACQUIRE_TRANSIENT_ERROR) {
                next_state = STATE_BACKOFF_START;
            } else if (rc == ACQUIRE_FATAL_ERROR) {
                next_state = STATE_STOP_FATAL_ERROR;
            }
            if (rc != ACQUIRE_SUCCESS) {
                int optype, ldaprc;
                windows_conn_get_error(prp->conn, &optype, &ldaprc);
                agmt_set_last_update_status(prp->agmt, ldaprc,
                                            prp->last_acquire_response_code, NULL);
            }

            break;

        case STATE_BACKOFF_START:
            dev_debug("windows_inc_run(STATE_BACKOFF_START)");
            if (PROTOCOL_IS_SHUTDOWN(prp)) {
                done = 1;
                break;
            }
            if (event_occurred(prp, EVENT_REPLICATE_NOW) || event_occurred(prp, EVENT_RUN_DIRSYNC)) {
                next_state = STATE_READY_TO_ACQUIRE;
            } else if (event_occurred(prp, EVENT_AGMT_CHANGED)) {
                next_state = STATE_START;
                run_dirsync = PR_TRUE; /* Also trigger dirsync for the 'send updates now' feature */
                windows_conn_set_agmt_changed(prp->conn);
            } else if (event_occurred(prp, EVENT_WINDOW_CLOSED)) {
                next_state = STATE_WAIT_WINDOW_OPEN;
            } else if (event_occurred(prp, EVENT_TRIGGERING_CRITERIA_MET)) {
                /* consume and ignore */
            } else if ((e1 = event_occurred(prp, EVENT_WINDOW_OPENED)) ||
                       event_occurred(prp, EVENT_BACKOFF_EXPIRED)) {
                /* This should never happen */
                /* this events - should not occur - log a warning and go to sleep */
                slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                              "windows_inc_run - %s: Event %s should not occur in state %s\n",
                              agmt_get_long_name(prp->agmt),
                              e1 ? event2name(EVENT_WINDOW_OPENED) : event2name(EVENT_BACKOFF_EXPIRED),
                              state2name(current_state));
            } else {
                /* Set up the backoff timer to wake us up at the appropriate time */
                /* if previous backoff set up, delete it. */
                if (prp_priv->backoff) {
                    backoff_delete(&prp_priv->backoff);
                }
                if (use_busy_backoff_timer) {
                    /* we received a busy signal from the consumer, wait for a while */
                    if (!busywaittime) {
                        busywaittime = repl5_get_backoff_min(prp);
                    }
                    prp_priv->backoff = backoff_new(BACKOFF_FIXED, busywaittime, busywaittime);
                } else {
                    prp_priv->backoff = backoff_new(BACKOFF_EXPONENTIAL, repl5_get_backoff_min(prp),
                                                    repl5_get_backoff_max(prp));
                }
                next_state = STATE_BACKOFF;
                backoff_reset(prp_priv->backoff, windows_inc_backoff_expired, (void *)prp);
                protocol_sleep(prp, 0);
                use_busy_backoff_timer = PR_FALSE;
            }
            break;

        case STATE_BACKOFF:
            /*
                     * We're in a backoff state.
                     */
            dev_debug("windows_inc_run(STATE_BACKOFF)");
            if (PROTOCOL_IS_SHUTDOWN(prp)) {
                if (prp_priv->backoff)
                    backoff_delete(&prp_priv->backoff);
                done = 1;
                break;
            } else if (event_occurred(prp, EVENT_REPLICATE_NOW) || event_occurred(prp, EVENT_RUN_DIRSYNC)) {
                next_state = STATE_READY_TO_ACQUIRE;
            } else if (event_occurred(prp, EVENT_AGMT_CHANGED)) {
                next_state = STATE_START;
                run_dirsync = PR_TRUE;

                windows_conn_set_agmt_changed(prp->conn);
                /* Destroy the backoff timer, since we won't need it anymore */
                if (prp_priv->backoff)
                    backoff_delete(&prp_priv->backoff);
            } else if (event_occurred(prp, EVENT_WINDOW_CLOSED)) {
                next_state = STATE_WAIT_WINDOW_OPEN;
                /* Destroy the backoff timer, since we won't need it anymore */
                if (prp_priv->backoff)
                    backoff_delete(&prp_priv->backoff);
            } else if (event_occurred(prp, EVENT_BACKOFF_EXPIRED)) {
                rc = windows_acquire_replica(prp, &ruv, 1 /* check RUV for incremental */);
                use_busy_backoff_timer = PR_FALSE;
                if (rc == ACQUIRE_SUCCESS) {
                    next_state = STATE_SENDING_UPDATES;
                } else if (rc == ACQUIRE_REPLICA_BUSY) {
                    next_state = STATE_BACKOFF;
                    use_busy_backoff_timer = PR_TRUE;
                } else if (rc == ACQUIRE_CONSUMER_WAS_UPTODATE) {
                    next_state = STATE_WAIT_CHANGES;
                } else if (rc == ACQUIRE_TRANSIENT_ERROR) {
                    next_state = STATE_BACKOFF;
                } else if (rc == ACQUIRE_FATAL_ERROR) {
                    next_state = STATE_STOP_FATAL_ERROR;
                }

                if (rc != ACQUIRE_SUCCESS) {
                    int optype, ldaprc;
                    windows_conn_get_error(prp->conn, &optype, &ldaprc);
                    agmt_set_last_update_status(prp->agmt, ldaprc,
                                                prp->last_acquire_response_code, NULL);
                }

                /*
                         * We either need to step the backoff timer, or
                         * destroy it if we don't need it anymore.
                         */
                if (STATE_BACKOFF == next_state) {
                    time_t next_fire_time;
                    time_t now;
                    /* Step the backoff timer */
                    time(&now);
                    next_fire_time = backoff_step(prp_priv->backoff);
                    /* And go back to sleep */
                    slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                                  "windows_inc_run - %s: Replication session backing off for %ld seconds\n",
                                  agmt_get_long_name(prp->agmt),
                                  next_fire_time - now);

                    protocol_sleep(prp, 0);
                } else {
                    /* Destroy the backoff timer, since we won't need it anymore */
                    backoff_delete(&prp_priv->backoff);
                }
            } else if (event_occurred(prp, EVENT_TRIGGERING_CRITERIA_MET)) {
                /* changes are available */
                if (prp_priv->backoff == NULL || backoff_expired(prp_priv->backoff, 60)) {
                    /*
                             * Have seen cases that the agmt stuck here forever since
                             * somehow the backoff timer was not in event queue anymore.
                             * If the backoff timer has expired more than 60 seconds,
                             * destroy it.
                             */
                    if (prp_priv->backoff)
                        backoff_delete(&prp_priv->backoff);
                    next_state = STATE_READY_TO_ACQUIRE;
                } else {
                    /* ignore changes and go to sleep */
                    protocol_sleep(prp, 0);
                }
            } else if (event_occurred(prp, EVENT_WINDOW_OPENED)) {
                /* this should never happen - log an error and go to sleep */
                slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name, "windows_inc_run - %s: "
                                                                       "event %s should not occur in state %s; going to sleep\n",
                              agmt_get_long_name(prp->agmt),
                              event2name(EVENT_WINDOW_OPENED), state2name(current_state));
                protocol_sleep(prp, 0);
            }
            break;
        case STATE_SENDING_UPDATES:
            dev_debug("windows_inc_run(STATE_SENDING_UPDATES)");
            agmt_set_update_in_progress(prp->agmt, PR_TRUE);
            num_changes_sent = 0;
            last_start_time = slapi_current_utc_time();
            agmt_set_last_update_start(prp->agmt, last_start_time);
            /*
                     * We've acquired the replica, and are ready to send any
                     * needed updates.
                     */
            if (PROTOCOL_IS_SHUTDOWN(prp)) {
                windows_release_replica(prp);
                done = 1;
                agmt_set_update_in_progress(prp->agmt, PR_FALSE);
                agmt_set_last_update_end(prp->agmt, slapi_current_utc_time());
                /* MAB: I don't find the following status correct. How do we know it has
                           been stopped by an admin and not by a total update request, for instance?
                           In any case, how is this protocol shutdown situation different from all the
                           other ones that are present in this state machine? */
                /* richm: We at least need to let monitors know that the protocol has been
                           shutdown - maybe they can figure out why */
                agmt_set_last_update_status(prp->agmt, 0, 0, "Protocol stopped");
                agmt_update_done(prp->agmt, 0);
                break;
            }

            agmt_set_last_update_status(prp->agmt, 0, 0, "Incremental update started");

            dev_debug("windows_inc_run(STATE_SENDING_UPDATES) -> windows_examine_update_vector");
            rc = windows_examine_update_vector(prp, ruv);
            /*
     * Decide what to do next - proceed with incremental,
     * backoff, or total update
     */
            switch (rc) {
            case EXAMINE_RUV_PARAM_ERROR:
                /* this is really bad - we have NULL prp! */
                next_state = STATE_STOP_FATAL_ERROR;
                break;
            case EXAMINE_RUV_PRISTINE_REPLICA:
                slapi_log_err(SLAPI_LOG_WARNING, windows_repl_plugin_name,
                              "windows_inc_run - %s: Replica has no update vector. It has never been initialized.\n",
                              agmt_get_long_name(prp->agmt));
                next_state = STATE_BACKOFF_START;
                break;
            case EXAMINE_RUV_GENERATION_MISMATCH:
                slapi_log_err(SLAPI_LOG_WARNING, windows_repl_plugin_name,
                              "windows_inc_run - %s: The remote replica has a different database generation ID than "
                              "the local database.  You may have to reinitialize the remote replica, "
                              "or the local replica.\n",
                              agmt_get_long_name(prp->agmt));
                next_state = STATE_BACKOFF_START;
                break;
            case EXAMINE_RUV_REPLICA_TOO_OLD:
                slapi_log_err(SLAPI_LOG_WARNING, windows_repl_plugin_name,
                              "windows_inc_run - %s: Replica update vector is too out of date to bring "
                              "into sync using the incremental protocol. The replica "
                              "must be reinitialized.\n",
                              agmt_get_long_name(prp->agmt));
                next_state = STATE_BACKOFF_START;
                break;
            case EXAMINE_RUV_OK:
                /* update our csn generator state with the consumer's ruv data */
                dev_debug("windows_inc_run(STATE_SENDING_UPDATES) -> windows_examine_update_vector OK");
                replica = prp->replica;
                rc = replica_update_csngen_state(replica, ruv);
                replica = NULL;
                if (rc == CSN_LIMIT_EXCEEDED) /* too much skew */
                {
                    slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                                  "windows_inc_run - %s: Incremental protocol: fatal error - too much time skew between replicas!\n",
                                  agmt_get_long_name(prp->agmt));
                    next_state = STATE_STOP_FATAL_ERROR;
                } else if (rc != 0) /* internal error */
                {
                    slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                                  "windows_inc_run - %s: Incremental protocol: fatal internal error updating the CSN generator!\n",
                                  agmt_get_long_name(prp->agmt));
                    next_state = STATE_STOP_FATAL_ERROR;
                } else {
                    /* call begin incremental update callback */
                    winsync_plugin_call_begin_update_cb(prp->agmt,
                                                        windows_private_get_directory_subtree(prp->agmt),
                                                        windows_private_get_windows_subtree(prp->agmt),
                                                        0 /* is_total == FALSE */);

                    if ((one_way == ONE_WAY_SYNC_DISABLED) || (one_way == ONE_WAY_SYNC_TO_AD)) {
                        rc = send_updates(prp, ruv, &num_changes_sent, 1 /* actually send updates */);
                    } else {
                        /* We call send_updates to fast-forward the RUV
             * without actually sending any updates. */
                        rc = send_updates(prp, ruv, &num_changes_sent, 0 /* don't send updates */);
                    }

                    if (rc == UPDATE_NO_MORE_UPDATES) {
                        dev_debug("windows_inc_run(STATE_SENDING_UPDATES) -> send_updates = UPDATE_NO_MORE_UPDATES -> STATE_WAIT_CHANGES");
                        agmt_set_last_update_status(prp->agmt, 0, 0, "Incremental update succeeded");
                        next_state = STATE_WAIT_CHANGES;
                    } else if (rc == UPDATE_YIELD) {
                        dev_debug("windows_inc_run(STATE_SENDING_UPDATES) -> send_updates = UPDATE_YIELD -> STATE_BACKOFF_START");
                        agmt_set_last_update_status(prp->agmt, 0, 0, "Incremental update succeeded and yielded");
                        next_state = STATE_BACKOFF_START;
                    } else if (rc == UPDATE_TRANSIENT_ERROR) {
                        dev_debug("windows_inc_run(STATE_SENDING_UPDATES) -> send_updates = UPDATE_TRANSIENT_ERROR -> STATE_BACKOFF_START");
                        next_state = STATE_BACKOFF_START;
                    } else if (rc == UPDATE_FATAL_ERROR) {
                        dev_debug("windows_inc_run(STATE_SENDING_UPDATES) -> send_updates = UPDATE_FATAL_ERROR -> STATE_STOP_FATAL_ERROR");
                        next_state = STATE_STOP_FATAL_ERROR;
                    } else if (rc == UPDATE_SCHEDULE_WINDOW_CLOSED) {
                        dev_debug("windows_inc_run(STATE_SENDING_UPDATES) -> send_updates = UPDATE_SCHEDULE_WINDOW_CLOSED -> STATE_WAIT_WINDOW_OPEN");
                        /* ONREPL - I don't think we should check this. We might be
               here because of replicate_now event - so we don't care
               about the schedule */
                        next_state = STATE_WAIT_WINDOW_OPEN;
                        /* ONREPL - do we need to release the replica here ? */
                        windows_conn_disconnect(prp->conn);
                    } else if (rc == UPDATE_CONNECTION_LOST) {
                        dev_debug("windows_inc_run(STATE_SENDING_UPDATES) -> send_updates = UPDATE_CONNECTION_LOST -> STATE_BACKOFF_START");
                        next_state = STATE_BACKOFF_START;
                    } else if (rc == UPDATE_TIMEOUT) {
                        dev_debug("windows_inc_run(STATE_SENDING_UPDATES) -> send_updates = UPDATE_TIMEOUT -> STATE_BACKOFF_START");
                        next_state = STATE_BACKOFF_START;
                    }
                }
                break;
            }

            if (run_dirsync && ((one_way == ONE_WAY_SYNC_DISABLED) || (one_way == ONE_WAY_SYNC_FROM_AD))) {
                /* Don't run dirsync if we encountered
         * an error when sending updates to AD. */
                if (rc == UPDATE_NO_MORE_UPDATES) {
                    windows_dirsync_inc_run(prp);
                    windows_private_save_dirsync_cookie(prp->agmt);
                }
                run_dirsync = PR_FALSE;
            }

            agmt_set_last_update_end(prp->agmt, slapi_current_utc_time());
            agmt_set_update_in_progress(prp->agmt, PR_FALSE);
            agmt_update_done(prp->agmt, 0);
            /* If timed out, close the connection after released the replica */
            windows_release_replica(prp);
            if (rc == UPDATE_TIMEOUT) {
                windows_conn_disconnect(prp->conn);
            }
            /* call end incremental update callback */
            winsync_plugin_call_end_update_cb(prp->agmt,
                                              windows_private_get_directory_subtree(prp->agmt),
                                              windows_private_get_windows_subtree(prp->agmt),
                                              0 /* is_total == FALSE */);

            if (rc == UPDATE_NO_MORE_UPDATES && num_changes_sent > 0) {
                if (pausetime > 0) {
                    /* richm - 20020219 - If we have acquired the consumer, and another supplier has gone
           into backoff waiting for us to release it, we may acquire the replica sooner
           than the other supplier has a chance to, and the other supplier may not be able
           to acquire the consumer for a long time (hours, days?) if this server is
           under a heavy load (see reliab06 et. al. system tests)
           So, this sleep gives the other supplier(s) a chance to acquire the consumer
           replica */
                    long loops = pausetime;
                    /* the while loop is so that we don't just sleep and sleep if an
         event comes in that we should handle immediately (like shutdown) */
                    slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                                  "windows_inc_run - %s: Pausing updates for %ld seconds to allow other suppliers to update consumer\n",
                                  agmt_get_long_name(prp->agmt), pausetime);
                    while (loops-- && !(PROTOCOL_IS_SHUTDOWN(prp))) {
                        DS_Sleep(PR_SecondsToInterval(1));
                    }
                } else if (num_changes_sent > 10) {
                    /* wait for consumer to write its ruv if the replication was busy */
                    /* When asked, consumer sends its ruv in cache to the supplier. */
                    /* DS_Sleep ( PR_SecondsToInterval(1) ); */
                }
            }

            break;
        case STATE_STOP_FATAL_ERROR:
            /*
     * We encountered some sort of a fatal error. Suspend.
     */
            /* XXXggood update state in replica */
            agmt_set_last_update_status(prp->agmt, -1, 0, "Incremental update has failed and requires administrator action");
            dev_debug("windows_inc_run(STATE_STOP_FATAL_ERROR)");
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "windows_inc_run - %s: Incremental update failed and requires administrator action\n",
                          agmt_get_long_name(prp->agmt));
            next_state = STATE_STOP_FATAL_ERROR_PART2;
            break;
        case STATE_STOP_FATAL_ERROR_PART2:
            if (PROTOCOL_IS_SHUTDOWN(prp)) {
                done = 1;
                break;
            }

            /* MAB: This state is the FATAL state where we are supposed to get
       as a result of a FATAL error on send_updates. But, as bug
       states, send_updates was always returning TRANSIENT errors and never
       FATAL... In other words, this code has never been tested before...

       As of 01/16/01, this piece of code was in a very dangerous state. In particular,
        1) it does not catch any events
        2) it is a terminal state (once reached it never transitions to a different state)

       Both things combined make this state to become a consuming infinite loop
       that is useless after all (we are in a fatal place requiring manual admin jobs */

            /* MAB: The following lines fix problem number 1 above... When the code gets
       into this state, it should only get a chance to get out of it by an
       EVENT_AGMT_CHANGED event... All other events should be ignored */
            else if (event_occurred(prp, EVENT_AGMT_CHANGED)) {
                dev_debug("windows_inc_run(STATE_STOP_FATAL_ERROR): EVENT_AGMT_CHANGED received\n");
                /* Chance to recover for the EVENT_AGMT_CHANGED event.
           This is not mandatory, but fixes problem 2 above */
                next_state = STATE_STOP_NORMAL_TERMINATION;
            } else {
                dev_debug("windows_inc_run(STATE_STOP_FATAL_ERROR): Event received. Clearing it\n");
                reset_events(prp);
            }

            protocol_sleep(prp, 0);
            break;

        case STATE_STOP_NORMAL_TERMINATION:
            /*
     * We encountered some sort of a fatal error. Return.
     */
            /* XXXggood update state in replica */
            dev_debug("windows_inc_run(STATE_STOP_NORMAL_TERMINATION)");
            done = 1;
            break;
        }

        slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                      "windows_inc_run - %s: State: %s -> %s\n",
                      agmt_get_long_name(prp->agmt),
                      state2name(current_state), state2name(next_state));


        current_state = next_state;
    } while (!done);
    /* remove_protocol_callbacks(prp); */
    prp->stopped = 1;
    /* Cancel any linger timer that might be in effect... */
    windows_conn_cancel_linger(prp->conn);
    /* ... and disconnect, if currently connected */
    windows_conn_disconnect(prp->conn);
    ruv_destroy(&ruv);
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_inc_run\n");
}

/*
 * Go to sleep until awakened.
 */
static void
protocol_sleep(Private_Repl_Protocol *prp, int32_t duration)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> protocol_sleep\n");
    PR_ASSERT(NULL != prp);
    pthread_mutex_lock(&(prp->lock));
    /* we should not go to sleep if there are events available to be processed.
       Otherwise, we can miss the event that suppose to wake us up */
    if (prp->eventbits == 0) {
        if (duration > 0) {
            struct timespec current_time = {0};
            /* get the current monotonic time and add our interval */
            clock_gettime(CLOCK_MONOTONIC, &current_time);
            current_time.tv_sec += duration;
            pthread_cond_timedwait(&(prp->cvar), &(prp->lock), &current_time);
        } else {
            pthread_cond_wait(&(prp->cvar), &(prp->lock));
        }
    } else {
        slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                      "protocol_sleep - %s: Can't go to sleep: event bits - %x\n",
                      agmt_get_long_name(prp->agmt), prp->eventbits);
    }
    pthread_mutex_unlock(&(prp->lock));
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= protocol_sleep\n");
}


/*
 * Notify the protocol about some event. Signal the condition
 * variable in case the protocol is sleeping. Multiple occurences
 * of a single event type are not remembered (e.g. no stack
 * of events is maintained).
 */
static void
event_notify(Private_Repl_Protocol *prp, PRUint32 event)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> event_notify\n");
    PR_ASSERT(NULL != prp);
    pthread_mutex_lock(&(prp->lock));
    prp->eventbits |= event;
    pthread_cond_signal(&(prp->cvar));
    pthread_mutex_unlock(&(prp->lock));
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= event_notify\n");
}


/*
 * Test to see if an event occurred. The event is cleared when
 * read.
 */
static PRUint32
event_occurred(Private_Repl_Protocol *prp, PRUint32 event)
{
    PRUint32 return_value;

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> event_occurred\n");

    PR_ASSERT(NULL != prp);
    pthread_mutex_lock(&(prp->lock));
    return_value = (prp->eventbits & event);
    prp->eventbits &= ~event; /* Clear event */
    pthread_mutex_unlock(&(prp->lock));
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= event_occurred\n");
    return return_value;
}

static void
reset_events(Private_Repl_Protocol *prp)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> reset_events\n");
    PR_ASSERT(NULL != prp);
    pthread_mutex_lock(&(prp->lock));
    prp->eventbits = 0;
    pthread_mutex_unlock(&(prp->lock));
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= reset_events\n");
}


static PRBool
is_dummy_operation(const slapi_operation_parameters *op)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> is_dummy_operation\n");
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= is_dummy_operation\n");
    return (strcmp(op->target_address.uniqueid, START_ITERATION_ENTRY_UNIQUEID) == 0);
}


void
w_cl5_operation_parameters_done(struct slapi_operation_parameters *sop)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> w_cl5_operation_parameters_done\n");
    if (sop != NULL) {
        switch (sop->operation_type) {
        case SLAPI_OPERATION_BIND:
            slapi_ch_free((void **)&(sop->p.p_bind.bind_saslmechanism));
            if (sop->p.p_bind.bind_creds)
                ber_bvecfree((struct berval **)&(sop->p.p_bind.bind_creds));
            if (sop->p.p_bind.bind_ret_saslcreds)
                ber_bvecfree((struct berval **)&(sop->p.p_bind.bind_ret_saslcreds));
            sop->p.p_bind.bind_creds = NULL;
            sop->p.p_bind.bind_ret_saslcreds = NULL;
            break;
        case SLAPI_OPERATION_COMPARE:
            ava_done((struct ava *)&(sop->p.p_compare.compare_ava));
            break;
        case SLAPI_OPERATION_SEARCH:
            slapi_ch_free((void **)&(sop->p.p_search.search_strfilter));
            charray_free(sop->p.p_search.search_attrs);
            slapi_filter_free(sop->p.p_search.search_filter, 1);
            break;
        case SLAPI_OPERATION_MODRDN:
            sop->p.p_modrdn.modrdn_deloldrdn = 0;
            break;
        case SLAPI_OPERATION_EXTENDED:
            slapi_ch_free((void **)&(sop->p.p_extended.exop_oid));
            if (sop->p.p_extended.exop_value)
                ber_bvecfree((struct berval **)&(sop->p.p_extended.exop_value));
            sop->p.p_extended.exop_value = NULL;
            break;
        default:
            break;
        }
    }
    operation_parameters_done(sop);
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= w_cl5_operation_parameters_done\n");
}


/*
 * Send a set of updates to the replica.  Assumes that (1) the replica
 * has already been acquired, (2) that the consumer's update vector has
 * been checked and (3) that it's ok to send incremental updates.
 * Returns:
 * UPDATE_NO_MORE_UPDATES - all updates were sent succussfully
 * UPDATE_TRANSIENT_ERROR - some non-permanent error occurred. Try again later.
 * UPDATE_FATAL_ERROR - some bad, permanent error occurred.
 * UPDATE_SCHEDULE_WINDOW_CLOSED - the schedule window closed on us.
 */
static int
send_updates(Private_Repl_Protocol *prp, RUV *remote_update_vector, PRUint32 *num_changes_sent, int do_send)
{
    CL5Entry entry;
    slapi_operation_parameters op;
    int return_value = UPDATE_NO_MORE_UPDATES;
    int rc;
    int set_mincsn = 0;
    CL5ReplayIterator *changelog_iterator = NULL;
    RUV *current_ruv = ruv_dup(remote_update_vector);
    CSN *mincsn = NULL;

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> send_updates\n");

    *num_changes_sent = 0;

    /* Check if the min csn is set in our RUV to see if we need to set it below. */
    ruv_get_min_csn(current_ruv, &mincsn);
    if (!mincsn) {
        set_mincsn = 1;
    } else {
        csn_free(&mincsn);
    }

    /*
     * Iterate over the changelog. Retrieve each update,
     * construct an appropriate LDAP operation,
     * attaching the CSN, and send the change.
     */


    rc = cl5CreateReplayIteratorEx(prp, remote_update_vector, &changelog_iterator, agmt_get_consumerRID(prp->agmt));
    if (CL5_SUCCESS != rc) {
        switch (rc) {
        case CL5_BAD_DATA: /* invalid parameter passed to the function */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: Invalid parameter passed to cl5CreateReplayIterator\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_FATAL_ERROR;
            break;
        case CL5_BAD_FORMAT: /* db data has unexpected format */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: Unexpected format encountered in changelog database\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_FATAL_ERROR;
            break;
        case CL5_BAD_STATE: /* changelog is in an incorrect state for attempted operation */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: Changelog database was in an incorrect state\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_FATAL_ERROR;
            break;
        case CL5_BAD_DBVERSION: /* changelog has invalid dbversion */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: Incorrect dbversion found in changelog database\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_FATAL_ERROR;
            break;
        case CL5_DB_ERROR: /* database error */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: A changelog database error was encountered\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_FATAL_ERROR;
            break;
        case CL5_NOTFOUND: /* we have no changes to send */
            slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                          "%s: No changes to send\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_NO_MORE_UPDATES;
            break;
        case CL5_MEMORY_ERROR: /* memory allocation failed */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: Memory allocation error occurred\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_FATAL_ERROR;
            break;
        case CL5_SYSTEM_ERROR: /* NSPR error occurred: use PR_GetError for furhter info */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: An NSPR error (%d) occurred\n",
                          agmt_get_long_name(prp->agmt), PR_GetError());
            return_value = UPDATE_TRANSIENT_ERROR;
            break;
        case CL5_CSN_ERROR: /* CSN API failed */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: A CSN API failure was encountered\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_TRANSIENT_ERROR;
            break;
        case CL5_RUV_ERROR: /* RUV API failed */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: An RUV API failure occurred\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_TRANSIENT_ERROR;
            break;
        case CL5_OBJSET_ERROR: /* namedobjset api failed */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: A namedobject API failure occurred\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_TRANSIENT_ERROR;
            break;
        case CL5_PURGED_DATA: /* requested data has been purged */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: Data required to update replica has been purged. "
                          "The replica must be reinitialized.\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_FATAL_ERROR;
            break;
        case CL5_MISSING_DATA: /* data should be in the changelog, but is missing */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: Missing data encountered\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_FATAL_ERROR;
            break;
        case CL5_UNKNOWN_ERROR: /* unclassified error */
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: An unknown error was ecountered\n",
                          agmt_get_long_name(prp->agmt));
            return_value = UPDATE_TRANSIENT_ERROR;
            break;
        default:
            slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                          "send_updates - %s: An unknown error (%d) occurred "
                          "(cl5CreateReplayIterator)\n",
                          agmt_get_long_name(prp->agmt), rc);
            return_value = UPDATE_TRANSIENT_ERROR;
        }
    } else {
        int finished = 0;
        ConnResult replay_crc;
        char csn_str[CSN_STRSIZE];
        Replica *replica = prp->replica;

        memset((void *)&op, 0, sizeof(op));
        entry.op = &op;
        do {
            int mark_record_done = 0;
            w_cl5_operation_parameters_done(entry.op);
            memset((void *)entry.op, 0, sizeof(op));
            rc = cl5GetNextOperationToReplay(changelog_iterator, &entry);
            switch (rc) {
            case CL5_SUCCESS:
                /* check that we don't return dummy entries */
                if (is_dummy_operation(entry.op)) {
                    slapi_log_err(SLAPI_LOG_WARNING, windows_repl_plugin_name,
                                  "send_updates - %s: changelog iteration code returned a dummy entry with csn %s, "
                                  "skipping ...\n",
                                  agmt_get_long_name(prp->agmt), csn_as_string(entry.op->csn, PR_FALSE, csn_str));
                    continue;
                }
                /* This is where the work actually happens: */
                if (do_send) {
                    replay_crc = windows_replay_update(prp, entry.op);
                } else {
                    /* Skip sending the updates and just set a success code. */
                    replay_crc = CONN_OPERATION_SUCCESS;
                }
                if (CONN_OPERATION_SUCCESS != replay_crc) {
                    int operation, error;
                    windows_conn_get_error(prp->conn, &operation, &error);
                    csn_as_string(entry.op->csn, PR_FALSE, csn_str);
                    /* Figure out what to do next */
                    if (CONN_OPERATION_FAILED == replay_crc) {
                        /* Map ldap error code to return value */
                        if (!windows_ignore_error_and_keep_going(error)) {
                            return_value = UPDATE_TRANSIENT_ERROR;
                            finished = 1;
                        } else {
                            agmt_inc_last_update_changecount(prp->agmt, csn_get_replicaid(entry.op->csn), 1 /*skipped*/);
                            mark_record_done = 1;
                        }
                        slapi_log_err(finished ? SLAPI_LOG_WARNING : slapi_log_urp,
                                      windows_repl_plugin_name,
                                      "send_updates - %s: Consumer failed to replay change (uniqueid %s, CSN %s): %s. %s.\n",
                                      agmt_get_long_name(prp->agmt),
                                      entry.op->target_address.uniqueid, csn_str,
                                      ldap_err2string(error),
                                      finished ? "Will retry later" : "Skipping");
                    } else if (CONN_NOT_CONNECTED == replay_crc) {
                        /* We lost the connection - enter backoff state */

                        return_value = UPDATE_TRANSIENT_ERROR;
                        finished = 1;
                        slapi_log_err(SLAPI_LOG_WARNING, windows_repl_plugin_name,
                                      "send_updates - %s: Consumer failed to replay change (uniqueid %s, CSN %s): "
                                      "%s. Will retry later.\n",
                                      agmt_get_long_name(prp->agmt),
                                      entry.op->target_address.uniqueid, csn_str,
                                      error ? ldap_err2string(error) : "Connection lost");
                    } else if (CONN_TIMEOUT == replay_crc) {
                        return_value = UPDATE_TIMEOUT;
                        finished = 1;
                        slapi_log_err(SLAPI_LOG_WARNING, windows_repl_plugin_name,
                                      "send_updates - %s: Consumer timed out to replay change (uniqueid %s, CSN %s): "
                                      "%s.\n",
                                      agmt_get_long_name(prp->agmt),
                                      entry.op->target_address.uniqueid, csn_str,
                                      error ? ldap_err2string(error) : "Timeout");
                    } else if (CONN_LOCAL_ERROR == replay_crc) {
                        /*
                         * Something bad happened on the local server - enter
                         * backoff state.
                         */
                        return_value = UPDATE_TRANSIENT_ERROR;
                        finished = 1;
                        slapi_log_err(SLAPI_LOG_WARNING, windows_repl_plugin_name,
                                      "send_updates - %s: Failed to replay change (uniqueid %s, CSN %s): "
                                      "Local error. Will retry later.\n",
                                      agmt_get_long_name(prp->agmt),
                                      entry.op->target_address.uniqueid, csn_str);
                    }

                } else {
                    /* Positive response received */
                    (*num_changes_sent)++;
                    agmt_inc_last_update_changecount(prp->agmt, csn_get_replicaid(entry.op->csn), 0 /*replayed*/);
                    mark_record_done = 1;
                }
                if (mark_record_done) {
                    /* If this is the very first change being sent,
                     * it's possible that we haven't set a min csn
                     * in the RUV yet.  This is possible because we
                     * simply copy the supplier RUV during the total
                     * update process.  The supplier RUV will not have
                     * a min or max csn set if no changes have ever
                     * been written to it's changelog.  We need to set
                     * the min csn for the consumer here to prevent
                     * problems with further sync operations. */
                    if (set_mincsn) {
                        ruv_set_min_csn(current_ruv, entry.op->csn, NULL);
                        set_mincsn = 0;
                    }

                    /* Bring the consumers (AD) RUV up to date.
                     * This sets the max csn. */
                    ruv_force_csn_update(current_ruv, entry.op->csn);
                }
                break;
            case CL5_BAD_DATA:
                slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                              "send_updates - %s: Invalid parameter passed to cl5GetNextOperationToReplay\n",
                              agmt_get_long_name(prp->agmt));
                return_value = UPDATE_FATAL_ERROR;
                finished = 1;
                break;
            case CL5_NOTFOUND:
                slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                              "send_updates - %s: No more updates to send (cl5GetNextOperationToReplay)\n",
                              agmt_get_long_name(prp->agmt));
                return_value = UPDATE_NO_MORE_UPDATES;
                finished = 1;
                break;
            case CL5_DB_ERROR:
                slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                              "send_updates - %s: A database error occurred (cl5GetNextOperationToReplay)\n",
                              agmt_get_long_name(prp->agmt));
                return_value = UPDATE_FATAL_ERROR;
                finished = 1;
                break;
            case CL5_BAD_FORMAT:
                slapi_log_err(SLAPI_LOG_WARNING, windows_repl_plugin_name,
                              "send_updates - %s: A malformed changelog entry was encountered (cl5GetNextOperationToReplay)\n",
                              agmt_get_long_name(prp->agmt));
                break;
            case CL5_MEMORY_ERROR:
                slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                              "send_updates - %s: A memory allocation error occurred (cl5GetNextOperationToRepla)\n",
                              agmt_get_long_name(prp->agmt));
                return_value = UPDATE_FATAL_ERROR;
                break;
            default:
                slapi_log_err(SLAPI_LOG_ERR, windows_repl_plugin_name,
                              "send_updates - %s: Unknown error code (%d) returned from cl5GetNextOperationToReplay\n",
                              agmt_get_long_name(prp->agmt), rc);
                return_value = UPDATE_TRANSIENT_ERROR;
                break;
            }
            /* Check for protocol shutdown */
            if (prp->terminate) {
                return_value = UPDATE_NO_MORE_UPDATES;
                finished = 1;
            }
            if (*num_changes_sent >= MAX_CHANGES_PER_SESSION) {
                return_value = UPDATE_YIELD;
                finished = 1;
            }
        } while (!finished);
        w_cl5_operation_parameters_done(entry.op);
        cl5DestroyReplayIterator(&changelog_iterator, replica);
    }
    /* Save the RUV that we successfully replayed, this ensures that next time we start off at the next changelog record */
    if (current_ruv) {
        agmt_set_consumer_ruv(prp->agmt, current_ruv);
        ruv_destroy(&current_ruv);
    }
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= send_updates\n");
    return return_value;
}

/*
 * XXXggood this should probably be in the superclass, since the full update
 * protocol is going to need it too.
 */
static int
windows_inc_stop(Private_Repl_Protocol *prp)
{
    int return_value;
    PRIntervalTime start, maxwait, now;
    int seconds = 1200;

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_inc_stop\n");

    maxwait = PR_SecondsToInterval(seconds);
    prp->terminate = 1;
    event_notify(prp, EVENT_PROTOCOL_SHUTDOWN);
    start = PR_IntervalNow();
    now = start;
    while (!prp->stopped && ((now - start) < maxwait)) {
        DS_Sleep(PR_SecondsToInterval(1));
        now = PR_IntervalNow();
    }
    if (!prp->stopped) {
        /* Isn't listening. Do something drastic. */
        return_value = -1;
        slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                      "windows_inc_stop - %s: Protocol does not stop after %d seconds\n",
                      agmt_get_long_name(prp->agmt), seconds);
    } else {
        return_value = 0;
        slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                      "windows_inc_stop - %s: Protocol stopped after %d seconds\n",
                      agmt_get_long_name(prp->agmt),
                      PR_IntervalToSeconds(now - start));
    }
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_inc_stop\n");
    return return_value;
}

static int
windows_inc_status(Private_Repl_Protocol *prp __attribute__((unused)))
{
    int return_value = 0;

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_inc_status\n");
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_inc_status\n");

    return return_value;
}

static void
windows_inc_notify_update(Private_Repl_Protocol *prp)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_inc_notify_update\n");
    event_notify(prp, EVENT_TRIGGERING_CRITERIA_MET);
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_inc_notify_update\n");
}


static void
windows_inc_update_now(Private_Repl_Protocol *prp)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_inc_update_now\n");
    event_notify(prp, EVENT_REPLICATE_NOW);
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_inc_update_now\n");
}


static void
windows_inc_notify_agmt_changed(Private_Repl_Protocol *prp)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_inc_notify_agmt_changed\n");
    event_notify(prp, EVENT_AGMT_CHANGED);
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_inc_notify_agmt_changed\n");
}

static void
windows_inc_notify_window_opened(Private_Repl_Protocol *prp)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_inc_notify_window_opened\n");
    event_notify(prp, EVENT_WINDOW_OPENED);
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_inc_notify_window_opened\n");
}

static void
windows_inc_notify_window_closed(Private_Repl_Protocol *prp)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_inc_notify_window_closed\n");
    event_notify(prp, EVENT_WINDOW_CLOSED);
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_inc_notify_window_closed\n");
}


Private_Repl_Protocol *
Windows_Inc_Protocol_new(Repl_Protocol *rp)
{
    windows_inc_private *rip = NULL;
    Private_Repl_Protocol *prp = (Private_Repl_Protocol *)slapi_ch_calloc(1, sizeof(Private_Repl_Protocol));
    pthread_condattr_t cattr;

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> Windows_Inc_Protocol_new\n");

    prp->delete = windows_inc_delete;
    prp->run = windows_inc_run;
    prp->stop = windows_inc_stop;
    prp->status = windows_inc_status;
    prp->notify_update = windows_inc_notify_update;
    prp->notify_agmt_changed = windows_inc_notify_agmt_changed;
    prp->notify_window_opened = windows_inc_notify_window_opened;
    prp->notify_window_closed = windows_inc_notify_window_closed;
    prp->update_now = windows_inc_update_now;
    prp->replica = prot_get_replica(rp);
    if (pthread_mutex_init(&(prp->lock), NULL) != 0) {
        goto loser;
    }
    if (pthread_condattr_init(&cattr) != 0) {
        goto loser;
    }
    if (pthread_condattr_setclock(&cattr, CLOCK_MONOTONIC) != 0) {
        goto loser;
    }
    if (pthread_cond_init(&(prp->cvar), &cattr) != 0) {
        goto loser;
    }
    pthread_condattr_destroy(&cattr); /* no longer needed */
    prp->stopped = 0;
    prp->terminate = 0;
    prp->eventbits = 0;
    prp->conn = prot_get_connection(rp);
    prp->agmt = prot_get_agreement(rp);
    prp->last_acquire_response_code = NSDS50_REPL_REPLICA_READY;
    rip = (void *)slapi_ch_malloc(sizeof(windows_inc_private));
    rip->ruv = NULL;
    rip->backoff = NULL;
    rip->rp = rp;
    prp->private = (void *)rip;
    prp->replica_acquired = PR_FALSE;

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= Windows_Inc_Protocol_new\n");

    return prp;

loser:
    windows_inc_delete(&prp);
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= Windows_Inc_Protocol_new (loser)\n");
    return NULL;
}


static void
windows_inc_backoff_expired(time_t timer_fire_time __attribute__((unused)), void *arg)
{
    Private_Repl_Protocol *prp = (Private_Repl_Protocol *)arg;

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_inc_backoff_expired\n");

    PR_ASSERT(NULL != prp);
    event_notify(prp, EVENT_BACKOFF_EXPIRED);

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_inc_backoff_expired\n");
}


/*
 * Examine the update vector and determine our course of action.
 * There are 3 different possibilities, plus a catch-all error:
 * 1 - no update vector (ruv is NULL). The consumer's replica is
 *     pristine, so it needs to be initialized. Return
 *     EXAMINE_RUV_PRISTINE_REPLICA.
 * 2 - ruv is present, but its database generation ID doesn't
 *     match the local generation ID. This means that either
 *     the local replica must be reinitialized from the remote
 *     replica or vice-versa. Return
 *     EXAMINE_RUV_GENERATION_MISMATCH.
 * 3 - ruv is present, and we have all updates needed to bring
 *     the replica up to date using the incremental protocol.
 *     return EXAMINE_RUV_OK.
 * 4 - parameter error. Return EXAMINE_RUV_PARAM_ERROR
 */
static int
windows_examine_update_vector(Private_Repl_Protocol *prp, RUV *remote_ruv)
{
    int return_value;

    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> windows_examine_update_vector\n");

    PR_ASSERT(NULL != prp);
    if (NULL == prp) {
        return_value = EXAMINE_RUV_PARAM_ERROR;
    } else if (NULL == remote_ruv) {
        return_value = EXAMINE_RUV_PRISTINE_REPLICA;
    } else {
        char *local_gen = NULL;
        char *remote_gen = ruv_get_replica_generation(remote_ruv);
        Object *local_ruv_obj;
        RUV *local_ruv;

        PR_ASSERT(NULL != prp->replica);
        local_ruv_obj = replica_get_ruv(prp->replica);
        if (NULL != local_ruv_obj) {
            local_ruv = (RUV *)object_get_data(local_ruv_obj);
            PR_ASSERT(local_ruv);
            local_gen = ruv_get_replica_generation(local_ruv);
            object_release(local_ruv_obj);
        }
        if (NULL == remote_gen || NULL == local_gen || strcmp(remote_gen, local_gen) != 0) {
            return_value = EXAMINE_RUV_GENERATION_MISMATCH;
        } else {
            return_value = EXAMINE_RUV_OK;
        }
        slapi_ch_free((void **)&remote_gen);
        slapi_ch_free((void **)&local_gen);
    }
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= windows_examine_update_vector\n");
    return return_value;
}


/* this function converts an aquisition code to a string - for debug output */
static const char *
acquire2name(int code)
{
    switch (code) {
    case ACQUIRE_SUCCESS:
        return "success";
    case ACQUIRE_REPLICA_BUSY:
        return "replica_busy";
    case ACQUIRE_FATAL_ERROR:
        return "fatal_error";
    case ACQUIRE_CONSUMER_WAS_UPTODATE:
        return "consumer_was_uptodate";
    case ACQUIRE_TRANSIENT_ERROR:
        return "transient_error";
    default:
        return "invalid_code";
    }
}


/* this function converts a state to its name - for debug output */
static const char *
state2name(int state)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> state2name\n");
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= state2name\n");
    switch (state) {
    case STATE_START:
        return "start";
    case STATE_WAIT_WINDOW_OPEN:
        return "wait_for_window_to_open";
    case STATE_WAIT_CHANGES:
        return "wait_for_changes";
    case STATE_READY_TO_ACQUIRE:
        return "ready_to_acquire_replica";
    case STATE_BACKOFF_START:
        return "start_backoff";
    case STATE_BACKOFF:
        return "backoff";
    case STATE_SENDING_UPDATES:
        return "sending_updates";
    case STATE_STOP_FATAL_ERROR:
        return "stop_fatal_error";
    case STATE_STOP_FATAL_ERROR_PART2:
        return "stop_fatal_error";
    case STATE_STOP_NORMAL_TERMINATION:
        return "stop_normal_termination";
    default:
        return "invalid_state";
    }
}

/* this function convert s an event to its name - for debug output */
static const char *
event2name(int event)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> event2name\n");
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= event2name\n");
    switch (event) {
    case EVENT_WINDOW_OPENED:
        return "update_window_opened";
    case EVENT_WINDOW_CLOSED:
        return "update_window_closed";
    case EVENT_TRIGGERING_CRITERIA_MET:
        return "data_modified";
    case EVENT_BACKOFF_EXPIRED:
        return "backoff_timer_expired";
    case EVENT_REPLICATE_NOW:
        return "replicate_now";
    case EVENT_PROTOCOL_SHUTDOWN:
        return "protocol_shutdown";
    case EVENT_AGMT_CHANGED:
        return "agreement_changed";
    case EVENT_RUN_DIRSYNC:
        return "run_dirsync";
    default:
        return "invalid_event";
    }
}


static void
periodic_dirsync(time_t when __attribute__((unused)), void *arg)
{
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "=> periodic_dirsync\n");

    slapi_log_err(SLAPI_LOG_REPL, windows_repl_plugin_name,
                  "periodic_dirsync - Running Dirsync \n");

    event_notify((Private_Repl_Protocol *)arg, EVENT_RUN_DIRSYNC);
    slapi_log_err(SLAPI_LOG_TRACE, windows_repl_plugin_name, "<= periodic_dirsync\n");
}