servers/slapd/connection.c

/*	$NetBSD: connection.c,v 1.3 2021/08/14 16:14:58 christos Exp $	*/

/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
 *
 * Copyright 1998-2021 The OpenLDAP Foundation.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted only as authorized by the OpenLDAP
 * Public License.
 *
 * A copy of this license is available in the file LICENSE in the
 * top-level directory of the distribution or, alternatively, at
 * <http://www.OpenLDAP.org/license.html>.
 */
/* Portions Copyright (c) 1995 Regents of the University of Michigan.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that this notice is preserved and that due credit is given
 * to the University of Michigan at Ann Arbor. The name of the University
 * may not be used to endorse or promote products derived from this
 * software without specific prior written permission. This software
 * is provided ``as is'' without express or implied warranty.
 */

#include <sys/cdefs.h>
__RCSID("$NetBSD: connection.c,v 1.3 2021/08/14 16:14:58 christos Exp $");

#include "portable.h"

#include <stdio.h>
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif

#include <ac/socket.h>
#include <ac/errno.h>
#include <ac/string.h>
#include <ac/time.h>
#include <ac/unistd.h>

#include "lutil.h"
#include "slap.h"

#ifdef LDAP_CONNECTIONLESS
#include "../../libraries/liblber/lber-int.h"	/* ber_int_sb_read() */
#endif

#ifdef LDAP_SLAPI
#include "slapi/slapi.h"
#endif

static Connection *connections = NULL;

static ldap_pvt_thread_mutex_t conn_nextid_mutex;
static unsigned long conn_nextid = SLAPD_SYNC_SYNCCONN_OFFSET;

static const char conn_lost_str[] = "connection lost";

const char *
connection_state2str( int state )
{
	switch( state ) {
	case SLAP_C_INVALID:	return "!";
	case SLAP_C_INACTIVE:	return "|";
	case SLAP_C_CLOSING:	return "C";
	case SLAP_C_ACTIVE:		return "";
	case SLAP_C_BINDING:	return "B";
	case SLAP_C_CLIENT:		return "L";
	}

	return "?";
}

static Connection* connection_get( ber_socket_t s );

typedef struct conn_readinfo {
	Operation *op;
	ldap_pvt_thread_start_t *func;
	void *arg;
	void *ctx;
	int nullop;
} conn_readinfo;

static int connection_input( Connection *c, conn_readinfo *cri );
static void connection_close( Connection *c );

static int connection_op_activate( Operation *op );
static void connection_op_queue( Operation *op );
static int connection_resched( Connection *conn );
static void connection_abandon( Connection *conn );
static void connection_destroy( Connection *c );

static ldap_pvt_thread_start_t connection_operation;

/*
 * Initialize connection management infrastructure.
 */
int connections_init(void)
{
	int i;

	assert( connections == NULL );

	if( connections != NULL) {
		Debug( LDAP_DEBUG_ANY, "connections_init: already initialized.\n" );
		return -1;
	}

	/* should check return of every call */
	ldap_pvt_thread_mutex_init( &conn_nextid_mutex );

	connections = (Connection *) ch_calloc( dtblsize, sizeof(Connection) );

	if( connections == NULL ) {
		Debug( LDAP_DEBUG_ANY, "connections_init: "
			"allocation (%d*%ld) of connection array failed\n",
			dtblsize, (long) sizeof(Connection) );
		return -1;
	}

	for (i=0; i<dtblsize; i++) {
		connections[i].c_conn_idx = i;
		ldap_pvt_thread_mutex_init( &connections[i].c_mutex );
		ldap_pvt_thread_mutex_init( &connections[i].c_write1_mutex );
		ldap_pvt_thread_cond_init( &connections[i].c_write1_cv );
	}


	/*
	 * per entry initialization of the Connection array initialization
	 * will be done by connection_init()
	 */

	return 0;
}

/*
 * Destroy connection management infrastructure.
 */

int connections_destroy(void)
{
	ber_socket_t i;

	/* should check return of every call */

	if( connections == NULL) {
		Debug( LDAP_DEBUG_ANY, "connections_destroy: nothing to destroy.\n" );
		return -1;
	}

	for ( i = 0; i < dtblsize; i++ ) {
		ldap_pvt_thread_mutex_destroy( &connections[i].c_mutex );
		ldap_pvt_thread_mutex_destroy( &connections[i].c_write1_mutex );
		ldap_pvt_thread_cond_destroy( &connections[i].c_write1_cv );
		if( connections[i].c_sb ) {
			ber_sockbuf_free( connections[i].c_sb );
#ifdef LDAP_SLAPI
			if ( slapi_plugins_used ) {
				slapi_int_free_object_extensions( SLAPI_X_EXT_CONNECTION,
					&connections[i] );
			}
#endif
		}
	}

	free( connections );
	connections = NULL;

	ldap_pvt_thread_mutex_destroy( &conn_nextid_mutex );
	return 0;
}

/*
 * shutdown all connections
 */
int connections_shutdown(void)
{
	ber_socket_t i;

	for ( i = 0; i < dtblsize; i++ ) {
		ldap_pvt_thread_mutex_lock( &connections[i].c_mutex );
		if( connections[i].c_conn_state > SLAP_C_INVALID ) {

			/* give persistent clients a chance to cleanup */
			if( connections[i].c_conn_state == SLAP_C_CLIENT ) {
				ldap_pvt_thread_pool_submit( &connection_pool,
				connections[i].c_clientfunc, connections[i].c_clientarg );
			} else {
				/* c_mutex is locked */
				connection_closing( &connections[i], "slapd shutdown" );
				connection_close( &connections[i] );
			}
		}
		ldap_pvt_thread_mutex_unlock( &connections[i].c_mutex );
	}

	return 0;
}

/*
 * Timeout idle connections.
 */
int connections_timeout_idle(time_t now)
{
	int i = 0;
	ber_socket_t connindex;
	Connection* c;

	for( c = connection_first( &connindex );
		c != NULL;
		c = connection_next( c, &connindex ) )
	{
		/* Don't timeout a slow-running request or a persistent
		 * outbound connection.
		 */
		if(( c->c_n_ops_executing && !c->c_writewaiter)
			|| c->c_conn_state == SLAP_C_CLIENT ) {
			continue;
		}

		if( global_idletimeout &&
			difftime( c->c_activitytime+global_idletimeout, now) < 0 ) {
			/* close it */
			connection_closing( c, "idletimeout" );
			connection_close( c );
			i++;
			continue;
		}
	}
	connection_done( c );

	return i;
}

/* Drop all client connections */
void connections_drop()
{
	Connection* c;
	ber_socket_t connindex;

	for( c = connection_first( &connindex );
		c != NULL;
		c = connection_next( c, &connindex ) )
	{
		/* Don't close a slow-running request or a persistent
		 * outbound connection.
		 */
		if(( c->c_n_ops_executing && !c->c_writewaiter)
			|| c->c_conn_state == SLAP_C_CLIENT ) {
			continue;
		}
		connection_closing( c, "dropping" );
		connection_close( c );
	}
	connection_done( c );
}

static Connection* connection_get( ber_socket_t s )
{
	Connection *c;

	Debug( LDAP_DEBUG_ARGS,
		"connection_get(%ld)\n",
		(long) s );

	assert( connections != NULL );

	if(s == AC_SOCKET_INVALID) return NULL;

	assert( s < dtblsize );
	c = &connections[s];

	if( c != NULL ) {
		ldap_pvt_thread_mutex_lock( &c->c_mutex );

		if( c->c_conn_state == SLAP_C_INVALID ) {
			/* connection must have been closed due to resched */

			Debug( LDAP_DEBUG_CONNS,
				"connection_get(%d): connection not used\n",
				s );
			assert( c->c_sd == AC_SOCKET_INVALID );

			ldap_pvt_thread_mutex_unlock( &c->c_mutex );
			return NULL;
		}

		Debug( LDAP_DEBUG_TRACE,
			"connection_get(%d): got connid=%lu\n",
			s, c->c_connid );

		c->c_n_get++;

		assert( c->c_conn_state != SLAP_C_INVALID );
		assert( c->c_sd != AC_SOCKET_INVALID );

		c->c_activitytime = slap_get_time();
	}

	return c;
}

static void connection_return( Connection *c )
{
	ldap_pvt_thread_mutex_unlock( &c->c_mutex );
}

Connection * connection_init(
	ber_socket_t s,
	Listener *listener,
	const char* dnsname,
	const char* peername,
	int flags,
	slap_ssf_t ssf,
	struct berval *authid
	LDAP_PF_LOCAL_SENDMSG_ARG(struct berval *peerbv))
{
	unsigned long id;
	Connection *c;
	ber_socket_t sfd = SLAP_FD2SOCK(s);

	assert( connections != NULL );

	assert( listener != NULL );
	assert( dnsname != NULL );
	assert( peername != NULL );

#ifndef HAVE_TLS
	assert( !( flags & CONN_IS_TLS ));
#endif

	if( s == AC_SOCKET_INVALID ) {
		Debug( LDAP_DEBUG_ANY,
			"connection_init: init of socket %ld invalid.\n", (long)s );
		return NULL;
	}

	assert( s >= 0 );
	assert( s < dtblsize );
	c = &connections[s];

	ldap_pvt_thread_mutex_lock( &c->c_mutex );

	if( !c->c_sb ) {
		c->c_send_ldap_result = slap_send_ldap_result;
		c->c_send_search_entry = slap_send_search_entry;
		c->c_send_search_reference = slap_send_search_reference;
		c->c_send_ldap_extended = slap_send_ldap_extended;
		c->c_send_ldap_intermediate = slap_send_ldap_intermediate;

		BER_BVZERO( &c->c_authmech );
		BER_BVZERO( &c->c_dn );
		BER_BVZERO( &c->c_ndn );

		c->c_listener = NULL;
		BER_BVZERO( &c->c_peer_domain );
		BER_BVZERO( &c->c_peer_name );

		LDAP_STAILQ_INIT(&c->c_ops);
		LDAP_STAILQ_INIT(&c->c_pending_ops);

		c->c_txn = CONN_TXN_INACTIVE;
		c->c_txn_backend = NULL;
		LDAP_STAILQ_INIT(&c->c_txn_ops);

		BER_BVZERO( &c->c_sasl_bind_mech );
		c->c_sasl_done = 0;
		c->c_sasl_authctx = NULL;
		c->c_sasl_sockctx = NULL;
		c->c_sasl_extra = NULL;
		c->c_sasl_bindop = NULL;
		c->c_sasl_cbind = NULL;

		c->c_sb = ber_sockbuf_alloc( );

		{
			ber_len_t max = sockbuf_max_incoming;
			ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_SET_MAX_INCOMING, &max );
		}

		c->c_currentber = NULL;

#ifdef LDAP_SLAPI
		if ( slapi_plugins_used ) {
			slapi_int_create_object_extensions( SLAPI_X_EXT_CONNECTION, c );
		}
#endif
	}

	assert( BER_BVISNULL( &c->c_authmech ) );
	assert( BER_BVISNULL( &c->c_dn ) );
	assert( BER_BVISNULL( &c->c_ndn ) );
	assert( c->c_listener == NULL );
	assert( BER_BVISNULL( &c->c_peer_domain ) );
	assert( BER_BVISNULL( &c->c_peer_name ) );
	assert( LDAP_STAILQ_EMPTY(&c->c_ops) );
	assert( LDAP_STAILQ_EMPTY(&c->c_pending_ops) );
	assert( c->c_txn == CONN_TXN_INACTIVE );
	assert( c->c_txn_backend == NULL );
	assert( LDAP_STAILQ_EMPTY(&c->c_txn_ops) );
	assert( BER_BVISNULL( &c->c_sasl_bind_mech ) );
	assert( c->c_sasl_done == 0 );
	assert( c->c_sasl_authctx == NULL );
	assert( c->c_sasl_sockctx == NULL );
	assert( c->c_sasl_extra == NULL );
	assert( c->c_sasl_bindop == NULL );
	assert( c->c_sasl_cbind == NULL );
	assert( c->c_currentber == NULL );
	assert( c->c_writewaiter == 0);
	assert( c->c_writers == 0);

	c->c_listener = listener;
	c->c_sd = s;

	if ( flags & CONN_IS_CLIENT ) {
		c->c_connid = 0;
		c->c_conn_state = SLAP_C_CLIENT;
		c->c_close_reason = "?";			/* should never be needed */
		ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_SET_FD, &sfd );
		ldap_pvt_thread_mutex_unlock( &c->c_mutex );

		return c;
	}

	ber_str2bv( dnsname, 0, 1, &c->c_peer_domain );
	ber_str2bv( peername, 0, 1, &c->c_peer_name );

	c->c_n_ops_received = 0;
	c->c_n_ops_executing = 0;
	c->c_n_ops_pending = 0;
	c->c_n_ops_completed = 0;

	c->c_n_get = 0;
	c->c_n_read = 0;
	c->c_n_write = 0;

	/* set to zero until bind, implies LDAP_VERSION3 */
	c->c_protocol = 0;

	c->c_activitytime = c->c_starttime = slap_get_time();

#ifdef LDAP_CONNECTIONLESS
	c->c_is_udp = 0;
	if( flags & CONN_IS_UDP ) {
		c->c_is_udp = 1;
#ifdef LDAP_DEBUG
		ber_sockbuf_add_io( c->c_sb, &ber_sockbuf_io_debug,
			LBER_SBIOD_LEVEL_PROVIDER, (void*)"udp_" );
#endif
		ber_sockbuf_add_io( c->c_sb, &ber_sockbuf_io_udp,
			LBER_SBIOD_LEVEL_PROVIDER, (void *)&sfd );
		ber_sockbuf_add_io( c->c_sb, &ber_sockbuf_io_readahead,
			LBER_SBIOD_LEVEL_PROVIDER, NULL );
	} else
#endif /* LDAP_CONNECTIONLESS */
#ifdef LDAP_PF_LOCAL
	if ( flags & CONN_IS_IPC ) {
#ifdef LDAP_DEBUG
		ber_sockbuf_add_io( c->c_sb, &ber_sockbuf_io_debug,
			LBER_SBIOD_LEVEL_PROVIDER, (void*)"ipc_" );
#endif
		ber_sockbuf_add_io( c->c_sb, &ber_sockbuf_io_fd,
			LBER_SBIOD_LEVEL_PROVIDER, (void *)&sfd );
#ifdef LDAP_PF_LOCAL_SENDMSG
		if ( !BER_BVISEMPTY( peerbv ))
			ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_UNGET_BUF, peerbv );
#endif
	} else
#endif /* LDAP_PF_LOCAL */
	{
#ifdef LDAP_DEBUG
		ber_sockbuf_add_io( c->c_sb, &ber_sockbuf_io_debug,
			LBER_SBIOD_LEVEL_PROVIDER, (void*)"tcp_" );
#endif
		ber_sockbuf_add_io( c->c_sb, &ber_sockbuf_io_tcp,
			LBER_SBIOD_LEVEL_PROVIDER, (void *)&sfd );
	}

#ifdef LDAP_DEBUG
	ber_sockbuf_add_io( c->c_sb, &ber_sockbuf_io_debug,
		INT_MAX, (void*)"ldap_" );
#endif

	if( ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_SET_NONBLOCK,
		c /* non-NULL */ ) < 0 )
	{
		Debug( LDAP_DEBUG_ANY,
			"connection_init(%d, %s): set nonblocking failed\n",
			s, c->c_peer_name.bv_val );

		c->c_listener = NULL;
		if(c->c_peer_domain.bv_val != NULL) {
			free(c->c_peer_domain.bv_val);
		}
		BER_BVZERO( &c->c_peer_domain );
		if(c->c_peer_name.bv_val != NULL) {
			free(c->c_peer_name.bv_val);
		}
		BER_BVZERO( &c->c_peer_name );

		ber_sockbuf_free( c->c_sb );
		c->c_sb = ber_sockbuf_alloc( );
		{
			ber_len_t max = sockbuf_max_incoming;
			ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_SET_MAX_INCOMING, &max );
		}

		c->c_sd = AC_SOCKET_INVALID;
		ldap_pvt_thread_mutex_unlock( &c->c_mutex );

		return NULL;
	}

	ldap_pvt_thread_mutex_lock( &conn_nextid_mutex );
	id = c->c_connid = conn_nextid++;
	ldap_pvt_thread_mutex_unlock( &conn_nextid_mutex );

	c->c_conn_state = SLAP_C_INACTIVE;
	c->c_close_reason = "?";			/* should never be needed */

	c->c_ssf = c->c_transport_ssf = ssf;
	c->c_tls_ssf = c->c_sasl_ssf = 0;

#ifdef HAVE_TLS
	if ( flags & CONN_IS_TLS ) {
		c->c_is_tls = 1;
		c->c_needs_tls_accept = 1;
	} else {
		c->c_is_tls = 0;
		c->c_needs_tls_accept = 0;
	}
#endif

	slap_sasl_open( c, 0 );
	slap_sasl_external( c, ssf, authid );

	slapd_add_internal( s, 1 );

	backend_connection_init(c);
	ldap_pvt_thread_mutex_unlock( &c->c_mutex );

	if ( !(flags & CONN_IS_UDP ))
		Debug( LDAP_DEBUG_STATS,
			"conn=%ld fd=%ld ACCEPT from %s (%s)\n",
			id, (long) s, peername, listener->sl_name.bv_val );

	return c;
}

void connection2anonymous( Connection *c )
{
	assert( connections != NULL );
	assert( c != NULL );

	{
		ber_len_t max = sockbuf_max_incoming;
		ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_SET_MAX_INCOMING, &max );
	}

	if ( !BER_BVISNULL( &c->c_authmech ) ) {
		ch_free(c->c_authmech.bv_val);
	}
	BER_BVZERO( &c->c_authmech );

	if ( !BER_BVISNULL( &c->c_dn ) ) {
		ch_free(c->c_dn.bv_val);
	}
	BER_BVZERO( &c->c_dn );

	if ( !BER_BVISNULL( &c->c_ndn ) ) {
		ch_free(c->c_ndn.bv_val);
	}
	BER_BVZERO( &c->c_ndn );

	if ( !BER_BVISNULL( &c->c_sasl_authz_dn ) ) {
		ber_memfree_x( c->c_sasl_authz_dn.bv_val, NULL );
	}
	BER_BVZERO( &c->c_sasl_authz_dn );

	c->c_authz_backend = NULL;
}

static void
connection_destroy( Connection *c )
{
	unsigned long	connid;
	const char		*close_reason;
	Sockbuf			*sb;
	ber_socket_t	sd;

	assert( connections != NULL );
	assert( c != NULL );
	assert( c->c_conn_state != SLAP_C_INVALID );
	assert( LDAP_STAILQ_EMPTY(&c->c_ops) );
	assert( LDAP_STAILQ_EMPTY(&c->c_pending_ops) );
	assert( c->c_txn == CONN_TXN_INACTIVE );
	assert( c->c_txn_backend == NULL );
	assert( LDAP_STAILQ_EMPTY(&c->c_txn_ops) );
	assert( c->c_writewaiter == 0);
	assert( c->c_writers == 0);

	/* only for stats (print -1 as "%lu" may give unexpected results ;) */
	connid = c->c_connid;
	close_reason = c->c_close_reason;

	backend_connection_destroy(c);

	c->c_protocol = 0;
	c->c_connid = -1;

	c->c_activitytime = c->c_starttime = 0;

	connection2anonymous( c );
	c->c_listener = NULL;

	if(c->c_peer_domain.bv_val != NULL) {
		free(c->c_peer_domain.bv_val);
	}
	BER_BVZERO( &c->c_peer_domain );
	if(c->c_peer_name.bv_val != NULL) {
		free(c->c_peer_name.bv_val);
	}
	BER_BVZERO( &c->c_peer_name );

	c->c_sasl_bind_in_progress = 0;
	if(c->c_sasl_bind_mech.bv_val != NULL) {
		free(c->c_sasl_bind_mech.bv_val);
	}
	BER_BVZERO( &c->c_sasl_bind_mech );

	slap_sasl_close( c );

	if ( c->c_currentber != NULL ) {
		ber_free( c->c_currentber, 1 );
		c->c_currentber = NULL;
	}


#ifdef LDAP_SLAPI
	/* call destructors, then constructors; avoids unnecessary allocation */
	if ( slapi_plugins_used ) {
		slapi_int_clear_object_extensions( SLAPI_X_EXT_CONNECTION, c );
	}
#endif

	sd = c->c_sd;
	c->c_sd = AC_SOCKET_INVALID;
	c->c_close_reason = "?";			/* should never be needed */

	sb = c->c_sb;
	c->c_sb = ber_sockbuf_alloc( );
	{
		ber_len_t max = sockbuf_max_incoming;
		ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_SET_MAX_INCOMING, &max );
	}
	c->c_conn_state = SLAP_C_INVALID;

	/* c must be fully reset by this point; when we call slapd_remove
	 * it may get immediately reused by a new connection.
	 */
	if ( sd != AC_SOCKET_INVALID ) {
		slapd_remove( sd, sb, 1, 0, 0 );

		if ( close_reason == NULL ) {
			Debug( LDAP_DEBUG_STATS, "conn=%lu fd=%ld closed\n",
				connid, (long) sd );
		} else {
			Debug( LDAP_DEBUG_STATS, "conn=%lu fd=%ld closed (%s)\n",
				connid, (long) sd, close_reason );
		}
	}
}

int connection_is_active( ber_socket_t s )
{
	Connection *c;

	assert( s < dtblsize );
	c = &connections[s];
	return c->c_conn_state == SLAP_C_CLOSING ||
		c->c_conn_state == SLAP_C_BINDING ||
		c->c_conn_state == SLAP_C_ACTIVE ;
}

int connection_valid( Connection *c )
{
	/* c_mutex must be locked by caller */

	assert( c != NULL );

	return c->c_conn_state >= SLAP_C_ACTIVE &&
		c->c_conn_state <= SLAP_C_CLIENT;
}

static void connection_abandon( Connection *c )
{
	/* c_mutex must be locked by caller */

	Operation *o, *next, op = {0};
	Opheader ohdr = {0};

	op.o_hdr = &ohdr;
	op.o_conn = c;
	op.o_connid = c->c_connid;
	op.o_tag = LDAP_REQ_ABANDON;

	for ( o = LDAP_STAILQ_FIRST( &c->c_ops ); o; o=next ) {
		SlapReply rs = {REP_RESULT};

		next = LDAP_STAILQ_NEXT( o, o_next );
		/* don't abandon an op twice */
		if ( o->o_abandon )
			continue;
		op.orn_msgid = o->o_msgid;
		o->o_abandon = 1;
		op.o_bd = frontendDB;
		frontendDB->be_abandon( &op, &rs );
	}

	/* remove operations in pending transaction */
	while ( (o = LDAP_STAILQ_FIRST( &c->c_txn_ops )) != NULL) {
		LDAP_STAILQ_REMOVE_HEAD( &c->c_txn_ops, o_next );
		LDAP_STAILQ_NEXT(o, o_next) = NULL;
		slap_op_free( o, NULL );
	}

	/* clear transaction */
	c->c_txn_backend = NULL;
	c->c_txn = CONN_TXN_INACTIVE;

	/* remove pending operations */
	while ( (o = LDAP_STAILQ_FIRST( &c->c_pending_ops )) != NULL) {
		LDAP_STAILQ_REMOVE_HEAD( &c->c_pending_ops, o_next );
		LDAP_STAILQ_NEXT(o, o_next) = NULL;
		slap_op_free( o, NULL );
	}
}

static void
connection_wake_writers( Connection *c )
{
	/* wake write blocked operations */
	ldap_pvt_thread_mutex_lock( &c->c_write1_mutex );
	if ( c->c_writers > 0 ) {
		c->c_writers = -c->c_writers;
		ldap_pvt_thread_cond_broadcast( &c->c_write1_cv );
		ldap_pvt_thread_mutex_unlock( &c->c_write1_mutex );
		if ( c->c_writewaiter ) {
			slapd_shutsock( c->c_sd );
		}
		ldap_pvt_thread_mutex_lock( &c->c_write1_mutex );
		while ( c->c_writers ) {
			ldap_pvt_thread_cond_wait( &c->c_write1_cv, &c->c_write1_mutex );
		}
		ldap_pvt_thread_mutex_unlock( &c->c_write1_mutex );
	} else {
		ldap_pvt_thread_mutex_unlock( &c->c_write1_mutex );
		slapd_clr_write( c->c_sd, 1 );
	}
}

void connection_closing( Connection *c, const char *why )
{
	assert( connections != NULL );
	assert( c != NULL );

	if( c->c_conn_state == SLAP_C_INVALID )
		return;

	/* c_mutex must be locked by caller */

	if( c->c_conn_state != SLAP_C_CLOSING ) {
		Debug( LDAP_DEBUG_CONNS,
			"connection_closing: readying conn=%lu sd=%d for close\n",
			c->c_connid, c->c_sd );
		/* update state to closing */
		c->c_conn_state = SLAP_C_CLOSING;
		c->c_close_reason = why;

		/* don't listen on this port anymore */
		slapd_clr_read( c->c_sd, 0 );

		/* abandon active operations */
		connection_abandon( c );

		/* wake write blocked operations */
		connection_wake_writers( c );

	} else if( why == NULL && c->c_close_reason == conn_lost_str ) {
		/* Client closed connection after doing Unbind. */
		c->c_close_reason = NULL;
	}
}

static void
connection_close( Connection *c )
{
	assert( connections != NULL );
	assert( c != NULL );

	if ( c->c_conn_state != SLAP_C_CLOSING )
		return;

	/* NOTE: c_mutex should be locked by caller */

	if ( !LDAP_STAILQ_EMPTY(&c->c_ops) ||
		!LDAP_STAILQ_EMPTY(&c->c_pending_ops) )
	{
		Debug( LDAP_DEBUG_CONNS,
			"connection_close: deferring conn=%lu sd=%d\n",
			c->c_connid, c->c_sd );
		return;
	}

	Debug( LDAP_DEBUG_TRACE, "connection_close: conn=%lu sd=%d\n",
		c->c_connid, c->c_sd );

	connection_destroy( c );
}

unsigned long connections_nextid(void)
{
	unsigned long id;
	assert( connections != NULL );

	ldap_pvt_thread_mutex_lock( &conn_nextid_mutex );

	id = conn_nextid;

	ldap_pvt_thread_mutex_unlock( &conn_nextid_mutex );

	return id;
}

/*
 * Loop through the connections:
 *
 *	for (c = connection_first(&i); c; c = connection_next(c, &i)) ...;
 *	connection_done(c);
 *
 * 'i' is the cursor, initialized by connection_first().
 * 'c_mutex' is locked in the returned connection.  The functions must
 * be passed the previous return value so they can unlock it again.
 */

Connection* connection_first( ber_socket_t *index )
{
	assert( connections != NULL );
	assert( index != NULL );

	for( *index = 0; *index < dtblsize; (*index)++) {
		if( connections[*index].c_sb ) {
			break;
		}
	}

	return connection_next(NULL, index);
}

/* Next connection in loop, see connection_first() */
Connection* connection_next( Connection *c, ber_socket_t *index )
{
	assert( connections != NULL );
	assert( index != NULL );
	assert( *index <= dtblsize );

	if( c != NULL ) ldap_pvt_thread_mutex_unlock( &c->c_mutex );

	c = NULL;

	for(; *index < dtblsize; (*index)++) {
		if( connections[*index].c_sb ) {
			c = &connections[(*index)++];
			ldap_pvt_thread_mutex_lock( &c->c_mutex );
			if ( c->c_conn_state == SLAP_C_INVALID ) {
				ldap_pvt_thread_mutex_unlock( &c->c_mutex );
				c = NULL;
				continue;
			}
			break;
		}
	}

	return c;
}

/* End connection loop, see connection_first() */
void connection_done( Connection *c )
{
	assert( connections != NULL );

	if( c != NULL ) ldap_pvt_thread_mutex_unlock( &c->c_mutex );
}

/*
 * connection_activity - handle the request operation op on connection
 * conn.  This routine figures out what kind of operation it is and
 * calls the appropriate stub to handle it.
 */

/* FIXME: returns 0 in case of failure */
#define INCR_OP_INITIATED(index) \
	do { \
		ldap_pvt_thread_mutex_lock( &op->o_counters->sc_mutex ); \
		ldap_pvt_mp_add_ulong(op->o_counters->sc_ops_initiated_[(index)], 1); \
		ldap_pvt_thread_mutex_unlock( &op->o_counters->sc_mutex ); \
	} while (0)
#define INCR_OP_COMPLETED(index) \
	do { \
		ldap_pvt_thread_mutex_lock( &op->o_counters->sc_mutex ); \
		ldap_pvt_mp_add_ulong(op->o_counters->sc_ops_completed, 1); \
		ldap_pvt_mp_add_ulong(op->o_counters->sc_ops_completed_[(index)], 1); \
		ldap_pvt_thread_mutex_unlock( &op->o_counters->sc_mutex ); \
	} while (0)

/*
 * NOTE: keep in sync with enum in slapd.h
 */
static BI_op_func *opfun[] = {
	do_bind,
	do_unbind,
	do_search,
	do_compare,
	do_modify,
	do_modrdn,
	do_add,
	do_delete,
	do_abandon,
	do_extended,
	NULL
};

/* Counters are per-thread, not per-connection.
 */
static void
conn_counter_destroy( void *key, void *data )
{
	slap_counters_t **prev, *sc;

	ldap_pvt_thread_mutex_lock( &slap_counters.sc_mutex );
	for ( prev = &slap_counters.sc_next, sc = slap_counters.sc_next; sc;
		prev = &sc->sc_next, sc = sc->sc_next ) {
		if ( sc == data ) {
			int i;

			*prev = sc->sc_next;
			/* Copy data to main counter */
			ldap_pvt_mp_add( slap_counters.sc_bytes, sc->sc_bytes );
			ldap_pvt_mp_add( slap_counters.sc_pdu, sc->sc_pdu );
			ldap_pvt_mp_add( slap_counters.sc_entries, sc->sc_entries );
			ldap_pvt_mp_add( slap_counters.sc_refs, sc->sc_refs );
			ldap_pvt_mp_add( slap_counters.sc_ops_initiated, sc->sc_ops_initiated );
			ldap_pvt_mp_add( slap_counters.sc_ops_completed, sc->sc_ops_completed );
			for ( i = 0; i < SLAP_OP_LAST; i++ ) {
				ldap_pvt_mp_add( slap_counters.sc_ops_initiated_[ i ], sc->sc_ops_initiated_[ i ] );
				ldap_pvt_mp_add( slap_counters.sc_ops_initiated_[ i ], sc->sc_ops_completed_[ i ] );
			}
			slap_counters_destroy( sc );
			ber_memfree_x( data, NULL );
			break;
		}
	}
	ldap_pvt_thread_mutex_unlock( &slap_counters.sc_mutex );
}

static void
conn_counter_init( Operation *op, void *ctx )
{
	slap_counters_t *sc;
	void *vsc = NULL;

	if ( ldap_pvt_thread_pool_getkey(
			ctx, (void *)conn_counter_init, &vsc, NULL ) || !vsc ) {
		vsc = ch_malloc( sizeof( slap_counters_t ));
		sc = vsc;
		slap_counters_init( sc );
		ldap_pvt_thread_pool_setkey( ctx, (void*)conn_counter_init, vsc,
			conn_counter_destroy, NULL, NULL );

		ldap_pvt_thread_mutex_lock( &slap_counters.sc_mutex );
		sc->sc_next = slap_counters.sc_next;
		slap_counters.sc_next = sc;
		ldap_pvt_thread_mutex_unlock( &slap_counters.sc_mutex );
	}
	op->o_counters = vsc;
}

void
connection_op_finish( Operation *op )
{
	Connection *conn = op->o_conn;
	void *memctx_null = NULL;
	slap_op_t opidx = slap_req2op( op->o_tag );
	assert( opidx != SLAP_OP_LAST );

	INCR_OP_COMPLETED( opidx );

	ldap_pvt_thread_mutex_lock( &conn->c_mutex );

	if ( op->o_tag == LDAP_REQ_BIND && conn->c_conn_state == SLAP_C_BINDING )
		conn->c_conn_state = SLAP_C_ACTIVE;

	ber_set_option( op->o_ber, LBER_OPT_BER_MEMCTX, &memctx_null );

	LDAP_STAILQ_REMOVE( &conn->c_ops, op, Operation, o_next);
	LDAP_STAILQ_NEXT(op, o_next) = NULL;
	conn->c_n_ops_executing--;
	conn->c_n_ops_completed++;
	connection_resched( conn );
	ldap_pvt_thread_mutex_unlock( &conn->c_mutex );
}

static void *
connection_operation( void *ctx, void *arg_v )
{
	int rc = LDAP_OTHER, cancel;
	Operation *op = arg_v;
	SlapReply rs = {REP_RESULT};
	ber_tag_t tag = op->o_tag;
	slap_op_t opidx = SLAP_OP_LAST;
	Connection *conn = op->o_conn;
	void *memctx = NULL;
	void *memctx_null = NULL;
	ber_len_t memsiz;

	gettimeofday( &op->o_qtime, NULL );
	op->o_qtime.tv_usec -= op->o_tusec;
	if ( op->o_qtime.tv_usec < 0 ) {
		op->o_qtime.tv_usec += 1000000;
		op->o_qtime.tv_sec--;
	}
	op->o_qtime.tv_sec -= op->o_time;
	conn_counter_init( op, ctx );
	ldap_pvt_thread_mutex_lock( &op->o_counters->sc_mutex );
	/* FIXME: returns 0 in case of failure */
	ldap_pvt_mp_add_ulong(op->o_counters->sc_ops_initiated, 1);
	ldap_pvt_thread_mutex_unlock( &op->o_counters->sc_mutex );

	op->o_threadctx = ctx;
	op->o_tid = ldap_pvt_thread_pool_tid( ctx );

	switch ( tag ) {
	case LDAP_REQ_BIND:
	case LDAP_REQ_UNBIND:
	case LDAP_REQ_ADD:
	case LDAP_REQ_DELETE:
	case LDAP_REQ_MODDN:
	case LDAP_REQ_MODIFY:
	case LDAP_REQ_COMPARE:
	case LDAP_REQ_SEARCH:
	case LDAP_REQ_ABANDON:
	case LDAP_REQ_EXTENDED:
		break;
	default:
		Debug( LDAP_DEBUG_ANY, "connection_operation: "
			"conn %lu unknown LDAP request 0x%lx\n",
			conn->c_connid, tag );
		op->o_tag = LBER_ERROR;
		rs.sr_err = LDAP_PROTOCOL_ERROR;
		rs.sr_text = "unknown LDAP request";
		send_ldap_disconnect( op, &rs );
		rc = SLAPD_DISCONNECT;
		goto operations_error;
	}

	if( conn->c_sasl_bind_in_progress && tag != LDAP_REQ_BIND ) {
		Debug( LDAP_DEBUG_ANY, "connection_operation: "
			"error: SASL bind in progress (tag=%ld).\n",
			(long) tag );
		send_ldap_error( op, &rs, LDAP_OPERATIONS_ERROR,
			"SASL bind in progress" );
		rc = LDAP_OPERATIONS_ERROR;
		goto operations_error;
	}

	if (( conn->c_txn == CONN_TXN_SPECIFY ) && (
		( tag == LDAP_REQ_ADD ) ||
		( tag == LDAP_REQ_DELETE ) ||
		( tag == LDAP_REQ_MODIFY ) ||
		( tag == LDAP_REQ_MODRDN )))
	{
		/* Disable SLAB allocator for all update operations
			issued inside of a transaction */
		op->o_tmpmemctx = NULL;
		op->o_tmpmfuncs = &ch_mfuncs;
	} else {
	/* We can use Thread-Local storage for most mallocs. We can
	 * also use TL for ber parsing, but not on Add or Modify.
	 */
#if 0
	memsiz = ber_len( op->o_ber ) * 64;
	if ( SLAP_SLAB_SIZE > memsiz ) memsiz = SLAP_SLAB_SIZE;
#endif
	memsiz = SLAP_SLAB_SIZE;

	memctx = slap_sl_mem_create( memsiz, SLAP_SLAB_STACK, ctx, 1 );
	op->o_tmpmemctx = memctx;
	op->o_tmpmfuncs = &slap_sl_mfuncs;
	if ( tag != LDAP_REQ_ADD && tag != LDAP_REQ_MODIFY ) {
		/* Note - the ber and its buffer are already allocated from
		 * regular memory; this only affects subsequent mallocs that
		 * ber_scanf may invoke.
		 */
		ber_set_option( op->o_ber, LBER_OPT_BER_MEMCTX, &memctx );
	}
	}

	opidx = slap_req2op( tag );
	assert( opidx != SLAP_OP_LAST );
	INCR_OP_INITIATED( opidx );
	rc = (*(opfun[opidx]))( op, &rs );

operations_error:
	if ( rc == SLAPD_DISCONNECT ) {
		tag = LBER_ERROR;

    } else if ( rc == SLAPD_ASYNCOP ) {
		/* someone has claimed ownership of the op
		 * to complete it later. Don't do anything
		 * else with it now. Detach memctx too.
		 */
		slap_sl_mem_setctx( ctx, NULL );
		ldap_pvt_thread_mutex_lock( &conn->c_mutex );
		connection_resched( conn );
		ldap_pvt_thread_mutex_unlock( &conn->c_mutex );
		return NULL;

	} else if ( opidx != SLAP_OP_LAST ) {
		/* increment completed operations count
		 * only if operation was initiated
		 * and rc != SLAPD_DISCONNECT */
		INCR_OP_COMPLETED( opidx );
	}

	ldap_pvt_thread_mutex_lock( &conn->c_mutex );

	if ( opidx == SLAP_OP_BIND && conn->c_conn_state == SLAP_C_BINDING )
		conn->c_conn_state = SLAP_C_ACTIVE;

	cancel = op->o_cancel;
	if ( cancel != SLAP_CANCEL_NONE && cancel != SLAP_CANCEL_DONE ) {
		if ( cancel == SLAP_CANCEL_REQ ) {
			op->o_cancel = rc == SLAPD_ABANDON
				? SLAP_CANCEL_ACK : LDAP_TOO_LATE;
		}

		do {
			/* Fake a cond_wait with thread_yield, then
			 * verify the result properly mutex-protected.
			 */
			ldap_pvt_thread_mutex_unlock( &conn->c_mutex );
			do {
				ldap_pvt_thread_yield();
			} while ( (cancel = op->o_cancel) != SLAP_CANCEL_NONE
					&& cancel != SLAP_CANCEL_DONE );
			ldap_pvt_thread_mutex_lock( &conn->c_mutex );
		} while ( (cancel = op->o_cancel) != SLAP_CANCEL_NONE
				&& cancel != SLAP_CANCEL_DONE );
	}

	ber_set_option( op->o_ber, LBER_OPT_BER_MEMCTX, &memctx_null );

	if ( rc != LDAP_TXN_SPECIFY_OKAY ) {
		LDAP_STAILQ_REMOVE( &conn->c_ops, op, Operation, o_next);
		LDAP_STAILQ_NEXT(op, o_next) = NULL;
	}
	conn->c_n_ops_executing--;
	conn->c_n_ops_completed++;

	switch( tag ) {
	case LBER_ERROR:
	case LDAP_REQ_UNBIND:
		/* c_mutex is locked */
		connection_closing( conn,
			tag == LDAP_REQ_UNBIND ? NULL : "operations error" );
		break;
	}

	connection_resched( conn );
	ldap_pvt_thread_mutex_unlock( &conn->c_mutex );
	if ( rc != LDAP_TXN_SPECIFY_OKAY ) {
		slap_op_free( op, ctx );
	}
	return NULL;
}

static const Listener dummy_list = { BER_BVC(""), BER_BVC("") };

Connection *connection_client_setup(
	ber_socket_t s,
	ldap_pvt_thread_start_t *func,
	void *arg )
{
	Connection *c;
	ber_socket_t sfd = SLAP_SOCKNEW( s );

	c = connection_init( sfd, (Listener *)&dummy_list, "", "",
		CONN_IS_CLIENT, 0, NULL
		LDAP_PF_LOCAL_SENDMSG_ARG(NULL));
	if ( c ) {
		c->c_clientfunc = func;
		c->c_clientarg = arg;

		slapd_add_internal( sfd, 0 );
	}
	return c;
}

void connection_client_enable(
	Connection *c )
{
	slapd_set_read( c->c_sd, 1 );
}

void connection_client_stop(
	Connection *c )
{
	Sockbuf *sb;
	ber_socket_t s = c->c_sd;

	/* get (locked) connection */
	c = connection_get( s );

	assert( c->c_conn_state == SLAP_C_CLIENT );

	c->c_listener = NULL;
	c->c_sd = AC_SOCKET_INVALID;
	c->c_close_reason = "?";			/* should never be needed */
	sb = c->c_sb;
	c->c_sb = ber_sockbuf_alloc( );
	{
		ber_len_t max = sockbuf_max_incoming;
		ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_SET_MAX_INCOMING, &max );
	}
	c->c_conn_state = SLAP_C_INVALID;
	slapd_remove( s, sb, 0, 1, 0 );

	connection_return( c );
}

static int connection_read( ber_socket_t s, conn_readinfo *cri );

static void* connection_read_thread( void* ctx, void* argv )
{
	int rc ;
	conn_readinfo cri = { NULL, NULL, NULL, NULL, 0 };
	ber_socket_t s = (long)argv;

	/*
	 * read incoming LDAP requests. If there is more than one,
	 * the first one is returned with new_op
	 */
	cri.ctx = ctx;
	if( ( rc = connection_read( s, &cri ) ) < 0 ) {
		Debug( LDAP_DEBUG_CONNS, "connection_read(%d) error\n", s );
		return (void*)(long)rc;
	}

	/* execute a single queued request in the same thread */
	if( cri.op && !cri.nullop ) {
		rc = (long)connection_operation( ctx, cri.op );
	} else if ( cri.func ) {
		rc = (long)cri.func( ctx, cri.arg );
	}

	return (void*)(long)rc;
}

int connection_read_activate( ber_socket_t s )
{
	int rc;

	/*
	 * suspend reading on this file descriptor until a connection processing
	 * thread reads data on it. Otherwise the listener thread will repeatedly
	 * submit the same event on it to the pool.
	 */
	rc = slapd_clr_read( s, 0 );
	if ( rc )
		return rc;

	rc = ldap_pvt_thread_pool_submit( &connection_pool,
		connection_read_thread, (void *)(long)s );

	if( rc != 0 ) {
		Debug( LDAP_DEBUG_ANY,
			"connection_read_activate(%d): submit failed (%d)\n",
			s, rc );
	}

	return rc;
}

static int
connection_read( ber_socket_t s, conn_readinfo *cri )
{
	int rc = 0;
	Connection *c;

	assert( connections != NULL );

	/* get (locked) connection */
	c = connection_get( s );

	if( c == NULL ) {
		Debug( LDAP_DEBUG_ANY,
			"connection_read(%ld): no connection!\n",
			(long) s );

		return -1;
	}

	c->c_n_read++;

	if( c->c_conn_state == SLAP_C_CLOSING ) {
		Debug( LDAP_DEBUG_CONNS,
			"connection_read(%d): closing, ignoring input for id=%lu\n",
			s, c->c_connid );
		connection_return( c );
		return 0;
	}

	if ( c->c_conn_state == SLAP_C_CLIENT ) {
		cri->func = c->c_clientfunc;
		cri->arg = c->c_clientarg;
		/* read should already be cleared */
		connection_return( c );
		return 0;
	}

	Debug( LDAP_DEBUG_TRACE,
		"connection_read(%d): checking for input on id=%lu\n",
		s, c->c_connid );

#ifdef HAVE_TLS
	if ( c->c_is_tls && c->c_needs_tls_accept ) {
		rc = ldap_pvt_tls_accept( c->c_sb, slap_tls_ctx );
		if ( rc < 0 ) {
			Debug( LDAP_DEBUG_TRACE,
				"connection_read(%d): TLS accept failure "
				"error=%d id=%lu, closing\n",
				s, rc, c->c_connid );

			c->c_needs_tls_accept = 0;
			/* c_mutex is locked */
			connection_closing( c, "TLS negotiation failure" );
			connection_close( c );
			connection_return( c );
			return 0;

		} else if ( rc == 0 ) {
			void *ssl;
			struct berval authid = BER_BVNULL;
			char msgbuf[32];

			c->c_needs_tls_accept = 0;

			/* we need to let SASL know */
			ssl = ldap_pvt_tls_sb_ctx( c->c_sb );

			c->c_tls_ssf = (slap_ssf_t) ldap_pvt_tls_get_strength( ssl );
			if( c->c_tls_ssf > c->c_ssf ) {
				c->c_ssf = c->c_tls_ssf;
			}

			rc = dnX509peerNormalize( ssl, &authid );
			if ( rc != LDAP_SUCCESS ) {
				Debug( LDAP_DEBUG_TRACE, "connection_read(%d): "
					"unable to get TLS client DN, error=%d id=%lu\n",
					s, rc, c->c_connid );
			}
			sprintf(msgbuf, "tls_ssf=%u ssf=%u", c->c_tls_ssf, c->c_ssf);
			Debug( LDAP_DEBUG_STATS,
				"conn=%lu fd=%d TLS established %s tls_proto=%s tls_cipher=%s\n",
			    c->c_connid, (int) s,
				msgbuf, ldap_pvt_tls_get_version( ssl ), ldap_pvt_tls_get_cipher( ssl ));
			slap_sasl_external( c, c->c_tls_ssf, &authid );
			if ( authid.bv_val ) free( authid.bv_val );

			slap_sasl_cbinding( c, ssl );

		} else if ( rc == 1 && ber_sockbuf_ctrl( c->c_sb,
			LBER_SB_OPT_NEEDS_WRITE, NULL )) {	/* need to retry */
			slapd_set_write( s, 1 );
			connection_return( c );
			return 0;
		}

		/* if success and data is ready, fall thru to data input loop */
		if( !ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_DATA_READY, NULL ) )
		{
			slapd_set_read( s, 1 );
			connection_return( c );
			return 0;
		}
	}
#endif

#ifdef HAVE_CYRUS_SASL
	if ( c->c_sasl_layers ) {
		/* If previous layer is not removed yet, give up for now */
		if ( !c->c_sasl_sockctx ) {
			slapd_set_read( s, 1 );
			connection_return( c );
			return 0;
		}

		c->c_sasl_layers = 0;

		rc = ldap_pvt_sasl_install( c->c_sb, c->c_sasl_sockctx );
		if( rc != LDAP_SUCCESS ) {
			Debug( LDAP_DEBUG_TRACE,
				"connection_read(%d): SASL install error "
				"error=%d id=%lu, closing\n",
				s, rc, c->c_connid );

			/* c_mutex is locked */
			connection_closing( c, "SASL layer install failure" );
			connection_close( c );
			connection_return( c );
			return 0;
		}
	}
#endif

#define CONNECTION_INPUT_LOOP 1
/* #define	DATA_READY_LOOP 1 */

	do {
		/* How do we do this without getting into a busy loop ? */
		rc = connection_input( c, cri );
	}
#ifdef DATA_READY_LOOP
	while( !rc && ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_DATA_READY, NULL ));
#elif defined CONNECTION_INPUT_LOOP
	while(!rc);
#else
	while(0);
#endif

	if( rc < 0 ) {
		Debug( LDAP_DEBUG_CONNS,
			"connection_read(%d): input error=%d id=%lu, closing.\n",
			s, rc, c->c_connid );

		/* c_mutex is locked */
		connection_closing( c, conn_lost_str );
		connection_close( c );
		connection_return( c );
		return 0;
	}

	if ( ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_NEEDS_WRITE, NULL ) ) {
		slapd_set_write( s, 0 );
	}

	slapd_set_read( s, 1 );
	connection_return( c );

	return 0;
}

static int
connection_input( Connection *conn , conn_readinfo *cri )
{
	Operation *op;
	ber_tag_t	tag;
	ber_len_t	len;
	ber_int_t	msgid;
	BerElement	*ber;
	int 		rc;
#ifdef LDAP_CONNECTIONLESS
	Sockaddr	peeraddr;
	char 		*cdn = NULL;
#endif
	char *defer = NULL;
	void *ctx;

	if ( conn->c_currentber == NULL &&
		( conn->c_currentber = ber_alloc()) == NULL )
	{
		Debug( LDAP_DEBUG_ANY, "ber_alloc failed\n" );
		return -1;
	}

	sock_errset(0);

#ifdef LDAP_CONNECTIONLESS
	if ( conn->c_is_udp ) {
#if defined(LDAP_PF_INET6)
		char peername[sizeof("IP=[ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff]:65535")];
		char addr[INET6_ADDRSTRLEN];
#else
		char peername[sizeof("IP=255.255.255.255:65336")];
		char addr[INET_ADDRSTRLEN];
#endif
		const char *peeraddr_string = NULL;

		len = ber_int_sb_read(conn->c_sb, &peeraddr, sizeof(Sockaddr));
		if (len != sizeof(Sockaddr)) return 1;

#if defined(LDAP_PF_INET6)
		if (peeraddr.sa_addr.sa_family == AF_INET6) {
			if ( IN6_IS_ADDR_V4MAPPED(&peeraddr.sa_in6_addr.sin6_addr) ) {
#if defined( HAVE_GETADDRINFO ) && defined( HAVE_INET_NTOP )
				peeraddr_string = inet_ntop( AF_INET,
				   ((struct in_addr *)&peeraddr.sa_in6_addr.sin6_addr.s6_addr[12]),
				   addr, sizeof(addr) );
#else /* ! HAVE_GETADDRINFO || ! HAVE_INET_NTOP */
				peeraddr_string = inet_ntoa( *((struct in_addr *)
					&peeraddr.sa_in6_addr.sin6_addr.s6_addr[12]) );
#endif /* ! HAVE_GETADDRINFO || ! HAVE_INET_NTOP */
				if ( !peeraddr_string ) peeraddr_string = SLAP_STRING_UNKNOWN;
				sprintf( peername, "IP=%s:%d", peeraddr_string,
					(unsigned) ntohs( peeraddr.sa_in6_addr.sin6_port ) );
			} else {
				peeraddr_string = inet_ntop( AF_INET6,
				      &peeraddr.sa_in6_addr.sin6_addr,
				      addr, sizeof addr );
				if ( !peeraddr_string ) peeraddr_string = SLAP_STRING_UNKNOWN;
				sprintf( peername, "IP=[%s]:%d", peeraddr_string,
					 (unsigned) ntohs( peeraddr.sa_in6_addr.sin6_port ) );
			}
		} else
#endif
#if defined( HAVE_GETADDRINFO ) && defined( HAVE_INET_NTOP )
		{
			peeraddr_string = inet_ntop( AF_INET, &peeraddr.sa_in_addr.sin_addr,
			   addr, sizeof(addr) );
#else /* ! HAVE_GETADDRINFO || ! HAVE_INET_NTOP */
			peeraddr_string = inet_ntoa( peeraddr.sa_in_addr.sin_addr );
#endif /* ! HAVE_GETADDRINFO || ! HAVE_INET_NTOP */
			sprintf( peername, "IP=%s:%d",
				 peeraddr_string,
				(unsigned) ntohs( peeraddr.sa_in_addr.sin_port ) );
		}
		Debug( LDAP_DEBUG_STATS,
			"conn=%lu UDP request from %s (%s) accepted.\n",
			conn->c_connid, peername, conn->c_sock_name.bv_val );
	}
#endif

	tag = ber_get_next( conn->c_sb, &len, conn->c_currentber );
	if ( tag != LDAP_TAG_MESSAGE ) {
		int err = sock_errno();

		if ( err != EWOULDBLOCK && err != EAGAIN ) {
			char ebuf[128];
			/* log, close and send error */
			Debug( LDAP_DEBUG_TRACE,
				"ber_get_next on fd %d failed errno=%d (%s)\n",
			conn->c_sd, err, sock_errstr(err, ebuf, sizeof(ebuf)) );
			ber_free( conn->c_currentber, 1 );
			conn->c_currentber = NULL;

			return -2;
		}
		return 1;
	}

	ber = conn->c_currentber;
	conn->c_currentber = NULL;

	if ( (tag = ber_get_int( ber, &msgid )) != LDAP_TAG_MSGID ) {
		/* log, close and send error */
		Debug( LDAP_DEBUG_ANY, "ber_get_int returns 0x%lx\n", tag );
		ber_free( ber, 1 );
		return -1;
	}

	if ( (tag = ber_peek_tag( ber, &len )) == LBER_ERROR ) {
		/* log, close and send error */
		Debug( LDAP_DEBUG_ANY, "ber_peek_tag returns 0x%lx\n", tag );
		ber_free( ber, 1 );

		return -1;
	}

#ifdef LDAP_CONNECTIONLESS
	if( conn->c_is_udp ) {
		if( tag == LBER_OCTETSTRING ) {
			if ( (tag = ber_get_stringa( ber, &cdn )) != LBER_ERROR )
				tag = ber_peek_tag( ber, &len );
		}
		if( tag != LDAP_REQ_ABANDON && tag != LDAP_REQ_SEARCH ) {
			Debug( LDAP_DEBUG_ANY, "invalid req for UDP 0x%lx\n", tag );
			ber_free( ber, 1 );
			return 0;
		}
	}
#endif

	if(tag == LDAP_REQ_BIND) {
		/* immediately abandon all existing operations upon BIND */
		connection_abandon( conn );
	}

	ctx = cri->ctx;
	op = slap_op_alloc( ber, msgid, tag, conn->c_n_ops_received++, ctx );

	Debug( LDAP_DEBUG_TRACE, "op tag 0x%lx, time %ld\n", tag,
		(long) op->o_time );

	op->o_conn = conn;
	/* clear state if the connection is being reused from inactive */
	if ( conn->c_conn_state == SLAP_C_INACTIVE ) {
		memset( &conn->c_pagedresults_state, 0,
			sizeof( conn->c_pagedresults_state ) );
	}

	op->o_res_ber = NULL;

#ifdef LDAP_CONNECTIONLESS
	if (conn->c_is_udp) {
		if ( cdn ) {
			ber_str2bv( cdn, 0, 1, &op->o_dn );
			op->o_protocol = LDAP_VERSION2;
		}
		op->o_res_ber = ber_alloc_t( LBER_USE_DER );
		if (op->o_res_ber == NULL) return 1;

		rc = ber_write( op->o_res_ber, (char *)&peeraddr,
			sizeof(struct sockaddr), 0 );

		if (rc != sizeof(struct sockaddr)) {
			Debug( LDAP_DEBUG_ANY, "ber_write failed\n" );
			return 1;
		}

		if (op->o_protocol == LDAP_VERSION2) {
			rc = ber_printf(op->o_res_ber, "{is{" /*}}*/, op->o_msgid, "");
			if (rc == -1) {
				Debug( LDAP_DEBUG_ANY, "ber_write failed\n" );
				return rc;
			}
		}
	}
#endif /* LDAP_CONNECTIONLESS */

	rc = 0;

	/* Don't process requests when the conn is in the middle of a
	 * Bind, or if it's closing. Also, don't let any single conn
	 * use up all the available threads, and don't execute if we're
	 * currently blocked on output. And don't execute if there are
	 * already pending ops, let them go first.  Abandon operations
	 * get exceptions to some, but not all, cases.
	 */
	switch( tag ){
	default:
		/* Abandon and Unbind are exempt from these checks */
		if (conn->c_conn_state == SLAP_C_CLOSING) {
			defer = "closing";
			break;
		} else if (conn->c_writewaiter) {
			defer = "awaiting write";
			break;
		} else if (conn->c_n_ops_pending) {
			defer = "pending operations";
			break;
		}
		/* FALLTHRU */
	case LDAP_REQ_ABANDON:
		/* Unbind is exempt from these checks */
		if (conn->c_n_ops_executing >= connection_pool_max/2) {
			defer = "too many executing";
			break;
		} else if (conn->c_conn_state == SLAP_C_BINDING) {
			defer = "binding";
			break;
		}
		/* FALLTHRU */
	case LDAP_REQ_UNBIND:
		break;
	}

	if( defer ) {
		int max = conn->c_dn.bv_len
			? slap_conn_max_pending_auth
			: slap_conn_max_pending;

		Debug( LDAP_DEBUG_ANY,
			"connection_input: conn=%lu deferring operation: %s\n",
			conn->c_connid, defer );
		conn->c_n_ops_pending++;
		LDAP_STAILQ_INSERT_TAIL( &conn->c_pending_ops, op, o_next );
		rc = ( conn->c_n_ops_pending > max ) ? -1 : 0;

	} else {
		conn->c_n_ops_executing++;

		/*
		 * The first op will be processed in the same thread context,
		 * as long as there is only one op total.
		 * Subsequent ops will be submitted to the pool by
		 * calling connection_op_activate()
		 */
		if ( cri->op == NULL ) {
			/* the first incoming request */
			connection_op_queue( op );
			cri->op = op;
		} else {
			if ( !cri->nullop ) {
				cri->nullop = 1;
				rc = ldap_pvt_thread_pool_submit( &connection_pool,
					connection_operation, (void *) cri->op );
			}
			connection_op_activate( op );
		}
	}

	return rc;
}

static int
connection_resched( Connection *conn )
{
	Operation *op;

	if( conn->c_writewaiter )
		return 0;

	if( conn->c_conn_state == SLAP_C_CLOSING ) {
		Debug( LDAP_DEBUG_CONNS, "connection_resched: "
			"attempting closing conn=%lu sd=%d\n",
			conn->c_connid, conn->c_sd );
		connection_close( conn );
		return 0;
	}

	if( conn->c_conn_state != SLAP_C_ACTIVE ) {
		/* other states need different handling */
		return 0;
	}

	while ((op = LDAP_STAILQ_FIRST( &conn->c_pending_ops )) != NULL) {
		if ( conn->c_n_ops_executing > connection_pool_max/2 ) break;

		LDAP_STAILQ_REMOVE_HEAD( &conn->c_pending_ops, o_next );
		LDAP_STAILQ_NEXT(op, o_next) = NULL;

		/* pending operations should not be marked for abandonment */
		assert(!op->o_abandon);

		conn->c_n_ops_pending--;
		conn->c_n_ops_executing++;

		connection_op_activate( op );

		if ( conn->c_conn_state == SLAP_C_BINDING ) break;
	}
	return 0;
}

static void
connection_init_log_prefix( Operation *op )
{
	if ( op->o_connid == (unsigned long)(-1) ) {
		snprintf( op->o_log_prefix, sizeof( op->o_log_prefix ),
			"conn=-1 op=%lu", op->o_opid );

	} else {
		snprintf( op->o_log_prefix, sizeof( op->o_log_prefix ),
			"conn=%lu op=%lu", op->o_connid, op->o_opid );
	}
}

static int connection_bind_cleanup_cb( Operation *op, SlapReply *rs )
{
	op->o_conn->c_sasl_bindop = NULL;

	ch_free( op->o_callback );
	op->o_callback = NULL;

	return SLAP_CB_CONTINUE;
}

static int connection_bind_cb( Operation *op, SlapReply *rs )
{
	ldap_pvt_thread_mutex_lock( &op->o_conn->c_mutex );
	op->o_conn->c_sasl_bind_in_progress =
		( rs->sr_err == LDAP_SASL_BIND_IN_PROGRESS );

	/* Moved here from bind.c due to ITS#4158 */
	op->o_conn->c_sasl_bindop = NULL;
	if ( op->orb_method == LDAP_AUTH_SASL ) {
		if( rs->sr_err == LDAP_SUCCESS ) {
			ber_dupbv(&op->o_conn->c_dn, &op->orb_edn);
			if( !BER_BVISEMPTY( &op->orb_edn ) ) {
				/* edn is always normalized already */
				ber_dupbv( &op->o_conn->c_ndn, &op->o_conn->c_dn );
			}
			op->o_tmpfree( op->orb_edn.bv_val, op->o_tmpmemctx );
			BER_BVZERO( &op->orb_edn );
			op->o_conn->c_authmech = op->o_conn->c_sasl_bind_mech;
			BER_BVZERO( &op->o_conn->c_sasl_bind_mech );

			op->o_conn->c_sasl_ssf = op->orb_ssf;
			if( op->orb_ssf > op->o_conn->c_ssf ) {
				op->o_conn->c_ssf = op->orb_ssf;
			}

			if( !BER_BVISEMPTY( &op->o_conn->c_dn ) ) {
				ber_len_t max = sockbuf_max_incoming_auth;
				ber_sockbuf_ctrl( op->o_conn->c_sb,
					LBER_SB_OPT_SET_MAX_INCOMING, &max );
			}

			/* log authorization identity */
			Debug( LDAP_DEBUG_STATS,
				"%s BIND dn=\"%s\" mech=%s bind_ssf=%d ssf=%d\n",
				op->o_log_prefix,
				BER_BVISNULL( &op->o_conn->c_dn ) ? "<empty>" : op->o_conn->c_dn.bv_val,
				op->o_conn->c_authmech.bv_val,
				op->orb_ssf, op->o_conn->c_ssf );

			Debug( LDAP_DEBUG_TRACE,
				"do_bind: SASL/%s bind: dn=\"%s\" bind_ssf=%d\n",
				op->o_conn->c_authmech.bv_val,
				BER_BVISNULL( &op->o_conn->c_dn ) ? "<empty>" : op->o_conn->c_dn.bv_val,
				op->orb_ssf );

		} else if ( rs->sr_err != LDAP_SASL_BIND_IN_PROGRESS ) {
			if ( !BER_BVISNULL( &op->o_conn->c_sasl_bind_mech ) ) {
				free( op->o_conn->c_sasl_bind_mech.bv_val );
				BER_BVZERO( &op->o_conn->c_sasl_bind_mech );
			}
		}
	}
	ldap_pvt_thread_mutex_unlock( &op->o_conn->c_mutex );

	ch_free( op->o_callback );
	op->o_callback = NULL;

	return SLAP_CB_CONTINUE;
}

static void connection_op_queue( Operation *op )
{
	ber_tag_t tag = op->o_tag;

	if (tag == LDAP_REQ_BIND) {
		slap_callback *sc = ch_calloc( 1, sizeof( slap_callback ));
		sc->sc_response = connection_bind_cb;
		sc->sc_cleanup = connection_bind_cleanup_cb;
		sc->sc_next = op->o_callback;
		op->o_callback = sc;
		op->o_conn->c_conn_state = SLAP_C_BINDING;
	}

	if (!op->o_dn.bv_len) {
		op->o_authz = op->o_conn->c_authz;
		if ( BER_BVISNULL( &op->o_conn->c_sasl_authz_dn )) {
			ber_dupbv( &op->o_dn, &op->o_conn->c_dn );
			ber_dupbv( &op->o_ndn, &op->o_conn->c_ndn );
		} else {
			ber_dupbv( &op->o_dn, &op->o_conn->c_sasl_authz_dn );
			ber_dupbv( &op->o_ndn, &op->o_conn->c_sasl_authz_dn );
		}
	}

	op->o_authtype = op->o_conn->c_authtype;
	ber_dupbv( &op->o_authmech, &op->o_conn->c_authmech );

	if (!op->o_protocol) {
		op->o_protocol = op->o_conn->c_protocol
			? op->o_conn->c_protocol : LDAP_VERSION3;
	}

	if (op->o_conn->c_conn_state == SLAP_C_INACTIVE &&
		op->o_protocol > LDAP_VERSION2)
	{
		op->o_conn->c_conn_state = SLAP_C_ACTIVE;
	}

	op->o_connid = op->o_conn->c_connid;
	connection_init_log_prefix( op );

	LDAP_STAILQ_INSERT_TAIL( &op->o_conn->c_ops, op, o_next );
}

static int connection_op_activate( Operation *op )
{
	int rc;

	connection_op_queue( op );

	rc = ldap_pvt_thread_pool_submit( &connection_pool,
		connection_operation, (void *) op );

	if ( rc != 0 ) {
		Debug( LDAP_DEBUG_ANY,
			"connection_op_activate: submit failed (%d) for conn=%lu\n",
			rc, op->o_connid );
		/* should move op to pending list */
	}

	return rc;
}

int connection_write(ber_socket_t s)
{
	Connection *c;
	Operation *op;
	int wantwrite;

	assert( connections != NULL );

	c = connection_get( s );
	if( c == NULL ) {
		Debug( LDAP_DEBUG_ANY,
			"connection_write(%ld): no connection!\n",
			(long)s );
		return -1;
	}

	slapd_clr_write( s, 0 );

#ifdef HAVE_TLS
	if ( c->c_is_tls && c->c_needs_tls_accept ) {
		connection_return( c );
		connection_read_activate( s );
		return 0;
	}
#endif

	c->c_n_write++;

	Debug( LDAP_DEBUG_TRACE,
		"connection_write(%d): waking output for id=%lu\n",
		s, c->c_connid );

	wantwrite = ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_NEEDS_WRITE, NULL );
	if ( ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_NEEDS_READ, NULL )) {
		/* don't wakeup twice */
		slapd_set_read( s, !wantwrite );
	}
	if ( wantwrite ) {
		slapd_set_write( s, 1 );
	}

	/* If there are ops pending because of a writewaiter,
	 * start one up.
	 */
	while ((op = LDAP_STAILQ_FIRST( &c->c_pending_ops )) != NULL) {
		if ( !c->c_writewaiter ) break;
		if ( c->c_n_ops_executing > connection_pool_max/2 ) break;

		LDAP_STAILQ_REMOVE_HEAD( &c->c_pending_ops, o_next );
		LDAP_STAILQ_NEXT(op, o_next) = NULL;

		/* pending operations should not be marked for abandonment */
		assert(!op->o_abandon);

		c->c_n_ops_pending--;
		c->c_n_ops_executing++;

		connection_op_activate( op );

		break;
	}

	connection_return( c );
	return 0;
}

void connection_write_resume( Connection *c )
{
	Operation *op;

	ldap_pvt_thread_mutex_lock( &c->c_mutex );
	/* If there are ops pending because of a writewaiter,
	 * start one up.
	 */
	while ((op = LDAP_STAILQ_FIRST( &c->c_pending_ops )) != NULL) {
		if ( c->c_n_ops_executing > connection_pool_max/2 ) break;

		LDAP_STAILQ_REMOVE_HEAD( &c->c_pending_ops, o_next );
		LDAP_STAILQ_NEXT(op, o_next) = NULL;

		/* pending operations should not be marked for abandonment */
		assert(!op->o_abandon);

		c->c_n_ops_pending--;
		c->c_n_ops_executing++;

		connection_op_activate( op );

		break;
	}

	connection_return( c );
}

#ifdef LDAP_SLAPI
typedef struct conn_fake_extblock {
	void *eb_conn;
	void *eb_op;
} conn_fake_extblock;

static void
connection_fake_destroy(
	void *key,
	void *data )
{
	Connection conn = {0};
	Operation op = {0};
	Opheader ohdr = {0};

	conn_fake_extblock *eb = data;

	op.o_hdr = &ohdr;
	op.o_hdr->oh_extensions = eb->eb_op;
	conn.c_extensions = eb->eb_conn;
	op.o_conn = &conn;
	conn.c_connid = -1;
	op.o_connid = -1;

	ber_memfree_x( eb, NULL );
	slapi_int_free_object_extensions( SLAPI_X_EXT_OPERATION, &op );
	slapi_int_free_object_extensions( SLAPI_X_EXT_CONNECTION, &conn );
}
#endif

void
connection_fake_init(
	Connection *conn,
	OperationBuffer *opbuf,
	void *ctx )
{
	connection_fake_init2( conn, opbuf, ctx, 1 );
}

void
operation_fake_init(
	Connection *conn,
	Operation *op,
	void *ctx,
	int newmem )
{
	/* set memory context */
	op->o_tmpmemctx = slap_sl_mem_create(SLAP_SLAB_SIZE, SLAP_SLAB_STACK, ctx,
		newmem );
	op->o_tmpmfuncs = &slap_sl_mfuncs;
	op->o_threadctx = ctx;
	op->o_tid = ldap_pvt_thread_pool_tid( ctx );

	op->o_counters = &slap_counters;
	op->o_conn = conn;
	op->o_connid = op->o_conn->c_connid;
	connection_init_log_prefix( op );
}


void
connection_fake_init2(
	Connection *conn,
	OperationBuffer *opbuf,
	void *ctx,
	int newmem )
{
	Operation *op = (Operation *) opbuf;

	conn->c_connid = -1;
	conn->c_conn_idx = -1;
	conn->c_send_ldap_result = slap_send_ldap_result;
	conn->c_send_search_entry = slap_send_search_entry;
	conn->c_send_search_reference = slap_send_search_reference;
	conn->c_send_ldap_extended = slap_send_ldap_extended;
	conn->c_send_ldap_intermediate = slap_send_ldap_intermediate;
	conn->c_listener = (Listener *)&dummy_list;
	conn->c_peer_domain = slap_empty_bv;
	conn->c_peer_name = slap_empty_bv;

	memset( opbuf, 0, sizeof( *opbuf ));
	op->o_hdr = &opbuf->ob_hdr;
	op->o_controls = opbuf->ob_controls;

	operation_fake_init( conn, op, ctx, newmem );

#ifdef LDAP_SLAPI
	if ( slapi_plugins_used ) {
		conn_fake_extblock *eb;
		void *ebx = NULL;

		/* Use thread keys to make sure these eventually get cleaned up */
		if ( ldap_pvt_thread_pool_getkey( ctx, (void *)connection_fake_init,
				&ebx, NULL )) {
			eb = ch_malloc( sizeof( *eb ));
			slapi_int_create_object_extensions( SLAPI_X_EXT_CONNECTION, conn );
			slapi_int_create_object_extensions( SLAPI_X_EXT_OPERATION, op );
			eb->eb_conn = conn->c_extensions;
			eb->eb_op = op->o_hdr->oh_extensions;
			ldap_pvt_thread_pool_setkey( ctx, (void *)connection_fake_init,
				eb, connection_fake_destroy, NULL, NULL );
		} else {
			eb = ebx;
			conn->c_extensions = eb->eb_conn;
			op->o_hdr->oh_extensions = eb->eb_op;
		}
	}
#endif /* LDAP_SLAPI */

	slap_op_time( &op->o_time, &op->o_tincr );
}

void
connection_assign_nextid( Connection *conn )
{
	ldap_pvt_thread_mutex_lock( &conn_nextid_mutex );
	conn->c_connid = conn_nextid++;
	ldap_pvt_thread_mutex_unlock( &conn_nextid_mutex );
}