]> git.sur5r.net Git - openldap/blobdiff - servers/slapd/connection.c
ITS#5469
[openldap] / servers / slapd / connection.c
index 4ac1bde3c04a4023b66cd71873ac65b6095262ee..742934113b1af7441130a5b5c0c401f01c2db79b 100644 (file)
@@ -1,7 +1,7 @@
 /* $OpenLDAP$ */
 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
  *
- * Copyright 1998-2004 The OpenLDAP Foundation.
+ * Copyright 1998-2008 The OpenLDAP Foundation.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -26,7 +26,9 @@
 #include "portable.h"
 
 #include <stdio.h>
+#ifdef HAVE_LIMITS_H
 #include <limits.h>
+#endif
 
 #include <ac/socket.h>
 #include <ac/errno.h>
@@ -48,10 +50,13 @@ static Connection *connections = NULL;
 static ldap_pvt_thread_mutex_t conn_nextid_mutex;
 static unsigned long conn_nextid = 0;
 
+static const char conn_lost_str[] = "connection lost";
+
 /* structure state (protected by connections_mutex) */
 #define SLAP_C_UNINITIALIZED   0x00    /* MUST BE ZERO (0) */
 #define SLAP_C_UNUSED                  0x01
 #define SLAP_C_USED                            0x02
+#define        SLAP_C_PENDING                  0x03
 
 /* connection state (protected by c_mutex ) */
 #define SLAP_C_INVALID                 0x00    /* MUST BE ZERO (0) */
@@ -78,10 +83,25 @@ connection_state2str( int state )
 
 static Connection* connection_get( ber_socket_t s );
 
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+
+typedef struct conn_readinfo {
+       Operation *op;
+       ldap_pvt_thread_start_t *func;
+       void *arg;
+       int nullop;
+} conn_readinfo;
+
+static int connection_input( Connection *c, conn_readinfo *cri );
+#else
 static int connection_input( Connection *c );
+#endif
 static void connection_close( Connection *c );
 
 static int connection_op_activate( Operation *op );
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+static void connection_op_queue( Operation *op );
+#endif
 static int connection_resched( Connection *conn );
 static void connection_abandon( Connection *conn );
 static void connection_destroy( Connection *c );
@@ -110,8 +130,8 @@ int connections_init(void)
        connections = (Connection *) ch_calloc( dtblsize, sizeof(Connection) );
 
        if( connections == NULL ) {
-               Debug( LDAP_DEBUG_ANY,
-                       "connections_init: allocation (%d*%ld) of connection array failed\n",
+               Debug( LDAP_DEBUG_ANY, "connections_init: "
+                       "allocation (%d*%ld) of connection array failed\n",
                        dtblsize, (long) sizeof(Connection), 0 );
                return -1;
        }
@@ -132,6 +152,7 @@ int connections_init(void)
 /*
  * Destroy connection management infrastructure.
  */
+
 int connections_destroy(void)
 {
        ber_socket_t i;
@@ -152,7 +173,8 @@ int connections_destroy(void)
                        ldap_pvt_thread_cond_destroy( &connections[i].c_write_cv );
 #ifdef LDAP_SLAPI
                        if ( slapi_plugins_used ) {
-                               slapi_int_free_object_extensions( SLAPI_X_EXT_CONNECTION, &connections[i] );
+                               slapi_int_free_object_extensions( SLAPI_X_EXT_CONNECTION,
+                                       &connections[i] );
                        }
 #endif
                }
@@ -173,30 +195,25 @@ int connections_shutdown(void)
 {
        ber_socket_t i;
 
-       ldap_pvt_thread_mutex_lock( &connections_mutex );
-
        for ( i = 0; i < dtblsize; i++ ) {
-               if( connections[i].c_struct_state != SLAP_C_USED ) {
-                       continue;
-               }
-               /* 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 );
-                       continue;
+               if( connections[i].c_struct_state != SLAP_C_UNINITIALIZED ) {
+                       ldap_pvt_thread_mutex_lock( &connections[i].c_mutex );
+                       if( connections[i].c_struct_state == SLAP_C_USED ) {
+
+                               /* 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 );
                }
-
-               ldap_pvt_thread_mutex_lock( &connections[i].c_mutex );
-
-               /* connections_mutex and c_mutex are locked */
-               connection_closing( &connections[i] );
-               connection_close( &connections[i] );
-
-               ldap_pvt_thread_mutex_unlock( &connections[i].c_mutex );
        }
 
-       ldap_pvt_thread_mutex_unlock( &connections_mutex );
-
        return 0;
 }
 
@@ -215,12 +232,13 @@ int connections_timeout_idle(time_t now)
        {
                /* Don't timeout a slow-running request or a persistent
                 * outbound connection */
-               if( c->c_n_ops_executing ||
-                       c->c_conn_state == SLAP_C_CLIENT ) continue;
+               if( c->c_n_ops_executing || c->c_conn_state == SLAP_C_CLIENT ) {
+                       continue;
+               }
 
                if( difftime( c->c_activitytime+global_idletimeout, now) < 0 ) {
                        /* close it */
-                       connection_closing( c );
+                       connection_closing( c, "idletimeout" );
                        connection_close( c );
                        i++;
                }
@@ -232,8 +250,6 @@ int connections_timeout_idle(time_t now)
 
 static Connection* connection_get( ber_socket_t s )
 {
-       /* connections_mutex should be locked by caller */
-
        Connection *c;
 
        Debug( LDAP_DEBUG_ARGS,
@@ -242,21 +258,22 @@ static Connection* connection_get( ber_socket_t s )
 
        assert( connections != NULL );
 
-       if(s == AC_SOCKET_INVALID) {
-               return NULL;
-       }
+       if(s == AC_SOCKET_INVALID) return NULL;
 
 #ifndef HAVE_WINSOCK
+       assert( s < dtblsize );
        c = &connections[s];
 
-       assert( c->c_struct_state != SLAP_C_UNINITIALIZED );
-
 #else
        c = NULL;
        {
                ber_socket_t i, sd;
 
+               ldap_pvt_thread_mutex_lock( &connections_mutex );
                for(i=0; i<dtblsize; i++) {
+                       if( connections[i].c_struct_state == SLAP_C_PENDING )
+                               continue;
+
                        if( connections[i].c_struct_state == SLAP_C_UNINITIALIZED ) {
                                assert( connections[i].c_conn_state == SLAP_C_INVALID );
                                assert( connections[i].c_sb == 0 );
@@ -281,6 +298,7 @@ static Connection* connection_get( ber_socket_t s )
                                break;
                        }
                }
+               ldap_pvt_thread_mutex_unlock( &connections_mutex );
        }
 #endif
 
@@ -289,7 +307,18 @@ static Connection* connection_get( ber_socket_t s )
 
                ldap_pvt_thread_mutex_lock( &c->c_mutex );
 
+               assert( c->c_struct_state != SLAP_C_UNINITIALIZED );
+
                ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_GET_FD, &sd );
+#ifdef HAVE_WINSOCK
+               /* Avoid race condition after releasing
+                * connections_mutex
+                */
+               if ( sd != s ) {
+                       ldap_pvt_thread_mutex_unlock( &c->c_mutex );
+                       return NULL;
+               }
+#endif
                if( c->c_struct_state != SLAP_C_USED ) {
                        /* connection must have been closed due to resched */
 
@@ -341,6 +370,7 @@ long connection_init(
 {
        unsigned long id;
        Connection *c;
+       int doinit = 0;
 
        assert( connections != NULL );
 
@@ -361,24 +391,29 @@ long connection_init(
        assert( s >= 0 );
 #ifndef HAVE_WINSOCK
        assert( s < dtblsize );
-#endif
-
-       ldap_pvt_thread_mutex_lock( &connections_mutex );
-
-#ifndef HAVE_WINSOCK
        c = &connections[s];
-
+       if( c->c_struct_state == SLAP_C_UNINITIALIZED ) {
+               doinit = 1;
+       } else {
+               assert( c->c_struct_state == SLAP_C_UNUSED );
+       }
 #else
        {
                ber_socket_t i;
                c = NULL;
 
+               ldap_pvt_thread_mutex_lock( &connections_mutex );
                for( i=0; i < dtblsize; i++) {
                        ber_socket_t    sd;
 
+                       if ( connections[i].c_struct_state == SLAP_C_PENDING )
+                               continue;
+
                        if( connections[i].c_struct_state == SLAP_C_UNINITIALIZED ) {
                                assert( connections[i].c_sb == 0 );
                                c = &connections[i];
+                               c->c_struct_state = SLAP_C_PENDING;
+                               doinit = 1;
                                break;
                        }
 
@@ -391,38 +426,33 @@ long connection_init(
                        if( connections[i].c_struct_state == SLAP_C_UNUSED ) {
                                assert( sd == AC_SOCKET_INVALID );
                                c = &connections[i];
+                               c->c_struct_state = SLAP_C_PENDING;
                                break;
                        }
 
-                       if( connections[i].c_conn_state == SLAP_C_CLIENT ) {
-                               continue;
-                       }
+                       if( connections[i].c_conn_state == SLAP_C_CLIENT ) continue;
 
                        assert( connections[i].c_struct_state == SLAP_C_USED );
                        assert( connections[i].c_conn_state != SLAP_C_INVALID );
                        assert( sd != AC_SOCKET_INVALID );
                }
+               ldap_pvt_thread_mutex_unlock( &connections_mutex );
 
                if( c == NULL ) {
                        Debug( LDAP_DEBUG_ANY,
                                "connection_init(%d): connection table full "
                                "(%d/%d)\n", s, i, dtblsize);
-                       ldap_pvt_thread_mutex_unlock( &connections_mutex );
                        return -1;
                }
        }
 #endif
 
-       assert( c != NULL );
-
-       if( c->c_struct_state == SLAP_C_UNINITIALIZED ) {
+       if( doinit ) {
                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;
-#ifdef LDAP_RES_INTERMEDIATE
                c->c_send_ldap_intermediate = slap_send_ldap_intermediate;
-#endif
 
                BER_BVZERO( &c->c_authmech );
                BER_BVZERO( &c->c_dn );
@@ -435,6 +465,12 @@ long connection_init(
                LDAP_STAILQ_INIT(&c->c_ops);
                LDAP_STAILQ_INIT(&c->c_pending_ops);
 
+#ifdef LDAP_X_TXN
+               c->c_txn = CONN_TXN_INACTIVE;
+               c->c_txn_backend = NULL;
+               LDAP_STAILQ_INIT(&c->c_txn_ops);
+#endif
+
                BER_BVZERO( &c->c_sasl_bind_mech );
                c->c_sasl_done = 0;
                c->c_sasl_authctx = NULL;
@@ -461,13 +497,10 @@ long connection_init(
                        slapi_int_create_object_extensions( SLAPI_X_EXT_CONNECTION, c );
                }
 #endif
-
-               c->c_struct_state = SLAP_C_UNUSED;
        }
 
        ldap_pvt_thread_mutex_lock( &c->c_mutex );
 
-       assert( c->c_struct_state == SLAP_C_UNUSED );
        assert( BER_BVISNULL( &c->c_authmech ) );
        assert( BER_BVISNULL( &c->c_dn ) );
        assert( BER_BVISNULL( &c->c_ndn ) );
@@ -476,6 +509,11 @@ long connection_init(
        assert( BER_BVISNULL( &c->c_peer_name ) );
        assert( LDAP_STAILQ_EMPTY(&c->c_ops) );
        assert( LDAP_STAILQ_EMPTY(&c->c_pending_ops) );
+#ifdef LDAP_X_TXN
+       assert( c->c_txn == CONN_TXN_INACTIVE );
+       assert( c->c_txn_backend == NULL );
+       assert( LDAP_STAILQ_EMPTY(&c->c_txn_ops) );
+#endif
        assert( BER_BVISNULL( &c->c_sasl_bind_mech ) );
        assert( c->c_sasl_done == 0 );
        assert( c->c_sasl_authctx == NULL );
@@ -490,9 +528,9 @@ long connection_init(
        if ( flags == CONN_IS_CLIENT ) {
                c->c_conn_state = SLAP_C_CLIENT;
                c->c_struct_state = SLAP_C_USED;
+               c->c_close_reason = "?";                        /* should never be needed */
                ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_SET_FD, &s );
                ldap_pvt_thread_mutex_unlock( &c->c_mutex );
-               ldap_pvt_thread_mutex_unlock( &connections_mutex );
 
                return 0;
        }
@@ -561,6 +599,7 @@ long connection_init(
 
        c->c_conn_state = SLAP_C_INACTIVE;
        c->c_struct_state = SLAP_C_USED;
+       c->c_close_reason = "?";                        /* should never be needed */
 
        c->c_ssf = c->c_transport_ssf = ssf;
        c->c_tls_ssf = 0;
@@ -578,8 +617,8 @@ long connection_init(
        slap_sasl_open( c, 0 );
        slap_sasl_external( c, ssf, authid );
 
+       slapd_add_internal( s, 1 );
        ldap_pvt_thread_mutex_unlock( &c->c_mutex );
-       ldap_pvt_thread_mutex_unlock( &connections_mutex );
 
        backend_connection_init(c);
 
@@ -596,39 +635,57 @@ void connection2anonymous( Connection *c )
                ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_SET_MAX_INCOMING, &max );
        }
 
-       if(c->c_authmech.bv_val != NULL ) {
-               free(c->c_authmech.bv_val);
+       if ( !BER_BVISNULL( &c->c_authmech ) ) {
+               ch_free(c->c_authmech.bv_val);
        }
        BER_BVZERO( &c->c_authmech );
 
-       if(c->c_dn.bv_val != NULL) {
-               free(c->c_dn.bv_val);
+       if ( !BER_BVISNULL( &c->c_dn ) ) {
+               ch_free(c->c_dn.bv_val);
        }
        BER_BVZERO( &c->c_dn );
-       if(c->c_ndn.bv_val != NULL) {
-               free(c->c_ndn.bv_val);
+
+       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 )
 {
-       /* note: connections_mutex should be locked by caller */
        ber_socket_t    sd;
        unsigned long   connid;
+       const char              *close_reason;
+       Sockbuf                 *sb;
 
        assert( connections != NULL );
        assert( c != NULL );
        assert( c->c_struct_state != SLAP_C_UNUSED );
        assert( c->c_conn_state != SLAP_C_INVALID );
        assert( LDAP_STAILQ_EMPTY(&c->c_ops) );
+       assert( LDAP_STAILQ_EMPTY(&c->c_pending_ops) );
+#ifdef LDAP_X_TXN
+       assert( c->c_txn == CONN_TXN_INACTIVE );
+       assert( c->c_txn_backend == NULL );
+       assert( LDAP_STAILQ_EMPTY(&c->c_txn_ops) );
+#endif
        assert( c->c_writewaiter == 0);
 
        /* only for stats (print -1 as "%lu" may give unexpected results ;) */
        connid = c->c_connid;
+       close_reason = c->c_close_reason;
+
+       ldap_pvt_thread_mutex_lock( &connections_mutex );
+       c->c_struct_state = SLAP_C_PENDING;
+       ldap_pvt_thread_mutex_unlock( &connections_mutex );
 
        backend_connection_destroy(c);
 
@@ -662,33 +719,41 @@ connection_destroy( Connection *c )
                c->c_currentber = NULL;
        }
 
-       ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_GET_FD, &sd );
-       if ( sd != AC_SOCKET_INVALID ) {
-               slapd_remove( sd, 1, 0 );
 
-               Statslog( LDAP_DEBUG_STATS,
-                       "conn=%lu fd=%ld closed\n",
-                       connid, (long) sd, 0, 0, 0 );
+#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
 
-       ber_sockbuf_free( c->c_sb );
+       c->c_conn_state = SLAP_C_INVALID;
+       c->c_struct_state = SLAP_C_UNUSED;
+       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->c_struct_state = SLAP_C_UNUSED;
+       ber_sockbuf_ctrl( sb, LBER_SB_OPT_GET_FD, &sd );
 
-#ifdef LDAP_SLAPI
-       /* call destructors, then constructors; avoids unnecessary allocation */
-       if ( slapi_plugins_used ) {
-               slapi_int_clear_object_extensions( SLAPI_X_EXT_CONNECTION, c );
+       /* 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 ) {
+                       Statslog( LDAP_DEBUG_STATS, "conn=%lu fd=%ld closed\n",
+                               connid, (long) sd, 0, 0, 0 );
+               } else {
+                       Statslog( LDAP_DEBUG_STATS, "conn=%lu fd=%ld closed (%s)\n",
+                               connid, (long) sd, close_reason, 0, 0 );
+               }
        }
-#endif
 }
 
 int connection_state_closing( Connection *c )
@@ -718,6 +783,7 @@ static void connection_abandon( Connection *c )
        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 ) {
                next = LDAP_STAILQ_NEXT( o, o_next );
                op.orn_msgid = o->o_msgid;
@@ -726,6 +792,19 @@ static void connection_abandon( Connection *c )
                frontendDB->be_abandon( &op, &rs );
        }
 
+#ifdef LDAP_X_TXN
+       /* 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 );
+       }
+
+       /* clear transaction */
+       c->c_txn_backend = NULL;
+       c->c_txn = CONN_TXN_INACTIVE;
+#endif
+
        /* remove pending operations */
        while ( (o = LDAP_STAILQ_FIRST( &c->c_pending_ops )) != NULL) {
                LDAP_STAILQ_REMOVE_HEAD( &c->c_pending_ops, o_next );
@@ -734,7 +813,7 @@ static void connection_abandon( Connection *c )
        }
 }
 
-void connection_closing( Connection *c )
+void connection_closing( Connection *c, const char *why )
 {
        assert( connections != NULL );
        assert( c != NULL );
@@ -752,32 +831,63 @@ void connection_closing( Connection *c )
                        c->c_connid, sd, 0 );
                /* 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( sd, 1 );
+               slapd_clr_read( sd, 0 );
 
                /* abandon active operations */
                connection_abandon( c );
 
                /* wake write blocked operations */
-               slapd_clr_write( sd, 1 );
-               ldap_pvt_thread_cond_signal( &c->c_write_cv );
+               if ( c->c_writewaiter ) {
+                       ldap_pvt_thread_cond_signal( &c->c_write_cv );
+                       /* ITS#4667 this may allow another thread to drop into
+                        * connection_resched / connection_close before we
+                        * finish, but that's OK.
+                        */
+                       slapd_clr_write( sd, 1 );
+                       ldap_pvt_thread_mutex_unlock( &c->c_mutex );
+                       ldap_pvt_thread_mutex_lock( &c->c_write_mutex );
+                       ldap_pvt_thread_mutex_lock( &c->c_mutex );
+                       ldap_pvt_thread_mutex_unlock( &c->c_write_mutex );
+               } else {
+                       slapd_clr_write( sd, 1 );
+               }
+
+       } 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 )
+static void
+connection_close( Connection *c )
 {
-       ber_socket_t    sd;
+       ber_socket_t    sd = AC_SOCKET_INVALID;
 
        assert( connections != NULL );
        assert( c != NULL );
+
+       /* ITS#4667 we may have gotten here twice */
+       if ( c->c_conn_state == SLAP_C_INVALID )
+               return;
+
        assert( c->c_struct_state == SLAP_C_USED );
        assert( c->c_conn_state == SLAP_C_CLOSING );
 
-       /* note: connections_mutex and c_mutex should be locked by caller */
+       /* NOTE: c_mutex should be locked by caller */
 
-       ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_GET_FD, &sd );
-       if( !LDAP_STAILQ_EMPTY(&c->c_ops) ) {
+       /* NOTE: don't get the file descriptor if not needed */
+#ifdef LDAP_DEBUG
+       if ( slap_debug & LDAP_DEBUG_TRACE ) {
+               ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_GET_FD, &sd );
+       }
+#endif /* LDAP_DEBUG */
+
+       if ( !LDAP_STAILQ_EMPTY(&c->c_ops) ||
+               !LDAP_STAILQ_EMPTY(&c->c_pending_ops) )
+       {
                Debug( LDAP_DEBUG_TRACE,
                        "connection_close: deferring conn=%lu sd=%d\n",
                        c->c_connid, sd, 0 );
@@ -786,6 +896,7 @@ static void connection_close( Connection *c )
 
        Debug( LDAP_DEBUG_TRACE, "connection_close: conn=%lu sd=%d\n",
                c->c_connid, sd, 0 );
+
        connection_destroy( c );
 }
 
@@ -794,11 +905,11 @@ unsigned long connections_nextid(void)
        unsigned long id;
        assert( connections != NULL );
 
-       ldap_pvt_thread_mutex_lock( &connections_mutex );
+       ldap_pvt_thread_mutex_lock( &conn_nextid_mutex );
 
        id = conn_nextid;
 
-       ldap_pvt_thread_mutex_unlock( &connections_mutex );
+       ldap_pvt_thread_mutex_unlock( &conn_nextid_mutex );
 
        return id;
 }
@@ -809,8 +920,12 @@ Connection* connection_first( ber_socket_t *index )
        assert( index != NULL );
 
        ldap_pvt_thread_mutex_lock( &connections_mutex );
-
-       *index = 0;
+       for( *index = 0; *index < dtblsize; (*index)++) {
+               if( connections[*index].c_struct_state != SLAP_C_UNINITIALIZED ) {
+                       break;
+               }
+       }
+       ldap_pvt_thread_mutex_unlock( &connections_mutex );
 
        return connection_next(NULL, index);
 }
@@ -821,36 +936,47 @@ Connection* connection_next( Connection *c, ber_socket_t *index )
        assert( index != NULL );
        assert( *index <= dtblsize );
 
-       if( c != NULL ) {
-               ldap_pvt_thread_mutex_unlock( &c->c_mutex );
-       }
+       if( c != NULL ) ldap_pvt_thread_mutex_unlock( &c->c_mutex );
 
        c = NULL;
 
+       ldap_pvt_thread_mutex_lock( &connections_mutex );
        for(; *index < dtblsize; (*index)++) {
+               int c_struct;
                if( connections[*index].c_struct_state == SLAP_C_UNINITIALIZED ) {
                        assert( connections[*index].c_conn_state == SLAP_C_INVALID );
-#ifndef HAVE_WINSOCK
-                       continue;
-#else
+#ifdef HAVE_WINSOCK
                        break;
+#else
+                       continue;
 #endif
                }
 
                if( connections[*index].c_struct_state == SLAP_C_USED ) {
                        assert( connections[*index].c_conn_state != SLAP_C_INVALID );
                        c = &connections[(*index)++];
+                       if ( ldap_pvt_thread_mutex_trylock( &c->c_mutex )) {
+                               /* avoid deadlock */
+                               ldap_pvt_thread_mutex_unlock( &connections_mutex );
+                               ldap_pvt_thread_mutex_lock( &c->c_mutex );
+                               ldap_pvt_thread_mutex_lock( &connections_mutex );
+                               if ( c->c_struct_state != SLAP_C_USED ) {
+                                       ldap_pvt_thread_mutex_unlock( &c->c_mutex );
+                                       c = NULL;
+                                       continue;
+                               }
+                       }
                        break;
                }
 
-               assert( connections[*index].c_struct_state == SLAP_C_UNUSED );
+               c_struct = connections[*index].c_struct_state;
+               if ( c_struct == SLAP_C_PENDING )
+                       continue;
+               assert( c_struct == SLAP_C_UNUSED );
                assert( connections[*index].c_conn_state == SLAP_C_INVALID );
        }
 
-       if( c != NULL ) {
-               ldap_pvt_thread_mutex_lock( &c->c_mutex );
-       }
-
+       ldap_pvt_thread_mutex_unlock( &connections_mutex );
        return c;
 }
 
@@ -858,11 +984,7 @@ void connection_done( Connection *c )
 {
        assert( connections != NULL );
 
-       if( c != NULL ) {
-               ldap_pvt_thread_mutex_unlock( &c->c_mutex );
-       }
-
-       ldap_pvt_thread_mutex_unlock( &connections_mutex );
+       if( c != NULL ) ldap_pvt_thread_mutex_unlock( &c->c_mutex );
 }
 
 /*
@@ -887,10 +1009,32 @@ void connection_done( Connection *c )
                ldap_pvt_thread_mutex_unlock( &slap_counters.sc_ops_mutex ); \
        } while (0)
 #else /* !SLAPD_MONITOR */
-#define INCR_OP_INITIATED(index) 
-#define INCR_OP_COMPLETED(index) 
+#define INCR_OP_INITIATED(index) do { } while (0)
+#define INCR_OP_COMPLETED(index) \
+       do { \
+               ldap_pvt_thread_mutex_lock( &slap_counters.sc_ops_mutex ); \
+               ldap_pvt_mp_add_ulong(slap_counters.sc_ops_completed, 1); \
+               ldap_pvt_thread_mutex_unlock( &slap_counters.sc_ops_mutex ); \
+       } while (0)
 #endif /* !SLAPD_MONITOR */
 
+/*
+ * NOTE: keep in sync with enum in slapd.h
+ */
+static BI_op_func *opfun[] = {
+       do_bind,
+       do_unbind,
+       do_add,
+       do_delete,
+       do_modrdn,
+       do_modify,
+       do_compare,
+       do_search,
+       do_abandon,
+       do_extended,
+       NULL
+};
+
 static void *
 connection_operation( void *ctx, void *arg_v )
 {
@@ -898,9 +1042,7 @@ connection_operation( void *ctx, void *arg_v )
        Operation *op = arg_v;
        SlapReply rs = {REP_RESULT};
        ber_tag_t tag = op->o_tag;
-#ifdef SLAPD_MONITOR
-       ber_tag_t oldtag = tag;
-#endif /* SLAPD_MONITOR */
+       slap_op_t opidx = SLAP_OP_LAST;
        Connection *conn = op->o_conn;
        void *memctx = NULL;
        void *memctx_null = NULL;
@@ -912,13 +1054,16 @@ connection_operation( void *ctx, void *arg_v )
        ldap_pvt_thread_mutex_unlock( &slap_counters.sc_ops_mutex );
 
        op->o_threadctx = ctx;
+#ifdef LDAP_DEVEL
+       op->o_tid = ldap_pvt_thread_pool_tid( ctx );
+#endif /* LDAP_DEVEL */
 
        switch ( tag ) {
        case LDAP_REQ_BIND:
        case LDAP_REQ_UNBIND:
        case LDAP_REQ_ADD:
        case LDAP_REQ_DELETE:
-       case LDAP_REQ_MODRDN:
+       case LDAP_REQ_MODDN:
        case LDAP_REQ_MODIFY:
        case LDAP_REQ_COMPARE:
        case LDAP_REQ_SEARCH:
@@ -947,6 +1092,20 @@ connection_operation( void *ctx, void *arg_v )
                goto operations_error;
        }
 
+#ifdef LDAP_X_TXN
+       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
+#endif
+       {
        /* We can use Thread-Local storage for most mallocs. We can
         * also use TL for ber parsing, but not on Add or Modify.
         */
@@ -966,113 +1125,32 @@ connection_operation( void *ctx, void *arg_v )
                 */
                ber_set_option( op->o_ber, LBER_OPT_BER_MEMCTX, &memctx );
        }
-
-       switch ( tag ) {
-       case LDAP_REQ_BIND:
-               INCR_OP_INITIATED(SLAP_OP_BIND);
-               rc = do_bind( op, &rs );
-               break;
-
-       case LDAP_REQ_UNBIND:
-               INCR_OP_INITIATED(SLAP_OP_UNBIND);
-               rc = do_unbind( op, &rs );
-               break;
-
-       case LDAP_REQ_ADD:
-               INCR_OP_INITIATED(SLAP_OP_ADD);
-               rc = do_add( op, &rs );
-               break;
-
-       case LDAP_REQ_DELETE:
-               INCR_OP_INITIATED(SLAP_OP_DELETE);
-               rc = do_delete( op, &rs );
-               break;
-
-       case LDAP_REQ_MODRDN:
-               INCR_OP_INITIATED(SLAP_OP_MODRDN);
-               rc = do_modrdn( op, &rs );
-               break;
-
-       case LDAP_REQ_MODIFY:
-               INCR_OP_INITIATED(SLAP_OP_MODIFY);
-               rc = do_modify( op, &rs );
-               break;
-
-       case LDAP_REQ_COMPARE:
-               INCR_OP_INITIATED(SLAP_OP_COMPARE);
-               rc = do_compare( op, &rs );
-               break;
-
-       case LDAP_REQ_SEARCH:
-               INCR_OP_INITIATED(SLAP_OP_SEARCH);
-               rc = do_search( op, &rs );
-               break;
-
-       case LDAP_REQ_ABANDON:
-               INCR_OP_INITIATED(SLAP_OP_ABANDON);
-               rc = do_abandon( op, &rs );
-               break;
-
-       case LDAP_REQ_EXTENDED:
-               INCR_OP_INITIATED(SLAP_OP_EXTENDED);
-               rc = do_extended( op, &rs );
-               break;
-
-       default:
-               /* not reachable */
-               assert( 0 );
        }
 
+       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;
+       if ( rc == SLAPD_DISCONNECT ) {
+               tag = LBER_ERROR;
 
-#ifdef SLAPD_MONITOR
-       switch (oldtag) {
-       case LDAP_REQ_BIND:
-               INCR_OP_COMPLETED(SLAP_OP_BIND);
-               break;
-       case LDAP_REQ_UNBIND:
-               INCR_OP_COMPLETED(SLAP_OP_UNBIND);
-               break;
-       case LDAP_REQ_ADD:
-               INCR_OP_COMPLETED(SLAP_OP_ADD);
-               break;
-       case LDAP_REQ_DELETE:
-               INCR_OP_COMPLETED(SLAP_OP_DELETE);
-               break;
-       case LDAP_REQ_MODDN:
-               INCR_OP_COMPLETED(SLAP_OP_MODRDN);
-               break;
-       case LDAP_REQ_MODIFY:
-               INCR_OP_COMPLETED(SLAP_OP_MODIFY);
-               break;
-       case LDAP_REQ_COMPARE:
-               INCR_OP_COMPLETED(SLAP_OP_COMPARE);
-               break;
-       case LDAP_REQ_SEARCH:
-               INCR_OP_COMPLETED(SLAP_OP_SEARCH);
-               break;
-       case LDAP_REQ_ABANDON:
-               INCR_OP_COMPLETED(SLAP_OP_ABANDON);
-               break;
-       case LDAP_REQ_EXTENDED:
-               INCR_OP_COMPLETED(SLAP_OP_EXTENDED);
-               break;
-       default:
-               /* this is reachable */
-#if 0
-               /* not reachable */
-               assert( 0 )
-#endif
-                       ;
+       } else if ( opidx != SLAP_OP_LAST ) {
+               /* increment completed operations count 
+                * only if operation was initiated
+                * and rc != SLAPD_DISCONNECT */
+               INCR_OP_COMPLETED( opidx );
        }
-#endif /* SLAPD_MONITOR */
-
-       ldap_pvt_thread_mutex_unlock( &slap_counters.sc_ops_mutex );
 
        if ( op->o_cancel == SLAP_CANCEL_REQ ) {
-               op->o_cancel = LDAP_TOO_LATE;
+               if ( rc == SLAPD_ABANDON ) {
+                       op->o_cancel = SLAP_CANCEL_ACK;
+               } else {
+                       op->o_cancel = LDAP_TOO_LATE;
+               }
        }
+
        while ( op->o_cancel != SLAP_CANCEL_NONE &&
                op->o_cancel != SLAP_CANCEL_DONE )
        {
@@ -1083,42 +1161,19 @@ operations_error:
 
        ber_set_option( op->o_ber, LBER_OPT_BER_MEMCTX, &memctx_null );
 
-#if 0  /* DELETE ME */
-       if ( op->o_cancel != SLAP_CANCEL_ACK &&
-               ( op->o_sync_mode & SLAP_SYNC_PERSIST ) )
-       {
-               slap_sl_mem_detach( ctx, memctx );
-       } else if ( op->o_sync_slog_size != -1 ) {
-               slap_sl_mem_detach( ctx, memctx );
-               LDAP_STAILQ_REMOVE( &conn->c_ops, op, slap_op, o_next);
-               LDAP_STAILQ_NEXT(op, o_next) = NULL;
-               conn->c_n_ops_executing--;
-               conn->c_n_ops_completed++;
-
-       } else
-#endif
-       {
-               LDAP_STAILQ_REMOVE( &conn->c_ops, op, slap_op, o_next);
-               LDAP_STAILQ_NEXT(op, o_next) = NULL;
-               slap_op_free( op );
-               conn->c_n_ops_executing--;
-               conn->c_n_ops_completed++;
-       }
+       LDAP_STAILQ_REMOVE( &conn->c_ops, op, slap_op, o_next);
+       LDAP_STAILQ_NEXT(op, o_next) = NULL;
+       slap_op_free( op );
+       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 );
+               connection_closing( conn,
+                       tag == LDAP_REQ_UNBIND ? NULL : "operations error" );
                break;
-
-       case LDAP_REQ_BIND:
-               conn->c_sasl_bind_in_progress =
-                       rc == LDAP_SASL_BIND_IN_PROGRESS ? 1 : 0;
-
-               if( conn->c_conn_state == SLAP_C_BINDING) {
-                       conn->c_conn_state = SLAP_C_ACTIVE;
-               }
        }
 
        connection_resched( conn );
@@ -1143,9 +1198,10 @@ int connection_client_setup(
        c = connection_get( s );
        c->c_clientfunc = func;
        c->c_clientarg = arg;
-       connection_return( c );
+
        slapd_add_internal( s, 0 );
        slapd_set_read( s, 1 );
+       connection_return( c );
        return 0;
 }
 
@@ -1159,6 +1215,7 @@ void connection_client_stop(
        ber_socket_t s )
 {
        Connection *c;
+       Sockbuf *sb;
 
        /* get (locked) connection */
        c = connection_get( s );
@@ -1168,19 +1225,85 @@ void connection_client_stop(
        c->c_listener = NULL;
        c->c_conn_state = SLAP_C_INVALID;
        c->c_struct_state = SLAP_C_UNUSED;
+       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 );
+       }
+       slapd_remove( s, sb, 0, 1, 0 );
+
        connection_return( c );
-       slapd_remove( s, 0, 1 );
 }
 
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+
+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, 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
+        */
+       if( ( rc = connection_read( s, &cri ) ) < 0 ) {
+               Debug( LDAP_DEBUG_CONNS, "connection_read(%d) error\n", s, 0, 0 );
+               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, 0 );
+       }
+
+       return rc;
+}
+#endif
+
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+static int
+connection_read( ber_socket_t s, conn_readinfo *cri )
+#else
 int connection_read(ber_socket_t s)
+#endif
 {
        int rc = 0;
        Connection *c;
 
        assert( connections != NULL );
 
-       ldap_pvt_thread_mutex_lock( &connections_mutex );
-
        /* get (locked) connection */
        c = connection_get( s );
 
@@ -1188,9 +1311,7 @@ int connection_read(ber_socket_t s)
                Debug( LDAP_DEBUG_ANY,
                        "connection_read(%ld): no connection!\n",
                        (long) s, 0, 0 );
-               slapd_remove(s, 1, 0);
 
-               ldap_pvt_thread_mutex_unlock( &connections_mutex );
                return -1;
        }
 
@@ -1201,16 +1322,20 @@ int connection_read(ber_socket_t s)
                        "connection_read(%d): closing, ignoring input for id=%lu\n",
                        s, c->c_connid, 0 );
                connection_return( c );
-               ldap_pvt_thread_mutex_unlock( &connections_mutex );
                return 0;
        }
 
        if ( c->c_conn_state == SLAP_C_CLIENT ) {
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+               cri->func = c->c_clientfunc;
+               cri->arg = c->c_clientarg;
+               /* read should already be cleared */
+#else
                slapd_clr_read( s, 0 );
                ldap_pvt_thread_pool_submit( &connection_pool,
                        c->c_clientfunc, c->c_clientarg );
+#endif
                connection_return( c );
-               ldap_pvt_thread_mutex_unlock( &connections_mutex );
                return 0;
        }
 
@@ -1222,34 +1347,17 @@ int connection_read(ber_socket_t s)
        if ( c->c_is_tls && c->c_needs_tls_accept ) {
                rc = ldap_pvt_tls_accept( c->c_sb, slap_tls_ctx );
                if ( rc < 0 ) {
-#if 0 /* required by next #if 0 */
-                       struct timeval tv;
-                       fd_set rfd;
-#endif
-
                        Debug( LDAP_DEBUG_TRACE,
-                               "connection_read(%d): TLS accept error "
+                               "connection_read(%d): TLS accept failure "
                                "error=%d id=%lu, closing\n",
                                s, rc, c->c_connid );
-                       c->c_needs_tls_accept = 0;
-                       /* connections_mutex and c_mutex are locked */
-                       connection_closing( c );
 
-#if 0
-                       /* Drain input before close, to allow SSL error codes
-                        * to propagate to client. */
-                       FD_ZERO(&rfd);
-                       FD_SET(s, &rfd);
-                       for (rc=1; rc>0;) {
-                               tv.tv_sec = 1;
-                               tv.tv_usec = 0;
-                               rc = select(s+1, &rfd, NULL, NULL, &tv);
-                               if (rc == 1) {
-                                       ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_DRAIN, NULL);
-                               }
-                       }
-#endif
+                       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;
@@ -1271,16 +1379,21 @@ int connection_read(ber_socket_t s)
                                        "unable to get TLS client DN, error=%d id=%lu\n",
                                        s, rc, c->c_connid );
                        }
+                       Statslog( LDAP_DEBUG_STATS,
+                               "conn=%lu fd=%d TLS established tls_ssf=%u ssf=%u\n",
+                           c->c_connid, (int) s, c->c_tls_ssf, c->c_ssf, 0 );
                        slap_sasl_external( c, c->c_tls_ssf, &authid );
                        if ( authid.bv_val ) free( authid.bv_val );
                }
 
                /* if success and data is ready, fall thru to data input loop */
-               if( rc != 0 ||
-                       !ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_DATA_READY, NULL ) )
+               if( !ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_DATA_READY, NULL ) )
                {
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+                       slapd_set_read( s, 1 );
+#endif
+
                        connection_return( c );
-                       ldap_pvt_thread_mutex_unlock( &connections_mutex );
                        return 0;
                }
        }
@@ -1290,25 +1403,27 @@ int connection_read(ber_socket_t s)
        if ( c->c_sasl_layers ) {
                /* If previous layer is not removed yet, give up for now */
                if ( !c->c_sasl_sockctx ) {
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+                       slapd_set_read( s, 1 );
+#endif
+
                        connection_return( c );
-                       ldap_pvt_thread_mutex_unlock( &connections_mutex );
                        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 );
-                       /* connections_mutex and c_mutex are locked */
-                       connection_closing( c );
+
+                       /* c_mutex is locked */
+                       connection_closing( c, "SASL layer install failure" );
                        connection_close( c );
                        connection_return( c );
-                       ldap_pvt_thread_mutex_unlock( &connections_mutex );
                        return 0;
                }
        }
@@ -1319,7 +1434,11 @@ int connection_read(ber_socket_t s)
 
        do {
                /* How do we do this without getting into a busy loop ? */
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+               rc = connection_input( c, cri );
+#else
                rc = connection_input( c );
+#endif
        }
 #ifdef DATA_READY_LOOP
        while( !rc && ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_DATA_READY, NULL ));
@@ -1330,17 +1449,24 @@ int connection_read(ber_socket_t s)
 #endif
 
        if( rc < 0 ) {
-               Debug( LDAP_DEBUG_TRACE,
+               Debug( LDAP_DEBUG_CONNS,
                        "connection_read(%d): input error=%d id=%lu, closing.\n",
                        s, rc, c->c_connid );
-               /* connections_mutex and c_mutex are locked */
-               connection_closing( c );
+
+               /* c_mutex is locked */
+               connection_closing( c, conn_lost_str );
                connection_close( c );
                connection_return( c );
-               ldap_pvt_thread_mutex_unlock( &connections_mutex );
                return 0;
        }
 
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+       if ( ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_NEEDS_WRITE, NULL ) ) {
+               slapd_set_write( s, 0 );
+       }
+
+       slapd_set_read( s, 1 );
+#else
        if ( ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_NEEDS_READ, NULL ) ) {
                slapd_set_read( s, 1 );
        }
@@ -1348,15 +1474,19 @@ int connection_read(ber_socket_t s)
        if ( ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_NEEDS_WRITE, NULL ) ) {
                slapd_set_write( s, 1 );
        }
+#endif
 
        connection_return( c );
-       ldap_pvt_thread_mutex_unlock( &connections_mutex );
+
        return 0;
 }
 
 static int
-connection_input(
-       Connection *conn )
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+connection_input( Connection *conn , conn_readinfo *cri )
+#else
+connection_input( Connection *conn )
+#endif
 {
        Operation *op;
        ber_tag_t       tag;
@@ -1377,15 +1507,15 @@ connection_input(
                return -1;
        }
 
-       errno = 0;
+       sock_errset(0);
 
 #ifdef LDAP_CONNECTIONLESS
        if ( conn->c_is_udp ) {
-               char    peername[sizeof("IP=255.255.255.255:65336")];
-               len = ber_int_sb_read(conn->c_sb, &peeraddr,
-                       sizeof(struct sockaddr));
-               if (len != sizeof(struct sockaddr))
-                       return 1;
+               char peername[sizeof("IP=255.255.255.255:65336")];
+
+               len = ber_int_sb_read(conn->c_sb, &peeraddr, sizeof(struct sockaddr));
+               if (len != sizeof(struct sockaddr)) return 1;
+
                sprintf( peername, "IP=%s:%d",
                        inet_ntoa( peeraddr.sa_in_addr.sin_addr ),
                        (unsigned) ntohs( peeraddr.sa_in_addr.sin_port ) );
@@ -1394,18 +1524,19 @@ connection_input(
                        conn->c_connid, peername, conn->c_sock_name.bv_val, 0, 0 );
        }
 #endif
+
        tag = ber_get_next( conn->c_sb, &len, conn->c_currentber );
        if ( tag != LDAP_TAG_MESSAGE ) {
-               int err = errno;
+               int err = sock_errno();
                ber_socket_t    sd;
 
                ber_sockbuf_ctrl( conn->c_sb, LBER_SB_OPT_GET_FD, &sd );
 
+               if ( err != EWOULDBLOCK && err != EAGAIN ) {
+                       /* log, close and send error */
                Debug( LDAP_DEBUG_TRACE,
                        "ber_get_next on fd %d failed errno=%d (%s)\n",
                        sd, err, sock_errstr(err) );
-               if ( err != EWOULDBLOCK && err != EAGAIN ) {
-                       /* log, close and send error */
                        ber_free( conn->c_currentber, 1 );
                        conn->c_currentber = NULL;
 
@@ -1419,16 +1550,14 @@ connection_input(
 
        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, 0, 0 );
+               Debug( LDAP_DEBUG_ANY, "ber_get_int returns 0x%lx\n", tag, 0, 0 );
                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, 0, 0 );
+               Debug( LDAP_DEBUG_ANY, "ber_peek_tag returns 0x%lx\n", tag, 0, 0 );
                ber_free( ber, 1 );
 
                return -1;
@@ -1447,8 +1576,9 @@ connection_input(
                }
        }
 #endif
+
        if(tag == LDAP_REQ_BIND) {
-               /* immediately abandon all exiting operations upon BIND */
+               /* immediately abandon all existing operations upon BIND */
                connection_abandon( conn );
        }
 
@@ -1457,7 +1587,8 @@ connection_input(
        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 ) );
+               memset( &conn->c_pagedresults_state, 0,
+                       sizeof( conn->c_pagedresults_state ) );
        }
 
        op->o_res_ber = NULL;
@@ -1498,16 +1629,32 @@ connection_input(
         * already pending ops, let them go first.  Abandon operations
         * get exceptions to some, but not all, cases.
         */
-       if (tag != LDAP_REQ_ABANDON && conn->c_conn_state == SLAP_C_CLOSING) {
-               defer = "closing";
-       } else if (tag != LDAP_REQ_ABANDON && conn->c_writewaiter) {
-               defer = "awaiting write";
-       } else if (conn->c_n_ops_executing >= connection_pool_max/2) {
-               defer = "too many executing";
-       } else if (conn->c_conn_state == SLAP_C_BINDING) {
-               defer = "binding";
-       } else if (tag != LDAP_REQ_ABANDON && conn->c_n_ops_pending) {
-               defer = "pending operations";
+       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 ) {
@@ -1520,14 +1667,33 @@ connection_input(
                        conn->c_connid, defer, 0 );
                conn->c_n_ops_pending++;
                LDAP_STAILQ_INSERT_TAIL( &conn->c_pending_ops, op, o_next );
-               if ( conn->c_n_ops_pending > max ) {
-                       rc = -1;
-               } else {
-                       rc = 1;
-               }
+               rc = ( conn->c_n_ops_pending > max ) ? -1 : 0;
+
        } else {
                conn->c_n_ops_executing++;
+
+#ifdef SLAP_LIGHTWEIGHT_DISPATCHER
+               /*
+                * 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 );
+               }
+#else
                connection_op_activate( op );
+#endif
        }
 
 #ifdef NO_THREADS
@@ -1536,8 +1702,8 @@ connection_input(
                return 1;
        }
 #endif
-       assert( conn->c_struct_state == SLAP_C_USED );
 
+       assert( conn->c_struct_state == SLAP_C_USED );
        return rc;
 }
 
@@ -1546,54 +1712,31 @@ connection_resched( Connection *conn )
 {
        Operation *op;
 
+       if( conn->c_writewaiter )
+               return 0;
+
        if( conn->c_conn_state == SLAP_C_CLOSING ) {
-               int rc;
                ber_socket_t    sd;
                ber_sockbuf_ctrl( conn->c_sb, LBER_SB_OPT_GET_FD, &sd );
 
-               /* use trylock to avoid possible deadlock */
-               rc = ldap_pvt_thread_mutex_trylock( &connections_mutex );
-
-               if( rc ) {
-                       Debug( LDAP_DEBUG_TRACE,
-                               "connection_resched: reaquiring locks conn=%lu sd=%d\n",
-                               conn->c_connid, sd, 0 );
-                       /*
-                        * reaquire locks in the right order...
-                        * this may allow another thread to close this connection,
-                        * so recheck state below.
-                        */
-                       ldap_pvt_thread_mutex_unlock( &conn->c_mutex );
-                       ldap_pvt_thread_mutex_lock( &connections_mutex );
-                       ldap_pvt_thread_mutex_lock( &conn->c_mutex );
-               }
-
-               if( conn->c_conn_state != SLAP_C_CLOSING ) {
-                       Debug( LDAP_DEBUG_TRACE, "connection_resched: "
-                               "closed by other thread conn=%lu sd=%d\n",
-                               conn->c_connid, sd, 0 );
-               } else {
-                       Debug( LDAP_DEBUG_TRACE, "connection_resched: "
-                               "attempting closing conn=%lu sd=%d\n",
-                               conn->c_connid, sd, 0 );
-                       connection_close( conn );
-               }
-
-               ldap_pvt_thread_mutex_unlock( &connections_mutex );
+               Debug( LDAP_DEBUG_TRACE, "connection_resched: "
+                       "attempting closing conn=%lu sd=%d\n",
+                       conn->c_connid, sd, 0 );
+               connection_close( conn );
                return 0;
        }
 
-       if( conn->c_conn_state != SLAP_C_ACTIVE || conn->c_writewaiter ) {
+       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;
-               }
+               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);
 
@@ -1602,9 +1745,7 @@ connection_resched( Connection *conn )
 
                connection_op_activate( op );
 
-               if ( conn->c_conn_state == SLAP_C_BINDING ) {
-                       break;
-               }
+               if ( conn->c_conn_state == SLAP_C_BINDING ) break;
        }
        return 0;
 }
@@ -1614,28 +1755,110 @@ 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 );
+                       "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 );
+                       "conn=%lu op=%lu", op->o_connid, op->o_opid );
        }
 }
 
-static int connection_op_activate( Operation *op )
+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 );
+       if ( op->o_conn->c_conn_state == SLAP_C_BINDING )
+               op->o_conn->c_conn_state = SLAP_C_ACTIVE;
+       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 */
+                       Statslog( LDAP_DEBUG_STATS,
+                               "%s BIND dn=\"%s\" mech=%s sasl_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\" sasl_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 )
 {
-       int status;
        ber_tag_t tag = op->o_tag;
 
-       if(tag == LDAP_REQ_BIND) {
+       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;
-               ber_dupbv( &op->o_dn, &op->o_conn->c_dn );
-               ber_dupbv( &op->o_ndn, &op->o_conn->c_ndn );
+               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 );
        
@@ -1643,8 +1866,9 @@ static int connection_op_activate( Operation *op )
                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)
+
+       if (op->o_conn->c_conn_state == SLAP_C_INACTIVE &&
+               op->o_protocol > LDAP_VERSION2)
        {
                op->o_conn->c_conn_state = SLAP_C_ACTIVE;
        }
@@ -1653,38 +1877,41 @@ static int connection_op_activate( Operation *op )
        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 );
 
-       status = ldap_pvt_thread_pool_submit( &connection_pool,
+       rc = ldap_pvt_thread_pool_submit( &connection_pool,
                connection_operation, (void *) op );
 
-       if ( status != 0 ) {
+       if ( rc != 0 ) {
                Debug( LDAP_DEBUG_ANY,
-                       "ldap_pvt_thread_pool_submit: failed (%d) for conn=%lu\n",
-                       status, op->o_connid, 0 );
+                       "connection_op_activate: submit failed (%d) for conn=%lu\n",
+                       rc, op->o_connid, 0 );
                /* should move op to pending list */
        }
 
-       return status;
+       return rc;
 }
 
 int connection_write(ber_socket_t s)
 {
        Connection *c;
+       Operation *op;
 
        assert( connections != NULL );
 
-       ldap_pvt_thread_mutex_lock( &connections_mutex );
+       slapd_clr_write( s, 0 );
 
        c = connection_get( s );
-
-       slapd_clr_write( s, 0);
-
        if( c == NULL ) {
                Debug( LDAP_DEBUG_ANY,
                        "connection_write(%ld): no connection!\n",
                        (long)s, 0, 0 );
-               slapd_remove(s, 1, 0);
-               ldap_pvt_thread_mutex_unlock( &connections_mutex );
                return -1;
        }
 
@@ -1701,11 +1928,62 @@ int connection_write(ber_socket_t s)
        if ( ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_NEEDS_WRITE, NULL ) ) {
                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 );
-       ldap_pvt_thread_mutex_unlock( &connections_mutex );
        return 0;
 }
 
+#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,
@@ -1727,12 +2005,36 @@ connection_fake_init(
        op->o_tmpmemctx = slap_sl_mem_create(SLAP_SLAB_SIZE, SLAP_SLAB_STACK, ctx);
        op->o_tmpmfuncs = &slap_sl_mfuncs;
        op->o_threadctx = ctx;
+#ifdef LDAP_DEVEL
+       op->o_tid = ldap_pvt_thread_pool_tid( ctx );
+#endif /* LDAP_DEVEL */
 
        op->o_conn = conn;
        op->o_connid = op->o_conn->c_connid;
        connection_init_log_prefix( op );
 
-       op->o_time = slap_get_time();
+#ifdef LDAP_SLAPI
+       if ( slapi_plugins_used ) {
+               conn_fake_extblock *eb = NULL;
+
+               /* Use thread keys to make sure these eventually get cleaned up */
+               if ( ldap_pvt_thread_pool_getkey( ctx, connection_fake_init, &eb,
+                       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, connection_fake_init, eb,
+                               connection_fake_destroy );
+               } else {
+                       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
@@ -1742,4 +2044,3 @@ connection_assign_nextid( Connection *conn )
        conn->c_connid = conn_nextid++;
        ldap_pvt_thread_mutex_unlock( &conn_nextid_mutex );
 }
-