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connection.c

/* $OpenLDAP: pkg/ldap/servers/slapd/connection.c,v 1.358.2.16 2008/04/21 18:51:10 quanah Exp $ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
 *
 * Copyright 1998-2008 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 "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_SLAPI
#include "slapi/slapi.h"
#endif

/* protected by connections_mutex */
static ldap_pvt_thread_mutex_t connections_mutex;
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) */
#define SLAP_C_INACTIVE             0x01  /* zero threads */
#define SLAP_C_ACTIVE               0x02  /* one or more threads */
#define SLAP_C_BINDING              0x03  /* binding */
#define SLAP_C_CLOSING              0x04  /* closing */
#define SLAP_C_CLIENT               0x05  /* outbound client conn */

const char *
connection_state2str( int state )
{
      switch( state ) {
      case SLAP_C_INVALID:    return "!";
      case SLAP_C_INACTIVE:   return "|";
      case SLAP_C_ACTIVE:           return "";
      case SLAP_C_BINDING:    return "B";
      case SLAP_C_CLOSING:    return "C";
      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",
                  0, 0, 0 );
            return -1;
      }

      /* should check return of every call */
      ldap_pvt_thread_mutex_init( &connections_mutex );
      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), 0 );
            return -1;
      }

      assert( connections[0].c_struct_state == SLAP_C_UNINITIALIZED );
      assert( connections[dtblsize-1].c_struct_state == SLAP_C_UNINITIALIZED );

      for (i=0; i<dtblsize; i++) connections[i].c_conn_idx = i;

      /*
       * 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",
                  0, 0, 0 );
            return -1;
      }

      for ( i = 0; i < dtblsize; i++ ) {
            if( connections[i].c_struct_state != SLAP_C_UNINITIALIZED ) {
                  ber_sockbuf_free( connections[i].c_sb );
                  ldap_pvt_thread_mutex_destroy( &connections[i].c_mutex );
                  ldap_pvt_thread_mutex_destroy( &connections[i].c_write_mutex );
                  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] );
                  }
#endif
            }
      }

      free( connections );
      connections = NULL;

      ldap_pvt_thread_mutex_destroy( &connections_mutex );
      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++ ) {
            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 );
            }
      }

      return 0;
}

/*
 * Timeout idle connections.
 */
int connections_timeout_idle(time_t now)
{
      int i = 0;
      int 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_conn_state == SLAP_C_CLIENT ) {
                  continue;
            }

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

      return i;
}

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

      Debug( LDAP_DEBUG_ARGS,
            "connection_get(%ld)\n",
            (long) s, 0, 0 );

      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 );

            assert( c->c_struct_state != SLAP_C_UNINITIALIZED );

            if( c->c_struct_state != SLAP_C_USED ) {
                  /* connection must have been closed due to resched */

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

                  Debug( LDAP_DEBUG_TRACE,
                        "connection_get(%d): connection not used\n",
                        s, 0, 0 );

                  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, 0 );

            c->c_n_get++;

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

#ifndef SLAPD_MONITOR
            if ( global_idletimeout > 0 )
#endif /* ! SLAPD_MONITOR */
            {
                  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;
      int doinit = 0;
      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, 0, 0 );
            return NULL;
      }

      assert( s >= 0 );
      assert( s < dtblsize );
      c = &connections[s];
      if( c->c_struct_state == SLAP_C_UNINITIALIZED ) {
            doinit = 1;
      } else {
            assert( c->c_struct_state == SLAP_C_UNUSED );
      }

      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;
            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);

#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;
            c->c_sasl_sockctx = NULL;
            c->c_sasl_extra = NULL;
            c->c_sasl_bindop = 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;

            /* should check status of thread calls */
            ldap_pvt_thread_mutex_init( &c->c_mutex );
            ldap_pvt_thread_mutex_init( &c->c_write_mutex );
            ldap_pvt_thread_cond_init( &c->c_write_cv );

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

      ldap_pvt_thread_mutex_lock( &c->c_mutex );

      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) );
#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 );
      assert( c->c_sasl_sockctx == NULL );
      assert( c->c_sasl_extra == NULL );
      assert( c->c_sasl_bindop == NULL );
      assert( c->c_currentber == NULL );
      assert( c->c_writewaiter == 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_struct_state = SLAP_C_USED;
            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;

#ifndef SLAPD_MONITOR
      if ( global_idletimeout > 0 )
#endif /* ! SLAPD_MONITOR */
      {
            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, 0 );
      }

      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_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;

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

      backend_connection_init(c);

      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_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);

      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_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 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 );
            }
      }
}

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

      int state;
      assert( c != NULL );
      assert( c->c_struct_state == SLAP_C_USED );

      state = c->c_conn_state;

      assert( state != SLAP_C_INVALID );

      return state == SLAP_C_CLOSING;
}

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

      Operation *o, *next, op = {0};
      Opheader ohdr = {0};
      SlapReply rs = {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 ) {
            next = LDAP_STAILQ_NEXT( o, o_next );
            op.orn_msgid = o->o_msgid;
            o->o_abandon = 1;
            op.o_bd = frontendDB;
            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, NULL );
      }

      /* 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 );
            LDAP_STAILQ_NEXT(o, o_next) = NULL;
            slap_op_free( o, NULL );
      }
}

void connection_closing( Connection *c, const char *why )
{
      assert( connections != NULL );
      assert( c != NULL );
      assert( c->c_struct_state == SLAP_C_USED );
      assert( c->c_conn_state != SLAP_C_INVALID );

      /* c_mutex must be locked by caller */

      if( c->c_conn_state != SLAP_C_CLOSING ) {
            Debug( LDAP_DEBUG_TRACE,
                  "connection_closing: readying conn=%lu sd=%d for close\n",
                  c->c_connid, c->c_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( c->c_sd, 0 );

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

            /* wake write blocked operations */
            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( c->c_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( c->c_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 )
{
      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: c_mutex should be locked by caller */

      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, c->c_sd, 0 );
            return;
      }

      Debug( LDAP_DEBUG_TRACE, "connection_close: conn=%lu sd=%d\n",
            c->c_connid, c->c_sd, 0 );

      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;
}

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

      ldap_pvt_thread_mutex_lock( &connections_mutex );
      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);
}

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;

      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 );
                  continue;
            }

            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;
            }

            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 );
      }

      ldap_pvt_thread_mutex_unlock( &connections_mutex );
      return c;
}

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.
 */

#ifdef SLAPD_MONITOR
/* 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)
#else /* !SLAPD_MONITOR */
#define INCR_OP_INITIATED(index) do { } 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_thread_mutex_unlock( &op->o_counters->sc_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_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 );
#ifdef SLAPD_MONITOR
                  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 ] );
                  }
#endif /* SLAPD_MONITOR */
                  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;
}

static void *
connection_operation( void *ctx, void *arg_v )
{
      int rc = LDAP_OTHER;
      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;

      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, 0 );
            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, 0, 0 );
            send_ldap_error( op, &rs, LDAP_OPERATIONS_ERROR,
                  "SASL bind in progress" );
            rc = LDAP_OPERATIONS_ERROR;
            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.
       */
#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 ( opidx != SLAP_OP_LAST ) {
            /* increment completed operations count 
             * only if operation was initiated
             * and rc != SLAPD_DISCONNECT */
            INCR_OP_COMPLETED( opidx );
      }

      if ( op->o_cancel == SLAP_CANCEL_REQ ) {
            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 )
      {
            ldap_pvt_thread_yield();
      }

      ldap_pvt_thread_mutex_lock( &conn->c_mutex );

      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++;

      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 );
      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 );
            slapd_set_read( sfd, 1 );
      }
      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_conn_state = SLAP_C_INVALID;
      c->c_struct_state = SLAP_C_UNUSED;
      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 );
      }
      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, 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;
}

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, 0, 0 );

            return -1;
      }

      c->c_n_read++;

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

#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;

                  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 );
                  }
                  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( !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", 0, 0, 0 );
            return -1;
      }

      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;

            sprintf( peername, "IP=%s:%d",
                  inet_ntoa( peeraddr.sa_in_addr.sin_addr ),
                  (unsigned) ntohs( peeraddr.sa_in_addr.sin_port ) );
            Statslog( LDAP_DEBUG_STATS,
                  "conn=%lu UDP request from %s (%s) accepted.\n",
                  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 = sock_errno();

            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",
                  conn->c_sd, err, sock_errstr(err) );
                  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, 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 );
            ber_free( ber, 1 );

            return -1;
      }

#ifdef LDAP_CONNECTIONLESS
      if( conn->c_is_udp ) {
            if( tag == LBER_OCTETSTRING ) {
                  ber_get_stringa( ber, &cdn );
                  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, 0, 0 );
                  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 );

      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", 0, 0, 0 );
                  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", 0, 0, 0 );
                        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, 0 );
            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 );
            }
      }

#ifdef NO_THREADS
      if ( conn->c_struct_state != SLAP_C_USED ) {
            /* connection must have got closed underneath us */
            return 1;
      }
#endif

      assert( conn->c_struct_state == SLAP_C_USED );
      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_TRACE, "connection_resched: "
                  "attempting closing conn=%lu sd=%d\n",
                  conn->c_connid, conn->c_sd, 0 );
            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 );
      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 )
{
      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, 0 );
            /* should move op to pending list */
      }

      return rc;
}

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

      assert( connections != NULL );

      slapd_clr_write( s, 0 );

      c = connection_get( s );
      if( c == NULL ) {
            Debug( LDAP_DEBUG_ANY,
                  "connection_write(%ld): no connection!\n",
                  (long)s, 0, 0 );
            return -1;
      }

      c->c_n_write++;

      Debug( LDAP_DEBUG_TRACE,
            "connection_write(%d): waking output for id=%lu\n",
            s, c->c_connid, 0 );
      ldap_pvt_thread_cond_signal( &c->c_write_cv );

      if ( ber_sockbuf_ctrl( c->c_sb, LBER_SB_OPT_NEEDS_READ, NULL ) ) {
            slapd_set_read( s, 1 );
      }
      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 );
      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,
      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_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 );
}

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