ITS#9419 Add support for HAProxy proxy protocol v2

doc/guide/admin/runningslapd.sdf

@@ -36,13 +36,23 @@ This option specifies alternative listener configurations.  The
 default is {{EX:ldap:///}} which implies {{TERM:LDAP}} over
 {{TERM:TCP}} on all interfaces on the default LDAP port 389.  You
 can specify specific host-port pairs or other protocol schemes (such
-as {{EX:ldaps://}} or {{EX:ldapi://}}).
+as {{EX:ldaps://}} or {{EX:ldapi://}}). slapd supports the HAProxy
+proxy protocol version 2, which allows a load balancer or proxy
+server to provide the remote client IP address to slapd to be used
+for access control or logging. Listeners configured using either
+{{EX:pldap:///}} or {{EX:pldaps:///}} URLS will only accept
+connections that include the necessary proxy protocol header.
+Connections to the ports used by these listeners should be restricted
+at the network level to only trusted load balancers or proxies to
+avoid spoofing of client IP addresses by third parties.
 
 !block table
-URL        Protocol        Transport
+URL        Protocol                Transport
-ldap:///   LDAP            TCP port 389
+ldap:///   LDAP                    TCP port 389
-ldaps:///  LDAP over SSL   TCP port 636
+pldap:///  proxied LDAP            TCP port 389
-ldapi:///  LDAP            IPC (Unix-domain socket)
+ldaps:///  LDAP over SSL           TCP port 636
+pldaps:/// proxied LDAP over SSL   TCP port 636
+ldapi:///  LDAP                    IPC (Unix-domain socket)
 !endblock
 
 For example, {{EX:-h

doc/man/man8/lloadd.8

@@ -142,13 +142,24 @@ For example, if lloadd is given
 it will listen on 127.0.0.1:9009 for LDAP, 0.0.0.0:636 for LDAP over TLS,
 and LDAP over IPC (Unix domain sockets).  Host 0.0.0.0 represents
 INADDR_ANY (any interface).
-A space separated list of URLs is expected.  The URLs should be of
+A space separated list of URLs is expected.  The URLs should be of the LDAP,
-the LDAP, LDAPS, or LDAPI schemes, and generally
+PLDAP, LDAPS, PLDAPS, or LDAPI schemes, and generally without a DN or other
-without a DN or other optional parameters (excepting as discussed below).
+optional parameters (excepting as discussed below).  Support for the latter
-Support for the latter two schemes depends on selected configuration
+three schemes depends on selected configuration options. Hosts may be specified
-options.  Hosts may be specified by name or IPv4 and IPv6 address formats.
+by name or IPv4 and IPv6 address formats.  Ports, if specified, must be
-Ports, if specified, must be numeric.  The default ldap:// port is \fB389\fP
+numeric.  The default ldap:// port is \fB389\fP and the default ldaps:// port
-and the default ldaps:// port is \fB636\fP.
+is \fB636\fP, same for the proxy enabled variants.
+
+The PLDAP and PLDAPS URL schemes provide support for the HAProxy proxy protocol
+version 2, which allows a load balancer or proxy server to provide the remote
+client IP address to slapd to be used for access control or logging. Ports
+configured for PLDAP or PLDAPS will only accept connections that include the
+necessary proxy protocol header. Connections to these ports should be
+restricted at the network level to only trusted load balancers or proxies to
+avoid spoofing of client IP addresses by third parties.
+
+At the moment, the load balancer does not act on the recorded address in any
+way.
 
 For LDAP over IPC,
 .B name

doc/man/man8/slapd.8

@@ -192,13 +192,21 @@ For example, if slapd is given
 it will listen on 127.0.0.1:9009 for LDAP, 0.0.0.0:636 for LDAP over TLS,
 and LDAP over IPC (Unix domain sockets).  Host 0.0.0.0 represents
 INADDR_ANY (any interface).
-A space separated list of URLs is expected.  The URLs should be of
+A space separated list of URLs is expected.  The URLs should be of the LDAP,
-the LDAP, LDAPS, or LDAPI schemes, and generally
+PLDAP, LDAPS, PLDAPS, or LDAPI schemes, and generally without a DN or other
-without a DN or other optional parameters (excepting as discussed below).
+optional parameters (excepting as discussed below).  Support for the latter
-Support for the latter two schemes depends on selected configuration 
+three schemes depends on selected configuration options. Hosts may be specified
-options.  Hosts may be specified by name or IPv4 and IPv6 address formats.
+by name or IPv4 and IPv6 address formats.  Ports, if specified, must be
-Ports, if specified, must be numeric.  The default ldap:// port is \fB389\fP
+numeric.  The default ldap:// port is \fB389\fP and the default ldaps:// port
-and the default ldaps:// port is \fB636\fP.
+is \fB636\fP, same for the proxy enabled variants.
+
+The PLDAP and PLDAPS URL schemes provide support for the HAProxy proxy protocol
+version 2, which allows a load balancer or proxy server to provide the remote
+client IP address to slapd to be used for access control or logging. Ports
+configured for PLDAP or PLDAPS will only accept connections that include the
+necessary proxy protocol header. Connections to these ports should be
+restricted at the network level to only trusted load balancers or proxies to
+avoid spoofing of client IP addresses by third parties.
 
 For LDAP over IPC,
 .B name 

include/ldap_pvt.h

@@ -32,6 +32,9 @@ ldap_pvt_url_scheme2proto LDAP_P((
 LDAP_F ( int )
 ldap_pvt_url_scheme2tls LDAP_P((
 	const char * ));
+LDAP_F ( int )
+ldap_pvt_url_scheme2proxied LDAP_P((
+	const char * ));
 
 LDAP_F ( int )
 ldap_pvt_url_scheme_port LDAP_P((

libraries/libldap/ldap-int.h

@@ -123,8 +123,12 @@ LDAP_BEGIN_DECL
 
 #define LDAP_URL_PREFIX         "ldap://"
 #define LDAP_URL_PREFIX_LEN     STRLENOF(LDAP_URL_PREFIX)
+#define PLDAP_URL_PREFIX	"pldap://"
+#define PLDAP_URL_PREFIX_LEN	STRLENOF(PLDAP_URL_PREFIX)
 #define LDAPS_URL_PREFIX	"ldaps://"
 #define LDAPS_URL_PREFIX_LEN	STRLENOF(LDAPS_URL_PREFIX)
+#define PLDAPS_URL_PREFIX	"pldaps://"
+#define PLDAPS_URL_PREFIX_LEN	STRLENOF(PLDAPS_URL_PREFIX)
 #define LDAPI_URL_PREFIX	"ldapi://"
 #define LDAPI_URL_PREFIX_LEN	STRLENOF(LDAPI_URL_PREFIX)
 #ifdef LDAP_CONNECTIONLESS

libraries/libldap/url.c

@@ -20,7 +20,7 @@
 
 /*
  *  LDAP URLs look like this:
- *    ldap[is]://host[:port][/[dn[?[attributes][?[scope][?[filter][?exts]]]]]]
+ *    [p]ldap[is]://host[:port][/[dn[?[attributes][?[scope][?[filter][?exts]]]]]]
  *
  *  where:
  *   attributes is a comma separated list
@@ -59,7 +59,7 @@ int ldap_pvt_url_scheme2proto( const char *scheme )
 		return -1;
 	}
 
-	if( strcmp("ldap", scheme) == 0 ) {
+	if( strcmp("ldap", scheme) == 0 || strcmp("pldap", scheme) == 0 ) {
 		return LDAP_PROTO_TCP;
 	}
 
@@ -67,7 +67,7 @@ int ldap_pvt_url_scheme2proto( const char *scheme )
 		return LDAP_PROTO_IPC;
 	}
 
-	if( strcmp("ldaps", scheme) == 0 ) {
+	if( strcmp("ldaps", scheme) == 0 || strcmp("pldaps", scheme) == 0 ) {
 		return LDAP_PROTO_TCP;
 	}
 #ifdef LDAP_CONNECTIONLESS
@@ -86,7 +86,7 @@ int ldap_pvt_url_scheme_port( const char *scheme, int port )
 	if( port ) return port;
 	if( scheme == NULL ) return port;
 
-	if( strcmp("ldap", scheme) == 0 ) {
+	if( strcmp("ldap", scheme) == 0 || strcmp("pldap", scheme) == 0 ) {
 		return LDAP_PORT;
 	}
 
@@ -94,7 +94,7 @@ int ldap_pvt_url_scheme_port( const char *scheme, int port )
 		return -1;
 	}
 
-	if( strcmp("ldaps", scheme) == 0 ) {
+	if( strcmp("ldaps", scheme) == 0 || strcmp("pldaps", scheme) == 0 ) {
 		return LDAPS_PORT;
 	}
 
@@ -116,7 +116,19 @@ ldap_pvt_url_scheme2tls( const char *scheme )
 		return -1;
 	}
 
-	return strcmp("ldaps", scheme) == 0;
+	return strcmp("ldaps", scheme) == 0 || strcmp("pldaps", scheme) == 0;
+}
+
+int
+ldap_pvt_url_scheme2proxied( const char *scheme )
+{
+	assert( scheme != NULL );
+
+	if( scheme == NULL ) {
+		return -1;
+	}
+
+	return strcmp("pldap", scheme) == 0 || strcmp("pldaps", scheme) == 0;
 }
 
 int
@@ -150,7 +162,7 @@ ldap_is_ldaps_url( LDAP_CONST char *url )
 		return 0;
 	}
 
-	return strcmp(scheme, "ldaps") == 0;
+	return strcmp(scheme, "ldaps") == 0 || strcmp(scheme, "pldaps");
 }
 
 int
@@ -228,6 +240,14 @@ skip_url_prefix(
 		return( p );
 	}
 
+	/* check for "pldap://" prefix */
+	if ( strncasecmp( p, PLDAP_URL_PREFIX, PLDAP_URL_PREFIX_LEN ) == 0 ) {
+		/* skip over "pldap://" prefix and return success */
+		p += PLDAP_URL_PREFIX_LEN;
+		*scheme = "pldap";
+		return( p );
+	}
+
 	/* check for "ldaps://" prefix */
 	if ( strncasecmp( p, LDAPS_URL_PREFIX, LDAPS_URL_PREFIX_LEN ) == 0 ) {
 		/* skip over "ldaps://" prefix and return success */
@@ -236,6 +256,14 @@ skip_url_prefix(
 		return( p );
 	}
 
+	/* check for "pldaps://" prefix */
+	if ( strncasecmp( p, PLDAPS_URL_PREFIX, PLDAPS_URL_PREFIX_LEN ) == 0 ) {
+		/* skip over "pldaps://" prefix and return success */
+		p += PLDAPS_URL_PREFIX_LEN;
+		*scheme = "pldaps";
+		return( p );
+	}
+
 	/* check for "ldapi://" prefix */
 	if ( strncasecmp( p, LDAPI_URL_PREFIX, LDAPI_URL_PREFIX_LEN ) == 0 ) {
 		/* skip over "ldapi://" prefix and return success */

servers/lloadd/Makefile_server.in

@@ -22,7 +22,7 @@ NT_SRCS = ../slapd/nt_svc.c
 NT_OBJS = ../slapd/nt_svc.o ../../libraries/liblutil/slapdmsg.res
 
 SRCS	+= main.c value.c \
-		  ../slapd/ch_malloc.c ../slapd/sl_malloc.c ../slapd/user.c
+		  ../slapd/ch_malloc.c ../slapd/proxyp.c ../slapd/sl_malloc.c ../slapd/user.c
 
 OBJS	= $(patsubst %.c,%.o,$(SRCS)) $(@PLAT@_OBJS)
 

servers/lloadd/daemon.c

@@ -404,6 +404,8 @@ lload_open_listener(
     l.sl_is_tls = ldap_pvt_url_scheme2tls( lud->lud_scheme );
 #endif /* HAVE_TLS */
 
+    l.sl_is_proxied = ldap_pvt_url_scheme2proxied( lud->lud_scheme );
+
 #ifdef LDAP_TCP_BUFFER
     l.sl_tcp_rmem = 0;
     l.sl_tcp_wmem = 0;
@@ -889,6 +891,16 @@ lload_listener(
     }
 #endif /* SO_KEEPALIVE || TCP_NODELAY */
 
+    if ( sl->sl_is_proxied ) {
+        if ( !proxyp( s, from ) ) {
+            Debug( LDAP_DEBUG_ANY, "lload_listener: "
+                    "proxyp(%ld) failed\n",
+                    (long)s );
+            lloadd_close( s );
+            return;
+        }
+    }
+
     cflag = 0;
     switch ( from->sa_addr.sa_family ) {
 #ifdef LDAP_PF_LOCAL
@@ -1118,8 +1130,9 @@ lload_listener_activate( void )
 
         lload_listeners[l]->sl_busy = 1;
         listener = evconnlistener_new( listener_base, lload_listener,
-                lload_listeners[l], LEV_OPT_THREADSAFE, SLAPD_LISTEN_BACKLOG,
+                lload_listeners[l],
-                lload_listeners[l]->sl_sd );
+                LEV_OPT_THREADSAFE|LEV_OPT_DEFERRED_ACCEPT,
+                SLAPD_LISTEN_BACKLOG, lload_listeners[l]->sl_sd );
         if ( !listener ) {
             int err = sock_errno();
 

servers/lloadd/lload.h

@@ -469,6 +469,7 @@ struct LloadListener {
 #ifdef HAVE_TLS
     int sl_is_tls;
 #endif
+    int sl_is_proxied;
     struct event_base *base;
     struct evconnlistener *listener;
     int sl_mute; /* Listener is temporarily disabled due to emfile */

servers/slapd/Makefile.in

@@ -29,7 +29,7 @@ SRCS	= main.c globals.c bconfig.c config.c daemon.c \
 		dn.c compare.c modify.c delete.c modrdn.c ch_malloc.c \
 		value.c ava.c bind.c unbind.c abandon.c filterentry.c \
 		phonetic.c acl.c str2filter.c aclparse.c init.c user.c \
-		lock.c controls.c extended.c passwd.c \
+		lock.c controls.c extended.c passwd.c proxyp.c \
 		schema.c schema_check.c schema_init.c schema_prep.c \
 		schemaparse.c ad.c at.c mr.c syntax.c oc.c saslauthz.c \
 		oidm.c starttls.c index.c sets.c referral.c root_dse.c \
@@ -47,7 +47,7 @@ OBJS	= main.o globals.o bconfig.o config.o daemon.o \
 		dn.o compare.o modify.o delete.o modrdn.o ch_malloc.o \
 		value.o ava.o bind.o unbind.o abandon.o filterentry.o \
 		phonetic.o acl.o str2filter.o aclparse.o init.o user.o \
-		lock.o controls.o extended.o passwd.o \
+		lock.o controls.o extended.o passwd.o proxyp.o \
 		schema.o schema_check.o schema_init.o schema_prep.o \
 		schemaparse.o ad.o at.o mr.o syntax.o oc.o saslauthz.o \
 		oidm.o starttls.o index.o sets.o referral.o root_dse.o \

servers/slapd/daemon.c

@@ -1549,6 +1549,8 @@ slap_open_listener(
 	}
 #endif /* HAVE_TLS */
 
+	l.sl_is_proxied = ldap_pvt_url_scheme2proxied( lud->lud_scheme );
+
 #ifdef LDAP_TCP_BUFFER
 	l.sl_tcp_rmem = 0;
 	l.sl_tcp_wmem = 0;
@@ -2270,6 +2272,13 @@ slap_listener(
 	case AF_INET6:
 #  endif /* LDAP_PF_INET6 */
 	case AF_INET:
+		if ( sl->sl_is_proxied ) {
+			if ( !proxyp( sfd, &from ) ) {
+				Debug( LDAP_DEBUG_ANY, "slapd(%ld): proxyp failed\n", (long)sfd );
+				slapd_close( sfd );
+				return 0;
+			}
+		}
 		lutil_sockaddrstr( &from, &peerbv );
 		break;
 

servers/slapd/proto-slap.h

@@ -1556,6 +1556,11 @@ LDAP_SLAPD_F (void) slap_passwd_init (void);
  */
 LDAP_SLAPD_F (char *) phonetic LDAP_P(( char *s ));
 
+/*
+ * proxyp.c
+ */
+LDAP_SLAPD_F (int) proxyp LDAP_P((ber_socket_t sfd, Sockaddr *from));
+
 /*
  * referral.c
  */

servers/slapd/proxyp.c

@@ -0,0 +1,219 @@
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2000-2020 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>.
+ */
+
+#include "portable.h"
+#include "slap.h"
+
+#ifdef HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#ifdef HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+
+#include <lber_types.h>
+#include <ac/string.h>
+#include <ac/errno.h>
+
+typedef struct {
+	uint8_t  sig[12];	/* hex 0d 0a 0d 0a 00 0d 0a 51 55 49 54 0a */
+	uint8_t  ver_cmd;	/* protocol version and command */
+	uint8_t  fam;		/* protocol family and address */
+	uint16_t len;		/* length of address data */
+} proxyp_header;
+
+typedef union {
+	struct {	/* for TCP/UDP over IPv4, len = 12 */
+		uint32_t src_addr;
+		uint32_t dst_addr;
+		uint16_t src_port;
+		uint16_t dst_port;
+	} ip4;
+	struct {	/* for TCP/UDP over IPv6, len = 36 */
+		uint8_t  src_addr[16];
+		uint8_t  dst_addr[16];
+		uint16_t src_port;
+		uint16_t dst_port;
+	} ip6;
+	struct {	/* for AF_UNIX sockets, len = 216 */
+		uint8_t src_addr[108];
+		uint8_t dst_addr[108];
+	} unx;
+} proxyp_addr;
+
+static const uint8_t proxyp_sig[12] = {
+	0x0d, 0x0a, 0x0d, 0x0a, 0x00, 0x0d, 0x0a, 0x51, 0x55, 0x49, 0x54, 0x0a,
+};
+
+int
+proxyp( ber_socket_t sfd, Sockaddr *from ) {
+	proxyp_header pph;
+	proxyp_addr ppa;
+	char peername[LUTIL_ADDRLEN];
+	struct berval peerbv = BER_BVC(peername);
+	/* Maximum size of header minus static component size is max option size */
+	uint8_t proxyp_options[536 - 16];
+	int pph_len;
+	int ret;
+
+	peername[0] = '\0';
+
+	do {
+		ret = tcp_read( SLAP_FD2SOCK( sfd ), &pph, sizeof(pph) );
+	} while ( ret == -1 && errno == EINTR );
+
+	if ( ret == -1 ) {
+		char ebuf[128];
+		int save_errno = errno;
+		Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+				"header read failed %d (%s)\n",
+				(long)sfd, save_errno,
+				AC_STRERROR_R( save_errno, ebuf, sizeof(ebuf) ) );
+		return 0;
+	} else if ( ret != sizeof(pph) ) {
+		Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+				"header read insufficient data %d\n",
+				(long)sfd, ret );
+		return 0;
+	}
+
+	if ( memcmp( pph.sig, proxyp_sig, 12 ) != 0 ) {
+		Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+				"invalid header signature\n", (long)sfd );
+		return 0;
+	}
+
+	if ( ( pph.ver_cmd & 0xF0 ) != 0x20 ) {
+		Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+				"invalid header version %x\n",
+				(long)sfd, pph.ver_cmd & 0xF0 );
+		return 0;
+	}
+
+	pph_len = ntohs( pph.len );
+	if ( ( pph.ver_cmd & 0x0F ) == 0x01 ) { /* PROXY command */
+		int addr_len;
+		switch ( pph.fam ) {
+		case 0x11: /* TCPv4 */
+			addr_len = sizeof( ppa.ip4 );
+			break;
+		case 0x21: /* TCPv6 */
+			addr_len = sizeof( ppa.ip6 );
+			break;
+		default:
+			Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+					"unsupported protocol %x\n",
+					(long)sfd, pph.fam );
+			return 0;
+		}
+
+		if ( pph_len < addr_len ) {
+			Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+					"address length %d too small, expecting %d\n",
+					(long)sfd, pph_len, addr_len );
+			return 0;
+		}
+
+		do {
+			ret = tcp_read( SLAP_FD2SOCK (sfd), &ppa, addr_len );
+		} while ( ret == -1 && errno == EINTR );
+
+		if ( ret == -1 ) {
+			char ebuf[128];
+			int save_errno = errno;
+			Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+					"address read failed %d (%s)\n",
+					(long)sfd, save_errno,
+					AC_STRERROR_R( save_errno, ebuf, sizeof(ebuf) ) );
+			return 0;
+		} else if ( ret != addr_len ) {
+			Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+					"address read insufficient data, expecting %d, read %d\n",
+					(long)sfd, addr_len, ret );
+			return 0;
+		}
+
+		pph_len -= addr_len;
+	}
+
+	switch ( pph.ver_cmd & 0x0F ) {
+	case 0x01: /* PROXY command */
+		switch ( pph.fam ) {
+		case 0x11: /* TCPv4 */
+			lutil_sockaddrstr( from, &peerbv );
+			Debug( LDAP_DEBUG_STATS, "proxyp(%ld): via %s\n",
+					(long)sfd, peername );
+
+			from->sa_in_addr.sin_family = AF_INET;
+			from->sa_in_addr.sin_addr.s_addr = ppa.ip4.src_addr;
+			from->sa_in_addr.sin_port = ppa.ip4.src_port;
+			break;
+
+		case 0x21: /* TCPv6 */
+			lutil_sockaddrstr( from, &peerbv );
+			Debug( LDAP_DEBUG_STATS, "proxyp(%ld): via %s\n",
+					(long)sfd, peername );
+			from->sa_in6_addr.sin6_family = AF_INET6;
+			memcpy( &from->sa_in6_addr.sin6_addr, ppa.ip6.src_addr,
+					sizeof(ppa.ip6.src_addr) );
+			from->sa_in6_addr.sin6_port = ppa.ip6.src_port;
+			break;
+		}
+
+		break;
+
+	case 0x00: /* LOCAL command */
+		Debug( LDAP_DEBUG_CONNS, "proxyp(%ld): "
+				"local connection, ignoring proxy data\n",
+				(long)sfd );
+		break;
+
+	default:
+		Debug( LDAP_DEBUG_ANY, "proxyp(%ld): invalid command %x\n",
+				(long)sfd, pph.ver_cmd & 0x0F );
+		return 0;
+	}
+
+	/* Clear out any options left in proxy packet */
+	if ( pph_len > 0 ) {
+		if (pph_len > sizeof( proxyp_options ) ) {
+			Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+					"options size %d too big\n",
+					(long)sfd, pph_len );
+			return 0;
+		}
+
+		do {
+			ret = tcp_read( SLAP_FD2SOCK (sfd), &proxyp_options, pph_len );
+		} while ( ret == -1 && errno == EINTR );
+
+		if ( ret == -1 ) {
+			char ebuf[128];
+			int save_errno = errno;
+			Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+					"options read failed %d (%s)\n",
+					(long)sfd, save_errno,
+					AC_STRERROR_R( save_errno, ebuf, sizeof(ebuf) ) );
+			return 0;
+		} else if ( ret != pph_len ) {
+			Debug( LDAP_DEBUG_ANY, "proxyp(%ld): "
+					"options read insufficient data, expecting %d, read %d\n",
+					(long)sfd, pph_len, ret );
+			return 0;
+		}
+	}
+
+	return 1;
+}

servers/slapd/slap.h

@@ -3003,6 +3003,7 @@ struct Listener {
 #ifdef LDAP_CONNECTIONLESS
 	int	sl_is_udp;		/* UDP listener is also data port */
 #endif
+	int	sl_is_proxied;
 	int	sl_mute;	/* Listener is temporarily disabled due to emfile */
 	int	sl_busy;	/* Listener is busy (accept thread activated) */
 	ber_socket_t sl_sd;