LDAP_BIND(3)              Library Functions Manual              LDAP_BIND(3)

NAME         top

       ldap_bind,    ldap_bind_s,    ldap_simple_bind,   ldap_simple_bind_s,
       ldap_sasl_bind,    ldap_sasl_bind_s,    ldap_sasl_interactive_bind_s,
       ldap_parse_sasl_bind_result,        ldap_unbind,       ldap_unbind_s,
       ldap_unbind_ext, ldap_unbind_ext_s, ldap_set_rebind_proc - LDAP  bind

LIBRARY         top

       OpenLDAP LDAP (libldap, -lldap)

SYNOPSIS         top

       #include <ldap.h>

       int ldap_bind(LDAP *ld, const char *who, const char *cred,
              int method);

       int ldap_bind_s(LDAP *ld, const char *who, const char *cred,
              int method);

       int ldap_simple_bind(LDAP *ld, const char *who, const char *passwd);

       int ldap_simple_bind_s(LDAP *ld, const char *who, const char *passwd);

       int ldap_sasl_bind(LDAP *ld, const char *dn, const char *mechanism,
              struct berval *cred, LDAPControl *sctrls[],
              LDAPControl *cctrls[], int *msgidp);

       int ldap_sasl_bind_s(LDAP *ld, const char *dn, const char *mechanism,
              struct berval *cred, LDAPControl *sctrls[],
              LDAPControl *cctrls[], struct berval **servercredp);

       int ldap_parse_sasl_bind_result(LDAP *ld, LDAPMessage *res,
              struct berval **servercredp, int freeit);

       int ldap_sasl_interactive_bind_s(LDAP *ld, const char *dn,
              const char *mechs,
              LDAPControl *sctrls[], LDAPControl *cctrls[],
              unsigned flags, LDAP_SASL_INTERACT_PROC *interact,
              void *defaults);

       int ldap_sasl_interactive_bind(LDAP *ld, const char *dn,
              const char *mechs,
              LDAPControl *sctrls[], LDAPControl *cctrls[],
              unsigned flags, LDAP_SASL_INTERACT_PROC *interact,
              void *defaults, LDAPMessage *result,
              const char **rmechp, int *msgidp);

       int (LDAP_SASL_INTERACT_PROC)(LDAP *ld, unsigned flags, void *defaults, void *sasl_interact);

       int ldap_unbind(LDAP *ld);

       int ldap_unbind_s(LDAP *ld);

       int ldap_unbind_ext(LDAP *ld, LDAPControl *sctrls[],
              LDAPControl *cctrls[]);

       int ldap_unbind_ext_s(LDAP *ld, LDAPControl *sctrls[],
              LDAPControl *cctrls[]);

       int ldap_set_rebind_proc (LDAP *ld, LDAP_REBIND_PROC *ldap_proc, void *params);

       int (LDAP_REBIND_PROC)(LDAP *ld, LDAP_CONST char *url, ber_tag_t request, ber_int_t msgid, void *params);

DESCRIPTION         top

       These routines provide various interfaces to the LDAP bind operation.
       After an association with an LDAP server is made using ldap_init(3),
       an LDAP bind operation should be performed before other operations
       are attempted over the connection.  An LDAP bind is required when
       using Version 2 of the LDAP protocol; it is optional for Version 3
       but is usually needed due to security considerations.

       There are three types of bind calls, ones providing simple
       authentication, ones providing SASL authentication, and general
       routines capable of doing either simple or SASL authentication.

       SASL (Simple Authentication and Security Layer) can negotiate one of
       many different kinds of authentication.  Both synchronous and
       asynchronous versions of each variant of the bind call are provided.
       All routines take ld as their first parameter, as returned from


       The simplest form of the bind call is ldap_simple_bind_s().  It takes
       the DN to bind as in who, and the userPassword associated with the
       entry in passwd.  It returns an LDAP error indication (see
       ldap_error(3)).  The ldap_simple_bind() call is asynchronous, taking
       the same parameters but only initiating the bind operation and
       returning the message id of the request it sent.  The result of the
       operation can be obtained by a subsequent call to ldap_result(3).


       The ldap_bind() and ldap_bind_s() routines can be used when the
       authentication method to use needs to be selected at runtime.  They
       both take an extra method parameter selecting the authentication
       method to use.  It should be set to LDAP_AUTH_SIMPLE to select simple
       authentication.  ldap_bind() returns the message id of the request it
       initiates.  ldap_bind_s() returns an LDAP error indication.


       For SASL binds the server always ignores any provided DN, so the dn
       parameter should always be NULL.  ldap_sasl_bind_s() sends a single
       SASL bind request with the given SASL mechanism and credentials in
       the cred parameter. The format of the credentials depends on the
       particular SASL mechanism in use. For mechanisms that provide mutual
       authentication the server's credentials will be returned in the
       servercredp parameter.  The routine returns an LDAP error indication
       (see ldap_error(3)).  The ldap_sasl_bind() call is asynchronous,
       taking the same parameters but only sending the request and returning
       the message id of the request it sent. The result of the operation
       can be obtained by a subsequent call to ldap_result(3).  The result
       must be additionally parsed by ldap_parse_sasl_bind_result() to
       obtain any server credentials sent from the server.

       Many SASL mechanisms require multiple message exchanges to perform a
       complete authentication. Applications should generally use
       ldap_sasl_interactive_bind_s() rather than calling the basic
       ldap_sasl_bind() functions directly. The mechs parameter should
       contain a space-separated list of candidate mechanisms to use. If
       this parameter is NULL or empty the library will query the
       supportedSASLMechanisms attribute from the server's rootDSE for the
       list of SASL mechanisms the server supports. The flags parameter
       controls the interaction used to retrieve any necessary SASL
       authentication parameters and should be one of:

              use defaults if available, prompt otherwise

              always prompt

              never prompt

       The interact function uses the provided defaults to handle requests
       from the SASL library for particular authentication parameters. There
       is no defined format for the defaults information; it is up to the
       caller to use whatever format is appropriate for the supplied
       interact function.  The sasl_interact parameter comes from the
       underlying SASL library. When used with Cyrus SASL this is an array
       of sasl_interact_t structures. The Cyrus SASL library will prompt for
       a variety of inputs, including:

              the realm for the authentication attempt

              the username to authenticate

              the password for the provided username

              the username to use for proxy authorization

              generic prompt for input with input echoing disabled

              generic prompt for input with input echoing enabled

              indicates the end of the array of prompts

       See the Cyrus SASL documentation for more details.

       Applications which need to manage connections asynchronously may use
       ldap_sasl_interactive_bind() instead of the synchronous version.  A
       valid mechs parameter must be supplied, otherwise the library will be
       forced to query the server for a list of supported mechanisms, and
       this query will be performed synchronously.  The other parameters are
       the same as for the synchronous function, with three additional
       parameters.  The actual SASL mechanism that was used, and the message
       ID for use with ldap_result() will be returned in rmechp and msgidp,
       respectively.  The value in rmechp must not be modified by the caller
       and must be passed back on each subsequent call. The message obtained
       from ldap_result() must be passed in the result parameter.  This
       parameter must be NULL when initiating a new Bind. The caller must
       free the result message after each call using ldap_msgfree().  The
       ldap_sasl_interactive_bind() function returns an LDAP result code. If
       the code is LDAP_SASL_BIND_IN_PROGRESS then the Bind is not complete
       yet, and this function must be called again with the next result from
       the server.

REBINDING         top

       The ldap_set_rebind_proc function() sets the process to use for
       binding when an operation returns a referral. This function is used
       when an application needs to bind to another server in order to
       follow a referral or search continuation reference.

       The function takes ld, the rebind function, and the params, the
       arbitrary data like state information which the client might need to
       properly rebind.  The LDAP_OPT_REFERRALS option in the ld must be set
       to ON for the libraries to use the rebind function. Use the
       ldap_set_option function to set the value.

       The rebind function parameters are as follows:

       The ld parameter must be used by the application when binding to the
       referred server if the application wants the libraries to follow the

       The url parameter points to the URL referral string received from the
       LDAP server.  The LDAP application can use the ldap_url_parse(3)
       function to parse the string into its components.

       The request parameter specifies the type of request that generated
       the referral.

       The msgid parameter specifies the message ID of the request
       generating the referral.

       The params parameter is the same value as passed originally to the
       ldap_set_rebind_proc() function.

       The LDAP libraries set all the parameters when they call the rebind
       function. The application should not attempt to free either the ld or
       the url structures in the rebind function.

       The application must supply to the rebind function the required
       authentication information such as, user name, password, and
       certificates. The rebind function must use a synchronous bind method.

UNBINDING         top

       The ldap_unbind() call is used to unbind from the directory,
       terminate the current association, and free the resources contained
       in the ld structure.  Once it is called, the connection to the LDAP
       server is closed, and the ld structure is invalid.  The
       ldap_unbind_s() call is just another name for ldap_unbind(); both of
       these calls are synchronous in nature.

       The ldap_unbind_ext() and ldap_unbind_ext_s() allows the operations
       to specify  controls.

ERRORS         top

       Asynchronous routines will return -1 in case of error, setting the
       ld_errno parameter of the ld structure.  Synchronous routines return
       whatever ld_errno is set to.  See ldap_error(3) for more information.

NOTES         top

       If an anonymous bind is sufficient for the application, the rebind
       process need not be provided. The LDAP libraries with the
       LDAP_OPT_REFERRALS option set to ON (default value) will
       automatically follow referrals using an anonymous bind.

       If the application needs stronger authentication than an anonymous
       bind, you need to provide a rebind process for that authentication
       method.  The bind method must be synchronous.

SEE ALSO         top

       ldap(3), ldap_error(3), ldap_open(3), ldap_set_option(3),
       ldap_url_parse(3) RFC 4422 (, Cyrus SASL


       OpenLDAP Software is developed and maintained by The OpenLDAP Project
       <>.  OpenLDAP Software is derived from the
       University of Michigan LDAP 3.3 Release.

COLOPHON         top

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OpenLDAP LDVERSION               RELEASEDATE                    LDAP_BIND(3)