LDAP_BIND(3)

NAME
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 routines

LIBRARY
OpenLDAP LDAP (libldap, -lldap)

SYNOPSIS
#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_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);"

DESCRIPTION

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) that 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 ldap_init(3).

SIMPLE AUTHENTICATION
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).

GENERAL AUTHENTICATION
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.

SASL AUTHENTICATION
Description still under construction...

REBINDING

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 has the following syntax. int rebind_function (LDAP *ld, const char *url,int request,ber_int_t msgid);

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

The url parameter points to the URL referral string received from the LDAP server. The LDAP application can use the ldap_url_parse()

The request parameter specifies the request operation that generated the referral. function to parse the string into its components.

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

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
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 sepicify controls.

ERRORS
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
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
ldap(3), ldap_error(3), ldap_open(3), ldap_set_option(3), ldap_url_parse(3) RFC 4422 (http://www.rfc-editor.org), Cyrus SASL (http://asg.web.cmu.edu/sasl/)

ACKNOWLEDGEMENTS
OpenLDAP is developed and maintained by The OpenLDAP Project (http://www.openldap.org/). OpenLDAP is derived from University of Michigan LDAP 3.3 Release.