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LDAP_GET_OPTION(3) Library Functions Manual LDAP_GET_OPTION(3)

NAME

ldap_get_option, ldap_set_option - LDAP option handling routines

LIBRARY

OpenLDAP LDAP (libldap, -lldap)

SYNOPSIS

#include <ldap.h>
int ldap_get_option(LDAP *ld, int option, void *outvalue);
int ldap_set_option(LDAP *ld, int option, const void *invalue);

DESCRIPTION

These routines provide access to options stored either in a LDAP handle or as global options, where applicable. They make use of a neutral interface, where the type of the value either retrieved by ldap_get_option(3) or set by ldap_set_option(3) is cast to void *. The actual type is determined based on the value of the option argument. Global options are set/retrieved by passing a NULL LDAP handle. LDAP handles inherit their default settings from the global options in effect at the time the handle is created.

Fills-in a LDAPAPIFeatureInfo; outvalue must be a LDAPAPIFeatureInfo *, pointing to an already allocated struct. The ldapaif_info_version field of the struct must be initialized to LDAP_FEATURE_INFO_VERSION before making the call. The ldapaif_name field must be set to the name of a feature to query. This is a read-only option.
Fills-in a LDAPAPIInfo; outvalue must be a LDAPAPIInfo *, pointing to an already allocated struct. The ldapai_info_version field of the struct must be initialized to LDAP_API_INFO_VERSION before making the call. If the version passed in does not match the current library version, the expected version number will be stored in the struct and the call will fail. The caller is responsible for freeing the elements of the ldapai_extensions array and the array itself using ldap_memfree(3). The caller must also free the ldapi_vendor_name. This is a read-only option.
Sets/gets the client-side controls to be used for all operations. This is now deprecated as modern LDAP C API provides replacements for all main operations which accepts client-side controls as explicit arguments; see for example ldap_search_ext(3), ldap_add_ext(3), ldap_modify_ext(3) and so on. outvalue must be LDAPControl ***, and the caller is responsible of freeing the returned controls, if any, by calling ldap_controls_free(3), while invalue must be LDAPControl *const *; the library duplicates the controls passed via invalue.
Sets/gets the status of the asynchronous connect flag. invalue should either be LDAP_OPT_OFF or LDAP_OPT_ON; outvalue must be int *. When set, the library will call connect(2) and return, without waiting for response. This leaves the handle in a connecting state. Subsequent calls to library routines will poll for completion of the connect before performing further operations. As a consequence, library calls that need to establish a connection with a DSA do not block even for the network timeout (option LDAP_OPT_NETWORK_TIMEOUT). This option is OpenLDAP specific.
This option allows to set a connect callback. invalue must be a const struct ldap_conncb *. Callbacks are executed in last in-first served order. Handle-specific callbacks are executed first, followed by global ones. Right before freeing the callback structure, the lc_del callback handler is passed a NULL Sockbuf. Calling ldap_get_option(3) for this option removes the callback whose pointer matches outvalue. This option is OpenLDAP specific.
Sets/gets the debug level of the client library. invalue must be a const int *; outvalue must be a int *. Valid debug levels are LDAP_DEBUG_ANY, LDAP_DEBUG_ARGS, LDAP_DEBUG_BER, LDAP_DEBUG_CONNS, LDAP_DEBUG_NONE, LDAP_DEBUG_PACKETS, LDAP_DEBUG_PARSE, and LDAP_DEBUG_TRACE. This option is OpenLDAP specific.
Sets/gets a string containing the DN to be used as default base for search operations. outvalue must be a char **, and the caller is responsible of freeing the returned string by calling ldap_memfree(3), while invalue must be a const char *; the library duplicates the corresponding string. This option is OpenLDAP specific.
Sets/gets the value that defines when alias dereferencing must occur. invalue must be const int *; outvalue must be int *. They cannot be NULL. The value of *invalue should be one of LDAP_DEREF_NEVER (the default), LDAP_DEREF_SEARCHING, LDAP_DEREF_FINDING, or LDAP_DEREF_ALWAYS. Note that this has ever been the only means to determine alias dereferencing within search operations.
Returns the file descriptor associated to the socket buffer of the LDAP handle passed in as ld; outvalue must be a int *. This is a read-only, handle-specific option.
Sets/gets a string containing the error string associated to the LDAP handle. This option was formerly known as LDAP_OPT_ERROR_STRING. outvalue must be a char **, and the caller is responsible of freeing the returned string by calling ldap_memfree(3), while invalue must be a char *; the library duplicates the corresponding string.
Sets/gets a space-separated list of hosts to be contacted by the library when trying to establish a connection. This is now deprecated in favor of LDAP_OPT_URI. outvalue must be a char **, and the caller is responsible of freeing the resulting string by calling ldap_memfree(3), while invalue must be a const char *; the library duplicates the corresponding string.
Sets/gets a string containing the matched DN associated to the LDAP handle. outvalue must be a char **, and the caller is responsible of freeing the returned string by calling ldap_memfree(3), while invalue must be a const char *; the library duplicates the corresponding string.
Sets/gets the network timeout value after which poll(2)/select(2) following a connect(2) returns in case of no activity. outvalue must be a struct timeval ** (the caller has to free *outvalue using ldap_memfree(3)), and invalue must be a const struct timeval *. They cannot be NULL. Using a struct with seconds set to -1 results in an infinite timeout, which is the default. This option is OpenLDAP specific.
Sets/gets the protocol version. outvalue and invalue must be int *.
Sets/gets an array containing the referral URIs associated to the LDAP handle. outvalue must be a char ***, and the caller is responsible of freeing the returned string by calling ldap_memvfree(3), while invalue must be a NULL-terminated char *const *; the library duplicates the corresponding string. This option is OpenLDAP specific.
Determines whether the library should implicitly chase referrals or not. invalue must be const int *; its value should either be LDAP_OPT_OFF or LDAP_OPT_ON. outvalue must be int *.
Determines whether the library should implicitly restart connections (FIXME). invalue must be const int *; its value should either be LDAP_OPT_OFF or LDAP_OPT_ON. outvalue must be int *.
Sets/gets the LDAP result code associated to the handle. This option was formerly known as LDAP_OPT_ERROR_NUMBER. invalue must be a const int *. outvalue must be a int *.
Sets/gets the server-side controls to be used for all operations. This is now deprecated as modern LDAP C API provides replacements for all main operations which accepts server-side controls as explicit arguments; see for example ldap_search_ext(3), ldap_add_ext(3), ldap_modify_ext(3) and so on. outvalue must be LDAPControl ***, and the caller is responsible of freeing the returned controls, if any, by calling ldap_controls_free(3), while invalue must be LDAPControl *const *; the library duplicates the controls passed via invalue.
Returns the reference count associated with the LDAP handle passed in as ld; outvalue must be a int *. This is a read-only, handle-specific option. This option is OpenLDAP specific.
Sets/gets the value that defines the maximum number of entries to be returned by a search operation. invalue must be const int *, while outvalue must be int *; They cannot be NULL.
Returns a pointer to the socket buffer of the LDAP handle passed in as ld; outvalue must be a Sockbuf **. This is a read-only, handle-specific option. This option is OpenLDAP specific.
Sets/gets a space-separated list of IP Addresses used as binding interface to remote server when trying to establish a connection. Only one valid IPv4 address and/or one valid IPv6 address are allowed in the list. outvalue must be a char **, and the caller is responsible of freeing the returned string by calling ldap_memfree(3), while invalue must be a const char *; the library duplicates the corresponding string.
Sets/gets the value that defines the time limit after which a search operation should be terminated by the server. invalue must be const int *, while outvalue must be int *, and they cannot be NULL.
Sets/gets a timeout value for the synchronous API calls. outvalue must be a struct timeval ** (the caller has to free *outvalue using ldap_memfree(3)), and invalue must be a struct timeval *, and they cannot be NULL. Using a struct with seconds set to -1 results in an infinite timeout, which is the default. This option is OpenLDAP specific.
Sets/gets a comma- or space-separated list of URIs to be contacted by the library when trying to establish a connection. outvalue must be a char **, and the caller is responsible of freeing the resulting string by calling ldap_memfree(3), while invalue must be a const char *; the library parses the string into a list of LDAPURLDesc structures, so the invocation of ldap_set_option(3) may fail if URL parsing fails. URIs may only contain the schema, the host, and the port fields. This option is OpenLDAP specific.
Instructs ldap_result(3) to keep the connection open on read error or if Notice of Disconnection is received. In these cases, the connection should be closed by the caller. This option is OpenLDAP specific.
Allows to configure TCP_USER_TIMEOUT in milliseconds on the connection, overriding the operating system setting. This option is OpenLDAP specific and supported only on Linux 2.6.37 or higher. invalue must be a const unsigned int *; outvalue must be an unsigned int *.

SASL OPTIONS

The SASL options are OpenLDAP specific and unless otherwise noted, require an LDAP handle to be passed.

Gets the SASL authentication identity; outvalue must be a char **, its content needs to be freed by the caller using ldap_memfree(3).
Gets the SASL authorization identity; outvalue must be a char **, its content needs to be freed by the caller using ldap_memfree(3).
Gets/sets SASL maximum buffer size; invalue must be const ber_len_t *, while outvalue must be ber_len_t *. See also LDAP_OPT_X_SASL_SECPROPS.
Gets the SASL mechanism; outvalue must be a char **, its content needs to be freed by the caller using ldap_memfree(3).
Gets the list of the available mechanisms, in form of a NULL-terminated array of strings; outvalue must be char ***. The caller must not free or otherwise muck with it. This option can be used globally.
Sets/gets the NOCANON flag. When unset, the hostname is canonicalized. invalue must be const int *; its value should either be LDAP_OPT_OFF or LDAP_OPT_ON. outvalue must be int *.
Gets the SASL realm; outvalue must be a char **, its content needs to be freed by the caller using ldap_memfree(3).
Sets the SASL secprops; invalue must be a char *, containing a comma-separated list of properties. Legal values are: none, nodict, noplain, noactive, passcred, forwardsec, noanonymous, minssf=<minssf>, maxssf=<maxssf>, maxbufsize=<maxbufsize>.
Gets the SASL SSF; outvalue must be a ber_len_t *.
Sets the SASL SSF value related to an authentication performed using an EXTERNAL mechanism; invalue must be a const ber_len_t *.
Gets/sets SASL maximum SSF; invalue must be const ber_len_t *, while outvalue must be ber_len_t *. See also LDAP_OPT_X_SASL_SECPROPS.
Gets/sets SASL minimum SSF; invalue must be const ber_len_t *, while outvalue must be ber_len_t *. See also LDAP_OPT_X_SASL_SECPROPS.
Gets the SASL username; outvalue must be a char **. Its content needs to be freed by the caller using ldap_memfree(3).
Sets/gets the channel-binding type to use in SASL, one of LDAP_OPT_X_SASL_CBINDING_NONE (the default), LDAP_OPT_X_SASL_CBINDING_TLS_UNIQUE the "tls-unique" type from RFC 5929. LDAP_OPT_X_SASL_CBINDING_TLS_ENDPOINT the "tls-server-end-point" from RFC 5929, compatible with Windows. invalue must be const int *; outvalue must be int *.

TCP OPTIONS

The TCP options are OpenLDAP specific. Mainly intended for use with Linux, they may not be portable.

Sets/gets the number of seconds a connection needs to remain idle before TCP starts sending keepalive probes. invalue must be const int *; outvalue must be int *.
Sets/gets the maximum number of keepalive probes TCP should send before dropping the connection. invalue must be const int *; outvalue must be int *.
Sets/gets the interval in seconds between individual keepalive probes. invalue must be const int *; outvalue must be int *.

TLS OPTIONS

The TLS options are OpenLDAP specific.

Sets/gets the path of the directories containing CA certificates. Multiple directories may be specified, separated by a semi-colon. invalue must be const char *; outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3).
Sets/gets the full-path of the CA certificate file. invalue must be const char *; outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3).
Sets/gets the full-path of the certificate file. invalue must be const char *; outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3).
Gets the cipher being used on an established TLS session. outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3).
Sets/gets the allowed cipher suite. invalue must be const char *; outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3).
Sets/gets the connection callback argument. invalue must be const void *; outvalue must be void **.
Sets/gets the connection callback handle. invalue must be const LDAP_TLS_CONNECT_CB *; outvalue must be LDAP_TLS_CONNECT_CB **.
Sets/gets the CRL evaluation strategy, one of LDAP_OPT_X_TLS_CRL_NONE, LDAP_OPT_X_TLS_CRL_PEER, or LDAP_OPT_X_TLS_CRL_ALL. invalue must be const int *; outvalue must be int *. Requires OpenSSL.
Sets/gets the full-path of the CRL file. invalue must be const char *; outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3). This option is only valid for GnuTLS.
Sets/gets the TLS library context. New TLS sessions will inherit their default settings from this library context. invalue must be const void *; outvalue must be void **. When using the OpenSSL library this is an SSL_CTX*. When using other crypto libraries this is a pointer to an OpenLDAP private structure. Applications generally should not use this option or attempt to manipulate this structure.
Gets/sets the full-path of the file containing the parameters for Diffie-Hellman ephemeral key exchange. invalue must be const char *; outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3).
Gets/sets the name of the curve(s) used for elliptic curve key exchanges. invalue must be const char *; outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3). Ignored by GnuTLS. In GnuTLS a curve may be selected in the cipher suite specification.
Sets/gets the full-path of the certificate key file. invalue must be const char *; outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3).
Instructs the library to create a new TLS library context. invalue must be const int *. A non-zero value pointed to by invalue tells the library to create a context for a server.
Gets the peer's certificate in DER format from an established TLS session. outvalue must be struct berval *, and the data it returns needs to be freed by the caller using ldap_memfree(3).
Sets/gets the maximum protocol version. invalue must be const int *; outvalue must be int *.
Sets/gets the minimum protocol version. invalue must be const int *; outvalue must be int *.
Sets/gets the random file when /dev/random and /dev/urandom are not available. invalue must be const char *; outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3). Ignored by GnuTLS older than version 2.2.
Sets/gets the peer certificate checking strategy, one of LDAP_OPT_X_TLS_NEVER, LDAP_OPT_X_TLS_HARD, LDAP_OPT_X_TLS_DEMAND, LDAP_OPT_X_TLS_ALLOW, LDAP_OPT_X_TLS_TRY.
Sets/gets the peer certificate subjectAlternativeName checking strategy, one of LDAP_OPT_X_TLS_NEVER, LDAP_OPT_X_TLS_HARD, LDAP_OPT_X_TLS_DEMAND, LDAP_OPT_X_TLS_ALLOW, LDAP_OPT_X_TLS_TRY.
Gets the TLS session context associated with this handle. outvalue must be void **. When using the OpenSSL library this is an SSL*. When using other crypto libraries this is a pointer to an OpenLDAP private structure. Applications generally should not use this option.
Gets the TLS version being used on an established TLS session. outvalue must be char **, and its contents need to be freed by the caller using ldap_memfree(3).
Sets the (public) key that the application expects the peer to be using. invalue must be const char * containing the base64 encoding of the expected peer's key or in the format <hashalg>:<peerkey hash base64 encoded> where as a TLS session is established, the library will hash the peer's key with the provided hash algorithm and compare it with value provided and will only allow the session to continue if they match. This happens regardless of certificate checking strategy. The list of supported hashalg values depends on the crypto library used, check its documentation to get a list.

ERRORS

On success, the functions return LDAP_OPT_SUCCESS, while they may return LDAP_OPT_ERROR to indicate a generic option handling error. Occasionally, more specific errors can be returned, like LDAP_NO_MEMORY to indicate a failure in memory allocation.

NOTES

The LDAP libraries with the LDAP_OPT_REFERRALS option set to LDAP_OPT_ON (default value) automatically follow referrals using an anonymous bind. Application developers are encouraged to either implement consistent referral chasing features, or explicitly disable referral chasing by setting that option to LDAP_OPT_OFF.

The protocol version used by the library defaults to LDAPv2 (now historic), which corresponds to the LDAP_VERSION2 macro. Application developers are encouraged to explicitly set LDAP_OPT_PROTOCOL_VERSION to LDAPv3, using the LDAP_VERSION3 macro, or to allow users to select the protocol version.

SEE ALSO

ldap(3), ldap_error(3), RFC 4422 (http://www.rfc-editor.org),

ACKNOWLEDGEMENTS

OpenLDAP Software is developed and maintained by The OpenLDAP Project <http://www.openldap.org/>. OpenLDAP Software is derived from the University of Michigan LDAP 3.3 Release.

2024/05/21 OpenLDAP 2.6.8