DUO(3)							   BSD Library Functions Manual 						    DUO(3)

NAME

     duo -- Duo authentication service

SYNOPSIS

     #include <duo.h>

     duo_t *
     duo_open(const char *ikey, const char *skey, const char *progname, const char *cafile);

     void
     duo_set_conv_funcs(duo_t *d, char *(*conv_prompt)(void *conv_arg, const char *, char *, size_t),
	 void (*conv_status)(void *conv_arg, const char *msg), void *conv_arg);

     void
     duo_set_host(duo_t *d, const char *hostname);

     void
     duo_set_ssl_verify(duo_t *d, int bool);

     duo_code_t
     duo_login(duo_t *d, const char *username, const char *client_ip, int flags, const char *command);

     const char *
     duo_geterr(duo_t *d);

     void
     duo_close(duo_t *d);

DESCRIPTION

     The duo API provides access to the Duo two-factor authentication service.

     duo_open() is used to obtain a handle to the Duo service.	ikey and skey are the required integration and secret keys, respectively, for a
     Duo customer account.  progname identifies the program to the Duo service.  cafile should be NULL or the pathname of a PEM-format CA certifi-
     cate to override the default.

     duo_set_conv_funcs() may be used to override the internal user conversation functions.  conv_prompt is called to present the user a login
     menu and prompt, and gather their response, returning buf or NULL on error. It may be set to NULL if automatic login is specified with
     DUO_FLAG_AUTO.  conv_status is called to display status messages to the user, and may be NULL if no status display is needed.  conv_arg is
     passed as the first argument to these conversation functions.

     duo_set_host() may be used to override the default Duo API host.

     duo_set_ssl_verify() may be used to override SSL certificate verification (enabled by default).

     duo_login() performs secondary authentication via the Duo service for the specified username.  client_ip is the source IP address of the con-
     nection to be authenticated, or NULL to specify the local host. The following bitmask values are defined for flags:

	   DUO_FLAG_AUTO     Attempt authentication without prompting the user, using their default out-of-band authentication factor.
	   DUO_FLAG_SYNC     Do not report incremental status during authentication (e.g. voice callback progress) - only issue one status message
			     per authentication attempt.

     If not NULL, the command to be authorized will be displayed during push authentication.

     duo_geterr() returns a description of the last-seen error on the specified Duo API handle. The returned constant string should not be modi-
     fied or freed by the caller.

     duo_close() closes and frees the specified Duo API handle.

RETURN VALUES

     duo_open() returns a pointer to the configured Duo API handle, or NULL on failure.

     duo_login() returns status codes of type duo_code_t, which may have the following values:

	   DUO_OK	     User authenticated
	   DUO_FAIL	     User failed to authenticate
	   DUO_ABORT	     User denied by policy
	   DUO_LIB_ERROR     Unexpected library error
	   DUO_CONN_ERROR    Duo service unreachable
	   DUO_CLIENT_ERROR  Invalid client parameters to API call
	   DUO_SERVER_ERROR  Duo service error

     In the event of a DUO_*_ERROR return, duo_geterr may be called to recover a human-readable error message.

     duo_geterr() returns a constant string which should not be modified or freed by the caller.

SEE ALSO

     pam_duo(8), login_duo(1)

AUTHORS

     Duo Security <duo_unix@duosecurity.com>

BSD
								 October 31, 2010							       BSD