@deftypefun {int} {dane_verify_crt} (dane_state_t @var{s}, const gnutls_datum_t * @var{chain}, unsigned @var{chain_size}, gnutls_certificate_type_t @var{chain_type}, const char * @var{hostname}, const char * @var{proto}, unsigned int @var{port}, unsigned int @var{sflags}, unsigned int @var{vflags}, unsigned int * @var{verify})
@var{s}: A DANE state structure (may be NULL)

@var{chain}: A certificate chain

@var{chain_size}: The size of the chain

@var{chain_type}: The type of the certificate chain

@var{hostname}: The hostname associated with the chain

@var{proto}: The protocol of the service connecting (e.g. tcp)

@var{port}: The port of the service connecting (e.g. 443)

@var{sflags}: Flags for the initialization of  @code{s} (if NULL)

@var{vflags}: Verification flags; an OR'ed list of @code{dane_verify_flags_t} .

@var{verify}: An OR'ed list of @code{dane_verify_status_t} .

This function will verify the given certificate chain against the
CA constrains and/or the certificate available via DANE.
If no information via DANE can be obtained the flag @code{DANE_VERIFY_NO_DANE_INFO} 
is set. If a DNSSEC signature is not available for the DANE
record then the verify flag @code{DANE_VERIFY_NO_DNSSEC_DATA}  is set.

Due to the many possible options of DANE, there is no single threat
model countered. When notifying the user about DANE verification results
it may be better to mention: DANE verification did not reject the certificate,
rather than mentioning a successful DANE verication.

Note that this function is designed to be run in addition to
PKIX - certificate chain - verification. To be run independently
the @code{DANE_VFLAG_ONLY_CHECK_EE_USAGE}  flag should be specified;
then the function will check whether the key of the peer matches the
key advertized in the DANE entry.

@strong{Returns:} a negative error code on error and @code{DANE_E_SUCCESS}  (0)
when the DANE entries were successfully parsed, irrespective of
whether they were verified (see  @code{verify} for that information). If
no usable entries were encountered @code{DANE_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.
@end deftypefun