This function sets a callback to be called in order to retrieve
the certificate and OCSP responses to be used in the handshake.
func will be called only if the peer requests a certificate
either during handshake or during post-handshake authentication.
The callback's function prototype is defined in `abstract.h':
int gnutls_certificate_retrieve_function3( gnutls_session_t,
const struct gnutls_cert_retr_st *info, gnutls_pcert_st **certs,
unsigned int *certs_length, gnutls_ocsp_data_st **ocsp, unsigned
int *ocsp_length, gnutls_privkey_t *privkey, unsigned int
The info field of the callback contains:
req_ca_dn which is a list with the CA names that the server
considers trusted. This is a hint and typically the client
should send a certificate that is signed by one of these CAs.
These names, when available, are DER encoded. To get a more
meaningful value use the function gnutls_x509_rdn_get().
pk_algos contains a list with server's acceptable public key
algorithms. The certificate returned should support the server's
The callback should fill-in the following values:
certs should contain an allocated list of certificates and
certs_length is the size of the previous list.
ocsp should contain an allocated list of OCSP responses.
ocsp_length is the size of the previous list.
privkey is the private key.
If flags in the callback are set to GNUTLS_CERT_RETR_DEINIT_ALL
then all provided values must be allocated using gnutls_malloc(),
and will be released by gnutls; otherwise they will not be
touched by gnutls.
The callback function should set the certificate and OCSP
response list to be sent, and return 0 on success. If no
certificates are available, the certs_length and ocsp_length
should be set to zero. The return value (-1) indicates error and
the handshake will be terminated. If both certificates are set in
the credentials and a callback is available, the callback takes
Raw public-keys: In case raw public-keys are negotiated as
certificate type, certificates that would normally hold the
public-key material are not available. In that case,
certs contains an allocated list with only the public key. Since
there is no certificate, there is also no certificate status.
Therefore, OCSP information should not be set.
This page is part of the GnuTLS (GnuTLS Transport Layer Security
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⟨http://www.gnutls.org/⟩. If you have a bug report for this
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