This function sets a callback to be called in order to retrieve
the certificate to be used in the handshake. The callback will
take control only if a certificate is requested by the peer.
The callback's function prototype is: int
(*callback)(gnutls_session_t, const gnutls_datum_t* req_ca_dn,
int nreqs, const gnutls_pk_algorithm_t* pk_algos, int
pk_algos_length, gnutls_pcert_st** pcert, unsigned int
*pcert_length, gnutls_privkey_t * pkey);
req_ca_dn is only used in X.509 certificates. Contains 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
pk_algos contains a list with server's acceptable public key
algorithms. The certificate returned should support the server's
pcert should contain a single certificate and public key or a
list of them.
pcert_length is the size of the previous list.
pkey is the private key.
If the callback function is provided then gnutls will call it, in
the handshake, after the certificate request message has been
received. All the provided by the callback values will not be
released or modified by gnutls.
In server side pk_algos and req_ca_dn are NULL.
The callback function should set the certificate list to be sent,
and return 0 on success. If no certificate was selected then the
number of certificates should be set to zero. The 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 predence.
This page is part of the GnuTLS (GnuTLS Transport Layer Security
Library) project. Information about the project can be found at
⟨http://www.gnutls.org/⟩. If you have a bug report for this
manual page, send it to firstname.lastname@example.org. This page was obtained
from the tarball gnutls-3.7.2.tar.xz fetched from
⟨http://www.gnutls.org/download.html⟩ on 2021-08-27. If you
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