= nng_tls_config_ca_file(3tls)
//
// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
// Copyright 2018 Capitar IT Group BV <info@capitar.com>
//
// This document is supplied under the terms of the MIT License, a
// copy of which should be located in the distribution where this
// file was obtained (LICENSE.txt).  A copy of the license may also be
// found online at https://opensource.org/licenses/MIT.
//

== NAME

nng_tls_config_ca_file - load certificate authority from file

== SYNOPSIS

[source, c]
----
#include <nng/nng.h>
#include <nng/supplemental/tls/tls.h>

int nng_tls_config_ca_file(nng_tls_config *cfg, const char *path);
----

== DESCRIPTION

The `nng_tls_config_ca_file()` function configures the ((certificate authority))
certificate chain and optional revocation list by loading the certificates
(and revocation list if present) from a single named file.
The file must at least one X.509 certificate in
https://tools.ietf.org/html/rfc7468[PEM]
format, and may contain multiple such certificates, as well as zero or
more PEM CRL objects.
This information is used to validate certificates
that are presented by peers, when using the configuration _cfg_.

NOTE: Certificates *must* be configured when using the authentication mode
`NNG_TLS_AUTH_MODE_REQUIRED`.

TIP: This function may be called multiple times, to add additional chains
to a configuration, without affecting those added previously.

== RETURN VALUES

This function returns 0 on success, and non-zero otherwise.

== ERRORS

[horizontal]
`NNG_ENOMEM`:: Insufficient memory is available.
`NNG_EBUSY`:: The configuration _cfg_ is already in use, and cannot be modified.
`NNG_EINVAL`:: The contents of _path_ are invalid or do not contain a valid PEM certificate.
`NNG_ENOENT`:: The file _path_ does not exist.
`NNG_EPERM`:: The file _path_ is not readable.

== SEE ALSO

[.text-left]
xref:nng_strerror.3.adoc[nng_strerror(3)],
xref:nng_tls_config_alloc.3tls.adoc[nng_tls_config_alloc(3tls)],
xref:nng_tls_config_auth_mode.3tls.adoc[nng_tls_config_auth_mode(3tls)],
xref:nng_tls_config_ca_chain.3tls.adoc[nng_tls_config_ca_chain(3tls)],
xref:nng.7.adoc[nng(7)]