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tls_client - Man Page

configure a TLS connection


#include <tls.h>

struct tls *

struct tls *

tls_configure(struct tls *ctx, struct tls_config *config);

tls_free(struct tls *ctx);

tls_reset(struct tls *ctx);


A TLS connection is represented as a struct tls object called a “context”. A new context is created by either the tls_client() or tls_server() functions. tls_client() is used in TLS client programs, tls_server() in TLS server programs.

The context can then be configured with the function tls_configure(). The same tls_config object can be used to configure multiple contexts.

After configuration, tls_connect(3) can be called on objects created with tls_client(), and tls_accept_socket(3) on objects created with tls_server().

After use, a TLS context should be closed with tls_close(3), and then freed by calling tls_free(). If tls_free() is called with an argument of NULL, no action occurs.

A TLS context can be reset by calling tls_reset(), allowing for it to be reused. This is essentially equivalent to calling tls_free(), followed by a call to the same function that was used to originally allocate the TLS context.

Return Values

tls_client() and tls_server() return NULL on error or an out of memory condition.

tls_configure() returns 0 on success or -1 on error.

See Also

tls_accept_socket(3), tls_config_new(3), tls_connect(3), tls_init(3)


These functions appeared in OpenBSD 5.6 and got their final names in OpenBSD 5.7.


Joel Sing <jsing@openbsd.org>

Referenced By

tls_accept_socket(3), tls_config_set_session_id(3), tls_config_verify(3), tls_connect(3), tls_conn_version(3), tls_init(3), tls_load_file(3), tls_ocsp_process_response(3), tls_read(3).

The man pages tls_configure(3), tls_free(3) and tls_server(3) are aliases of tls_client(3).

August 12, 2017