Register older‐style custom extension handlers for TLS/DTLS clients.

Synopsis

Declared in <openssl/ssl.h>

int
SSL_CTX_add_client_custom_ext(
    SSL_CTX* ctx,
    unsigned int ext_type,
    custom_ext_add_cb add_cb,
    custom_ext_free_cb free_cb,
    void* add_arg,
    custom_ext_parse_cb parse_cb,
    void* parse_arg);

Return Value

1 on success, or 0 on error.

Parameters

Name

Description

ctx

SSL context used by clients.

ext_type

Extension type (not a NID); must not be handled internally by OpenSSL.

add_cb

Callback that supplies extension data to send, or NULL for a zero‐length ClientHello extension.

free_cb

Optional callback to free data produced by add_cb.

add_arg

Application argument passed to add_cb and free_cb.

parse_cb

Callback that validates extension data received from the peer.

parse_arg

Application argument passed to parse_cb.

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