SSL_CTRL_GET_EXTRA_CHAIN_CERTS
SSL_CTX_ctrl(ctx, SSL_CTRL_GET_EXTRA_CHAIN_CERTS, 0, px509)
SSL_CTX_ctrl(ctx, SSL_CTRL_GET_EXTRA_CHAIN_CERTS, 1, px509)
case SSL_CTRL_GET_EXTRA_CHAIN_CERTS: