Attribute Macro milter_callback::on_negotiate

#[on_negotiate]

Generates a callback function of type NegotiateCallback that delegates to the annotated function.

As its sole argument on_negotiate takes an identifier to be used as the name of the generated function.

The on_negotiate callback is called just before the connect stage. It enables negotiation of certain protocol features that apply to the current connection. The function arguments indicate what capabilities are available. The milter can then return a subset of these to signal the desired ones. The signature of the annotated function must be as specified below.

Arguments:

• Context<T> – the callback context
• Actions – the available actions
• ProtocolOpts – the available milter protocol options

Return type:

• a tuple containing the fields
  • Status – the response status. The special response status Status::AllOpts enables all available actions and protocol stages; use Status::Continue to apply your own set of actions and protocol options.
  • Actions – the desired actions
  • ProtocolOpts – the desired protocol options

Examples

use milter::{Actions, Context, ProtocolOpts, Status};

#[on_negotiate(negotiate_callback)]
fn handle_negotiate(
    context: Context<MyData>,
    actions: Actions,
    protocol_opts: ProtocolOpts,
) -> (Status, Actions, ProtocolOpts) {
    (Status::AllOpts, Default::default(), Default::default())
}