Overhaul stats events: merge HTTP core events with a different IP version

[josecelano]

Change events from this:

bittorrent_http_tracker_core::statistics::event::Event:

pub enum Event {
    Tcp4Announce,
    Tcp4Scrape,
    Tcp6Announce,
    Tcp6Scrape,
}

To this:

pub enum Event {
    TcpAnnounce { connection: ConnectionContext },
    TcpScrape { connection: ConnectionContext },
}

pub struct ConnectionContext {
    pub client_ip_addr: IpAddr,
    pub server_socket_addr: SocketAddr,
}

[josecelano]

In the end, the code looks like the following:

pub enum Event {
    TcpAnnounce { connection: ConnectionContext },
    TcpScrape { connection: ConnectionContext },
}

pub struct ConnectionContext {
    client: ClientConnectionContext,
    server: ServerConnectionContext,
}

pub struct ClientConnectionContext {
    ip_addr: IpAddr,
    port: Option<u16>,
}

pub struct ServerConnectionContext {
    socket_addr: SocketAddr,
}

because the client's port might not be available. It requires to set the router in a way that you can get the connection info. It's available if you use the torrust-axum-http-tracker-server crate.

This is the layer in the axum router to get the connection info:

.layer(SecureClientIpSource::ConnectInfo.into_extension())