Enum SessionRequest

pub enum SessionRequest {
    Attach {
        port: PortId,
        rx_frames: Vec<FrameType>,
        responder: SessionAttachResponder,
    },
    Detach {
        port: PortId,
        responder: SessionDetachResponder,
    },
    Close {
        control_handle: SessionControlHandle,
    },
    WatchDelegatedRxLease {
        responder: SessionWatchDelegatedRxLeaseResponder,
    },
}

Represents a session with a Network device.

A session has a data plane and a control plane. The Session protocol represents the control plane of the session and the FIFOs and VMOs exchanged during the [Device.OpenSession] call are the data plane. Lifetime of the session is controlled by a Session protocol handle.

Sessions must attach to ports of interest to start receiving and sending data. Sessions are always created with no ports attached.

If a port is destroyed from the underlying device, it is automatically detached from the session.

Inbound traffic is dispatched to all open sessions. Devices typically operate with a single primary session, see [SessionFlags.PRIMARY]. Each additional open session to the same device causes data copy overhead on the device’s data path.

The session is closed with an error epitaph if an invalid buffer descriptor is sent over either the tx or rx FIFOs. Invalid descriptors include:

• Descriptor index larger than [SessionInfo.descriptor_count].
• Descriptor chains larger than MAX_DESCRIPTOR_CHAIN.
• rx buffers smaller than [Info.min_rx_buffer_length].
• tx buffers smaller than [Info.min_tx_buffer_length].
• tx buffers not respecting [Info.min_tx_buffer_head] or [Info.min_tx_buffer_tail].

Variants

Attach

Attaches the session to port.

Once attached, the session starts to receive the subscribed frames over the data FIFOs and it may send frames destined to the specified port.

• request port port to subscribe to.
• request rx_frames Frame types of interest on the port.

• error ZX_ERR_NOT_FOUND if port is not valid.
• error ZX_ERR_INVALID_ARGS if rx_frames is not a subset of the port’s supported frames.
• error ZX_ERR_ALREADY_BOUND if port is already attached.

Fields

port: PortId

rx_frames: Vec<FrameType>

responder: SessionAttachResponder

Detach

Detaches the session from port.

Once detached, the session stops receiving frames from port. Frames sent to a detached port may be returned with an error. It is not necessary to call Detach on ports that are removed from the device, doing so causes ZX_ERR_NOT_FOUND to be returned.

• request port port to subscribe to.

• error ZX_ERR_NOT_FOUND if the session is not currently attached to the port.

Fields

port: PortId

responder: SessionDetachResponder

Close

Cleanly closes a session.

This will cause the session to send a ZX_ERR_CANCELLED epitaph and proceed to close the Session channel. Clients may only assume that they own all the buffers that are currently owned by the session (sent over either the rx or tx FIFOs) once the epitaph is received. Closing the rx or tx FIFO is equivalent to calling Close.

Fields

control_handle: SessionControlHandle

WatchDelegatedRxLease

Watchers for delegated receive wakeup leases.

Calls block until a lease is delegated by the device. If a call to WatchDelegatedRxLease is made while a previous call is blocking, the session is closed with ZX_ERR_BAD_STATE. Will never yield any values for sessions created without [SessionFlags.RECEIVE_RX_POWER_LEASES].

Given a single lease is assumed sufficient to keep the system awake, the server only keeps a single lease in its buffer. If a new delegated lease becomes available and the client hasn’t popped the previous one with a call to WatchDelegatedRxLease, the server drops the previously pending lease.

See DelegatedRxLease for how to handle delegated leases.

Fields

responder: SessionWatchDelegatedRxLeaseResponder

Implementations

impl SessionRequest

pub fn into_attach( self, ) -> Option<(PortId, Vec<FrameType>, SessionAttachResponder)>

pub fn into_detach(self) -> Option<(PortId, SessionDetachResponder)>

pub fn into_close(self) -> Option<SessionControlHandle>

pub fn into_watch_delegated_rx_lease( self, ) -> Option<SessionWatchDelegatedRxLeaseResponder>

pub fn method_name(&self) -> &'static str

Name of the method defined in FIDL

Trait Implementations

impl Debug for SessionRequest

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.