Struct TxState

pub struct TxState<'a> {
    pub dst_pan: Cell<PanID>,
    /* private fields */
}

Tracks the compression state for a single IPv6 packet.

When an upper layer is interested in sending a packet using Sixlowpan, they must first call TxState.init, which initializes the compression state for a new packet. The upper layer then repeatedly calls TxState.next_fragment until there are no more frames to compress. Note that the upper layer is responsible for sending the compressed frames; the TxState struct simply produces compressed MAC frames.

Fields

dst_pan: Cell<PanID>

State for the current transmission

Implementations

impl<'a> TxState<'a>

pub fn new(sixlowpan: &'a dyn SixlowpanState<'a>) -> TxState<'a>

Creates a new TxState

Arguments

sixlowpan - A reference to a SixlowpanState object, which contains global state for the entire Sixlowpan layer.

pub fn init( &self, src_mac_addr: MacAddress, dst_mac_addr: MacAddress, radio_pan: u16, security: Option<(SecurityLevel, KeyId)>, ) -> Result<(), ErrorCode>

Initializes TxState for a new packet

Arguments

src_mac_addr - The MAC address the frame will be sent from dst_mac_addr - The MAC address the frame will be sent to radio_pan - The PAN ID held by the radio underlying this stack security - Any security options (necessary since the size of the produced MAC frame is dependent on the security options)

Return Value

This function returns a Result<(), ErrorCode>, which indicates success or failure. Note that if init has already been called and we are currently sending a packet, this function will return Err(ErrorCode::BUSY)

pub fn next_fragment<'b>( &self, ip6_packet: &'b IP6Packet<'b>, frag_buf: &'static mut [u8], radio: &dyn MacDevice<'_>, ) -> Result<(bool, Frame), (Result<(), ErrorCode>, &'static mut [u8])>

Gets the next 6LoWPAN Fragment (as a MAC frame) to be sent. Note that this layer does not send the frame, and assumes that init has already been called.

Arguments

ip6_packet - A reference to the IPv6 packet to be compressed frag_buf - The buffer to write the MAC frame to radio - A reference to a MacDevice, which is used to prepare the MAC frame

Return Value

This function returns a Result type: Ok(bool, frame) - If Ok, then bool indicates whether the transmission is complete, and Frame is the filled out next MAC frame Err(Result<(), ErrorCode>, &'static mut [u8]) - If Err, then Result<(), ErrorCode> is the reason for the error, and the return buffer is the (non-consumed) frag_buf passed in as an argument