Function decompress

pub fn decompress(
    ctx_store: &dyn ContextStore,
    buf: &[u8],
    src_mac_addr: MacAddress,
    dst_mac_addr: MacAddress,
    out_buf: &mut [u8],
    dgram_size: u16,
    is_fragment: bool,
) -> Result<(usize, usize), ()>

Decompresses a 6loWPAN header into a full IPv6 header

This function decompresses the header found in buf and writes it out_buf. It does not, though, copy payload bytes or a non-compressed next header. As a result, the caller should copy the buf.len - consumed remaining bytes from buf to out_buf.

Note that in the case of fragmentation, the total length of the IPv6 packet cannot be inferred from a single frame, and is instead provided by the dgram_size field in the fragmentation header. Thus, if we are decompressing a fragment, we rely on the dgram_size field; otherwise, we infer the length from the size of buf.

Arguments

• ctx_store - ???

• buf - A slice containing the 6LowPAN packet along with its payload.

• src_mac_addr - the 16-bit MAC address of the frame sender.

• dst_mac_addr - the 16-bit MAC address of the frame receiver.

• out_buf - A buffer to write the output to. Must be at least large enough to store an IPv6 header (XX bytes).

• dgram_size - If is_fragment is true, this is used as the IPv6 packets total payload size. Otherwise, this is ignored.

• is_fragment - ???

Returns

Ok((consumed, written)) if decompression is successful.

• consumed is the number of header bytes consumed from the 6LoWPAN header

• written is the number of uncompressed header bytes written into out_buf.