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// Copyright 2024, The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use crate::reader::{unpack, Reader};
use crate::writer::{pack, Write, Writer};
/// 5.4.5 ISO Data Packets
/// Exchange of Isochronous Data between the Host and Controller
#[derive(Debug)]
pub struct IsoData<'a> {
/// Identify the connection
pub connection_handle: u16,
/// Fragmentation of the packet
pub sdu_fragment: IsoSduFragment,
/// Payload
pub payload: &'a [u8],
}
/// Fragmentation indication of the SDU
#[derive(Debug)]
pub enum IsoSduFragment {
/// First SDU Fragment
First {
/// SDU Header
hdr: IsoSduHeader,
/// Last SDU fragment indication
is_last: bool,
},
/// Continuous fragment
Continue {
/// Last SDU fragment indication
is_last: bool,
},
}
/// SDU Header information, when ISO Data in a first SDU fragment
#[derive(Debug, Default)]
pub struct IsoSduHeader {
/// Optional timestamp in microseconds
pub timestamp: Option<u32>,
/// Sequence number of the SDU
pub sequence_number: u16,
/// Total length of the SDU (sum of all fragments)
pub sdu_length: u16,
/// Only valid from Controller, indicate valid SDU data when 0
pub status: u16,
}
impl<'a> IsoData<'a> {
/// Read an HCI ISO Data packet
pub fn from_bytes(data: &'a [u8]) -> Option<Self> {
Self::parse(&mut Reader::new(data))
}
/// Output the HCI ISO Data packet
pub fn to_bytes(&self) -> Vec<u8> {
let mut w = Writer::new(Vec::with_capacity(12 + self.payload.len()));
w.write(self);
w.into_vec()
}
/// New ISO Data packet, including a complete SDU
pub fn new(connection_handle: u16, sequence_number: u16, data: &'a [u8]) -> Self {
Self {
connection_handle,
sdu_fragment: IsoSduFragment::First {
hdr: IsoSduHeader {
sequence_number,
sdu_length: data.len().try_into().unwrap(),
..Default::default()
},
is_last: true,
},
payload: data,
}
}
fn parse(r: &mut Reader<'a>) -> Option<Self> {
let (connection_handle, pb_flag, ts_present) = unpack!(r.read_u16()?, (12, 2, 1));
let data_len = unpack!(r.read_u16()?, 14) as usize;
let sdu_fragment = match pb_flag {
0b00 => IsoSduFragment::First {
hdr: IsoSduHeader::parse(r, ts_present != 0)?,
is_last: false,
},
0b10 => IsoSduFragment::First {
hdr: IsoSduHeader::parse(r, ts_present != 0)?,
is_last: true,
},
0b01 => IsoSduFragment::Continue { is_last: false },
0b11 => IsoSduFragment::Continue { is_last: true },
_ => unreachable!(),
};
let sdu_header_len = Self::sdu_header_len(&sdu_fragment);
if data_len < sdu_header_len {
return None;
}
Some(Self { connection_handle, sdu_fragment, payload: r.get(data_len - sdu_header_len)? })
}
fn sdu_header_len(sdu_fragment: &IsoSduFragment) -> usize {
match sdu_fragment {
IsoSduFragment::First { ref hdr, .. } => 4 * (1 + hdr.timestamp.is_some() as usize),
IsoSduFragment::Continue { .. } => 0,
}
}
}
impl Write for IsoData<'_> {
fn write(&self, w: &mut Writer) {
let (pb_flag, hdr) = match self.sdu_fragment {
IsoSduFragment::First { ref hdr, is_last: false } => (0b00, Some(hdr)),
IsoSduFragment::First { ref hdr, is_last: true } => (0b10, Some(hdr)),
IsoSduFragment::Continue { is_last: false } => (0b01, None),
IsoSduFragment::Continue { is_last: true } => (0b11, None),
};
let ts_present = hdr.is_some() && hdr.unwrap().timestamp.is_some();
w.write_u16(pack!((self.connection_handle, 12), (pb_flag, 2), ((ts_present as u16), 1)));
let packet_len = Self::sdu_header_len(&self.sdu_fragment) + self.payload.len();
w.write_u16(pack!(u16::try_from(packet_len).unwrap(), 14));
if let Some(hdr) = hdr {
w.write(hdr);
}
w.put(self.payload);
}
}
impl IsoSduHeader {
fn parse(r: &mut Reader, ts_present: bool) -> Option<Self> {
let timestamp = match ts_present {
true => Some(r.read_u32::<4>()?),
false => None,
};
let sequence_number = r.read_u16()?;
let (sdu_length, _, status) = unpack!(r.read_u16()?, (12, 2, 2));
Some(Self { timestamp, sequence_number, sdu_length, status })
}
}
impl Write for IsoSduHeader {
fn write(&self, w: &mut Writer) {
if let Some(timestamp) = self.timestamp {
w.write_u32::<4>(timestamp);
};
w.write_u16(self.sequence_number);
w.write_u16(pack!((self.sdu_length, 12), (0, 2), (self.status, 2)));
}
}
#[test]
fn test_iso_data() {
let dump = [
0x60, 0x60, 0x80, 0x00, 0x4d, 0xc8, 0xd0, 0x2f, 0x19, 0x03, 0x78, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0xe0, 0x93, 0xe5, 0x28, 0x34, 0x00, 0x00, 0x04,
];
let Some(pkt) = IsoData::from_bytes(&dump) else { panic!() };
assert_eq!(pkt.connection_handle, 0x060);
let IsoSduFragment::First { ref hdr, is_last } = pkt.sdu_fragment else { panic!() };
assert_eq!(hdr.timestamp, Some(802_211_917));
assert_eq!(hdr.sequence_number, 793);
assert_eq!(hdr.sdu_length, 120);
assert!(is_last);
assert_eq!(
pkt.payload,
&[
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0xe0, 0x93, 0xe5, 0x28, 0x34, 0x00, 0x00, 0x04
]
);
assert_eq!(pkt.to_bytes(), &dump[..]);
}
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