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|
use crate::rtp::SSRC;
#[derive(Debug, thiserror::Error)]
pub enum Error {
#[error("packet truncated")]
Truncated,
#[error("unsupported version")]
Version,
}
pub struct RtcpPacket<'a> {
pub parts: Vec<RtcpPart<'a>>,
}
pub enum RtcpPart<'a> {
SenderReport(SenderReport<'a>),
ReceiverReport(ReceiverReport),
SourceDescription(SourceDescription),
Bye(Bye<'a>),
Application(Application<'a>),
}
pub struct SenderReport<'a> {
pub ssrc: SSRC,
pub sender_info: SenderInfo,
pub reports: Vec<ReportBlock>,
pub extension: &'a [u8],
}
pub struct ReceiverReport {
pub sender_ssrc: SSRC,
pub reports: Vec<ReportBlock>,
}
pub struct SourceDescription {
pub sources: Vec<(SSRC, Vec<(SdesType, String)>)>,
}
#[derive(Debug, Clone, Copy)]
pub enum SdesType {
CanonicalName = 1,
Name = 2,
Email = 3,
Phone = 4,
Location = 5,
Tool = 6,
Notice = 7,
PrivateExtension = 8,
}
pub struct Bye<'a> {
pub ssrcs: Vec<SSRC>,
pub reason: &'a [u8],
}
pub struct Application<'a> {
pub subtype: u8,
pub name: [u8; 4],
pub ssrc: SSRC,
pub data: &'a [u8],
}
pub struct SenderInfo {
pub ntp_ts: u64,
pub rtp_ts: u32,
pub packet_count: u32,
pub octet_count: u32,
}
pub struct ReportBlock {
pub ssrc: SSRC,
pub fraction_lost: u8,
pub cumulative_packets_lost: u32,
pub ext_max_seq_num_recv: u32,
pub interarrical_jitter: u32,
pub lsr: u32,
pub dlsr: u32,
}
impl<'a> RtcpPacket<'a> {
pub fn parse(mut packet: &'a [u8]) -> Result<RtcpPacket<'a>, Error> {
let mut parts = Vec::with_capacity(2);
while packet.len() > 0 {
if packet.len() < 4 {
return Err(Error::Truncated);
}
let version = (packet[0] & 0b11000000) >> 6;
if !matches!(version, 1 | 2) {
return Err(Error::Version);
}
let padding = (packet[0] & 0b00100000) != 0;
let num_reports = (packet[0] & 0b00011111) >> 0;
let packet_type = packet[1];
let length = u16::from_be_bytes([packet[2], packet[3]]);
match packet_type {
200 => {
// sender seport
if packet.len() < 28 + 24 * num_reports as usize {
return Err(Error::Truncated);
}
let ssrc = SSRC(u32::from_be_bytes(packet[4..8].try_into().unwrap()));
let sender_info = SenderInfo::parse(packet[8..28].try_into().unwrap());
let mut reports = Vec::with_capacity(num_reports as usize);
for n in 0..num_reports as usize {
reports.push(ReportBlock::parse(
packet[28 + 24 * n..28 + 24 * (n + 1)].try_into().unwrap(),
));
}
let extension = &packet[28 + 24 * num_reports as usize..];
parts.push(RtcpPart::SenderReport(SenderReport {
reports,
sender_info,
ssrc,
extension,
}))
}
201 => {
// receiver report
}
202 => {
// source description
}
203 => {
// bye
}
204 => {
// application defined
}
_ => {}
}
packet = &packet[length as usize..];
}
Ok(Self { parts })
}
pub fn write(&self, out: &mut Vec<u8>) {
for part in &self.parts {
let version = 2;
let padding = false;
match part {
RtcpPart::SenderReport(sender_report) => {
out.push(
version << 6 | (padding as u8) << 5 | sender_report.reports.len() as u8,
);
out.push(200);
todo!()
}
RtcpPart::ReceiverReport(receiver_report) => {
out.push(
version << 6 | (padding as u8) << 5 | receiver_report.reports.len() as u8,
);
out.push(201);
out.extend(((receiver_report.reports.len() * 6 + 1) as u16).to_be_bytes());
out.extend(receiver_report.sender_ssrc.0.to_be_bytes());
for r in &receiver_report.reports {
r.write(out);
}
}
RtcpPart::SourceDescription(source_description) => {
out.push(
version << 6
| (padding as u8) << 5
| source_description.sources.len() as u8,
);
out.push(202);
let mut buf = Vec::new();
for (ssrc, items) in &source_description.sources {
buf.extend(ssrc.0.to_be_bytes());
for (ty, name) in items {
buf.push(*ty as u8);
buf.push(name.len() as u8);
buf.extend(name.as_bytes());
}
while buf.len() % 4 != 0 {
buf.push(0);
}
}
out.extend(((buf.len() / 4) as u16).to_be_bytes());
out.extend(buf);
}
RtcpPart::Bye(bye) => todo!(),
RtcpPart::Application(application) => {
assert!(application.data.len() % 4 == 0, "todo");
out.push(version << 6 | (padding as u8) << 5 | application.subtype);
out.push(204);
out.extend(((application.data.len() / 4 + 2) as u16).to_be_bytes());
out.extend(application.ssrc.0.to_be_bytes());
out.extend(application.name);
out.extend(application.data);
}
}
}
}
}
impl SenderInfo {
pub const SIZE: usize = 5 * 4;
pub fn parse(packet: [u8; 5 * 4]) -> SenderInfo {
Self {
ntp_ts: u64::from_be_bytes(packet[0..8].try_into().unwrap()),
rtp_ts: u32::from_be_bytes(packet[8..12].try_into().unwrap()),
packet_count: u32::from_be_bytes(packet[12..16].try_into().unwrap()),
octet_count: u32::from_be_bytes(packet[16..20].try_into().unwrap()),
}
}
pub fn write(&self, out: &mut Vec<u8>) {
out.extend(self.ntp_ts.to_be_bytes());
out.extend(self.rtp_ts.to_be_bytes());
out.extend(self.packet_count.to_be_bytes());
out.extend(self.octet_count.to_be_bytes());
}
}
impl ReportBlock {
pub fn parse(packet: [u8; 6 * 4]) -> ReportBlock {
Self {
ssrc: SSRC(u32::from_be_bytes(packet[0..4].try_into().unwrap())),
fraction_lost: packet[4],
cumulative_packets_lost: u32::from_be_bytes([0, packet[5], packet[6], packet[7]]),
ext_max_seq_num_recv: u32::from_be_bytes(packet[8..12].try_into().unwrap()),
interarrical_jitter: u32::from_be_bytes(packet[12..16].try_into().unwrap()),
lsr: u32::from_be_bytes(packet[16..20].try_into().unwrap()),
dlsr: u32::from_be_bytes(packet[20..24].try_into().unwrap()),
}
}
pub fn write(&self, out: &mut Vec<u8>) {
out.extend(self.ssrc.0.to_be_bytes());
out.push(self.fraction_lost);
out.extend(&self.cumulative_packets_lost.to_be_bytes()[1..]);
out.extend(self.ext_max_seq_num_recv.to_be_bytes());
out.extend(self.interarrical_jitter.to_be_bytes());
out.extend(self.lsr.to_be_bytes());
out.extend(self.dlsr.to_be_bytes());
}
}
|
