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use crate::{error::Error, header::*, packet::*, util::*};
use util::marshal::{Marshal, MarshalSize, Unmarshal};
use anyhow::Result;
use bytes::{Buf, BufMut};
use std::any::Any;
use std::fmt;
pub(crate) const RECEPTION_REPORT_LENGTH: usize = 24;
pub(crate) const FRACTION_LOST_OFFSET: usize = 4;
pub(crate) const TOTAL_LOST_OFFSET: usize = 5;
pub(crate) const LAST_SEQ_OFFSET: usize = 8;
pub(crate) const JITTER_OFFSET: usize = 12;
pub(crate) const LAST_SR_OFFSET: usize = 16;
pub(crate) const DELAY_OFFSET: usize = 20;
/// A ReceptionReport block conveys statistics on the reception of RTP packets
/// from a single synchronization source.
#[derive(Debug, PartialEq, Default, Clone)]
pub struct ReceptionReport {
/// The SSRC identifier of the source to which the information in this
/// reception report block pertains.
pub ssrc: u32,
/// The fraction of RTP data packets from source SSRC lost since the
/// previous SR or RR packet was sent, expressed as a fixed point
/// number with the binary point at the left edge of the field.
pub fraction_lost: u8,
/// The total number of RTP data packets from source SSRC that have
/// been lost since the beginning of reception.
pub total_lost: u32,
/// The low 16 bits contain the highest sequence number received in an
/// RTP data packet from source SSRC, and the most significant 16
/// bits extend that sequence number with the corresponding count of
/// sequence number cycles.
pub last_sequence_number: u32,
/// An estimate of the statistical variance of the RTP data packet
/// interarrival time, measured in timestamp units and expressed as an
/// unsigned integer.
pub jitter: u32,
/// The middle 32 bits out of 64 in the NTP timestamp received as part of
/// the most recent RTCP sender report (SR) packet from source SSRC. If no
/// SR has been received yet, the field is set to zero.
pub last_sender_report: u32,
/// The delay, expressed in units of 1/65536 seconds, between receiving the
/// last SR packet from source SSRC and sending this reception report block.
/// If no SR packet has been received yet from SSRC, the field is set to zero.
pub delay: u32,
}
impl fmt::Display for ReceptionReport {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{:?}", self)
}
}
impl Packet for ReceptionReport {
fn header(&self) -> Header {
Header::default()
}
fn destination_ssrc(&self) -> Vec<u32> {
vec![]
}
fn raw_size(&self) -> usize {
RECEPTION_REPORT_LENGTH
}
fn as_any(&self) -> &dyn Any {
self
}
fn equal(&self, other: &dyn Packet) -> bool {
other
.as_any()
.downcast_ref::<ReceptionReport>()
.map_or(false, |a| self == a)
}
fn cloned(&self) -> Box<dyn Packet> {
Box::new(self.clone())
}
}
impl MarshalSize for ReceptionReport {
fn marshal_size(&self) -> usize {
let l = self.raw_size();
// align to 32-bit boundary
l + get_padding_size(l)
}
}
impl Marshal for ReceptionReport {
/// marshal_to encodes the ReceptionReport in binary
fn marshal_to(&self, mut buf: &mut [u8]) -> Result<usize> {
/*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
* | SSRC |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | fraction lost | cumulative number of packets lost |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | extended highest sequence number received |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | interarrival jitter |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | last SR (LSR) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | delay since last SR (DLSR) |
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
*/
if buf.remaining_mut() < self.marshal_size() {
return Err(Error::BufferTooShort.into());
}
buf.put_u32(self.ssrc);
buf.put_u8(self.fraction_lost);
// pack TotalLost into 24 bits
if self.total_lost >= (1 << 25) {
return Err(Error::InvalidTotalLost.into());
}
buf.put_u8(((self.total_lost >> 16) & 0xFF) as u8);
buf.put_u8(((self.total_lost >> 8) & 0xFF) as u8);
buf.put_u8((self.total_lost & 0xFF) as u8);
buf.put_u32(self.last_sequence_number);
buf.put_u32(self.jitter);
buf.put_u32(self.last_sender_report);
buf.put_u32(self.delay);
put_padding(buf, self.raw_size());
Ok(self.marshal_size())
}
}
impl Unmarshal for ReceptionReport {
/// unmarshal decodes the ReceptionReport from binary
fn unmarshal<B>(raw_packet: &mut B) -> Result<Self>
where
Self: Sized,
B: Buf,
{
let raw_packet_len = raw_packet.remaining();
if raw_packet_len < RECEPTION_REPORT_LENGTH {
return Err(Error::PacketTooShort.into());
}
/*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
* | SSRC |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | fraction lost | cumulative number of packets lost |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | extended highest sequence number received |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | interarrival jitter |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | last SR (LSR) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | delay since last SR (DLSR) |
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
*/
let ssrc = raw_packet.get_u32();
let fraction_lost = raw_packet.get_u8();
let t0 = raw_packet.get_u8();
let t1 = raw_packet.get_u8();
let t2 = raw_packet.get_u8();
let total_lost = (t2 as u32) | (t1 as u32) << 8 | (t0 as u32) << 16;
let last_sequence_number = raw_packet.get_u32();
let jitter = raw_packet.get_u32();
let last_sender_report = raw_packet.get_u32();
let delay = raw_packet.get_u32();
Ok(ReceptionReport {
ssrc,
fraction_lost,
total_lost,
last_sequence_number,
jitter,
last_sender_report,
delay,
})
}
}