1 use crate::{error::Error, header::*, packet::*, util::*}; 2 use util::marshal::{Marshal, MarshalSize, Unmarshal}; 3 4 use bytes::{Buf, BufMut}; 5 use std::any::Any; 6 use std::fmt; 7 8 pub(crate) const RECEPTION_REPORT_LENGTH: usize = 24; 9 pub(crate) const FRACTION_LOST_OFFSET: usize = 4; 10 pub(crate) const TOTAL_LOST_OFFSET: usize = 5; 11 pub(crate) const LAST_SEQ_OFFSET: usize = 8; 12 pub(crate) const JITTER_OFFSET: usize = 12; 13 pub(crate) const LAST_SR_OFFSET: usize = 16; 14 pub(crate) const DELAY_OFFSET: usize = 20; 15 16 /// A ReceptionReport block conveys statistics on the reception of RTP packets 17 /// from a single synchronization source. 18 #[derive(Debug, PartialEq, Eq, Default, Clone)] 19 pub struct ReceptionReport { 20 /// The SSRC identifier of the source to which the information in this 21 /// reception report block pertains. 22 pub ssrc: u32, 23 /// The fraction of RTP data packets from source SSRC lost since the 24 /// previous SR or RR packet was sent, expressed as a fixed point 25 /// number with the binary point at the left edge of the field. 26 pub fraction_lost: u8, 27 /// The total number of RTP data packets from source SSRC that have 28 /// been lost since the beginning of reception. 29 pub total_lost: u32, 30 /// The low 16 bits contain the highest sequence number received in an 31 /// RTP data packet from source SSRC, and the most significant 16 32 /// bits extend that sequence number with the corresponding count of 33 /// sequence number cycles. 34 pub last_sequence_number: u32, 35 /// An estimate of the statistical variance of the RTP data packet 36 /// interarrival time, measured in timestamp units and expressed as an 37 /// unsigned integer. 38 pub jitter: u32, 39 /// The middle 32 bits out of 64 in the NTP timestamp received as part of 40 /// the most recent RTCP sender report (SR) packet from source SSRC. If no 41 /// SR has been received yet, the field is set to zero. 42 pub last_sender_report: u32, 43 /// The delay, expressed in units of 1/65536 seconds, between receiving the 44 /// last SR packet from source SSRC and sending this reception report block. 45 /// If no SR packet has been received yet from SSRC, the field is set to zero. 46 pub delay: u32, 47 } 48 49 impl fmt::Display for ReceptionReport { 50 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { 51 write!(f, "{:?}", self) 52 } 53 } 54 55 impl Packet for ReceptionReport { 56 fn header(&self) -> Header { 57 Header::default() 58 } 59 60 fn destination_ssrc(&self) -> Vec<u32> { 61 vec![] 62 } 63 64 fn raw_size(&self) -> usize { 65 RECEPTION_REPORT_LENGTH 66 } 67 68 fn as_any(&self) -> &(dyn Any + Send + Sync) { 69 self 70 } 71 72 fn equal(&self, other: &(dyn Packet + Send + Sync)) -> bool { 73 other 74 .as_any() 75 .downcast_ref::<ReceptionReport>() 76 .map_or(false, |a| self == a) 77 } 78 79 fn cloned(&self) -> Box<dyn Packet + Send + Sync> { 80 Box::new(self.clone()) 81 } 82 } 83 84 impl MarshalSize for ReceptionReport { 85 fn marshal_size(&self) -> usize { 86 let l = self.raw_size(); 87 // align to 32-bit boundary 88 l + get_padding_size(l) 89 } 90 } 91 92 impl Marshal for ReceptionReport { 93 /// marshal_to encodes the ReceptionReport in binary 94 fn marshal_to(&self, mut buf: &mut [u8]) -> Result<usize, util::Error> { 95 /* 96 * 0 1 2 3 97 * 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 98 * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ 99 * | SSRC | 100 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 101 * | fraction lost | cumulative number of packets lost | 102 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 103 * | extended highest sequence number received | 104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 105 * | interarrival jitter | 106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 107 * | last SR (LSR) | 108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 109 * | delay since last SR (DLSR) | 110 * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ 111 */ 112 if buf.remaining_mut() < self.marshal_size() { 113 return Err(Error::BufferTooShort.into()); 114 } 115 116 buf.put_u32(self.ssrc); 117 118 buf.put_u8(self.fraction_lost); 119 120 // pack TotalLost into 24 bits 121 if self.total_lost >= (1 << 25) { 122 return Err(Error::InvalidTotalLost.into()); 123 } 124 125 buf.put_u8(((self.total_lost >> 16) & 0xFF) as u8); 126 buf.put_u8(((self.total_lost >> 8) & 0xFF) as u8); 127 buf.put_u8((self.total_lost & 0xFF) as u8); 128 129 buf.put_u32(self.last_sequence_number); 130 buf.put_u32(self.jitter); 131 buf.put_u32(self.last_sender_report); 132 buf.put_u32(self.delay); 133 134 put_padding(buf, self.raw_size()); 135 136 Ok(self.marshal_size()) 137 } 138 } 139 140 impl Unmarshal for ReceptionReport { 141 /// unmarshal decodes the ReceptionReport from binary 142 fn unmarshal<B>(raw_packet: &mut B) -> Result<Self, util::Error> 143 where 144 Self: Sized, 145 B: Buf, 146 { 147 let raw_packet_len = raw_packet.remaining(); 148 if raw_packet_len < RECEPTION_REPORT_LENGTH { 149 return Err(Error::PacketTooShort.into()); 150 } 151 152 /* 153 * 0 1 2 3 154 * 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 1 155 * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ 156 * | SSRC | 157 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 * | fraction lost | cumulative number of packets lost | 159 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 160 * | extended highest sequence number received | 161 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 162 * | interarrival jitter | 163 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 164 * | last SR (LSR) | 165 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 166 * | delay since last SR (DLSR) | 167 * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ 168 */ 169 let ssrc = raw_packet.get_u32(); 170 let fraction_lost = raw_packet.get_u8(); 171 172 let t0 = raw_packet.get_u8(); 173 let t1 = raw_packet.get_u8(); 174 let t2 = raw_packet.get_u8(); 175 // TODO: The type of `total_lost` should be `i32`, per the RFC: 176 // The total number of RTP data packets from source SSRC_n that have 177 // been lost since the beginning of reception. This number is 178 // defined to be the number of packets expected less the number of 179 // packets actually received, where the number of packets received 180 // includes any which are late or duplicates. Thus, packets that 181 // arrive late are not counted as lost, and the loss may be negative 182 // if there are duplicates. The number of packets expected is 183 // defined to be the extended last sequence number received, as 184 // defined next, less the initial sequence number received. This may 185 // be calculated as shown in Appendix A.3. 186 let total_lost = (t2 as u32) | (t1 as u32) << 8 | (t0 as u32) << 16; 187 188 let last_sequence_number = raw_packet.get_u32(); 189 let jitter = raw_packet.get_u32(); 190 let last_sender_report = raw_packet.get_u32(); 191 let delay = raw_packet.get_u32(); 192 193 Ok(ReceptionReport { 194 ssrc, 195 fraction_lost, 196 total_lost, 197 last_sequence_number, 198 jitter, 199 last_sender_report, 200 delay, 201 }) 202 } 203 } 204