status-go/vendor/github.com/pion/rtcp/receiver_report.go

192 lines
7.2 KiB
Go

package rtcp
import (
"encoding/binary"
"fmt"
)
// A ReceiverReport (RR) packet provides reception quality feedback for an RTP stream
type ReceiverReport struct {
// The synchronization source identifier for the originator of this RR packet.
SSRC uint32
// Zero or more reception report blocks depending on the number of other
// sources heard by this sender since the last report. Each reception report
// block conveys statistics on the reception of RTP packets from a
// single synchronization source.
Reports []ReceptionReport
// Extension contains additional, payload-specific information that needs to
// be reported regularly about the receiver.
ProfileExtensions []byte
}
const (
ssrcLength = 4
rrSSRCOffset = headerLength
rrReportOffset = rrSSRCOffset + ssrcLength
)
// Marshal encodes the ReceiverReport in binary
func (r ReceiverReport) Marshal() ([]byte, error) {
/*
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* header |V=2|P| RC | PT=RR=201 | length |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | SSRC of packet sender |
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
* report | SSRC_1 (SSRC of first source) |
* block +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* 1 | fraction lost | cumulative number of packets lost |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | extended highest sequence number received |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | interarrival jitter |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | last SR (LSR) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | delay since last SR (DLSR) |
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
* report | SSRC_2 (SSRC of second source) |
* block +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* 2 : ... :
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
* | profile-specific extensions |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
rawPacket := make([]byte, r.len())
packetBody := rawPacket[headerLength:]
binary.BigEndian.PutUint32(packetBody, r.SSRC)
for i, rp := range r.Reports {
data, err := rp.Marshal()
if err != nil {
return nil, err
}
offset := ssrcLength + receptionReportLength*i
copy(packetBody[offset:], data)
}
if len(r.Reports) > countMax {
return nil, errTooManyReports
}
pe := make([]byte, len(r.ProfileExtensions))
copy(pe, r.ProfileExtensions)
// if the length of the profile extensions isn't devisible
// by 4, we need to pad the end.
for (len(pe) & 0x3) != 0 {
pe = append(pe, 0)
}
rawPacket = append(rawPacket, pe...)
hData, err := r.Header().Marshal()
if err != nil {
return nil, err
}
copy(rawPacket, hData)
return rawPacket, nil
}
// Unmarshal decodes the ReceiverReport from binary
func (r *ReceiverReport) Unmarshal(rawPacket []byte) error {
/*
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* header |V=2|P| RC | PT=RR=201 | length |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | SSRC of packet sender |
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
* report | SSRC_1 (SSRC of first source) |
* block +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* 1 | fraction lost | cumulative number of packets lost |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | extended highest sequence number received |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | interarrival jitter |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | last SR (LSR) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | delay since last SR (DLSR) |
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
* report | SSRC_2 (SSRC of second source) |
* block +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* 2 : ... :
* +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
* | profile-specific extensions |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
if len(rawPacket) < (headerLength + ssrcLength) {
return errPacketTooShort
}
var h Header
if err := h.Unmarshal(rawPacket); err != nil {
return err
}
if h.Type != TypeReceiverReport {
return errWrongType
}
r.SSRC = binary.BigEndian.Uint32(rawPacket[rrSSRCOffset:])
for i := rrReportOffset; i < len(rawPacket) && len(r.Reports) < int(h.Count); i += receptionReportLength {
var rr ReceptionReport
if err := rr.Unmarshal(rawPacket[i:]); err != nil {
return err
}
r.Reports = append(r.Reports, rr)
}
r.ProfileExtensions = rawPacket[rrReportOffset+(len(r.Reports)*receptionReportLength):]
if uint8(len(r.Reports)) != h.Count {
return errInvalidHeader
}
return nil
}
func (r *ReceiverReport) len() int {
repsLength := 0
for _, rep := range r.Reports {
repsLength += rep.len()
}
return headerLength + ssrcLength + repsLength
}
// Header returns the Header associated with this packet.
func (r *ReceiverReport) Header() Header {
return Header{
Count: uint8(len(r.Reports)),
Type: TypeReceiverReport,
Length: uint16((r.len()/4)-1) + uint16(getPadding(len(r.ProfileExtensions))),
}
}
// DestinationSSRC returns an array of SSRC values that this packet refers to.
func (r *ReceiverReport) DestinationSSRC() []uint32 {
out := make([]uint32, len(r.Reports))
for i, v := range r.Reports {
out[i] = v.SSRC
}
return out
}
func (r ReceiverReport) String() string {
out := fmt.Sprintf("ReceiverReport from %x\n", r.SSRC)
out += "\tSSRC \tLost\tLastSequence\n"
for _, i := range r.Reports {
out += fmt.Sprintf("\t%x\t%d/%d\t%d\n", i.SSRC, i.FractionLost, i.TotalLost, i.LastSequenceNumber)
}
out += fmt.Sprintf("\tProfile Extension Data: %v\n", r.ProfileExtensions)
return out
}