diff options
Diffstat (limited to 'vendor/github.com/pion/rtcp/source_description.go')
| -rw-r--r-- | vendor/github.com/pion/rtcp/source_description.go | 352 |
1 files changed, 352 insertions, 0 deletions
diff --git a/vendor/github.com/pion/rtcp/source_description.go b/vendor/github.com/pion/rtcp/source_description.go new file mode 100644 index 0000000..4306b66 --- /dev/null +++ b/vendor/github.com/pion/rtcp/source_description.go @@ -0,0 +1,352 @@ +package rtcp + +import ( + "encoding/binary" + "fmt" +) + +// SDESType is the item type used in the RTCP SDES control packet. +type SDESType uint8 + +// RTP SDES item types registered with IANA. See: https://www.iana.org/assignments/rtp-parameters/rtp-parameters.xhtml#rtp-parameters-5 +const ( + SDESEnd SDESType = iota // end of SDES list RFC 3550, 6.5 + SDESCNAME // canonical name RFC 3550, 6.5.1 + SDESName // user name RFC 3550, 6.5.2 + SDESEmail // user's electronic mail address RFC 3550, 6.5.3 + SDESPhone // user's phone number RFC 3550, 6.5.4 + SDESLocation // geographic user location RFC 3550, 6.5.5 + SDESTool // name of application or tool RFC 3550, 6.5.6 + SDESNote // notice about the source RFC 3550, 6.5.7 + SDESPrivate // private extensions RFC 3550, 6.5.8 (not implemented) +) + +func (s SDESType) String() string { + switch s { + case SDESEnd: + return "END" + case SDESCNAME: + return "CNAME" + case SDESName: + return "NAME" + case SDESEmail: + return "EMAIL" + case SDESPhone: + return "PHONE" + case SDESLocation: + return "LOC" + case SDESTool: + return "TOOL" + case SDESNote: + return "NOTE" + case SDESPrivate: + return "PRIV" + default: + return string(s) + } +} + +const ( + sdesSourceLen = 4 + sdesTypeLen = 1 + sdesTypeOffset = 0 + sdesOctetCountLen = 1 + sdesOctetCountOffset = 1 + sdesMaxOctetCount = (1 << 8) - 1 + sdesTextOffset = 2 +) + +// A SourceDescription (SDES) packet describes the sources in an RTP stream. +type SourceDescription struct { + Chunks []SourceDescriptionChunk +} + +var _ Packet = (*SourceDescription)(nil) // assert is a Packet + +// Marshal encodes the SourceDescription in binary +func (s SourceDescription) 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| SC | PT=SDES=202 | length | + * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ + * chunk | SSRC/CSRC_1 | + * 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | SDES items | + * | ... | + * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ + * chunk | SSRC/CSRC_2 | + * 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | SDES items | + * | ... | + * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ + */ + + rawPacket := make([]byte, s.len()) + packetBody := rawPacket[headerLength:] + + chunkOffset := 0 + for _, c := range s.Chunks { + data, err := c.Marshal() + if err != nil { + return nil, err + } + copy(packetBody[chunkOffset:], data) + chunkOffset += len(data) + } + + if len(s.Chunks) > countMax { + return nil, errTooManyChunks + } + + hData, err := s.Header().Marshal() + if err != nil { + return nil, err + } + copy(rawPacket, hData) + + return rawPacket, nil +} + +// Unmarshal decodes the SourceDescription from binary +func (s *SourceDescription) 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| SC | PT=SDES=202 | length | + * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ + * chunk | SSRC/CSRC_1 | + * 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | SDES items | + * | ... | + * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ + * chunk | SSRC/CSRC_2 | + * 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | SDES items | + * | ... | + * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ + */ + + var h Header + if err := h.Unmarshal(rawPacket); err != nil { + return err + } + + if h.Type != TypeSourceDescription { + return errWrongType + } + + for i := headerLength; i < len(rawPacket); { + var chunk SourceDescriptionChunk + if err := chunk.Unmarshal(rawPacket[i:]); err != nil { + return err + } + s.Chunks = append(s.Chunks, chunk) + + i += chunk.len() + } + + if len(s.Chunks) != int(h.Count) { + return errInvalidHeader + } + + return nil +} + +func (s *SourceDescription) len() int { + chunksLength := 0 + for _, c := range s.Chunks { + chunksLength += c.len() + } + return headerLength + chunksLength +} + +// Header returns the Header associated with this packet. +func (s *SourceDescription) Header() Header { + return Header{ + Count: uint8(len(s.Chunks)), + Type: TypeSourceDescription, + Length: uint16((s.len() / 4) - 1), + } +} + +// A SourceDescriptionChunk contains items describing a single RTP source +type SourceDescriptionChunk struct { + // The source (ssrc) or contributing source (csrc) identifier this packet describes + Source uint32 + Items []SourceDescriptionItem +} + +// Marshal encodes the SourceDescriptionChunk in binary +func (s SourceDescriptionChunk) Marshal() ([]byte, error) { + /* + * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ + * | SSRC/CSRC_1 | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | SDES items | + * | ... | + * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ + */ + + rawPacket := make([]byte, sdesSourceLen) + binary.BigEndian.PutUint32(rawPacket, s.Source) + + for _, it := range s.Items { + data, err := it.Marshal() + if err != nil { + return nil, err + } + rawPacket = append(rawPacket, data...) + } + + // The list of items in each chunk MUST be terminated by one or more null octets + rawPacket = append(rawPacket, uint8(SDESEnd)) + + // additional null octets MUST be included if needed to pad until the next 32-bit boundary + rawPacket = append(rawPacket, make([]byte, getPadding(len(rawPacket)))...) + + return rawPacket, nil +} + +// Unmarshal decodes the SourceDescriptionChunk from binary +func (s *SourceDescriptionChunk) Unmarshal(rawPacket []byte) error { + /* + * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ + * | SSRC/CSRC_1 | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | SDES items | + * | ... | + * +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ + */ + + if len(rawPacket) < (sdesSourceLen + sdesTypeLen) { + return errPacketTooShort + } + + s.Source = binary.BigEndian.Uint32(rawPacket) + + for i := 4; i < len(rawPacket); { + if pktType := SDESType(rawPacket[i]); pktType == SDESEnd { + return nil + } + + var it SourceDescriptionItem + if err := it.Unmarshal(rawPacket[i:]); err != nil { + return err + } + s.Items = append(s.Items, it) + i += it.len() + } + + return errPacketTooShort +} + +func (s SourceDescriptionChunk) len() int { + len := sdesSourceLen + for _, it := range s.Items { + len += it.len() + } + len += sdesTypeLen // for terminating null octet + + // align to 32-bit boundary + len += getPadding(len) + + return len +} + +// A SourceDescriptionItem is a part of a SourceDescription that describes a stream. +type SourceDescriptionItem struct { + // The type identifier for this item. eg, SDESCNAME for canonical name description. + // + // Type zero or SDESEnd is interpreted as the end of an item list and cannot be used. + Type SDESType + // Text is a unicode text blob associated with the item. Its meaning varies based on the item's Type. + Text string +} + +func (s SourceDescriptionItem) len() int { + /* + * 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 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | CNAME=1 | length | user and domain name ... + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + */ + return sdesTypeLen + sdesOctetCountLen + len([]byte(s.Text)) +} + +// Marshal encodes the SourceDescriptionItem in binary +func (s SourceDescriptionItem) 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 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | CNAME=1 | length | user and domain name ... + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + */ + + if s.Type == SDESEnd { + return nil, errSDESMissingType + } + + rawPacket := make([]byte, sdesTypeLen+sdesOctetCountLen) + + rawPacket[sdesTypeOffset] = uint8(s.Type) + + txtBytes := []byte(s.Text) + octetCount := len(txtBytes) + if octetCount > sdesMaxOctetCount { + return nil, errSDESTextTooLong + } + rawPacket[sdesOctetCountOffset] = uint8(octetCount) + + rawPacket = append(rawPacket, txtBytes...) + + return rawPacket, nil +} + +// Unmarshal decodes the SourceDescriptionItem from binary +func (s *SourceDescriptionItem) 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 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | CNAME=1 | length | user and domain name ... + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + */ + + if len(rawPacket) < (sdesTypeLen + sdesOctetCountLen) { + return errPacketTooShort + } + + s.Type = SDESType(rawPacket[sdesTypeOffset]) + + octetCount := int(rawPacket[sdesOctetCountOffset]) + if sdesTextOffset+octetCount > len(rawPacket) { + return errPacketTooShort + } + + txtBytes := rawPacket[sdesTextOffset : sdesTextOffset+octetCount] + s.Text = string(txtBytes) + + return nil +} + +// DestinationSSRC returns an array of SSRC values that this packet refers to. +func (s *SourceDescription) DestinationSSRC() []uint32 { + out := make([]uint32, len(s.Chunks)) + for i, v := range s.Chunks { + out[i] = v.Source + } + return out +} + +func (s *SourceDescription) String() string { + out := "Source Description:\n" + for _, c := range s.Chunks { + out += fmt.Sprintf("\t%x: %s\n", c.Source, c.Items) + } + return out +} |