1 files changed, 145 insertions, 0 deletions
diff --git a/vendor/github.com/pion/sctp/chunk_forward_tsn.go b/vendor/github.com/pion/sctp/chunk_forward_tsn.go
new file mode 100644
index 0000000..f6ff357
--- /dev/null
+++ b/vendor/github.com/pion/sctp/chunk_forward_tsn.go
@@ -0,0 +1,145 @@
+package sctp
+
+import (
+	"encoding/binary"
+	"fmt"
+
+	"github.com/pkg/errors"
+)
+
+// This chunk shall be used by the data sender to inform the data
+// receiver to adjust its cumulative received TSN point forward because
+// some missing TSNs are associated with data chunks that SHOULD NOT be
+// transmitted or retransmitted by the sender.
+//
+//  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
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |   Type = 192  |  Flags = 0x00 |        Length = Variable      |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |                      New Cumulative TSN                       |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |         Stream-1              |       Stream Sequence-1       |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// \                                                               /
+// /                                                               \
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |         Stream-N              |       Stream Sequence-N       |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+type chunkForwardTSN struct {
+	chunkHeader
+
+	// This indicates the new cumulative TSN to the data receiver.  Upon
+	// the reception of this value, the data receiver MUST consider
+	// any missing TSNs earlier than or equal to this value as received,
+	// and stop reporting them as gaps in any subsequent SACKs.
+	newCumulativeTSN uint32
+
+	streams []chunkForwardTSNStream
+}
+
+const (
+	newCumulativeTSNLength = 4
+	forwardTSNStreamLength = 4
+)
+
+var errMarshalStreamFailed = errors.New("failed to marshal stream")
+
+func (c *chunkForwardTSN) unmarshal(raw []byte) error {
+	if err := c.chunkHeader.unmarshal(raw); err != nil {
+		return err
+	}
+
+	if len(c.raw) < newCumulativeTSNLength {
+		return errors.New("chunk to short")
+	}
+
+	c.newCumulativeTSN = binary.BigEndian.Uint32(c.raw[0:])
+
+	offset := newCumulativeTSNLength
+	remaining := len(c.raw) - offset
+	for remaining > 0 {
+		s := chunkForwardTSNStream{}
+
+		if err := s.unmarshal(c.raw[offset:]); err != nil {
+			return fmt.Errorf("failed to unmarshal stream: %w", err)
+		}
+
+		c.streams = append(c.streams, s)
+
+		offset += s.length()
+		remaining -= s.length()
+	}
+
+	return nil
+}
+
+func (c *chunkForwardTSN) marshal() ([]byte, error) {
+	out := make([]byte, newCumulativeTSNLength)
+	binary.BigEndian.PutUint32(out[0:], c.newCumulativeTSN)
+
+	for _, s := range c.streams {
+		b, err := s.marshal()
+		if err != nil {
+			return nil, fmt.Errorf("%w: %v", errMarshalStreamFailed, err)
+		}
+		out = append(out, b...)
+	}
+
+	c.typ = ctForwardTSN
+	c.raw = out
+	return c.chunkHeader.marshal()
+}
+
+func (c *chunkForwardTSN) check() (abort bool, err error) {
+	return true, nil
+}
+
+// String makes chunkForwardTSN printable
+func (c *chunkForwardTSN) String() string {
+	res := fmt.Sprintf("New Cumulative TSN: %d\n", c.newCumulativeTSN)
+	for _, s := range c.streams {
+		res += fmt.Sprintf(" - si=%d, ssn=%d\n", s.identifier, s.sequence)
+	}
+	return res
+}
+
+type chunkForwardTSNStream struct {
+	// This field holds a stream number that was skipped by this
+	// FWD-TSN.
+	identifier uint16
+
+	// This field holds the sequence number associated with the stream
+	// that was skipped.  The stream sequence field holds the largest
+	// stream sequence number in this stream being skipped.  The receiver
+	// of the FWD-TSN's can use the Stream-N and Stream Sequence-N fields
+	// to enable delivery of any stranded TSN's that remain on the stream
+	// re-ordering queues.  This field MUST NOT report TSN's corresponding
+	// to DATA chunks that are marked as unordered.  For ordered DATA
+	// chunks this field MUST be filled in.
+	sequence uint16
+}
+
+func (s *chunkForwardTSNStream) length() int {
+	return forwardTSNStreamLength
+}
+
+func (s *chunkForwardTSNStream) unmarshal(raw []byte) error {
+	if len(raw) < forwardTSNStreamLength {
+		return errors.New("stream to short")
+	}
+	s.identifier = binary.BigEndian.Uint16(raw[0:])
+	s.sequence = binary.BigEndian.Uint16(raw[2:])
+
+	return nil
+}
+
+func (s *chunkForwardTSNStream) marshal() ([]byte, error) { // nolint:unparam
+	out := make([]byte, forwardTSNStreamLength)
+
+	binary.BigEndian.PutUint16(out[0:], s.identifier)
+	binary.BigEndian.PutUint16(out[2:], s.sequence)
+
+	return out, nil
+}