1 files changed, 90 insertions, 0 deletions
diff --git a/vendor/github.com/pion/sctp/chunkheader.go b/vendor/github.com/pion/sctp/chunkheader.go
new file mode 100644
index 0000000..a4a78db
--- /dev/null
+++ b/vendor/github.com/pion/sctp/chunkheader.go
@@ -0,0 +1,90 @@
+package sctp
+
+import (
+	"encoding/binary"
+
+	"github.com/pkg/errors"
+)
+
+/*
+chunkHeader represents a SCTP Chunk header, defined in https://tools.ietf.org/html/rfc4960#section-3.2
+The figure below illustrates the field format for the chunks to be
+transmitted in the SCTP packet.  Each chunk is formatted with a Chunk
+Type field, a chunk-specific Flag field, a Chunk Length field, and a
+Value field.
+
+ 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
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|   Chunk Type  | Chunk  Flags  |        Chunk Length           |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                                                               |
+|                          Chunk Value                          |
+|                                                               |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+*/
+type chunkHeader struct {
+	typ   chunkType
+	flags byte
+	raw   []byte
+}
+
+const (
+	chunkHeaderSize = 4
+)
+
+func (c *chunkHeader) unmarshal(raw []byte) error {
+	if len(raw) < chunkHeaderSize {
+		return errors.Errorf("raw only %d bytes, %d is the minimum length for a SCTP chunk", len(raw), chunkHeaderSize)
+	}
+
+	c.typ = chunkType(raw[0])
+	c.flags = raw[1]
+	length := binary.BigEndian.Uint16(raw[2:])
+
+	// Length includes Chunk header
+	valueLength := int(length - chunkHeaderSize)
+	lengthAfterValue := len(raw) - (chunkHeaderSize + valueLength)
+
+	if lengthAfterValue < 0 {
+		return errors.Errorf("Not enough data left in SCTP packet to satisfy requested length remain %d req %d ", valueLength, len(raw)-chunkHeaderSize)
+	} else if lengthAfterValue < 4 {
+		// https://tools.ietf.org/html/rfc4960#section-3.2
+		// The Chunk Length field does not count any chunk padding.
+		// Chunks (including Type, Length, and Value fields) are padded out
+		// by the sender with all zero bytes to be a multiple of 4 bytes
+		// long.  This padding MUST NOT be more than 3 bytes in total.  The
+		// Chunk Length value does not include terminating padding of the
+		// chunk.  However, it does include padding of any variable-length
+		// parameter except the last parameter in the chunk.  The receiver
+		// MUST ignore the padding.
+		for i := lengthAfterValue; i > 0; i-- {
+			paddingOffset := chunkHeaderSize + valueLength + (i - 1)
+			if raw[paddingOffset] != 0 {
+				return errors.Errorf("Chunk padding is non-zero at offset %d ", paddingOffset)
+			}
+		}
+	}
+
+	c.raw = raw[chunkHeaderSize : chunkHeaderSize+valueLength]
+	return nil
+}
+
+func (c *chunkHeader) marshal() ([]byte, error) {
+	raw := make([]byte, 4+len(c.raw))
+
+	raw[0] = uint8(c.typ)
+	raw[1] = c.flags
+	binary.BigEndian.PutUint16(raw[2:], uint16(len(c.raw)+chunkHeaderSize))
+	copy(raw[4:], c.raw)
+	return raw, nil
+}
+
+func (c *chunkHeader) valueLength() int {
+	return len(c.raw)
+}
+
+// String makes chunkHeader printable
+func (c chunkHeader) String() string {
+	return c.typ.String()
+}