1 files changed, 67 insertions, 0 deletions
diff --git a/vendor/github.com/pion/turn/v2/internal/proto/chann.go b/vendor/github.com/pion/turn/v2/internal/proto/chann.go
new file mode 100644
index 0000000..d64ef73
--- /dev/null
+++ b/vendor/github.com/pion/turn/v2/internal/proto/chann.go
@@ -0,0 +1,67 @@
+package proto
+
+import (
+	"encoding/binary"
+	"errors"
+	"strconv"
+
+	"github.com/pion/stun"
+)
+
+// ChannelNumber represents CHANNEL-NUMBER attribute.
+//
+// The CHANNEL-NUMBER attribute contains the number of the channel.
+//
+// RFC 5766 Section 14.1
+type ChannelNumber uint16 // encoded as uint16
+
+func (n ChannelNumber) String() string { return strconv.Itoa(int(n)) }
+
+// 16 bits of uint + 16 bits of RFFU = 0.
+const channelNumberSize = 4
+
+// AddTo adds CHANNEL-NUMBER to message.
+func (n ChannelNumber) AddTo(m *stun.Message) error {
+	v := make([]byte, channelNumberSize)
+	binary.BigEndian.PutUint16(v[:2], uint16(n))
+	// v[2:4] are zeroes (RFFU = 0)
+	m.Add(stun.AttrChannelNumber, v)
+	return nil
+}
+
+// GetFrom decodes CHANNEL-NUMBER from message.
+func (n *ChannelNumber) GetFrom(m *stun.Message) error {
+	v, err := m.Get(stun.AttrChannelNumber)
+	if err != nil {
+		return err
+	}
+	if err = stun.CheckSize(stun.AttrChannelNumber, len(v), channelNumberSize); err != nil {
+		return err
+	}
+	_ = v[channelNumberSize-1] // asserting length
+	*n = ChannelNumber(binary.BigEndian.Uint16(v[:2]))
+	// v[2:4] is RFFU and equals to 0.
+	return nil
+}
+
+// See https://tools.ietf.org/html/rfc5766#section-11:
+//
+// 0x4000 through 0x7FFF: These values are the allowed channel
+// numbers (16,383 possible values).
+const (
+	MinChannelNumber = 0x4000
+	MaxChannelNumber = 0x7FFF
+)
+
+// ErrInvalidChannelNumber means that channel number is not valid as by RFC 5766 Section 11.
+var ErrInvalidChannelNumber = errors.New("channel number not in [0x4000, 0x7FFF]")
+
+// isChannelNumberValid returns true if c in [0x4000, 0x7FFF].
+func isChannelNumberValid(c uint16) bool {
+	return c >= MinChannelNumber && c <= MaxChannelNumber
+}
+
+// Valid returns true if channel number has correct value that complies RFC 5766 Section 11 range.
+func (n ChannelNumber) Valid() bool {
+	return isChannelNumberValid(uint16(n))
+}