lint: fix warnings

Makefile

@@ -26,7 +26,7 @@ lint:
 		--vendor \
 		-e "_test.go.+(gocyclo|errcheck|dupl)" \
 		-e "attributes\.go.+credentials,.+,LOW.+\(gas\)" \
-		-e "parameter v always receives 8" \
+		-e "parameter v always receives 4" \
 		-e "function \(\*Client\).allocate\(\) is high .+\(gocyclo\)" \
 		--enable="lll" --line-length=100 \
 		--enable="gofmt" \

chandata.go

@@ -69,12 +69,6 @@ func (c *ChannelData) Encode() {
 	}
 }
 
-// STUN aligns attributes on 32-bit boundaries, attributes whose content
-// is not a multiple of 4 bytes are padded with 1, 2, or 3 bytes of
-// padding so that its value contains a multiple of 4 bytes.  The
-// padding bits are ignored, and may be any value.
-//
-// https://tools.ietf.org/html/rfc5389#section-15
 const padding = 4
 
 func nearestPaddedValueLength(l int) int {
@@ -87,15 +81,15 @@ func nearestPaddedValueLength(l int) int {
 
 // WriteHeader writes channel number and length.
 func (c *ChannelData) WriteHeader() {
-	if len(c.Raw) < 4 {
+	if len(c.Raw) < channelDataHeaderSize {
 		// Making WriteHeader call valid even when c.Raw
 		// is nil or len(c.Raw) is less than needed for header.
-		c.grow(4)
+		c.grow(channelDataHeaderSize)
 	}
 	// Early bounds check to guarantee safety of writes below.
 	_ = c.Raw[:channelDataHeaderSize]
-	bin.PutUint16(c.Raw[:2], uint16(c.Number))
-	bin.PutUint16(c.Raw[2:4],
+	bin.PutUint16(c.Raw[:channelDataNumberSize], uint16(c.Number))
+	bin.PutUint16(c.Raw[channelDataNumberSize:channelDataHeaderSize],
 		uint16(len(c.Data)),
 	)
 }
@@ -110,7 +104,7 @@ func (c *ChannelData) Decode() error {
 	if len(buf) < channelDataHeaderSize {
 		return io.ErrUnexpectedEOF
 	}
-	num := bin.Uint16(buf[0:channelDataNumberSize])
+	num := bin.Uint16(buf[:channelDataNumberSize])
 	c.Number = ChannelNumber(num)
 	l := bin.Uint16(buf[channelDataNumberSize:channelDataHeaderSize])
 	c.Data = buf[channelDataHeaderSize:]

chandata_test.go

@@ -263,6 +263,20 @@ func TestChromeChannelData(t *testing.T) {
 		if err := m.Decode(); err != nil {
 			t.Errorf("Packet %d: %v", i, err)
 		}
+		encoded := &ChannelData{
+			Data:   m.Data,
+			Number: m.Number,
+		}
+		encoded.Encode()
+		decoded := new(ChannelData)
+		decoded.Raw = encoded.Raw
+		if err := decoded.Decode(); err != nil {
+			t.Error(err)
+		}
+		if !decoded.Equal(m) {
+			t.Error("should be equal")
+		}
+
 		messages = append(messages, m)
 	}
 	if len(messages) != 2 {