all: fix linters warnings; update makefile

Makefile

@@ -11,7 +11,9 @@ fuzz-msg:
 fuzz-typ:
 	go-fuzz -bin=./stun-typ-fuzz.zip -workdir=examples/stun-typ
 lint:
-	@gometalinter -e "AttrType.+gocyclo" -e "_test.go.+(gocyclo|errcheck|dupl)" --disable=gotype
+	@gometalinter -e "AttrType.+gocyclo" \
+		-e "_test.go.+(gocyclo|errcheck|dupl)" \
+		--enable="lll" --line-length=80
 escape:
 	@echo "Not escapes, except autogenerated:"
 	@go build -gcflags '-m -l' 2>&1 \
@@ -27,3 +29,10 @@ bench-compare:
 	go test -bench . > bench.go-16
 	go-tip test -bench . > bench.go-tip
 	@benchcmp bench.go-16 bench.go-tip
+
+install:
+	go get -u sourcegraph.com/sqs/goreturns
+	go get -u github.com/alecthomas/gometalinter
+	gometalinter --install --update
+	go get -u github.com/cydev/go-fuzz/go-fuzz-build
+	go get -u github.com/dvyukov/go-fuzz/go-fuzz

attributes_test.go

@@ -145,7 +145,7 @@ func TestMessage_GetXORMappedAddressBad(t *testing.T) {
 	mRes := AcquireMessage()
 	defer ReleaseMessage(mRes)
 	binary.BigEndian.PutUint16(m.buf.B[20+4:20+4+2], 0x21)
-	if err := mRes.Get(m.buf.B); err != nil {
+	if err = mRes.Get(m.buf.B); err != nil {
 		t.Fatal(err)
 	}
 	_, _, err = m.GetXORMappedAddress()
@@ -169,7 +169,7 @@ func TestMessage_AddXORMappedAddress(t *testing.T) {
 
 	mRes := AcquireMessage()
 	defer ReleaseMessage(mRes)
-	if err := mRes.Get(m.buf.B); err != nil {
+	if err = mRes.Get(m.buf.B); err != nil {
 		t.Fatal(err)
 	}
 	ip, port, err := m.GetXORMappedAddress()

client_test.go

@@ -63,6 +63,10 @@ func TestClientSend(t *testing.T) {
 			timeout *= 2
 		}
 		n, err := conn.Read(recvBuf)
+		var (
+			ip   net.IP
+			port int
+		)
 		if err == nil {
 			mRec := AcquireMessage()
 			if err = mRec.Get(recvBuf[:n]); err != nil {
@@ -75,7 +79,7 @@ func TestClientSend(t *testing.T) {
 			}
 			v := mRec.getAttrValue(AttrXORMappedAddress)
 			log.Println(v)
-			ip, port, err := mRec.GetXORMappedAddress()
+			ip, port, err = mRec.GetXORMappedAddress()
 			if err != nil {
 				t.Error(err)
 			}

xor_test.go

@@ -1,8 +1,8 @@
 package stun
 
 import (
-	"testing"
 	"math/rand"
+	"testing"
 )
 
 func TestXORSafe(t *testing.T) {
@@ -83,7 +83,6 @@ func TestXORFallback(t *testing.T) {
 	}
 }
 
-
 func BenchmarkXOR(b *testing.B) {
 	rand.Seed(666)
 	a := make([]byte, 1024)