Fix lint errors

Makefile

 ROOT_DIR     := $(shell dirname $(realpath $(lastword $(MAKEFILE_LIST))))
 IMAGE_NAME   := mtg
 APP_NAME     := $(IMAGE_NAME)
-GOMETALINTER := gometalinter.v2
+GOMETALINTER := gometalinter
 
 VENDOR_FILES := $(shell find "$(ROOT_DIR)/vendor" 2>/dev/null || echo -n "vendor")
 CC_BINARIES  := $(shell bash -c "echo -n $(APP_NAME)-{linux,windows,darwin,freebsd,openbsd}-{386,amd64} $(APP_NAME)-linux-{arm,arm64}")

config/config.go

 	"github.com/juju/errors"
 )
 
+// Config represents common configuration of mtg.
 type Config struct {
-	Debug    bool
-	Verbose  bool
-	BindIP   net.IP
-	BindPort uint16
+	Debug   bool
+	Verbose bool
 
-	PublicIPv4     net.IP
+	BindPort       uint16
 	PublicIPv4Port uint16
-	PublicIPv6     net.IP
 	PublicIPv6Port uint16
-
-	StatsIP   net.IP
-	StatsPort uint16
+	StatsPort      uint16
 
 	TimeoutRead  time.Duration
 	TimeoutWrite time.Duration
 
+	BindIP     net.IP
+	PublicIPv4 net.IP
+	PublicIPv6 net.IP
+	StatsIP    net.IP
+
 	Secret []byte
 }
 
+// URLs contains links to the proxy (tg://, t.me) and their QR codes.
 type URLs struct {
 	TG        string `json:"tg_url"`
 	TMe       string `json:"tme_url"`
 	TMeQRCode string `json:"tme_qrcode"`
 }
 
+// IPURLs contains links to both ipv4 and ipv6 of the proxy.
 type IPURLs struct {
 	IPv4 URLs `json:"ipv4"`
 	IPv6 URLs `json:"ipv6"`
 }
 
+// BindAddr returns connection for this server to bind to.
 func (c *Config) BindAddr() string {
 	return getAddr(c.BindIP, c.BindPort)
 }
 
+// IPv4Addr returns connection string to ipv6 for mtproto proxy.
 func (c *Config) IPv4Addr() string {
 	return getAddr(c.PublicIPv4, c.PublicIPv4Port)
 }
 
+// IPv6Addr returns connection string to ipv6 for mtproto proxy.
 func (c *Config) IPv6Addr() string {
 	return getAddr(c.PublicIPv6, c.PublicIPv6Port)
 }
 
+// StatAddr returns connection string to the stats API.
 func (c *Config) StatAddr() string {
 	return getAddr(c.StatsIP, c.StatsPort)
 }
 
+// GetURLs returns configured IPURLs instance with links to this server.
 func (c *Config) GetURLs() IPURLs {
 	return IPURLs{
 		IPv4: getURLs(c.PublicIPv4, c.PublicIPv4Port, c.Secret),
 	return net.JoinHostPort(host.String(), strconv.Itoa(int(port)))
 }
 
-func NewConfig(debug, verbose bool,
+// NewConfig returns new configuration. If required, it manages and
+// fetches data from external sources. Parameters passed to this
+// function, should come from command line arguments.
+func NewConfig(debug, verbose bool, // nolint: gocyclo
 	bindIP net.IP, bindPort uint16,
 	publicIPv4 net.IP, PublicIPv4Port uint16,
 	publicIPv6 net.IP, publicIPv6Port uint16,
 		PublicIPv4Port: PublicIPv4Port,
 		PublicIPv6:     publicIPv6,
 		PublicIPv6Port: publicIPv6Port,
+		StatsIP:        statsIP,
+		StatsPort:      statsPort,
 		TimeoutRead:    timeoutRead,
 		TimeoutWrite:   timeoutWrite,
 		Secret:         secretBytes,

config/global_ips.go

 	if err != nil {
 		return nil, err
 	}
-	defer resp.Body.Close()
+	defer resp.Body.Close() // nolint: errcheck
 
 	respData, err := ioutil.ReadAll(resp.Body)
 	if err != nil {

config/urls.go

 	values.Set("secret", hex.EncodeToString(secret))
 
 	urls.TG = makeTGURL(values)
-	urls.TMe = makeTGURL(values)
+	urls.TMe = makeTMeURL(values)
 	urls.TGQRCode = makeQRCodeURL(urls.TG)
 	urls.TMeQRCode = makeQRCodeURL(urls.TG)
 

obfuscated2/obfuscated2_test.go

 	data := []byte{1, 2, 3}
 	encrypted := make([]byte, 3)
 	encryptor.XORKeyStream(encrypted, data)
-	decrypted := obfs2.Decrypt(encrypted)
+	decrypted := make([]byte, 3)
+	obfs2.Decryptor.XORKeyStream(decrypted, encrypted)
 
 	assert.Equal(t, data, decrypted)
 }
 	tgEncryptedMessage := make([]byte, len(message))
 	tgEncryptor.XORKeyStream(tgEncryptedMessage, message)
 
-	tgEncDecryptedMessage := tgObfs.Decrypt(tgEncryptedMessage)
+	tgEncDecryptedMessage := make([]byte, len(tgEncryptedMessage))
+	tgObfs.Decryptor.XORKeyStream(tgEncDecryptedMessage, tgEncryptedMessage)
 	assert.Equal(t, message, tgEncDecryptedMessage)
 
-	clientEncryptedMessage := clientObfs.Encrypt(tgEncDecryptedMessage)
+	clientEncryptedMessage := make([]byte, len(tgEncDecryptedMessage))
+	clientObfs.Encryptor.XORKeyStream(clientEncryptedMessage, tgEncDecryptedMessage)
 	finalMessage := make([]byte, len(clientEncryptedMessage))
 	clientDecryptor.XORKeyStream(finalMessage, clientEncryptedMessage)