Fix all lint errors

obfuscated2/obfuscated2.go

@@ -8,35 +8,43 @@ import (
 	"github.com/juju/errors"
 )
 
+// Obfuscated2 contains AES CTR encryption and decryption streams
+// for telegram connection.
 type Obfuscated2 struct {
 	decryptor cipher.Stream
 	encryptor cipher.Stream
 }
 
+// Encrypt encrypts given data.
 func (o *Obfuscated2) Encrypt(data []byte) []byte {
 	buf := make([]byte, len(data))
 	o.encryptor.XORKeyStream(buf, data)
 	return buf
 }
 
+// Decrypt decrypts given data.
 func (o *Obfuscated2) Decrypt(data []byte) []byte {
 	buf := make([]byte, len(data))
 	o.decryptor.XORKeyStream(buf, data)
 	return buf
 }
 
+// ParseObfuscated2ClientFrame parses client frame. Please check this link for
+// details: http://telegra.ph/telegram-blocks-wtf-05-26
+//
+// Beware, link above is in russian.
 func ParseObfuscated2ClientFrame(secret, data []byte) (*Obfuscated2, int16, error) {
 	frame := Frame(data)
 
 	decHasher := sha256.New()
-	decHasher.Write(frame.Key())
-	decHasher.Write(secret)
+	decHasher.Write(frame.Key()) // nolint: errcheck
+	decHasher.Write(secret)      // nolint: errcheck
 	decryptor := makeStreamCipher(decHasher.Sum(nil), frame.IV())
 
 	invertedFrame := frame.Invert()
 	encHasher := sha256.New()
-	encHasher.Write(invertedFrame.Key())
-	encHasher.Write(secret)
+	encHasher.Write(invertedFrame.Key()) // nolint: errcheck
+	encHasher.Write(secret)              // nolint: errcheck
 	encryptor := makeStreamCipher(encHasher.Sum(nil), invertedFrame.IV())
 
 	decryptedFrame := make(Frame, FrameLen)
@@ -53,6 +61,9 @@ func ParseObfuscated2ClientFrame(secret, data []byte) (*Obfuscated2, int16, erro
 	return obfs, decryptedFrame.DC(), nil
 }
 
+// MakeTelegramObfuscated2Frame creates new handshake frame to send to
+// Telegram.
+// https://blog.susanka.eu/how-telegram-obfuscates-its-mtproto-traffic/
 func MakeTelegramObfuscated2Frame() (*Obfuscated2, Frame) {
 	frame := generateFrame()