From 1de50450031878c1f2ae6e54f493e9f742028ff1 Mon Sep 17 00:00:00 2001
From: Andy Wang <cbeuw.andy@gmail.com>
Date: Wed, 8 Apr 2020 14:59:09 +0100
Subject: [PATCH] Use errors from io

---
 internal/multiplex/datagramBuffer.go | 3 +--
 internal/multiplex/obfs.go           | 3 ++-
 internal/multiplex/recvBuffer.go     | 1 +
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/internal/multiplex/datagramBuffer.go b/internal/multiplex/datagramBuffer.go
index eebbf48..7232061 100644
--- a/internal/multiplex/datagramBuffer.go
+++ b/internal/multiplex/datagramBuffer.go
@@ -3,7 +3,6 @@
 package multiplex
 
 import (
-	"errors"
 	"io"
 	"sync"
 	"sync/atomic"
@@ -43,7 +42,7 @@ func (d *datagramBuffer) Read(target []byte) (int, error) {
 	}
 	data := d.buf[0]
 	if len(target) < len(data) {
-		return 0, errors.New("buffer is too small")
+		return 0, io.ErrShortBuffer
 	}
 	d.buf = d.buf[1:]
 	copy(target, data)
diff --git a/internal/multiplex/obfs.go b/internal/multiplex/obfs.go
index dd60acc..edaf381 100644
--- a/internal/multiplex/obfs.go
+++ b/internal/multiplex/obfs.go
@@ -9,6 +9,7 @@ import (
 	"github.com/cbeuw/Cloak/internal/util"
 	"golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/crypto/salsa20"
+	"io"
 )
 
 type Obfser func(*Frame, []byte) (int, error)
@@ -57,7 +58,7 @@ func MakeObfs(salsaKey [32]byte, payloadCipher cipher.AEAD, hasRecordLayer bool)
 		// usefulLen is the amount of bytes that will be eventually sent off
 		usefulLen := rlLen + HEADER_LEN + len(f.Payload) + int(extraLen)
 		if len(buf) < usefulLen {
-			return 0, errors.New("buffer is too small")
+			return 0, io.ErrShortBuffer
 
 		}
 		// we do as much in-place as possible to save allocation
diff --git a/internal/multiplex/recvBuffer.go b/internal/multiplex/recvBuffer.go
index db5c844..babc274 100644
--- a/internal/multiplex/recvBuffer.go
+++ b/internal/multiplex/recvBuffer.go
@@ -3,6 +3,7 @@ package multiplex
 import "io"
 
 type recvBuffer interface {
+	// Read calls' err must be nil | io.EOF | io.ErrShortBuffer
 	io.ReadCloser
 	Write(Frame) (toBeClosed bool, err error)
 }