From 56843b1f9ff3f4fd67a244ddcc0098f575eee8e2 Mon Sep 17 00:00:00 2001
From: Simon Whitehead <chemnova@gmail.com>
Date: Thu, 6 Nov 2014 08:28:54 +1100
Subject: [PATCH] Fixed payload size. Added tests.

---
 fastping.go      | 15 ++++++++-------
 fastping_test.go | 18 ++++++++++++++++++
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/fastping.go b/fastping.go
index 5ead15f..c7ca0c4 100644
--- a/fastping.go
+++ b/fastping.go
@@ -47,12 +47,9 @@ import (
 	"time"
 )
 
-const TimeSliceLengh = 8
+const TimeSliceLength = 8
 
 func byteSliceOfSize(n int) []byte {
-	if n == 0 {
-		n = TimeSliceLengh // if its 0 .. default it to 8
-	}
 	b := make([]byte, n)
 	for i := 0; i < len(b); i++ {
 		b[i] = 1
@@ -139,7 +136,7 @@ func NewPinger() *Pinger {
 		addrs:   make(map[string]*net.IPAddr),
 		hasIPv4: false,
 		hasIPv6: false,
-		Size:    TimeSliceLengh,
+		Size:    TimeSliceLength,
 		MaxRTT:  time.Second,
 		OnRecv:  nil,
 		OnIdle:  nil,
@@ -409,12 +406,16 @@ func (p *Pinger) sendICMP(conn, conn6 *net.IPConn) (map[string]*net.IPAddr, erro
 
 		t := timeToBytes(time.Now())
 
+		if p.Size-TimeSliceLength != 0 {
+			t = append(t, byteSliceOfSize(p.Size-TimeSliceLength)...)
+		}
+
 		p.mu.Lock()
 		bytes, err := (&icmpMessage{
 			Type: typ, Code: 0,
 			Body: &icmpEcho{
 				ID: p.id, Seq: p.seq,
-				Data: append(t, byteSliceOfSize(p.Size-TimeSliceLengh)...),
+				Data: t,
 			},
 		}).Marshal()
 		p.mu.Unlock()
@@ -520,7 +521,7 @@ func (p *Pinger) procRecv(recv *packet, queue map[string]*net.IPAddr) {
 	case *icmpEcho:
 		p.mu.Lock()
 		if pkt.ID == p.id && pkt.Seq == p.seq {
-			rtt = time.Since(bytesToTime(pkt.Data[:TimeSliceLengh]))
+			rtt = time.Since(bytesToTime(pkt.Data[:TimeSliceLength]))
 		}
 		p.mu.Unlock()
 	default:
diff --git a/fastping_test.go b/fastping_test.go
index fc5d683..cef5ab9 100644
--- a/fastping_test.go
+++ b/fastping_test.go
@@ -252,3 +252,21 @@ func TestTimeToBytesToTime(t *testing.T) {
 		t.Errorf("bytesToTime failed: got %v, expected: %v", tm2.UTC(), tm.UTC())
 	}
 }
+
+func TestPayloadSizeDefault(t *testing.T) {
+	s := timeToBytes(time.Now())
+	d := append(s, byteSliceOfSize(8-TimeSliceLength)...)
+
+	if len(d) != 8 {
+		t.Errorf("Payload size incorrect: got %d, expected: %d", len(d), 8)
+	}
+}
+
+func TestPayloadSizeCustom(t *testing.T) {
+	s := timeToBytes(time.Now())
+	d := append(s, byteSliceOfSize(64-TimeSliceLength)...)
+
+	if len(d) != 64 {
+		t.Errorf("Payload size incorrect: got %d, expected: %d", len(d), 64)
+	}
+}