Reassemble partial packets on the client

The sender's network stack assembles tcp packets without regard for
write boundaries, so the receiver has to be prepared for partial reads.

tcpdelay.go

@@ -2,8 +2,8 @@ package main
 
 import (
 	"encoding/binary"
-	"gopkg.in/alecthomas/kingpin.v2"
 	"fmt"
+	"gopkg.in/alecthomas/kingpin.v2"
 	"log"
 	"net"
 	"os"
@@ -16,7 +16,7 @@ var (
 	server        = app.Command("server", "Run as server")
 	listenAddress = server.Arg("address", "Address:port to listen on").String()
 
-	client = app.Command("client", "Request measurement")
+	client        = app.Command("client", "Request measurement")
 	serverAddress = client.Arg("address", "Address:port to connect to").String()
 )
 
@@ -63,12 +63,16 @@ func tcpdelayClient() {
 	o := 0
 	buffer := make([]byte, 1024)
 	for {
-		n, err := conn.Read(buffer)
+		n := 0
-		if err != nil {
+		for n < len(buffer) {
-			log.Fatal("Cannot read from ", *serverAddress, err)
+			nr, err := conn.Read(buffer[n:])
-		}
+			if err != nil {
-		if n != len(buffer) {
+				log.Fatal("Cannot read from ", *serverAddress, err.Error())
-			log.Fatal("Read ", n, " bytes intead of ", len(buffer))
+			}
+			if nr <= 0 {
+				log.Fatal("Read ", n, " bytes intead of ", len(buffer))
+			}
+			n += nr
 		}
 		tr := time.Now().UnixNano()
 		if string(buffer[0:8]) != "tcpdelay" {