Add netcat

Initial netcat commit

Author: N2D4

Makefile

@@ -2,7 +2,7 @@
 
 ROOT_DIR=$(shell dirname $(realpath $(lastword $(MAKEFILE_LIST))))
 # TODO: missing roughtime/timeserver roughtime/timeclient
-SRCDIRS= helloworld sensorapp/sensorserver sensorapp/sensorfetcher camerapp/imageserver camerapp/imagefetcher bwtester/bwtestserver bwtester/bwtestclient webapp bat bat/example_server tools/pathdb_dump
+SRCDIRS= helloworld sensorapp/sensorserver sensorapp/sensorfetcher camerapp/imageserver camerapp/imagefetcher bwtester/bwtestserver bwtester/bwtestclient webapp bat bat/example_server tools/pathdb_dump netcat
 TARGETS = $(foreach D,$(SRCDIRS),$(D)/$(notdir $(D)))
 
 all: $(TARGETS)

netcat/README.md

@@ -0,0 +1,9 @@
+# scion-netcat
+A SCION port of the netcat process.
+
+
+## Usage
+```./netcat <host> <port>```
+
+See `./netcat -h` for more.
+

netcat/main.go

@@ -0,0 +1,182 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"io"
+	golog "log"
+	"os"
+	"strconv"
+	"sync"
+
+	quic "github.com/lucas-clemente/quic-go"
+	"github.com/netsec-ethz/scion-apps/lib/scionutil"
+	scionlog "github.com/scionproto/scion/go/lib/log"
+	"github.com/scionproto/scion/go/lib/snet"
+	"github.com/scionproto/scion/go/lib/snet/squic"
+
+	log "github.com/inconshreveable/log15"
+)
+
+func printUsage() {
+	fmt.Println("netcat [flags] host-address port")
+	fmt.Println("netcat [flags] -l port")
+	fmt.Println("The host address is specified as ISD-AS,[IP Address]")
+	fmt.Println("Example SCION address: 17-ffaa:1:bfd,[127.0.0.1]:42002")
+	fmt.Println("Available flags:")
+	fmt.Println("  -h: Show help")
+	fmt.Println("  -local: Local SCION address (default localhost)")
+	fmt.Println("  -b: Send or expect an extra (throw-away) byte before the actual data")
+	fmt.Println("  -tlsKey: TLS key path, only needed when listening (default: ./key.pem)")
+	fmt.Println("  -tlsCertificate: TLS certificate path, only needed when listening (default: ./certificate.pem)")
+}
+
+func main() {
+	scionlog.SetupLogConsole("debug")
+
+	log.Debug("Launching netcat")
+
+	var (
+		remoteAddressString string
+		port                uint16
+		localAddrString     string
+
+		quicTLSKeyPath         string
+		quicTLSCertificatePath string
+
+		extraByte bool
+		listen    bool
+	)
+	flag.Usage = printUsage
+	flag.StringVar(&remoteAddressString, "local", "", "Local address string")
+	flag.StringVar(&quicTLSKeyPath, "tlsKey", "./key.pem", "TLS key path")
+	flag.StringVar(&quicTLSCertificatePath, "tlsCert", "./certificate.pem", "TLS certificate path")
+	flag.BoolVar(&extraByte, "b", false, "Expect extra byte")
+	flag.BoolVar(&listen, "l", false, "Listen mode")
+	flag.Parse()
+
+	tail := flag.Args()
+	if !(len(tail) == 1 && listen) && !(len(tail) == 2 && !listen) {
+		printUsage()
+		golog.Panicf("Incorrect number of arguments! Arguments: %v", tail)
+	}
+
+	remoteAddressString = tail[0]
+	port64, err := strconv.ParseUint(tail[len(tail)-1], 10, 16)
+	if err != nil {
+		printUsage()
+		golog.Panicf("Can't parse port string %v: %v", port64, err)
+	}
+	port = uint16(port64)
+
+	if localAddrString == "" {
+		localAddrString, err = scionutil.GetLocalhostString()
+		if err != nil {
+			golog.Panicf("Error getting localhost: %v", err)
+		}
+	}
+
+	localAddr, err := snet.AddrFromString(localAddrString)
+	if err != nil {
+		golog.Panicf("Error parsing local address: %v", err)
+	}
+
+	// Initialize SCION library
+	err = scionutil.InitSCION(localAddr)
+	if err != nil {
+		golog.Panicf("Error initializing SCION connection: %v", err)
+	}
+
+	var (
+		sess   quic.Session
+		stream quic.Stream
+	)
+
+	if listen {
+		err := squic.Init(quicTLSKeyPath, quicTLSCertificatePath)
+		if err != nil {
+			golog.Panicf("Error initializing squic: %v", err)
+		}
+
+		sess, stream = doListen(localAddr, extraByte)
+	} else {
+		remoteAddr, err := snet.AddrFromString(fmt.Sprintf("%s:%v", remoteAddressString, port))
+		if err != nil {
+			golog.Panicf("Can't parse remote address %s: %v", remoteAddressString)
+		}
+
+		sess, stream = doDial(localAddr, remoteAddr, extraByte)
+	}
+
+	close := func() {
+		err := stream.Close()
+		if err != nil {
+			log.Warn("Error closing stream: %v", err)
+		}
+		err = sess.Close(nil)
+		if err != nil {
+			log.Warn("Error closing session: %v", err)
+		}
+	}
+
+	var once sync.Once
+	go func() {
+		io.Copy(os.Stdout, stream)
+		once.Do(close)
+	}()
+	io.Copy(stream, os.Stdin)
+	once.Do(close)
+}
+
+func doListen(localAddr *snet.Addr, extraByte bool) (quic.Session, quic.Stream) {
+	listener, err := squic.ListenSCION(nil, localAddr, &quic.Config{KeepAlive: true})
+	if err != nil {
+		golog.Panicf("Can't listen on address %v: %v", localAddr, err)
+	}
+
+	sess, err := listener.Accept()
+	if err != nil {
+		golog.Panicf("Can't accept listener: %v", err)
+	}
+
+	stream, err := sess.AcceptStream()
+	if err != nil {
+		golog.Panicf("Can't accept stream: %v", err)
+	}
+
+	log.Debug("Connected!")
+
+	if extraByte {
+		(*bufio.NewReader(stream)).ReadByte()
+
+		log.Debug("Received extra byte!")
+	}
+
+	return sess, stream
+}
+
+func doDial(localAddr, remoteAddr *snet.Addr, extraByte bool) (quic.Session, quic.Stream) {
+	sess, err := squic.DialSCION(nil, localAddr, remoteAddr, &quic.Config{KeepAlive: true})
+	if err != nil {
+		golog.Panicf("Can't dial remote address %v: %v", remoteAddr, err)
+	}
+
+	stream, err := sess.OpenStreamSync()
+	if err != nil {
+		golog.Panicf("Can't open stream: %v", err)
+	}
+
+	log.Debug("Connected!")
+
+	if extraByte {
+		_, err := stream.Write([]byte{71})
+		if err != nil {
+			golog.Panicf("Error writing extra byte: %v", err)
+		}
+
+		log.Debug("Sent extra byte!")
+	}
+
+	return sess, stream
+}