seccat (to test sio)

cmd/seccat/.gitignore

+seccat

cmd/seccat/seccat.go

+// package main provides an implementation of netcat using the secio package.
+// This means the channel is encrypted (and MACed).
+// It is meant to exercise the spipe package.
+// Usage:
+//    seccat [<local address>] <remote address>
+//    seccat -l <local address>
+//
+// Address format is: [host]:port
+package main
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"os/signal"
+	"syscall"
+
+	ci "github.com/jbenet/go-ipfs/crypto"
+	secio "github.com/jbenet/go-ipfs/crypto/secio"
+	peer "github.com/jbenet/go-ipfs/peer"
+	u "github.com/jbenet/go-ipfs/util"
+)
+
+var verbose = false
+
+// Usage prints out the usage of this module.
+// Assumes flags use go stdlib flag pacakage.
+var Usage = func() {
+	text := `seccat - secure netcat in Go
+
+Usage:
+
+  listen: %s [<local address>] <remote address>
+  dial:   %s -l <local address>
+
+Address format is Go's: [host]:port
+`
+
+	fmt.Fprintf(os.Stderr, text, os.Args[0], os.Args[0])
+	flag.PrintDefaults()
+}
+
+type args struct {
+	listen     bool
+	verbose    bool
+	debug      bool
+	localAddr  string
+	remoteAddr string
+	// keyfile    string
+	keybits int
+}
+
+func parseArgs() args {
+	var a args
+
+	// setup + parse flags
+	flag.BoolVar(&a.listen, "listen", false, "listen for connections")
+	flag.BoolVar(&a.listen, "l", false, "listen for connections (short)")
+	flag.BoolVar(&a.verbose, "v", true, "verbose")
+	flag.BoolVar(&a.debug, "debug", false, "debugging")
+	// flag.StringVar(&a.keyfile, "key", "", "private key file")
+	flag.IntVar(&a.keybits, "keybits", 2048, "num bits for generating private key")
+	flag.Usage = Usage
+	flag.Parse()
+	osArgs := flag.Args()
+
+	if len(osArgs) < 1 {
+		exit("")
+	}
+
+	if a.verbose {
+		out("verbose on")
+	}
+
+	if a.listen {
+		a.localAddr = osArgs[0]
+	} else {
+		if len(osArgs) > 1 {
+			a.localAddr = osArgs[0]
+			a.remoteAddr = osArgs[1]
+		} else {
+			a.remoteAddr = osArgs[0]
+		}
+	}
+
+	return a
+}
+
+func main() {
+	args := parseArgs()
+	verbose = args.verbose
+	if args.debug {
+		u.SetDebugLogging()
+	}
+
+	go func() {
+		// wait until we exit.
+		sigc := make(chan os.Signal, 1)
+		signal.Notify(sigc, syscall.SIGABRT)
+		<-sigc
+		panic("ABORT! ABORT! ABORT!")
+	}()
+
+	if err := connect(args); err != nil {
+		exit("%s", err)
+	}
+}
+
+func setupPeer(a args) (peer.Peer, peer.Peerstore, error) {
+	if a.keybits < 1024 {
+		return nil, nil, errors.New("Bitsize less than 1024 is considered unsafe.")
+	}
+
+	out("generating key pair...")
+	sk, pk, err := ci.GenerateKeyPair(ci.RSA, a.keybits)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	ps := peer.NewPeerstore()
+	peer, err := ps.WithKeyPair(sk, pk)
+	if err != nil {
+		return nil, nil, err
+	}
+	out("local peer id: %s", peer.ID())
+	return peer, ps, nil
+}
+
+func connect(args args) error {
+	p, ps, err := setupPeer(args)
+	if err != nil {
+		return err
+	}
+
+	var conn net.Conn
+	if args.listen {
+		conn, err = Listen(args.localAddr)
+	} else {
+		conn, err = Dial(args.localAddr, args.remoteAddr)
+	}
+	if err != nil {
+		return err
+	}
+
+	// log everything that goes through conn
+	rwc := &logRW{n: "conn", rw: conn}
+
+	// OK, let's setup the channel.
+	sg := secio.SessionGenerator{Local: p, Peerstore: ps}
+	sess, err := sg.NewSession(nil, rwc)
+	if err != nil {
+		return err
+	}
+	out("remote peer id: %s", sess.RemotePeer().ID())
+	netcat(sess.ReadWriter().(io.ReadWriteCloser))
+	return nil
+}
+
+// Listen listens and accepts one incoming UDT connection on a given port,
+// and pipes all incoming data to os.Stdout.
+func Listen(localAddr string) (net.Conn, error) {
+	l, err := net.Listen("tcp", localAddr)
+	if err != nil {
+		return nil, err
+	}
+	out("listening at %s", l.Addr())
+
+	c, err := l.Accept()
+	if err != nil {
+		return nil, err
+	}
+	out("accepted connection from %s", c.RemoteAddr())
+
+	// done with listener
+	l.Close()
+
+	return c, nil
+}
+
+// Dial connects to a remote address and pipes all os.Stdin to the remote end.
+// If localAddr is set, uses it to Dial from.
+func Dial(localAddr, remoteAddr string) (net.Conn, error) {
+
+	var laddr net.Addr
+	var err error
+	if localAddr != "" {
+		laddr, err = net.ResolveTCPAddr("tcp", localAddr)
+		if err != nil {
+			return nil, fmt.Errorf("failed to resolve address %s", localAddr)
+		}
+	}
+
+	if laddr != nil {
+		out("dialing %s from %s", remoteAddr, laddr)
+	} else {
+		out("dialing %s", remoteAddr)
+	}
+
+	d := net.Dialer{LocalAddr: laddr}
+	c, err := d.Dial("tcp", remoteAddr)
+	if err != nil {
+		return nil, err
+	}
+	out("connected to %s", c.RemoteAddr())
+
+	return c, nil
+}
+
+func netcat(c io.ReadWriteCloser) {
+	out("piping stdio to connection")
+
+	done := make(chan struct{}, 2)
+
+	go func() {
+		n, _ := io.Copy(c, os.Stdin)
+		out("sent %d bytes", n)
+		done <- struct{}{}
+	}()
+	go func() {
+		n, _ := io.Copy(os.Stdout, c)
+		out("received %d bytes", n)
+		done <- struct{}{}
+	}()
+
+	// wait until we exit.
+	sigc := make(chan os.Signal, 1)
+	signal.Notify(sigc, syscall.SIGHUP, syscall.SIGINT,
+		syscall.SIGTERM, syscall.SIGQUIT)
+
+	select {
+	case <-done:
+	case <-sigc:
+		return
+	}
+
+	c.Close()
+}

cmd/seccat/util.go

+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	u "github.com/jbenet/go-ipfs/util"
+)
+
+var log = u.Logger("seccat")
+
+func exit(format string, vals ...interface{}) {
+	if format != "" {
+		fmt.Fprintf(os.Stderr, "seccat: error: "+format+"\n", vals...)
+	}
+	Usage()
+	os.Exit(1)
+}
+
+func out(format string, vals ...interface{}) {
+	if verbose {
+		fmt.Fprintf(os.Stderr, "seccat: "+format+"\n", vals...)
+	}
+}
+
+type logRW struct {
+	n  string
+	rw io.ReadWriter
+}
+
+func (r *logRW) Read(buf []byte) (int, error) {
+	n, err := r.rw.Read(buf)
+	if err == nil {
+		log.Debugf("%s read: %v", r.n, buf)
+	}
+	return n, err
+}
+
+func (r *logRW) Write(buf []byte) (int, error) {
+	log.Debugf("%s write: %v", r.n, buf)
+	return r.rw.Write(buf)
+}
+
+func (r *logRW) Close() error {
+	c, ok := r.rw.(io.Closer)
+	if ok {
+		return c.Close()
+	}
+	return nil
+}