From fb8c549e9d3d7143cd6edb7555e06e9fecf5982d Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Sun, 18 Aug 2019 16:52:00 +1000
Subject: [PATCH] Add mse/cmd/mse

---
 go.mod              |  1 +
 go.sum              |  4 ++
 mse/cmd/mse/main.go | 90 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 95 insertions(+)
 create mode 100644 mse/cmd/mse/main.go

diff --git a/go.mod b/go.mod
index 92ab43e4..ba973b75 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@ module github.com/anacrolix/torrent
 require (
 	bazil.org/fuse v0.0.0-20180421153158-65cc252bf669
 	github.com/RoaringBitmap/roaring v0.4.18 // indirect
+	github.com/alexflint/go-arg v1.1.0
 	github.com/anacrolix/dht/v2 v2.0.1
 	github.com/anacrolix/envpprof v0.0.0-20180404065416-323002cec2fa
 	github.com/anacrolix/go-libutp v1.0.2
diff --git a/go.sum b/go.sum
index 0a38c3cf..6cff345d 100644
--- a/go.sum
+++ b/go.sum
@@ -4,6 +4,10 @@ github.com/RoaringBitmap/roaring v0.4.7 h1:eGUudvFzvF7Kxh7JjYvXfI1f7l22/2duFby7r
 github.com/RoaringBitmap/roaring v0.4.7/go.mod h1:8khRDP4HmeXns4xIj9oGrKSz7XTQiJx2zgh7AcNke4w=
 github.com/RoaringBitmap/roaring v0.4.18 h1:nh8Ngxctxt5QAoMLuR7MHJe4jEqpn+EnsdgDWPryQWo=
 github.com/RoaringBitmap/roaring v0.4.18/go.mod h1:D3qVegWTmfCaX4Bl5CrBE9hfrSrrXIr8KVNvRsDi1NI=
+github.com/alexflint/go-arg v1.1.0 h1:92ADei0d3TP0mGBdJ/FNcF54X6uFY7BQfhqkrQt3CCE=
+github.com/alexflint/go-arg v1.1.0/go.mod h1:3Rj4baqzWaGGmZA2+bVTV8zQOZEjBQAPBnL5xLT+ftY=
+github.com/alexflint/go-scalar v1.0.0 h1:NGupf1XV/Xb04wXskDFzS0KWOLH632W/EO4fAFi+A70=
+github.com/alexflint/go-scalar v1.0.0/go.mod h1:GpHzbCOZXEKMEcygYQ5n/aa4Aq84zbxjy3MxYW0gjYw=
 github.com/anacrolix/dht v0.0.0-20180412060941-24cbf25b72a4 h1:0yHJvFiGQhJ1gSHJOR8xzmnx45orEt7uiIB6guf0+zc=
 github.com/anacrolix/dht v0.0.0-20180412060941-24cbf25b72a4/go.mod h1:hQfX2BrtuQsLQMYQwsypFAab/GvHg8qxwVi4OJdR1WI=
 github.com/anacrolix/dht/v2 v2.0.1 h1:gOHJ+OKqJ4Eb48OYStZm4AlWr1/nSA2TWlzb/+t36SA=
diff --git a/mse/cmd/mse/main.go b/mse/cmd/mse/main.go
new file mode 100644
index 00000000..c4311ca3
--- /dev/null
+++ b/mse/cmd/mse/main.go
@@ -0,0 +1,90 @@
+package main
+
+import (
+	"io"
+	"log"
+	"net"
+	"os"
+	"sync"
+
+	"github.com/alexflint/go-arg"
+	"golang.org/x/xerrors"
+
+	"github.com/anacrolix/torrent/mse"
+)
+
+func main() {
+	err := mainErr()
+	if err != nil {
+		log.Fatalf("fatal error: %v", err)
+	}
+}
+
+func mainErr() error {
+	var args = struct {
+		CryptoMethod mse.CryptoMethod
+		Dial         *struct {
+			Network        string `arg:"positional"`
+			Address        string `arg:"positional"`
+			SecretKey      string `arg:"positional"`
+			InitialPayload []byte
+		} `arg:"subcommand""`
+		Listen *struct {
+			Network    string   `arg:"positional"`
+			Address    string   `arg:"positional"`
+			SecretKeys []string `arg:"positional"`
+		} `arg:"subcommand""`
+	}{
+		CryptoMethod: mse.AllSupportedCrypto,
+	}
+	arg.MustParse(&args)
+	if args.Dial != nil {
+		cn, err := net.Dial(args.Dial.Network, args.Dial.Address)
+		if err != nil {
+			return xerrors.Errorf("dialing: %w", err)
+		}
+		defer cn.Close()
+		rw, _, err := mse.InitiateHandshake(cn, []byte(args.Dial.SecretKey), args.Dial.InitialPayload, args.CryptoMethod)
+		if err != nil {
+			return xerrors.Errorf("initiating handshake: %w", err)
+		}
+		doStreaming(rw)
+	}
+	if args.Listen != nil {
+		l, err := net.Listen(args.Listen.Network, args.Listen.Address)
+		if err != nil {
+			return xerrors.Errorf("listening: %w", err)
+		}
+		defer l.Close()
+		cn, err := l.Accept()
+		l.Close()
+		if err != nil {
+			return xerrors.Errorf("accepting: %w", err)
+		}
+		defer cn.Close()
+		rw, _, err := mse.ReceiveHandshake(cn, func(f func([]byte) bool) {
+			for _, sk := range args.Listen.SecretKeys {
+				f([]byte(sk))
+			}
+		}, mse.DefaultCryptoSelector)
+		if err != nil {
+			log.Fatalf("error receiving: %v", err)
+		}
+		doStreaming(rw)
+	}
+	return nil
+}
+
+func doStreaming(rw io.ReadWriter) {
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		defer wg.Done()
+		log.Println(io.Copy(rw, os.Stdin))
+	}()
+	go func() {
+		defer wg.Done()
+		log.Println(io.Copy(os.Stdout, rw))
+	}()
+	wg.Wait()
+}