Merge pull request #8 from Contextualist/feat-tailscale

Tailscale integration
Contextualist · Sep 23, 2023 · 6b0d92d · 6b0d92d
2 parents faceaa9 + 984fbcb
commit 6b0d92d
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diff --git a/README.md b/README.md
@@ -5,7 +5,7 @@
 Highlights (aka "Why making another file-transfer tool?"):
 
 - Designed for personal use; no need to copy-paste a token / code for each transfer
-- Rendezvous service runs distributively on [serverless edge function](https://deno.com/deploy/docs),
+- Rendezvous service runs distributively on [serverless edge function](https://stackoverflow.blog/2023/02/23/how-edge-functions-move-your-back-end-close-to-your-front-end/),
   a robust solution with low latency worldwide. ([How does this work?](docs/mechanism.md))
 
 Other features:
@@ -15,6 +15,7 @@ Other features:
 - Compression (gzip)
 - Cross platform: Linux, macOS, Windows
 - Support transfering multiple files and directories
+- Optional [Tailscale integration](docs/advanced.md#tailscale-integration)
 
 See also [comparison table with similar tools](#similar-projects).
 
@@ -57,7 +58,7 @@ You can run the sender and receiver in arbitrary order.
 Whenever both sides are up and running, they will attempt to establish a P2P connection.
 If you see messages such as `rendezvous timeout`, at least one side is behind a firewall or a strict NAT that prohibits P2P connection.
 
-For advanced configuration and self-hosting (it's free & takes only 5 minutes!), check out [the docs here](docs/advanced.md).
+For advanced configuration and self-hosting, check out [the docs here](docs/advanced.md).
 
 
 ## Similar projects
@@ -68,7 +69,7 @@ For advanced configuration and self-hosting (it's free & takes only 5 minutes!),
 | LAN                                                          | O                                       | O    | O       | O                                        | O                                       |
 | WAN (local ↔︎ remote)                                         | O                                       | O    | O       | P                                        | O                                       |
 | WAN (remote ↔︎ remote)                                        |                                         | P    | O       | P                                        | O                                       |
-| relay                                                        |                                         |      |         | P                                        | O                                       |
+| relay                                                        |                                         |      | P       | P                                        | O                                       |
 | p2p                                                          |                                         |      | O       | O                                        | O                                       |
 | distributive                                                 |                                         |      | O       | O                                        |                                         |
 
@@ -86,3 +87,8 @@ Apart from the dependencies listed in [`go.mod`](go.mod), this project is also b
 - [**mholt/archiver**](https://github.com/mholt/archiver): tar/untar implementation
 - [**libp2p/go-reuseport**](https://github.com/libp2p/go-reuseport): address reuse for TCP hole-punching
 - [**egoist/bina**](https://github.com/egoist/bina): installation script
+- [**Tailscale**](https://tailscale.com), as one of the connection option, provides a painstaking implementation of NAT traversal and a distributive relay service
+
+## Disclaimer
+
+This project is not associated with Deno Land Inc. or Tailscale Inc.
diff --git a/cmd/acp/main.go b/cmd/acp/main.go
@@ -2,15 +2,16 @@ package main
 
 import (
 	"context"
-	"encoding/base64"
 	"errors"
 	"flag"
 	"fmt"
 	"io"
 	"os"
 
 	tea "github.com/charmbracelet/bubbletea"
+	"github.com/contextualist/acp/pkg/config"
 	"github.com/contextualist/acp/pkg/pnet"
+	"github.com/contextualist/acp/pkg/stream"
 	"github.com/contextualist/acp/pkg/tui"
 )
 
@@ -62,13 +63,13 @@ func main() {
 		return
 	}
 	if *doSetup || *doSetupWith != "" {
-		checkErr(setup(*doSetupWith))
+		checkErr(config.Setup(*doSetupWith))
 		return
 	}
 
 	filenames := flag.Args()
-	conf := mustGetConfig()
-	conf.applyDefault()
+	conf := config.MustGetConfig()
+	conf.ApplyDefault()
 
 	ctx, userCancel := context.WithCancel(context.Background())
 	logger = tui.NewLoggerControl(*debug)
@@ -77,48 +78,61 @@ func main() {
 	tui.RunProgram(loggerModel, userCancel, *destination == "-")
 }
 
-func transfer(ctx context.Context, conf *Config, filenames []string, loggerModel tea.Model) {
+func transfer(ctx context.Context, conf *config.Config, filenames []string, loggerModel tea.Model) {
+	pnet.SetLogger(logger)
+	stream.SetLogger(logger)
 	defer logger.End()
 
-	conn, err := pnet.HolePunching(
-		ctx,
-		conf.Server+"/v2/exchange",
-		conf.ID,
-		len(filenames) > 0,
-		pnet.HolePunchingOptions{
-			UseIPv6: conf.UseIPv6,
-			Ports:   conf.Ports,
-			UPnP:    conf.UPnP,
-		},
-		logger,
-	)
-	if errors.Is(err, context.Canceled) || !checkErr(err) {
+	sinfo := pnet.SelfInfo{ChanName: conf.ID}
+	strategy, errs := tryEach(conf.Strategy, func(name string) (s string, err error) {
+		var d stream.Dialer
+		if d, err = stream.GetDialer(name); err != nil {
+			return
+		}
+		if err = d.Init(*conf); err != nil {
+			return "", fmt.Errorf("failed to init dialer %s: %w", name, err)
+		}
+		d.SetInfo(&sinfo)
+		return name, nil
+	})
+	sinfo.Strategy = strategy
+	if len(strategy) == 0 {
+		checkErr(fmt.Errorf("none of the dialers from the strategy is available: %w", errors.Join(errs...)))
 		return
 	}
 
-	psk, err := base64.StdEncoding.DecodeString(conf.PSK)
-	if !checkErr(err) {
-		return
-	}
-	conn, err = encrypted(conn, psk)
+	info, err := pnet.ExchangeConnInfo(
+		ctx,
+		conf.Server+"/v2/exchange",
+		&sinfo,
+		conf.Ports[0],
+		conf.UseIPv6,
+	)
 	if !checkErr(err) {
 		return
 	}
 
-	stream, _ := conn.(io.ReadWriteCloser)
-	var status *tui.StatusControl
-	if !*debug {
-		status = tui.NewStatusControl()
-		stream = status.Monitor(stream)
-		logger.Next(tui.NewStatusModel(status))
-	}
-
+	var status interface{ Next(tea.Model) }
 	if len(filenames) > 0 {
+		var s io.WriteCloser
+		strategyFinal := strategyConsensus(strategy, info.Strategy)
+		s, err = tryUntil(strategyFinal, func(dn string) (io.WriteCloser, error) { return must(stream.GetDialer(dn)).IntoSender(ctx, *info) })
+		if !checkErr(err) {
+			return
+		}
+		s, status = monitor(s)
 		logger.Debugf("sending...")
-		err = sendFiles(filenames, stream)
+		err = sendFiles(filenames, s)
 	} else {
+		var s io.ReadCloser
+		strategyFinal := strategyConsensus(info.Strategy, strategy)
+		s, err = tryUntil(strategyFinal, func(dn string) (io.ReadCloser, error) { return must(stream.GetDialer(dn)).IntoReceiver(ctx, *info) })
+		if !checkErr(err) {
+			return
+		}
+		s, status = monitor(s)
 		logger.Debugf("receiving...")
-		err = receiveFiles(stream)
+		err = receiveFiles(s)
 	}
 
 	if !*debug {
@@ -127,10 +141,22 @@ func transfer(ctx context.Context, conf *Config, filenames []string, loggerModel
 	checkErr(err)
 }
 
+func monitor[T io.Closer](s T) (T, *tui.StatusControl[T]) {
+	var status *tui.StatusControl[T]
+	if !*debug {
+		status = tui.NewStatusControl[T]()
+		s = status.Monitor(s)
+		logger.Next(tui.NewStatusModel(status))
+	}
+	return s, status
+}
+
 func checkErr(err error) bool {
 	if err == nil {
 		return true
 	}
-	exitStatement = err.Error()
+	if !errors.Is(err, context.Canceled) {
+		exitStatement = err.Error()
+	}
 	return false
 }
diff --git a/cmd/acp/strategy.go b/cmd/acp/strategy.go
@@ -0,0 +1,60 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+)
+
+// Merge strategy lists from two parties into a common one,
+// following the precedency set by the first party.
+func strategyConsensus(pa, pb []string) (c []string) {
+	pbSet := make(map[string]struct{}, len(pb))
+	for _, x := range pb {
+		pbSet[x] = struct{}{}
+	}
+
+	for _, x := range pa {
+		if _, ok := pbSet[x]; ok {
+			c = append(c, x)
+		}
+	}
+	logger.Debugf("strategy: a=%v, b=%v, consensus=%v", pa, pb, c)
+	return
+}
+
+// Map a func onto a slice, for each element returning a result or an error
+func tryEach[U, V any](a []U, fn func(U) (V, error)) (r []V, errs []error) {
+	for _, x := range a {
+		y, err := fn(x)
+		if err != nil {
+			logger.Debugf("attempt failed: %v", err)
+			errs = append(errs, err)
+			continue
+		}
+		r = append(r, y)
+	}
+	return
+}
+
+// Map a func onto a slice, until returning the first successful result
+func tryUntil[U, V any](a []U, fn func(U) (V, error)) (r V, err error) {
+	var errs []error
+	for _, x := range a {
+		r, err = fn(x)
+		if err != nil {
+			logger.Debugf("attempt failed: %v", err)
+			errs = append(errs, err)
+			continue
+		}
+		return
+	}
+	err = fmt.Errorf("all attempts failed: %w", errors.Join(errs...))
+	return
+}
+
+func must[T any](t T, err error) T {
+	if err != nil {
+		panic(err)
+	}
+	return t
+}
diff --git a/cmd/acp/stream.go b/cmd/acp/stream.go
@@ -4,21 +4,13 @@ import (
 	"archive/tar"
 	"fmt"
 	"io"
-	"net"
 	"os"
 	"path/filepath"
 	"strings"
 
 	"github.com/klauspost/pgzip"
-	aead "github.com/shadowsocks/go-shadowsocks2/shadowaead"
 )
 
-func encrypted(conn net.Conn, psk []byte) (net.Conn, error) {
-	cipher, err := aead.Chacha20Poly1305(psk)
-	conn = aead.NewConn(conn, cipher)
-	return conn, err
-}
-
 func sendFiles(filenames []string, to io.WriteCloser) (err error) {
 	defer to.Close()
 	z := pgzip.NewWriter(to)

diff --git a/cmd/acp/update.go b/cmd/acp/update.go
@@ -50,6 +50,7 @@ func tryUpdate(exe string, repo string, currTag string) error {
 	if err != nil {
 		return fmt.Errorf("failed to update: %w", err)
 	}
+	fmt.Println("acp has been updated")
 	return nil
 }
 

diff --git a/docs/advanced.md b/docs/advanced.md
@@ -15,6 +15,10 @@ List of configurable options:
 	- `[0]`: bind to a random port;
 	- `[9527]`: bind to port 9527;
 	- `[0,9527]`: bind to a random port and port 9527.
+- `strategy` (default: `["tcp_punch"]`): List of dialers for connection attempts, ordered by preference.
+  Available dialers:
+	- `tcp_punch`: TCP hole-punching
+	- `tailscale`: TCP over Tailnet / Taildrop (requires Tailscale running)
 - `upnp` (default: `false`): Request UPnP port mapping from supported router.
   This may not work for random port.
 
@@ -54,3 +58,10 @@ acp - < tmp-file
 # receiver
 acp -d - > tmp-file
 ```
+
+
+## Tailscale integration
+
+Tailscale has a more robust NAT traversal implementation and [distributed relay fallback](https://tailscale.com/blog/how-tailscale-works/#encrypted-tcp-relays-derp), so it is guarenteed to make connections in all cases. Acp can use Tailscale as a transport backend if you have Tailscale running on both side.
+
+If you have Tailscale running before installing acp, Tailscale support is automatically enabled for acp. Otherwise you can set `strategy: ["tailscale","tcp-punch"]` in config to enable Tailscale support after installing Tailscale.
diff --git a/docs/mechanism.md b/docs/mechanism.md
@@ -59,4 +59,5 @@ The following steps take place to create such mappings and use them for P2P conn
 </p>
 
 *Still curious about the implementation?*
-You can find the rendezvous service in [edge/index.ts](../edge/index.ts) and the client-size of hole-punching in [pkg/pnet/p2p.go](../pkg/pnet/p2p.go).
+You can find the rendezvous service in [edge/index.ts](../edge/index.ts) and the client-side of hole-punching in [pkg/pnet/p2p.go](../pkg/pnet/p2p.go).
+BTW, you would probably find it interesting to read [Tailscale's exteneded discussion on NAT traversal](https://tailscale.com/blog/how-nat-traversal-works/).
diff --git a/edge/index.ts b/edge/index.ts
@@ -3,7 +3,10 @@ type ConnInfo = Deno.ServeHandlerInfo
 interface ClientInfo {
   priAddr: string,
   chanName: string,
-  nPlan: number,
+  strategy?: string[],
+  nPlan?: number,
+  tsAddr?: string,
+  tsCap?: number,
 }
 
 interface AddrPair {
@@ -13,7 +16,10 @@ interface AddrPair {
 
 interface ReplyInfo {
   peerAddrs: AddrPair[],
-  peerNPlan: number,
+  strategy?: string[],
+  peerNPlan?: number,
+  tsAddr?: string,
+  tsCap?: number,
 }
 
 
@@ -25,12 +31,13 @@ async function handleExchangeV2(req: Request, connInfo: ConnInfo): Promise<Respo
 
   const pubAddr = joinHostPort(connInfo.remoteAddr)
   const conn = req.body!.getReader({ mode: "byob" })
-  const { priAddr, chanName, nPlan = 1 }: ClientInfo = JSON.parse(
+  const { priAddr, chanName, nPlan = 1, ...otherInfo }: ClientInfo = JSON.parse(
     new TextDecoder().decode(await receivePacket(conn))
   )
   const reply: ReplyInfo = {
     peerAddrs: [{ pubAddr, priAddr }],
     peerNPlan: nPlan,
+    ...otherInfo,
   }
   const x0 = JSON.stringify(reply)
   //console.log(`accepted from ${x0}`)

diff --git a/go.mod b/go.mod
@@ -18,6 +18,7 @@ require (
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
 	github.com/charmbracelet/lipgloss v0.8.0 // indirect
 	github.com/containerd/console v1.0.4-0.20230313162750-1ae8d489ac81 // indirect
+	github.com/fsnotify/fsnotify v1.6.0
 	github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0 // indirect
 	github.com/klauspost/compress v1.16.7 // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect

diff --git a/go.sum b/go.sum
@@ -10,6 +10,8 @@ github.com/containerd/console v1.0.4-0.20230313162750-1ae8d489ac81 h1:q2hJAaP1k2
 github.com/containerd/console v1.0.4-0.20230313162750-1ae8d489ac81/go.mod h1:YynlIjWYF8myEu6sdkwKIvGQq+cOckRm6So2avqoYAk=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
+github.com/fsnotify/fsnotify v1.6.0 h1:n+5WquG0fcWoWp6xPWfHdbskMCQaFnG6PfBrh1Ky4HY=
+github.com/fsnotify/fsnotify v1.6.0/go.mod h1:sl3t1tCWJFWoRz9R8WJCbQihKKwmorjAbSClcnxKAGw=
 github.com/huin/goupnp v1.2.0 h1:uOKW26NG1hsSSbXIZ1IR7XP9Gjd1U8pnLaCMgntmkmY=
 github.com/huin/goupnp v1.2.0/go.mod h1:gnGPsThkYa7bFi/KWmEysQRf48l2dvR5bxr2OFckNX8=
 github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0 h1:iQTw/8FWTuc7uiaSepXwyf3o52HaUYcV+Tu66S3F5GA=
@@ -55,6 +57,7 @@ golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
 golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20220908164124-27713097b956/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.11.0 h1:eG7RXZHdqOJ1i+0lgLgCpSXAp6M3LYlAo6osgSi0xOM=