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https://github.com/tailscale/tailscale.git
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cmd/tsconnect: initial scaffolding for Tailscale Connect browser client
Runs a Tailscale client in the browser (via a WebAssembly build of the wasm package) and allows SSH access to machines. The wasm package exports a newIPN function, which returns a simple JS object with methods like start(), login(), logout() and ssh(). The golang.org/x/crypto/ssh package is used for the SSH client. Terminal emulation and QR code renedring is done via NPM packages (xterm and qrcode respectively), thus we also need a JS toolchain that can install and bundle them. Yarn is used for installation, and esbuild handles loading them and bundling for production serving. Updates #3157 Signed-off-by: Mihai Parparita <mihai@tailscale.com>
This commit is contained in:
Mihai Parparita
committed by
Mihai Parparita
Mihai Parparita
parent
2a22ea3e83
commit
6f5096fa61
411
cmd/tsconnect/wasm/wasm_js.go
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411
cmd/tsconnect/wasm/wasm_js.go
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@@ -0,0 +1,411 @@
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// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// The wasm package builds a WebAssembly module that provides a subset of
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// Tailscale APIs to JavaScript.
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//
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// When run in the browser, a newIPN(config) function is added to the global JS
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// namespace. When called it returns an ipn object with the methods
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// run(callbacks), login(), logout(), and ssh(...).
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package main
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import (
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"bytes"
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"context"
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"encoding/hex"
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"encoding/json"
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"fmt"
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"log"
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"math/rand"
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"net"
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"strings"
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"syscall/js"
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"time"
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"golang.org/x/crypto/ssh"
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"inet.af/netaddr"
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"tailscale.com/control/controlclient"
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"tailscale.com/ipn"
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"tailscale.com/ipn/ipnlocal"
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"tailscale.com/ipn/ipnserver"
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"tailscale.com/ipn/store/mem"
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"tailscale.com/net/netns"
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"tailscale.com/net/tsdial"
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"tailscale.com/safesocket"
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"tailscale.com/tailcfg"
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"tailscale.com/types/logger"
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"tailscale.com/wgengine"
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"tailscale.com/wgengine/netstack"
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"tailscale.com/words"
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)
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func main() {
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js.Global().Set("newIPN", js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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if len(args) != 1 {
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log.Fatal("Usage: newIPN(config)")
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return nil
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}
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return newIPN(args[0])
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}))
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// Keep Go runtime alive, otherwise it will be shut down before newIPN gets
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// called.
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<-make(chan bool)
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}
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func newIPN(jsConfig js.Value) map[string]any {
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netns.SetEnabled(false)
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var logf logger.Logf = log.Printf
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dialer := new(tsdial.Dialer)
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eng, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{
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Dialer: dialer,
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})
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if err != nil {
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log.Fatal(err)
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}
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tunDev, magicConn, dnsManager, ok := eng.(wgengine.InternalsGetter).GetInternals()
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if !ok {
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log.Fatalf("%T is not a wgengine.InternalsGetter", eng)
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}
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ns, err := netstack.Create(logf, tunDev, eng, magicConn, dialer, dnsManager)
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if err != nil {
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log.Fatalf("netstack.Create: %v", err)
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}
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ns.ProcessLocalIPs = true
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ns.ProcessSubnets = true
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if err := ns.Start(); err != nil {
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log.Fatalf("failed to start netstack: %v", err)
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}
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dialer.UseNetstackForIP = func(ip netaddr.IP) bool {
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return true
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}
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dialer.NetstackDialTCP = func(ctx context.Context, dst netaddr.IPPort) (net.Conn, error) {
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return ns.DialContextTCP(ctx, dst)
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}
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jsStateStorage := jsConfig.Get("stateStorage")
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var store ipn.StateStore
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if jsStateStorage.IsUndefined() {
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store = new(mem.Store)
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} else {
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store = &jsStateStore{jsStateStorage}
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}
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srv, err := ipnserver.New(log.Printf, "some-logid", store, eng, dialer, nil, ipnserver.Options{
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SurviveDisconnects: true,
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LoginFlags: controlclient.LoginEphemeral,
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})
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if err != nil {
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log.Fatalf("ipnserver.New: %v", err)
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}
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lb := srv.LocalBackend()
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jsIPN := &jsIPN{
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dialer: dialer,
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srv: srv,
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lb: lb,
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}
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return map[string]any{
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"run": js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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if len(args) != 1 {
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log.Fatal(`Usage: run({
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notifyState(state: int): void,
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notifyNetMap(netMap: object): void,
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notifyBrowseToURL(url: string): void,
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})`)
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return nil
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}
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jsIPN.run(args[0])
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return nil
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}),
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"login": js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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if len(args) != 0 {
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log.Printf("Usage: login()")
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return nil
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}
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jsIPN.login()
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return nil
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}),
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"logout": js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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if len(args) != 0 {
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log.Printf("Usage: logout()")
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return nil
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}
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jsIPN.logout()
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return nil
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}),
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"ssh": js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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if len(args) != 6 {
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log.Printf("Usage: ssh(hostname, writeFn, readFn, rows, cols, onDone)")
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return nil
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}
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go jsIPN.ssh(
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args[0].String(),
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args[1],
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args[2],
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args[3].Int(),
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args[4].Int(),
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args[5])
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return nil
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}),
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}
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}
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type jsIPN struct {
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dialer *tsdial.Dialer
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srv *ipnserver.Server
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lb *ipnlocal.LocalBackend
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}
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func (i *jsIPN) run(jsCallbacks js.Value) {
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notifyState := func(state ipn.State) {
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jsCallbacks.Call("notifyState", int(state))
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}
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notifyState(ipn.NoState)
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i.lb.SetNotifyCallback(func(n ipn.Notify) {
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log.Printf("NOTIFY: %+v", n)
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if n.State != nil {
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notifyState(*n.State)
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}
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if nm := n.NetMap; nm != nil {
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jsNetMap := jsNetMap{
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Self: jsNetMapSelfNode{
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jsNetMapNode: jsNetMapNode{
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Name: nm.Name,
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Addresses: mapSlice(nm.Addresses, func(a netaddr.IPPrefix) string { return a.IP().String() }),
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NodeKey: nm.NodeKey.String(),
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MachineKey: nm.MachineKey.String(),
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},
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MachineStatus: int(nm.MachineStatus),
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},
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Peers: mapSlice(nm.Peers, func(p *tailcfg.Node) jsNetMapPeerNode {
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return jsNetMapPeerNode{
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jsNetMapNode: jsNetMapNode{
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Name: p.Name,
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Addresses: mapSlice(p.Addresses, func(a netaddr.IPPrefix) string { return a.IP().String() }),
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MachineKey: p.Machine.String(),
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NodeKey: p.Key.String(),
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},
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Online: *p.Online,
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TailscaleSSHEnabled: p.Hostinfo.TailscaleSSHEnabled(),
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}
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}),
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}
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if jsonNetMap, err := json.Marshal(jsNetMap); err == nil {
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jsCallbacks.Call("notifyNetMap", string(jsonNetMap))
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} else {
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log.Printf("Could not generate JSON netmap: %v", err)
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}
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}
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if n.BrowseToURL != nil {
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jsCallbacks.Call("notifyBrowseToURL", *n.BrowseToURL)
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}
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})
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go func() {
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err := i.lb.Start(ipn.Options{
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StateKey: "wasm",
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UpdatePrefs: &ipn.Prefs{
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ControlURL: ipn.DefaultControlURL,
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RouteAll: false,
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AllowSingleHosts: true,
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WantRunning: true,
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Hostname: generateHostname(),
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},
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})
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if err != nil {
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log.Printf("Start error: %v", err)
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}
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}()
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go func() {
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ln, _, err := safesocket.Listen("", 0)
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if err != nil {
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log.Fatalf("safesocket.Listen: %v", err)
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}
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err = i.srv.Run(context.Background(), ln)
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log.Fatalf("ipnserver.Run exited: %v", err)
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}()
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}
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func (i *jsIPN) login() {
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go i.lb.StartLoginInteractive()
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}
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func (i *jsIPN) logout() {
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if i.lb.State() == ipn.NoState {
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log.Printf("Backend not running")
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}
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go i.lb.Logout()
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}
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func (i *jsIPN) ssh(host string, writeFn js.Value, setReadFn js.Value, rows, cols int, onDone js.Value) {
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defer onDone.Invoke()
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write := func(s string) {
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writeFn.Invoke(s)
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}
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writeError := func(label string, err error) {
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write(fmt.Sprintf("%s Error: %v\r\n", label, err))
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}
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ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancel()
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c, err := i.dialer.UserDial(ctx, "tcp", net.JoinHostPort(host, "22"))
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if err != nil {
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writeError("Dial", err)
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return
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}
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defer c.Close()
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config := &ssh.ClientConfig{
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HostKeyCallback: ssh.InsecureIgnoreHostKey(),
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}
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sshConn, _, _, err := ssh.NewClientConn(c, host, config)
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if err != nil {
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writeError("SSH Connection", err)
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return
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}
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defer sshConn.Close()
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write("SSH Connected\r\n")
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sshClient := ssh.NewClient(sshConn, nil, nil)
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defer sshClient.Close()
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session, err := sshClient.NewSession()
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if err != nil {
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writeError("SSH Session", err)
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return
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}
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write("Session Established\r\n")
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defer session.Close()
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stdin, err := session.StdinPipe()
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if err != nil {
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writeError("SSH Stdin", err)
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return
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}
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session.Stdout = termWriter{writeFn}
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session.Stderr = termWriter{writeFn}
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setReadFn.Invoke(js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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input := args[0].String()
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_, err := stdin.Write([]byte(input))
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if err != nil {
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writeError("Write Input", err)
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}
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return nil
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}))
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err = session.RequestPty("xterm", rows, cols, ssh.TerminalModes{})
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if err != nil {
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writeError("Pseudo Terminal", err)
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return
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}
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err = session.Shell()
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if err != nil {
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writeError("Shell", err)
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return
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}
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err = session.Wait()
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if err != nil {
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writeError("Exit", err)
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return
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}
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}
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type termWriter struct {
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f js.Value
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}
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func (w termWriter) Write(p []byte) (n int, err error) {
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r := bytes.Replace(p, []byte("\n"), []byte("\n\r"), -1)
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w.f.Invoke(string(r))
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return len(p), nil
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}
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type jsNetMap struct {
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Self jsNetMapSelfNode `json:"self"`
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Peers []jsNetMapPeerNode `json:"peers"`
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}
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type jsNetMapNode struct {
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Name string `json:"name"`
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Addresses []string `json:"addresses"`
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MachineStatus int `json:"machineStatus"`
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MachineKey string `json:"machineKey"`
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NodeKey string `json:"nodeKey"`
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}
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type jsNetMapSelfNode struct {
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jsNetMapNode
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MachineStatus int `json:"machineStatus"`
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}
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type jsNetMapPeerNode struct {
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jsNetMapNode
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Online bool `json:"online"`
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TailscaleSSHEnabled bool `json:"tailscaleSSHEnabled"`
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}
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type jsStateStore struct {
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jsStateStorage js.Value
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}
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func (s *jsStateStore) ReadState(id ipn.StateKey) ([]byte, error) {
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jsValue := s.jsStateStorage.Call("getState", string(id))
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if jsValue.String() == "" {
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return nil, ipn.ErrStateNotExist
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}
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return hex.DecodeString(jsValue.String())
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}
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func (s *jsStateStore) WriteState(id ipn.StateKey, bs []byte) error {
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s.jsStateStorage.Call("setState", string(id), hex.EncodeToString(bs))
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return nil
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}
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func mapSlice[T any, M any](a []T, f func(T) M) []M {
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n := make([]M, len(a))
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for i, e := range a {
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n[i] = f(e)
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}
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return n
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}
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func filterSlice[T any](a []T, f func(T) bool) []T {
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n := make([]T, 0, len(a))
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for _, e := range a {
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if f(e) {
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n = append(n, e)
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}
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}
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return n
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}
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func generateHostname() string {
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tails := words.Tails()
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scales := words.Scales()
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if rand.Int()%2 == 0 {
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// JavaScript
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tails = filterSlice(tails, func(s string) bool { return strings.HasPrefix(s, "j") })
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scales = filterSlice(scales, func(s string) bool { return strings.HasPrefix(s, "s") })
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} else {
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// WebAssembly
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tails = filterSlice(tails, func(s string) bool { return strings.HasPrefix(s, "w") })
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scales = filterSlice(scales, func(s string) bool { return strings.HasPrefix(s, "a") })
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}
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tail := tails[rand.Intn(len(tails))]
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scale := scales[rand.Intn(len(scales))]
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return fmt.Sprintf("%s-%s", tail, scale)
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}
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Reference in New Issue
Block a user