client-interface-cleanup (#6)

Refactoring and code cleanup. Improved client command interface.

README.md

@@ -65,9 +65,10 @@ AmbientCapabilities=CAP_NET_BIND_SERVICE CAP_NET_ADMIN
 Type=simple
 User=user
 WorkingDirectory=/home/user/
-ExecStart=/home/user/vppn -name mynetwork -hub-address https://my.hub -api-key 1234567890
+ExecStart=/home/user/vppn run my_net_name https://my.hub my_api_key
 Restart=always
 RestartSec=8
+TimeoutStopSec=24
 
 [Install]
 WantedBy=multi-user.target

cmd/vppn/main.go

@@ -7,5 +7,5 @@ import (
 
 func main() {
 	log.SetFlags(0)
-	peer.Main()
+	peer.Main2()
 }

go.mod

@@ -1,15 +1,15 @@
 module vppn
 
-go 1.24.1
+go 1.25.1
 
 require (
-	git.crumpington.com/lib/go v0.9.0
-	golang.org/x/crypto v0.36.0
-	golang.org/x/sys v0.31.0
+	git.crumpington.com/lib/go v0.9.1
+	golang.org/x/crypto v0.42.0
+	golang.org/x/sys v0.36.0
 )
 
 require (
-	github.com/mattn/go-sqlite3 v1.14.24 // indirect
-	golang.org/x/net v0.37.0 // indirect
-	golang.org/x/text v0.23.0 // indirect
+	github.com/mattn/go-sqlite3 v1.14.32 // indirect
+	golang.org/x/net v0.44.0 // indirect
+	golang.org/x/text v0.29.0 // indirect
 )

go.sum

@@ -1,12 +1,12 @@
-git.crumpington.com/lib/go v0.9.0 h1:QXoMhsycSgEUWNiiPZWl0jgBls+NI9TNR5Z6nNXslCM=
-git.crumpington.com/lib/go v0.9.0/go.mod h1:i3DXiPDo/pgPMHAxUTpyo1Xj2spcvXwXcBef3aSYlnQ=
-github.com/mattn/go-sqlite3 v1.14.24 h1:tpSp2G2KyMnnQu99ngJ47EIkWVmliIizyZBfPrBWDRM=
-github.com/mattn/go-sqlite3 v1.14.24/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
-golang.org/x/crypto v0.36.0 h1:AnAEvhDddvBdpY+uR+MyHmuZzzNqXSe/GvuDeob5L34=
-golang.org/x/crypto v0.36.0/go.mod h1:Y4J0ReaxCR1IMaabaSMugxJES1EpwhBHhv2bDHklZvc=
-golang.org/x/net v0.37.0 h1:1zLorHbz+LYj7MQlSf1+2tPIIgibq2eL5xkrGk6f+2c=
-golang.org/x/net v0.37.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
-golang.org/x/sys v0.31.0 h1:ioabZlmFYtWhL+TRYpcnNlLwhyxaM9kWTDEmfnprqik=
-golang.org/x/sys v0.31.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
-golang.org/x/text v0.23.0 h1:D71I7dUrlY+VX0gQShAThNGHFxZ13dGLBHQLVl1mJlY=
-golang.org/x/text v0.23.0/go.mod h1:/BLNzu4aZCJ1+kcD0DNRotWKage4q2rGVAg4o22unh4=
+git.crumpington.com/lib/go v0.9.1 h1:xLBzcgiZRB6Ky3Ce9hKE+Ko0YbkA4USF4eJk5i5RJF4=
+git.crumpington.com/lib/go v0.9.1/go.mod h1:5nnfjdnUnj/FHhakaliKQKsKeSkUb0GEUKF3PqRgUXg=
+github.com/mattn/go-sqlite3 v1.14.32 h1:JD12Ag3oLy1zQA+BNn74xRgaBbdhbNIDYvQUEuuErjs=
+github.com/mattn/go-sqlite3 v1.14.32/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
+golang.org/x/crypto v0.42.0 h1:chiH31gIWm57EkTXpwnqf8qeuMUi0yekh6mT2AvFlqI=
+golang.org/x/crypto v0.42.0/go.mod h1:4+rDnOTJhQCx2q7/j6rAN5XDw8kPjeaXEUR2eL94ix8=
+golang.org/x/net v0.44.0 h1:evd8IRDyfNBMBTTY5XRF1vaZlD+EmWx6x8PkhR04H/I=
+golang.org/x/net v0.44.0/go.mod h1:ECOoLqd5U3Lhyeyo/QDCEVQ4sNgYsqvCZ722XogGieY=
+golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k=
+golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/text v0.29.0 h1:1neNs90w9YzJ9BocxfsQNHKuAT4pkghyXc4nhZ6sJvk=
+golang.org/x/text v0.29.0/go.mod h1:7MhJOA9CD2qZyOKYazxdYMF85OwPdEr9jTtBpO7ydH4=

peer/cipher-data.go

@@ -1,7 +1,6 @@
 package peer
 
 import (
-	"bytes"
 	"crypto/aes"
 	"crypto/cipher"
 	"crypto/rand"
@@ -39,10 +38,6 @@ func (sc *dataCipher) Key() [32]byte {
 	return sc.key
 }
 
-func (sc *dataCipher) HasKey(k [32]byte) bool {
-	return bytes.Equal(k[:], sc.key[:])
-}
-
 func (sc *dataCipher) Encrypt(h Header, data, out []byte) []byte {
 	const s = dataHeaderSize
 	out = out[:s+dataCipherOverhead+len(data)]

peer/files.go

@@ -29,6 +29,10 @@ func configDir(netName string) string {
 	return filepath.Join(d, ".vppn", netName)
 }
 
+func lockFilePath(netName string) string {
+	return filepath.Join(configDir(netName), "__lock__")
+}
+
 func peerConfigPath(netName string) string {
 	return filepath.Join(configDir(netName), "config.json")
 }
@@ -41,6 +45,10 @@ func startupCountPath(netName string) string {
 	return filepath.Join(configDir(netName), "startup_count.json")
 }
 
+func statusSocketPath(netName string) string {
+	return filepath.Join(configDir(netName), "status.sock")
+}
+
 func storeJson(x any, outPath string) error {
 	outDir := filepath.Dir(outPath)
 	_ = os.MkdirAll(outDir, 0700)

peer/globals.go

@@ -19,7 +19,7 @@ const (
 
 	controlCipherOverhead = 16
 	dataCipherOverhead    = 16
-	signOverhead          = 64
+	signingOverhead       = 64
 
 	pingInterval                  = 8 * time.Second
 	timeoutInterval               = 30 * time.Second

peer/main.go

@@ -1,23 +1,207 @@
 package peer
 
 import (
-	"flag"
+	"encoding/json"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"net/netip"
 	"os"
+	"time"
 )
 
-func Main() {
-	args := mainArgs{}
+// Usage:
+//
+// vppn netName run
+// vppn netName status
+func Main2() {
+	printUsage := func() {
+		fmt.Fprintf(os.Stderr, `%s COMMAND [ARGUMENTS...]
 
-	flag.StringVar(&args.NetName, "name", "", "[REQUIRED] The network name.")
-	flag.StringVar(&args.HubAddress, "hub-address", "", "[REQUIRED] The hub address.")
-	flag.StringVar(&args.APIKey, "api-key", "", "[REQUIRED] The node's API key.")
-	flag.Parse()
-
-	if args.NetName == "" || args.HubAddress == "" || args.APIKey == "" {
-		flag.Usage()
+Available commands:
+    run
+    status
+    hosts
+`, os.Args[0])
 		os.Exit(1)
 	}
 
-	peer := newPeerMain(args)
-	peer.Run()
+	if len(os.Args) < 2 {
+		printUsage()
+	}
+
+	command := os.Args[1]
+
+	switch command {
+	case "run":
+		main_run()
+	case "status":
+		main_status()
+	case "hosts":
+		main_hosts()
+	default:
+		printUsage()
+	}
+}
+
+// ----------------------------------------------------------------------------
+
+type mainArgs struct {
+	NetName    string
+	HubAddress string
+	APIKey     string
+}
+
+func main_run() {
+	printUsage := func() {
+		fmt.Fprintf(os.Stderr, `Usage: %s run NETWORK_NAME HUB_ADDRESS API_KEY
+
+    NETWORK_NAME
+        Unique name of the network interface created. The network name
+        shouldn't change between invocations of the application.
+
+    HUB_ADDRESS
+        The address of the hub server. This should also contain the scheme, for
+        example https://hub.domain.com/.
+
+    API_KEY
+        The API key assigned to this peer by the hub.
+
+`, os.Args[0])
+		os.Exit(1)
+	}
+
+	if len(os.Args) != 5 {
+		printUsage()
+	}
+
+	args := mainArgs{
+		NetName:    os.Args[2],
+		HubAddress: os.Args[3],
+		APIKey:     os.Args[4],
+	}
+
+	newPeerMain(args).Run()
+}
+
+// ----------------------------------------------------------------------------
+
+func main_status() {
+	printUsage := func() {
+		fmt.Fprintf(os.Stderr, `Usage: %s status NETWORK_NAME
+
+    NETWORK_NAME
+        Unique name of the network interface created.
+
+`, os.Args[0])
+		os.Exit(1)
+	}
+
+	if len(os.Args) != 3 {
+		printUsage()
+	}
+
+	netName := os.Args[2]
+	report := fetchStatusReport(netName)
+
+	fmt.Printf("\n%s Status\n\n", netName)
+
+	if len(report.Network) != 4 {
+		fmt.Printf("Network: %v\n\n", report.Network)
+	} else {
+		nw := report.Network
+		fmt.Printf("%-8s %d.%d.%d.%d/24\n", "Network", nw[0], nw[1], nw[2], nw[3])
+	}
+
+	if report.RelayPeerIP != 0 {
+		fmt.Printf("%-8s %d\n\n", "Relay", report.RelayPeerIP)
+	} else {
+		fmt.Printf("%-8s -\n\n", "Relay")
+	}
+
+	for _, status := range report.Remotes {
+		fmt.Printf("%3d %s\n", status.PeerIP, status.Name)
+		fmt.Printf("    %-11s %v\n", "Up", status.Up)
+
+		pubIP, ok := netip.AddrFromSlice(status.PublicIP)
+		if ok {
+			fmt.Printf("    %-11s %v\n", "Public IP", pubIP)
+		} else {
+			fmt.Printf("    %-11s\n", "Public IP")
+		}
+		fmt.Printf("    %-11s %d\n", "Port", status.Port)
+		fmt.Printf("    %-11s %v\n", "Relay", status.Relay)
+		fmt.Printf("    %-11s %v\n", "Server", status.Server)
+		fmt.Printf("    %-11s %v\n", "Direct", status.Direct)
+		if status.DirectAddr.IsValid() {
+			fmt.Printf("    %-11s %v\n", "Address", status.DirectAddr)
+		}
+		fmt.Println("")
+	}
+}
+
+// ----------------------------------------------------------------------------
+
+func main_hosts() {
+	printUsage := func() {
+		fmt.Fprintf(os.Stderr, `Usage: %s hosts NETWORK_NAME
+
+    NETWORK_NAME
+        Unique name of the network interface created.
+
+`, os.Args[0])
+		os.Exit(1)
+	}
+
+	if len(os.Args) != 3 {
+		printUsage()
+	}
+
+	netName := os.Args[2]
+	state, err := loadNetworkState(netName)
+	if err != nil {
+		log.Fatalf("Failed to load network state: %v", err)
+	}
+
+	config, err := loadPeerConfig(netName)
+	if err != nil {
+		log.Fatalf("Failed to load config: %v", err)
+	}
+
+	nw := config.Network
+	for _, peer := range state.Peers {
+		if peer == nil {
+			continue
+		}
+		fmt.Printf("%d.%d.%d.%d %s\n",
+			nw[0], nw[1], nw[2], peer.PeerIP, peer.Name)
+	}
+	fmt.Println("")
+}
+
+// ----------------------------------------------------------------------------
+
+func fetchStatusReport(netName string) StatusReport {
+	client := http.Client{
+		Transport: &http.Transport{
+			Dial: func(_, _ string) (net.Conn, error) {
+				return net.Dial("unix", statusSocketPath(netName))
+			},
+		},
+		Timeout: 8 * time.Second,
+	}
+
+	getURL := "http://unix" + statusSocketPath(netName)
+	resp, err := client.Get(getURL)
+	if err != nil {
+		log.Fatalf("Failed to get response: %v", err)
+	}
+
+	report := StatusReport{}
+	if err := json.NewDecoder(resp.Body).Decode(&report); err != nil {
+		log.Fatalf("Failed to decode status report: %v", err)
+	}
+
+	return report
 }

peer/mcwriter.go

@@ -15,16 +15,16 @@ func createLocalDiscoveryPacket(localIP byte, signingKey []byte) []byte {
 	}
 	buf := make([]byte, headerSize)
 	h.Marshal(buf)
-	out := make([]byte, headerSize+signOverhead)
+	out := make([]byte, headerSize+signingOverhead)
 	return sign.Sign(out[:0], buf, (*[64]byte)(signingKey))
 }
 
 func headerFromLocalDiscoveryPacket(pkt []byte) (h Header, ok bool) {
-	if len(pkt) != headerSize+signOverhead {
+	if len(pkt) != headerSize+signingOverhead {
 		return
 	}
 
-	h.Parse(pkt[signOverhead:])
+	h.Parse(pkt[signingOverhead:])
 	ok = true
 	return
 }

peer/peer.go

@@ -13,6 +13,8 @@ import (
 	"net/url"
 	"os"
 	"vppn/m"
+
+	"git.crumpington.com/lib/go/flock"
 )
 
 type peerMain struct {
@@ -20,12 +22,7 @@ type peerMain struct {
 	ifReader   *IFReader
 	connReader *ConnReader
 	hubPoller  *HubPoller
-}
-
-type mainArgs struct {
-	NetName    string
-	HubAddress string
-	APIKey     string
+	lockFile   *os.File
 }
 
 func newPeerMain(args mainArgs) *peerMain {
@@ -33,6 +30,14 @@ func newPeerMain(args mainArgs) *peerMain {
 		log.Printf("[Main] "+s, args...)
 	}
 
+	lockFile, err := flock.TryLock(lockFilePath(args.NetName))
+	if err != nil {
+		log.Fatalf("Failed to open lock file: %v", err)
+	}
+	if lockFile == nil {
+		log.Fatalf("Failed to obtain file lock.")
+	}
+
 	config, err := loadPeerConfig(args.NetName)
 	if err != nil {
 		logf("Failed to load configuration: %v", err)
@@ -100,11 +105,15 @@ func newPeerMain(args mainArgs) *peerMain {
 		log.Fatalf("Failed to create hub poller: %v", err)
 	}
 
+	// Start status server.
+	go runStatusServer(g, statusSocketPath(args.NetName))
+
 	return &peerMain{
 		Globals:    g,
 		ifReader:   NewIFReader(g),
 		connReader: NewConnReader(g, conn),
 		hubPoller:  hubPoller,
+		lockFile:   lockFile,
 	}
 }
 

peer/remote.go

@@ -106,6 +106,25 @@ func (r *Remote) encryptControl(conf remoteConfig, packet []byte) []byte {
 	return conf.ControlCipher.Encrypt(h, packet, packet[len(packet):cap(packet)])
 }
 
+func (r *Remote) Status() (RemoteStatus, bool) {
+	conf := r.conf()
+	if conf.Peer == nil {
+		return RemoteStatus{}, false
+	}
+
+	return RemoteStatus{
+		PeerIP:     conf.Peer.PeerIP,
+		Up:         conf.Up,
+		Name:       conf.Peer.Name,
+		PublicIP:   conf.Peer.PublicIP,
+		Port:       conf.Peer.Port,
+		Relay:      conf.Peer.Relay,
+		Server:     conf.Server,
+		Direct:     conf.Direct,
+		DirectAddr: conf.DirectAddr,
+	}, true
+}
+
 // ----------------------------------------------------------------------------
 
 // SendDataTo sends a data packet to the remote, called by the IFReader.

peer/remotefsm.go

@@ -154,6 +154,8 @@ func (r *remoteFSM) stateServer_onInit(msg controlMsg[packetInit]) {
 		Version: version,
 	}
 
+	// Reset traceID to force state update on SYN.
+	r.traceID = 0
 	r.sendControl(conf, init.Marshal(r.buf))
 }
 
@@ -161,23 +163,19 @@ func (r *remoteFSM) stateServer_onSyn(msg controlMsg[packetSyn]) {
 	r.lastSeen = time.Now()
 	p := msg.Packet
 
-	// Before we can respond to this packet, we need to make sure the
-	// route is setup properly.
 	conf := r.conf()
-	logSyn := !conf.Up || conf.Direct != p.Direct
+
+	// New trace ID => Update the route configuration.
+	if p.TraceID != r.traceID {
+		r.traceID = p.TraceID
 
 		conf.Up = true
 		conf.Direct = p.Direct
 		conf.DirectAddr = msg.SrcAddr
 
-	// Update data cipher if the key has changed.
-	if !conf.DataCipher.HasKey(p.SharedKey) {
 		conf.DataCipher = newDataCipherFromKey(p.SharedKey)
-	}
 
 		r.updateConf(conf)
-
-	if logSyn {
 		r.logf("Got SYN.")
 	}
 
@@ -191,13 +189,14 @@ func (r *remoteFSM) stateServer_onSyn(msg controlMsg[packetSyn]) {
 		return
 	}
 
-	// Send probes if not a direct connection.
+	// Send probes if not a direct connection. The server sends probes without
+	// trace IDs unless responding to a client probe.
 	for _, addr := range msg.Packet.PossibleAddrs {
 		if !addr.IsValid() {
 			break
 		}
 		r.logf("Probing %v...", addr)
-		r.sendControlToAddr(packetProbe{TraceID: r.NewTraceID()}.Marshal(r.buf), addr)
+		r.sendControlToAddr(packetProbe{}.Marshal(r.buf), addr)
 	}
 }
 
@@ -213,6 +212,8 @@ func (r *remoteFSM) stateServer_onProbe(msg controlMsg[packetProbe]) {
 func (r *remoteFSM) stateServer_onPingTimer() {
 	conf := r.conf()
 	if time.Since(r.lastSeen) > timeoutInterval && conf.Up {
+		// Reset trace ID to ensure connection goes up on next SYN.
+		r.traceID = 0
 		conf.Up = false
 		r.updateConf(conf)
 		r.logf("Timeout.")
@@ -310,7 +311,7 @@ func (r *remoteFSM) stateClientInit_onPing() stateFunc {
 
 func (r *remoteFSM) enterClient() stateFunc {
 	conf := r.conf()
-	r.probes = make(map[uint64]sentProbe, 8)
+	clear(r.probes)
 
 	r.traceID = r.NewTraceID()
 	r.stateClient_sendSyn(conf)

peer/statusserver.go

@@ -0,0 +1,69 @@
+package peer
+
+import (
+	"encoding/json"
+	"log"
+	"net"
+	"net/http"
+	"net/netip"
+	"os"
+)
+
+type StatusReport struct {
+	Network     []byte
+	RelayPeerIP byte
+	Remotes     []RemoteStatus
+}
+
+type RemoteStatus struct {
+	PeerIP     byte
+	Up         bool
+	Name       string
+	PublicIP   []byte
+	Port       uint16
+	Relay      bool
+	Server     bool
+	Direct     bool
+	DirectAddr netip.AddrPort
+}
+
+func runStatusServer(g Globals, socketPath string) {
+	_ = os.RemoveAll(socketPath)
+
+	handler := func(w http.ResponseWriter, r *http.Request) {
+		report := StatusReport{
+			Network: g.Network,
+			Remotes: make([]RemoteStatus, 0, 255),
+		}
+
+		relay := g.RelayHandler.Load()
+		if relay != nil {
+			if relayStatus, ok := relay.Status(); ok {
+				report.RelayPeerIP = relayStatus.PeerIP
+			}
+		}
+
+		for i := range g.RemotePeers {
+			remote := g.RemotePeers[i].Load()
+			status, ok := remote.Status()
+			if !ok {
+				continue
+			}
+			report.Remotes = append(report.Remotes, status)
+		}
+
+		json.NewEncoder(w).Encode(report)
+	}
+
+	server := http.Server{
+		Handler: http.HandlerFunc(handler),
+	}
+
+	unixListener, err := net.Listen("unix", socketPath)
+	if err != nil {
+		log.Fatalf("Failed to bind to unix socket: %v", err)
+	}
+	if err := server.Serve(unixListener); err != nil {
+		log.Fatalf("Failed to serve on unix socket: %v", err)
+	}
+}