Refactor - now wireguard based. (#7)

peer/app.go

@@ -0,0 +1,105 @@
+package peer
+
+import (
+	"net/netip"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
+
+	"vppn/m"
+	"vppn/peer/control"
+	"vppn/peer/multicast"
+	"vppn/peer/wginterface"
+)
+
+var _ WGDevice = (*wginterface.Device)(nil) // compile-time check: Device satisfies WGDevice
+
+const (
+	ControlPort     = 4561
+	PingInterval    = 8 * time.Second
+	TimeoutInterval = 30 * time.Second
+)
+
+// scratchSize is large enough for the biggest buffer either the ping or the
+// multicast path serializes through the shared App scratch.
+const scratchSize = max(control.Size, multicast.SignedPacketSize)
+
+type PingEvent struct {
+	srcVPNIP netip.Addr
+	ping     control.Ping
+}
+
+// App is the peer application. All mutable state lives here and is
+// accessed only from the Run goroutine.
+type App struct {
+	// Identity
+	vpnIP       netip.Addr
+	vpnNet      netip.Prefix
+	privKey     wgtypes.Key
+	pubKey      wgtypes.Key
+	isRelay     bool
+	isPublic    bool
+	localDomain string
+
+	// Infrastructure
+	dev         WGDevice
+	controlConn ControlConn
+
+	// Peer state
+	relay      *Peer
+	peersByKey map[wgtypes.Key]*Peer
+	peersByIP  map[netip.Addr]*Peer
+
+	// Our own external endpoints, learned from Dst fields in incoming pings
+	selfV4 netip.AddrPort
+	selfV6 netip.AddrPort
+
+	// Reusable serialization scratch for outgoing pings and multicast signature
+	// verification. Only touched from the Run goroutine.
+	scratch []byte
+
+	// Event channels fed by background goroutines
+	hubAddCh    <-chan m.Peer
+	hubRemoveCh <-chan wgtypes.Key
+	pingCh      <-chan PingEvent
+	multicastCh <-chan multicast.Packet
+}
+
+// Run is the main event loop. It runs until SIGTERM/SIGINT.
+func (a *App) Run() error {
+	// Establish a clean hosts section before the first poll lands, clearing
+	// any stale entries left by a prior run (e.g. crash, or peers removed
+	// while we were down).
+	a.updateHosts()
+
+	ticker := time.NewTicker(PingInterval)
+	defer ticker.Stop()
+
+	sig := make(chan os.Signal, 1)
+	signal.Notify(sig, syscall.SIGTERM, syscall.SIGINT)
+	defer signal.Stop(sig)
+
+	for {
+		select {
+		case p := <-a.hubAddCh:
+			a.onAddPeer(p)
+		case key := <-a.hubRemoveCh:
+			a.onRemovePeer(key)
+		case e := <-a.pingCh:
+			a.onPing(e)
+		case e := <-a.multicastCh:
+			a.onMulticastDiscovery(e)
+		case <-ticker.C:
+			a.onTick()
+		case <-sig:
+			return a.onShutdown()
+		}
+	}
+}
+
+func (a *App) onShutdown() error {
+	return wginterface.Delete(a.dev.Name())
+}