Refactor - now wireguard based. (#7)

peer/control_conn.go

@@ -0,0 +1,64 @@
+package peer
+
+import (
+	"log"
+	"net"
+	"net/netip"
+
+	"vppn/peer/control"
+)
+
+var _ ControlConn = (*udpControlConn)(nil)
+
+type udpControlConn struct {
+	conn *net.UDPConn
+}
+
+// newUDPControlConn opens a UDP socket bound to localIP:port.
+func newUDPControlConn(localIP netip.Addr, port uint16) (*udpControlConn, error) {
+	addr := net.UDPAddrFromAddrPort(netip.AddrPortFrom(localIP, port))
+	conn, err := net.ListenUDP("udp4", addr)
+	if err != nil {
+		return nil, err
+	}
+	return &udpControlConn{conn: conn}, nil
+}
+
+func (c *udpControlConn) SendPing(dst netip.AddrPort, ping control.Ping, buf []byte) error {
+	_, err := c.conn.WriteToUDP(ping.Marshal(buf), net.UDPAddrFromAddrPort(dst))
+	return err
+}
+
+// run reads incoming ping packets and forwards them to ch until ctx is done.
+// Call this in a goroutine before starting the App event loop.
+func (c *udpControlConn) run(ch chan<- PingEvent) {
+	var buf [control.Size]byte
+	for {
+		n, src, err := c.conn.ReadFromUDP(buf[:])
+		if err != nil {
+			log.Printf("control read: %v", err)
+			continue
+		}
+
+		if n != control.Size {
+			continue
+		}
+
+		ping, err := control.Unmarshal(buf)
+		if err != nil {
+			log.Printf("control unmarshal: %v", err)
+			continue
+		}
+
+		srcIP, ok := netip.AddrFromSlice(src.IP)
+		if !ok {
+			continue
+		}
+
+		ch <- PingEvent{srcVPNIP: srcIP.Unmap(), ping: ping}
+	}
+}
+
+func (c *udpControlConn) Close() error {
+	return c.conn.Close()
+}