feat(sol): UDP + HTTP listener

server/udp.go

@@ -0,0 +1,107 @@
+package server
+
+import (
+	"fmt"
+	"net"
+	"time"
+
+	"wol-sol-agent/auth"
+	"wol-sol-agent/magicpacket"
+	"wol-sol-agent/system"
+
+	"git.secnex.io/secnex/masterlog"
+)
+
+// UDPServer handles UDP connections for Magic Packets
+type UDPServer struct {
+	port          int
+	authenticator *auth.Authenticator
+}
+
+// NewUDPServer creates a new UDP server
+func NewUDPServer(port int, authenticator *auth.Authenticator) *UDPServer {
+	return &UDPServer{
+		port:          port,
+		authenticator: authenticator,
+	}
+}
+
+// Start starts the UDP server
+func (s *UDPServer) Start(done chan bool) {
+	addr, err := net.ResolveUDPAddr("udp", fmt.Sprintf(":%d", s.port))
+	if err != nil {
+		masterlog.Error("Failed to resolve UDP address", map[string]interface{}{
+			"error": err,
+		})
+		return
+	}
+
+	conn, err := net.ListenUDP("udp", addr)
+	if err != nil {
+		masterlog.Error("Failed to listen on UDP port", map[string]interface{}{
+			"error": err,
+			"port":  s.port,
+		})
+		return
+	}
+	defer conn.Close()
+
+	masterlog.Info("UDP server listening on port", map[string]interface{}{
+		"port": s.port,
+	})
+
+	buffer := make([]byte, 2048)
+
+	for {
+		select {
+		case <-done:
+			return
+		default:
+			conn.SetReadDeadline(time.Now().Add(1 * time.Second))
+			n, clientAddr, err := conn.ReadFromUDP(buffer)
+			if err != nil {
+				if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
+					continue
+				}
+				masterlog.Error("Error reading UDP packet", map[string]interface{}{
+					"error": err,
+				})
+				continue
+			}
+
+			masterlog.Info("Received UDP packet", map[string]interface{}{
+				"bytes":   n,
+				"address": clientAddr,
+			})
+
+			// Check authentication and magic packet
+			if s.isValidAuthenticatedMagicPacket(buffer[:n]) {
+				masterlog.Info("Authenticated Magic Packet detected! Shutting down system...", map[string]interface{}{
+					"address": clientAddr,
+				})
+				system.Shutdown()
+				return
+			}
+			masterlog.Error("Invalid or unauthenticated packet", map[string]interface{}{
+				"address": clientAddr,
+			})
+		}
+	}
+}
+
+// isValidAuthenticatedMagicPacket checks if the packet contains valid authentication
+// followed by a valid Magic Packet
+func (s *UDPServer) isValidAuthenticatedMagicPacket(data []byte) bool {
+	username, password, magicPacketData, ok := magicpacket.ExtractAuthFromPacket(data)
+	if !ok {
+		return false
+	}
+
+	// Verify authentication
+	if !s.authenticator.Verify(username, password) {
+		return false
+	}
+
+	// Check if it's a valid magic packet
+	return magicpacket.IsMagicPacket(magicPacketData)
+}