Add native protocol service plugins

plugins/services/bacnet.go

@@ -0,0 +1,81 @@
+//go:build plugin_bacnet || !plugin_selective
+
+package services
+
+import (
+	"context"
+	"encoding/binary"
+	"fmt"
+	"time"
+
+	"github.com/shadow1ng/fscan/common"
+	"github.com/shadow1ng/fscan/plugins"
+)
+
+var bacnetWhoIs = []byte{0x81, 0x0a, 0x00, 0x0c, 0x01, 0x20, 0xff, 0xff, 0x00, 0xff, 0x10, 0x08}
+
+type BACnetPlugin struct {
+	plugins.BasePlugin
+}
+
+func NewBACnetPlugin() *BACnetPlugin {
+	return &BACnetPlugin{BasePlugin: plugins.NewBasePlugin("bacnet")}
+}
+
+func (p *BACnetPlugin) Scan(ctx context.Context, info *common.HostInfo, session *common.ScanSession) *ScanResult {
+	timeout := session.Config.Timeout
+	if timeout <= 0 {
+		timeout = 3 * time.Second
+	}
+
+	target := fmt.Sprintf("%s:%d", info.Host, info.Port)
+	conn, err := session.DialUDP(ctx, target, timeout)
+	if err != nil {
+		return &ScanResult{Success: false, Service: "bacnet"}
+	}
+	defer conn.Close()
+
+	if _, err := conn.Write(bacnetWhoIs); err != nil {
+		return &ScanResult{Success: false, Service: "bacnet"}
+	}
+
+	buf := make([]byte, 1476)
+	n, err := conn.Read(buf)
+	if err != nil {
+		return &ScanResult{Success: false, Service: "bacnet"}
+	}
+
+	banner, ok := parseBACnetResponse(buf[:n])
+	if !ok {
+		return &ScanResult{Success: false, Service: "bacnet"}
+	}
+
+	return &ScanResult{
+		Success: true,
+		Type:    plugins.ResultTypeService,
+		Service: "bacnet",
+		Banner:  banner,
+	}
+}
+
+func parseBACnetResponse(data []byte) (string, bool) {
+	if len(data) < 6 || data[0] != 0x81 {
+		return "", false
+	}
+	length := int(binary.BigEndian.Uint16(data[2:4]))
+	if length != len(data) {
+		return "", false
+	}
+	for i := 4; i+1 < len(data); i++ {
+		if data[i] == 0x10 && data[i+1] == 0x00 {
+			return "BACnet I-Am response", true
+		}
+	}
+	return "", false
+}
+
+func init() {
+	RegisterUDPPluginWithPorts("bacnet", func() Plugin {
+		return NewBACnetPlugin()
+	}, []int{47808})
+}