Add native protocol service plugins

plugins/services/dns.go

@@ -0,0 +1,65 @@
+//go:build plugin_dns || !plugin_selective
+
+package services
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/shadow1ng/fscan/common"
+	"github.com/shadow1ng/fscan/plugins"
+)
+
+type DNSPlugin struct {
+	plugins.BasePlugin
+}
+
+func NewDNSPlugin() *DNSPlugin {
+	return &DNSPlugin{BasePlugin: plugins.NewBasePlugin("dns")}
+}
+
+func (p *DNSPlugin) 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)
+	queryID := randomUint16()
+	query := buildDNSRootNSQuery(queryID)
+
+	conn, err := session.DialUDP(ctx, target, timeout)
+	if err != nil {
+		return &ScanResult{Success: false, Service: "dns"}
+	}
+	defer conn.Close()
+
+	if _, err := conn.Write(query); err != nil {
+		return &ScanResult{Success: false, Service: "dns"}
+	}
+
+	buf := make([]byte, 1500)
+	n, err := conn.Read(buf)
+	if err != nil || n < 12 {
+		return &ScanResult{Success: false, Service: "dns"}
+	}
+
+	banner, ok := parseDNSResponse(buf[:n], queryID)
+	if !ok {
+		return &ScanResult{Success: false, Service: "dns"}
+	}
+
+	return &ScanResult{
+		Success: true,
+		Type:    plugins.ResultTypeService,
+		Service: "dns",
+		Banner:  banner,
+	}
+}
+
+func init() {
+	RegisterUDPPluginWithPorts("dns", func() Plugin {
+		return NewDNSPlugin()
+	}, []int{53})
+}