Add native protocol service plugins

plugins/services/dnstcp.go

@@ -0,0 +1,79 @@
+//go:build plugin_dnstcp || !plugin_selective
+
+package services
+
+import (
+	"context"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"time"
+
+	"github.com/shadow1ng/fscan/common"
+	"github.com/shadow1ng/fscan/plugins"
+)
+
+type DNSTCPPlugin struct {
+	plugins.BasePlugin
+}
+
+func NewDNSTCPPlugin() *DNSTCPPlugin {
+	return &DNSTCPPlugin{BasePlugin: plugins.NewBasePlugin("dnstcp")}
+}
+
+func (p *DNSTCPPlugin) Scan(ctx context.Context, info *common.HostInfo, session *common.ScanSession) *ScanResult {
+	timeout := session.Config.Timeout
+	if timeout <= 0 {
+		timeout = 3 * time.Second
+	}
+
+	addr := fmt.Sprintf("%s:%d", info.Host, info.Port)
+	conn, err := session.DialTCP(ctx, "tcp", addr, timeout)
+	if err != nil {
+		return &ScanResult{Success: false, Service: "dns"}
+	}
+	defer conn.Close()
+
+	queryID := randomUint16()
+	query := buildDNSRootNSQuery(queryID)
+	frame := make([]byte, 2, len(query)+2)
+	binary.BigEndian.PutUint16(frame, uint16(len(query)))
+	frame = append(frame, query...)
+
+	_ = conn.SetDeadline(time.Now().Add(timeout))
+	if _, err := conn.Write(frame); err != nil {
+		return &ScanResult{Success: false, Service: "dns"}
+	}
+
+	var lenBuf [2]byte
+	if _, err := io.ReadFull(conn, lenBuf[:]); err != nil {
+		return &ScanResult{Success: false, Service: "dns"}
+	}
+	respLen := int(binary.BigEndian.Uint16(lenBuf[:]))
+	if respLen < 12 || respLen > 4096 {
+		return &ScanResult{Success: false, Service: "dns"}
+	}
+
+	resp := make([]byte, respLen)
+	if _, err := io.ReadFull(conn, resp); err != nil {
+		return &ScanResult{Success: false, Service: "dns"}
+	}
+
+	banner, ok := parseDNSResponse(resp, queryID)
+	if !ok {
+		return &ScanResult{Success: false, Service: "dns"}
+	}
+
+	return &ScanResult{
+		Success: true,
+		Type:    plugins.ResultTypeService,
+		Service: "dns",
+		Banner:  banner,
+	}
+}
+
+func init() {
+	RegisterPluginWithPorts("dnstcp", func() Plugin {
+		return NewDNSTCPPlugin()
+	}, []int{53})
+}