ja4sentinel/cmd/ja4sentinel/main.go

// Package main provides the entry point for ja4sentinel
package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"time"

	"ja4sentinel/api"
	"ja4sentinel/internal/capture"
	"ja4sentinel/internal/config"
	"ja4sentinel/internal/fingerprint"
	"ja4sentinel/internal/logging"
	"ja4sentinel/internal/output"
	"ja4sentinel/internal/tlsparse"
)

var (
	// Version information (set via ldflags)
	Version   = "1.0.0"
	BuildTime = "unknown"
	GitCommit = "unknown"
)

func main() {
	// Parse command-line flags
	configPath := flag.String("config", "", "Path to configuration file (YAML)")
	version := flag.Bool("version", false, "Show version information")
	flag.Parse()

	if *version {
		fmt.Printf("ja4sentinel version %s (built %s, commit %s)\n", Version, BuildTime, GitCommit)
		os.Exit(0)
	}

	// Create logger factory
	loggerFactory := &logging.LoggerFactory{}
	appLogger := loggerFactory.NewDefaultLogger()

	appLogger.Info("main", "Starting ja4sentinel", map[string]string{
		"version":   Version,
		"build_time": BuildTime,
		"git_commit": GitCommit,
	})

	// Load configuration
	cfgLoader := config.NewLoader(*configPath)
	appConfig, err := cfgLoader.Load()
	if err != nil {
		appLogger.Error("main", "Failed to load configuration", map[string]string{
			"error": err.Error(),
		})
		os.Exit(1)
	}

	appLogger.Info("main", "Configuration loaded", map[string]string{
		"interface":   appConfig.Core.Interface,
		"listen_ports": formatPorts(appConfig.Core.ListenPorts),
	})

	// Create context with cancellation for graceful shutdown
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Setup signal handling
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)

	// Create pipeline components
	captureEngine := capture.New()
	parser := tlsparse.NewParserWithTimeout(time.Duration(appConfig.Core.FlowTimeoutSec) * time.Second)
	fingerprintEngine := fingerprint.NewEngine()
	outputBuilder := output.NewBuilder()

	outputWriter, err := outputBuilder.NewFromConfig(appConfig)
	if err != nil {
		appLogger.Error("main", "Failed to create output writer", map[string]string{
			"error": err.Error(),
		})
		os.Exit(1)
	}

	// Create channel for raw packets (configurable buffer size)
	bufferSize := appConfig.Core.PacketBufferSize
	if bufferSize <= 0 {
		bufferSize = 1000 // Default fallback
	}
	packetChan := make(chan api.RawPacket, bufferSize)

	// Start capture goroutine
	captureErrChan := make(chan error, 1)
	go func() {
		appLogger.Info("capture", "Starting packet capture", map[string]string{
			"interface": appConfig.Core.Interface,
		})
		err := captureEngine.Run(appConfig.Core, packetChan)
		close(packetChan) // Close channel to signal packet processor to shut down
		captureErrChan <- err
	}()

	// Process packets
	go func() {
		for {
			select {
			case <-ctx.Done():
				appLogger.Info("main", "Packet processor shutting down", nil)
				return
			case pkt, ok := <-packetChan:
				if !ok {
					return
				}

				// Parse TLS ClientHello
				clientHello, err := parser.Process(pkt)
				if err != nil {
					appLogger.Warn("tlsparse", "Failed to parse TLS ClientHello", map[string]string{
						"error": err.Error(),
					})
					continue
				}
				if clientHello == nil {
					continue // Not a TLS ClientHello packet
				}

				appLogger.Debug("tlsparse", "ClientHello extracted", map[string]string{
					"src_ip":  clientHello.SrcIP,
					"src_port": fmt.Sprintf("%d", clientHello.SrcPort),
					"dst_ip":  clientHello.DstIP,
					"dst_port": fmt.Sprintf("%d", clientHello.DstPort),
				})

				// Generate fingerprints
				fingerprints, err := fingerprintEngine.FromClientHello(*clientHello)
				if err != nil {
					appLogger.Warn("fingerprint", "Failed to generate fingerprints", map[string]string{
						"error": err.Error(),
					})
					continue
				}

				appLogger.Debug("fingerprint", "Fingerprints generated", map[string]string{
					"src_ip": clientHello.SrcIP,
					"ja4":    fingerprints.JA4,
				})

				// Create log record
				logRecord := api.NewLogRecord(*clientHello, fingerprints)

				// Write output
				if err := outputWriter.Write(logRecord); err != nil {
					appLogger.Error("output", "Failed to write log record", map[string]string{
						"error": err.Error(),
					})
				}
			}
		}
	}()

	// Wait for shutdown signal or capture error
	select {
	case sig := <-sigChan:
		appLogger.Info("main", "Received shutdown signal", map[string]string{
			"signal": sig.String(),
		})
	case err := <-captureErrChan:
		if err != nil {
			appLogger.Error("capture", "Capture engine failed", map[string]string{
				"error": err.Error(),
			})
		}
	}

	// Graceful shutdown
	appLogger.Info("main", "Shutting down...", nil)
	cancel()

	// Close components
	if err := captureEngine.Close(); err != nil {
		appLogger.Error("main", "Failed to close capture engine", map[string]string{
			"error": err.Error(),
		})
	}

	if err := parser.Close(); err != nil {
		appLogger.Error("main", "Failed to close parser", map[string]string{
			"error": err.Error(),
		})
	}

	if closer, ok := outputWriter.(interface{ Close() error }); ok {
		if err := closer.Close(); err != nil {
			appLogger.Error("main", "Failed to close output writer", map[string]string{
				"error": err.Error(),
			})
		}
	}

	appLogger.Info("main", "ja4sentinel stopped", nil)
}

// formatPorts formats a slice of ports as a comma-separated string
func formatPorts(ports []uint16) string {
	if len(ports) == 0 {
		return ""
	}
	result := fmt.Sprintf("%d", ports[0])
	for _, port := range ports[1:] {
		result += fmt.Sprintf(",%d", port)
	}
	return result
}