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packetbeat.go
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packetbeat.go
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package beater
import (
"flag"
"fmt"
"runtime"
"sync"
"time"
"github.com/elastic/beats/libbeat/beat"
"github.com/elastic/beats/libbeat/common/droppriv"
"github.com/elastic/beats/libbeat/logp"
"github.com/elastic/beats/libbeat/service"
"github.com/tsg/gopacket/layers"
"github.com/elastic/beats/packetbeat/config"
"github.com/elastic/beats/packetbeat/decoder"
"github.com/elastic/beats/packetbeat/flows"
"github.com/elastic/beats/packetbeat/procs"
"github.com/elastic/beats/packetbeat/protos"
"github.com/elastic/beats/packetbeat/protos/icmp"
"github.com/elastic/beats/packetbeat/protos/tcp"
"github.com/elastic/beats/packetbeat/protos/udp"
"github.com/elastic/beats/packetbeat/publish"
"github.com/elastic/beats/packetbeat/sniffer"
)
// Beater object. Contains all objects needed to run the beat
type Packetbeat struct {
PbConfig config.Config
CmdLineArgs CmdLineArgs
Pub *publish.PacketbeatPublisher
Sniff *sniffer.SnifferSetup
services []interface {
Start()
Stop()
}
}
type CmdLineArgs struct {
File *string
Loop *int
OneAtAtime *bool
TopSpeed *bool
Dumpfile *string
PrintDevices *bool
WaitShutdown *int
}
var cmdLineArgs CmdLineArgs
const (
defaultQueueSize = 2048
defaultBulkQueueSize = 0
)
func init() {
cmdLineArgs = CmdLineArgs{
File: flag.String("I", "", "Read packet data from specified file"),
Loop: flag.Int("l", 1, "Loop file. 0 - loop forever"),
OneAtAtime: flag.Bool("O", false, "Read packets one at a time (press Enter)"),
TopSpeed: flag.Bool("t", false, "Read packets as fast as possible, without sleeping"),
Dumpfile: flag.String("dump", "", "Write all captured packets to this libpcap file"),
PrintDevices: flag.Bool("devices", false, "Print the list of devices and exit"),
WaitShutdown: flag.Int("waitstop", 0, "Additional seconds to wait before shutting down"),
}
}
func New() *Packetbeat {
pb := &Packetbeat{}
pb.CmdLineArgs = cmdLineArgs
return pb
}
// Handle custom command line flags
func (pb *Packetbeat) HandleFlags(b *beat.Beat) error {
// -devices CLI flag
if *pb.CmdLineArgs.PrintDevices {
devs, err := sniffer.ListDeviceNames(true)
if err != nil {
return fmt.Errorf("Error getting devices list: %v\n", err)
}
if len(devs) == 0 {
fmt.Printf("No devices found.")
if runtime.GOOS != "windows" {
fmt.Printf(" You might need sudo?\n")
} else {
fmt.Printf("\n")
}
}
for i, dev := range devs {
fmt.Printf("%d: %s\n", i, dev)
}
return beat.GracefulExit
}
return nil
}
// Loads the beat specific config and overwrites params based on cmd line
func (pb *Packetbeat) Config(b *beat.Beat) error {
// Read beat implementation config as needed for setup
err := b.RawConfig.Unpack(&pb.PbConfig)
if err != nil {
logp.Err("fails to read the beat config: %v, %v", err, pb.PbConfig)
return err
}
cfg := &pb.PbConfig.Packetbeat
// CLI flags over-riding config
if *pb.CmdLineArgs.TopSpeed {
cfg.Interfaces.TopSpeed = true
}
if len(*pb.CmdLineArgs.File) > 0 {
cfg.Interfaces.File = *pb.CmdLineArgs.File
}
cfg.Interfaces.Loop = *pb.CmdLineArgs.Loop
cfg.Interfaces.OneAtATime = *pb.CmdLineArgs.OneAtAtime
if len(*pb.CmdLineArgs.Dumpfile) > 0 {
cfg.Interfaces.Dumpfile = *pb.CmdLineArgs.Dumpfile
}
return nil
}
// Setup packetbeat
func (pb *Packetbeat) Setup(b *beat.Beat) error {
cfg := &pb.PbConfig.Packetbeat
if err := procs.ProcWatcher.Init(cfg.Procs); err != nil {
logp.Critical(err.Error())
return err
}
queueSize := defaultQueueSize
if b.Config.Shipper.QueueSize != nil {
queueSize = *b.Config.Shipper.QueueSize
}
bulkQueueSize := defaultBulkQueueSize
if b.Config.Shipper.BulkQueueSize != nil {
bulkQueueSize = *b.Config.Shipper.BulkQueueSize
}
pb.Pub = publish.NewPublisher(b.Publisher, queueSize, bulkQueueSize)
pb.Pub.Start()
logp.Debug("main", "Initializing protocol plugins")
err := protos.Protos.Init(false, pb.Pub, cfg.Protocols)
if err != nil {
return fmt.Errorf("Initializing protocol analyzers failed: %v", err)
}
logp.Debug("main", "Initializing sniffer")
if err := pb.setupSniffer(); err != nil {
return fmt.Errorf("Initializing sniffer failed: %v", err)
}
// This needs to be after the sniffer Init but before the sniffer Run.
if err := droppriv.DropPrivileges(cfg.RunOptions); err != nil {
return err
}
return nil
}
func (pb *Packetbeat) setupSniffer() error {
cfg := &pb.PbConfig.Packetbeat
withVlans := cfg.Interfaces.With_vlans
_, withICMP := cfg.Protocols["icmp"]
filter := cfg.Interfaces.Bpf_filter
if filter == "" && cfg.Flows == nil {
filter = protos.Protos.BpfFilter(withVlans, withICMP)
}
pb.Sniff = &sniffer.SnifferSetup{}
return pb.Sniff.Init(false, pb.makeWorkerFactory(filter), &pb.PbConfig.Packetbeat.Interfaces)
}
func (pb *Packetbeat) makeWorkerFactory(filter string) sniffer.WorkerFactory {
return func(dl layers.LinkType) (sniffer.Worker, string, error) {
var f *flows.Flows
var err error
if pb.PbConfig.Packetbeat.Flows != nil {
f, err = flows.NewFlows(pb.Pub, pb.PbConfig.Packetbeat.Flows)
if err != nil {
return nil, "", err
}
}
var icmp4 icmp.ICMPv4Processor
var icmp6 icmp.ICMPv6Processor
if cfg, exists := pb.PbConfig.Packetbeat.Protocols["icmp"]; exists {
icmp, err := icmp.New(false, pb.Pub, cfg)
if err != nil {
return nil, "", err
}
icmp4 = icmp
icmp6 = icmp
}
tcp, err := tcp.NewTcp(&protos.Protos)
if err != nil {
return nil, "", err
}
udp, err := udp.NewUdp(&protos.Protos)
if err != nil {
return nil, "", err
}
worker, err := decoder.NewDecoder(f, dl, icmp4, icmp6, tcp, udp)
if err != nil {
return nil, "", err
}
if f != nil {
pb.services = append(pb.services, f)
}
return worker, filter, nil
}
}
func (pb *Packetbeat) Run(b *beat.Beat) error {
// start services
for _, service := range pb.services {
service.Start()
}
var wg sync.WaitGroup
errC := make(chan error, 1)
// Run the sniffer in background
wg.Add(1)
go func() {
defer wg.Done()
err := pb.Sniff.Run()
if err != nil {
errC <- fmt.Errorf("Sniffer main loop failed: %v", err)
}
}()
logp.Debug("main", "Waiting for the sniffer to finish")
wg.Wait()
select {
default:
case err := <-errC:
return err
}
// kill services
for _, service := range pb.services {
service.Stop()
}
waitShutdown := pb.CmdLineArgs.WaitShutdown
if waitShutdown != nil && *waitShutdown > 0 {
time.Sleep(time.Duration(*waitShutdown) * time.Second)
}
return nil
}
func (pb *Packetbeat) Cleanup(b *beat.Beat) error {
if service.WithMemProfile() {
logp.Debug("main", "Waiting for streams and transactions to expire...")
time.Sleep(time.Duration(float64(protos.DefaultTransactionExpiration) * 1.2))
logp.Debug("main", "Streams and transactions should all be expired now.")
}
// TODO:
// pb.TransPub.Stop()
return nil
}
// Called by the Beat stop function
func (pb *Packetbeat) Stop() {
logp.Info("Packetbeat send stop signal")
pb.Sniff.Stop()
}