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package processing
// DCSO FEVER
// Copyright (c) 2017, DCSO GmbH
import (
"bytes"
"os"
"strings"
"sync"
"time"
"github.com/DCSO/fever/types"
"github.com/DCSO/fever/util"
"github.com/DCSO/bloom"
log "github.com/sirupsen/logrus"
)
// FlowExtractor is an aggregator that extracts the flows from
// "hosts of interest" and sends them to the backend.
type FlowExtractor struct {
SensorID string
BloomPath string
BloomFilter *bloom.BloomFilter
FlowsMutex sync.RWMutex
flowCount int
Flows *bytes.Buffer
SubmitChannel chan []byte
Submitter util.StatsSubmitter
FlushPeriod time.Duration
FlushCount int
CloseChan chan bool
ClosedChan chan bool
Logger *log.Entry
}
// MakeFlowExtractor creates a new empty FlowExtractor.
func MakeFlowExtractor(flushPeriod time.Duration, flushCount int, bloomPath string, submitter util.StatsSubmitter) (*FlowExtractor, error) {
var bloomFilter *bloom.BloomFilter
if bloomPath != "" {
compressed := false
if strings.HasSuffix(bloomPath, ".gz") {
compressed = true
}
var err error
bloomFilter, err = bloom.LoadFilter(bloomPath, compressed)
if err != nil {
return nil, err
}
}
fe := &FlowExtractor{
FlushPeriod: flushPeriod,
Submitter: submitter,
BloomPath: bloomPath,
Logger: log.WithFields(log.Fields{
"domain": "flow_extractor",
}),
Flows: new(bytes.Buffer),
SubmitChannel: make(chan []byte, 60),
BloomFilter: bloomFilter,
CloseChan: make(chan bool),
ClosedChan: make(chan bool),
FlushCount: flushCount,
flowCount: 0,
}
fe.SensorID, _ = os.Hostname()
return fe, nil
}
func (fe *FlowExtractor) flush() {
fe.FlowsMutex.Lock()
myFlows := fe.Flows
fe.Flows = new(bytes.Buffer)
fe.flowCount = 0
fe.FlowsMutex.Unlock()
select {
case fe.SubmitChannel <- myFlows.Bytes():
break
default:
log.Warning("Flow channel is full, cannot submit message...")
}
}
// Consume processes an Entry, adding the data within to the flows
func (fe *FlowExtractor) Consume(e *types.Entry) error {
fe.FlowsMutex.Lock()
defer fe.FlowsMutex.Unlock()
if fe.BloomFilter != nil {
if !fe.BloomFilter.Check([]byte(e.SrcIP)) && !fe.BloomFilter.Check([]byte(e.DestIP)) {
return nil
}
}
var fev types.FlowEvent
err := fev.FromEntry(e)
if err != nil {
return err
}
err = fev.Marshal(fe.Flows)
fe.flowCount++
return err
}
// Run starts the background aggregation service for this handler
func (fe *FlowExtractor) Run() {
//this goroutine asynchronously submit flow messages
go func() {
for message := range fe.SubmitChannel {
fe.Submitter.Submit(message, "", "application/binary-flows")
}
}()
//this go routine takes care of flushing the flows
go func() {
i := 0 * time.Second
interval := 100 * time.Millisecond
for {
select {
case <-fe.CloseChan:
close(fe.SubmitChannel)
close(fe.ClosedChan)
return
default:
//we flush if the flush period has passed, or if the count
//of events is larger then the flush count
fe.FlowsMutex.Lock()
flowCount := fe.flowCount
fe.FlowsMutex.Unlock()
if i >= fe.FlushPeriod || flowCount > fe.FlushCount {
fe.flush()
i = 0 * time.Second
}
time.Sleep(interval)
i += interval
}
}
}()
}
// Stop causes the aggregator to cease aggregating and submitting data
func (fe *FlowExtractor) Stop(stopChan chan bool) {
close(fe.CloseChan)
<-fe.ClosedChan
close(stopChan)
}
// GetName returns the name of the handler
func (fe *FlowExtractor) GetName() string {
return "Flow extractor"
}
// GetEventTypes returns a slice of event type strings that this handler
// should be applied to
func (fe *FlowExtractor) GetEventTypes() []string {
return []string{"flow"}
}
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