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pcap_importer.go
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pcap_importer.go
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/*
* This file is part of caronte (https://github.com/eciavatta/caronte).
* Copyright (c) 2020 Emiliano Ciavatta.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 3.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package main
import (
"context"
"errors"
"net"
"os"
"path"
"path/filepath"
"sort"
"sync"
"time"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
"github.com/google/gopacket/pcap"
"github.com/google/gopacket/tcpassembly"
log "github.com/sirupsen/logrus"
)
const PcapsBasePath = "pcaps/"
const ProcessingPcapsBasePath = PcapsBasePath + "processing/"
const initialAssemblerPoolSize = 16
const importUpdateProgressInterval = 100 * time.Millisecond
const MAX_PCAPS = 100
type PcapImporter struct {
storage Storage
streamPool *tcpassembly.StreamPool
assemblers []*tcpassembly.Assembler
sessions map[string]ImportingSession
mAssemblers sync.Mutex
mSessions sync.Mutex
serverNet net.IPNet
notificationController *NotificationController
}
type ImportingSession struct {
ID string `json:"id" bson:"_id"`
StartedAt time.Time `json:"started_at" bson:"started_at"`
Size int64 `json:"size" bson:"size"`
CompletedAt time.Time `json:"completed_at" bson:"completed_at,omitempty"`
ProcessedPackets int `json:"processed_packets" bson:"processed_packets"`
InvalidPackets int `json:"invalid_packets" bson:"invalid_packets"`
PacketsPerService map[uint16]flowCount `json:"packets_per_service" bson:"packets_per_service"`
ImportingError string `json:"importing_error" bson:"importing_error,omitempty"`
cancelFunc context.CancelFunc
completed chan string
}
type flowCount [2]int
func NewPcapImporter(storage Storage, serverNet net.IPNet, rulesManager RulesManager,
notificationController *NotificationController) *PcapImporter {
streamPool := tcpassembly.NewStreamPool(NewBiDirectionalStreamFactory(storage, serverNet, rulesManager))
var result []ImportingSession
if err := storage.Find(ImportingSessions).All(&result); err != nil {
log.WithError(err).Panic("failed to retrieve importing sessions")
}
sessions := make(map[string]ImportingSession)
for _, session := range result {
sessions[session.ID] = session
}
return &PcapImporter{
storage: storage,
streamPool: streamPool,
assemblers: make([]*tcpassembly.Assembler, 0, initialAssemblerPoolSize),
sessions: sessions,
mAssemblers: sync.Mutex{},
mSessions: sync.Mutex{},
serverNet: serverNet,
notificationController: notificationController,
}
}
// Import a pcap file to the database. The pcap file must be present at the fileName path. If the pcap is already
// going to be imported or if it has been already imported in the past the function returns an error. Otherwise it
// create a new session and starts to import the pcap, and returns immediately the session name (that is the sha256
// of the pcap).
func (pi *PcapImporter) ImportPcap(fileName string, flushAll bool) (string, error) {
switch filepath.Ext(fileName) {
case ".pcap":
case ".pcapng":
default:
deleteProcessingFile(fileName)
return "", errors.New("invalid file extension")
}
hash, err := Sha256Sum(ProcessingPcapsBasePath + fileName)
if err != nil {
log.WithError(err).Panic("failed to calculate pcap sha256")
deleteProcessingFile(fileName)
}
pi.mSessions.Lock()
if _, isPresent := pi.sessions[hash]; isPresent {
pi.mSessions.Unlock()
deleteProcessingFile(fileName)
return hash, errors.New("pcap already processed")
}
ctx, cancelFunc := context.WithCancel(context.Background())
session := ImportingSession{
ID: hash,
StartedAt: time.Now(),
Size: FileSize(ProcessingPcapsBasePath + fileName),
PacketsPerService: make(map[uint16]flowCount),
cancelFunc: cancelFunc,
completed: make(chan string),
}
pi.sessions[hash] = session
pi.mSessions.Unlock()
go pi.parsePcap(session, fileName, flushAll, ctx)
return hash, nil
}
func (pi *PcapImporter) GetSessions() []ImportingSession {
pi.mSessions.Lock()
sessions := make([]ImportingSession, 0, len(pi.sessions))
for _, session := range pi.sessions {
sessions = append(sessions, session)
}
sort.Slice(sessions, func(i, j int) bool {
return sessions[i].StartedAt.Before(sessions[j].StartedAt)
})
pi.mSessions.Unlock()
return sessions
}
func (pi *PcapImporter) GetSession(sessionID string) (ImportingSession, bool) {
pi.mSessions.Lock()
defer pi.mSessions.Unlock()
session, isPresent := pi.sessions[sessionID]
return session, isPresent
}
func (pi *PcapImporter) CancelSession(sessionID string) bool {
pi.mSessions.Lock()
session, isPresent := pi.sessions[sessionID]
if isPresent {
session.cancelFunc()
}
pi.mSessions.Unlock()
return isPresent
}
func (pi *PcapImporter) FlushConnections(olderThen time.Time, closeAll bool) (flushed, closed int) {
assembler := pi.takeAssembler()
flushed, closed = assembler.FlushWithOptions(tcpassembly.FlushOptions{
T: olderThen,
CloseAll: closeAll,
})
pi.releaseAssembler(assembler)
return
}
// Read the pcap and save the tcp stream flow to the database
func (pi *PcapImporter) parsePcap(session ImportingSession, fileName string, flushAll bool, ctx context.Context) {
pcapHandle, err := pcap.OpenOffline(ProcessingPcapsBasePath + fileName)
if err != nil {
pi.progressUpdate(session, fileName, false, "failed to process pcap")
log.WithError(err).WithFields(log.Fields{"session": session, "fileName": fileName}).
Error("failed to open pcap")
return
}
packetSource := gopacket.NewPacketSource(pcapHandle, pcapHandle.LinkType())
packetSource.NoCopy = true
assembler := pi.takeAssembler()
packets := packetSource.Packets()
updateProgressInterval := time.Tick(importUpdateProgressInterval)
for {
select {
case <-ctx.Done():
pcapHandle.Close()
pi.releaseAssembler(assembler)
pi.progressUpdate(session, fileName, false, "import process cancelled")
return
default:
}
select {
case packet := <-packets:
if packet == nil {
// we read all the packets
if flushAll {
connectionsClosed := assembler.FlushAll()
log.Debugf("connections closed after flush: %v", connectionsClosed)
}
pcapHandle.Close()
pi.tryDeleteOldPcaps()
pi.releaseAssembler(assembler)
pi.progressUpdate(session, fileName, true, "")
pi.notificationController.Notify("pcap.completed", session)
return
}
session.ProcessedPackets++
if packet.NetworkLayer() == nil {
log.Warn("Invalid packet: no network layer")
session.InvalidPackets++
continue
} else if packet.TransportLayer() == nil {
log.Warn("Invalid packet: no transport layer")
session.InvalidPackets++
continue
} else if packet.TransportLayer().LayerType() != layers.LayerTypeTCP {
log.Warn("Invalid packet: no network or transport layer")
session.InvalidPackets++
continue
}
tcp := packet.TransportLayer().(*layers.TCP)
var servicePort uint16
var index int
isDstServer := pi.serverNet.Contains(packet.NetworkLayer().NetworkFlow().Dst().Raw())
isSrcServer := pi.serverNet.Contains(packet.NetworkLayer().NetworkFlow().Src().Raw())
if isDstServer && !isSrcServer {
servicePort = uint16(tcp.DstPort)
index = 0
} else if isSrcServer && !isDstServer {
servicePort = uint16(tcp.SrcPort)
index = 1
} else {
log.Warn("Invalid packet: source and destination are the same")
session.InvalidPackets++
continue
}
fCount, isPresent := session.PacketsPerService[servicePort]
if !isPresent {
fCount = flowCount{0, 0}
}
fCount[index]++
session.PacketsPerService[servicePort] = fCount
assembler.AssembleWithTimestamp(packet.NetworkLayer().NetworkFlow(), tcp, packet.Metadata().Timestamp)
case <-updateProgressInterval:
pi.progressUpdate(session, fileName, false, "")
}
}
}
func (pi *PcapImporter) tryDeleteOldPcaps() {
sessions := pi.GetSessions()
size := len(sessions)
if size > MAX_PCAPS {
hash := sessions[0].ID
// delete the oldest session pcap file
deletePcapFile(hash)
}
}
func (pi *PcapImporter) progressUpdate(session ImportingSession, fileName string, completed bool, err string) {
if completed {
session.CompletedAt = time.Now()
}
session.ImportingError = err
packetsPerService := session.PacketsPerService
session.PacketsPerService = make(map[uint16]flowCount, len(packetsPerService))
for key, value := range packetsPerService {
session.PacketsPerService[key] = value
}
pi.mSessions.Lock()
pi.sessions[session.ID] = session
pi.mSessions.Unlock()
if completed || session.ImportingError != "" {
if _, _err := pi.storage.Insert(ImportingSessions).One(session); _err != nil {
log.WithError(_err).WithField("session", session).Error("failed to insert importing stats")
}
if completed {
moveProcessingFile(session.ID, fileName)
} else {
deleteProcessingFile(fileName)
}
close(session.completed)
}
}
func (pi *PcapImporter) takeAssembler() *tcpassembly.Assembler {
pi.mAssemblers.Lock()
defer pi.mAssemblers.Unlock()
if len(pi.assemblers) == 0 {
return tcpassembly.NewAssembler(pi.streamPool)
}
index := len(pi.assemblers) - 1
assembler := pi.assemblers[index]
pi.assemblers = pi.assemblers[:index]
return assembler
}
func (pi *PcapImporter) releaseAssembler(assembler *tcpassembly.Assembler) {
pi.mAssemblers.Lock()
pi.assemblers = append(pi.assemblers, assembler)
pi.mAssemblers.Unlock()
}
func deleteProcessingFile(fileName string) {
err := os.Remove(ProcessingPcapsBasePath + fileName)
if err != nil {
log.WithError(err).Error("failed to delete processing file")
}
}
func deletePcapFile(fileName string) {
err := os.Remove(PcapsBasePath + fileName)
if err != nil {
log.WithError(err).Error("failed to delete pcap file")
}
}
func moveProcessingFile(sessionID string, oldFileName string) {
oldExt := path.Ext(oldFileName)
oldpath := ProcessingPcapsBasePath + oldFileName
newpath := PcapsBasePath + sessionID + oldExt
err := os.Rename(oldpath, newpath)
if err != nil {
log.WithError(err).Error("failed to move processed file")
}
}