Merge pull request #27 from robgonnella/simplify-scanner-timeouts

Simplifies scanner timeouts

README.md

@@ -1,5 +1,5 @@
 # go-lanscan
-![Coverage](https://img.shields.io/badge/Coverage-91.3%25-brightgreen)
+![Coverage](https://img.shields.io/badge/Coverage-91.6%25-brightgreen)
 
 A network cli and golang package that allows you to perform arp and syn
 scanning on a local area network.

pkg/scanner/arpscan.go

@@ -28,13 +28,11 @@ type ArpScanner struct {
  resultChan chan *ScanResult
  requestNotifier chan *Request
  scanning bool
- lastPacketSentAt time.Time
  timing time.Duration
  idleTimeout time.Duration
  vendorRepo oui.VendorRepo
  hostNamesEnables bool
  scanningMux *sync.RWMutex
- packetSentAtMux *sync.RWMutex
  debug logger.DebugLogger
 }
 
@@ -45,18 +43,16 @@ func NewArpScanner(
  options ...Option,
 ) *ArpScanner {
  scanner := &ArpScanner{
- cancel: make(chan struct{}),
- targets: targets,
- cap: &defaultPacketCapture{},
- networkInfo: networkInfo,
- resultChan: make(chan *ScanResult),
- timing: defaultTiming,
- idleTimeout: defaultIdleTimeout,
- scanning: false,
- lastPacketSentAt: time.Time{},
- scanningMux: &sync.RWMutex{},
- packetSentAtMux: &sync.RWMutex{},
- debug: logger.NewDebugLogger(),
+ cancel: make(chan struct{}),
+ targets: targets,
+ cap: &defaultPacketCapture{},
+ networkInfo: networkInfo,
+ resultChan: make(chan *ScanResult),
+ timing: defaultTiming,
+ idleTimeout: defaultIdleTimeout,
+ scanning: false,
+ scanningMux: &sync.RWMutex{},
+ debug: logger.NewDebugLogger(),
  }
 
  for _, o := range options {
@@ -110,9 +106,6 @@ func (s *ArpScanner) Scan() error {
  s.scanningMux.Unlock()
  s.handle = handle
 
- timeout := make(chan struct{})
-
- go s.startPacketReceiveTimeout(timeout)
  go s.readPackets()
 
  limiter := time.NewTicker(s.timing)
@@ -134,11 +127,7 @@ func (s *ArpScanner) Scan() error {
  })
  }
 
- s.packetSentAtMux.Lock()
- s.lastPacketSentAt = time.Now()
- s.packetSentAtMux.Unlock()
-
- <-timeout
+ time.Sleep(s.idleTimeout)
 
  go s.Stop()
 
@@ -197,31 +186,6 @@ func (s *ArpScanner) SetPacketCapture(cap PacketCapture) {
  s.cap = cap
 }
 
-func (s *ArpScanner) startPacketReceiveTimeout(timeout chan<- struct{}) {
- for {
- select {
- case <-s.cancel:
- go func() {
- timeout <- struct{}{}
- }()
- return
- default:
- s.packetSentAtMux.RLock()
- packetSentAt := s.lastPacketSentAt
- s.packetSentAtMux.RUnlock()
-
- if !packetSentAt.IsZero() && time.Since(packetSentAt) >= s.idleTimeout {
- go func() {
- timeout <- struct{}{}
- }()
- return
- }
-
- time.Sleep(time.Millisecond * 100)
- }
- }
-}
-
 func (s *ArpScanner) readPackets() {
  for {
  select {
@@ -367,8 +331,4 @@ func (s *ArpScanner) reset() {
  s.scanningMux.Lock()
  s.scanning = false
  s.scanningMux.Unlock()
-
- s.packetSentAtMux.Lock()
- s.lastPacketSentAt = time.Time{}
- s.packetSentAtMux.Unlock()
 }

pkg/scanner/synscan.go

@@ -26,23 +26,21 @@ type SynPacket struct {
 
 // SynScanner implements the Scanner interface for SYN scanning
 type SynScanner struct {
- cancel chan struct{}
- networkInfo network.Network
- targets []*ArpScanResult
- ports []string
- listenPort uint16
- cap PacketCapture
- handle PacketCaptureHandle
- resultChan chan *ScanResult
- requestNotifier chan *Request
- scanning bool
- lastPacketSentAt time.Time
- timing time.Duration
- idleTimeout time.Duration
- scanningMux *sync.RWMutex
- packetSentAtMux *sync.RWMutex
- serviceQueryMux *sync.Mutex
- debug logger.DebugLogger
+ cancel chan struct{}
+ networkInfo network.Network
+ targets []*ArpScanResult
+ ports []string
+ listenPort uint16
+ cap PacketCapture
+ handle PacketCaptureHandle
+ resultChan chan *ScanResult
+ requestNotifier chan *Request
+ scanning bool
+ timing time.Duration
+ idleTimeout time.Duration
+ scanningMux *sync.RWMutex
+ serviceQueryMux *sync.Mutex
+ debug logger.DebugLogger
 }
 
 // NewSynScanner returns a new instance of SYNScanner
@@ -54,21 +52,19 @@ func NewSynScanner(
  options ...Option,
 ) *SynScanner {
  scanner := &SynScanner{
- cancel: make(chan struct{}),
- targets: targets,
- networkInfo: networkInfo,
- cap: &defaultPacketCapture{},
- ports: ports,
- listenPort: listenPort,
- resultChan: make(chan *ScanResult),
- timing: defaultTiming,
- idleTimeout: defaultIdleTimeout,
- scanning: false,
- lastPacketSentAt: time.Time{},
- scanningMux: &sync.RWMutex{},
- packetSentAtMux: &sync.RWMutex{},
- serviceQueryMux: &sync.Mutex{},
- debug: logger.NewDebugLogger(),
+ cancel: make(chan struct{}),
+ targets: targets,
+ networkInfo: networkInfo,
+ cap: &defaultPacketCapture{},
+ ports: ports,
+ listenPort: listenPort,
+ resultChan: make(chan *ScanResult),
+ timing: defaultTiming,
+ idleTimeout: defaultIdleTimeout,
+ scanning: false,
+ scanningMux: &sync.RWMutex{},
+ serviceQueryMux: &sync.Mutex{},
+ debug: logger.NewDebugLogger(),
  }
 
  for _, o := range options {
@@ -138,9 +134,6 @@ func (s *SynScanner) Scan() error {
 
  s.handle = handle
 
- timeout := make(chan struct{})
-
- go s.startPacketReceiveTimeout(timeout)
  go s.readPackets()
 
  limiter := time.NewTicker(s.timing)
@@ -163,11 +156,7 @@ func (s *SynScanner) Scan() error {
  }
  }
 
- s.packetSentAtMux.Lock()
- s.lastPacketSentAt = time.Now()
- s.packetSentAtMux.Unlock()
-
- <-timeout
+ time.Sleep(s.idleTimeout)
 
  go s.Stop()
 
@@ -228,31 +217,6 @@ func (s *SynScanner) SetTargets(targets []*ArpScanResult) {
  s.targets = targets
 }
 
-func (s *SynScanner) startPacketReceiveTimeout(timeout chan<- struct{}) {
- for {
- select {
- case <-s.cancel:
- go func() {
- timeout <- struct{}{}
- }()
- return
- default:
- s.packetSentAtMux.RLock()
- packetSentAt := s.lastPacketSentAt
- s.packetSentAtMux.RUnlock()
-
- if !packetSentAt.IsZero() && time.Since(packetSentAt) >= s.idleTimeout {
- go func() {
- timeout <- struct{}{}
- }()
- return
- }
-
- time.Sleep(time.Millisecond * 100)
- }
- }
-}
-
 func (s *SynScanner) readPackets() {
  for {
  select {
@@ -418,8 +382,4 @@ func (s *SynScanner) reset() {
  s.scanningMux.Lock()
  s.scanning = false
  s.scanningMux.Unlock()
-
- s.packetSentAtMux.Lock()
- s.lastPacketSentAt = time.Time{}
- s.packetSentAtMux.Unlock()
 }