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Simplifies scanner timeouts
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@robgonnella @actions-user
robgonnella authored and actions-user committed Jul 14, 2024
1 parent ed4a1d7 commit 5b26400
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Showing 3 changed files with 41 additions and 121 deletions.
2 changes: 1 addition & 1 deletion README.md
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Original file line number Diff line number Diff line change
@@ -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.
Expand Down
62 changes: 11 additions & 51 deletions pkg/scanner/arpscan.go
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Original file line number Diff line number Diff line change
Expand Up @@ -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
}

Expand All @@ -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 {
Expand Down Expand Up @@ -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)
Expand All @@ -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()

Expand Down Expand Up @@ -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 {
Expand Down Expand Up @@ -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()
}
98 changes: 29 additions & 69 deletions pkg/scanner/synscan.go
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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 {
Expand Down Expand Up @@ -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)
Expand All @@ -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()

Expand Down Expand Up @@ -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 {
Expand Down Expand Up @@ -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()
}

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