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remove the risk of file descriptor reuse from arping #17

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remove the risk of file descriptor reuse from arping #17

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3 changes: 1 addition & 2 deletions arping.go
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Original file line number Diff line number Diff line change
Expand Up @@ -121,7 +121,6 @@ func PingOverIface(dstIP net.IP, iface net.Interface) (net.HardwareAddr, time.Du
if err != nil {
return nil, 0, err
}
defer sock.deinitialize()

type PingResult struct {
mac net.HardwareAddr
Expand All @@ -131,6 +130,7 @@ func PingOverIface(dstIP net.IP, iface net.Interface) (net.HardwareAddr, time.Du
pingResultChan := make(chan PingResult, 1)

go func() {
defer sock.deinitialize()
// send arp request
verboseLog.Printf("arping '%s' over interface: '%s' with address: '%s'\n", dstIP, iface.Name, srcIP)
if sendTime, err := sock.send(request); err != nil {
Expand Down Expand Up @@ -163,7 +163,6 @@ func PingOverIface(dstIP net.IP, iface net.Interface) (net.HardwareAddr, time.Du
case pingResult := <-pingResultChan:
return pingResult.mac, pingResult.duration, pingResult.err
case <-time.After(timeout):
sock.deinitialize()
return nil, 0, ErrTimeout
}
}
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5 changes: 4 additions & 1 deletion arping_linux.go
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Original file line number Diff line number Diff line change
Expand Up @@ -23,12 +23,15 @@ func initialize(iface net.Interface) (s *LinuxSocket, err error) {
}

func (s *LinuxSocket) send(request arpDatagram) (time.Time, error) {
socketTimeout := timeout.Nanoseconds()
t := syscall.NsecToTimeval(socketTimeout)
syscall.SetsockoptTimeval(s.sock, syscall.SOL_SOCKET, syscall.SO_SNDTIMEO, &t)
return time.Now(), syscall.Sendto(s.sock, request.MarshalWithEthernetHeader(), 0, &s.toSockaddr)
}

func (s *LinuxSocket) receive() (arpDatagram, time.Time, error) {
buffer := make([]byte, 128)
socketTimeout := timeout.Nanoseconds() * 2
socketTimeout := timeout.Nanoseconds()
t := syscall.NsecToTimeval(socketTimeout)
syscall.SetsockoptTimeval(s.sock, syscall.SOL_SOCKET, syscall.SO_RCVTIMEO, &t)
n, _, err := syscall.Recvfrom(s.sock, buffer, 0)
Expand Down