Golang C.pcap_create函數代碼示例

// OpenLive opens a device and returns a *Handle.
// It takes as arguments the name of the device ("eth0"), the maximum size to
// read for each packet (snaplen), whether to put the interface in promiscuous
// mode, and a timeout.
func OpenLive(device string, snaplen int32, promisc bool, timeout time.Duration) (handle *Handle, _ error) {
	var buf *C.char
	buf = (*C.char)(C.calloc(errorBufferSize, 1))
	defer C.free(unsafe.Pointer(buf))
	var pro C.int
	if promisc {
		pro = 1
	}

	dev := C.CString(device)
	defer C.free(unsafe.Pointer(dev))

	// This copies a bunch of the pcap_open_live implementation from pcap.c:
	cptr := C.pcap_create(dev, buf)
	if cptr == nil {
		return nil, errors.New(C.GoString(buf))
	}
	var status C.int
	if status = C.pcap_set_snaplen(cptr, C.int(snaplen)); status < 0 {
		goto fail
	} else if status = C.pcap_set_promisc(cptr, pro); status < 0 {
		goto fail
	} else if status = C.pcap_set_timeout(cptr, C.int(timeout/time.Millisecond)); status < 0 {
		goto fail
	}
	return newHandle(cptr), nil
fail:
	C.pcap_close(cptr)
	return nil, statusError(status)
}

// NewInactiveHandle creates a new InactiveHandle, which wraps an un-activated PCAP handle.
// Callers of NewInactiveHandle should immediately defer 'CleanUp', as in:
//   inactive := NewInactiveHandle("eth0")
//   defer inactive.CleanUp()
func NewInactiveHandle(device string) (*InactiveHandle, error) {
	buf := (*C.char)(C.calloc(errorBufferSize, 1))
	defer C.free(unsafe.Pointer(buf))
	dev := C.CString(device)
	defer C.free(unsafe.Pointer(dev))

	// This copies a bunch of the pcap_open_live implementation from pcap.c:
	cptr := C.pcap_create(dev, buf)
	if cptr == nil {
		return nil, errors.New(C.GoString(buf))
	}
	return &InactiveHandle{cptr: cptr, device: device}, nil
}

// Create a new capture handle from the given network interface. Noe that this
// may require root privileges.
func Open(dev_name string) (*Handle, error) {
	handle := &Handle{Device: dev_name}

	dev_str := C.CString(dev_name)
	defer C.free(unsafe.Pointer(dev_str))

	err_str := (*C.char)(C.calloc(256, 1))
	defer C.free(unsafe.Pointer(err_str))

	handle.pcap = C.pcap_create(dev_str, err_str)
	if handle == nil {
		return nil, fmt.Errorf(
			"Could not open device: %s", C.GoString(err_str),
		)
	}

	return handle, nil
}

func main() {
	var errbuf = (*C.char)(C.malloc(C.PCAP_ERRBUF_SIZE))
	defer C.free(unsafe.Pointer(errbuf))
	var source = C.CString("any")
	defer C.free(unsafe.Pointer(source))

	pcap_handle := C.pcap_create(source, errbuf)
	if pcap_handle == nil {
		panic("pcap_handle")
	}
	C.pcap_set_buffer_size(pcap_handle, 2*1024*1024)
	C.pcap_set_promisc(pcap_handle, 1)
	C.pcap_set_snaplen(pcap_handle, 512) // more than enough to recognize a WOL packet
	C.pcap_setdirection(pcap_handle, C.PCAP_D_IN)
	if C.pcap_activate(pcap_handle) != 0 {
		panic(C.GoString(C.pcap_geterr(pcap_handle)))
	}

	var bpf_program C.struct_bpf_program
	if C.pcap_compile(pcap_handle, &bpf_program, pcap_filter, 0, 0) != 0 {
		panic(C.GoString(C.pcap_geterr(pcap_handle)))
	}
	if C.pcap_setfilter(pcap_handle, &bpf_program) != 0 {
		panic(C.GoString(C.pcap_geterr(pcap_handle)))
	}

	for {
		var pkt_header *C.struct_pcap_pkthdr
		var pkt_data *C.u_char
		if C.pcap_next_ex(pcap_handle, &pkt_header, &pkt_data) < 0 {
			panic(C.GoString(C.pcap_geterr(pcap_handle)))
		}
		if pkt_data == nil {
			continue
		}
		data := make([]byte, pkt_header.caplen)
		copy(data, (*(*[10000000]byte)(unsafe.Pointer(pkt_data)))[0:])
		from_mac, to_mac := checkwol(data)
		if from_mac != "" {
			fmt.Printf("%v: %v sends WOL to %v\n", time.Now(), from_mac, to_mac)
		}
	}

}

func Create(device string) (handle *Pcap, err error) {
	var buf *C.char
	buf = (*C.char)(C.calloc(ERRBUF_SIZE, 1))
	h := new(Pcap)

	dev := C.CString(device)
	defer C.free(unsafe.Pointer(dev))

	h.cptr = C.pcap_create(dev, buf)
	if nil == h.cptr {
		handle = nil
		err = &pcapError{C.GoString(buf)}
	} else {
		handle = h
	}

	C.free(unsafe.Pointer(buf))
	return
}

// Create will construct a pcap that can be used to set custom settings like a
// larger buffer.  The resulting Pcap must then be started with a call to
// Activate.  See Open for an example list of calls that should be made.
func Create(device string) (*Pcap, error) {
	p := &Pcap{
		Device: device,
		Pchan:  make(chan *pkt.Packet, ChanBuffSize),
		m:      &sync.Mutex{},
	}

	buf := (*C.char)(C.calloc(C.PCAP_ERRBUF_SIZE, 1))
	defer C.free(unsafe.Pointer(buf))

	dev := C.CString(p.Device)
	defer C.free(unsafe.Pointer(dev))

	p.cptr = C.pcap_create(dev, buf)
	if p.cptr == nil {
		return p, errors.New(C.GoString(buf))
	}
	return p, nil
}

// NewInactiveHandle creates a new InactiveHandle, which wraps an un-activated PCAP handle.
// Callers of NewInactiveHandle should immediately defer 'CleanUp', as in:
//   inactive := NewInactiveHandle("eth0")
//   defer inactive.CleanUp()
func NewInactiveHandle(device string) (*InactiveHandle, error) {
	buf := (*C.char)(C.calloc(errorBufferSize, 1))
	defer C.free(unsafe.Pointer(buf))
	dev := C.CString(device)
	defer C.free(unsafe.Pointer(dev))

	// Try to get the interface index, but iy could be something like "any"
	// in which case use 0, which doesn't exist in nature
	deviceIndex := 0
	ifc, err := net.InterfaceByName(device)
	if err == nil {
		deviceIndex = ifc.Index
	}

	// This copies a bunch of the pcap_open_live implementation from pcap.c:
	cptr := C.pcap_create(dev, buf)
	if cptr == nil {
		return nil, errors.New(C.GoString(buf))
	}
	return &InactiveHandle{cptr: cptr, device: device, deviceIndex: deviceIndex}, nil
}