无法使用jpcap打开设备

Question

我在使用jpcap库打开找到的网络设备时遇到问题。我已经安装了winpcap，并在system32和syswow64中安装了jpcap.dll。以下教程代码在尝试打开设备时崩溃。崩溃日志：

PacketCapture: loading native library jpcap.. ok
net.sourceforge.jpcap.capture.CaptureDeviceOpenException: Error opening adapter: The system cannot find the device specified. (20)
    at net.sourceforge.jpcap.capture.PacketCapture.open(Native Method)
    at net.sourceforge.jpcap.capture.PacketCapture.open(PacketCapture.java:57)
    at networksnifferdesktop.NetworkSnifferDesktop.<init>(NetworkSnifferDesktop.java:26)
    at networksnifferdesktop.NetworkSnifferDesktop.main(NetworkSnifferDesktop.java:40)
Java Result: 1

在debug中，我可以看到m_device设置为：

"\Device\NPF_{EC5226CF-3F55-4148-B40E-1FC3F8BB3398}   Realtek PCIe GBE Family Controller"

在以下代码中：

package networksnifferdesktop;

import net.sourceforge.jpcap.capture.*;
import net.sourceforge.jpcap.net.*;

public class NetworkSnifferDesktop
{
    private static final int INFINITE = -1;
    private static final int PACKET_COUNT = 10;

    // BPF filter for capturing any packet
    private static final String FILTER = "";

    private PacketCapture m_pcap;
    private String m_device;

    public NetworkSnifferDesktop() throws Exception
    {
        // Step 1:  Instantiate Capturing Engine
        m_pcap = new PacketCapture();

        // Step 2:  Check for devices
        m_device = m_pcap.findDevice();

        // Step 3:  Open Device for Capturing (requires root)
        m_pcap.open(m_device, true);

        // Step 4:  Add a BPF Filter (see tcpdump documentation)
        m_pcap.setFilter(FILTER, true);

        // Step 5:  Register a Listener for Raw Packets
        m_pcap.addRawPacketListener(new RawPacketHandler());

        // Step 6:  Capture Data (max. PACKET_COUNT packets)
        m_pcap.capture(PACKET_COUNT);
    }

    public static void main(String[] args)
    {
        try
        {
            NetworkSnifferDesktop example = new NetworkSnifferDesktop();
        }
        catch (Exception e)
        {
            e.printStackTrace();
            System.exit(1);
        }
    }
}

class RawPacketHandler implements RawPacketListener
{
    private static int m_counter = 0;

    public void rawPacketArrived(RawPacket data)
    {
        m_counter++;
        System.out.println("Received packet (" + m_counter + ")");
    }
}

Answer 1

如果您的字面意思是一个字符串，其第一个字符是“\ "\Device\NPF_{EC5226CF-3F55-4148-B40E-1FC3F8BB3398} Realtek PCIe GBE Family Controller"”中的"D“，最后一个字符是”控制器“中的"r”，则它不是有效的WinPcap设备名称字符串。

"\Device\NPF_{EC5226CF-3F55-4148-B40E-1FC3F8BB3398}"将是有效的设备名称字符串。

从Jpcap源代码可以看出，findDevice方法似乎没有返回有效的设备名称字符串。它被记录为返回“描述网络设备的字符串”；它返回的是一个包含设备名称字符串、一个换行符、两个空格和设备供应商描述字符串的字符串。This has been reported as a Jpcap bug。

我建议您扫描字符串，查找第一个空白字符(“空白”包括空格和换行符)，并使用设备名传递给open例程，包括但不包括该空白字符。(如果找不到空格字符，请使用整个字符串。)