TanSanC

Java JNetPcap Library Packet Capture 

pcap File

테스트 환경 : Win7 64bit, Eclipse, Java 1.8

이클립스와

자바는 설치되어있다고 가정합니다.

JNetPcap 라이브러리 다운로드

저는 x84_64

압축을 풀면

jnetpcap.jar, jnetpcap.dll

두 개의 파일이 보입니다.

1. jnetpcap.jar 은 Eclipse 프로젝트에서 참조 할 수 있도록

Package Explorer > Properties > Java Build Path > Libraries > Add JARs 나 Add External JARs 로 추가하여 줍니다.

다운받은 경로보다는

해당 프로젝트 Eclipse Workspace 내에 두는것을 추천합니다.

한글 경로 때문에 안되는 경우도 있습니다,

2. jnetpcap.dll

C:\Windows\System32 경로에 jnetpcap.dll 파일을 복사하여 줍니다.

이제 설정은 끝났습니다.

테스트 코드는 다음과 같습니다.

import java.io.File;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;

import org.jnetpcap.ByteBufferHandler;
import org.jnetpcap.Pcap;
import org.jnetpcap.PcapDumper;
import org.jnetpcap.PcapHeader;
import org.jnetpcap.PcapIf;

public class Test1 {
	public static void main(String[] args) {
		// pcap.loop(x, dumpHandler, dumper); x 개 패킷을
		// String ofile = "tmp-capture-file.cap"; tmp-capture-file.cap 파일로 저장


		List alldevs = new ArrayList(); // Will be filled with
														// NICs
		StringBuilder errbuf = new StringBuilder(); // For any error msgs

		/***************************************************************************
		 * First get a list of devices on this system
		 **************************************************************************/
		int r = Pcap.findAllDevs(alldevs, errbuf);
		if (r == Pcap.NOT_OK || alldevs.isEmpty()) {
			System.err.printf("Can't read list of devices, error is %s\n", errbuf.toString());
			return;
		}
		PcapIf device = alldevs.get(0); // We know we have atleast 1 device

		/***************************************************************************
		 * Second we open up the selected device
		 **************************************************************************/
		int snaplen = 64 * 1024; // Capture all packets, no trucation
		int flags = Pcap.MODE_PROMISCUOUS; // capture all packets
		int timeout = 10 * 1000; // 10 seconds in millis
		Pcap pcap = Pcap.openLive(device.getName(), snaplen, flags, timeout, errbuf);
		if (pcap == null) {
			System.err.printf("Error while opening device for capture: %s\n", errbuf.toString());
			return;
		}

		/***************************************************************************
		 * Third we create a PcapDumper and associate it with the pcap capture
		 ***************************************************************************/
		String ofile = "tmp-capture-file.cap";
		PcapDumper dumper = pcap.dumpOpen(ofile); // output file

		/***************************************************************************
		 * Fouth we create a packet handler which receives packets and tells the
		 * dumper to write those packets to its output file
		 **************************************************************************/
		ByteBufferHandler dumpHandler = new ByteBufferHandler() {

			public void nextPacket(PcapHeader arg0, ByteBuffer arg1, PcapDumper arg2) {
				// TODO Auto-generated method stub
				dumper.dump(arg0, arg1);
			}
		};

		/***************************************************************************
		 * Fifth we enter the loop and tell it to capture 10 packets. We pass in
		 * the dumper created in step 3
		 **************************************************************************/
		pcap.loop(10, dumpHandler, dumper);

		File file = new File(ofile);
		System.out.printf("%s file has %d bytes in it!\n", ofile, file.length());

		/***************************************************************************
		 * Last thing to do is close the dumper and pcap handles
		 **************************************************************************/
		dumper.close(); // Won't be able to delete without explicit close
		pcap.close();

		if (file.exists()) {
			// file.delete(); // Cleanup
		}	
	}
}