java抓包后对pcap文件解析示例

Pcap pcap = PcapParser.unpack(is);
is.close();
byte[] t = pcap.getData().get(0).getContent();
byte[] data = Arrays.copyOfRange(t, 42, t.length);

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

/**
 * @author zhouqisheng
 *
 */
public class PcapParser {

 public static Pcap unpack(InputStream is) throws IOException {
  Pcap pcap = null;
  byte[] buffer_4 = new byte[4];
  byte[] buffer_2 = new byte[2];
  pcap = new Pcap();

  PcapHeader header = new PcapHeader();
  int m = is.read(buffer_4);
  if(m != 4){
   return null;
  }
  reverseByteArray(buffer_4);
  header.setMagic(byteArrayToInt(buffer_4, 0));
  m = is.read(buffer_2);
  reverseByteArray(buffer_2);
  header.setMagor_version(byteArrayToShort(buffer_2, 0));
  m = is.read(buffer_2);
  reverseByteArray(buffer_2);
  header.setMinor_version(byteArrayToShort(buffer_2, 0));
  m = is.read(buffer_4);
  reverseByteArray(buffer_4);
  header.setTimezone(byteArrayToInt(buffer_4, 0));
  m = is.read(buffer_4);
  reverseByteArray(buffer_4);
  header.setSigflags(byteArrayToInt(buffer_4, 0));
  m = is.read(buffer_4);
  reverseByteArray(buffer_4);
  header.setSnaplen(byteArrayToInt(buffer_4, 0));
  m = is.read(buffer_4);
  reverseByteArray(buffer_4);
  header.setLinktype(byteArrayToInt(buffer_4, 0));

  pcap.setHeader(header);

  List<PcapData> dataList = new ArrayList<PcapData>();
  while (m > 0) {
   PcapData data = new PcapData();
   m = is.read(buffer_4);
   if (m < 0) {
    break;
   }
   reverseByteArray(buffer_4);
   data.setTime_s(byteArrayToInt(buffer_4, 0));
   m = is.read(buffer_4);
   reverseByteArray(buffer_4);
   data.setTime_ms(byteArrayToInt(buffer_4, 0));
   m = is.read(buffer_4);
   reverseByteArray(buffer_4);
   data.setpLength(byteArrayToInt(buffer_4, 0));
   m = is.read(buffer_4);
   reverseByteArray(buffer_4);
   data.setLength(byteArrayToInt(buffer_4, 0));
   byte[] content = new byte[data.getpLength()];
   m = is.read(content);
   data.setContent(content);

   dataList.add(data);
  }

  pcap.setData(dataList);
  return pcap;
 }

 private static int byteArrayToInt(byte[] b, int offset) {
  int value = 0;
  for (int i = 0; i < 4; i++) {
   int shift = (4 - 1 - i) * 8;
   value += (b[i + offset] & 0x000000FF) << shift;
  }
  return value;
 }

 private static short byteArrayToShort(byte[] b, int offset) {
  short value = 0;
  for (int i = 0; i < 2; i++) {
   int shift = (2 - 1 - i) * 8;
   value += (b[i + offset] & 0x000000FF) << shift;
  }
  return value;
 }

 /**
  * 反转数组
  * @param arr
  */
 private static void reverseByteArray(byte[] arr){
  byte temp;
  int n = arr.length;
  for(int i=0; i<n/2; i++){
   temp = arr[i];
   arr[i] = arr[n-1-i];
   arr[n-1-i] = temp;
  }
 }

}

import java.util.List;

/**
 * @author zhouqisheng
 *
 */
public class Pcap {
 private PcapHeader header;
    private List<PcapData> data;
 public PcapHeader getHeader() {
  return header;
 }
 public void setHeader(PcapHeader header) {
  this.header = header;
 }
 public List<PcapData> getData() {
  return data;
 }
 public void setData(List<PcapData> data) {
  this.data = data;
 }
    @Override
    public String toString(){
     StringBuilder s = new StringBuilder();
     s.append("header{\n");
     s.append(header.toString());
     s.append("}\n");
     s.append("data part count=").append(data.size());

     return s.toString();
    }
}

/**
 * @author zhouqisheng
 *  数据包头
 */
public class PcapData {
 private int time_s;//时间戳（秒）
 private int time_ms;//时间戳（微妙）
 private int pLength;//抓包长度
 private int length;//实际长度
 private byte[] content;//数据
 public int getTime_s() {
  return time_s;
 }
 public void setTime_s(int time_s) {
  this.time_s = time_s;
 }
 public int getTime_ms() {
  return time_ms;
 }
 public void setTime_ms(int time_ms) {
  this.time_ms = time_ms;
 }
 public int getpLength() {
  return pLength;
 }
 public void setpLength(int pLength) {
  this.pLength = pLength;
 }
 public int getLength() {
  return length;
 }
 public void setLength(int length) {
  this.length = length;
 }
 public byte[] getContent() {
  return content;
 }
 public void setContent(byte[] content) {
  this.content = content;
 }

 @Override
 public String toString(){
  StringBuilder s = new StringBuilder();
  s.append("time_s=").append(this.time_s);
  s.append("\ntime_ms=").append(this.time_ms);
  s.append("\npLength=").append(this.pLength);
  s.append("\nlength=").append(this.length);
  return null;
 }
}

/**
 * @author zhouqisheng
 * pcap文件头
 */
public class PcapHeader {
 private int magic;//文件识别头,为0xA1B2C3D4
 private short magor_version;//主要版本
    private short minor_version;//次要版本
    private int timezone;//当地标准时间
    private int sigflags;//时间戳的精度
    private int snaplen;//最大的存储长度
    /**
     * 0            BSD loopback devices, except for later OpenBSD
  1            Ethernet, and Linux loopback devices
  6            802.5 Token Ring
  7            ARCnet
  8            SLIP
  9            PPP
  10           FDDI
  100         LLC/SNAP-encapsulated ATM
  101         “raw IP”, with no link
  102         BSD/OS SLIP
  103         BSD/OS PPP
  104         Cisco HDLC
  105         802.11
  108         later OpenBSD loopback devices (with the AF_value in network byte order)
  113         special Linux “cooked” capture
  114         LocalTalk
     */
    private int linktype;//链路类型
 public int getMagic() {
  return magic;
 }
 public void setMagic(int magic) {
  this.magic = magic;
 }
 public short getMagor_version() {
  return magor_version;
 }
 public void setMagor_version(short magor_version) {
  this.magor_version = magor_version;
 }
 public short getMinor_version() {
  return minor_version;
 }
 public void setMinor_version(short minor_version) {
  this.minor_version = minor_version;
 }
 public int getTimezone() {
  return timezone;
 }
 public void setTimezone(int timezone) {
  this.timezone = timezone;
 }
 public int getSigflags() {
  return sigflags;
 }
 public void setSigflags(int sigflags) {
  this.sigflags = sigflags;
 }
 public int getSnaplen() {
  return snaplen;
 }
 public void setSnaplen(int snaplen) {
  this.snaplen = snaplen;
 }
 public int getLinktype() {
  return linktype;
 }
 public void setLinktype(int linktype) {
  this.linktype = linktype;
 }

 @Override
    public String toString(){
  StringBuilder s = new StringBuilder();
  s.append("magic=").append("0x" + Integer.toHexString(this.magic));
  s.append("\nmagor_version=").append(this.magor_version);
  s.append("\nminor_version=").append(this.minor_version);
  s.append("\ntimezone=").append(this.timezone);
  s.append("\nsigflags=").append(this.sigflags);
  s.append("\nsnaplen=").append(this.snaplen);
  s.append("\nlinktype=").append(this.linktype);
     return s.toString();
    }
}