package org.hxzon.netprotocol.packet;
import org.hxzon.netprotocol.field.ProtocolBitField;
import org.hxzon.netprotocol.field.ProtocolField;
import org.hxzon.netprotocol.field.ProtocolInt31Field;
import org.hxzon.netprotocol.field.ProtocolInt63Field;
import org.hxzon.netprotocol.parse.ProtocolBinding;
import org.hxzon.netprotocol.parse.ProtocolBindingList;
import org.hxzon.netprotocol.parse.ProtocolDescUtil;
import org.hxzon.util.BitUtil;
public class TcpPacket extends Packet {
static {
ProtocolBindingList.addBinding(new ProtocolBinding<Ip4Packet>() {
@Override
public Packet match(Ip4Packet packet) {
if (packet.fetchProtocolCode().getValue() == IpType_Tcp) {
return new TcpPacket();
} else {
return null;
}
}
});
ProtocolDescUtil.putDesc(TcpPacket.class, "tcp");
}
public static final int IpType_Tcp = 6;
private ProtocolInt31Field _sourcePort;
private ProtocolInt31Field _destPort;
private ProtocolInt63Field _sequenceNumber;
//希望接收的下一序号，表示已正确接收了所有序号小于确认号的数据字节
private ProtocolInt63Field _acknowledgementNumber;
private ProtocolBitField _headerLen;
private ProtocolBitField _flag;
private ProtocolInt31Field _windowSize;
private ProtocolInt31Field _checksum;
private ProtocolInt31Field _urgentPointer;
protected int expectHeaderLength() {
return fetchHeaderLen().getValue() * 4;
}
protected ProtocolField[] expectHeaderFields() {
return new ProtocolField[] { fetchSourcePort(), fetchDestPort(), fetchSequenceNumber(), fetchAcknowledgementNumber(), fetchHeaderLen(), fetchFlag(), fetchWindowSize(), fetchChecksum(),
fetchUrgentPointer() };
}
public ProtocolInt31Field fetchSourcePort() {
if (_sourcePort == null) {
_sourcePort = new ProtocolInt31Field("sourcePort", "源端口", 0, 2, true, this);
}
return _sourcePort;
}
public ProtocolInt31Field fetchDestPort() {
if (_destPort == null) {
_destPort = new ProtocolInt31Field("destPort", "目的端口", 2, 2, true, this);
}
return _destPort;
}
public ProtocolInt63Field fetchSequenceNumber() {
if (_sequenceNumber == null) {
_sequenceNumber = new ProtocolInt63Field("sequenceNumber", "序列号", 4, 4, true, this);
}
return _sequenceNumber;
}
public ProtocolInt63Field fetchAcknowledgementNumber() {
if (_acknowledgementNumber == null) {
_acknowledgementNumber = new ProtocolInt63Field("acknowledgementNumber", "确认序列号", 8, 4, true, this);
}
return _acknowledgementNumber;
}
public ProtocolBitField fetchHeaderLen() {
if (_headerLen == null) {
_headerLen = new ProtocolBitField("header len", "头部长度", 12, 0, 4, this) {
public String getValueAsString() {
return (getValue() * 4) + "(=" + getValue() + "*4)";
}
};
}
return _headerLen;
}
public ProtocolBitField fetchFlag() {
if (_flag == null) {
_flag = new ProtocolBitField("flag", "标识", 12, 7, 9, this) {
public String getValueAsString() {
return flagDescription(getValue());
}
};
}
return _flag;
}
public static final int Ns = 1 << 8;
public static final int Cwr = 1 << 7;
public static final int Ece = 1 << 6;
//紧急数据偏移量(紧急指针)有效
public static final int Urg = 1 << 5;
//确认序号有效
public static final int Ack = 1 << 4;
//接收方应该立即将数据提交给应用程序
public static final int Psh = 1 << 3;
//连接复位
public static final int Rst = 1 << 2;
//序号同步(建立连接)
public static final int Syn = 1 << 1;
//发送方字节流结束
public static final int Fin = 1 << 0;
public String flagDescription(int flag) {
StringBuilder sb = new StringBuilder();
if (BitUtil.isSet(flag, Ns)) {
sb.append("ECN-nonce concealment protection,");
}
if (BitUtil.isSet(flag, Cwr)) {
sb.append("Congestion Window Reduced,");
}
if (BitUtil.isSet(flag, Ece)) {
sb.append("ECN-Echo,");
}
if (BitUtil.isSet(flag, Urg)) {
sb.append("Urgent,");
}
if (BitUtil.isSet(flag, Ack)) {
sb.append("Acknowledgment,");
}
if (BitUtil.isSet(flag, Psh)) {
sb.append("Push,");
}
if (BitUtil.isSet(flag, Rst)) {
sb.append("Reset,");
}
if (BitUtil.isSet(flag, Syn)) {
sb.append("Syn,");
}
if (BitUtil.isSet(flag, Fin)) {
sb.append("Fin");
}
return sb.toString();
}
public ProtocolInt31Field fetchWindowSize() {
if (_windowSize == null) {
_windowSize = new ProtocolInt31Field("window size", "窗口大小", 14, 2, true, this);
}
return _windowSize;
}
public ProtocolInt31Field fetchChecksum() {
if (_checksum == null) {
_checksum = new ProtocolInt31Field("check sum", "校验和", 16, 2, true, this);
}
return _checksum;
}
public ProtocolInt31Field fetchUrgentPointer() {
if (_urgentPointer == null) {
_urgentPointer = new ProtocolInt31Field("urgent pointer", "紧急指针", 18, 2, true, this);
}
return _urgentPointer;
}
}