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package com.lumaserv.bgp.protocol;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
@Setter
@Getter
@NoArgsConstructor
public class BGPPacket {
Type type;
byte[] message;
public BGPPacket(byte[] packet) {
type = Type.fromValue(packet[18]);
message = new byte[packet.length-19];
System.arraycopy(packet, 19, message, 0, message.length);
}
public byte[] build() {
byte[] packet = new byte[message.length + 19];
Arrays.fill(packet, 0, 16, (byte) 0xFF);
packet[16] = (byte)(packet.length >> 8);
packet[17] = (byte)(packet.length & 0xFF);
packet[18] = type.getValue();
System.arraycopy(message, 0, packet, 19, message.length);
return packet;
}
public static BGPPacket read(InputStream stream) throws IOException {
byte[] packet = new byte[18];
int value;
for(int i=0; i<packet.length; i++) {
value = stream.read();
if(value == -1)
throw new IOException("Unexpected end of stream");
packet[i] = (byte) value;
}
int length = ((packet[16] & 0xFF) << 8) | (packet[17] & 0xFF);
byte[] newPacket = new byte[length];
System.arraycopy(packet, 0, newPacket, 0, packet.length);
packet = newPacket;
for(int i=18; i<packet.length; i++) {
value = stream.read();
if(value == -1)
throw new IOException("Unexpected end of stream");
packet[i] = (byte) value;
}
return new BGPPacket(packet);
}
@AllArgsConstructor
@Getter
public enum Type {
OPEN((byte) 1),
UPDATE((byte) 2),
NOTIFICATION((byte) 3),
KEEPALIVE((byte) 4),
ROUTE_REFRESH((byte) 5);
final byte value;
public static Type fromValue(byte value) {
for(Type t : values()) {
if(t.value == value)
return t;
}
return null;
}
}
}
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