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package com.lumaserv.bgp.protocol.message;
import com.lumaserv.bgp.protocol.IPPrefix;
import com.lumaserv.bgp.protocol.attribute.PathAttribute;
import lombok.Getter;
import lombok.Setter;
import java.util.ArrayList;
import java.util.List;
@Getter
@Setter
public class BGPUpdate {
List<IPPrefix> withdrawnPrefixes = new ArrayList<>();
List<PathAttribute> attributes = new ArrayList<>();
List<IPPrefix> prefixes = new ArrayList<>();
public BGPUpdate(byte[] message) {
int routesLength = ((message[0] & 0xFF) << 8) | (message[1] & 0xFF);
int offset = 2;
int offsetOffset = 2;
while ((offset - offsetOffset) < routesLength) {
IPPrefix prefix = new IPPrefix()
.setLength(message[offset])
.setAddress(new byte[4]);
offset++;
int addressLen = (int) Math.ceil(prefix.getLength() / 8d);
System.arraycopy(message, offset, prefix.getAddress(), 0, addressLen);
offset += addressLen;
withdrawnPrefixes.add(prefix);
}
int attributesLength = ((message[offset] & 0xFF) << 8) | (message[offset + 1] & 0xFF);
offset += 2;
offsetOffset = offset;
while ((offset - offsetOffset) < attributesLength) {
byte flags = message[offset];
byte typeCode = message[offset + 1];
int length = message[offset + 2] & 0xFF;
offset += 3;
if((flags & 0b0001_0000) > 0) {
length <<= 8;
length |= message[offset] & 0xFF;
offset++;
}
byte[] data = new byte[length];
System.arraycopy(message, offset, data, 0, length);
offset += length;
attributes.add(PathAttribute.from(typeCode, data));
}
while (offset < message.length) {
IPPrefix prefix = new IPPrefix()
.setLength(message[offset])
.setAddress(new byte[4]);
offset++;
int addressLen = (int) Math.ceil(prefix.getLength() / 8d);
System.arraycopy(message, offset, prefix.getAddress(), 0, addressLen);
offset += addressLen;
prefixes.add(prefix);
}
}
}
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