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package com.lumaserv.bgp.protocol.message;
import com.lumaserv.bgp.protocol.DataBuilder;
import com.lumaserv.bgp.protocol.IPPrefix;
import com.lumaserv.bgp.protocol.attribute.PathAttribute;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
@NoArgsConstructor
@Getter
@Setter
public class BGPUpdate implements DataBuilder {
List<IPPrefix> withdrawnPrefixes = new ArrayList<>();
List<PathAttribute> attributes = new ArrayList<>();
List<IPPrefix> prefixes = new ArrayList<>();
public BGPUpdate(ByteBuffer message) {
int routesLength = message.getShort() & 0xFFFF;
int offset = 2;
int offsetOffset = 2;
while ((offset - offsetOffset) < routesLength) {
IPPrefix prefix = new IPPrefix()
.setLength(message.get())
.setAddress(new byte[4]);
offset++;
int addressLen = (int) Math.ceil(prefix.getLength() / 8d);
message.get(prefix.getAddress(), 0, addressLen);
offset += addressLen;
withdrawnPrefixes.add(prefix);
}
int attributesLength = message.getShort() & 0xFFFF;
offset += 2;
offsetOffset = offset;
while ((offset - offsetOffset) < attributesLength) {
byte flags = message.get();
byte typeCode = message.get();
int length = message.get() & 0xFF;
offset += 3;
if((flags & 0b0001_0000) > 0) {
length <<= 8;
length |= message.get() & 0xFF;
offset++;
}
byte[] data = new byte[length];
message.get(data);
offset += length;
PathAttribute attr = PathAttribute.from(typeCode, data);
attributes.add(attr);
}
while (message.hasRemaining()) {
IPPrefix prefix = new IPPrefix()
.setLength(message.get())
.setAddress(new byte[4]);
offset++;
int addressLen = (int) Math.ceil(prefix.getLength() / 8d);
message.get(prefix.getAddress(), 0, addressLen);
offset += addressLen;
prefixes.add(prefix);
}
}
public void build(ByteBuffer message) {
int first = message.position();
message.putShort((short)0); // Withdrawn
message.putShort((short)0); // Attributes
// TODO
int pos = message.position();
for (PathAttribute attr: attributes) {
// FIXME add header
byte flags = 0b0100_0000; // TODO
int start = message.position();
message.put(flags);
message.put(attr.getTypeCode());
message.put((byte)0); // Dummy length
attr.build(message);
int length = message.position() - (start + 3);
if (length > 255)
throw new RuntimeException("attribute length > 255");
message.put(start + 2, (byte)(length & 0xFF));
}
int attributesLength = message.position() - pos;
message.putShort(first + 2, (short)attributesLength);
for (IPPrefix prefix : prefixes) {
message.put((byte)prefix.getLength());
int addressLen = (int) Math.ceil(prefix.getLength() / 8d);
message.put(prefix.getAddress(), 0, addressLen);
}
}
}
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