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package com.lumaserv.bgp;
import com.lumaserv.bgp.protocol.BGPPacket;
import com.lumaserv.bgp.protocol.message.BGPNotification;
import com.lumaserv.bgp.protocol.message.BGPOpen;
import lombok.Getter;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;
public class BGPServer implements Runnable {
final ServerSocket serverSocket;
@Getter
final List<BGPSessionConfiguration> sessionConfigurations = new ArrayList<>();
final List<BGPSession> sessions = new ArrayList<>();
public BGPServer() throws IOException {
this(179);
}
public BGPServer(int port) throws IOException {
serverSocket = new ServerSocket(port);
}
public BGPServer(ServerSocket serverSocket) {
this.serverSocket = serverSocket;
}
private static boolean checkEqual(byte[] a, byte[] b) {
if(a == b)
return true;
if(a == null || b == null)
return false;
if(a.length != b.length)
return false;
for(int i=0; i<a.length; i++) {
if(a[i] != b[i])
return false;
}
return true;
}
public boolean hasCollided(BGPSession session, BGPOpen msg) {
for (BGPSession otherSession : sessions) {
BGPFsm fsm = otherSession.getFsm();
BGPFsm.State state = fsm.getCurrentState();
// May examine OPEN_SENT
if (state == fsm.OPEN_SENT
&& otherSession.getConfiguration() == null)
continue;
// Cannot detect collision
if (state == fsm.IDLE
|| state == fsm.CONNECT
|| state == fsm.ACTIVE)
continue;
// Detect collision
if (session.getInetAddress() != otherSession.getLocalAddress()
|| session.getLocalAddress() != otherSession.getInetAddress())
continue;
// Collision!
if (state == fsm.ESTABLISHED) {
// Close new connection
sessions.remove(session);
return true;
}
byte[] remoteIdentifier;
byte[] localIdentifier = session.getConfiguration()
.getLocalIdentifier();
if (state == fsm.OPEN_SENT) {
remoteIdentifier = otherSession.getConfiguration()
.getRemoteIdentifier();
} else { // state == BGPFsm.OPEN_CONFIRM
remoteIdentifier = otherSession.getRemoteIdentifier();
}
boolean isLocalIdLess = false;
// Compare integer stored in network byte order
for (int i=0; i < 4; i++) {
if (localIdentifier[i] < remoteIdentifier[i]) {
isLocalIdLess = true;
break;
}
}
if (isLocalIdLess) {
// Close existing connection
BGPNotification notification = new BGPNotification()
.setMajorErrorCode(BGPNotification.Error.CEASE.getCode());
try {
otherSession.sendNotification(notification);
} catch(IOException ex) {
}
sessions.remove(otherSession);
otherSession.dropConnection();
otherSession.cleanup();
// Accept new connection
return false;
} else {
// Close new connection
sessions.remove(session);
return true;
}
}
return false;
}
public void run() {
while (true) {
try {
Socket socket = serverSocket.accept();
System.out.println("Accept");
BGPSessionConfiguration config = sessionConfigurations.stream()
.filter(c -> socket.getInetAddress().equals(c.getRemoteAddr()))
.findFirst()
.orElse(null);
System.out.println("Config: " + config);
if(config == null) {
System.out.println("Peer not found:" + socket.getInetAddress());
socket.close();
continue;
}
BGPSession session = new BGPSession(this, socket, config);
sessions.add(session);
session.getFsm().getCurrentState().automaticStartPassive();
// System.out.println("tcpConnectionConfirmed in " + fsm.getCurrentState());
// fsm.getCurrentState().tcpConnectionConfirmed();
} catch (IOException ex) {
if (serverSocket.isClosed())
break;
ex.printStackTrace();
}
}
}
public boolean connect(BGPSessionConfiguration config, String host) {
return connect(config, host, 179);
}
public boolean connect(BGPSessionConfiguration config, String host, int port) {
for (BGPSession session : sessions) {
if (session.getConfiguration().equals(config)) {
// Already connected
return false;
}
}
BGPSession session = new BGPSession(this, config, host, port);
sessions.add(session);
session.getFsm().getCurrentState().automaticStart();
return true;
}
public void shutdown() {
for(BGPSession session : sessions) {
session.automaticStop();
session.cleanup();
}
sessions.clear();
if (serverSocket != null) {
try {
serverSocket.close();
} catch(IOException ex) {
ex.printStackTrace();
}
}
}
}
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