public void execute()

in core/src/main/java/org/apache/ftpserver/command/impl/PORT.java [67:143]
65 lines of code
10 McCabe index (conditional complexity)

    public void execute(final FtpIoSession session,
            final FtpServerContext context, final FtpRequest request)
            throws IOException {

        // reset state variables
        session.resetState();

        // argument check
        if (!request.hasArgument()) {
            session.write(LocalizedFtpReply.translate(session, request, context,
                    FtpReply.REPLY_501_SYNTAX_ERROR_IN_PARAMETERS_OR_ARGUMENTS,
                    "PORT", null));
            return;
        }

        // is port enabled
        DataConnectionConfiguration dataCfg = session.getListener()
                .getDataConnectionConfiguration();
        if (!dataCfg.isActiveEnabled()) {
            session.write(LocalizedFtpReply.translate(session, request, context,
                    FtpReply.REPLY_501_SYNTAX_ERROR_IN_PARAMETERS_OR_ARGUMENTS, "PORT.disabled", null));
            return;
        }

        InetSocketAddress address;
        try {
            address = SocketAddressEncoder.decode(request.getArgument());
            
            // port must not be 0
            if(address.getPort() == 0) {
                throw new IllegalPortException("PORT port must not be 0");
            }
        } catch (IllegalInetAddressException e) {
            session.write(LocalizedFtpReply.translate(session, request, context,
                    FtpReply.REPLY_501_SYNTAX_ERROR_IN_PARAMETERS_OR_ARGUMENTS, "PORT", null));
            return;
        } catch (IllegalPortException e) {
            LOG.debug("Invalid data port: " + request.getArgument(), e);
            session
                    .write(LocalizedFtpReply
                            .translate(
                                    session,
                                    request,
                                    context,
                                    FtpReply.REPLY_501_SYNTAX_ERROR_IN_PARAMETERS_OR_ARGUMENTS,
                                    "PORT.invalid", null));
            return;
        } catch (UnknownHostException e) {
            LOG.debug("Unknown host", e);
            session
                    .write(LocalizedFtpReply
                            .translate(
                                    session,
                                    request,
                                    context,
                                    FtpReply.REPLY_501_SYNTAX_ERROR_IN_PARAMETERS_OR_ARGUMENTS,
                                    "PORT.host", null));
            return;
        }

        // check IP
        if (dataCfg.isActiveIpCheck()) {
            if (session.getRemoteAddress() instanceof InetSocketAddress) {
                InetAddress clientAddr = ((InetSocketAddress) session
                        .getRemoteAddress()).getAddress();
                if (!address.getAddress().equals(clientAddr)) {
                    session.write(LocalizedFtpReply.translate(session, request,
                            context, FtpReply.REPLY_501_SYNTAX_ERROR_IN_PARAMETERS_OR_ARGUMENTS, "PORT.mismatch", null));
                    return;
                }
            }
        }

        session.getDataConnection().initActiveDataConnection(address);
        session.write(LocalizedFtpReply.translate(session, request, context,
                FtpReply.REPLY_200_COMMAND_OKAY, "PORT", null));
    }