org.punksearch.logic.online.Probe.java Source code

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Here is the source code for org.punksearch.logic.online.Probe.java

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/***************************************************************************
 *                                                                         *
 *   PunkSearch - Searching over LAN                                       *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
package org.punksearch.logic.online;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;

import static org.punksearch.common.Settings.get;
import static org.punksearch.common.Settings.getInt;

/**
 * Probes if some particular host is online. Both SMB and FTP protocols are supported.
 * <p/>
 * Use connect() method to test any required port for a host.
 * <p/>
 * Use ping() method to ping the host (does not open a connection).
 * <p/>
 * Use probe() method to use default strategy (can be adjusted with system property)
 *
 * @author Yury Soldak (ysoldak@gmail.com)
 */
public class Probe {
    private static Log log = LogFactory.getLog(Probe.class);

    /**
     * Count of msec to wait while probing host's port. <p/> Host considered offline if socket was not opened in this
     * period of time.
     */
    public static final String TIMEOUT_PROPERTY = "org.punksearch.online.timeout";

    /**
     * Strategy to use for determining host status: "ping" or "connect" ("connect" is used by default)
     * <p/>
     * First does not open connection to remote host, but inaccurate (it does not prove smb/ftp server is running).
     * <p/>
     * Second opens connection to remote host and closes it immediately, yet remote host observes connection, etc.
     */
    public static final String STRATEGY_PROPERTY = "org.punksearch.online.strategy";

    private static int PROBE_TIMEOUT = getInt(TIMEOUT_PROPERTY, 1000);
    private static String PROBE_STRATEGY = get(STRATEGY_PROPERTY, "connect");

    private static final boolean USE_OLD_SMB_PORT = true;

    private static final int SMB_PORT = 445;
    private static final int SMB_OLD_PORT = 139;
    private static final int FTP_PORT = 21;

    /**
     * Does probing. Expects host in form [protocol]://[ip]
     *
     * @param host Host to probe
     * @return true if online, false if offline
     */
    public boolean probe(String host) {
        String ip = host.substring(6); // strip "smb://" or "ftp://"
        if (PROBE_STRATEGY.equals("ping")) {
            return ping(ip);
        } else {
            return (host.startsWith("ftp")) ? connectFtp(ip) : connectSmb(ip);
        }
    }

    public boolean ping(String ip) {
        boolean result;
        try {
            InetAddress ia = InetAddress.getByName(ip);
            result = ia.isReachable(PROBE_TIMEOUT);
        } catch (Exception e) {
            log.warn("Exception during ping: " + e.getMessage());
            result = false;
        }
        log.debug("Probe (ping): " + ip + " = " + result);
        return result;
    }

    private boolean connectSmb(String ip) {
        return connect(ip, SMB_PORT) || (USE_OLD_SMB_PORT && connect(ip, SMB_OLD_PORT));
    }

    private boolean connectFtp(String ip) {
        return connect(ip, FTP_PORT);
    }

    /**
     * Checks if custom port is open at the host
     *
     * @param ip   IP of the host to check
     * @param port Port of the host to check
     * @return true if port is open, false if closed
     */
    public boolean connect(String ip, int port) {
        boolean result;
        try {
            SocketAddress sockaddr = new InetSocketAddress(ip, port);
            Socket s = new Socket();
            s.connect(sockaddr, PROBE_TIMEOUT);
            s.close();
            result = true;
        } catch (IOException e) {
            log.trace(ip + ":" + port + " -> " + e);
            result = false;
        }
        log.debug("Probe (connect): " + ip + ":" + port + " = " + result);
        return result;
    }
}