LinuxEphemeralPortRangeDetector.java

// Licensed to the Software Freedom Conservancy (SFC) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The SFC licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

package org.jboss.arquillian.warp.impl.utils.net;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;

public class LinuxEphemeralPortRangeDetector
    implements EphemeralPortRangeDetector {

    final int firstEphemeralPort;
    final int lastEphemeralPort;

    public static LinuxEphemeralPortRangeDetector getInstance() {
        File file = new File("/proc/sys/net/ipv4/ip_local_port_range");
        if (file.exists() && file.canRead()) {
            Reader inputFil = null;
            try {
                inputFil = new FileReader(file);
            } catch (FileNotFoundException e) {
                throw new RuntimeException(e);
            }
            return new LinuxEphemeralPortRangeDetector(inputFil);
        }
        return new LinuxEphemeralPortRangeDetector(new StringReader("49152 65535"));
    }

    LinuxEphemeralPortRangeDetector(Reader inputFil) {
        FixedIANAPortRange defaultRange = new FixedIANAPortRange();
        int lowPort = defaultRange.getLowestEphemeralPort();
        int highPort = defaultRange.getHighestEphemeralPort();
        try {
            BufferedReader in = new BufferedReader(inputFil);
            final String s;
            s = in.readLine();
            final String[] split = s.split("\\s");
            lowPort = Integer.parseInt(split[0]);
            highPort = Integer.parseInt(split[1]);
        } catch (IOException ignore) {
        }
        firstEphemeralPort = lowPort;
        lastEphemeralPort = highPort;
    }

    public int getLowestEphemeralPort() {
        return firstEphemeralPort;
    }

    public int getHighestEphemeralPort() {
        return lastEphemeralPort;
    }
}