1 /*
   2  * Copyright (c) 2013, 2020, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <unistd.h>
  29 #include <errno.h>
  30 
  31 #if defined(_ALLBSD_SOURCE)
  32 #include <sys/sysctl.h>
  33 #endif
  34 
  35 #include "jni.h"
  36 #include "net_util.h"
  37 #include "sun_net_PortConfig.h"
  38 
  39 #ifdef __cplusplus
  40 extern "C" {
  41 #endif
  42 
  43 struct portrange {
  44     int lower;
  45     int higher;
  46 };
  47 
  48 static int getPortRange(struct portrange *range)
  49 {
  50 #ifdef __linux__
  51     {
  52         FILE *f;
  53         int ret;
  54 
  55         f = fopen("/proc/sys/net/ipv4/ip_local_port_range", "r");
  56         if (f != NULL) {
  57             ret = fscanf(f, "%d %d", &range->lower, &range->higher);
  58             fclose(f);
  59             return ret == 2 ? 0 : -1;
  60         }
  61         return -1;
  62     }
  63 #elif defined(_ALLBSD_SOURCE)
  64     {
  65         int ret;
  66         size_t size = sizeof(range->lower);
  67         ret = sysctlbyname(
  68             "net.inet.ip.portrange.first", &range->lower, &size, 0, 0
  69         );
  70         if (ret == -1) {
  71             return -1;
  72         }
  73         size = sizeof(range->higher);
  74         ret = sysctlbyname(
  75             "net.inet.ip.portrange.last", &range->higher, &size, 0, 0
  76         );
  77         return ret;
  78     }
  79 #else
  80     return -1;
  81 #endif
  82 }
  83 
  84 /*
  85  * Class:     sun_net_PortConfig
  86  * Method:    getLower0
  87  * Signature: ()I
  88  */
  89 JNIEXPORT jint JNICALL Java_sun_net_PortConfig_getLower0
  90   (JNIEnv *env, jclass clazz)
  91 {
  92     struct portrange range;
  93     if (getPortRange(&range) < 0) {
  94         return -1;
  95     }
  96     return range.lower;
  97 }
  98 
  99 /*
 100  * Class:     sun_net_PortConfig
 101  * Method:    getUpper0
 102  * Signature: ()I
 103  */
 104 JNIEXPORT jint JNICALL Java_sun_net_PortConfig_getUpper0
 105   (JNIEnv *env, jclass clazz)
 106 {
 107     struct portrange range;
 108     if (getPortRange(&range) < 0) {
 109         return -1;
 110     }
 111     return range.higher;
 112 }
 113 
 114 #ifdef __cplusplus
 115 }
 116 #endif