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Java example source code file (NetworkInterface.c)

This example Java source code file (NetworkInterface.c) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

check_null, dword, getiftable, jni_false, jnicall, jnienv, jniexport, jnu_throwoutofmemoryerror, mib_ifrow, mib_iftable, mib_ipaddrtable, native, null, true

The NetworkInterface.c Java example source code

/*
 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

#include <stdlib.h>
#include <windows.h>
#include <winsock2.h>           /* needed for htonl */
#include <iprtrmib.h>
#include <assert.h>

#include "java_net_NetworkInterface.h"
#include "jni_util.h"

#include "NetworkInterface.h"

/*
 * Windows implementation of the java.net.NetworkInterface native methods.
 * This module provides the implementations of getAll, getByName, getByIndex,
 * and getByAddress.
 *
 * Interfaces and addresses are enumerated using the IP helper routines
 * GetIfTable, GetIfAddrTable resp. These routines are available on Windows
 * 98, NT SP+4, 2000, and XP. They are also available on Windows 95 if
 * IE is upgraded to 5.x.
 *
 * Windows does not have any standard for device names so we are forced
 * to use our own convention which is based on the normal Unix naming
 * convention ("lo" for the loopback, eth0, eth1, .. for ethernet devices,
 * tr0, tr1, .. for token ring, and so on). This convention gives us
 * consistency across multiple Windows editions and also consistency with
 * Solaris/Linux device names. Note that we always enumerate in index
 * order and this ensures consistent device number across invocations.
 */

/* various JNI ids */

jclass ni_class;            /* NetworkInterface */

jmethodID ni_ctor;          /* NetworkInterface() */

jfieldID ni_indexID;        /* NetworkInterface.index */
jfieldID ni_addrsID;        /* NetworkInterface.addrs */
jfieldID ni_bindsID;        /* NetworkInterface.bindings */
jfieldID ni_nameID;         /* NetworkInterface.name */
jfieldID ni_displayNameID;  /* NetworkInterface.displayName */
jfieldID ni_childsID;       /* NetworkInterface.childs */
jclass ni_iacls;            /* InetAddress */

jclass ni_ia4cls;           /* Inet4Address */
jmethodID ni_ia4Ctor;       /* Inet4Address() */

jclass ni_ia6cls;           /* Inet6Address */
jmethodID ni_ia6ctrID;      /* Inet6Address() */

jclass ni_ibcls;            /* InterfaceAddress */
jmethodID ni_ibctrID;       /* InterfaceAddress() */
jfieldID ni_ibaddressID;        /* InterfaceAddress.address */
jfieldID ni_ibbroadcastID;      /* InterfaceAddress.broadcast */
jfieldID ni_ibmaskID;           /* InterfaceAddress.maskLength */

/*
 * Support routines to free netif and netaddr lists
 */
void free_netif(netif *netifP) {
    netif *curr = netifP;
    while (curr != NULL) {
        if (curr->name != NULL)
            free(curr->name);
        if (curr->displayName != NULL)
            free(curr->displayName);
        if (curr->addrs != NULL)
            free_netaddr (curr->addrs);
        netifP = netifP->next;
        free(curr);
        curr = netifP;
    }
}

void free_netaddr(netaddr *netaddrP) {
    netaddr *curr = netaddrP;
    while (curr != NULL) {
        netaddrP = netaddrP->next;
        free(curr);
        curr = netaddrP;
    }
}

/*
 * Returns the interface structure from the table with the matching index.
 */
MIB_IFROW *getIF(jint index) {
    MIB_IFTABLE *tableP;
    MIB_IFROW *ifrowP, *ret = NULL;
    ULONG size;
    DWORD i, count;
    jint ifindex;

    /*
     * Ask the IP Helper library to enumerate the adapters
     */
    size = sizeof(MIB_IFTABLE);
    tableP = (MIB_IFTABLE *)malloc(size);
    if(tableP == NULL)
        return NULL;

    count = GetIfTable(tableP, &size, TRUE);
    if (count == ERROR_INSUFFICIENT_BUFFER || count == ERROR_BUFFER_OVERFLOW) {
        MIB_IFTABLE* newTableP =  (MIB_IFTABLE *)realloc(tableP, size);
        if (newTableP == NULL) {
            free(tableP);
            return NULL;
        }
        tableP = newTableP;

        count = GetIfTable(tableP, &size, TRUE);
    }

    if (count != NO_ERROR) {
        free(tableP);
        return NULL;
    }

    {
    ifrowP = tableP->table;
    for (i=0; i<tableP->dwNumEntries; i++) {
    /*
     * Warning: the real index is obtained by GetFriendlyIfIndex()
    */
        ifindex = GetFriendlyIfIndex(ifrowP->dwIndex);
        if (ifindex == index) {
          /*
           * Create a copy of the entry so that we can free the table.
           */
            ret = (MIB_IFROW *) malloc(sizeof(MIB_IFROW));
            if (ret == NULL) {
                free(tableP);
                return NULL;
            }
            memcpy(ret, ifrowP, sizeof(MIB_IFROW));
            break;
        }

        /* onto the next interface */
        ifrowP++;
      }
      free(tableP);
    }
    return ret;
}

/*
 * Enumerate network interfaces using IP Helper Library routine GetIfTable.
 * We use GetIfTable rather than other IP helper routines because it's
 * available on 98 & NT SP4+.
 *
 * Returns the number of interfaces found or -1 if error. If no error
 * occurs then netifPP be returned as list of netif structures or NULL
 * if no interfaces are found.
 */
int enumInterfaces(JNIEnv *env, netif **netifPP)
{
    MIB_IFTABLE *tableP;
    MIB_IFROW *ifrowP;
    ULONG size;
    DWORD ret;
    int count;
    netif *netifP;
    DWORD i;
    int lo=0, eth=0, tr=0, fddi=0, ppp=0, sl=0, wlan=0, net=0, wlen=0;

    /*
     * Ask the IP Helper library to enumerate the adapters
     */
    size = sizeof(MIB_IFTABLE);
    tableP = (MIB_IFTABLE *)malloc(size);
    if (tableP == NULL) {
        JNU_ThrowOutOfMemoryError(env, "Native heap allocation failure");
        return -1;
    }

    ret = GetIfTable(tableP, &size, TRUE);
    if (ret == ERROR_INSUFFICIENT_BUFFER || ret == ERROR_BUFFER_OVERFLOW) {
        MIB_IFTABLE * newTableP = (MIB_IFTABLE *)realloc(tableP, size);
        if (newTableP == NULL) {
            free(tableP);
            JNU_ThrowOutOfMemoryError(env, "Native heap allocation failure");
            return -1;
        }
        tableP = newTableP;
        ret = GetIfTable(tableP, &size, TRUE);
    }

    if (ret != NO_ERROR) {
        free(tableP);

        JNU_ThrowByName(env, "java/lang/Error",
                "IP Helper Library GetIfTable function failed");

        return -1;
    }

    /*
     * Iterate through the list of adapters
     */
    count = 0;
    netifP = NULL;

    ifrowP = tableP->table;
    for (i=0; i<tableP->dwNumEntries; i++) {
        char dev_name[8];
        netif *curr;

        /*
         * Generate a name for the device as Windows doesn't have any
         * real concept of a device name.
         */
        switch (ifrowP->dwType) {
            case MIB_IF_TYPE_ETHERNET:
                _snprintf_s(dev_name, 8, _TRUNCATE, "eth%d", eth++);
                break;

            case MIB_IF_TYPE_TOKENRING:
                _snprintf_s(dev_name, 8, _TRUNCATE, "tr%d", tr++);
                break;

            case MIB_IF_TYPE_FDDI:
                _snprintf_s(dev_name, 8, _TRUNCATE, "fddi%d", fddi++);
                break;

            case MIB_IF_TYPE_LOOPBACK:
                /* There should only be only IPv4 loopback address */
                if (lo > 0) {
                    continue;
                }
                strncpy_s(dev_name, 8, "lo", _TRUNCATE);
                lo++;
                break;

            case MIB_IF_TYPE_PPP:
                _snprintf_s(dev_name, 8, _TRUNCATE, "ppp%d", ppp++);
                break;

            case MIB_IF_TYPE_SLIP:
                _snprintf_s(dev_name, 8, _TRUNCATE, "sl%d", sl++);
                break;

            case IF_TYPE_IEEE80211:
                _snprintf_s(dev_name, 8, _TRUNCATE, "wlan%d", wlan++);
                break;

            default:
                _snprintf_s(dev_name, 8, _TRUNCATE, "net%d", net++);
        }

        /*
         * Allocate a netif structure and space for the name and
         * display name (description in this case).
         */
        curr = (netif *)calloc(1, sizeof(netif));
        if (curr != NULL) {
            wlen = MultiByteToWideChar(CP_OEMCP, 0, ifrowP->bDescr,
                       ifrowP->dwDescrLen, NULL, 0);
            if(wlen == 0) {
                // MultiByteToWideChar should not fail
                // But in rare case it fails, we allow 'char' to be displayed
                curr->displayName = (char *)malloc(ifrowP->dwDescrLen + 1);
            } else {
                curr->displayName = (wchar_t *)malloc(wlen*(sizeof(wchar_t))+1);
            }

            curr->name = (char *)malloc(strlen(dev_name) + 1);

            if (curr->name == NULL || curr->displayName == NULL) {
                if (curr->name) free(curr->name);
                if (curr->displayName) free(curr->displayName);
                curr = NULL;
            }
        }
        if (curr == NULL) {
            JNU_ThrowOutOfMemoryError(env, "Native heap allocation failure");
            free_netif(netifP);
            free(tableP);
            return -1;
        }

        /*
         * Populate the interface. Note that we need to convert the
         * index into its "friendly" value as otherwise we will expose
         * 32-bit numbers as index values.
         */
        strcpy(curr->name, dev_name);
        if (wlen == 0) {
            // display char type in case of MultiByteToWideChar failure
            strncpy(curr->displayName, ifrowP->bDescr, ifrowP->dwDescrLen);
            curr->displayName[ifrowP->dwDescrLen] = '\0';
        } else {
            // call MultiByteToWideChar again to fill curr->displayName
            // it should not fail, because we have called it once before
            if (MultiByteToWideChar(CP_OEMCP, 0, ifrowP->bDescr,
                   ifrowP->dwDescrLen, curr->displayName, wlen) == 0) {
                JNU_ThrowByName(env, "java/lang/Error",
                       "Cannot get multibyte char for interface display name");
                free_netif(netifP);
                free(tableP);
                free(curr->name);
                free(curr->displayName);
                free(curr);
                return -1;
            } else {
                curr->displayName[wlen*(sizeof(wchar_t))] = '\0';
                curr->dNameIsUnicode = TRUE;
            }
        }

        curr->dwIndex = ifrowP->dwIndex;
        curr->ifType = ifrowP->dwType;
        curr->index = GetFriendlyIfIndex(ifrowP->dwIndex);

        /*
         * Put the interface at tail of list as GetIfTable(,,TRUE) is
         * returning the interfaces in index order.
         */
        count++;
        if (netifP == NULL) {
            netifP = curr;
        } else {
            netif *tail = netifP;
            while (tail->next != NULL) {
                tail = tail->next;
            }
            tail->next = curr;
        }

        /* onto the next interface */
        ifrowP++;
    }

    /*
     * Free the interface table and return the interface list
     */
    if (tableP) {
        free(tableP);
    }
    *netifPP = netifP;
    return count;
}

/*
 * Enumerate the IP addresses on an interface using the IP helper library
 * routine GetIfAddrTable and matching based on the index name. There are
 * more efficient routines but we use GetIfAddrTable because it's avaliable
 * on 98 and NT.
 *
 * Returns the count of addresses, or -1 if error. If no error occurs then
 * netaddrPP will return a list of netaddr structures with the IP addresses.
 */
int enumAddresses_win(JNIEnv *env, netif *netifP, netaddr **netaddrPP)
{
    MIB_IPADDRTABLE *tableP;
    ULONG size;
    DWORD ret;
    DWORD i;
    netaddr *netaddrP;
    int count = 0;
    unsigned long mask;

    /*
     * Use GetIpAddrTable to enumerate the IP Addresses
     */
    size = sizeof(MIB_IPADDRTABLE);
    tableP = (MIB_IPADDRTABLE *)malloc(size);
    if (tableP == NULL) {
        JNU_ThrowOutOfMemoryError(env, "Native heap allocation failure");
        return -1;
    }

    ret = GetIpAddrTable(tableP, &size, FALSE);
    if (ret == ERROR_INSUFFICIENT_BUFFER || ret == ERROR_BUFFER_OVERFLOW) {
        MIB_IPADDRTABLE * newTableP = (MIB_IPADDRTABLE *)realloc(tableP, size);
        if (newTableP == NULL) {
            free(tableP);
            JNU_ThrowOutOfMemoryError(env, "Native heap allocation failure");
            return -1;
        }
        tableP = newTableP;

        ret = GetIpAddrTable(tableP, &size, FALSE);
    }
    if (ret != NO_ERROR) {
        if (tableP) {
            free(tableP);
        }
        JNU_ThrowByName(env, "java/lang/Error",
                "IP Helper Library GetIpAddrTable function failed");
        return -1;
    }

    /*
     * Iterate through the table to find the addresses with the
     * matching dwIndex. Ignore 0.0.0.0 addresses.
     */
    count = 0;
    netaddrP = NULL;

    i = 0;
    while (i<tableP->dwNumEntries) {
        if (tableP->table[i].dwIndex == netifP->dwIndex &&
            tableP->table[i].dwAddr != 0) {

            netaddr *curr = (netaddr *)malloc(sizeof(netaddr));
            if (curr == NULL) {
                JNU_ThrowOutOfMemoryError(env, "Native heap allocation failure");
                free_netaddr(netaddrP);
                free(tableP);
                return -1;
            }

            curr->addr.him4.sin_family = AF_INET;
            curr->addr.him4.sin_addr.s_addr = tableP->table[i].dwAddr;
            /*
             * Get netmask / broadcast address
             */
            switch (netifP->ifType) {
            case MIB_IF_TYPE_ETHERNET:
            case MIB_IF_TYPE_TOKENRING:
            case MIB_IF_TYPE_FDDI:
            case MIB_IF_TYPE_LOOPBACK:
            case IF_TYPE_IEEE80211:
              /**
               * Contrary to what it seems to indicate, dwBCastAddr doesn't
               * contain the broadcast address but 0 or 1 depending on whether
               * the broadcast address should set the bits of the host part
               * to 0 or 1.
               * Yes, I know it's stupid, but what can I say, it's MSFTs API.
               */
              curr->brdcast.him4.sin_family = AF_INET;
              if (tableP->table[i].dwBCastAddr == 1)
                curr->brdcast.him4.sin_addr.s_addr = (tableP->table[i].dwAddr & tableP->table[i].dwMask) | (0xffffffff ^ tableP->table[i].dwMask);
              else
                curr->brdcast.him4.sin_addr.s_addr = (tableP->table[i].dwAddr & tableP->table[i].dwMask);
              mask = ntohl(tableP->table[i].dwMask);
              curr->mask = 0;
              while (mask) {
                mask <<= 1;
                curr->mask++;
              }
              break;
            case MIB_IF_TYPE_PPP:
            case MIB_IF_TYPE_SLIP:
            default:
              /**
               * these don't have broadcast/subnet
               */
              curr->mask = -1;
                break;
            }

            curr->next = netaddrP;
            netaddrP = curr;
            count++;
        }
        i++;
    }

    *netaddrPP = netaddrP;
    free(tableP);
    return count;
}

/*
 * Class:     java_net_NetworkInterface
 * Method:    init
 * Signature: ()V
 */
JNIEXPORT void JNICALL
Java_java_net_NetworkInterface_init(JNIEnv *env, jclass cls)
{
    /*
     * Get the various JNI ids that we require
     */
    ni_class = (*env)->NewGlobalRef(env, cls);
    CHECK_NULL(ni_class);
    ni_nameID = (*env)->GetFieldID(env, ni_class, "name", "Ljava/lang/String;");
    CHECK_NULL(ni_nameID);
    ni_displayNameID = (*env)->GetFieldID(env, ni_class, "displayName", "Ljava/lang/String;");
    CHECK_NULL(ni_displayNameID);
    ni_indexID = (*env)->GetFieldID(env, ni_class, "index", "I");
    CHECK_NULL(ni_indexID);
    ni_addrsID = (*env)->GetFieldID(env, ni_class, "addrs", "[Ljava/net/InetAddress;");
    CHECK_NULL(ni_addrsID);
    ni_bindsID = (*env)->GetFieldID(env, ni_class, "bindings", "[Ljava/net/InterfaceAddress;");
    CHECK_NULL(ni_bindsID);
    ni_childsID = (*env)->GetFieldID(env, ni_class, "childs", "[Ljava/net/NetworkInterface;");
    CHECK_NULL(ni_childsID);
    ni_ctor = (*env)->GetMethodID(env, ni_class, "<init>", "()V");
    CHECK_NULL(ni_ctor);

    ni_iacls = (*env)->FindClass(env, "java/net/InetAddress");
    CHECK_NULL(ni_iacls);
    ni_iacls = (*env)->NewGlobalRef(env, ni_iacls);
    CHECK_NULL(ni_iacls);

    ni_ia4cls = (*env)->FindClass(env, "java/net/Inet4Address");
    CHECK_NULL(ni_ia4cls);
    ni_ia4cls = (*env)->NewGlobalRef(env, ni_ia4cls);
    CHECK_NULL(ni_ia4cls);
    ni_ia4Ctor = (*env)->GetMethodID(env, ni_ia4cls, "<init>", "()V");
    CHECK_NULL(ni_ia4Ctor);

    ni_ia6cls = (*env)->FindClass(env, "java/net/Inet6Address");
    CHECK_NULL(ni_ia6cls);
    ni_ia6cls = (*env)->NewGlobalRef(env, ni_ia6cls);
    CHECK_NULL(ni_ia6cls);
    ni_ia6ctrID = (*env)->GetMethodID(env, ni_ia6cls, "<init>", "()V");
    CHECK_NULL(ni_ia6ctrID);

    ni_ibcls = (*env)->FindClass(env, "java/net/InterfaceAddress");
    CHECK_NULL(ni_ibcls);
    ni_ibcls = (*env)->NewGlobalRef(env, ni_ibcls);
    CHECK_NULL(ni_ibcls);
    ni_ibctrID = (*env)->GetMethodID(env, ni_ibcls, "<init>", "()V");
    CHECK_NULL(ni_ibctrID);
    ni_ibaddressID = (*env)->GetFieldID(env, ni_ibcls, "address", "Ljava/net/InetAddress;");
    CHECK_NULL(ni_ibaddressID);
    ni_ibbroadcastID = (*env)->GetFieldID(env, ni_ibcls, "broadcast", "Ljava/net/Inet4Address;");
    CHECK_NULL(ni_ibbroadcastID);
    ni_ibmaskID = (*env)->GetFieldID(env, ni_ibcls, "maskLength", "S");
}

/*
 * Create a NetworkInterface object, populate the name and index, and
 * populate the InetAddress array based on the IP addresses for this
 * interface.
 */
jobject createNetworkInterface
    (JNIEnv *env, netif *ifs, int netaddrCount, netaddr *netaddrP)
{
    jobject netifObj;
    jobject name, displayName;
    jobjectArray addrArr, bindsArr, childArr;
    netaddr *addrs;
    jint addr_index;
    jint bind_index;

    /*
     * Create a NetworkInterface object and populate it
     */
    netifObj = (*env)->NewObject(env, ni_class, ni_ctor);
    name = (*env)->NewStringUTF(env, ifs->name);
    if (ifs->dNameIsUnicode) {
        displayName = (*env)->NewString(env, (PWCHAR)ifs->displayName,
                                       (jsize)wcslen ((PWCHAR)ifs->displayName));
    } else {
        displayName = (*env)->NewStringUTF(env, ifs->displayName);
    }
    if (netifObj == NULL || name == NULL || displayName == NULL) {
        return NULL;
    }
    (*env)->SetObjectField(env, netifObj, ni_nameID, name);
    (*env)->SetObjectField(env, netifObj, ni_displayNameID, displayName);
    (*env)->SetIntField(env, netifObj, ni_indexID, ifs->index);

    /*
     * Get the IP addresses for this interface if necessary
     * Note that 0 is a valid number of addresses.
     */
    if (netaddrCount < 0) {
        netaddrCount = enumAddresses_win(env, ifs, &netaddrP);
        if (netaddrCount == -1) {
            return NULL;
        }
    }
    addrArr = (*env)->NewObjectArray(env, netaddrCount, ni_iacls, NULL);
    if (addrArr == NULL) {
        free_netaddr(netaddrP);
        return NULL;
    }

    bindsArr = (*env)->NewObjectArray(env, netaddrCount, ni_ibcls, NULL);
    if (bindsArr == NULL) {
      free_netaddr(netaddrP);
      return NULL;
    }
    addrs = netaddrP;
    addr_index = 0;
    bind_index = 0;
    while (addrs != NULL) {
        jobject iaObj, ia2Obj;
        jobject ibObj = NULL;
        if (addrs->addr.him.sa_family == AF_INET) {
            iaObj = (*env)->NewObject(env, ni_ia4cls, ni_ia4Ctor);
            if (iaObj == NULL) {
                free_netaddr(netaddrP);
                return NULL;
            }
            /* default ctor will set family to AF_INET */

            setInetAddress_addr(env, iaObj, ntohl(addrs->addr.him4.sin_addr.s_addr));
            if (addrs->mask != -1) {
              ibObj = (*env)->NewObject(env, ni_ibcls, ni_ibctrID);
              if (ibObj == NULL) {
                free_netaddr(netaddrP);
                return NULL;
              }
              (*env)->SetObjectField(env, ibObj, ni_ibaddressID, iaObj);
              ia2Obj = (*env)->NewObject(env, ni_ia4cls, ni_ia4Ctor);
              if (ia2Obj == NULL) {
                free_netaddr(netaddrP);
                return NULL;
              }
              setInetAddress_addr(env, ia2Obj, ntohl(addrs->brdcast.him4.sin_addr.s_addr));
              (*env)->SetObjectField(env, ibObj, ni_ibbroadcastID, ia2Obj);
              (*env)->SetShortField(env, ibObj, ni_ibmaskID, addrs->mask);
              (*env)->SetObjectArrayElement(env, bindsArr, bind_index++, ibObj);
            }
        } else /* AF_INET6 */ {
            int scope;
            iaObj = (*env)->NewObject(env, ni_ia6cls, ni_ia6ctrID);
            if (iaObj) {
                int ret = setInet6Address_ipaddress(env, iaObj,  (jbyte *)&(addrs->addr.him6.sin6_addr.s6_addr));
                if (ret == JNI_FALSE) {
                    return NULL;
                }

                scope = addrs->addr.him6.sin6_scope_id;
                if (scope != 0) { /* zero is default value, no need to set */
                    setInet6Address_scopeid(env, iaObj, scope);
                    setInet6Address_scopeifname(env, iaObj, netifObj);
                }
                ibObj = (*env)->NewObject(env, ni_ibcls, ni_ibctrID);
                if (ibObj == NULL) {
                  free_netaddr(netaddrP);
                  return NULL;
                }
                (*env)->SetObjectField(env, ibObj, ni_ibaddressID, iaObj);
                (*env)->SetShortField(env, ibObj, ni_ibmaskID, addrs->mask);
                (*env)->SetObjectArrayElement(env, bindsArr, bind_index++, ibObj);
            }
        }
        (*env)->SetObjectArrayElement(env, addrArr, addr_index, iaObj);
        addrs = addrs->next;
        addr_index++;
    }
    (*env)->SetObjectField(env, netifObj, ni_addrsID, addrArr);
    (*env)->SetObjectField(env, netifObj, ni_bindsID, bindsArr);

    free_netaddr(netaddrP);

    /*
     * Windows doesn't have virtual interfaces, so child array
     * is always empty.
     */
    childArr = (*env)->NewObjectArray(env, 0, ni_class, NULL);
    if (childArr == NULL) {
      return NULL;
    }
    (*env)->SetObjectField(env, netifObj, ni_childsID, childArr);

    /* return the NetworkInterface */
    return netifObj;
}

/*
 * Class:     java_net_NetworkInterface
 * Method:    getByName0
 * Signature: (Ljava/lang/String;)Ljava/net/NetworkInterface;
 */
JNIEXPORT jobject JNICALL Java_java_net_NetworkInterface_getByName0
    (JNIEnv *env, jclass cls, jstring name)
{
    netif *ifList, *curr;
    jboolean isCopy;
    const char *name_utf;
    jobject netifObj = NULL;

    // Retained for now to support IPv4 only stack, java.net.preferIPv4Stack
    if (ipv6_available()) {
        return Java_java_net_NetworkInterface_getByName0_XP (env, cls, name);
    }

    /* get the list of interfaces */
    if (enumInterfaces(env, &ifList) < 0) {
        return NULL;
    }

    /* get the name as a C string */
    name_utf = (*env)->GetStringUTFChars(env, name, &isCopy);

    /* Search by name */
    curr = ifList;
    while (curr != NULL) {
        if (strcmp(name_utf, curr->name) == 0) {
            break;
        }
        curr = curr->next;
    }

    /* if found create a NetworkInterface */
    if (curr != NULL) {;
        netifObj = createNetworkInterface(env, curr, -1, NULL);
    }

    /* release the UTF string */
    (*env)->ReleaseStringUTFChars(env, name, name_utf);

    /* release the interface list */
    free_netif(ifList);

    return netifObj;
}

/*
 * Class:     NetworkInterface
 * Method:    getByIndex0
 * Signature: (I)LNetworkInterface;
 */
JNIEXPORT jobject JNICALL Java_java_net_NetworkInterface_getByIndex0
  (JNIEnv *env, jclass cls, jint index)
{
    netif *ifList, *curr;
    jobject netifObj = NULL;

    // Retained for now to support IPv4 only stack, java.net.preferIPv4Stack
    if (ipv6_available()) {
        return Java_java_net_NetworkInterface_getByIndex0_XP (env, cls, index);
    }

    /* get the list of interfaces */
    if (enumInterfaces(env, &ifList) < 0) {
        return NULL;
    }

    /* search by index */
    curr = ifList;
    while (curr != NULL) {
        if (index == curr->index) {
            break;
        }
        curr = curr->next;
    }

    /* if found create a NetworkInterface */
    if (curr != NULL) {
        netifObj = createNetworkInterface(env, curr, -1, NULL);
    }

    /* release the interface list */
    free_netif(ifList);

    return netifObj;
}

/*
 * Class:     java_net_NetworkInterface
 * Method:    getByInetAddress0
 * Signature: (Ljava/net/InetAddress;)Ljava/net/NetworkInterface;
 */
JNIEXPORT jobject JNICALL Java_java_net_NetworkInterface_getByInetAddress0
    (JNIEnv *env, jclass cls, jobject iaObj)
{
    netif *ifList, *curr;
    jint addr = getInetAddress_addr(env, iaObj);
    jobject netifObj = NULL;

    // Retained for now to support IPv4 only stack, java.net.preferIPv4Stack
    if (ipv6_available()) {
        return Java_java_net_NetworkInterface_getByInetAddress0_XP (env, cls, iaObj);
    }

    /* get the list of interfaces */
    if (enumInterfaces(env, &ifList) < 0) {
        return NULL;
    }

    /*
     * Enumerate the addresses on each interface until we find a
     * matching address.
     */
    curr = ifList;
    while (curr != NULL) {
        int count;
        netaddr *addrList;
        netaddr *addrP;

        /* enumerate the addresses on this interface */
        count = enumAddresses_win(env, curr, &addrList);
        if (count < 0) {
            free_netif(ifList);
            return NULL;
        }

        /* iterate through each address */
        addrP = addrList;

        while (addrP != NULL) {
            if ((unsigned long)addr == ntohl(addrP->addr.him4.sin_addr.s_addr)) {
                break;
            }
            addrP = addrP->next;
        }

        /*
         * Address matched so create NetworkInterface for this interface
         * and address list.
         */
        if (addrP != NULL) {
            /* createNetworkInterface will free addrList */
            netifObj = createNetworkInterface(env, curr, count, addrList);
            break;
        }

        /* on next interface */
        curr = curr->next;
    }

    /* release the interface list */
    free_netif(ifList);

    return netifObj;
}

/*
 * Class:     java_net_NetworkInterface
 * Method:    getAll
 * Signature: ()[Ljava/net/NetworkInterface;
 */
JNIEXPORT jobjectArray JNICALL Java_java_net_NetworkInterface_getAll
    (JNIEnv *env, jclass cls)
{
    int count;
    netif *ifList, *curr;
    jobjectArray netIFArr;
    jint arr_index;

    // Retained for now to support IPv4 only stack, java.net.preferIPv4Stack
    if (ipv6_available()) {
        return Java_java_net_NetworkInterface_getAll_XP (env, cls);
    }

    /*
     * Get list of interfaces
     */
    count = enumInterfaces(env, &ifList);
    if (count < 0) {
        return NULL;
    }

    /* allocate a NetworkInterface array */
    netIFArr = (*env)->NewObjectArray(env, count, cls, NULL);
    if (netIFArr == NULL) {
        return NULL;
    }

    /*
     * Iterate through the interfaces, create a NetworkInterface instance
     * for each array element and populate the object.
     */
    curr = ifList;
    arr_index = 0;
    while (curr != NULL) {
        jobject netifObj;

        netifObj = createNetworkInterface(env, curr, -1, NULL);
        if (netifObj == NULL) {
            return NULL;
        }

        /* put the NetworkInterface into the array */
        (*env)->SetObjectArrayElement(env, netIFArr, arr_index++, netifObj);

        curr = curr->next;
    }

    /* release the interface list */
    free_netif(ifList);

    return netIFArr;
}

/*
 * Class:     java_net_NetworkInterface
 * Method:    isUp0
 * Signature: (Ljava/lang/String;)Z
 */
JNIEXPORT jboolean JNICALL Java_java_net_NetworkInterface_isUp0
    (JNIEnv *env, jclass cls, jstring name, jint index) {
  jboolean ret = JNI_FALSE;

  // Retained for now to support IPv4 only stack, java.net.preferIPv4Stack
  if (ipv6_available()) {
    return Java_java_net_NetworkInterface_isUp0_XP(env, cls, name, index);
  } else {
    MIB_IFROW *ifRowP;
    ifRowP = getIF(index);
    if (ifRowP != NULL) {
      ret = ifRowP->dwAdminStatus == MIB_IF_ADMIN_STATUS_UP &&
            (ifRowP->dwOperStatus == MIB_IF_OPER_STATUS_OPERATIONAL ||
             ifRowP->dwOperStatus == MIB_IF_OPER_STATUS_CONNECTED);
      free(ifRowP);
    }
  }
    return ret;
}

/*
 * Class:     java_net_NetworkInterface
 * Method:    isP2P0
 * Signature: (Ljava/lang/String;I)Z
 */
JNIEXPORT jboolean JNICALL Java_java_net_NetworkInterface_isP2P0
    (JNIEnv *env, jclass cls, jstring name, jint index) {
  MIB_IFROW *ifRowP;
  jboolean ret = JNI_FALSE;

  // Retained for now to support IPv4 only stack, java.net.preferIPv4Stack
  if (ipv6_available()) {
    return Java_java_net_NetworkInterface_isP2P0_XP(env, cls, name, index);
  } else {
    ifRowP = getIF(index);
    if (ifRowP != NULL) {
      switch(ifRowP->dwType) {
      case MIB_IF_TYPE_PPP:
      case MIB_IF_TYPE_SLIP:
        ret = JNI_TRUE;
        break;
      }
      free(ifRowP);
    }
  }
  return ret;
}

/*
 * Class:     java_net_NetworkInterface
 * Method:    isLoopback0
 * Signature: (Ljava/lang/String;I)Z
 */
JNIEXPORT jboolean JNICALL Java_java_net_NetworkInterface_isLoopback0
    (JNIEnv *env, jclass cls, jstring name, jint index) {
  MIB_IFROW *ifRowP;
  jboolean ret = JNI_FALSE;

  // Retained for now to support IPv4 only stack, java.net.preferIPv4Stack
  if (ipv6_available()) {
    return Java_java_net_NetworkInterface_isLoopback0_XP(env, cls, name, index);
  } else {
    ifRowP = getIF(index);
    if (ifRowP != NULL) {
      if (ifRowP->dwType == MIB_IF_TYPE_LOOPBACK)
        ret = JNI_TRUE;
      free(ifRowP);
    }
    return ret;
  }
}

/*
 * Class:     java_net_NetworkInterface
 * Method:    supportsMulticast0
 * Signature: (Ljava/lang/String;I)Z
 */
JNIEXPORT jboolean JNICALL Java_java_net_NetworkInterface_supportsMulticast0
    (JNIEnv *env, jclass cls, jstring name, jint index) {
    return Java_java_net_NetworkInterface_supportsMulticast0_XP(env, cls,
                                                               name, index);
}

/*
 * Class:     java_net_NetworkInterface
 * Method:    getMacAddr0
 * Signature: ([bLjava/lang/String;I)[b
 */
JNIEXPORT jbyteArray JNICALL Java_java_net_NetworkInterface_getMacAddr0
    (JNIEnv *env, jclass class, jbyteArray addrArray, jstring name, jint index) {
  jbyteArray ret = NULL;
  int len;
  MIB_IFROW *ifRowP;

  // Retained for now to support IPv4 only stack, java.net.preferIPv4Stack
  if (ipv6_available()) {
    return Java_java_net_NetworkInterface_getMacAddr0_XP(env, class, name, index);
  } else {
    ifRowP = getIF(index);
    if (ifRowP != NULL) {
      switch(ifRowP->dwType) {
      case MIB_IF_TYPE_ETHERNET:
      case MIB_IF_TYPE_TOKENRING:
      case MIB_IF_TYPE_FDDI:
      case IF_TYPE_IEEE80211:
        len = ifRowP->dwPhysAddrLen;
        ret = (*env)->NewByteArray(env, len);
        if (!IS_NULL(ret)) {
          (*env)->SetByteArrayRegion(env, ret, 0, len, (jbyte *) ifRowP->bPhysAddr);
        }
        break;
      }
      free(ifRowP);
    }
    return ret;
  }
}

/*
 * Class:       java_net_NetworkInterface
 * Method:      getMTU0
 * Signature:   ([bLjava/lang/String;I)I
 */
JNIEXPORT jint JNICALL Java_java_net_NetworkInterface_getMTU0
    (JNIEnv *env, jclass class, jstring name, jint index) {
  jint ret = -1;
  MIB_IFROW *ifRowP;

  // Retained for now to support IPv4 only stack, java.net.preferIPv4Stack
  if (ipv6_available()) {
    return Java_java_net_NetworkInterface_getMTU0_XP(env, class, name, index);
  } else {
    ifRowP = getIF(index);
    if (ifRowP != NULL) {
      ret = ifRowP->dwMtu;
      free(ifRowP);
    }
    return ret;
  }
}

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