[bug-classpath] [Bug classpath/22929] New: NetworkInterface.getNetworkInterfaces() should return condensed results

[pinskia at gcc dot gnu dot org]

Let's describe a network interface whose name is n and which has

addresses a1, a2, ..., an as (n (a1 a2 ... an)), or (n a1) if

n has only on address a1 or addresses other than a1 is ignored.



NetworkInterface.getNetworkInterfaces() should return something

like this:



     ((n1 (a11 a12 a13)) (n2 (a21 a22)))    ---[a]



But it may be the case that VMNetworkInterface.getInterfaces()

returns something like this:



     ((n1 a11) (n1 a12) (n1 a13) (n2 a21) (n2 a22))    ---[b]



So NetworkInterface.getNetworkInterfaces() should condense

the data structure [b] into [a]. But now it simply returns [b].



We may ask VMNetworkInterface.getInterfaces() to return already

condensed data like [a], but I cannot expect that all implementations

of VMNetworkInterface can easily do this.



This will be a problem when a network interface has both IPv4 and

IPv6 addresses.



Kaffe's NetworkInterface is modified to do the condensing.



Please refer to the articles of Kaffe's mailing list around

http://www.kaffe.org/pipermail/kaffe/2005-April/102338.html




------- Additional Comments From from-classpath at savannah dot gnu dot org  
2005-06-07 22:13 -------
This is the patch applied in Kaffe:



2005-04-25  Ito Kazumitsu <address@hidden>



        * libraries/javalib/java/net/NetworkInterface.java

        (getByName, getByInetAddress): call getNetworkInterfaces()

        so that condensed result may be returned.





--- java/net/NetworkInterface.java.orig Wed Apr 20 06:42:21 2005

+++ java/net/NetworkInterface.java      Tue Apr 26 00:47:21 2005

@@ -38,7 +38,12 @@

 

 package java.net;

 

+import java.util.Collection;

+import java.util.Collections;

 import java.util.Enumeration;

+import java.util.HashMap;

+import java.util.Iterator;

+import java.util.Map;

 import java.util.Vector;

 

 /**

@@ -143,9 +148,7 @@

   public static NetworkInterface getByName(String name)

     throws SocketException

   {

-    Vector networkInterfaces = VMNetworkInterface.getInterfaces();

-

-    for (Enumeration e = networkInterfaces.elements(); e.hasMoreElements();)

+    for (Enumeration e = getNetworkInterfaces(); e.hasMoreElements();)

       {

        NetworkInterface tmp = (NetworkInterface) e.nextElement();

 

@@ -170,9 +173,7 @@

   public static NetworkInterface getByInetAddress(InetAddress addr)

     throws SocketException

   {

-    Vector networkInterfaces = VMNetworkInterface.getInterfaces();

-

-    for (Enumeration interfaces = networkInterfaces.elements();

+    for (Enumeration interfaces = getNetworkInterfaces();

          interfaces.hasMoreElements();)

       {

        NetworkInterface tmp = (NetworkInterface) interfaces.nextElement();

@@ -188,6 +189,41 @@

     throw new SocketException("no network interface is bound to such an IP 
address");

   }

 

+  static private Collection condense(Collection interfaces) 

+  {

+    final Map condensed = new HashMap();

+

+    final Iterator interfs = interfaces.iterator();

+    while (interfs.hasNext()) {

+

+      final NetworkInterface face = (NetworkInterface) interfs.next();

+      final String name = face.getName();

+      

+      if (condensed.containsKey(name))

+       {

+         final NetworkInterface conface = (NetworkInterface) 
condensed.get(name);

+         if (!conface.inetAddresses.containsAll(face.inetAddresses))

+           {

+             final Iterator faceAddresses = face.inetAddresses.iterator();

+             while (faceAddresses.hasNext())

+               {

+                 final InetAddress faceAddress = (InetAddress) 
faceAddresses.next();

+                 if (!conface.inetAddresses.contains(faceAddress))

+                   {

+                     conface.inetAddresses.add(faceAddress);

+                   }

+               }

+           }

+       }

+      else

+       {

+         condensed.put(name, face);

+       }

+    }

+

+    return condensed.values();

+  }

+

   /**

    * Return an <code>Enumeration</code> of all available network interfaces

    *

@@ -202,7 +238,9 @@

     if (networkInterfaces.isEmpty())

       return null;

 

-    return networkInterfaces.elements();

+    Collection condensed = condense(networkInterfaces);

+

+    return Collections.enumeration(condensed);

   }

 

   /**


------- Additional Comments From pinskia at gcc dot gnu dot org  2005-08-07 
21:01 -------
Confirmed.

-- 
           Summary: NetworkInterface.getNetworkInterfaces() should return
                    condensed results
           Product: classpath
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P3
         Component: classpath
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: from-classpath at savannah dot gnu dot org
                CC: bug-classpath at gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22929