ARP with wrong ip?

ARP with wrong ip?

[Carlos Velasco]

Hi,

I have a problem with ARP in this machine:
Kernel 2.4.20
1 ethernet interface with IP 192.168.10.1 netmask 255.255.255.0
1 loopback interface with IP 194.147.150.10 netmask 255.255.255.255
default route to 192.168.10.190

Packets are being sent to ethernet interface 192.168.10.1 with IP dst 194.147.150.10.
After receiving these packets it tries to find out the mac address of default gateway (192.168.10.190)... but it's doing it from the wrong src IP address!!

22:49:10.875002 0:b:cd:4d:82:72 ff:ff:ff:ff:ff:ff 0806 60: arp who-has 192.168.10.190 tell 194.147.150.10
22:49:11.867673 0:b:cd:4d:82:72 ff:ff:ff:ff:ff:ff 0806 60: arp who-has 192.168.10.190 tell 194.147.150.10

Is this a bug?

Regards,
Carlos Velasco

[PATCH] Re: ARP with wrong ip?

[Carlos Velasco]

I have submitted a patch for this issue, as it's found in 2.6.0-test1 too.

Can someone take a look to this bug and process the patch?

http://bugzilla.kernel.org/show_bug.cgi?id=978


--- linux-2.6.0-test1/net/ipv4/arp.c      Mon Jul 14 05:37:28 2003
+++ linux-2.6.0-test1-patch/net/ipv4/arp.c    Wed Jul 23 15:31:29 2003
@@ -326,10 +326,14 @@
        u32 target = *(u32*)neigh->primary_key;
        int probes = atomic_read(&neigh->probes);
 
+        /* This don't work if the src addr is a loopback or similar.
+          See http://bugzilla.kernel.org/show_bug.cgi?id=978 
+
        if (skb && inet_addr_type(skb->nh.iph->saddr) == RTN_LOCAL)
                saddr = skb->nh.iph->saddr;
-       else
-               saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
+       else */
+
+       saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);
 
        if ((probes -= neigh->parms->ucast_probes) < 0) {
                if (!(neigh->nud_state&NUD_VALID))


*********** REPLY SEPARATOR  ***********

On 18/07/2003 at 23:57 Carlos Velasco wrote:

>Hi,
>
>I have a problem with ARP in this machine:
>Kernel 2.4.20
>1 ethernet interface with IP 192.168.10.1 netmask 255.255.255.0
>1 loopback interface with IP 194.147.150.10 netmask 255.255.255.255
>default route to 192.168.10.190
>
>Packets are being sent to ethernet interface 192.168.10.1 with IP dst
>194.147.150.10.
>After receiving these packets it tries to find out the mac address of
>default gateway (192.168.10.190)... but it's doing it from the wrong src
>IP address!!
>
>22:49:10.875002 0:b:cd:4d:82:72 ff:ff:ff:ff:ff:ff 0806 60: arp who-has
>192.168.10.190 tell 194.147.150.10
>22:49:11.867673 0:b:cd:4d:82:72 ff:ff:ff:ff:ff:ff 0806 60: arp who-has
>192.168.10.190 tell 194.147.150.10
>
>Is this a bug?
>
>Regards,
>Carlos Velasco
>
>
>-
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Re: [PATCH] Re: ARP with wrong ip?

[David S. Miller]

On Wed, 23 Jul 2003 15:41:18 +0200
"Carlos Velasco" <carlosev@newipnet.com> wrote:

> I have submitted a patch for this issue, as it's found in 2.6.0-test1 too.
> 
> Can someone take a look to this bug and process the patch?
> 
> http://bugzilla.kernel.org/show_bug.cgi?id=978

Maybe if you submitted the bug report and/or patch via
to the "networking" mailing list, instead of linux-kernel
and bugzilla where none of the "networking" developers
pay attention, your report would be more likely to be looked
at.

Re: [PATCH] Re: ARP with wrong ip?

[Carlos Velasco]

On 23/07/2003 at 7:00 David S. Miller wrote:

>Maybe if you submitted the bug report and/or patch via
>to the "networking" mailing list, instead of linux-kernel
>and bugzilla where none of the "networking" developers
>pay attention, your report would be more likely to be looked
>at.

David,

I have sent the bug to linux-net:
http://marc.theaimsgroup.com/?l=linux-net&m=105862200011155&w=2

Where it has been ignored too.

Also, I have searched into ipv4/README:
Maintainers and developers for networking code sections

Code Section            Bug Report Contact
-------------------+-------------------------------------------
ipv4                    davem@caip.rutgers.edu,Eric.Schenk@dna.lth.se

where:

<Eric.Schenk@dna.lth.se>: host himmelsborg.cs.lth.se[130.235.16.11] said: 550
    5.1.1 <Eric.Schenk@dna.lth.se>... User unknown (in reply to RCPT TO
    command)


Also, I have searched into arp.c (the file patched) and seen:

* Fixes:
 *              Alan Cox        :       Removed the Ethernet assumptions in
 *                                      Florian's code

So, I also e-mailed Alan... without reply so far.


David, do you think I need to send the bug and patch to anyone else? Just tell me.

Regards,
Carlos Velasco

Re: [PATCH] Re: ARP with wrong ip?

[David S. Miller]

On Wed, 23 Jul 2003 16:36:28 +0200
"Carlos Velasco" <carlosev@newipnet.com> wrote:

> Also, I have searched into ipv4/README:
> Maintainers and developers for networking code sections

This file has been deleted because it is %100 inaccurate.
It is not the place to look for maintainership.

Oddly enough, proper place for "MAINTAINER" information is in file
"linux/MAINTAINERS".

In that file you will find this entry:

NETWORKING [IPv4/IPv6]
P:      David S. Miller
M:      davem@redhat.com
P:      Alexey Kuznetsov
M:      kuznet@ms2.inr.ac.ru
P:      Pekka Savola (ipv6)
M:      pekkas@netcore.fi
P:      James Morris
M:      jmorris@intercode.com.au
P:      Hideaki YOSHIFUJI
M:      yoshfuji@linux-ipv6.org
L:      netdev@oss.sgi.com
S:      Maintained

Which mentions netdev@oss.sgi.com as the mailing list for
discussions like this one.

linux-net@vger.kernel.org is for mainly user-level configuration
discussions.