ipv6: default route for link local address is not added while assigning a address

ipv6: default route for link local address is not added while assigning a address

[sohny thomas]

Default route for link local address is configured automatically if NETWORKING_IPV6=yes is in ifcfg-eth*.
When the route table for the interface is flushed and a new address is added to the same device with out removing linklocal addr, default route for link local address has to added by default.

I have found the issue to be caused by this checkin

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/net/ipv6?id=62b54dd91567686a1cb118f76a72d5f4764a86dd

According to this change :
He removes adding a link local route if any other address is added , applicable across all interfaces though there's mentioned only lo interface
So below patch fixes for other devices

Signed-off-by: SOhny THomas <sohthoma@linux.vnet.ibm.com>

-----

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index f62c72b..a8a4df9 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1763,6 +1763,16 @@ static int addrconf_ifid_infiniband(u8 *eui, struct net_device *dev)
         return 0;
  }
  
+static void addrconf_add_lroute(struct net_device *dev)
+{
+       struct in6_addr addr;
+
+       ipv6_addr_set(&addr,  htonl(0xFE800000), 0, 0, 0);
+       addrconf_prefix_route(&addr, 64, dev, 0, 0);
+}
+
+
+
  static int __ipv6_isatap_ifid(u8 *eui, __be32 addr)
  {
         if (addr == 0)
@@ -2010,8 +2020,10 @@ static struct inet6_dev *addrconf_add_dev(struct net_device *dev)
                 return ERR_PTR(-EACCES);
  
         /* Add default multicast route */
-       if (!(dev->flags & IFF_LOOPBACK))
+       if (!(dev->flags & IFF_LOOPBACK)){
                 addrconf_add_mroute(dev);
+               addrconf_add_lroute(dev);
+       }
  
         return idev;
  }

Re: ipv6: default route for link local address is not added while assigning a address

[Nicolas Dichtel]

CC: netdev

Le 10/01/2014 13:20, sohny thomas a écrit :
> Default route for link local address is configured automatically if
> NETWORKING_IPV6=yes is in ifcfg-eth*.
> When the route table for the interface is flushed and a new address is added to
> the same device with out removing linklocal addr, default route for link local
> address has to added by default.
I would say that removing the link local route but not the link local address
is a configuration problem.
If you remove a connected route but not the associated address, you will have
the same problem.

>
> I have found the issue to be caused by this checkin
>
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/net/ipv6?id=62b54dd91567686a1cb118f76a72d5f4764a86dd
>
>
> According to this change :
> He removes adding a link local route if any other address is added , applicable
> across all interfaces though there's mentioned only lo interface
> So below patch fixes for other devices

Re: ipv6: default route for link local address is not added while assigning a address

[Hannes Frederic Sowa]

On Fri, Jan 10, 2014 at 05:33:08PM +0100, Nicolas Dichtel wrote:
> CC: netdev
> 
> Le 10/01/2014 13:20, sohny thomas a écrit :
> >Default route for link local address is configured automatically if
> >NETWORKING_IPV6=yes is in ifcfg-eth*.
> >When the route table for the interface is flushed and a new address is 
> >added to
> >the same device with out removing linklocal addr, default route for link 
> >local
> >address has to added by default.
> I would say that removing the link local route but not the link local 
> address
> is a configuration problem.
> If you remove a connected route but not the associated address, you will 
> have
> the same problem.

We have some user accessible routes that are essential for IPv6 stack
to work at all. So I don't know if I can agree with that.

Maybe flush is a bit too aggressive?

Re: ipv6: default route for link local address is not added while assigning a address

[sohny thomas]

On Friday 10 January 2014 10:46 PM, Hannes Frederic Sowa wrote:
> On Fri, Jan 10, 2014 at 05:33:08PM +0100, Nicolas Dichtel wrote:
>> CC: netdev
>>
>> Le 10/01/2014 13:20, sohny thomas a écrit :
>>> Default route for link local address is configured automatically if
>>> NETWORKING_IPV6=yes is in ifcfg-eth*.
>>> When the route table for the interface is flushed and a new address is
>>> added to
>>> the same device with out removing linklocal addr, default route for link
>>> local
>>> address has to added by default.
>> I would say that removing the link local route but not the link local
>> address
>> is a configuration problem.
>> If you remove a connected route but not the associated address, you will
>> have
>> the same problem.
> We have some user accessible routes that are essential for IPv6 stack
> to work at all. So I don't know if I can agree with that.
>
> Maybe flush is a bit too aggressive?
>
Hi ,

Thank you for the inputs.

In the test for ipv6 default address selection , we are testing the rule
2 as specified in RFC 6724

   If Scope(SA) < Scope(SB): If Scope(SA) < Scope(D), then prefer SB
     and otherwise prefer SA.
     Similarly, if Scope(SB) < Scope(SA): If Scope(SB) < Scope(D), then
     prefer SA and otherwise prefer SB.

Test:

   Check 04:
      Destination: ff08::2(OS)
      Candidate Source Addresses: fec0::1(SS) or LLA(LS)
      Result: fec0::1(SS)

      Scope(LLA) < Scope(fec0::1): If Scope(LLA) < Scope(ff08::2),  yes, 
prefer fec0::1


Now in the test its flushing all the routes and adding an address ,
which in causes to add route into the routing table including the link
local routes.
Earlier in 2.6.32 it used to work fine now due to the above mentioned
check-in this is not happening

Of course we can still just delete a route and add , but even if we
delete the link local route, IMHO i think it should update the LLA route
when the interface is next added an address or bought up which ever is
the case.

Regards,
Sohny

Re: ipv6: default route for link local address is not added while assigning a address

[sohny thomas]

Hi All,

Any updates on my reply, Any more info is required.
Can this be pulled into the kernel tree?

Thanks & Regards,
Sohny


On Monday 13 January 2014 02:19 PM, sohny thomas wrote:
> On Friday 10 January 2014 10:46 PM, Hannes Frederic Sowa wrote:
>> On Fri, Jan 10, 2014 at 05:33:08PM +0100, Nicolas Dichtel wrote:
>>> CC: netdev
>>>
>>> Le 10/01/2014 13:20, sohny thomas a écrit :
>>>> Default route for link local address is configured automatically if
>>>> NETWORKING_IPV6=yes is in ifcfg-eth*.
>>>> When the route table for the interface is flushed and a new address is
>>>> added to
>>>> the same device with out removing linklocal addr, default route for
>>>> link
>>>> local
>>>> address has to added by default.
>>> I would say that removing the link local route but not the link local
>>> address
>>> is a configuration problem.
>>> If you remove a connected route but not the associated address, you will
>>> have
>>> the same problem.
>> We have some user accessible routes that are essential for IPv6 stack
>> to work at all. So I don't know if I can agree with that.
>>
>> Maybe flush is a bit too aggressive?
>>
> Hi ,
>
> Thank you for the inputs.
>
> In the test for ipv6 default address selection , we are testing the rule
> 2 as specified in RFC 6724
>
>    If Scope(SA) < Scope(SB): If Scope(SA) < Scope(D), then prefer SB
>      and otherwise prefer SA.
>      Similarly, if Scope(SB) < Scope(SA): If Scope(SB) < Scope(D), then
>      prefer SA and otherwise prefer SB.
>
> Test:
>
>    Check 04:
>       Destination: ff08::2(OS)
>       Candidate Source Addresses: fec0::1(SS) or LLA(LS)
>       Result: fec0::1(SS)
>
>       Scope(LLA) < Scope(fec0::1): If Scope(LLA) < Scope(ff08::2),  yes,
> prefer fec0::1
>
>
> Now in the test its flushing all the routes and adding an address ,
> which in causes to add route into the routing table including the link
> local routes.
> Earlier in 2.6.32 it used to work fine now due to the above mentioned
> check-in this is not happening
>
> Of course we can still just delete a route and add , but even if we
> delete the link local route, IMHO i think it should update the LLA route
> when the interface is next added an address or bought up which ever is
> the case.
>
> Regards,
> Sohny
>
>

Re: ipv6: default route for link local address is not added while assigning a address

[Hannes Frederic Sowa]

Hi!

On Fri, Jan 17, 2014 at 02:04:26PM +0530, sohny thomas wrote:
> Any updates on my reply, Any more info is required.
> Can this be pulled into the kernel tree?

Your patch was posted to the wrong mailing list. Please repost to
netdev@vger.kernel.org so <http://patchwork.ozlabs.org/project/netdev/list/>
picks it up.

Thanks,

  Hannes