[RFC] Disable addrconf on ~multicast interfaces?

[RFC] Disable addrconf on ~multicast interfaces?

[Herbert Xu]

Hi Yoshifuji-san:

Are there any non-multicast interfaces that require addrconf?
In other words, what does the following patch break :)

Thanks,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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--
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2130,6 +2130,9 @@ static void addrconf_dev_config(struct n
 		return;
 	}
 
+	if (!(dev->flags & IFF_MULTICAST))
+		return;
+
 	idev = addrconf_add_dev(dev);
 	if (idev == NULL)
 		return;

Re: [RFC] Disable addrconf on ~multicast interfaces?

[YOSHIFUJI Hideaki / 吉藤英明]

In article <20061005053531.GA19482@gondor.apana.org.au> (at Thu, 5 Oct 2006 15:35:31 +1000), Herbert Xu <herbert@gondor.apana.org.au> says:

> Are there any non-multicast interfaces that require addrconf?
> In other words, what does the following patch break :)

Why do you want to do this?  Xen issue?

As Alexey mentioned before, addrconf should work even for !MULTICAST &&
BROADCAST.  This is true for POINTOPOINT as well; ISATAP will use this.

-- 
YOSHIFUJI Hideaki @ USAGI Project  <yoshfuji@linux-ipv6.org>
GPG-FP  : 9022 65EB 1ECF 3AD1 0BDF  80D8 4807 F894 E062 0EEA

Re: [RFC] Disable addrconf on ~multicast interfaces?

[Pekka Savola]

On Thu, 5 Oct 2006, Herbert Xu wrote:
> Are there any non-multicast interfaces that require addrconf?
> In other words, what does the following patch break :)

Point-to-point (or NOARP) interfaces such as tunnels.   I'm not sure 
what are the right flags to check..

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

Re: [RFC] Disable addrconf on ~multicast interfaces?

[Herbert Xu]

On Thu, Oct 05, 2006 at 03:06:34PM +0900, YOSHIFUJI Hideaki / ?$B5HF#1QL@ wrote:
> 
> Why do you want to do this?  Xen issue?

Yes it's to disable addrconf on the Xen bridge interface.

> As Alexey mentioned before, addrconf should work even for !MULTICAST &&
> BROADCAST.  This is true for POINTOPOINT as well; ISATAP will use this.

I'm only proposing this as a stop-gap measure until we have a way to
disable addrconf before ifup, or until Xen loses the netloop interface.

So what I'd like to know is what setups this patch would break.  ISATAP
uses SIT right? This patch only affects Ethernet-type interfaces so it
shouldn't affect SIT at all.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [RFC] Disable addrconf on ~multicast interfaces?

[Herbert Xu]

Pekka Savola <pekkas@netcore.fi> wrote:
> On Thu, 5 Oct 2006, Herbert Xu wrote:
>> Are there any non-multicast interfaces that require addrconf?
>> In other words, what does the following patch break :)
> 
> Point-to-point (or NOARP) interfaces such as tunnels.   I'm not sure 
> what are the right flags to check..

Tunnels shouldn't even get into that function so they aren't
affected.  Are there any Ethernet-like interfaces which do not
set IFF_MULTICAST yet still require addrconf?

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: !! SPAM Suspect : SPAM-URL-DBL !! Re: [RFC] Disable addrconf on ~multicast interfaces?

[Jean-Philippe Andriot]

This patch will break multicast forwarding using the pim6 daemon.
This daemon creates an interface called pim6reg which is not MULTICAST
enabled but needs to be configred by addrconf to get ff00::/8 and
fe80::/64 routes. This is required since the route lookup process has
been enforced to strictly match input interfaces for linklocal and
multicast packets.

Regards,
JP


On Thu, Oct 05, 2006 at 04:35:49PM +1000, Herbert Xu wrote:
> Pekka Savola <pekkas@netcore.fi> wrote:
> > On Thu, 5 Oct 2006, Herbert Xu wrote:
> >> Are there any non-multicast interfaces that require addrconf?
> >> In other words, what does the following patch break :)
> > 
> > Point-to-point (or NOARP) interfaces such as tunnels.   I'm not sure 
> > what are the right flags to check..
> 
> Tunnels shouldn't even get into that function so they aren't
> affected.  Are there any Ethernet-like interfaces which do not
> set IFF_MULTICAST yet still require addrconf?
> 
> Cheers,
> -- 
> Visit Openswan at http://www.openswan.org/
> Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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