From: Doug Kehn <rdkehn@yahoo•com>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: netdev@vger•kernel.org, Timo Teras <timo.teras@iki•fi>
Subject: Re: Multicast Fails Over Multipoint GRE Tunnel
Date: Tue, 15 Mar 2011 14:24:42 -0700 (PDT) [thread overview]
Message-ID: <736238.4685.qm@web39308.mail.mud.yahoo.com> (raw)
In-Reply-To: <1300203277.2927.9.camel@edumazet-laptop>
Hi Eric,
--- On Tue, 3/15/11, Eric Dumazet <eric.dumazet@gmail•com> wrote:
> From: Eric Dumazet <eric.dumazet@gmail•com>
> Subject: Re: Multicast Fails Over Multipoint GRE Tunnel
> To: "Doug Kehn" <rdkehn@yahoo•com>
> Cc: netdev@vger•kernel.org, "Timo Teras" <timo.teras@iki•fi>
> Date: Tuesday, March 15, 2011, 11:34 AM
> Le lundi 14 mars 2011 à 16:34 -0700,
> Doug Kehn a écrit :
> > Hi All,
> >
> > I'm running kernel version 2.6.36 on ARM XSCALE
> (big-endian) and multicast over a multipoint GRE tunnel
> isn't working. For my architecture, this worked on
> 2.6.26.8. For x86, multicast over a multipoint GRE
> tunnel worked with kernel version 2.6.31 but failed with
> version 2.6.35. Multicast over a multipoint GRE tunnel
> fails because ipgre_header() fails the 'if (iph->daddr)'
> check and reutrns -t->hlen. ipgre_header() is being
> called, from neigh_connected_output(), with a non-null
> daddr; the contents of daddr is zero.
> >
> > Reverting the ip_gre.c patch posted in http://marc.info/?l=linux-netdev&m=126762491525281&w=2
> resolves the problem. (Reviewing the HEAD of
> net-next-2.6 it appears that ipgre_header() remains
> unchanged from 2.6.36.)
> >
> > The configuration used to discover/diagnose the
> problem:
> >
> > ip tunnel add tun1 mode gre key 11223344 ttl 64 csum
> remote any
> > ip link set dev tun1 up
> > ip link set dev tun1 multicast on
> > ip addr flush dev tun1
> > ip addr add 10.40.92.114/24 broadcast 10.40.92.255 dev
> tun1
> >
> > 12: tun1: <MULTICAST,NOARP,UP,10000> mtu 1468
> qdisc noqueue
> > link/gre 0.0.0.0 brd 0.0.0.0
> > inet 10.40.92.114/24 brd
> 10.40.92.255 scope global tun1
> >
> > Then attempt:
> > ping -I tun1 224.0.0.9
> >
> > Are additional configuration steps now required for
> multicast over multipoint GRE tunnel or is ipgre_header() in
> error?
>
> Hi Doug
>
> CC Timo Teras <timo.teras@iki•fi>
>
> I would do a partial revert of Timo patch, but this means
> initial
> concern should be addressed ?
>
> (Timo mentioned :
> If the NOARP packets are not dropped,
> ipgre_tunnel_xmit() will
> take rt->rt_gateway (= NBMA IP) and
> use that for route
> look up (and may lead to bogus xfrm
> acquires).)
>
>
> Is the following works for you ?
>
> diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
> index da5941f..47844fa2 100644
> --- a/net/ipv4/ip_gre.c
> +++ b/net/ipv4/ip_gre.c
> @@ -1170,8 +1170,10 @@ static int ipgre_header(struct
> sk_buff *skb, struct net_device *dev,
>
> if (saddr)
>
> memcpy(&iph->saddr, saddr, 4);
> - if (daddr)
> + if (daddr) {
>
> memcpy(&iph->daddr, daddr, 4);
> + return t->hlen;
> + }
> if (iph->daddr)
> return t->hlen;
>
Yes, the partial revert does work.
Regards,
...doug
prev parent reply other threads:[~2011-03-15 21:24 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-14 23:34 Multicast Fails Over Multipoint GRE Tunnel Doug Kehn
2011-03-15 15:34 ` Eric Dumazet
2011-03-15 16:36 ` Timo Teräs
2011-03-15 18:28 ` Timo Teräs
2011-03-15 21:33 ` Doug Kehn
2011-03-15 21:35 ` Doug Kehn
2011-03-16 6:01 ` Timo Teräs
2011-03-16 20:02 ` Doug Kehn
2011-03-27 16:17 ` Timo Teräs
2011-03-29 8:40 ` [PATCH] net: gre: provide multicast mappings for ipv4 and ipv6 Timo Teräs
2011-03-29 9:11 ` Eric Dumazet
2011-03-29 10:00 ` Timo Teräs
2011-03-29 20:26 ` Doug Kehn
2011-03-30 7:11 ` David Miller
2011-03-15 21:24 ` Doug Kehn [this message]
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