2013-10-10 17:51:01

by Oussama Ghorbel

Subject: [PATCH] ipv6: Initialize ip6_tnl.hlen in gre tunnel even if no route is found

The ip6_tnl.hlen (gre and ipv6 headers length) is independent from the
outgoing interface, so it would be better to initialize it even when no
route is found, otherwise its value will be zero.
While I'm not sure if this could happen in real life, but doing that
will avoid to call the skb_push function with a zero in ip6gre_header
function.

Suggested-by: Hannes Frederic Sowa <[email protected]>
Signed-off-by: Oussama Ghorbel <[email protected]>
---
net/ipv6/ip6_gre.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 90747f1..8e4d42e 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -978,6 +978,7 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
if (t->parms.o_flags&GRE_SEQ)
addend += 4;
}
+ t->hlen = addend;

if (p->flags & IP6_TNL_F_CAP_XMIT) {
int strict = (ipv6_addr_type(&p->raddr) &
@@ -1004,8 +1005,6 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
}
ip6_rt_put(rt);
}
-
- t->hlen = addend;
}

static int ip6gre_tnl_change(struct ip6_tnl *t,
--
1.7.9.5

2013-10-11 15:02:20

by Hannes Frederic Sowa

Subject: Re: [PATCH] ipv6: Initialize ip6_tnl.hlen in gre tunnel even if no route is found

On Thu, Oct 10, 2013 at 06:50:27PM +0100, Oussama Ghorbel wrote:
> The ip6_tnl.hlen (gre and ipv6 headers length) is independent from the
> outgoing interface, so it would be better to initialize it even when no
> route is found, otherwise its value will be zero.
> While I'm not sure if this could happen in real life, but doing that
> will avoid to call the skb_push function with a zero in ip6gre_header
> function.
>
> Suggested-by: Hannes Frederic Sowa <[email protected]>
> Signed-off-by: Oussama Ghorbel <[email protected]>

Acked-by: Hannes Frederic Sowa <[email protected]>

Thanks,

Hannes

2013-10-11 21:55:39

by David Miller

Subject: Re: [PATCH] ipv6: Initialize ip6_tnl.hlen in gre tunnel even if no route is found

From: Hannes Frederic Sowa <[email protected]>
Date: Fri, 11 Oct 2013 17:02:17 +0200

> On Thu, Oct 10, 2013 at 06:50:27PM +0100, Oussama Ghorbel wrote:
>> The ip6_tnl.hlen (gre and ipv6 headers length) is independent from the
>> outgoing interface, so it would be better to initialize it even when no
>> route is found, otherwise its value will be zero.
>> While I'm not sure if this could happen in real life, but doing that
>> will avoid to call the skb_push function with a zero in ip6gre_header
>> function.
>>
>> Suggested-by: Hannes Frederic Sowa <[email protected]>
>> Signed-off-by: Oussama Ghorbel <[email protected]>
>
> Acked-by: Hannes Frederic Sowa <[email protected]>

Applied.