netdev - Re: linux kernel's IPV6_MULTICAST_HOPS default is 64; should be 1?

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Message-Id: <20100503.234254.150142339.davem@davemloft.net>
Date:	Mon, 03 May 2010 23:42:54 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	enh@...gle.com
Cc:	brian.haley@...com, netdev@...r.kernel.org
Subject: Re: linux kernel's IPV6_MULTICAST_HOPS default is 64; should be 1?

From: enh <enh@...gle.com>
Date: Mon, 3 May 2010 23:27:23 -0700

> On Mon, May 3, 2010 at 23:22, David Miller <davem@...emloft.net> wrote:
>> Ok, I see, so yeah this needs to be fixed to use "1" instead of
>> "-1" in the np->xxx ipv6 socket initialization.
> 
> i think so. there's already the IPV6_DEFAULT_MCASTHOPS constant
> defined to 1 but unused according to gitweb, so you might want to
> either use it or remove it.

I've applied the following, thanks Elliot.

--------------------
ipv6: Fix default multicast hops setting.

As per RFC 3493 the default multicast hops setting
for a socket should be "1" just like ipv4.

Ironically we have a IPV6_DEFAULT_MCASTHOPS macro
it just wasn't being used.

Reported-by: Elliot Hughes <enh@...gle.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
---
 net/ipv6/af_inet6.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 3192aa0..3f9e86b 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -200,7 +200,7 @@ lookup_protocol:
 
 	inet_sk(sk)->pinet6 = np = inet6_sk_generic(sk);
 	np->hop_limit	= -1;
-	np->mcast_hops	= -1;
+	np->mcast_hops	= IPV6_DEFAULT_MCASTHOPS;
 	np->mc_loop	= 1;
 	np->pmtudisc	= IPV6_PMTUDISC_WANT;
 	np->ipv6only	= net->ipv6.sysctl.bindv6only;
-- 
1.7.0.4

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