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[IPV6]: Fix IPV6_UNICAST_HOPS getsockopt().

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> Relevant standard (RFC 3493) notes:
>
>    The IPV6_UNICAST_HOPS option may be used with getsockopt() to
>    determine the hop limit value that the system will use for subsequent
>    unicast packets sent via that socket.
>
> I don't reckon -1 could be the hop limit value.

-1 means un-initialized.

> IMHO, the value from
> case 1 (if socket is connected to some destination), otherwise case 2
> (if bound to a scope interface) or ultimately the default hop limit
> ought to be returned instead, as it will be most often correct, while
> the current behavior is always wrong, unless setsockopt() has been used
> first. I don't if some people may think doing a route lookup in
> getsockopt might be overly expensive, but at least the two other cases
> should be ok, particularly the last one.

The following patch seems to work for me, but this code has behaved this
way for a while, so don't know if it will break any existing apps.

Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Brian Haley 2006-12-12 17:09:49 -08:00 committed by David S. Miller
parent 832e3ca62d
commit befffe9016
1 changed files with 19 additions and 4 deletions
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21
net/ipv6/ipv6_sockglue.c
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@ -978,12 +978,27 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
break;
case IPV6_UNICAST_HOPS:
val = np->hop_limit;
break;
case IPV6_MULTICAST_HOPS:
{
struct dst_entry *dst;
if (optname == IPV6_UNICAST_HOPS)
val = np->hop_limit;
else
val = np->mcast_hops;
dst = sk_dst_get(sk);
if (dst) {
if (val < 0)
val = dst_metric(dst, RTAX_HOPLIMIT);
if (val < 0)
val = ipv6_get_hoplimit(dst->dev);
dst_release(dst);
}
if (val < 0)
val = ipv6_devconf.hop_limit;
break;
}
case IPV6_MULTICAST_LOOP:
val = np->mc_loop;