Subject: Re: [PATCH net 1/2] ipv6: enforce flowi6_oif usage in ip6_dst_lookup_tail()

From: Paolo Abeni <[email-masked]>
Date: Thu, 28 Jan 2016 13:27:30 +0100

On Wed, 2016-01-27 at 19:38 +0100, Hannes Frederic Sowa wrote:
> On 27.01.2016 14:45, Paolo Abeni wrote:
> > diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> > index 3c8834b..973cb73 100644
> > --- a/net/ipv6/route.c
> > +++ b/net/ipv6/route.c
> > @@ -1183,11 +1183,10 @@ static struct rt6_info *ip6_pol_route_output(struct net *net, struct fib6_table
> >   	return ip6_pol_route(net, table, fl6->flowi6_oif, fl6, flags);
> >   }
> >
> > -struct dst_entry *ip6_route_output(struct net *net, const struct sock *sk,
> > -				    struct flowi6 *fl6)
> > +struct dst_entry *ip6_route_output_flags(struct net *net, const struct sock *sk,
> > +					 struct flowi6 *fl6, int flags)
> >   {
> >   	struct dst_entry *dst;
> > -	int flags = 0;
> >   	bool any_src;
> >
> >   	dst = l3mdev_rt6_dst_by_oif(net, fl6);
> > @@ -1208,6 +1207,13 @@ struct dst_entry *ip6_route_output(struct net *net, const struct sock *sk,
> >
> >   	return fib6_rule_lookup(net, fl6, flags, ip6_pol_route_output);
> >   }
> > +EXPORT_SYMBOL_GPL(ip6_route_output_flags);
> > +
> > +struct dst_entry *ip6_route_output(struct net *net, const struct sock *sk,
> > +				   struct flowi6 *fl6)
> > +{
> > +	return ip6_route_output_flags(net, sk, fl6, 0);
> > +}
> >   EXPORT_SYMBOL(ip6_route_output);
> 
> I think this can just be a static inline function.
> 
> Is it a lot of work to introduce the flags argument globally? Most other 
> functions already have a flags parameter, maybe instead of just adding 
> another wrapper just bite the bullet and add it everywhere?

There are ~20 call sites for ip6_route_output(). Replacing them with
ip6_route_output_flags() should be trivial, but it sounds quite
invasive. Moving the new ip6_route_output() definition into the header
file as static inline function should be pretty much equivalent, may I
go with the latter option ?

Cheers,

Paolo