Messages in this thread | | | Date | Wed, 9 Jul 2014 04:47:59 +0400 | From | Dmitry Popov <> | Subject | Re: [PATCH] ip_tunnel: fix ip_tunnel_lookup |
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On Tue, 08 Jul 2014 15:12:10 -0700 (PDT) David Miller <davem@davemloft.net> wrote:
> From: Dmitry Popov <ixaphire@qrator.net> > Date: Sat, 5 Jul 2014 02:26:37 +0400 > > > @@ -205,6 +207,8 @@ struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn, > > > > hlist_for_each_entry_rcu(t, head, hash_node) { > > if (t->parms.i_key != key || > > + t->parms.iph.saddr != 0 || > > + t->parms.iph.daddr != 0 || > > !(t->dev->flags & IFF_UP)) > > continue; > > > > I don't really understand the logic of these tests. > > Usually the canonical way to test these kinds of things is: > > if (parms->saddr && parms->saddr != saddr) > goto no_match; > > But you are signalling a non-match any time the address is not a > wildcard. > > Why?
Because that's exactly what I want: to skip any non-wildcard tunnels.
How I see ip_tunnel_lookup logic: 1) try to find exact match (and if found return this tunnel): tunnel.saddr == iph.daddr && tunnel.daddr == iph.saddr && key_matched() 2) try to find matched (local) wildcard tunnel: tunnel.saddr == any && tunnel.daddr == iph.saddr && key_matched() 3) try to find matched (remote) wildcard tunnel: tunnel.saddr == iph.daddr && tunnel.daddr == any && key_matched() (there is also a test for multicast tunnel, but let's skip it for simplicity) 4) try to find matched (full) wildcard tunnel: tunnel.saddr == any && tunnel.daddr == any && key_matched() 5) if nothing found return default tunnel.
According to this logic, in 4th loop (the one you quoted) we have to test that tunnel.daddr == any && tunnel.saddr == any. In my opinion those two new lines are the best way to achieve it.
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