From: Eyal Birger <eyal.birger@xxxxxxxxx>
[ Upstream commit 9f8550e4bd9d78a8436c2061ad2530215f875376 ]
The disable_xfrm flag signals that xfrm should not be performed during
routing towards a device before reaching device xmit.
For xfrm interfaces this is usually desired as they perform the outbound
policy lookup as part of their xmit using their if_id.
Before this change enabling this flag on xfrm interfaces prevented them
from xmitting as xfrm_lookup_with_ifid() would not perform a policy lookup
in case the original dst had the DST_NOXFRM flag.
This optimization is incorrect when the lookup is done by the xfrm
interface xmit logic.
Fix by performing policy lookup when invoked by xfrmi as if_id != 0.
Similarly it's unlikely for the 'no policy exists on net' check to yield
any performance benefits when invoked from xfrmi.
Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces")
Signed-off-by: Eyal Birger <eyal.birger@xxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/xfrm/xfrm_policy.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 939f3adf075aa..e9aea82f370de 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2101,8 +2101,8 @@ struct dst_entry *xfrm_lookup_with_ifid(struct net *net,
xflo.flags = flags;
/* To accelerate a bit... */
- if ((dst_orig->flags & DST_NOXFRM) ||
- !net->xfrm.policy_count[XFRM_POLICY_OUT])
+ if (!if_id && ((dst_orig->flags & DST_NOXFRM) ||
+ !net->xfrm.policy_count[XFRM_POLICY_OUT]))
goto nopol;
xdst = xfrm_bundle_lookup(net, fl, family, dir, &xflo, if_id);
--
2.27.0
