From: David Ahern dsahern@gmail.com
commit 0b5e2e39739e861fa5fc84ab27a35dbe62a15330 upstream.
I got too fancy consolidating checks on multipath type. The result is that path lookups can access 2 different nh_grp structs as exposed by Nik's torture tests. Expand nexthop_is_multipath within nexthop.h to avoid multiple, nh_grp dereferences and make decisions based on the consistent struct.
Only 2 places left using nexthop_is_multipath are within IPv6, both only check that the nexthop is a multipath for a branching decision which are acceptable.
Fixes: 430a049190de ("nexthop: Add support for nexthop groups") Signed-off-by: David Ahern dsahern@gmail.com Acked-by: Nikolay Aleksandrov nikolay@cumulusnetworks.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- include/net/nexthop.h | 41 +++++++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 16 deletions(-)
--- a/include/net/nexthop.h +++ b/include/net/nexthop.h @@ -137,21 +137,20 @@ static inline unsigned int nexthop_num_p { unsigned int rc = 1;
- if (nexthop_is_multipath(nh)) { + if (nh->is_group) { struct nh_group *nh_grp;
nh_grp = rcu_dereference_rtnl(nh->nh_grp); - rc = nh_grp->num_nh; + if (nh_grp->mpath) + rc = nh_grp->num_nh; }
return rc; }
static inline -struct nexthop *nexthop_mpath_select(const struct nexthop *nh, int nhsel) +struct nexthop *nexthop_mpath_select(const struct nh_group *nhg, int nhsel) { - const struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp); - /* for_nexthops macros in fib_semantics.c grabs a pointer to * the nexthop before checking nhsel */ @@ -186,12 +185,14 @@ static inline bool nexthop_is_blackhole( { const struct nh_info *nhi;
- if (nexthop_is_multipath(nh)) { - if (nexthop_num_path(nh) > 1) - return false; - nh = nexthop_mpath_select(nh, 0); - if (!nh) + if (nh->is_group) { + struct nh_group *nh_grp; + + nh_grp = rcu_dereference_rtnl(nh->nh_grp); + if (nh_grp->num_nh > 1) return false; + + nh = nh_grp->nh_entries[0].nh; }
nhi = rcu_dereference_rtnl(nh->nh_info); @@ -217,10 +218,15 @@ struct fib_nh_common *nexthop_fib_nhc(st BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0); BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
- if (nexthop_is_multipath(nh)) { - nh = nexthop_mpath_select(nh, nhsel); - if (!nh) - return NULL; + if (nh->is_group) { + struct nh_group *nh_grp; + + nh_grp = rcu_dereference_rtnl(nh->nh_grp); + if (nh_grp->mpath) { + nh = nexthop_mpath_select(nh_grp, nhsel); + if (!nh) + return NULL; + } }
nhi = rcu_dereference_rtnl(nh->nh_info); @@ -264,8 +270,11 @@ static inline struct fib6_nh *nexthop_fi { struct nh_info *nhi;
- if (nexthop_is_multipath(nh)) { - nh = nexthop_mpath_select(nh, 0); + if (nh->is_group) { + struct nh_group *nh_grp; + + nh_grp = rcu_dereference_rtnl(nh->nh_grp); + nh = nexthop_mpath_select(nh_grp, 0); if (!nh) return NULL; }