From: Jim Westfall jwestfall@surrealistic.net
This patch has been added to the 4.1 stable tree. If you have any objections, please let us know.
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[ Upstream commit cd9ff4de0107c65d69d02253bb25d6db93c3dbc1 ]
Map all lookup neigh keys to INADDR_ANY for loopback/point-to-point devices to avoid making an entry for every remote ip the device needs to talk to.
This used the be the old behavior but became broken in a263b3093641f (ipv4: Make neigh lookups directly in output packet path) and later removed in 0bb4087cbec0 (ipv4: Fix neigh lookup keying over loopback/point-to-point devices) because it was broken.
Signed-off-by: Jim Westfall jwestfall@surrealistic.net Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- include/net/arp.h | 3 +++ net/ipv4/arp.c | 7 ++++++- 2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/include/net/arp.h b/include/net/arp.h index 5e0f891d476c..1b3f86981757 100644 --- a/include/net/arp.h +++ b/include/net/arp.h @@ -19,6 +19,9 @@ static inline u32 arp_hashfn(const void *pkey, const struct net_device *dev, u32
static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key) { + if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) + key = INADDR_ANY; + return ___neigh_lookup_noref(&arp_tbl, neigh_key_eq32, arp_hashfn, &key, dev); }
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index a7e74fbf2ce6..24b4174a84bf 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -221,11 +221,16 @@ static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
static int arp_constructor(struct neighbour *neigh) { - __be32 addr = *(__be32 *)neigh->primary_key; + __be32 addr; struct net_device *dev = neigh->dev; struct in_device *in_dev; struct neigh_parms *parms; + u32 inaddr_any = INADDR_ANY;
+ if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) + memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len); + + addr = *(__be32 *)neigh->primary_key; rcu_read_lock(); in_dev = __in_dev_get_rcu(dev); if (!in_dev) {