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Commit cd9ff4de authored by Jim Westfall's avatar Jim Westfall Committed by David S. Miller
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ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY 



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 a263b309
(ipv4: Make neigh lookups directly in output packet path) and later removed
in 0bb4087c (ipv4: Fix neigh lookup keying over loopback/point-to-point
devices) because it was broken.

Signed-off-by: default avatarJim Westfall <jwestfall@surrealistic.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 096b9854

include/net/arp.h

+3 −0
Original line number Diff line number Diff line
@@ -20,6 +20,9 @@ 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);

}

net/ipv4/arp.c

+6 −1
Original line number Diff line number Diff line
@@ -223,11 +223,16 @@ 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) {