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ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY

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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 a263b30936
(ipv4: Make neigh lookups directly in output packet path) and later removed
in 0bb4087cbe (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>
This commit is contained in:
Jim Westfall 2018-01-14 04:18:51 -08:00 committed by David S. Miller
parent 096b9854c0
commit cd9ff4de01
2 changed files with 9 additions and 1 deletions
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3
include/net/arp.h
View File

@ -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);
}

7
net/ipv4/arp.c
View File

@ -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) {