| From foo@baz Sun 09 Jun 2019 09:24:16 AM CEST |
| From: David Ahern <dsahern@gmail.com> |
| Date: Wed, 1 May 2019 18:18:42 -0700 |
| Subject: neighbor: Call __ipv4_neigh_lookup_noref in neigh_xmit |
| |
| From: David Ahern <dsahern@gmail.com> |
| |
| [ Upstream commit 4b2a2bfeb3f056461a90bd621e8bd7d03fa47f60 ] |
| |
| Commit cd9ff4de0107 changed the key for IFF_POINTOPOINT devices to |
| INADDR_ANY but neigh_xmit which is used for MPLS encapsulations was not |
| updated to use the altered key. The result is that every packet Tx does |
| a lookup on the gateway address which does not find an entry, a new one |
| is created only to find the existing one in the table right before the |
| insert since arp_constructor was updated to reset the primary key. This |
| is seen in the allocs and destroys counters: |
| ip -s -4 ntable show | head -10 | grep alloc |
| |
| which increase for each packet showing the unnecessary overhread. |
| |
| Fix by having neigh_xmit use __ipv4_neigh_lookup_noref for NEIGH_ARP_TABLE. |
| |
| Fixes: cd9ff4de0107 ("ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY") |
| Reported-by: Alan Maguire <alan.maguire@oracle.com> |
| Signed-off-by: David Ahern <dsahern@gmail.com> |
| Tested-by: Alan Maguire <alan.maguire@oracle.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/core/neighbour.c | 9 ++++++++- |
| 1 file changed, 8 insertions(+), 1 deletion(-) |
| |
| --- a/net/core/neighbour.c |
| +++ b/net/core/neighbour.c |
| @@ -31,6 +31,7 @@ |
| #include <linux/times.h> |
| #include <net/net_namespace.h> |
| #include <net/neighbour.h> |
| +#include <net/arp.h> |
| #include <net/dst.h> |
| #include <net/sock.h> |
| #include <net/netevent.h> |
| @@ -2984,7 +2985,13 @@ int neigh_xmit(int index, struct net_dev |
| if (!tbl) |
| goto out; |
| rcu_read_lock_bh(); |
| - neigh = __neigh_lookup_noref(tbl, addr, dev); |
| + if (index == NEIGH_ARP_TABLE) { |
| + u32 key = *((u32 *)addr); |
| + |
| + neigh = __ipv4_neigh_lookup_noref(dev, key); |
| + } else { |
| + neigh = __neigh_lookup_noref(tbl, addr, dev); |
| + } |
| if (!neigh) |
| neigh = __neigh_create(tbl, addr, dev, false); |
| err = PTR_ERR(neigh); |
