ipv4: Fix ARP behavior with many mac-vlans
Ben Greear wrote:
> I have 500 mac-vlans on a system talking to 500 other
> mac-vlans. My problem is that the arp-table gets extremely
> huge because every time an arp-request comes in on all mac-vlans,
> a stale arp entry is added for each mac-vlan. I have filtering
> turned on, but that doesn't help because the neigh_event_ns call
> below will cause a stale neighbor entry to be created regardless
> of whether a replay will be sent or not.
> Maybe the neigh_event code should be below the checks for dont_send,
> and only create check neigh_event_ns if we are !dont_send?
The attached patch makes it work much better for me. The patch
will cause the code to NOT create a stale neighbor entry if we
are not going to respond to the ARP request. The old code
*would* create a stale entry even if we are not going to respond.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 957c87d..29a74c0 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -818,18 +818,18 @@
addr_type = rt->rt_type;
if (addr_type == RTN_LOCAL) {
- n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
- if (n) {
- int dont_send = 0;
+ int dont_send = 0;
- if (!dont_send)
- dont_send |= arp_ignore(in_dev, sip, tip);
- if (!dont_send && IN_DEV_ARPFILTER(in_dev))
- dont_send |= arp_filter(sip, tip, dev);
- if (!dont_send)
+ if (!dont_send)
+ dont_send |= arp_ignore(in_dev,sip,tip);
+ if (!dont_send && IN_DEV_ARPFILTER(in_dev))
+ dont_send |= arp_filter(sip,tip,dev);
+ if (!dont_send) {
+ n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
+ if (n) {
arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha);
-
- neigh_release(n);
+ neigh_release(n);
+ }
}
goto out;
} else if (IN_DEV_FORWARD(in_dev)) {