[PATCH AUTOSEL 4.19 12/32] net: bridge: when suppression is enabled exclude RARP packets

[Sasha Levin]

From: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>

[ Upstream commit 0353b4a96b7a9f60fe20d1b3ebd4931a4085f91c ]

Recently we had an interop issue where RARP packets got suppressed with
bridge neigh suppression enabled, but the check in the code was meant to
suppress GARP. Exclude RARP packets from it which would allow some VMWare
setups to work, to quote the report:
"Those RARP packets usually get generated by vMware to notify physical
switches when vMotion occurs. vMware may use random sip/tip or just use
sip=tip=0. So the RARP packet sometimes get properly flooded by the vtep
and other times get dropped by the logic"

Reported-by: Amer Abdalamer <amer@xxxxxxxxxx>
Signed-off-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/bridge/br_arp_nd_proxy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/bridge/br_arp_nd_proxy.c b/net/bridge/br_arp_nd_proxy.c
index eb44ae05abaa..b52e70362268 100644
--- a/net/bridge/br_arp_nd_proxy.c
+++ b/net/bridge/br_arp_nd_proxy.c
@@ -158,7 +158,9 @@ void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br,
 	if (br->neigh_suppress_enabled) {
 		if (p && (p->flags & BR_NEIGH_SUPPRESS))
 			return;
-		if (ipv4_is_zeronet(sip) || sip == tip) {
+		if (parp->ar_op != htons(ARPOP_RREQUEST) &&
+		    parp->ar_op != htons(ARPOP_RREPLY) &&
+		    (ipv4_is_zeronet(sip) || sip == tip)) {
 			/* prevent flooding to neigh suppress ports */
 			BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
 			return;
-- 
2.30.2