[PATCH v2 net-next] net: dropreason: add MACVLAN_BROADCAST_BACKLOG and IPVLAN_MULTICAST_BACKLOG

[PATCH v2 net-next] net: dropreason: add MACVLAN_BROADCAST_BACKLOG and IPVLAN_MULTICAST_BACKLOG

[Eric Dumazet]

ipvlan and macvlan use queues to process broadcast/multicast packets
from a work queue.

Under attack these queues can drop packets.

Add MACVLAN_BROADCAST_BACKLOG drop_reason for macvlan broadcast queue.

Add IPVLAN_MULTICAST_BACKLOG drop_reason for ipvlan multicast queue.

Use different reasons as some deployments use both ipvlan and macvlan.

Also change ipvlan_rcv_frame() to use SKB_DROP_REASON_DEV_READY
when the device is not UP.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 drivers/net/ipvlan/ipvlan_core.c |  4 ++--
 drivers/net/macvlan.c            |  2 +-
 include/net/dropreason-core.h    | 12 ++++++++++++
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index 68fdb42068d0060c67d751b869a059e8cb1b6bd1..5131d722c476eaa6149c114bcfc7267ea31d7242 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -337,7 +337,7 @@ static int ipvlan_rcv_frame(struct ipvl_addr *addr, struct sk_buff **pskb,
 	 */
 	if (local) {
 		if (unlikely(!(dev->flags & IFF_UP))) {
-			kfree_skb(skb);
+			kfree_skb_reason(skb, SKB_DROP_REASON_DEV_READY);
 			goto out;
 		}
 
@@ -596,7 +596,7 @@ static void ipvlan_multicast_enqueue(struct ipvl_port *port,
 	} else {
 		spin_unlock(&port->backlog.lock);
 		dev_core_stats_rx_dropped_inc(skb->dev);
-		kfree_skb(skb);
+		kfree_skb_reason(skb, SKB_DROP_REASON_IPVLAN_MULTICAST_BACKLOG);
 	}
 }
 
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 54c514acacc5e24fcdb88904f41fd1d29b1e34d0..9f90c598649d548ee12b0a9806c825f96a4a4d63 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -386,7 +386,7 @@ static void macvlan_broadcast_enqueue(struct macvlan_port *port,
 	return;
 
 free_nskb:
-	kfree_skb(nskb);
+	kfree_skb_reason(nskb, SKB_DROP_REASON_MACVLAN_BROADCAST_BACKLOG);
 err:
 	dev_core_stats_rx_dropped_inc(skb->dev);
 }
diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h
index de61dd5dbfd9dc7d91d22d79a510d42fb69eb60a..5ad4a34b527486d3302238634f5a1a0af26db3db 100644
--- a/include/net/dropreason-core.h
+++ b/include/net/dropreason-core.h
@@ -69,6 +69,8 @@
 	FN(QDISC_DROP)			\
 	FN(QDISC_BURST_DROP)		\
 	FN(CPU_BACKLOG)			\
+	FN(MACVLAN_BROADCAST_BACKLOG)		\
+	FN(IPVLAN_MULTICAST_BACKLOG)		\
 	FN(XDP)				\
 	FN(TC_INGRESS)			\
 	FN(UNHANDLED_PROTO)		\
@@ -382,6 +384,16 @@ enum skb_drop_reason {
 	 * netdev_max_backlog in net.rst) or RPS flow limit
 	 */
 	SKB_DROP_REASON_CPU_BACKLOG,
+	/**
+	 * @SKB_DROP_REASON_MACVLAN_BROADCAST_BACKLOG: failed to enqueue the skb
+	 * to macvlan broadcast queue.
+	 */
+	SKB_DROP_REASON_MACVLAN_BROADCAST_BACKLOG,
+	/**
+	 * @SKB_DROP_REASON_IPVLAN_MULTICAST_BACKLOG: failed to enqueue the skb
+	 * to ipvlan multicast queue.
+	 */
+	SKB_DROP_REASON_IPVLAN_MULTICAST_BACKLOG,
 	/** @SKB_DROP_REASON_XDP: dropped by XDP in input path */
 	SKB_DROP_REASON_XDP,
 	/** @SKB_DROP_REASON_TC_INGRESS: dropped in TC ingress HOOK */
-- 
2.53.0.1213.gd9a14994de-goog