Subject: [PATCH net-next v5 07/12] net: vxlan: make vxlan_set_mac() return drop reasons

From: Menglong Dong <[email-masked]>
Date: Sun, 6 Oct 2024 14:56:11 +0800

Change the return type of vxlan_set_mac() from bool to enum
skb_drop_reason. In this commit, the drop reason
"SKB_DROP_REASON_LOCAL_MAC" is introduced for the case that the source
mac of the packet is a local mac.

Signed-off-by: Menglong Dong <[email-masked]>
Reviewed-by: Simon Horman <[email-masked]>
---
v5:
- modify the document of SKB_DROP_REASON_LOCAL_MAC
v3:
- adjust the call of vxlan_set_mac()
- add SKB_DROP_REASON_LOCAL_MAC
---
 drivers/net/vxlan/vxlan_core.c | 19 ++++++++++---------
 include/net/dropreason-core.h  |  6 ++++++
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 1a81a3957327..41191a28252a 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -1609,9 +1609,9 @@ static void vxlan_parse_gbp_hdr(struct vxlanhdr *unparsed,
 	unparsed->vx_flags &= ~VXLAN_GBP_USED_BITS;
 }
 
-static bool vxlan_set_mac(struct vxlan_dev *vxlan,
-			  struct vxlan_sock *vs,
-			  struct sk_buff *skb, __be32 vni)
+static enum skb_drop_reason vxlan_set_mac(struct vxlan_dev *vxlan,
+					  struct vxlan_sock *vs,
+					  struct sk_buff *skb, __be32 vni)
 {
 	union vxlan_addr saddr;
 	u32 ifindex = skb->dev->ifindex;
@@ -1622,7 +1622,7 @@ static bool vxlan_set_mac(struct vxlan_dev *vxlan,
 
 	/* Ignore packet loops (and multicast echo) */
 	if (ether_addr_equal(eth_hdr(skb)->h_source, vxlan->dev->dev_addr))
-		return false;
+		return SKB_DROP_REASON_LOCAL_MAC;
 
 	/* Get address from the outer IP header */
 	if (vxlan_get_sk_family(vs) == AF_INET) {
@@ -1635,11 +1635,11 @@ static bool vxlan_set_mac(struct vxlan_dev *vxlan,
 #endif
 	}
 
-	if ((vxlan->cfg.flags & VXLAN_F_LEARN) &&
-	    vxlan_snoop(skb->dev, &saddr, eth_hdr(skb)->h_source, ifindex, vni))
-		return false;
+	if (!(vxlan->cfg.flags & VXLAN_F_LEARN))
+		return SKB_NOT_DROPPED_YET;
 
-	return true;
+	return vxlan_snoop(skb->dev, &saddr, eth_hdr(skb)->h_source,
+			   ifindex, vni);
 }
 
 static bool vxlan_ecn_decapsulate(struct vxlan_sock *vs, void *oiph,
@@ -1774,7 +1774,8 @@ static int vxlan_rcv(struct sock *sk, struct sk_buff *skb)
 	}
 
 	if (!raw_proto) {
-		if (!vxlan_set_mac(vxlan, vs, skb, vni))
+		reason = vxlan_set_mac(vxlan, vs, skb, vni);
+		if (reason)
 			goto drop;
 	} else {
 		skb_reset_mac_header(skb);
diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h
index 1cb8d7c953be..fbf92d442c1b 100644
--- a/include/net/dropreason-core.h
+++ b/include/net/dropreason-core.h
@@ -97,6 +97,7 @@
 	FN(MAC_INVALID_SOURCE)		\
 	FN(VXLAN_ENTRY_EXISTS)		\
 	FN(IP_TUNNEL_ECN)		\
+	FN(LOCAL_MAC)			\
 	FNe(MAX)
 
 /**
@@ -443,6 +444,11 @@ enum skb_drop_reason {
 	 * RFC 6040 4.2, see __INET_ECN_decapsulate() for detail.
 	 */
 	SKB_DROP_REASON_IP_TUNNEL_ECN,
+	/**
+	 * @SKB_DROP_REASON_LOCAL_MAC: the source MAC address is equal to
+	 * the MAC address of the local netdev.
+	 */
+	SKB_DROP_REASON_LOCAL_MAC,
 	/**
 	 * @SKB_DROP_REASON_MAX: the maximum of core drop reasons, which
 	 * shouldn't be used as a real 'reason' - only for tracing code gen
-- 
2.39.5