Subject: [PATCH net-next 1/3] net: bridge: add fdb flag to extent locked port feature

From: Hans Schultz <[email-masked]>
Date: Thu, 10 Mar 2022 15:23:18 +0100

Add an intermediate state for clients behind a locked port to allow for
possible opening of the port for said clients. This feature corresponds
to the Mac-Auth and MAC Authentication Bypass (MAB) named features. The
latter defined by Cisco.

Signed-off-by: Hans Schultz <[email-masked]>
---
 include/uapi/linux/neighbour.h |  1 +
 net/bridge/br_fdb.c            |  6 ++++++
 net/bridge/br_input.c          | 11 ++++++++++-
 net/bridge/br_private.h        |  3 ++-
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/neighbour.h b/include/uapi/linux/neighbour.h
index db05fb55055e..83115a592d58 100644
--- a/include/uapi/linux/neighbour.h
+++ b/include/uapi/linux/neighbour.h
@@ -208,6 +208,7 @@ enum {
 	NFEA_UNSPEC,
 	NFEA_ACTIVITY_NOTIFY,
 	NFEA_DONT_REFRESH,
+	NFEA_LOCKED,
 	__NFEA_MAX
 };
 #define NFEA_MAX (__NFEA_MAX - 1)
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 6ccda68bd473..396dcf3084cf 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -105,6 +105,7 @@ static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
 	struct nda_cacheinfo ci;
 	struct nlmsghdr *nlh;
 	struct ndmsg *ndm;
+	u8 ext_flags = 0;
 
 	nlh = nlmsg_put(skb, portid, seq, type, sizeof(*ndm), flags);
 	if (nlh == NULL)
@@ -125,11 +126,16 @@ static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
 		ndm->ndm_flags |= NTF_EXT_LEARNED;
 	if (test_bit(BR_FDB_STICKY, &fdb->flags))
 		ndm->ndm_flags |= NTF_STICKY;
+	if (test_bit(BR_FDB_ENTRY_LOCKED, &fdb->flags))
+		ext_flags |= 1 << NFEA_LOCKED;
 
 	if (nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->key.addr))
 		goto nla_put_failure;
 	if (nla_put_u32(skb, NDA_MASTER, br->dev->ifindex))
 		goto nla_put_failure;
+	if (nla_put_u8(skb, NDA_FDB_EXT_ATTRS, ext_flags))
+		goto nla_put_failure;
+
 	ci.ndm_used	 = jiffies_to_clock_t(now - fdb->used);
 	ci.ndm_confirmed = 0;
 	ci.ndm_updated	 = jiffies_to_clock_t(now - fdb->updated);
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index e0c13fcc50ed..897908484b18 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -75,6 +75,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
 	struct net_bridge_mcast *brmctx;
 	struct net_bridge_vlan *vlan;
 	struct net_bridge *br;
+	unsigned long flags = 0;
 	u16 vid = 0;
 	u8 state;
 
@@ -94,8 +95,16 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
 			br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);
 
 		if (!fdb_src || READ_ONCE(fdb_src->dst) != p ||
-		    test_bit(BR_FDB_LOCAL, &fdb_src->flags))
+		    test_bit(BR_FDB_LOCAL, &fdb_src->flags)) {
+			if (!fdb_src) {
+				set_bit(BR_FDB_ENTRY_LOCKED, &flags);
+				br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, flags);
+			}
 			goto drop;
+		} else {
+			if (test_bit(BR_FDB_ENTRY_LOCKED, &fdb_src->flags))
+				goto drop;
+		}
 	}
 
 	nbp_switchdev_frame_mark(p, skb);
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 48bc61ebc211..f5a0b68c4857 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -248,7 +248,8 @@ enum {
 	BR_FDB_ADDED_BY_EXT_LEARN,
 	BR_FDB_OFFLOADED,
 	BR_FDB_NOTIFY,
-	BR_FDB_NOTIFY_INACTIVE
+	BR_FDB_NOTIFY_INACTIVE,
+	BR_FDB_ENTRY_LOCKED,
 };
 
 struct net_bridge_fdb_key {
-- 
2.30.2