Merge branch 'net-bridge-fdb-activity-tracking'

Nikolay Aleksandrov says:

====================
net: bridge: fdb activity tracking

This set adds extensions needed for EVPN multi-homing proper and
efficient mac sync. User-space (e.g. FRR) needs to be able to track
non-dynamic entry activity on per-fdb basis depending if a tracked fdb is
currently peer active or locally active and needs to be able to add new
peer active fdb (static + track + inactive) without refreshing it to get
real activity tracking. Patch 02 adds a new NDA attribute - NDA_FDB_EXT_ATTRS
to avoid future pollution of NDA attributes by bridge or vxlan. New
bridge/vxlan specific fdb attributes are embedded in NDA_FDB_EXT_ATTRS,
which is used in patch 03 to pass the new NFEA_ACTIVITY_NOTIFY attribute
which controls if an fdb should be tracked and also reflects its current
state when dumping. It is treated as a bitfield, current valid bits are:
 1 - mark an entry for activity tracking
 2 - mark an entry as inactive to avoid multiple notifications and
     reflect state properly

Patch 04 adds the ability to avoid refreshing an entry when changing it
via the NFEA_DONT_REFRESH flag. That allows user-space to mark a static
entry for tracking and keep its real activity unchanged.
The set has been extensively tested with FRR and those changes will
be upstreamed if/after it gets accepted.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 139 insertions, 17 deletions

diff --git a/include/uapi/linux/neighbour.h b/include/uapi/linux/neighbour.h
index eefcda8ca44e..dc8b72201f6c 100644
--- a/include/uapi/linux/neighbour.h
+++ b/include/uapi/linux/neighbour.h
@@ -30,6 +30,7 @@ enum {
 	NDA_SRC_VNI,
 	NDA_PROTOCOL,  /* Originator of entry */
 	NDA_NH_ID,
+	NDA_FDB_EXT_ATTRS,
 	__NDA_MAX
 };
 
@@ -172,4 +173,27 @@ enum {
 };
 #define NDTA_MAX (__NDTA_MAX - 1)
 
+ /* FDB activity notification bits used in NFEA_ACTIVITY_NOTIFY:
+  * - FDB_NOTIFY_BIT - notify on activity/expire for any entry
+  * - FDB_NOTIFY_INACTIVE_BIT - mark as inactive to avoid multiple notifications
+  */
+enum {
+	FDB_NOTIFY_BIT		= (1 << 0),
+	FDB_NOTIFY_INACTIVE_BIT	= (1 << 1)
+};
+
+/* embedded into NDA_FDB_EXT_ATTRS:
+ * [NDA_FDB_EXT_ATTRS] = {
+ *     [NFEA_ACTIVITY_NOTIFY]
+ *     ...
+ * }
+ */
+enum {
+	NFEA_UNSPEC,
+	NFEA_ACTIVITY_NOTIFY,
+	NFEA_DONT_REFRESH,
+	__NFEA_MAX
+};
+#define NFEA_MAX (__NFEA_MAX - 1)
+
 #endif
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 4877a0db16c6..9db504baa094 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -349,12 +349,21 @@ void br_fdb_cleanup(struct work_struct *work)
 	 */
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(f, &br->fdb_list, fdb_node) {
-		unsigned long this_timer;
+		unsigned long this_timer = f->updated + delay;
 
 		if (test_bit(BR_FDB_STATIC, &f->flags) ||
-		    test_bit(BR_FDB_ADDED_BY_EXT_LEARN, &f->flags))
+		    test_bit(BR_FDB_ADDED_BY_EXT_LEARN, &f->flags)) {
+			if (test_bit(BR_FDB_NOTIFY, &f->flags)) {
+				if (time_after(this_timer, now))
+					work_delay = min(work_delay,
+							 this_timer - now);
+				else if (!test_and_set_bit(BR_FDB_NOTIFY_INACTIVE,
+							   &f->flags))
+					fdb_notify(br, f, RTM_NEWNEIGH, false);
+			}
 			continue;
-		this_timer = f->updated + delay;
+		}
+
 		if (time_after(this_timer, now)) {
 			work_delay = min(work_delay, this_timer - now);
 		} else {
@@ -556,11 +565,17 @@ int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
 	return ret;
 }
 
+/* returns true if the fdb was modified */
+static bool __fdb_mark_active(struct net_bridge_fdb_entry *fdb)
+{
+	return !!(test_bit(BR_FDB_NOTIFY_INACTIVE, &fdb->flags) &&
+		  test_and_clear_bit(BR_FDB_NOTIFY_INACTIVE, &fdb->flags));
+}
+
 void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 		   const unsigned char *addr, u16 vid, unsigned long flags)
 {
 	struct net_bridge_fdb_entry *fdb;
-	bool fdb_modified = false;
 
 	/* some users want to always flood. */
 	if (hold_time(br) == 0)
@@ -575,6 +590,12 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 					source->dev->name, addr, vid);
 		} else {
 			unsigned long now = jiffies;
+			bool fdb_modified = false;
+
+			if (now != fdb->updated) {
+				fdb->updated = now;
+				fdb_modified = __fdb_mark_active(fdb);
+			}
 
 			/* fastpath: update of existing entry */
 			if (unlikely(source != fdb->dst &&
@@ -587,8 +608,7 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 					clear_bit(BR_FDB_ADDED_BY_EXT_LEARN,
 						  &fdb->flags);
 			}
-			if (now != fdb->updated)
-				fdb->updated = now;
+
 			if (unlikely(test_bit(BR_FDB_ADDED_BY_USER, &flags)))
 				set_bit(BR_FDB_ADDED_BY_USER, &fdb->flags);
 			if (unlikely(fdb_modified)) {
@@ -667,6 +687,23 @@ static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
 					&fdb->key.vlan_id))
 		goto nla_put_failure;
 
+	if (test_bit(BR_FDB_NOTIFY, &fdb->flags)) {
+		struct nlattr *nest = nla_nest_start(skb, NDA_FDB_EXT_ATTRS);
+		u8 notify_bits = FDB_NOTIFY_BIT;
+
+		if (!nest)
+			goto nla_put_failure;
+		if (test_bit(BR_FDB_NOTIFY_INACTIVE, &fdb->flags))
+			notify_bits |= FDB_NOTIFY_INACTIVE_BIT;
+
+		if (nla_put_u8(skb, NFEA_ACTIVITY_NOTIFY, notify_bits)) {
+			nla_nest_cancel(skb, nest);
+			goto nla_put_failure;
+		}
+
+		nla_nest_end(skb, nest);
+	}
+
 	nlmsg_end(skb, nlh);
 	return 0;
 
@@ -681,7 +718,9 @@ static inline size_t fdb_nlmsg_size(void)
 		+ nla_total_size(ETH_ALEN) /* NDA_LLADDR */
 		+ nla_total_size(sizeof(u32)) /* NDA_MASTER */
 		+ nla_total_size(sizeof(u16)) /* NDA_VLAN */
-		+ nla_total_size(sizeof(struct nda_cacheinfo));
+		+ nla_total_size(sizeof(struct nda_cacheinfo))
+		+ nla_total_size(0) /* NDA_FDB_EXT_ATTRS */
+		+ nla_total_size(sizeof(u8)); /* NFEA_ACTIVITY_NOTIFY */
 }
 
 static void fdb_notify(struct net_bridge *br,
@@ -791,14 +830,41 @@ errout:
 	return err;
 }
 
+/* returns true if the fdb is modified */
+static bool fdb_handle_notify(struct net_bridge_fdb_entry *fdb, u8 notify)
+{
+	bool modified = false;
+
+	/* allow to mark an entry as inactive, usually done on creation */
+	if ((notify & FDB_NOTIFY_INACTIVE_BIT) &&
+	    !test_and_set_bit(BR_FDB_NOTIFY_INACTIVE, &fdb->flags))
+		modified = true;
+
+	if ((notify & FDB_NOTIFY_BIT) &&
+	    !test_and_set_bit(BR_FDB_NOTIFY, &fdb->flags)) {
+		/* enabled activity tracking */
+		modified = true;
+	} else if (!(notify & FDB_NOTIFY_BIT) &&
+		   test_and_clear_bit(BR_FDB_NOTIFY, &fdb->flags)) {
+		/* disabled activity tracking, clear notify state */
+		clear_bit(BR_FDB_NOTIFY_INACTIVE, &fdb->flags);
+		modified = true;
+	}
+
+	return modified;
+}
+
 /* Update (create or replace) forwarding database entry */
 static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source,
-			 const u8 *addr, u16 state, u16 flags, u16 vid,
-			 u8 ndm_flags)
+			 const u8 *addr, struct ndmsg *ndm, u16 flags, u16 vid,
+			 struct nlattr *nfea_tb[])
 {
-	bool is_sticky = !!(ndm_flags & NTF_STICKY);
+	bool is_sticky = !!(ndm->ndm_flags & NTF_STICKY);
+	bool refresh = !nfea_tb[NFEA_DONT_REFRESH];
 	struct net_bridge_fdb_entry *fdb;
+	u16 state = ndm->ndm_state;
 	bool modified = false;
+	u8 notify = 0;
 
 	/* If the port cannot learn allow only local and static entries */
 	if (source && !(state & NUD_PERMANENT) && !(state & NUD_NOARP) &&
@@ -815,6 +881,13 @@ static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source,
 	if (is_sticky && (state & NUD_PERMANENT))
 		return -EINVAL;
 
+	if (nfea_tb[NFEA_ACTIVITY_NOTIFY]) {
+		notify = nla_get_u8(nfea_tb[NFEA_ACTIVITY_NOTIFY]);
+		if ((notify & ~BR_FDB_NOTIFY_SETTABLE_BITS) ||
+		    (notify & BR_FDB_NOTIFY_SETTABLE_BITS) == FDB_NOTIFY_INACTIVE_BIT)
+			return -EINVAL;
+	}
+
 	fdb = br_fdb_find(br, addr, vid);
 	if (fdb == NULL) {
 		if (!(flags & NLM_F_CREATE))
@@ -858,11 +931,15 @@ static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source,
 		modified = true;
 	}
 
+	if (fdb_handle_notify(fdb, notify))
+		modified = true;
+
 	set_bit(BR_FDB_ADDED_BY_USER, &fdb->flags);
 
 	fdb->used = jiffies;
 	if (modified) {
-		fdb->updated = jiffies;
+		if (refresh)
+			fdb->updated = jiffies;
 		fdb_notify(br, fdb, RTM_NEWNEIGH, true);
 	}
 
@@ -871,7 +948,7 @@ static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source,
 
 static int __br_fdb_add(struct ndmsg *ndm, struct net_bridge *br,
 			struct net_bridge_port *p, const unsigned char *addr,
-			u16 nlh_flags, u16 vid)
+			u16 nlh_flags, u16 vid, struct nlattr *nfea_tb[])
 {
 	int err = 0;
 
@@ -893,20 +970,25 @@ static int __br_fdb_add(struct ndmsg *ndm, struct net_bridge *br,
 		err = br_fdb_external_learn_add(br, p, addr, vid, true);
 	} else {
 		spin_lock_bh(&br->hash_lock);
-		err = fdb_add_entry(br, p, addr, ndm->ndm_state,
-				    nlh_flags, vid, ndm->ndm_flags);
+		err = fdb_add_entry(br, p, addr, ndm, nlh_flags, vid, nfea_tb);
 		spin_unlock_bh(&br->hash_lock);
 	}
 
 	return err;
 }
 
+static const struct nla_policy br_nda_fdb_pol[NFEA_MAX + 1] = {
+	[NFEA_ACTIVITY_NOTIFY]	= { .type = NLA_U8 },
+	[NFEA_DONT_REFRESH]	= { .type = NLA_FLAG },
+};
+
 /* Add new permanent fdb entry with RTM_NEWNEIGH */
 int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
 	       struct net_device *dev,
 	       const unsigned char *addr, u16 vid, u16 nlh_flags,
 	       struct netlink_ext_ack *extack)
 {
+	struct nlattr *nfea_tb[NFEA_MAX + 1], *attr;
 	struct net_bridge_vlan_group *vg;
 	struct net_bridge_port *p = NULL;
 	struct net_bridge_vlan *v;
@@ -939,6 +1021,16 @@ int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
 		vg = nbp_vlan_group(p);
 	}
 
+	if (tb[NDA_FDB_EXT_ATTRS]) {
+		attr = tb[NDA_FDB_EXT_ATTRS];
+		err = nla_parse_nested(nfea_tb, NFEA_MAX, attr,
+				       br_nda_fdb_pol, extack);
+		if (err)
+			return err;
+	} else {
+		memset(nfea_tb, 0, sizeof(struct nlattr *) * (NFEA_MAX + 1));
+	}
+
 	if (vid) {
 		v = br_vlan_find(vg, vid);
 		if (!v || !br_vlan_should_use(v)) {
@@ -947,9 +1039,9 @@ int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
 		}
 
 		/* VID was specified, so use it. */
-		err = __br_fdb_add(ndm, br, p, addr, nlh_flags, vid);
+		err = __br_fdb_add(ndm, br, p, addr, nlh_flags, vid, nfea_tb);
 	} else {
-		err = __br_fdb_add(ndm, br, p, addr, nlh_flags, 0);
+		err = __br_fdb_add(ndm, br, p, addr, nlh_flags, 0, nfea_tb);
 		if (err || !vg || !vg->num_vlans)
 			goto out;
 
@@ -960,7 +1052,8 @@ int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
 		list_for_each_entry(v, &vg->vlan_list, vlist) {
 			if (!br_vlan_should_use(v))
 				continue;
-			err = __br_fdb_add(ndm, br, p, addr, nlh_flags, v->vid);
+			err = __br_fdb_add(ndm, br, p, addr, nlh_flags, v->vid,
+					   nfea_tb);
 			if (err)
 				goto out;
 		}
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 7501be4eeba0..c0ae639e1b36 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -48,6 +48,8 @@ enum {
 /* Path to usermode spanning tree program */
 #define BR_STP_PROG	"/sbin/bridge-stp"
 
+#define BR_FDB_NOTIFY_SETTABLE_BITS (FDB_NOTIFY_BIT | FDB_NOTIFY_INACTIVE_BIT)
+
 typedef struct bridge_id bridge_id;
 typedef struct mac_addr mac_addr;
 typedef __u16 port_id;
@@ -184,6 +186,8 @@ enum {
 	BR_FDB_ADDED_BY_USER,
 	BR_FDB_ADDED_BY_EXT_LEARN,
 	BR_FDB_OFFLOADED,
+	BR_FDB_NOTIFY,
+	BR_FDB_NOTIFY_INACTIVE
 };
 
 struct net_bridge_fdb_key {
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index ef6b5a8f629c..8e39e28b0a8d 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1783,6 +1783,7 @@ const struct nla_policy nda_policy[NDA_MAX+1] = {
 	[NDA_MASTER]		= { .type = NLA_U32 },
 	[NDA_PROTOCOL]		= { .type = NLA_U8 },
 	[NDA_NH_ID]		= { .type = NLA_U32 },
+	[NDA_FDB_EXT_ATTRS]	= { .type = NLA_NESTED },
 };
 
 static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh,