bridge: allow updating existing fdb entries

Need to allow application to update existing fdb entries that already
exist. This makes bridge netlink neighbor API have same flags and
semantics as ip neighbor table.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_fdb.c

@@ -558,19 +558,28 @@ int br_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb)
 
 /* Create new static fdb entry */
 static int fdb_add_entry(struct net_bridge_port *source, const __u8 *addr,
-			 __u16 state)
+			 __u16 state, __u16 flags)
 {
 	struct net_bridge *br = source->br;
 	struct hlist_head *head = &br->hash[br_mac_hash(addr)];
 	struct net_bridge_fdb_entry *fdb;
 
 	fdb = fdb_find(head, addr);
-	if (fdb)
-		return -EEXIST;
+	if (fdb == NULL) {
+		if (!(flags & NLM_F_CREATE))
+			return -ENOENT;
 
-	fdb = fdb_create(head, source, addr);
-	if (!fdb)
-		return -ENOMEM;
+		fdb = fdb_create(head, source, addr);
+		if (!fdb)
+			return -ENOMEM;
+	} else {
+		if (flags & NLM_F_EXCL)
+			return -EEXIST;
+
+		if (flags & NLM_F_REPLACE)
+			fdb->updated = fdb->used = jiffies;
+		fdb->is_local = fdb->is_static = 0;
+	}
 
 	if (state & NUD_PERMANENT)
 		fdb->is_local = fdb->is_static = 1;
@@ -626,7 +635,7 @@ int br_fdb_add(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 	}
 
 	spin_lock_bh(&p->br->hash_lock);
-	err = fdb_add_entry(p, addr, ndm->ndm_state);
+	err = fdb_add_entry(p, addr, ndm->ndm_state, nlh->nlmsg_flags);
 	spin_unlock_bh(&p->br->hash_lock);
 
 	return err;