4 files changed, 28 insertions, 2 deletions
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index c331e28c7880..65429b99a2a3 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -27,6 +27,7 @@ static inline size_t br_port_info_size(void)
 		+ nla_total_size(4)	/* IFLA_BRPORT_COST */
 		+ nla_total_size(1)	/* IFLA_BRPORT_MODE */
 		+ nla_total_size(1)	/* IFLA_BRPORT_GUARD */
+		+ nla_total_size(1)	/* IFLA_BRPORT_PROTECT */
 		+ 0;
 }
 
@@ -51,7 +52,8 @@ static int br_port_fill_attrs(struct sk_buff *skb,
 	    nla_put_u16(skb, IFLA_BRPORT_PRIORITY, p->priority) ||
 	    nla_put_u32(skb, IFLA_BRPORT_COST, p->path_cost) ||
 	    nla_put_u8(skb, IFLA_BRPORT_MODE, mode) ||
-	    nla_put_u8(skb, IFLA_BRPORT_GUARD, !!(p->flags & BR_BPDU_GUARD)))
+	    nla_put_u8(skb, IFLA_BRPORT_GUARD, !!(p->flags & BR_BPDU_GUARD)) ||
+	    nla_put_u8(skb, IFLA_BRPORT_PROTECT, !!(p->flags & BR_ROOT_BLOCK)))
 		return -EMSGSIZE;
 
 	return 0;
@@ -165,6 +167,7 @@ static const struct nla_policy ifla_brport_policy[IFLA_BRPORT_MAX + 1] = {
 	[IFLA_BRPORT_PRIORITY]	= { .type = NLA_U16 },
 	[IFLA_BRPORT_MODE]	= { .type = NLA_U8 },
 	[IFLA_BRPORT_GUARD]	= { .type = NLA_U8 },
+	[IFLA_BRPORT_PROTECT]	= { .type = NLA_U8 },
 };
 
 /* Change the state of the port and notify spanning tree */
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index c92b0804ff2d..eb9cd42146a5 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -136,6 +136,7 @@ struct net_bridge_port
 	unsigned long 			flags;
 #define BR_HAIRPIN_MODE		0x00000001
 #define BR_BPDU_GUARD           0x00000002
+#define BR_ROOT_BLOCK		0x00000004
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 	u32				multicast_startup_queries_sent;
diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
index af9a12099ba4..b01849a74310 100644
--- a/net/bridge/br_stp.c
+++ b/net/bridge/br_stp.c
@@ -100,6 +100,21 @@ static int br_should_become_root_port(const struct net_bridge_port *p,
 	return 0;
 }
 
+static void br_root_port_block(const struct net_bridge *br,
+			       struct net_bridge_port *p)
+{
+
+	br_notice(br, "port %u(%s) tried to become root port (blocked)",
+		  (unsigned int) p->port_no, p->dev->name);
+
+	p->state = BR_STATE_LISTENING;
+	br_log_state(p);
+	br_ifinfo_notify(RTM_NEWLINK, p);
+
+	if (br->forward_delay > 0)
+		mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
+}
+
 /* called under bridge lock */
 static void br_root_selection(struct net_bridge *br)
 {
@@ -107,7 +122,12 @@ static void br_root_selection(struct net_bridge *br)
 	u16 root_port = 0;
 
 	list_for_each_entry(p, &br->port_list, list) {
-		if (br_should_become_root_port(p, root_port))
+		if (!br_should_become_root_port(p, root_port))
+			continue;
+
+		if (p->flags & BR_ROOT_BLOCK)
+			br_root_port_block(br, p);
+		else
 			root_port = p->port_no;
 	}
 
diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
index d1dfa4026185..80a4fc5d96ab 100644
--- a/net/bridge/br_sysfs_if.c
+++ b/net/bridge/br_sysfs_if.c
@@ -157,6 +157,7 @@ static BRPORT_ATTR(flush, S_IWUSR, NULL, store_flush);
 
 BRPORT_ATTR_FLAG(hairpin_mode, BR_HAIRPIN_MODE);
 BRPORT_ATTR_FLAG(bpdu_guard, BR_BPDU_GUARD);
+BRPORT_ATTR_FLAG(root_block, BR_ROOT_BLOCK);
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 static ssize_t show_multicast_router(struct net_bridge_port *p, char *buf)
@@ -191,6 +192,7 @@ static const struct brport_attribute *brport_attrs[] = {
 	&brport_attr_flush,
 	&brport_attr_hairpin_mode,
 	&brport_attr_bpdu_guard,
+	&brport_attr_root_block,
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 	&brport_attr_multicast_router,
 #endif