bridge: port isolate

Isolating individual bridge ports

Signed-off-by: Felix Fietkau <nbd@nbd.name>

include/linux/if_bridge.h

@@ -47,6 +47,7 @@ struct br_ip_list {
 #define BR_PROXYARP_WIFI	BIT(10)
 #define BR_MCAST_FLOOD		BIT(11)
 #define BR_MULTICAST_TO_UNICAST	BIT(12)
+#define BR_ISOLATE_MODE		BIT(13)
 
 #define BR_DEFAULT_AGEING_TIME	(300 * HZ)
 

net/bridge/br_forward.c

@@ -162,6 +162,9 @@ static int deliver_clone(const struct net_bridge_port *prev,
 void br_forward(const struct net_bridge_port *to,
 		struct sk_buff *skb, bool local_rcv, bool local_orig)
 {
+	if (to->flags & BR_ISOLATE_MODE)
+		to = NULL;
+
 	if (to && should_deliver(to, skb)) {
 		if (local_rcv)
 			deliver_clone(to, skb, local_orig);
@@ -236,6 +239,8 @@ void br_flood(struct net_bridge *br, struct sk_buff *skb,
 	struct net_bridge_port *p;
 
 	list_for_each_entry_rcu(p, &br->port_list, list) {
+		if (!local_orig && (p->flags & BR_ISOLATE_MODE))
+			continue;
 		/* Do not flood unicast traffic to ports that turn it off */
 		if (pkt_type == BR_PKT_UNICAST && !(p->flags & BR_FLOOD))
 			continue;

net/bridge/br_input.c

@@ -175,6 +175,9 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
 	if (IS_ENABLED(CONFIG_INET) && skb->protocol == htons(ETH_P_ARP))
 		br_do_proxy_arp(skb, br, vid, p);
 
+	if (p->flags & BR_ISOLATE_MODE)
+		return br_pass_frame_up(skb);
+
 	switch (pkt_type) {
 	case BR_PKT_MULTICAST:
 		mdst = br_mdb_get(br, skb, vid);

net/bridge/br_sysfs_if.c

@@ -172,6 +172,7 @@ BRPORT_ATTR_FLAG(unicast_flood, BR_FLOOD);
 BRPORT_ATTR_FLAG(proxyarp, BR_PROXYARP);
 BRPORT_ATTR_FLAG(proxyarp_wifi, BR_PROXYARP_WIFI);
 BRPORT_ATTR_FLAG(multicast_flood, BR_MCAST_FLOOD);
+BRPORT_ATTR_FLAG(isolate_mode, BR_ISOLATE_MODE);
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 static ssize_t show_multicast_router(struct net_bridge_port *p, char *buf)
@@ -220,6 +221,7 @@ static const struct brport_attribute *brport_attrs[] = {
 	&brport_attr_proxyarp,
 	&brport_attr_proxyarp_wifi,
 	&brport_attr_multicast_flood,
+	&brport_attr_isolate_mode,
 	NULL
 };