bridge: Add multicast_router sysfs entries

This patch allows the user to forcibly enable/disable ports as
having multicast routers attached.  A port with a multicast router
will receive all multicast traffic.

The value 0 disables it completely.  The default is 1 which lets
the system automatically detect the presence of routers (currently
this is limited to picking up queries), and 2 means that the port
will always receive all multicast traffic.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 133 insertions, 14 deletions

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 746b5a611aae..674224b6729d 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -746,12 +746,30 @@ static int br_multicast_igmp3_report(struct net_bridge *br,
         return err;
 }
 
+static void br_multicast_add_router(struct net_bridge *br,
+                                    struct net_bridge_port *port)
+{
+        struct hlist_node *p;
+        struct hlist_node **h;
+
+        for (h = &br->router_list.first;
+             (p = *h) &&
+             (unsigned long)container_of(p, struct net_bridge_port, rlist) >
+             (unsigned long)port;
+             h = &p->next)
+                ;
+
+        port->rlist.pprev = h;
+        port->rlist.next = p;
+        rcu_assign_pointer(*h, &port->rlist);
+        if (p)
+                p->pprev = &port->rlist.next;
+}
+
 static void br_multicast_mark_router(struct net_bridge *br,
                                      struct net_bridge_port *port)
 {
         unsigned long now = jiffies;
-        struct hlist_node *p;
-        struct hlist_node **h;
 
         if (!port) {
                 if (br->multicast_router == 1)
@@ -766,18 +784,7 @@ static void br_multicast_mark_router(struct net_bridge *br,
         if (!hlist_unhashed(&port->rlist))
                 goto timer;
 
-        for (h = &br->router_list.first;
-             (p = *h) &&
-             (unsigned long)container_of(p, struct net_bridge_port, rlist) >
-             (unsigned long)port;
-             h = &p->next)
-                ;
-
-        port->rlist.pprev = h;
-        port->rlist.next = p;
-        rcu_assign_pointer(*h, &port->rlist);
-        if (p)
-                p->pprev = &port->rlist.next;
+        br_multicast_add_router(br, port);
 
 timer:
         mod_timer(&port->multicast_router_timer,
@@ -1133,3 +1140,73 @@ void br_multicast_stop(struct net_bridge *br)
 out:
         spin_unlock_bh(&br->multicast_lock);
 }
+
+int br_multicast_set_router(struct net_bridge *br, unsigned long val)
+{
+        int err = -ENOENT;
+
+        spin_lock_bh(&br->multicast_lock);
+        if (!netif_running(br->dev))
+                goto unlock;
+
+        switch (val) {
+        case 0:
+        case 2:
+                del_timer(&br->multicast_router_timer);
+                /* fall through */
+        case 1:
+                br->multicast_router = val;
+                err = 0;
+                break;
+
+        default:
+                err = -EINVAL;
+                break;
+        }
+
+unlock:
+        spin_unlock_bh(&br->multicast_lock);
+
+        return err;
+}
+
+int br_multicast_set_port_router(struct net_bridge_port *p, unsigned long val)
+{
+        struct net_bridge *br = p->br;
+        int err = -ENOENT;
+
+        spin_lock(&br->multicast_lock);
+        if (!netif_running(br->dev) || p->state == BR_STATE_DISABLED)
+                goto unlock;
+
+        switch (val) {
+        case 0:
+        case 1:
+        case 2:
+                p->multicast_router = val;
+                err = 0;
+
+                if (val < 2 && !hlist_unhashed(&p->rlist))
+                        hlist_del_init_rcu(&p->rlist);
+
+                if (val == 1)
+                        break;
+
+                del_timer(&p->multicast_router_timer);
+
+                if (val == 0)
+                        break;
+
+                br_multicast_add_router(br, p);
+                break;
+
+        default:
+                err = -EINVAL;
+                break;
+        }
+
+unlock:
+        spin_unlock(&br->multicast_lock);
+
+        return err;
+}
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index c85943c2b23f..dcdfafbe4b17 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -297,6 +297,9 @@ extern void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
                                  struct sk_buff *skb);
 extern void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
                                  struct sk_buff *skb, struct sk_buff *skb2);
+extern int br_multicast_set_router(struct net_bridge *br, unsigned long val);
+extern int br_multicast_set_port_router(struct net_bridge_port *p,
+                                        unsigned long val);
 #else
 static inline int br_multicast_rcv(struct net_bridge *br,
                                    struct net_bridge_port *port,
diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
index bee4f300d0c8..cb742016db21 100644
--- a/net/bridge/br_sysfs_br.c
+++ b/net/bridge/br_sysfs_br.c
@@ -345,6 +345,24 @@ static ssize_t store_flush(struct device *d,
 }
 static DEVICE_ATTR(flush, S_IWUSR, NULL, store_flush);
 
+#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
+static ssize_t show_multicast_router(struct device *d,
+                                     struct device_attribute *attr, char *buf)
+{
+        struct net_bridge *br = to_bridge(d);
+        return sprintf(buf, "%d\n", br->multicast_router);
+}
+
+static ssize_t store_multicast_router(struct device *d,
+                                      struct device_attribute *attr,
+                                      const char *buf, size_t len)
+{
+        return store_bridge_parm(d, buf, len, br_multicast_set_router);
+}
+static DEVICE_ATTR(multicast_router, S_IRUGO | S_IWUSR, show_multicast_router,
+                   store_multicast_router);
+#endif
+
 static struct attribute *bridge_attrs[] = {
         &dev_attr_forward_delay.attr,
         &dev_attr_hello_time.attr,
@@ -364,6 +382,9 @@ static struct attribute *bridge_attrs[] = {
         &dev_attr_gc_timer.attr,
         &dev_attr_group_addr.attr,
         &dev_attr_flush.attr,
+#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
+        &dev_attr_multicast_router.attr,
+#endif
         NULL
 };
 
diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
index 820643a3ba9c..696596cd3384 100644
--- a/net/bridge/br_sysfs_if.c
+++ b/net/bridge/br_sysfs_if.c
@@ -159,6 +159,21 @@ static ssize_t store_hairpin_mode(struct net_bridge_port *p, unsigned long v)
 static BRPORT_ATTR(hairpin_mode, S_IRUGO | S_IWUSR,
                    show_hairpin_mode, store_hairpin_mode);
 
+#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
+static ssize_t show_multicast_router(struct net_bridge_port *p, char *buf)
+{
+        return sprintf(buf, "%d\n", p->multicast_router);
+}
+
+static ssize_t store_multicast_router(struct net_bridge_port *p,
+                                      unsigned long v)
+{
+        return br_multicast_set_port_router(p, v);
+}
+static BRPORT_ATTR(multicast_router, S_IRUGO | S_IWUSR, show_multicast_router,
+                   store_multicast_router);
+#endif
+
 static struct brport_attribute *brport_attrs[] = {
         &brport_attr_path_cost,
         &brport_attr_priority,
@@ -176,6 +191,9 @@ static struct brport_attribute *brport_attrs[] = {
         &brport_attr_hold_timer,
         &brport_attr_flush,
         &brport_attr_hairpin_mode,
+#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
+        &brport_attr_multicast_router,
+#endif
         NULL
 };