bridge: Add flag to control mac learning.

Allow user to control whether mac learning is enabled on the port.
By default, mac learning is enabled.  Disabling mac learning will
cause new dynamic FDB entries to not be created for a particular port.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 14 insertions, 4 deletions

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index b05823cae784..8643809d8417 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -221,6 +221,7 @@ enum {
         IFLA_BRPORT_GUARD,      /* bpdu guard              */
         IFLA_BRPORT_PROTECT,    /* root port protection    */
         IFLA_BRPORT_FAST_LEAVE, /* multicast fast leave    */
+        IFLA_BRPORT_LEARNING,   /* mac learning */
         __IFLA_BRPORT_MAX
 };
 #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 4cdba60926ff..2c08911df578 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -221,7 +221,7 @@ static struct net_bridge_port *new_nbp(struct net_bridge *br,
         p->path_cost = port_cost(dev);
         p->priority = 0x8000 >> BR_PORT_BITS;
         p->port_no = index;
-        p->flags = 0;
+        p->flags = BR_LEARNING;
         br_init_port(p);
         p->state = BR_STATE_DISABLED;
         br_stp_port_timer_init(p);
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 828e2bcc1f52..7e993667d4bf 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -75,7 +75,8 @@ int br_handle_frame_finish(struct sk_buff *skb)
 
         /* insert into forwarding database after filtering to avoid spoofing */
         br = p->br;
-        br_fdb_update(br, p, eth_hdr(skb)->h_source, vid);
+        if (p->flags & BR_LEARNING)
+                br_fdb_update(br, p, eth_hdr(skb)->h_source, vid);
 
         if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) &&
             br_multicast_rcv(br, p, skb))
@@ -142,7 +143,8 @@ static int br_handle_local_finish(struct sk_buff *skb)
         u16 vid = 0;
 
         br_vlan_get_tag(skb, &vid);
-        br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid);
+        if (p->flags & BR_LEARNING)
+                br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid);
         return 0;        /* process further */
 }
 
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 8e3abf564798..ce902bf8a618 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -30,6 +30,7 @@ static inline size_t br_port_info_size(void)
                 + nla_total_size(1)     /* IFLA_BRPORT_GUARD */
                 + nla_total_size(1)     /* IFLA_BRPORT_PROTECT */
                 + nla_total_size(1)     /* IFLA_BRPORT_FAST_LEAVE */
+                + nla_total_size(1)     /* IFLA_BRPORT_LEARNING */
                 + 0;
 }
 
@@ -56,7 +57,8 @@ static int br_port_fill_attrs(struct sk_buff *skb,
             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_PROTECT, !!(p->flags & BR_ROOT_BLOCK)) ||
-            nla_put_u8(skb, IFLA_BRPORT_FAST_LEAVE, !!(p->flags & BR_MULTICAST_FAST_LEAVE)))
+            nla_put_u8(skb, IFLA_BRPORT_FAST_LEAVE, !!(p->flags & BR_MULTICAST_FAST_LEAVE)) ||
+            nla_put_u8(skb, IFLA_BRPORT_LEARNING, !!(p->flags & BR_LEARNING)))
                 return -EMSGSIZE;
 
         return 0;
@@ -281,6 +283,7 @@ static const struct nla_policy ifla_brport_policy[IFLA_BRPORT_MAX + 1] = {
         [IFLA_BRPORT_MODE]      = { .type = NLA_U8 },
         [IFLA_BRPORT_GUARD]     = { .type = NLA_U8 },
         [IFLA_BRPORT_PROTECT]   = { .type = NLA_U8 },
+        [IFLA_BRPORT_LEARNING]  = { .type = NLA_U8 },
 };
 
 /* Change the state of the port and notify spanning tree */
@@ -328,6 +331,7 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[])
         br_set_port_flag(p, tb, IFLA_BRPORT_GUARD, BR_BPDU_GUARD);
         br_set_port_flag(p, tb, IFLA_BRPORT_FAST_LEAVE, BR_MULTICAST_FAST_LEAVE);
         br_set_port_flag(p, tb, IFLA_BRPORT_PROTECT, BR_ROOT_BLOCK);
+        br_set_port_flag(p, tb, IFLA_BRPORT_LEARNING, BR_LEARNING);
 
         if (tb[IFLA_BRPORT_COST]) {
                 err = br_stp_set_path_cost(p, nla_get_u32(tb[IFLA_BRPORT_COST]));
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 1b0ac95a5c37..04d7f43508f7 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -158,6 +158,7 @@ struct net_bridge_port
 #define BR_ROOT_BLOCK           0x00000004
 #define BR_MULTICAST_FAST_LEAVE 0x00000008
 #define BR_ADMIN_COST           0x00000010
+#define BR_LEARNING             0x00000020
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
         u32                             multicast_startup_queries_sent;
diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
index a1ef1b6e14dc..707f3628e9cd 100644
--- a/net/bridge/br_sysfs_if.c
+++ b/net/bridge/br_sysfs_if.c
@@ -158,6 +158,7 @@ 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);
+BRPORT_ATTR_FLAG(learning, BR_LEARNING);
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 static ssize_t show_multicast_router(struct net_bridge_port *p, char *buf)
@@ -195,6 +196,7 @@ static const struct brport_attribute *brport_attrs[] = {
         &brport_attr_hairpin_mode,
         &brport_attr_bpdu_guard,
         &brport_attr_root_block,
+        &brport_attr_learning,
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
         &brport_attr_multicast_router,
         &brport_attr_multicast_fast_leave,