bridge: netlink: add group_addr support

Add IFLA_BR_GROUP_ADDR attribute to allow setting and retrieving the
group_addr via netlink.
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/if_link.h

@@ -243,6 +243,7 @@ enum {
 	IFLA_BR_TCN_TIMER,
 	IFLA_BR_TOPOLOGY_CHANGE_TIMER,
 	IFLA_BR_GC_TIMER,
+	IFLA_BR_GROUP_ADDR,
 	__IFLA_BR_MAX,
 };
 

net/bridge/br_netlink.c

@@ -765,6 +765,8 @@ static const struct nla_policy br_policy[IFLA_BR_MAX + 1] = {
 	[IFLA_BR_VLAN_FILTERING] = { .type = NLA_U8 },
 	[IFLA_BR_VLAN_PROTOCOL] = { .type = NLA_U16 },
 	[IFLA_BR_GROUP_FWD_MASK] = { .type = NLA_U16 },
+	[IFLA_BR_GROUP_ADDR] = { .type = NLA_BINARY,
+				 .len  = ETH_ALEN },
 };
 
 static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
@@ -838,6 +840,25 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 		br->group_fwd_mask = fwd_mask;
 	}
 
+	if (data[IFLA_BR_GROUP_ADDR]) {
+		u8 new_addr[ETH_ALEN];
+
+		if (nla_len(data[IFLA_BR_GROUP_ADDR]) != ETH_ALEN)
+			return -EINVAL;
+		memcpy(new_addr, nla_data(data[IFLA_BR_GROUP_ADDR]), ETH_ALEN);
+		if (!is_link_local_ether_addr(new_addr))
+			return -EINVAL;
+		if (new_addr[5] == 1 ||		/* 802.3x Pause address */
+		    new_addr[5] == 2 ||		/* 802.3ad Slow protocols */
+		    new_addr[5] == 3)		/* 802.1X PAE address */
+			return -EINVAL;
+		spin_lock_bh(&br->lock);
+		memcpy(br->group_addr, new_addr, sizeof(br->group_addr));
+		spin_unlock_bh(&br->lock);
+		br->group_addr_set = true;
+		br_recalculate_fwd_mask(br);
+	}
+
 	return 0;
 }
 
@@ -864,6 +885,7 @@ static size_t br_get_size(const struct net_device *brdev)
 	       nla_total_size(sizeof(u64)) +    /* IFLA_BR_TCN_TIMER */
 	       nla_total_size(sizeof(u64)) +    /* IFLA_BR_TOPOLOGY_CHANGE_TIMER */
 	       nla_total_size(sizeof(u64)) +    /* IFLA_BR_GC_TIMER */
+	       nla_total_size(ETH_ALEN) +       /* IFLA_BR_GROUP_ADDR */
 	       0;
 }
 
@@ -911,7 +933,8 @@ static int br_fill_info(struct sk_buff *skb, const struct net_device *brdev)
 	    nla_put_u64(skb, IFLA_BR_TCN_TIMER, tcn_timer) ||
 	    nla_put_u64(skb, IFLA_BR_TOPOLOGY_CHANGE_TIMER,
 			topology_change_timer) ||
-	    nla_put_u64(skb, IFLA_BR_GC_TIMER, gc_timer))
+	    nla_put_u64(skb, IFLA_BR_GC_TIMER, gc_timer) ||
+	    nla_put(skb, IFLA_BR_GROUP_ADDR, ETH_ALEN, br->group_addr))
 		return -EMSGSIZE;
 
 #ifdef CONFIG_BRIDGE_VLAN_FILTERING