bridge: netlink: add support for igmp's hash_elasticity

Add IFLA_BR_MCAST_HASH_ELASTICITY to allow setting/getting
br->hash_elasticity 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

@@ -249,6 +249,7 @@ enum {
 	IFLA_BR_MCAST_SNOOPING,
 	IFLA_BR_MCAST_QUERY_USE_IFADDR,
 	IFLA_BR_MCAST_QUERIER,
+	IFLA_BR_MCAST_HASH_ELASTICITY,
 	__IFLA_BR_MAX,
 };
 

net/bridge/br_netlink.c

@@ -771,6 +771,7 @@ static const struct nla_policy br_policy[IFLA_BR_MAX + 1] = {
 	[IFLA_BR_MCAST_SNOOPING] = { .type = NLA_U8 },
 	[IFLA_BR_MCAST_QUERY_USE_IFADDR] = { .type = NLA_U8 },
 	[IFLA_BR_MCAST_QUERIER] = { .type = NLA_U8 },
+	[IFLA_BR_MCAST_HASH_ELASTICITY] = { .type = NLA_U32 },
 };
 
 static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
@@ -897,6 +898,12 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 		if (err)
 			return err;
 	}
+
+	if (data[IFLA_BR_MCAST_HASH_ELASTICITY]) {
+		u32 val = nla_get_u32(data[IFLA_BR_MCAST_HASH_ELASTICITY]);
+
+		br->hash_elasticity = val;
+	}
 #endif
 
 	return 0;
@@ -931,6 +938,7 @@ static size_t br_get_size(const struct net_device *brdev)
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_SNOOPING */
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_QUERY_USE_IFADDR */
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_QUERIER */
+	       nla_total_size(sizeof(u32)) +     /* IFLA_BR_MCAST_HASH_ELASTICITY */
 #endif
 	       0;
 }
@@ -993,7 +1001,9 @@ static int br_fill_info(struct sk_buff *skb, const struct net_device *brdev)
 	    nla_put_u8(skb, IFLA_BR_MCAST_SNOOPING, !br->multicast_disabled) ||
 	    nla_put_u8(skb, IFLA_BR_MCAST_QUERY_USE_IFADDR,
 		       br->multicast_query_use_ifaddr) ||
-	    nla_put_u8(skb, IFLA_BR_MCAST_QUERIER, br->multicast_querier))
+	    nla_put_u8(skb, IFLA_BR_MCAST_QUERIER, br->multicast_querier) ||
+	    nla_put_u32(skb, IFLA_BR_MCAST_HASH_ELASTICITY,
+			br->hash_elasticity))
 		return -EMSGSIZE;
 #endif