[B.A.T.M.A.N.] [RFC v3 14/19] batman-adv: Add multicast_mode mesh genl configuration

[Sven Eckelmann <sven@narfation.org>]

The mesh interface can optimize the flooding of multicast packets based on
the content of the global translation tables.

The BATADV_CMD_SET_MESH/BATADV_CMD_GET_MESH commands allow to set/get the
configuration of this feature using the BATADV_ATTR_MULTICAST_MODE
attribute. Setting the u8 to zero will disable this feature and setting it
to something else is enabling this feature.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
Cc: Linus Lüssing <linus.luessing@c0d3.blue>
---
 include/uapi/linux/batman_adv.h |  8 ++++++++
 net/batman-adv/netlink.c        | 15 +++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/include/uapi/linux/batman_adv.h b/include/uapi/linux/batman_adv.h
index efc06449..514acc06 100644
--- a/include/uapi/linux/batman_adv.h
+++ b/include/uapi/linux/batman_adv.h
@@ -454,6 +454,14 @@ enum batadv_nl_attrs {
 	 */
 	BATADV_ATTR_LOG_LEVEL,
 
+	/**
+	 * @BATADV_ATTR_MULTICAST_MODE: whether multicast optimizations are
+	 *  enabled or disabled. If set to zero then all nodes in the mesh are
+	 *  going to use classic flooding for any multicast packet with no
+	 *  optimizations.
+	 */
+	BATADV_ATTR_MULTICAST_MODE,
+
 	/* add attributes above here, update the policy in netlink.c */
 
 	/**
diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c
index 8e3a1b6e..32762003 100644
--- a/net/batman-adv/netlink.c
+++ b/net/batman-adv/netlink.c
@@ -155,6 +155,7 @@ static const struct nla_policy batadv_netlink_policy[NUM_BATADV_ATTR] = {
 	[BATADV_ATTR_GW_SEL_CLASS]		= { .type = NLA_U32 },
 	[BATADV_ATTR_HOP_PENALTY]		= { .type = NLA_U8 },
 	[BATADV_ATTR_LOG_LEVEL]			= { .type = NLA_U32 },
+	[BATADV_ATTR_MULTICAST_MODE]		= { .type = NLA_U8 },
 };
 
 /**
@@ -342,6 +343,12 @@ static int batadv_netlink_mesh_put(struct sk_buff *msg,
 		goto nla_put_failure;
 #endif /* CONFIG_BATMAN_ADV_DEBUG */
 
+#ifdef CONFIG_BATMAN_ADV_MCAST
+	if (nla_put_u8(msg, BATADV_ATTR_MULTICAST_MODE,
+		       !!atomic_read(&bat_priv->multicast_mode)))
+		goto nla_put_failure;
+#endif /* CONFIG_BATMAN_ADV_MCAST */
+
 	batadv_hardif_put(primary_if);
 
 	genlmsg_end(msg, hdr);
@@ -562,6 +569,14 @@ static int batadv_netlink_set_mesh(struct sk_buff *skb, struct genl_info *info)
 	}
 #endif /* CONFIG_BATMAN_ADV_DEBUG */
 
+#ifdef CONFIG_BATMAN_ADV_MCAST
+	if (info->attrs[BATADV_ATTR_MULTICAST_MODE]) {
+		attr = info->attrs[BATADV_ATTR_MULTICAST_MODE];
+
+		atomic_set(&bat_priv->multicast_mode, !!nla_get_u8(attr));
+	}
+#endif /* CONFIG_BATMAN_ADV_MCAST */
+
 	batadv_netlink_notify_mesh(bat_priv);
 
 	return 0;
-- 
2.19.2