batman-adv: Add network_coding mesh genl configuration

The mesh interface can use (in an homogeneous mesh) network coding, a
mechanism that aims to increase the overall network throughput by fusing
multiple packets in one transmission.

The BATADV_CMD_SET_MESH/BATADV_CMD_GET_MESH commands allow to set/get the
configuration of this feature using the BATADV_ATTR_NETWORK_CODING_ENABLED
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>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

include/uapi/linux/batman_adv.h

@@ -464,6 +464,13 @@ enum batadv_nl_attrs {
 	 */
 	BATADV_ATTR_MULTICAST_FORCEFLOOD_ENABLED,
 
+	/**
+	 * @BATADV_ATTR_NETWORK_CODING_ENABLED: whether Network Coding (using
+	 *  some magic to send fewer wifi packets but still the same content) is
+	 *  enabled or not.
+	 */
+	BATADV_ATTR_NETWORK_CODING_ENABLED,
+
 	/* add attributes above here, update the policy in netlink.c */
 
 	/**

net/batman-adv/netlink.c

@@ -55,6 +55,7 @@
 #include "hard-interface.h"
 #include "log.h"
 #include "multicast.h"
+#include "network-coding.h"
 #include "originator.h"
 #include "soft-interface.h"
 #include "tp_meter.h"
@@ -156,6 +157,7 @@ static const struct nla_policy batadv_netlink_policy[NUM_BATADV_ATTR] = {
 	[BATADV_ATTR_HOP_PENALTY]		= { .type = NLA_U8 },
 	[BATADV_ATTR_LOG_LEVEL]			= { .type = NLA_U32 },
 	[BATADV_ATTR_MULTICAST_FORCEFLOOD_ENABLED]	= { .type = NLA_U8 },
+	[BATADV_ATTR_NETWORK_CODING_ENABLED]	= { .type = NLA_U8 },
 };
 
 /**
@@ -350,6 +352,12 @@ static int batadv_netlink_mesh_fill(struct sk_buff *msg,
 		goto nla_put_failure;
 #endif /* CONFIG_BATMAN_ADV_MCAST */
 
+#ifdef CONFIG_BATMAN_ADV_NC
+	if (nla_put_u8(msg, BATADV_ATTR_NETWORK_CODING_ENABLED,
+		       !!atomic_read(&bat_priv->network_coding)))
+		goto nla_put_failure;
+#endif /* CONFIG_BATMAN_ADV_NC */
+
 	if (primary_if)
 		batadv_hardif_put(primary_if);
 
@@ -579,6 +587,15 @@ static int batadv_netlink_set_mesh(struct sk_buff *skb, struct genl_info *info)
 	}
 #endif /* CONFIG_BATMAN_ADV_MCAST */
 
+#ifdef CONFIG_BATMAN_ADV_NC
+	if (info->attrs[BATADV_ATTR_NETWORK_CODING_ENABLED]) {
+		attr = info->attrs[BATADV_ATTR_NETWORK_CODING_ENABLED];
+
+		atomic_set(&bat_priv->network_coding, !!nla_get_u8(attr));
+		batadv_nc_status_update(bat_priv->soft_iface);
+	}
+#endif /* CONFIG_BATMAN_ADV_NC */
+
 	batadv_netlink_notify_mesh(bat_priv);
 
 	return 0;