ieee820154: add max frame retries setting support

This patch add support for setting mac frame retries setting via
nl802154 framework.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index af38355..0e272c6 100644
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -667,6 +667,30 @@
 	return rdev_set_max_csma_backoffs(rdev, wpan_dev, max_csma_backoffs);
 }
 
+static int
+nl802154_set_max_frame_retries(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg802154_registered_device *rdev = info->user_ptr[0];
+	struct net_device *dev = info->user_ptr[1];
+	struct wpan_dev *wpan_dev = dev->ieee802154_ptr;
+	s8 max_frame_retries;
+
+	if (netif_running(dev))
+		return -EBUSY;
+
+	if (!info->attrs[NL802154_ATTR_MAX_FRAME_RETRIES])
+		return -EINVAL;
+
+	max_frame_retries = nla_get_s8(
+			info->attrs[NL802154_ATTR_MAX_FRAME_RETRIES]);
+
+	/* check 802.15.4 constraints */
+	if (max_frame_retries < -1 || max_frame_retries > 7)
+		return -EINVAL;
+
+	return rdev_set_max_frame_retries(rdev, wpan_dev, max_frame_retries);
+}
+
 #define NL802154_FLAG_NEED_WPAN_PHY	0x01
 #define NL802154_FLAG_NEED_NETDEV	0x02
 #define NL802154_FLAG_NEED_RTNL		0x04
@@ -817,6 +841,14 @@
 		.internal_flags = NL802154_FLAG_NEED_NETDEV |
 				  NL802154_FLAG_NEED_RTNL,
 	},
+	{
+		.cmd = NL802154_CMD_SET_MAX_FRAME_RETRIES,
+		.doit = nl802154_set_max_frame_retries,
+		.policy = nl802154_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL802154_FLAG_NEED_NETDEV |
+				  NL802154_FLAG_NEED_RTNL,
+	},
 };
 
 /* initialisation/exit functions */