6lowpan: add private neighbour data

This patch will introduce a 6lowpan neighbour private data. Like the
interface private data we handle private data for generic 6lowpan and
for link-layer specific 6lowpan.

The current first use case if to save the short address for a 802.15.4
6lowpan neighbour.

Cc: David S. Miller <davem@davemloft.net>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Alexander Aring <aar@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 23 insertions, 2 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d101e4d904ba..36e43bd422f8 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1483,8 +1483,7 @@ enum netdev_priv_flags {
  *      @perm_addr:             Permanent hw address
  *      @addr_assign_type:      Hw address assignment type
  *      @addr_len:              Hardware address length
- *      @neigh_priv_len;        Used in neigh_alloc(),
- *                              initialized only in atm/clip.c
+ *      @neigh_priv_len:        Used in neigh_alloc()
  *      @dev_id:                Used to differentiate devices that share
  *                              the same link layer address
  *      @dev_port:              Used to differentiate devices that share
diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
index da84cf920b78..2d9b9d39221e 100644
--- a/include/net/6lowpan.h
+++ b/include/net/6lowpan.h
@@ -141,6 +141,16 @@ struct lowpan_dev {
         u8 priv[0] __aligned(sizeof(void *));
 };
 
+struct lowpan_802154_neigh {
+        __le16 short_addr;
+};
+
+static inline
+struct lowpan_802154_neigh *lowpan_802154_neigh(void *neigh_priv)
+{
+        return neigh_priv;
+}
+
 static inline
 struct lowpan_dev *lowpan_dev(const struct net_device *dev)
 {
diff --git a/net/ieee802154/6lowpan/core.c b/net/ieee802154/6lowpan/core.c
index 4e2b30894224..8c004a0c8d64 100644
--- a/net/ieee802154/6lowpan/core.c
+++ b/net/ieee802154/6lowpan/core.c
@@ -81,11 +81,21 @@ static int lowpan_stop(struct net_device *dev)
         return 0;
 }
 
+static int lowpan_neigh_construct(struct neighbour *n)
+{
+        struct lowpan_802154_neigh *neigh = lowpan_802154_neigh(neighbour_priv(n));
+
+        /* default no short_addr is available for a neighbour */
+        neigh->short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
+        return 0;
+}
+
 static const struct net_device_ops lowpan_netdev_ops = {
         .ndo_init               = lowpan_dev_init,
         .ndo_start_xmit         = lowpan_xmit,
         .ndo_open               = lowpan_open,
         .ndo_stop               = lowpan_stop,
+        .ndo_neigh_construct    = lowpan_neigh_construct,
 };
 
 static void lowpan_setup(struct net_device *ldev)
@@ -150,6 +160,8 @@ static int lowpan_newlink(struct net *src_net, struct net_device *ldev,
                                 wdev->needed_headroom;
         ldev->needed_tailroom = wdev->needed_tailroom;
 
+        ldev->neigh_priv_len = sizeof(struct lowpan_802154_neigh);
+
         ret = lowpan_register_netdevice(ldev, LOWPAN_LLTYPE_IEEE802154);
         if (ret < 0) {
                 dev_put(wdev);