Bluetooth: 6lowpan: search for destination address in all peers

BugLink: https://bugs.launchpad.net/bugs/1839036
[ Upstream commit b188b03270b7f8568fc714101ce82fbf5e811c5a ]

Handle overlooked case where the target address is assigned to a peer
and neither route nor gateway exist.

For one peer, no checks are performed to see if it is meant to receive
packets for a given address.

As soon as there is a second peer however, checks are performed
to deal with routes and gateways for handling complex setups with
multiple hops to a target address.
This logic assumed that no route and no gateway imply that the
destination address can not be reached, which is false in case of a
direct peer.

Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Tested-by: Michael Scott <mike@foundries.io>
Signed-off-by: Josua Mayer <josua.mayer@jm0.eu>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 4e2576fc0c59932cbb1f3c98c150764b91bb52c1..357475cceec61ba264fd49621e75de624f4afff4 100644 (file)
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -187,10 +187,16 @@ static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_btle_dev *dev,
        }
 
        if (!rt) {
-               nexthop = &lowpan_cb(skb)->gw;
-
-               if (ipv6_addr_any(nexthop))
-                       return NULL;
+               if (ipv6_addr_any(&lowpan_cb(skb)->gw)) {
+                       /* There is neither route nor gateway,
+                        * probably the destination is a direct peer.
+                        */
+                       nexthop = daddr;
+               } else {
+                       /* There is a known gateway
+                        */
+                       nexthop = &lowpan_cb(skb)->gw;
+               }
        } else {
                nexthop = rt6_nexthop(rt, daddr);