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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Jukka Rissanen <jukka.rissanen@linux.intel.com>,
        Michael Scott <mike@foundries.io>,
        Josua Mayer <josua.mayer@jm0.eu>,
        Marcel Holtmann <marcel@holtmann.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 097/293] Bluetooth: 6lowpan: search for destination address in all peers
Date:   Mon, 29 Jul 2019 21:19:48 +0200
Message-Id: <20190729190832.052222758@linuxfoundation.org>
In-Reply-To: <20190729190820.321094988@linuxfoundation.org>
References: <20190729190820.321094988@linuxfoundation.org>
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[ 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>
---
 net/bluetooth/6lowpan.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 4e2576fc0c59..357475cceec6 100644
--- 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);
 
-- 
2.20.1