From: Linus Lüssing linus.luessing@c0d3.blue
[ Upstream commit 7dda5b3384121181c4e79f6eaeac2b94c0622c8d ]
The unicast packet rerouting code makes several assumptions. For instance it assumes that there is always exactly one destination in the TT. This breaks for multicast frames in a unicast packets in several ways:
For one thing if there is actually no TT entry and the destination node was selected due to the multicast tvlv flags it announced. Then an intermediate node will wrongly drop the packet.
For another thing if there is a TT entry but the TTVN of this entry is newer than the originally addressed destination node: Then the intermediate node will wrongly redirect the packet, leading to duplicated multicast packets at a multicast listener and missing packets at other multicast listeners or multicast routers.
Fixing this by not applying the unicast packet rerouting to batman-adv unicast packets with a multicast payload. We are not able to detect a roaming multicast listener at the moment and will just continue to send the multicast frame to both the new and old destination for a while in case of such a roaming multicast listener.
Fixes: a73105b8d4c7 ("batman-adv: improved client announcement mechanism") Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/batman-adv/routing.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c index cc3ed93a6d51..98af41e3810d 100644 --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -838,6 +838,10 @@ static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv, vid = batadv_get_vid(skb, hdr_len); ethhdr = (struct ethhdr *)(skb->data + hdr_len);
+ /* do not reroute multicast frames in a unicast header */ + if (is_multicast_ether_addr(ethhdr->h_dest)) + return true; + /* check if the destination client was served by this node and it is now * roaming. In this case, it means that the node has got a ROAM_ADV * message and that it knows the new destination in the mesh to re-route