On Friday, September 4, 2020 8:28:02 PM CEST Linus Lüssing wrote:
For DHCPv6: This is even trickier... DHCPv6 potentially uses non-broadcast multicast addresses. However according to RFC8415, section 7.1 it seems that currently multicast is only used from a DHCPv6 client to a DHCPv6 server, but not the other way round.
Working through the gateway feature part in batadv_interface_tx() it can be inferred that a DHCPv6 packet to a DHCP client would have been the only option for a DHCPv6 multicast packet to be sent via unicast through the gateway feature. Ergo, the newly introduced claim check won't wrongly drop a DHCPv6 packet received via the gateway feature either.
I also don't get this part. Maybe it helps if you can explain the two directions (client -> server, server -> client), and in which cases there can be multicast, and then describe why your check is sufficient?
Fixes: e32470167379 ("batman-adv: check incoming packet type for bla") Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue
net/batman-adv/bridge_loop_avoidance.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c index d8c5d317..9603a6d0 100644 --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -1848,7 +1848,8 @@ bool batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb,
if (unlikely(atomic_read(&bat_priv->bla.num_requests))) /* don't allow broadcasts while requests are in flight */
if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast)
if (is_multicast_ether_addr(ethhdr->h_dest) &&(!is_broadcast_ether_addr(ethhdr->h_dest) || is_bcast)) goto handled;
Isn't this exactly the same logic as it was before?
is_multicast == 0, is_bcast = 0 => 0 is_multicast == 0, is_bcast = 1 => 0 is_multicast == 1, is_bcast = 0 => 0 is_multicast == 1, is_bcast = 1 => 1
ether_addr_copy(search_claim.addr, ethhdr->h_source);@@ -1885,7 +1886,8 @@ bool batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb, }
/* if it is a broadcast ... */
if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast) {
if (is_multicast_ether_addr(ethhdr->h_dest) &&(!is_broadcast_ether_addr(ethhdr->h_dest) || is_bcast)) { /* ... drop it. the responsible gateway is in charge. * * We need to check is_bcast because with the gateway
Same here.