Hi, On 14/02/2019 16:52, Linus Lüssing wrote: > Currently incoming ARP Replies, for example via a DHT-PUT message, do > not update the timeout for an already existing DAT entry. These ARP > Replies are dropped instead. > > This however defeats the purpose of the DHCPACK snooping, for instance. > Right now, a DAT entry in the DHT will be purged every five minutes, > likely leading to a mesh-wide ARP Request broadcast after this timeout. > Which then recreates the entry. The idea of the DHCPACK snooping is to > be able to update an entry before a timeout happens, to avoid ARP Request > flooding. > > This patch fixes this issue by updating a DAT entry on incoming > ARP Replies even if a matching DAT entry already exists. While still > filtering the ARP Reply towards the soft-interface, to avoid duplicate > messages on the client device side. > > Signed-off-by: Linus Lüssing <linus.luess...@c0d3.blue> > --- > > This patch was verified in VMs via gratuitous ARP Replies generated by > "mausezahn", together with the > "batman-adv: allow snooping gratuitous ARP Replies" patch. > > Before this patch, the timeout observed via "batctl dc" would continue > to increase on gratuitous ARP Reply reception. After this patch, the > last-seen value was reset to 0 successfully. > --- > net/batman-adv/distributed-arp-table.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/net/batman-adv/distributed-arp-table.c > b/net/batman-adv/distributed-arp-table.c > index 310a4f35..8d290da0 100644 > --- a/net/batman-adv/distributed-arp-table.c > +++ b/net/batman-adv/distributed-arp-table.c > @@ -1444,7 +1444,6 @@ bool batadv_dat_snoop_incoming_arp_reply(struct > batadv_priv *bat_priv, > hw_src, &ip_src, hw_dst, &ip_dst, > dat_entry->mac_addr, &dat_entry->ip); > dropped = true; > - goto out; > } > > /* Update our internal cache with both the IP addresses the node got > @@ -1453,6 +1452,9 @@ bool batadv_dat_snoop_incoming_arp_reply(struct > batadv_priv *bat_priv, > batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid); > batadv_dat_entry_add(bat_priv, ip_dst, hw_dst, vid); > > + if (dropped) > + goto out; > + > /* If BLA is enabled, only forward ARP replies if we have claimed the > * source of the ARP reply or if no one else of the same backbone has > * already claimed that client. This prevents that different gateways >
The patch makes sense, especially because this change will allow to "refresh" entries before they expire (No matter how the ARP reply was generated) Acked-by: Antonio Quartulli <a...@unstable.cc> -- Antonio Quartulli
signature.asc
Description: OpenPGP digital signature
