@@ -412,11 +414,28 @@ void batadv_interface_rx(struct net_device *soft_iface, ethhdr = eth_hdr(skb);
switch (ntohs(ethhdr->h_proto)) {
case ETH_P_IP:iphdr = (struct iphdr *)(skb->data + ETH_HLEN);/* snoop incoming traffic for dat update using the
source
mac
* and source ip to speed up dat.* Question: does this break the fundamental idea ofdat????
*/That is a really good question, although it doesn't belong in the code
;)
I know, but I was myself unsure if this is a good idea and wanted to provoke a discussion about this ;-)
@Antonio, CC'ing you since this is more a design question/proposal and you may have thought about this yet.
Basically, doing this change means that we will put a lot of IP
addresses in
our cache which are not in our local network - typically, all Internet
IP
addresses along with the gateway backbone. Also these addresses
willnever be
requested by ARP and are therefore practically just littering our cache.
They
are purged after 5 minutes so the impact may be reasonable, but still
...
I agree that performance and especially consumption of RAM is an issue here depending on the network size....
Maybe there is a way to limit the entries to local networks? Also (and
in
general), should we have an upper limit how many entries we store in
DAT?
After applying this patch, doing a subnet ping scan can deplete the RAM
in
small routers I'm afraid. :)
(even now, that would be possible with fake ARP replies I guess)
Also, why don't you check the ip destination as well while at it?
I only tried to check the source addresses with the gateways of a bla setup in mind. The goal was to increase the possiblity that already the gateway can answer the arp request. In this case only the traffic traveling from mesh to backbone is relevant. One could also snoop destination addresse for traffic from backbone to mesh, but do you think that this adds an extra benefit of addtional information except risking another decrease in forwarding performance ?
Cheers, Simon
Kind regards, Andreas
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