Hi Alex, On Thu, 2016-06-16 at 23:38 +0200, Alexander Aring wrote: > Hi, > > On 06/16/2016 03:41 PM, Patrik Flykt wrote: > > > > On Thu, 2016-06-16 at 13:00 +0300, Jukka Rissanen wrote: > > > > > > Yes you are right that there are issues. Fortunately the bt0 is > > > currently a point-to-point link in which case ND is not really > > > done > > > and everything kind of "works" ok. > > > > > > I added Patrik to cc: as he has been working to fix the issues > > > but > > > the patches are not yet ready. Perhaps we could combine the > > > efforts > > > here. > > I had some patches that make BTLE interfaces non-point-to-point. > > Let me > > check that they can be applied on the latest bluetooth-next and > > that > > they still compile after a few months of sitting on an old version. > > Then let's hope they also work as expected... > > > With non-point-to-point you mean to remove the IFF_POINTOPOINT flag > in > net_device? Yes this should be removed. Yes, agreed. > > But I think this is one of the smallest issue in btle 6lowpan. > > What means "ND is not really done", does that means you will not see > btle neighbours by doing "ip -6 neigh" for your bt interface? Yes. > > I don't believe that and I think no matter if you set IFF_POINTOPOINT > or > not, the IPv6 stack will mostly ignore such flag. I did a grep and it > seems the SIT stuff sets this flag and IPv6 stack does something with > that, but not in case of ARPHRD_6LOWPAN, it's for ARPHRD_SIT only. So > I > think this flag makes some "peer" address in "ip a" handling instead > of > showing broadcast address. But nobody will make special handling in > IPv6 > or btle 6lowpan if this flag is set. > > What I mean is, you can set this flag on or off but it will don't > change > any behaviour. Unfortunately there is a different behaviour. If the interface has IFF_POINTTOPOINT, then kernel will not send neighbor discovery messages to that link. I have not checked the kernel code where exactly that is enforced but I have looked the wireshark output and there are no ND's sent if bt0 is p-to-p link. If the flag is removed, the device starts to send ND's to that interface. Removing the IFF_POINTTOPPOINT is not enough as the MAC address will be wrongly set in that case as you have noticed. Cheers, Jukka -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
