Date: Thu, 18 Oct 2012 09:36:00 -0700 From: Maksim Yevmenkin <maksim.yevmenkin@gmail.com> To: Andreas Longwitz <longwitz@incore.de> Cc: freebsd-bluetooth@freebsd.org Subject: Re: btpand problem Message-ID: <CAFPOs6oDHjqCLbeWwMx0kguCw1w_VD0bEwxkhodZwnJnQ0AY_Q@mail.gmail.com> In-Reply-To: <507C7D76.4090303@incore.de> References: <507736A8.4050605@incore.de> <BDA3CA14-92C0-414E-9D55-E96EA7A73312@gmail.com> <5077490F.7010901@incore.de> <CAFPOs6pF51wy9PvKLn4-OnrOqo8hU1S=P5PzTFwgUppBjqAtuA@mail.gmail.com> <alpine.NEB.2.00.1210120949170.628@galant.ukfsn.org> <50782E05.5080005@incore.de> <alpine.NEB.2.00.1210122254010.965@galant.ukfsn.org> <CAFPOs6qWVAcSuPz6%2BB=3uq_KqCXa=YcXwx-PNncGVrbDE8AimQ@mail.gmail.com> <5079E8F7.5050903@incore.de> <alpine.NEB.2.00.1210140843330.548@galant.ukfsn.org> <alpine.NEB.2.00.1210140917360.673@galant.ukfsn.org> <507B0C57.7030506@incore.de> <alpine.NEB.2.00.1210150936490.753@galant.ukfsn.org> <507C7D76.4090303@incore.de>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, Oct 15, 2012 at 2:17 PM, Andreas Longwitz <longwitz@incore.de> wrote: > Hi, > >> as I said, I think 672 is a bit low, though I used 4096 for NetBSD (with a >> sysctl for runtime adjustment if necessary) and that is still potentially >> prone to error with larger packets (L2CAP MTU between 48-65535 bytes is >> valid) so I guess that requiring the application to set the buffer size is >> best practice.. > > I agree. > >>> Now I describe another problem with my ping test, I am not sure if this >>> problem concerns btpand too. If the ICMP packet must be fragmented, then the >>> first fragment ist lost on the tap interface (and can not be found by tcpdump >>> running on this tap) if an ARP request is necessary. >>> ping -c 1 -s 1400 panserver >>> works all the time, >>> ping -c 1 -s 1600 panserver >>> only works if the ip address of panserver is in the arp cache. >> >> does the ARP request get sent out? > > Yes and the arp answer comes in. > >>> I did nothing special with the tap interface, it is included in my >>> "cloned_interfaces" in rc.conf and opened by btpand. >>> >>> Any ideas ? >> >> No, I confess. > > My problem was a phantom ! It seems to be normal behavior in any network > and has nothing to do with btpand or tap interface. This was a little > bit suprising to me but I have checked this on several networks. An > explanation for this was given on freebsd-net some years ago titled > Lost fragment when send to ip that need arp resolve. > > Thanks again for help! just in case Author: emax Date: Thu Oct 18 16:34:00 2012 New Revision: 241699 URL: http://svn.freebsd.org/changeset/base/241699 Log: make sure that socket's send and receive buffers are properly sized Submitted by: Iain Hibbert plunky at rya-online dot net MFC after: 3 weeks Modified: head/usr.sbin/bluetooth/btpand/client.c head/usr.sbin/bluetooth/btpand/server.c thanks max
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAFPOs6oDHjqCLbeWwMx0kguCw1w_VD0bEwxkhodZwnJnQ0AY_Q>