From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4C76EA69.7050301@tiolive.com> Date: Fri, 27 Aug 2010 00:27:53 +0200 From: =?ISO-8859-1?Q?Fran=E7ois_Schmidts?= MIME-Version: 1.0 References: <4C752DD9.7040302@tiolive.com> <4C75724F.2000400@free.fr> <20100825133959.6b409cd8@nehalam> <4C758FD5.4020801@tiolive.com> <4C76C2A4.9070706@free.fr> <4C76D5D7.2040503@free.fr> <20100826144043.3fda9403@nehalam> In-Reply-To: <20100826144043.3fda9403@nehalam> Content-Type: text/plain; charset="iso-8859-1"; format="flowed" Content-Transfer-Encoding: quoted-printable Subject: Re: [Bridge] Number of addresses limitation Reply-To: francois@tiolive.com List-Id: Linux Ethernet Bridging List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stephen Hemminger , bridge@lists.linux-foundation.org On 26/08/2010 23:40, Stephen Hemminger wrote: > On Thu, 26 Aug 2010 23:00:07 +0200 > Nicolas de Peslo=FCan wrote: > >> Le 26/08/2010 21:38, Nicolas de Peslo=FCan a =E9crit : >>> Le 25/08/2010 23:49, Fran=E7ois Schmidts a =E9crit : >>>> On 25/08/2010 22:39, Stephen Hemminger wrote: >>>>> On Wed, 25 Aug 2010 21:43:11 +0200 >>>>> Nicolas de Peslo=FCan wrote: >>>>> >>>>>> Le 25/08/2010 16:51, Fran=E7ois Schmidts a =E9crit : >>>>>>> Hi, >>>>>>> >>>>>>> I'm using bridge-utils to add a bunch of tap interfaces to my compu= ter >>>>>>> so I can run different qemu vm at the same time without using nat to >>>>>>> give them network access. It works fine. >>>>>>> >>>>>>> But at the same time I would like to add a lot of IPv6s addresses t= o the >>>>>>> bridge interface (br0). I find myself limitated to more or less 56 >>>>>>> addresses. If I add one more, one of the addresses already existing= just >>>>>>> disappear from the br0 interface. >>>>>>> >>>>>>> Is there something I could do to remove or extent this limitation ? >>>>>> Did you try the same IPv6 configuration on a normal ethernet NIC ? D= o you think this is a bridge >>>>>> only related problem ? >>>>>> >>>>> Also what tools are you using? Don't use ifconfig (iputils) for IPv6; >>>>> only ip command (iproute2) works correctly with multiple addresses. >>>> I use something like "ip addr add::number/64 dev br0" in a loop >>>> to add quickly multiple addresses to the bridge. >>>> As far as I have tested it on classic interfaces like eth0, it works >>>> fine and I can see my 200 addresses (if I added 200 of them) in the >>>> output of ifconfig. >>> I just tested on a 2.6.32 kernel, and get the following results : >>> >>> Whatever interface I use (bridge or normal Ethernet interface), I'm abl= e to add 200 IPv6 address. >>> >>> "ifconfig" display all the IPv6 address on the interface. >>> "ip addr show" only display about 53 of them. >>> >>> Can you try and ping the 200 IPv6 address from another host, to know wh= ether this is a real IP >>> problem or only a display bug. It might be an iproute2 bug on the addr = show part. >> Another test showed that one can ping the 200 addresses. So this really = look like an iproute2 or >> netlink problem, and unrelated to bridge. >> > I just put 2000 addresses onto dummy device and the all show up > with ip addr. Do you have old tools, the issue is likely the size > of the buffer in netlink interface between ip command and kernel. > Current version has 16K buffer, but it could easily be increased. Thanks for all your answers. I tested all of this all over again and I couldn't recreate the bug,=20 neither on my local machine or on the distant dev server I use for test=20 and where the limitation showed up the first time. I added 2000=20 addresses on both which were reachable to ping without difficulties. The problem may have come from a display bug from the tool I used then=20 to list IP addresses. Sorry to have bothered you with an "nonexistent" bug and thanks again.