[vserver] Multicast support in vserver

From: <dash700_at_excite.com>
Date: Fri 28 Mar 2008 - 00:06:13 GMT
Message-Id: <20080328000613.3ED8B8B32E@xprdmxin.myway.com>

 Hello VServer experts!

I'm working on a project that uses VServer to provide application isolation functionality. As part of the development we came across a problem supporting multicast binding from inside vserver unless NET_ADMIN capability is turned on. It appears that VServer treats multicast addresses as any other network address. So in order to allow multicast addresses in vserver they need to be a part of NX_INFO list. This list can become quite large if all multicast address space is included.

I've looked at af_inet.c code and it appears that it's easy to provide multicast support if multicast addresses are differentiated from the rest of the address space. I believe this is safe to do because multicast addresses are handled differently by the kernel than normal IP addresses. I've attached a patch against a stable VServer release and 2.6.22 kernel that provides multicast support to vservers without NET_ADMIN capability.

Would it be possible to review this patch for any criticism and possibly inclusion into upcoming stable VServer release if it is useful?

multicast-plain.diff : Kernel patch
demo_mc_bind.c : C program that demonstrates lack of multicast support inside VServer

Thank you in advance!

Sincerely,
Artem Dmytrenko

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Received on Fri Mar 28 20:09:26 2008
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