On 2/15/17 8:08 PM, Eric W. Biederman wrote: > David Ahern <d...@cumulusnetworks.com> writes: > >> On 2/14/17 12:21 AM, Eric W. Biederman wrote: >>>> in cases where bpf programs are looking at sockets and packets >>>> that belong to different netns, it could be useful to get an id >>>> that uniquely identify a netns within the whole system. >>> It could be useful but there is no unique namespace id. >>> >> >> Have you given thought to a unique namespace id? Networking tracepoints >> for example could really benefit from a unique id. > > An id from the perspective of a process in the initial instance of every > namespace is certainly possible. > > A truly unique id is just not maintainable. Think of the question how > do you assign every device in the world a rguaranteed unique ip address > without coordination, that is routable. It is essentially the same > problem. > > AKA it is theoretically possible and very expensive. It is much easier > and much more maintainable for identifiers to have scope and only be > unique within that scope.
I don't mean unique in the entire world, I mean unique within a single system. Tracepoints are code based and have global scope. I would like to be able to correlate, for example, FIB lookups within a single network namespace. Having an id that I could filter on when collecting or match when dumping them goes a long way.
