Denis V. Lunev wrote:
Daniel Lezcano wrote:
Denis V. Lunev wrote:
Daniel Lezcano wrote:
Denis V. Lunev wrote:
/proc/sys/net/route/flush should be accessible inside the net
namespace.
Though, the complete opening of this file will result in a DoS or
significant entire host slowdown if a namespace process will
continually
flush routes.
This patch introduces per/namespace route flush facility.
Each namespace wanted to flush a cache copies global generation
count to
itself and starts the timer. The cache is dropped for a specific
namespace
iff the namespace counter is greater or equal global ones.
So, in general, unwanted namespaces do nothing. They hold very old low
counter and they are unaffected by the requested cleanup.
Signed-of-by: Denis V. Lunev <den@xxxxxxxxxx>
That's right and that will happen when manipulating ip addresses of
the network devices too. But I am not confortable with your
patchset. It touches the routing flush function too hardly and it
uses current->nsproxy->net_ns.
IMHO we should have two flush functions. One taking a network
namespace parameter and one without the network namespace parameter.
The first one is called when a write to
/proc/sys/net/ipv4/route/flush is done (we must use the network
namespace of the writer) or when a interface address is changed or
shutdown|up. The last one is called by the timer, so we have a
global timer flushing the routing cache for all the namespaces.
we can't :( The unfortunate thing is that the actual cleanup is
called indirectly and asynchronously. The user _schedule_ the garbage
collector to run NOW and we are moving over a large routing cache.
Really large.
The idea to iterate over the list of each namespace to flush is bad.
We are in atomic context. The list is protected by the mutex.
Oh, by the way, I forgot something important you spotted with the list
protected by the mutex.
When looking at ipv6/fib_hash.c with Benjamin, we need to browse the
network namespaces list for the garbage collecting, but we are in an
interrupt handler, so I can not use rtnl_lock.
Why is not possible to protect the list with a simple spinlock ? so we
can call spin_lock_bh when we are in interrupt handler.
_______________________________________________
Containers mailing list
Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/containers
