linux-toradex.git/include/net/netns, branch v2.6.32.9

netfilter: nf_conntrack: fix hash resizing with namespaces

2010-02-23T15:37:53+00:00

commit d696c7bdaa55e2208e56c6f98e6bc1599f34286d upstream.

As noticed by Jon Masters , the conntrack hash
size is global and not per namespace, but modifiable at runtime through
/sys/module/nf_conntrack/hashsize. Changing the hash size will only
resize the hash in the current namespace however, so other namespaces
will use an invalid hash size. This can cause crashes when enlarging
the hashsize, or false negative lookups when shrinking it.

Move the hash size into the per-namespace data and only use the global
hash size to initialize the per-namespace value when instanciating a
new namespace. Additionally restrict hash resizing to init_net for
now as other namespaces are not handled currently.

Signed-off-by: Patrick McHardy 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_conntrack: per netns nf_conntrack_cachep

2010-02-23T15:37:53+00:00

commit 5b3501faa8741d50617ce4191c20061c6ef36cb3 upstream.

nf_conntrack_cachep is currently shared by all netns instances, but
because of SLAB_DESTROY_BY_RCU special semantics, this is wrong.

If we use a shared slab cache, one object can instantly flight between
one hash table (netns ONE) to another one (netns TWO), and concurrent
reader (doing a lookup in netns ONE, 'finding' an object of netns TWO)
can be fooled without notice, because no RCU grace period has to be
observed between object freeing and its reuse.

We dont have this problem with UDP/TCP slab caches because TCP/UDP
hashtables are global to the machine (and each object has a pointer to
its netns).

If we use per netns conntrack hash tables, we also *must* use per netns
conntrack slab caches, to guarantee an object can not escape from one
namespace to another one.

Signed-off-by: Eric Dumazet 
[Patrick: added unique slab name allocation]
Signed-off-by: Patrick McHardy 
Signed-off-by: Greg Kroah-Hartman

netns: embed ip6_dst_ops directly

2009-09-02T00:40:31+00:00

struct net::ipv6.ip6_dst_ops is separatedly dynamically allocated,
but there is no fundamental reason for it. Embed it directly into
struct netns_ipv6.

For that:
* move struct dst_ops into separate header to fix circular dependencies
	I honestly tried not to, it's pretty impossible to do other way
* drop dynamical allocation, allocate together with netns

For a change, remove struct dst_ops::dst_net, it's deducible
by using container_of() given dst_ops pointer.

Signed-off-by: Alexey Dobriyan 
Signed-off-by: David S. Miller

net, netns_xt: shrink netns_xt members

2009-07-06T02:16:18+00:00

In case if kernel was compiled without ebtables support
there is no need to keep ebt_table pointers in netns_xt
structure.

Make it config dependent.

Signed-off-by: Cyrill Gorcunov 
Signed-off-by: David S. Miller

netfilter: conntrack: optional reliable conntrack event delivery

2009-06-13T10:30:52+00:00

This patch improves ctnetlink event reliability if one broadcast
listener has set the NETLINK_BROADCAST_ERROR socket option.

The logic is the following: if an event delivery fails, we keep
the undelivered events in the missed event cache. Once the next
packet arrives, we add the new events (if any) to the missed
events in the cache and we try a new delivery, and so on. Thus,
if ctnetlink fails to deliver an event, we try to deliver them
once we see a new packet. Therefore, we may lose state
transitions but the userspace process gets in sync at some point.

At worst case, if no events were delivered to userspace, we make
sure that destroy events are successfully delivered. Basically,
if ctnetlink fails to deliver the destroy event, we remove the
conntrack entry from the hashes and we insert them in the dying
list, which contains inactive entries. Then, the conntrack timer
is added with an extra grace timeout of random32() % 15 seconds
to trigger the event again (this grace timeout is tunable via
/proc). The use of a limited random timeout value allows
distributing the "destroy" resends, thus, avoiding accumulating
lots "destroy" events at the same time. Event delivery may
re-order but we can identify them by means of the tuple plus
the conntrack ID.

The maximum number of conntrack entries (active or inactive) is
still handled by nf_conntrack_max. Thus, we may start dropping
packets at some point if we accumulate a lot of inactive conntrack
entries that did not successfully report the destroy event to
userspace.

During my stress tests consisting of setting a very small buffer
of 2048 bytes for conntrackd and the NETLINK_BROADCAST_ERROR socket
flag, and generating lots of very small connections, I noticed
very few destroy entries on the fly waiting to be resend.

A simple way to test this patch consist of creating a lot of
entries, set a very small Netlink buffer in conntrackd (+ a patch
which is not in the git tree to set the BROADCAST_ERROR flag)
and invoke `conntrack -F'.

For expectations, no changes are introduced in this patch.
Currently, event delivery is only done for new expectations (no
events from expectation expiration, removal and confirmation).
In that case, they need a per-expectation event cache to implement
the same idea that is exposed in this patch.

This patch can be useful to provide reliable flow-accouting. We
still have to add a new conntrack extension to store the creation
and destroy time.

Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Patrick McHardy

netfilter: conntrack: move event caching to conntrack extension infrastructure

2009-06-13T10:26:29+00:00

This patch reworks the per-cpu event caching to use the conntrack
extension infrastructure.

The main drawback is that we consume more memory per conntrack
if event delivery is enabled. This patch is required by the
reliable event delivery that follows to this patch.

BTW, this patch allows you to enable/disable event delivery via
/proc/sys/net/netfilter/nf_conntrack_events in runtime, although
you can still disable event caching as compilation option.

Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Patrick McHardy

netfilter: nf_conntrack: use SLAB_DESTROY_BY_RCU and get rid of call_rcu()

2009-03-25T20:05:46+00:00

Use "hlist_nulls" infrastructure we added in 2.6.29 for RCUification of UDP & TCP.

This permits an easy conversion from call_rcu() based hash lists to a
SLAB_DESTROY_BY_RCU one.

Avoiding call_rcu() delay at nf_conn freeing time has numerous gains.

First, it doesnt fill RCU queues (up to 10000 elements per cpu).
This reduces OOM possibility, if queued elements are not taken into account
This reduces latency problems when RCU queue size hits hilimit and triggers
emergency mode.

- It allows fast reuse of just freed elements, permitting better use of
CPU cache.

- We delete rcu_head from "struct nf_conn", shrinking size of this structure
by 8 or 16 bytes.

This patch only takes care of "struct nf_conn".
call_rcu() is still used for less critical conntrack parts, that may
be converted later if necessary.

Signed-off-by: Eric Dumazet 
Signed-off-by: Patrick McHardy

netns: ipmr: declare reg_vif_num per-namespace

2009-01-22T21:57:40+00:00

Preliminary work to make IPv4 multicast routing netns-aware.

Declare variable 'reg_vif_num' per-namespace, move into struct netns_ipv4.

At the moment, this variable is only referenced in init_net.

Signed-off-by: Benjamin Thery 
Signed-off-by: David S. Miller

netns: ipmr: declare mroute_do_assert and mroute_do_pim per-namespace

2009-01-22T21:57:40+00:00

Preliminary work to make IPv4 multicast routing netns-aware.

Declare IPv multicast routing variables 'mroute_do_assert' and
'mroute_do_pim' per-namespace in struct netns_ipv4.

At the moment, these variables are only referenced in init_net.

Signed-off-by: Benjamin Thery 
Signed-off-by: David S. Miller

netns: ipmr: declare counter cache_resolve_queue_len per-namespace

2009-01-22T21:57:39+00:00

Preliminary work to make IPv4 multicast routing netns-aware.

Declare variable cache_resolve_queue_len per-namespace: move it into
struct netns_ipv4.

This variable counts the number of unresolved cache entries queued in the
list mfc_unres_queue. This list is kept global to all netns as the number
of entries per namespace is limited to 10 (hardcoded in routine
ipmr_cache_unresolved).
Entries belonging to different namespaces in mfc_unres_queue will be
identified by matching the mfc_net member introduced previously in
struct mfc_cache.

Keeping this list global to all netns, also allows us to keep a single
timer (ipmr_expire_timer) to handle their expiration.
In some places cache_resolve_queue_len value was tested for arming
or deleting the timer. These tests were equivalent to testing
mfc_unres_queue value instead and are replaced in this patch.

At the moment, cache_resolve_queue_len is only referenced in init_net.

Signed-off-by: Benjamin Thery 
Signed-off-by: David S. Miller