This patch fixes a bug that allows to lose events when reliable
event delivery mode is used, ie. if NETLINK_BROADCAST_SEND_ERROR
and NETLINK_RECV_NO_ENOBUFS socket options are set.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes a bug that triggers an assertion if you create
a conntrack entry with a helper and netfilter debugging is enabled.
Basically, we hit the assertion because the confirmation flag is
set before the conntrack extensions are added. To fix this, we
move the extension addition before the aforementioned flag is
set.
This patch also removes the possibility of setting a helper for
existing conntracks. This operation would also trigger the
assertion since we are not allowed to add new extensions for
existing conntracks. We know noone that could benefit from
this operation sanely.
Thanks to Eric Dumazet for initial posting a preliminary patch
to address this issue.
Reported-by: David Ramblewski <David.Ramblewski@atosorigin.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Normally, each connection needs a unique identity. Conntrack zones allow
to specify a numerical zone using the CT target, connections in different
zones can use the same identity.
Example:
iptables -t raw -A PREROUTING -i veth0 -j CT --zone 1
iptables -t raw -A OUTPUT -o veth1 -j CT --zone 1
Signed-off-by: Patrick McHardy <kaber@trash.net>
As noticed by Jon Masters <jonathan@jonmasters.org>, 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.
Cc: stable@kernel.org
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Support initializing selected parameters of new conntrack entries from a
"conntrack template", which is a specially marked conntrack entry attached
to the skb.
Currently the helper and the event delivery masks can be initialized this
way.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Add two masks for conntrack end expectation events to struct nf_conntrack_ecache
and use them to filter events. Their default value is "all events" when the
event sysctl is on and "no events" when it is off. A following patch will add
specific initializations. Expectation events depend on the ecache struct of
their master conntrack.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Split up the IPCT_STATUS event into an IPCT_REPLY event, which is generated
when the IPS_SEEN_REPLY bit is set, and an IPCT_ASSURED event, which is
generated when the IPS_ASSURED bit is set.
In combination with a following patch to support selective event delivery,
this can be used for "sparse" conntrack replication: start replicating the
conntrack entry after it reached the ASSURED state and that way it's SYN-flood
resistant.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Make sure not to assign a helper for a different network or transport
layer protocol to a connection.
Additionally change expectation deletion by helper to compare the name
directly - there might be multiple helper registrations using the same
name, currently one of them is chosen in an unpredictable manner and
only those expectations are removed.
Signed-off-by: Patrick McHardy <kaber@trash.net>
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 <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
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 <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Introduce per-conntrack locks and use them instead of the global protocol
locks to avoid contention. Especially tcp_lock shows up very high in
profiles on larger machines.
This will also allow to simplify the upcoming reliable event delivery patches.
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch removes the notify chain infrastructure and replace it
by a simple function pointer. This issue has been mentioned in the
mailing list several times: the use of the notify chain adds
too much overhead for something that is only used by ctnetlink.
This patch also changes nfnetlink_send(). It seems that gfp_any()
returns GFP_KERNEL for user-context request, like those via
ctnetlink, inside the RCU read-side section which is not valid.
Using GFP_KERNEL is also evil since netlink may schedule(),
this leads to "scheduling while atomic" bug reports.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch simplifies the conntrack event caching system by removing
several events:
* IPCT_[*]_VOLATILE, IPCT_HELPINFO and IPCT_NATINFO has been deleted
since the have no clients.
* IPCT_COUNTER_FILLING which is a leftover of the 32-bits counter
days.
* IPCT_REFRESH which is not of any use since we always include the
timeout in the messages.
After this patch, the existing events are:
* IPCT_NEW, IPCT_RELATED and IPCT_DESTROY, that are used to identify
addition and deletion of entries.
* IPCT_STATUS, that notes that the status bits have changes,
eg. IPS_SEEN_REPLY and IPS_ASSURED.
* IPCT_PROTOINFO, that reports that internal protocol information has
changed, eg. the TCP, DCCP and SCTP protocol state.
* IPCT_HELPER, that a helper has been assigned or unassigned to this
entry.
* IPCT_MARK and IPCT_SECMARK, that reports that the mark has changed, this
covers the case when a mark is set to zero.
* IPCT_NATSEQADJ, to report that there's updates in the NAT sequence
adjustment.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
During the module removal there are no possible event listeners
since ctnetlink must be removed before to allow removing
nf_conntrack. This patch removes the event reporting for the
module removal case which is not of any use in the existing code.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch cleans up the message calculation to make it similar
to rtnetlink, moreover, it removes unneeded verbose information.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch is a cleanup, it removes the `nowait' parameter
from all *fill_info() function since it is always set to one.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch fixes the wrong message type that are triggered by
user updates, the following commands:
(term1)# conntrack -I -p tcp -s 1.1.1.1 -d 2.2.2.2 -t 10 --sport 10 --dport 20 --state LISTEN
(term1)# conntrack -U -p tcp -s 1.1.1.1 -d 2.2.2.2 -t 10 --sport 10 --dport 20 --state SYN_SENT
(term1)# conntrack -U -p tcp -s 1.1.1.1 -d 2.2.2.2 -t 10 --sport 10 --dport 20 --state SYN_RECV
only trigger event message of type NEW, when only the first is NEW
while others should be UPDATE.
(term2)# conntrack -E
[NEW] tcp 6 10 LISTEN src=1.1.1.1 dst=2.2.2.2 sport=10 dport=20 [UNREPLIED] src=2.2.2.2 dst=1.1.1.1 sport=20 dport=10 mark=0
[NEW] tcp 6 10 SYN_SENT src=1.1.1.1 dst=2.2.2.2 sport=10 dport=20 [UNREPLIED] src=2.2.2.2 dst=1.1.1.1 sport=20 dport=10 mark=0
[NEW] tcp 6 10 SYN_RECV src=1.1.1.1 dst=2.2.2.2 sport=10 dport=20 [UNREPLIED] src=2.2.2.2 dst=1.1.1.1 sport=20 dport=10 mark=0
This patch also removes IPCT_REFRESH from the bitmask since it is
not of any use.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch fixes a (bogus?) gcc warning during compilation:
net/netfilter/nf_conntrack_netlink.c🔢 warning: 'helpname' may be used uninitialized in this function
net/netfilter/nf_conntrack_netlink.c:991: warning: 'helpname' may be used uninitialized in this function
In fact, helpname is initialized by ctnetlink_parse_help() so
I cannot see a way to use it without being initialized.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes an inconsistency that results in no error reports
to user-space listeners if we fail to allocate the event message.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
On a box with most of the optional Netfilter switches turned off some
of the NLAs are never send, e. g. secmark, mark or the conntrack
byte/packet counters. As a worst case scenario this may possibly
still lead to ctnetlink skbs being reallocated in netlink_trim()
later, loosing all the nice effects from the previous patches.
I try to solve that (at least partly) by correctly #ifdef'ing the
NLAs in the computation.
Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Try to allocate a Netlink skb roughly the size of the actual
message, with the help from the l3 and l4 protocol helpers.
This is all to prevent a reallocation in netlink_trim() later.
The overhead of allocating the right-sized skb is rather small, with
ctnetlink_alloc_skb() actually being inlined away on my x86_64 box.
The size of the per-proto space is determined at registration time of
the protocol helper.
Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
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 <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch adds nfnetlink_set_err() to propagate the error to netlink
broadcast listener in case of memory allocation errors in the
message building.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Convert the remaining refcount users.
As pointed out by Patrick McHardy, the protocols can be accessed safely using RCU.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch fixes a possible crash due to the missing initialization
of the expectation class when nf_ct_expect_related() is called.
Reported-by: BORBELY Zoltan <bozo@andrews.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch moves the event reporting outside the lock section. With
this patch, the creation and update of entries is homogeneous from
the event reporting perspective. Moreover, as the event reporting is
done outside the lock section, the netlink broadcast delivery can
benefit of the yield() call under congestion.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch moves the preliminary checkings that must be fulfilled
to update a conntrack, which are the following:
* NAT manglings cannot be updated
* Changing the master conntrack is not allowed.
This patch is a cleanup.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch moves the assignation of the master conntrack to
ctnetlink_create_conntrack(), which is where it really belongs.
This patch is a cleanup.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This patch fixes echoing if the socket that has sent the request to
create/update/delete an entry is not subscribed to any multicast
group. With the current code, ctnetlink would not send the echo
message via unicast as nfnetlink_send() would be skip.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes an inconsistency in the current ctnetlink code
since NAT sequence adjustment bit can only be updated but not set
in the conntrack entry creation.
This patch is used by conntrackd to successfully recover newly
created entries that represent connections with helpers and NAT
payload mangling.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Caused by call to request_module() while holding nf_conntrack_lock.
Reported-and-tested-by: Kövesdi György <kgy@teledigit.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
nf_conntrack_alloc cannot return NULL, so there is no need to check for
NULL before using the value. I have also removed the initialization of ct
to NULL in nf_conntrack_alloc, since the value is never used, and since
perhaps it might lead one to think that return ct at the end might return
NULL.
The semantic patch that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@match exists@
expression x, E;
position p1,p2;
statement S1, S2;
@@
x@p1 = nf_conntrack_alloc(...)
... when != x = E
(
if (x@p2 == NULL || ...) S1 else S2
|
if (x@p2 == NULL && ...) S1 else S2
)
@other_match exists@
expression match.x, E1, E2;
position p1!=match.p1,match.p2;
@@
x@p1 = E1
... when != x = E2
x@p2
@ script:python depends on !other_match@
p1 << match.p1;
p2 << match.p2;
@@
print "%s: call to nf_conntrack_alloc %s bad test %s" % (p1[0].file,p1[0].line,p2[0].line)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The previous fix for the conntrack creation race (netfilter: ctnetlink:
fix conntrack creation race) missed a GFP_KERNEL allocation that is
now performed while holding a spinlock. Switch to GFP_ATOMIC.
Reported-and-tested-by: Zoltan Borbely <bozo@andrews.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conntrack creation through ctnetlink has two races:
- the timer may expire and free the conntrack concurrently, causing an
invalid memory access when attempting to put it in the hash tables
- an identical conntrack entry may be created in the packet processing
path in the time between the lookup and hash insertion
Hold the conntrack lock between the lookup and insertion to avoid this.
Reported-by: Zoltan Borbely <bozo@andrews.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
As for now, the creation and update of conntracks via ctnetlink do not
propagate an event to userspace. This can result in inconsistent situations
if several userspace processes modify the connection tracking table by means
of ctnetlink at the same time. Specifically, using the conntrack command
line tool and conntrackd at the same time can trigger unconsistencies.
This patch also modifies the event cache infrastructure to pass the
process PID and the ECHO flag to nfnetlink_send() to report back
to userspace if the process that triggered the change needs so.
Based on a suggestion from Patrick McHardy.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Pablo Neira Ayuso