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>

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Usefull for all protocols which do not add additional data, such
as GRE or UDPlite.
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>

Commit e1b4b9f3 ([NETFILTER]: {ip,ip6,arp}_tables: fix exponential worst-case
search for loops) introduced a regression in the loop detection algorithm,
causing sporadic incorrectly detected loops.

When a chain has already been visited during the check, it is treated as
having a standard target containing a RETURN verdict directly at the
beginning in order to not check it again. The real target of the first
rule is then incorrectly treated as STANDARD target and checked not to
contain invalid verdicts.

Fix by making sure the rule does actually contain a standard target.

Based on patch by Francis Dupont <Francis_Dupont@isc.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

This is necessary in order to have an upper bound for Netlink
message calculation, which is not a problem at all, as there
are no helpers with a longer name.
Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

It calculates the max. length of a Netlink policy, which is usefull
for allocating Netlink buffers roughly the size of the actual
message.
Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

There is added a single callback for the l3 proto helper.  The two
callbacks for the l4 protos are necessary because of the general
structure of a ctnetlink event, which is in short:

 CTA_TUPLE_ORIG
   <l3/l4-proto-attributes>
 CTA_TUPLE_REPLY
   <l3/l4-proto-attributes>
 CTA_ID
 ...
 CTA_PROTOINFO
   <l4-proto-attributes>
 CTA_TUPLE_MASTER
   <l3/l4-proto-attributes>

Therefore the formular is

 size := sizeof(generic-nlas) + 3 * sizeof(tuple_nlas) + sizeof(protoinfo_nlas)

Some of the NLAs are optional, e. g. CTA_TUPLE_MASTER, which is only
set if it's an expected connection.  But the number of optional NLAs is
small enough to prevent netlink_trim() from reallocating if calculated
properly.
Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

We use same not trivial helper function in four places. We can factorize it.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Using hlist_add_head() in nf_conntrack_set_hashsize() is quite dangerous.
Without any barrier, one CPU could see a loop while doing its lookup.
Its true new table cannot be seen by another cpu, but previous table is still
readable.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

net/netfilter/xt_LED.c:40: error: field netfilter_led_trigger has incomplete type
net/netfilter/xt_LED.c: In function led_timeout_callback:
net/netfilter/xt_LED.c:78: warning: unused variable ledinternal
net/netfilter/xt_LED.c: In function led_tg_check:
net/netfilter/xt_LED.c:102: error: implicit declaration of function led_trigger_register
net/netfilter/xt_LED.c: In function led_tg_destroy:
net/netfilter/xt_LED.c:135: error: implicit declaration of function led_trigger_unregister

Fix by adding a dependency on LED_TRIGGERS.
Reported-by: Sachin Sant <sachinp@in.ibm.com>
Tested-by: Subrata Modak <tosubrata@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

We use RCU to defer freeing of conntrack structures. In DOS situation, RCU might
accumulate about 10.000 elements per CPU in its internal queues. To get accurate
conntrack counts (at the expense of slightly more RAM used), we might consider
conntrack counter not taking into account "about to be freed elements, waiting
in RCU queues". We thus decrement it in nf_conntrack_free(), not in the RCU
callback.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Tested-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
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>

This patchs adds support of modification of the used logger via sysctl.
It can be used to change the logger to module that can not use the bind
operation (ipt_LOG and ipt_ULOG). For this purpose, it creates a
directory /proc/sys/net/netfilter/nf_log which contains a file
per-protocol. The content of the file is the name current logger (NONE if
not set) and a logger can be setup by simply echoing its name to the file.
By echoing "NONE" to a /proc/sys/net/netfilter/nf_log/PROTO file, the
logger corresponding to this PROTO is set to NULL.
Signed-off-by: Eric Leblond <eric@inl.fr>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Introduced by 7ec47496 (netfilter: ctnetlink: cleanup master conntrack assignation):

net/netfilter/nf_conntrack_netlink.c:1275:2: warning: context imbalance in 'ctnetlink_create_conntrack' - different lock contexts for basic block
Signed-off-by: Patrick McHardy <kaber@trash.net>

users have been moved to __nf_ct_l4proto_find.
Signed-off-by: Florian Westphal <fw@strlen.de>
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 adds the iptables cluster match. This match can be used
to deploy gateway and back-end load-sharing clusters. The cluster
can be composed of 32 nodes maximum (although I have only tested
this with two nodes, so I cannot tell what is the real scalability
limit of this solution in terms of cluster nodes).

Assuming that all the nodes see all packets (see below for an
example on how to do that if your switch does not allow this), the
cluster match decides if this node has to handle a packet given:

	(jhash(source IP) % total_nodes) & node_mask

For related connections, the master conntrack is used. The following
is an example of its use to deploy a gateway cluster composed of two
nodes (where this is the node 1):

iptables -I PREROUTING -t mangle -i eth1 -m cluster \
	--cluster-total-nodes 2 --cluster-local-node 1 \
	--cluster-proc-name eth1 -j MARK --set-mark 0xffff
iptables -A PREROUTING -t mangle -i eth1 \
	-m mark ! --mark 0xffff -j DROP
iptables -A PREROUTING -t mangle -i eth2 -m cluster \
	--cluster-total-nodes 2 --cluster-local-node 1 \
	--cluster-proc-name eth2 -j MARK --set-mark 0xffff
iptables -A PREROUTING -t mangle -i eth2 \
	-m mark ! --mark 0xffff -j DROP

And the following commands to make all nodes see the same packets:

ip maddr add 01:00:5e:00:01:01 dev eth1
ip maddr add 01:00:5e:00:01:02 dev eth2
arptables -I OUTPUT -o eth1 --h-length 6 \
	-j mangle --mangle-mac-s 01:00:5e:00:01:01
arptables -I INPUT -i eth1 --h-length 6 \
	--destination-mac 01:00:5e:00:01:01 \
	-j mangle --mangle-mac-d 00:zz:yy:xx:5a:27
arptables -I OUTPUT -o eth2 --h-length 6 \
	-j mangle --mangle-mac-s 01:00:5e:00:01:02
arptables -I INPUT -i eth2 --h-length 6 \
	--destination-mac 01:00:5e:00:01:02 \
	-j mangle --mangle-mac-d 00:zz:yy:xx:5a:27

In the case of TCP connections, pickup facility has to be disabled
to avoid marking TCP ACK packets coming in the reply direction as
valid.

echo 0 > /proc/sys/net/netfilter/nf_conntrack_tcp_loose

BTW, some final notes:

 * This match mangles the skbuff pkt_type in case that it detects
PACKET_MULTICAST for a non-multicast address. This may be done in
a PKTTYPE target for this sole purpose.
 * This match supersedes the CLUSTERIP target.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Module specific data moved into per-net site and being allocated/freed
during net namespace creation/deletion.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Commit 78454473 (netfilter: iptables:
lock free counters) broke a number of modules whose rule data referenced
itself. A reallocation would not reestablish the correct references, so
it is best to use a separate struct that does not fall under RCU.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

The ip_queue module is missing the net-pf-16-proto-3 alias that would
causae it to be auto-loaded when a socket of that type is opened.  This
patch adds the alias.
Signed-off-by: Scott James Remnant <scott@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

The ip6_queue module is missing the net-pf-16-proto-13 alias that would
cause it to be auto-loaded when a socket of that type is opened.  This
patch adds the alias.
Signed-off-by: Scott James Remnant <scott@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
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 increases the statistics of packets drop if the sequence
adjustment fails in ipv4_confirm().
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Signed-off-by: Stephen Hemminger <sheminger@vyatta.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Moving the structure definitions to the corresponding IPvX specific header files.
Signed-off-by: Patrick McHardy <kaber@trash.net>

This patch modifies the proc output to add display of registered
loggers. The content of /proc/net/netfilter/nf_log is modified. Instead
of displaying a protocol per line with format:
	proto:logger
it now displays:
	proto:logger (comma_separated_list_of_loggers)
NONE is used as keyword if no logger is used.
Signed-off-by: Eric Leblond <eric@inl.fr>
Signed-off-by: Patrick McHardy <kaber@trash.net>

This patch modifies nf_log to use a linked list of loggers for each
protocol. This list of loggers is read and write protected with a
mutex.

This patch separates registration and binding. To be used as
logging module, a module has to register calling nf_log_register()
and to bind to a protocol it has to call nf_log_bind_pf().
This patch also converts the logging modules to the new API. For nfnetlink_log,
it simply switchs call to register functions to call to bind function and
adds a call to nf_log_register() during init. For other modules, it just
remove a const flag from the logger structure and replace it with a
__read_mostly.
Signed-off-by: Eric Leblond <eric@inl.fr>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Commit 78454473
(netfilter: iptables: lock free counters) broke xt_hashlimit netfilter module :

This module was storing a pointer inside its xt_hashlimit_info, and this pointer
is not relocated when we temporarly switch tables (iptables -L).

This hack is not not needed at all (probably a leftover from
ancient time), as each cpu should and can access to its own copy.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

iptables imports headers from (the unifdefed headers of a)
kernel tree, but some headers happened to not be installed.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Since tcp_packet() may return -NF_DROP in two situations, the
packet-drop stats must be increased.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

While doing oprofile tests I noticed two loops are not properly unrolled by gcc

Using a hand coded unrolled loop provides nice speedup : ipt_do_table
credited of 2.52 % of cpu instead of 3.29 % in tbench.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Kernel module providing implementation of LED netfilter target.  Each
instance of the target appears as a led-trigger device, which can be
associated with one or more LEDs in /sys/class/leds/
Signed-off-by: Adam Nielsen <a.nielsen@shikadi.net>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

get_random_bytes() is sometimes called with a hard coded size assumption
of an integer. This could not be true for next centuries. This patch
replace it with a compile time statement.
Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Table size is defined as unsigned, wheres the table maximum size is
defined as a signed integer. The calculation of max is 8 or 4,
multiplied the table size. Therefore the max value is aligned to
unsigned.
Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>

The reader/writer lock in ip_tables is acquired in the critical path of
processing packets and is one of the reasons just loading iptables can cause
a 20% performance loss. The rwlock serves two functions:

1) it prevents changes to table state (xt_replace) while table is in use.
   This is now handled by doing rcu on the xt_table. When table is
   replaced, the new table(s) are put in and the old one table(s) are freed
   after RCU period.

2) it provides synchronization when accesing the counter values.
   This is now handled by swapping in new table_info entries for each cpu
   then summing the old values, and putting the result back onto one
   cpu.  On a busy system it may cause sampling to occur at different
   times on each cpu, but no packet/byte counts are lost in the process.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

Sucessfully tested on my dual quad core machine too, but iptables only (no ipv6 here)
BTW, my new "tbench 8" result is 2450 MB/s, (it was 2150 MB/s not so long ago)
Acked-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>