This patch adds support for set flushing, that consists of walking over
the set elements if the NFTA_SET_ELEM_LIST_ELEMENTS attribute is set.
This patch requires the following changes:

1) Add set->ops->deactivate_one() operation: This allows us to
   deactivate an element from the set element walk path, given we can
   skip the lookup that happens in ->deactivate().

2) Add a new nft_trans_alloc_gfp() function since we need to allocate
   transactions using GFP_ATOMIC given the set walk path happens with
   held rcu_read_lock.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This new function allows us to deactivate one single element, this is
required by the set flush command that comes in a follow up patch.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Context is not modified by nft_trans_alloc(), so constify it.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

SCTP GSO and hardware can do CRC32c computation after netfilter processing,
so we can avoid calling sctp_compute_checksum() on skb if skb->ip_summed
is equal to CHECKSUM_PARTIAL. Moreover, set skb->ip_summed to CHECKSUM_NONE
when the NAT code computes the CRC, to prevent offloaders from computing
it again (on ixgbe this resulted in a transmission with wrong L4 checksum).
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Otherwise, DHCP Discover packets(0.0.0.0->255.255.255.255) may be
dropped incorrectly.
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This patch adds the netlink code to filter out dump of stateful objects,
through the NFTA_OBJ_TYPE netlink attribute.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This patch allows us to refer to stateful object dictionaries, the
source register indicates the key data to be used to look up for the
corresponding state object. We can refer to these maps through names or,
alternatively, the map transaction id. This allows us to refer to both
anonymous and named maps.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This patch allows you to refer to stateful objects from set elements.
This provides the infrastructure to create maps where the right hand
side of the mapping is a stateful object.

This allows us to build dictionaries of stateful objects, that you can
use to perform fast lookups using any arbitrary key combination.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Notify on depleted quota objects. The NFT_QUOTA_F_DEPLETED flag
indicates we have reached overquota.

Add pointer to table from nft_object, so we can use it when sending the
depletion notification to userspace.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Introduce nf_tables_obj_notify() to notify internal state changes in
stateful objects. This is used by the quota object to report depletion
in a follow up patch.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This patch adds a new NFT_MSG_GETOBJ_RESET command perform an atomic
dump-and-reset of the stateful object. This also comes with add support
for atomic dump and reset for counter and quota objects.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Add a new attribute NFTA_QUOTA_CONSUMED that displays the amount of
quota that has been already consumed. This allows us to restore the
internal state of the quota object between reboots as well as to monitor
how wasted it is.

This patch changes the logic to account for the consumed bytes, instead
of the bytes that remain to be consumed.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This new expression allows us to refer to existing stateful objects from
rules.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Register a new quota stateful object type into the new stateful object
infrastructure.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Register a new percpu counter stateful object type into the stateful
object infrastructure.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This patch augments nf_tables to support stateful objects. This new
infrastructure allows you to create, dump and delete stateful objects,
that are identified by a user-defined name.

This patch adds the generic infrastructure, follow up patches add
support for two stateful objects: counters and quotas.

This patch provides a native infrastructure for nf_tables to replace
nfacct, the extended accounting infrastructure for iptables.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

... so we can use current skb instead of working with a clone.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

The caller assumes that < 0 means that skb was stolen (or free'd).

All other return values continue skb processing.

nf_hook_slow returns 3 different return value types:

A) a (negative) errno value: the skb was dropped (NF_DROP, e.g.
by iptables '-j DROP' rule).

B) 0. The skb was stolen by the hook or queued to userspace.

C) 1. all hooks returned NF_ACCEPT so the caller should invoke
   the okfn so packet processing can continue.

nft ingress facility currently doesn't have the 'okfn' that
the NF_HOOK() macros use; there is no nfqueue support either.

So 1 means that nf_hook_ingress() caller should go on processing the skb.

In order to allow use of NF_STOLEN from ingress we need to translate
this to an errno number, else we'd crash because we continue with
already-free'd (or about to be free-d) skb.

The errno value isn't checked, its just important that its less than 0,
so return -1.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

I lost one test case in the last commit for xt_multiport.
For example, the rule is "-m multiport --dports 22,80,443".
When first port is unmatched and the second is matched, the curent codes
could not return the right result.
It would return false directly when the first port is unmatched.

Fixes: dd2602d0 ("netfilter: xt_multiport: Use switch case instead
of multiple condition checks")
Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This patch adds a new flag that signals the kernel to update layer 4
checksum if the packet field belongs to the layer 4 pseudoheader. This
implicitly provides stateless NAT 1:1 that is useful under very specific
usecases.

Since rules mangling layer 3 fields that are part of the pseudoheader
may potentially convey any layer 4 packet, we have to deal with the
layer 4 checksum adjustment using protocol specific code.

This patch adds support for TCP, UDP and ICMPv6, since they include the
pseudoheader in the layer 4 checksum calculation. ICMP doesn't, so we
can skip it.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Otherwise, if fib lookup fail, *dest will be filled with garbage value,
so reverse path filtering will not work properly:
 # nft add rule x prerouting fib saddr oif eq 0 drop

Fixes: f6d0cbcf ("netfilter: nf_tables: add fib expression")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Acctually ntohl and htonl are identical, so this doesn't affect
anything, but it is conceptually wrong.
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

instead of allocating each xt_counter individually, allocate 4k chunks
and then use these for counter allocation requests.

This should speed up rule evaluation by increasing data locality,
also speeds up ruleset loading because we reduce calls to the percpu
allocator.

As Eric points out we can't use PAGE_SIZE, page_allocator would fail on
arches with 64k page size.
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Keeps some noise away from a followup patch.
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

On SMP we overload the packet counter (unsigned long) to contain
percpu offset.  Hide this from callers and pass xt_counters address
instead.

Preparation patch to allocate the percpu counters in page-sized batch
chunks.
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This is to facilitate converting from a singly-linked list to an array
of elements.
Signed-off-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

During nfhook traversal we only need a very small subset of
nf_hook_ops members.

We need:
- next element
- hook function to call
- hook function priv argument

Bridge netfilter also needs 'thresh'; can be obtained via ->orig_ops.

nf_hook_entry struct is now 32 bytes on x86_64.

A followup patch will turn the run-time list into an array that only
stores hook functions plus their priv arguments, eliminating the ->next
element.
Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This allows easier future refactoring.
Signed-off-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

nf_defrag modules for ipv4 and ipv6 export an empty stub function.
Any module that needs the defragmentation hooks registered simply 'calls'
this empty function to create a phony module dependency -- modprobe will
then load the defrag module too.

This extends netfilter ipv4/ipv6 defragmentation modules to delay the hook
registration until the functionality is requested within a network namespace
instead of module load time for all namespaces.

Hooks are only un-registered on module unload or when a namespace that used
such defrag functionality exits.

We have to use struct net for this as the register hooks can be called
before netns initialization here from the ipv4/ipv6 conntrack module
init path.

There is no unregister functionality support, defrag will always be
active once it was requested inside a net namespace.

The reason is that defrag has impact on nft and iptables rulesets
(without defrag we might see framents).
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This switch (default on) can be used to disable automatic registration
of connection tracking functionality in newly created network
namespaces.

This means that when net namespace goes down (or the tracker protocol
module is unloaded) we *might* have to unregister the hooks.

We can either add another per-netns variable that tells if
the hooks got registered by default, or, alternatively, just call
the protocol _put() function and have the callee deal with a possible
'extra' put() operation that doesn't pair with a get() one.

This uses the latter approach, i.e. a put() without a get has no effect.

Conntrack is still enabled automatically regardless of the new sysctl
setting if the new net namespace requires connection tracking, e.g. when
NAT rules are created.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This makes use of nf_ct_netns_get/put added in previous patch.
We add get/put functions to nf_conntrack_l3proto structure, ipv4 and ipv6
then implement use-count to track how many users (nft or xtables modules)
have a dependency on ipv4 and/or ipv6 connection tracking functionality.

When count reaches zero, the hooks are unregistered.

This delays activation of connection tracking inside a namespace until
stateful firewall rule or nat rule gets added.

This patch breaks backwards compatibility in the sense that connection
tracking won't be active anymore when the protocol tracker module is
loaded.  This breaks e.g. setups that ctnetlink for flow accounting and
the like, without any '-m conntrack' packet filter rules.

Followup patch restores old behavour and makes new delayed scheme
optional via sysctl.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

so that conntrack core will add the needed hooks in this namespace.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

MASQUERADE, S/DNAT and REDIRECT already call functions that depend on the
conntrack module.

However, since the conntrack hooks are now registered in a lazy fashion
(i.e., only when needed) a symbol reference is not enough.

Thus, when something is added to a nat table, make sure that it will see
packets by calling nf_ct_netns_get() which will register the conntrack
hooks in the current netns.

An alternative would be to add these dependencies to the NAT table.

However, that has problems when using non-modular builds -- we might
register e.g. ipv6 conntrack before its initcall has run, leading to NULL
deref crashes since its per-netns storage has not yet been allocated.

Adding the dependency in the modules instead has the advantage that nat
table also does not register its hooks until rules are added.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

currently aliased to try_module_get/_put.
Will be changed in next patch when we add functions to make use of ->net
argument to store usercount per l3proto tracker.

This is needed to avoid registering the conntrack hooks in all netns and
later only enable connection tracking in those that need conntrack.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

since adf05168 ("netfilter: remove ip_conntrack* sysctl compat code")
the only user (ipv4 tracker) sets this to an empty stub function.

After this change nf_ct_l3proto_pernet_register() is also empty,
but this will change in a followup patch to add conditional register
of the hooks.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

CONFIG_NF_CT_PROTO_UDPLITE is no more a tristate. When set to y,
connection tracking support for UDPlite protocol is built-in into
nf_conntrack.ko.

footprint test:
$ ls -l net/netfilter/nf_conntrack{_proto_udplite,}.ko \
        net/ipv4/netfilter/nf_conntrack_ipv4.ko \
        net/ipv6/netfilter/nf_conntrack_ipv6.ko

(builtin)|| udplite|  ipv4  |  ipv6  |nf_conntrack
---------++--------+--------+--------+--------------
none     || 432538 | 828755 | 828676 | 6141434
UDPlite  ||   -    | 829649 | 829362 | 6498204
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

CONFIG_NF_CT_PROTO_SCTP is no more a tristate. When set to y, connection
tracking support for SCTP protocol is built-in into nf_conntrack.ko.

footprint test:
$ ls -l net/netfilter/nf_conntrack{_proto_sctp,}.ko \
        net/ipv4/netfilter/nf_conntrack_ipv4.ko \
        net/ipv6/netfilter/nf_conntrack_ipv6.ko

(builtin)||  sctp  |  ipv4  |  ipv6  | nf_conntrack
---------++--------+--------+--------+--------------
none     || 498243 | 828755 | 828676 | 6141434
SCTP     ||   -    | 829254 | 829175 | 6547872
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

CONFIG_NF_CT_PROTO_DCCP is no more a tristate. When set to y, connection
tracking support for DCCP protocol is built-in into nf_conntrack.ko.

footprint test:
$ ls -l net/netfilter/nf_conntrack{_proto_dccp,}.ko \
        net/ipv4/netfilter/nf_conntrack_ipv4.ko \
        net/ipv6/netfilter/nf_conntrack_ipv6.ko

(builtin)||  dccp  |  ipv4  |  ipv6  | nf_conntrack
---------++--------+--------+--------+--------------
none     || 469140 | 828755 | 828676 | 6141434
DCCP     ||   -    | 830566 | 829935 | 6533526
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

To allow usage of enum ip_conntrack_dir in include/net/netns/conntrack.h,
this patch encloses #include <linux/netfilter.h> in a #ifndef __KERNEL__
directive, so that compiler errors caused by unwanted inclusion of
include/linux/netfilter.h are avoided.
In addition, #include <linux/netfilter/nf_conntrack_common.h> line has
been added to resolve correctly CTINFO2DIR macro.
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Mikko Rapeli <mikko.rapeli@iki.fi>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Simon Horman says:

====================
IPVS Updates for v4.10

please consider these enhancements to the IPVS for v4.10.

* Decrement the IP ttl in all the modes in order to prevent infinite
  route loops. Thanks to Dwip Banerjee.
* Use IS_ERR_OR_NULL macro. Clean-up from Gao Feng.
====================
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>