netfilter: drop bridge nf reset from nf_reset

commit 174e23810cd31
("sk_buff: drop all skb extensions on free and skb scrubbing") made napi
recycle always drop skb extensions. The additional skb_ext_del() that is
performed via nf_reset on napi skb recycle is not needed anymore.

Most nf_reset() calls in the stack are there so queued skb won't block
'rmmod nf_conntrack' indefinitely.

This removes the skb_ext_del from nf_reset, and renames it to a more
fitting nf_reset_ct().

In a few selected places, add a call to skb_ext_reset to make sure that
no active extensions remain.

I am submitting this for "net", because we're still early in the release
cycle. The patch applies to net-next too, but I think the rename causes
needless divergence between those trees.

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 3

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 or
later as published by the free software foundation

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 9 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154040.848507137@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

netfilter: kill the fake untracked conntrack objects

resurrect an old patch from Pablo Neira to remove the untracked objects.

Currently, there are four possible states of an skb wrt. conntrack.

1. No conntrack attached, ct is NULL.
2. Normal (kmem cache allocated) ct attached.
3. a template (kmalloc'd), not in any hash tables at any point in time
4. the 'untracked' conntrack, a percpu nf_conn object, tagged via
IPS_UNTRACKED_BIT in ct->status.

Untracked is supposed to be identical to case 1. It exists only
so users can check

-m conntrack --ctstate UNTRACKED vs.
-m conntrack --ctstate INVALID

e.g. attempts to set connmark on INVALID or UNTRACKED conntracks is
supposed to be a no-op.

Thus currently we need to check
ct == NULL || nf_ct_is_untracked(ct)

in a lot of places in order to avoid altering untracked objects.

The other consequence of the percpu untracked object is that all
-j NOTRACK (and, later, kfree_skb of such skbs) result in an atomic op
(inc/dec the untracked conntracks refcount).

This adds a new kernel-private ctinfo state, IP_CT_UNTRACKED, to
make the distinction instead.

The (few) places that care about packet invalid (ct is NULL) vs.
packet untracked now need to test ct == NULL vs. ctinfo == IP_CT_UNTRACKED,
but all other places can omit the nf_ct_is_untracked() check.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: merge ctinfo into nfct pointer storage area

After this change conntrack operations (lookup, creation, matching from
ruleset) only access one instead of two sk_buff cache lines.

This works for normal conntracks because those are allocated from a slab
that guarantees hw cacheline or 8byte alignment (whatever is larger)
so the 3 bits needed for ctinfo won't overlap with nf_conn addresses.

Template allocation now does manual address alignment (see previous change)
on arches that don't have sufficent kmalloc min alignment.

Some spots intentionally use skb->_nfct instead of skb_nfct() helpers,
this is to avoid undoing the skb_nfct() use when we remove untracked
conntrack object in the future.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: add and use nf_ct_set helper

Add a helper to assign a nf_conn entry and the ctinfo bits to an sk_buff.
This avoids changing code in followup patch that merges skb->nfct and
skb->nfctinfo into skb->_nfct.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: reset netfilter state when duplicating packet

We should also toss nf_bridge_info, if any -- packet is leaving via
ip_local_out, also, this skb isn't bridged -- it is a locally generated
copy. Also this avoids the need to touch this later when skb->nfct is
replaced with 'unsigned long _nfct' in followup patch.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_dup_ipv6: set again FLOWI_FLAG_KNOWN_NH at flowi6_flags

With the commit 48e8aa6e3137 ("ipv6: Set FLOWI_FLAG_KNOWN_NH at
flowi6_flags") ip6_pol_route() callers were asked to to set the
FLOWI_FLAG_KNOWN_NH properly and xt_TEE was updated accordingly,
but with the later refactor in commit bbde9fc1824a ("netfilter:
factor out packet duplication for IPv4/IPv6") the flowi6_flags
update was lost.
This commit re-add it just before the routing decision.

Fixes: bbde9fc1824a ("netfilter: factor out packet duplication for IPv4/IPv6")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

ipv4, ipv6: Pass net into ip_local_out and ip6_local_out

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Merge ip6_local_out and ip6_local_out_sk

Stop hidding the sk parameter with an inline helper function and make
all of the callers pass it, so that it is clear what the function is
doing.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: Pass net to nf_dup_ipv4 and nf_dup_ipv6

This allows them to stop guessing the network namespace with pick_net.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_dup{4, 6}: fix build error when nf_conntrack disabled

While testing various Kconfig options on another issue, I found that
the following one triggers as well on allmodconfig and nf_conntrack
disabled:

net/ipv4/netfilter/nf_dup_ipv4.c: In function ‘nf_dup_ipv4’:
net/ipv4/netfilter/nf_dup_ipv4.c:72:20: error: ‘nf_skb_duplicated’ undeclared (first use in this function)
if (this_cpu_read(nf_skb_duplicated))
[...]
net/ipv6/netfilter/nf_dup_ipv6.c: In function ‘nf_dup_ipv6’:
net/ipv6/netfilter/nf_dup_ipv6.c:66:20: error: ‘nf_skb_duplicated’ undeclared (first use in this function)
if (this_cpu_read(nf_skb_duplicated))

Fix it by including directly the header where it is defined.

Fixes: bbde9fc1824a ("netfilter: factor out packet duplication for IPv4/IPv6")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: nf_dup: fix sparse warnings

>> net/ipv4/netfilter/nft_dup_ipv4.c:29:37: sparse: incorrect type in initializer (different base types)
net/ipv4/netfilter/nft_dup_ipv4.c:29:37: expected restricted __be32 [user type] s_addr
net/ipv4/netfilter/nft_dup_ipv4.c:29:37: got unsigned int [unsigned] <noident>

>> net/ipv6/netfilter/nf_dup_ipv6.c:48:23: sparse: incorrect type in assignment (different base types)
net/ipv6/netfilter/nf_dup_ipv6.c:48:23: expected restricted __be32 [addressable] [assigned] [usertype] flowlabel
net/ipv6/netfilter/nf_dup_ipv6.c:48:23: got int

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: add nft_dup expression

This new expression uses the nf_dup engine to clone packets to a given gateway.
Unlike xt_TEE, we use an index to indicate output interface which should be
fine at this stage.

Moreover, change to the preemtion-safe this_cpu_read(nf_skb_duplicated) from
nf_dup_ipv{4,6} to silence a lockdep splat.

Based on the original tee expression from Arturo Borrero Gonzalez, although
this patch has diverted quite a bit from this initial effort due to the
change to support maps.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: factor out packet duplication for IPv4/IPv6

Extracted from the xtables TEE target. This creates two new modules for IPv4
and IPv6 that are shared between the TEE target and the new nf_tables dup
expressions.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>