bonding/xfrm: use real_dev instead of slave_dev

Rather than requiring every hw crypto capable NIC driver to do a check for
slave_dev being set, set real_dev in the xfrm layer and xso ini

bonding/xfrm: use real_dev instead of slave_dev

Rather than requiring every hw crypto capable NIC driver to do a check for
slave_dev being set, set real_dev in the xfrm layer and xso init time, and
then override it in the bonding driver as needed. Then NIC drivers can
always use real_dev, and at the same time, we eliminate the use of a
variable name that probably shouldn't have been used in the first place,
particularly given recent current events.

CC: Boris Pismenny <borisp@mellanox.com>
CC: Saeed Mahameed <saeedm@mellanox.com>
CC: Leon Romanovsky <leon@kernel.org>
CC: Jay Vosburgh <j.vosburgh@gmail.com>
CC: Veaceslav Falico <vfalico@gmail.com>
CC: Andy Gospodarek <andy@greyhouse.net>
CC: "David S. Miller" <davem@davemloft.net>
CC: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
CC: Jakub Kicinski <kuba@kernel.org>
CC: Steffen Klassert <steffen.klassert@secunet.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: netdev@vger.kernel.org
Suggested-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

xfrm: bail early on slave pass over skb

This is prep work for initial support of bonding hardware encryption
pass-through support. The bonding driver will fill in the slave_dev
point

xfrm: bail early on slave pass over skb

This is prep work for initial support of bonding hardware encryption
pass-through support. The bonding driver will fill in the slave_dev
pointer, and we use that to know not to skb_push() again on a given
skb that was already processed on the bond device.

CC: Jay Vosburgh <j.vosburgh@gmail.com>
CC: Veaceslav Falico <vfalico@gmail.com>
CC: Andy Gospodarek <andy@greyhouse.net>
CC: "David S. Miller" <davem@davemloft.net>
CC: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
CC: Jakub Kicinski <kuba@kernel.org>
CC: Steffen Klassert <steffen.klassert@secunet.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: netdev@vger.kernel.org
CC: intel-wired-lan@lists.osuosl.org
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

xfrm: Fix double ESP trailer insertion in IPsec crypto offload.

During IPsec performance testing, we see bad ICMP checksum. The error packet
has duplicated ESP trailer due to double vali

xfrm: Fix double ESP trailer insertion in IPsec crypto offload.

During IPsec performance testing, we see bad ICMP checksum. The error packet
has duplicated ESP trailer due to double validate_xmit_xfrm calls. The first call
is from ip_output, but the packet cannot be sent because
netif_xmit_frozen_or_stopped is true and the packet gets dev_requeue_skb. The second
call is from NET_TX softirq. However after the first call, the packet already
has the ESP trailer.

Fix by marking the skb with XFRM_XMIT bit after the packet is handled by
validate_xmit_xfrm to avoid duplicate ESP trailer insertion.

Fixes: f6e27114a60a ("net: Add a xfrm validate function to validate_xmit_skb")
Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Reviewed-by: Boris Pismenny <borisp@mellanox.com>
Reviewed-by: Raed Salem <raeds@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

xfrm: do pskb_pull properly in __xfrm_transport_prep

For transport mode, when ipv6 nexthdr is set, the packet format might
be like:

-----------------------------------------

xfrm: do pskb_pull properly in __xfrm_transport_prep

For transport mode, when ipv6 nexthdr is set, the packet format might
be like:

----------------------------------------------------
| | dest | | | | ESP | ESP |
| IP6 hdr| opts.| ESP | TCP | Data | Trailer | ICV |
----------------------------------------------------

and in __xfrm_transport_prep():

pskb_pull(skb, skb->mac_len + sizeof(ip6hdr) + x->props.header_len);

it will pull the data pointer to the wrong position, as it missed the
nexthdrs/dest opts.

This patch is to fix it by using:

pskb_pull(skb, skb_transport_offset(skb) + x->props.header_len);

as we can be sure transport_header points to ESP header at that moment.

It also fixes a panic when packets with ipv6 nexthdr are sent over
esp6 transport mode:

[ 100.473845] kernel BUG at net/core/skbuff.c:4325!
[ 100.478517] RIP: 0010:__skb_to_sgvec+0x252/0x260
[ 100.494355] Call Trace:
[ 100.494829] skb_to_sgvec+0x11/0x40
[ 100.495492] esp6_output_tail+0x12e/0x550 [esp6]
[ 100.496358] esp6_xmit+0x1d5/0x260 [esp6_offload]
[ 100.498029] validate_xmit_xfrm+0x22f/0x2e0
[ 100.499604] __dev_queue_xmit+0x589/0x910
[ 100.502928] ip6_finish_output2+0x2a5/0x5a0
[ 100.503718] ip6_output+0x6c/0x120
[ 100.505198] xfrm_output_resume+0x4bf/0x530
[ 100.508683] xfrm6_output+0x3a/0xc0
[ 100.513446] inet6_csk_xmit+0xa1/0xf0
[ 100.517335] tcp_sendmsg+0x27/0x40
[ 100.517977] sock_sendmsg+0x3e/0x60
[ 100.518648] __sys_sendto+0xee/0x160

Fixes: c35fe4106b92 ("xfrm: Add mode handlers for IPsec on layer 2")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2020-0

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2020-03-28

1) Use kmem_cache_zalloc() instead of kmem_cache_alloc()
in xfrm_state_alloc(). From Huang Zijiang.

2) esp_output_fill_trailer() is the same in IPv4 and IPv6,
so share this function to avoide code duplcation.
From Raed Salem.

3) Add offload support for esp beet mode.
From Xin Long.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

xfrm: add prep for esp beet mode offload

Like __xfrm_transport/mode_tunnel_prep(), this patch is to add
__xfrm_mode_beet_prep() to fix the transport_header for gso
segments, and rese

xfrm: add prep for esp beet mode offload

Like __xfrm_transport/mode_tunnel_prep(), this patch is to add
__xfrm_mode_beet_prep() to fix the transport_header for gso
segments, and reset skb mac_len, and pull skb data to the
proto inside esp.

This patch also fixes a panic, reported by ltp:

# modprobe esp4_offload
# runltp -f net_stress.ipsec_tcp

[ 2452.780511] kernel BUG at net/core/skbuff.c:109!
[ 2452.799851] Call Trace:
[ 2452.800298] <IRQ>
[ 2452.800705] skb_push.cold.98+0x14/0x20
[ 2452.801396] esp_xmit+0x17b/0x270 [esp4_offload]
[ 2452.802799] validate_xmit_xfrm+0x22f/0x2e0
[ 2452.804285] __dev_queue_xmit+0x589/0x910
[ 2452.806264] __neigh_update+0x3d7/0xa50
[ 2452.806958] arp_process+0x259/0x810
[ 2452.807589] arp_rcv+0x18a/0x1c

It was caused by the skb going to esp_xmit with a wrong transport
header.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

esp: remove the skb from the chain when it's enqueued in cryptd_wq

Xiumei found a panic in esp offload:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000020

esp: remove the skb from the chain when it's enqueued in cryptd_wq

Xiumei found a panic in esp offload:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
RIP: 0010:esp_output_done+0x101/0x160 [esp4]
Call Trace:
? esp_output+0x180/0x180 [esp4]
cryptd_aead_crypt+0x4c/0x90
cryptd_queue_worker+0x6e/0xa0
process_one_work+0x1a7/0x3b0
worker_thread+0x30/0x390
? create_worker+0x1a0/0x1a0
kthread+0x112/0x130
? kthread_flush_work_fn+0x10/0x10
ret_from_fork+0x35/0x40

It was caused by that skb secpath is used in esp_output_done() after it's
been released elsewhere.

The tx path for esp offload is:

__dev_queue_xmit()->
validate_xmit_skb_list()->
validate_xmit_xfrm()->
esp_xmit()->
esp_output_tail()->
aead_request_set_callback(esp_output_done) <--[1]
crypto_aead_encrypt() <--[2]

In [1], .callback is set, and in [2] it will trigger the worker schedule,
later on a kernel thread will call .callback(esp_output_done), as the call
trace shows.

But in validate_xmit_xfrm():

skb_list_walk_safe(skb, skb2, nskb) {
...
err = x->type_offload->xmit(x, skb2, esp_features); [esp_xmit]
...
}

When the err is -EINPROGRESS, which means this skb2 will be enqueued and
later gets encrypted and sent out by .callback later in a kernel thread,
skb2 should be removed fromt skb chain. Otherwise, it will get processed
again outside validate_xmit_xfrm(), which could release skb secpath, and
cause the panic above.

This patch is to remove the skb from the chain when it's enqueued in
cryptd_wq. While at it, remove the unnecessary 'if (!skb)' check.

Fixes: 3dca3f38cfb8 ("xfrm: Separate ESP handling from segmentation for GRO packets.")
Reported-by: Xiumei Mu <xmu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

xfrm: handle NETDEV_UNREGISTER for xfrm device

This patch to handle the asynchronous unregister
device event so the device IPsec offload resources
could be cleanly released.

xfrm: handle NETDEV_UNREGISTER for xfrm device

This patch to handle the asynchronous unregister
device event so the device IPsec offload resources
could be cleanly released.

Fixes: e4db5b61c572 ("xfrm: policy: remove pcpu policy cache")
Signed-off-by: Raed Salem <raeds@mellanox.com>
Reviewed-by: Boris Pismenny <borisp@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

net: xfrm: use skb_list_walk_safe helper for gso segments

This is converts xfrm segment iteration to use the new function, keeping
the flow of the existing code as intact as possible. On

net: xfrm: use skb_list_walk_safe helper for gso segments

This is converts xfrm segment iteration to use the new function, keeping
the flow of the existing code as intact as possible. One case is very
straight-forward, whereas the other case has some more subtle code that
likes to peak at ->next and relink skbs. By keeping the variables the
same as before, we can upgrade this code with minimal surgery required.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2019-0

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2019-07-05

1) A lot of work to remove indirections from the xfrm code.
From Florian Westphal.

2) Fix a WARN_ON with ipv6 that triggered because of a
forgotten break statement. From Florian Westphal.

3) Remove xfrmi_init_net, it is not needed.
From Li RongQing.

Please pull or let me know if there are problems.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

xfrm: remove get_mtu indirection from xfrm_type

esp4_get_mtu and esp6_get_mtu are exactly the same, the only difference
is a single sizeof() (ipv4 vs. ipv6 header).

Merge both i

xfrm: remove get_mtu indirection from xfrm_type

esp4_get_mtu and esp6_get_mtu are exactly the same, the only difference
is a single sizeof() (ipv4 vs. ipv6 header).

Merge both into xfrm_state_mtu() and remove the indirection.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it u

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

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 as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

xfrm: store xfrm_mode directly, not its address

This structure is now only 4 bytes, so its more efficient
to cache a copy rather than its address.

No significant size difference

xfrm: store xfrm_mode directly, not its address

This structure is now only 4 bytes, so its more efficient
to cache a copy rather than its address.

No significant size difference in allmodconfig vmlinux.

With non-modular kernel that has all XFRM options enabled, this
series reduces vmlinux image size by ~11kb. All xfrm_mode
indirections are gone and all modes are built-in.

before (ipsec-next master):
text data bss dec filename
21071494 7233140 11104324 39408958 vmlinux.master

after this series:
21066448 7226772 11104324 39397544 vmlinux.patched

With allmodconfig kernel, the size increase is only 362 bytes,
even all the xfrm config options removed in this series are
modular.

before:
text data bss dec filename
15731286 6936912 4046908 26715106 vmlinux.master

after this series:
15731492 6937068 4046908 26715468 vmlinux

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

xfrm: remove xmit indirection from xfrm_mode

There are only two versions (tunnel and transport). The ip/ipv6 versions
are only differ in sizeof(iphdr) vs ipv6hdr.

Place this in

xfrm: remove xmit indirection from xfrm_mode

There are only two versions (tunnel and transport). The ip/ipv6 versions
are only differ in sizeof(iphdr) vs ipv6hdr.

Place this in the core and use x->outer_mode->encap type to call the
correct adjustment helper.

Before:
text data bss dec filename
15730311 6937008 4046908 26714227 vmlinux

After:
15730428 6937008 4046908 26714344 vmlinux

(about 117 byte increase)

v2: use family from x->outer_mode, not inner

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

xfrm: gso partial offload support

This patch introduces support for gso partial ESP offload.

Signed-off-by: Boris Pismenny <borisp@mellanox.com>
Signed-off-by: Raed Salem <raeds

xfrm: gso partial offload support

This patch introduces support for gso partial ESP offload.

Signed-off-by: Boris Pismenny <borisp@mellanox.com>
Signed-off-by: Raed Salem <raeds@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

net: dev: rename queue selection helpers.

With the following patches, we are going to use __netdev_pick_tx() in
many modules. Rename it to netdev_pick_tx(), to make it clear is
a pub

net: dev: rename queue selection helpers.

With the following patches, we are going to use __netdev_pick_tx() in
many modules. Rename it to netdev_pick_tx(), to make it clear is
a public API.

Also rename the existing netdev_pick_tx() to netdev_core_pick_tx(),
to avoid name clashes.

Suggested-by: Eric Dumazet <edumazet@google.com>
Suggested-by: David Miller <davem@davemloft.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net: use skb_sec_path helper in more places

skb_sec_path gains 'const' qualifier to avoid
xt_policy.c: 'skb_sec_path' discards 'const' qualifier from pointer target type

same re

net: use skb_sec_path helper in more places

skb_sec_path gains 'const' qualifier to avoid
xt_policy.c: 'skb_sec_path' discards 'const' qualifier from pointer target type

same reasoning as previous conversions: Won't need to touch these
spots anymore when skb->sp is removed.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2018-1

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2018-10-01

1) Make xfrmi_get_link_net() static to silence a sparse warning.
From Wei Yongjun.

2) Remove a unused esph pointer definition in esp_input().
From Haishuang Yan.

3) Allow the NIC driver to quietly refuse xfrm offload
in case it does not support it, the SA is created
without offload in this case.
From Shannon Nelson.

Please pull or let me know if there are problems.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net: Add and use skb_mark_not_on_list().

An SKB is not on a list if skb->next is NULL.

Codify this convention into a helper function and use it
where we are dequeueing an SKB an

net: Add and use skb_mark_not_on_list().

An SKB is not on a list if skb->next is NULL.

Codify this convention into a helper function and use it
where we are dequeueing an SKB and need to mark it as such.

Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

xfrm: allow driver to quietly refuse offload

If the "offload" attribute is used to create an IPsec SA
and the .xdo_dev_state_add() fails, the SA creation fails.
However, if the "offl

xfrm: allow driver to quietly refuse offload

If the "offload" attribute is used to create an IPsec SA
and the .xdo_dev_state_add() fails, the SA creation fails.
However, if the "offload" attribute is used on a device that
doesn't offer it, the attribute is quietly ignored and the SA
is created without an offload.

Along the same line of that second case, it would be good to
have a way for the device to refuse to offload an SA without
failing the whole SA creation. This patch adds that feature
by allowing the driver to return -EOPNOTSUPP as a signal that
the SA may be fine, it just can't be offloaded.

This allows the user a little more flexibility in requesting
offloads and not needing to know every detail at all times about
each specific NIC when trying to create SAs.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

xfrm: don't check offload_handle for nonzero

The offload_handle should be an opaque data cookie for the driver
to use, much like the data cookie for a timer or alarm callback.
Thus,

xfrm: don't check offload_handle for nonzero

The offload_handle should be an opaque data cookie for the driver
to use, much like the data cookie for a timer or alarm callback.
Thus, the XFRM stack should not be checking for non-zero, because
the driver might use that to store an array reference, which could
be zero, or some other zero but meaningful value.

We can remove the checks for non-zero because there are plenty
other attributes also being checked to see if there is an offload
in place for the SA in question.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

xfrm: policy: remove pcpu policy cache

Kristian Evensen says:
In a project I am involved in, we are running ipsec (Strongswan) on
different mt7621-based routers. Each router is c

xfrm: policy: remove pcpu policy cache

Kristian Evensen says:
In a project I am involved in, we are running ipsec (Strongswan) on
different mt7621-based routers. Each router is configured as an
initiator and has around ~30 tunnels to different responders (running
on misc. devices). Before the flow cache was removed (kernel 4.9), we
got a combined throughput of around 70Mbit/s for all tunnels on one
router. However, we recently switched to kernel 4.14 (4.14.48), and
the total throughput is somewhere around 57Mbit/s (best-case). I.e., a
drop of around 20%. Reverting the flow cache removal restores, as
expected, performance levels to that of kernel 4.9.

When pcpu xdst exists, it has to be validated first before it can be
used.

A negative hit thus increases cost vs. no-cache.

As number of tunnels increases, hit rate decreases so this pcpu caching
isn't a viable strategy.

Furthermore, the xdst cache also needs to run with BH off, so when
removing this the bh disable/enable pairs can be removed too.

Kristian tested a 4.14.y backport of this change and reported
increased performance:

In our tests, the throughput reduction has been reduced from around -20%
to -5%. We also see that the overall throughput is independent of the
number of tunnels, while before the throughput was reduced as the number
of tunnels increased.

Reported-by: Kristian Evensen <kristian.evensen@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

show more ...

xfrm: Extend the output_mark to support input direction and masking.

We already support setting an output mark at the xfrm_state,
unfortunately this does not support the input direction

xfrm: Extend the output_mark to support input direction and masking.

We already support setting an output mark at the xfrm_state,
unfortunately this does not support the input direction and
masking the marks that will be applied to the skb. This change
adds support applying a masked value in both directions.

The existing XFRMA_OUTPUT_MARK number is reused for this purpose
and as it is now bi-directional, it is renamed to XFRMA_SET_MARK.

An additional XFRMA_SET_MARK_MASK attribute is added for setting the
mask. If the attribute mask not provided, it is set to 0xffffffff,
keeping the XFRMA_OUTPUT_MARK existing 'full mask' semantics.

Co-developed-by: Tobias Brunner <tobias@strongswan.org>
Co-developed-by: Eyal Birger <eyal.birger@gmail.com>
Co-developed-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Tobias Brunner <tobias@strongswan.org>
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>

show more ...

xfrm: Register xfrm_dev_notifier in appropriate place

Currently, driver registers it from pernet_operations::init method,
and this breaks modularity, because initialization of net namesp

xfrm: Register xfrm_dev_notifier in appropriate place

Currently, driver registers it from pernet_operations::init method,
and this breaks modularity, because initialization of net namespace
and netdevice notifiers are orthogonal actions. We don't have
per-namespace netdevice notifiers; all of them are global for all
devices in all namespaces.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net: rename skb_gso_validate_mtu -> skb_gso_validate_network_len

If you take a GSO skb, and split it into packets, will the network
length (L3 headers + L4 headers + payload) of those pa

net: rename skb_gso_validate_mtu -> skb_gso_validate_network_len

If you take a GSO skb, and split it into packets, will the network
length (L3 headers + L4 headers + payload) of those packets be small
enough to fit within a given MTU?

skb_gso_validate_mtu gives you the answer to that question. However,
we recently added to add a way to validate the MAC length of a split GSO
skb (L2+L3+L4+payload), and the names get confusing, so rename
skb_gso_validate_mtu to skb_gso_validate_network_len

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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