net: Remove unneeded NULL check for the allocated ifnet

Change 4787572d0580 made if_alloc_domain() never fail, then also do the
wrappers if_alloc(), if_alloc_dev(), and if_gethandle().

No functiona

net: Remove unneeded NULL check for the allocated ifnet

Change 4787572d0580 made if_alloc_domain() never fail, then also do the
wrappers if_alloc(), if_alloc_dev(), and if_gethandle().

No functional change intended.

Reviewed by: kp, imp, glebius, stevek
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D45740

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sys: Use mbufq_empty instead of comparing mbufq_len against 0

Reviewed by: bz, emaste
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D43338

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

if_epair: do not transmit packets that exceed the interface MTU

While if_epair has no issues doing this we should drop those packets
anyway, because it improves the fidelity of the automated tests.

if_epair: do not transmit packets that exceed the interface MTU

While if_epair has no issues doing this we should drop those packets
anyway, because it improves the fidelity of the automated tests.

Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D40397

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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

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net: replace IFF_KNOWSEPOCH with IFF_NEEDSEPOCH

Expect that drivers call into the network stack with the net epoch
entered. This has already been the fact since early 2020. The net
interrupts, that

net: replace IFF_KNOWSEPOCH with IFF_NEEDSEPOCH

Expect that drivers call into the network stack with the net epoch
entered. This has already been the fact since early 2020. The net
interrupts, that are marked with INTR_TYPE_NET, were entering epoch
since 511d1afb6bf. For the taskqueues there is NET_TASK_INIT() and
all drivers that were known back in 2020 we marked with it in
6c3e93cb5a4. However in e87c4940156 we took conservative approach
and preferred to opt-in rather than opt-out for the epoch.

This change not only reverts e87c4940156 but adds a safety belt to
avoid panicing with INVARIANTS if there is a missed driver. With
INVARIANTS we will run in_epoch() check, print a warning and enter
the net epoch. A driver that prints can be quickly fixed with the
IFF_NEEDSEPOCH flag, but better be augmented to properly enter the
epoch itself.

Note on TCP LRO: it is a backdoor to enter the TCP stack bypassing
some layers of net stack, ignoring either old IFF_KNOWSEPOCH or the
new IFF_NEEDSEPOCH. But the tcp_lro_flush_all() asserts the presence
of network epoch. Indeed, all NIC drivers that support LRO already
provide the epoch, either with help of INTR_TYPE_NET or just running
NET_EPOCH_ENTER() in their code.

Reviewed by: zlei, gallatin, erj
Differential Revision: https://reviews.freebsd.org/D39510

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if_epair: also remove vlan metadata from mbufs

We already remove mbuf tags from packets transitting an if_epair, but we
didn't remove vlan metadata.
In certain configurations this could lead to unex

if_epair: also remove vlan metadata from mbufs

We already remove mbuf tags from packets transitting an if_epair, but we
didn't remove vlan metadata.
In certain configurations this could lead to unexpected vlan tags
turning up on the rx side.

PR: 270736
Reviewed by: markj
MFC after: 1 week
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D39482

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epair: Remove unneeded includes and sort some of the rest

No functional change intended.

MFC after: 1 week

epair: Simplify the transmit path and address lost wakeups

epairs currently shuttle all transmitted packets through a single global
taskqueue thread. To hand packets over to the taskqueue thread, e

epair: Simplify the transmit path and address lost wakeups

epairs currently shuttle all transmitted packets through a single global
taskqueue thread. To hand packets over to the taskqueue thread, each
epair maintains a pair of ring buffers and a lockless scheme for
notifying the thread of pending work. The implementation can lead to
lost wakeups, causing to-be-transmitted packets to end up stuck in the
queue.

Rather than extending the existing scheme, simply replace it with a
linked list protected by a mutex, and use the mutex to synchronize
wakeups of the taskqueue thread. This appears to give equivalent or
better throughput with >= 16 producer threads and eliminates the lost
wakeups.

Reviewed by: kp
MFC after: 1 week
Sponsored by: Klara, Inc.
Sponsored by: Modirum MDPay
Differential Revision: https://reviews.freebsd.org/D38843

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epair: Avoid loading m_flags into a short

The m_flags field of struct mbuf is 24 bits wide and so gets truncated
in a couple of places in the epair code. Instead of preserving the
entire flag set,

epair: Avoid loading m_flags into a short

The m_flags field of struct mbuf is 24 bits wide and so gets truncated
in a couple of places in the epair code. Instead of preserving the
entire flag set, just remember whether M_BCAST or M_MCAST is set.

MFC after: 1 week
Sponsored by: Klara, Inc.

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ifnet/API: Move struct ifnet definition to a <net/if_private.h>

Hide the ifnet structure definition, no user serviceable parts inside,
it's a netstack implementation detail. Include it temporarily

ifnet/API: Move struct ifnet definition to a <net/if_private.h>

Hide the ifnet structure definition, no user serviceable parts inside,
it's a netstack implementation detail. Include it temporarily in
<net/if_var.h> until all drivers are updated to use the accessors
exclusively.

Reviewed by: glebius
Sponsored by: Juniper Networks, Inc.
Differential Revision: https://reviews.freebsd.org/D38046

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if_epair: fix build with RSS

Sponsored by: Rubicon Communications, LLC ("Netgate")

if_epair: refactor interface creation and enqueue code.

* Factor out queue selection (epair_select_queue()) and mbuf
preparation (epair_prepare_mbuf()) from epair_menq(). It simplifies
epair_menq(

if_epair: refactor interface creation and enqueue code.

* Factor out queue selection (epair_select_queue()) and mbuf
preparation (epair_prepare_mbuf()) from epair_menq(). It simplifies
epair_menq() implementation and reduces the amount of dependencies
on the neighbouring epair.
* Use dedicated epair_set_state() instead of 2-lines copy-paste
* Factor out unit selection code (epair_handle_unit()) from
epair_clone_create(). It simplifies the clone creation logic.

Reviewed By: kp
Differential Revision: https://reviews.freebsd.org/D36689

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if_clone: migrate some consumers to the new KPI.

Convert most of the cloner customers who require custom params
to the new if_clone KPI.

Reviewed by: kp
Differential Revision: https://reviews.free

if_clone: migrate some consumers to the new KPI.

Convert most of the cloner customers who require custom params
to the new if_clone KPI.

Reviewed by: kp
Differential Revision: https://reviews.freebsd.org/D36636
MFC after: 2 weeks

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epair: deduplicate interface allocation code #1

Simplify epair_clone_create() and epair_clone_destroy() by
factoring out epair softc allocation / desctruction and
interface setup/teardown into sep

epair: deduplicate interface allocation code #1

Simplify epair_clone_create() and epair_clone_destroy() by
factoring out epair softc allocation / desctruction and
interface setup/teardown into separate functions.

Reviewed By: kp, zlei.huang_gmail.com
Differential Revision: https://reviews.freebsd.org/D36614
MFC after: 2 weeks

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epair: unbind prior to returning to userspace

If 'options RSS' is set we bind the epair tasks to different CPUs. We
must take care to not keep the current thread bound to the last CPU when
we return

epair: unbind prior to returning to userspace

If 'options RSS' is set we bind the epair tasks to different CPUs. We
must take care to not keep the current thread bound to the last CPU when
we return to userspace.

MFC after: 1 week
Sponsored by: Orange Business Services

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epair: fix set but not used warning

If 'options RSS' is set.

MFC after: 1 week
Sponsored by: Orange Business Services

if_epair: build fix

66acf7685b failed to build on riscv (and mips). This is because the
atomic_testandset_int() (and friends) functions do not exist there.
Happily those platforms do have the long v

if_epair: build fix

66acf7685b failed to build on riscv (and mips). This is because the
atomic_testandset_int() (and friends) functions do not exist there.
Happily those platforms do have the long variant, so switch to that.

PR: 262571
MFC after: 3 days

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if_epair: fix race condition on multi-core systems

As an unwanted side effect of the performance improvements in
24f0bfbad57b9, epair interfaces stop forwarding traffic on higher
load levels when ru

if_epair: fix race condition on multi-core systems

As an unwanted side effect of the performance improvements in
24f0bfbad57b9, epair interfaces stop forwarding traffic on higher
load levels when running on multi-core systems.

This happens due to a race condition in the logic that decides when to
place work in the task queue(s) responsible for processing the content
of ring buffers.

In order to fix this, a field named state is added to the epair_queue
structure. This field is used by the affected functions to signal each
other that something happened in the underlying ring buffers that might
require work to be scheduled in task queue(s), replacing the existing
logic, which relied on checking if ring buffers are empty or not.

epair_menq() does:
- set BIT_MBUF_QUEUED
- queue mbuf
- if testandset BIT_QUEUE_TASK:
enqueue task

epair_tx_start_deferred() does:
- swap ring buffers
- process mbufs
- clear BIT_QUEUE_TASK
- if testandclear BIT_MBUF_QUEUED
enqueue task

PR: 262571
Reported by: Johan Hendriks <joh.hendriks@gmail.com>
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D34569

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if_epair: fix build with RSS and INET or INET6 disabled

Reviewed by: kp
MFC after: 1 week

if_epair: Use ANSI C definition

This fixes -Werror=strict-prototypes from gcc9

Sponsored by: The FreeBSD Foundation

if_epair: implement fanout

Allow multiple cores to be used to process if_epair traffic. We do this
(if RSS is enabled) based on the RSS hash of the incoming packet. This
allows us to distribute the

if_epair: implement fanout

Allow multiple cores to be used to process if_epair traffic. We do this
(if RSS is enabled) based on the RSS hash of the incoming packet. This
allows us to distribute the load over multiple cores, rather than
sending everything to the same one.

We also switch from swi_sched() to taskqueues, which also contributes to
better throughput.

Benchmark results:
With net.isr.maxthreads=-1

Setup A: (cc0 - bridge0 - epair0a) (epair0b - bridge1 - cc1)

Before 627 Kpps
After (no RSS) 1.198 Mpps
After (RSS) 3.148 Mpps

Setup B: (cc0 - bridge0 - epaira0) (epair0b - vnet jail - epair1a) (epair1b - bridge1 - cc1)

Before 7.705 Kpps
After (no RSS) 1.017 Mpps
After (RSS) 2.083 Mpps

MFC after: 3 weeks
Sponsored by: Orange Business Services
Differential Revision: https://reviews.freebsd.org/D33731

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if_epair: Also mark the flag of pair b with IFF_KNOWSEPOCH

Reviewed by: kp
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D33210

if_epair: ifdef vars only used with ALTQ

Sponsored by: Rubicon Communications, LLC ("Netgate")

epair: remove "All rights reserved"

Remove "All rights reserved" from The FreeBSD Foundation owned
copyrights on epair code and documentation.

Approved by: emaste (FreeBSD Foundation)