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Change the return type of ndo_set_rx_mode_async from void to int to
allow drivers to report failures back to the core stack. This is a
prerequisite for adding retry logic in the core when drivers fail to
program RX filters (e.g. bnxt VF when PF is unavailable).
All existing implementations return 0 for now, maintaining current
behavior.
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20260608154014.227538-2-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Some virtual devices like netkit (or ifb) never DMA and never touch frag
contents, they just forward the skb to another device. They are unable
to forward unreadable skbs, however, because they fail to pass TX
validation checks on dev->netmem_tx. The existing two-state
NETMEM_TX_NONE / NETMEM_TX_DMA doesn't give the TX validator enough
information to differentiate devices that will attempt DMA on the
unreadable skb from those that will simply route it untouched.
Add a third mode to the enum so drivers can indicate 1) if they have
netmem TX support, and 2) if they do, whether they are DMA-capable:
NETMEM_TX_NO_DMA - pass-through, device never DMAs
Widen dev->netmem_tx from a 1-bit field to 2 bits to fit the new value,
and declare netkit as NETMEM_TX_NO_DMA. Devmem TX support over these
devices comes in a follow-up patch.
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
Link: https://patch.msgid.link/20260514-tcp-dm-netkit-v5-2-408c59b91e66@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Convert netkit driver from ndo_set_rx_mode to ndo_set_rx_mode_async.
The netkit driver's set_multicast_list is a no-op, presumably
for the same reason as the one in dummy? (fake multicast ability)
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20260416185712.2155425-13-sdf@fomichev.me
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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When userspace reads a single mode netkit device via RTM_GETLINK,
it receives IFLA_NETKIT_SCRUB=NETKIT_SCRUB_DEFAULT attribute from
netkit_fill_info(). If that attribute is echoed back to recreate
the device, the seen_scrub presence check in netkit_new_link()
causes creation to fail with -EOPNOTSUPP. Since it has no meaning
for single devices at this point, just don't dump it.
Fixes: 481038960538 ("netkit: Add single device mode for netkit")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260410072334.548232-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Enable support for AF_XDP applications to operate on a netkit device.
The goal is that AF_XDP applications can natively consume AF_XDP
from network namespaces. The use-case from Cilium side is to support
Kubernetes KubeVirt VMs through QEMU's AF_XDP backend. KubeVirt is a
virtual machine management add-on for Kubernetes which aims to provide
a common ground for virtualization. KubeVirt spawns the VMs inside
Kubernetes Pods which reside in their own network namespace just like
regular Pods.
Raw QEMU AF_XDP backend example with eth0 being a physical device with
16 queues where netkit is bound to the last queue (for multi-queue RSS
context can be used if supported by the driver):
# ethtool -X eth0 start 0 equal 15
# ethtool -X eth0 start 15 equal 1 context new
# ethtool --config-ntuple eth0 flow-type ether \
src 00:00:00:00:00:00 \
src-mask ff:ff:ff:ff:ff:ff \
dst $mac dst-mask 00:00:00:00:00:00 \
proto 0 proto-mask 0xffff action 15
[ ... setup BPF/XDP prog on eth0 to steer into shared xsk map ... ]
# ip netns add foo
# ip link add numrxqueues 2 nk type netkit single
# ynl --family netdev --output-json --do queue-create \
--json "{"ifindex": $(ifindex nk), "type": "rx", \
"lease": { "ifindex": $(ifindex eth0), \
"queue": { "type": "rx", "id": 15 } } }"
{'id': 1}
# ip link set nk netns foo
# ip netns exec foo ip link set lo up
# ip netns exec foo ip link set nk up
# ip netns exec foo qemu-system-x86_64 \
-kernel $kernel \
-drive file=${image_name},index=0,media=disk,format=raw \
-append "root=/dev/sda rw console=ttyS0" \
-cpu host \
-m $memory \
-enable-kvm \
-device virtio-net-pci,netdev=net0,mac=$mac \
-netdev af-xdp,ifname=nk,id=net0,mode=native,queues=1,start-queue=1,inhibit=on,map-path=$dir/xsks_map \
-nographic
We have tested the above against a dual-port Nvidia ConnectX-6 (mlx5)
100G NIC with successful network connectivity out of QEMU. An earlier
iteration of this work was presented at LSF/MM/BPF [0] and more
recently at LPC [1].
For getting to a first starting point to connect all things with
KubeVirt, bind mounting the xsk map from Cilium into the VM launcher
Pod which acts as a regular Kubernetes Pod while not perfect, is not
a big problem given its out of reach from the application sitting
inside the VM (and some of the control plane aspects are baked in
the launcher Pod already), so the isolation barrier is still the VM.
Eventually the goal is to have a XDP/XSK redirect extension where
there is no need to have the xsk map, and the BPF program can just
derive the target xsk through the queue where traffic was received
on.
The exposure through netkit is because Cilium should not act as a
proxy handing out xsk sockets. Existing applications expect a netdev
from kernel side and should not need to rewrite just to implement
against a CNI's protocol. Also, all the memory should not be accounted
against Cilium but rather the application Pod itself which is consuming
AF_XDP. Further, on up/downgrades we expect the data plane to being
completely decoupled from the control plane; if Cilium would own the
sockets that would be disruptive. Another use-case which opens up and
is regularly asked from users would be to have DPDK applications on
top of AF_XDP in regular Kubernetes Pods.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: David Wei <dw@davidwei.uk>
Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://bpfconf.ebpf.io/bpfconf2025/bpfconf2025_material/lsfmmbpf_2025_netkit_borkmann.pdf [0]
Link: https://lpc.events/event/19/contributions/2275/ [1]
Link: https://patch.msgid.link/20260402231031.447597-14-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Add a netdevice notifier in netkit to watch for NETDEV_UNREGISTER events.
If the target device is indeed NETREG_UNREGISTERING and previously leased
a queue to a netkit device, then collect the related netkit devices and
batch-unregister_netdevice_many() them.
If this were not done, then the netkit device would hold a reference on
the physical device preventing it from going away. However, in case of
both io_uring zero-copy as well as AF_XDP this situation is handled
gracefully and the allocated resources are torn down.
In the case where mentioned infra is used through netkit, the applications
have a reference on netkit, and netkit in turn holds a reference on the
physical device. In order to have netkit release the reference on the
physical device, we need such watcher to then unregister the netkit ones.
This is generally quite similar to the dependency handling in case of
tunnels (e.g. vxlan bound to a underlying netdev) where the tunnel device
gets removed along with the physical device.
# ip a
[...]
4: enp10s0f0np0: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default qlen 1000
link/ether e8:eb:d3:a3:43:f6 brd ff:ff:ff:ff:ff:ff
inet 10.0.0.2/24 scope global enp10s0f0np0
valid_lft forever preferred_lft forever
[...]
8: nk@NONE: <BROADCAST,MULTICAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
[...]
# rmmod mlx5_ib
# rmmod mlx5_core
[...]
[ 309.261822] mlx5_core 0000:0a:00.0 mlx5_0: Port: 1 Link DOWN
[ 344.235236] mlx5_core 0000:0a:00.1: E-Switch: Unload vfs: mode(LEGACY), nvfs(0), necvfs(0), active vports(0)
[ 344.246948] mlx5_core 0000:0a:00.1: E-Switch: Disable: mode(LEGACY), nvfs(0), necvfs(0), active vports(0)
[ 344.463754] mlx5_core 0000:0a:00.1: E-Switch: Disable: mode(LEGACY), nvfs(0), necvfs(0), active vports(0)
[ 344.770155] mlx5_core 0000:0a:00.1: E-Switch: cleanup
[...]
# ip a
[...]
[ both enp10s0f0np0 and nk gone ]
[...]
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: David Wei <dw@davidwei.uk>
Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260402231031.447597-13-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Implement rtnl_link_ops->alloc that allows the number of rx queues to be
set when netkit is created. By default, netkit has only a single rxq (and
single txq). The number of queues is deliberately not allowed to be changed
via ethtool -L and is fixed for the lifetime of a netkit instance.
For netkit device creation, numrxqueues with larger than one rxq can be
specified. These rxqs are leasable to real rxqs in physical netdevs:
ip link add type netkit peer numrxqueues 64 # for device pair
ip link add numrxqueues 64 type netkit single # for single device
The limit of numrxqueues for netkit is currently set to 1024, which allows
leasing multiple real rxqs from physical netdevs.
The implementation of ndo_queue_create() adds a new rxq during the queue
lease operation. We allow to create queues either in single device mode
or for the case of dual device mode for the netkit peer device which gets
placed into the target network namespace. For dual device mode the lease
against the primary device does not make sense for the targeted use cases,
and therefore gets rejected.
We also need to add a lockdep class for netkit, such that lockdep does
not trip over us, similarly done as in commit 0bef512012b1 ("net: add
netdev_lockdep_set_classes() to virtual drivers").
This is also the last missing bit to netkit for supporting io_uring with
zero-copy mode [0]. Up until this point it was not possible to consume the
latter out of containers or Kubernetes Pods where applications are in their
own network namespace.
io_uring example with eth0 being a physical device with 16 queues where
netkit is bound to the last queue, iou-zcrx.c is binary from selftests;
ethtool configuration (tcp-data-split, hds_thresh, RSS, flow steering)
is done on the physical device by the control plane; here, flow steering
to that queue is based on the service VIP:port of the server utilizing
io_uring:
# ethtool -X eth0 start 0 equal 15
# ethtool -X eth0 start 15 equal 1 context new
# ethtool --config-ntuple eth0 flow-type tcp4 dst-ip 1.2.3.4 dst-port 5000 action 15
# ip netns add foo
# ip link add type netkit peer numrxqueues 2
# ynl --family netdev --output-json --do queue-create \
--json "{"ifindex": $(ifindex nk0), "type": "rx", \
"lease": { "ifindex": $(ifindex eth0), \
"queue": { "type": "rx", "id": 15 } } }"
{'id': 1}
# ip link set nk0 netns foo
# ip link set nk1 up
# ip netns exec foo ip link set lo up
# ip netns exec foo ip link set nk0 up
# ip netns exec foo ip addr add 1.2.3.4/32 dev nk0
[ ... setup routing etc to get external traffic into the netns ... ]
# ip netns exec foo ./iou-zcrx -s -p 5000 -i nk0 -q 1
Remote io_uring client:
# ./iou-zcrx -c -h 1.2.3.4 -p 5000 -l 12840 -z 65536
We have tested the above against a Broadcom BCM957504 (bnxt_en) 100G NIC,
supporting TCP header/data split.
Similarly, this also works for devmem which we tested using ncdevmem:
# ip netns exec foo ./ncdevmem -s 1.2.3.4 -l -p 5000 -f nk0 -t 1 -q 1
And on the remote client:
# ./ncdevmem -s 1.2.3.4 -p 5000 -f eth0
For Cilium, the plan is to open up support for the various memory providers
for regular Kubernetes Pods when Cilium is configured with netkit datapath
mode.
Signed-off-by: David Wei <dw@davidwei.uk>
Co-developed-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://kernel-recipes.org/en/2024/schedule/efficient-zero-copy-networking-using-io_uring [0]
Link: https://patch.msgid.link/20260402231031.447597-12-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Add a single device mode for netkit instead of netkit pairs. The primary
target for the paired devices is to connect network namespaces, of course,
and support has been implemented in projects like Cilium [0]. For the rxq
leasing the plan is to support two main scenarios related to single device
mode:
* For the use-case of io_uring zero-copy, the control plane can either
set up a netkit pair where the peer device can perform rxq leasing which
is then tied to the lifetime of the peer device, or the control plane
can use a regular netkit pair to connect the hostns to a Pod/container
and dynamically add/remove rxq leasing through a single device without
having to interrupt the device pair. In the case of io_uring, the memory
pool is used as skb non-linear pages, and thus the skb will go its way
through the regular stack into netkit. Things like the netkit policy when
no BPF is attached or skb scrubbing etc apply as-is in case the paired
devices are used, or if the backend memory is tied to the single device
and traffic goes through a paired device.
* For the use-case of AF_XDP, the control plane needs to use netkit in the
single device mode. The single device mode currently enforces only a
pass policy when no BPF is attached, and does not yet support BPF link
attachments for AF_XDP. skbs sent to that device get dropped at the
moment. Given AF_XDP operates at a lower layer of the stack tying this
to the netkit pair did not make sense. In future, the plan is to allow
BPF at the XDP layer which can: i) process traffic coming from the AF_XDP
application (e.g. QEMU with AF_XDP backend) to filter egress traffic or
to push selected egress traffic up to the single netkit device to the
local stack (e.g. DHCP requests), and ii) vice-versa skbs sent to the
single netkit into the AF_XDP application (e.g. DHCP replies). Also,
the control-plane can dynamically manage rxq leasing for the single
netkit device without having to interrupt (e.g. down/up cycle) the main
netkit pair for the Pod which has traffic going in and out.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: David Wei <dw@davidwei.uk>
Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Jordan Rife <jordan@jrife.io>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://docs.cilium.io/en/stable/operations/performance/tuning/#netkit-device-mode [0]
Link: https://patch.msgid.link/20260402231031.447597-11-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
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Instead of a comment, just use two cachline groups to document the intent
for members often accessed in fast or slow path.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: David Wei <dw@davidwei.uk>
Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20251031212103.310683-11-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Use attach_type in bpf_link to replace the location field, and
remove location field in netkit_link.
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20250710032038.888700-8-chen.dylane@linux.dev
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Attach_type will be set when a link is created by user. It is better to
record attach_type in bpf_link generically and have it available
universally for all link types. So add the attach_type field in bpf_link
and move the sleepable field to avoid unnecessary gap padding.
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20250710032038.888700-2-chen.dylane@linux.dev
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With ipvs_reset() now done unconditionally in skb_scrub_packet()
we would then call the former twice netkit_prep_forward(). Thus
remove the now unnecessary explicit call.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20250225212927.69271-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Add two helper functions - rtnl_newlink_link_net() and
rtnl_newlink_peer_net() for netns fallback logic. Peer netns falls back
to link netns, and link netns falls back to source netns.
Convert the use of params->net in netdevice drivers to one of the helper
functions for clarity.
Signed-off-by: Xiao Liang <shaw.leon@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250219125039.18024-4-shaw.leon@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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There are 4 net namespaces involved when creating links:
- source netns - where the netlink socket resides,
- target netns - where to put the device being created,
- link netns - netns associated with the device (backend),
- peer netns - netns of peer device.
Currently, two nets are passed to newlink() callback - "src_net"
parameter and "dev_net" (implicitly in net_device). They are set as
follows, depending on netlink attributes in the request.
+------------+-------------------+---------+---------+
| peer netns | IFLA_LINK_NETNSID | src_net | dev_net |
+------------+-------------------+---------+---------+
| | absent | source | target |
| absent +-------------------+---------+---------+
| | present | link | link |
+------------+-------------------+---------+---------+
| | absent | peer | target |
| present +-------------------+---------+---------+
| | present | peer | link |
+------------+-------------------+---------+---------+
When IFLA_LINK_NETNSID is present, the device is created in link netns
first and then moved to target netns. This has some side effects,
including extra ifindex allocation, ifname validation and link events.
These could be avoided if we create it in target netns from
the beginning.
On the other hand, the meaning of src_net parameter is ambiguous. It
varies depending on how parameters are passed. It is the effective
link (or peer netns) by design, but some drivers ignore it and use
dev_net instead.
To provide more netns context for drivers, this patch packs existing
newlink() parameters, along with the source netns, link netns and peer
netns, into a struct. The old "src_net" is renamed to "net" to avoid
confusion with real source netns, and will be deprecated later. The use
of src_net are converted to params->net trivially.
Signed-off-by: Xiao Liang <shaw.leon@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250219125039.18024-3-shaw.leon@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Allow the user to configure needed_{head,tail}room for both netkit
devices. The idea is similar to 163e529200af ("veth: implement
ndo_set_rx_headroom") with the difference that the two parameters
can be specified upon device creation. By default the current behavior
stays as is which is needed_{head,tail}room is 0.
In case of Cilium, for example, the netkit devices are not enslaved
into a bridge or openvswitch device (rather, BPF-based redirection
is used out of tcx), and as such these parameters are not propagated
into the Pod's netns via peer device.
Given Cilium can run in vxlan/geneve tunneling mode (needed_headroom)
and/or be used in combination with WireGuard (needed_{head,tail}room),
allow the Cilium CNI plugin to specify these two upon netkit device
creation.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/bpf/20241220234658.490686-1-daniel@iogearbox.net
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Currently rtnl_link_get_net_ifla() gets called twice when we create
peer devices, once in rtnl_add_peer_net() and once in each ->newlink()
implementation.
This looks safer, however, it leads to a classic Time-of-Check to
Time-of-Use (TOCTOU) bug since IFLA_NET_NS_PID is very dynamic. And
because of the lack of checking error pointer of the second call, it
also leads to a kernel crash as reported by syzbot.
Fix this by getting rid of the second call, which already becomes
redudant after Kuniyuki's work. We have to propagate the result of the
first rtnl_link_get_net_ifla() down to each ->newlink().
Reported-by: syzbot+21ba4d5adff0b6a7cfc6@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=21ba4d5adff0b6a7cfc6
Fixes: 0eb87b02a705 ("veth: Set VETH_INFO_PEER to veth_link_ops.peer_type.")
Fixes: 6b84e558e95d ("vxcan: Set VXCAN_INFO_PEER to vxcan_link_ops.peer_type.")
Fixes: fefd5d082172 ("netkit: Set IFLA_NETKIT_PEER_INFO to netkit_link_ops.peer_type.")
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20241129212519.825567-1-xiyou.wangcong@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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For per-netns RTNL, we need to prefetch the peer device's netns.
Let's set rtnl_link_ops.peer_type and accordingly remove duplicated
validation in ->newlink().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241108004823.29419-9-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Jakub suggested to rely on netlink policy validation via NLA_POLICY_MAX()
instead of open-coding it. netkit_check_mode() is a candidate which can
be simplified through this as well aside from the netkit scrubbing one.
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20241004101335.117711-2-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Jordan reported that when running Cilium with netkit in per-endpoint-routes
mode, network policy misclassifies traffic. In this direct routing mode
of Cilium which is used in case of GKE/EKS/AKS, the Pod's BPF program to
enforce policy sits on the netkit primary device's egress side.
The issue here is that in case of netkit's netkit_prep_forward(), it will
clear meta data such as skb->mark and skb->priority before executing the
BPF program. Thus, identity data stored in there from earlier BPF programs
(e.g. from tcx ingress on the physical device) gets cleared instead of
being made available for the primary's program to process. While for traffic
egressing the Pod via the peer device this might be desired, this is
different for the primary one where compared to tcx egress on the host
veth this information would be available.
To address this, add a new parameter for the device orchestration to
allow control of skb->mark and skb->priority scrubbing, to make the two
accessible from BPF (and eventually leave it up to the program to scrub).
By default, the current behavior is retained. For netkit peer this also
enables the use case where applications could cooperate/signal intent to
the BPF program.
Note that struct netkit has a 4 byte hole between policy and bundle which
is used here, in other words, struct netkit's first cacheline content used
in fast-path does not get moved around.
Fixes: 35dfaad7188c ("netkit, bpf: Add bpf programmable net device")
Reported-by: Jordan Rife <jrife@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://github.com/cilium/cilium/issues/34042
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20241004101335.117711-1-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Merge in late fixes to prepare for the 6.12 net-next PR.
No conflicts or adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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During the introduction of struct bpf_net_context handling for
XDP-redirect, the netkit driver has been missed, which also requires it
because NETKIT_REDIRECT invokes skb_do_redirect() which is accessing the
per-CPU variables. Otherwise we see the following crash:
BUG: kernel NULL pointer dereference, address: 0000000000000038
bpf_redirect()
netkit_xmit()
dev_hard_start_xmit()
Set the bpf_net_context before invoking netkit_xmit() program within the
netkit driver.
Fixes: 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.")
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20240912155620.1334587-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2024-09-11
We've added 12 non-merge commits during the last 16 day(s) which contain
a total of 20 files changed, 228 insertions(+), 30 deletions(-).
There's a minor merge conflict in drivers/net/netkit.c:
00d066a4d4ed ("netdev_features: convert NETIF_F_LLTX to dev->lltx")
d96608794889 ("netkit: Disable netpoll support")
The main changes are:
1) Enable bpf_dynptr_from_skb for tp_btf such that this can be used
to easily parse skbs in BPF programs attached to tracepoints,
from Philo Lu.
2) Add a cond_resched() point in BPF's sock_hash_free() as there have
been several syzbot soft lockup reports recently, from Eric Dumazet.
3) Fix xsk_buff_can_alloc() to account for queue_empty_descs which
got noticed when zero copy ice driver started to use it,
from Maciej Fijalkowski.
4) Move the xdp:xdp_cpumap_kthread tracepoint before cpumap pushes skbs
up via netif_receive_skb_list() to better measure latencies,
from Daniel Xu.
5) Follow-up to disable netpoll support from netkit, from Daniel Borkmann.
6) Improve xsk selftests to not assume a fixed MAX_SKB_FRAGS of 17 but
instead gather the actual value via /proc/sys/net/core/max_skb_frags,
also from Maciej Fijalkowski.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next:
sock_map: Add a cond_resched() in sock_hash_free()
selftests/bpf: Expand skb dynptr selftests for tp_btf
bpf: Allow bpf_dynptr_from_skb() for tp_btf
tcp: Use skb__nullable in trace_tcp_send_reset
selftests/bpf: Add test for __nullable suffix in tp_btf
bpf: Support __nullable argument suffix for tp_btf
bpf, cpumap: Move xdp:xdp_cpumap_kthread tracepoint before rcv
selftests/xsk: Read current MAX_SKB_FRAGS from sysctl knob
xsk: Bump xsk_queue::queue_empty_descs in xp_can_alloc()
tcp_bpf: Remove an unused parameter for bpf_tcp_ingress()
bpf, sockmap: Correct spelling skmsg.c
netkit: Disable netpoll support
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
====================
Link: https://patch.msgid.link/20240911211525.13834-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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NETIF_F_LLTX can't be changed via Ethtool and is not a feature,
rather an attribute, very similar to IFF_NO_QUEUE (and hot).
Free one netdev_features_t bit and make it a "hot" private flag.
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Follow-up to 45160cebd6ac ("net: veth: Disable netpoll support") to
also disable netpoll for netkit interfaces. Same conditions apply
here as well.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Breno Leitao <leitao@debian.org>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/eab2d69ba2f4c260aef62e4ff0d803e9f60c2c5d.1724414250.git.daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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When running Cilium connectivity test suite with netkit in L2 mode, we
found that compared to tcx a few tests were failing which pushed traffic
into an L7 proxy sitting in host namespace. The problem in particular is
around the invocation of eth_type_trans() in netkit.
In case of tcx, this is run before the tcx ingress is triggered inside
host namespace and thus if the BPF program uses the bpf_skb_change_type()
helper the newly set type is retained. However, in case of netkit, the
late eth_type_trans() invocation overrides the earlier decision from the
BPF program which eventually leads to the test failure.
Instead of eth_type_trans(), split out the relevant parts, meaning, reset
of mac header and call to eth_skb_pkt_type() before the BPF program is run
in order to have the same behavior as with tcx, and refactor a small helper
called eth_skb_pull_mac() which is run in case it's passed up the stack
where the mac header must be pulled. With this all connectivity tests pass.
Fixes: 35dfaad7188c ("netkit, bpf: Add bpf programmable net device")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20240524163619.26001-2-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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When running Cilium connectivity test suite with netkit in L2 mode, we
found that it is expected to be able to specify a custom MAC address for
the devices, in particular, cilium-cni obtains the specified MAC address
by querying the endpoint and sets the MAC address of the interface inside
the Pod. Thus, fix the missing support in netkit for L2 mode.
Fixes: 35dfaad7188c ("netkit, bpf: Add bpf programmable net device")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20240524163619.26001-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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We want to be able to run rtnl_fill_ifinfo() under RCU protection
instead of RTNL in the future.
This patch prepares dev_get_iflink() and nla_put_iflink()
to run either with RTNL or RCU held.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The IFLA_NETKIT_PEER_INFO attribute can only be used during device
creation, but not via changelink callback. Hence reject it there.
Fixes: 35dfaad7188c ("netkit, bpf: Add bpf programmable net device")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/e86a277a1e8d3b19890312779e42f790b0605ea4.1701115314.git.daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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ndo_get_peer_dev is used in tcx BPF fast path, therefore make use of
indirect call wrapper and therefore optimize the bpf_redirect_peer()
internal handling a bit. Add a small skb_get_peer_dev() wrapper which
utilizes the INDIRECT_CALL_1() macro instead of open coding.
Future work could potentially add a peer pointer directly into struct
net_device in future and convert veth and netkit over to use it so
that eventually ndo_get_peer_dev can be removed.
Co-developed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20231114004220.6495-7-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Add dev->tstats traffic accounting to netkit. The latter contains per-CPU
RX and TX counters.
The dev's TX counters are bumped upon pass/unspec as well as redirect
verdicts, in other words, on everything except for drops.
The dev's RX counters are bumped upon successful __netif_rx(), as well
as from skb_do_redirect() (not part of this commit here).
Using dev->lstats with having just a single packets/bytes counter and
inferring one another's RX counters from the peer dev's lstats is not
possible given skb_do_redirect() can also bump the device's stats.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20231114004220.6495-4-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Remove the explicit NULLing of active/peer pointers and rely on the
implicit one done at net device allocation.
Suggested-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20231026094106.1505892-2-razor@blackwall.org
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This work adds a new, minimal BPF-programmable device called "netkit"
(former PoC code-name "meta") we recently presented at LSF/MM/BPF. The
core idea is that BPF programs are executed within the drivers xmit routine
and therefore e.g. in case of containers/Pods moving BPF processing closer
to the source.
One of the goals was that in case of Pod egress traffic, this allows to
move BPF programs from hostns tcx ingress into the device itself, providing
earlier drop or forward mechanisms, for example, if the BPF program
determines that the skb must be sent out of the node, then a redirect to
the physical device can take place directly without going through per-CPU
backlog queue. This helps to shift processing for such traffic from softirq
to process context, leading to better scheduling decisions/performance (see
measurements in the slides).
In this initial version, the netkit device ships as a pair, but we plan to
extend this further so it can also operate in single device mode. The pair
comes with a primary and a peer device. Only the primary device, typically
residing in hostns, can manage BPF programs for itself and its peer. The
peer device is designated for containers/Pods and cannot attach/detach
BPF programs. Upon the device creation, the user can set the default policy
to 'pass' or 'drop' for the case when no BPF program is attached.
Additionally, the device can be operated in L3 (default) or L2 mode. The
management of BPF programs is done via bpf_mprog, so that multi-attach is
supported right from the beginning with similar API and dependency controls
as tcx. For details on the latter see commit 053c8e1f235d ("bpf: Add generic
attach/detach/query API for multi-progs"). tc BPF compatibility is provided,
so that existing programs can be easily migrated.
Going forward, we plan to use netkit devices in Cilium as the main device
type for connecting Pods. They will be operated in L3 mode in order to
simplify a Pod's neighbor management and the peer will operate in default
drop mode, so that no traffic is leaving between the time when a Pod is
brought up by the CNI plugin and programs attached by the agent.
Additionally, the programs we attach via tcx on the physical devices are
using bpf_redirect_peer() for inbound traffic into netkit device, hence the
latter is also supporting the ndo_get_peer_dev callback. Similarly, we use
bpf_redirect_neigh() for the way out, pushing from netkit peer to phys device
directly. Also, BIG TCP is supported on netkit device. For the follow-up
work in single device mode, we plan to convert Cilium's cilium_host/_net
devices into a single one.
An extensive test suite for checking device operations and the BPF program
and link management API comes as BPF selftests in this series.
Co-developed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://github.com/borkmann/iproute2/tree/pr/netkit
Link: http://vger.kernel.org/bpfconf2023_material/tcx_meta_netdev_borkmann.pdf (24ff.)
Link: https://lore.kernel.org/r/20231024214904.29825-2-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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