linux-stable.git/drivers/net/netkit.c, branch linux-6.14.y

netkit: Allow for configuring needed_{head,tail}room

2025-01-06T08:48:49+00:00

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 
Reviewed-by: Jakub Kicinski 
Acked-by: Nikolay Aleksandrov 
Link: https://lore.kernel.org/bpf/20241220234658.490686-1-daniel@iogearbox.net

rtnetlink: fix double call of rtnl_link_get_net_ifla()

2024-12-03T10:29:29+00:00

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 
Signed-off-by: Cong Wang 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20241129212519.825567-1-xiyou.wangcong@gmail.com
Signed-off-by: Paolo Abeni

netkit: Set IFLA_NETKIT_PEER_INFO to netkit_link_ops.peer_type.

2024-11-12T01:26:52+00:00

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 
Reviewed-by: Eric Dumazet 
Acked-by: Nikolay Aleksandrov 
Link: https://patch.msgid.link/20241108004823.29419-9-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski

netkit: Simplify netkit mode over to use NLA_POLICY_MAX

2024-10-08T00:12:37+00:00

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 
Signed-off-by: Daniel Borkmann 
Cc: Nikolay Aleksandrov 
Acked-by: Nikolay Aleksandrov 
Link: https://lore.kernel.org/r/20241004101335.117711-2-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau

netkit: Add option for scrubbing skb meta data

2024-10-08T00:12:37+00:00

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 
Signed-off-by: Daniel Borkmann 
Cc: Nikolay Aleksandrov 
Link: https://github.com/cilium/cilium/issues/34042
Acked-by: Jakub Kicinski 
Acked-by: Nikolay Aleksandrov 
Link: https://lore.kernel.org/r/20241004101335.117711-1-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-09-15T16:13:19+00:00

Merge in late fixes to prepare for the 6.12 net-next PR.

No conflicts or adjacent changes.

Signed-off-by: Jakub Kicinski

netkit: Assign missing bpf_net_context

2024-09-14T02:49:45+00:00

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 
Acked-by: Daniel Borkmann 
Reviewed-by: Sebastian Andrzej Siewior 
Reviewed-by: Toke Høiland-Jørgensen 
Acked-by: Nikolay Aleksandrov 
Acked-by: Martin KaFai Lau 
Link: https://patch.msgid.link/20240912155620.1334587-1-leitao@debian.org
Signed-off-by: Jakub Kicinski

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2024-09-13T03:22:44+00:00

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 
====================

Link: https://patch.msgid.link/20240911211525.13834-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski

netdev_features: convert NETIF_F_LLTX to dev->lltx

2024-09-03T09:36:43+00:00

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 
Signed-off-by: Paolo Abeni

netkit: Disable netpoll support

2024-08-27T18:37:45+00:00

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 
Cc: Breno Leitao 
Cc: Nikolay Aleksandrov 
Acked-by: Nikolay Aleksandrov 
Reviewed-by: Breno Leitao 
Link: https://lore.kernel.org/r/eab2d69ba2f4c260aef62e4ff0d803e9f60c2c5d.1724414250.git.daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau