linux.git/net/core/skbuff.c, branch v6.15

net-timestamp: COMPLETION timestamp on packet tx completion

2025-03-25T16:48:05+00:00

Add SOF_TIMESTAMPING_TX_COMPLETION, for requesting a software timestamp
when hardware reports a packet completed.

Completion tstamp is useful for Bluetooth, as hardware timestamps do not
exist in the HCI specification except for ISO packets, and the hardware
has a queue where packets may wait.  In this case the software SND
timestamp only reflects the kernel-side part of the total latency
(usually small) and queue length (usually 0 unless HW buffers
congested), whereas the completion report time is more informative of
the true latency.

It may also be useful in other cases where HW TX timestamps cannot be
obtained and user wants to estimate an upper bound to when the TX
probably happened.

Signed-off-by: Pauli Virtanen 
Reviewed-by: Willem de Bruijn 
Signed-off-by: Luiz Augusto von Dentz

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

2025-02-27T18:20:58+00:00

Cross-merge networking fixes after downstream PR (net-6.14-rc5).

Conflicts:

drivers/net/ethernet/cadence/macb_main.c
  fa52f15c745c ("net: cadence: macb: Synchronize stats calculations")
  75696dd0fd72 ("net: cadence: macb: Convert to get_stats64")
https://lore.kernel.org/20250224125848.68ee63e5@canb.auug.org.au

Adjacent changes:

drivers/net/ethernet/intel/ice/ice_sriov.c
  79990cf5e7ad ("ice: Fix deinitializing VF in error path")
  a203163274a4 ("ice: simplify VF MSI-X managing")

net/ipv4/tcp.c
  18912c520674 ("tcp: devmem: don't write truncated dmabuf CMSGs to userspace")
  297d389e9e5b ("net: prefix devmem specific helpers")

net/mptcp/subflow.c
  8668860b0ad3 ("mptcp: reset when MPTCP opts are dropped after join")
  c3349a22c200 ("mptcp: consolidate subflow cleanup")

Signed-off-by: Jakub Kicinski

net: skbuff: introduce napi_skb_cache_get_bulk()

2025-02-27T13:03:14+00:00

Add a function to get an array of skbs from the NAPI percpu cache.
It's supposed to be a drop-in replacement for
kmem_cache_alloc_bulk(skbuff_head_cache, GFP_ATOMIC) and
xdp_alloc_skb_bulk(GFP_ATOMIC). The difference (apart from the
requirement to call it only from the BH) is that it tries to use
as many NAPI cache entries for skbs as possible, and allocate new
ones only if needed.

The logic is as follows:

* there is enough skbs in the cache: decache them and return to the
  caller;
* not enough: try refilling the cache first. If there is now enough
  skbs, return;
* still not enough: try allocating skbs directly to the output array
  with %GFP_ZERO, maybe we'll be able to get some. If there's now
  enough, return;
* still not enough: return as many as we were able to obtain.

Most of times, if called from the NAPI polling loop, the first one will
be true, sometimes (rarely) the second one. The third and the fourth --
only under heavy memory pressure.
It can save significant amounts of CPU cycles if there are GRO cycles
and/or Tx completion cycles (anything that descends to
napi_skb_cache_put()) happening on this CPU.

Tested-by: Daniel Xu 
Reviewed-by: Toke Høiland-Jørgensen 
Signed-off-by: Alexander Lobakin 
Signed-off-by: Paolo Abeni

ipvs: Always clear ipvs_property flag in skb_scrub_packet()

2025-02-25T12:15:17+00:00

We found an issue when using bpf_redirect with ipvs NAT mode after
commit ff70202b2d1a ("dev_forward_skb: do not scrub skb mark within
the same name space"). Particularly, we use bpf_redirect to return
the skb directly back to the netif it comes from, i.e., xnet is
false in skb_scrub_packet(), and then ipvs_property is preserved
and SNAT is skipped in the rx path.

ipvs_property has been already cleared when netns is changed in
commit 2b5ec1a5f973 ("netfilter/ipvs: clear ipvs_property flag when
SKB net namespace changed"). This patch just clears it in spite of
netns.

Fixes: 2b5ec1a5f973 ("netfilter/ipvs: clear ipvs_property flag when SKB net namespace changed")
Signed-off-by: Philo Lu 
Acked-by: Julian Anastasov 
Link: https://patch.msgid.link/20250222033518.126087-1-lulie@linux.alibaba.com
Signed-off-by: Paolo Abeni

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

2025-02-21T23:59:47+00:00

Martin KaFai Lau says:

====================
pull-request: bpf-next 2025-02-20

We've added 19 non-merge commits during the last 8 day(s) which contain
a total of 35 files changed, 1126 insertions(+), 53 deletions(-).

The main changes are:

1) Add TCP_RTO_MAX_MS support to bpf_set/getsockopt, from Jason Xing

2) Add network TX timestamping support to BPF sock_ops, from Jason Xing

3) Add TX metadata Launch Time support, from Song Yoong Siang

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next:
  igc: Add launch time support to XDP ZC
  igc: Refactor empty frame insertion for launch time support
  net: stmmac: Add launch time support to XDP ZC
  selftests/bpf: Add launch time request to xdp_hw_metadata
  xsk: Add launch time hardware offload support to XDP Tx metadata
  selftests/bpf: Add simple bpf tests in the tx path for timestamping feature
  bpf: Support selective sampling for bpf timestamping
  bpf: Add BPF_SOCK_OPS_TSTAMP_SENDMSG_CB callback
  bpf: Add BPF_SOCK_OPS_TSTAMP_ACK_CB callback
  bpf: Add BPF_SOCK_OPS_TSTAMP_SND_HW_CB callback
  bpf: Add BPF_SOCK_OPS_TSTAMP_SND_SW_CB callback
  bpf: Add BPF_SOCK_OPS_TSTAMP_SCHED_CB callback
  net-timestamp: Prepare for isolating two modes of SO_TIMESTAMPING
  bpf: Disable unsafe helpers in TX timestamping callbacks
  bpf: Prevent unsafe access to the sock fields in the BPF timestamping callback
  bpf: Prepare the sock_ops ctx and call bpf prog for TX timestamping
  bpf: Add networking timestamping support to bpf_get/setsockopt()
  selftests/bpf: Add rto max for bpf_setsockopt test
  bpf: Support TCP_RTO_MAX_MS for bpf_setsockopt
====================

Link: https://patch.msgid.link/20250221022104.386462-1-martin.lau@linux.dev
Signed-off-by: Jakub Kicinski

bpf: Add BPF_SOCK_OPS_TSTAMP_ACK_CB callback

2025-02-20T22:29:43+00:00

Support the ACK case for bpf timestamping.

Add a new sock_ops callback, BPF_SOCK_OPS_TSTAMP_ACK_CB. This
callback will occur at the same timestamping point as the user
space's SCM_TSTAMP_ACK. The BPF program can use it to get the
same SCM_TSTAMP_ACK timestamp without modifying the user-space
application.

This patch extends txstamp_ack to two bits: 1 stands for
SO_TIMESTAMPING mode, 2 bpf extension.

Signed-off-by: Jason Xing 
Signed-off-by: Martin KaFai Lau 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20250220072940.99994-10-kerneljasonxing@gmail.com

bpf: Add BPF_SOCK_OPS_TSTAMP_SND_HW_CB callback

2025-02-20T22:29:36+00:00

Support hw SCM_TSTAMP_SND case for bpf timestamping.

Add a new sock_ops callback, BPF_SOCK_OPS_TSTAMP_SND_HW_CB. This
callback will occur at the same timestamping point as the user
space's hardware SCM_TSTAMP_SND. The BPF program can use it to
get the same SCM_TSTAMP_SND timestamp without modifying the
user-space application.

To avoid increasing the code complexity, replace SKBTX_HW_TSTAMP
with SKBTX_HW_TSTAMP_NOBPF instead of changing numerous callers
from driver side using SKBTX_HW_TSTAMP. The new definition of
SKBTX_HW_TSTAMP means the combination tests of socket timestamping
and bpf timestamping. After this patch, drivers can work under the
bpf timestamping.

Considering some drivers don't assign the skb with hardware
timestamp, this patch does the assignment and then BPF program
can acquire the hwstamp from skb directly.

Signed-off-by: Jason Xing 
Signed-off-by: Martin KaFai Lau 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20250220072940.99994-9-kerneljasonxing@gmail.com

bpf: Add BPF_SOCK_OPS_TSTAMP_SND_SW_CB callback

2025-02-20T22:29:30+00:00

Support sw SCM_TSTAMP_SND case for bpf timestamping.

Add a new sock_ops callback, BPF_SOCK_OPS_TSTAMP_SND_SW_CB. This
callback will occur at the same timestamping point as the user
space's software SCM_TSTAMP_SND. The BPF program can use it to
get the same SCM_TSTAMP_SND timestamp without modifying the
user-space application.

Based on this patch, BPF program will get the software
timestamp when the driver is ready to send the skb. In the
sebsequent patch, the hardware timestamp will be supported.

Signed-off-by: Jason Xing 
Signed-off-by: Martin KaFai Lau 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20250220072940.99994-8-kerneljasonxing@gmail.com

bpf: Add BPF_SOCK_OPS_TSTAMP_SCHED_CB callback

2025-02-20T22:29:24+00:00

Support SCM_TSTAMP_SCHED case for bpf timestamping.

Add a new sock_ops callback, BPF_SOCK_OPS_TSTAMP_SCHED_CB. This
callback will occur at the same timestamping point as the user
space's SCM_TSTAMP_SCHED. The BPF program can use it to get the
same SCM_TSTAMP_SCHED timestamp without modifying the user-space
application.

A new SKBTX_BPF flag is added to mark skb_shinfo(skb)->tx_flags,
ensuring that the new BPF timestamping and the current user
space's SO_TIMESTAMPING do not interfere with each other.

Signed-off-by: Jason Xing 
Signed-off-by: Martin KaFai Lau 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20250220072940.99994-7-kerneljasonxing@gmail.com

net-timestamp: Prepare for isolating two modes of SO_TIMESTAMPING

2025-02-20T22:29:15+00:00

No functional changes here. Only add test to see if the orig_skb
matches the usage of application SO_TIMESTAMPING.

In this series, bpf timestamping and previous socket timestamping
are implemented in the same function __skb_tstamp_tx(). To test
the socket enables socket timestamping feature, this function
skb_tstamp_tx_report_so_timestamping() is added.

In the next patch, another check for bpf timestamping feature
will be introduced just like the above report function, namely,
skb_tstamp_tx_report_bpf_timestamping(). Then users will be able
to know the socket enables either or both of features.

Signed-off-by: Jason Xing 
Signed-off-by: Martin KaFai Lau 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20250220072940.99994-6-kerneljasonxing@gmail.com