linux.git/include/net/ip.h, branch v6.18.21

inet: annotate data-races around isk->inet_num

2026-03-12T11:09:50+00:00

[ Upstream commit 29252397bcc1e0a1f85e5c3bee59c325f5c26341 ]

UDP/TCP lookups are using RCU, thus isk->inet_num accesses
should use READ_ONCE() and WRITE_ONCE() where needed.

Fixes: 3ab5aee7fe84 ("net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls")
Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20260225203545.1512417-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: snmp: remove SNMP_MIB_SENTINEL

2025-09-09T01:06:21+00:00

No more user of SNMP_MIB_SENTINEL, we can remove it.

Also remove snmp_get_cpu_field[64]_batch() helpers.

Signed-off-by: Eric Dumazet 
Reviewed-by: Sabrina Dubroca 
Link: https://patch.msgid.link/20250905165813.1470708-10-edumazet@google.com
Signed-off-by: Jakub Kicinski

ipv6: snmp: do not use SNMP_MIB_SENTINEL anymore

2025-09-09T01:06:20+00:00

Use ARRAY_SIZE(), so that we know the limit at compile time.

Following patch needs this preliminary change.

Signed-off-by: Eric Dumazet 
Reviewed-by: Sabrina Dubroca 
Link: https://patch.msgid.link/20250905165813.1470708-3-edumazet@google.com
Signed-off-by: Jakub Kicinski

net: use dst_dev_rcu() in sk_setup_caps()

2025-08-30T02:36:32+00:00

Use RCU to protect accesses to dst->dev from sk_setup_caps()
and sk_dst_gso_max_size().

Also use dst_dev_rcu() in ip6_dst_mtu_maybe_forward(),
and ip_dst_mtu_maybe_forward().

ip4_dst_hoplimit() can use dst_dev_net_rcu().

Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()")
Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20250828195823.3958522-6-edumazet@google.com
Signed-off-by: Jakub Kicinski

ipv4: adopt dst_dev, skb_dst_dev and skb_dst_dev_net[_rcu]

2025-07-02T21:32:30+00:00

Use the new helpers as a first step to deal with
potential dst->dev races.

Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250630121934.3399505-8-edumazet@google.com
Signed-off-by: Jakub Kicinski

net: dst: annotate data-races around dst->expires

2025-07-02T21:32:29+00:00

(dst_entry)->expires is read and written locklessly,
add corresponding annotations.

Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250630121934.3399505-3-edumazet@google.com
Signed-off-by: Jakub Kicinski

net: ipv4: Add ip_mr_output()

2025-06-18T01:18:45+00:00

Multicast routing is today handled in the input path. Locally generated MC
packets don't hit the IPMR code today. Thus if a VXLAN remote address is
multicast, the driver needs to set an OIF during route lookup. Thus MC
routing configuration needs to be kept in sync with the VXLAN FDB and MDB.
Ideally, the VXLAN packets would be routed by the MC routing code instead.

To that end, this patch adds support to route locally generated multicast
packets. The newly-added routines do largely what ip_mr_input() and
ip_mr_forward() do: make an MR cache lookup to find where to send the
packets, and use ip_mc_output() to send each of them. When no cache entry
is found, the packet is punted to the daemon for resolution.

However, an installation that uses a VXLAN underlay netdevice for which it
also has matching MC routes, would get a different routing with this patch.
Previously, the MC packets would be delivered directly to the underlay
port, whereas now they would be MC-routed. In order to avoid this change in
behavior, introduce an IPCB flag. Only if the flag is set will
ip_mr_output() actually engage, otherwise it reverts to ip_mc_output().

This code is based on work by Roopa Prabhu and Nikolay Aleksandrov.

Signed-off-by: Roopa Prabhu
Signed-off-by: Nikolay Aleksandrov
Signed-off-by: Benjamin Poirier
Signed-off-by: Petr Machata
Reviewed-by: Ido Schimmel
Link: https://patch.msgid.link/0aadbd49330471c0f758d54afb05eb3b6e3a6b65.1750113335.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski

net: use netif_disable_lro in ipv6_add_dev

2025-04-03T22:32:08+00:00

ipv6_add_dev might call dev_disable_lro which unconditionally grabs
instance lock, so it will deadlock during NETDEV_REGISTER. Switch
to netif_disable_lro.

Make sure all callers hold the instance lock as well.

Cc: Cosmin Ratiu 
Fixes: ad7c7b2172c3 ("net: hold netdev instance lock during sysfs operations")
Signed-off-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20250401163452.622454-4-sdf@fomichev.me
Signed-off-by: Jakub Kicinski

inet: call inet6_ehashfn() once from inet6_hash_connect()

2025-03-06T23:26:02+00:00

inet6_ehashfn() being called from __inet6_check_established()
has a big impact on performance, as shown in the Tested section.

After prior patch, we can compute the hash for port 0
from inet6_hash_connect(), and derive each hash in
__inet_hash_connect() from this initial hash:

hash(saddr, lport, daddr, dport) == hash(saddr, 0, daddr, dport) + lport

Apply the same principle for __inet_check_established(),
although inet_ehashfn() has a smaller cost.

Tested:

Server: ulimit -n 40000; neper/tcp_crr -T 200 -F 30000 -6 --nolog
Client: ulimit -n 40000; neper/tcp_crr -T 200 -F 30000 -6 --nolog -c -H server

Before this patch:

  utime_start=0.286131
  utime_end=4.378886
  stime_start=11.952556
  stime_end=1991.655533
  num_transactions=1446830
  latency_min=0.001061085
  latency_max=12.075275028
  latency_mean=0.376375302
  latency_stddev=1.361969596
  num_samples=306383
  throughput=151866.56

perf top:

 50.01%  [kernel]       [k] __inet6_check_established
 20.65%  [kernel]       [k] __inet_hash_connect
 15.81%  [kernel]       [k] inet6_ehashfn
  2.92%  [kernel]       [k] rcu_all_qs
  2.34%  [kernel]       [k] __cond_resched
  0.50%  [kernel]       [k] _raw_spin_lock
  0.34%  [kernel]       [k] sched_balance_trigger
  0.24%  [kernel]       [k] queued_spin_lock_slowpath

After this patch:

  utime_start=0.315047
  utime_end=9.257617
  stime_start=7.041489
  stime_end=1923.688387
  num_transactions=3057968
  latency_min=0.003041375
  latency_max=7.056589232
  latency_mean=0.141075048    # Better latency metrics
  latency_stddev=0.526900516
  num_samples=312996
  throughput=320677.21        # 111 % increase, and 229 % for the series

perf top: inet6_ehashfn is no longer seen.

 39.67%  [kernel]       [k] __inet_hash_connect
 37.06%  [kernel]       [k] __inet6_check_established
  4.79%  [kernel]       [k] rcu_all_qs
  3.82%  [kernel]       [k] __cond_resched
  1.76%  [kernel]       [k] sched_balance_domains
  0.82%  [kernel]       [k] _raw_spin_lock
  0.81%  [kernel]       [k] sched_balance_rq
  0.81%  [kernel]       [k] sched_balance_trigger
  0.76%  [kernel]       [k] queued_spin_lock_slowpath

Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Tested-by: Jason Xing 
Reviewed-by: Jason Xing 
Link: https://patch.msgid.link/20250305034550.879255-3-edumazet@google.com
Signed-off-by: Jakub Kicinski

ipv4: remove get_rttos

2025-02-19T02:27:19+00:00

Initialize the ip cookie tos field when initializing the cookie, in
ipcm_init_sk.

The existing code inverts the standard pattern for initializing cookie
fields. Default is to initialize the field from the sk, then possibly
overwrite that when parsing cmsgs (the unlikely case).

This field inverts that, setting the field to an illegal value and
after cmsg parsing checking whether the value is still illegal and
thus should be overridden.

Be careful to always apply mask INET_DSCP_MASK, as before.

Signed-off-by: Willem de Bruijn 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20250214222720.3205500-5-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski