linux.git/include/net/ip.h, branch v6.12.80

net: use dst_dev_rcu() in sk_setup_caps()

2026-01-08T09:15:01+00:00

[ Upstream commit 99a2ace61b211b0be861b07fbaa062fca4b58879 ]

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 
[Harshit: Backport to 6.12.y, resolve conflict due to missing commit:
22d6c9eebf2e ("net: Unexport shared functions for DCCP.")  in 6.12.y]
Signed-off-by: Harshit Mogalapalli 
Signed-off-by: Greg Kroah-Hartman

ipv4: adopt dst_dev, skb_dst_dev and skb_dst_dev_net[_rcu]

2025-10-23T14:20:45+00:00

[ Upstream commit a74fc62eec155ca5a6da8ff3856f3dc87fe24558 ]

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 
Stable-dep-of: 833d4313bc1e ("mptcp: reset blackhole on success with non-loopback ifaces")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ipv4: Convert ip_route_input() to dscp_t.

2025-03-07T17:25:29+00:00

[ Upstream commit 7e863e5db6185b1add0df4cb01b31a4ed1c4b738 ]

Pass a dscp_t variable to ip_route_input(), instead of a plain u8, to
prevent accidental setting of ECN bits in ->flowi4_tos.

Callers of ip_route_input() to consider are:

  * input_action_end_dx4_finish() and input_action_end_dt4() in
    net/ipv6/seg6_local.c. These functions set the tos parameter to 0,
    which is already a valid dscp_t value, so they don't need to be
    adjusted for the new prototype.

  * icmp_route_lookup(), which already has a dscp_t variable to pass as
    parameter. We just need to remove the inet_dscp_to_dsfield()
    conversion.

  * br_nf_pre_routing_finish(), ip_options_rcv_srr() and ip4ip6_err(),
    which get the DSCP directly from IPv4 headers. Define a helper to
    read the .tos field of struct iphdr as dscp_t, so that these
    function don't have to do the conversion manually.

While there, declare *iph as const in br_nf_pre_routing_finish(),
declare its local variables in reverse-christmas-tree order and move
the "err = ip_route_input()" assignment out of the conditional to avoid
checkpatch warning.

Signed-off-by: Guillaume Nault 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/e9d40781d64d3d69f4c79ac8a008b8d67a033e8d.1727807926.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski 
Stable-dep-of: 27843ce6ba3d ("ipvlan: ensure network headers are in skb linear part")
Signed-off-by: Sasha Levin

ipv4: use RCU protection in ip_dst_mtu_maybe_forward()

2025-02-21T13:01:40+00:00

[ Upstream commit 071d8012869b6af352acca346ade13e7be90a49f ]

ip_dst_mtu_maybe_forward() must use RCU protection to make
sure the net structure it reads does not disappear.

Fixes: f87c10a8aa1e8 ("ipv4: introduce ip_dst_mtu_maybe_forward and protect forwarding path against pmtu spoofing")
Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250205155120.1676781-4-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv4: Unmask upper DSCP bits in get_rttos()

2024-08-31T16:44:51+00:00

The function is used by a few socket types to retrieve the TOS value
with which to perform the FIB lookup for packets sent through the socket
(flowi4_tos). If a DS field was passed using the IP_TOS control message,
then it is used. Otherwise the one specified via the IP_TOS socket
option.

Unmask the upper DSCP bits so that in the future the lookup could be
performed according to the full DSCP value.

Signed-off-by: Ido Schimmel 
Reviewed-by: Guillaume Nault 
Signed-off-by: David S. Miller

icmp: icmp_msgs_per_sec and icmp_msgs_burst sysctls become per netns

2024-08-30T18:14:06+00:00

Previous patch made ICMP rate limits per netns, it makes sense
to allow each netns to change the associated sysctl.

Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20240829144641.3880376-4-edumazet@google.com
Signed-off-by: Jakub Kicinski

icmp: move icmp_global.credit and icmp_global.stamp to per netns storage

2024-08-30T18:14:06+00:00

Host wide ICMP ratelimiter should be per netns, to provide better isolation.

Following patch in this series makes the sysctl per netns.

Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20240829144641.3880376-3-edumazet@google.com
Signed-off-by: Jakub Kicinski

icmp: change the order of rate limits

2024-08-30T18:14:06+00:00

ICMP messages are ratelimited :

After the blamed commits, the two rate limiters are applied in this order:

1) host wide ratelimit (icmp_global_allow())

2) Per destination ratelimit (inetpeer based)

In order to avoid side-channels attacks, we need to apply
the per destination check first.

This patch makes the following change :

1) icmp_global_allow() checks if the host wide limit is reached.
   But credits are not yet consumed. This is deferred to 3)

2) The per destination limit is checked/updated.
   This might add a new node in inetpeer tree.

3) icmp_global_consume() consumes tokens if prior operations succeeded.

This means that host wide ratelimit is still effective
in keeping inetpeer tree small even under DDOS.

As a bonus, I removed icmp_global.lock as the fast path
can use a lock-free operation.

Fixes: c0303efeab73 ("net: reduce cycles spend on ICMP replies that gets rate limited")
Fixes: 4cdf507d5452 ("icmp: add a global rate limitation")
Reported-by: Keyu Man 
Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Cc: Jesper Dangaard Brouer 
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20240829144641.3880376-2-edumazet@google.com
Signed-off-by: Jakub Kicinski

net: remove NULL-pointer net parameter in ip_metrics_convert

2024-06-05T09:06:00+00:00

When I was doing some experiments, I found that when using the first
parameter, namely, struct net, in ip_metrics_convert() always triggers NULL
pointer crash. Then I digged into this part, realizing that we can remove
this one due to its uselessness.

Signed-off-by: Jason Xing 
Reviewed-by: Simon Horman 
Signed-off-by: David S. Miller

inet: introduce dst_rtable() helper

2024-05-01T01:32:38+00:00

I added dst_rt6_info() in commit
e8dfd42c17fa ("ipv6: introduce dst_rt6_info() helper")

This patch does a similar change for IPv4.

Instead of (struct rtable *)dst casts, we can use :

 #define dst_rtable(_ptr) \
             container_of_const(_ptr, struct rtable, dst)

Patch is smaller than IPv6 one, because IPv4 has skb_rtable() helper.

Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Reviewed-by: Sabrina Dubroca 
Link: https://lore.kernel.org/r/20240429133009.1227754-1-edumazet@google.com
Signed-off-by: Jakub Kicinski