This converts the only path not returning drop reasons in
ip_rcv_finish_core.

Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250915091958.15382-4-atenart@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Instead of setting the drop reason to SKB_DROP_REASON_NOT_SPECIFIED
early and having to reset it each time it is overridden by a function
returned value, just set the drop reason to the expected value before
returning from ip_rcv_finish_core.

Signed-off-by: Antoine Tenart <atenart@kernel.org>
Link: https://patch.msgid.link/20250915091958.15382-3-atenart@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

udp_v4_early_demux already returns drop reasons as it either returns 0
or ip_mc_validate_source, which itself returns drop reasons. Its return
value is also already used as a drop reason itself.

Makes this explicit by making it return drop reasons.

Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250915091958.15382-2-atenart@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Currently, ip_extract_route_hint uses RTN_BROADCAST to decide
whether to use the route dst hint mechanism.

This check is too strict, as it prevents directed broadcast
routes from using the hint, resulting in poor performance
during bursts of directed broadcast traffic.

Fix this in ip_extract_route_hint and modify ip_route_use_hint
to preserve the intended behaviour.

Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250819174642.5148-2-oscmaes92@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Cross-merge networking fixes after downstream PR (net-6.16-rc5).

No conflicts.

No adjacent changes.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>

MSG_ZEROCOPY data must be copied before data is queued to local
sockets, to avoid indefinite timeout until memory release.

This test is performed by skb_orphan_frags_rx, which is called when
looping an egress skb to packet sockets, error queue or ingress path.

To preserve zerocopy for skbs that are looped to ingress but are then
forwarded to an egress device rather than delivered locally, defer
this last check until an skb enters the local IP receive path.

This is analogous to existing behavior of skb_clear_delivery_time.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250630194312.1571410-2-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

udp_v4_early_demux now returns drop reasons as it either returns 0 or
ip_mc_validate_source, which returns itself a drop reason. However its
use was not converted in ip_rcv_finish_core and the drop reason is
ignored, leading to potentially skipping increasing LINUX_MIB_IPRPFILTER
if the drop reason is SKB_DROP_REASON_IP_RPFILTER.

This is a fix and we're not converting udp_v4_early_demux to explicitly
return a drop reason to ease backports; this can be done as a follow-up.

Fixes: d46f827016d8 ("net: ip: make ip_mc_validate_source() return drop reason")
Cc: Menglong Dong <menglong8.dong@gmail.com>
Reported-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://patch.msgid.link/20250701074935.144134-1-atenart@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The "struct sock *sk" parameter in ip_rcv_finish_core is unused, which
leads the compiler to optimize it out. As a result, the
"struct sk_buff *skb" parameter is passed using x1. And this make kprobe
hard to use.

Signed-off-by: Yu Tian <tianyu2@kernelsoft.com>
Link: https://patch.msgid.link/20241231023610.1657926-1-tianyu2@kernelsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

In this commit, we make ip_route_use_hint() return drop reasons. The
drop reasons that we return are similar to what we do in
ip_route_input_slow(), and no drop reasons are added in this commit.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

In this commit, we make ip_route_input_noref() return drop reasons, which
come from ip_route_input_rcu().

We need adjust the callers of ip_route_input_noref() to make sure the
return value of ip_route_input_noref() is used properly.

The errno that ip_route_input_noref() returns comes from ip_route_input
and bpf_lwt_input_reroute in the origin logic, and we make them return
-EINVAL on error instead. In the following patch, we will make
ip_route_input() returns drop reasons too.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>