Merge branch 'net-ip-add-drop-reasons-to-input-route'

Merge branch 'net-ip-add-drop-reasons-to-input-route'

Menglong Dong says:

====================
net: ip: add drop reasons to input route

In this series, we mainly add some skb drop reasons to the input path of
ip routing, and we make the following functions return drop reasons:

  fib_validate_source()
  ip_route_input_mc()
  ip_mc_validate_source()
  ip_route_input_slow()
  ip_route_input_rcu()
  ip_route_input_noref()
  ip_route_input()
  ip_mkroute_input()
  __mkroute_input()
  ip_route_use_hint()

And following new skb drop reasons are added:

  SKB_DROP_REASON_IP_LOCAL_SOURCE
  SKB_DROP_REASON_IP_INVALID_SOURCE
  SKB_DROP_REASON_IP_LOCALNET
  SKB_DROP_REASON_IP_INVALID_DEST

Changes since v4:
- in the 6th patch: remove the unneeded "else" in ip_expire()
- in the 8th patch: delete the unneeded comment in __mkroute_input()
- in the 9th patch: replace "return 0" with "return SKB_NOT_DROPPED_YET"
  in ip_route_use_hint()

Changes since v3:
- don't refactor fib_validate_source/__fib_validate_source, and introduce
  a wrapper for fib_validate_source() instead in the 1st patch.
- some small adjustment in the 4-7 patches

Changes since v2:
- refactor fib_validate_source and __fib_validate_source to make
  fib_validate_source return drop reasons
- add the 9th and 10th patches to make this series cover the input route
  code path

Changes since v1:
- make ip_route_input_noref/ip_route_input_rcu/ip_route_input_slow return
  drop reasons, instead of passing a local variable to their function
  arguments.
====================

Link: https://patch.msgid.link/20241107125601.1076814-1-dongml2@chinatelecom.cn
Signed-off-by: Paolo Abeni <pabeni@redhat.com>