Merge branch 'tcp-rcv-drop-reasons'

Jason Xing says:

====================
introduce drop reasons for tcp receive path

When I was debugging the reason about why the skb should be dropped in
syn cookie mode, I found out that this NOT_SPECIFIED reason is too
general. Thus I decided to refine it.

v10
Link: https://lore.kernel.org/netdev/20240223193321.6549-1-kuniyu@amazon.com/
1. fix three nit problems (Kuniyuki)
2. add reviewed-by tag (Kuniyuki)

v9
Link: https://lore.kernel.org/netdev/20240222113003.67558-1-kerneljasonxing@gmail.com/
1. nit: remove one unneeded 'else' (David)
2. add reviewed-by tags (Eric, David)

v8
Link: https://lore.kernel.org/netdev/20240221025732.68157-1-kerneljasonxing@gmail.com/
1. refine part of codes in patch [03/10] and patch [10/10] (Eric)
2. squash patch [11/11] in the last version into patch [10/11] (Eric)
3. add reviewed-by tags (Eric)

v7
Link: https://lore.kernel.org/all/20240219032838.91723-1-kerneljasonxing@gmail.com/
1. fix some misspelled problem (Kuniyuki)
2. remove redundant codes in tcp_v6_do_rcv() (Kuniyuki)
3. add reviewed-by tag in patch [02/11] (Kuniyuki)

v6
Link: https://lore.kernel.org/all/c987d2c79e4a4655166eb8eafef473384edb37fb.camel@redhat.com/
Link: https://lore.kernel.org/all/CAL+tcoAgSjwsmFnDh_Gs9ZgMi-y5awtVx+4VhJPNRADjo7LLSA@mail.gmail.com/
1. Take one case into consideration in tcp_v6_do_rcv(), behave like old
days, or else it will trigger errors (Paolo).
2. Extend NO_SOCKET reason to consider two more reasons for request
socket and child socket.

v5:
Link: https://lore.kernel.org/netdev/20240213134205.8705-1-kerneljasonxing@gmail.com/
Link: https://lore.kernel.org/netdev/20240213140508.10878-1-kerneljasonxing@gmail.com/
1. Use SKB_DROP_REASON_IP_OUTNOROUTES instead of introducing a new
   one (Eric, David)
2. Reuse SKB_DROP_REASON_NOMEM to handle failure of request socket
   allocation (Eric)
3. Reuse NO_SOCKET instead of introducing COOKIE_NOCHILD
4. avoid duplication of these opt_skb tests/actions (Eric)
5. Use new name (TCP_ABORT_ON_DATA) for readability (David)
6. Reuse IP_OUTNOROUTES instead of INVALID_DST (Eric)

---
HISTORY
This series is combined with 2 series sent before suggested by Jakub. So
I'm going to separately write changelogs for each of them.

PATCH 1/11 - 5/11
Link: https://lore.kernel.org/netdev/20240213134205.8705-1-kerneljasonxing@gmail.com/
Summary
1. introduce all the dropreasons we need, [1/11] patch.
2. use new dropreasons in ipv4 cookie check, [2/11],[3/11] patch.
3. use new dropreasons ipv6 cookie check, [4/11],[5/11] patch.

v4:
Link: https://lore.kernel.org/netdev/20240212172302.3f95e454@kernel.org/
1. Fix misspelled name in Kdoc as suggested by Jakub.

v3:
Link: https://lore.kernel.org/all/CANn89iK40SoyJ8fS2U5kp3pDruo=zfQNPL-ppOF+LYaS9z-MVA@mail.gmail.com/
1. Split that patch into some smaller ones as suggested by Eric.

v2:
Link: https://lore.kernel.org/all/20240204104601.55760-1-kerneljasonxing@gmail.com/
1. change the title of 2/2 patch.
2. fix some warnings checkpatch tool showed before.
3. use return value instead of adding more parameters suggested by Eric.

PATCH 6/11 - 11/11
Link: https://lore.kernel.org/netdev/20240213140508.10878-1-kerneljasonxing@gmail.com/
v4:
Link: https://lore.kernel.org/netdev/CANn89iJar+H3XkQ8HpsirH7b-_sbFe9NBUdAAO3pNJK3CKr_bg@mail.gmail.com/
Link: https://lore.kernel.org/netdev/20240213131205.4309-1-kerneljasonxing@gmail.com/
Already got rid of @acceptable in tcp_rcv_state_process(), so I need to
remove *TCP_CONNREQNOTACCEPTABLE related codes which I wrote in the v3
series.

v3:
Link: https://lore.kernel.org/all/CANn89iK40SoyJ8fS2U5kp3pDruo=zfQNPL-ppOF+LYaS9z-MVA@mail.gmail.com/
1. Split that patch into some smaller ones as suggested by Eric.

v2:
Link: https://lore.kernel.org/all/20240204104601.55760-1-kerneljasonxing@gmail.com/
1. change the title of 2/2 patch.
2. fix some warnings checkpatch tool showed before.
3. use return value instead of adding more parameters suggested by Eric.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>