Merge branch 'net-gro-add-flush-flush_id-checks-and-fix-wrong-offset-in-udp'

Merge branch 'net-gro-add-flush-flush_id-checks-and-fix-wrong-offset-in-udp'

Richard Gobert says:

====================
net: gro: add flush/flush_id checks and fix wrong offset in udp

This series fixes a bug in the complete phase of UDP in GRO, in which
socket lookup fails due to using network_header when parsing encapsulated
packets. The fix is to add network_offset and inner_network_offset to
napi_gro_cb and use these offsets for socket lookup.

In addition p->flush/flush_id should be checked in all UDP flows. The
same logic from tcp_gro_receive is applied for all flows in
udp_gro_receive_segment. This prevents packets with mismatching network
headers (flush/flush_id turned on) from merging in UDP GRO.

The original series includes a change to vxlan test which adds the local
parameter to prevent similar future bugs. I plan to submit it separately to
net-next.

This series is part of a previously submitted series to net-next:
https://lore.kernel.org/all/20240408141720.98832-1-richardbgobert@gmail.com/

v3 -> v4:
 - Store network offsets, and use them only in udp_gro_complete flows
 - Correct commit hash used in Fixes tag
 - v3:
 https://lore.kernel.org/netdev/20240424163045.123528-1-richardbgobert@gmail.com/

v2 -> v3:
 - Add network_offsets and fix udp bug in a single commit to make backporting easier
 - Write to inner_network_offset in {inet,ipv6}_gro_receive
 - Use network_offsets union in tcp[46]_gro_complete as well
 - v2:
 https://lore.kernel.org/netdev/20240419153542.121087-1-richardbgobert@gmail.com/

v1 -> v2:
 - Use network_offsets instead of p_poff param as suggested by Willem
 - Check flush before postpull, and for all UDP GRO flows
 - v1:
 https://lore.kernel.org/netdev/20240412152120.115067-1-richardbgobert@gmail.com/
====================

Link: https://lore.kernel.org/r/20240430143555.126083-1-richardbgobert@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>