[net-next,0/2] tcp: add a new PAWS_ACK drop reason

Message

Eric Dumazet Jan. 10, 2025, 2:33 p.m. UTC

Current TCP_RFC7323_PAWS drop reason is too generic and can
cause confusion.

One common source for these drops are ACK packets coming too late.

A prior packet with payload already changed tp->rcv_nxt.

Add TCP_RFC7323_PAWS_ACK new drop reason, and do not
generate a DUPACK for such old ACK.

Eric Dumazet (2):
  tcp: add drop_reason support to tcp_disordered_ack()
  tcp: add TCP_RFC7323_PAWS_ACK drop reason

 include/net/dropreason-core.h |  5 +++
 net/ipv4/tcp_input.c          | 85 +++++++++++++++++++++--------------
 2 files changed, 56 insertions(+), 34 deletions(-)