From: Paolo Abeni Date: Mon, 21 Jul 2025 17:20:22 +0000 (+0200) Subject: tcp: do not increment BeyondWindow MIB for old seq X-Git-Tag: io_uring-6.17-20250815~128^2~43^2 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=b115c7758802f8d14ba8797e0ba979c47d78f310;p=linux-block.git tcp: do not increment BeyondWindow MIB for old seq The mentioned MIB is currently incremented even when a packet with an old sequence number (i.e. a zero window probe) is received, which is IMHO misleading. Explicitly restrict such MIB increment at the relevant events. Fixes: 6c758062c64d ("tcp: add LINUX_MIB_BEYOND_WINDOW") Acked-by: Eric Dumazet Signed-off-by: Paolo Abeni Link: https://patch.msgid.link/20d147292eb4b13b6535e0ad6f56be64d9c330d3.1753118029.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski --- diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 81b6d3770812..71b76e98371a 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5915,7 +5915,11 @@ step1: if (!th->rst) { if (th->syn) goto syn_challenge; - NET_INC_STATS(sock_net(sk), LINUX_MIB_BEYOND_WINDOW); + + if (reason == SKB_DROP_REASON_TCP_INVALID_SEQUENCE || + reason == SKB_DROP_REASON_TCP_INVALID_END_SEQUENCE) + NET_INC_STATS(sock_net(sk), + LINUX_MIB_BEYOND_WINDOW); if (!tcp_oow_rate_limited(sock_net(sk), skb, LINUX_MIB_TCPACKSKIPPEDSEQ, &tp->last_oow_ack_time))