From d16b34479064fcb8dbb66a72308b5034be819161 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 13 Jan 2025 13:55:58 +0000 Subject: [PATCH] tcp: add LINUX_MIB_PAWS_OLD_ACK SNMP counter Prior patch in the series added TCP_RFC7323_PAWS_ACK drop reason. This patch adds the corresponding SNMP counter, for folks using nstat instead of tracing for TCP diagnostics. nstat -az | grep PAWSOldAck Suggested-by: Neal Cardwell Signed-off-by: Eric Dumazet Reviewed-by: Neal Cardwell Reviewed-by: Jason Xing Tested-by: Neal Cardwell Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250113135558.3180360-4-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/net/dropreason-core.h | 1 + include/uapi/linux/snmp.h | 1 + net/ipv4/proc.c | 1 + net/ipv4/tcp_input.c | 7 ++++--- 4 files changed, 7 insertions(+), 3 deletions(-) diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h index 28555109f9bdf..ed864934e20b1 100644 --- a/include/net/dropreason-core.h +++ b/include/net/dropreason-core.h @@ -262,6 +262,7 @@ enum skb_drop_reason { SKB_DROP_REASON_TCP_RFC7323_PAWS, /** * @SKB_DROP_REASON_TCP_RFC7323_PAWS_ACK: PAWS check, old ACK packet. + * Corresponds to LINUX_MIB_PAWS_OLD_ACK. */ SKB_DROP_REASON_TCP_RFC7323_PAWS_ACK, /** @SKB_DROP_REASON_TCP_OLD_SEQUENCE: Old SEQ field (duplicate packet) */ diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index 2e75674e7d4f8..848c7784e684c 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -186,6 +186,7 @@ enum LINUX_MIB_TIMEWAITKILLED, /* TimeWaitKilled */ LINUX_MIB_PAWSACTIVEREJECTED, /* PAWSActiveRejected */ LINUX_MIB_PAWSESTABREJECTED, /* PAWSEstabRejected */ + LINUX_MIB_PAWS_OLD_ACK, /* PAWSOldAck */ LINUX_MIB_DELAYEDACKS, /* DelayedACKs */ LINUX_MIB_DELAYEDACKLOCKED, /* DelayedACKLocked */ LINUX_MIB_DELAYEDACKLOST, /* DelayedACKLost */ diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 40053a02bae10..affd21a0f5728 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -189,6 +189,7 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TWKilled", LINUX_MIB_TIMEWAITKILLED), SNMP_MIB_ITEM("PAWSActive", LINUX_MIB_PAWSACTIVEREJECTED), SNMP_MIB_ITEM("PAWSEstab", LINUX_MIB_PAWSESTABREJECTED), + SNMP_MIB_ITEM("PAWSOldAck", LINUX_MIB_PAWS_OLD_ACK), SNMP_MIB_ITEM("DelayedACKs", LINUX_MIB_DELAYEDACKS), SNMP_MIB_ITEM("DelayedACKLocked", LINUX_MIB_DELAYEDACKLOCKED), SNMP_MIB_ITEM("DelayedACKLost", LINUX_MIB_DELAYEDACKLOST), diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index dc0e88bcc5352..eb82e01da9110 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5969,12 +5969,13 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, if (unlikely(th->syn)) goto syn_challenge; - /* Old ACK are common, do not change PAWSESTABREJECTED + /* Old ACK are common, increment PAWS_OLD_ACK * and do not send a dupack. */ - if (reason == SKB_DROP_REASON_TCP_RFC7323_PAWS_ACK) + if (reason == SKB_DROP_REASON_TCP_RFC7323_PAWS_ACK) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWS_OLD_ACK); goto discard; - + } NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED); if (!tcp_oow_rate_limited(sock_net(sk), skb, LINUX_MIB_TCPACKSKIPPEDPAWS, -- 2.47.2