Commit d16b3447 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

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: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarNeal Cardwell <ncardwell@google.com>
Reviewed-by: default avatarJason Xing <kerneljasonxing@gmail.com>
Tested-by: default avatarNeal Cardwell <ncardwell@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250113135558.3180360-4-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 124c4c32

include/net/dropreason-core.h

+1 −0
Original line number Diff line number Diff line
@@ -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) */

include/uapi/linux/snmp.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */

net/ipv4/proc.c

+1 −0
Original line number Diff line number Diff line
@@ -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),

net/ipv4/tcp_input.c

+4 −3
Original line number Diff line number Diff line
@@ -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,