Commit c449d5f3 authored by Jiayuan Chen's avatar Jiayuan Chen Committed by Jakub Kicinski
Browse files

tcp: add LINUX_MIB_PAWS_TW_REJECTED counter 



When TCP is in TIME_WAIT state, PAWS verification uses
LINUX_PAWSESTABREJECTED, which is ambiguous and cannot be distinguished
from other PAWS verification processes.

We added a new counter, like the existing PAWS_OLD_ACK one.

Also we update the doc with previously missing PAWS_OLD_ACK.

usage:
'''
nstat -az | grep PAWSTimewait
TcpExtPAWSTimewait              1                  0.0
'''

Suggested-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarJiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250409112614.16153-3-jiayuan.chen@linux.dev


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 04271411

Documentation/networking/net_cachelines/snmp.rst

+2 −0
Original line number Diff line number Diff line
@@ -37,6 +37,8 @@ unsigned_long LINUX_MIB_TIMEWAITKILLED 
unsigned_long  LINUX_MIB_PAWSACTIVEREJECTED

unsigned_long  LINUX_MIB_PAWSESTABREJECTED

unsigned_long  LINUX_MIB_TSECR_REJECTED

unsigned_long  LINUX_MIB_PAWS_OLD_ACK

unsigned_long  LINUX_MIB_PAWS_TW_REJECTED

unsigned_long  LINUX_MIB_DELAYEDACKLOST

unsigned_long  LINUX_MIB_LISTENOVERFLOWS

unsigned_long  LINUX_MIB_LISTENDROPS

include/net/dropreason-core.h

+1 −0
Original line number Diff line number Diff line
@@ -287,6 +287,7 @@ enum skb_drop_reason { 
	/**

	 * @SKB_DROP_REASON_TCP_RFC7323_TW_PAWS: PAWS check, socket is in

	 * TIME_WAIT state.

	 * Corresponds to LINUX_MIB_PAWS_TW_REJECTED.

	 */

	SKB_DROP_REASON_TCP_RFC7323_TW_PAWS,

	/**

include/uapi/linux/snmp.h

+1 −0
Original line number Diff line number Diff line
@@ -188,6 +188,7 @@ enum 
	LINUX_MIB_PAWSESTABREJECTED,		/* PAWSEstabRejected */

	LINUX_MIB_TSECRREJECTED,		/* TSEcrRejected */

	LINUX_MIB_PAWS_OLD_ACK,			/* PAWSOldAck */

	LINUX_MIB_PAWS_TW_REJECTED,		/* PAWSTimewait */

	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
@@ -191,6 +191,7 @@ static const struct snmp_mib snmp4_net_list[] = { 
	SNMP_MIB_ITEM("PAWSEstab", LINUX_MIB_PAWSESTABREJECTED),

	SNMP_MIB_ITEM("TSEcrRejected", LINUX_MIB_TSECRREJECTED),

	SNMP_MIB_ITEM("PAWSOldAck", LINUX_MIB_PAWS_OLD_ACK),

	SNMP_MIB_ITEM("PAWSTimewait", LINUX_MIB_PAWS_TW_REJECTED),

	SNMP_MIB_ITEM("DelayedACKs", LINUX_MIB_DELAYEDACKS),

	SNMP_MIB_ITEM("DelayedACKLocked", LINUX_MIB_DELAYEDACKLOCKED),

	SNMP_MIB_ITEM("DelayedACKLost", LINUX_MIB_DELAYEDACKLOST),

net/ipv4/tcp_minisocks.c

+1 −1
Original line number Diff line number Diff line
@@ -248,7 +248,7 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, 


	if (paws_reject) {

		*drop_reason = SKB_DROP_REASON_TCP_RFC7323_TW_PAWS;

		__NET_INC_STATS(twsk_net(tw), LINUX_MIB_PAWSESTABREJECTED);

		__NET_INC_STATS(twsk_net(tw), LINUX_MIB_PAWS_TW_REJECTED);

	}



	if (!th->rst) {