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tcp: add LINUX_MIB_PAWS_TW_REJECTED counter

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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: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250409112614.16153-3-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jiayuan Chen
2025-04-10 18:29:26 -07:00
committed by Jakub Kicinski
parent 0427141112
commit c449d5f3a3
5 changed files with 6 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Documentation/networking/net_cachelines/snmp.rst
+2
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@@ -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
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@@ -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
View File
@@ -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
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@@ -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
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@@ -248,7 +248,7 @@ kill:
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) {