From patchwork Tue Mar 25 14:47:03 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiayuan Chen X-Patchwork-Id: 14029115 X-Patchwork-Delegate: kuba@kernel.org Received: from out-180.mta0.migadu.com (out-180.mta0.migadu.com [91.218.175.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B955B25B66D for ; Tue, 25 Mar 2025 14:47:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.180 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742914057; cv=none; b=EqU9HhXZcBJSyocfq3FJo8jUnUT2Jn4tnv4liKRJ/ORCoPOdL11UUl66wFbncROoWZHTaGmTxkO/RPdSg/uS0petv1mFA10nUA8baDWgoeDRcJLQNCPIxjlEyDnX7Rlrf4dCcSxp9ZYSdFVHAwsJaU7NbZPrgq4/moV/y5ueySs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742914057; c=relaxed/simple; bh=q2qQFTSe1OkKnGQNlpYQcfnrah8hpzXx6xnjth4cRDA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Hm8JwYEWWEV9JDxeu23VmlDfV3/SWLZMd3hgM+X7p1SfI5t8nt+BHt2J7IZH0wfRQa+YCL57UwnYtmsgV2jLzVJos389OGASjavgb3+h/tC1CJT+ISdO60XSmlkNX1OJ3gV+0nkGy6z+zfu8Qj4/rcUxKHDAMv/VzuY0PhzeX+8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=JPF+1mNW; arc=none smtp.client-ip=91.218.175.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="JPF+1mNW" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1742914053; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8X1RuBZ4xu4ElYT522Edj/zRVuiFXsGcUeYWcjQGzGM=; b=JPF+1mNWCqPcEyhjDXB7X+aiB80HyW5KziMavpA/fKA8r01fyRGoU3rES9UgCzSmy61KRx DCYF6obLrpX6yGHC4m3qP8NL1xAjVMZfVA9+Xl7qk1+hATLKsq/GdCUy5kIx56PKzUM0HM l1Ovu94RTt9C++6IfYUx5+wzyJYidX4= From: Jiayuan Chen To: netdev@vger.kernel.org, edumazet@google.com Cc: linux-kernel@vger.kernel.org, kuniyu@amazon.com, davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, dsahern@kernel.org, ncardwell@google.com, mrpre@163.com, Jiayuan Chen Subject: [PATCH net-next v3 1/2] tcp: add TCP_RFC7323_TW_PAWS drop reason Date: Tue, 25 Mar 2025 22:47:03 +0800 Message-ID: <20250325144704.14363-2-jiayuan.chen@linux.dev> In-Reply-To: <20250325144704.14363-1-jiayuan.chen@linux.dev> References: <20250325144704.14363-1-jiayuan.chen@linux.dev> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Patchwork-Delegate: kuba@kernel.org PAWS is a long-standing issue, especially when there are upstream network devices, making it more prone to occur. Currently, packet loss statistics for PAWS can only be viewed through MIB, which is a global metric and cannot be precisely obtained through tracing to get the specific 4-tuple of the dropped packet. In the past, we had to use kprobe ret to retrieve relevant skb information from tcp_timewait_state_process(). We add a drop_reason pointer, similar to what previous commit does: commit e34100c2ecbb ("tcp: add a drop_reason pointer to tcp_check_req()") This commit addresses the PAWSESTABREJECTED case and also sets the corresponding drop reason. We use 'pwru' to test. Before this commit: '''' ./pwru 'port 9999' 2025/03/25 22:00:03 Listening for events.. TUPLE FUNC 172.31.75.115:12345->172.31.75.114:9999(tcp) sk_skb_reason_drop(SKB_DROP_REASON_NOT_SPECIFIED) ''' After this commit: ''' ./pwru 'port 9999' 2025/03/25 22:21:46 Listening for events.. TUPLE FUNC 172.31.75.115:12345->172.31.75.114:9999(tcp) sk_skb_reason_drop(SKB_DROP_REASON_TCP_RFC7323_TW_PAWS) ''' Suggested-by: Eric Dumazet Signed-off-by: Jiayuan Chen --- include/net/dropreason-core.h | 6 ++++++ include/net/tcp.h | 3 ++- net/ipv4/tcp_ipv4.c | 3 ++- net/ipv4/tcp_minisocks.c | 7 +++++-- net/ipv6/tcp_ipv6.c | 3 ++- 5 files changed, 17 insertions(+), 5 deletions(-) diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h index e4fdc6b54cef..9701d7f936f6 100644 --- a/include/net/dropreason-core.h +++ b/include/net/dropreason-core.h @@ -40,6 +40,7 @@ FN(TCP_OFOMERGE) \ FN(TCP_RFC7323_PAWS) \ FN(TCP_RFC7323_PAWS_ACK) \ + FN(TCP_RFC7323_TW_PAWS) \ FN(TCP_RFC7323_TSECR) \ FN(TCP_LISTEN_OVERFLOW) \ FN(TCP_OLD_SEQUENCE) \ @@ -283,6 +284,11 @@ enum skb_drop_reason { * Corresponds to LINUX_MIB_PAWS_OLD_ACK. */ SKB_DROP_REASON_TCP_RFC7323_PAWS_ACK, + /** + * @SKB_DROP_REASON_TCP_RFC7323_TW_PAWS: PAWS check, socket is in + * TIME_WAIT state. + */ + SKB_DROP_REASON_TCP_RFC7323_TW_PAWS, /** * @SKB_DROP_REASON_TCP_RFC7323_TSECR: PAWS check, invalid TSEcr. * Corresponds to LINUX_MIB_TSECRREJECTED. diff --git a/include/net/tcp.h b/include/net/tcp.h index f8efe56bbccb..e1574e804530 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -427,7 +427,8 @@ enum tcp_tw_status { enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, const struct tcphdr *th, - u32 *tw_isn); + u32 *tw_isn, + enum skb_drop_reason *drop_reason); struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, struct request_sock *req, bool fastopen, bool *lost_race, enum skb_drop_reason *drop_reason); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 1cd0938d47e0..396141151530 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2417,7 +2417,8 @@ int tcp_v4_rcv(struct sk_buff *skb) goto csum_error; } - tw_status = tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn); + tw_status = tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn, + &drop_reason); switch (tw_status) { case TCP_TW_SYN: { struct sock *sk2 = inet_lookup_listener(net, diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index fb9349be36b8..27511bf58c0f 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -97,7 +97,8 @@ static void twsk_rcv_nxt_update(struct tcp_timewait_sock *tcptw, u32 seq, */ enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, - const struct tcphdr *th, u32 *tw_isn) + const struct tcphdr *th, u32 *tw_isn, + enum skb_drop_reason *drop_reason) { struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw); u32 rcv_nxt = READ_ONCE(tcptw->tw_rcv_nxt); @@ -245,8 +246,10 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, return TCP_TW_SYN; } - if (paws_reject) + if (paws_reject) { + *drop_reason = SKB_DROP_REASON_TCP_RFC7323_TW_PAWS; __NET_INC_STATS(twsk_net(tw), LINUX_MIB_PAWSESTABREJECTED); + } if (!th->rst) { /* In this case we must reset the TIMEWAIT timer. diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index c134cf1a603a..e1afb17cf101 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1970,7 +1970,8 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) goto csum_error; } - tw_status = tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn); + tw_status = tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn, + &drop_reason); switch (tw_status) { case TCP_TW_SYN: { From patchwork Tue Mar 25 14:47:04 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiayuan Chen X-Patchwork-Id: 14029117 X-Patchwork-Delegate: kuba@kernel.org Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2107725A640 for ; 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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1742914062; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8xwJEyFiNpZJx3SaGRoYy6EGc/eXAk39jTVoaj7Yj4Y=; b=M0GQ80LDJ/lC/A+AKKrvato8INN3kffgFKiNBRLjChpIIGsxc7DiHprLhehJ9EqGT09p0r YLB21lNJ+5YNljlYUWPCVbklaEtJ99QzTa/83GKAOWDov5fpwRaecIRPZFu71YMTJ9VtFy PH/TIitAGXu1VoNfAMRTRi1BplbRJOc= From: Jiayuan Chen To: netdev@vger.kernel.org, edumazet@google.com Cc: linux-kernel@vger.kernel.org, kuniyu@amazon.com, davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, dsahern@kernel.org, ncardwell@google.com, mrpre@163.com, Jiayuan Chen Subject: [PATCH net-next v3 2/2] tcp: add LINUX_MIB_PAWS_TW_REJECTED counter Date: Tue, 25 Mar 2025 22:47:04 +0800 Message-ID: <20250325144704.14363-3-jiayuan.chen@linux.dev> In-Reply-To: <20250325144704.14363-1-jiayuan.chen@linux.dev> References: <20250325144704.14363-1-jiayuan.chen@linux.dev> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Patchwork-Delegate: kuba@kernel.org When TCP is in TIME_WAIT state, PAWS verification uses LINUX_PAWSESTABREJECTED, which is ambiguous and cannot be distinguished from other PAWS verification processes. Moreover, when PAWS occurs in TIME_WAIT, we typically need to pay special attention to upstream network devices, so 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 Signed-off-by: Jiayuan Chen --- Documentation/networking/net_cachelines/snmp.rst | 2 ++ include/net/dropreason-core.h | 1 + include/uapi/linux/snmp.h | 1 + net/ipv4/proc.c | 1 + net/ipv4/tcp_minisocks.c | 2 +- 5 files changed, 6 insertions(+), 1 deletion(-) diff --git a/Documentation/networking/net_cachelines/snmp.rst b/Documentation/networking/net_cachelines/snmp.rst index bc96efc92cf5..bd44b3eebbef 100644 --- a/Documentation/networking/net_cachelines/snmp.rst +++ b/Documentation/networking/net_cachelines/snmp.rst @@ -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 diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h index 9701d7f936f6..bea77934a235 100644 --- a/include/net/dropreason-core.h +++ b/include/net/dropreason-core.h @@ -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, /** diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index eb9fb776fdc3..cca7f7eb6e9c 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -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 */ diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 10cbeb76c274..ea2f01584379 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -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), diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 27511bf58c0f..43d7852ce07e 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -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) {