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From: "Maciej Żenczykowski" <maze@google•com>
To: "Maciej Żenczykowski" <zenczykowski@gmail•com>,
	"Pablo Neira Ayuso" <pablo@netfilter•org>,
	"Florian Westphal" <fw@strlen•de>
Cc: "Linux Network Development Mailing List" <netdev@vger•kernel.org>,
	"Netfilter Development Mailing List"
	<netfilter-devel@vger•kernel.org>,
	"Maciej Żenczykowski" <maze@google•com>,
	"Martin KaFai Lau" <kafai@fb•com>
Subject: [PATCH netfilter] netfilter: nfnetlink_log: always add a timestamp
Date: Tue, 25 Jul 2023 01:54:43 -0700	[thread overview]
Message-ID: <20230725085443.2102634-1-maze@google.com> (raw)

Compared to all the other work we're already doing to deliver
an skb to userspace this is very cheap - at worse an extra
call to ktime_get_real() - and very useful.

(and indeed it may even be cheaper if we're running from other hooks)

(background: Android occasionally logs packets which
caused wake from sleep/suspend and we'd like to have
timestamps reliably associated with these events)

Cc: Pablo Neira Ayuso <pablo@netfilter•org>
Cc: Martin KaFai Lau <kafai@fb•com>
Cc: Florian Westphal <fw@strlen•de>
Signed-off-by: Maciej Żenczykowski <maze@google•com>
---
 net/netfilter/nfnetlink_log.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index e57eb168ee13..53c9e76473ba 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -470,7 +470,6 @@ __build_packet_message(struct nfnl_log_net *log,
 	sk_buff_data_t old_tail = inst->skb->tail;
 	struct sock *sk;
 	const unsigned char *hwhdrp;
-	ktime_t tstamp;
 
 	nlh = nfnl_msg_put(inst->skb, 0, 0,
 			   nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET),
@@ -599,10 +598,9 @@ __build_packet_message(struct nfnl_log_net *log,
 			goto nla_put_failure;
 	}
 
-	tstamp = skb_tstamp_cond(skb, false);
-	if (hooknum <= NF_INET_FORWARD && tstamp) {
+	if (hooknum <= NF_INET_FORWARD) {
+		struct timespec64 kts = ktime_to_timespec64(skb_tstamp_cond(skb, true));
 		struct nfulnl_msg_packet_timestamp ts;
-		struct timespec64 kts = ktime_to_timespec64(tstamp);
 		ts.sec = cpu_to_be64(kts.tv_sec);
 		ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);
 
-- 
2.41.0.487.g6d72f3e995-goog


             reply	other threads:[~2023-07-25  8:55 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-25  8:54 Maciej Żenczykowski [this message]
2023-07-27 13:58 ` [PATCH netfilter] netfilter: nfnetlink_log: always add a timestamp Florian Westphal
2023-08-04 19:26   ` Maciej Żenczykowski
2023-08-04 19:40     ` Florian Westphal

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