Subject: [PATCH net-next v3] net-timestamp: namespacify the sysctl_tstamp_allow_data

From: Jason Xing <[email-masked]>
Date: Thu, 3 Oct 2024 19:40:35 +0900

From: Jason Xing <[email-masked]>

Let it be tuned in per netns by admins.

Signed-off-by: Jason Xing <[email-masked]>
---
v3
Link: https://lore.kernel.org/all/CANn89iLVRPHQ0TzWWOs8S1hA5Uwck_j=[email-masked]/
1. move sysctl_tstamp_allow_data after sysctl_txrehash (Eric)

v2
Link: https://lore.kernel.org/all/[email-masked]/
1. remove the static global from sock.c
2. reorder the tests
3. I removed the patch [1/3] because I made one mistake
4. I also removed the patch [2/3] because Willem soon will propose a
packetdrill test that is better.
Now, I only need to write this standalone patch.
---
 include/net/netns/core.h   |  1 +
 include/net/sock.h         |  2 --
 net/core/net_namespace.c   |  1 +
 net/core/skbuff.c          |  2 +-
 net/core/sock.c            |  2 --
 net/core/sysctl_net_core.c | 18 +++++++++---------
 6 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/include/net/netns/core.h b/include/net/netns/core.h
index 78214f1b43a2..7a4f9588b1b2 100644
--- a/include/net/netns/core.h
+++ b/include/net/netns/core.h
@@ -15,6 +15,7 @@ struct netns_core {
 	int	sysctl_somaxconn;
 	int	sysctl_optmem_max;
 	u8	sysctl_txrehash;
+	int	sysctl_tstamp_allow_data;
 
 #ifdef CONFIG_PROC_FS
 	struct prot_inuse __percpu *prot_inuse;
diff --git a/include/net/sock.h b/include/net/sock.h
index c58ca8dd561b..4f31be0fd671 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2808,8 +2808,6 @@ void sk_get_meminfo(const struct sock *sk, u32 *meminfo);
 extern __u32 sysctl_wmem_max;
 extern __u32 sysctl_rmem_max;
 
-extern int sysctl_tstamp_allow_data;
-
 extern __u32 sysctl_wmem_default;
 extern __u32 sysctl_rmem_default;
 
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index e39479f1c9a4..e78c01912c64 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -317,6 +317,7 @@ static __net_init void preinit_net_sysctl(struct net *net)
 	 */
 	net->core.sysctl_optmem_max = 128 * 1024;
 	net->core.sysctl_txrehash = SOCK_TXREHASH_ENABLED;
+	net->core.sysctl_tstamp_allow_data = 1;
 }
 
 /* init code that must occur even if setup_net() is not called. */
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 74149dc4ee31..00afeb90c23a 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5506,7 +5506,7 @@ static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly)
 {
 	bool ret;
 
-	if (likely(READ_ONCE(sysctl_tstamp_allow_data) || tsonly))
+	if (likely(tsonly || READ_ONCE(sock_net(sk)->core.sysctl_tstamp_allow_data)))
 		return true;
 
 	read_lock_bh(&sk->sk_callback_lock);
diff --git a/net/core/sock.c b/net/core/sock.c
index fe87f9bd8f16..93b6c1d0317d 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -286,8 +286,6 @@ EXPORT_SYMBOL(sysctl_rmem_max);
 __u32 sysctl_wmem_default __read_mostly = SK_WMEM_MAX;
 __u32 sysctl_rmem_default __read_mostly = SK_RMEM_MAX;
 
-int sysctl_tstamp_allow_data __read_mostly = 1;
-
 DEFINE_STATIC_KEY_FALSE(memalloc_socks_key);
 EXPORT_SYMBOL_GPL(memalloc_socks_key);
 
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 86a2476678c4..83622799eb80 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -491,15 +491,6 @@ static struct ctl_table net_core_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{
-		.procname	= "tstamp_allow_data",
-		.data		= &sysctl_tstamp_allow_data,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE
-	},
 #ifdef CONFIG_RPS
 	{
 		.procname	= "rps_sock_flow_entries",
@@ -665,6 +656,15 @@ static struct ctl_table netns_core_table[] = {
 		.extra2		= SYSCTL_ONE,
 		.proc_handler	= proc_dou8vec_minmax,
 	},
+	{
+		.procname	= "tstamp_allow_data",
+		.data		= &init_net.core.sysctl_tstamp_allow_data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE
+	},
 	/* sysctl_core_net_init() will set the values after this
 	 * to readonly in network namespaces
 	 */
-- 
2.37.3