[PATCH v3 1/3] ipv4: Namespaceify route/error_cost knob

[cgel . zte]

From: xu xin <xu.xin16@xxxxxxxxxx>

Different netns has different requirement on the setting of error_cost
sysctl which is used to limit the max frequency of sending
ICMP_DEST_UNREACH packet together with error_burst. To put it simply,
it refers to the minimum time interval between two consecutive
ICMP_DEST_UNREACHABLE packets sent to the same peer when now is
icmp-stable period not the burst case after a long calm time.

Enable error_cost to be configured per network namespace.

Signed-off-by: xu xin (CGEL ZTE) <xu.xin16@xxxxxxxxxx>
Reviewed-by: Yunkai Zhang (CGEL ZTE) <zhang.yunkai@xxxxxxxxxx>
---
 include/net/netns/ipv4.h |  1 +
 net/ipv4/route.c         | 18 ++++++++++--------
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index c7320ef356d9..319395bbad3c 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -85,6 +85,7 @@ struct netns_ipv4 {
 	u32 ip_rt_min_pmtu;
 	int ip_rt_mtu_expires;
 	int ip_rt_min_advmss;
+	int ip_rt_error_cost;
 
 	struct local_ports ip_local_ports;
 
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 795cbe1de912..209539c201c2 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -118,7 +118,6 @@ static int ip_rt_max_size;
 static int ip_rt_redirect_number __read_mostly	= 9;
 static int ip_rt_redirect_load __read_mostly	= HZ / 50;
 static int ip_rt_redirect_silence __read_mostly	= ((HZ / 50) << (9 + 1));
-static int ip_rt_error_cost __read_mostly	= HZ;
 static int ip_rt_error_burst __read_mostly	= 5 * HZ;
 
 static int ip_rt_gc_timeout __read_mostly	= RT_GC_TIMEOUT;
@@ -1000,6 +999,8 @@ static int ip_error(struct sk_buff *skb)
 
 	send = true;
 	if (peer) {
+		int ip_rt_error_cost = READ_ONCE(net->ipv4.ip_rt_error_cost);
+
 		now = jiffies;
 		peer->rate_tokens += now - peer->rate_last;
 		if (peer->rate_tokens > ip_rt_error_burst)
@@ -3535,13 +3536,6 @@ static struct ctl_table ipv4_route_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{
-		.procname	= "error_cost",
-		.data		= &ip_rt_error_cost,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
 	{
 		.procname	= "error_burst",
 		.data		= &ip_rt_error_burst,
@@ -3590,6 +3584,13 @@ static struct ctl_table ipv4_route_netns_table[] = {
 		.mode       = 0644,
 		.proc_handler   = proc_dointvec,
 	},
+	{
+		.procname   = "error_cost",
+		.data       = &init_net.ipv4.ip_rt_error_cost,
+		.maxlen     = sizeof(int),
+		.mode       = 0644,
+		.proc_handler   = proc_dointvec,
+	},
 	{ },
 };
 
@@ -3653,6 +3654,7 @@ static __net_init int netns_ip_rt_init(struct net *net)
 	net->ipv4.ip_rt_min_pmtu = DEFAULT_MIN_PMTU;
 	net->ipv4.ip_rt_mtu_expires = DEFAULT_MTU_EXPIRES;
 	net->ipv4.ip_rt_min_advmss = DEFAULT_MIN_ADVMSS;
+	net->ipv4.ip_rt_error_cost = HZ;
 	return 0;
 }
 
-- 
2.25.1