ipv4: Namespaceify tcp syn retries sysctl knob

Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/netns/ipv4.h

@@ -98,6 +98,8 @@ struct netns_ipv4 {
 	int sysctl_tcp_keepalive_probes;
 	int sysctl_tcp_keepalive_intvl;
 
+	int sysctl_tcp_syn_retries;
+
 	struct ping_group_range ping_group_range;
 
 	atomic_t dev_addr_genid;

include/net/tcp.h

@@ -240,7 +240,6 @@ extern int sysctl_tcp_timestamps;
 extern int sysctl_tcp_window_scaling;
 extern int sysctl_tcp_sack;
 extern int sysctl_tcp_fin_timeout;
-extern int sysctl_tcp_syn_retries;
 extern int sysctl_tcp_synack_retries;
 extern int sysctl_tcp_retries1;
 extern int sysctl_tcp_retries2;

net/ipv4/sysctl_net_ipv4.c

@@ -291,15 +291,6 @@ static struct ctl_table ipv4_table[] = {
 		.extra1		= &ip_ttl_min,
 		.extra2		= &ip_ttl_max,
 	},
-	{
-		.procname	= "tcp_syn_retries",
-		.data		= &sysctl_tcp_syn_retries,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &tcp_syn_retries_min,
-		.extra2		= &tcp_syn_retries_max
-	},
 	{
 		.procname	= "tcp_synack_retries",
 		.data		= &sysctl_tcp_synack_retries,
@@ -960,6 +951,15 @@ static struct ctl_table ipv4_net_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_jiffies,
 	},
+	{
+		.procname	= "tcp_syn_retries",
+		.data		= &init_net.ipv4.sysctl_tcp_syn_retries,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &tcp_syn_retries_min,
+		.extra2		= &tcp_syn_retries_max
+	},
 	{ }
 };
 

net/ipv4/tcp.c

@@ -2731,6 +2731,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct tcp_sock *tp = tcp_sk(sk);
+	struct net *net = sock_net(sk);
 	int val, len;
 
 	if (get_user(len, optlen))
@@ -2765,7 +2766,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
 		val = keepalive_probes(tp);
 		break;
 	case TCP_SYNCNT:
-		val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
+		val = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries;
 		break;
 	case TCP_LINGER2:
 		val = tp->linger2;

net/ipv4/tcp_ipv4.c

@@ -2388,6 +2388,8 @@ static int __net_init tcp_sk_init(struct net *net)
 	net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
 	net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
 
+	net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
+
 	return 0;
 fail:
 	tcp_sk_exit(net);

net/ipv4/tcp_timer.c

@@ -22,7 +22,6 @@
 #include <linux/gfp.h>
 #include <net/tcp.h>
 
-int sysctl_tcp_syn_retries __read_mostly = TCP_SYN_RETRIES;
 int sysctl_tcp_synack_retries __read_mostly = TCP_SYNACK_RETRIES;
 int sysctl_tcp_retries1 __read_mostly = TCP_RETR1;
 int sysctl_tcp_retries2 __read_mostly = TCP_RETR2;
@@ -157,6 +156,7 @@ static int tcp_write_timeout(struct sock *sk)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct tcp_sock *tp = tcp_sk(sk);
+	struct net *net = sock_net(sk);
 	int retry_until;
 	bool do_reset, syn_set = false;
 
@@ -169,7 +169,7 @@ static int tcp_write_timeout(struct sock *sk)
 				NET_INC_STATS_BH(sock_net(sk),
 						 LINUX_MIB_TCPFASTOPENACTIVEFAIL);
 		}
-		retry_until = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
+		retry_until = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries;
 		syn_set = true;
 	} else {
 		if (retransmits_timed_out(sk, sysctl_tcp_retries1, 0, 0)) {