[PATCH net-next 1/3] tcp: add TCP_RTO_MAX_MIN_SEC definition

[Jason Xing <kerneljasonxing@gmail.com>]

Add minimum value definition as the lower bound of RTO MAX
set by users. In the next patch, bpf_sol_tcp_setsockopt()
will use this in the test statement.

Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
---
 include/net/tcp.h          | 1 +
 net/ipv4/sysctl_net_ipv4.c | 3 ++-
 net/ipv4/tcp.c             | 3 ++-
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 7fd2d7fa4532..b6bedbe68636 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -143,6 +143,7 @@ static_assert((1 << ATO_BITS) > TCP_DELACK_MAX);
 #define TCP_DELACK_MIN	4U
 #define TCP_ATO_MIN	4U
 #endif
+#define TCP_RTO_MAX_MIN_SEC 1
 #define TCP_RTO_MAX_SEC 120
 #define TCP_RTO_MAX	((unsigned)(TCP_RTO_MAX_SEC * HZ))
 #define TCP_RTO_MIN	((unsigned)(HZ / 5))
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 3a43010d726f..53942c225e0b 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -28,6 +28,7 @@ static int tcp_adv_win_scale_max = 31;
 static int tcp_app_win_max = 31;
 static int tcp_min_snd_mss_min = TCP_MIN_SND_MSS;
 static int tcp_min_snd_mss_max = 65535;
+static int tcp_rto_max_min = TCP_RTO_MAX_MIN_SEC * MSEC_PER_SEC;
 static int tcp_rto_max_max = TCP_RTO_MAX_SEC * MSEC_PER_SEC;
 static int ip_privileged_port_min;
 static int ip_privileged_port_max = 65535;
@@ -1590,7 +1591,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ONE_THOUSAND,
+		.extra1		= &tcp_rto_max_min,
 		.extra2		= &tcp_rto_max_max,
 	},
 };
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 992d5c9b2487..2373ab1a1d47 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3812,7 +3812,8 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname,
 					   TCP_RTO_MAX / HZ));
 		return 0;
 	case TCP_RTO_MAX_MS:
-		if (val < MSEC_PER_SEC || val > TCP_RTO_MAX_SEC * MSEC_PER_SEC)
+		if (val < TCP_RTO_MAX_MIN_SEC * MSEC_PER_SEC ||
+		    val > TCP_RTO_MAX_SEC * MSEC_PER_SEC)
 			return -EINVAL;
 		WRITE_ONCE(inet_csk(sk)->icsk_rto_max, msecs_to_jiffies(val));
 		return 0;
-- 
2.43.5