sctp: add probe_interval in sysctl and sock/asoc/transport

PLPMTUD can be enabled by doing 'sysctl -w net.sctp.probe_interval=n'.
'n' is the interval for PLPMTUD probe timer in milliseconds, and it
can't be less than 5000 if it's not 0.

All asoc/transport's PLPMTUD in a new socket will be enabled by default.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 35 insertions, 0 deletions

diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 55871b277f47..b46a416787ec 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -55,6 +55,8 @@ static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
 				   void *buffer, size_t *lenp, loff_t *ppos);
 static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
 			     void *buffer, size_t *lenp, loff_t *ppos);
+static int proc_sctp_do_probe_interval(struct ctl_table *ctl, int write,
+				       void *buffer, size_t *lenp, loff_t *ppos);
 
 static struct ctl_table sctp_table[] = {
 	{
@@ -294,6 +296,13 @@ static struct ctl_table sctp_net_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 	{
+		.procname	= "plpmtud_probe_interval",
+		.data		= &init_net.sctp.probe_interval,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_sctp_do_probe_interval,
+	},
+	{
 		.procname	= "udp_port",
 		.data		= &init_net.sctp.udp_port,
 		.maxlen		= sizeof(int),
@@ -539,6 +548,32 @@ static int proc_sctp_do_udp_port(struct ctl_table *ctl, int write,
 	return ret;
 }
 
+static int proc_sctp_do_probe_interval(struct ctl_table *ctl, int write,
+				       void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct net *net = current->nsproxy->net_ns;
+	struct ctl_table tbl;
+	int ret, new_value;
+
+	memset(&tbl, 0, sizeof(struct ctl_table));
+	tbl.maxlen = sizeof(unsigned int);
+
+	if (write)
+		tbl.data = &new_value;
+	else
+		tbl.data = &net->sctp.probe_interval;
+
+	ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
+	if (write && ret == 0) {
+		if (new_value && new_value < SCTP_PROBE_TIMER_MIN)
+			return -EINVAL;
+
+		net->sctp.probe_interval = new_value;
+	}
+
+	return ret;
+}
+
 int sctp_sysctl_net_register(struct net *net)
 {
 	struct ctl_table *table;