File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/net/xfrm/xfrm_sysctl.c b/net/xfrm/xfrm_sysctl.c
new file mode 100644
index 0000000..05a6e3d
--- /dev/null
+++ b/net/xfrm/xfrm_sysctl.c
@@ -0,0 +1,86 @@
+#include <linux/sysctl.h>
+#include <linux/slab.h>
+#include <net/net_namespace.h>
+#include <net/xfrm.h>
+
+static void __net_init __xfrm_sysctl_init(struct net *net)
+{
+	net->xfrm.sysctl_aevent_etime = XFRM_AE_ETIME;
+	net->xfrm.sysctl_aevent_rseqth = XFRM_AE_SEQT_SIZE;
+	net->xfrm.sysctl_larval_drop = 1;
+	net->xfrm.sysctl_acq_expires = 30;
+}
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table xfrm_table[] = {
+	{
+		.procname	= "xfrm_aevent_etime",
+		.maxlen		= sizeof(u32),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
+	{
+		.procname	= "xfrm_aevent_rseqth",
+		.maxlen		= sizeof(u32),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
+	{
+		.procname	= "xfrm_larval_drop",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
+	{
+		.procname	= "xfrm_acq_expires",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
+	{}
+};
+
+int __net_init xfrm_sysctl_init(struct net *net)
+{
+	struct ctl_table *table;
+
+	__xfrm_sysctl_init(net);
+
+	table = kmemdup(xfrm_table, sizeof(xfrm_table), GFP_KERNEL);
+	if (!table)
+		goto out_kmemdup;
+	table[0].data = &net->xfrm.sysctl_aevent_etime;
+	table[1].data = &net->xfrm.sysctl_aevent_rseqth;
+	table[2].data = &net->xfrm.sysctl_larval_drop;
+	table[3].data = &net->xfrm.sysctl_acq_expires;
+
+	/* Don't export sysctls to unprivileged users */
+	if (net->user_ns != &init_user_ns)
+		table[0].procname = NULL;
+
+	net->xfrm.sysctl_hdr = register_net_sysctl(net, "net/core", table);
+	if (!net->xfrm.sysctl_hdr)
+		goto out_register;
+	return 0;
+
+out_register:
+	kfree(table);
+out_kmemdup:
+	return -ENOMEM;
+}
+
+void __net_exit xfrm_sysctl_fini(struct net *net)
+{
+	struct ctl_table *table;
+
+	table = net->xfrm.sysctl_hdr->ctl_table_arg;
+	unregister_net_sysctl_table(net->xfrm.sysctl_hdr);
+	kfree(table);
+}
+#else
+int __net_init xfrm_sysctl_init(struct net *net)
+{
+	__xfrm_sysctl_init(net);
+	return 0;
+}
+#endif