1 /*
2  * (C) 2010 Pablo Neira Ayuso <pablo@netfilter.org>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation (or any later at your option).
7  */
8 
9 #include <linux/netfilter.h>
10 #include <linux/slab.h>
11 #include <linux/kernel.h>
12 #include <linux/moduleparam.h>
13 
14 #include <net/netfilter/nf_conntrack.h>
15 #include <net/netfilter/nf_conntrack_extend.h>
16 #include <net/netfilter/nf_conntrack_timestamp.h>
17 
18 static bool nf_ct_tstamp __read_mostly;
19 
20 module_param_named(tstamp, nf_ct_tstamp, bool, 0644);
21 MODULE_PARM_DESC(tstamp, "Enable connection tracking flow timestamping.");
22 
23 #ifdef CONFIG_SYSCTL
24 static struct ctl_table tstamp_sysctl_table[] = {
25 	{
26 		.procname	= "nf_conntrack_timestamp",
27 		.data		= &init_net.ct.sysctl_tstamp,
28 		.maxlen		= sizeof(unsigned int),
29 		.mode		= 0644,
30 		.proc_handler	= proc_dointvec,
31 	},
32 	{}
33 };
34 #endif /* CONFIG_SYSCTL */
35 
36 static const struct nf_ct_ext_type tstamp_extend = {
37 	.len	= sizeof(struct nf_conn_tstamp),
38 	.align	= __alignof__(struct nf_conn_tstamp),
39 	.id	= NF_CT_EXT_TSTAMP,
40 };
41 
42 #ifdef CONFIG_SYSCTL
43 static int nf_conntrack_tstamp_init_sysctl(struct net *net)
44 {
45 	struct ctl_table *table;
46 
47 	table = kmemdup(tstamp_sysctl_table, sizeof(tstamp_sysctl_table),
48 			GFP_KERNEL);
49 	if (!table)
50 		goto out;
51 
52 	table[0].data = &net->ct.sysctl_tstamp;
53 
54 	/* Don't export sysctls to unprivileged users */
55 	if (net->user_ns != &init_user_ns)
56 		table[0].procname = NULL;
57 
58 	net->ct.tstamp_sysctl_header = register_net_sysctl(net,	"net/netfilter",
59 							   table);
60 	if (!net->ct.tstamp_sysctl_header) {
61 		printk(KERN_ERR "nf_ct_tstamp: can't register to sysctl.\n");
62 		goto out_register;
63 	}
64 	return 0;
65 
66 out_register:
67 	kfree(table);
68 out:
69 	return -ENOMEM;
70 }
71 
72 static void nf_conntrack_tstamp_fini_sysctl(struct net *net)
73 {
74 	struct ctl_table *table;
75 
76 	table = net->ct.tstamp_sysctl_header->ctl_table_arg;
77 	unregister_net_sysctl_table(net->ct.tstamp_sysctl_header);
78 	kfree(table);
79 }
80 #else
81 static int nf_conntrack_tstamp_init_sysctl(struct net *net)
82 {
83 	return 0;
84 }
85 
86 static void nf_conntrack_tstamp_fini_sysctl(struct net *net)
87 {
88 }
89 #endif
90 
91 int nf_conntrack_tstamp_pernet_init(struct net *net)
92 {
93 	net->ct.sysctl_tstamp = nf_ct_tstamp;
94 	return nf_conntrack_tstamp_init_sysctl(net);
95 }
96 
97 void nf_conntrack_tstamp_pernet_fini(struct net *net)
98 {
99 	nf_conntrack_tstamp_fini_sysctl(net);
100 }
101 
102 int nf_conntrack_tstamp_init(void)
103 {
104 	int ret;
105 	ret = nf_ct_extend_register(&tstamp_extend);
106 	if (ret < 0)
107 		pr_err("nf_ct_tstamp: Unable to register extension\n");
108 	return ret;
109 }
110 
111 void nf_conntrack_tstamp_fini(void)
112 {
113 	nf_ct_extend_unregister(&tstamp_extend);
114 }
115