xref: /kernel/linux/linux-5.10/net/mptcp/ctrl.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0
2/* Multipath TCP
3 *
4 * Copyright (c) 2019, Tessares SA.
5 */
6
7#include <linux/sysctl.h>
8
9#include <net/net_namespace.h>
10#include <net/netns/generic.h>
11
12#include "protocol.h"
13
14#define MPTCP_SYSCTL_PATH "net/mptcp"
15
16static int mptcp_pernet_id;
17struct mptcp_pernet {
18	struct ctl_table_header *ctl_table_hdr;
19
20	int mptcp_enabled;
21};
22
23static struct mptcp_pernet *mptcp_get_pernet(struct net *net)
24{
25	return net_generic(net, mptcp_pernet_id);
26}
27
28int mptcp_is_enabled(struct net *net)
29{
30	return mptcp_get_pernet(net)->mptcp_enabled;
31}
32
33static struct ctl_table mptcp_sysctl_table[] = {
34	{
35		.procname = "enabled",
36		.maxlen = sizeof(int),
37		.mode = 0644,
38		/* users with CAP_NET_ADMIN or root (not and) can change this
39		 * value, same as other sysctl or the 'net' tree.
40		 */
41		.proc_handler = proc_dointvec,
42	},
43	{}
44};
45
46static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
47{
48	pernet->mptcp_enabled = 1;
49}
50
51static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet)
52{
53	struct ctl_table_header *hdr;
54	struct ctl_table *table;
55
56	table = mptcp_sysctl_table;
57	if (!net_eq(net, &init_net)) {
58		table = kmemdup(table, sizeof(mptcp_sysctl_table), GFP_KERNEL);
59		if (!table)
60			goto err_alloc;
61	}
62
63	table[0].data = &pernet->mptcp_enabled;
64
65	hdr = register_net_sysctl(net, MPTCP_SYSCTL_PATH, table);
66	if (!hdr)
67		goto err_reg;
68
69	pernet->ctl_table_hdr = hdr;
70
71	return 0;
72
73err_reg:
74	if (!net_eq(net, &init_net))
75		kfree(table);
76err_alloc:
77	return -ENOMEM;
78}
79
80static void mptcp_pernet_del_table(struct mptcp_pernet *pernet)
81{
82	struct ctl_table *table = pernet->ctl_table_hdr->ctl_table_arg;
83
84	unregister_net_sysctl_table(pernet->ctl_table_hdr);
85
86	kfree(table);
87}
88
89static int __net_init mptcp_net_init(struct net *net)
90{
91	struct mptcp_pernet *pernet = mptcp_get_pernet(net);
92
93	mptcp_pernet_set_defaults(pernet);
94
95	return mptcp_pernet_new_table(net, pernet);
96}
97
98/* Note: the callback will only be called per extra netns */
99static void __net_exit mptcp_net_exit(struct net *net)
100{
101	struct mptcp_pernet *pernet = mptcp_get_pernet(net);
102
103	mptcp_pernet_del_table(pernet);
104}
105
106static struct pernet_operations mptcp_pernet_ops = {
107	.init = mptcp_net_init,
108	.exit = mptcp_net_exit,
109	.id = &mptcp_pernet_id,
110	.size = sizeof(struct mptcp_pernet),
111};
112
113void __init mptcp_init(void)
114{
115	mptcp_join_cookie_init();
116	mptcp_proto_init();
117
118	if (register_pernet_subsys(&mptcp_pernet_ops) < 0)
119		panic("Failed to register MPTCP pernet subsystem.\n");
120}
121
122#if IS_ENABLED(CONFIG_MPTCP_IPV6)
123int __init mptcpv6_init(void)
124{
125	int err;
126
127	err = mptcp_proto_v6_init();
128
129	return err;
130}
131#endif
132