1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * tcp_diag.c	Module for monitoring TCP transport protocols sockets.
4 *
5 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 */
7
8#include <linux/module.h>
9#include <linux/net.h>
10#include <linux/sock_diag.h>
11#include <linux/inet_diag.h>
12
13#include <linux/tcp.h>
14
15#include <net/netlink.h>
16#include <net/tcp.h>
17
18static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
19			      void *_info)
20{
21	struct tcp_info *info = _info;
22
23	if (inet_sk_state_load(sk) == TCP_LISTEN) {
24		r->idiag_rqueue = READ_ONCE(sk->sk_ack_backlog);
25		r->idiag_wqueue = READ_ONCE(sk->sk_max_ack_backlog);
26	} else if (sk->sk_type == SOCK_STREAM) {
27		const struct tcp_sock *tp = tcp_sk(sk);
28
29		r->idiag_rqueue = max_t(int, READ_ONCE(tp->rcv_nxt) -
30					     READ_ONCE(tp->copied_seq), 0);
31		r->idiag_wqueue = READ_ONCE(tp->write_seq) - tp->snd_una;
32	}
33	if (info)
34		tcp_get_info(sk, info);
35}
36
37#ifdef CONFIG_TCP_MD5SIG
38static void tcp_diag_md5sig_fill(struct tcp_diag_md5sig *info,
39				 const struct tcp_md5sig_key *key)
40{
41	info->tcpm_family = key->family;
42	info->tcpm_prefixlen = key->prefixlen;
43	info->tcpm_keylen = key->keylen;
44	memcpy(info->tcpm_key, key->key, key->keylen);
45
46	if (key->family == AF_INET)
47		info->tcpm_addr[0] = key->addr.a4.s_addr;
48	#if IS_ENABLED(CONFIG_IPV6)
49	else if (key->family == AF_INET6)
50		memcpy(&info->tcpm_addr, &key->addr.a6,
51		       sizeof(info->tcpm_addr));
52	#endif
53}
54
55static int tcp_diag_put_md5sig(struct sk_buff *skb,
56			       const struct tcp_md5sig_info *md5sig)
57{
58	const struct tcp_md5sig_key *key;
59	struct tcp_diag_md5sig *info;
60	struct nlattr *attr;
61	int md5sig_count = 0;
62
63	hlist_for_each_entry_rcu(key, &md5sig->head, node)
64		md5sig_count++;
65	if (md5sig_count == 0)
66		return 0;
67
68	attr = nla_reserve(skb, INET_DIAG_MD5SIG,
69			   md5sig_count * sizeof(struct tcp_diag_md5sig));
70	if (!attr)
71		return -EMSGSIZE;
72
73	info = nla_data(attr);
74	memset(info, 0, md5sig_count * sizeof(struct tcp_diag_md5sig));
75	hlist_for_each_entry_rcu(key, &md5sig->head, node) {
76		tcp_diag_md5sig_fill(info++, key);
77		if (--md5sig_count == 0)
78			break;
79	}
80
81	return 0;
82}
83#endif
84
85static int tcp_diag_put_ulp(struct sk_buff *skb, struct sock *sk,
86			    const struct tcp_ulp_ops *ulp_ops)
87{
88	struct nlattr *nest;
89	int err;
90
91	nest = nla_nest_start_noflag(skb, INET_DIAG_ULP_INFO);
92	if (!nest)
93		return -EMSGSIZE;
94
95	err = nla_put_string(skb, INET_ULP_INFO_NAME, ulp_ops->name);
96	if (err)
97		goto nla_failure;
98
99	if (ulp_ops->get_info)
100		err = ulp_ops->get_info(sk, skb);
101	if (err)
102		goto nla_failure;
103
104	nla_nest_end(skb, nest);
105	return 0;
106
107nla_failure:
108	nla_nest_cancel(skb, nest);
109	return err;
110}
111
112static int tcp_diag_get_aux(struct sock *sk, bool net_admin,
113			    struct sk_buff *skb)
114{
115	struct inet_connection_sock *icsk = inet_csk(sk);
116	int err = 0;
117
118#ifdef CONFIG_TCP_MD5SIG
119	if (net_admin) {
120		struct tcp_md5sig_info *md5sig;
121
122		rcu_read_lock();
123		md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
124		if (md5sig)
125			err = tcp_diag_put_md5sig(skb, md5sig);
126		rcu_read_unlock();
127		if (err < 0)
128			return err;
129	}
130#endif
131
132	if (net_admin) {
133		const struct tcp_ulp_ops *ulp_ops;
134
135		ulp_ops = icsk->icsk_ulp_ops;
136		if (ulp_ops)
137			err = tcp_diag_put_ulp(skb, sk, ulp_ops);
138		if (err)
139			return err;
140	}
141	return 0;
142}
143
144static size_t tcp_diag_get_aux_size(struct sock *sk, bool net_admin)
145{
146	struct inet_connection_sock *icsk = inet_csk(sk);
147	size_t size = 0;
148
149#ifdef CONFIG_TCP_MD5SIG
150	if (net_admin && sk_fullsock(sk)) {
151		const struct tcp_md5sig_info *md5sig;
152		const struct tcp_md5sig_key *key;
153		size_t md5sig_count = 0;
154
155		rcu_read_lock();
156		md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
157		if (md5sig) {
158			hlist_for_each_entry_rcu(key, &md5sig->head, node)
159				md5sig_count++;
160		}
161		rcu_read_unlock();
162		size += nla_total_size(md5sig_count *
163				       sizeof(struct tcp_diag_md5sig));
164	}
165#endif
166
167	if (net_admin && sk_fullsock(sk)) {
168		const struct tcp_ulp_ops *ulp_ops;
169
170		ulp_ops = icsk->icsk_ulp_ops;
171		if (ulp_ops) {
172			size += nla_total_size(0) +
173				nla_total_size(TCP_ULP_NAME_MAX);
174			if (ulp_ops->get_info_size)
175				size += ulp_ops->get_info_size(sk);
176		}
177	}
178	return size;
179}
180
181static void tcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
182			  const struct inet_diag_req_v2 *r)
183{
184	struct inet_hashinfo *hinfo;
185
186	hinfo = sock_net(cb->skb->sk)->ipv4.tcp_death_row.hashinfo;
187
188	inet_diag_dump_icsk(hinfo, skb, cb, r);
189}
190
191static int tcp_diag_dump_one(struct netlink_callback *cb,
192			     const struct inet_diag_req_v2 *req)
193{
194	struct inet_hashinfo *hinfo;
195
196	hinfo = sock_net(cb->skb->sk)->ipv4.tcp_death_row.hashinfo;
197
198	return inet_diag_dump_one_icsk(hinfo, cb, req);
199}
200
201#ifdef CONFIG_INET_DIAG_DESTROY
202static int tcp_diag_destroy(struct sk_buff *in_skb,
203			    const struct inet_diag_req_v2 *req)
204{
205	struct net *net = sock_net(in_skb->sk);
206	struct inet_hashinfo *hinfo;
207	struct sock *sk;
208	int err;
209
210	hinfo = net->ipv4.tcp_death_row.hashinfo;
211	sk = inet_diag_find_one_icsk(net, hinfo, req);
212
213	if (IS_ERR(sk))
214		return PTR_ERR(sk);
215
216	err = sock_diag_destroy(sk, ECONNABORTED);
217
218	sock_gen_put(sk);
219
220	return err;
221}
222#endif
223
224static const struct inet_diag_handler tcp_diag_handler = {
225	.owner			= THIS_MODULE,
226	.dump			= tcp_diag_dump,
227	.dump_one		= tcp_diag_dump_one,
228	.idiag_get_info		= tcp_diag_get_info,
229	.idiag_get_aux		= tcp_diag_get_aux,
230	.idiag_get_aux_size	= tcp_diag_get_aux_size,
231	.idiag_type		= IPPROTO_TCP,
232	.idiag_info_size	= sizeof(struct tcp_info),
233#ifdef CONFIG_INET_DIAG_DESTROY
234	.destroy		= tcp_diag_destroy,
235#endif
236};
237
238static int __init tcp_diag_init(void)
239{
240	return inet_diag_register(&tcp_diag_handler);
241}
242
243static void __exit tcp_diag_exit(void)
244{
245	inet_diag_unregister(&tcp_diag_handler);
246}
247
248module_init(tcp_diag_init);
249module_exit(tcp_diag_exit);
250MODULE_LICENSE("GPL");
251MODULE_DESCRIPTION("TCP socket monitoring via SOCK_DIAG");
252MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-6 /* AF_INET - IPPROTO_TCP */);
253