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
18 static 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
38 static 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
55 static 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
85 static 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
107 nla_failure:
108 nla_nest_cancel(skb, nest);
109 return err;
110 }
111
112 static 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
144 static 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
181 static 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
191 static 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
202 static 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
224 static 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
238 static int __init tcp_diag_init(void)
239 {
240 return inet_diag_register(&tcp_diag_handler);
241 }
242
243 static void __exit tcp_diag_exit(void)
244 {
245 inet_diag_unregister(&tcp_diag_handler);
246 }
247
248 module_init(tcp_diag_init);
249 module_exit(tcp_diag_exit);
250 MODULE_LICENSE("GPL");
251 MODULE_DESCRIPTION("TCP socket monitoring via SOCK_DIAG");
252 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-6 /* AF_INET - IPPROTO_TCP */);
253
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