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, attrtype: INET_DIAG_MD5SIG,
69 attrlen: md5sig_count * sizeof(struct tcp_diag_md5sig));
70 if (!attr)
71 return -EMSGSIZE;
72
73 info = nla_data(nla: 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: 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, attrtype: INET_DIAG_ULP_INFO);
92 if (!nest)
93 return -EMSGSIZE;
94
95 err = nla_put_string(skb, attrtype: INET_ULP_INFO_NAME, str: 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, start: nest);
105 return 0;
106
107nla_failure:
108 nla_nest_cancel(skb, start: 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(payload: 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(payload: 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(sk: cb->skb->sk)->ipv4.tcp_death_row.hashinfo;
187
188 inet_diag_dump_icsk(h: 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(sk: cb->skb->sk)->ipv4.tcp_death_row.hashinfo;
197
198 return inet_diag_dump_one_icsk(hashinfo: 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(sk: 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, hashinfo: hinfo, req);
212
213 if (IS_ERR(ptr: sk))
214 return PTR_ERR(ptr: 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 .dump = tcp_diag_dump,
226 .dump_one = tcp_diag_dump_one,
227 .idiag_get_info = tcp_diag_get_info,
228 .idiag_get_aux = tcp_diag_get_aux,
229 .idiag_get_aux_size = tcp_diag_get_aux_size,
230 .idiag_type = IPPROTO_TCP,
231 .idiag_info_size = sizeof(struct tcp_info),
232#ifdef CONFIG_INET_DIAG_DESTROY
233 .destroy = tcp_diag_destroy,
234#endif
235};
236
237static int __init tcp_diag_init(void)
238{
239 return inet_diag_register(handler: &tcp_diag_handler);
240}
241
242static void __exit tcp_diag_exit(void)
243{
244 inet_diag_unregister(handler: &tcp_diag_handler);
245}
246
247module_init(tcp_diag_init);
248module_exit(tcp_diag_exit);
249MODULE_LICENSE("GPL");
250MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-6 /* AF_INET - IPPROTO_TCP */);
251

source code of linux/net/ipv4/tcp_diag.c