1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* L2TP subsystem debugfs
3 *
4 * Copyright (c) 2010 Katalix Systems Ltd
5 */
6
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9 #include <linux/module.h>
10 #include <linux/skbuff.h>
11 #include <linux/socket.h>
12 #include <linux/hash.h>
13 #include <linux/l2tp.h>
14 #include <linux/in.h>
15 #include <linux/etherdevice.h>
16 #include <linux/spinlock.h>
17 #include <linux/debugfs.h>
18 #include <net/sock.h>
19 #include <net/ip.h>
20 #include <net/icmp.h>
21 #include <net/udp.h>
22 #include <net/inet_common.h>
23 #include <net/inet_hashtables.h>
24 #include <net/tcp_states.h>
25 #include <net/protocol.h>
26 #include <net/xfrm.h>
27 #include <net/net_namespace.h>
28 #include <net/netns/generic.h>
29
30 #include "l2tp_core.h"
31
32 static struct dentry *rootdir;
33
34 struct l2tp_dfs_seq_data {
35 struct net *net;
36 int tunnel_idx; /* current tunnel */
37 int session_idx; /* index of session within current tunnel */
38 struct l2tp_tunnel *tunnel;
39 struct l2tp_session *session; /* NULL means get next tunnel */
40 };
41
l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data * pd)42 static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
43 {
44 /* Drop reference taken during previous invocation */
45 if (pd->tunnel)
46 l2tp_tunnel_dec_refcount(pd->tunnel);
47
48 pd->tunnel = l2tp_tunnel_get_nth(pd->net, pd->tunnel_idx);
49 pd->tunnel_idx++;
50 }
51
l2tp_dfs_next_session(struct l2tp_dfs_seq_data * pd)52 static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
53 {
54 /* Drop reference taken during previous invocation */
55 if (pd->session)
56 l2tp_session_dec_refcount(pd->session);
57
58 pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
59 pd->session_idx++;
60
61 if (!pd->session) {
62 pd->session_idx = 0;
63 l2tp_dfs_next_tunnel(pd);
64 }
65 }
66
l2tp_dfs_seq_start(struct seq_file * m,loff_t * offs)67 static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
68 {
69 struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;
70 loff_t pos = *offs;
71
72 if (!pos)
73 goto out;
74
75 if (WARN_ON(!m->private)) {
76 pd = NULL;
77 goto out;
78 }
79 pd = m->private;
80
81 if (!pd->tunnel)
82 l2tp_dfs_next_tunnel(pd);
83 else
84 l2tp_dfs_next_session(pd);
85
86 /* NULL tunnel and session indicates end of list */
87 if (!pd->tunnel && !pd->session)
88 pd = NULL;
89
90 out:
91 return pd;
92 }
93
l2tp_dfs_seq_next(struct seq_file * m,void * v,loff_t * pos)94 static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
95 {
96 (*pos)++;
97 return NULL;
98 }
99
l2tp_dfs_seq_stop(struct seq_file * p,void * v)100 static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
101 {
102 struct l2tp_dfs_seq_data *pd = v;
103
104 if (!pd || pd == SEQ_START_TOKEN)
105 return;
106
107 /* Drop reference taken by last invocation of l2tp_dfs_next_session()
108 * or l2tp_dfs_next_tunnel().
109 */
110 if (pd->session) {
111 l2tp_session_dec_refcount(pd->session);
112 pd->session = NULL;
113 }
114 if (pd->tunnel) {
115 l2tp_tunnel_dec_refcount(pd->tunnel);
116 pd->tunnel = NULL;
117 }
118 }
119
l2tp_dfs_seq_tunnel_show(struct seq_file * m,void * v)120 static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
121 {
122 struct l2tp_tunnel *tunnel = v;
123 int session_count = 0;
124 int hash;
125 struct hlist_node *walk;
126 struct hlist_node *tmp;
127
128 read_lock_bh(&tunnel->hlist_lock);
129 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
130 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
131 struct l2tp_session *session;
132
133 session = hlist_entry(walk, struct l2tp_session, hlist);
134 if (session->session_id == 0)
135 continue;
136
137 session_count++;
138 }
139 }
140 read_unlock_bh(&tunnel->hlist_lock);
141
142 seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
143 if (tunnel->sock) {
144 struct inet_sock *inet = inet_sk(tunnel->sock);
145
146 #if IS_ENABLED(CONFIG_IPV6)
147 if (tunnel->sock->sk_family == AF_INET6) {
148 const struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
149
150 seq_printf(m, " from %pI6c to %pI6c\n",
151 &np->saddr, &tunnel->sock->sk_v6_daddr);
152 }
153 #endif
154 if (tunnel->sock->sk_family == AF_INET)
155 seq_printf(m, " from %pI4 to %pI4\n",
156 &inet->inet_saddr, &inet->inet_daddr);
157
158 if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
159 seq_printf(m, " source port %hu, dest port %hu\n",
160 ntohs(inet->inet_sport), ntohs(inet->inet_dport));
161 }
162 seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
163 tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
164 tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
165 "");
166 seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
167 tunnel->sock ? refcount_read(&tunnel->sock->sk_refcnt) : 0,
168 refcount_read(&tunnel->ref_count));
169 seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
170 0,
171 atomic_long_read(&tunnel->stats.tx_packets),
172 atomic_long_read(&tunnel->stats.tx_bytes),
173 atomic_long_read(&tunnel->stats.tx_errors),
174 atomic_long_read(&tunnel->stats.rx_packets),
175 atomic_long_read(&tunnel->stats.rx_bytes),
176 atomic_long_read(&tunnel->stats.rx_errors));
177 }
178
l2tp_dfs_seq_session_show(struct seq_file * m,void * v)179 static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
180 {
181 struct l2tp_session *session = v;
182
183 seq_printf(m, " SESSION %u, peer %u, %s\n", session->session_id,
184 session->peer_session_id,
185 session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
186 session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
187 "");
188 if (session->send_seq || session->recv_seq)
189 seq_printf(m, " nr %hu, ns %hu\n", session->nr, session->ns);
190 seq_printf(m, " refcnt %d\n", refcount_read(&session->ref_count));
191 seq_printf(m, " config 0/0/%c/%c/-/%s %08x %u\n",
192 session->recv_seq ? 'R' : '-',
193 session->send_seq ? 'S' : '-',
194 session->lns_mode ? "LNS" : "LAC",
195 0,
196 jiffies_to_msecs(session->reorder_timeout));
197 seq_printf(m, " offset 0 l2specific %hu/%hu\n",
198 session->l2specific_type, l2tp_get_l2specific_len(session));
199 if (session->cookie_len) {
200 seq_printf(m, " cookie %02x%02x%02x%02x",
201 session->cookie[0], session->cookie[1],
202 session->cookie[2], session->cookie[3]);
203 if (session->cookie_len == 8)
204 seq_printf(m, "%02x%02x%02x%02x",
205 session->cookie[4], session->cookie[5],
206 session->cookie[6], session->cookie[7]);
207 seq_puts(m, "\n");
208 }
209 if (session->peer_cookie_len) {
210 seq_printf(m, " peer cookie %02x%02x%02x%02x",
211 session->peer_cookie[0], session->peer_cookie[1],
212 session->peer_cookie[2], session->peer_cookie[3]);
213 if (session->peer_cookie_len == 8)
214 seq_printf(m, "%02x%02x%02x%02x",
215 session->peer_cookie[4], session->peer_cookie[5],
216 session->peer_cookie[6], session->peer_cookie[7]);
217 seq_puts(m, "\n");
218 }
219
220 seq_printf(m, " %hu/%hu tx %ld/%ld/%ld rx %ld/%ld/%ld\n",
221 session->nr, session->ns,
222 atomic_long_read(&session->stats.tx_packets),
223 atomic_long_read(&session->stats.tx_bytes),
224 atomic_long_read(&session->stats.tx_errors),
225 atomic_long_read(&session->stats.rx_packets),
226 atomic_long_read(&session->stats.rx_bytes),
227 atomic_long_read(&session->stats.rx_errors));
228
229 if (session->show)
230 session->show(m, session);
231 }
232
l2tp_dfs_seq_show(struct seq_file * m,void * v)233 static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
234 {
235 struct l2tp_dfs_seq_data *pd = v;
236
237 /* display header on line 1 */
238 if (v == SEQ_START_TOKEN) {
239 seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
240 seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");
241 seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
242 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
243 seq_puts(m, " SESSION ID, peer ID, PWTYPE\n");
244 seq_puts(m, " refcnt cnt\n");
245 seq_puts(m, " offset OFFSET l2specific TYPE/LEN\n");
246 seq_puts(m, " [ cookie ]\n");
247 seq_puts(m, " [ peer cookie ]\n");
248 seq_puts(m, " config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
249 seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
250 goto out;
251 }
252
253 if (!pd->session)
254 l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
255 else
256 l2tp_dfs_seq_session_show(m, pd->session);
257
258 out:
259 return 0;
260 }
261
262 static const struct seq_operations l2tp_dfs_seq_ops = {
263 .start = l2tp_dfs_seq_start,
264 .next = l2tp_dfs_seq_next,
265 .stop = l2tp_dfs_seq_stop,
266 .show = l2tp_dfs_seq_show,
267 };
268
l2tp_dfs_seq_open(struct inode * inode,struct file * file)269 static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)
270 {
271 struct l2tp_dfs_seq_data *pd;
272 struct seq_file *seq;
273 int rc = -ENOMEM;
274
275 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
276 if (!pd)
277 goto out;
278
279 /* Derive the network namespace from the pid opening the
280 * file.
281 */
282 pd->net = get_net_ns_by_pid(current->pid);
283 if (IS_ERR(pd->net)) {
284 rc = PTR_ERR(pd->net);
285 goto err_free_pd;
286 }
287
288 rc = seq_open(file, &l2tp_dfs_seq_ops);
289 if (rc)
290 goto err_free_net;
291
292 seq = file->private_data;
293 seq->private = pd;
294
295 out:
296 return rc;
297
298 err_free_net:
299 put_net(pd->net);
300 err_free_pd:
301 kfree(pd);
302 goto out;
303 }
304
l2tp_dfs_seq_release(struct inode * inode,struct file * file)305 static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)
306 {
307 struct l2tp_dfs_seq_data *pd;
308 struct seq_file *seq;
309
310 seq = file->private_data;
311 pd = seq->private;
312 if (pd->net)
313 put_net(pd->net);
314 kfree(pd);
315 seq_release(inode, file);
316
317 return 0;
318 }
319
320 static const struct file_operations l2tp_dfs_fops = {
321 .owner = THIS_MODULE,
322 .open = l2tp_dfs_seq_open,
323 .read = seq_read,
324 .llseek = seq_lseek,
325 .release = l2tp_dfs_seq_release,
326 };
327
l2tp_debugfs_init(void)328 static int __init l2tp_debugfs_init(void)
329 {
330 rootdir = debugfs_create_dir("l2tp", NULL);
331
332 debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);
333
334 pr_info("L2TP debugfs support\n");
335
336 return 0;
337 }
338
l2tp_debugfs_exit(void)339 static void __exit l2tp_debugfs_exit(void)
340 {
341 debugfs_remove_recursive(rootdir);
342 }
343
344 module_init(l2tp_debugfs_init);
345 module_exit(l2tp_debugfs_exit);
346
347 MODULE_LICENSE("GPL");
348 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
349 MODULE_DESCRIPTION("L2TP debugfs driver");
350 MODULE_VERSION("1.0");
351