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 netns_tracker ns_tracker;
37 unsigned long tkey; /* lookup key of current tunnel */
38 unsigned long skey; /* lookup key of current session */
39 struct l2tp_tunnel *tunnel;
40 struct l2tp_session *session; /* NULL means get next tunnel */
41 };
42
l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data * pd)43 static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
44 {
45 /* Drop reference taken during previous invocation */
46 if (pd->tunnel)
47 l2tp_tunnel_put(pd->tunnel);
48
49 pd->tunnel = l2tp_tunnel_get_next(pd->net, &pd->tkey);
50 pd->tkey++;
51 }
52
l2tp_dfs_next_session(struct l2tp_dfs_seq_data * pd)53 static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
54 {
55 /* Drop reference taken during previous invocation */
56 if (pd->session)
57 l2tp_session_put(pd->session);
58
59 pd->session = l2tp_session_get_next(pd->net, pd->tunnel->sock,
60 pd->tunnel->version,
61 pd->tunnel->tunnel_id, &pd->skey);
62 pd->skey++;
63
64 if (!pd->session) {
65 pd->skey = 0;
66 l2tp_dfs_next_tunnel(pd);
67 }
68 }
69
l2tp_dfs_seq_start(struct seq_file * m,loff_t * offs)70 static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
71 {
72 struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;
73 loff_t pos = *offs;
74
75 if (!pos)
76 goto out;
77
78 if (WARN_ON(!m->private)) {
79 pd = NULL;
80 goto out;
81 }
82 pd = m->private;
83
84 if (!pd->tunnel)
85 l2tp_dfs_next_tunnel(pd);
86 else
87 l2tp_dfs_next_session(pd);
88
89 /* NULL tunnel and session indicates end of list */
90 if (!pd->tunnel && !pd->session)
91 pd = NULL;
92
93 out:
94 return pd;
95 }
96
l2tp_dfs_seq_next(struct seq_file * m,void * v,loff_t * pos)97 static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
98 {
99 (*pos)++;
100 return NULL;
101 }
102
l2tp_dfs_seq_stop(struct seq_file * p,void * v)103 static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
104 {
105 struct l2tp_dfs_seq_data *pd = v;
106
107 if (!pd || pd == SEQ_START_TOKEN)
108 return;
109
110 /* Drop reference taken by last invocation of l2tp_dfs_next_session()
111 * or l2tp_dfs_next_tunnel().
112 */
113 if (pd->session) {
114 l2tp_session_put(pd->session);
115 pd->session = NULL;
116 }
117 if (pd->tunnel) {
118 l2tp_tunnel_put(pd->tunnel);
119 pd->tunnel = NULL;
120 }
121 }
122
l2tp_dfs_seq_tunnel_show(struct seq_file * m,void * v)123 static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
124 {
125 struct l2tp_tunnel *tunnel = v;
126 struct l2tp_session *session;
127 int session_count = 0;
128
129 rcu_read_lock_bh();
130 list_for_each_entry_rcu(session, &tunnel->session_list, list) {
131 /* Session ID of zero is a dummy/reserved value used by pppol2tp */
132 if (session->session_id == 0)
133 continue;
134
135 session_count++;
136 }
137 rcu_read_unlock_bh();
138
139 seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
140 if (tunnel->sock) {
141 struct inet_sock *inet = inet_sk(tunnel->sock);
142
143 #if IS_ENABLED(CONFIG_IPV6)
144 if (tunnel->sock->sk_family == AF_INET6) {
145 const struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
146
147 seq_printf(m, " from %pI6c to %pI6c\n",
148 &np->saddr, &tunnel->sock->sk_v6_daddr);
149 }
150 #endif
151 if (tunnel->sock->sk_family == AF_INET)
152 seq_printf(m, " from %pI4 to %pI4\n",
153 &inet->inet_saddr, &inet->inet_daddr);
154
155 if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
156 seq_printf(m, " source port %hu, dest port %hu\n",
157 ntohs(inet->inet_sport), ntohs(inet->inet_dport));
158 }
159 seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
160 tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
161 tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
162 "");
163 seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
164 tunnel->sock ? refcount_read(&tunnel->sock->sk_refcnt) : 0,
165 refcount_read(&tunnel->ref_count));
166 seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
167 0,
168 atomic_long_read(&tunnel->stats.tx_packets),
169 atomic_long_read(&tunnel->stats.tx_bytes),
170 atomic_long_read(&tunnel->stats.tx_errors),
171 atomic_long_read(&tunnel->stats.rx_packets),
172 atomic_long_read(&tunnel->stats.rx_bytes),
173 atomic_long_read(&tunnel->stats.rx_errors));
174 }
175
l2tp_dfs_seq_session_show(struct seq_file * m,void * v)176 static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
177 {
178 struct l2tp_session *session = v;
179
180 seq_printf(m, " SESSION %u, peer %u, %s\n", session->session_id,
181 session->peer_session_id,
182 session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
183 session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
184 "");
185 if (session->send_seq || session->recv_seq)
186 seq_printf(m, " nr %u, ns %u\n", session->nr, session->ns);
187 seq_printf(m, " refcnt %d\n", refcount_read(&session->ref_count));
188 seq_printf(m, " config 0/0/%c/%c/-/%s %08x %u\n",
189 session->recv_seq ? 'R' : '-',
190 session->send_seq ? 'S' : '-',
191 session->lns_mode ? "LNS" : "LAC",
192 0,
193 jiffies_to_msecs(session->reorder_timeout));
194 seq_printf(m, " offset 0 l2specific %hu/%d\n",
195 session->l2specific_type, l2tp_get_l2specific_len(session));
196 if (session->cookie_len) {
197 seq_printf(m, " cookie %02x%02x%02x%02x",
198 session->cookie[0], session->cookie[1],
199 session->cookie[2], session->cookie[3]);
200 if (session->cookie_len == 8)
201 seq_printf(m, "%02x%02x%02x%02x",
202 session->cookie[4], session->cookie[5],
203 session->cookie[6], session->cookie[7]);
204 seq_puts(m, "\n");
205 }
206 if (session->peer_cookie_len) {
207 seq_printf(m, " peer cookie %02x%02x%02x%02x",
208 session->peer_cookie[0], session->peer_cookie[1],
209 session->peer_cookie[2], session->peer_cookie[3]);
210 if (session->peer_cookie_len == 8)
211 seq_printf(m, "%02x%02x%02x%02x",
212 session->peer_cookie[4], session->peer_cookie[5],
213 session->peer_cookie[6], session->peer_cookie[7]);
214 seq_puts(m, "\n");
215 }
216
217 seq_printf(m, " %u/%u tx %ld/%ld/%ld rx %ld/%ld/%ld\n",
218 session->nr, session->ns,
219 atomic_long_read(&session->stats.tx_packets),
220 atomic_long_read(&session->stats.tx_bytes),
221 atomic_long_read(&session->stats.tx_errors),
222 atomic_long_read(&session->stats.rx_packets),
223 atomic_long_read(&session->stats.rx_bytes),
224 atomic_long_read(&session->stats.rx_errors));
225
226 if (session->show)
227 session->show(m, session);
228 }
229
l2tp_dfs_seq_show(struct seq_file * m,void * v)230 static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
231 {
232 struct l2tp_dfs_seq_data *pd = v;
233
234 /* display header on line 1 */
235 if (v == SEQ_START_TOKEN) {
236 seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
237 seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");
238 seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
239 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
240 seq_puts(m, " SESSION ID, peer ID, PWTYPE\n");
241 seq_puts(m, " refcnt cnt\n");
242 seq_puts(m, " offset OFFSET l2specific TYPE/LEN\n");
243 seq_puts(m, " [ cookie ]\n");
244 seq_puts(m, " [ peer cookie ]\n");
245 seq_puts(m, " config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
246 seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
247 goto out;
248 }
249
250 if (!pd->session)
251 l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
252 else
253 l2tp_dfs_seq_session_show(m, pd->session);
254
255 out:
256 return 0;
257 }
258
259 static const struct seq_operations l2tp_dfs_seq_ops = {
260 .start = l2tp_dfs_seq_start,
261 .next = l2tp_dfs_seq_next,
262 .stop = l2tp_dfs_seq_stop,
263 .show = l2tp_dfs_seq_show,
264 };
265
l2tp_dfs_seq_open(struct inode * inode,struct file * file)266 static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)
267 {
268 struct l2tp_dfs_seq_data *pd;
269 struct seq_file *seq;
270 int rc = -ENOMEM;
271
272 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
273 if (!pd)
274 goto out;
275
276 /* Derive the network namespace from the pid opening the
277 * file.
278 */
279 pd->net = get_net_ns_by_pid(current->pid);
280 if (IS_ERR(pd->net)) {
281 rc = PTR_ERR(pd->net);
282 goto err_free_pd;
283 }
284 netns_tracker_alloc(pd->net, &pd->ns_tracker, GFP_KERNEL);
285 rc = seq_open(file, &l2tp_dfs_seq_ops);
286 if (rc)
287 goto err_free_net;
288
289 seq = file->private_data;
290 seq->private = pd;
291
292 out:
293 return rc;
294
295 err_free_net:
296 put_net_track(pd->net, &pd->ns_tracker);
297 err_free_pd:
298 kfree(pd);
299 goto out;
300 }
301
l2tp_dfs_seq_release(struct inode * inode,struct file * file)302 static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)
303 {
304 struct l2tp_dfs_seq_data *pd;
305 struct seq_file *seq;
306
307 seq = file->private_data;
308 pd = seq->private;
309 if (pd->net)
310 put_net_track(pd->net, &pd->ns_tracker);
311 kfree(pd);
312 seq_release(inode, file);
313
314 return 0;
315 }
316
317 static const struct file_operations l2tp_dfs_fops = {
318 .owner = THIS_MODULE,
319 .open = l2tp_dfs_seq_open,
320 .read = seq_read,
321 .llseek = seq_lseek,
322 .release = l2tp_dfs_seq_release,
323 };
324
l2tp_debugfs_init(void)325 static int __init l2tp_debugfs_init(void)
326 {
327 rootdir = debugfs_create_dir("l2tp", NULL);
328
329 debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);
330
331 pr_info("L2TP debugfs support\n");
332
333 return 0;
334 }
335
l2tp_debugfs_exit(void)336 static void __exit l2tp_debugfs_exit(void)
337 {
338 debugfs_remove_recursive(rootdir);
339 }
340
341 module_init(l2tp_debugfs_init);
342 module_exit(l2tp_debugfs_exit);
343
344 MODULE_LICENSE("GPL");
345 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
346 MODULE_DESCRIPTION("L2TP debugfs driver");
347 MODULE_VERSION("1.0");
348