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