xref: /openbmc/linux/net/l2tp/l2tp_debugfs.c (revision be709d48) 
1 /*
2  * L2TP subsystem debugfs
3  *
4  * Copyright (c) 2010 Katalix Systems Ltd
5  *
6  *	This program is free software; you can redistribute it and/or
7  *	modify it under the terms of the GNU General Public License
8  *	as published by the Free Software Foundation; either version
9  *	2 of the License, or (at your option) any later version.
10  */
11 
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 
14 #include <linux/module.h>
15 #include <linux/skbuff.h>
16 #include <linux/socket.h>
17 #include <linux/hash.h>
18 #include <linux/l2tp.h>
19 #include <linux/in.h>
20 #include <linux/etherdevice.h>
21 #include <linux/spinlock.h>
22 #include <linux/debugfs.h>
23 #include <net/sock.h>
24 #include <net/ip.h>
25 #include <net/icmp.h>
26 #include <net/udp.h>
27 #include <net/inet_common.h>
28 #include <net/inet_hashtables.h>
29 #include <net/tcp_states.h>
30 #include <net/protocol.h>
31 #include <net/xfrm.h>
32 #include <net/net_namespace.h>
33 #include <net/netns/generic.h>
34 
35 #include "l2tp_core.h"
36 
37 static struct dentry *rootdir;
38 static struct dentry *tunnels;
39 
40 struct l2tp_dfs_seq_data {
41 	struct net *net;
42 	int tunnel_idx;			/* current tunnel */
43 	int session_idx;		/* index of session within current tunnel */
44 	struct l2tp_tunnel *tunnel;
45 	struct l2tp_session *session;	/* NULL means get next tunnel */
46 };
47 
48 static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
49 {
50 	/* Drop reference taken during previous invocation */
51 	if (pd->tunnel)
52 		l2tp_tunnel_dec_refcount(pd->tunnel);
53 
54 	pd->tunnel = l2tp_tunnel_get_nth(pd->net, pd->tunnel_idx);
55 	pd->tunnel_idx++;
56 }
57 
58 static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
59 {
60 	/* Drop reference taken during previous invocation */
61 	if (pd->session)
62 		l2tp_session_dec_refcount(pd->session);
63 
64 	pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
65 	pd->session_idx++;
66 
67 	if (pd->session == NULL) {
68 		pd->session_idx = 0;
69 		l2tp_dfs_next_tunnel(pd);
70 	}
71 
72 }
73 
74 static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
75 {
76 	struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;
77 	loff_t pos = *offs;
78 
79 	if (!pos)
80 		goto out;
81 
82 	BUG_ON(m->private == NULL);
83 	pd = m->private;
84 
85 	if (pd->tunnel == NULL)
86 		l2tp_dfs_next_tunnel(pd);
87 	else
88 		l2tp_dfs_next_session(pd);
89 
90 	/* NULL tunnel and session indicates end of list */
91 	if ((pd->tunnel == NULL) && (pd->session == NULL))
92 		pd = NULL;
93 
94 out:
95 	return pd;
96 }
97 
98 
99 static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
100 {
101 	(*pos)++;
102 	return NULL;
103 }
104 
105 static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
106 {
107 	struct l2tp_dfs_seq_data *pd = v;
108 
109 	if (!pd || pd == SEQ_START_TOKEN)
110 		return;
111 
112 	/* Drop reference taken by last invocation of l2tp_dfs_next_session()
113 	 * or l2tp_dfs_next_tunnel().
114 	 */
115 	if (pd->session) {
116 		l2tp_session_dec_refcount(pd->session);
117 		pd->session = NULL;
118 	}
119 	if (pd->tunnel) {
120 		l2tp_tunnel_dec_refcount(pd->tunnel);
121 		pd->tunnel = NULL;
122 	}
123 }
124 
125 static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
126 {
127 	struct l2tp_tunnel *tunnel = v;
128 	int session_count = 0;
129 	int hash;
130 	struct hlist_node *walk;
131 	struct hlist_node *tmp;
132 
133 	read_lock_bh(&tunnel->hlist_lock);
134 	for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
135 		hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
136 			struct l2tp_session *session;
137 
138 			session = hlist_entry(walk, struct l2tp_session, hlist);
139 			if (session->session_id == 0)
140 				continue;
141 
142 			session_count++;
143 		}
144 	}
145 	read_unlock_bh(&tunnel->hlist_lock);
146 
147 	seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
148 	if (tunnel->sock) {
149 		struct inet_sock *inet = inet_sk(tunnel->sock);
150 
151 #if IS_ENABLED(CONFIG_IPV6)
152 		if (tunnel->sock->sk_family == AF_INET6) {
153 			const struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
154 
155 			seq_printf(m, " from %pI6c to %pI6c\n",
156 				&np->saddr, &tunnel->sock->sk_v6_daddr);
157 		} else
158 #endif
159 		seq_printf(m, " from %pI4 to %pI4\n",
160 			   &inet->inet_saddr, &inet->inet_daddr);
161 		if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
162 			seq_printf(m, " source port %hu, dest port %hu\n",
163 				   ntohs(inet->inet_sport), ntohs(inet->inet_dport));
164 	}
165 	seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
166 		   tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
167 		   tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
168 		   "");
169 	seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
170 		   tunnel->sock ? refcount_read(&tunnel->sock->sk_refcnt) : 0,
171 		   refcount_read(&tunnel->ref_count));
172 	seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
173 		   tunnel->debug,
174 		   atomic_long_read(&tunnel->stats.tx_packets),
175 		   atomic_long_read(&tunnel->stats.tx_bytes),
176 		   atomic_long_read(&tunnel->stats.tx_errors),
177 		   atomic_long_read(&tunnel->stats.rx_packets),
178 		   atomic_long_read(&tunnel->stats.rx_bytes),
179 		   atomic_long_read(&tunnel->stats.rx_errors));
180 }
181 
182 static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
183 {
184 	struct l2tp_session *session = v;
185 
186 	seq_printf(m, "  SESSION %u, peer %u, %s\n", session->session_id,
187 		   session->peer_session_id,
188 		   session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
189 		   session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
190 		   "");
191 	if (session->send_seq || session->recv_seq)
192 		seq_printf(m, "   nr %hu, ns %hu\n", session->nr, session->ns);
193 	seq_printf(m, "   refcnt %d\n", refcount_read(&session->ref_count));
194 	seq_printf(m, "   config 0/0/%c/%c/-/%s %08x %u\n",
195 		   session->recv_seq ? 'R' : '-',
196 		   session->send_seq ? 'S' : '-',
197 		   session->lns_mode ? "LNS" : "LAC",
198 		   session->debug,
199 		   jiffies_to_msecs(session->reorder_timeout));
200 	seq_printf(m, "   offset 0 l2specific %hu/%hu\n",
201 		   session->l2specific_type, l2tp_get_l2specific_len(session));
202 	if (session->cookie_len) {
203 		seq_printf(m, "   cookie %02x%02x%02x%02x",
204 			   session->cookie[0], session->cookie[1],
205 			   session->cookie[2], session->cookie[3]);
206 		if (session->cookie_len == 8)
207 			seq_printf(m, "%02x%02x%02x%02x",
208 				   session->cookie[4], session->cookie[5],
209 				   session->cookie[6], session->cookie[7]);
210 		seq_printf(m, "\n");
211 	}
212 	if (session->peer_cookie_len) {
213 		seq_printf(m, "   peer cookie %02x%02x%02x%02x",
214 			   session->peer_cookie[0], session->peer_cookie[1],
215 			   session->peer_cookie[2], session->peer_cookie[3]);
216 		if (session->peer_cookie_len == 8)
217 			seq_printf(m, "%02x%02x%02x%02x",
218 				   session->peer_cookie[4], session->peer_cookie[5],
219 				   session->peer_cookie[6], session->peer_cookie[7]);
220 		seq_printf(m, "\n");
221 	}
222 
223 	seq_printf(m, "   %hu/%hu tx %ld/%ld/%ld rx %ld/%ld/%ld\n",
224 		   session->nr, session->ns,
225 		   atomic_long_read(&session->stats.tx_packets),
226 		   atomic_long_read(&session->stats.tx_bytes),
227 		   atomic_long_read(&session->stats.tx_errors),
228 		   atomic_long_read(&session->stats.rx_packets),
229 		   atomic_long_read(&session->stats.rx_bytes),
230 		   atomic_long_read(&session->stats.rx_errors));
231 
232 	if (session->show != NULL)
233 		session->show(m, session);
234 }
235 
236 static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
237 {
238 	struct l2tp_dfs_seq_data *pd = v;
239 
240 	/* display header on line 1 */
241 	if (v == SEQ_START_TOKEN) {
242 		seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
243 		seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");
244 		seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
245 		seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
246 		seq_puts(m, "  SESSION ID, peer ID, PWTYPE\n");
247 		seq_puts(m, "   refcnt cnt\n");
248 		seq_puts(m, "   offset OFFSET l2specific TYPE/LEN\n");
249 		seq_puts(m, "   [ cookie ]\n");
250 		seq_puts(m, "   [ peer cookie ]\n");
251 		seq_puts(m, "   config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
252 		seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
253 		goto out;
254 	}
255 
256 	if (!pd->session)
257 		l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
258 	else
259 		l2tp_dfs_seq_session_show(m, pd->session);
260 
261 out:
262 	return 0;
263 }
264 
265 static const struct seq_operations l2tp_dfs_seq_ops = {
266 	.start		= l2tp_dfs_seq_start,
267 	.next		= l2tp_dfs_seq_next,
268 	.stop		= l2tp_dfs_seq_stop,
269 	.show		= l2tp_dfs_seq_show,
270 };
271 
272 static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)
273 {
274 	struct l2tp_dfs_seq_data *pd;
275 	struct seq_file *seq;
276 	int rc = -ENOMEM;
277 
278 	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
279 	if (pd == NULL)
280 		goto out;
281 
282 	/* Derive the network namespace from the pid opening the
283 	 * file.
284 	 */
285 	pd->net = get_net_ns_by_pid(current->pid);
286 	if (IS_ERR(pd->net)) {
287 		rc = PTR_ERR(pd->net);
288 		goto err_free_pd;
289 	}
290 
291 	rc = seq_open(file, &l2tp_dfs_seq_ops);
292 	if (rc)
293 		goto err_free_net;
294 
295 	seq = file->private_data;
296 	seq->private = pd;
297 
298 out:
299 	return rc;
300 
301 err_free_net:
302 	put_net(pd->net);
303 err_free_pd:
304 	kfree(pd);
305 	goto out;
306 }
307 
308 static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)
309 {
310 	struct l2tp_dfs_seq_data *pd;
311 	struct seq_file *seq;
312 
313 	seq = file->private_data;
314 	pd = seq->private;
315 	if (pd->net)
316 		put_net(pd->net);
317 	kfree(pd);
318 	seq_release(inode, file);
319 
320 	return 0;
321 }
322 
323 static const struct file_operations l2tp_dfs_fops = {
324 	.owner		= THIS_MODULE,
325 	.open		= l2tp_dfs_seq_open,
326 	.read		= seq_read,
327 	.llseek		= seq_lseek,
328 	.release	= l2tp_dfs_seq_release,
329 };
330 
331 static int __init l2tp_debugfs_init(void)
332 {
333 	int rc = 0;
334 
335 	rootdir = debugfs_create_dir("l2tp", NULL);
336 	if (IS_ERR(rootdir)) {
337 		rc = PTR_ERR(rootdir);
338 		rootdir = NULL;
339 		goto out;
340 	}
341 
342 	tunnels = debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);
343 	if (tunnels == NULL)
344 		rc = -EIO;
345 
346 	pr_info("L2TP debugfs support\n");
347 
348 out:
349 	if (rc)
350 		pr_warn("unable to init\n");
351 
352 	return rc;
353 }
354 
355 static void __exit l2tp_debugfs_exit(void)
356 {
357 	debugfs_remove(tunnels);
358 	debugfs_remove(rootdir);
359 }
360 
361 module_init(l2tp_debugfs_init);
362 module_exit(l2tp_debugfs_exit);
363 
364 MODULE_LICENSE("GPL");
365 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
366 MODULE_DESCRIPTION("L2TP debugfs driver");
367 MODULE_VERSION("1.0");
368