xref: /openbmc/linux/net/l2tp/l2tp_debugfs.c (revision 9d899dbe)
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