l2tp_debugfs.c

  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
 32static struct dentry *rootdir;
 33
 34struct 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
 43static 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
 53static 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
 70static 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
 93out:
 94	return pd;
 95}
 96
 97static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
 98{
 99	(*pos)++;
100	return NULL;
101}
102
103static 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
123static 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 tx %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
176static 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
230static 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
255out:
256	return 0;
257}
258
259static 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
266static 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
292out:
293	return rc;
294
295err_free_net:
296	put_net_track(pd->net, &pd->ns_tracker);
297err_free_pd:
298	kfree(pd);
299	goto out;
300}
301
302static 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
317static 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
325static 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
336static void __exit l2tp_debugfs_exit(void)
337{
338	debugfs_remove_recursive(rootdir);
339}
340
341module_init(l2tp_debugfs_init);
342module_exit(l2tp_debugfs_exit);
343
344MODULE_LICENSE("GPL");
345MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
346MODULE_DESCRIPTION("L2TP debugfs driver");
347MODULE_VERSION("1.0");