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
37static struct dentry *rootdir;
38static struct dentry *tunnels;
39
40struct 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
48static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
49{
50	pd->tunnel = l2tp_tunnel_find_nth(pd->net, pd->tunnel_idx);
51	pd->tunnel_idx++;
52}
53
54static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
55{
56	pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx);
57	pd->session_idx++;
58
59	if (pd->session == NULL) {
60		pd->session_idx = 0;
61		l2tp_dfs_next_tunnel(pd);
62	}
63
64}
65
66static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
67{
68	struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;
69	loff_t pos = *offs;
70
71	if (!pos)
72		goto out;
73
74	BUG_ON(m->private == NULL);
75	pd = m->private;
76
77	if (pd->tunnel == NULL)
78		l2tp_dfs_next_tunnel(pd);
79	else
80		l2tp_dfs_next_session(pd);
81
82	/* NULL tunnel and session indicates end of list */
83	if ((pd->tunnel == NULL) && (pd->session == NULL))
84		pd = NULL;
85
86out:
87	return pd;
88}
89
90
91static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
92{
93	(*pos)++;
94	return NULL;
95}
96
97static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
98{
99	/* nothing to do */
100}
101
102static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
103{
104	struct l2tp_tunnel *tunnel = v;
105	int session_count = 0;
106	int hash;
107	struct hlist_node *walk;
108	struct hlist_node *tmp;
109
110	read_lock_bh(&tunnel->hlist_lock);
111	for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
112		hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
113			struct l2tp_session *session;
114
115			session = hlist_entry(walk, struct l2tp_session, hlist);
116			if (session->session_id == 0)
117				continue;
118
119			session_count++;
120		}
121	}
122	read_unlock_bh(&tunnel->hlist_lock);
123
124	seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
125	if (tunnel->sock) {
126		struct inet_sock *inet = inet_sk(tunnel->sock);
127
128#if IS_ENABLED(CONFIG_IPV6)
129		if (tunnel->sock->sk_family == AF_INET6) {
130			const struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
131
132			seq_printf(m, " from %pI6c to %pI6c\n",
133				&np->saddr, &tunnel->sock->sk_v6_daddr);
134		} else
135#endif
136		seq_printf(m, " from %pI4 to %pI4\n",
137			   &inet->inet_saddr, &inet->inet_daddr);
138		if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
139			seq_printf(m, " source port %hu, dest port %hu\n",
140				   ntohs(inet->inet_sport), ntohs(inet->inet_dport));
141	}
142	seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
143		   tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
144		   tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
145		   "");
146	seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
147		   tunnel->sock ? atomic_read(&tunnel->sock->sk_refcnt) : 0,
148		   atomic_read(&tunnel->ref_count));
149
150	seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
151		   tunnel->debug,
152		   atomic_long_read(&tunnel->stats.tx_packets),
153		   atomic_long_read(&tunnel->stats.tx_bytes),
154		   atomic_long_read(&tunnel->stats.tx_errors),
155		   atomic_long_read(&tunnel->stats.rx_packets),
156		   atomic_long_read(&tunnel->stats.rx_bytes),
157		   atomic_long_read(&tunnel->stats.rx_errors));
158
159	if (tunnel->show != NULL)
160		tunnel->show(m, tunnel);
161}
162
163static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
164{
165	struct l2tp_session *session = v;
166
167	seq_printf(m, "  SESSION %u, peer %u, %s\n", session->session_id,
168		   session->peer_session_id,
169		   session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
170		   session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
171		   "");
172	if (session->send_seq || session->recv_seq)
173		seq_printf(m, "   nr %hu, ns %hu\n", session->nr, session->ns);
174	seq_printf(m, "   refcnt %d\n", atomic_read(&session->ref_count));
175	seq_printf(m, "   config %d/%d/%c/%c/%s/%s %08x %u\n",
176		   session->mtu, session->mru,
177		   session->recv_seq ? 'R' : '-',
178		   session->send_seq ? 'S' : '-',
179		   session->data_seq == 1 ? "IPSEQ" :
180		   session->data_seq == 2 ? "DATASEQ" : "-",
181		   session->lns_mode ? "LNS" : "LAC",
182		   session->debug,
183		   jiffies_to_msecs(session->reorder_timeout));
184	seq_printf(m, "   offset %hu l2specific %hu/%hu\n",
185		   session->offset, session->l2specific_type, session->l2specific_len);
186	if (session->cookie_len) {
187		seq_printf(m, "   cookie %02x%02x%02x%02x",
188			   session->cookie[0], session->cookie[1],
189			   session->cookie[2], session->cookie[3]);
190		if (session->cookie_len == 8)
191			seq_printf(m, "%02x%02x%02x%02x",
192				   session->cookie[4], session->cookie[5],
193				   session->cookie[6], session->cookie[7]);
194		seq_printf(m, "\n");
195	}
196	if (session->peer_cookie_len) {
197		seq_printf(m, "   peer cookie %02x%02x%02x%02x",
198			   session->peer_cookie[0], session->peer_cookie[1],
199			   session->peer_cookie[2], session->peer_cookie[3]);
200		if (session->peer_cookie_len == 8)
201			seq_printf(m, "%02x%02x%02x%02x",
202				   session->peer_cookie[4], session->peer_cookie[5],
203				   session->peer_cookie[6], session->peer_cookie[7]);
204		seq_printf(m, "\n");
205	}
206
207	seq_printf(m, "   %hu/%hu tx %ld/%ld/%ld rx %ld/%ld/%ld\n",
208		   session->nr, session->ns,
209		   atomic_long_read(&session->stats.tx_packets),
210		   atomic_long_read(&session->stats.tx_bytes),
211		   atomic_long_read(&session->stats.tx_errors),
212		   atomic_long_read(&session->stats.rx_packets),
213		   atomic_long_read(&session->stats.rx_bytes),
214		   atomic_long_read(&session->stats.rx_errors));
215
216	if (session->show != NULL)
217		session->show(m, session);
218}
219
220static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
221{
222	struct l2tp_dfs_seq_data *pd = v;
223
224	/* display header on line 1 */
225	if (v == SEQ_START_TOKEN) {
226		seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
227		seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");
228		seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
229		seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
230		seq_puts(m, "  SESSION ID, peer ID, PWTYPE\n");
231		seq_puts(m, "   refcnt cnt\n");
232		seq_puts(m, "   offset OFFSET l2specific TYPE/LEN\n");
233		seq_puts(m, "   [ cookie ]\n");
234		seq_puts(m, "   [ peer cookie ]\n");
235		seq_puts(m, "   config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
236		seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
237		goto out;
238	}
239
240	/* Show the tunnel or session context */
241	if (pd->session == NULL)
242		l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
243	else
244		l2tp_dfs_seq_session_show(m, pd->session);
245
246out:
247	return 0;
248}
249
250static const struct seq_operations l2tp_dfs_seq_ops = {
251	.start		= l2tp_dfs_seq_start,
252	.next		= l2tp_dfs_seq_next,
253	.stop		= l2tp_dfs_seq_stop,
254	.show		= l2tp_dfs_seq_show,
255};
256
257static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)
258{
259	struct l2tp_dfs_seq_data *pd;
260	struct seq_file *seq;
261	int rc = -ENOMEM;
262
263	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
264	if (pd == NULL)
265		goto out;
266
267	/* Derive the network namespace from the pid opening the
268	 * file.
269	 */
270	pd->net = get_net_ns_by_pid(current->pid);
271	if (IS_ERR(pd->net)) {
272		rc = PTR_ERR(pd->net);
273		goto err_free_pd;
274	}
275
276	rc = seq_open(file, &l2tp_dfs_seq_ops);
277	if (rc)
278		goto err_free_net;
279
280	seq = file->private_data;
281	seq->private = pd;
282
283out:
284	return rc;
285
286err_free_net:
287	put_net(pd->net);
288err_free_pd:
289	kfree(pd);
290	goto out;
291}
292
293static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)
294{
295	struct l2tp_dfs_seq_data *pd;
296	struct seq_file *seq;
297
298	seq = file->private_data;
299	pd = seq->private;
300	if (pd->net)
301		put_net(pd->net);
302	kfree(pd);
303	seq_release(inode, file);
304
305	return 0;
306}
307
308static const struct file_operations l2tp_dfs_fops = {
309	.owner		= THIS_MODULE,
310	.open		= l2tp_dfs_seq_open,
311	.read		= seq_read,
312	.llseek		= seq_lseek,
313	.release	= l2tp_dfs_seq_release,
314};
315
316static int __init l2tp_debugfs_init(void)
317{
318	int rc = 0;
319
320	rootdir = debugfs_create_dir("l2tp", NULL);
321	if (IS_ERR(rootdir)) {
322		rc = PTR_ERR(rootdir);
323		rootdir = NULL;
324		goto out;
325	}
326
327	tunnels = debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);
328	if (tunnels == NULL)
329		rc = -EIO;
330
331	pr_info("L2TP debugfs support\n");
332
333out:
334	if (rc)
335		pr_warn("unable to init\n");
336
337	return rc;
338}
339
340static void __exit l2tp_debugfs_exit(void)
341{
342	debugfs_remove(tunnels);
343	debugfs_remove(rootdir);
344}
345
346module_init(l2tp_debugfs_init);
347module_exit(l2tp_debugfs_exit);
348
349MODULE_LICENSE("GPL");
350MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
351MODULE_DESCRIPTION("L2TP debugfs driver");
352MODULE_VERSION("1.0");
353