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Commit 0ad66140 authored by James Chapman's avatar James Chapman Committed by David S. Miller
Browse files

l2tp: Add debugfs files for dumping l2tp debug info 



The existing pppol2tp driver exports debug info to
/proc/net/pppol2tp. Rather than adding info to that file for the new
functionality added in this patch series, we add new files in debugfs,
leaving the old /proc file for backwards compatibility (L2TPv2 only).

Currently only one file is provided: l2tp/tunnels, which lists
internal debug info for all l2tp tunnels and sessions. More files may
be added later. The info is for debug and problem analysis only -
userspace apps should use netlink to obtain status about l2tp tunnels
and sessions.

Although debugfs does not support net namespaces, the tunnels and
sessions dumped in l2tp/tunnels are only those in the net namespace of
the process reading the file.

Signed-off-by: default avatarJames Chapman <jchapman@katalix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d9e31d17

net/l2tp/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -31,6 +31,19 @@ menuconfig L2TP 
	  If you don't need L2TP, say N. To compile all L2TP code as

	  modules, choose M here.



config L2TP_DEBUGFS

	tristate "L2TP debugfs support"

	depends on L2TP && DEBUG_FS

	help

	  Support for l2tp directory in debugfs filesystem. This may be

	  used to dump internal state of the l2tp drivers for problem

	  analysis.



	  If unsure, say 'Y'.



	  To compile this driver as a module, choose M here. The module

	  will be called l2tp_debugfs.



config L2TP_V3

	bool "L2TPv3 support (EXPERIMENTAL)"

	depends on EXPERIMENTAL && L2TP

net/l2tp/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -9,3 +9,4 @@ obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_PPPOL2TP)) += l2tp_ppp.o 
obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_IP)) += l2tp_ip.o

obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_V3)) += l2tp_netlink.o

obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_ETH)) += l2tp_eth.o

obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_DEBUGFS)) += l2tp_debugfs.o

net/l2tp/l2tp_core.h

+6 −2
Original line number Diff line number Diff line
@@ -133,7 +133,9 @@ struct l2tp_session { 
	void (*session_close)(struct l2tp_session *session);

	void (*ref)(struct l2tp_session *session);

	void (*deref)(struct l2tp_session *session);



#ifdef CONFIG_L2TP_DEBUGFS

	void (*show)(struct seq_file *m, void *priv);

#endif

	uint8_t			priv[0];	/* private data */

};
@@ -166,7 +168,9 @@ struct l2tp_tunnel { 
	struct net		*l2tp_net;	/* the net we belong to */



	atomic_t		ref_count;



#ifdef CONFIG_DEBUG_FS

	void (*show)(struct seq_file *m, void *arg);

#endif

	int (*recv_payload_hook)(struct sk_buff *skb);

	void (*old_sk_destruct)(struct sock *);

	struct sock		*sock;		/* Parent socket */

net/l2tp/l2tp_debugfs.c

0 → 100644
+341 −0
Original line number Diff line number Diff line 
/*

 * L2TP subsystem debugfs

 *

 * Copyright (c) 2010 Katalix Systems Ltd

 *

 *	This program is free software; you can redistribute it and/or

 *	modify it under the terms of the GNU General Public License

 *	as published by the Free Software Foundation; either version

 *	2 of the License, or (at your option) any later version.

 */



#include <linux/module.h>

#include <linux/skbuff.h>

#include <linux/socket.h>

#include <linux/hash.h>

#include <linux/l2tp.h>

#include <linux/in.h>

#include <linux/etherdevice.h>

#include <linux/spinlock.h>

#include <linux/debugfs.h>

#include <net/sock.h>

#include <net/ip.h>

#include <net/icmp.h>

#include <net/udp.h>

#include <net/inet_common.h>

#include <net/inet_hashtables.h>

#include <net/tcp_states.h>

#include <net/protocol.h>

#include <net/xfrm.h>

#include <net/net_namespace.h>

#include <net/netns/generic.h>



#include "l2tp_core.h"



static struct dentry *rootdir;

static struct dentry *tunnels;



struct l2tp_dfs_seq_data {

	struct net *net;

	int tunnel_idx;			/* current tunnel */

	int session_idx;		/* index of session within current tunnel */

	struct l2tp_tunnel *tunnel;

	struct l2tp_session *session;	/* NULL means get next tunnel */

};



static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)

{

	pd->tunnel = l2tp_tunnel_find_nth(pd->net, pd->tunnel_idx);

	pd->tunnel_idx++;

}



static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)

{

	pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx);

	pd->session_idx++;



	if (pd->session == NULL) {

		pd->session_idx = 0;

		l2tp_dfs_next_tunnel(pd);

	}



}



static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)

{

	struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;

	loff_t pos = *offs;



	if (!pos)

		goto out;



	BUG_ON(m->private == NULL);

	pd = m->private;



	if (pd->tunnel == NULL)

		l2tp_dfs_next_tunnel(pd);

	else

		l2tp_dfs_next_session(pd);



	/* NULL tunnel and session indicates end of list */

	if ((pd->tunnel == NULL) && (pd->session == NULL))

		pd = NULL;



out:

	return pd;

}





static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)

{

	(*pos)++;

	return NULL;

}



static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)

{

	/* nothing to do */

}



static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)

{

	struct l2tp_tunnel *tunnel = v;

	int session_count = 0;

	int hash;

	struct hlist_node *walk;

	struct hlist_node *tmp;



	read_lock_bh(&tunnel->hlist_lock);

	for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {

		hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {

			struct l2tp_session *session;



			session = hlist_entry(walk, struct l2tp_session, hlist);

			if (session->session_id == 0)

				continue;



			session_count++;

		}

	}

	read_unlock_bh(&tunnel->hlist_lock);



	seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);

	if (tunnel->sock) {

		struct inet_sock *inet = inet_sk(tunnel->sock);

		seq_printf(m, " from " NIPQUAD_FMT " to " NIPQUAD_FMT "\n",

			   NIPQUAD(inet->inet_saddr), NIPQUAD(inet->inet_daddr));

		if (tunnel->encap == L2TP_ENCAPTYPE_UDP)

			seq_printf(m, " source port %hu, dest port %hu\n",

				   ntohs(inet->inet_sport), ntohs(inet->inet_dport));

	}

	seq_printf(m, " L2TPv%d, %s\n", tunnel->version,

		   tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :

		   tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :

		   "");

	seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,

		   tunnel->sock ? atomic_read(&tunnel->sock->sk_refcnt) : 0,

		   atomic_read(&tunnel->ref_count));



	seq_printf(m, " %08x rx %llu/%llu/%llu rx %llu/%llu/%llu\n",

		   tunnel->debug,

		   (unsigned long long)tunnel->stats.tx_packets,

		   (unsigned long long)tunnel->stats.tx_bytes,

		   (unsigned long long)tunnel->stats.tx_errors,

		   (unsigned long long)tunnel->stats.rx_packets,

		   (unsigned long long)tunnel->stats.rx_bytes,

		   (unsigned long long)tunnel->stats.rx_errors);



	if (tunnel->show != NULL)

		tunnel->show(m, tunnel);

}



static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)

{

	struct l2tp_session *session = v;



	seq_printf(m, "  SESSION %u, peer %u, %s\n", session->session_id,

		   session->peer_session_id,

		   session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :

		   session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :

		   "");

	if (session->send_seq || session->recv_seq)

		seq_printf(m, "   nr %hu, ns %hu\n", session->nr, session->ns);

	seq_printf(m, "   refcnt %d\n", atomic_read(&session->ref_count));

	seq_printf(m, "   config %d/%d/%c/%c/%s/%s %08x %u\n",

		   session->mtu, session->mru,

		   session->recv_seq ? 'R' : '-',

		   session->send_seq ? 'S' : '-',

		   session->data_seq == 1 ? "IPSEQ" :

		   session->data_seq == 2 ? "DATASEQ" : "-",

		   session->lns_mode ? "LNS" : "LAC",

		   session->debug,

		   jiffies_to_msecs(session->reorder_timeout));

	seq_printf(m, "   offset %hu l2specific %hu/%hu\n",

		   session->offset, session->l2specific_type, session->l2specific_len);

	if (session->cookie_len) {

		seq_printf(m, "   cookie %02x%02x%02x%02x",

			   session->cookie[0], session->cookie[1],

			   session->cookie[2], session->cookie[3]);

		if (session->cookie_len == 8)

			seq_printf(m, "%02x%02x%02x%02x",

				   session->cookie[4], session->cookie[5],

				   session->cookie[6], session->cookie[7]);

		seq_printf(m, "\n");

	}

	if (session->peer_cookie_len) {

		seq_printf(m, "   peer cookie %02x%02x%02x%02x",

			   session->peer_cookie[0], session->peer_cookie[1],

			   session->peer_cookie[2], session->peer_cookie[3]);

		if (session->peer_cookie_len == 8)

			seq_printf(m, "%02x%02x%02x%02x",

				   session->peer_cookie[4], session->peer_cookie[5],

				   session->peer_cookie[6], session->peer_cookie[7]);

		seq_printf(m, "\n");

	}



	seq_printf(m, "   %hu/%hu tx %llu/%llu/%llu rx %llu/%llu/%llu\n",

		   session->nr, session->ns,

		   (unsigned long long)session->stats.tx_packets,

		   (unsigned long long)session->stats.tx_bytes,

		   (unsigned long long)session->stats.tx_errors,

		   (unsigned long long)session->stats.rx_packets,

		   (unsigned long long)session->stats.rx_bytes,

		   (unsigned long long)session->stats.rx_errors);



	if (session->show != NULL)

		session->show(m, session);

}



static int l2tp_dfs_seq_show(struct seq_file *m, void *v)

{

	struct l2tp_dfs_seq_data *pd = v;



	/* display header on line 1 */

	if (v == SEQ_START_TOKEN) {

		seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");

		seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");

		seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");

		seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");

		seq_puts(m, "  SESSION ID, peer ID, PWTYPE\n");

		seq_puts(m, "   refcnt cnt\n");

		seq_puts(m, "   offset OFFSET l2specific TYPE/LEN\n");

		seq_puts(m, "   [ cookie ]\n");

		seq_puts(m, "   [ peer cookie ]\n");

		seq_puts(m, "   config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");

		seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");

		goto out;

	}



	/* Show the tunnel or session context */

	if (pd->session == NULL)

		l2tp_dfs_seq_tunnel_show(m, pd->tunnel);

	else

		l2tp_dfs_seq_session_show(m, pd->session);



out:

	return 0;

}



static const struct seq_operations l2tp_dfs_seq_ops = {

	.start		= l2tp_dfs_seq_start,

	.next		= l2tp_dfs_seq_next,

	.stop		= l2tp_dfs_seq_stop,

	.show		= l2tp_dfs_seq_show,

};



static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)

{

	struct l2tp_dfs_seq_data *pd;

	struct seq_file *seq;

	int rc = -ENOMEM;



	pd = kzalloc(GFP_KERNEL, sizeof(*pd));

	if (pd == NULL)

		goto out;



	/* Derive the network namespace from the pid opening the

	 * file.

	 */

	pd->net = get_net_ns_by_pid(current->pid);

	if (IS_ERR(pd->net)) {

		rc = -PTR_ERR(pd->net);

		goto err_free_pd;

	}



	rc = seq_open(file, &l2tp_dfs_seq_ops);

	if (rc)

		goto err_free_net;



	seq = file->private_data;

	seq->private = pd;



out:

	return rc;



err_free_net:

	put_net(pd->net);

err_free_pd:

	kfree(pd);

	goto out;

}



static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)

{

	struct l2tp_dfs_seq_data *pd;

	struct seq_file *seq;



	seq = file->private_data;

	pd = seq->private;

	if (pd->net)

		put_net(pd->net);

	kfree(pd);

	seq_release(inode, file);



	return 0;

}



static const struct file_operations l2tp_dfs_fops = {

	.owner		= THIS_MODULE,

	.open		= l2tp_dfs_seq_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= l2tp_dfs_seq_release,

};



static int __init l2tp_debugfs_init(void)

{

	int rc = 0;



	rootdir = debugfs_create_dir("l2tp", NULL);

	if (IS_ERR(rootdir)) {

		rc = PTR_ERR(rootdir);

		rootdir = NULL;

		goto out;

	}



	tunnels = debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);

	if (tunnels == NULL)

		rc = -EIO;



	printk(KERN_INFO "L2TP debugfs support\n");



out:

	if (rc)

		printk(KERN_WARNING "l2tp debugfs: unable to init\n");



	return rc;

}



static void __exit l2tp_debugfs_exit(void)

{

	debugfs_remove(tunnels);

	debugfs_remove(rootdir);

}



module_init(l2tp_debugfs_init);

module_exit(l2tp_debugfs_exit);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");

MODULE_DESCRIPTION("L2TP debugfs driver");

MODULE_VERSION("1.0");

net/l2tp/l2tp_eth.c

+14 −0
Original line number Diff line number Diff line
@@ -172,6 +172,17 @@ static void l2tp_eth_delete(struct l2tp_session *session) 
	}

}



#ifdef CONFIG_L2TP_DEBUGFS

static void l2tp_eth_show(struct seq_file *m, void *arg)

{

	struct l2tp_session *session = arg;

	struct l2tp_eth_sess *spriv = l2tp_session_priv(session);

	struct net_device *dev = spriv->dev;



	seq_printf(m, "   interface %s\n", dev->name);

}

#endif



static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)

{

	struct net_device *dev;
@@ -233,6 +244,9 @@ static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 p 
	priv->tunnel_sock = tunnel->sock;

	session->recv_skb = l2tp_eth_dev_recv;

	session->session_close = l2tp_eth_delete;

#ifdef CONFIG_L2TP_DEBUGFS

	session->show = l2tp_eth_show;

#endif



	spriv = l2tp_session_priv(session);

	spriv->dev = dev;