[PATCH 3/5] net: pppol2tp - introduce net-namespace functionality

From: Cyrill Gorcunov
Date: Tue Jan 20 2009 - 09:15:51 EST

- Each tunnel and appropriate lock are inside own namespace now.
- pppox code allows to create per-namespace sockets for
both PX_PROTO_OE and PX_PROTO_OL2TP protocols. Actually since
now pppox_create support net-namespaces new PPPo... protocols
(if they ever will be) should support net-namespace too otherwise
explicit check for &init_net would be needed.

CC: James Chapman <jchapman@xxxxxxxxxxx>
Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
---
drivers/net/pppol2tp.c | 160 +++++++++++++++++++++++++++++++++++--------------
drivers/net/pppox.c | 4 -
2 files changed, 117 insertions(+), 47 deletions(-)

Index: linux-2.6.git/drivers/net/pppol2tp.c
===================================================================
--- linux-2.6.git.orig/drivers/net/pppol2tp.c
+++ linux-2.6.git/drivers/net/pppol2tp.c
@@ -90,7 +90,9 @@
#include <linux/hash.h>
#include <linux/sort.h>
#include <linux/proc_fs.h>
+#include <linux/nsproxy.h>
#include <net/net_namespace.h>
+#include <net/netns/generic.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/udp.h>
@@ -204,6 +206,7 @@ struct pppol2tp_tunnel
struct sock *sock; /* Parent socket */
struct list_head list; /* Keep a list of all open
* prepared sockets */
+ struct net *pppol2tp_net; /* the net we belong to */

atomic_t ref_count;
};
@@ -227,8 +230,20 @@ static atomic_t pppol2tp_tunnel_count;
static atomic_t pppol2tp_session_count;
static struct ppp_channel_ops pppol2tp_chan_ops = { pppol2tp_xmit , NULL };
static struct proto_ops pppol2tp_ops;
-static LIST_HEAD(pppol2tp_tunnel_list);
-static DEFINE_RWLOCK(pppol2tp_tunnel_list_lock);
+
+/* per-net private data for this module */
+static unsigned int pppol2tp_net_id;
+struct pppol2tp_net {
+ struct list_head pppol2tp_tunnel_list;
+ rwlock_t pppol2tp_tunnel_list_lock;
+};
+
+static inline struct pppol2tp_net *pppol2tp_pernet(struct net *net)
+{
+ BUG_ON(!net);
+
+ return net_generic(net, pppol2tp_net_id);
+}

/* Helpers to obtain tunnel/session contexts from sockets.
*/
@@ -321,18 +336,19 @@ pppol2tp_session_find(struct pppol2tp_tu

/* Lookup a tunnel by id
*/
-static struct pppol2tp_tunnel *pppol2tp_tunnel_find(u16 tunnel_id)
+static struct pppol2tp_tunnel *pppol2tp_tunnel_find(struct net *net, u16 tunnel_id)
{
- struct pppol2tp_tunnel *tunnel = NULL;
+ struct pppol2tp_tunnel *tunnel;
+ struct pppol2tp_net *pn = pppol2tp_pernet(net);

- read_lock_bh(&pppol2tp_tunnel_list_lock);
- list_for_each_entry(tunnel, &pppol2tp_tunnel_list, list) {
+ read_lock_bh(&pn->pppol2tp_tunnel_list_lock);
+ list_for_each_entry(tunnel, &pn->pppol2tp_tunnel_list, list) {
if (tunnel->stats.tunnel_id == tunnel_id) {
- read_unlock_bh(&pppol2tp_tunnel_list_lock);
+ read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
return tunnel;
}
}
- read_unlock_bh(&pppol2tp_tunnel_list_lock);
+ read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);

return NULL;
}
@@ -1287,10 +1303,12 @@ again:
*/
static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel)
{
+ struct pppol2tp_net *pn = pppol2tp_pernet(tunnel->pppol2tp_net);
+
/* Remove from socket list */
- write_lock_bh(&pppol2tp_tunnel_list_lock);
+ write_lock_bh(&pn->pppol2tp_tunnel_list_lock);
list_del_init(&tunnel->list);
- write_unlock_bh(&pppol2tp_tunnel_list_lock);
+ write_unlock_bh(&pn->pppol2tp_tunnel_list_lock);

atomic_dec(&pppol2tp_tunnel_count);
kfree(tunnel);
@@ -1444,13 +1462,14 @@ error:
/* Internal function to prepare a tunnel (UDP) socket to have PPPoX
* sockets attached to it.
*/
-static struct sock *pppol2tp_prepare_tunnel_socket(int fd, u16 tunnel_id,
- int *error)
+static struct sock *pppol2tp_prepare_tunnel_socket(struct net *net,
+ int fd, u16 tunnel_id, int *error)
{
int err;
struct socket *sock = NULL;
struct sock *sk;
struct pppol2tp_tunnel *tunnel;
+ struct pppol2tp_net *pn;
struct sock *ret = NULL;

/* Get the tunnel UDP socket from the fd, which was opened by
@@ -1524,11 +1543,15 @@ static struct sock *pppol2tp_prepare_tun
/* Misc init */
rwlock_init(&tunnel->hlist_lock);

+ /* The net we belong to */
+ tunnel->pppol2tp_net = net;
+ pn = pppol2tp_pernet(net);
+
/* Add tunnel to our list */
INIT_LIST_HEAD(&tunnel->list);
- write_lock_bh(&pppol2tp_tunnel_list_lock);
- list_add(&tunnel->list, &pppol2tp_tunnel_list);
- write_unlock_bh(&pppol2tp_tunnel_list_lock);
+ write_lock_bh(&pn->pppol2tp_tunnel_list_lock);
+ list_add(&tunnel->list, &pn->pppol2tp_tunnel_list);
+ write_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
atomic_inc(&pppol2tp_tunnel_count);

/* Bump the reference count. The tunnel context is deleted
@@ -1629,7 +1652,8 @@ static int pppol2tp_connect(struct socke
* tunnel id.
*/
if ((sp->pppol2tp.s_session == 0) && (sp->pppol2tp.d_session == 0)) {
- tunnel_sock = pppol2tp_prepare_tunnel_socket(sp->pppol2tp.fd,
+ tunnel_sock = pppol2tp_prepare_tunnel_socket(sock_net(sk),
+ sp->pppol2tp.fd,
sp->pppol2tp.s_tunnel,
&error);
if (tunnel_sock == NULL)
@@ -1637,7 +1661,7 @@ static int pppol2tp_connect(struct socke

tunnel = tunnel_sock->sk_user_data;
} else {
- tunnel = pppol2tp_tunnel_find(sp->pppol2tp.s_tunnel);
+ tunnel = pppol2tp_tunnel_find(sock_net(sk), sp->pppol2tp.s_tunnel);

/* Error if we can't find the tunnel */
error = -ENOENT;
@@ -2347,8 +2371,9 @@ end:
#include <linux/seq_file.h>

struct pppol2tp_seq_data {
- struct pppol2tp_tunnel *tunnel; /* current tunnel */
- struct pppol2tp_session *session; /* NULL means get first session in tunnel */
+ struct net *seq_net; /* net of inode */
+ struct pppol2tp_tunnel *tunnel; /* current tunnel */
+ struct pppol2tp_session *session; /* NULL means get first session in tunnel */
};

static struct pppol2tp_session *next_session(struct pppol2tp_tunnel *tunnel, struct pppol2tp_session *curr)
@@ -2384,17 +2409,18 @@ out:
return session;
}

-static struct pppol2tp_tunnel *next_tunnel(struct pppol2tp_tunnel *curr)
+static struct pppol2tp_tunnel *next_tunnel(struct pppol2tp_net *pn,
+ struct pppol2tp_tunnel *curr)
{
struct pppol2tp_tunnel *tunnel = NULL;

- read_lock_bh(&pppol2tp_tunnel_list_lock);
- if (list_is_last(&curr->list, &pppol2tp_tunnel_list)) {
+ read_lock_bh(&pn->pppol2tp_tunnel_list_lock);
+ if (list_is_last(&curr->list, &pn->pppol2tp_tunnel_list)) {
goto out;
}
tunnel = list_entry(curr->list.next, struct pppol2tp_tunnel, list);
out:
- read_unlock_bh(&pppol2tp_tunnel_list_lock);
+ read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);

return tunnel;
}
@@ -2402,6 +2428,7 @@ out:
static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
{
struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
+ struct pppol2tp_net *pn;
loff_t pos = *offs;

if (!pos)
@@ -2409,14 +2436,15 @@ static void *pppol2tp_seq_start(struct s

BUG_ON(m->private == NULL);
pd = m->private;
+ pn = pppol2tp_pernet(pd->seq_net);

if (pd->tunnel == NULL) {
- if (!list_empty(&pppol2tp_tunnel_list))
- pd->tunnel = list_entry(pppol2tp_tunnel_list.next, struct pppol2tp_tunnel, list);
+ if (!list_empty(&pn->pppol2tp_tunnel_list))
+ pd->tunnel = list_entry(pn->pppol2tp_tunnel_list.next, struct pppol2tp_tunnel, list);
} else {
pd->session = next_session(pd->tunnel, pd->session);
if (pd->session == NULL) {
- pd->tunnel = next_tunnel(pd->tunnel);
+ pd->tunnel = next_tunnel(pn, pd->tunnel);
}
}

@@ -2532,6 +2560,7 @@ static int pppol2tp_proc_open(struct ino
{
struct seq_file *m;
struct pppol2tp_seq_data *pd;
+ struct net *net;
int ret = 0;

ret = seq_open(file, &pppol2tp_seq_ops);
@@ -2542,12 +2571,15 @@ static int pppol2tp_proc_open(struct ino

/* Allocate and fill our proc_data for access later */
ret = -ENOMEM;
- m->private = kzalloc(sizeof(struct pppol2tp_seq_data), GFP_KERNEL);
+ m->private = kzalloc(sizeof(*pd), GFP_KERNEL);
if (m->private == NULL)
goto out;

pd = m->private;
- ret = 0;
+ net = maybe_get_net(PDE_NET(PDE(inode)));
+ BUG_ON(!net);
+ pd->seq_net = net;
+ return 0;

out:
return ret;
@@ -2558,6 +2590,9 @@ out:
static int pppol2tp_proc_release(struct inode *inode, struct file *file)
{
struct seq_file *m = (struct seq_file *)file->private_data;
+ struct pppol2tp_seq_data *pd = m->private;
+
+ put_net(pd->seq_net);

kfree(m->private);
m->private = NULL;
@@ -2573,8 +2608,6 @@ static struct file_operations pppol2tp_p
.release = pppol2tp_proc_release,
};

-static struct proc_dir_entry *pppol2tp_proc;
-
#endif /* CONFIG_PROC_FS */

/*****************************************************************************
@@ -2606,6 +2639,57 @@ static struct pppox_proto pppol2tp_proto
.ioctl = pppol2tp_ioctl
};

+static __net_init int pppol2tp_init_net(struct net *net)
+{
+ struct pppol2tp_net *pn;
+ struct proc_dir_entry *pde;
+ int err;
+
+ pn = kzalloc(sizeof(*pn), GFP_KERNEL);
+ if (!pn)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&pn->pppol2tp_tunnel_list);
+ rwlock_init(&pn->pppol2tp_tunnel_list_lock);
+
+ err = net_assign_generic(net, pppol2tp_net_id, pn);
+ if (err)
+ goto out;
+
+ pde = proc_net_fops_create(net, "pppol2tp", S_IRUGO, &pppol2tp_proc_fops);
+#ifdef CONFIG_PROC_FS
+ if (!pde) {
+ err = -ENOMEM;
+ goto out;
+ }
+#endif
+
+ return 0;
+
+out:
+ kfree(pn);
+ return err;
+}
+
+static __net_exit void pppol2tp_exit_net(struct net *net)
+{
+ struct pppoe_net *pn;
+
+ proc_net_remove(net, "pppol2tp");
+ pn = net_generic(net, pppol2tp_net_id);
+ /*
+ * if someone has cached our net then
+ * further net_generic call will return NULL
+ */
+ net_assign_generic(net, pppol2tp_net_id, NULL);
+ kfree(pn);
+}
+
+static __net_initdata struct pernet_operations pppol2tp_net_ops = {
+ .init = pppol2tp_init_net,
+ .exit = pppol2tp_exit_net,
+};
+
static int __init pppol2tp_init(void)
{
int err;
@@ -2617,23 +2701,17 @@ static int __init pppol2tp_init(void)
if (err)
goto out_unregister_pppol2tp_proto;

-#ifdef CONFIG_PROC_FS
- pppol2tp_proc = proc_net_fops_create(&init_net, "pppol2tp", 0,
- &pppol2tp_proc_fops);
- if (!pppol2tp_proc) {
- err = -ENOMEM;
+ err = register_pernet_gen_device(&pppol2tp_net_id, &pppol2tp_net_ops);
+ if (err)
goto out_unregister_pppox_proto;
- }
-#endif /* CONFIG_PROC_FS */
+
printk(KERN_INFO "PPPoL2TP kernel driver, %s\n",
PPPOL2TP_DRV_VERSION);

out:
return err;
-#ifdef CONFIG_PROC_FS
out_unregister_pppox_proto:
unregister_pppox_proto(PX_PROTO_OL2TP);
-#endif
out_unregister_pppol2tp_proto:
proto_unregister(&pppol2tp_sk_proto);
goto out;
@@ -2642,10 +2720,6 @@ out_unregister_pppol2tp_proto:
static void __exit pppol2tp_exit(void)
{
unregister_pppox_proto(PX_PROTO_OL2TP);
-
-#ifdef CONFIG_PROC_FS
- remove_proc_entry("pppol2tp", init_net.proc_net);
-#endif
proto_unregister(&pppol2tp_sk_proto);
}

Index: linux-2.6.git/drivers/net/pppox.c
===================================================================
--- linux-2.6.git.orig/drivers/net/pppox.c
+++ linux-2.6.git/drivers/net/pppox.c
@@ -111,10 +111,6 @@ static int pppox_create(struct net *net,
if (protocol < 0 || protocol > PX_MAX_PROTO)
goto out;

- /* we support net-namespaces for PPPoE only (yet) */
- if (protocol != PX_PROTO_OE && net != &init_net)
- return -EAFNOSUPPORT;
-
rc = -EPROTONOSUPPORT;
if (!pppox_protos[protocol])
request_module("pppox-proto-%d", protocol);

--
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