net: pppol2tp - introduce net-namespace functionality

- 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.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 117 insertions, 43 deletions

diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c
index 635dd5fbe62d..f3f9cb1f77c0 100644
--- a/drivers/net/pppol2tp.c
+++ b/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_tunnel *tunnel, u16 session_id)
 
 /* 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_tunnel_socket(int fd, u16 tunnel_id,
         /* 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 socket *sock, struct sockaddr *uservaddr,
          * 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 socket *sock, struct sockaddr *uservaddr,
 
                 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 seq_file *m, loff_t *offs)
 
         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 inode *inode, struct file *file)
 {
         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 inode *inode, struct file *file)
 
         /* 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 const struct file_operations pppol2tp_proc_fops = {
         .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);
 }