net: ppp_generic - introduce net-namespace functionality v2

- Each namespace contains ppp channels and units separately
  with appropriate locks

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

2 files changed, 202 insertions, 77 deletions

diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 7b2728b8f1b7..4405a76ed3da 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -49,6 +49,10 @@
 #include <net/slhc_vj.h>
 #include <asm/atomic.h>
 
+#include <linux/nsproxy.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
 #define PPP_VERSION     "2.4.2"
 
 /*
@@ -131,6 +135,7 @@ struct ppp {
         struct sock_filter *active_filter;/* filter for pkts to reset idle */
         unsigned pass_len, active_len;
 #endif /* CONFIG_PPP_FILTER */
+        struct net      *ppp_net;       /* the net we belong to */
 };
 
 /*
@@ -155,6 +160,7 @@ struct channel {
         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
         struct ppp      *ppp;           /* ppp unit we're connected to */
+        struct net      *chan_net;      /* the net channel belongs to */
         struct list_head clist;         /* link in list of channels per unit */
         rwlock_t        upl;            /* protects `ppp' */
 #ifdef CONFIG_PPP_MULTILINK
@@ -173,26 +179,35 @@ struct channel {
  * channel.downl.
  */
 
-/*
- * all_ppp_mutex protects the all_ppp_units mapping.
- * It also ensures that finding a ppp unit in the all_ppp_units map
- * and updating its file.refcnt field is atomic.
- */
-static DEFINE_MUTEX(all_ppp_mutex);
 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
-static DEFINE_IDR(ppp_units_idr);
-
-/*
- * all_channels_lock protects all_channels and last_channel_index,
- * and the atomicity of find a channel and updating its file.refcnt
- * field.
- */
-static DEFINE_SPINLOCK(all_channels_lock);
-static LIST_HEAD(all_channels);
-static LIST_HEAD(new_channels);
-static int last_channel_index;
 static atomic_t channel_count = ATOMIC_INIT(0);
 
+/* per-net private data for this module */
+static unsigned int ppp_net_id;
+struct ppp_net {
+        /* units to ppp mapping */
+        struct idr units_idr;
+
+        /*
+         * all_ppp_mutex protects the units_idr mapping.
+         * It also ensures that finding a ppp unit in the units_idr
+         * map and updating its file.refcnt field is atomic.
+         */
+        struct mutex all_ppp_mutex;
+
+        /* channels */
+        struct list_head all_channels;
+        struct list_head new_channels;
+        int last_channel_index;
+
+        /*
+         * all_channels_lock protects all_channels and
+         * last_channel_index, and the atomicity of find
+         * a channel and updating its file.refcnt field.
+         */
+        spinlock_t all_channels_lock;
+};
+
 /* Get the PPP protocol number from a skb */
 #define PPP_PROTO(skb)  (((skb)->data[0] << 8) + (skb)->data[1])
 
@@ -216,8 +231,8 @@ static atomic_t channel_count = ATOMIC_INIT(0);
 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
 
 /* Prototypes. */
-static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
-                                unsigned int cmd, unsigned long arg);
+static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
+                        struct file *file, unsigned int cmd, unsigned long arg);
 static void ppp_xmit_process(struct ppp *ppp);
 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
 static void ppp_push(struct ppp *ppp);
@@ -240,12 +255,12 @@ static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 static void ppp_ccp_closed(struct ppp *ppp);
 static struct compressor *find_compressor(int type);
 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
-static struct ppp *ppp_create_interface(int unit, int *retp);
+static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
 static void init_ppp_file(struct ppp_file *pf, int kind);
 static void ppp_shutdown_interface(struct ppp *ppp);
 static void ppp_destroy_interface(struct ppp *ppp);
-static struct ppp *ppp_find_unit(int unit);
-static struct channel *ppp_find_channel(int unit);
+static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
+static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 static int ppp_connect_channel(struct channel *pch, int unit);
 static int ppp_disconnect_channel(struct channel *pch);
 static void ppp_destroy_channel(struct channel *pch);
@@ -256,6 +271,14 @@ static void *unit_find(struct idr *p, int n);
 
 static struct class *ppp_class;
 
+/* per net-namespace data */
+static inline struct ppp_net *ppp_pernet(struct net *net)
+{
+        BUG_ON(!net);
+
+        return net_generic(net, ppp_net_id);
+}
+
 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 static inline int proto_to_npindex(int proto)
 {
@@ -544,7 +567,8 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         int __user *p = argp;
 
         if (!pf)
-                return ppp_unattached_ioctl(pf, file, cmd, arg);
+                return ppp_unattached_ioctl(current->nsproxy->net_ns,
+                                        pf, file, cmd, arg);
 
         if (cmd == PPPIOCDETACH) {
                 /*
@@ -763,12 +787,13 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         return err;
 }
 
-static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
-                                unsigned int cmd, unsigned long arg)
+static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
+                        struct file *file, unsigned int cmd, unsigned long arg)
 {
         int unit, err = -EFAULT;
         struct ppp *ppp;
         struct channel *chan;
+        struct ppp_net *pn;
         int __user *p = (int __user *)arg;
 
         lock_kernel();
@@ -777,7 +802,7 @@ static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
                 /* Create a new ppp unit */
                 if (get_user(unit, p))
                         break;
-                ppp = ppp_create_interface(unit, &err);
+                ppp = ppp_create_interface(net, unit, &err);
                 if (!ppp)
                         break;
                 file->private_data = &ppp->file;
@@ -792,29 +817,31 @@ static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
                 /* Attach to an existing ppp unit */
                 if (get_user(unit, p))
                         break;
-                mutex_lock(&all_ppp_mutex);
                 err = -ENXIO;
-                ppp = ppp_find_unit(unit);
+                pn = ppp_pernet(net);
+                mutex_lock(&pn->all_ppp_mutex);
+                ppp = ppp_find_unit(pn, unit);
                 if (ppp) {
                         atomic_inc(&ppp->file.refcnt);
                         file->private_data = &ppp->file;
                         err = 0;
                 }
-                mutex_unlock(&all_ppp_mutex);
+                mutex_unlock(&pn->all_ppp_mutex);
                 break;
 
         case PPPIOCATTCHAN:
                 if (get_user(unit, p))
                         break;
-                spin_lock_bh(&all_channels_lock);
                 err = -ENXIO;
-                chan = ppp_find_channel(unit);
+                pn = ppp_pernet(net);
+                spin_lock_bh(&pn->all_channels_lock);
+                chan = ppp_find_channel(pn, unit);
                 if (chan) {
                         atomic_inc(&chan->file.refcnt);
                         file->private_data = &chan->file;
                         err = 0;
                 }
-                spin_unlock_bh(&all_channels_lock);
+                spin_unlock_bh(&pn->all_channels_lock);
                 break;
 
         default:
@@ -834,6 +861,51 @@ static const struct file_operations ppp_device_fops = {
         .release        = ppp_release
 };
 
+static __net_init int ppp_init_net(struct net *net)
+{
+        struct ppp_net *pn;
+        int err;
+
+        pn = kzalloc(sizeof(*pn), GFP_KERNEL);
+        if (!pn)
+                return -ENOMEM;
+
+        idr_init(&pn->units_idr);
+        mutex_init(&pn->all_ppp_mutex);
+
+        INIT_LIST_HEAD(&pn->all_channels);
+        INIT_LIST_HEAD(&pn->new_channels);
+
+        spin_lock_init(&pn->all_channels_lock);
+
+        err = net_assign_generic(net, ppp_net_id, pn);
+        if (err) {
+                kfree(pn);
+                return err;
+        }
+
+        return 0;
+}
+
+static __net_exit void ppp_exit_net(struct net *net)
+{
+        struct ppp_net *pn;
+
+        pn = net_generic(net, ppp_net_id);
+        idr_destroy(&pn->units_idr);
+        /*
+         * if someone has cached our net then
+         * further net_generic call will return NULL
+         */
+        net_assign_generic(net, ppp_net_id, NULL);
+        kfree(pn);
+}
+
+static __net_initdata struct pernet_operations ppp_net_ops = {
+        .init = ppp_init_net,
+        .exit = ppp_exit_net,
+};
+
 #define PPP_MAJOR       108
 
 /* Called at boot time if ppp is compiled into the kernel,
@@ -843,25 +915,36 @@ static int __init ppp_init(void)
         int err;
 
         printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
-        err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
-        if (!err) {
-                ppp_class = class_create(THIS_MODULE, "ppp");
-                if (IS_ERR(ppp_class)) {
-                        err = PTR_ERR(ppp_class);
-                        goto out_chrdev;
-                }
-                device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL,
-                              "ppp");
+
+        err = register_pernet_gen_device(&ppp_net_id, &ppp_net_ops);
+        if (err) {
+                printk(KERN_ERR "failed to register PPP pernet device (%d)\n", err);
+                goto out;
         }
 
-out:
-        if (err)
+        err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
+        if (err) {
                 printk(KERN_ERR "failed to register PPP device (%d)\n", err);
-        return err;
+                goto out_net;
+        }
+
+        ppp_class = class_create(THIS_MODULE, "ppp");
+        if (IS_ERR(ppp_class)) {
+                err = PTR_ERR(ppp_class);
+                goto out_chrdev;
+        }
+
+        /* not a big deal if we fail here :-) */
+        device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
+
+        return 0;
 
 out_chrdev:
         unregister_chrdev(PPP_MAJOR, "ppp");
-        goto out;
+out_net:
+        unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
+out:
+        return err;
 }
 
 /*
@@ -969,6 +1052,7 @@ static void ppp_setup(struct net_device *dev)
         dev->tx_queue_len = 3;
         dev->type = ARPHRD_PPP;
         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
+        dev->features |= NETIF_F_NETNS_LOCAL;
 }
 
 /*
@@ -1986,19 +2070,27 @@ ppp_mp_reconstruct(struct ppp *ppp)
  * Channel interface.
  */
 
-/*
- * Create a new, unattached ppp channel.
- */
-int
-ppp_register_channel(struct ppp_channel *chan)
+/* Create a new, unattached ppp channel. */
+int ppp_register_channel(struct ppp_channel *chan)
+{
+        return ppp_register_net_channel(current->nsproxy->net_ns, chan);
+}
+
+/* Create a new, unattached ppp channel for specified net. */
+int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
 {
         struct channel *pch;
+        struct ppp_net *pn;
 
         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
         if (!pch)
                 return -ENOMEM;
+
+        pn = ppp_pernet(net);
+
         pch->ppp = NULL;
         pch->chan = chan;
+        pch->chan_net = net;
         chan->ppp = pch;
         init_ppp_file(&pch->file, CHANNEL);
         pch->file.hdrlen = chan->hdrlen;
@@ -2008,11 +2100,13 @@ ppp_register_channel(struct ppp_channel *chan)
         init_rwsem(&pch->chan_sem);
         spin_lock_init(&pch->downl);
         rwlock_init(&pch->upl);
-        spin_lock_bh(&all_channels_lock);
-        pch->file.index = ++last_channel_index;
-        list_add(&pch->list, &new_channels);
+
+        spin_lock_bh(&pn->all_channels_lock);
+        pch->file.index = ++pn->last_channel_index;
+        list_add(&pch->list, &pn->new_channels);
         atomic_inc(&channel_count);
-        spin_unlock_bh(&all_channels_lock);
+        spin_unlock_bh(&pn->all_channels_lock);
+
         return 0;
 }
 
@@ -2053,9 +2147,11 @@ void
 ppp_unregister_channel(struct ppp_channel *chan)
 {
         struct channel *pch = chan->ppp;
+        struct ppp_net *pn;
 
         if (!pch)
                 return;         /* should never happen */
+
         chan->ppp = NULL;
 
         /*
@@ -2068,9 +2164,12 @@ ppp_unregister_channel(struct ppp_channel *chan)
         spin_unlock_bh(&pch->downl);
         up_write(&pch->chan_sem);
         ppp_disconnect_channel(pch);
-        spin_lock_bh(&all_channels_lock);
+
+        pn = ppp_pernet(pch->chan_net);
+        spin_lock_bh(&pn->all_channels_lock);
         list_del(&pch->list);
-        spin_unlock_bh(&all_channels_lock);
+        spin_unlock_bh(&pn->all_channels_lock);
+
         pch->file.dead = 1;
         wake_up_interruptible(&pch->file.rwait);
         if (atomic_dec_and_test(&pch->file.refcnt))
@@ -2395,9 +2494,10 @@ ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
  * unit == -1 means allocate a new number.
  */
 static struct ppp *
-ppp_create_interface(int unit, int *retp)
+ppp_create_interface(struct net *net, int unit, int *retp)
 {
         struct ppp *ppp;
+        struct ppp_net *pn;
         struct net_device *dev = NULL;
         int ret = -ENOMEM;
         int i;
@@ -2406,6 +2506,8 @@ ppp_create_interface(int unit, int *retp)
         if (!dev)
                 goto out1;
 
+        pn = ppp_pernet(net);
+
         ppp = netdev_priv(dev);
         ppp->dev = dev;
         ppp->mru = PPP_MRU;
@@ -2421,17 +2523,23 @@ ppp_create_interface(int unit, int *retp)
         skb_queue_head_init(&ppp->mrq);
 #endif /* CONFIG_PPP_MULTILINK */
 
+        /*
+         * drum roll: don't forget to set
+         * the net device is belong to
+         */
+        dev_net_set(dev, net);
+
         ret = -EEXIST;
-        mutex_lock(&all_ppp_mutex);
+        mutex_lock(&pn->all_ppp_mutex);
 
         if (unit < 0) {
-                unit = unit_get(&ppp_units_idr, ppp);
+                unit = unit_get(&pn->units_idr, ppp);
                 if (unit < 0) {
                         *retp = unit;
                         goto out2;
                 }
         } else {
-                if (unit_find(&ppp_units_idr, unit))
+                if (unit_find(&pn->units_idr, unit))
                         goto out2; /* unit already exists */
                 /*
                  * if caller need a specified unit number
@@ -2442,7 +2550,7 @@ ppp_create_interface(int unit, int *retp)
                  * fair but at least pppd will ask us to allocate
                  * new unit in this case so user is happy :)
                  */
-                unit = unit_set(&ppp_units_idr, ppp, unit);
+                unit = unit_set(&pn->units_idr, ppp, unit);
                 if (unit < 0)
                         goto out2;
         }
@@ -2453,20 +2561,22 @@ ppp_create_interface(int unit, int *retp)
 
         ret = register_netdev(dev);
         if (ret != 0) {
-                unit_put(&ppp_units_idr, unit);
+                unit_put(&pn->units_idr, unit);
                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
                        dev->name, ret);
                 goto out2;
         }
 
+        ppp->ppp_net = net;
+
         atomic_inc(&ppp_unit_count);
-        mutex_unlock(&all_ppp_mutex);
+        mutex_unlock(&pn->all_ppp_mutex);
 
         *retp = 0;
         return ppp;
 
 out2:
-        mutex_unlock(&all_ppp_mutex);
+        mutex_unlock(&pn->all_ppp_mutex);
         free_netdev(dev);
 out1:
         *retp = ret;
@@ -2492,7 +2602,11 @@ init_ppp_file(struct ppp_file *pf, int kind)
  */
 static void ppp_shutdown_interface(struct ppp *ppp)
 {
-        mutex_lock(&all_ppp_mutex);
+        struct ppp_net *pn;
+
+        pn = ppp_pernet(ppp->ppp_net);
+        mutex_lock(&pn->all_ppp_mutex);
+
         /* This will call dev_close() for us. */
         ppp_lock(ppp);
         if (!ppp->closing) {
@@ -2502,11 +2616,12 @@ static void ppp_shutdown_interface(struct ppp *ppp)
         } else
                 ppp_unlock(ppp);
 
-        unit_put(&ppp_units_idr, ppp->file.index);
+        unit_put(&pn->units_idr, ppp->file.index);
         ppp->file.dead = 1;
         ppp->owner = NULL;
         wake_up_interruptible(&ppp->file.rwait);
-        mutex_unlock(&all_ppp_mutex);
+
+        mutex_unlock(&pn->all_ppp_mutex);
 }
 
 /*
@@ -2554,9 +2669,9 @@ static void ppp_destroy_interface(struct ppp *ppp)
  * The caller should have locked the all_ppp_mutex.
  */
 static struct ppp *
-ppp_find_unit(int unit)
+ppp_find_unit(struct ppp_net *pn, int unit)
 {
-        return unit_find(&ppp_units_idr, unit);
+        return unit_find(&pn->units_idr, unit);
 }
 
 /*
@@ -2568,20 +2683,22 @@ ppp_find_unit(int unit)
  * when we have a lot of channels in use.
  */
 static struct channel *
-ppp_find_channel(int unit)
+ppp_find_channel(struct ppp_net *pn, int unit)
 {
         struct channel *pch;
 
-        list_for_each_entry(pch, &new_channels, list) {
+        list_for_each_entry(pch, &pn->new_channels, list) {
                 if (pch->file.index == unit) {
-                        list_move(&pch->list, &all_channels);
+                        list_move(&pch->list, &pn->all_channels);
                         return pch;
                 }
         }
-        list_for_each_entry(pch, &all_channels, list) {
+
+        list_for_each_entry(pch, &pn->all_channels, list) {
                 if (pch->file.index == unit)
                         return pch;
         }
+
         return NULL;
 }
 
@@ -2592,11 +2709,14 @@ static int
 ppp_connect_channel(struct channel *pch, int unit)
 {
         struct ppp *ppp;
+        struct ppp_net *pn;
         int ret = -ENXIO;
         int hdrlen;
 
-        mutex_lock(&all_ppp_mutex);
-        ppp = ppp_find_unit(unit);
+        pn = ppp_pernet(pch->chan_net);
+
+        mutex_lock(&pn->all_ppp_mutex);
+        ppp = ppp_find_unit(pn, unit);
         if (!ppp)
                 goto out;
         write_lock_bh(&pch->upl);
@@ -2620,7 +2740,7 @@ ppp_connect_channel(struct channel *pch, int unit)
  outl:
         write_unlock_bh(&pch->upl);
  out:
-        mutex_unlock(&all_ppp_mutex);
+        mutex_unlock(&pn->all_ppp_mutex);
         return ret;
 }
 
@@ -2677,7 +2797,7 @@ static void __exit ppp_cleanup(void)
         unregister_chrdev(PPP_MAJOR, "ppp");
         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
         class_destroy(ppp_class);
-        idr_destroy(&ppp_units_idr);
+        unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
 }
 
 /*
@@ -2743,6 +2863,7 @@ static void *unit_find(struct idr *p, int n)
 module_init(ppp_init);
 module_exit(ppp_cleanup);
 
+EXPORT_SYMBOL(ppp_register_net_channel);
 EXPORT_SYMBOL(ppp_register_channel);
 EXPORT_SYMBOL(ppp_unregister_channel);
 EXPORT_SYMBOL(ppp_channel_index);
diff --git a/include/linux/ppp_channel.h b/include/linux/ppp_channel.h
index a942892d6dfe..9d64bdf14770 100644
--- a/include/linux/ppp_channel.h
+++ b/include/linux/ppp_channel.h
@@ -22,6 +22,7 @@
 #include <linux/list.h>
 #include <linux/skbuff.h>
 #include <linux/poll.h>
+#include <net/net_namespace.h>
 
 struct ppp_channel;
 
@@ -56,6 +57,9 @@ extern void ppp_input(struct ppp_channel *, struct sk_buff *);
    that we may have missed a packet. */
 extern void ppp_input_error(struct ppp_channel *, int code);
 
+/* Attach a channel to a given PPP unit in specified net. */
+extern int ppp_register_net_channel(struct net *, struct ppp_channel *);
+
 /* Attach a channel to a given PPP unit. */
 extern int ppp_register_channel(struct ppp_channel *);