[NET]: Make the loopback device per network namespace.

This patch makes loopback_dev per network namespace.  Adding
code to create a different loopback device for each network
namespace and adding the code to free a loopback device
when a network namespace exits.

This patch modifies all users the loopback_dev so they
access it as init_net.loopback_dev, keeping all of the
code compiling and working.  A later pass will be needed to
update the users to use something other than the initial network
namespace.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

13 files changed, 64 insertions, 45 deletions

diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index f3018bb7570d..0f9d8c60c964 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -57,6 +57,7 @@
 #include <linux/ip.h>
 #include <linux/tcp.h>
 #include <linux/percpu.h>
+#include <net/net_namespace.h>
 
 struct pcpu_lstats {
         unsigned long packets;
@@ -252,7 +253,7 @@ static void loopback_setup(struct net_device *dev)
 }
 
 /* Setup and register the loopback device. */
-static int __init loopback_init(void)
+static int loopback_net_init(struct net *net)
 {
         struct net_device *dev;
         int err;
@@ -262,12 +263,13 @@ static int __init loopback_init(void)
         if (!dev)
                 goto out;
 
+        dev->nd_net = net;
         err = register_netdev(dev);
         if (err)
                 goto out_free_netdev;
 
         err = 0;
-        loopback_dev = dev;
+        net->loopback_dev = dev;
 
 out:
         if (err)
@@ -279,7 +281,21 @@ out_free_netdev:
         goto out;
 }
 
-fs_initcall(loopback_init);
+static void loopback_net_exit(struct net *net)
+{
+        struct net_device *dev = net->loopback_dev;
+
+        unregister_netdev(dev);
+}
+
+static struct pernet_operations loopback_net_ops = {
+       .init = loopback_net_init,
+       .exit = loopback_net_exit,
+};
+
+static int __init loopback_init(void)
+{
+        return register_pernet_device(&loopback_net_ops);
+}
 
-struct net_device *loopback_dev;
-EXPORT_SYMBOL(loopback_dev);
+fs_initcall(loopback_init);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 2088097663b5..71cf409ad17e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -742,7 +742,6 @@ struct packet_type {
 #include <linux/interrupt.h>
 #include <linux/notifier.h>
 
-extern struct net_device                *loopback_dev;          /* The loopback */
 extern rwlock_t                         dev_base_lock;          /* Device list lock */
 
 
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 3ea4194613ed..13b0e3b547f0 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -9,6 +9,7 @@
 #include <linux/list.h>
 
 struct proc_dir_entry;
+struct net_device;
 struct net {
         atomic_t                count;          /* To decided when the network
                                                  *  namespace should be freed.
@@ -23,6 +24,8 @@ struct net {
         struct proc_dir_entry   *proc_net_stat;
         struct proc_dir_entry   *proc_net_root;
 
+        struct net_device       *loopback_dev;          /* The loopback */
+
         struct list_head        dev_base_head;
         struct hlist_head       *dev_name_head;
         struct hlist_head       *dev_index_head;
diff --git a/net/core/dst.c b/net/core/dst.c
index ad5ffa19d809..16958e64e577 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -18,6 +18,7 @@
 #include <linux/types.h>
 #include <net/net_namespace.h>
 
+#include <net/net_namespace.h>
 #include <net/dst.h>
 
 /*
@@ -278,11 +279,11 @@ static inline void dst_ifdown(struct dst_entry *dst, struct net_device *dev,
         if (!unregister) {
                 dst->input = dst->output = dst_discard;
         } else {
-                dst->dev = loopback_dev;
+                dst->dev = init_net.loopback_dev;
                 dev_hold(dst->dev);
                 dev_put(dev);
                 if (dst->neighbour && dst->neighbour->dev == dev) {
-                        dst->neighbour->dev = loopback_dev;
+                        dst->neighbour->dev = init_net.loopback_dev;
                         dev_put(dev);
                         dev_hold(dst->neighbour->dev);
                 }
diff --git a/net/decnet/dn_dev.c b/net/decnet/dn_dev.c
index bcaf4c5aa68e..26130afd8029 100644
--- a/net/decnet/dn_dev.c
+++ b/net/decnet/dn_dev.c
@@ -869,10 +869,10 @@ last_chance:
                 rv = dn_dev_get_first(dev, addr);
                 read_unlock(&dev_base_lock);
                 dev_put(dev);
-                if (rv == 0 || dev == loopback_dev)
+                if (rv == 0 || dev == init_net.loopback_dev)
                         return rv;
         }
-        dev = loopback_dev;
+        dev = init_net.loopback_dev;
         dev_hold(dev);
         goto last_chance;
 }
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 96fe0aa1638e..b7ebf9947ebd 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -887,7 +887,7 @@ static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *old
                                         .scope = RT_SCOPE_UNIVERSE,
                                      } },
                             .mark = oldflp->mark,
-                            .iif = loopback_dev->ifindex,
+                            .iif = init_net.loopback_dev->ifindex,
                             .oif = oldflp->oif };
         struct dn_route *rt = NULL;
         struct net_device *dev_out = NULL, *dev;
@@ -904,7 +904,7 @@ static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *old
                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
                        " iif=%d oif=%d\n", dn_ntohs(oldflp->fld_dst),
                        dn_ntohs(oldflp->fld_src),
-                       oldflp->mark, loopback_dev->ifindex, oldflp->oif);
+                       oldflp->mark, init_net.loopback_dev->ifindex, oldflp->oif);
 
         /* If we have an output interface, verify its a DECnet device */
         if (oldflp->oif) {
@@ -957,7 +957,7 @@ source_ok:
                 err = -EADDRNOTAVAIL;
                 if (dev_out)
                         dev_put(dev_out);
-                dev_out = loopback_dev;
+                dev_out = init_net.loopback_dev;
                 dev_hold(dev_out);
                 if (!fl.fld_dst) {
                         fl.fld_dst =
@@ -966,7 +966,7 @@ source_ok:
                         if (!fl.fld_dst)
                                 goto out;
                 }
-                fl.oif = loopback_dev->ifindex;
+                fl.oif = init_net.loopback_dev->ifindex;
                 res.type = RTN_LOCAL;
                 goto make_route;
         }
@@ -1012,7 +1012,7 @@ source_ok:
                                         if (dev_out)
                                                 dev_put(dev_out);
                                         if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
-                                                dev_out = loopback_dev;
+                                                dev_out = init_net.loopback_dev;
                                                 res.type = RTN_LOCAL;
                                         } else {
                                                 dev_out = neigh->dev;
@@ -1033,7 +1033,7 @@ source_ok:
                 /* Possible improvement - check all devices for local addr */
                 if (dn_dev_islocal(dev_out, fl.fld_dst)) {
                         dev_put(dev_out);
-                        dev_out = loopback_dev;
+                        dev_out = init_net.loopback_dev;
                         dev_hold(dev_out);
                         res.type = RTN_LOCAL;
                         goto select_source;
@@ -1069,7 +1069,7 @@ select_source:
                         fl.fld_src = fl.fld_dst;
                 if (dev_out)
                         dev_put(dev_out);
-                dev_out = loopback_dev;
+                dev_out = init_net.loopback_dev;
                 dev_hold(dev_out);
                 fl.oif = dev_out->ifindex;
                 if (res.fi)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index ca2878dc6188..2a9b363e820c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1402,8 +1402,8 @@ static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 {
         struct rtable *rt = (struct rtable *) dst;
         struct in_device *idev = rt->idev;
-        if (dev != loopback_dev && idev && idev->dev == dev) {
-                struct in_device *loopback_idev = in_dev_get(loopback_dev);
+        if (dev != init_net.loopback_dev && idev && idev->dev == dev) {
+                struct in_device *loopback_idev = in_dev_get(init_net.loopback_dev);
                 if (loopback_idev) {
                         rt->idev = loopback_idev;
                         in_dev_put(idev);
@@ -1555,7 +1555,7 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 #endif
         rth->rt_iif     =
         rth->fl.iif     = dev->ifindex;
-        rth->u.dst.dev  = loopback_dev;
+        rth->u.dst.dev  = init_net.loopback_dev;
         dev_hold(rth->u.dst.dev);
         rth->idev       = in_dev_get(rth->u.dst.dev);
         rth->fl.oif     = 0;
@@ -1812,7 +1812,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
         if (res.type == RTN_LOCAL) {
                 int result;
                 result = fib_validate_source(saddr, daddr, tos,
-                                             loopback_dev->ifindex,
+                                             init_net.loopback_dev->ifindex,
                                              dev, &spec_dst, &itag);
                 if (result < 0)
                         goto martian_source;
@@ -1879,7 +1879,7 @@ local_input:
 #endif
         rth->rt_iif     =
         rth->fl.iif     = dev->ifindex;
-        rth->u.dst.dev  = loopback_dev;
+        rth->u.dst.dev  = init_net.loopback_dev;
         dev_hold(rth->u.dst.dev);
         rth->idev       = in_dev_get(rth->u.dst.dev);
         rth->rt_gateway = daddr;
@@ -2149,7 +2149,7 @@ static int ip_route_output_slow(struct rtable **rp, const struct flowi *oldflp)
                                                   RT_SCOPE_UNIVERSE),
                                       } },
                             .mark = oldflp->mark,
-                            .iif = loopback_dev->ifindex,
+                            .iif = init_net.loopback_dev->ifindex,
                             .oif = oldflp->oif };
         struct fib_result res;
         unsigned flags = 0;
@@ -2243,9 +2243,9 @@ static int ip_route_output_slow(struct rtable **rp, const struct flowi *oldflp)
                         fl.fl4_dst = fl.fl4_src = htonl(INADDR_LOOPBACK);
                 if (dev_out)
                         dev_put(dev_out);
-                dev_out = loopback_dev;
+                dev_out = init_net.loopback_dev;
                 dev_hold(dev_out);
-                fl.oif = loopback_dev->ifindex;
+                fl.oif = init_net.loopback_dev->ifindex;
                 res.type = RTN_LOCAL;
                 flags |= RTCF_LOCAL;
                 goto make_route;
@@ -2290,7 +2290,7 @@ static int ip_route_output_slow(struct rtable **rp, const struct flowi *oldflp)
                         fl.fl4_src = fl.fl4_dst;
                 if (dev_out)
                         dev_put(dev_out);
-                dev_out = loopback_dev;
+                dev_out = init_net.loopback_dev;
                 dev_hold(dev_out);
                 fl.oif = dev_out->ifindex;
                 if (res.fi)
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 29ab3de8c47f..329825ca68fe 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -306,7 +306,7 @@ static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 
         xdst = (struct xfrm_dst *)dst;
         if (xdst->u.rt.idev->dev == dev) {
-                struct in_device *loopback_idev = in_dev_get(loopback_dev);
+                struct in_device *loopback_idev = in_dev_get(init_net.loopback_dev);
                 BUG_ON(!loopback_idev);
 
                 do {
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index b43574f73375..6d5c3c299148 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2410,7 +2410,7 @@ static int addrconf_ifdown(struct net_device *dev, int how)
 
         ASSERT_RTNL();
 
-        if (dev == loopback_dev && how == 1)
+        if (dev == init_net.loopback_dev && how == 1)
                 how = 0;
 
         rt6_ifdown(dev);
@@ -4212,19 +4212,19 @@ int __init addrconf_init(void)
          * device and it being up should be removed.
          */
         rtnl_lock();
-        if (!ipv6_add_dev(loopback_dev))
+        if (!ipv6_add_dev(init_net.loopback_dev))
                 err = -ENOMEM;
         rtnl_unlock();
         if (err)
                 return err;
 
-        ip6_null_entry.u.dst.dev = loopback_dev;
-        ip6_null_entry.rt6i_idev = in6_dev_get(loopback_dev);
+        ip6_null_entry.u.dst.dev = init_net.loopback_dev;
+        ip6_null_entry.rt6i_idev = in6_dev_get(init_net.loopback_dev);
 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
-        ip6_prohibit_entry.u.dst.dev = loopback_dev;
-        ip6_prohibit_entry.rt6i_idev = in6_dev_get(loopback_dev);
-        ip6_blk_hole_entry.u.dst.dev = loopback_dev;
-        ip6_blk_hole_entry.rt6i_idev = in6_dev_get(loopback_dev);
+        ip6_prohibit_entry.u.dst.dev = init_net.loopback_dev;
+        ip6_prohibit_entry.rt6i_idev = in6_dev_get(init_net.loopback_dev);
+        ip6_blk_hole_entry.u.dst.dev = init_net.loopback_dev;
+        ip6_blk_hole_entry.rt6i_idev = in6_dev_get(init_net.loopback_dev);
 #endif
 
         register_netdevice_notifier(&ipv6_dev_notf);
@@ -4279,7 +4279,7 @@ void __exit addrconf_cleanup(void)
                         continue;
                 addrconf_ifdown(dev, 1);
         }
-        addrconf_ifdown(loopback_dev, 2);
+        addrconf_ifdown(init_net.loopback_dev, 2);
 
         /*
          *      Check hash table.
diff --git a/net/ipv6/netfilter/ip6t_REJECT.c b/net/ipv6/netfilter/ip6t_REJECT.c
index 50860531cd3c..3fd08d5567a6 100644
--- a/net/ipv6/netfilter/ip6t_REJECT.c
+++ b/net/ipv6/netfilter/ip6t_REJECT.c
@@ -167,7 +167,7 @@ static inline void
 send_unreach(struct sk_buff *skb_in, unsigned char code, unsigned int hooknum)
 {
         if (hooknum == NF_IP6_LOCAL_OUT && skb_in->dev == NULL)
-                skb_in->dev = loopback_dev;
+                skb_in->dev = init_net.loopback_dev;
 
         icmpv6_send(skb_in, ICMPV6_DEST_UNREACH, code, 0, NULL);
 }
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index a7a21a7ba790..6ff19f9eb9ee 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -221,8 +221,8 @@ static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
         struct rt6_info *rt = (struct rt6_info *)dst;
         struct inet6_dev *idev = rt->rt6i_idev;
 
-        if (dev != loopback_dev && idev != NULL && idev->dev == dev) {
-                struct inet6_dev *loopback_idev = in6_dev_get(loopback_dev);
+        if (dev != init_net.loopback_dev && idev != NULL && idev->dev == dev) {
+                struct inet6_dev *loopback_idev = in6_dev_get(init_net.loopback_dev);
                 if (loopback_idev != NULL) {
                         rt->rt6i_idev = loopback_idev;
                         in6_dev_put(idev);
@@ -1185,12 +1185,12 @@ int ip6_route_add(struct fib6_config *cfg)
         if ((cfg->fc_flags & RTF_REJECT) ||
             (dev && (dev->flags&IFF_LOOPBACK) && !(addr_type&IPV6_ADDR_LOOPBACK))) {
                 /* hold loopback dev/idev if we haven't done so. */
-                if (dev != loopback_dev) {
+                if (dev != init_net.loopback_dev) {
                         if (dev) {
                                 dev_put(dev);
                                 in6_dev_put(idev);
                         }
-                        dev = loopback_dev;
+                        dev = init_net.loopback_dev;
                         dev_hold(dev);
                         idev = in6_dev_get(dev);
                         if (!idev) {
@@ -1894,13 +1894,13 @@ struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
         if (rt == NULL)
                 return ERR_PTR(-ENOMEM);
 
-        dev_hold(loopback_dev);
+        dev_hold(init_net.loopback_dev);
         in6_dev_hold(idev);
 
         rt->u.dst.flags = DST_HOST;
         rt->u.dst.input = ip6_input;
         rt->u.dst.output = ip6_output;
-        rt->rt6i_dev = loopback_dev;
+        rt->rt6i_dev = init_net.loopback_dev;
         rt->rt6i_idev = idev;
         rt->u.dst.metrics[RTAX_MTU-1] = ipv6_get_mtu(rt->rt6i_dev);
         rt->u.dst.metrics[RTAX_ADVMSS-1] = ipv6_advmss(dst_mtu(&rt->u.dst));
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index cc07216cfd59..15aa4c58c315 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -375,7 +375,7 @@ static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 
         xdst = (struct xfrm_dst *)dst;
         if (xdst->u.rt6.rt6i_idev->dev == dev) {
-                struct inet6_dev *loopback_idev = in6_dev_get(loopback_dev);
+                struct inet6_dev *loopback_idev = in6_dev_get(init_net.loopback_dev);
                 BUG_ON(!loopback_idev);
 
                 do {
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index d6dfd7d1948f..76f172f13f90 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1949,7 +1949,7 @@ static int stale_bundle(struct dst_entry *dst)
 void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev)
 {
         while ((dst = dst->child) && dst->xfrm && dst->dev == dev) {
-                dst->dev = loopback_dev;
+                dst->dev = init_net.loopback_dev;
                 dev_hold(dst->dev);
                 dev_put(dev);
         }