xfrm interface: fix management of phydev

With the current implementation, phydev cannot be removed:

$ ip link add dummy type dummy
$ ip link add xfrm1 type xfrm dev dummy if_id 1
$ ip l d dummy
 kernel:[77938.465445] unregister_netdevice: waiting for dummy to become free. Usage count = 1

Manage it like in ip tunnels, ie just keep the ifindex. Not that the side
effect, is that the phydev is now optional.

Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Tested-by: Julien Floret <julien.floret@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

2 files changed, 17 insertions, 16 deletions

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index ad761ef84797..aa08a7a5f6ac 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -990,7 +990,6 @@ struct xfrm_if_parms {
 struct xfrm_if {
         struct xfrm_if __rcu *next;     /* next interface in list */
         struct net_device *dev;         /* virtual device associated with interface */
-        struct net_device *phydev;      /* physical device */
         struct net *net;                /* netns for packet i/o */
         struct xfrm_if_parms p;         /* interface parms */
 
diff --git a/net/xfrm/xfrm_interface.c b/net/xfrm/xfrm_interface.c
index 53e5e47b2c55..2ab4859df55a 100644
--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -175,7 +175,6 @@ static void xfrmi_dev_uninit(struct net_device *dev)
         struct xfrmi_net *xfrmn = net_generic(xi->net, xfrmi_net_id);
 
         xfrmi_unlink(xfrmn, xi);
-        dev_put(xi->phydev);
         dev_put(dev);
 }
 
@@ -362,7 +361,7 @@ static netdev_tx_t xfrmi_xmit(struct sk_buff *skb, struct net_device *dev)
                 goto tx_err;
         }
 
-        fl.flowi_oif = xi->phydev->ifindex;
+        fl.flowi_oif = xi->p.link;
 
         ret = xfrmi_xmit2(skb, dev, &fl);
         if (ret < 0)
@@ -548,7 +547,7 @@ static int xfrmi_get_iflink(const struct net_device *dev)
 {
         struct xfrm_if *xi = netdev_priv(dev);
 
-        return xi->phydev->ifindex;
+        return xi->p.link;
 }
 
 
@@ -574,12 +573,14 @@ static void xfrmi_dev_setup(struct net_device *dev)
         dev->needs_free_netdev  = true;
         dev->priv_destructor    = xfrmi_dev_free;
         netif_keep_dst(dev);
+
+        eth_broadcast_addr(dev->broadcast);
 }
 
 static int xfrmi_dev_init(struct net_device *dev)
 {
         struct xfrm_if *xi = netdev_priv(dev);
-        struct net_device *phydev = xi->phydev;
+        struct net_device *phydev = __dev_get_by_index(xi->net, xi->p.link);
         int err;
 
         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
@@ -594,13 +595,19 @@ static int xfrmi_dev_init(struct net_device *dev)
 
         dev->features |= NETIF_F_LLTX;
 
-        dev->needed_headroom = phydev->needed_headroom;
-        dev->needed_tailroom = phydev->needed_tailroom;
+        if (phydev) {
+                dev->needed_headroom = phydev->needed_headroom;
+                dev->needed_tailroom = phydev->needed_tailroom;
 
-        if (is_zero_ether_addr(dev->dev_addr))
-                eth_hw_addr_inherit(dev, phydev);
-        if (is_zero_ether_addr(dev->broadcast))
-                memcpy(dev->broadcast, phydev->broadcast, dev->addr_len);
+                if (is_zero_ether_addr(dev->dev_addr))
+                        eth_hw_addr_inherit(dev, phydev);
+                if (is_zero_ether_addr(dev->broadcast))
+                        memcpy(dev->broadcast, phydev->broadcast,
+                               dev->addr_len);
+        } else {
+                eth_hw_addr_random(dev);
+                eth_broadcast_addr(dev->broadcast);
+        }
 
         return 0;
 }
@@ -644,13 +651,8 @@ static int xfrmi_newlink(struct net *src_net, struct net_device *dev,
         xi->p = p;
         xi->net = net;
         xi->dev = dev;
-        xi->phydev = dev_get_by_index(net, p.link);
-        if (!xi->phydev)
-                return -ENODEV;
 
         err = xfrmi_create(dev);
-        if (err < 0)
-                dev_put(xi->phydev);
         return err;
 }