[PATCH v3 06/12] device: store a copy of the device net

[Julian Orth]

This eliminates the need for have_transit_net_ref because
have_transit_net_ref == true if and only if dev_net != transit_net.
---
 src/device.c | 27 +++++++++++++++++----------
 src/device.h |  4 +++-
 2 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/src/device.c b/src/device.c
index 92aefc4..71c0662 100644
--- a/src/device.c
+++ b/src/device.c
@@ -243,7 +243,7 @@ static void destruct(struct net_device *dev)
        skb_queue_purge(&wg->incoming_handshakes);
        free_percpu(dev->tstats);
        free_percpu(wg->incoming_handshakes_worker);
-       if (wg->have_transit_net_ref)
+       if (wg->transit_net != wg->dev_net)
                put_net(wg->transit_net);
        mutex_unlock(&wg->device_update_lock);
 
@@ -296,7 +296,9 @@ static int newlink(struct net *src_net, struct net_device 
*dev,
        int ret = -ENOMEM;
        struct wireguard_device *wg = netdev_priv(dev);
 
-       wg->transit_net = src_net;
+       wg->dev_net = NULL;
+       wg->transit_net = NULL;
+       device_set_nets(wg,  dev_net(dev), src_net);
        init_rwsem(&wg->static_identity.lock);
        mutex_init(&wg->socket_update_lock);
        mutex_init(&wg->device_update_lock);
@@ -396,14 +398,8 @@ static int netdevice_notification(struct notifier_block 
*nb,
        if (action != NETDEV_REGISTER || dev->netdev_ops != &netdev_ops)
                return 0;
 
-       if (dev_net(dev) == wg->transit_net && wg->have_transit_net_ref) {
-               put_net(wg->transit_net);
-               wg->have_transit_net_ref = false;
-       } else if (dev_net(dev) != wg->transit_net &&
-                  !wg->have_transit_net_ref) {
-               wg->have_transit_net_ref = true;
-               get_net(wg->transit_net);
-       }
+       device_set_nets(wg, dev_net(dev), wg->transit_net);
+
        return 0;
 }
 
@@ -449,3 +445,14 @@ void device_uninit(void)
 #endif
        rcu_barrier_bh();
 }
+
+void device_set_nets(struct wireguard_device *wg, struct net *dev_net,
+                    struct net *transit_net)
+{
+       if (wg->transit_net != wg->dev_net)
+               put_net(wg->transit_net);
+       wg->dev_net = dev_net;
+       wg->transit_net = transit_net;
+       if (wg->transit_net != wg->dev_net)
+               get_net(wg->transit_net);
+}
diff --git a/src/device.h b/src/device.h
index 4b7552c..eb229df 100644
--- a/src/device.h
+++ b/src/device.h
@@ -41,6 +41,7 @@ struct wireguard_device {
        struct crypt_queue encrypt_queue, decrypt_queue;
        struct sock __rcu *sock4, *sock6;
        struct net *transit_net;
+       struct net *dev_net;
        struct noise_static_identity static_identity;
        struct workqueue_struct *handshake_receive_wq, *handshake_send_wq;
        struct workqueue_struct *packet_crypt_wq;
@@ -56,10 +57,11 @@ struct wireguard_device {
        unsigned int num_peers, device_update_gen;
        u32 fwmark;
        u16 incoming_port;
-       bool have_transit_net_ref;
 };
 
 int device_init(void);
 void device_uninit(void);
+void device_set_nets(struct wireguard_device *wg, struct net *dev_net,
+                    struct net *transit_net);
 
 #endif /* _WG_DEVICE_H */
-- 
2.18.0

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