tun: implement carrier change

The userspace may need to control the carrier state.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Didier Pallard <didier.pallard@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 56575f88d1fdbfdd790067a3b4631366990cd59a..835c73f42ae7a1153b285d77148b385aeca9b968 100644 (file)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1254,6 +1254,21 @@ static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
        }
 }
 
+static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
+{
+       if (new_carrier) {
+               struct tun_struct *tun = netdev_priv(dev);
+
+               if (!tun->numqueues)
+                       return -EPERM;
+
+               netif_carrier_on(dev);
+       } else {
+               netif_carrier_off(dev);
+       }
+       return 0;
+}
+
 static const struct net_device_ops tun_netdev_ops = {
        .ndo_uninit             = tun_net_uninit,
        .ndo_open               = tun_net_open,
@@ -1263,6 +1278,7 @@ static const struct net_device_ops tun_netdev_ops = {
        .ndo_select_queue       = tun_select_queue,
        .ndo_set_rx_headroom    = tun_set_headroom,
        .ndo_get_stats64        = tun_net_get_stats64,
+       .ndo_change_carrier     = tun_net_change_carrier,
 };
 
 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
@@ -1345,6 +1361,7 @@ static const struct net_device_ops tap_netdev_ops = {
        .ndo_get_stats64        = tun_net_get_stats64,
        .ndo_bpf                = tun_xdp,
        .ndo_xdp_xmit           = tun_xdp_xmit,
+       .ndo_change_carrier     = tun_net_change_carrier,
 };
 
 static void tun_flow_init(struct tun_struct *tun)
@@ -3002,12 +3019,12 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
        struct net *net = sock_net(&tfile->sk);
        struct tun_struct *tun;
        void __user* argp = (void __user*)arg;
+       unsigned int ifindex, carrier;
        struct ifreq ifr;
        kuid_t owner;
        kgid_t group;
        int sndbuf;
        int vnet_hdr_sz;
-       unsigned int ifindex;
        int le;
        int ret;
        bool do_notify = false;
@@ -3291,6 +3308,14 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
                ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
                break;
 
+       case TUNSETCARRIER:
+               ret = -EFAULT;
+               if (copy_from_user(&carrier, argp, sizeof(carrier)))
+                       goto unlock;
+
+               ret = tun_net_change_carrier(tun->dev, (bool)carrier);
+               break;
+
        default:
                ret = -EINVAL;
                break;

diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h
index ee432cd3018c595b2cc3d1346a4bb65c6aca5069..23a6753b37df3a0a241c2986aa932301bef02b1f 100644 (file)
--- a/include/uapi/linux/if_tun.h
+++ b/include/uapi/linux/if_tun.h
@@ -59,6 +59,7 @@
 #define TUNGETVNETBE _IOR('T', 223, int)
 #define TUNSETSTEERINGEBPF _IOR('T', 224, int)
 #define TUNSETFILTEREBPF _IOR('T', 225, int)
+#define TUNSETCARRIER _IOW('T', 226, int)
 
 /* TUNSETIFF ifr flags */
 #define IFF_TUN                0x0001