sysctl: Wireguard with fwmark requires udp_l3mdev_accept

Signed-off-by: Maximilian Wilhelm <max@sdn.clinic>

sysctl/global.conf

@@ -28,6 +28,7 @@ net.ipv4.icmp_errors_use_inbound_ifaddr = 1
 # derived from the listen socket to be bound to the L3 domain in
 # which the packets originated. Only valid when the kernel was
 # compiled with CONFIG_NET_L3_MASTER_DEV.
+net.ipv4.udp_l3mdev_accept = 1
 net.ipv4.tcp_l3mdev_accept = 1