Allow setting tun name in daemon config

AppDir/etc/daemon.yml

@@ -52,6 +52,10 @@ vpn:
 
       # That's it.
 
+  tun:
+    # Name of the tun network device which will route VPN traffic.
+    device: isle-tun
+
 storage:
 
   # Allocations defined here are used to store data in the distributed storage

default.nix

@@ -165,7 +165,7 @@ in rec {
   };
 
   tests = pkgs.writeShellScript "isle-tests" ''
-    export PATH=$PATH:${appImage}/bin
+    export PATH=${appImage}/bin:$PATH
     test_dir=${./tests}
     exec $SHELL $test_dir/entrypoint.sh "$@"
   '';

go/cmd/entrypoint/nebula_util.go

@@ -68,7 +68,7 @@ func nebulaPmuxProcConfig(
 			"respond": true,
 		},
 		"tun": map[string]interface{}{
-			"dev": "isle-tun",
+			"dev": daemonConfig.VPN.Tun.Device,
 		},
 		"firewall": daemonConfig.VPN.Firewall,
 	}

go/daemon/config.go

@@ -2,6 +2,10 @@ package daemon
 
 import "strconv"
 
+type ConfigTun struct {
+	Device string `yaml:"device"`
+}
+
 type ConfigFirewall struct {
 	Conntrack ConfigConntrack      `yaml:"conntrack"`
 	Outbound  []ConfigFirewallRule `yaml:"outbound"`
@@ -50,6 +54,7 @@ type Config struct {
 	VPN struct {
 		PublicAddr string         `yaml:"public_addr"`
 		Firewall   ConfigFirewall `yaml:"firewall"`
+		Tun        ConfigTun      `yaml:"tun"`
 	} `yaml:"vpn"`
 	Storage struct {
 		Allocations []ConfigStorageAllocation