From d7a6caa2acd3422ce83cdb720539caee128d4202 Mon Sep 17 00:00:00 2001
From: "Quentin McGaw (desktop)" <quentin.mcgaw@gmail.com>
Date: Mon, 26 Jul 2021 16:18:53 +0000
Subject: [PATCH] Maint: routing interface composition

---
 cmd/gluetun/main.go                 |  2 +-
 internal/routing/enable.go          |  8 ++++++++
 internal/routing/outboundsubnets.go |  4 ++++
 internal/routing/reader.go          | 24 +++++++++++++++++++++++
 internal/routing/routing.go         | 30 +++++++++++++++++++----------
 5 files changed, 57 insertions(+), 11 deletions(-)

diff --git a/cmd/gluetun/main.go b/cmd/gluetun/main.go
index b5af2f0f..35a87e3d 100644
--- a/cmd/gluetun/main.go
+++ b/cmd/gluetun/main.go
@@ -449,7 +449,7 @@ func printVersions(ctx context.Context, logger logging.Logger,
 func routeReadyEvents(ctx context.Context, done chan<- struct{}, buildInfo models.BuildInformation,
 	tunnelReadyCh <-chan struct{},
 	unboundLooper dns.Looper, updaterLooper updater.Looper, publicIPLooper publicip.Looper,
-	routing routing.Routing, logger logging.Logger, httpClient *http.Client,
+	routing routing.VPNGetter, logger logging.Logger, httpClient *http.Client,
 	versionInformation, portForwardingEnabled bool, startPortForward func(vpnGateway net.IP)) {
 	defer close(done)
 
diff --git a/internal/routing/enable.go b/internal/routing/enable.go
index e46d9bac..5ef4b669 100644
--- a/internal/routing/enable.go
+++ b/internal/routing/enable.go
@@ -20,6 +20,10 @@ var (
 	ErrSubnetsOutboundSet = errors.New("cannot set outbound subnets routes")
 )
 
+type Setuper interface {
+	Setup() (err error)
+}
+
 func (r *routing) Setup() (err error) {
 	defaultIP, err := r.DefaultIP()
 	if err != nil {
@@ -59,6 +63,10 @@ func (r *routing) Setup() (err error) {
 	return nil
 }
 
+type TearDowner interface {
+	TearDown() error
+}
+
 func (r *routing) TearDown() error {
 	defaultIP, err := r.DefaultIP()
 	if err != nil {
diff --git a/internal/routing/outboundsubnets.go b/internal/routing/outboundsubnets.go
index c003e4cc..e14ebaea 100644
--- a/internal/routing/outboundsubnets.go
+++ b/internal/routing/outboundsubnets.go
@@ -10,6 +10,10 @@ var (
 	ErrAddOutboundSubnet = errors.New("cannot add outbound subnet to routes")
 )
 
+type OutboundRoutesSetter interface {
+	SetOutboundRoutes(outboundSubnets []net.IPNet) error
+}
+
 func (r *routing) SetOutboundRoutes(outboundSubnets []net.IPNet) error {
 	defaultInterface, defaultGateway, err := r.DefaultRoute()
 	if err != nil {
diff --git a/internal/routing/reader.go b/internal/routing/reader.go
index 5115385b..8d1f6308 100644
--- a/internal/routing/reader.go
+++ b/internal/routing/reader.go
@@ -34,6 +34,10 @@ var (
 	ErrVPNLocalGatewayIPNotFound = errors.New("VPN local gateway IP address not found")
 )
 
+type DefaultRouteGetter interface {
+	DefaultRoute() (defaultInterface string, defaultGateway net.IP, err error)
+}
+
 func (r *routing) DefaultRoute() (defaultInterface string, defaultGateway net.IP, err error) {
 	routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
 	if err != nil {
@@ -57,6 +61,10 @@ func (r *routing) DefaultRoute() (defaultInterface string, defaultGateway net.IP
 	return "", nil, fmt.Errorf("%w: in %d route(s)", ErrRouteDefaultNotFound, len(routes))
 }
 
+type DefaultIPGetter interface {
+	DefaultIP() (defaultIP net.IP, err error)
+}
+
 func (r *routing) DefaultIP() (ip net.IP, err error) {
 	routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
 	if err != nil {
@@ -81,6 +89,10 @@ func (r *routing) DefaultIP() (ip net.IP, err error) {
 	return r.assignedIP(defaultLinkName)
 }
 
+type LocalSubnetGetter interface {
+	LocalSubnet() (defaultSubnet net.IPNet, err error)
+}
+
 func (r *routing) LocalSubnet() (defaultSubnet net.IPNet, err error) {
 	routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
 	if err != nil {
@@ -110,6 +122,10 @@ func (r *routing) LocalSubnet() (defaultSubnet net.IPNet, err error) {
 	return defaultSubnet, fmt.Errorf("%w: in %d routes", ErrSubnetDefaultNotFound, len(routes))
 }
 
+type LocalNetworksGetter interface {
+	LocalNetworks() (localNetworks []LocalNetwork, err error)
+}
+
 func (r *routing) LocalNetworks() (localNetworks []LocalNetwork, err error) {
 	links, err := netlink.LinkList()
 	if err != nil {
@@ -193,6 +209,10 @@ func (r *routing) assignedIP(interfaceName string) (ip net.IP, err error) {
 		ErrInterfaceIPNotFound, interfaceName, len(addresses))
 }
 
+type VPNDestinationIPGetter interface {
+	VPNDestinationIP() (ip net.IP, err error)
+}
+
 func (r *routing) VPNDestinationIP() (ip net.IP, err error) {
 	routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
 	if err != nil {
@@ -221,6 +241,10 @@ func (r *routing) VPNDestinationIP() (ip net.IP, err error) {
 	return nil, fmt.Errorf("%w: in %d routes", ErrVPNDestinationIPNotFound, len(routes))
 }
 
+type VPNLocalGatewayIPGetter interface {
+	VPNLocalGatewayIP() (ip net.IP, err error)
+}
+
 func (r *routing) VPNLocalGatewayIP() (ip net.IP, err error) {
 	routes, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
 	if err != nil {
diff --git a/internal/routing/routing.go b/internal/routing/routing.go
index 7d331331..86246674 100644
--- a/internal/routing/routing.go
+++ b/internal/routing/routing.go
@@ -9,17 +9,27 @@ import (
 )
 
 type Routing interface {
-	// Mutations
-	Setup() (err error)
-	TearDown() error
-	SetOutboundRoutes(outboundSubnets []net.IPNet) error
+	Reader
+	Writer
+}
 
-	// Read only
-	DefaultRoute() (defaultInterface string, defaultGateway net.IP, err error)
-	LocalNetworks() (localNetworks []LocalNetwork, err error)
-	DefaultIP() (defaultIP net.IP, err error)
-	VPNDestinationIP() (ip net.IP, err error)
-	VPNLocalGatewayIP() (ip net.IP, err error)
+type Reader interface {
+	DefaultRouteGetter
+	DefaultIPGetter
+	LocalSubnetGetter
+	LocalNetworksGetter
+	VPNGetter
+}
+
+type VPNGetter interface {
+	VPNDestinationIPGetter
+	VPNLocalGatewayIPGetter
+}
+
+type Writer interface {
+	Setuper
+	TearDowner
+	OutboundRoutesSetter
 }
 
 type routing struct {