Split code into modules

This is a massive commit that restructures the code into modules:

db/
    All functions related to modifying the Database

types/
    All type definitions and methods that can be exclusivly used on
    these types without dependencies

policy/
    All Policy related code, now without dependencies on the Database.

policy/matcher/
    Dedicated code to match machines in a list of FilterRules

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

cmd/headscale/cli/routes.go

@@ -7,7 +7,7 @@ import (
 	"strconv"
 
 	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
-	"github.com/juanfont/headscale/hscontrol"
+	"github.com/juanfont/headscale/hscontrol/types"
 	"github.com/pterm/pterm"
 	"github.com/spf13/cobra"
 	"google.golang.org/grpc/status"
@@ -277,7 +277,7 @@ func routesToPtables(routes []*v1.Route) pterm.TableData {
 
 			continue
 		}
-		if prefix == hscontrol.ExitRouteV4 || prefix == hscontrol.ExitRouteV6 {
+		if prefix == types.ExitRouteV4 || prefix == types.ExitRouteV6 {
 			isPrimaryStr = "-"
 		} else {
 			isPrimaryStr = strconv.FormatBool(route.IsPrimary)

cmd/headscale/cli/utils.go

@@ -10,6 +10,7 @@ import (
 
 	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
 	"github.com/juanfont/headscale/hscontrol"
+	"github.com/juanfont/headscale/hscontrol/policy"
 	"github.com/juanfont/headscale/hscontrol/util"
 	"github.com/rs/zerolog/log"
 	"google.golang.org/grpc"
@@ -41,13 +42,15 @@ func getHeadscaleApp() (*hscontrol.Headscale, error) {
 
 	if cfg.ACL.PolicyPath != "" {
 		aclPath := util.AbsolutePathFromConfigPath(cfg.ACL.PolicyPath)
-		err = app.LoadACLPolicyFromPath(aclPath)
+		pol, err := policy.LoadACLPolicyFromPath(aclPath)
 		if err != nil {
 			log.Fatal().
 				Str("path", aclPath).
 				Err(err).
 				Msg("Could not load the ACL policy")
 		}
+
+		app.ACLPolicy = pol
 	}
 
 	return app, nil