Add Route DB model and migration from existing field

Add migration from Machine.EnabledRoutes to the new Route table

Cleanup route.go and add helper methods to process HostInfo

db.go

@@ -18,8 +18,10 @@ import (
 )
 
 const (
-	dbVersion        = "1"
-	errValueNotFound = Error("not found")
+	dbVersion = "1"
+
+	errValueNotFound     = Error("not found")
+	ErrCannotParsePrefix = Error("cannot parse prefix")
 )
 
 // KV is a key-value store in a psql table. For future use...
@@ -79,6 +81,65 @@ func (h *Headscale) initDB() error {
 		}
 	}
 
+	err = db.AutoMigrate(&Route{})
+	if err != nil {
+		return err
+	}
+
+	if db.Migrator().HasColumn(&Machine{}, "enabled_routes") {
+		log.Info().Msgf("Database has legacy enabled_routes column in machine, migrating...")
+
+		type MachineAux struct {
+			ID            uint64
+			EnabledRoutes IPPrefixes
+		}
+
+		machinesAux := []MachineAux{}
+		err := db.Table("machines").Select("id, enabled_routes").Scan(&machinesAux).Error
+		if err != nil {
+			log.Fatal().Err(err).Msg("Error accessing db")
+		}
+		for _, machine := range machinesAux {
+			for _, prefix := range machine.EnabledRoutes {
+				if err != nil {
+					log.Error().
+						Err(err).
+						Str("enabled_route", prefix.String()).
+						Msg("Error parsing enabled_route")
+					continue
+				}
+
+				err = db.Preload("Machine").Where("machine_id = ? AND prefix = ?", machine.ID, IPPrefix(prefix)).First(&Route{}).Error
+				if err == nil {
+					log.Info().
+						Str("enabled_route", prefix.String()).
+						Msg("Route already migrated to new table, skipping")
+					continue
+				}
+
+				route := Route{
+					MachineID:  machine.ID,
+					Advertised: true,
+					Enabled:    true,
+					Prefix:     IPPrefix(prefix),
+				}
+				if err := h.db.Create(&route).Error; err != nil {
+					log.Error().Err(err).Msg("Error creating route")
+				} else {
+					log.Info().
+						Uint64("machine_id", route.MachineID).
+						Str("prefix", prefix.String()).
+						Msg("Route migrated")
+				}
+			}
+		}
+
+		err = db.Migrator().DropColumn(&Machine{}, "enabled_routes")
+		if err != nil {
+			log.Error().Err(err).Msg("Error dropping enabled_routes column")
+		}
+	}
+
 	err = db.AutoMigrate(&Machine{})
 	if err != nil {
 		return err
@@ -264,6 +325,28 @@ func (hi HostInfo) Value() (driver.Value, error) {
 	return string(bytes), err
 }
 
+type IPPrefix netip.Prefix
+
+func (i *IPPrefix) Scan(destination interface{}) error {
+	switch value := destination.(type) {
+	case string:
+		prefix, err := netip.ParsePrefix(value)
+		if err != nil {
+			return err
+		}
+		*i = IPPrefix(prefix)
+		return nil
+	default:
+		return fmt.Errorf("%w: unexpected data type %T", ErrCannotParsePrefix, destination)
+	}
+}
+
+// Value return json value, implement driver.Valuer interface.
+func (i IPPrefix) Value() (driver.Value, error) {
+	prefixStr := netip.Prefix(i).String()
+	return prefixStr, nil
+}
+
 type IPPrefixes []netip.Prefix
 
 func (i *IPPrefixes) Scan(destination interface{}) error {