Add route management for Android interface (#801)

Support client route management feature on Android

client/internal/routemanager/systemops.go

@@ -1,58 +0,0 @@
-package routemanager
-
-import (
-	"fmt"
-	"github.com/libp2p/go-netroute"
-	log "github.com/sirupsen/logrus"
-	"net"
-	"net/netip"
-)
-
-var errRouteNotFound = fmt.Errorf("route not found")
-
-func addToRouteTableIfNoExists(prefix netip.Prefix, addr string) error {
-	gateway, err := getExistingRIBRouteGateway(netip.MustParsePrefix("0.0.0.0/0"))
-	if err != nil && err != errRouteNotFound {
-		return err
-	}
-	prefixGateway, err := getExistingRIBRouteGateway(prefix)
-	if err != nil && err != errRouteNotFound {
-		return err
-	}
-
-	if prefixGateway != nil && !prefixGateway.Equal(gateway) {
-		log.Warnf("skipping adding a new route for network %s because it already exists and is pointing to the non default gateway: %s", prefix, prefixGateway)
-		return nil
-	}
-	return addToRouteTable(prefix, addr)
-}
-
-func removeFromRouteTableIfNonSystem(prefix netip.Prefix, addr string) error {
-	addrIP := net.ParseIP(addr)
-	prefixGateway, err := getExistingRIBRouteGateway(prefix)
-	if err != nil {
-		return err
-	}
-	if prefixGateway != nil && !prefixGateway.Equal(addrIP) {
-		log.Warnf("route for network %s is pointing to a different gateway: %s, should be pointing to: %s, not removing", prefix, prefixGateway, addrIP)
-		return nil
-	}
-	return removeFromRouteTable(prefix)
-}
-
-func getExistingRIBRouteGateway(prefix netip.Prefix) (net.IP, error) {
-	r, err := netroute.New()
-	if err != nil {
-		return nil, err
-	}
-	_, gateway, preferredSrc, err := r.Route(prefix.Addr().AsSlice())
-	if err != nil {
-		log.Errorf("getting routes returned an error: %v", err)
-		return nil, errRouteNotFound
-	}
-	if gateway == nil {
-		return preferredSrc, nil
-	}
-
-	return gateway, nil
-}