From bf518c5fba3c12d6d6289e586596b591ba0f8051 Mon Sep 17 00:00:00 2001
From: Viktor Liu <17948409+lixmal@users.noreply.github.com>
Date: Tue, 2 Jul 2024 12:41:15 +0200
Subject: [PATCH] Remove interface network monitor checks (#2223)

---
 client/internal/networkmonitor/monitor_bsd.go | 36 -------------------
 .../internal/networkmonitor/monitor_linux.go  | 24 -------------
 2 files changed, 60 deletions(-)

diff --git a/client/internal/networkmonitor/monitor_bsd.go b/client/internal/networkmonitor/monitor_bsd.go
index 253fd68ff..8d6ccd51b 100644
--- a/client/internal/networkmonitor/monitor_bsd.go
+++ b/client/internal/networkmonitor/monitor_bsd.go
@@ -45,24 +45,6 @@ func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop, ca
 			msg := (*unix.RtMsghdr)(unsafe.Pointer(&buf[0]))
 
 			switch msg.Type {
-
-			// handle interface state changes
-			case unix.RTM_IFINFO:
-				ifinfo, err := parseInterfaceMessage(buf[:n])
-				if err != nil {
-					log.Errorf("Network monitor: error parsing interface message: %v", err)
-					continue
-				}
-				if msg.Flags&unix.IFF_UP != 0 {
-					continue
-				}
-				if (nexthopv4.Intf == nil || ifinfo.Index != nexthopv4.Intf.Index) && (nexthopv6.Intf == nil || ifinfo.Index != nexthopv6.Intf.Index) {
-					continue
-				}
-
-				log.Infof("Network monitor: monitored interface (%s) is down.", ifinfo.Name)
-				go callback()
-
 			// handle route changes
 			case unix.RTM_ADD, syscall.RTM_DELETE:
 				route, err := parseRouteMessage(buf[:n])
@@ -94,24 +76,6 @@ func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop, ca
 	}
 }
 
-func parseInterfaceMessage(buf []byte) (*route.InterfaceMessage, error) {
-	msgs, err := route.ParseRIB(route.RIBTypeInterface, buf)
-	if err != nil {
-		return nil, fmt.Errorf("parse RIB: %v", err)
-	}
-
-	if len(msgs) != 1 {
-		return nil, fmt.Errorf("unexpected RIB message msgs: %v", msgs)
-	}
-
-	msg, ok := msgs[0].(*route.InterfaceMessage)
-	if !ok {
-		return nil, fmt.Errorf("unexpected RIB message type: %T", msgs[0])
-	}
-
-	return msg, nil
-}
-
 func parseRouteMessage(buf []byte) (*systemops.Route, error) {
 	msgs, err := route.ParseRIB(route.RIBTypeRoute, buf)
 	if err != nil {
diff --git a/client/internal/networkmonitor/monitor_linux.go b/client/internal/networkmonitor/monitor_linux.go
index de5e29b38..035be1f09 100644
--- a/client/internal/networkmonitor/monitor_linux.go
+++ b/client/internal/networkmonitor/monitor_linux.go
@@ -19,14 +19,9 @@ func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop, ca
 		return errors.New("no interfaces available")
 	}
 
-	linkChan := make(chan netlink.LinkUpdate)
 	done := make(chan struct{})
 	defer close(done)
 
-	if err := netlink.LinkSubscribe(linkChan, done); err != nil {
-		return fmt.Errorf("subscribe to link updates: %v", err)
-	}
-
 	routeChan := make(chan netlink.RouteUpdate)
 	if err := netlink.RouteSubscribe(routeChan, done); err != nil {
 		return fmt.Errorf("subscribe to route updates: %v", err)
@@ -38,25 +33,6 @@ func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop, ca
 		case <-ctx.Done():
 			return ErrStopped
 
-		// handle interface state changes
-		case update := <-linkChan:
-			if (nexthopv4.Intf == nil || update.Index != int32(nexthopv4.Intf.Index)) && (nexthopv6.Intf == nil || update.Index != int32(nexthopv6.Intf.Index)) {
-				continue
-			}
-
-			switch update.Header.Type {
-			case syscall.RTM_DELLINK:
-				log.Infof("Network monitor: monitored interface (%s) is gone", update.Link.Attrs().Name)
-				go callback()
-				return nil
-			case syscall.RTM_NEWLINK:
-				if (update.IfInfomsg.Flags&syscall.IFF_RUNNING) == 0 && update.Link.Attrs().OperState == netlink.OperDown {
-					log.Infof("Network monitor: monitored interface (%s) is down.", update.Link.Attrs().Name)
-					go callback()
-					return nil
-				}
-			}
-
 		// handle route changes
 		case route := <-routeChan:
 			// default route and main table