Subscribe for async updates on links and routes

link_linux.go

@@ -585,6 +585,46 @@ func LinkList() ([]Link, error) {
 	return res, nil
 }
 
+// LinkUpdate is used to pass information back from LinkSubscribe()
+type LinkUpdate struct {
+	nl.IfInfomsg
+	Link
+}
+
+// LinkSubscribe takes a chan down which notifications will be sent
+// when links change.  Close the 'done' chan to stop subscription.
+func LinkSubscribe(ch chan<- LinkUpdate, done <-chan struct{}) error {
+	s, err := nl.Subscribe(syscall.NETLINK_ROUTE, syscall.RTNLGRP_LINK)
+	if err != nil {
+		return err
+	}
+	if done != nil {
+		go func() {
+			<-done
+			s.Close()
+		}()
+	}
+	go func() {
+		defer close(ch)
+		for {
+			msgs, err := s.Receive()
+			if err != nil {
+				return
+			}
+			for _, m := range msgs {
+				ifmsg := nl.DeserializeIfInfomsg(m.Data)
+				link, err := linkDeserialize(m.Data)
+				if err != nil {
+					return
+				}
+				ch <- LinkUpdate{IfInfomsg: *ifmsg, Link: link}
+			}
+		}
+	}()
+
+	return nil
+}
+
 func LinkSetHairpin(link Link, mode bool) error {
 	return setProtinfoAttr(link, mode, nl.IFLA_BRPORT_MODE)
 }

route.go

@@ -33,3 +33,9 @@ func (r Route) String() string {
 	return fmt.Sprintf("{Ifindex: %d Dst: %s Src: %s Gw: %s}", r.LinkIndex, r.Dst,
 		r.Src, r.Gw)
 }
+
+// RouteUpdate is sent when a route changes - type is RTM_NEWROUTE or RTM_DELROUTE
+type RouteUpdate struct {
+	Type uint16
+	Route
+}

route_linux.go

@@ -214,3 +214,36 @@ func RouteGet(destination net.IP) ([]Route, error) {
 	return res, nil
 
 }
+
+// RouteSubscribe takes a chan down which notifications will be sent
+// when routes are added or deleted. Close the 'done' chan to stop subscription.
+func RouteSubscribe(ch chan<- RouteUpdate, done <-chan struct{}) error {
+	s, err := nl.Subscribe(syscall.NETLINK_ROUTE, syscall.RTNLGRP_IPV4_ROUTE, syscall.RTNLGRP_IPV6_ROUTE)
+	if err != nil {
+		return err
+	}
+	if done != nil {
+		go func() {
+			<-done
+			s.Close()
+		}()
+	}
+	go func() {
+		defer close(ch)
+		for {
+			msgs, err := s.Receive()
+			if err != nil {
+				return
+			}
+			for _, m := range msgs {
+				route, err := deserializeRoute(m.Data)
+				if err != nil {
+					return
+				}
+				ch <- RouteUpdate{Type: m.Header.Type, Route: route}
+			}
+		}
+	}()
+
+	return nil
+}