// Wait for an interface to come up and have a route added to the multicast subnet.
// This matches the behaviour in 'weave attach', which is the only context in which
// we expect this to be called. If you change one, change the other to match.
func EnsureInterfaceAndMcastRoute(ifaceName string) (*net.Interface, error) {
iface, err := ensureInterface(ifaceName)
if err != nil {
return nil, err
}
ch := make(chan netlink.RouteUpdate)
done := make(chan struct{})
defer close(done)
if err := netlink.RouteSubscribe(ch, done); err != nil {
return nil, err
}
dest := net.IPv4(224, 0, 0, 0)
check := func(route netlink.Route) bool {
return route.LinkIndex == iface.Index && route.Dst != nil && route.Dst.IP.Equal(dest)
}
// check for currently-existing route after subscribing, to avoid race
routes, err := netlink.RouteList(nil, netlink.FAMILY_V4)
if err != nil {
return nil, err
}
for _, route := range routes {
if check(route) {
return iface, nil
}
}
for update := range ch {
if check(update.Route) {
return iface, nil
}
}
// should never get here
return iface, nil
}
// Wait for an interface to come up and have a route added to the multicast subnet.
// This matches the behaviour in 'weave attach', which is the only context in which
// we expect this to be called. If you change one, change the other to match.
func EnsureInterfaceAndMcastRoute(ifaceName string) (*net.Interface, error) {
iface, err := ensureInterface(ifaceName)
if err != nil {
return nil, err
}
dest := net.IPv4(224, 0, 0, 0)
if CheckRouteExists(ifaceName, dest) {
return iface, err
}
ch := make(chan netlink.RouteUpdate)
done := make(chan struct{})
defer close(done)
if err := netlink.RouteSubscribe(ch, done); err != nil {
return nil, err
}
for update := range ch {
link, _ := netlink.LinkByIndex(update.Route.LinkIndex)
if link.Attrs().Name == ifaceName && update.Route.Dst.IP.Equal(dest) {
break
}
}
return iface, nil
}
// This function should be put into the main process or somewhere that can be
// use to init the network namespace trap.
func setupNetworkNsTrap(netNs2Containerd func(supervisor.NetlinkUpdate)) {
// Subscribe for links change event
chLink := make(chan netlink.LinkUpdate)
doneLink := make(chan struct{})
defer close(doneLink)
if err := netlink.LinkSubscribe(chLink, doneLink); err != nil {
glog.Fatal(err)
}
// Subscribe for addresses change event
chAddr := make(chan netlink.AddrUpdate)
doneAddr := make(chan struct{})
defer close(doneAddr)
if err := netlink.AddrSubscribe(chAddr, doneAddr); err != nil {
glog.Fatal(err)
}
// Subscribe for route change event
chRoute := make(chan netlink.RouteUpdate)
doneRoute := make(chan struct{})
defer close(doneRoute)
if err := netlink.RouteSubscribe(chRoute, doneRoute); err != nil {
glog.Fatal(err)
}
for {
select {
case updateLink := <-chLink:
handleLink(updateLink, netNs2Containerd)
case updateAddr := <-chAddr:
handleAddr(updateAddr, netNs2Containerd)
case updateRoute := <-chRoute:
handleRoute(updateRoute, netNs2Containerd)
}
}
}