func electBridgeIPv4(config *NetworkConfiguration) (*net.IPNet, error) {
// Use the requested IPv4 CIDR when available.
if config.AddressIPv4 != nil {
return config.AddressIPv4, nil
}
// We don't check for an error here, because we don't really care if we
// can't read /etc/resolv.conf. So instead we skip the append if resolvConf
// is nil. It either doesn't exist, or we can't read it for some reason.
nameservers := []string{}
if resolvConf, _ := readResolvConf(); resolvConf != nil {
nameservers = append(nameservers, getNameserversAsCIDR(resolvConf)...)
}
// Try to automatically elect appropriate bridge IPv4 settings.
for _, n := range bridgeNetworks {
if err := netutils.CheckNameserverOverlaps(nameservers, n); err == nil {
if err := netutils.CheckRouteOverlaps(n); err == nil {
return n, nil
}
}
}
return nil, IPv4AddrRangeError(config.BridgeName)
}
// FindAvailableNetwork returns a network from the passed list which does not
// overlap with existing interfaces in the system
func FindAvailableNetwork(list []*net.IPNet) (*net.IPNet, error) {
// We don't check for an error here, because we don't really care if we
// can't read /etc/resolv.conf. So instead we skip the append if resolvConf
// is nil. It either doesn't exist, or we can't read it for some reason.
var nameservers []string
if rc, err := resolvconf.Get(); err == nil {
nameservers = resolvconf.GetNameserversAsCIDR(rc.Content)
}
for _, nw := range list {
if err := netutils.CheckNameserverOverlaps(nameservers, nw); err == nil {
if err := netutils.CheckRouteOverlaps(nw); err == nil {
return nw, nil
}
}
}
return nil, fmt.Errorf("no available network")
}
func isOverlap(nw *net.IPNet) bool {
var nameservers []string
if rc, err := resolvconf.Get(); err == nil {
nameservers = resolvconf.GetNameserversAsCIDR(rc.Content)
}
if err := netutils.CheckNameserverOverlaps(nameservers, nw); err != nil {
return true
}
if err := netutils.CheckRouteOverlaps(nw); err != nil {
return true
}
return false
}
func checkOverlap(nw *net.IPNet) error {
var nameservers []string
if rc, err := resolvconf.Get(); err == nil {
nameservers = resolvconf.GetNameserversAsCIDR(rc.Content)
}
if err := netutils.CheckNameserverOverlaps(nameservers, nw); err != nil {
return fmt.Errorf("overlay subnet %s failed check with nameserver: %v: %v", nw.String(), nameservers, err)
}
if err := netutils.CheckRouteOverlaps(nw); err != nil {
return fmt.Errorf("overlay subnet %s failed check with host route table: %v", nw.String(), err)
}
return nil
}