host-local: detect missing subnet and error out

diff --git a/plugins/ipam/host-local/allocator.go b/plugins/ipam/host-local/allocator.go
index c333952..159e2cb 100644 (file)
--- a/plugins/ipam/host-local/allocator.go
+++ b/plugins/ipam/host-local/allocator.go
@@ -142,6 +142,9 @@ func (a *IPAllocator) Release(id string) error {
 }
 
 func networkRange(ipnet *net.IPNet) (net.IP, net.IP, error) {
+       if ipnet.IP == nil {
+               return nil, nil, fmt.Errorf("missing field %q in IPAM configuration", "subnet")
+       }
        ip := ipnet.IP.To4()
        if ip == nil {
                ip = ipnet.IP.To16()