Set the bip network value as the subnet

Dont assign the --bip value directly to the subnet
for the default bridge. Instead use the network value
from the ParseCIDR output

Addresses: https://github.com/moby/moby/issues/40392

Signed-off-by: Arko Dasgupta <arko.dasgupta@docker.com>

daemon/daemon_unix.go

@@ -1008,11 +1008,11 @@ func initBridgeDriver(controller libnetwork.NetworkController, config *config.Co
 	}
 
 	if config.BridgeConfig.IP != "" {
-		ipamV4Conf.PreferredPool = config.BridgeConfig.IP
-		ip, _, err := net.ParseCIDR(config.BridgeConfig.IP)
+		ip, ipNet, err := net.ParseCIDR(config.BridgeConfig.IP)
 		if err != nil {
 			return err
 		}
+		ipamV4Conf.PreferredPool = ipNet.String()
 		ipamV4Conf.Gateway = ip.String()
 	} else if bridgeName == bridge.DefaultBridgeName && ipamV4Conf.PreferredPool != "" {
 		logrus.Infof("Default bridge (%s) is assigned with an IP address %s. Daemon option --bip can be used to set a preferred IP address", bridgeName, ipamV4Conf.PreferredPool)

integration/network/service_test.go

@@ -193,7 +193,7 @@ func TestDaemonWithBipAndDefaultNetworkPool(t *testing.T) {
 	out, err := c.NetworkInspect(context.Background(), "bridge", types.NetworkInspectOptions{})
 	assert.NilError(t, err)
 	// Make sure BIP IP doesn't get override with new default address pool .
-	assert.Equal(t, out.IPAM.Config[0].Subnet, "172.60.0.1/16")
+	assert.Equal(t, out.IPAM.Config[0].Subnet, "172.60.0.0/16")
 	delInterface(t, defaultNetworkBridge)
 }