From 08ff3b641341a1124db8ebb123f61b420fcb3328 Mon Sep 17 00:00:00 2001
From: Tomofumi Hayashi <tohayash@redhat.com>
Date: Wed, 16 Sep 2020 15:09:00 +0900
Subject: [PATCH] ipvlan: make master config as optional

This change makes ipvlan master parameter optional.
Default to default route interface as macvlan does.

Signed-off-by: Tomofumi Hayashi <tohayash@redhat.com>
---
 plugins/main/ipvlan/README.md      |  2 +-
 plugins/main/ipvlan/ipvlan.go      | 35 ++++++++++++++++++----
 plugins/main/ipvlan/ipvlan_test.go | 48 +++++++++++++++++++++++++++++-
 3 files changed, 78 insertions(+), 7 deletions(-)

diff --git a/plugins/main/ipvlan/README.md b/plugins/main/ipvlan/README.md
index 0df1d5ca..aa87469a 100644
--- a/plugins/main/ipvlan/README.md
+++ b/plugins/main/ipvlan/README.md
@@ -27,7 +27,7 @@ Because all ipvlan interfaces share the MAC address with the host interface, DHC
 
 * `name` (string, required): the name of the network.
 * `type` (string, required): "ipvlan".
-* `master` (string, required unless chained): name of the host interface to enslave.
+* `master` (string, optional): name of the host interface to enslave. Defaults to default route interface.
 * `mode` (string, optional): one of "l2", "l3", "l3s". Defaults to "l2".
 * `mtu` (integer, optional): explicitly set MTU to the specified value. Defaults to the value chosen by the kernel.
 * `ipam` (dictionary, required unless chained): IPAM configuration to be used for this network.
diff --git a/plugins/main/ipvlan/ipvlan.go b/plugins/main/ipvlan/ipvlan.go
index ba24b54e..19a69903 100644
--- a/plugins/main/ipvlan/ipvlan.go
+++ b/plugins/main/ipvlan/ipvlan.go
@@ -72,12 +72,18 @@ func loadConf(bytes []byte, cmdCheck bool) (*NetConf, string, error) {
 	}
 	if n.Master == "" {
 		if result == nil {
-			return nil, "", fmt.Errorf(`"master" field is required. It specifies the host interface name to virtualize`)
-		}
-		if len(result.Interfaces) == 1 && result.Interfaces[0].Name != "" {
-			n.Master = result.Interfaces[0].Name
+			defaultRouteInterface, err := getDefaultRouteInterfaceName()
+
+			if err != nil {
+				return nil, "", err
+			}
+			n.Master = defaultRouteInterface
 		} else {
-			return nil, "", fmt.Errorf("chained master failure. PrevResult lacks a single named interface")
+			if len(result.Interfaces) == 1 && result.Interfaces[0].Name != "" {
+				n.Master = result.Interfaces[0].Name
+			} else {
+				return nil, "", fmt.Errorf("chained master failure. PrevResult lacks a single named interface")
+			}
 		}
 	}
 	return n, n.CNIVersion, nil
@@ -167,6 +173,25 @@ func createIpvlan(conf *NetConf, ifName string, netns ns.NetNS) (*current.Interf
 	return ipvlan, nil
 }
 
+func getDefaultRouteInterfaceName() (string, error) {
+	routeToDstIP, err := netlink.RouteList(nil, netlink.FAMILY_ALL)
+	if err != nil {
+		return "", err
+	}
+
+	for _, v := range routeToDstIP {
+		if v.Dst == nil {
+			l, err := netlink.LinkByIndex(v.LinkIndex)
+			if err != nil {
+				return "", err
+			}
+			return l.Attrs().Name, nil
+		}
+	}
+
+	return "", fmt.Errorf("no default route interface found")
+}
+
 func cmdAdd(args *skel.CmdArgs) error {
 	n, cniVersion, err := loadConf(args.StdinData, false)
 	if err != nil {
diff --git a/plugins/main/ipvlan/ipvlan_test.go b/plugins/main/ipvlan/ipvlan_test.go
index 2da00659..114dab42 100644
--- a/plugins/main/ipvlan/ipvlan_test.go
+++ b/plugins/main/ipvlan/ipvlan_test.go
@@ -234,7 +234,7 @@ func ipvlanAddCheckDelTest(conf string, netName string, IFNAME string, originalN
 
 	args.StdinData = confString
 
-	// CNI Check on macvlan in the target namespace
+	// CNI Check on ipvlan in the target namespace
 	err = originalNS.Do(func(ns.NetNS) error {
 		defer GinkgoRecover()
 
@@ -465,4 +465,50 @@ var _ = Describe("ipvlan Operations", func() {
 
 		ipvlanAddCheckDelTest(conf, "ipvlanTest2", IFNAME, originalNS)
 	})
+
+	It("configures and deconfigures a ipvlan link with ADD/DEL, without master config", func() {
+		const IFNAME = "ipvl0"
+		conf := `{
+    "cniVersion": "0.3.1",
+    "name": "mynet",
+    "type": "ipvlan",
+    "ipam": {
+        "type": "host-local",
+        "subnet": "10.1.2.0/24"
+    }
+}`
+
+		targetNs, err := testutils.NewNS()
+		Expect(err).NotTo(HaveOccurred())
+		defer targetNs.Close()
+
+		// Make MASTER_NAME as default route interface
+		err = originalNS.Do(func(ns.NetNS) error {
+			defer GinkgoRecover()
+
+			link, err := netlink.LinkByName(MASTER_NAME)
+			Expect(err).NotTo(HaveOccurred())
+			err = netlink.LinkSetUp(link)
+			Expect(err).NotTo(HaveOccurred())
+
+			var address = &net.IPNet{IP: net.IPv4(192, 0, 0, 1), Mask: net.CIDRMask(24, 32)}
+			var addr = &netlink.Addr{IPNet: address}
+			err = netlink.AddrAdd(link, addr)
+			Expect(err).NotTo(HaveOccurred())
+
+			// add default gateway into MASTER
+			dst := &net.IPNet{
+				IP:   net.IPv4(0, 0, 0, 0),
+				Mask: net.CIDRMask(0, 0),
+			}
+			ip := net.IPv4(192, 0, 0, 254)
+			route := netlink.Route{LinkIndex: link.Attrs().Index, Dst: dst, Gw: ip}
+			err = netlink.RouteAdd(&route)
+			Expect(err).NotTo(HaveOccurred())
+			return nil
+		})
+		Expect(err).NotTo(HaveOccurred())
+
+		ipvlanAddDelTest(conf, IFNAME, originalNS)
+	})
 })