podman support for IPv6 networks

podman containers using IPv6 were missing the default route, breaking
deployments trying to use them.

The problem is that the default route was hardcoded to IPv4, this
takes into consideration the podman subnet IP family to generate
the corresponding default route.

Signed-off-by: Antonio Ojea <aojea@redhat.com>

4 files changed, 56 insertions, 4 deletions

diff --git a/pkg/domain/infra/abi/network.go b/pkg/domain/infra/abi/network.go
index 26383129c..fd63fc80f 100644
--- a/pkg/domain/infra/abi/network.go
+++ b/pkg/domain/infra/abi/network.go
@@ -191,7 +191,7 @@ func createBridge(r *libpod.Runtime, name string, options entities.NetworkCreate
 	var plugins []network.CNIPlugins
 	var routes []network.IPAMRoute
 
-	defaultRoute, err := network.NewIPAMDefaultRoute()
+	defaultRoute, err := network.NewIPAMDefaultRoute(network.IsIPv6(subnet.IP))
 	if err != nil {
 		return "", err
 	}
diff --git a/pkg/network/ip.go b/pkg/network/ip.go
index 1798cd939..ba93a0d05 100644
--- a/pkg/network/ip.go
+++ b/pkg/network/ip.go
@@ -12,3 +12,8 @@ func CalcGatewayIP(ipn *net.IPNet) net.IP {
 	nid := ipn.IP.Mask(ipn.Mask)
 	return ip.NextIP(nid)
 }
+
+// IsIPv6 returns if netIP is IPv6.
+func IsIPv6(netIP net.IP) bool {
+	return netIP != nil && netIP.To4() == nil
+}
diff --git a/pkg/network/netconflist.go b/pkg/network/netconflist.go
index 4271d3f54..8187fdb39 100644
--- a/pkg/network/netconflist.go
+++ b/pkg/network/netconflist.go
@@ -6,6 +6,11 @@ import (
 	"path/filepath"
 )
 
+const (
+	defaultIPv4Route = "0.0.0.0/0"
+	defaultIPv6Route = "::/0"
+)
+
 // NcList describes a generic map
 type NcList map[string]interface{}
 
@@ -86,9 +91,13 @@ func NewIPAMRoute(r *net.IPNet) IPAMRoute { //nolint:interfacer
 }
 
 // NewIPAMDefaultRoute creates a new IPAMDefault route of
-// 0.0.0.0/0
-func NewIPAMDefaultRoute() (IPAMRoute, error) {
-	_, n, err := net.ParseCIDR("0.0.0.0/0")
+// 0.0.0.0/0 for IPv4 or ::/0 for IPv6
+func NewIPAMDefaultRoute(isIPv6 bool) (IPAMRoute, error) {
+	route := defaultIPv4Route
+	if isIPv6 {
+		route = defaultIPv6Route
+	}
+	_, n, err := net.ParseCIDR(route)
 	if err != nil {
 		return IPAMRoute{}, err
 	}
diff --git a/pkg/network/netconflist_test.go b/pkg/network/netconflist_test.go
new file mode 100644
index 000000000..a82a0140a
--- /dev/null
+++ b/pkg/network/netconflist_test.go
@@ -0,0 +1,38 @@
+package network
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestNewIPAMDefaultRoute(t *testing.T) {
+
+	tests := []struct {
+		name   string
+		isIPv6 bool
+		want   IPAMRoute
+	}{
+		{
+			name:   "IPv4 default route",
+			isIPv6: false,
+			want:   IPAMRoute{defaultIPv4Route},
+		},
+		{
+			name:   "IPv6 default route",
+			isIPv6: true,
+			want:   IPAMRoute{defaultIPv6Route},
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := NewIPAMDefaultRoute(tt.isIPv6)
+			if err != nil {
+				t.Errorf("no errorr expected: %v", err)
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("NewIPAMDefaultRoute() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}