aws_ec2_transit_gateway_route: cidr match is unreliable

aws/ec2_transit_gateway.go

@@ -109,8 +109,9 @@ func ec2DescribeTransitGatewayRoute(conn *ec2.EC2, transitGatewayRouteTableID, d
 		if route == nil {
 			continue
 		}
-
-		if aws.StringValue(route.DestinationCidrBlock) == destination {
+		if cidrBlocksEqual(aws.StringValue(route.DestinationCidrBlock), destination) {
+			cidrString := canonicalCidrBlock(aws.StringValue(route.DestinationCidrBlock))
+			route.DestinationCidrBlock = &cidrString
 			return route, nil
 		}
 	}

aws/resource_aws_ec2_transit_gateway_route.go

@@ -24,9 +24,11 @@ func resourceAwsEc2TransitGatewayRoute() *schema.Resource {
 
 		Schema: map[string]*schema.Schema{
 			"destination_cidr_block": {
-				Type:     schema.TypeString,
-				Required: true,
-				ForceNew: true,
+				Type:             schema.TypeString,
+				Required:         true,
+				ForceNew:         true,
+				ValidateFunc:     validateCIDRNetworkAddress,
+				DiffSuppressFunc: suppressEqualCIDRBlockDiffs,
 			},
 			"blackhole": {
 				Type:     schema.TypeBool,

aws/resource_aws_ec2_transit_gateway_route_test.go

@@ -39,6 +39,36 @@ func TestAccAWSEc2TransitGatewayRoute_basic(t *testing.T) {
 	})
 }
 
+func TestAccAWSEc2TransitGatewayRoute_basic_ipv6(t *testing.T) {
+	var transitGatewayRoute1 ec2.TransitGatewayRoute
+	resourceName := "aws_ec2_transit_gateway_route.test_ipv6"
+	transitGatewayResourceName := "aws_ec2_transit_gateway.test"
+	transitGatewayVpcAttachmentResourceName := "aws_ec2_transit_gateway_vpc_attachment.test"
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t); testAccPreCheckAWSEc2TransitGateway(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSEc2TransitGatewayRouteDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAWSEc2TransitGatewayRouteConfigDestinationCidrBlock(),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSEc2TransitGatewayRouteExists(resourceName, &transitGatewayRoute1),
+					resource.TestCheckResourceAttr(resourceName, "destination_cidr_block", "2001:db8::/56"),
+					resource.TestCheckResourceAttr(resourceName, "blackhole", "false"),
+					resource.TestCheckResourceAttrPair(resourceName, "transit_gateway_attachment_id", transitGatewayVpcAttachmentResourceName, "id"),
+					resource.TestCheckResourceAttrPair(resourceName, "transit_gateway_route_table_id", transitGatewayResourceName, "association_default_route_table_id"),
+				),
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
 func TestAccAWSEc2TransitGatewayRoute_blackhole(t *testing.T) {
 	var transitGatewayRoute1 ec2.TransitGatewayRoute
 	resourceName := "aws_ec2_transit_gateway_route.test_blackhole"
@@ -248,6 +278,12 @@ resource "aws_ec2_transit_gateway_route" "test" {
   transit_gateway_route_table_id = aws_ec2_transit_gateway.test.association_default_route_table_id
 }
 
+resource "aws_ec2_transit_gateway_route" "test_ipv6" {
+  destination_cidr_block         = "2001:db8::/56"
+  transit_gateway_attachment_id  = aws_ec2_transit_gateway_vpc_attachment.test.id
+  transit_gateway_route_table_id = aws_ec2_transit_gateway.test.association_default_route_table_id
+}
+
 resource "aws_ec2_transit_gateway_route" "test_blackhole" {
   destination_cidr_block         = "10.1.0.0/16"
   blackhole                      = true

aws/validators.go

@@ -833,6 +833,17 @@ func cidrBlocksEqual(cidr1, cidr2 string) bool {
 	return ip2.String() == ip1.String() && ipnet2.String() == ipnet1.String()
 }
 
+// canonicalCidrBlock returns the canonical representation of a CIDR block.
+// This function is especially useful for hash functions for sets which include IPv6 CIDR blocks.
+func canonicalCidrBlock(cidr string) string {
+	_, ipnet, err := net.ParseCIDR(cidr)
+	if err != nil {
+		return cidr
+	}
+
+	return ipnet.String()
+}
+
 func validateHTTPMethod() schema.SchemaValidateFunc {
 	return validation.StringInSlice([]string{
 		"ANY",

aws/validators_test.go

@@ -544,6 +544,22 @@ func Test_cidrBlocksEqual(t *testing.T) {
 		}
 	}
 }
+func Test_canonicalCidrBlock(t *testing.T) {
+	for _, ts := range []struct {
+		cidr     string
+		expected string
+	}{
+		{"10.2.2.0/24", "10.2.2.0/24"},
+		{"::/0", "::/0"},
+		{"::0/0", "::/0"},
+		{"", ""},
+	} {
+		got := canonicalCidrBlock(ts.cidr)
+		if ts.expected != got {
+			t.Fatalf("canonicalCidrBlock(%q) should be: %q, got: %q", ts.cidr, ts.expected, got)
+		}
+	}
+}
 
 func TestValidateLogMetricFilterName(t *testing.T) {
 	validNames := []string{

website/docs/r/ec2_transit_gateway_route.html.markdown

@@ -36,7 +36,7 @@ resource "aws_ec2_transit_gateway_route" "example" {
 
 The following arguments are supported:
 
-* `destination_cidr_block` - (Required) IPv4 CIDR range used for destination matches. Routing decisions are based on the most specific match.
+* `destination_cidr_block` - (Required) IPv4 or IPv6 RFC1924 CIDR used for destination matches. Routing decisions are based on the most specific match.
 * `transit_gateway_attachment_id` - (Optional) Identifier of EC2 Transit Gateway Attachment (required if `blackhole` is set to false).
 * `blackhole` - (Optional) Indicates whether to drop traffic that matches this route (default to `false`).
 * `transit_gateway_route_table_id` - (Required) Identifier of EC2 Transit Gateway Route Table.