fix(ec2-alpha): do not use string comparison in rangesOverlap (aws#…

…32269)

### Issue aws#32145

Closes aws#32145.

### Reason for this change

The rangesOverlap method was using string comparison to check if IP ranges overlapped.

### Description of changes

The rangesOverlap method was updated to compare IP ranges using the ip-num library

### Description of how you validated changes

Added two unit tests to verify correct behavior

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-ec2-alpha/lib/util.ts

@@ -260,7 +260,7 @@ export class CidrBlock {
   }
 
   /**
-   * Checks if two IP address ranges overlap.
+   * Checks if two IPv4 address ranges overlap.
    *
    * @param range1 The first IP address range represented as an array [start, end].
    * @param range2 The second IP address range represented as an array [start, end].
@@ -269,9 +269,8 @@ export class CidrBlock {
    * Note: This method assumes that the start and end addresses are valid IPv4 addresses.
    */
   public rangesOverlap(range1: [string, string], range2: [string, string]): boolean {
-    const [start1, end1] = range1;
-    const [start2, end2] = range2;
-
+    const [start1, end1] = range1.map(ip => NetworkUtils.ipToNum(ip));
+    const [start2, end2] = range2.map(ip => NetworkUtils.ipToNum(ip));
     // Check if ranges overlap
     return start1 <= end2 && start2 <= end1;
   }

packages/@aws-cdk/aws-ec2-alpha/test/integ.subnet-v2.js.snapshot/aws-cdk-vpcv2-alpha-new.template.json

@@ -3,7 +3,7 @@
   "SubnetTest3296A161": {
    "Type": "AWS::EC2::VPC",
    "Properties": {
-    "CidrBlock": "10.0.0.0/16",
+    "CidrBlock": "10.1.0.0/16",
     "EnableDnsHostnames": true,
     "EnableDnsSupport": true,
     "InstanceTenancy": "default"
@@ -26,7 +26,7 @@
    "Properties": {
     "AssignIpv6AddressOnCreation": false,
     "AvailabilityZone": "us-west-2a",
-    "CidrBlock": "10.0.0.0/24",
+    "CidrBlock": "10.1.0.0/20",
     "VpcId": {
      "Fn::GetAtt": [
       "SubnetTest3296A161",
@@ -221,7 +221,7 @@
    "Properties": {
     "AssignIpv6AddressOnCreation": false,
     "AvailabilityZone": "us-west-2a",
-    "CidrBlock": "10.0.1.0/24",
+    "CidrBlock": "10.1.128.0/20",
     "VpcId": {
      "Fn::GetAtt": [
       "SubnetTest3296A161",

packages/@aws-cdk/aws-ec2-alpha/test/integ.subnet-v2.ts

@@ -20,7 +20,7 @@ const app = new cdk.App();
 const stack = new cdk.Stack(app, 'aws-cdk-vpcv2-alpha-new');
 
 const vpc = new vpc_v2.VpcV2(stack, 'SubnetTest', {
-  primaryAddressBlock: vpc_v2.IpAddresses.ipv4('10.0.0.0/16'),
+  primaryAddressBlock: vpc_v2.IpAddresses.ipv4('10.1.0.0/16'),
   secondaryAddressBlocks: [vpc_v2.IpAddresses.amazonProvidedIpv6( {
     cidrBlockName: 'SecondaryTest',
   })],
@@ -36,7 +36,7 @@ const vpc = new vpc_v2.VpcV2(stack, 'SubnetTest', {
 new SubnetV2(stack, 'testSubnet1', {
   vpc,
   availabilityZone: 'us-west-2a',
-  ipv4CidrBlock: new IpCidr('10.0.0.0/24'),
+  ipv4CidrBlock: new IpCidr('10.1.0.0/20'),
   //defined on the basis of allocation done in IPAM console
   //ipv6CidrBlock: new Ipv6Cidr('2a05:d02c:25:4000::/60'),
   subnetType: SubnetType.PRIVATE_ISOLATED,
@@ -64,7 +64,7 @@ routeTable.addRoute('eigwRoute', '0.0.0.0/0', { gateway: igw });
 new SubnetV2(stack, 'testSubnet2', {
   vpc,
   availabilityZone: 'us-west-2a',
-  ipv4CidrBlock: new IpCidr('10.0.1.0/24'),
+  ipv4CidrBlock: new IpCidr('10.1.128.0/20'),
   routeTable: routeTable,
   subnetType: SubnetType.PUBLIC,
 });

packages/@aws-cdk/aws-ec2-alpha/test/util.test.ts

@@ -0,0 +1,38 @@
+import { CidrBlock } from '../lib/util';
+
+describe('Tests for the CidrBlock.rangesOverlap method to check if IPv4 ranges overlap', () =>{
+  test('Should return false for non-overlapping IP ranges', () => {
+    const testCidr = new CidrBlock('10.0.0.0/16');
+    const range1 = ['10.0.0.0', '10.0.15.255'] as [string, string];
+    const range2 = ['10.0.128.0', '10.0.143.255'] as [string, string];
+    expect(testCidr.rangesOverlap(range1, range2)).toBe(false);
+  });
+
+  test('Should return true for overlapping IP ranges', () => {
+    const testCidr = new CidrBlock('54.0.0.0/17');
+    const range1 = ['54.0.0.0', '54.0.127.255'] as [string, string];
+    const range2 = ['54.0.100.0', '54.0.192.255'] as [string, string];
+    expect(testCidr.rangesOverlap(range1, range2)).toBe(true);
+  });
+
+  test('Should return true for overlapping IP ranges where one range is completely inside the other', () => {
+    const testCidr = new CidrBlock('10.0.0.0/16');
+    const range1 = ['10.0.0.0', '10.0.127.255'] as [string, string];
+    const range2 = ['10.0.64.0', '10.0.65.255'] as [string, string];
+    expect(testCidr.rangesOverlap(range1, range2)).toBe(true);
+  });
+
+  test('Should return true for overlapping IP ranges where the last IP of one range is the first IP of the other', () => {
+    const testCidr = new CidrBlock('10.0.0.0/16');
+    const range1 = ['10.0.0.0', '10.0.15.255'] as [string, string];
+    const range2 = ['10.0.15.255', '10.0.255.255'] as [string, string];
+    expect(testCidr.rangesOverlap(range1, range2)).toBe(true);
+  });
+
+  test('Should return false for non-overlapping IP ranges where one range starts immediately after the other ends', () => {
+    const testCidr = new CidrBlock('10.0.0.0/16');
+    const range1 = ['10.0.0.0', '10.0.15.255'] as [string, string];
+    const range2 = ['10.0.16.0', '10.0.19.255'] as [string, string];
+    expect(testCidr.rangesOverlap(range1, range2)).toBe(false);
+  });
+});