IPv6 Subnet Calculator Development Notes in HarmonyOS

About HarmonyOS 5

HarmonyOS 5 (also known as HarmonyOS Next) represents a revolutionary step in the evolution of Huawei's distributed operating system. As someone who has been following its development closely, I can attest to the remarkable improvements in this version. The system's microkernel architecture not only enhances security but also provides unprecedented flexibility in cross-device collaboration. What excites me most about HarmonyOS 5 is its focus on developer experience - the new ArkTS language, enhanced UI components, and improved debugging tools have made development much more efficient. The distributed capabilities allow us to create truly seamless experiences across different devices, from smartphones to tablets, smart TVs, and IoT devices.

About the Author

I am a dedicated HarmonyOS developer based in China, with over three years of experience in the ecosystem. My journey with HarmonyOS began with its early versions, and I've witnessed its remarkable evolution. As a developer who has contributed to several open-source HarmonyOS projects, I've gained valuable insights into its architecture and best practices. I'm particularly passionate about network tools and subnet management, which led me to develop this comprehensive IPv6 subnet calculator module. Through my blog and GitHub repositories, I've been sharing my experiences and helping other developers navigate the exciting world of HarmonyOS development.

Basic Knowledge

Let's first understand IPv6 addresses and subnets:

What is an IPv6 Address
- 128-bit address format
- Written in hexadecimal
- 8 groups of 16 bits
- Groups separated by colons
- Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
IPv6 Address Types
- Global Unicast: 2000::/3
- Unique Local: fc00::/7
- Link Local: fe80::/10
- Multicast: ff00::/8
- Loopback: ::1/128
IPv6 Subnetting
- Uses prefix length notation
- Example: /64 means first 64 bits are network
- Common prefix lengths: /48, /56, /64
- Each subnet typically /64
Address Compression
- Leading zeros in groups can be omitted
- One or more groups of zeros can be replaced with ::
- Example: 2001:db8::1
Address Validation
- Must be valid hexadecimal
- Must have correct number of groups
- Must follow compression rules
- Must be within valid ranges

Preface

Recently, while developing the HarmonyOS Developer Toolbox, we wanted to add an IPv6 subnet calculator feature. This feature is mainly used to calculate subnet information for IPv6 addresses, such as network address, broadcast address, and available host count. Initially, we thought it would be similar to IPv4, but we found that IPv6 has its own unique characteristics and challenges.

I. Feature Description

1.1 Main Features

Calculate network address
Calculate broadcast address
Calculate available hosts
Calculate subnet mask
Support various IPv6 formats
Display address type
Support prefix length

1.2 Interface Features

IPv6 address input field
One-click copy results
Display detailed calculations
Favorites support
Usage instructions

II. Implementation Process

2.1 Calculation Principle

IPv6 subnet calculation involves bitwise operations on 128-bit addresses:

Network Address Calculation
- AND operation between IP and subnet mask
- Example: 2001:db8::1/64
- Network address is 2001:db8::
Broadcast Address Calculation
- Set all host bits to 1
- Example: 2001:db8::/64
- Broadcast address is 2001:db8::ffff:ffff:ffff:ffff
Available Host Count Calculation
- 2^(128-prefix length)
- Example: /64 is 2^64 hosts
Subnet Mask Calculation
- Generated based on prefix length
- Example: /64 is ffff:ffff:ffff:ffff:0000:0000:0000:0000
Address Type Determination
- Check first bits of address
- Determine if global, local, or special

2.2 Code Implementation

@Entry
@Component
struct Ipv6subnetcalculator {
  @State ipAddress: string = '';           // IP to calculate
  @State networkMask: string = '';         // Network mask
  @State networkAddress: string = '';      // Network address
  @State subnetMask: string = '';          // Subnet mask
  @State subnetMaskBinary: string = '';    // Subnet mask binary
  @State subnetMaskCIDR: string = '';      // Subnet mask CIDR
  @State totalHosts: string = '';          // Available hosts
  @State firstHost: string = '';           // First address
  @State lastHost: string = '';            // Last address
  @State broadcastAddress: string = '';    // Broadcast address
  @State addressType: string = '';         // Address type

  // Calculate subnet information
  private calculateSubnet() {
    try {
      // Preprocess input
      const processedInput = this.preprocessIPv6Address(this.ipAddress);

      // Parse input
      let ip = processedInput;
      let cidr = '64'; // Default subnet mask
      if (processedInput.includes('/')) {
        const parts = processedInput.split('/');
        ip = parts[0];
        cidr = parts[1];
      }

      // Validate IPv6 address format
      if (!this.isValidIPv6Address(ip)) {
        throw new Error('Invalid IPv6 address format');
      }

      const prefix = parseInt(cidr);
      if (isNaN(prefix) || prefix < 0 || prefix > 128) {
        throw new Error('Invalid CIDR prefix (0-128)');
      }

      // Calculate subnet mask
      const subnetMaskParts = this.calculateSubnetMask(prefix);
      this.subnetMask = this.formatIPv6(subnetMaskParts);
      this.subnetMaskBinary = this.formatBinary(subnetMaskParts);
      this.subnetMaskCIDR = '/' + prefix;

      // Calculate network address
      const ipParts = this.parseIPv6(ip);
      const networkParts = this.calculateNetworkAddress(ipParts, subnetMaskParts);
      this.networkAddress = this.formatIPv6(networkParts);
      this.networkMask = this.networkAddress + this.subnetMaskCIDR;

      // Calculate broadcast address
      const broadcastParts = this.calculateBroadcastAddress(networkParts, prefix);
      this.broadcastAddress = this.formatIPv6(broadcastParts);

      // Calculate available host range
      const firstHostParts = [...networkParts];
      firstHostParts[7] += 1;
      this.firstHost = this.formatIPv6(firstHostParts);

      const lastHostParts = [...broadcastParts];
      lastHostParts[7] -= 1;
      this.lastHost = this.formatIPv6(lastHostParts);

      // Calculate available host count
      this.totalHosts = this.calculateHostCount(prefix);

      // Determine address type
      this.addressType = this.determineAddressType(ipParts);

    } catch (err) {
      console.error('Calculation failed:', err);
      throw err;
    }
  }

  // Helper methods
  private preprocessIPv6Address(address: string): string {
    // Implementation details...
  }

  private isValidIPv6Address(address: string): boolean {
    // Implementation details...
  }

  private calculateSubnetMask(prefix: number): number[] {
    // Implementation details...
  }

  private formatIPv6(parts: number[]): string {
    // Implementation details...
  }

  private parseIPv6(address: string): number[] {
    // Implementation details...
  }

  private calculateNetworkAddress(ip: number[], mask: number[]): number[] {
    // Implementation details...
  }

  private calculateBroadcastAddress(network: number[], prefix: number): number[] {
    // Implementation details...
  }

  private calculateHostCount(prefix: number): string {
    // Implementation details...
  }

  private determineAddressType(parts: number[]): string {
    // Implementation details...
  }
}

III. Development Experience

3.1 Problems Encountered

IPv6 Format Validation
- Problem: Complex address format
- Solution: Implemented comprehensive validation
Edge Cases
- Problem: Special IPv6 addresses
- Solution: Added multiple checks
Performance Issues
- Problem: Large number calculations
- Solution: Optimized algorithms
Display Issues
- Problem: Long addresses
- Solution: Implemented compression

3.2 Optimization Suggestions

Feature Optimization
- Support more formats
- Add calculation history
- Support batch calculations
Performance Optimization
- Optimize calculation speed
- Reduce memory usage
- Release resources promptly
User Experience
- Add calculation history
- Support result sharing
- Optimize animations
Security
- Validate input format
- Limit calculation frequency
- Protect user privacy

IV. Summary

This IPv6 subnet calculator has all the basic features and can:

Calculate subnet information
Plan network addresses
Troubleshoot network issues
Learn about IPv6 networking

V. Reference Resources

HarmonyOS Application Development Guide

Welcome to Experience

This IPv6 subnet calculator has been integrated into the HarmonyOS Developer Toolbox. Welcome to download and experience it!

HarmonyOS Developer Toolbox

Author: In the World of Development
Email: 1743914721@qq.com
Copyright Notice: This article is an original work by the blogger, please include the original source link and this statement when reprinting.