IPv4 Subnet Calculator (C + Assembly)

A practical IPv4 subnet calculator for TCP/IP v4 addressing exercises.

This project uses a hybrid approach:

• C: parsing IPv4 / subnet masks, validation, menu UI, printing.
• x86-64 Assembly (GAS via GCC): core bitwise math for:
  • Network ID
  • Broadcast ID
  • First/Last usable host
  • Usable host count

Features (Assignment Coverage)

A) Given IP + Subnet Mask

Prints:

• Network_ID
• Broadcast_ID

B) Given Network_ID + Subnet Mask

Prints:

• IP_first (first usable)
• IP_last (last usable)
• Nr_Hostesh (usable hosts)

C) Given Network_ID + Subnet Mask + number of subnets

Generates subnets and prints for each subnet:

• Subnet_ID
• Broadcast_ID
• IP_first
• IP_last
• Nr_Hostesh

D) Extras

• IPv4 → binary conversion
• IPv4 address type (private/public/loopback/multicast/broadcast/reserved)
• Subnet membership check
• Batch processing from file
• Complete network information display

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Features Overview

✅ Core Subnet Calculations

• Network ID and Broadcast ID calculation
• First/Last usable host determination
• Usable host count
• Subnet generation

✅ Input Flexibility

• Dotted decimal notation (255.255.255.0)
• CIDR notation (/24)
• Interactive and command-line modes
• Batch processing from file

✅ Utility Features

• Binary representation of IPv4
• IP address classification
• Network membership checking
• Comprehensive network info display

✅ Quality Assurance

• Comprehensive test suite
• Assembly-optimized calculations
• Input validation
• Error handling

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Build

Linux (recommended)

make
./ipv4_calc

Requirements: gcc and standard build tools (no NASM needed).

Clean

make clean

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Usage

Interactive Mode

The program is interactive by default. You can input:

• IPv4 address: 192.168.1.10
• Subnet mask: 255.255.255.0 or CIDR: /24

./ipv4_calc

Command-Line Mode

You can also use the calculator in non-interactive mode:

# Show help
./ipv4_calc --help

# Task A: Calculate Network and Broadcast IDs
./ipv4_calc -a 192.168.1.10 /24

# Task B: Calculate host range and count
./ipv4_calc -b 192.168.1.0 255.255.255.0

# Task C: Generate subnets
./ipv4_calc -c 192.168.1.0 /24 4

# Convert IP to binary
./ipv4_calc -bin 192.168.1.1

# Show IP address type
./ipv4_calc -type 10.0.0.1

# Check if IP belongs to network
./ipv4_calc -check 192.168.1.50 192.168.1.0 /24

# Show complete network information
./ipv4_calc -info 192.168.1.0 /24

Batch Processing Mode

Process multiple commands from a file:

# Run batch commands from file
./ipv4_calc -f examples/batch_commands.txt

Example batch file format:

# Comments start with #
TYPE 10.0.0.1
BINARY 192.168.1.1
TASK_A 192.168.1.10 /24
TASK_B 192.168.1.0 /24
TASK_C 192.168.1.0 /24 4

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Testing

The project includes a comprehensive test suite:

# Run all tests
make test

# Tests cover:
# - IPv4 address parsing
# - Subnet mask validation
# - Assembly function correctness
# - Edge cases and boundary conditions

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Medium article (by Orgito)

• https://medium.com/@tech_with_orgito_/ipv4-calculator-program-written-in-c-885b363328db

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License

MIT (feel free to change).