Subnet Analyzer

This Rust application calculates various subnet-related information, similar to the functionality provided by ipcalc. It can aggregate a list of subnets into a common network address and prefix length, determine subnet information (e.g., broadcast address, wildcard mask), and calculate a new subnet mask based on the required number of subnets and hosts.

Usage

Running the Application

To aggregate IPs, use the following command:

cargo run --release aggregate "192.168.100.0/27" "192.168.100.32/27" "192.168.100.64/26"

To check subnet information, such as broadcast and wildcard addresses, use:

cargo run --release info "192.168.100.0/27"

To determine a new subnet mask based on NetID and the required number of subnets and hosts:

cargo run --release mask "198.31.0.0" "90" "350"

Notes:

• If a prefix is not provided, the default based on the IP class will be applied.
• Quotation marks are unnecessary.

Tests

The application includes unit tests to verify the functionality of subnet parsing, aggregation, and utility functions. To run the tests, use the following command:

cargo test

Subnet Aggregation Algorithm

The subnet aggregation algorithm combines multiple subnets into a single, larger subnet by determining the common bits shared among them. This can help optimize routing and reduce the size of routing tables.

Steps of the Algorithm

1. Bitwise AND Operation:

   • Perform a bitwise AND operation on all subnet IP addresses, masked by their respective subnet masks. This step identifies the common bits shared by all subnets.

2. Counting Common Bits:

   • Count the number of common prefix bits across all subnets. Iterate over each bit position from the most significant to the least significant, checking if all subnets share the same bit value at that position.

3. Constructing the Aggregated Network Address:

   • Once the common prefix length is determined, construct the aggregated network address by performing a bitwise AND operation between the common prefix and a mask that zeroes out the bits beyond the common prefix length.

Example

Given the following subnets:

• 192.168.100.0/27
• 192.168.100.32/27
• 192.168.100.64/26

Step 1: Perform Bitwise AND on All Subnets

11000000.10101000.01100100.00000000 (192.168.100.0/27)
11000000.10101000.01100100.00100000 (192.168.100.32/27)
11000000.10101000.01100100.01000000 (192.168.100.64/26)
-----------------------------------
11000000.10101000.01100100.00000000 (Result of AND operation)

Step 2: Count the Common Bits

11000000.10101000.01100100.00000000
11000000.10101000.01100100.00100000
11000000.10101000.01100100.01000000
---------------------------- (Common bits = 25)

Step 3: Obtain New Mask by Zeroing Out Uncommon Bits

let new_mask = !0 << (32 - common_bits);
// New mask: 11111111.11111111.11111111.10000000 (255.255.255.128)

Step 4: Construct the Aggregated Network Address

• The aggregated network address is 192.168.100.0/25.