CIDRizer

Currently live at cidrizer.com

Motivation:

"Our VPC was define as 10.82.208.0/20, and so far subnets of 10.82.217.128/27 and 10.82.219.0/24, but what IP and ranges do we have left?!..."

It's hard to manage CIDR space in a big team.

Here's a web-app to help organize.

Commands

Developed with:

• npmv6.13
• nodev13.7

npm test

• (see file test/test_theProcedure.js which has good test coverage of what the calculations actually do)

npm start

• please note that the above invokes index.js
• if deployed via serverless.yml, there exists a nearly equivelant serverless_for_lambda.js which instead exports via the serverless-http module

Test scenarios

Valid test

(first line of input is always the umbrealla VPC/Account, and subsequent lines are inferred as fitting within line 1's space)

10.10.10.0/24   # Client 3
10.10.10.32/29  # bastion(s)
10.10.10.128/29 # content srvs

yields

CIDR,2^(32-n),Avail.,First,Last
10.10.10.0/27,32,30,10.10.10.0,10.10.10.31,
10.10.10.32/29,8,6,10.10.10.32,10.10.10.39,
10.10.10.40/29,8,6,10.10.10.40,10.10.10.47,
10.10.10.48/28,16,14,10.10.10.48,10.10.10.63,
10.10.10.64/26,64,62,10.10.10.64,10.10.10.127,
10.10.10.128/29,8,6,10.10.10.128,10.10.10.135,
10.10.10.136/29,8,6,10.10.10.136,10.10.10.143,
10.10.10.144/28,16,14,10.10.10.144,10.10.10.159,
10.10.10.160/27,32,30,10.10.10.160,10.10.10.191,
10.10.10.192/26,64,62,10.10.10.192,10.10.10.255,

Thorough and Valid Test

10.82.208.0/20

10.82.218.128/27
10.82.217.0/24
10.82.222.0/29
10.82.221.0/29

yeilds ... a lot. You'll just have to try it out.

Negative Test

Lots of overlapping and range violations...

10.82.208.0/20

10.82.217.128/27
10.82.217.0/24
10.1.244.0/29
10.253.244.0/29

yields

10.1.244.0/29 (first ip 10.1.244.0) precedes the account space 10.82.208.0/20 (first ip 10.82.208.0)

10.253.244.0/29 (last ip 10.253.244.7) exceeds the account space 10.82.208.0/20 (last ip 10.82.223.255)

10.82.217.128/27 (first 10.82.217.128) overlaps with 10.82.217.0/24 (last 10.82.217.255)

Invoke with a Curl

curl -XPOST -H "Content-type: application/json" -d '{ "userInput": "10.0.0.0/18 \n 10.0.0.0/22" }' 'http://localhost:80/do_cidr/'