Project 3: chirouter

In this project you will be implementing a simple IP router capable of routing IPv4 datagrams between multiple networks. This router will have a static routing table, so you will not have to deal with implementing a routing protocol like RIP or OSPF; instead, the project will focus on the routing of IP datagrams. While, at a high level, this just involves receiving IP datagrams and figuring out what interface they should be sent on, this requires building additional functionality before you can actually start routing IP datagrams.

Please refer to the following documents to complete this project:

• chirouter specification

• Project 3 rubric

• Project 3 tips

Take into account that this project requires using a network simulator that needs to be run with root privileges on a Linux machine. For students using Windows or Mac, we provide a Docker container that you can use to run the network simulator on your computer.

Submission Timeline

This project has one required submission, and an optional resubmission:

Submission	Requirements	Due Date
Project 3	chirouter (entire project)	Thursday, December 5th, 8pm
Resubmission (Optional)	You may submit a revised version to improve your Completeness score only	Friday, December 13th, 8pm

Please see Project 3 rubric for more details on how your submission will be graded.

Initializing your Project 3 Repository

Make sure that you have read the Getting Started page before following the instructions below.

One-time setup instructions

Only one team member needs to run these commands. Create an empty directory and, inside that directory run the following commands. In the commands below, $REPO_URL refers to the SSH URL of your repository. To get this URL, log into GitHub and navigate to your project repository. Then, under “Quick setup — if you’ve done this kind of thing before”, make sure the “SSH” button is selected, and copy the URL that appears next to it. It should look something like this: git@github.com:uchicago-cmsc23320-aut-24/chirc-p1-jdoe-jrandom.git

git init
git remote add origin $REPO_URL
git remote add upstream https://github.com/uchicago-cs/chirouter.git
git pull upstream main
git push -u origin main

Cloning instructions

Once the repository has been set up, you can clone the repository in other locations as follows:

git clone $REPO_URL
git remote add upstream https://github.com/uchicago-cs/chirouter.git

Submission

Before submitting, make sure you’ve added, committed, and pushed all your code to GitHub. You will submit your code through Gradescope, which you can access through our Canvas site.

When submitting through Gradescope, you will be asked to select a repository to submit. Make sure that you select the correct repository and branch. Please note that you can submit as many times as you want before the deadline.

Please note that you must make a single submission per pair of students (do not make two submissions, one per student). When making your submission, you will be allowed to add “team members” to your submission. Make sure you add your project partner in your submission.

In this project, Gradescope will only fetch the following files from your repository:

• src/c/router.c

• src/c/arp.c

• src/c/utils.c

• src/c/utils.h

• The DOCUMENTATION.md file in the root of your repository

Once you submit your files, an “autograder” will run. Unlike Projects 1 and 2, the autograder will not run any automated tests, because the chirouter tests require running a Docker container with elevated privileges, which is not possible on Gradescope’s autograding infrastructure. Instead, the tests will be run manually by the graders (the autograder will just build your code to ensure it builds).