SEAN

Network Device Development

PART 5 – Firewall 104: Packet Splitter

Sean

• Developer

• erinus.startup@gmail.com

• https://www.facebook.com/erinus

GitHub

https://github.com/erinus/NetworkDeviceDevelopment

Read Me

It is a series of training. If you have no experience on kernel module development, you must view

other presentations.

1. Network Device Development - Part 1: Switchhttp://www.slideshare.net/erinus/network-device-development-part-1-switch

2. Network Device Development - Part 2: Firewall 101http://www.slideshare.net/erinus/network-device-development-part-2-firewall-101

3. Network Device Development - Part 3: Firewall 102 ~ IP Filterhttp://www.slideshare.net/erinus/network-device-development-part-3-firewall-102-ip-filter

4. Network Device Development - Part 4: Firewall 103 ~ Protocol Filter & Payload Filter & Payload Modifierhttp://www.slideshare.net/erinus/network-device-development-part-4-firewall-103-protocol-filter-payload-filter-payload-modifier

First Packet Splitter

IP Fragmentation

IP Header

TCP Header

TCP Payload

IP Fragmentation

IP Header

TCP Header

TCP Payload

IP Header

TCP Header

TCP Payload

IP Header

TCP Payload

IP Fragmentation

IP Header

TCP Header

TCP Payload

IP Header

TCP Header

TCP Payload

IP Header

TCP PayloadIP_MF

IP_DF

IP Fragmentation

IP Header

TCP Header

TCP Payload

IP Header

TCP Header

TCP Payload

IP Header

TCP Payload

re-calculate checksum re-calculate checksum

Modify main.c

Modify main.c

Modify main.c

Install

$ make

$ make install

$ dmesg

Test your Firewall

Create HTTP Server on CLIENT of VMnet3

$ sudo python server.py

Test on CLIENT of VMnet2

Open Web Browser and connect:

1. http://192.168.103.128/ Success

2. http://192.168.103.128/test Success

3. http://192.168.103.128/song Success

Module Disabled

Module Disabled

Module Enabled

Module Enabled

Module Enabled

Module Enabled

Module Enabled

Next Part

Firewall 201