Description

1. You are given the virtual network in Fig. 1. This network has two subnets, and one node common to both these subnets. Your first exercise is to write a simple packet sniffer at node

Figure 1: A network with 2 subnets.
r1. This packet sniffer should print the MAC addresses (source and destination), IP addresses (source and destination) of all IP packets sent and received by r1. Refer https://www. binarytides.com/raw-sockets-c-code-linux/ and http://squidarth.com/networking/
2. Modify the packet sniffer in the previous exercise to print the MAC addresses (source and destination), IP addresses (source and destination) of only those IP packets that are received [50]
by r1 on interface eth1.
3. Enhance the program created in the previous exercise so that you transfer IP packets across the subnets in Fig. 1. Infact, you will essentially be building a rudimentary router. Some hints [20]
can be found at https://opensourceforu.com/2015/03/a-guide-to-using-raw-sockets/
[30]
End of paper