Kernel_UDP

 

A kernel module that implements client - server communication in UDP.

Two kernel modules that implement UDP client - server communication.
Tested using Ubuntu 17.4 kernel version 4.10.0-26-generic.

Once running, the client send HELLO to server, that answers OK.

Files

kern_udp/udp_client.c: kernel module for client
kern_udp/udp_server.c: kernel module for server

Each module has the equivalent in user space under the folder used_udp. They also have the same parameters and perform the same operations

Usage

1. Compile ( make in this folder)
2. Load server with sudo insmod udp_server.ko (see Parameters for optional parameters)
3. Load client with sudo insmod udp_client.ko (see Parameters for optional parameters)
4. Observe in /var/log/kern.log the message passing:
   Load server

[  +4.514179] k_server: opt: p
[  +0.000006] Socket created
[  +0.000008] Socket is bind to 127.0.0.1:4000
[  +0.000057] k_server: Thread running
[  +0.000031] k_server: Performing a simple test: this module will wait to receive HELLO from client, replying with OK

Load client

[ +11.079634] k_client: Destination is 127.0.0.1:4000
[  +0.000003] k_client: opt: p, ns: 1, tsec: -1, ntests:1
[  +0.000003] Socket created
[  +0.000007] Socket is bind to 127.0.0.1:3000
[  +0.000104] k_client: Thread running
[  +0.000046] k_client: Performing a simple test: this module will send OK and will wait to receive HELLO from server
[  +0.000103] k_client: Sent HELLO (size 6) to 127.0.0.1 : 4000
[  +0.000096] k_server: Received HELLO (size 6) from 127.0.0.1:3000
[  +0.000009] k_server: Sent OK (size 6) to 127.0.0.1:3000
[  +0.000002] k_client: Received OK (size 6) from 127.0.0.1:4000
[  +0.000001] k_client: All done, terminating client

If you want to have a dynamic view of the kern.log file, use the command tail -f /var/log/kern.log or dmesg -wH

Parameters:

On client, the server ip, server ip and port can be specified as module parameters when loading the module:
sudo insmod udp_client.ko myip=123.12.1.0 myport=2900 destip=123.12.1.2 destport=3000

On server, the server ip and port can be specified as module parameters when loading the module:
sudo insmod udp_server.ko myip=123.12.1.2 port=3000

For the other options, type modinfo module_name.ko in the terminal to get these informations.

The module features 4 operation types:

• PRINT simple HELLO-OK passing
  
• TROUGHPUT checks how many messages a client can send and how many the server can receive
  
• LATENCY checks the average latency
  
• SIMULATION simulates n clients sending messages and counting how many can be received back each second. Prints the result in a file.

u_run.sh and k_run

To make the loading / unloading of modules easier, I also created a script k_run.sh. This script calls make, insmod, wait a command to terminate and call rmmod.

1. Give appropriate executing permission using chmod
2. Run it ./k_run module_name [other optionals parameters]
3. Once unloaded the module, it will wait for enter or ctrl-c to either continue and unload the module or terminate.

If the module is already running and this script is called, the module is unloaded first, recompiled, and loaded again.

emanuele@emanuele-MacBookPro:~/Desktop/Kernel_Modules/Kernel_UDP$ ./run.sh udp_client
Module Successfully complied
Successfully loaded Module
Press enter to remove the module or Ctrl+C to exit...
Closing
Successfuly unloaded Module

Same is with u_run.sh for the user space applications.

from https://github.com/esposem/Kernel_UDP