A C program I made to send UDP packets to a specified destination IP and port via raw sockets. This program supports the following:
pthreads(multi-threading).- Specifying a source IP (including spoofing the IP).
- Minimum and maximum payload length (randomized for each packet).
- Randomized source ports (from 10000 to 60000).
- Wait times (intervals) between sending packets on each thread.
- Calculates both the IP Header and UDP Header checksums.
Note - This program does not support packet fragmentation and there's really no point to add that support since that's not what the program is made for.
I am currently learning more about in-depth packet inspection along with learning how (D)DoS attacks work. I made this program and only use it on my local network. I am planning to create a UDP server application that is capable of filtering (D)DoS attacks and blocking them using XDP once detected. This tool will be used to test this server application I will be making. Eventually I will be making software that'll run on my Anycast network that will be capable of dropping detected (D)DoS attacks via XDP on all POP servers.
I used GCC to compile this program. You must add -lpthread at the end of the command when compiling via GCC.
Here's an example:
gcc -g UDP_Sender.c -o UDP_Sender -lpthread
Usage is as follows:
Usage: ./UDP_Sender <Source IP> <Destination IP> <Destination IP> [<Max> <Min> <Interval> <Thread Count>]
Please note that the interval is in microseconds. The Min and Max payloads are in bytes. If you set the interval to 0, it will not wait between sending packets on each thread.
Here's an example:
./UDP_Sender 192.168.80.10 10.50.0.4 27015 1000 1200 1000 3
The above continuously sends packets to 10.50.0.4 (port 27015) and appears from 192.168.80.10 (in my case, spoofed). It sends anywhere from 1000 - 1200 bytes of payload data every 1000 microseconds. It will send these packets from 3 threads.
- Pick source IPs from a configuration file on disk and randomize it for each packet.
I was able to push around 300 mbps (~23K PPS) using this program on my local network until it overloaded my router and VM (I have a lower-end Edge Router). This was with no interval set and using one thread. The VM sending the information had 6 vCPUs and the processor was an older Intel Xeon clocked at 2.4 GHz. This VM was also using around 90 - 95% CPU when having this program running.
I am still fairly new to C and network programming. Therefore, I'm sure there are improvements that can be made. If you see anything that can be improved, please let me know :)
- Christian Deacon (AKA Roy).
- Online resources including Stack Overflow for help with calculating IP/UDP checksums.