This is a rather basic implementation of the ping command in C. It was created for learning more about raw sockets and how ping works (and for fun).

Features:

• Cross-platform: can compile and run on Windows, Linux, macOS, *BSD
• Supports IPv6
• Displays time with microsecond precision

To build ping you will need a C89 compiler and CMake.

After you cloned this repo run the following commands to build an executable:

cd ping
mkdir build && cd build
cmake ../ -G "Unix Makefiles"
make

Example usage:

$ ./ping google.com
PING google.com (XXX.XXX.XXX.XXX)
Received reply from XXX.XXX.XXX.XXX: seq=0, time=103.307 ms
Received reply from XXX.XXX.XXX.XXX: seq=1, time=91.200 ms
Received reply from XXX.XXX.XXX.XXX: seq=2, time=103.080 ms
Received reply from XXX.XXX.XXX.XXX: seq=3, time=94.531 ms
Received reply from XXX.XXX.XXX.XXX: seq=4, time=92.204 ms
^C

The program will run indefinitely until you interrupt it.

Note: the use of raw sockets usually requires administrative privileges. One of the ways to overcome this is to use sudo. However, running programs as root is very dangerous and can potentially damage your system! Also: DO NOT run random code from the internet as root! You should look into other options instead, such as Capabilities on Linux or using a Docker container or a VM.

The scripts directory contains a couple of scripts to aid debugging:

• capture.sh - captures ICMP traffic with tcpdump and saves it to ping.pcap
• dump.sh - prints the contents of ping.pcap in a nice form (tcpdump may actually display helpful errors there, like a miscalculated checksum)