net-tools

A collection of ICMPv4 network utilities as an alternative to standard system commands (ping, ...).

Code Style

• Allman braces: opening and closing braces each on their own line
• Yoda conditions: constant on the left (e.g. 0 == val, NULL != ptr)
• C99 compliant
• Tabs only, width 4
• snake_case for functions and variables, SCREAMING_SNAKE_CASE for macros
• System includes, then a blank line, then local includes
• Variable declarations aligned with tabs within the function body
• Static helper functions are forward-declared at the top of the file and defined after the main public function
• Function definitions (not forward declarations or prototypes) have a newline between the return type and the function name
• Line continuations are indented 2 tabs past the base scope indentation

Dependencies

• clang (C99)
• make
• bash (configure script)
• POSIX-compliant OS
• libc

For tests only:

• criterion

Binaries

ft_ping

Alternative to inetutils ping. Sends ICMPv4 ECHO_REQUEST packets to network hosts and reports RTT statistics. Requires root (raw socket).

ft_ping - Send ICMP ECHO_REQUEST to network hosts
Usage: ft_ping [options] <destination>

Options:
  -h, --help                Display this help and exit
  -V, --version             Display version information and exit
  -v, --verbose             Verbose output
  -q, --quiet               Quiet mode (only show summary)
  -c, --count      <NUM>    Stop after sending N packets
  -i, --interval   <SEC>    Wait N seconds between packets
  -t, --ttl        <TTL>    Set Time To Live
  -s, --size       <SIZE>   Packet size in bytes
  -W, --timeout    <SEC>    Timeout for replies in seconds
  -w, --deadline   <SEC>    Exit after N seconds regardless of packets sent/received
  -f, --flood               Flood mode
  -M, --dont-fragment       Set the Don't Fragment bit

Modules

libicmp

Handles everything ICMP at the socket level: open a raw socket, build and send echo requests, receive and parse replies. No loop, no display. Just a clean interface over the kernel socket.

src/cli

Shared CLI parsing layer used by all binaries. Provides a generic getopt wrapper and primitive parsers (int, float) that each binary plugs into.

src//cli

Per-binary argument parsing. Defines the accepted options, validates them, and fills the binary-specific config struct.

src/ping/core

Drives the ping session for one destination. ping_run() creates the socket and calls ping_one() for each destination. ping_one() sets up state, runs the loop, and prints the summary. ping_loop() uses select() to wait for packets and reacts to send/stop flags. ping_send_one() builds the payload and calls libicmp. ping_callback() handles incoming replies and errors.

src/ping/scheduler

Manages timing and signals. Installs SIGALRM (triggers send) and SIGINT (triggers stop). Arms a one-shot timer via setitimer() after each send. Signal handlers only write a flag -- the loop does the actual work.

src/ping/tracker

A 128-slot circular buffer indexed by (seq % 128). Records when each packet was sent and marks it when a reply arrives. Used to compute RTT and detect duplicates.

src/ping/stats

Accumulates RTT samples (min, max, sum, sum of squares) in nanoseconds. Computes min/avg/max/mdev in milliseconds on demand.

src/ping/output

All user-facing output: the opening line, per-packet lines, ICMP error messages, the final statistics summary, and flood mode dots.

License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.

Authors

• lohhiiccc - GitHub

See Also

• RFC 792 - Internet Control Message Protocol
• RFX 1071 - Computing the Internet Checksum
• libicmp
• inetutils