UDP Ping Client/Server System

A Rust implementation of a UDP-based Ping server with a Python demo client implementation. The default server UDP port is 444.

Server Features

• Batch processing
• Multi-Threaded
• Supports CPU-pinning
• Authentication using sha256 HMAC
• Linux only (not portable to osX or Windows)

Client Features

• Client with precise timing
• Authentication using sha256 HMAC based token

Installation

1. Clone the repository:

mkdir /opt
cd /opt
git clone https://github.com/rtr-nettest/open-rmbt-udp-ping.git
cd /open-rmbt-udp-ping

Rust server

UDP Ping Server 1.1.0

USAGE:
    udp_server [OPTIONS]

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

OPTIONS:
    -d, --debug      Enable debug logging
    -c, --cpus <CPUS>    CPU cores to use (e.g. 5-8 or 5,6,7,8)
    -s, --seed <SEED>    Sets the HMAC-SHA256 seed
    -p, --port <PORT>    Sets the port to listen on (default: 444)
    -

The debug logging can also be enabled or disabled during runtime using signal SIGUSR1.

cd rust-server

# get rust
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

# get build-essential
apt -y install build-essential

cd rust-server
# build
cargo build --release
# install 
cp target/release/udp_server /usr/local/bin 
# manual start
udp_server -c 0-1 -s topsecret

Format:

• Request: as '!4sI4s8s4s' using: 'RP01', sequence, time_bytes, packet_hash, packet_ip_hash
• Response: as '!4sI' using: 'RR01', sequence
• IP error response: as '!4sI' using: 'RE01', sequence

### Sample debug output
[2025-02-12T08:18:59Z DEBUG udp_server] Received (len=24): 5250303149e8964b67ac5975c44138a21867e72c07f4136c
[2025-02-12T08:18:59Z DEBUG udp_server] HMAC packet: c44138a21867e72c
[2025-02-12T08:18:59Z DEBUG udp_server] HMAC packet matches
[2025-02-12T08:18:59Z DEBUG udp_server] Source address: ::ffff:62.1.2.3 in hex 00000000000000000000ffff3e010203
[2025-02-12T08:18:59Z DEBUG udp_server] HMAC IP: 07f4136c
[2025-02-12T08:18:59Z DEBUG udp_server] Own HMAC IP: 07f4136c
[2025-02-12T08:18:59Z DEBUG udp_server] HMAC IP matches
[2025-02-12T08:18:59Z DEBUG udp_server] Sending response: 5252303149e8964b

Service for systemd

useradd udp_ping
cp systemd/open-rmbt-udp-ping.service /lib/systemd/system/
systemctl daemon-reload
systemctl start open-rmbt-udp-ping
# check status
systemctl status open-rmbt-udp-ping
# enable service  
systemctl enable open-rmbt-udp-ping

Debug logging

Enable or Disable debug logging:

pkill -SIGUSR1 udp_server

Follow log in systemd:

journalctl -fu open-rmbt-udp-ping

Utility

makeToken.py --seed SEED --ip IP

This utility can be used to prepare a token (e.g. Z7QxVTGtS3CGMZ2BzuEkag==)

IP is the IP of the client (source address to the server) SEED is the shared secret to authenticate against the UDP server. In normal operatioon, the shared secret is set in the RMBTControlServer and the same seed is configured on the UDP server.

Client

udp-ping-token.py [-h] --host HOST [--port PORT] --token TOKEN  
udp-ping-token.py [-h] --host HOST [--port PORT] --seed SEED --ip IP

The client can use a prepared TOKEN (first variant of command line options) or generate the token itself, in that case SEED and IP must be provided.

Example:

python3 client/udp_ping_token.py --host udp.example.com --port 444 --seed topsecret  --ip 1.2.3.4

Sample client output

[...]
Response from udp.example.com: seq=11 time=9.960 ms
Response from udp.example.com: seq=12 time=10.548 ms

--- ping statistics ---
12 packets transmitted, 12 received, 0.0% packet loss, time 11079ms
rtt min/avg/max/mdev = 8.074/10.919/16.419/2.133 ms