TCP Echo Server

This is a simple TCP echo server implemented using the neco library, which simplifies concurrent I/O and network programming. The server echoes back every string received from connected clients.

Features

• coroutines for handling of multiple clients (no fork or thread for every client)
• Automatically disconnects stale clients after a hardcoded timeout period (5 seconds)
• Protects against clients sending excessive data by enforcing a maximum data limit
• Every network call use neco_read_dl() and neco_write_dl() (with deadlines)

Usage

Can be used as a simple TCP target for your Load Balancer TCP checks.

You must specify listening interface and port number. There is no default value:

$ ./necoecho 0.0.0.0 9000
listening at 0.0.0.0:9000

Compilation

Preparation:

# Debian12/Ubuntu
apt-get -y install build-essential git
git clone --recursive https://github.com/pawlakus/necoecho.git

MacOS/darwin:

make

Alpine Linux 3.18, muslc statically linked

CPPFLAGS='-D_GNU_SOURCE -static' make

Ubuntu 20.04

CPPFLAGS='-Wl,--no-as-needed -ldl' make

Ubuntu 22.04

make

Debian 12

make

Run as non-root on any port (Linux)

setcap cap_net_bind_service=ep necoecho