NG_ETHER_ECHO(4)

📦 version 15.1, in freebsd 14.5, freebsd 15.1, nixpkgs unstable

🦋 ng_ether_echo — the manual page, but make it make sense

okay so real talk: this is NG_ETHER_ECHO(4), a Kernel Interfaces Manual page, and it's literally about the netgraph ether_echo node type. buckle up bestie, it's a short one and it's kinda iconic 💅

✨ NAME ✨

ng_ether_echo — the netgraph ether_echo node type 🎀

🌸 SYNOPSIS 🌸

#include <netgraph/ng_ether_echo.h>

that's it. that's the whole include. slay 💖

🔥 DESCRIPTION 🔥

so the ether_echo node type does exactly one thing and does it gorgeously: it reflects all data and control messages back to the sender. boomerang energy, honestly 🪃

here's the tea though — it assumes the packet is an ethernet frame, and it does not check. not even a little. no vibe check, no validation, nothing. 🙈 and before it echoes anything back, it swaps the source and destination addresses. icon behavior.

it's used for testing and debugging. that's its whole job. main character of the test lab, no cap ✨

🫶 HOOKS 🫶

an ether_echo node accepts any request to connect, regardless of the hook name — like, it does not care at all — as long as the name is unique. that's the one and only condition. unique name or gtfo 💀

💅 CONTROL MESSAGES 💅

okay so this node type supports only the generic control messages. any other control messages? they get reflected back to the sender. it's giving "return to sender" and honestly, respect 🙌

👑 SHUTDOWN 👑

this node shuts down when either of these happens:

  1. it receives an NGM_SHUTDOWN control message 🛑
  2. all hooks have been disconnected 🔌

that's the whole shutdown criteria. no notes. periodt.

🌈 SEE ALSO 🌈

go read them, iykyk 📚

⭐ HISTORY ⭐

the ng_ether_echo node type was implemented in FreeBSD 8.0. vintage. retro. lowkey a classic 🕰️

🎀 AUTHORS 🎀

Julian Elischer <julian@FreeBSD.org> — thank you for your service, king 👑

ok that's the whole page!! every single detail is in there, fr fr — nothing dropped, nothing invented 🧚‍♀️

and for the record: this one came from the Debian edition of the manual, dated December 24, 2008 — so yeah, it's been out here being iconic since before some of us could read 💜 bye bestie, go echo some packets 🦋

📦 where this page comes from