batadv_check_unicast_packet(9)

📦 version 7.3.1, in nixpkgs unstable

💅 batadv_check_unicast_packet(9) 💅

okay so bestie, welcome to the Kernel API Manual — this one's a little function from the kernel's batman-adv corner, and honestly it's giving security-guard-at-the-door energy ✨. It's literally just checking packets before anyone lets them in. Let's go 🫶

✨ NAME ✨

batadv_check_unicast_packet — check for malformed unicast packets 🕵️‍♀️

🌸 SYNOPSIS 🌸

int batadv_check_unicast_packet (struct batadv_priv *bat_priv , struct
       sk_buff *skb , int hdr_size );

🎀 ARGUMENTS 🎀

  • bat_priv — the bat priv that's holding all the mesh interface information, like the group chat admin who knows every member 🫶
  • skb — the packet we're checking, the actual main character of this whole story 📦
  • hdr_size — size of the header to pull, i.e. how many bytes we're yoinking off the front 👑

🦋 DESCRIPTION 🦋

So what does it actually do? It checks for a short header and bad addresses in the given packet. That's it, that's the vibe check ✅. If the header's too short or the addresses are sus, it's not passing — no cap.

💜 RETURN 💜

Here's the tea, and it's giving very specific negative values:

  • a negative value when the check fails — and which negative value depends on the reason 👀
  • 0 otherwise, aka everything's fine, we love to see it 💖

The negative values, one by one, because every reason has its own little label:

  • -ENODATA — for a bad header 🙈
  • -EBADR — for a broadcast destination or source, which is lowkey not what we asked for 📢
  • -EREMOTE — for a non-local (other host) destination, like it's cute but it's not ours 🚫

🔥 SEE ALSO 🔥

Kernel file ./net/batman-adv/routing.c and its whole friend group (this is a long list, bestie, but we're not skipping a single one, periodt):

okay that's the whole page, ily for reading it all 💕 sign-off time: this one lives in ./net/batman-adv, it's dated October 2026, and it's page batadv_check_unicast_packet(9) of the Kernel API Manual — stamped and delivered 🎀🦋✨

📦 where this page comes from