__vlan_insert_tag(9)

📦 version 7.3.1, in nixpkgs unstable

✨ __vlan_insert_tag — regular VLAN tag inserting 🎀

okay bestie, so this one is a kernel API manual page (section 9, the kernel API one, iykyk) and honestly? it's giving "small function, big job" 💅 let's get into it.

🌸 SYNOPSIS 🌸

int __vlan_insert_tag (struct sk_buff *skb , __be16 vlan_proto , u16
vlan_tci );

literally just one call, three things in, an int out. iconic behavior 🫶

💖 ARGUMENTS 💖

  • skb — the skbuff you're tagging, bestie. this is the one getting the glow-up ✨
  • vlan_proto — the VLAN encapsulation protocol. that's the __be16 one, don't mix it up 🙈
  • vlan_tci — the VLAN TCI to insert. it's a u16, so keep it in its lane 🎀

🌈 DESCRIPTION 🌈

So what does it do? It inserts the VLAN tag into skb as part of the payload 📦 — that part matters, ok?

And the key detail, no cap: it does not change skb->protocol, which is exactly why this function can be used during receive 🔥 like, that's the whole point of the underscore-prefix version, iykyk.

⭐ RETURN ⭐

Returns an error if skb_cow_head fails. that's it, that's the deal 💀

Heads up bestie: if skb_cow_head fails, you get an error back — so check that return value, fr fr 🙏

🦋 SEE ALSO 🦋

The kernel file for all this lives at ./include/linux/if_vlan.h, and here's the whole friend group 👑 :

like, that's a whole squad 🧚💜

okay that's the page!! this one comes to you from the kernel API manual, source path ./include/linux, dated October 2026 🌸 — and that's the whole __vlan_insert_tag(9) situation, mwah 💋✨

📦 where this page comes from