__iptfs_iphlen(9)

📦 version 7.3.1, in nixpkgs unstable

💅 __iptfs_iphlen (9) — Kernel API Manual

okay so bestie, welcome to __iptfs_iphlen(9), a tiny little function from the kernel API manual that is genuinely doing the most for such a small name. she's short, she's sweet, she tells you how big an IP header is. icon behavior, honestly.

✨ NAME ✨

__iptfs_iphlen — returns the v4/v6 header length, and she does it by peeking at packet data. that's it, that's the whole job 🎀

🌸 SYNOPSIS 🌸

u32 __iptfs_iphlen (u8 *data );

🦋 ARGUMENTS 🦋

  • data — pointer at the octet that holds the version nibble. like, that specific byte, the one with the version vibe living in its top bits 🫶

💖 DESCRIPTION 💖

so the version in data has already been checked and confirmed valid, meaning it's either 4 or 6. no cap, that validation already happened before you got here — this function is not out here doing vibe checks on untrusted input, she trusts you 💅

⭐ RETURN ⭐

she gives you back the IP header size, based on the IP version. simple. clean. main character energy 👑

🌈 SEE ALSO 🌈

the whole friend group, fr fr — the kernel file ./net/xfrm/xfrm_iptfs.c plus:

ngl this page is like three sentences long and i respect that so much. no filler, no yapping, just header length 🍓

and that's the whole thing bestie!! this came out of ./net/xfrm and it's dated October 2026 — stan a tidy little kernel manual page 💜✨🧚

📦 where this page comes from