__nla_parse(9)

📦 version 7.3.1, in nixpkgs unstable

🌸 __nla_parse — Kernel API Manual 💖

okay so bestie, welcome to the little kernel function that turns a raw stream of netlink attributes into something you can actually use ✨ it's called __nla_parse, and the whole manual lives in the Kernel API Manual (the section 9 one, for all the kernel-internals girlies 🎀).

✨ NAME ✨

__nla_parse — Parse a stream of attributes into a tb buffer 🫶

like, literally the whole job description. stream of attrs goes in, tb buffer comes out, slay 💅

🦋 SYNOPSIS 🦋

int __nla_parse (struct nlattr **tb , int maxtype , const struct nlattr
     *head , int len , const struct nla_policy *policy , unsigned int
     validate , struct netlink_ext_ack *extack );

seven arguments, no cap. it's giving "long signature but worth it" energy 😭

💜 ARGUMENTS 💜

  • tb — your destination array, and bestie it needs maxtype+1 elements. count them. do not skimp. the math is mathing 🧮
  • maxtype — the maximum attribute type you expect to see. the ceiling. the limit. the "no attrs above this line" sign 🚧
  • head — head of the attribute stream, aka where the little parade of attributes starts 🌈
  • len — length of the attribute stream. yes queen, tell us how far to read 👑
  • policy — the validation policy. the rulebook. the vibe check for your attributes 📋
  • validate — validation strictness. how hard are we checking? you decide 💅
  • extack — extended ACK pointer. for when you need to send a whole message back about what went wrong 📨

🌸 DESCRIPTION 🌸

so what it does: it parses a stream of attributes and stores a pointer to each attribute into the tb array, reachable via the attribute type. so like, type in → pointer out. iconic lookup behaviour ✨

and the validation? that's controlled by the validate parameter — you set the strictness, it validates accordingly. main character parameter tbh.

it returns 0 on success or a negative error code. so if you get 0, celebrate 🎉 if you get negative, read it as "something went sideways, check your attrs" 😭

🍓 SEE ALSO 🍓

the whole friendship group lives in the kernel file ./lib/nlattr.c — go say hi to all of them:

like a whole group chat of netlink attribute functions and honestly? obsessed 🫶

ngl if you're reading this at 3am with a kernel splat on your screen, hydrate, then re-read the maxtype+1 part 💀🧚

k bye bestie, this page came from ./lib and it's dated October 2026, filed under __nla_parse(9) — go parse something cute ✨💖🎀

📦 where this page comes from