__nla_put_64bit(9)

📦 version 7.3.1, in nixpkgs unstable

💖 __nla_put_64bit — Kernel API Manual energy ✨

okay so bestie, welcome to the group chat where we learn how to shove a netlink attribute into a socket buffer and align it. yes, it's a kernel API manual page, no it's not boring, and yes you're gonna slay this. 💅

✨ NAME ✨

__nla_put_64bit — add a netlink attribute to a socket buffer and align it 🎀

(that's the whole vibe. add attribute. align it. done. iconic.)

🌸 SYNOPSIS 🌸

void __nla_put_64bit (struct sk_buff *skb , int attrtype , int attrlen ,
       const void *data , int padattr );

look at that signature. gorgeous. returns void, which lowkey means "no take-backs, no error codes, you're on your own" 😭

🦋 ARGUMENTS 🦋

  • skb — the socket buffer you're adding the attribute to. this is the main character, the canvas, the whole venue 🫶
  • attrtype — the attribute type. literally just, what kind of attribute is this 💫
  • attrlen — length of the attribute payload. how many bytes of Actual Content we're rocking ✨
  • data — head of the attribute payload. i.e. where the good stuff starts 🍓
  • padattr — attribute type for the padding. yes the padding gets its own type, she has her own identity, respect her 👑

🔥 DESCRIPTION 🔥

so here's the tea: the caller — that's you, bestie — is responsible for making sure the skb actually has enough tailroom for the attribute header and the payload.

⚠️ read that again. you make sure there's enough tailroom. nobody's checking for you. this function is not your mom, it's not doing a vibe check on your buffer. no cap. 💀

that's it. that's the whole description. short, sweet, and it will absolutely bite you if you skip the tailroom part 🙈

🌈 SEE ALSO 🌈

the whole ./lib/nlattr.c friend group, and honestly they're all iconic:

so many functions. so many underscores. the __ prefix is giving "i'm the internal one, use my public sibling if you're normal" 🧚

anyway that's the page!! go forth, check your tailroom, and remember: come from ./lib, stay for the padding ✨

mwah 💖 — signed, your favorite kernel manual, dated October 2026, shipped from ./lib, and yes the footer still says __nla_put_64bit(9) because branding is forever 👑

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