__nla_validate(9)

✨ __nla_validate(9) ✨

okay bestie, so this one's from the Kernel API Manual and it's literally the vibe check for netlink attributes 💅 like, it looks at your whole little stream of attrs and goes "mm, is this valid tho?" no cap.

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🌸 NAME 🌸

__nla_validate — Validate a stream of attributes

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🎀 SYNOPSIS 🎀

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

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🦋 ARGUMENTS 🦋

• head — head of attribute stream. like, the very first attr, the main character 👑
• len — length of attribute stream. how much stream we're dealing with, fr fr
• maxtype — maximum attribute type to be expected. the ceiling, the limit, the "don't even try it" 💀
• policy — validation policy. the rulebook bestie, the whole personality of what's allowed
• validate — validation strictness. how picky are we feeling today 🎚️
• extack — extended ACK report struct. where the receipts go if something's off 🧾

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💖 DESCRIPTION 💖

So what it does: it validates all attributes in the specified attribute stream against the specified policy. every single one. she's thorough. ✨

Validation depends on the validate flags passed — see enum netlink_validation for more details on that. and see the documentation of struct nla_policy for more details too, iykyk 📚

Returns 0 on success or a negative error code. slay when it's 0, sad girl hours when it's negative 😭

ngl, the flags really do change how strict she is, so don't just assume one setting fits everything — check enum netlink_validation okay? 🫶

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🌈 SEE ALSO 🌈

Kernel file ./lib/nlattr.c and honestly the whole friend group:

nla_policy_len(9), __nla_parse(9), nla_find(9), nla_strscpy(9), nla_strdup(9), nla_memcpy(9), nla_memcmp(9), nla_strcmp(9), __nla_reserve(9), __nla_reserve_64bit(9), __nla_reserve_nohdr(9), nla_reserve(9), nla_reserve_64bit(9), nla_reserve_nohdr(9), __nla_put(9), __nla_put_64bit(9), __nla_put_nohdr(9), nla_put(9), nla_put_64bit(9), nla_put_nohdr(9), nla_append(9)

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okay that's the whole page, no notes 💅 this gem lives under ./lib, in the October 2026 era, and it's brought to you by __nla_validate(9) — validate your attrs and stay iconic, bestie 🎀💜