netlink_poli...p_add_policy(9)

💖 NAME 💖

netlink_policy_dump_add_policy — bestie, this is the one that adds a policy to the dump ✨

okay so real quick, this whole page lives in the Kernel API Manual and it's literally about one function, netlink_policy_dump_add_policy, so let's get into it 🫶

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🌸 SYNOPSIS 🌸

int netlink_policy_dump_add_policy (struct netlink_policy_dump_state
**pstate , const struct nla_policy *policy , unsigned int maxtype );

yes the signature is iconic, no we're not changing a single character of it 💅

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🎀 ARGUMENTS 🎀

• pstate — the state you're adding to, bestie. heads up: it may be reallocated, and it must be NULL the first time — like, literally NULL, not "kinda empty", NULL NULL 🙈
• policy — the brand new policy you're adding to the dump ✨ main character energy fr
• maxtype — the new policy's max attr type, aka the ceiling, the limit, the maxtype of the situation 👑

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⭐ RETURN ⭐

0 on success 🎉 — and a negative error code otherwise 😭 (so like, if you see a negative number, that's the vibe check failing ngl).

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🦋 DESCRIPTION 🦋

Call this bad boy to allocate a policy dump state and to add policies to it. two jobs, one function, we love a multitasker 💅

And the important bit: this should be called from the dump start callback ⭐ like that's the spot, that's where it goes, no cap.

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💀 NOTE 💀

on failures, any previously allocated state is freed 😭 so like, no leaks, but also no leftovers — it cleans up after itself. periodt.

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🌈 SEE ALSO 🌈

• Kernel file ./net/netlink/policy.c — go read the source, iykyk 📖
• netlink_policy_dump_get_policy_idx(9)
• netlink_policy_dump_loop(9)
• netlink_policy_dump_write_attr(9)
• netlink_policy_dump_write(9)
• netlink_policy_dump_free(9)

the whole little friend group, obsessed honestly 🧚‍♀️

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and that's the page!! shoutout to ./net/netlink for hosting this one, and to October 2026 for the timestamp — catch you in the next dump, bestie 💜🎀✨