nf_nat_used_tuple_new(9)

💅 nf_nat_used_tuple_new(9) — from the Kernel API Manual bestie ✨

okay so picture this: it's giving conntrack gatekeeping era, and this little function is the bouncer at the door 🎀

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✨ NAME ✨

nf_nat_used_tuple_new — the vibe check that tells you whether a to-be-inserted conntrack is about to collide with an existing entry 💥

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🌸 SYNOPSIS 🌸

bool nf_nat_used_tuple_new (const struct nf_conntrack_tuple *tuple ,
const struct nf_conn *ignored_ct );

like yes bestie it returns a bool, we love a yes-or-no icon 👑

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🦋 ARGUMENTS 🦋

• tuple — the proposed NAT binding, i.e. the fit we're trying to serve 🔥
• ignored_ct — our own (unconfirmed) conntrack entry, the one we're lowkey side-eyeing past 🙈

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💜 DESCRIPTION 💜

So it's literally the same as nf_nat_used_tuple, except it also checks for that rare clash in the reverse direction 🫶 no cap, that's the whole tea.

⚠️ Heads up bestie: this should only be called when tuple has not been altered — meaning ignored_conntrack will not be subject to NAT. Do not come for this function's wig by calling it at the wrong moment, fr fr 😭

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⭐ RETURN ⭐

Returns true if the proposed NAT mapping collides with an existing entry 💀 (and by implication, not-true when it's all clear 🌈).

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🌟 SEE ALSO 🌟

• Kernel file ./net/netfilter/nf_nat_core.c
• nf_nat_used_tuple(9)

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mwah 💋 that's the whole page, stream it, screenshot it, send it to the group chat — this one came straight from the kernel tree at ./net/netfilter, dated October 2026, and it slayed ✨🎀💖