inet6_lookup_reuseport(9)

💅 inet6_lookup_reuseport(9) — like, the kernel API manual one, section 9 bestie ✨

okay so picture this: it's a Kernel API Manual page, section 9, and the whole thing is about inet6_lookup_reuseport — that's the function whose whole personality is "execute reuseport logic on AF_INET6 socket if necessary." slay. let's get into it 🎀

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✨ NAME ✨

inet6_lookup_reuseport — executes the reuseport logic on an AF_INET6 socket if necessary. lowkey does what it says on the tin, no notes 💅

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🌸 SYNOPSIS 🌸

struct sock * inet6_lookup_reuseport (const struct net *net , struct
sock *sk , struct sk_buff *skb , int doff , const struct in6_addr *saddr
, __be16 sport , const struct in6_addr *daddr , unsigned short hnum ,
inet6_ehashfn_t *ehashfn );

like yes that's a lot of parameters, but she ate and left no crumbs 👑

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🦋 ARGUMENTS 🦋

• net — the network namespace. that's her world, her main character setting ✨
• sk — an AF_INET6 socket. important vibe check: it must be in TCP_LISTEN state for TCP, or TCP_CLOSE for UDP. no exceptions bestie, that's the rule 🚨
• skb — the context for a potential SK_REUSEPORT program. it's giving "here's where the program might happen" 🫶
• doff — the header offset. just an offset. iconic in its simplicity 💜
• saddr — source address 📬
• sport — source port 🔢
• daddr — destination address 📭
• hnum — destination port, and bestie it's in host byte order — write that down, that detail matters fr fr 🍓
• ehashfn — the hash function used to generate the fallback hash. the fallback hash's fallback bestie, we love a safety net 🌈

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⭐ RETURN ⭐

so what comes back? two possibilities, and honestly both are valid:

• NULL if sk doesn't have SO_REUSEPORT set 😭 (like it literally didn't opt in, so)
• otherwise, a pointer to the selected sock or an error 🔥

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👑 SEE ALSO 👑

• Kernel file ./net/ipv6/inet6_hashtables.c — go read her, she's got the lore 📖✨

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💀 reminder bestie: the state requirements on sk are not a suggestion — TCP_LISTEN for TCP, TCP_CLOSE for UDP. don't be the person who ignores it 🙈

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and that's the whole page 🧚 from ./net/ipv6, dated October 2026 — mwah, periodt, inet6_lookup_reuseport(9) out 💖