vti6_tnl_lookup(9)

📦 version 7.3.1, in nixpkgs unstable

💅 vti6_tnl_lookup — bestie's guide to the Kernel API Manual ✨

okay so picture this: you're deep in the kernel, you've got a struct net, you've got some IPv6 addresses, and you just need to find the tunnel. that's it. that's the whole vibe. welcome to vti6_tnl_lookup(9), straight out of the Kernel API Manual 🎀

🌸 NAME 🌸

vti6_tnl_lookup — fetch tunnel matching the end-point addresses 🦋

like, it goes and gets you the tunnel whose endpoints line up with what you asked for. no cap.

✨ SYNOPSIS ✨

struct ip6_tnl * vti6_tnl_lookup (struct net *net , const struct
in6_addr *remote , const struct in6_addr *local );

she takes three args and hands you back a struct ip6_tnl *. iconic signature tbh 💅

🫶 ARGUMENTS 🫶

  • net — network namespace 🌐 — the whole little universe the tunnel lives in
  • remote — the address of the tunnel exit-point 🚪 — where the traffic peaces out
  • local — the address of the tunnel entry-point 🏠 — where it all starts

🔥 RETURN 🔥

okay so three possible outcomes, main character energy all around:

  • tunnel matching given end-points, if found 👑 — the slay scenario
  • else the fallback tunnel, if its device is up 🌈 — runner-up but still valid
  • else NULL 💀 — bestie... nothing. it's giving empty search results

⭐ SEE ALSO ⭐

Kernel file ./net/ipv6/ip6_vti.c 📁 and honestly the whole friend group:

ngl the fallback branch is lowkey the sneaky part — it's not just "did we find a match", it also checks that the fallback's device is up before handing it to you. vibe check passed or you get NULL. 🙈

and that's the page, bestie! 🍓 brought to you from the source path ./net/ipv6, dated October 2026, filed under vti6_tnl_lookup(9) in the Kernel API Manual — mwah, go read the source, ily 🧚💜

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