ndisc_check_ns_na(9)

💅 ndisc_check_ns_na — Kernel API Manual 💅

okay so bestie, welcome to the ndisc_check_ns_na page — this is a Linux kernel API manual entry, and honestly it's giving "small function, big responsibilities" ✨

---

🌸 NAME 🌸

ndisc_check_ns_na — validate an NS/NA packet and set its transport header 🎀

---

✨ SYNOPSIS ✨

int ndisc_check_ns_na (struct sk_buff *skb );

literally just the one arg, no cap 🫶

---

🦋 ARGUMENTS 🦋

• skb — the skb to validate 💖

---

💜 DESCRIPTION 💜

so what does it actually do? it validates an IPv6 packet for compliance with RFC 4861 sections 7.1.1 (Neighbor Solicitation) and 7.1.2 (Neighbor Advertisement). yes, both sections, she checked them both 💅

if the packet is valid, it sets the skb transport header. slay.

⚠️ heads up bestie: the caller needs to set the skb network header. that part is on you, not her. don't come for her when it's your job 🙈

---

🔥 RETURN 🔥

• 0 — valid NS/NA; the skb transport header has been set. icon behavior, honestly 👑
• -EINVAL — a broken packet was detected, i.e. it violates some internet standard. the packet did NOT pass the vibe check 💀
• -ENOMSG — IP header validation succeeded but it is not an ICMPv6 packet. close, but no 🎀
• -ENODATA — IP+ICMPv6 header validation succeeded but it is not a Neighbor Solicitation or Neighbor Advertisement. so near and yet so far 😭

---

🌈 SEE ALSO 🌈

• Kernel file ./net/ipv6/ndisc_snoop.c — go read the source bestie, it's right there 🧚

---

and that's the whole page!! ty for reading, mwah 💋

sign-off time 🫶 this one's from the ./net/ipv6 crew, dated October 2026, and the page you just read is ndisc_check_ns_na(9) — stay hydrated and always set your network header first 💜✨