mesh_rmc_check(9)

🦋 mesh_rmc_check(9) — the kernel API manual, bestie edition 🦋

Okay so this is a page from the Kernel API Manual (man section 9, kernel internals, very "I know things" energy) and it's all about mesh_rmc_check. Let's get into it ✨

---

🌸 NAME 🌸

mesh_rmc_check — check a frame in the recent multicast cache and add it if it's absent. That's the whole vibe check in one line, no cap 💅

---

✨ SYNOPSIS ✨

int mesh_rmc_check (struct ieee80211_sub_if_data *sdata , const u8 *sa ,
       struct ieee80211s_hdr *mesh_hdr );

Look at that signature, she's iconic 👑

---

🎀 ARGUMENTS 🎀

• sdata — the interface. Like, the actual wireless sub-if-data situation you're working with 🫶
• sa — the source address. Where the frame says it came from 💌
• mesh_hdr — the mesh header. The mesh-y header part, obviously 🌈

---

🔥 RETURN 🔥

• Returns 0 if the frame is not in the cache.
• Nonzero otherwise (i.e. it was already there, bestie, we've seen this one 🫣).

So yeah: 0 means "new to me", anything else means "already clocked it" ⭐

---

💖 DESCRIPTION 💖

So here's the tea ☕ — this function checks, using the source address and the mesh sequence number, whether we've received this exact frame lately.

If the frame is not in the cache, it gets added to it. Boom, now it's cached. That's literally it and honestly? Slay 💅

It's giving "have I seen this already" energy, but for mesh frames. Main character behavior fr fr 🧚

---

🌟 SEE ALSO 🌟

• Kernel file ./net/mac80211/mesh.c — the home base for all of this 🏠
• mesh_matches_local(9)
• mesh_peer_accepts_plinks(9)
• mesh_accept_plinks_update(9)
• ieee80211_fill_mesh_addresses(9)
• ieee80211_new_mesh_header(9)

All of these are lowkey in the same friend group, go read them too 🫶

---

Alright bestie, that's the whole page 💜 big kisses from ./net/mac80211, dated October 2026 — go forth and cache those frames responsibly 🎀✨