ixgbe_mta_vector(9)

📦 version 7.3.1, in nixpkgs unstable

💅 ixgbe_mta_vector — a kernel API manual page (section 9, bestie)

Okay so first things first: this is ixgbe_mta_vector(9), living its best life in the Kernel API Manual, section 9. Yes, the function is literally named ixgbe_mta_vector and yes we're gonna get into it. 🫶

✨ NAME ✨

ixgbe_mta_vector — Determines bit-vector in multicast table to set

Like, that's the whole job. It figures out which bit-vector in the multicast table needs setting. Iconic, honestly. 👑

🌸 SYNOPSIS 🌸

int ixgbe_mta_vector (struct ixgbe_hw *hw , u8 *mc_addr );

That's it. That's the whole call. Two args, one int coming back at you. Slay. ✨

🎀 ARGUMENTS 🎀

  • hw — pointer to hardware structure. Like, the actual hardware bestie. You're handing it over. 💖
  • mc_addr — the multicast address. The whole reason we're here.

🦋 DESCRIPTION 🦋

So here's the tea, bestie. ☕ This function extracts the 12 bits from a multicast address — yes, exactly 12 — to determine which bit-vector to set in the multicast table. That's the whole vibe check.

The hardware uses 12 bits, taken from incoming rx multicast addresses, to determine the bit-vector to check in the MTA. And because the universe loves options, there are 4 combinations of those 12-bits the hardware could be using — and which one it uses is set by the MO field of the MCSTCTRL.

And when does the MO field get set? During initialization, to mc_filter_type. So it's already decided before you even show up. Main character energy from the MO field, honestly. 💀

Ngl, the important part: you don't pick the combination. It was chosen at init time. You just extract the 12 bits and go. Periodt.

🔥 SEE ALSO 🔥

Kernel file ./drivers/net/ethernet/intel/ixgbe/ixgbe_common.c — that's where this lives, go say hi. 🌈

And then the entire friend group, in order, no cap:

Okay that's genuinely the whole page, no filler, we ate and left no crumbs. 🍓

Shoutout to the source this came from, ./drivers/net/ethernet/intel/i..., dated October 2026 — mwah, ily, thanks for the lore. 💖✨

📦 where this page comes from