nlmsg_multicast(9)

📦 version 7.3.1, in nixpkgs unstable

💌 nlmsg_multicast — a Kernel API Manual moment, brought to you by your fav Unix bestie

okay so bestie, picture this: you're deep in kernel land, the manual you're reading is literally called Kernel API Manual, and the function on the cover is nlmsg_multicast. it's giving "one message, many recipients" and honestly? obsessed. 🦋

📛 NAME (the vibes check)

nlmsg_multicast — multicast a netlink message. that's it. that's the whole thing. one netlink message, spread out to everybody in the group. slay. ✨

📜 SYNOPSIS (the actual signature, no cap)

int nlmsg_multicast (struct sock *sk , struct sk_buff *skb , u32 portid
                     , unsigned int group , gfp_t flags );

look at her. five arguments. main character energy fr 💅

🎀 ARGUMENTS (let's break it down, iykyk)

  • sk — the netlink socket you're spreading messages to. this is the one doing the scattering, like confetti at a party 🎉
  • skb — the netlink message itself, dressed up as a socket buffer. it's the whole point of the operation, the it-girl of the function 💖
  • portid — your own netlink portid. why do we pass it? so you literally don't send the message to yourself. no self-multicasts, we're not doing that today 🙈
  • group — the multicast group id. who's getting the message. the guest list 👑
  • flags — allocation flags. the little settings gremlins that shape how the allocation goes down ⭐

👀 SEE ALSO (the extended universe — every single one, bestie, i did not skip a thing)

kernel file ./include/net/netlink.h plus this entire friend group right here: 🫶

like i said. the whole extended universe. every single one made the list, no gatekeeping 🌈

and that's the page, bestie 💜 this little love letter lives in the ./include/net directory and it's dated October 2026 — go forth and multicast responsibly, mwah 🎀✨

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