cn_netlink_send_mult(9)

💌 cn_netlink_send_mult — the kernel-API-manual glow-up ✨

okay bestie, so this one is a kernel API manual page for cn_netlink_send_mult(9), and honestly it's giving "send a message to your group chat but make it netlink" 🫶. Let's get into it.

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🌸 NAME 🌸

cn_netlink_send_mult — sends a message to the specified groups. that's it, that's the whole vibe 💅

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✨ SYNOPSIS ✨

int cn_netlink_send_mult (struct cn_msg *msg , u16 len , u32 portid ,
u32 group , gfp_t gfp_mask , netlink_filter_fn filter , void
*filter_data );

seven arguments, zero chill. let's meet them 👑

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🎀 ARGUMENTS 🎀

• msg — the message header (with the attached data riding along with it, iykyk).
• len — the number of msg to be sent. yes, number of msg. that's the wording, we respect it.
• portid — the destination port. if it's non-zero, the message goes to that given port, and bestie, that port should be set to the original sender. lowkey important 🫶
• group — the destination group. here's the tea ☕: if portid and group are zero, then the appropriate group gets searched through all registered connector users, and the message is delivered to the group that was created for the user with the same ID as in msg. if group is not zero, then the message goes straight to that specified group. slay, simple.
• gfp_mask — the GFP mask. iconic, no notes.
• filter — the filter function that gets used at the netlink layer.
• filter_data — the filter data that gets supplied to the filter function. matching set, we love to see it 💖

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🦋 DESCRIPTION 🦋

so here's the thing: it can be safely called from softirq context ✨ — but it may silently fail under strong memory pressure 😭. not me getting ghosted by my own syscall.

and if there are no listeners for the given group, then -ESRCH can be returned. fr fr, know the error code before you come for her 💀

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🌈 SEE ALSO 🌈

• the kernel file ./include/linux/connector.h
• cn_add_callback(9)
• cn_del_callback(9)
• cn_netlink_send(9)

the whole connector cinematic universe, we stan 🎬👑

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💡 friendly reminder: every flag, number, path and error code above is exactly as the original page says it. no invented lore, no cap.

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mwah 💋 this page lives in ./include/linux and is dated October 2026 — so go forth, call your groups, filter your data, and remember: softirq-safe but memory-pressure-shy. bye bestie!! 💜🦋✨