llc_build_and_send_pkt(9)

💅 llc_build_and_send_pkt(9) — the Kernel API Manual, bestie edition 🎀

okay so this is llc_build_and_send_pkt from the Kernel API Manual section 9, and it's giving "the upper layer finally hit send" energy ✨

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✨ NAME ✨

llc_build_and_send_pkt — connection data sending for upper layers 🦋

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🌸 SYNOPSIS 🌸

int llc_build_and_send_pkt (struct sock *sk , struct sk_buff *skb );

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🎀 ARGUMENTS 🎀

• sk — the connection 💜
• skb — the packet to send 📦

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👑 DESCRIPTION 👑

So the way this works: this function gets called when the upper layer wants to send data using connection oriented communication mode, iykyk 🔥

While it's sending data, the connection gets locked, and received frames plus expired timers get queued — no cutting the line, they wait their turn 🧚

Return values, bestie, memorize these:

• 0 — success, slay ✅
• -ECONNABORTED — when the connection already closed 😭
• -EBUSY — when sending data is not permitted in this state, OR when LLC has send an I pdu with p bit set to 1 and is waiting for it's response 💀

fr fr important: this function always consumes a reference to the skb — no cap, don't go freeing that thing yourself afterwards 🙈

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🌈 SEE ALSO 🌈

Kernel file ./net/llc/llc_if.c, plus these iconic siblings:

• llc_establish_connection(9)
• llc_send_disc(9)

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and that's the whole vibe check 💖 this page lives in ./net/llc, stamped October 2026 — go forth and send those packets, main character 🫶✨