tcf_csum_skb_nextlayer(9)

💖 tcf_csum_skb_nextlayer(9) — like, the "get next layer pointer" moment 💖

okay bestie, welcome to the Kernel API Manual ✨ this one lives in section 9 and it's all about tcf_csum_skb_nextlayer — yes that's a mouthful, we're gonna say it together and slay it 🫶

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✨ NAME ✨

tcf_csum_skb_nextlayer — get next layer pointer 🌸 lowkey does exactly what it says on the tin.

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🎀 SYNOPSIS 🎀

void * tcf_csum_skb_nextlayer (struct sk_buff *skb , unsigned int ihl ,
       unsigned int ipl , unsigned int jhl );

that's the whole vibe check: it hands you back a void * 💅

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🦋 ARGUMENTS 🦋

• skb — the sk_buff you're working with, bestie. the packet vessel fr fr 🍓
• ihl — previous summed headers length. that's how much header we already added up 👑
• ipl — complete packet length. the whole thing, not just a lil piece 🌈
• jhl — next header length. the one we're peeking at next 👀

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🔥 DESCRIPTION 🔥

so the actual job: it checks whether the expected next layer is even available inside the sk_buff you passed in. vibe check on the packet's next layer, basically ✨

if it passes, you get the next layer pointer back 🫶 if it doesn't pass, you get NULL — that's it, that's the whole story 😭 no cap.

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💜 SEE ALSO 💜

• Kernel file ./net/sched/act_csum.c — go read the source, iykyk 📖

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ngl this function is short but it eats 💀 don't forget the NULL case, it's giving main character energy and it WILL show up.

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that's the page bestie! 🧚 from <hotpink>./net/sched</hotpink>, in the Kernel API Manual, dated October 2026 — mwah, go check your next layer pointers, ily, periodt 💅💖