rhine_get_vlan_tci(9)

💅 rhine_get_vlan_tci(9) — bestie edition 🌸

okay so this is a page from the Kernel API Manual and it's about one (1) little function that pulls a VLAN TCI out of your Rx buffer. it's giving "small but essential" energy and honestly? we're obsessed 💖

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✨ NAME ✨

rhine_get_vlan_tci — extract TCI from Rx data buffer 👑

like literally, that's the whole job. it reaches into your receive data buffer and pulls the TCI out. no cap.

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🦋 SYNOPSIS 🦋

u16 rhine_get_vlan_tci (struct sk_buff *skb , int data_size );

it returns a u16 (that's the TCI, bestie 🎀) and it takes two things. that's it. that's the whole signature.

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🎀 ARGUMENTS 🎀

• skb — pointer to sk_buff 💫 your classic socket buffer pointer, main character of the networking world, we stan
• data_size — the used data area of the buffer, including the CRC ⭐ don't forget the CRC is in there, it's part of the count, iykyk

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🌈 DESCRIPTION 🌈

so here's the vibe check 🧚 — if hardware VLAN tag extraction is enabled, and the chip says "hey this is a 802.1Q packet", then the extracted 802.1Q header lands in a very specific spot:

• it's 2 bytes TPID + 2 bytes TCI (that's the header, 4 bytes total, cute)
• it's 4-byte aligned
• and it comes following the CRC 🔥

so like. TPID, TCI, aligned to 4, sitting right after the CRC. that's the whole layout. periodt. 💅

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👑 SEE ALSO 👑

go read the kernel file ./drivers/net/ethernet/via/via-rhine.c — it's the source of truth, fr fr 📖 and while you're in there, these are all siblings / besties in the same driver family 🫶

• rhine_set_cam(9)
• rhine_set_vlan_cam(9)
• rhine_set_cam_mask(9)
• rhine_set_vlan_cam_mask(9)
• rhine_init_cam_filter(9)
• rhine_update_vcam(9)

all of them. every single one. no skipping 💀

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mwah 💜 that's the page!! huge shoutout to the ./drivers/net/ethernet/via crew for hosting this whole thing and to October 2026 for the timestamp — slay, see u next revision 🌟