__vlan_insert_inner_tag(9)

🎀 NAME 🎀

okay so bestie, welcome to the __vlan_insert_inner_tag(9) page from the Kernel API Manual — it's literally about inner VLAN tag inserting, and yes that's the whole name. iconic. 💅

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✨ SYNOPSIS ✨

the signature is exactly this, no cap:

int __vlan_insert_inner_tag (struct sk_buff *skb , __be16 vlan_proto ,
u16 vlan_tci , unsigned int mac_len );

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🦋 ARGUMENTS 🦋

• skb — the skbuff you're tagging, bestie 🫶
• vlan_proto — the VLAN encapsulation protocol, periodt.
• vlan_tci — the VLAN TCI to insert, lowkey important.
• mac_len — MAC header length including outer vlan headers — don't forget the outer vlan headers, iykyk 💅

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🌸 DESCRIPTION 🌸

so the way this works is: it inserts the VLAN tag into skb as part of the payload at offset mac_len. that's the move. ✨

and it does not change skb->protocol, so this function can be used during receive. main character energy for receive paths, honestly. 🦋

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💅 RETURN 💅

it returns an error if skb_cow_head fails. that's the return vibe — if skb_cow_head fails, you get an error, and that's on periodt. 😭

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👑 SEE ALSO 👑

go touch grass in the Kernel file ./include/linux/if_vlan.h, and also peek at the whole friend group:

• struct vlan_ethhdr(9)
• struct vlan_pcpu_stats(9)
• struct vlan_priority_tci_mapping(9)
• struct vlan_dev_priv(9)
• eth_type_vlan(9)
• __vlan_insert_tag(9)
• vlan_insert_inner_tag(9)
• vlan_insert_tag(9)
• vlan_insert_tag_set_proto(9)
• __vlan_hwaccel_clear_tag(9)
• __vlan_hwaccel_copy_tag(9)
• __vlan_hwaccel_put_tag(9)
• __vlan_get_tag(9)
• __vlan_hwaccel_get_tag(9)
• vlan_get_tag(9)
• vlan_get_protocol_offset_inline(9)
• vlan_get_protocol(9)
• vlan_remove_tag(9)
• skb_vlan_tagged(9)
• skb_vlan_tagged_multi(9)
• vlan_features_check(9)
• compare_vlan_header(9)

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okay bye bestie! 💖 source/version: ./include/linux · date: October 2026 · page: __vlan_insert_inner_tag(9) 🎀✨