skb_reserve(9)

🎀 NAME 🎀

okay so bestie, welcome to skb_reserve(9) — part of the Kernel API Manual — and it does exactly one thing: it adjusts headroom. That's it. That's the whole gig. ✨

skb_reserve — adjust headroom 💅

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🌸 SYNOPSIS 🌸

void skb_reserve (struct sk_buff *skb , int len );

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🦋 ARGUMENTS 🦋

• skb — the buffer you're messing with 💖 (the one being altered)
• len — how many bytes you're moving 🚶‍♀️

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⭐ DESCRIPTION ⭐

Okay so picture this: you've got an empty sk_buff, right? skb_reserve bumps up its headroom by reducing the tail room. Give with one hand, take from the other, that's the vibe. 🔥

💀 but like… this is only allowed for an empty buffer. Empty. That's the rule. Don't be out here reserving on a non-empty buffer, that's not the move. periodt.

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👑 SEE ALSO 👑

the whole extended skb family tree, no cap 🧚 — starting with the kernel file ./include/linux/skbuff.h:

• skb checksums(9), skb_frag_size(9), skb_frag_size_set(9), skb_frag_size_add(9), skb_frag_size_sub(9), skb_frag_must_loop(9), skb_frag_foreach_page(9)
• struct skb_shared_hwtstamps(9), dataref and headerless skbs(9), Basic sk_buff geometry(9), struct sk_buff(9), skb_pfmemalloc(9)
• skb_dst(9), skb_dstref_steal(9), skb_dstref_restore(9), skb_dst_set(9), skb_dst_set_noref(9), skb_dst_is_noref(9), skb_napi_id(9)
• skb_unref(9), kfree_skb(9), alloc_skb(9), skb_fclone_busy(9), alloc_skb_fclone(9), skb_pad(9)
• skb_queue_empty(9), skb_queue_empty_lockless(9), skb_queue_is_last(9), skb_queue_is_first(9), skb_queue_next(9), skb_queue_prev(9)
• skb_get(9), skb_cloned(9), skb_header_cloned(9), __skb_header_release(9), skb_shared(9), skb_share_check(9), skb_unshare(9)
• skb_peek(9), __skb_peek(9), skb_peek_next(9), skb_peek_tail(9), skb_queue_len(9), skb_queue_len_lockless(9)
• __skb_queue_head_init(9), skb_queue_splice(9), skb_queue_splice_init(9), skb_queue_splice_tail(9), skb_queue_splice_tail_init(9)
• __skb_queue_after(9), __skb_queue_head(9), __skb_queue_tail(9), __skb_dequeue(9), __skb_dequeue_tail(9), skb_len_add(9)
• __skb_fill_netmem_desc(9), skb_fill_page_desc(9), skb_fill_page_desc_noacc(9), skb_headroom(9), skb_tailroom(9), skb_availroom(9), skb_tailroom_reserve(9)
• skb_reset_transport_header_careful(9), skb_set_transport_header_careful(9), pskb_trim_unique(9), skb_orphan(9), skb_orphan_frags(9), __skb_queue_purge_reason(9)
• netdev_alloc_frag(9), netdev_alloc_skb(9), __dev_alloc_pages(9), __dev_alloc_page(9), dev_page_is_reusable(9), skb_propagate_pfmemalloc(9)
• skb_frag_off(9), skb_frag_off_add(9), skb_frag_off_set(9), skb_frag_off_copy(9), skb_frag_net_iov(9), skb_frag_page(9), skb_frag_netmem(9)
• skb_frag_address(9), skb_frag_address_safe(9), skb_frag_phys(9), skb_frag_page_copy(9), __skb_frag_dma_map(9)
• skb_clone_writable(9), skb_cow(9), skb_cow_head(9), skb_padto(9), __skb_put_padto(9), skb_put_padto(9)
• skb_linearize(9), skb_has_shared_frag(9), skb_linearize_cow(9), skb_postpull_rcsum(9), skb_postpush_rcsum(9), skb_push_rcsum(9), pskb_trim_rcsum(9)
• skb_needs_linearize(9), skb_get_timestamp(9), skb_data_move(9), skb_postpull_data_move(9), skb_postpush_data_move(9)
• skb_complete_tx_timestamp(9), skb_tstamp_tx(9), skb_tx_timestamp(9), skb_complete_wifi_ack(9)
• skb_checksum_complete(9), struct skb_ext(9), skb_checksum_none_assert(9), skb_head_is_locked(9)

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🌸 that's the whole page, bestie — go reserve some headroom responsibly 💜

🫶 mwah, this one's from ./include/linux, dated October 2026, page skb_reserve(9). iykyk 💅