__pskb_pull_tail(9)

🌸 NAME 🌸

Okay bestie, welcome to __pskb_pull_tail(9) from the Kernel API Manual — yes, we're in kernel API land, stay close 💅

The name is literally the job: advance tail of skb header. That's it. That's the whole assignment. ✨

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✨ SYNOPSIS ✨

void * __pskb_pull_tail (struct sk_buff *skb , int delta );

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🎀 ARGUMENTS 🎀

• skb — the buffer to reallocate, bestie. That's the one we're working on.
• delta — the number of bytes to advance the tail by. Yes, exactly that many. 🔥

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💅 DESCRIPTION 💅

Okay so this function only makes sense on a fragmented sk_buff — like, if it's not fragmented, this is not the vibe. It expands the header by moving its tail forward and copying the necessary data over from the fragmented part. Very “make it fit” energy. 🫶

⚠️ HUGE caveat, no cap: the sk_buff MUST have a reference count of 1. Not 2, not “basically 1,” not “it's fine probably.” 1. Periodt. 👑

If the pull failed, it returns NULL — and sk_buff does not change. If it succeeded, you get the value of the new tail of skb. Slay. 💖

🚨 Another important one: all the pointers pointing into the skb header may change, and they must be reloaded after you call this function. Do not reuse stale pointers, bestie, I am begging. 😭

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🦋 SEE ALSO 🦋

Kernel file ./net/core/skbuff.c — here's the whole iconic friend group:

• drop_reasons_register_subsys(9), drop_reasons_unregister_subsys(9), skb_panic(9), napi_skb_cache_get_bulk(9), __build_skb(9), build_skb_around(9), __napi_build_skb(9), napi_build_skb(9), __alloc_skb(9), __netdev_alloc_skb(9), napi_alloc_skb(9), skb_pp_cow_data(9), skb_pp_frag_ref(9), __kfree_skb(9), sk_skb_reason_drop(9), skb_tx_error(9), consume_skb(9), __consume_stateless_skb(9), napi_consume_skb(9), alloc_skb_for_msg(9), skb_morph(9), skb_copy_ubufs(9), skb_clone(9), skb_copy(9), __pskb_copy_fclone(9), pskb_expand_head(9), skb_expand_head(9), skb_copy_expand(9), __skb_pad(9), pskb_put(9), skb_put(9), skb_push(9), skb_pull(9), skb_pull_data(9), skb_trim(9), skb_copy_bits(9), skb_store_bits(9), skb_zerocopy(9), skb_dequeue(9), skb_dequeue_tail(9), skb_queue_purge_reason(9), skb_rbtree_purge(9), skb_queue_head(9), skb_queue_tail(9), skb_unlink(9), skb_append(9), skb_split(9), skb_shift(9), skb_prepare_seq_read(9), skb_seq_read(9), skb_abort_seq_read(9), skb_copy_seq_read(9), skb_find_text(9), skb_pull_rcsum(9), skb_segment(9), skb_to_sgvec(9), skb_cow_data(9), skb_clone_sk(9), skb_partial_csum_set(9), skb_checksum_setup(9), skb_checksum_maybe_trim(9), skb_checksum_trimmed(9), skb_try_coalesce(9), skb_scrub_packet(9), skb_eth_pop(9), skb_eth_push(9), skb_mpls_push(9), skb_mpls_pop(9), skb_mpls_update_lse(9), skb_mpls_dec_ttl(9), alloc_skb_with_frags(9), skb_condense(9), __skb_ext_alloc(9), __skb_ext_set(9), skb_ext_add(9), skb_attempt_defer_free(9), skb_splice_from_iter(9)

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Signed, sealed, delivered from ./net/core, October 2026 — page __pskb_pull_tail(9) out 💅✨🎀