iptfs_pskb_add_frags(9)

💅 iptfs_pskb_add_frags — from the Kernel API Manual, bestie 🎀

okay so this is iptfs_pskb_add_frags(9) and no cap, it's literally the glow-up arc for sk_buffs: it takes a template and a pile of fragments and builds you a brand new sk_buff. iconic behavior honestly ✨

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🌸 NAME 🌸

iptfs_pskb_add_frags — create and add frags into a new sk_buff. that's it, that's the whole vibe 🦋

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⭐ SYNOPSIS ⭐

struct sk_buff * iptfs_pskb_add_frags (struct sk_buff *tpl , struct
       iptfs_skb_frag_walk *walk , u32 off , u32 len , struct skb_seq_state *st
       , u32 copy_len );

yes it's a long signature, don't panic, we're gonna walk through every single arg together 🫶

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🎀 ARGUMENTS 🎀

• tpl — the template, aka the blueprint. the new skb gets created from this one. main character energy from the jump 👑
• walk — the source for the fragments you're adding. this is where the frags live, we're just borrowing them 💜
• off — the offset into walk where you start pulling frags from. also gets used with st and copy_len, so it's a busy girl. multi-tasking queen 💅
• len — the length of data to add, covering the frags from walk into the skb. this must be <= skblen — fr fr, don't test it 🫣
• st — the sequence state that gets copied into the new head skb 🌈
• copy_len — copy copy_len bytes from st at offset off into the new skb's linear space. head space gets the love first 💖

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✨ DESCRIPTION ✨

so here's the whole storyline, bestie:

it creates a brand new sk_buff called skb using the template tpl 🧚

then it copies copy_len bytes from st into the new skb's linear space (the head, basically — the cozy part) 🍓

and then for the remaining len of data — like, literally len - copy_len bytes — it adds shared fragments from the frag walk 🔥

so it's giving: little bit of linear, whole lot of shared frags, one gorgeous new skb at the end. ate and left no crumbs 💀

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👑 RETURN 👑

the newly allocated sk_buff skb — yay 🎉

or NULL if an error occurs 😭 (yes it can fail, and when it does, NULL is all you get, so check it, iykyk)

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🦋 SEE ALSO 🦋

all the siblings and cousins, alphabetically unbothered:

• Kernel file ./net/xfrm/xfrm_iptfs.c
• IPTFS_DEFAULT_DROP_TIME_USECS(9)
• IPTFS_DEFAULT_REORDER_WINDOW(9)
• IPTFS_DEFAULT_INIT_DELAY_USECS(9)
• IPTFS_DEFAULT_MAX_QUEUE_SIZE(9)
• struct xfrm_iptfs_config(9)
• struct xfrm_iptfs_data(9)
• iptfs_alloc_skb(9)
• iptfs_skb_head_to_frag(9)
• struct iptfs_skb_frag_walk(9)
• iptfs_skb_prepare_frag_walk(9)
• iptfs_skb_can_add_frags(9)
• iptfs_skb_add_frags(9)
• iptfs_pskb_extract_seq(9)
• iptfs_input_save_runt(9)
• __iptfs_iphlen(9)
• __iptfs_iplen(9)
• iptfs_complete_inner_skb(9)
• iptfs_reassem_abort(9)
• iptfs_reassem_done(9)
• iptfs_reassem_cont(9)
• iptfs_input_ordered(9)
• iptfs_drop_timer(9)
• iptfs_input(9)
• iptfs_enqueue(9)
• iptfs_copy_create_frag(9)
• iptfs_copy_create_frags(9)
• iptfs_first_skb(9)
• iptfs_encap_add_ipv4(9)
• iptfs_encap_add_ipv6(9)
• iptfs_prepare_output(9)
• __iptfs_get_inner_mtu(9)
• iptfs_get_inner_mtu(9)
• iptfs_user_init(9)

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ngl the frag walk stuff is a whole friend group — go read iptfs_skb_prepare_frag_walk(9) and iptfs_skb_can_add_frags(9) before you start adding frags, bestie, save yourself the pain 🙈

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and that's the page!! 🌸 mwah 💋

this little masterpiece is filed under ./net/xfrm, dated October 2026, and it's page iptfs_pskb_add_frags(9) of the Kernel API Manual — go off, kernel docs, you absolute icons 🌈⭐💜