iptfs_input_save_runt(9)

💾 iptfs_input_save_runt(9) 💾

okay so real talk, this one is from the Kernel API Manual — section 9, kernel-space bestie territory 🧚. It's a teeny tiny little function and honestly it's giving "small but mighty", so let's get into it.

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✨ NAME ✨

iptfs_input_save_runt — it saves data in the xtfs runt space 🎀 (yes, "runt", that's the actual name, we don't make the rules, we just document them).

🌸 SYNOPSIS 🌸

void iptfs_input_save_runt (struct xfrm_iptfs_data *xtfs , u64 seq , u8
*buf , int len );

no return value, it's a void, she simply does the thing and leaves 💅

💖 ARGUMENTS 💖

• xtfs — the xtfs state, like, the whole vibe/context object
• seq — the current sequence 🦋
• buf — packet data, the actual bytes
• len — length of packet data

🔥 DESCRIPTION 🔥

So basically: take the small-ish start of a fragmented packet — that's your len bytes sitting in buf — and save it in the xtfs data runt space. That's it. That's the whole job. Iconic, lowkey, minimal. ✨

ngl the word "runt" is doing a lot of heavy lifting here but it's literally the name of the space, so we're keeping it 🍓

👑 SEE ALSO 👑

Kernel file ./net/xfrm/xfrm_iptfs.c, plus the whole friend group:

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_add_frags(9), iptfs_pskb_extract_seq(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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okay that's the whole page, no notes 💜

sign-off time: this one lives under ./net/xfrm and the date on it is October 2026 — so yeah, she's from the future, main character energy fr fr 🌈⭐ mwah 💅