iptfs_first_skb(9)

✨ NAME ✨

okay so this is iptfs_first_skb(9), straight outta the Kernel API Manual, and its whole job is to handle the first dequeued inner packet for output. 💅

🛰️ SYNOPSIS 🛰️

int iptfs_first_skb (struct sk_buff **skbp , struct xfrm_iptfs_data
*xtfs , u32 mtu );

🎀 ARGUMENTS 🎀

• skbp — the source packet skb (IN), plus the skb holding the last fragment in the fragment stream (OUT). Same argument, both directions, iykyk. 💫
• xtfs — IPTFS SA state. That’s the state, bestie. 🌸
• mtu — the max IPTFS fragment size. Literally the max. 💀

🧚 DESCRIPTION 🧚

This function is responsible for fragmenting a larger inner packet into a sequence of IPTFS payload packets. Slay. ✨

The last fragment is returned rather than being sent, so the caller can append more inner packets (aggregation) if there is room. That’s the whole vibe: hand back the final fragment so the caller can keep stacking if there’s space. 🫶

💖 RETURN 💖

0 on success or a negative error code on failure. Periodt. 💅

🌈 SEE ALSO 🌈

Grab a snack, because SEE ALSO is giving a whole ensemble cast. First, the kernel file:

• 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_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_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)

💖 cute sign-off: this page comes from source/version ./net/xfrm, dated October 2026, and yes, it’s still iptfs_first_skb(9). Mwah! 💖