calipso_optptr(9)

✨ NAME ✨

calipso_optptr — find the CALIPSO option in the packet 🌸

okay so this is a section 9 kernel API page (yes the manual name is Kernel API Manual, iykyk 🧚) and it's literally just one little lookup helper. let's get into it 💅

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🦋 SYNOPSIS 🦋

unsigned char * calipso_optptr (const struct sk_buff *skb );

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🎀 ARGUMENTS 🎀

• skb — the packet 💌 that's it, that's the whole argument list, bestie

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💖 DESCRIPTION 💖

so here's the vibe: calipso_optptr parses the packet's IP header, looking for a CALIPSO option 👑

on success it returns a pointer to the start of the CALIPSO option. if one is not found, you get NULL — no option, no pointer, that's the deal 🙈

periodt. that's the entire behaviour, and honestly? iconic for being so simple 🌟

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🌈 SEE ALSO 🌈

the kernel file lives right here, go read it bestie:

./net/netlabel/netlabel_calipso.c

and the whole calipso/netlabel family, all of them, in the order they came in — not me listing all 25 of these 😭🫶

• netlbl_calipso_ops_register(9)
• netlbl_calipso_add_pass(9)
• netlbl_calipso_add(9)
• netlbl_calipso_list(9)
• netlbl_calipso_listall_cb(9)
• netlbl_calipso_listall(9)
• netlbl_calipso_remove_cb(9)
• netlbl_calipso_remove(9)
• netlbl_calipso_genl_init(9)
• calipso_doi_add(9)
• calipso_doi_free(9)
• calipso_doi_remove(9)
• calipso_doi_getdef(9)
• calipso_doi_putdef(9)
• calipso_doi_walk(9)
• calipso_sock_getattr(9)
• calipso_sock_setattr(9)
• calipso_sock_delattr(9)
• calipso_req_setattr(9)
• calipso_req_delattr(9)
• calipso_getattr(9)
• calipso_skbuff_setattr(9)
• calipso_skbuff_delattr(9)
• calipso_cache_invalidate(9)
• calipso_cache_add(9)

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and that's the page!! 🦋 mwah, go find those CALIPSO options bestie 💅

source/version is ./net/netlabel, dated October 2026 — so this manual page is basically a time capsule from the future, slay ⭐