calipso_cache_check(9)

🦋 calipso_cache_check — bestie edition 💅

okay so this is a page from the Kernel API Manual, and today's main character is calipso_cache_check ✨

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✨ NAME ✨

calipso_cache_check — check the CALIPSO cache for a label mapping 🔍

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🌸 SYNOPSIS 🌸

int calipso_cache_check (const unsigned char *key , u32 key_len ,
                         struct netlbl_lsm_secattr *secattr );

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🎀 ARGUMENTS 🎀

• key — the buffer you wanna check, that's the vibe
• key_len — how long that buffer is, in bytes, no cap
• secattr — the security attribute struct you're gonna use 🫶

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💖 DESCRIPTION 💖

So basically this function peeks into the cache to see if a label mapping already exists for the key you handed it. If there's a match, the cache gets adjusted and the secattr struct gets populated with the correct LSM security attributes. Literally doing the most for you 💅

Now — here's the fun part — if the entry is not already the first one in the cache bucket, the cache gets adjusted in this exact way:

1. The cache entry's activity counter gets incremented ⬆️
2. The previous (higher ranking) entry's activity counter gets decremented ⬇️
3. If the difference between the two activity counters is "geater" than CALIPSO_CACHE_REORDERLIMIT, the two entries get swapped 🔄

the original doc really said "geater" and honestly? we respect the typo. it means greater, bestie 😭

Returns zero on success, -ENOENT for a cache miss, and other negative values on error. periodt. ✨

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🔥 SEE ALSO 🔥

The kernel file lives at ./net/ipv6/calipso.c, and it's giving family reunion, because here's the whole crew:

• calipso_cache_entry_free(9)
• calipso_map_cache_hash(9)
• calipso_cache_init(9)
• calipso_cache_invalidate(9)
• calipso_cache_add(9)
• calipso_doi_search(9)
• calipso_doi_add(9)
• calipso_doi_free(9)
• calipso_doi_free_rcu(9)
• calipso_doi_remove(9)
• calipso_doi_getdef(9)
• calipso_doi_putdef(9)
• calipso_doi_walk(9)
• calipso_validate(9)
• calipso_map_cat_hton(9)
• calipso_map_cat_ntoh(9)
• calipso_pad_write(9)
• calipso_genopt(9)
• calipso_opt_update(9)
• calipso_tlv_len(9)
• calipso_opt_find(9)
• calipso_opt_insert(9)
• calipso_opt_del(9)
• calipso_opt_getattr(9)
• calipso_sock_getattr(9)
• calipso_sock_setattr(9)
• calipso_sock_delattr(9)
• calipso_req_setattr(9)
• calipso_req_delattr(9)
• calipso_skbuff_optptr(9)
• calipso_skbuff_setattr(9)
• calipso_skbuff_delattr(9)
• calipso_init(9)

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aaaand that's the page!! 🧚 mwah 💋

sign-off besties: this one's from the kernel file under ./net/ipv6, dated October 2026, and it's filed as calipso_cache_check(9) — go read the whole collection, iykyk 💜🌈