cipso_v4_cache_add(9)

📦 version 7.3.1, in nixpkgs unstable

💖 NAME 💖

cipso_v4_cache_add — bestie, this is the function that adds an entry to the CIPSO cache ✨ (yes, that's literally its whole job and it does it gorgeously)

So this lil guy lives in the kernel's Kernel API Manual section 9, and it's lowkey a whole vibe — it takes a CIPSO label and slots it into the label mapping cache. Let's get into it 🫶

⭐ SYNOPSIS ⭐

int cipso_v4_cache_add (const unsigned char *cipso_ptr , const struct
       netlbl_lsm_secattr *secattr );

Two args, one int coming back at you. That's the whole signature, no cap 💅

🎀 ARGUMENTS 🎀

  • cipso_ptr — pointer to the CIPSO IP option 🦋 like, this is the actual CIPSO option data you're feeding in
  • secattr — the packet's security attributes 🌸 the secattr half of the deal

🔥 DESCRIPTION 🔥

Okay so here's the tea ☕ — cipso_v4_cache_add adds a new entry into the CIPSO label mapping cache. That's it, that's the function.

The way it does it is lowkey iconic: the new entry goes to the head of the cache bucket's list 👑 so it's giving main character energy, front of the line, no waiting.

And if the cache bucket is out of room? 🫣 Then it removes the last entry in the list first before squeezing the new one in. Very "you can't sit with us" of it honestly. Bye bestie, you're evicted 💀

⚠️ IMPORTANT NOTE, FR FR: there is currently no checking for duplicate keys. Like, none. Zero. The function will not notice, will not warn you, will not throw a vibe check at your duplicate — it will simply add it. So don't come for it later, okay? 🙈

Returns zero on success ✨, and negative values on failure 😭. That's the whole return contract, memorise it, it's on the test.

🌈 SEE ALSO 🌈

Kernel file ./net/ipv4/cipso_ipv4.c — go read the source, it's right there:

💜 and that's the whole page bestie 💜 this one came out of the ./net/ipv4 source tree, October 2026 edition, Kernel API Manual energy all the way through 🧚‍♀️ mwah, go add some cache entries, ily 🍓

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