cipso_v4_map_cat_rbm_valid(9)

📦 version 7.3.1, in nixpkgs unstable

💅 cipso_v4_map_cat_rbm_valid — a Kernel API Manual moment ✨

okay so bestie, we're deep in the kernel today and the manual we're vibing with is the Kernel API Manual entry for cipso_v4_map_cat_rbm_valid(9). yes it's a mouthful, no you don't have to say it out loud 🫶

✨ NAME ✨

cipso_v4_map_cat_rbm_valid — literally just checks to see if the category bitmap is valid. that's it. that's the whole gig 💅

🌸 SYNOPSIS 🌸

int cipso_v4_map_cat_rbm_valid (const struct cipso_v4_doi *doi_def ,
const unsigned char *bitmap , u32 bitmap_len );

like, three little args, one int back. iconic behavior honestly 👑

🎀 ARGUMENTS 🎀

  • doi_def — the DOI definition. your whole reference point, main character energy fr.
  • bitmap — the category bitmap. the thing we're checking, no cap.
  • bitmap_len — how long that bitmap is, measured in bytes. don't forget the units bestie, bytes not bits 😭

🦋 DESCRIPTION 🦋

okay so what this function actually does: it takes the given category bitmap and checks it against the given DOI definition. that's the vibe check 🌈

then it reports back:

  • a negative value if any of the categories in the bitmap don't have a valid mapping — like, even one lil invalid category and it's giving 🚩
  • a zero value if all of the categories are valid — slay, we love a clean pass ✨
ngl the whole point is that "any" — one bad category in the bitmap and you get the negative. it's not a "mostly fine" situation, it's an all-or-nothing situation 💀

👑 SEE ALSO 👑

this is the part where the kernel introduces you to its entire friend group. so many icons in one file, and I mean the source file ./net/ipv4/cipso_ipv4.c, of course 💖

okay that's the whole page bestie, you ate that 🍓 this one came from ./net/ipv4 and the date on it is October 2026 — so go forth, validate those bitmaps, and remember: cipso_v4_map_cat_rbm_valid(9), iykyk 💜🧚

📦 where this page comes from