pipapo_drop(9)

💅 pipapo_drop(9) — the Kernel API Manual page, but make it make sense

okay so bestie, welcome to the Kernel API Manual, section 9 (that's the kernel-functions girlies 🌸). Today's main character is pipapo_drop — she deletes stuff, and honestly? she ate.

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📛 NAME

pipapo_drop — delete an entry from the lookup and mapping tables, given a rule map. that's it, that's the whole job 🫶

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✨ SYNOPSIS

void pipapo_drop (struct nft_pipapo_match *m , union
nft_pipapo_map_bucket rulemap[] );

literally just those two things, no cap ✨

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🎀 ARGUMENTS

• m — the matching data. yep. that's the vibe. 💖
• rulemap — the table of rule maps: arrays of the first rule, plus the amount of rules in the next field that a given entry maps to, for each field. so it's like, a little itinerary of where everything lives 🗺️

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🦋 DESCRIPTION

okay so picture this: for each rule in the lookup table buckets that map to this set of rules, we drop all the bits that are set in the lookup table mapping. slay, but also slightly unhinged energy 🔥

in pictures — and yes, we're doing diagrams, stay with me — imagine we want to drop rules 0 and 1 from this lookup table:

       bucket group  0   1   2   3   4   5   6   7   8   9  10  11  12  13  14
       15 0    0                                              1,2 1   1,2
       0 2    0                                      1,2 3    0
       1,2 4  0,1,2 5    0   1   2 6  0,1,2 1   1   1   1   1   1   1   1   1
       1   1   1   1   1   1 7   1,2 1,2  1   1   1  0,1  1   1   1   1   1   1
       1   1   1   1

so then rule 2 becomes rule 0, and the glow-up result is this:

       bucket group  0   1   2   3   4   5   6   7   8   9  10  11  12  13  14
       15 0                                                    0 1    0 2
       0 3                                    0 4    0 5            0 6    0 7
       0   0

like... the way the numbers just renumber themselves? iconic. 👑

and once that's done, you call unmap to drop all the corresponding rule references from the mapping tables. it's giving cleanup era, it's giving closure. periodt. 💅

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👀 SEE ALSO

the whole friend group, fr fr — go say hi:

• Kernel file ./net/netfilter/nft_set_pipapo.c Theory of Operation(9)
• pipapo_refill(9)
• pipapo_get_slow(9)
• pipapo_get(9)
• nft_pipapo_lookup(9)
• nft_pipapo_get(9)
• pipapo_realloc_mt(9)
• lt_calculate_size(9)
• pipapo_resize(9)
• pipapo_bucket_set(9)
• pipapo_lt_4b_to_8b(9)
• pipapo_lt_8b_to_4b(9)
• pipapo_lt_bits_adjust(9)
• pipapo_insert(9)
• pipapo_step_diff(9)
• pipapo_step_after_end(9)
• pipapo_base_sum(9)
• pipapo_expand(9)
• pipapo_map(9)
• pipapo_free_scratch(9)
• pipapo_realloc_scratch(9)
• pipapo_maybe_clone(9)
• nft_pipapo_insert(9)
• pipapo_clone(9)
• pipapo_rules_same_key(9)
• pipapo_unmap(9)
• pipapo_gc_scan(9)
• pipapo_gc_queue(9)
• pipapo_free_fields(9)
• pipapo_reclaim_match(9)
• nft_pipapo_commit(9)
• nft_pipapo_activate(9)
• nft_pipapo_deactivate(9)
• nft_pipapo_flush(9)
• pipapo_get_boundaries(9)
• pipapo_match_field(9)
• nft_pipapo_remove(9)
• nft_pipapo_do_walk(9)
• nft_pipapo_walk(9)
• nft_pipapo_privsize(9)
• nft_pipapo_estimate(9)
• nft_pipapo_init(9)
• nft_set_pipapo_match_destroy(9)
• nft_pipapo_destroy(9)
• nft_pipapo_gc_init(9)

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and that's the whole page, bestie!! this lil masterpiece lives in the <lavender>./net/netfilter</lavender> corner of the kernel, and the source/version + date stamp is <pink>October 2026</pink> 🎀 go forth, drop those entries, and remember: the bits were set, and now they're not. no cap, iykyk 💖✨