STRUCT NFT_SET_EXT(9)

💖 struct nft_set_ext(9) 💖

Bestie, welcome to the Kernel API Manual entry for struct nft_set_ext — the set extensions struct, and yes, it's giving main-character kernel energy. ✨

🌸 NAME 🌸

struct nft_set_ext — set extensions. That's literally the name, and it ate. 💅

🦋 SYNOPSIS 🦋

       struct nft_set_ext {
           u8 genmask;
           u8 offset[NFT_SET_EXT_NUM];
           char data[];
        };

🎀 Members 🎀

• genmask — the generation mask, but also flags (see NFT_SET_ELEM_DEAD_BIT). Yes, it’s doing double duty, slay. 🎀
• offset — offsets of individual extension types. Keeping track of where everyone lives, lowkey iconic. 💅
• data — beginning of extension data. The actual data starts here, no cap. 🦋

🌈 Description 🌈

Okay so here’s the alignment tea: this structure must be aligned to word size, otherwise atomic bitops on the genmask field can cause alignment failure on some archs. Not me forgetting the alignment warning, bestie — that’s a real caveat. 😭 Keep it aligned, fr fr. 💜

👑 SEE ALSO 👑

Kernel file: ./include/net/netfilter/nf_tables.h — the kernel fam is all here:

• struct nft_verdict(9)
• struct nft_regs(9)
• struct nft_ctx(9)
• struct nft_userdata(9)
• struct nft_set_elem(9)
• enum nft_iter_type(9)
• struct nft_set_desc(9)
• enum nft_set_class(9)
• struct nft_set_estimate(9)
• struct nft_expr(9)
• struct nft_set_ops(9)
• struct nft_set_type(9)
• struct nft_set(9)
• struct nft_set_binding(9)
• enum nft_set_extensions(9)
• struct nft_set_ext_type(9)
• struct nft_set_ext_tmpl(9)
• struct nft_expr_type(9)
• struct nft_expr_ops(9)
• struct nft_rule(9)
• struct nft_chain_validate_state(9)
• struct nft_chain(9)
• struct nft_chain_type(9)
• struct nft_base_chain(9)
• struct nft_table(9)
• struct nft_object_hash_key(9)
• struct nft_object(9)
• struct nft_object_type(9)
• struct nft_object_ops(9)
• struct nft_flowtable(9)
• struct nft_traceinfo(9)
• struct nft_trans(9)
• struct nft_trans_hook(9)
• struct nft_trans_binding(9)

That’s the whole squad. 🫶

Catch you in ./include/net/netfilter — this page is dated October 2026, and it’s the struct nft_set_ext(9) manual page from the Kernel API Manual. Bye bestie, stay aligned 💜🦋✨