STRUCT XT_TGCHK_PARAM(9)

💖 struct xt_tgchk_param(9) 💖

okay bestie, so this is a page straight out of the Kernel API Manual and it's literally all about struct xt_tgchk_param — the little bundle of parameters you hand over to target extensions' checkentry functions ✨. yes, that's the whole vibe. it's giving "paperwork for your netfilter target" and honestly? iconic.

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🎀 NAME 🎀

struct xt_tgchk_param — the parameters for target extensions' checkentry functions, no cap 🫶

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🌸 SYNOPSIS 🌸

struct xt_tgchk_param {
    struct net *net;
    const char *table;
    const void *entryinfo;
    const struct xt_target *target;
    void *targinfo;
    unsigned int hook_mask;
    u_int8_t family;
    bool nft_compat;
 };

like, that's the struct. every field matters, don't skip a single one 💅

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🦋 Members 🦋

okay so let's go field by field, main character energy only:

• net — the network namespace through which the check was invoked 🌐 like, which netns are we even in rn
• table — the table the rule is tried to be inserted into 📋 the destination, basically
• entryinfo — the family-specific rule data (that's struct ipt_entry, ip6t_entry, arpt_entry, ebt_entry) 👑 so it depends on the family, iykyk
• target — the target extension itself 🎯 the star of the show
• targinfo — per-target data 💫 each target gets its own lil payload
• hook_mask — via which hooks the new rule is reachable 🪝 hook reachability, fr fr
• family — the actual NFPROTO_* through which the function is invoked 🔥 and super helpful when match->family == NFPROTO_UNSPEC, because then you'd be lost otherwise ngl
• nft_compat — true if this is running from the nft compat layer ✅ that's it, that's the flag

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💜 SEE ALSO 💜

go touch some grass in the kernel source, bestie 🌈:

• Kernel file ./include/linux/netfilter/x_tables.h struct xt_action_param(9)
• struct xt_mtchk_param(9)
• struct xt_mtdtor_param(9)
• var xt_recseq(9)
• xt_write_recseq_begin(9)
• xt_write_recseq_end(9)

lowkey important: those are the exact names, don't go renaming them in your head, they will not find you 😭

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aaaand that's the page!! 🌟 this one's brought to you from ./include/linux/netfilter, dated October 2026 — so like, mark your calendars, this manual page is a whole era 🎀💖 slay, now go write your checkentry function. periodt. 💅✨