xt_copy_counters(9)

🎀 xt_copy_counters(9) 🎀

Kernel API Manual — bestie, we're copying counters and metadata from a sockptr_t, and yes, it's giving kernel-core 💅

✨ NAME ✨

xt_copy_counters — copy counters and metadata from a sockptr_t 💖

🦋 SYNOPSIS 🦋

void * xt_copy_counters (sockptr_t arg , unsigned int len , struct
       xt_counters_info *info );

🌈 ARGUMENTS 🌈

• arg — the src sockptr 🫶
• len — the alleged size of userspace memory 😭 (yes, “alleged” is doing a lot of work here)
• info — where to store the xt_counters_info metadata 👑

💜 DESCRIPTION 💜

Okay so first things first: it copies counter meta data from user and stores it in info 📥.

Then it vmallocs memory to hold the counters 🧠, copies the counter data from user into that new memory, and returns a pointer to it 🔥.

If called from a compat syscall, info gets converted automatically to the 64bit representation ✨.

The metadata associated with the counters is stored in info 🎀.

👑 RETURN 👑

It returns a pointer that the caller has to test via IS_ERR 👀. If IS_ERR is false, the caller has to vfree the pointer — periodt 💀🫶

🧚 SEE ALSO 🧚

Kernel file: ./net/netfilter/x_tables.c 📁

• xt_check_proc_name(9)
• xt_check_entry_offsets(9)
• xt_alloc_entry_offsets(9)
• xt_find_jump_offset(9)
• xt_unregister_table_pre_exit(9)
• xt_unregister_table_exit(9)
• xt_hook_ops_alloc(9)
• xt_percpu_counter_alloc(9)

That's the whole vibe check, bestie 🫶 — source/version: ./net/netfilter, dated October 2026 💖✨