BPFJIT(4)

🎀 NAME 🎀

bpfjit — Just-In-Time compiler for Berkeley Packet Filter. Yes bestie, this is the BPFJIT(4) manual page, and we are gonna get through it together, no cap 💖

🛠️ SYNOPSIS 🛠️

options BPFJIT
options SLJIT

💅 DESCRIPTION 💅

Okay so the bpfjit kernel interface adds Just-In-Time compilation for filter programs that get sent to a bpf(4) device. Instead of being interpreted for every packet, these filter programs are compiled into native code, and that code is being executed for every packet. It’s giving “main character energy” for your packet path ✨

The implementation of bpfjit is based on the Stack-Less Just-In-Time library, or sljit for short. The library supports multiple platforms, including:

• AMD-x86 64
• ARM 32 (ARM-v5, ARM-v7 and Thumb2 instruction sets)
• Intel-x86 32
• MIPS 32 (III, R1)
• MIPS 64 (III, R1)
• PowerPC 32
• PowerPC 64
• SPARC 32

bpfjit supports all architectures listed above. Iconic behavior, honestly 👑

bpfjit is also available as a module in modular kernels. So modular-kernel besties are included too 🫶

🎛️ SYSCTLS 🎛️

The following sysctl is available when bpfjit is enabled:

• net.bpf.jit — Toggle Just-In-Time compilation of new filter programs. Changing a value of this sysctl doesn't affect existing filter programs.

Heads up, bestie: changing this sysctl only touches new filter programs — the existing ones stay exactly as they are, periodt 💅

👀 SEE ALSO 👀

• bpf(4)
• modload(8)
• sljit library: https://zherczeg.github.io/sljit/

🌸 HISTORY 🌸

The bpfjit interface first appeared in NetBSD 7.0. A whole little historical moment, fr fr 🦋

🫶 AUTHORS 🫶

The bpfjit code was written by Alexander Nasonov <alnsn@NetBSD.org>.

The sljit library was written by Zoltan Herczeg <hzmester@freemail.hu>.

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Cute lil sign-off time: this page is from the Debian manual set, dated July 24, 2014, and it’s the BPFJIT(4) page — slay and goodbye, bestie 💖🎀✨