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   bpf-helpers    ( 7 )

список вспомогательных функций eBPF (list of eBPF helper functions)

Имя (Name)

BPF-HELPERS - list of eBPF helper functions


Описание (Description)

The extended Berkeley Packet Filter (eBPF) subsystem consists in programs written in a pseudo-assembly language, then attached to one of the several kernel hooks and run in reaction of specific events. This framework differs from the older, "classic" BPF (or "cBPF") in several aspects, one of them being the ability to call special functions (or "helpers") from within a program. These functions are restricted to a white-list of helpers defined in the kernel.

These helpers are used by eBPF programs to interact with the system, or with the context in which they work. For instance, they can be used to print debugging messages, to get the time since the system was booted, to interact with eBPF maps, or to manipulate network packets. Since there are several eBPF program types, and that they do not run in the same context, each program type can only call a subset of those helpers.

Due to eBPF conventions, a helper can not have more than five arguments.

Internally, eBPF programs call directly into the compiled helper functions without requiring any foreign-function interface. As a result, calling helpers introduces no overhead, thus offering excellent performance.

This document is an attempt to list and document the helpers available to eBPF developers. They are sorted by chronological order (the oldest helpers in the kernel at the top).