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libbpf-cargo helps you develop and build eBPF (BPF) programs with standard rust tooling.

libbpf-cargo supports two interfaces:

The build script interface is recommended over the cargo subcommand interface because:

  • once set up, you cannot forget to update the generated skeletons if your source changes
  • build scripts are standard practice for projects that include codegen
  • newcomers to your project can cargo build and it will “just work”

The following sections in this document describe the cargo-libbpf plugin. See the API reference for documentation on the build script interface.


cargo-libbpf consumes the following Cargo.toml configuration options:

prog_dir = "src/other_bpf_dir"  # default: <manifest_directory>/src/bpf
target_dir = "other_target_dir" # default: <target_dir>/bpf
  • prog_dir: path relative to package Cargo.toml to search for bpf progs
  • target_dir: path relative to workspace target directory to place compiled bpf progs



cargo libbpf build compiles <NAME>.bpf.c C files into corresponding <NAME>.bpf.o ELF object files. Each object file may contain one or more BPF programs, maps, and associated metadata. The object file may then be handed over to libbpf-rs for loading and interaction.

cargo-libbpf-build enforces a few conventions:

  • source file names must be in the <NAME>.bpf.c format
  • object file names will be generated in <NAME>.bpf.o format
  • there may not be any two identical <NAME>.bpf.c file names in any two projects in a cargo workspace


cargo libbpf gen generates a skeleton module for each BPF object file in the project. Each <NAME>.bpf.o object file will have its own module. One mod.rs file is also generated. All output files are placed into package.metadata.libbpf.prog_dir.

Be careful to run cargo-libbpf-build before running cargo-libbpf-gen. cargo-libbpf-gen reads object files from package.metadata.libbpf.target_dir.


cargo libbpf make sequentially runs cargo-libbpf-build, cargo-libbpf-gen, and cargo build. This is a convenience command so you don’t forget any steps. Alternatively, you could write a Makefile for your project.


SkeletonBuilder builds and generates a single skeleton.


Canonical error type for this crate.

Type Definitions