2042df2fed
Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit: c6bde958a62b8ca5ee8d2c1fe429aec4ad54efad
Checkpoint bpf-next commit: 5c667dca71095abec90420eb09503f35f66c9585
Baseline bpf commit: d3bec0138bfbe58606fc1d6f57a4cdc1a20218db
Checkpoint bpf commit: 12c8a8ca117f3d734babc3fba131fdaa329d2163
Alan Maguire (1):
libbpf: bpf__find_by_name[_kind] should use btf__get_nr_types()
Andrei Matei (1):
libbpf: Fail early when loading programs with unspecified type
Andrii Nakryiko (11):
bpf: Assign ID to vmlinux BTF and return extra info for BTF in
GET_OBJ_INFO
libbpf: Don't attempt to load unused subprog as an entry-point BPF
program
libbpf: Add base BTF accessor
libbpf: Add internal helper to load BTF data by FD
libbpf: Refactor CO-RE relocs to not assume a single BTF object
libbpf: Add kernel module BTF support for CO-RE relocations
bpf: Allow to specify kernel module BTFs when attaching BPF programs
libbpf: Factor out low-level BPF program loading helper
libbpf: Support attachment of BPF tracing programs to kernel modules
libbpf: Use memcpy instead of strncpy to please GCC
libbpf: Fix ring_buffer__poll() to return number of consumed samples
Dmitrii Banshchikov (1):
bpf: Add bpf_ktime_get_coarse_ns helper
KP Singh (5):
bpf: Implement task local storage
libbpf: Add support for task local storage
bpf: Implement get_current_task_btf and RET_PTR_TO_BTF_ID
bpf: Add bpf_bprm_opts_set helper
bpf: Add a BPF helper for getting the IMA hash of an inode
Li RongQing (1):
libbpf: Add support for canceling cached_cons advance
Magnus Karlsson (1):
libbpf: Replace size_t with __u32 in xsk interfaces
Mariusz Dudek (1):
libbpf: Separate XDP program load with xsk socket creation
Stanislav Fomichev (1):
libbpf: Cap retries in sys_bpf_prog_load
Thomas Karlsson (1):
macvlan: Support for high multicast packet rate
Toke Høiland-Jørgensen (1):
libbpf: Sanitise map names before pinning
include/uapi/linux/bpf.h | 96 +++++-
include/uapi/linux/if_link.h | 2 +
src/bpf.c | 104 +++++--
src/btf.c | 74 +++--
src/btf.h | 1 +
src/libbpf.c | 550 +++++++++++++++++++++++++++--------
src/libbpf.map | 3 +
src/libbpf_internal.h | 31 ++
src/libbpf_probes.c | 1 +
src/ringbuf.c | 2 +-
src/xsk.c | 92 +++++-
src/xsk.h | 22 +-
12 files changed, 771 insertions(+), 207 deletions(-)
--
2.24.1
BPF/libbpf usage and questions
Please check out libbpf-bootstrap and the companion blog post for the examples of building BPF applications with libbpf. libbpf-tools are also a good source of the real-world libbpf-based tracing tools.
All general BPF questions, including kernel functionality, libbpf APIs and their application, should be sent to bpf@vger.kernel.org mailing list. You can subscribe to it here and search its archive here. Please search the archive before asking new questions. It very well might be that this was already addressed or answered before.
bpf@vger.kernel.org is monitored by many more people and they will happily try to help you with whatever issue you have. This repository's PRs and issues should be opened only for dealing with issues pertaining to specific way this libbpf mirror repo is set up and organized.
Build
libelf is an internal dependency of libbpf and thus it is required to link
against and must be installed on the system for applications to work.
pkg-config is used by default to find libelf, and the program called can be
overridden with PKG_CONFIG.
If using pkg-config at build time is not desired, it can be disabled by
setting NO_PKG_CONFIG=1 when calling make.
To build both static libbpf.a and shared libbpf.so:
$ cd src
$ make
To build only static libbpf.a library in directory build/ and install them together with libbpf headers in a staging directory root/:
$ cd src
$ mkdir build root
$ BUILD_STATIC_ONLY=y OBJDIR=build DESTDIR=root make install
To build both static libbpf.a and shared libbpf.so against a custom libelf dependency installed in /build/root/ and install them together with libbpf headers in a build directory /build/root/:
$ cd src
$ PKG_CONFIG_PATH=/build/root/lib64/pkgconfig DESTDIR=/build/root make install
Distributions
Distributions packaging libbpf from this mirror:
Benefits of packaging from the mirror over packaging from kernel sources:
- Consistent versioning across distributions.
- No ties to any specific kernel, transparent handling of older kernels. Libbpf is designed to be kernel-agnostic and work across multitude of kernel versions. It has built-in mechanisms to gracefully handle older kernels, that are missing some of the features, by working around or gracefully degrading functionality. Thus libbpf is not tied to a specific kernel version and can/should be packaged and versioned independently.
- Continuous integration testing via TravisCI.
- Static code analysis via LGTM and Coverity.
Package dependencies of libbpf, package names may vary across distros:
- zlib
- libelf
BPF CO-RE (Compile Once – Run Everywhere)
Libbpf supports building BPF CO-RE-enabled applications, which, in contrast to BCC, do not require Clang/LLVM runtime being deployed to target servers and doesn't rely on kernel-devel headers being available.
It does rely on kernel to be built with BTF type information, though. Some major Linux distributions come with kernel BTF already built in:
- Fedora 31+
- RHEL 8.2+
- OpenSUSE Tumbleweed (in the next release, as of 2020-06-04)
- Arch Linux (from kernel 5.7.1.arch1-1)
- Ubuntu 20.10
If your kernel doesn't come with BTF built-in, you'll need to build custom kernel. You'll need:
pahole1.16+ tool (part ofdwarvespackage), which performs DWARF to BTF conversion;- kernel built with
CONFIG_DEBUG_INFO_BTF=yoption; - you can check if your kernel has BTF built-in by looking for
/sys/kernel/btf/vmlinuxfile:
$ ls -la /sys/kernel/btf/vmlinux
-r--r--r--. 1 root root 3541561 Jun 2 18:16 /sys/kernel/btf/vmlinux
To develop and build BPF programs, you'll need Clang/LLVM 10+. The following distributions have Clang/LLVM 10+ packaged by default:
- Fedora 32+
- Ubuntu 20.04+
- Arch Linux
- Ubuntu 20.10 (LLVM 11)
Otherwise, please make sure to update it on your system.
The following resources are useful to understand what BPF CO-RE is and how to use it:
- BPF Portability and CO-RE
- HOWTO: BCC to libbpf conversion
- libbpf-tools in BCC repo contain lots of real-world tools converted from BCC to BPF CO-RE. Consider converting some more to both contribute to the BPF community and gain some more experience with it.
Details
This is a mirror of bpf-next Linux source
tree's
tools/lib/bpf directory plus its supporting header files.
All the gory details of syncing can be found in scripts/sync-kernel.sh
script.
Some header files in this repo (include/linux/*.h) are reduced versions of
their counterpart files at
bpf-next's
tools/include/linux/*.h to make compilation successful.
License
This work is dual-licensed under BSD 2-clause license and GNU LGPL v2.1 license. You can choose between one of them if you use this work.
SPDX-License-Identifier: BSD-2-Clause OR LGPL-2.1