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path: root/tools/lib/bpf/libbpf.h
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2026-06-07libbpf: Add support to create tracing multi linkJiri Olsa
Adding bpf_program__attach_tracing_multi function for attaching tracing program to multiple functions. struct bpf_link * bpf_program__attach_tracing_multi(const struct bpf_program *prog, const char *pattern, const struct bpf_tracing_multi_opts *opts); User can specify functions to attach with 'pattern' argument that allows wildcards (*?' supported) or provide BTF ids of functions in array directly via opts argument. These options are mutually exclusive. When using BTF ids, user can also provide cookie value for each provided id/function, that can be retrieved later in bpf program with bpf_get_attach_cookie helper. Each cookie value is paired with provided BTF id with the same array index. Adding support to auto attach programs with following sections: fsession.multi/<pattern> fsession.multi.s/<pattern> fentry.multi/<pattern> fexit.multi/<pattern> fentry.multi.s/<pattern> fexit.multi.s/<pattern> The provided <pattern> is used as 'pattern' argument in bpf_program__attach_kprobe_multi_opts function. The <pattern> allows to specify optional kernel module name with following syntax: <module>:<function_pattern> In order to attach tracing_multi link to a module functions: - program must be loaded with 'module' btf fd (in attr::attach_btf_obj_fd) - bpf_program__attach_tracing_multi must either have pattern with module spec or BTF ids from the module Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20260606123955.345967-21-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-04-02libbpf: Clarify raw-address single kprobe attach behaviorHoyeon Lee
bpf_program__attach_kprobe_opts() documents single-kprobe attach through func_name, with an optional offset. For the PMU-based path, func_name = NULL with an absolute address in offset already works as well, but that is not described in the API. This commit clarifies this existing non-legacy behavior. For PMU-based attach, callers can use func_name = NULL with an absolute address in offset as the raw-address form. For legacy tracefs/debugfs kprobes, reject this form explicitly. Signed-off-by: Hoyeon Lee <hoyeon.lee@suse.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20260401143116.185049-3-hoyeon.lee@suse.com
2026-03-21libbpf: Introduce bpf_program__clone()Mykyta Yatsenko
Add bpf_program__clone() API that loads a single BPF program from a prepared BPF object into the kernel, returning a file descriptor owned by the caller. After bpf_object__prepare(), callers can use bpf_program__clone() to load individual programs with custom bpf_prog_load_opts, instead of loading all programs at once via bpf_object__load(). Non-zero fields in opts override the defaults derived from the program and object internals; passing NULL opts populates everything automatically. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Link: https://lore.kernel.org/r/20260317-veristat_prepare-v4-1-74193d4cc9d9@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-06libbpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu mapsLeon Hwang
Add libbpf support for the BPF_F_CPU flag for percpu maps by embedding the cpu info into the high 32 bits of: 1. **flags**: bpf_map_lookup_elem_flags(), bpf_map__lookup_elem(), bpf_map_update_elem() and bpf_map__update_elem() 2. **opts->elem_flags**: bpf_map_lookup_batch() and bpf_map_update_batch() And the flag can be BPF_F_ALL_CPUS, but cannot be 'BPF_F_CPU | BPF_F_ALL_CPUS'. Behavior: * If the flag is BPF_F_ALL_CPUS, the update is applied across all CPUs. * If the flag is BPF_F_CPU, it updates value only to the specified CPU. * If the flag is BPF_F_CPU, lookup value only from the specified CPU. * lookup does not support BPF_F_ALL_CPUS. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Leon Hwang <leon.hwang@linux.dev> Link: https://lore.kernel.org/r/20260107022022.12843-7-leon.hwang@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-05libbpf: Add support for associating BPF program with struct_opsAmery Hung
Add low-level wrapper and libbpf API for BPF_PROG_ASSOC_STRUCT_OPS command in the bpf() syscall. Signed-off-by: Amery Hung <ameryhung@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20251203233748.668365-4-ameryhung@gmail.com
2025-11-25libbpf: Fix some incorrect @param descriptions in the comment of libbpf.hJianyun Gao
Fix up some of missing or incorrect @param descriptions for libbpf public APIs in libbpf.h. Signed-off-by: Jianyun Gao <jianyungao89@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20251118033025.11804-1-jianyungao89@gmail.com
2025-09-22libbpf: Embed and verify the metadata hash in the loaderKP Singh
To fulfill the BPF signing contract, represented as Sig(I_loader || H_meta), the generated trusted loader program must verify the integrity of the metadata. This signature cryptographically binds the loader's instructions (I_loader) to a hash of the metadata (H_meta). The verification process is embedded directly into the loader program. Upon execution, the loader loads the runtime hash from struct bpf_map i.e. BPF_PSEUDO_MAP_IDX and compares this runtime hash against an expected hash value that has been hardcoded directly by bpf_obj__gen_loader. The load from bpf_map can be improved by calling BPF_OBJ_GET_INFO_BY_FD from the kernel context after BPF_OBJ_GET_INFO_BY_FD has been updated for being called from the kernel context. The following instructions are generated: ld_imm64 r1, const_ptr_to_map // insn[0].src_reg == BPF_PSEUDO_MAP_IDX r2 = *(u64 *)(r1 + 0); ld_imm64 r3, sha256_of_map_part1 // constant precomputed by bpftool (part of H_meta) if r2 != r3 goto out; r2 = *(u64 *)(r1 + 8); ld_imm64 r3, sha256_of_map_part2 // (part of H_meta) if r2 != r3 goto out; r2 = *(u64 *)(r1 + 16); ld_imm64 r3, sha256_of_map_part3 // (part of H_meta) if r2 != r3 goto out; r2 = *(u64 *)(r1 + 24); ld_imm64 r3, sha256_of_map_part4 // (part of H_meta) if r2 != r3 goto out; ... Signed-off-by: KP Singh <kpsingh@kernel.org> Link: https://lore.kernel.org/r/20250921160120.9711-4-kpsingh@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-18libbpf: Support exclusive map creationKP Singh
Implement setters and getters that allow map to be registered as exclusive to the specified program. The registration should be done before the exclusive program is loaded. Signed-off-by: KP Singh <kpsingh@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20250914215141.15144-5-kpsingh@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-08-20libbpf: Add documentation to version and error API functionsCryolitia PukNgae
Add documentation for the following API functions: - libbpf_major_version() - libbpf_minor_version() - libbpf_version_string() - libbpf_strerror() Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250820-libbpf-doc-1-v1-1-13841f25a134@uniontech.com
2025-08-20libbpf: Export bpf_object__prepare symbolMykyta Yatsenko
Add missing LIBBPF_API macro for bpf_object__prepare function to enable its export. libbpf.map had bpf_object__prepare already listed. Fixes: 1315c28ed809 ("libbpf: Split bpf object load into prepare/load") Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20250819215119.37795-1-mykyta.yatsenko5@gmail.com
2025-08-07libbpf: Add the ability to suppress perf event enablementIlya Leoshkevich
Automatically enabling a perf event after attaching a BPF prog to it is not always desirable. Add a new "dont_enable" field to struct bpf_perf_event_opts. While introducing "enable" instead would be nicer in that it would avoid a double negation in the implementation, it would make DECLARE_LIBBPF_OPTS() less efficient. Acked-by: Eduard Zingerman <eddyz87@gmail.com> Suggested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Thomas Richter <tmricht@linux.ibm.com> Co-developed-by: Thomas Richter <tmricht@linux.ibm.com> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Link: https://lore.kernel.org/r/20250806162417.19666-2-iii@linux.ibm.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-06-09libbpf: Support link-based cgroup attach with optionsYonghong Song
Currently libbpf supports bpf_program__attach_cgroup() with signature: LIBBPF_API struct bpf_link * bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd); To support mprog style attachment, additionsl fields like flags, relative_{fd,id} and expected_revision are needed. Add a new API: LIBBPF_API struct bpf_link * bpf_program__attach_cgroup_opts(const struct bpf_program *prog, int cgroup_fd, const struct bpf_cgroup_opts *opts); where bpf_cgroup_opts contains all above needed fields. Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250606163146.2429212-1-yonghong.song@linux.dev
2025-05-28Merge tag 'bpf-next-6.16' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Pull bpf updates from Alexei Starovoitov: - Fix and improve BTF deduplication of identical BTF types (Alan Maguire and Andrii Nakryiko) - Support up to 12 arguments in BPF trampoline on arm64 (Xu Kuohai and Alexis Lothoré) - Support load-acquire and store-release instructions in BPF JIT on riscv64 (Andrea Parri) - Fix uninitialized values in BPF_{CORE,PROBE}_READ macros (Anton Protopopov) - Streamline allowed helpers across program types (Feng Yang) - Support atomic update for hashtab of BPF maps (Hou Tao) - Implement json output for BPF helpers (Ihor Solodrai) - Several s390 JIT fixes (Ilya Leoshkevich) - Various sockmap fixes (Jiayuan Chen) - Support mmap of vmlinux BTF data (Lorenz Bauer) - Support BPF rbtree traversal and list peeking (Martin KaFai Lau) - Tests for sockmap/sockhash redirection (Michal Luczaj) - Introduce kfuncs for memory reads into dynptrs (Mykyta Yatsenko) - Add support for dma-buf iterators in BPF (T.J. Mercier) - The verifier support for __bpf_trap() (Yonghong Song) * tag 'bpf-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (135 commits) bpf, arm64: Remove unused-but-set function and variable. selftests/bpf: Add tests with stack ptr register in conditional jmp bpf: Do not include stack ptr register in precision backtracking bookkeeping selftests/bpf: enable many-args tests for arm64 bpf, arm64: Support up to 12 function arguments bpf: Check rcu_read_lock_trace_held() in bpf_map_lookup_percpu_elem() bpf: Avoid __bpf_prog_ret0_warn when jit fails bpftool: Add support for custom BTF path in prog load/loadall selftests/bpf: Add unit tests with __bpf_trap() kfunc bpf: Warn with __bpf_trap() kfunc maybe due to uninitialized variable bpf: Remove special_kfunc_set from verifier selftests/bpf: Add test for open coded dmabuf_iter selftests/bpf: Add test for dmabuf_iter bpf: Add open coded dmabuf iterator bpf: Add dmabuf iterator dma-buf: Rename debugfs symbols bpf: Fix error return value in bpf_copy_from_user_dynptr libbpf: Use mmap to parse vmlinux BTF from sysfs selftests: bpf: Add a test for mmapable vmlinux BTF btf: Allow mmap of vmlinux btf ...
2025-04-17libbpf: Support creating and destroying qdiscAmery Hung
Extend struct bpf_tc_hook with handle, qdisc name and a new attach type, BPF_TC_QDISC, to allow users to add or remove any qdisc specified in addition to clsact. Signed-off-by: Amery Hung <amery.hung@bytedance.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://patch.msgid.link/20250409214606.2000194-8-ameryhung@gmail.com
2025-04-09libbpf: Add getters for BTF.ext func and line infoMykyta Yatsenko
Introducing new libbpf API getters for BTF.ext func and line info, namely: bpf_program__func_info bpf_program__func_info_cnt bpf_program__line_info bpf_program__line_info_cnt This change enables scenarios, when user needs to load bpf_program directly using `bpf_prog_load`, instead of higher-level `bpf_object__load`. Line and func info are required for checking BTF info in verifier; verification may fail without these fields if, for example, program calls `bpf_obj_new`. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250408234417.452565-2-mykyta.yatsenko5@gmail.com
2025-03-15libbpf: Split bpf object load into prepare/loadMykyta Yatsenko
Introduce bpf_object__prepare API: additional intermediate preparation step that performs ELF processing, relocations, prepares final state of BPF program instructions (accessible with bpf_program__insns()), creates and (potentially) pins maps, and stops short of loading BPF programs. We anticipate few use cases for this API, such as: * Use prepare to initialize bpf_token, without loading freplace programs, unlocking possibility to lookup BTF of other programs. * Execute prepare to obtain finalized BPF program instructions without loading programs, enabling tools like veristat to process one program at a time, without incurring cost of ELF parsing and processing. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250303135752.158343-4-mykyta.yatsenko5@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-01-10libbpf: Add unique_match option for multi kprobeYonghong Song
Jordan reported an issue in Meta production environment where func try_to_wake_up() is renamed to try_to_wake_up.llvm.<hash>() by clang compiler at lto mode. The original 'kprobe/try_to_wake_up' does not work any more since try_to_wake_up() does not match the actual func name in /proc/kallsyms. There are a couple of ways to resolve this issue. For example, in attach_kprobe(), we could do lookup in /proc/kallsyms so try_to_wake_up() can be replaced by try_to_wake_up.llvm.<hach>(). Or we can force users to use bpf_program__attach_kprobe() where they need to lookup /proc/kallsyms to find out try_to_wake_up.llvm.<hach>(). But these two approaches requires extra work by either libbpf or user. Luckily, suggested by Andrii, multi kprobe already supports wildcard ('*') for symbol matching. In the above example, 'try_to_wake_up*' can match to try_to_wake_up() or try_to_wake_up.llvm.<hash>() and this allows bpf prog works for different kernels as some kernels may have try_to_wake_up() and some others may have try_to_wake_up.llvm.<hash>(). The original intention is to kprobe try_to_wake_up() only, so an optional field unique_match is added to struct bpf_kprobe_multi_opts. If the field is set to true, the number of matched functions must be one. Otherwise, the attachment will fail. In the above case, multi kprobe with 'try_to_wake_up*' and unique_match preserves user functionality. Reported-by: Jordan Rome <linux@jordanrome.com> Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250109174023.3368432-1-yonghong.song@linux.dev
2024-12-12libbpf: Extend linker API to support in-memory ELF filesAlastair Robertson
The new_fd and add_fd functions correspond to the original new and add_file functions, but accept an FD instead of a file name. This gives API consumers the option of using anonymous files/memfds to avoid writing ELFs to disk. This new API will be useful for performing linking as part of bpftrace's JIT compilation. The add_buf function is a convenience wrapper that does the work of creating a memfd for the caller. Signed-off-by: Alastair Robertson <ajor@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20241211164030.573042-3-ajor@meta.com
2024-11-11libbpf: Add support for uprobe multi session attachJiri Olsa
Adding support to attach program in uprobe session mode with bpf_program__attach_uprobe_multi function. Adding session bool to bpf_uprobe_multi_opts struct that allows to load and attach the bpf program via uprobe session. the attachment to create uprobe multi session. Also adding new program loader section that allows: SEC("uprobe.session/bpf_fentry_test*") and loads/attaches uprobe program as uprobe session. Adding sleepable hook (uprobe.session.s) as well. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20241108134544.480660-6-jolsa@kernel.org
2024-09-12libbpf: Add bpf_object__token_fd accessorIhor Solodrai
Add a LIBBPF_API function to retrieve the token_fd from a bpf_object. Without this accessor, if user needs a token FD they have to get it manually via bpf_token_create, even though a token might have been already created by bpf_object__load. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Ihor Solodrai <ihor.solodrai@pm.me> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240913001858.3345583-1-ihor.solodrai@pm.me
2024-09-09libbpf: Fix some typos in commentsYusheng Zheng
Fix some spelling errors in the code comments of libbpf: betwen -> between paremeters -> parameters knowning -> knowing definiton -> definition compatiblity -> compatibility overriden -> overridden occured -> occurred proccess -> process managment -> management nessary -> necessary Signed-off-by: Yusheng Zheng <yunwei356@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240909225952.30324-1-yunwei356@gmail.com
2024-06-06libbpf: Auto-attach struct_ops BPF maps in BPF skeletonMykyta Yatsenko
Similarly to `bpf_program`, support `bpf_map` automatic attachment in `bpf_object__attach_skeleton`. Currently only struct_ops maps could be attached. On bpftool side, code-generate links in skeleton struct for struct_ops maps. Similarly to `bpf_program_skeleton`, set links in `bpf_map_skeleton`. On libbpf side, extend `bpf_map` with new `autoattach` field to support enabling or disabling autoattach functionality, introducing getter/setter for this field. `bpf_object__(attach|detach)_skeleton` is extended with attaching/detaching struct_ops maps logic. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240605175135.117127-1-yatsenko@meta.com
2024-05-28libbpf: Configure log verbosity with env variableMykyta Yatsenko
Configure logging verbosity by setting LIBBPF_LOG_LEVEL environment variable, which is applied only to default logger. Once user set their custom logging callback, it is up to them to handle filtering. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240524131840.114289-1-yatsenko@meta.com
2024-04-30libbpf: Add support for kprobe session attachJiri Olsa
Adding support to attach program in kprobe session mode with bpf_program__attach_kprobe_multi_opts function. Adding session bool to bpf_kprobe_multi_opts struct that allows to load and attach the bpf program via kprobe session. the attachment to create kprobe multi session. Also adding new program loader section that allows: SEC("kprobe.session/bpf_fentry_test*") and loads/attaches kprobe program as kprobe session. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240430112830.1184228-5-jolsa@kernel.org
2024-04-10libbpf: Add bpf_link support for BPF_PROG_TYPE_SOCKMAPYonghong Song
Introduce a libbpf API function bpf_program__attach_sockmap() which allow user to get a bpf_link for their corresponding programs. Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Reviewed-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20240410043532.3737722-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-06libbpf: Add ring__consume_n / ring_buffer__consume_nAndrea Righi
Introduce a new API to consume items from a ring buffer, limited to a specified amount, and return to the caller the actual number of items consumed. Signed-off-by: Andrea Righi <andrea.righi@canonical.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/lkml/20240310154726.734289-1-andrea.righi@canonical.com/T Link: https://lore.kernel.org/bpf/20240406092005.92399-4-andrea.righi@canonical.com
2024-03-19libbpf: add support for BPF cookie for raw_tp/tp_btf programsAndrii Nakryiko
Wire up BPF cookie passing or raw_tp and tp_btf programs, both in low-level and high-level APIs. Acked-by: Stanislav Fomichev <sdf@google.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Message-ID: <20240319233852.1977493-5-andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-11libbpf: Recognize __arena global variables.Andrii Nakryiko
LLVM automatically places __arena variables into ".arena.1" ELF section. In order to use such global variables bpf program must include definition of arena map in ".maps" section, like: struct { __uint(type, BPF_MAP_TYPE_ARENA); __uint(map_flags, BPF_F_MMAPABLE); __uint(max_entries, 1000); /* number of pages */ __ulong(map_extra, 2ull << 44); /* start of mmap() region */ } arena SEC(".maps"); libbpf recognizes both uses of arena and creates single `struct bpf_map *` instance in libbpf APIs. ".arena.1" ELF section data is used as initial data image, which is exposed through skeleton and bpf_map__initial_value() to the user, if they need to tune it before the load phase. During load phase, this initial image is copied over into mmap()'ed region corresponding to arena, and discarded. Few small checks here and there had to be added to make sure this approach works with bpf_map__initial_value(), mostly due to hard-coded assumption that map->mmaped is set up with mmap() syscall and should be munmap()'ed. For arena, .arena.1 can be (much) smaller than maximum arena size, so this smaller data size has to be tracked separately. Given it is enforced that there is only one arena for entire bpf_object instance, we just keep it in a separate field. This can be generalized if necessary later. All global variables from ".arena.1" section are accessible from user space via skel->arena->name_of_var. For bss/data/rodata the skeleton/libbpf perform the following sequence: 1. addr = mmap(MAP_ANONYMOUS) 2. user space optionally modifies global vars 3. map_fd = bpf_create_map() 4. bpf_update_map_elem(map_fd, addr) // to store values into the kernel 5. mmap(addr, MAP_FIXED, map_fd) after step 5 user spaces see the values it wrote at step 2 at the same addresses arena doesn't support update_map_elem. Hence skeleton/libbpf do: 1. addr = malloc(sizeof SEC ".arena.1") 2. user space optionally modifies global vars 3. map_fd = bpf_create_map(MAP_TYPE_ARENA) 4. real_addr = mmap(map->map_extra, MAP_SHARED | MAP_FIXED, map_fd) 5. memcpy(real_addr, addr) // this will fault-in and allocate pages At the end look and feel of global data vs __arena global data is the same from bpf prog pov. Another complication is: struct { __uint(type, BPF_MAP_TYPE_ARENA); } arena SEC(".maps"); int __arena foo; int bar; ptr1 = &foo; // relocation against ".arena.1" section ptr2 = &arena; // relocation against ".maps" section ptr3 = &bar; // relocation against ".bss" section Fo the kernel ptr1 and ptr2 has point to the same arena's map_fd while ptr3 points to a different global array's map_fd. For the verifier: ptr1->type == unknown_scalar ptr2->type == const_ptr_to_map ptr3->type == ptr_to_map_value After verification, from JIT pov all 3 ptr-s are normal ld_imm64 insns. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20240308010812.89848-11-alexei.starovoitov@gmail.com
2024-01-24libbpf: Support BPF token path setting through LIBBPF_BPF_TOKEN_PATH envvarAndrii Nakryiko
To allow external admin authority to override default BPF FS location (/sys/fs/bpf) for implicit BPF token creation, teach libbpf to recognize LIBBPF_BPF_TOKEN_PATH envvar. If it is specified and user application didn't explicitly specify bpf_token_path option, it will be treated exactly like bpf_token_path option, overriding default /sys/fs/bpf location and making BPF token mandatory. Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20240124022127.2379740-29-andrii@kernel.org
2024-01-24libbpf: Wire up BPF token support at BPF object levelAndrii Nakryiko
Add BPF token support to BPF object-level functionality. BPF token is supported by BPF object logic either as an explicitly provided BPF token from outside (through BPF FS path), or implicitly (unless prevented through bpf_object_open_opts). Implicit mode is assumed to be the most common one for user namespaced unprivileged workloads. The assumption is that privileged container manager sets up default BPF FS mount point at /sys/fs/bpf with BPF token delegation options (delegate_{cmds,maps,progs,attachs} mount options). BPF object during loading will attempt to create BPF token from /sys/fs/bpf location, and pass it for all relevant operations (currently, map creation, BTF load, and program load). In this implicit mode, if BPF token creation fails due to whatever reason (BPF FS is not mounted, or kernel doesn't support BPF token, etc), this is not considered an error. BPF object loading sequence will proceed with no BPF token. In explicit BPF token mode, user provides explicitly custom BPF FS mount point path. In such case, BPF object will attempt to create BPF token from provided BPF FS location. If BPF token creation fails, that is considered a critical error and BPF object load fails with an error. Libbpf provides a way to disable implicit BPF token creation, if it causes any troubles (BPF token is designed to be completely optional and shouldn't cause any problems even if provided, but in the world of BPF LSM, custom security logic can be installed that might change outcome depending on the presence of BPF token). To disable libbpf's default BPF token creation behavior user should provide either invalid BPF token FD (negative), or empty bpf_token_path option. BPF token presence can influence libbpf's feature probing, so if BPF object has associated BPF token, feature probing is instructed to use BPF object-specific feature detection cache and token FD. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20240124022127.2379740-26-andrii@kernel.org
2023-10-24libbpf: Add link-based API for netkitDaniel Borkmann
This adds bpf_program__attach_netkit() API to libbpf. Overall it is very similar to tcx. The API looks as following: LIBBPF_API struct bpf_link * bpf_program__attach_netkit(const struct bpf_program *prog, int ifindex, const struct bpf_netkit_opts *opts); The struct bpf_netkit_opts is done in similar way as struct bpf_tcx_opts for supporting bpf_mprog control parameters. The attach location for the primary and peer device is derived from the program section "netkit/primary" and "netkit/peer", respectively. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20231024214904.29825-4-daniel@iogearbox.net Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-09-25libbpf: Add ring__consumeMartin Kelly
Add ring__consume to consume a single ringbuffer, analogous to ring_buffer__consume. Signed-off-by: Martin Kelly <martin.kelly@crowdstrike.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230925215045.2375758-14-martin.kelly@crowdstrike.com
2023-09-25libbpf: Add ring__map_fdMartin Kelly
Add ring__map_fd to get the file descriptor underlying a given ringbuffer. Signed-off-by: Martin Kelly <martin.kelly@crowdstrike.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230925215045.2375758-12-martin.kelly@crowdstrike.com
2023-09-25libbpf: Add ring__sizeMartin Kelly
Add ring__size to get the total size of a given ringbuffer. Signed-off-by: Martin Kelly <martin.kelly@crowdstrike.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230925215045.2375758-10-martin.kelly@crowdstrike.com
2023-09-25libbpf: Add ring__avail_data_sizeMartin Kelly
Add ring__avail_data_size for querying the currently available data in the ringbuffer, similar to the BPF_RB_AVAIL_DATA flag in bpf_ringbuf_query. This is racy during ongoing operations but is still useful for overall information on how a ringbuffer is behaving. Signed-off-by: Martin Kelly <martin.kelly@crowdstrike.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230925215045.2375758-8-martin.kelly@crowdstrike.com
2023-09-25libbpf: Add ring__producer_pos, ring__consumer_posMartin Kelly
Add APIs to get the producer and consumer position for a given ringbuffer. Signed-off-by: Martin Kelly <martin.kelly@crowdstrike.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230925215045.2375758-6-martin.kelly@crowdstrike.com
2023-09-25libbpf: Add ring_buffer__ringMartin Kelly
Add a new function ring_buffer__ring, which exposes struct ring * to the user, representing a single ringbuffer. Signed-off-by: Martin Kelly <martin.kelly@crowdstrike.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230925215045.2375758-4-martin.kelly@crowdstrike.com
2023-08-23libbpf: Add bpf_object__unpin()Daniel Xu
For bpf_object__pin_programs() there is bpf_object__unpin_programs(). Likewise bpf_object__unpin_maps() for bpf_object__pin_maps(). But no bpf_object__unpin() for bpf_object__pin(). Adding the former adds symmetry to the API. It's also convenient for cleanup in application code. It's an API I would've used if it was available for a repro I was writing earlier. Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/bpf/b2f9d41da4a350281a0b53a804d11b68327e14e5.1692832478.git.dxu@dxuuu.xyz
2023-08-21libbpf: Add bpf_program__attach_uprobe_multi functionJiri Olsa
Adding bpf_program__attach_uprobe_multi function that allows to attach multiple uprobes with uprobe_multi link. The user can specify uprobes with direct arguments: binary_path/func_pattern/pid or with struct bpf_uprobe_multi_opts opts argument fields: const char **syms; const unsigned long *offsets; const unsigned long *ref_ctr_offsets; const __u64 *cookies; User can specify 2 mutually exclusive set of inputs: 1) use only path/func_pattern/pid arguments 2) use path/pid with allowed combinations of: syms/offsets/ref_ctr_offsets/cookies/cnt - syms and offsets are mutually exclusive - ref_ctr_offsets and cookies are optional Any other usage results in error. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230809083440.3209381-15-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19libbpf: Add link-based API for tcxDaniel Borkmann
Implement tcx BPF link support for libbpf. The bpf_program__attach_fd() API has been refactored slightly in order to pass bpf_link_create_opts pointer as input. A new bpf_program__attach_tcx() has been added on top of this which allows for passing all relevant data via extensible struct bpf_tcx_opts. The program sections tcx/ingress and tcx/egress correspond to the hook locations for tc ingress and egress, respectively. For concrete usage examples, see the extensive selftests that have been developed as part of this series. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230719140858.13224-5-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19xsk: add new netlink attribute dedicated for ZC max fragsMaciej Fijalkowski
Introduce new netlink attribute NETDEV_A_DEV_XDP_ZC_MAX_SEGS that will carry maximum fragments that underlying ZC driver is able to handle on TX side. It is going to be included in netlink response only when driver supports ZC. Any value higher than 1 implies multi-buffer ZC support on underlying device. Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/r/20230719132421.584801-11-maciej.fijalkowski@intel.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-06-30libbpf: Add netfilter link attach helperFlorian Westphal
Add new api function: bpf_program__attach_netfilter. It takes a bpf program (netfilter type), and a pointer to a option struct that contains the desired attachment (protocol family, priority, hook location, ...). It returns a pointer to a 'bpf_link' structure or NULL on error. Next patch adds new netfilter_basic test that uses this function to attach a program to a few pf/hook/priority combinations. v2: change name and use bpf_link_create. Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Acked-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lore.kernel.org/bpf/CAEf4BzZrmUv27AJp0dDxBDMY_B8e55-wLs8DUKK69vCWsCG_pQ@mail.gmail.com/ Link: https://lore.kernel.org/bpf/CAEf4BzZ69YgrQW7DHCJUT_X+GqMq_ZQQPBwopaJJVGFD5=d5Vg@mail.gmail.com/ Link: https://lore.kernel.org/bpf/20230628152738.22765-2-fw@strlen.de
2023-05-24libbpf: Add capability for resizing datasec mapsJP Kobryn
This patch updates bpf_map__set_value_size() so that if the given map is memory mapped, it will attempt to resize the mapped region. Initial contents of the mapped region are preserved. BTF is not required, but after the mapping is resized an attempt is made to adjust the associated BTF information if the following criteria is met: - BTF info is present - the map is a datasec - the final variable in the datasec is an array ... the resulting BTF info will be updated so that the final array variable is associated with a new BTF array type sized to cover the requested size. Note that the initial resizing of the memory mapped region can succeed while the subsequent BTF adjustment can fail. In this case, BTF info is dropped from the map by clearing the key and value type. Signed-off-by: JP Kobryn <inwardvessel@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20230524004537.18614-2-inwardvessel@gmail.com
2023-03-27libbpf: Ensure print callback usage is thread-safeJP Kobryn
This patch prevents races on the print function pointer, allowing the libbpf_set_print() function to become thread-safe. Signed-off-by: JP Kobryn <inwardvessel@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230325010845.46000-1-inwardvessel@gmail.com
2023-03-22libbpf: Update a bpf_link with another struct_ops.Kui-Feng Lee
Introduce bpf_link__update_map(), which allows to atomically update underlying struct_ops implementation for given struct_ops BPF link. Also add old_map_fd to struct bpf_link_update_opts to handle BPF_F_REPLACE feature. Signed-off-by: Kui-Feng Lee <kuifeng@meta.com> Link: https://lore.kernel.org/r/20230323032405.3735486-7-kuifeng@meta.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-03-06libbpf: Add support to set kprobe/uprobe attach modeMenglong Dong
By default, libbpf will attach the kprobe/uprobe BPF program in the latest mode that supported by kernel. In this patch, we add the support to let users manually attach kprobe/uprobe in legacy or perf mode. There are 3 mode that supported by the kernel to attach kprobe/uprobe: LEGACY: create perf event in legacy way and don't use bpf_link PERF: create perf event with perf_event_open() and don't use bpf_link Signed-off-by: Menglong Dong <imagedong@tencent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Biao Jiang <benbjiang@tencent.com> Link: create perf event with perf_event_open() and use bpf_link Link: https://lore.kernel.org/bpf/20230113093427.1666466-1-imagedong@tencent.com/ Link: https://lore.kernel.org/bpf/20230306064833.7932-2-imagedong@tencent.com Users now can manually choose the mode with bpf_program__attach_uprobe_opts()/bpf_program__attach_kprobe_opts().
2023-02-08libbpf: Add sample_period to creation optionsJon Doron
Add option to set when the perf buffer should wake up, by default the perf buffer becomes signaled for every event that is being pushed to it. In case of a high throughput of events it will be more efficient to wake up only once you have X events ready to be read. So your application can wakeup once and drain the entire perf buffer. Signed-off-by: Jon Doron <jond@wiz.io> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230207081916.3398417-1-arilou@gmail.com
2023-02-02libbpf: add API to get XDP/XSK supported featuresLorenzo Bianconi
Extend bpf_xdp_query routine in order to get XDP/XSK supported features of netdev over route netlink interface. Extend libbpf netlink implementation in order to support netlink_generic protocol. Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Co-developed-by: Marek Majtyka <alardam@gmail.com> Signed-off-by: Marek Majtyka <alardam@gmail.com> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> Link: https://lore.kernel.org/r/a72609ef4f0de7fee5376c40dbf54ad7f13bfb8d.1675245258.git.lorenzo@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-27libbpf: Add documentation to map pinning API functionsGrant Seltzer
This adds documentation for the following API functions: - bpf_map__set_pin_path() - bpf_map__pin_path() - bpf_map__is_pinned() - bpf_map__pin() - bpf_map__unpin() - bpf_object__pin_maps() - bpf_object__unpin_maps() Signed-off-by: Grant Seltzer <grantseltzer@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230126024225.520685-1-grantseltzer@gmail.com
2023-01-27libbpf: Fix malformed documentation formattingGrant Seltzer
This fixes the doxygen format documentation above the user_ring_buffer__* APIs. There has to be a newline before the @brief, otherwise doxygen won't render them for libbpf.readthedocs.org. Signed-off-by: Grant Seltzer <grantseltzer@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230126024749.522278-1-grantseltzer@gmail.com